JP2007138157A - Polyester composition and method for producing polyester molded article and polyester blow-molded article made thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition having suppressed formation of aldehydes such as acetaldehyde and cyclic ester oligomers in molding or extrusion coating process and giving a molded article and coated material having excellent transparency and little variation of the transparency. <P>SOLUTION: The polyester composition contains at least two kinds of crystalline polyesters as main components. Not less than 85 mol% of the acid component and not less than 85 mol% of the glycol component of each polyester constituting the polyester composition are same acid component and same glycol component, the intrinsic viscosity difference of the polyesters is 0.05-0.30 dL/g, the difference of the copolymer component contents of the polyesters is ≤10.0 mol%, and the haze of a plate of 5 mm thick produced by molding the polyester at 290°C is ≤25%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a polyester suitably used as a raw material for a hollow molded body such as a bottle for beverages, a molded body such as a sheet, a film, or a coating coated on a substrate such as paper or film. The present invention relates to a composition and its use. In particular, a polyester composition that provides a molded product or a coating having excellent transparency and little variation in transparency, and the transparency and flavor retention comprising these, are suppressed in the formation of aldehydes such as acetaldehyde and cyclic ester oligomers during molding. The present invention relates to a polyester molded article having excellent properties. Moreover, this invention relates to the manufacturing method of the polyester molded object which has the said characteristic.

  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 a 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 stretch blow molded to form a soft drink. It is made into a hollow molded container for heat treatment, or the preform plug portion is heat-treated (crystallization of the plug portion) and then stretch blow molded and the body portion is heat-treated (heat set) to be molded into a heat-resistant or pressure-resistant hollow molded container. It is common.

  However, PET contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. In addition, 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 such as 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 the reduction of the acetaldehyde content in the beverage container is becoming increasingly important. 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.

  Also, a method for producing a heat-resistant polyester container in which a preform formed from two types of molten PET compositions having different intrinsic viscosities of 0.03 or more is treated with a heat-setting mold under specific temperature conditions (for example, Patent Document 8). And a heat-resistant polyester container obtained (see, for example, Patent Document 9), having an intrinsic viscosity of 0.60 to 0.70 dl / g, a specific temperature increase crystallization temperature, and a specific temperature decrease crystallization temperature Production of a heat resistant polyester container for stretching and blowing a preform from a mixture of polyester and a polyester having an intrinsic viscosity of 0.77 to 0.90 dl / g, a specific crystallization temperature at elevated temperature and a specified crystallization temperature at lowered temperature Although methods (for example, refer to Patent Document 10) have been proposed, a molded article having stable transparency and a reduced acetaldehyde content can be obtained by these methods. There is still a problem.

  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 11) or thermoplastic polyester A polyester container (for example, see Patent Document 12) made of a polyester composition containing a specific polyamide whose terminal amino group concentration is regulated within a certain range has been proposed. There are still problems in terms of fluctuations.

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. 62-43851 Japanese Examined Patent Publication No. 62-58973 Japanese Patent Laid-Open No. 10-287799 Japanese Examined Patent Publication No. 6-6661 Japanese Examined Patent Publication No. 4-71425

  The present invention solves the problems of the conventional methods described above, suppresses the formation of aldehydes such as acetaldehyde and cyclic ester oligomers during molding and extrusion coating, and has excellent transparency and little variation in transparency. Polyester composition that gives a body and a coating, and further, a polyester composition that can efficiently produce a hollow molded body having excellent pressure resistance and heat and pressure resistance by high-speed molding, a polyester molded body comprising them, and the above characteristics It aims at providing the manufacturing method of the polyester molded object which has NO.

  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 containing at least two kinds of crystalline polyesters as main components, and 85 mol% or more of the acid component of each polyester constituting the polyester composition and the glycol component. 85 mol% or more are the same acid component and the same glycol component, respectively, the difference in intrinsic viscosity of the polyester is in the range of 0.05 to 0.30 deciliter / gram, the content of the copolymer component of the polyester The polyester composition is characterized in that the difference between the two is 10.0 mol% or less, and the haze of a 5 mm-thick molded plate obtained by molding the polyester at 290 ° C. is 25% or less.

  The polyester composition of the present invention can be melt-molded and melt-extruded at a lower temperature because of improved flowability when melted in an extruder, and contains aldehydes such as acetaldehyde and other pyrolysis by-products. The amount can be reduced and the transparency can be improved, and a molded article and a coating excellent in flavor retention can be provided. At the same time, since the orientation during heating and stretching is also improved, it is possible to give a stretched molded product having excellent mechanical properties such as elastic modulus and tensile strength, and particularly as a stretched hollow container excellent in pressure resistance or heat and pressure resistance. Used beneficially.

  In addition, since the molding temperature can be lowered for the same reason, it is possible to suppress the formation of cyclic ester oligomers during melt molding, and in particular, since the clogging of the vent portion of the injection mold is suppressed, a hollow molded body can be formed. The polyester composition can be efficiently produced by high-speed molding, and therefore, a polyester composition having high productivity and excellent long-term continuous formability can be provided.

  The difference in intrinsic viscosity of the polyester constituting the polyester composition of the present invention is preferably 0.06 to 0.27 deciliter / gram, more preferably 0.07 to 0.23 deciliter / gram, and particularly preferably 0.10. ~ 0.20 deciliter / gram.

  When the intrinsic viscosity difference of the polyester according to the present invention is less than 0.05 deciliter / gram, the content of aldehyde such as acetaldehyde in the obtained molded product cannot be reduced, and the flavor retention cannot be improved. When the above intrinsic viscosity difference exceeds 0.30 deciliter / gram, thickness irregularities, whitened flow patterns, and the like are generated in the obtained molded product, resulting in a problem of poor transparency. Here, when the polyester composition of the present invention comprises two or more kinds of polyesters, the difference in intrinsic viscosity is the difference in intrinsic viscosity between the maximum polyester and the minimum polyester with respect to the intrinsic viscosity. Hereinafter, the maximum polyester regarding the intrinsic viscosity is referred to as polyester B, and the minimum polyester is referred to as polyester A.

  Polyesters having different intrinsic viscosities used in the present invention are polyesters produced so that the difference in intrinsic viscosities falls within the scope of the present invention in the melt polycondensation reaction step or the subsequent solid phase polymerization reaction step, or These are polyesters obtained by contact treatment with water under the condition that the intrinsic viscosity does not decrease.

  As other production methods for obtaining polyesters having different intrinsic viscosities, there are a method of hydrolyzing polyester by heat treatment with water at a high temperature, a method of melt treatment with an extruder, and the like. However, since the method by hydrolysis is carried out in a solid state, it is very difficult to control the degree of IV reduction, it is difficult to obtain polyester particles having a narrow IV fluctuation range, and particles after hydrolysis treatment Is likely to generate fine powder due to impact during transportation, etc., so that there is a problem that the fluctuation of the transparency and crystallization speed of the molded body when these are used becomes very large. The fluctuation is a big problem. In addition, the method using the melt treatment has problems such as an influence on flavor retention and coloring due to an increase in aldehydes such as acetaldehyde during the treatment. Therefore, the polyester according to the present invention does not include polyester hydrolyzed by a method such as heat treatment under pressure with water or the like, or polyester melt-treated to reduce IV.

  Further, the haze of a 5 mm-thick molded plate obtained by molding the polyester according to the present invention at 290 ° C. is preferably 20% or less, more preferably 15% or less, and most preferably 10% or less. When the haze of the molded plate exceeds 25%, the transparency of the polyester molded body is deteriorated, which is a problem.

  Further, the difference in the content of the copolymer component of the polyester according to the present invention is preferably 5 mol% or less, more preferably 3.0 mol% or less, and most preferably 1.0 mol% or less. When the difference in content of the copolymerization component of the polyester according to the present invention exceeds 10.0 mol%, the difference in melting characteristics at the time of melting becomes too large, and in particular, the content of aldehydes such as acetaldehyde should be reduced as much as possible. In the present invention for the purpose of low temperature molding, there is a problem that mixing between the constituent polyesters becomes insufficient and transparency of the unstretched molded body is deteriorated, heating when the unstretched molded body is heated and stretch-molded This causes the problem of partial crystallization whitening, or the problem that only a coating having a large thickness spot can be obtained. In order to solve this, the melting temperature must be increased, and as a result, the content of aldehyde such as acetaldehyde in the molded product cannot be reduced. Here, when the polyester composition of the present invention comprises two or more kinds of polyesters, the difference in the content of the copolymerization component is the copolymerization component of the maximum polyester and the minimum polyester with respect to the content of the copolymerization component. Represents the difference in the content of.

  In this case, the aldehyde content of the polyester is preferably 10 ppm or less.

  In this case, the cyclic ester oligomer content is preferably 60% or less of the cyclic ester oligomer content of the melt polycondensed polyester prepolymer.

  In this case, it is preferable that the cyclic ester oligomer increase amount is 0.40% by weight or less when melted at a temperature of 290 ° C. for 60 minutes.

  In this case, the acid component is preferably terephthalic acid or 2,6-naphthalenedicarboxylic acid.

  In this case, the copolymer component can be at least one selected from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diethylene glycol, neopentyl glycol, and 1,4-cyclohexanedimethanol.

  In this case, it is a polyester molded body obtained by melt-molding the polyester composition, and the polyester molded body is formed by stretching a hollow molded body, a sheet-shaped material, or this sheet-shaped material in at least one direction. A polyester molded body characterized by being a stretched film.

  Moreover, in this case, it can be a coating characterized by melting and extruding the polyester composition on a substrate.

  Furthermore, the crystalline polyester is a polyester having ethylene terephthalate as a main repeating unit, and the polyester resin containing the crystalline polyester as a main component has a molten resin temperature of 255 to 305 ° C. in a molding machine. The present invention provides a method for producing a polyester molded body characterized by kneading and molding under conditions where the melt residence time in a molding machine is 5 to 500 seconds.

  The present invention is capable of molding at a low temperature because of improved flow characteristics, has excellent transparency, and has a molded product or coating with little aldehyde generation during molding, or mechanical properties such as pressure resistance. The present invention also provides a polyester composition that gives an excellent hollow molded article, a molded article comprising the same, and a method for producing the same.

Hereinafter, embodiments of the polyester composition of the present invention and its application will be described in detail.
That is, the polyester according to the present invention is a crystalline polyester, and is 85 mol% or more of the acid component of the polyester and 85 mol% or more of the glycol component, preferably 90 mol% or more of the acid component and 90 mol% of the glycol component. As described above, more preferably, the crystalline polyester is such that 93 mol% or more of the acid component and 93 mol% or more of the glycol component are the same acid component and the same glycol component, respectively.

  The main dicarboxylic acid component constituting the polyester according to the present invention includes terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid and other aromatic dicarboxylic acids and the like. Functional derivatives, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, lactic acid, glycolic acid, glutaric acid and functional derivatives thereof Etc.

  Moreover, as main glycol components constituting the polyester according to the present invention, aliphatic glycols such as ethylene glycol, 1,3-trimethylene glycol and 1,4-tetramethylene glycol, alicyclic glycols such as cyclohexanedimethanol, etc. Is mentioned.

  Examples of the dicarboxylic acid used as a copolymerization component when the polyester is a copolymer include terephthalic acid, isophthalic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 4,4′- Aromatic dicarboxylic acids such as diphenyl ether dicarboxylic acid, 4,4′-diphenyl ketone dicarboxylic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid, oxycaproic acid and 3-hydroxybutyric acid and functional derivatives thereof, adipine Aliphatic dicarboxylic acids such as acid, sebacic acid, succinic acid, glutaric acid, dimer acid, glycolic acid and malic acid and their functional derivatives, and alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid Acids and their functional derivatives, caprolactone, Such as the lactones of the lactone, and the like.

  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 the like alicyclic glycols, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-β-hydroxyeth Cyclophenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, aromatic glycols such as 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 85 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 85 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.

Furthermore, 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 85 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.

Another preferred example of the polyester according to the present invention is a polyester in which the main structural unit is composed of ethylene-2,6-naphthalate, and more preferably a polyester containing 85 mol% or more of ethylene-2,6-naphthalate units. Particularly preferred are polyesters containing 90 mol% or more of ethylene-2,6-naphthalate units.
Examples of these polyesters include polyethylene-2,6-naphthalate (PEN), poly (ethylene-2,6-naphthalate-ethylene terephthalate) copolymer, poly (ethylene-2,6-naphthalate-ethylene isophthalate) copolymer Examples thereof include a polymer and a poly (ethylene-2,6-naphthalate-dioxyethylene-2,6-naphthalate) copolymer.

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 85 mol% or more of 1,4-cyclohexanedimethylene terephthalate units. And a polyester containing 90 mol% or more of 1,4-cyclohexanedimethylene terephthalate units.
Examples of these polyesters include poly-1,4-cyclohexanedimethylene terephthalate (PCT), poly (1,4-cyclohexanedimethylene terephthalate-ethylene terephthalate) copolymer, and the like.

  Another preferred example of the polyester according to the present invention is a polyester whose main structural unit is composed of lactic acid units, more preferably 85 mol% or more, particularly preferably 90 mol% or more of lactic acid units. It is.

  Another preferred example of the polyester according to the present invention is a polyester in which the main structural unit is composed of glycolic acid units, more preferably 85 mol% or more, particularly preferably 90 mol% of glycolic acid units. It is the polyester containing above.

  Another preferred example of the polyester according to the present invention is a polyester in which the main structural unit is composed of succinic acid units, more preferably 85 mol% or more of succinic acid units, and particularly preferably 90 mol% of succinic acid units. It is the polyester containing above.

  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, ethylene glycol, and if necessary, other copolymerization components are directly reacted and esterified while distilling off water, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst, Or transesterification by reacting dimethyl terephthalate with ethylene glycol and other copolymerization components if necessary, and transesterifying while distilling off methyl alcohol, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst Manufactured by. 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 1.6 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. As the transesterification catalyst, fatty acid salts such as Zn, Cd, Mg, Mn, Ca, Ba, carbonates and 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, it is preferable to use at least one compound selected from compounds of Ge, Sb, Ti, Sn or Al. 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. The amount of Ge compound used is 10 to 150 ppm, preferably 13 to 100 ppm, and more preferably 15 to 70 ppm as the residual amount of Ge in the polyester.

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 70 to 250 ppm, more preferably 100 to 230 ppm.

  Examples of Ti compounds include tetraethyl titanates, tetraisopropyl titanates, tetra-n-propyl titanates, tetraalkyl titanates such as tetra-n-butyl titanates and partial hydrolysates thereof, titanium acetate, titanyl oxalate, titanyl ammonium oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl succinate, titanyl succinate, titanium trimellitic acid, 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 amount of Ti compound used is 0.1 to 50 ppm, preferably 0.5 to 30 ppm, and more preferably 1 to 20 ppm as the amount of Ti remaining in the polyester.

  Examples of the Sn compound include tin oxide, tin chloride, tin sulfate, tin acetate, tin lactate, and dibutyltin oxide. The amount of Sn compound used is 10 to 100 ppm, preferably 15 to 70 ppm, more preferably 20 to 50 ppm in terms of Sn remaining in the polyester.

  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 100 ppm, more preferably 15 to 50 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.

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.

  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 can be added at any stage of the polyester formation reaction step.

  Further, 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 dimethylester, phenylphosphonic acid diethylester, phenylphosphonic acid Diphenyl ester, ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, methyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 3,5-di isopropyl tert-butyl-4-hydroxybenzylphosphonate, phenyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, octadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 3, 5-di-tert-butyl-4-hydroxybenzylphosphonic acid 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.

After the melt polycondensation polyester is obtained, the melt polycondensation polyester obtained as described above is extruded from the pores into at least one of the following (1) to (4), and more preferably into cooling water satisfying all. It is preferable that chips are formed into a columnar shape, a spherical shape, a square shape, or a plate shape by a method of cutting with a cooling method, or a method of cutting while cooling with cooling water having the same water quality as described above after being extruded in the atmosphere. .
Na ≦ 1.0 (ppm) (1)
Mg ≦ 1.0 (ppm) (2)
Si ≦ 2.0 (ppm) (3)
Ca ≦ 1.0 (ppm) (4)

  The sodium content (Na) in the cooling water is preferably Na ≦ 0.5 ppm, more preferably Na ≦ 0.1 ppm. The magnesium content (Mg) in the cooling water is preferably Mg ≦ 0.5 ppm, more preferably Mg ≦ 0.1 ppm. Further, the content (Si) of silicon in the cooling water is preferably Si ≦ 0.5 ppm, more preferably Si ≦ 0.3 ppm. Furthermore, the calcium content (Ca) in the cooling water is preferably Ca ≦ 0.5 ppm, and more preferably Ca ≦ 0.1 ppm.

  In order to reduce sodium, magnesium, calcium, and silicon in the cooling water, an apparatus for removing sodium, magnesium, calcium, and silicon is installed in at least one place until the industrial water is sent to the chip cooling process. Also, a filter is installed to remove clay minerals such as silicon dioxide and aluminosilicate particles. Examples of the device for removing sodium, magnesium, calcium, and silicon include an ion exchange device, an ultrafiltration device, and a reverse osmosis membrane device.

  When solid-state polymerization is performed on the polyester that has been chipped while cooling with cooling water that does not satisfy the above-described conditions, foreign matters in the molded body of the polyester obtained under such conditions are caused by impurities in the cooling water. There is also a problem that the product value increases and the flavor value deteriorates and the commercial value is lowered.

  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.

Then, in an inert gas atmosphere or under reduced pressure, at a temperature optimum for the prepolymer, the increase in intrinsic viscosity due to solid phase polymerization is 0.10 deciliter / gram or more in a continuous solid phase polymerization apparatus. Solid phase polymerization is performed. 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.

  The continuous solid-state polymerization equipment is a vertical hopper type solid-state polymerization reactor, and the apex angle of the lower inverted conical part where the outlet of the solid-phase polymerized chip is installed is set as the rest of the chip. It is preferable that the angle is appropriately determined from the corner, and a system such as a system in which an accessory facility such as a baffle cone is installed at the tip outlet to prevent the chip from coming off.

  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 average weight (W) 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 (W) of the chips is also preferably 1 to 5 mg / piece. .

  The polyester according to the present invention, particularly the polyester having a haze of 25% or less (the haze of a 5 mm-thick molded plate obtained by molding the polyester at 290 ° C.) is the type and amount of copolymerization component, the type of polycondensation catalyst. In addition, it can be produced by appropriately controlling the amount of addition, melt polycondensation, cooling water quality used for chip formation, solid phase polymerization conditions, fine content, and characteristics thereof. In particular, as the solid phase polymerization apparatus, it is preferable to use the continuous solid phase polymerization apparatus.

  In addition, the content of aldehydes such as acetaldehyde in the polyester composition of 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, the polyester composition of the present invention is a polyester having ethylene terephthalate as a main repeating unit, and when used as a material for containers for low flavor beverages such as mineral water, the polyester composition The acetaldehyde content of the product is desirably 10 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less.

  Further, the polyester composition of the present invention includes polyamide, polyesteramide, low molecular weight amino group-containing compound, hydroxyl group-containing compound, hindered phenyl compound, hindered amine compound, benzotriazole compound, benzophenone as an aldehyde reducing agent. Compound, polyphenol compound, phosphorus stabilizer, sulfur stabilizer, alkali metal salt can be blended, preferably polyamide, benzophenone compound, polyesteramide, phosphorus stabilizer, low molecular weight amino group-containing compound , A hydroxyl group-containing compound, a benzophenone compound, a hindered phenyl compound, and a hindered amine compound can be blended. Most preferably, it is a polyamide, a polyesteramide, or a low molecular weight amino group-containing compound, and the haze of the obtained polyester molded article is good.

Examples of the polyamide blended as the aldehyde reducing agent include at least one polyamide selected from aliphatic polyamide and partially aromatic polyamide.
Specific examples of the aliphatic polyamide include nylon 6, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, nylon 6/66, nylon 6/610, and the like.

As a preferable example of the partially aromatic polyamide, a structural unit derived from metaxylylenediamine or a mixed xylylenediamine containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine and an aliphatic dicarboxylic acid is used. 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.
Further, the partially aromatic polyamide 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.

  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 include at least 20 mol% or more of a structural unit derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid, A polyamide containing 30 mol% or more, particularly preferably 40 mol% or more is preferred.

  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 preferable examples of the partially aromatic polyamide 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 amino such as aminocaproic acid. Derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid obtained by using carboxylic acids, aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid, etc. as copolymerization components The polyamide contains at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more 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.

  Polyester amides include terephthalic acid, polyester amide produced from 1,4-cyclohexanedimethanol and polyethyleneimine, polyester amide produced from isophthalic acid, 1,4-cyclohexanedimethanol and hexamethylenediamine, and terephthalic acid. Polyesteramides made from adipic acid, 1,4-cyclohexanedimethanol and hexamethylenediamine, polyesteramides made from terephthalic acid, 1,4-cyclohexanedimethanol and bis (p-aminocyclohexyl) methane and their A mixture etc. are mentioned. Examples of the acid component that can be used as a copolymerization component include aliphatic dicarboxylic acids such as sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecanoic acid, undecanoic acid, dodecanedioic acid, and dimer acid. 1,4-cyclohexanedicarboxylic acid, alicyclic dicarboxylic acid such as 1,3-cyclohexanedicarboxylic acid, alicyclic dicarboxylic acid such as 1,2-cyclohexanedicarboxylic acid, orthophthalic acid, xylylene dicarboxylic acid, naphthalenedicarboxylic acid Aromatic dicarboxylic acids such as

  The polyamide or polyester amide used preferably has a secondary transition point 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 during the drying step or extrusion with the polyester composition, or cannot be quantitatively extruded. Moreover, when exceeding 120 degreeC, when extending | stretching a polyester unstretched molded object, it will not be stretched | uniformly uniformly but a thickness spot etc. will arise and it is unpreferable.

  The shape of the polyamide or polyesteramide chip blended in the polyester composition of 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 1 to 50 mg / piece.

Examples of the low molecular weight amino group-containing compound include aliphatic amine compounds such as stearylamine, 1,8-diaminonaphthalate, 3,4-diaminobenzoic acid, 2-aminobenzamide, N, N′-1,6- Examples thereof include aromatic amine compounds such as hexanedibis (2-aminobenzamide) and 4,4′-diaminodiphenylmethane, triazine compounds such as melamine and benzoguanamine, and amino acids.
Examples of the hydroxyl group-containing compound include polyvinyl alcohol, ethylene vinyl alcohol polymer, sugar alcohol, and trimethylolpropane.

These polyamide compounds, low molecular weight amino group-containing compounds, hydroxyl group-containing compounds and other aldehyde reducing agents may be used alone or in admixture at an appropriate ratio.
The aldehyde reducing agent is, for example, used in an amount of 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the polyester composition of the present invention. Can do.

  The aldehyde reducing agent can be blended by adding a predetermined amount of aldehyde reducing agent at any reaction stage from the production of a low-polymerization degree oligomer of polyester to the production of polyester polymer. For example, the aldehyde reducing agent may be added to a reactor such as an esterification reactor or a polycondensation reactor in an appropriate form such as a fine granule, powder, or melt, or from the reactor to a reactor in the next step. The aldehyde reducing agent or a mixture of the polyester and the polyester may be introduced in a molten state into a transport pipe for the polyester reactant. Furthermore, if necessary, the obtained chip can be subjected to solid phase polymerization in a high vacuum or in an inert gas atmosphere.

  It can also be obtained by a method of mixing a polyester composition and an aldehyde reducing agent by a conventionally known method or a method of mixing an aldehyde reducing agent with a mixture of two or more kinds of polyesters. For example, polyamide chips and two types of polyester chips with different IVs are dry blended with a tumbler, V-type blender, Henschel mixer, etc., and the dry blended mixture once with a single screw extruder, twin screw extruder, kneader, etc. Examples include those obtained by melting and mixing as described above, and those obtained by subjecting chips from the molten mixture to solid phase polymerization in a high vacuum or inert gas atmosphere as necessary.

  Further, a method in which a solution in which the polyamide or the like is dissolved in a solvent such as hexafluoroisopropanol is adhered to the surface of the polyester chip, and the polyester is collided with the member in a space where the polyamide member is present. Examples include a method of attaching the polyamide to the surface of the polyester chip.

  The content of the cyclic ester oligomer in the polyester composition of the present invention is 60% or less, preferably 50% or less, more preferably 40% of the content of the cyclic ester oligomer contained in the melt polycondensation polyester prepolymer of the polyester. % Or less, 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 typical polyester having ethylene terephthalate as the main structural unit, the content of the cyclic trimer of the melt polycondensed polyester prepolymer is about 1.0% by weight. The content of the cyclic trimer in the composition is 0.60% by weight or less, preferably 0.50% by weight or less, more preferably 0.40% by weight or less, and particularly preferably 0.35% by weight or less. Is preferred. The lower limit of the cyclic trimer content 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 a heat-resistant hollow molded article or the like is molded from the polyester composition of the present invention, heat treatment is performed in a heating mold, but the cyclic trimer content exceeds 0.60% by weight. In the melt molding, the oligomer adhesion to the extruder and degassing mouth of the extruder and molding machine, or to the heated mold surface of the molded body increases rapidly, and the cost for removing these increases and production. The transparency of the obtained molded product is extremely deteriorated.

  In addition, when the polyester composition of the present invention is melted at a temperature of 290 ° C. for 60 minutes, the increase amount of the cyclic ester oligomer is 0.40% by weight or less, preferably 0.30% by weight or less, more preferably 0.8%. It is desirable that it is 10% 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, the cyclic ester oligomer increases at the time of molding resin melting, and the die or degassing port of the extruder or molding machine The transparency of a hollow molded article or the like obtained by abrupt increase in oligomer adhesion and clogging to the surface or the like, or oligomer adhesion to the heated mold surface is extremely deteriorated.

  A polyester in which the amount of increase in cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less is produced by deactivation treatment of the polycondensation catalyst remaining in at least one of the constituent polyesters. can do. Of course, it is needless to say that it is most desirable that the polycondensation catalyst of all the polyesters is deactivated. Here, the increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C. for 60 minutes is the 3 mm thickness of the stepped molded plate obtained from the polyester composition by the molding method described in the “Measurement method” section below. This is the value obtained for the sample from the plate.

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 hot water treatment method include a method of immersing polyester in water and a method of applying water on these chips with a shower. 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.
The water to be used is preferably water that satisfies at least one of the above (1) to (4), and more preferably water that satisfies all of (1) to (4).

  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.
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.

  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. At this time, a phosphorus compound is added to a polyester of a catalyst (for example, Ge, Sb) whose catalytic activity is not greatly decreased by a phosphorus compound, and blended with a polyester of a catalyst (for example, Ti, Al) whose catalytic activity is decreased by a phosphorus compound. Is also preferable. Thereby, it is possible to easily obtain a polyester having a molecular weight increased to a desired molecular weight while containing a phosphorus compound.

  In addition, a transesterification reaction between the polyesters occurs at the time of molding, but by deactivating the polycondensation catalyst, this transesterification reaction can be suppressed, so that the conditions during molding can be made wider.

The dispersion ratio Mz / Mn of the molecular weight distribution of the polyester composition of the present invention is preferably 3.90 or more, more preferably 3.92 or more, and most preferably 3.95 or more. When the dispersion ratio Mz / Mn of the molecular weight distribution is less than 3.90, it is necessary to increase the melting temperature at the time of molding in order to maintain the transparency of the molded body. It cannot be reduced.
Here, the dispersion ratio Mz / Mn of the molecular weight distribution is a value calculated by Mz / Mn from the number average molecular weight (Mn) and the Z average molecular weight (Mz) obtained by the GPC method.

  As a method of setting the dispersion ratio Mz / Mn of the molecular weight distribution of the polyester composition to 3.90 or more, a method of blending two or more polymers having substantially the same composition with different Z average molecular weights, an appropriate amount of the polyfunctional compound is set. Methods such as copolymerization and polymerization conditions (for example, in the case of a continuous polymerization apparatus, increase the residence time or adjust the number of polymerization tanks, etc.) can be raised, and two or more types of polymers having different molecular weight distributions can be obtained. A blending method is preferred. The blend may be a molten mixture or a dry blend.

  The polyester composition of the present invention is a polyester composition in which polyester A and polyester B are blended in a composition ratio of preferably 7/93 to 93/7 parts by weight, more preferably 10/90 to 90/10 parts by weight. It is preferable that

  The polyester composition of the present invention can be obtained by, for example, mixing at least two kinds of polyesters to be used by a conventionally known method. For example, a method of dry blending the above polyester with a tumbler, V-type blender, Henschel mixer or the like, and a method of melt-mixing the dry blended mixture one or more times with a single screw extruder, twin screw extruder, kneader, etc. .

  When the polyester composition of the present invention is to be obtained by dry blending by the method as described above, if the variation of the mixing ratio of these polyesters is large, the variation of the intrinsic viscosity and the crystallization characteristics of the molded body made of the polyester composition. As a result, the content of aldehydes such as acetaldehyde, transparency, thickness and other characteristics of the obtained molded product fluctuate, which is 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. In the case of moving the composition, the blending ratio of the constituent polyester may vary. As the variation factors, there are a difference in the chip shape, chip weight and true density (crystallinity).

  The ratio of the average weight (W) of the polyester constituting the polyester composition of the present invention is 1.00 to 1.30, preferably 1.00 to 1.28, more preferably 1.00 to 1.25, most Preferably it is 1.00-1.20. If the ratio of the average weight exceeds 1.30, aldehydes are generated at the time of molding, which is not preferable because a special nozzle is used to manufacture chips, and it is not preferable. It becomes difficult and low-temperature molding becomes difficult and becomes a problem. In particular, when used for a heat-resistant hollow stretch molded article, if the ratio is out of the range of 1.00 to 1.15, the effect of reducing aldehydes such as acetaldehyde and improving the transparency deteriorates. The blending amount of the polyester is likely to occur, which is not preferable because it causes transparency and thickness unevenness of the stretched hollow molded article of polyester.

  Further, it is preferable that the variation of the average weight (W) of each polyester chip constituting the polyester composition of the present invention (eg, difference between maximum weight and minimum weight (R), deviation value (σ), etc.) is small. The ratio (R / W) of the difference (R) between the maximum weight (W1) and the minimum weight (W2) and the average weight (W) (R / W) of each of the polyesters is within 0.5, preferably 0.3. Is more preferably within 0.2, and most preferably within 0.1. When the ratio (R / W) exceeds 0.5, when manufacturing a molded product from the polyester composition, the variation of the blending ratio in the time series direction becomes large, so that the intrinsic viscosity and crystallization of the molded product are increased. Variations in properties occur, resulting in a molded product having large variations in thickness spots, stretch spots, transparency spots, mechanical characteristics, and the like. Further, the lower limit of the ratio (R / W) is 0.01, and even if the ratio (R / W) is reduced below this, the improvement effect does not change.

  Further, the difference in crystallinity of the polyester chips constituting the polyester composition of the present invention is 15% or less, preferably 10% or less, more preferably 8% or less. When the difference in crystallinity exceeds 15%, the difference in meltability between the polyesters is large and the effect of improving the fluidity is deteriorated. As a result, the transparency of the polyester unstretched molded body and stretched hollow molded body can be improved. The effect of reducing the acetaldehyde content is lost, and the blended amount of the polyester tends to occur, which is not preferable because it causes the transparency of the polyester unstretched molded body and the stretched hollow molded body and fluctuations in the acetaldehyde content. . Here, when the polyester composition of the present invention comprises two or more kinds of polyesters, the difference in crystallinity is the difference in crystallinity between the largest polyester and the smallest polyester with respect to the degree of crystallinity. is there. Here, the crystallinity of the chip is calculated from the density of the chip obtained by the following method.

  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.

  The fine content of each 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.

  Further, the difference between the melting point of the fine constituting the polyester composition of the present invention and the melting point of the chip is 15 ° C. or less, preferably 10 ° C. or less, more preferably 5 ° C. or less. In the case where the difference includes fines exceeding 15 ° C., the crystals are not completely melted under the normally used melt molding conditions and remain as crystal nuclei. For this reason, in the case of a hollow molded body, when the hollow molded body plug portion is heated, the crystallization speed becomes faster, 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. In the case of a sheet-like material, the obtained sheet-like material is poor in transparency and has a high crystallization speed, so that normal stretching is impossible, and only a stretched film having large thickness spots and poor transparency can be obtained. Absent.

  However, when trying to obtain a hollow molding preform or sheet-like material with good transparency and stretchability from a polyester composition containing a fine whose melting point of the fine and the melting point of the chip exceeds 15 ° C., It must be melt molded at a temperature about 25-50 ° C. or higher above the melting point of the polyester chip. However, at such a high temperature, the thermal decomposition of the polyester becomes intense, and a large amount of by-products such as acetaldehyde and formaldehyde are generated, which greatly affects the flavor of the contents of the resulting molded body. It becomes. Further, when the polyester composition of the present invention contains at least one resin selected from the group consisting of the following polyolefin resins, polyamide resins, and polyacetal resins, generally these resins are more suitable than the polyester according to the present invention. Since the thermal stability is often inferior, in high temperature molding as described above, it causes thermal decomposition and generates a large amount of by-products. Will be affected.

  When the polyester composition of the present invention is PET, a fine or film-like material having a melting point exceeding 265 ° C. becomes a problem.

  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 5. mol% of the glycol component constituting the polyester. It is 0 mol%, More preferably, it is 1.0-3.0 mol%. When the amount of dialkylene glycol exceeds 7.0 mol%, the thermal stability is deteriorated, and the decrease in molecular weight becomes large at the time of 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).

  And the amount of diethylene glycol copolymerized in the polyester according to the present invention, particularly the polyester in which the main repeating unit is composed of ethylene terephthalate is 1.0 to 5.0 mol% of the glycol component constituting the polyester, Preferably it is 1.3-4.5 mol%, More preferably, it is 1.5-4.0 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large at the time of molding, and the increase in acetaldehyde content and formaldehyde content becomes large, which is not preferable. On the other hand, when the diethylene glycol content is less than 1.0 mol%, the transparency of the obtained molded article is deteriorated.

  The polyester composition of the present invention can be formed into a film, a sheet, a container, or other molded body by using a commonly used melt molding method, or coated on another substrate by a melt extrusion method. A coated coating can be formed.

  In addition, as described above, the polyester composition of the present invention can be prepared by adding a predetermined amount of an aldehyde reducing agent to an arbitrary reactor or transport pipe in the production process of a melt polycondensation polymer so as to have the desired characteristics. After that, it can be directly introduced into the molding process to form a molded body.

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.
The sheet-like material can be formed into a recup 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.

  Moreover, the polyester composition of this invention can be used also as one component layer which took the form of the film form or the coating-film form in composite molded objects, such as a laminated molded object and a laminated film. In particular, it is used for manufacturing containers and the like in the form of a laminate with PET. Examples of laminated molded products include a two-layer structure composed of two layers of an outer layer made of the polyester composition of the present invention and an inner layer of PET, or composed of two layers of an inner layer made of the polyester composition of the present invention and an outer layer of PET. A molded article having a two-layer structure, a three-layer structure composed of an intermediate layer containing the polyester composition of the present invention and an outer layer and an innermost layer of PET, or an intermediate layer between the outer layer and innermost layer containing the polyester composition of the present invention and PET Examples include a three-layered molded body composed of layers, a five-layered molded body composed of an intermediate layer containing the polyester composition of the present invention, an innermost layer of PET, a central layer, and an innermost layer. In the PET layer, other gas barrier resins, ultraviolet blocking resins, heat resistant resins, recovered products from used polyethylene terephthalate bottles, and the like can be mixed and used at an appropriate ratio.

Other examples of the laminated molded body include a laminated molded body with a resin other than polyester such as polyolefin, and a laminated molded body with a different type of substrate such as paper or a metal plate.
There is no restriction | limiting in particular in the thickness of the said laminated molded object, and the thickness of each layer. The laminated molded body can be used in various shapes such as a sheet-like material, a film-like material, a plate-like material, a hollow body, and a container.
The laminate can be produced by co-extrusion using a number of extruders corresponding to the type of the resin layer and a multi-layered multi-die, or with a number of injection machines corresponding to the type of the resin layer. It can also be done by co-injection using an injection runner and injection mold.

Another application 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, but 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, lamination may be performed 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.

  The method for producing a polyester molded body from the polyester composition of the present invention will be briefly described below, but is not limited thereto. The polyester composition of the present invention is molded using a generally used melt molding method after the moisture content is reduced to about 100 ppm or less, preferably 50 ppm or less by heat drying under reduced pressure or heat drying under an inert gas. The body and the covering can be molded.

  As molding conditions, it is generally important to set the molten resin temperature in the range of 240 to 305 ° C, preferably 245 to 300 ° C, more preferably 250 to 290 ° C. As conditions for producing a preform of the polyester composition for a hollow molded body, the molten resin temperature is 255 to 305 ° C, preferably 258 to 300 ° C, more preferably by heating a barrel or a hot runner of an injection molding machine or the like. It is important to set the value in the range of 260 to 290 ° C. Here, the molten resin temperature refers to a temperature at which the resin injected from the tip of a nozzle of an injection molding machine or the like is immediately measured with, for example, a thermocouple thermometer.

  In addition, the melt residence time in the molding machine can be set by arbitrarily selecting the shape of the extruder screw, L / D, etc. and the amount of extrusion in the case of extrusion molding, and in the case of injection molding, the injection molding machine The cycle time, the metering stroke (screw back amount) and the like are arbitrarily set, and the time is set in the range of 5 to 500 seconds, preferably 10 to 300 seconds, and more preferably 30 to 100 seconds. Here, the melt residence time is a residence time in a state where the resin is melted in the molding machine. Specifically, the melt residence time is a time during which the resin is melted and held in a cylinder in the molding machine and in a hot runner or a die. That is.

In the case of injection molding, if the melt residence time is t, t is given by the following formula (5).
t = W × S / P (5)
Here, W: Weight of molten resin (g) in a cylinder and hot runner of an injection molding machine, etc.
S: Molding cycle time (seconds)
P: Molded product weight (g)

  In the present invention, by controlling the molten resin temperature in the range of 255 to 305 ° C. and setting the melt residence time in the range of 5 to 500 seconds, at least two types of ethylene terephthalate are mainly used as the main repeating unit. From a polyester composition containing as a main component a polyester having a low aldehyde content such as acetaldehyde, excellent flavor retention, transparency, and transparent spots (for example, a whitened flow pattern formed on a molded product) And a molded body such as a preform for a hollow molded body having no problem in the shape of the plug portion after crystallization. In particular, in the case of a wall-thickened molded article such as a bottle, these effects become significant.

  When the temperature of the molten resin is less than 255 ° C., the torque load of an injection molding machine or the like is large and molding becomes difficult, and the obtained preform becomes extremely poor in transparency. Moreover, when the temperature exceeds 305 ° C., the thermal decomposition becomes intense and the content of aldehyde such as acetaldehyde becomes high, which is a problem. When the melt residence time is less than 5 seconds, the transparency of the preform is deteriorated due to insufficient melting, and when it exceeds 500 seconds, the transparency of the preform is very good, but aldehydes such as acetaldehyde. As a result, the molding cycle becomes longer and the productivity of the preform is lowered.

  Here, the polyester molded body refers to a polyester molded body such as a sheet-like material or a cup-like material used as it is and the following polyester preform. The polyester preform is a preform obtained by compression molding a molten mass obtained by melt extrusion molding of polyester, a preform obtained by injection molding, or the like. Further, it is a molded body that is melt-extruded and extruded into a pipe shape (so-called direct blow molded body), and then a cylindrical molded body that is further molded into a container, a cup-shaped molded body that is obtained by injection molding, Also included are molded products that are commercialized as containers by laminating paper and non-woven fabrics.

  Moreover, it is possible to improve mechanical strength by extending | stretching the sheet-like material which consists of a polyester composition of this invention at least to a uniaxial direction. The stretched film composed of the polyester composition of the present invention is a sheet-like material obtained by injection molding or extrusion molding, and can be any one of uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching that are usually used for PET stretching. It is molded using a stretching method. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.

Below, the specific manufacturing method about the extending | stretching molded object in the case of PET is demonstrated easily.
In producing a stretched hollow molded body, a foam 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 305 ° 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, it is generally heat-set in a blow mold and heat resistant. 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 blow molded. Can do.

  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. 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 the polyester composition of the present invention, known ultraviolet absorbers, antioxidants, oxygen scavengers, lubricants added from the outside, lubricants precipitated internally during the reaction, mold release agents, nucleating agents, stability Various additives such as an agent, an antistatic agent, a bluing agent, a dye, and a pigment, and a polyamide resin from metaxylylenediamine and adipic acid may be added to improve oxygen permeability.

  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.

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.

(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) Isophthalic acid content (hereinafter referred to as “IPA content”) and diethylene glycol content (hereinafter referred to as “DEG content”) of polyester
Polyester was dissolved in deuterated trifluoroacetic acid / chloroform under deuterium (volume ratio 1/9), and ¹ H-NMR was measured with an AVANCE-500 type NMR apparatus manufactured by Bruca Biospin. It calculated | required from the integral intensity | strength of the peak of the proton of each copolymerization component.
Further, the difference in the content of the copolymer component is obtained by calculating the difference in the total amount of the DEG content and the IPA content.

(3) 3-Carboxybenzaldehyde content in isophthalic acid (hereinafter referred to as “3-CBA content”)
Samples were dissolved in ethanol and quantified by high performance liquid chromatography.

(4) 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, adjusted to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

(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. in the following (15), dried under reduced pressure at 140 ° C. and 0.1 mmHg or less for about 16 hours, and then 3 g of the polyester sample was placed in a glass test tube. It is immersed in an oil bath at 290 ° C. for 60 minutes under an atmosphere and melted. The increase amount of the cyclic trimer at the time of melting is obtained by the following equation.
In addition, the cyclic trimer content before melting was a weighted average value of the cyclic trimer content of the polyester constituting the polyester composition.
Increase amount of cyclic trimer at the time of melting (wt%) =
Cyclic trimer content after melting (wt%)-cyclic trimer content before melting (wt%)

(6) 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. In the case of a hollow molded body, a sample was taken from the mouth. In the case of molding the dry blend composition, the average value of the AA contents of the individual polyesters was used as the AA content of the polyester composition before molding.

(7) Density (ρ) and crystallinity (CR) of polyester chip
The density (ρ) of the chip at 30 ° C. was measured with a density gradient tube of calcium nitrate / water solution.
The crystallinity was calculated from the following formula.
CR = 100ρ _c (ρ−ρ _a ) / ρ (ρ _c −ρ _a )
Where ρ is the density of the chip
ρ _a : amorphous density (1.335 g / cm ³ )
ρ _c : crystal density (1.455 g / cm ³ )

(8) Ratio of average weight (W) and average weight of polyester chip (W _A / W _B )
After removing fines with ion-exchanged water, the weight of 100 dried polyester chips was measured, and the average value was defined as the average weight (W). When the polyester composition is a mixture of two kinds of polyesters, the ratio of the average weight of the polyester chips between the two kinds (W _A / W _B ) is the average weight of the polyester chips having a larger average weight among the two kinds. and W _a, the average weight of the average weight of small polyester chips as _{W B,} was calculated _W a / W _B. When the two types of polyester chips have the same average weight, W _A / W _B is 1.00. Moreover, when it consists of 2 or more types of polyester, it calculates as mentioned above for 2 types of polyester with many mixing ratios.
In this case, the selection of 100 chips was performed by excluding abnormally sized chips. The specific chip exclusion method is as follows.
In calculating the average weight (W) of the chips, 100 chips were randomly selected, and after calculating the average weight (W), the chips having a weight of less than 0.5 W and the chips having a weight of more than 2 W were excluded and excluded. A number of chips were picked again at random, replenished and 100 averages recalculated. This was done until all 100 chips were within 0.5W-2W.

(9) Sodium content and calcium content of polyester About 5 to 10 g of a sample is put in a platinum crucible and incinerated at about 550 ° C., then dissolved in 6N hydrochloric acid and evaporated to dryness, and the residue is dissolved in 1N hydrochloric acid. This solution was measured by atomic absorption spectrometry.

(10) Silicon content of polyester About 5 to 10 g of a sample is put in a platinum crucible and incinerated at about 550 ° C., then sodium carbonate is added and dissolved by heating, and dissolved in 1N hydrochloric acid. This solution was measured with an inductively coupled plasma optical emission spectrometer manufactured by Shimadzu Corporation.

(11) Measurement of Fine Content About 0.5 kg of resin is sieved with a screen (A) having a mesh size of 5.6 mm according to JIS-Z8801 and a screen having 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.

(12) 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 (11), the finely collected fine polyester was frozen and pulverized and mixed, and then dried under reduced pressure at 25 ° C. for 3 days. From now on, 4 mg of sample was used for one measurement, and the DSC was performed at a heating rate of 20 ° C./min. Measure and obtain the melting peak temperature on the highest temperature side of the melting peak temperature. 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.

(13) Haze (degree of haze) and haze spots 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. Moreover, the haze of the molded board (thickness 5 mm) shape | molded continuously 50 times was measured, and the haze spot was calculated | required by the following.
Haze spots = maximum value of haze / minimum value of haze Further, the haze of the stretched hollow molded body was measured with a haze meter, model NDH2000, manufactured by Nippon Denshoku Co., Ltd., by cutting a sample from the bottle body of (15) below.

(14) Molding of stepped molded plate
The polyester dried under reduced pressure at 140 ° C. for about 16 hours using a vacuum dryer has a gate part (G) as 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 (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 part thickness = 11 mm) The stepped molding plate was injection molded.
In order to prevent moisture absorption during molding, a dry inert gas (nitrogen gas) purge was performed in the molding material hopper. 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 molding temperature refers to the set temperature of the barrel including the nozzle.

The stepped molded plate used for measuring the haze of various polyester molded plates used in Examples and Comparative Examples is a molded plate molded at a 290 ° C. molding temperature.
Moreover, the molded board of 280 degreeC shaping | molding temperature was used for the measurement of the molded board haze (%) and molded board haze spot (%) of the polyester composition in an Example and a comparative example.
The test plate for evaluating the characteristics of the molded product 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.
A plate with a thickness of 3 mm (part B in FIG. 1) is used for measurement of an increase in cyclic trimer (ΔCT amount) at the time of melting, and a plate with a thickness of 5 mm (part D in FIG. 1) is used for a haze measurement (degree%). To do.

(15) Molding of hollow molded body 1) Molding of preform In order to prevent moisture absorption of the chip during molding using a polyester chip dried at 140 ° C. for about 16 hours using a vacuum dryer, A dry inert gas (nitrogen gas) purge was performed.
The plasticizing conditions of the M-150C-DM injection molding machine manufactured by Meiki Seisakusho Co., Ltd. are as follows: feed screw rotation speed = 70%, screw rotation speed = 120 rpm, back pressure 0.5 MPa, weighing position 50 mm, cylinder temperature from directly below the hopper In order, the temperature was set to 45 ° C., 250 ° C., and thereafter the molten resin temperature including the nozzle was 280 ° C. The injection conditions were such that the injection speed and holding pressure were 10%, and the injection pressure and holding pressure were adjusted so that the weight of the molded product was 58.6 ± 0.2 g. Adjusted to 5 MPa lower. The cooling time is set to 20 seconds, and the total cycle time including the molded product take-out time is approximately 42 seconds. The preform has an outer diameter of 29.4 mm, a length of 145.5 mm, and a wall thickness of about 3.7 mm.
The mold is always controlled by introducing cooling water having a water temperature of 18 ° C., but the mold surface temperature at the time of molding stability is around 29 ° C. The preform for property evaluation was arbitrarily selected from stable molded products 20 to 50 shots after the start of molding after introducing the molding material and replacing the resin.

2) Molding of stretched hollow molded body (bottle) The preform was biaxially stretched and blown by a LB-01E molding machine manufactured by CORPOPLAST to mold a container (body thickness 0.45 mm) having a capacity of 1500 cc. The stretching temperature was controlled at 100 ° C. and arbitrarily selected from the stable molded products on the 10th to 30th shots from the start of molding. A sample was taken from the mouth of the bottle and used for measurement of acetaldehyde content (AA content) and cyclic trimer content (CT content).

(16) Strength measurement of bottle body part The body part of the bottle formed by the above method is cut into large pieces with a cutter and punched with a super dumbbell cutter model SDMK-1000D manufactured by Dumbbell Co., Ltd. (according to JISK-7162-5A). The strength was measured using a tensile tester SS-207D-U (manufactured by Toyo Baldwin Co., Ltd.).

(17) Appearance of Hollow Molded Body Twenty hollow molded bodies from the tenth molding start of (15) were visually observed and evaluated as follows.
◎: Transparent and no appearance problem △: There is a little whitened flow pattern or whitened product in the hollow molded body ×: White flowed pattern or whitened product in the hollow molded body

(18) Sodium content, Magnesium content, Calcium content and Silicon content of chip cooling water or treated water Chip cooling water is collected and filtered through a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., and the filtrate is manufactured by Shimadzu Corporation. Measurements were made with an inductively coupled plasma emission spectrometer.

(Polyester 1)
In the first esterification reactor containing the reactants in advance, high-purity terephthalic acid (corresponding to 98.0 mol% of the total acid component), isophthalic acid (2.0 mol% of the total acid component) and ethyl glycol Was continuously fed, and the reaction was carried out with stirring at about 250 ° C. and 0.5 kg / cm ² G for an average residence time of 3 hours. Further, crystalline germanium dioxide was dissolved in water by heating, and a catalyst solution in which ethylene glycol was added and heat-treated thereto and an ethylene glycol solution of phosphoric acid were separately supplied continuously 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 for 1 hour at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The obtained PET had an intrinsic viscosity (IV) of 0.53 and a DEG content of 2.7 mol%. The cooling water at the time of chip formation is ion-exchanged water having a sodium content of 0.1 ppm, a calcium content of about 0.05 ppm, a magnesium content of about 0.07 ppm, and a silicon content of about 0.6 ppm. Using.

The resin 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 205 ° C. under a nitrogen atmosphere. After the 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 0.70 deciliter / gram, an acetaldehyde (AA) content of 3.8 ppm, a cyclic trimer content of 0.37% by weight, a chip crystallinity of 52.2%, and a chip. The average weight (W) was 24.5 mg, the sodium content was 0.01 ppm, the calcium content was 0.03 ppm, the silicon content was 0.06 ppm, the fine content was about 50 ppm, and the fine melting point was 251 ° C. The properties of the obtained PET are shown in Table-1. The isophthalic acid used had a 3-carboxybenzaldehyde content of 3 ppm.

(Polyester 2, 5)
Polyester 2 and polyester 5 were obtained by reacting in the same manner as polyester 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. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 3)
Without using isophthalic acid, the amount of polycondensation catalyst added was changed, and as the cooling water for chip formation, the sodium content was about 9.3 ppm, the calcium content was about 10.3 ppm, the magnesium content was about 5.4 ppm, silicon A prepolymer was obtained by melt polycondensation in the same manner as polyester 1 except that water having a content of 11.3 ppm was used. The obtained prepolymer was put into a rotary reduced pressure solid phase polymerization apparatus, crystallized at 70 to 160 ° C. under reduced pressure while rotating, and then solid phase polymerized at 210 ° C. to obtain polyester 3. After the solid-phase polymerization, fines were not removed in the sieving step. The properties of the obtained PET are shown in Table 1. Each sodium content was about 4.2 ppm, calcium content was about 5.3 ppm, and silicon content was about 6.1 ppm.

(Polyester 4)
A prepolymer was obtained by melt polycondensation in the same manner as for polyester 1 except that the copolymerization amount of isophthalic acid and the addition amount of the polycondensation catalyst were changed. The obtained prepolymer was finely removed and then charged into a rotary vacuum solid phase polymerization apparatus. While rotating, the polymer was crystallized at 70 to 160 ° C. under reduced pressure and then solid-phase polymerized at 210 ° C. to obtain polyester 4. After solid-phase polymerization, fines were removed in the sieving step. The properties of the obtained PET are shown in Table 1. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 6, 7)
Polyester 6, by reacting in the same manner as Polyester 1 or Polyester 2, except that an ethylene glycol solution of basic aluminum acetate is used as the polycondensation catalyst and an ethylene glycol solution of Irganox 1222 (manufactured by Ciba Specialty Chemicals) is used as the P compound. 7 was obtained. No ethylene glycol phosphate solution was added. The properties of the obtained PET are shown in Table 2. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 8, 9)
Polyesters 8 and 9 were obtained by reacting in the same manner as Polyester 1 or Polyester 2 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 2. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 10, 11)
Using ethylene glycol solution of antimony trioxide as the polycondensation catalyst, sodium content is about 9.3ppm, calcium content is about 10.3ppm, magnesium content is about 5.4ppm, silicon content as cooling water when chipping A prepolymer was obtained by reacting in the same manner as polyester 1 except that water having an amount of 11.3 ppm was used, followed by melt polycondensation. The obtained prepolymer was put into a rotary reduced pressure solid phase polymerization apparatus, crystallized at 70 to 160 ° C. under reduced pressure while rotating, then subjected to solid phase polymerization at 210 ° C. while changing the solid phase polymerization time, polyester 10, 11 was obtained. After the solid-phase polymerization, fines were not removed in the sieving step. The properties of the obtained PET are shown in Table 2. Each of the sodium content, calcium content, and silicon content was about the same as polyester 3.

(Polyamide 1)
Toyobo nylon MXD6 resin (T600) manufactured by Toyobo Co., Ltd. was used.

Example 1
Polyester composition obtained by blending the above polyester 1 and polyester 2 pellets in a ratio of 7: 3 was molded at 280 ° C. by the method (14), and the molten resin temperature was 280 by the method (15). Evaluation was performed using a preform and a hollow molded container obtained by injection molding at a temperature of 110 ° C. under a condition of a melt residence time of 110 seconds. The results are shown in Table 3. The haze and haze spots of the molded plate are 8.6% and 0.3%, respectively, which are no problem, the stretched hollow molded article has a low AA content of 5.7 ppm, and the appearance and haze of the hollow molded container are also low. There was no problem.

(Example 2)
Evaluation was carried out in the same manner as in Example 1 for the polyester composition of Example 5 in which the above polyester 1,70 parts by weight, polyester 2,30 parts by weight and polyamide 1, 1 part by weight were blended. The results are shown in Table 3. The characteristics of the molded plate were good, and the stretched hollow molded article had a low AA content of 4.9 ppm, a good haze of 1.1%, and other characteristics were satisfactory.

(Example 3)
For the water treatment of the chips of polyester 1 and 2, using the apparatus shown in FIG. 3, the raw material chip supply port (1) at the top of the treatment tank, the overflow discharge port (2) located at the upper limit level of the treatment water in the treatment tank, the treatment Discharge port (3) for the mixture of polyester chip and treated water at the bottom of the tank, treated water discharged from this overflow outlet, treated water discharged from the treated tank, and draining drained from the discharged outlet at the bottom of the treated 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, these fine powder removed treatments A tower-type treatment tank having an internal capacity of about 50 m ^{3 and comprising} an inlet (7) for water, an adsorption tower (8) for adsorbing acetaldehyde in treated water after fine powder removal, and a new ion-exchange water inlet (9) It was used.

  Fine and film-like substances are removed from the polyester 1 or polyester 2 chips by the airflow classification process and the vibration sieving process, and then processed at a rate of 50 kg / hour into a water treatment tank controlled at a treatment water temperature of 95 ° C. Water was treated by continuously supplying from the supply port (1) at the upper part of the tank, and continuously with the treated water at a rate of 50 kg / hour as PET chips from the outlet (3) at the lower part of the processing tank. In the introduced water collected before the ion exchange water inlet (9) of the treatment apparatus, the particle content of 1 to 25 μm in particle diameter is about 1000 particles / 10 ml, the sodium content is 0.05 ppm, and the magnesium content is 0.1. 10 ppm, calcium content is 0.08 ppm, silicon content is 0.18 ppm, and the number of particles having a particle size of 1 to 40 μm of recycled water after treatment in the filtration device (5) and the adsorption tower (8) is about 10,000. Pieces / 10 ml.

After the water treatment, fines and the like were removed in the vibration sieve process and the airflow classification process.
The properties of the obtained polyester were almost the same as before the treatment.
According to the composition shown in Table 3, the polyester composition of Example 3 was evaluated in the same manner as in Example 1. The results are shown in Table 3. The increase amount (ΔCT) of the cyclic trimer at the time of melting is as low as 0.13% by weight, the haze of the molded plate is 8.7%, the haze spot of the molded plate is as good as 0.5%, and the stretched hollow The AA content of the molded product was as good as 5.3 ppm and haze was 0.9%, and the appearance and the shape of the plug were satisfactory, and the contents were not leaked. Further, continuous injection molding of 5000 or more preforms was carried out by the method of (15) 1), but there was no problem with clogging of the exhaust holes of the mold and the transparency of the bottle was good.

(Comparative Example 1)
As shown in Table 3, the polyester composition of Comparative Example 1 was evaluated in the same manner as in Example 1.
Obviously, the haze value and haze spots of the molded plate were large as compared with the examples, and the AA content, appearance and haze of the stretched molded product were not good. The results are shown in Table 3.

(Comparative Example 2)
As shown in Table 3, the polyester 5 of Comparative Example 2 was evaluated in the same manner.
Obviously, the haze value and haze spots of the molded plate were large compared to the examples, and the AA content, appearance, and haze of the stretched molded product were not good. The results are shown in Table 3.

Example 4
According to the composition shown in Table 3, the polyester composition of Example 4 was evaluated in the same manner as in Example 1. The results are shown in Table 4. The haze of the molded plate is 9.0%, the haze spots of the molded plate are as good as 0.6%, the AA content of the stretched hollow molded body is 6.0 ppm, and the haze is as good as 1.1%. There wasn't.

(Example 5)
According to the composition shown in Table 3, the polyester composition of Example 5 was evaluated in the same manner as in Example 1. The results are shown in Table 3. It was as good as Example 1.

(Comparative Example 3)
As shown in Table 3, the polyester composition of Comparative Example 3 was evaluated in the same manner. The results are shown in Table 3.
Obviously, the haze value and haze spots of the molded plate were large as compared with the examples, and the AA content, appearance, and haze of the stretched molded product were not good.

(Example 6)
As a phosphoric acid aqueous solution, phosphoric acid is uniformly attached to the chip surface of a 7: 3 mixture of polyester 6 and polyester 7 so that the molar ratio of P residual content to Al residual content (P / Al) is about 1.7. Evaluation was similarly performed about the made polyester composition.
The results are shown in Table 4. All the evaluated characteristics were as good as in Example 3.

(Example 7)
As a phosphoric acid aqueous solution, phosphoric acid is uniformly attached to the chip surface of a 7: 3 mixture of polyester 8 and polyester 9 so that the molar ratio (P / Ti) of P residual content to Ti residual content is about 1.9. Evaluation was similarly performed about the made polyester composition.
The results are shown in Table 4. All the evaluated characteristics were as good as in Example 3.

Since the present invention has improved flow characteristics, it can be molded at a low temperature, has excellent transparency, and has a pressure resistance when formed into a molded product covering or a molded product with little aldehyde generation during molding. The polyester composition which gives the hollow molded object etc. which were excellent also in mechanical characteristics etc., the molded object consisting thereof, and its manufacturing method can be provided.

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 Drain port of polyester chip and treated water 4 Drainage device 5 Fine removal device 6 Pipe 7 Recycled water and / or ion exchange water introduction port 8 Adsorption tower 9 Ion exchange water introduction port

Claims (11)

A polyester composition containing at least two kinds of crystalline polyester as a main component, wherein 85 mol% or more of the acid component and 85 mol% or more of the glycol component of each polyester constituting the polyester composition are the same. The difference in intrinsic viscosity of the polyester is in the range of 0.05 to 0.30 deciliter / gram, and the difference in content of the copolymerization component of the polyester is 10.0 mol% or less. And the haze of the molding plate of 5 mm thickness which shape | molded the said polyester at 290 degreeC is 25% or less, The polyester composition characterized by the above-mentioned. The polyester composition according to claim 1, wherein the polyester has an aldehyde content of 10 ppm or less. The polyester composition according to claim 1, wherein the cyclic ester oligomer content is 60% 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 3, 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. The polyester composition according to claim 1, wherein the acid component is terephthalic acid or 2,6-naphthalenedicarboxylic acid. The copolymerization component is at least one selected from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diethylene glycol, neopentyl glycol, and 1,4-cyclohexanedimethanol. The polyester composition in any one. The polyester composition according to claim 1, comprising at least one aldehyde reducing agent. A polyester molded article obtained by melt-molding the polyester composition according to claim 1. The polyester molded body according to claim 8, wherein the polyester molded body is any one of a sheet-like material, a film, and a hollow molded body. The polyester molded article according to claim 8, wherein the polyester molded article is a coating obtained by melt-extruding the polyester composition on a substrate. The crystalline polyester according to any one of claims 1 to 4 is a polyester having ethylene terephthalate as a main repeating unit, and a polyester composition containing the crystalline polyester as a main component is a molten resin in a molding machine. A method for producing a polyester hollow molded body, characterized by kneading and molding under conditions of a temperature of 255 to 305 ° C. and a melt residence time in a molding machine of 5 to 500 seconds.

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