JPH0570663B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin composition comprising polyvinyl chloride and a polymer plasticizer and having good processability. Vinyl chloride resin has excellent physical and mechanical properties, so it has many uses such as hard, semi-hard, and soft. In order to obtain vinyl chloride resin molded articles that are flexible and elastic at low to room temperatures, vinyl chloride resin is generally mixed with a plasticizer such as a phthalate ester, a trimellitic acid ester, or a polyester type plasticizer. Among them, when trying to obtain a soft polyvinyl chloride composition with excellent oil resistance and extraction resistance, the molecular weight
External plasticization using a polymeric plasticizer of 10,000 or more is preferable because it is superior in oil resistance and extraction resistance compared to external plasticization using a low molecular plasticizer such as phthalate ester. By the way, when such a polymer plasticizer is blended with polyvinyl chloride obtained by a normal suspension polymerization method, there is a problem in that gelling properties during kneading are deteriorated. This is thought to be because the dispersant used during polymerization forms a film on the particle surface, which acts as a barrier and prevents the absorption of plasticizer, resulting in deterioration of gelling properties during kneading. Ru. This tendency is remarkable in polymer plasticizers with a molecular weight of 10,000 or more. When polyvinyl chloride with a small film, that is, vinyl chloride, is suspended polymerized in an aqueous medium, (a) polymerization is initiated in the presence of lipophilic sorbitan higher fatty acid ester and/or lipophilic polyoxyethylene sorbitan higher fatty acid ester. (b) When the polymerization conversion rate reaches 5 to 40%, polyvinyl chloride produced by adding a water-soluble cellulose derivative is kneaded with a polymeric plasticizer having a molecular weight of 10,000 or more to form a gel. It is known that the chemical properties can be improved (Japanese Patent Application Laid-Open No. 168644/1982), but in actual production, a machine with strong kneading power such as a Banbury mixer is required. However, when kneading with such a strong kneading machine, thermal deterioration becomes severe and the problem arises that the product becomes discolored. In addition, although this solves the problem of using a kneading machine with weak kneading properties such as a two-roll machine or an extruder, there is actually a problem that lumps remain due to insufficient kneading, and further improvement of the resin composition is required. desired. The present inventors have conducted intensive research to obtain a vinyl chloride resin composition that has excellent gelation properties even with weak kneading machines such as two rolls and extruders. When kneading with a molecular plasticizer, it was discovered that if a graft copolymer obtained by grafting polyvinyl chloride with other monomers was added, the gelling properties would be surprisingly improved, and the present invention was realized. completed. That is, the present invention includes 100 parts by weight of polyvinyl chloride, 25 to 200 parts by weight of a polymeric plasticizer, and 99.5 to 70 parts by weight of polyvinyl chloride, vinyl acetate, butyl acrylate, methyl methacrylate, hexene-1, and styrene. This is a vinyl chloride resin composition with good processability, characterized by comprising 2 to 150 parts by weight of a graft copolymer obtained by graft copolymerizing 0.5 to 30 weight % of at least one type of comonomer. The polyvinyl chloride used in the present invention is a homopolymer of vinyl chloride, and for example, sorbitan higher fatty acid ester, polyoxyethylene sorbitan higher fatty acid ester, water-soluble cellulose derivative, polyvinyl alcohol, polyvinylpyrrolidone, gelatin, etc. are used as a dispersing agent. For example, benzoyl peroxide, lauroyl peroxide, caproyl peroxide,
Organic peroxides such as diisopropyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, tertiary butyl peroxybivalate; 2,2'-azobisisobutyronitrile, 2,2'-azobis- 2,4-dimethylvaleronitrile, 2,2'-azobis-4-methoxy-
Preferably, it is obtained by polymerizing vinyl chloride using an azo compound such as 2,4-dimethylvaleronitrile alone or in combination. Examples of polymer plasticizers used in the present invention include polyester polymer plasticizers, ethylene-vinyl acetate-based polymer plasticizers, and polymer plasticizers made of ethylene-vinyl acetate-carbon monoxide copolymers. Mention may be made of molecular plasticizers and modified products thereof. Note that it is desirable to have a molecular weight of 10,000 or more due to problems such as bleeding. Among them, a polymer plasticizer having a molecular weight of 10,000 or more and consisting of a copolymer of ethylene, vinyl acetate, and carbon monoxide is particularly effective in obtaining a polyvinyl chloride composition having oil resistance and extraction resistance. The amount of polymer plasticizer blended is polyvinyl chloride 100
25 to 500 parts by weight is desirable. If it is less than 25 parts by weight, there is almost no plasticizing effect, and
If it is used in an amount exceeding 500 parts by weight, the properties of polyvinyl chloride will be impaired, which is not preferable. The vinyl chloride graft copolymer added in the present invention includes polyvinyl chloride, vinyl acetate, butyl acrylate, methyl methacrylate, hexene-
This is a graft copolymer obtained by graft copolymerizing at least one comonomer of 1 and styrene. Further, the amount of these monomers in the graft copolymer is 0.5 to 30% by weight, and if it is outside this range, the effects of the present invention cannot be obtained. In addition, polyvinyl chloride as the backbone polymer is
Those having a degree of polymerization of 200 to 2,000, preferably 400 to 1,500 are suitably used. The blending amount of the vinyl chloride graft copolymer is preferably 2 to 150 parts by weight based on 100 parts by weight of polyvinyl chloride. Outside this range, the effects of the present invention cannot be obtained. The composition of the present invention includes polyvinyl chloride, a vinyl chloride graft copolymer, and a polymeric plasticizer, as well as a stabilizer, a lubricant, a blowing agent, a filler, an ultraviolet absorber, a pigment, a leveling agent, and a conductive agent, as necessary. carbon,
It is obtained by adding additives such as flame retardants and mixing in a known device such as a Henschel mixer or a ribbon blender. In addition, kneading equipment can range from a Banbury mixer with strong kneading to a two-roll machine or extruder with weak kneading, and can be molded and processed by known methods such as calendaring, melt extrusion, stamping, and injection molding. served. When the composition of the present invention is molded, it has a smooth surface due to the small amount of ungelled particles, and is suitable for use in medical, industrial, and food applications. The present invention will be explained below with reference to Examples. Example 1 1200 kg of pure water in an autoclave with an internal volume of 3000,
1.2 kg of hydroxypropyl methyl cellulose, 600 kg of polyvinyl chloride with a degree of polymerization of 800, and 3.0 kg of α,α'-azobisisobutyronitrile were charged, and after replacing the air inside with nitrogen, 70 kg of vinyl acetate was charged. After reacting at 80°C for 10 hours, unreacted monomers were removed from the reaction product, which was dehydrated and dried.
A powdered graft copolymer resin was obtained. As a result of analysis, this graft copolymer resin contained 10% of components other than vinyl chloride. This graft copolymer resin was blended with polyvinyl chloride having a degree of polymerization of 1050 along with a polymer plasticizer and a Ca-Ba composite stabilizer in the proportions shown in Table 1 to prepare a roll sheet, and the gel level was evaluated. . Examples 2 to 9 In place of polyvinyl chloride with a degree of polymerization of 800 in Example 1,
Use polyvinyl chloride with the polymerization degree shown in Table 1, replace 70 kg of vinyl acetate with the comonomer shown in Table 1, and adjust the polymerization amount of the comonomer to the content shown in Table 1. Graft copolymerization was carried out in the same manner as in Example 1 to obtain a graft copolymer resin. Hereinafter, the gel level was evaluated in the same manner as in Example 1. Comparative Examples 1 to 12 A roll sheet was prepared by blending polyvinyl chloride with a degree of polymerization of 1050, a vinyl chloride graft copolymer, a polymer plasticizer, and a Ca-Ba composite stabilizer in the proportions shown in Table 1. , the gel level was evaluated. Gel test is approximately 0.3mm with 8 inch roll at 160℃
The mixture was kneaded for 10 minutes, and a sheet was taken out and the unmelted polyvinyl chloride particles in a square (10 cm x 10 cm) were visually counted. The unit is the number of pieces. The results of these measurements are shown in Table 1.

[Table] Examples 10 to 12 and Comparative Examples 13 to 15 The vinyl chloride graft copolymer obtained in Example 3, a polymer plasticizer, and Ca- A Ba-based composite stabilizer was blended, and the gel level was evaluated in the same manner as in Example 1. The results of these measurements are shown in Table 2.

[Table] Example 13 Polymerization degree instead of polyvinyl chloride with a polymerization degree of 1050
Example 1 except that 2800 polyvinyl chloride was used.
The gel level was evaluated in the same manner as above, and the result was 90 pieces. Comparative Example 16 Polymerization degree instead of polyvinyl chloride with a polymerization degree of 1050
Comparative example except that 2800 PVC was used.
As a result of evaluating the gel level in the same manner as in 10, it was found to be 800
It was individual. Comparative examples of polyvinyl chloride, vinyl chloride graft copolymers alone, or vinyl chloride copolymers of less than 1 part by weight or more than 150 parts by weight have a gel level of 100 or more, but in the examples of the present invention, none It was also excellent, with less than 100 pieces.

Claims (1)

[Claims] 1 100 parts by weight of polyvinyl chloride, 25 parts by weight of polymer plasticizer
~500 parts by weight, and 99.5-70% by weight of polyvinyl chloride and 0.5-30% by weight of at least one comonomer selected from vinyl acetate, butyl acrylate, methyl methacrylate, hexene-1, and styrene.
Graft copolymer 2 ~
150 parts by weight of a vinyl chloride resin composition with good processability.