JPS5847335B2 - Netsukaso Seigou Seijyuushi Tono Shinkuusei Keihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for vacuum forming a thermoplastic synthetic resin sheet, and more specifically, for obtaining an efficient and good molded product when vacuum forming a thermoplastic synthetic resin sheet. This relates to a molding method.

Conventionally, when forming containers and the like using a vacuum forming method using a thermoplastic synthetic resin sheet as a raw material, the periphery of the thermoplastic synthetic resin sheet is attached to a clamp frame, etc., and the sheet is heated from above and below using an electric heater, etc. to soften it. After that, it is placed on a vacuum mold and molded by sucking air.

However, in such a vacuum forming method, when the thermoplastic synthetic resin sheet is heated by a heater, the synthetic resin sheet sag (drawdown) due to its own weight, and the softened thermoplastic synthetic resin sheet is heated by the heater below. It had a tendency to break when it came into contact with the mold or the vacuum mold.

An object of the present invention is to provide a method for solving the above-mentioned defects and obtaining a good molded product when vacuum forming a thermoplastic synthetic resin sheet,
The gist of this is a non-breathable sheet made of thermoplastic synthetic resin (hereinafter simply referred to as a non-breathable sheet).

) and a perforated sheet that does not undergo thermal deformation at the preheating temperature of the non-breathable sheet and has through-holes that communicate with the front and back sides, with the non-breathable sheet positioned on the side of the mold. A method for vacuum forming a thermoplastic synthetic resin sheet, the method comprising: heating the non-breathable sheet to a temperature higher than the heat deformation temperature of the non-breathable sheet, and vacuum forming only the non-breathable sheet along a mold. It exists in

The present invention will be explained in detail below.

In the present invention, vacuum forming refers to heating a non-porous sheet made of thermoplastic synthetic resin ("non-porous sheet") to a temperature higher than the heat distortion temperature using an appropriate means such as an electric heater, heated air, or a combustion furnace, and forming a female mold. The non-porous sheet is deformed and adhered to a male vacuum forming mold by suction from the mold side and/or compressed air from the opposite side of the mold to form a molded product in the desired shape. This is a molding method that

The non-breathable sheet used in the method of the present invention is made of styrene resin, olefin resin, vinyl chloride resin, polyamide, polycarbonate, or other thermoplastic synthetic resin formed into a sheet by extrusion molding or calendar molding. Things can be given.

These air-impermeable sheets may be foamed, partially crosslinked, or the like.

Specific examples of breathable (perforated) sheets include paper, metal foils such as aluminum foil and copper foil, nets made of thin metal wires, laminates of paper, metal foils, etc., and synthetic resins, Examples include thermosetting synthetic resin sheets and laminates thereof, and any material may be used as long as it does not undergo thermal deformation at the temperature at which the above-mentioned non-breathable sheet is preheated for vacuum forming. .

As long as the through holes provided allow air to flow in well during vacuum forming, the non-porous sheet will be sucked into the vacuum forming mold even if many fine through holes are provided throughout the sheet. A single hole may be provided at a location corresponding to a portion, and there is no need to drill holes in a sheet-like object made in advance.
The sheet-like material itself may be in the form of a net or non-woven fabric to provide air permeability.An example of implementing the method of the present invention will be explained in more detail with reference to the drawings, but the present invention will be described below unless it exceeds the gist thereof. The present invention is not limited to this embodiment.

Figures 1a and 1b are longitudinal cross-sectional views of a non-breathable sheet and a permeable (perforated) sheet used in the method of the present invention in a superimposed state, and Figure 2 is the same as that shown in Figure 1a. FIG. 3 is a longitudinal cross-sectional view of a portion of the sheet placed in a vacuum forming mold, FIG. 3 is a drawing similar to FIG. 2 after vacuum forming, and FIGS. 4 a and b are
FIG. 1 is a partially cutaway perspective view of an example of a product manufactured by the method of the present invention.

In the figure, 1 is a non-breathable sheet, 2 is a breathable sheet,
Reference numeral 3 indicates a through hole provided in the breathable sheet, 4 indicates a synthetic resin coating coated on the breathable sheet 2, 5 indicates a vacuum molding mold, 6 indicates an air suction conduit, and 7 and 8 indicate clamps, respectively.

The non-breathable sheet, as illustrated in FIG. Overlap.

The two stacked sheets are heated to a temperature equal to or higher than the thermal deformation temperature of the non-porous sheet 1 by a heating mechanism such as an electric heater heating furnace, as is generally known in vacuum forming technology.

At this temperature, if the air-permeable sheet 2, which does not cause thermal deformation, is placed on the lower side and heated, the non-air-permeable sheet 1 placed on top of the air-permeable sheet will be thermally deformed and cause drawdown. Even if it does, it is supported by the lower breathable sheet and does not sag, which is preferable.

Depending on the product, it is also possible to perform molding with the non-breathable sheet 1 at the bottom, but in this case, the non-breathable sheet 1 and the breathable sheet 2 may be partially laminated together. This prevents drawdown of the non-air permeable sheet during heating.

In addition, when obtaining a large number of container-like objects from a single non-porous sheet, or when providing a large number of protrusions, the parts that will not be vacuum-formed should be clamped using a clamp frame, etc., and then heated. Alternatively, it may be clamped using a clamp frame or the like after heating.

The two heated sheets are guided to a predetermined position in a vacuum forming mold 50 as shown in FIG. As shown in FIG. 3, the air-impermeable sheet 1 is deformed by adsorption along the inner surface of the cavity of the mold 5, and is molded into a desired shape.

At this time, air is introduced through the through holes of the breathable sheet 2.

In addition, during this molding, the non-ventilated sheet 1 may be brought into close contact with the mold 5 by blowing air through the through holes 3 from the ventilated sheet 2 side, or both may be molded. Of course, they may be used in combination.

The molded product thus obtained consists of a non-breathable sheet 1 molded into a hollow shape and a breathable sheet 2 which remains flat, and the two may be separated and used after molding.

FIG. 4a is a perspective view of a container vacuum-formed by the method of the present invention with a breathable sheet superimposed on it, and FIG. 4a is a modified example of the molded product by the method of the present invention; This is a box-shaped container using the molded portion of the sheet 1 as a cushioning material.

According to the method of the present invention, the non-breathable sheet 1 and the breathable sheet 2 are overlapped and heated, so it is possible to prevent the non-breathable sheet 1 from drawing down during heating.

Therefore, the heated non-air permeable sheet 1 will not come into contact with a heating heater, a mold, etc. and break.

In addition, during heating, the non-porous sheet made of thermoplastic synthetic resin can be easily held horizontally against the heating heater, so heating is done evenly, and the heating heater etc. is also made of non-porous thermoplastic synthetic resin. It can be provided close to the sheet, and therefore heating can be performed efficiently.

In addition, when the obtained molded product is combined with a breathable sheet, the strength of the molded product becomes excellent, and if the structure shown in Figure 4 a and b is used, it can be used for containers with lids, cushioning materials, etc. Molded articles can be produced very easily.

Therefore, the industrial utility value of the method of the present invention is extremely limited.

[Brief explanation of the drawing]

FIG. 1 FAtb is a vertical cross-sectional view of a non-breathable sheet made of thermoplastic synthetic resin used in the method of the present invention and a breathable sheet superimposed, and FIG. 2 is a longitudinal cross-sectional view of a state shown in FIG. FIG. 3 is a longitudinal sectional view of a portion of the sheet when it is placed in a vacuum forming mold, and FIG. 3 is a drawing similar to FIG. 2 after vacuum forming.
FIGS. 4a and 4b are perspective views cut at - and H3 of an example of a product manufactured by the method of the present invention. 1 is a non-breathable sheet made of thermoplastic synthetic resin, 2 is a breathable sheet, 3 is a through hole provided in the breathable sheet, 4 is a synthetic resin film applied to the surface of the breathable sheet 20, 5 is a vacuum molding mold , 6 indicates an air suction conduit, and 7.8 indicates a clamp, respectively.

Claims (1)

[Scope of Claims] 1. A non-breathable sheet made of thermoplastic synthetic resin (hereinafter simply referred to as non-breathable sheet), which does not undergo thermal deformation at the preheating temperature of the non-breathable sheet, and which communicates between the front and back sides. A perforated sheet having through-holes is placed on top of the other with the non-breathable sheet positioned on the side of the mold, and heated to a temperature higher than the heat deformation temperature of the non-breathable sheet to form the non-breathable sheet. A method for vacuum forming a thermoplastic synthetic resin sheet, characterized by vacuum forming only the sheet along a mold.