JPH0231109B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION Technical Field The present invention relates to vinyl chloride resin compositions. Specifically, the present invention relates to a vinyl chloride resin composition that is highly safe and highly stable against heat. Prior Art Vinyl chloride resin is used for various purposes due to its excellent processability, physiological safety, transparency, low cost, etc. However, vinyl chloride resin has a serious drawback of thermal decomposition. In other words, vinyl chloride resin undergoes a decomposition reaction due to dehydrochlorination under the action of heat, although the details of the reaction mechanism are not clear. In addition, it is further oxidized in the air, causing molecular scission and cross-linking.
Physical properties deteriorate and become brittle. Naturally, the deterioration property of vinyl chloride resins due to heat has caused various problems. For example, when molding using vinyl chloride resin, especially in the case of hard vinyl chloride resin or vinyl chloride resin with a high degree of polymerization, the melt viscosity is high;
Due to the large generation of frictional heat, the resin temperature rises strongly, and as a result, thermal decomposition of the resin is stopped, thermal deterioration occurs inside the molding machine during processing time, and if the resin stagnates inside the molding machine, the stagnation occurs. The resin appears as black foreign matter on the molded product, and when a strong shearing force is applied during the molding process in injection molding, etc., part of the resin turns black, which worsens the appearance of the molded product. The molded product becomes unsuitable as a product, and problems arise such as the need to frequently clean the inside of the molding machine to remove residual resin. The thermal instability of vinyl chloride resin, especially the practical stability required during forming processing,
That is, many studies have been made to improve dynamic thermal stability, and among them, organic compounds of heavy metals such as lead and cadmium are known to have a large stabilizing effect. however,
These organic compounds of heavy metals are highly toxic and harmful to humans, and in recent years, products containing metal stabilizers such as calcium and zinc, which are considered non-toxic, have been attracting attention due to the problem of non-pollution and non-toxicity. Although loons have been used, they are not sufficiently stable to heat. OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide improved vinyl chloride resin compositions. Another object of the present invention is to provide a vinyl chloride resin composition that is highly safe and highly stable against heat. A further object of the present invention is to provide vinyl chloride resin compositions with improved dynamic thermal stability, which is especially necessary during processing. These purposes are based on the general formula R ₁ OCOCH=CHCOOR ₂ () [wherein the formula widths R ₁ and R ₂ are alkyl groups having 4 to 10 carbon atoms] based on 100 parts by weight of vinyl chloride resin. This is achieved by a vinyl chloride resin composition containing 0.5 to 40 parts by weight of an unsaturated aliphatic dicarboxylic acid dialkyl ester represented by the following formula and 0 to 200 parts by weight of other plasticizers. The present invention is a vinyl chloride resin composition in which the unsaturated dicarboxylic acid dialkyl ester is a maleic acid dialkyl ester or a fumaric acid dialkyl ester. The present invention also provides that dialkyl maleate or dialkyl fumarate is
This is a vinyl chloride resin composition in which 0.5 to 40 parts by weight is blended. Furthermore, the present invention is a vinyl chloride resin composition in which the unsaturated aliphatic dicarboxylic acid dialkyl ester is dioctyl maleate, dibutyl maleate, dioctyl fumarate, or dibutyl fumarate. The present invention is a vinyl chloride resin composition containing 2 to 40 parts by weight of dioctyl maleate or dioctyl fumarate. The present invention also provides a vinyl chloride resin composition containing 0.5 to 20 parts by weight of dibutyl maleate or dibutyl fumarate. The present invention is a vinyl chloride resin composition in which the plasticizer is a phthalic acid dialkyl ester (each alkyl group has 6 to 13 carbon atoms). Furthermore, the present invention is a vinyl chloride resin composition in which the plasticizer is an epoxyhexahydrophthalic acid dialkyl ester. DETAILED DESCRIPTION OF THE INVENTION The vinyl chloride resin composition according to the present invention is suitably used for various sheets, pipes, containers, etc. The vinyl chloride resin used in the vinyl chloride resin composition of the present invention includes polyvinylidene chloride and vinyl chloride in addition to a vinyl chloride homopolymer.
There are copolymers with other copolymerizable monomers containing at least 65% by weight, most preferably at least 75% by weight, and the average degree of polymerization thereof is 400%.
~3000, preferably 600-2700, most preferably
It is 800-1700. Comonomers for vinyl chloride include vinylidene chloride, ethylene, propylene, vinyl acetate, vinyl bromide, vinyl fluoride, styrene, vinyltoluene, vinylpyridine, acrylic acid, alkyl acrylates (e.g. methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, etc.), methacrylic acid, alkyl methacrylate (eg, methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, etc.), acrylonitrile, methacrylonitrile, etc. In addition, vinyl chloride resin includes styrene-acrylonitrile copolymer,
A styrene-methacrylonitrile copolymer can be blended. However, the greatest feature of the present invention is that an unsaturated aliphatic dicarboxylic acid dialkyl ester represented by the general formula R ₁ OCOCH=CHCOOR ₂ () is blended with a vinyl chloride resin. Surprisingly, when the unsaturated dicarboxylic acid dialkyl ester is blended with vinyl chloride resin, the thermal deterioration resistance of the vinyl chloride resin is significantly improved, and in particular, the dynamic thermal stability required during processing is particularly excellent. Become. Examples of the unsaturated aliphatic dicarboxylic acid dialkyl ester represented by the general formula include maleic acid dialkyl ester, fumaric acid dialkyl ester, and the like. The alkyl group of the unsaturated aliphatic dicarboxylic acid dialkyl ester has 4 to 4 carbon atoms.
An alkyl of 10 is desired. That is,
If one or both of the unsaturated aliphatic dicarbonate dialkyl esters is an acid, there is a risk of toxicity, and if it exceeds 10, the kneading into vinyl chloride resin becomes poor. Note that the alkyl groups represented by R ₁ and R ₂ in the general formula do not need to be the same, and may be alcohol mixture esters having different chain lengths. In these unsaturated aliphatic dicarboxylic acid dialkyl esters, the alkyl groups of R ₁ and R ₂ in the general formula have 4 to 10 carbon atoms. Further, these alkyl groups may be branched or linear, but are preferably linear. Furthermore, these unsaturated aliphatic dicarboxylic acid dialkyl esters are the most effective in terms of economy as well, and dibutyl maleate, dibutyl fumarate, dioctyl maleate, and dioctyl fumarate are particularly excellent. These unsaturated aliphatic dicarboxylic acid dialkyl esters are added to 100 parts by weight of vinyl chloride resin.
It is blended in an amount of 0.5 to 40 parts by weight. Especially in the case of dioctyl maleate or dioctyl fumarate 2~
40 parts by weight, or 0.5 to 20 parts by weight in the case of dibutyl maleate or dibutyl fumarate,
Produces excellent effects. These unsaturated aliphatic dicarboxylic acid dialkyl esters provide vinyl chloride resin with stability against heat and, depending on the amount thereof, plasticity. Other plasticizers used to further enhance the plasticizing effect include dibutyl phthalate (DBP), dihexyl phthalate (DHP), di-
2-Ethylhexyl phthalate (DOP), G-n
-Octyl phthalate (DnOP), diisooctyl phthalate (DIOP), diheptyl phthalate,
Didecyl phthalate (DDP), diisodecyl phthalate ((DIDP), octyldecyl phthalate,
Phthalate esters such as butylbenzyl phthalate (BBP), trimellitic ester acids such as tributyl trimellitate and trioctyl trimellitate, dioctyl adipate (DOA), dioctyl azelate (DOZ), dioctyl sebacate (DOS), etc. aliphatic polybasic acid esters, tricresyl phosphate (TCP), tricylenyl phosphate (TXP), monooctyl diphenyl phosphate (Santicizer 141), monobutyl dixylenyl phosphate (B-2- X), phosphate esters of trioctyl phosphate (TOF), citric acid esters such as tributyl acetyl citrate, trioctyl acetyl citrate, tributyl citrate, butylphthalylbutyl glycolate (BPBG), etc., generally chlorinated Any material that can be used for vinyl resins can be used, but phthalic acid dialkyl esters (each alkyl group has 6 to 13 carbon atoms) are preferred. When the number of carbon atoms in the alkyl group of these compounds is 6 or less, especially when used for medical purposes, etc.
This is because there is a concern about toxicity, and when the number exceeds 13, the kneading properties of the vinyl chloride resin deteriorate. Further, it is preferable that the alkyl group is linear from the viewpoint of safety. Note that the alkyl groups do not have to be the same, and may be esters of alcohol mixtures having different chain lengths. Furthermore, epoxyhexahydrophthalic acid dialkyl esters having similar alkyl groups are also preferably used as plasticizers. These plasticizers are blended in an amount of 0 to 200 parts by weight, preferably 5 to 150 parts by weight, most preferably 10 to 80 parts by weight, based on 100 parts by weight of the vinyl chloride resin. The vinyl chloride resin composition may contain calcium, zinc, etc. and stearic acid, lauric acid,
Metal soaps such as ricinoleic acid and naphthenic acid, epoxidized animal and vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, lubricants, and other antioxidants are blended. As the plasticizer, it is also possible to use conventionally known plasticizers based on high molecular weight polymers, such as polychloroprene resins, thermoplastic polyurethane resins, etc., by a polymer blend method. Next, the present invention will be explained in more detail with reference to Examples. Examples 1 to 3 and Comparative Example 1 Di-2-ethylhexyl phthalate (DOP) and dioctyl maleate (DOM) were first added to 100 parts by weight of polyvinyl chloride resin having an average degree of polymerization of about 1050.
The parts by weight shown in the table and an appropriate amount of other stabilizers commonly used in vinyl chloride resin compositions were added, stirred with a Henschel mixer to adsorb the plasticizer, and then pelletized with an extruder. In order to examine the dynamic thermal stability of the obtained vinyl chloride resin composition, the resin composition was placed in a 100ml Laboplast Mill (manufactured by Toyo Seiki Seisakusho), and the temperature was set at 180°C and the blade rotation speed was 120r.
The steady torque rise time (decomposition time) was determined when the resin was kneaded under pm conditions and the characteristics during resin processing (kneading torque, resin temperature) were measured. Results first
Shown in the table.

[Table] Specific effects of the invention As stated above, the vinyl chloride resin composition according to the present invention has a
The composition is highly safe and contains 0.4 to 40 parts by weight of an unsaturated aliphatic dicarboxylic acid dialkyl ester represented by the general formula and 0 to 200 parts by weight of other plasticizers. It has excellent stability against heat, has high dynamic thermal stability, and suppresses deterioration due to resin retention inside the processing machine during molding processing, and prevents resin coloring due to interruption of molding processing or molded products due to retained resin. This solves problems such as the occurrence of black foreign matter.

Claims (1)

[Claims] 1. General formula R ₁ OCOCH=CHCOOR ₂ () [However, R ₁ and R ₂ are alkyl groups having 4 to 10 carbon atoms. A vinyl chloride resin composition comprising 0.5 to 40 parts by weight of an unsaturated aliphatic dicarboxylic acid dialkyl ester represented by the following formula and 0 to 200 parts by weight of another plasticizer. 2. The vinyl chloride resin composition according to claim 1, wherein the unsaturated aliphatic dicarboxylic acid dialkyl ester is dioctyl maleate, dibutyl maleate, dioctyl fumarate, or dibutyl fumarate. 3. The vinyl chloride resin composition according to claim 2, which contains 2 to 40 parts by weight of dioctyl maleate or dioctyl fumarate. 4. The medical vinyl chloride resin composition according to claim 2, which contains 0.5 to 20 parts by weight of dibutyl maleate or dibutyl fumarate. 5. The vinyl chloride resin composition according to any one of claims 1 to 4, wherein the plasticizer is a phthalic acid dialkyl ester (each alkyl group has 6 to 13 carbon atoms). 6 Claims 1 to 5 in which the plasticizer is an epoxyhexahydrophthalic acid dialkyl ester
The vinyl chloride resin composition according to any one of Items.