JP2021104654A - Die - Google Patents

Abstract

To provide a die having a function of aligning a fiber orientation in an extrusion direction while preventing fibers from clogging.SOLUTION: Provided is a die 1 for a molding device for extruding and molding fiber materials. The die 1 has a fan-shaped expanding flow channel 10 inside. The cross-sectional area of the channel 10 perpendicular to a material extrusion direction X is constant from an upstream section 11 to a downstream section 13, and the height of both side parts of the channel 10 in a width direction W is lower than the height of a central section formed between both side parts.SELECTED DRAWING: Figure 1

Description

The present invention relates to dies.

Conventionally, in order to obtain a fiber-reinforced molded product in which short fibers and the like are oriented in one direction, a molding apparatus (die structure) in which a through hole (slit) for penetrating a fiber material is provided in the die has been disclosed (a die structure). For example, see Patent Document 1).

Japanese Unexamined Patent Publication No. 63-134219

However, when long fibers or the like are applied, the fibers are entangled with each other in the long fibers, resulting in a cotton-like state. Therefore, when passing through a completely partitioned cross section such as a through hole (slit), the through hole is formed. Threads may be caught between the (slits), and the resin base materials continuing from the rear may be continuously overlapped to form a ball shape, which may block the path and cause clogging.

On the other hand, if a rectifying mechanism such as a slit portion is not provided, when a thermoplastic resin containing reinforcing fibers is extruded by an extruder such as a twin-screw kneader, the base material becomes linear and is contained in the material. The fiber orientation is random. In this case, since the fibers are oriented in the three-dimensional direction, when trying to form a part on a flat surface with a press, the fiber orientations are not aligned in the direction to be reinforced, and the strength cannot be exhibited.

Therefore, an object of the present invention is to provide a die for a molding apparatus which has a function of aligning fiber orientations in an extrusion direction and prevents fibers from being clogged.

One aspect of the present invention is a die for a molding apparatus that extrudes a fiber material.
The die has a fan-shaped expanding flow path inside.
The cross-sectional area perpendicular to the material extrusion direction of the flow path is constant from the upstream part to the downstream part.
A die having a structure in which the height of both side portions in the width direction of the flow path is lower than the height of the central portion formed between the both side portions.

In the die of the above aspect, by making the area of the cross section constant, the fiber material is not biased in the die and is stably discharged. Further, by increasing the height of the flow path on the side of the die and lowering it toward the center, the fiber orientation at each portion of the cross section of the flow path can be made uniform. Moreover, according to the die of this embodiment, since the through hole (slit) or the like is not provided, there is no possibility that the fiber is clogged.

According to the present invention, it is possible to provide a die for a molding apparatus which has a function of aligning fiber orientations in an extrusion direction and prevents fibers from being clogged.

It is a plan view of the die in one embodiment of the present invention, (A) a vertical sectional view on the line AA, (B) a vertical sectional view on the line BB, and (C) a vertical sectional view on the line CC. It is the cross-sectional view of the die shown in the figure (A) on the line (A) 2a-2a, (B) the cross-sectional view on the line 2b-2b, and (C) the cross-sectional view on the line 2c-2c. (A) An image showing Example 1 (experimental data on fiber orientation distribution in a uniform cross-section die), and (B) a diagram showing an analysis shape in the experimental data. Schematic diagram of (A) dice in Example 1 (experimental data on fiber orientation distribution in uniform cross-section dice) and dice in lines A-1 to A-6 in FIGS. (B) to (G). It is an image of the cross section of. (A) An image showing an example of the fiber orientation distribution in the central portion of the die cross section in Example 2 (experimental data on the fiber orientation distribution in the uniform cross-section die under the condition that the height of the upper and lower wall surfaces is lowered), and (B). ~ (G) It is an image of the cross section of the die in each of the lines A-1 to A-6 in FIG. It is a schematic diagram which shows the T die which is an example of the existing die which has the structure similar to the die of this embodiment.

Hereinafter, embodiments of dies for molding equipment will be described with reference to FIGS. (see FIGS. 1 to 5 and the like). In addition, in FIGS. 1 and 2, the thickness of the originally thick die wall surface is simply indicated by a line.

The die 1 is a die for an extrusion molding apparatus used in an extrusion process of a thermoplastic resin or a thermosetting resin containing reinforcing fibers, and has a flow path 10 of a fiber material at the time of extrusion molding inside. (See Fig. 1 etc.).

The die 1 has an overall structure in which the flow path 10 is expanded in a fan shape from around the extrusion port 1a of the upstream portion 11. The flow path 10 is formed so as to expand in a fan shape from the upstream portion 11 to the downstream portion 13.
The cross section of the cross section (cross section) perpendicular to the material extrusion direction X of the flow path 10 changes in shape along the extrusion direction X, but in order to keep the resin volume extruded per unit time constant, the normal direction. It is formed so that the cross-sectional area (cross-sectional area of the cross section) is constant.

There are three types of flow path widths of the flow path 10 of the die 1 in the present embodiment, and the die 1 has three patterns of flow paths 10. Each pattern uses the height of the die 1 as a variable. In the upstream portion 11, the flow path height is set to be the highest ( _{see the symbol t in} in FIG. 1 (A)), and in the downstream portion 13, the flow path height is set to be the lowest (see the _{symbol t out in FIG. 1 (A)).} ). The intermediate portion 12 has a structure in which the upstream portion 11 and the downstream portion 13 are connected by a gradually changing fillet. The gradual change section of the flow path 10 continues to the extrusion outlet 1b of the die 1.

_{Further, in the die 1 of the present embodiment, the height t E} on the side wall of both side portions 10E in the width direction W of the flow path 10 is higher than _{the height t C of the} central portion 10C formed between the both side portions 10E. Is also low (see Fig. 2).

As is clear from the above description, according to the die 1 of the present embodiment,
-By making the cross-sectional area of the flow path 10 constant, the material is not biased in the die 1 and can be discharged stably.
-For one of the purposes of aligning the fiber orientation of the extruded resin base material, the height of the flow path at the end 10E of the flow path 10 of the die 1 was raised and lowered toward the center to achieve a cross section. The fiber orientation at each part of the above can be made more uniform.
-By continuing the gradual change section up to the extrusion outlet 1b, the increase in the flow internal pressure of the resin is suppressed, and damage to the extrusion equipment is prevented.
-Since it does not have through holes (slits), there is no risk of fiber clogging.

Although the T die exists as an existing die having a structure similar to that of the die 1 as in the present embodiment, the T die has a gradual change section of the flow path (see reference numeral B in FIG. 6, and reference numeral A is an extrusion inlet. , C is a section where the cross section of the flow path is uniform, and D is an extrusion outlet), which does not continue to the die outlet, and the entire plate thickness becomes uniform from the middle of the flow path. It is very different (see FIG. 6).

It should be noted that the embodiments described above are for facilitating the understanding of the present invention, and are not for limiting and interpreting the present invention. Each element included in the embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those exemplified, and can be changed as appropriate. In addition, the configurations shown in different embodiments can be partially replaced or combined.

For example, the "height" in the above-described embodiment means the height in the vertical direction when the wide direction (width direction W) of the die 1 is horizontal, and the die is tentatively rotated by 90 ° and placed vertically. It is a concept that can be applied by appropriately changing the direction and allies from such a viewpoint even for (a state in which the "height" in the vertical direction is in the horizontal direction).

An experiment was conducted on the fiber orientation distribution in a uniform cross-section die, and data were obtained (see FIG. 3).

It can be seen that in the cross section perpendicular to the extrusion direction X, the fiber orientation at both ends of the die (near the side wall surface) is in the flow direction (extrusion direction X), and in the center of the cross section, it is in the normal direction with respect to the flow direction. (See Fig. 4).

From this, it was found that the fiber orientation can be directed in the flow direction (extrusion direction X) even when _{the height t E} of both ends 10 E of the die 1 is high. On the other hand, since the central portion 10C faces the normal direction with respect to the flow, it is necessary to bring the upper and lower wall surfaces of the die closer (in other words _{, lower the height t C} ) and control the orientation by shear strain from the upper and lower wall surfaces. I understood.

An experiment was conducted on the fiber orientation distribution in a uniform cross-section die under the condition that the height of the upper and lower wall surfaces of the die 1 was lowered, and data were obtained (see FIG. 5). It was confirmed that the fiber orientation was oriented in the flow direction (extrusion direction X) even in the central portion 10C in the die 1 by bringing the upper and lower wall surfaces closer to each other (suppressing the height). However, since the flow pressure in the shape of the left exceeds the equipment allowable value becomes higher 20 MPa, (to increase the height t _E of the both end portions 10E) thick at both ends, contrivance such as direct before the fiber orientation while lowering the internal pressure It turns out that it is important to do.

The present invention is suitable for application to dies for molding equipment.

1 ... Dice, 1a ... Extrusion inlet, 1b ... Extrusion outlet, 10 ... Flow path, 10C ... Central part, 10E ... End part, 11 ... Upstream part, 12 ... Middle part, 13 ... Downstream part, W ... Width direction, X … Extrusion direction, t _C … height at the center, t _E … height at both sides,

Claims (1)

A die for a molding machine that extrudes a fiber material.
The die has a fan-shaped expanding flow path inside.
The cross-sectional area perpendicular to the material extrusion direction of the flow path is constant from the upstream portion to the downstream portion.
A die having a structure in which the height of both side portions in the width direction of the flow path is lower than the height of the central portion formed between the both side portions.

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