JPS602327B2 - Manufacturing method for new heat-resistant cured resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 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 25030 as measured by the method described below.
Preferably 300 or more, particularly preferably 350q
It has excellent heat resistance, with temperatures exceeding
For example, high modulus fibers (carbon fiber, aramid fiber, etc.)
When used as a reinforcing material, it can also be used as a high-performance composite material.

Conventional technology Various heat-resistant resins used in this field have been studied.

For example, polyimide resins made by reacting penzophenone, tetracarboxylic acid, nadecic acid or maleic anhydride with 4,4-diaminodiphenylmethane are well known.

However, in this case, the oligoimide before thermosetting has poor solubility in organic solvents, and also has a high melting point and high softening point, resulting in difficulties in moldability.

OBJECTS OF THE INVENTION The present invention provides a method for producing a resin with good heat resistance from an oligomer that has excellent solubility in organic solvents and has a relatively low melting point and low softening point.

Another object of the present invention is to obtain a highly heat-resistant resin that has a high concentration of crosslinking points while maintaining the molecular weight of the oligomer above a certain level.

Conventionally, in order to increase the concentration of crosslinking points without adding an amine compound, it was necessary to reduce the molecular weight of the oligomer because the crosslinking points of the oligomer exist only at the molecular ends. The present invention can avoid such inconveniences.
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 ○' 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 cured resin, which is characterized by subjecting an imide compound represented by the following formula to a heating reaction with an aromatic amine, and further with an aromatic tetracarboxylic acid and/or a reactive derivative thereof added as necessary. .

In the production of the heat-resistant cured resin of the present invention, the above-mentioned single-pronged imide compound is used;
R is a divalent group, such as a dioxyaromatic compound residue such as 1○-.-S-, -SQ1 and 1CH2- bonding group, and the like.

Further, D is an unsaturated dicarboxylic acid residue containing a carbon-carbon double bond, for example, an unsaturated carboxylic acid residue having 8 or less carbon atoms represented by 1CH=CH-.

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

The imide compound used in the production of the heat-resistant resin in the present invention is represented by the above general formula, and the preferred one as ○ is an unsaturated carboxylic acid residue represented by -CH=CH-.

Moreover, the compound where n=1 is preferable to the compound where n=1 because a resin with excellent heat resistance can be obtained. The above imide compound (in the above formula, 0, R, m, and n are the same as above) is reacted with a known dehydrochlorination agent such as sodium carbonate, triethylamine, or pyridine at a temperature of, for example, 15 to 3 pi. It can be obtained by dehydrating and ring-closing the amic acid shown in .

Although this dehydration ring reaction proceeds by heating alone, it can be obtained by a heating method reaction with an acid anhydride such as acetic anhydride at 100 to 150° C. for 3 to 1 feeding time. Amic acid can be synthesized using the above method in a sacrificial solvent such as dimethylformamide or N-methylpyrrolidone. You can go there.

The present applicant has already reported on such imide compounds in Taru 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 as a resin raw material in its unpurified state, but it can be purified using an organic solvent such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, dioxane, etc.

In producing the heat-resistant resin in the present invention, in addition to the imide compound represented by the single-pronged formula above, aromatic amines and, if necessary, aromatic tetracarboxylic acids and/or derivatives thereof are used. Here, the aromatic amine is, for example, a compound represented by the following formula [11 [where R, m, and n are the same as R, m, and n in the above general formula], and specifically, aniline, 414'-diamino Diphenylmethyl, 4.
4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ketone, 1
・3-bis(4-aminophenooxy)benzene, 1.
4-bis(4-aminophenooxy)benzene, 2.2
-bis(4-(4-aminophenooxy)phenyl)propane, etc.

In addition to pyromellitic acid, aromatic tetracarboxylic acids and reactive derivatives thereof, which may be added as necessary, can be used, for example, in the following formula {21 [where R, m, and n are R, m, and n in the above general formula] These acid anhydrides and lower aliphatic esters are known compounds conventionally used in the synthesis of polyimides.

Specifically, 3,4,3',4'-diphenyltetracarboxylic acid, 3,4,3',4'-penzophenonetetracarboxylic acid, 3,4,3',4-diphenyl ether tetra Examples include carboxylic acids. In the production of the heat-resistant cured resin in the present invention, the blending ratio of the above raw materials is such that the resin before the curing reaction has an average molecular weight (calculated value) of about 500 to
The number of unsaturated dicarboxylic acid residues ranges from about 3,000 to about 3,000, and on average contains at least one carbon-carbon double bond in the molecule. Preferably, the resin before the curing reaction has an average molecular weight (calculated value) of about 600 to about 20.
00, particularly preferably from about 800 to about 1400, and on average contains unsaturated dicarboxylic acid residues containing two or more carbon-carbon double bonds in the molecule.

If this average molecular weight (calculated value) is too small, the melting point and softening temperature of the resin before curing is low and it has excellent solubility in organic solvents, but the mechanical properties of the cured product will deteriorate. If (calculated value) is too large, the melting point and softening temperature of the uncured resin tend to be high and the solubility in organic solvents tends to decrease, resulting in poor moldability and lowering the glass transition temperature of the cured product, which is not preferable. Here, the aromatic tetracarboxylic acid and the aromatic amine form an imide bond by a conventionally known reaction, whereas the oxazinone in the imide compound represented by the general formula of the present application is formed by a conventionally known reaction between the aromatic tetracarboxylic acid and the aromatic amine. It is thought that the following reaction results in the formation of an amide bond, followed by dehydration and ring closure to form a quinazolone ring.

As the aliphatic alcohol used as the ester with the aliphatic alcohol, lower aliphatic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol and hexyl alcohol are preferably used.

Also, as an example of aromatic tetracarboxylic acid, 3.403'
・If we take 4'-benzophenone tetracarboxylic acid and methyl alcohol as an example of an aliphatic alcohol, there are four esters with that aliphatic alcohol: monoester, diester, triester, and tetraester, all of which can be used. However, in the present invention, gestal is particularly preferably used. In the present invention, a heat-resistant resin is produced by mixing the above raw materials and subjecting them to a curing reaction by heating.

Here, an organic solvent is used when mixing the raw materials.

As the organic solvent that can be used here, for example, polar solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferably used. When the above raw materials are mixed in an organic solvent and heated for a short time between room temperature and 200 qo, they react to form oligomers.

The oligomer obtained in this way is soluble in the above solvent and is obtained as a homogeneous solution, so if it is heated to remove the organic solvent, or is subjected to a curing reaction while removing the organic solvent, a heat-resistant resin is formed. can get.

This curing reaction is usually carried out during the molding process, and is carried out at a temperature above 0 DEG C., preferably between 250 and 35,000 degrees, particularly preferably between 280 and 320 degrees Celsius, for between 1 and 5 hours.

In this way, a heat-resistant resin is obtained, preferably 20
The heat resistance can be improved by post-curing at a temperature of 0 qo or higher, particularly preferably between 250 and 350°C. For example, the heat-resistant resin of the present invention may include glass fiber,
When reinforced with reinforcing materials such as carbon fiber and aramid fiber, it exhibits excellent effects as a composite material.

For this purpose, a reinforcing material is impregnated with a solution of the above-mentioned oligomer, and after or while the organic solvent is removed, a curing reaction is carried out and the reinforcing material is molded. Function The raw materials used in the present invention and the oligomers obtained from them have excellent solubility in organic solvents, and the softening point, preferably the melting point, can be adjusted to 300 qo or less, so the resin has good fluidity before curing. It has excellent moldability, and the resulting heat-resistant resin has excellent stability against thermal decomposition, probably because it has imide rings and quinazolone rings.
Moreover, it has a high glass transition point of 300°C or higher, particularly 350q0 or higher, and has excellent heat resistance.

The present invention will be further explained below with reference to Examples.

In the examples, "parts" represent "parts by weight." Example 1 136 parts of anthranilic acid was mixed with 700 parts of an aqueous solution containing 155 parts of potassium carbonate, and 35 parts of anthranilic acid was added to the rope at 35 oo or less.
00 parts dissolved in 100 parts of dimethylformamide was passed through the tube.

After dropping, the reaction was allowed to continue for 6 minutes, and then hydrochloric acid was added to cause acid splitting. The precipitated solid was separated in a furnace, washed with water, and dried to obtain an amic acid represented by the following structural formula in the mottled base portion. Next, 340 parts of acetic anhydride was added to this amic acid, and the mixture was heated under reflux for 6 hours in a nitrogen stream. This reaction mixture was dried vertically using an aspirator and recrystallized using dioxane-ethyl alcohol to obtain an imide compound having the following structural formula and having a melting point of 203 to 207°C. This compound is 1765-
A characteristic absorption based on oxazinone was observed in No. 1, and a characteristic absorption based on imide bond was observed in No. 1.

30.72 parts of the above imide compound, 7.9 parts of 4,4'-methylene dianiline, and 4 parts of dimethylformamide were added and heated at 150 qo to obtain an oligomer solution.

This solution was heated in an oven at 150 qo for 2 hours, then at 20 qo.
The solvent is removed by treatment at 0°C for 2 hours to obtain an oligomer with a melting point of approximately 180°C.The oligomer is then transferred to a molding machine, degassed under reduced pressure at 250 to 29°C, and then heated to 320°C.
The mixture was pressed for 1 hour and molded into a disc with a thickness of 3 skins. This molded product was gradually heated to 300° C. and post-cured at the same temperature for 6 hours. Here, the molded product was cut into six medium pieces, heated and boiled in a nitrogen stream using a DuPont DMA (Mmel lo90) at a boiling speed of 1020 per minute, and the glass transition point was determined.

The glass transition point of the resin thus determined was 350°C, indicating that it has good heat resistance. In addition, this resin was subjected to a 3-point bending test with a distance between fulcrums of 2 ships.
The bending strength was approximately 10k9/m.

Furthermore, this resin has a rating of 42 pi0 and 4. As a result of an accelerated test for evaluating heat resistance during storage in an oven, the weight retention rate was excellent at 82%. Example 2 31. Tomokuni and 3.96 parts of 4,4'-diami/diphenyl were heated at 150°C to dissolve and react with 4 parts of dimethylformamide to obtain an oligomer solution.

The solution obtained here was heated in an oven at 150°C for 2 hours and then at 200°C for 2 hours to remove the solvent, and the melting point was about 2.
An oligomer at 50°C was obtained. This oligomer was transferred to a molding machine, degassed at 250 to 290°C under reduced pressure, and then
It was pressurized at 20 qo for 1 hour and molded into a disk with a thickness of 3 sides.
This molded product was post-cured in the same manner as in Example 1, and the glass transition point was determined to be 390° C. or higher, indicating that it has good heat resistance. In addition, this resin was subjected to a three-point bending test with a distance between fulcrums of 2 degrees, and as a result, the bending strength was approximately 10k9. Furthermore, this resin has a rating of 42 pi0 and 4. As a result of an accelerated heat resistance test in which the material was kept in an oven for an hour, it showed an excellent weight retention rate of 80%. Example 3 23.04 parts 4,4'-diaminodiphenylmethane 9.25 parts, 3.

4.3′. 5.3 parts of 4'-penzoff/tetracarboxylic acid anhydride was mixed with 4 parts of dimethylformamide,
It was made into an oligomer solution. The oligomer solution obtained here was heated in an oven at 150° C. for 2 hours and then at 200° C. for 2 hours to evaporate the solvent, yielding an oligomer with a melting point of about 240° C.

This oligomer was placed in a molding machine, degassed under reduced pressure at 250 to 29 mm, and then pressure molded at 320° C. for 1 hour to obtain a disk having a Barcol hardness of 60 and a thickness of 3 sails. This molded product was post-cured in the same manner as in Example 1, and the glass transition point was measured.

The result was 355°C. Example 4 30.72 parts Pisu 113-(4-aminophenoxy)benzene 2
1.28 parts and 10.6 parts of 314.3'.4'-besosophenone tetracarboxylic anhydride were mixed with 6 dimethylformamide to obtain an oligomer solution.

The oligomer solution obtained here was treated in the same machine as in Example 3,
An oligomer with a melting point of about 20,000 was obtained. This oligomer was molded using the same machine as in Example 1, post-cured, and the glass transition point was found to be 320:0, and the Barcol hardness of this molded product was 50. Example 5 Used in Example 1. 15.4 parts of the oxazinone used in Example 2, 15.6 parts of the oxazinone used in Example 2, and 3.96 parts of 404-diaminodiphenylmethane were dissolved in dimethylformamide grade 4 and heated at 15°C to obtain an oligomer solution. .

This solution was heated in an oven at 150°C for 2 hours and then heated to 20°C.
The mixture was heated for 2 hours to remove the solvent, then transferred to a molding machine, degassed under reduced pressure at 250 to 29 mm, then pressurized at 32 mm for 1 hour, and molded into a disk with a thickness of 3 feet. This molded product was post-cured in the same manner as in Example 1, and the glass transition point was determined to be 380 qo, indicating that it has good heat resistance.

Further, this resin was heated in an oven at 420 pm. The weight retention rate when maintained for an extended period of time was 80%, which was excellent.

[Brief explanation of the drawing]

FIG. 1 is an infrared analysis chart of the raw imide compound before curing in Example 1, FIG. 2 is an infrared analysis chart of the cured product obtained in Example 1, and FIG. 4 is an infrared analysis chart of the cured product obtained in Example 2. FIG. 4 is an infrared analysis chart of the cured product obtained in Example 3. The figure below shows a certain mist ant.

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. ], an aromatic amine, and an aromatic tetracarboxylic acid (including its reactive derivative) added as necessary to produce a novel heat-resistant curable resin, which is characterized by subjecting it to a heating reaction. Method.