JPH0525209A - Production of vinyl chloride polymer for use in paste processing - Google Patents

Abstract

PURPOSE:To efficiently produce a vinyl chloride polymer for use in paste processing which gives a soft vinyl chloride resin molding which has excellent clarity and retains its clarity and water resistance even after immersion in warm water. CONSTITUTION:100 pts.wt. vinyl chloride or mixture thereof with a monomer copolymerizable therewith is dispersed in an aqueous medium along with 0.05-3.0 pts.wt. alkali metal salt of an alkylsulfosuccinic acid, 0.05-3.0 pts.wt. ammonium salt of an alkylsulfosuccinic acid, and an oil-soluble polymerization initiator. This dispersion is homogenized and subjected to polymerization, to thereby produce a vinyl chloride polymer for use in paste processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for producing a vinyl chloride polymer for paste processing. More specifically, the present invention provides a vinyl chloride polymer for paste processing, which gives a soft vinyl chloride resin molded article capable of maintaining transparency and water resistance before immersion even when immersed in warm water against environmental changes. The present invention relates to a method for efficiently producing a coalescence.

[0002]

2. Description of the Related Art Conventionally, soft vinyl chloride resin molded products obtained by sol processing of vinyl chloride resin paste have been widely used in the fields of thick and thin products because of their excellent workability. Along with this, there has been a demand for one having a high degree of functionality. For example, in the fields of building materials, packaging, automobiles, etc., a soft vinyl chloride resin molded product obtained by processing a vinyl chloride resin paste is required to have excellent transparency, water resistance, and colorability. However, a molded product obtained by conventional vinyl chloride resin paste processing can obtain a product that sufficiently satisfies the required function immediately after molding,
When the environment changes, its function is often impaired, and the product value often decreases. For example, the molded article is a humidification chamber,
If the molded product is taken out after being placed in water, warm water, etc., the transparency is significantly lowered and the appearance of the product is greatly changed. Therefore, in order to avoid such an unfavorable situation, for example, (1) a method of reducing the auxiliary material used in the vinyl chloride paste resin, (2) addition of an additive that promotes each function when the vinyl chloride resin plastisol is prepared And (3) a method of using a polymeric emulsifier excellent in retaining transparency and water resistance in the production of (3) vinyl chloride paste resin, but any of them is sufficiently satisfactory. I can't say. For example, the method (1) for reducing the amount of the auxiliary material is to produce the vinyl chloride paste resin by using a minimum amount of the auxiliary material, or physically or chemically after producing the vinyl chloride paste resin. It is done by removing the agent. However, in the method for producing a vinyl chloride paste resin, a suspension of fine particles of the vinyl chloride resin, that is, a latex of the vinyl chloride resin is generally prepared using an emulsifier and spray-dried. It is not practical to reduce or remove the emulsifying agent, etc. because it hinders the stability of the latex. In addition, the method of adding an additive that promotes each function of (2) is difficult to sufficiently satisfy the required functions, and the original quality of the vinyl chloride paste resin is deteriorated, and further the cost is increased. It has drawbacks such as On the other hand, the method (3) using a polymer emulsifier excellent in retaining each function has the drawbacks that the stability of the latex at the time of production is inferior and the gelation property or coloring property at the time of processing is also inferior.

[0003]

Under the circumstances, the present invention is a soft vinyl chloride resin molded article which has excellent transparency and can retain the transparency before immersion even when immersed in warm water. The object of the present invention is to provide a method for efficiently producing a vinyl chloride polymer for paste processing which gives

[0004]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to achieve the above object, the transparency or water resistance of a molded product obtained by processing a vinyl chloride resin paste sol is impaired by environmental changes. Focusing on the fact that the factor that is caused is in the auxiliary material used in the production of the vinyl chloride paste resin, especially the emulsifier, by polymerizing a specific emulsifier with respect to the raw material monomer, the purpose is The inventors have found what can be achieved and have completed the present invention based on this finding.

That is, the present invention provides vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith.
Disperse parts by weight in an aqueous medium together with 0.05 to 3.0 parts by weight of an alkali metal salt of alkylsulfosuccinic acid, 0.05 to 3.0 parts by weight of an ammonium salt of alkylsulfosuccinic acid, and an oil-soluble polymerization initiator, and homogenize. The present invention provides a method for producing a vinyl chloride polymer for paste processing, characterized by polymerizing and polymerizing.

The present invention will be described in detail below. In the method of the present invention, vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith is used as a raw material monomer. Examples of the copolymerizable monomer include vinyl esters such as vinyl acetate, vinyl propionate, vinyl myristate and vinyl oleate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether, ethylene, propylene and butene. -1, olefins such as pentene-1, styrene,
Examples thereof include aromatic monovinyl compounds such as α-methylstyrene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and vinylidene chloride. These monomers may be used alone or in combination of two or more.

In the method of the present invention, a fine suspension polymerization method is used as a polymerization method. An oil-soluble radical initiator is used as the polymerization initiator in this fine suspension polymerization method, and examples of the oil-soluble radical initiator include dibenzyl peroxide and di-3,5,5-trimethylhexanoyl peroxide. Diacyl peroxides such as dilauroyl peroxide, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, peroxydicarbonates such as di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, t-butyl peroxy. Peroxyesters such as neodecanoate, or organic peroxides such as acetylcyclohexylsulfonyl peroxide, disuccinic acid peroxide, and α, α′-azobisisobutyronitrile, α, α '-
Examples thereof include azo compounds such as azobis-2-methylbutyronitrile and α, α′-azobis-2,4-dimethylvaleronitrile. These polymerization initiators may be used alone or in combination of two or more, and the use amount thereof is appropriately selected depending on the kind and amount of the monomer and the charging system, but it is usually a raw material. Per 100 parts by weight of monomer, 0.
It is selected in the range of 001 to 5.0 parts by weight.

In the method of the present invention, it is necessary to use a combination of an alkali metal salt of alkylsulfosuccinic acid and an ammonium salt as an emulsifier in this fine suspension polymerization. Although the alkali metal salt of alkylsulfosuccinic acid imparts stability to the latex and gives a molded article excellent in thermal stability and transparency, the resulting molded article has a drawback that it is inferior in water resistance. On the other hand, the ammonium salt of alkylsulfosuccinic acid is inferior in the stability of the latex and the thermal stability of the molded product, but can give a molded product excellent in transparency and water resistance.

Therefore, by using the alkali metal salt of alkylsulfosuccinic acid and the ammonium salt in combination at a predetermined ratio as emulsifiers used in the polymerization system, stability is imparted to the latex and transparency and water resistance are excellent. In addition, a vinyl chloride polymer for paste processing can be obtained which gives a molded article in which these functions are not impaired even in an environment with high water content, such as water, hot water, or high humidity. The alkali metal salt of alkylsulfosuccinic acid is preferably a sodium salt or a potassium salt, and the alkyl group in the alkali metal salt or ammonium salt of alkylsulfosuccinic acid preferably has 4 to 20 carbon atoms. Further, the alkali metal salt or ammonium salt of the alkylsulfosuccinic acid may be a monoester salt.
Preferred examples of the alkali metal salt and ammonium salt of alkylsulfosuccinic acid include sodium salt of dioctylsulfosuccinic acid, potassium salt, ammonium salt and sodium salt of dihexylsulfosuccinic acid, potassium salt,
Examples thereof include ammonium salts.

Regarding the amount of the emulsifier used in the method of the present invention, the amount of the alkali metal salt of alkylsulfosuccinic acid is 0.05 to 3.0 parts by weight, and the amount of the alkylsulfosuccinic acid is 100 parts by weight of the raw material monomer. Ammonium salt is used in a proportion of 0.05 to 3.0 parts by weight. If the use ratio of these alkyl sulfosuccinates deviates from the above range, the object of the present invention cannot be sufficiently achieved. In the present invention, other emulsification aids can be used as desired. Examples of the emulsification aid include sorbitan monooleate, sorbitan esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and nonionic properties such as polyoxyethylene alkyl esters. Surfactants may be mentioned. These nonionic surfactants may be used alone or in combination of two or more, and the amount thereof is usually 0.05 to 5.0 parts by weight per 100 parts by weight of the raw material monomer. , Preferably 0.2 to 3.0 parts by weight.

In the fine suspension polymerization method of the present invention, first, in an aqueous medium, the oil-soluble radical initiator, the alkali metal salt of alkylsulfosuccinic acid, the ammonium salt of alkylsulfosuccinic acid, and the emulsification auxiliary used as necessary. The agent and other additives and raw material monomers are added, homogenized by a homogenizer and premixed, and the particle size of oil droplets is adjusted to carry out a polymerization reaction. The homogenized emulsion is heated slowly while stirring, and the polymerization is usually carried out at a temperature in the range of 30 to 80 ° C. After the completion of the polymerization, the vinyl chloride polymer latex can be obtained by uniformly dispersing fine particles of the vinyl chloride polymer having an average particle diameter of about 0.2 to 3 μm with almost no formation of lumps. This latex is usually subjected to a known treatment such as salting out and spray drying, and taken out as a solid. The vinyl chloride polymer obtained in the form of fine powder is
When processed into a paste dispersion liquid (plastisol, organosol, etc.), a molded article having excellent transparency and water resistance can be obtained.

[0012]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. Comparative Example 1 A 10-liter stainless steel autoclave was charged with 6000 g of deionized water and 3 parts of sodium dihexylsulfosuccinate.
0 g, 30 g of lauryl alcohol and 3 g of diisopropyl peroxydicarbonate were charged, degassed under reduced pressure, 3000 g of vinyl chloride was charged and mixed by stirring, and this mixture was homogenized with a homogenizer, and then another deaerated autoclave of 10 liter was degassed. The temperature was raised to 40 ° C. and the polymerization was started. After completion of the polymerization, unreacted monomers were recovered under reduced pressure, and the produced latex was spray-dried and pulverized to obtain a vinyl chloride polymer. The polymer 100 obtained
After 60 parts by weight of dioctyl phthalate was mixed with parts by weight using an Ishikawa type Raikai machine, degassing under reduced pressure was performed to obtain plastisol. This plastisol was applied on a glass plate to a thickness of 300 μm and heated in a hot air circulation type oven at 200 ° C. for 5 minutes. After cooling, the film formed on the glass plate was taken out, and the transparency and the initial coloring resistance were examined. .. Then, the film was immersed in warm water of 30 ° C. for 24 hours, taken out, and quickly wiped off water drops, and then the transparency and the color tone were examined. On the other hand, 57 parts by weight of dioctyl phthalate and 3.1 parts by weight of toner (3 parts by weight of dioctyl phthalate, 0.1 part by weight of titanium white) were added to 100 parts by weight of the above polymer, and a plastisol obtained in the same manner was used to prepare a glass. Form a film with a thickness of 300 μm on the plate, and
After heating for 5 minutes in a hot air circulation type oven at 00 ° C., the film was taken out from the glass plate after cooling, and the color tone was measured with a color difference meter. Then, the film was immersed in warm water of 30 ° C. for 24 hours, taken out, quickly removed water drops, and then measured with a color difference meter. The results are shown in Table 1.

Comparative Example 2 The procedure of Comparative Example 1 was repeated except that potassium dihexylsulfosuccinate was used instead of sodium dihexylsulfosuccinate. The results are shown in Table 1.

Comparative Example 3 The procedure of Comparative Example 1 was repeated except that ammonium dihexylsulfosuccinate was used in place of sodium dihexylsulfosuccinate in Comparative Example 1. The results are shown in Table 1.

Example 1 In Comparative Example 1, 15 g of potassium dihexyl sulfosuccinate and 15 g of ammonium dihexyl sulfosuccinate were used instead of 30 g of sodium dihexyl sulfosuccinate.
The procedure of Comparative Example 1 was repeated except that g was used. The results are shown in Table 1.

Example 2 In Comparative Example 1, 10 g of potassium dihexyl sulfosuccinate and 20 g of ammonium dihexyl sulfosuccinate were used instead of 30 g of sodium dihexyl sulfosuccinate.
The procedure of Comparative Example 1 was repeated except that g was used. The results are shown in Table 1.

[0017]

[Table 1]

Note 1) Color tone: Determined by visual observation. Thermal stability (blackening time): A 200 ° C. gear oven (hot air circulation type) was used to examine changes in the coating film on the glass plate. 2) Haze value (cloudiness): determined by using a direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd. Film thickness 300 μm Color difference measurement: Determined using SM color computer SM-3 manufactured by Suga Test Instruments Co., Ltd. L lightness is shown. a Shows green color. b Yellowish. The closer the absolute value is to 0, the smaller the difference before and after immersion. 3) Latex particle size: 800 from a transmission electron microscope observation photograph
The particle diameters of up to 1000 particles were measured and the average was obtained.

[0019]

INDUSTRIAL APPLICABILITY According to the present invention, a vinyl chloride polymer for paste processing which is excellent in transparency and gives a soft vinyl chloride resin molded article capable of retaining the transparency and water resistance before immersion even when immersed in warm water. Can be manufactured efficiently.

Claims (1)

Claim: What is claimed is: 1. 100 parts by weight of vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith and 0.05 to 3.0 parts by weight of an alkali metal salt of alkylsulfosuccinic acid. And alkyl sulfosuccinate ammonium salt 0.05-3.0
A method for producing a vinyl chloride polymer for paste processing, which comprises dispersing, by weight, and an oil-soluble polymerization initiator in an aqueous medium, homogenizing and polymerizing.