WO2020138501A1

WO2020138501A1 - Multilayer-structured polymer particle, and thermoplastic resin composition, molded body, and film including same

Info

Publication number: WO2020138501A1
Application number: PCT/JP2019/051629
Authority: WO
Inventors: 航平山下; 東田　昇; 大串　眞康; 香織前田
Original assignee: 株式会社クラレ
Priority date: 2018-12-28
Filing date: 2019-12-27
Publication date: 2020-07-02
Also published as: JPWO2020138501A1; JP7342033B2

Abstract

Provided is a multilayer-structured polymer particle having excellent long-term thermal stability in a matrix resin (base resin), and an excellent dispersibility and impact resistance in order to reduce defects in a molded body including a film. The multilayer-structured polymer particle has: an inner layer containing a cross-linked rubber (I); and an outer layer containing a thermoplastic resin (II) which is grafted with the inner layer, wherein the ratio [V2/V1] of the mass (V2) of the outer layer to the mass (V1) of the inner layer is 0.3-0.8, and the glass transition temperature of the outer layer is 80-120 °C.

Description

Multilayer polymer particles, thermoplastic resin composition containing the same, molded article and film

The present invention relates to multi-layered polymer particles, a thermoplastic resin composition containing the same, a molded article and a film.

The (meth)acrylic resin has excellent transparency, color tone, appearance, weather resistance, luster and processability and is therefore used in various fields. In particular, a film formed from a (meth)acrylic resin has high transparency, low moisture permeability, and easy primary processing and secondary processing, and is therefore widely used for optical applications, decoration applications, and the like.
Generally, an acrylic resin is brittle and lacks impact resistance, but a graft copolymer having a crosslinked rubber layer is blended with an acrylic resin to control the particle size of the graft copolymer having the crosslinked rubber layer. Therefore, impact resistance and strength are exhibited (Patent Document 1). In addition, molded articles such as films using a resin composition in which the graft copolymer having the rubber layer is mixed with an acrylic resin have been proposed (Patent Documents 2 and 3).
However, the above-mentioned molded product has a problem that when the molding temperature becomes high, many defects due to deterioration of the resin increase. As a method of reducing the spot defects, organic fine particles have been proposed which are obtained by further polymerizing a (meth)acrylic acid ester as a shell portion on a particulate polymer having a core portion having an average particle diameter of 0.01 μm to 1 μm. (Patent Document 4).

JP-A-48-55233 International Publication No. 2016/139927 International Publication No. 2017/204243 JP, 2007-254727, A

However, the methods disclosed in Patent Documents 1 to 4 may not be able to sufficiently reduce the spot defects of the molded product containing the film, and there is room for improvement in the multilayer structure polymer particles used.
In view of the above-mentioned circumstances, the present invention reduces the defects in a molded article including a film, and therefore 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 diligent studies on the above-mentioned problems, the present inventors have found that in order to improve long-term thermal stability, dispersibility and impact resistance, the mass ratio of each layer of the multilayer structure polymer particles and the glass transition temperature of the outer layer are important. As a result of further discovery based on these findings, the present invention has been achieved.
That is, the present invention is the following [1] to [14].
[1] 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 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 polymer particles having a glass transition temperature of 80 to 120° C. in the outer layer.
[2] Regarding the thermoplastic resin (II) graft-bonded to the inner layer, the graft ratio represented by the ratio of the mass of the thermoplastic resin (II) to the mass of the inner layer is 25 to 90 mass %. [1] The multilayer structure polymer particles described in [1].
[3] The multilayer-structured polymer particles according to [1] or [2], which has a median diameter of 80 to 500 nm measured by a laser diffraction/scattering method.
[4] The multilayer structure polymer 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. Coalesced particles.
[5] The crosslinked rubber (I) comprises an acrylic acid ester unit of 50 to 99.99% by mass, a polyfunctional monomer unit of 0.01 to 5% by mass, and an unsaturated monomer copolymerizable therewith. The thermoplastic resin (II) containing 0 to 49.99% by mass of the polymer unit and graft-bonded to the inner layer is 40 to 100% by mass of the methacrylic acid ester unit and another unsaturated monomer copolymerizable therewith. The multilayer-structured polymer particles according to any one of [1] to [4], which contains 0 to 60 mass% of a monomer unit.
[6] A thermoplastic resin composition containing 5 to 95% by mass of the 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 glass transition temperature of the thermoplastic resin (III) is 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 acid ester units and 0.1 to 20% by mass of acrylic acid ester units, [6] to The thermoplastic resin composition according to any one of [10].
[12] A molded product comprising the thermoplastic resin composition according to any one of [6] to [11].
[13] A film made of the thermoplastic resin composition according to any one of [6] to [11].
[14] A molded product containing the multilayer structured polymer particles according to any one of [1] to [5].

According to the present invention, it is possible to provide a multi-layer structure polymer particle which is excellent in long-term thermal stability in a matrix resin (base resin) and is excellent in dispersibility and impact resistance.

A multilayer structure polymer particle according to an embodiment of the present invention, wherein the inner layer is composed of one layer (first layer) and the outer layer is composed of two layers (second layer, third layer). It is a figure which shows a particle. A multilayer structure polymer particle according to an embodiment of the present invention, wherein the inner layer is composed of two layers (first layer and second layer) and the outer layer is composed of one layer (third layer). It is a figure which shows a particle. A multilayer structured polymer particle according to an embodiment of the present invention, wherein an inner layer is composed of two layers (first layer, second layer) and an outer layer is composed of two layers (third layer, fourth layer). It is a figure which shows a multilayer structure polymer particle. A multilayer structured polymer particle according to an embodiment of the present invention, wherein an inner layer is composed of two layers (first layer, second layer) and an outer layer is composed of two layers (third layer, fourth layer). It is a figure which shows a multilayer structure polymer particle.

The multi-layered polymer particle of the present invention is a multi-layered 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 ratio [V2/V1] of the mass (V2) of the outer layer to the mass (V1) is 0.3 to 0.8. [V2/V1] can be adjusted by the amount of the monomer mixture used for the polymerization of the inner layer and the outer layer of the multilayer structured polymer particles of the present invention. [V2/V1] of the multilayer polymer particles of the present invention is preferably 0.35 to 0.78, and more preferably 0.4 to 0.75. Within this range, the long-term thermal stability and impact resistance of the multi-layered polymer particles and the dispersibility of the multi-layered 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. If [V2/V1] is more than 0.8, the impact resistance may decrease. [V2/V1] is preferably 0.5 or more from the viewpoint of the decomposability of the crosslinked rubber in the matrix resin and the thermal stability in the retention part of the film of the multi-layered polymer particles during film formation. , 0.55 or more, more preferably 0.60 or more, still 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 “excellent removability”), and the multilayer structure in the matrix. The dispersibility of polymer particles is improved. When the glass transition temperature of the outer layer is lower than 80° C., blocking is likely to occur in the powder drying step, and it may be difficult to isolate the multilayer structure polymer particles. In addition, the dispersibility at the time of melt-kneading may decrease, and defects such as fish eyes may easily occur. Further, when the glass transition temperature is higher than 120° C., it becomes difficult to form an aggregate when the powder is taken out by the freeze-coagulation method, and it may be difficult to isolate the 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.
When the outer layer of the multi-layered polymer particles of the present invention has a glass transition temperature of 2 or more, the highest glass transition temperature is taken as the glass transition temperature of the outer layer, and the glass transition temperature in the present invention is as described in the examples. Indicates the value measured by the measuring method.

In the multi-layered polymer particles of the present invention, when the crosslinked rubber layer is one layer, the crosslinked rubber layer may be used alone or the crosslinked rubber layer and the inner layer may be referred to as an “inner layer”. The layer outside the rubber layer is called the “outer layer”. On the other hand, in the case of having two or more crosslinked rubber layers, the outermost crosslinked rubber layer and the layers inside the crosslinked rubber layer are collectively referred to as “inner layer”, and the layer outside the crosslinked rubber layer is referred to as “inner layer”. The outer layer”. Specific examples of the multilayer structured polymer particles of the present invention are illustrated in FIGS.
FIG. 1 is a multi-layered polymer particle having one crosslinked rubber layer, wherein the crosslinked rubber layer alone forms an inner layer, and a crosslinked PMMA (polymethylmethacrylate) layer and a PMMA outside the crosslinked rubber layer. It is a figure which shows the multilayer structure polymer particle which a layer comprises an outer layer. Further, FIG. 2 is a diagram showing a multilayer structure polymer particle in which a crosslinked rubber layer and a crosslinked PMMA layer inside thereof 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 multi-layered 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. is there.

The crosslinked rubber (I) is not particularly limited, and butadiene rubber, styrene/butadiene rubber, isoprene rubber, chloroprene rubber, acrylonitrile/butadiene rubber, butyl rubber, ethylene/propylene rubber, ethylene/propylene/diene rubber, urethane rubber, silicone rubber , Fluororubber, chlorosulfonated polyethylene rubber, acrylic rubber and the like, and acrylic rubber is particularly preferably used.

The acrylic rubber used for the crosslinked rubber (I) includes a structural unit derived from an acrylic acid ester (hereinafter sometimes referred to as an acrylic acid ester unit) and a structural unit derived from a polyfunctional monomer (a polyfunctional monofunctional unit). It is preferable to include a monomer unit).

Examples of the acrylic acid ester used for 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, 2-ethylhexyl acrylate and n-butyl acrylate are preferred, and n-butyl acrylate is preferred. More preferable. These may be used alone or in combination of two or more.

The content of the acrylate unit in the crosslinked rubber (I) is preferably 50 to 99.99% by mass, more preferably 60 to 99% by mass, and further preferably 70 to 98% by mass. .. Within this range, good impact resistance can be given.

Examples of the polyfunctional monomer used for 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 and the like, allyl acrylate and allyl methacrylate are preferable, and allyl methacrylate is more preferable. These may be used alone or in combination of two or more.

The content of the polyfunctional monomer unit 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. Within this range, the desired graft ratio can be achieved.

The crosslinked rubber (I) may further contain other unsaturated monomer copolymerizable with the above-mentioned acrylic acid ester or polyfunctional monomer, for example, 1,3-butadiene, 1,2-butadiene, Isoprene, styrene, α-methylstyrene, vinyltoluene, methylmethacrylate, ethylmethacrylate, n-butylmethacrylate, n-propylmethacrylate, i-propylmethacrylate, i-butylmethacrylate, t-butylmethacrylate, 2-ethylhexylmethacrylate, 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 unit 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 mass %.

The inner layer in the multi-layer structure polymer particles of the present invention may be a single layer containing a crosslinked rubber (I), or may be two or more layers each containing a crosslinked rubber (I) having a different composition. , May have one or more layers different in composition from the crosslinked rubber (I), but from the viewpoint of improving the strength of the multilayer structure polymer particles, the innermost layer containing the crosslinked hard body (for example, FIGS. And a 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).

The crosslinked hard body preferably contains a structural unit derived from a methacrylic acid ester (hereinafter, also referred to as a “methacrylic acid ester unit”). Specifically, as the methacrylic acid ester, a methacrylic acid ester whose ester portion is an alkyl group having 1 to 4 carbon atoms is preferable, and methyl methacrylate is particularly preferable.

The content of the methacrylic acid ester unit 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 0.0% by mass, and particularly preferably 80 to 97.0% by mass. When the content of the methacrylic acid ester unit is within this range, the strength of the multi-layer structure polymer particles can be improved.

Further, it is preferable that the crosslinked hard body contains a structural unit derived from an acrylate ester. Examples of the acrylate ester include esters in which the ester portion is a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Specifically, the same ones as those listed as the acrylic ester used for the crosslinked rubber (I) can be used, and the ester group has a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent. 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 the acrylate unit 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. It is more preferably 0% by mass. When the content of the acrylate unit is within this range, the impact resistance of the multi-layer structure polymer particles can be improved.

Further, 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 rigid 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 the polyfunctional monomer unit 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, it is easy to adjust the hardness to a desired level.

The thermoplastic resin (II) graft-bonded to the internal cross-linked product (inner layer) used in the multi-layered polymer particles of the present invention is not particularly limited, and may be polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyacetic acid. Examples thereof include vinyl, polyurethane, polytetrafluoroethylene, polyamide, polycarbonate, polyester, polyethylene terephthalate, polybutylene terephthalate, polyacetal, and (meth)acrylic resin, and (meth)acrylic resin is particularly preferably used.

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

The content of the methacrylic acid ester unit in the thermoplastic resin (II) graft-bonded to 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. Within this range, the strength of the multilayer structured polymer particles can be appropriately maintained.

The thermoplastic resin (II) which is graft-bonded to the inner layer can further include a structural unit derived from another unsaturated monomer copolymerizable with the monomer, and 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.
As the other unsaturated monomer used in the thermoplastic resin (II), one type may be used alone, or two or more types may be used in combination.

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

The method for producing the multi-layered polymer particles of the present invention is not particularly limited, but it is preferably produced by an emulsion polymerization method because of the ease of controlling the particle diameter, and specifically, for example, a crosslinked hard body and a crosslinked rubber ( In the case of a multilayer structure polymer particle having a three-layer structure in which I) and a thermoplastic resin (II) are laminated in this order, a polymerization reaction step (S1) for forming a crosslinked hard body, and a layer containing a crosslinked rubber (I) are formed. The polymerization reaction step (S2) and the polymerization reaction step (S3) for forming the layer containing the thermoplastic resin (II) can be carried out in this stacking order. Hereinafter, the case of producing the multi-layered polymer particles having the three-layered structure by an emulsion polymerization method will be described as an example.

[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 and a monomer. By mixing the mixture, the chain transfer agent and the like with water and heating the mixture, a polymerization reaction is carried out and an emulsion of a crosslinked hard body can be obtained.

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

[Polymerization reaction step (S3)]
After carrying out the polymerization reaction step (S2), a monomer mixture corresponding to the composition of the thermoplastic resin (II), a polymerization initiator, and a chain transfer agent are added (co)polymerized to give an emulsion of the present invention. Multilayered 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 and the like are used. it can. These emulsifiers can be used alone or in combination of two or more.
Examples of the anionic emulsifier include dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate and sodium dilauryl sulfosuccinate; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; and alkyl sulfates such as sodium dodecyl sulfate. ..
Examples of nonionic emulsifiers include polyoxyethylene alkyl ethers and polyoxyethylene nonylphenyl ethers.
Nonionic/anionic emulsifiers include polyoxyethylene nonylphenyl ether sulfate such as sodium polyoxyethylene nonylphenyl ether sulfate; polyoxyethylene alkyl ether sulfate such as sodium polyoxyethylene alkyl ether sulfate; polyoxyethylene tridecyl ether. Examples thereof 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 a reactive radical, and examples thereof include tert-hexylperoxyisopropyl monocarbonate and tert-hexylperoxy 2 -Ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, tert-butylperoxypivalate, tert-hexylperoxypivalate, tert-butylperoxy neodecanoe -To, tert-hexylperoxy neodecanoate, 1,1,3,3-tetramethylbutylperoxy neodecanoate, 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 Examples thereof include'-azobis(2-methylpropionate) and potassium persulfate. Of these, potassium persulfate is preferred.

The amount of the polymerization initiator is preferably 0.001 to 0.5 parts by mass with respect to 100 parts by mass of each monomer mixture in the polymerization reaction steps (S1) to (S3), and 0.01 It is more preferably from 0.4 to 0.4 parts by mass, further preferably from 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-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, ethylene. Glycol bisthiopropionate, butanediol bisthioglycolate, butanediol bisthiopropionate, hexanediol bisthioglycolate, hexanediol bisthiopropionate, trimethylolpropane tris-(β-thiopropionate) , Pentaerythritol tetrakisthiopropionate and the like. Of these, n-octyl mercaptan and n-dodecyl mercaptan are preferable, and n-octyl mercaptan is more preferable. These may be used alone or in combination of two or more.

Removal of the multi-layered polymer particles from the emulsion containing the multi-layered polymer particles obtained by the emulsion polymerization method, purification can be performed by a known method, for example, freeze-coagulation, it can be performed by washing with water, As a result, the multi-layer structure polymer particles of the present invention can be obtained.

In addition to the fact that the multi-layered polymer particles of the present invention have a [V2/V1] of 0.3 to 0.8, where V1 is the mass of the inner layer and V2 is the mass of the outer layer of the multi-layered polymer particles, The graft ratio is preferably 25 to 90% by mass. Therefore, the amount of the chain transfer agent used in the polymerization reaction step (S3) is preferably 100 parts by mass of the monomer mixture used in the step. It is 0.01 to 0.2 parts by mass, more preferably 0.02 to 0.0.18 parts by mass, still more preferably 0.03 to 0.17 parts by mass, and particularly preferably 0.05. To 0.15 parts by mass.
The amount of chain transfer agent used is preferably 1 to 199 parts by mass, more preferably 5 to 190 parts by mass, and even more preferably 100 parts by mass of the polymerization initiator used in the polymerization reaction step (S3). Is 10 to 150 parts by mass.

The graft ratio of the multi-layered polymer particles of the present invention is the same as the inner layer of the multi-layered polymer particles (for example, crosslinked rubber (I) and crosslinked resin) and the thermoplastic resin (II) graft-bonded 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 graft ratio (mass %) can be obtained by the method described in the examples.

The graft ratio of the multi-layered polymer particles of the present invention is preferably 25 to 90% by mass, more preferably 28 to 80% by mass, still more preferably 30 to 70% by mass, still more preferably 40. It is up to 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 graft ratio can be adjusted by the blending amount of the polyfunctional monomer, the blending amount of the chain transfer agent, and the like.

The median diameter De of the multi-layered polymer particles of the present invention measured with an emulsion by a laser diffraction/scattering method is preferably 80 to 500 nm, more preferably 150 to 400 nm, and more preferably 200 to 300 nm. More preferable. When the median diameter De of the multi-layered polymer particles is within the above range, required impact resistance can be obtained. Here, the median diameter De is the average value of the outer diameters of the multi-layered particle structure of the multi-layered polymer particles, and it can be specifically obtained 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 22,000. More preferably, it is -40,000. When the number average molecular weight of the thermoplastic resin (II) graft-bonded to the inner layer is within the above range, it is possible to obtain multi-layered polymer particles having excellent long-term thermal stability.

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 structure polymer particles. The number average molecular weight can be estimated from the number average molecular weight of the thermoplastic resin (II) not graft-bonded. 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 by the method described in 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 structured polymer particle of the present invention.

The present invention includes a thermoplastic resin composition containing the multilayer structure polymer particles and a thermoplastic resin (III) which can be a matrix resin (base resin).
As the thermoplastic resin (III), the same as those listed as the thermoplastic resin (II) can be used, but an amorphous resin is preferable. Examples of the amorphous resin used for the thermoplastic resin (III) include polyvinyl chloride, polystyrene, acrylonitrile/butadiene/styrene, polycarbonate, (meth)acrylic resin, and thermoplastic elastomer, and particularly (meth)acrylic resin. Resin is preferably used.

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

The multilayer-structured polymer particles of the present invention may be mixed in the thermoplastic resin (III) in the thermoplastic resin composition. Further, from the viewpoint of transportation and the like, the thermoplastic resin composition of the present invention may be molded into, for example, a pellet shape.

The thermoplastic resin composition of the present invention preferably contains the multilayer structure polymer particles in an amount of 5 to 95% by mass, more preferably 7 to 80% by mass, and further preferably 10 to 60% by mass. It is particularly preferable that the content is 15 to 50% by mass. Further, the thermoplastic resin composition of the present invention preferably contains the thermoplastic resin (III) in an amount of 5 to 95% by mass, more preferably 20 to 93% by mass, and further 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 further 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.
The glass transition temperature of the thermoplastic resin (III) refers to the value measured by the measuring method described in the 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 25,000 to 400,000. More preferably, it is particularly preferably 25,000 to 100,000. When the number average molecular weight of the thermoplastic resin (III) is within the above range, appropriate strength can be exhibited when the thermoplastic resin composition of the present invention is formed into a molded article such as a film.

The thermoplastic resin composition of the present invention, if necessary, and within a range that does not impair the effects of the present invention, an ultraviolet absorber, an antioxidant, a colorant, a fluorescent colorant, a dispersant, a heat stabilizer, and a light stabilizer. It may contain additives such as a stabilizer, an infrared absorber, an antistatic agent, a processing aid, a lubricant and a release agent. The colorant may be either a pigment or a dye. It may also contain a solvent.
The total content of the additives in the thermoplastic resin composition of the present invention is preferably 15 parts by mass or less when the total amount of the thermoplastic resin (III) and the multilayer structure polymer is 100 parts by mass. It is more preferably 10 parts by mass or less. The content of the ultraviolet absorber is preferably 0.1 to 4.0 parts by mass when the total amount of the thermoplastic resin (III) and the multilayer structure polymer is 100 parts by mass, and 0.2 parts by mass is preferable. It is more preferably at least 0.4 part by mass, further preferably at least 0.4 part by mass. Further, the content of the ultraviolet absorber is more preferably 3.8 parts by mass or less, and further preferably 3.5 parts by mass or less, from the viewpoint of suppressing the cost. Further, the content of the antioxidant is preferably 0.005 to 10 parts by mass, and 0.008 to 10 parts by mass, when the total amount of the thermoplastic resin (III) and the multilayer structure polymer is 100 parts by mass. The amount is more preferably 1 part by mass, further preferably 0.01 to 0.2 part by mass.

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

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
In Examples and Comparative Examples, the measurement of physical properties and the like were carried out by the following methods. Further, the abbreviations of the monomers and the like 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]
Based on the value measured using GPC (gel permeation chromatography), the molecular weight in terms of polystyrene was obtained. The measurement conditions were as follows.
Device: GPC device “HCL-8320” manufactured by Tosoh Corporation
Separation column: Tosoh Corporation “TTSKguradcolumn SuperHZ-H”, “TSKgel HZM-M” and “TSKgel SuperHZ4000” are connected in series Eluent: THF (tetrahydrofuran)
Eluent flow rate: 0.35 ml/min Column temperature: 40°C
Detection method: differential refractive index (RI) method

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

[Graft rate]
2 g of the powder of the multi-layered polymer particles was precisely weighed and used as the sample mass (W). The precisely weighed powder was immersed in 118 g of acetone at 25° C. for 24 hours. Then, the powder and acetone were stirred to uniformly disperse the multilayer structure polymer particles in acetone. The preparation liquid was prepared as described above.
Then, 30 g of the prepared liquid was dispensed into each of four stainless centrifuge tubes. The centrifuge tube was weighed in advance. The centrifuge tube was centrifuged for 90 minutes at 0° C. and 20,000 rpm in a high-speed cooling centrifuge (CR22GIII manufactured by Hitachi, Ltd.). The supernatant was removed from each centrifuge tube by decantation. Then, 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 4 times in total. As described above, the acetone-soluble component was sufficiently removed.
Then, the precipitate was dried by vacuum drying together with the centrifuge tube. The weight of the acetone-insoluble component was determined by weighing the precipitate after drying. The graft ratio of the multi-layer 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)}×100
Here, the mass of the inner crosslinked product (inner layer) is the mass of the inner layer crosslinked rubber (I) layer, or the inner layer crosslinked rubber (I) and its inner layer (for example, crosslinked resin). It is the total mass of the components used to synthesize the crosslinked product (inner layer) inside the structural polymer particles.

[The number average molecular weight of the thermoplastic resin (II)]
The acetone-soluble component obtained in the measurement of the graft ratio was sufficiently dried, 10 mg was precisely weighed, 5 mL of THF (tetrahydrofuran) was added, and the mixture was stirred for 3 hours to remove the acetone-soluble component of the multilayer polymer particles from THF. Dispersed evenly throughout. The sample produced as described above was measured by GPC under the above conditions, and the number average molecular weight of the thermoplastic resin (II) was measured.

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

[Removability of multi-layered polymer particles]
The emulsion containing multi-layered polymer particles was freeze-coagulated in a freezer at −20° C., washed with ion-exchanged water at 80° C., and then dehydrated with a small centrifugal dehydrator (SANK: SYK-3800). Then, it was dried with a warm air dryer at 80° C., and the state of the coagulated product was judged according to the following judgment criteria.
<Judgment criteria>
A (good): The multilayer structure polymer particles can be taken out in the powder state.
B (normal): The multilayer structure polymer particles can be taken out in a block state.
C (bad): It is difficult to take out the multi-layered polymer particles in the form of clay, or the solidified materials block each other after drying.

[Thermal stability]
1 g of the thermoplastic resin composition was weighed, wrapped in a tubular Teflon (registered trademark) sheet, and further enclosed 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 with a microtome and then dyed with a phosphotungstic acid solution for 15 minutes, and the dispersion state of the multilayer structure polymer particles in the thermoplastic resin was observed by TEM (JEOL: JSM-7600F, magnification: ×10000). The dispersion state before and after heating was judged according to the following criteria. The dispersed state was confirmed by observing 100 multi-layer structure polymer particles and observing the following criteria.
<Judgment criteria>
A (good): the number of continuous multi-layered polymer particles is less than 10% B (normal): the number of continuous multi-layered polymer particles is 10% or more and less than 20% C (bad): continuous multi-layer The number of structural polymer particles is 20% or more

[Dispersibility]
For the pellets of the acrylic resin composition obtained in Examples or Comparative Examples, using a capillograph (manufactured by Toyo Seiki Seisakusho Co., Ltd. Model 1D), an extrusion temperature of 270° C., a diameter of 1 mm, and a length of 40 mm were used, and the piston speed was 10 mm. The strand extruded at a speed of 6 m/min was taken at a take-up speed of 6 m/min by an attached melt tension measuring device, 3 m of the strand was sampled, and then the number of spots was counted.
<Judgment criteria>
A (good): The number of butts in the strand 3m is less than 20 B (ordinary): The number of butts in the strand 3m is 20 or more and less than 50 C (bad): The number of butts in the strand 3m is 50 that's all

[Impact resistance]
The produced film was placed on an impact tester (Yasuda Seiki Seisakusho: No. 181 film impact tester), the energy at the time of breaking the film 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 are as follows.
A (good): energy when the film is broken is 1.0 J/mm or more B (bad): energy when the film is broken is less than 1.0 J/mm

[Production Example 1: Production of multi-layer structure polymer particles]
A reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction pipe, a monomer introduction pipe and a reflux cooling pipe was prepared. Into such a reaction vessel, 733 parts by mass of ion-exchanged water, 0.09 parts by mass of sodium polyoxyethylene (EO=3) tridecyl ether acetate, and 0.5 parts by mass of sodium carbonate were charged. The inside of the reactor was sufficiently replaced with nitrogen gas. Then, the internal temperature was set 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. The first layer raw material was prepared by dissolving 1.23 parts by mass of sodium polyoxyethylene (EO=3) tridecyl ether acetate as an emulsifier in the monomer mixture. 0.17 parts by mass of potassium persulfate was put into the reaction vessel, and then the first layer raw material was continuously added dropwise over 45 minutes. After the dropping was completed, the polymerization reaction was performed for 40 minutes. Thus, an emulsion containing the polymer component of the first layer was obtained.
Next, 0.225 parts by mass of potassium persulfate was put 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. The second layer raw material was prepared by dissolving 0.59 parts by mass of sodium polyoxyethylene (EO=3) tridecyl ether acetate as an emulsifier in the monomer mixture. The emulsion obtained in the above step was stirred, and the second layer raw material was continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 90 minutes to obtain an emulsion containing the crosslinked rubber (I).
Next, 0.2 part by mass of potassium persulfate was put into the 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 dropping was completed, the polymerization reaction was further performed for 80 minutes.
By the above operation, an emulsion containing multi-layered polymer particles in which the thermoplastic resin was graft-polymerized on the crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. The multilayer structure polymer particles were solidified by freezing the emulsion. Next, the coagulated product was washed with water and dried to obtain a powder of multi-layer structure polymer particles.

[Production Example 2: Production of multi-layered polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Production Example 1 up to the first layer and the second layer.
Next, 0.289 parts by mass of potassium persulfate was charged into the 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 dropping was completed, the polymerization reaction was further performed for 115 minutes.
By the above operation, an emulsion containing multi-layered polymer particles in which the thermoplastic resin was graft-polymerized on the crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. The multi-layered polymer particles were solidified by freezing the emulsion. Next, the coagulated product was washed with water and dried to obtain a powder of multi-layer structure polymer particles.

[Production Example 3: Production of multi-layer structure polymer particles]
Powders of multi-layered polymer particles were obtained in the same manner as in Production Example 2 except that the compositions of the first layer, the second layer and the third layer shown in Table 1 were changed.

[Production Example 4: Production of multi-layered polymer particles]
Powders of multi-layered polymer particles were obtained in the same manner as in Production Example 2 except that the compositions of the first layer, the second layer and the third layer shown in Table 1 were changed.

[Production Example 5: Production of multi-layered polymer particles]
Powders of multi-layered polymer particles were obtained in the same manner as in Production Example 2 except that the compositions of the first layer, the second layer and the third layer shown in Table 1 were changed.

[Production Example 6: Production of multi-layered polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Production Example 1 up to the first layer and the second layer.
Next, 0.1 part by mass of potassium persulfate was charged into the 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 dropping was completed, the polymerization reaction was further performed for 45 minutes.
By the above operation, an emulsion containing multi-layered polymer particles in which the thermoplastic resin was graft-polymerized on the crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. The multi-layered polymer particles were solidified by freezing the emulsion. Next, the coagulated product was washed with water and dried to obtain a powder of multi-layer structure polymer particles.

[Production Example 7: Production of multi-layer structure polymer particles]
A reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction pipe, a monomer introduction pipe and a reflux cooling pipe was prepared. In such a reaction vessel, 1,050 parts by mass of ion-exchanged water, 0.13 parts by mass of sodium polyoxyethylene (EO=3) tridecyl ether acetate, and 0.7 parts by mass of sodium carbonate were charged. The inside of the reactor was sufficiently replaced with nitrogen gas. Then, the internal temperature was set 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. The first layer raw material was prepared by dissolving 0.84 parts by mass of sodium polyoxyethylene (EO=3) tridecyl ether acetate as an emulsifier in the monomer mixture. 0.25 parts by mass of potassium persulfate was put into the reaction vessel, and then the first layer raw material was continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was performed for another 30 minutes. Thus, an emulsion containing the polymer component of the first layer was obtained.
Next, 0.32 parts by mass of potassium persulfate was charged into the reactor. Separately, 315 parts by mass of a monomer mixture having the composition of the second layer shown in Table 1 was prepared. The second layer raw material was prepared by dissolving 0.82 parts by mass of sodium polyoxyethylene (EO=3) tridecyl ether acetate as an emulsifier in the monomer mixture. The emulsion obtained in the above step was stirred, and the second layer raw material was continuously added dropwise over 60 minutes. After the dropping was completed, the polymerization reaction was further performed for 90 minutes to obtain an emulsion containing the crosslinked rubber (I).
Next, 0.14 parts by mass of potassium persulfate was charged into the 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 dropping was completed, the polymerization reaction was further performed for 60 minutes.
By the above operation, an emulsion containing multi-layered polymer particles in which the thermoplastic resin was graft-polymerized on the crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. The multi-layered polymer particles were solidified by freezing the emulsion. Next, the coagulated product was washed with water and dried to obtain a powder of multi-layer structure polymer particles.

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

[Production Example 9: Production of multi-layered polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Production Example 1 up to the first layer and the second layer.
Next, 0.5 part by mass of potassium persulfate was charged into the 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 dropping was completed, the polymerization reaction was further performed for 60 minutes.
By the above operation, an emulsion containing multi-layered polymer particles in which the thermoplastic resin was graft-polymerized on the crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. The multi-layered polymer particles were solidified by freezing the emulsion. Next, the coagulated product was washed with water and dried to obtain a powder of multi-layer structure polymer particles.

[Production Example 10: Production of multi-layered polymer particles]
An emulsion containing a crosslinked rubber polymer was obtained in the same manner as in Example 1 up to the first layer and the second layer.
Next, 0.289 parts by mass of potassium persulfate was charged into the 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 dropping was completed, the polymerization reaction was further performed for 115 minutes.
By the above operation, an emulsion containing multi-layered polymer particles in which the thermoplastic resin was graft-polymerized on the crosslinked rubber was obtained. Using the obtained emulsion, the removability was evaluated. The multi-layered polymer particles were solidified by freezing the emulsion. Next, the coagulated product was washed with water and dried to obtain a powder of multi-layer structure polymer particles.

[Production Example 11: Production of (meth)acrylic resin]
Polymerization initiator [2,2'-azobis(2-methylpropionitrile)] in 99.3 parts by mass of methyl methacrylate and 0.7 parts by mass of methyl acrylate, hydrogen abstraction ability: 1%, 1 hour half-life temperature: 83° C.] 0.008 parts by mass and a chain transfer agent (n-octyl mercaptan) 0.26 parts by mass were added and dissolved to obtain 3000 kg of a raw material liquid.
100 parts by mass of ion-exchanged water, 0.03 part by mass of sodium sulfate, and 0.45 part by mass of a suspension dispersant were mixed to obtain a mixed solution of 6000 kg. The mixed liquid and the raw material liquid (total of 9000 kg) were charged into a pressure resistant polymerization tank, and the temperature was raised to 70° C. to start the polymerization reaction while stirring in a nitrogen atmosphere. After 3 hours had elapsed from the start of the polymerization reaction, the temperature was raised to 90° C. and stirring was continued for 1 hour to obtain a liquid in which the bead-like copolymer was dispersed. Although some polymer adhered to the wall of the polymerization tank or the stirring blade, the polymerization reaction proceeded smoothly without foaming.
The obtained copolymer dispersion was washed with an appropriate amount of ion-exchanged water, and the bead-shaped copolymer was taken out by a bucket centrifuge and dried in a hot air dryer at 80° C. for 12 hours to give a bead-shaped (meta ) An acrylic resin was obtained.
The obtained (meth)acrylic resin had a methyl methacrylate unit content of 99.3% by mass, a methyl acrylate unit content of 0.7% by mass, a number average molecular weight of 46,000, and a glass transition temperature of It was 120°C.

In Table 1, V1-1 is the content (mass part) of the crosslinked hard body in the inner layer of the multilayer structure polymer particles, and V1-2 is the content (mass of the crosslinked rubber (I) of the inner layer of the multilayer structure polymer particles). Part) and V2 represent the content (parts by mass) of the outer layer of the multilayer structure polymer particles. MMA, MA, ALMA, St, BzA, and n-OM represent the content (% by mass) of each monomer and chain transfer agent used for synthesizing the polymer component of each layer in 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 with a Labo Plastomill at 250° C. for 3 minutes (manufactured by Toyo Seiki Co., Ltd.). : Labo Plastomill 4C150) and further pulverized by a pulverizer to obtain an amorphous thermoplastic resin composition in granular form. A film having 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 particles were formed 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) to the multilayer structure polymer particles were changed as shown in Table 2. A plastic resin composition and a film having a thickness of 100 μm were obtained, and thermal stability, dispersibility, and impact resistance were evaluated. The evaluation results are shown in Table 2.

[Evaluation results]
In Examples 1 to 5, good results were obtained in terms of thermal stability, dispersibility, and impact resistance. On the other hand, Comparative Example 1 using the multi-layered polymer particles having a low [V2/V1] of 0.25 resulted in insufficient thermal stability and dispersibility, resulting in a high [V2/V1] of 0.82. Comparative Example 2 using the structural polymer particles resulted in insufficient impact resistance. Further, Comparative Example 3 uses multilayer structure polymer particles having a low [V2/V1] of 0.25, and thus has insufficient thermal stability, and Comparative Example 4 has a [V2/V1] of 1.25. Since high polymer particles having a multi-layer structure are used, the impact resistance is insufficient. Further, in Comparative Example 5 using the polymer particles having a multi-layer structure having a low glass transition temperature of the outer layer, the removability and dispersibility were poor.

Claims

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 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 polymer particles having a glass transition temperature of 80 to 120° C. in the outer layer.
The thermoplastic resin (II) graft-bonded to the inner layer has a graft ratio represented by the ratio of the mass of the thermoplastic resin (II) to the mass of the inner layer of 25 to 90 mass %. The multi-layered polymer particles described in.
The multilayer structure polymer particle according to claim 1 or 2, which has a median diameter of 80 to 500 nm 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.
The crosslinked rubber (I) contains 50 to 99.99% by mass of an acrylic acid ester unit, 0.01 to 5% by mass of a polyfunctional monomer unit, and an unsaturated monomer unit 0 copolymerizable therewith. Up to 49.99% by mass,
The thermoplastic resin (II) graft-bonded to the inner layer contains 40 to 100% by mass of a methacrylic acid ester unit and 0 to 60% by mass of another unsaturated monomer unit copolymerizable therewith. Item 5. The multilayer structured polymer particle according to any one of items 1 to 4.
A thermoplastic resin composition containing 5 to 95% by mass of the thermoplastic resin (III) and 5 to 95% by mass of the multilayer structure polymer particles according to any one of claims 1 to 5.
The thermoplastic resin composition according to claim 6, wherein the thermoplastic resin (III) is an amorphous resin.
The thermoplastic resin composition according to claim 6 or 7, wherein the glass transition temperature of the thermoplastic resin (III) is 50 to 170°C.
The thermoplastic resin composition according to any one of claims 6 to 8, 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 6 to 9, wherein the thermoplastic resin (III) is a (meth)acrylic resin.
Any of claims 6 to 10, wherein the thermoplastic resin (III) is a (meth)acrylic resin containing 80 to 99.9% by mass of a methacrylic acid ester unit and 0.1 to 20% by mass of an acrylic acid ester unit. 2. The thermoplastic resin composition according to item 1.
A molded body made of the thermoplastic resin composition according to any one of claims 6 to 11.
A film made of the thermoplastic resin composition according to any one of claims 6 to 11.
A molded body containing the multilayer structured polymer particles according to any one of claims 1 to 5.