JPH075647B2 - Method for producing hydroxyl group-containing liquid diene polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a hydroxyl group-containing liquid diene polymer, and more specifically to efficiently produce a liquid diene polymer having a high average number of hydroxyl groups per molecule. On how to do.

[Problems to be Solved by Prior Art and Invention]

As a method for producing a hydroxyl group-containing liquid diene polymer, a method of polymerizing a diene monomer such as butadiene in the presence of hydrogen peroxide is known. However, the average number of hydroxyl groups per polymer molecule obtained by this production method is
It was about 1.5 to 2.5, which was relatively low. However, when a cured product is produced by reacting a hydroxyl group-containing liquid diene polymer with, for example, a polyisocyanate compound,
In order to obtain a cured product excellent in strength and extensibility, it is required to use a diene polymer having a high average number of hydroxyl groups. Therefore, the above method was not suitable for this purpose. Therefore, in order to produce a diene-based polymer having a high average number of hydroxyl groups, conventionally, the diene-based monomer is first polymerized in the presence of hydrogen peroxide in the first step, and then obtained in the first step in the second step. A method of coupling a polymer with a catalyst has been adopted. However, this method is a manufacturing method consisting of two steps and cannot be said to be necessarily efficient in practice.

[Means for solving problems]

The present inventors have conducted earnest studies to solve the above problems and develop a method for efficiently producing a liquid diene polymer having a high average number of hydroxyl groups in a single step. As a result, they have found that the above object can be achieved by polymerizing a diene monomer in the presence of a specific azo compound.

That is, the present invention, when performing the polymerization of the diene monomer, 2,2'-based on 100 parts by weight of the diene monomer
Azobis {2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide} and / or
2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide} was polymerized in the presence of 0.1 to 100 parts by weight, and the number average molecular weight was 500. The present invention provides a method for producing a hydroxyl group-containing liquid diene polymer, which comprises obtaining a hydroxyl group-containing liquid diene polymer having an average number of hydroxyl groups per molecule of 2.8 to 12.0.

As the diene-based monomer which is the raw material of the present invention, diolefins having 4 to 12 carbon atoms are usually used. For example, butadiene, isoprene and chloroprene are suitable.
Further, the starting diene-based monomer may have an active hydrogen group such as a hydroxyl group, an amino group, a mercapto group and a carboxyl group.

In the present invention, the above-mentioned raw material diene-based monomer is polymerized in the presence of the following specific azo compound, that is, an azo compound having three or more hydroxyl groups.

In the present invention, this azo compound acts as a polymerization initiator. That is, the radicals generated by the cleavage of the azo compound initiate the polymerization. The azo compound used here has the following formula 2,2'-azobis {2-methyl-N- [1,1 represented by
-Bis (hydroxymethyl) ethyl] propionamide} or the following formula 2,2'-azobis {2-methyl-N- [1,1 represented by
-Bis (hydroxymethyl) -2-hydroxyethyl] propionamide} and the like and mixtures thereof. The amount of the azo compound used is usually 0.1 to 100 parts by weight, preferably 0.5 to 50 parts by weight, based on 100 parts by weight of the diene monomer. If the amount of the azo compound is less than 0.1 part by weight, the polymerization will be extremely slow, while if it exceeds 100 parts by weight, the polymerization rate will be too fast and the control thereof will be difficult.

The reaction conditions of the present invention are not particularly limited and may be appropriately determined depending on the types of reaction raw materials and azo compounds, the amount used, and the like. Usually, the reaction temperature is 0 to 200 ° C, preferably 20 to 150 ° C, the reaction pressure is 0 to 200 kg / cm ² G, preferably 0.5 to 50 kg / cm ² G, and the reaction time is 0.1 to 100 hours, preferably 0.5 to 50 hours. Is. In carrying out the method of the present invention, a solvent may be used if necessary. When a solvent is used, aliphatic saturated hydrocarbon, aromatic saturated hydrocarbon, alcohols, polar aprotic solvent (dimethylformamide, dimethylsulfoxide, etc.), water and the like can be used as the solvent.

〔The invention's effect〕

The hydroxyl group-containing liquid diene polymer obtained as described above has a number average molecular weight of 500 to 50,000, an average number of hydroxyl groups per molecule of 2.8 to 12.0, and a hydroxyl group content of 0.05 to 20 m.
It is about eq / g. The polyurethane cured product obtained by reacting the hydroxyl group-containing liquid diene polymer thus obtained with a polyisocyanate compound is extremely excellent in mechanical strength, extensibility and the like.

Thus, according to the method of the present invention, a hydroxyl group-containing liquid diene polymer having a high average number of hydroxyl groups and effective as a polyurethane raw material or the like can be efficiently produced in one step.

〔Example〕

 Next, the present invention will be described in detail with reference to Examples.

Examples 1 to 5 A stainless pressure vessel equipped with a stirrer was charged with a predetermined amount of each component shown in Table 1, and the temperature was raised to a predetermined temperature in 60 minutes.
Polymerization was carried out under stirring under the conditions shown in Table 1.

Then, 2 parts by weight of toluene containing 0.1 part by weight of 4-t-butylcatechol was added to terminate the polymerization. The obtained polymerization product was reprecipitated 3 times in a large excess of methanol, and then the light low boiling point component was distilled off for 2 hours under the condition of 100 ° C./2 mmHg to obtain a purified polymer. The physical properties of the obtained polymer are shown in Table 1.

Comparative Example 1 100 parts by weight of 1,3-butadiene, 8 parts by weight of 50% by weight hydrogen peroxide solution and 2- in a stainless steel pressure vessel equipped with a stirrer.
100 parts by weight of butanol was charged, the temperature was raised to 120 ° C. for 60 minutes, and then the reaction was carried out for 3 hours under stirring at a maximum pressure of 18 kg / cm ² G.

After completion of the reaction, the temperature was lowered and the pressure was released, 250 parts by weight of water was added, and the mixture was shaken using a separating funnel and left standing for 3 hours.
The upper phase (polymer phase) was separated. Furthermore, under the following conditions,
Residual monomer, solvent and light components were distilled off in two steps.

First step: 60 ° C./20 mmHg for 1 hour Second step: 90 ° C./2 mmHg for 2 hours The physical properties of the hydroxyl group-containing liquid polybutadiene thus obtained were as follows.

Number average molecular weight 2800 Average number of hydroxyl groups 2.2 Hydroxyl content 0.79meq / g Next, 100 parts by weight of the above liquid polybutadiene, 200 parts by weight of ethylene chloride and 0.2 parts by weight of boron trifluoride-dimethyl ether complex were charged into a three-necked flask equipped with a stirrer. The reaction was carried out at 0 ° C. for 3 hours in a nitrogen gas stream.

After completion of the reaction, the reaction mixture was gradually poured into 400 parts by weight of methanol while stirring, and allowed to stand for 1 hour, and then the product was separated. The product was dried under reduced pressure at 40 ° C. to obtain a polymer. The physical properties of this product were as follows.

Number average molecular weight 4500 Average number of hydroxyl groups 3.1 Hydroxyl content 0.68 meq / g

Claims (1)

[Claims] 1. When polymerizing a diene-based monomer, 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propion per 100 parts by weight of the diene-based monomer. Amide} and / or 2,
2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide} was polymerized in the presence of 0.1 to 100 parts by weight and had a number average molecular weight of 500 to 50,000. A method for producing a hydroxyl group-containing liquid diene polymer, characterized in that a hydroxyl group-containing liquid diene polymer having an average number of hydroxyl groups per molecule of 2.8 to 12.0 is obtained.