JPH07198712A - Method and device for measuring compression characteristic of molten resin - Google Patents

Abstract

PURPOSE:To improve the leakage preventing function of a device for measuring compression characteristics of molten resins against a molten resin by improving the using mode of a sealant made of rubber, etc., used at the time of measuring the compression characteristic of the molten resin together with a piston, etc. CONSTITUTION:After respectively putting a nut 5, rubber sealant 4, and thread part 3 on the lower part 2 of a piston, the thread part 3 is tightened against the lower part 2 and the nut 5 is tightened against the sealant 4. As a result, the sealing property of the sealant 4 against a molten resin is improved, because the sealant 4 swells and becomes thicker than the outer diameter of the piston as the sealant 4 is pressed by the tightening force of the nut 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten resin compression characteristic measuring method and a molten resin compression characteristic measuring device.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional molten resin compression characteristic measuring method and a piston structure used in the apparatus. A threaded portion 3 is screwed into the piston body 1 and the piston lower portion 2, and a rubber material 4 for sealing is sandwiched between the piston body 1 and the piston lower portion 2. The rubber material 4 is formed to be slightly thicker than the outer diameter of the piston body 1, so that when it is inserted into a cylinder (not shown) and the molten resin is compressed, the rubber material 4 is formed between the cylinder inner wall and the outer peripheral surface of the piston body 1. The structure prevents the molten resin from leaking from the clearance.

[0003]

However, in order to further pressurize the resin, which becomes low in viscosity when pressed at high temperature,
In the method using the piston, the specific volume of the molten resin changes considerably, and the rigidity of the sealing material made of rubber decreases significantly at high temperatures. There is a problem that the resin leaks even from the inside (see FIG. 1).

In view of such conventional problems, the present invention has been made.
An object of the present invention is to provide a molten resin compression characteristic measuring method and a molten resin compression characteristic measuring device in which a sealing material such as rubber used with a piston is improved in use to improve a leakage preventing function of molten resin.

[0005]

In order to achieve the above object, a method for measuring a compression characteristic of a molten resin according to the present invention has the following characteristics: A sealing material that is compressed by the pressure of the molten resin and prevents the molten resin from leaking is interposed between the tip of the piston and the molten resin.

The molten resin compression characteristic measuring method according to the present invention may have a structure in which the surface of the sealing material which is in contact with the molten resin has a gradient.

In order to achieve the above object, the molten resin compression characteristic measuring device according to the present invention is a piston compression method for a molten resin compression characteristic measuring device in a molten resin compression characteristic evaluation device. A sealing material for preventing leakage of molten resin is sandwiched between a nut and a screw and tightened at the tip of the above to be deformed to be thicker than the outer diameter of the piston and attached.

The molten resin compression characteristic measuring device according to the present invention may be configured such that the sealing material is sandwiched between the screw and the spacer to be tightened and deformed.

The molten resin compression characteristic measuring device according to the present invention may be configured to use a sealing rubber material as the sealing material.

The molten resin compression characteristic measuring device according to the present invention may be configured to use Teflon as the sealing material.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the molten resin compression characteristic measuring method and apparatus according to the present invention will be described below with reference to the drawings. Note that, in the following, the same parts as those of the related art will be described with the same reference numerals.

The piston structure of this embodiment is shown in FIGS. As shown in the drawing, a nut 5, a rubber member 4 for sealing, and a screw portion 3 are attached to the piston lower portion 2 in this order. The screw portion 3 is appropriately screwed into the piston lower portion 2 and then the nut 5 is attached to the rubber member. Pressurize by tightening against 4,
As shown in FIG. 1, the piston body 1 is expanded and deformed so as to be thicker than the outer diameter thereof. This improves the sealing property against leakage of the molten resin. In order to adjust the amount of deformation of the seal material, the amount of tightening the nut 5 may be changed.

FIG. 3 shows an embodiment in which a spacer 6 is used instead of the nut 5 of the previous embodiment. In this example, a spacer 6, a rubber member 4 for sealing, and a screw portion 3 are provided on the lower portion 2 of the piston.
Then, the threaded portion 3 is screwed into the piston lower portion 2 and tightened to pressurize, and the rubber material 4 is expanded and melted so as to be considerably thicker than the outer diameter of the piston body 1 as in the previous example. Improves sealing performance against resin leakage. In order to adjust the amount of deformation of the sealing material, the length of the spacer 6 may be changed.

By using Teflon instead of a rubber material for the sealing member, the rigidity in the high temperature region may be increased and the sealing effect may be further improved. The material of the sealing member may be appropriately selected depending on the measurement temperature range.

FIG. 4 shows an embodiment of the method for measuring the compression characteristic of molten resin according to the present invention. In this embodiment, as shown in the drawing, the sealing material 11 attached to the lower end of the piston 10 is attached to the molten resin 1
It is a measuring method that is arranged so as to be sandwiched between the two. The sealing material 11 is deformed by receiving a high pressure as the molten resin 12 is heated and expands, and eliminates the clearance between the outer peripheral surface of the piston 10 and the cylinder wall surface (not shown) to improve the sealing performance, thereby performing a good measurement. It is possible. A slope 13 is provided on the end surface of the sealing material 11 so that the pressure of the molten resin 12 is easily received.

[0016]

As described above, the molten resin compression characteristic measuring method and apparatus according to the present invention loses the pressure of the molten resin by pressurizing and deforming the sealing material for preventing leakage attached to the piston. It is possible to secure a non-sealing property, facilitate measurement of resin compression characteristics in a high temperature region, and improve repeatability. There is also an effect that the amount of deformation of the sealing material can be easily adjusted.

[Brief description of drawings]

FIG. 1 is an enlarged partial sectional view showing a piston structure used in an embodiment of a molten resin compression characteristic measuring device according to the present invention.

2 is a partial cross-sectional view of the piston structure of FIG.

FIG. 3 is a partial cross-sectional view showing another piston structure used in one embodiment of the molten resin compression characteristic measuring device according to the present invention.

FIG. 4 is a partial cross-sectional view showing an embodiment of the method for measuring the molten resin compression characteristic according to the present invention.

FIG. 5 is a partial cross-sectional view showing an example of a piston structure used in a conventional molten resin compression characteristic measuring device.

FIG. 6 is a compression characteristic diagram showing the relationship between the temperature of molten resin and the specific volume.

[Explanation of symbols]

 1 Piston main body 2 Piston lower part 3 Screw part 4 Rubber material 5 Nut 6 Spacer 10 Piston 11 Sealing material 12 Molten resin 13 Gradient

Claims (6)

[Claims] 1. A method for measuring a molten resin compression characteristic in a molten resin compression characteristic evaluation device using a piston method, comprising:
A method for measuring a compression characteristic of a molten resin, characterized in that a sealing material, which is compressed by the pressure of the molten resin in the cylinder and prevents leakage of the molten resin, is interposed between the tip of the piston and the molten resin. 2. The method for measuring a compression characteristic of a molten resin according to claim 1, wherein a surface of the sealing material which is in contact with the molten resin is provided with a gradient. 3. A molten resin compression characteristic measuring device in a molten resin compression characteristic evaluation device by a piston method,
Melt resin compression characteristics characterized in that a seal material that prevents leakage of molten resin is clamped by nuts and screws at the tip of the piston that compresses molten resin in the cylinder, and is tightened and deformed thicker than the piston outer diameter measuring device. 4. The molten resin compression characteristic measuring device according to claim 2, wherein the sealing material is clamped and clamped by the screw and a spacer to be deformed. 5. A molten resin compression characteristic measuring device according to claim 3, wherein a rubber material for sealing is used as said sealing material. 6. The molten resin compression characteristic measuring device according to claim 3, wherein Teflon is used as the sealing material.