JPS6143611A - Preparation of vinyl chloride resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin having stabilized particle size, by coagulating an acrylic polymer under cooling at a specific temperature or below, and graft copolymerizing vinyl chloride with the polymer by the suspension polymerization method. CONSTITUTION:An acrylic polymer latex, e.g. copolymer latex consisting essentially of (meth)acrylate, and containing if necessary a copolymerizable monomer, e.g. styrene, is cooled to <=10 deg.C and coagulated. Graft copolymerization of vinyl chloride is then carried out by the suspension polymerization method to give the aimed resin.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for producing vinyl chloride resin, and more specifically, the present invention relates to a method for producing vinyl chloride resin, and more specifically, a method for producing vinyl chloride resin, in which vinyl chloride is kraft copolymerized with acrylic polymer latex and has a stable particle size. The present invention relates to a method for producing vinyl chloride resin.

[Conventional technology]

Vinyl chloride resin has excellent physical and mechanical properties, so it has many uses such as hard, semi-hard, and soft. However, vinyl chloride homopolymers have the drawback of poor impact resistance and weather resistance when used for hard applications.

These drawbacks are usually improved by blending various elastomers with vinyl chloride homopolymer. Although this method can improve impact resistance, it has the disadvantage that weather resistance and flexural modulus are reduced.

Furthermore, vinyl chloride graft copolymers obtained by graft copolymerizing vinyl chloride onto acrylic polymers are known to have excellent processability, impact resistance, weather resistance, and flexural modulus. One way to obtain this vinyl chloride graft copolymer is to graft copolymerize vinyl chloride onto acrylic rubber, but this method involves a step of cutting the rubber into small pieces, then expanding the cut rubber into vinyl chloride, Alternatively, a step of dissolving is required, and therefore there is a problem in workability, which is disadvantageous for industrial implementation.

As a method for solving the above problems, there is a method of graft copolymerizing vinyl chloride onto an acrylic polymer latex. If this method is adopted, workability is improved, but the polymerization mode is suspension polymerization in the presence of an emulsifier contained in the acrylic polymer latex, so a large amount of dispersant is required, and the particle size It is difficult to obtain a product with stable particle size.

[Problem that the invention seeks to solve]

The present inventor aimed to obtain a product with stable particle size using an emulsion-suspension polymerization method, that is, a method in which an acrylic polymer latex obtained by emulsion polymerization is graft-copolymerized with vinyl chloride using a suspension polymerization method. shall be.

[Means for solving problems]

As a result of intensive research to achieve the above object, the present inventors found that acrylic polymer latex was solidified by cooling to below 0°C inside and/or outside the graft copolymerization reaction tank, and then chlorinated. It has been discovered that a product with stable particle size can be obtained by graft copolymerizing vinyl using a suspension polymerization method, leading to the present invention.

That is, in the present invention, when producing a graft copolymer by graft copolymerizing vinyl chloride onto an acrylic polymer, the acrylic polymer latex is heated at 10° C. or lower in the graft copolymerization reaction tank and/or outside the reaction tank. This is a method for producing a vinyl chloride resin having a stable particle size, which is characterized in that the resin is cooled to a temperature of 100°C, solidified, and then graft copolymerized with vinyl chloride using a suspension polymerization method.

The acrylic polymer latex used in the present invention is a copolymer latex mainly composed of alkyl acrylate and/or alkyl methacrylate, and optionally containing other copolymerizable monomers.

Examples of the alkyl acrylate and alkyl methacrylate include methyl acrylate, ethyl acrylate, n-propyl acrylate, 1so-butyl acrylate, n-butyl acrylate), n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, Examples include n-decyl acrylate, n-dodecyl acrylate, lauryl acrylate and their methacrylates.

In addition, copolymerizable monomers include monofunctional monomers such as olefins such as ethylene, propylene, and hexene, aromatic vinyls such as styrene, α-methylstyrene, and vinyltoluene, and acrylonitrile and methacrylates. Unsaturated nitriles, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as phthyl vinyl ether and lauryl vinyl ether, polyfunctional monomers such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, Ethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, 1.3
- Acrylates or methacrylates of mono- or polyalkylene glycols such as propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, etc.
L/-ts, diallyl phthalate, diallyl maleate,
Examples include di- or triallyl compounds such as diallyl fumarate, diallyl succinate, and triallyl isocyanurate, and divinyl compounds such as divinylbenzene and butadiene.

The alkyl acrylate, alkyl methacrylate, and copolymerizable monomers may be used alone or in combination of two or more to obtain a latex.

The amount of acrylic polymer latex added is also determined depending on the intended use of the final product.

The acrylic polymer latex used in the present invention is obtained by emulsion polymerization, and the average particle size of the latex is preferably about 0.01 to 10 μm.

As a method for obtaining latex by a general emulsion polymerization method, for example, pure water, an anionic emulsifier, and a water-soluble polymerization initiator are placed in a jacketed polymerization reactor.

is charged, the air inside the can is removed, and then monomers copolymerizable with alkyl acrylate and/or alkyl methacrylate are charged, and after emulsification, the inside of the can is heated by a jacket to start the reaction.

The reaction is exothermic, and the internal temperature is controlled by a jacket as necessary. After the reaction is completed, unreacted monomers are removed from the can to obtain an acrylic polymer latex. The method of charging into the polymerization reactor is not limited. Further, if necessary, a latex particle size adjusting agent, a catalyst decomposition accelerator, etc. may be added to control the reaction.

The acrylic polymer latex is approximately 50wt by the above method.
% concentration, but due to manufacturing and handling issues,
Concentrations of 10 to 30 wt% are advantageous.

The method of cooling the acrylic polymer latex to 10°C or lower in the present invention is to first cool the acrylic polymer latex to 10°C or lower to solidify it outside the reaction tank in which the graft copolymerization is carried out, and then add the acrylic polymer slurry inside the reaction tank. There are two methods: one method is to put the acrylic polymer latex into the reaction tank in which the graft copolymerization is to be carried out, and then the acrylic polymer latex is cooled and solidified from the jacket section. In addition, dry ice is added to the acrylic polymer latex.
You can also solidify it by adding ice or the like.

When carrying out the aqueous suspension polymerization method, the amount of water used for the total amount of the copolymer of the backbone polymer and the vinyl chloride monomer is 1 to 1.
It is 5 times, preferably 1 to 3 times.

A method for obtaining a graft copolymer resin by the suspension polymerization method of the present invention includes, for example, placing pure water, a radical polymerization initiator, and, if necessary, a degree of polymerization regulator in a jacketed polymerization reactor.
Add the solidified acrylic polymer slurry while stirring,
The air in the end is then evacuated and a turbidity stabilizer such as hydroxypropyl methyl cellulose is introduced, followed by the vinyl chloride, along with other vinyl compounds as required.

The inside of the rear end is heated by a jacket to start graft copolymerization. Graft copolymerization is an exothermic reaction, and the internal temperature is controlled by a jacket if necessary. After the reaction is completed, unreacted vinyl chloride is removed from the can to obtain a slurry of graft copolymer resin. The slurry is dehydrated and dried in a conventional manner to obtain a graft copolymer resin.

In carrying out the present invention, it is advantageous to carry out the graft copolymerization by a radical polymerization method, and the radical polymerization initiators used for this purpose include lauroyl peroxide, tert-butyl peroxypivalate, diisopropyl peroxydi Carbonate, organic peroxides such as dioctyl peroxydicarbonate, 2.2+-
Azobisisobutyronitrile, 2*2'-azobis-2
, 4-dimethylvaleronitrile and the like, and water-soluble polymerization initiators such as potassium persulfate and ammonium persulfate. The amount of these polymerization initiators used is 0.0 per 100 parts by weight of vinyl chloride.
The amount is preferably 0.05 to 1.0 parts by weight.

Dispersants include methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, polyvinyl alcohol and its partially saponified products, gelatin, polyvinylpyrrolidone, starch,
Examples include maleic anhydride-styrene copolymers, which may be used alone or in combination. The amount added is
It is 0.01 to 1.0 parts by weight per ioo parts by weight of vinyl chloride.

Furthermore, in the present invention, a chain transfer agent used in conventional methods for polymerizing vinyl monomers may be added in an amount of 0.001 to 10 parts by weight per 100 parts by weight of vinyl chloride.

The graft copolymer resin obtained by the method of the present invention has a stable average particle size of 90 to 120 μm and is very easy to handle during processing.

The graft copolymer resin obtained by the method of the present invention contains the usual stabilizers, lubricants, and
By blending processing aids, antioxidants, fillers, ultraviolet absorbers, pigments, etc., it can be used in normal molding processes, and is suitable for building materials due to its excellent impact resistance and weather resistance. used for.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples.

Reference Example-1 (Manufacturing example of acrylic latex) 2000 kg of deionized water is placed in a polymerization machine with an internal volume of 5 m3 and equipped with a stirring blade.
, anionic emulsifier 7.0 to 9, ammonium persulfate 0
．． 7kg, n-methylac')V-)700kg,
1.3-butylene glycol dimethacrylate) 35k
After replacing the air inside with nitrogen, polymerization was carried out at 60°C. Fifteen hours after the start of polymerization, the internal temperature began to rise rapidly, so heat was removed from the jacket and a backflow condenser, and the reaction was continued for an additional 10 hours, then the polymerization reaction was stopped.

The concentration of the obtained latex was 25%, and the particle size was 0.07 μm.

Example-1 A jacketed container with an internal volume of 11 equipped with a stirring blade was
840 g (solid content: 2109) of an acrylic polymer latex having the composition shown in the table and having a concentration of 25% was added, and the jacket portion was cooled to 0° C. while stirring, and the acrylic polymer latex solidified. This acrylic polymer slurry,
Deionized water 27 cm was added to a polymerization machine with an internal volume of 7 cm equipped with stirring blades.
00g, partially saponified polyvinyl alcohol 1.0g
, Methylcetate/L/Rose 1.09.2.2'-azobisisobutyronitrile 0.45!7, and after removing the air inside, 1.29(L) of vinyl chloride was charged, 6
Polymerization was carried out at 0°C, and 12 hours after the start of polymerization, the internal pressure of the polymerization machine decreased to 6.5 kg/crd, so the polymerization reaction was stopped. After removing the unreacted vinyl chloride monomer, the slurry was dehydrated and dried by a conventional method to obtain 12207 white powder particles.

The average particle size of this white powder was 98 μm, and the particle size distribution was also narrow and stable.

Example-2 In a polymerization machine equipped with a stirrer and having an internal volume of 71, 60% of acrylic polymer latex having a composition shown in Table 1 and having a concentration of 15% was added.
09 (solid content: 90 g), and while stirring until the latex solidified, 100 g of crushed dry ice was added. The final temperature was 10°C. After that, deionized water 27009, polyvinyl alcohol partially saponified product 0
．． 89, methyl cellulose 0.8! 7.2,21-
Azobis-2,4-dimethylvaleronitrile 0.075
9.2,21-azobis-2,4-dimethylvaleroni)
After 0.24 g of IJ was added and the air inside was removed, 1.41 l of vinyl chloride was charged and polymerization was carried out at 57°C. After 11 hours from the start of polymerization, the internal pressure of the polymerizer was 6.5 kg/crd.
The polymerization reaction was stopped. After removing the unreacted vinyl chloride monomer, the slurry was dehydrated and dried by a conventional method to obtain 12,009 white powder particles.

The average particle size of this white powder was 100 μm, and the particle size distribution was also narrow and stable.

Comparative Example-1 In Example-1, the results were increased to 2.3 g of partially saponified polyvinyl alcohol and 2.3 g of methyl cellulose, and the acrylic polymer latex was not coagulated.
Polymerization was carried out in the same manner as in Example 1'' to obtain 1170 g of white powder particles.

This white powder had a large average particle size of 250 μm and a wide particle size distribution.

Comparative Example 2 In klJllll-1, polymerization was carried out in the same manner as Comparative Example 1, except that 2.4 g of partially saponified polyvinyl alcohol and 2.47 methyl cellulose were used.
210 g of white powder particles were obtained.

The average particle size of this white powder was 78 μm, and the particle size distribution was wide.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 2, except that in Example 2, the partially saponified polyvinyl alcohol and methyl cellulose were increased to 2.0 g and 2.0 g of methyl cellulose, and the acrylic polymer latex was not coagulated. 1150 particles of white powder were obtained.

The average particle size of this white powder was 200 μm, and the particle size distribution was wide.

Comparative Example-4 Polymerization was carried out in the same manner as Comparative Example-3 except that 2.1 g of partially saponified polyvinyl alcohol and 2.1 g of methyl cellulose were used in Comparative Example-3.
g of white powder particles were obtained.

The average particle size of this white powder was 77 μm, and the particle size distribution was wide.

The results of the above Examples and Comparative Examples are summarized in Table 1. In addition, the particle size distribution is 60.8 from the top of the JIS standard sieve.
0, 100, 150, 200, 270 meshes and saucers are stacked in this order, and samples 5 and 1 are placed on top of the sieve, and after being vibrated for 15 minutes using a sieve shaker, The proportion of resin present on the top was measured and expressed in weight %.The average particle size was determined by the cumulative total of the remaining percentage of each mesh on the horizontal axis of the regular cloth, and the opening of each mesh (on the vertical axis).
Plot the eye opening (μm) with a cumulative total of 50%
It was expressed as

〔Effect of the invention〕

In the method of the present invention, since the acrylic polymer latex is coagulated once, the particle size distribution of the obtained vinyl chloride graft copolymer particles is sharp, and the average particle size is also sufficiently large. In good condition.

On the other hand, when coagulation is not performed, a large amount of dispersant is required, and as seen in the comparative example, even a slight difference in the dispersant causes extreme changes in the particle size distribution and average particle diameter.

Claims (1)

[Claims] 1) When producing a graft copolymer by graft copolymerizing vinyl chloride onto an acrylic polymer, the acrylic polymer latex is cooled to 10°C or less and coagulated, and then vinyl chloride is added using a suspension polymerization method. A method for producing vinyl chloride resin, which comprises graft copolymerization.