JPH0635498B2 - Method for producing vinyl chloride resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a vinyl chloride resin. More specifically, it relates to a method for producing a vinyl chloride resin excellent in impact resistance, weather resistance and flexural modulus.

[Conventional technology]

Since vinyl chloride resin has excellent physical and mechanical properties, it has many uses as a resin for hard, semi-hard, and soft materials. However, when a vinyl chloride homopolymer is used for hard materials, it has the drawback of being inferior in impact resistance and weather resistance. As a method for improving these drawbacks, a polymer blend of a vinyl chloride homopolymer and various elastic bodies can be mentioned. Although this method can certainly improve the impact resistance, it has a defect that the weather resistance and the flexural modulus are decreased.

A vinyl chloride graft copolymer obtained by graft-copolymerizing vinyl chloride with an alkyl acrylate polymer is known (Japanese Patent Publication No. 39-17067). This vinyl chloride graft copolymer is certainly improved in impact resistance. However, there was a drawback that the flexural modulus was not sufficient. As described above, each of the methods known to date has advantages and disadvantages, and therefore the applications have been limited to some extent.

[Problems to be solved by the invention]

An object of the present invention is to provide a method for obtaining a vinyl chloride resin having excellent impact resistance, weather resistance, and improved flexural modulus and well-balanced physical properties.

[Means for solving problems]

The inventors of the present invention have conducted intensive studies to solve the above problems and completed the present invention.

That is, the present inventors have conducted a detailed study on a method for obtaining a vinyl chloride resin excellent in impact resistance, weather resistance and flexural modulus, and as a result, the secondary transition point when a homopolymer is obtained. With a vinyl chloride graft copolymer to a copolymer of an alkyl acrylate and / or an alkyl methacrylate having a temperature of −10 ° C. or lower, and a specific monomer having a secondary transition point of 0 ° C. or higher when formed into a homopolymer and a polyfunctional monomer. It has been found that a vinyl chloride resin having excellent impact resistance and weather resistance and an excellent flexural modulus can be produced by polymerization, and the present invention has been completed. That is, when the present invention is a homopolymer, the secondary transition point of the alkyl acrylate and / or alkyl methacrylate of which the secondary transition point is −10 ° C. or lower is 95 to 60% by weight, and the secondary transition point of the homopolymer is 0 ° C. At least 5 to 39% by weight of at least one monomer selected from the group consisting of α-methylstyrene, vinyltoluene, unsaturated nitriles, vinyl ethers, alkyl acrylates and alkyl methacrylates, and 1 to 30% by weight of polyfunctional monomers. % Copolymers (hereinafter referred to as “acrylic copolymers”) 1-3
A method for producing a vinyl chloride resin excellent in impact resistance, weather resistance and flexural modulus, characterized by graft-copolymerizing 99 to 70 parts by weight of vinyl chloride with respect to 0 part by weight.

The alkyl acrylate and alkyl methacrylate used in the present invention have a secondary transition point of −10 ° C. or lower when formed into a homopolymer, and include, for example,
Ethyl acrylate, n-propyl acrylate, iso-butyl acrylate, n-butyl acrylate, n-
Hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate and n-octyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate, lauryl methacrylate and the like can be mentioned. These alkyl acrylates and alkyl methacrylates act as soft segments of the copolymer to impart excellent impact resistance, and the amount used is preferably 95 to 60% by weight, and when it exceeds 95% by weight, the flexural modulus is improved. Can not be expected, 60% by weight
When it is less than 1, the impact resistance is lowered, which is not preferable.

The specific monomer used in the present invention has a second-order transition point of 0 ° C. or higher when formed into a homopolymer, and α-
Aromatic vinyls such as methylstyrene and vinyltoluene, unsaturated nitriles such as acrylonitrile and methacrylonitrile, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as butyl vinyl ether, octyl vinyl ether and lauryl vinyl ether, methyl Monomers selected from the group consisting of alkyl acrylates such as acrylates, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and propyl methacrylate are used alone or in combination of two or more. These monomers work as a hard segment by copolymerization, and the amount used is preferably 5 to 39% by weight, and when less than 5% by weight,
If the flexural modulus cannot be improved and if it exceeds 39% by weight,
It is not preferable because the impact resistance is lowered. In particular, when adjusting the flexural modulus, methyl methacrylate, methyl acrylate, and acrylonitrile are suitable.

The polyfunctional monomer used in the present invention is a polyfunctional monomer that causes crosslinking or the like in alkyl acrylate and / or alkyl methacrylate, and examples thereof include ethylene glycol diacrylate, diethylene glycol diacrylate, and triethylene glycol diacrylate. Of mono- or polyalkylene glycols such as acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate Acrylate or methacrylates, diallyl phthalate, diallyl malate, diallyl fumarate, diallyl succinate, etc. Di- or triallyl compounds and divinylbenzene and the like. The amount of the polyfunctional monomer to be used is preferably 1 to 30% by weight. If it is less than 1% by weight, the flexural modulus cannot be expected to be improved, and if it exceeds 30% by weight, the impact resistance is lowered, which is not preferable.

The alkyl acrylate and / or alkyl methacrylate used in the present invention, the above-mentioned monomers, and polyfunctional monomers are copolymerized by emulsion polymerization, suspension polymerization, using a generally known emulsifier, dispersant, catalyst, etc. It can be obtained by a polymerization method such as solution polymerization or bulk polymerization, but emulsion polymerization is particularly preferable. As a method for obtaining a copolymer by a general emulsion polymerization method, for example, pure water, an anionic emulsifier and a water-soluble polymerization catalyst are put in a polymerization reactor with a jacket, air in the can is eliminated, and then an alkyl Acrylate and /
Alternatively, the alkyl methacrylate, the above-mentioned monomers and polyfunctional monomers are charged, and after emulsification, the inside of the can is heated by the heating medium in the jacket to start the copolymerization reaction. The copolymerization reaction is an exothermic reaction, and if necessary, the internal temperature is controlled by the heat medium in the jacket. After completion of the reaction, unreacted monomers are removed from the can to obtain the acrylic copolymer of the present invention. The charging method into the polymerization reactor is not particularly limited. If necessary, a particle size adjusting agent for the acrylic copolymer and a catalyst decomposition accelerator for controlling the copolymerization reaction may be added.

The amount of the acrylic copolymer used as the trunk polymer for the graft copolymerization is appropriately 1 to 30 parts by weight per 100 parts by weight of the total amount including the amount of the vinyl chloride monomer used. If the amount of the acrylic copolymer used is less than 1 part by weight, the impact resistance is insufficient, and if it exceeds 30 parts by weight, the impact resistance is improved but the flexural modulus is lowered, which is not preferable.

As the graft copolymerization method of the present invention, an aqueous suspension polymerization method,
Examples of the aqueous emulsion polymerization method, solution polymerization method, solventless polymerization method and the like are preferable, and the aqueous suspension polymerization method is preferably adopted.

When carrying out the aqueous suspension polymerization method, the weight ratio of the total amount of the acrylic copolymer of the multi-stem polymer, the vinyl chloride monomer and water is 1: 1 to 1: 5, preferably 1: 1 to 1: 8. is there. The method of graft copolymerization copolymerization by a general suspension polymerization method is, for example, pure water, a suspension stabilizer such as hydroxypropylmethylcellulose, a radical polymerization initiator, and if necessary, in a polymerization reactor with a jacket. Put a polymerization degree lowering agent, suspend the acrylic copolymer by adding it,
The air in the can is then evacuated and then vinyl chloride is charged, optionally with other vinyl compounds. After that, the inside of the can is heated by the heating medium in the jacket, the acrylic copolymer is dissolved in vinyl chlorides, and the graft copolymerization is started. Graft copolymerization is an exothermic reaction, and the internal temperature is controlled by a heating medium in the jacket, if necessary. After completion of the reaction, unreacted vinyl chloride is removed outside the can to obtain a slurry-like graft copolymerized vinyl chloride resin. The slurry is dehydrated and dried according to a conventional method to obtain a graft copolymer resin. Also, the charging method to the polymerization reactor is not limited, and among the charging materials such as pure water, suspension stabilizer, acrylic copolymer and vinyl chloride, the acrylic copolymer is changed to vinyl chloride. A method of melting and charging is also adopted.

In the graft copolymerization, other monomers may coexist as long as the impact resistance, weather resistance and flexural modulus are not reduced.

In carrying out the present invention, the graft copolymerization is advantageously carried out by a radical polymerization method, and as the radical polymerization initiator used for that purpose, lauroyl peroxide, tert-butyl peroxypivalate, diisopropyl peroxydiene is used. Organic peroxides such as carbonate and dioctyl peroxydicarbonate, 2,
Examples thereof include oil-soluble polymerization initiators of azo compounds such as 2'-azohisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile, and water-soluble polymerization initiators such as potassium persulfate and ammonium persulfate. To be The amount of these polymerization initiators used is preferably 0.005 to 1.0 part by weight per 100 parts by weight of the vinyl chloride resin.

Examples of the dispersant include methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxymethyl cellulose, polyvinyl alcohol and partially saponified products thereof, gelatin, polyvinylpyrrolidone, organic substances such as starch, magnesium carbonate, calcium carbonate,
Inorganic substances such as calcium phosphate are used alone or in combination, and the addition amount thereof is 0. 0 with respect to 100 parts by weight of vinyl chloride.
01-1.0 parts by weight.

Furthermore, the present invention provides a chain transfer agent, such as 2 mercaptoethanol, used in the conventional method for polymerizing vinyl monomers in an amount of 0.001 per 100 parts by weight of vinyl chloride resin.
~ 1.0 parts by weight may be added.

The graft-copolymerized vinyl chloride resin obtained by the method of the present invention has the usual thermal stability, lubricants, processing aids, antioxidants, fillers, ultraviolet absorbers, used for molding conventional vinyl chloride resins, By adding a pigment or the like, it is possible to carry out a usual molding process, and it is suitably used for a building material or the like by taking advantage of the characteristics excellent in impact resistance, weather resistance and mechanical strength.

Hereinafter, the present invention will be described in detail with reference to examples, but the parts shown in the examples are parts by weight.

〔Example〕

A polymerizer having an inner volume of 7m ³ equipped with Example 1 through Example -6 Comparative Example -1-8 stirring blades, deionized water,
An acrylic copolymer having the composition shown in Table 1, a dispersant, a polymerization initiator and the like were charged, the air inside was removed by a vacuum pump, and then vinyl chloride was charged to carry out polymerization. Then, vinyl chloride was removed, and the contents were filtered and dried to obtain a white powder. The vinyl chloride component of this powder was measured. Tribasic lead sulfate 2 was added to 100 parts of the obtained graft copolymer resin.
Parts, dibasic lead stearate 1 part, lead stearate 1.5
Parts were mixed uniformly, further kneaded with a hot roll at 180 ° C for 5 minutes, and pressed at 180 ° C for 5 minutes to prepare a sheet, and the samples taken from this sheet were subjected to sheary impact strength, weather resistance, and flexural modulus. Was measured as follows. The results are shown in Tables 1 and 2.

Shearpy impact strength: JIS K-6745 Bending elastic modulus: JIS K-6740 Weather resistance: Carbon arc sun shear in weather meter (spray 12/60 minutes, black panel 63 ° C) irradiation for 200 hours, comparison of discoloration.

Comparative Example-9 Polymerization was performed in the same manner as in Example-1 except that the acrylic resin was not charged in Example-1, and the results shown in Table 2 were obtained. To 100 parts of this resin, 15 parts of acrylic impact modifier (composition n-butyl acrylate 75%, methyl acrylate 20%, acrylonitrile 5%), tribasic lead sulfate 2 parts, dibasic lead stearate 1 part, stearin 1.5 parts of lead acid was uniformly mixed, a sheet was prepared in the same manner as in Example-1, and the physical properties were measured. The results are shown in Table 2.

From the above results, it is clear that the vinyl chloride resin by graft copolymerization of the present invention is extremely excellent in impact resistance, weather resistance and mechanical strength.

[Effects of the Invention] As described in detail above, according to the method of the present invention, it is possible to obtain a vinyl chloride resin having excellent physical properties and excellent impact resistance and weather resistance, and improved flexural modulus. it can.

Claims (1)

[Claims] 1. A homopolymer having a second-order transition point of -1.
Alkyl acrylate and / or alkyl methacrylate having a temperature of 0 ° C. or lower and 60 to 95% by weight and a secondary transition point of a homopolymer of 0 ° C. or higher, α-methylstyrene, vinyltoluene, unsaturated nitriles, vinyl ethers Copolymer of 5 to 39% by weight of at least one monomer selected from the group consisting of alkyl acrylates and alkyl methacrylates and 1 to 30% by weight of a polyfunctional monomer and 1 to 30 parts by weight of vinyl chloride and 70 to 50% of vinyl chloride. A method for producing a vinyl chloride resin, which comprises graft-copolymerizing 99 parts by weight.