JPS629081Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the improvement of a composite sheet made of a foamed polyolefin insheet, and in particular, to obtain a shoe insole material with excellent cushioning properties.

Conventionally, insole materials for shoes have been made of composite sheets made of plastic foam with fibers such as pile attached, which are punched into the shape of the foot.

In order to impart appropriate cushioning properties to insole materials, the base material is a composite sheet made of a combination of foams with different expansion ratios, a fiber layer such as pile on the surface, and a layer of fibers such as pile in the middle. The cushion layer is made of a high-magnification foam, and the back side is made of a low-magnification foam as a core material.

In order to create a shape that fits the sole of the foot, the sheet is made of a uniform thickness and is made thinner at the toe area and thicker at the heel area. The method for performing this undulating process is mainly the air pressure thermoforming method. As for this material, polyolefin foam, particularly polyethylene foam, is used because it has excellent thermoformability and cushioning properties.

However, insole materials are required to have a wall thickness ratio of 1:2 to 5 between the toe section and the heel section, but when processing and compressing the composite material with the above uniform thickness, However, it was not possible to mold an insole material having the above-mentioned ratio and having excellent cushioning properties.

The reason for this is that the toe area is strongly compressed to make it thin, so most of the bubbles in the composite sheet in this area collapse and the gas inside the bubbles escapes, but this gas does not completely escape to the outside. It penetrates into the seam between the high-magnification foam and the low-magnification foam of the composite sheet, peels off the adhesive interface in this area, and spreads it out to form a cavity. This cavity is particularly likely to occur in the heel. These cavities significantly impede the cushioning properties of the heel region, degrading its performance as an insole material.

As a result of intensive research aimed at improving these drawbacks, the present invention has resulted in the discovery of a composite sheet that has excellent cushioning properties and is particularly suitable for shoe insoles, without forming cavities in the heel area or in that area. It is something that That is, the present invention involves pasting a foamed polyolefin sheet with a foaming ratio lower than that of the foamed polyolefin sheet on one side and having through holes of 500 or more/m ² , and preferably a woven or nonwoven fabric on the other side. This is what I wore.

In the present invention, the reason why the polyolefin foam sheet with a low expansion ratio is penetrated with a large number of small holes is that the gas released from the bubbles of the polyolefin foam sheet with a high expansion ratio after compression molding is allowed to escape to the outside through the small holes. And even more preferably,
After the gas is completely expelled, a part of the polyolefin foam sheet with a high expansion ratio moves through the small pores, and the molded product is formed by penetrating into the exit of the small hole. The adhesion with the polyolefin foam sheet with the expansion ratio becomes even stronger due to the anchoring effect.

Therefore, in order to quickly escape the air generated by compression to the outside, 500 pieces/m2 ^or more is required.
Desirably it is 1000 to 50000 pieces/ ^m2 . 500 pieces/ ^m2
If it is less than that, air tends to become trapped inside the sheet, making it impossible to maintain excellent cushioning properties.

The size of the small hole is not particularly limited, but it is preferably 5 mmφ or less in diameter.
Preferably, the diameter is 0.5 mmφ to 2.0 mmφ.

In the present invention, the foamed polyolefin sheet is, for example, a crosslinked or non-crosslinked foamed polyethylene sheet or a foamed polypropylene sheet, and the foaming ratio of the low foamed polyolefin sheet is 5 to 10 times, and the thickness is 2.
~4 mm, the foaming ratio of the highly foamed polyolefin sheet is 15 to 30 times, and the thickness is 4 to 10 mm.

In the present invention, preferably, a woven fabric or non-woven fabric is provided on the surface to impart a pleasant feel to the skin, and pile is usually used for this purpose.

Next, embodiments of the present invention will be described based on the drawings.

Example (1) As shown in Figure 1, on one side of a cross-linked foamed polyethylene sheet 1 with an expansion ratio of 20 times and a thickness of 6 mm,
A cross-linked foamed polyethylene sheet 2 with a thickness of 2 mm and a foaming ratio of 8 times, in which small through holes 3 of mmφ are bored at 5 mm intervals (40,000 holes/m ² ), is pasted, and a pile 4 is pasted on the other side. I devised a composite sheet.

After heating this sheet in a constant-temperature heating oven at approximately 150°C for 1 minute, it was sandwiched between molds for insole materials and air-formed so that the toe part was 2 mm thick and the heel part was 6 mm thick. I did the bedding. As shown in FIG. 2, a partially enlarged cross-sectional view of the insole material thus obtained, the first part 5 of the cross-linked foamed polyethylene sheet 1, after expelling the gas, sinks into the small pores and forms the cross-linked foamed sheet 2 with a low expansion ratio. It reaches the outer surface. As described above, the insole material had no cavities at all and had excellent cushioning properties.

Example (2) A 5 mm through-hole with a diameter of 0.5 mmφ was formed on one side of a cross-linked foamed polypropylene sheet with an expansion ratio of 30 times and a thickness of 5 mm.
Foaming ratio 10 with holes drilled at intervals (40000 holes/m ² )
A cross-linked foamed polypropylene sheet with a thickness of 3 mm was attached, and a pile was attached to the cured surface to obtain a composite sheet of the present invention.

After heating this composite sheet for 2 minutes in a constant-temperature heating oven at approximately 180°C, it was sandwiched between molds for shoe insoles so that the toe part was 2 mm thick and the heel part was 6 mm thick, and then air-formed into shoes. I got the insole material.

This insole material had no cavities and had excellent cushioning properties.

As described in detail above, the present invention has remarkable effects such as producing a molded product with excellent cushioning properties that does not create any voids inside even when different compressive forces are applied to desired locations.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of the composite sheet of the present invention, and FIG. 2 is a partially enlarged sectional view for explaining the state of the composite sheet of FIG. 1 after compression molding. 1... High expansion ratio polyethylene sheet, 2...
Low expansion ratio polyethylene sheet, 3...Small holes, 4
……pile.

Claims (1)

[Scope of utility model registration request] 1. A composite sheet comprising a polyolefin insheet having a high expansion ratio and a foamed polyolefin sheet having a lower expansion ratio than the sheet and having through holes of 500 or more/m ² attached to one side of the polyolefin sheet.