JP4172601B2 - Monodisperse methacrylate resin particles and film formed by blending and forming the resin particles - Google Patents

Description

[0001]
[0002]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing methacrylate-based resin particles having excellent heat resistance in thermoplastic resin films such as polypropylene, polyethylene, polyester, polyamide, polyvinyl chloride, nylon, polystyrene, etc., and the resulting particles, and heat in which the particles are blended The present invention relates to a plastic resin composition and a film obtained therefrom. In particular, when the particles of the present invention are added to a polyolefin-based film, there is little variation in the effect of modifying slip properties and blocking resistance, and excellent transparency, slip properties and blocking resistance are exhibited. A film that does not cause defects is obtained.
[0003]
[Prior art]
Polypropylene, polyethylene, polyester, polyamide, polyvinyl chloride, nylon, polystyrene, and other films are widely used as various packaging materials because of their excellent transparency and mechanical properties. There is a problem of causing blocking, and the workability of packaging or the like is remarkably deteriorated, and the openability is extremely bad.
[0004]
Therefore, as a means for improving slipping and blocking resistance, a method of incorporating inorganic particles and forming fine protrusions on the film surface is generally carried out. As inorganic particles, silica, talc, etc. When blended with a polyolefin-based film, the transparency is remarkably reduced, and when the films are rubbed with each other, the surface is scratched and the transparency is further lowered.
[0005]
In addition, inorganic particles tend to aggregate due to the influence of moisture and the like, and when a polyolefin film is produced while containing aggregated secondary particles, there is a problem that large protrusions are formed on the surface, resulting in poor printing and poor lamination. there were. Therefore, by using organic particles that are less susceptible to moisture and the like, and secondary particles are less likely to be generated, the disadvantages are eliminated. However, organic particles have a disadvantage that they are inferior in heat resistance compared to inorganic particles. there were.
[0006]
In the case of production of polyester, polyamide, polyvinyl chloride, nylon and polystyrene, especially polypropylene or polyethylene film, the molding temperature tends to be set higher to improve productivity, and the heat resistance of organic particles is insufficient. It was a problem.
[0007]
Conventionally, various studies have been made on the method for producing organic particles, and many patents have been filed. One of the polymerization methods for obtaining vinyl resin particles having a heat resistance of about 250 ° C. or higher is called suspension polymerization, and forms droplets of vinyl monomer under an appropriate dispersion stabilizer in water. And polymerizing using a suitable oil-soluble polymerization initiator.
[0008]
However, when suspension polymerization is carried out under normal stirring conditions, resin adheres to the reaction vessel wall, stirring blades, etc., and even if resin particles are generated, the particle size distribution also breaks and coalesces the droplets during polymerization. Most of them were dominated by the stochastic factors of agglomeration, and only particles with a very wide particle size distribution range were obtained. Therefore, it is possible to classify the resin particles and narrow the particle size distribution to some extent, but it is impossible to completely remove the aggregated particles and obtain only monodisperse particles, and the coefficient of variation of the particle size is In order to obtain particles having a uniform particle size of 50 or less, it is necessary to perform sufficient classification, which causes a problem in the manufacturing process. In addition, since the establishment factor is large, the difference in the particle size distribution state and the average particle size due to the difference in the polymerization lots is large, and there is a problem that the effect of modifying the slip property and blocking resistance after film formation is large.
[0009]
As another method for producing particles having a uniform particle size distribution, there is a method disclosed in Japanese Patent Application Laid-Open No. 54-126288 or Japanese Patent Application Laid-Open No. 61-215604 relating to production of methacrylate particles called suspension seed polymerization. These methods can obtain resin particles having a uniform particle size and a coefficient of variation of 30 or less by absorbing the swelling aid into the seed particles and then polymerizing by absorbing the monomer component. Due to suspension seed polymerization method, heat resistance is insufficient. Therefore, there is a problem that the resin particles are thermally decomposed due to heat applied during film production, and the resin particles are thermally fused due to insufficient heat resistance, forming large protrusions on the film surface, and causing a printing defect or a lamination defect. .
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned drawbacks, the present inventors do not generate agglomerated particles, are excellent in monodispersity, have little variation in the particle size distribution state due to different polymerization lots, and have uniform particle sizes and particle fluctuations. The present invention has found a resin particle having a coefficient of 1-30, heat resistance during film molding, and less variation due to different polymerization lots in the effect of modifying slip properties and blocking resistance after film molding, and a method for producing the same. Has been completed.
[0011]
That is, the present invention contains 0.001 to 1 part by weight of a phenolic antioxidant, preferably 0.05 to 0.5 part by weight, and an average particle diameter of 0.1 to 1000 μm, based on 100 parts by weight of the methacrylate resin particles. A monodisperse methacrylate resin particle having a coefficient of variation of 1 to 30 (standard deviation / average particle size × 100) and a decomposition start temperature of 250 to 300 ° C., and (1) the particle is the phenolic antioxidant. are adsorbed and impregnated with a solution or dispersion, (2) the methacrylate main methacrylate-based resin is 1 or more can be polymerized with methyl methacrylate to 100 parts by weight per 100 parts by weight of methacrylate two constituting the resin particles It is a copolymer with a monomer having a hydroxyl group having a heavy bond, or the methacrylate resin particles contain PVA The present invention relates to monodisperse methacrylate resin particles.
[0012]
In the present invention, the adsorption / impregnation treatment means that the monodisperse methacrylate resin and the antioxidant are heated in an aqueous medium or a solvent, if necessary, and sufficiently stirred and mixed. Even if the treated resin particles are washed once or several times with a solvent, there is virtually no change in the thermal decomposition starting temperature, and when filtered through a sieve, a monodisperse methacrylate resin and an antioxidant are used. This is the process that makes separation impossible.
[0013]
An antioxidant can be mixed with the monodisperse methacrylate resin-containing suspension obtained by suspension seed polymerization or the like. It is also possible to separate the resin particles from the suspension, dissolve the particles in an aqueous medium or solvent, and stir and mix with the antioxidant. As the solvent, those which dissolve or disperse the antioxidant are preferable, and toluene, acetone, hexane, methanol and the like are used.
[0014]
The monodisperse methacrylate-based resin in the present invention is one kind of polymerizable monomer radically polymerizable with methyl methacrylate (MMA) and MMA such as ethylene glycol dimethacrylate and 1,6-hexylenediol diacrylate, or the like. Two or more kinds of crosslinkable copolymer resins. The constitutional ratio of MMA and polymerizable monomer is not particularly limited, but generally the weight ratio of MMA (A) and polymerizable monomer (B) is (A) / (B) = 100/0 to 50/50. Is in range.
[0015]
As a method of introducing a hydroxyl group into a methacrylate resin, a method of copolymerizing MMA and a polymerizable monomer in the presence of polyvinyl alcohol (PVA), or a monomer having a hydroxyl group and having a copolymerization property with MMA, such as 2- There is a method of copolymerizing hydroxyethyl methacrylate or 2-hydroxyethyl acrylate with MMA. The ratio of the monomer containing a hydroxyl group is 0.1 to 10 parts by weight.
[0016]
Although the production method of the methacrylate resin is not particularly limited, a product obtained by suspension polymerization, preferably emulsion polymerization, more preferably suspension seed polymerization is excellent as a raw material of the present invention.
[0017]
The suspension seed polymerization of the present invention uses a monodisperse methacrylate-based resin particle as a seed particle without using a swelling aid, swells the seed particle with MMA to be polymerized, and absorbs a monomer such as MMA. The polymerization is carried out in the presence of PVA and a dispersion stabilizer. As a result, it has a uniform particle size compared with other polymerization methods, a particle size variation coefficient of 1 to 30, an average particle size of 0.1 to 1000 μm, preferably 0.5 to 20 μm, and a hydroxyl value of 5 or more and 200 or less. Dispersible methacrolein resin particles can be obtained more reliably. However, if the resin particles obtained by suspension seed polymerization are separated and dried, the decomposition start temperature is less than 250 ° C. As an example, 100 parts by weight of monodisperse methacrylate resin particles containing a hydroxyl group obtained by this method and 0.1 to 10 parts by weight of a water-soluble phenolic antioxidant having a high hydroxyl value are stirred in an aqueous dispersion. By the adsorption / impregnation treatment, it was possible to obtain monodisperse resin particles having excellent heat resistance at a decomposition start temperature of 250 to 300 ° C. and having no particle aggregation.
[0018]
When a conventional antioxidant is not used, thermal decomposition of the resin particles occurs due to heat applied during film production. Therefore, the antioxidant used in the present invention is preferably a water-soluble phenolic antioxidant having a high hydroxyl value and excellent thermal decomposition inhibiting effect. The hydroxyl value is preferably from 200 to 1,000. When the adsorption / impregnation treatment is performed with a water solvent, the water solubility is preferably 0.01 to 100 parts by weight with respect to 100 parts by weight of water at 20 ° C., specifically p-methoxyphenol, hydroquinone and the like. Raised.
[0019]
If an organic solvent such as toluene is used, an antioxidant, a compound having an antioxidant effect, such as the following phenolic compound and an ultraviolet absorber, which are generally used for polyolefins, are preferably used. The antioxidant used for this application is not limited to these. Examples include butylated hydroxytoluene, 4-hydroxymethyl-2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl-β- (4′-hydroxy- 3 ', 5'-di-tert-butylphenyl) propionate, tocopherol, 2,4, bis (octylthiomethyl) -6-methylphenol, 2,2'-methylenebis (4-methyl-6-tert-butylphenol) 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 4,4'-butylidenebis (6-t-butyl- m-cresol), 1,1-bis (2′-methyl-4′-hydroxy-5′-t-butylphenyl) butane, 4,4′-thiobis (6-t- Til-m-cresol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxyhydrocinnamide) ), 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid monoethyl ester calcium salt, hexamethylenebis (3,5-di-tert-butyl-4-hydroxyhydrocinnamate), triethylene glycol Bis-3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate, 2,2′-oxamidobis [ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] 2,2'-ethylidenebis (4,6-di-t-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t -Butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3 ', 5 '-Di-t-butyl-4'-hydroxyphenyl) propionate] methane, 2,2'-methylenebis [6- (1-methylcyclohexyl) -p-cresol], bis [3,3-bis (4'- Hydroxy-3'-t-butylphenyl) butanoic acid] glycol ester,
Bis [2- (1,1-dimethylethyl) -6-[[3- (1,1-dimethylethyl) -2-hydroxy-5-methylphenyl] methyl] -4-methyl 1,4-benzenedicarboxylate Phenyl] ester, N, N, -bis {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl} hydrazine, 1,3,5-tris (3 ', 5'-di-t -Butyl-4'-hydroxybenzyl) -s-triazine-2,4,6 (1H, 3H, 5H) trione, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6- Dimethylbenzyl) -1,3,5-triazine-2,4,6- (1H, 3H, 5H) trione, 2,2'-methylenebis (4-methyl-6-nonylphenol), 2,6-bis (2 -Hydroxy-3-nonyl-5-methyl Benzyl) -p-cresol, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, pt-butylphenyl salicylate, 2, 4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3) ', 5'-di-t-amylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,5-bis- [ 5'-tert-butylbenzoxazolyl- (2)] thiophene, bis (3,5-di-tert-butyl-4-hydroxybenzylphos Oxalic acid monoethyl ester) nickel salt, methyl salicylate, methyl salicylate, p-methoxyphenol, phenyl salicylate, phenyl salicylate, 2-ethoxy-5-t-butyl-2'-ethyloxalic acid-bis-anilide, 2 -Ethoxy-5-t-butyl-2'-ethyl-4'-t-butyloxalic acid-bis-anilide, 2- (2H-benzotriazol-2-yl) -4- (1,1,3 3-tetramethylbutyl) phenol, poly [(6-morpholino-s-triazine-2,4-diyl) [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2, 2,6,6-tetramethyl-4-piperidyl) imino]], 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol and the like.
[0020]
Therefore, polyethylene, polyester, polyamide, polyvinyl chloride, nylon, styrene, preferably a polypropylene homopolymer, or a copolymer composition of polypropylene and other olefins, which is obtained by blending the monodisperse metacrine resin particles of the present invention. The film exhibited excellent slip properties even after film formation, hardly deteriorated in transparency, and when the films were rubbed with each other, the surface was scratched and the transparency was not deteriorated. The monodisperse metacrete resin particles of the present invention are preferably used for biaxially stretched polypropylene, biaxially stretched polyester, and biaxially stretched polyamide.
[0021]
The film must slip during processing such as bag making and printing, and have good machinability. If the slip property is insufficient, the films may rub against each other and the surface may be scratched, or if severe, the film itself may cause paper jamming and the workability of packaging or the like may be significantly reduced. On the other hand, if the bag is too slippery at the stage of transport from bagmaker to dealer, display at dealer, sales, etc. May cause damage to the contents. When a film is produced by blending monodisperse methacrylate resin particles having a very wide particle size distribution range with a particle size variation coefficient of 50 or more, which is generally used, Due to the variation, the slip property is difficult to control. When a large amount of particles are added, the slip becomes excessive, and when it is decreased, the slip becomes insufficient.
[0022]
However, by blending the resin particles with an average particle size of 0.1 to 1000 μm, preferably 0.5 to 20 μm and a coefficient of variation of about 30 (standard deviation / average particle size × 100) or less of the present invention, Since a more uniform uneven state can be obtained, the slip property can be controlled, and a film having slip property at the time of bag making but not slip property at the time of transportation or display can be produced.
[0023]
In addition, when the resin particle groups having different average particle diameters of the present invention are mixed with a polyolefin resin or the like, extruded with a granulator, pelletized, and masterbatched, various kinds of resins can be obtained by simply mixing the masterbatch. Arbitrary irregularities suitable for film applications could be created.
[0024]
【Example】
EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method of the various physical properties and characteristics in an Example is as showing below.
(1) Thermogravimetric change differential thermothermal gravimetric simultaneous measurement device (Seiko Denshi Kogyo Co., Ltd .: TG / DTA220) was used to measure the decomposition start temperature at an air temperature increase rate of 10 ° C./min. The larger this value, the better the heat resistance.
(2) Coefficient of variation (standard deviation / average particle size × 100)
Using a photograph taken with a scanning electron microscope (Topcon Co., Ltd .: SX-40A), the particle size was measured, and the coefficient of variation was calculated. The smaller this value is, the more uniformly the particle size is distributed.
(3) Hydroxyl value: Measured according to JIS K 0070.
[0025]
[Example 1]
In a 1 liter reactor equipped with a stirrer, cooling condenser, nitrogen gas inlet tube and thermometer, 150 parts by weight of deionized water, 5 parts by weight of sodium dodecylbenzenesulfonate, 1.5 parts by weight of PVA and 1 part by weight of benzoyl peroxide Then, the inside of the reactor was purged with nitrogen, 96 parts by weight of methyl methacrylate and 4 parts by weight of ethylene glycol dimethacrylate were added to the reactor, emulsified by stirring, and oil droplets were finely dispersed. 50 parts by weight of polymethyl methacrylate seed particles having an average particle size of 2.0 μm and a coefficient of variation of 6 (solid content concentration of 50 mass%) were added to the dispersed oil droplets, and the dispersed oil droplets were absorbed by the seed particles while stirring. Thereafter, the reaction was started by heating the reactor to 50 ° C., and then the reactor was heated to 75 ° C. and kept for 4 hours to complete the polymerization, followed by cooling. To this monodispersed liquid, 1 part by weight of p-methoxyphenol was added and stirred for 1 hour to carry out adsorption / impregnation treatment.
[0026]
The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a hydroxyl value of 19, a number average particle size of 3.2 μm, and a coefficient of variation of 6. Moreover, when the thermogravimetric decrease of the spherical fine particles was measured, the decomposition start temperature was about 258 ° C.
[0027]
[Example 2]
Example 1 was repeated except that 1 part by weight of p-methoxyphenol was changed to 1 part by weight of hydroquinone. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a hydroxyl value of 19, a number average particle size of 3.2 μm, and a coefficient of variation of 6. Further, when the thermal weight reduction of the spherical fine particles was measured, the decomposition start temperature was about 257 ° C.
[0028]
[Example 3]
1.5 parts by weight of PVA was not added, and 96 parts by weight of methyl methacrylate and 4 parts by weight of ethylene glycol dimethacrylate were changed to 94 parts by weight of methyl methacrylate, 4 parts by weight of ethylene glycol dimethacrylate and 2 parts by weight of 2-hydroxyethyl methacrylate. Example 1 was repeated except that. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a hydroxyl value of 16, a number average particle diameter of 3.2 μm, and a coefficient of variation of 6. Further, when the thermal weight reduction of the spherical fine particles was measured, the decomposition start temperature was about 257 ° C.
[0029]
[Example 4]
Example 1 was repeated except that 96 parts by weight of methyl methacrylate and 4 parts by weight of ethylene glycol dimethacrylate were changed to 100 parts by weight of methyl methacrylate. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a hydroxyl value of 19, a number average particle size of 3.2 μm, and a coefficient of variation of 6. Moreover, when the thermogravimetric decrease of the spherical fine particles was measured, the decomposition start temperature was about 258 ° C.
[0030]
[Example 5]
Example 1 was repeated without adding 1 part by weight of p-methoxyphenol. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were pulverized in a mortar and powdered. After adding 100 parts by weight of acetone in which 1 part by weight of p-methoxyphenol was dissolved in this powder and stirring for 1 hour to perform adsorption / impregnation treatment, the resulting suspension was centrifuged to precipitate particles, Cross-linked polymethyl methacrylate particles were separated by decantation of exchange water, and washed and dried three times. Moreover, the obtained crosslinked polymethyl methacrylate particles had a hydroxyl value of 22. Moreover, when the thermogravimetric decrease was measured, the decomposition start temperature was about 263 degreeC.
[0031]
[Example 6]
Example 1 was repeated without adding 1 part by weight of p-methoxyphenol. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were pulverized in a mortar and powdered. After adding 100 parts of toluene in which 1 part of Irganox 1010 (manufactured by Ciba Geigy) was dissolved to this powder and stirring for 1 hour for adsorption / impregnation treatment, the resulting suspension was centrifuged to precipitate particles, Cross-linked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, washed with water and dried three times. The obtained crosslinked polymethyl methacrylate particles had a hydroxyl value of 22. Moreover, when the thermogravimetric reduction | decrease was measured, decomposition | disassembly start temperature was about 278 degreeC.
[0032]
[Comparative Example 1]
Example 1 was repeated without adding 1.5 parts by weight of PVA and without adding 1 part by weight of p-methoxyphenol. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a number average particle diameter of 3.2 μm. Moreover, when the thermogravimetric decrease of the spherical fine particles was measured, the decomposition start temperature was about 240 ° C.
[0033]
[Comparative Example 2]
Example 1 was repeated without adding 1.5 parts by weight of PVA. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a number average particle diameter of 3.2 μm. Moreover, when the thermogravimetric decrease of the spherical fine particles was measured, the decomposition start temperature was about 245 ° C.
[0034]
[Comparative Example 3]
Example 1 was repeated without adding 1 part by weight of p-methoxyphenol. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a number average particle diameter of 3.2 μm. Moreover, when the thermogravimetric decrease of the spherical fine particles was measured, the decomposition start temperature was about 240 ° C.
[0035]
[Specific application example 4]
Example 3 was repeated without adding 1 part by weight of p-methoxyphenol. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a number average particle diameter of 3.2 μm and a coefficient of variation of 6. Moreover, when the thermogravimetric decrease of the spherical fine particles was measured, the decomposition start temperature was about 240 ° C.
[0036]
[Comparative Example 5]
Example 4 was repeated without adding 1 part by weight of p-methoxyphenol. The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a number average particle diameter of 3.2 μm. Further, when the thermal weight reduction of the spherical fine particles was measured, the decomposition start temperature was about 238 ° C.
[0037]
[Comparative Example 6]
Example 1 was repeated except that 1 part by weight of p-methoxyphenol was changed to 1 part by weight of ADK STAB LA-36 (manufactured by Asahi Denka Kogyo). The obtained suspension was centrifuged to precipitate the particles, and the crosslinked polymethyl methacrylate particles were separated by decantation of ion-exchanged water, followed by washing with water and drying three times. The obtained crosslinked polymethyl methacrylate particles were spherical fine particles having a number average particle diameter of 3.2 μm. Moreover, when the thermogravimetric decrease of the spherical fine particles was measured, the decomposition start temperature was about 244 ° C.
[0038]
【The invention's effect】
The methacrylate resin particles produced according to the present invention are monodisperse particles having excellent heat resistance. For example, they are excellent in dispersibility when added to polypropylene resin, and improve slipping, transparency, and blocking properties. It is effective and has great industrial value. In addition, a film free from printing defects and lamination defects can be obtained.

Claims (9)

Containing 0.001 to 1 part by weight of a phenolic antioxidant with respect to 100 parts by weight of the methacrylate resin particles, an average particle diameter of 0.1 to 1000 μm, a coefficient of variation of 1 to 30 (standard deviation / average particle diameter × 100) and Monodisperse methacrylate resin particles having a decomposition initiation temperature of 250 to 300 ° C., and (1) the particles are adsorbed and impregnated with the phenolic antioxidant solution or dispersion, and (2) the methacrylate. system or main methacrylate resin constituting the resin particles is a copolymer of a monomer having a hydroxyl group having a double bond one or more of the polymerizable with 1 to 10 parts by weight of methyl methacrylate per 100 parts by weight of methacrylate or monodisperse methacrylate resin particles methacrylate resin particles you characterized by containing PVA,.   The monodispersity according to claim 1, wherein the methacrylate resin is a copolymer of 0.1 to 10% by weight of 2-hydroxyalkyl methacrylate or 2-hydroxyalkyl acrylate with respect to the alkyl methacrylate. Methacrylate resin particles.   The monodisperse methacrylate resin particles according to claim 1, wherein the monomer having one or more double bonds is ethylene glycol dimethacrylate or 1.6-hexanediol diacrylate. Phenolic antioxidant, p- methoxyphenol or monodisperse methacrylate resin particles of claim 1 wherein the hydroquinone. The monodisperse methacrylate resin particles according to claim 4 , wherein the phenolic antioxidant is tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane. Monodisperse methacrylate resin particles according to any one of claims 1 to 5, characterized in that the methacrylate-based resin was obtained in suspension seed polymerization. A polypropylene composition containing 0.1 to 3 parts by weight of the monodisperse methacrylate resin particles according to any one of claims 1 to 6 with respect to 100 parts by weight of a polypropylene homopolymer or a copolymer of polypropylene and other olefins. object. The monodisperse methacrylate-based resin particles 0.1 to 3 according to any one of claims 1 to 6 , based on 100 parts by weight of a polymer selected from the group consisting of polyethylene, polyester, polyamide, polyvinyl chloride, nylon and polystyrene. A polymer composition containing parts by weight. The unstretched or biaxially stretched film which formed the composition of Claim 7 or 8 into a film.