JPH0834850A - Production of polyamide - Google Patents

Abstract

PURPOSE:To obtain a polyamide without using an expensive diamine, without requiring a great deal of a strong acid, and without requiring complicated operations after the reaction by thermally reacting a glycol having a hydroxyl group at the benzyl position with a dinitrile compd. CONSTITUTION:A glycol having a hydroxyl group at the benzyl position is thermally reacted with a dinitrile compd. to provide the polyamide. An arom. dinitrile compd. is pref. for obtaining a polyamide excellent in thermal properties and chemical stability. The reaction can be conducted in the presence of a catalyst. An acid or an acid producing complex salt can be used as the catalyst without any problem. Though the reaction can be conducted in the absence of a solvent, a diluent can be used for controlling the reaction rate or for modifying the viscosity.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a polyamide. More specifically, a semi-aromatic polyamide having particularly excellent thermal properties, mechanical properties, and chemical stability,
The present invention relates to a simple manufacturing method.

[0002]

2. Description of the Related Art Polyamides such as nylon 6 have an excellent balance in mechanical properties, moldability, chemical stability, etc. and are used as molding materials for electric / electronic devices and automobile parts. It is also used as an important material in various industrial fields such as tapes, sheets, films and fibers.

At present, a general method for producing polyamide is generally a polycondensation method using a dicarboxylic acid and a diamine or a dicarboxylic acid chloride and a diamine. In this production method, it is absolutely necessary to remove the elimination components such as water and hydrochloric acid generated during the reaction. Therefore, the polycondensation method has theoretical problems such as a low ratio of the product obtained to the charged raw material and the need for an apparatus for removing the eliminated components. Another feature of these polycondensation methods is the use of diamines as raw materials. Generally, diamines are produced from an alkyl halide and ammonia or produced by hydrogenating dinitrile. Since the reaction route and the purification method are complicated, the cost is high. Therefore, these production methods using diamines are expensive methods.

As an example of such a polycondensation reaction, a method of producing by a direct polycondensation method using an aromatic diamine and an aliphatic dicarboxylic acid as starting materials (Japanese Patent Publication No. 01-1492).
No. 5), a method for producing by a direct polycondensation method using an aliphatic diamine and an aromatic dicarboxylic acid as starting materials (Japanese Patent Publication No.
No. 3-65205), and a method of producing by an interfacial polycondensation method or a solution polycondensation method using an aliphatic diamine and an aromatic dicarboxylic acid chloride as starting materials.

On the other hand, as a method for producing without generation of elimination components, a method for producing a polyamide by reacting a glycol having a secondary hydroxyl group and a dinitrile in a large amount of strong acid (US-2,628, 216) or an adamantane derivative having two hydroxyl groups (having a secondary and / or tertiary hydroxyl group) and a dinitrile in a large amount of a strong acid to produce a polyamide (Japanese Patent Publication No. 45-2024).
Is disclosed. However, these methods are complicated and costly production methods because it is necessary to recover the polyamide from the strong acid after the reaction.

[0006]

SUMMARY OF THE INVENTION In order to solve the problems in the conventional methods for producing polyamides, expensive diamines are not used, a large amount of strong acid is not required, and separation after the reaction is complicated. As a result of earnest research on a method for producing a polyamide that does not require various operations, the inventors have found that a polyamide can be obtained by heating a glycol (A) having a hydroxyl group at the benzyl position and a dinitrile (B), and accomplished the present invention.

[0007]

That is, the present invention is a method for producing a polyamide, characterized in that a glycol (A) having a hydroxyl group at the benzyl position and a dinitrile (B) are heated and reacted.

The glycols (A) having a hydroxyl group at the benzyl position used in the present invention are aromatic compounds having one alcoholic hydroxyl group at each of two benzyl positions in one molecule. The attached carbon is 1
Any of grade 2, grade 3, and grade 3 may be used. Examples of such glycols (A) having a hydroxyl group at the benzyl position include paraxylylenediol, metaxylylenediol, orthoxylylenediol, 3,6-bis (hydroxymethyl) dulene, and 2,3-bis. (Hydroxymethyl) naphthalene, 9,10-bis (hydroxymethyl)
Anthracene, 2,2'-biphenyldimethanol,
2,2′-bis (hydroxymethyl) diphenyl ether, 1,3-bis (α-hydroxyethyl) benzene,
1,4-bis (α-hydroxyethyl) benzene, 1,
3-bis (α-hydroxyisopropyl) benzene,
1,4-bis (α-hydroxyisopropyl) benzene and the like can be mentioned. These glycols (A) having a hydroxyl group at the benzyl position may be used alone or in combination of two or more.

The glycol having a hydroxyl group at the benzyl position (A) used in the present invention may be used in combination with other glycols. In that case, the glycol having a hydroxyl group at the benzyl position (A) is 80 in order to promote the desired reaction.
It is necessary that the content be at least% by weight, preferably 90% by weight or more.

There are no particular restrictions on other glycols that can be used in combination with the glycol (A) having a hydroxyl group at the benzyl position used in the present invention. For example, ethylene glycol, 1,3-propanediol, 1,4-butane. Diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,2-propanediol, 1,2-butanediol, 2, Examples include 3-butanediol, 2,5-hexanediol, diethylene glycol, 4-hydroxymethylphenethyl alcohol and the like. These glycols may be used alone or in combination with the glycol (A) having a hydroxyl group at the benzyl position.

Dinitriles (B) used as a raw material of the present invention
Is not particularly limited as long as it is a dinitrile, for example, aliphatic dinitriles such as succinonitrile, glutaronitrile, and adiponitrile, phthalonitrile, isophthalonitrile, terephthalonitrile, 2,6-dicyanotoluene, 2, Aromatic dinitriles such as 6-dicyanonaphthalene, 4,4′-biphenyldicarbonitrile and 2,5-dicyanoparaxylene can be mentioned, and in particular, to obtain a polyamide having excellent thermal characteristics and chemical stability. Has
It is preferable to use aromatic dinitriles as the dinitriles (B). These dinitriles (B) may be used alone or in combination of two or more.

The use ratio of the raw material of the present invention is preferably in the range of 0.3 to 1.5 moles of dinitriles (B) with respect to 1 mole of glycols (A) having a hydroxyl group at the benzyl position. The range of 0.8-1.2 mol is preferable.
When the use ratio of the dinitriles (B) is less than this range, a high molecular weight polyamide may not be obtained and it may be difficult to obtain sufficient physical properties. If the proportion of the dinitriles (B) used is higher than this range, side reactions may precede and the resin may become insoluble, making molding processing difficult.

The present invention uses alcohols having one or three or more hydroxyl groups and nitriles having one or three or more cyano groups for the purpose of adjusting the final viscosity and the viscosity during the reaction. You can In that case, the amount used is within 20% by weight, more preferably 10% by weight, of alcohols having 1 or 3 or more hydroxyl groups and nitriles having 1 or 3 or more cyano groups.
It is preferably within the range.

In the present invention, if the heating temperature is too low, the desired reaction may not proceed, or other reactions may precede and the physical properties of the resin may deteriorate. On the other hand, if the heating temperature is too high, a side reaction or a decomposition reaction may occur to deteriorate the physical properties of the resin. Therefore, the heating temperature is 80 ° C or higher and 320
The temperature is preferably in the range of 0 ° C or lower, and particularly preferably in the range of 130 ° C or higher and 300 ° C or lower.

When the glycols (A) having a hydroxyl group at the benzyl position of the present invention and the dinitriles (B) are reacted by heating, the reaction can be carried out in the presence of a catalyst. As the catalyst, there is no problem as long as it is an acid or a complex salt capable of generating an acid. The acid as used herein refers to both Bronsted acid and Lewis acid. Bronsted acid is a substance that releases a proton, for example, hydrochloric acid, sulfuric acid, fuming sulfuric acid, phosphoric acid,
Examples thereof include trifluoromethanesulfonic acid. The Lewis acid is a substance that receives an electron pair, and examples thereof include boron fluoride, aluminum chloride, iron chloride, zinc chloride, tin chloride and the like. These acids are 1
One kind or a combination of two or more kinds can be used.

The amount of the catalyst used is preferably more than 0 parts by weight and 5 parts by weight or less based on 100 parts by weight of the dinitriles (B). If it is not added, the desired reaction rate may not be obtained, and if it exceeds 5 parts by weight, problems such as deterioration of physical properties of the obtained polyamide may occur, so that a complicated purification step is required. Will be needed.

When the glycols (A) having a hydroxyl group at the benzyl position and the dinitriles (B) of the present invention are reacted by heating, the reaction can be carried out without a solvent, but for the purpose of controlling the reaction rate or adjusting the viscosity, etc. A reaction diluent solvent can be used. As the reaction diluent solvent, various organic solvents can be used. There is no particular limitation on the type of solvent, but a dipolar aprotic substance such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidinone, hexamethylphosphoamide, dimethylsulfoxide or diphenylsulfoxide, which can dissolve the obtained polyamide well. Solvents are preferred.

In the present invention, the reaction can be carried out at normal pressure, but in order to shorten the reaction time, it is also possible to carry out the reaction in a closed container under a pressure higher than atmospheric pressure.

In the present invention, additives such as pigments, crystal nucleating agents, plasticizers, and ultraviolet absorbers can be used depending on the method of using the resulting resin. The addition timing of the additive is not particularly limited and may be before the reaction, during the reaction, or after the reaction.

The present invention is not particularly limited by the method of adding raw materials, the type of reactor, the method of stirring, the method of taking out the resin and the method of refining.

[0021]

EXAMPLES The present invention will be described below with reference to examples, but the scope of the present invention is not limited to these examples.

Example 1 In a 1-liter stainless steel container equipped with a stirrer, a thermometer, a pressure reducing valve, and a nitrogen gas introducing valve, 138 g (1) of paraxylylenediol as a glycol (A) having a hydroxyl group at the benzyl position was prepared. Mol), 128 g (1 mol) of isophthalonitrile as the dinitriles (B) and 266 g of N-methyl-2-pyrrolidinone as the solvent. The container was purged with nitrogen gas at room temperature and heated at 280 ° C. for 8 hours while stirring. After heating, the contents were taken out and put into 2 liters of ethyl acetate. The precipitate was dried under reduced pressure to obtain 197 g of a powder solid. Yield 74%
Met. Perkin Elmer Fourier Transform IR16
It was confirmed to be polyamide by the 00 series (hereinafter, simply abbreviated as IR). (Infrared absorption spectrum is shown in FIG. 1.) Further, N-methyl-2-pyrrolidinone as a reaction solvent and ethyl acetate as a precipitation solvent could be easily recovered by distillation and could be reused.

Example 2 In a 1-liter stainless steel container equipped with a stirrer, a thermometer, a pressure reducing valve, and a valve for introducing nitrogen gas, 138 g of metaxylylenediol (1) as a glycol (A) having a hydroxyl group at the benzyl position. Mol), 128 g (1 mol) of terephthalonitrile as the dinitriles (B), and 266 g of N-methyl-2-pyrrolidinone as the solvent. The container was purged with nitrogen gas at room temperature and heated at 280 ° C. for 8 hours while stirring. After heating, the contents were taken out and put into 2 liters of ethyl acetate. The precipitate was dried under reduced pressure to obtain 189 g of a powder solid. 71% yield
Met. It was confirmed to be polyamide by IR. The reaction solvent N-methyl-2-pyrrolidinone and the precipitation solvent ethyl acetate were easily recovered by distillation and could be reused.

Example 3 In a 1-liter stainless steel container equipped with a stirrer, a thermometer, a pressure reducing valve and a nitrogen gas introducing valve, 173 g of paraxylylenediol (1) as a glycol (A) having a hydroxyl group at the benzyl position was used. .3 mol), 93 g (0.7 mol) of terephthalonitrile as dinitriles (B)
And N-methyl-2-pyrrolidinone 266 as a solvent
I charged g. The container was purged with nitrogen gas at room temperature and heated at 280 ° C. for 8 hours while stirring. After heating, the contents were taken out and put into 2 liters of ethyl acetate. The precipitate was dried under reduced pressure to obtain 104 g of a powder solid.
The yield was 54% (converted to terephthalonitrile). I
By R, it was confirmed to be a polyamide. Further, the reaction solvent N-methyl-2-pyrrolidinone and the precipitation solvent ethyl acetate can be easily recovered by distillation,
It could be reused. Example 4 In a 1-liter stainless steel container equipped with a stirrer, a thermometer, a pressure reducing valve, and a valve for introducing nitrogen gas, 117 g of paraxylylenediol (0.8 mol) as a glycol (A) having a hydroxyl group at the benzyl position was used. ), 149 g (1.1 mol) of terephthalonitrile as a dinitrile (B) and N-methyl-2-pyrrolidinone 2 as a solvent.
66g was charged. The container was purged with nitrogen gas at room temperature and heated at 280 ° C. for 8 hours while stirring. After heating, the contents were taken out and put into 2 liters of ethyl acetate. The precipitate was dried under reduced pressure to obtain 115 g of a powder solid. The yield was 51% (converted to paraxylylenediol). It was confirmed to be polyamide by IR. The reaction solvent N-methyl-2-pyrrolidinone and the precipitation solvent ethyl acetate were easily recovered by distillation and could be reused.

Example 5 In a 1 liter glass four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet, 138 g of paraxylylenediol as a glycol (A) having a hydroxyl group at the benzyl position was used. (1 mol), 128 g (1 mol) of isophthalonitrile as a dinitrile (B) and 266 g of N-methyl-2-pyrrolidinone as a solvent were charged. The inside of the container was replaced with nitrogen gas at room temperature and heated at 200 ° C. for 24 hours while stirring. After heating, the contents were taken out and put into 2 liters of ethyl acetate. The precipitate was dried under reduced pressure to obtain 128 g of a powder solid. Yield 48
%Met. It was confirmed to be polyamide by IR. The reaction solvent N-methyl-2-pyrrolidinone and the precipitation solvent ethyl acetate were easily recovered by distillation and could be reused.

Example 6 In a 1-liter stainless steel container equipped with a stirrer, a thermometer, a pressure reducing valve, and a valve for introducing nitrogen gas, 138 g of paraxylylenediol (1) as a glycol (A) having a hydroxyl group at the benzyl position was used. Mol), 128 g (1 mol) of isophthalonitrile as the dinitriles (B), and 0.29 g (1 mmol) of antimony oxide as the acid. The inside of the container was replaced with nitrogen gas at room temperature, and the mixture was heated at 280 ° C. for 4 hours while stirring. After heating, 190 g of N-methyl-2-pyrrolidinone was charged and dissolved, and then the content was taken out and put into 2 liters of ethyl acetate.
The precipitate was dried under reduced pressure to obtain 130 g of a powder solid. The yield was 49%. It was confirmed to be polyamide by IR. Further, N-methyl-2-pyrrolidinone as a diluting solvent and ethyl acetate as a precipitating solvent could be easily recovered by distillation and could be reused.

[0027]

INDUSTRIAL APPLICABILITY The production method of the present invention can easily provide a semi-aromatic polyamide having excellent thermal characteristics, mechanical characteristics, and chemical stability, and therefore can be used as a molding material for electric / electronic devices and automobile parts. Alternatively, it can be widely used in various industrial fields such as tapes, sheets, films and fibers.

[Brief description of drawings]

FIG. 1 is an infrared (IR) spectrum of the polyamide obtained in Example 1 of the present invention.

Claims (4)

[Claims] 1. A method for producing a polyamide, which comprises reacting a glycol (A) having a hydroxyl group at the benzyl position with a dinitrile (B) by heating. 2. The production method according to claim 1, wherein an aromatic dinitrile is used as the dinitrile (B). 3. The production method according to claim 1, wherein an acid is used as a reaction catalyst and the amount of the acid is used in the range of more than 0 and not more than 0.05 part by weight with respect to the dinitriles (B). . 4. The production method according to claim 1, wherein the reaction is performed using a dipolar aprotic solvent as the reaction diluent solvent.