JPS6236853B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a die for manufacturing a foam sheet having ridges on its surface.

Foam sheets having ridges on the surface are already known. Foamed sheets with ridges on the surface not only have good cushioning properties, but also have good cushioning properties because the foamed ridges come into contact with other objects with gaps. Moreover, it has the advantage of being easy to peel off from other objects. However, in conventional sheets, the protrusions were not formed noticeably, and the protrusions were more easily deformed than the sheet body, so even though they were formed into protrusions, the effect was It was scarce.

The inventor attempted to produce a foam sheet with ridges that does not have the above-mentioned drawbacks. For this purpose, improvements were made to the equipment for manufacturing foam sheets. The improvement was made to a die for manufacturing foam sheets by extrusion. Specifically, in order to form a protrusion on the sheet within the cap, both sides of the protrusion were formed by gradually narrowing planes, and the included angle between the two sides was set to 15 to 90 degrees. . This way,
It was confirmed that the outline of the protrusions became clear and that the protrusions were difficult to deform. This invention was made based on such confirmation.

This invention provides a die for manufacturing foam sheets having an annular or linear slit along the outlet side, in which a large number of protrusions are attached to the outlet end of one wall surface forming the slit, the protrusions projecting toward the opposite wall surface. However, both sides of the protrusion rising from the wall surface are substantially planar, and the protrusion width is inclined so as to gradually increase along the direction of resin propagation, and the included angle between both sides is 15 to 90 degrees. The present invention relates to a die for manufacturing a foam sheet having a characteristic feature of ridges on the surface.

The present invention will be explained based on the drawings as follows. FIG. 1 is a longitudinal sectional view of a cap according to the present invention. Figure 2 shows the dotted line a in Figure 1.
FIG. 3 and 4 are partially cutaway enlarged views of the outlet end face of the cap according to the present invention. 5 and 6 are partially cutaway vertical sectional views of the vicinity of the outlet end of the mouthpiece according to the present invention.

FIGS. 1 and 2 take as an example a die in which an annular slit is formed between an outer mold and an inner mold. In these figures, 1 is an outer mold, 2 is an inner mold, 3 is a cylindrical gap, 4 is a wall surface of the outer mold, 5 is a wall surface of the inner mold, and 6 is a protrusion.

The caps shown in FIGS. 1 and 2 have a structure as described below. The inner mold 2 is inserted into the outer mold 1 and fixed within the outer mold 1 by bridge portions 21 radially projecting from the inner mold 2. As a result, a cylindrical gap 3 is formed between the outer mold 1 and the inner mold 2. Heat-softened foaming resin is supplied into the cylindrical gap 3 along the direction of the arrow x, and the resin is supplied into the cylindrical gap 3.
It is formed into a cylindrical shape and extruded. The extruded resin is foamed to form a cylindrical molded body. The cylindrical molded body is
It is cut open and made into foam sheets. The process up to this point is the same as for conventional caps.

In the base of the present invention, the 1 which forms the cylindrical gap 3 is
A large number of protrusions 6 are formed at the outlet ends of the two wall surfaces 4. The difference between the cap of this invention and the conventional cap is that
This is the shape of the protrusion 6. That is, the protrusion 6 is attached to the outlet end of one wall surface, for example, the wall surface 4, and projects toward the other wall surface 5. Also,
Both side surfaces 7 and 8 of the protrusion 6 are surfaces that stand up from the wall surface 4, but both side surfaces 7 and 8 are substantially planar and extend along the direction in which the resin travels. The width is inclined to increase gradually. Moreover, the slopes of both side surfaces 7 and 8 are substantially symmetrical with respect to each other along the direction in which the resin travels. The included angle between the sides 7 and 8 is between 15 and 90 degrees.

The above-described structure of the protrusion 6 may be provided at the outlet end of the mouthpiece. In other words, both sides 7 and 8
This means that the protrusion width does not necessarily have to gradually increase near the inner end 61 of the protrusion 6, and it does not have to be symmetrical. However, what is desirable is the inner end 6
1 is pointed, and both side surfaces form two sides of an isosceles triangle with the inner end 61 as the apex.

The shape of the protrusion 6 viewed from the outlet end of the cap is not limited to that shown in FIG. 2. As shown in Figure 3,
The protrusion 6 may have a trapezoidal shape at the end of the mouthpiece, and adjacent protrusions may be in contact with each other at one point on the wall surface 4 of the outer mold 1. Further, as shown in FIG. 4, protrusions 6 may be attached adjacent to each other on the wall surface of the outer mold 1, and protrusions 6 may also be attached adjacent to each other on the wall surface of the inner mold 2. In this case, the protrusion 6 on the outer mold
It is desirable that the protrusion 6 on the inner mold and the protrusion 6 on the inner mold be attached with a phase shift. In either case, both side surfaces 7 and 8 of one protrusion 6 are provided symmetrically with the protrusion width being inclined along the resin traveling direction.

The shape of the tip of the protrusion 6 protruding toward the opposing wall surface is also not limited to that shown in FIG. 2. In FIG. 2, the tip surface 62 of the protrusion 6 is shaped like a plane substantially parallel to the wall surface 5, but as shown in FIG. The tip 9 may form one ridge line and be inclined with respect to the wall surface 5, so that the thickness of the gap 3 gradually decreases. Also, as shown in Figure 6,
A protrusion 6 as shown in FIG. 5 is provided on the wall surface 4 of the outer mold 1, and a protrusion 6 is also provided on the wall surface 5 of the inner mold 2. It may have a slope of

The above description has been made with respect to a cap with an annular slit, but the same applies to a cap with a straight slit. In other words, in the case of a linear slit, the second
In the figure, the outer mold 1 is the upper mold and the inner mold 2 is the lower mold, and the other relationships are exactly the same as in the case of the annular slit.

In the die of this invention, the exit end of one wall surface forming the slit is provided with a large number of protrusions that protrude toward the opposite wall surface, so when extrusion molding is performed using this die, the surface has protrusions. A foamed sheet with a ridge is obtained, and the ridges have a cross section corresponding to the valley of the ridges. Furthermore, in the base of the present invention, both side surfaces of the protrusion rising from the wall surface are substantially planar, and are inclined so that the protrusion width gradually increases along the resin traveling direction, so that the included angle between the two side surfaces is 15 or more.
Since it forms a 90-degree angle, the resin is gradually compressed from both sides to form protrusions. Therefore, both sides of the protrusion are clearly formed. Therefore, the protrusions are strong and exhibit a cushioning action with greater elastic resistance than other parts. As described above, the cap of the present invention provides unique effects in that the protrusions are clearly formed and a foamed sheet with strong cushioning properties is provided on the protrusions.

In addition, regarding FIG. 2, the dimensional relationship of the protrusion 6 will be explained as follows. The relationship between the width W of the exit end of the protrusion 6 and the gap V between adjacent protrusions 6 is W
is 0.5 to 50 mm, preferably 1 mm to 10 mm, and V is 0.3 to 30 mm, preferably 1 mm to 5 mm. Also, the height h of the protrusion should be set to 0.2 mm or more.
The thickness D of the sheet portion is 10 mm, preferably 0.3 mm to 3 mm, and the thickness D of the sheet portion is 0.2 to 3.0 mm, preferably 0.3 to 2.0 mm.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a cap according to the present invention. FIG. 2 is an enlarged perspective view of the dotted line portion a in FIG. 1. 3 and 4 are partially cutaway enlarged views of the outlet end face of the cap according to the present invention. 5 and 6 are partially cutaway vertical sectional views of the vicinity of the outlet end of the mouthpiece according to the present invention.

Claims (1)

[Claims] 1 Forming the slit in a foam sheet manufacturing die having an annular or linear slit on the outlet side 1
A large number of protrusions protruding toward the opposing wall are attached to the outlet ends of two walls, and both sides of the protrusions rising from the wall are substantially flat, and the width of the protrusions gradually increases along the direction in which the resin travels. Tilt it so that
A die for manufacturing a foam sheet having ridges on its surface, characterized by an included angle of 15 to 90 degrees between both sides.