JPH08104701A - Production of chlorinated polyvinyl chloride resin - Google Patents

Abstract

PURPOSE: To obtain a chlorinated polyvinyl chloride resin improved in heat resistance maintaining the characteristics inherent in polyvinyl chloride resin and capable of gelling at a relatively low temperature. CONSTITUTION: A vinyl chloride monomer is suspension-polymerized in an aqueous medium in the presence of a suspending agent and an anionic surfactant insoluble in water an soluble in the vinyl chloride monomer to make a polyvinyl chloride resin, and this resin is chlorinated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a chlorinated vinyl chloride resin. In particular, the present invention relates to a method for producing a chlorinated vinyl chloride resin, which is characterized in that the obtained chlorinated vinyl chloride resin is easy to gel and is easy to process.

[0002]

2. Description of the Related Art Chlorinated vinyl chloride resin (hereinafter referred to as CPVC) is made by chlorinating vinyl chloride resin (hereinafter referred to as PVC). CPVC is PV
The property called C's advantage is left, and the property called a defect of PVC is improved. That is, CPV
C is an improved version of PVC's disadvantage of poor heat resistance, while retaining the excellent weather resistance, flame resistance, and chemical resistance of PVC. More specifically, PVC has a low heat distortion temperature and has a usable upper limit temperature of 60 to 70 ° C.
Because it is in the vicinity, it can not be used for hot water,
The heat distortion temperature of CPVC is 20 to 40 ° C. higher than that of PVC, and it can be used for hot water. Therefore, CPVC is suitable for making heat resistant pipes, heat resistant joints, heat resistant valves and the like.

As mentioned above, CPVC has a higher heat distortion temperature than PVC. Therefore, in order to process CPVC into a molded body, it must be heated to a temperature higher than that of PVC to cause gelation. However, CPVC easily decomposes when heated to a high temperature, and therefore tends to decompose and become colored when it is heated and gelated. Therefore, CPVC is more difficult to gel by heating than PVC. Therefore, when a molded product is made from CPVC, the molded product is one in which CPVC is not sufficiently gelled. For this reason, CPVC molded products are PV
The result is that the impact strength is inferior to that of C. As a result, CPVC has become less available. Therefore, it has been desired to improve the gelling properties of CPVC so that it can be gelled by heating to a lower temperature.

[0004]

The present invention was made in response to the above-mentioned demand. That is, the present invention intends to provide a CPVC that retains the excellent properties of PVC as they are, has a significantly improved gelling property, and can be sufficiently gelled by heating to a relatively low temperature. To do.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the inventor made an in-depth examination in the stage of manufacturing PVC. As a result, when PVC is produced, suspension polymerization is carried out using a special suspending agent, and if the PVC thus obtained is chlorinated by a conventional method, the obtained CPVC tends to gel at a low temperature. Found. It has been found that it is effective to use, as the suspending agent, an anionic surfactant which is not soluble in water but soluble in the vinyl chloride monomer. Since all the surfactants that have been used for suspension polymerization of PVC have been soluble in water, it is novel to carry out suspension polymerization using a surfactant that is insoluble in water. It is quite surprising that this improves the gelling properties of CPVC. The present invention has been completed based on such knowledge.

The present invention uses a water-soluble polymer as a suspending agent in the presence of an anionic surfactant which is soluble in a vinyl chloride monomer but not in water, and the vinyl chloride monomer is used as an aqueous medium. A polymerization initiator that is suspended in the vinyl chloride monomer and dissolved in the vinyl chloride monomer is added, and the vinyl chloride monomer is polymerized to produce PV.
The gist is a method for producing CPVC, which is characterized by producing C and then chlorinating the PVC.

The present invention is roughly divided into two steps. The previous process is to make PVC. The subsequent step is a step of chlorinating PVC to CPVC. This invention differs from conventional methods in the process of making PVC, and PVC made by a unique method
Is characterized in that it is subjected to chlorination, and the chlorination process does not differ from the conventional method.

Therefore, the manufacturing process of PVC according to the present invention will be described first. The manufacturing process of PVC follows the conventional suspension polymerization method. However, as the suspending agent, it is necessary to select and use a water-soluble polymer from the suspending agents that have been used so far, and further, it is used as a suspending agent in the suspension polymerization of PVC until now. It is necessary to use a suspension that has never been used. A suspending agent that has never been used is an anionic surfactant that dissolves in the vinyl chloride monomer but not in water.

In the PVC manufacturing process of the present invention,
At least two suspending agents are used. One of them is a conventionally used water-soluble polymer. Therefore, first of all, this water-soluble polymer will be classified into a cellulose derivative and a synthetic polymer, and it is sufficient to use at least one of them. As the cellulose derivative, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, hydroxyethyl cellulose and the like can be used in addition to the above-mentioned methyl cellulose and carboxymethyl cellulose. As the synthetic polymer, in addition to the above-mentioned polyvinyl alcohol and partially saponified polyvinyl alcohol, a special saponification polyvinyl alcohol having a degree of saponification of 60 to 80 containing 0.02 to 5 mol% of a sulfuric acid ester or a phosphoric acid ester. Mol% modified polyvinyl alcohol, 0.0
Modified polyvinyl alcohol having a saponification degree of 60 to 90 mol% and vinyl acetate containing 2 to 10 mol% of anionic hydrophilic groups such as carboxylic acid groups and sulfonic acid groups and 0.01 to 5 mol% of hydrophobic groups. Maleic acid copolymer, polyvinylpyrrolidone, polyacrylic acid salt, high molecular weight polyethylene glycol, polypropylene glycol and the like can be used. It is suitable to use sodium polyacrylate or potassium polyacrylate as the polyacrylate.

In the PVC manufacturing process of the present invention,
The most notable feature is the use of an anionic surfactant that dissolves in the vinyl chloride monomer but does not dissolve in water as the suspending agent. Examples of such a surfactant include a low-sulfated oil having a reduced number of hydrophilic groups, a petroleum sulfonate having an extremely large hydrophobic group, an amine salt having a counterion selected to be oil-soluble, and a water-insoluble agent. A metal salt or the like can be used. The details of these are as follows.

The low-sulfated oil having a reduced number of hydrophilic groups is
For example, among the sulfated oils called funnel oil, the amount of bound sulfuric acid / total fat in the range of about 5% to at most 10% corresponds to this. The petroleum sulfonate having an extremely large hydrophobic group is, for example, a straight chain sodium alkylbenzene sulfonate having 12 or more, preferably 20 or more carbon atoms. The water-insoluble metal salt is, for example, a barium or calcium salt of alkylbenzene sulfonic acid.

[0012]

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[0013] Of the anionically active surfactants sold by Moresco under the name Thulhol, the oil-soluble ones can be used in the process according to the invention.

The above water-soluble polymer is preferably used in an amount of 0.005 to 0.2% by weight, more preferably 0.01 to 0.1% by weight based on the vinyl chloride monomer. It is suitable. Further, the above-mentioned water-insoluble and vinyl chloride-soluble anionic surfactant has a ratio of 1 to vinyl chloride monomer.
It is suitable to use ~ 200ppm, and among them 10 ~
It is more preferable to use it in the range of 100 ppm. The reason is that when the amount of the above anion activator is within the range of 1 to 200 ppm, the processability of CPVC becomes good, but when the amount of the above anion activator is less than 1 ppm, the effect of addition does not appear. On the contrary, if it exceeds 200ppm, PV will be obtained.
This is because the particles of C become too large and the polymerization reaction does not proceed smoothly, so that good results cannot be obtained.

In the PVC manufacturing process of the present invention,
An aqueous medium is used as the medium for carrying out the suspension polymerization. Deionized water is preferred as the aqueous medium. The amount ratio of vinyl chloride to the aqueous medium is the same as the conventionally used range, but it is suitable that the range is generally from 1: 1 to 1: 3.

In the PVC manufacturing process of the present invention,
A polymerization initiator is used to carry out suspension polymerization, but the polymerization initiator needs to be one that is soluble in the vinyl chloride monomer. The polymerization initiator has hitherto been used for suspension polymerization of vinyl chloride. Examples are organic peroxides such as lauroyl peroxide, α-cumylperoxy neodecanoate, t-butylperoxy neodecanoate, and 2,2′-azobisisobutyronitrile. Is an azo compound such as.

The PVC production process of the present invention can be applied not only to the case where only vinyl chloride is used as a monomer, but also to the case where a mixture of vinyl chloride and another monomer is used. As other monomers, ethylene, propylene, vinyl acetate, alkyl vinyl ether, acrylic acid and methacrylic acid, and esters thereof can be used.

The PVC production process in the present invention is carried out in the same manner as the conventional suspension polymerization except that the above-mentioned special one is used as the suspending agent. That is, an autoclave is used as a container, first an aqueous medium such as deionized water is put therein, and then a suspending agent is added thereto and dissolved by stirring. After adding a vinyl monomer and dispersing the monomer in an aqueous medium to make a suspension, a polymerization initiator is added to this. The autoclave is then heated and the contents are maintained at elevated temperature for several hours to allow the monomers to polymerize. When the polymerization proceeds and the pressure of the monomer in the autoclave decreases, the autoclave is cooled to lower the temperature of the content, unreacted monomer is recovered, and the content is taken out.
It is then dehydrated and dried to obtain PVC.

In the present invention, the PVC obtained as described above is then chlorinated. The chlorination step can be performed by directly following the conventional method. That is, the chlorination can be carried out in a state in which PVC is suspended, a state in which it is dissolved in a solvent to form a solution, or a solid state. Chlorination is performed by contacting PVC with chlorine.

Among them, when chlorinating in suspension,
Chlorination can be carried out by directly blowing chlorine into the suspension itself obtained by suspension polymerization without separating the PVC obtained by suspension polymerization from the aqueous medium. Alternatively, after the PVC is separated from the above suspension, the PVC can be dispersed again in another aqueous medium, and chlorine can be blown into the dispersion for chlorination. At this time, it is preferable to irradiate ultraviolet rays to promote chlorination. Further, a small amount of ketones such as acetone and methyl ethyl ketone may be added to the aqueous medium, and if necessary, a small amount of chlorine-based solvent such as hydrochloric acid, trichlorethylene and carbon tetrachloride may be added.

In the chlorination step in the present invention, it is preferable that the CPVC obtained has a chlorine content of 60 to 70% by weight.

[0022]

According to the method of the present invention, a water-soluble polymer is used as a suspending agent in the presence of an anionic surfactant which is insoluble in water but is soluble in a vinyl chloride monomer. It was obtained by suspending the monomer in an aqueous medium, adding a polymerization initiator that dissolves in the vinyl chloride monomer, polymerizing the vinyl chloride monomer, and chlorinating the PVC thus obtained. CPVC is suitable for processing, yet has good thermal stability and low gelation temperature, and is therefore easy to process.

[0023]

[Examples] Hereinafter, the reason why the method of the present invention is excellent will be specifically described by giving Examples and Comparative Examples. In the examples and the comparative examples, “parts” simply means “parts by weight”. Further, there, physical properties such as gelation temperature, thermal stability and heat distortion temperature of the obtained CPVC are measured, and the measuring method is as follows.

First, a mixture having the following ratio was prepared for measuring the physical properties. CPVC 100 parts Tribasic lead sulfate 3 Dibasic lead stearate 1 MBS resin 10

Gelation temperature Using a Haak Plastomill R-90, 55 g of the above formulation was rotated at 40 rpm and the temperature was 150 ° C.
Kneading was performed while increasing the temperature at a rate of temperature increase of 5 ° C./min, and the temperature at which the kneading torque reached its peak was taken as the gelling temperature.

Thermal Stability The above composition was fed to a kneader composed of two 8-inch rolls, kneaded at a surface temperature of the roll of 205 ° C., and the kneaded product was wound around the roll. While turning back the CPVC sheet wound every 30 seconds from the start of winding, cut out a small amount of sheet every 3 minutes and compare the coloring degree of the sheet,
It showed thermal stability at the time when it turned blackish brown.

Heat distortion temperature The above composition was fed to a kneader consisting of two 8-inch rolls and kneaded at 190 ° C. for 3 minutes to obtain a sheet having a thickness of 0.5 mm. The sheets were stacked and press-molded at a temperature of 195 ° C. and a pressure of 150 kg / cm ² for 8 minutes to form a press plate having a thickness of 6.4 mm. Using this pressed plate as a test piece, the heat distortion temperature was measured under a load of 18.6 kg / cm ² according to ASTM D648.

[0028]

Example 1 (Production of PVC) In this example, partially saponified polyvinyl alcohol and hydroxypropyl methylcellulose were used as a suspending agent composed of a water-soluble polymer, and dissolved in vinyl chloride monomer without being dissolved in water. Sodium eicosylbenzene sulfonate was used as a suspending agent consisting of an anionic surfactant. The details of the implementation are as follows.

An autoclave having an internal volume of 216 liters was charged with 143 parts of deionized water, and then as a suspending agent, a partially saponified polyvinyl alcohol having a saponification degree of 72 mol% 0.05
Parts and hydroxypropyl methylcellulose 0.03 parts,
After adding 0.005 parts of sodium eicosylbenzenesulfonate and removing the oxygen in the autoclave under reduced pressure, 100 parts of vinyl chloride monomer and 0.017 part of α-cumylperoxy neodecanoate as a polymerization initiator were added. , T-butyl peroxy neodecanoate 0.06 part was added.

The contents are heated to 58 ° C. by heating the autoclave.
Polymerization is carried out while maintaining the temperature of
When the amount reached g / cm ² , unreacted vinyl chloride monomer was recovered, the contents were taken out, dehydrated to obtain PVC, and dried. The PVC thus obtained has a polymerization yield of 85.
%Met. The average degree of polymerization of this PVC was 1000.

(Production of CPVC) 500 parts of deionized water and 100 parts of the above-obtained PVC were placed in a glass-lined reaction tank having an internal volume of 300 liters, and the mixture was stirred to produce PVC.
Is dispersed in water and then the reaction tank is heated to 70
It was kept at ℃. Then, nitrogen gas was blown into the reaction tank to replace the inside of the tank with nitrogen gas. Then, chlorine gas was blown into the reaction tank, and the inside of the tank was irradiated with ultraviolet rays by a mercury lamp to chlorinate PVC. The chlorination reaction is continued while measuring the concentration of hydrochloric acid in the tank and examining the progress of the chlorination reaction, and the supply of chlorine gas is stopped when the chlorine content of the CPVC produced reaches 68.5% by weight. The chlorination reaction was completed.

Thereafter, nitrogen gas was blown into the tank to remove unreacted chlorine, the obtained dispersion was neutralized with sodium hydroxide, washed with water, dehydrated and dried to obtain a powdered CPVC.
I got

The chlorine content of the obtained CPVC is 68.5.
% By weight, gelling temperature 190 ° C., thermal stability 28
The heat distortion temperature was 138 ° C. This CPVC is
Compared with CPVC of Comparative Example 1 described later, the gelling temperature was low and the processing was easy.

[0034]

Comparative Example 1 Example 1 is the same as Example 1 except that sodium eicosylbenzene sulfonate is not used.
It carried out exactly like the above.

The chlorine content of the obtained CPVC is 68.5.
% By weight, gelling temperature was 202 ° C., thermal stability was 25 minutes and heat distortion temperature was 137 ° C.

Comparing the CPVC obtained in Example 1 with the CPVC obtained in Comparative Example 1, both differ only in whether or not sodium eicosylbenzene sulfonate is used in the production process, and the chlorine content is different. Is the same 68.5
% By weight, and heat distortion temperatures of 138 ° C. and 13
It is almost the same value of 7 ℃, and the thermal stability is 28 each.
Although they are 25 minutes and 25 minutes, there is no big difference, but both show a large difference in gelation temperature of 190 ° C. and 202 ° C., which is 12 ° C. This makes it clear that the effect of sodium eicosylbenzene sulfonate is remarkable.

[0037]

Example 2 In the production of CPVC of Example 1, CP
The same operation as in Example 1 was performed except that the supply of chlorine gas was stopped when the chlorine content of VC reached 66.5% by weight.

Therefore, in this example, the chlorine content of CPVC was 66.5% by weight. The gelling temperature of this CPVC was 172 ° C, the thermal stability was 22 minutes, and the heat distortion temperature was 106 ° C. This CPVC had a low gelation temperature and was easy to process as compared with the CPVC obtained in Comparative Example 2 below.

[0039]

Comparative Example 2 Example 2 was repeated except that sodium eicosylbenzene sulfonate was not used in Example 2.
It carried out exactly like the above.

Therefore, the chlorine content of the obtained CPVC is 66.5% by weight. The gelling temperature of this CPVC is 1
The temperature was 88 ° C, the thermal stability was 21 minutes, and the heat distortion temperature was 104 ° C.

Comparing the CPVC obtained in Example 2 with the CPVC obtained in Comparative Example 2, they differ only in whether or not sodium eicosylbenzenesulfonate is used in the production process, and the chlorine content is Are the same 66.5
% By weight, and heat distortion temperatures of 106 ° C. and 10
It is almost the same value of 4 ℃, and the thermal stability is 22 minutes and 21 minutes.
The gelation temperatures are 172 ° C. and 188 ° C., which are almost the same, but 16 ° C., which is a large difference. This clearly shows that the effect of sodium eicosylbenzene sulfonate is remarkable.

[0042]

Example 3 In this example, calcium dodecylbenzene sulfonate was used as an anionic surfactant insoluble in water and soluble in vinyl chloride monomer. In detail,
In Example 1, the amount of partially saponified polyvinyl alcohol used was increased to 0.06 parts, and the amount of hydroxymethyl cellulose used was reduced to 0.02 parts. Sodium eicosylbenzenesulfonate was replaced with calcium dodecylbenzenesulfonate. Using 0.01 part,
CP was carried out in the same manner as in Example 1 except that polymerization was performed.
VC was obtained.

The CPVC obtained has a chlorine content of 68.5% by weight, the gelling temperature is 184 ° C.,
The thermal stability was 27 minutes and the heat distortion temperature was 140 ° C. This CPVC is the CPVC obtained in Comparative Example 1 above.
Compared with, the gelling temperature was low and it was easy to process.

[0044]

Example 4 In Example 1, the amount of partially saponified polyvinyl alcohol used was increased to 0.08 parts, and the amount of hydroxymethyl cellulose was decreased to 0.01 parts. Dodecylbenzene was used instead of sodium eicosylbenzenesulfonate. The procedure of Example 1 was repeated except that 0.002 parts of barium sulfonate was used.

The CPVC obtained had a chlorine content of 68.5% by weight, a gelling temperature of 180 ° C., a thermal stability of 30 minutes and a heat distortion temperature of 136 ° C. This CP
VC is CP indicating chlorine content and heat distortion temperature as described above
Among the VCs, the gelling temperature was low and the processing was easy.

[0046]

Example 5 In Example 1, the amount of partially saponified polyvinyl alcohol used was reduced to 0.04 parts, the amount of hydroxymethyl cellulose was increased to 0.04 parts, and the amount of sodium eicosylbenzene sulfonate was reduced. 0.0
The same procedure as in Example 1 was carried out except that the amount was set to 01 part.

The CPVC obtained had a chlorine content of 68.5% by weight, a gelling temperature of 170 ° C., a thermal stability of 28 minutes and a heat distortion temperature of 137 ° C. This CP
VC is CP indicating chlorine content and heat distortion temperature as described above
Among the VCs, the gelling temperature was low and the processing was easy.

[0048]

Example 6 In Example 1, 0.05 parts of the partially saponified polyvinyl alcohol having a saponification degree of 72% used in Example 1 and 0.03 part of a saponification degree of 50% were used. Except for the above, the same procedure as in Example 1 was performed.

The CPVC obtained had a chlorine content of 68.5% by weight, a gelling temperature of 155 ° C., a thermal stability of 28 minutes and a heat distortion temperature of 142 ° C. This CP
VC is CP indicating chlorine content and heat distortion temperature as described above
Among the VCs, the gelling temperature was low and the processing was easy.

[0050]

Example 7 The procedure of Example 1 was repeated except that hydroxymethyl cellulose was not used and the amount of partially saponified polyvinyl alcohol was increased to 0.07 part.

The CPVC obtained had a chlorine content of 68.5% by weight, a gelling temperature of 180 ° C., a thermal stability of 26 minutes and a heat distortion temperature of 140 ° C. This C
PVC is C which shows the chlorine content and heat distortion temperature as described above.
Among PVC, it had a low gelation temperature and was easy to process.

[0052]

Example 8 The procedure of Example 1 was repeated except that the partially saponified polyvinyl alcohol was not used and the amount of hydroxymethyl cellulose used was increased to 0.07 part.

The CPVC obtained had a chlorine content of 68.5% by weight, a gelation temperature of 182 ° C., a thermal stability of 28 minutes and a heat distortion temperature of 139 ° C. This C
Among the CPVCs having the above chlorine content and heat distortion temperature, PVC had a low gelation temperature and was easy to process.

[0054]

COMPARATIVE EXAMPLE 3 The procedure of Example 1 was repeated except that sodium eicosylbenzenesulfonate was not used and 0.005 parts of sodium dodecylbenzenesulfonate was used instead. .

The above-mentioned sodium dodecylbenzene sulfonate is soluble in water. Therefore, the vinyl chloride monomer could not be polymerized and PVC could not be obtained.

[0056]

Comparative Example 4 In Example 1, 0.05 parts of the partially saponified polyvinyl alcohol used in Example 1 having a saponification degree of 72% and 0.03 part of a saponification degree of 50% were added. The same procedure as in Example 1 was carried out except that sodium eicosylbenzenesulfonate was not used.

The CPVC obtained had a chlorine content of 68.5% by weight, a gelling temperature of 196 ° C., a thermal stability of 26 minutes and a heat distortion temperature of 140 ° C. This C
The PVC had a higher gelation temperature than any of the CPVCs obtained in the examples.

Claims (1)

[Claims] 1. A water-soluble polymer is used as a suspending agent in the presence of an anionic surfactant that dissolves in a vinyl chloride monomer without being dissolved in water, and the vinyl chloride monomer is used in an aqueous medium. It is characterized by suspending and adding a polymerization initiator that dissolves in a vinyl chloride monomer, polymerizing the vinyl chloride monomer to make a vinyl chloride resin, and then chlorinating the vinyl chloride resin. , A method for producing a chlorinated vinyl chloride resin.