JP2003128736A - Acrylic resin particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain acrylic resin particles excellent in handling and flexibility at normal temperature. SOLUTION: The acrylic resin particles having a multilayer structure consisting of an inner layer mainly comprising an acrylic acid ester copolymer having <=0 deg.C glass transition temperature and an outer layer mainly comprising a methacrylic acid ester copolymer having >=60 deg.C glass transition temperature are produced by polymerizing the methacrylic acid ester-containing monomer to obtain the resin having >=60 deg.C glass transition temperature to be the outer layer, subsequently dissolving the resin in the acrylic acid ester-containing monomer to be the inner layer to obtain a solution which is polymerized in suspension.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to acrylic resin particles having a multi-layer structure, and more specifically, it has an impact resistance modifier which is blended with other resins and has excellent handleability at room temperature in addition to flexibility. In addition, the present invention relates to acrylic resin particles that can be used for soft materials, hot melt adhesives, laminating resins, pressure-sensitive adhesives, and the like.

[0002]

2. Description of the Related Art Thermoplastic acrylic resins, such as methacrylic acid ester resins, are particularly excellent in weather resistance and transparency, but have a drawback that they are inferior in impact resistance due to insufficient flexibility. In order to improve the impact resistance of not only such a methacrylic acid ester-based resin but also a hard resin, a method is known in which a modifier made of a resin having a low glass transition point is kneaded and molded. . However,
A modifier composed of a resin having a glass transition point of 0 ° C. or lower is effective for improving impact resistance, but at room temperature, the modifier particles block (aggregate) in a sheet form,
As it is, it has a drawback that it cannot be used by being put into a molding machine such as an injection molding machine or an extruder via the hopper.

Further, some acrylic ester resins are used for adhesives, but due to their low glass transition temperature, the resins are sticky and the resin alone is not easy to handle. There are drawbacks.

In order to solve these problems, various methods have heretofore been proposed. For example, Japanese Patent Laid-Open No. 3-1
As described in JP-A-5648, multi-layered structure particles are polymerized by emulsion polymerization, the inner layer of the particles is a crosslinked elastic body mainly composed of an acrylic ester resin, and the outer layer is a hard methacrylate ester resin. , Those with improved handling have been proposed. However, this multi-layer structure particle has a drawback that it has poor fluidity when heated and melted due to its cross-linked structure, and also has a drawback that the emulsifier remaining in the emulsion polymerization adversely affects the quality of the adhesive and the molded product. is there.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art. In addition to having flexibility, it also has excellent handling properties at room temperature, and therefore has impact resistance to be blended with other resins. Another object of the present invention is to provide acrylic resin particles which can be preferably used for soft material applications, hot melt adhesives, laminating resins, pressure-sensitive adhesives, etc. in addition to the property modifier.

[0006]

In order to solve such a problem, the invention according to claim 1 provides an inner layer mainly composed of an acrylic acid ester copolymer having a glass transition temperature of 0 ° C. or lower,
It is an acrylic resin particle having a multilayer structure composed of an outer layer mainly composed of a methacrylic acid ester copolymer having a glass transition temperature of 60 ° C or higher.

According to a second aspect of the present invention, the methacrylic acid ester copolymer of the outer layer contains a monomer having hydrophilicity of 0.
The acrylic resin particles according to claim 1, wherein the acrylic acid ester copolymer of 5% by weight or more is copolymerized, and the acrylic acid ester copolymer of the inner layer is copolymerized with a monomer having hydrophilicity less than the copolymerization rate in the outer layer. . The invention according to claim 3 is the acrylic resin particle according to claim 1 or 2, wherein the weight ratio of the inner layer to the outer layer is 50/50 to 95/5.

The invention according to claim 4 is to obtain a resin having a glass transition temperature of 60 ° C. or higher for forming an outer layer by polymerizing a monomer containing a methacrylic acid ester, and then using this resin for forming an acrylic ester as an inner layer. Is dissolved in a monomer containing a to prepare a solution, and this solution is subjected to suspension polymerization to obtain a glass transition temperature of 0 ° C.
A method for producing acrylic resin particles having a multi-layer structure comprising an inner layer mainly composed of the following acrylic acid ester copolymer and an outer layer mainly composed of the methacrylic acid ester copolymer having a glass transition temperature of 60 ° C. or higher. The invention according to claim 5 is a resin composition containing the acrylic resin particles according to any one of claims 1 to 3.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on embodiments. The acrylic resin particles of the present invention are multilayer particles having an inner and outer layer structure, the inner layer is made of a resin containing an acrylic acid ester copolymer and having a glass transition temperature of 0 ° C. or lower, and the outer layer is a methacrylic acid ester copolymer. It is a multi-layered particle made of a resin containing a polymer and having a glass transition temperature of 60 ° C. or higher.

In the present invention, the glass transition temperature of the acrylic acid ester copolymer constituting the inner layer is preferably 0 ° C or lower, more preferably -10 ° C or lower. When the glass transition temperature is 0 ° C or higher, the effects such as flexibility and impact resistance are not sufficient.

The methacrylic acid ester copolymer constituting the outer layer has a glass transition temperature of 60 ° C. or higher, preferably 70 ° C. or higher. When the glass transition temperature is 60 ° C. or lower, the handleability at room temperature is deteriorated.

In the present invention, the monomers of acrylic acid ester and methacrylic acid ester used in the acrylic acid ester copolymer and the methacrylic acid ester copolymer forming the inner layer and the outer layer are, for example, methyl methacrylate, ethyl methacrylate, Propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylamino methacrylate. Methacrylic acid and its derivatives such as ethyl and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate. , 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl, and the like of acrylic acid and its derivatives phenyl acrylate and the like.

Water-soluble monomers can be used as the hydrophilic monomer to be copolymerized with the acrylic ester copolymer and the methacrylic ester copolymer forming the inner layer and the outer layer in the present invention. As the water-soluble monomer, at least one acid group and / or its salt-forming group [carboxylic acid (salt) group, sulfonic acid (salt) group, sulfuric acid (salt) group, phosphoric acid (salt) group, etc.] , A hydroxyl group, an amide group, an amino group, a monomer having a hydrophilic group such as a quaternary ammonium salt group,
It can be classified into anionic, nonionic and cationic monomers.

Anionic or anionic monomers having a carboxylic acid group include unsaturated monocarboxylic acids such as (meth) acrylic acid, crotonic acid, cinnamic acid, etc .; unsaturated dicarboxylic acids. , For example, maleic acid, fumaric acid, citraconic acid, itaconic acid; monoalkyl (C1-8) esters of unsaturated dicarboxylic acids (above), such as maleic acid monobutyl ester, fumaric acid monobutyl ester, maleic acid Examples thereof include carboxyl group-containing vinyl monomers such as ethyl carbitol monoester, fumaric acid ethyl carbitol monoester, citraconic acid monobutyl ester, and itaconic acid glycol monoester.

As the monomer having a sulfonic acid group, an aliphatic or aromatic vinyl sulfonic acid having 2 to 30 carbon atoms, for example, vinyl sulfonic acid, (meth) allyl sulfonic acid; styrene sulfonic acid, α-methylstyrene sulfone Acid; (meth) acrylalkyl sulfonic acids [(meth)
Acryloxypropyl sulfonic acid, 2-hydroxy-3
-(Meth) acryloxypropylsulfonic acid, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, 3- (meth) acryloxyethanesulfonic acid,
2- (meth) acrylamido-2-methylpropanesulfonic acid, 3- (meth) acrylamido-2-hydroxypropanesulfonic acid]; alkyl (having 3 to 18 carbon atoms)
(Meth) allyl sulfosuccinate and the like can be mentioned.

Examples of the monomer having a sulfate ester include a hydroxyalkyl (C 2-6) (meth) acrylate sulfate ester compound [hydroxyethyl (meth) acrylate sulfate ester compound and the like]; poly (n = 2 to Three
0) Sulfonates of oxyalkylene (having 2 to 4 carbon atoms: single, random, or block) mono (meth) acrylates [poly (n = 5 to 15) oxypropylene monomethacrylate sulfates, etc.] and the like. .

Examples of the monomer having a phosphoric acid group include, for example,
Hydroxyalkyl (meth) acrylate (C2-C2
6) Phosphoric acid monoester [eg, hydroxyethyl (meth) acrylate monophosphate, etc.], Phosphoric acid diester of hydroxyalkyl (meth) acrylate (having 2 to 6 carbon atoms) [eg, phenyl-2-acryloyloxyethyl phosphate] Etc.], alkyl (meth) acrylate (having 2 to 6 carbon atoms) phosphonic acids [eg, 2-acryloyloxyethylphosphonic acid, etc.] and the like.

The nonionic monomer having a hydroxyl group is, for example, a monoethylenically unsaturated alcohol [eg (meth) allyl alcohol]; a divalent to hexavalent or higher polyol ( For example, C2-C20 alkylene glycol, glycerin, polyalkylene (C2-C4) glycol (molecular weight 106-200).
0) etc.) monoethylenically unsaturated esters or ethers [eg hydroxyethyl (meth) acrylate,
Hydroxypropyl (meth) acrylate, triethylene glycol (meth) acrylate, poly-oxyethylene-oxypropylene (random or block) glycol mono (meth) allyl ether (terminal hydroxyl group may be etherified or esterified) Etc.] and the like.

Examples of the amide group-containing monomer include (meth) acrylamide and N-alkyl (having 1 carbon atom).
To 8) (meth) acrylamide [eg, N-methylacrylamide, etc.], N, N-dialkyl (having 1 to 1 carbon atoms)
8) Acrylamide [for example, N, N-dimethylacrylamide, N, N-di-n- or i-propylacrylamide, etc.], N-hydroxyalkyl (having 1 to 1 carbon atoms)
8) (meth) acrylamide [for example, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc.]; N, N-dihydroxyalkyl (having 1 to 8 carbon atoms) (meth) acrylamide [for example, N, N-dihydroxyethyl (meth) acrylamide etc.], vinyl lactams [eg N-vinylpyrrolidone etc.] and the like can be mentioned.

Examples of the cationic or cationic monomer having an amino group include an amino group-containing ester of monoethylenically unsaturated mono- or di-carboxylic acid such as dialkyl (having 1 to 8 carbon atoms). ) Aminoalkyl (C2-10) (meth) acrylate, dihydroxyalkyl (C1-8) aminoalkyl (C2)
-10) ester, morpholino alkyl (C1-C1
8) Esters and the like [eg, dimethylaminoethyl (meth) acrylate, diethylamino (meth) acrylate, morpholinoethyl (meth) acrylate, dimethylaminoethyl fumarate, etc.]; monoethylenically unsaturated mono- or di-carboxylic acid amino Group-containing amide,
For example, monoalkyl (carbon number 2 to 10) (meth) acrylamide and the like [eg, dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide and the like]; heterocyclic vinyl compound [eg, 2-vinylpyridine, 4- Vinylpyridines, vinylpyridines such as N-vinylpyridine, N-vinylimidazole, etc.];
Examples include diallylamine and the like.

As the monomer having a quaternary ammonium group, a quaternized product of a vinyl monomer containing a tertiary amino group (the vinyl monomer containing a tertiary amino group is an alkyl group having 1 to 8 carbon atoms). Quaternizing agents such as methyl chloride, dimethyl sulfate, benzyl chloride, dimethyl carbonate, and the like), for example, trimethylaminoethyl (meth) acrylate chloride, methyldiethylaminoethyl (meth) acrylate Methosulfate, trimethylaminoethyl (meth) acrylamide chloride, diethylbenzylaminoethyl (meth)
Examples include acrylamide and chloride.

Among these, preferred are monomers having a carboxylic acid (salt) group, a sulfonic acid (salt) group, and an amide group, and particularly preferably (meth) acrylic acid (salt),
It is (meth) acrylamide. These monomers may be used alone, or if necessary, two or more kinds may be used in combination.

In addition to these, the acrylic ester copolymer to be the inner layer and the methacrylic ester copolymer to be the outer layer of the present invention include, for example, styrene and α.
-Styrenes such as methylstyrene, vinyltoluene and hydroxystyrene, and monomers such as glycidyl acrylate, glycidyl methacrylate and acrylonitrile can be copolymerized.

When the content (copolymerization rate) of the hydrophilic monomer in the outer layer is less than 0.5% by weight, it becomes difficult to form the methacrylic acid ester copolymer in the outer layer.
Further, even if this content (copolymerization rate) is 0.5% by weight or more, the content (copolymerization rate) of the hydrophilic monomer in the inner layer is equal to that of the hydrophilic monomer in the outer layer. When the content exceeds the above range, it becomes difficult to form the methacrylic acid ester copolymer in the outer layer.

The ratio of the inner layer to the outer layer of the acrylic resin particles of the present invention, that is, the weight ratio of the inner layer / outer layer is 50/50 to 95.
/ 5, preferably 60/40 to 90/10. If the ratio of the inner layer is too small, the effect of flexibility becomes small, and if it is too large, the handleability becomes poor.

Further, in the present invention, additives such as an ultraviolet absorber, a stabilizer and a colorant are added to each of the copolymers forming the inner layer and the outer layer within a range that does not change the essential properties of the acrylic resin particles. be able to.

Next, a method for producing the acrylic resin particles of the present invention will be described. First, a monomer containing a methacrylic acid ester to be an outer layer is polymerized to have a glass transition temperature of 60.
Produce a polymer that is above ° C. Polymerization methods such as emulsion polymerization, suspension polymerization and solution polymerization can be adopted for the polymerization of this polymer.

Next, the resin to be the outer layer is dissolved in the monomer containing the acrylic ester to be the inner layer.
A polymerization initiator is added to a solution in which a resin to be the outer layer is dissolved. Then, this solution is suspension-polymerized.

As a result, a thermoplastic resin having a multilayer structure in which a soft acrylate copolymer having a glass transition temperature of 0 ° C. or less is formed in the inner layer and a hard methacrylic acid ester copolymer having a glass transition temperature of 60 ° C. or more is formed in the outer layer Acrylic resin particles of are obtained.

Since the resin particles are present in the dispersion liquid, they can be successively washed, dehydrated, and dried to produce acrylic resin particles which are solid and excellent in handleability. In this production method, by producing the resin particles by suspension polymerization, it is possible to obtain large particles having no emulsifier and having a particle size of several μm to 1000 μm as compared with the emulsion polymerization, so that subsequent handling is easy. There are advantages such as being

The polymerization initiator used in the production method of the present invention is preferably soluble in the monomer composition, and such a polymerization initiator is 2,2'-azobisiso Butyronitrile, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobis-4
-Methoxy-2,4-dimethylvaleronitrile, other azo or diazo type polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, other peroxide type polymerization initiators and the like.

It is preferable to add a dispersion stabilizer to the dispersed phase. As the dispersion stabilizer, organic compounds such as carboxymethyl cellulose, polyacrylamide and polyvinyl alcohol, and poorly water-soluble inorganic fine particles such as calcium sulfate and tricalcium phosphate are used. Can be used. The amount of such a dispersion stabilizer added is 0.2 to 20 relative to the dispersed phase.
Weight% is preferable, and 0.5 to 5 weight% is more preferable. If the addition amount of the dispersion stabilizer is less than 0.2% by weight, it is difficult to obtain sufficient dispersion stability of the dispersed phase, and 20% by weight is obtained.
If the amount is larger, it becomes difficult to remove the dispersion stabilizer from the suspension-polymerized particles obtained from the polymerization reaction.

Further, it is possible to add a surface active agent such as sodium dodecyl sulfonate or sodium dodecylbenzene sulfonate as an auxiliary agent of the dispersion stabilizer. In addition, sodium chloride, sodium sulfate, neutral salts such as sodium dodecylsulfate may be added to the dispersed phase for the purpose of preventing emulsification, or for the purpose of preventing coalescence of the suspension-polymerized particles obtained by the polymerization reaction, glycerin, A thickener such as ethylene glycol may be added. In the production method of the present invention, other polymerization conditions such as polymerization temperature and polymerization time can be appropriately set.

The acrylic resin particles of the present invention thus obtained are thermoplastic, spherical particles having a particle size of 10 to 1000 μm, and have high impact resistance, handleability as a solid, and excellent flexibility. Therefore, it can be preferably used as a soft material application, a hot melt adhesive, a laminating resin, and a pressure-sensitive adhesive, in addition to an impact resistance modifier blended with another resin. Further, the resin composition of the present invention has such an acrylic resin particle blended with a hard resin such as a polymethylmethacrylate resin, a polyethylene terephthalate resin or a polycarbonate resin in an amount of 1 to 30 wt% to improve its impact resistance. It is a thing.

The present invention will be described below with reference to examples.
The present invention is not limited to this. In the examples, what is simply referred to as “part” means “part by weight”.

Example 1 A glass four-neck round bottom flask equipped with a stirrer was charged with 130 parts of water.
Add 0 parts and use polyvinyl alcohol 3 as a dispersion stabilizer.
Part, and stirring with a stirring blade at 300 rpm,
As a polymerization initiator, a monomer mixture comprising 330 parts of methyl methacrylate, 40 parts of methacrylic acid, 30 parts of butyl acrylate, and 30 parts of acrylonitrile, which is an outer layer, and a polymerization initiator
Charge 4 parts of 2'-azobisisobutyronitrile at once,
A suspension was created. While continuing stirring, 6
The temperature was raised to 8 ° C. and the reaction was kept constant for 4 hours. Then, it cooled to room temperature (about 25 degreeC). Then, the reaction product was subjected to solid-liquid separation, thoroughly washed with water, and then dried at 70 ° C. for 12 hours using a drier to obtain a methacrylic acid ester copolymer to be the outer layer.

Next, 275 parts of butyl acrylate and 82 parts of ethyl acrylate to form the inner layer of 40 parts of the above copolymer.
And acrylonitrile (43 parts) were mixed and stirred at room temperature for 12 hours to dissolve, thereby obtaining a solution of a monomer to be an inner layer in which a copolymer to be an outer layer was dissolved.

Further, 1300 parts of water was put into a glass four-necked round bottom flask equipped with a stirrer, 3 parts of polyvinyl alcohol was dissolved as a dispersion stabilizer, and the mixture was stirred with a stirring blade to give 300 parts.
While stirring at rpm, a monomer solution consisting of 440 parts of the above solution and 4 parts of N, N′-azobisisobutyronitrile as a polymerization initiator were added all at once to form a suspension.

The temperature of the inside of the reaction system was raised to 68 ° C. with continuous stirring, and the reaction was carried out by keeping the temperature constant for 4 hours. afterwards,
It was cooled to room temperature (about 25 ° C). Then, the reaction product is subjected to solid-liquid separation, thoroughly washed with water, and then dried at 70 ° C. in a dryer.
And dried for 12 hours to prepare multi-layered acrylic resin particles. The particles did not exhibit tackiness at room temperature and were particles having good handleability.

10 parts of this multilayer structure particle and molecular weight Mw = 1
90 parts of polymethylmethacrylate resin consisting of 0,000 was pelletized at 240 ° C. using a vented twin-screw extruder (PCM30 type manufactured by Ikegai). The obtained pellets were injection-molded at a molding temperature of 250 ° C. and a mold temperature of 80 ° C. using an injection molding machine (TOSHIBA MACHINE IS-100EN type), and predetermined sample pieces were prepared and evaluated.

The obtained sample piece had good handleability, flexibility and impact resistance. The results are shown in Table 1.

Example 2 The methacrylic acid of Example 1 was replaced with sodium styrenesulfonate 4
Acrylic resin particles were obtained in the same manner as in Example 1 except that the content was changed to 0 part. The evaluation results are shown in Table 1. Example 3 Acrylic resin particles were obtained in the same manner as in Example 1 except that the methyl methacrylate of Example 1 was changed to 40 parts of i-butyl methacrylate. The evaluation results are shown in Table 1.

Comparative Example 1 A glass four-neck round bottom flask equipped with a stirrer was charged with 130 parts of water.
Add 0 parts and use polyvinyl alcohol 3 as a dispersion stabilizer.
Part, and stirring with a stirring blade at 300 rpm,
30 parts of methyl methacrylate, 4 parts of methacrylic acid, 275 parts of butyl acrylate, 46 parts of acrylonitrile, 82 parts of ethyl acrylate and 4 parts of N, N'-azobisisobutyronitrile as a polymerization initiator Were added all at once to prepare a suspension.

The reaction system was heated to 68 ° C. under continuous stirring and kept constant for 4 hours for reaction. afterwards,
It was cooled to room temperature (about 25 ° C). Then, the reaction product is subjected to solid-liquid separation, thoroughly washed with water, and then dried at 70 ° C. in a dryer.
And dried for 12 hours to obtain acrylic resin particles having no multilayer structure. The number of parts of the monomer used in the resin particles of Comparative Example 1 is the same as the number of parts used in the inner layer and the outer layer of the resin particles of Example 1.

The acrylic resin particles were tacky at room temperature and were difficult to handle. Sample pieces were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 A glass four-necked round bottom flask equipped with a stirrer was charged with 130 parts of water.
Add 0 parts and use polyvinyl alcohol 3 as a dispersion stabilizer.
Part, and stirring with a stirring blade at 300 rpm,
As the outer layer, 330 parts of methyl methacrylate, 40 parts of methacrylic acid, 30 parts of butyl acrylate, and 30 parts of acrylonitrile, and a polymerization initiator of 2,
Charge 4 parts of 2'-azobisisobutyronitrile at once,
A suspension was created. While continuing stirring, 6
The temperature was raised to 8 ° C. and the reaction was kept constant for 4 hours. Then, it cooled to room temperature (about 25 degreeC). Then, the reaction product was subjected to solid-liquid separation, thoroughly washed with water, and then dried at 70 ° C. for 12 hours using a drier to obtain a methacrylic acid ester copolymer to be the outer layer.

Next, 40 parts of the above copolymer is used as an inner layer, 120 parts of methyl methacrylate, and 23 parts of ethyl acrylate.
By mixing with a monomer mixture liquid consisting of 2 parts and 42 parts of acrylonitrile and stirring at room temperature for 12 hours to dissolve, a monomer solution to be the inner layer was obtained by dissolving a resin to be the outer layer.

Further, 1300 parts of water was placed in a glass four-necked round bottom flask equipped with a stirrer, and 3 parts of polyvinyl alcohol was dissolved as a dispersion stabilizer.
While stirring at 0 rpm, a monomer solution consisting of 440 parts of the above solution and 4 parts of 2,2′-azobisisobutyronitrile as a polymerization initiator were added all at once to prepare a suspension.

The temperature of the reaction system was raised to 68 ° C. under continuous stirring and the reaction was carried out for 4 hours. afterwards,
It was cooled to room temperature (about 25 ° C). Then, the reaction product is subjected to solid-liquid separation, thoroughly washed with water, and then dried at 70 ° C. in a dryer.
And dried for 12 hours to prepare multi-layered acrylic resin particles.

The resin particles do not exhibit tackiness at room temperature,
It was in the form of particles that were easy to handle. Sample pieces were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Evaluation method (1) As for the handling property, the state of the resin particles was visually confirmed and the state where the particles were blocked at room temperature was marked with X, and the state where they were not blocked was marked with ◯. (2) Flexibility is the flexural modulus ASTM D-790
Was measured and evaluated according to. (3) Impact resistance is against the number of 15 samples when a weight of 100 g is dropped from a height of 500 cm using a DuPont drop weight impact test on the prepared sheet-like sample piece, The number of cracks was measured. (4) The glass transition temperature was measured according to JIS K7121. For the sample piece used for evaluation, the outer layer copolymer was used as it was for the outer layer, and the outer layer portion of the resin particles of the multilayer structure was scraped off for the inner layer, leaving only the inner layer, and then measured.

[0052]

[Table 1]

[0053]

As described above, according to the present invention,
It has excellent handleability and flexibility at room temperature, and is used for soft materials, hot-melt adhesives, laminating resins, pressure-sensitive adhesives as well as impact modifiers that blend with other resins. Acrylic resin particles that can be obtained are obtained.

Continued front page    F term (reference) 4J002 BG042 BG052 BG061 BG062                       CF061 CG001 FB262 FD202                       GF00 GJ01 HA09                 4J011 JB09 JB14 JB25 PA69 PB40                       PC02 PC07                 4J026 AA43 AA45 AA47 AA50 AA53                       AA62 AA63 AC09 AC34 BA25                       BA27 BA29 BA32 BA34 BA41                       BB03 BB07 DA02 DA03 DA04                       DB03 DB09 DB12 DB15 DB28                       EA04 FA02 FA07 GA06

Claims (5)

[Claims] 1. A multilayer structure comprising an inner layer mainly composed of an acrylic acid ester copolymer having a glass transition temperature of 0 ° C. or lower and an outer layer mainly composed of a methacrylic acid ester copolymer having a glass transition temperature of 60 ° C. or higher. Acrylic resin particles. 2. The methacrylic acid ester copolymer of the outer layer comprises:
0.5% by weight or more of a hydrophilic monomer is copolymerized, and the acrylic ester copolymer of the inner layer is obtained by copolymerizing the hydrophilic monomer at a copolymerization rate lower than that of the outer layer. The acrylic resin particles according to claim 1. 3. The weight ratio of the inner layer to the outer layer is 50/50.
The acrylic resin particles according to claim 1 or 2, wherein the acrylic resin particles have a particle size of 95/5. 4. A polymer having a glass transition temperature of 60 ° C. or more to be an outer layer is obtained by polymerizing a monomer containing a methacrylic acid ester, and then the resin is converted into a monomer containing an acrylate ester to be an inner layer. The solution is dissolved into a solution, and this solution is subjected to suspension polymerization to obtain an inner layer mainly composed of an acrylate copolymer having a glass transition temperature of 0 ° C. or lower, and a glass transition temperature of 60 ° C.
A method for producing an acrylic resin particle having a multi-layered structure comprising an outer layer mainly containing the above-mentioned methacrylic acid ester copolymer. 5. A resin composition containing the acrylic resin particles according to any one of claims 1 to 3.