JP2020070350A - Production method of graft copolymer, and production method of molded product - Google Patents

Abstract

To provide a production method of a graft copolymer with which transparency of a molded product using the graft copolymer is heightened and mechanical stability of a graft copolymer latex is improved, and to provide a production method of the molded product.SOLUTION: The invention relates to a production method of a graft copolymer, which includes: a first step to obtain an acrylic rubber by emulsion polymerization of 100 pts.mass of a vinyl monomer for a rubber part including 80-100 mass% of an alkyl acrylate and 0-20 mass% of an alkyl methacrylate with 0.1-5 pts.mass of a polyfunctional monomer; and a second step to obtain 100 pts.mass of the graft copolymer by emulsion graft polymerization of 20-97 pts.mass of a vinyl monomer for a graft part including 80-100 mass% of a vinyl chloride monomer with 3-80 pts.mass of the acrylic rubber obtained in the first step, and in which the average particle diameter of the graft copolymer is 100 nm or less, and a polymerization initiator used in the first step is an oil-soluble peroxide-based initiator.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a graft copolymer obtained by graft-polymerizing vinyl chloride on an acrylic rubber, and a method for producing a molded article using the graft polymer obtained by the production method.

  By using a graft copolymer in which vinyl chloride is graft-polymerized on acrylic rubber, impact resistance and softness of the molded product can be enhanced. On the other hand, when used in a transparent article, the graft polymer is preferably produced by emulsion polymerization in order to reduce the average particle size and increase the transparency. For example, in Patent Documents 1 and 2, after a graft base is polymerized by emulsion polymerization (also referred to as emulsion polymerization), a vinyl chloride graft is obtained by grafting a monomer constituting a graft portion to the graft base by emulsion polymerization. It has been proposed to make polymers.

Japanese Patent Publication No. 2016-506984 Japanese Patent Publication No. 2016-510074

  However, the inventors of the present application have found that the mechanical stability of the graft copolymer latex is lowered when a water-soluble peroxide is used as an initiator in the graft-based emulsion polymerization as described in Citations 1 and 2. Found.

  The present invention, in order to solve the problems described above, while increasing the transparency of the molded body using the graft copolymer, a method for producing a graft copolymer having improved mechanical stability of the graft copolymer latex, And a method for manufacturing a molded body.

  The present invention relates to 100 parts by mass of a vinyl monomer for a rubber part containing 80% by mass or more and 100% by mass or less of alkyl acrylate, 0% by mass or more and 20% by mass or less of alkyl methacrylate, and 0% by mass or more and 4% by mass or less of other vinyl monomers. A first step of emulsion polymerizing 0.1 to 5 parts by mass of a polyfunctional monomer to obtain an acrylic rubber, and 3 to 80 parts by mass of the acrylic rubber obtained in the first step. In addition, 20 parts by mass or more and 97 parts by mass or less of a vinyl monomer for a graft part containing 80% by mass or more and 100% by mass or less of a vinyl chloride monomer and 0% by mass or more and 20% by mass or less of another vinyl monomer is graft-polymerized by emulsion polymerization. A method for producing a graft copolymer, the method comprising the step of obtaining 100 parts by weight of the graft copolymer, wherein the average particle of the graft copolymer is There are at 100nm or less, the polymerization initiator used in the first step is a process for producing a graft copolymer which is a oil-soluble peroxide initiator.

  In the graft copolymer, the glass transition temperature of the rubber part is preferably 30 ° C. or lower, and the glass transition temperature of the graft part is preferably higher than 30 ° C.

  It is preferable that the acrylic rubber has a plurality of layers, the inner layer is composed of a structural unit derived from an alkyl acrylate, and the outer layer is composed of a structural unit derived from an alkyl methacrylate.

  The emulsifier used in at least one of the first step and the second step is preferably an alkenyl succinate.

  The present invention also relates to a method for producing a molded article, which is used to obtain a molded article using the graft copolymer obtained by the method for producing a graft copolymer.

  According to the method for producing a graft copolymer of the present invention, a graft copolymer capable of improving the transparency of the molded product while improving the mechanical stability of the graft copolymer latex, specifically, Marlon stability. Can be obtained. Further, a molded product having high transparency can be manufactured with high productivity by using the graft polymer obtained by the manufacturing method.

FIG. 1 is a graph showing the dynamic viscoelasticity of the graft copolymers of Example 1 and Comparative Example 1.

  The inventors of the present application, when preparing a graft copolymer by grafting a vinyl chloride monomer on an acrylic rubber obtained by emulsion polymerization by emulsion polymerization, to prepare a graft copolymer by emulsion polymerization of acrylic rubber, such as a water-soluble peroxide. When a water-soluble initiator is used, the mechanical stability of the graft copolymer latex decreases, but by using an oil-soluble peroxide initiator during emulsion polymerization of acrylic rubber, the mechanical properties of the graft copolymer latex are reduced. It was found that the stability is improved. This is because, when a water-soluble initiator such as a water-soluble peroxide is used during emulsion polymerization of acrylic rubber, the obtained acrylic rubber particles are easily hydrophilized, and thus vinyl chloride monomer is emulsion-polymerized to the acrylic rubber. In the case of grafting with, the vinyl chloride monomer is easily impregnated into the acrylic rubber particles, the coverage of the vinyl chloride monomer on the acrylic rubber particles is reduced, and therefore the mechanical stability of the graft copolymer latex is reduced. Guessed. On the other hand, when an oil-soluble peroxide-based initiator is used during emulsion polymerization of acrylic rubber, the resulting acrylic rubber particles do not become hydrophilic, and thus when vinyl chloride monomer is graft-polymerized onto the acrylic rubber, It is presumed that the vinyl chloride monomer is less likely to be impregnated into the acrylic rubber particles, the coverage of the vinyl chloride monomer on the acrylic rubber particles is high, and therefore the mechanical stability of the graft copolymer latex is improved.

(First step)
In the first step, 100 parts by mass of a vinyl monomer for a rubber part containing 80% by mass or more of an alkyl acrylate and 0.1 part by mass or more and 5 parts by mass or less of a polyfunctional monomer are emulsion-polymerized to obtain an acrylic rubber (rubber part). To get

  The alkyl acrylate is not particularly limited, but, for example, an alkyl acrylate having an alkyl group having 1 to 22 carbon atoms is used from the viewpoint of providing a polymer having excellent polymerizability, low cost, and low Tg. be able to. The alkyl may be linear or branched. Examples of the alkyl acrylate having an alkyl group having 1 to 22 carbon atoms include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate. , N-pentyl acrylate, n-hexyl acrylate, cumyl acrylate, n-heptyl acrylate, n-octyl acrylate, 2-methylheptyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate, 2-methyloctyl acrylate, 2-ethyl Heptyl acrylate, n-decyl acrylate, 2-methylnonyl acrylate, 2-ethyloctyl acrylate, dodecyl acrylate, stearyl Acrylate, behenyl acrylate, and the like. From the viewpoint of production stability, an alkyl group having 1 to 12 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms is more preferable. These can be used alone or in combination of two or more.

  The vinyl monomer for the rubber portion preferably contains 85% by mass or more of an alkyl acrylate, and 90% by mass, from the viewpoint of improving impact resistance, softness, and elongation at tensile rupture of a molded product using a graft copolymer. The above content is more preferable, the content is more preferably 95% by mass or more, and particularly preferably 100% by mass.

  The vinyl monomer for the rubber part may contain 0% by mass or more and 20% by mass or less of alkyl methacrylate, 15% by mass or less, or 10% by mass or less from the viewpoint of transparency and mechanical stability of the latex. You may contain 5 mass% or less.

  The alkyl methacrylate is not particularly limited, but, for example, an alkyl methacrylate having an alkyl group having 1 to 22 carbon atoms is used from the viewpoint of providing a polymer having excellent polymerizability, low cost, and low Tg. be able to. The alkyl may be linear or branched. Examples of the alkyl methacrylate having an alkyl group having 1 to 22 carbon atoms include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate. , N-heptylmethacrylate, n-octylmethacrylate, 2-methylheptylmethacrylate, 2-ethylhexylmethacrylate, n-nonylmethacrylate, 2-methyloctylmethacrylate, 2-ethylheptylmethacrylate, n-decylmethacrylate, 2-methylnonylmethacrylate, 2-ethyloctyl methacrylate, dodecyl methacrylate, stearyl methacrylate, behenyl methacrylate Over doors and the like. From the viewpoint of production stability, an alkyl group having 1 to 12 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms is more preferable. These can be used alone or in combination of two or more.

  The vinyl monomer for the rubber part may contain 0% by mass or more and 4% by mass or less of vinyl monomers other than alkyl acrylate and alkyl methacrylate. Here, the other vinyl monomer does not include a polyfunctional monomer described later. Examples of other vinyl monomers include vinyl halides such as vinyl chloride and vinyl bromide, vinyl cyanide derivatives such as acrylonitrile and methacrylonitrile, vinyl esters such as vinyl formate, vinyl acetate and vinyl propionate, styrene and vinyl. Toluene, aromatic vinyl derivatives such as α-methylstyrene, vinylidene chloride, vinylidene halide such as vinylidene fluoride, acrylic acid, sodium acrylate, acrylic acid such as calcium acrylate and salts thereof, β-hydroxyethyl acrylate, Acrylic acid derivatives such as phenoxyethyl acrylate, benzyl acrylate, dimethylaminoethyl acrylate, glycidyl acrylate, acrylamide, N-methyl acrylamide, methacrylic acid, sodium methacrylate, calcium methacrylate Methacrylic acid and salts thereof such as methacrylic acid, methacrylamide, β-hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, methacrylic acid derivatives such as glycidyl methacrylate, maleic anhydride, N-alkylmaleimide, malein such as N-phenylmaleimide. Examples thereof include acid derivatives. These may be used alone or in combination of two or more. Among these, aromatic vinyl derivatives are preferable from the viewpoint of transparency.

  The polyfunctional monomer may be one usually used as a crosslinking agent and / or a graft crossing agent. For example, allyl methacrylate, allyl acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl maleate, divinyl adipate, divinylbenzene, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene dimethacrylate, mono Ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethyl roll propane trimethacrylate, polyethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol diacrylate and the like can be used. These polyfunctional monomers may be used alone or in combination of two or more.

  By using 0.1 parts by mass or more and 5 parts by mass or more of the polyfunctional monomer with respect to 100 parts by mass of the vinyl monomer for the rubber part, the impact resistance, softness and transparency of the molded product using the graft copolymer can be improved. Can be good.

  In the emulsion polymerization of the first step, an oil-soluble peroxide type initiator is used as a polymerization initiator. Examples of the oil-soluble peroxide-based initiator include t-butyl hydroperoxide, cumene hydroperoxide, t-butylperoxyisopropyl carbonate, paramenthane hydroperoxide, 1,1,3,3-tetramethylbutylhydro. Examples thereof include peroxide. These oil-soluble peroxide initiators may be used alone or in combination of two or more. Among them, one or more selected from the group consisting of cumene hydroperoxide and paramenthane hydroperoxide is preferable.

  The emulsion polymerization is not particularly limited, except that an oil-soluble peroxide-based initiator is used as a polymerization initiator, and can be performed by the same method as a general emulsion polymerization method. The emulsion polymerization can be carried out, for example, by emulsion-polymerizing a vinyl monomer for a rubber part and a polyfunctional monomer in an aqueous medium in the presence of an emulsifier using an oil-soluble peroxide initiator. The vinyl monomer for the rubber portion and the polyfunctional monomer may be added by any one of batch addition, multi-stage addition, and continuous addition, or may be appropriately combined.

  The emulsifier is not particularly limited, but for example, an anionic surfactant can be used. Examples of the anionic surfactant include fatty acid salt, alkyl sulfate, alkylbenzene sulfonate, alkyl sulfosuccinate, alkenyl succinate, rosinate, polyoxyethylene lauryl sulfate, α-olefin sulfonate, alkyl. Examples thereof include ether phosphate salts. Examples of the salt include potassium salt, sodium salt, ammonium salt and the like. Among them, alkenyl succinate is preferable from the viewpoint of high compatibility with the graft copolymer and increasing the transparency of the molded product using the graft copolymer. As the alkenyl succinate, for example, those having an alkenyl group having 8 to 22 carbon atoms are preferable, and those having an alkenyl group having 10 to 18 carbon atoms are more preferable. Examples of the salt include metal salts such as alkali metal salts such as potassium salt and sodium salt, potassium salt is preferable, mono salt or di salt may be used, and di salt is preferable.

  In the present invention, it is preferable that the rubber part has a plurality of layers, the inner layer is composed of a structural unit derived from an alkyl acrylate, and the outer layer is composed of a structural unit derived from an alkyl methacrylate. In this case, it is possible to emulsion-polymerize an alkyl acrylate to obtain an inner layer composed of a structural unit derived from an alkyl acrylate, and then emulsion polymerize an alkyl methacrylate to obtain an outer layer composed of a structural unit derived from an alkyl methacrylate. .. Any of the plurality of layers is prepared by emulsion polymerization using an oil-soluble peroxide-based initiator as a polymerization initiator.

  In the latex of the rubber part, the average particle size of the rubber part is preferably 10 nm or more and less than 100 nm, more preferably 15 nm or more and 90 nm or less, and 20 nm or more and 80 nm or less from the viewpoint of transparency and impact resistance. Is more preferable. In the present invention, the average particle diameter of the rubber portion in the latex of the rubber portion is a volume-based average particle diameter, and for example, a particle diameter distribution measuring device using a dynamic light scattering method (“Nanotrac Wave manufactured by Nikkiso Co., Ltd.” ]) Can be used for measurement.

  In the latex of the rubber part, the concentration of the rubber part, that is, the concentration of the solid content is not particularly limited, but for example, from the viewpoint of increasing the charging amount, it is preferably 25% by mass or more and 50% by mass or less, and 28% by mass. % Or more and 45 mass% or less is more preferable.

(Second step)
In the second step, 20 parts by weight or more and 97 parts by weight or less of vinyl monomer for graft portion containing 80% by weight or more of vinyl chloride monomer is added to 3 parts by weight or more and 80 parts by weight or less of the acrylic rubber obtained in the first step. Grafting is carried out by emulsion polymerization to obtain 100 parts by mass of the graft copolymer.

  In the present invention, when the molded article using the graft copolymer is used in the soft field, preferably, the graft copolymer is 30 parts by mass of the acrylic rubber when the graft copolymer is 100 parts by mass. It is obtained by graft polymerizing 20 parts by mass or more and 70 parts by mass or less of vinyl monomer for graft part by emulsion polymerization to 80 parts by mass or more, and more preferably 40 parts by mass or more and 70 parts by mass or less of the acrylic rubber. And 30 parts by weight or more and 60 parts by weight or less of a vinyl monomer for a graft portion are graft-polymerized by emulsion polymerization.

  In the present invention, when the molded product using the graft copolymer is used in the hard field, preferably, the graft copolymer is 3 parts by mass of the acrylic rubber when the graft copolymer is 100 parts by mass. It is obtained by graft polymerizing more than 70 parts by mass and more than 97 parts by mass of vinyl monomer for graft part by emulsion polymerization to more than 30 parts by mass, more preferably 5 parts by mass or more and 29.9 parts by mass of the acrylic rubber. Below, 70.1 parts by mass or more and 95 parts by mass or less of a vinyl monomer for a graft part is graft-polymerized by emulsion polymerization.

  The vinyl monomer for the graft portion preferably contains vinyl chloride in an amount of 85% by mass or more, more preferably 90% by mass or more, and more preferably 95% by mass, from the viewpoint of improving the moldability of the molded product using the graft copolymer. It is more preferable to include the above, and it is particularly preferable to be 100% by mass.

  From the viewpoint of transparency and mechanical stability of the latex, the vinyl monomer for the graft part may contain 0% by mass or more and 20% by mass or less, or 15% by mass or less of other vinyl monomers in addition to the vinyl chloride monomer. The content may be 10% by mass or less, or 5% by mass or less. As the other vinyl monomer, the alkyl acrylate, alkyl methacrylate and other vinyl monomers listed as those used for the rubber portion vinyl monomer can be appropriately used.

  The emulsion polymerization is not particularly limited except that it is carried out in the presence of the rubber part (specifically, the latex of the rubber part), and it can be carried out by the same method as a general emulsion polymerization method. In the emulsion polymerization, for example, the vinyl monomer for the graft portion can be emulsion polymerized in the presence of an emulsifier using a polymerization initiator in an aqueous medium. The vinyl monomer for the graft portion may be added all at once, in multiple stages, or continuously, and may be appropriately combined.

  As the polymerization initiator, for example, an organic peroxide, an azo-based initiator, peroxodisulfate (also referred to as persulfate), aqueous hydrogen peroxide or the like can be used. Examples of the organic peroxide include t-butyl hydroperoxide, cumene hydroperoxide, t-butylperoxyisopropyl carbonate, paramenthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, Examples thereof include benzoyl peroxide and lauroyl peroxide. Examples of the azo-based initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) and 2,2′-azobis (4-methoxy-2,2). 4-dimethylvaleronitrile) and the like. Examples of peroxodisulfate include ammonium persulfate, potassium persulfate, sodium persulfate and the like. These polymerization initiators can be used alone or in combination of two or more kinds.

  The polymerization initiator can be used in combination with a reducing agent such as sodium sulfite, sodium thiosulfate, sodium hydroxymethanesulfinate, ascorbic acid, sodium ascorbate, and sodium formaldehyde sulfoxylate, if necessary. The reducing agents may be used alone or in combination of two or more.

  The organic peroxide can be used as a redox type polymerization initiator together with a redox catalyst and a reducing agent. As the redox catalyst, a transition metal complex produced by using a transition metal salt and a chelating agent in combination can be used. Examples of the transition metal salt include ferrous sulfate (II), copper (II) sulfate, and copper chloride. Examples of the chelating agent include ethylenediaminetetraacetic acid disodium salt (EDTA · 2Na), tartaric acid, and ammonia. Etc. When ferrous sulfate (II) is used as the transition metal salt and disodium ethylenediaminetetraacetate (EDTA · 2Na) is used as the chelating agent, Fe-EDTA is produced and functions as a redox catalyst.

  As the emulsifier, those enumerated as the emulsifier used for the emulsion polymerization of the rubber portion can be appropriately used. As the emulsifier, an alkenyl succinate is preferably used from the viewpoint of high compatibility with the graft copolymer and increasing the transparency of the molded product using the graft copolymer. As the alkenyl succinate, for example, those having an alkenyl group having 8 to 22 carbon atoms are preferable, and those having an alkenyl group having 10 to 18 carbon atoms are more preferable. Examples of the salt include metal salts such as alkali metal salts such as potassium salt and sodium salt, potassium salt is preferable, mono salt or di salt may be used, and di salt is preferable.

  In the step of producing the graft copolymer including the first step and the second step, from the viewpoint of polymerization stability and mechanical stability of the latex, the total mass of the vinyl monomer for the rubber portion and the vinyl monomer for the graft portion is set to When it is 100 parts by mass, that is, it is preferable to add 0.3 parts by mass or more and 8.0 parts by mass or less in total to 100 parts by mass of the graft copolymer, and 0.5 parts by mass or more and 6. It is more preferably added in an amount of 0 part by mass or less, and further preferably 1.0 part by mass or more and 4.0 parts by mass or less. When the amount of the emulsifier is 4.0 parts by mass or less, the transparency becomes better. Further, when the emulsifier is 1.0 part by mass or more, the mechanical stability becomes better. In the first step, by using an oil-soluble peroxide-based initiator as a polymerization initiator, the mechanical stability is improved even if the amount of the emulsifier is reduced, and the amount of the emulsifier is reduced to be transparent. The nature is enhanced.

  In the first step, for example, from the viewpoint of polymerization stability, it is preferable to add 0.3 parts by mass or more and 8.0 parts by mass or less of an emulsifier to 100 parts by mass of the vinyl monomer for a rubber part, and 0.5 part by mass. It is more preferable to add 1.0 part by mass or more and 6.0 parts by mass or less, and further preferably 1.0 part by mass or more and 4.0 parts by mass or less. In the second step, for example, from the viewpoint of polymerization stability and mechanical stability of the latex, an emulsifier may be added in an amount of 0.3 parts by mass or more and 8.0 parts by mass or less with respect to 100 parts by mass of the vinyl monomer for graft part. It is more preferable to add 0.5 parts by mass or more and 6.0 parts by mass or less, and further preferably 1.0 parts by mass or more and 4.0 parts by mass or less. The emulsifier may be added to the graft polymer latex after the second step, if necessary.

  In the graft copolymer latex obtained as described above, the average particle diameter of the graft copolymer is 100 nm or less, and a molded product having excellent transparency can be obtained. From the viewpoint of excellent impact resistance and transparency, the average particle size of the graft copolymer is preferably 15 nm or more and 100 nm or less, more preferably 20 nm or more and 95 nm or less, and further preferably 25 nm or more and 90 nm or less. The average particle size of the graft copolymer in the graft copolymer latex is a volume-based average particle size, and for example, a particle size distribution measuring device using a dynamic light scattering method (“Nanotrac Wave manufactured by Nikkiso Co., Ltd.” ]) Can be used for measurement.

  In the graft copolymer latex, the solid content concentration is not particularly limited, but is preferably 25% by mass or more and 50% by mass or less, and more preferably 28% by mass or more and 45% by mass or less.

  From the viewpoint of excellent mechanical stability, the graft copolymer latex, when tested by a Marlon tester according to JIS K 6392, has a ratio of the mass of the aggregate to the solid matter in the graft copolymer latex, That is, the aggregation rate is preferably 30% by mass or less, more preferably 25% by mass or less, further preferably 20% by mass or less, still more preferably 10% by mass or less, and 5% by mass. % Or less is particularly preferable.

  One or more coagulants selected from the group consisting of acids and salts are added to the graft copolymer latex to coagulate, and heat treated at a temperature of, for example, 40 ° C. or higher and 110 ° C. or lower, washed, dehydrated, and dried, A powdery graft copolymer can be obtained by sieving with a size of 1. Also, powder spray drying or the like can be used.

  The glass transition temperature of the rubber portion of the graft copolymer is 30 ° C. or lower, and the glass transition temperature of the graft portion is preferably higher than 30 ° C. The coverage of the graft part on the rubber part is high, and the mechanical stability is good. More preferably, the glass transition temperature of the rubber portion is 30 ° C. or lower, and the glass transition temperature of the graft portion is 50 ° C. or higher. In the present invention, the glass transition temperature of the rubber part and the graft part can be determined by measuring the dynamic viscoelasticity at a frequency of 1 HZ, a strain of 0.05% and a temperature rising rate of 4 ° C./min.

(Method for manufacturing molded body)
A molded product can be obtained using the graft copolymer obtained above. If necessary, various additives such as a plasticizer, a stabilizer, a lubricant, an antistatic agent, a colorant, an ultraviolet absorber, a filler, and a diluent may be added to the graft copolymer as a resin composition. Good.

  The resin composition is not particularly limited, but can be molded by any method such as calender molding method, injection molding method, and extrusion molding method to obtain a molded body.

  From the viewpoint of excellent transparency, when the molded body has a thickness of 5 mm, the haze measured according to JIS K 6714 is preferably 50% or less, more preferably 40% or less. , 30% or less is more preferable, 20% or less is still more preferable, and 10% or less is particularly preferable. It is possible to obtain a transparent molded article having excellent softness or a transparent molded article having excellent impact resistance without using a plasticizer.

  From the viewpoint of being suitably used for soft applications, when the molded body has a thickness of 1 mm, the tensile elastic modulus measured according to JIS K 6251 is preferably 5 MPa or more and 500 MPa or less, more preferably 10 MPa or more and 300 MPa or less. And more preferably 15 MPa or more and 100 MPa or less. Examples of the molded article for soft use include a calender molding method, an injection molding method, a soft film obtained by an extrusion molding method, a sheet, a plate, various molded articles, and specifically, medical bags, tubes, Typical examples are film sheets for automobile interiors, desk mats for stationery, soft materials for writing instruments, electric wire coating materials, floor materials, and various sealing materials.

  From the viewpoint of being suitably used for hard applications, the molded body preferably has a tensile elastic modulus of 500 MPa or more and 2500 MPa or less, and more preferably 550 MPa or more and 2300 MPa or less when measured in accordance with JIS K 6251 when the thickness is 1 mm. And more preferably 600 MPa or more and 2100 MPa or less. Examples of the molded article for hard use include a calender molding method, an injection molding method, a hard film obtained by an extrusion molding method, a sheet, a plate, various molded articles, and specifically, a printing film / sheet, Typical examples are automotive interior film / sheet, food / pharmaceutical film, sheet, container, architectural film, sheet, board, roofing material, wall material, window frame material, gutter material, various pipe materials / pipe material joints, etc. ..

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In the following, "parts" means "parts by mass" and "%" means "% by mass" unless otherwise specified.

  First, various measuring methods and evaluation methods will be described.

(Average particle size and particle size distribution)
The average particle size and the particle size distribution were measured on a volume basis using a particle size distribution measuring device using a dynamic light scattering method (“Nanotrac Wave-EX150” manufactured by Nikkiso Co., Ltd.).

(Glass-transition temperature)
The glass transition temperatures of the rubber portion and the graft portion were measured with a dynamic viscoelasticity measuring device (IT Measurement and Measurement Co., Ltd. “DVA-200”) at a frequency of 1 HZ, a strain of 0.05%, and a heating rate of 4 ° C./min. It was determined by measuring the dynamic viscoelasticity.

(Mechanical stability test)
According to JIS K 6392, 100 g of emulsion was used in a Marlon tester, a load of 7 kg, a rotation speed of 1000 rpm, preheating at 50 ° C. for 2 minutes, and then a test for 20 minutes. The mass of the agglomerates after the test was weighed and shown as the ratio (mass%) to the mass of the solid content in the charged emulsion, that is, the agglomeration rate (mass%). Based on the aggregation rate, the mechanical stability was evaluated according to the following criteria.
◯: The aggregation rate is 30% by mass or less, and the mechanical stability is good.
X: The agglomeration rate exceeds 30% by mass, and the mechanical stability is poor.

(Preparation of test pieces for measuring physical properties)
100 parts of vinyl chloride-based graft copolymer, 1.0 part of tin-based stabilizer ("TVS # 1360" manufactured by Nitto Kasei Co., Ltd.), and processability improver ("Kaneace PA-20" manufactured by Kaneka Corporation) 1.0 Parts, a lubricant (“Loxiol GH-4” manufactured by Emery-Oleochemicals Japan KK) 0.5 part, and a lubricant (“Loxiol G-70S” manufactured by Emery-Oleochemicals Japan KK) 0.4 part while stirring to 110 ° C. The mixture was heated and cooled to room temperature to obtain a compound (total 102.9 parts). The obtained compound was kneaded with two rolls (“8 inch mixing roll” manufactured by Nippon Roll Mfg. Co., Ltd.) at 160 ° C. for 5 minutes to prepare a sheet. Then, using a heat press machine (Kantan Metal Industry Co., Ltd., 37 ton press), it was pressed at a pressure of 100 kgf / cm ² for 15 minutes at 175 ° C., and a test plate for measuring transparency (30 mm × 40 mm × thickness). 5 mm) and a test piece for tensile test (JIS K 6251-1 type) (thickness 1 mm) were prepared.

(Measurement of haze (turbidity))
The haze (turbidity) of the transparency test plate (5 mm) was measured according to JIS K6714. Based on the haze value, the transparency was evaluated according to the following 5 grades. A rating of 1 means poor transparency.
5: Haze is 10 or less 4: Haze is 10 or more and 20 or less 3: Haze is 20 or more and 30 or less 2: Haze is 30 or more and 50 or less 1: Haze is 50 or more (measurement of tensile elastic modulus)
Using a test piece for a tensile test (thickness: 1 mm), a tensile test was performed according to JIS K 6251 to measure the tensile elastic modulus.

(Example 1)
<Polymerization of rubber part>
230 parts of water and 1.6 parts of sodium dioctylsulfosuccinate were charged into a polymerization vessel equipped with a stirrer, the temperature was raised to 60 ° C. after nitrogen replacement, and 0.0094 parts of ferrous sulfate (FeSO ₄ .7H ₂ O) and ethylenediamine tetrachloride were added. 0.0156 parts of disodium acetate (EDTA / 2Na) and 0.5 parts of sodium formaldehyde sulfoxylate are added, and then 90 parts of butyl acrylate (BA), 10 parts of methyl methacrylate (MMA), 1.2 parts of allyl methacrylate. And 0.23 parts of paramenthane hydroperoxide were continuously added over 300 minutes, and 30 minutes after the addition was completed, 0.23 parts of paramenthane hydroperoxide was added, and after 30 minutes of further polymerization, polymerization conversion Includes acrylic rubber (rubber part) with a rate of 99%, a solid content concentration of 30%, and an average particle size of 33 nm To obtain a beam portion latex (R-1).

<Polymerization of graft part>
Then, 167 parts of the rubber latex (R-1) (50 parts of solid content), 230 parts of water (including water brought in from the latex of rubber, the same applies hereinafter), 0.2 part of sodium dioctylsulfosuccinate, and sulfuric acid first 0.0012 parts of iron (FeSO ₄ .7H ₂ O), 0.0021 parts of EDTA.2Na, and 0.054 parts of sodium formaldehyde sulfoxylate were charged in a polymerization vessel equipped with a stirrer. After deoxidizing, 67 parts of vinyl chloride monomer was charged, the temperature was raised to 65 ° C., and an aqueous solution of hydrogen peroxide (0.06%) was continuously added for 135 minutes so that the hydrogen peroxide became 0.03 part. Was added. Further, an aqueous solution of dioctyl sodium sulfosuccinate (2%) was continuously added over 135 minutes so that the content of sodium dioctyl sulfosuccinate was 0.3 part. The reaction was stopped when the internal pressure dropped to 0.3 MPa. The polymerization conversion rate was 75%. Unreacted vinyl chloride is removed, vinyl chloride graft copolymer containing vinyl chloride graft copolymer having an average particle size of 49 nm, glass transition temperature of rubber portion of 10 ° C. and glass transition temperature of graft portion of 82 ° C. A combined latex (G-1) was obtained. When calculated based on the polymerization conversion rate, the vinyl chloride content was 50 parts in 100 parts of the vinyl chloride-based graft copolymer. That is, the vinyl chloride-based graft copolymer of Example 1 was composed of 50 parts of rubber part and 50 parts of graft part. 3.5 parts of sodium dioctylsulfosuccinate was further added to the obtained vinyl chloride-based graft copolymer latex (G-1), and the total amount of sodium dioctylsulfosuccinate was added to 100 parts of the vinyl chloride-based graft copolymer. A vinyl chloride-based graft copolymer latex (M-1) was prepared in an amount of 4.8 parts. Mechanical stability was evaluated using a vinyl chloride graft copolymer latex (M-1).

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (M-1) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-1). , Various physical properties were evaluated.

(Example 2)
<Polymerization of rubber part and graft part>
The rubber part and the graft part were polymerized in the same manner as in Example 1 to obtain a vinyl chloride graft copolymer latex (G-1). 1.9 parts of sodium dioctylsulfosuccinate was further added to the obtained vinyl chloride-based graft copolymer latex (G-1), and the total amount of sodium dioctylsulfosuccinate was added to 100 parts of the vinyl chloride-based graft copolymer. A vinyl chloride-based graft copolymer latex (M-2) was prepared in an amount of 3.2 parts. Mechanical stability was evaluated with a vinyl chloride-based graft copolymer latex (M-2).

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (M-2) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-2). , Various physical properties were evaluated.

(Example 3)
<Polymerization of rubber part>
230 parts of water and 3.2 parts of alkenyl succinate dipotassium (alkenyl group having 16 to 18 carbon atoms, manufactured by Kao Chemical Co., Ltd., trade name "Latemuru ASK", hereinafter also simply referred to as "ASK") 3.2 parts in a polymerization vessel with a stirrer. After charging and replacing with nitrogen, the temperature was raised to 60 ° C., and 0.0094 parts of ferrous sulfate (FeSO ₄ .7H ₂ O), 0.0156 parts of EDTA / 2Na, and 0.5 parts of sodium formaldehyde sulfoxylate were added. Then, a mixed solution of 90 parts of butyl acrylate, 1.08 part of allyl methacrylate and 0.207 part of paramenthane hydroperoxide was continuously added over 270 minutes, and after 30 minutes from the addition, 10 parts of methyl methacrylate and paramenthane hydroperoxide were added. 0.02 parts of the mixed solution was continuously added over 30 minutes, and after 60 minutes of post-polymerization Latex (R-3) containing acrylic rubber having a polymerization conversion rate of 99%, a solid content concentration of 30%, and an average particle diameter of 55 nm after addition of 0.23 part of hydroperoxide for 30 minutes. Got In the obtained rubber part latex (R-3), 100 parts of the rubber part is formed of an inner layer composed of 90 parts of butyl acrylate and an outer layer composed of 10 parts of methyl methacrylate.

<Polymerization of graft part>
Then, the rubber part latex (R-3) 222 parts (solid content 66.5 parts), water 230 parts, ferrous sulfate (FeSO ₄ .7H ₂ O) 0.0012 parts, EDTA 2Na 0.0021 parts, 0.054 parts of sodium formaldehyde sulfoxylate was placed in a polymerization vessel equipped with a stirrer. After deoxidizing, 45 parts of vinyl chloride monomer was charged, the temperature was raised to 65 ° C., and an aqueous solution (0.3%) of t-butyl hydroperoxide was added so that t-butyl hydroperoxide became 0.04 part. Added continuously over 150 minutes. The reaction was stopped when the internal pressure dropped to 0.3 MPa. The polymerization conversion rate was 75%. Unreacted vinyl chloride is removed, vinyl chloride-based graft copolymer containing vinyl chloride-based graft copolymer having an average particle size of 71 nm, a rubber transition glass transition temperature of 0 ° C. and a graft transition temperature of 80 ° C. A combined latex (G-3) was obtained. When calculated based on the polymerization conversion rate, the vinyl chloride content in 100 parts of the vinyl chloride-based graft copolymer was 33.5 parts. That is, the vinyl chloride-based graft copolymer of Example 3 was composed of 66.5 parts of rubber part and 33.5 parts of graft part. In the obtained vinyl chloride-based graft copolymer latex (G-3), the total amount of dipotassium alkenyl succinate (ASK) added was 2.1 parts based on 100 parts of the vinyl chloride-based graft copolymer. The vinyl chloride graft copolymer latex (G-3) was used to evaluate the mechanical stability.

(Post-processing)
The obtained vinyl chloride-based graft copolymer latex (G-3) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-3). , Various physical properties were evaluated.

(Example 4)
<Polymerization of rubber part and graft part>
The rubber part and the graft part were polymerized in the same manner as in Example 3 to obtain a vinyl chloride-based graft copolymer latex (G-3). 2.0 parts of dipotassium alkenyl succinate (ASK) was further post-added to the obtained vinyl chloride-based graft copolymer latex (G-3), and dipotassium alkenyl succinate (100 parts by weight of vinyl chloride-based graft copolymer ( A vinyl chloride-based graft copolymer latex (M-4) was prepared so that the total amount of ASK) added was 4.1 parts. The vinyl chloride graft copolymer latex (M-4) was used to evaluate the mechanical stability.

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (M-4) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-4). , Various physical properties were evaluated.

(Example 5)
<Polymerization of rubber part>
230 parts of water and 3.2 parts of dipotassium alkenyl succinate (ASK) were charged into a polymerization vessel equipped with a stirrer, the temperature was raised to 60 ° C. after nitrogen substitution, and 0.0094 parts of ferrous sulfate (FeSO ₄ .7H ₂ O) was added. , EDTA.2Na 0.0156 parts, sodium formaldehyde sulfoxylate 0.5 parts, and then a mixture of 100 parts butyl acrylate, 1.2 parts allyl methacrylate and 0.23 parts paramenthane hydroperoxide for 300 minutes. After 30 minutes of post-polymerization, 0.23 parts of paramenthane hydroperoxide was added, and after 30 minutes of post-polymerization, the polymerization conversion rate was 99%, the solid content concentration was 30%, and the average particle size was 55 nm. A rubber latex (R-5) containing an acrylic rubber was obtained.

<Polymerization of graft part>
Then, 206 parts of the rubber part latex (R-5) (solid content 61.8 parts), 230 parts of water, 0.0012 parts of ferrous sulfate (FeSO ₄ .7H ₂ O), 0.0021 parts of EDTA.2Na, 0.054 parts of sodium formaldehyde sulfoxylate was placed in a polymerization vessel equipped with a stirrer. After deoxidizing, 51 parts of vinyl chloride monomer was charged, the temperature was raised to 65 ° C., and an aqueous solution (0.3%) of t-butyl hydroperoxide was added so that t-butyl hydroperoxide became 0.04 part. Added continuously over 150 minutes. The reaction was stopped when the internal pressure dropped to 0.3 MPa. The polymerization conversion rate was 75%. Unreacted vinyl chloride is removed, and a vinyl chloride-based graft copolymer containing a vinyl chloride-based graft copolymer having an average particle diameter of 61 nm, a rubber transition glass transition temperature of −10 ° C. and a graft transition temperature of 78 ° C. Polymer latex (G-5) was obtained. When calculated based on the polymerization conversion rate, the vinyl chloride content was 38.2 parts in 100 parts of the vinyl chloride-based graft copolymer. That is, the vinyl chloride-based graft copolymer of Example 5 was composed of 61.2 parts of rubber part and 38.2 parts of graft part. Further, 1.3 parts of dipotassium alkenyl succinate (ASK) was post-added to the obtained vinyl chloride-based graft copolymer latex (G-5), and dipotassium alkenyl succinate (100 parts by weight of vinyl chloride-based graft copolymer) was added. A vinyl chloride-based graft copolymer latex (M-5) was prepared so that the total amount of ASK) added was 3.3 parts. The obtained vinyl chloride graft copolymer latex (M-5) was evaluated for mechanical stability.

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (M-5) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-5). , Various physical properties were evaluated.

(Example 6)
<Polymerization of rubber part and graft part>
The rubber part and the graft part were polymerized in the same manner as in Example 5 to obtain a vinyl chloride-based graft copolymer latex (G-5). 2.0 parts of dipotassium alkenyl succinate (ASK) was further post-added to the obtained vinyl chloride-based graft copolymer latex (G-5), and dipotassium alkenyl succinate (100 parts by weight of vinyl chloride-based graft copolymer) was added. A vinyl chloride-based graft copolymer latex (M-6) was prepared so that the total amount of ASK) added was 4.0 parts. The vinyl chloride graft copolymer latex (M-6) thus obtained was used to evaluate the mechanical stability.

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (M-6) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-6). , Various physical properties were evaluated.

(Example 7)
<Polymerization of rubber part>
230 parts of water and 3.6 parts of dipotassium alkenyl succinate (ASK) were placed in a polymerization vessel equipped with a stirrer, the temperature was raised to 60 ° C. after nitrogen substitution, and 0.0094 parts of ferrous sulfate (FeSO ₄ .7H ₂ O) was added. , EDTA.2Na 0.0156 parts, sodium formaldehyde sulfoxylate 0.5 parts, and then 90 parts butyl acrylate, 10 parts methyl methacrylate, 1.2 parts allyl methacrylate and 0.23 parts paramenthane hydroperoxide. The mixture was continuously added over 300 minutes and after 30 minutes of post-polymerization, 0.23 parts of paramenthane hydroperoxide was added, and after further 30 minutes of post-polymerization, the polymerization conversion rate was 99%, the solid content concentration was 30%, A rubber part latex (R-7) containing an acrylic rubber having an average particle diameter of 56 nm was obtained.

<Polymerization of graft part>
Then, 212 parts of the rubber part latex (R-7) (solid content 63.5 parts), 230 parts of water, 1.6 parts of dipotassium alkenylsuccinate (ASK), ferrous sulfate (FeSO ₄ .7H ₂ O) 0.0012 parts, EDTA.2Na 0.0021 parts, and sodium formaldehyde sulfoxylate 0.054 parts were placed in a polymerization vessel equipped with a stirrer. After deoxidizing, 49 parts of vinyl chloride monomer was charged, the temperature was raised to 65 ° C., and an aqueous solution of t-butyl hydroperoxide (0.3%) was added so that t-butyl hydroperoxide became 0.04 part. Added continuously over 150 minutes. The reaction was stopped when the internal pressure dropped to 0.3 MPa. The polymerization conversion rate was 75%. Unreacted vinyl chloride is removed, and a vinyl chloride graft copolymer containing a vinyl chloride graft copolymer having an average particle diameter of 60 nm, a rubber transition glass transition temperature of 10 ° C., and a graft transition glass transition temperature of 80 ° C. A combined latex (G-7) was obtained. When calculated based on the polymerization conversion rate, the vinyl chloride content was 36.5 parts in 100 parts of the vinyl chloride-based graft copolymer. That is, the vinyl chloride graft copolymer of Example 7 was composed of 63.5 parts of rubber part and 36.5 parts of graft part. Further, 0.4 parts of dipotassium alkenylsuccinate (ASK) was post-added to the obtained vinyl chloride-based graft copolymer latex (G-7), and dipotassium alkenylsuccinate (100 parts by weight of vinyl chloride-based graft copolymer) was added. A vinyl chloride-based graft copolymer latex (M-7) was prepared so that the total amount of ASK) added was 4.3 parts. The obtained vinyl chloride-based graft copolymer latex (M-7) was evaluated for mechanical stability.

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (M-7) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-7). , Various physical properties were evaluated.

(Example 8)
<Polymerization of rubber part>
Except that the emulsifier used in Example 7 was changed to 6.5 parts of alkenyl succinate dipotassium (alkenyl group having 12 to 14 carbon atoms, manufactured by Kao Chemical Co., Ltd., trade name "Latemul DSK", hereinafter also simply referred to as DSK). In the same manner as in Example 7, a rubber part latex (R-8) containing an acrylic rubber having a polymerization conversion rate of 99%, a solid content concentration of 30% and an average particle diameter of 56 nm was obtained.

(Polymerization of graft part)
Then, using the rubber part latex (R-8) 219 parts (solid content 65.7 parts), the graft part was polymerized in the same manner as in Example 7 except that an emulsifier was not added, and the average particle size was 60 nm. A vinyl chloride graft copolymer latex (G-8) containing a vinyl chloride graft copolymer having a glass transition temperature of 10 ° C. in the rubber portion and a glass transition temperature of 80 ° C. in the graft portion was obtained. The polymerization conversion rate was 75%. When calculated based on the polymerization conversion rate, the vinyl chloride content was 34.3 parts in 100 parts of the vinyl chloride-based graft copolymer. That is, the vinyl chloride-based graft copolymer of Example 8 was composed of 65.7 parts of rubber part and 34.3 parts of graft part. Further, 0.7 part of dipotassium alkenyl succinate (DSK) was further added to the obtained vinyl chloride-based graft copolymer latex (G-8), and dipotassium alkenyl succinate (100 parts by weight of vinyl chloride-based graft copolymer ( A vinyl chloride-based graft copolymer latex (M-8) was prepared so that the total amount of DSK) added was 5.0 parts. The obtained vinyl chloride-based graft copolymer latex (M-8) was evaluated for mechanical stability.

(Post-processing)
The obtained vinyl chloride-based graft copolymer latex (M-8) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (P-8). , Various physical properties were evaluated.

(Example 9)
<Polymerization of rubber part>
230 parts of water and 1.3 parts of sodium dioctylsulfosuccinate were charged into a polymerization vessel equipped with a stirrer, the temperature was raised to 60 ° C. after purging with nitrogen, and 0.0094 parts of ferrous sulfate (FeSO ₄ .7H ₂ O), EDTA. 2Na (0.0156 parts) and sodium formaldehyde sulfoxylate (0.5 parts) were added, and then 300 parts of a mixed solution of butyl acrylate (90 parts), methyl methacrylate (10 parts), allyl methacrylate (1.2 parts) and cumene hydroperoxide (0.20 parts) was added. Continuously added over a period of 30 minutes, 0.20 part of cumene hydroperoxide was added 30 minutes after the end of the addition, and after further polymerization for 30 minutes, the conversion of polymerization was 99%, the solid content concentration was 30%, and the average particle size was 40 nm. A rubber latex (R-9) containing an acrylic rubber was obtained.

<Polymerization of graft part>
Then, the rubber part latex (R-9) 95 parts (solid content 28.6 parts), water 230 parts, dioctyl sodium sulfosuccinate 0.2 part, ferrous sulfate (FeSO ₄ .7H ₂ O) 0.0012 Parts, EDTA.2Na 0.0021 parts, and sodium formaldehyde sulfoxylate 0.054 parts were charged in a polymerization container equipped with a stirrer. After deoxidizing, 95 parts of vinyl chloride monomer was charged, the temperature was raised to 65 ° C., and an aqueous solution of hydrogen peroxide (0.06%) was continuously added for 135 minutes so that the hydrogen peroxide became 0.03 part. Was added. Further, an aqueous solution of dioctyl sodium sulfosuccinate (2%) was continuously added over 135 minutes so that the content of sodium dioctyl sulfosuccinate was 0.3 part. The reaction was stopped when the internal pressure dropped to 0.3 MPa. The polymerization conversion rate was 75%. Unreacted vinyl chloride is removed, and a vinyl chloride graft copolymer containing a vinyl chloride graft copolymer having an average particle diameter of 60 nm, a rubber transition glass transition temperature of 10 ° C., and a graft transition temperature of 82 ° C. A combined latex (G-9) was obtained. When calculated based on the polymerization conversion rate, the vinyl chloride content was 71.4 parts in 100 parts of the vinyl chloride-based graft copolymer. That is, the vinyl chloride-based graft copolymer of Example 9 was composed of a rubber portion of 28.6 parts and a graft portion of 71.4 parts. In the obtained vinyl chloride-based graft copolymer latex (G-9), the total amount of sodium dioctylsulfosuccinate added to 100 parts of the vinyl chloride-based graft copolymer was 1.8 parts. The vinyl chloride-based graft copolymer latex (G-9) was used to evaluate the mechanical stability.

<Post-processing>
The obtained vinyl chloride graft copolymer latex (G-9) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride graft copolymer (P-9). , Various physical properties were evaluated.

(Comparative Example 1)
<Polymerization of rubber part>
230 parts of water, 5.5 parts of sodium dioctyl sulfosuccinate, and 0.1 parts of sodium carbonate were charged into a polymerization vessel equipped with a stirrer, the temperature was raised to 80 ° C. after nitrogen replacement, and 0.01 parts of potassium persulfate was added. A mixed solution of 90 parts of butyl acrylate, 10 parts of methyl methacrylate and 1.2 parts of allyl methacrylate was continuously added over 300 minutes, and after further polymerization for 60 minutes, the polymerization conversion rate was 99%, the solid content concentration was 30%, and the average. A rubber latex (ratio R-1) containing an acrylic rubber having a particle diameter of 39 nm was obtained.

<Polymerization of graft part>
Then, the rubber part latex (ratio R-1) 193 parts (solid content 58 parts), water 230 parts, ferrous sulfate (FeSO ₄ .7H ₂ O) 0.0012 parts, EDTA 2Na 0.0021 parts, formaldehyde 0.054 parts of sodium sulfoxylate were placed in a polymerization vessel equipped with a stirrer. After deoxidizing, 56 parts of vinyl chloride monomer was charged, the temperature was raised to 65 ° C., and an aqueous solution of hydrogen peroxide (0.06%) was continuously added for 135 minutes so that the hydrogen peroxide became 0.03 part. Was added. The reaction was stopped when the internal pressure dropped to 0.3 MPa. The polymerization conversion rate was 75%. Unreacted vinyl chloride was removed to obtain a vinyl chloride-based graft copolymer latex (ratio G-1) containing a vinyl chloride-based graft copolymer having an average particle size of 64 nm. When calculated based on the polymerization conversion rate, the vinyl chloride content in 100 parts of the vinyl chloride-based graft copolymer was 42 parts. That is, the vinyl chloride-based graft copolymer of Comparative Example 1 was composed of 58 parts of rubber part and 42 parts of graft part. In the vinyl chloride graft copolymer latex (ratio G-1), the glass transition temperature of the vinyl chloride graft copolymer was 22 ° C., and the glass transition temperatures of the rubber part and the graft part were not observed. In the obtained vinyl chloride-based graft copolymer latex (ratio G-1), the total amount of sodium dioctylsulfosuccinate added was 100 parts based on 100 parts of the vinyl chloride-based graft copolymer. The vinyl chloride graft copolymer latex (ratio G-1) was used to evaluate the mechanical stability.

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (ratio G-1) is coagulated with calcium chloride, subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (ratio P-1). Was obtained and various physical properties were evaluated.

(Comparative example 2)
(Polymerization of rubber part and graft part)
The rubber part and the graft part were polymerized in the same manner as in Comparative Example 1 to obtain a vinyl chloride-based graft copolymer latex (ratio G-1). To the obtained vinyl chloride-based graft copolymer latex (ratio G-1), 2.3 parts of sodium dioctylsulfosuccinate was further added, and the total addition of sodium dioctylsulfosuccinate to 100 parts of the vinyl chloride-based graft copolymer was added. A vinyl chloride-based graft copolymer latex (ratio M-2) was prepared so that the amount was 5.5 parts. The vinyl chloride graft copolymer latex (ratio M-2) was used to evaluate the mechanical stability.

(Post-processing)
The obtained vinyl chloride-based graft copolymer latex (ratio M-2) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (ratio P-2). Was obtained and various physical properties were evaluated.

(Comparative example 3)
<Polymerization of rubber part>
230 parts of water, 5.5 parts of sodium dioctyl sulfosuccinate, and 0.1 parts of sodium carbonate were charged into a polymerization vessel equipped with a stirrer, the temperature was raised to 80 ° C. after nitrogen replacement, and 0.01 parts of potassium persulfate was added. A mixed solution of 90 parts of butyl acrylate and 1.08 part of allyl methacrylate was continuously added over 270 minutes, and 30 minutes after the addition was completed, 10 parts of methyl methacrylate was continuously added over 30 minutes, and after 60 minutes of polymerization, polymerization conversion was performed. A rubber latex (ratio R-3) containing acrylic rubber having a rate of 99%, a solid content concentration of 30%, and an average particle diameter of 49 nm was obtained. In the obtained rubber part latex (ratio R-3), 100 parts of the rubber part is formed of an inner layer composed of 90 parts of butyl acrylate and an outer layer composed of 10 parts of methyl methacrylate.

<Polymerization of graft part>
Then, the rubber part latex (ratio R-3) 181 parts (solid content 54.4 parts), water 230 parts, ferrous sulfate (FeSO ₄ .7H ₂ O) 0.0012 parts, EDTA.2Na 0.0021 parts Then, 0.054 parts of sodium formaldehyde sulfoxylate was charged into a polymerization vessel equipped with a stirrer. After deoxidizing, 61 parts of vinyl chloride monomer was charged, the temperature was raised to 65 ° C., and an aqueous solution of hydrogen peroxide (0.06%) was continuously added for 135 minutes so that the hydrogen peroxide became 0.03 part. Was added. The reaction was stopped when the internal pressure dropped to 0.3 MPa. The polymerization conversion rate was 75%. Unreacted vinyl chloride was removed to obtain a vinyl chloride-based graft copolymer latex (ratio G-3) containing a vinyl chloride-based graft copolymer having an average particle size of 70 nm. When calculated based on the polymerization conversion rate, the vinyl chloride content was 45.6 parts in 100 parts of the vinyl chloride-based graft copolymer. That is, the vinyl chloride-based graft copolymer of Example 8 was composed of 54.4 parts of rubber part and 45.6 parts of graft part. In the vinyl chloride graft copolymer latex (ratio G-3), the glass transition temperature of the vinyl chloride graft copolymer was 22 ° C., and the glass transition temperatures of the rubber part and the graft part were not observed. In the obtained vinyl chloride-based graft copolymer latex (ratio G-3), the total amount of sodium dioctylsulfosuccinate added to 100 parts of the vinyl chloride-based graft copolymer was 3.0 parts. The mechanical stability was evaluated using the vinyl chloride-based graft copolymer latex (ratio G-3).

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (ratio G-3) is coagulated with calcium chloride, subjected to heat treatment, dehydration treatment and drying treatment, and powdered vinyl chloride-based graft copolymer (ratio P-3). Was obtained and various physical properties were evaluated.

(Comparative example 4)
<Polymerization of rubber part>
A rubber part latex containing an acrylic rubber having a polymerization conversion rate of 99%, a solid content concentration of 30% and an average particle diameter of 56 nm was prepared in the same manner as in Comparative Example 3 except that the emulsifier was changed to 4.5 parts of sodium dioctylsulfosuccinate. Ratio R-4) was obtained.

<Polymerization of graft part>
Then, the conversion of polymerization was performed in the same manner as in Comparative Example 3 except that 194 parts (solid content: 58.2 parts) of the rubber latex (ratio R-4) and 4.3 parts of sodium dioctylsulfosuccinate were used as emulsifiers in the graft part. Was obtained, and a vinyl chloride graft copolymer latex containing a vinyl chloride graft copolymer having an average particle diameter of 60% and a mean particle diameter of 60 nm (ratio G-4) was obtained. In the vinyl chloride graft copolymer latex (ratio G-4), the glass transition temperature of the vinyl chloride graft copolymer was 22 ° C., and the glass transition temperatures of the rubber part and the graft part were not observed. When calculated based on the polymerization conversion rate, the vinyl chloride content was 41.8 parts in 100 parts of the vinyl chloride-based graft copolymer. That is, the vinyl chloride graft copolymer of Comparative Example 1 was composed of 58.2 parts of rubber part and 41.8 parts of graft part. In the obtained vinyl chloride graft copolymer latex (ratio G-4), the total amount of sodium dioctylsulfosuccinate added was 6.9 parts based on 100 parts of the vinyl chloride graft copolymer. The vinyl chloride graft copolymer latex (ratio G-4) was used to evaluate the mechanical stability.

<Post-processing>
The obtained vinyl chloride-based graft copolymer latex (ratio G-4) is coagulated with calcium chloride and subjected to heat treatment, dehydration treatment and drying treatment to obtain a powdery vinyl chloride-based graft copolymer (ratio P-4). Was obtained and various physical properties were evaluated.

  Table 1 below shows the results of evaluation of transparency and flexibility performed using the powdery vinyl chloride-based graft copolymers obtained in Examples and Comparative Examples. In addition, Table 1 below shows the results of evaluation of mechanical stability using the vinyl chloride-based graft copolymer latexes obtained in Examples and Comparative Examples. Table 1 below also shows the conditions of emulsion polymerization and the like. In Table 1 below, the amount of the emulsifier is based on 100 parts by mass of the vinyl chloride-based graft copolymer.

  As can be seen from the data in Table 1, when a graft copolymer composed of a rubber portion and a graft portion polymerized by emulsion polymerization and having an average particle diameter of 100 nm or less is obtained, an oil-soluble peroxide type polymer is used for the emulsion polymerization of the rubber portion. In Examples 1 to 9 using the initiator, the mechanical stability of the graft copolymer latex was good, and the transparency of the molded product using the graft copolymer was also high. As can be seen from the comparison of Examples 1, 7 and 8, the transparency is further improved when the alkenyl succinate is used as the emulsifier. As can be seen from the comparison of Examples 1 to 6, when the rubber part has a plurality of layers, the inner layer is composed of a structural unit derived from alkyl acrylate, and the outer layer is composed of a structural unit derived from alkyl methacrylate, Stability is further improved. In Examples 1 to 8 in which the content of the rubber part in 100 parts by mass of the graft copolymer is 30 parts by mass or more, the tensile elastic modulus is 500 MPa or less, and it can be suitably used for soft applications. In Example 9 in which the content of the rubber part in 100 parts by mass of the graft copolymer is less than 30 parts by mass, the tensile elastic modulus is more than 500 MPa and can be suitably used for hard applications.

  On the other hand, in Comparative Examples 1 to 4 in which the water-soluble polymerization initiator was used for emulsion polymerization of the rubber portion, both mechanical stability and transparency of the graft copolymer could not be achieved. Specifically, when comparing Example 2 and Comparative Example 1 in which the total amount of the emulsifier added is equivalent, the transparency is equivalent, but the aggregation rate of Comparative Example 1 exceeds 30%, and mechanical stability is high. I didn't like it. In Comparative Example 2 in which the total amount of the emulsifiers added was increased to reduce the agglomeration rate to a level equivalent to that of Example 2, the haze was more than 50 and the transparency was poor. Further, in Comparative Example 3 in which the total amount of the emulsifier added was decreased to improve the transparency, the aggregation rate was more than 30%, and the mechanical stability was poor. Further, in Comparative Example 4 in which the total amount of the emulsifier added was increased to improve the mechanical stability, the haze was over 50, and the transparency was poor.

  FIG. 1 shows the results of dynamic viscoelasticity of the graft copolymers of Example 1 and Comparative Example 1 measured at a frequency of 1 HZ, a strain of 0.05%, and a heating rate of 4 ° C./min. As can be seen from FIG. 1, in the case of Example 1, two peaks of the glass transition temperature derived from the rubber part on the low temperature side and the glass transition temperature derived from the graft part on the high temperature side are observed, while comparison is made. In the case of Example 1, only one peak derived from the graft copolymer was observed. This means that the coverage of the rubber part by the graft part is high in the examples.

Claims (5)

100 parts by mass of a vinyl monomer for a rubber part containing 80% by mass or more and 100% by mass or less of an alkyl acrylate, 0% by mass or more and 20% by mass or less of an alkyl methacrylate, and 0% by mass or more and 4% by mass or less of another vinyl monomer, and polyfunctionality A first step of emulsion-polymerizing 0.1 part by mass or more and 5 parts by mass or less of a monomer to obtain an acrylic rubber;
Graft part containing 3 mass parts or more and 80 mass parts or less of the acrylic rubber obtained in the first step, and 80 mass% or more and 100 mass% or less of vinyl chloride monomer and 0 mass% or more and 20 mass% or less of other vinyl monomer. A method for producing a graft copolymer, comprising a second step of graft polymerizing 20 parts by weight or more and 97 parts by weight or less of a vinyl monomer for emulsion by emulsion polymerization to obtain 100 parts by weight of a graft copolymer,
The average particle size of the graft copolymer is 100 nm or less,
The method for producing a graft copolymer, wherein the polymerization initiator used in the first step is an oil-soluble peroxide-based initiator.   In the said graft copolymer, the glass transition temperature of a rubber part is 30 degrees C or less, and the glass transition temperature of a graft part exceeds 30 degreeC, The manufacturing method of the graft copolymer of Claim 1.   The graft rubber according to claim 1 or 2, wherein the acrylic rubber has a plurality of layers, the inner layer is composed of a structural unit derived from an alkyl acrylate, and the outer layer is composed of a structural unit derived from an alkyl methacrylate. Manufacturing method of coalescence.   The method for producing a graft copolymer according to claim 1, wherein the emulsifier used in at least one of the first step and the second step is an alkenyl succinate.   A method for producing a molded article, comprising obtaining a molded article using the graft copolymer obtained by the method for producing a graft copolymer according to claim 1.