JPS5828355A - Manufacture of low foamable thick plate - Google Patents

Abstract

PURPOSE:To obtain a low foamable thick plate which has a desired thickness and large mechanical strength with a simple facility by inserting a sheetlike conductor between laminated plates stacked with low foamable plastic sole plates, flowing a current, heating the conductor, thereby integrally coupling them. CONSTITUTION:Low foamable plastic sold plates which are foamed to become the prescribed specific weight, for example, with 2-4mm. thick are stacked in number in the total thickness to the prescribed thickness. Sheetlike conductors such as metal gauzes, carbon fiber fabrics, conductor-mixed plastic films or the like are inserted between the plates, thereby maintaining the thickness constant. Then, a current is flowed from terminals provided at both sides, thereby causing Joule heat generated at the conductors to be interrupted by the plates of thermally non-conductive conductors and the temperature to be raised, thereby melting the adjoining plates to fusion-bond the plates. After cooling, the plates can be rigidly integrated, thereby obtaining a target low foamable laminated thick plate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for industrially manufacturing low-foam plastic planks using simple equipment.

In the past, wood and other materials were used as materials for construction, civil engineering, etc., such as concrete panels and scaffolding.
It has been desired that a material with excellent water resistance, acid resistance, alkali resistance, etc. and a long lifespan can be produced at low cost.

However, polyethylene and polypropylene were used in 9 cases.

It is difficult to manufacture low-foam plate-like molded products such as polyvinyl chloride and ABS resin, that is, products with a specific gravity of about 0.4 to 0.7, a thickness of 10 or more parts, and a uniform air bubble distribution, using conventional methods. In the foam press molding method, it is difficult to achieve product homogeneity with non-crosslinking methods such as the monodegradable blowing agent method, volatile blowing agent method, and gaseous blowing agent method due to poor temperature distribution, etc., and electron irradiation. Cross-linking methods such as the peroxide method and the peroxide method are unsuitable for producing low-foam boards.

The present invention overcomes the drawbacks of the conventional manufacturing method as described above, and makes it possible to manufacture low-foam plastic plates with desired thickness and high mechanical strength by a new industrial method using simple equipment. It was done for a purpose.

That is, the present invention can be carried out in advance by an extrusion foam molding method, for example, a commonly used method. Two examples of homogeneous low-foam plastic plates manufactured using a bi-degradable blowing agent, azodicarbonamide,
Dinitrosopentamethylenetetramine, 4,4oxybisbenzenesulfonylhydrazide, azobisinbutyronitrile, toluenesulfonyl 1. The aim is to produce homogeneous, low-foam thick plates by laminating low-foam polyethylene, etc., with a thickness of 2 to 4 mm, manufactured by extrusion foam molding using hydrazide, etc. However, stacking them as they are and heating and pressurizing them will bring them to an extremely ideal state, and the area near the heating surface will become more fluid, and by applying pressure, air bubbles will be removed. This causes loss and movement of bubbles, and it is difficult to manufacture a thick plate with a homogeneous bubble distribution.

On the other hand, it may be possible to use adhesives to bond these laminated layers together, but this would not only be difficult to operate and create a poor working environment, but also 2% polyethylene, polypropylene, etc. , there are no effective and practical adhesives in sight.

According to this invention. The low-foam plate manufacturing method allows each laminated veneer to be processed without changing its specific gravity, air bubble distribution, etc.
It is completely welded using simple equipment and operation, making it possible to mass-produce excellent low-foam thick plates in practical terms.

That is, one example of foam molding to obtain a desired specific gravity is 2.
-4■ veneers: Stack the number of veneers so that the total thickness is the desired thickness, and stack them between each low-foam veneer.

9. Metal mesh and carbon fiber fabric are used for the two sheet-like conductors. By stretching a conductor-mixed plastic film, etc., and passing current through terminals provided on both sides while keeping the thickness constant, μZeal heat is not generated in the conductor.

, the temperature rises due to being blocked by the low foam veneer, which is a poor thermal conductor, and the adjacent low foam veneers are melted and each veneer is welded, and after a power outage and cooling, they are tightly integrated into one. It is possible to produce a low-foam laminated thick plate with low foaming.The present invention will be specifically explained below based on an example in which a polyethylene resin is used.

Example 1 Polyethylene (medium density, specific gravity 0.935) 100 parts Decidicarbonamide 0.7 part Temperature
A low foam veneer with a thickness of 3cm (90zX1
80cfR) (specific gravity 0.58), stacked 4 veneers, stretched iron wire mesh (so-called lath mesh) between each veneer, fixed the thickness, and used brush-like terminals from both sides. Current (Ac
t 100V) for 30 seconds and cooled. 1. Completely adhered to one piece. Thickness: 127. Specific gravity: 0.60. A completely flat, low-foamed polyethylene film with excellent peel strength between laminated layers was obtained.

Example 2 Polyethylene (low density, specific gravity 0.92) 100 parts Azoshika, Rubonamide 0.75 parts Temperature
180℃ residence time 5 minutes extrusion molding method,
Low foam veneer with a thickness of 2.5cm and a specific gravity of 0.60 (90cm
, 180m), stacked 4 veneers, and placed between each veneer,
A polyethylene (ratio jiO, 92) film (thickness 0.03cm) prepared by kneading and molding graphite powder with a weight ratio of 1 inch was stretched,
While keeping the thickness of the metal constant, a current (Act 100'V) was applied for 1 minute, and the metal was allowed to cool, with a specific gravity of 0.62. We obtained a low-foamed polyethylene thick plate with a peel resistance of 9 and a mechanical strength of 9 and a thickness of 10 mm and no deformation such as warping. Regarding current: either direct current or alternating current is acceptable, and especially frequency This is achieved by preparing a multi-stage frame and making the intervals between each stage plate constant, and it is possible to turn off the current and continue cooling, which eliminates the need for investment in special table equipment. As mentioned above, it also prevents deformation such as warping of the product.
This invention has been difficult to achieve in the past. Light weight, uniform bubble distribution,
Therefore, we have completed a new industrial method for manufacturing low-foam plastic plates with high mechanical strength using simple equipment and simple operations, and which are desirable for use in concrete panels, construction scaffolding, etc., and are weather resistant. We use inexpensive raw materials (
It is also possible to use recycled raw materials).

Claims (3)

[Claims] (1) Stacking two or more low-foam plastic veneers and inserting a sheet-like conductor between each laminate to prevent expansion of the thickness, while connecting terminals on both sides to conduct current. A method for manufacturing low-foam thick plates that uses Geel heat to bond them together. (2) A method for manufacturing a low-foam thick plate according to claim 1, characterized in that a metal mesh is used as a conductor. (3) A plastic film made by kneading and molding conductor powder such as metal powder or carbon powder into a plastic material having the same composition or compatibility when heated as the low-foam veneer to be laminated is used as the conductor. A method for manufacturing a low-foam thick plate according to claim 1.