JPS60190425A - Preparation of crystalline polyamide based resin - Google Patents

Abstract

PURPOSE:To obtain an aliphatic-aromatic polyamide based polyamide resin having a high molecular weight and improved heat resistance and mechanical characteristic easily at a low cost, by adding a solvent to reaction raw materials, heating and reacting the raw materials which keeping the fluidity and distilling away the solvent, and carrying out the reaction under high vacuum to give a high polymerization degree. CONSTITUTION:A cystalline polyamide resin is prepared from raw materials in which either one of the diamine or dicarboxylic acid is an aromatic compound and the other is an aliphatic compound by the direct melt polymerization method. In the process, 5-50pts.wt. solvent is added to 100pts.wt. reaction raw materials, and the temperature is increased to react the reaction raw materials while keeping the fluidity and distilling away the solvent. The reaction is then carried out under high vacuum to give a high polymerization degree. The diamine component to be one of the raw materials is diaminodiphenylmethane alone or partially a mixture of m-xylylenediamine in the case of the aromatic compound or hexamethylenediamine in the case of the aliphatic compound. Adipic acid, etc. or terephthalic acid, etc. corresponding thereto may be used as the dicarboxylic acid component.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a crystalline polyamide resin in which one of the acid component and the amine component is an aromatic compound and the other is an aliphatic compound.

Extrusion molding and injection molding of aliphatic-aromatic polyamide resins is usually difficult due to the high melting point of fully aromatic polyamide resins.
However, it has a suitable melting point, is easy to mold, and has higher mechanical strength, elastic modulus, and heat resistance than fully aliphatic polyamides such as polyhexamethyleneadipamide and polycaproamide. It is expected to be used in a variety of applications as a high-performance extrusion and injection molding resin due to its high properties such as high durability, high chemical resistance, and low water absorption.

However, among these aliphatic-aromatic polyamides, crystalline resins that are expected to have high elasticity and high heat resistance and chemical resistance have not been produced until now, perhaps due to the difficulty of synthesis. However, we do not see any examples of industrialization.

Methods for synthesizing this crystalline polyamide include interfacial polycondensation using an acid chloride and an amine, solution polycondensation (υsp·-split knitting reaction 5,1.+, It 1 ), or solid phase polymerization (Mizozo at.

U, Polymer Chemistry Vol 29.159. ], 972
) have been proposed, but all of them have drawbacks such as high cost and difficulty in obtaining high molecular weight products.

On the other hand, the method using melt polycondensation, which is the most economical synthesis method, generally involves a two-step process in which a nylon salt or a precursor condensate of a low molecular weight product is produced at a relatively low temperature, and then a polymerization reaction is carried out at a high temperature. Although a high molecular weight resin is obtained through the condensation reaction, the melting point of the low molecular weight material, which is a nylon salt or a precursor condensate, is higher than its formation temperature, and it solidifies in the middle of the synthesis. That is, while these nylon salts or low molecular weight precursor condensates are produced at temperatures below 200°C or at most 220-230°C, the melting point of these products is generally above 240-250°C. However, due to solidification during the reaction, mixing in the reactor,
Stirring is stopped.

Therefore, the polymerization reaction is carried out either by the above-mentioned in-phase polymerization or by remelting the precursor condensate at a higher temperature and combining it under reduced compression. However, in the former solid phase polymerization, mixing and stirring are not performed and heating is performed for a long time, so that the raw materials are locally heated, and coloring due to thermal decomposition or oxidative decomposition and gelation due to partial crosslinking are likely to occur. In the latter method as well, since the precursor condensate is placed at a higher temperature in the remelting stage, the possibility of coloring and partial crosslinking is further increased.

In view of the current situation, the present inventors have proposed an inexpensive and easy method.
In order to develop a method for synthesizing crystalline aliphatic-aromatic polyamide resins, as a result of extensive research, we introduced a small amount of solvent to the nylon salt or low molecular weight precursor condensate of these resins.
High molecular weight resin with excellent heat resistance and mechanical properties can be obtained by keeping the fluidity of the raw material, distilling off the solvent, heating it to temperature, and then placing it under a high vacuum to carry out a high polymerization reaction. This is what I discovered.

In the present invention, the amine component that is the raw material for obtaining the target resin is m-phenylenediamine, P-
phenylenediamine, m-)luenediamine, m-xylylenediamine, 1,5-naphthalenediamine,
111-diaminodiphenylnefur, I, 11'
- sia epsilon diphenyl meta y, etc., while when aliphatic diamines are used in combination with aromatic dicarboxylic acid components, tetramethylene diamine, hexamethylene diamine, trimethylhexylylene diamine, octamethylene diamine, ino Examples include phorondiamine, or two or three of these may be used in combination.

Further, the dicarboxylic acid component used in the present invention includes aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, or derivatives thereof, and aliphatic dicarboxylic acids such as succinic acid. , adipic acid, azelaic acid, sebacic acid, or derivatives thereof;
Seeds may also be used.

In addition, the solvent used in the present invention has an affinity with the aliphatic-aromatic polyamide resin to be produced and can maintain fluidity at temperatures of 200°C or higher. Examples include phenols such as phenol, cresol, and xylenol. Examples include solvents such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, and N-methyl-2-pyrrolidone. The purpose of adding these solvents is to maintain the fluidity of the reactants, so the minimum amount that can achieve that purpose may be used, and although it varies depending on the composition, it is at most 50 parts by weight per 100 parts by weight of the raw material. parts, generally about 10 to 20 parts by weight. Adding a solvent in an amount of 50 parts by weight or more is not only unnecessary, but also hinders the temperature rise of the reactants, and depending on the resin composition, crystallization may occur during this time. Further, if the amount is less than 5 parts by weight, the effects of the present invention cannot be obtained.

These solvents are eluted as the temperature rises, but some of them remain, and only when the reactants reach the final condensation temperature while maintaining fluidity and are placed under vacuum can the entire amount be used. be done. However, depending on the composition, crystallization of the precursor condensate occurs early in the progress of the condensation reaction, so in such compositions it is necessary to increase the abyss velocity. Bumping is likely to occur, so it is preferable to raise the temperature under pressure.

However, in a composition in which the resulting resin has a melting point of 300° C. or higher, the effect of adding a solvent according to the present invention cannot be obtained and the resin solidifies during the temperature rise. In addition, aliphatic-aromatic polyamide resins have a decomposition point of several tens of degrees over 300°C or more -F.
Such resin systems are excluded from the present invention, which is intended to be a polyamide resin that can be produced and processed at low cost and in a temperature range of .degree. C. or lower.

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

In addition, the intrinsic viscosity in the examples is measured in a sulfuric acid solution system maintained at 55°C. Note that all parts hereinafter refer to parts by weight.

Comparative Example 1 A steamer equipped with a reflux condenser, a stirrer, and a nitrogen inlet pipe
295 parts of diaminodiphenylmethane, 295 parts of azelaic acid, and 27 parts of Irganox 109 g (manufactured by Ciba Geigy) as a heat aging inhibitor were supplied to a reactor manufactured by Les, and heated while flowing nitrogen gas into the container. 1
When the temperature reached 20°C, stirring was started. Next, when the temperature of the contents reached 150°C, the reflux condenser attached to the reactor was switched to the elution pipe and heating was continued. After about an hour and a half, when the temperature of the contents reached 255°C, The contents solidified and became impossible to stir.

A portion of the contents was taken out at this time and the melting point was measured by DSC, and it was found to be 278°C.

After this, Ceritone was heated to 10℃, which is the reactor wall temperature, and heating was continued. After about 2 and a half hours, the content temperature reached 290℃ and when it became possible to stir with fingers, decompression was started, and nitrogen gas The reaction was carried out at 20 Torr for about 0 minutes while allowing a slight inflow of nitrogen gas, and then the reaction was continued for about 2 hours with the inflow of nitrogen gas stopped.

Thereafter, the inside of the reactor was pressurized to extrude the produced resin and taken out while cooling with water. The resin product thus obtained was partially colored and gel formation was observed.

In addition, the intrinsic viscosity of this resin is 0.55 t5L/grD
The melting point at SC was 270°C.

Example 1 In the same reactor used in Comparative Example 1, 295 parts of diaminodiphenylmethane, 293 parts of azelaic acid, 1098.27 parts of Irganox as a heat aging inhibitor, m-
57 parts of cresol was supplied, and heating and stirring to 120°C were started. After about 40 minutes, the content temperature reaches 150℃.
At ~ ~, the reflux piping was switched to the elution piping, and about 1 hour later, the content temperature reached 220°C. In this state, some of the cresol begins to be used, but the heating reaction continues, and approximately 5
After 0 minutes, the content temperature reached 250°C, and the volume of cresol increased, and when it reached 260°C, it reached about 110°C.
There was a section of cresol for the section.

The heating reaction was further continued, and when the temperature of the contents reached 290° C., pressure reduction was started and the reaction was carried out at 20 Torr for about 30 minutes while a slight amount of nitrogen gas was introduced into the reactor.

During this period, almost all of the cresol was used.

Further, the decompression was continued for about 1 hour and 30 minutes until the degree of vacuum became I Torr or less, and the reaction was completed. As in Comparative Example 1, when pressure was applied with nitrogen gas and the resin was taken out while cooling with water, a yellowish-white, transparent, and uniform resin was obtained.

The intrinsic viscosity of the resin thus obtained was 0.71647g.
, r, the melting point measured by DSC was 272°C. In addition, when the mechanical properties of this resin were measured using the method specified by ASTM, the tensile strength was 980 kgr/c! It showed an elongation of 15%.

Comparative Example 2 In the same reactor as used in Comparative Example 1, 1.911 parts of dimethyl terephthalate, dimethyl isophthalate, ],
q it part, hexamethylene diamine, 2 ++,
4 parts of water, 300 parts of water, and 1098.19 parts of Irganox were heated and stirred in refluxing water at 100°C for about 5 hours, then the reflux piping was switched to the distillation piping and the reaction was continued. After about an hour and a half, when the temperature of the contents reached 220°C, it became impossible to stir the mixture.

Continue to raise the temperature of this material by 1 hour until it solidifies, and after about 1 hour, 2
When the temperature reached 90°C, decompression was started and the degree of vacuum reached 1. The reaction was continued for 11 hours at a temperature below Torr (1-).

The resin obtained by smelting has a brown color at the top of the reactor.
The lower part was white crystals. When the intrinsic viscosity of the resin in the lower white crystalline portion was measured, it was found to be 011164/gr, and the melting point was 294°C.

Example 2 In addition to adding 65 parts of m-cresol to the reactor, the same raw material composition as in Comparative Example 2 was used, and the mixture was stirred and heated at 100° C. for 5 hours under water reflux to react.Then, the reflux piping was switched to the distillation piping. , After about 1 and a half hours of temperature-raising reaction, the content temperature was 220
It has reached ℃. After about an hour, the temperature continued to rise to 290-29
When the temperature reached 5° C., decompression was started. During this time,
Turret ξ stirring was normal.

While nitrogen gas was slightly introduced into the reactor, the pressure was reduced to 20 Torr for 30 minutes. This one hour m-
Almost all of the cresol was used. Thereafter, the inflow of nitrogen gas was stopped, the temperature was raised to 295 to 500°C, and the compression was continued for another 1 hour, and the reaction was terminated when the degree of vacuum became 1 Torr or less.

Then, the resin was taken out of the reactor in the same manner as in Example 1.

The resin thus obtained was white, transparent, and uniform, and had an intrinsic viscosity of 0.56 g, r/rEL, and a melting point of 281°C.

As in Example 1, the mechanical properties of the resin were measured. Tensile strength 811Ofr/crl Elongation: 8% Met.

As shown in the Examples below, the method of the present invention allows for the production of crystalline polyamide resins that are easy to operate, cost low, and have excellent properties, and is extremely useful industrially.

Claims (3)

[Claims] (1) When producing a crystalline polyamide resin in which one of the diamine or dicarboxylic acid components is an aromatic compound and the other is an aliphatic compound by a direct melt polymerization method, 5 to 50 parts by weight of the diamine or dicarboxylic acid component is added to 100 parts by weight of the reaction raw material. While maintaining the fluidity of the melt by adding parts by weight of solvent and distilling off the solvent,
1. A method for producing a crystalline polyamide resin, which comprises carrying out a temperature raising reaction and then carrying out a high polymerization reaction under high vacuum. (2) The diamine component is diaminodiphenylmethane alone or a mixture in which diaminodiphenylmethane is partially replaced with m-xylylene diamine, and the diamine component is a dicarboxylic acid component, adipic acid, sebacic acid, azelaic acid, or a group of derivatives thereof. The method for producing a crystalline polyamide resin according to claim 1, characterized in that one or a mixture of two or more of the selected resins is used. (3) The diamine component is hexamethylene diamine, and the dicarboxylic acid component is terephthalic acid, inophthalic acid, or a mixture of two or more selected from the group of derivatives thereof.