JP2000109506A - Production of vinyl chloride-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject porous polymer excellent in monomer removing properties and further calender molding processability and capable of providing a molded product of good quality by specifying a heat removal ratio of a reflux condenser using a large-sized polymerizer, adding a specific dispersion stabilizer and a specified ammonium salt and carrying out a suspension polymerization of a vinyl chloride-based monomer in the presence of an oil-soluble polymerization initiator in an aqueous medium. SOLUTION: A polymerizer additionally equipped with a stirrer, an external jacket and a reflux condenser and having >=100 m3 internal volume is used and a suspension polymerization of a vinyl chloride-based monomer is carried out in the presence of an oil-soluble polymerization initiator in an aqueous medium under conditions of >=30% amount of heat removal with the above condenser during the polymerization based on the total heat quantity and within 6 h polymerization time by adding a partially saponified polyvinyl alcohol and/or hydroxypropyl methyl cellulose as a dispersion stabilizer and further adding an ammonium salt represented by the formula (Rl to R4 are each a 1-10C alkyl; X is a counterion atom or the like) to produce the objective polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a vinyl chloride polymer. More specifically, high-speed polymerization is performed in a large-sized polymerization vessel with the heat removal rate of the reflux condenser being 30% or more, and it is porous and has excellent demonomerization properties. The present invention relates to a method for producing a vinyl chloride polymer which produces a fisheye and a vinyl chloride polymer having an excellent hue with high productivity.

[0002]

2. Description of the Related Art Vinyl chloride polymers have excellent physical properties,
Due to its mechanical properties, it is used in many fields. As a molding method of this vinyl chloride polymer,
Extrusion molding, calendar molding, injection molding and the like are common. Among these, in calender molding applications, when forming sheets or films, depending on the compatibility of the vinyl chloride polymer and the compounding agent, stickiness with the roll may occur, resulting in uneven thickness or winding around the roll. There were problems such as a decrease in performance. Further, even if the vinyl chloride polymer is less likely to cause roll adhesion, a fisheye or poor color tone which impairs the appearance of the molded product is not suitable for calendar applications. Further, in recent years, there has been a strong demand from processing users for a slightly inexpensive vinyl chloride-based polymer in order to reduce raw material costs, and a technology for producing an inexpensive vinyl chloride-based polymer while maintaining quality has been eagerly desired. For these reasons, calender molding users have demanded the development of a vinyl chloride polymer that is inexpensive, has little roll stickiness, and has good fisheye and hue of the molded product.

On the other hand, in the vinyl chloride polymer manufacturing industry, in order to provide a cheaper vinyl chloride polymer, a conventional low-capacity polymerizer has been changed from a high-capacity polymerizer having a productivity of 100 m ³ or more. Switching is being considered. If the polymerization time is shortened by increasing the amount of initiator to increase production efficiency in such a large-scale polymerization reactor, the cooling capacity cannot catch up with the conventional jacket-type heat removal alone. Is used to remove excess heat of reaction. However, when the heat removal amount of the reflux condenser is increased in order to enhance the production efficiency, a foaming phenomenon in which the polymer particles float as a cream layer on the upper part of the suspension as the polymerization proceeds is observed. In particular, when the polymerization is performed with the heat removal ratio of the reflux condenser being 30% or more, this foaming phenomenon becomes remarkable, a large amount of scale adheres to the inside of the reflux condenser and the conduit, and the heat removal ability of the reflux condenser is reduced. There have been problems such as lowering the quality and deteriorating the fish eye of the molded product in terms of quality.

[0004] In order to avoid the above-mentioned problems, a method is generally adopted in which polymerization is carried out with the heat removal rate of the reflux condenser being less than 30% of the total polymerization heat removal. However, in this method, the heat removal performance of the reflux condenser is taken. However, it is difficult to keep the polymerization time within 6 hours, for example, and there remains a problem in terms of high-speed and high-productivity polymerization. In order to carry out high-speed and high-productivity polymerization, it is necessary to conduct polymerization by using a large-sized polymerization vessel and setting the heat removal ratio of the reflux condenser to at least 30% or more of the total polymerization heat removal amount.

In order to commercialize the vinyl chloride polymer thus polymerized, generally, unreacted vinyl chloride monomer is removed from the slurry containing the vinyl chloride polymer after the polymerization is completed. A method of removing the polymer using a tower or the like, separating the polymer from the aqueous medium using a centrifugal dehydrator or the like, and drying the polymer using a fluidized drier is employed. During this series of operations, unreacted vinyl chloride-based monomers (hereinafter referred to as residual monomers) remaining in the polymer are reduced to a level at which there is no health problem. However, the vinyl chloride polymer having poor porosity has a problem that the residual monomer value increases due to poor monomer removal.

[0006] In order to solve the problem of residual monomers, a method of strengthening the processing conditions of a demonomerization tower or a fluidized dryer or a method of coping with a polymerization recipe has been generally adopted. The former methods include raising the processing temperature and increasing the residence time of the vinyl chloride polymer.However, there are problems such as deterioration of the hue of the obtained vinyl chloride polymer and reduction in production efficiency. there were. For the latter, for example, as a dispersion stabilizer, a water-soluble low polymerization degree, a dispersant formulation based on partially saponified polyvinyl alcohol having a low saponification degree, or an oil-soluble low polymerization degree in this dispersant formulation, Examples include a method of polymerizing with a dispersant formulation using a partially saponified polyvinyl alcohol having a low saponification degree, and the vinyl chloride-based polymer obtained by these methods has a very small internal void of particles (hereinafter referred to as porosity). ) Is large, and the residual monomer can be easily reduced. However, in such a dispersant formulation, the foaming phenomenon during polymerization is remarkable even when the heat removal ratio of the reflux condenser is less than 30%, and the foaming phenomenon is further increased when the heat removal ratio is 30% or more. And, in the worst case, the reflux condenser was clogged and the polymerization had to be stopped halfway. Also in the molding process, the vinyl chloride-based polymer produced by these dispersant methods has a problem that roll adhesion to a calender is remarkable and is unsuitable for calender applications.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to carry out high-speed polymerization in a large-sized polymerization vessel by setting a heat removal rate of a reflux condenser to 30% or more, to be porous and excellent in demonomerization, and to carry out calendering. An object of the present invention is to provide a method for producing a vinyl chloride-based polymer, which can produce a vinyl chloride-based polymer excellent in fisheye and hue of a molded article with high productivity with little occurrence of roll stickiness during processing.

[0008]

Means for Solving the Problems The present inventors have made intensive studies in order to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention is constituted as follows.

Using a polymerization vessel having an internal volume of 100 m ³ or more provided with a stirrer, an outer jacket and a reflux condenser,
Under polymerization conditions in which the amount of heat removed by the reflux condenser during polymerization is 30% or more of the total amount of heat removed and the polymerization time is within 6 hours, the vinyl chloride-based monomer is added in the presence of an oil-soluble polymerization initiator. (A) Degree of saponification: 75 to 90 mol%, average degree of polymerization: 1500
-3000 partially-saponified polyvinyl alcohol in an amount of 0.02-0.15 per 100 parts by weight of the vinyl chloride monomer.
Parts by weight (B) hydroxypropyl methylcellulose and / or saponification wherein the degree of methoxy substitution is 15 to 40% by weight, the degree of hydroxypropoxy substitution is 5 to 25% by weight, and the viscosity of the 2% by weight aqueous solution at 20 ° C. is 10 to 80 cps. Of partially saponified polyvinyl alcohol having a degree of polymerization of 25 to 65 mol% and an average degree of polymerization of 200 to 1000
0.005 to 0.05 parts by weight based on 00 parts by weight, and the total of (A) and (B) is 0.03 to 0.2 parts by weight based on 100 parts by weight of the vinyl chloride monomer, (A) /
The weight ratio of (B) is from 0.5 to 4, and an ammonium salt represented by the following general formula (1) (formula 1) is converted to a vinyl chloride monomer during a polymerization conversion of 10% from the initial stage of polymerization. A method for producing a vinyl chloride polymer, comprising adding 1 × 10 ^{−7 to} 0.01 part by weight per 100 parts by weight.

[0010]

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(R ¹ , R ² , R ³ , and R ⁴ are the same or different linear or branched alkyl groups having 1 to 10 carbon atoms, and X is any counter ion atom or compound.)

A lubricant comprising at least one compound selected from the group consisting of polyolefins, paraffins, and chlorinated hydrocarbons and having an average particle size of 300 μm or less is used in a slurry state at the beginning of polymerization, during polymerization, or after completion of polymerization. 3. The method for producing a vinyl chloride-based polymer composition according to claim 1, wherein 0.001 to 0.3 parts by weight is added to 100 parts by weight of the vinyl chloride-based monomer.

A vinyl chloride-based polymer produced by the method for producing a vinyl chloride-based polymer described in or.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The polymerization vessel used in the present invention has an internal volume of 10 provided with a stirrer, an outer jacket and a reflux condenser.
It is a polymerizer of 0 m ³ or more, preferably 120 m ³ or more, more preferably 150 m ³ or more. In a polymerization vessel having an internal volume of less than 100 m ³ , heat can be removed by a normal external jacket cooling method, and a reflux condenser is not necessarily required. or,
In the case of a polymerization vessel having an internal volume of less than 100 m ^3, the production amount per batch is small, so that it is necessary to have a large number of polymerization vessels in order to increase the production amount. For this reason, there are cost problems such as complicated polymerization equipment and increased capital investment.
In addition, in such a large-capacity polymerization vessel, if the heat removal amount of the reflux condenser is increased, the polymerization time can be remarkably reduced as compared with the conventional jacket-type polymerization vessel, and this has not been possible so far. High-speed and high-productivity polymerization is possible. The heat removal ratio of the reflux condenser is 30% or more, preferably 40% or more, more preferably 50% or more of the total polymerization heat removal amount. If the heat removal ratio is less than 30%, the polymerization time cannot be shortened due to the problem of heat removal, so that the production efficiency is undesirably reduced. If the heat removal ratio of the reflux condenser is less than 30%, the foaming phenomenon does not become a very serious problem, and the present invention is not necessarily required. On the other hand, when the heat removal ratio is 30% or more, the polymerization time can be shortened. In particular, when the heat removal ratio is 40% or more, the polymerization time can be greatly reduced, and the production efficiency can be improved.

The dispersion stabilizer (A) used in the present invention has a saponification degree of 75 to 90 mol%, preferably 75 to 90 mol%.
~ 88 mol%, more preferably 75 ~ 85 mol%, and the average degree of polymerization is 1500 ~ 3000, preferably 170
0 to 3000, more preferably 1700 to 2800, partially saponified polyvinyl alcohol, 0.02 to 0.15 parts by weight based on 100 parts by weight of the vinyl chloride monomer,
Preferably 0.02 to 0.13 parts by weight, more preferably 0.02 to 0.12 parts by weight. Here, when the degree of saponification of the dispersion stabilizer (A) is less than 75 mol% or the average degree of polymerization is less than 1500, the polymerization stability is poor, and the polymerization heat removal ratio of the reflux condenser is 30% or more. In such a case, there is a problem that the foaming phenomenon particularly during the polymerization becomes severe, so that the scale adheres to the reflux condenser. Further, even in the forming process, roll adhesion on a calendar becomes remarkable, which is not preferable. On the other hand, when the degree of saponification is 90 mol% or the average degree of polymerization exceeds 3,000, it is not preferable because there are problems such as a broad particle size distribution of the obtained vinyl chloride-based polymer and deterioration of fish eyes. .
When the amount is less than 0.02 parts by weight, the polymerization stability is poor, and when the amount exceeds 0.15 parts by weight, the obtained vinyl chloride polymer becomes finer and the powder handling becomes difficult. However, the fish eye of the molded product is also deteriorated, which is not preferable.

As the dispersion stabilizer (B) used in the present invention, hydroxypropyl methylcellulose and / or partially saponified polyvinyl alcohol is used. Hydroxypropylmethylcellulose has a degree of methoxy substitution of 15 to 40% by weight, preferably 20 to 35% by weight, more preferably 25 to 30% by weight, and a degree of hydroxypropoxy substitution of 5 to 25% by weight, preferably 5
-20% by weight, more preferably 5-15% by weight,
Further, the viscosity at 20 ° C. of the 2% by weight aqueous solution is 1%.
It is 0 to 80 cps, preferably 20 to 75 cps, more preferably 30 to 70 cps. The partially saponified polyvinyl alcohol has a degree of saponification of 25 to 65 mol%, preferably 28 to 55 mol%, more preferably 30 to 50 mol%, and an average degree of polymerization of 200 to 1000, preferably 200 to 900. And more preferably 200 to 800. The dispersion stabilizer (B) comprising these components is added in an amount of 0.005 to 0.0 with respect to 100 parts by weight of the vinyl chloride monomer.
5 parts by weight, preferably 0.01 to 0.045 parts by weight, more preferably 0.01 to 0.04 parts by weight.

Here, when the methoxy substitution degree, hydroxypropoxy substitution degree and aqueous solution viscosity of the hydroxypropylmethylcellulose of the dispersion stabilizer (B) are out of the above ranges, the polymerization stability is poor, and the polymerization heat removal ratio of the reflux condenser is poor. 3
If it is 0% or more, the foaming phenomenon during polymerization becomes intense, causing problems such as increased scale adhesion to the reflux condenser. In addition, the fish eye of the molded product is also deteriorated. Further, the degree of saponification of the partially saponified polyvinyl alcohol of the dispersion stabilizer (B) is less than 25 mol%, or the average degree of polymerization is 2
If it is less than 00, the obtained particles are undesirably coarse and roll adhesion on a calendar becomes remarkable. On the other hand, if the degree of saponification exceeds 65 mol% or if the average degree of polymerization exceeds 1,000, fish eyes of the molded article deteriorate, which is not preferable. In addition, the amount used is 0.
If the amount is less than 005 parts by weight, the effect of improving fish eyes is not obtained. If the amount exceeds 0.05 parts by weight, when the heat removal rate of polymerization of the reflux condenser is set to 30% or more, the foaming phenomenon particularly during polymerization becomes severe, It is not preferable because scale adhesion to the condenser increases. Further, since the obtained vinyl chloride polymer is also finely divided, powder handling becomes difficult, which is not preferable.

The total amount of the dispersion stabilizer (A) and the dispersion stabilizer (B) used in the present invention is 100 parts by weight of the vinyl chloride monomer.
0.03 to 0.2 part by weight, preferably 0.04 to 0.18 part by weight, more preferably 0.04 to 0.1 part by weight based on part by weight.
0.15 parts by weight are used. Further, the weight ratio of the dispersion stabilizer (A) / (B) used in the present invention is 0.5 to 4, preferably 0.6 to 3.5, more preferably 0.6 to 3. .

Here, the sum of (A) and (B) is 0.03
If the amount is less than part by weight, polymerization stability is deteriorated and particles tend to be coarse, which is not preferable. On the other hand, when the amount exceeds 0.2 parts by weight, when the heat removal rate of polymerization of the reflux condenser is set to 30% or more, foaming to the reflux condenser during polymerization is particularly severe, and scale adheres to the reflux condenser. This is not preferable because the fish eye of the molded product is deteriorated. Further, the obtained vinyl chloride polymer is also unpreferable because the powder handling becomes difficult because the particles are also finely divided. When the weight ratio of (A) / (B) is less than 0.5, when the heat removal rate of polymerization of the reflux condenser is set to 30% or more, not only the foaming phenomenon during the polymerization is particularly severe, but also the polymerization stability. However, there is also a problem, and the particles tend to be coarse, which is not preferable. On the other hand, when the weight ratio of (A) / (B) is more than 4, the fish eye of the molded article is undesirably deteriorated.

In the present invention, the polymerization conversion is 10% by weight from the initial stage of polymerization, preferably 8% by weight from the initial stage of polymerization, and more preferably 6% by weight from the initial stage of polymerization by the following general formula (1). Replace the ammonium salt shown with 1
× 10 ^{-7 to} 0.01 parts by weight, preferably 1 × 10 ^{-6 to} 0.
001 parts by weight, more preferably 1 × 10 ^{−5 to} 0.000
Add 1 part by weight. Thereby, the porosity can be improved, and the residual monomer can be reduced. If the polymerization conversion exceeds 10% by weight and the above compound is added, or if the amount of the above compound is less than 1 × 10 ⁻⁷ parts by weight, there is no effect of improving porosity, so that the amount of residual monomer increases, which is not preferable. The amount of the ammonium salt added is 0.01
When the amount is more than the weight part, the effect of improving the porosity is saturated, and on the contrary, adverse effects such as coarsening of the particles and deterioration of the hue of the molded product appear, which is not preferable.

[0022]

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The ammonium salt represented by the above-mentioned general formula (1) used in the present invention has R ¹ , R ² , R
³ and R ⁴ are the same or different and each is a linear or branched alkyl group having 1 to 10 carbon atoms, specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec.
-Butyl, tert-butyl, n-pentyl, tert
-Pentyl, neopentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl,
4-methylpentyl, 2-ethylbutyl, 3-ethylbutyl, 1,1′-dimethylbutyl, n-heptyl, 1-
Methylhexyl, 2-methylhexyl, 1,1 ', 3-
Trimethylbutyl, n-octyl, 1-methylheptyl, 2-methylheptyl, 1,1 ', 3,3'-tetramethylbutyl, n-nonyl, 1-methyloctyl, 2-
Methyl octyl, 1-ethyl-1 ′, 3,3′-trimethylbutyl, n-decyl, 1-methyloctyl, 2-methyloctyl, 1,1 ′, 3,3′-tetramethylpentyl group, and the like. . X is any counter ion atom or compound, specifically, F, Br, Cl,
I, CN, OH, Br ₃ , BF ₄ , BH ₄ , B (C
_{6 H 5) 4, BH 3} CN, (C 6 H 5) 3 SnF 2, PF 6, C
10 ₄ , 10 ₄ , ClCrO ₃ , H ₂ PO ₄ , H ₂ PO ₂ , H
SO ₄ , NO ₃ , ReO ₄ , SCN, CF ₃ SO ₃ , OCO
CH ₃ and CH ₃ C ₆ H ₄ SO ₃ are exemplified.

The method of adding the ammonium salt is not particularly limited as long as the polymerization conversion is within the range of 10% by weight from the initial stage of the polymerization. For example, a solution obtained by dissolving the ammonium salt in water in a solid state, methanol Such as a method of batch addition, divisional addition, and continuous addition of those dissolved in an organic solvent.

In the present invention, in order to improve a vinyl chloride polymer so as to be suitable for calendering at a high temperature where further improvement in roll adhesion is required, a polyolefin, a paraffin, and a chlorinated hydrocarbon are used. The average particle size of at least one or more selected compounds is 3
It is preferable to add 0.001 to 0.3 parts by weight of a lubricant having a size of 00 μm or less based on 100 parts by weight of the vinyl chloride monomer at the beginning of polymerization, during polymerization, or after completion of polymerization. The average particle size of the lubricant is 300 μm or less, preferably 200 μm
m, more preferably 100 μm or less. 300
If it exceeds μm, there is a problem in the uniformity of dispersion of the lubricant particles,
This is not preferable because the effect of suppressing the occurrence of roll sticking on the calendar is greatly reduced. The lower limit of the particle size is not particularly limited, but is, for example, 0.1 μm or more. The amount of the lubricant added is preferably 0.002 to 0.2 parts by weight, more preferably 0.003 to 0.15 parts by weight.

Examples of the polyolefin used in the present invention include known polyolefins, for example, polyethylene wax, polypropylene wax, etc., and from the viewpoint of improving roll adhesion, those having a low molecular weight belonging to the category of wax are preferable, and particularly, those having low molecular weight are preferable. Polyethylene wax is particularly preferred. As the paraffin and the chlorinated hydrocarbon, known paraffins and chlorinated hydrocarbons added to a vinyl chloride resin are used, and examples thereof include natural paraffin having a melting point of 50 ° C. or higher, 2-chloronaphthalene, and the like. .

There are no particular restrictions on the timing of the addition of the above lubricant. For example, at the beginning of polymerization, during polymerization, in the state of a slurry after the recovery of unreacted vinyl chloride monomer, in the state of a wet cake after the dehydration of the slurry, For example, when the powder is in a powder state after the wet cake is dried. Among them, particularly at the beginning of polymerization, during the polymerization, when the above-mentioned lubricant is added during the slurry state after the completion of the polymerization, the effect of improving the roll adhesion is large,
The same effect of improving roll adhesion can be obtained with a small amount of addition compared to other addition times. Therefore, when the above lubricant is added at this time, the amount of the
0.001 to 0.3 parts by weight, preferably 0.002 to 0.15 parts by weight, more preferably 0.0 to 0 parts by weight.
A sufficient improvement effect can be obtained with 03 to 0.1 part by weight.

Here, the initial stage of the polymerization in the present invention is from the time when an aqueous medium, a vinyl chloride monomer or the like is charged into a polymerization vessel to before the polymerization is substantially started, that is, the polymerization conversion rate is less than 1% by weight. It means until the time. The term “during polymerization” refers to a period from a polymerization conversion of 1% by weight to a time before the unreacted vinyl chloride monomer at the time of completion of the polymerization is recovered. Furthermore, the state of the slurry state after the completion of the polymerization refers to a period from the time when the unreacted vinyl chloride monomer is recovered at the time when the polymerization is completed to the time when the discharged slurry is subjected to centrifugal dehydration.

The method of adding the above lubricant used in the present invention is not particularly limited. For example, a method in which the lubricant is emulsified in water or a solution in which the lubricant is dissolved in an organic solvent is added all at once while the lubricant is kept solid. , Split addition, continuous addition,
A method of spraying and the like can be mentioned.

In the present invention, a commonly used suspension polymerization method can be applied as it is, and specifically, for example, the following method is used.

A deionized water, a dispersion stabilizer and a polymerization initiator are charged into a pressure-resistant polymerization reactor provided with a stirrer, an outer jacket and a reflux condenser, and the pressure is reduced. Next, a vinyl chloride-based monomer is injected under pressure, and the polymerization is started by heating while stirring the inside of the polymerization vessel. The polymerization conditions at that time are, for example, a polymerization temperature of 20 to 90 ° C. and a polymerization time of 1 to 6 hours. After completion of the polymerization, the unreacted vinyl chloride-based monomer is recovered, and the slurry is taken out and dehydrated and dried to obtain a vinyl chloride-based polymer.

The polymerization initiator used in the present invention may be any of those generally used as a polymerization initiator in a suspension polymerization method, for example, tert-butyl peroxy neodecanoate, tert-hexyl peroxy neo. Decanoate, tert-hexylperoxypivalate, tert-butylperoxypivalate, α-cumylperoxyneodecanoate, tert-hexylperoxyneohexanoate, α, α′-bis (neodecanoyl Peroxy) diisopropylbenzene, 1,
1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, tert-hexyl peroxyglycolate, 1,1-dimethyl-3-hydroxybutyl peroxy Perester compounds such as oxyneodecanoate; diisopropyl peroxydicarbonate, di-2
-Ethylhexyl peroxydicarbonate, di-2-
Percarbonate compounds such as ethoxyethylperoxydicarbonate and dimethoxyisopropylperoxydicarbonate; peroxide compounds such as benzoyl peroxide, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and acetylcyclohexyl peroxide; 2,2 Examples include azo compounds such as' -azobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile, which can be used alone or in combination of two or more.

In the present invention, when the present invention is carried out, a vinyl monomer copolymerizable with a vinyl chloride monomer or a polymer graft polymerizable with a vinyl chloride monomer is added as necessary. And may be polymerized.

In the present invention, the vinyl chloride monomer is
A vinyl chloride monomer or a mixture of a vinyl monomer and a vinyl monomer copolymerizable therewith.

Examples of the vinyl monomer copolymerizable with the vinyl chloride monomer include vinyl esters such as vinyl acetate, vinyl propionate, vinyl caproate, vinyl laurate, and vinyl stearate; ethylene, propylene, Olefins such as isobutylene; alkyl or aryl vinyl ethers such as isobutyl vinyl ether, phenyl vinyl ether and octyl vinyl ether; halogenated olefins such as vinylidene chloride, vinyl fluoride, allyl chloride and vinyl bromide; ethyl acrylate;
-Butyl acrylate, n-butyl methacrylate, 2
Acrylic acid or methacrylic acid esters such as -ethylhexyl acrylate, 2-ethylhexyl methacrylate and stearyl methacrylate; acrylic acid, methacrylic acid, crotonic acid, acrylonitrile, maleic anhydride, and acrylic derivatives such as itaconic anhydride; These can be used alone or in combination of two or more.

Examples of the polymer which can be graft-copolymerized with a vinyl chloride monomer include ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer, chlorinated polyethylene, polyurethane, and polybutadiene-styrene. -Methyl methacrylate copolymer (MB
S), polybutadiene-acrylonitrile- (α-methyl) styrene copolymer (ABS), polybutyl acrylate, butyl rubber, polystyrene, styrene-butadiene copolymer, cross-linked acrylic rubber, and the like. It can be used in combination of the above.

In addition to the dispersion stabilizer used in the present invention, other dispersion stabilizers can be used without any problem as long as the effects of the present invention are not impaired. Soluble partially saponified polyvinyl alcohol; water-soluble cellulose such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose; acrylic acid polymer;
Water-soluble polymers such as methyl vinyl ether-maleic anhydride copolymer, styrene-maleic anhydride copolymer, and gelatin; oils such as sorbitan monolaurate, sorbitan monostearate, glycerin monostearate, and ethylene oxide propylene oxide block copolymer Soluble emulsifier, polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate,
Water-soluble emulsifiers such as sodium laurate,
These can be used alone or in combination of two or more.

In the present invention, the vinyl chloride polymer is
A substance mainly composed of a polymer obtained by polymerizing a vinyl chloride monomer or a mixture of a vinyl monomer copolymerizable with a vinyl chloride monomer, and a lubricant, a gelling improver as appropriate. Further, additives such as a pH adjuster, a chain transfer agent, an antistatic agent, a cross-linking agent, a defoaming agent, a stabilizer, a filler, an antioxidant, and a scale adhesion inhibitor may be added. These can be added at the beginning of the polymerization, during the polymerization, or after the polymerization.

The polymerization time in the present invention is within 6 hours,
Preferably, it is 1 to 6 hours, more preferably, 1 to 4 hours. By doing so, it is possible to realize the production of a vinyl chloride polymer having high productivity. Here, the polymerization time is the time from when the polymerization raw material is charged and the internal temperature reaches a predetermined temperature by raising the temperature to when the pressure in the polymerization vessel drops 1.8 kg / cm ² from the initial pressure. Is the polymerization time. In addition, even in the polymerization method in which the polymerization is terminated at a point where the decrease in the internal pressure is smaller than 1.8 kg / cm ² , when the polymerization is continued under normal conditions, the decrease in the internal pressure is reduced within 6 hours. A polymerization of 1.8 kg / cm ² is included in the scope of the present invention. Such polymerization is substantially the same as the polymerization method of the present invention in which the polymerization end time is defined as above within 6 hours after the above-described polymerization end time. Because it is different.

As the reflux condenser attached to the polymerization vessel used in the method of the present invention, a known condenser can be used. Regarding the control method, the heat removal ratio of the reflux condenser is controlled at 30% or more of the polymerization heat removal amount. Then, there is no particular limitation, and a known method, a method described in a document, or the like is applied. (For example, Saeki, Nagami, eds .: New Polymer Manufacturing Process (issued by the Industrial Research Institute), page 158, Table 6.5)

In the present invention, the stirrer of the polymerization vessel is not particularly limited, and a baffle may be used if desired. Examples of the stirrer include a turbine blade, a fan turbine blade, a Faudler blade, and a blue margin blade which are usually used for polymerization of a vinyl chloride monomer, and baffles include a finger type, a cylindrical type, a D type, and a loop type. You.

[0042]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The amounts of the dispersion stabilizers and the like shown in the table indicate parts by weight based on 100 parts by weight of the vinyl chloride monomer.

In the examples and comparative examples, the average particle size measurement, porosity measurement, residual monomer measurement, initial coloring property, fish eye and roll adhesiveness were evaluated by the following methods.

(Average Particle Size) The sieve was analyzed using a JIS standard wire mesh to give a 50% passing diameter.

(Porosity) The porosity (volume of pores inside the particles) was measured by measuring the volume of pores having a pore diameter of 0.05 to 5 μm using a porosimeter of mercury intrusion method (manufactured by Shimadzu Corporation). It was converted to the pore volume per gram of the polymer.

(Measurement of Residual Monomer) The vinyl chloride polymer was dissolved in tetrahydrofuran, and the content of the vinyl chloride monomer in the vinyl chloride polymer was measured by gas chromatography.

(Initial Colorability) Vinyl Chloride Polymer 100
3 parts by weight of a dibutyltin malate-based stabilizer and 0.2 parts by weight of a fatty acid ester-based lubricant are blended with respect to parts by weight,
150 g of the compound was kneaded with a 6-inch roll at a roll surface temperature of 150 ° C. for 5 minutes to obtain a 1 mm-thick sheet compact. Subsequently, the sheet compacts were laminated, and a 5 mm press compact was obtained by pressing at 180 ° C. under the conditions of preheating for 15 minutes, molding pressure of 50 kg / cm ² , and pressing time of 20 minutes.
The initial colorability was determined by measuring the yellow value (YI) of the molded product with a color difference meter. The smaller the value of YI, the better the initial coloring property.

(Fisheye) Vinyl chloride polymer 1
A sheet obtained by mixing 40 parts by weight of di-2-ethylhexyl phthalate, 3 parts by weight of a Ca-Zn composite metal soap stabilizer, and a small amount of ultramarine blue with 00 parts by weight, and kneading with a roll at 160 ° C. for 3 minutes. The number of fish eyes observed in 50 cm ² was counted.

(Roll Adhesion) Vinyl Chloride Polymer 10
4 parts by weight of a dibutyltin malate-based stabilizer and 1.5 parts by weight of a fatty acid ester-based lubricant were added to 0 parts by weight. This composition was kneaded with two 8-inch rolls at a surface temperature of 185 ° C. on a roll of 8 inches and kneaded for 5 minutes, and the sheet was taken out. Then, the same operation was repeated five times to evaluate the ease of peeling of the sheet. Evaluation criteria for calenderability ○ No sticking (peeling without any problem) △ Slightly sticking (easily peeling) × large sticking (slightly difficult to peel) ×× vigorous sticking (difficult to peel)

Examples 1 to 3 Deionized water 54 was added to a stainless steel polymerization vessel equipped with a stirrer having an inner volume of 120 m ³ , an outer jacket, and a reflux condenser.
000 kg, a dispersion stabilizer (A) shown in Table 1, a dispersion stabilizer (B), and n-butylammonium chloride as an ammonium salt were charged, and 18 kg of tert-hexylperoxypivalate was added thereto, and the pressure was reduced. Then, 36000 kg of vinyl chloride monomer was charged, the temperature was raised to 67 ° C. through hot water in the jacket while stirring the inside of the polymerization vessel, polymerization was started while maintaining this temperature, and cooling water was passed through the reflux condenser. While adjusting the load, the polymerization was advanced with the heat removal rate of the reflux condenser being 40% of the polymerization heat generation value.

When the pressure in the polymerization vessel dropped 2.0 kg / cm ² from the pressure in the steady state of the polymerization reaction, the unreacted vinyl chloride monomer was recovered. The polymerization time was 4 hours.

After discharging the slurry from the polymerization vessel, the slurry was sent to a demonomerization tower, and subjected to demonomerization treatment under the conditions shown in Table 1. Subsequently, when dehydration and drying were performed, 85%
A vinyl chloride polymer was obtained at a polymerization conversion of.

The evaluation results of the obtained vinyl chloride polymer are shown in Table 1. The obtained vinyl chloride polymer had high production efficiency, was porous, had little residual monomer, and was excellent in initial coloring, fisheye, and roll adhesiveness. The scale adhesion condition in the reflux condenser was good.

Example 4 The same operation as in Example 1 was carried out except that the ammonium salt shown in Table 1 was added to the polymerization system at a polymerization conversion of 5% by weight.
The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%. Table 1 shows the evaluation results of the obtained vinyl chloride polymers. The obtained vinyl chloride polymer had high production efficiency, was porous, had little residual monomer, and was excellent in initial coloring, fisheye, and roll adhesiveness.
The scale adhesion condition in the reflux condenser was good.

Example 5 Example 1 was repeated except that the lubricants shown in Table 1 were added as powders to the dehydrated vinyl chloride polymer wet cake and fluidized and dried.
The same operation as described above was performed. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 1 shows the evaluation results of the vinyl chloride polymer. The obtained vinyl chloride polymer has high production efficiency,
It was porous and had little residual monomer, and was excellent in initial coloring, fisheye and roll adhesion. The scale adhesion condition in the reflux condenser was good.

Example 6 The procedure of Example 1 was repeated except that the lubricant shown in Table 1 was converted into an emulsified aqueous solution (concentration of the aqueous solution of the lubricant was 30% by weight) at the beginning of polymerization (before the temperature was raised). The same operation was performed. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 1 shows the evaluation results of the vinyl chloride polymer. The obtained vinyl chloride polymer has high production efficiency,
It was porous and had little residual monomer, and was excellent in initial coloring, fisheye and roll adhesion. The scale adhesion condition in the reflux condenser was good.

Example 7 The same procedure as in Example 1 was carried out except that a lubricant shown in Table 1 in the form of an aqueous emulsion solution (concentration of lubricant aqueous solution: 30% by weight) was added to the polymerization system at a polymerization conversion rate of 30% by weight. The operation was performed. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 1 shows the evaluation results of the vinyl chloride polymer. The obtained vinyl chloride polymer has high production efficiency,
It was porous and had little residual monomer, and was excellent in initial coloring, fisheye and roll adhesion. The scale adhesion condition in the reflux condenser was good.

Example 8 Except that the lubricant shown in Table 1 in the form of an aqueous emulsion solution (concentration of lubricant aqueous solution: 30% by weight) was added to the vinyl chloride polymer slurry after recovering the unreacted vinyl chloride monomer, The same operation as in Example 1 was performed. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 1 shows the evaluation results of the vinyl chloride polymer. The obtained vinyl chloride polymer has high production efficiency,
It was porous and had little residual monomer, and was excellent in initial coloring, fisheye and roll adhesion. The scale adhesion condition in the reflux condenser was good.

Comparative Example 1 The same operation as in Example 1 was performed except that the ammonium salt shown in Table 2 was not added. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 2 shows the evaluation results of the obtained vinyl chloride polymer. The obtained vinyl chloride polymer had high production efficiency and was excellent in initial coloring property, fish eye, and roll adhesiveness, but was low in porosity, had many residual monomers, and was inferior in demonomerization properties. However, the scale adhesion condition in the reflux condenser was good.

Comparative Example 2 Example 1 was repeated except that the ammonium salt shown in Table 2 was added in an amount of 0.02 parts by weight based on 100 parts by weight of the vinyl chloride monomer.
The same operation as described above was performed. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 2 shows the results of the evaluation of the obtained vinyl chloride polymer. The resulting vinyl chloride polymer had high production efficiency, was porous, had little residual monomer, and had excellent roll adhesion, but had poor initial coloring and fisheye. Also, the particle size tends to be coarse, and the powder characteristics were not satisfied. However, the scale adhesion condition in the reflux condenser was good.

Comparative Example 3 The timing of adding the ammonium salt shown in Table 2 was determined by changing the polymerization conversion rate to 20.
The same operation as in Example 1 was performed, except that it was added to the polymerization system by weight%. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 2 shows the evaluation results of the obtained vinyl chloride polymer.

The obtained vinyl chloride polymer was high in production efficiency and excellent in initial coloring property, fish eye and roll adhesiveness. However, it had low porosity, a large amount of residual monomers, and was inferior in demonomerization properties. there were. However, the scale adhesion condition in the reflux condenser was good.

Comparative Example 4 The same operation as in Example 1 was performed, except that the dispersion stabilizer (A) shown in Table 2 was changed. The polymerization time was 4 hours.
The polymerization conversion after dehydration and drying was 85%.

Table 2 shows the evaluation results of the obtained vinyl chloride polymer. The obtained vinyl chloride polymer had high production efficiency, excellent initial coloring properties, and excellent roll adhesiveness, but had low porosity, had a large amount of residual monomer, and had poor demonomerization properties, and also had poor fish eyes. Met. Also, the particle size tends to be coarse, and the powder characteristics were not satisfied. However, the scale adhesion condition in the reflux condenser was good.

Comparative Example 5 The same operation as in Example 1 was carried out except that the addition amount of the dispersion stabilizer (A) shown in Table 2 was changed to 0.06 parts by weight and the dispersion stabilizer (B) was changed. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 2 shows the evaluation results of the obtained vinyl chloride polymer. The obtained vinyl chloride polymer had high production efficiency, was porous, had little residual monomer, and had excellent initial coloring properties, but had poor fisheye and roll adhesion. Also, the particle size tends to be coarse, and the powder characteristics were not satisfied. Further, when the inside of the reflux condenser was observed, a small amount of film scale was formed on the wall surface.

Comparative Example 6 The same operation as in Example 1 was carried out except that the addition amount of the dispersion stabilizer (A) shown in Table 3 was 0.08 parts by weight and the dispersion stabilizer (B) was not added. Was. The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 3 shows the evaluation results of the obtained vinyl chloride polymer. The obtained vinyl chloride polymer had high production efficiency, was porous, had few residual monomers, and was excellent in initial coloring property and roll adhesiveness, but was inferior in fisheye. Also, the particle size tends to be coarse, and the powder characteristics were not satisfied. However, the scale adhesion condition in the reflux condenser was good.

Comparative Example 7 The same operation as in Example 2 was performed except that the weight ratio of the dispersion stabilizer (A) to the dispersion stabilizer (B) shown in Table 3 was changed.
The polymerization time was 4 hours. The polymerization conversion after dehydration and drying was 85%.

Table 3 shows the evaluation results of the obtained vinyl chloride polymer. The obtained vinyl chloride polymer had high production efficiency, was porous, had few residual monomers, and was excellent in initial coloring property and roll adhesiveness, but was inferior in fisheye. However, the scale adhesion condition in the reflux condenser was good.

[0078]

[Table 1]

[0079]

[Table 2]

[0080]

As described above, according to the present invention,
A polymerization vessel having an internal volume of 100 m ³ or more equipped with a stirrer, an outer jacket and a reflux condenser was used. The amount of heat removed by the reflux condenser during polymerization was 30% or more of the total heat removal, and the polymerization time was 6 hours. When the vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator under the polymerization conditions described below, a predetermined dispersion stabilizer is used, and an alkali metal and / or alkali metal is used. Add an earth metal hydroxide. Further, a lubricant made of polyolefin or the like and having an average particle size of 300 μm or less is added at the beginning of polymerization, during polymerization, or in a slurry state after completion of polymerization. For this reason, it is possible to produce a vinyl chloride polymer which is porous and excellent in demonomerization property, has little roll stickiness during calendering processing, and has excellent fisheye and hue of the molded product at high speed and high productivity. .

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4J011 AA01 AA05 AA08 AB03 DA03 DB12 DB16 DB23 JA07 JA08 JB01 JB26 PA36 PA56 PA64 PA66 PB33 PB40 PC01 PC07 PC11

Claims (3)

[Claims] 1. A polymerization vessel having an internal volume of 100 m ³ or more provided with a stirrer, an outer jacket and a reflux condenser,
Under polymerization conditions in which the amount of heat removed by the reflux condenser during polymerization is 30% or more of the total amount of heat removed and the polymerization time is within 6 hours, the vinyl chloride-based monomer is added in the presence of an oil-soluble polymerization initiator. (A) Degree of saponification: 75 to 90 mol%, average degree of polymerization: 1500
-3000 partially-saponified polyvinyl alcohol in an amount of 0.02-0.15 per 100 parts by weight of the vinyl chloride monomer.
Parts by weight (B) hydroxypropyl methylcellulose and / or saponification wherein the degree of methoxy substitution is 15 to 40% by weight, the degree of hydroxypropoxy substitution is 5 to 25% by weight, and the viscosity of the 2% by weight aqueous solution at 20 ° C. is 10 to 80 cps. Of partially saponified polyvinyl alcohol having a degree of polymerization of 25 to 65 mol% and an average degree of polymerization of 200 to 1000
0.005 to 0.05 parts by weight based on 00 parts by weight, and the total of (A) and (B) is 0.03 to 0.2 parts by weight based on 100 parts by weight of the vinyl chloride monomer, (A) /
The weight ratio of (B) is from 0.5 to 4, and an ammonium salt represented by the following general formula (1) is added to 100 parts by weight of the vinyl chloride monomer during the polymerization conversion of 10% from the initial stage of polymerization. A method for producing a vinyl chloride-based polymer, characterized by adding 1 × 10 ^{−7 to} 0.01 part by weight of the polymer. Embedded image (R ¹ , R ² , R ³ and R ⁴ are the same or different and each have 1 carbon atom
X represents a linear or branched alkyl group of 10 to 10, and X represents any counter ion atom or compound. ) 2. A slurry comprising at least one compound selected from the group consisting of polyolefins, paraffins, and chlorinated hydrocarbons and having a mean particle size of 300 μm or less in a slurry at the beginning of polymerization, during polymerization, or after completion of polymerization. The method for producing a vinyl chloride polymer composition according to claim 1, wherein 0.001 to 0.3 parts by weight is added to 100 parts by weight of the vinyl chloride monomer in the state. 3. A vinyl chloride polymer produced by the method for producing a vinyl chloride polymer according to claim 1 or 2.