JP2002308918A - Reaction inhibiting agent for radical polymerization of vinyl monomer and method for producing vinyl polymer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reaction inhibiting agent for radical polymerization of a vinyl monomer which can be used to add even under a cold condition without the fear that the agent may be hardened to block a pipe; and to provide a method for producing a vinyl polymer using the same. SOLUTION: The reaction inhibiting agent for radical polymerization of the vinyl monomer comprises a compound represented by formula (1) [wherein R is an 8-10C straight alkyl group]. The reaction inhibiting agent is added into the system of the polymerization of the vinyl monomer by a radical reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reaction inhibitor for radical polymerization of vinyl monomers and a method for producing a vinyl polymer using the same.

[0002]

2. Description of the Related Art Conventionally, in a radical polymerization reaction of a vinyl monomer, a reaction inhibitor (also referred to as a reaction inhibitor) has been added to the polymerization system. System compounds, sulfur compounds, N-oxide compounds, phosphorus compounds, unsaturated hydrocarbon compounds and the like are known. Among them, phenolic compounds include, for example, 2,2-di- (4'-hydroxyphenyl) propane, hydroquinone, p-methoxyphenol, t-butylhydroxyanisole, n-octadecyl-3- (4
-Hydroxy-3,5-di-t-butylphenyl) propionate, t-butylhydroquinone, 2,5-di-t-butylhydroquinone, 4,4'-butylidenebis- (3-methyl-6-t-butyl) Phenol, 3,5-di-t-butyl-4-hydroxytoluene, 2,2'-methylene-bis-
(4-ethyl-6-t-butyl) phenol, triethylene glycol bis [3- (3-t-butyl-5-methyl-4
-Hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4
-Hydroxyphenol) propionate], t-butylcatechol, 4,4'-thiobis- (6-t-butyl) -m
-Cresol, tocopherol and the like are known.

[0003] These reaction inhibitors are added to the polymerization system prior to the initiation of polymerization to reduce fish eyes in the resulting polymer (Japanese Patent Application Laid-Open Nos. 48-49990 and 60-50366). Publication), and added during the polymerization reaction to suppress heat kick, or added at the end of the polymerization reaction to prevent post-polymerization or to prevent deterioration of anti-initial coloring property due to heat history (US (Patent No.3642756, JP-A-57-185302 and JP-A-62-503). It is also used as an emergency reaction terminator in abnormal reactions. Among them, especially 2,2-di- (4'-hydroxyphenyl)
Propane has been used at the end of the polymerization reaction because of its excellent ability to suppress the reaction, good quality of the resulting polymer, and small amount of scale adhered to the polymerization vessel.

[0004] However, 2,2-di- (4'-hydroxyphenyl) propane is a solid at ordinary temperature, and unless it is used after being dissolved in an organic solvent such as methanol, the charging operation from the charging line to the polymerization vessel is difficult. is there. In this method, since an organic solvent is used, the worker inhales steam to cause not only physical injury but also environmental pollution.

[0005] In place of 2,2-di- (4'-hydroxyphenyl) propane, Japanese Patent Publication No. 7-13041 discloses that 2,6-di-t-butyl-4-sec-sec. Butylphenol is disclosed. Since this is a liquid at room temperature, the charging operation from the charging line to the polymerization vessel can be performed without using a solvent.

[0006]

However, the above-mentioned 2,6-
Di-t-butyl-4-sec-butylphenol has a freezing point of 1
Since it is 8 to 20 ° C., when the outside air temperature is low, that is, when it is used at 10 ° C. or less, it becomes a supercooled state, and as a result, the reaction inhibitor is easily crystallized and the charging pipe may be blocked. . Therefore, when the operation of charging from the charging line to the polymerization reactor is performed when the outside air temperature is low, it must be used after dissolving it in an organic solvent such as methanol, which causes problems such as physical injury to workers and environmental pollution. It is not enough to respond to

Further, in the case where the reaction inhibitor solidifies in a cold state and the charged pipe is blocked, measures are taken to prevent the blockage of the pipe by heating the charged pipe to melt the solidified reaction inhibitor. However, if the heating method is intense,
There is a possibility that the reaction inhibitor may be reduced in its ability to suppress the reaction due to thermal decomposition, or the polymer obtained by coloring the reaction inhibitor may be colored. In addition, even in consideration of workability, there is a risk that the heating operation in a heating device facility or the like becomes complicated.

Accordingly, an object of the present invention is to provide a reaction for radical polymerization of a vinyl monomer which does not cause problems such as solidification of the reaction inhibitor and blockage of piping even when the operation of charging the reaction inhibitor is carried out in cold weather. An object of the present invention is to provide an inhibitor and a method for producing a vinyl polymer using the same.

[0009]

As a result of intensive studies, the present inventors have found that a reaction inhibitor for radical polymerization of a vinyl monomer, which will be described later, solves the above-mentioned problems. Reached the present invention.

That is, the present invention firstly provides the following general formula (1)

[0011]

Embedded image

Wherein R is a straight-chain alkyl group having 8 to 10 carbon atoms. And a reaction inhibitor for radical polymerization of vinyl monomers characterized by having a compound represented by the formula:

Second, in the polymerization of a vinyl monomer by a radical reaction, the following general formula (1)

[0014]

Embedded image

Wherein R is a straight-chain alkyl group having 8 to 10 carbon atoms. A method for producing a vinyl-based polymer, characterized by adding a reaction inhibitor represented by the formula (1) to a polymerization system.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The reaction inhibitor for radical polymerization of a vinyl monomer according to the present invention is represented by the above general formula (1) wherein R represents 8 carbon atoms.
~ 10 linear alkyl groups. And a compound represented by the general formula (1), wherein R is an n-nonyl group, particularly, 2,6-di-tert-butyl-4-.
n-Nonylphenol is preferred.

The reaction inhibitor of the present invention has a melting point of less than -30 ° C and is lower than that of 2,6-di-t-butyl-4-sec-butylphenol. Even in the case below, it is difficult to be in a supercooled state, and the liquid is maintained without being crystallized. Therefore, even in the cold season, the pipe for charging the reaction inhibitor is not blocked. Therefore, it is possible to introduce the reaction inhibitor into the polymerization system without using an organic solvent such as methanol or toluene and without having to heat the feed pipe.

The reaction inhibitor of the present invention is used for a radical polymerization reaction of a vinyl monomer. As the vinyl monomer, for example, vinyl halide or vinylidene halide such as vinyl chloride, vinyl bromide, and vinylidene chloride; at least an acrylate ester such as methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, and cyanoethyl acrylate; Polymerizable olefinic monomer having one terminal group CH ₂ CC <; vinyl acetate; methacrylic acid ester such as methyl methacrylate, butyl methacrylate; styrene including α-methylstyrene, vinyltoluene, chlorostyrene, etc. And styrene derivatives; vinyl naphthalene; diolefins including butadiene, isoprene, chloroprene, and the like; and mixtures of these monomers with other copolymerizable olefin monomers; and other known polymerizable olefins. Inmonoma and the like.

The reaction inhibitor of the present invention can be applied irrespective of the type of polymerization as long as it is a radical polymerization reaction of a vinyl monomer, such as suspension polymerization, emulsion polymerization, bulk polymerization, and fine suspension. It can be used in any type of polymerization such as polymerization.

Depending on the purpose of use, the reaction inhibitor may be used in at least one of before, during and after the polymerization.
It is added to the polymerization system in one stage, and the amount added is generally about 0.0005 to 0.5 part by weight per 100 parts by weight of the vinyl monomer. More specifically, when added before the start of polymerization for the purpose of reducing the produced polymer fish eye, the reaction inhibitor 0.0005 per 100 parts by weight of the vinyl monomer.
~ 0.005 parts by weight is preferred. This case is effective when the aqueous medium is previously heated and charged. When the polymerization reaction is completed at the time of reaching the predetermined polymerization conversion rate, when added at the end of polymerization for the purpose of preventing the post-polymerization after that, the reaction inhibitor 0.005 per 100 parts by weight of the charged vinyl monomer. ~ 0.05
Parts by weight are preferred. Furthermore, when a reaction inhibitor is added to the polymerization system for the purpose of completely stopping the polymerization reaction in an emergency, the reaction inhibitor is preferably 0.2 to 0.5 part by weight per 100 parts by weight of the charged vinyl monomer.

The method of adding the reaction inhibitor of the present invention into the polymerization system is preferably directly added to the polymerization system as it is in the form of an undiluted solution, because it meets the significance of the present invention, but is appropriately selected according to the type of polymerization. be able to. For example, the reaction inhibitor of the present invention may be dissolved and diluted with a solvent such as methanol or toluene, or may be added after dilution, using an emulsifier, a suspending agent, or the like,
The reaction inhibitor may be dispersed in water to prepare a suspension, which may be charged into the polymerization system and added.

Next, the method for producing the vinyl polymer of the present invention will be described for the case of suspension polymerization.

Suspension polymerization in an aqueous medium is usually carried out at a temperature of 0 to 100 ° C., particularly preferably 30 to 70 ° C., in the presence of a known polymerization initiator and dispersant. The dispersant and polymerization initiator used here are not particularly limited, and those conventionally used for polymerization of vinyl monomers are used. Examples of the dispersant include water-soluble cellulose ethers such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose; water-soluble and oil-soluble partially saponified polyvinyl alcohol; acrylic polymers; and water-soluble polymers such as gelatin; Laurate, sorbitan triolate, glycerin tristearate, oil-soluble emulsifiers such as ethylene oxide propylene oxide block copolymer, polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate, water-soluble emulsifiers such as sodium laurate, and the like. These may be used alone or in combination of two or more. The amount of these dispersants is not particularly limited, and is usually 0.01 to 100 parts by weight of the monomer.
Used up to 5 parts by weight.

Examples of the polymerization initiator include percarbonate compounds such as diisopropylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, and diethoxyethylperoxydicarbonate; t-butylperoxyneodecanate; Perester compounds such as t-butylperoxypiparate, t-hexylperoxypiparate, α-cumylperoxyneodecanate, 2,4,4-trimethylpentyl-2-peroxy-2-neodecanate, acetylcyclohexylsulfonyl Peroxide, 2,4,4-trimethylpentyl-2
Peroxides such as peroxyphenoxyacetate, 3,5,5-trimethylhexanoyl peroxide and isobutyryl peroxide, azobis-2,4-dimethylvaleronitrile, azobis (4-methoxy) -2,4-dimethyl Azo compounds such as valeronitrile; and furthermore, ammonium persulfate, hydrogen peroxide and the like. These may be used alone or in combination of two or more. The amount of these polymerization initiators is not particularly limited, and is usually 0.01 to 1 part by weight based on 100 parts by weight of the monomer.

Other conditions for suspension polymerization in an aqueous medium,
For example, a method for charging and degassing an aqueous medium into a polymerization vessel, a method for charging a vinyl monomer, and in some cases, other comonomers, a dispersant, a polymerization initiator, and the like, the charging ratio and the like thereof are not particularly limited and are usually performed. Conditions may be used, and the polymerization system may optionally include a polymerization degree regulator, a chain transfer agent, a pH regulator, a gelling improver, an antistatic agent, an antioxidant, It is also optional to add a scale adhesion inhibitor and the like.

[0027]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 800 kg of deionized water, 210 g of partially saponified polyvinyl alcohol as a dispersant, and hydroxypropyl methylcellulose were placed in a polymerization vessel equipped with a stirrer and a jacket having an internal volume of 2000 L.
80g was charged. Next, after degassing until the internal pressure of the polymerization reactor became 0.013 MPa, 720 kg of a vinyl chloride monomer was charged. With stirring, diethylhexyl peroxydicarbonate
300 g, 130 g of t-butyl peroxyneodecanate and 30 g of cumylperoxyneodecanate were press-fitted, and simultaneously heated to 57 ° C. through hot water in a jacket, followed by polymerization while maintaining the temperature.

When the internal pressure of the polymerization reactor dropped to 0.6 MPa, 100 g of 2,6-di-tert-butyl-4-n-nonylphenol was added as a reaction inhibitor from a charging line, and unreacted monomers were recovered. The slurry as a reaction mixture was taken out of the polymerization vessel and dehydrated by a centrifuge. The dehydrated cake was dried at 70 ° C. for 3 hours using a batch fluidized drier to obtain a product. The outside temperature at that time was around 5 ° C.

Example 2 At an ambient temperature of about 5 ° C., a vinyl chloride monomer was polymerized in the same manner as in Example 1, and when the internal pressure of the polymerization reactor was reduced to 0.6 MPa, a reaction inhibitor was used. , 6-di-tert-butyl-4
After 150 g of -n-nonylphenol was added from the charging line, a product was obtained in the same manner as in Example 1.

COMPARATIVE EXAMPLE 1 At an ambient temperature of about 5 ° C., a vinyl chloride monomer was polymerized in the same manner as in Example 1. When the internal pressure of the polymerization reactor dropped to 0.6 MPa, a reaction inhibitor was used. , 6-Di-t-butyl-4-s
After diluting 100 g of ec-butylphenol with 500 g of methanol and adding it from a charging line, a product was obtained in the same manner as in Example 1.

COMPARATIVE EXAMPLE 2 At an outside air temperature of about 5 ° C., a vinyl chloride monomer was polymerized in the same manner as in Example 1. When the internal pressure of the polymerization reactor dropped to 0.6 MPa, a reaction inhibitor was used. , 6-Di-t-butyl-4-s
An attempt was made to add 100 g of ec-butylphenol from the charging line without diluting with methanol, but 2,6-di-t-butyl-
Since 4-sec-butylphenol was solidified, the charging pipe was blocked and could not be charged. Then, after recovering the unreacted monomer, a product was obtained in the same manner as in Example 1.

Each of the obtained products was evaluated for physical properties and characteristics as follows. Table 1 shows the results. (Bulk specific gravity) Measured according to JIS K-6721. (Plasticizer absorption amount) Glass fiber is packed in the bottom of an aluminum alloy container having an inner diameter of 25 mm and a depth of 85 mm, and 10 g of a sample resin is sampled and charged. To this, add 15 cc of DOP (dioctyl phthalate) and leave it for 30 minutes to allow the DOP to fully penetrate. Thereafter, excess DOP was centrifuged at an acceleration of 1500 G, and the amount of DOP adsorbed on the resin was determined and expressed as a value per 100 g of the resin.

(Plasticizer absorbency) 400 g of a vinyl chloride polymer was put into a planetary mixer (jacket temperature: 83 ° C.) of a plastic coder manufactured by Plavender and heated for 4 minutes while kneading at 60 rpm. Was added. DOP
The time from the time of addition to the time when the kneading torque of the planetary mixer was minimized was defined as a dry-up time, and was used as an index of plasticizer absorbency.

(Anti-Initial Coloring Property) 1.5 g of a tin-based stabilizer and 50 g of DOP were blended with 100 g of a vinyl chloride polymer and kneaded using a two-roll mill at 160 ° C. for 5 minutes to form a 0.8 mm thick sheet. . Next, cut and stack this sheet, 4x4x1.5c
The sample was placed in a m mold, heated at 160 ° C. and 6.5 to 7 MPa, and pressure molded to prepare a measurement sample. For this measurement sample, a JIS-Z8730 (198
Determine the lightness index L in the hunter color difference meter described in 0), a
And b values were measured. Further, the anti-initial coloring property was evaluated based on the following results based on the measurement results. ：: good ×: bad

[0036] The composition prepared according to the above formulation was kneaded at 140 ° C. for 5 minutes using 6 rolls, and then formed into a sheet having a width of 15 cm and a thickness of 0.22 mm. The number of transparent particles was counted on the entire surface of the obtained sheet, and this was defined as a roll fish eye.

[0037]

[Table 1]

A: 2,6-di-tert-butyl-4-n-nonylphenol B: 2,6-di-tert-butyl-4-sec-butylphenol

From the results shown in Table 1, according to the production method of the present invention, the reaction inhibitor can be introduced into the polymerization vessel as it is, without blocking the pipe for charging the reaction inhibitor, even in cold conditions. It was confirmed that it was possible to produce a vinyl chloride polymer having a quality not inferior to that of the method described in the above.

[0040]

According to the present invention, the reaction inhibitor for radical polymerization of a vinyl monomer is used, and according to the method for producing a vinyl polymer of the present invention, the operation such as dilution with an organic solvent can be carried out even in cold conditions. Even without this, the reaction inhibitor can be introduced into the polymerization vessel without blocking the feed pipe, and a vinyl chloride-based polymer of lower quality than the conventional method can be produced. In particular, the method of the present invention is effective when the outside air temperature is 10 ° C. or less.

Continuation of the front page F term (reference) 4J011 NA03 NB03 4J100 AB00P AB03P AB04P AB08P AC03P AC04P AC12P AG04P AL03P AL04P AL08P AS02P AS03P AS07P BA40P CA01 FA06

Claims (5)

[Claims] [Claim 1] The following general formula (1) [Wherein, R is a straight-chain alkyl group having 8 to 10 carbon atoms. ] A reaction inhibitor for radical polymerization of a vinyl monomer, comprising the compound represented by the formula: 2. The method according to claim 1, wherein the reaction inhibitor is 2,6-di-tert-butyl-4.
The reaction inhibitor for radical polymerization of a vinyl monomer according to claim 1, which is -n-nonylphenol. 3. In the polymerization of a vinyl monomer by a radical reaction, the following general formula (1): [Wherein, R is a straight-chain alkyl group having 8 to 10 carbon atoms. ] A method for producing a vinyl polymer, comprising adding a reaction inhibitor represented by the formula [1] to a polymerization system. 4. The method for producing a vinyl polymer according to claim 3, wherein the vinyl monomer is vinyl chloride. 5. The method according to claim 1, wherein the reaction inhibitor is 2,6-di-tert-butyl-4.
The method for producing a vinyl polymer according to claim 3, which is -n-nonylphenol.