JP2890758B2 - Method for producing macromonomer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Purpose of the invention [Industrial field of application] The present invention provides a polymer part with a hydroxyl group or an epoxy group, which is suitable as a raw material for a graft polymer, which is a kind of functional polymer. The present invention relates to a method for producing a macromonomer having the same.

[Conventional technology and its problems]

In recent years, macromonomers have been copolymerized with other monomers,
There have been many studies to synthesize a graft polymer. The graft polymer obtained by such a method is
It has the advantage that the structure is relatively well controlled.

The macromonomer is a high molecular weight monomer having a polymerizable group at one end of the molecule and is synthesized by various methods.

For example, a method of forming a skeleton of a macromonomer by radical polymerization is industrially most advantageous and excellent in that many kinds of macromonomers can be synthesized. An outline of this method will be described below. Radical polymerization of a vinyl monomer in the presence of a chain transfer agent to obtain a vinyl polymer having a terminal carboxyl group (hereinafter also referred to as a prepolymer), and then reacting the prepolymer with glycidyl (meth)acrylate As a result, a macromonomer having a (meth)acryloyl group at the terminal is synthesized.

However, in the above synthesis method, 2-hydroxyethyl (meth)acrylate or glycidyl (meth)acrylate is used as the vinyl monomer to synthesize a macromonomer having a polymer skeleton containing these monomer units. However, there is a problem that a side reaction mainly occurs at the stage of reacting the prepolymer with glycidyl (meth)acrylate, and the macromonomer is practically not obtained, and the glycidyl (meth)acrylate is added to the prepolymer. The present situation is that macromonomerization reactions other than the above-mentioned conventional methods are required.

Regarding a water-soluble macromonomer composed of monomer units such as vinylpyrrolidone and acrylamide, a water-soluble prepolymer having a terminal carboxyl group is synthesized by a radical polymerization method, and the carboxyl group is neutralized with sodium hydroxide to produce a carboxylic acid. A macromonomerization reaction in which this prepolymer is reacted with chloromethylstyrene at a mild reaction temperature after conversion to an alkali metal salt has recently been proposed (Akashi Man et al., Ang. Makromol. Chem., 132 , 81,1
985).

However, even in the above method, the reaction of chloromethylstyrene with the prepolymer takes time, and the applicability of this method to a hydrophobic prepolymer is not known.

(B) Configuration of the Invention [Means for Solving the Problems] The present inventors have completed the present invention as a result of intensive studies to solve the above problems.

That is, the present invention provides a hydrophobic polymer molecular chain composed of a 2-hydroxyethyl (meth)acrylate monomer unit and/or a glycidyl (meth)acrylate monomer unit, and another vinyl monomer unit. At one end of the
(Where M is an alkali metal) and has a number average molecular weight of 1000 to
A vinyl polymer which is 30,000 and 0.8 to 3.
Characteristically, the polymer and chloromethylstyrene are reacted at a temperature of 70 to 150° C. in the presence of a catalyst while blowing an oxygen-containing gas into an organic solvent solution in which 0 times mol of chloromethylstyrene is dissolved. And a method for producing a macromonomer.

Hereinafter, the present invention will be described in more detail.

[Production of vinyl polymer having group-COOM at one end of molecular chain]

The polymer converted into a macromonomer in the present invention comprises a 2-hydroxyethyl (meth)acrylate monomer unit and/or a glycidyl (meth)acrylate monomer unit, and another vinyl monomer unit. It is a vinyl polymer having a group -COOM (wherein M is an alkali metal) at one end of a hydrophobic polymer molecular chain and having a number average molecular weight of 1,000 to 30,000. The vinyl polymer is mercaptoacetic acid or In the presence of a radical chain transfer agent having a carboxyl group such as mercaptopropionic acid, radical polymerization of vinyl monomers as exemplified below to synthesize a polymer having a carboxyl group at one end, Obtained by neutralizing the groups.

The vinyl monomer used in the production of the vinyl polymer is 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate and other vinyl monomers, and as the other vinyl monomer, Styrene, styrene substitution product, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, (meth)
2-Ethylhexyl acrylate, (meth)acrylonitrile, (meth)acrylamide, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, phenylmaleimide and the like can be mentioned, and these can be used alone or in combination.

In the present invention, according to the conventional technique of adding glycidyl (meth)acrylate to a prepolymer to obtain a macromonomer, a high-purity macromonomer cannot be obtained. It allows the use of 2-hydroxyethyl (meth)acrylate or glycidyl (meth)acrylate, which were considered suitable.

The number average molecular weight of the vinyl polymer is determined by appropriately selecting the amounts of the chain transfer agent, the polymerization initiator and the like to be added to the polymerization system, and more preferably 2000 to 20000. The number average molecular weight in the present invention is a polystyrene equivalent number average molecular weight measured by gel permeation chromatography (hereinafter referred to as GPC).

Next, a polymerization method for obtaining a vinyl polymer having a carboxyl group at one end will be described.

As the polymerization method, any of a solution polymerization method, a bulk polymerization method and a suspension polymerization method can be used, but a solution polymerization method is preferable.

As the organic solvent used in the solution polymerization method, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethanol, isopropyl alcohol, methyl cellosolve, ethyl acetate, butyl acetate, hexane, cyclohexane and the like are preferably used, and the monomer in the solution. The concentration of 10 to 80% by weight is preferable, and more preferably 20% by weight.
~ 70% by weight.

As the polymerization initiator, an azo compound is preferable, and specifically, 2,2-azobisisobutyronitrile (hereinafter referred to as AIBN
Abbreviated), 4,4-azobis-4-cyanovaleric acid, 1-azobis-1-cyclohexanecarbonitrile and the like.

The vinyl polymer having a carboxyl group at one end obtained by the above-mentioned method is subjected to the following operations to obtain an alkali hydroxide such as lithium hydroxide, sodium hydroxide and potassium hydroxide or sodium carbonate or potassium carbonate. After being neutralized by the addition of the alkali metal carbonate of the above, it is subjected to a macromonomerization reaction.

When an alkali hydroxide is used as the neutralizing agent, an approximately theoretical amount of the alkali hydroxide is added as an aqueous solution to the organic solvent solution of the polymer, and the thus obtained solution containing about 1% by weight of water is emulsified, It can be neutralized by stirring vigorously at room temperature for 5 to 60 minutes.

On the other hand, when an alkali metal carbonate is used as the neutralizing agent, the powdery alkali metal carbonate can be added directly to the organic solvent solution of the polymer and neutralized by stirring at a temperature of 50 to 110°C. In this case, the preferred amount of alkali metal carbonate used is 1 to the carboxyl group of the polymer.
It is 5 times equivalent.

The amount of carboxyl groups in the vinyl polymer is
It can be measured by a neutralization titration method using bromothymol blue as an indicator, and the required amount of alkali is appropriately determined based on the measured value.

The solution of the vinyl polymer having a group -COOM (M is an alkali metal) at the terminal obtained by the above method contains a small amount of water in addition to the by-produced alkali chloride, or powdered alkali metal carbonate. Although salts are contained in a dispersed state, they can be directly used for the macromonomerization reaction without separation and purification.

[Manufacture of macromonomer]

In the present invention, chloromethylstyrene is added to an organic solvent solution in which a vinyl polymer having a group -COOM at a terminal is dissolved at a ratio of 0.8 to 3.0 mol per 1 mol of the polymer,
While blowing oxygen-containing gas, in the presence of a catalyst, the temperature 70
By reacting the group —COOM with the chloromethyl group at ˜150° C., a macromonomer having a styryl group introduced at the end of the polymer via a methylene group is synthesized.

The organic solvent used as the reaction medium is the organic solvent used in the solution polymerization to obtain the vinyl polymer which is one of the reaction components. That is, an organic solvent solution of a vinyl polymer obtained by solution polymerization can be used for the above reaction as it is or after appropriately diluting it.

The main features of the present invention are that a high temperature range of 70 to 150° C. is adopted as a reaction temperature and that an oxygen-containing gas is blown during the reaction. Thus, it was possible to easily obtain a high-purity macromonomer.

When the reaction temperature is at 70° C., it takes a long time to complete the reaction, while when it exceeds 150° C., chloromethylstyrene is polymerized, and the yield of the styryl group introduction reaction is poor.

Further, in the present invention, in order to prevent radical polymerization of chloromethylstyrene and the generated macromonomer, it is necessary to blow an oxygen-containing gas into the system during the reaction, and the preferable oxygen concentration in the oxygen-containing gas used is 2 to 25%, and usually air or a mixed gas of air and nitrogen is suitable.

The amount of the oxygen-containing gas blown into the reaction system is usually 5 to 200 ml/min, and more preferably 20 to 150 ml/min, per 1 kg of the reaction solution.

When the amount of chloromethylstyrene used is less than 0.8 mol per 1 mol of the polymer, the terminal polymerizable groups of the macromonomer produced are insufficient, while when it exceeds 3 mol, unreacted chloromethyl in the macromonomer is present. It is unsuitable because a large amount of styrene remains. A more preferable reaction ratio is
The ratio of chloromethylstyrene is 1.0 to 3.0 mol per mol of the polymer.

The catalyst is preferably a quaternary phosphonium salt or quaternary ammonium salt known as a phase transfer catalyst, specifically, tetrabutylphosphonium bromide, triphenylbutylphosphonium bromide, triethylbenzylammonium chloride, trimethylcetylammonium bromide, tetrabutylammonium. Examples include bromide and trimethylbenzylammonium chloride.

The preferred amount of the catalyst used is 0.02 to 100 parts by weight of the total amount of the polymer to be reacted and chloromethylstyrene.
2.0 parts by weight. If the addition amount is less than 0.02 parts by weight, the reaction rate is slow, and if it exceeds 2.0 parts by weight, the amount of catalyst remaining in the macromonomer is too large and the performance of the macromonomer is poor.

The preferred concentration of the total amount of the polymer and chloromethylstyrene in the reaction solution is 10 to 80% by weight, 20
˜70% by weight is more preferred. If it is less than 10% by weight, the yield of macromonomer is low, and if it exceeds 80% by weight, the solution viscosity is too high and stirring becomes difficult.

A known polymerization inhibitor may be added to the reaction system in order to prevent radical polymerization during the macromonomerization reaction.

The alkali chloride contained in the macromonomer solution can be easily removed by filtration or the like, if necessary.

The macromonomer produced by the above method can be used as it is in a solution or after removing the solvent for various uses. For example, it can be copolymerized with other radically polymerizable monomers to produce a graft polymer, which is a prize as an adhesive, a paint, a coating material, a molding material, an elastomer, a medical material and an electronic material. Used.

[Examples and Comparative Examples]

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The percentages and parts described in each example are all based on weight.

Example 1 A 500 ml glass flask equipped with a stirrer, a reflux condenser, a dropping funnel, a gas introduction tube and a thermometer was charged with 30 parts of 2-hydroxyethyl methacrylate, 1.8 parts of mercaptopropionic acid and 30 parts of methyl cellosolve, while 2-hydroxyethyl methacrylate is used for the dropping funnel.
70 parts, 27.5 parts of methyl cellosolve and 0.1 part of AIBN were charged.

While blowing nitrogen through the gas inlet tube,
After heating to 0° C., the liquid in the dropping funnel was added dropwise over 2 hours. Then 42.5 parts of methyl cellosolve and AIBN
0.85 parts was added from a dropping funnel over 3 hours. The temperature was maintained at 90° C. for another 2 hours to synthesize poly(2-hydroxyethyl methacrylate) having a carboxyl group at the terminal.

Then, 1.42 parts of a 48% sodium hydroxide aqueous solution was added to the obtained polymer solution, and the mixture was stirred for 30 minutes. Hydroquinone monoethyl ether 0.04 parts, p-chloromethylstyrene 2.85 parts (1.
(1 equivalent) and tetrabutylphosphonium bromide (0.5 part) were charged and reacted at 90° C. for 8 hours while blowing air at 20 ml/min to synthesize a macromonomer.

0.8 part of the above macromonomer solution was put into a test tube together with 3.6 parts of styrene, 5.6 parts of dimethylformamide and 0.04 part of AIBN, and kept at 70° C. for 15 hours for polymerization.

GPC measurement was performed on the obtained reaction liquid, and no shoulder of the residual macromonomer was observed. The reaction solution was added to a large excess of methanol, reprecipitated, and the result of measuring the hydroxyl value of the purified and separated graft polymer was 0.424 meq./g, and the polyhydroxyethyl methacrylate chain was converted to polystyrene. It turned out that it was certainly grafted.

Comparative Example 1 In the same manner as in Example 1, poly(2-hydroxyethyl methacrylate) having a carboxyl group at the terminal was synthesized.

Then, in the obtained polymer solution, hydroquinone monomethyl ether 0.04 part, glycidyl methacrylate
2.65 parts (1.1 times mol relative to the carboxyl group) and 0.5 part of tetrabutylphosphonium bromide were charged and heated at 90° C. while blowing the same amount of air as in Example 1. 8
When heated for an hour, the reaction rate was 8%. 30 more
Even after heating for an hour, the reaction rate remained at 24%, and no macromonomer usable as a raw material for the graft copolymer was obtained.

(C) Effect of the Invention According to the present invention, (meth)acrylic acid 2-which was practically impossible to synthesize by a conventional macromonomerization reaction utilizing a reaction between a carboxyl group and glycidyl (meth)acrylate It becomes possible to synthesize a macromonomer composed of a polymer containing a monomer unit such as hydroxyethyl or glycidyl (meth)acrylate, and not only the above-mentioned monomer but also a polymer composed of various other monomer units. The macromonomer having a united skeleton can be produced in high purity in a short time.

Claims (1)

(57) [Claims] 1. A hydrophobic polymer molecular chain comprising a 2-hydroxyethyl (meth)acrylate monomer unit and/or a glycidyl (meth)acrylate monomer unit, and another vinyl monomer unit. A vinyl polymer having a group -COOM (where M is an alkali metal) having a number average molecular weight of 1000 to 30000 at one end and 0.8 to 3.0 times mol of chloromethylstyrene with respect to the polymer are dissolved. In the organic solvent solution
While blowing the oxygen-containing gas, in the presence of the catalyst, the temperature
A method for producing a macromonomer, which comprises reacting the polymer with chloromethylstyrene at 70 to 150°C.