JPS5822484B2 - Polyamide polyamide resin - Google Patents

Description

[Detailed description of the invention] The present invention has a hydroxyl group or a thiol group.

The present invention relates to a method for producing soluble polyamide.

Conventionally, the method for producing polyamides having hydroxyl groups or thiol groups involves adding other aliphatic or aromatic diamines, carboxylic acids, or carboxylic acids to aliphatic or aromatic dicarboxylic acids or diamines having these functional groups, respectively. Either the corresponding nylon salt is reacted, or an aqueous solution is prepared by mixing equivalent amounts of both, and these are usually prepared in a pressurized reaction vessel at a temperature higher than the melting point of the polyamide, for example, 200°C or higher, under pressure. A polycondensation reaction was carried out, and after several hours, the pressure was released and the mixture was further heated under normal pressure or reduced pressure to synthesize polyamide.

However, since the reaction temperature is high in this method, the hydroxyl group or thiol group reacts with the carboxyl group of other molecules during the polycondensation reaction to form an ester bond or a thioester bond, resulting in an insoluble or thiol group having a crosslinked structure. tends to produce an infusible polyamide, and thermal decomposition of hydroxyl groups and thiol groups also occurs, resulting in a colored decomposed polyamide, making it extremely difficult to obtain a soluble polyamide with a linear structure.

As another production method, a method is known in which the dicarboxylic acid is changed to an acid chloride, and the diamine is produced at a low temperature by a so-called interfacial polycondensation method or a low-temperature solution polycondensation method.

In this method, when a dicarboxylic acid having a hydroxyl group or a thiol group is converted into an acid chloride, the acid chloride group easily reacts with the hydroxyl group or thiol group.
Synthesis of acid chloride itself is generally extremely difficult.

Therefore, a hydroxyl group or a thiol group is introduced into the structure of the diamine, and the diamine and dicarboxylic acid chloride are polycondensed to form a polyamide.

However, even in this case, since the side reaction between the acid chloride group and the hydroxyl group or thiol group proceeds simultaneously, a polyamide having a crosslinked structure is obtained, and it is difficult to obtain a linear polyamide having a hydroxyl group or a thiol group.

The present inventor researched a method for easily synthesizing linear polyamides having hydroxyl groups or thiol groups, which was extremely difficult to synthesize using conventional methods. As a result of polycondensing diamine with the dicarboxylic acid and the carboxylic acid ester, it was found that when the dicarboxylic acid ester was used, the reactivity was significantly superior and polyamide could be obtained at a high polymerization rate at a low temperature of 100°C or less. It was.

For example, since the polycondensation reaction of tartaric acid and tartaric acid dimethyl ester with hexamethylene diamine in methanol usually involves chemical equilibrium, components that are eliminated in the polycondensation reaction, such as water and alcohol, are removed from the reaction system. Is it necessary to remove the eliminated component to shift the chemical equilibrium to the production system side? In the polycondensation reaction of the present invention, there is no need to remove the eliminated component from the reaction system, and the eliminated component, alcohol, is used as a solvent. It was found that the polycondensation reaction proceeded even if it was used.

The present invention was completed based on this knowledge.

The carboxylic acid ester and diamine W having a hydroxyl group or a thiol group used in the present invention have aliphatic,
Aromatic or heterocyclic units may also be included, and the diamine may contain a hydroxyl group or a diamine.

It may have an all group.

In addition, polycondensation occurs most easily when the substitution position of the hydroxyl group, thiol group, or thiol group is at the α position in dicarboxylic acid esters, as shown below.
Even if the functional group is located at other positions, the polyamide and condensation activities are greater than those of ordinary dicarboxylic acid esters or diamines, and polyamides are easily formed at low temperatures. Condensation activity decreases.

The number of substituted hydroxyl groups or thiol groups does not necessarily have to be the same as the number of carbonyl groups or amine groups, and may be 1/2 or the same number or more.

The ester group of the dicarboxylic acid ester having a hydroxyl group or a thiol group at the α position is an aliphatic group such as methyl or ethyl, or an aromatic group such as phenyl or pyridinyl nato, or a petrochemical group, and the type thereof is not particularly limited.

The polycondensation reaction in the present invention can be easily carried out without a catalyst, but the use of a catalyst is optional.

Examples of dicarboxylic acids of dicarboxylic acid esters having a hydroxyl group at the α position include tartaric acid, mucilage acid, and α.

Aliphatic dicarboxylic acids such as d-dioxyadipic acid, or α,α′-dioxyhomoterephthalic acid, 2,6-di(
Examples include aromatic dicarboxylic acids such as (α-oxycarboxymethyl) naphthalene.

As a diamine having a hydroxyl group, 2-oxy1.3°
Aliphatic diamines such as diaminopropane, 2,4-dioxy-1,4-diaminobutane, or 1,4-di(α-
Examples include aromatic diamines such as oxyaminomethyl)benzene and 2,6-di(aminomethyl)naphthalene.

Dicarboxylic acids of dicarboxylic acid esters having a thiol group at the α position include aliphatic and aromatic carboxylic acids such as α, α-dimercaptoadipic acid, and 1,4-di(α-mercaptocarboxymethyl)benzene. be.

Examples of diamines having a thiol group include aliphatic and aromatic diamines such as 2-mercapto-1,3-diaminopropane and 1,4-di(α-mercaptocarboxymethyl)benzene.

The linear polyamide having hydroxyl groups and/or thiol groups obtained in the present invention is soluble in ordinary polyamide solvents such as formic acid and phenol, and fibers or films can be formed from these solutions. .

Since this polyamide has hydrophilic hydroxyl or thiol groups, its hygroscopicity is significantly greater than that of ordinary polyamides, and its permeability to water vapor is high.

In addition, since it has a highly reactive hydroxyl group or thiol group, it not only has a large adsorption amount of dye molecules, but also can be reacted with various chemical reagents to make useful polymer materials, and has a wide variety of functionalities. It is a polyamide with

Next, examples of the present invention will be described.

Example 1 Equivalent amounts of methyl L-tartrate and hexamethylene diamine were dissolved in methanol at a concentration of 1 mol/l, and when stirring was continued at 30°C, the solution gradually became viscous and became cloudy in 30 minutes. The polymer begins to precipitate and eventually the whole becomes gel-like.

After 24 hours, the mixture is poured into water and filtered to obtain a white polymer with a yield of 84%.

The obtained polyamide has repeating units of tartaric acid and hexamethylene diamine, and has an intrinsic viscosity of 0.35 in m-cresol at 30°C.

This polyamide does not exhibit a fixed melting point and begins to decompose at around 210°C.

A transparent film can be made from a formic acid solution, the moisture absorption of which is 60 parts at 200C and 10 parts relative humidity.

Example 2 Equivalent amounts of methyl L-tartrate and hexamethylene diamine were dissolved in water containing 5 parts lithium chloride at a concentration of 1 mol/l, and stirring was continued at 30°C. After 30 minutes, the solution became cloudy. , the solution will eventually become gel-like.

After 24 hours, the mixture is poured into a large amount of water and filtered to obtain a white powdery polymer with a yield of 52%.

The intrinsic viscosity of the obtained polyamide in m-cresol at 30°C is 0.25.

Example 3 Equivalent amounts of methyl L-tartrate and m-xylylenediamine are dissolved in methanol at a concentration of 1 mol/l, and when stirring is continued at 30°C, the polymer gradually begins to precipitate and the solution becomes gel-like.

After 24 hours, the mixture is poured into a large amount of water and filtered to obtain a white polymer with a yield of 70%.

The intrinsic viscosity of the obtained polymer in m-cresol at 30°C is 0.35.

Example 4 Equivalent amounts of methyl α,α'-dioxyadipate and hexamethylene diamine were dissolved in methanol at a concentration of 1 mol/l, and when stirring was continued at 30°C, the polymer gradually began to precipitate and the solution becomes gel-like.

After 24 hours, the mixture is poured into a large amount of water and filtered to obtain a white polymer with a yield of 85%.

The m-cresol intrinsic viscosity of the obtained polyamide at 30°C is 0.41.

Example 5 Equivalent amounts of methyl α,α'-dioxyhomoterephthalate and hexamethylene diamine are dissolved in methanol at a concentration of 1 mol/l, and when stirring is continued at 30°C, the polymer gradually begins to precipitate.

After 24 hours, the mixture is poured into a large amount of water and filtered to obtain a white polymer with a yield of 70%.

The solution viscosity of the obtained polyamide in m-cresol at 30°C is 0.25.

Example 6 When an equivalent amount of α, αl-dithiomethyl adipate and hexamethylene diamine were dissolved in methanol at a concentration of 1 mol/l and stirring was continued, a pale yellow polymer gradually began to precipitate, and the solution It turns into a gel.

When poured into a large amount of water and filtered, a pale yellow polymer was obtained with a yield of 7.
Obtained in Section 5.

The intrinsic viscosity of the obtained polyamide in m-cresol at 30°C is 0.30.

When this polyamide is left in the air, it gradually becomes insoluble and transforms into a crosslinked polyamide having difluoride bonds.

Example 7 Equivalents of 2-oxy-1,3-propylene diamine and α,
Methyl α' dioxyadipate is dissolved in methanol at a concentration of 0.5 mol/l and stirring is continued at 60°C.

The polymer gradually begins to precipitate and the solution turns into a gel.

When poured into a large amount of water and filtered, the yield of white polymer was 65%.
You can get it in person.

The intrinsic viscosity of this polyamide in m-cresol at 30°C is 0.35.

Claims (1)

[Claims] 1. Di having a hydroxyl group or a thiol group at the α position. A method for producing a soluble polyamide, comprising polycondensing a carboxylic acid ester and a diamine at a temperature of 100° C. or lower under reduced pressure or normal pressure.