JP2001012689A - Pipe cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe cover free from the wrinkling of a coating material or swelling or denting of the surface which impairs the appearance quality, having a coating material never causing the corrosion of an aluminum foil laminated thereon for preventing moisture and water, with excellent dimensional stability. SOLUTION: This pipe cover is formed by adhering a coating material consisting of a neutral paper 4, an aluminum foil 5 laminated with a polyethylene film 5, and a polyester film laminated in order from the inside, to the surface of a heat insulating layer consisting of a synthetic resin foamed body, and adhering a lining material to the reverse side. In this case, the toughness per 25 mm-width measured by loop method of the coating material is 350-1000 g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe cover used as a heat insulating material for piping for transporting a low-temperature fluid or a high-temperature fluid.

[0002]

2. Description of the Related Art Insulation of pipes for transporting low-temperature fluids such as LNG and LPG or high-temperature fluids such as hot water, heated air and heated heavy oil is generally performed by heat insulating layer 1 made of a synthetic resin foam such as polyurethane as shown in FIG. This is performed by surrounding the pipe with a semi-cylindrical pipe cover composed of a coating material 2 bonded to the surface of the heat insulating layer and an inner surface material 3 bonded to the back surface. This pipe cover puts the coating material and inner surface material in the mold,
Made by placing a semi-cylindrical shape and spaced apart, injecting a liquid synthetic resin stock solution into the space formed between both materials, foaming and curing, and simultaneously integrating the three into a thick half-cylindrical shape Is done. Of course, in addition to the semi-cylindrical shape, a shape obtained by dividing a cylinder into three to five along the axis may be used.
The coating material is provided to prevent the heat insulating layer from absorbing moisture and deteriorating the performance. As shown in FIG. 3, the nonwoven fabric 8 for providing the coating material 2 with rigidity from the inside and an aluminum foil for moisture prevention are used. 6. Laminated polyester film 7 for protecting aluminum foil was used. The pipe cover using the coating material of this configuration causes wrinkles in the coating material due to molding shrinkage generated after the synthetic resin stock solution is foamed and hardened or heat shrinkage during cooling, or occurred at the interface between the heat insulating layer and the coating material during molding. The air voids tend to cause swelling or dents on the surface, thereby impairing the appearance quality, and have the disadvantage of causing dimensional changes over time. In pipe covers used for large-diameter pipes, dimensional changes over time have been a problem that cannot be ignored. In order to improve the above-mentioned difficulties, the applicant has strengthened the stiffness by replacing the non-woven fabric of the coating material with pulp reinforced by adding an inorganic filler such as calcium carbonate and aluminum hydroxide and glass fiber, as shown in FIG. Then, the coating material is coated with an inorganic filler glass fiber reinforced pulp sheet 9 from the inside,
A method was proposed in which an aluminum foil 6 laminated with a polyethene film 5 and a polyester film 7 were laminated. (Act 3-26394)

[0003]

The pipe cover in which the inorganic filler glass fiber reinforced pulp layer is disposed on the innermost layer of the coating material has reduced wrinkles, air blisters, and surface swelling or dents. In some cases, there was a sign that the inorganic filler incorporated in the pulp corroded the aluminum foil, and it was expected that the performance of the heat insulating layer might be reduced.

[0004] The present invention relates to a wrinkle of the coating material which impairs the appearance quality,
An object of the present invention is to provide a pipe cover that has a coating material that prevents the occurrence of swelling or dents on the surface and that does not cause corrosion on the laminated aluminum foil for moisture proof and waterproof, and has excellent dimensional stability over time. Things.

[0005]

Means for Solving the Problems After the wrinkles of the covering material are integrated with the foamed layer in the pipe cover manufacturing process, when the foamed layer is molded and contracted by cooling, the covering material follows the contraction of the foamed layer. It is tried to shrink, but it is difficult to expand and contract itself, so if the adhesive strength with the foam layer or the in-layer adhesive strength of the coating material is low, it is said that it was a result of shrinking due to local delamination and bending Conceivable. Therefore, the waist strength of the covering material is set to a size that does not deform against the shrinkage stress of the foam acting along the covering material, and the adhesive strength between the covering material and the foam and the in-layer adhesive strength of the covering material are increased. This will eliminate wrinkles. Enlarges the stiffness of the coating material, inflates the surface caused by the gas pressure of the air voids generated at the interface between the foam and the coating material being different from the atmospheric pressure. If the force required to cause the deformation is larger, the swelling or dent does not appear even if air voids are generated, and the problem in appearance quality can be solved. In addition, if the covering material becomes stiff, the deformation of the foam is restrained, and the dimensional change over time hardly occurs. If the fibrous or pulp layer provided in the innermost part of the covering material is made to be free from acidic or alkaline substances that react with aluminum to increase the stiffness of the covering material, the problem of aluminum foil corrosion can be solved. Solvable.

That is, according to the present invention, a heat insulating layer made of a synthetic resin foam, a coating material disposed on the surface of the heat insulating layer and an inner surface material disposed on the back surface are integrally formed, and the coating material is neutralized from the inside. , An aluminum foil laminated with a polyethylene film, and a polyester film in this order.

The neutral paper used for the innermost layer of the coating material is manufactured from bleached chemical pulp that does not contain a substance that reacts with aluminum. The coating material has a waist strength of 2 measured by a loop method.
It is set to be 350 to 1000 g per 5 mm. If the waist strength is less than 300 g, wrinkles occur, and it is not possible to prevent the occurrence of bulging or dents on the surface. If it exceeds 1000 g, it becomes difficult to bend, and it becomes difficult to form a small-diameter pipe.

[0008]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional view of a covering material of a pipe cover according to an embodiment of the present invention, and FIG. 2 is a perspective view of a general pipe cover. In the drawing, reference numeral 1 denotes a foam layer, 2 denotes a covering material, and 3 denotes an inner surface material. The covering material 2 that adheres to the surface of the foam layer 1 to protect the foam layer 1 is made of a neutral paper 4 from the side close to the foam layer, that is, an aluminum foil 6 laminated with a polyethylene film 5 on the inner side, and a polyester film 7. In this order.

As a synthetic resin foam for forming the foam layer 1, urethane foam is preferred because of its low thermal conductivity and good workability during production. As neutral paper, cup base paper used for food and drink containers such as milk packs and paper cups is suitable because it does not contain a substance that reacts with aluminum and can be obtained at low cost, and the basis weight is 300 to 800 g / m ^2. Is used. Polyethylene film is 25-1 thick
The thickness is 25 μm, the thickness of the aluminum foil is 7 to 100 μm, and the thickness of the polyester film is 15 to 30 μm. The material of the inner surface material 3 is not particularly limited as long as it has heat resistance, cold resistance and flexibility, and is made of asphalt felt, roofing, or the like.

[0010]

EXAMPLE A 30 .mu.m thick polyethylene film laminated with a 30 .mu.m thick polyethylene film and a 100 .mu.m thick polyester film were laminated on each of a cup base paper, a nonwoven fabric and a filler glass fiber reinforced pulp sheet adjusted to the basis numbers shown in Table 1. A coating material was prepared by lamination, and a pipe cover was trial-produced according to a conventional method using the above coating material and an inner surface material made of asphalt felt. Immediately after the appearance inspection of the prototype pipe cover according to the following criteria,
The test was performed 24 hours after standing in a -5 ° C constant temperature bath and 2 days after standing at room temperature. The results are shown in Table 1. Next, it was disassembled and the delamination strength of the innermost layer was measured. The results are shown in Table 1. Further, a test for the corrosiveness of the aluminum foil laminated on the coating material was performed by the following method. The results are shown in Table 1.

[0011]

[Table 1]

Method of measuring waist strength When a coating material is cut into strips and a cylindrical rod having an outer diameter of 5 mm is pressed against the side of a loop having a width of 25 mm and an inner diameter of 50 mm joined at both ends in the longitudinal direction, and the loop buckles. The load was defined as waist strength and was expressed in g / 25 mm.

Judgment Criteria for Appearance Inspection: Blisters or dents having a diameter of 20 mm or less with 5 or less occurrences are evaluated as ○;
Ten of them were indicated by Δ, and those other than the above were indicated by X.

Method for Corrosion Test of Aluminum Foil A strip cut into a strip was placed in a thermostat at a temperature of 70 ° C. and a relative humidity of 95%, left for 30 days, taken out, and peeled off at the polyethylene film position while hot. The foil was visually inspected for corrosivity. Inspection results were indicated by を when no signs of corrosion were observed, and by X when signs were observed.

In Prototype No. 3, although the cup base paper is used for the innermost layer, since the waist strength is less than 300 g / 25 mm, the appearance quality is slightly deteriorated after standing. Prototype No. 4 using a nonwoven fabric for the innermost layer has poor appearance quality. In prototype No. 5, corrosion was observed on the aluminum foil.

[0016]

According to the present invention, the covering material of the pipe cover is formed by laminating an aluminum foil and a polyester film in which polyethylene film is laminated on a neutral paper and the waist strength is set to 350 to 1000 g / 25 mm width. In addition, the wrinkles of the coating material which impairs the appearance quality, the swelling of the pipe cover surface, the occurrence of dents, etc. are prevented, and the aluminum foil is not corroded, so that the excellent performance of the pipe cover can be maintained for a long time. Have.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a covering material of a pipe cover according to an embodiment of the present invention.

FIG. 2 is a perspective view of a general pipe cover.

FIG. 3 is a partial cross-sectional view of a coating material of a conventional pipe cover.

FIG. 4 is a partial cross-sectional view of another conventional pipe cover covering material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat insulation layer 2 Coating material 3 Inner surface material 4 Neutral paper 5 Polyethylene film 6 Polyester film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B32B 27/32 B32B 27/32 Z 27/36 27/36 29/00 29/00

Claims (2)

[Claims] 1. A heat insulating layer made of a synthetic resin foam, a coating material disposed on a surface of the heat insulating layer, and an internal material disposed on a back surface of the heat insulating layer are integrally formed, and are disposed so as to surround a high-temperature or low-temperature fluid transport pipe. A pipe cover, characterized in that the covering material is formed by laminating neutral paper, an aluminum foil laminated with a polyethylene film, and a polyester film in this order from the inside. 2. The pipe cover according to claim 1, wherein a waist strength per 25 mm width of the coating material measured by a loop method is 350 to 1000 g.