JP2002138116A - (meth)acrylate polymer mixture, method of producing the same and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a (meth)acrylate polymer mixture with least unreacted monomer residue, odorless and free from bleeding even when a phthalate plasticizer is used together. SOLUTION: This (meth)acrylate polymer mixture comprises a (meth)acrylate polymer containing 5 to 50 wt.% of repeating unit derived from a (meth)acrylate monomer having a boiling point of 130 deg.C or higher and an unreacted (meth) acrylate monomer in a concentration of 500 ppm or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a (meth) acrylate-based polymer mixture, and more particularly to a (meth) acrylate-based monomer unit having a boiling point of 130.degree. The present invention relates to a (meth) acrylate-based polymer mixture having a low residual concentration of (meth) acrylate monomer.

[0002]

2. Description of the Related Art Conventionally, soft vinyl chloride resin products have been widely used as synthetic leather, crown seal materials and the like.
However, in recent years, there has been a demand for a soft resin molded product that does not generate hydrogen chloride even when incinerated waste products, and a soft acrylic resin molded product using a (meth) acrylate polymer instead of a vinyl chloride polymer has been required. It has come to be used. However, (meth) acrylate polymers (mainly methyl methacrylate polymers) are not suitable for plasticizers because phthalate ester plasticizers, which are general-purpose plasticizers, are not compatible with methyl methacrylate polymers. There is a problem that occurs.

In order to prevent bleeding from occurring in a soft resin product using a (meth) acrylate polymer, a monomer (meth) acrylate having a long alkyl group such as methyl methacrylate and butyl methacrylate or propyl methacrylate has a long alkyl group. A method using a copolymer with a body is effective. However, butyl methacrylate,
Monomers such as propyl methacrylate have a boiling point of 130
It is difficult to remove these monomers remaining unreacted even after performing an operation such as distillation after the completion of the polymerization reaction because of the high temperature of not less than ° C. For this reason, (meth)
When an acrylate polymer is produced, it is often obtained as a mixture of a (meth) acrylate polymer and these unreacted monomers. If a large amount of such unreacted (meth) acrylate monomer remains in the soft resin molded product, the odor may impair the comfort of the synthetic leather of the wallpaper or chair, and the crown seal material may impair the taste of food and drink. Cause problems. Therefore, the appearance of a (meth) acrylate polymer which has little residual unreacted monomer and has no odor and which can be used even with a phthalate plasticizer is expected.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a (meth) acrylate polymer which contains little residual unreacted monomer, has no odor, and does not bleed even when a phthalate plasticizer is used. The purpose of the present invention is to provide a manufacturing method. The present inventors, under the above circumstances, as a result of intensive research to solve the above problems,
It has been found that the amount of unreacted monomers can be significantly reduced by adding a redox-based polymerization initiator to an aqueous polymer dispersion and heating it, and based on this finding, the present invention has been completed.

[0005]

Thus, according to the present invention, there is provided (1) a (meth) acrylate polymer having 5 to 50% by weight of a repeating unit derived from a (meth) acrylate monomer having a boiling point of 130 ° C. or more. (2) a (meth) acrylate having a boiling point of 130 ° C. or higher; (2) a (meth) acrylate-based polymer mixture comprising a polymer and an unreacted (meth) acrylate monomer having a concentration in the polymer of 500 ppm or less; A monomer mixture containing a monomer is subjected to a polymerization conversion of 99%.
(3) The method for producing a (meth) acrylate-based polymer mixture according to the above (1), which comprises a step of polymerizing until the above is achieved, and a step of further adding and reacting a redox polymerization initiator. A (meth) acrylate having at least a repeating unit derived from a (meth) acrylate monomer having a temperature of 130 ° C. or higher, and having an unreacted (meth) acrylate monomer concentration of 500 ppm to 0.5% by weight in the polymer. The method for producing the (meth) acrylate-based polymer mixture according to the above (1), wherein a redox polymerization initiator is added to the aqueous dispersion of the based polymer, and the mixture is heated to 40 to 90 ° C. to cause a reaction. And (4) a resin composition comprising 100 parts by weight of the (meth) acrylate-based polymer mixture described in (1) above and 50 to 200 parts by weight of a phthalate plasticizer. Becomes soft resin molded article, is provided. In a preferred embodiment of the present invention, (5) the (meth) acrylate-based polymer mixture according to (1), wherein the (meth) acrylate monomer having a boiling point of 130 ° C. or higher is butyl methacrylate; (6) After completion of the reaction in the presence of the redox polymerization catalyst, -85 to-
The method for producing a (meth) acrylate-based polymer mixture according to the above (2) or (3), further comprising a step of degassing the evaporator while spraying the evaporator into a reduced pressure of 95 kPa. Is done.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A (meth) acrylate-based polymer (meaning an acrylate-based polymer and / or a methacrylate-based polymer) used in the present invention comprises acrylic acid or / and / or methacrylic acid and C1-C12. A copolymer obtained from at least two kinds of monomers comprising an ester compound with an aliphatic alcohol, or a copolymer of 50% by weight or more of the ester compound and another monomer copolymerizable therewith. And a repeating unit derived from a (meth) acrylate monomer having a boiling point of 130 ° C. or more is 5 to 50.
%, Preferably at least 10 to 45% by weight, more preferably at least 15 to 40% by weight.

In a copolymer having a repeating unit derived from a (meth) acrylate monomer having a boiling point of 130 ° C. or higher in the above range, bleeding of the plasticizer hardly occurs particularly when a phthalate ester plasticizer is blended. Further, since the soft resin molded product is less likely to relieve stress, it is suitable for applications such as packing. If the content of the repeating unit derived from the monomer having the above boiling point is excessively small, bleeding of the plasticizer may easily occur in a soft molded product obtained by blending a phthalate plasticizer with the polymer of the present invention. On the contrary, if the amount is excessively large, the mechanical strength of the obtained soft molded article may decrease, which is not preferable. The preferred (meth) acrylate polymer of the present invention is a polymer having, as a main structural unit, a repeating unit derived from methyl methacrylate, which is the most readily available (meth) acrylate monomer.

The (meth) acrylate monomers having a boiling point of 130 ° C. or higher include n-propyl methacrylate (boiling point 141 ° C. under normal pressure), n-butyl methacrylate (164 ° C.) and isobutyl methacrylate (15 ° C.).
5 ° C.), sec-butyl methacrylate (147
° C), n-dodecyl methacrylate (145 ° C), stearyl methacrylate (205 ° C), cyclohexyl methacrylate (210 ° C), n-butyl acrylate (148 ° C), tetradecyl acrylate (1
38 ° C.), undecyl acrylate (138 ° C.), hexadecyl acrylate (170), cyclohexyl acrylate (182 ° C.), benzyl methacrylate (233) and the like.

The glass transition temperature of the (meth) acrylate polymer used in the present invention is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, and 80 ° C.
It is particularly preferable that the above is satisfied. If the glass transition temperature is too low, there is a possibility that solid agglomerated particles may be formed in the drying step in the production of the polymer. When the polymer particles have a core-shell structure, the glass transition temperature of the polymer constituting the shell may preferably be 60 ° C. or higher, in which case the glass transition temperature of the polymer constituting the core is −
It can be as low as 20 ° C.

The above copolymerizable monomers 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) acrylate And unsaturated carboxylic acid ester compounds containing a hydroxyl group or an alkoxy group.

The (meth) acrylate polymer used in the present invention, for example, when used in a plastisol, suppresses an increase in sol viscosity due to a plasticizer penetrating the polymer during storage. Therefore, it is preferable to contain a carboxyl group. Such carboxyl group content,
It is preferably 0.2 to 5% by weight of the polymer, and 0.5 to 5% by weight.
More preferably, it is 3% by weight. When the polymer is particles having a core-shell structure, at least the shell layer may contain a carboxyl group in the above range. Examples of the carboxyl group-containing monomer for copolymerization for containing a carboxyl group in the (meth) acrylate polymer include acrylic acid, methacrylic acid, ethylacrylic acid, crotonic acid,
Unsaturated monocarboxylic acids such as cinnamic acid; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid, citraconic acid, chloromaleic acid and anhydrides; monomethyl maleate, monoethyl maleate, monobutyl maleate, fumarate Monomethyl acid, monoethyl 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.

Further, the (meth) acrylate polymer used in the present invention is, for example, when used in a plastisol or the like, as another embodiment for suppressing an increase in viscosity during storage of the plastisol. 0.5 to 15% by weight
Is also preferably a crosslinked polymer obtained by copolymerizing Such polyfunctional monomers include glycidyl (meth) acrylate, methyl glycidyl itaconate, (meth)
Epoxy group or epoxy group precursor-containing monomers such as allyl glycidyl ether and vinylcyclohexene monoxide; allyl compounds such as diallyl phthalate, diallyl adipate and triallyl cyanurate; divinyl compounds such as ethylene glycol divinyl ether and divinyl benzene; ethylene Examples include polyfunctional acrylates such as glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and oligoethylene di (meth) acrylate. it can. The amount of the crosslinked polymer in the (meth) acrylate-based polymer can be measured as a tetrahydrofuran-insoluble component. The content of tetrahydrofuran-insoluble matter is preferably 10 to 90% by weight, and
More preferably, it is 0 to 70% by weight.

The method of polymerizing the (meth) acrylate polymer used in the present invention is not particularly limited as long as it is a method of polymerizing in an aqueous medium, and examples thereof include fine suspension polymerization, suspension polymerization, emulsion polymerization, Seed emulsion polymerization and the like. Although the polymerization temperature is not particularly limited, it is preferably 30 to 80 ° C. In fine suspension polymerization, a mixture of a monomer, water, an emulsifier, an oil-soluble polymerization initiator, and the like is homogenized with a homogenizer or the like, emulsified and dispersed into fine droplets, and then polymerized. This is a method for obtaining a polymer latex having a wide particle size distribution having a normal distribution of 5 to 2 μm. This is an advantageous polymerization method for plastisol, because a large particle size and a low viscosity sol can be obtained. In order to produce a polymer having a core shell structure, at the time when the polymerization of the homogenized droplets serving as the core layer is completed, the monomers forming the shell layer may be added all at once, continuously or intermittently, and the polymerization may be continued. . Suspension polymerization consists of monomer, water, dispersant,
A method of obtaining a polymer slurry having a wide particle size distribution having an average particle size of about 20 μm to 3 mm by mixing a mixture such as an oil-soluble polymerization initiator with a stirrer in a reactor and polymerizing while separating and scattering oil droplets. is there. Emulsion polymerization uses an anionic or nonionic surfactant as an emulsifier, a water-soluble peroxide as a polymerization initiator, and promotes polymerization in a surfactant micelle layer containing a monomer, and has an average particle size of 0.05. This is a method for obtaining a polymer latex having a sharp particle size distribution of about 0.5 μm. Seeding emulsion polymerization is a polymerization method in which a latex polymer particle obtained by emulsion polymerization in advance is used as a seed, and a monomer is coated on the seed to enlarge the seed, and the emulsifier amount covers the entire surface area of the polymer particle. The polymerization is carried out continuously or intermittently so as to stay within 20 to 70% of the theoretical amount required for the coating, so that the formation of new microparticles 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 2 μm. As a polymerization method for obtaining the (meth) acrylate polymer used in the present invention, fine suspension polymerization and suspension polymerization are preferred from the viewpoint of polymerization productivity.

Examples of oil-soluble polymerization initiators used in fine suspension polymerization or suspension polymerization include, for example, diacyl peroxides such as 3,5,5-trimethylhexanoyl peroxide, lauroyl peroxide and benzoyl peroxide; methyl ethyl ketone peroxide Ketone peroxides such as oxides; hydroperoxides such as benzoyl hydroperoxide, cumene hydroperoxide and p-cymene hydroperoxide; peroxyesters such as t-butyl peroxypivalate; diisopropyl peroxydicarbonate; Peroxydicarbonates such as 2-ethylhexylperoxydicarbonate; organic peroxides such as sulfonyl peroxide such as acetylcyclohexylsulfonyl peroxide; 2,2-azobisisobutyronitrie , 2,2-azobis (2-methylbutyronitrile), 2,2-azobis (2,4-dimethylvaleronitrile), 2,2-azobis (4-methoxy-2,4-dimethylvaleronitrile), etc. And the like. Examples of the polymerization initiator used in the emulsion polymerization or the seed emulsion polymerization include a water-soluble initiator such as potassium persulfate, ammonium persulfate, and hydrogen peroxide; a water-soluble initiator or an organic peroxide, sodium hydrogen sulfite, ammonium sulfite, and ascorbin. Redox polymerization initiators combined with a reducing agent such as an acid; and water-soluble azo compounds such as 2,2-azobis (2-methylpropionamidine) dihydrochloride.

Examples of emulsifiers used in fine suspension polymerization, emulsion polymerization, etc. include alkylaryl sulfonates such as sodium dodecylbenzenesulfonate and potassium dodecylnaphthalenesulfonate; alkyl sulfates such as sodium lauryl sulfate and sodium tetradecyl sulfate. Sulfosuccinates such as sodium dioctyl sulfosuccinate and sodium dihexyl sulfosuccinate; fatty acid salts such as sodium laurate and potassium potassium semi-hardened tallow fatty acid; ethoxy sulfates such as sodium polyoxyethylene lauryl ether sulfate and sodium polyoxyethylene nonyl phenyl ether sulfate Salts; alkane sulfonates; alkyl ether phosphate sodium salts, and the like. The amount of the emulsifier is 0.05 to 100 parts by weight of the monomer.
It is preferably from 5 to 5 parts by weight, more preferably from 0.1 to 3 parts by weight. In the case of fine suspension polymerization, it is preferable to add an emulsifier in addition to the emulsifier, since the stability of the emulsified droplets increases. Examples of the emulsification aid include higher alcohols having 12 to 20 carbon atoms and fatty acids having the same carbon number. The amount of the emulsifying aid used is preferably 0.1 to 4 parts by weight, more preferably 0.5 to 2 parts by weight, per 100 parts by weight of the monomer. Examples of the dispersant used in suspension polymerization include polyvinyl alcohol, methoxycellulose, hydroxypropoxymethylcellulose, carboxymethylcellulose, and gelatin. The dispersant is preferably used in an amount of 0.005 to 0.8 part by weight based on 100 parts by weight of the monomer.
It is more preferable that the amount be from 0.01 to 0.5 part by weight.

In the present invention, the concentration of the (meth) acrylate monomer remaining in the (meth) acrylate polymer is set to 500 ppm or less, preferably 300 ppm or less, more preferably 100 ppm or less.

In the present invention, as a method for reducing the residual monomer from a polymer mixture in which the concentration of the (meth) acrylate monomer exceeds 500 ppm, a polymer particle is obtained by the above polymerization reaction. The method of reducing by removing the unreacted monomer continuously and the existing (meth) acrylate-based polymer particles having a high residual monomer concentration, including powder and aqueous polymer dispersion There is
There is a method of reducing residual monomers again.

In the method of removing unreacted monomers following the polymerization reaction, first, the polymerization reaction is carried out at a polymerization conversion of 99%.
Or more, preferably 99.2% or more, more preferably 9% or more.
Perform until 9.4% or more. If the polymerization conversion is less than 99%, it may be difficult to reduce the residual monomer concentration to 500 ppm or less. The polymerization addition rate is a method of sampling the reaction product and measuring from the solid content concentration,
By associating with the same method, there is a method of calculating from the integrated value of the amount of reaction heat removed from the polymerization reactor. After the polymerization conversion rate becomes 99% or more, a redox polymerization initiator is added to the polymerization reactor, preferably at a temperature of 40 to 90 ° C, more preferably 50 to 80 ° C, and preferably 3 to 12 ° C. The treatment reaction is performed for a time, more preferably for 4 to 8 hours. As the redox polymerization initiator, those described in the polymerization initiator used for the emulsion polymerization or the seed emulsion polymerization described above can be used. The addition amount of the redox polymerization initiator is preferably 0.05 to 3 parts by weight, more preferably 0.1 to 1 part by weight of a water-soluble initiator or an oil-soluble peroxide per 100 parts by weight of a polymer, and a reducing agent. Is preferably 0.02 to 1 part by weight, more preferably 0.05 to 0.5 part by weight.
If the amount of the redox initiator is excessively small, it may be difficult to reduce the residual monomer concentration to 500 ppm or less. Conversely, if the amount of the redox initiator is excessively large, the foaming characteristics in foam molding are hindered. It is not preferable because there is a possibility of doing so. The method of adding the redox polymerization initiator may be any of a batch type, a split type and a continuous type. Further, the redox polymerization initiator may be added as an emulsion using an emulsifier.

Next, the polymer aqueous dispersion is dried to obtain the (meth) acrylate polymer mixture of the present invention. The drying method is not limited, and if the aqueous polymer dispersion is in the form of a latex obtained by fine suspension polymerization, emulsion polymerization, seeding emulsion polymerization, etc., spray drying, or coagulation by salting out, etc. After separation, fluidized drying, flash drying, band drying, tray drying and the like can be used. In the case of employing a drying method in which polymer particles collide with each other in the air, such as spray drying and fluidized drying, it is preferable to use an inert gas such as nitrogen to prevent dust explosion. If the aqueous polymer dispersion is in a slurry state by suspension polymerization, drying is carried out in the same manner as in the coagulation method described above. Drying of the polymer is carried out until the residual water content is preferably 1% by weight or less, more preferably 0.5% by weight or less.

In the method of performing a residual monomer reduction operation on existing (meth) acrylate polymer particles having a large residual monomer concentration, the state of the existing polymer is taken out of the polymerization reactor. In the case of the above-mentioned latex or slurry, a redox polymerization initiator is added thereto, and when the state of the existing polymer is powdery, the slurry is reslurried in water and then the redox polymerization initiator is added. Is added. The method of adding the redox polymerization initiator may be any of a batch type, a split type and a continuous type. Further, the redox polymerization initiator may be added as an emulsion using an emulsifier. After that, the polymerization is carried out in the same manner as the method for removing unreacted monomers following the above polymerization. The polymer concentration of the aqueous polymer dispersion at the time of the residual monomer reduction treatment is preferably 20 to 50% by weight, more preferably 30 to 40% by weight.
It is.

The unreacted (meth) acrylate monomer having a boiling point of 130 ° C. or more is prepared by either of the above two methods.
A (meth) acrylate-based polymer mixture reduced to not more than 00 ppm can be obtained. When it is intended to obtain a polymer mixture in which the concentration of the (meth) acrylate monomer remaining in the polymer is reduced to 10 ppm or less, the above treatment is carried out by adding a redox polymerization initiator, Before the step of drying the coalescence, the aqueous dispersion of the polymer is
What is necessary is just to perform the process by the physical removal method which deaerates an evaporator while spraying into the evaporator which reduced pressure to -85-95 kPa in the state heated to 80 degreeC.

The (meth) acrylate polymer mixture of the present invention is blended with a plasticizer and used for producing a soft resin molded product. There is no limitation on the plasticizer, for example, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di- (2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, Phthalates such as diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate and myristyl benzyl phthalate; isophthalates such as di- (2-ethylhexyl) isophthalate and diisooctyl isophthalate Acid esters; tetrahydrophthalic acid esters such as di-2-ethylhexyltetrahydrophthalate;
Adipates such as (2-ethylhexyl) adipate, dibutoxyethyl adipate and diisononyl adipate; di-n-hexyl azelate, di- (2-
Azelaic acid esters such as ethylhexyl) azelate; sebacic esters such as di-n-butyl sebacate; maleic esters such as di-n-butyl maleate and di- (2-ethylhexyl) maleate; di-n-butyl Fumarate, di- (2-ethylhexyl)
Fumarate esters such as fumarate;

Trimellitate esters such as tri (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate and triisooctyl trimellitate; tetra- (2-ethylhexyl) pyromellitate;
Pyromellitic esters such as tetra-n-octyl pyromellitate; citrates such as tri-n-butyl citrate and acetyl tributyl citrate; dimethyl itaconate, diethyl itaconate, dibutyl itaconate, di- ( Itaconic esters such as 2-ethylhexyl) itaconate; oleic esters such as glyceryl monooleate and diethylene glycol monooleate; ricinoleic acid derivatives such as glyceryl monoricinolate and diethylene glycol monoricinolate; glycerin monostearate and diethylene glycol diester Stearic acid esters such as stearates;
Other fatty acid esters such as diethylene glycol diperargonate and pentaerythritol fatty acid ester;

Phosphates such as tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, diphenyldecyl phosphate and diphenyloctyl phosphate; diethylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di- (2-ethyl Hexoate), glycol derivatives such as tripropylene glycol dibenzoate and dibutyl methylene bisthioglycolate; glycerin derivatives such as glycerol monoacetate, glycerol triacetate and glycerol tributyrate; epoxidized soybean oil, epoxy butyl stearate, epoxy hexa Di-2-ethylhexyl hydrophthalate, diisodecyl epoxy hexahydrophthalate, epoxy tri Riseraido, epoxidized oleic acid octyl, epoxy derivatives such as epoxidized decyl oleate; adipic acid-based polyester, sebacic acid polyester, and polyester-based plasticizers such as phthalic acid-based polyester can be exemplified. Of these, phthalic esters are preferred. One of these plasticizers can be used alone, or two or more can be used in combination.

In the present invention, the amount of the plasticizer is based on 100 parts by weight of the (meth) acrylate polymer mixture.
Preferably 50 to 150 parts by weight, more preferably 70 to 150 parts by weight.
120 parts by weight. If the compounding amount of the plasticizer is excessively small, a soft resin molded article may not be formed,
Conversely, if the amount is excessively large, the mechanical properties of the molded article may deteriorate, which is not preferable.

In addition to the plasticizer, if necessary, a surfactant,
Pigments, fillers, foaming agents, antistatic agents, diluents and the like can be blended. Soft resin molding compositions of (meth) acrylate polymers include paste processing compositions (plastisols) for slush molding, coating molding, dipping molding, extrusion molding, injection molding, etc., compression molding, and calendar molding. And soft processing compositions in a narrow sense such as extrusion molding and injection molding. In the former, as the (meth) acrylate polymer, a polymer of latex particles obtained by the above-described fine suspension polymerization, emulsion polymerization or seed emulsion polymerization, and in the latter, a polymer of slurry particles obtained by suspension polymerization or a polymer of latex particles is used. Aggregates are mainly used. As for the form of the composition, the former is a paste (viscous paste), and the (meth) acrylate polymer is a copolymer with a carboxyl group-containing monomer or a polyfunctional monomer as described above. Accordingly, even if the plasticizer is stored for a long period of time, it is possible to suppress the permeation of the plasticizer into the polymer and obtain a plastisol having a stable viscosity. The latter is in the form of a wet powder, but the (meth) acrylate-based polymer produced by suspension polymerization has a shape close to a smooth sphere and has little retention of plasticizers and fine fillers. It tends to be uneven. Therefore, as the soft resin molding composition using the polymer of the present invention, a paste processing composition (plastisol) or a narrowly defined soft processing composition using latex particle aggregates is preferable.

The method for preparing a plastisol using the (meth) acrylate polymer mixture of the present invention is not particularly limited. Examples thereof include a crusher, a kneader, a planetary mixer, a horizontal paddle mixer, a butterfly mixer, a dissolver, and an intensive. Using a mixer, etc., (meta)
A plastisol can be prepared by sufficiently mixing and stirring the acrylate-based polymer, the plasticizer, and other optional additives.

The (meth) acrylate polymer mixture of the present invention has a (meth) acrylate having a boiling point of at least 130 ° C.
Since it contains 5 to 50% by weight of a repeating unit derived from an acrylate monomer, bleeding hardly occurs in a soft resin molded product obtained by blending a phthalate ester plasticizer which is an inexpensive and general-purpose plasticizer. Having. Further, since the concentration of the (meth) acrylate monomer remaining in the polymer mixture is 500 ppm or less, preferably 300 ppm or less, more preferably 100 ppm or less, particularly preferably 10 ppm or less, the molded article has no odor. have. Polymer residual monomer concentration is 100pp
m or less, the residual monomer concentration in a molded article obtained by heating the resin composition becomes 5 ppm or less. When the polymer residual monomer concentration is 10 ppm or less, the residual monomer concentration in the molded article becomes 10 ppb or less. The soft resin molded article of the (meth) acrylate polymer mixture of the present invention is:
General soft resin molded product applications, for example, synthetic leather,
Wallpapers, cushion floors, steel sheet coating materials, toys,
It can be used for crown seal material, vehicle outer plate seal material, conveyor belt, waterproof cloth, etc. In addition, since there is little residual monomer and no odor, it is used for food and drink such as crown sealing material, coating material in cans, and because there is almost no monomer that elutes even in contact with liquids, catheters, infusion bags,
It is suitable for medical equipment such as blood tubes.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. "Parts" and "%" in the following text are based on weight unless otherwise specified. The test method was as follows. (1) Average particle diameter The median diameter of a single particle diameter distribution measured by a laser diffraction scattering particle size distribution measuring apparatus (LA-300 manufactured by Horiba, Ltd.) was used as the average diameter using the latex after the reaction. (2) Total residual monomer concentration A sample is collected in a sealed container and heated at 140 ° C for 2 hours. The gas in the gas phase is collected with a gas tight syringe and measured by gas chromatography-mass spectrum analysis. The column temperature is measured by raising the temperature to 70 to 250 ° C.

(3) Initial viscosity of sol 100 parts of the dried and pulverized polymer and 80 parts of diisononyl phthalate were mixed at 23 ° C. for 10 minutes by a crusher, and then defoamed by a vacuum stirring deaerator at 667 Pa for 15 minutes. Thus, a plastisol for viscosity measurement was prepared. After defoaming, the sample is collected in a container, left at 23 ° C. for 1 hour, and then subjected to a viscosity measuring machine BROOKFIEL at 23 ° C. in an environment with a relative humidity of 60%.
D viscometer M type, and rotor No. 6r using 4
The value measured in pm was defined as the sol initial viscosity. (4) Sol viscosity storage stability index Close the container of the plastisol whose initial viscosity was measured and close it.
After storage at 2 ° C for 2 weeks, the viscosity is measured in the same manner as the initial viscosity in an environment of 23 ° C and a relative humidity of 60%. The value obtained by dividing the viscosity measurement value after two weeks by the initial measurement value is defined as the sol viscosity storage stability index. In practice, it is preferably 3.0 or less, and 1.5
The following is more preferred.

(5) Tensile strength The plastisol prepared in the above (3) is applied on a glass plate having a thickness of 2 mm to a thickness of 0.5 mm using a doctor knife and heated in a hot-air circulation oven at 180 ° C. for 10 minutes. Thus, a soft sheet was produced. Using the same sheet, JIS
The tensile strength at 23 ° C. was measured by a method according to K 6723. (6) Bleeding property of plasticizer The plastisol prepared in the above (3) was applied on a glass plate having a thickness of 2 mm to a thickness of 1.0 mm using a doctor knife, and heated in a hot air circulating oven at 180 ° C. for 15 minutes. To produce a soft sheet. After leaving this sheet in an environment of 23 ° C. and a relative humidity of 60% for 14 days, the bleeding property of the sheet was evaluated by visually inspecting the plasticizer oozing out on the sheet surface.

Example 1 In a tenless vessel equipped with a stirrer, 60 parts of methyl methacrylate, 30 parts of n-butyl methacrylate, 1 part of sodium dodecylbenzenesulfonate as an emulsifier, 1 part of a higher alcohol having 16 carbon atoms as an emulsifier, polymerization 0.3 parts of benzoyl peroxide and 2 parts of distilled water as an initiator
After stirring and mixing at room temperature for 30 minutes, a homogenizer was homogenized under high shear to prepare a fine suspension having an oil droplet diameter of 0.1 to 4 μm. Transferred to container. Polymerization was carried out under stirring at a temperature of 65 ° C. for 3 hours. After confirming a polymerization conversion of 95% or more based on the solid content of a small amount of the reaction solution, 6 parts of methyl methacrylate, 2 parts of styrene, An emulsion obtained by mixing 2 parts, 0.2 parts of sodium dodecylbenzenesulfonate and 20 parts of distilled water was added all at once, and the mixture was further polymerized for 3 hours. Total polymerization conversion is 9
9.2%.

Next, 0.1 part of ammonium persulfate, 0.002 part of ferrous sulfate, 0.005 part of ethylenediaminetetraacetic acid disodium salt and 0.00 part of sodium formaldehyde sulfoxylate were added to the polymerization vessel. 6
The reaction was continued at 5 ° C., and after 8 hours, the polymerization conversion was confirmed to be 100%. After cooling, a latex of a polymer having a core-shell structure was obtained. The latex was neutralized to pH 7.2 by adding a 5% aqueous solution of potassium hydroxide, dried with a spray drier at 170 ° C. in a nitrogen stream, and further turned into fine powder through a pulverizer sealed with nitrogen. Table 1 shows the test results of the obtained polymer.

Examples 2 to 3 and Comparative Examples 1 to 4 The same procedures as in Example 1 were carried out except that the polymerization recipe and the operation for removing residual monomers shown in Table 1 were employed. However, in Comparative Example 1, the residual monomer removal operation performed by adding the redox polymerization initiator was not performed. Table 1 shows the test results of the obtained polymer.

[0035]

[Table 1]

As shown in Table 1, a monomer mixture containing butyl methacrylate (160 ° C.) or butyl acrylate (148 ° C.) having a boiling point of 130 ° C. or more was polymerized to a polymerization conversion rate of 99% or more. By adding a polymerization initiator and performing heat treatment, butyl methacrylate or butyl acrylate is contained in an amount of 5 to 50% by weight, and unreacted (meth) acrylate monomer is 500 p.
pm or lower (meth) acrylate polymer mixture was obtained (Examples 1 to 3). Plasticizer bleed did not occur in the soft resin molded product obtained from the polymer mixture and the phthalate ester plasticizer. If the redox polymerization initiator addition treatment was not performed after performing the same polymerization reaction as in Example 1, the residual monomer concentration was 4100 ppm (Comparative Example 1). In the operation of removing the residual monomer, a large amount of unreacted monomer remained even when treated by adding a water-soluble initiator or an organic peroxide instead of the redox polymerization initiator (Comparative Examples 2 and 3). In the case of a polymer using methyl methacrylate (101 ° C.) and ethyl methacrylate (118 ° C.) having a boiling point of less than 130 ° C., the residual monomer concentration could be sufficiently reduced by the redox polymerization initiator treatment after the polymerization. The sheet molded using the acid ester plasticizer caused plasticizer bleed (Comparative Example 4).

Example 4 The (meth) acrylate monomer concentration obtained in Comparative Example 1 was 4900 ppm (the polymer obtained by spray-drying the
(00 ppm) of a polymer aqueous dispersion in a stainless steel container equipped with a stirrer, and ammonium persulfate 0.1 part, ferrous sulfate 0.002 part, ethylenediaminetetraacetic acid disodium salt 0.005 per 100 parts of polymer. And 0.2 parts of sodium formaldehyde sulfoxylate, and heat-treated at 80 ° C. for 10 hours.
The powder was dried with a spray drier in a nitrogen stream at 0 ° C., and further turned into a fine powder through a pulverizer sealed with nitrogen. The residual monomer of the obtained polymer was 20 ppm.

[0038]

Industrial Applicability According to the present invention, a (meth) acrylate-based polymer mixture which has little residual unreacted monomer, has no odor, and does not cause bleed even when a phthalate-based plasticizer is used, a method for producing the same, and a method for producing the same. A molded article is provided.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Satoshi Kobayashi 630 Ogibu, Takaoka-shi, Toyama F-term in Takaoka Plant of Zeon Corporation (reference) 4F071 AA33 AC10 AE04 AG28 AH03 AH05 AH07 BA09 BB03 BB04 BB05 BB06 BC17 4J002 BB041 BB051 EH146 FD026 GB01 GC00 GH00 GL00 GN00 4J011 AA05 AA10 AB02 AB15 BB02 BB09 KA04 KA28 KB22 KB29 4J100 AB02Q AB03Q AB04Q AE02Q AE04Q AE05Q AE10Q AG02Q AG04Q AJ01R AJ02R AJ03R AJ08R AJ09R AJ10R AK31R AK32R AL03P AL04P AL05P AL08Q AL09Q AL36R AL39R AL46R AM02Q AM08Q BA03R BA04Q BB01R BC43R CA04 CA05 FA03 FA20 FA27 FA41 GB02 JA28 JA51 JA57 JA67

Claims (4)

[Claims] 1. A (meth) acrylate polymer having a repeating point of 5 to 50% by weight derived from a (meth) acrylate monomer having a boiling point of 130 ° C. or more, and a concentration in the polymer of 500 ppm or less. A (meth) acrylate polymer mixture comprising an unreacted (meth) acrylate monomer. 2. A monomer mixture containing a (meth) acrylate monomer having a boiling point of 130 ° C. or higher is polymerized at a conversion rate of 9%.
The method for producing a (meth) acrylate-based polymer mixture according to claim 1, further comprising a step of polymerizing the mixture to 9% or more, and a step of further adding a redox polymerization initiator and further reacting the mixture. 3. It has at least a repeating unit derived from a (meth) acrylate monomer having a boiling point of 130 ° C. or higher,
A redox polymerization initiator is added to an aqueous dispersion of a (meth) acrylate polymer having an unreacted (meth) acrylate monomer concentration of 500 ppm to 0.5% by weight in the polymer, and a temperature of 40 to 90 ° C. The method for producing a (meth) acrylate-based polymer mixture according to claim 1, wherein the reaction is performed by heating the mixture. 4. A soft resin molded article comprising a resin composition having 100 parts by weight of the (meth) acrylate polymer mixture according to claim 1 and 50 to 200 parts by weight of a phthalate ester plasticizer.