JPH059291A - Preparation of 2-pyrrolidone polymer - Google Patents

Abstract

PURPOSE:To obtain a high-molecular 2-pyrrolidone polymer by adding an amino acid in the polymerization of 2-pyrrolidone with the aid of a basic polymerization catalyst and polymerization-initiating carbon dioxide. CONSTITUTION:An amino acid of the formula (wherein n is 1-11) (e.g. gamma- aminobutyric acid) is added to the polymerization system of 2-pyrrolidone by the action of a basic polymerization catalyst (e.g. calcium hydroxide) and polymerization-initiating carbon dioxide. In this way, it is possible to obtain a high-molecular 2-pyrrolidone polymer which is useful as fibers and plastic materials. The amount of the basic polymerization catalyst may preferably be 0.03-0.2 mole per mole of the 2-pyrrolidone, while that of the carbon dioxide is preferably 0.2-0.6 mole per mole of the basic polymerization catalyst. Further, the amount of the amino acid may preferably be 0.05-0.2 mole per mole of the basic polymerization catalyst. When the above components are used in amounts outside the above ranges, the rate of polymerization is reduced and the resultant polymer has a low molecular weight unfavorably.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a 2-pyrrolidone polymer useful as a fiber or plastic material.

[0002]

2. Description of the Related Art A polymer of 2-pyrrolidone is known as nylon 4 and has attracted particular attention as a fiber material because it has characteristics similar to natural fibers such as cotton and silk. However, the 2-pyrrolidone polymer has an extremely poor thermal stability at high temperatures, and has a drawback that it is difficult to produce a fiber by a melt spinning method which is an economical production method of a fiber material.
As a result of many studies aimed at improving this drawback, 2-
It was found that the higher the molecular weight of the pyrrolidone polymer, the better the thermal stability, and there are many proposals for a method of producing a high molecular weight 2-pyrrolidone polymer.

For example, Japanese Patent Publication No. 39-19571 discloses a method of polymerizing distilled 2-pyrrolidone by the action of a basic polymerization catalyst and a known polymerization initiator after treatment with phosphorus pentoxide or the like. Although a 2-pyrrolidone polymer having a slightly high molecular weight can be obtained by this method, it is insufficient and has not been put into practical use. Further, the treatment with phosphorus pentoxide has a drawback that it is industrially complicated.

Japanese Patent Publication No. 47266/1987 discloses a method for obtaining a 2-pyrrolidone polymer by the action of a basic polymerization catalyst, carbon dioxide gas as a polymerization initiator, and other polymerization initiators added as necessary. ing. A 2-pyrrolidone polymer having a relatively high molecular weight can be obtained by this method, but it is still insufficient and has not been put into practical use.

Japanese Patent Publication No. 54-33280 discloses a method of polymerizing 2-pyrrolidone by the action of a basic polymerization catalyst, carbon dioxide gas and azetidinone. The molecular weight of the 2-pyrrolidone polymer obtained by this method is almost the same as those of the above two methods, is not so large, and has not been put into practical use.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process for making high molecular weight 2-pyrrolidone polymers.
That is, an object of the present invention is to provide an amino acid represented by the chemical formula (1) when 2-pyrrolidone is polymerized by the action of a basic polymerization catalyst and a polymerization initiator carbon dioxide, wherein HOOC (CH ₂ ) nNH ₂ (where n is 1-11
It can be achieved by making it exist.

The amino acid used in the present invention is a compound represented by the chemical formula. HOOC (CH ₂ ) nNH ₂ (where n is an integer of 1 to 11) Specific examples include glycine, β-alanine, γ-aminobutyric acid, ε-aminocaproic acid, aminoundecanoic acid, and aminododecanoic acid. These amino acids are effective in obtaining high molecular weight 2-pyrrolidone polymers.

The amount of amino acid used is 0.001 to 0.3 mol, and more preferably 0.
It is 005 to 0.2 mol. When the amount used is outside the above range, the molecular weight becomes low, which is not preferable.

As the basic polymerization catalyst used in the present invention, compounds generally used in the anionic polymerization method of lactams can be used. Alkali metals such as sodium, potassium and lithium; alkali metal hydroxides and hydrides, Alcoholates, oxides and salts such as potassium hydroxide, sodium hydride, potassium methylate, sodium methylate, sodium pyrrolidone, potassium pyrrolidone;
Basic organometallic compounds such as lithium alkyl, potassium alkyl, sodium alkyl, aluminum alkyl; alkali metal aryls such as sodium phenyl and sodium naphthalene; Grignard reagents such as butyl magnesium bromide and quaternary compounds represented by the chemical formula (1). There are bases.

[Chemical 1] (Wherein R ₁ , R ₂ and R ₃ are lower alkyl,
R ₄ is an alkyl group, an aryl group or an aralkyl group. )

Of these, potassium hydroxide, potassium methylate, sodium methylate, sodium pyrrolidone and potassium pyrrolidone are particularly preferable. When potassium hydroxide, potassium methylate, sodium methylate, etc. are used, it is preferable to use them after reacting 2-pyrrolidone with these compounds prior to polymerization to remove by-produced water and alcohols. ..

The amount of the basic polymerization catalyst used in the present invention is 2-
0.005-0.3mo for 1 mol of pyrrolidone
1, preferably 0.03 to 0.2 mol. If the amount used is less than the above lower limit or more than the above upper limit, the polymerization rate will be slow and the molecular weight of the resulting polymer will be low, such being undesirable.

The carbon dioxide gas as the polymerization initiator used in the present invention is preferably highly pure, but industrially available ones can be used as long as they do not particularly inhibit the polymerization. The amount of carbon dioxide gas used is 0.1 to 0.
It is 9 mol, preferably 0.2 to 0.6 mol. When the amount of carbon dioxide used is outside the above range, the polymerization rate is slow and the molecular weight of the obtained polymer is low, which is not preferable.

Although it is preferable to use carbon dioxide gas alone as the polymerization initiator, other polymerization initiators can be used together with carbon dioxide gas in the present invention. Other polymerization initiators that can be used together with carbon dioxide include acyl compounds of lactams such as acerpyrrolidone and acetylcaprolactam, acyl compounds such as adipoylbiscaprolactam, acid anhydrides such as acetic anhydride and benzene anhydride, and toluene diisocyanate. Organic isocyanates, carbamide compounds such as 1,6-hexamethylenebiscarbamidocaprolactam, 1- (1-pyrrolin-2-yl) -2-pyrrolidone, 1- (1-azacyclohepter-1-en-2-yl) 2-pyrrolidone, 6-caprolactam-1- (1
-Azacyclopent-1-en-2-yl) -1-aza-2-oxocyclopentane and quaternary ammonium salts such as tetramethylammonium chloride. These polymerization initiators are used in an amount smaller than the amount of carbon dioxide gas used.

Further, since 2-pyrrolidone which is usually available contains impurities such as water and raw material residues, it is preferable to use 2-pyrrolidone purified by a method such as distillation in the present invention. In particular, the influence of water on the polymerization reaction is great, and it is preferable to use 2-pyrrolidone having a water content of 0.1 wt% or less.

The high molecular weight 2-pyrrolidone polymer of the present invention is prepared by adding carbon dioxide gas and amino acid to 2-pyrrolidone containing a predetermined amount of basic polymerization catalyst, and heating the mixture at a temperature of 100 ° C. or lower, preferably 15 to 70 ° C. -Pyrrolidone can be obtained by ring-opening polymerization. A temperature of 100 ° C. or higher is not preferable because the polymerization rate becomes extremely slow. Carbon dioxide gas is added to 2-pyrrolidone containing a basic polymerization catalyst by blowing carbon dioxide gas into 2-pyrrolidone containing a basic polymerization catalyst at a temperature of 150 ° C or lower, preferably 15 to 100 ° C. it can. The amino acid may be added either before or after the carbon dioxide gas is blown, but rather preferably before the carbon dioxide gas is blown.

Further, it may be copolymerized with γ-butyrolactone, α-piperidone, ε-caprolactam, laurolactam and the like within 20 wt% of the total polymerization composition.
As the polymerization operation, a batch method, a continuous method, an intermediate method thereof or the like can be applied, and a polymerization reaction method includes a bulk polymerization method or a solvent such as tetrahydrofuran, dioxane, hexane, toluene, xylene, dimethylformamide, N-methylpyrrolidone. A suspension polymerization method, a solution polymerization method, an emulsion polymerization method, etc. using The present invention will be specifically described below with reference to examples.

Ηγ (relative viscosity), which is a measure of molecular weight used in Examples and Comparative Examples, is a value measured by the following method. ηγ (relative viscosity) 0.5 g of the dried 2-pyrrolidone polymer was completely dissolved in 100 cc of m-cresol at room temperature, and then the downflow time (unit: second) was measured at a temperature of 30 ° C. using an Ostwald viscometer. A value calculated by the following formula.

[0018]

EFFECT OF THE INVENTION When 2-pyrrolidone is polymerized by the action of a basic polymerization catalyst and a polymerization initiator carbon dioxide, the presence of the amino acid represented by the chemical formula (1) facilitates the formation of a high-molecular weight 2-pyrrolidone polymer. Can be manufactured.

Example 1 Purified substantially anhydrous 2 was added to a flask equipped with a vacuum device.
-Put 220 g (2.58 mol) of pyrrolidone,
After heating to ℃, 85% pure potassium hydroxide 15.5
2 g (0.235 mol in terms of potassium hydroxide) was added and the reaction was performed while raising the temperature, and the pressure in the flask was reduced (115
℃, about 5mmHg), distilled off a mixture of water and 2-pyrrolidone produced as a by-product 24g, potassium pyrrolidone 0.1mo
A 2-pyrrolidone solution containing 1 was made. Dry nitrogen was introduced into this system to bring it to normal pressure, and after lowering the temperature of the liquid to 25 ° C., 1.21 g of γ-aminobutyric acid (0.012 mol,
Basic polymerization catalyst potassium pyrrolidone (0.05 mol) was added to 1 mol). Then carbon dioxide 3.3g
(0.075 mol, 0.32 mol per 1 mol of basic polymerization catalyst potassium pyrrolidone) was introduced, and then polymerization was carried out at 40 ° C. for 24 hours in a nitrogen gas atmosphere. The produced polymer was pulverized, sufficiently removed with water to remove unreacted monomers, potassium, etc., and dried under reduced pressure at 70 ° C. for 24 hours, and then ηγ was measured. ηγ was 13.1.

Comparative Example 1 The procedure of Example 1 was repeated except that γ-aminobutyric acid was not used. The measurement results of ηγ are shown in Table 1.

Comparative Example 2 The amount of γ-aminobutyric acid used was 8.5 g (0.082 mo).
Example 1 was carried out in the same manner as in Example 1 except that the basic polymerization catalyst potassium pyrrolidone was replaced by 0.35 mol). The measurement results of ηγ are shown in Table 1.

Comparative Example 3 2-pyrrolidone (500 g, 5.9 mol) and phosphorus pentoxide (2)
After adding 0.9 g and heating at a temperature of 140 ° C. for 1 hour,
Using 2-pyrrolidone obtained by filtering and distilling the filtrate under reduced pressure at about 115 ° C. and about 2 mmHg.
-A procedure similar to that of Example 1 was used except that aminobutyric acid was not used. The measurement results of ηγ are shown in Table 1.

Examples 2 to 4 Table 2 shows the amounts of γ-aminobutyric acid and carbon dioxide used and the polymerization temperature.
The same method as in Example 1 was carried out except that the numerical value of was replaced by. The measurement results of ηγ are shown in Table 2.

Example 5 2-pyrrolidone (220 g) and potassium hydroxide having a purity of 85% (31.04 g, 0.47 mol in terms of potassium hydroxide)
Was added and reacted in the same manner as in Example 1, using a 2-pyrrolidone solution containing 0.2 mol of potassium pyrrolidone produced by distilling out 28 g of a mixture of water and 2-pyrrolidone as a by-product, and γ -4.31 g of ε-aminocaproic acid instead of aminobutyric acid (0.033 mol, 0.07 m per 1 mol of basic polymerization catalyst potassium pyrrolidone)
ol) It carried out by the same method as Example 1 except having used. The measurement results of ηγ are shown in Table 2.

Example 6 Purified substantially anhydrous 2 was added to a flask equipped with a vacuum device.
-Pyrrolidone (200 g, 2.35 mol) was added, and 90
95% pure sodium methylate after heating to 8 ° C
g (0.148 mol) was added and the reaction was carried out, the pressure in the flask was reduced (115 ° C., about 5 mmHg), the by-product methanol was distilled off, and sodium pyrrolidone 0.06 mo was removed.
A 2-pyrrolidone solution containing 1 was made. Dry nitrogen was introduced into this system to bring it to normal pressure, and after lowering the temperature of the liquid to 25 ° C., 2.29 g of γ-aminobutyric acid (0.022 mol,
0.15 mol) was added to 1 mol of the basic polymerization catalyst sodium pyrrolidone. Then carbon dioxide 1.3g
(0.03 mol, 0.2 mol per 1 mol of basic polymerization catalyst sodium pyrrolidone) was introduced into this solution, and then polymerization was carried out at 50 ° C. for 24 hours in a nitrogen gas atmosphere. The produced polymer was pulverized, washed sufficiently with water to remove unreacted monomers and sodium, and dried under reduced pressure at 70 ° C. for 24 hours. ηγ was 10.1.

[Table 1]

[Table 2]

Claims (1)

Claims: 1. Amino acid represented by the chemical formula when 2-pyrrolidone is polymerized by the action of a basic polymerization catalyst and a polymerization initiator carbon dioxide, wherein HOOC (CH ₂ ) nNH ₂ (where n is An integer of 1 to 11) A method for producing a high molecular weight 2-pyrrolidone polymer, characterized by being present