JPH08283551A - Polyester resin composition - Google Patents

Abstract

PURPOSE: To obtain a polyester resin compsn. which has not only excellent clarity and gas barrier properties but also an improved heat resistance. CONSTITUTION: This compsn. comprises 20-95 pts.wt. polyethylene terephthalate and 80-5 pts.wt. polyethylene 2,6-naphthalenedicarboxylate, and the ratio of the melt viscosity of the latter polymer to the former polymer at their melt mixing temp. is 0.0001-1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester resin composition having excellent transparency. More specifically, it relates to a polyester resin composition capable of forming a film, a container or the like having improved gas barrier properties, heat resistance and the like without impairing transparency.

[0002]

BACKGROUND OF THE INVENTION Polyethylene terephthalate is widely used as a raw material for fibers, films, bottles and the like because of its excellent properties. In particular, in the field of packaging films and bottles for foods, chemicals, cosmetics, etc., in addition to having relatively good gas barrier properties, it is also excellent in melt moldability, transparency, mechanical strength, and other properties. Therefore, the demand is growing rapidly.

However, in the case where the aroma may be deteriorated by oxygen, such as beer, wine, carbonated drinks, and the like, where it is necessary to prevent the leakage of the filling gas, in addition to the characteristics such as transparency, High gas barrier properties are required. In order to use a container made of polyethylene terephthalate for such an application, it is necessary to increase the thickness of the container so as to have a gas barrier property, but this is not only economically disadvantageous, but also increases the thickness of the container. Crystallization is likely to occur, and as a result, transparency is reduced, which is not preferable.

Conventionally, various improvements have been made in order to impart a high gas barrier property to a container or a film using polyethylene terephthalate. For example, attempts have been made to improve the gas barrier property by a multilayer container or a multilayer film combined with polyester or polyamide having a high gas barrier property, or by copolymerization. However, it cannot be said that these methods completely solve the problems of the wall thickness of the container and the gas barrier property.

In addition to these methods, polyethylene terephthalate and polyethylene having a high gas barrier property are used.
Attempts have been made to improve gas barrier properties and various properties such as heat resistance by melt-mixing with 2,6-naphthalenedicarboxylate.
However, the gas barrier property can be improved by melt-mixing polyethylene-2,6-naphthalenedicarboxylate, but polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate have poor compatibility. Therefore, it is difficult to obtain a composition having excellent transparency. Conventionally, in order to solve this problem, attempts have been made to improve transparency by using a compatibilizer or the like, or to improve transparency by causing an ester exchange reaction.

For example, in Japanese Patent Laid-Open No. 2-274757,
It is disclosed that a polyester resin composition capable of forming a stretched bottle having excellent transparency and heat resistance can be obtained by adding a pre-kneaded product of both to a composition composed of polyethylene terephthalate and polyethylene naphthalate. Has been done. Further, in Japanese Patent Laid-Open No. 4-168148,
A polyester resin composition comprising polyethylene terephthalate having a specific intrinsic viscosity and copolymerized polyethylene naphthalate having a specific refractive index and having improved gas barrier properties without impairing transparency is disclosed. However, the melt viscosity of polyethylene terephthalate and polyethylene-
The melt viscosity of 2,6-naphthalenedicarboxylate,
No attention was paid to the correlation of the transparency of the molten mixture.

[0007]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide a polyester resin composition having improved gas barrier properties and heat resistance without impairing transparency. is there.

[0008]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that in a polyester resin composition comprising polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate,
Polyethylene terephthalate and polyethylene-2,6-
It was found that a polyester resin composition having excellent transparency can be obtained by adjusting the melt viscosity ratio of naphthalene dicarboxylate to a specific ratio.

That is, the present invention is a resin composition comprising 20 to 95 parts by weight of polyethylene terephthalate and 80 to 5 parts by weight of polyethylene-2,6-naphthalene dicarboxylate, and the temperature at which both are melt mixed. In the above, the ratio of melt viscosity (melt viscosity of polyethylene-2,6-naphthalenedicarboxylate / melt viscosity of polyethylene terephthalate) is 0.0001 or more and 1 or less, It is an invention related to.

The melt viscosity as referred to in the present invention means a flow tester at a temperature at which polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate used for mixing in producing the above polyester resin composition are melt mixed. (Manufactured by Shimadzu Corporation, model: C
FT-500) is a melt viscosity at a shear rate of 100 s ^-1 measured using a die having a diameter of 1 mm and a length of 10 mm.

The polyethylene terephthalate used in the present invention may contain small amounts of other ester-forming units to the extent that their properties are not essentially changed. That is, the polyethylene terephthalate used in the present invention may contain other ester forming units in an amount of 20 mol% or less, preferably 10 mol% or less, in addition to the ethylene terephthalate unit.

Examples of the dicarboxylic acid and diol constituting the other ester-forming unit include phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 3,4'-diphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
Aromatic dicarboxylic acids such as 2,7-naphthalenedicarboxylic acid, etc., or aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, dodecanedioic acid, etc., or 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexane Alicyclic dicarboxylic acids such as dicarboxylic acids, decalin dicarboxylic acids, tetralin dicarboxylic acids, etc., and propylene glycol, trimethylene glycol,
Aliphatic glycols such as diethylene glycol and 1,4-butanediol, or 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol,
Suitable examples include alicyclic glycols such as 1,6-cyclohexanediol and the like, and aromatic glycols such as bisphenol A and the like.

The polyethylene terephthalate may be capped at its molecular end with a monofunctional compound such as a small amount of benzoic acid, benzoylbenzoic acid, benzyloxybenzoic acid or methoxypolyethylene glycol. In addition, glycerin, trimesic acid,
It may contain a very small amount of a polyfunctional compound such as pentaerythritol.

The polyethylene terephthalate used in the present invention is preferably dried so that the water content in the polymer is 300 ppm or less, preferably 100 ppm or less, more preferably 50 ppm or less, and the melt viscosity is 285.
20 to 5000 Pa · s at 100 ° C., preferably 100
It is desirable that the range is up to 3000 Pa · s. The polyester resin composition using polyethylene terephthalate having a melt viscosity of less than 20 Pa · s may not show sufficient mechanical performance in its molded product.

When polyethylene terephthalate having a melt viscosity of more than 5000 Pa · s is used, since the melt viscosity is too high, mechanical mixing at the time of melt mixing with polyethylene-2,6-naphthalenedicarboxylate is performed. It is difficult to proceed and is not preferable as the material of the present invention.

Polyethylene-2,6 used in the present invention
The naphthalenedicarboxylate may contain small amounts of other ester-forming units, to the extent that their properties are not essentially changed. That is, the polyethylene-2,6-naphthalene dicarboxylate used in the present invention is
In addition to the ethylene-2,6-naphthalenedicarboxylate unit, other ester forming units may be contained in an amount of 20 mol% or less, preferably 10 mol% or less.

Examples of the dicarboxylic acid and diol constituting the other ester forming unit include phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid,
1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,
Aromatic dicarboxylic acids such as 4'-diphenyldicarboxylic acid and 3,4'-diphenyldicarboxylic acid, or aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and dodecanedioic acid, and 1,4-cyclohexane Alicyclic dicarboxylic acids such as dicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, decalindicarboxylic acid, tetralindicarboxylic acid and the like, and aliphatic glycols such as propylene glycol, trimethylene glycol, diethylene glycol, 1,4-butanediol and the like, Or 1,3-cyclohexanedimethanol, 1,
Suitable examples include alicyclic glycols such as 4-cyclohexanedimethanol and 1,6-cyclohexanediol, and aromatic glycols such as bisphenol A.

Further, the above-mentioned polyethylene-2,6
Naphthalene dicarboxylates are, for example, small amounts of benzoic acid, benzoylbenzoic acid, benzyloxybenzoic acid,
The molecular end may be blocked with a monofunctional compound such as methoxypolyethylene glycol. Further, it may contain a very small amount of a polyfunctional compound such as glycerin, trimesic acid and pentaerythritol.

The polyethylene-2,6-naphthalenedicarboxylate used in the present invention is preferably dried to a water content in the polymer of 300 ppm or less, preferably 100 ppm or less, more preferably 50 ppm or less, and has a melt viscosity of 0.1-500 at 285 ° C
It is desirable that the range is 0 Pa · s, preferably 1 to 3000 Pa · s.

In addition to the above-mentioned polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate, a matting agent, a heat resistance stabilizer, a weather resistance stabilizer, a lubricant and the like are added to the polyester resin composition of the present invention. An agent may be included.

In the polyester resin composition composed of polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate as described above, polyethylene terephthalate is added in an amount of 20 to 95 parts by weight, preferably 30 to 90 parts by weight. 80 to 5 parts by weight, preferably 70 to 10 parts by weight, of -2,6-naphthalenedicarboxylate is used.

In the present invention, the melt viscosity ratio (polyethylene-2,6-naphthalene dicarboxylate melt viscosity / polyethylene terephthalate melt viscosity) of the above polyester resin composition when both resins are melt mixed is:
It is necessary to be 0.0001 or more and 1 or less. When the melt viscosity ratio is larger than 1, the polyester resin composition having excellent transparency, which is the object of the present invention, cannot be obtained. When the melt viscosity ratio is less than 0.0001, the performance of the film, bottle, etc. obtained from the polyester resin composition is poor and it cannot be put to practical use. The resin composition obtained by melt mixing at the above melt viscosity ratio is T
When formed into a film by a die method or the like, haze (JI
(Measured by SK7105) is 15% or less, and further 1
A film of 0% or less can be easily obtained.

The method for producing the polyester resin composition of the present invention is carried out by mixing the above-mentioned polyethylene terephthalate and the above-mentioned polyethylene-2,6-naphthalene dicarboxylate in a solid state, and then using a single-screw extruder, a twin-screw extruder, a kneader, etc. It is possible to apply a conventionally known method of melt-mixing with. In order to obtain an actual molded product, it is possible to use a method in which the polyester resin composition once melt-mixed with an extruder or the like is made into pellets and then the target molded product is obtained by using a device such as an extruder or an injection molding machine. The effect of the present invention is most manifested in the case where the polyethylene terephthalate and the polyethylene-2,6-naphthalene dicarboxylate are mixed in a solid state and then melt-processed to directly obtain a desired molded article. To be done.

The polyester resin composition of the present invention is a non-stretched or low-stretched stretched monolayer film or multi-layered film obtained by the T-die method, coextrusion method or the like, a film obtained by stretching them, and a non-stretched state after molding. Direct blow molding containers, low draw ratio deep drawing molding, and containers obtained by stretch blow molding maintain excellent transparency, so moldings such as films, sheets, containers, fibers, etc. Can be used as a body material.

[0025]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The evaluation methods used in the examples and comparative examples are as follows.

(1) Moisture content measuring device: Mitsubishi Kasei Co., Ltd., trace moisture measuring device
Model: CA-05 (2) Melt viscosity measuring device: Shimadzu Corporation, flow tester Model: CFT-500 Die: diameter 1 mm, length 10 mm, shear rate: 100 s
^-1 (3) Haze According to JIS K7105. Measuring device: Nippon Denshoku Industries Co., Ltd., color difference meter Model: Z-
Σ80

Example 1 Polyethylene terephthalate (hereinafter sometimes referred to as PET) pellets (melt viscosity 2400 Pa · s, measurement temperature 285 ° C., water content 20 ppm) and polyethylene-2,6-naphthalene dicarboxylate (hereinafter PE)
N pellets (melt viscosity 480Pa
・ S, a measurement temperature of 285 ° C., and a water content of 35 ppm were mixed by a tumbler, and a mixed pellet having a blend ratio (PET / PEN, weight ratio) of 80/20 (melt viscosity ratio: 0.
20) was prepared.

Immediately after mixing the mixed pellets, using a single screw extruder (screw diameter: 20 mm, L / D: 25, screw type: full flight), a cylinder temperature of 275 to 285 ° C. and a T die temperature of 285 were measured by the T die method. ℃,
Melt mixing was performed under the conditions of a screw rotation speed of 72 rpm and a cooling roll temperature of 90 ° C. to obtain a film having a width of 120 mm and a thickness of 31 μm. Table 1 shows the raw material composition and the haze measurement result of the obtained film.

Example 2 Polyethylene terephthalate pellets (melt viscosity 72
0 Pa · s, measuring temperature 285 ° C., water content 27 ppm) and polyethylene-2,6-naphthalene dicarboxylate pellets (melt viscosity 400 Pa · s, measuring temperature 2)
85 ° C., water content 38 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 80 /
20 mixed pellets (melt viscosity ratio: 0.56) were prepared. Immediately after mixing the mixed pellets, using a single-screw extruder (screw diameter: 20 mm, L / D: 25, screw type: full flight), a cylinder temperature of 275 to 285 ° C., a T-die temperature of 285 ° C., a screw by a T-die method. Melt mixing was carried out under the conditions of a rotation speed of 72 rpm and a cooling roll temperature of 90 ° C. to obtain a film having a width of 120 mm and a thickness of 29 μm. Table 1 shows the raw material composition and the haze measurement result of the obtained film.

Example 3 Polyethylene terephthalate pellets (melt viscosity 15
70 Pa · s, measurement temperature 285 ° C., moisture content 30 ppm)
And polyethylene-2,6-naphthalenedicarboxylate pellets (melt viscosity 1150 Pa · s, measurement temperature 285 ° C., water content 32 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 80.
/ 20 mixed pellets (melt viscosity ratio: 0.73) were prepared.

Immediately after mixing the mixed pellets, using a single screw extruder (screw diameter: 20 mm, L / D: 25, screw type: full flight), the cylinder temperature is 275 to 285 ° C. and the T die temperature is 285 by the T die method. ℃,
Melt mixing was performed under the conditions of a screw rotation speed of 72 rpm and a cooling roll temperature of 90 ° C. to obtain a film having a width of 120 mm and a thickness of 30 μm. Table 1 shows the raw material composition and the haze measurement result of the obtained film.

Example 4 Polyethylene terephthalate pellets (melt viscosity 24
00Pa · s, measurement temperature 285 ° C, moisture content 20ppm)
And polyethylene-2,6-naphthalenedicarboxylate pellets (melt viscosity 480 Pa · s, measurement temperature 285 ° C., water content 35 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 60 /.
40 mixed pellets (melt viscosity ratio: 0.20) were prepared.

From the mixed pellets stored without moisture absorption, a single-screw extruder (screw diameter: 20 m
m, L / D: 25, screw type: full flight), cylinder temperature 275-285 by T-die method
℃, T die temperature 285 ℃, screw rotation speed 72 rp
m, chill roll temperature 90 ° C, melt-mixed, width 1
A film having a thickness of 20 mm and a thickness of 30 μm was obtained. Table 1 shows the raw material composition and the haze measurement result of the obtained film.

Example 5 Polyethylene terephthalate pellets (melt viscosity 15
70 Pa · s, measurement temperature 285 ° C., moisture content 30 ppm)
And polyethylene-2,6-naphthalenedicarboxylate pellets (melt viscosity 1150 Pa · s, measurement temperature 285 ° C., water content 32 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 60.
A / 40 mixed pellet (melt viscosity ratio: 0.73) was prepared.

From the mixture pellets stored without moisture absorption, a single-screw extruder (screw diameter: 20 m
m, L / D: 25, screw type: full flight), cylinder temperature 275-285 by T-die method
℃, T die temperature 285 ℃, screw rotation speed 72 rp
m, chill roll temperature 90 ° C, melt-mixed, width 1
A film having a thickness of 20 mm and a thickness of 32 μm was obtained. Table 1 shows the raw material composition and the haze measurement result of the obtained film.

Example 6 Polyethylene terephthalate pellets (melt viscosity 24
00Pa · s, measurement temperature 285 ° C, moisture content 20ppm)
And polyethylene-2,6-naphthalenedicarboxylate pellets (melt viscosity 480 Pa · s, measurement temperature 285 ° C., water content 35 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 30 /.
70 mixed pellets (melt viscosity ratio: 0.20) were prepared.

From the mixture pellets stored without moisture absorption, a single-screw extruder (screw diameter: 20 m
m, L / D: 25, screw type: full flight), cylinder temperature 275-285 by T-die method
℃, T die temperature 285 ℃, screw rotation speed 72 rp
m, chill roll temperature 90 ° C, melt-mixed, width 1
A film having a thickness of 20 mm and a thickness of 29 μm was obtained. Table 1 shows the raw material composition and the haze measurement result of the obtained film.

Example 7 Polyethylene terephthalate pellets (melt viscosity 15
70 Pa · s, measurement temperature 285 ° C., moisture content 30 ppm)
And polyethylene-2,6-naphthalenedicarboxylate pellets (melt viscosity 1150 Pa · s, measurement temperature 285 ° C., water content 32 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 30.
A / 70 mixed pellet (melt viscosity ratio: 0.73) was prepared.

From the mixed pellets stored without moisture absorption, a single-screw extruder (screw diameter: 20 m
m, L / D: 25, screw type: full flight), cylinder temperature 275-285 by T-die method
℃, T die temperature 285 ℃, screw rotation speed 72 rp
m, chill roll temperature 90 ° C, melt-mixed, width 1
A film having a thickness of 20 mm and a thickness of 30 μm was obtained. Table 1 shows the raw material composition and the haze measurement result of the obtained film.

Comparative Example 1 Polyethylene terephthalate pellets (melt viscosity 31
0 Pa · s, measuring temperature 285 ° C., water content 25 ppm, and polyethylene-2,6-naphthalene dicarboxylate pellets (melt viscosity 400 Pa · s, measuring temperature 2)
85 ° C., water content 38 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 80 /
20 mixed pellets (melt viscosity ratio: 1.29) were prepared.

Immediately after mixing the mixed pellets, using a single-screw extruder (screw diameter: 20 mm, L / D: 25, screw type: full flight), a cylinder temperature of 275 to 285 ° C. and a T-die temperature of 285 were measured by the T-die method. ℃,
The mixture was melt-mixed under the conditions of a screw rotation speed of 72 rpm and a cooling roll temperature of 90 ° C. to obtain a film having a width of 120 mm and a thickness of 30 μm. Table 2 shows the raw material composition and the haze measurement result of the obtained film.

Comparative Example 2 Polyethylene terephthalate pellets (melt viscosity 11
0 Pa · s, measuring temperature 285 ° C., moisture content 29 ppm) and polyethylene-2,6-naphthalene dicarboxylate pellets (melt viscosity 450 Pa · s, measuring temperature 2)
85 ° C., water content 25 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 80 /
20 mixed pellets (melt viscosity ratio: 4.09) were prepared.

Immediately after mixing the mixed pellets, using a single screw extruder (screw diameter: 20 mm, L / D: 25, screw type: full flight), the cylinder temperature is 275 to 285 ° C. and the T die temperature is 285 by the T die method. ℃,
The mixture was melt-mixed under the conditions of a screw rotation speed of 72 rpm and a cooling roll temperature of 90 ° C. to obtain a film having a width of 120 mm and a thickness of 31 μm. Table 2 shows the raw material composition and the haze measurement result of the obtained film.

Comparative Example 3 Polyethylene terephthalate pellets (melt viscosity 31
0 Pa · s, measuring temperature 285 ° C., water content 25 ppm, and polyethylene-2,6-naphthalene dicarboxylate pellets (melt viscosity 400 Pa · s, measuring temperature 2)
85 ° C., water content 38 ppm) was mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 60 /
40 mixed pellets (melt viscosity ratio: 1.29) were prepared.

From the mixture pellets stored without moisture absorption, a single-screw extruder (screw diameter: 20 m
m, L / D: 25, screw type: full flight), cylinder temperature 275-285 by T-die method
℃, T die temperature 285 ℃, screw rotation speed 72 rp
m, chill roll temperature 90 ° C, melt-mixed, width 1
A film having a thickness of 20 mm and a thickness of 31 μm was obtained. Table 2 shows the raw material composition and the haze measurement result of the obtained film.

Comparative Example 4 Polyethylene terephthalate pellets (melt viscosity 31
0 Pa · s, measuring temperature 285 ° C., water content 25 ppm, and pellets of polyethylene-2,6-naphthalene dicarboxylate (melt viscosity 950 Pa · s, measuring temperature 2)
85 ° C., water content 31 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 60 /
40 mixed pellets (melt viscosity ratio: 3.06) were prepared.

From the mixed pellets stored without moisture absorption, a single-screw extruder (screw diameter: 20 m
m, L / D: 25, screw type: full flight), cylinder temperature 275-285 by T-die method
℃, T die temperature 285 ℃, screw rotation speed 72 rp
m, chill roll temperature 90 ° C, melt-mixed, width 1
A film having a thickness of 20 mm and a thickness of 30 μm was obtained. Table 2 shows the raw material composition and the haze measurement result of the obtained film.

Comparative Example 5 Polyethylene terephthalate pellets (melt viscosity 31
0 Pa · s, measuring temperature 285 ° C., water content 25 ppm, and polyethylene-2,6-naphthalene dicarboxylate pellets (melt viscosity 400 Pa · s, measuring temperature 2)
85 ° C., moisture content 38 ppm) were mixed by a tumbler, and the blend ratio (PET / PEN, weight ratio) was 30 /
70 mixed pellets (melt viscosity ratio: 1.29) were prepared.

From the mixture pellets stored without moisture absorption, a single-screw extruder (screw diameter: 20 m
m, L / D: 25, screw type: full flight), cylinder temperature 275-285 by T-die method
℃, T die temperature 285 ℃, screw rotation speed 72 rp
m, chill roll temperature 90 ° C, melt-mixed, width 1
A film having a thickness of 20 mm and a thickness of 32 μm was obtained. Table 2 shows the raw material composition and the haze measurement result of the obtained film.

[0050]

The polyester resin composition of the present invention has excellent transparency and is useful as a material for films, sheets, containers, fibers and the like.

Table 1 Example No. PEN blend amount (parts by weight) Melt viscosity ratio * Haze (%) 1 20 0.20 5.7 2 20 0.56 13.6 3 20 0.73 8.1 4.1 40 40 .20 11.6 5 40 0.73 13.0 6 70 0.20 13.8 7 70 0.73 12.5 Note) *: PEN melt viscosity / PET melt viscosity

Table 2 Comparative Example No. PEN blend amount (parts by weight) Melt viscosity ratio * Haze (%) 1 20 1.29 27.7 2 20 4.09 43.7 3 40 1.29 23.7 4 40 3 0.06 24.3 5 70 1.29 17.5 Note) *: PEN melt viscosity / PET melt viscosity

Claims (2)

[Claims] 1. Polyethylene terephthalate 20-95
A resin composition comprising 1 part by weight and 80 to 5 parts by weight of polyethylene-2,6-naphthalene dicarboxylate, the ratio of melt viscosity at the temperature when the two are melt mixed (polyethylene-2,6-naphthalene). A polyester resin composition characterized in that the melt viscosity of dicarboxylate / the melt viscosity of polyethylene terephthalate is 0.0001 or more and 1 or less. 2. The polyester resin composition according to claim 1, which has a haze of 15% or less when formed into a film having a thickness of 30 μm.