JPH09291199A - Thermosetting resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermosetting resin compsn. reduced in the decrease in strength after heat hysteresis, and improved in mechanical strength, moldability and heat resistance by using a specific phenolic resin and an aramid fiber. SOLUTION: 1mol of phenol, 0.2-1.3 mol of aldehyde, and an arom. amine in an amt. of 0.2-100 pts.wt. per 100 pts.wt. phenol are subjected to an addn. condensation reaction in the presence of an acid or metal salt catalyst to obtain a phenolic resin. 100 pts.wt. phenolic resin is blended with 3-20 pts.wt. hexamethylenetetramine as a curing agent and 1-500 pts.wt. aramid fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition used for obtaining a molded product having excellent moldability and heat resistance, and a composite material such as a friction material.

[0002]

BACKGROUND OF THE INVENTION Phenolic resins are binders having excellent mechanical properties, electrical properties, heat resistance, adhesiveness, etc., and are used in various applications such as electric / electronic parts, housing construction materials and automobile parts. In recent years, the applications in the fields used under more severe conditions have increased rapidly, and the demand for heat resistance has become particularly strict. In such applications, the heat resistance of conventional phenolic resins is not sufficient, and various modified phenolic resins have been actively researched.

It is said that the thermal decomposition of the phenol resin is caused by the oxidative thermal decomposition at the methylene bridge between the phenol nuclei, and the heat resistance is improved by replacing one side of the methylene bridge with an aromatic hydrocarbon having no phenolic hydroxyl group. To be done. That is, in the reaction of phenol and aromatic hydrocarbon, the heat resistance of the phenol resin increases in proportion to the amount of modification of the aromatic hydrocarbon. However, if the modification amount of the aromatic hydrocarbon is increased, the content of the phenolic hydroxyl group is decreased as a whole, so that the adhesiveness with the substrate is deteriorated, the moldability is deteriorated due to the decrease in reactivity, and the flow curability due to the increase in molecular weight is Defects such as deterioration were increased, and sufficient heat resistance as a composite material could not be obtained.

On the other hand, composite materials such as molded products and friction materials using phenolic resin are generally made of glass fiber, aramid fiber, metal fiber or other base material and barium sulfate, calcium carbonate, wollastonite, copper powder or the like. Inorganic additives are used. The heat resistance of the composite material is expressed by the chemical heat resistance of the phenol resin used as the binder and the reinforcing effect of these base materials and fillers.

It has been revealed that the chemical heat resistance of the phenol resin is improved by introducing an aromatic hydrocarbon having no phenolic hydroxyl group into the structure of the resin as described above. However, due to the modification with an aromatic hydrocarbon, the adhesiveness with the substrate is lowered, and particularly the adhesiveness with the aramid fiber is remarkably reduced.

[0006]

The present invention has been completed as a result of various studies in order to solve the problems of the phenolic resin, and the object is to improve the moldability and heat resistance. It is intended to provide a thermosetting resin composition used for obtaining an excellent molded product, a composite material such as a friction material.

[0007]

The present invention relates to a thermosetting resin composition comprising a phenol resin obtained by using phenols, aldehydes and aromatic amines as essential components and a specific amount of aramid fiber, As a result, heat resistance as a composite material such as a molded product and a friction material is dramatically improved. That is, the present inventors have found that the phenolic resin used in the present invention has an aromatic amine in the structure,
This amino group has excellent adhesion to aramid fiber,
The present invention has been completed by finding that a reinforcing effect can be obtained by blending a specific amount of aramid fiber with a phenol resin having an aromatic amine, and further chemical heat resistance can be expressed by the amino group of the aromatic amine in the phenol resin. It came to.

Hereinafter, the present invention will be described specifically.
In the present invention, the phenols used in the phenol resin are phenol, cresol, xylenol, ethylphenol, propylphenol, catechol, resorcin, hydroquinone, bisphenol A, bisphenol F, naphthol, etc., which may be used alone or in 2 parts.
You may use it in combination of more than one kind. Aldehydes are
Formaldehyde, paraformaldehyde, benzaldehyde, acetaldehyde, saltylaldehyde, trioxane, etc. may be used alone or in combination of two or more kinds. Aromatic amines include phenylenediamine, aniline, aminonaphthalene, diaminonaphthalene, mesidine, methylaniline, methanilic acid, aminoindane, aminophenol, and bisanilinefluorene. These can be used alone or in combination of two or more. May be.

In the above-mentioned phenol resin, the aromatic amine is preferably 2 to 100 parts by weight with respect to 100 parts by weight of the phenols, and when the amount is 2 parts by weight or less, sufficient adhesion to the substrate cannot be obtained, while 100 parts by weight. Above, the hardening of the resin is hindered. The addition amount of aldehyde depends on the amount of aromatic amine, but is usually 0.2 with respect to 1 mol of phenols.
Is about 1.3 mol, preferably 0.5 to 0.9. If it is less than 0.2 mol, the skeleton as a resin cannot be sufficiently obtained, while if it exceeds 1.3 mol, the fluidity of the resin is lost and molding becomes difficult, and further, gelation occurs during the reaction to the resin. There is. As a catalyst for the addition condensation reaction of the phenol resin of the present invention, acids such as oxalic acid, hydrochloric acid, sulfuric acid, diethylsulfuric acid and paratoluenesulfonic acid, and metal salts such as zinc acetate can be used alone or in combination of two or more kinds. .

As the curing agent for the phenol resin, various bifunctional or higher functional epoxy compounds, isocyanates, formaldehyde resin and hexamethylenetetramine can be used if necessary, but hexamethylenetetramine is preferable from the viewpoint of curability and heat resistance. Is preferred. The amount of hexamethylenetetramine added is 3 to 20 parts by weight, preferably 7 to 17 parts by weight, based on 100 parts by weight of the phenol resin. If the amount is less than 3 parts by weight, the resin will be insufficiently cured,
On the other hand, if it exceeds 20 parts by weight, the decomposition gas of hexamethylenetetramine swells or cracks the molded product.

In the present invention, a thermosetting resin composition is obtained from the phenol resin and a specific amount of aramid fiber.
The aramid fiber used is a homopolymer of para-phenylene-terephthalamide (trade name: Kevlar, Twaron),
Or para-phenylene terephthalamide and 3,4 '
-A copolymer of diphenyl terephthalamide (trade name: Technora).

Aramid fiber is an organic fiber excellent in strength, elastic modulus and heat resistance, and when used as a reinforcing material for a composite material, a composite material excellent in strength and heat resistance is obtained as compared with other organic fibers and inorganic fibers. be able to. In the present invention, the phenolic resin has an aromatic amine in its structure. Since this amino group has a large affinity with the amide group of the aramid fiber, it is excellent in the adhesiveness between the phenol resin and the aramid resin. Therefore, a greater reinforcing effect can be obtained by blending a specific amount of aramid fiber with a phenol resin having an aromatic amine.

The amount of the aramid fiber added in the present invention is 1 to 500 parts by weight based on 100 parts by weight of the phenol resin,
It is preferably 15 to 350 parts by weight. If it is less than 1 part by weight, the reinforcing effect by the aramid fiber, which is a feature of the present invention, cannot be obtained. On the other hand, if the amount is 500 parts by weight or more, the fluidity of the composition at the time of molding becomes poor and molding becomes difficult.

The composite resin composition of the present invention can be used as a molding material, a glass fiber reinforced plastic, an organic fiber reinforced plastic, an inorganic fiber reinforced plastic, a rubber reinforcing material, an abrasive material, a friction material, and an electronic / electrical component coating material. , Sliding members, epoxy resin raw materials and epoxy resin curing agents.

[0015]

The present invention will be described below with reference to examples. However, the present invention is not limited to these examples. Moreover, all "parts" and "%" described in the production examples, examples and comparative examples indicate "parts by weight" and "% by weight".

Production Example 1 A reactor equipped with a stirrer, a reflux condenser and a thermometer was charged with 1000 parts of phenol and 10 parts of oxalic acid, and the temperature was raised to 80.
After adding 200 parts of phenylenediamine and 550 parts of 37% formaldehyde at ℃, the temperature was gradually raised to 95
After reaching 0 ° C., a reflux reaction was performed for 180 minutes. Then
While performing the atmospheric pressure dehydration reaction, the temperature in the system was raised to 130 ° C. Next, while dehydrating the inside of the system under a vacuum of 650 mmHg, when the temperature inside the system rose to 160 ° C., it was taken out from the reactor to obtain 1050 parts of a solid resin at room temperature.

Production Example 2 A resin 1300 which is solid at room temperature was produced in the same manner as in Production Example 1 except that 200 parts of phenylenediamine was changed to 500 parts of aniline.
Got a part.

Production Example 3 1000 parts of phenol was added to the same reactor as in Production Example 3
After charging 630 parts of 7% formalin and 20 parts of oxalic acid, the temperature was gradually raised, and after the temperature reached 95 ° C, a reflux reaction was carried out for 120 minutes. Next, while dehydrating the inside of the system under a vacuum of 650 mmHg, when the temperature inside the system rose to 170 ° C., it was taken out from the reactor to obtain 1080 parts of a solid resin at room temperature.

Example 1 To 1000 parts of the resin obtained in Production Example 1 was added 110 parts of hexamethylenetetramine and the mixture was pulverized to obtain a powder resin. 100 parts of this powder resin was dry mixed with 100 parts of aramid fiber (Kevlar manufactured by DuPont) to obtain a thermosetting resin composition.

Example 2 To 1000 parts of the resin obtained in Production Example 2 was added 110 parts of hexamethylenetetramine and the mixture was pulverized to obtain a powder resin. 100 parts of this powder resin was dry mixed with 100 parts of aramid fiber (Kevlar manufactured by DuPont) to obtain a thermosetting resin composition.

Example 3 To 1000 parts of the resin obtained in Production Example 1 was added 110 parts of hexamethylenetetramine and the mixture was pulverized to obtain a powder resin. To 100 parts of this powder resin, 150 parts of aramid fiber (Kevlar manufactured by DuPont) was dry-mixed to obtain a thermosetting resin composition.

Example 4 To 1000 parts of the resin obtained in Production Example 1 was added 110 parts of hexamethylenetetramine and the mixture was pulverized to obtain a powder resin. To 100 parts of this powder resin, aramid fiber (Teijin Co., Ltd.)
100 parts of Technora Co., Ltd.) was dry-mixed to obtain a thermosetting resin composition.

Comparative Example 1 110 parts of hexamethylenetetramine was added to 1000 parts of the resin obtained in Production Example 3 and pulverized to obtain a powder resin. 100 parts of this powder resin was dry-mixed with 100 parts of calcium carbonate to obtain a thermosetting resin composition.

Comparative Example 2 110 parts of hexamethylenetetramine was added to 1000 parts of the resin obtained in Production Example 3 and pulverized to obtain a powder resin. 100 parts of this powder resin was dry mixed with 100 parts of aramid fiber (Kevlar manufactured by DuPont) to obtain a thermosetting resin composition.

The five thermosetting resin compositions obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were used at a temperature of 160 ° C. and a pressure of 20.
A test piece was prepared by molding at 0 kg / cm 2 for 10 minutes and then baking at 180 ° C. for 3 hours. Table 1 shows the evaluation results by the normal bending strength and the bending strength after the heat history of the test pieces of the obtained five kinds of resin compositions.

[0026]

[Table 1]

As is clear from Table 1, Examples 1 to 4
Has a high normal strength, and the reinforcing effect of the aramid fiber is clear. Further, it can be seen that the bending strength after heat history is little deteriorated and the heat resistance is excellent.

[0028]

EFFECT OF THE INVENTION The phenol resin composition of the present invention has a high mechanical strength and a small decrease in strength after heat history, and is therefore suitable for use as a composite material such as a molded product and a friction material having excellent moldability and heat resistance. To be done.

Claims (2)

[Claims] 1. A thermosetting resin composition comprising 100 parts by weight of a phenol resin obtained by reacting phenols, aldehydes and aromatic amines as essential components and 1 to 500 parts by weight of aramid fiber. 2. The thermosetting resin composition according to claim 1, comprising 100 parts by weight of the phenol resin and 15 to 300 parts by weight of aramid fiber.