JPH0957743A - Method for adding additive to synthetic resin particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly mix a liq. or solid additive continuously and without thermal modification and to eliminate special cleaning of the inside of a pipeline when the additive is switched by a method wherein the additive is injected into the pipeline and the additive is continuously dispersed on the surface of synthetic resin particles being pneumatically conveyed in the pipeline. SOLUTION: A method for adding a solid additive to a particulate synthetic resin pref. consists of a method wherein particles flow from the bottom to the top in a vertical pneumatic conveying pipeline 5 and a funnel 13 is provided on the top end of a nozzle 14 for addition provided at angle θ in the flow direction and the solid additive is sucked into the pipeline 5 and is mixed by making the solid additive falling down into the inlet by means of a quantitative feeder. In the case of a liq. additive, it is pref. that the nozzle 14 for addition is inserted into the central part of the pneumatic conveying pipeline 5 and the liq. additive is injected into a nozzle 14 by using a pump. It is possible thereby that the additive is instantaneously dispersed by turbulent and dispersing effect of a flow and is sticked uniformly and continuously on the surface of the resin particles. In addition, the resin particles move by repeating collision on the inner wall of the pipeline and exhibit a self-cleaning effect for the inner wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adding an additive to synthetic resin particles, and more particularly to a method for rapidly and uniformly mixing with a simple device.

[0002]

2. Description of the Related Art Conventionally, additives such as coloring pigments and lubricants and mold release agents have been added to synthetic resins by dispersing solid additives in liquid paraffin or by heating and melting above the melting point of solids. , A method of kneading and mixing with a molten resin by an extruder or a kneader, and then granulating the resin, or charging the resin particles and a solid or liquid additive into a mixer such as a Henschel mixer, a ribbon blender, or a tumbler. The dry blending method is widely used.

[0003]

The former method, however, has the advantage that it can be continuously mixed, but on the other hand, it cannot be used for an additive which is liable to be deteriorated by heat because of a high temperature when kneading with a molten resin. Furthermore, when kneading the pigment, etc., the pigment adheres to the wall surface of the device, and when changing the type or concentration of the pigment, it is necessary to wash the inside of the kneading device with a large amount of purging. However, there was a drawback that many intermediate products were defective.

In the latter method, heat is not applied, so there is no drawback of heat denaturation, but complicated equipment such as a blender and a mixer is required, and in many cases, they are batch-type processes and are not efficient. Further, since the additive adheres to the inner wall of the device, there is a drawback that the inside of the device needs to be cleaned when the kind of the additive is changed. Therefore, the object of the present invention is to solve the contradictory objectives such as continuous treatment without heat denaturation at the same time, with a simple device and without the need for washing with little generation of intermediate products, a method of adding additives to synthetic resin particles. To provide.

[0005]

Means for Solving the Problems As a result of intensive research aimed at achieving the above objects, the present inventors have completed the present invention in which an additive is uniformly added to synthetic resin particles. That is, the present invention is: By adding a liquid or solid additive to the particulate synthetic resin, by injecting the additive into the pipe,
1. An addition method comprising continuously dispersing an additive on the surface of particles of a synthetic resin which is being fed by air in a pipe. 2. The addition method according to the above 1, wherein the additive is liquid liquid paraffin or polyorganosiloxane, or liquid paraffin or polyorganosiloxane containing uniformly dispersed organic and inorganic pigments. Item 1. The additive is one or more kinds of a solid or liquid aliphatic hydrocarbon lubricant, fatty acid lubricant, bisamide lubricant of fatty acid, ester lubricant of fatty acid and alcohol, and metal salt of fatty acid. Is the method of addition.

By injecting the additive into pellets of synthetic resin which are transported at high speed in the pipe together with air,
The additive can be instantaneously dispersed by the turbulent flow diffusion effect of the flow and can be uniformly and continuously adhered to the surface of the resin particles.
Surprisingly, since the resin particles move while repeatedly colliding with the inner wall of the pipe, even if the additive adheres to the inner wall of the pipe, the resin particles themselves have the effect of cleaning, so no special cleaning is required. The generation of intermediate products is low.

The synthetic resin particles referred to in the present invention are thermoplastic and thermosetting resins, and are from 0.05 mm to 1 mm.
Spherical and cylindrical shapes of 0 mm are used, preferably 0.5 mm to 5 mm is useful.

As the liquid additive in the present invention, liquid paraffin, or polyorganosiloxane represented by polydimethylsiloxane or polydiethylsiloxane,
Alternatively, an organic or inorganic pigment dispersed in liquid paraffin or polyorganosiloxane and having a viscosity of 0.1 to 1000 centipoise, preferably 10 to 200 centipoise is useful.

The solid or liquid additives used in the present invention include aliphatic hydrocarbon lubricants represented by polyethylene wax and polypropylene wax, fatty acid lubricants represented by lauric acid and stearic acid, and methylenebisstearic acid amide. , Bisamide lubricants of fatty acids typified by ethylene bis stearic acid amide, carnauba wax, ester lubricants of fatty acids and alcohols typified by montan wax, fatty acids typified by zinc stearate, calcium stearate, magnesium stearate One or a mixture of two or more kinds of the metal salts of, and in the case of a solid, the average particle diameter thereof is preferably in the range of 1 to 1000 μm. When the above additives are heated above their melting points and handled as liquids, the viscosity is preferably 10 to 200 centipoise.

The term "pneumatic pipe" used in the present invention means that the particulate synthetic resin is transported together with air, and the weight ratio of the synthetic resin particles to the air is in the range of 2: 1 to 20: 1. Is preferably in the range of 20 to 40 meters per second, and the Reynolds number is 1 × 10 ³ to 1 × due to the turbulent diffusion effect.
10 ⁷ is preferable.

A method for adding a liquid additive will be described with reference to FIGS. 1 and 3. The addition nozzles are preferably provided in vertical pipes at an angle of θ along the direction in which the particles flow upward from below. θ is preferably 30 to 50 °. It is preferable that 5 is an air feeding pipe, 6 is an addition nozzle, and the tip is inserted to the center of the air feeding pipe. 15 is a nozzle, 16
Is a nut for fixing the addition nozzle and the nozzle with a screw, but the fixing method is not limited to this. A general gear pump, a centrifugal pump or the like may be used for injecting the liquid additive.

A method of adding a solid additive will be described with reference to FIGS. Nozzles 14 are provided at an angle of θ along the direction in which particles flow upward from below, preferably in vertical piping. θ is preferably 30 to 50 °. The diameter of this nozzle is one-fifth or less of the diameter of the pneumatic piping and the length is 50 to 200 mm, and a conical funnel 13 is provided at the upper end thereof. The solid additive is dropped from the funnel-shaped inlet through the metering feeder 12 to be sucked into the pipe and mixed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

[0014]

【Example】

Example 1 A cylindrical polystyrene pellet having a diameter of 3 mm and a length of 6 mm was suction-transported through a pipe having an inner diameter of 65 mm and a length of 30 m. 12 pellets per hour
50 kilograms, air flow rate was 6 cubic meters per minute, and pellet to air weight ratio was 3.5: 1. At the vertical rising part of this pipe, the inner diameter is 4 at an angle of θ = 45 degrees.
A millimeter addition nozzle 6 was provided. A mixed solution of a blue organic pigment and liquid paraffin was injected from the above nozzle by a gear pump in an amount of 0.01 part per 100 parts of the pellet. The product pellets obtained could be continuously manufactured without heat denaturation due to the blue pigment uniformly adhering to the surface.

Example 2 The procedure of Example 1 was repeated except that the addition of the blue pigment was stopped. When a sample of product pellets was taken and inspected every 1 minute after the stop, the influence of the blue pigment disappeared after 5 minutes, and the occurrence of intermediate product defects during switching was small.

Example 3 θ = 45 at the vertical rising portion of the same pneumatic piping as in Example 1.
A nozzle 14 having an inner diameter of 10 millimeters was provided, and a conical funnel 13 was provided at the upper end of the nozzle 14. 0.1 part of a powder of stearic acid having an average particle size of 50 microns was supplied to the above funnel with 100 parts of polystyrene by a quantitative feeder. Pellets in which the additives were uniformly dispersed were obtained.

Comparative Example 1 100 kg of polystyrene pellets were charged in a Henschel mixer having a capacity of 500 liters, 0.01 part of the same blue pigment as in Example 1 was added to 100 parts of the pellets, and a mixing operation was carried out for 10 minutes. The obtained product pellets had the blue pigment uniformly attached to the surface thereof, but the blue pigment was also attached to the inner wall of the mixer and required cleaning.

Comparative Example 2 Molten polystyrene at 250 ° C. was charged into a kneader having a capacity of 50 liters at a rate of 1250 kg / hour. 12 stearic acids
It was melted by heating at 0 ° C., added with a metering pump, and mixed with molten polystyrene by the kneader. The amount added is the same as in Example 3. The obtained polymer was uniformly mixed and there was no cloudiness of stearic acid, but it was colored brown due to stearic acid deteriorated by heat.

[0019]

EFFECTS OF THE INVENTION According to the present invention, liquid and solid additives can be uniformly mixed into the particles of synthetic resin without heat denaturation without requiring a complicated mixing device, Since it has a cleaning effect, special cleaning inside the pipe is not necessary even when the additives are switched, and the generation of intermediate products is small.
Therefore, by using the method of the present invention, it becomes possible to easily and uniformly add the liquid or solid additive to the synthetic resin particles.

[Brief description of drawings]

FIG. 1 is a process diagram showing a method of adding a liquid additive.

FIG. 2 is a process chart showing a method for adding a solid additive.

FIG. 3 is a detailed cross-sectional view of a portion where a liquid additive is added.

FIG. 4 is a detailed cross-sectional view of a solid additive addition portion.

[Explanation of symbols]

 1 Liquid additive tank 2 Pump 3 Pellet 4 Pellet receiving tank 5 Pneumatic pipe 6 Addition nozzle 7 Cyclone 8 Rotary valve 9 Bag filter 10 Suction blower 11 Product pellet 12 Powder metering feeder 13 Funnel 14 Nozzle 15 Nozzle 16 Nut

Claims (3)

[Claims] 1. When adding a liquid or solid additive to a particulate synthetic resin, the additive is injected into a pipe to continuously add the additive to the particle surface of the synthetic resin being air-fed in the pipe. The method of addition is characterized in that the dispersion is carried out. 2. The addition method according to claim 1, wherein the additive is liquid liquid paraffin or polyorganosiloxane, or liquid paraffin or polyorganosiloxane containing uniformly dispersed organic and inorganic pigments. 3. One or more of aliphatic hydrocarbon lubricants, fatty acid lubricants, bisamide lubricants of fatty acids, ester lubricants of fatty acids and alcohols, and metal salts of fatty acids whose additives are solid or liquid. The addition method according to claim 1.