JPH02310008A - Continuous extruding and granulating device - Google Patents

Abstract

PURPOSE:To enable an improvement in productivity in granulation of a dustless thermosetting resin molding material and the granulation of phenolic resin molding material whose viscosity is high and thermal stability is short, by a method wherein a gap between the top of a screw and die-possessing straight die holes which are flush with each other is made into 1mm or narrower. CONSTITUTION:A material kneaded by a double-screw kneading machine is entered into a single-screw extruding and granulating machine and transferred forward. The transferring material is followed by heating due to shearing force and frictional force of the same with a screw, cylinder and die and melting and reaction are advanced. The material which is transferred away up to the tip part of the screw is pressed against a die hole 6 and after passing through the die hole 6, hot cutting of the same is performed by a hot-cutting blade 7. In this instance, since a die 5 pulsates with extruding force and a gap 9 between the top 3 of a screw shaft and the die 5 does not widen away. When the gap 9 between the die and screw is controlled so as not to exceed 1mm, the material intruding away into the gap is discharged swiftly in a circumferen tial direction with a rotation of the screw. Therefore, a pulsation is not generat ed on the die.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a continuous extrusion granulation device for continuously granulating a plastic molding material.

[Conventional technology]

As a conventional device for performing extrusion granulation, there is a device having a mechanism for hot-cutting a single-screw extrusion molded material.

However, in all of these devices, a certain gap is provided between the screw tip and the die, that is, a reservoir is provided so that the molten material passes through the flow path of the die with uniform pressure. Such a reservoir is good for materials with low melt viscosity and good thermal stability, but for thermosetting resin molding materials with high melt viscosity, especially phenolic resin molding materials, this reservoir and die hole can prevent curing clogging. It was difficult to raise and granulate by continuous extrusion.

Another conventional device is one in which the distance between the screw tip and the die is short, but the die uses a thin screen die to extrude the material, and the extruded material is crushed in a crusher to form granules. . Since the screen die of this device is thin, pulsation during operation creates a gap between the screw tip and the screen die, and in the case of a thermosetting resin molding material with a short thermal stabilization time, it hardens, further solidifies, and becomes continuous. Extrusion becomes impossible. Another disadvantage is that it cannot be hot cut due to the pulsation of the die.

The molding material with a high melt viscosity referred to here means an apparent viscosity of 100,000 at 120°C measured by a Koka type flow tester.
Refers to something more than poise, and has short thermal stability +A
This means that if the molding material is left in the cylinder of an injection molding machine, it will break down within 30 minutes! Refers to molding materials that cause oxidation. Most of the phenolic resin molding materials have a thermal stability retention time of about 5 to 10 minutes and an apparent viscosity of 100,000 poise or more at 120°C.
This applies to the molding materials listed above.

[Problem to be solved by the invention]

The purpose of the present invention is to provide an apparatus for producing a so-called dust-free molding material that continuously granulates a thermosetting resin, particularly a phenolic resin molding material, and does not generate dust during molding or tablet making. It's about doing.

[Failure to solve the problem]

As an example is shown in FIG. 1, the present invention provides a single-screw extrusion granulation device in which the screw shaft tip surface (3) and the flight tip surface (3') of the screw are on the same plane and are straight. This extrusion granulation device is characterized in that it has a die hole (6) of 1 mm, and a gap (9) between the tip end face and the die (5) of 1 mm or less.

The single-screw extrusion granulator used in the present invention is based on the extrusion granulator used for thermoplastic bamboo resin molded rice, but the shape of the screw and die has been improved. That is, the tips of the screws are made flush, and the dies are straight-hole dies with sufficient strength. The screw shaft end surface (3) is preferably processed to be flat so that the cross-wire material (1) can be easily pressed against the die (5). The die (5) must be precisely machined to have sufficient strength to maintain a gap of 1 mm or less with the screw shaft end surface (3) without pulsating during operation. If there is a gap of 1 cylinder or more, the crosstalk material (1
) will adhere and further harden, significantly interfering with continuous operation.

The die (5) must have the strength to withstand extrusion pressure so that the die surface does not pulsate during bot canting, and must also have a certain thickness so that the extruded material does not expand at the exit of the die. . On the other hand, in order to prevent curing from occurring in the die hole, it is necessary to make the aperture ratio of the die hole as large as possible5 and to make the die thickness as thin as possible to reduce the loss of pressure Ii1 in the die hole. As a means to solve these problems, thicker dies are used.
Good operation can be achieved if the distance is set within the range of 20 mm to 20 mm.

As a result of various studies, it was found that it is preferable to keep the die hole diameter the same rather than varying the hole diameter.

Regarding the pitch of the die holes, if the hole pitch is smaller than the hole diameter, the extruded 44F4 will often fuse again at the die exit, so it is necessary to set the hole pitch according to the material to be granulated. It is. Normally, the hole pinch is preferably 1.0 to 3.0 times the hole diameter.

For the position of the die hole, please refer to the tip of the screw shaft (3).
Since the screw has no function of extruding material, it is preferable to provide a die hole (6) along the flight part of the screw.

[For production]

An example of the present invention will be explained with reference to the drawings along with its operation.

The material kneaded in a twin-screw kneader etc. enters the single-screw extrusion granulator (Figure 1 = 4-) and is transferred forward by a screw 6
The material to be transferred must be equipped with an accurate temperature control device for screws, cylinders, machines, and dies. At the tip of the screw, the resistance force required to pass through the die hole becomes extremely high, and the temperature of the transferred material rises rapidly. When the temperature of a phenolic resin molding material exceeds 125'C, a crosslinking reaction tends to occur, so the temperature of the material must be controlled so as not to exceed 125'C.

The material transferred to the tip of the screw is forced into the die hole (6), and after passing through the die hole (6), it is canted by a hot cut knife (7). At this time, the die (5) must not pulsate due to extrusion pressure and the gap (9) between the screw shaft tip surface (3) and the die (5) should not widen.

If the gap (9) between the die and the screw is controlled to be 1 mm or less, the material that has entered this gap is quickly discharged in the circumferential direction by the rotation of the screw. Therefore, no pulsation of the dice occurs.

〔Example〕

Two-screw blend B of the formulation in Table j! A 60cm0 material O'1 was prepared using a machine 7Ea Gen L7 and a Suba 1' Ralph flow, and was immediately extruded using the continuous extrusion device of the present invention shown in Figure 1 under the extrusion granulation conditions shown in Table 2. Granulated.

Table 1 Formulation Table 2 Extrusion granulation conditions As a result, dust-free Spiral [J-50C1n
, a good molding material of 1"l with an L throat shape of 28φ x 2.5 mm was obtained. The temperature of the molding material in the die was IIO'C. The generality of the molding material obtained was as shown in Table 1. 3.

Table 3 - Seatability [Effects of the Invention] As is clear from the explanation below-1-, according to the present invention, dust-free thermosetting + 1F resin molding (A 1: l molding, γ Not only can it be manufactured with good productivity, it also enables the granulation of phenolic resin molding materials that have high viscosity and short thermal stability, which could not be conventionally oxidized.Therefore, it is possible to produce industrial thermosetting resin molding materials. It is extremely suitable as a device.

[Brief explanation of drawings]

FIG. 1 is a side view of the central shaft extrusion granulation apparatus of the present invention (inner side of the cylinder). Patent applicant Sumitomo Bakelite Co., Ltd. Figure 1□--: ==== ==== ! ==== □□□: Chair/screw gap 5 Die 3' Screw flight tip surface 3 Screw single shaft tip surface 6 Die hole 7 Hot cut blade snow

Claims (1)

[Claims] (1) In a single-screw extrusion granulator, the tip surface of the screw shaft and the tip surface of the flight are on the same plane, the die has a straight die hole, and the gap between the tip surface and the die is 1 mm or less. An extrusion granulation device characterized by: