JPS608204B2 - Manufacturing method of phenolic resin molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a phenolic resin molding material through injection molding.

The purpose is to obtain a phenolic resin molding material for injection molding that has stable and constant molding processability and quality in injection molding. In recent years, injection molding has attracted attention for thermosetting resin phenolic resin molding materials because it has a faster molding cycle than conventional compression molding or transfer molding, is easier to automate, and can be molded with high efficiency, and is widely used. It has been put into practical use in the field and is used to streamline molding.

In order to maximize the effects of high-speed automation through injection molding and to consistently obtain products with stable quality, the injection amount, appearance, and molded product rigidity must be constant for each cycle. To achieve this, there is no fluctuation in the fluidity of the material at each stage of the injection molding process, such as metering plasticization, in-mold injection filling, and in-mold hardening, and even in long-term continuous molding, there is no change in material lot. There is also a need for a molding material with uniform fluidity that exhibits stable injection moldability under exactly the same molding conditions and does not require manual changes in molding conditions, and such a molding material has been highly desired.

Phenol resin molding materials include phenol resin, curing agent,
It is obtained by blending fillers, mold release agents, pigments, additives, etc., and adjusting fluidity in the heat-kneading process.

In particular, the moisture content of fillers used on a daily basis is not controlled, and therefore varies depending on the type, production area, manufacturing time, storage conditions, and seasonal fluctuations. Therefore, in order to obtain material flowability that is suitable for injection molding, manufacturing conditions have to be changed. When a certain level of fluidity is imparted by changing the kneading conditions, the quality will vary depending on the degree of kneading of the material, causing variations in quality depending on the material lot. In addition, materials produced under constant cross-wire conditions and with the same material kneading level have the disadvantage that fluid hardenability and other qualities change depending on the water content of the filler. If there is too much moisture, a lot of gas is generated during injection molding, which tends to cause poor appearance, and if the moisture is too little, the curing reaction will be accelerated, resulting in insufficient thermal stability in the cylinder and unstable molding. With conventional fillers, it is difficult to obtain a phenolic material for injection that has uniform flow hardening properties and uniform quality, and there are limits to highly efficient high-speed automatic molding in injection molding.

The present invention aims to solve these drawbacks, and by controlling the moisture content of the filler, which is a raw material, to a constant level using air or humidity-controlled air, it is possible to most effectively achieve both flow hardening properties and quality. I discovered that.

As a result, the molding processability and quality during injection molding became constant and uniform, and the objective was achieved. The main types of powder fillers that can be generally used include organic ones such as wood flour and pulp, and inorganic ones such as frog earth, clay, alumina, calcium carbonate, and asbestos. For example, as a conventional method for controlling the moisture content of powder raw materials,
JP-A-585, JP-A-48-28557, JP-A-50-183460, etc. are known. All of them are aimed at efficiently drying powder and granular materials. In contrast, the purpose of the present invention is to obtain a phenolic resin molding material with excellent moldability and stable quality by containing a certain amount of moisture in raw materials and controlling the temperature, and such techniques are completely unknown. It wasn't. We considered how to economically control the moisture content of the filler, which affects moldability and quality, on an industrial scale, and designed the raw material storage tank to have a fluidization mixer structure with a humidity control device. After uniformly mixing the filler with humidity-controlled air to make the moisture content of the filler constant, it is used as a raw material for the composition in the formulation, making it possible to uniformly adjust the fluidity in the manufacturing process, and making it easier to use during injection molding. It has been confirmed that a phenolic resin molding material with constant moldability and quality can be obtained, and has been completed as a manufacturing method that can achieve the objective in an extremely rational manner.

In the present invention, powder filler used as a raw material for phenolic resin molding materials for injection molding is stored in a storage tank having the structure and function of a fluidization mixer with a humidity control device, and is fluidized by air or humidity control air to uniformly distribute the powder filler. This is a method for producing a phenolic resin molding material for injection molding, which is obtained by adjusting the moisture content of the filler to a constant level, and then using it as a raw material for formulation through a production process of heating and kneading.

In the present invention, raw materials are powdered fillers used in phenolic resin molding materials for injection molding, including organic powders such as wood flour, pulp, walnut flour, rice flour, and oak flour, alumina, calcium carbonate, Calcium sulfate “magnesite,
It is made of one or a combination of two or more of inorganic powders such as mica, clay, kaolin, talc, asbestos, kakarite powder, keishi powder, and glass.

As shown in the figure, an example of a fluidization mixer used in the present invention is as follows: "Raw material 2 is introduced from a raw material input row, and humidity-controlled air is passed through a perforated plate 4 from a humidity-controlled air inlet 3 into the raw material 2. Fluidization and mixing is performed with blown and humidity-controlled air, and unnecessary air is discharged from the air outlet 5 and the moisture measuring device 6
This is a device that can measure moisture in raw materials and stabilize the moisture in raw materials.

By the manufacturing method of the present invention, a stable and uniform heating and mixing state can be obtained in the material manufacturing process, fluidity adjustment is easy, and there is no need to adjust heating and kneading conditions for each lot. A uniform molding material with the same flow hardening behavior without any variation can be obtained.The injection moldability of the molding material obtained by the production method of the present invention is good, and the moldability L quality changes with each molding shot. There are no differences in molding processability or quality from lot to lot, and extremely stable injection molding is possible with continuous automation.The manufacturing method of the present invention allows for storage of raw materials, uniform mixing, and moisture adjustment at the same time. Therefore, compared to the conventional method, the overall equipment space is required, the mixing time is shortened, and the man-hours such as weighing and management of each raw material lot packaging unit are eliminated, and products of stable quality can be obtained without labor. The present invention has a great effect of streamlining the production process and is highly economical on an industrial scale.

Comparative Example Powder filler raw materials, wood flour, calcium carbonate, and clay were each randomly selected in 2 packs by manual packaging, and 10
0oo-moisture content (hereinafter simply referred to as moisture) measured by heat measurement is a maximum of 13.4% and a minimum of 4.3% for wood flour.
, maximum 1.6% and minimum 0.1% for calcium carbonate
, the highest was 3.4% and the lowest was 0.2% for clay.

Parts by weight of novolak resin 10 (hereinafter simply referred to as parts),
To a mixture of 15 parts of hexane, 4 parts of stearic acid, 4 parts of spirit black, and 4 parts of furfural, add 7 parts of wood powder of 2 lotuses selected above, 3 parts of calcium carbonate, and 1 part of clay to 14 parts. P○ichi 85℃. Heat and knead in a bowl for 20 minutes.
It was used as a lot molding material. During this heating and kneading, the rolling time for fluidity adjustment was 3 to 6 minutes. For this molding material, a mold temperature of 175 oo,
A 100-shot continuous molding test was conducted under constant molding conditions: curing time of 50 seconds, injection pressure of 1450k9/base, and injection time of 7 seconds, and all molded products obtained were visually inspected to ensure that there were no voids in the fillability and appearance of each shot. The surface of the molded product must be smooth and glossy, and No. 935 Barcol hardness tester shows that the sand released from the mold is 1, and the rigidity of the molded product is 2.
It was determined that the value was 5 or more, and the overall rate of good products relative to the total number of moldings was expressed as moldability.

The molding processability of these 20 lots of molding material showed the highest value.

The number of good shots out of 100 molding shots is 1.
00%, and the lot showing the lowest value was 45 good shots out of 100 molding shots, which was 45%, and the variation between lots was large. Similar molding tests were conducted in the following examples, and the moldability was simply expressed as a percentage. Example 1 The entire amount of wood flour from the second oven selected in the comparative example was put into a fluidization mixer and fluidized and mixed for 4 hours in controlled humidity air of 24% to 55%.

The moisture content measured by dividing the treated wood flour into two layers was at most 7.
1% minimum was 6.5%. To a mixture of 10 parts of novolac resin, 15 parts of hexa, 30 parts of calcium carbonate, 1 part of clay, 4 parts of stearic acid, 4 parts of spirit black, and 4 parts of furfural, 20 parts of the wood flour divided after the above humidity conditioning treatment was added. 7 types were added to the mixture, and 20 lots of molding material were prepared by heating and kneading with 140-0-8500 rolls. During this heat kneading, the oil time for fluidity adjustment is 4 to 4. It was powder. For these 20 lots of molding materials, the molding processability during injection molding was 100% at the highest and 97% at the lowest.
Example 2 The entire amount of calcium carbonate and clay selected in Comparative Example 2 were also put into a fluidization mixing tank and heated to 2400 ml.
- Fluidized and mixed in 35% humidified air for 4 hours. After treatment, each was divided into 2 parts and the moisture content measured was 0.3% maximum for calcium carbonate and 0.1% minimum for clay, 0.3% maximum for clay. 5% and the lowest was 0.2%.

A mixture of 10 parts of novolac resin, 15 parts of hexane, 4 parts of stearic acid, 4 parts of spirit black, and 4 parts of furfural, 3 parts of calcium carbonate, 1 part of clay, divided by the above fluidized mixture and humidity control, Then, 7 grains of wood flour, which had been fluidized, mixed and humidity-controlled in Example 1, were added and kneaded by heating with a roll at 140° C.-85q0 to obtain a molding material for a two-night bell. During this heating and kneading, the rolling time was kept constant at 4 minutes, and the same fluidity was obtained without any conditional adjustment. The molding processability of this two-sided lotus was 100% at maximum and 99% at minimum.

[Brief explanation of the drawing]

The drawing is a schematic diagram of a storage tank equipped with the function of a fluidization mixer with a humidity control device used in the present invention. Explanation of symbols, 1... Raw material input port, 2... Raw material, 3... Overflow air inlet, 4... Perforated plate, '5
... Air outlet, 6 ... Moisture measuring device, 7.
...damper, 8...raw material outlet.

Claims (1)

[Claims] 1. A method for producing a phenolic resin molding material for injection molding, characterized by fluidizing and mixing raw materials with humidity-controlled air and controlling the moisture content to a constant level.