JPS6021051B2 - Heating method for composite sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a composite sheet made by laminating a relatively thin leather sheet made of polyvinyl chloride or the like and a relatively thick foam sheet made of polypropylene foam or the like one above the other. It relates to a heating method used to heat a material to near its softening temperature in preparation for, for example, drawing processing.

Conventional heating methods for this type of sheet include preparing the sheet held by the left and right ears and heating it from the upper and lower surfaces using electric or other heaters, or by further heating the sheet with hot air. In such a method, the temperature of the upper layer of the discussion sheet rises relatively far, but the temperature of the lower layer of the foam sheet rises only at the bottom surface, and there is a gap between the inside and the inside of the foam sheet. In other words, it is difficult to uniformly raise the temperature of the entire product, which causes the inconvenience that the product is likely to have non-uniform wall thickness due to non-uniform elongation when drawing, for example. Accompany. In order to eliminate the above-mentioned disadvantages, attempts have been made to, for example, provide a temperature difference between the upper and lower heaters, but good results have not always been obtained.

It is an object of the present invention to provide a heating method that does not cause such inconveniences. Prior to drawing, the composite sheet, which is made by pasting the two sheets vertically together, is heated to approximately 100 qo on the leather sheet side and approximately 80 qo on the foam sheet side.
The temperature was raised at 0:00 pm, and then auxiliary heating was performed to approximately 100oC to 11
It is characterized in that it is maintained at a soaking temperature of 000°C and then further heated to 150°C to 160qC on the leather sheet side and 1300°C to 140°C on the foam sheet side by secondary heating, and then used for molding.

An example of implementing the present invention will be explained with reference to the attached drawings. In the drawing, 1 designates a composite sheet to be heated, which sheet 1 is e.g.
As clearly shown in the figure, it is constructed by laminating a relatively thin leather sheet 2 made of polyvinyl chloride and a relatively thick foam sheet 3 made of polypropylene foam one above the other. The sheet 1 is heated to raise its temperature to near its softening temperature in preparation for drawing, for example. According to the present invention, the sheet 1 is heated first by primary heating and then uniformly heated. After the heat treatment, the temperature was further increased by secondary heating.

To explain this in detail, the sheet 1 is placed in the first position as shown in the second figure.
The sheet 1 is sequentially passed through a zone 4, a second zone 5, and a third zone 6. In the first zone 4, the sheet 1 is heated by upper and lower heaters 7, 7. It is assumed that the temperature on the side of the sheet 3 is raised to about 100°C and the side of the sheet 3 to about 80°C, and then the sheet is subjected to only hot air of, for example, 100 to 11,000 in the second zone 5 to equalize the temperature therein. In other words, the sheet is subjected to soaking treatment in the zone 5 so that the sheet 2 side and the sheet 3 side are at approximately the same temperature, for example, at about 100 pm.
, and then the sheet 1 is placed in the third zone 6.
, the heating by the upper and lower heaters 8 and 8 further raises the temperature as a whole, for example, 1 on the sheet 2 side.
50-160q○ and 130-140 on the seat 3 side
The temperature was raised to oo.

The state of this temperature change is clearly shown in FIG. 3, where the solid line curve a shows the temperature change on the sheet 2 side, and the dotted line curve b shows the temperature change on the sheet 3 side. As described above, in the case of the present invention, the composite sheet is heated to approximately 100° C. on the leather sheet side and approximately 80° C. on the foam sheet side through primary heating prior to drawing, so rapid heating is not necessary. The foam sheet side, whose structure is easily changed, can be heated together with the foam sheet side without damaging the structure, and then auxiliary heating is performed to approximately 100qo to 110qo.
Since the foam sheet side was kept at the same temperature as the leather sheet side without being thermally damaged, the leather sheet side was heated to 150℃ by secondary heating.
0C~160pm, foam sheet side 13000~1
Since it is heated to 40°C and subjected to draw forming, the elongation rates of the leather sheet side and the foam sheet side, which have different elongation rates at high temperatures that can be formed, must be the same depending on the temperature difference. This has the effect of making it possible to obtain an excellent product without generating moisture when drawing a composite sheet.

[Brief explanation of the drawing]

Fig. 1 is a cut side view of an example of a composite sheet to which the method of the present invention is applied, Fig. 2 is an explanatory diagram of an example of the method of the present invention, and Fig. 3 is a diagram of an example of temperature change of the sheet. It is. 1... Composite sheet, 2... Leather sheet, 3... Foam sheet, 4... First
Zone, 5...2nd zone, 6...3rd zone. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 A composite sheet made by laminating a relatively thin leather sheet made of polyvinyl chloride etc. and a relatively thick foam sheet made of polypropylene foam etc. one above the other,
Prior to drawing and forming, the leather sheet side is heated to about 1
00℃, the foam sheet side was heated to approximately 80℃, and then auxiliary heating was performed to maintain the soaking temperature of approximately 100℃ to 110℃, and the leather sheet side was heated to 150℃ to 160℃ by secondary heating.
A method for heating a composite sheet, characterized in that the temperature of the foam sheet side is further raised to 130 to 140 degrees Celsius and subjected to molding.