JP2001031852A - Polyethylene terephthalate-based resin composition having excellent transparency and impact resistance, its production and holding product comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyethylene terephthalate-based resin composition having excellent both transparency and impact resistance. SOLUTION: This polyethylene terephthalate-based resin composition comprises a polyethylene terephthalate-based resin (A) and a core-shell polymer (B) satisfying conditions of (1) having a three-layer structure composed of a core layer constituted of a polymer consisting essentially of a styrene-based compound, a middle layer composed of a polymer consisting essentially of a 2-8C alkyl group-containing alkyl acrylate and a shell layer composed of a polymer consisting essentially of methyl methacrylate, (2) having >=10 wt.% middle layer content based on the total of the core layer, the middle layer and the shell layer, (3) having <=170 nm particle diameter of the core layer, (4) having <=15 nm the sum of the thickness of the middle layer and the shell layer and (5) having <=0.020 absolute value of difference in refractive index between the polyethylene terephthalate-based resin (A) and the core-shell polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyethylene terephthalate resin composition comprising a polyethylene terephthalate resin containing a specific core-shell polymer, a method for producing the polyethylene terephthalate resin composition,
The present invention relates to a molded article comprising the polyethylene terephthalate resin composition and a core-shell polymer suitable for producing the polyethylene terephthalate resin composition. The polyethylene terephthalate-based resin composition of the present invention has significantly improved impact resistance as compared with the polyethylene terephthalate-based resin, while maintaining the transparency of the polyethylene terephthalate-based resin at a high level. Therefore, a molded article made of the polyethylene terephthalate resin composition,
These excellent performances can be effectively exhibited.
Further, the core-shell polymer of the present invention is useful for producing a polyethylene terephthalate-based resin composition having such excellent performance.

[0002]

2. Description of the Related Art Polyethylene terephthalate resin represented by polyethylene terephthalate has good transparency but is inferior in impact resistance. Therefore, a polyethylene terephthalate resin has a multilayer structure comprising a core layer and one or more layers covering the core layer. Attempts have been made to improve the impact resistance by blending structural polymer particles (so-called core-shell polymers). However, when a core-shell polymer is blended, the original transparency of the polyethylene terephthalate resin is usually greatly impaired, and it is extremely limited that both good transparency and improved impact resistance are compatible. Have been. As a polyethylene terephthalate-based resin composition having both good transparency and improved impact resistance, JP-A-10-101917 discloses a core layer made of a rubber-like polymer and a shell layer made of a glass-like polymer. There has been proposed a polyethylene terephthalate-based resin composition obtained by blending a specific two-layered core-shell polymer with a polyethylene terephthalate-based resin. In the resin composition, it is necessary that the refractive index of the polyethylene terephthalate resin, the refractive index of the rubbery polymer forming the core layer, and the refractive index of the glassy polymer forming the shell layer satisfy specific conditions.

Japanese Patent Application Laid-Open No. 6-145263 does not mention polyethylene terephthalate resin, but includes poly (methyl methacrylate-styrene) resin, poly (acrylonitrile-methyl methacrylate-styrene) resin, and polymethyl methacrylate. For a transparent thermoplastic resin such as a resin, a thermoplastic resin composition containing a specific core-shell polymer having a core layer made of a rubbery polymer and a shell layer made of a glassy styrene-based polymer maintains good transparency. While improving the impact resistance. In the thermoplastic resin composition, the absolute value of the difference in the refractive index between the thermoplastic resin and the entire core-shell polymer is 0.0%.
The refractive index of the thermoplastic resin, such as less than 0.05, the difference in the refractive index between the glassy polymer constituting the shell layer and the rubbery polymer constituting the core layer is 0.06 or less; It is necessary that the entire refractive index, the refractive index of the rubbery polymer constituting the core layer, and the refractive index of the glassy polymer constituting the shell layer satisfy specific conditions.

[0004]

The above-mentioned Japanese Patent Application Laid-Open No. 10-10 / 1998
In the polyethylene terephthalate-based resin composition described in Japanese Patent No. 1917, the refractive index of the polyethylene terephthalate-based resin is specifically high at about 1.567 to 1.580. The selection range is relatively narrow. For example, in this publication, a copolymer of a conjugated diene compound such as butadiene and an aromatic methacrylate such as phenyl methacrylate and / or an aromatic vinyl compound such as styrene is recommended as the rubbery polymer constituting the core layer, As a glassy polymer constituting the layer, a homopolymer or copolymer of methyl methacrylate or styrene is recommended. However, a polymer having a chemical structure derived from a conjugated diene compound is inferior in weather resistance, so when excellent weather resistance is required for the obtained polyethylene terephthalate-based resin composition,
The incorporation of a core-shell polymer obtained using a conjugated diene compound as described above is undesirable. The present inventors have also attempted to apply the technique of a thermoplastic resin composition comprising a thermoplastic resin and a specific core-shell polymer as described in JP-A-6-145263 to a polyethylene terephthalate-based resin. However, it was difficult to achieve both transparency and impact resistance due to the specific high refractive index of the polyethylene terephthalate resin. That is, in a core-shell polymer having a core layer made of a rubber-like polymer and a shell layer made of a glassy styrene-based polymer, the difference in the refractive index between the styrene-based polymer constituting the shell layer and the polymer constituting the core layer is reduced, And when trying to approach the refractive index of the entire core-shell polymer to the high refractive index of the polyethylene terephthalate-based resin, in order to increase the refractive index of the core layer, the use ratio of the styrene-based compound in the monomers constituting the polymer of the layer is reduced. Although it has to be increased, increasing the use ratio of the styrene compound for forming the core layer causes a disadvantage that the rubber property of the core layer is reduced, and the core-shell polymer loses the effect of improving the impact resistance. It has been found.

An object of the present invention is to provide a polyethylene terephthalate-based resin which is excellent in both transparency and impact resistance by blending a core-shell polymer which can be produced without using a conjugated vinyl compound as a raw material for polymerization with a polyethylene terephthalate-based resin. It is to provide a resin composition. Another object of the present invention is to provide a method for producing the polyethylene terephthalate resin composition. Another object of the present invention is to provide a molded article in which the features of the polyethylene terephthalate resin composition are effectively exhibited.
Still another object of the present invention is to provide a core-shell polymer suitable for producing the polyethylene terephthalate-based resin composition.

[0006]

Means for Solving the Problems Accordingly, the present inventors have
When combined with polyethylene terephthalate resin,
As a result of intensive research on a core-shell polymer capable of providing a polyethylene terephthalate-based resin composition having both excellent transparency and impact resistance, a core layer composed of a monomer polymer mainly composed of a styrene-based compound, It has a three-layer structure including an intermediate layer composed of a polymer of a monomer mainly composed of alkyl acrylate and a shell layer composed of a polymer of a monomer mainly composed of methyl methacrylate, and the content of the intermediate layer, The above problem is solved by using a core-shell polymer that satisfies predetermined conditions for the particle diameter of the core layer, the sum of the thicknesses of the intermediate layer and the shell layer, and the refractive index difference between the polyethylene terephthalate-based resin. And completed the present invention.

According to the present invention, one of the above-mentioned problems is that the polyethylene terephthalate resin (A) and the following conditions (1) to (5):

(1) A core layer made of a polymer of a monomer mainly composed of a styrene compound, wherein the alkyl group has 2 to 2 carbon atoms.
8 having a three-layer structure composed of an intermediate layer composed of a polymer of a monomer mainly composed of an alkyl acrylate and a shell layer composed of a polymer of a monomer mainly composed of methyl methacrylate;

(2) The content of the intermediate layer is 1 based on the entire core layer, the intermediate layer and the shell layer.
0% by weight or more;

(3) The particle size of the core layer is 170 nm or less;

(4) The sum of the thicknesses of the intermediate layer and the shell layer is 15 nm or less;

(5) The absolute value of the difference in the refractive index between the polyethylene terephthalate resin (A) and the polyethylene terephthalate resin (A) is 0.0
Not more than 20;

The problem is solved by providing a polyethylene terephthalate resin composition comprising a core-shell polymer (B) satisfying all of the above.

According to the present invention, another object of the present invention is to provide a polyethylene terephthalate resin composition characterized by mixing a polyethylene terephthalate resin (A) with the core-shell polymer (B) under melting conditions. The problem is solved by providing a method of manufacturing a product.

According to the present invention, another object of the present invention is attained by providing a molded article comprising the above-mentioned polyethylene terephthalate resin composition.

According to the present invention, another one of the above-mentioned problems is as follows.

(1) A core layer made of a polymer of a monomer mainly composed of a styrene compound, wherein the alkyl group has 2 to 2 carbon atoms.
8, which has a three-layer structure composed of an intermediate layer composed of a polymer of a monomer mainly composed of an alkyl acrylate and a shell layer composed of a polymer of a monomer mainly composed of methyl methacrylate;

(2) The content of the intermediate layer is 1 based on the whole of the core layer, the intermediate layer and the shell layer.
0% by weight or more;

(3) The particle size of the core layer is 170 nm or less;

(4) the sum of the thicknesses of the intermediate layer and the shell layer is 15 nm or less; and

(5) The problem is solved by providing a core-shell polymer having a refractive index in the range of 1.547 to 1.574.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In the polyethylene terephthalate resin composition of the present invention, a polyethylene terephthalate resin (A) is a polyester resin having an ethylene terephthalate unit as a main repeating unit (that is, a terephthalic acid unit and an ethylene glycol unit). Polyester resin having a main structural unit),
Polyethylene terephthalate resins and copolyester resins having a chemical structure in which a small amount of a copolymer component is incorporated in the molecular chain of polyethylene terephthalate are included. Examples of the dicarboxylic acid unit other than the terephthalic acid unit that the polyethylene terephthalate-based resin (A) can contain as a copolymer component include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, Aromatic dicarboxylic acids such as bis (p-carboxyphenyl) methane, anthracenedicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, and sodium 5-sulfoisophthalate; fats such as adipic acid, sebacic acid, azelaic acid, dodecanedioic acid Group dicarboxylic acids;
Alicyclic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; and dicarboxylic acids derived from ester-forming derivatives thereof (lower alkyl esters such as methyl ester and ethyl ester). Units can be mentioned. Examples of the diol unit other than the ethylene glycol unit which the polyethylene terephthalate resin (A) may contain as a copolymer component include propylene glycol, neopentyl glycol, 2-methylpropanediol, 1,5-pentanediol, and cyclohexane dimethanol. , An aliphatic diol having 2 to 10 carbon atoms such as cyclohexanediol; diethylene glycol, polyethylene glycol,
Examples thereof include diol units derived from polyalkylene glycol having a molecular weight of 6000 or less, such as poly-1,3-propylene glycol and polytetramethylene glycol. Further, the polyethylene terephthalate resin (A) may be used in a small amount such as 1 mol% or less based on all structural units, for example, glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, pyromellitic acid, etc. It may have a structural unit derived from a tri- or higher functional monomer as a copolymer component. When the polyethylene terephthalate-based resin (A) is a copolyester resin, the above copolymer component is 1
There may be only one kind or two or more kinds.

Polyethylene terephthalate resin (A)
Is not necessarily limited, and suitable conditions can be appropriately selected according to the intended use of the obtained polyethylene terephthalate resin composition. For example, if the obtained polyethylene terephthalate-based resin composition is used in the form of a molded article, the intrinsic viscosity of the polyethylene terephthalate-based resin (A) used for preparing the composition is usually 0.4 to 1 .6dl
/ G is preferable.

In the polyethylene terephthalate-based resin composition of the present invention, the polyethylene terephthalate-based resin (A) may be one kind of polyethylene terephthalate-based resin, or two or more kinds differing in chemical structure, intrinsic viscosity and the like. A mixture of polyethylene terephthalate resins may be used. Therefore, the polyethylene terephthalate resin (A) may be a mixture of a crystalline polyethylene terephthalate resin and an amorphous polyethylene terephthalate resin. When the polyethylene terephthalate-based resin (A) is a mixture of two or more kinds of polyethylene terephthalate-based resins having different intrinsic viscosities, the intrinsic viscosity of the polyethylene terephthalate-based resin (A) can be evaluated by the intrinsic viscosity of the mixture. it can.

In the polyethylene terephthalate resin composition of the present invention, a specific core-shell polymer (B) is used together with the polyethylene terephthalate resin (A).
Is used. As used herein, the term “core-shell polymer” refers to a multilayered polymer particle composed of a core layer and one or more layers covering the core layer, wherein adjacent layers are composed of different types of polymers. I do.

The core-shell polymer (B) satisfies all of the following conditions (1) to (5).

(1) A core layer (innermost layer) composed of a polymer of a monomer mainly composed of a styrene compound, and a polymer layer mainly composed of an alkyl acrylate having an alkyl group having 2 to 8 carbon atoms. A core-shell polymer having a three-layer structure composed of an intermediate layer made of a coalescence and a shell layer (outermost layer) made of a monomer polymer mainly composed of methyl methacrylate.

(2) The content of the intermediate layer is 1 based on the entire core layer, the intermediate layer and the shell layer.
0% by weight or more.

(3) The particle size of the core layer is 170 nm or less.

(4) The sum of the thicknesses of the intermediate layer and the shell layer is 15 nm or less.

(5) The absolute value of the difference in refractive index between the resin and the polyethylene terephthalate resin (A) is 0.020.
The core-shell polymer is as follows.

First, the above condition (1) will be described.

The core layer of the core-shell polymer (B) is composed of a monomer polymer mainly composed of a styrene compound. Since a monomer polymer mainly composed of a styrene-based compound has a relatively high refractive index, it has a function of making the refractive index of the entire core-shell polymer (B) close to that of the polyethylene terephthalate-based resin (A). The polymer constituting the core layer may be non-uniformly dispersed in chemical structure within the core layer as long as the polymer is a monomer polymer mainly composed of a styrene-based compound. Thus, for example, the core layer may be composed of a plurality of polymer layers that differ in the type and / or content of the comonomer,
Further, the content of the comonomer in the polymer in the core layer may be continuously changed and distributed according to the distance from the center of the core-shell polymer.

The monomer mainly composed of a styrene-based compound suitable for forming the polymer constituting the core layer may be a styrene-based compound alone or another monomer capable of copolymerizing the styrene-based compound with the styrene-based compound. And the case where it is combined with a monomer. The styrene-based compound is preferably used in a proportion of 50% by weight or more of all monomers used for forming the polymer of the core layer. Examples of the styrene-based compound include aromatic monovinyl compounds such as styrene, vinyltoluene and α-methylstyrene, and aromatic polyvinyl compounds such as divinylbenzene, among which styrene and divinylbenzene are preferable. The weight ratio of the aromatic monovinyl compound / aromatic polyvinyl compound in the styrene compound is preferably in the range of 40/60 to 100/0.

Other monomers copolymerizable with the styrene compound include, for example, alkyl acrylates such as butyl acrylate and 2-ethylhexyl acrylate; and alkyl methacrylates such as methyl methacrylate. Other monomers copolymerizable with the styrene compound include, for example, crosslinkable monomers such as alkane polyol polyacrylates such as hexanediol diacrylate; and grafts of unsaturated carboxylic acid allyl esters such as allyl methacrylate. It is also possible to use monomers for use.

In the core-shell polymer (B), in order to form a polymer of the core layer, an appropriate amount of an aromatic polyvinyl compound is used as a part of the styrene-based compound, or other polymer which can be copolymerized with the styrene-based compound. By using an appropriate amount of a crosslinkable monomer and / or a grafting monomer as at least a part of the monomer, an appropriate crosslinking density and a grafting ratio are realized in a polymer constituting the core layer,
It is preferable because inconveniences such as a decrease in transparency and a decrease in impact resistance due to breakage of the core-shell structure when the core-shell polymer (B) is mixed with the polyethylene terephthalate resin (A) are suppressed.

When an aromatic polyvinyl compound such as divinylbenzene which can express a particularly high refractive index is used as a part of the styrene compound, the above-mentioned polyethylene terephthalate resin (A) and the core-shell polymer (B) can be used. Not only the inconvenience due to the core-shell structure destruction during mixing is suppressed, but also the refractive index of the core-shell polymer (B) is further increased, and the transparency of the polyethylene terephthalate-based resin composition may be further improved. However, when the aromatic polyvinyl compound is used in an amount exceeding 15.0% by weight of the total monomers used in the polymerization for forming the core layer, two or more polymerizable vinyls are used in the polymerization step for forming the core layer. Aromatic polyvinyl compound molecules that react with only a part of the groups and unreacted polymerizable vinyl groups react with the monomer for forming the intermediate layer in the next polymerization step for forming the intermediate layer (that is, the monomer for grafting). Ratio of the aromatic polyvinyl compound molecule that functions as a monomer) based on all monomers. If the grafting ratio between the core layer and the intermediate layer is too high, the effect of improving the impact resistance of the core-shell polymer may be reduced. In the case of using more than 15.0% by weight of the monomer, for example, the core layer has a two-layer structure composed of a particulate layer on the center side and a layer on the surface side covering the layer. The total ratio of the aromatic polyvinyl compound, the crosslinkable monomer and the grafting monomer in (1) to 10.0% by weight or less of the total monomers used for the polymerization for forming the surface-side layer. May give good results. The core layer having such a two-layer structure is, for example, a part of an aromatic monovinyl compound (for example,
(70.0 to 90.0% by weight of the aromatic monovinyl compound used for forming the core layer) and polymerization of all or most of the aromatic polyvinyl compound to contain structural units derived from the aromatic polyvinyl compound High polymer layer (center side layer), then the remainder of the aromatic monovinyl compound (e.g., 30.0-10.0% by weight of the aromatic monovinyl compound used to form the core layer) and If desired, a polymer layer (surface-side layer) having a low content of structural units derived from the aromatic polyvinyl compound can be formed by polymerization using the remainder of the aromatic polyvinyl compound.

When a crosslinkable monomer and / or a grafting monomer copolymerizable with a styrene compound is used, the crosslinkable monomer and / or the grafting monomer are generally used in the total amount of both. Is preferably used in the range of 0.5 to 15.0% by weight, and more preferably in the range of 1.0 to 10.0% by weight of the total monomers used for the polymerization for forming the core layer. Is more preferred.

The intermediate layer of the core-shell polymer (B) is composed of a polymer of a monomer mainly composed of an alkyl acrylate having an alkyl group having 2 to 8 carbon atoms. The layer gives the core-shell polymer (B) an effect of improving impact resistance by exhibiting rubber-like properties. The polymer constituting the intermediate layer may be non-uniformly distributed in the chemical structure within the intermediate layer as long as the polymer is a monomer polymer mainly composed of the acrylate. Thus, for example, the intermediate layer may be composed of a plurality of polymer layers differing in the type and / or content of the comonomer, and the content of the comonomer in the polymer in the intermediate layer May be continuously changed and distributed according to the distance from the center of the core-shell polymer.

A monomer mainly composed of an alkyl acrylate having an alkyl group having 2 to 8 carbon atoms, which is suitable for forming a polymer constituting the intermediate layer, is composed of the alkyl acrylate alone (a combination of two or more kinds). May be).
And the case where the alkyl acrylate is combined with another monomer copolymerizable therewith. However, when another monomer is used in combination with the alkyl acrylate, the type and the use ratio of the other monomer are within a range where the glass transition temperature of the obtained copolymer is −35 ° C. or less. Is preferred in terms of the effect of improving the impact resistance of the core-shell polymer (B). As the alkyl acrylate having 2 to 8 carbon atoms in the alkyl group,
For example, butyl acrylate, 2-ethylhexyl acrylate and the like can be mentioned. The alkyl acrylate is preferably used in a proportion of at least 85% by weight based on all monomers used for forming the polymer of the intermediate layer. Examples of other monomers copolymerizable with the alkyl acrylate include styrene compounds such as styrene, and methacrylates such as methyl methacrylate, lauryl methacrylate, and phenyl methacrylate.

In the core-shell polymer (B), as the other monomer copolymerizable with the alkyl acrylate, a cross-linkable monomer and / or a monomer for grafting as exemplified for the polymer forming the core layer are used. It is also possible to use the body. The use of an appropriate amount of a crosslinkable monomer and / or a grafting monomer as at least a part of the other monomer copolymerizable with the alkyl acrylate can provide an appropriate amount of crosslinking for the polymer constituting the intermediate layer. It is preferable because the density and the grafting ratio are realized, and the impact resistance of the polyethylene terephthalate resin composition obtained by mixing the core-shell polymer (B) with the polyethylene terephthalate resin (A) can be further increased. In terms of compatibility between transparency and impact resistance, the crosslinkable monomer and / or the grafting monomer, in the total amount of both, are 0.1% of all monomers used for polymerization for forming the intermediate layer. It is preferably used in the range of 25 to 3.0% by weight, and 0.5 to 1.0% by weight.
It is more preferable to use in the range.

The shell layer of the core-shell polymer (B) is
It is composed of a monomer polymer mainly composed of methyl methacrylate. Since a polymer of a monomer mainly composed of methyl methacrylate has good thermoplasticity and good affinity for a polyethylene terephthalate resin, the core-shell polymer (B) is melt-mixed with the polyethylene terephthalate resin (A). Has the function of improving the compatibility of the core-shell polymer (B) and the ease of handling during production and use of the core-shell polymer (B).
Monomers mainly composed of methyl methacrylate suitable for forming a polymer constituting the shell layer include, in the case of methyl methacrylate alone, and the case of combining methyl methacrylate with another monomer copolymerizable therewith. Include. Methyl methacrylate is preferably used in an amount of 70% by weight or more of all monomers used for forming the polymer of the shell layer. Examples of other monomers copolymerizable with methyl methacrylate include alkyl acrylates such as methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; acrylic acid; and methacrylic acid.

When a monomer having a carboxyl group such as acrylic acid or methacrylic acid is used as a comonomer,
When the core-shell polymer (B) is melt-kneaded with the polyethylene terephthalate resin (A), the compatibility is improved, and the uniformity of the dispersed state may be further improved. When melt-kneading the polyethylene terephthalate resin (A) and the core-shell polymer (B), when the viscosity of the polyethylene terephthalate resin (A) used is low,
When a sufficient shearing stress cannot be obtained, for example, when the kneading capacity of the melt kneading apparatus is low, it is particularly effective to make the polymer constituting the shell layer contain a carboxyl group as described above. When a monomer having a carboxyl group such as acrylic acid or methacrylic acid is used, the amount used is in the range of 1.0 to 15.0% by weight of the total monomers used for the polymerization for forming the shell layer. It is preferred to be within.

Next, the condition (2) will be described.

In the core-shell polymer (B), the content of the intermediate layer needs to be 10% by weight or more based on the whole of the core layer, the intermediate layer and the shell layer. When the content of the intermediate layer is less than 10% by weight, the effect of improving the impact resistance of the core-shell polymer becomes weak, and the impact resistance of the polyethylene terephthalate-based resin composition using the same becomes insufficient.

The content of each layer constituting the core-shell polymer (B) is not necessarily limited as long as the conditions (1) to (5) are satisfied, but the resulting polyethylene terephthalate resin composition is not limited. High transparency and impact resistance, easy availability of monomers used for the production of core-shell polymer, easy production operation, easy handling of core-shell polymer, polyethylene terephthalate resin (A) From the viewpoint of ease of melt-kneading, the content of the core layer is selected from the range of 60 to 80% by weight based on the entire core-shell polymer (that is, the entire core layer, intermediate layer and shell layer), The content of the intermediate layer is selected from the range of 10 to 40% by weight, and the content of the shell layer is selected from the range of 0.1 to 10% by weight. Preferred. The content of the shell layer is such that the difference in the refractive index between the polyethylene terephthalate resin (A) and the core-shell polymer (B) is reduced, and the transparency of the resulting polyethylene terephthalate resin composition is improved. Preferably, it is as low as possible. When the content of the shell layer is set low, a part of the intermediate layer of the obtained core-shell polymer may be exposed, but in order to produce the polyethylene terephthalate-based resin composition of the present invention, the core-shell polymer (B) It is also possible to use one in which a part of the intermediate layer is exposed. However, if a part of the core-shell polymer intermediate layer is exposed, the polyethylene terephthalate resin (A)
, The resulting polyethylene terephthalate-based resin composition will have poor dispersibility, and the effect of improving impact resistance will not be easily exhibited. In addition, if a part of the intermediate layer of the core-shell polymer is exposed, the core-shell polymers tend to stick to each other, and the handleability of the core-shell polymer may be reduced. Therefore, regarding the content of the shell layer, the content of the rubber layer, the melt-kneading conditions employed in the production stage of the polyethylene terephthalate-based resin composition and the like are taken into consideration, and the content is within the above range of 0.1 to 10 wt%. It is preferable to select appropriate conditions as appropriate.

Next, the conditions (3) and (4) will be described.

In the core-shell polymer (B), it is necessary that the particle size of the core layer is 170 nm or less, and the sum of the thicknesses of the intermediate layer and the shell layer is 15 nm or less.
When the particle size of the core layer is larger than 170 nm and / or when the total thickness of the intermediate layer and the shell layer is larger than 15 nm, the resulting polyethylene terephthalate-based resin composition has insufficient transparency. From the viewpoint that the transparency of the obtained polyethylene terephthalate resin composition is particularly good, the particle diameter of the core layer is preferably 150 nm or less, or the sum of the thicknesses of the intermediate layer and the shell layer is preferably 10 nm or less. It is more preferable to satisfy both of these at the same time. The lower limit of the particle size of the core layer is not necessarily limited, but a core-shell polymer having a good uniformity in particle size distribution and thickness of each layer can be easily produced industrially with good reproducibility by an emulsion polymerization method. In this respect, the particle size of the core layer is preferably not smaller than 60 nm, and more preferably not smaller than 90 nm. Also, there is not necessarily a limitation on the lower limit of the sum of the thicknesses of the intermediate layer and the shell layer, but in the same point as described above, the sum of the thicknesses is preferably not less than 2.0 nm.

The particle size of the core layer is determined, for example, by measuring only the average diameter of the core layer based on observation of the core-shell polymer by an electron microscope, or by measuring only the core layer portion obtained in the core layer polymerization step for producing the core-shell polymer. It can be determined by a method such as a dynamic light scattering method for particles obtained. The sum of the thicknesses of the intermediate layer and the shell layer is a half of the difference between the particle diameter of the core-shell polymer and the particle diameter of the core layer.
Can be grasped as the value of. The particle diameter of the core-shell polymer is, for example, measurement of the average diameter of the core-shell polymer based on electron microscope observation of the core-shell polymer,
It can be determined by a method such as dynamic light scattering measurement of the core-shell polymer. The measurement based on the above electron microscope observation is, for example, selectively staining a predetermined layer of a core-shell polymer by an electron staining method, and using a transmission electron microscope (TEM) or a scanning electron microscope (SEM) to measure the core layer or the core shell. The measurement can be performed by actually measuring the diameter of the entire polymer and determining the average value. The dynamic light scattering measurement described above uses the principle that the Brownian motion of particles is slow for large particles and fast for small particles.

Next, the condition (5) will be described.

The condition (5) is such that the polyethylene terephthalate resin (A) and the core-shell polymer (B) constituting the polyethylene terephthalate resin composition are different from the polyethylene terephthalate resin (A) in refractive index and core-shell polymer (B). Where X and Y represent the refractive indices of

[0052]

| X−Y | ≦ 0.020

It means that the condition shown by the following is satisfied.

Polyethylene terephthalate resin (A)
If the absolute value of the difference between the refractive index of the polyethylene terephthalate resin composition and the refractive index of the core-shell polymer (B) is larger than 0.020, the transparency of the polyethylene terephthalate resin composition becomes insufficient. In that the transparency of the polyethylene terephthalate resin composition is particularly good, the absolute value of the difference between the refractive index of the polyethylene terephthalate resin (A) and the refractive index of the core-shell polymer (B) is 0.016 or less. Is preferred. The lower limit of the absolute value of the difference between the refractive index of the polyethylene terephthalate-based resin (A) and the refractive index of the core-shell polymer (B) is not necessarily limited, but it is excellent to try to make the absolute value too small. It becomes difficult to produce the core-shell polymer (B) having an effect of improving the impact resistance by using an easily available monomer, and the transparency required of the polyethylene terephthalate-based resin composition is usually normal. Since it is not necessary to make the absolute value excessively small,
The absolute value need not be set smaller than 0.006.
The refractive index of the polyethylene terephthalate-based resin (A) and the refractive index of the core-shell polymer (B) can each be measured according to a conventional method. For example, the refractive index is measured using a plate-like sample molded from the resin or the core-shell polymer. It can be measured with a rate meter. When the polyethylene terephthalate resin (A) is a mixture of two or more polyethylene terephthalate resins, the refractive index of the polyethylene terephthalate resin (A) is the refractive index of the mixture.

Polyethylene terephthalate resin (A)
Is usually in the range of 1.567 to 1.580, so that the core-shell polymer (B) used is 1.547.
When the refractive index is within the range of 1.574, the above condition (5) is likely to be satisfied. Therefore, although not necessarily limited, the core-shell polymer used for producing the polyethylene terephthalate-based resin composition of the present invention has the above conditions (1) to (4) and the refractive index of 1.547 to 1.5. A core-shell polymer that satisfies the condition of being within the range of .574 is often suitable.

The core-shell polymer (B) used in the present invention can be produced according to a known method for producing a general core-shell polymer. That is, for example, it can be manufactured by sequentially forming a core layer, an intermediate layer, and a shell layer by adding a predetermined monomer to a reaction system stepwise according to a known seed polymerization method. After polymerization, the produced core-shell polymer (B) can be removed from the reaction system by a method such as a freezing method and a salting-out method. When taken out by the freezing method, polyethylene terephthalate resin (A)
In order to obtain a core-shell polymer (B) which is easily dispersed uniformly by melt-kneading with the above, it is preferable to take out the core-shell polymer with an aggregated particle size of 1000 μm or less, and more preferably with an aggregated particle size of 500 μm or less.

In the polyethylene terephthalate-based resin composition of the present invention, the composition ratio of the polyethylene terephthalate-based resin (A) and the core-shell polymer (B) is not necessarily limited, and the performance required for the polyethylene terephthalate-based resin composition is not limited. Can be set appropriately according to the conditions. For example, for the purpose of mainly utilizing the physical properties of the polyethylene terephthalate resin (A) and improving the impact resistance deficient in the polyethylene terephthalate resin (A) with the core-shell polymer (B), the polyethylene terephthalate resin (A) is used. ) And the core-shell polymer (B) are (A) /
It is preferable to use such a ratio that the weight ratio of (B) falls within the range of 70/30 to 99/1.
It is more preferable to use it at a ratio that falls within the range of 0 to 96/4, and even more preferably to use it at a ratio that falls within the range of 85/15 to 95/5.

The polyethylene terephthalate resin composition of the present invention contains other components, if necessary, in addition to the polyethylene terephthalate resin (A) and the core-shell polymer (B) as long as the effects of the present invention are not lost. It may be. Optional components include additives such as antioxidants, viscosity improvers, heat stabilizers, and anti-stick agents.

The polyethylene terephthalate-based resin composition of the present invention can exhibit transparency equivalent to or very close to that of the polyethylene terephthalate-based resin, and for example, can have a total light transmittance of 80% or more. is there.

The polyethylene terephthalate resin composition of the present invention comprises a polyethylene terephthalate resin (A)
And a core-shell polymer (B). As a method of blending the core-shell polymer (B) with the polyethylene terephthalate-based resin (A), it is possible to directly melt-knead at the time of molding such as injection molding, direct blow molding, or extrusion molding.
Before molding, it is possible to melt and knead both using an extruder such as a screw-type single-screw extruder or a screw-type twin-screw extruder in the workability at the time of molding, the resin composition constituting the molded article. It is preferable in view of the uniformity of dispersion of the core-shell polymer. The melt-kneading of the polyethylene terephthalate-based resin (A) and the core-shell polymer (B) may be performed in two or more stages. For example, a part of the polyethylene terephthalate-based resin (A) and the core-shell polymer (B) are subjected to a first melt-kneading step to prepare a preliminary polyethylene terephthalate-based resin composition having a relatively high core-shell polymer concentration. Then, the preliminary polyethylene terephthalate-based resin composition can be subjected to a second melt-kneading step with the rest of the polyethylene terephthalate-based resin to produce the final target polyethylene terephthalate-based resin composition. From the viewpoint that a polyethylene terephthalate-based resin composition in which a relatively low content of the core-shell polymer (B) is uniformly dispersed can be efficiently produced, the polyethylene terephthalate-based resin (A) / core-shell polymer ( A preliminary polyethylene terephthalate-based resin composition having a weight ratio of B) in the range of 40/60 to 70/30 is prepared, and then the remaining polyethylene terephthalate-based resin (A) is melt-kneaded. It is preferable to employ a two-stage melt-kneading method.

Polyethylene terephthalate resin (A)
In the melt-kneading of the core-shell polymer (B) and the core-shell polymer (B), any conditions can be adopted as appropriate, but the core-shell polymer (B) is dispersed as uniformly as possible, and the polyethylene terephthalate resin (A) is thermally degraded and hydrolyzed. It is preferable to adopt a condition which can suppress as much as possible. From the viewpoint of preventing hydrolysis, it is preferable that water is not present in the melt-kneading system as much as possible. Therefore, the polyethylene terephthalate-based resin (A) and / or the preliminary polyethylene terephthalate-based resin composition to be subjected to the condition melt-kneading are prepared in advance. Drying sufficiently (for example, drying at 120 ° C. for 4 hours or more to reduce the water content to 0.2% or less), using an extruder equipped with a vent mechanism as a melt kneading apparatus, and the like. preferable. Further, from the viewpoint of uniform dispersion and prevention of thermal deterioration, 24
At a temperature in the range of 0 to 300 ° C., it is preferable to melt-knead the core-shell polymer (B) with a minimum residence time sufficient to uniformly disperse the core-shell polymer (B).

When the polyethylene terephthalate resin composition of the present invention is produced, a polyethylene terephthalate resin for recycling recovered from a used bottle or the like may be used as at least a part of the polyethylene terephthalate resin (A). . The polyethylene terephthalate-based resin for recycling has a lower thermal weight than the unused polyethylene terephthalate-based resin due to a higher heat history, and is further inferior in impact resistance. In the polyethylene terephthalate resin composition of the present invention, the impact resistance is improved by the addition of the core-shell polymer (B). Therefore, when the polyethylene terephthalate resin for recycling is used as at least a part of the polyethylene terephthalate resin (A). The effect of the present invention is particularly effectively exhibited, and the range of use of the polyethylene terephthalate resin for recycling is expanded.

The polyethylene terephthalate-based resin composition of the present invention can be subjected to various molding methods applicable to ordinary polyethylene terephthalate-based resins, whereby a molded article having an arbitrary shape and dimensions can be produced. Can be. As such a molding method, extrusion molding, injection molding, blow molding, calendar molding, casting, press molding, melt spinning and the like can be adopted.

The polyethylene terephthalate-based resin composition of the present invention can exhibit the same or nearly the same transparency as the contained polyethylene terephthalate-based resin (A), but can provide a molded article having sufficient transparency. In order to obtain such a case, it is preferable to use a polyethylene terephthalate resin having low crystallinity or an amorphous polyethylene terephthalate resin as the polyethylene terephthalate resin (A), and to adopt molding conditions in which crystallization hardly occurs. There is. These conditions are particularly effective when a thick molded article is manufactured by the injection molding method. For example, when a crystalline polyethylene terephthalate resin such as polyethylene terephthalate (PET) is used as the main component of the polyethylene terephthalate resin (A), a small proportion of naphthalenedicarboxylic acid, isophthalic acid, cyclohexanedicarboxylic acid, etc. is copolymerized. Amorphous polyethylene terephthalate-based resin such as polyethylene terephthalate-based copolymer was prepared such that the weight ratio of crystalline polyethylene terephthalate-based resin / amorphous polyethylene terephthalate-based resin was in the range of 50/50 to 90/10. The crystallization speed is reduced, and crystallization hardly occurs during molding. Injection molding conditions for making crystallization difficult include lowering the mold temperature.

Molded articles made of the polyethylene terephthalate resin composition of the present invention include sheets, films, plates, belts, rolls, curl cords, hoses, tubes, vibration damping materials, vibration damping materials, machine parts, automobile parts, and electric parts.・ Electronic components,
It can be used as sporting goods, fiber, etc.
Examples of applications in which the excellent transparency and excellent impact resistance of the molded article made of the polyethylene terephthalate-based resin composition of the present invention are particularly effectively used include general household articles such as combs, containers, buckets, hangers, and the like; Pen shaft, underlay,
Stationery such as a case; industrial supplies such as a component case, a signboard, and a device housing.

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EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

The chemical substances used in the production examples of the core-shell polymer shown below as reference examples are as follows.

Monomers: styrene (St), methyl methacrylate (MMA), methyl acrylate (MA),
Methacrylic acid (MAA), butyl acrylate (B
A), allyl methacrylate (ALMA), divinylbenzene (DVB), 1,6-hexanediol diacrylate (HDDA)

Surfactant: dioctyl sodium sulfosuccinate (SDOSS)

Polymerization initiator: potassium peroxodisulfate (KPS)

Reference Example 1 (Three-layer core-shell polymer (B-
Production of 1)) In a polymerization vessel having a capacity of 10.0 liters equipped with a reflux condenser, 5000 g of ion-exchanged water and 11.50 of SDOSS were added.
g, and the temperature was raised to 80 ° C. while stirring under a nitrogen stream. To this, 1900.0 g of St and 76.0 DVB
g of the monomer mixture was added all at once and emulsified for 30 minutes, and then 1900 mg of KPS was added and stirred for 2 hours to perform seed polymerization for forming a core layer. After the first-stage seed polymerization was performed as described above, 500 mg of KPS was added, and the mixture was stirred for 5 minutes. In addition, BA500.0g and ALMA2.50g SDO
A monomer mixture obtained by dissolving 2.0 g of SS was continuously fed over 60 minutes to perform seed polymerization for forming an intermediate layer. After performing the second-stage seed polymerization as described above, the mixture was aged for 1 hour, then 100 mg of KPS was added, and the mixture was stirred for 5 minutes. To this, 85.0 g of MMA, MA
A monomer mixture obtained by dissolving 0.4 g of SDOSS in 5.0 g and 10.0 g of MAA was continuously fed over 30 minutes to perform seed polymerization for forming a shell layer. After seed polymerization for forming the shell layer, the mixture was aged for 1 hour, cooled to room temperature, and filtered through a plastic net having openings of 150 μm to obtain a three-layer core-shell polymer latex. This latex was frozen at −30 ° C., dehydrated and washed with a suction filter, and then dried at 60 ° C. for 24 hours under a blowing condition to obtain a core-shell polymer (B-1). With respect to the obtained core-shell polymer (B-1), the glass transition temperature of each layer, the particle diameter of the core layer, the sum of the thicknesses of the intermediate layer and the shell layer, and the refractive index were measured by the following methods.

Measurement of Glass Transition Temperature of Each Layer A glass transition temperature measurement sample was prepared by cutting a three-layer core-shell polymer into a 1.2 mm-thick plate by compression molding, and cutting the plate into a width of 5 mm and a length of 30 mm. did. The glass transition temperature of each layer in the three-layer core-shell polymer was determined based on viscoelasticity measurement using the flat sample. That is, using a viscoelasticity measuring device manufactured by Rheology Co., the frequency was fixed and a constant strain amplitude was forcibly applied to the sample, and the stress was measured while changing the temperature. From the measurement results, the temperature dispersion of the dynamic loss (tan δ) of the polymer constituting each layer was determined, and the temperature at which the loss peak occurred was defined as the glass transition temperature.

Measurement of Particle Diameter of Core Layer The particle diameter of the core layer in the core-shell polymer was determined by a dynamic light scattering method. That is, a sample was collected from the latex of particles corresponding to the core layer obtained by polymerization of the core layer (first-stage seed polymerization). After diluting this sample with ion-exchanged water, take out the sample into a measurement cell, and set it in a cell chamber of a dynamic light scattering particle size measurement device manufactured by Otsuka Electronics Co., Ltd. so that the reference scattering intensity value is in the range of 8000 to 12000. The particles were irradiated with laser light with adjustment. The particle size obtained by analyzing the fluctuation of the scattered light using the photon correlation method was recognized as the particle size of the core layer in the core-shell polymer.

Measurement of the sum of the thicknesses of the intermediate layer and the shell layer The sum of the thicknesses of the intermediate layer and the shell layer in the core-shell polymer is determined by the difference between the particle diameter of the core-shell polymer and the particle diameter of the core layer obtained by the above method. The value was calculated as a value of 1/2. The particle size of the core-shell polymer is determined by using the same dynamic light scattering method as described above, using a sample collected from the core-shell polymer latex obtained by polymerization of the shell layer (third stage seed polymerization). It was measured.

Measurement of Refractive Index of Core-Shell Polymer From a three-layer core-shell polymer, 1.2 mm was obtained by compression molding.
A flat sample having a thickness was prepared, and the refractive index of this sample at 23 ° C. was measured using an Abbe refractometer manufactured by Atago Co., Ltd. according to a method in accordance with JIS K7105, and the measured refractive index was defined as the refractive index of the three-layer core-shell polymer. .

The measurement results of the glass transition temperature, the core layer particle diameter, the sum of the thicknesses of the intermediate layer and the shell layer, and the refractive index of the core-shell polymer (B-1) by the above-mentioned methods are as follows.
Table 3 below as a part of the data of Example 1 described later.
Shown in

Reference Examples 2 to 9 (Production of Various Core-Shell Polymers) The core-shell polymer (B) was prepared in the same manner as in Reference Example 1 except that the amounts of the chemical substances shown in Table 1 or Table 2 below were used. -2) to (B-9) were prepared, and the same glass transition temperature, core layer particle diameter, sum of the thicknesses of the intermediate layer and the shell layer, and the refractive index were measured as in Reference Example 1. In Reference Example 9 (manufacturing example of core-shell polymer (B-9)), the intermediate layer forming step was omitted. In addition, the measurement results are shown in Tables 3 and 4 below as a part of data of Examples and Comparative Examples described later.

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[Table 1]

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[Table 2]

Example 1 The three-layer core-shell polymer (B-
100 parts by weight of 1), 100 parts by weight of polyethylene terephthalate containing 0.5% by weight of an antioxidant and 2 parts by weight
A master batch was prepared by supplying the mixture to a shaft extruder and performing melt-kneading at a temperature of 270 ° C. 200 parts by weight of this master batch was mixed with polyethylene terephthalate 80
By supplying to an injection molding machine together with 0 parts by weight, 28
After kneading with a screw set at 0 ° C., the mixture was molded into a flat molded product having a predetermined thickness. Using the obtained flat molded product, an impact resistance test, a falling ball impact test, and a transparency test were performed by the following methods.

Impact Resistance Test A notch was formed on the obtained molded product with a cutting tool,
An Izod impact test specimen having a thickness of 3.0 mm specified in K7110 was produced. Using this test piece, an impact value at a temperature of 23 ° C. and a humidity of 47% was measured by a method in accordance with JIS K7110. Ten measurements were made, and the average value was used.

Falling ball impact test The obtained molded product (100.0 mm on a side, 1.0 mm in thickness)
Is placed on the center of a metal supporting frame having a square concave portion with a side of 90.0 mm at the center, and a metal ball weighing 1.0 kg is placed at a predetermined height (60 cm, 80 cm).
m, 100 cm, 120 cm, and 140 cm) to the center of the flat plate, and the number of breaks of the flat plate was measured. The number of tests from the predetermined height was 5 each, and the height one step lower than the minimum height at which half or more of them broke (20 cm lower height) was determined as the falling ball impact height.

Transparency Test The obtained molded product (a flat plate having a thickness of 1.0 mm) was measured for the total light transmittance by a method in accordance with JIS K6714. Two measurements were made and the average was used.

The results of the various measurements are shown in Table 3 below.

A 1.2 mm-thick plate-shaped sample produced by compression-molding the same polyethylene terephthalate as that used in Example 1 was used in accordance with JIS K7105 using an Abbe refractometer manufactured by Atago. As a result of measuring the refractive index at 23 ° C. by the above method, the refractive index was 1.575.

Examples 2 to 5 and Comparative Examples 1 to 4 Except that one of the core-shell polymers (B-2) to (B-9) shown in Table 3 or Table 4 below is used as the core-shell polymer. In the same manner as in Example 1, flat molded articles each having a predetermined thickness made of the polyethylene terephthalate resin composition were prepared, and subjected to an impact resistance test, a falling ball impact test, and a transparency test. The obtained measurement results are shown in Tables 3 and 4 below.

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[Table 3]

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[Table 4]

Comparative Example 5 The same polyethylene terephthalate as that used in Example 1 was subjected to the same injection molding as in Example 1 to produce a flat molded article of polyethylene terephthalate having a predetermined thickness. Using the obtained molded product, an impact resistance test, a falling ball impact test and a transparency test were performed in the same manner as in Example 1. The impact strength was 2.9 kJ / m ² , the falling ball impact value was less than 60 cm, and the total light transmittance was 90.5%.

From the results in Table 3 and Comparative Example 5, the polyethylene terephthalate resin compositions according to the present invention obtained in Examples 1 to 5 were almost as high as those of Comparative Example 5 using polyethylene terephthalate alone. Excellent transparency as shown by the light transmittance data, and at the same time, shock resistance as shown by the data of significantly higher impact strength and significantly higher falling ball impact height than polyethylene terephthalate alone It turns out that it is also excellent. And among these, the particle size of the core layer is 150
nm or less, and the sum of the thicknesses of the intermediate layer and the shell layer is 10
nm or less, and the polyethylene terephthalate-based resin composition (Examples 1 and 2) using a core-shell polymer having an absolute value of a difference in refractive index from the polyethylene terephthalate-based resin of 0.016 or less has particularly high transparency. It turns out that it becomes favorable.

On the other hand, from Table 4 above, Comparative Examples 1 to 4
It can be seen that the polyethylene terephthalate-based resin composition other than the present invention obtained in the above cannot achieve both excellent transparency and excellent impact resistance. That is, the particle diameter of the core layer in the used core-shell polymer is 170
In the polyethylene terephthalate-based resin compositions (Comparative Examples 1 and 3) which are different from the present invention in that the absolute value of the difference in refractive index from the polyethylene terephthalate-based resin is larger than 0.020 or larger than 0.020 nm, the transparency is low. It turns out that it is low. It can be seen that the polyethylene terephthalate-based resin composition (Comparative Example 2), which is different from the present invention in that the content of the intermediate layer in the used core-shell polymer is less than 10% by weight, has low impact resistance. Also, it can be seen that the polyethylene terephthalate-based resin composition (Comparative Example 4), which is different from the present invention in that the core-shell polymer used has two layers, has low impact resistance.

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Industrial Applicability The polyethylene terephthalate resin composition of the present invention has a highly improved impact resistance as compared with a polyethylene terephthalate resin while maintaining the excellent transparency of the polyethylene terephthalate resin at a high level. Can be demonstrated. In addition, the core-shell polymer used in the polyethylene terephthalate resin composition of the present invention does not need to include a chemical structure derived from a conjugated diene compound such as butadiene, and thus can exhibit good weather resistance.

Claims (4)

[Claims] 1. A polyethylene terephthalate-based resin (A) and the following conditions (1) to (5): (1) a core layer composed of a monomer polymer mainly composed of a styrene-based compound; It has a three-layer structure composed of an intermediate layer composed of a monomer polymer mainly composed of an alkyl acrylate of 2 to 8 and a shell layer composed of a monomer polymer mainly composed of methyl methacrylate; (2) The content of the intermediate layer is 10% by weight or more based on the whole of the core layer, the intermediate layer, and the shell layer; (3) The particle size of the core layer is 170 nm or less. (4) the sum of the thicknesses of the intermediate layer and the shell layer is 15 nm;
(5) an absolute value of a difference in refractive index between the polyethylene terephthalate resin (A) and the polyethylene terephthalate resin (A) is 0.020 or less; Polyethylene terephthalate resin composition. 2. A polyethylene terephthalate-based resin (A) is used under the following conditions (1) to (5): (1) a core layer composed of a monomer polymer mainly composed of a styrene-based compound, and a carbon number of an alkyl group. Having a three-layer structure composed of an intermediate layer composed of a polymer of a monomer mainly composed of alkyl acrylate whose is 2 to 8, and a shell layer composed of a polymer of a monomer mainly composed of methyl methacrylate (2) the content of the intermediate layer is 10% by weight or more based on the whole of the core layer, the intermediate layer, and the shell layer; and (3) the particle size of the core layer is 170 nm or less. (4) The sum of the thicknesses of the intermediate layer and the shell layer is 15 nm.
(5) a core-shell polymer (B) that satisfies all of the following conditions: (5) the absolute value of the difference in the refractive index from the polyethylene terephthalate-based resin (A) is 0.020 or less;
And a method for producing a polyethylene terephthalate-based resin composition, which is mixed under melting conditions. 3. A molded article comprising the polyethylene terephthalate resin composition according to claim 1. 4. A core layer composed of a polymer of a monomer mainly composed of a styrene compound, wherein the alkyl group has 2 carbon atoms.
Having a three-layer structure composed of an intermediate layer composed of a polymer of a monomer mainly composed of alkyl acrylate and a shell layer composed of a polymer of a monomer mainly composed of methyl methacrylate; 2) the content of the intermediate layer is 10% by weight or more based on the entire core-shell polymer; (3) the particle size of the core layer is 170 nm or less; (4) the thickness of the intermediate layer and the shell layer. Sum is 15nm
And (5) a refractive index in the range of 1.547 to 1.574; and a core-shell polymer.