JPH0651753B2 - Vinyl chloride resin manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention can produce a vinyl chloride resin having preferable characteristics as obtained by emulsion polymerization in a preferable form as obtained by suspension polymerization. The present invention relates to a method for producing a vinyl chloride resin which has a small particle size on a can wall, is easy to control the particle size, and has a sharp particle size distribution.

"Prior Art" A vinyl chloride polymer produced by an emulsion polymerization method has fine polymer particles and excellent processability.

On the other hand, by the suspension polymerization method, when the vinyl chloride polymer is produced, since the particles produced are coarse, dehydration after the completion of the polymerization reaction, washing, thermal stability of the obtained polymer with easy drying, It has excellent electrical properties, transparency and weather resistance, and is easy to handle during processing.

An attempt to produce a vinyl chloride resin having preferable properties as obtained by emulsion polymerization in a preferable form such as a polymer obtained by suspension polymerization is known as disclosed in, for example, Japanese Patent Publication No. 45-30834. is there. According to this publication, the total amount of the polymer to be finally obtained is 5
About 90% is produced by the emulsion polymerization method, and then water, a suspending agent, and an oil-soluble polymerization initiator are added to the reaction system to produce the rest of the polymerization by the suspension polymerization method. This known method has various characteristics similar to those of the vinyl chloride resin produced by emulsion polymerization, and the same post-treatment as suspension polymerization can be carried out, but the particle size distribution of the obtained polymer is not constant. ,
In addition, there is a drawback that the particle size distribution is considerably wide, and it is not always satisfactory in the present processing field of vinyl chloride resin, which is rapidly progressing in technology. Specifically, the method is such that, after being obtained by the emulsion polymerization method, the coarse particles by-produced in the latex remain as they are, and the latex agglomerated particles are not controlled at the latex stage. The vinyl chloride resin produced by suspension polymerization has a wide particle size distribution, and its swing range is large, which causes formation of so-called lumps in the formed product, causing fish eyes, which cannot be put to practical use. There were many. Further, the polymer-scale can wall adhesion was remarkable during suspension polymerization.

"Problems to be Solved by the Invention" The inventors of the present invention will be able to utilize the characteristics of the prior art as they are, and obtain a vinyl chloride resin having preferable properties as obtained by emulsion polymerization by suspension polymerization. Can be produced in various preferred forms, less adhesion to the can wall, easy to control particle size, and conducted diligent research on a method for producing a vinyl chloride resin having a sharp particle size distribution,
The present invention has been reached.

"Means for Solving Problems" Therefore, the gist of the present invention is to produce a vinyl chloride polymer latex by an emulsion polymerization method or a fine suspension polymerization method, and produce a by-product during the production of the latex. After removing coarse particles of 60 mesh or more, the latex is broken by adding an electrolyte to form an aggregated latex,
A method for producing a vinyl chloride-based resin, which comprises suspension-polymerizing vinyl chloride or a mixture of vinyl chloride and a vinyl-based monomer copolymerizable therewith in the presence of the agglomerated latex.

The present invention will be described in detail below.

Monomers to which the method of the present invention can be applied include vinyl chloride alone and a combination of vinyl chloride and one or more vinyl-based monomers copolymerizable therewith. Examples of the vinyl-based monomer here include oil-soluble monomers such as vinyl acetate, styrene, acrylonitrile, acrylic acid ester, methacrylic acid ester, and ethylene; water-soluble acrylic acid, methacrylic acid, maleic acid, crotonic acid, and the like. Examples of the organic monomer include inorganic salts of vinylic monomers such as sodium acrylate, sodium fumarate and calcium acrylate.
Further, as the above-mentioned monomer, a vinyl-based monomer having a polyfunctional group copolymerizable with vinyl chloride, such as divinylbenzene, diallyl phthalate, diallyl maleate, or the like can be applied. The vinyl-based monomer having these polyfunctional groups provides a polymer having a crosslinked structure.

In order to effectively achieve the present invention, it is first necessary to carry out emulsion polymerization or fine suspension polymerization. Vinyl chloride alone,
Alternatively, vinyl chloride and a desired monomer selected from the above monomer group, and water, an emulsifier and a water-soluble polymerization initiator, or an oil-soluble polymerization initiator, and in some cases, a pH adjuster may be added to the reactor, Polymerization is carried out after replacement with active gas.

A water-soluble emulsifier is suitable as an emulsifier that can be used in emulsion polymerization, and an anionic emulsifier is particularly desirable. The amount of the emulsifier is 2.0 per 100 parts by weight of the monomer.
Less than or equal to parts by weight is desirable.

Hydrogen peroxide, potassium persulfate, ammonium persulfate and the like are used as the water-soluble polymerization initiator.

As the oil-soluble polymerization initiator, an initiator that generates a free radical such as benzoyl peroxide, lauroyl peroxide, and di-tert-butyl peroxide is used. Further, an oxidation-reduction system (redox) initiator can also be used.

The polymerization rate of the monomers initially charged using the above composition is 80% or more, and the coarse particles of 60 mesh or more are removed from the latex obtained by polymerizing by emulsion polymerization method or fine suspension polymerization method. , Suspending agents and electrolytes are added to break the latex and form an agglomerated latex.

When destroying the latex, water is added so that the solid content ratio is 25% or less, and the suspending agent is 0 to polyvinyl chloride.
0.5% is added, and the electrolyte is gradually added and agglomerated while stirring under the temperature condition of 30 to 60 ° C.

As the suspending agent, those generally used in suspension polymerization can be used. For example, various saponified products of polyvinyl acetate,
Examples thereof include various water-soluble cellulose derivatives, maleic acid copolymers, gelatin and the like, and these can be used alone or in combination of two or more kinds. Further, these suspending agents may be used in combination with a certain kind of surfactant.

As the electrolyte, calcium chloride, calcium acetate, a water-soluble alkali metal or alkaline earth metal salt, or the like is used.

Part or all of the agglomerated latex obtained as described above, vinyl chloride alone or a desired monomer selected from vinyl chloride and the above monomer group, and water, a suspending agent and an oil-soluble polymerization initiator. Was placed in a reactor, the atmosphere was replaced with an inert gas, and then suspension polymerization was carried out.

As the suspending agent and the oil-soluble polymerization initiator in the suspension polymerization, those mentioned above can be used.

As described above, the method of the present invention is characterized by combining the emulsion polymerization method or the fine suspension polymerization method and the suspension polymerization method, and the polymerization conditions of the emulsion polymerization method or the fine suspension polymerization method and the suspension polymerization method are It can be changed arbitrarily. For example,
The polymerization temperature may be different, or the polymerization degree of the polymer obtained by the emulsion polymerization method or the fine suspension polymerization method and the polymerization degree of the polymer obtained by the suspension polymerization method may be different. Further, during the polymerization by the emulsion polymerization method or the fine suspension polymerization method and the suspension polymerization method, the polymerization can be continued while adding the monomer stepwise or continuously to the reaction system. In the case of producing a copolymer, the polymerization by the emulsion polymerization method or the fine suspension polymerization method and the polymerization by the suspension polymerization method may be performed with different monomer compositions.

The polymer obtained by the method of the present invention is different from a simple mixture of fine particles produced by an emulsion polymerization method or a fine suspension polymerization method and coarse particles produced by a suspension polymerization method, and has suitable properties brought by each polymerization method. It also has. First, when the polymerization is carried out by the emulsion polymerization method, ordinary fine particles of 2 microns or less are obtained according to the reaction mechanism of the usual emulsion polymerization.

Also, fine particles of 2 microns or less can be obtained by fine suspension polymerization. Destroy the latex containing these fine particles,
When agglomerated latex is further subjected to suspension polymerization, a polymer produced in the suspension polymerization step is wrapped with agglomerated particles derived from the agglomerated latex so as to be obtained by suspension polymerization. (Micron) size. Therefore, salting out as in the usual emulsion polymerization method or fine suspension polymerization method is not required after the completion of the reaction, and dehydration, washing and drying can be easily carried out as in the usual suspension polymerization method.

Effects of the Invention The method of the present invention and the vinyl chloride resin obtained by the method of the present invention have the following excellent characteristics.

1 In the prior art, the particle size distribution was not constant and spread over a wide range, but the present invention makes the particle size distribution sharp and easy to control.

2 Because the particle size distribution became sharper, fish eyes (hereinafter referred to as FE) were reduced compared to conventional ones.

3 The polymer wall adhesion to the can wall was remarkable during suspension polymerization, but it was reduced in the present invention.

4 The polymer obtained in the present invention has good gelation property and thus is excellent in processability.

Examples Next, embodiments of the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

Example 1 Water 1000 g Vinyl chloride 500 g Sodium lauryl sulfate 0.5 g Potassium persulfate 0.3 g Sodium bisulfite 0.3 g Sodium bicarbonate 0.4 g The above composition was added to a stainless steel autoclave equipped with a stirrer with a volume of 3 l and replaced with nitrogen. After that, emulsion polymerization was carried out at 58 ° C. for 5 hours under stirring at 200 rpm, and then unreacted vinyl chloride was separated by degassing operation. The polymerization rate of the initially charged monomer was 90%, and a latex with a solid content of 30% containing fine particles having a particle size of 0.2 micron was obtained. I had it.

The latex was diluted with water to a solid content of 25%, 30 ml of a 2% aqueous solution of polyvinyl alcohol was added, and a calcium chloride aqueous solution was gradually added while stirring at 500 rpm with a separately prepared stainless steel autoclave equipped with a stirrer at a temperature of 30 ° C. In addition, aggregation was carried out. The particle size distribution of the agglomerated particles in this agglomerated latex was measured by a centrifugal sedimentation type particle size distribution analyzer. The parallel particle size was 150 microns.

Subsequently, using the agglomerated latex, 300 g of water, 300 g of agglomerated latex, 300 g of vinyl chloride monomer, 300 g of polyvinyl alcohol 2% liquid, 10 g of lauroyl peroxide, 2.1 g of water were added to a 3-liter stainless steel autoclave equipped with a stirrer, and suspension polymerization was performed at 58 ° C. for 8 hours. I did. After the completion of the polymerization reaction, the dechlorinated vinyl monomer was washed, dehydrated and dried to obtain a polyvinyl chloride resin having an average degree of polymerization of 1050. At this time, the total amount of polyvinyl chloride was 500 g.

Further, almost no sticking to the can wall of the stainless steel autoclave equipped with a stirrer was observed. The average particle diameter of the obtained polyvinyl chloride is 150 microns and the particle size distribution is shown in Table 1.

Next, a sheet was prepared from this polyvinyl chloride using the conventional method with the following compounding amounts, and F.I. When E (fish eye) was measured, it was 1 piece / 100 cm ² . For comparison, a polyvinyl chloride obtained by suspension polymerization was prepared into a sheet in the same manner as described above in F.A.C. without using the latex obtained by the emulsion polymerization method of Example 1. When E is measured, 7 pieces / 1
It was 00 cm ² .

Polyvinyl chloride 100 parts by weight Plasticizer (DOP: di-2-ethylhexyl phthalate) 50 Stabilizer 1 Carbon 0.5 Also, 3 parts by weight of dibutyltin maleate is added to 100 parts by weight of this polyvinyl chloride and mixed with a heating roll. After kneading,
Tested for thermal stability in a 180 ° C gear oven,
The polymer obtained in this example was colored light yellow in 90 minutes, and although the degree of coloring was slightly inferior to that of the polymer prepared by the suspension polymerization method on the market, it was colored by the emulsion polymerization method on the market which was similarly colored in 40 minutes. It showed much better thermal stability compared to the polymer.

In addition, F. The gelation time at 170 ° C. was measured by a Brabender plastograph using the same composition as in the measurement method of E. As a result, it was 80 seconds. The gelling time of the obtained polymer having an average degree of polymerization of 1050 was 150 seconds. The results show that the processability of the polymer obtained by the method of the present invention is far superior to that obtained by the commercially available suspension polymerization method.

Comparative Example 1 The latex obtained in Example 1 was passed through 100 mesh, diluted with water to a solid content of 25%, 30 ml of 2% aqueous solution of polyvinyl alcohol was added, and the latex was used without coagulation.

Water 300 g Latex 1000 g Vinyl chloride monomer 300 g Polyvinyl alcohol 2% liquid 10 g Lauroyl peroxide 2.1 g Each was added to a 3-liter stainless steel autoclave equipped with a stirrer, and suspension polymerization was carried out at 58 ° C. for 8 hours. After completion of the polymerization reaction,
A lot of stainless steel autoclave with stirrer adheres to the can wall,
The wastewater becomes cloudy and the amount of polyvinyl chloride in the wastewater is 25g.
Met. The amount of polyvinyl chloride obtained at this time is 40
It was 0 g, and the average particle diameter was 300 μm, which was very coarse. The particle size distribution is shown in Table 2.

If the latex is not aggregated and polymerized, the wastewater becomes cloudy,
Further, good polyvinyl chloride was not obtained, and Comparative Example 1 cannot be said to be an appropriate polymerization.

Example 2 1000 g of latex obtained by the same method as in Example 1
After passing through 100 mesh, dilute with water to a solid content of 25%, add 30 ml of 2% aqueous solution of methylcellulose,
Under a temperature condition of 30 ° C., a separately prepared stainless steel autoclave equipped with a stirrer was stirred at 500 rpm to gradually add an aqueous calcium chloride solution to cause aggregation. When the particle size distribution of the agglomerated particles in this agglomerated latex was measured by a centrifugal sedimentation type particle size distribution analyzer, the average particle size was 150 microns.

Subsequently, using the agglomerated latex, 300 g of water, 1000 g of agglomerated latex, 300 g of vinyl chloride monomer 300 g, methylcellulose 10 g, and 2.1 g of lauroyl peroxide were added to a 3-liter stainless steel autoclave equipped with a stirrer, and suspension polymerization was carried out at 58 ° C. for 8 hours. After the completion of the polymerization reaction, the dechlorinated vinyl monomer was washed, dehydrated and dried to obtain a polyvinyl chloride resin having an average degree of polymerization of 1050. At this time, the total amount of polyvinyl chloride was 500 g.

Also, the adhesion of the stainless steel autoclave with a stirrer to the can wall is
It was hardly seen.

The average particle diameter of the obtained polyvinyl chloride was 150 microns, and the particle size distribution is shown in Table 3.

Next, a sheet was prepared from this polyvinyl chloride using the conventional method with the following compounding amounts, and F.I. When E is measured, 3 pieces / 1
It was 00 cm ² . For comparison, polyvinyl chloride obtained by carrying out suspension polymerization without passing the latex obtained by the emulsion polymerization method of Example 2 was similarly prepared into a sheet,
F. When E was measured, it was 10 pieces / 100 cm ² .

Polyvinyl chloride 100 parts by weight Plasticizer (DOP: di-2-ethylhexyl phthalate) 50 Stabilizer 1 Carbon 0.5 Also, 3 parts by weight of dibutyltin maleate is added to 100 parts by weight of this polyvinyl chloride and mixed with a heating roll. After kneading, 1
As a result of testing the thermal stability in a gear oven at 80 ° C., the polymer obtained in this example was colored a pale yellow in 85 minutes, and its coloring degree was slightly inferior to that of the polymer prepared by the suspension polymerization method on the market. However, it showed much better thermal stability as compared to the commercially available emulsion polymerization polymer which was similarly colored at 40 minutes.

In addition, F. Using a formulation similar to that used to measure E,
The gelation time was measured by Brabender Plastograph to be 75 seconds, and for comparison, the gelation time of a polymer having an average degree of polymerization of 1050 obtained by a commercially available suspension polymerization method was 150 seconds. there were. The results show that the processability of the polymer obtained according to the present invention is far superior to that of the polymer obtained by the commercially available suspension polymerization method.

Example 3 Water 1200 cc Vinyl chloride 600 g Sodium lauryl sulfate 0.7 g Potassium persulfate 0.4 g The above plastics were added to a stainless autoclave equipped with a stirrer having a volume of 3 l, and after purging with nitrogen, the mixture was stirred at 200 rpm at 58 ° C. for 5 After emulsion polymerization for a period of time, unreacted vinyl chloride was separated by degassing operation. Initially, the polymerization rate of the charged monomers was 90%, and a latex having a solid content of 30% containing fine particles having a particle diameter of 0.2 μm was obtained. Thereafter, the same procedure as in Example 1 was carried out to cause aggregation.

Subsequently, using the coagulated latex, 350 g of water, 900 g of coagulated latex, 600 g of vinyl chloride monomer 600 g, 2% solution of polyvinyl alcohol, 8 g of lauroyl peroxide were added to a 3 L stainless steel autoclave equipped with a stirrer, and suspension polymerization was carried out at 58 ° C. for 8 hours. After completion of the polymerization reaction, devinyl chloride monomer, washed, dehydrated and dried,
A polyvinyl chloride resin having an average degree of polymerization of 1050 was obtained. At this time, the total amount of polyvinyl chloride was 740 g, and almost no adhesion to the can wall of the stainless steel autoclave equipped with a stirrer was observed.

The obtained polyvinyl chloride had an average particle size of 100 microns, and the particle size distribution is shown in Table 4.

This polyvinyl chloride was treated with F.V. When E was measured, it was 1 piece / 100 cm ² .

The polymer obtained in this example was treated with 1 in the same manner as in Example 1.
When the gelation time was measured at 70 ° C., it was 80 seconds as in Example 1. This result shows that the processability of the polymer obtained according to the present invention is far superior to that of the polymer obtained by the commercially available suspension polymerization method.

Also, 3 parts by weight of dibutyltin maleate was added to 100 parts by weight of this polyvinyl chloride, and the mixture was kneaded with a heating roll and then 1
As a result of testing the thermal stability in a gear oven at 80 ° C., the polymer obtained in this example was colored light yellow in 90 minutes, and its coloring degree was slightly inferior to that of the polymer prepared by the suspension polymerization method on the market. At 40 minutes showed much better thermal stability as compared to a similar emulsion-polymerized polymer which was similarly colored.

Example 4 Water 1000 g Vinyl chloride 475 g Vinyl acetate 25 g Sodium lauryl sulfate 0.5 g Potassium persulfate 0.3 g Sodium bisulfite 0.3 g Sodium bicarbonate 0.4 g The above composition was added to a stainless steel autoclave with a stirrer having a volume of 3 l and replaced with nitrogen. After carrying out, the emulsion polymerization was carried out at 58 ° C. for 5 hours under stirring at 200 rpm, and then unreacted vinyl chloride and vinyl acetate were separated by degassing operation. The polymerization rate of the initially charged monomer was 90%, and a latex with a solid content of 30% containing fine particles having a particle size of 0.2 micron was obtained. I had it.

1000 g of the latex was diluted with water to a solid content of 25%, 30 ml of a 2% polyvinyl alcohol solution was added, and
While stirring at 500 rpm in a separately prepared stainless steel autoclave equipped with a stirrer under the temperature condition of 0 ° C., a calcium chloride solution was gradually added to cause aggregation. When the particle size distribution of the agglomerated particles in this agglomerated latex was measured by a centrifugal sedimentation type particle size distribution analyzer, the average particle size was 150 microns.

Subsequently, using the coagulated latex, 300 g of water, 300 g of coagulated latex, 300 g of vinyl chloride monomer 300 g, 2% liquid of polyvinyl alcohol, 10 g of lauroyl peroxide and 2.1 g of lauroyl peroxide were added to a 3-liter stainless steel autoclave equipped with a stirrer, and suspension polymerization was carried out at 58 ° C. for 8 hours. After the completion of the polymerization reaction, a polyvinyl chloride resin was obtained by washing with vinyl chloride, washing, and dehydrating and drying. At this time, the total amount of polyvinyl chloride was 500 g.

Further, almost no sticking to the can wall of the stainless steel autoclave equipped with a stirrer was observed.

The average particle diameter of the obtained polyvinyl chloride was 150 microns, and the particle size distribution is shown in Table 5.

Next, a sheet was prepared from this polyvinyl chloride using the conventional method with the following compounding amounts, and F.I. When E was measured, 1 piece / 1
It was 00 cm ² . For comparison, a polyvinyl chloride obtained by carrying out suspension polymerization without passing the latex obtained by the emulsion polymerization method of Example 4 was similarly prepared into a sheet,
F. When E was measured, it was 7 pieces / 100 cm ² .

Polyvinyl chloride 100 parts by weight Plasticizer (DOP: di-2-ethylhexyl phthalate) 50 Stabilizer 1 Carbon 0.5 Also, 3 parts by weight of dibutyltin maleate is added to 100 parts by weight of this polyvinyl chloride and mixed with a heating roll. After kneading, 1
As a result of testing the thermal stability in a gear oven at 80 ° C., the polymer obtained in this example was colored light yellow in 80 minutes, and its coloring degree was slightly inferior to that of the polymer prepared by the suspension polymerization method on the market. At 40 minutes showed much better thermal stability as compared to a similar emulsion-polymerized polymer which was similarly colored.

In addition, F. Gelation time was determined by Brabender Plastograph using a formulation similar to that used for the measurement of E to be 75 seconds, the average polymerization obtained by the suspension polymerization method commercially available for comparison. The gelling time of the polymer having a temperature of 1050 was 150 seconds. The results show that the processability of the polymer obtained according to the present invention is far superior to that of the polymer obtained by the commercial suspension polymerization method.

Example 5 Water 1000 cc Lauroyl peroxide 9 g Sodium lauryl sulfate 6 g Lauryl alcohol 3 g The above composition was added to a stainless steel autoclave with a stirrer having a volume of 3 and replaced with nitrogen, and then vinyl chloride 600.
g was added and kept at 35 ° C. with stirring at 200 rpm. After uniformly stirring, the mixture was transferred to a 3 liter stainless steel autoclave equipped with a stirrer, which had been previously replaced with nitrogen, while being dispersed into a desired droplet size using an emulsifier. After the transfer of the dispersion liquid was completed, the temperature of the reaction tank was raised to 58 ° C. to carry out fine suspension polymerization. A latex of solid content% containing fine particles having a particle size of 0.4 micron was obtained. Since coarse particles were contained in this latex, 100 mesh was used.

1000 g of the latex was diluted with water to a solid content of 25%, 32 ml of a 2% aqueous solution of polyvinyl alcohol was added,
While stirring at 500 rpm in a separately prepared stainless steel autoclave equipped with a stirrer under the temperature condition of 30 ° C., a calcium chloride aqueous solution was gradually added to cause aggregation. The particle size distribution of the agglomerated particles in this agglomerated latex was measured by a centrifugal sedimentation type particle size distribution analyzer, and the average particle size was 150 microns.

Subsequently, using the coagulated latex, 300 g of water, 300 g of coagulated latex, 300 g of vinyl chloride monomer 300 g, 2% liquid of polyvinyl alcohol, 10 g of aroyl peroxide were added to a 3-liter stainless steel autoclave equipped with a stirrer, and suspension polymerization was carried out at 58 ° C. for 8 hours. After the completion of the polymerization reaction, the dechlorinated vinyl monomer was washed, dehydrated and dried to obtain a polyvinyl chloride resin having an average degree of polymerization of 1050. At this time, the total amount of polyvinyl chloride was 500 g.

Further, almost no sticking to the can wall of the stainless steel autoclave equipped with a stirrer was observed.

The average particle diameter of the obtained polyvinyl chloride is 150 microns and the particle size distribution is shown in Table 6.

Next, a sheet was prepared from this polyvinyl chloride using the conventional method with the following compounding amounts, and F.I. When E was measured, 1 /
It was 100 cm ² . For comparison, a polyvinyl chloride obtained by carrying out suspension polymerization without passing the latex obtained by the fine suspension polymerization of Example 5 was prepared in the same manner as in F. When E was measured, it was 7 pieces / 100 cm ² .

Polyvinyl chloride 100 parts by weight Plasticizer (DOP: di-2-ethylhexyl phthalate) 50 Stabilizer 1 Carbon 0.5 To 100 parts by weight of this polyvinyl chloride, 3 parts by weight of dibutyltin maleate are added and kneaded with a heating roll. , 180 ° C
As a result of testing the thermal stability in a gear oven of No. 1, the polymer obtained in this Example was colored light yellow in 90 minutes, and its coloring degree was slightly inferior to that of the commercially available suspension polymerization method. 40
Compared with commercially available emulsion polymerized polymers which were also colored in minutes, they showed much better thermal stability.

In addition, F. When the gelling time was measured by a Brabender plastograph using the same composition as in the measuring method of E, it was 85 seconds, and the average degree of polymerization of 1050 obtained by the commercially available suspension polymerization method was compared with this. The gel time of the polymer was 150 seconds. The results show that the processability of the polymer obtained according to the present invention is far superior to that of the polymer obtained by the commercially available suspension polymerization method.

Claims (1)

[Claims] 1. A vinyl chloride polymer latex is produced by an emulsion polymerization method or a fine suspension polymerization method, and coarse particles of 60 mesh or more produced as a by-product during the production of the latex are removed. A vinyl chloride characterized by being disrupted by addition to form a coagulated latex, and suspension-polymerizing vinyl chloride or a mixture of vinyl chloride and a vinyl monomer copolymerizable therewith in the presence of the coagulated latex. Method for producing a base resin.