JP2000344830A - Production of chlorinated vinyl chloride resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chlorinated vinyl chloride resin having improved gelation properties and good processability by chlorinating a vinyl chloride resin in the state of an aqueous suspension at a specified temperature under irradiation with ultraviolet rays while the partial pressure of chlorine in the reactor is kept in a range satisfying specified relationships. SOLUTION: The reaction is carried out at 50-100 deg.C while the partial pressure in the reactor is kept in the range satisfying the relationships: 0.5>=P(MPa)>=[T ( deg.C)/140]2-0.03 (wherein T is the reaction temperature; and P is the partial pressure of chlorine). It is desirable that the vinyl chloride resin used is a suspension-polymerized one having a mean particle diameter of 100-200 μm and an average degree of polymerization of 500-2,000. Alternatively, the reaction is performed while hydrogen peroxide is added to the reactor. When hydrogen peroxide is added to the reactor, the partial pressure of chlorine in the reactor is kept in the range satisfying the relationships: 0.7>=P(MPa)>=[T( deg.C)/140]2-0.03. The addition rate of hydrogen peroxide is desirably 5-30 ppm/hr based on the vinyl chloride resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a chlorinated vinyl chloride resin, and more particularly, to a method for producing a chlorinated vinyl chloride resin having excellent processability and heat resistance.

[0002]

2. Description of the Related Art Chlorinated vinyl chloride resin (hereinafter referred to as "CPV")
C) is generally a vinyl chloride resin (hereinafter referred to as “PV
C ") is obtained by post-chlorination.

[0003] CPVC has been used in a wide range of applications because it retains the excellent properties which are said to be the advantages of PVC, and has improved the disadvantages of PVC, such as low heat resistance. That is, since PVC has a low heat distortion temperature, 6
It has a major drawback that it cannot be used at temperatures above 0-70 ° C. In contrast, CPVC has a heat deformation temperature of PV
Since it is 20 to 40 ° C. higher than C and has improved heat resistance, which is a drawback of PVC, it is suitably used for heat-resistant pipes, heat-resistant joints, heat-resistant valves and the like.

However, as described above, the CPVC
Has a higher heat deformation temperature than PVC, so that CPVC must be heated to a high temperature and melted when forming it. However, since CPVC tends to be decomposed and colored when heated, it must be molded at a temperature as low as PVC, despite its high heat distortion temperature. Therefore, there is a problem that the forming process of CPVC is difficult as compared with PVC, it cannot be sufficiently gelled, and the impact strength of the formed body is inferior.

As a method for producing CPVC having excellent processability, for example, JP-A-49-6080 discloses an ionic emulsifier, a water-soluble metal salt and a water-soluble polymer at the stage of polymerizing PVC before chlorination. There is disclosed a method of producing a CPVC having excellent processability by chlorinating PVC composed of aggregates composed of basic particles of about 1 μm by using a suspension stabilizer composed of a dispersant.

In Japanese Patent Application Laid-Open No. 8-104701, it is obtained by using a water-soluble polymer as a suspending agent in the presence of an anionic surfactant insoluble in water and soluble in a vinyl chloride monomer. A method for producing CPVC having excellent processability by chlorinating PVC is disclosed.

[0007] However, these methods are not suitable in terms of practicality and cost, since a special polymerization dispersant must be used when polymerizing PVC before chlorination. .

[0008]

DISCLOSURE OF THE INVENTION In view of the above problems, the present invention is to improve the gelling properties and improve the processability of chlorinated PVC which is generally used.
An object of the present invention is to provide a method for manufacturing PVC.

[0009]

The invention according to claim 1 (hereinafter referred to as the "invention 1") is a method for chlorinating a vinyl chloride resin in a water-suspended state at a reaction temperature of 50 to 100 ° C. and in a reactor. Is characterized in that the chlorination reaction is performed while irradiating ultraviolet rays while maintaining the chlorine partial pressure in the range of the following formula (1). 0.5 ≧ P (MPa) ≧ [T (° C.) / 140] ² −0.03 (1) In the formula, T represents a reaction temperature, and P represents a chlorine partial pressure.

The invention according to claim 2 (hereinafter referred to as invention 2) is characterized in that when chlorinating a vinyl chloride resin in a water suspension state, 5 to 3 hydrogen peroxide is added to the vinyl chloride resin.
While adding at an addition rate of 0 ppm / hour,
The chlorination reaction is carried out at a temperature of up to 120 ° C. and a partial pressure of chlorine in the reactor maintained in the range of the following formula (2). 0.7 ≧ P (MPa) ≧ [T (° C.) / 140] ² −0.03 (2) In the formula, T indicates a reaction temperature, and P indicates a chlorine partial pressure.

Hereinafter, the present invention will be described in detail.

In the production method of the present invention, CPVC is produced by post-chlorinating PVC. The PVC used in the present invention is not particularly limited, and any one produced by any method such as suspension polymerization, emulsion polymerization and bulk polymerization can be used. This is preferable because fine particles can be obtained. As the suspension polymerization method, a conventionally known method is used.

The average particle diameter of the PVC is preferably in the range of 100 to 200 μm from the viewpoint of handleability.
Further, the average degree of polymerization of the PVC is 5 which is suitable for heat molding.
The range of 00 to 2000 is preferred.

The above PVC can be produced, for example, by the following suspension polymerization. First, a vinyl chloride monomer, an aqueous medium, a dispersant, and a polymerization initiator are charged into a polymerization vessel.
At this time, the weight ratio of the aqueous medium / vinyl chloride monomer was 1
To 2 are preferred. Next, the polymerization reaction is performed by raising the temperature to a predetermined reaction temperature. Polymerization rate of vinyl chloride monomer is 7
After reaching a predetermined ratio of 0 to 90% by weight, cooling, exhaust gas, and demonomer treatment are performed to obtain a slurry containing PVC. PVC is obtained by dehydrating and drying the obtained slurry.

It is preferable to use a stainless steel pressure-resistant container equipped with a stirrer, a baffle and a jacket for the polymerization vessel. At this time, a device equipped with a reflux condenser can be used if necessary.

The vinyl chloride monomer means a vinyl chloride monomer alone or a mixture with another monomer copolymerizable with the vinyl chloride monomer. Other monomers copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate; ethylene; And olefins such as propylene; maleic anhydride; acrylonitrile; styrene; vinylidene chloride, and other known monomers, but are not limited thereto.

As the above-mentioned dispersant, those generally used for suspension polymerization of vinyl chloride are preferably used. Such dispersants include, for example, water-soluble celluloses such as methylcellulose, ethylcellulose, hydroxyethylcellulose, and hydroxypropylmethylcellulose; water-soluble polymers such as partially saponified polyvinyl alcohol, polyethylene oxide, acrylic acid polymers, and gelatin; Examples thereof include water-soluble emulsifiers such as laurate and polyoxyethylene sorbitan monolaurate, and these may be used alone or in combination of two or more.

The dispersant is preferably used in an amount of 0.01 to 0.5% by weight based on the weight of the vinyl chloride monomer.

As the above-mentioned polymerization initiator, an oil-soluble initiator generally used for suspension polymerization of vinyl chloride is preferably used. As such a polymerization initiator, for example, di-2
-Ethylhexylperoxydicarbonate, diethoxyethylperoxydicarbonate, α-cumylperoxyneodecanate, t-butylperoxyneodecanate, t-butylperoxypivalate, t-butylperoxy-3 , 5,5-trimethylhexanoe
Acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, lauroyl peroxide, etc., which may be used alone or in combination of two or more. You may use together.

The amount of the polymerization initiator used is preferably in the range of 0.001 to 2% by weight based on the weight of the vinyl chloride monomer.

Furthermore, polymerization regulators, chain transfer agents, pH regulators, antistatic agents, cross-linking agents, stabilizers, fillers, antioxidants, scales commonly used in the polymerization of vinyl chloride monomers. Antioxidants and the like may be added.

In the present invention 1, when chlorinating PVC obtained by the above method in an aqueous medium, first,
After removing oxygen from the container containing the PVC suspension, chlorination is started by introducing chlorine into the container. The PVC may be used as it is without being separated from the aqueous medium, or the PVC may be separated from the suspension and then dispersed again in another aqueous medium. The amount of oxygen in the container after removing oxygen is preferably 100 ppm or less. As chlorine introduced at this time, commercially available chlorine can be used, but in order to obtain CPVC having more excellent thermal stability, an oxygen content of 100 ppm or less is preferable.

The reaction temperature for carrying out the chlorination reaction is 50.
Limited to ~ 100 ° C. If the chlorination reaction is performed at a reaction temperature that is too low, the reaction takes a long time and the productivity decreases, so the reaction temperature is limited to 50 ° C. or higher. In addition, if the reaction temperature is too high, the chlorine partial pressure in the reactor must be increased. Particularly, in the reaction of irradiating ultraviolet rays, since an ultraviolet lamp is provided inside the reactor, The chlorine partial pressure cannot be used at a very high pressure, and is preferably used at 0.5 MPa or less. If the reaction is carried out at a higher chlorine partial pressure than this, an expensive apparatus that can withstand high pressure is required, so that the reaction temperature is limited to 100 ° C. or less. Further, in order to obtain CPVC having good thermal stability, the reaction temperature must be 5
The temperature is preferably from 0 ° C to less than 60 ° C.

In the chlorination reaction, after the temperature is raised to a predetermined reaction temperature, the partial pressure of chlorine in the reactor is maintained within the range of the following formula (1).
This is performed while irradiating ultraviolet rays. 0.5 ≧ P (MPa) ≧ [T (° C.) / 140] ² −0.03 (1) Furthermore, it is preferable to keep the partial pressure of chlorine in the reactor within the range of the following expression (3). . 0.2 ≧ P (MPa) ≧ [T (° C.) / 140] ² −0.03 (3) In the formula, T represents a reaction temperature, and P represents a chlorine partial pressure.

In the above chlorination reaction, when the chlorine content in the CPVC reaches a predetermined weight%, irradiation with ultraviolet rays is stopped, residual chlorine is exhausted, and the reaction is stopped by cooling. The obtained CPVC slurry is washed with water to remove hydrochloric acid. At this time, a neutralizing agent or the like may be added as necessary. Next, the CPVC slurry is dehydrated and dried to obtain a CPVC powder.

Next, the manufacturing method of the second embodiment will be described. In the present invention 2, the chlorination reaction is carried out while adding hydrogen peroxide to PVC. Examples of the PVC include those similar to the PVC used in the first aspect of the present invention.

The reaction temperature for the chlorination is 70 to 12
Limited to 0 ° C. Since the reaction is carried out without irradiation with ultraviolet rays, if the reaction is carried out at an extremely low temperature, the reaction rate is extremely slow even when hydrogen peroxide is added, the reaction takes a long time and the obtained CPVC has poor thermal stability. It will be. Further, when the reaction is carried out at an excessively high temperature, the thermal stability becomes poor, and the chlorine partial pressure in the reactor must be increased, so that expensive reaction equipment is required and the cost is increased. Therefore, the reaction temperature is limited to the above range.

The rate of addition of hydrogen peroxide is limited to 5 to 30 ppm / hour relative to PVC. Addition rate is 5pp
When the rate is less than m / hour, the effect of promoting the chlorination reaction is small and the reaction takes a long time, so that the productivity is reduced.
On the other hand, when the addition rate is higher than 30 ppm / hour, the thermal stability of the obtained CPVC is reduced.

The above chlorination reaction is carried out after raising the temperature to a predetermined reaction temperature, and keeping the partial pressure of chlorine in the reactor within the range of the following equation (2). 0.7 ≧ P (MPa) ≧ [T (° C.) / 140] ² −0.03 (2) In the formula, T indicates a reaction temperature, and P indicates a chlorine partial pressure.

The chlorination reaction is carried out by using the same reactor as in the first embodiment and introducing chlorine in the same manner as in the first embodiment.

In promoting the chlorination reaction by adding the above-mentioned hydrogen peroxide, in order to exert the effect of adding the hydrogen peroxide, continuous or intermittent from the start to the end of the chlorination reaction. Is preferably added immediately after the introduction of chlorine, and more preferably stopped 1 hour to 30 minutes before the end of the reaction.

The hydrogen peroxide may be added in the form of pure hydrogen peroxide, but is preferably added in the form of an aqueous solution.

In the above chlorination reaction, when the chlorine content in the CPVC reaches a predetermined weight percent, residual chlorine is exhausted, cooled, and the reaction is stopped. Then, the obtained C
The PVC slurry is washed with water to remove hydrochloric acid. At this time, a neutralizing agent or the like may be added as necessary. In addition, CPVC
The slurry is dewatered and dried to obtain a CPVC powder.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 200 kg of deionized water and 40 kg of PVC having an average degree of polymerization of 800 were charged into a glass-lined reactor having an internal volume of 300 liters, and the mixture was stirred.
After dispersing C in water, the inside of the reactor was heated to 60 ° C. Next, after the inside of the reactor was evacuated to remove oxygen, chlorine gas was introduced so as to have a chlorine partial pressure of 0.2 MPa, and ultraviolet light was irradiated to start a chlorination reaction. During the chlorination reaction, the reaction temperature is 60 ° C and the chlorine partial pressure is 0.2MP
The chlorination reaction was performed while keeping a constant. When the chlorine content reached 66.5% by weight, the supply of chlorine gas and the irradiation of ultraviolet rays were stopped to terminate the chlorination reaction. Then, nitrogen gas is passed to remove unreacted chlorine, and the obtained CPV
The C slurry was washed with water to remove hydrochloric acid, dehydrated and dried to obtain a powdery CPVC.

(Examples 2 to 4, Comparative Examples 1 to 3) In the same manner as in Example 1 except that the reaction temperature of the chlorination reaction and the partial pressure of chlorine in the reactor were changed as shown in Table 1. A chlorination reaction was performed to obtain CPVC.

Example 5 200 kg of deionized water and 40 kg of PVC having an average degree of polymerization of 800 were charged into a glass-lined reactor having an internal volume of 300 liters, and the mixture was stirred.
After dispersing C in water, the inside of the reactor was heated and heated to 70 ° C. Next, after the inside of the reactor was evacuated to remove oxygen, chlorine gas was introduced so as to have a partial pressure of chlorine of 0.5 MPa, and the temperature was further raised to 100 ° C. During the chlorination reaction, the chlorination reaction was performed while maintaining the reaction temperature at 100 ° C. and the chlorine partial pressure at 0.5 MPa. In addition, from the time when the partial pressure of chlorine in the reactor reaches a predetermined 0.5 MPa to one hour before the chlorine content reaches 66.5% by weight, hydrogen peroxide is added at a rate of 15 ppm / hour to PVC. Was added continuously to accelerate the reaction. 66.5% by weight of chlorine content
When the temperature reached, the supply of chlorine gas was stopped, and the system was cooled to terminate the chlorination reaction. Then, nitrogen gas was passed to remove unreacted chlorine, and the obtained CPVC slurry was washed with water to remove hydrochloric acid, and then dehydrated and dried to obtain a powdery CPVC.

(Examples 6-9, Comparative Examples 4-7) Except that the reaction temperature of the chlorination reaction, the partial pressure of chlorine in the reactor, and the addition rate of hydrogen peroxide were changed as shown in Table 2 A chlorination reaction was carried out in the same manner as in Example 5 to obtain CPVC.

The CPVs obtained in the above Examples and Comparative Examples
The physical properties of C were evaluated as follows, and the results were shown in Tables 1 and 2.
It was shown to. (1) Gel time 100 parts by weight of CPVC, 0.5 parts by weight of butyl stearate, 10 parts by weight of MBS resin, 0.5 parts by weight of MMA resin,
And a formulation 60 comprising 2 parts by weight of a maleic tin stabilizer.
g using a plastmill ("Laboplastmill" manufactured by Toyo Seiki Co., Ltd.) at a rotation speed of 40 rpm and a test temperature of 180.
C., and the time from the start of kneading to the maximum kneading torque was defined as the gel time.

(2) Thermal stability The above composition was fed to two 6-inch variable speed rolls and
The mixture was kneaded at 3 ° C. for 3 minutes to produce a sheet having a thickness of 0.5 mm. This sheet is heated in a gear oven at 210 ° C.
The time (minute) until blackening was measured.

(3) Total porosity and porosity of 0.1 μm or less Using a mercury intrusion porosimeter (manufactured by Carloerba), based on the volume of mercury injected into the resin when pressurized to 200 MPa, And the porosity of 0.1 μm or less were calculated.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

The method for producing CPVC of the present invention is as described above. By chlorinating a generally used PVC, it has excellent thermal stability, is easily gelled, and has good moldability. CPVC can be manufactured efficiently.

Continued on the front page F term (reference) 4J100 AA02Q AA03Q AB02Q AC03P AC24Q AG04Q AK32Q AL03Q AM02Q BB01H CA01 CA04 FA21 FA28 FA29 HA21 HB04

Claims (2)

[Claims] 1. When chlorinating a vinyl chloride resin in a water suspension state, the reaction temperature is 50 to 100 ° C., the chlorine partial pressure in the reactor is maintained in the range of the following formula (1), and the ultraviolet ray is irradiated. A method for producing a chlorinated vinyl chloride resin, which comprises performing a chlorination reaction. 0.5 ≧ P (MPa) ≧ [T (° C.) / 140] ² −0.03 (1) (where T represents the reaction temperature and P represents the chlorine partial pressure, respectively) 2. When chlorinating a vinyl chloride resin in a water suspension state, a reaction temperature of 70 to 120 ° C. is added while adding hydrogen peroxide to the vinyl chloride resin at an addition rate of 5 to 30 ppm / hour. A method for producing a chlorinated vinyl chloride-based resin, wherein the chlorination reaction is carried out while keeping the chlorine partial pressure in the reactor within the range of the following formula (2). 0.7 ≧ P (MPa) ≧ [T (° C.) / 140] ² −0.03 (2) (where T represents the reaction temperature and P represents the chlorine partial pressure, respectively)