JPH11166004A - Production of chlorinated vinyl chloride-based resin and vinyl chloride-based resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chlorinated vinyl chloride-based resin excellent in gelation property and heat resistance by chlorinating a vinyl chloride-based resin obtained by performing an emulsion polymerization of monomer in the presence of a dispersing agent and an oil-soluble polymerization initiator under a specific conduction. SOLUTION: This method for producing the chlorinated vinyl chloride-based polymer is to chlorinate (A) a vinyl chloride-based resin obtained by starting an emulsion polymerization of (i) >=50 wt.% vinyl chloride monomer with (ii) a monomer capable of copolymerizing with the component (A) as necessary in the presence of (iii) a dispersing agent and (iv) an oil-soluble polymerization initiator, at a temperature lower than a polymerization temperature ( deg.C) calculated from an averaged degree of polymerization (A) and the equation: B=0.016A-41.44LN(A)+327.7 by 5-20 deg.C [A is the averaged degree of polymerization; B is a polymerization temperature ( deg.C); LN(A) is a natural logarithm taking (e) as a base], adding (v) a chain transfer agent at 3-20% polymerization conversion rate, and having A±100 averaged degree of polymerization, e.g. in a state of suspension, a state of being dissolved with a solvent or in a solid state by bringing into contact with (B) chlorine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Vinyl chloride resin (hereinafter referred to as PVC resin) is used in many fields as a material having excellent mechanical strength, weather resistance and chemical resistance. However,
A chlorinated vinyl chloride resin (hereinafter referred to as C) in which the heat resistance is improved by chlorinating a PVC resin due to poor heat resistance.
PVC resin) has been developed.

[0003] PVC resin has a low heat distortion temperature and the maximum usable temperature is around 60 to 70 ° C, so that it cannot be used for hot water, whereas CPVC resin has a heat distortion temperature of 20 times higher than that of PVC resin. Because it is as high as ~ 40 ° C, it can be used for hot water.
It is suitably used for heat-resistant valves and the like.

However, since the CPVC resin has a high heat deformation temperature, a high temperature and a strong shearing force are required for gelling during the molding processability, and there is a tendency that it is easily decomposed and colored during the molding process. Therefore, the CPVC resin is often produced in a narrow molding process width and in an insufficiently gelled state, and it cannot be said that the performance of the material can be sufficiently exhibited. Further, in addition to the demand for improving the gelation performance, higher heat resistance is also required.

In order to solve such problems, for example, Japanese Patent Application Laid-Open No. 49-6080 discloses a method of using a suspension stabilizer comprising an ionic emulsifier, a water-soluble metal salt and a water-soluble polymer dispersant. A method for chlorinating a PVC resin composed of aggregates consisting of basic particles of about 1 μm is disclosed (a proposal for improvement of resin particles). However, in this method, the gelling performance at the time of molding has been improved, but it is not yet sufficient, and a large amount of scale is generated at the time of polymerization, which adheres to the wall surface of the polymerization tank to reduce the heat removal effect. There is a problem that the scale removal operation is required for the inhibition.

[0006] JP-A-5-132602 discloses a CP.
A method is disclosed in which a VC resin and a PVC resin are blended so as to be within a specific viscosity range to obtain high heat resistance (improvement proposal by resin blending). However, in this method, improvement of heat resistance of about 3 to 4 ° C. in Vicat value and slight improvement of gelation performance due to improvement of melt viscosity can be expected. Gelling performance was not sufficiently achieved.

[0007] JP-A-6-128320 discloses PV
As a method for chlorinating C resin, a chlorination method in two steps (two-step post-chlorination method) is disclosed. This method aims at obtaining a CPVC resin having high heat resistance by increasing the chlorine content to 70 to 75% by weight (improvement proposal by a high chlorination method). However, in this method, although high heat resistance can be expected according to the chlorine content, there is no means to prevent the deterioration of gelation performance predicted by high chlorination, so that high heat resistance is not exhibited. And gelation performance were not achieved on a practical level.

In Japanese Patent Application Laid-Open No. 1-217008, the range of the average particle size and the porosity of the PVC resin is limited in the photochlorination reaction method by intermittent irradiation. This proposal aims to make the chlorination reaction uniform within the resin particles by promoting the diffusion of chlorine in the non-irradiation step. However, since the surface properties (skin layer) of the resin particles are not considered, the heat resistance of the obtained CPVC resin is improved, but the gelation performance has not been improved.

Japanese Unexamined Patent Publications Nos. 9-118713 and 9-132612 propose proposals focusing on the surface properties and specific surface area of resin particles. JP-A-9-118
No. 713 proposes chlorination with a vinyl chloride resin having a large surface area of 1.3 to 8 m ² / g in terms of specific surface area by the BET method. As a result, improvement in both properties of heat resistance and gelation, which are competing with each other, is recognized, but it is not satisfactory for heat-resistant molded products requiring higher heat resistance. JP-A-9-
No. 132612 discloses a resin particle surface property (skin layer).
And a method of chlorinating a vinyl chloride resin having substantially no skin layer or a thin skin layer.
As in the above-mentioned Japanese Patent Application Laid-Open No. Hei 9-118713, improvements in both properties of heat resistance and gelling are observed, but they were not satisfactory for heat-resistant molded products requiring higher heat resistance.

[0010] Proposals for using a chain transfer agent during polymerization for the purpose of improving moldability are disclosed in, for example, JP-A-57-192411 and JP-A-57-195107, and JP-A-7-188315. ing. JP 57
-192411 and JP-A-57-19510
No. 7, for the purpose of improving moldability, a resin having a specific polymerization degree is produced (first-stage polymerization), and then the polymerization degree is increased or decreased from the first-stage polymerization (second-stage polymerization). A) a process for producing a vinyl chloride resin by multistage polymerization comprising the steps of: When the vinyl chloride resin according to this method is used as a vinyl chloride resin to be subjected to chlorination, although the moldability is improved, a relatively high polymerization degree portion and a low polymerization portion are relatively present in the vinyl chloride resin particles. There is a problem that high heat resistance cannot be obtained even when chlorination is performed by a known chlorination method.

JP-A-7-188315 discloses a method for producing a vinyl chloride resin in which the polymerization temperature is increased and a chain transfer agent is added for the purpose of improving the gelling property during processing. . In this method, a chain transfer agent is added so that a vinyl chloride resin having a desired degree of polymerization is finally obtained. However, while the polymerization temperature is continuously changed, the chain transfer agent has a specific polymerization conversion rate. Is added all at once. When a vinyl chloride resin according to this method is used as the vinyl chloride resin to be subjected to chlorination, the moldability is improved, but the above-mentioned JP-A-57-19 is used.
For the same reason as described in JP-A-2411 and JP-A-57-195107, there is a problem that high heat resistance cannot be obtained even if chlorination is performed by a known chlorination method.

[0012]

SUMMARY OF THE INVENTION In view of the above, the present invention focuses on the molecular weight distribution and crystallinity on the surface and inside of a vinyl chloride resin, thereby controlling the distribution of chlorination, thereby improving gelation. An object of the present invention is to provide a method for producing a chlorinated vinyl chloride-based resin having excellent curing performance and heat resistance.

[0013]

The present invention relates to a method for producing a chlorinated vinyl chloride resin by chlorinating a vinyl chloride resin, wherein the vinyl chloride resin comprises a dispersant and an oil-soluble polymerization initiator. Is obtained by subjecting a monomer to suspension polymerization in the presence of the above. In the suspension polymerization, a polymerization temperature B obtained from an average degree of polymerization A by the following formula (1) is used.
The polymerization is started at a temperature of 5 to 20 ° C. lower than (° C.), and when the polymerization conversion is 3 to 20%, the polymerization is performed by adding a chain transfer agent. And a method for producing a chlorinated vinyl chloride resin having an average degree of polymerization of A ± 100. B = 0.016A−41.44LN (A) +327.7 (1) (where A represents the average degree of polymerization, B represents the polymerization temperature (° C.), and LN (A) has e as the bottom. The present invention will be described in detail below.

The present invention is a method for producing a chlorinated vinyl chloride resin obtained by chlorinating a vinyl chloride resin. In the present invention, the vinyl chloride resin means a homopolymer of a vinyl chloride monomer, and a copolymer of a vinyl chloride monomer at 50% by weight or more and a monomer copolymerizable therewith. I do.

The monomer copolymerizable with the above-mentioned vinyl chloride monomer is not particularly restricted but includes, for example, alkyl vinyl esters such as vinyl acetate;
Monoolefins; alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and octyl acrylate; alkyl vinyl ethers; maleimides, vinylidene chloride, styrene, and the like, and at least one of these is used. it can.

In general, it is known that in the production of a vinyl chloride resin, the degree of polymerization or the molecular weight of the vinyl chloride resin is generally determined by the polymerization temperature during the polymerization of a monomer such as vinyl chloride. I have. This is because, in the radical polymerization of monomers such as vinyl chloride, the probability that a polymer is generated by the chain transfer of the radical to the monomer is high, and the chain transfer constant of the radical to the monomer is a temperature. This is because it is a function of ("Polyvinyl chloride resin-basics and applications", p. 65 (edited by Kinki Chemical Association Vinyl Subcommittee, published by Nikkan Kogyo Shimbun, 1988)).

For example, if the desired average degree of polymerization A is about 10
The production of the vinyl chloride resin No. 00 is carried out at a polymerization temperature of about 57 ° C. Similarly, those having an average degree of polymerization A of about 1400 are about 50 ° C, those having an average degree of polymerization A of 800 are about 64 ° C, and those having an average degree of polymerization A of 500 are about 78 ° C.
At the polymerization temperature.

In the above case, the relational expression between the polymerization temperature and the average degree of polymerization can be expressed by the following equation (1). B = 0.016A−41.44LN (A) +327.7 (1) (where A represents the average degree of polymerization, B represents the polymerization temperature (° C.), and LN (A) has e as the bottom. Represents the natural logarithm.)

In the present invention, the polymerization temperature B (° C.) obtained from the average polymerization degree A by the above formula (1) is 5 to 2 times.
The polymerization is initiated at a temperature lower by 0 ° C., and the polymerization conversion is 3 to 2
At 0%, suspension polymerization is carried out by adding a chain transfer agent. In the present invention, the degree of polymerization is
Refers to the average degree of polymerization calculated from the specific viscosity according to JIS K6721.

On the other hand, it has been reported that the crystallinity of a vinyl chloride resin is about 8% at a polymerization temperature of about 57 ° C. and decreases by 1.5% when the polymerization temperature is increased by 10 ° C. (“Polychlorinated resin”). Vinyl Resins-Basics and Applications ”, p. 70 (edited by Kinki Chemical Association Vinyl Subcommittee, Nikkan Kogyo Shimbun, 198
8 years))).

In the present invention, in view of the relationship between the average polymerization degree and the polymerization temperature and the relationship between the crystallinity and the polymerization temperature, the polymerization is carried out at a polymerization temperature 5 to 20 ° C. lower than the usual polymerization temperature B (° C.). If it is carried out, the degree of polymerization of the obtained vinyl chloride resin is increased, but by adding a chain transfer agent, a vinyl chloride resin having an average degree of polymerization around A can be obtained.

By conducting the polymerization reaction at a low temperature as described above, an increase in crystallinity can be expected. It is an object of the polymerization operation to obtain essentially the same degree of polymerization and molecular weight as in the case where the above-mentioned polymerization operation is not performed, and to increase the crystallinity. This increase in crystallinity plays an important role during chlorination. That is, chlorine is not easily diffused into the crystal part. Therefore, the chlorination reaction proceeds intensively in an amorphous portion other than the crystalline portion. Thereby, the chlorination distribution can improve the heat distortion temperature as a filler effect.

When the polymerization temperature exceeds (B ° C.-5 ° C.), the crystallinity of the produced vinyl chloride resin is poorly increased, and the heat deformation temperature as a filler effect is improved during the chlorination reaction. Is not seen. If it is less than (B ° C-20 ° C), an increase in heat deformation temperature due to crystallinity is recognized, but it is not preferable because the crystal region becomes excessively large and the gelling property decreases. In the present invention, the polymerization temperature is preferably in the range of about 35 to about 85 ° C.

The polymerization temperature before the addition of the chain transfer agent is preferably adjusted to a temperature higher by 0 to 5 ° C. than the polymerization temperature after the addition of the chain transfer agent. Originally,
Before the addition, the polymerization temperature is high, so the polymerization temperature should be adjusted so that the molecular weight becomes completely the same before and after the addition of the chain transfer agent.However, since the heat capacity of the contents of the polymerization vessel is large, it is adjusted to the above range. Is preferred. In order to match the degree of polymerization before and after the addition of the chain transfer agent, it is desirable to set the temperature in consideration of the initial polymerization, that is, the increase in the degree of polymerization before the addition of the chain transfer agent.

In the present invention, the above-mentioned addition operation of the chain transfer agent is performed when the polymerization conversion is 3 to 20%. Thereby, at the time of the chlorination reaction, it is possible to obtain an improvement in the heat distortion temperature as a filler effect for substantially most of the resin particle region.

If added when the polymerization conversion is less than 3%, primary particles having a fine particle diameter in the initial stage of polymerization are aggregated,
Since the growth process is inhibited, the particle size distribution is undesirably widened. If the polymerization conversion rate exceeds 20%, the effect of crystallinity due to chain transfer is reduced, and the heat resistance of the chlorinated vinyl chloride resin is not improved. Preferably, the polymerization conversion is 5 to 15%.

As the chain transfer agent, known substances can be used, for example, saturated hydrocarbon compounds such as pentane and heptane; unsaturated hydrocarbon compounds such as 2-pentene; chlorinated carbon tetrachloride, trichloroethylene and the like. Hydrocarbon compounds; aldehydes such as propionaldehyde and butyraldehyde; 2-mercaptoethanol, dodecylmercaptan, octylmercaptan, α-thioglycerol, ethanediol, propanediol, thioglycolic acid, thiolactic acid, and n-butyl thioglycolate Organic mercaptans such as esters are included. Above all, 2-
Organic mercaptans such as mercaptoethanol, dodecylmercaptan, octylmercaptan and thioglycolic acid are preferred.

Since the purpose of adjusting the degree of polymerization is to adjust the amount of the chain transfer agent, the amount is determined in consideration of the degree of polymerization. The amount is preferably from 10 to 20,000 ppm based on the monomer weight part. More preferably, it is 30 to 3000 ppm. The method for adding the chain transfer agent is not particularly limited as long as it is within the range of the addition time, but the chain transfer agent may be added at a time, or a continuous or intermittent dropping method may be adopted.

The degree of polymerization of the obtained vinyl chloride resin is as follows:
(Average degree of polymerization A ± 100). (Average degree of polymerization A + 1
When it exceeds 00), the heat resistance is satisfactory, but the gelling property is reduced. If it is less than (average degree of polymerization A-100), the gelling property is satisfactory, but the heat resistance is undesirably reduced.

The average degree of polymerization A is determined by the physical properties and performance required for the intended use of the vinyl chloride resin.
2500 is preferred.

In the present invention, a monomer such as vinyl chloride is subjected to suspension polymerization in the presence of a dispersant and an oil-soluble polymerization initiator. The dispersant is not particularly limited, and is generally a PVC.
Known dispersants used for polymerizing resins can be used. For example, in addition to partially saponified polyvinyl acetate, water-soluble polymer compounds such as polyethylene oxide, acrylic acid, and gelatin; water-soluble cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose; sorbitan monolaurate And water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate. These may be used alone or in combination of two or more.

Among them, partially saponified polyvinyl acetate (a)
And at least one selected from the group consisting of cellulose derivatives (b). Various dispersants selected from the partially saponified polyvinyl acetate (a) and the cellulose derivative (b) may be used alone, or two or more of these may be used in combination.

The partially saponified polyvinyl acetate (a) preferably has a saponification degree of 60 to 90 mol%. Saponification degree 6
If it is less than 0 mol%, the oil solubility becomes strong and the ability to disperse monomers such as vinyl chloride is insufficient, so that the resulting P
The VC resin has a large number of coarse particles. If it exceeds 90 mol%, the protective colloid property becomes strong, so that a strong hard shell (skin layer) is formed on the particle surface, and at the same time, the pore area (BET specific surface area) in the PVC resin particles does not increase. Therefore, the reaction rate in the subsequent gel chlorination does not sufficiently increase, and the gelation characteristics of the obtained chlorinated vinyl chloride resin do not improve. More preferably, it is 70 to 85 mol%.

The average degree of polymerization of the partially saponified polyvinyl acetate (a) is preferably from 500 to 3000, more preferably from 700 to 1500. If the average degree of polymerization is less than 500, the dispersing ability of the monomer is lacking, and the PVC resin tends to become coarse particles or blocks. If it exceeds 3,000, the skin layer becomes thicker and the porosity (micropore area) becomes insufficient, so that the chlorination characteristics afterwards cannot be sufficiently exhibited, so that improvement in the moldability cannot be expected.

The amount of the dispersant added is preferably from 100 to 30,000 ppm based on the weight of the monomer. When the partially saponified polyvinyl acetate (a) is used, it is more preferably added in an amount of 150 to 2,000 ppm based on the weight of the monomer. If it is less than 150 ppm, the oil droplets of the monomer become unstable, so that the PVC resin tends to be block-shaped.
If it exceeds 2,000 ppm, the skin layer on the surface of the PVC resin particles becomes too thick, so that the subsequent improvement in chlorination properties cannot be expected and the formability does not improve.

When the above-mentioned cellulose derivative (b) is used, it is more preferable to use 150 parts by weight based on the monomer weight.
Add ~ 2000 ppm. When the amount is less than 150 ppm, the oil droplets of the monomer become unstable, so that the PVC resin tends to be block-shaped.
The skin layer on the surface of the C-resin particles becomes thick, and it is not possible to improve the chlorination characteristics later, and the moldability is not improved.

The oil-soluble polymerization initiator is not particularly limited, and a known radical initiator generally used for polymerization of a PVC resin can be used. For example, t-butyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-hexyl peroxy pivalate, α
-Cumyl peroxy neodecanoate, t-hexyl neohexanoate, 2,4,4-trimethylpentyl-
Perester compounds such as 2-peroxy-2-neodecanoate; diisopropyl peroxydicarbonate;
Percarbonate compounds such as di-2-ethylhexylperoxydicarbonate, di-2-ethoxyethylperoxydicarbonate and dimethoxyisopropylperoxydicarbonate; decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, cumene hydroperoxide , Cyclohexanone peroxide,
Peroxide compounds such as 2,4-dichlorobenzoyl peroxide, p-menthane hydroperoxide, 3,5,5-trimethylhexanoyl peroxide and isobutyl peroxide; α, α′-azobisisobutyronitrile, α, α Examples include azo compounds such as α′-azobis (dimethylvaleronitrile) and α, α′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and at least one of them can be used.

In the present invention, the suspension polymerization can be carried out in an aqueous medium. The aqueous medium is not particularly limited, and may be, for example, water alone or a mixture of water and an organic solvent. Examples of the organic solvent include lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; saturated aliphatic hydrocarbons such as n-pentane, iso-pentane, n-hexane and n-heptane; dichloroethylene, trichloroethylene, Chlorine-containing solvents such as carbon tetrachloride are exemplified.

The above suspension polymerization further has an HLB value of 3 to 1
At least one selected from the group consisting of sorbitan higher fatty acid ester (c) and anionic emulsifier (d)
Kinds of emulsifiers, higher fatty acids having 8 to 25 carbon atoms (e), and 0.1% by weight aqueous solution at normal temperature and pressure are 10 to 2%.
It is preferably carried out in the presence of a thickener (f) having a Brookfields viscosity of 00 cps.

The above sorbitan higher fatty acid ester (c)
Has an HLB value of 3 to 10. If it is less than 3, the lipophilicity is so high that the emulsifying and dispersing ability of the monomer in water is low, and the particle size distribution of the obtained PVC resin is wide including coarse particles. If it exceeds 10, the oil droplets of the monomer during polymerization become unstable due to high hydrophilicity, and aggregation of the monomer particles is likely to occur, and the PVC resin becomes an aggregate of block-like and coarse particles. Preferably, it is 4-9.

The sorbitan higher fatty acid ester (c) having an HLB value of 3 to 10 includes, for example, sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate Sorbitan saturated higher fatty acid esters such as stearate, unsaturated higher fatty acid esters and the like can be mentioned, and at least one of them can be used.

The above sorbitan higher fatty acid ester (c)
Is added in an amount of 500 to 5 parts by weight based on the weight of the monomer.
000 ppm is preferable, and 800 to 25 is more preferable.
00 ppm. If it is less than 500 ppm, the skin layer is formed thick, lacks porosity, and molding processability becomes poor. If it exceeds 5000 ppm, the particle size distribution is wide,
Resin scale adheres to the inner wall of the polymerization vessel.

Examples of the above anionic emulsifier (d) include fatty acid salts such as sodium stearate soap; alkyl sulfate salts such as sodium lauryl sulfate; alkyl benzene sulfonates such as sodium dodecylbenzene sulfonate; octylnaphthalene sulfonic acid. Alkyl naphthalene sulfonates such as sodium; alkyl sulfosuccinates such as sodium didodecyl sulfosuccinate;
Alkyl diphenyl ether disulfonate; alkyl phosphate; polyoxyethylene alkyl sulfate;
Naphthalene sulfonic acid formalin condensate; special polycarboxylic acid type polymer surfactant; polyoxyethylene alkyl phosphate; reactive surfactant; and the like, and at least one of them is used.

The amount of the anionic emulsifier (d) added is
The amount is preferably from 1 to 3000 ppm, more preferably from 3 to 2000 ppm, based on the monomer weight part. 1pp
If it is less than m, the skin layer of the PVC resin particles is formed to be thick, the porosity is insufficient, and the BET specific surface area is reduced, so that the effect of improving the moldability is reduced. 300
If it exceeds 0 ppm, the particle size distribution becomes wide, a large amount of resin scale adheres to the inner wall of the polymerization vessel, and sometimes the PVC resin particles are blocked, and a vinyl chloride resin cannot be obtained.

In the present invention, the HLB value is 3 to 1
Various emulsifiers selected from the sorbitan higher fatty acid ester (c) of No. 0 and the above-mentioned anionic emulsifier (d) may be used, or two or more of these emulsifiers may be used in combination. When the above-mentioned sorbitan higher fatty acid ester (c) having an HLB value of 3 to 10 and the anionic emulsifier (d) are used in combination, the addition amount is 10 to 400.
0 ppm is preferable, and more preferably, 15 to 2000
ppm.

The higher fatty acid having 8 to 25 carbon atoms (e)
As long as the effect is not reduced by the degree of unsaturation and branching of the main chain and the number of carbon atoms is 8 to 25, straight-chain saturated fatty acids are preferred. More preferably,
It has 11 to 22 carbon atoms. When the number of carbon atoms is less than 8, the higher fatty acid is not distributed to an oily layer of a monomer such as vinyl chloride during polymerization due to hydrophilicity, and does not exhibit a gelation promoting effect. If the number of carbon atoms exceeds 25, the melting point of the higher fatty acid increases, so that it is difficult to exhibit the gelation promoting effect even at the temperature of molding the PVC resin.

The higher fatty acid having 8 to 25 carbon atoms (e)
Examples thereof include isostearic acid, stearic acid, n-heptadecanoic acid, palmitic acid, n-pentadecanoic acid, myristic acid, arginic acid, nonadecanoic acid, n-tridecanoic acid, lauric acid, undecylic acid, and the like. Seeds can be used. The amount of the higher fatty acid (e) having 8 to 25 carbon atoms is based on the monomer weight part.
300-20,000 ppm is preferred.

Examples of the thickener (f) in which a 0.1% by weight aqueous solution at ordinary temperature and pressure has a Brookfield viscosity of 10 to 200 cps include polyethylene oxide, polyvinylpyrrolidone, polyacrylamide, and the like.
Polyacrylamide copolymers, crosslinked (meth) acrylic resins, methylcellulose calcium, sodium starch glycolate, sodium starch phosphate, sodium alginate, propylene glycol alginate, sodium carboxymethylcellulose, carboxymethylcellulose calcium, and the like. At least one of the following water-soluble thickeners can be used.

Among those exemplified as the thickener (f), the polyethylene oxide preferably has an average molecular weight of 1.7 to 5.5 million. Average molecular weight 43
When 100,000 to 4.8 million polyethylene oxide is converted to a 0.1% by weight aqueous solution, the Brookfield's viscosity becomes 12 cp.
s. The polyacrylamide has an average molecular weight of 8
It is preferably from 100,000 to 14,000,000. Average molecular weight is 1
When 2 million to 14 million polyacrylamide is converted to a 0.1% by weight aqueous solution, the Brookfield viscosity becomes 51c.
ps.

The Brookfield's viscosity of the thickener (f) in a 0.1% by weight aqueous solution is 10 to 200 cps, more preferably 11 to 140 cps. The viscosity of the aqueous solution is less than 10 cps or 200 cp
If it exceeds s, the particle size distribution of the obtained PVC resin will be poor.

The amount of the thickener (f) to be added is preferably from 5 to 2,000 ppm, more preferably from 25 to 900 ppm, per part by weight of the monomer. When the content is less than 5 ppm, the effect of improving the particle size distribution of the PVC resin is low because the viscosity is low, and when it exceeds 2000 ppm, a strong skin layer is formed on the surface of the PVC resin, so that the chlorination characteristics afterwards become poor, Also, the gelling properties are not improved.

In the present invention, the shape and structure of the polymerization vessel (pressure-resistant autoclave) used are not particularly limited, and a conventionally known polymerization vessel is used. Examples of the stirring blade include a Faudler blade, a paddle blade, a turbine blade, a fan turbine blade, and a blue margin blade, and among these, the Faudler blade is preferable. The above stirring blade and baffle plate
There is no particular limitation on the combination with.

In the suspension polymerization method of the present invention, the method of adding a suspension dispersant, an emulsifier, a chain transfer agent, a water-soluble thickener, a monomer such as vinyl chloride and the like is carried out by a conventionally known method. Depending on the polymerization conditions, a polymerization regulator, an antistatic agent, a cross-linking agent, a stabilizer, a filler, a scale inhibitor, a pH regulator, and the like may be appropriately added. In addition, the addition can be carried out at once or in a range not departing from the gist of the present invention, and may be intermittent dropping or continuous addition.

In the method for producing a chlorinated vinyl chloride resin of the present invention, the vinyl chloride resin obtained by the above production method is chlorinated. The method for chlorinating the vinyl chloride resin is not particularly limited, and it can be performed by various conventionally known methods. For example, it can be carried out by bringing the vinyl chloride-based resin into contact with chlorine in a suspended state, dissolved in a solvent or in a solid state. Among the above methods, particularly when chlorinating in a suspended state, chlorine is blown directly into the suspension itself without separating the vinyl chloride resin obtained by suspension polymerization from the aqueous medium. Can be chlorinated.

In the case of chlorination in the above-mentioned suspended state, for example, a method of irradiating the reaction product with light to promote chlorination in a photoreactive manner, or exchanging heat with resin to excite the chlorination and chlorination. Can be carried out by a method that promotes The light source used in the case of chlorination by light energy is not particularly limited, and includes, for example, ultraviolet light; visible light such as a mercury lamp, arc lamp, incandescent lamp, fluorescent lamp, and carpon arc lamp; Is effective. The ripening method in the case of chlorination by heat energy is not particularly limited, and examples thereof include an outer jacket method from the reactor wall, an inner jacket method, a steam blowing method, and the like. The inner jacket method is effective.

As the above-mentioned chlorination reaction accelerating method, more preferably, a method of promoting the chlorination by exciting a resin bond or chlorine by heat energy or the like is suitable. In order to achieve uniform chlorination, it is necessary to achieve uniform chlorination reaction at the same time as uniform diffusion of chlorine. Although the heat energy acts uniformly inside the particles, the energy of light irradiation is limited to the surface of the resin particles, so that the chlorination reaction inevitably increases on the surface of the resin particles. Therefore, thermal chlorination is preferred to realize uniform chlorination in diffusion and reaction.

A small amount of ketones such as acetone and methyl ethyl ketone may be added to the aqueous medium used for chlorination in the above suspended state.
A small amount of a chlorinated solvent such as hydrochloric acid, trichloroethylene, carbon tetrachloride and the like may be added. In the chlorination step, the chlorine content of the obtained chlorinated vinyl chloride resin is
It is preferable to adjust so as to be 60 to 72% by weight. More preferably, it is 63 to 70% by weight.

The present invention 2 is a method for producing a vinyl chloride resin used for the chlorinated vinyl chloride resin of the present invention 1. The method for producing the vinyl chloride-based resin of the second invention has already been described above.

[0059]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 Preparation of PVC resin Polymerizer with internal volume of 100 liter (pressure-resistant autoclave)
500 kg of partially saponified polyvinyl acetate (hereinafter also referred to as PVA; average saponification degree of 72 mol% and polymerization degree of 700) with respect to 40 kg of deionized water and vinyl chloride monomer by weight.
ppm, sorbitan monolaurate 1200 ppm, lauric acid 1200 ppm, polyacrylamide (20
° C at 1 atm and a 0.1% by weight aqueous solution having a Brookfield viscosity of 51 cps), 100 ppm, and α
-500 ppm of walnut peroxy neodecanoate were introduced. Next, after degassing the inside of the polymerization vessel to 45 mmHg, 40 kg of a vinyl chloride monomer was charged and stirring was started.

The average degree of polymerization A of the target PVC resin is 1
000, the polymerization temperature B is 5 in the above formula (1).
7.5 ° C., which is 12 ° C. lower than this temperature, that is,
It was decided to carry out at a polymerization temperature of 45.5 ° C. The temperature of the polymerization vessel was raised to 45.5 ° C. to start polymerization, and this temperature was maintained until the completion of the polymerization reaction. When the polymerization conversion reached 10% after the start of the reaction, 340 ppm of dodecyl mercaptan as a chain transfer agent was added dropwise over about 10 minutes while intermittently dropping. The reaction was terminated when the polymerization conversion reached 90%,
After recovering the unreacted monomer in the polymerization vessel, the polymer was taken out of the system in a slurry state, and dehydrated and dried to obtain a PVC resin. The BET surface area of this resin was 3.5 m ² / g. When the skin-free ratio was measured by SEM photograph observation, almost no skin layer was observed, and it was 99%.
The polymerization degree was 1,040. In addition, the measurement of the BET specific surface area, the measurement of the skin-free rate, and the measurement of the degree of polymerization,
It carried out by the following method.

Preparation of CPVC Resin 140 kg of deionized water and 35 kg of the above-obtained PVC resin are put into a 250-liter glass-lined reaction tank, and stirred to disperse the PVC resin in water. Warmed and maintained at 110 ° C. Next, 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 to chlorinate the PVC resin. 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 generated CPVC resin reaches 69.0% by weight, the supply of chlorine gas is stopped. Then, the chlorination reaction was completed. Further, nitrogen gas was blown into the tank to remove unreacted chlorine. The obtained resin was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdery CPVC resin. Obtained C
The chlorine content of the PVC resin was 69.0% by weight.

Example 2 Preparation of a PVC resin was carried out in the same manner as in Example 1 except for the substances and addition amounts shown in Table 1. For the preparation of the CPVC resin, a chlorination reaction was carried out by heat energy excitation as in Example 1.

Example 3 Preparation of a PVC resin was carried out in the same manner as in Example 1 except for the substances and addition amounts shown in Table 1. CPVC resin preparation
The procedure was performed as follows.

Preparation of CPVC Resin 140 kg of deionized water and 35 kg of the PVC resin obtained above were placed in a glass-lined reaction tank having an internal volume of 250 liters, and stirred to disperse the PVC resin in water. Thereafter, the reaction tank was heated. The inside of the tank was kept at 70 ° C. Next, nitrogen gas was blown into the reaction tank, and the inside of the tank was replaced with nitrogen gas.
Next, chlorine gas was blown into the reaction tank, and the PVC resin was chlorinated while irradiating the inside of the tank with ultraviolet rays using 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 generated CPVC resin reaches 69.0% by weight, the supply of the chlorinated gas is started. The operation was stopped and the chlorination reaction was terminated. Further, nitrogen gas was blown into the tank to remove unreacted chlorine. The obtained resin was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdery CPVC resin. Obtained C
The chlorine content of the PVC resin was 69.0% by weight.

Example 4 For the preparation of a PVC resin, polymerization was carried out without using an emulsifier, a fatty acid and a thickener, and a chain transfer agent was added. The same operation as in Example 1 was carried out except for the substances and addition amounts shown in Table 1. The preparation of the CPVC resin of Example 4 was carried out in the same manner as in Example 3 except that shown in Table 1.

Example 5 For the preparation of a PVC resin, polymerization was carried out without using an emulsifier, a fatty acid and a thickener, and a chain transfer agent was added. The same operation as in Example 1 was carried out except for the substances and addition amounts shown in Table 1. For the preparation of the CPVC resin, a chlorination reaction was carried out by heat energy excitation as in Example 1.

Comparative Example 1 For the preparation of a PVC resin, polymerization was carried out without using an emulsifier, a fatty acid and a thickener, and a chain transfer agent was added. The same operation as in Example 1 was carried out except for the substances and addition amounts shown in Table 2. The preparation of the CPVC resin was carried out in the same manner as in Example 3 except that shown in Table 2.

Comparative Examples 2 to 4 For preparing a PVC resin, polymerization was carried out without using an emulsifier, a fatty acid and a thickener, and a chain transfer agent was added under each condition. Example 1 was repeated except for the substances and addition amounts shown in Table 2.
Was performed in the same manner as described above. For the preparation of the CPVC resin, a chlorination reaction was carried out by heat energy excitation as in Example 1.

Comparative Examples 5 and 6 The preparation of the PVC resin was carried out in the same manner as in Example 1 except for the substances and the addition amounts shown in Table 2. For the preparation of the CPVC resin, a chlorination reaction was carried out by heat energy excitation as in Example 1.

Comparative Example 7 For the preparation of a PVC resin, polymerization was carried out without using an emulsifier, a fatty acid and a thickener, and a chain transfer agent was added. The same operation as in Example 1 was carried out except for the substances and addition amounts shown in Table 2. The preparation of the CPVC resin was carried out in the same manner as in Example 3 except that shown in Table 2.

The PVC resin and the CPVC resin obtained in the above Examples and Comparative Examples were measured and evaluated for performance by the following methods, and the results are shown in Tables 1 and 2. In the table, dodecyl mercaptan is used as the chain transfer agent I, 2-mercaptoethanol is used as the chain transfer agent II, α-walmi peroxy neodecanoate is used as the polymerization initiator III, and t-butyl peroxy neo is used as the polymerization initiator IV. Decanoate and azobis (4-methoxy-dimethylvaleronitrile) were used as the polymerization initiator V.

The particle size distribution is represented by the ratio of 42 mesh ON products, 7.7% by weight in Comparative Example 2, and 2.75% in Comparative Example 5.
4% by weight and all others were 0.01% by weight.

(1) Measurement of Degree of Polymerization The average degree of polymerization was measured from the specific viscosity in accordance with JIS K 6721 (Testing method for vinyl chloride resin).

(2) Evaluation of surface condition (skin-free ratio) The PVC resin particles obtained in Examples and Comparative Examples were subjected to scanning electron microscope (FE-SEM S-420, manufactured by Hitachi, Ltd.).
According to 0), an image was taken at an acceleration voltage of 2 kV and a magnification of 130, and the contour of the particles, the skin portion, and the portion where the skin did not exist (the portion where the primary particles were exposed, hereinafter referred to as a skin-free portion). Copy to racing paper (or OHP sheet). Next, tracing paper (or O
HP sheet) with an image analysis device (Pierce, PIAS-
Introduced in III), image analysis was performed, the particle area and skin-free area were calculated, and the skin-free rate was determined according to the following equation. Skin-free rate = (skin-free area / particle area) x 1
00

(3) Measurement of BET specific surface area About 2 g of a measurement sample was put into a sample tube, and 7
After degassing the sample for 3 hours at 0 ° C., the sample weight was measured accurately. The sample after the pretreatment was attached to a measuring section (40 ° C. constant temperature bath) to start measurement. After the measurement, a BET plot was performed from the data on the adsorption side of the adsorption isotherm to calculate the specific surface area. In addition, a specific surface measuring device “BELSORP 28SA” (manufactured by Nippon Bell Co., Ltd.) was used as a measuring device, and nitrogen gas was used as a measuring gas.

(4) Processability (Measurement of Gelation Temperature) Using “Rheocord 90” manufactured by Haake, 55 g of the following resin composition was heated at a rotation speed of 40 rpm and a temperature of 150 ° C.
Kneading was carried out while increasing the temperature at a rate of 5 ° C./min from the temperature, and the temperature at which the kneading torque was maximized was measured. The resin composition used was composed of 3 parts by weight of tribasic lead sulfate, 1 part by weight of dibasic lead stearate, and 10 parts by weight of MBS resin based on 100 parts by weight of CPVC resin.

(5) Thermal Stability Test The above resin composition was supplied to a kneader comprising two 8-inch rolls and kneaded at a roll surface temperature of 205 ° C., and the kneaded material was wound around a roll every 30 seconds. Wound CPVC
While turning over the resin sheet, a small amount of the sheet was cut out every three minutes, the degree of coloring of the sheet was compared, and the thermal stability was determined by the time when the sheet turned black-brown.

(6) Vicat softening temperature A 5 mm thick CPVC resin sheet prepared in the above thermal stability test was cut into 15 mm squares to obtain a measurement sample.
It measured based on JISK7206 (weight 1.0kgf).

[0080]

[Table 1]

[0081]

[Table 2]

[0082]

As described above, the method for producing a chlorinated vinyl chloride resin of the present invention has the above-mentioned constitution, and therefore, it is possible to provide a chlorinated vinyl chloride resin excellent in gelation performance and heat resistance.

Claims (4)

[Claims] 1. A method for producing a chlorinated vinyl chloride-based resin obtained by chlorinating a vinyl chloride-based resin, wherein the vinyl chloride-based resin is produced in the presence of a dispersant and an oil-soluble polymerization initiator.
It is obtained by subjecting a monomer to suspension polymerization, and the suspension polymerization is carried out according to the following formula (1).
Polymerization is started at a temperature 5 to 20 ° C. lower than the polymerization temperature B (° C.) determined from the above, and when the polymerization conversion is 3 to 20%, the polymerization is carried out by adding a chain transfer agent to obtain the vinyl chloride. The method for producing a chlorinated vinyl chloride resin, wherein the degree of polymerization of the resin is the average degree of polymerization A ± 100. B = 0.016A−41.44LN (A) +327.7 (1) (where A represents the average degree of polymerization, B represents the polymerization temperature (° C.), and LN (A) has e as the bottom. Represents the natural logarithm.) 2. The dispersant is at least one selected from the group consisting of partially saponified polyvinyl acetate (a) and a cellulose derivative (b). In the suspension polymerization, an HLB value is determined in an aqueous medium. Is at least one emulsifier selected from the group consisting of sorbitan higher fatty acid ester (c) having 3 to 10 and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and normal temperature and normal pressure 2. The method for producing a chlorinated vinyl chloride resin according to claim 1, wherein the 0.1% by weight aqueous solution is subjected to the presence of a thickener (f) having a Brookfield's viscosity of 10 to 200 cps. 3. A method for producing a vinyl chloride resin by subjecting a monomer to suspension polymerization in the presence of a dispersant and an oil-soluble polymerization initiator, wherein the suspension polymerization comprises the following formula (1) From the polymerization temperature B (° C.) determined from the average degree of polymerization A by 5 to 2
The polymerization is started at a temperature lower by 0 ° C., and the polymerization conversion rate is 3 to 2
When 0%, the reaction is carried out by adding a chain transfer agent, and the degree of polymerization of the obtained vinyl chloride resin is the above average degree of polymerization A ± 100. Method. B = 0.016A−41.44LN (A) +327.7 (1) (where A represents the average degree of polymerization, B represents the polymerization temperature (° C.), and LN (A) has e as the bottom. Represents the natural logarithm.) 4. The dispersant is at least one selected from the group consisting of partially saponified polyvinyl acetate (a) and a cellulose derivative (b), and the suspension polymerization further comprises an HLB value in an aqueous medium. Is at least one emulsifier selected from the group consisting of sorbitan higher fatty acid ester (c) having 3 to 10 and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and normal temperature and normal pressure The method for producing a vinyl chloride resin according to claim 3, wherein the 0.1% by weight aqueous solution is subjected to the presence of a thickener (f) having a Brookfield's viscosity of 10 to 200 cps.