JPH0565523U - Foam extrusion molding equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the backflow of raw material resin from the injection port for foaming gas or foaming agent. [Structure] A diameter-increasing region 5 where the cylinder inner diameter is locally gradually increased or decreased is provided in the inner circumference of the cylinder 2 slightly closer to the raw material charging port 3 than the position of the inlet 4, and the screw 1 is provided with a throttle portion 6. Allows variable aperture. The screw 1 is adjusted and moved in the axial direction to lower the cylinder internal pressure in the vicinity of the inlet 4 and prevent resin backflow.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to the improvement of the foam extrusion molding device.

[0002]

[Prior Art]

 The extrusion port side cylinder pressure of the foam extrusion molding machine is mainly determined by the flow path resistance of the die and the extrusion amount depending on the screw shape. Therefore, if a large die with low flow resistance is replaced with a smaller die and foamed resin is extrusion-molded, the cylinder internal pressure on the extrusion port side increases, and the foaming gas or foaming agent injection port opened on the cylinder inner wall is used. The resin escapes or solidifies, blocking the inlet. Therefore, when replacing the die with a small size, the screw is also replaced with one with a small extrusion rate.

[0003]

[Problems to be solved by the device]

 Changing dies is relatively easy, but changing screws is a big task. This device sought a way to avoid changing screws.

[0004]

[Means for Solving the Problems]

 The foam extrusion molding apparatus of the present invention is a plastic material extrusion molding apparatus in which a screw cylinder has an injection port for a foaming gas or a foaming agent, and the cylinder inner diameter is closer to the raw material injection port than the position of the injection port. Has a region of increasing diameter that gradually increases and decreases locally, and there is a circular collar-shaped throttle at the position of the extrusion screw shaft that enters the region of increasing diameter. Adjustable movement is possible, and by moving the throttle part to an arbitrary position in the diameter increasing area, it is possible to prevent the plastic material from escaping from the injection port by adjusting the degree of contraction and the cylinder internal pressure due to this. It is characterized by having done.

[0005]

[Action]

 In this invention, a diameter-increasing region is provided closer to the raw material inlet than the positions of the foaming gas and the foaming agent inlet provided in the cylinder, and the screw shaft that enters the diameter-increasing region is provided with a circular collar-shaped throttle portion. Since the screw shaft can be adjusted and moved in the axial direction, it becomes a screw cylinder with a variable throttle device. By adjusting the throttle, the internal pressure of the latter half of the cylinder including the vicinity of the injection port can be adjusted. When the internal pressure of the latter half of the cylinder is adjusted, that is, when the flow path resistance of the die becomes stronger and resin may escape from the injection port, this can be prevented by simply adjusting and moving the screw shaft.

[0006]

【Example】

 FIG. 1 is a longitudinal sectional view of an essential part of one embodiment of the present invention, in which 1 is a screw, 2 is a cylinder, 3 is a raw material inlet, 4 is a foaming gas or a foaming agent inlet, and 5 is a variable throttle on the inner wall of the cylinder. A diameter-increasing region for use, 6 is a circular collar-shaped throttle portion provided on the screw shaft. The enlarged 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 becomes smaller 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 area near the inlet 4, and if the degree of throttling is reduced, the resin will easily escape to the rear of the cylinder, and the pressure inside the cylinder near the inlet 4 will decrease. The injection pressure from can not be exceeded.

[0008]

[Effect of the device]

 The idea is that the variable throttling mechanism that adjusts the degree of throttling of the screw throttling portion by adjusting the axial movement of the screw is extremely effective in preventing the escape of resin from the foaming gas and foaming agent injection port of the foam extrusion molding device. Was presented for the first time. As a result, when replacing the extrusion die with a smaller size, the conventional on-site work, which had to be replaced with a screw with a small extrusion rate, was greatly reduced.

[Submission date] March 18, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

[Industrial applications]

 This invention relates to improvement of foam extrusion molding equipment for plastics, rubbers, thermoplastic elastomers and the like.

[Brief description of drawings]

FIG. 1 is a longitudinal 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 narrowed portion.

[Explanation of symbols]

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

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[Procedure amendment]

[Submission date] March 18, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Item name to be amended] Scope of utility model registration request

[Correction method] Change

[Correction content]

[Scope of utility model registration request]

Claims (1)

[Scope of utility model registration request] 1. A plastic material extrusion molding apparatus having an injection port for a foaming gas or a foaming agent in a screw cylinder, wherein the cylinder inner diameter is locally located at the cylinder inner circumference near the raw material injection port from the position of the injection port. It has a diameter increasing area that gradually increases and decreases, and there is a circular collar-shaped throttle at the position where the extrusion screw shaft enters the diameter increasing area, and the extrusion screw can be adjusted and moved in the axial direction. By moving the throttle part to an arbitrary position in the increased diameter area,
A foam extrusion molding apparatus, characterized in that the degree of drawing and the cylinder pressure due to this can be adjusted to prevent the escape of plastic material from the injection port.