JPS5838086B2 - Method and device for attaching additives to synthetic resin powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to uniformly and firmly adhering additives to the surface of synthetic resin powder.

Mixing various additives with synthetic resin powder and adhering the additives to the surface of the powder is widely practiced, but the conventional method of simply stirring and mixing the powder and additives at room temperature does not Additives cannot be firmly adhered to the surface of the powder or granules, and additives tend to fall off or separate.

Therefore, in order to uniformly and firmly adhere the additive to the surface of the powder or granular material, methods have been proposed, such as methods of adhering via a spreading agent, methods of heating during stirring and mixing, etc., but each method has its advantages and disadvantages. , not necessarily in a satisfactory manner.

Therefore, the main purpose of the present invention is to provide an excellent method for uniformly and firmly adhering additives to the surface of powder or granules.

To achieve the above object, the present invention employs the following method and apparatus.

That is,: (1) In the method of uniformly mixing and adhering additives to a synthetic resin powder, the heated synthetic resin powder and a heat-melting powder additive are mixed, and the heated synthetic resin It consists of dispersing the granular material and the additive by colliding with an obstacle in space, and stirring and mixing the mixture of the synthetic resin granular material and the additive that collided with the obstacle and dispersed. A method for attaching an additive to a synthetic resin powder, (2) a synthetic resin powder supply pipe, an additive supply pipe, a mixing tank in which the two supply pipes communicate, and the supply in the mixing tank. A rotating obstacle provided in the space below the supply port from the pipe, an agitating mixer provided in the mixing tank below the rotating obstacle, and a mixing agitation layer consisting of synthetic resin powder and additives. A device for adhering the additive to the synthetic resin powder is employed, comprising a mechanism for controlling the upper surface of the synthetic resin powder to be maintained below the rotational obstacle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

The heated synthetic resin powder is supplied into the mixing tank 3 through the synthetic resin powder supply pipe 1, and the powder collides with an obstacle, such as a rotating obstacle 4 as shown in the drawing, and is scattered. The mixture is dispersed and falls into the mixing tank 3.

On the other hand, the thermoplastic powdered additive supplied into the mixing tank 3 via the additive supply pipe 2 also hits an obstacle such as the above-mentioned rotating obstacle 4, scatters, and is dispersed into the mixing tank 3. being hit and falling.

The synthetic resin powder supplied to the mixing tank 3 must not be heated to such a high temperature that melting will occur, but on the other hand, it must be heated to such a degree that at least a portion of the additive that has come into contact with the powder can be melted. It is necessary that the

Further, the additive may be one that at least partially melts at a lower temperature than the powder or granular material, and for example, one containing heat-melting powder may be used.

In order to make the additive heat-fusible, it is also possible to use a mixture of two or more additives to utilize the melting point drop due to the mixing effect.

The powder supply pipe 1 and the additive supply pipe 2 for supplying the powder and additives may be connected to the mixing tank 3 through separate supply ports, or, as shown in the drawing, one pipe may be connected to the mixing tank 3. They may be connected through the same supply port after forming a supply pipe.

An obstacle, such as the rotating obstacle 4, is provided in the space in the direction in which the powder and additives supplied into the mixing tank 3 fall and move (that is, below the supply port).

The obstruction may be any object that can cause the powder or additives falling from the supply port to scatter in all directions and be dispersed in the mixing tank when it collides with the top surface, and may be a rotating obstruction. Preferably.

As shown in the drawing, examples of this rotational obstacle include a conical plate-shaped rotating object with a protrusion 5, a rotating disk-shaped object with a protrusion on the upper surface, and a rotating disk-shaped object with a turbine-type blade. Those with rotating perilla blades, or those with propeller-type blades that rotate are used.

In the rotating obstacle 4 in the form of a disc or cone plate having protrusions 5 on the upper surface, a plurality of protrusions 5 are provided on the surface on which the powder and granules and additives collide, that is, on the upper surface, so that the powder and granules and additives are distributed in all directions. It is necessary to uniformly disperse the particles, and the shape of the upper surface may be substantially disk-shaped or conical plate-shaped (it may be curved).

Further, the rotating obstruction, which is a turbine-type or propeller-type blade, must be rotating at a speed that allows the particles and additives falling from the supply port to collide with the blade.

Such a rotating obstacle must be rotating at a rotation speed of 100 rpm or more, and the residence time of the powder or additive on the rotating obstacle is 0.
The time is preferably 1 to 0.5 seconds in order to achieve uniform dispersion.

The mixture of granules and additives dispersed and fallen into the mixing tank 3 as described above is agitated and mixed by the stirring mixer 7 rotated by the stirring shaft 6 to become granules with additives attached thereto and discharged from the discharge port 11. be done.

While being stirred and mixed, the additive comes into contact with the powder and granules and melts and adheres to an appropriate degree, and at the same time, the excessively melted additive is wiped off and adheres to the surface of the resin powder.

It is then cooled and adheres firmly and uniformly to the surface of the powder.

This stirring and mixing is performed at a speed of 100 rpm or more, and at a speed of 6
It is preferable to carry out the application for 0 seconds or more from the viewpoint of uniform adhesion.

If this stirring and mixing is insufficient, the molten additives will cause the powder and granules to stick together and form lumps, and
It is difficult to ensure sufficient and uniform adhesion of additives.

In order to ensure sufficient dispersion by the rotating obstacle 4,
It is necessary that this rotational obstacle 4 (particularly its upper surface) is not immersed in the layer 8 of the mixture of powder and additive.

For this purpose, a mechanism 10 for controlling the position of the upper surface 9 of the mixture layer 8 is provided.

The mechanism includes a device that changes the supply amount and discharge amount by detecting the liquid level, or a mechanism that maintains the supply amount and discharge amount at an amount that keeps the upper surface 9 constant.

The method of the present invention can be widely used when adhering and mixing powder additives to synthetic resins in the form of powder or granules such as pellets.

Moreover, since the additives can be attached and mixed in a simple manner, the additives can be continuously attached and mixed by supplying the heated pellets as they are.

In the additive-adhered powder obtained by the method of the present invention, the additive is uniformly and firmly adhered to the surface of the powder.

Therefore, it is possible to prevent the additive from falling off from the powder or granular material due to physical distribution operations such as air blowing and vibration.

Example A vertical cylindrical vertical continuous mixing tank with an inner diameter of 500 mm and a length of 1000 mm was heated to 90° C. with a diameter of 3.0 mm. Om
iL of nylon 66 pellets at a feed rate of 30 kg/min and 30% stearic acid melting at 90 °C.
The sulfur stearic acid/aluminum stearate mixture was fed at a feed rate of 200 f/min.

In the mixing tank, a conical plate-shaped rotating obstacle having a protrusion on the upper surface and a stirring mixer were installed on the same stirring shaft which rotated at 1 2 O rpm.

The supplied powder and granules and additives collided with the above-mentioned rotating obstacle, and the liquid that remained on the rotating obstacle for 0.3 to 0.5 seconds was dispersed and fell, and after being stirred and mixed for 90 seconds, it was discharged.

The resulting pellets with additives were continuously sampled every 5 minutes for 30 minutes and analyzed, and the amount of additives attached was 0.67±0.02%.
When observed under a microscope with a magnification of 00x, the additive was found to be uniformly adhered to the surface.

Furthermore, a vibrating sieve with a mesh size of 30
Even after sieving for minutes, the additive did not fall out.

On the other hand, when stirring and mixing was carried out under the same conditions except that the rotational obstruction in the apparatus was removed, it was found that the additive was unevenly distributed and adhered to the pellet surface by observing the pellet surface under a 100x microscope.

Furthermore, when pellets and additives were treated with the above apparatus at room temperature of 25°C under the same conditions except for the pellet temperature conditions, the additives did not stick to the pellet surface and were passed through a vibrating sieve with a 50-mesh mesh. 80% of the additive was removed by sieving for minutes.

[Brief explanation of the drawing]

The drawing is a schematic representation of an embodiment of the device according to the invention. 1: Combined resin powder supply pipe, 2: Additive supply pipe, 3: Mixing tank, 4: Rotating obstacle, 5: Projection, 6: Stirring shaft, 7:
Stirring mixer, 8: Layer of mixture of powder and additives, 9:
Upper surface of the mixture layer, 10: Control mechanism for the position of the upper surface of the mixture layer, 11: Discharge port for additive-adhered powder and granular material.

Claims (1)

[Scope of Claims] 1. A method for uniformly mixing and adhering an additive to a synthetic resin powder, comprising: mixing a heated synthetic resin powder and a heat-melting powder additive; The resin powder and the additive are dispersed by colliding with an obstacle in space, and the mixture of the synthetic resin powder and the additive that is dispersed by colliding with the obstacle is stirred and mixed. A method of attaching additives to synthetic resin powder. 2. A synthetic resin powder supply pipe, an additive supply pipe, a mixing tank in which the two supply pipes communicate, and a rotational obstruction provided in the space below the supply port from the supply pipe in the mixing tank. , an agitating mixer provided in the mixing tank below the rotating harmful substance;
and an apparatus for adhering additives to synthetic resin powder, comprising a mechanism for controlling the synthetic resin powder and additive so that the upper surface of a certain mixing agitation layer is maintained below the rotating obstacle.