JPH06145417A - Phenolic resin molding material - Google Patents

Abstract

PURPOSE:To provide a subject material comprising a phenolic resin, hexamethylene tetramine, a specific imidazole compound, and a filler, and excellent in the thermal stability in a plasticized melted state in the cylinder of an injection molding machine and in curability in a mold. CONSTITUTION:The objective composition comprises (A) a phenolic resin, (B) hexamethylenetetramine as a curing agent for the component A, (C) an imidazole compound selected from a hydroxymethyl group-having imidazole compound and its derivatives (e.g. 2-phenyl-4-methyl-5-hydroxymethylimidazole), and (D) a filler in a weight ratio of 100:12-20:3-10:50-150, respectively. The component A is preferably an ordinary novolak phenolic resin obtained by the reaction of a phenolic compound with a formaldehyde compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol resin molding material excellent in molding processability and curability, and particularly in injection molding, the curing reaction hardly progresses in the cylinder of the injection molding machine, and The present invention provides a phenol resin molding material having extremely excellent molding processability that cures extremely quickly.

[0002]

2. Description of the Related Art Phenolic resin molding materials are excellent in heat resistance, electrical performance, mechanical performance and the like, and are therefore used in a wide range of applications such as automobile parts, electronic / electrical parts and mechanical parts. However, the conventional phenol resin molding material is 9
In the molten state plasticized to 0 to 125 ° C., the viscosity increases due to the progress of the curing reaction of the resin in the material.
It has the property of losing fluidity in minutes, and the thermal stability of the plasticized molten resin is extremely low. Therefore, when a conventional phenol resin molding material is injection-molded, there is a problem that the plasticization-melted molding material in the cylinder of the injection molding machine is significantly inferior in thermal stability and an appropriate molding condition range is extremely narrow. Conventionally, various methods such as increasing the fluidity of the molding material have been known as a method for solving this problem. However, if the thermal stability in the plasticized and molten state is improved, it is 150-
The curing reaction at 200 ° C. slows down, and conversely, when the curability in the mold is improved, the thermal stability becomes poor, and the thermal stability in the plasticized and molten state and the curability in the mold are reduced. It is difficult to obtain a phenol resin molding material in which both of the above are simultaneously improved.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides various kinds of phenol resin molding materials having excellent molding processability in which both thermal stability in a plasticized and molten state and curability in a mold are improved. The result of the study was that the purpose of the phenol is particularly excellent in the thermal stability in the plasticized molten state in the cylinder in injection molding, and the curability in the mold is extremely excellent. To provide a resin molding material.

[0004]

The present invention provides one of imidazole compounds selected from (a) phenolic resins, (b) hexamethylenetetramine, (c) hydroxymethyl group-containing imidazole compounds or derivatives thereof. The present invention relates to a phenol resin molding material having remarkably excellent moldability, which comprises two or more kinds of (d) filler. As the phenol resin of the present invention, a normal novolac type phenol resin obtained by reacting phenols with formaldehyde is used. The phenols of the phenol resin include phenol, cresol,
One or more of monohydric and polyhydric phenols such as xylenol, naphthol, pt-butylphenol, bisphenol A, resorcin and their substituted compounds can be exemplified. Examples of the formaldehydes include formalin and paraformaldehyde. Further, as the phenol resin of the present invention, those modified with aromatic hydrocarbon resin, dimethoxyparaxylene, dicyclopentadiene and the like can be used.

As the hexamethylenetetramine of the present invention, a powdery one used as a curing agent for ordinary phenol resins is used, and 7 to 30 parts by weight, preferably 12 to 20 parts by weight, relative to 100 parts by weight of the phenol resin is used. Used by blending. Examples of the imidazole compound having a hydroxymethyl group of the present invention include 2-phenyl-4-methyl-5-hydroxymethylimidazole and 2-phenyl-
Examples thereof include compounds such as 4,5-dihydroxymethylimidazole. Derivatives of these compounds are derivatives obtained by condensation of a hydroxymethyl group of these imidazole compounds and a phenol compound, and examples of the phenol compound include phenol,
Examples thereof include monovalent phenol compounds such as cresol, divalent phenol compounds such as bisphenol F, bisphenol A and resorcin, and polyvalent phenol compounds such as novolac resins. In the present invention, one or more imidazole compounds selected from the above-mentioned hydroxymethyl group-containing imidazole compounds or derivatives thereof can be used, and the phenol resin 10
0 to 15 parts by weight, preferably 3 to 10 parts by weight
It is used by blending parts by weight. If the blending amount is too small, the curability becomes insufficient, and if the blending amount is too large, the thermal stability is impaired and various properties of the molded article are deteriorated.

As the filler of the present invention, organic materials such as wood powder, pulp powder, pulverized products of various fabrics, pulverized products of thermosetting resin laminates and molded products, silica, alumina, aluminum hydroxide, glass, Inorganic powders such as talc, clay, mica, calcium carbonate, and carbon, and inorganic fibers such as glass fiber, carbon fiber, and asbestos are used, and one or more of these can be used. These fillers are used by mixing 50 to 150 parts by weight with respect to 100 parts by weight of the phenol resin. In the present invention, additives such as a flame retardant, a coloring agent, and a release agent can be appropriately mixed and used as necessary. Further, in the present invention, if necessary, a phenol compound such as a resole type phenol resin, resorcin, bisphenol F or biphenol can be appropriately mixed and used within 20 parts by weight with respect to 100 parts by weight of the phenol resin. The phenol resin molding material of the present invention comprises a phenol resin, hexamethylenetetramine, an imidazole compound having a hydroxymethyl group or a derivative thereof, a filler and various additives, and melt-kneaded with a roll mill, a twin-screw kneader, or the like. After cooling, it can be pulverized and manufactured.

[0007]

The function of the phenol resin molding material of the present invention is 90 to 1
It is remarkably excellent in thermal stability in a plasticized and melted state at 25 ° C., and is extremely excellent in curability in a mold at 150 to 200 ° C. The reason for this is not clear enough, but the imidazole compound having a hydroxymethyl group or a derivative thereof does not participate in the curing reaction between the phenol resin and hexamethylenetetramine at the temperature of the plasticizing and melting state of the resin,
To promote this reaction as a curing catalyst at high temperature in the mold, and at high temperatures, these compounds themselves react with phenol resin and hexamethylenetetramine to chemically bond and participate in resin curing. It is believed that

[0008]

EXAMPLES The present invention will be described below with reference to examples. Here, "parts" represent parts by weight. [Example 1] 44 parts of novolak resin (number average molecular weight 800) obtained by the reaction of phenol and formaldehyde, 7 parts of hexamethylenetetramine powder, 2-phenyl-4,
5-dihydroxymethylimidazole 7 parts, wood flour 30
Parts, 10 parts of calcium carbonate and 2 parts of a releasing agent were mixed, melt-kneaded with a two-roll mill, cooled and pulverized to obtain a phenol resin molding material. Example 2 Instead of 2-phenyl-4,5-dihydroxymethylimidazole of Example 1, 2-phenyl-4 was used.
Using 7 parts of -methyl-5-hydroxymethylimidazole, a phenol resin molding material was obtained in the same manner as in Example 1.

[Example 3] 2-phenyl-of Example 1
2 instead of 4,5-dihydroxymethylimidazole
A phenol resin molding material was obtained in the same manner as in Example 1 by using 14 parts of a derivative obtained by addition-condensing two resorcins to -phenyl-4,5-dihydroxymethylimidazole. [Comparative Example 1] 44 parts of novolac resin (number average molecular weight 800) obtained by the reaction of phenol and formaldehyde, 7 parts of hexamethylenetetramine powder, and 4 parts of calcium hydroxide.
Parts, 32 parts of wood powder, 11 parts of calcium carbonate, and 2 parts of a release agent were mixed, melt-kneaded with a two-roll mill, cooled and pulverized to obtain a phenol resin molding material.

Table 1 shows the material properties of the phenolic resins obtained in Examples 1 to 3 and Comparative Example 1.

[Table 1]

The thermal stability shown in Table 1 represents the thermal stability of the molding material in the plasticized and molten state, and was measured by the following method. 28 g of a powdery molding material is charged into a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) kept at 100 ° C., the rotor is rotated to plasticize and melt the molding material, and the torque of rotor rotation is measured. The torque increases as the viscosity increases with the progress of curing of the resin, and finally the fluidity is lost and the torque rapidly increases. The time from the start of measurement to the sudden rise in torque was measured, and this time was defined as thermal stability. The longer the time, the better the thermal stability. The curability in Table 1 represents the curing speed of the molding material in the mold, and a transfer molding machine having a cavity with a diameter of 50 mm and a thickness of 3 mm and having a mold kept at 175 ° C. was used for high frequency. 40g was prepared by charging 30g of tablet-shaped molding material that was preheated to 100-105 ° C with a preheater.
Molded for 2 seconds, taken out of the molded product, and the hardness of the molded product after 10 seconds was measured by a Barcol hardness tester No. It was measured at 935. The higher the hardness, the faster the curing speed and the better the curability.

From Table 1, the phenol resin molding materials of the present invention shown in Examples 1 to 3 are extremely excellent in thermal stability and curability as compared with the conventional phenol resin molding material of Comparative Example 1. You can see that In addition, Examples 1 to 3
And injection molding the phenolic resin molding material of Comparative Example 1,
When the molding machine was stopped on the way and the molding material in the plasticized and molten state was allowed to stand in the cylinder as it was, after all the materials of Examples 1 to 3 were left for 90 minutes, when the molding machine was restarted, However, when the material of Comparative Example 1 was left for 30 minutes, it hardened in the cylinder and it was difficult to restart.

[0012]

As can be seen from the above examples, the phenol resin molding material of the present invention has extremely excellent thermal stability in the plasticized and molten state and curability at high temperature. For this reason,
Particularly in injection molding, the progress of the curing reaction of the plasticized molten resin in the cylinder of the injection molding machine is significantly suppressed, and it rapidly cures in the mold, so it can be applied to a wide range of molding conditions and has excellent molding processability. ing. Further, the phenol resin molding material of the present invention is extremely suitable for sprue / runnerless molding because it has extremely excellent thermal stability in a plasticized and molten state.

Claims (1)

[Claims] 1. An imidazole compound selected from (a) a phenol resin, (b) hexamethylenetetramine, (c) an imidazole compound having a hydroxymethyl group or a derivative thereof, and (d) a filling. A phenolic resin molding material containing an agent.