JPH11209425A - Production of chlorinated vinyl chloride resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a chlorinated vinyl chloride resin excellent in both gelling performances and heat resistance. SOLUTION: There is provided a process for producing a chlorinated vinyl chloride resin by chlorinating a vinyl chloride resin, which process comprises: starting the suspension polymerization of a vinyl chloride monomer at a specified polymerization temperature in the presence of a dispersant and an oil- soluble polymerization initiator in an aqueous medium; raising the temperature after the conversion reaches 60 wt.%; continuing the polymerization at a temperature higher than the above polymerization temperature by 5-25 deg.C to produce a vinyl chloride resin; and chlorinating the obtained vinyl chloride resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a chlorinated vinyl chloride resin.

[0002]

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

[0003] PVC 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 has a heat deformation temperature of 20 to 40 ° C than PVC. Therefore, it can be used for hot water, and is suitably used for heat-resistant pipes, heat-resistant joints, heat-resistant valves, and the like.

However, since CPVC has a high heat deformation temperature, a high temperature and a strong shearing force are required for gelling at the time of molding processability, and it tends to be decomposed and colored during molding. Therefore, CPVC is often produced in a narrow molding process width and in an insufficiently gelled state,
The performance of the material was not fully demonstrated. 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. Discloses a method of chlorinating PVC composed of aggregates composed of basic particles of about 1 μm (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 of the polymerization vessel 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.
There is disclosed a method of blending VC and PVC so as to be within a specific viscosity range to obtain high heat resistance (improvement by resin blending). However, in this method,
It is possible to expect improvement of heat resistance of about 3-4 ° C in Vicat value and slight improvement of gelation performance by improvement of melt viscosity. Did not achieve.

[0007] JP-A-6-128320 discloses PV
As a chlorination method of C, a chlorination method by two steps (two-step post-chlorination method) is disclosed. This method
By increasing the chlorine content to 70-75% by weight,
It is intended to obtain a CPVC having high heat resistance (an improvement proposal by a high chlorination method). However, in this method, although high heat resistance can be expected according to the chlorine content, no means has been shown for preventing the deterioration of the gelation performance predicted by high chlorination,
High heat resistance 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 diameter and the porosity of PVC 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 is improved, but the gelation performance is not 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 by PVC having a large surface area of a specific surface area of 1.3 to 8 m ² / g in terms of a specific surface area by a 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 a molded article requiring higher heat resistance. Japanese Patent Application Laid-Open No. 9-132612 focuses on the surface properties of resin particles (skin layer) and proposes a method of chlorinating PVC in which the skin layer is substantially absent or the skin layer is thin. Japanese Unexamined Patent Publication No. Hei 9-11871
As in the case of JP-A No. 3 (1993), improvement in both properties of heat resistance and gelling is observed, but it was not satisfactory for molded articles requiring further high 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). ) Is disclosed. The PVC to be subjected to chlorination is prepared by subjecting PVC obtained by this method to PV
When used as C, although an improvement in moldability is observed, there are relatively high and low polymerization degrees in the PVC particles, and high heat resistance is obtained even when chlorinated by a known chlorination method. There was no problem.

Japanese Patent Application Laid-Open No. 7-188315 discloses a method for producing PVC 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 the PVC finally has a desired degree of polymerization. However, while the polymerization temperature is continuously changed, the chain transfer agent has a polymerization conversion rate at a specific time. It is added all at once. When PVC produced by this method is used as the PVC to be subjected to chlorination, the moldability is improved, but the above-mentioned JP-A-Hei-5 is used.
JP-A-7-192411 and JP-A-57-1951
Similar to the reason in JP-A-07-07, there is a problem that high heat resistance cannot be obtained even if chlorination is performed by a known chlorination method.

JP-A-59-168008, JP-A-59-96152, JP-A-60-72906, JP-A-61-126112, and JP-A-8-168112
No. 53503 discloses a method including a step of raising the polymerization temperature in the polymerization process. JP 5
In Japanese Patent Application Laid-Open No. 9-168008, the polymerization conversion rate is 5 at the latest.
The purpose is to obtain a PVC having a high bulk specific gravity by increasing the temperature by 5 ° C. or more until the weight becomes 0% by weight and further adding a monomer before the internal pressure of the polymerization vessel is lowered. JP-A-59-96152 aims to improve the moldability by performing polymerization in a plurality of stages and gradually reducing the degree of polymerization. Japanese Patent Application Laid-Open No. Sho 60-72906 proposes a method for producing PVC suitable for injection molding by adding a chain transfer agent during a polymerization conversion of 20 to 70% by weight and then increasing the temperature. Japanese Patent Application Laid-Open No. 61-126112 proposes to improve polymerization productivity and molding workability by performing polymerization while raising the temperature for 50% or more of the polymerization period. JP-A-8-53503 proposes to increase the temperature in the presence of an antioxidant to improve polymerization productivity.

However, in any case, the degree of polymerization in the resin particles is not considered as the CPVC in consideration of the chlorination reaction, nor is there any means disclosed for resuspension polymerization in the presence of the CPVC. There is a problem that heat resistance and moldability (gelling property) cannot be obtained.

[0014]

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 PVC, thereby controlling the distribution of chlorination to improve the gelation performance. An object of the present invention is to provide a method for producing CPVC having excellent heat resistance. Also, if CPVC is P
An object of the present invention is to provide a method for producing a CPVC having excellent gelling performance and heat resistance by improving the processability of the CPVC by coating with VC.

[0015]

The invention according to claim 1 (hereinafter referred to as the first invention) is a method for producing a CP obtained by chlorinating PVC.
A method for producing VC, comprising a vinyl chloride-based monomer (hereinafter, referred to as
VCM) in the presence of a dispersant and an oil-soluble polymerization initiator in an aqueous medium at a predetermined polymerization temperature to initiate suspension polymerization, and after the polymerization conversion reaches 60% by weight, the temperature is increased. The polymerization is continued at a temperature 5 to 25 ° C. higher than the polymerization temperature,
It is characterized by producing VC and chlorinating the obtained PVC.

The invention according to claim 2 (hereinafter referred to as the second invention) is characterized in that a partially saponified polyvinyl acetate (a) and a cellulose derivative (b) are added to a VCM in the presence of an oil-soluble polymerization initiator.
At least one dispersant selected from the group consisting of
At least one emulsifier selected from the group consisting of a sorbitan higher fatty acid ester (c) having an LB value of 3 to 10 and an anionic emulsifier (d); a higher fatty acid (e) having 8 to 25 carbon atoms; A 0.1% by weight aqueous solution at normal pressure is added with a thickener (f) having a Brookfield's viscosity of 10 to 200 cP, suspension polymerization is started at a predetermined polymerization temperature in an aqueous medium, and the polymerization conversion is 60%. Starting the heating after reaching the weight%, completing the heating before the polymerization conversion rate reaches 85% by weight, and continuing the polymerization at a temperature higher by 5 to 25 ° C. than the polymerization temperature to produce PVC. It is characterized by.

According to a third aspect of the present invention (hereinafter referred to as a third aspect), after the PVC of the first or second aspect is suspended in an aqueous medium, liquid chlorine or gaseous chlorine is introduced into the reactor. In the presence of at least one oil-soluble initiator selected from the group consisting of 20 to 60 ° C.
The chlorination reaction is carried out at a reaction temperature of 20 to 60 ° C.

The invention according to claim 4 (hereinafter, referred to as a fourth invention) is characterized in that a CP obtained by polymerizing VCM on the surface of a raw material CPVC is used.
When producing VC, the raw material CPVC having a chlorine content of 66 to 75% by weight is made into a suspended state in the presence of VCM, a dispersant and an oil-soluble initiator, and the raw material CPVC1 to be charged at the time of polymerization is used.
20 to 50 parts by weight of VCM with respect to 00 parts by weight, and suspension polymerization is performed until the polymerization conversion of VCM becomes 5 to 15% by weight.

The invention according to claim 5 (hereinafter referred to as the fifth invention) is characterized in that the raw material CPVC according to claim 4 has an average porosity of 2
8 to 39% by volume and an average particle size of 70 to 250.
It is characterized by using a raw material CPVC of μm.

[0020] The invention according to claim 6 (hereinafter referred to as the sixth invention) is characterized in that, in the presence of the raw material CPVC and the oil-soluble initiator,
CM contains at least one dispersant selected from the group consisting of partially saponified polyvinyl acetate (a) and cellulose derivative (b), a sorbitan higher fatty acid ester (c) having an HLB value of 3 to 10, and an anionic emulsifier ( d) at least one emulsifier selected from the group consisting of:
25 fatty acids (e) and a thickener (f) having a Brookfield viscosity of 10 to 200 cP in a 0.1% by weight aqueous solution at normal temperature and pressure are added, and suspended in an aqueous medium at a predetermined polymerization temperature. The method for producing a CPVC according to claim 4 or 5, wherein the suspension polymerization is started, and the suspension polymerization is carried out until the average degree of polymerization of the PVC coating the raw material CPVC becomes ± 200 of the average degree of polymerization of the raw material CPVC. Hereinafter, the present invention will be described in detail.

The present invention relates to a method for producing a PVC,
Is a method for producing CPVC obtained by chlorinating a compound. In addition, the obtained CPVC is charged into a polymerization vessel, and suspension polymerization is carried out in an aqueous medium in the coexistence state of a VCM, a dispersant, and an oil-soluble initiator. First, a method for manufacturing PVC will be described. In the present invention, PVC means a homopolymer of VCM and a copolymer of VCM at 50% by weight or more and a monomer copolymerizable therewith.

The monomer copolymerizable with the above-mentioned VCM is not particularly restricted but includes, for example, alkyl vinyl esters such as vinyl acetate; α-monoolefins such as ethylene and propylene; methyl (meth) acrylate, ethyl ( Alkyl (meth) acrylates such as meth) acrylate and octyl acrylate; alkyl vinyl ethers; maleimides, vinylidene chloride, styrene, and the like;
Two or more of these may be used in combination.

The oil-soluble polymerization initiator is not particularly limited, and a known radical initiator generally used for PVC polymerization 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-2-
Perester compounds such as peroxy-2-neodecanoate; diisopropyl peroxydicarbonate, di-
2-ethylhexyl peroxydicarbonate, di-2
-Percarbonate compounds such as ethoxyethyl peroxydicarbonate, dimethoxyisopropylperoxydicarbonate; decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, 2,
Peroxide compounds such as 4-dichlorobenzoyl peroxide, p-menthane hydroperoxide, 3,5,5-trimethylhexanoyl peroxide and isobutyl peroxide; α, α'-azobisisobutyronitrile, α, α ' -Azobis (dimethylvaleronitrile),
Examples include azo compounds such as α, α′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and two or more of them may be used in combination.

The dispersant is not particularly limited, and a known dispersant generally used for polymerization of PVC 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.

The amount of the dispersant added is preferably from 100 to 30,000 ppm based on VCM parts by weight.

Generally, in the production of PVC, PV
It is known that the average degree of polymerization or molecular weight of C is generally determined by the polymerization temperature during the polymerization of VCM. This is VC
This is because, in the radical polymerization of M, a polymer is highly likely to be generated by the chain transfer of the radical to the VCM, and the chain transfer constant of the radical to the VCM is a function of the temperature (“polychlorinated”). Vinyl Resins-Basics and Applications ”, p. 65 (edited by Kinki Chemical Association Vinyl Subcommittee, published by Nikkan Kogyo Shimbun, 1988).

For example, when the desired average degree of polymerization is about 100
The production of zero PVC would be carried out at a polymerization temperature of about 57 ° C. Similarly, those having an average degree of polymerization of about 1400 are about 50 ° C, those having an average degree of polymerization of about 800 are about 64 ° C,
Those having an average degree of polymerization of about 500 will be conducted at a polymerization temperature of about 78 ° C.

On the other hand, the crystallinity of PVC is such that the polymerization temperature is about 5
It is reported that the content is about 8% at 7 ° C. and 1.5% when the polymerization temperature is increased by 10 ° C. (“Polyvinyl chloride resin-basics and applications”, page 70 (Kinki Chemical Association Vinyl Subcommittee). Ed., Published by the Nikkan Kogyo Shimbun, 1988)).

In the first invention, in consideration of the relationship between the average polymerization degree and the polymerization temperature and the relationship between the crystallinity and the polymerization temperature, the surface of the PVC is coated with a relatively low polymerization degree or a PVC having a low crystallinity. The process is realized by raising the temperature during the polymerization. The lowering of the degree of polymerization can be achieved at the same time by lowering the crystallization by polymerization at a high temperature, so that the moldability can be improved. Further, the low crystallization promotes chlorination near the surface of the PVC particles. Usually, since chlorination near the surface of PVC particles proceeds from inside the particles, the surface tends to be hard and the processability is deteriorated. In the present invention, chlorination accompanying low crystallization proceeds, but the number of crystals is small. Therefore, the tendency to harden is alleviated, and deterioration of workability can be suppressed.

The method for producing PVC according to the first invention relates to a method for producing suspension polymerization in an aqueous medium. The method comprises the steps of starting polymerization in the presence of a VCM, a dispersant, and an oil-soluble polymerization initiator and then raising the polymerization temperature. In the above, the temperature is raised by 5 to 25 ° C. higher than the polymerization temperature, and the polymerization conversion rate is higher than 60% by weight.

The heating temperature is 5 to 25 ° C. higher than the polymerization temperature.
The range is limited to a high range, and preferably 10 to 20 ° C. If the temperature rise temperature is less than 5 ° C., the effect of lowering the degree of polymerization and the degree of crystallinity is low, and the effect of improving moldability is not sufficient. Heating temperature is 2
When the temperature exceeds 5 ° C., the heat stability is deteriorated due to an excessive temperature raising operation in a state where the VCM is small, and the initial coloring is not good. Further, since the degree of polymerization is lower than a predetermined degree of polymerization, it is not preferable for applications requiring mechanical strength.

The temperature rising time is limited after the polymerization conversion rate exceeds 60% by weight. When the polymerization conversion rate rises from less than 60% by weight, the polymerization conversion rate is further increased, and the reaction rate is increased when the VCM amount is smaller, so that an abnormal structure such as a branched structure is easily generated, and heat stability is obtained. The properties and initial coloring deteriorate.

The average degree of polymerization of the PVC produced as described above is determined by the physical properties and performance required for the intended use of the PVC, and the average degree of polymerization to be carried out in the present invention is 400 to 2500. preferable. In the present invention, since the polymerization conditions are to lower the degree of polymerization during the late to late stages of polymerization, in order to ensure mechanical strength, if it is necessary to strictly set the average degree of polymerization, the polymerization is performed by assuming the average degree of polymerization in advance. The temperature, the temperature rise temperature, and the temperature rise time are set.

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. Also, the stirring blade
Examples include a Faudler blade, a paddle blade, a turbine blade, a fan turbine blade, and a bull margin blade, and among them, the Faudler blade is preferable. The combination of the stirring blade and the baffle is not particularly limited.

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.

According to the second invention, the effect of improving the processability of the chlorinated CPVC of the obtained PVC is synergistically increased by the method for producing PVC having a thin skin layer and the setting of the completion time of the temperature rise during polymerization. did.

In the method for producing PVC of the second invention, the dispersant is preferably at least one selected from the group consisting of partially saponified polyvinyl acetate (a) and cellulose derivative (b). Partially saponified polyvinyl acetate (a)
Alternatively, various dispersants selected from the above-mentioned cellulose derivatives (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
VC has many 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 particles does not increase. Therefore, the reaction rate during the subsequent gel chlorination does not increase sufficiently, and the resulting CP
The gelation properties of VC do not improve. More preferably, 70
~ 85 mol%.

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

The amount of the partially saponified polyvinyl acetate (a) to be added is preferably 150 to 2000 ppm based on VCM. If the amount is less than 150 ppm, the oil droplets of VCM become unstable, so that the PVC tends to be block-shaped. 2000
When the content exceeds ppm, the skin layer on the surface of the PVC particles becomes thick, and it is not possible to expect improvement in chlorination characteristics later, and the moldability is not improved.

Examples of the cellulose derivative (b) include methylcellulose, ethylcellulose, hydroxypropylmethylcellulose and hydroxyethylcellulose. The cellulose derivative (b) is added in an amount of 150 to 2000 ppm based on VCM. If it is less than 150 ppm, the oil droplets of the VCM become unstable, so that the PVC tends to become blocky,
If it exceeds 0 ppm, the skin layer on the surface of the PVC particles becomes thick, and it is not possible to improve the chlorination characteristics later, and the moldability is not improved.

The method for producing PVC of the second invention further comprises
At least one emulsifier selected from the group consisting of sorbitan higher fatty acid ester (c) having an LB value of 3 to 10 and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and room temperature 0.1% by weight at normal pressure
Is preferably carried out in the presence of a thickener (f) having a Brookfield's viscosity of 10 to 200 cps.

The above sorbitan higher fatty acid ester (c)
Is preferably 3 to 10. If less than 3,
Since the lipophilicity is strong, the emulsifying and dispersing ability of the monomer in water is low, and the particle size distribution of the obtained PVC is wide including coarse particles. If it exceeds 10, the oil droplets of the monomer being polymerized become unstable due to high hydrophilicity, and the aggregation of VCM particles tends to occur, and the PVC becomes an aggregate of block-like and coarse particles. More 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 Examples thereof include sorbitan saturated higher fatty acid esters such as stearate and unsaturated higher fatty acid esters, and these may be used in combination of two or more.

The above sorbitan higher fatty acid ester (c)
Is added in an amount of 500 to 5000 ppm based on VCM.
And more preferably 800 to 2500 ppm. If it is less than 500 ppm, the skin layer is formed thick, lacks porosity, and molding processability becomes poor. 50
If it exceeds 00 ppm, the particle size distribution is wide and the resin scale adheres to the inner wall of the polymerization vessel.

Examples of the anionic emulsifier (d) include fatty acid salts such as sodium stearate soap; alkyl sulfate esters 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;
Naphthalenesulfonic acid formalin condensate; special polycarboxylic acid type polymer surfactant; polyoxyethylene alkyl phosphate; reactive surfactant; and the like, and two or more of these may be used in combination.

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 VCM. If the amount is less than 1 ppm, the skin layer of the PVC particles is formed to be thick, the porosity is insufficient, and the BET specific surface area is reduced. If it exceeds 3000 ppm, the particle size distribution becomes wide, a large amount of resin scale adheres to the inner wall of the polymerization vessel, and sometimes PVC particles are blocked,
PVC 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.

The method for producing PVC of the second invention further uses a higher fatty acid (e) having 8 to 25 carbon atoms. As the higher fatty acid (e) having 8 to 25 carbon atoms, the effect is not reduced by the degree of unsaturation and branching of the main chain, and the higher fatty acid (e) has 8 carbon atoms.
Although it may be any one of from 25 to 25, a linear saturated fatty acid is preferable. 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. 2 carbon atoms
If it exceeds 5, the melting point of the higher fatty acid increases, so that PV
Even at the temperature of the forming process of C, it is difficult to exhibit the gelation promoting effect.

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 addition amount of the higher fatty acid (e) having 8 to 25 carbon atoms is based on parts by weight of VCM.
300-20,000 ppm is preferred.

In the method for producing PVC according to the second aspect of the present invention,
0.1% by weight aqueous solution at normal temperature and pressure is 10 to 200%
Thickener having Brookfields viscosity of cps (f)
Is used. 0.1% by weight aqueous solution at normal temperature and pressure
Examples of the thickener (f) having a Brookfield viscosity of 0 to 200 cps include polyethylene oxide, polyvinylpyrrolidone, polyacrylamide, polyacrylamide copolymer, crosslinked (meth) acrylic resin, methylcellulose calcium, and starch glycol. Sodium acid, sodium starch phosphate, sodium alginate, propylene glycol alginate, sodium carboxymethylcellulose, calcium carboxymethylcellulose, etc., may be used in combination of two or more.

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 preferably has an average molecular weight of 8,000,000 to 14,000,000. 0.1 to 14 million polyacrylamide having an average molecular weight of 0.1
When converted to a weight percent aqueous solution, Brookfields viscosity is 51%.
cps.

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

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

As described in the first invention, in the method for producing PVC of the second invention, after the start of the heating, the heating is completed before the polymerization conversion rate reaches 85% by weight, and the polymerization is carried out while maintaining the temperature. It is preferred to do so. When the temperature rise is completed after 85% by weight,
Since the time for maintaining the temperature at constant temperature until the completion of the polymerization is short, the particle size distribution of the resin particles may be widened.

In the method for producing CPVC of the second invention, PVC obtained by the above production method is chlorinated. The method for chlorinating PVC is not particularly limited, and can be performed by various conventionally known methods. For example, it can be carried out by bringing the above PVC in a suspended state, dissolved in a solvent or in a solid state into contact with chlorine. Among the above methods, especially when chlorinating in a suspended state, the PVC obtained by suspension polymerization may be dried and then resuspended in an aqueous medium. A suspension from which substances undesirable for the chlorination reaction such as hydrochloric acid have been removed may be used. That is, chlorination can be performed by blowing chlorine directly into the suspension itself without separating the PVC obtained by the suspension polymerization from the aqueous medium.

In the case of chlorination in the above-mentioned suspended state, for example, a method of irradiating the reaction product with light to accelerate chlorination in a photoreactive manner, or exchanging heat with resin to excite the chlorinating of the resin 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 thermal energy or the like is suitable. In order to achieve uniform chlorination, it is preferable to achieve uniform chlorination reaction simultaneously with 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-mentioned suspended state.
A small amount of a chlorinated solvent such as hydrochloric acid, trichloroethylene, carbon tetrachloride and the like may be added. As the material of the chlorination reactor to be used, a commonly used one such as a stainless steel reactor having a glass lining and a titanium reactor can be applied. The amount of the aqueous medium to be charged into the reactor is not particularly limited, but usually, it is preferable to charge 2 to 10 (weight times) the aqueous medium with respect to 1 weight of PVC.

In the above chlorination step, the obtained C
It is preferable to adjust the chlorine content of PVC to be 60 to 72% by weight. More preferably, 63 to 70
% By weight. When the chlorine content is less than 60% by weight, the heat resistance of the obtained CPVC is poor, and when it exceeds 72% by weight, heat resistance is obtained, but gelation property is deteriorated and molding of heat-resistant molded articles is difficult. Disadvantageous.

The third invention includes a proposal to select a reaction initiator for the PVC obtained in the first or second invention to efficiently promote a chlorination reaction at a low temperature,
By the organic combination of these inventions, the resulting C
PVC has high heat resistance and good moldability.

In the chlorination reaction of the third invention, after the above-mentioned PVC is suspended in an aqueous medium, liquid chlorine or gaseous chlorine is introduced into the reactor, and the reaction temperature is 20 to 60 ° C. A method for producing a chlorinated vinyl chloride-based resin, characterized in that a chlorination reaction is advanced by using a soluble initiator, wherein a substance whose 10-hour half-life of the oil-soluble initiator is selected from 20 to 60 ° C. This is a method for producing a CPVC whose main point is to use it.

In the chlorination of the third invention, after a PVC is suspended in an aqueous medium, a chlorine source such as liquid chlorine or gaseous chlorine is introduced into the reactor. Liquid chlorine is introduced. This is efficient in terms of the process. In order to adjust the pressure during the reaction and to supply chlorine along with the progress of the chlorination reaction, gaseous chlorine can be blown as appropriate in addition to liquid chlorine.

The chlorination reaction temperature is preferably from 20 to 60 ° C, more preferably from 25 to 40 ° C. Reaction temperature 20
If the temperature is lower than ℃, the chlorination reaction speed becomes slow, the reaction takes a long time, and the chlorination outside the particles further proceeds, so that the chlorination uniformity is impaired, and the particle surface in the first invention or the second invention is reduced. The advantage of low degree of polymerization and low crystallization is impaired, and it is difficult to improve heat resistance. When the reaction temperature exceeds 60 ° C., the amount of chlorine dissolved in the aqueous medium or PVC, which is present in the form of swelling, is reduced, and the chlorine moves into the gas phase, making it difficult for chlorination to proceed uniformly, and reducing heat resistance. Difficult to improve.

The chlorination reaction temperature is generally 40 to 90 ° C. for a photo chlorination reaction using a light energy source such as irradiation with an ultraviolet lamp, and 70 to 90 ° C. for a thermal energy chlorination reaction.
It is customary to carry out at 150 ° C. In the present invention, a chlorination reaction in a relatively low temperature range of 20 to 60 ° C. has been proposed in order to secure an amount of chlorine dissolved in an aqueous medium in order to promote diffusion of chlorine into resin particles. The gauge pressure in the reactor is not particularly limited, but the higher the chlorine pressure, the more easily chlorine penetrates into the PVC particles.
The range of 2 to 2 MPa is preferable. At this temperature, the chlorination reaction rate is slow, but an oil-soluble initiator is used to accelerate the chlorination reaction in which the reaction rate is reduced by low temperature, and its 10-hour half-life temperature is 20 to 60 ° C. A range is selected.

The oil-soluble initiator having a 10-hour half-life temperature of 20 to 60 ° C. is selected from organic peroxide compounds and azo compounds.

Examples of the organic peroxide compound having a 10-hour half-life temperature of 20 to 60 ° C. include t-butyl peroxypivalate (half-life = 56 ° C., the same applies hereinafter), t-hexyl peroxypivalate ( 53 ° C),
t-hexyl neohexanoate (49 ° C.), t-butyl peroxy neodecanoate (47 ° C.), t-hexyl peroxy neodecanoate (45 ° C.), α-cumyl peroxy neohexanoate ( 41 ° C), 2, 4, 4
-Trimethylpentyl-2-peroxy-2-neodecanoate (41 ° C), α-cumylperoxyneodecanoate (38 ° C), 2,4,4-trimethylpentyl-
Perester compounds such as 2-peroxyphenoxyacetate (38 ° C) and acetylcyclohexanesulfonyl (37 ° C);

Di (3-methyl-3-methoxybutyl) peroxydicarbonate (47 ° C.), di (sec-butyl) peroxydicarbonate (45 ° C.), diisopropylperoxydicarbonate (45 ° C.), bis ( 4-
t-butylcyclohexyl) peroxydicarbonate (44 ° C), di-2-ethylhexylperoxydicarbonate (44 ° C), dimethoxyisopropyl peroxydicarbonate (44 ° C), di (3-methoxybutyl) peroxydicarbonate (43 ° C), di-2-ethoxyethylperoxydicarbonate (43 ° C), di-n-propylperoxydicarbonate (41 ° C),
Peroxycarbonate compounds such as dimyristyl peroxydicarbonate (41 ° C.) and diallyl peroxydicarbonate (39 ° C.);

Lauroyl peroxide (60 ° C.),
3,5,5-trimethylhexanoyl peroxide (60 ° C.), o-methylbenzoyl peroxide (5
7 ° C.), diacyl peroxide compounds such as 2,4-dichlorobenzoyl peroxide (54 ° C.) and isobutyryl peroxide (33 ° C.).

The above 10 hour half-life temperature is 20 to 60.
The azo compounds at ℃ are limited to azonitrile compounds, for example, α, α'-azobis (2,4-dimethylvaleronitrile) (51 ° C), α, α'-azobis (2-
Cyclopropylpropionitrile) (42 ° C.), α,
An azo compound such as α′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (30 ° C.) is exemplified.

As a more preferred example of the chlorination reaction catalyst, the oil-soluble initiator having a 10-hour half-life temperature of 30 to 5
An oil-soluble initiator in the range of 0 ° C. may be mentioned, and is selected from the above-mentioned perester compounds, peroxycarbonate compounds, diacyl peroxide compounds and azo compounds.

The amount of the chlorination catalyst added is preferably in the range of 0.001 to 0.5% by weight, more preferably 0.005 to 0.1% by weight, based on PVC (weight).

In the method for producing CPVC according to the fourth invention, a raw material CPVC having a chlorine content of 66 to 75% by weight is suspended in the presence of a VCM, a dispersant, and an oil-soluble initiator, and is charged during polymerization. For 100 parts by weight of raw material CPVC, VC
M20 to 50 parts by weight, and the polymerization conversion rate of VCM is 5
A method for producing a coated CPVC that is 15% by weight.

The raw material CPV obtained in the above chlorination step
The chlorine content of C is limited to 66-75% by weight,
73% by weight is preferred. When the chlorine content is less than 66% by weight, the heat resistance is poor, and when it exceeds 75% by weight, the heat resistance is high, but the gelling property is deteriorated, which is disadvantageous for molding a heat-resistant molded article.

The method of chlorinating PVC is not particularly limited, and it can be carried out by a conventionally known method. Specifically, the method according to the second invention is similarly performed.

[0077] In the chlorination reaction, after the PVC is suspended in an aqueous medium, gaseous chlorine or liquid chlorine is introduced into the reactor, and the reaction temperature is appropriately adjusted within the range of 20 to 140 ° C. As the chlorination reaction catalyst, a method in which hydrogen peroxide or an oil-soluble initiator is used to promote the chlorination reaction is applied.

As the chlorination reaction catalyst, hydrogen peroxide or an oil-soluble initiator can be used, but hydrogen peroxide is preferable. Hydrogen peroxide (water) has a small molecular weight at the time of chlorination, so it spreads throughout the PVC particles and promotes the chlorination reaction. Therefore, chlorination proceeds smoothly within the PVC particles, and a high heat-resistant CPVC is obtained. Can be Further, there is no danger that a decomposition product of the radical product causes a cause of coloring.

The oil-soluble initiator is preferably a substance selected from organic peroxide compounds and azo compounds having a 10-hour half-life of 20 to 130 ° C.
The 10-hour half-life temperature is -30 to the chlorination reaction temperature.
It is preferable to select an oil-soluble initiator so as to be in the range of + 10 ° C.

As the above-mentioned organic peroxide compound,
For example, methyl ethyl ketone peroxide (half-life = 1
05 ° C, the same applies hereinafter), methyl isobutyl ketone peroxide (105 ° C), methylcyclohexane peroxide (96 ° C), cyclohexanone peroxide (9
Ketone peroxide compounds such as p-chlorobenzoyl peroxide (75 ° C), benzoyl peroxide (72 ° C), and acetyl peroxide (69).
° C), lauroyl peroxide (61 ° C), bis-
3,5,5-trimethylhexanoyl peroxide (60 ° C.), o-methylbenzoyl peroxide (5
7 ° C.), diacyl peroxide compounds such as 2,4-dichlorobenzoyl peroxide (54 ° C.) and isobutyryl peroxide (33 ° C.);

Di-t-butyl peroxide (126)
° C), t-butylcumyl peroxide (121 ° C),
1,3-bis (t-butylperoxyisopropyl) benzene (121 ° C.), 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (118 ° C.), dicumyl peroxide (117 ° C.) A) a dialkyl peroxide compound;

4,4-di-t-butylperoxy-n-
Butyl valerate (110 ° C), 2,2-di-t-butylperoxybutane (102 ° C), 1,1-di-t-butylperoxycyclohexane (97 ° C), 1,1-di-t- Peroxyketal compounds such as butylperoxy-3,3,5-trimethylcyclohexane (95 ° C.);

T-butyl peroxybenzoate (10
5 ° C.), t-butyl peroxyacetate (103
° C), t-butylperoxy-3,5,5-trimethylhexanoate (100 ° C), t-butylperoxyazelate (99 ° C), di-t-butylperoxyhexahydrophthalate (83 ° C) , T-butyl peroxyisobutyrate (78 ° C), t-butyl peroxy-2
-Ethylhexanoate (74 ° C), t-butylperoxypivalate (56 ° C), t-hexylperoxypivalate (53 ° C), t-hexylneohexanoate (49 ° C), t-butylperoxide Oxyneodecanoate (47 ° C), t-hexylperoxyneodecanoate (45 ° C), α-cumylperoxyneohexanoate (41 ° C), 2,4,4-trimethylpentyl-2-peroxy -2-neodecanoate (41 ° C), α-cumylperoxyneodecanoate (38 ° C), 2,4,4
Trimethylpentyl peroxyphenoxy acetate (38 ° C.), acetylcyclohexanesulfonyl (37
C));

T-butyl peroxyisopropyl carbonate (97 ° C.), di (3-methyl-3-methoxybutyl) peroxydicarbonate (47 ° C.), di (sec-
Butyl) peroxydicarbonate (45 ° C), diisopropyl peroxydicarbonate (45 ° C), bis (4-
t-butylcyclohexyl) peroxydicarbonate (44 ° C), di (2-ethylhexyl) peroxydicarbonate (44 ° C), di (methoxyisopropyl) peroxydicarbonate (44 ° C), di (3-methoxy Butyl) peroxydicarbonate (43 ° C), di (2-ethoxyethyl) peroxydicarbonate (43 ° C), dimyristyl peroxydicarbonate (41 ° C), di-n
-Peroxydicarbonate compounds such as propyl peroxydicarbonate (41 ° C), diallyl peroxydicarbonate (39 ° C);

As the azo compound, for example, 2-
Phenylazo-4-methoxy-2,4-dimethylvaleronitrile (122 ° C), 1,1'-azobis (cyclohexane-1-carbonitrile) (88 ° C), 2,2'-
Azobis (2-methylbutyronitrile) (67 ° C),
2,2'-azobis (2-methylpropionitrile)
(65 ° C), α, α'-azobis (2,4-dimethylvaleronitrile) (51 ° C), α, α'-azobis (2-
Cyclopropylpropionitrile) (42 ° C.), α,
α′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (30 ° C.) nadonoazonitrile compound;
Alkyl azo compounds such as 2,2′-azobis (2,4,4-trimethylpentane) (110 ° C.) are exemplified.

The amount of the chlorination reaction catalyst to be added is preferably in the range of 0.001 to 0.5% by weight, more preferably 0.005 to 0.1% by weight, based on PVC (weight).

Raw material CPVC100 to be charged at the time of the above polymerization
VCM is charged at a ratio of 20 to 50 parts by weight with respect to parts by weight. If the VCM is less than 20 parts by weight, even if the polymerization conversion rate of CPVC is increased, sufficient coating with PVC cannot be obtained, so that the gelling property is not improved and the moldability cannot be improved. When the VCM exceeds 50 parts by weight, the amount of the VCM is too large relative to the charged raw material CPVC, so that not only the raw material CPVC is coated, but also a large amount of new PVC particles are generated, and the heat resistance is improved. Be impaired.

The polymerization conversion of the charged VCM is limited to 5 to 15% by weight. If the polymerization conversion is less than 5% by weight, the coating on the raw material CPVC does not proceed sufficiently, and the improvement of the gelling property is not sufficient. If it exceeds 15% by weight, the coating on the raw material CPVC progresses too much, In order to reduce the porosity, the improvement of the gelling property is hindered, and the improvement of the heat resistance is impaired.

In the coating polymerization, the aqueous medium is preferably 100 to 250 parts by weight, more preferably 120 to 200 parts by weight, based on 100 parts by weight of the raw material CPVC.
If the amount is less than 100 parts by weight, the amount of the aqueous medium is too small, the particles become large during the coating polymerization, and the gelling property decreases. 25
If the amount is more than 0 parts by weight, the productivity of coating polymerization is undesirably reduced.

The fifth invention is directed to the raw material CPV according to the fourth invention.
This is a method for producing CPVC in which C is polymerized by using C having an average porosity of 28 to 39% by volume and an average particle diameter of 70 to 250 μm. Average porosity is 28-39
% By volume is preferred. Below 28% by volume, C
The gelling property of PVC is unfavorably reduced, and if it exceeds 39% by volume, the bulk specific gravity of CPVC tends to be reduced, and the productivity at the time of molding decreases.

The above raw material CPVC has an average particle size of 70 to 2
50 μm is preferred. If it is less than 70 μm, the raw material CPVC to be coated will aggregate with each other due to the VCM added at the time of coating polymerization. The PVC cannot be uniformly coated on the raw material CPVC, and the gelling property also decreases.

The sixth invention is directed to a PV coating the raw material CPVC.
1 shows a preferred polymerization recipe of C, and the polymerization recipe presents a method for producing a PVC having a thin skin layer and good gelling property. That is, as the at least one dispersant selected from the group consisting of partially saponified polyvinyl acetate (a) and the cellulose derivative (b) in the reaction system, those exemplified in the second invention are similarly used. .

The at least one emulsifier selected from the group consisting of the higher sorbitan fatty acid ester (c) having an HLB value of 3 to 10 and the anionic emulsifier (d) includes those exemplified in the second invention. , Are similarly used.
Further, a higher fatty acid (e) having 8 to 25 carbon atoms and a 0.1% by weight aqueous solution at normal temperature and pressure are 10 to 200 cP.
As the thickener (f) having the Brookfield's viscosity described above, those exemplified in the second invention are similarly used.

In the sixth invention, P is added in the presence of the raw material CPVC.
The average degree of polymerization in the case of suspension polymerization of VC is based on the raw material CPVC.
Is preferable. When the average degree of polymerization of PVC decreases more than 200 with respect to the raw material CPVC,
If the heat resistance is lowered and is higher than 200, the effect of improving the gelling property by coating is reduced, which is not preferable.

[0095]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Example 1) [Preparation of PVC] A partially saponified polyvinyl acetate (hereinafter, referred to as PVA) was added to a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and 40 kg of deionized water and parts by weight of VCM were used. Degree of saponification 72 mol% and degree of polymerization 700) 50
0 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
550 ppm of walnut peroxyneodecanoate were introduced. Next, after degassing the inside of the polymerization vessel to 45 mmHg, 40 kg of VCM was charged and stirring was started.

After heating the polymerization vessel to 57 ° C., the temperature was kept constant and the polymerization was continued. At the time when the polymerization conversion rate is 65% by weight, the temperature inside the polymerization vessel is started, and when the polymerization conversion rate is 80% by weight, the temperature is raised to 70 ° C.
The temperature was kept at 0 ° C. When the polymerization conversion reached 93% by weight, the reaction was terminated. After the unreacted VCM in the polymerization vessel was recovered, the polymer was taken out of the system in the form of a slurry, and dehydrated and dried to obtain PVC. The BET surface area of this resin is 3.2 m ²
/ G. When the skin-free ratio was measured by SEM photograph observation, almost no skin layer was observed, and 98%
Met. The average degree of polymerization was 1020. Note that B
The measurement of the ET specific surface area, the measurement of the skin-free ratio, and the measurement of the average degree of polymerization were performed by the following methods.

[Preparation of CPVC] 70 kg of deionized water (resin ratio to resin = 2) and 35 kg of the PVC obtained above were added to a glass-lined reactor having an internal volume of 250 liters.
And stirring to disperse the PVC in water,
Thereafter, the reactor was kept at 30 ° C. Next, nitrogen gas was blown into the reactor, and the inside of the reactor was replaced with nitrogen gas. Next, 70 kg of liquid chlorine [resin amount ratio = 2], which was previously kept at 30 ° C., was introduced into the reactor. At this point, the pressure in the reactor was 0.75 MPa. After the introduction of liquid chlorine, the mixture was stirred for about 1 hour while maintaining the temperature at 30 ° C. Thereafter, as a chlorination reaction catalyst, di-2-ethylhexyl peroxydicarbonate was added at 300 ppm (weight ratio) to PVC to start the chlorination reaction substantially. Thereafter, the concentration of hydrochloric acid in the vessel was measured, and the chlorination reaction was continued while examining the progress of the chlorination reaction. When the chlorine content of the generated CPVC reached 69.0% by weight, the chlorination reaction was continued. Was terminated. The reaction time was 110 minutes. Furthermore, nitrogen gas was blown into the vessel to remove unreacted chlorine. The obtained resin was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdery CPVC resin. The chlorine content of the obtained CPVC was 69.0% by weight.

(Example 2) [Preparation of PVC] The same procedure as in Example 1 was carried out except for the conditions shown in Table 1. [Preparation of CPVC resin] 140 kg of deionized water [resin amount ratio = 4] and 35 kg of PVC obtained above were put into a glass-lined reactor having an internal volume of 250 liters, and the PVC was stirred and dispersed in water. Raise the temperature of the reactor to 1
It was kept at 10 ° C. Next, nitrogen gas was blown into the reactor, and the inside of the reactor was replaced with nitrogen gas. Next, chlorine gas was blown into the reactor to chlorinate PVC. Thereafter, the concentration of hydrochloric acid in the vessel was measured and the chlorination reaction was continued while examining the progress of the chlorination reaction. When the chlorine content of the generated CPVC reached 69.0% by weight, the supply of chlorine gas was started Was stopped to terminate the chlorination reaction. The chlorination reaction catalyst and the pressure during the reaction were as shown in Table 1. Furthermore, nitrogen gas was blown into the vessel to remove unreacted chlorine, and the obtained resin was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdery CPVC. The chlorine content of the obtained CPVC was 69.0% by weight.

(Example 3) [Preparation of PVC] The same procedure as in Example 1 was carried out except for the conditions shown in Table 1. [Preparation of CPVC resin] 140 kg of deionized water [resin amount ratio = 4] and 35 kg of PVC obtained above were put into a glass-lined reactor having an internal volume of 250 liters, and the PVC was stirred and dispersed in water. The reactor was heated to 7
It was kept at 0 ° C. Next, nitrogen gas was blown into the reactor, and the inside of the reactor was replaced with nitrogen gas. Next, chlorine gas was blown into the reactor, and PVC was chlorinated while irradiating the inside with ultraviolet light using a mercury lamp. Thereafter, the concentration of hydrochloric acid in the vessel was measured, and the chlorination reaction was continued while examining the progress of the chlorination reaction.
When reaching 9.0% by weight, the supply of chlorine gas is stopped,
The chlorination reaction was terminated. Furthermore, nitrogen gas was blown into the vessel to remove unreacted chlorine, and the obtained resin was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdery CPVC. The chlorine content of the obtained CPVC is:
It was 69.0% by weight.

(Example 4) [Preparation of PVC] The same procedure as in Example 1 was carried out except for the conditions shown in Table 1. The polymerized resin was a resin having a skin layer, similarly to the resin obtained by the suspension polymerization. [Preparation of CPVC] Example 1 was used except for the conditions shown in Table 3.
Was performed in the same manner as described above.

(Example 5) [Preparation of PVC] The same procedures as in Example 4 were carried out except for the conditions shown in Table 1. [Preparation of CPVC] Example 3 was repeated except for the conditions shown in Table 3.
Was performed in the same manner as described above.

(Comparative Examples 1 and 3) [Preparation of PVC] The same procedures as in Example 4 were carried out except for the conditions shown in Table 2. [Preparation of CPVC] Except for the conditions shown in Table 4, Example 2 was used.
Was performed in the same manner as described above.

(Comparative Example 2) [Preparation of PVC] The same procedure as in Example 4 was carried out except for the conditions shown in Table 2. [Preparation of CPVC] Example 3 was used except for the conditions shown in Table 4.
Was performed in the same manner as described above.

(Comparative Example 4) [Preparation of PVC] The same procedure as in Example 1 was carried out except for the conditions shown in Table 2. [Preparation of CPVC] Except for the conditions shown in Table 4, Example 2 was used.
Was performed in the same manner as described above.

(Comparative Example 5) [Preparation of PVC] The same procedures as in Example 1 were carried out except for the conditions shown in Table 2. [Preparation of CPVC] Example 3 was used except for the conditions shown in Table 4.
Was performed in the same manner as described above.

[0107]

[Table 1]

[0108]

[Table 2]

[0109]

[Table 3]

[0110]

[Table 4]

(Example 6) [Preparation of PVC] In a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, PVA (average saponification degree 72 mol% and polymerization degree 700 ) 400 ppm, sorbitan monolaurate 16
100 ppm, lauric acid 1400 ppm, polyacrylamide (with a Brookfield viscosity of 51 cps of a 0.1% by weight aqueous solution at 20 ° C. and 1 atm) 100 pp
m and α-walnut peroxy neodecanoate 5
50 ppm was charged. Next, 45 mmH
After degassing to 40 g, 40 kg of VCM was charged and stirring was started.

After heating the polymerization vessel to 57 ° C., the temperature was kept constant until the polymerization was completed. When the polymerization conversion rate is 90% by weight, the reaction is terminated, and the unreacted VCM in the polymerization vessel is recovered. Then, the polymer is taken out of the system in the form of a slurry, dehydrated and dried, and dried.
C was obtained. When the skin free ratio was measured by SEM photograph observation, no skin layer was observed, and it was 100%. The average degree of polymerization was 1,000. The average porosity was 35% by volume, and the average particle size was 200 μm. The measurement of the average porosity and the measurement of the average particle diameter were performed by the following methods.

[Preparation of Raw Material CPVC] 105 kg of deionized water (resin ratio to resin = 3) and 35 kg of the PVC obtained above were placed in a 250 liter internal pressure resistant titanium reactor.
Stir to disperse the PVC in the water, then bring the reactor to 80
C. Next, nitrogen gas is blown into the reactor,
The inside of the vessel was replaced with nitrogen gas. Next, after introducing gaseous chlorine into the reactor, hydrogen peroxide is used as a chlorination reaction catalyst in a PV system.
400 ppm (weight ratio) with respect to C was appropriately diluted and supplied in a state of hydrogen peroxide solution. Thereafter, PVC was chlorinated while irradiating the inside of the vessel with ultraviolet rays using a mercury lamp. Thereafter, the concentration of hydrochloric acid in the vessel was measured, and the chlorination reaction was continued while examining the progress of the chlorination reaction. Was terminated. The reaction time was 250 minutes. Furthermore,
Unreacted chlorine was removed by blowing nitrogen gas into the vessel, and the obtained resin was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdery CPVC resin. The chlorine content of the obtained CPVC was 72.0% by weight.

[Preparation of coated CPVC] Deionized water 3 was placed in a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters.
7.5 kg and 25 kg of the above-obtained CPVC are charged, and further, 400 parts by weight of PVA (average degree of saponification: 72 mol% and degree of polymerization: 700) with respect to parts by weight of VCM described later.
m, sorbitan monolaurate 1600 ppm, lauric acid 1400 ppm, polyacrylamide (20 ° C., 1
100 ppm of a 0.1% by weight aqueous solution at atmospheric pressure and a Brookfield viscosity of 51 cps) and 300 ppm of α-walmi peroxyneodecanoate were added. Next, after degassing the inside of the polymerization vessel to 45 mmHg,
10 kg of VCM (= 40 parts by weight relative to CPVC) was charged and stirring was started.

After heating the polymerization vessel to 57 ° C., the temperature was kept constant until the polymerization was completed. When the polymerization conversion rate is 11% by weight, the reaction is terminated, and after the unreacted VCM in the polymerization vessel is recovered, the polymer is taken out of the system in the form of slurry, dehydrated and dried, and
C-coated CPVC was obtained. When the skin-free ratio was measured by SEM photograph observation, no skin layer was observed and 100%
Met. The average degree of polymerization of the coated PVC was 1,000. The measurement of the weight change before and after the coating polymerization showed that the coating ratio was 4.4 parts by weight, assuming that the original CPVC was 100 parts by weight.

(Examples 7 to 9) [Preparation of PVC] The same procedures as in Example 6 were carried out except for the conditions shown in Table 5. [Preparation of raw material CPVC] The same procedures as in Example 6 were carried out except for the conditions shown in Table 5. [Preparation of coated CPVC] The same procedure as in Example 6 was carried out except for the conditions shown in Table 7.

(Comparative Examples 6 and 7) [Preparation of PVC] The same procedures as in Example 6 were carried out except for the conditions shown in Table 6. [Preparation of raw material CPVC] The same procedures as in Example 6 were carried out except for the conditions shown in Table 6. [Preparation of coated CPVC] The same procedure as in Example 6 was carried out except for the conditions shown in Table 8.

(Comparative Examples 8 and 9) [Preparation of PVC] The same procedures as in Example 6 were carried out except for the conditions shown in Table 6. [Preparation of raw material CPVC] The same procedures as in Example 6 were carried out except for the conditions shown in Table 6. [Preparation of coated CPVC] No coating polymerization is performed.

The PVC and CPVC 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 to 8.

[0120]

[Table 5]

[0121]

[Table 6]

[0122]

[Table 7]

[0123]

[Table 8]

(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) Initial coloration To 100 parts by weight of PVC, 2 parts by weight of dimethyltin mercapto (organotin-based stabilizer; product number "JF-10B"; manufactured by Sankyoki Co., Ltd.) and montanic acid ester (lubricant; product number "WAX- O
P "; Hoechst) 0.5 parts by weight, and heated to 120 ° C. using a super mixer (Mitsui Miike).
After mixing, the sheets obtained by kneading with two rolls at 165 ° C. for 5 minutes are overlapped and pressed at 165 ° C. for 5 minutes to obtain a sheet.
mm sheet is obtained. The sheet was placed on a white mount, and the degree of coloring was visually determined. A sample without coloring was judged as "good", and a sample with slight coloring was judged as "poor".

(3) Particle size distribution According to JIS Z 8801, 60 mesh and 2
Using a 00 mesh sieve, sieving was performed to calculate the amount of resin passing (% by weight), and a 60 mesh on product (% by weight) and a 200 mesh pass product (% by weight) based on the total weight.
The total (% by weight) of less than 1% by weight is “good”, 1% by weight
Less than 3% by weight was judged as "OK", and more than 3% by weight was judged as "poor".

(4) Evaluation of surface condition (skin-free ratio) The PVC particles obtained in Examples and Comparative Examples were scanned with a scanning electron microscope (FE-SEM S-4200, manufactured by Hitachi, Ltd.).
The image was taken at an accelerating voltage of 2 kV and a magnification of 130 times, and the outline 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 skin-free portion) were traced paper. (Or OHP sheet)
Copy to Next, the tracing paper (or OHP sheet) is converted to an image analysis device (Pias-II, PIAS-II).
Introduced in I), 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

(5) 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.

(6) Processability (Measurement of Gelation Temperature) Using “Rheocord 90” manufactured by Haake, 55 g of the following resin composition was heated at 150 rpm at a rotation speed of 40 rpm.
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.

(7) 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.

(8) Vicat Softening Temperature A 5 mm thick CPVC sheet prepared in the above thermal stability test was cut into 15 mm squares to prepare a sample for measurement.
It measured based on SK7206 (weight 1.0kgf).

[0132]

According to the method for producing CPVC of the present invention, the degree of polymerization on the outside of the resin particles can be adjusted to be relatively low and the distribution of chlorination can be controlled by the methods of the first to third aspects. According to the method of the fourth to sixth inventions, the raw material CPVC
Is coated with PVC, it is possible to provide CPVC having excellent gelling performance and heat resistance.

Claims (6)

[Claims] 1. A method for producing a chlorinated vinyl chloride resin obtained by chlorinating a vinyl chloride resin, wherein a vinyl chloride monomer is dissolved in an aqueous medium in the presence of a dispersant and an oil-soluble polymerization initiator. The suspension polymerization is started at a predetermined polymerization temperature, and after the polymerization conversion reaches 60% by weight, the temperature is raised, and the polymerization is continued at a temperature higher than the polymerization temperature by 5 to 25 ° C. A method for producing a chlorinated vinyl chloride resin, comprising producing a resin and chlorinating the obtained vinyl chloride resin. 2. A dispersant selected from the group consisting of partially saponified polyvinyl acetate (a) and cellulose derivative (b) in a vinyl chloride monomer in the presence of an oil-soluble polymerization initiator. , At least one emulsifier selected from the group consisting of sorbitan higher fatty acid ester (c) having an HLB value of 3 to 10 and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and A 0.1% by weight aqueous solution at normal temperature and normal pressure is added with a thickener (f) having a Brookfield's viscosity of 10 to 200 cP, and suspension polymerization is started at a predetermined polymerization temperature in an aqueous medium. After the temperature reached 60% by weight, the temperature was raised to complete the temperature rise before the polymerization conversion rate reached 85% by weight.
2. The method for producing a chlorinated vinyl chloride resin according to claim 1, wherein the polymerization is continued at a temperature higher by 25 DEG C. to produce the vinyl chloride resin. 3. After a vinyl chloride resin is suspended in an aqueous medium, liquid chlorine or gaseous chlorine is introduced into the reactor, and a 10-hour half-life is selected from the group consisting of 20 to 60 ° C. The method for producing a chlorinated vinyl chloride resin according to claim 1 or 2, wherein the chlorination reaction is carried out at a reaction temperature of 20 to 60 ° C in the presence of at least one oil-soluble initiator. 4. A chlorinated vinyl chloride resin having a chlorine content of 66 to 75% by weight when producing a chlorinated vinyl chloride resin obtained by polymerizing a vinyl chloride monomer on the surface of a chlorinated vinyl chloride raw material resin. The raw material resin is made into a suspended state in the presence of a vinyl chloride-based monomer, a dispersant and an oil-soluble initiator. 20 to 50 parts by weight of a monomer are charged,
A method for producing a chlorinated vinyl chloride resin, wherein the suspension polymerization is carried out until the polymerization conversion of the vinyl chloride monomer becomes 5 to 15% by weight. 5. An average porosity of 28 to 39% by volume,
The method for producing a chlorinated vinyl chloride-based resin according to claim 4, wherein a chlorinated vinyl chloride-based raw material resin having an average particle diameter of 70 to 250 µm is used. 6. A vinyl chloride monomer selected from the group consisting of partially saponified polyvinyl acetate (a) and a cellulose derivative (b) in the presence of a chlorinated vinyl chloride raw material resin and an oil-soluble initiator. At least one dispersant, at least one emulsifier selected from the group consisting of sorbitan higher fatty acid esters (c) having an HLB value of 3 to 10 and anionic emulsifier (d); Fatty acid (e) and a thickener (f) having a Brookfield's viscosity of 10 to 200 cP in a 0.1% by weight aqueous solution at normal temperature and normal pressure are added, and suspension polymerization is performed at a predetermined polymerization temperature in an aqueous medium. Starting, the average degree of polymerization of the vinyl chloride resin covering the chlorinated vinyl chloride-based resin is suspension polymerization until the average degree of polymerization of the chlorinated vinyl chloride-based resin becomes ± 200. Motomeko 4 or 5 method for producing a chlorinated vinyl chloride resin according.