JPH0132844B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a chlorinated vinyl chloride resin having excellent heat resistance and thermal stability. More specifically, a vinyl chloride resin obtained by completing aqueous suspension polymerization at a polymerization conversion rate of 40 to 70% is used as a raw resin, the raw resin is suspended in an aqueous medium, and the resin is suspended in an aqueous medium. The oxygen mixing rate is 1000ppm
The present invention relates to a method for producing a chlorinated vinyl chloride resin, which is characterized by introducing the following chlorine gas (based on the total amount of introduced gas) and performing post-chlorination. Vinyl chloride resin has excellent weather resistance, chemical resistance, and processability, and is also flame retardant, so it is used in extremely large quantities in a wide range of fields. The biggest drawback of this material is its low softening temperature, which imposes considerable restrictions on applications that require heat resistance. In order to overcome this limitation and improve the softening temperature of vinyl chloride resins, it is known to produce chlorinated vinyl chloride resins by post-chlorinating vinyl chloride resins. The methods include solution chlorination, which involves blowing chlorine gas into an organic solvent solution of vinyl chloride resin, suspension chlorination, which blows chlorine gas into an organic solvent suspension or aqueous suspension of vinyl chloride resin, and chlorination. A direct chlorination method is known in which vinyl resin powder is brought into direct contact with chlorine gas, but a solution chlorination method using an organic solvent such as tetrachlorethane or dichloroethane,
Alternatively, in the organic solvent suspension method, it is difficult to separate the chlorinated vinyl chloride resin, and it is necessary to recover a large amount of solvent. In the direct chlorination method, which is usually carried out in the presence of an azo compound, an inorganic compound such as titanium tetrachloride, phosphorus pentachloride, or antimony trichloride, or a catalyst such as τ rays or ultraviolet rays, the vinyl chloride resin is not uniformly chlorinated. The problem is that it is easily subject to change. The present invention relates to a method for producing a chlorinated vinyl chloride resin using a post-aqueous suspension chlorination method in which chlorine gas is blown into the above-mentioned aqueous suspension. Therefore, in the above-mentioned aqueous suspension chlorination method, an aqueous medium containing a swelling agent, i.e., a hydrochloromethylene compound, etc., in an amount of 5 to 25% by volume based on the total liquid volume is used as an aqueous suspension. The proposal of Japanese Patent Publication No. 36-888 was to carry out chlorination at a temperature of 65°C or lower, while always maintaining an excess dissolved chlorine concentration, and under a low photochemical activation effect that could maintain a relative excess chlorine concentration. When a vinyl chloride resin is made into an aqueous suspension that does not substantially contain a solvent or a swelling agent for the vinyl chloride resin and chlorinated under ultraviolet irradiation, instead of adjusting the chlorine concentration, a specific chlorine within a certain reaction rate until the displacement amount is reached.
Special Publication 1977 that adjusts the unit amount of ultraviolet irradiation over time
-48795, etc., but even after post-chlorination according to these methods, although the chlorine content of the obtained chlorinated vinyl chloride resin is the same, the chlorinated vinyl chloride resin is often It was found that the heat resistance of the resins differed greatly, and that there were problems that needed to be further improved in order to obtain chlorinated vinyl chloride resins after the quality of heat resistance was constant. The present inventor focused on the above-mentioned industrially advantageous aqueous suspension type post-chlorination method, and found that it has a high degree of heat resistance, and that after the quality of the heat resistance is constant, chlorinated vinyl chloride resin is used. In order to provide a method for producing a chlorinated vinyl resin, we will discuss known chlorination factors, the amount and type of swelling agent in the aqueous medium, the purity and introduction rate of the chlorine gas introduced, the effects of light and chlorination aids, etc. Despite extensive research into numerous factors such as accelerators, ultraviolet wavelengths, reaction temperatures, etc., changes in these known factors did not yield satisfactory results, and surprisingly, changes in polymerization conversion rates were not achieved. A vinyl chloride resin produced by aqueous suspension polymerization in a specific range is used as a raw material resin, and when the vinyl chloride resin is suspended in an aqueous medium and then chlorinated, It was discovered that the above-mentioned heat resistance quality problem could be solved only by using a chlorine gas with an oxygen content less than that, and that the chlorinated vinyl chloride resin also exhibited excellent thermal stability. This led to the completion of the present invention. That is, the present invention provides a method for producing a chlorinated vinyl chloride resin of constant quality and having high heat resistance and thermal stability using an aqueous suspension chlorination method. "Aqueous suspension polymerization" as used in the present invention refers to dispersing monomers in an aqueous medium to form a suspension, and using a polymerization catalyst that is soluble in the monomers, the suspended monomers are The polymerization reaction is carried out in a small container, and is also called granular polymerization or pearl polymerization. In the above aqueous suspension polymerization, it is difficult to disperse the monomers well with stirring alone, so polymer dispersants, inorganic compounds, surfactants, etc. are usually used as suspension stabilizers. Polymer dispersants used as suspension stabilizers include natural polymers such as gelatin, starch, sorbitol, and pectin, and synthetic polymers such as partially saponified polyvinyl alcohol, methyl cellulose, and ethyl. Cellulose, hydroxymethylcellulose, hydroxyprocellulose, CMC, methyl starch,
Polyethylene glycol starch, polyvinyl methyl ether, polyvinyl pyrrolidone, maleic acid or its derivatives, maleic acid, maleic anhydride, maleic anhydride and vinyl acetate copolymer, copolymer of maleic anhydride with vinyl methyl ether, maleic anhydride copolymer of acid and ethylene,
Copolymers of maleic acid or maleic anhydride and alkyl acrylates, partial esters of copolymers of ethylene and maleic anhydride, copolymers of styrene, vinyl acetate, and maleic anhydride or maleic acid, and salts thereof. , saponified products thereof, and other saponified products of copolymers of vinyl acetate and acrylic ester, sodium alginate, polymethacrylic acid, etc.; non-acid compounds include metal salts of sodium, calcium, baium, aluminum, etc.
Barium, calcium, sulfates and hydrochlorides of barium, carbonates of calcium and magnesium, hydroxides of zinc and calcium, others, calcium phosphate, sodium oxalate, calcium oxalate, calcium tartrate, bentonite, silica gel, etc.; interfaces; Active agents include various surfactants such as anionic, cationic, and nonionic surfactants, sorbitan fatty acid esters,
polyoxyethylene sorbitan fatty acid ester,
Polyoxyethylene sorbitol fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene higher alcohol ether, glycerin fatty acid ester, propylene glycol fatty acid ester, polyoxyethylene lanolin derivative, polyoxyethylene sorbitol monoderivative, polyoxyethylene human oil Derivatives, polyoxypropylene polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol formaldehyde condensates, acetylated monoglycerides, polyoxyethylene alkyl amines and amides, polyoxyethylene lanolin alcohol derivatives, polyoxyethylene alkyl phenyl ethers, alkyl Sulfuric ester salts, dialkyl sulfosuccinates, polyether alcohol sulfuric esters, alkyl phosphoric esters, acyl sarcosinates, lower and higher alcohol fatty acid esters, fatty acids and higher alcohols, other initial condensates of synthetic resins, etc. These materials can be used alone or in combination of two or more, if necessary. As a medium, not only water but also 3 to 20% by weight of an organic solvent such as methanol, ethanol, propanol, etc. can be added as necessary.Also, as a polymerization medium, various peroxides, azo compounds, such as benzoyl peroxide, lauroyl peroxide, acetyl peroxide, octanoyl peroxide, decanoyl peroxide, m-toluoyl peroxide, isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, cyclohexanone peroxide, succinic acid peroxide, Acetyl cyclohexyl sulfonyl peroxide, 3,5,5
-trimethylhexanoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, t-butylcumyl peroxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide,
t-Butyl hydroperoxide, kyumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-
Dimethylhexane-2,5-dihydroperoxide, di-isopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxydicarbonate, di(2-ethylhexyl)peroxide Oxydicarbonate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, t-butylperoxyisopropyl carbonate, t-butylperoxypivalate, t-butylperoxylaurate, t-butylperoxyiso ptylate, t-butylperoxyacetate, t-butylperoxybenzoate, di-t-butyldiperoxyisophthalate, n-butyl-4,4-
Bis(t-butylperoxy)valerate, t-
Butyl peroxy (2-ethylhexanoate),
1,1-bis(t-butylperoxy)cyclohexane, t-butylperoxymaleic acid, t-butylperoxy 3,5,5-trimethylhexanoate, 2,2-bis(t-butylperoxy)
Butane, a, d-bis(t-butylperoxyisopropyl)benzene, etc.; azobisisobutyronitrile, azobisdimethylvaleronitrile, azodiisobutyrate, etc.; One or more types can be used as appropriate. Furthermore, in addition to the vinyl chloride homopolymer polymerized by the aqueous suspension polymerization method described above, the vinyl chloride resin used in the present invention refers to one or two resins containing vinyl chloride as a main component and copolymerizable with vinyl chloride. It includes copolymers or graft polymers produced by copolymerizing a mixture with more than one type of monomer. Monomers that can be copolymerized with the above vinyl chloride include vinylidene chloride, vinyl acetate, vinyl bromide,
Higher alkyl vinyl ethers (e.g. dodecyl vinyl ether, etc.), acrylonitrile, acrylic esters (e.g. methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, etc.), methacrylic esters (e.g. methyl methacrylate, methacrylic acid) (ethyl, propyl methacrylate, butyl methacrylate, etc.), acrylamide, methacrylamide, ethylene, propylene, styrene, and the like. The above-mentioned suspension polymerization is generally carried out using a formulation containing 50 to 300 parts by weight of deionized water, 0.05 to 1 part by weight of a suspension stabilizer, and 0.01 to 1 part by weight of a polymerization catalyst to 100 parts by weight of monomer. The reaction is carried out at a polymerization temperature of 35 to 80°C, a reaction time of 3 to 16 hours, and stirring conditions appropriately determined depending on the shape of the polymerization reaction tank. As mentioned above, the vinyl chloride resin obtained by aqueous suspension polymerization used in the present invention is one whose polymerization is completed at a polymerization conversion rate of 40 to 70% in the aqueous suspension polymerization. There is a need. In the present invention, the polymerization conversion rate (%) refers to the value obtained by dividing the weight of the polymer produced in aqueous suspension polymerization by the total weight of the monomers charged in the polymerization, multiplied by 100. Even if a vinyl chloride resin with a polymerization conversion rate of 70% or more is used as a raw material and is suspended in an aqueous medium and then chlorinated, the resulting chlorinated vinyl chloride resin has low heat resistance, which is undesirable. When using a polyvinyl chloride resin with a polymerization conversion rate of less than 40%, operations such as washing, dehydration, etc. separation and drying of the vinyl chloride resin itself with the polymerization conversion rate are extremely difficult, and it is industrially disadvantageous. Even if the vinyl chloride resin is post-chlorinated, only a chlorinated vinyl chloride resin with poor thermal stability and easily changeable can be obtained, which is undesirable.
%, preferably in the range of 50-65%. As long as the vinyl chloride resin used in the present invention has a polymerization conversion rate in the range of 40 to 70%, any suitable vinyl chloride resin can be used without any limitations regarding the average polymerization number, particle size, and other properties. However, a resin having an average degree of polymerization of 400 to 2000 is preferable because it exhibits excellent impact resistance when the chlorinated vinyl chloride resin is processed into a molded product or the like. The aqueous medium used in the post-chlorination reaction in the present invention may consist only of water such as ion-exchanged water or industrial water, or may contain hydrochloric acid or the like to increase the solubility of chlorine. Appropriate amounts of carbon tetrachloride, organic solvents such as chromium form, surfactants,
There is no problem in adding a defoaming agent, etc., and preferably the amount of the aqueous medium is the same as the vinyl chloride resin mentioned above.
It can be used in a range of 100 to 700 parts by weight per 100 parts by weight. In addition, the method of suspending the vinyl chloride resin in the aqueous medium is a mechanical stirring method using a stirrer, etc., and the post-chlorination reaction temperature is a temperature below the softening temperature of the raw material vinyl chloride resin, Preferably
Temperatures of the aqueous medium from 20 to 80°C can be used. The post-chlorination reaction is carried out by suspending the vinyl chloride resin described above in the aqueous medium and introducing chlorine gas into it. It may be used alone, or it may be diluted with a gas such as nitrogen, hydrogen chloride, carbon dioxide, argon, or a halide of a lower hydrocarbon in an amount that does not substantially interfere with the reaction. however,
If more than 1000 ppm of oxygen is mixed in chlorine gas or diluted chlorine gas, it tends to deteriorate the thermal stability of the resulting post-chlorinated vinyl chloride resin, so the oxygen mixing ratio should be adjusted based on the total amount of introduced gas. but
It is preferably 1000 ppm or less, preferably 500 ppm or less.
The chlorination reaction is usually carried out under normal pressure, but may be carried out under increased pressure or reduced pressure, and further may be carried out at constant speed or variable speed. Thus, by the production method of the present invention, a chlorinated vinyl chloride resin having a high degree of heat resistance and a constant quality of heat resistance can be obtained; As content (%),
Post-chlorinated vinyl chloride resin is heated and decomposed in potassium hydroxide, and the generated chloride ions are titrated with silver nitrate using potassium chromate as an indicator.
A chlorine content of 62 to 70% according to the method of JISK-5634 is preferable. As the chlorine content of the post-chlorinated vinyl chloride resin increases, the softening temperature increases and the heat resistance improves, but at the same time, during processing of the post-chlorinated vinyl chloride resin, the melt viscosity also increases. Since the heat generation of the resin increases and approaches the decomposition temperature of the resin, if the chlorine content exceeds 70%, the thermal stability decreases and molding becomes extremely difficult, which is not preferred in practice. Moreover, those with a chlorine content of less than 62% are not preferred because of insufficient heat resistance. As described above, in the post-chlorination step of the present invention, an aqueous suspension-polymerized vinyl chloride resin obtained by completing polymerization with a polymerization conversion rate in the range of 40 to 70% is used as a raw material. The resin can be chlorinated without any particular restrictions, as long as it is chlorinated by introducing a chlorine-based gas with an oxygen content below a specified oxygen content in an aqueous medium. If a combination use is desired, it is preferable to carry out the post-chlorination step under a light emitting agent using the promoter as light. The light source is preferably a light source that emits visible light or ultraviolet light, such as a fluorescent lamp, a fluorescent chemical lamp, an incandescent electric lamp, a sodium vapor lamp, a neon discharge tube, a carbon arc lamp, or a high-pressure mercury lamp.
A light source that emits a large amount of light with a wavelength of 3000 to 6000 Å can be mentioned, and methods for adjusting the amount of light include:
Adjust the amount of light irradiated by adjusting the current of the light source continuously or intermittently by increasing or decreasing the number of light sources lit, changing the distance between the object to be irradiated (chlorinated vinyl chloride resin) and the light source, or adjusting the amount of light irradiated by adjusting the current of the light source, or by adjusting the amount of light emitted by aqueous media. Various methods can be used, such as a method in which a light absorber or the like is present to adjust the amount of light. The embodiments of the present invention will be described as follows. 1 Aqueous suspension polymerized vinyl chloride resin obtained by completing polymerization at a polymerization conversion rate of 40 to 70%,
Suspended in an aqueous medium, with an oxygen mixture ratio in it.
A method for producing chlorinated vinyl chloride resin by introducing chlorine gas of 1000 ppm or less (based on the total amount of introduced gas) and then chlorinating it. 2. The method for producing a chlorinated vinyl chloride resin according to item 1 above, wherein the post-chlorination is carried out under light irradiation. 3. The method for producing a chlorinated vinyl chloride resin according to any one of the above items 1 to 3, wherein the post-chlorination is carried out at a temperature of the aqueous medium of 20 to 80°C. 4. The method for producing a chlorinated vinyl chloride resin according to any one of the above items 1 to 4, wherein the post-chlorination is carried out at a chlorination content in the range of 62 to 70%. The chlorinated vinyl chloride resin of the present invention is obtained by using a special aqueous suspension-polymerized vinyl chloride resin and post-chlorinating it while suspended in an aqueous medium, and thus has a high degree of heat resistance and high quality. Because of its constant properties and excellent thermal stability, this resin is used alone or in combination with vinyl chloride resin, vinyl acetate resin, etc. in the field of pipes, sheets, films, and various other molded products. EVA resin, ABS resin, MBS resin,
It can be blended with one or more resins such as chlorinated polyethylene and used in a wide range of applications depending on the purpose. Hereinafter, the method for producing the post-chlorinated vinyl chloride resin of the present invention will be explained in detail with reference to Examples and Comparative Examples. [Manufacture of raw material vinyl chloride resin] Reference Examples 1 to 6 In a stainless steel polymerization tank with a capacity of 300 and equipped with a stirrer, 140 mL of ion-exchanged water and partially saponified polyvinyl acetate (Kurashiki Rayon Co., Ltd.) as a suspension stabilizer were added. (trade name: L-8) and 70 g of a toluene solution containing tertiary butylperoxypivalate at a concentration of 70% by weight as a polymerization initiator, and after reducing the pressure in the polymerization tank and replacing the air with nitrogen, vinyl chloride-based tree body
Prepare 110Kg. Then, the temperature was increased to 58℃ for 30 minutes while stirring at 300rpm.
Then, while maintaining this temperature (internal pressure approximately 9 kg/cm ² ), polymerization was carried out for the reaction time shown in Table 1, unreacted vinyl chloride monomer was recovered, and the centrifuge was removed. After washing with water, dehydrating and drying, vinyl chloride resins having different polymerization conversion rates (%) were obtained.

[Manufacture of chlorinated vinyl chloride resin]

Example 1 500g of vinyl chloride resin (A) obtained in Reference Example 1
and 2.5 liters of water into a glass-lined tank with a capacity of 5. While thoroughly stirring the contents at 300 rpm, nitrogen gas is blown in to replace the air in the reaction system.
Next, it was heated and kept at 60℃, and chlorine gas was introduced into the system at a flow rate of 50g/min to keep the oxygen content below 500ppm, and the temperature was about 6.5℃ under irradiation with a 100W high-pressure mercury lamp.
Post-chlorination reaction is carried out for approximately 7 hours until the chlorine content reaches approximately 66%. After the reaction, the generated chlorinated vinyl chloride resin is passed through a centrifuge, and the attached chlorine and hydrochloric acid are washed with water. Removed and dried. The end point of the post-chlorination reaction was determined from quantitative analysis of hydrochloric acid produced in the side reaction. Table 2 shows the raw material vinyl chloride resin used, the oxygen content in the chlorine gas, the reaction time, and the results of chlorine content analysis (JIS, K5634) of the produced chlorinated vinyl chloride resin. Examples 2 and 3 and Comparative Examples 1 and 2 In Example 1, instead of using the vinyl chloride resin (A) obtained in Reference Example 1, the vinyl chloride resin (B) obtained in Reference Examples 2 to 5 was used. A post-chlorination reaction was carried out in the same manner except for using each of ) to (E) to obtain a chlorinated vinyl chloride resin. Table 2 shows the raw material vinyl chloride resin used, the oxygen content in the chlorine gas, the reaction time, and the chlorine content analysis results of the produced chlorinated vinyl chloride resin. Comparative Example 3 A chlorinated vinyl chloride resin was obtained in the same manner as in Example 1, except that chlorine gas with an oxygen content of 2000 ppm was used. Raw material vinyl chloride resin used,
Table 2 shows the oxygen mixture ratio in the oxygen gas in the chlorine gas, the reaction time, and the analysis results of the chlorine content of the produced chlorinated vinyl chloride resin.

[Table] Table 3 shows the results of measuring the heat resistance and thermal stability of the chlorinated vinyl chloride resin thus obtained. The heating deformation temperature (° C.) indicating heat resistance, the gear oven (minutes) indicating thermal stability, and the degree of plate coloring shown in Table 3 were measured by the following method. (1) Heating deformation temperature (i) Preparation of test piece. Butyltin malate (manufactured by Nitto Kasei Co., Ltd.; N-
A compound containing 3 parts by weight of Montanic acid wax (manufactured by Hoechst; 2 parts by weight of Hoechst Wax (OP)) and 5 parts by weight of MBS resin (manufactured by Mitsubishi Rayon Co., Ltd.; Metablen C-102) was applied to the roll surface. The mixture was put into a mixing roll with a gap of 0.55 mm set at a temperature of 180°C, mixed for 10 minutes, and then taken off the roll.
Cool and create a roll sheet. Next, the rolled sheets were cut, 12 sheets were stacked, and heated at 190°C.
Press at 30Kg/ ^cm2 for 10 minutes to make a press plate with a thickness of about 13mm, length 12.7mm, width 12.7mm, length 120mm.
Prepare a test piece with dimensions. (ii) Measurement of heating distortion temperature The heating distortion temperature (°C) of the test piece prepared by the method described in item (i) above is measured using the JKS K-2707 test method. The temperature is increased at a constant rate of 2°C per minute under a specified load, and the temperature is measured when a deflection of 0.26 mm occurs. (2) Thermal stability (i) Gear open test The roll sheet piece obtained by the method described in (i) of (1) above was left in a gear open at 180°C and the time (minutes) for it to turn black was measured. vinegar. (ii) Coloring degree test The rolled sheet piece obtained by the method described in (i) of (1) above was pressed at 180°C for 5 minutes to make a 2 mm thick pressed plate, and the degree of coloring of the obtained pressed plate was determined. The results are compared and graded into five grades. Coloration degree 1...Colorless and transparent; Coloration degree 5...Yellowish brown transparent

[Table] As is clear from the test results in Table 3, the vinyl chloride resins of Examples 1 to 3 with polymerization conversion rates of 42.9% to 67.9% were used as raw materials, and chlorine gas with an oxygen content of 500 ppm or less was used. The chlorinated vinyl chloride resin showed excellent performance in terms of heat resistance and thermal stability. Vinyl chloride resin had excellent heat resistance, but it was not easy to wash and dehydrate after post-chlorination, and it had poor thermal stability, etc. On the other hand, the polymerization conversion rate of Comparative Example 2 was 70%. Chlorinated vinyl chloride resins made from vinyl chloride resins exceeding 75% have poor heat resistance and are not suitable for use in highly heat resistant applications. In addition, chlorinated vinyl chloride resins using chlorine gas with an oxygen content exceeding 1000 ppm had excellent heat resistance but poor thermal stability.

Claims (1)

[Claims] 1 The aqueous suspension-polymerized vinyl chloride resin obtained by completing the polymerization at a polymerization conversion rate of 40 to 70% is suspended in an aqueous medium, and the oxygen mixing ratio is
A method for producing chlorinated vinyl chloride resin, which is characterized by introducing chlorine gas of 1000 ppm or less (based on the total amount of introduced gas) and then chlorinating it.