JPH1087761A - Vinyl chloride-based graft copolymer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject copolymer excellent in impact resistance while maintaining tensile strength and modulus in flexure, by subjecting a mixed monomer such as acrylate to graft copolymerization and further subjecting vinyl chloride to graft copolymerization. SOLUTION: A mixed monomer in an amount of 30-95wt.% comprising 100 pts.wt. of (meth)acrylate having -140 to 30 deg.C glass transition temperature as homopolymer and 0.1-30pts.wt. of a polyfunctional monomer is subjected to graft copolymerization to 5-70wt.% of a copolymer comprising 100 pts.wt. of a radically polymerizable monomer (e.g. methyl methacrylate) having 30-180 deg.C glass transition temperature as homopolymer and 0.1-30 pts.wt. of a polyfunctional monomer [e.g. ethylene glycol (methacrylate) to give a copolymer. Vinyl chloride or a vinyl monomer consisting essentially of vinyl monomer in an amount of 99-70wt.% is subjected to graft copolymerization to 1-30wt.% of the copolymer to give the objective copolymer suitable as a molding material for piping material, conduct, sizing material, sash, etc., in a cold district.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vinyl chloride graft copolymer having excellent impact resistance and a method for producing the same.

[0002]

2. Description of the Related Art A vinyl chloride resin is a material excellent in mechanical strength, weather resistance and chemical resistance.
It is used in many applications such as hard PVC pipes, rain gutters and siding materials. However, for applications of hard vinyl chloride resin outdoors where long-term weather resistance and impact resistance are required, conventional impact modifiers based on unsaturated elastomers such as polybutadiene and styrene-butadiene rubber are not sufficient. Met. Therefore, a vinyl chloride resin obtained by graft copolymerizing vinyl chloride with an acrylic copolymer having a low glass transition temperature and excellent weather resistance has been proposed.
Japanese Patent No. 25555813 discloses a method in which vinyl chloride is subjected to suspension polymerization in the presence of an acrylic copolymer latex obtained by emulsion polymerization.

[0003] However, when an elastic component having a low glass transition temperature as described above is mixed with a hard vinyl chloride resin, the resulting composition generally has an increase in the amount of the elastic component mixed, as well as an increase in tensile strength and bending strength. There is a tendency for mechanical strength such as elastic modulus to decrease, and it has been industrially demanded to improve impact resistance while maintaining mechanical strength. As a method for improving this, for example, Japanese Patent Laid-Open No.
No. 06 discloses that the homopolymer has a secondary transition temperature of −10 ° C.
A method in which vinyl chloride is graft-copolymerized to the following three acrylic copolymers of an alkyl (meth) acrylate, a styrene monomer having a glass transition temperature higher than room temperature, and a polyfunctional monomer has been proposed. However, it was not enough to improve impact resistance while maintaining mechanical strength such as flexural modulus.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a molded article having excellent impact resistance while maintaining the mechanical strength of a conventional vinyl chloride resin. An object of the present invention is to provide a vinyl-based graft copolymer and a method for producing the same.

[0005]

According to a first aspect of the present invention, there is provided a process for producing a vinyl chloride-based graft copolymer, wherein the homopolymer has a glass transition temperature of 30 ° C. or higher. Radical polymerizable monomer 10 of 180 ° C. or less
100 parts by weight of a (meth) acrylate having a glass transition temperature of -140 or more and less than 30 ° C in 5 to 70% by weight of a copolymer consisting of 0 parts by weight and 0.1 to 30 parts by weight of a polyfunctional monomer. 1 to 30% by weight of a copolymer obtained by graft copolymerization of 30 to 95% by weight of a mixed monomer composed of 0.1 to 30 parts by weight of polyfunctional monomer and vinyl chloride or vinyl chloride as a main component Vinyl monomer 9
It is characterized in that 9 to 70% by weight is graft copolymerized.

The invention described in claim 2 of the present application (hereinafter referred to as “second
The invention is referred to as the invention).
It is obtained by the manufacturing method of the invention.

The method for producing a vinyl chloride graft copolymer according to the first invention is a method of graft copolymerizing vinyl chloride or a vinyl monomer containing vinyl chloride as a main component to acrylic copolymer particles having a specific core / shell structure. It is characterized by being polymerized.

Acrylic copolymer particles having a specific core / shell structure have a homopolymer having a glass transition temperature of 3
Radical polymerizable monomer (A) having a temperature of 0 ° C to 180 ° C
And the polyfunctional monomer (B) are copolymerized to form a core. On the outer surface of the core, a (meth) acrylate having a glass transition temperature of a homopolymer of −140 or more and less than 30 ° C. A mixed monomer composed of C) and the polyfunctional monomer (B) is graft-copolymerized to form a shell structure. At the interface between the core and the shell, a graft copolymer of the monomers constituting the respective interfaces is formed and firmly compatible and bonded.

As the radical polymerizable monomer (A) which forms a tough polymer chain in the copolymer constituting the core, the homopolymer has a glass transition temperature of 30 ° C. or higher and 18 ° C. or lower.
It is necessary that the temperature be 0 ° C. or lower, and the vinyl chloride graft copolymer obtained by using the same has sufficient toughness when used at normal temperature. When the temperature is lower than 30 ° C., the graft copolymer is too soft and the mechanical strength is low. When the temperature exceeds 180 ° C., the graft copolymer is too hard and the impact resistance is low.

The radical polymerizable monomer (A) having a homopolymer having a glass transition temperature of 30 ° C. to 180 ° C. includes, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, isobutyl methacrylate Acrylate, s
alkyl (meth) acrylates such as ec-butyl methacrylate, t-butyl (meth) acrylate, cumyl methacrylate, cyclohexyl methacrylate, palmityl acrylate, stearyl acrylate;
Polar group-containing vinyl monomers such as hydroxyethyl methacrylate and 2-acryloyloxyethyl phthalic acid;
Styrene, α-methylstyrene, p-methylstyrene,
aromatic vinyl monomers such as p-chlorostyrene; unsaturated nitriles such as acrylonitrile and methacrylonitrile;
Examples thereof include vinyl esters such as vinyl acetate and vinyl propionate, and these may be used alone or in combination.

The radical polymerizable monomer which forms a flexible polymer chain having a flexible skeleton in the copolymer constituting the shell is (meth) acrylate (C) having a low glass transition temperature of a homopolymer. It is necessary that the homopolymer has a glass transition temperature of −140 ° C. or more and less than 30 ° C., and the vinyl chloride graft copolymer obtained by using the same has sufficient impact resistance at room temperature. It will be. When the temperature is lower than −140 ° C., the vinyl chloride graft copolymer obtained by using the same has satisfactory low-temperature impact resistance at room temperature, but is too soft and has insufficient mechanical strength. If the temperature is higher than ℃, the impact resistance becomes low.

As the (meth) acrylate (C) having a homopolymer having a glass transition temperature of -140 or more and less than 30 ° C.,
For example, methyl acrylate, ethyl acrylate, n
-Propyl acrylate, isopropyl acrylate,
n-butyl (meth) acrylate, isobutyl acrylate, sec-butyl acrylate, cumyl acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-methylheptyl (meth) ) Acrylate, 2-
Ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, 2-methyloctyl (meth) acrylate, 2-ethylheptyl (meth) acrylate, n
-Decyl (meth) acrylate, cyclohexyl acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate, palmityl methacrylate,
Examples thereof include alkyl (meth) acrylates such as stearyl methacrylate, 2-hydroxyethyl acrylate, and 2-hydroxypropyl (meth) acrylate, and these may be used alone or in combination.

The polyfunctional monomer (B) is used for polymerizing acrylic copolymer particles having a core / shell structure.
There are three main roles. That is, first, the copolymer of the core and the shell is cross-linked to improve the impact resistance of the vinyl chloride-based graft copolymer. Second, at the time of polymerization or after the polymerization, a dispersion in water is used. The third is to prevent the latex from coalescing. Thirdly, when the core and shell are polymerized step by step, the added monomer is prevented from diffusing into the layer where polymerization has been completed and mixing. To synthesize particles having a typical core / shell structure.

Examples of the polyfunctional monomer (B) include di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth) acrylate.
Acrylates, 1,6-hexanediol di (meth) acrylate, trimethylolpropane di (meth) acrylate, and the like are listed. As tri (meth) acrylate, for example, trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylol And propane tri (meth) acrylate and pentaerythritol tri (meth) acrylate.

Other polyfunctional monomers include, for example, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, diallyl phthalate, diallyl maleate, diallyl fumarate, diallyl succinate, triallyl isocyanate Examples thereof include diallyl or triallyl compounds such as nurate, and divinyl compounds such as divinylbenzene and butadiene. These may be used alone or in combination.

In forming the core copolymer, the addition amount of the polyfunctional monomer (B) must be 0.1 to 30 parts by weight based on 100 parts by weight of the radical polymerizable monomer (A). And more preferably 0.3 to 5 parts by weight. When the amount is less than 0.1 part by weight, phase mixing of the copolymer of the core and the shell occurs, and the impact resistance of the vinyl chloride-based graft copolymer decreases. Crosslinking occurs and the resulting vinyl chloride-based graft copolymer cannot have impact resistance.

In forming the copolymer constituting the shell, the amount of the polyfunctional monomer (B) is 0.1 to 30 parts by weight based on 100 parts by weight of the (meth) acrylate (C).
Parts by weight are required, and more preferably 0.3 to 8 parts by weight. When the amount is less than 0.1 part by weight, phase mixing of the copolymer of the core and the shell occurs, and the impact resistance of the vinyl chloride-based graft copolymer decreases. Crosslinking occurs and the resulting vinyl chloride-based graft copolymer cannot have impact resistance.

The weight ratio of the core of the acrylic copolymer particles having the core / shell structure must be 5 to 70% by weight, and if it is less than 5% by weight, the sufficient amount of the vinyl chloride graft copolymer will be sufficient. If the mechanical strength is not obtained, and if it exceeds 70% by weight, impact resistance cannot be obtained. Similarly, the weight ratio of the shell of the acrylic copolymer particles having the core / shell structure must be 95 to 30% by weight, and if it is less than 30% by weight, the impact resistance of the vinyl chloride-based graft copolymer is reduced. When the content exceeds 95% by weight, sufficient mechanical strength cannot be obtained.

The method for obtaining the acrylic copolymer particles having a core / shell structure is not particularly limited, and examples thereof include an emulsion polymerization method and a suspension polymerization method. Among them, the emulsion polymerization method is preferred because the impact resistance is easily developed and the control of the copolymer particles is easy.

The emulsifying and dispersing agent used for emulsion polymerization is added for the purpose of emulsifying a monomer in water and polymerizing it into stable particles. For example, anionic surfactants, nonionic surfactants, Saponified polyvinyl acetate, cellulose-based dispersant, gelatin and the like are mentioned. In particular, anionic surfactant polyoxyethylene nonylphenyl ether sulfate (trade name “HITENOL N-08” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is used. It is preferably used.

As the polymerization initiator for emulsion polymerization, for example,
Water-soluble polymerization initiators such as potassium persulfate, ammonium persulfate and aqueous hydrogen peroxide; organic peroxides such as benzoyl peroxide and lauroyl peroxide; and azo initiators such as azobisisobutyronitrile. or,
In the emulsion polymerization method, a pH adjuster, an antioxidant and the like may be added as necessary.

Emulsion polymerization methods are roughly classified into three methods: a batch polymerization method, a monomer dropping method, and an emulsion dropping method, depending on the method of adding a monomer. What is the batch polymerization method?
For example, pure water, an emulsifying dispersant, a polymerization initiator, and monomers are collectively added into a jacketed polymerization reaction vessel, nitrogen gas is introduced, oxygen is removed, and then pressurized with nitrogen gas. This is a method in which the mixture is sufficiently stirred and emulsified, and thereafter, a heating medium is introduced into the jacket to carry out heat polymerization.

In the monomer dropping method, for example, pure water, an emulsifying dispersant, and a polymerization initiator are placed in a jacketed polymerization reaction vessel, nitrogen gas is introduced to remove oxygen, and then added with nitrogen gas. Press, stir well and emulsify, then
In this method, a heating medium is introduced into a jacket, the reaction vessel is heated and placed, and a predetermined amount of the monomer is added dropwise to gradually polymerize.

The emulsion dropping method is a method in which a monomer, pure water and an emulsifying dispersant are stirred and sufficiently emulsified.
An emulsified monomer is prepared and placed in advance, then pure water and a polymerization initiator are put into a jacketed polymerization reaction vessel and stirred, nitrogen gas is introduced to remove oxygen, and then pressurized with nitrogen gas. Then, after that, a heating medium is introduced into the jacket, the reaction vessel is heated and placed, and a predetermined amount of the emulsified monomer is dropped to carry out polymerization. Further, in the emulsion dropping method, a method in which a part of the above-mentioned emulsifying monomer is added all at once (hereinafter, referred to as a seed monomer) at the beginning of polymerization, and thereafter, the remaining emulsifying monomer is dropped, is used. By changing the particle size, the particle size of the latex can be easily controlled.

To form an acrylic copolymer latex having a core / shell structure, any of the above three monomer addition methods may be employed. Specifically, in order to prepare a core copolymer latex, emulsion polymerization is carried out by adding a mixed monomer or an emulsified monomer all at once or by dropping. Subsequently, in the presence of the obtained copolymer latex of the core, a mixed monomer or emulsified monomer to be newly formed as a shell is added at once, or added dropwise, emulsion polymerization is performed, and the outside of the core copolymer particles is removed. Then, a latex in which a copolymer of an elastic component, which is a copolymer of a shell, is formed is obtained.

The resin solid content of the acrylic copolymer latex having the core / shell structure is not particularly limited, but is preferably 10 to 60% by weight in consideration of the productivity of the latex and the stability of the polymerization reaction. preferable. In addition, the average resin particle diameter of the acrylic copolymer latex is 0.01 to 1
μm is preferred. If it is less than 0.01 μm, the impact resistance of the vinyl chloride graft copolymer tends to decrease, and if it exceeds 1 μm, both the impact resistance and the tensile strength decrease.

After the latex polymerization reaction, a predetermined amount of a protective colloid may be appropriately added to the acrylic copolymer latex having the core / shell structure in order to improve the mechanical stability of the latex. .

The ratio of the acrylic copolymer having a core / shell structure (solid content of latex) to the vinyl chloride graft copolymer must be 1 to 30% by weight, more preferably 4 to 10% by weight. %. If the amount is less than 1% by weight, sufficient impact resistance cannot be obtained. If the amount exceeds 30% by weight, mechanical strength such as bending strength and tensile strength decreases.

In a method in which vinyl chloride alone or a monomer containing vinyl chloride as a main component is graft-copolymerized to an acrylic copolymer latex having a core / shell structure,
The monomer containing vinyl chloride as a main component means a mixture of 50% by weight or more of vinyl chloride and a copolymerizable vinyl monomer, and the copolymerizable vinyl monomer is a commonly known vinyl monomer. For example, vinyl acetate, alkyl (meth) acrylate, alkyl vinyl ether, ethylene, vinyl fluoride, maleimide and the like can be mentioned, and these may be used alone or in combination.

A method of graft copolymerizing vinyl chloride alone or a monomer containing vinyl chloride as a main component to an acrylic copolymer latex having a core / shell structure is as follows.
In particular, but not limited to, bulk polymerization method, solution polymerization method, emulsion polymerization method, suspension polymerization method, etc., are considered from the viewpoint of economy and various physical properties such as thermal stability of the obtained vinyl chloride resin. Then, the suspension polymerization method is suitable. In the suspension polymerization method, a dispersant and an oil-soluble polymerization initiator are used, and an acrylic copolymer latex having a core / shell structure is used in order to reduce adhesion of scale in the polymerization tank during polymerization. , A coagulant may be added.

The dispersing agent is added for the purpose of improving the dispersion stability of the acrylic copolymer having a core / shell structure and effectively performing the graft polymerization of vinyl chloride alone or a monomer containing vinyl chloride as a main component. For example, poly (meth) acrylic acid, (meth) acrylate-alkyl acrylate copolymer, methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, polyethylene glycol, polyvinyl alcohol, polyvinyl acetate and partially saponified products thereof, gelatin, polyvinylpyrrolidone , Starch, maleic anhydride-styrene copolymer, and the like, which may be used alone or in combination.

The oil-soluble polymerization initiator is selected from the reason that the graft efficiency of vinyl chloride to the acrylic copolymer is improved as compared with the water-soluble polymerization initiator. For example, lauroyl peroxide, t-butyl peroxypi Organic peroxides such as valate, diisopropyl peroxydicarbonate, dioctyl peroxydicarbonate, t-butyl peroxy neodecanoate, α-cumyl peroxy neodecanoate, 2,2-azobisisobutyronitrile And azo compounds such as 2,2-azobis-2,4-dimethylvaleronitrile. or,
In the suspension polymerization method, a pH adjuster, an antioxidant, and the like may be added as necessary.

As a specific example of the above suspension polymerization method, pure water, an acrylic copolymer latex having a three-layer structure, a dispersant, and an oil-soluble polymerization initiator are placed in a pressure-resistant reaction vessel equipped with a stirrer and a jacket. And a water-soluble thickener (protective colloid) and, if necessary, a polymerization regulator. Thereafter, the air in the reaction vessel is removed by a vacuum pump, vinyl chloride alone or a monomer containing vinyl chloride as a main component is charged with stirring, and the reaction vessel is heated through a jacket to start polymerization. Since the above-mentioned polymerization reaction generates heat, the reaction temperature can be controlled by adjusting the temperature of the jacket. After completion of the reaction, unreacted monomers such as vinyl chloride are removed to form a slurry, which is then dehydrated and dried to produce an impact-resistant vinyl chloride-based graft copolymer.

The degree of polymerization of the non-grafted vinyl chloride resin among the vinyl chloride resins is 300 to 2000.
And more preferably 400 to 1600. If it is less than 300, the physical properties of the obtained vinyl chloride-based graft copolymer cannot be sufficiently obtained, and if it exceeds 2,000, the fluidity during molding is poor and various moldings are difficult.

The vinyl chloride-based graft copolymer of the second invention is obtained by the production method of the first invention, and may be used, if necessary, at the time of molding, as a heat stabilizer, a stabilizing aid, a lubricant, a processing aid, an oxidizing agent. Inhibitors, light stabilizers, fillers, pigments and the like are added.

Examples of the heat stabilizer include dimethyltin mercapto, dibutyltin mercapto, dioctyltin mercapto, dibutyltin maleate, dibutyltin maleate polymer, dioctyltin malate, dioctyltin maleate polymer, dibutyltin laurate, and dibutyltin laurate. Organotin stabilizers such as rate polymers, lead-based stabilizers such as lead stearate, dibasic lead phosphite, and tribasic lead sulfate;
Examples include a zinc-based stabilizer, a barium-zinc-based stabilizer, and a barium-cadmium-based stabilizer, and these may be used alone or in combination.

Examples of the stabilizing aid include epoxidized soybean oil, epoxidized linseed oil, epoxidized tetrahydrophthalate, epoxidized polybutadiene, and phosphoric acid ester. These may be used alone or in combination. May be done.

Examples of the lubricant include montanic acid wax, paraffin wax, polyethylene wax, stearic acid, stearyl alcohol, butyl stearate and the like, and these may be used alone or in combination.

Examples of the processing aid include an acrylic processing aid which is an alkyl acrylate-alkyl methacrylate copolymer having a weight average molecular weight of 100,000 to 2,000,000, such as an n-butyl acrylate-methyl methacrylate copolymer. -Ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer and the like, and these may be used alone or in combination.

Examples of the antioxidant include a phenolic antioxidant. Examples of the light stabilizer include a salicylic acid ester-based, benzophenone-based, benzotriazole-based, cyanoacrylate-based ultraviolet absorber, and a hindered amine-based light stabilizer, and these may be used alone. , May be used in combination.

Examples of the filler include calcium carbonate, talc and the like. Examples of the pigment include organic pigments such as azo, phthalocyanine, sulene, and dye lakes, oxides, molybdenum chromate, and sulfides.
Inorganic pigments such as selenide and ferrocyanide are exemplified.

Further, the vinyl chloride graft copolymer includes:
For the purpose of improving workability during molding, a plasticizer may be added. For example, dibutyl phthalate, di-2-
Ethylhexyl phthalate, di-2-ethylhexyl adipate and the like can be mentioned.

As a method for mixing the above-mentioned various additives with the vinyl chloride-based graft copolymer, either hot blending or cold blending may be used. Examples of the molding method include an extrusion molding method, an injection molding method, a calendar molding method, and a press molding method. Molding method and the like.

[0044]

The production method of the present invention is, as described above, an acrylic copolymer having a core / shell structure of a high glass transition temperature resin / low glass transition temperature resin (ie, a crosslinked hard resin / crosslinked rubber-like elastic material). Since vinyl chloride or a vinyl monomer containing vinyl chloride as a main component is graft-copolymerized into the latex, the obtained vinyl chloride-based graft copolymer of the present invention has tensile strength and flexural modulus maintained, It becomes a resin with excellent impact resistance.

The reason why the above-mentioned performance is obtained is assumed as follows. That is, latex particles having a core / shell structure composed of a crosslinked hard resin / crosslinked rubber-like elastic material are fine particles having a structure in which a rubber elastic component is firmly bonded to a hard resin having the same mechanical strength as a vinyl chloride resin. Since a vinyl chloride monomer is further graft-copolymerized on the fine particles, the vinyl chloride resin of the matrix resin is
The vinyl chloride-based graft copolymer of the present invention has a good dispersibility and compatibility property, and is in a form of a uniform reactor blend in the process. Further, since the core / shell structure in which the rubber elastic component is bonded to the hard resin is crosslinked as it is in the form of latex particles, even if subjected to thermoforming, the core / shell structure is not sufficiently melted and deformed. Since the particles are uniformly dispersed in the united structure, the impact resistance can be improved while maintaining the mechanical strength.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to explain the present invention in more detail, examples and comparative examples will be given.

Examples 1 to 9, Comparative Examples 2, 4 to 9 (1) Preparation of Acrylic Copolymer Latex with Core / Shell Structure (a) Preparation of Mixed Monomer with Core / Shell Structure (Emulsion Mixed Monomer for Core) According to the composition shown in Tables 1 and 2, a predetermined amount of pure water, an emulsifying dispersant (polyoxyethylene nonylphenyl ether ammonium sulfate), methyl methacrylate (glass transition temperature: 1)
05 ° C., hereinafter referred to as MMA) or styrene (glass transition temperature: 100 ° C.), trimethylolpropane triacrylate (hereinafter, referred to as TMPTA), and stirring,
The emulsified mixed monomer was prepared.

(Emulsion mixed monomer for shell) Tables 1 and 2
A predetermined amount of pure water, an emulsifying dispersant (polyoxyethylene nonylphenyl ether ammonium sulfate), n-butyl acrylate (glass transition temperature: -54 ° C, hereinafter, referred to as n-BA) or 2-
Ethylhexyl acrylate (glass transition temperature: -70
C., hereinafter referred to as 2-EHA), and TMPTA were mixed and stirred to prepare an emulsified mixed monomer.

(B) Emulsion polymerization of latex Next, pure water was placed in a reaction vessel equipped with a stirrer and a reflux condenser, and oxygen in the vessel was replaced with nitrogen. Then, the reaction vessel was heated to 70 ° C. while stirring. Warmed. After the completion of the temperature increase, half of the ammonium persulfate (hereinafter, referred to as APS) and half of the emulsified mixed monomer for the copolymer of the core are collectively charged as a seed monomer into the reaction vessel to start emulsion polymerization,
Subsequently, half of the remaining emulsified mixed monomer for core was dropped. When the dropping of the emulsified mixed monomer for core is completed,
Immediately, the dropping of the emulsified mixed monomer for shell was started.
The dripping of all the emulsified mixed monomers was completed in 3 hours, and thereafter, after an aging period of 1 hour, the emulsion polymerization was terminated,
An acrylic copolymer latex (hereinafter referred to as latex) having a core / shell structure having a solid content of 30% by weight was obtained.

[0050]

[Table 1]

[0051]

[Table 2]

(2) Preparation of vinyl chloride graft copolymer In a reaction vessel equipped with a stirrer and a jacket, as shown in Tables 3 and 4, 3% by weight of pure water, the above latex, and partially saponified polyvinyl acetate were added. The aqueous solution, t-butyl peroxy neodecanoate, and α-cumyl peroxy neodecanoate were added all at once. Thereafter, the air in the polymerization vessel was exhausted by a vacuum pump, vinyl chloride was charged with stirring, and the polymerization was started by controlling the temperature of the reaction vessel to 50 ° C. When the pressure in the reaction vessel dropped to 5 kg / cm ² , the completion of the reaction was confirmed, and the reaction was stopped.

Thereafter, the unreacted vinyl chloride monomer is removed, and further dehydration drying is performed to obtain a vinyl chloride-based graft copolymer having a polymerization degree of the vinyl chloride resin of about 1400 in the vinyl chloride-based graft copolymer. Obtained. The results are shown in Tables 3 and 4.

[0054]

[Table 3]

[0055]

[Table 4]

Comparative Example 1 A vinyl chloride graft copolymer was synthesized in the same manner as in Examples 1 to 9 except that an acrylic copolymer latex having no core was used in accordance with the composition shown in Table 2. The results are shown in Table 4.

Comparative Example 3 A vinyl chloride-based graft copolymer was synthesized in the same manner as in Examples 1 to 9, except that an acrylic copolymer latex having no shell was used in accordance with the composition shown in Table 2. The results are shown in Table 4.

Evaluation method (impact resistance) The Charpy impact test was performed according to JIS K711.
The measurement was performed at a measurement temperature of 23 ° C. in accordance with No. 1. As a sample, a resin composition obtained by mixing 0.5 parts by weight of an organotin-based stabilizer and 1.0 parts by weight of a montanic acid-based lubricant with respect to 100 parts by weight of a vinyl chloride-based graft copolymer was rolled at 200 ° C. for 3 minutes. After kneading, a thickness of 3 obtained by press molding at 200 ° C. for 3 minutes.
mm.

(Tensile strength) JIS K7 at a temperature of 23 ° C.
113. The sample was produced from the press plate used for the above Charpy impact test.

[0060]

Since the production method of the present invention is constituted as described above, the vinyl chloride graft copolymer of the present invention having excellent impact resistance while maintaining tensile strength and flexural modulus. Is obtained. Therefore, the molded article obtained by using this can be used for a wide range of applications such as piping materials, gutters, siding materials, and sashes in cold regions.

Claims (2)

[Claims] 1. A copolymer comprising 100 parts by weight of a radical polymerizable monomer having a glass transition temperature of a homopolymer of 30 ° C. or more and 180 ° C. or less and 0.1 to 30 parts by weight of a polyfunctional monomer. A (meth) acrylate 10 having a homopolymer having a glass transition temperature of −140 ° C. or more and less than 30 ° C.
Vinyl chloride or vinyl chloride is mainly added to 1 to 30% by weight of a copolymer obtained by graft copolymerizing 30 to 95% by weight of a mixed monomer comprising 0 part by weight and 0.1 to 30 parts by weight of a polyfunctional monomer. Vinyl monomer 99 to 7 as a component
A method for producing a vinyl chloride-based graft copolymer, comprising graft-copolymerizing 0% by weight. 2. A vinyl chloride graft copolymer obtained by the production method according to claim 1.