JPS6222829A - Production of polyamide of high degree of polymerization - Google Patents

Abstract

PURPOSE:To obtain a polyamide of a high degree of polymerization easily and rapidly, by increasing the MW of an amino group-terminated polyamide by reacting it with a bislactone compound. CONSTITUTION:An amino group-terminated polyamide is reacted by heating with at least either of the bislactones of formulas I and II to increase the MW of the polyamide. In the formulae, D is a tetravalent organic group which makes each of the ring structures five- or six-membered, R1 is H, or a monovalent organic group, R2 is a monovalent organic group, R3 is a bivalent organic group which makes each of the ring structures five- or six-membered, R4 is a bivalent organic group and all of said organic groups are those unreactive with the polyamide. The polyamide used is thermosetting preferably, thermoplastic having a m.p.<=350 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a polyamide with a high degree of polymerization, and more specifically, a method for reducing the molecular weight of the polyamide by reacting the terminal amino groups of the polyamide with a bislactone compound having a specific structure under heating. This invention relates to a method for rapidly increasing polyamide with a high degree of polymerization.

Prior art nylon 6, nylon 6.6. Polyamides, typified by nylon 6.10, are manufactured by polycondensation reactions and are melt-molded into fibers, films, plastics, etc. and used in a wide range of fields. In recent years, with the advancement of technology, the mechanical properties of these polyamides have improved, especially strong and tough.

It is desired to further improve the performance of polymers, and various studies have been conducted to increase the degree of polymerization as a means of achieving this goal. Generally, the method of increasing the degree of polymerization of polyamide is to carry out a polycondensation reaction in the molten state at high temperature and under high vacuum. In addition to difficulty in stirring due to increased viscosity, problems such as thermal decomposition and gelation also occur. Therefore, in order to suppress decomposition, etc., a method of performing a one-phase polycondensation reaction at a relatively low temperature is considered, but this method also requires a long time for the reaction and has low productivity.
・There are some drawbacks.

OBJECTS OF THE INVENTION An object of Akira Kinoshita is to provide a method for producing a polyamide with a high degree of polymerization, which eliminates such drawbacks and increases the degree of polymerization of polyamide in a short period of time.

Structure/Effect of the Invention The present inventor has conducted intensive research into a method for solving the drawbacks of the prior art and increasing the degree of polymerization of polyamide in a short time, and has found that a bislactone compound having a specific structure can be
It was discovered that #polyamide could be made to a high degree of polymerization in a short time by reacting easily and quickly with the amino group terminal under heating, and the molecular pressure was reached.

That is, the present invention provides a highly polymerized polyamide characterized in that the molecular weight of the polyamide is increased by thermally reacting a polyamide having a terminal amino group with at least one bislactone compound represented by the following formula +11 or +21. This is the manufacturing method.

The polyamide in the present invention is a thermoplastic polyamide, preferably a thermoplastic polyamide having a melting point of 350° C. or lower.

Such polyamides include amino acid (or lactam) self-condensing polyamides, dibasic acid/diamine condensation polyamides, and copolymers thereof, and specifically, nylon 4, nylon 6, nylon 7, nylon 9
゜Nylon 11. Nylon 12. Nylon 66° Nylon 69. Nylon 610. nylon 612, nylon 6
aliphatic polyamides such as 766 copolymer, nylon 6/66/6] 0 copolymer, and 7-mide-forming compounds containing an aromatic group as a copolymer component in these aliphatic polyamides, such as phenylene and naphthalene. , aromatic diamines containing aromatic groups such as biphenylene (e.g. p
- or m-) unilene diamine + 4+4'- or 3,4'-diaminodiphenyl ether, methylene dianiline, etc.), aromatic dicarboxylic acids (e.g. terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid) etc),
Examples include polymers copolymerized within the range of aromatic aminocal concave, preferably 350°C or lower.

The polyamide used in the present invention must have a terminal 7-mino group, and the concentration of the terminal amino group is determined by the amount of amino groups (-NH,
) is 20 oil amount/106 II polymer or more, and even 3
0 equivalents/10', 9 polymers 1 or more, especially 40 equivalents 11
/10'19 polymer or more is preferable. The molecular weight of the polyamide to be reacted with the bislactone compound is preferably 0.3 or more, more preferably 0.5 or more, still more preferably 0.7 or more, and 4? It is preferably 1.0 or more.

The bislactone compound used in the present invention has the above formula 111,
It is a compound represented by +21. The formula fil,
R2 in +21 is a hydrogen atom or a monovalent organic group, and the organic group includes a furkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, and a aryl group having 6 to 12 carbon atoms which may have a substituent. Preferred examples include a dichlorofurkyl group having 6 to 12 carbon atoms, which may be present. In particular, R is preferably a hydrogen atom. Further, bird is a monovalent organic group, preferably the same as the monovalent organic group of R1, particularly a 7-aryl group having 6 to 12 carbon atoms which may have substituents such as phenyl and naphthyl. A divalent organic group forming a 5-membered ring or a 6-membered ring, a fullkylene group having 2 to 6 carbon atoms, a 7-rylene group having 6 to 12 carbon atoms which may have a substituent, and a 7-rylene group having 6 to 12 carbon atoms, which may have a substituent. Preferred examples include cycloalkylene groups having 6 to 12 carbon atoms.

In particular, R8 is ethylene, trimethylene, 〇-phenylene, and 1,2-cyclohexylene.

2,3-dicyclopentylene and the like are preferred. Furthermore,
R4 is a divalent organic group, including a fullylene group having 2 to 12 carbon atoms, an arylene group having 6 to 12 carbon atoms which may have a substituent, and a arylene group having 6 to 12 carbon atoms which may have a substituent. Preferred examples include cycloalkylene groups. %KR is preferably an arylene group such as phenylene, a 5-membered ring or a 6-membered ring.
-O-, -CO-, -8-, which is a 4@ organic group that is a membered ring and has 6 to 12 carbon atoms and may have an a substituent. -8O
,-,-CH,-,-CHlIC-9-C(CH,)
, -, etc.) are preferred examples (here, 2 is the same as Mayuki) and a kanji group having a nuclear substituent is preferred. Examples of the above-mentioned substituents include lower alkyl groups (eg, methyl, ethyl, etc.) + 7-aryl groups (eg, phenyl).

Representative examples of the compound represented by the above formula to, +21 include the following compounds.

Bislactone compound represented by formula [11 200
0 HCph II l l Ifo
0 0 0 0 0 0 phC
H However, in these structural formulas, ph means a phenol group.

Bislactone compound represented by formula (2): One or more of these bislactone compounds are used.

I can be there.

In the present invention, the preferred proportion of the bislactone compound used is about 0.05 to 5% by weight, more preferably about 0.1 to 3% by weight, based on the polyamide.

In the present invention, in order to cause the polyamide and the bislactone compound to react, they are heated in a state in which they are in close contact with each other.

The preferred temperature is 150 to 350°C, and the reaction is particularly preferably carried out while the polyamide is melted. The reaction pressure is normal pressure.

Decompression! Either pressurization may be used. In particular, when the reaction is carried out in the melt, the reaction can be carried out with stirring in a polyamide polymerization reactor, or the two may be mixed and reacted in a melt molding machine such as an extruder. Reaction time is 3
The time period is 0 seconds to 60 minutes, more preferably 1 minute to 30 minutes. The increase in the degree of polymerization (intrinsic viscosity) of the polymer after the reaction varies depending on the degree of polymerization of the initial polyamide, the amount of terminal amino groups, the amount of bislactone compound used, 9 the reaction method, etc., but usually the intrinsic viscosity is 0.1 or more, or more. Preferably, the increase is 0.2 or more, more preferably 0.3 or more, and the intrinsic viscosity of the final polymer is 1.5 or more, more preferably 2.0 or more, and the percentage is 2.5.
It is preferable to set it as above.

The polyamide of the present invention may also contain other additives, such as heat stabilizers, light stabilizers, matting agents, colorants, fillers, flame retardants, antistatic agents and other side effects. good.

According to the present invention, the molecular weight of the polyamide can be easily and quickly increased, and the molecular weight of the polyamide can be increased rapidly during the bath melt molding process, which is useful as an industrial method.

Example The present invention will be explained below with reference to Examples. .

In addition, parts in the examples mean parts by weight, and terminal amino groups [
Ml was determined by dissolving the polymer in m-cresol, neutralizing it with 0.01 N p-toluenesulfonic acid using thymol blue as an indicator, and calculating the amount of neutralization.

Reference Example 1: Synthesis example of 21.9 parts of pyromellitic anhydride and 29.9 parts of phenylacetic acid
1 part and 2 parts of acetic acid were charged into a flask equipped with a stirrer and heated to 240 to 250°C in a nitrogen stream to distill water produced by the reaction out of the system. S: After the theoretical amount of water has been distilled off, the reaction product is recrystallized from dimethylformamide, and this process is repeated to obtain a solid with a melting point of 317-325°C (BL-A).
6 parts and 4 parts of a solid (BL-B) having a melting point of 419-425°C were obtained.

- Example 2: Using 23.2 parts of benzophenone 3t4t3'+4'-tetracarboxylic dianhydride and 21.8 parts of phenylacetic acid, these were reacted in the same manner as in Reference Example 1, recrystallized with dimethylformamide, and the melting point 386-393℃ solid (BL
-C) 7 parts were obtained.

Examples 1 to 4 6100 parts of nylon with an intrinsic viscosity of 1.37 and (corner) 45 equivalents/106.9 was melted at 280°C under a nitrogen gas flow, and a predetermined amount of the bislactone compound shown in the table below was added thereto. The reaction was carried out under stirring for 10 minutes.The intrinsic viscosity of the obtained polymer is shown in the table.

Example 5 Intrinsic viscosity 1.26, (NH,) 65 equivalents/10
1.5 parts of bislactone compound BL-C was mixed with 100 parts of ## nylon 66 and melt-extruded at 280°C from an extruder. The intrinsic viscosity of the obtained polymer was 2.55. The residence time in the router during extrusion was about 6 minutes.

Claims (1)

[Claims] A polyamide having a terminal amino group and the following formulas (1) and (2)
1. A method for producing a highly polymerized polyamide, which comprises heating and reacting at least one bislactone compound represented by the following formula to increase the molecular weight of the polyamide. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・
・・・・・・(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・
......(2) [However, D in the formula is a tetravalent organic group whose ring structure is a 5-membered ring or a 6-membered ring, R_1 is a hydrogen atom or a monovalent organic group, R_2 is a monovalent organic group, R_3 is a divalent organic group whose ring structure is a 5-membered ring or a 6-membered ring,
R_4 is a divalent organic group, and both organic groups are non-reactive with polyamide. ]