JP2000351840A - Polyester composition and polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester composition having a good hue and a low foreign matter content and being excellent in moldability, gas barrier properties, and weather resistance by polymerizing an oligomer obtained by reacting a dicarboxylic acid component based on naphthalenedicarboxylic acid with a glycol component based on 1,3-propanediol in the presence of a specified amount of a germanium compound. SOLUTION: An oligomer obtained by esterifying a dicarboxylic acid component based on naphthalenedicarboxylic acid with a diol component based on 1,3-propanediol in the presence of 30-400 ppm (in terms of the germanium atoms) germanium compound is polymerized in a vacuum to obtain a polyester composition having an intrinsic viscosity of 0.4-1.5 dt/g and having a value L and a value b satisfying the relationships:65<=L-b; and b<=8. This composition is molten with an extruder, extruded onto a rotary cooling drum to form a sheet thereon, stretching the cooled unstretched film in the machine direction by heating, stretching it in the transverse direction by heating, and heat-setting and/or heat-relaxing it to obtain a polyester film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composition and a polyester film, and more particularly to a polyester composition and a polyester film having a good hue and a small amount of foreign matters, and having excellent moldability, weather resistance and gas barrier properties.

[0002]

2. Description of the Related Art Polyesters represented by polyethylene terephthalate have excellent mechanical properties, heat resistance, weather resistance, electrical insulation resistance, and chemical resistance, and are widely used for films, fibers, bottles and other applications. The properties required for such polyesters vary depending on the application, but in the case of films for packaging materials and the like, the weather resistance and gas barrier properties of polyethylene terephthalate are insufficient, and there is a demand for polyesters having better properties.

[0003] In the production of polyester, various metal compounds are usually used as a polycondensation catalyst in order to make the polymerization reaction proceed smoothly. Among them, Sb compounds such as antimony trioxide are widely used as polycondensation catalysts because of their low cost and high polymerization activity. However, when an Sb compound is used as a catalyst, the Sb compound may be reduced to black metal Sb, which causes a problem of darkening the color of the polymer. In addition, the Sb compound may be deteriorated and formed as a foreign substance, which may cause deterioration of process condition and quality of a molded product. Conventionally, various proposals have been made regarding the reduction of foreign matter when an Sb compound is used as a polyester polycondensation catalyst. For example, JP-A-1-275628, JP-A-2-3420
Japanese Patent Application Laid-Open No. H11-163873 proposes a method in which an Sb compound is added at the beginning of a transesterification reaction and used as both a transesterification catalyst and a polycondensation catalyst. Is described as being reduced. However, in this polymerization method, the number of foreign substances due to the Sb compound in the obtained polymer and the color of the polymer do not satisfy the recent required characteristics.

Japanese Patent Application Laid-Open No. Sho 61-231,025 proposes a technique in which an Sb compound is used as a polycondensation catalyst and a small amount of terephthalic acid is added in the latter half of the polymerization to reduce foreign substances deposited on a spinneret during spinning. ing. However, even if this technique is used, foreign matter in the polymer is not sufficiently reduced, and it is difficult to obtain good polymer quality. Further, Japanese Patent Application Laid-Open No. 54-393
No. 90 and Japanese Patent Application Laid-Open No. 60-67529 propose that a mixture obtained by heating and mixing an Sb compound and a phosphorus compound under appropriate conditions in advance is used as a polycondensation catalyst. The effect of reducing foreign matter in the polymer cannot be expected, as is the reduction of foreign matter.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester composition and a polyester film which solve the above-mentioned problems, have a good hue, contain few foreign substances, and have excellent moldability, weather resistance and gas barrier properties. To provide.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
According to the present invention, it is achieved by a polyester composition containing naphthalenedicarboxylic acid as a main dicarboxylic acid component, 1,3-propanediol as a main glycol component, and a germanium compound containing 30 to 400 ppm in terms of germanium atoms. Another object of the present invention is to provide a polyester composition containing naphthalenedicarboxylic acid as a main dicarboxylic acid component, 1,3-propanediol as a main glycol component, and a germanium compound containing 30 to 400 ppm in terms of germanium atoms. This is achieved by a polyester film obtained by melt-extruding a sheet and then forming the film biaxially.

Hereinafter, the present invention will be described. The polyester used in the present invention is a polyester containing naphthalenedicarboxylic acid as a main dicarboxylic acid component and 1,3-propanediol as a main glycol component. Examples of the naphthalenedicarboxylic acid component include 2,6-naphthalenedicarboxylic acid, Examples thereof include 2,7-naphthalenedicarboxylic acid and 1,4-naphthalenedicarboxylic acid. Of these, 2,6-naphthalenedicarboxylic acid is particularly preferred.

The polyester in the present invention may be a polyester homopolymer having naphthalenedicarboxylic acid as a dicarboxylic acid component and 1,3-propanediol as a glycol component, or may have another dicarboxylic acid component as a copolymer component. Or a polyester copolymer obtained by copolymerizing a glycol component at a ratio of 20 mol% or less, preferably 15 mol% or less.

Among them, as the naphthalenedicarboxylic acid component, a polyester homopolymer or copolymer using 2,6-naphthalenedicarboxylic acid is particularly preferable because of its good gas barrier properties and mechanical properties.

As the above-mentioned copolymer component, dicarboxylic acid components other than naphthalenedicarboxylic acid include, for example, terephthalic acid, isophthalic acid, phthalic acid, 4,4'-diphenylcarboxylic acid, 1,2-bis (2-chlorophenoxy acid) ) Ethane-4,4′-dicarboxylic acid, phenylenedioxydiacetic acid, bis (4-carboxymethoxyphenyl)
Aromatic dicarboxylic acids such as sulfonic acid, succinic acid, adipic acid, aliphatic dicarboxylic acids such as sebacic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, hydroxyacetic acid, and oxycarboxylic acids such as 3-hydroxypropionic acid; Can be used.

Further, the naphthalenedicarboxylic acid component is
In the case of 2,6-naphthalenedicarboxylic acid, other naphthalenedicarboxylic acid components such as 2,7-naphthalenedicarboxylic acid and 1,4-naphthalenedicarboxylic acid can be used as the copolymerization component.

In the polyester of the present invention, 1,3-
As a glycol component other than propanediol, a range of 20 mol% or less, preferably 15 mol% or less, for example, ethylene glycol, 1,2-propanediol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, octane Aliphatic glycols such as methylene glycol, 1,4
Alicyclic glycols such as cyclohexane dimethanol,
Aromatic glycols such as 1,3-bis (β-hydroxyethoxy) benzene, bis (β-hydroxyethoxy) bisphenol S, bisphenol A and hydroquinone, and high molecular glycols such as polyethylene glycol and polypropylene glycol are used as copolymer components. can do. As the copolymerization component, ethylene glycol is preferable.

[0013] The polyester in the present invention is usually prepared by subjecting a dicarboxylic acid and a glycol to an esterification reaction,
Glycol ester of dicarboxylic acid and / or a low polymer thereof is produced by a method of transesterifying dicarboxylic acid dialkyl ester and glycol, or a method of reacting dicarboxylic acid and alkylene oxide, and then reducing the product under reduced pressure. It is obtained by heating and polymerizing to a predetermined polymerization degree.

In the polymerization of the polyester, the above-mentioned dicarboxylic acids or their ester-forming derivatives such as lower alcohol esters can be used.

In the present invention, it is necessary to use a germanium compound as the polymerization catalyst used in the polymerization of the polyester from the viewpoints of high polymerization catalyst ability and foreign matters in the obtained polyester. As the germanium compound, it is preferable to use germanium dioxide, and among them, it is preferable to use a so-called amorphous germanium having no crystalline form since particles precipitated in the polymer can be reduced.

The amount of the germanium compound added must be such that the amount of the germanium compound contained in the produced polyester is 30 to 400 ppm in terms of germanium atoms. It is particularly preferable to add the germanium compound so that the amount thereof becomes 40 to 350 ppm in terms of germanium atoms. If the amount of germanium contained in the polyester is less than 30 ppm, sufficient polymerization activity cannot be obtained, and it becomes difficult to produce the polyester. On the other hand, when the amount of germanium contained in the polyester exceeds 400 ppm, not only the hue of the obtained polyester is lowered but also the heat resistance of the polyester is lowered, which is not preferable.

Further, the polyester composition of the present invention comprises
It is preferable that the L value and the b value measured by the ab method satisfy the following formulas (1) and (2).

[0018]

## EQU2 ## 65 ≦ L−b (1) b ≦ 8 (2)

The value of Lb in the above formula (1) is more preferably at least 67, particularly preferably at least 70. Further, the value of b in the above formula (2) is more preferably 7 or less, and particularly preferably 6 or less. The larger the value of L, the better the whiteness, and the larger the value of b, the more yellowish the color becomes. Unless the polyester composition satisfies the conditions of the above formulas (1) and (2), the film is further colored yellow due to the heat history at the time of melt extrusion molding, so that, for example, the hue is poor when used for a packaging film or the like. However, it is not preferable because the consumer's willingness to purchase may be reduced.

The hue of the polyester composition is determined by the above formula (1)
In order to make the range of the formula (2), a germanium compound is used as a polymerization catalyst when the polyester is produced, and the amount of the germanium compound is adjusted so that the amount of the germanium compound contained in the polyester is 30 to 400 ppm in terms of germanium atoms. In addition to this, it can be achieved, for example, by appropriately adjusting the polymerization temperature and polymerization time during polyester polymerization, and not using an antimony compound as a polymerization catalyst.

In producing the polyester composition of the present invention, other additives such as a tinting agent, an antioxidant, an ultraviolet absorber, an antistatic agent and a flame retardant can be used as necessary. . After completion of the melt polycondensation, the mixture is melt-extruded, cooled in a suitable cooling medium such as water, cut into a suitable size, and formed into chips. The shape of the chip may be rectangular, cylindrical (cylindrical), cubic (dice-shaped), or spherical. Further, if necessary, solid-state polymerization can be performed to obtain a predetermined intrinsic viscosity.

The intrinsic viscosity of the polyester in the present invention is not particularly limited, but is preferably in the range of 0.4 to 1.5 (dl / g) from the viewpoint of moldability and the strength of the processed product.

The polyester film of the present invention comprises naphthalenedicarboxylic acid as a main dicarboxylic acid component,
3-propanediol is used as a main glycol component, and a germanium compound is converted to a germanium atom in an amount of 30 to
It is a polyester film obtained by melt-extruding a polyester composition containing 400 ppm into a sheet and then biaxially stretching the film.

For example, the polyester composition of the present invention is melted by an extruder, extruded into a sheet on a rotary cooling drum, and the unstretched film obtained by cooling is heated in the longitudinal direction.
Stretched to a uniaxially stretched film, then heated in the transverse direction,
It can be obtained by stretching, heat setting and / or heat relaxation.

The thickness of the polyester film of the present invention is
It is preferably from 1 to 300 μm, particularly preferably from 1 to 150 μm. When the thickness of the film is less than 1 μm, the thickness is too small to stabilize the film forming process, and in extreme cases, the film may be cut. On the other hand, if the film thickness exceeds 300 μm, the quality becomes excessive and uneconomical. Although the stretching ratio varies depending on the application, it is preferable that both the longitudinal stretching and the transverse stretching ratio be in the range of 2 to 6 times. When the stretching ratio is 2 times or less, the orientation of the film is insufficient and the mechanical strength is insufficient. On the other hand, if the stretching ratio exceeds 6 times, the stretching ratio is too high, so that film formation may be difficult, and the quality may be excessive.

The polyester film of the present invention can be provided with lubricity as required. The means for imparting lubricity is not particularly limited, and for example, a method of dispersing a lubricant such as SiO ₂ , BaSO ₄ , CaCO ₃ , alumina, alumina silicate, crosslinked organic particles in a polymer, a method of easily dispersing a lubricant on the surface of a film, A method of providing a layer having lubrication can be used.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples. In addition, each characteristic value in an example was measured by the following method. In the examples, “parts” means “parts by weight”.

1. Intrinsic viscosity Measured at 35 ° C. in a phenol / tetrachloroethane (6: 4 weight ratio) mixed solvent.

2. Metal content X-ray fluorescence (Rigaku Electric Industry Co., Ltd. X-ray fluorescence type 3270)
The amount of metal in the polymer (unit pp)
m) was measured. 3. Foreign substance size 1 g of the chip is thoroughly washed with acetone and then with chloroform, and then dissolved in a solution of hexafluoroisopropanol (hereinafter referred to as HFIP) / chloroform = 1/1, and filtered through a membrane filter having an aperture of 1 μm. Then, the filtered material was observed with an optical microscope (× 200), and the number of foreign substances having a major axis of 50 μm or more was counted.

4. Surface Defects of Biaxially Stretched Film The surface of 1 g of the obtained biaxially stretched film was observed with a polarizing microscope, the number of foreign substances having a major axis exceeding 50 μm was measured, and the surface defects of the film were evaluated according to the following criteria. ◎: No number of foreign substances whose major axis exceeds 50 μm per 1 g of biaxially stretched film ○: Number of foreign substances whose major axis exceeds 50 μm per 1 g of biaxially oriented film 1 to 5 △: Per 1 g of biaxially oriented film 6 to 10 foreign substances whose major axis exceeds 50 μm ×: 10 or more foreign substances whose major axis exceeds 50 μm per 1 g of biaxially stretched film

5. Hue 160 ° C. × 60 minutes Heat treatment in a dryer and dried polyester chip hue, color difference meter Z, manufactured by Nippon Denshoku Industries Co., Ltd.
Measured at -1001 DP.

Examples 1-3 Using 100 parts of dimethyl naphthalene-2,6-dicarboxylate and 46.7 parts of 1,3-propanediol, and 0.0055 parts of tetrabutoxytitanate as a transesterification catalyst, After transesterification according to a conventional method, 0.0086 parts of trimethyl phosphate was added to substantially terminate the transesterification reaction.

Next, amorphous germanium dioxide was added as a polymerization catalyst so that the amount of germanium metal in the polymer became the amount shown in Table 1, followed by a polycondensation reaction under a high temperature and high vacuum by a conventional method. Poly- (1,3-propylene) -2,6-naphthalate was obtained. The quality of this polymer was as shown in Table 1.

After drying the polyester pellet at 160 ° C. for 4 hours, it was supplied to an extruder popper and melted at a melting temperature of 25 ° C.
Melted at 0 ° C, surface temperature of 40 ° C through slit die
To obtain an unstretched film.
Next, the unstretched film was preheated to 80 ° C., heated to 110 ° C. by an IR heater between rolls rotating at low speed and high speed, and stretched 3.0 times in the machine direction. Subsequently, the film was supplied to a stenter, stretched 3.3 times in the transverse direction at 110 ° C., and the obtained biaxially oriented film was heat-set at a temperature of 145 ° C. for 5 seconds to obtain a polyester film having a film thickness of 25 μm. The evaluation results of the surface defects of the obtained polyester film were as shown in Table 1.

Comparative Examples 1 and 2 100 parts of dimethyl naphthalene-2,6-dicarboxylate and 46.7 parts of 1,3-propanediol were used, and 0.03 part of manganese acetate tetrahydrate was used as a transesterification catalyst. After transesterification according to a conventional method, trimethyl phosphate 0.023 was added.
Then, the transesterification reaction was substantially terminated.

Next, antimony trioxide was added as a polymerization catalyst so that the amount of antimony metal in the polymer became the amount shown in Table 1, and the polymerization was continued at a polymerization temperature shown in Table 1 at high temperature and high vacuum by a conventional method. After the condensation reaction, the poly- (1,3-
(Propylene) -2,6-naphthalate was obtained. The quality of this polymer was as shown in Table 1.

The obtained polymer was formed into a film in the same manner as in Example 1 to obtain a polyester film having a thickness of 25 μm. Table 1 shows the evaluation results of the surface defects of the obtained polyester film.
Was as shown in FIG.

[0038]

[Table 1]

As is clear from the results shown in Table 1, the polyester film of the present invention has a good hue, a small number of foreign substances, and is excellent in surface properties.

[0040]

The polyester composition of the present invention has good gas barrier properties and hue, and has little foreign matter. Further, the polyester film of the present invention has good gas barrier properties and hue, and has few surface defects, and is useful as a film for various packaging materials.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 67:00 B29L 7:00 F term (Reference) 4F071 AA45 AF08 AF34Y AF57 BB06 BB08 BC01 4F210 AA24 AB16 AE01 AG01 QA02 QA03 QC05 QC06 QG01 QG18 QW07 4J002 CF081 DE096 FD206 4J029 AA03 AB01 AB04 AC02 AD01 AE01 AE02 AE03 BA02 BA03 BA04 BA10 BB04B BB13A BD06A BH02 CB04A CB05A CB06A CB10J05CC06 KB05 JA06

Claims (3)

[Claims] 1. A polyester composition containing naphthalenedicarboxylic acid as a main dicarboxylic acid component, 1,3-propanediol as a main glycol component, and a germanium compound in an amount of 30 to 400 ppm in terms of germanium atoms. 2. The polyester composition according to claim 1, wherein the L value and the b value measured by the Lab method satisfy the following formulas (1) and (2). [Expression 1] 65 ≦ L−b (1) b ≦ 8 (2) 3. A polyester film obtained by melt-extruding the polyester composition according to claim 1 or 2 into a sheet and then biaxially stretching the film.