JPH0762020A - Production of chlorinated vinyl chloride resin - Google Patents

Abstract

PURPOSE:To obtain the subject resin providing a molded article having high impact strength, being readily gelatinized, by suspending polyethylene powder having a specific melt index together with a vinyl chloride resin in an aqueous medium, chlorinating the vinyl chloride by introducing a chlorine gas. CONSTITUTION:0.5-2wt.% based on a vinyl chloride resin of polyethylene powder having 0.1-10g/10 minutes melt index and the vinyl chloride resin are dispersed in an aqueous medium such as deionized water into a suspension in a glass lined reactor equipped with a circulation type jacket and oxygen in the reactor is eliminated and sufficiently replaced with nitrogen. At a point of time when the reactor is heated to 125 deg.C, chlorine is introduced into the reactor and the vinyl chloride resin is chlorinated to give the objective high-quality chlorinated vinyl chloride resin which is useful for heat-resistant pipes, heat-resistant joints, heat-resistant valves, etc., is readily gelatinized and provides molded articles having high impact strength.

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, this invention
The obtained chlorinated vinyl chloride resin has a feature that it easily gels without losing the good characteristics of the vinyl chloride resin, and therefore a molded article having high impact strength can be easily produced.

[0002]

2. Description of the Related Art Chlorinated vinyl chloride resin (hereinafter referred to as C
PVC is a vinyl chloride resin (hereinafter referred to as PV
It is made by chlorinating C). CPVC retains the characteristic of PVC as an advantage and improves the characteristic of PVC as a defect. That is, CPVC is a product in which the excellent weather resistance, flame resistance, and chemical resistance of PVC are left as they are, and the disadvantage of PVC that heat resistance is inferior is improved. More specifically, PVC has a low heat distortion temperature and cannot be used for hot water.
The heat distortion temperature of VC is 20-40 ° 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 has poor thermal stability, and when it is heated and gelated, it immediately decomposes and becomes colored. Therefore, CPVC is more difficult to gel by heating than PVC. For this reason, when forming a molded product from CPVC, CPVC was not sufficiently gelled to form a molded product. Therefore, the result is that the molded product of CPVC is inferior in impact strength to PVC. As a result, CPV
C will be limited in its use.

Attempts have therefore been made to increase the thermal stability of CPVC. Attempts to increase thermal stability have been made with C
This was done by adding additives such as stabilizers and lubricants to PVC. Some of the additives increased the thermal stability of CPVC to some extent.
If it is attempted to increase the thermal stability before C can be sufficiently gelled, it is necessary to add a large amount of additive, and as a result, the molded product obtained due to the additive is easily distorted. Occurred. Therefore, depending on this attempt, CP
The impact resistance of the VC molded product could not be improved.

Although no additives are added to CPVC,
A method for improving the thermal stability of CPVC using an ethylene-based polymer is known. This is Japanese Patent Laid-Open No. 63-1227.
No. 15 publication. This publication discloses that in producing PVC, an ethylene polymer having an average molecular weight of 5000 or less is added to an aqueous medium, vinyl chloride is polymerized therein to make PVC, and then this PVC is chlorinated to obtain CPVC. It is described that the obtained CPVC has improved thermal stability. However, this method, which is based on the method of starting CPVC to obtain CPVC, corresponds to the use of a special PVC as a raw material, and thus is not a general method for producing CPVC, and a sufficient effect can be obtained. Has the drawback of being uncommon because of the limitation that only a cellulose derivative must be used as a dispersant.

[0006]

SUMMARY OF THE INVENTION The present invention is an ordinary P
To use CP as a raw material and to make CPVC by chlorinating it so that the obtained CPVC is of good quality and has good impact resistance. It is a thing.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventor made a study from a position different from the conventional one. That is, as described above, the CP
Additives have been added in an attempt to improve the thermal stability of VC, but this approach introduces new drawbacks,
I thought it would not be a fundamental solution. Therefore, the present inventor changed his way of thinking so that CPVC easily gelated when heated.
It was thought that the impact resistance could be improved by providing

The present inventor made an aqueous suspension of PVC, tried to add a small amount of polyethylene powder to this solution and chlorinated it, and further made a molded article using the CPVC thus obtained as a material. Tried. As a result, it has been found that when a specific polyethylene powder is used and added in a specific amount to chlorinate and the chlorination reaction is carried out at a relatively high temperature, CPVC which is easily gelated can be obtained. The present invention has been completed based on such knowledge.

The present invention has a melt index of 0.1.
10 to 10 g / min of polyethylene powder was added to PVC at 0.
At a rate of 5 to 2% by weight, it is dispersed together with PVC in an aqueous medium to form a suspension, and chlorine is blown into the suspension to produce PV.
It relates to a method for producing CPVC, which comprises chlorinating C.

The greatest feature of the present invention is that when PVC is dispersed in an aqueous medium and chlorinated in a suspended state, polyethylene (hereinafter referred to as PE) powder is present in the aqueous medium. PE needs to have a melt index (hereinafter referred to as MI) of 0.1 to 10 g / min. The reason is based on experimental facts. That is, when the MI is less than 0.1 g / min, the obtained CPVC becomes difficult to gel, and conversely 10 g / min.
This is because the impact strength of the obtained CPVC decreases when the amount exceeds the limit. Among them, PE is 0.5-5 g / min M
It is preferable to have I.

The above PE should be added in an amount of 0.5 to 2% by weight based on PVC. The reason is also based on experimental facts. That is, when the amount of PE added is less than 0.5% by weight, the obtained CPVC becomes difficult to gel, and conversely, when the amount added exceeds 2% by weight, the CPVC has a low heat distortion temperature. And
This is because the maximum characteristics of CPVC will be lost.

The PE powder preferably has a particle size in the range of 50 to 200 microns. In order to disperse the PE powder in the aqueous medium, either PE or PVC may be added first, but it is preferable that PE and PVC are premixed and the mixture is dispersed in the aqueous medium. Is.

The present invention, together with the use of PE,
It is characterized in that the chlorination reaction is carried out in a relatively high temperature range of up to 140 ° C. The reason is that the chlorination reaction is 1
This is because it is difficult to sufficiently gelate the obtained CPVC without decomposing it if carried out at a temperature of less than 00 ° C. Conversely, if the chlorination reaction is carried out at a high temperature of more than 140 ° C.,
This is because the obtained CPVC has poor thermal stability. Within the above temperature range, it is preferably 110 ° to 130 ° C.

In order to carry out the chlorination reaction in the above temperature range, the suspension is first heated to the above temperature.
When the chlorination reaction is started, the chlorination reaction is an exothermic reaction, so that heat is generated in the suspension, so that the suspension is cooled and kept at the above temperature.

P used as a raw material in the present invention
The VC may be made by any manufacturing method. For example, a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, or a bulk polymerization method may be used. The PE used as a raw material may be one produced by any manufacturing method, and may be high-density PE or low-density PE.

In chlorination of PVC, it is known to irradiate ultraviolet rays or add a trace amount of oxygen in order to accelerate the chlorination reaction. Also in the method of the present invention, the chlorination reaction may be promoted by irradiating ultraviolet rays or adding a trace amount of oxygen, but irradiation of ultraviolet rays or addition of a trace amount of oxygen is not particularly required.

The matters to be particularly noted in carrying out the method of the present invention are as described above, but other matters are the same as the chlorination of PVC so far. For example, it is preferable to use a glass-lined reaction container equipped with an oil circulation jacket as the reaction container. Also, the chlorination reaction needs to be carried out in the absence of a large amount of oxygen, for that purpose, after putting the suspension in the reaction vessel, the internal air is sucked with a vacuum pump, then nitrogen gas is injected under pressure,
It is preferable to repeat this process to sufficiently remove oxygen and then press-fit chlorine.

In the chlorination process, the concentration of hydrogen chloride in the reaction vessel is measured in the same manner as in the conventional method, the chlorination degree of PVC is calculated, and when the desired chlorination degree is reached, the chlorine supply is stopped,
Residual chlorine is expelled from the reaction vessel, washed with water and dried to remove CPV.
Get C.

[0019]

According to the present invention, polyethylene powder having a melt index of 0.1 to 10 g / min is dispersed in an aqueous medium together with PVC at a rate of 0.5 to 2% by weight based on PVC. As a suspension, chlorine is blown into the suspension to chlorinate PVC to produce CPVC, and thus the obtained CPVC is of high quality having the property of easily gelling when heated. That is, the obtained CP
Despite the fact that VC easily gels, the heat resistance has not deteriorated significantly, and the excellent flame retardancy unique to CPVC,
It has the advantages of weather resistance and chemical resistance. Further, since the obtained CPVC easily gels, it is possible to form a molded product with little coloring by adding a small amount of additives such as a lubricant and a stabilizer. Therefore, the resulting molded product has little distortion and impact strength. It becomes a CPVC molded product with the added advantage of high. Therefore, this CPVC is suitable for making industrial moldings such as heat-resistant pipes, joints and valves. The present invention provides such benefits.

[0020]

EXAMPLES The advantages of the present invention will be specifically described with reference to the following examples and comparative examples. In the following, simply referred to as parts or% means parts by weight or% by weight.

[0021]

Example 1 (Production of CPVC) PVC having an average degree of polymerization of 1050 produced by the suspension polymerization method was placed in a glass-lined reaction vessel equipped with an oil circulation jacket having an internal volume of 300 liters.
30 kg of powder and 300 PE powder with MI of 0.1 g / min
g and 150 kg of deionized water were added and well stirred to form a suspension.

Then, the inside of the reaction vessel was sucked by a vacuum pump, and the internal pressure was kept for 5 minutes under a reduced pressure higher by 20 mm of mercury column than the vapor pressure of water. Then, nitrogen gas was injected under pressure into the reaction vessel. Then, it was again sucked with a vacuum pump and kept under the above reduced pressure for 5 minutes to remove oxygen in the container. During this time, heated oil was passed through the jacket to heat the inside of the container.

When the temperature inside the container reached 125 ° C., chlorine was taken out from the bottom of a commercially available 50 kg liquefied chlorine cylinder, and this chlorine was blown into the reaction container. At the same time as the blowing, cooling oil was flown through the jacket to remove heat generated by chlorination. The chlorination degree of CPVC was calculated from the hydrogen chloride concentration in the container, and the chlorine content was 6
After confirming that the content was 6.5% by weight, the supply of chlorine was stopped and the container was cooled at the same time.

After that, residual chlorine was removed and the chlorination reaction was completed. The product obtained was washed with deionized water, neutralized, dehydrated and dried to give a white CPVC powder.

(Physical property test of CPVC) Obtained CPVC
Was used to make the following formulations: CPVC 100 parts Tribasic lead sulfate 3 Dibasic lead stearate 1 Lead stearate 1 MBS resin 10

1. Preparation of test pieces The above formulation was fed to two 8-inch rolls and
The mixture was kneaded at 0 ° C. for 3 minutes to form a sheet having a thickness of 0.5 mm. This sheet is piled up and 150 kg /
Pressed for 8 minutes under a pressure of ² cm ² and a thickness of 3 mm and 6.
A press plate of 4 mm was obtained. 2. Physical property evaluation The heat distortion temperature was measured using a press plate with a thickness of 6.4 mm, A
Load load 1 according to the method specified in STM D-648
It was measured at 8.6 kg / cm ² . For Charpy impact strength, a press plate with a thickness of 3 mm is used, and JIS K-7111 is used.
The temperature was measured at 23 ° C. according to the method specified in 1. 3. Thermal Stability by Roll Kneading The above composition was kneaded with an 8-inch roll having a surface temperature of 205 ° C., the kneaded product was wound around the roll, and a sheet was cut every 30 seconds from the start of winding and a small amount was cut every 3 minutes. The sheet was cut out, the coloring degree of the sheet was examined, the time when the sheet turned blackish brown was captured, and the thermal stability was shown in the time until then. 4. Gelation temperature measurement by temperature rising plastograph Using a plastomill (R-90) manufactured by Haak,
55 g of the above-mentioned composition was rotated at 40 rpm and the temperature was adjusted to 15
Kneading while raising the temperature from 0 ° C to 5 ° C per minute,
The temperature at which the kneading torque reached its peak was taken as the gelling temperature.

(Test Results) The heat distortion temperature is 106.0 ° C. and the Charpy impact strength is 27.0 kg · cm / cm.
² , the heat stability by roll kneading was 27 minutes, and the gelling temperature by temperature rising plast was 190 ° C. Thus, it was confirmed that this CPVC has a high gelling temperature and a high impact strength despite a low kneading temperature.

[0028]

Example 2 (Production of CPVC) In this example, CPVC having a chlorine content of 66.5% was prepared in exactly the same manner as in Example 1 except that PE having MI of 1 g / min was used. Obtained.

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1, whereupon the heat distortion temperature was 106.5 ° C., the Charpy impact strength was 25.0 kg · cm / cm ² , and the thermal stability by roll kneading was 28 minutes. The gelling temperature due to the temperature rising plast was 188 ° C. Thus, it was confirmed that this CPVC has a high gelling temperature and a high impact strength despite a low kneading temperature.

[0030]

Example 3 (Production of CPVC) In this example, CPVC having a chlorine content of 66.5% was obtained in exactly the same manner as in Example 1 except that PE having an MI of 10 g / min was used.

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1. As a result, the heat distortion temperature was 106.0 ° C., the Charpy impact strength was 24.0 kg · cm / cm ² , and the thermal stability by roll kneading was 28 minutes. Then, the gelling temperature by the temperature rising plast was 185 ° C. Thus, it was confirmed that this CPVC has a low gelling temperature and a high impact strength in spite of a low kneading temperature.

[0032]

Example 4 (Production of CPVC) In this example, CPVC having a chlorine content of 66.5% was obtained in exactly the same manner as in Example 1 except that 150 g of PE having an MI of 1 g / min was used. .

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1. As a result, the heat distortion temperature was 106.5 ° C., the Charpy impact strength was 25.0 kg · cm / cm ² , and the thermal stability by roll kneading was 29 minutes. The gelling temperature due to the temperature rising plast was 190 ° C. Thus, it was confirmed that this CPVC has a high gelling temperature and a high impact strength despite a low kneading temperature.

[0034]

Example 5 (Production of CPVC) In this example, CPVC having a chlorine content of 66.5% was carried out in the same manner as in Example 1 except that 600 g of PE having an MI of 1 g / min was used. Got

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1, whereupon the heat distortion temperature was 105.0 ° C., the Charpy impact strength was 26.0 kg · cm / cm ² , and the thermal stability by roll kneading was 28 minutes. The gelling temperature due to the temperature rising plast was 183 ° C. Thus, it was confirmed that this CPVC has a high gelling temperature and a high impact strength despite a low kneading temperature.

[0036]

Comparative Example 1 (Production of CPVC) In this comparative example, CPVC having a chlorine content of 66.5% was obtained in exactly the same manner as in Example 1 except that PE was not used.

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1, whereupon the heat distortion temperature was 106.5 ° C., the Charpy impact strength was 15.0 kg · cm / cm ² , and the thermal stability by roll kneading was 28 minutes. Then, the gelation temperature by the temperature rising plast was 197 ° C. Thus, it was confirmed that this CPVC had a high gelling temperature and a low kneading temperature resulted in a low impact strength.

[0038]

Comparative Example 2 (Production of CPVC) In this comparative example, MI was 0.05 g.
CPV having a chlorine content of 66.5% in exactly the same manner as in Example 1 except that 300 g of PE / min is used.
I got C.

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1. As a result, the heat distortion temperature was 106.0 ° C., the Charpy impact strength was 17.0 kg · cm / cm ² , and the heat stability by roll kneading was 28 minutes. Then, the gelling temperature by the heated plast was 195 ° C. Thus, it was confirmed that this CPVC had a high gelling temperature and a low kneading temperature resulted in a low impact strength.

[0040]

Comparative Example 3 (Production of CPVC) In this comparative example, Example 1 was used except that 300 g of PE having an MI of 15 g / min was used.
A CPVC having a chlorine content of 66.5% was obtained in exactly the same manner as in.

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1. As a result, the heat distortion temperature was 104.5 ° C., the Charpy impact strength was 14.0 kg · cm / cm ² , and the thermal stability by roll kneading was 28 minutes. Then, the gelling temperature by the temperature rising plast was 185 ° C. Thus, it was confirmed that this CPVC had a low gelling temperature, but a low kneading temperature had a low impact strength.

[0042]

Comparative Example 4 (Production of CPVC) In this comparative example, CPVC having a chlorine content of 66.5% was carried out in the same manner as in Example 1 except that 900 g of PE having an MI of 1 g / min was used. Got

(Test Results) Regarding the obtained CPVC,
Various tests were conducted in exactly the same manner as in Example 1, whereupon the heat distortion temperature was 103.5 ° C., the Charpy impact strength was 22.0 kg · cm / cm ² , and the thermal stability by roll kneading was 25 minutes. The gelling temperature due to the temperature rising plast was 183 ° C. In this way, it was confirmed that this CPVC has a high gel strength and a good kneading temperature despite its low kneading temperature, and is good, but it has a low heat distortion temperature and is not good as a whole.

Claims (1)

[Claims] 1. A melt index of 0.1 to 10 g /
0.5 parts of polyethylene powder to vinyl chloride resin
A chlorinated vinyl chloride, characterized in that it is dispersed in an aqueous medium together with a vinyl chloride resin at a ratio of about 2% by weight to form a suspension, and chlorine is blown into the suspension to chlorinate the vinyl chloride resin. Resin manufacturing method.