JPS61261529A - Manufacture of plastic-covered steel sheet pile - Google Patents

Abstract

PURPOSE:To obtain a steel ceiling plate excellent in corrosion resistance and durability by bonding a laminate sheet consisting of a heat-resistant sheet, a thermoplastic sheet, and a thermoplastic adhesive sheet to the steel ceiling plate under a condition that the thermpolastic adhesive sheet in molten state. CONSTITUTION:A laminate sheet is formed by laminating a thermoplastic adhesive sheet I made of a polyolefin-acrylic acid copolymer, a thermoplastic sheet 2 made of a polyolefinic plastic material having a higher melting point than the said copolymer, and a heat-resistant sheet 3 of silicon rubber, etc. The laminate sheet is heated to nearly melting point of the plastic sheet 2 by a preheater 5 and a heater 6 while sending the laminate sheets in order and pressingly contacted with the curved faces of a steel sheet pile by a presser 7, whereupon the laminate sheet is hot-bonded to the curved faces by molten thermoplastic adhesive plastic sheet 1. Plastic-covered steel sheet piles having excellent corrosion resistance and excellent durability can thus be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a plastic coating yI1 for steel sheet piles used in civil engineering and construction work, which is highly corrosion resistant, durable, and economical. The present invention relates to a method for efficiently manufacturing excellent corrosion-resistant steel sheet piles.

[Conventional technology]

Steel sheet piles are widely used for civil engineering and construction work, such as bank protection on rivers, beaches, etc., and prevention of mixed piles flowing in and out at construction sites.

By the way, the environment in which steel sheet piles are used is constantly exposed to corrosive factors such as water, oxygen (air), and ultraviolet rays, and since steel sheet piles are expected to be used for a long period of time, it is difficult to establish corrosion prevention methods or technologies. was strongly desired.

[Problem that the invention seeks to solve]

In response to these demands, the conventional corrosion prevention methods are:
The main products were thermoplastic coatings such as tar and epoxy resins, and FRP coatings.

However, in the former case, there are problems with the mechanical strength of the coating, long-term corrosion resistance, or painting workability, and with the latter, there are still points that need to be improved in terms of workability and economic efficiency. It was something that

In recent years, there is a coated steel sheet pile that is expected to have high corrosion resistance, durability, and economic efficiency, and is made by heat-bonding thermoplastic plastic sheets extruded with T dies. It is extremely difficult to coat the uneven surface of steel sheet piles due to heat shrinkage and wrinkles that occur when the sheets are heat-bonded, and there is a strong desire to develop a coating method that is more perfect and easier to apply. was.

[Means for solving problems]

The present invention was arrived at as a result of various studies on a method for manufacturing steel sheet piles that overcomes the various drawbacks found in the conventional methods, and is based on a thermoplastic adhesive plastic (A) and its material. Thermoplastics with high melting points (
In press-bonding a single-layer sheet consisting of B) to a steel sheet pile, a heat-resistant sheet is layered on the B side of the laminated sheet, heated to the melting point of B, and the A side of the laminated sheet is directed toward the steel sheet pile side. Plastic-coated steel sheet piles are made of plastic-coated steel sheet piles that are made by stacking them on the same surface, holding the entire body above the melting point of B and bonding under pressure to integrate the laminated sheet and steel sheet piles, and removing the heat-resistant sheet during or after cooling. This relates to a manufacturing method.

[For production]

The thermoplastic adhesive plastic (A) is intended to achieve complete or sufficient adhesion between the steel sheet pile, which is the main body, and the anticorrosive coating layer.

In order to fully achieve this purpose, for example, polyolefin plastics graft-modified with carboxylic acid or its acid anhydride, or copolymers of polyolefin plastics and acrylic acid or derivatives thereof, etc. are used. be able to.

Any thermoplastic plastic (B) can be used as long as it can be coated on steel sheet piles and exhibits a long-term anti-corrosion effect, but the most common reason is that it is easily available. It is convenient to use polyolefin plastics.

A heat-resistant sheet is applied to the - side of the thermoplastic (B).

The functions required of this sheet are not only that it is stable against heat, but also that it does not soften or decompose even when exposed to temperatures near the melting point of thermoplastics.
Further, it is preferable that the material has good releasability.

As a material having such characteristics, for example, a thin film or paper of a heat-resistant elastomer such as silicone rubber or fluororubber or a high-melting point thermoplastic such as polyethylene terephthalate is used.

Hereinafter, the present invention will be further explained in detail using the drawings.

FIG. 1 shows a case in which a heat-resistant sheet 3 is further applied to a thermoplastic adhesive plastic 1 and a thermoplastic 2 polymerized together.

The thermoplastic adhesive plastic 1 and the thermoplastic plastic 2 may be formed by simultaneously melting and extruding each plastic in a laminated state using an extruder equipped with a T die, or alternatively, each sheet may be formed by melting and extruding each plastic at the same time using an extruder equipped with a T-die. They may be bonded together in the process of.

Figure 2 shows how steel sheet piles are constructed using the materials shown in Figure 1.
In order to firmly bond the steel sheet pile 4 and the thermoplastic adhesive plastic 1, it is better to heat the steel sheet pile to a temperature higher than the melting temperature in advance. It's easy to get caught.

Furthermore, it is also effective to perform brimer treatment on the steel sheet piles in advance, if necessary.

FIG. 3 shows an example of implementing the manufacturing method of the present invention.

In the figure, 5 is a preheater, 6 is a heating machine, 7 is a compression bonding device, and 8 is a cooling device.

The thermoplastic adhesive plastic 1, the thermoplastic plastic 2, and the heat-resistant sheet 3 are first heated in a preheater 5 to at least close to the melting point of the thermoplastic plastic (as shown in the figure), and then the steel sheet pile 4 is supplied. He is sent to the route, where the two come into contact.

The laminated sheet is spread out on the steel sheet pile 4 and then heated to the next heating machine 6.
(For example, an induction heating machine or a burner may be used) to supply heat until the thermoplastic plastic is sufficiently melted.

Next, when the laminated sheet is sent to a rolling device 7, it is brought into close contact with rollers or the like so as to match the curve of the steel sheet pile, and finally it is cooled in a cooler 8.

Among the rolls in the roll device 7, those for treating the surface of the steel sheet piles may have basic shapes as shown in FIGS. 4 to 7, for example.

Figures 4 and 5 are for crimping flat parts, Figure 6 is for processing curved surfaces at the ends of steel sheet piles, and Figure 7 is for crimping inner corners. This is an example.

Although not shown in the figure, the heat-resistant sheet is peeled off during or after the cooling operation in the cooler 8.

〔Example〕

Hereinafter, the structure and effects of the present invention will be explained by specifically showing examples.

An experiment was conducted in which a 7 m long middle portion of a 12 m long U-shaped steel sheet pile (NKSP-IA, manufactured by Nippon Kokan Co., Ltd.) was coated with plastic.

A Thermoplastic adhesive plastic Maleic acid graft copolymerized polyethylene (melting point 125°C) B Thermoplastic plastic High-density polyethylene (melting point 133°C) Sheet conditions A and B each have a thickness of 0.2 and 2.0-,
Two layers were extruded using a T die to form a sheet with a diameter of 75c111 and a length of 8m.

After sandblasting, a reaction-curing epoxy primer (approximately 50 μm) was applied and cured.

1 item 1 property "-2" - Silicone rubber filled with silica fine powder was used. The size of the sheet is 80 cIn x 8, 5 m x 1 -.

The myuu trap laminated sheet was superimposed on the #4 thermal sheet and heated to 140°C (140°C) using a heat roll, and then attached to the concave side of a steel sheet pile that had been previously heated to 150°C. The steel sheet piles were curved in advance to a smaller curvature than the concave surface of the steel sheet piles, and then crimped in order using rolls as shown in FIGS. 4 to 7.

Thereafter, the whole was cooled to room temperature by water cooling, the heat-resistant sheet was removed, the edges were adjusted, and a predetermined coating was formed.

When the polyethylene S steel sheet pile manufactured by the above method was examined, no lifting, wrinkles, or scratches were observed in the coating, and the peel strength at 23°C was 17 kg/10 aw.
It was confirmed that it was firmly adhered to the a width.

On the other hand, when the heat-resistant sheet was not used, when the exact same process was repeated, random shrinkage occurred in the length direction after heating the laminated sheet.
Wrinkles were generated, and after the mouth-to-mouth crimping, both ends were curled up and were hardly bonded.

〔Effect of the invention〕

The plastic steel sheet pile obtained according to the present invention has extremely high corrosion resistance, has poor durability, and is also excellent from an economical point of view because it is easy to manufacture.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a laminated sheet according to the present invention, Fig. 2 is a sectional view of a plastic steel sheet pile, Fig. 3 is a schematic diagram illustrating a method for manufacturing a plastic steel sheet pile, and Figs. 4 to 7 are for crimping. FIG. 3 is a partial cross-sectional view illustrating types of rollers and situations in which they are used. 1... Thermoplastic adhesive plastic, 2... Thermoplastic plastic, 3... Heat resistant sheet, 4 Steel sheet pile, 5
... Preheater, 6... Heating machine, 7. Crimping device, 8...
Cooling system. −

Claims (1)

[Claims] When press-bonding a laminated sheet consisting of a thermoplastic adhesive plastic (A) and a thermoplastic plastic (B) with a higher melting point to a steel sheet pile, a heat-resistant sheet is layered on the B side of the laminated sheet until the melting point of B is reached. Heat the laminated sheet A
The laminate sheet and the steel sheet pile are overlapped on the specified surface with the surface facing the steel sheet pile side, and the whole is held above the melting point of B and bonded under pressure to integrate the laminated sheet and the steel sheet pile. A method of manufacturing plastic-coated steel sheet piles consisting of removing the sheets.