JPS602326B2 - Manufacturing method for new heat-resistant cured resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL FIELD The present invention relates to a method for producing a novel heat-resistant cured resin.

The heat-resistant cured resin of the present invention is a thermosetting resin, and has a glass transition temperature of 250° C. or higher, preferably 300° C. or higher, particularly preferably 35,000° C. or higher, as measured by the method described below.
It has excellent heat resistance, and can be used as a high-performance composite material when high-modulus fibers (carbon fiber, aramid fiber, etc.) are used as a reinforcing material.

BACKGROUND OF THE INVENTION Various heat-resistant resins used in this field have been studied.

For example, '1} Penzophenonetetracarboxylic acid,'
21 Nadec acid or maleic anhydride and legs 4.4
Polyimide resins made by reacting '-diaminodiphenylmethane are well known. However, in this case, the oligoimide before thermosetting had poor solubility in organic solvents, high kudder points, and poor moldability.

OBJECTS OF THE INVENTION The present invention provides a resin that has excellent solubility in organic solvents, does not generate created substances such as water during thermosetting, and has good heat resistance from an oligomer with a relatively low melting point, and a method for producing the same. .

Structure of the Invention The present invention is based on the general formula [wherein R is a divalent group, D is an unsaturated dicarboxylic acid residue containing a carbon-carbon double bond, and D' is obtained by removing one hydrogen atom from D. m and n are each 0 or 1.

] This is a method for producing a novel heat-resistant resin, which is characterized by heating and curing an imide compound represented by the following.

In the method for producing a heat-resistant cured resin of the present invention, the prepolymer before the curing reaction is a novel imide compound represented by the above general formula.

In the above formula, R is a divalent group, for example −○−, 1S−, 1 SQ 1 and 1 C ratio one bonding group and It is a dioxyaromatic compound residue such as.

Further, D is an unsaturated dicarboxylic acid residue containing a carbon-carbon double bond, for example, an unsaturated dicarboxylic acid residue having 8 or less carbon atoms represented by -CH═CH-.

D' is a group obtained by removing one hydrogen atom from the above D. m,
n is 0 or 1, respectively. Specific examples of the compound represented by the above general formula include compounds represented by the following structural formula.

In the present invention, the above-mentioned imide compound is used for producing a heat-resistant resin. The above-mentioned imide compound gives a cured resin with high heat resistance even if it is heat-cured alone, but among the above-mentioned single-pronged imide compounds, the imide compound with n=0 can be used in combination with the imide compound with n=1. Curing by heating is preferred (it goes without saying that the n:1 imide compound provides a sufficient heat-resistant cured resin just by heating alone).

The mixing ratio of the imide compound with n=0 is in the range of 1% to 100% with respect to the imide compound with n=1, preferably 5 to 50%.
Used in the range of %.

In the above single-pronged type of the present invention, D is preferably -CH=C
Particularly preferred is an unsaturated dicarboxylic acid residue represented by H-.

The above-mentioned imide compound is prepared by removing the unsaturated dicarboxylic acid residue represented by (however, in the above formula, D, R, m, and n are the same as above) using a known dehydrochlorination agent such as sodium carbonate, triethylamine, or pyridine. It is obtained by reacting with 5 to 30 q○.

It can be obtained by dehydrating and ring-closing the amic acid shown below.

Although this dehydration/opening reaction proceeds by heating alone, it can be obtained by heating the mushroom with an acid anhydride such as acetic anhydride at 100 to 150 qo for 3 to 1 field of mushrooms. In the above method, amic acid can be synthesized in a polar solvent such as dimethylformamide or N-methylpyrrolidone, or by dissolving it in water and adding a solution of dimethylformamide, N-methylpyrrolidone, etc. You may go.

The present applicant has already reported on such imide compounds since Samurai Gansho 5.
No. 7-149873, the contents of which are also included in the present disclosure. The imide compound of the above general formula obtained here can be used unpurified as a raw material for curing resin, but it can be purified using an organic solvent such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, dioxane, etc. can. The imide compound of the above general formula obtained here is cured by heat molding at a temperature of 200 DEG C. or above, preferably between 250 and 350 o'clock, to give a heat-resistant resin.

This heating is preferably carried out under pressure for 1 to 5 hours. Under such conditions, resin molded products can be obtained, preferably at least 200 qo, particularly preferably from 250 to 35 qo.
Heat resistance can be improved by post-curing at a temperature between.

Further, in molding the imide compound, known reinforcing materials such as glass fibers, carbon fibers, and aramid fibers can be used.

The reinforcing material may be used as short fibers or long fibers. The imide compound of the above general formula of the present invention is dissolved in an organic solvent as necessary and impregnated into a reinforcing material,
Molding can be performed after or while removing the organic solvent.

Examples of such solvents include (i) halogenated hydrocarbons such as chloroform and tetrachloroethane (ii) cyclic ethers such as tetrahydrofuran and dioxane (iii) aliphatic amides such as dimethylformamide, N-methylpyrrolidone and dimethylacetamide; Phenols such as phenol and cresol can be mentioned.

Function: The imide compound of the present invention has an oxazinone ring of appropriate polarity as well as an imide ring, so it is soluble in organic solvents such as chloroform, dioxane, dimethylformamide, N-methylpyrrolidone, etc., and has excellent solubility. Since the melting point can be adjusted to 300° C. or less, the resin has good fluidity before curing, which has excellent moldability, and since by-products such as water are not generated during molding, molded products with few voids can be obtained.

In addition, the heat-resistant resin obtained here has excellent stability against thermal decomposition, a high glass transition temperature, and excellent heat resistance, probably because it has an oxadiene ring of appropriate polarity as well as an imide ring.

The present invention will be further explained below with reference to Examples. In the examples, "parts" represent "parts by weight." Example 1 5 parts of 5,6-methylene bisanthranilic acid was dissolved in 200 parts of an aqueous solution containing 51 parts of potassium carbonate, and 10 parts of dimethylformamide was dissolved in 35 parts of dimethylformamide at 35°C or below. The solution was added dropwise.

After dropping, the reaction was continued for 60 minutes while keeping the lid closed, and then hydrochloric acid was added to cause acid precipitation. The precipitated solid was separated in a furnace, washed with water, and dried to obtain 107 parts of an amic acid represented by the following structural formula. Next, 100 parts of acetic anhydride was added to this amic acid, and the mixture was heated and refluxed for 6 hours in a nitrogen stream. The reaction mixture was then concentrated to dryness using an aspirator, and a solid was precipitated using dioxane methyl alcohol to obtain 75 parts of an imide compound having the following structural formula and having a melting point of 190 to 19 points.

In this compound, a characteristic absorption based on oxazinone was observed at 176&ka-1, and a characteristic absorption due to imide bond at 171/n-1 was observed.

The above imide compound was transferred to a press molder and molded into a disk with a thickness of 3 bars at 320° C. for 1 hour under a pressure of 10 k9/base according to a conventional method.

The molded product obtained here had a Barcol hardness of 58.

This molded product was placed in a 300qo oven, post-cured for 6 hours, then cut into 6 middle ribs, and heated using a DuPont DMA (Mmello90) at a heating rate of 1/min.
The temperature was increased at 0qo in a nitrogen stream, and the glass transition point was determined. The glass transition point of this resin determined in this way is 39
It can be seen that the temperature is 0°C or higher, indicating that it has excellent heat resistance.

In addition, this resin was subjected to a three-point bending test with a fulcrum viewing distance of two ships, and the bending strength was approximately 10 kg/bait.

Furthermore, this resin has a temperature of 4. As a result of an accelerated heat resistance test in which the resin was kept in an oven for an hour, the weight retention rate of the resin was excellent at 78%. Example 2 Two types of imide compounds represented by the following formulas were mixed, and then 320
Heat cured for 1 hour under pressure of 0.10kg/ground to a thickness of 3.
It was molded into a rib disc.

The molded product obtained here had a Barcol hardness of 62. This molded product was placed in an oven at 300°C and post-cured for 6 hours in the same manner as in Example 1. The glass transition point of the resin was determined to be 39 and 0 or higher, indicating excellent heat resistance as in Example 1. I understand that. Also, this resin has a temperature of 4
．． An accelerated test for evaluating heat resistance during storage in an oven for an hour was conducted, and as a result, the weight retention rate of the resin was excellent at 1%.

[Brief explanation of the drawing]

FIG. 1 is an infrared analysis chart of oxazinone (before curing) used in Example 1, and FIG. 2 is an infrared analysis chart of the cured product obtained in Example 1. Box* Army

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [However, in the formula, R is a divalent group, D is an unsaturated dicarboxylic acid residue containing a carbon-carbon double bond, D' is a group obtained by removing one hydrogen atom from D, and m and n are each 0 or 1. ] A method for producing a novel heat-resistant cured resin, which is characterized by heat-curing an imide compound represented by the following.