JPH06287202A - Production of vinyl chloride-based copolymer - Google Patents

Abstract

PURPOSE:To obtain the subject copolymer excellent in the delusteredness of and few in fish-eyes on the molding therefrom by charging a polymerizer with vinyl chloride singly or its mixture with a comonomer and a crosslinking agent followed by agitation until a homogeneous system is realized and then by initiating polymerization. CONSTITUTION:A polymerizer is charged with ion-exchanged water, a partially saponified polyvinyl acetate as dispersant and, as polymerization initiator, t- butylperoxyneodecanate and 3,3,5-trimethylhexanoyl peroxide followed by eliminating oxygen from the polymerizer, which is then newly charged with vinyl chloride monomer singly or its mixture with a comonomer and a bisphenol A-modified diacrylate as crosslinking agent followed by agitation for 20min until a homogeneous system is attained. The temperature of the resultant system begins to rise and a polymerization is conducted at 64 deg.C for 6hr, thus affording the objective vinyl chloride-based copolymer capable of giving moldings with the surface of uniform, fine texture and excellent delusteredness and few in fish-eyes.

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 vinyl chloride-based copolymer which is excellent in matting and has less fish eyes because the surface irregularities of a molded product are fine and uniform. More specifically, when copolymerizing vinyl chloride monomer alone or a mixture of vinyl chloride monomer and one or more monomers copolymerizable therewith with a crosslinking agent, they are uniformly mixed before the initiation of polymerization. The present invention relates to a method for producing a vinyl chloride-based copolymer, which is characterized by stirring until the reaction is completed.

[0002]

2. Description of the Related Art Vinyl chloride resins are inexpensive and their molded products are excellent in mechanical properties, weather resistance and oil resistance, and are therefore widely used in various fields. In recent years, high-quality molded products having a matt surface have been favored, and in order to meet these demands, diallyl phthalate, diallylmaleate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, bisphenol A-modified diacrylate, bisphenol. A method has been proposed in which a gel component is formed during polymerization using a cross-linking agent such as A-modified dimethacrylate to obtain a molded article having a matte surface (JP-A-54-80354, JP-A-56-5843, JP-A-56-5843). (Kaisho 61-44883).

[0003]

However, according to the above method, although a molded product having a matte surface can be obtained, there is a problem that fish eyes increase. It is an object of the present invention to provide a vinyl chloride-based copolymer that solves the above problems and is capable of obtaining a molded article having excellent matte properties and less fish eyes.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies by the present inventors, vinyl chloride monomer alone or a mixture of vinyl chloride monomer and one or more monomers copolymerizable therewith and crosslinked It was found that the above problems can be solved by stirring until they are uniformly mixed before copolymerization with an agent, and the present invention has been completed. That is, in the present invention, a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and one or more monomers copolymerizable therewith and a cross-linking agent are charged in a polymerization machine and stirred until they are uniformly mixed. Then, the method for producing a vinyl chloride-based copolymer is characterized in that the polymerization is then started.

A vinyl chloride monomer alone or a mixture of vinyl chloride monomer and one or more monomers copolymerizable therewith and a cross-linking agent are charged in a polymerization machine and stirred until they are uniformly mixed, Then, as a method for initiating the polymerization, for example, (1) after charging water into the polymerization machine to deoxygenate the inside of the polymerization machine, vinyl chloride monomer alone or one or more vinyl chloride monomers copolymerizable therewith may be used. A method of charging a mixture of monomers and a cross-linking agent, stirring until they are uniformly mixed, and then initiating polymerization, (2) vinyl chloride monomer alone or vinyl chloride monomer in a previously deoxygenated polymerization machine A mixture of a body and one or more monomers copolymerizable therewith and a crosslinking agent are charged,
A method of stirring until they are uniformly mixed, then charging deoxidized water in advance and initiating polymerization, and the like can be considered, but the method is not particularly limited thereto.

The present invention can be applied to any of the conventionally known polymerization methods such as suspension polymerization method, emulsion polymerization method, bulk polymerization method and solution polymerization method. From the viewpoint of cost, the suspension polymerization method is preferable.

The cross-linking agent used in the present invention is diallyl phthalate, diallylmaleate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, bisphenol A modified diacrylate, bisphenol A modified dimethacrylate, etc. The above is used in combination. The amount of the cross-linking agent used is not particularly limited, but is 0.0 per 100 parts by weight of the monomer.
01 to 15 parts by weight is suitable.

The polymerization temperature in suspension polymerization is not particularly limited, but is preferably 20 to 80 ° C. It is also possible to change the polymerization temperature during the polymerization. The polymerization initiator used in the suspension polymerization is not particularly limited as long as it is usually used for the polymerization of vinyl chloride resin, and for example, lauryl peroxide, 2-ethylhexyl peroxydicarbonate, isopropyl peroxydicarbonate. , Isobutyryl peroxide, 3,3,5-trimethylhexanoyl peroxide, t-butylperoxypivalate, t-butylperoxyneodecanate and other organic peroxides, azobisisobutyronitrile, azobis Examples thereof include azo compounds such as valeronitrile, and these can be used alone or in combination of two or more kinds. Further, it is possible to add these polymerization initiators on the way. The dispersant used in the suspension polymerization is not particularly limited, and for example, partially saponified polyvinyl acetate, methyl cellulose, hydroxypropoxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyvinylpyrrolidone, a copolymer of maleic anhydride and methyl vinyl ether, gelatin, and casein. Well-known dispersants such as organic polymer dispersants such as starch and inorganic dispersants such as talc, calcium sulfate and calcium phosphate can be used alone or in combination of two or more kinds.
Further, it is possible to add these dispersants during the polymerization.

The monomer used in the present invention is a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith. As the monomer copolymerizable with vinyl chloride, vinyl esters such as vinyl acetate, vinyl ethers such as methyl vinyl ether, acrylic acid or methacrylic acid and its ester, maleic acid or phthalic acid and its ester or anhydride, Monomers such as aromatic vinyl compounds, vinylidene halides and monoolefins are exemplified, and these are used alone or in combination of two or more kinds. In addition, there is no problem in performing operations such as adding these monomers in the middle, depending on the reactivity ratio of these monomers and the molecular design of the copolymer finally obtained. Can be appropriately performed.

[0010]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but these do not limit the present invention in any way. In the following description, the physical properties and the matte surface were evaluated according to the following methods. (1) Average particle diameter The average particle diameter was calculated from the point where the cumulative passage rate of each sieve was 50% by weight using standard sieves of 60, 80, 100, 120, 145 and 200 mesh. (2) Porosity Mercury injection type porosimeter (5
-7118 type), absolute pressure 31-1011 PSI
The porosity was determined by measuring the volume of mercury injected per 100 g of the vinyl chloride polymer during (pore diameter: 0.17 to 5.8 μm). (3) Fish Eyes 50 parts by weight of a vinyl chloride polymer obtained by polymerization, 50 parts by weight of "Kanevinyl S1008 (registered trademark, manufactured by Kanebuchi Chemical Industry Co., Ltd.)", 6 parts by weight of a plasticizer (DOP), tin. After blending 5 parts by weight of the system stabilizer and 0.5 part by weight of the lubricant "WAX-OP (manufactured by Hoechst Japan KK)", 40 mm
T-die extrusion (die temperature: 200 ° C., sheet thickness: 120 μm) was performed using an extruder, and the number of transparent particles in 1 m ^{2 of} the sheet was shown.

Example 1 A polymerization machine having an inner volume of 1500 liters was charged with 200 ion-exchanged water.
Parts by weight, 0.2 part by weight of partially saponified polyvinyl acetate as a dispersant, 0.02 part by weight of t-butylperoxyneodecanate as a polymerization initiator, and 0.02 part by weight of 3,3,5-trimethylhexanoyl peroxide. After deoxidizing the inside of the polymerization machine, 100 parts by weight of vinyl chloride monomer and 1.0 part by weight of bisphenol A-modified diacrylate as a cross-linking agent were charged and stirred for 20 minutes to mix them uniformly, then Polymerization was carried out at a polymerization temperature of 64 ° C. after raising the temperature. After 6 hours from the start of heating, the unpolymerized monomer was recovered to complete the polymerization, and the resulting slurry was dehydrated and dried in a hot air dryer at 55 ° C. for 18 hours to obtain an average particle size, porosity and fish eye. Was used for each measurement.

Example 2 In Example 1, ion-exchanged water was not initially charged, but a dispersant and a polymerization initiator were charged, and after deoxidizing the inside of the polymerization machine, 100 parts by weight of vinyl chloride monomer and a crosslinking agent bisphenol A modified. The same method as in Example 1 except that 1.0 part by weight of diacrylate was charged, stirred for 20 minutes and uniformly mixed, and then deoxidized ion-exchanged water at 60 ° C. was charged and polymerization was started by heating. Polymerization was performed and dried, and the physical properties of the obtained polymer were measured.

Comparative Example 1 Polymerization and drying were carried out in the same manner as in Example 1 except that stirring was not carried out for 20 minutes before starting the temperature rise, and the physical properties of the obtained polymer were measured.

[0014]

[Table 1]

[0015]

EFFECT OF THE INVENTION According to the present invention, a vinyl chloride copolymer having excellent mattness of a molded article and greatly improved fish eye can be obtained.

Claims (3)

[Claims] 1. A polymerization machine is charged with vinyl chloride monomer alone or a mixture of vinyl chloride monomer and one or more monomers copolymerizable therewith and a crosslinking agent, and stirred until they are uniformly mixed. And then initiating the polymerization, a method for producing a vinyl chloride-based copolymer. 2. A vinyl chloride monomer alone or a mixture of vinyl chloride monomer and one or more monomers copolymerizable therewith and a cross-linking agent after charging the polymerization machine with water to deoxidize the inside of the polymerization machine. Is added, the mixture is stirred until they are uniformly mixed, and then the polymerization is started, which is a method for producing a vinyl chloride-based copolymer. 3. A vinyl chloride monomer alone or a mixture of vinyl chloride monomer and one or more monomers copolymerizable therewith and a cross-linking agent are charged in a deoxidized polymerization machine, and these are homogeneous. A method for producing a vinyl chloride-based copolymer, which comprises stirring until the mixture is mixed with water, and then adding deoxygenated water to start polymerization.