JP7342033B2 - Multilayer structure polymer particles, thermoplastic resin compositions containing the same, molded bodies and films - Google Patents

Description

The present invention relates to multilayer structure polymer particles, thermoplastic resin compositions, molded articles, and films containing the same.

(Meth)acrylic resin is a resin used in various fields because it has excellent transparency, color tone, appearance, weather resistance, gloss, and processability. In particular, films molded from (meth)acrylic resins have high transparency, low moisture permeability, and are easy to perform primary processing and secondary processing, so they are widely used in optical applications, decorative applications, and the like.
Generally, acrylic resins are brittle and lack impact resistance, but by blending a graft copolymer with a crosslinked rubber layer into an acrylic resin, etc., the particle size of the graft copolymer with a crosslinked rubber layer can be controlled. This results in impact resistance and strength (Patent Document 1). Furthermore, molded products such as films using resin compositions in which a graft copolymer having a rubber layer is blended with an acrylic resin have been proposed (Patent Documents 2 and 3).
However, the above-mentioned molded product has a problem in that when the molding temperature becomes high, the number of defects caused by the deterioration of the resin increases. As a method to reduce these defects, organic fine particles have been proposed in which a particulate polymer having an average particle diameter of 0.01 μm to 1 μm as a core portion is further polymerized with (meth)acrylic acid ester as a shell portion. (Patent Document 4).

Japanese Unexamined Patent Publication No. 48-55233 International Publication No. 2016/139927 International Publication No. 2017/204243 Japanese Patent Application Publication No. 2007-254727

However, the methods disclosed in Patent Documents 1 to 4 may not be able to sufficiently reduce the spot defects of molded bodies containing films, and there is room for improvement in the multilayer structure polymer particles used.
In view of the above-mentioned circumstances, the present invention aims to reduce the defects in molded products including films by providing a multilayer structure that has excellent long-term thermal stability in a matrix resin (base resin), as well as excellent dispersibility and impact resistance. The purpose is to provide coalesced particles.

As a result of intensive studies on the above-mentioned problems, the present inventors found that the mass ratio of each layer of multilayer polymer particles and the glass transition temperature of the outer layer are important in order to improve long-term thermal stability, dispersibility, and impact resistance. As a result of further investigation based on this finding, the present invention was achieved.
That is, the present invention includes the following [1] to [14].
[1] Multilayer structure polymer particles having an inner layer containing a crosslinked rubber (I) and an outer layer containing a thermoplastic resin (II) graft-bonded to the inner layer,
The ratio [V2/V1] of the mass (V2) of the outer layer to the mass (V1) of the inner layer is 0.3 to 0.8,
Multilayer structure polymer particles, wherein the outer layer has a glass transition temperature of 80 to 120°C.
[2] Regarding the thermoplastic resin (II) graft-bonded with the inner layer, the grafting ratio expressed as the ratio of the mass of the thermoplastic resin (II) to the mass of the inner layer is 25 to 90% by mass. The multilayer structure polymer particles described in [1].
[3] The multilayer structure polymer particles according to [1] or [2], which have a median diameter of 80 to 500 nm as measured by laser diffraction/scattering method.
[4] The multilayer structure structure according to any one of [1] to [3], wherein the thermoplastic resin (II) graft-bonded to the inner layer has a number average molecular weight of 20,000 to 50,000. coalescent particles.
[5] The crosslinked rubber (I) contains 50 to 99.99% by mass of acrylic acid ester units, 0.01 to 5% by mass of polyfunctional monomer units, and unsaturated monomers copolymerizable with these. The thermoplastic resin (II) containing 0 to 49.99% by mass of methacrylic acid ester units and graft-bonded to the inner layer contains 40 to 100% by mass of methacrylic acid ester units and other unsaturated monomers copolymerizable therewith. The multilayer structure polymer particles according to any one of [1] to [4], containing 0 to 60% by mass of mer units.
[6] Thermoplastic resin composition containing 5 to 95% by mass of thermoplastic resin (III) and 5 to 95% by mass of the multilayer structure polymer particles according to any one of [1] to [5]. .
[7] The thermoplastic resin composition according to [6], wherein the thermoplastic resin (III) is an amorphous resin.
[8] The thermoplastic resin composition according to [6] or [7], wherein the thermoplastic resin (III) has a glass transition temperature of 50 to 170°C.
[9] The thermoplastic resin composition according to any one of [6] to [8], wherein the thermoplastic resin (III) has a number average molecular weight of 10,000 to 500,000.
[10] The thermoplastic resin composition according to any one of [6] to [9], wherein the thermoplastic resin (III) is a (meth)acrylic resin.
[11] The thermoplastic resin (III) is a (meth)acrylic resin containing 80 to 99.9% by mass of methacrylic ester units and 0.1 to 20% by mass of acrylic ester units, [6] The thermoplastic resin composition according to any one of [10].
[12] A molded article comprising the thermoplastic resin composition according to any one of [6] to [11].
[13] A film comprising the thermoplastic resin composition according to any one of [6] to [11].
[14] A molded article comprising the multilayer structure polymer particles according to any one of [1] to [5].

According to the present invention, it is possible to provide multilayer structure polymer particles that have excellent long-term thermal stability in a matrix resin (base resin), as well as excellent dispersibility and impact resistance.

A multilayer structure polymer particle according to an embodiment of the present invention, wherein the inner layer consists of one layer (first layer) and the outer layer consists of two layers (second layer, third layer). FIG. 3 is a diagram showing particles. A multilayer structure polymer particle according to an embodiment of the present invention, wherein the inner layer consists of two layers (first layer, second layer) and the outer layer consists of one layer (third layer). FIG. 3 is a diagram showing particles. A multilayer structure polymer particle according to an embodiment of the present invention, wherein the inner layer consists of two layers (first layer, second layer) and the outer layer consists of two layers (third layer, fourth layer). FIG. 3 is a diagram showing a multilayer structure polymer particle. A multilayer structure polymer particle according to an embodiment of the present invention, wherein the inner layer consists of two layers (first layer, second layer) and the outer layer consists of two layers (third layer, fourth layer). FIG. 3 is a diagram showing a multilayer structure polymer particle.

The multilayer structure polymer particles of the present invention are multilayer structure polymer particles having an inner layer containing a crosslinked rubber (I) and an outer layer containing a thermoplastic resin (II) graft-bonded to the inner layer, wherein the inner layer The ratio [V2/V1] of the mass (V2) of the outer layer to the mass (V1) of the outer layer is 0.3 to 0.8. [V2/V1] can be adjusted by adjusting the amount of the monomer mixture used for polymerizing the inner and outer layers of the multilayer structure polymer particles of the present invention. [V2/V1] of the multilayer structure polymer particles of the present invention is preferably 0.35 to 0.78, more preferably 0.4 to 0.75. By being within this range, the long-term thermal stability and impact resistance of the multilayer structure polymer particles and the dispersibility of the multilayer structure polymer particles in the matrix are improved. When [V2/V1] is less than 0.3, long-term thermal stability in the matrix resin may deteriorate. Moreover, when [V2/V1] is more than 0.8, impact resistance may be reduced. From the viewpoint of degradability of the crosslinked rubber in the matrix resin and thermal stability in the retention area during film formation of multilayer structure polymer particles, [V2/V1] is preferably 0.5 or more. , more preferably 0.55 or more, still more preferably 0.60 or more, even more preferably 0.65 or more, and particularly preferably 0.70 or more.

Further, in the present invention, the glass transition temperature (Tg) of the outer layer is 80 to 120°C. When the glass transition temperature (Tg) of the outer layer is within this range, the particles of the multilayer structure polymer can be easily isolated (hereinafter also referred to as "good retrieval properties"), and the multilayer structure in the matrix can be easily isolated. The dispersibility of polymer particles is improved. If the glass transition temperature of the outer layer is less than 80° C., blocking is likely to occur during the powder drying process, and it may become difficult to isolate the multilayer structure polymer particles. Furthermore, the dispersibility during melt-kneading may be reduced, and defects such as fish eyes may be more likely to occur. Furthermore, if the glass transition temperature is higher than 120° C., it may be difficult to form aggregates when the powder is taken out by the freeze-solidification method, and it may be difficult to isolate the powder as a powder. From these viewpoints, the glass transition temperature of the outer layer is preferably 83°C to 110°C, more preferably 85°C to 105°C.
In addition, when the outer layer of the multilayer structure polymer particles of the present invention exhibits a glass transition temperature of 2 or more, the highest glass transition temperature is the glass transition temperature of the outer layer, and the glass transition temperature in the present invention is determined by the glass transition temperature described in the Examples. Refers to the value measured by the measurement method.

In the multilayer structure polymer particles of the present invention, when there is only one crosslinked rubber layer, the crosslinked rubber layer alone or the crosslinked rubber layer and the inner layer together are referred to as the "inner layer", and the crosslinked rubber layer is referred to as the "inner layer". The layer outside the rubber layer is called the "outer layer." On the other hand, when there are two or more crosslinked rubber layers, the outermost crosslinked rubber layer and the layers inside the crosslinked rubber layer are collectively referred to as the "inner layer," and the layers outside the crosslinked rubber layer are referred to as the "inner layer." called the outer layer. Specific examples of the multilayer structure polymer particles of the present invention are illustrated in FIGS. 1 to 4.
FIG. 1 shows a multilayer structure polymer particle having one crosslinked rubber layer, in which the crosslinked rubber layer alone forms an inner layer, and a crosslinked PMMA (polymethyl methacrylate) layer and PMMA outside the crosslinked rubber layer. FIG. 2 is a diagram showing a multilayer structure polymer particle in which the layers constitute the outer layer. Moreover, FIG. 2 is a diagram showing a multilayer structure polymer particle in which a crosslinked rubber layer and a crosslinked PMMA layer inside the crosslinked rubber layer form an inner layer, and a PMMA layer outside the crosslinked rubber layer forms an outer layer.
Further, FIG. 3 is a diagram showing a multilayer structure polymer particle in which a crosslinked rubber layer and a crosslinked PMMA layer inside the crosslinked rubber layer form an inner layer, and two PMMA layers outside the crosslinked rubber layer form an outer layer, FIG. 4 is a diagram showing a multilayer structure polymer particle in which a crosslinked rubber layer and a crosslinked PMMA layer inside the crosslinked rubber layer form an inner layer, and a crosslinked PMMA layer and a PMMA layer outside the crosslinked rubber layer form an outer layer. be.

The crosslinked rubber (I) is not particularly limited, and includes butadiene rubber, styrene-butadiene rubber, isoprene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, butyl rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, urethane rubber, and silicone rubber. , fluororubber, chlorosulfonated polyethylene rubber, acrylic rubber, etc., and acrylic rubber is particularly preferably used.

The acrylic rubber used for the crosslinked rubber (I) consists of structural units derived from acrylic esters (hereinafter sometimes referred to as acrylic ester units) and structural units derived from polyfunctional monomers (polyfunctional monomers). mer unit).

Examples of acrylic esters used in the crosslinked rubber (I) include methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, i-propyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, Examples include octyl acrylate, lauryl acrylate, hydroxyhexyl acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, cyclohexyl acrylate, benzyl acrylate, etc., with 2-ethylhexyl acrylate and n-butyl acrylate being preferred, and n-butyl acrylate being preferred. More preferred. These may be used alone or in combination of two or more.

The content of acrylic ester units in the crosslinked rubber (I) is preferably 50 to 99.99% by mass, more preferably 60 to 99% by mass, and even more preferably 70 to 98% by mass. . By being within this range, good impact resistance can be provided.

Examples of the polyfunctional monomer used in the crosslinked rubber (I) include ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, divinylbenzene, and allyl methacrylate. , allyl acrylate, allyl maleate, allyl fumarate, diallyl fumarate, triallyl cyanurate, etc., with allyl acrylate and allyl methacrylate being preferred, and allyl methacrylate being more preferred. These may be used alone or in combination of two or more.

The content of polyfunctional monomer units in the crosslinked rubber (I) is preferably 0.01 to 5% by mass, more preferably 0.1 to 4.5% by mass, and 1 to 4% by mass. % is more preferable. By staying within this range, a desired grafting rate can be achieved.

The crosslinked rubber (I) may further contain other unsaturated monomers copolymerizable with the acrylic ester or polyfunctional monomer, such as 1,3-butadiene, 1,2-butadiene, Isoprene, styrene, α-methylstyrene, vinyltoluene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, n- Examples include octyl methacrylate, lauryl methacrylate, hydroxyhexyl methacrylate, isobornyl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, acrylonitrile, and methacrylonitrile. These may be used alone or in combination of two or more.

The content of the other unsaturated monomer units in the crosslinked rubber (I) is preferably 0 to 49.99% by mass, more preferably 0.99 to 39.99% by mass, More preferably, it is 1.99 to 29.99% by mass.

The inner layer in the multilayer structure polymer particles of the present invention may be a single layer containing crosslinked rubber (I), or may be two or more layers each containing crosslinked rubber (I) having different compositions. , may contain one or more layers having a different composition from the crosslinked rubber (I), but from the viewpoint of improving the strength of the multilayer structure polymer particles, the innermost layer containing a crosslinked hard body (for example, FIGS. 2, 3, and crosslinked PMMA layer shown in 4). It is particularly preferable that the multilayer structure polymer particles of the present invention have a three-layer structure of a crosslinked hard body, a crosslinked rubber (I), and a thermoplastic resin (II).

It is preferable that the crosslinked hard body includes a structural unit derived from a methacrylic ester (hereinafter also referred to as a "methacrylic ester unit"). Specifically, as the methacrylic ester, a methacrylic ester in which the ester moiety is an alkyl group having 1 to 4 carbon atoms is preferred, and methyl methacrylate is particularly preferred.

The content of methacrylic acid ester units in the crosslinked hard body is preferably 40.0 to 99.0% by mass, more preferably 50.0 to 98.0% by mass, and 60.0 to 97% by mass. It is more preferably .0% by mass, and particularly preferably 80 to 97.0% by mass. When the content of methacrylic acid ester units is within this range, the strength of the multilayer structure polymer particles can be improved.

Moreover, it is preferable that the crosslinked hard body contains a structural unit derived from an acrylic ester. Examples of acrylic esters include esters in which the ester moiety is a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Specifically, the same acrylic esters mentioned as the acrylic ester used in the crosslinked rubber (I) can be used, and the ester moiety is a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent. Acrylic esters are preferred, methyl acrylate, 2-ethylhexyl acrylate, and n-butyl acrylate are more preferred, and methyl acrylate is even more preferred. These may be used alone or in combination of two or more.

The content of acrylic ester units in the crosslinked hard body is preferably 0.1 to 20.0% by mass, more preferably 1.0 to 15.0% by mass, and 3.0 to 10.0% by mass. More preferably, it is 0% by mass. When the content of acrylic ester units is within this range, the impact resistance of the multilayer structure polymer particles can be improved.

Moreover, it is preferable that the crosslinked hard body contains a structural unit derived from a polyfunctional monomer. As the polyfunctional monomer used for the crosslinked hard body, the same ones as those listed as the polyfunctional monomer used for the crosslinked rubber (I) can be used, and allyl acrylate and allyl methacrylate are preferable. Allyl methacrylate is more preferred. These may be used alone or in combination of two or more.

The content of polyfunctional monomer units in the crosslinked hard body is preferably 0.01 to 3.0% by mass, more preferably 0.1 to 2.0% by mass. When the content of the polyfunctional monomer unit is within this range, the desired hardness can be easily adjusted.

The thermoplastic resin (II) grafted to the internal crosslinked material (inner layer) used in the multilayer structure polymer particles of the present invention is not particularly limited, and includes polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyacetic acid. Examples include vinyl, polyurethane, polytetrafluoroethylene, polyamide, polycarbonate, polyester, polyethylene terephthalate, polybutylene terephthalate, polyacetal, and (meth)acrylic resin, with (meth)acrylic resin being particularly preferably used.

The (meth)acrylic resin used as the thermoplastic resin (II) graft-bonded to the inner layer preferably contains a structural unit derived from a methacrylic ester (methacrylic ester unit).
The methacrylic ester used in the thermoplastic resin (II) graft-bonded to the inner layer is preferably a methacrylic ester whose alkyl group has 1 to 4 carbon atoms, and methyl methacrylate is particularly preferred. The methacrylic acid esters used in the thermoplastic resin (II) may be used alone or in combination of two or more.

The content of methacrylic acid ester units in the thermoplastic resin (II) graft-bonded with the inner layer is preferably 40 to 100% by mass, more preferably 50 to 99% by mass, and 60 to 98% by mass. % is more preferable. By being within this range, the strength of the multilayer structure polymer particles can be maintained appropriately.

The thermoplastic resin (II) graft-bonded with the inner layer may further contain a structural unit derived from another unsaturated monomer copolymerizable with the monomer, specifically, methyl Acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, i-propyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, lauryl acrylate, hydroxyhexyl acrylate, isobornyl Structural units derived from acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, cyclohexyl acrylate, benzyl acrylate can be included, but structural units derived from methyl acrylate are preferred.
The other unsaturated monomers used in the thermoplastic resin (II) may be used alone or in combination of two or more.

The content of the unsaturated monomer unit in the thermoplastic resin (II) graft-bonded with the inner layer is preferably 0 to 60% by mass, more preferably 1 to 50% by mass, and 2. More preferably, the amount is 40% by mass.

Although the method for producing the multilayered polymer particles of the present invention is not particularly limited, it is preferable to produce them by an emulsion polymerization method from the viewpoint of ease of particle diameter control. Specifically, examples include crosslinked hard bodies, crosslinked rubber ( In the case of a three-layer structure polymer particle laminated in the order of I) and thermoplastic resin (II), a polymerization reaction step (S1) to form a crosslinked hard body, and a layer containing crosslinked rubber (I) is formed. The polymerization reaction step (S2) for forming a layer containing the thermoplastic resin (II) and the polymerization reaction step (S3) for forming a layer containing the thermoplastic resin (II) can be performed in this lamination order. Hereinafter, an example will be explained in which the three-layered multilayer structure polymer particles are produced by an emulsion polymerization method.

[Polymerization reaction step (S1)]
In the polymerization reaction step (S1), a monomer mixture corresponding to the composition of the crosslinked hard body can be copolymerized by a known method, and specifically, an emulsifier, a pH adjuster, a polymerization initiator, a monomer By mixing the mixture, chain transfer agent, etc. with water and heating it, a polymerization reaction can be carried out to obtain an emulsion of a crosslinked hard body.

[Polymerization reaction step (S2)]
After performing the polymerization reaction step (S1), a monomer mixture, a polymerization initiator, a chain transfer agent, etc. corresponding to the composition of the crosslinked rubber (I) are further added to the emulsion to form the inner first layer. A crosslinked hard body and a layer containing crosslinked rubber (I) as the second layer can be obtained. Note that (S1) and (S2) may each be performed multiple times.

[Polymerization reaction step (S3)]
After performing the polymerization reaction step (S2), a monomer mixture, a polymerization initiator, and a chain transfer agent corresponding to the composition of the thermoplastic resin (II) are added to the emulsion and (co)polymerized. Multilayer structured polymer particles can be obtained.

The emulsifier used in the polymerization reaction steps (S1) to (S3) is not particularly limited as long as it is an emulsifier used in emulsion polymerization, but anionic emulsifiers, nonionic emulsifiers, nonionic/anionic emulsifiers, etc. can be used. can. One or more types of these emulsifiers can be used.
Examples of anionic emulsifiers include dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate and sodium dilauryl sulfosuccinate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; and alkyl sulfates such as sodium dodecyl sulfate. .
Examples of nonionic emulsifiers include polyoxyethylene alkyl ether and polyoxyethylene nonylphenyl ether.
Nonionic/anionic emulsifiers include polyoxyethylene nonylphenyl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate; polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene alkyl ether sulfate; polyoxyethylene tridecyl ether Examples include alkyl ether carboxylates such as sodium acetate.

The polymerization initiator used in the polymerization reaction steps (S1) to (S3) is not particularly limited as long as it generates reactive radicals, such as tert-hexylperoxyisopropyl monocarbonate, tert-hexylperoxy 2 -Ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, tert-butylperoxypivalate, tert-hexylperoxypivalate, tert-butylperoxyneodecanoate -t, tert-hexyl peroxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1,1-bis(tert-hexylperoxy)cyclohexane, benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, lauroyl peroxide, 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2 '-azobis(2-methylpropionate), potassium persulfate, and the like. Among these, potassium persulfate is preferred.

The amount of the polymerization initiator is preferably 0.001 to 0.5 parts by mass, and 0.01 parts by mass, based on 100 parts by mass of each monomer mixture in the polymerization reaction steps (S1) to (S3). It is more preferably 0.4 parts by mass, and even more preferably 0.05 to 0.3 parts by mass.

Examples of the chain transfer agent used in the polymerization reaction steps (S1) to (S3) include n-octylmercaptan, n-dodecylmercaptan, tert-dodecylmercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, and ethylene. Glycol bisthiopropionate, butanediol bisthioglycolate, butanediol bisthiopropionate, hexanediol bisthioglycolate, hexanediol bisthiopropionate, trimethylolpropane tris-(β-thiopropionate) , pentaerythritol tetrakisthiopropionate, and the like. Among these, n-octylmercaptan and n-dodecylmercaptan are preferred, and n-octylmercaptan is more preferred. These may be used alone or in combination of two or more.

The multilayer structure polymer particles can be removed from the emulsion containing the multilayer structure polymer particles obtained by the emulsion polymerization method and purified by a known method, for example, by freeze solidification or washing with water. As a result, the multilayer structure polymer particles of the present invention can be obtained.

The multilayer structure polymer particles of the present invention have [V2/V1] of 0.3 to 0.8, where the mass of the inner layer of the multilayer structure polymer particle is V1 and the mass of the outer layer is V2. , the grafting rate is preferably 25 to 90% by mass, and for this purpose, the amount of chain transfer agent used in the polymerization reaction step (S3) is preferably 100 parts by mass of the monomer mixture used in the step. 0.01 to 0.2 parts by mass, more preferably 0.02 to 0.0.18 parts by mass, even more preferably 0.03 to 0.17 parts by mass, particularly preferably 0.05 parts by mass. ~0.15 part by mass.
Further, the amount of the chain transfer agent used is preferably 1 to 199 parts by mass, more preferably 5 to 190 parts by mass, even more preferably is 10 to 150 parts by mass.

The grafting rate of the multilayer structure polymer particles of the present invention is determined with respect to the inner layer (for example, crosslinked rubber (I) and crosslinked resin) of the multilayer structure polymer particles and the thermoplastic resin (II) grafted to the inner layer. is the ratio of the mass of the thermoplastic resin (II) graft-bonded to the inner layer to the mass of . The grafting rate (mass %) can be determined by the method described in Examples.

The grafting ratio of the multilayer structure polymer particles of the present invention is preferably 25 to 90% by mass, more preferably 28 to 80% by mass, even more preferably 30 to 70% by mass, even more preferably 40% by mass. ~60% by mass. When the graft ratio is within this range, long-term thermal stability and impact resistance in the matrix resin (base resin) are improved.
The grafting rate can be adjusted by adjusting the amount of the polyfunctional monomer, the amount of the chain transfer agent, etc.

The median diameter De of the multilayer structure polymer particles of the present invention measured in an emulsion by laser diffraction/scattering method is preferably 80 to 500 nm, more preferably 150 to 400 nm, and preferably 200 to 300 nm. More preferred. When the median diameter De of the multilayer structure polymer particles is within the above range, the necessary impact resistance can be obtained. Here, the median diameter De is the average value of the outer diameter of the multilayer particle structure of the multilayer structure polymer particle, and can be specifically determined by the method described in the Examples.

The number average molecular weight of the thermoplastic resin (II) graft-bonded to the inner layer is preferably 20,000 to 50,000, more preferably 21,000 to 45,000, and more preferably 22,000. More preferably, it is between 40,000 and 40,000. When the number average molecular weight of the thermoplastic resin (II) graft-bonded to the inner layer is within the above range, multilayer structured polymer particles having excellent long-term thermal stability can be obtained.

It is difficult to directly measure the number average molecular weight of the thermoplastic resin (II) graft-bonded to the inner layer from the multilayer structured polymer particles. The number average molecular weight can be estimated from the number average molecular weight of the non-grafted thermoplastic resin (II). The number average molecular weight of the non-grafted thermoplastic resin (II) can be determined by gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene, and specifically determined by the method described in the Examples. be able to.

The multilayer structure polymer particles of the present invention are multilayer structure polymer particles having an inner layer containing a crosslinked rubber (I) and an outer layer containing a thermoplastic resin (II) graft-bonded to the inner layer. The graft-bonded thermoplastic resin (II) is preferably bonded to the crosslinked rubber (I) in the inner layer of the multilayer structure polymer particles of the present invention.

The present invention includes a thermoplastic resin composition containing the multilayer structure polymer particles and a thermoplastic resin (III) that can serve as a matrix resin (base resin).
As the thermoplastic resin (III), the same ones mentioned as the thermoplastic resin (II) can be used, but an amorphous resin is preferable. Examples of amorphous resins used as the thermoplastic resin (III) include polyvinyl chloride, polystyrene, acrylonitrile/butadiene/styrene, polycarbonate, (meth)acrylic resins, thermoplastic elastomers, etc., especially (meth)acrylic resins. Resins are preferably used.

The thermoplastic resin (III) is preferably a (meth)acrylic resin containing 80 to 99.9% by mass of methacrylic ester units and 0.1 to 20% by mass of acrylic ester units; More preferably, it is a (meth)acrylic resin containing 85 to 99.8% by mass of ester units and 0.2 to 15% by mass of acrylic ester units, and 90 to 99.7% by mass of methacrylic ester units. More preferably, it is a (meth)acrylic resin containing 0.3 to 10% by mass of acrylic acid ester units.

The multilayer structure polymer particles of the present invention may be mixed into the thermoplastic resin (III) in the thermoplastic resin composition. Further, from the viewpoint of transportation, etc., the thermoplastic resin composition of the present invention may be formed into, for example, a pellet shape.

The thermoplastic resin composition of the present invention preferably contains 5 to 95% by mass of multilayer structure polymer particles, more preferably 7 to 80% by mass, and even more preferably 10 to 60% by mass. , it is particularly preferable to contain 15 to 50% by mass. Further, the thermoplastic resin composition of the present invention preferably contains thermoplastic resin (III) in an amount of 5 to 95% by mass, more preferably 20 to 93% by mass, and preferably 40 to 90% by mass. is more preferable, and it is particularly preferable that the content is 50 to 85% by mass.

The glass transition temperature (Tg) of the thermoplastic resin (III) is preferably 50 to 170°C, more preferably 70 to 150°C, and even more preferably 90 to 140°C. When the glass transition temperature (Tg) of the thermoplastic resin (III) is within the above range, stable film formation can be achieved.
Note that the glass transition temperature of the thermoplastic resin (III) refers to a value measured by the measuring method described in Examples.

The number average molecular weight of the thermoplastic resin (III) is preferably 10,000 to 500,000, more preferably 20,000 to 450,000, and preferably 25,000 to 400,000. More preferably, it is from 25,000 to 100,000. When the number average molecular weight of the thermoplastic resin (III) is within the above range, the thermoplastic resin composition of the present invention can exhibit appropriate strength when formed into a molded article such as a film.

The thermoplastic resin composition of the present invention may contain ultraviolet absorbers, antioxidants, colorants, fluorescent color formers, dispersants, heat stabilizers, light stabilizers, etc. as necessary and within the range that does not impair the effects of the present invention. It may contain additives such as stabilizers, infrared absorbers, antistatic agents, processing aids, lubricants, and mold release agents. The coloring agent may be either a pigment or a dye. It may also contain a solvent.
The total content of additives in the thermoplastic resin composition of the present invention is preferably 15 parts by mass or less when the total of the thermoplastic resin (III) and the multilayer structure polymer is 100 parts by mass. , more preferably 10 parts by mass or less. The content of the ultraviolet absorber is preferably 0.1 to 4.0 parts by mass, and 0.2 parts by mass when the total of the thermoplastic resin (III) and the multilayer polymer is 100 parts by mass. It is more preferably at least 1 part by mass, and even more preferably at least 0.4 part by mass. Further, from the viewpoint of reducing costs, the content of the ultraviolet absorber is more preferably 3.8 parts by mass or less, and even more preferably 3.5 parts by mass or less. Further, the content of the antioxidant is preferably 0.005 to 10 parts by mass, and preferably 0.008 to 10 parts by mass when the total of the thermoplastic resin (III) and the multilayer structure polymer is 100 parts by mass. It is more preferably 1 part by mass, and even more preferably 0.01 to 0.2 parts by mass.

The present invention includes a molded article containing the multilayer structure polymer particles of the present invention, a molded article and a film made of the thermoplastic resin composition of the present invention. The film of the present invention is suitably used for optical members such as polarizer protective films, retardation films, retardation plates, light diffusion plates, light guide plates, and the like.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
In Examples and Comparative Examples, physical property values were measured by the following methods. Furthermore, the abbreviations of monomers used in Examples and Comparative Examples are as follows.

MMA: Methyl methacrylate ALMA: Allyl methacrylate MA: Methyl acrylate BA: n-butyl acrylate St: Styrene BzA: Benzyl acrylate n-OM: n-octyl mercaptan

[Number average molecular weight]
It was determined as a polystyrene equivalent molecular weight based on the value measured using GPC (gel permeation chromatography). The measurement conditions were as follows.
Equipment: Tosoh Corporation GPC equipment “HCL-8320”
Separation column: “TTSKguradcolumn SuperHZ-H”, “TSKgel HZM-M” and “TSKgel SuperHZ4000” manufactured by Tosoh Corporation are connected in series Eluent: THF (tetrahydrofuran)
Eluent flow rate: 0.35ml/min Column temperature: 40°C
Detection method: Differential refractive index (RI) method

[Glass transition temperature (Tg)]
Measured in accordance with JIS K7121:2012. A differential scanning calorimetry (DSC) device (manufactured by Shimadzu Corporation; DSC-50) was used for the measurement. 5 mg of powder of multilayer structure polymer particles was accurately weighed and used as a sample. When measuring the DSC curve, the sample was heated once to 230°C, then cooled to -90°C, and then heated from -90°C to 230°C at a rate of 10°C/min. The midpoint glass transition temperature was determined from the DSC curve measured during the second temperature increase. The midpoint glass transition temperature was defined as the glass transition temperature (Tg).

[Graft rate]
2 g of powder of multilayer structure polymer particles was accurately weighed, and this was taken as the mass (W) of the sample. The precisely weighed powder was immersed in 118 g of acetone at 25° C. for 24 hours. Thereafter, by stirring the powder and acetone, the multilayer structure polymer particles were uniformly dispersed in acetone. Through the above steps, a liquid mixture was prepared.
Thereafter, 30 g of each of the preparations was aliquoted into four stainless steel centrifuge tubes. The centrifuge tube was weighed in advance. The centrifuge tube was centrifuged at 0° C. and 20,000 rpm for 90 minutes in a high-speed refrigerated centrifuge (manufactured by Hitachi, Ltd.: CR22GIII). The supernatant liquid was removed from each centrifuge tube by decantation. Thereafter, 30 g of acetone was newly added to each centrifuge tube. The precipitate and acetone were stirred. After centrifuging the centrifuge tube again, the supernatant was removed. Stirring, centrifugation, and supernatant removal were repeated four times in total. Through the above steps, acetone soluble components were sufficiently removed.
Thereafter, the precipitate was dried together with the centrifuge tube by vacuum drying. After drying, the precipitate was weighed to determine the mass of the acetone-insoluble component. The grafting rate of the multilayer structure polymer particles was calculated based on the following formula.
(Graft ratio) = {[(mass of acetone-insoluble component) - (mass of internal crosslinked product (inner layer))] / (mass of inner layer)} x 100
Here, the mass of the internal crosslinked material (inner layer) is the mass of the inner crosslinked rubber (I) layer, or the combined mass of the inner crosslinked rubber (I) and its inner layer (for example, crosslinked resin), and This is the total mass of components used to synthesize the internal crosslinked product (inner layer) of the structural polymer particles.

[Number average molecular weight of thermoplastic resin (II)]
The acetone-soluble component obtained in the measurement of the graft ratio was sufficiently dried, 10 mg was accurately weighed, 5 mL of THF (tetrahydrofuran) was added, and the mixture was stirred for 3 hours. evenly dispersed inside. The sample prepared above was measured by GPC under the above conditions to determine the number average molecular weight of the thermoplastic resin (II).

[Median diameter De]
An emulsion containing multilayer structure polymer particles obtained by emulsion polymerization was diluted 200 times with water. The aqueous dispersion was analyzed using a laser diffraction/scattering particle size distribution analyzer (manufactured by Horiba, Ltd.: LA-950V2), and the median diameter De was calculated from the analytical values. At this time, the refractive indices of the multilayer structure polymer particles and water were set to 1.4900 and 1.3333, respectively.

[Removal properties of multilayer polymer particles]
The emulsion containing the multilayer polymer particles was frozen and solidified in a -20°C freezer, washed with 80°C ion-exchanged water, and then dehydrated in a small centrifugal dehydrator (SYK-3800 manufactured by SANYO). Next, it was dried in a hot air dryer at 80° C., and the state of the coagulated product was judged according to the following criteria.
<Judgment criteria>
A (Good): Multilayer structure polymer particles can be taken out in a powder state.
B (normal): Multilayer structure polymer particles can be taken out in a block state.
C (bad): It is clay-like and it is difficult to take out the multilayer structure polymer particles, or the coagulated products block each other after drying.

[Thermal stability]
1 g of the thermoplastic resin composition was weighed out, wrapped in a cylindrical Teflon (registered trademark) sheet, and further sealed in a pressure-resistant tube made of SUS. This was heated at 270°C for 24 hours. The samples before and after the heating test were cut out using a microtome, and then stained with a phosphotungstic acid solution for 15 minutes, and the dispersion state of the multilayer polymer particles in the thermoplastic resin was observed using a TEM (manufactured by JEOL: JSM-7600F, magnification: ×10000). The dispersion state before and after heating was judged based on the following criteria. Note that the dispersion state was confirmed by looking at 100 multilayer structure polymer particles and making a judgment based on the following criteria.
<Judgment criteria>
A (good): The number of connected multilayer polymer particles is less than 10%. B (fair): The number of connected multilayer structure polymer particles is 10% or more and less than 20%. C (bad): The number of connected multilayer structure polymer particles is less than 10%. The number of structural polymer particles is 20% or more

[Dispersibility]
The pellets of the acrylic resin compositions obtained in Examples or Comparative Examples were extruded using a Capillograph (Model 1D, manufactured by Toyo Seiki Seisakusho Co., Ltd.) at an extrusion temperature of 270°C and a capillary with a diameter of 1 mm and a length of 40 mm at a piston speed of 10 mm. The strand extruded at a speed of 6 m/min was taken up by an attached melt tension measuring device at a take-up speed of 6 m/min, and after collecting 3 m of strands, the number of pieces was counted.
<Judgment criteria>
A (Good): The number of dots in 3 m of strand is less than 20. B (Normal): The number of dots in 3 m of strand is 20 or more and less than 50. C (Bad): The number of dots in 3 m of strand is 50. that's all

[Impact resistance]
The produced film was placed in an impact tester (manufactured by Yasuda Seiki Seisakusho: No. 181 Film Impact Tester), the energy when the film was broken was measured, and the impact resistance was evaluated from the value obtained by dividing the energy by the film thickness. .
The criteria for the indicators were as follows.
A (Good): Energy when breaking the film is 1.0 J/mm or more B (Bad): Energy when breaking the film is less than 1.0 J/mm

[Production Example 1: Production of multilayer structure polymer particles]
A reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a monomer inlet tube, and a reflux condenser tube was prepared. Into the reaction vessel, 733 parts by mass of ion-exchanged water, 0.09 parts by mass of polyoxyethylene (EO=3) tridecyl ether sodium acetate, and 0.5 parts by mass of sodium carbonate were charged. The inside of the reactor was sufficiently purged with nitrogen gas. Then, the internal temperature was brought to 80°C.
Separately, 175 parts by mass of a monomer mixture having the composition of the first layer shown in Table 1 was prepared. A first layer raw material was prepared by dissolving 1.23 parts by mass of polyoxyethylene (EO=3) tridecyl ether sodium acetate as an emulsifier in the monomer mixture. 0.17 parts by mass of potassium persulfate was charged into the reaction vessel, and then the raw material for the first layer was continuously added dropwise over 45 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 40 minutes. As described above, an emulsion containing the polymer component of the first layer was obtained.
Next, 0.225 parts by mass of potassium persulfate was charged into the same reactor. Separately, 225 parts by mass of a monomer mixture having the composition of the second layer shown in Table 1 was prepared. A second layer raw material was prepared by dissolving 0.59 parts by mass of polyoxyethylene (EO=3) tridecyl ether sodium acetate as an emulsifier in the monomer mixture. The emulsion obtained in the above step was stirred, and the raw material for the second layer was continuously added dropwise over 60 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 90 minutes to obtain an emulsion containing crosslinked rubber (I).
Next, 0.2 parts by mass of potassium persulfate was charged into the same reactor. Separately, 200 parts by mass of a monomer mixture having the composition of the third layer shown in Table 1 was prepared. The emulsion containing the crosslinked rubber (I) was stirred, and the monomer mixture having the composition of the third layer was continuously added dropwise over 50 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 80 minutes.
Through the above operations, an emulsion containing multilayer structure polymer particles in which a thermoplastic resin was graft-polymerized to a crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. By freezing the emulsion, the multilayer structure polymer particles were solidified. Next, the coagulated material was washed with water and dried to obtain a powder of multilayered polymer particles.

[Production Example 2: Production of multilayer polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Production Example 1 up to the first and second layers.
Next, 0.289 parts by mass of potassium persulfate was charged into the same reactor. Separately, 289 parts by mass of a monomer mixture having the composition of the third layer shown in Table 1 was prepared. The emulsion containing the crosslinked rubber (I) was stirred, and the monomer mixture having the composition of the third layer was continuously added dropwise over 75 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 115 minutes.
Through the above operations, an emulsion containing multilayer structure polymer particles in which a thermoplastic resin was graft-polymerized to a crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. By freezing the emulsion, the multilayer structure polymer particles were solidified. Next, the coagulated material was washed with water and dried to obtain a powder of multilayered polymer particles.

[Production Example 3: Production of multilayer polymer particles]
A powder of multilayer polymer particles was obtained in the same manner as Production Example 2, except that the compositions of the first layer, second layer, and third layer shown in Table 1 were changed.

[Production Example 4: Production of multilayer polymer particles]
A powder of multilayer polymer particles was obtained in the same manner as Production Example 2, except that the compositions of the first layer, second layer, and third layer shown in Table 1 were changed.

[Production Example 5: Production of multilayer structure polymer particles]
A powder of multilayer polymer particles was obtained in the same manner as Production Example 2, except that the compositions of the first layer, second layer, and third layer shown in Table 1 were changed.

[Production Example 6: Production of multilayer polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Production Example 1 up to the first and second layers.
Next, 0.1 part by mass of potassium persulfate was charged into the same reactor. Separately, 100 parts by mass of a monomer mixture having the composition of the third layer shown in Table 1 was prepared. The emulsion containing the crosslinked rubber (I) was stirred, and the monomer mixture having the composition of the third layer was continuously added dropwise over 25 minutes. After the completion of the dropwise addition, the polymerization reaction was further carried out for 45 minutes.
Through the above operations, an emulsion containing multilayer structure polymer particles in which a thermoplastic resin was graft-polymerized to a crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. By freezing the emulsion, the multilayer structure polymer particles were solidified. Next, the coagulated material was washed with water and dried to obtain a powder of multilayered polymer particles.

[Production Example 7: Production of multilayer polymer particles]
A reactor equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a monomer inlet tube, and a reflux condenser tube was prepared. Into the reaction vessel, 1,050 parts by mass of ion-exchanged water, 0.13 parts by mass of polyoxyethylene (EO=3) tridecyl ether sodium acetate, and 0.7 parts by mass of sodium carbonate were charged. The inside of the reactor was sufficiently purged with nitrogen gas. Then, the internal temperature was brought to 80°C.
Separately, 70 parts by mass of a monomer mixture having the composition of the first layer shown in Table 1 was prepared. A first layer raw material was prepared by dissolving 0.84 parts by mass of polyoxyethylene (EO=3) tridecyl ether sodium acetate as an emulsifier in the monomer mixture. 0.25 parts by mass of potassium persulfate was charged into the reaction vessel, and then the raw material for the first layer was continuously added dropwise over 60 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 30 minutes. As described above, an emulsion containing the polymer component of the first layer was obtained.
Then, 0.32 parts by mass of potassium persulfate was charged into the same reactor. Separately, 315 parts by mass of a monomer mixture having the composition of the second layer shown in Table 1 was prepared. A second layer raw material was prepared by dissolving 0.82 parts by mass of polyoxyethylene (EO=3) tridecyl ether sodium acetate as an emulsifier in the monomer mixture. The emulsion obtained in the above step was stirred, and the raw material for the second layer was continuously added dropwise over 60 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 90 minutes to obtain an emulsion containing crosslinked rubber (I).
Next, 0.14 parts by mass of potassium persulfate was charged into the same reactor. Separately, 315 parts by mass of a monomer mixture having the composition of the third layer shown in Table 1 was prepared. The emulsion containing the crosslinked rubber (I) was stirred, and the monomer mixture having the composition of the third layer was continuously added dropwise over 30 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 60 minutes.
Through the above operations, an emulsion containing multilayer structure polymer particles in which a thermoplastic resin was graft-polymerized to a crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. By freezing the emulsion, the multilayer structure polymer particles were solidified. Next, the coagulated material was washed with water and dried to obtain a powder of multilayered polymer particles.

[Production Example 8: Production of multilayer structure polymer particles]
Powder of multilayer polymer particles was obtained in the same manner as Production Example 7, except that the compositions of the first layer, second layer, and third layer shown in Table 1 were changed.

[Production Example 9: Production of multilayer polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Production Example 1 up to the first and second layers.
Next, 0.5 parts by mass of potassium persulfate was charged into the same reactor. Separately, 500 parts by mass of a monomer mixture having the composition of the third layer shown in Table 1 was prepared. The emulsion containing the crosslinked rubber (I) was stirred, and the monomer mixture having the composition of the third layer was continuously added dropwise over 125 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 60 minutes.
Through the above operations, an emulsion containing multilayer structure polymer particles in which a thermoplastic resin was graft-polymerized to a crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. By freezing the emulsion, the multilayer structure polymer particles were solidified. Next, the coagulated material was washed with water and dried to obtain a powder of multilayered polymer particles.

[Production Example 10: Production of multilayer structure polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Example 1 up to the first and second layers.
Next, 0.289 parts by mass of potassium persulfate was charged into the same reactor. Separately, 289 parts by mass of a monomer mixture having the composition of the third layer shown in Table 1 was prepared. The emulsion containing the crosslinked rubber (I) was stirred, and the monomer mixture having the composition of the third layer was continuously added dropwise over 75 minutes. After the dropwise addition was completed, the polymerization reaction was further carried out for 115 minutes.
Through the above operations, an emulsion containing multilayer structure polymer particles in which a thermoplastic resin was graft-polymerized to a crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. By freezing the emulsion, the multilayer structure polymer particles were solidified. Next, the coagulated material was washed with water and dried to obtain a powder of multilayered polymer particles.

[Production Example 11: Production of (meth)acrylic resin]
99.3 parts by mass of methyl methacrylate and 0.7 parts by mass of methyl acrylate were added with a polymerization initiator [2,2'-azobis(2-methylpropionitrile), hydrogen abstraction capacity: 1%, 1 hour half-life temperature: 83° C.] and 0.26 parts by mass of a chain transfer agent (n-octyl mercaptan) were added and dissolved to obtain 3000 kg of a raw material liquid.
100 parts by mass of ion-exchanged water, 0.03 parts by mass of sodium sulfate, and 0.45 parts by mass of a suspending and dispersing agent were mixed to obtain 6000 kg of a liquid mixture. The mixed solution and the raw material solution (9000 kg in total) were charged into a pressure-resistant polymerization tank, and the temperature was raised to 70° C. to initiate a polymerization reaction while stirring under a nitrogen atmosphere. Three hours after the start of the polymerization reaction, the temperature was raised to 90° C., and stirring was continued for one hour to obtain a liquid in which the bead-like copolymer was dispersed. Although some polymer adhered to the walls of the polymerization tank or the stirring blades, the polymerization reaction proceeded smoothly without bubbling.
The resulting copolymer dispersion was washed with an appropriate amount of ion-exchanged water, the bead-shaped copolymer was taken out using a bucket centrifuge, and the bead-shaped copolymer was dried in a hot air dryer at 80°C for 12 hours. ) Acrylic resin was obtained.
The obtained (meth)acrylic resin has a content of methyl methacrylate units of 99.3% by mass, a content of methyl acrylate units of 0.7% by mass, a number average molecular weight of 46,000, and a glass transition temperature. The temperature was 120°C.

In Table 1, V1-1 is the content (parts by mass) of the crosslinked hard body in the inner layer of the multilayer structure polymer particles, and V1-2 is the content (mass parts) of the crosslinked rubber (I) in the inner layer of the multilayer structure polymer particles. (parts), V2 represents the content (parts by mass) of the outer layer of the multilayer structure polymer particles. MMA, MA, ALMA, St, BzA, n-OM represent the content (mass%) in each layer of each monomer and chain transfer agent used to synthesize the polymer component of each layer.

[Example 1]
As the thermoplastic resin (III), 76 parts by mass of the (meth)acrylic resin of Production Example 11 and 24 parts by mass of the multilayer structure polymer particles (Production Example 1) were kneaded at 250°C for 3 minutes in a laboplasto mill (manufactured by Toyo Seiki Co., Ltd.). : Labo Plastomill 4C150) and further pulverized with a pulverizer to obtain an irregularly shaped granular thermoplastic resin composition. Further, a film with a thickness of 100 μm was obtained by hot press molding at 250° C. for 5 minutes. Using the obtained thermoplastic resin composition and film, thermal stability, dispersibility, and impact resistance were evaluated. The evaluation results are shown in Table 2.

[Examples 2 to 5, Comparative Examples 1 to 5]
Amorphous granular heat was produced in the same manner as in Example 1, except that the multilayer structure polymer particles used and the composition ratio of the thermoplastic resin (III) and the multilayer structure polymer particles were changed as shown in Table 2. A plastic resin composition and a 100 μm film were obtained, and their thermal stability, dispersibility, and impact resistance were evaluated. The evaluation results are shown in Table 2.

[Evaluation results]
Examples 1 to 5 showed good results in terms of thermal stability, dispersibility, and impact resistance. On the other hand, Comparative Example 1 using multilayer structure polymer particles with a low [V2/V1] of 0.25 resulted in insufficient thermal stability and dispersibility, and a multilayer structure with a high [V2/V1] of 0.82 Comparative Example 2 using structural polymer particles resulted in insufficient impact resistance. In addition, Comparative Example 3 uses multilayer structure polymer particles with a low [V2/V1] of 0.25, so thermal stability is insufficient, and Comparative Example 4 has a [V2/V1] of 1.25. The impact resistance was insufficient due to the use of highly multilayered polymer particles. Furthermore, Comparative Example 5, in which the outer layer used multilayered polymer particles with a low glass transition temperature, had poor take-out properties and poor dispersibility.

Claims (13)

A multilayer structure polymer particle having an inner layer containing a crosslinked rubber (I) and an outer layer containing a thermoplastic resin (II) graft-bonded to the inner layer,
The crosslinked rubber (I) contains 50 to 99.99% by mass of acrylic acid ester units, 0.01 to 5% by mass of polyfunctional monomer units, and 0 unsaturated monomer units copolymerizable with these. ~49.99% by mass,
The thermoplastic resin (II) graft-bonded with the inner layer contains 40 to 100% by mass of methyl methacrylate units and 0 to 60% by mass of methyl acrylate units,
The ratio [V2/V1] of the mass (V2) of the outer layer to the mass (V1) of the inner layer is 0.70 to 0.8,
Multilayer structure polymer particles, wherein the outer layer has a glass transition temperature of 80 to 120°C. 1. The thermoplastic resin (II) graft-bonded to the inner layer has a grafting ratio of 25 to 80 % by mass, expressed as a ratio of the mass of the thermoplastic resin (II) to the mass of the inner layer. The multilayer structure polymer particles described in . The multilayer structure polymer particles according to claim 1 or 2, having a median diameter of 80 to 500 nm as measured by a laser diffraction/scattering method. The multilayer structure polymer particles according to any one of claims 1 to 3, wherein the thermoplastic resin (II) graft-bonded to the inner layer has a number average molecular weight of 20,000 to 50,000. A thermoplastic resin composition containing 5 to 95% by mass of thermoplastic resin (III) and 5 to 95% by mass of the multilayer structure polymer particles according to any one of claims 1 to 4 . The thermoplastic resin composition according to claim 5 , wherein the thermoplastic resin (III) is an amorphous resin. The thermoplastic resin composition according to claim 5 or 6 , wherein the thermoplastic resin (III) has a glass transition temperature of 50 to 170°C. The thermoplastic resin composition according to any one of claims 5 to 7 , wherein the thermoplastic resin (III) has a number average molecular weight of 10,000 to 500,000. The thermoplastic resin composition according to any one of claims 5 to 8 , wherein the thermoplastic resin (III) is a (meth)acrylic resin. Any one of claims 5 to 9 , wherein the thermoplastic resin (III) is a (meth)acrylic resin containing 80 to 99.9% by mass of methacrylic ester units and 0.1 to 20% by mass of acrylic ester units. The thermoplastic resin composition according to item 1. A molded article made of the thermoplastic resin composition according to any one of claims 5 to 10 . A film comprising the thermoplastic resin composition according to any one of claims 5 to 10 . A molded article comprising the multilayer structure polymer particles according to any one of claims 1 to 4 .

Images