JP2008208180A - Acrylic polymer fine particle, its production method, and plastisol composition, and molded article using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide acrylic polymer fine particles which can give molded articles excellent in temporal stability and excellent in the flexibility and mechanical properties of the molded articles, when processed into a plastisol composition, and to provide a method for producing the same. <P>SOLUTION: The acrylic polymer fine particles have at least one peak in a region of ≥1,500,000 and at least one peak in a region of ≤150,000, respectively, when mass-average molecular weight is measured by GPC. The method for producing the acrylic polymer fine particles comprises adding and polymerizing a monomer in the presence of acrylic polymer fine particles having at least one peak in a range of ≥1,500,000, when measuring mass-average molecular wights by GPC, further forming an acrylic polymer having at least one peak in a range of ≤150,000, when measuring a mass-average molecular weight by GPC, and then recovering the acrylic polymer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to acrylic polymer fine particles and a method for producing the same. The present invention also relates to an acrylic plastisol composition in which acrylic polymer fine particles are dispersed in a plasticizer, and a molded article using the same. More specifically, acrylics are useful as molding materials for various plasticizers because they have excellent dispersibility, good temporal stability, and excellent flexibility and mechanical properties of molded products. The present invention relates to a plastic plastisol composition and a molded product obtained using the acrylic plastisol composition.

A plastisol composition obtained by dispersing polymer fine particles in a plasticizer is generally referred to as a paste resin and is currently widely used industrially. Specifically, for example, it is used as a coating material used for applications such as automobiles, flooring materials, wallpaper, and steel sheets, or as a molding material for slush molding, dip molding, rotation molding, etc. . In particular, vinyl chloride plastisol compositions using vinyl chloride polymer particles as polymer particles are widely used.
However, the vinyl chloride resin has a problem that dioxins, which are highly toxic substances, are generated when incinerated at a low temperature. In order to reduce the amount of dioxin generated, it is effective to reduce the amount of vinyl chloride resin used. Therefore, an acrylic plastisol composition using acrylic resin fine particles as polymer fine particles has been proposed.
In recent years, the required performance for acrylic plastisol compositions has been further increased. In particular, a glove obtained by dip molding a plastisol composition has a problem that the flexibility is not sufficient and it is difficult to wear it particularly in a low temperature atmosphere in winter. Also, since gloves are used in a wide range such as homes, cafeterias, hospitals, research laboratories, factories, etc., phthalate plasticizers that have been widely used for some purposes cannot be used because they are suspected as environmental hormone substances. Molding with excellent aging stability of plastisol composition and excellent flexibility and mechanical properties of various plasticizers with different polarities from phthalic plasticizers to non-phthalic plasticizers. There is a need for a plastisol composition that can provide a product.

For example, Patent Document 1 proposes an acrylic sol composition using core-shell structured acrylic polymer fine particles. A plastisol composition using a core polymer having a core / shell structure composed of a core polymer having a polymer composition compatible with a plasticizer and a shell polymer having a polymer composition incompatible with a plasticizer. The product tends to have a low viscosity change over time during storage, and the molded product obtained by using this plastisol composition has a small plasticizer bleed-out and has excellent flexibility and mechanical properties. Tends to be obtained.
For example, Patent Document 2 proposes to improve the aging stability of the plastisol composition by setting the mass average molecular weight of the acrylic polymer fine particles to more than 2 million.
WO2000 / 01748 publication JP 11-310681 A

In the fine particles described in Patent Document 1, the selection range of plasticizers that can be used is narrow, and plasticizers having different polarities cannot be used. In addition, acrylic polymer fine particles having a core / shell structure particle shape composed of a core polymer having a polymer composition compatible with a plasticizer and a shell polymer having a polymer composition incompatible with a plasticizer were used. In the plastisol composition, the core polymer is compatible with the plasticizer and is plasticized to improve the flexibility of the molded product. However, since the molecular weight is small and the plastic is easily plasticized, The flexibility of the molded product was not sufficient. On the other hand, since the shell polymer is incompatible with the plasticizer, the penetration of the plasticizer into the particles is prevented, the aging stability of the sol composition is improved, and the mechanical properties of the molded product are improved. Since the molecular weight is high and the core / shell particle structure is retained after molding, the flexibility of the molded product is not sufficient.
Moreover, in the plastisol composition obtained from Patent Document 2, the flexibility of the molded product is not sufficient. As a means of improving the flexibility, there is a method of increasing the content of the plasticizer. However, in this method, bleed out of the plasticizer increases from the obtained molded product, resulting in stickiness of the molded product surface, and the molded product. They are fused together, making it difficult to use. Further, the mechanical properties of the molded product are lowered, and the product is torn or punctured during use, so that the performance as a glove cannot be satisfied. In addition, the selection range of plasticizers that can be used is narrow, and it is extremely difficult to achieve high levels of both aging stability of the sol composition, flexibility of the molded product, and mechanical properties.
As described above, acrylics are useful as molding materials for various plasticizers because of excellent dispersibility, good temporal stability, and excellent flexibility and mechanical properties of molded products. At present, no polymer fine particles have been obtained.
An object of the present invention is an acrylic polymer fine particle capable of providing a molded product with excellent aging stability of a plastisol composition and excellent flexibility and mechanical properties of various plasticizers, An object of the present invention is to provide a production method thereof, an acrylic plastisol composition using the polymer fine particles, and a molded product thereof.

That is, the gist of the present invention resides in acrylic polymer fine particles having at least one peak at 1.5 million or more and 150,000 or less when the mass average molecular weight is measured by GPC.
In addition, the gist of the present invention is to add and polymerize a monomer in the presence of acrylic polymer fine particles having at least one peak at 1.5 million or more when the mass average molecular weight is measured by GPC. Furthermore, when the mass average molecular weight is measured by GPC, an acrylic polymer having at least one peak at 150,000 or less is formed, and then the acrylic polymer particles are recovered and the acrylic polymer particles are recovered. .
The gist of the present invention resides in an acrylic plastisol composition containing the acrylic polymer fine particles and a plasticizer.
Furthermore, the gist of the present invention resides in a molded product obtained from the acrylic plastisol composition.

  According to the present invention, various plasticizers have excellent dispersibility, good stability over time, and useful as a plastisol from which molded articles having excellent flexibility and mechanical properties can be obtained. Acrylic polymer fine particles and a method for producing the same can be provided.

Acrylic polymer fine particles The acrylic polymer fine particles used in the present invention have excellent dispersibility and stability over time with respect to a plasticizer, and are gelled by heating to impart desired physical properties to a molded product. Is a component for.
The acrylic polymer fine particles of the present invention have at least one peak at 1.5 million or more and 150,000 or less when the mass average molecular weight is measured by GPC.
As the particle structure of the acrylic polymer fine particles, a core / shell structure having two or more layers is preferable since further additional physical properties can be introduced into the plastisol composition as necessary. For example, an acrylic polymer fine particle having a core / shell structure made of a core polymer having a polymer composition compatible with a plasticizer and a shell polymer having a polymer composition incompatible with a plasticizer was used. The plastisol composition tends to have a low viscosity change over time during storage, and a molded article obtained using the plastisol composition has a small plasticizer bleed-out and has excellent flexibility and mechanical properties. There is a tendency to obtain a molded product.
In the core / shell type polymer particles, it is preferable that the core polymer has a composition compatible with the plasticizer, and the shell polymer has a composition incompatible with the plasticizer.
The polymer composition that is compatible with the plasticizer here is a molded product obtained by mixing the plasticizer and the polymer composition in a mass ratio of 1: 1, and then molding at a molding temperature of 130 to 200 ° C. To a polymer composition in which no bleed-out of the plasticizer is observed. The polymer composition incompatible with the plasticizer is mixed in the same manner as described above, and then the plasticizer and the polymer composition are molded at the molding temperature. It refers to a polymer composition in which many bleedouts are observed.

At this time, when the mass average molecular weight is measured by GPC, an acrylic polymer having at least one peak at 1.5 million or more is used as a core polymer, thereby increasing the entanglement due to the network chain of the resin, and the sol composition Under the temperature at which the product is stored, the plasticizer can be prevented from entering the particles and the plasticization can be suppressed. On the other hand, at the temperature at which the molding is performed, the entanglement is reduced by the thermal motion of the resin network chain. It is possible to improve the temporal stability of the sol composition without hindering the penetration of the plasticizer into the particles and without lowering the flexibility of the molded product.
On the other hand, when the weight average molecular weight is measured by GPC as the shell polymer, an acrylic polymer having at least one peak at 150,000 or less is used, so that the plasticizer can be used at the temperature at the time of storage of the sol composition. The core / shell structure has a core / shell structure because the heat melting property is improved when the sol composition is thermoformed while maintaining the aging stability of the sol composition without degrading the ability to suppress the penetration of particles into the particles. Since the particle structure is destroyed, the core polymer of the compatible component becomes a sea layer, and the shell polymer of the incompatible component becomes an island, forming a different morphology. It is possible to achieve both stability and flexibility of the molded product, mechanical properties, and suppression of bleed out of the plasticizer at a high level.

The core polymer of the acrylic polymer fine particles is preferably a polymer having a peak at 2 million or more, more preferably 2.5 million or more, and most preferably 3 million or more from the viewpoint of the temporal stability of the sol composition. Polymers are preferably used. In addition, a polymer having a peak at 15 million or less is preferable, and a polymer having a peak at 10 million or less is more preferable from the viewpoint of the meltability of the acrylic polymer fine particles in the sol composition.
From the viewpoint of the flexibility of the molded product, the acrylic polymer fine particle shell polymer is preferably a polymer having a peak at 150,000 or less, more preferably 100,000 or less, when the mass average molecular weight is measured by GPC. 10,000 or less is more preferable, and 40,000 or less is most preferable. In addition, a polymer having a peak at 5000 or more is preferable from the viewpoint of stability over time of the sol composition, and 10,000 or more is more preferable.
The ratio of the weight average molecular weight to the number average molecular weight of the acrylic polymer fine particles is not particularly limited, but the lower limit is preferably 15 or more, more preferably 20 or more, and particularly preferably 30 or more. The upper limit is preferably 200 or less, and more preferably 150 or less.
The core / shell ratio constituting the acrylic polymer fine particles is such that when the total of the core polymer and the shell polymer is 100 parts by mass, the core polymer is 50 parts by mass or more from the viewpoint of improving the flexibility of the molded product. Is preferable, 60 parts by mass or more is more preferable, and 70 parts by mass or more is particularly preferable.
Since the acrylic polymer fine particles of the present invention have good dispersibility in a plasticizer, the volume primary average particle size is preferably 400 nm or more. From the viewpoint of the viscosity and aging stability of the plastisol composition, 450 nm or more is more preferable, and 500 nm or more is particularly preferable. Moreover, it is preferable from a viewpoint that a particle diameter is 3 micrometers or less, and a particle | grain disperse | distributes stably, without sedimenting.

A method for producing the acrylic polymer fine particles is not particularly limited, and known methods such as an emulsion polymerization method, a fine suspension polymerization method, and a suspension polymerization method can be used.
Among them, it is preferable to adjust by a soap-free emulsion polymerization method, and when emulsifier micelles are present during seed particle polymerization, the particle diameter becomes small. Therefore, the polymerization is preferably carried out in the absence of emulsifier micelles. To the seed particles obtained by polymerization in the absence of emulsifier micelles, an acrylic unsaturated monomer is added to the seed particles and polymerized at least once. In the presence, the operation of adding and polymerizing the acrylic unsaturated monomer is performed at least once.

Examples of the acrylic polymer constituting the acrylic polymer fine particles include a polymer obtained by using an acrylic unsaturated monomer such as (meth) acrylic acid ester as a main component. In addition, (meth) acrylic acid ester is a general term for acrylic acid ester and methacrylic acid ester.
Specific examples of typical acrylic unsaturated monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, (meth ) (Meth) acrylic acid esters of linear alkyl alcohols such as t-butyl acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate; cyclohexyl (meth) acrylate And (meth) acrylic acid esters of cyclic alkyl alcohols. Among them, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate can be easily obtained and are industrially practical. It is preferable in terms of conversion. However, it is not limited to these acrylic unsaturated monomers.
Furthermore, unsaturated monomers other than those described above can be used alone or in combination with the unsaturated monomers. Examples of the unsaturated monomer include methacrylic acid, acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, 2-succinoloyloxyethyl methacrylate, 2-malenoyloxyethyl methacrylate, and methacrylic acid. Carboxyl group-containing unsaturated monomers such as 2-phthaloyloxyethyl and 2-hexahydrophthaloyloxyethyl methacrylate; sulfonic acid group-containing unsaturated monomers such as allylsulfonic acid; (meth) acrylic acid acetoacetate Carbonyl group-containing (meth) acrylic esters such as chiethyl; hydroxyl group-containing (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 4-hydroxybutyl and the like ( (Meth) acrylic acid esters; epoxy groups such as glycidyl (meth) acrylate (Meth) acrylic acid esters; amino group-containing (meth) acrylic acid esters such as N-dimethylaminoethyl (meth) acrylate and N-diethylaminoethyl (meth) acrylate; (meth) acrylamide, diacetone (meta) ) Acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, (meth) acrylamide such as N-butoxymethyl (meth) acrylamide; Urethane modified (meth) acrylate Epoxy modified (meth) acrylates; silicone modified (meth) acrylates and the like. These unsaturated monomers can be properly used depending on the application.
Among these, methacrylic acid, acrylic acid, 2-hydroxyethyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate are easily available and are preferred from the viewpoint of industrial practical use. However, it is not limited to these acrylic unsaturated monomers.

The composition of the core polymer constituting the acrylic polymer fine particles is 0.1 mol% or more in 100 mol% of the core polymer from the viewpoint of the balance between the temporal stability of the acrylic sol composition, the flexibility of the molded product, and the mechanical properties. It is preferable to contain 5 mol% or more of isobutyl methacrylate and a carboxyl group-containing monomer. The preferable range of the carboxyl group-containing monomer is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, and particularly preferably 1 mol% or more in 100 mol% of the core polymer. The upper limit is that the water-soluble resin is by-produced and becomes a binder that binds the polymer fine particles to each other at the time of drying, and the dispersibility of the acrylic polymer fine particles in the plasticizer is reduced. It is preferably 10 mol% or less, more preferably 5 mol% or less, and particularly preferably 3 mol% or less. As the carboxyl group-containing monomer, methacrylic acid and acrylic acid are preferable because they can be easily obtained and have excellent copolymerizability with an acrylic unsaturated monomer.
The preferable range of isobutyl methacrylate is preferably 5 mol% or more, more preferably 10 mol% or more, and particularly preferably 15 mol% or more in 100 mol% of the core polymer. The upper limit is preferably 90 mol% or less, particularly preferably 80 mol% or less, in 100 mol% of the core polymer.
More specifically, by using a specific addition amount of the carboxyl group-containing monomer, it becomes possible to introduce carboxyl groups on the particle surface, and heat fusion between the polymer primary fine particles during drying is suppressed. The dispersibility of the acrylic polymer fine particles in the agent is improved, and the stability over time of the acrylic sol composition and the flexibility and mechanical properties of the molded product can be achieved at a high level. Further, by using a specific addition amount of isobutyl methacrylate, the glass transition temperature of the core polymer can be increased without lowering the compatibility with the plasticizer, so that the heat between the polymer primary fine particles during drying can be increased. It is possible to suppress fusion, and as a result, it is possible to disperse the polymer at the primary fine particle level in the plasticizer, the aging stability of the acrylic sol composition, the flexibility of the molded product, the mechanical properties, the plasticity. It becomes possible to achieve a high level of suppression of the bleeding out of the agent.
The shell polymer constituting the acrylic polymer fine particles is preferably a shell polymer having two or more layers in which the carboxyl group-containing monomer is increased in multiple stages from the viewpoint of the temporal stability of the sol composition. As the carboxyl group-containing monomer, methacrylic acid and acrylic acid are preferable because they can be easily obtained and have excellent copolymerizability with an acrylic unsaturated monomer. The lower limit of the preferable range of the carboxyl group-containing monomer of the shell polymer of each layer is preferably 1 mol% or more, more preferably 3 mol% or more, and particularly preferably 5 mol% or more in 100 mol% of the shell polymer. The upper limit is preferably 25 mol% or less, more preferably 20 mol% or less, in 100 mol% of the shell polymer, from the viewpoint that the water-soluble resin is by-produced and the dispersibility of the acrylic polymer fine particles in the plasticizer is reduced. 15 mol% or less is particularly preferable.

The polymerization initiator used when preparing seed particles by soap-free emulsion polymerization is not particularly limited as long as it is a polymerization initiator soluble in an aqueous dispersion medium. For example, hydrogen peroxide, potassium persulfate, Water-soluble peroxides such as sodium sulfate and ammonium persulfate; water-soluble azo compounds such as azobiscyanovaleric acid and 2,2′-azobis- (2-amidinopropane) dihydrochloride, and the like. 1 type (s) or 2 or more types can be used.
Moreover, you may use the redox initiator system which used the reducing agent together with the above-mentioned polymerization initiator. Examples of the reducing agent include sulfites such as sodium sulfite and sodium hydrogen sulfite. Of these, persulfates such as potassium persulfate and ammonium persulfate are preferable, and potassium persulfate is more preferable in that the aggregation of polymer fine particles tends to be reduced. Further, the amount of the polymerization initiator used is not particularly limited, but when the mass average molecular weight of the core polymer of the polymer fine particles is 1,500,000 or more, 100 parts by mass of the unsaturated monomer constituting the polymer fine particles. Is preferably 0.01 parts by mass or less, more preferably 0.005 parts by mass or less, and particularly preferably 0.003 parts by mass or less.
If the volume primary particle diameter of the polymer fine particles is as large as 400 nm or more, it becomes very difficult to make the mass average molecular weight 1.5 million or more, and the polymerization is easily deactivated with a small amount of dissolved oxygen. Therefore, in order to produce high molecular weight acrylic polymer fine particles, it is necessary to carry out the reaction under the condition that the amount of the polymerization initiator is extremely small and the oxygen concentration of the reaction system aqueous phase is kept low.
In addition, when a polymer having a peak at 150,000 or less is used as the shell polymer when the mass average molecular weight is measured by GPC, addition of a chain transfer agent and / or initiation of polymerization when the shell polymer is polymerized It is preferable to add an additional agent. The chain transfer agent is not particularly limited and may be appropriately selected from known chain transfer agents. For example, n-octyl mercaptan, n-dodecyl mercaptan, n-lauryl mercaptan, tert-dodecyl mercaptan, thiol. Examples include octyl glycolate, methoxybutyl thioglycolate, octyl mercaptopropionate, methoxybutyl mercaptopropionate, and tridecyl mercaptopropionate. The addition amount of the chain transfer agent is not particularly limited, but is preferably 0.1% by mass or more with respect to 100 parts by mass of the unsaturated monomer of the shell polymer from the viewpoint of setting the mass average molecular weight to 150,000 or less. More preferably, the content is 0.3% by mass or more, and particularly preferably 0.6% by mass or more.

The additional polymerization initiator is not particularly limited, and specific examples include benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, Oil-soluble peroxides such as diisopropylbenzene hydroperoxide; oil-soluble azo compounds such as 2,2′-azobisisobutyronitrile and 2,2′-azobis- (2,4-dimethylvaleronitrile); Water-soluble peroxides such as hydrogen, potassium persulfate, sodium persulfate and ammonium persulfate; Water-soluble azo compounds such as azobiscyanovaleric acid and 2,2′-azobis- (2-amidinopropane) dihydrochloride Of these, one or more of these can be used. Moreover, you may use the redox initiator system which used together the reducing agent and the chelating agent as needed with the above-mentioned polymerization initiator. Examples of the reducing agent include alkali metal formaldehyde sulfoxylates such as Rongalite (formaldehyde sodium sulfoxylate); sulfites such as sodium sulfite and sodium bisulfite; pyrosulfites such as sodium pyrosulfite; sodium thiosulfate; Thiosulfates such as thiourea; phosphorous acid or salts thereof such as phosphorous acid and sodium phosphite; pyrophosphites such as sodium pyrophosphite; mercaptans; ascorbine such as ascorbic acid and sodium ascorbate Examples include acids or salts thereof; erythorbic acid or salts thereof such as erythorbic acid and sodium erythorbate; sugars such as glucose and dextrose; metal salts such as ferrous sulfate and copper sulfate. Examples of chelating agents include sodium pyrophosphate and ethylenediaminetetraacetate.
The structure of the acrylic polymer fine particles as a dry powder is not particularly limited, but for ease of handling as a powder, a large number of polymer primary fine particles obtained by polymerization are aggregated to form aggregated particles (secondary particles). It is preferable to form. The volume average particle size of the aggregated particles is preferably less than 100 μm because the smoothness of the cured film and the surface of the molded product tends to be good.
The method for preparing the acrylic polymer aggregated particles can be appropriately selected from known methods. For example, a method such as a (wet) coagulation method or a spray drying method may be appropriately selected and used. Among them, in a method for producing agglomerated particles (so-called spray drying method) in which an emulsion of acrylic polymer particles is spray-dried in a dryer with a drying heating gas, the temperature of the drying heating gas at the outlet of the drying chamber is acrylic. It is preferably lower than the average glass transition temperature Tg of the entire polymer polymer particles. Here, when the outlet temperature of the drying chamber is lower than the glass transition temperature Tg, aggregated particles having excellent pulverization properties of the aggregated particles can be obtained.

Plasticizer The plasticizer used in the plastisol composition of the present invention is not particularly limited, and may be appropriately selected from known plasticizers. Specific examples include phthalate plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, and butyl benzyl phthalate; Adipate plasticizers such as dimethyl adipate, dibutyl adipate, diisobutyl adipate, dihexyl adipate, di-2-ethylhexyl adipate, diisononyl adipate, dibutyl diglycol adipate; trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, Tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, triphenyl Phosphate ester plasticizers such as silenyl phosphate and cresyl phenyl phosphate; Trimellitic ester plasticizers such as tri-2-ethylhexyl trimellitate; Dimethyl sebacate, dibutyl sebacate, di-2-ethylhexyl sebacate Sebacic acid ester plasticizers such as poly-1,3-butanediol adipate, etc .; aliphatic polyester plasticizers such as epoxidized soybean oil; alkyl sulfonic acids such as alkylsulfonic acid phenyl esters Examples thereof include phenyl ester plasticizers; alicyclic dibasic acid ester plasticizers; polyether plasticizers such as polypropylene glycol and polybutylene glycol; and acetyl tributyl citrate.
The plasticizers can be used singly or in combination of two or more as required, and the blending amount can be appropriately changed as desired.
The blending amount of the plasticizer is preferably 35 to 350 parts by mass, more preferably 40 to 300 parts by mass, and particularly preferably 45 to 250 parts by mass with respect to 100 parts by mass of the acrylic polymer fine particles.

Various additives or fillers can be blended in the plastisol composition of the present invention depending on applications. Additives and fillers include, for example, calcium carbonate, aluminum hydroxide, baryta, clay, colloidal silica, mica powder, silica sand, diatomaceous earth, kaolin, talc, bentonite, glass powder, aluminum oxide and other inorganic fillers, titanium oxide , Pigments such as carbon black, diluents such as mineral terpenes and mineral spirits, thickeners such as zinc octylate, defoaming agents, antifungal agents, deodorants, antibacterial agents, surfactants, lubricants, UV absorbers A fragrance, a foaming agent, a leveling agent, an adhesive and the like can be blended as necessary.
As a method for preparing the plastisol composition, a known method may be appropriately selected and used. For example, acrylic polymer fine particles, a plasticizer and other compounding agents may be mixed in a kneading pot at one time, and in order to knead more strongly, acrylic polymer aggregated particles, a part of the plasticizer, and other The compounding agent may be kneaded first, and finally the remaining plasticizer may be added and kneaded. For the purpose of preventing the temperature of the resin from rising during kneading, a plasticizer and other compounding agents may be kneaded in advance, and finally acrylic polymer aggregated particles may be added and kneaded.
As a device for preparing the plastisol composition, a known device may be appropriately selected and used. Examples of the apparatus include a pony mixer, a change can mixer, a Hobart mixer, a planetary mixer, a butterfly mixer, a raking machine, a kneader, a three-roll mill, a ball mill, and a vacuum mixer.
If the plastisol composition is heated to be gelled to form a film, a desired molded product can be obtained. Examples of a method for obtaining a molded product using a plastisol composition include molding methods such as a dip molding method, a cast molding method, a splash molding method, and a rotational molding method.
The plastisol composition can be used as a coating material in addition to the molding material. The application method is not particularly limited. Specific examples of the method for applying the plastisol composition include a dip coating method, a spray coating method, a knife coating method, a roll coating method, a curtain flow coating method, a brush coating method, and an electrostatic coating method.
Thus, a glove can be obtained by using the plastisol composition of the present invention. In addition to gloves, it is possible to obtain molding materials such as vinyl leather, dolls, toys, flooring materials, sponge products, automobile parts, industrial machine parts, etc., and coating materials such as wallpaper, steel plates, and automotive coating materials.

Hereinafter, the present invention will be described in detail using examples. In each example, “part” means “part by mass”. Moreover, each evaluation was implemented with the following method.
(1) [Measurement method of volume average primary particle diameter of fine particles]
The emulsion before drying was set to 2 with a circulation level in the tank and a relative refractive index of 1.12 using a laser diffraction / scattering particle size distribution analyzer (LA-920 manufactured by Horiba, Ltd.), and then distilled water was used as a dispersion medium. As an example, an ultrasonic wave with an output of 4.3 W and a frequency of 22.5 kHz was irradiated for 1 minute, and the measurement was performed after preparation so that the transmittance was within the range of 75 to 95%. The median diameter calculated from the volume standard was defined as the volume average primary particle diameter of the fine particles.
(2) [Calculation method of glass transition temperature Tg of acrylic polymer fine particles]
The glass transition temperature Tg of the acrylic polymer fine particles was calculated from the Fox equation (1).
1 / (Tg + 273.4) = Σ {Wi / (Tgi + 273.4)} (1)
Wi: Mass fraction of monomer i Tgi: Glass transition temperature Tg (° C.) of homopolymer composed of monomer i
For the homopolymer Tg of monomer i, data described in Polymer Data Handbook Fundamentals (first edition of Polymer Society) can be used. The Tg of the resin not described can be obtained from DSC measurement which is a known technique.
(3) [Mass average molecular weight]
A polystyrene equivalent value measured under the following conditions by GPC (gel permeation chromatography) method was defined as the mass average molecular weight of the polymer.
-Equipment: High-speed GPC equipment HLC-8020 manufactured by Tosoh Corporation
-Column: manufactured by Tosoh Corporation, three TSKgelGMHXL are connected in series.-Oven temperature: 38 ° C
・ Eluent: Tetrahydrofuran ・ Sample concentration: 0.4% by mass
・ Flow rate: 1 mL / min ・ Injection volume: 0.1 mL
・ Detector: RI (differential refractometer)
(4) [Viscosity and aging stability evaluation of sol composition]
After keeping the plastisol composition in a thermostatic bath at 25 ° C. for 2 hours, using a B8H viscometer (manufactured by Tokyo Keiki Co., Ltd., product name: “B8H viscometer”, rotor: No. 7), the number of revolutions The viscosity after 1 minute was measured at 5 rpm, and this was defined as the initial viscosity η1. Further, this was stored in a constant temperature water bath at 40 ° C. for 10 days, and then kept in a constant temperature bath at 25 ° C. for 2 hours. Then, the viscosity was measured under the same apparatus and measurement conditions, and this was regarded as viscosity η2 after aging. The temporal stability of the sol was calculated and evaluated by the following formula (thickening rate).
Thickening rate (%) = η2 / η1 × 100-100
“◎”: less than 100% “◯”: less than 250% “×”: 250% or more (5) [Mechanical Properties Evaluation of Molded Product]
The plastisol composition was cast on a Teflon (registered trademark) -coated iron plate (thickness 1 mm) so as to have a wet film thickness of 2 mm, and this was placed in a gear oven at 160 ° C. and heated for 10 minutes. Obtained. After peeling this from the metal plate, it was cut out with dumbbell No. 3 according to the method described in JIS K-7113, and the tensile measuring device (manufactured by Shimadzu Corporation ■ tensile measuring device (trade name “Autograph AG” -IS 5 kN "), the mechanical properties were measured. The test speed was 200 mm / min. The mechanical properties were evaluated according to the following criteria.
Tensile strength “◎”: Tensile strength 5 MPa or more “O”: Tensile strength 3 MPa or more to less than 5 MPa “X”: Tensile strength less than 3 MPa Tensile elongation “O”: Tensile elongation 400% or more “X”: Tensile strength is less than 400% (6) [Flexibility evaluation of molded products]
The plastisol composition was cast on a Teflon (registered trademark) -coated iron plate (thickness 1 mm) so as to have a wet film thickness of 2 mm, and this was placed in a gear oven at 160 ° C. and heated for 10 minutes. Obtained. After peeling this from the metal plate, it was cut out with dumbbell No. 3, and was subjected to tensile deformation at an environmental temperature of 23 ° C. with a tensile measuring device (manufactured by Shimadzu Corporation ■ made of tensile measuring device (trade name “Autograph AG-IS 5kN”). A hysteresis test was performed, where the test speed was 50 mm / min, and the displacement was 40% in terms of elongation.The hysteresis test was repeated three times in succession (outward tension in the first test) The area (S1) given by the SS curve and the area (S2) given by the SS curve in the return path (at the time of return) are calculated, and the hysteresis storage rate = S2 / S1 × 100 (%) is calculated. The evaluation was based on the following criteria as an index of flexibility.
Mechanical properties were evaluated according to the following criteria.
“◎”: Hysteresis storage rate of 75% or more “O”: Hysteresis storage rate of 65% or more to less than 75% “X”: Hysteresis storage rate of less than 65%

[Preparation of acrylic polymer fine particles (P1)]
Into a 2 liter four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel and cooling tube, 476 parts of pure water was put, and nitrogen gas was bubbled for 70 minutes to dissolve dissolved oxygen in the pure water. Replaced. Next, after changing the nitrogen gas to a flow, 22.8 parts of methyl methacrylate (trade name “Acryester M” manufactured by Mitsubishi Rayon) and n-butyl methacrylate (trade name “Acryester B” manufactured by Mitsubishi Rayon) 17 4 parts were added and the temperature was raised to 82 ° C. while stirring at 250 rpm. When the internal temperature reached 82 ° C., the initiator solution (K1) shown in Table 1 was added to the flask all at once to initiate polymerization. Thereafter, the mixture was stirred at 82 ° C. for 90 minutes to obtain a seed particle emulsion.
Next, the internal temperature was lowered to 80 ° C., and nitrogen gas was introduced into the seed particle emulsion at a rate of 100 ml / min for 2 hours in advance to replace the dissolved oxygen. The emulsion was added dropwise over 150 minutes to be absorbed and polymerized by the seed particles. After completion of the addition, the emulsion was stirred at 80 ° C. for 30 minutes to obtain an emulsion of core particles. The obtained emulsion of core particles was sampled and the molecular weight was measured. The core polymer had a peak at a weight average molecular weight of 2.4 million.
Next, the initiator solution (K2) shown in Table 1 was dropped into the flask over 15 minutes to the polymer emulsion of the core particles, and then stirred and held at 80 ° C. for 15 minutes. Next, the unsaturated monomer (M2) emulsion shown in Table 1 was added dropwise to the polymer emulsion over 45 minutes, and the mixture was stirred and held at 80 ° C. for 15 minutes to conduct polymerization of shell 1, and the core / shell A 1 particle emulsion was obtained. Next, the unsaturated monomer (M3) emulsion shown in Table 1 was dropped into the emulsion particles of 1 core / shell particle over 20 minutes, and the mixture was stirred and held at 80 ° C. for 60 minutes to polymerize the shell 2. Thus, a core / shell 1 / shell 2 type polymer emulsion was obtained.
The core / shell 1 / shell 2 type polymer emulsion is cooled to room temperature, filtered through a nylon mesh (manufactured by NBC, trade name “N-No110S 115”), and then spray dryer (Okawara Chemical Co., Ltd. CL) -8 type), and spray-dried at an inlet temperature of 150 ° C., an outlet temperature of 65 ° C. and an atomizer speed of 20000 rpm, and then sieved with a sieve having an opening of 250 μm, and acrylic polymer fine particles having a volume average primary particle size of 588 nm (P1) was obtained.
When GPC was measured, it had a peak at 40,000 in addition to a peak of 2.4 million in mass average molecular weight. The ratio of the weight average molecular weight to the number average molecular weight was 58.
Table 1 shows the composition and physical properties of the acrylic polymer fine particles (P1).

[Preparation of acrylic polymer fine particles (P2) to (P5)]
Polymer fine particles (P2) to (P5) were prepared in the same manner as the polymer fine particles (P1) except that the monomers and initiators for core dripping and shell dripping were changed to those shown in Table 1, respectively. The dropping rate of the unsaturated monomer, spray drying conditions, and the like are the same as those for the polymer fine particles (P1). The composition and physical properties are shown in Table 1.

[Example 1]
100 parts of acrylic polymer fine particles (P1) and 100 parts of diisononyl phthalate (trade name “DINP” manufactured by J-PLUS) as a plasticizer are weighed, and a vacuum mixer (trade name “ARV-200” manufactured by Sinky Corporation) is measured. ) At a rotational speed of 2000 rpm for 10 seconds (atmospheric pressure: 0.1 MPa). Subsequently, the pressure was further reduced to 2.7 kPa, and the mixture was mixed with a vacuum mixer at a rotation speed of 2000 rpm for 110 seconds to obtain a uniform plastisol composition. The viscosity and aging stability of the plastisol composition at that time were evaluated. Next, the plastisol composition was cast to a thickness of 2 mm on a Teflon (registered trademark) -coated iron plate (thickness 1 mm), and this was placed in a 160 ° C. hot air oven for 10 minutes to obtain a molded product. It was. The mechanical properties and flexibility of the molded product at that time were evaluated. The plasticizer was changed to mezamol (alkylsulfonic acid phenyl ester type (trade name “Mezamol” manufactured by Bayer) or ATBC (acetyl tributyl citrate (trade name “Monocizer ATBC” manufactured by Dainippon Ink and Chemicals, Inc.)) Similarly, the viscosity and stability over time of the sol composition, the mechanical properties and flexibility of the molded article were evaluated, and the sol composition and evaluation results are shown in Table 2.

[Examples 2-3, Comparative Examples 1-2]
A uniform plastisol composition was produced, molded and evaluated in the same manner as in Example 1 except that the acrylic polymer fine particles listed in Table 2 were used. The evaluation results are shown in Table 2.
As is clear from the results of Examples 1 to 3, with respect to various plasticizers, the temporal stability in the sol composition is excellent, and the flexibility, tensile strength and elongation of the molded product are high, and the toughness is high. Excellent and mechanical properties are good. On the other hand, in Comparative Example 1, the temporal stability of the sol composition with respect to various plasticizers is poor, and the flexibility of the molded product is poor. Comparative Example 2 is inferior in flexibility and elongation of the molded product, although the temporal stability of the sol composition with respect to various plasticizers is good.

表中の略号：
「−」は、未添加または、未評価であることを示す。
「ＭＭＡ」：メチルメタクリレート（三菱レイヨン製、商品名「アクリエステルＭ」）
「ｎＢＭＡ」：ｎ−ブチルメタクリレート（三菱レイヨン製、商品名「アクリエステルＢ」）
「ｉＢＭＡ」：ｉ−ブチルメタクリレート（三菱レイヨン製、商品名「アクリエステルＩＢ」）
「ＡＡ」：アクリル酸（三菱化学製、商品名「アクリル酸」）
「ＭＡＡ」：メタクリル酸（三菱レイヨン製、商品名「メタクリル酸」）
「ＯＴＧ」：チオグリコール酸２−エチルヘキシル（淀化学製）
「ＯＴＰ」：ジオクチルスルホコハク酸ナトリウム（花王製、商品名「ペレックスＯＴＰ」）
「ＫＰＳ」：過硫酸カリウム（関東化学製）

Abbreviations in the table:
“-” Indicates no addition or no evaluation.
"MMA": Methyl methacrylate (Made by Mitsubishi Rayon, trade name "Acryester M")
“NBMA”: n-butyl methacrylate (Made by Mitsubishi Rayon, trade name “Acryester B”)
“IBMA”: i-butyl methacrylate (trade name “Acryester IB” manufactured by Mitsubishi Rayon)
“AA”: Acrylic acid (Mitsubishi Chemical, trade name “acrylic acid”)
“MAA”: methacrylic acid (trade name “methacrylic acid”, manufactured by Mitsubishi Rayon)
“OTG”: 2-ethylhexyl thioglycolate (manufactured by Sakai Chemical)
“OTP”: Sodium dioctyl sulfosuccinate (trade name “Perex OTP”, manufactured by Kao)
"KPS": Potassium persulfate (manufactured by Kanto Chemical)

「ＤＩＮＰ」：ジイソノニルフタレート（ジェイプラス社製、商品名「ＤＩＮＰ」）
「メザモール」：アルキルスルホン酸フェニルエステル系（バイエル社製、商品名「メザモール」）
「ＡＴＢＣ」：クエン酸アセチルトリブチル（大日本インキ化学工業製、商品名「モノサイザーＡＴＢＣ」）

“DINP”: Diisononyl phthalate (trade name “DINP” manufactured by J-Plus)
“Mezamol”: Phenyl ester of alkylsulfonic acid (manufactured by Bayer, trade name “Mezamol”)
"ATBC": Acetyl tributyl citrate (Dainippon Ink Chemical Co., Ltd., trade name "Monocizer ATBC")

Claims (4)

Acrylic polymer fine particles having at least one peak at 1.5 million or more and 150,000 or less when the mass average molecular weight is measured by GPC. When the mass average molecular weight is measured by GPC, a monomer is added and polymerized in the presence of acrylic polymer fine particles having at least one peak at 1.5 million or more, and the mass average molecular weight is further determined by GPC. A method for producing acrylic polymer particles, wherein an acrylic polymer is collected after forming an acrylic polymer having at least one peak at 150,000 or less when measured. An acrylic plastisol composition comprising the acrylic polymer fine particles according to claim 1 and a plasticizer. A molded article obtained from the acrylic plastisol composition according to claim 3.