JP2005146139A - Acrylic polymer powder, acrylic sol and molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic polymer powder capable of producing an acrylic sol superior in storage stability, the molded product made from which has excellent mechanical strength, flexibility and retention of plasticizer, and then generates no gaseous hydrogen chloride when burned unlike the molded product made of a polyvinyl chloride sol, and to provide the acrylic sol and the molded product. <P>SOLUTION: This acrylic polymer powder is produced by coagulating and drying an emulsion containing a polymer particle, the shell portion of which has a layer of cross-linked structure. The acrylic sol comprises the acrylic polymer powder. The molded product is produced from the acrylic sol. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an acrylic polymer powder suitable for an acrylic sol, an acrylic sol containing the acrylic polymer powder and a plasticizer, and a molded product obtained from the acrylic sol.

Currently, the plastisol composition widely used industrially is a vinyl chloride sol composition obtained by dispersing polyvinyl chloride (vinyl chloride) powder and a filler in a plasticizer. , Foaming agents, diluents, etc. are used in combination. The vinyl chloride sol composition is used for various purposes in many fields as a coating agent, an impregnating agent, a caulking agent and the like for automobiles, carpets, wallpaper, floors and the like.
On the other hand, the hydrogen chloride gas generated during the incineration of the vinyl chloride sol composition has the disadvantage that it significantly damages the incinerator. Furthermore, due to recent environmental problems, it not only causes acid rain, but also the global ozone. It is also a layer-causing substance, and the appearance of a plastisol composition that has no difficulty in replacing such a PVC sol composition is expected in each commercial field.

  In response to such demands, acrylic sol compositions have been proposed as plastisols that do not generate hydrogen chloride gas during combustion, and those using uniform composition acrylic polymer particles are well known (for example, see Patent Document 1). However, when a general-purpose plasticizer such as dioctyl phthalate is used, the solubility of the particles in the plasticizer is high, and the viscosity of the acrylic sol composition increases within a few minutes after mixing. Therefore, there is a problem that it cannot be used practically. In addition, in order to improve the storage stability of the acrylic sol composition, a method of copolymerizing a monomer component having low compatibility with a plasticizer in an acrylic polymer has been proposed. When such an acrylic sol is used However, the plastic film tends to bleed out on the surface of the resulting film. Thus, when acrylic polymer particles are used, the relationship between storage stability and plasticizer retention after film formation (bleed-out resistance) is contradictory, and this is satisfied with polymer particles having a uniform structure. It was impossible to do.

  Therefore, an acrylic sol composition using core-shell structured particles has been proposed (see, for example, Patent Document 2), in which an acrylic polymer containing an acid in a polymer skeleton is used. However, the acrylic polymers proposed here have low compatibility with plasticizers, and when plasticizers with low polarity such as phthalate ester plasticizers are used, the plasticization state becomes poor and good. A coating film cannot be obtained. In addition, a plastisol composition using core-shell structured particles has also been proposed (see, for example, Patent Document 3). Here, even though the core-shell structured particles are referred to, uniform structured particles are produced, and this is subsequently subjected to alkaline hydrolysis. By performing the decomposition treatment, the ester group on the very surface of the particle is converted into a carboxyl group. Therefore, the thickness of the shell portion is extremely thin, and is substantially only about 1% or less of the volume of the particles. Therefore, the improvement effect of the storage stability expected as the role of the shell portion is extremely low. In addition, the shell portion introduced by alkaline hydrolysis has a very high acid value, has extremely low compatibility with the plasticizer, and remarkably deteriorates the film formability. In addition, such a structured particle having a high acid value shell part is easy to have an aggregated structure in the plastisol composition, and as a result, the plastisol composition becomes highly viscous at a low shear rate and the workability is lowered. Become a trend.

  Other examples of plastisol compositions using core-shell structured particles have been proposed (see, for example, Patent Document 4 and Patent Document 5). Here, by using a core-shell polymer consisting essentially of a core part that is compatible with the plasticizer and a shell part that is not compatible with the plasticizer, the basic performance (low level storage stability) And low level plasticizer retention). However, extremely high performance (high level of storage stability, high level of plasticizer retention, high level of mechanical performance (tensile strength, tensile elongation, etc.), etc.) is required for commercialization. In that respect, the polymers proposed in Patent Document 4 and Patent Document 5 are not optimized in the balance of compatibility with the plasticizer, storage stability, plasticizer retention of the coating film In addition, both the flexibility of the coating film and the coating film are low, and are not suitable for industrial practical use.

In addition, a method for crosslinking the entire acrylic polymer particles has been proposed to improve the storage stability of the acrylic sol composition (see, for example, Patent Document 6). However, when the entire particle is crosslinked, mechanical properties such as tensile strength and tensile elongation are remarkably lowered, which is unsuitable for industrial practical use. As described above, various studies have been made to make the most basic properties of the plastisol composition, ie, storage stability, plasticizer retention and coating film flexibility. The current situation is that the industrial practical level has not been reached.
Japanese Patent Publication No. 55-16177 (Claims) JP-A-5-279539 (Claims and Examples (paragraph number 0060)) JP-A-6-322225 (Claims) JP-A-7-233299 (Claims) JP-A-8-295850 (Claims) JP-A-10-168268 (Claims)

  The object of the present invention is to provide excellent storage stability, and a molded product obtained therefrom is excellent in mechanical strength, flexibility and plasticizer retention. Further, unlike molded products obtained from vinyl chloride sol, hydrogen chloride is incinerated during incineration. An object of the present invention is to provide an acrylic polymer powder capable of providing an acrylic sol that does not generate gas, the acrylic sol, and a molded product thereof.

  As a result of intensive studies to achieve the above object, the present inventors have used an acrylic polymer powder composed of polymer particles having a shell portion having a layer having a crosslinked structure as a component of an acrylic sol. The present inventors have found that the above problems can be solved and have completed the present invention.

That is, the present invention
(1) An acrylic polymer powder obtained by coagulating and drying a latex containing acrylic polymer particles, wherein the acrylic polymer particles contain the preceding polymer (Ia), Multi-stage polymer particles (I) obtained by forming a post-stage polymer (Ib),
The first stage polymer (Ia) is 10 to 90% by mass of methyl methacrylate units and 90 to 10% by mass of other monofunctional monomer units copolymerizable with methyl methacrylate, A copolymer formed by two or more successive polymerization reactions having different monomer compositions from each other;
The post-stage polymer (Ib) is composed of 50 to 99.99% by mass of methyl methacrylate units, 49.99% by mass or less of other monofunctional monomer units copolymerizable with methyl methacrylate, and polyfunctional. A cross-linked polymer formed by a polymerization reaction of one step consisting of 0.01 to 10% by weight of a monomeric monomer unit or two or more consecutive monomer steps having different monomer compositions,
Acrylic polymer powder having a mass ratio of the former stage polymer (Ia) / the latter stage polymer (Ib) of 50/50 to 95/5,
(2) Acrylic polymer powder obtained by coagulating and drying a latex containing acrylic polymer particles, wherein the acrylic polymer particles contain the preceding polymer (II-a), The multistage polymer particles (II) obtained by forming the middle stage polymer (II-b) and further molding the latter stage polymer (II-c),
The pre-stage polymer (II-a) is 50-99.99 mass% of acrylic acid methyl ester units, 49.99 mass% or less of other monofunctional monomer units copolymerizable with acrylic acid methyl ester, and many It is a cross-linked polymer formed by a polymerization reaction consisting of 0.01 to 10% by mass of functional monomer units in one step or two or more consecutive monomer steps having different monomer compositions,
Middle stage polymer (II-b) is composed of 50 to 100% by mass of methyl methacrylate units and 50% by mass or less of other monofunctional monomer units copolymerizable with methyl acrylate, A polymer formed by two or more successive polymerization reactions with different monomer compositions;
The post-stage polymer (II-c) is composed of 50 to 99.99% by mass of methyl methacrylate units, 49.99% by mass or less of other monofunctional monomer units copolymerizable with methyl methacrylate, and polyfunctional. A cross-linked polymer formed by a polymerization reaction of one step consisting of 0.01 to 10% by weight of a monomeric monomer unit or two or more consecutive monomer steps having different monomer compositions,
Acrylic polymer in which the mass ratio of the pre-stage polymer (II-a) / middle-stage polymer (II-b) / post-stage polymer (II-c) is 10-30 / 30-85 / 5-50 Acrylic polymer powder that is particles (II),
(3) The acrylic polymer powder according to (1) or (2), wherein the coagulation drying is spray drying,
(4) The acrylic polymer powder according to any one of (1) to (3), wherein all polymerization is performed by an emulsion polymerization method,
(5) An acrylic sol containing the acrylic polymer powder and plasticizer according to any one of (1) to (4), and (6) a molded product obtained from the acrylic sol according to (5). ,
About.

  According to the present invention, an acrylic polymer powder excellent in storage stability is provided. Furthermore, the acrylic polymer powder provides an acrylic sol having excellent mechanical strength, flexibility and plasticizer retention, and does not generate hydrogen chloride gas upon incineration, and a molded product thereof.

  Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to the following descriptions.

  The acrylic polymer powder of the present invention is obtained by coagulating and drying a latex containing the multistage polymer particles (I) and / or (II). For the multistage polymer particles (I), It is obtained by forming the post-stage polymer (Ib) in the latex containing the pre-stage polymer (Ia).

  The pre-stage polymer (Ia) is formed by a one-stage polymerization reaction or polymerized in two or more successive stages having different monomer compositions in a latex containing polymer particles obtained thereby. A copolymer formed by performing a reaction, and a copolymer formed by a polymerization reaction in each stage (including a case where only one stage is included) included in the previous stage is all methyl methacrylate units. It contains 10 to 90% by mass and 90 to 10% by mass of other monofunctional monomer units copolymerizable with methacrylic acid methyl ester. The proportion of methyl methacrylate units is preferably 20 to 80% by mass, and more preferably 30 to 70% by mass. When the methyl methacrylate unit of the pre-stage polymer (Ia) is less than 10% by mass, an acrylic polymer powder obtained by coagulating and drying a latex containing the acrylic polymer particles of the present invention and a plasticizer are used. The strength of the film formed from the acrylic sol contained (hereinafter sometimes simply referred to as “acrylic sol”) is not preferred because the strength of the film is reduced. The properties and flexibility are unfavorable.

  The post-stage polymer (Ib) contains polymer particles formed in or obtained by a one-stage polymerization reaction in a latex containing the particles of the pre-stage polymer (Ia). A cross-linked polymer formed by performing two or more successive polymerization reactions with different monomer compositions in the latex, and polymerization at each stage included in the subsequent stage (including cases where it consists of only one stage) The cross-linked polymer formed by the reaction is composed of 50 to 99.99% by mass of methyl methacrylate units and 49.99% by mass or less of units composed of other monomers copolymerizable with methyl methacrylate. It contains 0.01 to 10% by mass of a functional monomer unit. The proportion of methyl methacrylate units in the post-stage polymer (Ib) is preferably 55 to 95% by mass, and more preferably 60 to 90% by mass. When the methyl methacrylate unit of the post-stage polymer (Ib) is less than 50% by mass, the storage stability of the resulting acrylic sol is unfavorable. The polyfunctional monomer unit copolymerizable with the methacrylic acid methyl ester of the post-stage polymer (Ib) is preferably 0.02 to 5% by mass, more preferably 0.05 to 2% by mass. If the polyfunctional monomer unit is less than 0.01% by mass, the effect of improving storage stability is hardly exhibited, which is not preferable. Moreover, when it exceeds 10 mass%, the intensity | strength of the film | membrane formed from an acrylic sol will fall and it is unpreferable.

  Examples of other monofunctional monomers copolymerizable with methacrylic acid methyl ester include ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid. Methacrylic acid esters other than methyl methacrylate such as cyclohexyl acid; Acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate; Methacrylic acid hydroxyalkyl esters such as 2-hydroxyethyl acid and hydroxypropyl methacrylate and α, β-unsaturated carboxylic acids such as methacrylic acid; aromatic vinyl compounds such as styrene, p-methylstyrene and o-methylstyrene; N - Examples include maleimide compounds such as propylmaleimide, N-cyclohexylmaleimide, and N-o-chlorophenylmaleimide; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; among others, adjustment of glass transition temperature (Tg) and metal In view of the improvement of the adhesion to methacrylic acid, methacrylic acid esters such as isobutyl methacrylate, hydroxyalkyl methacrylates such as 2-hydroxyethyl methacrylate, and α, β-unsaturated carboxylic acids such as methacrylic acid are preferable. These other monomers can be used alone or in combination of two or more, and can be appropriately selected according to the purpose and application.

  The weight average molecular weight (Mw) when producing the pre-stage polymer (Ia) of the multi-stage polymer particles (I) used in the present invention is appropriately selected according to the application, It is preferably in the range of 50,000 to 3,000,000, and more preferably in the range of 100,000 to 2,000,000. When the weight average molecular weight is 50,000 or more, the strength of the formed film is improved, and when it is 3,000,000 or less, the dissolution rate with the plasticizer is appropriate and the productivity is improved. The weight average molecular weight can be adjusted using a chain transfer agent such as mercaptans. Examples of the mercaptans include n-octyl mercaptan, n-dodecyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan and the like. Can be mentioned.

  Regarding the post-stage polymer (Ib), examples of the polyfunctional monomer include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, propylene glycol dimethacrylate, polyethylene glycol dimethacrylate, hexanediol di Methacrylate, trimethylolpropane trimethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, polyethylene glycol diacrylate, hexanediol diacrylate, trimethylolpropane triacrylate, divinylbenzene, diaryl phthalate, Diaryl malates, divinyl adipates, allies Examples include acrylates, aryl methacrylates, triaryl cyanurates, triaryl isocyanurates, etc. Among them, those having a molecular weight of 250 or more are preferable, and polyalkylene glycol dimethacrylate having an average molecular weight of 400 to 600 is more preferable. preferable.

  The mass ratio of the former stage polymer (Ia) / the latter stage polymer (Ib) in the multistage polymer particles (I) is in the range of 50/50 to 95/5, and 60/40 More preferably within the range of ~ 90/10. When the proportion of the post-stage polymer (Ib) is less than 5% by mass, the effect of improving the storage stability of the resulting acrylic sol is hardly exhibited, and when it exceeds 50% by mass, the strength of the film formed from the acrylic sol Is not preferable.

  The acrylic polymer powder of the present invention is obtained by coagulating and drying a latex containing the multistage polymer particles (I) and / or (II). For the multistage polymer particles (II), It is obtained by forming the middle stage polymer (II-b) in the latex containing the former stage polymer (II-a) and further forming the latter stage polymer (II-c).

  The pre-stage polymer (II-a) is formed by a one-stage polymerization reaction, or two or more successive polymerizations having different monomer compositions from each other in a latex containing polymer particles obtained thereby. A cross-linked polymer formed by performing a reaction, and a cross-linked polymer formed by a polymerization reaction in each stage (including a case where only one stage is included) included in the previous stage is all methyl acrylate 50 to 99.99% by mass of units, 49.99% by mass or less of other monofunctional monomer units copolymerizable with acrylic acid methyl ester, and 0.01 to 10% by mass of polyfunctional monomer units It is a waste. As for the monomer unit composition of each said copolymer, all are 60-99.95 mass% of acrylic acid methyl ester units, 39.95 mass% or less of these other monomer units, and a polyfunctional monomer unit It is preferably 0.05 to 5% by mass, 70 to 99.9% by mass of acrylic acid methyl ester units, 29.9% by mass or less of the other monomer units and 0.1% of polyfunctional monomer units. More preferably, it is -3 mass%. When the acrylic acid methyl ester unit is less than 50% by mass, the cold resistance of the film formed from the acrylic sol is lowered. Moreover, when the polyfunctional monomer unit is less than 0.01% by mass, the strength of the film formed from the acrylic sol is lowered, and when it exceeds 10% by mass, the cold resistance of the film is lowered.

  Examples of the acrylic acid methyl ester with respect to the pre-stage polymer (II-a) include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, etc. An alkyl acrylate ester having an alkyl group of 1 to 4 is preferred, and methyl acrylate, propyl acrylate and n-butyl acrylate are more preferred.

  Regarding the preceding polymer (II-a), other monomers copolymerizable with methyl acrylate include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-methacrylate. Methacrylic acid esters such as butyl, isobutyl methacrylate and cyclohexyl methacrylate; hydroxyalkyl esters of methacrylic acid such as 2-hydroxyethyl methacrylate and hydroxypropyl methacrylate; α, β such as acrylic acid, methacrylic acid, crotonic acid and itaconic acid -Unsaturated carboxylic acid; aromatic vinyl compounds such as styrene, p-methylstyrene, o-methylstyrene; maleimide compounds such as N-propylmaleimide, N-cyclohexylmaleimide, and N-o-chlorophenylmaleimide; acrylonitrile; In particular, since it is suitable for adjusting the glass transition temperature (Tg) and improving the adhesion to metal, methacrylic acid esters such as methyl methacrylate, methacrylic acid 2 Preferred are methacrylic acid hydroxyalkyl esters such as hydroxyethyl and α, β-unsaturated carboxylic acids such as methacrylic acid. These other monomers can be used alone or in combination of two or more, and can be appropriately selected according to the purpose and application.

  Regarding the pre-stage polymer (II-a), the polyfunctional monomer is exemplified as a polyfunctional monomer copolymerizable with methacrylic acid methyl ester used in the production of the post-stage polymer (Ib). Similar to those mentioned above.

  The middle-stage polymer (II-b) is formed by a one-stage polymerization reaction in the latex containing the particles of the previous-stage polymer (II-a) or has a monomer composition of each other in the latex. It is a (co) polymer formed by carrying out two or more different continuous polymerization reactions, and is formed by a polymerization reaction in each stage (including the case of comprising only one stage) included in the middle stage (co-polymer). ) Each polymer contains 50 to 100% by mass of methyl methacrylate units and 50% by mass or less of other monofunctional monomer units copolymerizable with methyl acrylate. The proportion of methyl methacrylate units in the middle stage polymer (II-b) is preferably 60 to 100% by mass, and more preferably 70 to 100% by mass. When the methyl methacrylate unit of the post-stage polymer (II-b) is less than 50% by mass, the storage stability of the resulting acrylic sol is undesirably lowered.

  Regarding the middle-stage polymer (II-b), other monofunctional monomers copolymerizable with the acrylic acid methyl ester are the same as those used for the production of the latter-stage polymer (Ib). The thing similar to what was illustrated as another monofunctional monomer which can superpose | polymerize is mentioned.

  The post-stage polymer (II-c) is formed by a one-stage polymerization reaction in the latex containing the particles of the intermediate-stage polymer (II-b) or has a monomer composition of each other in the latex. A cross-linked polymer formed by performing two or more different continuous polymerization reactions, and a cross-linked polymer formed by a polymerization reaction of each stage included in the subsequent stage (including a case where it consists of only one stage) , All are 50 to 99.99% by mass of methyl methacrylate units, 49.99% by mass or less of other monofunctional monomer units copolymerizable with methyl methacrylate and 0. It contains 01 to 10% by mass. The proportion of methyl methacrylate units in the post-stage polymer (II-c) is preferably 55 to 95% by mass, and more preferably 60 to 90% by mass. When the methyl methacrylate unit in the post-stage polymer (II-c) is less than 50% by mass, the storage stability of the resulting acrylic sol is undesirably lowered. The polyfunctional monomer unit copolymerizable with the methacrylic acid methyl ester of the post-stage polymer (II-c) is preferably 0.02 to 5 mass%, more preferably 0.05 to 2 mass%. If the polyfunctional monomer unit is less than 0.01% by mass, the effect of improving storage stability is hardly exhibited, which is not preferable. Moreover, when it exceeds 10 mass%, the intensity | strength of the film | membrane formed from an acrylic sol will fall and it is unpreferable.

  Regarding the post-stage polymer (II-c), other monomers copolymerizable with the methacrylic acid methyl ester are copolymerizable with the methacrylic acid methyl ester used in the production of the post-stage polymer (Ib). The thing similar to what was illustrated as another monofunctional monomer is mentioned.

  Regarding the post-stage polymer (II-c), the polyfunctional monomer is exemplified as a polyfunctional monomer copolymerizable with methacrylic acid methyl ester used in the production of the post-stage polymer (Ib). Similar to those mentioned above.

  The weight average molecular weight (Mw) when the intermediate polymer (II-b) of the multi-stage polymer particle (II) used in the present invention is produced alone is appropriately selected depending on the application. Is preferably in the range of 50,000 to 3,000,000, and more preferably in the range of 100,000 to 2,000,000. When the weight average molecular weight is 50,000 or more, the strength of the formed film is improved, and when it is 3,000,000 or less, the melting rate with the plasticizer is appropriate and the productivity is improved. The weight average molecular weight can be adjusted using the same chain transfer agent as described for the multistage polymer particles (I).

  The mass ratio of the pre-stage polymer (II-a) / medium-stage polymer (II-b) / post-stage polymer (II-c) in the multi-stage polymer particles (II) is 10-30 / 30- It is in the range of 85/5 to 50, and more preferably in the range of 20 to 30/50 to 80/5 to 40. When the proportion of the post-stage polymer (II-c) is less than 5% by mass, the storage stability of the resulting acrylic sol is reduced, and when it exceeds 50% by mass, the strength of the film formed from the acrylic sol is reduced. It is not preferable.

The average particle size of the multistage polymer particles (I) and / or (II) used in the present invention is not particularly limited, but is preferably in the range of 0.05 to 30 μm, preferably 0.1 to 2 μm. It is more preferable to be within the range. If the average particle size is 0.05 μm or more, the storage stability in the sol state is good, and if it is 30 μm or less, the sol state can be made uniform, the sol preparation time can be shortened, and the productivity is improved. It becomes easy to do.
In addition, not only the case of acrylic polymer particles but also the case of acrylic polymer powder, the average particle size in this specification means the arithmetic average particle size.

The multistage polymer particles (I) and / or (II) used in the present invention can be produced in a latex state by a known polymerization method such as an emulsion polymerization method or a seed polymerization method. It is preferable to produce it legally.
For example, the pre-stage polymer (Ia) is formed by a one-stage emulsion polymerization reaction, or two or more successive stages having different monomer compositions in a latex containing polymer particles obtained thereby. The post-stage polymer (Ib) is formed by a one-stage emulsion polymerization reaction in the latex containing the particles of the pre-stage polymer (Ia). Or a latex containing polymer particles obtained thereby can be formed by carrying out two or more successive emulsion polymerization reactions having different monomer compositions. Multistage polymer particles (II) can also be produced in the same manner as multistage polymer particles (I).

  Examples of the emulsifier that can be used in the emulsion polymerization include dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate and sodium dilauryl sulfosuccinate which are anionic emulsifiers, alkyl benzene sulfonates such as sodium dodecylbenzene sulfonate, sodium lauryl sulfate, Alkyl sulfates such as sodium dodecyl sulfate; polyoxyethylene alkyl ethers and polyoxyethylene nonylphenyl ethers that are nonionic emulsifiers; polyoxyethylene nonylphenyl such as polyoxyethylene nonylphenyl ether sodium sulfate that is a nonionic and anionic emulsifier Ether sulfate, polyoxyethylene alkyl ether sulfate such as sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene tridecyl Alkyl ether carboxylates such as ether ether acetate; alkyl phenoxy polyethylene glycol acrylate which is a reactive emulsifier, acidic phosphoric acid methacrylate ester, alkyl aryl phenoxy polyethylene glycol, sodium-ω-acryloyloxyalkyl (trialkyl) ammonium-para Toluenesulfonate, sodium-polystyrene phenyl ether sulfate, dimethylaminoethyl methacrylate quaternized product, sodium-sulfosuccinic acid alkyl alkenyl ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether sulfonate, alkylphenoxyethoxyethyl sulfonate, sodium-dialkyl Sulfosuccinate, alkyldiphenyl A One type or two or more types of terdisulfonate, nonylpropenylphenol ethylene oxide 10-mol adduct sulfate ester ammonium salt can be used. The average repeating number of oxyethylene units in the exemplified compounds of the nonionic emulsifier and the nonionic anionic emulsifier exemplified above is preferably 30 or less so that the foaming property of the emulsifier does not become extremely large. More preferably, it is more preferably 10 or less.

In the emulsion polymerization, any polymerization initiator such as a persulfate initiator such as potassium persulfate or ammonium persulfate, or a redox initiator such as persulfoxylate / organic peroxide or persulfate / sulfite is used. May be. If necessary, a known chain transfer agent may be used.
In emulsion polymerization, monomers, emulsifiers, polymerization initiators, chain transfer agents, etc. can be added by any known method such as batch addition, divided addition, continuous addition, etc., depending on the polymerization reaction at the target stage. it can.

The latex used in the present invention is a latex containing multistage polymer particles (I) or multistage polymer particles (II), or a latex containing multistage polymer particles (I) and multistage polymer particles (II). ) Containing latex in an arbitrary ratio.
Further, the latex used in the present invention may be a latex in which a plurality of, for example, two or three types of latex each containing acrylic polymer particles having different particle size distributions are mixed.

  The method for coagulating and drying the latex is not particularly limited. Specifically, for example, by a method of pulverizing the latex by a spray drying method, a method of coagulating an acrylic polymer by adding an acid or a salt to the latex, and drying the coagulated product to form a powder Acrylic polymer powder can be obtained. Among these coagulation drying methods, a spray drying method having an advantage of easily adjusting the average particle size, particle size distribution and shape (preferably spherical) of the acrylic polymer powder is preferable.

  This acrylic polymer powder is mainly used to prepare an acrylic sol by mixing with a plasticizer. The average particle size of the acrylic polymer powder of the present invention is preferably 5 to 100 μm, More preferably, it is in the range of 50 μm. When the average particle size is 5 μm or more, the acrylic polymer particles are difficult to be handled as a fine powder at the time of acrylic sol preparation, and handling is easy. In addition, the strength of the film is easily improved (the cracks are less likely to start and cracks are less likely to occur).

In addition, the acrylic sol of the present invention, when the porosity of the acrylic polymer powder is 70% or less, the absorption of the plasticizer into the acrylic polymer powder is suppressed, the fluidity is improved, the dilatancy, etc. This is preferable because it is less likely to occur and the molding processability is improved. Therefore, the porosity of the acrylic polymer powder of the present invention is preferably 70% or less, and more preferably 60% or less.
In the present invention, the porosity represents the ratio of the interparticle space volume to the constant volume (including interparticle space volume) of the acrylic polymer powder, and the pore volume of the powder is measured by mercury porosimetry. You can ask for it.

  In the present invention, the acrylic polymer powder is mixed with a plasticizer to form an acrylic sol. The acrylic polymer powder used at this time may be a blend of two or more acrylic polymer powders having different particle diameters.

The plasticizer that can be used in the acrylic sol of the present invention is not particularly limited. Phthalate plasticizers such as butoxyethyl phthalate, diphenyl octyl phosphate, tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trixylenyl phosphate, tri-2-ethylhexyl phosphate, 2- Ethylhexyl diphenyl phosphate, trisisopropyl phenyl phosphate, resorcinol bisdiphenyl phosphate Phosphate ester plasticizers such as sulfate, bisphenol A bisdiphenyl phosphate, bisphenol A biscresyl phosphate, adipate plasticizers such as di-2-hexyl adipate, and sebacic acid esters such as di2-ethylhexyl sebacate Plasticizers, azelaic acid ester plasticizers such as di-2-hexyl azelate, trimellitic acid ester plasticizers such as tri-2-ethylhexyl trimellitate, fumaric acid ester plasticizers such as dibutyl fumarate, acetyl Citric acid ester plasticizers such as tributyl acid, oleic acid ester plasticizers such as butyl oleate, and polyester plasticizers can be used.
These plasticizers are used alone or in combination of two or more. When it is required to impart flame retardancy to a molded product obtained from an acrylic sol, it is preferable to use a phosphate ester plasticizer.

  The mixing ratio of the acrylic polymer powder and the plasticizer is preferably 50 to 500 parts by mass, more preferably 50 to 200 parts by mass, per 100 parts by mass of the acrylic polymer powder.

  The acrylic sol of the present invention can further contain a filler. Examples of fillers that can be used include calcium carbide, baryta, clay, colloidal silica, mica powder, diatomaceous earth, kaolin, talc, bentonite, glass powder, aluminum oxide, aluminum hydroxide, antimony trioxide, titanium dioxide, Examples thereof include carbon black, metal soap, dye, and pigment. The filler content is preferably 50 to 500 parts by mass per 100 parts by mass of the acrylic polymer powder.

  In addition to the above, the acrylic sol of the present invention can be made into an organosol by adding a solvent such as a mineral turbine as a diluent. Furthermore, various additives can be contained depending on the purpose. Examples of such additives include adhesion promoters, leveling agents, tack prevention agents, mold release agents, antifoaming agents, foaming agents, surfactants, ultraviolet absorbers, lubricants, flame retardants, light stabilizers, and antiaging agents. , Antioxidants, fragrances and the like, and these can be used alone or in combination of two or more. In general, the content of these components is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the acrylic polymer powder.

The acrylic sol of the present invention can be prepared by mixing the acrylic polymer powder of the present invention, a plasticizer, and, if necessary, a filler and other additives.
Although there is no restriction | limiting in particular about solid content in the acrylic sol of this invention, From viewpoints, such as a fluidity | liquidity of an acrylic sol, it is preferable that it is about 20-80 mass% with respect to the whole acrylic sol.

  When making a foamed product using the acrylic sol of the present invention, it is generally possible to obtain a foamed product having excellent foamed state uniformity. As a method of making a foamed product using an acrylic sol, bubbles are mechanically mixed in the acrylic sol to form a bubble sol and gelled (mechanical foaming method). There are a method of gelling a microcapsule type foaming agent encapsulated in a microcapsule into an acrylic sol, a method of gelling a thermal decomposition type foaming agent that generates gas at high temperature into an acrylic sol, and whichever is used However, the method using a pyrolytic foaming agent is most preferable in achieving the above effect.

  When using a thermal decomposable foaming agent, prepare an accelerator containing the above acrylic polymer powder, plasticizer and thermal decomposable foaming agent, and foam it by heating to form a foamed molded product (foam). To do. Conventionally known thermal decomposition type foaming agents can be used as the thermal decomposition type foaming agent without any particular limitation. Specifically, for example, azodicarbonamide, 4,4′-oxybis (benzenesulfonylhydrazide) P-toluenesulfonyl hydrazide, azobisisobutyronitrile, azodiaminobenzene, azohexahydrobenzodinitrile, barium azodicarboxylate, N, N′-dinitrosopentamethylenetetramine, N, N′-dinitroso-N , N′-dimethylterephthalamide, t-butylaminonitrile, p-toluenesulfonylacetone hydrazone and the like, and organic pyrolysis foaming agents such as sodium bicarbonate and ammonium carbonate. . These may be used alone or in any combination of two or more. Among these thermally decomposable foaming agents, azodicarbonamide-based thermally decomposable foaming agents are preferable because they are easy to handle and generate a large amount of gas.

  The amount of the pyrolytic foaming agent added varies depending on the foaming ratio (specific gravity) of the target foam or foam layer, the use of the foam or laminate, the amount of gas generated by the foaming agent, etc. The amount is preferably 0.05 to 30 parts by mass and more preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the acrylic sol.

  Further, in the present invention, in producing a foam using the above-described pyrolytic foaming agent, a foaming aid is added in order to smoothly foam and obtain a foam having more uniform and fine bubbles. You may use together. As the foaming aid in that case, the foaming aid conventionally used for each pyrolyzable foaming agent can be used. For example, for azo foaming agents, sodium bicarbonate, hydrazine foaming agents, foaming aids such as carboxylic acid metal salts, carbonate metal salts such as calcium carbonate, metal oxides such as silica and alumina, and minerals such as talc. In addition, for example, for N, N′-dinitrosopentamethylenetetramine, foaming aids such as urea compounds and organic acids can be used.

  Processing methods using the acrylic sol of the present invention include dip coating, knife coating, roll coating, curtain flow coating, and other molding methods such as dip molding, cast molding, slash molding, and rotational molding, as well as immersion. Various processing methods such as brushing, spraying and electrostatic coating are possible.

  In order to form a gel, which is a molded product, using the acrylic sol of the present invention, it is necessary to maintain the acrylic sol at an appropriate gel formation temperature and processing time. The gel formation temperature is preferably in the range of 70 to 260 ° C., and the treatment time is preferably in the range of 10 seconds to 90 minutes. The acrylic sol of the present invention can form a uniform film under the gelation conditions. Depending on the application, the cured film can be further subjected to printing, embossing, foaming and the like.

  The acrylic sol of the present invention can be applied as paints, inks, adhesives, sealing agents, vehicle undercoats, and the like, and these can be applied to molded products such as sundries, toys, industrial parts, and electrical parts. Moreover, for example, when applied to a sheet-like material such as paper or cloth, wallpaper, artificial leather, rug, medical sheet, waterproof sheet or the like can be obtained, and when applied to a metal plate, a corrosion-resistant metal plate can be obtained. it can.

Hereinafter, the present invention will be specifically described with reference examples, examples and comparative examples, but the present invention is not limited thereto.
The measurement or evaluation of physical property values in the following Reference Examples, Examples and Comparative Examples was performed by the following method.

(1) Average particle diameter It measured using the Horiba Seisakusho laser diffraction / scattering type particle size distribution measuring device LA-300.

(2) Storage stability The viscosity (V1) at 25 ° C. after 1 hour of preparation of the acrylic sol and the viscosity (V2) at 25 ° C. after standing at 35 ° C. for 10 days are BM type viscometer (manufactured by Tokimec) In rotor No. 4 was measured at 30 rpm, viscosity retention was obtained from the following formula, and storage stability was evaluated according to the following evaluation criteria.
Viscosity retention = V2 / V1
[Evaluation criteria for storage stability]
○: The viscosity retention is less than 2, and the storage stability is very good.
Δ: Viscosity retention is 2 or more and less than 3, and storage stability is almost good.
X: The viscosity retention is 3 or more, and the storage stability is extremely poor.

(3) Hardness After forming a sheet having a thickness of 3 mm at 150 ° C. using a compression molding machine, the hardness was measured using an A-type hardness meter (manufactured by Oscar) according to JIS K6253.

(4) Tensile strength and tensile elongation After forming a sheet having a thickness of 1 mm at 150 ° C. using a compression molding machine, measurement was performed according to JIS K6723 using Autograph AG-2000B (manufactured by Shimadzu Corporation). did.

(5) Bleed-out resistance After forming a sheet having a thickness of 1 mm at 150 ° C. using a compression molding machine, the bleed-out state of the plasticizer on the surface of the coating after being kept at 25 ° C. for 1 week is visually observed. And evaluated according to the following evaluation criteria.
[Evaluation criteria for bleed-out resistance]
○: No plasticizer bleed out ×: Plasticizer bleed out

Moreover, the compound name used in the reference example, the Example, and the comparative example, and its abbreviation [inside ()) are shown below.
Methyl methacrylate (MMA), n-butyl methacrylate (nBMA), isobutyl methacrylate (iBMA), 2-hydroxyethyl methacrylate (2HEMA), n-butyl acrylate (BA), methacrylic acid (MAA), aryl methacrylate (ALMA), polyethylene glycol # 400 dimethacrylate (PEG9G), n-octyl mercaptan (n-OM), potassium persulfate (KPS), diisononyl phthalate (DINP), resorcinol bisdiphenyl phosphate (RDP).
Moreover, "part" used in the following reference examples, examples, and comparative examples represents parts by mass.

Reference example 1
Production of acrylic polymer particles (a-1) (a) In a reactor equipped with a stirrer, thermometer, nitrogen gas introduction part, monomer introduction pipe and reflux condenser, 900 parts by mass of deionized water, lauryl 0.06 part by mass of sodium sulfate and 0.6 part by mass of sodium carbonate were charged, and the inside of the container was sufficiently replaced with nitrogen gas to make it substantially free of oxygen, and then the internal temperature was set to 80 ° C. Thereto, 30 parts by mass of a monomer mixture composed of 20% by mass of MMA and 80% by mass of iBMA was added and stirred for 10 minutes. Then, 0.03 parts by mass of KPS was added and stirring was continued for 120 minutes. Then, the polymerization reaction was further performed for 30 minutes.
(Ii) Next, 0.027 parts by mass of KPS was added to the reactor and stirred for 5 minutes, and then 270 parts by mass of monomer consisting of 35% by mass of MMA and 65% by mass of iBMA and 0.027 parts by mass of n-OM. The mixture consisting of was continuously added dropwise over 60 minutes, and after completion of the addition, the polymerization reaction was further carried out for 30 minutes so that the polymerization rate became 98% or more.
(C) Next, 0.027 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then a monomer mixture consisting of 50% by mass of MMA, 44% by mass of iBMA, 3% by mass of MAA and 3% by mass of 2HEMA was 240% by mass. The portion was continuously added dropwise over 60 minutes, and after completion of the addition, a polymerization reaction was further performed for 30 minutes so that the polymerization rate was 98% or more.
(D) Next, 0.01 parts by mass of KPS was added to the reactor and stirred for 5 minutes, and then 60 parts by mass of a monomer mixture consisting of 75% by mass of MMA, 24.5% by mass of iBMA and 0.5% by mass of PEG9G. Part is continuously dropped over 20 minutes, and after the addition is completed, the polymerization reaction is further performed for 60 minutes so that the polymerization rate becomes 98% or more, and the latex containing acrylic polymer particles (a-1) is obtained. Obtained. The acrylic polymer particles (a-1) belong to the multistage polymer particles (I). Moreover, the average particle diameter of this acrylic polymer particle (a-1) was 0.81 micrometer. A summary is shown in Table 1.

Reference example 2
Production of acrylic polymer particles (a-2) (a) In a reactor equipped with a stirrer, thermometer, nitrogen gas introduction part, monomer introduction pipe and reflux condenser, 900 parts by mass of deionized water, lauryl After charging 0.03 part by weight of sodium sulfate, 0.03 part by weight of sodium dodecylbenzenesulfonate and 0.6 part by weight of sodium carbonate, the inside of the container is sufficiently replaced with nitrogen gas to make it substantially free of oxygen. The internal temperature was set to 80 ° C. Then, 0.036 parts by mass of KPS was added and stirred for 5 minutes, and then 180 parts by mass of a monomer mixture composed of 40% by mass of MMA, 30% by mass of iBMA and 30% by mass of nBMA was continuously added dropwise over 45 minutes, After completion of the addition, a polymerization reaction was further performed for 30 minutes so that the polymerization rate was 98% or more.
(B) Next, 0.036 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then a single unit consisting of MMA 70% by mass, iBMA 13% by mass, nBMA 13% by mass, MAA 2% by mass and 2HEMA 2% by mass. A mixture comprising 180 parts by mass of the body and 0.018 parts by mass of n-OM was continuously added dropwise over 60 minutes, and after completion of the addition, a polymerization reaction was further performed for 30 minutes so that the polymerization rate was 98% or more.
(C) Next, 0.048 parts by mass of KPS was added to the reactor and stirred for 5 minutes, and then MMA 64.9% by mass, iBMA 17.5% by mass, nBMA 17.5% by mass and ALMA 0.1% by mass. 240 parts by mass of a monomer mixture consisting of the above was continuously added dropwise over 120 minutes, and after the addition was completed, the polymerization reaction was further carried out for 60 minutes so that the polymerization rate became 98% or more, and acrylic polymer particles ( A latex containing a-2) was obtained. The acrylic polymer particles (a-2) belong to the multistage polymer particles (I). The average particle size of the acrylic polymer particles (a-2) was 0.49 μm. A summary is shown in Table 1.

Reference example 3
Production of acrylic polymer particles (a-3) (a) In a reactor equipped with a stirrer, thermometer, nitrogen gas introduction part, monomer introduction pipe and reflux condenser, 900 parts by mass of deionized water, lauryl After 0.12 parts by mass of sodium sulfate and 0.8 parts by mass of sodium carbonate were charged and the inside of the container was sufficiently replaced with nitrogen gas to make it substantially free of oxygen, the internal temperature was set to 80 ° C. Thereto was added 0.3 parts by mass of KPS, and after stirring for 5 minutes, 180 parts by mass of a monomer mixture consisting of 30% by mass of MMA, 68.8% by mass of BA, 1% by mass of PEG9G and 0.2% by mass of ALMA was added over 60 minutes. Then, after the addition was completed, the polymerization reaction was further carried out for 30 minutes so that the polymerization rate was 98% or more.
(Ii) Next, 0.3 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then 300 parts by mass of a monomer consisting of 93% by mass of MMA, 5% by mass of BA and 2% by mass of MAA and n-OM0. A mixture of 0.030 parts by mass was continuously added dropwise over 180 minutes, and after completion of the addition, a polymerization reaction was further carried out for 30 minutes so that the polymerization rate was 98% or more.
(C) Next, 0.12 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then 120 parts by mass of a monomer mixture consisting of 89% by mass of MMA, 10% by mass of BA and 1% by mass of PEG9G was added for 60 minutes. Then, after completion of the addition, a polymerization reaction was further carried out for 60 minutes so that the polymerization rate became 98% or more to obtain a latex containing acrylic polymer particles (a-3). The acrylic polymer particles (a-3) belong to the multistage polymer particles (II). The average particle diameter of the acrylic polymer particles (a-3) was 0.56 μm. A summary is shown in Table 1.

Reference example 4
Production of acrylic polymer particles (a-4) (a) In a reactor equipped with a stirrer, thermometer, nitrogen gas introduction part, monomer introduction pipe and reflux condenser, 900 parts by mass of deionized water, lauryl 0.06 part by mass of sodium sulfate and 0.6 part by mass of sodium carbonate were charged, and the inside of the container was sufficiently replaced with nitrogen gas to make it substantially free of oxygen, and then the internal temperature was set to 80 ° C. Thereto, 30 parts by mass of a monomer mixture composed of 20% by mass of MMA and 80% by mass of iBMA was added and stirred for 10 minutes. Then, 0.03 parts by mass of KPS was added and stirring was continued for 120 minutes. Then, the polymerization reaction was further performed for 30 minutes.
(Ii) Next, 0.027 parts by mass of KPS was added to the reactor and stirred for 5 minutes, and then 270 parts by mass of monomer consisting of 35% by mass of MMA and 65% by mass of iBMA and 0.027 parts by mass of n-OM. The mixture consisting of was continuously added dropwise over 60 minutes, and after completion of the addition, the polymerization reaction was further carried out for 30 minutes so that the polymerization rate became 98% or more.
(C) Next, 0.027 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then a monomer mixture consisting of 50% by mass of MMA, 44% by mass of iBMA, 3% by mass of MAA and 3% by mass of 2HEMA was 240% by mass. The portion was continuously added dropwise over 60 minutes, and after completion of the addition, a polymerization reaction was further performed for 30 minutes so that the polymerization rate was 98% or more.
(D) Next, 0.01 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then a single unit consisting of MMA 75% by mass, iBMA 22.5% by mass, MAA 2% by mass and PEG9G 0.5% by mass. Acrylic polymer particles (a-4) were continuously added dropwise over a period of 20 minutes, and the polymerization reaction was further carried out for 60 minutes so that the polymerization rate was 98% or more. A latex containing was obtained. The acrylic polymer particles (a-4) belong to the multistage polymer particles (I). The average particle diameter of the acrylic polymer particles (a-4) was 0.79 μm. A summary is shown in Table 1.

Comparative Reference Example 1
Production of acrylic polymer (a-5) (a) In a reactor equipped with a stirrer, thermometer, nitrogen gas introduction part, monomer introduction pipe and reflux condenser, 900 parts by mass of deionized water, lauryl sulfuric acid 0.06 part by mass of sodium and 0.6 part by mass of sodium carbonate were charged and the inside of the container was sufficiently replaced with nitrogen gas to make it substantially free of oxygen, and then the internal temperature was set to 80 ° C. Thereto, 30 parts by mass of a monomer mixture composed of 20% by mass of MMA and 80% by mass of iBMA was added and stirred for 10 minutes. Then, 0.03 parts by mass of KPS was added and stirring was continued for 120 minutes. Then, the polymerization reaction was further performed for 30 minutes.
(Ii) Next, 0.027 parts by mass of KPS was added to the reactor and stirred for 5 minutes, and then 270 parts by mass of monomer consisting of 35% by mass of MMA and 65% by mass of iBMA and 0.027 parts by mass of n-OM. The mixture consisting of was continuously added dropwise over 60 minutes, and after completion of the addition, the polymerization reaction was further carried out for 30 minutes so that the polymerization rate became 98% or more.
(C) Next, 0.027 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then a monomer mixture consisting of 50% by mass of MMA, 44% by mass of iBMA, 3% by mass of MAA and 3% by mass of 2HEMA was 240% by mass. The portion was continuously added dropwise over 60 minutes, and after completion of the addition, a polymerization reaction was further performed for 30 minutes so that the polymerization rate was 98% or more.
(D) Next, 0.01 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then 60 parts by mass of a monomer mixture consisting of 75% by mass of MMA and 25% by mass of iBMA was continuously added over 20 minutes. Then, after completion of the addition, a polymerization reaction was further performed for 60 minutes so that the polymerization rate became 98% or more to obtain a latex containing acrylic polymer particles (a-5). This acrylic polymer (a-5) does not belong to the multistage polymer particles (I) or the multistage polymer particles (II). The average particle diameter of the acrylic polymer particles (a-5) was 0.83 μm. A summary is shown in Table 1.

Comparative Reference Example 2
Production of acrylic polymer (a-6) (a) In a reactor equipped with a stirrer, thermometer, nitrogen gas introduction part, monomer introduction pipe and reflux condenser, 900 parts by mass of deionized water, lauryl sulfuric acid 0.06 part by mass of sodium and 0.6 part by mass of sodium carbonate were charged and the inside of the container was sufficiently replaced with nitrogen gas to make it substantially free of oxygen, and then the internal temperature was set to 80 ° C. Thereto, 30 parts by mass of a monomer mixture composed of 20% by mass of MMA and 80% by mass of iBMA was added and stirred for 10 minutes. Then, 0.03 parts by mass of KPS was added and stirring was continued for 120 minutes. Then, the polymerization reaction was further performed for 30 minutes.
(Ii) Next, 0.027 parts by mass of KPS was added to the reactor and stirred for 5 minutes, and then 270 parts by mass of monomer consisting of 35% by mass of MMA and 65% by mass of iBMA and 0.027 parts by mass of n-OM. The mixture consisting of was continuously added dropwise over 60 minutes, and after completion of the addition, the polymerization reaction was further carried out for 30 minutes so that the polymerization rate became 98% or more.
(C) Next, 0.027 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then a monomer mixture consisting of 50% by mass of MMA, 44% by mass of iBMA, 3% by mass of MAA and 3% by mass of 2HEMA was 240% by mass. The portion was continuously added dropwise over 60 minutes, and after completion of the addition, a polymerization reaction was further performed for 30 minutes so that the polymerization rate was 98% or more.
(D) Next, 0.01 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then 60 parts by mass of a monomer mixture consisting of 60% by mass of MMA, 20% by mass of iBMA and 20% by mass of PEG9G was added for 20 minutes. Then, after completion of the addition, a polymerization reaction was further carried out for 60 minutes so that the polymerization rate became 98% or more to obtain a latex containing acrylic polymer particles (a-6). The acrylic polymer particles (a-6) do not belong to the multistage polymer particles (I) or the multistage polymer particles (II). The average particle diameter of the acrylic polymer particles (a-6) was 0.80 μm. A summary is shown in Table 1.

Comparative Reference Example 3
Production of acrylic polymer particles (a-7) (a) In a reactor equipped with a stirrer, thermometer, nitrogen gas introduction part, monomer introduction pipe and reflux condenser, 900 parts by mass of deionized water, lauryl After 0.12 parts by mass of sodium sulfate and 0.8 parts by mass of sodium carbonate were charged and the inside of the container was sufficiently replaced with nitrogen gas to make it substantially free of oxygen, the internal temperature was set to 80 ° C. Thereto was added 0.3 parts by mass of KPS, and after stirring for 5 minutes, 180 parts by mass of a monomer mixture consisting of 30% by mass of MMA, 68.8% by mass of BA, 1% by mass of PEG9G and 0.2% by mass of ALMA was added over 60 minutes. Then, after the addition was completed, the polymerization reaction was further carried out for 30 minutes so that the polymerization rate was 98% or more.
(Ii) Next, 0.3 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then 300 parts by mass of a monomer consisting of 93% by mass of MMA, 5% by mass of BA and 2% by mass of ALMA, and n-OM0. A mixture of 0.030 parts by mass was continuously added dropwise over 180 minutes, and after completion of the addition, a polymerization reaction was further carried out for 30 minutes so that the polymerization rate was 98% or more.
(C) Next, 0.12 parts by mass of KPS was put into the reactor and stirred for 5 minutes, and then 120 parts by mass of a monomer mixture consisting of 89% by mass of MMA, 10% by mass of BA and 1% by mass of PEG9G was added for 60 minutes. Then, after completion of the addition, a polymerization reaction was further carried out for 60 minutes so that the polymerization rate became 98% or more to obtain a latex containing acrylic polymer particles (a-7). The acrylic polymer (a-7) does not belong to the multistage polymer particles (I) or the multistage polymer particles (II). The average particle diameter of the acrylic polymer particles (a-7) was 0.56 μm. A summary is shown in Table 1.

Example 1
The latex containing the acrylic polymer particles (a-1) is pulverized using a spray dryer [L-8 type, manufactured by Okawahara Chemical Co., Ltd.], and an acrylic polymer powder (A- 1) was obtained. After adding 100 parts by mass of DINP to 100 parts by mass of the powder (A-1), mixing with a biaxial defoaming mixer (manufactured by Kodaira Seisakusho), deaeration to prepare an acrylic sol, storage stability, bleed-out resistance Property, hardness, tensile strength, and tensile elongation were evaluated. The results are shown in Table 2.

Example 2
The latex containing the acrylic polymer particles (a-2) is pulverized using a spray dryer [L-8 type, manufactured by Okawahara Chemical Co., Ltd.], and an acrylic polymer powder (A- 2) was obtained. After adding 100 parts by mass of DINP to 100 parts by mass of the powder (A-2), mixing with a biaxial defoaming mixer (manufactured by Kodaira Seisakusho), deaeration to prepare an acrylic sol, storage stability, bleed-out resistance Property, hardness, tensile strength, and tensile elongation were evaluated. The results are shown in Table 2.

Example 3
The latex containing the acrylic polymer particles (a-3) is pulverized using a spray dryer [L-8 type, manufactured by Okawahara Chemical Co., Ltd.], and an acrylic polymer powder (A- 3) was obtained. 100 parts by mass of RDP is added to 100 parts by mass of the powder (A-3), mixed with a biaxial defoaming mixer (manufactured by Kodaira Seisakusho), deaerated to prepare an acrylic sol, and then storage stability and bleed-out resistance Property, hardness, tensile strength, and tensile elongation were evaluated. The results are shown in Table 2.

Example 4
The latex containing the acrylic polymer particles (a-4) is pulverized using a spray dryer [L-8 type, manufactured by Okawahara Kako Co., Ltd.], and an acrylic polymer powder (A- 4) was obtained. 100 parts by mass of RDP is added to 100 parts by mass of the powder (A-4), mixed with a biaxial defoaming mixer (manufactured by Kodaira Seisakusho), deaerated to prepare an acrylic sol, and then storage stability and bleed-out resistance Property, hardness, tensile strength, and tensile elongation were evaluated. The results are shown in Table 2.

Comparative Example 1
The latex containing acrylic polymer particles (a-5) is pulverized using a spray dryer [L-8 type, manufactured by Okawahara Chemical Co., Ltd.], and an acrylic polymer powder (A- 5) was obtained. After adding 100 parts by mass of DINP to 100 parts by mass of the powder (A-5), mixing with a biaxial defoaming mixer (manufactured by Kodaira Seisakusho), deaeration to prepare an acrylic sol, storage stability, bleed-out resistance Property, hardness, tensile strength, and tensile elongation were evaluated. The results are shown in Table 2.

Comparative Example 2
The latex containing the acrylic polymer particles (a-6) is pulverized using a spray dryer [L-8 type, manufactured by Okawahara Koki Co., Ltd.], and the acrylic polymer powder (A- 6) was obtained. 100 parts by mass of DINP is added to 100 parts by mass of the powder (A-6), mixed with a biaxial defoaming mixer (manufactured by Kodaira Seisakusho), deaerated to prepare an acrylic sol, and then storage stability and bleed-out resistance Property, hardness, tensile strength, and tensile elongation were evaluated. The results are shown in Table 2.

Comparative Example 3
The latex containing acrylic polymer particles (a-7) is pulverized using a spray dryer [L-8 type, manufactured by Okawahara Chemical Co., Ltd.], and an acrylic polymer powder (A- 7) was obtained. 100 parts by weight of DINP is added to 100 parts by weight of the powder (A-7), mixed with a biaxial defoaming mixer (manufactured by Kodaira Seisakusho), deaerated to prepare an acrylic sol, and then storage stability and bleed-out resistance Property, hardness, tensile strength, and tensile elongation were evaluated. The results are shown in Table 2.

According to the present invention, an acrylic polymer powder excellent in storage stability is provided. Furthermore, the acrylic polymer powder provides an acrylic sol having excellent mechanical strength, flexibility and plasticizer retention, and does not generate hydrogen chloride gas upon incineration, and a molded product thereof. The acrylic sol can be applied as, for example, paints, inks, adhesives, sealing agents, vehicle undercoats, and the like, and the molded products are applied to molded products such as miscellaneous goods, toys, industrial parts, and electrical parts. can do. Moreover, if the molded product is applied to a sheet-like material such as paper or cloth, wallpaper, artificial leather, rug, medical sheet, waterproof sheet, etc. can be obtained, and if applied to a metal plate, a corrosion-resistant metal plate. It can be.

Claims (6)

An acrylic polymer powder obtained by coagulating and drying a latex containing acrylic polymer particles, wherein the acrylic polymer particles are contained in the latex containing the preceding polymer (Ia). Multi-stage polymer particles (I) obtained by forming a coalescence (Ib),
The first stage polymer (Ia) is 10 to 90% by mass of methyl methacrylate units and 90 to 10% by mass of other monofunctional monomer units copolymerizable with methyl methacrylate, A copolymer formed by two or more successive polymerization reactions having different monomer compositions from each other;
The post-stage polymer (Ib) is composed of 50 to 99.99% by mass of methyl methacrylate units, 49.99% by mass or less of other monofunctional monomer units copolymerizable with methyl methacrylate, and polyfunctional. A cross-linked polymer formed by a polymerization reaction of one step consisting of 0.01 to 10% by weight of a monomeric monomer unit or two or more consecutive monomer steps having different monomer compositions,
An acrylic polymer powder having a mass ratio of the former stage polymer (Ia) / the latter stage polymer (Ib) of 50/50 to 95/5. An acrylic polymer powder obtained by coagulating and drying a latex containing acrylic polymer particles, wherein the acrylic polymer particles are contained in the latex containing the previous-stage polymer (II-a). A multi-stage polymer particle (II) obtained by forming a coalescence (II-b) and further molding a post-stage polymer (II-c),
The pre-stage polymer (II-a) is 50-99.99 mass% of acrylic acid methyl ester units, 49.99 mass% or less of other monofunctional monomer units copolymerizable with acrylic acid methyl ester, and many It is a cross-linked polymer formed by a polymerization reaction consisting of 0.01 to 10% by mass of functional monomer units in one step or two or more consecutive monomer steps having different monomer compositions,
Middle stage polymer (II-b) is composed of 50 to 100% by mass of methyl methacrylate units and 50% by mass or less of other monofunctional monomer units copolymerizable with methyl acrylate, A polymer formed by two or more successive polymerization reactions with different monomer compositions;
The post-stage polymer (II-c) is composed of 50 to 99.99% by mass of methyl methacrylate units, 49.99% by mass or less of other monofunctional monomer units copolymerizable with methyl methacrylate, and polyfunctional. A cross-linked polymer formed by a polymerization reaction of one step consisting of 0.01 to 10% by weight of a monomeric monomer unit or two or more consecutive monomer steps having different monomer compositions,
Acrylic polymer in which the mass ratio of the pre-stage polymer (II-a) / middle-stage polymer (II-b) / post-stage polymer (II-c) is 10-30 / 30-85 / 5-50 Acrylic polymer powder as particles (II).   The acrylic polymer powder according to claim 1 or 2, wherein the coagulation drying is spray drying.   The acrylic polymer powder according to any one of claims 1 to 3, wherein all polymerization is performed by an emulsion polymerization method.   An acrylic sol containing the acrylic polymer powder according to any one of claims 1 to 4 and a plasticizer. A molded product obtained from the acrylic sol according to claim 5.