JPH0768346B2 - Method for producing polyamide elastomer - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a polyamide elastomer.

[0002]

2. Description of the Related Art Polyamide elastomer having polyamide 6 as a hard segment and polyalkylene oxide as a soft segment is a material widely used as an industrial material. As a method for producing this polyamide elastomer, for example, first, a dicarboxylic acid and ε-caprolactam are reacted to synthesize a polyamide oligomer having carboxyl groups at both ends, and dehydration condensation is performed between the polyamide oligomer and the polyalkylene glycol. 50-5095
No. 86, JP-A No. 54-47798, etc.) and ε
-Method for dehydration condensation of caprolactam, dicarboxylic acid and polyalkylene glycol at the same time (Industrial Chemistry Magazine)
Volume 62, No. 8, page 33 (1959), JP-A-58-210925, JP-A-62-81419, JP-A-63-278930) and the like are known.

Further, in the production of the above polyamide elastomer, a dehydration condensation catalyst is usually used to accelerate the reaction and increase the molecular weight. Examples of such a catalyst include titanium tetraalkoxide (Japanese Patent Publication No. 56-454).
19), zirconium tetraalkoxide, or hafnium tetraalkoxide (Japanese Patent Publication No. 58-114).
59), tin compounds (Japanese Patent Publication No. 63-6520).
6), antimony oxide (Japanese Patent Publication No. 63-65207), pyrophosphoric acid, triphosphoric acid, polyphosphoric acid, metaphosphoric acid and their esters (JP-A-63-278930). However, in these conventionally known catalysts, when the obtained polyamide elastomer does not have a high molecular weight, when a high molecular weight polymer is obtained, the coloring is intense, when the reaction time is long, or a large amount of the catalyst is used. In some cases, it is necessary to do so, and a satisfactory catalyst has not been found yet.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for producing a high molecular weight polyamide elastomer which has a short reaction time and can reduce the amount of catalyst, and is transparent and less colored.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems of the prior art, the inventors of the present invention have conducted extensive studies focusing on dehydration condensation catalysts used in the production of polyamide elastomers, and as a result, various Among the dehydration condensation catalysts, when phosphorous acid or a phosphorous acid ester is selected and used,
The inventors have found that the above problems can be solved completely and have completed the present invention.

That is, the present invention is (A) having 4 to 2 carbon atoms.
0 dicarboxylic acid, (B) number average molecular weight 200-200
In a method for producing a polyamide elastomer by dehydration condensation of polyalkylene glycol of No. 00 and (C) ε-caprolactam, phosphorous acid or a phosphite ester is used as a catalyst.

First, the constituent components of the present invention will be described.

Examples of the (A) dicarboxylic acid having 4 to 20 carbon atoms include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid, and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and decalindicarboxylic acid. Examples thereof include various known dicarboxylic acids such as acids, succinic acid, adipic acid, sebacic acid, dodecanedioic acid and other aliphatic dicarboxylic acids, each of which may be used alone or in combination of two or more.

As the polyalkylene glycol (B) of the present invention, various known ones can be used, and examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and block or random copolymers of ethylene oxide and propylene oxide. Can be given.

The number average molecular weight of these polyalkylene glycols is 200 to 20,000, preferably 400 to 40.
00. If it is less than 200, the obtained polyamide elastomer becomes liquid at room temperature and does not exhibit elasticity as a thermoplastic elastomer, and if it exceeds 20,000, it becomes too hard and the time required for producing the polyamide elastomer becomes long, which is not realistic.

The molar ratio of the above component (A): component (B) is usually in the range of 1: 0.95 to 1.05.
When the ratio of the component (B) is less than 0.95 or exceeds 1.05, the molecular weight does not increase.

The components (A) and (B) are soft segments introduced into the polyamide elastomer of the present invention as a polyester having a polyalkylene oxide in the main chain. The proportion of such a soft segment in the polyamide elastomer is usually 20 to 80% by weight.
The amount is preferably about 25 to 75% by weight. Two
If it is less than 0% by weight, it does not exhibit rubber elasticity at room temperature and becomes hard.
If it exceeds 0% by weight, the melting point is lowered to cause blocking, or heat resistance and mechanical strength are extremely deteriorated.

Further, (C) ε-caprolactam is introduced into the polyamide elastomer of the present invention as polyamide 6 which is a hard segment, and the proportion thereof is usually 20.
It is about 80 to 80% by weight, preferably 25 to 75% by weight. If it is less than 20% by weight, heat resistance and mechanical strength are weak, and if it exceeds 80% by weight, flexibility is deteriorated, which is not preferable. Since a portion of ε-caprolactam remains unreacted, it is preferable to use more than the desired amount introduced into the polyamide elastomer.

In the present invention, it is essential to use phosphorous acid or phosphorous acid ester as a catalyst for dehydration condensation of the above-mentioned components (A), (B) and (C).
That is, the object of the present invention was achieved for the first time by selecting phosphorous acid or phosphite ester from among various dehydration condensation catalysts, dehydration condensation catalyst other than phosphorous acid or phosphite ester Then, the object of the present invention cannot be achieved. Examples of the phosphite include triphenyl phosphite, triethyl phosphite, trialkyl phosphite and triaryl esters such as tributyl phosphite, diphenyl phosphite, diethyl phosphite, and dibutyl phosphite. Examples thereof include dialkyl and diaryl phosphites, phenyl phosphite, ethyl phosphite, butyl phosphite and other monoalkyl and monoaryl phosphites. Among these, phosphites,
Phosphorous acid triester is particularly preferable. The amount of phosphite or phosphite used is 0.01 based on 100 parts by weight of the total of the components (A), (B) and (C).
~ 5 parts by weight, preferably 0.01 to 1 part by weight. If it is less than 0.01 parts by weight, the molecular weight of the elastomer does not increase, and if it exceeds 5 parts by weight, gelation occurs or coloring becomes severe, which is not preferable.

The method for producing the polyamide elastomer of the present invention is not particularly limited, and either the above-mentioned two-step reaction or simultaneous reaction may be used. When the two-step reaction is adopted, first, ε-caprolactam and dicarboxylic acid are charged, and usually about 150 to 300 ° C., preferably 200
After reacting at a reaction temperature of 280 ° C. for about 2 to 24 hours to synthesize a polyamide oligomer having carboxyl groups at both ends, the above predetermined amount of polyalkylene glycol and a catalyst are added to dicarboxylic acid at the same temperature. To react further. When the simultaneous reaction is adopted, a predetermined amount of ε-caprolactam, dicarboxylic acid, polyalkylene glycol and catalyst are charged in a batch, and usually 150-35.
At a reaction temperature of about 0 ° C, preferably 200 to 300 ° C,
Usually, the reaction is performed for about 2 to 24 hours. In addition, in any of the methods, a part of ε-caprolactam remains in the reaction system unreacted, and thus is removed under reduced pressure in a heated state after completion of the reaction. Further, when the polymerization degree of the obtained polyamide elastomer is to be increased, unreacted ε-
After removing caprolactam, 150-350 under reduced pressure
It is also possible to carry out post-polymerization at ° C.

During the reaction, an additive such as an antioxidant can be added in order to enhance the thermal stability of the obtained elastomer. Also, such additives may be added after the elastomer is manufactured. Examples of such additives include N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydroxycinnamide), pentaerythrityl-tetrakis [3- (3,5
-Di-t-butyl-4-hydroxybutyl) propionate], 1,6-hexanediol-bis [3- (3,3
5-di-t-butyl-4-hydroxybutyl) propionate], hindered phenols, amines such as N, N′-diphenyl-p-phenylenediamine, sulfur compounds such as dilaurylthiodipropionate, alkali Examples thereof include earth metal compounds and iodine compounds.

[0017]

According to the production method of the present invention, it is possible to produce a high molecular weight polyamide elastomer which is short in reaction time, can reduce the amount of catalyst, and is transparent and has little coloring.

Example 1 ε-caprolactam 633.6 g (5.6 mol), adipic acid 58.4 g (0.4 mol), polyethylene glycol (number average molecular weight 1530) 612 g (0.4 m)
ol), 3.2 g of triphenyl phosphite and Irganox 1098 (N, N′-hexamethylenebis (3,5)
-Di-t-butyl-4-hydroxy-hydroxycinnamide), manufactured by Ciba-Geigy Co., Ltd.) (6.4 g) was charged into a 2 liter reaction vessel and kept at 250 ° C for 4 hours in a nitrogen stream.
Then, the pressure was gradually reduced to remove unreacted ε-caprolactam, and the reaction was further performed at 1 Torr. After 30 minutes, the rotation torque of the stirrer (rotation speed 200 rpm) was 10
Kg · cm was reached and a slightly yellow transparent resin was obtained. The results are shown in Table 1.

Example 2 ε-caprolactam 633.6 g (5.6 mol), adipic acid 21.9 g (0.15 mol), polyethylene glycol (number average molecular weight 4020) 603 g (0.1
5 mol), 3.2 g of triphenyl phosphite and 6.4 g of Irganox 1098 (manufactured by Ciba Geigy) were placed in a 2-liter reaction vessel and kept at 250 ° C. for 8 hours in a nitrogen stream. Then, the pressure was gradually reduced to remove unreacted ε-caprolactam, and the reaction was further performed at 1 Torr. After 30 minutes, the rotation torque of the stirrer (rotation speed 200 rp
m) reached 10 kg · cm, and a slightly yellow transparent resin was obtained. The results are shown in Table 1.

Example 3 ε-caprolactam 486.6 g (4.3 mol), adipic acid 219.2 g (1.5 mol), polyethylene glycol (number average molecular weight 398) 597 g (1.5 m)
)), 3.2 g of triphenyl phosphite and 6.4 g of Irganox 1098 (manufactured by Ciba Geigy) were placed in a 2-liter reaction vessel and kept warm at 250 ° C. for 2 hours in a nitrogen stream. Then, the pressure was gradually reduced to remove unreacted ε-caprolactam, and the reaction was further performed at 1 Torr. 40
After a minute, the rotation torque of the stirrer (rotation speed 200 rpm) is 1
It reached 0 Kg · cm, and a slightly yellow transparent resin was obtained. The results are shown in Table 1.

Example 4 ε-caprolactam 633.6 g (5.6 mol), adipic acid 58.4 g (0.4 mol), polyethylene glycol (number average molecular weight 1530) 459 g (0.3 m)
ol), tetramethylene glycol (number average molecular weight 14
88) 148.8 g (0.1 mol), triphenyl phosphite 3.2 g and Irganox 1098 (manufactured by Ciba-Geigy) were placed in a 2-liter reaction vessel and kept at 250 ° C. for 4 hours in a nitrogen stream. Then, the pressure is gradually reduced to remove unreacted ε-caprolactam, and further 1
The reaction was carried out at Torr. After 35 minutes, the rotation torque of the stirrer (rotation speed 200 rpm) reached 10 Kg · cm,
A slightly yellow transparent resin was obtained. The results are shown in Table 1.

Example 5 ε-caprolactam 633.6 g (5.6 mol), adipic acid 58.4 g (0.4 mol), tetramethylene glycol (number average molecular weight 1488) 595.2 g
(0.4 mol), triphenyl phosphite 3.2 g and Irganox 1098 (manufactured by Ciba Geigy) 6.4 g
Was charged in a 2-liter reaction vessel and kept at 250 ° C. for 4 hours in a nitrogen stream. After that, the pressure is gradually reduced and unreacted ε-
Caprolactam was removed, and the reaction was performed at 1 Torr. After 40 minutes, the rotation torque of the stirrer (rotation speed 200
rpm) reached 10 Kg · cm, and a slightly yellow transparent resin was obtained. The results are shown in Table 1.

[0023]

[Table 1]

Examples 6 to 9 The reaction was carried out in the same manner as in Example 1 except that the catalyst shown in Table 2 was used instead of the triphenyl phosphite of Example 1, and the results shown in Table 2 were obtained. It was

[0025]

[Table 2]

Comparative Examples 1 to 3 Reactions were carried out in the same manner as in Example 1 except that the catalyst shown in Table 3 was used instead of the triphenyl phosphite of Example 1, and the results shown in Table 3 were obtained. It was

[0027]

[Table 3]

Claims (2)

[Claims] 1. A dicarboxylic acid having 4 to 20 carbon atoms,
In the method for producing a polyamide elastomer by dehydrating and condensing (B) a polyalkylene glycol having a number average molecular weight of 200 to 20,000 and (C) ε-caprolactam, phosphorous acid or a phosphite ester is used as a catalyst. A method for producing a polyamide elastomer. 2. A phosphorous acid or a phosphorous acid ester is used in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the total weight of the components (A), (B) and (C). The manufacturing method according to claim 1.