JPS5822334B2 - Method for manufacturing thermoplastic film overlay concrete panels - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing concrete panels overlaid with thermoplastic films.

Conventional wood-based concrete panels had drawbacks such as discoloration of the wood by the cement alkali, which was transferred to the concrete surface, and special extracts from the wood that caused poor curing of the concrete.

In order to prevent this, we have checked each tree species for poor curing or pale color in the concrete, and selected wood species that do not cause these problems for use in concrete panels, but these species have limited resources, workability, and cost. It wasn't a very good approach.

Therefore, methods such as attaching a metal plate to the surface of various wooden boards, applying a thick coat of paint, or attaching a PVC film with adhesive have been used regardless of the type of wood. However, these had problems in terms of cost, alkali resistance, and durability of the control panel.

Therefore, the present inventors focused on a medium-low pressure polyethylene or polypropylene film that has excellent properties required for a composite panel, such as alkali resistance, hardness, and peelability from concrete.

However, it is difficult to adhere the film with adhesives commonly used in the industry, such as vinyl acetate emulsion and urea resin, and a strong bond cannot be obtained.

In view of these drawbacks, the present inventor conducted further studies and adopted a dry method of melting and pasting a film with similar properties in place of the conventional adhesive bonding method, the so-called wet method. We have completed a highly practical film overlay concrete panel.

In other words, in view of the various drawbacks of the conventional art, the present invention has been developed by placing a medium-low-pressure polyethylene or polypropylene film with a high softening point on the surface in contact with concrete, and applying high-pressure polyethylene or polypropylene film with a low softening point, which is generally said to have low alkali resistance. A polyethylene film is interposed between the base material and a medium-low pressure polyethylene film with a high softening point or a polypropylene film, and a polyethylene film with a softening point of at least the softening point of the high-pressure polyethylene film with a low softening point and below the softening point of the medium-low pressure polyethylene or polypropylene film with a high softening point. An unprecedented film overlay concrete panel was manufactured by heating at a high temperature to melt a high-pressure polyethylene film with a low softening point, and then bonding the substrate with a medium-low pressure polyethylene or polypropylene film with a high softening point.

Regarding the bonding conditions of the film, the film has a softening point and a melting point, and it is generally said that the softening point is about 5 to 10°C lower.

Therefore, the preferred bonding conditions are to laminate the substrate and both film layers at a temperature above the softening point of the film with a high softening point and below the melting point, and within a temperature range above the melting point of the film with a low softening point. If it is heated under pressure, its adhesion will be extremely strong.

Note that the substrate may be a wooden material such as plywood, a metal plate, a ceramic board, or the like.

Hereinafter, the present invention will be explained by way of an example.

A concrete panel plywood with a thickness of 12r11/rf1 is used as the substrate, and a high-pressure polyethylene film (thickness 50μ, melting temperature 130 to 140 ° C.) is placed on the substrate,
A low-pressure polyethylene film (thickness 50μ, melting temperature 150-160℃) was layered on top of it, and the pressing condition temperature was 140℃.
Heat and pressure adhesion is completed at a pressure of 15 kg/i for 90 seconds.

As described above, the present invention uses a high-pressure polyethylene film with a low softening point as an adhesive layer on a substrate such as plywood, and then applies hardness,
Since it is attached with a medium-low pressure polyethylene or polypropylene film that has excellent performance required for a component panel such as alkali resistance, the component panel's alkali resistance, frequent use resistance, and removability from concrete are far superior to conventional component panels. Are better.

Furthermore, the adhesive strength of the medium-low pressure polyethylene or polypropylene film is strong because it is heat-melted and bonded via a high-pressure polyethylene film with properties similar to the surface film, without using adhesives as in conventional methods. Not only that, but the film is overlaid on the substrate, so it looks like a conventional wooden concrete panel.
It has great effects, such as preventing discoloration of the woody part caused by the cement alkali and transferring it to the concrete surface, and preventing the special extracts from the woody part from causing poor hardening of the concrete.

Claims (1)

[Claims] 1. Place a high-pressure polyethylene film with a low softening point on a substrate, and then overlay a medium-low-pressure polyethylene film with a high softening point or a polypropylene film on top of it, and then heat-press them to form a high-pressure polyethylene film with a low softening point. A method for producing a thermoplastic film overlay concrete panel, which comprises melting the film and bonding the substrate to a medium-low pressure polyethylene or polypropylene film having a high softening point.