JPH08208923A - Polyvinyl chloride resin composition - Google Patents

Abstract

PURPOSE: To obtain a PVC composition excellent in moldability and capable of giving a molding of a good appearance. CONSTITUTION: This polyvinyl chloride resin composition is prepared by adding 0.5-3.0 pts.wt., per 100 pts.wt. polyvinyl chloride resin, calcium carbonate of a diameter of 0.05-0.10μm surface-coated with a fatty acid or its ester to a polyvinyl chloride resin composition containing an organotin stabilizer. This composition has good moldability and can give a molding of a good appearance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinyl chloride resin composition which is excellent in both moldability and appearance of a molded product obtained.

[0002]

2. Description of the Related Art Polyvinyl chloride resin (hereinafter sometimes abbreviated as PVC) is inferior in thermal stability, so that it is molded by adding various thermal stabilizers. As a stabilizer for that,
Stabilizers that use heavy metals such as lead, cadmium, and barium, and organometallic stabilizers that use calcium, zinc, and tin are used. In recent years, the use of the former stabilizer tends to be restricted from the viewpoints of food hygiene, working environment, etc., and the latter stabilizer is often used. Among the latter stabilizers, calcium- and zinc-based stabilizers have a low effect on thermal stability, and thus organotin-based stabilizers are often used as the main stabilizers.

[0003]

However, the composition using the organotin-based stabilizer is apt to adhere to the metal surface of the molding apparatus (for example, the inner surface of the die, the barrel surface of the extruder or the screw surface), and As a result, problems such as "streaking" appearing on the molded product and the gloss becoming poor occur. In addition, if this problem is solved by compounding, the moldability tends to deteriorate.

[0004]

As a result of intensive studies, the present inventors have succeeded in obtaining a polyvinyl chloride resin composition capable of satisfying both moldability and appearance of the obtained molded product. In the polyvinyl chloride resin composition containing an organotin stabilizer, the gist is that the surface of the polyvinyl chloride resin is coated with a fatty acid or a polyester (resin), and the average particle size is 0. .05
The polyvinyl chloride resin composition is obtained by adding 0.5 to 3.0 parts by weight of calcium carbonate having a particle size of 0.10 μm.

The present invention will be described in detail below. In addition, in the following description, "part" indicating the addition ratio means "part by weight" relative to 100 parts by weight of PVC. As the PVC of the composition of the present invention, a vinyl chloride homopolymer, a resin obtained by copolymerizing vinyl chloride with a small amount, for example, about 1 to 10% by weight of a copolymerizable monomer, or a resin obtained by post-chlorinating these resins is used. One kind or a mixture of two or more kinds can be used. Examples of the copolymerizable monomer include ethylene, propylene, isobutene, vinyl acetate, vinyl fluoride, vinylidene chloride, styrene, acrylic acid, and alkyl acrylate.

The degree of polymerization of these PVCs varies depending on the type of molded product to be obtained, but those of about 600 to 2,000, particularly 700 to 1,500 can be preferably used, and the polymerization method Also, suspension polymerization, emulsion polymerization or bulk polymerization can be used.

As the organotin stabilizer to be added to this PVC, various conventionally known ones can be used without particular limitation, but alkyltin malates such as dibutyltin malate and dioctyltin malate or polymers thereof are usable. : Alkyl tin laurate such as dibutyl tin laurate and dioctyl tin laurate: Alkyl tin alkyl mercapto such as dimethyl tin didodecyl mercapto, dibutyl tin didodecyl mercapto, diphenyl tin didodecyl mercapto: Alkyl tin aryl mercapto such as dibutyl tin diphenyl mercapto: Tin mercapto acid salts such as dibutyl tin diisooctyl thioglycolate, dioctyl tin diisooctyl thioglycolate, dibutyl tin di n-octadecyl thioglycolate, dibutyl tin β-mercapto propionate Tel: and the like can be exemplified. The addition amount of the organotin stabilizer may be an amount that can impart sufficient thermal stability to the composition, and is generally 0.2 to 3
Parts, preferably 0.3 to 1.0 parts. This organotin stabilizer includes epoxidized soybean oil as a co-stabilizer,
Epoxy compounds such as epoxidized linseed oil and phosphite compounds such as trialkyl phosphite and alkylaryl phosphite can also be used in combination.

Calcium carbonate, which is a feature of the composition of the present invention, is a particle having an average particle size of 0.05 to 0.10 μm, the surface of which is coated with a fatty acid or a fatty acid ester. With calcium carbonate that does not cover the surface or calcium carbonate with an average particle size that is too large, even if added in a small amount, the moldability is impaired.
Further, if fine particles other than calcium carbonate, such as aluminum silicate, are added in a large amount, there is no problem in molding processability, but the fine particles tend to agglomerate to form lumps, and mechanical strength such as impact strength also decreases.

Examples of the fatty acid or ester coating the surface of the calcium carbonate particles include stearic acid, palmitic acid, or esters of polyglycerin with these fatty acids.

The amount of calcium carbonate added is 0.5 to 3.0.
If it is less than 0.5 part, there is no effect of improving the appearance, and if it exceeds 3.0 parts, the moldability is deteriorated. The preferred range is 1.0 to 2.5 parts.

The composition of the present invention may contain various additives in addition to the above components. For example, ABS resin,
Impact resistance improvers such as MBS resin, chlorinated polyethylene, acrylic rubber based mainly on butyl acrylate; waxes such as paraffin wax, microcrystalline wax, polyethylene wax, octyl alcohol, decyl alcohol, lauryl alcohol, Aliphatic alcohols such as stearyl alcohol; metal soaps such as calcium stearate and zinc stearate; n-
Lubricants such as fatty acid esters such as butyl stearate;
UV absorbers such as salicylate, benzophenone, benzotriazole, etc. can be used, and a small amount of silica, titanium oxide, talc, clay, kaolin, mica and other inorganic fillers can also be used, and other coloring Agents, flame retardants, antistatic agents and the like can be added.

In the composition of the present invention, phthalic acid esters such as di-n-octyl phthalate, di- (2-ethylhexyl) phthalate and diisodecyl phthalate, diisobutyl adipate, di- (2-ethylhexyl) adipate, diisodecyl adipate, etc. Although a conventional plasticizer such as adipic acid ester can be used, in the present invention, the plasticizer having poor fluidity or the plasticizer added is PVC1.
It is particularly effective as a hard or semi-hard composition having a content of 10 parts or less with respect to 00 parts, and is particularly suitable as a non-plastic composition substantially containing no plasticizer.

The composition of the present invention is particularly suitable for melt extrusion molding, and various molded products such as sheets, plates, pipes and profile extruded products can be obtained by a single screw extruder, a twin screw extruder or the like. it can. In particular, since the obtained molded article maintains high mechanical strength, it is suitable for applications requiring tensile strength and impact resistance, and as a hard compound which originally has poor moldability.

[0014]

The present invention will be described below in detail with reference to examples. (Example) The following compositions were mixed with a Henschel mixer, and then a thickness of 2 mm was obtained with a 65 mmφ single-screw extruder.
A mm flat plate was extruded. The extrusion temperature conditions are as follows: the barrel temperature of the extruder is in the range of 140 to 200 ° C., and the die temperature is 16.
The temperature was set in the range of 0 to 190 ° C., and optimum conditions were set according to each composition.

PVC (homopolymer, average degree of polymerization 1300) 100 parts Octyl tin mercapto 0.7 MBS impact modifier 5 Polyethylene wax 0.5 Calcium carbonate 0.5 to 3.0 This calcium carbonate stearinizes the surface. It has an average particle diameter of 0.08 μm coated with an acid.

As a result, when 0.5 part of calcium carbonate has a good moldability, the appearance is a little bad, and when 3.0 part is calcium carbonate, the appearance is good but the moldability is a little poor, and the range is 1.0 to 2.5 parts. So both were good.

(Comparative Example) The same test as in Example 1 was conducted by adding calcium carbonate having an average particle size of 1.25 μm or aluminum silicate having an average particle size of 2 μm, which was not surface-coated, in place of the calcium carbonate of Example. I went.

As a result, the formability of this calcium carbonate was already poor when 0.5 part was added. When 0.5 part of aluminum silicate was added, the moldability was good, but the appearance was not improved, and the moldability was poor at 1.5 parts, which is a slightly improved appearance.

[0019]

EFFECTS OF THE INVENTION According to the present invention, by adding specific calcium carbonate particles to a PVC composition containing an organotin stabilizer, the composition has excellent moldability and appearance of the resulting molded article. Is obtained.

Claims (4)

[Claims] 1. A polyvinyl chloride resin composition containing an organic tin-based stabilizer, wherein the surface of the polyvinyl chloride resin is coated with a fatty acid or a fatty acid ester with respect to 100 parts by weight of the polyvinyl chloride resin. A polyvinyl chloride resin composition obtained by adding 0.5 to 3.0 parts by weight of 10 μm calcium carbonate. 2. The polyvinyl chloride resin composition is a hard or semi-hard composition in which the amount of plasticizer added is 10 parts by weight or less based on 100 parts by weight of the polyvinyl chloride resin. Polyvinyl chloride resin composition. 3. The polyvinyl chloride resin composition according to claim 1, wherein the fatty acid or fatty acid ester coating the surface of calcium carbonate is stearic acid, palmitic acid, or an ester of polyglycerin and these fatty acids. 4. The organotin stabilizer is a tin mercapto stabilizer, and the content thereof is 0.2 to 3 parts by weight, preferably 0.3 to 1.0, based on 100 parts by weight of the polyvinyl chloride resin. The polyvinyl chloride resin composition according to claim 1, 2 or 3 in the range of parts by weight.