JPH09227607A - Suspension polymerization process for vinyl chloride monomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vinyl chloride resin with a high porosity, a narrow particle size distribution, and an excellent processibility while reducing the deposition of polymer scale on the inner wall of a polymerizer by adding six specific additives to the reaction system of a water-base suspension polymn. of a vinyl chloride monomer. SOLUTION: In the suspension polymn. of a vinyl chloride monomer in a water-base medium in the presence of an oil-sol. polymn. initiator, to the reaction system are added a partially saponified polyvinyl acetate having a degree of saponification of 60-90mol%, at least one cellulose deriv., a higher fatty acid ester of sorbitan having an HLB of 3-10, an anionic emulsifier, an 8-25C higher fatty acid, and a thickener having a Brookfield viscosity of a 0.1-wt.% aq. soln. of 10-200cP.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suspension polymerization of vinyl chloride monomers.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resins have been used in many applications as materials having excellent mechanical strength, weather resistance and chemical resistance. However, the vinyl chloride resin does not have good processability, and further improvement is demanded. Generally, as a measure for evaluating the moldability of vinyl chloride resin, the amount of absorbed plasticizer, the torque by plastomill and the gelation time are measured. Regarding the amount of absorbed plasticizer, the one in which the plasticizer penetrates into the vinyl chloride resin in a short time has the better processing characteristics, and the plastomill has the lower maximum torque and the shorter the gelation time, the better the processing characteristics. There is.

There are several possible factors that impede the processing characteristics. Among them, the major factor is the presence of the skin on the surface of the vinyl chloride resin particles. The skin means a skin layer existing on the surface of the vinyl chloride resin particles, the main component of which is a dispersant used for polymerization (for example, partially saponified polyvinyl acetate, cellulose derivative, etc.) It is considered to be a layer strongly grafted with a vinyl chloride resin.

Originally, the skin is considered to have the role of protecting the surface of the oil droplets in the polymerization system, regulating the splitting and coalescence of the oil droplets, and stabilizing the polymerization system. However, on the other hand, when processing the obtained vinyl chloride resin, it is necessary to crush individual particles to submicron units (primary particles or less), and in that process, a strong skin of the vinyl chloride resin surface Presence is considered to be a major obstacle.

From the above, as the particle structure of the vinyl chloride resin having excellent processing characteristics, it can be mentioned that the skin on the surface is absent or little even if it is present. Furthermore, since liquid stabilizers, plasticizers, etc. taken inside the vinyl chloride resin particles are easily diffused and absorbed, the porosity inside the vinyl chloride resin particles is large. Less scale generation is believed to be an important factor.

Conventionally, various proposals have been made as a method for producing a vinyl chloride resin, which has less skin portions, has porosity and excellent processing characteristics, and produces less polymer scale during production. For example, Japanese Patent Publication No. 36-2244
Japanese Patent Publication No. 5 discloses a suspension polymerization method in which a sorbitan higher fatty acid ester and a polyoxyethylene sorbitan higher fatty acid ester are used in combination. However, this method has a problem in that the obtained vinyl chloride resin has poor porosity, a large amount of skin remains, and a large amount of polymer scale adheres to the inner wall of the polymerization vessel.

In order to solve the above problems, for example, Japanese Patent Publication No. 53-13395 discloses a combination of a lipophilic sorbitan higher fatty acid ester and a hydrophilic polyoxyethylene sorbitan higher fatty acid ester in the presence of an alkaline compound. A method of using a dispersant and adding a water-soluble cellulose derivative when the polymerization conversion rate of vinyl chloride reaches 5 to 40% is disclosed. Further, for example, in Japanese Examined Patent Publication (Kokoku) No. 5-86408, sorbitan higher fatty acid ester is used as a dispersant, polymerization is started under stirring with a Faudler blade, and when the polymerization conversion rate reaches 5 to 40%, the aqueous solution is dissolved. A method of adding a dispersant is disclosed.

However, in the above two polymerization methods,
Certainly, during the polymerization reaction, vinyl chloride resin particles with few skin parts and rich in porosity can be obtained, but the problem of polymer scale adhesion during polymerization remains unsolved, low bulk density and dispersant Since the post-addition is carried out, a large amount of the dispersant remains on the surface of the resin particles, resulting in deterioration of various physical properties. Further, in the manufacturing process, it is necessary to add the dispersant in two steps in order to prevent the adhesion of polymer scale, which causes a problem that the polymerization operation becomes complicated.

Further, for example, Japanese Patent Laid-Open No. 5-295008.
In the publication, as a system utilizing a nonionic surfactant,
There is disclosed a method in which a known suspension dispersant, a low saponification degree partially saponified polyvinyl acetate, and a nonionic surfactant such as monosorbitan laurate are added in a specific ratio to carry out polymerization. However, although there are cases in which skin on the resin surface is certainly reduced by this method, the operation becomes complicated because it is necessary to control the power required for stirring in the initial stage of polymerization, gelation characteristics, plasticizer absorbability, etc. In terms of processing characteristics, the effect was not yet sufficient.

On the other hand, when an anionic emulsifier is added to the polymerization of a vinyl chloride resin, it is difficult to control the particle size of the resin, and a large amount of polymer scale adheres to the wall of the polymerization vessel. there were. As described above, at present, in the presence of anionic and nonionic emulsifiers, by adding various components all at once, the porosity is high, the particle size distribution is narrow, and the adhesion of polymer scale to the inner wall of the polymerization vessel is small and the processability is low. Excellent vinyl chloride resin has not been obtained.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a polymer scale on the inner wall of a polymerization vessel even if various components are added all at once in the manufacturing process. It is intended to provide a suspension polymerization method for vinyl chloride-based monomers in which the vinyl chloride resin particles obtained have less porosity, are rich in porosity, have a narrow particle size distribution, and have excellent processing characteristics.

[0012]

Means for Solving the Problems The suspension polymerization method of a vinyl chloride monomer according to the present invention is carried out by suspension polymerization of a vinyl chloride monomer in an aqueous medium in the presence of an oil-soluble polymerization initiator. At least one of partially saponified polyvinyl acetate (a) and cellulose derivative (b), sorbitan higher fatty acid ester (c), anionic emulsifier (d), higher fatty acid (e) and thickener ( f) is added and suspension polymerization is performed.

Examples of the vinyl chloride-based monomer used in the present invention include vinyl chloride monomers; mixtures of vinyl chloride monomers and monomers other than vinyl chloride. The monomer other than vinyl chloride is a monomer that can be copolymerized with a vinyl chloride monomer, and includes, for example, alkyl vinyl esters such as vinyl acetate; α-monoolefins such as ethylene and propylene; Examples thereof include vinylidene chloride and styrene, but there is no particular limitation as long as they can be copolymerized with a vinyl chloride monomer.

In the production method of the present invention, at least one selected from the above partially saponified polyvinyl acetate (a) and the above cellulose derivative (b) is used as a suspension dispersant, and both are used in combination. May be.

The above partially saponified polyvinyl acetate (a) is
When the saponification degree is low, the oil solubility becomes strong and the dispersion ability is insufficient, so that the resulting resin has many coarse particles, and when the saponification degree becomes high, the protective colloid property becomes strong, so that a strong skin portion is formed on the resin surface, Since the gelling property deteriorates, 60 to 90 mol% is preferable, and 7 is more preferable.
0 to 85 mol%.

When the average degree of polymerization of the partially saponified polyvinyl acetate (a) is low, it tends to be coarse particles or blocks due to lack of dispersion ability, and when the average degree of polymerization is high, the skin layer of the obtained resin particles is thick and the average porosity is high. Since the moldability is insufficient and the moldability is deteriorated, 500 to 3,000 is preferable,
More preferably, it is 700-1,500.

The partially saponified polyvinyl acetate (a) is
They may be used alone or in combination of two or more.

When the amount of the partially saponified vinyl acetate (a) added is small, the oil droplets are unstable and the resin tends to be in a block shape. When the amount is large, the skin portion of the obtained resin surface is thick and the moldability is poor. Therefore, it is preferably 150 to 2,000 ppm with respect to the vinyl chloride monomer.

As the above cellulose derivative (b),
Methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose and the like can be mentioned, and these may be used alone or in combination of two or more kinds.

When the amount of the above cellulose derivative (b) added is small, the oil droplets become unstable and the resin may be in a block shape. When the amount is large, the skin layer on the surface of the obtained resin becomes thick and sometimes fish. Since there are many glass bead-shaped particles called "eyes" and the molding processability deteriorates, it is 50 to 4,000 pp for vinyl chloride type monomers.
m is preferable, and more preferably 80 to 1,500 ppm
It is.

When the HLB value of the sorbitan higher fatty acid ester (c) used in the present invention is low, it shows a strong lipophilicity, so that the dispersibility in an aqueous medium is low and the particle size distribution of the obtained resin is coarse particles. It will be a wide range including
When it becomes higher, it exhibits strong hydrophilicity and the oil droplets during polymerization become unstable, eventually causing aggregation and coalescence of resin particles, and the obtained resin becomes a block-like or aggregate of coarse particles. It is limited to 10 and preferably 4 to 9.

The HLB (hydrophile-lipophile balance) is WCGr
iffin [J. Soc. Cosmetic Chem., Volume 1, page 311, (194
9)] suggests the balance between the hydrophilic group and the hydrophobic group of the nonionic surfactant. The larger this value, the larger the hydrophilicity, and the smaller the value, the larger the hydrophobicity.

As the sorbitan higher fatty acid ester (c) having the above HLB value, sorbitan monolaurate (HLB value 8.6), sorbitan monomyristate, sorbitan monopalmitate (HLB value 5.6), sorbitan monostea Sorbitan saturated higher fatty acid ester such as rate (HLB value 4.7), sorbitan distearate (HLB value 4.4), sorbitan tristearate (HLB value 2.1); unsaturated higher fatty acid ester, and the like. May be used alone or in combination of two or more.

The sorbitan higher fatty acid ester (c)
If the addition amount of the resin particles is small, the skin layer of the resulting resin particles becomes thick and the molding processability is not improved due to lack of porosity, and if the amount is large, the particle size distribution of the obtained resin particles becomes broad and the inner wall of the polymerization vessel is increased. Since the amount of polymer scale attached increases, it is 500 to 8.0 with respect to the vinyl chloride monomer.
00 ppm is preferable, and more preferably 800 to 5,0.
00 ppm.

Examples of the anionic emulsifier (d) used in the present invention include fatty acid salts such as sodium stearate soap; alkyl sulfate ester salts such as sodium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; octylnaphthalene. Alkylnaphthalene sulfonate such as sodium sulfonate; Alkyl sulfosuccinate such as sodium didodecylsulfo succinate, alkyl diphenyl ether disulfonate, alkyl phosphate, polyoxyethylene alkyl sulfate ester salt, naphthalene sulfonic acid formalin condensation Stuff,
Specific polycarboxylic acid type polymer surfactants, polyoxyethylene alkyl phosphates, reactive surfactants, etc. may be mentioned, and these may be used alone or in combination of two or more.

The amount of the anionic emulsifier (d) added is
When the amount is small, the skin portion of the resin is formed thick and the porosity is insufficient (particularly lacking fine pores of 0.1 μm or less), so there is no effect of improving the moldability, and when the amount is large, the particle size distribution of the resin is broadened and polymerization is performed. Since the amount of polymer scale adhering to the inner wall of the container increases, sometimes it becomes a block and the resin cannot be obtained.
To 1,000 ppm is preferable, and more preferably 25 to
It is 750 ppm.

When the number of carbon atoms of the higher fatty acid (e) used in the present invention is small, it has a water-soluble property, so that it is not distributed to the oil layer during the polymerization and does not exert a gelation accelerating effect. Therefore, since the gelation promoting effect is not exhibited at the molding temperature, it is limited to 8 to 25, and preferably 11 to 22.

Examples of the higher fatty acid (e) having 8 to 25 carbon atoms include isostearic acid, stearic acid, and n.
-Heptadecanoic acid, palmitic acid, n-pentadecanoic acid, myristic acid, aragic acid, nonadecanoic acid, n-tridecanoic acid, lauric acid, undecyl acid, etc.,
These may be used alone or in combination of two or more. As the higher fatty acid (e), the effect is not deteriorated due to the degree of unsaturation of the main chain and branching, but it is particularly preferable to use a linear saturated fatty acid.

When the amount of the higher fatty acid (e) added is small, the effect is not obtained, and when it is large, the gelling time is delayed, so that the amount is 300 to 20,0 with respect to the vinyl chloride-based monomer.
00 ppm is preferred.

The thickener (f) used in the present invention is used for imparting a thickening effect to the reaction system,
When the viscosity of the aqueous solution becomes low, the particle size distribution becomes rough because the thickening effect is not sufficiently exerted during the reaction, and when it becomes high, the aggregation state in the polymerization system changes, and the number of coarse particles of 500 μm or more increases. The Brookfield viscosity (hereinafter referred to as “η”) of a wt% aqueous solution at room temperature under normal pressure is
Limited to 10-200 cps.

The above η is 10 cps (1
Examples of the thickener (f) having a viscosity of 0 mPa · s) or more include polyethylene oxide (η = 12 cps, average molecular weight of preferably 1.7 million to 5.5 million, more preferably 4.3 million to 4.8 million), polyvinylpyrrolidone, poly Other than acrylamide (in all cases, η = 51 cps, average molecular weight is preferably 8,000,000 to 14,000,000, more preferably 12,000,000 to 14,000,000), polyacrylamide copolymer, crosslinked (meth) acrylic acid Polymers, methyl cellulose calcium, sodium starch glycolate, sodium starch phosphate ester, sodium alginate, propylene glycol alginate, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, and the like. These may be used alone, and two or more kinds may be used. The above may be used in combination.

When the amount of the above-mentioned thickening agent (f) added is small, a sufficient thickening effect is not exhibited in the reaction system, so that the particle size distribution of the resin becomes coarse, and when it is large, the resin surface is covered with a strong skin layer. Since the gelation rate becomes slow, it is preferably from 5 to 2,000 ppm, more preferably from 25 to 900 ppm, based on the vinyl chloride monomer.

The polymerization initiator used in the present invention includes
Known oil-soluble polymerization initiators generally used for the polymerization of vinyl chloride resins can be used, for example, organic peroxides such as benzoyl peroxide, lauroyl peroxide, 2-ethylhexyl peroxydicarbonate; azo. Examples thereof include azo compounds such as bisisobutyronitrile and azobisisovaleronitrile, and these may be used alone or in combination of two or more kinds.
Of these, the use of organic peroxides is particularly preferable.

The structure of the polymerization vessel (pressure autoclave) used in the suspension polymerization method of the present invention is not particularly limited, and a known structure conventionally used for polymerization of vinyl chloride can be used. Further, the stirring blade may be a general-purpose one such as a faudler blade, a paddle blade, a turbine blade, a fan turbine blade, or a bull margin blade, and the combination with a baffle plate is not particularly limited.

At the time of the above-mentioned polymerization reaction, the method of charging the reaction system with ion-exchanged water, vinyl chloride monomer, and optionally vinyl monomer other than vinyl chloride is the same as the conventional method. You can do this. Also, depending on the polymerization conditions,
A polymerization modifier, a chain transfer agent, an antistatic agent, a cross-linking agent, a stabilizer, a filler, an anti-scale agent, etc. may be added.

[0036]

Embodiments of the present invention will be described below. (Example 1) 50 kg of deionized water was placed in a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liter, and partially saponified polyvinyl acetate (saponification degree: 72 mol%, average polymerization) with respect to vinyl chloride monomer. 700) 500ppm,
Sorbitan monolaurate (HLB = 8.6) 1500
ppm, polyoxyethylene alkyl ether sulfate ester salt 100 ppm, lauric acid 1500 ppm, polyacrylamide (average molecular weight = 12,000,000 to 1400)
Η = 51 cps) 150 ppm and t-butyl peroxyneodecanoate 500 ppm.
Next, after degassing the inside of the polymerization vessel to 40 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started. Then, the temperature inside the polymerization vessel was raised to 57 ° C. to start the polymerization, and this temperature was maintained until the completion of the polymerization reaction. The reaction was terminated when the conversion of polymerization reached 90%, the unreacted monomer in the polymerization vessel was recovered, the polymer was taken out as a slurry, and dehydrated and dried to obtain a vinyl chloride resin.

Example 2 50 kg of deionized water was placed in a polymerization vessel (pressure autoclave) having an internal volume of 100 liters, and partially saponified polyvinyl acetate (saponification degree: 72 mol%) with respect to vinyl chloride monomer. , Average degree of polymerization 700)
500 ppm, sorbitan monostearate (HLB =
4.7) 1500 ppm, polyoxyethylene alkyl ether sulfate ester salt 100 ppm, stearic acid 1
500 ppm, polyethylene oxide (average molecular weight =
4.3 to 4.8 million, η = 12 cps) 150 ppm and t-butyl peroxy neodecanoate 500 p
pm was added. Next, after degassing the inside of the polymerization vessel to 40 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started. Thereafter, polymerization was carried out in the same manner as in Example 1 to obtain a vinyl chloride resin.

Example 3 Partially saponified polyvinyl acetate having a degree of saponification of 80 mol% and an average degree of polymerization of 1000 was used, and polyoxyethylene alkyl ether phosphate ester was used in place of polyoxyethylene alkyl ether sulfate ester salt. Polymerization was performed in the same manner as in Example 1 except that the above was performed to obtain a vinyl chloride resin.

Example 4 50 kg of deionized water was placed in a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and partially saponified polyvinyl acetate (saponification degree: 72 mol%) with respect to vinyl chloride monomer. , Average degree of polymerization 700)
350ppm, hydroxypropyl methylcellulose 1
50 ppm, sorbitan monolaurate (HLB = 8.
6) 1500 ppm, polyoxyethylene alkyl ether sulfate ester salt 100 ppm, lauric acid 1500
ppm, polyacrylamide (average molecular weight = 12 to 14 million, η = 51 cps) 150 ppm, and t-butyl peroxy neodecanoate 500 ppm were added. Next, after degassing the inside of the polymerization vessel to 40 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started. Thereafter, polymerization was carried out in the same manner as in Example 1 to obtain a vinyl chloride resin.

(Comparative Examples 1 to 3) Except that the partially saponified polyvinyl acetate, sorbitan higher fatty acid ester, anionic emulsifier, higher fatty acid and water-soluble thickener having the properties shown in Table 2 were used. Polymerization was performed in the same manner as in 1 to obtain a vinyl chloride resin. The amount of each component added was the same as in Example 1.

(Comparative Example 4) 50 kg of deionized water was placed in a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and partially saponified polyvinyl acetate (saponification degree: 80 mol%) to vinyl chloride monomer. , Average degree of polymerization 100
0) 500 ppm and t-butyl peroxy neodecanoate 500 ppm were added. Next, after degassing the inside of the polymerization vessel to 40 mmHg, vinyl chloride monomer 33
Stirring was begun by charging kg. Thereafter, polymerization was carried out in the same manner as in Example 1 to obtain a vinyl chloride resin.

Comparative Example 5 50 kg of deionized water was placed in a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and partially saponified polyvinyl acetate (saponification degree: 55 mol%) with respect to vinyl chloride monomer. , Average degree of polymerization 300)
500 ppm, sorbitan monolaurate (HLB =
8.6) 1500 ppm, polyoxyethylene alkyl ether sulfate ester salt 100 ppm, lauric acid 15
00ppm, polyacrylamide (average molecular weight = 120
0,000-14 million, η = 51 cps) 150 ppm and t-butyl peroxy neodecanoate 500 pp
m was thrown in. Next, after degassing the inside of the polymerization vessel to 40 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started. Thereafter, polymerization was carried out in the same manner as in Example 1, and the reaction was terminated when the conversion reached 90%, but the resin became a block-like substance and no granular substance was obtained.

In any of the above examples, no adhesion of polymer scale to the inner wall of the polymerization vessel was observed.

The following performance evaluations were performed on the vinyl chloride resins obtained in the above Examples and Comparative Examples, and the results are shown in Table 1.
And 2. (1) Porosity Using plasticizer absorbency as an index of porosity, 5 g of vinyl chloride resin is weighed into a centrifuge tube with a glass filter (grain roughness: G2), and an excessive amount of DOP (dioctyl phthalate) with respect to the resin is measured. About 20 cc of plasticizer was added and mixed well. Then, excess DOP was separated with a centrifuge (“H-200N” manufactured by Domestic Centrifuge Co., Ltd., rotation speed: 6000 rpm), and the DOP absorption amount (phr) with respect to 100 parts by weight of the resin was determined.

(2) Particle size distribution: 60, 100 and 15 according to JIS Z8801.
The amount of passage (% by weight) was calculated by sieving using three kinds of sieves of 0 mesh. It was determined that the one in which the weight% was concentrated in one mesh had a sharp particle size distribution, and the one in which the weight% was dispersed in each mesh had a poor particle size distribution.

(3) Processability Using "Hake Leo Cord 90" manufactured by Toyo Seiki Co., Ltd., the vinyl chloride resin composition was subjected to gelation time (min) and maximum torque (mk) during gelation under the following conditions.
g · min) was measured. After 60 g of the above resin composition was charged into Haake Leo Cord 90, the temperature was raised from the charging temperature of 120 ° C. at a rotation speed of 50 rpm at a rate of 5 ° C./min to 200 ° C.
Was measured up to. As the vinyl chloride resin composition, as a lubricant, montanic acid ester (“WAX O manufactured by Hoechst Co., Ltd.) was added to 100 parts by weight of the vinyl chloride resin.
P ”) 0.5 part by weight and 2 parts by weight of dibutyltin mercapto (“ JF-10B ”manufactured by Sankyo Machine Gosei Co., Ltd.) as a stabilizer, and heated to 120 ° C. with a super mixer (Mitsui Miike Co., Ltd.) and mixed. Then, the product cooled to 40 ° C. was used.

(4) Surface condition Vinyl chloride resin particles were photographed with a scanning electron microscope ("FE-SEM S-4200" manufactured by Hitachi, Ltd.), and the contours of the particles, the skin portion (the portion where the skin remains), The portion without skin (the portion where the primary particles are exposed) was transferred onto tracing paper (or OHP sheet). Next, a tracing paper (or OHP sheet) was taken into the screen by using an image analysis device ("PIAS-III" manufactured by Pierce), and the total area of the particles and the remaining area of the skin part were calculated by the following formula, The remaining skin rate was used. In the table,
The average value of the measured values of 50 particles is shown. Remaining skin rate (%) = (Area of skin remaining part /
(Total area of particles) × 100 The conditions for using the scanning electron microscope are: acceleration voltage 2 kv,
The magnification was 130 times.

[0048]

[Table 1]

[0049]

[Table 2]

Example 5 50 kg of deionized water was placed in a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and 400 ppm of hydroxypropylmethyl cellulose and sorbitan monolaurate (HLB = 8) were added to vinyl chloride monomer. .6) 1700 ppm, polyoxyethylene alkyl ether sulfate ester salt 100 pp
m, lauric acid 1500 ppm, polyacrylamide (average molecular weight = 12 to 14 million, η = 51 cp
s) 150 ppm and t-butylperoxy neodecanoate 500 ppm were added. Next, after degassing the inside of the polymerization vessel to 40 mmHg, vinyl chloride monomer 33
Stirring was begun by charging kg. Thereafter, polymerization was carried out in the same manner as in Example 1 to obtain a vinyl chloride resin.

Example 6 50 kg of deionized water was placed in a polymerization vessel (pressure autoclave) having an internal volume of 100 liters, and 400 ppm of hydroxypropylmethyl cellulose and sorbitan monostearate (HLB = 4) were added to the vinyl chloride monomer. .7) 1700 ppm, polyoxyethylene alkyl ether phosphate ester 100 pp
m, stearic acid 1500 ppm, polyethylene oxide (average molecular weight = 4.3 million to 4.8 million, η = 12 cp
s) 150 ppm and t-butylperoxy neodecanoate 500 ppm were added. Next, after degassing the inside of the polymerization vessel to 40 mmHg, vinyl chloride monomer 33
Stirring was begun by charging kg. Thereafter, polymerization was carried out in the same manner as in Example 1 to obtain a vinyl chloride resin.

Example 7 The same as Example 1 except that methylpropylcellulose was used instead of hydroxypropylmethylcellulose, and polyoxyethylene alkyl ether phosphate ester was used instead of polyoxyethylene alkyl ether sulfate ester salt. Polymerization was performed to obtain a vinyl chloride resin. The amount of each component added was the same as in Example 1.
Same as.

(Comparative Examples 6 to 8) Except that the partially saponified polyvinyl acetate, sorbitan higher fatty acid ester, anionic emulsifier, higher fatty acid and water-soluble thickener having the properties shown in Table 3 were used. Polymerization was performed in the same manner as in 1 to obtain a vinyl chloride resin. The amount of each component added was the same as in Example 1.

(Comparative Example 9) 50 kg of deionized water was placed in a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and further 400 ppm of methyl cellulose and 500 ppm of t-butyl peroxyneodecanoate were added to the vinyl chloride monomer. Was thrown in. Next, after degassing the inside of the polymerization vessel to 40 mmHg, vinyl chloride monomer 33k
g was charged and stirring was started. Thereafter, polymerization was carried out in the same manner as in Example 1 to obtain a vinyl chloride resin.

(Comparative Example 10) 50 kg of deionized water was placed in a polymerization vessel (pressure resistant autoclave) having an internal volume of 100 liters, and sorbitan monolaurate (1700 ppm) and polyoxyethylene alkyl ether sulfate were added to vinyl chloride monomer. 100 ppm salt, 1 lauric acid
500ppm, polyacrylamide (average molecular weight = 12
5 to 14 million, η = 51 cps) 150 ppm and t-butyl peroxy neodecanoate 500 p
pm was added. Next, after degassing the inside of the polymerization vessel to 40 mmHg, 33 kg of vinyl chloride monomer was charged and stirring was started. Thereafter, polymerization was carried out in the same manner as in Example 1, and the reaction was terminated when the conversion reached 90%, but the resin became black and no particulate matter was obtained.

The vinyl chloride resins obtained in Examples 5 to 7 and Comparative Examples 6 to 10 were subjected to the same performance evaluations (1) to (4) as in Example 1 and the results are shown in Table 3. And 4 are shown.

[0057]

[Table 3]

[0058]

[Table 4]

The following components were used in Tables 1 to 4. (Partially Saponified Polyvinyl Acetate) PVA: Partially Saponified Polyvinyl Acetate (Cellulose Derivative) HMC: Hydroxypropyl Methyl Cellulose MC: Methyl Cellulose (Anionic Emulsifier) A: Polyoxyethylene Alkyl Ether Sulfate Ester Salt (No. "Hitenol N-08" manufactured by Ichigo Kogyo Co., Ltd.) B: Polyoxyethylene alkyl ether phosphate ("Prysurf A212C" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (Sorbitan higher fatty acid ester) SML: Sorbitan monolaurate SMS: Sorbitan monostearate-STS: Sorbitan tristearate (higher fatty acid) -C12: lauric acid-C18: stearic acid-C3: propionic acid (thickener) -PEO: Polyethylene oxide-PAA : Polyac Ruamido

[0060]

The constitution of the suspension polymerization method for vinyl chloride-based monomers of the present invention is as described above, and even if various components are added all at once in the manufacturing process, the adhesion of polymer scale to the inner wall of the polymerization vessel is achieved. The resulting vinyl chloride resin has high porosity, a narrow particle size distribution, and excellent processability.

Claims (1)

[Claims] 1. A reaction system for suspension polymerization of a vinyl chloride monomer in an aqueous medium in the presence of an oil-soluble polymerization initiator,
(A) at least one kind of partially saponified polyvinyl acetate having a saponification degree of 60 to 90 mol% and (b) a cellulose derivative, (c) a sorbitan higher fatty acid ester having an HLB value of 3 to 10, (d) ) Anionic emulsifier, (e)
Brookfield viscosity of higher fatty acid having 8 to 25 carbon atoms and (f) 0.1 wt% aqueous solution is 10 to 200 cp
A suspension polymerization method of a vinyl chloride-based monomer, which comprises adding a thickening agent of s to carry out suspension polymerization.