JP2819764B2 - Method for producing diene polymer - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to the polymerization of diene-based monomers, and more particularly, to bulk polymerization of diene-based monomers under a specific catalyst to obtain a diene-based monomer having a high average molecular weight. The present invention relates to a method for producing a polymer.

[Prior Art] As a method for producing a polymer using a diene-based monomer,
Conventionally, several methods are known. Among them, emulsion polymerization, in which a monomer is emulsified in water using an emulsifier to carry out polymerization, is most often used for synthesizing a diene polymer from the viewpoint of easy reaction control, handling properties, and productivity. .

However, the diene polymer produced by emulsion polymerization contains a large amount of residues of an emulsifier, an electrolyte added to stabilize the latex, and a metal salt used for salting of the polymer. . For this reason, it is suitable for vulcanized rubber applications such as hoses, belts and packings.
When used as a material for electric / electronic parts, the metal corrosiveness, particularly the metal corrosiveness when energized, has become a problem.

On the other hand, a solution polymerization method is also widely used as a method for obtaining a diene polymer. However, when a diene polymer is obtained by solution polymerization, if a radical polymerization initiator typified by an organic peroxide is used as a catalyst, the molecular weight does not become sufficiently large, and a high molecular weight polymer cannot be obtained.
For this reason, there is a problem that a material having good mechanical strength cannot be obtained. In addition, in the case of an anionic polymerization catalyst represented by an alkyl lithium or a metal catalyst such as nickel, cobalt, and titanium, if an ethylenically unsaturated monomer copolymerized with a diene monomer has a polar group, polymerization does not proceed, There is a problem that the catalyst metal remains in the polymer. In addition, bulk polymerization has the same problem as solution polymerization.

As described above, a method for obtaining a diene polymer having a small amount of contaminants which adversely affect various uses and a high molecular weight polymer, particularly a copolymer with an ethylenically unsaturated monomer having a polar group, has not been found.

On the other hand, in the electric and electronic fields, from the viewpoint of weight reduction and compactness, more reliable and less corrosive materials are required as materials to be used. There is a need for a polymer with less impurities.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and has as its object to reduce impurities in a polymer, and to have a high-molecular-weight diene-based polymer, In particular, it is an object of the present invention to provide a method for producing a random copolymer with an ethylenically unsaturated monomer having a polar group by a bulk polymerization method.

[Means for Solving the Problems] The present invention relates to a diene monomer or a diene monomer and an ethylenically unsaturated monomer in the presence of a polymerization initiator represented by the following general formula (I). And a method for producing a diene-based polymer, characterized by performing bulk polymerization of

General formula (I) In the formula, R ₁ and R ₂ are the same or different and represent a hydrogen, an alkyl group, a phenyl group, an aralkyl group, a cyano group, a phenoxy group, a hydroxy or alkoxycarbonyl group or a derivative thereof, and R _{3 to} R ₆ are the same or different. Differently, it represents a hydrogen, an alkyl group, a hydroxyl group, an alkoxy group, a carboxylic acid group, an amino group or a derivative thereof.

However, the general formula (I) excludes the case where both R ₁ and R ₂ are phenyl groups and R _{3 to} R ₆ are all hydrogen.

 Hereinafter, the present invention will be described in detail.

In the polymerization initiator represented by the general formula (I),
As R ₁ and R ₂ , hydrogen, phenyl group, cyano group, methyl group, ethyl group, propyl group, butyl group, octyl group, cyclohexyl group, dodecyl group, phenoxy group, various nucleus-substituted phenoxy groups, various carboxylic acids or Examples of the carboxylic acid ester group include R _{3 to} R ₆ as hydrogen, hydroxy, methyl, ethyl, propyl,
Butyl, octyl, methoxy, ethoxy, propoxy, butoxy, carboxylic acid, methyl carboxylate, ethyl carboxylate, propyl carboxylate, butyl carboxylate, amino, diethylamino, diethylaminoxy Group, nitro group, chlorine, bromine and the like.

As the compound represented by the general formula (I), 3,3,4,
4-tetraphenylhexane, 4,4,5,5-tetraphenyloctane, 2,2,3,3-tetraphenylbutane, 1-cyano-2,2,3,3-tetraphenylbutane, tetraphenylsuccinic acid Dinitrile, diethyl tetraphenylsuccinate, 1,2-diphenoxy-1,1,2,2-tetraphenylethane, methyl-2,2,3,3-tetraphenyl-3-cyanopropionate, ethyl-2, 2,3,3-tetraphenyl-3
-Cyanopropionate and the like. One of these compounds may be used alone, or two or more of them may be used in combination.

The amount of the compound represented by formula (I) used as a polymerization initiator is not particularly limited, but is preferably 0.01 to 2 parts by weight based on 100 parts by weight of the monomer. If the amount of the compound is less than 0.01 part by weight, the progress of the polymerization reaction is difficult,
On the other hand, if it exceeds 2 parts by weight, it becomes difficult to control the reaction.

The diene monomer used in the present invention includes 1,3-
Conjugated dienes such as butadiene, isoprene, chloroprene, 1,3-hexadiene, 2-methyl-1,3-butadiene, 2,3-dimethylbutadiene, 2-trimethoxysilyl-1,3-butadiene and 1,3-pentadiene Monomer, ethylidene norbornene, dicyclopentadiene, 1,
Examples thereof include non-conjugated diene monomers such as 4-hexadiene, vinyl (meth) acrylate, allyl (meth) acrylate, diallyl ether, divinyl ether, and ethylene glycol dimethacrylate.

Examples of the ethylenically unsaturated monomers copolymerizable with these diene monomers include unsaturated nitriles such as acrylonitrile and methacrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylate. ) Unsaturated carboxylic acid alkyl esters such as propyl acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyanoethyl (meth) acrylate, and monoethyl maleate; Unsaturated carboxylic acid alkoxy esters such as 2-methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate and butoxyethyl (meth) acrylate, styrene,
Aromatic vinyl compounds such as vinyltoluene, α-methylstyrene and vinylnaphthalene; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl ether compounds such as methyl vinyl ether and ethyl vinyl ether;
Α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, etc., and α, β-unsaturated carboxylic acid amides such as acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, isobutylene, ethylene, propylene, etc. And other various monomers capable of radical polymerization.

There is no particular limitation on the polymerization temperature in the present invention,
It is appropriately set depending on the type of the monomer and the type of the polymerization initiator for obtaining the desired polymer, but preferably 40 to 15
0 ° C.

There is no particular limitation on the polymerization conversion rate, but in many cases, the polymer is obtained in a state of being dissolved in the remaining monomers. Is more preferable, and more preferably 30% or less. When the polymerization conversion rate exceeds 50%, not only is it difficult to take out the polymer, but also the obtained polymer becomes three-dimensional, so that it can be used for dissolving polymers such as adhesives and sealants. Difficult to apply.

The diene polymer obtained by the production method of the present invention can be used as it is for a conventional diene polymer. Specific examples include dissolving a polymer and mixing it with a resin to use as an adhesive, kneading the polymer with a resin and using it as an impact resistance imparting agent, or using a polymer as a filler It can be used as a vulcanized rubber composition by molding and vulcanizing according to the conventional method by blending with a stabilizer, etc., and gives resins and rubbers excellent properties in terms of mechanical strength, low corrosion resistance, water resistance, etc. Can be given.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples as long as the gist of the present invention is not exceeded.

In the examples, “parts” and “%” are based on weight unless otherwise specified.

Example 1 The following materials were charged using a high-pressure autoclave having a stirrer replaced with nitrogen gas.

Acrylonitrile 35 parts Butadiene 65 parts Tetraphenylsuccinic acid dinitrile 0.192 parts (5.0 × 10 ^-4 mol) The polymerization initiator tetraphenylsuccinic acid dinitrile was synthesized according to the method of Wittig et al. (Chem. Ber., 65, 7).
60 (1932)).

The polymerization reaction was carried out while maintaining the temperature in the reactor at 90 ° C. with stirring.The heating was stopped for 10 hours, and after cooling to room temperature, the contents were poured into methanol in which hydroquinone was dissolved, and the polymerization was continued. The coalescence was allowed to settle. After washing twice with methanol, drying was performed under reduced pressure to obtain a copolymer.

The obtained copolymer was evaluated for polymerization conversion, composition, number average molecular weight, electrical corrosion resistance and impact resistance by the following methods.

The polymerization conversion was calculated from the amount of the obtained copolymer and the amount of the charged monomers. The composition of the copolymer was analyzed by elemental analysis. The molecular weight of the copolymer was obtained as the number average molecular weight in terms of polystyrene by GPC (gel permeation chromatography).

Electrocorrosion was evaluated according to the following method. Novolak resin (trade name: Tamanol 758) was added to 10 parts of the obtained copolymer.
10 parts of Arakawa Chemical Industry Co., Ltd.) was added, and 80 parts of methyl ethyl ketone was dissolved to obtain an adhesive. Next, using a test board in which a 200 μm circuit width comb-shaped parallel pattern made of copper was drawn on a glass epoxy board by a conventional method, the adhesive was applied to a thickness of about 20 μm on this test board, and dried. Was. Thereafter, the substrate is heated at a temperature of 80 ° C. with an applied voltage of 50 V.
The sample was placed in a thermo-hygrostat kept at 85% humidity, and after 24 hours, the presence or absence of a corroded portion was observed with a magnifying glass.

 The impact resistance was evaluated by the following method.

Cresol novolak type epoxy resin 100 parts (trade name Sumi Epoxy ESCN 220L manufactured by Sumitomo Chemical Co., Ltd.) Novolak resin 50 parts (trade name Tamanol 758 Arakawa Chemical Industry Co., Ltd.) Curing agent (2-methylimidazole) 1 part Polymer 10 parts These were kneaded at 80 ° C. using a closed mixer,
Press molding was performed at 160 ° C., and the obtained molded plate was subjected to milling processing to prepare an impact resistance test piece.

The impact resistance test was carried out using an Izod impact tester at room temperature using a test piece without a notch.

 Table 1 shows the measurement results.

Example 2 The same polymerization as in Example 1 was carried out except that the polymerization initiator in Example 1 was changed to 0.181 parts (5.0 × 10 ⁻⁴ mol) of 2,2,3,3-tetraphenylbutane. A coalescence was obtained. This copolymer was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 3 The amount of the polymerization initiator of Example 1 was 0.096 parts (2.5 × 10 ^-4 mol)
Polymerization was carried out in the same manner as in Example 1 except for that described above, to obtain a copolymer. This copolymer was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 4 A copolymer was obtained in the same manner as in Example 1 except that the polymerization temperature was changed to 95 ° C. and the reaction time was changed to 5 hours. This copolymer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5 The charged monomers were butadiene (63 parts) and acrylonitrile (30).
Parts, and 7 parts of methacrylic acid, except that a polymerization reaction was carried out in the same manner as in Example 1 to obtain a copolymer. This copolymer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6 The charged monomers were 70 parts of butadiene and ethyl acrylate.
A polymerization reaction was carried out in the same manner as in Example 1 except that the amount was changed to 30 parts, to obtain a copolymer. This copolymer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 A copolymer was obtained in the same manner as in Example 1 except that the polymerization initiator in Example 1 was changed to 0.121 parts (5.0 × 10 ⁻⁴ mol) of benzoyl peroxide. This copolymer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 The polymerization initiator of Example 2 was replaced with a difunctional initiator, 1,1-
Same as Example 2 except that 0.151 parts (5.0 × 10 ⁻⁴ mol) of di-t-butylperoxy-3,3,5-trimethylcyclohexane (trade name: Trigonox 29B, manufactured by Kayaku Nuuri Co., Ltd.) was used. To obtain a copolymer. This copolymer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7 The polymerization initiator was diethyl tetraphenylsuccinate 0.239.
A copolymer was obtained by performing the same polymerization reaction as in Example 1 except that the amount was changed to 0.5 × 10 ⁻⁴ mol. This polymer was evaluated in the same manner as in Example 1.

Comparative Example 3 Example 1 was obtained using a commercially available NBR (trade name: JSR N230S, manufactured by Nippon Synthetic Rubber Co., Ltd.) manufactured according to a usual emulsion polymerization recipe.
The same evaluation was performed.

Example 8 A polymer was obtained by performing the same reaction as in Example 1 except that the charged monomer was only butadiene. This polymer was evaluated in the same manner as in Example 1. The results are shown in Table 1.

From the results in Table 1, when Examples 1 to 7 are compared with Comparative Examples 1 and 2, the method for producing a diene polymer according to the present invention is as follows.
Compared to a polymer obtained by bulk polymerization using a conventional polymerization initiator, a higher molecular weight can be obtained.For example, when a blend composition with a thermosetting resin is obtained, the effect of improving mechanical strength is improved. It turns out that it is better.

Further, as compared with Comparative Example 3 by emulsion polymerization which has been conventionally used as a method for obtaining a high molecular weight diene polymer, the copolymer obtained by the production method of the present invention is:
Compared with the polymer obtained by the emulsion polymerization formulation, the polymer is less corrosive since the molecular weight is not reduced and the impurities are small and the purity is high.

As described above, it can be seen that the polymer obtained by the method for producing a diene-based polymer of the present invention has no corrosive property and is excellent in mechanical strength as compared with the polymer produced by the conventional production method.

[Effects of the Invention] According to the method for producing a diene polymer according to the present invention, the obtained polymer has excellent corrosion resistance and mechanical strength, and various fillers, stabilizers, and vulcanizing agents are added to the polymer. It can be blended and used as a vulcanized rubber composition for various industrial products such as hoses, packings, belts, sealing materials, and automotive products.

Further, the polymer obtained by the present invention has a particularly excellent electric corrosion resistance by being blended with a thermosetting resin such as an epoxy resin and a phenol resin.
It is suitable as a material for electric / electronic parts such as adhesives for printed boards, sealing materials, conductive paints, conductive adhesives, casting materials, and the like. Similarly, when the polymer obtained according to the present invention is blended with a thermoplastic resin such as polyamide, polyester, polyphenylene ether, polyphenylene sulfide, polypropylene, or polyethylene, it has excellent mechanical strength and electrical corrosion resistance. Also, blends with these thermoplastic resins are suitable as materials for electric / electronic parts.

As described above, the production method of the present invention is extremely useful for producing a diene-based polymer having high purity, high molecular weight and good mechanical strength.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-48-97985 (JP, A) JP-A-53-56283 (JP, A) JP-A-55-151006 (JP, A) 14522 (JP, B1) Japanese Patent Publication No. 43-1604 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08F 4/00 C08F 36/02-36/20

Claims (1)

(57) [Claims] 1. A bulk polymerization of a diene monomer or a diene monomer and an ethylenically unsaturated monomer in the presence of a polymerization initiator represented by the following general formula (I). A method for producing a diene polymer. General formula (I) In the formula, R ₁ and R ₂ are the same or different and represent a hydrogen, an alkyl group, a phenyl group, an aralkyl group, a cyano group, a phenoxy group, a hydroxy or alkoxycarbonyl group or a derivative thereof, and R _{3 to} R ₆ are the same or different. Differently, it represents a hydrogen, an alkyl group, a hydroxyl group, an alkoxy group, a carboxylic acid group, an amino group or a derivative thereof. However, the general formula (I) excludes the case where both R ₁ and R ₂ are phenyl groups and R _{3 to} R ₆ are all hydrogen.