JPH0639490B2 - Method for producing easily chlorinated vinyl chloride resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a chlorinated vinyl chloride resin that is easy to process.

(Prior Art) A chlorinated vinyl chloride resin (hereinafter referred to as CPVC) is made by chlorinating a vinyl chloride resin (hereinafter referred to as PVC). CPVC has a property that it is said that PVC has advantages, and is a modified version of the property that PVC has disadvantages. Therefore, it has a possibility of being widely used in various fields in place of PVC. However, CPVC
Has a drawback that it is not easily processed as compared with PVC, and has not been widely used in practice.

This relationship will be described in more detail below. CP
VC retains excellent properties such as water resistance and chemical resistance, which are the advantages of PVC. Since PVC has a low heat distortion temperature, it cannot be used above 60-70 ° C, but CPVC has a heat distortion temperature of 20-4 compared to PVC.
It is only 0 ° C higher and can therefore be used near 100 ° C. So CPVC has heat resistant pipes, heat resistant joints,
It can be used to make heat resistant valves and the like. Also,
Since CPVC is superior to PVC in terms of dimensional stability and flame retardancy, it has recently come to be used for floppy disc jackets, name plates, insulating sheets and the like.

However, if an actual nameplate or insulating sheet is to be made using CPVC, the processing is not easy, which limits the practical use. The reason why it is not easy to process is that CPVC has poor thermal stability and easily decomposes when heated.
Secondly, when trying to knead under heating, CPVC adheres to the metal surface and cannot be easily peeled off from the metal surface. Thermal stability can be improved to some extent by the addition of stabilizers, while release from metal can be improved to some extent by the addition of lubricants. However, none of them could bring about a drastic improvement. Because, in order to give sufficient heat stability and peelability, a large amount of stabilizer and lubricant must be added,
This is because if a large amount of stabilizer or lubricant is added, the properties of CPVC will be deteriorated, for example, the heat distortion temperature of CPVC will be decreased. Therefore, it has been demanded to improve the thermal stability and releasability without deteriorating the properties of CPVC, thereby providing CPVC which is easy to process.

A method for producing CPVC having good thermal stability is disclosed in JP-A-63-
It is disclosed in Japanese Patent No. 122715. This method is characterized by suspension-polymerizing vinyl chloride in the presence of an ethylene-based polymer to produce PVC containing the ethylene-based polymer, and then chlorinating the obtained PVC to obtain CPVC. . However, here, it is necessary to use an ethylene-based polymer having an average molecular weight of 5,000 or less and to use substantially only a cellulose derivative as a dispersant. According to this method, it is possible to obtain CPVC having good thermal stability. However, according to this method, CPVC having good peelability can be obtained.

(Problems to be Solved by the Invention) The present invention has been made in an attempt to provide a CPVC which has good thermal stability, is easily peeled from a metal, and is therefore easy to process. That is, the present invention is intended to provide a CPVC which retains the advantages of the conventional CPVC as it is, and further has good thermal stability and peeling property, and thus is easy to process.

(Means for Solving the Problem) The present inventor has attempted to solve the above-mentioned problems by using CPV.
The property improvement of C was examined from various angles. As a result, the inventor has determined that in the method disclosed in JP-A-63-122715, a propylene-based polymer is used instead of the ethylene-based polymer, and vinyl chloride is added in the presence of the propylene-based polymer. Polymerized and thus obtained PV
When C is chlorinated, CP has surprisingly good peelability.
It was found that VC could be obtained. The result that the peelability is not improved in the presence of the ethylene polymer, but the peelability is improved in the presence of the propylene polymer is a surprising result. The present invention has been completed based on such discoveries and confirmations.

(Summary of the Invention) The present invention is to disperse a propylene polymer powder having an average molecular weight of 10,000 or less and a vinyl chloride monomer in an aqueous medium, and polymerize the vinyl chloride monomer in the dispersed state to produce a propylene polymer. A process for producing a chlorinated vinyl chloride resin, which is easy to process, is characterized in that a vinyl chloride resin containing 0.03 to 3% by weight of the coalescence is made, and then the obtained vinyl chloride resin is chlorinated. To do.

This invention is characterized by the presence of a propylene-based polymer in the step of polymerizing vinyl chloride to make PVC. The propylene polymer needs to have an average molecular weight of 10,000 or less.

The amount of this propylene polymer is 0.03 to 3 parts by weight based on 100 parts by weight of vinyl chloride monomer. Of these, 0.05 to 1.0 part by weight is preferred. This propylene polymer is required to be used as a powder. This is what is required to be evenly dispersed in the vinyl chloride monomer. If the propylene polymer is evenly dispersed in vinyl chloride, the total amount of the propylene polymer is polymerized with the vinyl chloride monomer as it is, and the vinyl chloride resin containing all of the propylene polymer added here is added. can get.

Here, the amount of the propylene polymer is set to 0.03 to 3 parts by weight based on the result of the experiment. That is, when the amount of the propylene polymer is less than 0.03 part by weight, the amount of the propylene polymer is too small and the obtained CPVC does not exhibit satisfactory metal peeling property and thermal stability. Even if the amount of coalescing exceeds 3 parts by weight, 3
This is because the metal releasability and thermal stability are not significantly different from the case where parts by weight are added, and gelation becomes difficult.

The reason why the molecular weight of the propylene-based polymer is limited to 10,000 or less is also based on the result of the experiment. That is, when a propylene-based polymer having a molecular weight of 10,000 or less is used, the CPVC obtained from this shows good metal peelability, but when a propylene-based polymer having a molecular weight of 10,000 or more is used, the CPVC is good. This is because it does not exhibit excellent metal peeling property. The method used by the inventor to determine the average molecular weight is the GPC method, that is, the gel permeation chromatography method.

The propylene-based polymer may contain 20% or less by weight of another monomer. As the other monomer, those having a hydroxyl group, a carboxyl group, a ketone group, or an epoxy group can be used.

In the present invention, an aqueous medium is used in producing PVC, which is a raw material for CPVC, but the aqueous medium in this case is not limited to water. For example, an organic liquid such as methyl alcohol or ethyl alcohol, which can be mixed with water, added to water can be used. In addition, a water-insoluble organic liquid added to water can be used. The water-insoluble organic liquid includes halogenated hydrocarbons such as chloroform and carbon tetrachloride, aromatic hydrocarbons such as benzene and toluene, and ethers such as methyl ethyl ketone and methyl isobutyl ketone.

A dispersant is preferably used to disperse the propylene polymer and the vinyl chloride monomer in the aqueous medium. As the dispersant, various dispersants which have hitherto been used when polymerizing a vinyl chloride monomer in an aqueous medium can be used. Of these, cellulose derivatives are preferred. For example, it is preferable to use cellulose ethers such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose and hydroxypropyl cellulose. These cellulose ethers can be used alone or as a mixture. The amount used may be 0.01 to 2 parts by weight with respect to the monomer to be polymerized.

The order of addition in the aqueous medium is not particularly limited. However, the preferred order is to add the dispersant to the aqueous medium first, then the propylene polymer, and then the vinyl chloride monomer under pressure. At this time, a vinyl chloride monomer is mainly used as a monomer, but a small amount of another monomer copolymerizable with vinyl chloride may be added. In this case, the other monomer is 20% by weight with respect to the vinyl chloride monomer.
Below.

Other monomers include α, such as ethylene and propylene
-Olefins, vinyl esters such as vinyl acetate, vinyl ethers such as cetyl vinyl ether,
Acrylates such as 2-ethylhexyl acrylate and butyl methacrylate, methacrylates, N-substituted maleimides such as phenylmaleimide and cyclohexylmaleimide, vinylidene chloride and the like can be used. In addition, instead of other monomers, for example, in the presence of a polymer such as ethylene-vinyl acetate copolymer,
A graft polymer obtained by graft-polymerizing a vinyl chloride monomer to this may also be used.

A polymerization initiator is used to polymerize the vinyl chloride monomer. As the polymerization initiator, one already known as a catalyst for polymerization of vinyl chloride is used, and this is added according to a known method. More specifically, in the case where the vinyl chloride monomer is to be polymerized by the suspension polymerization method, an oil-soluble polymerization initiator is used, and when the polymerization is performed by the emulsion polymerization method. A water-soluble polymerization initiator is used. Examples of oil-soluble polymerization initiators are benzoyl peroxide, lauroyl peroxide, organic peroxides such as 2-ethylhexyl peroxydicarbonate, and azo compounds such as azobisisobutyronitrile. Examples of water-soluble polymerization initiators are acetyl peroxide, potassium persulfate and the like. The amount of the polymerization initiator, relative to the total amount of monomers to be polymerized,
0.01 to 0.5% by weight.

In this invention, it is desirable to have a chain transfer agent present during the polymerization. As the chain transfer agent, it is preferable to use an oil-soluble one, particularly a mercapto-based compound. That is a fact that can be learned from the results of the experiment. That is, when a mercapto-based compound is present, the obtained product has excellent thermal stability. As the mercapto-based compound, octyl mercaptan, dodecyl mercaptan, mecaptoethanol, octyl thioglycolate, pentaerythritol tetrakis (thioglycolate) and the like give good results. There is no particular limitation on the addition amount of these substances, but it is not limited to 100 parts by weight of the monomer to be polymerized.
It is preferably from 03 to 0.3 parts by weight.

In the present invention, the preferred procedure for producing PVC is
It is as follows. First, an autoclave is used as a container, an aqueous medium is put therein, and then a dispersant and a propylene-based polymer powder are put therein. Then, the inside of the autoclave is deaerated in vacuum to remove oxygen, and then a vinyl chloride monomer is added. Then, a polymerization initiator and a chain transfer agent are added and heated to accelerate the polymerization. In this way, the inside of the autoclave is maintained at a high temperature of a constant temperature for several hours to complete the polymerization.

In the present invention, after the polymerization is completed, the polymer is taken out by a conventional method, and then the obtained polymer is chlorinated by a conventional method. Chlorination can be carried out in suspension, in solution or in solid state. To carry out chlorination in suspension, PVC is dispersed in water and chlorine is chlorinated through chlorine. At this time, it is possible to irradiate with ultraviolet rays to promote chlorination. At this time, a small amount of a ketone such as acetone or methyl ethyl ketone, or a chlorinated hydrocarbon solvent such as chloroform or carbon tetrachloride may be added to the water. Further, hydrochloric acid may be added if necessary. The degree of chlorination is preferably such that the CPVC obtained contains 60-70% by weight chlorine.

(Effects of the Invention) According to the present invention, the propylene polymer powder having an average molecular weight of 10,000 or less, and the vinyl chloride monomer are polymerized in a state where the vinyl chloride monomer is dispersed in an aqueous medium to produce propylene. Make PVC containing 0.03 to 3% by weight of polymer,
Then, the PVC thus obtained is chlorinated to form CPVC, so that the obtained CPVC exhibits good thermal stability when heated, and is easily peeled off from the metal surface, and thus easily processed. It is said. Therefore, it can be processed without using a large amount of heat stabilizer, and can be easily processed without adding a large amount of lubricant. Therefore, a colorless and transparent CPVC molded product can be easily produced. Further, since the CPVC molded product thus obtained retains the good properties of CPVC as it is, the dimensional stability is further improved without compensating for the lack of heat resistance of PVC. Therefore, as an improvement of the drawbacks of PVC, it is said that it has characteristics suitable for wider applications than PVC. The present invention provides a great advantage in providing such an excellent CPVC.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, and in addition, the advantages of the present invention will be specifically described.

In Examples and Comparative Examples, the term "parts" means "parts by weight", and the thermal stability and the metal peeling property shown therein indicate the results measured by the following test method. There is.

First, the thermal stability is determined by adding additives usually used for CPVC processing into a blend, kneading the blend with a heating roll for a certain period of time, and then removing the blend from the roll as a sheet. Was hot-pressed to form a plate, and the degree of coloring of this plate was compared with that of a standard plate to examine the degree of coloring, which was evaluated as thermal stability. More specifically, the formulation was made by mixing the following ingredients in the following proportions:

CPVC 100 parts Reinforcing agent (methyl methacrylate-butadiene-styrene copolymer, Kanebuchi Chemical Co., Kanesu B-11A) 10 parts Stabilizer (octyl tin mercapto, Nitto Chemical Co., TUS # 8831) 1.5 parts Stabilizer (octyltin maleate polymer, manufactured by Nitto Kagaku, TUS # 8813) 0.5 part Lubricant (glycerin monostearate, manufactured by NOF Corporation, Monogly MB) 1.5 parts Lubricant (stearic acid, Kawaken Futaku) Ein Chemical Co., F-3) 1.0 part Add this mixture to an 8-inch roll and roll temperature 190
After kneading at ℃ for 3 minutes, take it out as a sheet, cut it into a certain size, stack the cut pieces, put them in a heat press at 200 ℃ for 7 minutes, pressurize and heat, and then cool. It was taken out as a press plate. The yellowness difference (ΔYI) of this press plate was measured as compared with a standard white plate, and this was evaluated as the initial colorability.

Another method to measure thermal stability is to use the above formulation
62.5 g was weighed, placed in a room kept at 180 ° C., preheated for 3 minutes, and then compounded at a rotor rotation speed of 40 rpm, and the time until the compound was decomposed was measured.

The metal releasability was evaluated by putting the above composition in an 8-inch roll, kneading at 210 ° C., measuring the time until the kneaded product does not peel from the roll surface, and evaluating the length of this time.

Example 1 (Production of PVC) In this example, PVC containing 0.13 parts of a propylene polymer having an average molecular weight of 3000 was used. The details are as follows.

First, in an autoclave, 200 parts of deionized water, 0.08 part of hydroxypropylmethyl cellulose (Metronose 90SH100 manufactured by Shin-Etsu Chemical Co., Ltd.) as a dispersant, and a propylene polymer having an average molecular weight of 3000 were prepared.
0.13 parts was added and the oxygen in the autoclave was removed under reduced pressure, then 100 parts of vinyl chloride monomer and 0.03 part of dilauroyl peroxide (Perloyl L manufactured by NOF CORPORATION) as a polymerization initiator were charged into the autoclave. did.

The autoclave was heated to 64 ° C., the temperature was kept for 6 hours to carry out polymerization, and then immediately cooled to obtain PVC. This PVC had an average degree of polymerization of 800 and contained a propylene polymer in a proportion of 0.2% by weight.

(Production of CPVC) 500 parts of deionized water in an autoclave and the above PVC1
00 parts was added and chlorine gas was passed for 6 hours under irradiation of a mercury lamp to obtain CPVC. This CPVC has a chlorine content of 65
% By weight.

(Evaluation) The obtained CPVC had a difference in yellowness of 28 and was excellent in initial colorability. The decomposition time was 1050 seconds, which was long. Therefore, this CPVC was found to be excellent in thermal stability.

It took 20 minutes until the metal roll could not be peeled off, and it was possible to peel it off over a long period of time.

Example 2 Compared to Example 1, this example was carried out as in Example 1 except that the method of manufacturing PVC was partially modified.

(Manufacture of PVC) The difference from Example 1 is that during the polymerization of PVC,
0.06 parts of n-dodecyl mercaptan was added as a chain transfer agent, the amount of dilauroyl peroxide as a polymerization initiator was increased to 0.06 parts, and the polymerization temperature was slightly lowered to 61 ° C. The only difference is that it has been extended to 7 hours.

Thus, a PVC having an average degree of polymerization of 800 and containing 0.2% by weight of a propylene polymer was obtained.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to obtain CP.
VC was obtained. This CPVC had a chlorine content of 65% by weight.

(Evaluation) The obtained CPVC had a difference in yellowness of 31 and was excellent in initial colorability. The decomposition time was 1,150 seconds, which was long. Therefore, this CPVC was found to have good thermal stability.

The time allowed for peeling from the metal roll was 23 minutes, and therefore the metal peelability was confirmed to be good.

Example 3 This example was carried out as in Example 1 except for a partial change in the method of making PVC as compared to Example 1.

(Production of PVC) The difference from Example 1 was that mercaptoethanol 0.04 part was added as a chain transfer agent, the amount of dilauroyl peroxide was increased as a polymerization initiator to be 0.06 part, and the polymerization temperature was changed. It is only slightly lowered to 61 ° C. and the polymerization time is slightly lengthened to 7 hours.

Thus, a PVC having an average degree of polymerization of 800 and containing 0.2% by weight of a propylene polymer was obtained.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to obtain CP.
VC was obtained. The CPVC had a chlorine content of 65% by weight.

(Evaluation) The obtained CPVC had a difference in yellowness of 28 and was excellent in initial colorability. The decomposition time was 1050 seconds, which was long. The time allowed for peeling from the metal surface was 21 minutes. Therefore, it was recognized that the thermal stability and the metal peeling property were good.

Example 4 This example differs from Example 3 only in that propylene polymers having different average molecular weights are used. Therefore, this example is different from Example 1 only in the manufacturing method of PVC.

(Production of PVC) The difference from Example 1 is that 0.13 parts of a propylene polymer having an average molecular weight of 9,000 is added, 0.04 parts of mercaptoethanol is added as a chain transfer agent, and dilauroyl peroxide is used as a polymerization initiator. Increase the amount of 0.06
The polymerization temperature was slightly lowered to 61 ° C., and the polymerization time was slightly lengthened to 7 hours. Thus, a PVC having an average degree of polymerization of 800 and containing 0.2% by weight of a propylene polymer was obtained.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to give CPV.
I got C. This CPVC had a chlorine content of 65% by weight.

(Evaluation) The obtained CPVC had a yellowness difference of 27, was excellent in initial colorability, and had a decomposition time of 1000 seconds and was stable for a long time. Also, the time allowed for peeling from the metal surface was 22 minutes. Therefore, it was recognized that the thermal stability and the metal peeling property were good.

Comparative Example 1 This Comparative Example differs from Example 1 in that no propylene polymer is used, otherwise Example 1
It carried out exactly like the above.

(Production of PVC) PV having an average degree of polymerization of 800 was carried out in exactly the same manner as in Example 1 except that the propylene polymer was not used.
I got C.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to obtain CPVC having a chlorine content of 65% by weight.

(Evaluation) The obtained CPVC had a yellowness difference of 32 and had good initial colorability, but it was recognized that the decomposition time was short at 600 seconds and therefore the thermal stability was poor. Further, it was recognized that the peelable time from the metal was 16 minutes, which was short, and therefore the metal peeling property was inferior. Therefore, it was recognized that the heat stability and the peeling property were poor and the workability was poor.

Comparative Example 2 In this Comparative Example, the PVC manufacturing process was performed in the same manner as in Comparative Example 1,
PV obtained without using propylene polymer
In the step of chlorinating C, 0.2 part of a propylene polymer having an average molecular weight of 3000 was added and chlorinated to obtain CPVC.

(Production of PVC) PVC having an average degree of polymerization of 800 was carried out in exactly the same manner as in Example 1 except that the propylene polymer was not used.
Got

(Production of CPVC) 100 parts of this PVC and 0.2 part of a propylene polymer having an average molecular weight of 3000 are dispersed in 500 parts of deionized water,
It was chlorinated for 6 hours under irradiation of a mercury lamp to obtain CPVC.
This CPVC had a chlorine content of 65% by weight.

(Evaluation) The obtained CPVC had a difference in yellowness of 34, was inferior in initial colorability, and had a short decomposition time of 850 seconds, and was therefore inferior in thermal stability. Further, it was recognized that the peelable time from the metal roll was 18 minutes, which was short, and therefore the metal peelability was inferior. Therefore, it was judged that the heat stability and the peeling property were poor and the workability was poor.

Comparative Example 3 This Comparative Example was carried out in the PVC production process in the same manner as Comparative Examples 1 and 2 without using a propylene polymer, and the obtained PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. In the process of adding a stabilizer and the like to the obtained CPVC to form a blend, a propylene polymer having an average molecular weight of 3000 was prepared.
Two parts were added and the thermal stability and metal strippability of this formulation was measured.

(Production of PVC) PV having an average degree of polymerization of 800 was carried out in exactly the same manner as in Example 1 except that the propylene polymer was not used.
I got C.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to obtain CPVC having a chlorine content of 65% by weight.

(Evaluation) When a stabilizer, a lubricant and the like were added to this CPVC to form a blend, an extra propylene polymer having an average molecular weight of 3000 was added to 100 parts of CPVC. The thermal stability and metal peeling property of the thus obtained composition were measured.

Although the difference in yellowness was 32, the decomposition time was as short as 600 seconds, so it was recognized that the thermal stability was inferior. Further, the metal peeling property was recognized to be inferior because the peeling time was as short as 18 minutes. Therefore, the workability was recognized to be poor.

Comparative Example 4 This comparative example was carried out in accordance with the teaching of Japanese Patent Application Laid-Open No. 63-122715. That is, in Example 1, an ethylene polymer was used instead of the propylene polymer, and a vinyl chloride monomer was polymerized in the presence of the ethylene polymer to obtain PVC, which was chlorinated to obtain CPVC.

(Production of PVC) A PVC was obtained in the same manner as in Example 1 except that 0.13 parts of an ethylene polymer having an average molecular weight of 4000 was added instead of using the propylene polymer. The obtained PVC had an average degree of polymerization of 800 and contained 0.2% by weight of an ethylene polymer.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to obtain CPVC having a chlorine content of 65% by weight.

(Evaluation) The obtained CPVC had a yellowness difference of 35 and was slightly large, but the decomposition time was as large as 1050 seconds.
The thermal stability was confirmed to be good. However, since the peelable time from the metal was 18 minutes, which was rather short, it was recognized that the metal peeling property was inferior. Therefore, the workability was recognized to be poor.

As described above, the use of the ethylene polymer does not improve the metal releasability, but it is completely unexpected that the use of the propylene polymer improves the metal releasability as in the present invention.

Comparative Example 5 This Comparative Example was carried out by reducing the content of the propylene polymer as compared with Example 1 and outside the range specified by the present invention.

(Production of PVC) The procedure was the same as in Example 1, except that the addition amount of the propylene polymer was reduced and the addition amount of the propylene polymer was 0.013 parts relative to 100 parts of the vinyl chloride monomer. I decided.

The obtained PVC has an average degree of polymerization of 800 and 0.02% by weight.
Of propylene polymer. Therefore, this PVC
Had a propylene polymer content outside the limits specified by the present invention.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to obtain CP.
VC was obtained. This CPVC has a chlorine content of 65% by weight
It was.

(Evaluation) The obtained CPVC was slightly large with a difference in yellowness of 32, and the decomposition time was 700 seconds, which was short, so that it was recognized that the thermal stability was poor. Further, it was recognized that the metal releasability was inferior because the time for peeling from the metal was 16 minutes, which was short. Therefore, it was recognized that the heat stability and the metal peeling property were inferior, and the processability was judged to be inferior.

Example 5 In this example, the amount of propylene polymer added was increased as compared with Comparative Example 5 so that the propylene content was within the range specified by the present invention. Was performed by reducing the addition amount of.

(Production of PVC) The same procedure as in Example 1 was carried out except that the amount of the propylene polymer added was reduced to 100 parts by weight of vinyl chloride monomer.
It was carried out differently in that the added amount of the propylene polymer was 0.07 part.

The obtained PVC had an average degree of polymerization of 800 and contained 0.1% by weight of a propylene polymer.

(Production of CPVC) This PVC was chlorinated in the same manner as in Example 1 to obtain CP.
VC was obtained. This CPVC has a chlorine content of 65% by weight
It was.

(Evaluation) The obtained CPVC had a small yellowness difference of 30 and was small,
Further, the decomposition time was 1000 seconds, which was long, and therefore the thermal stability was confirmed to be good. In addition, since the peelable time from the metal was 20 minutes, which was slightly long, the metal peeling property was confirmed to be good. Therefore, the workability was judged to be good.

Example 6 This example was carried out with varying amounts of propylene polymer added. That is, the propylene polymers used had the same average molecular weight, but the addition amount was made much higher than in Example 1 to carry out.

(Production of PVC) The same procedure as in Example 1 was carried out except that the amount of the propylene polymer added was reduced to 100 parts by weight of vinyl chloride monomer.
The difference was that the amount of propylene polymer added was 1.0 part.

The PVC obtained had an average degree of polymerization of 800 and contained 1.5% by weight of propylene polymer.

(Production of CPVC) The obtained PVC was chlorinated in the same manner as in Example 1,
CPVC was obtained. This CPVC had a chlorine content of 65% by weight.

(Evaluation) The obtained CPVC has a small yellowness difference of 28, which is small.
Further, since the decomposition time was 1200 seconds and it was long, it was confirmed that the thermal stability was good. Further, the time for peeling from the metal was 23 minutes, which was long, and therefore the metal peeling property was confirmed to be good. Therefore, the workability was evaluated as good.

Example 7 In this example, PVC having a low average degree of polymerization was obtained and chlorinated. Therefore, in this example, compared with Example 1, the amounts of the dispersant and the polymerization initiator used were increased, the chain transfer agent was used, the polymerization temperature was increased, the polymerization time was lengthened, and the average degree of polymerization was increased. It was decided to obtain a low PVC.

(Production of PVC) In Example 1, the amount of hydroxypropylmethyl cellulose as a dispersant was increased to 0.12 parts, 0.04 parts of n-dodecyl mercaptan was added as a chain transfer agent, and dilauroyl permeation was used as a polymerization initiator. PV was used in the same manner as in Example 1 except that the amount of oxide used was increased to 0.06 parts, the polymerization temperature was 70 ° C., and the polymerization time was 7 hours.
I got C.

The obtained PVC has an average degree of polymerization of 600 and 0.2% by weight.
Of propylene polymer.

(Production of CPVC) The obtained PVC was chlorinated in the same manner as in Example 1 to obtain C
PVC was obtained. This CPVC had a chlorine content of 65% by weight.

(Evaluation) Although the obtained CPVC had a large yellowness difference of 37,
Since the decomposition time was 1800 seconds, which was a long time, it was confirmed that the thermal stability was good. Further, the time for peeling from the metal was 35 minutes, which was long, and therefore the metal peeling property was confirmed to be good. Therefore, the workability was evaluated as good.

Comparative Example 6 In this Comparative Example, a PVC having a low average degree of polymerization was obtained in the same manner as in Example 7 without using a propylene polymer, and this was chlorinated to obtain CPVC.

(Manufacture of PVC) Based on Example 1, this was carried out with some modifications. The changes were made by increasing the amount of hydroxypropylmethyl cellulose used as a dispersant to 0.12 parts, not using a propylene polymer, and increasing the polymerization temperature to 72 parts.
The same procedure as in Example 1 was carried out except that the temperature was set to ° C. The obtained PVC has an average degree of polymerization of 600.
It was.

(Production of CPVC) The obtained PVC was chlorinated in the same manner as in Example 1 to obtain CPVC. This CPVC had a chlorine content of 65% by weight.

(Evaluation) Since the obtained CPVC had a difference in yellowness of 36, which was rather large, and the decomposition time was 950 seconds, which was short, it was recognized that the thermal stability was inferior. On the other hand, the peelable time from the metal was 24 minutes, which was a long time, and therefore the metal peelability was confirmed to be good. However, since the thermal stability was poor, the workability was evaluated as poor as a whole.

Claims (2)

[Claims] 1. A propylene polymer obtained by dispersing a powder of a propylene polymer having an average molecular weight of 10,000 or less and a vinyl chloride monomer in an aqueous medium, and polymerizing the vinyl chloride monomer in the dispersed state. A process for producing a chlorinated vinyl chloride resin which is easy to process, characterized in that a vinyl chloride resin containing 0.03 to 3% by weight of is prepared and then the obtained vinyl chloride resin is chlorinated. 2. The method according to claim 1, wherein the vinyl chloride monomer is polymerized by adding a mercapto compound as a chain transfer agent to an aqueous medium.