JP2006322013A - Method for producing chlorinated vinyl chloride resin - Google Patents

Abstract

Provided is a method for producing CPVC that is industrially advantageous while being excellent in gelling performance and heat resistance without generating a large amount of scale during polymerization of PVC.
When a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and another monomer copolymerizable therewith is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator. In addition, a partially saponified polyvinyl acetate (a), a sorbitan fatty acid ester (c) and a higher fatty acid (d) are added to the reaction system and polymerized to chlorinate the vinyl chloride polymer.
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Description

The present invention relates to a method for producing a chlorinated vinyl chloride resin.

Conventionally, a chlorinated vinyl chloride resin (hereinafter referred to as CPVC) is produced by chlorinating a vinyl chloride resin (hereinafter referred to as PVC). Conventionally, PVC has been used in many applications as a material having excellent mechanical strength, weather resistance, and chemical resistance.
However, since PVC has the disadvantage of being inferior in heat resistance, CPVC has been developed in which PVC is chlorinated to improve heat resistance.
Since PVC has a low heat distortion temperature and a usable upper limit temperature is around 60 to 70 ° C., it cannot be used for hot water, whereas CPVC has a heat deformation temperature that is 20 to 40 ° C. higher than PVC. It can be used for water, and is suitably used for, for example, heat resistant pipes, heat resistant joints, heat resistant valves and the like.

However, since CPVC has a high heat distortion temperature, it requires a high temperature and a high shearing force to be gelled during the molding process, and tends to be decomposed and easily colored.
Therefore, CPVC has a narrow molding processing width and is often commercialized in an insufficient gelled state, and it cannot be said that the performance of the material is fully utilized.

In order to solve such problems, for example, in JP-A-49-6080, by using a suspension stabilizer composed of an ionic emulsifier, a water-soluble metal salt and a water-soluble polymer dispersant, A method for chlorinating PVC composed of agglomerates of about 1 μm elementary particles is disclosed.
However, in this method, although the gelation performance at the time of molding is improved, it is not yet sufficient, and a large amount of scale is generated during the polymerization, which adheres to the wall surface of the polymerization tank and inhibits the heat removal effect. There was a problem that the scale removal work was required.

Further, for example, in JP-A-61-174201, after PVC is polymerized in the presence of a cellulose-based dispersant, the PVC after the cellulose-based dispersant film is removed by the action of a cellulose-degrading enzyme is post-chlorinated. A method is disclosed.
However, in this method, cellulose is fused closely with the vinyl chloride polymer as an outer shell on the PVC surface, and even if cellulose degrading enzyme is acted on, the effect is not sufficiently exhibited. There was a problem that performance and plasticizer absorbability were not improved.
JP 49-6080 A JP-A-61-174201

The present invention has been made in order to solve the above-mentioned problems. The object of the present invention is to produce a large amount of scale at the time of polymerization of PVC, excellent gelation performance and heat resistance, and industrially advantageous CPVC. It is in providing the manufacturing method of.

The method for producing a chlorinated vinyl chloride resin according to the invention described in claim 1 (hereinafter referred to as the present invention) comprises a vinyl chloride monomer alone or a vinyl chloride monomer and another monomer copolymerizable therewith. When the mixture is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator, (a) the addition amount to the vinyl chloride monomer is 150 to 500 ppm, and the average saponification degree is 60 to 90 mol% partially saponified polyvinyl acetate, (c) a sorbitan fatty acid ester having an HLB of 3 to 10 and an addition amount to the vinyl chloride monomer of 1500 to 8000 ppm, and (d) a higher fatty acid having 8 to 25 carbon atoms And (e) a vinyl chloride polymer obtained by polymerization by adding a thickening additive having a viscosity of 10 to 200 cps in a 0.1 wt% aqueous solution is chlorinated.

  Other monomers copolymerizable with the vinyl chloride monomer used in the present invention include alkyl vinyl esters such as vinyl acetate; α-monoolefins such as ethylene and propylene, vinylidene chloride, styrene and the like However, there is no particular limitation as long as it is copolymerizable with the vinyl chloride monomer.

  The partially saponified polyvinyl acetate (a) is used as a suspending dispersant, and the average saponification degree is low, the oil solubility becomes strong and the dispersion ability is insufficient. When it becomes higher, the protective colloid property becomes stronger, so that a thick skin layer is formed on the surface of the obtained PVC particles, and later chlorination suitability is deteriorated. Therefore, 60 to 90 mol% is preferable, more preferably 70 to 85 mol%. .

  When the average degree of polymerization of the partially saponified polyvinyl acetate (a) is low, the dispersion ability is insufficient, so that PVC tends to be coarse particles or blocks, and when it is high, the skin layer of the PVC particles becomes thick and porous (fine Since the pore area) is insufficient and the suitability for chlorination afterwards becomes worse, 500 to 3,000 is preferable, and 700 to 1,500 is more preferable.

  When the amount of the partially saponified polyvinyl acetate (a) is decreased, the oil droplets are unstable, so that the PVC tends to be in a block shape. Since it worsens, 150-2,000 ppm is preferable with respect to a vinyl chloride monomer.

  The cellulose derivative (b) used in the present invention is used as a suspension dispersant, and examples thereof include methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose and the like, and these may be used alone. Two or more kinds may be used in combination.

  When the amount of the cellulose derivative (b) added is small, the oil droplets become unstable and PVC particles may not be obtained, resulting in a block shape. When the amount is increased, the skin layer on the surface of the PVC particles becomes thick, sometimes glass beads. 150-2,000 ppm with respect to the vinyl chloride monomer is preferable because the number of particles increases and the chlorination suitability decreases.

The HLB value of the sorbitan fatty acid ester (c) used in the present invention is limited to 3 to 10, preferably 4 to 9.
When the HLB value is less than 3, the dispersion capacity in an aqueous medium is low due to strong lipophilicity, and the particle size distribution of the obtained PVC is in a wide range including coarse particles.
On the other hand, if the HLB value exceeds 10, the oil droplets during polymerization are strong and the oil droplets during polymerization become unstable, and eventually aggregation and coalescence of particles occur, so that it becomes easy to form aggregates of block-like resins or coarse particles.

  Examples of the sorbitan fatty acid ester (c) include sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan saturated higher fatty acid ester such as sorbitan tristearate, Saturated higher fatty acid ester is mentioned, These may be used independently and 2 or more types may be used together.

  When the amount of the sorbitan fatty acid ester (c) is reduced, the skin layer is formed thicker and the porosity is insufficient and the chlorination suitability is lowered. Since the amount increases, it is preferably 800 to 8,000 ppm with respect to the vinyl chloride monomer.

  The higher fatty acid (d) used in the present invention is limited to 8 to 25 carbon atoms, preferably 11 to 22 carbon atoms. If the number of carbon atoms is less than 8, it has water-soluble properties, so that it is not distributed to the oil layer during the polymerization, and the proportion of fine pores decreases. Moreover, when carbon number exceeds 25, in the case of chlorination, a fatty-acid main chain will be parted and chlorinated, and it may have a bad influence on the thermal stability of CPVC obtained.

  The amount of the higher fatty acid (d) added is not effective when it is reduced, and the heat stability of CPVC after chlorination is deteriorated when it is increased, so that it is preferably 300 to 20,000 ppm relative to the vinyl chloride monomer.

  Examples of the higher fatty acid (d) include isostearic acid, stearic acid, n-heptadecanoic acid, palmitic acid, n-pentadecanoic acid, myristic acid, alginate, nonadecanoic acid, n-tridecanoic acid, lauric acid, undecylic acid, and the like. These may be used alone or in combination of two or more.

  The higher fatty acid (d) is preferably a straight-chain saturated fatty acid because the thermal stability of CPVC after chlorination may be slightly deteriorated due to the degree of unsaturation of the main chain and branching.

  The thickening additive (e) used in the present invention has a thickening effect and has a Brookfields viscosity of 10 to 200 cps (mPa · s) of a 0.1 wt% aqueous solution at room temperature and normal pressure. And preferably 11 to 140 cps (mPa · s).

The Brookfields viscosity is 100 cc of a thickening additive aqueous solution adjusted to a 0.1% by weight aqueous solution, left in a thermostatic bath at 25 ° C. for 2 hours, and then the viscometer rotor (NO. 2) is kept at a certain level of the aqueous solution. Soaked and rotated at 60 rpm.
The numerical value was read when the scale of the viscometer was stabilized, and the value converted to 5 times was taken as the viscosity [cps (mPa · s)] of the solution.

  If the Brookfields viscosity of the 0.1% by weight aqueous solution of the thickening additive (e) is less than 10 cps (mPa · s), the thickening effect is not exhibited and the particle size distribution is deteriorated. The chlorination degree is not uniform. On the other hand, if it exceeds 200 cps (mPa · s), the average molecular weight of the additive is increased and the dispersion in water is deteriorated, so the effect of improving the particle size distribution is reduced, and the chlorination suitability is lowered.

  Examples of the thickening additive (e) include polyethylene oxide (weight average molecular weight 1.7 million to 5.5 million, preferably 4.3 million to 4,800,000, viscosity of 0.1 wt% aqueous solution 12 cps), polyvinylpyrrolidone, polyacrylamide ( Weight average molecular weight 8 million to 14 million, preferably 12 million to 14 million, 0.1 wt% aqueous solution viscosity 51 cps), polyacrylamide copolymer, cross-linked (meth) acrylic acid polymer, methylcellulose calcium, starch glycol Examples thereof include sodium acid, sodium starch phosphate, sodium alginate, propylene glycol alginate, carboxymethyl cellulose sodium, carboxymethyl cellulose calcium and the like. These may be used alone or in combination of two or more.

  If the amount of the thickening additive (e) is decreased, the effect of improving the particle size distribution is lowered because the thickening effect is not sufficiently exhibited in the reaction system, and if the amount is increased, the surface of the PVC particles is covered with a strong skin layer. Therefore, the chlorination suitability is lowered, so 5 to 2,000 ppm is preferable with respect to the vinyl chloride monomer, and more preferably 25 to 1,700 ppm.

  As the oil-soluble polymerization initiator used in the present invention, known ones generally used for polymerization of vinyl chloride resins can be used, such as t-butylperoxyneodecanoate, t-hexylperper. Oxyneodecanoate, t-hexylperoxypivalate, α-cumylperoxyneodecanoate, t-hexylneohexanoate, 2,4,4-trimethylpentyl-2-peroxy-2-neodecanoate, etc. Perester compounds; percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate; decanoyl peroxide, lauroyl per Oxide, benzoyl Peroxide compounds such as peroxide, cumene hydroperoxide, cyclohexanone peroxide, 2,4-dichlorobenzoyl peroxide, p-methane hydroperoxide, 3,5,5-trimethylhexanoyl peroxide, isobutyryl peroxide; α, azo compounds such as α'-azobisisobutyronitrile, α, α'-azobis (2,4-dimethylvaleronitrile), α, α'-azobis (4-methoxy-2,4-dimethylvaleronitrile), etc. These may be used alone or in combination of two or more.

The shape and structure of the polymerization vessel (pressure-resistant autoclave) used in the present invention are not particularly limited, and those conventionally used for polymerization of PVC are used.
The agitating blade may be a commonly used blade such as a Faudler blade, a paddle blade, a turbine blade, a fan turbine blade, or a bull margin blade. In particular, a Faudler blade is preferable and combined with a baffle There is no particular restriction.

In the present invention, the PVC obtained by the conventional method is post-chlorinated.
In the chlorination step, a conventional chlorination method can be used as it is. For example, it can be performed in a state where PVC is suspended, dissolved in a solvent, or in a solid state. This is done by contacting them.

  Among the above methods, in particular, when chlorinating in a suspended state, the PVC obtained by the suspended state is directly separated into the suspension itself obtained by suspension polymerization without separating it from the aqueous medium. It can also be chlorinated by blowing.

  In the case of chlorination in the suspended state, the reaction product can be irradiated with a light source to promote chlorination photoreactively. As the light source, ultraviolet rays; visible rays such as mercury lamps, arc lamps, incandescent bulbs, fluorescent lamps, and carbon arc lamps are preferably used, and ultraviolet rays are particularly effective.

  In addition, a small amount of ketones such as acetone and methyl ethyl ketone may be added to the aqueous medium, and a small amount of chlorinated solvent such as hydrochloric acid, trichloroethylene, and carbon tetrachloride may be added as necessary. .

  It is preferable to adjust so that the chlorine content rate of CPVC obtained may be 60 to 70% by weight in the chlorination step.

  The method for producing a chlorinated vinyl chloride resin of the present invention has the above-described configuration, and a PVC with a small skin on the particle surface and a very high proportion of fine pores inside the particle is obtained by suspension polymerization. When this PVC is chlorinated, it is considered that uniform chlorination proceeds rapidly to the inside of the PVC particles. Therefore, the obtained CPVC has high heat resistance and excellent gelation performance during molding.

Examples of the present invention will be described below.
Example 1
[Preparation of PVC]
In a 100 liter polymerization vessel (pressure autoclave), 50 kg of deionized water, 500 ppm of partially saponified polyvinyl acetate having the average saponification degree and average polymerization degree shown in Table 1, and sorbitan mono Laurate (HLB8.6) 1,500 ppm, lauric acid 1,400 ppm and t-butylperoxyneodecanoate 500 ppm were added. Next, after the inside of the polymerization vessel was deaerated to 45 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started.
Polymerization was started by raising the temperature in the polymerization vessel to 57 ° C., and this temperature was maintained until the polymerization reaction was completed. The reaction was terminated when the polymerization conversion rate reached 90%, and the unreacted monomer in the polymerization vessel was recovered. Then, the polymer was taken out of the system in a slurry state and dehydrated and dried to obtain PVC.

[Preparation of CPVC]
A glass-lined reaction tank having an internal volume of 300 liters was charged with 150 kg of deionized water and 45 kg of PVC obtained above, and stirred to disperse the PVC in water. Thereafter, the temperature of the reaction tank was raised and the inside of the tank was kept at 70 ° C. . Next, after nitrogen gas was blown into the reaction tank and the inside of the tank was replaced with nitrogen gas, chlorine gas was blown into the reaction tank, and PVC was chlorinated while irradiating the inside of the tank with ultraviolet rays with a mercury lamp.
The chlorination reaction is continued while measuring the concentration of hydrochloric acid in the tank and examining the progress of the chlorination reaction. When the chlorine content of the produced CPVC reaches 66.5% by weight, the supply of chlorine gas is stopped. The chlorination reaction was completed.
Further, nitrogen gas was blown into the tank to remove unreacted chlorine, and the obtained dispersion was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain powdery CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Example 2)
Instead of sorbitan monolaurate, PVC was obtained in the same manner as in Example 1 except that 1,500 ppm of sorbitan monostearate (HLB4.7) was used. Chlorination gave CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Example 3)
A PVC was obtained in the same manner as in Example 1 except that partially saponified polyvinyl acetate having an average saponification degree of 80 mol% and an average polymerization degree of 1,000 was used. To obtain CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Comparative Examples 1-3)
After obtaining PVC in the same manner as in Example 1 except that partially saponified polyvinyl acetate, sorbitan fatty acid ester and higher fatty acid having average saponification degree and average polymerization degree shown in Table 2 were used, this PVC was obtained. Was chlorinated in the same manner as in Example 1 to obtain CPVC.

(Comparative Example 4)
PVC was obtained in the same manner as in Example 1 except that partially saponified polyvinyl acetate, sorbitan fatty acid ester and higher fatty acid having the average saponification degree and average polymerization degree shown in Table 2 were used. Since the PVC particles were coarse particles having a particle size of about 1,000 μm, they were not chlorinated.

(Comparative Example 5)
The PVC was treated in the same manner as in Example 1 except that partially saponified polyvinyl acetate having an average saponification degree and an average polymerization degree shown in Table 2 was used and no sorbitan fatty acid ester and higher fatty acid were used. After being obtained, this PVC was chlorinated in the same manner as in Example 1 to obtain CPVC.

The following performance evaluation was performed on the CPVC obtained in the above Examples and Comparative Examples (excluding Comparative Example 5), and the results are shown in Tables 1 and 2.
(1) Measurement of gelation temperature Using “Rheocord 90” manufactured by Haak, the following resin composition 55 g was kneaded while increasing the temperature from 150 ° C. at a temperature increase rate of 5 ° C. at a rotation speed of 40 rpm. The temperature and torque when the kneading torque was maximized were measured.
In addition, as a resin composition, what consists of 3 weight part of tribasic lead sulfate, 1 weight part of dibasic lead stearate, and 10 weight part of MBS resin with respect to 100 weight part of CPVC was used.

(2) Thermal stability test The above-mentioned resin composition was supplied to a kneader composed of two 8-inch rolls and kneaded at a roll surface temperature of 205 ° C. The CPVC was wound every 30 seconds after the kneaded material was wound around the roll. While cutting back the sheet, a small amount of sheet was cut out every 3 minutes, the degree of coloring of the sheet was compared, and the thermal stability was determined by the time to turn blackish brown.

(3) Vicat softening temperature The 5-mm-thick CPVC sheet produced in the above thermal stability test was cut into a 15-mm square and used as a measurement sample. Then, it was measured according to JIS K7206 (weight 1.0 kgf).

Example 4
After obtaining PVC in the same manner as in Example 1 except that 800 ppm of hydroxypropyl methylcellulose was used instead of partially saponified polyvinyl acetate and 2,500 ppm of sorbitan monolaurate was used instead of sorbitan monostearate, respectively. This PVC was chlorinated in the same manner as in Example 1 to obtain CPVC.
The CPVC of the obtained CPVC was 66.5% by weight.

(Example 5)
After obtaining PVC in the same manner as in Example 4 except that 2,500 ppm of sorbitan monostearate was used instead of sorbitan monolaurate, this PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. It was. The CPVC of the obtained CPVC was 66.5% by weight.

(Example 6)
A PVC was obtained in the same manner as in Example 4 except that 800 ppm of methyl cellulose instead of hydroxypropyl methylcellulose and 1,800 ppm of stearic acid instead of lauric acid were used. To obtain CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Comparative Examples 6-8)
Except for using the cellulose derivative, sorbitan fatty acid ester and higher fatty acid shown in Table 4, PVC was obtained in the same manner as in Example 4, and then this PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. Obtained.

(Comparative Example 9)
PVC was obtained in the same manner as in Example 4 except that no cellulose derivative was used, but chlorination was not performed because PVC aggregated in a block shape in the polymerization vessel.

(Comparative Example 10)
After obtaining PVC in the same manner as in Example 4 except that sorbitan fatty acid ester and higher fatty acid were not used, this PVC was chlorinated in the same manner as in Example 1 to obtain CPVC.

  The CPVCs obtained in Examples 4 to 6 and Comparative Examples 6 to 10 were measured in the same manner as in Example 1, and the results are shown in Tables 3 and 4.

(Example 7)
[Preparation of PVC and CPVC]
A polymer vessel (pressure-resistant autoclave) having an internal volume of 100 liters, 50 kg of deionized water and vinyl chloride monomer, 500 ppm of partially saponified polyvinyl acetate having an average degree of saponification and an average degree of polymerization shown in Table 5, sorbitan mono Laurate (HLB8.6) 1,500 ppm, Lauric acid 1,400 ppm, Polyethylene oxide (weight average molecular weight: 430 to 4.8 million, 0.1 wt% aqueous solution: 12 cps) 150 ppm and t-butylperoxyneodecanoate 500 ppm Was introduced.
Next, after the inside of the polymerization vessel was deaerated to 45 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started.
The temperature inside the polymerization vessel was raised to 57 ° C. to initiate polymerization, and this temperature was maintained until the polymerization reaction was completed. The reaction was terminated when the polymerization conversion rate reached 90%, and the unreacted monomer in the polymerization vessel was recovered. Then, the polymer was taken out of the system in a slurry state and dehydrated and dried to obtain PVC. This PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Example 8)
PVC was obtained in the same manner as in Example 7 except that 1,500 ppm of sorbitan monostearate was used instead of sorbitan monolaurate, and then this PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. Obtained. The CPVC of the obtained CPVC was 66.5% by weight.

Example 9
500 ppm of partially saponified polyvinyl acetate having an average degree of saponification of 80 mol% and an average degree of polymerization of 1,000, and polyacrylamide as a thickening additive (weight average molecular weight: 12 million to 14 million, 0.1 wt% aqueous solution: 51 cps ) PVC was obtained in the same manner as in Example 7 except that 150 ppm was used, and the PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Comparative Examples 11-13)
PVC was obtained in the same manner as in Example 7 except that partially saponified polyvinyl acetate, sorbitan fatty acid ester, higher fatty acid and thickening additive shown in Table 6 were used. Was chlorinated in the same manner as above to obtain CPVC.

(Comparative Example 14)
PVC was obtained in the same manner as in Example 7 except that partially saponified polyvinyl acetate, sorbitan fatty acid ester, higher fatty acid and thickening additive shown in Table 6 were used. Chlorination was not performed because of coarse particles having a particle size of about 1,000 μm.

  The CPVCs obtained in Examples 7 to 9 and Comparative Examples 11 to 13 were measured in the same manner as in Example 1, and the results are shown in Tables 5 and 6.

(Example 10)
[Preparation of PVC and CPVC]
Polymerizer (withstand pressure autoclave) with an internal volume of 100 liters, deionized water 50 kg, vinyl chloride monomer, hydroxypropyl methylcellulose 800 ppm as cellulose derivative, sorbitan monolaurate (HLB8.6) 2500 ppm, lauric acid 1,800 ppm, polyacrylamide (weight average molecular weight: 12 million to 14 million, 0.1 wt% aqueous solution: 51 cps) 100 ppm and t-butyl peroxyneodecanoate 500 ppm were added.
Next, after the inside of the polymerization vessel was deaerated to 45 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started.
The temperature inside the polymerization vessel was raised to 57 ° C. to initiate polymerization, and this temperature was maintained until the polymerization reaction was completed. The reaction was terminated when the polymerization conversion rate reached 90%, and the unreacted monomer in the polymerization vessel was recovered. Then, the polymer was taken out of the system in a slurry state and dehydrated and dried to obtain PVC. This PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Example 11)
PVC was obtained in the same manner as in Example 10 except that 2,500 ppm of sorbitan monostearate was used instead of sorbitan monolaurate, and this PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. Obtained. The CPVC of the obtained CPVC was 66.5% by weight.

(Example 12)
Except that methylcellulose 800 ppm was used as the cellulose derivative and polyethylene oxide (weight average molecular weight: 4.3 million to 4.8 million, 0.1 wt% aqueous solution: 12 cps) 100 ppm was used as the thickening additive, respectively, in the same manner as in Example 7. After obtaining PVC, this PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. The CPVC of the obtained CPVC was 66.5% by weight.

(Comparative Examples 15-17)
Except for using the cellulose derivative, sorbitan fatty acid ester, higher fatty acid and thickening additive shown in Table 8, PVC was obtained in the same manner as in Example 10, and then this PVC was treated in the same manner as in Example 1. Chlorination gave CPVC.

(Comparative Example 18)
Except for using the cellulose derivatives and higher fatty acids shown in Table 8, PVC was obtained in the same manner as in Example 10, but the obtained PVC particles are coarse particles having a particle diameter of about 1,000 μm. Chlorination was not performed.

  The CPVCs obtained in Examples 10 to 12 and Comparative Examples 15 to 18 were measured in the same manner as in Example 1, and the results are shown in Tables 7 and 8.

Claims (1)

When suspension polymerization of a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and another monomer copolymerizable therewith in an aqueous medium in the presence of an oil-soluble polymerization initiator is carried out. (A) partially saponified polyvinyl acetate having an average saponification degree of 60 to 90 mol%, (c) having an HLB of 3 to 10 and a single vinyl chloride content. A sorbitan fatty acid ester having an addition amount to a monomer of 1500 to 8000 ppm, (d) a higher fatty acid having 8 to 25 carbon atoms, and (e) a thickening additive having a viscosity of 10 to 200 cps in a 0.1 wt% aqueous solution. A method for producing a chlorinated vinyl chloride resin characterized by chlorinating a vinyl chloride polymer obtained by polymerization.