JPH089642B2 - Method for producing matte vinyl chloride polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a molding material such as packing, sheet and tube, which is required to have a matt property, and has a vinyl chloride-based material with improved initial color resistance and thermal stability. The present invention relates to a method for producing a polymer.

(Prior art) Conventionally, vinyl chloride resin is prone to thermal deterioration during processing, and in order to prevent this, it is processed by blending a Sn-based or Pb-based stabilizer or by blending an epoxy resin for processing. The means is adopted. A method has also been proposed in which an epoxy resin is added and polymerized to improve both the thermal stability and initial color resistance of the vinyl chloride resin.

(Problems to be solved by the invention) However, the epoxy resin used in this method cannot completely prevent coloring due to heat in the step of removing unreacted monomers, and the color originally possessed by this epoxy resin However, there is a problem that the initial color fastness is deteriorated. On the other hand, in the case of matting vinyl chloride-based polymers that contain gel components in the conventional components, development efforts are focused on improving the matting effect, improving the creep characteristics, etc., and improving thermal stability and initial color resistance. The improvement of sex was not neglected. However, the effect of recent application development and the problem of coloring in films and the like are becoming more important.

That is, an object of the present invention is to provide a method for producing a matte vinyl chloride polymer containing a gel component which has improved thermal stability and initial color resistance.

(Means for Solving the Problems) As a result of intensive studies to solve these problems, the present inventors have found that a vinyl chloride monomer or a vinyl-based monomer mixture mainly containing vinyl chloride is used as an aqueous medium. During suspension polymerization in (A) a polyfunctional monomer containing two or more ethylenic double bonds in the molecule, and (B) a general formula I: (Here R ¹ is _{-O -, - CH 2 -,} - CH 2 -CH 2 -, or Alternatively, the general formula II: (Here, R ² is —O—, —CH ₂ —, Polymerization in the presence of an epoxy resin represented by the formula (1) gives a glossy vinyl chloride polymer with improved thermal stability and initial color fastness. The gel content insoluble in 5 to 90% by weight, preferably 10 to 50% by weight, is effectively exhibited. Particularly, when it is less than 5% by weight, the matting property is poor and, conversely, 90% by weight. The present invention has been completed based on the finding that the workability becomes inferior when the content exceeds 10% by weight.

Explaining this, as the polyfunctional monomer used in the present invention, diallyl isophthalate, diallyl esters of phthalic acid such as diallyl terephthalate; diallyl maleate, diallyl fumarate, diallyl itaconate, divinyl itaconate, Diallyl and divinyl esters of ethylenically unsaturated dibasic acids such as divinyl fumarate; diallyl and divinyl esters of saturated dibasic acids such as diallyl adipate, divinyl azimate, diallyl azelate, diallyl sebacate; diallyl ethers, triallyl shea Divinyl ethers such as nurate, triallyl isocyanurate, triallyl trimellitate and ethylene glycol divinyl ether, n-butanediol divinyl ether, octadecane divinyl ether; Vinyl and allyl esters of acrylic acid and methacrylic acid such as vinyl acetate, vinyl methacrylate, allyl acrylate, allyl methacrylate; ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, Diacrylic and dimethacrylic esters of polyhydric alcohols such as polyethylene glycol diacrylate;
Triacryl and trimethacryl esters of polyhydric alcohols such as trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate: bismethacryloyloxyethylene phthalate, 1 1,3,5-triacryloylhexahydrotriazine and 1,2-butadiene homopolymer such as unsaturated bond-containing low molecular weight polymers;
These may be used alone or in combination of two or more.

The amount of the polyfunctional monomer used is preferably 0.1 to 10% by weight with respect to the vinyl chloride-based polymer, and as the addition method, the whole amount may be added all at once or may be added in small amounts continuously. Good. Further, the timing may be either before the initiation of polymerization or during the polymerization.

On the other hand, the epoxy resins represented by the general formulas I and II are different from the general epoxy resins such as bisphenol A type epoxy resin, novolac type epoxy resin, polyglycol type epoxy resin, etc. There are few. It is considered that this is because the benzene ring in the resin is hydrogenated, and from the viewpoint of heat resistance, an epoxy resin having this hydrogenated benzene ring, such as hexahydroisophthalic acid glycidyl ester, 1 , 3-bis (N, N-diglycidylaminomethyl)
Cyclohexane and the like are preferable.

The amount of the epoxy resin added is 0.1 to 10 parts by weight, preferably 0.3 to 8 parts by weight, based on 100 parts by weight of the vinyl chloride monomer or a mixture of vinyl monomers mainly containing vinyl chloride. If it is less than 10 parts by weight, the effect of improving the thermal stability is not sufficient, and if it exceeds 10 parts by weight, the effect of improving the thermal stability is not improved in proportion to the increase of the amount, which is not economical.
The method of addition is not particularly limited, such as a liquid as it is or diluted with a solvent, and a solid may be dissolved in a solvent or the like and used. Further, the addition time may be before the initiation of polymerization, during the polymerization, or in the polymer slurry immediately before the recovery of the unreacted monomer.

In the method for producing a vinyl chloride resin composition according to the present invention, a polymer raw material applied to the vinyl chloride resin composition is a mixture of vinyl chloride monomer and vinyl chloride-based copolymerizable vinyl monomer. Vinyl chloride is 50% by weight or more), and as the comonomer to be copolymerized with vinyl chloride, vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid esters such as methyl acrylate and ethyl acrylate or methacrylic Acid esters; olefins such as ethylene and propylene; maleic anhydride;
Acrylonitrile; styrene; vinylidene chloride; and other monomers copolymerizable with vinyl chloride.

Suspension polymerization in an aqueous medium according to the present invention using these monomers is a dispersion aid usually used in the polymerization of vinyl chloride in an aqueous medium, such as methyl cellulose,
Water-soluble cellulose ethers such as hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose; partially saponified polyvinyl alcohol; acrylic acid polymers; water-soluble polymers such as gelatin; sorbitan monolaurate, sorbitan trioleate, glycerin tristearate, ethylene oxide propylene. Oil-soluble emulsifiers such as oxide block copolymers; water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate, and sodium laurate may be used alone or in combination of two or more.

Other conditions in this polymerization, aqueous medium to the polymerization vessel,
The vinyl chloride monomer, and optionally other comonomers, dispersion aids, polymerization initiators, etc. may be charged in the same manner as in the past, and the same may be applied to the polymerization conditions such as the ratio of these charged monomers and the polymerization temperature. .

Therefore, the polymerization initiator used for this polymerization may also be one that has been conventionally used for vinyl chloride-based polymerization, for example, diisopropyl peroxydicarbonate,
Percarbonate compounds such as di-2-ethylhexyl peroxydicarbonate and diethoxyethyl peroxydicarbonate; t-butyl peroxypivalate,
Perester compounds such as t-hexylperoxypivalate, t-butylperoxyneodecanate, α-cumylperoxyneodecanate; acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxy Peroxides such as phenoxyacetate and 3,5,5-trimethylhexanoyl peroxide; azobis-2,4-dimethylvaleronitrile, azobis (4
-Methoxy-2,4-dimethylvaleronitrile) and the like; and azo compounds such as potassium persulfate, ammonium persulfate and hydrogen peroxide, which can be used alone or in combination of two or more.

Further, in this polymerization system, a polymerization degree adjusting agent, a chain transfer agent, a pH adjusting agent, a gelation improving agent, an antistatic agent, an antioxidant, an anti-scale agent, which are appropriately used for vinyl chloride-based polymerization, if necessary. It is also optional to add such as.

(Examples) Hereinafter, specific embodiments of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Examples 1 to 4. A stainless steel polymerization vessel having an internal volume of 130 was charged with 6 parts of deionized water.
0kg, partially saponified polyvinyl alcohol 30g, di-2-
15 g of ethylhexyl peroxydicarbonate, charged with polyfunctional monomer and epoxy resin of the type and amount shown in the table, degassed the inside of the vessel to 100 mmHg, and charged 30 kg of vinyl chloride monomer. It is. While stirring the inside of the vessel, hot water was passed through the jacket to raise the temperature to 57 ° C, and the polymerization was continued while maintaining the temperature. The reaction was stopped when the pressure in the polymerization vessel dropped to 6.0 kg / cm ² G, and the unreacted monomer was recovered. The polymer slurry was taken out of the container and dehydrated and dried to obtain a vinyl chloride polymer.

Comparative Example 1. A vinyl chloride polymer was obtained in the same manner as in the previous example except that the epoxy resin was not used.

Comparative Examples 2-4. A vinyl chloride polymer was obtained in the same manner as in Example 1, except that an epoxy resin other than the one targeted by the present invention was used.

For each vinyl chloride polymer obtained in each of the above Examples and Comparative Examples, insoluble gel content of the polymer by the following method,
Thermal stability and initial colorability were measured, and these results are also shown in the table.

(Measurement method of insoluble gel content) 1 g of each vinyl chloride polymer was added to tetrahydrofuran (TH
F) Put in 100 ml and mix well while heating to 60 ° C. After stirring and heating were stopped and the mixture was allowed to stand for 24 hours, 10 ml of the supernatant liquid was taken, the liquid was evaporated to dryness, the amount of the polymer in the residue was weighed, and the value is used to calculate from the following formula.

(Test method for thermal stability and initial colorability) Vinyl chloride polymer 100 parts by weight Impact modifier B-22 (manufactured by Kaneka) 8 〃 Epoxidized soybean oil 6 〃 Calcium stearate 0.1 〃 Hex succinate 0.3 〃 Lubricant (Hoechst Wax PE-190) 0.2〃, knead with a test roll at 180 ℃ for 5 minutes,
A sheet having a thickness of 0.5 mm was prepared, and the sheet was placed in a Gear's oven, and the time (minute) until it was completely blackened at a temperature of 170 ° C. was measured and used as the value of thermal stability.

The initial colorability of the 0.5 mm thick sheet is 160 ° C.
It was pressed for 10 minutes to form a transparent test piece having a thickness of 5 mm, which was visually compared with Comparative Example 1 as a reference.

(Effects of the Invention) According to the present invention, a matte vinyl chloride polymer having improved initial colorability and thermal stability can be obtained.

Claims (1)

[Claims] 1. When a suspension polymerization of a vinyl chloride monomer or a mixture of vinyl monomers mainly composed of vinyl chloride is carried out in an aqueous medium, (A) an ethylenic double bond in the molecule A polyfunctional monomer having one or more, and (B) the general formula I: (Here R ¹ is _{-O -, - CH 2 -,} - CH 2 -CH 2 -, or Alternatively, the general formula II: (Here, R ² is —O—, —CH ₂ —, The method for producing a matte vinyl chloride polymer is characterized by polymerizing in the presence of an epoxy resin represented by