JPS60144354A - Phenolic resin composition - Google Patents

Abstract

PURPOSE:To obtain a phenolic resin composition having excellent mechanical strength, electrical properties, and moldability, suitable for electrical parts, etc., by adding organic natural fiber obtained by grinding a cotton fabric such as knitted goods to a phenolic resin, followed by compounding in a dry process. CONSTITUTION:A cotton fabric such as knitted goods, crepe, or denim is ground to prepare organic natural fiber of 3mm. or less in length. Into a resol-type or a novolak-type phenolic resin are incorporated 5-20wt% organic natural fiber prepared above, and preferably in addition, fillers such as wood flour, calcium carbonate, or clay, which are then dry-compounded using rolls, an extruder, etc. to give the objective phenolic resin composition. The obtained composition can be easily molded by any usual molding process such as compression, transfer or injection molding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses organic natural fibers with a fiber length of 3 mm or less obtained by crushing cotton fabrics such as stockinette, crepe, and denim into resol or novolac type phenolic resin. This invention relates to a phenolic resin molding material characterized in that it is manufactured by a dry process using a roll, an extruder, etc. by blending 20 parts by weight.

Conventionally, phenolic resin molding materials have been widely used as insulating materials with a good balance of moldability, quality, cost, etc., for electrical parts in the field of heavy electrical or light electrical equipment.

However, as parts become smaller and thinner reflecting the recent trends in resource and energy conservation, improvements in materials, particularly in mechanical strength, are being sought. It has been known that 711 has improved mechanical strength when mixed with glass fibers, cloth strips, organic fibers, etc. However, materials containing glass fibers have problems with wear of molds, screws, cylinders, etc. In the case of cloth strips, the dry method does not work well in producing the material, so the wet method is used to produce the material, but the resulting material has problems with formability and dimensional stability.

Furthermore, in the case of organic fibers, long fibers with a large aspect ratio are used in order to enhance the reinforcing effect, so when produced by a dry process, there is a problem with the uniform dispersion of the fibers in the material. Therefore, problems arise in terms of characteristics, such as insufficient reinforcing effect and a drop in electrical characteristics. In addition, materials manufactured using the dry method using long B-fibers have a low bulk density, which means they are bulky, so there may be problems such as hopper bridges or charge variations during injection molding.
In view of this situation, in order to improve the mechanical strength while maintaining the characteristics of the materials conventionally used in the above-mentioned fields, the present invention was developed as a result of intensive study. It is complete.

The invention will be described in detail below.

Since the phenolic resin used is manufactured by a dry method, any novolak or resol can be used as long as it is solid at room temperature.

The softening point of the resin is preferably 60 to 100°C from the viewpoint of ease of handling and stability during production. The organic natural fibers to be used can be one type or a combination of two or more fibers, as long as they are completely crushed and have a fiber length of 3 or less, such as cotton fabrics, such as crepe, stockinette, and denim. . Is the fiber length 3mm? If it exceeds c, the fibers will not be sufficiently defibrated during production and will not be uniformly dispersed in the material, resulting in insufficient machining strength and electrical properties. In some cases, molding problems may occur.

The properties of the reinforcing material that can be used in the dry method are that it has good dispersibility during melt-kneading, that the bulk density does not become extremely small when made into a material, that the reinforcing effect is sufficiently expressed, and that the cost is low. The key point is things like that.

Fibers used as reinforcing materials include, in addition to those of the present invention, synthetic fibers such as nylon, vinylon, and tetron, hemp, silk, wool,
There are natural fibers such as pulp, but they do not meet the above requirements, so #1 cannot be used. Also, raw cotton/e
Similarly, those called lupus, defibration, and lubrication do not have good dispersibility and cannot provide sufficient mechanical strength.

In addition, if the blending amount is less than 5 weight percent, there is no effect at all, and if it exceeds 20% by weight, the bulk density of the material becomes extremely small.
Because the dispersibility of fibers in the material deteriorates, cows cannot be used as a material.

Therefore, the blending amount is desirably 5 to 20 cm.

Also, as a filler, wood flour, phenol 1? j Organic fillers such as crushed boards or melamine laminates, and 25-40% of the total amount by combining one or more of two or more fillers such as calcium carbonate, clay, talc, asbestos, etc.
It is preferable to mix the M amount (%) according to the required performance.

The phenolic resin molding material obtained as described above is molded by heating and pressurizing it by a commonly used molding method such as compression molding, transfer molding, or injection molding. Since the type, length, and amount of fibers contained in this phenolic resin molding material are regulated, molded products with good moldability and excellent mechanical strength can be produced without compromising conventional properties. It is something that can be obtained. Examples are shown below.

(Example 1) An addition combination reaction of formalin and phenol at a molar ratio of CF/P (F: formaldehyde, P: phenol) of 0.80 using hydrochloric acid as a catalyst according to a conventional method. conduct softening point 90
°C no? I got rack resin. 45 pieces of this resin, 15 pieces of cotton fiber with a fiber length of 0.51 m obtained by crushing stockinette, 20 pieces of wood flour, 8 weight% of clay,
7% by weight of hexamethylenetetramine, 300% by weight of a curing accelerator, 1% by weight of a mold release agent, and 1% by weight of a colorant were mixed and kneaded with hot rolls to obtain a molding material.

(Example 2) Resol PR manufactured by Sumitomo Durez ■ R-5114150'f
Jj material, 20 layers of cotton fiber with a fiber length of 1 obtained by crushing crepe, 25 weights of calcium carbonate powder, 3 parts of curing accelerator, mold release agent IM Keiichi, coloring agent 1-@f ,) were mixed and kneaded using an extruder to obtain a molding material.

(Example 3) An addition condensation reaction was carried out in accordance with a conventional method using 7-euric acid as a catalyst at a total molar ratio of formalin and phenol of 0.85 to obtain q of nobilacrenone with a softening point of 96°C.

This resin was sweetened 48 times, and the denim was completely crushed to obtain a cotton fiber with a fiber length of 0.7 mm. .L
Section, hexamethylenetetramine 7 Vinegar section, curing accelerator 3
Moon [Dochi, mold release agent 1% by weight, Yoshiiroha IJ 1], t:
Mix the metal and knead it in an extruder to make the molding material (!1).

(Comparative Example 1) Novolak 45Nr-F+', % same as Example 1 with 4 fruits
, Side line of fiber length 0.5 mm obtained by crushing stockinette: 25] 1 part of a mold release agent and 1% by weight of a coloring agent were mixed and kneaded with a hot roll to obtain a molding material.

(Comparative Example 2) The same resin multi-layer type layer as in Example 2, cotton fiber obtained by crushing crepe with a fiber length of 6 mm, fiber 20 weight 11 calcium carbonate powder 25 weight weight, curing accelerator 3N amount, One part of a mold release agent and 1% by weight of a colorant were mixed and kneaded using an extruder to obtain a molding material.

Complete Table I of evaluation results for molded products molded according to conventional methods
K, showed. It can be seen that the molding material obtained according to the present invention has excellent electrical properties and mechanical properties.

Note 1) Based on soft X-ray observation 2) Injection moldability, Toshiba IR-80. Evaluated using JIS family mold. (Hora・Gubrifuji. Evaluated from charge variation) ○: Both have no problem △: Charge cracking exists ×: Both have gaps 3) Other custom-made HJ Is l (69111fC Yoru. (Test piece (・Made by injection molding) ) Patent applicant Sumitomo Bakelite Co., Ltd.

Claims (1)

[Claims] Organic natural fibers with a fiber length of 3 or less obtained by crushing cotton fabrics such as stockinette, crepe, denim, etc.
A phenolic resin composition characterized in that it is produced by a dry process with a 20-layer compound.