JPH09316139A - Vinyl chloride resin and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vinyl chloride resin excellent in impact resistance, weathering resistance and tensile strength by grafting a vinyl monomer onto an acrylic copolymer onto which a polyfunctional monomer has been grafted. SOLUTION: 0.5 to 30 pts.wt. polyfunctional monomer is grafted onto 100 pts.wt. acrylic copolymer to obtain an acrylic copolymer latex having a mean resin particle diameter of 0.01-1μm. 0.01 to 10 pts.wt. protective colloid is added to 100 pts.wt. (in terms of solid matter) above latex. The resulting latex and vinyl chloride or a vinyl monomer mixture based thereon in such an amount that the latex amounts to 1-30wt.% are subjected to a graft copolymerization reaction to obtain a vinyl chloride resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin 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, in outdoor applications, long-term weather resistance, in particular, the impact resistance improver based on a conventional unsaturated elastic body such as polybutadiene, the performance was insufficient for the object requiring impact resistance, As a countermeasure against this, a vinyl chloride resin in which vinyl chloride is graft-copolymerized with an acrylic copolymer has been proposed. A method for producing these vinyl chloride resins is described in, for example, JP-A-60-255.
Japanese Patent No. 813 discloses a method of suspension-polymerizing vinyl chloride in the presence of an acrylic copolymer latex obtained by emulsion polymerization.

However, in the above-mentioned acrylic copolymer latex, an emulsifying dispersant layer is formed on the surface of the latex particles to form colloidal particles which are stable in water. Phenomenon with poor stability, where the emulsion / dispersant layer of latex particles is destroyed when they are subjected to pressure or shear stress in storage tanks, polymerization tanks, pipes, transfer pumps, etc., and latex particles aggregate and solidify. cause. Therefore, in the case of graft copolymerizing vinyl chloride onto an acrylic copolymer latex, which has poor mechanical stability, a hard coating (hereinafter referred to as scale) on the inner wall of the polymerization container, the stirring blade main shaft, the baffle plate, etc. Can easily adhere to the polymer layer, reduce the cooling capacity of the polymerized layer, block pipes and transfer pumps with scale deposits, and cause latex agglomerates such as scale to mix with vinyl chloride resin, resulting in poor quality. There is a defect.

As a method for producing an acrylic copolymer latex having improved mechanical stability, for example, Japanese Patent Publication No. 52-45754 discloses a method of using acrylic acid as a component of an acrylic copolymer. In addition, Japanese Patent Laid-Open No. Hei 7
JP-A-133473 proposes a method of emulsifying a rosin resin used as a tackifier in an acrylic adhesive in the presence of an emulsifier and a protective colloid. Further, Japanese Patent Publication No. 5-43731 discloses that when a vinyl chloride is graft-copolymerized with an acrylic copolymer latex, an acrylic copolymer is used as a method for producing a vinyl chloride resin having a small scale by a suspension polymerization method. A method is disclosed in which a polymer obtained by graft-polymerizing a monomer having a glass transition point of a homopolymer of 80 ° C. or higher to a united latex is disclosed. However, in these methods, the mechanical stability of the acrylic copolymer latex is still unsatisfactory in the graft copolymerization of vinyl chloride onto the acrylic copolymer.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and obtains an acrylic copolymer latex having excellent mechanical stability to obtain polymerization efficiency, impact resistance, weather resistance, An object of the present invention is to provide a vinyl chloride resin excellent in tensile strength and a method for producing the same.

[0006]

The method for producing a vinyl chloride resin of the invention according to claim 1 of the present application (hereinafter referred to as the first invention) is an acrylic copolymer obtained by graft-copolymerizing a polyfunctional monomer. The latex is characterized by graft-copolymerizing vinyl chloride alone or a vinyl monomer containing vinyl chloride as a main component.

The invention described in claim 2 of the present application (hereinafter referred to as “second
The method for producing a vinyl chloride resin according to the invention) is the method for producing a vinyl chloride resin according to the first invention, wherein the acrylic copolymer latex is polyfunctional with respect to 100 parts by weight of the acrylic copolymer. It is characterized in that the monomer is graft copolymerized in an amount of 0.5 to 30 parts by weight.

[0008] The invention described in claim 3 of the present application (hereinafter referred to as "third")
The method for producing a vinyl chloride resin according to the invention) is based on 100 parts by weight of the solid content of the acrylic copolymer latex.
0.01 to 10 parts by weight of a protective colloid is added, and vinyl chloride alone or a vinyl monomer containing vinyl chloride as a main component is graft-copolymerized with the acrylic copolymer latex.

The invention described in claim 4 of the present application (hereinafter referred to as the fourth invention)
The vinyl chloride resin according to the invention) is obtained by the production method according to claim 1 selected from claim 1 to claim 3.

The acrylic copolymer latex is composed of an alkyl (meth) acrylate (A), a radical-polymerizable monomer (B) or a polyfunctional monomer (C) capable of copolymerizing with an alkyl (meth) acrylate. Specifically, a copolymer latex comprising at least one kind of monomer selected from the group (A), at least one kind of monomer selected from the group (A) and (B Copolymer latex with at least one monomer selected from the group (A) and (C) at least one monomer selected from each group (partial crosslinking)
Examples of the polymer latex include copolymer latexes (partially crosslinked) with at least one monomer selected from the groups of (A), (B) and (C). Hereinafter, the acrylic copolymer latex will be referred to as a simple acrylic copolymer latex.

Therefore, in the method for producing a vinyl chloride resin of the first and second inventions, a polyfunctional monomer (C) is newly added to the above-mentioned simple acrylic copolymer latex to prepare a graft copolymer. Acrylic copolymer latex (hereinafter referred to as graft acrylic copolymer latex) obtained by polymerization and self-crosslinking reaction is graft-copolymerized with vinyl chloride alone or a vinyl monomer containing vinyl chloride as a main component. Characteristically, the method for producing a vinyl chloride resin according to the second aspect of the present invention comprises a graft acrylic copolymer latex in which the proportion of the polyfunctional monomer (C) is limited, and vinyl chloride alone or vinyl containing vinyl chloride as a main component. It is characterized in that a monomer is graft-copolymerized. The type of polyfunctional monomer used when synthesizing the acrylic copolymer latex is a simple acrylic copolymer latex,
The graft acrylic copolymer latex is optional and is not particularly limited.

Examples of the alkyl (meth) acrylate (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) Acrylate, 2-methylheptyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, 2-methyloctyl (meth) acrylate, n-nonyl (meth) acrylate, 2-ethylheptyl (meth) acrylate, n-decyl (meth) acrylate, 2-methylnonyl (meth) acrylate, 2-ethyloctyl (meta)
Alkyl (meth) acrylates such as acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, polar group-containing (meth) acrylates such as 2-hydroxypropyl (meth) acrylate And the like, and at least one of them can be used.

As the radically polymerizable monomer (B) capable of copolymerizing with an alkyl (meth) acrylate, the glass transition temperature of the acrylic copolymer latex is arbitrarily adjusted, and the impact resistance of the vinyl chloride resin obtained is obtained. It is used for the purpose of improving the properties of, for example, polar group-containing vinyl monomers such as 2-acryloyloxyethylphthalic acid, aromatic vinyl monomers such as styrene, α-styrene, p-chlorostyrene, vinyltoluene, acrylonitrile and methacrylonitrile. Unsaturated nitrile, vinyl acetate such as vinyl acetate, vinyl propionate, etc., and the like, and at least one of them can be used.

The polyfunctional monomer (C) acts as a partial cross-linking agent for the simple acrylic copolymer latex or the graft acrylic copolymer latex, contributes to the rubber elasticity of the latex particles, and disperses the latex particles in water. Agglomeration in liquid is less likely to occur. In particular, when a graft copolymer of latex is obtained by graft-copolymerizing a polyfunctional monomer (C) with a simple acrylic copolymer latex, the latex particles are crosslinked to obtain tensile strength, rigidity, Since it increases the elasticity and reduces the tackiness of the surface, it greatly contributes to the mechanical stability of the latex against stress. As a result, it was found that the mechanical stabilization of the latex by partial crosslinking of the latex described above plays a role of improving impact resistance and tensile strength of the vinyl chloride resin obtained by graft copolymerization of vinyl chloride. .

Examples of the polyfunctional monomer (C) include di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 1, Examples thereof include 6-hexanediol di (meth) acrylate and trimethylolpropane di (meth) acrylate. Examples of the tri (meth) acrylate include trimethylolpropane tri (meth) acrylate and ethylene oxide-modified trimethylolpropane 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 malate, diallyl fumarate, diallyl succinate, triallyl isocyanate. Examples thereof include diallyl or triallyl compounds such as nurate, divinyl compounds such as divinylbenzene and butadiene, and at least one of them is used.

The simple acrylic copolymer latex is further graft-copolymerized with a polyfunctional monomer (C),
The method of making a graft acrylic copolymer latex is
Although not particularly limited, for example, a method of emulsion-polymerizing the polyfunctional monomer (C) in the presence of a simple acrylic copolymer latex is a method in which the particle size of the latex can be easily controlled and the impact resistance is exhibited. It is preferable in terms of sex.

The amount of the polyfunctional monomer (C) added is preferably 0.5 to 30 parts by weight, more preferably 3 to 15 parts by weight, based on 100 parts by weight of the solid content of the simple acrylic copolymer latex. is there. If less than 0.5 parts by weight,
No sufficient improvement in the mechanical stability of the obtained graft acrylic copolymer latex was observed, and when it exceeds 30 parts by weight, excessive crosslinking occurs and the flexibility of the latex is reduced, resulting in the vinyl chloride obtained. The impact resistance of the resin cannot be obtained.

The emulsion dispersant used in the emulsion polymerization is added for the purpose of improving the stability of the monomer in the emulsion and performing the polymerization efficiently. Specific examples thereof include anionic surfactants, nonionic surfactants, partially saponified polyvinyl acetate, cellulose dispersants, gelatin, and the like. In particular, anionic surfactant polyoxyethylene nonylphenyl ether sulphate is used. (Daiichi Kogyo Seiyaku Co., Ltd., trade name "Hitenol N-08") is preferably used.

Examples of the polymerization initiator for emulsion polymerization include, 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 above emulsion polymerization method, a pH adjuster, an antioxidant and the like may be added as necessary.

The emulsion polymerization methods are roughly classified into three methods, that is, a batch polymerization method, a monomer dropping method, and an emulsion dropping method because of the difference in the method of adding the monomers. The batch polymerization method is, for example, collectively adding pure water, an emulsifying dispersant, a polymerization initiator, and monomers into a jacketed polymerization reaction vessel, introducing nitrogen gas, removing oxygen, and then This is a method in which the mixture is pressurized with nitrogen gas, sufficiently stirred and emulsified, and thereafter, a heating medium is introduced into a jacket to carry out heat polymerization.

The monomer dropping method is, for example, that pure water, an emulsifying dispersant and a polymerization initiator are put in a jacketed polymerization reaction vessel, nitrogen gas is introduced to remove oxygen, and then nitrogen gas is added. Press, stir well to 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.

In order to produce a simple acrylic copolymer latex, any one of the above-mentioned three monomer addition methods may be used. To produce a graft acrylic copolymer latex, a simple acrylic copolymer latex is used. In the presence, any of the above three methods of adding the monomers can be used.

The resin solid content of the acrylic copolymer latex is not particularly limited, as is the case with the simple or graft acrylic copolymer latex, but considering the productivity of the latex and the stability of the polymerization reaction, 10 to 60% by weight is preferred. The average resin particle size of the acrylic copolymer latex is preferably 0.01 to 1 μm, and more preferably 0.03 to 0.5 μm for both the simple or graft acrylic copolymer latex. If it is less than 0.01 μm, the impact resistance of the vinyl chloride resin tends to decrease, and if it exceeds 1 μm, both the impact resistance and the tensile strength decrease.

The acrylic copolymer latex according to the third aspect of the invention includes both simple or graft acrylic copolymer latex, and even if it is a simple acrylic copolymer latex, a predetermined amount of protection is required. When a colloid is added, a latex having excellent mechanical stability against stress can be obtained, and as a result, an effect comparable to the method for producing a vinyl chloride resin of the first invention and the second invention can be obtained.

The protective colloid to be added to the above acrylic copolymer latex is formed by further forming a hydrophilic protective colloid layer on the outer surface of the emulsifying dispersant layer on the surface of the latex particles, and mechanical stability of the latex. A polymer compound having a hydroxyl group, a carboxyl group, or an alkyl ether bond in its molecular chain, or a polymer compound whose molecular main chain is composed of oxyalkylene is preferably used.

Specifically, polyacrylic acid salts, α-alkyl acrylic acid salts, alkyl acrylate-acrylic acid salt copolymers, alkyl acrylate- (α-alkyl acrylic acid salt) copolymers, polymaleic acid, polymaleic acid salts. , Acrylic acid-maleic acid copolymer, acrylic acid-maleate copolymer, carboxylate-sulfonate copolymer, casein, caseinate, partially saponified polyvinyl acetate, polyethylene glycol, polymethyl vinyl ether , Polyethyl vinyl ether, methyl cellulose,
Ethyl cellulose, hydroxypropyl methyl cellulose and the like can be mentioned, preferably polyacrylate, α
-Alkyl acrylate, alkyl acrylate-acrylate copolymer, alkyl acrylate- (α-alkyl acrylate) copolymer, casein, caseinate,
Partial saponification products of polyvinyl acetate can be mentioned, and at least one of them can be used.

In the process of producing the acrylic copolymer latex, the timing and the number of times the protective colloid is added to the acrylic copolymer latex are not particularly limited, but during storage and transfer after the production of the latex. In order to ensure stability, it is preferable to add them all at once immediately after the polymerization. The method of addition is not particularly limited, but in order to rapidly disperse the protective colloid in the acrylic copolymer latex, the protective colloid is dissolved / diluted in water and mixed with stirring. It is preferable.

The amount of the protective colloid added to the acrylic copolymer latex is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 100 parts by weight based on 100 parts by weight of the solid content of the acrylic copolymer latex. 3 parts by weight. If it is less than 0.01 part by weight, sufficient mechanical stability of the latex cannot be obtained, and if it exceeds 10 parts by weight, the impact resistance of the obtained vinyl chloride resin becomes low.

In the method for producing a vinyl chloride resin according to the first, second and third inventions, the proportion of the acrylic copolymer (solid content of latex) in the vinyl chloride resin is particularly limited. However, it is preferably 1 to 30% by weight, and more preferably 4 to 20% by weight. If it is less than 1% by weight, sufficient impact resistance cannot be obtained and 3
If it exceeds 0% by weight, mechanical strength such as bending strength and tensile strength is lowered.

In the method of graft-copolymerizing vinyl chloride alone or a monomer containing vinyl chloride as a main component with an acrylic copolymer latex, the monomer containing vinyl chloride as the main component is 50% by weight or more of chloride. It means a mixture of vinyl 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, Examples thereof include vinyl fluoride and maleimide, and at least one of them can be used.

The method for graft-copolymerizing vinyl chloride alone or a monomer containing vinyl chloride as a main component with an acrylic copolymer latex is not particularly limited, but may be bulk polymerization, solution polymerization, The emulsion polymerization method and the suspension polymerization method are mentioned, but the suspension polymerization method is preferable in consideration of various physical properties such as economy and thermal stability of the obtained vinyl chloride resin. In the suspension polymerization method, a dispersant and an oil-soluble polymerization initiator are used, and during polymerization, a coagulant is added to the acrylic copolymer latex in order to reduce scale adhesion in the polymerization tank. It may be added.

Examples of the aggregating agent include polyvalent metal cations and quaternary ammonium compounds, and at least one of them can be used.

Examples of the polyvalent metal cation include metal salts of groups I, II and III of the periodic table, for example, sodium salts such as sodium chloride, sodium carbonate, sodium sulfate, sodium nitrate, sodium acetate and sodium phosphate. Potassium chloride, potassium carbonate, potassium sulfate,
Potassium salts such as potassium nitrate, potassium acetate, potassium phosphate; calcium salts such as calcium chloride, calcium carbonate, calcium sulfate, calcium nitrate, calcium acetate, calcium phosphate; magnesium chloride, magnesium carbonate, magnesium sulfate, magnesium nitrate, magnesium acetate, phosphoric acid Magnesium salts such as magnesium; aluminum salts such as aluminum chloride, aluminum carbonate, aluminum sulfate, aluminum nitrate, aluminum acetate, and aluminum phosphate.

Examples of the quaternary ammonium compound include ammonium salts of groups I, II and III of the periodic table, for example, ammonium salts such as ammonium chloride, ammonium carbonate, ammonium sulfate, ammonium nitrate, ammonium acetate and ammonium phosphate. Can be mentioned.

The dispersant is added for the purpose of improving the dispersion stability of the acrylic copolymer and effectively performing graft polymerization of vinyl chloride alone or a monomer containing vinyl chloride as a main component. (Meth) acrylic acid, (meth) acrylic acid salt-alkyl acrylate copolymer, methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, polyvinyl acetate and partial saponification products thereof, gelatin, polyvinylpyrrolidone, starch, maleic anhydride-styrene Examples thereof include copolymers, and at least one of them can be used.

The oil-soluble polymerization initiator is selected because the grafting efficiency of vinyl chloride to the acrylic copolymer is improved as compared with the water-soluble polymerization initiator. For example, lauroyl peroxide and t-butylperoxypivalate are selected. , Organic solvents such as diisopropyl peroxy dicarbonate, dioctyl peroxy dicarbonate, t-butyl peroxy neodecanoate, α-cumyl peroxy neodecanoate, 2,2-azobisisobutyronitrile, Examples thereof include azo compounds such as 2,2-azobis-2,4-dimethylvaleronitrile. Further, in the suspension polymerization method, a pH adjusting agent, an antioxidant and the like may be added as necessary.

As a specific example of the suspension polymerization method, pure water, an acrylic copolymer latex, a dispersant, an oil-soluble polymerization initiator and a water-soluble polymerization agent are placed in a pressure resistant reaction vessel equipped with a stirrer and a jacket. A viscous agent (protective colloid) and, if necessary, a polymerization regulator are added. 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 the 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 resin.

The degree of polymerization of the non-grafted vinyl chloride resin in the above vinyl chloride resin is 300 to 2000.
Is preferred, and more preferably 400-1400. When it is less than 300, the physical properties of the obtained vinyl chloride resin cannot be sufficiently obtained, and when it exceeds 2000, the fluidity at the time of molding is poor and various moldings are difficult.

The vinyl chloride resin according to the fourth aspect of the present invention is characterized in that
To a heat stabilizer, which is obtained by the production method according to claim 1 selected from claim 3 and, if necessary, at the time of molding.
Stabilization aids, lubricants, processing aids, antioxidants, light stabilizers,
Fillers, pigments, etc. are added.

Examples of the heat stabilizer include dimethyltin mercapto, dibutyltin mercapto, dioctyltin mercapto, dibutyltin malate, dibutyltin malate polymer, dioctyltin malate, dioctyltin malate polymer, dibutyltin laurate, dibutyltin laurate. Organotin stabilizers such as rate polymers, lead-based stabilizers such as lead stearate, dibasic lead phosphite and tribasic lead sulfate, calcium-
Examples thereof include zinc-based stabilizers, barium-zinc-based stabilizers, barium-cadmium-based stabilizers, and the like.
Seeds are used.

Examples of the stabilizing aid include epoxidized soybean oil, epoxidized linseed oil, epoxidized tetrahydrophthalate, epoxidized polybutadiene, and phosphoric acid ester, and at least one of them is used.
Examples of the lubricant include montanic acid wax, paraffin wax, polyethylene wax, stearic acid, stearyl alcohol, butyl stearate, and the like, and at least one of them is used.

Examples of the processing aid include acrylic processing aids which are alkyl acrylate-alkyl methacrylate copolymers having a weight average molecular weight of 100,000 to 2,000,000, and n-butyl acrylate-methyl methacrylate copolymer, 2 -Ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer and the like can be mentioned, and at least one of them is used.

Examples of antioxidants include phenolic antioxidants and the like. Examples of the light stabilizer include a salicylic acid ester-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorber, and a hindered amine-based light stabilizer, and at least one of these is used.

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.

A plasticizer may be added to the vinyl chloride resin for the purpose of improving the processability during molding, and examples thereof include dibutyl phthalate, di-2-ethylhexyl phthalate and di-2-ethylhexyl. Examples include adipate.

The above various additives may be mixed with the vinyl chloride resin by either hot blending or cold blending, and the molding method may be an extrusion molding method, an injection molding method, a calender molding method, a press molding method or the like. Can be mentioned.

(Function) When a polyfunctional monomer is graft-copolymerized on the acrylic copolymer latex, crosslinking of the acrylic copolymer latex is promoted, and at the same time, a hard crosslinked polymer layer is formed on the surface of the latex particles. Since the tackiness of the latex particles is reduced, the mechanical stability of the latex particles against stress such as stirring is remarkably improved, and it becomes difficult for the latex particles to coalesce and aggregate with each other.

As a result, the latex can be stably stored, transferred, and metered, and in the next step, vinyl chloride alone or the graft copolymerization of a vinyl monomer containing the vinyl chloride as a main component with the acrylic copolymer produces scale. Can be made to proceed uniformly and stably in an extremely small amount, the acrylic copolymer does not aggregate, and the composition remains as finely dispersed particles and is reactor-blended with vinyl chloride resin, resulting in impact resistance. It is presumed that the resin has excellent tensile strength.

Similarly, when a protective colloid is added to the acrylic copolymer latex, a hydrophilic protective colloid layer is further formed on the outer surface of the emulsifying dispersant layer on the surface of the latex particles, and the latex mechanical The stability was significantly improved, and an effect comparable to the graft copolymerization of the above-mentioned polyfunctional monomer was obtained.

[0052]

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

Examples 1 and 2 and Comparative Examples 1 to 3 1) Preparation of acrylic copolymer latex According to the composition shown in Table 1, a predetermined amount of pure water and an emulsifying dispersant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Product name "High Tenor N-0
8 "), n-butyl acrylate (hereinafter referred to as n-BA), 2-ethylhexyl acrylate (hereinafter referred to as 2-E)
HA) and trimethylolpropane triacrylate (hereinafter, TMPTA) were mixed and stirred to prepare an emulsified mixed monomer.

Next, pure water was placed in a reaction vessel equipped with a stirrer and a reflux condenser, the oxygen in the vessel was replaced with nitrogen, and the temperature of the reaction vessel was raised to 75 ° C. with stirring. After the heating is completed, the reaction container is charged with 30% of the emulsified mixed monomer prepared above.
% By weight was added all at once, and ammonium persulfate was added to initiate polymerization. Immediately after the completion of the polymerization, dropwise addition of the remaining emulsified mixed monomer was started. The dropping of all the emulsified mixed monomers was completed in 3 hours, followed by the prescribed amount of TMP.
TA was added dropwise again for 15 minutes. Further, heating and stirring were continued for 1 hour to complete the polymerization, and an acrylic polymer latex (hereinafter referred to as latex) having a solid content concentration of 30% by weight was obtained.

2) Synthesis of Vinyl Chloride Resin As shown in Table 1, 3% by weight of the latex and pure water of 1) and partially saponified polyvinyl acetate (trade name "Kuraray Poval L-8" manufactured by Kuraray Co., Ltd.) The aqueous solution, t-butyl peroxy neodecanoate, α-cumyl peroxy neodecanoate, and a flocculant were put into a reaction vessel equipped with a stirrer and a jacket all at once with stirring. Thereafter, the air in the polymerization vessel was discharged with a vacuum pump, and vinyl chloride was charged with stirring, and the polymerization was started by controlling the temperature of the reaction vessel at 57 ° C. When the pressure in the reaction vessel dropped to 7 kg / cm ² , the completion of the reaction was confirmed, and the reaction was stopped. After that, unreacted vinyl chloride monomer is removed,
Further, it was dehydrated and dried to obtain a vinyl chloride resin having a polymerization degree of about 1000 in the vinyl chloride resin.

Various physical properties of the latex and vinyl chloride resins in Examples 1 and 2 and Comparative Examples 1 to 3 were measured according to the evaluation methods described below. The results are shown in Table 1.

[0057]

[Table 1]

According to Table 1, when not graft-copolymerized with a polyfunctional monomer or the graft-copolymerization ratio is too low, the acrylic copolymer latex has poor mechanical stability and, conversely, a large amount. When it is a graft copolymer, it has excellent mechanical stability, but the impact resistance of the resulting vinyl chloride resin decreases.

Examples 3, 4 and Comparative Examples 5, 6, 1) Preparation of Acrylic Copolymer Latex According to the compounding composition shown in Table 2, a predetermined amount of pure water and an emulsifying dispersant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd. ) were prepared . , Trade name "Hitenol N-0
8 "), n-butyl acrylate (hereinafter referred to as n-BA), 2-ethylhexyl acrylate (hereinafter referred to as 2-E)
HA) and trimethylolpropane triacrylate (hereinafter, TMPTA) were mixed and stirred to prepare an emulsified mixed monomer.

Next, pure water was put into a reaction vessel equipped with a stirrer and a reflux condenser, the oxygen in the vessel was replaced with nitrogen, and the temperature of the reaction vessel was raised to 75 ° C. with stirring. After the heating is completed, the reaction container is charged with 30% of the emulsified mixed monomer prepared above.
% By weight was added all at once, and ammonium persulfate was added to initiate polymerization. Immediately after the completion of the polymerization, dropwise addition of the remaining emulsified mixed monomer was started. The dropping of all the emulsified mixed monomers was completed in 3 hours. Further, heating and stirring were continued for 1 hour to complete the polymerization, and an acrylic polymer latex (hereinafter referred to as latex) having a solid content concentration of 30% by weight was obtained. Next, sodium polyacrylate previously dissolved in pure water as a protective colloid (manufactured by Toagosei Co., Ltd.,
Product name "A-20P", hereinafter SPA) 0.01
A wt% aqueous solution was added to the resulting latex with slow stirring.

2) Synthesis of Vinyl Chloride Resin As shown in Table 2, 3 parts by weight of the latex of 1), pure water, and partially saponified polyvinyl acetate (Kuraray Co., Ltd., trade name “Kuraray Poval L-8”) % Aqueous solution, t-butyl peroxy neodecanoate, α-cumyl peroxy neodecanoate, and a flocculant were put into a reaction vessel equipped with a stirrer and a jacket all at once with stirring. Thereafter, the air in the polymerization vessel was discharged with a vacuum pump, and vinyl chloride was charged with stirring, and the polymerization was started by controlling the temperature of the reaction vessel at 57 ° C. The pressure in the reaction vessel is 7 kg / c
The reaction was stopped by confirming the completion of the reaction by the decrease to m ² . Then, unreacted vinyl chloride monomer was removed, and then dehydration and drying were performed to obtain a vinyl chloride resin having a polymerization degree of about 1000 in the vinyl chloride resin.

Example 5 According to the composition shown in Table 2, S was used as a protective colloid.
In the same manner as in Example 3 except that a 1% by weight aqueous solution of partially saponified polyvinyl acetate (saponification degree: about 70%, molecular weight: 700 to 800, hereinafter referred to as PVA) was used in place of PA. A vinyl chloride resin was obtained.

Comparative Example 4 A vinyl chloride resin was obtained in the same manner as in Example 3 except that no protective colloid was used according to the composition shown in Table 2.

The physical properties of the latex and vinyl chloride resin in Examples 3 to 5 and Comparative Examples 4 to 6 were measured according to the evaluation methods described below. The results are shown in Table 2.

[0065]

[Table 2]

According to Table 2, when the protective colloid is not added or is too small, the mechanical stability of the latex is poor, and when it is too large, the impact resistance of the vinyl chloride resin obtained cannot be obtained. .

Evaluation Method (Mechanical Stability of Latex) The mechanical stability of the latex was measured according to JIS K 6392. The acrylic copolymer latex was first adjusted to pH 6 with an aqueous sodium hydroxide solution, and then diluted with pure water so that the resin solid content of the latex was 20% by weight.
It was used as a measurement sample. Measurement temperature is 23 ℃, load is 10 kg,
The coagulation rate of the latex was calculated when the shear time was 10 minutes.

(Scale ratio) Calculated by the following formula from the scale weight w peeled off from the inner wall of the polymerization vessel, the stirring blade, the stirring blade main shaft, the baffle plate, etc. and the weight W of the obtained vinyl chloride resin. . Scale ratio (%) = (w / w + W) × 100

(Measurement of Fish Eye) 100 parts by weight of vinyl chloride resin, polyester adipate plasticizer 2
0 parts by weight, 0.5 parts by weight of anthraquinone type blue pigment, 0.6 parts by weight of barium-zinc type liquid stabilizer and 1 part by weight of organic epoxy type stabilizer were mixed, and this mixture was mixed with a roll kneader at 160 ° C. for 3 times. After kneading for 1 minute, 1 of the obtained sheet
The number of fish eyes present in an area of 0 × 10 cm was visually observed.

(Impact resistance) A Charpy impact test was conducted according to JI
The measurement temperature was 23 ° C. according to SK7111. The sample was roll-kneaded at 200 ° C. for 3 minutes with a resin composition prepared by mixing 0.5 part by weight of an organotin stabilizer and 1.0 part by weight of a montanic acid lubricant with 100 parts by weight of a vinyl chloride resin. , Thickness 3 obtained by press molding at 200 ° C for 3 minutes
mm. (Tensile strength) It was performed at a temperature of 23 ° C. according to JIS K7113. The sample was produced from the press plate used for the above Charpy impact test.

[0071]

Since the vinyl chloride resin and the method for producing the same of the present invention are constituted as described above, the acrylic copolymer latex has excellent mechanical stability, and the latex storage, transfer, metering, Graft polymerization of vinyl chlorides can be efficiently carried out, and the obtained vinyl chloride resin of the present invention has uniform quality and excellent impact resistance, weather resistance, tensile strength, etc. .

Claims (4)

[Claims] 1. A vinyl chloride resin characterized by graft-copolymerizing vinyl chloride alone or a vinyl monomer containing vinyl chloride as a main component with an acrylic copolymer latex obtained by graft-copolymerizing a polyfunctional monomer. Production method. 2. The acrylic copolymer latex is characterized by comprising 0.5 to 30 parts by weight of a polyfunctional monomer graft-copolymerized with 100 parts by weight of the acrylic copolymer. The method for producing a vinyl chloride resin according to claim 1. 3. A protective colloid is added in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the solid content of the acrylic copolymer latex, and the acrylic copolymer latex contains vinyl chloride alone or vinyl chloride as a main component. A method for producing a vinyl chloride-based resin, which comprises graft-copolymerizing a vinyl monomer as described above. 4. One selected from claim 1 to claim 3.
A vinyl chloride resin obtained by the production method described in the above item.