JPH09176423A - Manufacturing method of vinyl chloride polymer - Google Patents

Abstract

(57) [PROBLEMS] To provide a method for producing a vinyl chloride polymer having a good thermal stability, which is unlikely to cause a decrease in bulk specific gravity due to electrification. SOLUTION: In producing a vinyl chloride polymer,
A slurry containing a vinyl chloride polymer, a cake obtained after dehydrating the slurry or a polymer powder obtained by drying the cake is obtained by adding a compound having a specific structure to the vinyl chloride polymer. 0. to 100 parts by weight of polymer.
001-0.5 weight part is added, The manufacturing method of the vinyl chloride polymer characterized by the above-mentioned.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a vinyl chloride polymer by a suspension polymerization method, and more particularly to a method for producing a vinyl chloride polymer having excellent powder fluidity. Is.

[0002]

2. Description of the Related Art Vinyl chloride polymers are generally produced by a suspension polymerization method, and after separation from a slurry, drying, etc., they are transported by pneumatic transportation and then stored or packed.

However, the vinyl chloride polymer is charged with static electricity due to friction with itself or other substances during transport and bagging, and its fluidity is lowered, so that the vinyl chloride polymer is bulkier than the vinyl chloride polymer immediately after production. Since the specific gravity is reduced, it becomes extremely difficult to handle, and there is a problem that work is seriously hindered. As a method of reducing the adverse effect of such polymer charging, conventionally, there is a method of adding a surfactant to a vinyl chloride polymer or a method of blowing steam into the vinyl chloride polymer to adjust the humidity. There is.

[0004]

However, in the conventional method of adding a surfactant, not only the decrease in bulk specific gravity due to the electrification of the polymer cannot be sufficiently prevented,
Further, it has a drawback that it adversely affects the thermal stability and initial colorability of the polymer. In addition, the method of blowing steam has drawbacks such as an increase in required labor force and complication of equipment.

Therefore, an object of the present invention is to provide a method for producing a vinyl chloride polymer having good quality, by which addition of a specific compound hardly causes a decrease in bulk specific gravity due to charging. It is in.

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that addition of a specific compound causes a decrease in bulk specific gravity due to electrification of a vinyl chloride polymer. The present invention has been completed by finding a method for producing a vinyl chloride polymer which is difficult and has good quality.

That is, according to the present invention, when a vinyl chloride-based monomer is suspension-polymerized in an aqueous medium to produce a vinyl chloride-based polymer, a slurry containing the vinyl chloride-based polymer and the slurry are dehydrated. The cake-like material obtained later or the polymer powder obtained by drying the cake-like material is added with a compound represented by the following formula (1) in an amount of 0.001 to 100 parts by weight with respect to 100 parts by weight of the vinyl chloride polymer. The present invention provides a method for producing a vinyl chloride polymer characterized by adding 0.5 part by weight.

R—OSO ₃ Na (1) (R in the formula represents an alkyl group having 10 to 20 carbon atoms.) Hereinafter, the present invention will be described in detail.

In the present invention, the vinyl chloride polymer is produced by the suspension polymerization method.

Examples of the vinyl chloride polymer in the present invention include vinyl chloride homopolymers and vinyl chloride copolymers.

In the present invention, the vinyl chloride-based monomer for producing the vinyl chloride-based polymer is a vinyl-based monomer copolymerizable with vinyl chloride monomer or vinyl chloride monomer and vinyl chloride monomer. Mixtures with monomers are mentioned. Examples of vinyl monomers copolymerizable with vinyl chloride monomers include alkyl vinyl esters such as vinyl acetate; alkyl vinyl ethers such as cetyl vinyl ether; olefinic monomers such as ethylene and propylene; methyl acrylate. , Acrylic acid alkyl esters such as ethyl acrylate and propyl acrylate; and methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and propyl methacrylate.

Suspension polymerization of the vinyl chloride polymer in the present invention may be carried out by a generally known method, for example, in the presence of a vinyl chloride monomer as a suspending agent and a polymerization initiator. The method of polymerizing in an aqueous medium can be mentioned,
A slurry containing a vinyl chloride polymer can be obtained by such a suspension polymerization method.

In the present invention, a slurry containing a vinyl chloride polymer, a cake obtained after dehydrating the slurry or a polymer powder obtained by drying the cake (1) R is an alkyl group having 10 to 20 carbon atoms, and any compound can be used as long as it is represented by the formula (1).

Examples of the compound represented by the formula (1) in the present invention include sodium decyl sulfate, sodium lauryl sulfate, sodium palmityl sulfate and sodium stearyl sulfate.

The addition amount of the compound represented by the formula (1) in the present invention is 0.001 to 0.5 part by weight based on 100 parts by weight of the vinyl chloride polymer. If the addition amount is less than 0.001 part by weight, it is impossible to prevent the bulk specific gravity from being extremely lowered due to the electrification of the obtained vinyl chloride polymer. Further, even if the amount added exceeds 0.5 parts by weight, the desired effect does not increase any more, which is not economical.

In the present invention, the method of adding the compound represented by the formula (1) is as follows: a slurry containing a vinyl chloride polymer, a cake obtained after dehydrating the slurry, or a cake obtained by drying the cake. Any method can be used as long as it can be added to the obtained polymer powder, and it can be added in the state of powder, solution, dispersion or the like. And since it can be easily and uniformly added, it is preferable to add it in a solution or dispersion liquid. In this case, the solvent for preparing the solution or dispersion liquid of the compound represented by the formula (1) is not particularly limited. , For example, water,
Methanol, ethanol, isopropyl alcohol, acetone or a mixed solvent thereof can be used.

[0017]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.

The polymers obtained in Examples and Comparative Examples were evaluated under the conditions shown below.

-Bulk Specific Gravity Measurement Test- The obtained polymer is allowed to stand in a constant temperature and humidity chamber at a temperature of 23 ° C and a relative humidity of 50% for 48 hours, and then the bulk specific gravity is measured according to JIS K.
It was measured by the method of 6721.

The vinyl chloride polymer left under the same conditions as above for 48 hours was stirred at 60 rpm for 2 minutes with a Brabender planetary mixer, the bulk specific gravity was determined by the same method as described above, and the results were compared to charge. The preventive property was evaluated.

-Heat Stability- 100 parts by weight of the obtained polymer was blended with 1.0 part of tribasic lead sulfate, 1.5 parts of lead stearate and 0.5 part of calcium stearate, and a roll at 190 ° C. After kneading for 5 minutes with a processing machine, a sheet with a thickness of 1 mm is prepared, and this sheet is subjected to 190
It was placed in an oven at ℃ and the time until blackening was measured.

Example 1 100 parts by weight of vinyl chloride monomer, 150 parts by weight of deionized water, 0.1 part by weight of partially saponified polyvinyl alcohol, 0.04 part by weight of 2-ethylhexyl peroxydicarbonate were placed in a stainless steel polymerization vessel. Was charged, polymerization was carried out at a temperature of 57 ° C., and when the pressure in the polymerization vessel reached 6.0 kg / cm ² G, unreacted vinyl chloride monomer was recovered and dehydrated to contain 20% by weight of water. A vinyl chloride polymer cake was obtained.
Vinyl chloride polymer 1 was added to the polymer cake thus obtained.
A 1% aqueous solution of sodium lauryl sulfate was added so that the amount of sodium lauryl sulfate added was 0.01 parts by weight with respect to 00 parts by weight, and then fluid-dried at 70 ° C. for 2 hours to obtain a vinyl chloride polymer.

The evaluation results of the obtained vinyl chloride polymer are shown in Table 1.

The obtained vinyl chloride polymer had excellent antistatic properties and did not deteriorate in thermal stability.

Examples 2 to 5 Vinyl chloride polymers were obtained in the same manner as in Example 1 except that the addition amount and addition conditions of sodium lauryl sulfate were changed to those shown in Table 1.

The evaluation results of the obtained vinyl chloride polymer are shown in Table 1.

The vinyl chloride polymer thus obtained had excellent antistatic properties and did not deteriorate in thermal stability.

Comparative Example 1 Example 1 except that sodium lauryl sulfate was not added.
A vinyl chloride polymer was obtained in the same manner as in.

Table 1 shows the evaluation results of the obtained vinyl chloride polymer.

The obtained vinyl chloride polymer was inferior in antistatic property.

[0031]

[Table 1]

[0032]

INDUSTRIAL APPLICABILITY The present invention relates to a method for producing a vinyl chloride polymer having a good thermal stability, which is unlikely to cause a decrease in bulk specific gravity due to electrification, and has a high industrial value.

Claims (1)

[Claims] 1. A suspension-polymerization of a vinyl chloride monomer or a mixture of vinyl-based monomers having vinyl chloride monomer as a main component (hereinafter referred to as vinyl chloride-based monomer) in an aqueous medium, In producing a vinyl chloride-based polymer, a slurry containing the vinyl chloride-based polymer, a cake obtained after dehydrating the slurry or a polymer powder obtained by drying the cake, the following: 0.001 to 0.5 of the compound represented by the formula (1) is added to 100 parts by weight of the vinyl chloride polymer.
A method for producing a vinyl chloride-based polymer, characterized in that a part by weight is added. _{R-OSO 3 Na (1)} (R in the formula represents an alkyl group having 10 to 20 carbon atoms.)