JP2002060420A - Method for producing chlorinated vinyl chloride resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a method for producing a chlorinated vinyl chloride resin by chlorinating a vinyl chloride resin in an aqueous suspension, wherein the initial coloration of the resin during processing is reduced, and the productivity of the resin is improved without sacrificing its heat stability by shortening the chlorination time. SOLUTION: The average reaction rate during the reaction is within the range of 2-4 mol/hr per kg of the vinyl chloride resin, and the maximum reaction temperature is kept at 85 deg.C or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a chlorinated vinyl chloride resin. More specifically, by controlling the average reaction rate to a specific range and suppressing the maximum reaction temperature to 85 ° C. or lower, the initial coloring can be suppressed, and the productivity can be significantly improved without lowering the thermal stability. It is intended to provide a method for producing a chlorinated vinyl chloride resin.

[0002]

2. Description of the Related Art Chlorinated vinyl chloride resins have the property of improving the heat resistance of vinyl chloride resins by chlorination, and are used in a wide range of fields such as heat-resistant pipes, heat-resistant industrial boards, heat-resistant films and sheets. It is used.

[0003] The resin is produced by suspending a vinyl chloride resin in an aqueous medium and chlorinating the suspension while supplying chlorine. At the time of chlorination, in order to generate chlorine radicals, ultraviolet irradiation by a mercury lamp (photo chlorination method), excitation by heat (thermal chlorination method), excitation by catalyst (catalytic chlorination method)
Alternatively, a combination of these methods is generally performed.

Conventionally, various attempts have been made to improve the productivity of the resin and reduce the production cost. Typical productivity improvement methods include a method of improving the productivity by shortening the reaction time of the chlorination reaction, a method of increasing the productivity by increasing the concentration of the charged resin, and increasing the pressure during the chlorination reaction. Methods have been proposed.

In order to shorten the reaction time, for example, a method of raising the chlorination reaction temperature is known, and the chlorination is carried out to a temperature exceeding the softening temperature of the starting vinyl chloride resin or the chlorinated vinyl chloride resin during the reaction. By increasing the reaction temperature, the chlorination reaction rate is greatly increased, and productivity is improved by greatly shortening the chlorination reaction time. However,
When the reaction temperature is set to a temperature higher than the softening temperature of the resin, the resin is deteriorated, so that initial coloring during processing cannot be suppressed, and the thermal stability is significantly deteriorated.

In the method of increasing the charged resin concentration,
The reaction time increases, but the production of chlorinated vinyl chloride resin per batch increases more than offsetting it,
Productivity increases. However, as the resin concentration increases, the degree of chlorination of the resin in the reaction vessel becomes non-uniform, so that initial coloring during processing cannot be suppressed, and the thermal stability gradually decreases. Further, the charged resin concentration is 35
If the content is more than 10% by weight, the resin will not be evenly suspended in the aqueous medium even by stirring, and the chlorination reaction cannot be performed uniformly. It cannot be suppressed and the thermal stability is greatly reduced. Therefore, industrially, the resin is produced at an optimum balance point by controlling the concentration of the charged resin to 20 to 35% by weight, which balances the charged amount and the reaction rate.

In the method of increasing the pressure during the chlorination reaction,
By increasing the pressure during the chlorination reaction, the chlorination reaction time is slightly shortened, initial coloring can be suppressed, and improvement in thermal stability is recognized. However, in the photochlorination method, although the risk of damage to the mercury lamp increases, the effect of reducing the reaction time due to the increase in pressure during the chlorination reaction is not so large, and its industrial value is small.

[0008] In the photochlorination method, several proposals have been made regarding the amount of ultraviolet light. For example, Japanese Patent Publication No. 2-41523 describes a method of chlorinating a vinyl chloride resin suspension by irradiating ultraviolet light of about 10 watts per gallon. In the photochlorination method, the amount of ultraviolet light is a general amount of light, and the reaction time is about 8 hours. However, when the amount of ultraviolet light is increased, initial coloring cannot be suppressed, and thermal stability deteriorates remarkably. Despite a demand for improvement in productivity, a reduction in reaction time due to an increase in the amount of ultraviolet light is implemented. Not.

On the other hand, in Japanese Patent Application Laid-Open No. 50-148495, in order to improve the balance between quality and productivity, until the amount reaches 1.6 mol per kg of vinyl chloride resin,
The reaction rate is 0.75 per kg of vinyl chloride resin.
It has been proposed to adjust the amount of UV radiation so that it is in the range of 0.25 mol / hour. As a result, although the quality such as thermal stability is certainly improved, the reaction time is prolonged to 10 to 12 hours, and the productivity is extremely reduced.

[0010]

As described above, when the amount of ultraviolet light is increased, initial coloring cannot be suppressed, and quality such as thermal stability is greatly reduced. It is manufactured at the expense of performance, and improving this balance has been a major industrial issue.

That is, in the present invention, in producing a chlorinated vinyl chloride resin by chlorinating the vinyl chloride resin in an aqueous suspension, it is possible to suppress initial coloring during processing and to sacrifice thermal stability. Another object of the present invention is to provide a method for producing a chlorinated vinyl chloride-based resin which significantly shortens the chlorination reaction time and improves productivity.

[0012]

In view of the above, in a method for producing a chlorinated vinyl chloride resin in which a vinyl chloride resin is chlorinated by supplying chlorine in an aqueous suspension, the relationship between the reaction rate and the quality is examined in detail. As a result, quality deterioration such as initial coloring and thermal stability is not caused by the reaction rate itself, but is caused by insufficient removal of reaction heat and an increase in the temperature of the reaction system. It was found that there was, and the present invention was completed.

That is, the present invention relates to a method for producing a chlorinated vinyl chloride resin in which chlorine is supplied in an aqueous suspension while chlorinating the vinyl chloride resin, wherein the average chlorination reaction rate is 1 kg of the vinyl chloride resin. A method for producing a chlorinated vinyl chloride-based resin having a maximum reaction temperature of 85 ° C. or less per 2 to 4 mol / hour per chlorinated vinyl chloride-based resin. The method for producing a chlorinated vinyl chloride-based resin, wherein the irradiation amount of ultraviolet light is 20 to 60 watts per 1 kg of the vinyl chloride-based resin, The present invention also relates to a method for producing the chlorinated vinyl chloride resin described above, and a chlorinated vinyl chloride resin obtained by each of the above production methods.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a vinyl chloride resin used as a raw material is a homopolymer of vinyl chloride,
Or vinyl chloride and other copolymerizable monomers (eg, ethylene, propylene, vinyl acetate, allyl chloride,
Allyl glycidyl ether, acrylic acid ester, vinyl ether, etc.).

The vinyl chloride resin includes a partially saponified polyvinyl acetate, a dispersant such as methylcellulose and hydroxypropylmethylcellulose, lauroyl peroxide, di-2-ethylhexylperoxy neodecanoate, and t-butyl peroxy neodecanoate. Noate, α,
It is polymerized by suspension polymerization using an oil-soluble polymerization initiator such as α'-azobis-2,4-dimethylvaleronitrile.

In the method for producing a chlorinated vinyl chloride resin according to the present invention, the vinyl chloride resin is chlorinated while supplying chlorine in an aqueous suspension. Here, the concentration of the suspension is preferably 20 to 40% by weight. If the concentration of the suspension is less than 20% by weight, the productivity tends to decrease due to a decrease in the charged capacity. If the concentration exceeds 40% by weight, the viscosity increases sharply and the stirring performance decreases, so that the desired productivity and
Quality tends not to be obtained.

The chlorination reaction is performed at an average reaction rate of 2 to 4 mol / hour per 1 kg of the vinyl chloride resin during the reaction. In order to achieve this average reaction rate, it is possible to use a method of increasing the intensity of ultraviolet light, which is a catalyst for the chlorination reaction, or a method of using an initiator in combination. In particular, chlorination is preferably performed by a method of increasing the intensity of ultraviolet light. This is because, in order to shorten the reaction time in the chlorination reaction, the method of increasing the ultraviolet intensity has a smaller effect on the initial coloring during processing and the thermal stability than the method of greatly increasing the amount of the initiator. Ultraviolet irradiation can be performed by irradiation with a mercury lamp.

If the average reaction rate per 1 kg of the vinyl chloride resin is less than 2 mol / hour, the effect of shortening the chlorination reaction time is insufficient, and if it exceeds 4 mol / hour, the maximum reaction temperature is 85 ° C. Even if it is suppressed below, initial coloring cannot be suppressed, and a decrease in thermal stability is inevitable.

The maximum reaction temperature during the chlorination reaction must be suppressed to 85 ° C. or less, especially to 65 to 85 ° C. When the maximum reaction temperature exceeds 85 ° C., initial coloring cannot be suppressed, and the decrease in thermal stability and the like becomes remarkable.

The chlorination reaction is an exothermic reaction, and the internal temperature rises at an accelerated rate. In order to control the internal temperature, various known heat removal processes can be applied.

The irradiation amount of ultraviolet light is 1 k of vinyl chloride resin.
It is preferably 20 to 60 watts, more preferably 20 to 50 watts per g. Irradiation amount is vinyl chloride resin 1
If it is less than 20 watts / kg, it tends to be difficult to obtain a reaction rate within the range of 2 to 4 mol / hour per kg of the desired vinyl chloride resin. Coloring cannot be suppressed, and thermal stability tends to decrease.

The temperature at the start of the reaction is preferably in the range of 20 to 55 ° C. lower than the glass transition temperature of the vinyl chloride resin, more preferably 35 to 50 ° C. If the temperature at the start of the reaction is lower than 20 ° C., the desired average reaction rate of 2 to 4 mol / hour per 1 kg of the desired vinyl chloride resin tends to be difficult to obtain.
It is difficult to suppress the following, and the initial coloring at the time of processing, which is the object of the present invention, cannot be suppressed, and the thermal stability tends to decrease.

[0023]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples below, but the present invention is not limited to these examples.

In the following Examples and Comparative Examples, parts and percentages are by weight unless otherwise specified.

The methods for measuring or evaluating the initial coloring, thermal stability, and Vicat softening point in Examples and Comparative Examples are as follows. (A) Initial coloring The sheet obtained by kneading with an 8-inch roll at 195 ° C. for 3 minutes and pressing at 200 ° C. for 10 minutes was visually judged for coloring of a 3 mm-thick plate. (B) Thermal stability A sheet obtained by kneading at 195 ° C. for 3 minutes with an 8-inch roll was cut into a length of 3 cm and a width of 5 cm, and the time until blackening after heating in an oven at 200 ° C. was measured. . (C) Vicat softening point According to JIS K 6766. However, the load is 5kg
And

Example 1 35 kg of pure water and 15 kg of a vinyl chloride resin having a polymerization degree of 1000 (manufactured by Kaneka Kogyo Co., Ltd.) were charged into a reactor and subjected to vacuum degassing and nitrogen substitution. Thereafter, chlorine gas was blown in, and a 900-watt high-pressure mercury lamp was irradiated to start the reaction. The temperature at the start of the reaction is 50 ° C.,
The reaction temperature was increased linearly to 5 ° C. After one hour, a chlorination reaction was carried out at a constant temperature of 85 ° C. When the chlorine content of the resin measured by titrating by-produced hydrochloric acid reached 67% by weight, irradiation with a mercury lamp was stopped to stop the chlorination reaction. The reaction time was 1.7 hours. After expelling unreacted chlorine with nitrogen, the remaining hydrochloric acid was removed by washing with water and dried to obtain 17.5 kg of a chlorinated vinyl chloride resin.

With respect to 100 parts by weight of the obtained chlorinated vinyl chloride resin, MBS (Kanebuchi Chemical Industry Co., Ltd.
1) 10 parts by weight, tin-based stabilizer 2 parts by weight, lubricant 1.7
And kneaded with an 8-inch roll at 195 ° C. for 3 minutes. The obtained sheet was pressed at 200 ° C. for 10 minutes to evaluate physical properties. Table 1 shows the evaluation results.

The average reaction rate in Table 1 was calculated by dividing the total number of moles of the substituted chlorine by the weight of the charged vinyl chloride resin and the reaction time.

Example 2 A chlorination reaction was carried out in the same manner as in Example 1 except that the intensity of the high-pressure mercury lamp was changed to 450 watts to obtain 17.5 kg of a chlorinated vinyl chloride resin. The reaction time was 2.3 hours. The obtained chlorinated vinyl chloride resin was blended, kneaded and pressed in the same manner as in Example 1, and the physical properties were evaluated. Table 1 shows the evaluation results.

Example 3 Example 1 was repeated except that the temperature for starting the chlorination reaction was 15 ° C.
A chlorination reaction was carried out in the same manner as in Example 1 to obtain 17.5 kg of a chlorinated vinyl chloride resin. The reaction time was 2.0 hours. The obtained chlorinated vinyl chloride resin was blended, kneaded and pressed in the same manner as in Example 1, and the physical properties were evaluated. Table 1 shows the evaluation results.

Example 4 Example 1 was repeated except that the temperature for starting the chlorination reaction was 60 ° C.
The chlorination reaction was carried out by the method described above to obtain 17.5 kg of a chlorinated vinyl chloride resin. The reaction time was 1.4 hours.
The obtained chlorinated vinyl chloride resin was blended, kneaded and pressed in the same manner as in Example 1, and the physical properties were evaluated. Table 1
Shows the evaluation results.

Comparative Example 1 A chlorination reaction was carried out in the same manner as in Example 1 except that the intensity of the high-pressure mercury lamp was changed to 200 watts to obtain 17.5 kg of a chlorinated vinyl chloride resin. The reaction time was 3.4 hours. The obtained chlorinated vinyl chloride resin was blended, kneaded and pressed in the same manner as in Example 1, and the physical properties were evaluated. Table 1 shows the evaluation results.

Comparative Example 2 A chlorination reaction was carried out in the same manner as in Example 1 except that the intensity of the high-pressure mercury lamp was changed to 1800 watts to obtain 17.5 kg of a chlorinated vinyl chloride resin. The reaction time was 1.1 hours. The obtained chlorinated vinyl chloride resin was used in Example 1.
In the same manner as described above, compounding, kneading, pressing, and physical properties were evaluated. Table 1 shows the evaluation results.

Comparative Example 3 A chlorination reaction was carried out in the same manner as in Example 1 except that the reaction temperature after 1 hour from the start of the reaction was 95 ° C., to obtain 17.5 kg of a chlorinated vinyl chloride resin. The reaction time was 1.2 hours. The obtained chlorinated vinyl chloride resin was blended, kneaded and pressed in the same manner as in Example 1,
Physical properties were evaluated. Table 1 shows the evaluation results.

[0035]

[Table 1]

[0036]

As is clear from the examples and comparative examples, the average reaction rate during the reaction is set within the range of 2 to 4 mol / hour / kg of the vinyl chloride resin and the maximum reaction temperature is suppressed to 85 ° C. or less. By doing so, the initial coloring during processing of the chlorinated vinyl chloride resin can be suppressed, and the reaction time can be shortened and the productivity can be improved without sacrificing thermal stability.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J100 AC03P CA01 CA31 HA27 HB04 HE06 HE12 HE22 HE32

Claims (5)

[Claims] 1. While supplying chlorine in an aqueous suspension,
In the method for producing a chlorinated vinyl chloride resin for chlorinating a vinyl chloride resin, the average chlorination reaction rate is 2 to 4 mol / hour per 1 kg of the vinyl chloride resin, and the maximum reaction temperature is 85 ° C. or less. A method for producing a chlorinated vinyl chloride resin. 2. The method for producing a chlorinated vinyl chloride resin according to claim 1, wherein the chlorination is carried out under irradiation with ultraviolet rays. 3. The method according to claim 1, wherein the irradiation amount of the ultraviolet light is a vinyl chloride resin.
The method for producing a chlorinated vinyl chloride resin according to claim 2, wherein the weight is 20 to 60 watts per kg. 4. The method for producing a chlorinated vinyl chloride resin according to claim 3, wherein the temperature at the start of the reaction is 20 to 55 ° C. 5. A chlorinated vinyl chloride resin obtained by the production method according to claim 1, 2, 3, 4, or 5.