JP2001012662A - Flexible pipe covered by resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the inspection of the existence/absence of the hole made by the strike in of a nail, without hurting a flexibility and durability by forming a resin layer by polyolefin system resin with the tensile elastic rate of a specific range. SOLUTION: A flexible pipe 3 covered by a resin is formed by covering a corrugated pipe 1 made of for example thin stainless steel by a resin layer 2. Here, the resin layer 2 is formed by polyolefin system resin whose tensile elastic rate is 590-1400 kg/cm2, for example ethylene-acrylic ester copolymer and made by mixing properly the additive such as an anti-weathering material, fire retardant agent, anti-oxidant and colorant. In the polyolefin system resin with the tensile elastic rate of this range, when a hole is made on a metal flexible pipe 1 by striking the nail in, while ensuring a flexibility sufficiently, the end of broken resin layer 2 hardly blocks the clearance between the resin layer 2 and nail. Therefore, it is easy inspect the existence/absence of the hole made by the strike in of the nail without hurting the flexibility and durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin-coated flexible tube in which a metal flexible tube is covered with a resin layer.

[0002]

2. Description of the Related Art The above-mentioned resin-coated flexible tube is used, for example, for gas pipes in buildings, and is made of a metal-made flexible tube which is thinned in order to ensure flexibility. The flexible tube is covered with a resin layer. If such a resin-coated flexible tube is used to pipe the inside of the interior material so as to hide it, a nail or the like may be accidentally driven into the piping from the outside of the interior material, and a thin metal pipe may be used. A hole may be formed in the flexible tube, and after performing interior work involving nailing,
For example, the presence or absence of perforation is inspected by examining the degree of pressure drop when pressure is applied to the piping. However, in the conventional resin-coated flexible tube, since the resin layer covering the metal flexible tube is formed of a resin having high resilience and adhesion, a hole is formed in the metal flexible tube. Also, the end of the torn resin layer is easily deformed so as to close the gap between the resin layer and the nail, etc., and the leakage of the fluid in the pipe to the outside of the resin layer is reduced. There is a problem that becomes difficult. For this reason, as described in, for example, Japanese Patent Application Laid-Open No. 9-314048, while securing the flexibility of the resin-coated flexible tube, a nail or the like is driven into the metal flexible tube to make a hole. When the metal layer is formed of a vinyl chloride resin having a Shore durometer hardness (D type) of 18 to 37, the metal layer is formed so that the end of the broken resin layer does not easily block the gap between the resin layer and the nail. A resin-coated flexible tube coated with a flexible tube has been proposed.

[0003]

However, in the resin-coated flexible tube proposed above, since the resin layer is formed of a vinyl chloride resin containing chlorine, there is a disadvantage that harmful gas containing dioxin and the like is generated during incineration. In addition, since hydrogen chloride generated from chlorine contained in the vinyl chloride resin easily corrodes the metal flexible tube, the durability may be impaired. The present invention has been made in view of the above circumstances, and makes it easy to inspect the presence or absence of a hole that has been driven into a nail without impairing flexibility and durability. It is an object of the present invention to be able to prevent the occurrence of the problem.

[0004]

According to a first aspect of the present invention, there is provided a resin-coated flexible tube in which a metal flexible tube is covered with a resin layer, wherein the resin layer has a tensile modulus of elasticity. (kg
/ Cm ² ) of 590 to 1500. That is, since the polyolefin-based resin forming the resin layer does not contain a halogen group element such as chlorine, there is little possibility that corrosive gas such as hydrogen chloride is generated, and there is a possibility that harmful gas containing dioxin or the like is generated at the time of incineration. Also less. Further, when the tensile elastic modulus (kg / cm ² ) of the polyolefin resin forming the resin layer is less than 590, when the hole is made in the metal flexible tube by driving a nail or the like, the broken resin is used. The edge of the layer is easy to close the gap between the resin layer and the nail, etc.
When (kg / cm ² ) exceeds 1500, sufficient flexibility cannot be ensured, and the tensile modulus (kg / cm ² ) is 590 to 590.
In the range of 1500, when a nail or the like is punched into a metal flexible tube while securing sufficient flexibility, the end portion of the torn resin layer is formed between the resin layer and the nail or the like. It becomes difficult to close the gap. Therefore, it is easy to inspect the presence or absence of a hole that has been driven into by nails or the like without impairing flexibility and durability, and it is possible to prevent generation of harmful gas during incineration.

A feature of the invention according to claim 2 is that the polyolefin resin is an ethylene-ethyl acrylate copolymer having a tensile modulus (kg / cm ² ) of 590 to 1400. That is, the tensile modulus (kg / c
m ² ) is a resin-coated flexible tube obtained by coating a metal flexible tube with a resin layer formed of an ethylene-ethyl acrylate copolymer having a 590 to 1400, without impairing the flexibility and durability of the resin-coated flexible tube. Is easier to inspect for the presence of a hole
Moreover, the generation of harmful gases during incineration can be prevented. Moreover, ethylene-ethyl acrylate copolymer is flame-retardant,
It is preferable because it is excellent in strength, low-temperature brittleness, and oil resistance.

A feature of the invention according to claim 3 is that the polyolefin resin is an ethylene-vinyl acetate copolymer having a tensile modulus (kg / cm ² ) of 700 to 1500. That is, the tensile modulus (kg / cm ² ) is 7
A resin-coated flexible tube in which a metal flexible tube is coated with a resin layer formed of a copolymer of ethylene and vinyl acetate of No. 00 to 1500, without being impaired in flexibility or durability, is exposed to nails or the like without being damaged. It is easy to inspect the presence or absence of the hole, and furthermore, generation of harmful gas at the time of incineration can be prevented. In addition, ethylene-
Vinyl acetate copolymers are preferred because they are also excellent in flame retardancy, strength, and low-temperature brittleness.

According to a fourth aspect of the present invention, the polyolefin resin is composed of an ethylene-ethyl acrylate copolymer having a tensile modulus (kg / cm ² ) of 590 to 1400, and a tensile modulus (kg / cm ² ). cm ² ) is 700 to 1500
And ethylene-vinyl acetate copolymer. That is, tensile modulus (kg / cm ² )
And an ethylene-ethyl acrylate copolymer having a tensile modulus (kg / cm ² ) of 700 to 150
Forming a resin layer with a polyolefin resin blended with an ethylene-vinyl acetate copolymer of No. 0, it is easy to inspect the presence or absence of a hole that has been driven into a nail without impairing flexibility and durability. In addition, a resin-coated flexible tube capable of preventing generation of harmful gas at the time of incineration can be manufactured. In addition, it is easy to adjust the degree of flame retardancy, strength, low temperature brittleness, and oil resistance.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 shows a fuel gas pipe such as a city gas or a propane gas in which a thin stainless steel (SUS304) corrugated pipe 1 as an example of a metal flexible pipe is covered with a resin layer 2. 1 shows a resin-coated flexible tube 3 used for the present invention. The resin layer 2 has a tensile modulus of elasticity (kg / cm ² ) of 590 to 590.
It is formed of an ethylene-ethyl acrylate copolymer as a polyolefin resin of No. 1400, and additives such as a weathering agent, a flame retardant, an antioxidant, a coloring agent, and an antioxidant are appropriately compounded.

[Second Embodiment] Instead of the resin layer 2 formed of the ethylene-ethyl acrylate copolymer shown in the first embodiment, a tensile elastic modulus (kg / cm ² ) of 700 to 700 is used.
The corrugated tube 1 may be covered with a resin layer 2 formed of an ethylene-vinyl acetate copolymer which is a polyolefin resin of 1500 to form a resin-coated flexible tube 3. Other configurations are the same as those of the first embodiment.

[Third Embodiment] Instead of the resin layer 2 formed of the ethylene-ethyl acrylate copolymer shown in the first embodiment, a tensile elastic modulus (kg / cm ² ) of 590 to 590 is used.
A corrugated tube 1 comprising a resin layer 2 formed of a polyolefin resin blended with an ethylene-ethyl acrylate copolymer of 1400 and an ethylene-vinyl acetate copolymer having a tensile modulus (kg / cm ² ) of 700 to 1500 To form the resin-coated flexible tube 3. Other configurations are the same as those of the first embodiment.

[Other Embodiments] The resin-coated flexible tube according to the present invention may be used for water supply or hot water supply piping, cooling / heating heating medium piping, cold / hot water piping, steam piping, or the like. 2. The resin-coated flexible tube according to the present invention may be a flexible tube made of a soft metal such as a copper tube or an aluminum tube covered with a resin layer. 3. The resin-coated flexible tube according to the present invention may be a flexible tube made of a soft metal such as a copper tube or an aluminum tube that has not been subjected to corrugation or bellows processing, covered with a resin layer.

[0012]

[First Embodiment] Thin stainless steel (SUS3)
04) Using the corrugated tube 1 made of resin, the tensile elastic modulus (kg / c) as the resin-coated flexible tube shown in the first embodiment
m ² ) is a resin layer 2 formed of each of ethylene-ethyl acrylate copolymer (EEA) of 594, 1028 and 1387
And a resin-coated flexible tube 3 having a nominal diameter of 20 A (hereinafter, referred to as Examples 1, 2, and 3) and a tensile modulus of elasticity (kg / cm ² ).
Is a resin-coated flexible tube 3 having a nominal diameter of 20A for comparison and coated with a resin layer 2 formed of each of ethylene-ethyl acrylate copolymers (EEA) of 582 and 1436 (hereinafter referred to as Comparative Examples 1 and 2). ) And a conventional resin-coated flexible tube 3 (hereinafter, referred to as a conventional example) having a nominal diameter of 20A and covered with a resin layer 2 formed of a vinyl chloride resin (PVC). Pipe) standard specifications (1998
(Published by the Japan Gas Association). [Table 1] shows the comparison results of those performance tests.

[0013]

[Table 1]

The contents of each performance test in Table 1 will be described below. The nailing test was performed in Examples 1, 2 and 3 and Comparative Examples 1 and 2.
2 and the conventional example, whether or not the end of the resin layer 2 is likely to close the gap between the resin layer 2 and the nail 4 when the nail 4 is driven into the resin-coated flexible tube 3. As shown in FIG. 2, both ends of the resin-coated flexible tube 3 are air-tightly closed with caps 6 and 7, and pressurized air of 3 kPa is applied to the inside of the corrugated tube 1 and the buffer tank T by 10 kPa. The amount of pressure drop for one minute inside the corrugated tube 1 when the resin-filled flexible tube 3 was filled until the nail 4 penetrated was measured by a pressure gauge 8 connected to the cap 7. In [Table 1], the pressure drop amount was set to 0.
In the case of 15 kPa or more, it is indicated by ◎, and in some of the 10 lines, it is indicated by ○, in the case of 0.15 kPa or more, and in the case of less than 0.15 kPa, the cross is indicated by x.

Each of a torsion test, a weather resistance test, a flame retardancy test, a thermal cycle test, a coating adhesion test, a flexibility test, a bending test, and a solution resistance test is performed using a stainless steel flexible pipe for gas (flexible pipe). ) Standard specifications (July 1998
Each test was conducted for each of Examples 1, 2 and 3, Comparative Examples 1 and 2, and a conventional example, and all three met the standard specifications. Indicates that some of the three do not meet the standard specifications, and indicates that all three do not meet the standard specifications.

According to Table 1, the tensile modulus of the ethylene-ethyl acrylate copolymer (EEA) forming the resin layer 2 is shown.
When (kg / cm ² ) is less than 590, when the nail 4 is driven into the corrugated tube 1 to form the hole 5, the end of the torn resin layer 2 is formed between the resin layer 2 and the nail 4. If the gap is easily closed and the tensile elastic modulus (kg / cm ² ) exceeds 1400, sufficient flexibility cannot be secured, and the tensile elastic modulus (kg / cm ² )
/ Cm ² ) is in the range of 590 to 1400, the nail 4 is driven into the corrugated tube 1 with a hole 5 while securing sufficient flexibility.
It can be seen that the end of the torn resin layer 2 is unlikely to close the gap between the resin layer 2 and the nail 4 when dawn.

Second Embodiment Thin stainless steel (SUS)
304), the tensile elastic modulus (kg / c) of the resin-coated flexible tube shown in the second embodiment using the corrugated tube 1 made of
m ² ) is a resin-coated flexible tube 3 having a nominal diameter of 20 A coated with a resin layer 2 formed of each of ethylene-vinyl acetate copolymers (EVA) of 729, 1152 and 1473 (hereinafter referred to as Examples 4 and 5). , 6) and a tensile modulus of elasticity (kg / cm ² ) of 6
74, 1536 ethylene-vinyl acetate copolymers (E
VA), a resin-coated flexible tube 3 having a nominal diameter of 20 A (hereinafter referred to as Comparative Examples 3 and 4) coated with a resin layer 2 formed of VA, and a resin formed of a vinyl chloride resin (PVC). Conventional resin-coated flexible tube 3 having a nominal diameter of 20 A coated with a layer 2
(Hereinafter referred to as a conventional example) were manufactured with dimensions specified in a stainless steel flexible pipe (flexible pipe) standard specification for gas (issued by the Japan Gas Association in July 1998).
[Table 2] shows the comparison results of those performance tests.

[0018]

[Table 2]

The contents of each performance test in [Table 2] are the same as those shown in the first embodiment, and the description thereof will be omitted. From Table 2, the tensile modulus (kg / cm ² ) of the ethylene-vinyl acetate copolymer (EVA) forming the resin layer 2 is shown.
Is less than 700, when the nail 4 is driven into the hole 5 in the corrugated pipe 1, the end of the torn resin layer 2 is likely to close the gap between the resin layer 2 and the nail 4, and the tension is pulled. When the elastic modulus (kg / cm ² ) exceeds 1500, sufficient flexibility cannot be secured, and the tensile elastic modulus (kg / cm ² ) is 70.
In the range of 0 to 1500, while ensuring sufficient flexibility,
When the nail 4 is driven into the hole 5 in the corrugated pipe 1, the end of the torn resin layer 2 is separated from the resin layer 2 by the nail 4.
It can be seen that it is difficult to close the gap with.

[Brief description of the drawings]

FIG. 1 is a sectional view of a resin-coated flexible tube.

FIG. 2 is a side view showing a test method of a nailing test.

[Explanation of symbols]

 1 Flexible metal tube 2 Resin layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H111 AA03 BA01 BA15 BA34 CA44 CA52 CB03 DA26 DB11 DB18 4F100 AB01A AB04 AK03B AK68B AK70B AL05B BA02 DA11A DA13 GB90 JK07B JK14 JK17A YY00B

Claims (4)

[Claims] 1. A resin-coated flexible tube in which a metal flexible tube is covered with a resin layer, wherein the resin layer has a tensile modulus of elasticity (kg / cm ² ) of 590 to 590.
A resin-coated flexible tube made of 1500 polyolefin resin. 2. The resin-coated flexible tube according to claim 1, wherein the polyolefin resin is an ethylene-ethyl acrylate copolymer having a tensile modulus (kg / cm ² ) of 590 to 1400. 3. The resin-coated flexible tube according to claim 1, wherein the polyolefin-based resin is an ethylene-vinyl acetate copolymer having a tensile modulus (kg / cm ² ) of 700 to 1500. 4. An ethylene-ethyl acrylate copolymer having a tensile modulus (kg / cm ² ) of 590 to 1400 and a tensile modulus (kg / c)
m ²⁾ ethylene is 700 to 1500 - a resin-coated flexible tube according to claim 1, wherein is obtained by blending a vinyl acetate copolymer.