JPS5825571B2 - Netsukou Kaseiji Yushisei Keizai Ryouno Seizouhouhou - Google Patents

Description

Detailed Description of the Invention The present invention relates to a method for producing a thermosetting resin molding material, and an object of the present invention is to provide a method for producing a spherical molding material that can stably supply the material from an injection molding machine hopper into a cylinder. be.

Currently, thermosetting resin molding materials that can be stably molded using in-line injection molding machines, which are common injection molding machines for thermosetting resins, include phenolic resin molding materials, alkyd resin molding materials, and diallyl phthalate resin molding materials. There are materials etc.

To perform stable continuous molding with an inline injection molding machine,
It is necessary that the material is stable within the cylinder and that the material can be stably supplied into the cylinder from the hopper of the injection molding machine.

Therefore, the shape of the molding material is generally a powder with a constant particle size.

In order to handle the non-molded material and to obtain uniform supply into the cylinder, it is desirable that the material has a small amount of fine powder and a small particle size distribution, and the optimal shape of the material is a spherical shape with a constant particle size.

There are various granulation methods for forming materials into a certain shape, such as a method using an extruder and a method of granulation using a high-speed stirrer such as a Henschel mixer, but each method has a limited composition.

In addition, when using a crushing method using a hammer mill, etc., if long fibers such as vinylon, glass fiber, or asbestos fiber are used as a filler, the bulk of the molding material increases, making it impossible to stably supply the material from the hopper into the cylinder. Injection molding becomes impossible.

In addition, pulverization causes severe cutting and separation of fibers, which causes a decrease in strength.

Furthermore, it is difficult to crush a molding material using a resin with a low softening point due to the frictional heat of the crusher.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a spherical molding material, which eliminates the conventional drawbacks and allows stable and continuous molding of materials of any composition.

In the present invention, a molding material composition is mixed with a kneader, a roll, etc. to create a uniform composition, which is formed into a sheet and then cut to make a pellet.

To this pellet, 0.2 to 1.0% by weight of fine powder with a particle size of 0.2μ or less and a melting point of 90°C or higher is added to the pellet,
1000 to 300 with a high-speed stirrer such as a Henschel mixer.
In this method, a spherical molding material is obtained by stirring at 0 pm for 5 to 10 minutes.

This will be explained in detail below.

The molding material composition that can be used in the present invention can be applied to general molding material compositions such as phenolic resin molding materials, shea I) phthalate resin molding materials, and alkyd resin molding materials.
In particular, as a filler, use fibers of 31rLrfL or higher, such as vinylon fibers, glass fibers, asbestos fibers, etc.
The effect is particularly exhibited when granulating materials having a composition containing % or more and a composition in which the softening point of the resin used is 80° C. or less.

Conventional kneader mixing, roll mixing, co-kneader mixing, etc. can be applied to the mixing of the molding material composition, and in the case of easily cuttable fibers such as glass fibers, wet kneader mixing is preferable.

The molding material composition mixed in the above method is heated to a temperature of 70 to 90°C.
Roll it into a sheet with a thickness of 2 to 5 mm, and cut it with a pelletizer or the like to make pellets of 2 to 51 rLm square.

Next, 0.2 to 1.0% of fine powder with a particle size of 0.2μ or less and a melting point of 90°C or more is added to the pellet,
A spherical molding material is obtained by stirring for 5 to 10 minutes at a rotation speed of 1,000 to 3,000 pm using a high-speed stirrer such as a Henschel mixer.

At this time, the temperature of the high speed stirrer must be below the softening point of the material.

The fine powder used in the present invention has a particle size of 0.2 μm or less, preferably 0.01 μm or less, and a melting point of 90° C. or higher, preferably 90° C. or higher and 160° C. or lower.

If the particle size is too large, the dispersion becomes non-uniform, resulting in blockage during rotation of the high-speed stirrer, or deterioration of the appearance and properties of the molded product.

Next, if the melting point of the fine powder is too low, it will melt before it is evenly dispersed on the material surface due to the frictional heat caused by high-speed rotation, and the powder will not be uniform (this will deteriorate the appearance of the molded product).

Furthermore, when the appearance of the molded product is important or when the amount added is large, a melting point of 90°C to 160°C is optimal.

Such fine powders include zinc stearate, magnesium stearate, calcium stearate, aluminum stearate, finely divided calcium carbonate, finely divided silica, and the like.

Next, the amount of fine powder is preferably 0.2 to 1.0%, particularly 0.3 to 0.5%, based on the pellet.

If the amount of fine powder is small, it will easily block during high-speed rotation (too much will deteriorate the appearance and other properties).

The molding material obtained by this method can be used not only for injection molding, but also for transfer molding and compression molding.

The present invention will be specifically explained below based on examples.

Example 1 24 parts of a low softening point polyester resin with a softening point of 80°C, 4 parts of diallyl phthalate monomer, 0.6 parts of dicumyl peroxide, 14 parts of glass fiber with a length of 1O-fIL7IL, 12 parts of calcium carbonate, hydrated alumina 40 parts at 80℃
The resulting alkyd molding material mixture was mixed for 20 minutes at a temperature of 60°C to a thickness of 5 m1 using a roll.
Make it into a 1L sheet and use a pelletizer to make it into a 5m sheet.
Forming m-square pellets 3. To the pellets, 0.3% zinc stearate was added and stirred in a water-cooled Henschel mixer at a rotational speed of 300 rpm for 5 minutes to obtain a spherical alkyd molding material.

This material has a stable supply of material from the hopper into the cylinder.
Excellent continuous moldability.

The injection molding conditions are shown in Table 1, and the obtained properties are shown in Table 2.

As a reference example, when the sheet obtained with the above roll was pulverized using a hammer mill type pulverizer with a screen of 8 ψ, it was impossible to pulverize it because of the low softening point resin.

Example 2 50 parts of novolak resin, 75 parts of hexamine, 1.3 parts of zinc stearate, 2 parts of slaked lime, 18 parts of wood flour, 9.6 parts of asbestos, 10 parts of vinylon having a length of 3T/L1n, 1 part of spirit black, 2 parts of furfural are uniformly mixed in a blender, rolled for 7 minutes with a front roll at 90°C and a rear roll at 80°C, and immediately made into 5 mm square pellets using a pelletizer.

0.3% zinc stearate was added to the pellets, and the mixture was mixed with a Henschel mixer at 200 rpm 5.
After stirring for a minute, a granular injection phenolic molding material with high impact strength of vinylon filler was obtained.

The molding material obtained by the above method is Meiki Seisakusho RJ-75
Continuous molding is possible at A.

According to the present invention, it has become possible to easily obtain granular molding materials from long fiber-containing thermosetting resin compositions and low softening point thermosetting resin acids, which were conventionally difficult to granulate.

Note that the present invention is not limited to the above-mentioned thermosetting resin composition, and it goes without saying that a granular molding material can also be obtained from an ordinary thermosetting resin composition.

Claims (1)

[Claims] 1 Add fillers and other additives to thermosetting resin,
After kneading into a sheet, cut it into pellets and give it a melting point of 9.
A method for producing a thermosetting resin molding material, which comprises adding fine powder having a particle size of 0.2 μm or less at a temperature of 0° C. or higher, and stirring and granulating the mixture with a high-speed stirrer.