JPH072189Y2 - Foam extrusion molding equipment - Google Patents

Description

[Detailed description of the device]

[0001]

[Industrial application] This device is made of plastic, rubber,
This is to improve the foam extrusion molding equipment for thermoplastic elastomers.

[0002]

2. Description of the Related Art The internal pressure of an extrusion port side cylinder of a foam extrusion molding machine is mainly determined by the flow resistance of the die and the extrusion amount depending on the shape of the screw. Therefore, if a large die with a small flow resistance is replaced with a smaller die and extrusion molding is performed on the foamed resin, the pressure inside the cylinder on the extrusion port side increases and the resin from the foaming gas or foaming agent injection port opened on the cylinder inner wall May escape or solidify and block the inlet. Therefore, when replacing the die with a small size, the screw is also replaced with a small extrusion amount.

[0003]

[Problems to be Solved by the Invention] It is relatively easy to change the die, but the work of changing the screw becomes a big task.
This device sought a way to avoid changing screws.

[0004]

The foam extrusion molding apparatus of the present invention is a plastic material extrusion molding apparatus having a screw cylinder with an injection port for a foaming gas or a foaming agent. On the inner circumference of the cylinder, there is a diameter-increasing region where the cylinder inner diameter gradually increases and decreases locally, and at the position where the extrusion screw shaft enters the diameter-increasing region, there is a circular collar-shaped throttle part. The extruding screw is adjustable in the axial direction, and by moving the throttle portion to an arbitrary position in the diameter increasing area, the throttle degree and the cylinder internal pressure due to the throttle degree are adjusted to be adjusted from the inlet. The feature is that it can prevent the escape of plastic material.

[0005]

[Function] In the case of a foam extruding device in which dies having different flow path resistances are exchanged for use, it was common knowledge that the screw should have a small extrusion amount when the extrusion port of the die becomes small. Even if the amount is too large, we have embodied the idea that if the cylinder pressure is not made too large, it is possible to prevent backflow to the foam material inlet. That is, by providing a diameter-increasing region on the cylinder inner wall and a circular collar-shaped throttle portion on the screw shaft to form a cylinder with a variable throttle device, and adjusting the throttle, the internal pressure in the latter half of the cylinder including the vicinity of the inlet can be adjusted. did. Even if the extrusion port of the die becomes smaller, the screw cannot be replaced, and when the resin may escape from the injection port, this can be prevented by merely adjusting and moving the screw shaft.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a longitudinal sectional view of the essential part of one embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 is a screw, 2 is a cylinder, 3 is a raw material charging port, 4 is a foaming gas or a foaming agent inlet, 5 is a variable-diameter increasing area on the inner wall of the cylinder, and 6 is a circular collar-shaped throttle portion provided on the screw shaft. Is. The increased diameter region 5 and the screw shaft throttle portion 6 are shown in an enlarged manner in FIG. Since the axial adjustment movement mechanism of the screw 1 is well known, its illustration and description are omitted.

Since the throttle portion in FIG. 2 is located near the entrance of the diameter increasing area 5, the degree of throttling is large, and the degree of throttling decreases as it moves further to the right and approaches the center of the diameter increasing area 5. Needless to say, the larger the degree of throttling, the higher the internal pressure of the cylinder including the vicinity of the inlet 4, and the smaller the degree of throttling, the easier the resin will escape to the rear of the cylinder. The injection pressure from can not be exceeded.

[0008]

EFFECTS OF THE INVENTION This device simplifies on-site work all at once by confronting the blind spots of the prior art. The foam extruder has a problem of backflow to the foam material injection port, which is not found in general extruders. It suffices that the size of the die extrusion port and the extrusion amount of the screw are in balance, but when the die size is changed and the extrusion amount becomes excessive, the above-mentioned backflow occurs. In order to prevent this, the conventional fixed concept that the screw must be replaced, this invention, even if the screw extrusion amount is too large,
It was demonstrated that backflow can be prevented by adjusting the internal pressure with a variable throttle device.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an essential part of an embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view of a diameter-increasing region and a throttle portion.

[Explanation of symbols]

 1 Screw 2 Cylinder 4 Injection Port 5 Increase Area 6 Restriction

Claims (1)

[Scope of utility model registration request] 1. A plastic material extrusion molding apparatus having a screw cylinder having an injection port for foaming gas or a foaming agent, and a die having different flow path resistance is exchanged for use. The plastic material extrusion molding device is slightly closer to the raw material injection port than the injection port. The inner diameter of the cylinder has a diameter increasing region where the cylinder inner diameter is gradually increasing and decreasing locally, and the position of the extrusion screw shaft entering the diameter increasing region is
There is a circular collar-shaped squeezing part, and its extrusion screw can be adjusted and moved in the axial direction.By moving the squeezing part to an arbitrary position in the diameter increasing area, the squeezing degree and the silling internal pressure due to this can be adjusted. The foam extrusion molding apparatus is characterized in that the plastic material can be prevented from escaping from the injection port.