JP5063043B2 - Acrylic polymer fine particles for soft molding, soft acrylic resin composition using the same, and acrylic soft sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide acrylic polymer fine particles for soft molding having high plasticizer absorbability together with good processability and mechanical strength. <P>SOLUTION: The acrylic polymer fine particles for soft molding contain a polymer component (P1) able to be plasticized with diisononyl phthalate and having &ge;400,000 mass average molecular weight and have &ge;0.4mL/g amount of oil adsorption measured by using linseed oil and 8-30m<SP>2</SP>/g specific surface area measured by nitrogen gas absorption method. Acrylic soft sheets prepared by calendering the same are also provided. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to acrylic polymer fine particles having a processability and texture equivalent to that of soft polyvinyl chloride and capable of providing a soft molded product containing no halogen polymer, and a molded product obtained therefrom.

Molding materials made of soft resin have been used in various industrial fields. Conventionally, the mainstream material has been so-called soft polyvinyl chloride obtained by softening polyvinyl chloride with a plasticizer. There is a demand for an alternative from polyvinyl chloride resin to a non-halogen resin, and the development of an alternative material is urgently required.
There have been many reports on the development of materials that do not use plasticizers (olefin-based elastomers, urethane-based elastomers, styrene-based elastomers, acrylic elastomers, etc.) as candidates for such alternative materials. Can not be freely adjusted, variations in the texture and hardness of the molded product will be limited. In addition, there are restrictions on control of melt viscosity and melt tension. Therefore, in order to obtain the same texture as soft polyvinyl chloride and to obtain the same texture, a material whose characteristics can be freely controlled using a plasticizer is desired.

From such a viewpoint, an acrylic polymer that has been softened using a plasticizer has been proposed (for example, Patent Document 1). In addition, a method has been proposed in which a plasticizer is added before an acrylic polymer obtained by polymerization (emulsion polymerization) in an aqueous medium is dried and powdered, and then the polymer is recovered and dried. (Patent Document 2)
JP 2003-3033 A JP 2003-128711 A

However, in the method of Patent Document 1, there is a problem with the powder structure of the polymer, and the powder itself cannot absorb a large amount of plasticizer. Therefore, it is necessary to add a plasticizer at the time of melt-kneading, and a wet powder compound containing a plasticizer cannot be prepared in advance as in the case of processing soft polyvinyl chloride. In addition, since the amount of plasticizer that can be absorbed by the polymer is extremely small, the amount of plasticizer that can be added is only about 10 parts by mass with respect to 100 parts by mass of the polymer, and sufficient softening cannot be achieved. There was a problem.
Further, in the method of Patent Document 2, it is possible to add a larger amount of plasticizer than in Patent Document 1, but any kind and amount of plasticizer can be blended according to the target product. However, there is a limit that only a compound containing a predetermined type and amount of plasticizer can be provided.

As described above, acrylic soft molding materials that are softened using conventional plasticizers can absorb only a very small amount of plasticizer during compounding, and plastic that provides sufficient flexibility. At present, it is impossible to obtain a compound containing an agent.
In addition, as shown in the above-mentioned patent document, there are examples in which calendering is possible when the amount of plasticizer is small, but in a high plasticizer blending ratio as intended by the present invention, calendering is possible. At present, it has not been possible to realize a polymer capable of satisfying processing suitability such as processing and mechanical strength of a molded product.
That is, the present invention provides an acrylic polymer for soft molding that is softened using a plasticizer. (1) To provide an acrylic polymer having high plasticizer absorbency; (2) In a high plasticizer content The present invention has been made for the purpose of providing acrylic polymer fine particles for soft molding capable of having good processability and (3) having good mechanical strength even at a high plasticizer content. .

The gist of the present invention is that it contains a polymer component (P1) having a mass average molecular weight of 400,000 or more plasticized by diisononyl phthalate, the oil absorption measured by linseed oil is 0.4 ml / g or more, and nitrogen gas The specific surface area measured by the adsorption method is in the acrylic polymer fine particles for soft molding having a range of 8 to 30 m ² / g.
The gist of the present invention resides in a soft acrylic resin composition obtained by melt-kneading the above-mentioned acrylic polymer fine particles for soft molding and a plasticizer.
Further, the gist of the present invention resides in an acrylic soft sheet obtained by calendering the soft acrylic resin composition.

  According to the acrylic polymer fine particles for soft molding of the present invention, the plasticizer absorbability when blended with a plasticizer is extremely excellent, and a powdery compound can be easily obtained. Thereby, it becomes easy to divert the processing equipment for soft polyvinyl chloride which has been widely used so far, and the workability is also improved. Moreover, it becomes possible to increase the compounding quantity of a plasticizer and to give the molded article excellent in a softness | flexibility. Furthermore, even when the amount of the plasticizer is large, it maintains a good mechanical strength and has a good suitability in processing such as calendering.

Hereinafter, the present invention will be described in detail.
When acrylic polymer fine particles (hereinafter simply referred to as “fine particles”) are softened and molded using a plasticizer, it is necessary to uniformly mix the plasticizer and the fine particles in advance and uniformly supply them to the processing machine. Therefore, the shape of the fine particles needs to be a powder that absorbs the liquid plasticizer well and is easy to be charged from a hopper or the like (hereinafter referred to as a wet powder). That is, the fine particles need to be fine particles having a high oil absorption ability. As an index of oil absorption, oil absorption by linseed oil (JIS K-5101) can be used, and its range needs to be 0.4 ml / g or more.
When the oil absorption amount of the fine particles is smaller than this, even if the plasticizer is blended, it is not sufficiently absorbed and becomes a sol or mamaco.

On the other hand, a fine particle composition obtained by blending polymer fine particles and a plasticizer needs to maintain good powder properties without blocking even when stored in that state for a long time. For that purpose, it is necessary to keep the glass transition temperature of the polymer sufficiently high without being softened immediately by simply blending the polymer fine particles and the plasticizer. This requires that the rate at which the polymer is plasticized by the plasticizer is sufficiently slow (at storage temperature).
The plasticization rate can be controlled by the contact area between the polymer and the plasticizer. The specific surface area can be used as an indicator of the contact area, and the range needs to be 30 m ² / g or less. When the specific surface area exceeds 30 m ² / g, the contact area with the plasticizer increases too much, and the plasticizer begins to plasticize the polymer during storage, the glass transition temperature of the polymer fine particles decreases, and blocking occurs. End up. On the other hand, when the specific surface area is less than 8 m ² / g, the amount of oil absorption increases, which causes a problem of becoming a sol or mamaco.

  The fine particles used in the present invention function as a polymer gel that favorably holds a plasticizer, thereby imparting flexibility to a molded product. In order to hold the plasticizer well, it is necessary to have good compatibility with the plasticizer and to have some degree of entanglement. In order to sufficiently exhibit the mechanical strength of the molded product, the molecular weight of the acrylic polymer constituting the fine particles is preferably higher than a certain level. From the above viewpoint, the acrylic polymer needs to contain a polymer component (P1) having a mass average molecular weight of 400,000 or more. When the polymer component (P1) having a mass average molecular weight of 400,000 or more is not contained, the mechanical strength tends to be slightly lowered, and particularly the strength at the tensile test is lowered.

Examples of the polymer that can be plasticized with diisononyl phthalate include acrylic polymers in which an alkyl (meth) acrylate having 4 or more carbon atoms is copolymerized in an amount of 20 mol% or more, preferably 30 mol% or more. , Methyl methacrylate / n-butyl methacrylate copolymer (copolymerization ratio 70/30 to 0/100 mol%), methyl methacrylate / i-butyl methacrylate copolymer (copolymerization ratio 70/30 to 0/100 mol%), methyl Methacrylate / 2-ethylhexyl methacrylate copolymer (copolymerization ratio 80/20 to 0/100 mol%) and the like can be mentioned.
Whether the polymer can be plasticized with diisononyl phthalate is determined by measuring the glass transition temperature of the molded product obtained by melt-kneading the polymer with a plasticizer by measuring viscoelasticity, etc., and adding glass with diisononyl phthalate. This is confirmed by a decrease in temperature. For example, in the case of a methyl methacrylate / n-butyl methacrylate copolymer (copolymerization ratio 60/40 mol%), the glass transition temperature alone is about 58 ° C., but 40 parts by mass of diisononyl phthalate (100 parts by mass of polymer) The glass transition temperature of the molded product obtained by adding ()) is lowered by 40 ° C. or more, and is judged to be plasticized.

  In the polymer of the present invention, a polymer component (P2) having a mass average molecular weight of 100,000 or more and less than 400,000 is preferably used in combination. This is because when (P2) is used in combination, fluidity at the time of heating and melting is improved, and processing such as injection molding becomes easy. Unlike the case of lowering the overall molecular weight of the polymer, it is preferable to use a high molecular weight component (P1) and a low molecular weight component (P2) in combination because both mechanical strength and fluidity can be achieved.

The polymer component (P2) is preferably a polymer that is not plasticized with diisononyl phthalate. This is because a low molecular weight polymer tends to develop tackiness when it is plasticized to a plasticizer, or tends to cause blocking of a molded product. Although it is necessary to melt into a plasticizer at a high temperature for the purpose of obtaining fluidity, it is not always necessary to be plasticized when the temperature returns to room temperature. Moreover, it is preferable to contain a component that is not plasticized at room temperature because the mechanical strength of the molded product tends to be improved.
The polymer component (P1) and the polymer component (P2) may be mutually compatible or phase separated. However, when mechanical strength is important, they are completely phase separated. It is more preferable to be completely compatible or partially compatible.

The polymer fine particles of the present invention preferably contain a rubber-like polymer component (P3) having a glass transition temperature of 0 ° C. or lower. When the polymer is softened, a monomer that gives a polymer with a low glass transition temperature is copolymerized with a case where the polymer is softened by adding a plasticizer to the polymer with a high glass transition temperature (external plasticization). There is a case of softening (internal plasticization), but in the case of internal plasticization, the plasticizer hardly leaches out, which is preferable. Therefore, by including the rubber-like polymer component (P3) having a glass transition temperature of 0 ° C. or less, it is possible to reduce the amount of plasticizer necessary for obtaining the same flexibility. In order to improve the low temperature characteristics (elongation at low temperature, flexibility, etc.) of the molded product, it is preferable to use a rubbery polymer having a low glass transition temperature.
The content of the rubber-like polymer is 60% by mass or less, preferably 40% by mass or less, based on the total polymer. This is because as the content of the rubbery polymer increases, the mechanical strength (particularly tear strength) of the molded product tends to decrease.

  The method for producing the polymer fine particles of the present invention is not particularly limited, and examples of the polymerization method include an emulsion polymerization method, a soap-free polymerization method, a suspension polymerization method, a fine suspension polymerization method, and a dispersion polymerization method. The powdering method includes a coagulation method or a spray drying method. In order to realize the oil absorption and specific surface area required in the present invention, a spray that can control the powder structure in a porous state. A dry method is preferred.

As a method for producing the polymer fine particles of the present invention, it is preferable to produce an acrylic polymer emulsion having a particle diameter of less than 500 nm by a technique such as emulsion polymerization, and then spray-dry it to obtain a powder. If the spray drying temperature conditions are the same, the specific surface area tends to decrease if the particle size of the emulsion is large. If the particle diameters of the emulsions are the same, the specific surface area tends to decrease because the degree of thermal fusion between the particles increases when the spray drying temperature is increased.
When the particle diameter of the emulsion is 500 nm or more, it is difficult to realize the specific surface area and oil absorption required in the present invention even if the spray drying conditions are changed.

When the polymer fine particles of the present invention are produced, emulsion polymerization in an aqueous medium is recommended, and the emulsifier used at that time is preferably a polymerizable emulsifier. The polymerizable emulsifier is generally an emulsifier having a carbon-carbon double bond capable of radical polymerization in the molecule, and examples thereof include an emulsifier containing a methacryloyl group, an acryloyl group, a vinyl group, and the like. Since the emulsifier is fixed to the polymer by using the polymerizable emulsifier, the possibility that the emulsifier is liberated at the time of processing or the like and the performance is lowered is reduced. For example, the phenomenon that part of the emulsifier separates during calendering and gradually accumulates on the metal roll (plate-out) can be suppressed, or whitening when the molded product is subjected to a water resistance test or a heat resistance test, etc. It becomes possible to suppress deterioration of physical properties.
The type of emulsifier (anionic, nonionic, cationic) is not particularly limited.

The particle structure of the acrylic polymer of the present invention is not particularly limited. The polymer components (P1) to (P3) may exist in a mixed state of independent and separate particles, or may exist with some structure inside a single particle. An example having a structure inside the particle is preferably a core-shell structure (multistage structure). For example, it is possible to have the polymer component (P1) as a core and the polymer component (P2) as a shell. In addition, a rubbery polymer component (P3) is laminated as the first layer, a high molecular weight polymer component (P1) as the second layer, and a low molecular weight polymer component (P2) as the third layer. A multi-stage particle is possible.
In addition, when the particle structure is a core-shell or multi-stage, it has long been known to provide such a particle structure by sequentially dropping a monomer mixture that is clearly estimated to give each polymer component as a production method. It is.

Examples of main monomers that give the acrylic polymer of the present invention are listed below: methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (Meth) acrylates, hexyl (meth) acrylates, 2-ethylhexyl (meth) acrylates, linear alkyl alcohol (meth) acrylates such as octyl (meth) acrylate, or cyclic alkyl alcohols such as cyclohexyl (meth) acrylate (Meth) acrylates.
When the rubber-like polymer component is contained, for example, the following monomers can be used as the crosslinking agent. (Poly) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl methacrylate and the like.
In addition, as copolymerization components other than acrylic monomers, for example, styrene for the purpose of adjusting the refractive index, silicone-modified acrylates for the purpose of imparting low-temperature properties, and the like can be arbitrarily copolymerized. .

The polymer fine particles of the present invention can be softened by mixing with an appropriate plasticizer and used for molded products. Examples of available plasticizers include dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, alkyl benzyl phthalates such as butyl benzyl phthalate, alkyl phthalates Aryl, dibenzyl phthalate, diaryl phthalate, triaryl phosphate such as tricresyl phosphate, trialkyl phosphate, alkylaryl phosphate, adipic acid ester, ether, polyester, large epoxidation Soybean oils such as soybean oil and others can be widely used, but are not limited thereto.
The number of added plasticizers is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, with respect to 100 parts by mass of the acrylic polymer in order to impart sufficient flexibility to the acrylic polymer. It is. In consideration of blocking of the molded product and suppression of bleed out of the plasticizer over time, it is preferably 120 parts by mass or less, more preferably 80 parts by mass or less, with respect to 100 parts by mass of the acrylic polymer. It is.

  The method of mixing the polymer fine particles and the plasticizer is not particularly limited, and can be mixed at the same time during processing, or can be pre-mixed prior to processing, but the amount of plasticizer is large It is easier to work with mixing in advance. As a method for mixing in advance, it can be handled by the same equipment and method as in the case of soft vinyl chloride, and for example, a Henschel mixer or a Banbury mixer can be used.

  In the present invention, if necessary, further fillers such as calcium carbonate, aluminum hydroxide, pearlite, clay, colloidal silica, mica powder, quartz sand, diatomaceous earth, kaolin, talc, bentonite, glass powder, aluminum oxide, fly ash, shirasu balloon, etc. May be blended. The purpose, type, amount, etc. of the filler are arbitrary. Furthermore, if necessary, pigments such as titanium oxide and carbon black, further diluents such as mineral turpentes and mineral spirits, further antifoaming agents, antifungal agents, deodorants, antibacterial agents, stabilizers, processing aids, interfaces Activators, lubricants, ultraviolet absorbers, fragrances, foaming agents, leveling agents, adhesives, matting agents, and the like can be freely blended.

  Although the processing method of the polymer composition for soft molding of this invention is not specifically limited, It can shape | mold by the processing method similar to soft vinyl chloride. For example, it can be molded by various conventionally known molding methods such as calendar molding, injection molding, T-die extrusion molding, profile extrusion molding, blow molding, vacuum molding, inflation molding, etc., but calendar molding is particularly preferable. It is.

  The use of the resin composition for a soft molding material of the present invention is not particularly limited, and can be widely applied to fields where conventional soft vinyl chloride resins have been used. Preferably in the leather field obtained by calendering, specifically for agricultural films, for building materials such as wallpaper and door materials, for furniture such as sofas and chairs, for clothes, for sundries, for bulletin boards, notebooks, etc. For binding, for automobile interiors, etc.

[Preparation of polymer emulsion (E1)]
A 300 ml four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel, and condenser tube is 80.0 g of pure water and sodium dioctylsulfosuccinate as an initial emulsifier (trade name “Perex” manufactured by Kao Corporation) 0.10 g of O-TP ") was added, and nitrogen gas was sufficiently aerated for 30 minutes while stirring at 200 rpm to replace dissolved oxygen in pure water. After stopping the nitrogen gas flow, 1/10 amount of a monomer mixture (51.4 g of methyl methacrylate, 48.6 g of n-butyl methacrylate) was added, and the temperature was raised to 80 ° C. After the internal temperature was stabilized at 80 ° C., 0.10 g of potassium persulfate dissolved in 5.0 g of pure water was added at once, and the formation of seed particles by soap-free polymerization was confirmed by confirming the exothermic peak.
Subsequently, 0.50 g of sodium dioctylsulfosuccinate (trade name “Perex O-TP”, manufactured by Kao Corporation) as an emulsifier is dissolved in the remainder (9/10 amount) of the monomer mixture, and 50.0 g of pure water is further added. In addition, the whole was forcibly emulsified using a homodisper to obtain a stable monomer emulsion. The monomer emulsion was dropped into the flask at a rate of 30 g / hr for polymerization. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of the dropwise addition, the mixture was continuously stirred at 80 ° C. for 60 minutes, and then cooled to room temperature to obtain a polymer emulsion (E1).

[Preparation of polymer emulsions (E2) to (E7)]
Similarly to the preparation of the polymer emulsion (E1), polymer emulsions (E2) to (E7) were prepared. However, the amount of the initial emulsifier, the amount of the polymerization initiator, the composition of the monomer mixture, and the amount of the chain transfer agent used by being dissolved therein were changed. The list is shown in Table 1.

表中の略号は下記の通り。
ＭＭＡ：メチルメタクリレート
ｎＢＭＡ：ｎ−ブチルメタクリレート
初期乳化剤：ジオクチルスルホコハク酸ナトリウム
連鎖移動剤：ｎ−オクタンチオール
開始剤：過硫酸カリウム

Abbreviations in the table are as follows.
MMA: methyl methacrylate nBMA: n-butyl methacrylate initial emulsifier: sodium dioctyl sulfosuccinate chain transfer agent: n-octanethiol initiator: potassium persulfate

[Preparation of polymer emulsion (E8)]
Into a 300 ml four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel, and cooling tube, put 80.0 g of pure water, 3.3 g of methyl methacrylate, and 2.5 g of n-butyl methacrylate, and at 200 rpm. While stirring, nitrogen gas was sufficiently aerated for 30 minutes to replace dissolved oxygen in pure water. After stopping the nitrogen gas flow, the temperature was raised to 80 ° C., 0.05 g of potassium persulfate dissolved in 5.0 g of pure water was added at once, and the exothermic peak was confirmed to confirm the seed particles by soap-free polymerization. Formation was confirmed.
Subsequently, the first monomer emulsion (methyl methacrylate 3.9 g, n-butyl acrylate 12.5 g, styrene 3.0 g, ethylene glycol dimethacrylate 0.67 g, azo radical polymerization initiator V-65 (Wako Pure Chemical Industries, Ltd.) ) 0.20 g, dioctyl sodium sulfosuccinate 0.20 g and pure water 10.0 g) was forcibly emulsified and added dropwise at a rate of 30 g / hr for polymerization. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued at 80 ° C. for 30 minutes.
Subsequently, a second monomer emulsion (a solution obtained by forcibly emulsifying 22.7 g of methyl methacrylate, 17.3 g of n-butyl methacrylate, 0.10 g of sodium dioctyl sulfosuccinate and 20.0 g of pure water) was dropped at a rate of 30 g / hr. Polymerization was carried out. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued at 80 ° C. for 30 minutes.
Subsequently, a third monomer emulsion (a solution obtained by forcibly emulsifying 38.9 g of methyl methacrylate, 1.1 g of n-butyl acrylate, 0.08 g of n-octyl mercaptan, 0.20 g of sodium dioctyl sulfosuccinate, and 20.0 g of pure water) Was added dropwise at a rate of 30 g / hr for polymerization. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued for 60 minutes at 80 ° C. to obtain a polymer emulsion composed of primary particles having a multilayer structure.

[Preparation of polymer emulsion (E9)]
Into a 300 ml four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel, and cooling tube, put 80.0 g of pure water, 3.3 g of methyl methacrylate, and 2.5 g of n-butyl methacrylate, and at 200 rpm. While stirring, nitrogen gas was sufficiently aerated for 30 minutes to replace dissolved oxygen in pure water. After stopping the nitrogen gas flow, the temperature was raised to 80 ° C., 0.05 g of potassium persulfate dissolved in 5.0 g of pure water was added at once, and the exothermic peak was confirmed to confirm the seed particles by soap-free polymerization. Formation was confirmed.
Subsequently, the first monomer emulsion (methyl methacrylate 3.9 g, n-butyl acrylate 12.5 g, styrene 3.0 g, ethylene glycol dimethacrylate 0.67 g, azo radical polymerization initiator V-65 (Wako Pure Chemical Industries, Ltd.) ) 0.20 g, dioctyl sodium sulfosuccinate 0.20 g and pure water 10.0 g) was forcibly emulsified and added dropwise at a rate of 30 g / hr for polymerization. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued at 80 ° C. for 30 minutes.
Subsequently, a second monomer emulsion (a solution obtained by forcibly emulsifying 22.7 g of methyl methacrylate, 17.3 g of n-butyl methacrylate, 0.10 g of sodium dioctyl sulfosuccinate and 20.0 g of pure water) was dropped at a rate of 30 g / hr. Polymerization was carried out. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued at 80 ° C. for 30 minutes.
Subsequently, a third monomer emulsion (a solution obtained by forcibly emulsifying 38.9 g of methyl methacrylate, 1.1 g of n-butyl acrylate, 0.04 g of n-octyl mercaptan, 0.20 g of sodium dioctyl sulfosuccinate, and 20.0 g of pure water) Was added dropwise at a rate of 30 g / hr for polymerization. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued for 60 minutes at 80 ° C. to obtain a polymer emulsion composed of primary particles having a multilayer structure.

[Preparation of polymer emulsion (E10)]
Into a 300 ml four-necked flask equipped with a thermometer, nitrogen gas inlet tube, stirring rod, dropping funnel, and cooling tube, put 80.0 g of pure water, 3.3 g of methyl methacrylate, and 2.5 g of n-butyl methacrylate, and at 200 rpm. While stirring, nitrogen gas was sufficiently aerated for 30 minutes to replace dissolved oxygen in pure water. After stopping the nitrogen gas flow, the temperature was raised to 80 ° C., 0.05 g of potassium persulfate dissolved in 5.0 g of pure water was added at once, and the exothermic peak was confirmed to confirm the seed particles by soap-free polymerization. Formation was confirmed.
Subsequently, the first monomer emulsion (methyl methacrylate 3.9 g, n-butyl acrylate 12.5 g, styrene 3.0 g, ethylene glycol dimethacrylate 0.67 g, azo radical polymerization initiator V-65 (Wako Pure Chemical Industries, Ltd.) ) 0.20 g, a reactive emulsifier (trade name “Latemul S180” manufactured by Kao Corporation), 0.20 g, and a solution obtained by forcibly emulsifying 10.0 g of pure water) were added dropwise at a rate of 30 g / hr for polymerization. went. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued at 80 ° C. for 30 minutes.
Subsequently, the second monomer emulsion (methyl methacrylate 22.7 g, n-butyl methacrylate 17.3 g, reactive emulsifier (trade name “Latemul S180” manufactured by Kao Corporation), 0.10 g, and pure water 20.0 g were forced. The emulsified liquid) was added dropwise at a rate of 30 g / hr for polymerization. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued at 80 ° C. for 30 minutes.
Subsequently, the third monomer emulsion (methyl methacrylate 38.9 g, n-butyl acrylate 1.1 g, n-octyl mercaptan 0.08 g, reactive emulsifier (trade name “Latemul S180” manufactured by Kao Corporation) 0.20 g, A solution obtained by forcibly emulsifying 20.0 g of pure water) was dropped at a rate of 30 g / hr to perform polymerization. During the polymerization, the temperature of the hot water bath was controlled so that the internal temperature was 80 ° C. After completion of dropping, stirring was continued for 60 minutes at 80 ° C. to obtain a polymer emulsion composed of primary particles having a multilayer structure.

[Preparation of polymer fine particles (A1) to (A11)]
The obtained polymer emulsion was filtered with a # 100 mesh nylon filter cloth, and then spray-dried using a spray dryer (Okawara Koki Co., Ltd., L-8 type) to form a powder, and polymer fine particles (A1) to (A11) was obtained.
The atomizer type of the spray dryer was a rotating disk type, and the rotation speed was 22,000 rpm. Table 2 shows operating conditions of the raw material emulsion and the spray dryer used at that time. Here, “inlet temperature” means the temperature of hot air entering the drying chamber of the spray dryer, and “outlet temperature” means the temperature near the outlet of the drying chamber of the spray dryer.
The obtained fine particles are shown in Table 2 together with the results of measurement of specific surface area, oil absorption, presence / absence of plasticization by DINP, and molecular weight.

[Specific surface area measurement method]
The surface area of the polymer fine particles was measured using a nitrogen adsorption surface area measuring device (manufactured by Horiba, Ltd., SA-6200), and the specific surface area (unit: m2 / g) per 1 g of the polymer fine particles was calculated.
[Oil absorption measurement method]
The oil absorption (unit: ml / g) of the polymer fine particles was measured by the method described in JIS K-5101.
[Measurement method of molecular weight of polymer]
The molecular weight of the polymer fine particles obtained was measured by gel permeation chromatography (GPC) for the chloroform soluble matter of the polymer. When two or more molecular weight peaks were detected, a numerical value was described for each peak.
In the present specification, unless otherwise specified, the mass average molecular weight is indicated.
[Presence or absence of plasticization by DINP]
100 parts by mass of the polymer and 40 parts by mass of diisononyl phthalate were melt-kneaded, and the glass transition temperature of the obtained molded product was measured by viscoelasticity measurement, and it was judged whether or not a decrease in the glass transition temperature was observed.

[Example 1]
Polymer fine particles (A1) 100 g, plasticizer diisononyl phthalate (trade name “Monocizer DINP”, Dainippon Ink & Chemicals, Inc.) 40.0 g, stabilizer (trade name “ADK STAB AO-60”, Asahi Denka Kogyo ( Ltd.) 0.50 g, a stabilizer (trade name “Adeka Stub 2662”, Asahi Denka Kogyo Co., Ltd.) 0.10 g, and weighed at 40 ° C. using a lab plast mill (Toyo Seiki Co., Ltd.). Were blended to prepare a powdery compound. The obtained powdery compound was melt-kneaded using a small twin screw extruder and then pelletized (extruding conditions were barrel temperature 180 ° C., die temperature 160 ° C., screw rotation speed 100 rpm).
A press sheet was prepared using the obtained pellets, and a tensile test and a tear test using a Tensilon tester were performed by the method described later. Moreover, the melt flow rate (MFR) was measured using the obtained pellet.
Table 3 shows the formulation and Table 4 shows the evaluation results.
Further, 100 g of polymer fine particles were put into a lab plast mill (manufactured by Toyo Seiki Co., Ltd., using P-200 type planetary mixer), and a plasticizer (diisononyl phthalate) was slowly injected while stirring at 40 rpm at 40 ° C. After the injection was completed, stirring was continued for another 2 minutes, and the following wet powdering was evaluated.
○: The plasticizer is absorbed well and a powdery compound can be obtained. ×: The powdery compound cannot be obtained because it becomes sol or mako, and the obtained wet powder composition is used. The blocking resistance was evaluated by the method described later.
Table 4 shows the obtained results.

表中の略号
可塑剤：ジイソノニルフタレート
安定剤１：旭電化工業（株）、商品名「アデカスタブＡＯ-６０」
安定剤２：旭電化工業（株）、商品名「アデカスタブ２６６２」

Abbreviations in Table: Plasticizer: Diisononyl phthalate stabilizer 1: Asahi Denka Kogyo Co., Ltd., trade name “ADK STAB AO-60”
Stabilizer 2: Asahi Denka Kogyo Co., Ltd., trade name “ADK STAB 2662”

[Measurement of MFR]
The resulting pellets were measured for melt flow rate (MFR) using a melt indexer (TAKARA, L244). The measurement temperature was 180 ° C. and the load was 10 kg. (Unit: g / 10 minutes)
◎: 10 or more ○: 1 or more and less than 10 ×: less than 1 [tensile test]
The obtained pellets were melted and pressed using a 37-ton press (manufactured by Oji Machinery Co., Ltd.) and a 5 mm-thick flat plate mold (press machine temperature: upper stage: 180 ° C., lower stage: 180 ° C., 5 MPa × 5 minutes). Immediately after that, it was cooled with a 100 ton press (manufactured by Shoji Steel Co., Ltd.) (water cooling, 5 MPa × 3 minutes) to prepare a press sheet. The flat plate mold was provided with a 1 mm spacer.
The obtained press sheet was cut into a dumbbell shape No. 2 type described in JIS K-6251 to obtain a test piece, and the breaking strength and initial elastic modulus at the time of a tensile test were measured with a Tensilon tester. The test speed was 200 mm / min, the load cell rating was 980 N, and the environmental temperature when measured was 25 ° C.
Breaking strength (unit: MPa)
○: 8 or more Δ: 2 or more and less than 8 ×: Less than 2 Initial elastic modulus (unit: MPa)
○: Less than 30 Δ: 30 or more and less than 100 ×: 100 or more [wet powder anti-blocking test]
20 g of the wet powder composition was weighed and placed in a cylindrical case having a cross-sectional area of 20 cm ² , and a weight with a load of 1 kg was placed thereon (50 g / cm ² ). In this state, it was kept in a constant temperature bath at 50 ° C. for 5 days and then returned to room temperature. After releasing the pressure, the blocking state of the powder was evaluated.
◎: When it is taken out of the container, it naturally returns to powder. ○: It can be returned to powder by kneading with fingers. ×: The powder is heat-sealed and does not return to powder.

[Examples 2-7, Comparative Examples 1-4]
Predetermined polymer fine particles and other additives were blended at the blending ratio shown in Table 3, and the same evaluation as in Example 1 was performed. The results are shown in Table 4.

[Examples 8 to 10]
Calendar workability was evaluated using the resin compositions of Examples 5-7.
As an indication of calendar workability, the bank periphery and sheet peelability with a roll tester and the presence or absence of plate-out were evaluated. The roll tester used an 8-inch test roll, and the set temperature was 180 ° C.
The results obtained are shown in Table 5.

Claims (4)

It contains a polymer component (P1) having a mass average molecular weight of 400,000 or more, which is an acrylic polymer copolymerized with 20 mol% or more of an alkyl (meth) acrylate having 4 or more carbon atoms , and the oil absorption measured with linseed oil is 0 .4ml / g or more, flexible molded having a specific surface area measured by nitrogen gas adsorption method is made by melt kneading a flexible molded body for acrylic polymer fine particles and a plasticizer in a range of 8~30m 2 / ^g Acrylic resin composition for body. Soft molded body acrylic polymer fine particles The weight average molecular weight of 100,000 or more 400,000 less of the polymer component (P2) according to claim 1 flexible molded body for acrylic resin composition, wherein the containing. Claim 1 or 2 flexible molded body for acrylic resin composition, wherein the soft molded body acrylic polymer microparticles glass transition temperature contains 0 ℃ less rubbery polymer component (P3) . Acrylic soft sheet obtained soft moldings for acrylic resin composition according to any one of claims 1 to 3 calendered.