JPH05156122A - Thermosetting molding material - Google Patents

Abstract

PURPOSE:To obtain a thermosetting molding material which is excellent in flowability, gives a molding with no or little occurrence of flash, and therefore can be widely used as a molding material with good moldability. CONSTITUTION:The objective thermosetting molding material consists mainly of a polynuclear phenolic compound composed of at least three nuclei or a phenolic compound composed mainly of this compound, a curing agent, and an organic or inorganic filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting molding material containing a phenol compound containing a trinuclear or higher polynuclear phenol compound as a main component as a binder.

[0002]

2. Description of the Related Art A phenolic resin molding material is a typical thermosetting resin molding material. Phenolic resin molding materials have excellent mechanical strength, heat resistance, electrical characteristics, and the like, and are therefore used in a wide range of applications such as mechanical parts, electric parts, and automobile parts.

When molding a phenolic resin molding material,
Since the phenolic resin is a condensation type thermosetting resin, there are the following problems that cannot be found in the usual molding of thermoplastic resins. (1) During curing, after the molding material has melted, the melt viscosity increases and it takes a certain amount of time for it to gel and harden, so avoid burrs from the parting surface of the mold during that time. I can't. (2) Since gas such as ammonia is generated during curing,
Since it is necessary to provide an air vent on the parting surface of the mold, the occurrence of burrs here is particularly large. (3) The viscosity of the molding material increases from melting to gelling,
Since the time is several tens of seconds or more, the molding cycle becomes long. In particular, burrs generated in molded products require a great deal of labor for their removal, which increases the cost of this molded product, and while phenolic resin molding materials have excellent properties, they are a major obstacle to the expansion of demand. It was.

[0004]

Therefore, the present invention has been completed by various studies with the main purpose of reducing the occurrence of burrs during molding. When the molding material is melt-cured, the gel is rapidly formed. It is possible to suppress the generation of burrs.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a thermosetting molding material containing a phenol compound containing a trinuclear or higher polynuclear phenol compound as a main component, a curing agent, and an organic or inorganic filler as a main component. Is the gist. In the present invention, the polynuclear phenol compound having three or more nuclides includes the following compounds, but is not limited thereto. These polynuclear phenol compounds undergo a condensation reaction with a curing agent such as hexamethylenetetramine (hereinafter referred to as hexamine) to cure.

[0006]

[Chemical 1]

Therefore, the polynuclear phenolic compound can be obtained as a thermosetting molding material by blending an organic or inorganic filler and other additives in a blend with a curing agent such as hexamine. When the melting point of the polynuclear phenol compound is as high as, for example, 200 ° C. or higher, melt kneading may be difficult by a usual method. Therefore, if necessary, the melting point may be lowered by using other polynuclear phenol compound in combination. You can Examples of such polynuclear phenol compounds include other trinuclear or higher phenol compounds, binuclear phenol compounds, novolac type phenol resins, and resole type phenol resins. When two or more phenol compounds having three or more nuclei are used, their mixing ratio is arbitrary. When a trinuclear or higher phenol compound and a dinuclear phenol compound are used, it is preferable to use a trinuclear or higher phenol compound in an amount of 50% by weight or more. When using a trinuclear or higher phenol compound and a novolac type phenol resin or a resol type phenol resin, 70 wt% or more of the trinuclear or higher phenol compound is used in order to maintain good fluidity. Is preferred.

A polynuclear polynuclear compound having three or more nuclides, a curing agent, a filler and the like are mixed, and a conventional method, that is, a roll,
A molding material is obtained by melt-kneading with an extruder or a Henschel mixer and then pulverizing. When used as a molding material, this melting point is considerably lower than the melting point of the polynuclear phenol compound. Since such a polynuclear phenol compound is crystalline, a molding material using it is quickly melted by heating at the time of molding and becomes a liquid substance having low viscosity and excellent fluidity. And the increase in viscosity is small for a certain period of time,
At a certain point, the curing reaction occurs rapidly, leading to gelation and curing. For this reason, when a molding material is formed in the same manner as a normal phenol resin molding material, a low-viscosity fluidized state is obtained at the time of molding. Therefore, it is preferable to reduce the molding pressure in order to prevent burrs.

On the other hand, when the curing is slow and the low-viscosity fluid state continues for a long time during molding, the reaction between the polynuclear phenol compound and the curing agent is promoted when the molding material is formed or after the molding material is heated to heat it. If the reaction is stopped at a stage slightly before the start of the reaction, when this molding material is molded, it becomes a low-viscosity liquid substance by heating, and then the curing reaction is promptly started to lead to gelation. Therefore, even if molding is performed with a low pressure, filling is completed in a short time, and burrs can be prevented from being generated by rapid curing. Further, the molding cycle can be shortened.

The filler used in the present invention is an organic substance such as wood powder, pulp powder, various pulverized products of woven fabric, pulverized products of thermosetting resin laminates and molded products, silica, alumina, glass, talc, clay. Powders such as calcium carbonate and carbon, and inorganic substances such as glass fiber, carbon fiber and mica are used.

[0011]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples. Here, "parts" indicate parts by weight. [Example 1] 44 parts of trisphenol PA, 7 parts of hexamine, 3 parts of calcium hydroxide, 32 parts of wood powder, 11 parts of calcium carbonate, and 3 parts of a mold release agent were mixed, melted and kneaded with a roll, and then at 150 ° C. It was heated for 10 minutes, cooled, and then pulverized to obtain a molding material. Example 2 A molding material was obtained in the same manner as in Example 1 except that 44 parts of trisphenol PA was replaced with 35 parts of trisphenol PA and 9 parts of bisphenol A.

[Example 3] A molding material was obtained in the same manner as in Example 1 except that 44 parts of trisphenol PA was replaced with 35 parts of trisphenol PA and 9 parts of novolac type phenol resin (number average molecular weight 800). [Comparative Example 1] A molding material was obtained in the same manner as in Example 1, except that novolac type phenol resin (number average molecular weight 800) was used instead of trisphenol PA and heating after kneading was not performed.

The fluidity (viscosity measured by a Koka type flow tester) was measured for each of the obtained molding materials. Furthermore, transfer molding was performed under the following conditions, and the presence or absence of burrs was measured. The results are shown in Table 1. (Transfer molding condition) 20 g of tableting molding material was preheated to about 100 ° C., a transfer molding die having the shape shown in FIG. 1 was used, and a gauge pressure of 25 kg / cm ² (comparative example was 50 kg / cm ² ) and a temperature. Molded at 200 ° C. for 3 minutes. The presence or absence of burrs was determined by visually observing burrs in the mold air vent.

[0014]

[Table 1]

From Table 1, the molding materials obtained in the respective examples have better fluidity than the conventional phenol resin molding materials of the comparative examples. It can be seen that burrs do not occur or are extremely small during molding.

[0016]

As is apparent from the above examples, the molding material of the present invention has excellent fluidity and has little or no burrs during molding, so that it can be widely used as a molding material having good moldability. It is possible.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a transfer molding die used in an example.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 Circular Cavity 2 Square Cavity 3,4,5 Air Vent 6 Pot 7 Plunger

Claims (2)

[Claims] 1. A thermosetting molding material containing a phenol compound containing a trinuclear or higher polynuclear phenol compound as a main component, a curing agent, and an organic or inorganic filler as a main component. 2. The thermosetting according to claim 1, wherein the polynuclear phenol compound is a polynuclear phenol compound alone or a mixture of two or more thereof, or a mixture with a binuclear phenol compound or a novolac type phenol resin. Molding material.