JP2001214022A - Acrylic resin plastisol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an acrylic resin plastisol suitable for obtaining a thin film, having a low viscosity and good casting ability without causing projection or bleeding on the surface of the molded product caused by undispersed polymer particles. SOLUTION: This acrylic resin plastisol is obtained by including (A) a methyl methacrylate-based polymer, (B) a viscosity depressant, (C) a trialkylpentanediol carboxylate and (D) a plasticizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic resin plastisol, and more particularly, to a thin sheet having less protrusions and bleeds due to undispersed polymer particles.
Acrylic resin plastisol with low viscosity and good castability.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resin plastisols have good moldability, and are widely used for flooring materials, wall materials, steel sheet coating materials, automobile undercoat materials, vehicle outer panel sealing materials, conveyor belts, waterproof fabrics, and the like. Have been. However, in recent years, plastisols that do not emit hydrochloric acid even when waste products are incinerated have been required, and acrylic resin plastisols that use methyl methacrylate-based polymers instead of vinyl chloride-based polymers as paste resins have become increasingly expensive. The price has come to be used beyond the obstacles. However, since the specific gravity of the vinyl chloride resin is 1.4 and that of the acrylic resin (methyl methacrylate polymer) is 1.2, when using an acrylic resin to obtain a plastisol having the same viscosity, a plasticizer must be used. About 15% by weight. Further, in the case of producing a thin sheet having a thickness of 100 μm or less, more plasticizer is required in order to obtain a castability capable of applying a thin plastisol. As described above, since a molded article of an acrylic resin plastisol requires the use of a large amount of a plasticizer, bleeding of the plasticizer tends to occur. Therefore, there is a demand for the development of a technique for reducing the viscosity of an acrylic resin plastisol to a level lower than that of a vinyl chloride resin plastisol so as not to cause bleed.

[0003] Methods for reducing the viscosity of plastisols include adding a viscosity reducing agent (surfactant), increasing the amount of plasticizer,
Partial replacement of the paste resin with a blended resin (coarse-grained resin), and addition of a diluent (an organic solvent that volatilizes when heated) are included. The addition of the viscosity reducing agent can be said to be an indispensable method since it is only necessary to select an additive which does not adversely affect the molded article. However, since the degree of viscosity reduction obtained by using a viscosity reducing agent is about 50% at the maximum, the problem is whether there is a good method for further lowering the viscosity. Increasing the amount of plasticizer is the simplest method because it does not require the search for new materials to be added.However, as described above, bleeding occurs in the molded product, There is a problem that strength is reduced. How to use blend resin together
Since the particle size of the blend resin is as coarse as several tens of μm as compared with the paste resin of several μm, there is a problem that projections and streaks are caused in applications such as thin sheet or steel plate coating, and transparency is reduced. Therefore, we would like to adopt a method of adding a diluent.However, when many diluents commonly used in vinyl chloride resin plastisols are added to acrylic resin plastisols, the sol viscosity increases significantly during storage, and It causes bleeding and decreased transparency, and also loosens the polymer particle aggregates into the plasticizer, hinders dispersion and makes it easy to produce asako and buttocks, making it difficult to find a suitable diluent. Was.

[0004]

SUMMARY OF THE INVENTION The present invention uses a methyl methacrylate-based polymer particle as a paste resin to obtain a thin sheet having a good plasticizer dispersibility, a low viscosity, a good castability and a low viscosity. The purpose of the present invention is to provide an acrylic resin plastisol that can be used.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a methyl methacrylate-based polymer has been combined with a viscosity reducing agent and a specific diluent. It has been found that the desired plastisol can be obtained by blending the compound, and the present invention has been completed based on this finding. That is, the present invention
An acrylic resin plastisol comprising (A) a methyl methacrylate polymer, (B) a viscosity reducing agent, (C) a trialkylpentanediol carboxylate, and (D) a plasticizer.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The methyl methacrylate polymer as the component (A) of the composition of the present invention is a homopolymer of methyl methacrylate or 50% by weight of methyl methacrylate.
A copolymer of the above and a copolymerizable monomer. The glass transition temperature of the methyl methacrylate polymer of the component (A) is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, and further preferably 80 ° C. or higher. When the glass transition temperature is less than 60 ° C,
There is a possibility that solid agglomerated particles may be formed in a spray drying process usually employed in the production of a polymer for a paste. When the copolymer particles have a core-shell structure, if the glass transition temperature of the polymer constituting the shell satisfies the condition of 60 ° C. or higher, the glass transition temperature of the polymer constituting the core is:
For example, the temperature may be as low as -20 ° C. Examples of the copolymerizable monomer include aromatic vinyl compounds such as styrene, vinyltoluene, and α-methylstyrene;
Vinyl cyanide compounds such as acrylonitrile, methacrylonitrile, and vinylidene cyanide; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl ether compounds such as ethyl vinyl ether, cetyl vinyl ether and hydroxybutyl vinyl ether; α-hydroxyethyl (meth) acrylate , 3-hydroxybutyl (meth) acrylate, butoxyethyl (meth)
Examples thereof include unsaturated carboxylic acid ester compounds containing a hydroxyl group or an alkoxy group such as acrylate.

[0007] The methyl methacrylate-based polymer as the component (A) is used in order to prevent the viscosity of a plastisol prepared using the same from increasing during storage, that is, to increase the viscosity stability over time. Functional monomer 0.5 ~
It is preferable that the polymer contains a crosslinked polymer as a comonomer with 15% by weight so that swelling due to a plasticizer is hardly caused. Such polyfunctional monomers include:
Epoxy group or epoxy group precursor-containing monomers such as glycidyl (meth) acrylate, glycidyl-p-vinylbenzoate, methyl glycidyl itaconate, allyl glycidyl ether, methallyl glycidyl ether, and vinylcyclohexene monoxide; diallyl phthalate, diallyl male Allyl compounds such as ethyl, diallyl adipate and triallyl cyanurate; divinyl compounds such as ethylene glycol divinyl ether and divinyl benzene; ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate , Trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) Rate, such a polyfunctional acrylate such as oligoethylene di (meth) acrylate. The amount of the crosslinked polymer in the methyl methacrylate polymer can be measured as an insoluble portion of tetrahydrofuran (hereinafter sometimes referred to as THF). T
The HF insoluble content is preferably from 10 to 90% by weight, and more preferably from 30 to 70% by weight.

The methyl methacrylate polymer of the component (A) is used in another embodiment for increasing the viscosity stability of the plastisol. Content is about 0.2
It is also preferred that the polymer is contained as a constituent monomer unit in an amount of about 5% by weight. Such carboxyl group-containing monomers include, for example, acrylic acid, methacrylic acid,
Unsaturated monocarboxylic acids such as ethylacrylic acid, crotonic acid and cinnamic acid; maleic acid, itaconic acid, fumaric acid,
Citraconic acid, unsaturated dicarboxylic acids such as chloromaleic acid and anhydrides thereof; monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monobutyl fumarate, mono-2-hydroxyethyl fumarate, Monoesters of unsaturated dicarboxylic acids such as monomethyl itaconate, monoethyl itaconate, and monobutyl itaconate, and derivatives thereof can be given.

The method for producing the methyl methacrylate polymer as the component (A) is not particularly limited.
It can be produced by seeding emulsion polymerization, fine suspension polymerization, seeding fine suspension polymerization, or the like. Although the polymerization temperature is not particularly limited, it is preferably 30 to 80 ° C. Emulsion polymerization is
Using water as a dispersion medium, an anionic or nonionic surfactant as an emulsifier, and a water-soluble peroxide as a polymerization initiator, polymerization is promoted in a surfactant micelle layer containing a monomer, and an average particle size of 0.1 is obtained. This is a method for obtaining a polymer latex having a sharp particle size distribution of about 0.5 to 0.5 μm. The seeding emulsion polymerization method is a method for obtaining a latex of particles having a larger particle size than the emulsion polymerization method. The polymer particles in the latex obtained by emulsion polymerization in advance are used as seeds, and the amount of the emulsifier is the theoretical amount necessary to cover the entire surface area of the polymer particles during the polymerization reaction in which the monomer is coated. The polymerization is carried out while being supplied so as to stay within 20 to 60% of that of the coating, so that the formation of new fine particles is prevented as much as possible, and the coating polymerization is carried out.
This is a method for obtaining a polymer latex having a particle size distribution having one or two sharp modes of about μm.

In the fine suspension polymerization method, water is used as a dispersion medium, and a mixture of a monomer, an emulsifier, an oil-soluble polymerization initiator, etc. is dispersed into fine droplets using a homogenizer or the like, followed by polymerization. This is a method for obtaining a polymer latex having an average particle size of about 1 μm and a wide particle size distribution. In the seeded fine suspension polymerization method, a polymer suspension obtained by the fine suspension polymerization method is used as seed particles to further coat and polymerize a monomer. Examples of the emulsifier used for emulsion polymerization and fine suspension polymerization include, for example, alkyl aryl sulfonates such as sodium dodecylbenzenesulfonate and potassium dodecylnaphthalenesulfonate; alkyl sulfates such as sodium lauryl sulfate and sodium tetradecyl sulfate; dioctyl sulfosuccinic acid Sulfosuccinates such as sodium and sodium dihexylsulfosuccinate; fatty acid salts such as sodium laurate and potassium semi-hardened tallow fatty acid; ethoxysulfate salts such as sodium polyoxyethylene lauryl ether sulfate and sodium polyoxyethylene nonylphenyl ether sulfate; Alkane sulfonates;
Alkyl ether phosphate sodium salt and the like can be mentioned. The amount of the emulsifier used is preferably 0.05 to 5 parts by weight based on 100 parts by weight of the monomer,
More preferably, it is 0.1 to 3 parts by weight.

Examples of the water-soluble polymerization initiator used in the emulsion polymerization include water-soluble peroxides such as potassium persulfate, ammonium persulfate and hydrogen peroxide; these initiators or cumene hydroperoxide and t-butyl hydroperoxide. Redox initiators in which reducing agents such as sodium bisulfite, ammonium sulfite, and ascorbic acid are combined with hydroperoxides such as oxides, and water-soluble azo compounds such as 2,2-azobis (2-methylpropionamidine) dihydrochloride And the like. Examples of the oil-soluble polymerization initiator used in fine suspension polymerization include, for example, 3, 5,
Diacyl peroxides such as 5-trimethylhexanoyl peroxide, lauroyl peroxide, benzoyl peroxide; ketone peroxides such as methyl ethyl ketone peroxide; benzoyl hydroperoxide;
Hydroperoxides such as cumene hydroperoxide and p-cymene hydroperoxide; peroxyesters such as t-butylperoxypivalate; peroxydienes such as diisopropylperoxydicarbonate and di-2-ethylhexylperoxydicarbonate Carbonates; organic peroxides such as sulfonyl peroxides such as acetylcyclohexylsulfonyl peroxide; redox initiators obtained by combining these organic peroxides with reducing agents such as Rongalit; 2,2-azobisisobutyronitrile; 2,2-azobis (2-methylbutyronitrile), 2,2-azobis (2,4-dimethylvaleronitrile), 2,2-azobis (4-methoxy-2,4
-Dimethylvaleronitrile) and the like.

A latex containing methyl methacrylate-based polymer particles produced by emulsion polymerization, fine suspension polymerization, or the like is spray-dried using an inert gas such as nitrogen, or is subjected to salting out, coagulation, dehydration, and banding. The polymer particles may be dried by drying or the like, and pulverized as necessary to obtain polymer particle powder. In the present invention, the weight average molecular weight of the methyl methacrylate-based polymer of the component (A) is determined by dissolving 0.50 g of the polymer in 100 ml of THF. Using a mixed gel column, gel permeation chromatography (GPC) is performed using THF as an eluent, and measurement is performed by referring to the retention time of standard polystyrene.

In the present invention, the methyl methacrylate-based polymer as the component (A) has an average single particle diameter of from 0.05 to 0.05.
5.0 μm, preferably 0.3 to 3.0 μm
Is more preferable. If it is smaller than 0.05 μm, the viscosity of the plastisol may increase, and
If it is larger than m, the polymer particles may settle during storage of the plastisol. The average single particle size is 0.05 to 5.
A thickness of 0 μm is preferable because it can be suspended in a plasticizer to form a low-viscosity plastisol, and the degree of freedom in practical formulation is increased. In the case of a paste resin, when the latex is dried after salting out and coagulation, and also when spray-drying is performed, polymer particles dispersed in sprayed latex droplets of 50 to 200 μm are aggregated by drying. ,Normal,
The polymer is aggregated to form a powder. Therefore, the plastisol is prepared with the aim of loosening and assembling the aggregate well in the plasticizer.

In the present invention, a viscosity reducing agent is used as the component (B). As the viscosity reducing agent, nonionic surfactants, anionic nonionic surfactants, phospholipids and the like can be used, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene octyl naphthyl ether and the like Polyoxyethylene alkyl allyl ether;
Polyoxyethylene fatty acid esters such as polyethylene glycol monolaurate, polyethylene glycol monostearate and polyoxyethylene monooleate; polyoxyethylene polyoxypropylene block copolymer; polyglycerin condensed ricinoleate, mannitol condensed ricinoleate, dipentaerythritol Polyoxyethylene esters of condensed hydroxy fatty acids such as condensed 12-hydroxystearate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan distearate, and polyoxyethylene sorbitan trilaurate; sorbitan monostearate Fatty acid esters such as sorbate, sorbitandiolate and sorbitan trilaurate; Sodium Ren lauryl ether phosphate, polyoxyethylene oleyl ether sodium phosphate, polyoxyethylene alkyl ether phosphates such as polyoxyethylene stearyl ether sodium phosphate; and phospholipids such as lecithin.
The amount of the viscosity reducing agent used in the present invention is 0.0 to 100 parts by weight of the methyl methacrylate-based polymer (A).
The amount is preferably from 5 to 3.0 parts by weight, more preferably from 0.1 to 1.0 part by weight. If the amount of the viscosity reducing agent is less than 0.05 part by weight, the viscosity reducing effect may be reduced during long-term storage, while if it is more than 3.0 parts by weight, the defoaming properties of the sol may be impaired or the molding may be difficult. It may reduce the mechanical strength of the object. Among the above-mentioned viscosity reducing agents, the condensed hydroxy fatty acid polyhydric alcohol ester is preferable because the viscosity reducing effect and the viscosity stabilizing effect with time are particularly large in a plastisol using a methyl methacrylate polymer as a paste resin. Here, as the condensed hydroxy fatty acid, a 9,10-position substituted hydroxyl group of stearic acid, 2-hydroxytetradecanoic acid, 2-hydroxyhexadecanoic acid,
Condensates such as 10-dihydroxydioctadecanoic acid, hydrogenated castor oil fatty acid, sabinic acid, iprolic acid, and yarapinolic acid can also be used. As polyhydric alcohols, pentaerythritol, glycerin, sucrose, glucose and the like can also be used. . As a method for producing a condensed hydroxy fatty acid polyhydric alcohol ester, a condensed hydroxy fatty acid and a polyhydric alcohol can be used without a catalyst or phosphoric acid, p
-A method in which water produced at a temperature of 100 to 300 ° C is removed from the system while reacting in the presence of a catalyst such as toluenesulfonic acid or sodium hydroxide is exemplified.

The plastisol of the present invention contains a trialkylpentanediol carboxylate as a diluent for the component (C). As long as the alkyl group has 1 to 8 carbon atoms, three alkyl groups are not necessarily the same. The carboxylic acid is preferably an acid having 1 to 8 carbon atoms, and may be a diester or a monoester. Typical examples of the component (C) include 2,3,4-trimethyl-1,3-pentanediol diisobutyrate, 2,3,4-trimethyl-1,
Examples thereof include 3-pentanediol diacetate and 2,3,4-trimethyl-1,3-pentanediol dimonoisobutyrate. In the present invention, when the trialkylpentanediol carboxylate is blended with the acrylic resin plastisol, the viscosity of the sol is greatly reduced in combination with the viscosity reducing agent of the component (B), and the castability is remarkably improved. The sol can be spread quickly and without break even in the production of the sol. It should be noted that the action of the trialkylpentanediol carboxylate in the acrylic resin plastisol has an unexpected effect of significantly improving the dispersion of the methyl methacrylate polymer particles in the plasticizer. In applications such as thin sheet and steel sheet coating, if the dispersion of the polymer particles in the plasticizer is insufficient, the aggregates of the polymer particles will protrude and become so-called impaired aesthetics. The effect is particularly effective for coating a coating having a thickness of 100 μm or less. Trialkylpentanediol carboxylate is used as a normal diluent in the process of heating and gelling the sol.
There is no danger that the molded product will be unnecessarily softened because most of it is volatilized. The amount of the component (C) used in the plastisol of the present invention depends on the amount of the methyl methacrylate-based polymer 100 of the component (A).
The amount is preferably 1 to 30 parts by weight, more preferably 3 to 15 parts by weight, per part by weight. If the amount of the viscosity reducing agent used is less than 1 part by weight, a remarkable viscosity reducing effect cannot be obtained, while if it is more than 30 parts by weight, a large amount of volatiles is involved in the heat molding step,
Also, the mechanical strength of the molded product may be reduced.

In the present invention, the plasticizer used as the component (D) is not particularly limited, and examples thereof include dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate,
Diheptyl phthalate, di- (2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl Phthalic acid derivatives such as phthalate; isophthalic acid derivatives such as di- (2-ethylhexyl) isophthalate and diisooctyl isophthalate; tetrahydrophthalic acid derivatives such as di-2-ethylhexyltetrahydrophthalate and diisodecyltetrahydrophthalate; di- (2 Adipic acid derivatives such as -ethylhexyl) adipate, dibutoxyethyl adipate, diisononyl adipate; di-n
Azelaic acid derivatives such as -hexyl azelate, di- (2-ethylhexyl) azelate and diisooctyl azelate; sebacic acid derivatives such as di-n-butyl sebacate and di- (2-ethylhexyl) sebacate; di-
maleic acid derivatives such as n-butyl maleate and di- (2-ethylhexyl) maleate; fumaric acid derivatives such as di-n-butyl fumarate and di- (2-ethylhexyl) fumarate; tri (2-ethylhexyl) trimellitate; Trimellitic acid derivatives such as tri-n-octyl trimellitate, triisooctyl trimellitate and triisodecyl trimellitate; pyromellites such as tetra- (2-ethylhexyl) pyromellitate and tetra-n-octyl pyromellitate Acid derivatives; tri-n-
Citric acid derivatives such as butyl citrate, acetyl tributyl citrate and acetyl tri- (2-ethylhexyl) citrate; itaconic acid derivatives such as dimethyl itaconate, diethyl itaconate, dibutyl itaconate and di- (2-ethylhexyl) itaconate; Oleic acid derivatives such as glyceryl monooleate and diethylene glycol monooleate; ricinoleic acid derivatives such as glyceryl monoricinoleate and diethylene glycol monoricinoleate; stearic acid derivatives such as glycerin monostearate and diethylene glycol distearate; diethylene glycol diperargonate; Other fatty acid derivatives such as pentaerythritol fatty acid ester; tri- (2-ethylhexyl) phosphate, tributoxyethyl Phosphate derivatives such as phosphate, triphenyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, diphenyldecyl phosphate, diphenyloctyl phosphate; diethylene glycol dibenzoate, dipropylene glycol dibenzoate, tripropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di- (2-ethyl butyrate), glycol derivatives such as triethylene glycol di- (2-ethylhexoate), tripropylene glycol dibenzoate, dibutyl methylene bisthioglycolate; glycerol monoacetate, glycerol triacetate, glycerol tributyrate Glycerin derivatives such as epoxidized soybean oil, epoxy butyl stearate, epoxy hexahydride Phthalate -2
-Epoxy derivatives such as ethylhexyl, epoxyisodiyldecyl hexahexahydrophthalate, epoxytriglyceride, epoxidized octyl oleate, epoxidized decyl oleate; polyester plasticizers such as adipic acid-based polyester, sebacic acid-based polyester, and phthalic acid-based polyester; Can be mentioned. Among them, butyl benzyl phthalate, benzyl phthalate such as octyl benzyl phthalate, tricresyl phosphate, phosphate such as diphenyldecyl phosphate, acetyl tributyl citrate, citrate such as tributyl citrate, A plasticizer such as a dibenzoate ester type such as dipropylene glycol dibenzoate, tripropylene glycol dibenzoate and diethylene glycol dibenzoate, an adipate ester type, a sebacate ester type and a polyester type can be suitably used. These plasticizers
One kind may be used alone, or two or more kinds may be used in combination. Further, a material in which a high molecular compound such as rubber or resin is dissolved in a plasticizer can also be used.

In the present invention, the compounding amount of the plasticizer is
(A) 60 to 150 parts by weight, preferably 70 to 12 parts by weight, based on 100 parts by weight of the methyl methacrylate-based polymer as the component.
0 parts by weight is more preferred. If the amount of the plasticizer is less than 60 parts by weight based on 100 parts by weight of the methyl methacrylate polymer, the plastisol may have insufficient castability. If the amount of the plasticizer exceeds 150 parts by weight based on 100 parts by weight of the methyl methacrylate polymer, the mechanical properties of the molded article may be degraded. Generally, if the viscosity of the plastisol is 10 Pa · s or less, many types of sol processing can be performed. Particularly, if the viscosity of the plastisol is 5 Pa · s or less, the range of application is further expanded, and most applications such as coating, casting, and dipping are performed. It can be used. For applications such as thin sheet and steel plate coating, especially for forming a thin film with a thickness of 100 μm or less, a high degree of castability is required, and 2-4 Pa · s
The following viscosities are required.

The plastisol of the present invention may contain pigments, fillers, foaming agents, antistatic agents and the like, if necessary. The method for preparing the acrylic resin plastisol of the present invention is not particularly limited. For example, using a crusher, a kneader, a planetary mixer, a horizontal paddle mixer, a butterfly mixer, a dissolver, an intensive mixer, etc., the component (A), ( It can be prepared by sufficiently mixing and stirring the components (B), (C) and (D).

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. (I) The methyl methacrylate polymer used in Examples and Comparative Examples was produced by the following method. "Production example of methyl methacrylate polymer (resin a)" 97 parts by weight of methyl methacrylate and 3 parts by weight of methacrylic acid in a stainless steel container, 1.0 part by weight of sodium dodecylbenzenesulfonate as an emulsifier, and 18 carbon atoms as a dispersant 1.5 parts by weight of alcohol, 0.3 parts by weight of benzoyl peroxide as a polymerization initiator and 150 parts by weight of deionized water were added, and the mixture was stirred and mixed at room temperature for 30 minutes, and then homogenized under high shear by a homomixer. And the liquid phase is transferred to a stainless steel polymerization vessel so that the droplet diameter of the oil phase is 0.1 to 4
Prepared as a fine suspension of μm. Then polymerization temperature 65
Polymerization was carried out under stirring at 5 ° C. for 5 hours. After confirming that the polymerization rate was 95% or more based on the solid content of the reaction solution sampled in a small amount, the reaction was terminated. A latex was obtained. The latex was dried by a spray drier in a nitrogen stream at 170 ° C., and was further made into a fine powder through a pulverizer sealed with nitrogen. The single average particle size of the polymer resin particles thus obtained is 1.4 μm.
m. The carboxyl group content is 1.2%, the methyl methacrylate monomer unit is 97.7%, the weight average molecular weight is 1,820,000, and the THF insoluble content is 1.3%.
Met.

"Example of preparing methyl methacrylate polymer (resin b)" Methyl methacrylate 9 as a monomer component
A polymerization reaction was carried out in the same manner as in the production example of the methyll methacrylate-based polymer (resin a) except that 5 parts by weight and 5 parts by weight of glycidyl methacrylate were used to obtain a latex without neutralization. The latex was dried by a spray drier in a nitrogen stream at 170 ° C., and was further made into a fine powder through a pulverizer sealed with nitrogen. The single average particle diameter of the polymer resin particles thus obtained was 1.5 μm. The THF insoluble content is 5
It was 3.5%.

(Ii) The characteristics of the methyl methacrylate polymer were measured by the following methods. (1) Weight average molecular weight A resin sample (500 mg) subjected to a vacuum drying treatment at 40 ° C. and a degree of vacuum of 665 Pa for 3 hours is added to 100 ml of tetrahydrofuran as a reagent, and dissolved at room temperature for 24 hours (the insoluble content is 2% by weight or less). After removal and ignoring, if necessary), the sample is subjected to GPC using a mixed gel column with THF as an eluent, and the measurement is performed by referring to the retention time of standard polystyrene. In addition, the THF insoluble content is removed and measured. (2) THF-insoluble content 500 mg of a resin sample which had been subjected to vacuum drying at 40 ° C. and a degree of vacuum of 665 Pa for 3 hours was added to 50 ml of tetrahydrofuran as a reagent, and dissolved at room temperature for 24 hours.
The mixture is centrifuged at 00 rpm for 10 minutes, filtered, dried at 60 ° C. for 24 hours, and weighed.

(3) Carboxyl group content Using the latex after polymerization, the content of the acid monomer component is measured by conductivity titration using a standard titration solution of potassium hydroxide and hydrochloric acid. The acrylic acid monomer is (a) a particle layer,
(B) Present in the serum (liquid plasma) layer. First, the number of moles of carboxyl groups present in the serum layer is determined by conductivity titration, and then the content of the serum layer is subtracted from the total amount of acid monomers used in the reaction to obtain the content of the particle layer, which is converted to the weight% of the carboxyl group content. . (4) Average particle diameter The average diameter is defined as the median diameter of a single particle diameter distribution measured using a latex after polymerization and using a laser diffraction scattering particle diameter distribution measuring device (LA-300 manufactured by Horiba, Ltd.). .

(Iii) Various physical properties of plastisols obtained in Examples and Comparative Examples were measured by the following methods. (1) Sol initial viscosity Each component (unit g) in the table of the examples was mixed at once with a crusher at room temperature for 10 minutes, and subsequently, with a vacuum stirring deaerator at a degree of vacuum of 665 Pa for 15 minutes. By defoaming, a plastisol for viscosity measurement is prepared. After the defoaming treatment, the sample is collected in a sealed container, left at 23 ° C. for 1 hour, and the value measured at 23 ° C. in an environment of 60% humidity is defined as the sol initial viscosity. The viscosity was measured using a Brookfield viscometer type M. 4 at 60 rpm. (2) Time-dependent index (AI) of 7-day storage sol viscosity The plastisol whose initial viscosity was measured was sealed in a glass container, stored at 40 ° C. for 7 days, and then stored at 23 ° C. and 60% humidity.
After one hour in the room, the viscosity is measured. The value of the ratio of the viscosity measurement value after 7 days to the initial measurement value is defined as the aging index of the sol viscosity (Aging Index). In practice, it is required to be 3.0 or less, and particularly preferably 1.5 or less. (3) Tensile strength The same plastisol prepared in (1) above has a thickness of 2 mm.
Is applied with a doctor knife to a thickness of 0.5 mm on a glass plate, and heat-treated in a hot air circulating oven at 180 ° C. for 10 minutes to produce a sheet. Using the same sheet, JIS
The tensile strength at 23 ° C. is measured by a method according to K 6723.

(4) Elongation Using the same sheet prepared in (3) above, JIS
The elongation at break is measured simultaneously with the measurement of tensile strength by a method according to K 6723. (5) Bleed The plastisol prepared in the above (1) was applied on a glass plate having a thickness of 2 mm to a thickness of 1.0 mm using a doctor knife, and heat-treated in a hot air circulating oven at 200 ° C. for 15 minutes to form a sheet. Make it. This sheet is heated at 23 ° C. and humidity 60
% For 2 weeks, the bleeding property of the sheet is evaluated by visually inspecting the plasticizer oozing out on the sheet surface.
The evaluation criteria are as follows. ：: No bleeding was observed. Δ: Slight bleeding is observed. ×: Remarkable bleeding is observed. (6) Bubbles (granular projections) and diluent volatility The plastisol prepared in the above (1) was applied on a stainless steel plate with a doctor knife to a thickness of 100 μm.
The sheet is heated in a hot air circulating oven at 0 ° C. for 120 seconds to produce a sheet. The evaluation criteria are as follows. ：: The heat-formed film is transparent and no minute bumps are observed. Δ: The heat-molded film is transparent and minute spots are 1 to several / c.
m ² can be seen. X: The heat-formed film is transparent and fine spots are 10 pieces / cm.
^Two or more are seen, or the molded film is translucent or opaque even when no irregularities occur. Further, by reducing the weight after applying the plastisol and the weight after preparing the sheet together with the stainless steel plate, the rate at which the diluent volatilizes is reduced, and the diluent volatility is determined.

Examples 1 to 8 and Comparative Examples 1 to 5 The plastisol was prepared by mixing the substances listed in the columns of the formulations in Tables 1 and 2 at the indicated ratios with a grinder, A performance test of the sheet was performed. Table 1 shows the evaluation results of the performance of the plastisol and the thermoformed sheet.
And Table 2.

[0026]

[Table 1]

Note * 1: 2-ethylhexylbenzyl phthalate * 2: diphenyldodecyl phosphate * 3: 2,2,4-trimethyl-1,3-pentanediol diisobutyrate * 4: 2,2,4-trimethyl- 1,3-pentanediol monoisobutyrate * 5: Normal malaffin (boiling point 219 to 247 ° C) * 6: Isoparaffin (boiling point 158 to 175 ° C) * 7: Mineral spirit * 8: Butyl cellosolve * 9: Polyglycerin condensed ricinolate * 10: Polyoxyethylene nonylphenyl ether * 11: Polyoxyethylene sorbitan monolaurate * 12: Sodium polyoxyethylene oleyl ether phosphate * 13: Polyethylene glycol monolaurate

[0028]

[Table 2]

Notes are the same as in Table 1.

In Examples 1 to 8 satisfying the requirements of the present invention,
The initial viscosity of the plastisol is low (Examples 1 to 3 and 8) to moderate (Examples 4 to 7), and none of the viscosity increases with time or is extremely small. Further, none of the molded sheets has bleeding and bumps, and both have a sufficient tensile strength and elongation. In particular, as a viscosity reducing agent, a viscosity reducing agent 1
Example 1 using (polyglycerin condensed ricinoleate)
Nos. 3 to 8 are characterized by a much lower initial viscosity than Examples 4 to 7 and a small viscosity index over time. In addition, from the weight measurement of the buttocks test sheet, diluents 1 and 2
It was confirmed that １００100% by weight was volatilized. In Comparative Examples 1 to 3 using normal paraffin, isoparaffin or mineral spirit as the diluent, the initial viscosity of the plastisol is low but the increase with time is large. As for the formed sheet, several pieces (comparative example 1) to more than ten pieces (comparative examples 2 and 3) were generated per 1 cm ² . When butyl cellosolve is used as a diluent, the properties of the molded sheet are good, but the viscosity of the plastisol is high in the initial stage, and the solidification after 7 days causes a large change with time (Comparative Example 4). Compared with Example 1, Comparative Example 5 in which the amount of the plasticizer was increased instead of the diluent by that amount has a problem that the initial viscosity of the sol is increased and bumps are generated on the sheet surface.

[0031]

The acrylic resin plastisol of the present invention comprises:
Since the polymer particles have good dispersibility in plasticizer, low viscosity and good castability, a molded article free of protrusions and bleed on the molded article surface due to undispersed polymer particles can be obtained.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshio Nagase 1-2-1, Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term in the ZEON Kasei Co., Ltd. Kawasaki Laboratory (reference) 4J002 BG061 CH022 CH052 ED036 ED066 EG046 EH047 EH048 EH098 EH148 EH156 EH158 EW176 FD028 FD202 FD206 FD207 FD312 FD316 HA02

Claims (1)

[Claims] (A) a methyl methacrylate polymer,
An acrylic resin plastisol comprising (B) a viscosity reducing agent, (C) a trialkylpentanediol carboxylate, and (D) a plasticizer.