JPH0768539A - Blending of additives for resin - Google Patents

Abstract

PURPOSE:To knead and granulate a resin and additives therefor while reducing the clogging of a screen mesh. CONSTITUTION:In blending additives for a resin with the resin, the additives for the resin are preliminarily compounded with a lubricant and mechanical shearing is applied to the obtained compound at a high speed to grind and mix the compound. This compound is blended with the resin to prepare a resin blend which is, in turn, kneaded and granulated by an extruder.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of kneading and granulating a resin and an additive for a resin by an extruder, in which the screen mesh is extremely free from clogging and the phenomenon of venting up of the resin is small and dust in the resin is small. And a method for effectively eliminating foreign matter.

[0002]

2. Description of the Related Art Conventionally, as a method of efficiently dispersing a resin additive in a resin, a lubricant is blended with the resin additive to improve dispersibility by improving the miscibility of the resin additive with the resin. There are known ways to raise it. For example, in Japanese Unexamined Patent Publication No. 54-50060, a surface of a molded product is prepared by blending an organic flame retardant such as decabromodiphenyl ether and a fatty acid metal salt, which are ground and uniformly mixed, with a resin. The method of significantly improving the appearance of the above is disclosed, and a preferable mixing method of the organic additive is disclosed.

The lubricity of the lubricant is to alleviate the frictional force between the polymers ("Practical Handbook of Additives for Plastics and Rubber", page 945, Chemical Industry Co., Ltd.). It is believed that the dispersion of However, when the particle size of the resin additive is relatively large, particularly when it does not melt at the processing temperature of the resin such as an inorganic compound, the particle size is retained as it is, so that clogging of the screen mesh or resin In addition to inducing the vent-up, etc., there is a problem that the discharge amount of the resin is reduced and the productivity is lowered.

As a method for preventing this, there is a method in which such an additive for resin is finely pulverized in advance and then added to the resin. In this case as well, static electricity generated during pulverization causes reaggregation of particles. Occurs, the particle size distribution is broadened, and the intended purpose is not achieved.

[0005]

In view of the above circumstances, when a resin additive having a relatively large particle size, particularly a resin additive that does not melt at the resin processing temperature is blended with the resin and extruded and kneaded, It is an object of the present invention to find a method that does not cause clogging of the screen mesh or bent up.

[0006]

Means for Solving the Problems As a result of studying a method for solving the above problems, the present inventors have found that the resin additive is not pulverized alone, but is preliminarily mixed with a lubricant and then pulverized. The present inventors have found that the resin additives can be prevented from agglomerating due to static electricity, and that homogeneous finely pulverized particles can be obtained with a relatively small amount of energy. That is, the present invention, in the method of blending the resin additive with the resin, after pre-blending the resin additive with the lubricant,
This is a method in which a crushed and mixed product is blended with a resin by adding a high-speed mechanical shear, and the mixture is kneaded and granulated by an extruder.

The present invention will be described in detail below. Resin additives in the present invention, lead stabilizers, organic tin stabilizers, antioxidants, stabilizers such as zeolite, titanium oxide, zinc oxide, pigments such as carbon black, calcium carbonate,
Typical examples thereof include fillers such as asbestos, mica, silica and clay, reinforcing agents, flame retardants such as antimony trioxide and red phosphorus. It is preferably applied to an additive that does not melt at the processing temperature of the resin. An inorganic compound is more preferable, and a stabilizer whose main component is zeolite is more preferable.

The resin in the present invention refers to all so-called thermoplastic resins. Specifically, polystyrene, acrylonitrile-styrene copolymers and their rubber reinforcements, acrylic resins, polyamides, polyesters, polyvinyl chloride, polycarbonates, polyoxymethylene,
Examples include, but are not limited to, polyarylates, polyphenylene ethers, polyphenylene sulfides, and the like. These rubber reinforcements, or blends of two or more kinds are also used.

[0009] Preferably, polystyrene, acrylonitrile-styrene copolymer and their rubber reinforcements, that is, high impact polystyrene (HIPS resin) and acrylonitrile-butadiene-styrene copolymer (A
A styrene resin such as a BS resin) is used.

As the lubricant in the present invention, hydrocarbon lubricants such as paraffin and low molecular weight polyethylene, fatty acid lubricants such as stearic acid, fatty acid amide lubricants such as styrene bis stearamide and ethylene bis stearamide, ester type lubricants. Lubricants, alcohol lubricants, metal soaps such as calcium stearate, zinc stearate, magnesium stearate, etc. are typically used. Preferred are fatty acid amide lubricants and metallic soaps.
Particularly preferred are ethylene bis stearamide and calcium stearate.

The mixing ratio of the resin additive and the lubricant can be set arbitrarily, but it is preferable that the weight ratio of the resin additive / the lubricant in the lubricant is 5% by weight or more.
When the amount of the lubricant is less than 5% by weight, the effect of preventing the additive from aggregating due to static electricity during pulverization decreases.

In the present invention, a general crusher is used as a method for adding high-speed mechanical shear. Specifically, a Henschel mixer, jet mill, roller mill, ball mill, spike mill, vibration mill, etc. are typically used. Particularly, a system having both a crushing action and a mixing action is preferable, and for example, a Henschel mixer is preferably used.

The extruder used in the present invention is not particularly limited, but specifically, a single-screw extruder, 2
Axial extruder, elastic melt extruder, sheet extruder,
Typical examples include a hydrodynamic extruder, a ram type continuous extruder, a roll type extruder and a gear type extruder.

[0014]

EXAMPLES The method of the present invention will be described below with reference to examples (hereinafter, “part” means “part by weight”).

Example 1 125 kg of a stabilizer composition comprising 70% by weight of sodium-type zeolite and 30% by weight of hydrotalcite and 125 kg of ethylenebisstearoamide were put into a 1000 l Henschel mixer, and the rotation speed was 280 rpm for 1 minute. ,
It was crushed and mixed. This is designated Stabilizer Mixture A.

This stabilizer mixture A was mixed with 100 parts of ABS resin (20 parts of butadiene component, 24 parts of acrylonitrile component, 56 parts of styrene component) in a co-direction twin-screw extruder having a screw diameter of 87 mmφ at a ratio of 1 part. It was fed in a system different from that for kneading and granulation. At this time, between the tip of the extruder and the die, 50, 150, 100, 50 are placed in order from the die side.
The screen mesh of the mesh was attached in combination.

The cylinder temperature of the extruder was 220 ° C., the discharge rate was 200 kg / hour, and the screw rotation speed was 100 rpm. The operation was extremely smooth, clogging of the screen mesh and venting were extremely small, and continuous operation was possible for 8 hours.

COMPARATIVE EXAMPLE 1 Extrusion operation was carried out in the same manner as in Example 1 except that ethylene bisstearamide was not used but the stabilizer was pulverized and mixed.
It was necessary to replace the screen mesh and clean the vent and die every hour. At this time, the screen mesh was clogged with a large amount of zeolite.

Example 2 Extrusion operation was carried out in the same manner as in Example 1 except that calcium stearate was used instead of ethylene bis stearamide in Example 1. The operation was extremely smooth and could be continuously operated for 8 hours.

Comparative Example 2 An extrusion operation was carried out in the same manner as in Example 1 except that the stabilizer mixture A was prepared by using a drum blender instead of the Henschel mixer, and the vent up was severe. It was necessary to replace the screen mesh and wash the vent and die every 3 hours. At this time, the screen mesh was clogged with a large amount of zeolite.

[0021]

According to the method of the present invention, the screen mesh is extremely free from clogging and the resin is hardly bent up, so that continuous extrusion for a long time becomes possible.

Claims (3)

[Claims] 1. A method of blending an additive for a resin with a resin, which comprises blending the additive for a resin with a lubricant in advance and then adding a high-speed mechanical shear to blend the pulverized mixture with the resin and extruding. A method of kneading and granulating with a machine. 2. The method according to claim 1, wherein the main component of the resin additive is an inorganic compound. 3. The method according to claim 1, wherein the lubricant is ethylene bis stearamide and / or calcium stearate.