JP2006097013A - Polyester composition and polyester molded product comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition from which the formation of acetaldehyde at molding is reduced, which has excellent color and transparency, which has no problems in change of the transparency, crystallization rate, and change of the crystallization rate, and from which a hollow molded product having excellent heat resistant dimensional stability, especially a hollow molded product having excellent pressure resistance and heat resistance is produced by a high-speed molding in good efficiency; and to provide the polyester molded product comprising the composition. <P>SOLUTION: The polyester composition comprises at least two kinds of polyesters having substantially the same composition and different intrinsic viscosities, and at least one kind of polyamide. The difference of the intrinsic viscosities between at least two kinds of the polyesters is 0.05-0.30 dl/g. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a hollow molded body including beverage bottles, a sheet-like article, a molded article such as a stretched film, and a coating coated on a substrate such as paper or film (hereinafter, these uses are referred to as “ A polyester composition suitably used as a raw material such as a molded article) and a polyester molded article comprising the polyester composition, in particular, the formation of acetaldehyde at the time of molding is suppressed, excellent in hue and transparency, fluctuations in transparency, There are no problems in terms of crystallization speed and fluctuation in crystallization speed, and there are no hollow molded articles excellent in heat resistance, and molded articles such as sheet-like products and stretched films excellent in transparency, slipperiness and dimensional stability after molding. It is about.

  Polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”) are excellent in both mechanical properties and chemical properties, and thus have high industrial value, such as fibers, films, sheets, and bottles. Widely used as such.

  As a material for containers such as seasonings, oils, beverages, cosmetics, and detergents, various resins are employed depending on the type of filling contents and the purpose of use.

  Of these, polyester is excellent in mechanical strength, heat resistance, transparency and gas barrier properties, and is particularly suitable as a material for molded articles such as beverage filling containers such as juices, soft drinks and carbonated drinks. is there.

  For example, such polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape and stretched blow molded to cool it. It is made into a hollow molded container for beverages, or it is molded into a heat-resistant or pressure-resistant hollow molded container by heat-treating the preform plug part (crystallization of the plug part) and then stretching blow molding and heat-treating the body part (heat set). It is common.

  However, PET contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. Moreover, PET produced acetaldehyde by thermal decomposition when thermoforming a molded body such as a hollow molded body, and the acetaldehyde content in the material of the obtained molded body was increased, and the hollow molded body was filled. Affects the flavor and odor of beverages.

  In recent years, polyester containers mainly made of polyethylene terephthalate have come to be used as containers for low flavor beverages such as mineral water and oolong tea. In the case of such beverages, these beverages are generally heat-filled or sterilized by heating after filling, but it is becoming increasingly important to reduce the acetaldehyde content of the beverage container. In addition, for beverage metal cans, for the purposes of process simplification, hygiene, pollution prevention, etc., cans are made using a metal plate whose inner surface is coated with a polyester film whose main repeating unit is ethylene terephthalate. The method to do has come to be adopted. In this case as well, it is sterilized by heating at a high temperature after filling the contents. At this time, it is found that the use of a film having a sufficiently low acetaldehyde content is an essential requirement for improving the flavor and odor of the contents. I came.

  For these reasons, various measures have been taken to reduce the acetaldehyde content in the polyester. As these measures, for example, a method of reducing the AA content by solid-phase polymerization of melt-polycondensed polyester (see, for example, Patent Document 1), AA at the time of molding using a copolyester having a lower melting point Method for reducing production (for example, see Patent Document 2), Method for reducing oligomers and aldehydes by subjecting a polyester prepolymer obtained by melt polymerization to solid phase polymerization under reduced pressure or in the flow of an inert gas (For example, refer to Patent Documents 3 and 4), a method for crystallization and solid-phase polymerization after conditioning the polyester prepolymer so that the moisture content is 2000 ppm or more (for example, refer to Patent Document 5), A method of performing heat treatment under reduced pressure or inert gas flow after treatment with hot water at ˜200 ° C. (for example, patent document) 6), a method of extracting and washing with water or an organic solvent before and after solid-phase polymerization (see, for example, Patent Document 7), a method of reducing the molding temperature as much as possible during thermoforming, and shearing during thermoforming A method for reducing the stress as much as possible has been proposed. However, even in a molded body using polyester obtained by these methods, it cannot be said that oligomers and acetaldehyde can be reduced to a problem-free level, and the problem remains unsolved.

  In addition, a method using a polyester composition in which 0.05 parts by weight or more and less than 1 part by weight of a metaxylylene group-containing polyamide resin is added to 100 parts by weight of a polyester resin (see, for example, Patent Document 8) or thermoplastic polyester A polyester container made of a polyester composition containing a specific polyamide whose terminal amino group concentration is regulated within a certain range has been proposed (for example, see Patent Document 9), and the degree of acetaldehyde content reduction and the crystallization rate are proposed. There are still problems in terms of fluctuations.

Further, a blend of solid-phase polymerized PET and copolymerized polyethylene terephthalate (for example, see Patent Document 10) has been proposed, and by using this, the AA content of the hollow molded body can be reduced. Since the copolymer component is present, there is a problem in the heat resistance and pressure resistance of the obtained molded body, which is not satisfactory and a solution is awaited.
In recent years, thinning of bottles has been attempted, and as a result, attempts have been made to increase the molecular weight in order to increase the strength of the bottle, but by increasing the molecular weight, the melt viscosity during molding increases and the amount of acetaldehyde generated increases. There was an increasing problem.

JP-A-53-73288 Japanese Patent Laid-Open No. 57-16024 JP 55-89330 A JP 55-89331 A JP-A-2-298512 JP-A-8-120062 Japanese Patent Laid-Open No. 55-13715 Japanese Examined Patent Publication No. 6-6661 Japanese Examined Patent Publication No. 4-71425 JP 58-45254 A

  The present invention solves the problems of the above conventional methods, suppresses the formation of acetaldehyde during molding, is excellent in hue and transparency, has problems in terms of variation in transparency, crystallization rate, and crystallization rate variation. There is provided a polyester composition that can efficiently produce a hollow molded article having no heat resistance, particularly a hollow molded article excellent in pressure resistance and heat and pressure resistance by high-speed molding, and a polyester molded article comprising the same. With the goal.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to achieve the above object. That is, the polyester composition of the present invention is a polyester composition comprising at least two polyesters having substantially the same composition and different intrinsic viscosities and at least one polyamide as main components, The polyester composition is characterized in that a difference in intrinsic viscosity between at least two kinds of the polyester is in a range of 0.05 to 0.30 deciliter / gram.
Here, “substantially the same” means that the acid component and glycol component in each composition are preferably 95 mol% or more, more preferably 97 mol% or more, particularly 98 mol% or more. It is preferable that

In addition, the polyester composition of the present invention contains the following polyester A and polyester B having ethylene terephthalate as a main repeating unit as main components, and further polyamide in an amount of 0.01 to 30 parts per 100 parts by weight of the total polyester. A polyester composition containing parts by weight, wherein the difference between the intrinsic viscosity IV _A of polyester _A and the intrinsic viscosity IV _B of polyester B is in the range of 0.05 to 0.30 deciliter / gram, and the crystallization temperature of polyester A when the temperature is lowered The polyester composition is characterized in that the difference in crystallization temperature when the temperature of polyester B is lowered is within 15 ° C.
Polyester A: Polyester having intrinsic viscosity IV _A of 0.60 to 0.80 deciliter / gram, crystallization temperature measured by DSC at 140 to 178 ° C., and crystallization temperature at 160 to 190 ° C. .
Polyester B: Polyester having intrinsic viscosity IV _B of 0.73 to 0.95 deciliter / gram, crystallization temperature measured by DSC at 140 to 178 ° C., and crystallization temperature at 160 to 190 ° C. .
Here, the DSC measurement is performed by the following method on a molded plate (2 mm thickness) injection-molded at 290 ° C. by the following method.

  The blending amount of the polyamide in the polyester composition of the present invention is preferably 0.05 to 18 parts by weight, more preferably 0.1 to 15 parts by weight, and most preferably 0.1 to 13 parts by weight. When the blending amount is less than 0.01 parts by weight, the AA content of the obtained molded product is not reduced, and the flavor retention of the molded product content becomes very poor. On the other hand, when the blending amount of polyamide exceeds 30 parts by weight with respect to 100 parts by weight of the polyester, the transparency of the obtained molded product becomes very poor, and the mechanical properties of the molded product also deteriorate.

The difference between the intrinsic viscosity IV _A of polyester _A and the intrinsic viscosity IV _B of polyester B is preferably 0.06 to 0.27 deciliter / gram, more preferably 0.07 to 0.23 deciliter / gram, particularly preferably 0. 10 to 0.20 deciliters per gram. When the above-mentioned intrinsic viscosity difference is less than 0.05 deciliter / gram, the acetaldehyde content of the obtained molded product cannot be reduced, and the flavor retention cannot be improved. Further, when the above-mentioned intrinsic viscosity difference exceeds 0.30 deciliter / gram, a thickness unevenness, a whitened flow pattern, or the like is generated on the obtained molded product, which causes a problem.
Further, the difference between the crystallization temperature when the temperature of the polyester A is lowered and the crystallization temperature when the temperature of the polyester B is lowered is preferably within 13 ° C, more preferably within 10 ° C, and particularly preferably within 8 ° C. When the difference in the crystallization temperature at the time of the temperature drop exceeds 15 ° C., the transparency of the obtained molded product becomes very poor, the fluctuation of the crystallization speed during crystallization of the plug portion becomes large, and the dimensional accuracy is poor. It is a problem. In addition, the lower limit of the difference in crystallization temperature when the temperature is lowered is 2 ° C. or more, and if it is less than this, the difference in effect is not clear.

The intrinsic viscosity IV _A of polyester A is preferably 0.62 to 0.78 deciliter / gram, more preferably 0.65 to 0.75 deciliter / gram, and the crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C. More preferably, it is 150-175 degreeC, The crystallization temperature at the time of temperature fall becomes like this. Preferably it is 162-185 degreeC, More preferably, it is 165-180 degreeC. If the intrinsic viscosity IV _A of the polyester A is less than 0.60 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.80 deciliter / gram, the effect of reducing acetaldehyde is lowered. Further, when the crystallization temperature of polyester A at the time of temperature rise is less than 140 ° C., the transparency of the molded article is deteriorated, and when it exceeds 178 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated. When the crystallization temperature of the polyester A when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization speed of the plug portion is deteriorated, and when it exceeds 190 ° C., the transparency of the molded article is deteriorated.

The intrinsic viscosity IV _B of polyester B is preferably 0.74 to 0.86 deciliter / gram, more preferably 0.75 to 0.84 deciliter / gram, and the crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C. More preferably, it is 150-175 degreeC, The crystallization temperature at the time of temperature fall becomes like this. Preferably it is 162-185 degreeC, More preferably, it is 165-180 degreeC. The intrinsic viscosity of the polyester B IV _B If there is less than 0.73 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.90 deciliter / gram, heat generation during molding becomes intense and the effect of reducing acetaldehyde becomes low. Moreover, when the crystallization temperature at the time of temperature rising of polyester B is less than 140 degreeC, the transparency of a molded object worsens, and when it exceeds 178 degreeC, the crystallization speed improvement effect of a plug part worsens and is a problem. When the crystallization temperature of the polyester B when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated, and when it exceeds 190 ° C., the transparency of the molded article is deteriorated.

  By using the polyester composition of the present invention, the content of aldehydes such as acetaldehyde is low, the color tone, flavor retention and transparency are excellent, and transparent spots (for example, a whitened flow pattern generated in a molded product) And a hollow molded article having an appropriate crystallization rate and little fluctuation in the crystallization rate can be obtained. In particular, in the case of a thick stretched molded product such as a bottle, these effects become significant.

  The polyester composition of the present invention has improved mechanical properties such as elastic modulus and tensile strength, as well as improved heat fixability since the fluidity at the time of melting is improved and the orientation at the time of heat stretching is also improved. An excellent stretch molded body can be provided, and it is beneficially used as a stretched hollow container particularly excellent in heat resistance or heat and pressure resistance.

  In the polyester composition of the present invention, the blending ratio of the polyester A and the polyester B is 95/5 to 5/95, preferably 92/8 to 8/92, more preferably 90/10 to 10/90, in weight ratio. If it is out of this range, the object of the present invention is not achieved, which is not desirable.

In this case, the polyamide is preferably a partially aromatic polyamide.
In this case, the partially aromatic polyamide is preferably a polyamide containing at least 70 mol% or more of repeating units composed of metaxylylenediamine and adipic acid.

In this case, it is preferable that the acetaldehyde content of the molded body from the polyester composition is 15 ppm or less. The acetaldehyde content is preferably 10 ppm or less, more preferably 8 ppm or less, and particularly preferably 6 ppm or less. If it exceeds 15 ppm, the flavor retention is poor, and is not particularly suitable for containers of low flavor beverages such as mineral water.
Here, the acetaldehyde content of the molded product is a value obtained for a sample from a 2 mm thick plate of a stepped molded plate molded at 290 ° C. according to the molding method described in the following “Measurement Method” section. .

  In this case, the cyclic ester oligomer content is preferably 70% or less of the cyclic ester oligomer content of the melt polycondensed polyester prepolymer.

In this case, it is desirable that the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less.
Here, the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is a sample from a 3 mm thick plate of a stepped molded plate obtained by the molding method described in the “Measurement method” section below. Is the value obtained for.

In this case, it is a polyester molded body obtained by melt-molding the polyester composition according to any one of claims 1 to 7, and the polyester molded body is a hollow molded body, a sheet-like product, or a sheet-like product. A polyester molded body characterized by being a stretched film obtained by stretching in a direction.
Moreover, in this case, it can be a coating characterized by melt-extruding the polyester composition according to any one of claims 1 to 7 on a substrate.

  The polyester composition has a low content of aldehydes such as acetaldehyde, is excellent in flavor retention, hue, and transparency, and has a low content of cyclic ester oligomers such as cyclic trimers, and mold stains occur during continuous molding. Can be provided, for example, a hollow molded body, a sheet-like product, a stretched film, or a coating on a substrate.

  In the present invention, the flow characteristics are improved, the amount of aldehyde generated during molding is small, the hue and transparency are excellent, there are no problems in terms of variation in transparency, crystallization speed and crystallization speed, and Provided is a polyester composition that gives a molded article having excellent mechanical properties such as pressure resistance when formed into a molded article. In addition, since the polyester composition of the present invention has improved flow characteristics, there is little distortion during molding, and a molded article having excellent heat-resistant dimensional stability, particularly a hollow molded article, can be efficiently produced by high-speed molding, and It provides a molded article having very good heat resistance. The polyester composition of the present invention can meet high quality requirements in the field of containers, sheets and the like.

Hereinafter, embodiments of the polyester, the polyamide, and the polyester composition of the present invention will be specifically described.
(polyester)
The polyester according to the present invention is a thermoplastic polyester mainly obtained from an aromatic dicarboxylic acid component and a glycol component, preferably a polyester containing 70 mol% or more of an aromatic dicarboxylic acid unit of the acid component, more preferably A polyester containing 85 mol% or more of an aromatic dicarboxylic acid unit, particularly preferably a polyester containing 95 mol% or more of an aromatic dicarboxylic acid unit of an acid component.

The aromatic dicarboxylic acid component constituting the polyester according to the present invention includes aromatic dicarboxylic acids such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like. And functional derivatives.
Examples of the glycol component constituting the polyester according to the present invention include aliphatic glycols such as ethylene glycol, 1,3-trimethylene glycol and tetramethylene glycol, and alicyclic glycols such as cyclohexanedimethanol.

Examples of the dicarboxylic acid used as a copolymerization component when the polyester is a copolymer include isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, Aromatic dicarboxylic acids such as 4,4′-diphenyl ether dicarboxylic acid, 4,4′-diphenyl ketone dicarboxylic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipine Aliphatic dicarboxylic acids such as acid, sebacic acid, succinic acid, glutaric acid and dimer acid and their functional derivatives, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid and their functional derivatives Etc.

  The glycol as a copolymerization component used when the polyester is a copolymer is diethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene. Glycols, 2-ethyl-2-butyl-1,3-propanediol, aliphatic glycols such as neopentyl glycol, dimer glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol 1,4-cyclohexane dimethylol, 2,5-norbornane dimethylol and other alicyclic glycols, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-β-hydroxyethoxy) Aromatic glycols such as phenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and alkylene oxide adducts of bisphenol A, polyalkylene glycols such as polyethylene glycol and polybutylene glycol Etc.

Furthermore, examples of the polyfunctional compound as a copolymer component used when the polyester is a copolymer include trimellitic acid, pyromellitic acid, and the like as an acid component, and glycerin and pentane as glycol components. Mention may be made of erythritol. The amount of copolymerization component used should be such that the polyester remains substantially linear. Monofunctional compounds such as benzoic acid and naphthoic acid may be copolymerized.

A preferred example of the polyester according to the present invention is a polyester whose main structural unit is composed of ethylene terephthalate, more preferably 70 mol% or more of ethylene terephthalate units, and isophthalic acid, 1,4-cyclohexanedi, as a copolymerization component. A copolyester containing methanol or the like, particularly preferably a polyester containing 95 mol% or more of ethylene terephthalate units.
Examples of these polyesters include polyethylene terephthalate (hereinafter abbreviated as PET), poly (ethylene terephthalate-ethylene isophthalate) copolymer, poly (ethylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, poly ( Examples thereof include an ethylene terephthalate-dioxyethylene terephthalate) copolymer, a poly (ethylene terephthalate-1,3-propylene terephthalate) copolymer, and a poly (ethylene terephthalate-ethylene cyclohexylene dicarboxylate) copolymer.

In addition, another preferable example of the polyester according to the present invention is a polyester in which a main structural unit is composed of 1,3-propylene terephthalate, and more preferably a polyester including 70 mol% or more of 1,3-propylene terephthalate units. Particularly preferred are polyesters containing 95 mol% or more of 1,3-propylene terephthalate units.
Examples of these polyesters include polypropylene terephthalate (PTT), poly (1,3-propylene terephthalate-1,3-propylene isophthalate) copolymer, poly (1,3-propylene terephthalate-1,4-cyclohexanedimethylene). Terephthalate) copolymer and the like.

Further, other preferable examples of the polyester according to the present invention are polyesters in which the main structural unit is composed of butylene terephthalate, more preferably a copolyester containing 70 mol% or more of butylene terephthalate units, and particularly preferable. Is a polyester containing 95 mol% or more of butylene terephthalate units.
Examples of these polyesters include polybutylene terephthalate (PBT), poly (butylene terephthalate-butylene isophthalate) copolymer, poly (butylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, poly (butylene terephthalate- 1,3-propylene terephthalate) copolymer, poly (butylene terephthalate-butylene cyclohexylene dicarboxylate) copolymer, and the like.

In addition, another preferred example of the polyester according to the present invention is a thermoplastic polyester whose main structural unit is composed of ethylene-2,6-naphthalate, and more preferably 70 mol% of ethylene-2,6-naphthalate units. The thermoplastic polyester containing the above is preferable, and a thermoplastic polyester containing 90 mol% or more of ethylene-2,6-naphthalate units is particularly preferable.
Examples of these thermoplastic polyesters include polyethylene-2,6-naphthalate (PEN), poly (ethylene-2,6-naphthalate-ethylene terephthalate) copolymer, poly (ethylene-2,6-naphthalate-ethylene isophthalate). ) Copolymer, poly (ethylene-2,6-naphthalate-dioxyethylene-2,6-naphthalate) copolymer, and the like.

Furthermore, another preferred example of the polyester according to the present invention is a polyester in which the main structural unit is composed of 1,4-cyclohexanedimethylene terephthalate, and more preferably 70 moles of 1,4-cyclohexanedimethylene terephthalate unit. %, Particularly preferably a polyester containing 90 mol% or more of 1,4-cyclohexanedimethylene terephthalate units.
Examples of these thermoplastic polyesters include poly-1,4-cyclohexanedimethylene terephthalate (PCT), poly (1,4-cyclohexanedimethylene terephthalate-ethylene terephthalate) copolymer, and the like.

  Further, the polyester A and the polyester B according to the present invention are linear polyesters containing 85 mol% or more of ethylene terephthalate units, preferably 90 mol% or more, more preferably 95 mol% or more, particularly preferably 97 mol% or more. Including linear polyester.

  The polyester according to the present invention can basically be produced by a conventionally known melt polycondensation method or melt polycondensation method-solid phase polymerization method. The melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. These may be comprised from a batch-type reaction apparatus, and may be comprised from the continuous-type reaction apparatus. The melt polycondensation step and the solid phase polymerization step may be operated continuously or may be operated separately. Hereinafter, an example of a preferable continuous production method for the polyester composition of the present invention will be described using polyethylene terephthalate (PET) as an example, but the present invention is not limited thereto. That is, a direct esterification method in which terephthalic acid is directly reacted with ethylene glycol and, if necessary, other copolymerization components to distill off water and esterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst, or , Produced by a transesterification method in which dimethyl terephthalate, ethylene glycol, and other copolymerization components as required are reacted to distill off methyl alcohol and transesterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst. Is done. Then, when the intrinsic viscosity is increased or the low acetaldehyde content or the low cyclic trimer content is used, such as a heat-resistant container for low flavor beverages or a film for inner surfaces of metal cans for beverages. The resulting melt polycondensed polyester is subsequently subjected to solid state polymerization.

  First, when a low polymer is produced by an esterification reaction, 1.02 to 2.0 mol, preferably 1.03 to 1.4 mol of ethylene glycol is added to 1 mol of terephthalic acid or an ester derivative thereof. The contained slurry is prepared and continuously supplied to the esterification reaction step.

In the esterification reaction, water or alcohol produced by the reaction is removed out of the system by a rectification column under conditions where ethylene glycol is refluxed using a multistage apparatus in which at least two esterification reactors are connected in series. While implementing. The temperature of the first stage esterification reaction is 240 to 270 ° C., preferably 245 to 265 ° C., and the pressure is 0.2 to 3 kg / cm ² G, preferably 0.5 to ² kg / cm ² G. The temperature of the esterification reaction in the final stage is usually 250 to 280 ° C, preferably 255 to 275 ° C, and the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.3 kg / cm ² G. . When carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stage are conditions between the reaction conditions for the first stage and the reaction conditions for the final stage. The increase in the reaction rate of these esterification reactions is preferably distributed smoothly at each stage. Ultimately, it is desirable that the esterification reaction rate reaches 90% or more, preferably 93% or more. By these esterification reactions, low-order condensates having a molecular weight of about 500 to 5,000 are obtained.
When terephthalic acid is used as a raw material, the esterification reaction can be carried out without a catalyst by the catalytic action of terephthalic acid as an acid, but may be carried out in the presence of a polycondensation catalyst.

  Also, tertiary amines such as triethylamine, tri-n-butylamine, benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, and lithium carbonate When a small amount of a basic compound such as sodium carbonate, potassium carbonate or sodium acetate is added, the proportion of dioxyethylene terephthalate component units in the main chain of polyethylene terephthalate is relatively low (5% relative to all diol components). Mol% or less).

  Next, in the case of producing a low polymer by transesterification, 1.1 to 2.0 mol, preferably 1.2 to 1.5 mol of ethylene glycol was contained with respect to 1 mol of dimethyl terephthalate. The solution is prepared and continuously fed to the transesterification step.

  The transesterification reaction is carried out while removing methanol generated by the reaction outside the system using a rectification column under the condition that ethylene glycol is distilled back using an apparatus in which 1 to 2 transesterification reactors are connected in series. To do. The temperature of the first stage transesterification is 180 to 250 ° C, preferably 200 to 240 ° C. The temperature of the transesterification reaction in the final stage is usually 230 to 270 ° C., preferably 240 to 265 ° C., and as the transesterification catalyst, fatty acid salts such as Zn, Cd, Mg, Mn, Co, Ca, Ba, carbonates Alternatively, Pb, Zn, Sb, Ge oxide or the like is used. A low-order condensate having a molecular weight of about 200 to 500 is obtained by these transesterification reactions.

  Dimethyl terephthalate, terephthalic acid or ethylene glycol, which is the starting material, includes virgin dimethyl terephthalate derived from para-xylene, ethylene glycol derived from terephthalic acid or ethylene, as well as methanol decomposition from used PET bottles. A recovered raw material such as dimethyl terephthalate, terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered by a chemical recycling method such as decomposition of ethylene glycol or ethylene glycol can also be used as at least part of the starting material. Needless to say, the quality of the recovered raw material must be refined to a purity and quality suitable for the intended use.

   Subsequently, the obtained low-order condensate is supplied to a multistage liquid phase condensation polymerization process. The polycondensation reaction conditions are as follows: the first stage polycondensation reaction temperature is 250 to 290 ° C., preferably 260 to 280 ° C., and the pressure is 500 to 20 Torr, preferably 200 to 30 Torr. The temperature is 265 to 300 ° C., preferably 275 to 295 ° C., and the pressure is 10 to 0.1 Torr, preferably 5 to 0.5 Torr. When carried out in three or more stages, the reaction conditions for the intermediate stage polycondensation reaction are conditions between the reaction conditions for the first stage and the reaction conditions for the last stage. The degree of increase in intrinsic viscosity achieved in each of these polycondensation reaction steps is preferably distributed smoothly. A single-stage polycondensation apparatus may be used for the polycondensation reaction.

  The polycondensation reaction is performed using a polycondensation catalyst. As the polycondensation catalyst, at least one compound selected from Ge, Sb, Ti, or Al compounds is preferably used. These compounds are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, ethylene glycol slurries and the like.

  Examples of the Ge compound include amorphous germanium dioxide, crystalline germanium dioxide powder or ethylene glycol slurry, a solution obtained by heating and dissolving crystalline germanium dioxide in water, or a solution obtained by adding ethylene glycol to this and heat treatment. In particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is dissolved by heating in water, or a solution in which ethylene glycol is added and heated. In addition, compounds such as germanium tetroxide, germanium hydroxide, germanium oxalate, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite can also be used. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used, the amount used is preferably 10 to 150 ppm, more preferably 13 to 100 ppm, still more preferably 13 to 50 ppm, and most preferably 15 to 45 ppm as the residual amount of Ge in the polyester.

  Examples of Ti compounds include tetraalkyl titanates such as tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate, tetra-n-butyl titanate, and partial hydrolysates thereof, titanium acetate, titanyl oxalate, titanyl oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl oxalate compounds such as titanium strontium oxalate, titanium trimellitate, titanium sulfate, titanium chloride, titanium halide hydrolyzate, titanium oxalate, titanium fluoride, titanium hexafluoride Titanium with potassium acid, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium acetylacetonate, hydroxy polyvalent carboxylic acid or nitrogen-containing polyvalent carboxylic acid A phosphorus compound is reacted with a complex compound, a composite oxide composed of titanium and silicon or zirconium, a reaction product of titanium alkoxide and a phosphorus compound, or a reaction product of titanium alkoxide and an aromatic polycarboxylic acid or its anhydride. The reaction product obtained by the above. The Ti compound is added so that the amount of Ti remaining in the produced polymer is 0.1 to 50 ppm, preferably 0.5 to 10 ppm.

  Examples of the Sb compound include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony. The Sb compound is added so that the residual amount of Sb in the produced polymer is in the range of 50 to 300 ppm, preferably 50 to 250 ppm, preferably 50 to 200 ppm, and more preferably 50 to 180 ppm.

  Al compounds include aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum carbonate, aluminum phosphate, aluminum phosphonate and other inorganic acid salts, aluminum n-propoxide, aluminum iso-propoxide Aluminum alkoxides such as aluminum n-butoxide and aluminum t-butoxide, aluminum chelate compounds such as aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, trimethylaluminum, triethylaluminum, etc. Organic aluminum compounds and partial hydrolysates thereof, aluminum oxide, etc. It is. Of these, aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the residual amount of Al in the produced polymer is in the range of 5 to 200 ppm, preferably 10 to 50 ppm.

  In the production of the polyester according to the present invention, an alkali metal compound or an alkaline earth metal compound may be used in combination as necessary. The alkali metal or alkaline earth metal is preferably at least one selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba, and the use of an alkali metal or a compound thereof is preferable. More preferred. When using an alkali metal or a compound thereof, use of Li, Na, K is particularly preferable. Examples of the alkali metal and alkaline earth metal compounds include saturated aliphatic carboxylates such as formic acid, acetic acid, propionic acid, butyric acid, and succinic acid, and unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid. , Aromatic carboxylates such as benzoic acid, halogen-containing carboxylates such as trichloroacetic acid, hydroxycarboxylates such as lactic acid, citric acid and salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, phosphorus Inorganic acid salts such as acid hydrogen, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid and bromic acid, and organic sulfonates such as 1-propanesulfonic acid, 1-pentanesulfonic acid and naphthalenesulfonic acid , Organic sulfates such as lauryl sulfate, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butyl Alkoxides such as alkoxy, chelate compounds and the like acetylacetonate, hydrides, oxides, and hydroxides and the like.

  The alkali metal compound or alkaline earth metal compound is added to the reaction system as a powder, an aqueous solution, an ethylene glycol solution, or the like. The alkali metal compound or alkaline earth metal compound is added so that the residual amount of these elements in the produced polymer is in the range of 1 to 50 ppm.

  Furthermore, the polyester according to the present invention is at least one selected from the group consisting of silicon, manganese, iron, cobalt, zinc, gallium, strontium, zirconium, niobium, molybdenum, indium, tin, hafnium, thallium, tungsten. You may contain the metal compound containing an element. These metal compounds include saturated aliphatic carboxylates such as acetates of these elements, unsaturated aliphatic carboxylates such as acrylates, aromatic carboxylates such as benzoic acid, and halogens such as trichloroacetic acid. Hydroxycarboxylates such as carboxylates and lactates, inorganic acid salts such as carbonates, organic sulfonates such as 1-propanesulfonate, organic sulfates such as lauryl sulfate, oxides, hydroxides, chlorides Products, alkoxides, acetylacetonates, and the like, and are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, ethylene glycol slurries, and the like. These metal compounds are added so that the residual amount of elements of these metal compounds per 1 ton of produced polymer is in the range of 0.05 to 3.0 mol. These metal compounds can be added at any stage of the polyester formation reaction step.

  Also, as stabilizers, phosphoric acid, phosphoric acid esters such as polyphosphoric acid and trimethyl phosphate, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, phosphine compounds It is preferable to use at least one phosphorus compound selected from the group consisting of: Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, Phosphoric acid, phosphorous acid trimethyl ester, phosphorous acid triethyl ester, phosphorous acid tributyl ester, methylphosphonic acid, methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phenylphosphonic acid Diphenyl ester and the like. These stabilizers can be added during the esterification reaction step from a slurry preparation tank of terephthalic acid and ethylene glycol. The P compound is added so that the residual amount of P in the produced polymer is preferably in the range of 5 to 100 ppm.

  When an Al compound is used as the polycondensation catalyst, it is preferably used in combination with a phosphorus compound, and is preferably used as a solution or slurry in which an aluminum compound and a phosphorus compound are previously mixed in a solvent. In the case of an Al compound, a more preferable phosphorus compound is at least one selected from the group consisting of phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds. It is a phosphorus compound. By using these phosphorus compounds, an effect of improving the catalytic activity is seen, and an effect of improving physical properties such as thermal stability of the polyester is seen. Among these, use of a phosphonic acid compound is preferable because of its great effect of improving physical properties and improving catalytic activity. Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  The melt polycondensation polyester obtained as described above is, for example, a method in which the melt polyester is extruded into water from the die pores after completion of the melt polycondensation and cut in water, or after the melt polycondensation is finished in the air from the die pores. After being extruded into strands, the chips are formed by a method of forming chips while cooling with cooling water.

  Next, the previous melt polycondensed polyester chip is preferably pre-crystallized in a continuous crystallization apparatus having two or more stages in an inert gas atmosphere. For example, in the case of PET, the temperature of 100 to 180 ° C. is 1 minute to 5 hours in the first stage precrystallization, and then the temperature of 160 to 210 ° C. is 1 minute to 3 hours in the second stage precrystallization. In the pre-crystallization of the second and higher stages, it is preferable to perform crystallization step by step at a temperature of 180 to 210 ° C. for 1 minute to 3 hours. The crystallinity of the chip after crystallization is preferably in the range of 30 to 65%, preferably 35 to 63%, and more preferably 40 to 60%. The crystallinity can be obtained from the density of the chip.

  Next, solid phase polymerization is carried out in an inert gas atmosphere or under reduced pressure at an optimum temperature for the prepolymer so that the increase in intrinsic viscosity due to solid phase polymerization is 0.10 deciliter / gram or more. For example, in the case of PET, the upper limit of the solid phase polymerization temperature is preferably 215 ° C. or lower, more preferably 210 ° C. or lower, particularly 208 ° C. or lower, and the lower limit is 190 ° C. or higher, preferably 195 ° C. or higher. is there.

  It is preferable to set the chip temperature to about 70 ° C. or less, preferably 60 ° C. or less, more preferably 50 ° C. or less within about 30 minutes, preferably within 20 minutes, more preferably within 10 minutes after completion of the solid phase polymerization.

  Polyesters such as polyester A and polyester B according to the present invention can be produced by appropriately controlling the type and amount of polycondensation catalyst, melt polycondensation, solid phase polymerization conditions, and the like. It can also be obtained by a method of giving an impact to the polyester chip thus obtained, and a method of blending a polyolefin resin, particularly polyethylene, polyoxymethylene resin, etc. as described below.

  The shape of the polyester chip according to the present invention may be any of a cylinder shape, a square shape, a spherical shape, a flat plate shape, and the like. The average particle diameter is usually 1.0 to 4 mm, preferably 1.0 to 3.5 mm, and more preferably 1.0 to 3.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.0 to 4 mm and the diameter is about 1.0 to 4 mm. In the case of spherical particles, it is practical that the maximum particle size is 1.1 to 2.0 times the average particle size and the minimum particle size is 0.7 times or more the average particle size. The weight of the chip is practically in the range of 5 to 40 mg / piece. In addition, when it is necessary to improve the solid-phase polymerization rate or to reduce the content of aldehydes more effectively, the average weight of the chips is preferably 1 to 5 mg / piece.

Further, the content of the cyclic ester oligomer of the polyester according to the present invention is 70% or less, preferably 60% or less, more preferably 50% of the content of the cyclic ester oligomer contained in the melt polycondensation polyester prepolymer of the polyester. Hereinafter, it is particularly preferably 35% or less. Here, the polyester generally contains cyclic ester oligomers having various degrees of polymerization, but the cyclic ester oligomer referred to in the present invention is the cyclic ester oligomer having the highest content among the cyclic ester oligomers contained in the polyester. An ester oligomer means, for example, a cyclic trimer in the case of a polyester having ethylene terephthalate as a main repeating unit.
In the case of PET, in which the polyester is a representative polyester having ethylene terephthalate as a main constituent unit, the content of the cyclic trimer of the melt polycondensed polyester prepolymer is about 1.0% by weight, and therefore the present invention is concerned. The content of the polyester cyclic trimer is 0.70% by weight or less, preferably 0.60% by weight or less, more preferably 0.50% by weight or less, and particularly preferably 0.35% by weight or less. preferable. The lower limit of the cyclic trimer content is 0.20% by weight or more, preferably 0.25% by weight or more, and more preferably 0.30% by weight or more from the viewpoint of economical production.

  The polyester composition of the present invention in which the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less is a polycondensation catalyst remaining in at least one of the constituting polyesters Can be produced by deactivation treatment.

  Examples of the method of deactivating the polyester polycondensation catalyst include a method of contacting the polyester chip with water, water vapor or water vapor-containing gas.

  Examples of the hydrothermal treatment method include at least one kind of polyester constituting the polyester composition, or a method in which a polyester composition containing these as a main component is immersed in water, or a method in which water is applied to these chips in a shower. Can be mentioned. The treatment time is 5 minutes to 2 days, preferably 10 minutes to 1 day, more preferably 30 minutes to 10 hours, and the water temperature is 20 to 180 ° C., preferably 40 to 150 ° C., more preferably 50 to 120 ° C.

  When the polyester chip is contacted with water vapor or water vapor containing gas, the water vapor or water vapor containing gas or water containing air at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C., is preferably used per 1 kg of the granular polyester. The water vapor is supplied as water vapor in an amount of 0.5 g or more, or is present to bring the granular polyester into contact with water vapor. The contact between the polyester chip and water vapor is usually performed for 10 minutes to 2 days, preferably 20 minutes to 10 hours. The processing method may be either a continuous method or a batch method.

Further, as another means for deactivating the polycondensation catalyst, there is a method in which a phosphorus compound is blended with the polyester and mixed and reacted in a molten state such as during molding to deactivate the polycondensation catalyst.
As a method of blending a phosphorous compound with polyester, a predetermined amount of phosphorous compound is polyester by a method of dry blending the phosphorous compound with the polyester or a method of mixing a polyester masterbatch chip in which a phosphorous compound is melt-kneaded and blended with a polyester chip. And a method of inactivating the polycondensation catalyst by melting in an extruder or a molding machine, a method of immersing chips in a phosphorus compound solution, particularly a phosphoric acid aqueous solution, and a method of adding as a master batch. These phosphorus compounds may be copolymerized with polyester.

  Examples of the phosphorus compound used include phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. Specific examples thereof are the compounds described above, and these may be used alone or in combination of two or more.

  A mixture of the polyester A and the polyester B according to the present invention can be obtained by mixing the polyester A and the polyester B by a conventionally known method. For example, the above polyester A and the above polyester B are dry blended with a tumbler, V-type blender, Henschel mixer, etc., and the dry blended mixture is melted once or more with a single screw extruder, twin screw extruder, kneader or the like. The method of mixing etc. is mentioned. Polyamide can be blended with the polyester mixture thus obtained.

  There is also a method of simultaneously mixing polyester A, polyester B and polyamide as described below.

When a polyester mixture according to the polyester composition of the present invention is to be obtained by dry blending a polyester A chip and a polyester B chip by the above-described method, if the variation of the mixing ratio of both is large, the polyester composition Variations in the intrinsic viscosity and crystallization characteristics of the molded article made of the product occur, and the characteristics such as acetaldehyde content, transparency, and thickness of the obtained molded article fluctuate and become a big problem. In addition, when the polyester composition after dry blending is supplied to a dryer or a molding machine, or discharged from these devices, or when the polyester composition is transferred in a transfer pipe with a gas, etc. When moving the polyester, the blending ratio of polyester A or polyester B may vary. The variation factors include the difference in true density and bulk density between the two chips. The true density is mainly determined by the difference in the solid-state polymerization conditions such as the solid-phase polymerization temperature and time. It depends on the shape of the chip (the state of the cut end) and the amount of fine powder (also called fine) or fine particles.
The density of the polyester A chip and the polyester B chip according to the present invention is 1.370 grams / cubic centimeter or more, preferably 1.380 grams / cubic centimeter or more, more preferably 1.390 grams / cubic centimeter or more, particularly preferably 1. Desirably 395 grams / cubic centimeter or more. Further, if it is attempted to obtain a chip having a density of 1.415 g / cubic centimeter or more, there is a problem in that chip fusion occurs during solid phase polymerization. When the density of the chip is less than 1.390 grams / cubic centimeter, the content of the cyclic trimer cannot be reduced to 0.7% by weight or less, and problems such as mold contamination occur. In the case of a certain heat resistant molded body, it is not preferable.

  The difference in density between the polyester A chip and the polyester B chip according to the present invention is within 0.025 gram / cubic centimeter, preferably within 0.02 gram / cubic centimeter, and more preferably within 0.01 gram / cubic centimeter. When the difference in density exceeds 0.025 grams / cubic centimeter, when the molded product is produced from the polyester, the variation of the compounding ratio in the time series direction becomes large, so that the intrinsic viscosity and crystallization characteristics of the molded product are increased. This causes a problem that a molded product having large thickness spots, stretch spots, and transparent spots is generated.

  In addition, since the majority of fines are usually more highly crystallized than the chip, the fines contained in the high-density polyester chip remain as an unmelted or incomplete melt at the time of molding, and these are stretch molded articles. In particular, there is a possibility that a whitened product or a wrinkled product is formed in a thick stretched molded product. When the density difference between the chips exceeds 0.025 grams / cubic centimeter, the occurrence of these whitened matters becomes remarkable and the commercial value is lost. Further, in the case of a polyester composition in which the density difference between the two is within 0.01 gram / cubic centimeter, the effect does not appear and it is meaningless.

  The chip sizes of polyester A and polyester B according to the present invention are as described above. Among them, a suitable chip has a bulk density of 0.80 to 0.97 grams / cubic centimeter, preferably 0.82. To 0.96 grams / cubic centimeter, particularly preferably 0.83 to 0.95 grams / cubic centimeter. When the bulk density is less than 0.80 grams / cubic centimeter, the flowability of the chips in the molding machine is poor and the mixing of the two becomes insufficient. Producing chips exceeding 0.97 grams / cubic centimeter is wasteful from an economic point of view. The difference in bulk density between the two is within 0.10 gram / cubic centimeter, preferably within 0.08 gram / cubic centimeter, more preferably within 0.05 gram / cubic centimeter, and particularly preferably within 0.03 gram / cubic centimeter. . When the difference in bulk density exceeds 0.10 gram / cubic centimeter, when the molded product is produced from the polyester composition, the variation of the blending ratio in the time-series direction becomes large. As a result, fluctuations in the crystallization characteristics occur, resulting in a molded product having large thickness spots, stretch spots, and transparent spots. The effect is not clear when the density difference between the two is within 0.01 gram / cubic centimeter.

The fine content of the polyester constituting the polyester composition of the present invention is preferably 0.1 to 5000 ppm. The fine content is preferably 0.1 to 3000 ppm, more preferably 0.1 to 1000 ppm, further preferably 0.1 to 500 ppm, and most preferably 0.1 to 100 ppm. When it exceeds 5000 ppm, the bulk density is less than 0.80 grams / cubic centimeter, which is not preferable.
In addition, the fine melting point of the polyester according to the present invention is 265 ° C. or less, preferably 263 ° C. or less, more preferably 260 ° C. or less. In the case of containing fine particles having a melting point exceeding 265 ° C., the crystals are not completely melted under the usual melt molding conditions and remain as crystal nuclei. When the hollow molded body plug portion is heated, the crystallization speed is increased, so that the crystallization of the plug portion becomes excessive. As a result, since the amount of shrinkage of the plug portion does not fall within the specified value range, the capping portion of the plug portion becomes defective and the contents may leak. In addition, the preform for hollow molding is whitened, so that normal stretching is impossible, thickness unevenness occurs, the crystallization speed is high, and the transparency of the obtained hollow molded body is deteriorated. Fluctuations also become large. Further, since the obtained sheet-like material is poor in transparency and has a high crystallization rate, normal stretching is impossible, and only a stretched film having large thickness spots and poor transparency can be obtained.

  The melting point of the fine is measured by the following method using a differential scanning calorimeter (DSC), and the melting peak temperature representing the melting point of the fine is one or more melting peaks. In the present invention, when there is one melting peak, the peak temperature is indicated, and when there are a plurality of melting peaks, the highest temperature among the plurality of melting peaks is indicated. The melting peak temperature is referred to as “the highest peak temperature of the fine melting peak temperature”, and is referred to as “fine melting point” in the examples.

  However, when trying to obtain a hollow molding preform or sheet having good transparency and stretchability from a polyester composition containing fines having a melting peak temperature exceeding 265 ° C., 300 ° C. It must be melt molded at these high temperatures. However, at such a high temperature of 300 ° C. or higher, the thermal decomposition of the polyester becomes severe, and a large amount of by-products such as acetaldehyde and formaldehyde are generated. As a result, the flavor of the contents such as molded articles is great. It will have an effect.

  In addition, the polyester composition of the present invention contains polyamide, and when it contains at least one resin selected from the group consisting of the following polyolefin resins and polyacetal resins, these resins are generally present. Since the thermal stability is often inferior to that of the polyester according to the invention, in the molding at a high temperature of 300 ° C. or higher as described above, a large amount of by-products are generated due to thermal decomposition. It will have a greater effect on the flavor of the contents.

  In addition, the content of aldehydes such as acetaldehyde in the polyester according to the present invention is 50 ppm or less, preferably 30 ppm or less, more preferably 10 ppm or less. When the aldehyde content exceeds 50 ppm, the effect of maintaining the flavor of contents such as a molded article molded from the polyester composition is deteriorated. Further, these lower limits are preferably 0.1 ppb from the viewpoint of production. Here, the aldehydes are acetaldehyde when the polyester is a polyester having ethylene terephthalate as a main constituent unit, and allylaldehyde in the case of a polyester having 1,3-propylene terephthalate as a main constituent unit. It is. In particular, when the polyester having ethylene terephthalate as the main repeating unit as the polyester composition of the present invention is used as a material for containers for low flavor beverages such as mineral water, the acetaldehyde of each of the above polyesters The content is desirably 10 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, and most preferably 4 ppm or less.

  The formaldehyde content of the polyester according to the present invention is 20 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less. When the formaldehyde content is 20 ppm or more, the flavor and odor of contents such as a container molded from the polyester composition are deteriorated. In particular, when the polyester composition of the present invention is used as a material for containers for low flavor beverages such as mineral water, the formaldehyde content of the polyester is preferably 3 ppm or less, more preferably 2 ppm or less. Is desirable.

The content of dialkylene glycol copolymerized in the polyester according to the present invention is preferably 0.5 to 7.0 mol%, more preferably 1.0 to 6% of the glycol component constituting the polyester. It is 0.0 mol%, More preferably, it is 1.0-5.0 mol%. When the amount of dialkylene glycol exceeds 7.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large during molding, and the increase in the content of aldehydes is unfavorable. Further, in order to produce a polyester having a dialkylene glycol content of less than 0.5 mol%, it is necessary to select uneconomical production conditions as transesterification conditions, esterification conditions or polymerization conditions. Do not fit. Here, the dialkylene glycol copolymerized in the polyester, for example, in the case of a polyester whose main structural unit is ethylene terephthalate, is a diethylene glycol by-produced during production from ethylene glycol, which is a glycol. Among them, diethylene glycol (hereinafter abbreviated as DEG) copolymerized with the polyester, and in the case of a polyester having 1,3-propylene terephthalate as a main constituent unit, is glycol 1 Of di (1,3-propylene glycol) (or bis (3-hydroxypropyl) ether) by-produced from 1,3-propylene glycol during production, di (1,3-propylene) copolymerized with the polyester Glycol (hereinafter referred to as DPG).

  In addition, the amount of diethylene glycol copolymerized with the polyester according to the present invention, particularly the polyester in which the main repeating unit is composed of ethylene terephthalate is 0.5 to 7.0 of the glycol component constituting the polyester. Mol%, more preferably 1.0-6.0 mol%, still more preferably 1.5-5.0 mol%, particularly preferably 2.0-3.0 mol%, most preferably 2.0-2. .9 mol%. When the amount of diethylene glycol exceeds 7.0 mol%, the thermal stability is deteriorated, the molecular weight is greatly reduced during molding, and the increase in acetaldehyde content and formaldehyde content is large, which is not preferable. Further, in order to produce a polyester having a diethylene glycol content of less than 0.5 mol%, it is necessary to select non-economic production conditions as transesterification conditions, esterification conditions or polymerization conditions, and the cost does not match. In addition, there is a problem that the transparency of the obtained molded article is deteriorated.

(polyamide)
The polyamide according to the present invention is at least one polyamide selected from aliphatic polyamides and partially aromatic polyamides.
As the aliphatic polyamide, one or more kinds selected from known aliphatic polyamides are used. Specific examples of such aliphatic polyamides include butyrolactam, δ-valerolactam, enantolactam, ε-caprolactam, ω-laurolactam and other ring-opening polymers of lactam, 6-aminocaproic acid, 11-aminoundecanoic acid, 12 Examples include polymers of aminocarboxylic acids such as aminododecanoic acid, condensation polymers of diamines and dicarboxylic acids, and copolymers thereof. Examples of diamines include hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4-trimethylhexamethylene diamine, 2,4,4- Examples include aliphatic diamines such as trimethylhexamethylenediamine, and alicyclic diamines such as 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, and bis (p-aminocyclohexyl) methane. Dicarboxylic acids include aliphatic dicarboxylic acids such as adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecanoic acid, undecadioic acid, dodecanedioic acid, and dimer acid. Acid, 1,4-cycl Alicyclic dicarboxylic acids such as hexane dicarboxylic acid.

  Specific examples of the aliphatic polyamide include nylon 4, nylon 6, nylon 7, nylon 8, nylon 9, nylon 11, nylon 12, nylon 6,6, nylon 6,9, nylon 6,10, nylon 6, 11, nylon 6,12, nylon 6T, nylon 6I, nylon MXD6, nylon 6 / 6,6, nylon 6 / 6,10, nylon 6/12, nylon 6 / 6T, nylon 6I / 6T and the like.

  The partially aromatic polyamide according to the present invention is mainly composed of a polyamide having a unit derived from an aliphatic dicarboxylic acid and an aromatic diamine as a main structural unit, or a unit derived from an aromatic dicarboxylic acid and an aliphatic diamine. Polyamide as a unit.

  The aromatic dicarboxylic acid component constituting the partially aromatic polyamide according to the present invention includes terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, Examples include diphenoxyethanedicarboxylic acid and functional derivatives thereof.

  As the aliphatic dicarboxylic acid component constituting the partially aromatic polyamide according to the present invention, a linear aliphatic dicarboxylic acid is preferable, and a linear aliphatic dicarboxylic acid having an alkylene group having 4 to 12 carbon atoms is particularly preferable. preferable. Examples of such linear aliphatic dicarboxylic acids include adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, spellic acid, azelaic acid, undecanoic acid, undecadioic acid, dodecanedioic acid , Dimer acids and functional derivatives thereof.

  Examples of the aromatic diamine component constituting the partially aromatic polyamide according to the present invention include metaxylylenediamine, paraxylylenediamine, and para-bis- (2-aminoethyl) benzene.

  The aliphatic diamine component constituting the partially aromatic polyamide according to the present invention is an aliphatic diamine having 2 to 12 carbon atoms or a functional derivative thereof. The aliphatic diamine may be a linear aliphatic diamine or a branched chain aliphatic diamine. Specific examples of such linear aliphatic diamines include ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, Examples include aliphatic diamines such as nonamethylenediamine, decamethylenediamine, undecamethylenediamine, and dodecamethylenediamine.

  Moreover, as a dicarboxylic acid component which comprises the partial aromatic polyamide which concerns on this invention, alicyclic dicarboxylic acid can also be used other than the above aromatic dicarboxylic acid and aliphatic dicarboxylic acid. Examples of the alicyclic dicarboxylic acid include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid.

  Moreover, as a diamine component which comprises the partial aromatic polyamide which concerns on this invention, an alicyclic diamine other than the above aromatic diamine and an aliphatic diamine can also be used. Examples of the alicyclic diamine include alicyclic diamines such as cyclohexanediamine and bis- (4,4′-aminohexyl) methane.

  In addition to the diamine and dicarboxylic acid, lactams such as ε-caprolactam and laurolactam, aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid, aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid, etc. It can be used as a copolymerization component. In particular, the use of ε-caprolactam is desirable.

  Preferred examples of the partially aromatic polyamide according to the present invention are derived from metaxylylenediamine or mixed xylylenediamine containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine and an aliphatic dicarboxylic acid. A metaxylylene group-containing polyamide containing at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more in the molecular chain.

  The partially aromatic polyamide according to the present invention may contain a structural unit derived from a polybasic carboxylic acid having 3 or more bases such as trimellitic acid and pyromellitic acid within a substantially linear range. Good.

  Examples of these polyamides include homopolymers such as polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylylene speramide, and metaxylylenediamine / adipic acid / isophthalic acid copolymers, metaxylylene. / Paraxylylene adipamide copolymer, metaxylylene / paraxylylene piperamide copolymer, metaxylylene / paraxylylene azelamide copolymer, metaxylylenediamine / adipic acid / isophthalic acid / ε-caprolactam copolymer And metaxylylenediamine / adipic acid / isophthalic acid / ω-aminocaproic acid copolymer.

  In addition, other preferable examples of the partially aromatic polyamide according to the present invention include at least 20 mol% of a structural unit derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid in the molecular chain. More preferably, it is a polyamide containing 30 mol% or more, particularly preferably 40 mol% or more.

  Examples of these polyamides include polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, hexamethylene diamine / terephthalic acid / isophthalic acid copolymer, polynonamethylene terephthalamide, polynonamethylene isophthalamide, nonamethylene diamine / terephthalic acid. / Isophthalic acid copolymer, nonamethylenediamine / terephthalic acid / adipic acid copolymer, and the like.

  Other preferred examples of the partially aromatic polyamide according to the present invention include, in addition to at least one acid selected from aliphatic diamine and terephthalic acid or isophthalic acid, lactams such as ε-caprolactam and laurolactam, and aminocaproic acid. An aminocarboxylic acid such as aminoundecanoic acid, an aromatic aminocarboxylic acid such as para-aminomethylbenzoic acid or the like as a copolymerization component, and at least selected from an aliphatic diamine and terephthalic acid or isophthalic acid Polyamide containing at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more of a structural unit derived from one kind of acid in the molecular chain.

  Examples of these polyamides include hexamethylenediamine / terephthalic acid / ε-caprolactam copolymer, hexamethylenediamine / isophthalic acid / ε-caprolactam copolymer, hexamethylenediamine / terephthalic acid / adipic acid / ε-caprolactam copolymer Examples include coalescence.

  The aliphatic polyamide, for example, nylon 6, is ε-caprolactam and water, or, if necessary, a polymerization degree adjusting agent such as acetic acid, or the dicarboxylic acid or diamine that is a copolymerization component with ε-caprolactam and water. Is produced by reacting with a normal pressure polycondensation apparatus.

  The partially aromatic polyamide is heated in an aqueous solution of an aminocarboxylate salt formed from a diamine and a dicarboxylic acid under pressure and normal pressure, and polycondensation in a molten state while removing water and water generated by the polycondensation reaction. Or a method in which a diamine and a dicarboxylic acid are heated and subjected to polycondensation by direct reaction in a molten state under normal pressure or subsequently under vacuum.

Further, a polyamide having a higher viscosity can be obtained by solid-phase polymerization of the polyamide chip obtained by the melt polycondensation reaction.
The polycondensation reaction of the polyamide may be performed in a batch reactor or may be performed in a continuous reactor.

When the terminal amino group concentration (μmol / g) of the polyamide according to the present invention is AEG and the terminal carboxyl group concentration (μmol / g) of the polyamide is CEG, the polyamide according to the present invention has the following formulas (1) and ( It is preferable to satisfy all of 2).
2000 ≧ AEG + CEG ≧ 80 (1)
AEG / CEG ≧ 1.0 (2)

  A more preferable upper limit of AEG + CEG is 1500, a further preferable upper limit is 1000, and a particularly preferable upper limit is 500. A more preferred lower limit of AEG + CEG is 100, a more preferred lower limit is 130, and a particularly preferred lower limit is 150. When the total terminal group concentration (AEG + CEG) consisting of the terminal carboxyl group concentration and the terminal amino group concentration in the polyamide is less than 80 (μmol / g), the flavor retention of the hollow molded article obtained from the polyester composition of the present invention can be improved. As a beverage container for low flavor, it may be impractical and may cause problems. On the other hand, if the total end group concentration (AEG + CEG) exceeds 2,000, the molded product may become highly colored, which may be a problem.

Further, the end group concentration of the polyamide according to the present invention is represented by the following formula (2).
AEG / CEG ≧ 1.0 (2)
(In Formula (2), AEG represents the terminal amino group concentration (μmol / g) of the polyamide, and CEG represents the terminal carboxyl group concentration (μmol / g) of the polyamide.)
It is preferable that it is the range of these.

  When the ratio of the terminal amino group concentration to the terminal carboxyl group concentration in the polyamide (AEG / CEG) is less than 1.0, the flavor retention of the hollow molded article obtained from the polyester composition of the present invention becomes poor, As a container for a low flavor beverage, there are cases where it is poor in practicality, which is a problem. Further, when the ratio of the terminal amino group concentration to the terminal carboxyl group concentration in the polyamide (AEG / CEG) exceeds 20, the hollow molded body obtained from the polyester composition of the present invention becomes intensely colored and the commercial value is lost. Because there is a thing, it is not preferable.

  Such a polyamide according to the present invention can be produced by adjusting the concentration of terminal groups to a desired value by polycondensation by adding an excessive amount of diamine to dicarboxylic acid.

  In the production of the polyamide, it is preferable to polymerize by adding a phosphorus compound as a stabilizer for preventing gelation due to thermal degradation.

  When the phosphorus atom content derived from the phosphorus compound in the polyamide according to the present invention is X, it is desirable that 0 <X ≦ 500 ppm. The lower limit is preferably 0.1 ppm, more preferably 1 ppm, and even more preferably 5 pm. The upper limit is preferably 400 ppm, more preferably 300 ppm, and even more preferably 250 ppm. When X is 0, that is, when no phosphorus atom is contained, the effect of preventing gelation during polycondensation is inferior. On the other hand, if X is more than 500 ppm, the gelation preventing effect is limited and it is uneconomical.

  As the phosphorus compound added to the polyamide, it is preferable to use at least one selected from compounds represented by the following chemical formulas (A-1) to (A-4).

(Where R _{1 to} R ₇ are hydrogen, alkyl group, aryl group, cycloalkyl group or arylalkyl group, X _{1 to} X ₅ are hydrogen, alkyl group, aryl group, cycloalkyl group, arylalkyl group or alkali metal, Alternatively, _one of X _{1 to} X ₅ and R _{1 to} R ₇ in each formula may be linked to each other to form a ring structure)

または

の化合物およびこれらの加水分解物、ならびに上記ホスフィン酸化合物の縮合物などがある。 Examples of the phosphinic acid compound represented by the chemical formula (A-1) include dimethylphosphinic acid, phenylmethylphosphinic acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, hypochlorous acid. Ethyl phosphate,

Or

And hydrolysates thereof, and condensates of the above phosphinic acid compounds.

  Examples of the phosphonic acid compound represented by the chemical formula (A-2) include phenylphosphonic acid, ethylphosphonic acid, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, ethylphosphonic acid. Examples include potassium acid.

  Examples of the phosphonous acid compound represented by the chemical formula (A-3) include phenylphosphonous acid, sodium phenylphosphonite, potassium phenylphosphonite, lithium phenylphosphonite, and ethyl phenylphosphonite.

  Examples of the phosphorous acid compound represented by the chemical formula (A-4) include phosphorous acid, sodium hydrogen phosphite, sodium phosphite, triethyl phosphite, triphenyl phosphite, pyrophosphorous acid and the like. .

In the production of the polyamide according to the present invention, an alkali metal-containing compound represented by the following chemical formula (B) is added in order to further improve the thermal stability and further prevent gelation. The alkali metal atom content in the polyamide is preferably 1000 ppm or less, preferably 500 ppm or less, more preferably 200 ppm or less.
Z-OR ₈ (B)
(However, Z is an alkali metal, R ₈ is hydrogen, an alkyl group, an aryl group, a cycloalkyl group, -C (O) CH ₃ or -C (O) OZ ', ( Z' is hydrogen, an alkali metal))

  Examples of the alkali compound represented by the chemical formula (B) include sodium hydroxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, lithium methoxide, sodium acetate, sodium carbonate, and alkaline earth Examples include alkaline earth compounds containing metals, but they are not limited to these compounds.

The total alkali metal content in the polyamide according to the present invention (the total amount of the alkali metal atoms contained in the phosphorus stabilizer and the alkali metal atoms contained in the alkali metal compound) is in the polyamide. It is preferable that it is 1.0-6.0 times mole of content of a phosphorus atom. The lower limit is more preferably 1.5 times mol, still more preferably 2.0 times mol, particularly preferably 2.3 times mol, most preferably 2.5 times mol, and the upper limit is more preferably 5.5 times mol. Mol, more preferably 5.0 times mol. When the total alkali metal content is less than 1.0 times the phosphorus atom content, gelation is likely to be promoted. On the other hand, if the total alkali metal content is more than 6.0 times the phosphorus atom content, the polymerization rate will be slow, the viscosity will not increase sufficiently, and gelation will be promoted especially in the reduced pressure system, which is uneconomical. is there.
The compounds represented by the chemical formulas (A-1) to (A-4) and the chemical formula (B) used in the present invention may be used singly, but the polyester composition is more preferably used in combination. This is preferable because thermal stability is improved.

In order to mix the phosphorus compound or the alkali metal-containing compound with the polyamide used in the present invention, the raw material before polymerization of the polyamide, these may be added during the polymerization, or may be melt-mixed with the polymer.
Moreover, these compounds may be added simultaneously or separately.

The polyamide according to the present invention preferably has a second-order transition point of the polyamide measured by DSC (differential scanning calorimeter) of 50 to 120 ° C. When the secondary transition point is less than 50 ° C., it is not preferable because it is fused at the time of drying process or extrusion with polyester or cannot be quantitatively extruded. Moreover, when exceeding 120 degreeC, when extending | stretching a polyester composition, it will not be stretched | homogenized uniformly but a thickness spot etc. will arise and it is unpreferable.
A polyamide having a secondary transition point in the above range can be obtained by appropriately adjusting the type and ratio of diamine, dicarboxylic acid and the like as raw materials.

  The shape of the polyamide chip according to the present invention may be any of a cylinder shape, a square shape, a spherical shape, a flat plate shape, and the like. The average particle size is usually in the range of 1.0 to 5 mm, preferably 1.2 to 4.5 mm, more preferably 1.5 to 4.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.0 to 4 mm and the diameter is about 1.0 to 4 mm. In the case of spherical particles, it is practical that the maximum particle size is 1.1 to 2.0 times the average particle size and the minimum particle size is 0.7 times or more the average particle size. The average weight of the chip is practically in the range of 5 to 40 mg / piece. In addition, when it is necessary to improve the solid-phase polymerization rate or the drying rate, the average weight of the chips is preferably 1 to 5 mg / piece.

  In the polyester composition of the present invention, fluctuations in the blending amount of the polyamide cause problems such as fluctuations in the AA reduction effect, fluctuations in transparency, fluctuations in the crystallization speed, etc. This is very important.

In order not to cause such variation in the blending amount, it is important to reduce the fine content of the polyamide to 5% by weight or less, preferably 1% by weight or less, more preferably 0.5% by weight or less. When the fine content exceeds 5% by weight, when the polyester composition is produced by the following method, the fluctuation of the polyamide content in the polyester composition becomes large, which causes a problem. The lower limit is 0.1 ppm, and it is useless from the economical point of view.
Examples of the method for setting the fine content in the polyamide to 1% by weight or less include, for example, a method for controlling the cooling temperature of the polyamide at the time of chip formation, a method for chip formation using an underwater cutter, or a sieving step or an air flow. A method of passing through a fine removal step by, for example, can be employed.

  Similarly, in order not to cause blending of polyamide, the bulk density of the amide chip is 0.60 to 0.90 gram / cubic centimeter, preferably 0.70 to 0.88 gram / cubic centimeter, particularly preferably 0.8. Preferably it is 75-0.85 grams / cubic centimeter. When the bulk density is less than 0.60 grams / cubic centimeter, for example, the flowability of the chips in the molding machine is poor and the mixing of the polyamide becomes insufficient, resulting in fluctuations in performance such as flavor retention of the molded body. Producing chips exceeding 0.90 grams / cubic centimeter is wasteful from an economic point of view.

(Polyester composition)
The mixing ratio of the polyester and the polyamide constituting the polyester composition of the present invention is preferably 0.01 to 30 parts by weight of the polyamide with respect to 100 parts by weight of the polyester. The amount of polyamide added in the case where it is desired to obtain a molded article having a very low content of aldehydes and excellent flavor retention from the polyester composition, is preferably 0.01 to 100 parts by weight of the polyester. The lower limit is more preferably 0.1 parts by weight, still more preferably 0.5 parts by weight, and the upper limit is more preferably 4 parts by weight, still more preferably 3 parts by weight.

  In addition, when it is desired to obtain a molded article having excellent gas barrier properties, transparency that does not impair practicality, and a very low content of aldehydes and excellent flavor retention, 100 parts by weight of the polyester is used. On the other hand, it is preferably 1 to 30 parts by weight, the lower limit is more preferably 3 parts by weight, still more preferably 5 parts by weight, and the upper limit is more preferably 28 parts by weight, still more preferably 25 parts by weight.

  When the amount of polyamide blended is less than 0.01 parts by weight with respect to 100 parts by weight of polyester, the content of aldehydes such as AA in the obtained molded product is difficult to be reduced, and the flavor retention of the molded product content Can be very bad. Further, when the amount of the polyamide mixed exceeds 30 parts by weight with respect to 100 parts by weight of the polyester, the transparency of the obtained molded body tends to be very poor, and the mechanical properties of the molded body may be deteriorated. is there.

  The polyester composition of the present invention is obtained by adding a predetermined amount of polyamide at any reaction stage from the production of a low-polymerization degree oligomer of at least one of polyester A or polyester B to the production of a melt polycondensation polymer. Can be manufactured. For example, the polyamide may be added to a reactor such as an esterification reactor or a polycondensation reactor in an appropriate form such as a fine particle, powder, or melt, or the above-mentioned reactor may be added to the reactor in the next step. It can be obtained by introducing the polyamide or a mixture of the polyamide and the polyester in a molten state into a transport pipe for the reaction product of the polyester. Furthermore, it is also possible to obtain a chip obtained by solid phase polymerization under a high vacuum or an inert gas atmosphere if necessary.

  The polyester composition of the present invention can also be obtained by a method of mixing polyester A, polyester B and polyamide by a conventionally known method, or a method of mixing polyamide in a mixture of polyester A and polyester B. For example, polyamide chips, polyester A chips, and polyester B chips are dry blended with a tumbler, V-type blender, Henschel mixer, etc., and the dry blended mixture is once or more with a single screw extruder, twin screw extruder, kneader, etc. Examples thereof include those obtained by melt mixing, and those obtained by subjecting chips from the melt mixture to solid phase polymerization under a high vacuum or an inert gas atmosphere as necessary.

  Further, a method in which a solution obtained by dissolving the polyamide in a solvent such as hexafluoroisopropanol is attached to the surface of a polyester chip, and the polyester is collided with the member in a space where the polyamide member is present. Examples thereof include a method of attaching the polyamide to the surface of a polyester chip.

The formaldehyde content of the molded product obtained from the polyester composition of the present invention is 7 ppm or less, preferably 5 ppm or less, more preferably 3 ppm or less, and further preferably 2 ppm or less. When the formaldehyde content is 7 ppm or more, the flavor and odor of the contents such as a container molded from this polyester are deteriorated.
Here, the formaldehyde content of the molded body is the same as the acetaldehyde content, from a 2 mm thick plate of a stepped molded plate molded at 290 ° C. according to the molding method described in the following “Measurement Method” section. This is the value obtained for the sample.

  The content of the cyclic ester oligomer in the polyester composition of the present invention is preferably 0.60% by weight or less, more preferably 0.50% by weight or less, and particularly preferably 0.35% by weight or less. The lower limit of the cyclic ester oligomer is 0.20% by weight or more, preferably 0.22% by weight or more, and more preferably 0.25% by weight or more from the viewpoint of economical production. When molding a heat-resistant hollow molded article or the like from the polyester composition of the present invention, heat treatment is performed in a heating mold, but if the cyclic ester oligomer content is 0.70% by weight or more, heating is performed. The adhesion of the oligomer to the mold surface increases rapidly, and the transparency of the obtained hollow molded article is very deteriorated.

  Further, when the polyester composition of the present invention is melted for 60 minutes at a temperature of 290 ° C., a part of a molded product obtained by the molding method described in the following “Measurement method” section, It is preferably 0.3% by weight or less, more preferably 0.1% by weight or less. When the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes exceeds 0.40% by weight, free low molecules containing linear monomers and cyclic ester oligomers when the resin is melted when molding a molded article Since the compound content increases, the flavor retention of the contents of the molded body deteriorates, and the adhesion of the oligomer to the surface of the heating mold increases rapidly, and the transparency of the obtained hollow molded body and the like is extremely deteriorated. .

  Moreover, it is preferable that the polyester composition of this invention contains 0.1-5000 ppm of fine. The fine content is preferably 0.1 to 3000 ppm, more preferably 0.1 to 1000 ppm, further preferably 0.1 to 500 ppm, and most preferably 0.1 to 100 ppm. When the content of fine is less than 0.1 ppm, the crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded container becomes insufficient, so that the amount of shrinkage of the plug portion is within the specified range. In some cases, it cannot fit inside and cannot be capped. When the content exceeds 5000 ppm, the variation in blending amount and blending amount of the polyester A and the polyester B is likely to occur, and as a result, the intrinsic viscosity variation of the molded body becomes large, and the crystallization speed and stretchability vary. Arise. In the case of a sheet-like material, the transparency and the surface state are deteriorated, and the fluctuation of these characteristics is large. When this is stretched, the thickness unevenness is deteriorated. In addition, the degree of crystallinity of the plug part of the hollow molded body becomes excessive and fluctuates, and therefore the shrinkage amount of the plug part does not fall within the specified value range, resulting in poor capping of the plug part and leakage of contents. In addition, the preform for the hollow molded body is whitened, so that normal stretching is impossible. In particular, the fine content of the polyester composition for the hollow molded body is preferably 0.1 to 500 ppm.

  Furthermore, it is preferable that the polyester composition of the present invention contains 0.1 ppb to 50000 ppm of at least one resin selected from the group consisting of polyolefin resins and polyacetal resins. The blending ratio of the resin used in the present invention to the polyester is 0.1 ppb to 10000 ppm, preferably 0.3 ppb to 1000 ppm, more preferably 0.5 ppb to 100 ppm, still more preferably 1.0 ppb to 1 ppm, particularly preferably. 1.0 ppb to 45 ppb. When the blending amount is less than 0.1 ppb, the crystallization speed becomes very slow and the crystallization of the plug part of the hollow molded body becomes insufficient. Therefore, if the cycle time is shortened, the shrinkage amount of the plug part is specified. Since it does not fall within the range of values, capping defects occur, and the stretched heat-fixed mold that forms a heat-resistant hollow molded body is heavily soiled, and when trying to obtain a transparent hollow molded body, the mold is frequently cleaned. There must be. On the other hand, if it exceeds 50000 ppm, the crystallization speed will be high, and the crystallization of the plug part of the hollow molded body will be excessive, and the amount of shrinkage and shrinkage of the plug part will not fall within the specified value range. Leakage occurs, and the preform for the hollow molded body is whitened, so that normal stretching is impossible. Further, in the case of a sheet-like material, if it exceeds 50000 ppm, the transparency becomes very poor, the stretchability is also impaired, and normal stretching is impossible, and only a stretched film with large thickness spots and poor transparency can be obtained. .

  Examples of the polyolefin resin blended in the polyester composition of the present invention include a polyethylene resin, a polypropylene resin, and an α-olefin resin. These resins may be crystalline or amorphous.

  Examples of the polyethylene resin blended in the polyester composition of the present invention include ethylene homopolymer, ethylene, propylene, butene-1, 3-methylbutene-1, pentene-1, 4-methylpentene-1, Other α-olefins having about 2 to 20 carbon atoms such as hexene-1, octene-1, and decene-1, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene, Examples thereof include copolymers with vinyl compounds such as saturated epoxy compounds. Specifically, for example, ultra-low / low / medium / high-density polyethylene (branched or linear) ethylene homopolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene- 4-methylpentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer Examples thereof include ethylene resins such as coalescence and ethylene-ethyl acrylate copolymer.

  Moreover, as a polypropylene resin mix | blended with the polyester composition of this invention, the homopolymer of propylene, propylene, ethylene, butene-1, 3-methylbutene-1, pentene-1, 4-methylpentene-1 is mentioned, for example. , Other α-olefins having about 2 to 20 carbon atoms such as hexene-1, octene-1, decene-1, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene, etc. Or a copolymer with a diene such as hexadiene, octadiene, decadiene or dicyclopentadiene. Specific examples include propylene-based resins such as propylene homopolymer (atactic, isotactic, syndiotactic polypropylene), propylene-ethylene copolymer, propylene-ethylene-butene-1 copolymer.

The α-olefin resin to be blended in the polyester composition of the present invention includes homopolymers of α-olefins having about 2 to 8 carbon atoms such as 4-methylpentene-1, such α-olefins, and ethylene. , Copolymers with other α-olefins having about 2 to 20 carbon atoms such as propylene, butene-1,3-methylbutene-1, pentene-1, hexene-1, octene-1, and decene-1. It is done. Specifically, for example, butene-1 homopolymers, 4-methylpentene-1 homopolymers, butene-1-ethylene copolymers, butene-1-propylene copolymers, etc. - methylpentene-1 and C ₂ -C ₁₈ copolymer of α- olefins, and the like.

Moreover, as a polyacetal resin mix | blended with the polyester composition of this invention, a polyacetal homopolymer and a copolymer are mentioned, for example. As the polyacetal homopolymer, the density measured by ASTM-D792 is 1.40 to 1.42 g / cm ³ , and the melt flow ratio (MFR) measured at 190 ° C. and load 2160 g is measured by ASTM D-1238. ) Is preferably in the range of 0.5 to 50 g / 10 min.
Moreover, as a polyacetal copolymer, the density measured by the measuring method of ASTM-D792 is 1.38 to 1.43 g / cm ³ , the melt flow ratio measured at 190 ° C. and the load of 2160 g by the measuring method of ASTM D-1238. A polyacetal copolymer having a (MFR) in the range of 0.4 to 50 g / 10 min is preferred. Examples of these copolymer components include ethylene oxide and cyclic ethers.

  When blending the polyolefin resin or the like in the present invention, the polyester A and / or polyester B, or the polyester composition composed of polyester A, polyester B and polyamide, the content of the resin such as the polyolefin resin is the content. In addition to a conventional method such as a method of directly adding and melt-kneading so as to be in a range, or a method of adding and melt-kneading as a master batch, the resin is used in the production stage of the polyester A and / or polyester B, for example, , During melt polycondensation, immediately after melt polycondensation, immediately after precrystallization, at the time of solid phase polymerization, immediately after solid phase polymerization, or the process from the end of the production stage to the molding stage Or added directly as a powder or a polyester A chip and / or polyester. It is also possible to use a method of mixing the chips of Tell B or a mixture of these polyester chips and polyamide chips by a method such as bringing them into contact with the resin member under flow conditions, or a method of melting and kneading after the contact treatment. it can.

  Here, as a method of bringing the polyester chip into contact with the resin member under flow conditions, it is preferable that the polyester chip is brought into collision contact with the member within the space where the resin member is present. For example, immediately after the melt polycondensation of polyester, immediately after precrystallization, immediately after solid-phase polymerization, etc., at the time of filling and discharging the transport container in the transport stage as a product of polyester chips, etc. When the molding machine is inserted in the chip molding stage, a part of pneumatic transportation piping, gravity transportation piping, silo, magnet catcher magnet part, etc. is made of the resin, or the resin film, sheet, molded body, etc. Or lining the resin, or installing the resin member such as a rod-like or net-like body in the transfer path To include a method of transferring the polyester chips. The contact time of the polyester chip with the member is usually an extremely short time of about 0.01 seconds to several minutes, but a small amount of the resin can be mixed into the polyester.

  In the polyester composition of the present invention, other additives such as known ultraviolet absorbers, antioxidants, oxygen absorbers, oxygen scavengers, lubricants added from the outside, and internal precipitation during the reaction are carried out as necessary. Various additives such as lubricants, mold release agents, nucleating agents, stabilizers, antistatic agents, bluing agents, dyes and pigments may be blended. It is also possible to mix ultraviolet ray-blocking resin, heat-resistant resin, recovered products from used polyethylene terephthalate bottles, and the like at an appropriate ratio.

  In addition, when the polyester composition of the present invention is used for a film, the polyester composition contains calcium carbonate, magnesium carbonate, barium carbonate in order to improve handling properties such as slipping property, winding property, and blocking resistance. , Inorganic particles such as calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, organic salt particles such as terephthalate such as calcium oxalate, calcium, barium, zinc, manganese, magnesium, divinylbenzene, styrene, acrylic Inactive particles such as crosslinked polymer particles such as acid, methacrylic acid, acrylic acid or a vinyl monomer of methacrylic acid, or a copolymer thereof can be contained.

(Uses such as polyester moldings)
The polyester composition of the present invention is formed by using a generally used melt molding method to form a sheet-like material, a biaxially stretched film, a hollow molded body, a tray or other packaging material, or by another melt extrusion method. A coated coating can be formed on the substrate. Moreover, the polyester composition of this invention can be used also as 1 component layers, such as a multilayer molded object and a multilayer film.

The sheet-like material comprising the polyester composition of the present invention can be produced by a means known per se. For example, it can be manufactured using a general sheet forming machine equipped with an extruder and a die.
Further, this sheet-like material can be formed into a cup shape or a tray shape by pressure forming or vacuum forming. Moreover, the polyester molding from the polyester composition of this invention can be used also for the use of the tray-shaped container for cooking food with a microwave oven and / or an oven range, or heating frozen food. . In this case, after the sheet-like material is formed into a tray shape, it is thermally crystallized to improve heat resistance.

Another use of the polyester composition of the present invention is a film laminated on one or both sides of a laminated metal plate. Examples of the metal plate used include tinplate, tin-free steel, and aluminum.
As a laminating method, a conventionally known method can be applied, and it is not particularly limited. However, it is preferable to carry out by a thermal laminating method that can achieve organic solvent-free and can avoid adverse effects on the taste and odor of food products due to the residual solvent. In particular, the thermal laminating method by energization processing of a metal plate is particularly recommended. In the case of double-sided lamination, they may be laminated simultaneously or sequentially.
Needless to say, a film can be laminated to a metal plate using an adhesive.
Moreover, a metal container is obtained by shape | molding using the said laminated metal plate. The method for forming the metal container is not particularly limited. Further, the shape of the metal container is not particularly limited, but is preferably applied to a so-called two-piece can produced by a molding process such as drawing, drawing and ironing, and stretch draw molding. The present invention can also be applied to a so-called three-piece can in which a top cover suitable for filling a food product such as a coffee drink is wrapped to fill the contents.

Below, the concrete manufacturing method about the various uses in the case of PET is demonstrated easily.
In producing a stretched film, the stretching temperature is usually 80 to 130 ° C. Stretching may be uniaxial or biaxial, but biaxial stretching is preferred from the viewpoint of film physical properties. In the case of uniaxial stretching, the stretching ratio is usually 1.1 to 10 times, preferably 1.5 to 8 times. In the case of biaxial stretching, the longitudinal and transverse directions are usually 1.1 to 8 times, respectively. Preferably, it may be performed in a range of 1.5 to 5 times. The vertical / horizontal magnification is usually 0.5 to 2, preferably 0.7 to 1.3. The obtained stretched film can be further heat-set to improve heat resistance and mechanical strength. The heat setting is usually performed under tension at 120 to 240 ° C., preferably 150 to 230 ° C., usually for several seconds to several hours, preferably several tens of seconds to several minutes.

  In producing a hollow molded body, a blow molded from the polyester composition of the present invention is stretch blow molded, and an apparatus conventionally used in blow molding of PET can be used. Specifically, for example, once a preform is formed by injection molding or extrusion molding, the plug part and the bottom part are processed as it is, and then reheated, and then biaxial stretch blow molding such as hot parison method or cold parison method The law applies. The molding temperature in this case, specifically, the temperature of each part of the cylinder of the molding machine and the nozzle is usually in the range of 260 to 300 ° C. The stretching temperature is usually 70 to 120 ° C., preferably 90 to 110 ° C., and the stretching ratio is usually 1.5 to 3.5 times in the longitudinal direction and 2 to 5 times in the circumferential direction. The obtained hollow molded body can be used as it is, but in particular in the case of beverages that require hot filling, such as fruit juice beverages and oolong teas, in general, heat-setting treatment is performed in a blow mold, Used to impart sex. The heat setting is usually performed at 100 to 200 ° C., preferably 120 to 180 ° C. for several seconds to several hours, preferably several seconds to several minutes, under tension by compressed air or the like.

  In addition, in order to impart heat resistance to the plug part, the plug part of the preform obtained by injection molding or extrusion molding is crystallized in a far-infrared or near-infrared heater installation oven, or after the bottle is formed, The stopper is crystallized with the heater.

  The polyester composition of the present invention can also be used for the production of a stretched hollow molded body by a so-called compression molding method in which a preform obtained by compression molding a melt mass cut after melt extrusion is stretch-blown. Can do.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
The main characteristic value measurement methods will be described below.
The composition and characteristics of the polyester are measured after the chips are frozen and ground and mixed thoroughly.

(1) Intrinsic viscosity of polyester (IV)
It calculated | required from the solution viscosity at 30 degreeC in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent. The IV of the polyester composition was a weighted average value calculated from the IV of the constituent polyester.

(2) Polyethylene glycol content of polyester (hereinafter referred to as [DEG content])
Decomposition with methanol, the amount of DEG was quantified by gas chromatography, and expressed as a ratio (mol%) to the total glycol components.

(3) Polyester cyclic trimer content (hereinafter referred to as “CT content”)
300 mg of the frozen and ground sample is dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixed solution (volume ratio = 2/3), and further diluted with 30 ml of chloroform. To this is added 15 ml of methanol to precipitate the polymer, followed by filtration. The filtrate was evaporated to dryness, brought to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

(4) Acetaldehyde content of polyester (hereinafter referred to as “AA content”)
Sample / distilled water = 1 g / 2 cc of glass ampoule substituted with nitrogen was sealed and subjected to extraction treatment at 160 ° C for 2 hours. After cooling, acetaldehyde in the extract was measured by high-sensitivity gas chromatography. The concentration was expressed in ppm. Moreover, the acetaldehyde content of a molded object takes a sample from the plate (A part of FIG. 1) 2 mm thick shape | molded by the method of (14).

(5) Increasing amount of cyclic trimer at the time of melting polyester (△ CT amount)
A sample was taken from a 3 mm thick plate molded at 280 ° C. by the method of (14), dried under reduced pressure at 140 ° C. and 0.1 mmHg or less for about 16 hours, and then 3 g of the sample was placed in a glass test tube and a nitrogen atmosphere It is immersed in an oil bath at 290 ° C. for 60 minutes and melted. The amount of increase in cyclic trimer at the time of melting is determined by the following equation.
The cyclic trimer content of the plate was used as the cyclic trimer content before melting.
Increase in cyclic trimer during melting (wt%) =
Cyclic trimer content after melting (wt%)-cyclic trimer content before melting (wt%)

(6) Measurement of Fine Content About 0.5 kg of resin, sieve (A) with a mesh size of 5.6 mm according to JIS-Z8801, and sieve with a mesh size of 1.7 mm (diameter) 20 cm) (B) was placed on a sieve combined in two stages, and sieved at 1800 rpm for 1 minute with a swing type sieve shaker SNF-7 manufactured by Terraoka. This operation was repeated and a total of 20 kg of resin was sieved. However, when the fine content is small, the amount of the sample is appropriately changed.

  The fine sieved under the sieve (B) is washed with a 0.1% aqueous cationic surfactant solution, then washed with ion-exchanged water, and filtered through a G1 glass filter manufactured by Iwaki Glass Co., Ltd. It was. These were dried together with a glass filter in a dryer at 100 ° C. for 2 hours, then cooled and weighed. Again, the same operations of washing and drying with ion-exchanged water were repeated to confirm that the weight became constant, and the weight of the glass filter was subtracted from this weight to obtain the fine weight. The fine content is the fine weight / the total resin weight that has been sieved.

(7) Measurement of fine melting peak temperature (hereinafter referred to as “fine melting point”) Measured using a differential scanning calorimeter (DSC) manufactured by Seiko Denshi Kogyo Co., Ltd., RDC-220. In (6), fines collected from 20 kg of polyester were dried at 25 ° C. under reduced pressure for 3 days, and then DSC measurement was performed using a 4 mg sample for one measurement at a heating rate of 20 ° C./min. The melting peak temperature on the highest temperature side of the peak temperature is determined. The measurement is performed on a maximum of 10 samples, and the average value of the melting peak temperatures on the highest temperature side is obtained. If there is a single melting peak, the temperature is determined.

(8) Crystallization temperature (Tc1) when the molded body is heated and crystallization temperature (Tc2) when the temperature is lowered
Measured with a differential thermal analyzer (DSC), RDC-220, manufactured by Seiko Electronics Industry Co., Ltd. Using 10 mg of a sample from the center of a 2 mm thick plate of the molded plate (14) below. The temperature was raised at a rate of temperature rise of 20 ° C./minute and held at 290 ° C. for 3 minutes, then the temperature was lowered from 290 ° C. to 240 ° C. at 10 ° C./minute, and further from 240 ° C. to 130 ° C. at 7 ° C./minute. The temperature dropped. The peak temperature of the crystallization peak observed at the time of temperature rise is defined as the crystallization temperature (Tc1) at the time of temperature increase, and the peak temperature of the crystallization peak observed at the time of temperature decrease is defined as the crystallization temperature (Tc2).

(9) Density of polyester chip It was measured at 30 ° C. with a density gradient tube of calcium nitrate / water solution.

(10) Bulk density of polyester and polyamide It was measured by a method according to JIS K6721.

(11) Terminal amino group concentration of polyamide (AEG, μmol / g)
After 0.5 g of sample is dissolved in 50 ml of a phenol / ethanol mixed solvent (volume ratio 4/1) at room temperature, 20 ml of a water / ethanol mixed solvent (volume ratio 3/2) is added and stirred. Thereafter, neutralization titration was performed using hydrochloric acid to determine the terminal amino group concentration.

(12) Terminal carboxyl group concentration of polyamide (CEG, μmol / g)
To 0.5 g of the sample, 20 ml of benzyl alcohol was added and dissolved by heating in an oil bath at 170 to 180 ° C., followed by neutralization titration with an aqueous sodium hydroxide solution to determine the terminal carboxyl group concentration.

(13) Haze (Fraction%)
A sample was cut from the molded product (thickness 5 mm) of the following (14) and measured with a Nippon Denshoku Co., Ltd. haze meter, model NDH2000.

(14) Molding of Stepped Molding Plate The polyester dried under reduced pressure at 140 ° C. for about 16 hours using a vacuum dryer is shown in FIGS. 1 and 2 by an injection molding machine M-150C-DM type injection molding machine manufactured by Meiki Seisakusho. 2 mm to 11 mm having a gate part (G) (A part thickness = 2 mm, B part thickness = 3 mm, C part thickness = 4 mm, D part thickness = 5 mm, E part thickness = 10 mm, F A stepped molded plate having a thickness of part thickness = 11 mm) was injection molded.

Polyester previously dried under reduced pressure using a vacuum dryer DP61 manufactured by Yamato Kagaku was used, and a dry inert gas (nitrogen gas) purge was performed in the molding material hopper to prevent moisture absorption during molding. The plasticizing conditions of the M-150C-DM injection molding machine are as follows: feed screw rotation speed = 70%, screw rotation speed = 120 rpm, back pressure 0.5 MPa, cylinder temperature 45 ° C., 250 ° C. from the bottom of the hopper in order, nozzle Including 280 ° C. or 290 ° C. The injection conditions are 20% for injection speed and holding pressure, and the injection pressure and holding pressure are adjusted so that the weight of the molded product is 146 ± 0.2g. In this case, the holding pressure is 0.5MPa lower than the injection pressure. It was adjusted.
The upper limit of the injection time and pressure holding time is set to 10 seconds and 7 seconds, respectively, and the cooling time is set to 50 seconds. The total cycle time including the time for taking out the molded product is about 75 seconds.

Although the temperature of the mold is always controlled by introducing cooling water having a water temperature of 10 ° C., the mold surface temperature at the time of stable molding is around 22 ° C.
The test plate for evaluating the molded product characteristics was arbitrarily selected from the 11th to 18th shots of the stable molded product after the molding material was introduced and the resin was replaced.

The molding temperature refers to the set temperature of the barrel including the nozzle. A 290 ° C. molding temperature molded plate was used for measuring the AA content of the molded plate, and a 280 ° C. molding temperature molded plate was used for haze evaluation of the molded plate.
2 mm thick plate (A part of FIG. 1) is measured for crystallization temperature (Tc1) at the time of temperature rise, crystallization temperature (Tc2) measurement and AA measurement at the time of temperature drop, and 3 mm thick plate (B part of FIG. 1) is melted. The measurement of the cyclic trimer increase amount (ΔCT amount) at the time is used for the haze (degree%) measurement of the 5 mm thick plate (D portion in FIG. 1).

(15) Molding of hollow molded body The polyester is dried with a drier using dehumidified air, and preformed at a resin temperature of 290 ° C. with a M-150C-DM injection molding machine manufactured by each machine manufacturer (wall thickness: about 3.7 mm). Was molded. The surface temperature of the mold when molding is stable is around 22 ° C. The plug portion of this preform was heat-treated for 180 seconds with a homemade infrared heater, and then a mold pin was inserted to heat-crystallize the plug portion. Next, this preform was biaxially stretched and blown with a LB-01E molding machine manufactured by CORPOPLAST, and then heat-set in a mold set at about 150 ° C. for about 5 seconds to form a container having a capacity of 1500 cc. The stretching temperature was controlled at 100 ° C.
For the purpose of improving the barrier properties, a 1000 cc container was molded in substantially the same manner as described above.

(16) Shape and size of plug portion of hollow molded body preform The shape and size of the preform plug portion crystallized in (15) were visually observed and evaluated as follows.
A: Extremely stable dimensional accuracy was obtained.
○: Stable dimensional accuracy was obtained.
×: Insufficient crystallization to cause poor shape, or excessive crystallization to cause poor dimensional accuracy.

(17) Appearance of Hollow Molded Body 100 hollow molded bodies of the above (15) were visually observed and evaluated as follows.
◎: Transparent and no appearance problem △: 1 to 5 hollow moldings with whitened flow pattern or whitened product per 100 hollow molded products ×: Hollow with whitened flow pattern or whitened product per 100 hollow molded products 6 or more compacts

(18) Yellowness of hollow molded body The appearance of the hollow molded body obtained after molding of 100 of (15) was visually observed and evaluated as follows.
◎: No coloring is observed. ○: Although coloring is observed, it is in a practical range. XX: It is considerably colored and has little practicality. XX: The coloring is severe and there is no practicality.

(19) Sensory test Put boiling distilled water into the PET hollow molded body obtained in (15) above, hold for 30 minutes after sealing, cool to 50 ° C., leave at the same temperature for 1 week, flavor and smell after opening Etc. were tested.
Use distilled water as a blank for comparison. The sensory test was carried out by 10 panelists according to the following criteria, and the average values were compared.
(Evaluation criteria)
◎: Feel no strange taste or smell ○: Feel a slight difference from the blank △: Feel a difference from the blank ×: Feel a considerable difference from the blank XX: Feel a very large difference from the blank

(20) Oxygen permeation rate (cc / one container / 24hr / atm)
The permeation amount per 1000 cc bottle was measured at 20 ° C. and 0% RH with an oxygen permeation meter OX-TRAN100 manufactured by Modern Controls.

{Polyethylene terephthalate (PET) used in Examples and Comparative Examples}
(Polyester 1)
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. In addition, crystalline germanium dioxide was dissolved in water by heating, ethylene glycol was added thereto, and the heat-treated catalyst solution, and the ethylene glycol solution of phosphoric acid and ethylene glycol were continuously supplied separately to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The intrinsic viscosity (IV) of the obtained PET resin was 0.54.

After fine removal of this resin, it was subsequently crystallized at about 155 ° C. under a nitrogen atmosphere, further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 208 ° C. under a nitrogen atmosphere. . After solid-phase polymerization, fines were removed by continuous treatment in a sieving step and a fine removal step.
The obtained PET had an intrinsic viscosity of 0.68 deciliter / gram, an acetaldehyde (AA) content of 3.8 ppm, a cyclic trimer content of 0.35 wt%, and a density of 1.398 g / cm ³ . . The properties of the obtained PET are shown in Table-1. The melting point of fine was about 248 ° C.

(Polyester 2A, 3)
Polyesters 2A and 3 were obtained by reacting in the same manner as in Example 1 except that the polycondensation catalyst addition amount and the solid phase polymerization time were changed.
The properties of the obtained PET are shown in Table-1.

(Polyester 2B)
A reaction similar to Pes1 except that the amount of polycondensation catalyst added was reduced and the final polycondensation time was shortened to obtain a melt polycondensation prepolymer with IV = 0.48. The solution was put into a solid phase polymerization apparatus, crystallized at 70 to 160 ° C. under reduced pressure while rotating, and then subjected to solid phase polymerization at 210 ° C. After the solid phase polymerization, fines were not removed in the sieving step.
The properties of the obtained PET are shown in Table-1.

(Polyester 4, 5)
Each prepolymer was obtained by melt polycondensation in the same manner as in Example 1 except that the esterification conditions, polycondensation catalyst addition amount, and chip size were changed.
The obtained prepolymer was put into a rotary reduced pressure solid phase polymerization apparatus without fine removal, crystallized at 70 to 160 ° C. under reduced pressure while rotating, and then subjected to solid phase polymerization at 210 ° C. After the solid phase polymerization, fines were not removed in the sieving step. Polyester 5 was solid phase polymerized with a longer solid phase polymerization time than polyester 4.
The properties of the obtained PET are shown in Table-1.

(Polyester 6, 7)
As the polycondensation catalyst, the reaction was carried out in the same manner as in Example 1 except that an ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and an ethylene glycol solution in which ethylene glycol was heat-treated in advance were used. Thus, polyesters 6 and 7 were obtained. No ethylene glycol phosphate solution was added. The properties of the obtained PET are shown in Table-1.

(Polyester 8, 9)
Polyesters 8 and 9 were obtained by reacting in the same manner as in Example 1 except that an ethylene glycol solution of titanium tetrabutoxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used as the polycondensation catalyst. No ethylene glycol phosphate solution was added. The properties of the obtained PET are shown in Table-1.

(Polyester 10, 11)
Using a mixture of terephthalic acid / isophthalic acid = 98.5 parts by weight / 1.5 parts by weight as a raw material, using an ethylene glycol solution of antimony trioxide and an ethylene glycol solution of cobalt acetate as a polycondensation catalyst, Polyesters 10 and 11 were obtained by reacting in the same manner as in Example 1 except that the temperature was 203 ° C.
The properties of the obtained PET are shown in Table-1.

{Polyamide used in Examples and Comparative Examples}
(Polyamide 1, 2, 3)
Using an aqueous solution having a concentration of about 80% by weight or more of metaxylylenediamine and adipic acid, a continuous production apparatus composed of a raw material preparation step, an amidation reaction step, an initial polycondensation reaction step, and a late polycondensation reaction step, The polycondensation time was appropriately changed within about 120 minutes of production time. Each was processed with a sieving machine after polycondensation.
Sodium hypophosphite was added as a phosphorus atom-containing compound (P residual amount = 190 ppm). The total amount of sodium hypophosphite and sodium hydroxide was about 3 times mol of phosphorus atoms.
Moreover, the characteristics such as AEG and CEG were changed by changing the use ratio of metaxylylenediamine and adipic acid and the polymerization conditions.
These polyamides have a secondary transition point of about 65 ° C.

(Polyamide 4)
The chip size was changed by a batch method in which a 50% by weight aqueous solution of metaxylylenediamine-adipate was heated in a polymerization kettle under pressure and normal pressure for polycondensation. The production time was about 550 minutes. No fine removal treatment was performed after the polycondensation.

(Polyamide 5)
An aqueous solution having a concentration of about 80% by weight or more of a raw material composition prepared by adjusting metaxylylenediamine, adipic acid, and isophthalic acid as raw materials so as to correspond to the compositions shown in Table 2 using the same apparatus used for the production of polyamide 1. , And obtained by polycondensation within about 120 minutes of production time. The secondary transition point is about 105 ° C.

(Polyamide 6)
It is obtained by polycondensation in the same manner using an aqueous solution having a concentration of about 80% by weight or more of a raw material composition prepared by adjusting metaxylylenediamine, adipic acid, and ε-caprolactam as raw materials to correspond to the composition of Table 2. It is a thing. The secondary transition point is about 71 ° C.
Table 2 shows the properties of the polyamide used in the above test.

Example 1
The polyester 1, 80 parts by weight, polyester 3, 20 parts by weight and polyamide 1, 3 parts by weight were blended, and evaluation was performed using a molded plate and a hollow molded container obtained by the methods (14) and (15). The results are shown in Table 3.
The AA content of the molded plate is good at 5.1 ppm and the haze of the molded plate is good at 12.3%, the yellowing degree of the hollow molded body, the shape and dimensions of the preform plug part, the appearance and the sensory function of the hollow molded container The test was fine.
(Examples 2, 3, 4, 5, 8)
Evaluation was similarly performed by the composition shown in Table 2. The results are shown in Table 3.
All the properties evaluated were good.

(Example 6)
For polyester 2A and polyester 3, linear low density polyethylene (MI = about 0.9 g / 10 min, density = about 0.923 g / cm) on part of the transportation pipe made of SUS304 connected to the transportation container filling process ³ ) The product was transported in a transport pipe connected with a cylindrical pipe made of the product, and contact treatment was performed under flow conditions. After the contact treatment, it was further treated in an airflow classification process. The polyethylene contents were about 10 ppb and about 11 ppb, respectively, Tc1 of the molded plate was 160 ° C. and 165 ° C., and Tc2 was 177 ° C. and 174 ° C., respectively.
A mixture of 70 parts by weight of polyester 2A treated with polyethylene in this way and 30 parts by weight of polyester was molded and evaluated in the same manner as in Example 1. The results are shown in Table 3. All the properties evaluated were good.

(Example 7)
Polyester 2A and polyester 3 were treated with ion-exchanged water as follows.
For water treatment of polyester chips, the apparatus shown in FIG. 3 is used. The raw material chip supply port (1) at the upper part of the treatment tank, the overflow discharge port (2) located at the upper limit level of the treatment water in the treatment tank, and the lower part of the treatment tank A discharge port (3) for the mixture of polyester chips and treated water, treated water discharged from this overflow discharge port, treated water discharged from the treatment tank, and draining discharged from the discharge port at the bottom of the treatment tank Pipe (6) in which the treated water passing through the device (4) is sent again to the water treatment tank via the fine powder removing device (5) whose filter medium is a paper-made continuous filter, and these fine water-removed treated water A tower-shaped treatment tank having an internal capacity of about 50 m ³ and equipped with an adsorption tower (8) for adsorbing acetaldehyde in treated water after fine powder removal, and a new ion-exchanged water introduction port (9). used.

After removing the fine and film-like substances from the polyester chip by the airflow classification process and the vibration sieving process, the upper part of the treatment tank is transferred to a water treatment tank controlled at a treatment water temperature of 95 ° C. at a rate of 50 kg / hour. The feed port (1) was continuously charged for water treatment, and the PET port was continuously withdrawn from the discharge port (3) at the bottom of the treatment tank at a rate of 50 kg / hour.
After the water treatment, fines and the like were removed in the vibration sieve process and the airflow classification process.

The fine content of polyester 2A after water treatment is about 70 ppm, Tc1 of the molded plate is 165 ° C., Tc2 is 178 ° C., the fine content of polyester 3 after the treatment is about 100 ppm, Tc1 of the molded plate is 171 ° C., Tc2 Was 174 ° C., and other characteristics were unchanged.
The compositions shown in Table 3 comprising the polyester thus obtained were evaluated in the same manner. The results are shown in Table 3. All the properties evaluated were good.

(Comparative Example 1)
The polyester 4 was evaluated in the same manner according to the composition shown in Table 3.
Obviously, the shape and size of the preform plug portion of Comparative Example 1 and the sensory test were poor as compared with the Examples. The results are shown in Table 3.

(Comparative Example 2)
Similarly, the polyester composition composed of polyester 4 and polyamide 1 was evaluated by the composition shown in Table 3.
Obviously, in Comparative Example 2, the yellowing degree of the hollow molded body was considerably colored as x in Comparative Example 2, and the shape and size of the preform plug portion were poor. The results are shown in Table 3.

(Comparative Example 3)
Evaluation was similarly performed by the composition shown in Table 3.
Obviously, the shape and dimensions of the preform plug portion, the appearance of the hollow molded body, and the sensory test were poor as compared with the examples. The results are shown in Table 3.

(Comparative Example 4)
Similarly, the polyester compositions composed of polyester 2B, polyester 3, and polyamide 4 were evaluated according to the compositions shown in Table 3.
Obviously, the shape and size of the preform plug portion, the degree of yellowing of the hollow molded body, the appearance of the hollow molded body, and the sensory test were poor as compared with the Examples. The results are shown in Table 3.

(Examples 9 to 14)
The polyester compositions shown in Table 4 were evaluated in the same manner. All the properties evaluated were good.
The results are shown in Table 4.

(Comparative Examples 5 to 8)
The polyester compositions shown in Table 4 were evaluated in the same manner. Among the evaluated characteristics, the yellowness of the hollow molded body, the appearance of the hollow molded body, and the shape and dimensions of the preform plug portion were poor.
The results are shown in Table 4.

(Examples 15 to 19)
For the purpose of improving the barrier property, the polyester composition shown in Table 5 was evaluated in the same manner for a 1000 cc stretched hollow molded body. All the properties evaluated were good.
The results are shown in Table 5.

(Comparative Examples 9-12)
The polyester compositions shown in Table 5 were evaluated in the same manner as Example 15. Among the evaluated characteristics, the shape and dimensions of the preform plug portion were all poor. In Comparative Examples 10, 11, and 12, the yellowness of the hollow molded body was also poor.
The results are shown in Table 5.

  In the present invention, the flow characteristics are improved, the amount of aldehyde generated during molding is small, the hue and transparency are excellent, there are no problems in terms of variation in transparency, crystallization speed and crystallization speed, and Provided is a polyester composition that gives a molded article having excellent mechanical properties such as pressure resistance when formed into a molded article. In addition, since the polyester composition of the present invention has improved flow characteristics, there is little distortion during molding, and a molded article having excellent heat-resistant dimensional stability, particularly a hollow molded article, can be efficiently produced by high-speed molding, and It provides a molded article having very good heat resistance. The polyester composition of the present invention can meet high quality requirements in the field of containers, sheets and the like.

Plan view of stepped plate Side view of stepped plate Schematic diagram of water treatment equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material chip supply port 2 Overflow discharge port 3 Drainage port of polyester chip and treated water 4 Drainage device 5 Fine removal device 6 Pipe 7 Recycled water and / or ion exchange water inlet 8 Adsorption tower 9 Ion Exchange water inlet

Claims (10)

A polyester composition comprising, as main components, at least two polyesters having substantially the same composition and different intrinsic viscosities and at least one polyamide, wherein the intrinsic viscosities between at least two of the polyesters A polyester composition characterized in that the difference is in the range of 0.05 to 0.30 deciliter / gram. A polyester composition containing 0.01 to 30 parts by weight of polyamide with respect to 100 parts by weight of polyester containing the following polyester A and polyester B having ethylene terephthalate as a main repeating unit as a main component, and having an intrinsic viscosity of polyester A The difference in intrinsic viscosity IV _B between IV _A and polyester B is in the range of 0.05 to 0.30 deciliter / gram, and the difference between the crystallization temperature of polyester A when it cools and the temperature of polyester B when it cools is 15 ° C. The polyester composition characterized by being within.
Polyester A: Polyester having intrinsic viscosity IV _A of 0.60 to 0.80 deciliter / gram, crystallization temperature measured by DSC at 140 to 178 ° C., and crystallization temperature at 160 to 190 ° C. .
Polyester B: Polyester having intrinsic viscosity IV _B of 0.73 to 0.95 deciliter / gram, crystallization temperature measured by DSC at 140 to 178 ° C., and crystallization temperature at 160 to 190 ° C. . The polyester composition according to claim 1, wherein the polyamide is a partially aromatic polyamide. The polyester composition according to claim 3, wherein the partially aromatic polyamide is a polyamide containing at least 70 mol% of repeating units composed of metaxylylenediamine and adipic acid. The polyester composition according to any one of claims 1 to 4, wherein an acetaldehyde content of the molded article made of the polyester composition is 15 ppm or less. The polyester composition according to any one of claims 1 to 5, wherein the cyclic ester oligomer content is 70% or less of the cyclic ester oligomer content of the melt polycondensation polyester prepolymer. The polyester composition according to any one of claims 1 to 6, wherein an increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C for 60 minutes is 0.40% by weight or less. A polyester molded article obtained by molding the polyester composition according to claim 1. A polyester molded body, wherein the polyester molded body is a hollow molded body, a sheet-like product, or a stretched film obtained by stretching the sheet-like product in at least one direction. A coating obtained by melt-extruding the polyester composition according to any one of claims 1 to 7 on a substrate.

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