JPS61155428A - Production of polyimide resin - Google Patents

Abstract

PURPOSE:To obtain a polyimide of a high MW and good properties reading, by subjecting 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride and a prim. diamine to dehydration and imidation by ring closure in a phenolic solvent. CONSTITUTION:3,4-Dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride (TDA) and a prim. diamine are subjected to dehydration and imidation by ring closure in a phenolic solvent. Solvents having an atmospheric b.p. of about 170-300 deg.C and a m.p. <=45 deg.C are preferable, and examples include cresol and 2,4-dimethylphenol. As said prim. diamines, any of aromatic ones (e.g., 4,4'- diaminodiphenylmethane) and aliphatic ones (e.g., ethylenediamine) can be used. TDA and the diamine are used preferably in equimolar amounts.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing polyimide resin.

[Prior Art] Polyimide resins have been attracting a lot of attention in recent years because of their excellent heat resistance, but because they are generally expensive, their use is still limited. Tetracarboxylic acid or its acid anhydride, which is a raw material for polyimide resin, is octavalent, and 3,4-dicarboxy-1,2,3,4-
Tetrahydro-1-naphthalene succinic anhydride (hereinafter referred to as 1' DA) is a compound that can be synthesized relatively easily from styrene and maleic anhydride through the Diels-Alder reaction, and is a promising raw material for polyimide wood. be.

As a method for producing polyimide resin using TDA, polyamic acid is produced in dimethylformamide, pyridine, dimethylacetamide, or dimethyl sulfoxide,
There is a method (Japanese Patent Publication No. 45-37994) in which reprecipitation is performed in a solvent in which polyamic acid does not dissolve (for example, water, ethyl acetate, etc.), followed by thermal dehydration and imidization.

Furthermore, a method (US Pat. No. 3,501,443) has also been proposed in which 11111 is imidized simultaneously with heat dehydration in a solvent such as acetonephenone, cyclohexanone, or isophorone.

The former method requires re-precipitation, and because TDA is asymmetrical, one amide bond is broken due to the water produced during heating and dehydration, making it difficult to form a polyimide resin with the product molecule m. have shortcomings.

Although there is no need for reprecipitation, the polyimide produced has a high viscosity and is difficult to handle, and the strength of molded products or films is not very high.

] Problem 1 to be Solved by the Invention In view of the above-mentioned problems, the present inventors proposed to develop a method for producing a polyimide resin that is simple, simple, and has good physical properties. After further investigation, they discovered that the intended purpose could be achieved by using a phenolic compound as a reaction medium, and completed the present invention.

That is, an object of the present invention is to provide a novel method for producing a polyimide resin, in which the 'vg feature is dehydration and ring-closing imidization of TDA and 1@diamine in a phenolic solvent.

[Means for solving the problem] The phenolic solvent used in the present invention has a boiling point of 170 at normal pressure.
~300°C, and any substance with a melting point of 45°C or less may be used. Specifically, cresol (0-1m-, D-143, and a mixture thereof vIJ), 2,4-dimethylphenol, and Bromophenol (0-, m-, D monolithic and mixtures thereof), Bromophenol (0-, m-,
A single solvent such as hydroxytoluene or a mixture of the above-mentioned solvents is used.

Further, the primary diamine used in the present invention may be either aromatic or aliphatic, and aromatic examples include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, and 4,4'-diaminodiphenyl ether. , phenylenediamine (m-, C) and mixtures thereof), xylylenediamine (m-, D and mixtures thereof), 4,4-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, fat Examples of the group include ethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, dodecamethylenediamine, di(varaminocyclohexyl)methane, and the like, used alone or in mixtures, but are not limited to these.

The molar ratio of diamine and TDA is preferably equal to 1, but even if one is in excess of a few percent, it is possible to cover a sufficiently strong polyimide resin if the reaction is carried out carefully.

Next, typical manufacturing conditions for polyimide resin will be explained in detail.

(1) TDA and primary diamine are reacted at a temperature of 15 to 45°C, preferably 20 to 25°C, for 1 to 10 hours to produce polyamic acid. If the temperature is higher than 45°C, the molecular weight of the polyamic acid tends to decrease, and if the temperature is lower than 15°C, the viscosity of the system increases, making stirring difficult.

(2) After that, gradually v4 wet, and finally perform dehydration and ring-closing imidization at a temperature of 200 ° C. for 0.5 to 10 hours,
Generates polyimide resin.

It is preferred to use a solvent that is azeotropic with water, such as xylene, to facilitate dehydration.

(3) Although the reaction atmosphere can be air, it is preferably an inert gas such as nitrogen gas in order to suppress coloring of the final product, the resin.

[Example 1 The present invention will be explained in detail with reference to Examples below.

Example 1 TDA30.03! J (0.1 mol), 4.4-diaminodiphenylmethane 19.839 (0°1 mol)
in 150 g of cresol under nitrogen atmosphere for 20~
The reaction was carried out at 25°C for 2 hours with stirring, the temperature of each body was raised, xylene 259 was added at 90°C, the temperature was raised to 200°C over 2 hours, and the reaction was further carried out at 200°C for 2 hours. During this period, 28 g of distilled water and xylene were collected through a condenser. The polyimide VAIllWI solution thus obtained was coated onto a glass plate, heated at 100°C and 10gm+HG for 1 hour, and then heated for 20 hours.
The cresol was removed under conditions of 0° C. and 10 gmHQ for 1 hour to obtain a polyimide film with a thickness of 50 μm.

Example 2 30.03 g (0.1 mol) of TDA, 20.03 g (0.1 mol) of 4.4"-diaminodiphenyl ether
The reaction was carried out in 50 g of 0-chlorine 1-nor under a nitrogen atmosphere at 20-25°C with stirring for 2 hours, and then the temperature was gradually raised, and 25 g of xylene was added at 90°C.
The temperature was raised to 5°C over 2 hours, and the reaction was continued at 175°C for an additional 2 hours.

During this period, water and xylene distilled out passed through a condenser and 289 ml of the water was recovered. The polyimide resin solution quantitatively obtained in this way was applied onto a glass plate and heated to 80°C.
, 1 hour at 10 as HQ, then 200℃, 10 shoes HQ
The 0-chlorophenol was removed under the following conditions for 1 hour to obtain a polyimide film with a thickness of 50 uTrL.

Example 3 The polyimide resin solution prepared in Example 1 was applied to a glass plate and heated at 80°C and normal pressure for 3 hours, and at 100°C and normal pressure for 3 hours.
Time, 100℃, 1 hour with 10 shoes, 1 liter, 200℃, -
The cresol was removed under 10 aw HO for 1 hour to obtain a polyimide film with a thickness of 1 liter.

Comparative Example 1 79.2 g (0.4 mol) of 4,4-diaminodiphenylmethane was dissolved in 470 g of pyridine, and 1209
of TDA (0.4 mol) is added over a period of 4 hours, keeping the reaction temperature below 35°C.

A viscous solution forms and is diluted with 189 g of pyridine. The polyamic acid produced was precipitated in ethyl acetate, collected by filtration, and converted to polyimide by heating to 200° C. in vacuo.

Further, pressure molding was performed at 300° C. and 100 kg/− to obtain a polyimide resin plate with a thickness of 1 jwI.

Comparative Example 2 15.62 SF (0.52 mol) of TDA, 4°4'
14.109 (0.52 mol) of -diaminodiphenylmethane were stirred in 7cetophenone at a temperature below 165°C for 2 hours. During this period, 3.6 g of water distilled out was collected through a condenser.

The polyimide resin solution thus obtained was applied onto a glass plate, heated at 100°C for 1 hour at 10 feet of HQ, and then heated for 2 hours.
Acetophenone was removed under the conditions of 00° C. and 10#lHQ for 1 hour to obtain a polyimide film.

Table 1 shows the physical property values of the polyimide films and polyimide mlillii obtained in Example 1.2.3 and Comparative Example 1.2.

The imide conversion rate is determined from the ratio of the absorbance at <1770 cm-' based on the absorption of imide groups in the infrared absorption spectrum and the absorbance at <1720 cm-' based on the absorption of amide M%.

The molecular weight is expressed as a polystyrene-equivalent number average molecular weight determined by gel permeation chromatography.

[Effect of the invention 1] As described above, the polyimide resin prepared using a phenolic solvent has a high imide conversion rate, has a molecular weight of 8, and is excellent in terms of tensile strength regardless of whether it is at room temperature or high temperature. it is obvious.

Claims (1)

[Claims] Production of a polyimide resin characterized by dehydrating and ring-closing imidation of 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride and a primary diamine in a phenolic solvent. Method.