JPS61106630A - Production of thermosetting resin molding material - Google Patents

Abstract

PURPOSE:To obtain the titled granular material free of fine powder inexpensively in high yields, by mixing a granular thermosetting resin material containing fine powder with a lubricant having a m.p. in a specified range while heating the mixture in a specified range of temperature. CONSTITUTION:100pts.wt. granular thermosetting resin molding material containing 3-15wt% fine powder (prepared by grinding a product obtained by adding various additives to a base resin such as a phenolic resin, amino resin or polyester resin and kneading this mixture with heating and classifying the ground product) is mixed with 0.5-50pts.wt. at least one lubricant of a m.p. of 40-85 deg.C (e.g., stearic acid). Said mixing is performed in a temperature range of the m.p. of the lubricant to this m.p. + 20 deg.C. Because the fine powder can be agglomerated and granulated, dusting property and the dispersion of weight encountered in processing by a tabletting machine or an injection molding machine equipped with a volumetric feeder can be eliminated. In this way, a fine powder-free thermosetting granular material can be produced inexpensively and industrially in high yields.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a tablet molding machine, an injection molding machine, etc. equipped with a capacitive molding material metering device, which has excellent uniformity of weight from shot to shot and does not generate dust. The present invention relates to a method for producing a thermosetting resin molding material.

[Prior art]

Thermosetting resin molding materials such as phenolic resins, amino resins, polyester resins, diallyl phthalate resins, and epoxy resins have excellent heat resistance, electrical properties, mechanical strength,
Due to its excellent dimensional stability and good moldability, it is possible to obtain desired molded products at a relatively low cost, so it is widely used as a basic industrial material.

Conventionally, the manufacturing method for thermosetting resin molding materials involves mixing the base resin of the molding material with powdered raw materials such as curing agents, fillers, colorants, and other additives, and then heating the mixture with hot rolls or the like at 60 to 140°C. Generally, the plate-like or lump-like mixed material obtained by kneading in a container is pulverized after cooling, and then subjected to a sieving process to adjust the particle size to a granule material suitable for the intended molding method. ing.

In such a manufacturing method, even if coarse pulverization is performed and fine powder materials are removed in the sieving step, it is inevitable that about 2 to 10 pieces of fine powder material will be mixed into the granule material. Therefore, when handling the granular material, fine powder may be scattered and cause environmental pollution, which is not preferable.

In addition, although the granular material is uniformly mixed and packaged to prevent particle size classification, the large particle size material and the fine powder material may mix inside the packaging container due to the influence of vibrations during material handling such as transportation. May be classified. Granular materials classified in particle size in this way have uneven densities within the loft, resulting in the disadvantage that the weight of each shot is not constant in tablet molding machines and injection molding machines equipped with a capacitive measuring device. The problem is that it requires human labor to adjust the weight, which prevents automation from reaching its full potential.

On the other hand, pelleted materials manufactured using the extrusion granulation method have the advantage of ensuring uniformity of weight for each shot because the size of the material is constant and there is no fine powder. This method has lower productivity than the granular material method, which is manufactured through a roll mixing process and a pulverization process, so its uses are limited in terms of economy and marketability, and it is not a common method for manufacturing thermosetting resin molding materials.

In recent years, there has been remarkable development in electronics and automobiles↓ ・1 Miniaturization of parts in cutting-edge technology fields such as cars,
There is a need for the development of granular materials that can respond to the trend towards precision. In order to respond to such trends, there is a high demand for a manufacturing method that can accurately ensure weight uniformity and economically provide granular materials without scattering of fine powder on an industrial scale.

[Purpose of the invention]

The present invention solves the problems of dust generation and unstable needle accuracy due to the inability to completely remove fine powder in the conventional granule material production method, by producing a granule material without fine powder. As a result of research to find a method for manufacturing with high performance, we added a finely powdered lubricant with a melting point of 40 to 85°C to the granule material, and the granule material was heated in a temperature range exceeding the melting point of the lubricant and 20°C above the melting point. We obtained the knowledge that when mixed with a fine powder material while heating, the fine powder material is agglomerated into granules and the fine powder disappears.Based on this knowledge, we conducted various studies and completed the present invention.

[Structure of the invention]

The present invention provides a thermosetting resin molding material, which is characterized in that it is mixed with 100 parts by weight of a granular thermosetting resin molding material partially containing a fine powder material as a particle size component, while heating to a temperature below .degree. This is the manufacturing method.

The granular thermosetting resin molding material referred to here refers to paste resins such as phenol resins, amine resins, polyester resins, diallyl phthalate resins, and epoxy resins, as well as hardeners, fillers, colorants, mold release agents, and Powdered raw materials for other additives are mixed and kneaded in a mixing device such as a heated roll at 60 to 1.40°C.The mixed material in the form of a plate or lump is crushed and sieved according to the desired molding method. The particle size was adjusted through the separation process.

The particle size of the granular material is approximately 7-9 mesh, 9-10 mesh.
It consists of particle size components of 100 mesh 80 cm and 100 mesh pass 10 cm, and fine powder material of 100 mesh or more is mixed.

To 100 parts by weight of the granule material, 0.5 to 5.0 parts by weight of one type of fine powder lubricant having a melting point of 40 to 85° C. or 28 or more is added and mixed. The types of lubricants are as follows. C1
□~23 saturated fatty acids; lauric acid, palmitic acid, stearic acid, etc. C16-26 saturated alcohols: cetyl alcohol, stearyl alcohol, aracyl alcohol, ceryl alcohol, etc. Fatty acid amide; oleic acid amide, linoleic acid amide, linoleic acid amide, etc. Fatty acid ester; atearic acid monoglyceride, oleic acid monoglyceride, etc.

The optimum lubricant is a fine powder lubricant having a mesh pass of 95% or more in terms of dispersibility in the granule material.

Coarse particle size lubricants are not preferred because they have poor dispersibility in granular materials.

0.5 to 5.01 iL parts of one or more of the above-mentioned lubricants are added to 100 parts by weight of the granular material containing about 10% of the fine powder material of 100 messier passes, and mixed uniformly. In such a granular material, the lubricant is well adapted to the surface of the material particles. 200 to 400 kg/h of the granule material
When the lubricant is passed through a screw conveyor device at a feeding rate of The lubricant was melted by the thermal effect, and more than 100 meshes of fine powder material were agglomerated and granulated on the surface of the granule material, making it possible to produce a granule material free of fine powder.

If the heating cylinder is heated to a temperature of 90° C. or higher, the granule material will fuse and lose its shape, making it unsuitable for molding. Further, at a temperature below the melting point of the lubricant, the above-mentioned effect of aggregation and granulation of the fine powder material is not observed, and fine powder such as the initial amount of granule material remains.

In addition, in the present invention, the fine powder material of 100 mesh passes is 15%
In the following granule materials, the effect of agglomerating and granulating fine powder is high and the fine powder can be removed. However, if the amount of fine powder material is as large as 20 inches or more, the dispersibility of the lubricant will be impaired, so it is not suitable to remove the fine powder.

〔Effect of the invention〕

According to the production method of the present invention, fine powder can be agglomerated and granulated in a granule material containing 3 to 15% fine powder.As a result, the drawbacks of conventional granule materials, such as dust generation and the need for a capacitive metering device, can be achieved. It is suitable as a method for producing thermosetting resin granule material without fine particles economically and inexpensively, with a very high yield, and on an industrial scale, as it can solve the weight variation in tablet molding machines or injection molding machines. It is.

〔Example〕

Powder raw materials of 100 parts by weight of novolac type phenol resin, 15 parts by weight of hexahethylenetetramine, 73 parts by weight of wood flour, 26 parts by weight of calcium carbonate, 2 parts by weight of spirit black, and 4 parts by weight of stearic acid were mixed and kneaded with a heated roll. The resulting plate-shaped mixed material is pulverized using a final type pulverizer equipped with 61 screens. The particle size distribution of the molding material after crushing is 7-9 mesh 10 inches, 9-100 mesh 6 inches.
5%, 25 pieces per 100 meshes.

The molding material was sieved at a speed of 600 Da/H using a gyro sifter equipped with a 100 mesh screen.
The particle size was adjusted to 14.6% mesh pass granule material with less fine powder, and 100 parts by weight of this granule material was
When a mixture to which 1.2 parts by weight of powdered stearic acid of 75 msec or higher is passed through a heating cylinder whose temperature is controlled at 80°C at a supply rate of 300 kf/h, fine powder is deposited on plastic bags, hands, and clothes. A molding material that does not stick to dust or generate dust can be obtained.

The above granule material was continuously molded into 100 shots using a 433F breaker injection mold in an RJ 140C injection molding machine manufactured by Kojima Seisakusho, and the weight of each shot was measured. Minimum 443
1, with very little variation in molded product weight and less occurrence of flakes, with zero molding defects and 100% yield.
Obtained with. Next, the molded product could be easily finished with high efficiency using an automatic deflasher finishing machine manufactured by Shinto Kogyo ■ without any manual effort.

[Comparative example]

When the granular material containing 100 mesh black pass 14.6% described in the examples is charged into the molding machine hopper, fine powder scatters and adheres to hands, clothes, and equipment around the molding machine, which is unfavorable in terms of environmental hygiene. Furthermore, when the granule material was continuously molded for 100 shots using the breaker injection molding tool described in the examples, the weight variation of the molded products was 447 mm at maximum. , the minimum is 4402, which is a large number.
There were 7 shot defects and the yield was low at 93%. Some of the good molded products had thick particles, and since the particles could not be removed by the deflasher finishing machine alone at the Shinto Plant, manual refinishing was required, resulting in inefficiencies in both molding and finishing.

Claims (1)

[Claims] Granular thermosetting resin molding material 1 containing 3-15% fine powder
A mixed material of 0.00 parts by weight and 0.5 to 5.0 parts by weight of one or more lubricants having a melting point of 40 to 85°C is heated above the melting point of the lubricant in a temperature range from the melting point to 20°C. A method for producing a thermosetting resin molding material, characterized by mixing the material while mixing.