JPH0414682B2 - - Google Patents

Description

[Detailed description of the invention]

In the present invention, a powder filler is directly added to a reaction vessel before or during polymerization, and the specific gravity of the vinyl chloride polymer molded article is adjusted so that the mechanical strength and surface smoothness of the molded article are not deteriorated. The present invention relates to a method for producing a vinyl polymer 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 vinyl chloride resin, increasing the amount (reducing cost), adjusting specific gravity,
Various fillers are used for purposes such as coloring, imparting electrical conductivity, and reinforcing effects. Examples of weight increasing and specific gravity adjusting agents include silica, clay, talc, calcium carbonate, titanium oxide, alumina, and minute hollow spheres thereof; coloring agents include carbon black, calcium carbonate, titanium oxide, etc.; Carbon black is used to provide antistatic properties; glass fiber, talc, etc. are used to stop elongation and increase the reinforcing effect; foaming agents include azodicarbonamide, dinitron pentamethylenetetramine, etc. are used respectively. These methods of use generally involve mixing the vinyl 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 molded product is not only discolored but also heavily colored, resulting in a molded product with poor commercial value. 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. On the other hand, if mixing in the mixer is not sufficient, not only will the intended function of the filler not be achieved, but it will also cause roughening of the surface of the molded product and reduction in mechanical strength. Therefore, a method has been devised in which the filler is dispersed in a vinyl chloride resin compound without having to mix it in a mixer for a long time. A method is disclosed. However, according to the study results of the present inventors, even if a powdery inorganic filler that is "insoluble in water and monomers" is directly added to the reaction vessel and polymerized, the inside of the particles of the vinyl chloride resin product The amount of powdered inorganic filler dispersed in the
Most of the powdered inorganic filler is simply attached to the surface of the vinyl chloride resin particles. Even if a compound using such a vinyl chloride resin is molded, it is effective to exert the function of a filler to some extent, but it cannot be said to be sufficient. Therefore, in order to retain the powder filler almost completely inside the vinyl chloride resin particles,
When polymerizing vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride monomer using a monomer-soluble initiator in the presence of a suspending agent in an aqueous medium, at least one type of water and a monomer are used. It has been proposed to carry out polymerization by surface-treating a powdery filler insoluble in water with a silane coupling agent and directly adding it to the polymerization system before or during polymerization (Japanese Patent Laid-Open No. 192412-1982).
issue). When using inorganic micro hollow spheres whose surface has been treated with a silane coupling agent as a filler,
The surface of the micro hollow sphere and the vinyl chloride resin are strongly bonded, and the surface is reinforced by creating an outer shell of the vinyl chloride resin, and the micro hollow sphere is less likely to break during molding. mosquito,
The resulting vinyl chloride resin can be made lighter and has improved mechanical properties (tensile strength, Kg/mm ² ). However, when this filler is blended with vinyl chloride resin, there is a drawback that the surface of the molded product becomes uneven. As a result of intensive research to improve this drawback, the inventors of the present invention found that, together with inorganic micro hollow spheres whose surface was treated with a silane coupling agent, a small amount of a blowing agent whose surface was treated with a nonionic surfactant with an HLB of 10 or less was used at the same time. The present invention was achieved by discovering that when used, the surface unevenness of the molded product is eliminated and the surface smoothness is significantly improved without deteriorating the mechanical properties (tensile strength [Kg/mm ² ]). did. When a vinyl chloride monomer is polymerized according to the method of the present invention, a vinyl chloride resin polymer composition in which inorganic micro hollow spheres are almost completely dispersed and held in the resulting polymer particles. The vinyl chloride resin molded product obtained therefrom has a specific gravity adjusted as desired without a decrease in mechanical properties (tensile strength, Kg/mm ² ), and a smooth surface. The amount of at least one type of water- and monomer-insoluble inorganic micro hollow spheres added directly to the reaction vessel before or during polymerization is 0.001 to 500 parts by weight, preferably 0.01 to 500 parts by weight, based on 100 parts by weight of monomers. 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 on the mechanical properties of the resin molded product will be observed, and if the amount added exceeds 500 parts by weight, it will be difficult to completely disperse it inside the resulting vinyl chloride polymer particles. . As a rough guide, the required amount of silane coupling agent for surface treatment of inorganic micro hollow spheres is as follows: 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).
A suitable range is 0.001 to 1000 parts by weight, preferably 0.01 to 100 parts by weight, and more preferably 0.1 to 10 parts by weight per 100 parts by weight. If the amount is less than 0.001 part by weight, it is difficult to sufficiently treat the surface of the inorganic micro hollow spheres. If the amount exceeds 1000 parts by weight, the surface treatment effect will decrease. Add to the reaction vessel at the same time as inorganic microscopic hollow spheres whose surface has been treated with a silane coupling agent.
The amount of organic blowing agent used is 0.001 to 100 parts by weight of the monomer charged in organic blowing agents whose surface has been treated with a nonionic surfactant with an HLB of 10 or less.
A suitable range is 2 parts by weight, preferably 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.2 parts by weight. If the amount used is less than 0.001 parts by weight, the effect of smoothing the surface by eliminating unevenness on the surface of the molded product is insufficient, and if the amount used exceeds 2 parts by weight, the mechanical properties (tensile strength [Kg/ mm ² ]). The amount of nonionic surfactant used to treat organic blowing agents is 0.1 parts by weight per 100 parts by weight of organic blowing agents.
A suitable range is from 10,000 parts by weight, preferably from 1 to 1,000 parts by weight, and more preferably from 10 to 500 parts by weight. If the amount is less than 0.1 parts by weight, it is difficult to completely disperse and retain the organic blowing agent inside the product vinyl chloride resin particles, and even if the amount exceeds 10,000 parts by weight, the dispersion and retention effect will not change. The inorganic micro hollow spheres include alumina, silica, zirconia, magnesia, composites thereof, glass, shirasu, fly ash,
Examples include micro hollow spheres made of carbon, sodium silicate, calcium silicate, borate or phosphate polymers, or mixtures thereof. Silane coupling agents for treating inorganic microhollow spheres generally have 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 compounds are connected. The hydrolyzable groups include chlorine, alkoxy groups, primary amino groups, acyloxy groups, etc., and the 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-aminopropylsilane. rutriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane , γ-methacryloxypropyltrimethoxysilane, allyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, bis[3-(triethoxysilyl)
propyl]amine, bis[3-(trimethoxysilyl)propyl]ethylenediamine, 2-chloroethyltriethoxysilane, chloromethyltriethoxysilane, chlorophenyltriethoxysilane, 1-(dimethylchlorosilyl)-2(p, m −
chloromethylphenyl)ethane, mercaptoethyltriethoxysilane, methacryloxyethyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, methyl-3-[2-(3-
Trimethoxysilylpropylamino)ethylamino]-3-propionate, 3-(N-styrylmethyl-2-aminoethylamino)-propyltrimethoxysilane hydrochloride, 1-trichlorosilyl-
2-(p,m-chloromethylphenyl)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)
Examples include silane, P-aminophenyltrimethoxysilane, 2-styrylethyltrimethoxysilane, and aminoethylaminomethylphenethyltrimethoxysilane. In the present invention, as a method for surface treating inorganic microscopic hollow spheres with a silane coupling agent, (1) While forcibly stirring the filler using a V-blender, etc., the aqueous solution of the silane coupling agent is mixed with dry air or
Method of atomizing with _N2 gas. (2) A method in which inorganic micro hollow spheres are dispersed in water, a silane coupling agent aqueous solution is added to the slurry, and after stirring, the mixture is allowed to stand, and the hollow spheres are separated by sedimentation and dried. and other methods. Examples of the above-mentioned organic blowing agents include 2,2'-azoisobutyronitrile, azohexahydrobenzonitrile, azodicarbonamide, diazoaminobenzene, benzene sulfohydrazide, benzene-1,3-disulfohydrazide, and diphthalamic acid. enylsulfone-3,3'-disulfohydrazide, diphenyloxide-4,4'-disulfohydrazide, N,
N'-dinitropentamethylenetetramine, N,
Examples include N'-dinitroso-N,N'-dimethylterephthalamide, terephthalazide and other organic decomposable blowing agents. Examples of nonionic surfactants for surface treatment of organic blowing agents include polyoxyethylene cetyl ether, polyoxyethylene lauryl ether,
Polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene oxylphenyl ether, polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyethylene glycol dilaurate, polyethylene glycol distear rate, polyethylene glycol oleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, polyoxyethylene nonyl phenyl stearate,
You can choose from polypropylene glycol dilaurate and others with HLB 1.0 to 10.0. In the present invention, the organic blowing agent is HLB1.0~
As a method for surface treatment with a nonionic surfactant of 10.0, it is sufficient to thoroughly mix the foaming agent and the surfactant or an alcoholic solution of the surfactant. In the present invention, a PH regulator, a chain transfer agent, a polymerization inhibitor, etc. can be used as necessary. Furthermore, it does not depart from the scope of the present invention even if a trace amount of an inorganic substance is added to the reaction vessel to the extent that it does not impede the effects 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 more synthetic polymer substances such as polyvinyl alcohol (including partially saponified polyvinyl acetate), cellulose derivatives such as methylcellulose, polyvinylpyrrolidone, and maleic anhydride-vinyl acetate copolymer are used. Mixtures can be used. Examples of initiators include lauroyl peroxide, benzoyl peroxide, tert-butyl peroxypiparate, diisopropyl peroxydicarbonate, di-3,5,5-trimethylhexanoyl peroxide, bis(4-tert-butylcyclohexyl) peroxide. Oxydicarbonate, di3-
Methoxybutyl peroxycarbonate, di3-
Organic peroxides and α, α′-
azobis-2,4-dimethylvaleronitrile,
One or a mixture of two or more azo compounds such as α,α'-azobis-4-methoxy-2,4-dimethylvaleronitrile and α,α'-azobisisobutyronitrile 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 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. Notes regarding the Examples and Comparative Examples are as follows. (1) Mechanical property measurement tests (tensile tests) and specific gravity measurements were carried out using vinyl chloride weights in the following manner. Vinyl chloride polymer, inorganic microscopic hollow spheres (parts by weight listed in Table 2),
100 parts by weight of DOP, 2 parts by weight of organotin laurate stabilizer (Nitto Kasei, TVS#TL-800), 2 parts by weight of organotin-containing sulfur stabilizer (Nitto Kasei, TVS
#1350) 1 part by weight, 5 parts by weight of PMMA reinforcing agent and 2 parts by weight of carbon black were mixed and heated at 150°C.
2mm thick after kneading and molding for 10 minutes.
Using the sheet, measure the specific gravity (JISZ8807) and perform a tensile test using Shimadzu Autograph JS2000 (JIS K6723, tensile speed 200mm/min) to measure strength and elongation. (2) The smoothness of the surface of the molded product is indicated by the following symbol. ◎: Smooth and smooth. ○: Smooth, but with small unevenness partially. △: There are many unevenness. ×: There are large irregularities on the entire surface. (3) Description of raw materials Filite 200/7: A trademark of Nippon Filite Co., Ltd.'s product. Microscopic hollow spheres whose main components are SiO ₂ and Al ₂ O ₃ . Particle size distribution 5-300μ. Average specific gravity 0.7 Example 1 In a stainless steel polymerization reaction vessel with an internal volume of 200 kg, 100 kg of pure water, partially saponified polyvinyl acetate and α,α′-azobis-2,4-dimethylvaleronitrile ( ADN), micro hollow spheres (Filite 200/7) surface treated with γ-methacryloxypropyltrimethoxysilane, azodicarbonamide (particle size 5μ) and vinyl chloride surface treated with polyoxyethylene lauryl ether (HLB3.8) Charge the monomers and adjust the polymerization reaction temperature while stirring.
After raising the temperature to 57°C and polymerizing for 8 hours, unreacted monomers were discharged and the polymer product was taken out and dried. Table 1 shows the amount of phyllite 200/7 dispersed and retained inside the particles of the polymer product or attached to the particle surface. Table 2 shows the properties of the molded products. Regarding the treatment of phyllite 200/7 (B) with γ-methacryloxypropylmethoxysilane (A), mix 15 kg of B with 50 kg of pure water and treat with glacial acetic acid.
After adjusting the pH to 4, add 0.6 kg of A and heat to 80℃.
After cooling, it was dehydrated and dried. Also, polyoxyethylene lauryl ether (C)
Regarding the treatment method of azodicarbonamide (D), 0.05 kg of C and 0.05 kg of D were mixed well. Comparative Example 1 In the method of Example 1, polyoxyethylene lauryl ether (HLB12.5) was used instead of the polyoxyethylene lauryl ether (HLB3.8).
A polymer product was produced in the same manner as in Example 1, except that . The results are shown in Tables 1 and 2. Comparative Examples 2 to 6 100 kg of pure water was placed in a stainless steel polymerization reaction vessel with an internal volume of 200 mm, and partially saponified polyvinyl acetate α,α'-azobis-2,4-dimethylvaleronitric (ADN) was added in the amounts listed in Table 1. ), γ in the same manner as in Example 1
- Filite 200/7 surface treated with methacryloxypropyltrimethoxysilane or untreated Filite 200/7, azodicarbonamide surface treated with polyoxyethylene laur ether (HLB3.8) or azo without surface treatment Dicarbonamide and vinyl chloride monomer were charged, and the polymerization reaction temperature was raised to 57°C while stirring.
After polymerization for a period of time, unreacted monomers were discharged, and the polymer product was taken out and dried. Table 1 shows the amount of phyllite 200/7 retained dispersed within the particles of the polymer product or attached to the particle surface. Table 2 shows the properties of the molded articles. Comparative Example 7 In Example 1, polymerization was carried out under the same conditions as in Example 1, except that filite 200/7, γ-methacryloxypropyltrimethoxysilane, polyoxyethylene lauryl ether, and azodicarbonamide were not used. . The results are shown in Tables 1 and 2.

【table】

[Table] As shown in Table 2, micro hollow spheres (Filite 200/7) whose surface was treated with a silane coupling agent (γ-methacryloxypropyltrimethoxysilane) and a surface treated with polyoxyethylene lauryl ether of HLB 3.8. By using treated azodicarbonamide at the same time, it is possible to reduce the weight of vinyl chloride resin molded products without reducing their mechanical properties (tensile strength), and it is also possible to smooth the surface of the molded products. I understand that.

Claims (1)

[Claims] 1. A vinyl chloride monomer or a mixture of vinyl chloride monomers and other vinyl monomers that can be copolymerized therewith in an aqueous medium using a monomer-soluble initiator. When carrying out suspension polymerization in a polymerization reaction vessel, at least one type of water- and monomer-insoluble inorganic micro hollow spheres treated with a silane coupling agent and a nonionic surface activity with an HLB of 10 or less are used. 1. A method for producing a vinyl chloride resin composition, characterized in that the polymerization is carried out by directly adding an organic blowing agent treated with an organic blowing agent to the polymerization reaction vessel before or during the polymerization. 2. In the method according to item 1, the inorganic micro hollow spheres have a specific gravity of 0.15 to 0.80 and a particle size of 5 to 300μ.
The method characterized in that