JPS61192757A - Vinyl chloride resin composition having improved thermal stability - Google Patents

Abstract

PURPOSE:To provide the titled resin compsn. which has greatly improved durable thermal stability and is freed from the problem of initial discoloration, by incorporating predetermined quantities of hydrotalcite and an organotin compd. in a vinyl chloride resin. CONSTITUTION:0.1-20pts.wt. mixture obtd. by blending 10-1pt.wt. organotin compd. [e.g. poly(dibutyltin maleate)] or lead, zinc or Cd salt of an org. acid (e.g. stearic acid) with 1-20pts.wt. hydrous or anhydrous hydrotalcite composed of a double salt of Mg and Al is blended with 100pts.wt. vinyl chloride resin contg. 0.05-20wt% carboxyl group obtd, by copolymerizing vinyl chloride and a carboxyl group-contg. comonomer to obtain the desired vinyl chloride resin compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a vinyl chloride resin composition with improved thermal stability, and more particularly, to a carboxyl group-containing vinyl chloride resin containing hydrotalcite and other specific The present invention relates to a vinyl chloride resin composition that contains a metal compound and has significantly improved initial coloring and sustained heat stability.

(Prior Art) It is well known that in the molding process of vinyl chloride resin, a heat stabilizer is always required, regardless of whether it is hard or soft, in order to suppress thermal decomposition.

On the other hand, vinyl chloride resin has well-balanced physical properties.

It is one of the most widely used synthetic resins due to its cost, and as the required functions expand, many modified vinyl chloride resins are also being developed and applied. Vinyl chloride resin containing carboxyl groups, which is one of the modified vinyl chloride resins, has poor thermal stability due to the acid groups it contains. etc.), it is difficult to suppress thermal decomposition during molding, and
If you try to forcefully maintain thermal stability, you will need several times more stabilizers than ordinary vinyl chloride resins, resulting in a significant increase in cost.

(Problems to be Solved by the Invention) As a result of intensive research in order to solve the above-mentioned drawbacks, the present inventors have found that by adding no-hydrotalcite and other specific metal compounds to carboxyl group-containing vinyl chloride resin, It was discovered that the initial color tone and sustained thermal stability are comparable to those of vinyl chloride homopolymer, and based on this knowledge, the present invention was completed.

(Means for Solving the Problems) Thus, according to the present invention, per 100 parts by weight of carboxyl group-containing vinyl chloride resin, (!) hydrotalcite and (2) lead as an organotin compound or an organic acid.

There is provided a vinyl chloride resin composition with improved thermal stability, which contains a zinc or cadmium salt in a total amount of 0.1 to 20 parts by weight of (1) and (2).

(Effects of the Invention) The carboxyl group-containing vinyl chloride resin used in the present invention includes a copolymer of vinyl chloride and a carboxylic acid-containing comonomer copolymerizable therewith, and a copolymer of vinyl chloride and a carboxylic acid ester. Examples include a polymer obtained by copolymerizing and then hydrolyzing, or a vinyl chloride polymer prepared by addition reaction with a carboxylic acid-containing compound. The content of carboxyl groups is usually O, OS to 20% by weight.

Further, the hydrotalcite in (1) is a double salt of Mg and AJ, and may be a hydrate or an anhydride.

Examples of the organic tin compound (2) include poly(diptyltin malate) and dibutyltin bis(alkyl maleate).

Alkyl such as dioctyltin bis(alkyl maleate), dibutyltin bis(alkyl laurate), dibutyltin bis(alkyl mercaptide), dimethyltin bis(alkyl mercaptide), dioctyltin bis(alkyl mercaptide), etc. In addition to tin malate, laurate, and mercaptide, alkyl tin mercapto acid ester salts, alkyl ester tin malate, and the like can be mentioned.

(2) The organic acid lead, zinc or cadmium salts include stearic acid, lauric acid, and octylic acid.

Examples include lead, zinc, and cadmium metal salts of saturated or unsaturated fatty acids such as palmitic acid.

These (2) organic tin compounds and organic acid lead, zinc, and cadmium salts may be used alone or in a mixture of two or more kinds of compounds.

The ratio of hydrotalcite to metal compound (2) is 1:10 to 20:1. A more preferable ratio is 1:5-1
The ratio is 0:1.

The total amount of hydrotalcite and the metal compound (2) added to 10 parts by weight of the carboxyl group-containing vinyl chloride resin is o, i to 20 parts by weight, preferably 0.2 to 10 parts by weight.
Parts by weight. If it is less than 0.1 part by weight, the effect of improving initial color tone and sustained thermal stability will be small, and if it is added in excess of 20 parts by weight, it will only increase the cost and no improvement effect proportional to the amount added can be expected.

The method of mixing the carboxyl group-containing vinyl chloride resin with the hydrotalcite (1) and the metal compound (2) is not particularly limited, and (1) and (2) may be added during or at the end of the polymerization of vinyl chloride. Alternatively, the three materials may be powder blended in the same manner as in the usual method of mixing additives.

When producing the vinyl chloride resin composition of the present invention, as in the case of general vinyl chloride resin, plasticizers, other stabilizers, lubricants, fillers, antioxidants, ultraviolet absorbers, processing aids, blowing agents, Pigments, flame retardants.

Various additives such as impact resistance aids can be added as necessary. Further, other polymers such as rubber and plastic may be mixed.

Furthermore, a metal compound or a basic compound may be added for the purpose of neutralizing the carboxylic acid of the carboxyl group-containing vinyl chloride resin.

(Example) The present invention will be described in more detail with reference to Examples below. In addition, parts and parts in the examples are based on weight unless otherwise specified.

Example 1 Vinyl chloride and acrylic acid were suspension copolymerized to obtain 1% acrylic acid. Carboxyl group-containing vinyl chloride resin with an average degree of polymerization of 1.050 (to 100 parts of A3, 0.3 parts of butyl stearate, 3 parts of epoxidized soybean oil, and the amount of hydrotalcite (manufactured by Kyowa Kagaku Co., Ltd.) shown in Table 1) A sheet was obtained by kneading a vinyl chloride resin composition to which Miser 1) and other stabilizers were added using a heated roll at 170°C for 3 minutes.The desired initial coloring of the sheet was determined, and this sheet was It was heat aged in a °C gear oven and the time until decomposition blackening was measured.

On the other hand, as a comparative example, a similar experiment was carried out using a vinyl chloride homopolymer resin (Zeon IQ3EP manufactured by Nippon Zeon Co., Ltd., average degree of polymerization 1,050) instead of the carboxyl group-containing vinyl chloride resin. went. The results are shown in Table 1.

From Table 1, it can be seen that even a carboxyl group-containing polymer exhibits initial and sustained thermal stability comparable to vinyl chloride homopolymer when the two types of stabilizers of the present invention are added together. .

Example 2 Di-2-ethylhexyl phthalate as a plasticizer
The same experiment as in Example 1 was conducted, except that 0 part of the solution was further added and the hot roll temperature was set at 150°C. The results are shown in Table 2.

Claims (1)

[Claims] Per 100 parts by weight of carboxyl group-containing vinyl chloride resin, (1) hydrotalcite and (2) organotin compound,
Or a vinyl chloride resin composition with improved thermal stability, characterized in that it contains 0.1 to 20 parts by weight of lead, zinc or cadmium salts of organic acids as the total amount of (1) and (2).