JPS6262725A - Processing of thermoplastic synthetic resin expansion-molded body - Google Patents

Abstract

PURPOSE:To eliminate the cleaning of a cast-in heater and at the same time give cushioning power to a product by a method wherein a sheet, which has a melting point higher than the melting temperature of resin mentioned below, is contactingly provided onto the surface of a thermoplastic synthetic resin expansion-molded part and the cast-in heater, which is heated up to a temperature higher than the melting temperature of the resin, is pressed through the sheet against the molded part. CONSTITUTION:Firstly, a sheet selected from paper, cloth and plastic sheets, which has a melting point higher than the melting temperature of resin mentioned below, is contactingly provided onto the surface of a thermoplastic synthetic resin expansion-molded body. Secondly, a cast-in heater, which has the predetermined shape and is heated up to a temperature higher than the melting temperature of the resin, is pressed from above the molded part in order to form a recess having the shape of the cast-in heater onto the molded part and, after that, the sheet is peeled off. Olefin resin such as polystyrene, polyethylene, resin expansion-molded body. A heater cast in aluminum, cast iron, brass or the like is employed as the cast-in heater. THe heater with a desired shape will do. Consequently, no resin adheres to the cast-in heater and the cleaning of the heater is eliminated. In addition, because of being foamed resin layer, the formed surface has cushioning power.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a method for processing a thermoplastic resin foam molded product, and more particularly, to a novel method for processing a thermoplastic synthetic resin foam molding using a casting heater. It is.

"Prior Art and Problems" Conventionally, boxes and packaging containers for light electrical equipment, PR-secure equipment, and their parts, etc., have been made using foamable synthetic resin particles such as polystyrene in the mold cavity between the cavity mold and the core mold. The method used is to heat and foam the foam using steam or the like, or to cut out a predetermined shape from a foam molded board, and then adhere it to another foam board.

However, when using the former molding method, the equipment is large-scale and therefore the equipment cost is high, making it unsuitable for meeting the demand for a wide variety of products in small quantities. Furthermore, the latter method requires complicated work and is not suitable for mass production, which inevitably results in a relatively high cost.

Additionally, since organic solvent-based adhesives are used, there is a risk of fire and explosion as well as being harmful to the human body.

On the other hand, in the case of relatively thin products, a manufacturing method using a casting heater has been proposed in recent years.

However, when manufacturing boxes, packaging containers, etc. from thermoplastic foam molded products such as polystyrene and polyethylene using cast heaters, the first problem is that resin adheres to the cast heaters. Usually, the surface of a cast-in heater is treated with a mold release agent such as Teflon (registered trademark) or other fluorocarbon resin, but during repeated molding, the resin gradually adheres to the surface, and cleaning is required periodically. is essential;
This results in a significant decrease in production efficiency.

Second, a hard molten resin layer is formed on the molding surface, so even if foamed synthetic resin, which has excellent warming properties, is used as a material, the inner surface of the container housing the important precision instruments and parts is In the hardened state, sufficient protection against impact cannot be expected, and there is a risk of damaging the stored items during transportation.

"Means for Solving the Problems" In view of the above circumstances, the present inventor has arrived at the present invention as a result of intensive research to solve the above problems.

That is, in the present invention, a sheet having a melting point higher than the melting temperature of the resin is attached to the surface of a thermoplastic synthetic resin foam molding, and then a casting heater having a predetermined shape is heated to a temperature higher than the melting temperature of the resin. A method for processing a thermoplastic synthetic resin foam molded article, characterized in that a concave portion in the shape of the cast heater is formed by pressing from above the sheet, and then the sheet is peeled off and removed. be.

As the thermoplastic synthetic resin foam molding used in the present invention, olefin resins such as polystyrene, polyethylene, and polypropylene are suitable.

The olefin resin may be crosslinked or non-crosslinked.

The cast-in heater used in the present invention is a heater made of cast aluminum, cast iron, brass, etc., and may have any desired shape.

The sheet used in the present invention is not particularly limited as long as it has a melting point higher than the melting temperature of the thermoplastic synthetic resin, but paper such as thin paper, Kyokagami paper, tissue paper, cotton,
Examples include cloths such as silk, synthetic fibers and gauze, synthetic resin films such as vinyl chloride and polyester, and plastic papers such as polystyrene and polyurethane.

In the present invention, the above-mentioned sheet is placed before a board or block of a thermoplastic synthetic resin foam molded product, and a casting heater of a desired shape is heated to a temperature higher than the melting temperature of the resin to press and cast the sheet from above. It may be allowed to settle due to the weight of the heater itself, or it may be pressed at an appropriate speed. The pressing speed depends on the type of resin, foaming (g rate), temperature of the casting heater, etc., and is appropriately determined in consideration of these factors.

When the molding is completed, the cast heater is removed and the sheet is then peeled off. The molten resin layer on the molding surface adheres to the sheet and is peeled off together with the sheet to reveal a layer of thermoplastic synthetic resin foam molding.

The sheet may be removed while the molding surface is still hot or after it has cooled, but it is preferable to peel and remove the sheet while the molding surface is still hot. However, it is also possible to leave the sheet on the molding surface if necessary. For example, if the sheet is a synthetic sealant film, leaving the sheet behind can impart waterproofness and gas barrier properties, and If the sheet is made of polystyrene heher or polyurethane foam paper, it is possible to provide appropriate cushioning properties.

By making the casting heater generally 2 to 3 fl smaller than the desired processing size (length x width x depth), it is possible to obtain an object of the desired processing size.

The present invention is suitable for relatively thin molded products with a molding depth of up to about 100 mm, and is suitable for surface embossing and character-printing of things such as mailboxes and packaging containers, as well as bath grates and kitchen mats.
It can also be applied to pasting etc.

"Examples" The present invention will be described below with reference to Examples, but the present invention is not limited to these in any way.

Example 1 Thin paper (made by Marubashira Paper Co., Ltd.) on a board of polystyrene foam "Styrofoam" (expansion ratio 50 times, made by Fukkasei Co., Ltd.)
was pressed onto the thin paper for about 25 seconds with a cast-in heater measuring 93 mm long x 48 mm thick heated to about 80"C.

Next, after removing the cast-in heater, the release agent was immediately removed from the thin paper. The molten resin adheres to the thin paper and is removed along with the thin paper, leaving approximately 200 fl x
A container with a medium size of 100 wm x a depth of 5 Qmm was obtained.

Example 2 Polypropylene foam "Be-block" (foaming ratio 4)
The thin paper used in the example was brought into contact with a board made of Nippon Styrene Paper (Japan Styrene Paper), heated to about 88° C. using the same casting heater as in Example 1, and pressed for about 30 seconds.

Next, the casting heater was removed and the molding surface was cooled, and then the thin paper was removed by f11. The molten resin layer on the molding surface was peeled off together with the thin paper, and the layer was approximately 200 layers long.
A container with a width of 100 mm x 50 fi was obtained.

“Action/Effect” As mentioned above, the present invention is: ■Equipment is simple and low cost;
■ Suitable for high-mix, low-volume production; ■ Applicable to all foamed plastics; ■ Since the molding surface is a foamed resin layer rather than a molten hardened resin layer, there is no reduction in heat capacity and the contents are It has many advantages such as being protected,
Its usefulness is extremely great.

Claims (1)

[Claims] 1. A sheet having a melting point higher than the melting temperature of the resin is attached to the surface of the thermoplastic synthetic resin foam molding, and then,
A cast-in heater of a predetermined shape is heated to a temperature higher than the melting temperature of the resin and pressed from above the sheet to form a concave portion in the shape of the cast-in heater, and then the sheet is peeled off and removed. Processing method for thermoplastic synthetic resin foam moldings. 2. The processing method according to claim 1, wherein the sheet is selected from paper, cloth and plastic sheets. 3. Thermoplastic synthetic resin is polystyrene, polyethylene,
The processing method according to claim 1, wherein the processing method is selected from polypropylene and polyurethane.