JPH0358365B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polymerization method for obtaining vinyl chloride polymers or copolymers (hereinafter referred to as vinyl chloride polymers) having good color and no odor during processing. More specifically, the present invention relates to a method for emulsion polymerization of vinyl chloride, which uses tertiary octyl peroxyneodecanate as a polymerization catalyst when emulsion polymerizing vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable with vinyl chloride. Vinyl chloride emulsion polymers become a flexible composition by mixing with a plasticizer and applying heat, so they are widely used as flexible vinyl chloride resins. These soft vinyl chloride resins are transparent, opaque, white, or colored to produce a variety of processed products, but recently, particularly light colors have become preferred. However, if the hue of vinyl chloride polymers deviates from white, there is a disadvantage that if a processed product with a light color is produced, the color of the product will not be vivid and will be dull. It was hoped that the color hue would be improved. As a result of studies on this point, the present inventors discovered α-cumyl peroxyneodecanate as a catalyst that provides polymers with improved hue, but this catalyst uses acetophenone during processing of the polymers. It has been found that it has the disadvantage of emitting a fairly strong peculiar odor similar to phenol. Unusual odors produced during processing using heat in an oven or the like can be a serious problem as they cause environmental deterioration and harm the health of workers. As a result of further intensive studies on polymerization methods, the present inventors found that by using tertiary octyl peroxyneodecanate as a polymerization catalyst, vinyl chloride polymers with good color and no odor during processing could be obtained. Heading The present invention has been arrived at. According to the present invention, a hue characterized in that tertiary octyl peroxyneodecanate is used as a polymerization catalyst when emulsion polymerizing vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith. A good method for emulsion polymerization of vinyl chloride. is provided. In the present invention, tertiary octyl peroxyneodecanate is used as a polymerization catalyst, but it may be used in combination with other catalysts in order to equalize the polymerization reaction rate. Other catalysts used in combination include dialkyl peroxy dicarbonates such as diisopropyl peroxy dicarbonate, dioctyl peroxy dicarbonate, dilauryl peroxy dicarbonate, dicetyl peroxy dicarbonate, ditertiary butyl peroxy dicarbonate, etc. Dicarbonate, di(2-ethoxyethyl)peroxydicarbonate, di(2-methoxypropyl)peroxydicarbonate, dibenzylperoxydicarbonate, dicyclohexylpooxydicarbonate, ditertiarybutylcyclohexylperoxydicarbonate, etc. , 2,2'-asobis-2,4-dimethylvaleronitrile, 2,2'-asobis-4-methoxy-2,4-dimethylvaleronitrile and other azo compounds, tert-butyl peroxyneodecanate, ditercia Libutyl oxalate,
Examples include isobutyryl peroxide. However, it is of course essential that tertiary octyl peroxyneodecanate be included in the combination. Although there is no limit to the number of catalysts to be combined, a combination of two to four types of catalysts is usually preferred. The higher the proportion of tertiary octyl peroxyneodecanate in the catalysts used in combination, the better the hue of the vinyl chloride polymers. The proportion of tertiary octyl peroxyneodecanate in the catalyst used in combination is
10 to 100% by weight is preferred, and 20 to 100% by weight is more preferred. In the present invention, the amount of catalyst used in the homopolymerization of vinyl chloride is determined by the type of catalyst, polymerization temperature, heat removal capacity of the polymerization machine (including heat removal capacity of incidental equipment), etc. Generally, the amount of tertiary octyl peroxyneodecanate is 0.005 to 0.5 parts by weight per 100 parts by weight of vinyl chloride, and the amount of the catalyst used in combination is 0.005 to 0.5 parts by weight. If the amount of the catalyst used is less than 0.005 part by weight, the effect as a catalyst will be low, and if it exceeds 0.5 part by weight, it will be difficult to control the polymerization rate and there is a risk that the polymerization reaction will run out of control. Furthermore, in the present invention, the amount of the catalyst used in the copolymerization of vinyl chloride is similarly determined by the type of comonomer, the polymerization temperature, the heat removal capacity of the polymerization machine (including the heat removal capacity of incidental equipment), etc. However, tertiary octyl peroxyneodecanate per 100 parts by weight of vinyl chloride and comonomer is usually
0.005 to 3.0 parts by weight, and 0.005 to 3.0 parts by weight of the catalyst used in combination. If the amount of the catalyst used is less than 0.005 parts by weight, the effect as a catalyst will be low, and if it exceeds 3.0 parts by weight, it will be difficult to control the polymerization rate and there is a risk that the polymerization reaction will run out of control. By using the catalyst system of the present invention, vinyl chloride polymers with good color and no odor during processing can be obtained. The method of the present invention can be applied to paste resin manufacturing methods commonly practiced in the art. That is, the ratio of vinyl chloride to water is generally 80 to 300 parts by weight of water per 100 parts by weight of vinyl chloride, and the polymerization temperature is usually 35 to 70°C. In addition to vinyl chloride, other monomers copolymerizable with vinyl chloride, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexane, 1-heptene, 1-octene, 1-nonene, 1-decene ,1
-undecene, 1-dodecene, 1-tridecene,
α-olefins having 2 to 30 carbon atoms such as 1-tetradecene, acrylic acid or its esters, methacrylic acid or its esters, fumaric acid or its ester acids, maleic acid or its esters, vinyl acetate, vinyl propionate,
Vinyl compounds such as alkyl vinyl ethers and mixtures thereof can be coexisting. In the present invention, known emulsifiers are used. As the emulsifier used in the present invention, those normally used in the polymerization of paste resin can be used without any problem, but examples include alkyl sulfonates, alkylaryl sulfonates, alkyl alcohol sulfate ester salts, fatty acid salts, dialkyl sulfosuccinic acids. One or more types of common anionic surfactants such as salts may be used. These salts are generally alkali metal salts. In addition to anionic surfactants, nonionic surfactants such as glycerin esters, glycol esters or sorbitan esters of higher fatty acids, higher alcohol condensates, higher fatty acid condensates,
Polypropylene condensate etc. and lauryl alcohol are used together as an emulsifier. The total amount of these emulsifiers is 0.1 to 5 parts by weight per 100 parts by weight of monomer. Further, aromatic hydrocarbons, higher aliphatic hydrocarbons, halogenated hydrocarbons such as chlorinated paraffin, PH regulators such as sodium bicarbonate and ammonia, and ordinary polymerization aids such as chain transfer agents may be used in combination. It is also necessary to premix the emulsifier, polymerization initiator, water, vinyl chloride monomer and, if necessary, other polymerization aids prior to the polymerization reaction and then homogenize by applying high shear forces. The homogenization can be carried out using known homogenization methods such as a one-stage or two-stage high-pressure pump, a colloid mill, a homomixer, high-pressure jetting from a nozzle or orifice, and ultrasonic waves. The odor sensory test method was to measure samples prepared by diluting them using the batch air dilution method using the odor bag method using a three-point comparison method, and determine the odor intensity on a six-point scale. Table 1 shows the contents of the six-level odor intensity display method.

[Table] The present invention will be specifically explained below with reference to Examples and Comparative Examples, but these are merely illustrative and do not limit the scope of the present invention. In addition, examples,
Parts in comparative examples are parts by weight. Example 1 Distilled water in a pre-mixing vessel with a volume of 1000 and a stirrer.
450Kg, sodium lauryl sulfate 3Kg,
After charging 6 kg of lauryl alcohol, 0.17 kg of tertiary octyl peroxyneodecanate, and 0.06 kg of dioctyl peroxydicarbonate and purging the space with nitrogen, the pressure inside the container was reduced and 300 kg of vinyl chloride monomer was charged. The mixture was stirred and mixed for 30 minutes while maintaining the temperature inside the container at 30°C. Next, the liquid in the preliminary stirrer was homogenized using a pressurized homogenizer, and then the volume was reduced to 35 mmHgabs using a vacuum pump.
The mixture was charged into a glass-lined polymerization reactor, and the reaction was continued at 50° C. until the pressure reached 5 kg/cm ³ G pressure. After the reaction was completed, unreacted monomers were collected, and the polymer latex was dried with a spray dryer and then ground to obtain a product. The obtained polymer particles have a wide distribution in particle size of 0.2 to 2μ,
It had suitable performance as a paste resin. To 100 parts of this paste resin, 60 parts of dioctyl phthalate, 1 part of an organotin stabilizer, and 2 parts of titanium oxide were added to prepare a plastisol.The plastisol was made to a thickness of 1 mm using an applicator on a ferro plate, and heated in a gear oven at 180°C for 10 minutes. A film was obtained by curing for a minute. No abnormal odor was detected in the gear oven, and the odor intensity was 1 according to the sensory test. When the yellowness was measured using a colorimeter, it was 1.3, and a clear white color was observed visually. Comparative Example 1 A film was obtained in the same manner as in Example 1, except that 0.12 kg of α-cumyl peroxyneodecanate was used instead of 0.17 kg of tertiary octyl peroxyneodecanate. The yellowness was measured to be 1.3, and the white color was bright by visual inspection, but there was an odor similar to phenol in the gear oven, which was thought to be due to the decomposition of α-cumyl peroxyneodecanate, and a sensory test showed that the yellowness was 1.3. The odor intensity was 4. Example 2 Distilled water in a pre-mixing container with a volume of 1000 and a stirrer
450Kg, sodium laurisulfate 3Kg, lauryl alcohol 3Kg, myristyl alcohol 3Kg
After charging 0.22 kg of tertiary octyl peroxyneodecanate and purging the space with nitrogen, the pressure inside the container was reduced and 270 kg of vinyl chloride monomer and 30 kg of vinyl acetate were charged, and the temperature inside the container was brought to 30°C. Keep it
The mixture was stirred and mixed for 30 minutes. Next, the liquid in the preliminary stirrer was homogenized using a pressurized homogenizer, and then charged into a glass-lined polymerization reactor with a capacity of 1000, which was reduced to 35 mmHgabs using a vacuum pump, and reacted at 50°C until the pressure was 5 Kg/cm. The reaction continued until ³ G pressure was reached. After the reaction was completed, unreacted monomers were collected, and the polymer latex was dried with a spray dryer and then ground to obtain a product. The obtained polymer particles had a wide distribution in particle size of 0.2 to 3μ and had suitable performance as a paste range. To 100 parts of this paste resin, 60 parts of dioctyl phthalate, 1 part of an organotin stabilizer, and 2 parts of titanium oxide were added to prepare a plastisol.The plastisol was made into a thickness of 1 mm using an applicator on a ferro plate, and heated in a gear oven at 160°C for 10 minutes. A film was obtained by curing for a minute. No abnormal odor was detected in the gear oven, and the odor intensity was 1 according to the sensory test. The yellowness was measured with a colorimeter and was 1.0.
A clear white color was observed by visual inspection. Comparative Example 2 A film was obtained in the same manner as in Example 2, except that 0.15 kg of α-cumyl peroxyneodecanate was used instead of 0.22 kg of tertiary octyl peroxyneodecanate. The yellowness was 1.1 and the white color was clear when visually inspected, but there was an odor similar to phenol in the gear oven, which was thought to be due to the decomposition of α-cumyl peroxyneodecanate.
The odor intensity according to the sensory test was 4. Comparative Example 3 Polymerization was carried out in the same manner as in Example 1, except that tertiary-butyl peroxyneotordecanoate was used instead of tertiary-octylperoxyneodecanate. The obtained polymer was treated in the same manner as in Example 1 to prepare a film. The yellowness was 3.1, but it had an odor similar to neodecanoic acid, which is thought to be due to decomposition of the catalyst.
The odor intensity was 3.

Claims (1)

[Claims] 1 When emulsion polymerizing vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable with it,
A method for emulsion polymerization of vinyl chloride with a good hue, characterized by using lauryl alcohol as an emulsification aid and a polymerization catalyst containing 20 to 100% by weight of tertiary octyl peroxyneodecanate as a polymerization catalyst.