JPH11343322A - Thermosetting resin composition and molding material containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in curability, heat stability, and strengths by using a novolac phenolic resin, hexamethylenetetramine, and a substituted benzoic acid as the essential components. SOLUTION: There is provided a resin composition containing 100 pts.wt. novolac phenolic resin, 7-30 pts.wt. curing agent such as hexamethylenetetramine, and 0.1-20.0 pts.wt. substituted benzoic acid represented by the formula as the essential components and optionally containing at least one filter selected among organic materials such as a wood flour, a pulp powder, or a ground molding, inorganic powders such as silica, talc, or alumina, and inorganic fibers such as a glass fiber. The substituted benzoic acid used is exemplified by 2- nitrobenzoic acid, 2,4-dinitrobenzoic acid, 3-chlorobenzoic acid, o-cyanobenzoic acid, or 2,4-dicyanobenzoic acid. In the formula, X1 to X5 are each H or an electron-attracting group; and at least one of them is an electron-attracting group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to curability, heat stability,
The present invention relates to a thermosetting resin composition excellent in both strength and a molding material using the same. More specifically, the present invention has excellent thermal stability in a plasticizing process in a cylinder during injection molding, has excellent curability in a curing process in a mold, and has good moldability and high quality molded products. The present invention relates to a thermosetting resin composition that can be provided and a molding material using the same.

[0002]

2. Description of the Related Art Phenolic resin molding materials have excellent heat resistance, durability, electrical performance, mechanical properties, and cost performance.
It is also widely used for kitchen parts. In recent years, in the process of manufacturing molded products using phenolic resin molding materials, in order to further improve productivity, there has been a demand for the development of molding materials that can produce molded products having desired performance by short-time heat molding. ing. Conventionally, various improvements have been made to shorten the curing time of the phenolic resin molding material. For example, a method using a high-ortho novolak having a methylene chain at an ortho-ortho position relative to a phenolic hydroxyl group, and addition of a hydrochloride of an aliphatic or aromatic amine such as aniline hydrochloride, hydroxylamine hydrochloride, and metaaminophenol hydrochloride. (See, for example,
JP-A-2975), a method of adding an adduct of hexamethylenetetramine and a phenol derivative as a curing agent (for example, JP-A-54-116049). Although the curability is improved by these methods, the thermal stability is significantly reduced during the plasticizing process in the cylinder during injection molding, and continuous molding cannot be performed. Therefore, development of a thermosetting resin composition capable of improving curability and maintaining heat stability is required.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and has been made by using a thermosetting resin composition having excellent curability, heat stability and strength, and using the same. It is intended to provide a molding material. More specifically, the present invention has excellent thermal stability in a plasticizing process in a cylinder during injection molding, has excellent curability in a curing process in a mold, and has good moldability and high quality molded products. An object of the present invention is to provide a thermosetting resin composition that can be provided and a molding material using the same.

[0004]

That is, the present invention provides:
A thermosetting resin composition comprising (a) a novolak-type phenol resin, (b) hexamethylenetetramine, and (c) a substituted benzoic acid represented by the general formula [1] as an essential component, and a molding material using the same. is there. (Wherein X _{1 to} X ₅ are H or an electron withdrawing group, and at least one of X ₁ to X ₅ is an electron withdrawing group.)

Embedded image

[0005] Usually, when an acid catalyst is added to a phenolic resin molding material regardless of the type of acid such as Bronsted acid or Lewis acid as a curing accelerator, the curability in a molding machine mold is improved. , Thermal stability is reduced and continuous molding cannot be performed. However, the substituted benzoic acid represented by the general formula [1] contained in the thermosetting resin composition of the present invention is different from other acids, despite being a Bronsted acid, and has excellent curability. By using a substituted benzoic acid represented by the general formula [1], which is an acid that imparts thermal stability, the above-mentioned problem has been achieved.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The novolak type phenol resin used in the present invention is an ordinary novolak type phenol resin obtained by reacting a phenol with a formaldehyde. Examples of the applicable phenols include phenol, cresol, xylenol, naphthol, pt-butylphenol, bisphenol A, resorcinol and the like.
And polyhydric phenols and their substituted products 1
Species, or two or more species can be exemplified. On the other hand, as the corresponding formaldehyde, formalin, paraformaldehyde and the like can be exemplified. The novolak type phenol resin used in the present invention may be a resin suitably modified with an aromatic hydrocarbon resin, dimethoxyparaxylene, dicyclopentadiene or the like.

As the curing agent used in the present invention, powdery hexamethylenetetramine is used, and 7 to 30 parts by weight, more preferably 12 to 20 parts by weight of hexamethylenetetramine is mixed with 100 parts by weight of the novolak type phenol resin. I do.

The substituted benzoic acid represented by the general formula [1] used in the present invention includes 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4-nitrobenzoic acid, 2,4-dinitrobenzoic acid, 3,5 -Dinitrobenzoic acid, 2,6-dinitrobenzoic acid, 2-chlorobenzoic acid, 3-chlorobenzoic acid, 4-
Chlorobenzoic acid, 2,4-dichlorobenzoic acid, 3,5-
Dichlorobenzoic acid, 2,6-dichlorobenzoic acid, o-cyanobenzoic acid, m-cyanobenzoic acid, p-cyanobenzoic acid, 2,4-dicyanobenzoic acid, 3,5-dicyanobenzoic acid, 2,6- Dicyanobenzoic acid and the like can be mentioned, and 0.1 to 20.0 parts by weight of substituted benzoic acid is blended with respect to 100 parts by weight of a novolak type phenol resin. When the amount is 0.1 part by weight or less, the curability is not improved. When the amount is 20.0 parts by weight or more, the curability is excellent, but the thermal stability is reduced.
The substituted benzoic acid represented by the general formula [1] acts as a curing accelerator on the novolak-type phenol resin and the hexamethylenetetramine curing system, and the substituted benzoic acid and a known acidic catalyst or basic catalyst are thermally stable. It is of course possible to use them together as long as the degree does not deteriorate.

Further, various fillers known to those skilled in the art can be added to the present invention. Examples of the filler used include wood powder, pulp powder, pulverized textiles, organic materials such as thermosetting resin cured products and pulverized molded products, silica, alumina, aluminum hydroxide, glass, talc, clay, and the like. Inorganic powders such as mica, calcium carbonate, and carbon, and inorganic fibers such as glass fiber and carbon fiber are used, and one or more of these can be used. These fillers can be appropriately added as needed.

[0010]

EXAMPLES The present invention will be described below in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 To 100 parts by weight of a novolak type phenol resin (number average molecular weight 800), 16 parts by weight of hexamethylenetetramine was added, and 8 parts by weight of 2-nitrobenzoic acid was added as a curing accelerator. Wood powder and thermosetting resin powder were blended as fillers and kneaded with a heating roll to obtain a thermosetting resin molding material. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Example 2 A thermosetting resin was prepared in the same manner as in Example 1 except that 8 parts by weight of 2-nitrobenzoic acid was replaced with 8 parts by weight of 3-nitrobenzoic acid. A molding material was obtained. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Example 3 A thermosetting resin was prepared in the same manner as in Example 1 except that 8 parts by weight of 2-nitrobenzoic acid in Example 1 was replaced with 8 parts by weight of 4-nitrobenzoic acid. A molding material was obtained. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Example 4 Thermal curing was conducted in the same manner as in Example 1 except that 7.5 parts by weight of 2-chlorobenzoic acid was used instead of 8 parts by weight of 2-nitrobenzoic acid in Example 1. A resin molding material was obtained. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Example 5 Thermal curing was conducted in the same manner as in Example 1 except that 7.5 parts by weight of 3-chlorobenzoic acid was used instead of 8 parts by weight of 2-nitrobenzoic acid in Example 1. A resin molding material was obtained. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Example 6 Thermal curing was performed in the same manner as in Example 1 except that 7.5 parts by weight of 4-chlorobenzoic acid was used instead of 8 parts by weight of 2-nitrobenzoic acid in Example 1. A resin molding material was obtained. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Comparative Example 1 16 parts by weight of hexamethylenetetramine was added to 100 parts by weight of a novolak-type phenol resin (number average molecular weight 800), and wood powder and a thermosetting resin powder were mixed as fillers. The mixture was kneaded with a heating roll to obtain a thermosetting resin molding material. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Comparative Example 2 16 parts by weight of hexamethylenetetramine was added to 100 parts by weight of a novolak-type phenol resin (number-average molecular weight: 800), and 5.8 parts by weight of benzoic acid was added as a curing accelerator. Wood powder and thermosetting resin powder were blended as an agent and kneaded with a heating roll to obtain a thermosetting resin molding material. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

Comparative Example 3 16 parts by weight of hexamethylenetetramine was added to 100 parts by weight of a novolak type phenol resin (number average molecular weight: 800), and 6.6 parts by weight of salicylic acid was added as a curing accelerator. As a result, a thermosetting resin molding material was obtained by mixing wood powder and a thermosetting resin powder and kneading them with a heating roll. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

[Comparative Example 4] To 100 parts by weight of a novolak type phenol resin (number average molecular weight 800), 16 parts by weight of hexamethylenetetramine was added, and 5.3 parts by weight of resorcinol as a curing accelerator was added. As a result, a thermosetting resin molding material was obtained by mixing wood powder and a thermosetting resin powder and kneading them with a heating roll. Test pieces were prepared from this molding material by injection molding, and various characteristics were evaluated.

The curability, thermal stability, and cured product properties of the molding materials obtained in each of the Examples and Comparative Examples were measured by the following methods.

(1) Evaluation of curability Injection molding was performed at 175 ° C. using a Barcol hardness tester type 935.
After curing for 15 seconds, 25 seconds, and 40 seconds, the test piece was removed from the mold, and the surface hardness of the test piece after 10 seconds was measured. (2) Flexural strength Cured by injection molding at 175 ° C for 180 seconds, JIS K
The bending strength was measured according to 6911. (3) Evaluation of thermal stability Thermal stability was evaluated by measuring and comparing the stability duration at 100 ° C. using Toyo Seiki Labo Plastomill.

Table 1 shows the characteristics obtained in Examples 1 to 6 and Comparative Examples 1 to 4.

[0024]

[Table 1]

From Table 1, when molded with a molding material using the thermosetting resin composition of the present invention shown in Examples 1 to 6,
The Barcol hardness is higher than Comparative Examples 1 to 4, and the curability is significantly improved. The thermal stability is equal to or lower than those of Comparative Examples 1 and 2 in which the substituted benzoic acid is not added, but they are remarkably poor in curability. In addition, it is significantly improved as compared with Comparative Examples 3 and 4 in which an acid other than substituted benzoic acid was added. Examples 1 to 6 have good curability and heat stability. When the bending strength is examined, the strength tends to decrease when an acid-based catalyst is added. However, when the substituted benzoic acid is added, a large decrease in the bending strength is not observed.

[0026]

As is clear from the above examples, the thermosetting resin composition obtained by the present invention and the molding material using the same are extremely excellent in curability and heat stability. Are better. By using the thermosetting resin composition of the present invention and a molding material using the same, the curing time during molding can be significantly reduced, the molding cycle can be increased, and productivity can be improved. Can be.

Claims (8)

[Claims] (1) a novolak-type phenolic resin,
(B) hexamethylenetetramine, and (c) a general formula
A thermosetting resin composition comprising the substituted benzoic acid represented by [1] as an essential component. Embedded image (Wherein X _{1 to} X ₅ are H or an electron-withdrawing group, and X _{1 to} X ₅
At least one is an electron-withdrawing group. ) 2. A substituted benzoic acid represented by the general formula [1]:
The thermosetting resin composition according to claim 1, which is a nitro-substituted benzoic acid. 3. A substituted benzoic acid represented by the general formula [1]:
The thermosetting resin composition according to claim 1, which is a chloro-substituted benzoic acid. 4. A substituted benzoic acid represented by the general formula [1]:
The thermosetting resin composition according to claim 1, which is a cyano-substituted benzoic acid. 5. A molding material using the thermosetting resin composition according to claim 1. 6. A molding material using the thermosetting resin composition according to claim 2. 7. A molding material using the thermosetting resin composition according to claim 3. 8. A molding material using the thermosetting resin composition according to claim 4.