JPH07329242A - Piping material - Google Patents

Abstract

PURPOSE:To obtain a piping material good in heat resistance, fire retardancy and appearance by providing a resin coating layer using fluoroplastic with a combustion heating value of a specific value or less as a base material and having a film thickness of a specific value range to the outer periphery of a steel pipe. CONSTITUTION:A resin coating layer 2 with a film thickness of 10-1000mum using fluoroplastic with a combustion heating value of 3000cal/g or less, for example, a tetrafluoroethylene resin as a base material is provided to the outer periphery of a steel pipe 1. When the film thickness is below 10mum, uniform coating is difficult and the exposure possibility of the steel pipe 1 is large when the coated steel pipe receives mechanical external force. When the film thickness is made larger than 1000mum, economical efficiency is not obtained and a coating method is restricted only to an extrusion coating method. As the coating method of the steel pipe 1, an extrusion coating method, a powder coating application method, a heat-shrinking method of a shape memory tube and a coating application are possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant, flame-retardant and aesthetically pleasing piping material suitable for kitchen piping and the like.

[0002]

2. Description of the Related Art Conventionally, galvanized steel pipe has been used as a piping material used around kitchens. However, there is a problem that the galvanized surface has a single color tone and there is uneven color, and a beautiful piping material has been demanded.

Therefore, as piping materials having a more beautiful appearance, a vinyl chloride-coated steel pipe having vinyl chloride coated on its outer peripheral surface and a polyethylene-coated steel pipe having polyethylene coated on its outer peripheral surface have been developed.

[0004]

However, since the kitchen piping locally reaches a high temperature of 20 ° C. or higher and the vinyl chloride-coated steel pipe has a low heat resistant temperature of vinyl chloride, vinyl chloride deteriorates when used in the kitchen piping. There is a problem that it does. Further, polyethylene-coated steel pipes also have a problem that they cannot be used in the fireproof penetration section because they have a low heat resistance temperature like vinyl chloride and have no self-extinguishing property.

An object of the present invention is to solve these problems and to provide a piping material having good heat resistance, flame retardancy and good appearance.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the calorific value of combustion is 3000 cal /
It was found that if it is larger than g, the combustibility becomes a problem for the kitchen piping. Therefore, if the calorific value of combustion is 3000 cal / g or less, 2
As a result of searching various materials having a heat resistance of 00 ° C. or higher and suitable for coating a steel pipe, the inventors have found that a specific fluororesin is suitable for this purpose, and completed the present invention.

That is, according to the present invention, the outer circumference of a steel pipe is made of a fluororesin having a calorific value of combustion of 3000 cal / g or less
The present invention relates to a piping material provided with a resin coating layer of 10 to 1000 μm.

Fluorine resin has a calorific value of combustion of 3000 cal / g or less, preferably 2500 cal / g or less, and particularly preferably 2000 c.
It is al / g or less. This fluororesin has a fluorine content of 40
~ 80% by weight, preferably about 60-80% by weight, C-F
The bond is 40 mol% or more, preferably 60 mol% or more, and specific examples thereof include tetrafluoroethylene (PTFE) resin, perfluoroalkoxy (PFA) resin, and fluorinated ethylene propylene (FEP) resin.

In order to improve the adhesion to the steel pipe, these resins contain polyimide, polyether sulfide (PES), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), etc. within the range of not impairing their performance. Can be added or copolymerized. In addition, coloring agents for coloring within the range that does not impair its performance, and if necessary, addition of inorganic fillers, modifiers, dispersants, leveling agents, anti-settling agents, antioxidants, ultraviolet absorbers, etc. Agents can be added.

In any case, it is necessary that the resin coating layer contains the above-mentioned fluororesin in an amount of 30% by weight or more, preferably 50% by weight or more.

The coating thickness is 10 to 1000 μm, preferably 10 to 500 μm, and particularly preferably 20 to 100 μm. If the thickness is less than 10 μm, it is difficult to coat uniformly, and when a mechanical external force is applied, the steel pipe is likely to be exposed. Further, it is not economical when the thickness is more than 1000 μm, and the coating method is limited to the extrusion coating method.

The method of coating the steel pipe may be an extrusion coating method, a powder coating method, a heat shrinking method of the shape memory tube, a coating method after being made into a paint, and the coating method after being made into a paint is spray coating or spatula. Ordinary means such as application, brush coating, roller coating, and lacquer coating can be used. Further, the resin can be made into a paint by dispersing and dissolving it in water, an organic solvent or the like. Further, as the pretreatment of the steel pipe surface, one or more of blast treatment, pickling, degreasing, chemical conversion treatment (chromate treatment, etc.) can be performed.

A primer layer may be provided between the steel pipe and the resin coating layer to improve adhesion. This primer has good adhesiveness to both the surface of the steel pipe and the resin coating layer, and is a fluororesin such as tetrafluoroethylene resin, perfluoroalkoxy resin, fluorinated ethylene propylene resin, polyimide, polyether sulfide, polyphenylene sulfide, poly Those obtained by adding or copolymerizing ether ether ketone are preferable. A suitable mixing ratio of the fluororesin and the polyimide is about 0.1 to 2 and particularly about 0.2 to 1 with respect to 1 part by weight of fluorine. The thickness of the primer layer may be about 5 to 500 μm, preferably about 10 to 100 μm.

On the outer peripheral surface of the steel pipe, a metal coating may be used for improving the adhesion between the steel pipe and the resin coating layer and the primer and improving the corrosion resistance. This metal is not particularly limited, and a normal corrosion resistant metal may be used. The coating method is also not particularly limited, but a spraying method, a plating method and the like are preferable. Further, one or more of blasting treatment, pickling, degreasing, chemical conversion treatment and the like can be performed as the pretreatment of the metal coated surface.

[0015]

【Example】

Examples 1 to 46 A resin coating layer was formed on 25A SGP steel pipe by the method shown in Table 1,
The piping materials of Examples 1 to 46 were used.

Comparative Examples 1 and 2 A resin coating layer was formed on a 25A SGP steel pipe by the method shown in Table 1,
The pipe materials of Comparative Examples 1 and 2 were used.

Table 1 shows the presence / absence of abnormalities when the pipe materials of Examples 1 to 46 and Comparative Examples 1 and 2 were allowed to stand at 250 ° C. for 10 hours, and the flammability when they were lit by a burner for 10 seconds. .

As is apparent from the table, the piping materials of the examples show sufficient heat resistance and flame retardancy, and have good aesthetics such as ivory, red, beige, blue, yellow, white, clear, brown and silver. It was

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

As described above, according to the present invention, the pipe material is provided on the outer peripheral surface of the steel pipe with the resin coating layer having a film thickness of 10 to 1000 μm and made of a fluororesin having a calorific value of combustion of 3000 cal / g or less. It is possible to provide a piping material having good heat resistance, flame retardance, and good appearance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a piping material of the present invention.

FIG. 2 is a cross-sectional view of another example of the piping material of the present invention.

FIG. 3 is a cross-sectional view of an example of the piping material of the present invention.

FIG. 4 is a cross-sectional view of an example of the piping material of the present invention.

[Explanation of symbols]

 1 ... Steel pipe 2 ... Metal coating layer 3 ... Primer layer 4 ... Resin coating layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B05D 7/24 302 L 0823-4F B32B 1/08 7415-4F

Claims (3)

[Claims] 1. The calorific value of combustion is 3000 cal / g on the outer circumference of the steel pipe.
Piping material with the following fluorocarbon resin as a base material and a resin coating layer with a film thickness of 10 to 1000 μm provided 2. The pipe material according to claim 1, wherein a primer is interposed between the steel pipe and the resin coating layer. 3. The pipe material according to claim 1, wherein the steel pipe is metal-coated on the outer peripheral surface.