JPS6362521B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to suspension polymerization of vinyl chloride. [Prior art] When producing vinyl chloride resin industrially, a suspension polymerization method is used in which vinyl chloride monomers are dispersed in an aqueous medium in the presence of a suspension stabilizer and polymerized using an oil-soluble initiator. is widely practiced. The vinyl chloride polymer produced by such a method is a powder with an average particle size of 100 to 150μ and a particle size distribution number of 10 to 200μ. This polymer powder contains heat stabilizers, lubricants, plasticizers,
A molded product is made by adding appropriate amounts of colorants, fillers, etc. Products mixed with plasticizers are called soft products, and products with no or very small amount of plasticizer added are called hard products, and each is in great demand for agricultural vinyl, electric wire coverings, hard pipes, etc. Particularly recently, there has been a demand for vinyl chloride polymer powders with a sharp particle size distribution and a large average particle size (for example, an average particle size of 150 to 2000 μm). For example, it can be blended with plastisol of vinyl chloride resin for paste to make the surface of vinyl chloride resin molded products matte and non-slip, and used when molding gloves using a method such as dip molding. Therefore, there is a demand for a vinyl chloride polymer powder obtained by a suspension polymerization method that has a sharp particle size distribution and a large average particle size. As a method of imparting effects such as matteness and anti-slip properties to dip molded products, there has been a method of blending vinyl chloride polymer powder (average particle size 100 to 150μ) obtained by a normal suspension polymerization method with talc, clay, etc. There are methods such as blending inorganic powders, such as methods, and creating grain in the graining process. However, when this method is adopted, the particle size distribution of the vinyl chloride polymer powder obtained by ordinary suspension polymerization is broad, the average particle size is small, and the absorbency of plasticizer is large, resulting in matte and non-slip properties. The effect is small. When this method is adopted, although a matting effect can be obtained to some extent by using an inorganic filler such as talc or clay, the mechanical strength of the molded product is significantly reduced. If this method is adopted, a texturing process is required, which reduces productivity and increases costs. [Problems to be Solved by the Invention] The purpose of the present invention is to provide a method for producing a vinyl chloride polymer powder with a sharp particle size distribution, a large average particle size, and a significantly low plasticizer absorption property by improving the above method. It is to provide. [Means for Solving the Problems] The present invention provides a method for treating vinyl chloride monomer or vinyl chloride monomer as a main component in an aqueous medium in the presence of a suspension stabilizer using a monomer-soluble initiator. When polymerizing a mixture of this and other vinyl monomers that can be copolymerized (hereinafter referred to as vinyl chloride monomer, etc.),
The gist is that the polymerization is carried out in the presence of at least one kind of water- and monomer-insoluble organic powdery polymer surface-treated with a nonionic surfactant in the polymerization system. By this method, it is possible to obtain a vinyl chloride polymer powder having a sharp particle size distribution, a large average particle size, and extremely low plasticizer absorption. The amount of at least one kind of organic powdery polymer insoluble in water and vinyl chloride monomer, etc. to be present in the polymerization system is 1 part by weight per 100 parts by weight of the monomers charged.
~1000 polymerization parts are suitable. Less than 1 part by weight and
If the amount added is 1000 parts by weight or more, it is difficult to obtain vinyl chloride polymer powder with a desired particle size (150 to 2000 μm). The amount of nonionic surfactant used to surface treat organic powder polymers is 100% of the monomer used.
A suitable amount is 0.01 to 20 parts by weight.
If the amount is less than 0.01 part by weight, it is difficult to obtain a vinyl chloride polymer powder of a desired size. Even if 20 parts by weight or more of nonionic surfactant is used, the effect remains the same. The surface treatment of an organic powdery polymer with a nonionic surfactant includes spraying the powdery polymer with a nonionic surfactant dissolved in an appropriate solvent, or polymerizing it in a reaction vessel. This can be carried out by stirring and mixing an organic powdery polymer dispersed in water and a nonionic surfactant before starting. The at least one type of organic powder polymer includes vinyl chloride polymer, styrene polymer,
You can choose from ethylene polymer, propylene polymer, polyamide, polyester, acrylic resin, polycarbonate, vinylidene chloride polymer, melamine resin, phenol resin, epoxy resin, diallyl phthalate resin, urethane resin, acetal resin, etc. Vinyl chloride polymer powder obtained by suspension polymerization is best. As the vinyl chloride polymer powder, we can use not only vinyl chloride homopolymer but also copolymer powder of vinyl chloride monomer and comonomers such as vinyl acetate, cetyl vinyl ether, methyl acrylate, and methyl methacrylate that can be copolymerized with vinyl chloride monomer. can be used.
Furthermore, the vinyl chloride polymer powder obtained by the method of the present invention can also be used. The organic powder polymer preferably has an average particle diameter of 30 to 2000 μm and a bulk specific gravity of 0.1 to 1.0. Although particles with an average particle size of 2000 μm are not normally available, they can be obtained by repeating the polymerization of the present invention. The amount of the organic powder polymer to be added is preferably 1 to 99% by weight based on the total amount of the vinyl chloride monomer, etc. and the organic powder polymer. It is preferably 1 to 50% by weight, more preferably 1 to 50% by weight. Examples of nonionic surfactants for surface treating organic powdery polymers include polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, and polyoxyethylene nonyl ether. enyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyethylene glycol dilaurate, polyethylene glycol distearate, polyethylene glycol oleate, sorbitan monopalmitate, sorbitan monostearate, Examples include sorbitan monooleate, polyoxyethylene nonyl phenyl stearate, and polypropylene glycol dilaurate. This nonionic surfactant preferably has a KLB of 1.0 to 10.0. More preferably, it is 2.0 to 8.0. If KLB is smaller than 1.0 or larger than 10.0, it is difficult to obtain a polymer with a large particle size even if polymerization is carried out according to the present invention. In the present invention, a PH regulator, a chain transfer agent, a polymerization inhibitor, etc. can be used as necessary. Further, it is not outside 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 invention. In the suspension polymerization in the present invention, suspending agents used in suspension polymerization, such as ordinary vinyl chloride monomers, can be used. As the suspending agent, one type or a mixture of two or more types of synthetic polymeric substances such as cellulose derivatives such as partially saponified polyvinyl methylcellulose acetate, polyvinylpyrrolidone, and maleic anhydride-vinyl acetate copolymer can be used. The amount of this suspending agent used is based on the monomer charged.
100~10000ppm is good, preferably 300~
It is 3000ppm. Examples of 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 peroxycarbonate, di3-
Organic materials such as methoxy 3-methylbutyl peroxydicarbonate, di-secondary butyl peroxydicarbonate, di1-methylheptyl peroxydicarbonate, di2-ethylhexyl peroxydicarbonate, acetylcyclohexylsulfonyl peroxide, isobutyryl peroxide, etc. Peroxides and α,α′-azobisisobutyronitrile, α,α′-azobis-2,4-dimethylvaleronitrile, α,α′-azobis-4-methoxy-2,4-dimethylvaleronitrile, etc. One type or a mixture of two or more types of azo compounds can be used. The polymerization of the present invention is preferably carried out under stirring at a polymerization temperature in the range of 25 to 80°C. [Effects of the Invention] According to the present invention, it is possible to produce a vinyl chloride polymer powder that has a sharp particle size distribution, a large average particle diameter, and extremely low plasticizer absorption. [Examples] Next, Examples of the present invention will be shown, but none of these should limit the scope of the present invention. (1) The plasticizer absorption rate of the product, vinyl chloride resin, is determined by adding 100 parts by weight of resin and 50 parts by weight of DOP to a planetary mixer (80°C) connected to a Brabender Plastograph, and achieving equilibrium during stirring and mixing. Expressed in time (minutes) indicating torque. The smaller this time, the faster the absorption rate. (2) Mechanical property measurement test (tensile test), matting effect, and anti-slip effect were conducted using the following methods.
To 100 parts by weight of P1000 paste resin, add the amount of vinyl chloride resin or talc shown in the Examples and Comparative Examples, and add 50 parts by weight of DOP, 2 parts by weight of organotin laurate stabilizer, and 1 weight of organotin sulfur-containing stabilizer. 2 parts by weight of carbon black, poured into a stainless steel tray with a depth of 2 m/m, heated at 200℃ for 5 minutes, and a sheet with a thickness of 2 m/m obtained by Shimadzu Autograph
The tensile strength] (Kg/mm ² ) was measured using IS2000 (JIS K6723, tensile speed 200 mm/min). The matte effect and anti-slip effect are determined by visual observation and texture of the 2 m/m sheet. [Matte effect] No gloss on the surface...◎ 〃 Slightly...○ Slight gloss on the surface...△ 〃 Much...× [Non-slip effect] Not slippery...◎ Slightly slippery...○ Slightly slippery...△ Slippery ... × (3) The viscosity of plastisol is the viscosity of a sol-like compound obtained by mixing the polymer product obtained in the example or comparative example and talc with DOP and a stabilizer in a paste resin at the ratio shown in Table 2. Synchronous electric rotary viscometer (Bismetron model)
It is measured in VA-1 (Tokyo Metrology) and expressed in centipoise (cps). Comparative Example 1 In a stainless steel autoclave with an internal volume of 200 kg, 100 kg of pure water and POVAL (partially saponified polyvinyl acetate; degree of saponification 70.0%, 4%/H ₂ O - viscosity at 20°C)
6.0cps) and 15g of diisopropyl peroxydicarbonate (IPP), and after deoxidizing,
After 50 kg of vinyl chloride monomer was charged and the temperature was raised to 45° C. with stirring for 9 hours of reaction, unreacted monomer was discharged and the polymer product was taken out and dried. Table 1 shows the average particle diameter, particle size distribution, plasticizer absorption rate, etc. of the polymer product. Examples 1 to 7, Comparative Example 2 In a stainless steel autoclave with an internal volume of 200, 100 kg of pure water and the amount of poval (partially saponified polyvinyl acetate; saponification degree 70.0%, 4%/
H ₂ O - 20℃ viscosity 6.0 cps), diisopropyl peroxydicarbonate, nonionic surfactant (polyoxyethylene lauryl ether, HLB3.8)
After charging the polymer product obtained in Comparative Example 1 and deoxidizing it, vinyl chloride monomer was charged and the temperature was raised to 45°C with stirring, and the reaction was carried out for 9 hours, after which unreacted monomer was discharged. The polymer product was removed and dried. Table 1 shows the average particle diameter, particle size distribution, plasticizer absorption rate, etc. of the polymer product. Examples 8 to 12 In the method of Examples 1 to 7, Example 2, Example 8 or powdered melamine resin, powdered epoxy resin, powdered phenolic resin was used instead of the polymer product obtained in Comparative Example 1. Example 1~
Polymerization was carried out in the same manner as in method 7, and a polymer product was obtained. The average particle size of the polymer product is shown in Table 2. Examples 13 to 15, Comparative Examples 3 to 10 The polymer product or talc of Example 2, Comparative Example 1 or Comparative Example 2 was mixed with DOP, stabilizers ((A),
Table 3 shows the viscosity of the plastisol compound and the properties of the molded product (tensile strength, matte surface, anti-slip effect) when blended with paste resin (B)), carbon black, etc. From the results in Table 1, we found that powdered vinyl chloride resin was charged into a polymerization vessel together with a nonionic surfactant, and
It is clear that by polymerizing vinyl chloride monomers, it is possible to obtain vinyl chloride resin products with a large average particle size and low plasticizer absorption. From the results in Table 2, it is clear that even if a powdered organic polymer other than vinyl chloride resin powder is used, a vinyl chloride resin having a large average particle size can be obtained. From the results in Table 3, the vinyl chloride polymer obtained by the method of the present invention has a good matte surface and anti-slip effect, and the vinyl chloride polymer obtained by the method of the present invention has a large average particle diameter. It is clear that the plastisol compound using this method has no viscosity change and molded products with excellent properties can be obtained. Note that the change in the viscosity of the plastisol compound makes the molding conditions of the industrial molding process extremely difficult.

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[Table] Stabilizer (B): Organotin sulfur-containing stabilizer

Claims (1)

[Scope of Claims] 1. In an aqueous medium, using a monomer-soluble initiator, vinyl chloride monomer or vinyl chloride monomer and other vinyl monomers mainly composed of vinyl chloride monomer and copolymerizable with the vinyl chloride monomer are produced. When polymerizing the mixture with
Vinyl chloride, characterized in that the polymerization is carried out in the presence of an organic powdery polymer insoluble in water and monomers of various types and surface-treated with a nonionic surfactant in the polymerization system. Method for producing a polymer. 2 In the method described in item 1, the organic powdery polymer has an average particle diameter of 30 to 2000μ and a bulk specific gravity of 0.1 to 1.0.
The above method, characterized in that the vinyl chloride resin is a polyvinyl chloride resin. 3. The method according to item 1 or 2, wherein the nonionic surfactant has an HLB of 1.0 to 10.0.