JP2002308930A - Method for manufacturing chlorinated vinyl chloride- based resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a chlorinated vinyl chloride-based resin which permits easy removal of hydrogen chloride and gives a molded product low incoloring. SOLUTION: The vinyl chloride-based resin, obtained by suspension polymerizing a vinyl chloride monomer using a specific amount of a partially saponified polyvinyl acetate and at least one dispersant selected from dispersants other than the partially saponified polyvinyl acetate in the presence of an oil-soluble polymerization initiator, is subjected to a post-chlorination reaction with chlorine in a gas-solid contacting site.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a vinyl chloride resin produced by a specific method is reacted with chlorine in a gas-solid contact field, so that post-treatments such as washing, drying and waste liquid treatment are easy. This is a technique for producing a chlorinated vinyl chloride resin with less coloring of a molded product.

[0002]

2. Description of the Related Art A chlorinated vinyl chloride resin obtained by post-chlorination of a vinyl chloride resin has excellent heat resistance, flame retardancy,
It has mechanical strength and electrical properties and is used in various industries. For example, the glass transition temperature of a normal vinyl chloride resin is about 80 ° C., but the glass transition temperature of a chlorinated vinyl chloride resin increases with an increase in the chlorine content,
Reaches 120-130 ° C. The Vicat softening temperature also shows a high value of about 120 ° C. Due to such high heat resistance, chlorinated vinyl chloride resins are used for heat-resistant pipes, heat-resistant joints, heat-resistant valves, heat-resistant sheets and the like.

[0003] An industrial production method of a chlorinated vinyl chloride resin is a step of polymerizing a vinyl chloride monomer by a suspension polymerization method to obtain a vinyl chloride resin, and post-chlorinating the vinyl chloride resin. It consists of two steps. In the former suspension polymerization step, a method using a suspending agent mainly composed of partially saponified polyvinyl acetate as the suspending agent is generally used.

On the other hand, in the latter post-chlorination step, a water suspension chlorination method has been mainly used. In the water suspension chlorination method, a water suspension of a vinyl chloride resin having a solid content concentration of several% to several tens% is filled in a reaction vessel, and chlorine is supplied to the stirred water suspension to perform a reaction. How to do. Furthermore, since the chlorination reaction does not proceed at all or is very slow by itself, light, heat, a catalyst, etc. are added to the aqueous suspension to promote the reaction.
In the water suspension chlorination method, particles are easily stirred and mixed, the reaction control is easy because low-concentration chlorine dissolved in water is used, and vinyl chloride resin is plasticized with water. There are various advantages such as that chlorine easily penetrates into the resin. For this reason, the water suspension chlorination method has been employed in many of the production facilities for chlorinated vinyl chloride resins that have been put into practical use.

[0005] However, the water suspension chlorination method has a problem which cannot be essentially solved. In a reaction in which a chlorinated vinyl chloride-based resin is generated from a vinyl chloride-based resin and chlorine, hydrogen chloride is generated as shown in Equation (2). Therefore,
After completion of the reaction, the chlorinated vinyl chloride resin is suspended in a high-concentration hydrochloric acid solution.

[0006]

Embedded image The final shipping form of the chlorinated vinyl chloride resin must be in powder form, and it is necessary to remove hydrogen chloride as an impurity. The suspension must be dewatered, washed and dried. For this reason, the process of the water suspension chlorination method requires a large equipment cost for the post-treatment step, and the running cost associated with drying and washing with water increases. Moreover, since water and hydrogen chloride are in an azeotropic state, hydrogen chloride cannot be removed from the product until it is finally completely dried.

In the water suspension chlorination method, at the end of the reaction, the reaction solution becomes a high concentration hydrochloric acid solution of about 10% by weight. For this reason, in the water suspension chlorination method, it is necessary to use a titanium-based or titanium-palladium-based expensive corrosion-resistant metal material for the reaction apparatus, or use an apparatus having a surface treatment such as glass lining or fluorine lining. is there. Further, since the reaction solution having a high concentration of hydrochloric acid is carried into the above-mentioned post-treatment step, it is necessary to use an expensive corrosion-resistant material also in the post-treatment step.

As described above, the reactor for the water suspension chlorination method is
Although it is a device that is relatively simple in itself and easy to control, considering the entire process including the post-processing steps,
The apparatus has a disadvantage that a large load is imposed on equipment costs and running costs.

On the other hand, in order to make up for such a drawback of the water-suspended chlorination method, a chlorine-containing chlorination method using a gas-solid contact chlorination method using a gas-solid contact field between powder particles of a vinyl chloride resin and chlorine as a reaction field. A method for synthesizing a vinyl chloride resin has also been proposed. In the gas-solid contact chlorination method, the generated hydrogen chloride is discharged from the system as a gas, so the hydrogen chloride remaining after the reaction is adsorbed on the surface of the powder particles as well as those existing in the gaps between the powder particles. Hydrogen chloride only. Such residual hydrogen chloride can be easily removed by degassing the inside of the system in a vacuum or by circulating a gas such as air or nitrogen to wash the air. Therefore, water-washing /
A product having a low residual hydrogen chloride content as an impurity can be obtained without going through complicated steps such as dehydration and drying.

Further, in the gas-solid catalytic chlorination method, the reaction is carried out in a state where no water is present in the reaction system or a small amount of water is adsorbed on the powder particles. In such an anhydrous or slightly water system, the corrosiveness of chlorine and hydrogen chloride to the metal material is weak, and a relatively inexpensive nickel, stainless, or iron metal material can be used for the reactor. Furthermore, the powder particles brought into the post-processing step include:
Since only trace amounts of chlorine and hydrogen chloride remain,
Inexpensive metal materials can also be used in the post-processing step.

As described above, the gas-solid contact chlorination method of reacting a powder layer of a vinyl chloride resin with chlorine has excellent characteristics in terms of equipment cost, wastewater treatment, and safety.

However, according to the study of the present inventor, the chlorinated vinyl chloride resin obtained by the gas-solid contact chlorination method has a property that the molded product undergoes heat denaturation during hot molding or pressure molding, resulting in a dark brown color. A disadvantage was found in that it was colored. In the chlorinated vinyl chloride resin obtained by the water suspension chlorination method, the coloring of the molded product is slight, and the chlorinated vinyl chloride resin is used without problems in applications such as heat-resistant pipes which are the main use of the chlorinated vinyl chloride resin. . On the other hand, the coloring at the time of molding of the chlorinated vinyl chloride resin obtained by the gas-solid contact chlorination method was extremely thick and inferior.

[0013] With regard to chlorinated vinyl chloride resins of the water suspension chlorination method, which are less colored during molding, there are various methods for improving the color tone in order to respond to applications such as sheets and films requiring a high level of color tone. It has been devised. For example, in JP-A-03-166205, the color tone of the obtained chlorinated vinyl chloride resin is improved by post-chlorinating a vinyl chloride resin polymerized using hydroxypropylmethyl cellulose as a suspending agent by a water suspension chlorination method. A method has been proposed. Further, Japanese Patent Application Laid-Open Nos. Hei 5-186507 and Hei 5-
186520 discloses a method of post-chlorinating a vinyl chloride resin polymerized by using a cellulose suspending agent in combination with sodium alkyl sulfosuccinate or sodium alkyl diphenyl ether sulfonate. JP 63
JP-108004, JP-A-62-84103, JP-A-62-84103
Resin with low coloring properties by post-chlorinating a copolymer obtained by polymerizing vinyl chloride and olefins such as ethylene and propylene using a cellulosic suspending agent, such as -257914. Have also been proposed.
Further, JP-A-4-106110 discloses a method of post-chlorinating a vinyl chloride resin polymerized by using polyethylene oxide as a suspending agent.
No. 06108 describes a method of post-chlorinating a vinyl chloride resin polymerized using polyethylene oxide and cellulose ether as a suspending agent.

As described above, a method of post-chlorinating a vinyl chloride resin obtained by polymerizing a cellulose compound or polyethylene oxide as a dispersant without using partially saponified polyvinyl acetate is known in the art. It is. However, in these known techniques, the method of post-chlorination is not particularly limited, and only the post-chlorination reaction in the water-suspension chlorination method is described as an example. There is no example about the post-chlorination reaction in the gas-solid catalytic chlorination method, which is an important factor. Further, there is no description of extremely deteriorating the coloring property of a molded article of a chlorinated vinyl chloride resin obtained by a gas-solid contact chlorination method, and no solution is described. As described above, the extreme deterioration of the coloring property of the molded product in the gas-solid contact chlorination method,
Due to its mechanism, it is not found in the water suspension chlorination method. Therefore, the technique for improving the coloring of a molded article of a chlorinated vinyl chloride resin in the gas-solid contact chlorination method of the present invention is invented on a technical idea different from a conventionally known technique, and exhibits substantially different effects. Things.

[0015]

SUMMARY OF THE INVENTION The present inventors have found that the chlorinated vinyl chloride resin obtained by the gas-solid contact chlorination reaction has a higher coloring property of the molded product than the chlorinated vinyl chloride obtained by the water suspension chlorination method. It was found to be extremely poor, and was regarded as an important issue for practical use of the gas-solid catalytic chlorination method.

An object of the present invention is to provide a method for obtaining a chlorinated vinyl chloride resin having good coloring properties of a molded product in a gas-solid contact chlorination method excellent in post-treatment simplicity and facility cost. It is in.

[0017]

DISCLOSURE OF THE INVENTION The present inventors have studied the mechanism of coloring for the purpose of improving the colorability of a molded article of a chlorinated vinyl chloride resin obtained by a gas-solid contact chlorination method. . As a result, it was found that the coloring was caused by the acetic acid group of the partially saponified polyvinyl acetate, and that the coloring by the acetic acid group was specific to the chlorinated polyvinyl chloride resin obtained by the gas-solid contact chlorination method. Was.

As a result of intensive studies by the present inventors,
The amount of the partially saponified polyvinyl acetate used as a suspending agent is reduced to a certain amount or less and the polymerized vinyl chloride resin is post-chlorinated by gas-solid contact chlorination to synthesize a chlorinated vinyl chloride resin. As a result, a method for achieving both simplification of the post-treatment step and improvement of the coloring property of the molded product has been found, and the present invention has been completed.

That is, the first aspect of the present invention is as follows: (1) A partially saponified polyvinyl acetate having an addition amount in which the Y value represented by the formula (1) is in the range of 0 to 0.004, and Y = (1-α / 100) M (1) (where α is the saponification degree of the partially saponified polyvinyl acetate in mol%
Where M is the amount of the partially saponified polyvinyl acetate added to 100 parts by weight of the vinyl chloride monomer in terms of parts by weight) At least one kind of suspending agent other than the partially saponified polyvinyl acetate Using a suspending agent, in the presence of an oil-soluble polymerization initiator, a vinyl chloride resin is synthesized by suspension polymerization of a vinyl chloride monomer, and the obtained vinyl chloride resin and chlorine are vapor-solid. The present invention relates to a method for producing a chlorinated vinyl chloride resin, wherein a post-chlorination reaction is carried out in a contact field (claim 1).

(2) The method for producing a chlorinated vinyl chloride resin as described above, wherein the suspending agent other than the partially saponified polyvinyl acetate is a water-soluble cellulose ether and / or polyethylene oxide.

(3) The water-soluble cellulose ether is at least one selected from the group consisting of methylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, ethylcellulose and hydroxyethylmethylcellulose. (Claim 3).

(4) The method for producing a chlorinated vinyl chloride resin according to any one of the above (1) to (4), wherein the suspending agent does not contain partially saponified polyvinyl acetate. The present invention relates to the method for producing a chlorinated vinyl chloride resin according to any one of the above, wherein the amount of the water-soluble cellulose ether to be added is 0.0025 parts by weight or more and 0.20 parts by weight or less per part by weight (claim 5).

(6) The amount of polyethylene oxide to be added is 0.004 to 100 parts by weight of the vinyl chloride monomer.
The present invention relates to the method for producing a chlorinated vinyl chloride-based resin according to any one of the above, which is not less than 2.0 parts by weight and not more than 2.0 parts by weight.

(7) The method for producing a chlorinated vinyl chloride resin according to any one of the above, wherein light is used for accelerating the reaction of the chlorination reaction.

(8) The method for producing a chlorinated vinyl chloride resin as described above, wherein the light source for promoting the reaction is at least one selected from a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp. (Claim 8).

A second aspect of the present invention is (9) a dechlorination method characterized by subjecting the chlorinated vinyl chloride resin obtained by any of the above methods to a vacuum degassing treatment and / or a gas washing treatment. The present invention relates to a method for producing a hydrogenated chlorinated vinyl chloride resin (claim 9).

The third aspect of the present invention relates to (10) a chlorinated vinyl chloride resin obtained by the method described in any one of the above (claim 10).

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the mechanism of coloring of a molded article of chlorinated polyvinyl chloride containing partially saponified polyvinyl acetate and the reason that such coloring is a phenomenon peculiar to the gas-solid contact chlorination method will be described. I do.

[0029] The partially saponified polyvinyl acetate is obtained by modifying a part or most of acetic acid groups to hydroxyl groups by saponifying polyvinyl acetate, and is generally called a partially saponified product of polyvinyl alcohol. . The acetic acid group contained in the partially saponified polyvinyl acetate is a functional group that is more reactive than the hydroxyl group. Therefore, when the chlorinated vinyl chloride containing the acetic acid group is heated, the chlorinated vinyl chloride and the acetic acid group cause some reaction, and the main chain in the chlorinated vinyl chloride is cut or a double bond is generated. It is known that when a double bond is formed in a part of the main chain, a double bond is continuously formed in a vinyl chloride resin or a chlorinated vinyl chloride resin one after another (called a zipper reaction). Polymers with increased double bonds have a yellow to dark brown color. This is the coloring mechanism of the chlorinated vinyl chloride resin.

The cause of the above-mentioned coloring due to the acetic acid group specifically occurring in the chlorinated vinyl chloride resin obtained by the gas-solid catalytic chlorination method will be described. As described above, when chlorinating a vinyl chloride resin, a large amount of hydrogen chloride is generated according to the reaction formula shown in equation (2). When the vinyl chloride resin is post-chlorinated by the water suspension chlorination method, hydrogen chloride is dissolved in water, and the chlorinated vinyl chloride resin is suspended in high-concentration hydrochloric acid. The acetic acid groups in partially saponified polyvinyl acetate are known to be hydrolyzed (ie, saponified) in the presence of an acid catalyst and water. Therefore, in the reaction process of the water suspension chlorination method, the partially saponified polyvinyl acetate contained in the chlorinated polyvinyl chloride is modified into a completely saponified polyvinyl acetate, loses the acetic acid group, and deteriorates the coloring property of the molded product. It is no longer the causative substance. On the other hand, when synthesizing chlorinated vinyl chloride resin by gas-solid contact chlorination method, there is no water or only a very small amount of water is mixed in the system. The contained partially saponified polyvinyl acetate is not hydrolyzed. For this reason, acetic acid groups remain in the chlorinated vinyl chloride obtained by the gas-solid contact chlorination method, and the molded product is colored by the mechanism described in the preceding paragraph.

Next, a specific process for carrying out the present invention will be described. The present invention is a step of synthesizing a vinyl chloride resin by subjecting a vinyl chloride monomer to water suspension polymerization,
After the obtained vinyl chloride resin is dried, it is divided into a step of post-chlorination by a gas-solid contact chlorination method and a step of post-chlorination.

In the present invention, a vinyl chloride resin is synthesized by a suspension polymerization method. Generally, in the suspension polymerization method,
A method of adding a suspending agent and a polymerization initiator to a mixture of water and a vinyl chloride-based monomer and stirring the mixture is employed. The present inventors have found that the cause of the deterioration of the colorability of a molded article of a chlorinated vinyl chloride resin obtained by a gas-solid contact chlorination method is an acetate group remaining in partially saponified polyvinyl acetate used as a suspending agent. It has been found that it is necessary to reduce the amount of acetic acid groups used during the suspension polymerization reaction to a certain amount or less. Therefore, the present invention can be realized by defining a value corresponding to the ratio of the acetic acid group in the vinyl chloride monomer and the partially saponified polyvinyl acetate when performing the suspension polymerization, and limiting the range. .
That is, the addition amount of the partially saponified polyvinyl acetate when polymerizing the vinyl chloride resin is such that the Y value represented by the formula (1) is 0 to 0.
The amount is preferably in the range of 0.004, and most preferably the Y value is 0. That is, it is most preferable not to use partially saponified polyvinyl acetate or to use polyvinyl acetate in which acetic acid groups are completely saponified (completely saponified polyvinyl alcohol).

In the present invention, conventionally known suspending agents may be used as long as they do not contain an acetic acid group. For example, it is preferable to use water-soluble cellulose ether or polyethylene oxide alone or as a mixture. Specific examples of the water-soluble cellulose ether include methylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, ethylcellulose, and hydroxyethylmethylcellulose. Of these, hydroxypropyl methyl cellulose is preferably used. It is most preferable to use a mixture of a water-soluble cellulose ether and polyethylene oxide as the suspending agent, from the viewpoint that the suspension polymerization proceeds stably and the coloring property of the molded product is surely improved.

The amount of the water-soluble cellulose ether used as a suspending agent in the present invention is 0.0025 per 100 parts by weight of the vinyl chloride monomer from the viewpoint of polymerization stability.
The amount is preferably at least 0.2 part by weight, more preferably at most 0.20 part by weight so that the polymer particles do not become fine. From the same viewpoint, it is more preferably 0.01 to 0.05 part by weight.

The polyethylene oxide used as a suspending agent in the present invention preferably has an average molecular weight of 200,000 to 5,000,000. If the average molecular weight is less than 200,000, the polymerization stability may decrease, and if it is more than 5,000,000, the solubility when used tends to be poor. In addition, the amount of the vinyl chloride-based monomer 1 may be increased from the viewpoint of polymerization stability.
It is preferably 0.004 parts by weight or more with respect to 00 parts by weight, and is preferably 2.0 parts by weight or less from the viewpoint of solubility when used. For the same reason, 0.03 to 0.2 parts by weight is more preferably used. When a mixture of water-soluble cellulose ether and polyethylene oxide is used as a suspending agent, the total amount of the mixture is 0.0
It is preferably from 065 to 2.20 parts by weight, more preferably from 0.04 to 0.25 parts by weight.

The vinyl chloride monomer referred to in the present invention is a monomer comprising 0 to 20 parts by weight of another monomer copolymerizable with vinyl chloride alone or 100 to 80 parts by weight of vinyl chloride. Contains mixtures. Other monomers that can be copolymerized with vinyl chloride include olefins such as ethylene and propylene, allyl monomers such as allyl chloride and allyl glycidyl ether, and esters such as acrylates and methacrylates. And these can be used alone or in combination of two or more. However, vinyl acetate cannot be used because of the essence of the present invention that an acetate group is not contained.

As the oil-soluble polymerization initiator used in the present invention, conventionally known initiators can be used. For example, benzoylperoxide, laurylperoxide, di-2-ethylhexylperoxydicabonate, t-butylperoxyneodecanate, 3,5,5-trimethylhexanoylperoxydicabonate, S- Organic peroxides such as butyl peroxydica-bonate and diisopropyl peroxydica-carbonate, azo compounds such as azobisisobutyrovaleronitrile and azobisvaleronitrile can be used, and these initiators can be used alone. Alternatively, two or more kinds may be used in combination. Further, the amount of use is about 0.001 to 2 parts by weight based on 100 parts by weight of the vinyl chloride monomer,
It is preferable from the viewpoint of polymerization stability in suspension polymerization of a vinyl chloride resin.

In the present invention, conventionally known polymerization additives such as a chain transfer agent, a coloring improver for a molded product, a metal salt and other additives may be used according to the purpose.

Examples of the chain transfer agent include mercapto compounds such as 2-mercaptoethanol, butylmercaptan, octylmercaptan, dodecyl-N-mercaptan, halogenated olefins such as trichloroethylene, and olefins such as 1-butene. May be used alone or in combination of two or more.

Examples of the coloring improver for molded products include sulfur-containing compounds such as distearyl dithiopropionate and dilauryl dithiopropionate, and t-butylhydroxyanisole and di-t-butylhydroxytoluene. Such as phenolic compound antioxidants, sorbitan ester compounds and glycerin ester compounds,
These may be used alone or in combination of two or more.

The metal salts include alkali metal, alkaline earth metal, metalloid sulfate, hydrochloride and borate, and these may be used alone or in combination of two or more.

In the step of post-chlorination of the vinyl chloride resin obtained by the above method by a gas-solid catalytic chlorination method, a suspension of the vinyl chloride resin is prepared by a suspension polymerization method, and the suspension is dehydrated.・
Dry to obtain a powdery vinyl chloride resin. Further, the target chlorinated vinyl chloride resin is synthesized by reacting the obtained powdery vinyl chloride resin with chlorine.

In the chlorination reaction, the vinyl chloride resin used in the present invention is preferably a flowable powder from the viewpoint of easy handling and uniform progress of the reaction. The powder as referred to in the present invention is an aggregate of particles that can move alone in a gas phase, and the size of each particle is approximately 10 μm or more and 2000 μm or less (average particle size is 50 to 500 μm). In range. The particle size distribution of the powder particles is preferably uniform from the viewpoint of enhancing the fluidity of the powder and allowing the reaction to proceed uniformly, and the absolute value of the particle size has a preferable range. Therefore, the powder layer of the vinyl chloride resin used in the present invention has a thickness of 50%.
It is preferably an aggregate of powder particles (average particle diameter of 100 to 300 μm) mainly having a particle diameter of not less than μm and not more than 500 μm. Each powder particle may be composed of a continuous phase of a vinyl chloride resin, or may be an aggregate of smaller primary particles.

In the present invention, if the powder layer is a powder layer in which the vinyl chloride resin can flow, it can be used even if it contains moisture. However, if the water content is too large, water and hydrogen chloride become azeotropic, It becomes difficult to remove the generated hydrogen chloride from the resin. Therefore, the water content in the powder layer is preferably less than 5% by weight. Further, in order to prevent aggregation of the powder particles due to static electricity and to prevent the powder particles from adhering to the container, the vinyl chloride resin powder may intentionally contain less than 5% by weight of water.

When a vinyl chloride resin is synthesized by a suspension polymerization method, fine particles of the vinyl chloride resin are dispersed in water, so that powder particles can be obtained only by drying. However, in this case, a continuous layer called a skin layer is formed on the surface of the powder particles, which impedes the penetration of chlorine gas into the inside, and reduces the reaction rate or the reaction rate in the radial direction of the powder particles. It may be uneven. Therefore, it is also effective that the powder particles of the vinyl chloride resin used in the present invention are pulverized in advance before the post-chlorination reaction to break the skin layer before use.

The essence of the present invention is to obtain a chlorinated sensitized vinyl resin by post-chlorinating a vinyl chloride resin having an acetic acid group content of a certain amount or less. Therefore, if the partially saponified polyvinyl acetate is not contained, it can be applied to a vinyl chloride resin synthesized by a bulk polymerization method other than the suspension polymerization method, a gas phase polymerization method, or an emulsion polymerization method. For example, the same effect as in the present invention can be obtained by pulverizing a vinyl chloride resin obtained by a bulk polymerization method or a gas phase polymerization method into a powder having the above-mentioned particle diameter range and then chlorinating the same. In addition, the vinyl chloride resin obtained by the emulsion polymerization method can be chlorinated after granulation into a powder having the above-mentioned particle size range before and after drying, for example, by using a spray dryer. is there.

The chlorine used in the present invention can be used without particular limitation as long as it is generally used industrially. However, if oxygen is contained in chlorine, the thermal stability of the obtained chlorinated vinyl chloride resin and the coloring property of the molded product are deteriorated. Therefore, the concentration of oxygen contained in chlorine is 100 p.
pm or less, and most preferably 20 ppm or less. In addition, if water is contained in chlorine, hydrogen chloride generated by the reaction becomes difficult to remove from the resin, or may cause corrosion of the device,
It is preferably at most 1000 ppm. Further, chlorine may be diluted with an inert gas such as nitrogen or argon in order to adjust the reaction rate or the reaction temperature.

The method for supplying chlorine in the present invention will be described. In the present invention, the state of chlorine supplied into the reactor for the post-chlorination reaction may be gas or liquid. Generally, chlorine used industrially is liquid chlorine sealed in a cylinder. Therefore, in the case of supplying gaseous gas, the liquid chlorine removed from the liquid chlorine cylinder may be vaporized in another container and then supplied to the reaction container. When supplying liquid chlorine into the reaction vessel, the liquid chlorine removed from the liquid chlorine cylinder may be vaporized in the reactor. The method of vaporizing chlorine in the reactor is preferable because it has the effect of heat of vaporization depriving the heat of reaction and mitigating a rise in temperature in the reactor. However, if liquid chlorine comes into direct contact with the vinyl chloride resin, the surface structure and internal structure of the vinyl chloride resin will change, so the liquid chlorine will not come into contact with the vinyl chloride resin before vaporizing in the reaction vessel. It needs to be devised.

In the method of post-chlorination of the vinyl chloride resin in the present invention, a conventionally known method can be used without limitation as long as the gas-solid contact reaction between the vinyl chloride resin and chlorine gas is utilized. . The most suitable method for the gas-solid contact reaction is a method in which a powdery solid (that is, a vinyl chloride resin) in a fluid state and a gas (that is, a chlorine gas) are mixed and reacted. The flowing state refers to all states in which the powder particles are moving or moving continuously or intermittently and continuously. As an example, there is a method using a fluidized bed in which a gas flows through a powder bed to move particles.
In order to bring the powder into a fluid state in the present invention, a method in a conventionally used powder reactor may be used,
Mixing equipment, stirring equipment, combustion equipment, drying equipment, crushing equipment,
A method used for a granulating device or the like may be applied. Specifically, a container rotating type device such as a horizontal cylindrical type, a V type, a double cone type, a swing rotary type, a single-shaft ribbon type, a double-shaft paddle type, a rotary plow type, a twin-shaft planetary stirring type, It is preferable to use a mechanical stirring type device such as a conical screw type. The specific shapes of these devices are described in Chemical Engineering Handbook (edited by the Society of Chemical Engineers, 6th revised edition, p. 876). Among these devices, for example, a container rotating type reactor as shown in FIG.
This is more effective for the present invention than a mechanical stirring type device or a fluidized bed type device in that all the powder particles can be surely fluidized and can be uniformly exposed on the surface of the powder layer.

In a normal state, the reaction rate between the vinyl chloride resin and the chlorine gas is extremely slow. Therefore, it is necessary to mix the powdery vinyl chloride resin with the chlorine gas and to take measures for accelerating the reaction. As a method of accelerating the reaction, a method of irradiating light, a method of adding a catalyst, a method of applying heat, and the like can be used, and these can be used in combination. In particular, the method of irradiating light is suitable for the present invention because it has a high reaction promoting effect and can obtain chlorinated vinyl chloride having a high reaction rate.

The types of the light source used in the present invention will be described. The role of light in the present invention is to excite chlorine to generate chlorine radicals and promote the chlorine addition reaction to the vinyl chloride resin. Since chlorine has an energy absorption band in a wide wavelength range from the visible region to ultraviolet light, various light sources such as sunlight and artificial light can be used in the present invention. Since chlorine has the strongest absorption band for ultraviolet light having a wavelength of 320 to 360 nm, it is preferable to use a light source containing a large amount of this wavelength range. Specifically, a light source that emits a large amount of ultraviolet light, such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp, may be used. The light source can be covered with a transparent cover according to purposes such as protection of the light source and cooling. In this case, the material of the transparent cover is quartz,
Pyrex (registered trademark), hard glass, soft glass tube and the like can be used, but in order to effectively use the wavelength in the ultraviolet region effective for the chlorination reaction, it is preferable to use quartz or Pyrex, Most preferably, quartz is used.

The inside and the surface of the particles of the chlorinated vinyl chloride resin obtained by the gas-solid contact chlorination method of the present invention contain unreacted chlorine and hydrogen chloride as a reaction product. In order to industrially use the obtained chlorinated vinyl chloride as a product, it is necessary to remove chlorine and hydrogen chloride. As a method for removing chlorine or hydrogen chloride, a chlorinated vinyl chloride resin after the post-chlorination reaction is stirred or a fluidized bed is formed in a vessel in which a gas such as nitrogen, air, argon, or carbon dioxide is circulated. Examples of the method include a gas washing method and a vacuum degassing method in which a container containing a chlorinated vinyl chloride resin after a post-chlorination reaction is vacuum degassed to remove chlorine and hydrogen chloride. In order to enhance the effect of dehydrochlorination, horizontal cylinder type, V type,
Container rotation type devices such as double cone type and swing rotation type, single axis ribbon type, double axis paddle type, rotating plow type, twin axis planetary stirring type,
Use a mechanical stirring type device such as a conical screw type, etc.
It is advisable to circulate gas in the reaction vessel or to degas in a vacuum. The specific shapes of these devices are described in Chemical Engineering Handbook (edited by the Society of Chemical Engineers, 6th revised edition, p. 876). In addition, in order to omit the equipment for the dehydrochlorination step and to reduce equipment costs, after the end of the gas-solid catalytic chlorination reaction,
With the chlorinated vinyl chloride resin in the reactor, a cleaning gas can be passed or vacuum degassing can be performed.

[0053]

EXAMPLES Next, the method of the present invention will be specifically described with reference to examples. However, the present embodiment does not limit the present invention.

Example 1 In a stainless steel autoclave equipped with a stirring blade, 400 parts of ion-exchanged water, 0.005 part by weight of polyethylene oxide having an average molecular weight of 2,000,000, and 0.04 part by weight of hydroxypropyl methylcellulose were used. Parts, 70 parts by weight of di-2-ethylhexylperoxydica carbonate in 0.05 parts by weight of isoparaffin solution, and the autoclave was degassed under vacuum, and then 100 parts by weight of vinyl chloride monomer. The department was charged. The Y value at this time is 0
It is. Thereafter, suspension polymerization was performed with stirring to obtain a vinyl chloride resin having a polymerization degree of about 1,000. The suspension of the vinyl chloride resin was dehydrated and dried to obtain a powdery vinyl chloride resin containing no partially saponified polyvinyl acetate. This was designated as vinyl chloride resin A.

Using the apparatus shown in FIG. 1, post-chlorination of vinyl chloride resin A was carried out by a gas-solid reaction. 187.50 g of powder of vinyl chloride resin A in a reaction vessel (pyrex eggplant-shaped flask having a capacity of 1000 ml) = 3
mol. While the reaction vessel was immersed in a warm bath at 30 ° C. and rotated, nitrogen gas was passed through the space portion of the reaction vessel at a flow rate of 200 ml / min for 60 minutes, and chlorine gas was further passed at a flow rate of 200 ml / min for 30 minutes. Thereafter, the flow rate of chlorine gas was increased to 600 ml / min, and the surface of the powder layer was irradiated with ultraviolet rays using a 400 W high-pressure mercury lamp installed at a position 35 cm away from the upper surface of the powder layer. The reaction starts when the mercury lamp is turned on, and a mixed gas of chlorine and hydrogen chloride is discharged from the gas outlet. The generated hydrogen chloride was absorbed in water, and the hydrogen chloride generation amount and the chlorine content of the chlorinated vinyl chloride resin were continuously calculated from the neutralization titration value of the hydrochloric acid. When a thermocouple was inserted into the powder layer and the temperature of the powder layer was measured, the reaction started after the mercury lamp was turned on and the reaction heat was generated. Reached. Since the reaction rate decreases as the reaction proceeds, when the chlorine content reaches 61.4% by weight, the temperature of the hot bath is reduced to 45%.
° C, and when the chlorine content reached 64.3% by weight, the temperature of the hot bath was raised to 60 ° C. The mercury lamp was turned off when the reaction time had elapsed 180 minutes, and the reaction was terminated.

After the completion of the reaction, while keeping the temperature of the reaction vessel at 60 ° C., nitrogen gas was passed through the reaction vessel at a flow rate of 600 ml / min to remove residual chlorine and hydrogen chloride by washing. Sample 1 after continuous nitrogen replacement for 100 minutes
And (Example 2) Post-chlorination using the same reactor as in Example 1 and the same vinyl chloride resin A (powder-like chlorinated vinyl chloride resin containing no partially saponified polyvinyl acetate) as in Example 1 The reaction was performed. In a reaction vessel (pyrex eggplant-shaped flask with a capacity of 1000 ml), place vinyl chloride resin A
187.52 g = 3 mol. 6 reaction vessels
While immersed in a warm bath at 0 ° C. and rotated, nitrogen gas was passed through the space portion of the reaction vessel at a flow rate of 200 ml / min for 60 minutes, and chlorine gas was passed at a flow rate of 200 ml / min for 30 minutes. Thereafter, the chlorine gas was increased to 600 ml / min, and 40 was set at a position 35 cm away from the upper surface of the powder layer.
The surface of the powder layer was irradiated with ultraviolet rays using a 0 W high-pressure mercury lamp. The reaction starts when the mercury lamp is turned on, and a mixed gas of chlorine and hydrogen chloride is discharged from the gas outlet. Also,
When a thermocouple was inserted into the powder layer and the temperature of the powder layer was measured, the reaction started after the mercury lamp was turned on and the reaction heat was generated. Reached. Since the reaction rate decreases as the reaction proceeds, the temperature of the warm bath was gradually increased and controlled so that the temperature of the powder layer became constant at around 80 ° C. The reaction was carried out for 150 minutes from the start of the reaction, and the mercury lamp was turned off to terminate the reaction.

After the completion of the reaction, while maintaining the temperature of the reaction vessel at 60 ° C., nitrogen gas was passed through the reaction vessel at a flow rate of 600 ml / min to wash and remove residual chlorine and hydrogen chloride. Sample 2 after nitrogen replacement for 100 minutes
And Example 3 Using the same reactor as in Examples 1 and 2, the same vinyl chloride resin A (powder-like chlorination containing no partially saponified polyvinyl acetate) as used in Examples 1 and 2 was used. A post-chlorination reaction was performed. 187.82 g of vinyl chloride resin A in a reaction vessel (pyrex eggplant-shaped flask having a capacity of 1000 ml)
= 3 mol. While the reaction vessel was immersed in a 60 ° C. hot bath and rotated, 200 ml /
Flow nitrogen gas for 60 minutes at a flow rate of
/ Min flow of chlorine gas for 30 minutes. Then, the chlorine gas was increased to 600 ml / min, and 3
The surface of the powder layer was irradiated with ultraviolet rays using a 400 W high-pressure mercury lamp installed at a position separated by 5 cm. The reaction starts when the mercury lamp is turned on, and a mixed gas of chlorine and hydrogen chloride is discharged from the gas outlet. When a thermocouple was inserted into the powder layer and the temperature of the powder layer was measured, the reaction started after the mercury lamp was turned on and reaction heat was generated. 81 ° C was reached. Since the reaction rate decreases as the reaction proceeds, the temperature of the warm bath was gradually increased and controlled so that the temperature of the powder layer became constant at around 80 ° C. The reaction was carried out for 155 minutes from the start of the reaction, and the mercury lamp was turned off to terminate the reaction.

After the completion of the reaction, while keeping the temperature of the reaction vessel at 60 ° C., the reaction vessel was evacuated with an aspirator for 100 minutes to remove residual hydrogen chloride and chlorine. Example 4 400 parts of ion-exchanged water, 0.09 parts by weight of polyethylene oxide having an average molecular weight of 2,000,000, and a saponification degree of 8 were placed in a stainless steel autoclave equipped with a stirring blade.
0.02 parts by weight of 0% partially saponified polyvinyl acetate and 0.05 parts by weight of a 70% concentration of isoparaffin solution of di-2-ethylhexylperoxydicacarbonate were charged, and the inside of the autoclave was evacuated. After degassing, 100 parts by weight of a vinyl chloride monomer was charged. At this time, the Y value of the fourth embodiment is 0.004. After that, suspension polymerization is performed under stirring,
A vinyl chloride resin having a degree of polymerization of about 1000 was obtained. The suspension of the vinyl chloride resin was dehydrated and dried to obtain a powdery vinyl chloride resin B.

Using the same reactor as in Examples 1 to 3, a post-chlorination reaction was carried out on the vinyl chloride resin B. 187.87 g of powder of vinyl chloride resin C was placed in a reaction vessel (a Pyrex eggplant-shaped flask having a capacity of 1000 ml) = 3.
mol. While the reaction vessel was immersed in a warm bath at 30 ° C. and rotated, nitrogen gas was passed through the space portion of the reaction vessel at a flow rate of 200 ml / min for 60 minutes, and chlorine gas was further passed at a flow rate of 200 ml / min for 30 minutes. Thereafter, the chlorine gas was increased to 600 ml / min, and 35 c
The surface of the powder layer was irradiated with ultraviolet rays using a 400 W high-pressure mercury lamp installed at a distance of m. The reaction starts when the mercury lamp is turned on, and a mixed gas of chlorine and hydrogen chloride is discharged from the gas outlet. When a thermocouple was inserted into the powder layer and the temperature of the powder layer was measured, the reaction started after the mercury lamp was turned on and reaction heat was generated. 53 ° C. was reached. Since the reaction rate decreases as the reaction proceeds, when the chlorine content reaches 61.4% by weight, the temperature of the hot bath is set to 45 ° C., and the chlorine content is 64.3%.
When the weight percent was reached, the temperature of the hot bath was raised to 60 ° C.
When the reaction time passed 175 minutes, the mercury lamp was turned off and the reaction was terminated.

After the completion of the reaction, while maintaining the temperature of the reaction vessel at 60 ° C., nitrogen gas was passed through the reaction vessel at a flow rate of 600 ml / min to wash and remove residual chlorine and hydrogen chloride. Sample 4 after continuous nitrogen replacement for 100 minutes
And (Comparative Example 1) In a stainless steel autoclave equipped with a stirring blade, 400 parts of ion-exchanged water, 0.005 parts by weight of polyethylene oxide having an average molecular weight of 2,000,000, and a partially saponified polyvinyl acetate having a saponification degree of 80%. And 0.05 parts by weight of an isoparaffin solution of di-2-ethylhexyl par-oxydica-bonate having a concentration of 70% was charged.
After the interior of the autoclave was degassed under vacuum, 100 parts by weight of a vinyl chloride monomer was charged. At this time, the Y value in Comparative Example 1 is 0.01. After that, suspension polymerization is performed under stirring,
A vinyl chloride resin having a degree of polymerization of about 1000 was obtained. The suspension of the vinyl chloride resin was dehydrated and dried to obtain a powdery vinyl chloride resin C containing partially saponified polyvinyl acetate.

Using the same reactor as in Examples 1 to 4, a post-chlorination reaction was carried out on the vinyl chloride resin C. 187.87 g of vinyl chloride resin B = 3 mol in a reaction vessel (pyrex eggplant-shaped flask having a capacity of 1000 ml)
Was charged. While the reaction vessel was immersed in a warm bath at 30 ° C. and rotated, nitrogen gas was passed through the space portion of the reaction vessel at a flow rate of 200 ml / min for 60 minutes, and chlorine gas was further passed at a flow rate of 200 ml / min for 30 minutes. Then, add chlorine gas
The pressure was increased to 00 ml / min, and the surface of the powder layer was irradiated with ultraviolet rays using a 400 W high-pressure mercury lamp installed at a position 35 cm away from the upper surface of the powder layer. The reaction starts when the mercury lamp is turned on, and a mixed gas of chlorine and hydrogen chloride is discharged from the gas outlet. When a thermocouple was inserted into the powder layer and the temperature of the powder layer was measured, the reaction started after the mercury lamp was turned on and reaction heat was generated. 53 ° C. was reached. When the chlorine content reaches 61.4% by weight, the temperature of the warm bath is set to 45 ° C., and when the chlorine content reaches 64.3% by weight, the temperature of the hot bath is reduced to 60%. ° C. The mercury lamp was turned off when the reaction time had elapsed 180 minutes, and the reaction was terminated.

After the completion of the reaction, while keeping the temperature of the reaction vessel at 60 ° C., nitrogen gas was passed through the reaction vessel at a flow rate of 600 ml / min to remove residual chlorine and hydrogen chloride by washing. A sample which was continuously purged with nitrogen for 100 minutes was designated as Comparative Sample 1.

The final chlorine content of Samples 1 to 4 and Comparative Sample 1 was calculated from the weight change before and after the reaction. That is, the chlorine content of the vinyl chloride resin was set to 56.8% by weight, and the change in weight of the powder resin before and after the reaction was calculated on the assumption that hydrogen in the vinyl chloride resin was replaced by chlorine. The final chlorine content of Comparative Samples 2 and 3 is
Calculated by neutralizing titration of the suspension after the reaction. That is, the calculation was performed on the assumption that the total hydrochloric acid calculated from the neutralization titration value was generated by the chlorination reaction of the vinyl chloride resin represented by the formula (2).

The method for evaluating the coloring property of the molded product of each sample is described below. For 100 parts by weight of sample, M
10 parts by weight of BS (B31 manufactured by Kanegafuchi Chemical Industry Co., Ltd.), 2 parts by weight of a tin-based stabilizer, and 1.7 parts by weight of a lubricant were blended and kneaded at 195 ° C. for 3 minutes with an 8-inch roll. The obtained sheet was pressed at 200 ° C. for 10 minutes to obtain a test piece. The color of the surface of the obtained test piece was measured with a colorimeter (Minolta, C
R-200) was used to measure the L value, and the coloring of the molded product was evaluated. The L value is a value indicating the ratio of the reflected light from the test piece to the incident light. The larger the L value, the lighter the color of the test piece, and the smaller the L value, the deeper the color of the test piece. However, since the color of the test piece may change due to a slight difference in processing temperature or processing thickness, the L value of the test piece of the comparative sample 3 obtained by simultaneously pressing each sample in the same press machine is L = L ₀ . And standardized. That is, the coloring property of the molded product was evaluated by the K value shown in the formula (3). The larger the K value, the less coloring of the molded product and the better the coloring property of the molded product.

K = L / L ₀ (3) The amount of residual hydrogen chloride in each sample was calculated by a neutralization titration method. After precisely weighing each sample, the sample was dissolved in tetrahydrafuran and extracted with a mixture of methanol and water, and the amount of hydrochloric acid in the extract was neutralized and titrated. The amount of hydrochloric acid contained in the sample was calculated from the difference between the neutralization titration value of each sample and the neutralization titration value of the mixture alone.

Table 1 shows the results of Examples 1 to 4 and Comparative Example 1 at the same time. From the results in Table 1, all of the chlorinated vinyl chloride resins of Examples 1 to 4 obtained by post-chlorination of a vinyl chloride resin having a Y value of 0.004 or less by a gas-solid contact chlorination method. It shows a high K value. On the other hand, the chlorinated vinyl chloride resin of Comparative Example 1 obtained by post-chlorination of a vinyl chloride resin having a Y value of 0.004 or more by a gas-solid contact chlorination method has a low K value, It turns out that coloring at the time of molding is intense. Table 1 shows the experimental results of Examples 1 to 4 and Comparative Example 1.

[0067]

[Table 1]

[0068]

According to the present invention, a mixture of at least one kind of suspending agent selected from non-partially saponified polyvinyl acetate and non-partially saponified polyvinyl acetate having a specific amount or less is used as a suspending agent, and the presence of an oil-soluble polymerization initiator is determined. Hydrochloride can be easily removed by performing a post-chlorination reaction in a gas-solid contact field between a vinyl chloride resin obtained by suspension polymerization of a vinyl chloride monomer and chlorine in a gas-solid contact field, and coloring of the molded product is reduced. Low chlorinated vinyl chloride resin can be produced.

[Brief description of the drawings]

FIG. 1 is an apparatus diagram used in an example of a gas-solid catalytic chlorination reaction.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4J011 JA06 JA07 JA10 JB22 JB26 JB27 4J100 AA02Q AA03Q AC02Q AC03P AE18Q AL02Q BC54Q CA01 CA03 CA31 EA05 FA08 FA21 FA39 HA21 HB04 HE01 HE20 HE22

Claims (10)

[Claims] The Y value represented by the formula (1) is 0 to 0.00.
4, and Y = (1-α / 100) M (1) (where α represents the degree of saponification of the partially saponified polyvinyl acetate in mol%
Where M is the amount of the partially saponified polyvinyl acetate added to 100 parts by weight of the vinyl chloride monomer in terms of parts by weight) At least one kind of suspending agent other than the partially saponified polyvinyl acetate Using a suspending agent, a vinyl chloride resin is synthesized by suspension polymerization of a vinyl chloride monomer in the presence of an oil-soluble polymerization initiator, and the obtained vinyl chloride resin and chlorine are gas-solid. A method for producing a chlorinated vinyl chloride resin, wherein a post-chlorination reaction is performed in a contact field. 2. The method according to claim 1, wherein the suspending agent other than the partially saponified polyvinyl acetate is a water-soluble cellulose ether and / or polyethylene oxide. 3. The water-soluble cellulose ether is at least one selected from methylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, ethylcellulose, and hydroxyethylmethylcellulose. 3. The method for producing a chlorinated vinyl chloride resin according to any one of Items 1 to 2. 4. The method according to claim 1, wherein the suspending agent does not contain partially saponified polyvinyl acetate. 5. The addition amount of the water-soluble cellulose ether to 100 parts by weight of the vinyl chloride monomer is 0.0025.
The method for producing a chlorinated vinyl chloride resin according to any one of claims 1 to 4, which is not less than 0.20 parts by weight and not more than 0.2 parts by weight. 6. The chlorinated vinyl chloride-based composition according to claim 1, wherein the amount of the polyethylene oxide is 0.004 to 2.0 parts by weight based on 100 parts by weight of the vinyl chloride-based monomer. Method of manufacturing resin. 7. The method for producing a chlorinated vinyl chloride resin according to claim 1, wherein light is used for accelerating the chlorination reaction. 8. The method for producing a chlorinated vinyl chloride resin according to claim 7, wherein the light source for promoting the reaction is at least one selected from a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp. . 9. A dechlorination-treated chlorinated chlorinated resin obtained by subjecting the chlorinated vinyl chloride-based resin obtained by the method according to claim 1 to vacuum degassing treatment and / or airflow washing treatment. A method for producing a vinyl chloride resin. 10. A chlorinated vinyl chloride resin obtained by the method according to claim 1.