JPS6123925B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a polyvinyl chloride resin molded product with an adjusted specific gravity that does not reduce the strength and durability of the molded product by adding powdered inorganic micro hollow spheres treated with a silane coupling agent before or during polymerization. The present invention relates to a method for producing a vinyl chloride resin composition. In recent years, research has been carried out in various fields to impart functions such as mechanical strength and heat resistance by combining inorganic and organic powder fillers with thermoplastic resins, and some have already been put into practical use. Regarding polyvinyl chloride resin, we can increase the amount (reduce cost), adjust the specific gravity, color, add conductivity,
Various fillers are used for purposes such as reinforcing effects. Silica, clay, talc, calcium carbonate, titanium oxide, alumina, and their microscopic hollow spheres as weight increasing and specific gravity adjusting agents; carbon black, calcium carbonate, titanium oxide, etc. as coloring agents; carbon as an antistatic agent to provide electrical conductivity. Black: Glass fiber, talc, etc. are used to stop elongation and increase the reinforcing effect. These methods of use generally involve mixing the polyvinyl chloride resin, filler, and necessary stabilizers, lubricants, plasticizers, etc. in a mixer. If the compound is mixed for a long time in order to sufficiently disperse the filler, the thermal stability of the compound decreases, and the resulting molded product is not only discolored but also heavily colored and has poor marketability. Furthermore, when adjusting the specific gravity of the compound using inorganic microscopic hollow spheres, the microscopic hollow spheres are destroyed in the mixer, making it impossible to obtain a sufficiently lightweight compound. If mixing in the mixer is not sufficient, not only will the filler fail to perform its intended function, but it will also cause roughening of the surface of the molded product and a decrease in mechanical strength. As a method for dispersing a filler into a polyvinyl chloride resin compound without having to mix the filler for a long time using a mixer, Japanese Patent Application Laid-Open No. 80412/1983 discloses a method in which the filler is added before or during polymerization. However, according to the study results of the present inventors, even if a powdered inorganic filler that is "insoluble in water and monomers" is directly added to the reaction vessel and polymerized, it will be dispersed inside the polyvinyl chloride resin product. The amount of powdered inorganic filler applied is small, and most of the powdered inorganic filler is merely attached to the surface of the polyvinyl chloride resin particles. Although molding a compound using such a polyvinyl chloride resin has the effect of reinforcing the function of the filler to some extent, it cannot be said to be sufficient. The present inventors conducted intensive research on a method for substantially completely retaining a powdered inorganic filler inside polyvinyl chloride resin particles. A soluble initiator is used to produce a powder that is insoluble in at least one type of water and the monomer, using a vinyl chloride monomer or a vinyl chloride monomer as a main ingredient in combination with other vinyl monomers that can be copolymerized with the vinyl chloride monomer. Polyvinyl chloride resins are made by pre-treating powdered inorganic fillers with a silane coupling agent and directly adding them to the reaction vessel before or during polymerization to carry out suspension polymerization. It was discovered that the particles were dispersed inside the particles and strongly bonded to the polyvinyl chloride resin. Furthermore, surprisingly, when inorganic micro hollow spheres are used as a filler, the destruction rate of the micro hollow spheres during molding is small, perhaps because the micro hollow spheres are reinforced with a shell of polyvinyl chloride resin, resulting in a lower yield. It was discovered that the weight of the polyvinyl chloride resin molded article can be further reduced, and the present invention was achieved. By polymerizing polyvinyl chloride monomer etc. according to the method of the present invention, powdery inorganic minute hollow spheres are almost completely dispersed in the product polyvinyl chloride resin particles, and the polyvinyl chloride resin To obtain a polyvinyl chloride resin composition whose specific gravity is adjusted without reducing the strength of a molded article. The amount of at least one type of water- and monomer-insoluble powdery inorganic micro hollow spheres added directly to the reaction vessel before or during polymerization is 0.001 to 500 parts by weight, preferably 0.001 to 500 parts by weight, based on 100 parts by weight of monomers. 0.01〜
A suitable amount is 250 parts by weight, more preferably 0.1 to 100 parts by weight. If the amount added is less than 0.001 parts by weight, no reinforcing effect by the powdered inorganic micro hollow spheres will be observed, and if the amount added exceeds 500 parts by weight, it will be difficult to completely disperse it inside the product polyvinyl chloride resin particles. The required amount of silane coupling agent to treat powdered inorganic micro hollow spheres is as a rough guide: Silane coupling agent (g) = Amount of inorganic micro hollow spheres used (g) x Specific surface area of inorganic micro hollow spheres (m ² /g)/Specific wetted area of silane coupling agent (m ² /g) It is calculated by the formula, but it is 0.001 to 1000 parts by weight, preferably 0.01 to 1000 parts by weight, per 100 parts by weight of powdered inorganic microscopic hollow spheres. A suitable amount is 100 parts by weight, more preferably 0.1 to 10 parts by weight. If the amount is less than 0.001 part by weight, it is difficult to sufficiently treat the surface of the powdered inorganic microscopic hollow spheres. If the amount exceeds 1000 parts by weight, the treatment effect will decrease. Examples of the inorganic microscopic hollow spheres include microscopic hollow spheres made of alumina, silica, zirconia, magnesia, composites thereof, glass, shirasu, fly ash, carbon, sodium silicate, and polymers of borates and phosphates. . Silane coupling agents for treating powdered inorganic microhollow spheres generally include at least one hydrolyzable group on the silicon atom and at least one functional group reactive with or having an affinity for vinyl chloride monomers or polymers. It can be said to be a compound having a group containing 0 to 2 inert groups, or a compound in which a plurality of such silicon derivatives are connected. The hydrolyzable groups include chlorine, alkoxy groups, primary amino groups, acyloxy groups, etc., and functional groups that are reactive or have affinity with vinyl chloride monomers or polymers include primary amino groups, secondary amino groups, etc. These include amino groups, epoxy groups, vinyl groups, mercapto groups, chlorine, methacryloxy groups, peroxy groups (including in peresters and dicarbonates), and the like. Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyl. Triethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane , γ-methacryloxypropyltrimethoxysilane, acryltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, bis[3-(triethoxysilyl)propyl]amine, bis[3-( methoxysilyl)propyl]ethylenediamine, 2-chloroethyltriethoxysilane, chloromethyltriethoxysilane, chlorophenyltriethoxysilane, 1-(dimethylchlorosilyl)-2(p,m-
chloromethylphenyl)ethane, mercaptoethyltriethoxysilane, mectacryloxyethyldimethyl (3-trimethoxysilylpropyl)
Ammonium chloride, methyl-3-[2-(3
-trimethoxysilylpropylamino)ethylamino]3-propionate, 3-(N-styrylmethyl-2-aminoethylamino)-propyltrimethoxysilane hydrochloride, 1-trichlorosilyl-2-(p,m-chloromethyl phenyl)ethane, triethoxysilylpropylethyl carbamate, N-(triethoxysilylpropyl)urea, 1-trimethoxysilyl-2-1(p,m-
aminomethyl) phenylethane, 1-trimethoxysilyl-2-(p,m-chloromethyl) phenylethane, trimethoxysilylpropylallylamine, trimethoxysilylpropyldiethylenetriamine, vinyltris(t-butylperoxy)silane, P-aminophenyl trimethoxysilane, 2-styrylethyltrimethoxysilane,
Aminoethylaminomethylphenethyltrimethoxysilane and the like can be mentioned. In the present invention, as a method for pre-treating inorganic microscopic hollow spheres with a silane coupling agent, (1) while forcibly stirring the microscopic hollow spheres with a V-blender etc., an aqueous solution of a silane coupling agent is sprayed with dry air or N ₂ gas. Method. (2) A method in which microscopic hollow spheres are dispersed in water, a silane coupling agent aqueous solution is added to the slurry, and after stirring, the slurry is allowed to stand, allowing the microscopic hollow spheres to settle and separate, and then dry. and other methods. In the present invention, a PH regulator, a chain transfer agent, a polymerization inhibitor, etc. can be used as necessary. Further, even if a trace amount of an inorganic substance is added to the reaction vessel to the extent that the effects of the present invention are not prevented, this does not deviate from the scope of the present invention. The present invention is mainly applied to the polymerization of vinyl chloride monomers, but it is also applicable to copolymerization with vinyl monomers that can be copolymerized with vinyl chloride monomers containing 50% or more of vinyl chloride monomers. be able to. Vinyl monomers that can be copolymerized with vinyl chloride monomers include:
Alkyl vinyl esters such as vinyl acetate, alkyl vinyl ethers such as cetyl vinyl ether, α-monoolefinic monomers such as ethylene or propylene, acrylic acid alkyl esters such as methyl acrylate, or methyl methacrylate. Examples include methacrylic acid alkyl esters. Furthermore, it can also be applied to graft polymerization of vinyl chloride monomer onto ethylene-vinyl acetate copolymer or ethylene-propylene copolymer. In the suspension polymerization in the present invention, suspending agents used in suspension polymerization, such as ordinary vinyl chloride monomers, can be used. As a suspending agent, one or two types of synthetic polymer substances such as polyvinyl alcohol (including partially saponified polyvinyl acetate), cellulose derivatives such as methylcellulose, polyvinylpyrrolidone, maleic anhydride-vinyl acetate copolymer, etc. Mixtures of the above may be used. Initiators include lauroyl peroxide, benzoyl peroxide, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate, di-3,5,5-trimethylhexanoyl peroxide, bis(4-tert-butylcyclohexyl) peroxide. Oxydicarbonate, di3-
Methoxybutyl peroxydicarbonate, di3
-organic peroxides such as methoxy-3-methylbutyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, acetylcyclohexylsulfonyl peroxide and α,
α'-azobisisobutyronitrile, α,α'-azobis-2,4-dimethylvaleronitrile, α,
One type or a mixture of two or more types of azo compounds such as α'-azobis-4-methoxy-2,4-dimethylvaleronitrile can be used. The initiator may be added to the water charged before the polymerization operation, or may be added at any other time. The initiator may be added after heating to a predetermined polymerization reaction temperature, or one or more initiators may be divided and added at various times. The effects of the present invention are not impaired even if known additives used together with suspending agents are added to the reaction vessel. The method of the present invention is carried out under stirring at a polymerization reaction temperature of 35 to 80°C.
Preferably, the temperature is within the range of °C. Examples of the present invention will be shown next, but these are not intended to limit the scope of the present invention. Mechanical strength tests (tensile tests) and specific gravity measurements were carried out using vinyl chloride polymers in the following manner. Vinyl chloride polymer, inorganic micro hollow spheres (parts by weight listed in Table 2), 100 parts by weight of DOP, organic tin laurate stabilizer (Nitto Kasei, TVS)
#TL-800) 2 parts by weight, organotin sulfur-containing stabilizer (Nitto Kasei, TVS #1350) 1 part by weight,
5 parts by weight of PMMA reinforcing agent, 2 parts by weight of carbon black
The specific gravity of a sheet with a thickness of 2 mm obtained by blending parts by weight, kneading and molding at 150°C for 10 minutes, and Shimadzu Autograph IS2000 (JIS6745, tensile speed 10
Perform a tensile test (mm/min) to determine strength and elongation. The results are shown in Table 2. Example 1, Comparative Example 1, Comparative Example 3 Into a stainless steel polymerization reaction vessel with an internal volume of 200 kg, 100 kg of pure water, partially saponified polyvinyl acetate, α,α'-azobis-2,4- in the amounts listed in Table 1 were added. Dimethylvaleronitrile (ADN), inorganic microscopic hollow spheres (Nippon Fillite Co., Ltd., Fillite 200/7), γ-methacryloxypropyltrimethoxysilane, γ
- Micro hollow spheres (Filite 200/7) treated with methacryloxypropyltrimethoxysilane and vinyl chloride monomer were charged, the temperature was raised to a polymerization reaction temperature of 57℃ with stirring, and after polymerization for 8 hours, unreacted monomers were removed. The body was drained and the polymer was taken out. Table 1 shows the amount of micro hollow spheres (Filite 200/7) dispersed inside the product polyvinyl chloride particles and attached to the surface. Comparative Example 2 Polymerization was carried out under the same conditions as in Example 1, except that inorganic micro hollow spheres (Filite 200/7) and γ-methacryloxypropyltrimethoxysilane were not used. The results are shown in Table 1. (Note) Method for treating phyllite 200/7 (B) with γ-methacryloxypropylmethoxysilane (A): Mix 15 kg of B with 50 kg of pure water, and adjust the pH to 4 using glacial acetic acid.
After adjusting the temperature, add 0.6 kg of A and heat to 80℃. After cooling, it was dehydrated and dried and used in Example 1.

【table】

[Table] Tables 1 and 2 show that by charging inorganic minute hollow spheres treated with a silane coupling agent into a reaction vessel and carrying out suspension polymerization of vinyl chloride monomer, the tensile strength (Kg It is clear that it is possible to obtain molded articles with a large diameter (/cm ² ). Furthermore, even if inorganic micro hollow spheres (Comparative Example 1) or a silane coupling agent and inorganic micro hollow spheres (Comparative Example 3) were charged into a reaction vessel and suspension polymerization of vinyl chloride monomer was carried out, It is clear that the properties of the molded article are far inferior to those of No. 1.

Claims (1)

[Claims] 1 In an aqueous medium, using a monomer-soluble initiator, vinyl chloride monomer or vinyl chloride monomer as a main component, and in combination with other vinyl monomers that can be copolymerized therewith, at least one Polymerization is characterized in that powdered inorganic micro hollow spheres insoluble in water and monomers of various types are treated with a silane coupling agent in advance and added directly to a reactor before or during polymerization to perform suspension polymerization. A method for producing a vinyl chloride composition.