JPH0472848B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a graft polymerization method, and more specifically, the present invention relates to a graft polymerization method, and more particularly, the present invention relates to a graft polymerization method in which vinyl chloride monomer or
The present invention relates to a novel graft polymerization method for polymerizing a mixture of a vinyl chloride monomer and a copolymerizable monomer. Graft polymerization of vinyl chloride monomer or a mixture of vinyl chloride monomer and a monomer copolymerizable with vinyl chloride monomer (hereinafter abbreviated as vinyl chloride monomer etc.) to the backbone polymer. Methods for producing vinyl chloride-based graft copolymers are already well known. Such graft copolymers are usually produced by a so-called suspension polymerization method, in which a backbone polymer is welded to a vinyl chloride monomer or the like, and then suspended in an aqueous medium and polymerized. In recent years, a graft polymerization method has been proposed in which properties such as transparency are improved by polymerizing the trunk polymer in a swollen state without dissolving it. However, as a result of studies conducted by the present inventors, in this production method, when components such as vinyl chloride monomers polymerize and become contained in the copolymer at about 70%, the polymerization rate decreases dramatically, resulting in industrial production. It was found that it was extremely difficult to react further than that. Additionally, if excessive amounts of monomer and initiator are added, a large amount of graft copolymers with different contents of components such as vinyl chloride monomer and homopolymer powder of vinyl chloride monomer will be produced as by-products. It has been found that separation of these mixtures is extremely difficult industrially. The present invention is aimed at solving these drawbacks, and aims to solve the problems by using vinyl chloride monomer,
In the presence of 10 to 200 parts by weight of a backbone polymer such as water, a suspension stabilizer, an oil-soluble initiator, and a vinyl chloride monomer per 100 parts by weight, vinyl chloride monomer is polymerized at saturated steam pressure to produce vinyl chloride monomer. 40 to 70 components such as mass
A vinyl chloride graft copolymer [A] containing % by weight is produced, and then vinyl chloride monomer, etc. is added in the presence of the graft copolymer [A] at a polymerization pressure lower than the saturated vapor pressure of the vinyl chloride monomer. The object of the present invention is to provide a novel graft polymerization method for obtaining a vinyl chloride graft copolymer [B] containing 50 to 95% by weight of components such as vinyl chloride monomers, by carrying out suspension polymerization while maintaining the temperature. The present invention will be explained in further detail below. The backbone polymer used in the present invention includes polyethylene, amorphous polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene-
Polyolefin polymers such as vinyl acetate copolymer, ethylene-propylene-diene copolymer, chloroprene rubber, butyl rubber, styrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer Rubbers such as isoprene rubber, nitrile rubber, or rubber-containing copolymers,
Examples include condensation polymers such as polyester and polyurethane. The trunk polymer is preferably present in an amount of 10 to 200 parts by weight per 100 parts by weight of vinyl chloride monomer. Examples of monomers that can be copolymerized with vinyl chloride monomers include olefins such as ethylene and propylene, and vinyl esters of monocarboxylic acids having a carbon number ranging from 1 to 18, such as vinyl acetate and vinyl laurate. , methyl acrylate, butyl acrylate,
The number of carbon atoms in the alkyl group of methyl methacrylate, butyl methacrylate, octyl methacrylate, etc. is 1 or more
Examples include acrylic acid alkyl esters and methacrylic acid alkyl esters within the range of 18, alkyl vinyl ethers such as butyl vinyl ether and lauryl vinyl ether, and vinylitene chloride. These monomers can be used freely, either singly or in combination, but the amount to be mixed is preferably 50 parts by weight or less per 100 parts by weight of vinyl chloride. The suspension stabilizer may be one commonly used in suspension polymerization such as vinyl chloride monomer, such as partially saponified polyvinyl acetate, gelatin, alkyl cellulose, fatty acid ester of polyethylene glycol, etc. . As the oil-soluble radical polymerization initiator, azo compounds and peroxides can be used, such as azobisisobutyronitrile, dialkyl peroxydicarbonate, lauroyl peroxide, and the like. The pressure below the saturated steam pressure is 30 to 90% of the saturated steam pressure at the reaction temperature of vinyl chloride monomer.
% pressure range applies. If it is 90% or more, the effect of polymerization below the saturated steam pressure will not be exhibited, and if it is less than 30%, the reaction rate will be too slow, which is not preferable. An example of a method for keeping the pressure constant is a method in which vinyl chloride monomer or the like is added continuously or intermittently to the polymerization vessel. The polymerization temperature is in the range of 30 to 80°C, as in the case of ordinary vinyl chloride monomer polymerization. The amount of components such as vinyl chloride monomer in the graft copolymer [A] is preferably 40 to 70% by weight. If it is less than 40%, components such as vinyl chloride monomer will be removed by 70% during the subsequent polymerization below the saturated vapor pressure.
If it exceeds 70%, the polymerization rate becomes extremely slow, and if it exceeds 70%, the effects of polymerization below the saturated vapor pressure, such as good transparency, cannot be obtained. During the graft polymerization according to the present invention, polymerization regulators such as dodecyl mercaptan may be added if necessary, and processing stabilizers and auxiliaries for vinyl chloride polymers, such as epoxy stabilizers, metal soaps, etc., may be added in advance. can also be added. As described above, the vinyl chloride graft copolymer [B] obtained by the method of the present invention has good transparency and can be used in a wide range of applications in the future. The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. In addition, measurements of properties in the following examples were performed in accordance with the following. [A] Combination

[Table] [B] Transparency The formulation in Table 1 was kneaded using a 6-inch roll for 5 minutes at a roll temperature of 160°C, then kneaded at 180°C for 15 minutes,
It was pressed at 100 kg/cm ³ to form a 1 mm thick sheet, and its light transmittance and haze were measured using a haze meter. [C] Backbone polymer Ethylene-vinyl acetate copolymer (EVA in the table)
) is Ultrasen manufactured by Toyo Soda Kogyo Co., Ltd.
750, ethylene-ethyl acrylate copolymer (denoted as EEA in the table) is manufactured by Nippon Unicar Co., Ltd.
DPDJ9169, polymethyl methacrylate (in the table
PMMA) is Terpet 60N manufactured by Asahi Kasei Industries, Ltd. Polyurethane (denoted as PU in the table) is
Paraprene 22S manufactured by Nippon Polyurethane Co., Ltd., ethylene-propylene-diene copolymer (in the table)
EPDM) is EP57C manufactured by Japan Synthetic Rubber Co., Ltd.
Chlorinated polyethylene (denoted as CPE in the table) is
Daiso Raku G235 manufactured by Osaka Soda Co., Ltd. was used in each case. Examples 1 to 5 After charging 27 kg of pure water, 4.6 kg of trunk polymer, and 36 g of partially saponified polyvinyl acetate into a polymerization container made of 50 stainless steel equipped with a stirring device, the lid was closed, the air was replaced with nitrogen, and the vacuum was applied to dissolve vinyl chloride. 12.6Kg of monomer was introduced. Heating was started while stirring, and stirring was continued at 60° C. for 6 hours. Subsequently, 2,2′azobis2,4
-8 g of dimethylvaleronitrile was added to initiate polymerization. After 4 hours, the unreacted vinyl chloride monomer was recovered and the pressure was brought to 70% of the saturated steam pressure. After that, vinyl chloride monomer was added successively to maintain this pressure, and after polymerization for 6 hours, it was dehydrated. It was dried to obtain a graft copolymer [B]. Table 2 shows the measurement results of the properties of the obtained graft copolymer [B]. Examples 6 to 7 After charging 27 kg of pure water, 8 kg of trunk polymer, and 50 g of partially saponified polyvinyl acetate into the polymerization container used in Example 1, the lid was closed, the atmosphere was replaced with nitrogen, and the vinyl chloride monomer was dissolved in a vacuum. Heating was started with stirring, and stirring was continued at 65°C for 2 hours. followed by 2,2'azobis2,4-dimethylvaleronitrile
Polymerization was started by adding 7.7 g. After 5 hours, unreacted vinyl chloride monomer was recovered and the saturated vapor pressure was reduced to 60%.
%, vinyl chloride monomer was successively added so as to maintain this pressure, and after polymerization for 4 hours, dehydration and drying were performed to obtain a graft copolymer [B]. Table 2 shows the measurement results of the properties of the obtained graft copolymer [B]. Comparative Examples 1 to 2 27 kg of pure water, 1.1 kg of backbone polymer, 16 kg of vinyl chloride monomer, and 40 kg of partially saponified polyvinyl alcohol were charged into the polymerization container used in Example 1, and dissolved at 60°C for 3 hours. , 2'azobis2,4-dimethylvaleronitrile (6 g) was added, and the mixture was reacted for about 8 hours. Thereafter, it was dehydrated and dried to obtain a graft copolymer. The results are shown in Table-2. Comparative Example 3 In the polymerization container used in Example 1, 30 kg of pure water, 5 kg of chlorinated polyethylene, and partially saponified polyvinyl acetate were added.
50 g of 2,2'azobis2,4-dimethylvaleronitrile were charged, and while stirring, 1.5 kg of vinyl chloride monomer was charged and heated to 60°C. The pressure at this time was approximately 65% of the saturated vapor pressure. After that, vinyl chloride monomer was successively added to maintain this pressure, but when the vinyl chloride monomer was added after 10 hours, the pressure rose, so the reaction was continued for another 8 hours, but the pressure was almost constant. There was no change. After dehydration and drying, a graft copolymer was obtained. The results are shown in Table-2. Comparative Example 4 In the polymerization vessel used in Example 1, 30 kg of pure water, 5 kg of ethylene-vinyl acetate copolymer, 50 g of partially saponified polyvinyl acetate, and 4 g of 2,2'azobis2,4-dimethylvaleronitrile were charged and stirred. while 60
heated to ℃. The pressure at this time was about 55% of the saturated vapor pressure. Thereafter, vinyl chloride molemer was successively added so as to maintain this pressure, and the mixture was allowed to react for 6 hours. Thereafter, 4 g of 2,2'azobis2,4-dimethylvaleronitrile was further added, and the mixture was reacted for 6 hours while maintaining the same pressure. After dehydration and drying, a pellet-like graft copolymer was obtained. Table 2 of the results
Shown below. The vinyl chloride component in the graft copolymer is
The amount was 79%, but approximately 10% of the fine powder containing 95% or more of vinyl chloride was produced as a by-product.

Measured from [Table].
In all of the above examples, graft copolymers [B] with excellent transparency and no variation in the content of the vinyl chloride component were obtained.

Claims (1)

[Claims] 1. A vinyl chloride monomer or a monomer mixture of a vinyl chloride monomer and a monomer copolymerizable with the vinyl chloride monomer in water, a suspension stabilizer, and an oil-soluble starter. The vinyl chloride component or vinyl chloride is polymerized in the presence of 10 to 200 parts by weight of the trunk polymer per 100 parts by weight of the agent and the monomer or monomer mixture at saturated vapor pressure of the vinyl chloride monomer. and a vinyl chloride graft copolymer [A] containing 40 to 70% by weight of a monomer component copolymerizable with vinyl chloride, and then in the presence of the graft copolymer [A], vinyl chloride monomer or , a vinyl chloride monomer and a mixture of a monomer copolymerizable with the vinyl chloride monomer are subjected to suspension polymerization while maintaining the polymerization pressure at 30 to 90% of the saturated vapor pressure of the vinyl chloride monomer. A graft polymerization method, which comprises producing a vinyl chloride graft copolymer [B] containing 50 to 95% by weight of a vinyl chloride component or vinyl chloride and a monomer component copolymerizable with vinyl chloride. 2. The backbone polymer is polyethylene, amorphous polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene-vinyl acetate copolymer,
The graft polymerization method according to claim 1, wherein the graft polymerization method is a polyolefin polymer such as an ethylene-propylene-diene copolymer. 3 The backbone polymer is chloroprene rubber, butyl rubber,
Claim 1 which is a rubber or rubber-containing polymer such as styrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, isoprene rubber, nitrile rubber, etc. Graft polymerization method. 4. The graft polymerization method according to claim 1, wherein the backbone polymer is a condensation polymer such as polyester or polyurethane.