JPS6236412A - Production of vinyl chloride resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin excellent in impact resistance, weathering resistance and bending modulus, by graft-copolymerizing vinyl chloride with a copolymer comprising an alkyl (meth)acrylate, a monomer and a poly functional monomer. CONSTITUTION:An acrylic copolymer (A) is obtained by polymerizing 60-95wt% alkyl (meth)acrylate which can give a homopolymer of a secondary transition point <=-10 deg.C (e.g., n-butyl acrylate) with 5-39wt% monomer which can give a homopolymer of a secondary transition point >=0 deg.C (e.g., styrene) and 1-30wt% polyfunctional monomer (e.g., diallyl phthalate). 70-99pts.wt. vinyl chloride (B) is graft-copolymerized with 1-30pts.wt. component A in the presence of a radical polymerization initiator and, optionally, a dispersant and a chain transfer agent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a method for producing vinyl chloride resin. More specifically, this article relates to a method for producing vinyl chloride resin that has excellent impact resistance, weather resistance, and flexural modulus.

[Conventional technology]

Since vinyl chloride resin has excellent physical and mechanical properties, it has many uses as hard, semi-hard, and soft resins. However, when a vinyl chloride homopolymer is used for hard materials, it has the disadvantage of poor impact resistance and weather resistance. As a method to improve these drawbacks, polymer blends of vinyl chloride homopolymers and various elastomers can be mentioned.

Although this method can certainly improve the impact resistance, it has the disadvantage that the weather resistance 0 flexural modulus decreases.

A vinyl chloride graft copolymer obtained by graft copolymerizing vinyl chloride onto an alkyl acrylate polymer is known (Japanese Patent Publication No. 39-17067), and this vinyl chloride graft copolymer certainly has improved impact resistance. However, there was a drawback that the flexural modulus was insufficient. As described above, each of the methods known to date has advantages and disadvantages, and therefore their applications have been limited to some extent.

[Problem that the invention seeks to solve]

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

This led to the completion of the present invention.

That is, as a result of detailed studies on a method for obtaining a vinyl chloride resin with excellent impact resistance, weather resistance, and flexural modulus, the present inventors found that the secondary transition when made into a homopolymer Vinyl chloride is added to the copolymer of alkyl acrylate and/or alkyl methacrylate whose point is below 10°C, monomers whose secondary transition point when formed into a homopolymer is Q'O or above, and a polyfunctional polymer. The present inventors have discovered that it is possible to produce a vinyl chloride tree fertilizer with excellent impact resistance, weather resistance, and flexural modulus by graft copolymerizing. That is, the present invention provides homopoly,
When made into a homopolymer with 95 to 60% by weight of an alkyl acrylate and/or alkyl methacrylate whose secondary transition point is 110°C or less, the secondary transition point is 0°C or higher. Copolymer obtained by copolymerizing monomers with a weight range of 5 to 39 and a polyfunctional monomer with a weight range of 1 to 30 (hereinafter referred to as acrylic copolymer) 1
This is a method for producing a vinyl chloride resin having excellent impact resistance, weather resistance, and flexural modulus, which is characterized by graft copolymerizing 99 to 70 parts by weight of vinyl chloride to 30 parts by weight.

The alkyl acrylates and alkyl methacrylates used in the present invention have a secondary transition point of 110'C or less when made into a homopolymer, for example,
Ethyl acrylate, n-propyl acrylate, iso-butyl acrylate.

n-butyl acrylate, n-hexyl acrylate,
Examples include 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate and n-octyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate, and lauryl methacrylate. These alkyl acrylates and alkyl methacrylates act as soft segments of the copolymer and provide excellent impact resistance, and the amount used is 95 to 6
If it exceeds 95 weight percent, no improvement in the flexural modulus can be expected, and if it is less than 60 weight percent, the impact resistance will decrease, so it is preferable.

Therefore, for example, aromatic vinyls such as styrene, α-methylstyrene, and vinyltoluene, unsaturated nitrites such as acrylonitrile and methacrylate, vinyl acetate,
Examples include vinyl esters such as vinyl propionate, butyl vinyl ether, octyl biacrylates, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and propyl methacrylate, which may be used alone or in combination of two or more. These monomers function as hard segments by copolymerizing, and the amount used is preferably 5 to 39% by weight; if it is less than 5% by weight, no improvement in the flexural modulus can be expected;
If it exceeds 9% by weight, impact resistance decreases, which is not preferable. Especially when adjusting the bending elastic modulus, methyl methacrylate, methyl acrylate, acrylonitrile,
Styrene is preferred.

The polyfunctional monomer used in the present invention is a polyfunctional monomer that causes crosslinking etc. to alkyl acrylate and/or alkyl methacrylate, such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, etc. Glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1.8-propylene glycol dimethacrylate), 1.8-butylene glycol dimethacrylate, 1.4-butylene glycol dimethacrylate, etc. Examples include polyalkylene glycol acrylates or methacrylates, di- or triallyl compounds such as diallyl phthalate, diallyl maleate, diallyl fumarate, diallyl succinate, and divinylbenzene. The amount of the polyfunctional monomer to be used is preferably 1 to 30% by weight, and if it is less than 1% by weight, no improvement in the flexural modulus can be expected, and if it exceeds 30% by weight, the impact resistance will decrease, so it is preferable. do not have.

The copolymer can be obtained by a polymerization method such as emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization using a generally known emulsifier, dispersant, catalyst, etc., but emulsion polymerization is particularly preferred. To obtain a copolymer by a general emulsion polymerization method, for example, a pure water anionic emulsifier and a water-soluble polymerization catalyst are placed in a jacketed polymerization reactor, the air inside the can is removed, and then the alkyl acrylate and/or Alternatively, alkyl methacrylate, monomers, and polyfunctional monomers are charged, and after emulsification, the inside of the can is heated by a heat medium in a jacket to initiate a copolymerization reaction. The copolymerization reaction is an exothermic reaction, and the internal temperature is controlled by a heating medium in the jacket as necessary. After the reaction is completed, unreacted monomers are removed from the can to obtain the acrylic copolymer of the present invention. The method of charging into the polymerization reactor is not particularly limited. Further, if necessary, a particle size adjusting agent for the acrylic copolymer, a decomposition accelerator for the catalyst, etc. may be added to control the copolymerization reaction.

The appropriate amount of the acrylic copolymer used as the backbone polymer for graft copolymerization is 1 to 30 parts by weight based on 100 parts by weight of the total amount of chloride and nil monomers. If the amount of the acrylic copolymer used is less than 1 part by weight, the impact resistance will not be sufficient, and if it exceeds 30 parts by weight, the impact resistance will improve, but the flexural modulus will decrease, which is not preferable.

The graft copolymerization method of the present invention includes an aqueous suspension polymerization method,
Examples include an aqueous emulsion polymerization method, a solution polymerization method, and a solventless polymerization method, but it is preferable to employ an aqueous suspension polymerization method.

When carrying out the aqueous suspension polymerization method, the weight ratio of the total amount of the acrylic copolymer of the long-stem polymer and the vinyl chloride monomer to water is 1:1 to 1:5, preferably 1:1 to 1:8. be. In the general method of graft copolymerization using suspension polymerization, pure water, a suspension stabilizer such as hydroxypropyl methyl cellulose,
Add a radical polymerization initiator and, if necessary, a degree of polymerization reducer, add the acrylic copolymer and suspend it, then remove the air in the can, and then add vinyl chloride along with other vinyl compounds as necessary. Charge. Thereafter, the inside of the can is heated by the heat medium inside the jacket, the acrylic copolymer is dissolved in the vinyl chloride, and graft copolymerization is started. Graft copolymerization is an exothermic reaction, and if necessary, the internal temperature is controlled by a heat medium inside the jacket. After the reaction is completed, unreacted vinyl chloride is removed from the outside of the can, and graft copolymerization is carried out in the form of a slurry. Obtain vinyl chloride resin. The slurry is dehydrated and dried according to a conventional method to obtain a graft copolymer resin. The charging method to the polymerization reactor is not limited, and among the charged raw materials such as pure water, suspension stabilizer, acrylic copolymer, and vinyl chloride, the acrylic copolymer may be replaced with vinyl chloride. A method of melting and charging is also adopted.

In graft copolymerization, other monomers may be present in the coexistence within a range that reduces impact resistance, weather resistance, and flexural modulus.

In carrying out the present invention, it is advantageous to carry out the graft copolymerization by a radical polymerization method, and the radical polymerization initiators used for this purpose include lauroyl peroxide, tertiary-gyl peroxy pivalate, diimpropyl peroxy Organic peroxides such as dicarbonate and dioctyl peroxydicarbonate, 2.2'
Examples include oil-soluble polymerization initiators of azo compounds such as -azohisisobutyronitrile 2 and 27-azobis-2°4-dimethylvaleronitrile, and water-soluble polymerization initiators such as potassium persulfate and ammonium persulfate.

The amount of these polymerization initiators used is preferably 0.005 to 1.0 parts by weight per 100 parts by weight of vinyl chloride resin.

Dispersants include methylcellulose, ethylcellulose, hydroxyglobil methylcellulose, hydroxyethylcellulose, polyvinyl alcohol and its partially saponified products, gelatin-poly11 rubirolidone, organic substances such as starch, or inorganic substances such as magnesium carbonate, calcium carbonate, and calcium phosphate. are used alone or in combination, and the amount added is 0.00 parts by weight per 100 parts by weight of vinyl chloride.
01 to 1.0 parts by weight.

Furthermore, the present invention uses a chain transfer agent, such as 2-mercaptoethanol, which is used in the conventional method of polymerizing vinyl monomers, in an amount of 0.0% per 100 parts by weight of vinyl chloride resin.
01 to 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, lubricant, processing aid, antioxidant, filler, ultraviolet absorber, and By blending pigments and the like, it is possible to carry out normal molding processes, and it is suitably used for building materials, etc., taking advantage of its excellent properties such as impact resistance, weather resistance, and mechanical strength.

The present invention will be specifically explained below with reference to Examples. A polymerization machine with an internal volume of 7 mm equipped with a stirring blade was charged with deionized water,
An acrylic copolymer having the composition shown in Table 1, a dispersant, a polymerization initiator, etc. were charged, and after removing the air inside with a vacuum pump, vinyl chloride was charged and polymerization was carried out. Thereafter, 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. To 100 parts of the obtained graft copolymer resin, 2 parts of tribasic lead sulfate, 1 part of dibasic lead stearate, and Stair 'J:' [lead 1.5
Mix the parts uniformly and then roll with a hot roll at 30'O.
A sheet was prepared by kneading for 5 minutes and pressing at 130° C. for 5 minutes, and samples taken from this sheet were measured for Charpy impact strength and weather resistance 0 flexural modulus as follows. The results are shown in Tables 1 and 2.

Charpy impact strength: JI8 K- (5745 flexural modulus: JI8 K-6740) Weather resistance: Irradiation for 200 hours with a carbon arc sunshine weatherometer (spray 12760 minutes, black panel 68°C), color change comparison.

Comparative Example-9 Polymerization was carried out under pressure 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 an acrylic impact-resistant agent (composition: 75 parts of n-butyl acrylate, 20% of methyl acrylate, 5% of acrylonitrile) and 2 parts of tribasic lead sulfate were added.

1 part of dibasic lead stearate and 1.5 parts of lead stearate were 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.

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

〔Effect of the invention〕

As explained in detail above, according to the method of the present invention, a vinyl chloride resin having excellent impact resistance and weather resistance, improved flexural modulus, and well-balanced physical properties can be obtained.

Claims (1)

[Claims] 60 to 95% by weight of alkyl acrylate and/or alkyl methacrylate having a secondary transition point of -10°C or lower when formed into a homopolymer, and 5 to 95% of monomers having a secondary transition point of 0°C or higher when formed into a homopolymer. A method for producing a vinyl chloride resin, which comprises graft copolymerizing 70 to 99 parts by weight of vinyl chloride to 1 to 30 parts by weight of a copolymer of 39% by weight and 1 to 30% by weight of a polyfunctional monomer.