JP2018185017A - Flexible hose for gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible hose for gas capable of preparing a specific uneven shape of a hose inner surface to reduce pressure loss of fluid to thereby reduce flow rate reduction of fluid, and having oil resistance performance and gas barrier performance in order to mainly convey gas.SOLUTION: A flexible hose for gas comprises, in an order from a hose inner peripheral surface, a first resin layer (A1), a second resin layer (A2), an outer surface layer (B) and a reinforced hard core material (C), and satisfies the following conditions (1), (2): (1) when the hose is extended in a lengthwise direction, 5 mm≤X≤25 mm, where X (mm) represents repetition unit of an apex of a convex part on the inner peripheral surface; (2) 0.003≤Z/ID≤0.05, where Z (mm) represents a depth of a recess between convex parts on the hose inner peripheral surface, and ID (mm) represents a hose inner diameter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flexible gas hose having a specific uneven shape on the inner surface. Since the gas flexible hose of the present invention has a small fluid pressure loss, it has a feature that the flow rate of fluid is small. That is, when the gas flexible hose of the present invention is used by being connected to, for example, a pump or a blower, energy and costs such as increasing the source pressure or increasing the capacity of the pump itself are wasted. There is an advantage that there is no need to hang.

In particular, the required performance of the gas hose is required to have oil resistance and gas impermeability (gas barrier properties). Techniques for achieving these performances have been studied in the past.For example, a polyolefin resin material having oil resistance is used on the inner peripheral surface in contact with the fluid, and a resin composition having gas barrier properties is further formed thereon. Laminating hoses and tubes are common.
In addition, with the downsizing and energy saving of equipment such as a pump for sucking and feeding gas, there is a strong demand for low pressure loss of the hose with respect to gas.
Patent Documents 1 to 4 are examples of techniques related to a hose and a tube having oil resistance and gas barrier properties.
Patent Document 1 discloses a technique for manufacturing a laminated hose comprising three layers using an ethylene-vinyl alcohol copolymer as an outermost layer of a hose, a polyolefin resin as an innermost layer, and a modified polyolefin resin as an adhesive layer. However, the hose of Patent Document 1 is intended to improve the adhesiveness of each resin layer constituting the gas hose, and has a gas barrier property due to the ethylene-vinyl alcohol copolymer layer and an uneven shape on the inner peripheral surface of the hose. It is not intended to reduce the pressure loss by applying.
Patent Documents 2 to 4 are all related to a laminated tube excellent in gas barrier properties, in which a gas barrier layer made of an ethylene-vinyl alcohol copolymer or the like is provided in at least one layer of the laminated tube. When the hose is connected to a pump or the like, it is not satisfactory from the viewpoint of fluid pressure loss.
Further, Patent Document 5 mainly relates to a duct hose for air conditioning, and it is considered that the presence of an uneven state in the pipe is an undesirable element from the viewpoint of pressure loss, and there is almost no uneven state in the pipe. No flexible tubing technology is disclosed.
However, even if the duct hose technology for air conditioning where the inside of the pipe is almost flat and there is almost no unevenness in the pipe is applied to the gas hose, the gas barrier property, which is the required performance of the gas hose, is satisfied. In addition, when the hose is connected to a pump or the like and used, it is not satisfactory in terms of fluid pressure loss, and there is room for improvement.

Japanese Patent No. 5044744 Japanese Patent No. 5360803 Japanese Patent No. 4634325 Japanese Patent No. 2824111 JP 2014-129838 PR

  An object of the present invention is to provide a flexible gas hose that effectively reduces the pressure loss of a fluid without losing the excellent characteristics inherent in the gas hose, in particular, oil resistance and gas barrier properties. That is.

  As a result of intensive studies to achieve the above object, the present inventors, in order, from the inner peripheral surface of the hose, first resin layer (A1) / second resin layer (A2) / outer surface layer (B) / reinforced hard core material. It was found that a gas flexible hose comprising (C) and satisfying a specific structure can reduce the pressure loss of the fluid, and the present invention was completed.

That is, the present invention comprises, in order from the inner peripheral surface of the hose, the first resin layer (A1) / second resin layer (A2) / outer surface layer (B) / reinforced hard core material (C), and the following (1), A flexible gas hose that satisfies all the conditions of (2).
(1) When deployed in the length direction of the hose, when X (mm) is the repeating unit of the convex portion apex on the inner peripheral surface, 5 mm ≦ X ≦ 25 mm,
(2) When the depth of the recess between the convex portions on the inner peripheral surface of the hose is Z (mm) and the inner diameter of the hose is ID (mm), 0.003 ≦ Z / ID ≦ 0.05.

In the present invention, the first resin layer (A1) or the second resin layer (A2) is preferably made of any one of the following resin compositions 1) to 3). A flexible hose.
1) The first resin layer (A1) is composed of a single layer of thermoplastic polyurethane, and the second resin layer (A2) is composed of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol%. 2) The first resin layer (A1) is a single layer made of a resin composition in which an ethylene-vinyl alcohol copolymer and a thermoplastic polyurethane are mixed. 3) The first resin layer (A1) is a polyolefin in order from the inner peripheral surface. An ethylene-vinyl alcohol copolymer comprising a two-layer laminate co-extruded so as to be a resin / modified polyolefin resin, wherein the second resin layer (A2) has an ethylene content of 20 to 60 mol%. There is.

  Furthermore, this invention contains said flexible gas hose which a reinforced hard core material (C) consists of hard vinyl chloride resin or hard polyolefin resin as a preferable form.

  More preferably, when the length between the reinforced hard core materials (C) is Y (mm), the relationship between the above-described convex vertex of the inner peripheral surface and the repeating unit X (mm) is 0.90 ≦ X / Y It is the flexible hose for gas as described in the above satisfying ≦ 1.10.

  Since the gas flexible hose of the present invention has a specific uneven shape on the inner peripheral surface of the hose, the pressure loss of the fluid is reduced and the decrease in the flow rate of the fluid can be reduced. Therefore, it is possible to eliminate the need to waste energy and costs such as increasing the source pressure of the pump and increasing the capacity of the pump itself. At the same time, it is possible to achieve both oil resistance and gas barrier properties that are common in conventional gas hoses.

  FIG. 1 shows an overall view and a partial cross-sectional schematic view of a gas flexible hose representing an embodiment of the present invention. As shown in FIG. 1 (enlarged sectional view 2), the flexible hose for gas of the present invention has a first resin layer (A1) / second resin layer (A2) / outer surface layer (B) / It is a laminated molded body made of a reinforced hard core material (C). The uneven | corrugated shape of a 1st resin layer (A1)-reinforcement hard core material (C) and a hose inner peripheral surface is demonstrated in detail below.

[Uneven shape of hose inner surface]
The gas flexible hose of the present invention satisfies the following conditions (1) and (2) when deployed in the length direction.
(1) When deployed in the length direction of the hose, the repeating unit of the convex vertex of the inner peripheral surface is X (mm), and 5 mm ≦ X ≦ 25 mm.
(2) When the depth of the recess between the convex portions on the inner peripheral surface of the hose is Z (mm) and the inner diameter of the hose is ID (mm), 0.003 ≦ Z / ID ≦ 0.05.

It is important that the repeating units X (mm) of the convex vertices on the inner peripheral surface are configured at equal intervals of 5 mm ≦ X ≦ 25 mm. And the repeating unit X (mm) of the convex part vertex of an internal peripheral surface can take an appropriate value in the above-mentioned range according to the magnitude | size of hose internal diameter ID (mm). For example, when the hose inner diameter ID (mm) is 25 mm, the repeat unit X (mm) is preferably in the range of 5 to 8 mm, and when 50 h, the repeat unit X (mm) is preferably in the range of 9 to 12 mm, and 75 mm. Then, the repeating unit X (mm) is preferably in the range of 11 to 14 mm, the repeating unit X (mm) is preferably 14 to 18 mm if it is 100 mm, and the repeating unit X (mm) is 22 to 25 mm if it is 200 mm. Is preferred.
Moreover, when the repeating unit X (mm) of the convex vertex of the inner peripheral surface is less than 5 mm or exceeds 25 mm, the pressure loss of the fluid increases.

  The repeating unit X (mm) of the convex portion apex on the inner peripheral surface is obtained by observing the cross-sectional shape of the hose developed in the length direction with a microscope or a magnifier with a scale of 8 times or more, and between the convex apexes. It can be determined by measuring the distance.

Next, the depth Z (mm) of the recess between the convex portions on the inner peripheral surface of the hose is in the range of 0.003 ≦ Z / ID ≦ 0.05 when the inner diameter of the hose is ID (mm).
In the gas flexible hose in which the depth Z (mm) of the recess between the convex portions on the inner peripheral surface of the hose is in this range, the pressure loss of the fluid becomes small.
However, when the relation Z / ID between the depth Z (mm) of the dent and the hose inner diameter ID (mm) is less than 0.003, the inner peripheral surface is almost flat even if the inside of the tube is touched and observed. It can be seen that there is almost no uneven state, and the pressure loss of the fluid increases, and the resistance when flowing the fluid increases. In addition, when the relationship between the depth Z (mm) of the dent and the hose inner diameter ID (mm) is greater than 0.05, the pressure loss of the fluid increases, and the resistance when flowing the fluid increases. Not.
The relationship Z / ID between the recess depth Z (mm) and the hose inner diameter ID (mm) is preferably in the range of 0.003 to 0.03, and more preferably in the range of 0.005 to 0.03. Is more preferred.

The depth Z (mm) of the recess between the convex portions on the inner peripheral surface of the hose is observed with a microscope having a magnification of 10 times and the cross-sectional shape of the hose deployed in the length direction. It can be determined by measuring the distance between the connected line and the line connecting the deepest points of two or more recesses.
In addition, the inner diameter ID (mm) of the hose is a value obtained by inserting a taper gauge having a minimum graduation of 0.1 mm into the hose (the distance between the convex portions facing each other on the inner surface of the hose), and the depth Z ( mm) and adding a value twice as large.

[First resin layer (A1)]
The first resin layer (A1) of the present invention is excellent in oil resistance from the point of contact with a fluid. 1) The first resin layer (A1) is composed of a single layer of thermoplastic polyurethane, and the second resin layer (A2). Made of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol%, and 2) a resin composition in which the first resin layer (A1) is a mixture of an ethylene-vinyl alcohol copolymer and a thermoplastic polyurethane. 3) The first resin layer (A1) is a two-layer laminate co-extruded so that the first resin layer (A1) becomes a polyolefin resin / modified polyolefin resin in order from the inner peripheral surface. The resin layer (A2) is preferably any one of a laminate composed of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol%. Among these, 1) the first The resin layer (A1) is composed of a single layer of thermoplastic polyurethane, and the second resin layer (A2) is composed of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol%. It is more preferable from the viewpoint of simplification of manufacturing equipment and durability of the hose molded body. When the first resin layer (A1) is composed of 1) a single layer of thermoplastic polyurethane and 3) a two-layer laminate co-extruded so as to be a polyolefin resin / modified polyolefin resin in order from the inner peripheral surface Since the first resin layer (A1) alone cannot satisfy the gas barrier property as a hose structure, the second resin layer (A2) described later has an ethylene content of 20 to 60 mol% with an ethylene-vinyl alcohol copolymer. A gas barrier property is secured as a hose structure using a polymer.

  The thermoplastic polyurethane used in the present invention is meltable and usually comprises components such as a high molecular diol and an organic diisocyanate, and / or a low molecular diol. The polymer diol is a diol of a polymer compound obtained by polycondensation, addition polymerization (for example, ring-opening polymerization) or polyaddition, and representative examples thereof include polyester diol, polyether diol, polycarbonate diol, or these diols. Examples thereof include cocondensates (for example, polyester ether diol). These may be used singly or in combination of two or more.

  Polyester diols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methylpropane Diols of alkanes having 2 to 10 carbon atoms such as diols or mixtures thereof and aliphatic or aromatic having 4 to 12 carbon atoms such as glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, terephthalic acid and isophthalic acid Saturated polyester diols obtained from dicarboxylic acids or mixtures thereof, or polylactone diols such as polycaprolactone glycol, polypropiolactone glycol, and polyvalerolactone glycol are preferably used.

  Polyether diols such as polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol and polyhexamethylene ether glycol are preferably used as the polyether diol.

  Further, as the polycarbonate diol, an aliphatic having 2 to 12 carbon atoms such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol and the like. Alternatively, a polycarbonate diol obtained by polycondensation by causing diphenyl carbonate or phosgene to act on an alicyclic diol or a mixture thereof is preferably used. These polymer diols have an average molecular weight of 500 to 3,000, preferably 500 to 2,500. If the average molecular weight is too low, the compatibility with the organic diisocyanate is too good and the elasticity of the resulting polyurethane is poor.On the other hand, if the average molecular weight is too high, the compatibility with the organic diisocyanate will deteriorate and mixing during the polymerization process will occur. A stable polyurethane cannot be obtained due to the formation of a lump of gel.

The low-molecular diol as the second raw material is a low-molecular diol having a molecular weight of less than 500, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentane glycol, 3-methylpentane glycol, 1, Examples include aliphatic, alicyclic or aromatic diols such as 6-hexanediol and 1,4-pishydroxyethylbenzene. These may be used alone or in combination of two or more.

  Examples of the organic diisocyanate used in the present invention include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, 2,2′-dimethyl-4,4′-diphenylmethane diisocyanate, 1,3- or 1,4-bis (isocyanate). Aromatic, alicyclic or aliphatic diisocyanates such as methyl) benzene, 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate. These organic diisocyanates may be used alone or in combination of two or more.

  When manufacturing a thermoplastic polyurethane, you may use the suitable catalyst which accelerates | stimulates reaction of organic diisocyanate and diol as needed.

  It is optional to add various additives such as a colorant, a filler, an antioxidant, and an ultraviolet absorber to the thermoplastic polyurethane as long as the effects of the present invention are not impaired.

  The first resin layer (A1) may be a single layer composed of a resin composition in which an ethylene-vinyl alcohol copolymer and a thermoplastic polyurethane are mixed from the viewpoint of further improving gas barrier properties.

  In the present invention, the weight ratio of the ethylene-vinyl alcohol copolymer and the thermoplastic polyurethane is preferably 95/5 to 30/70. If the weight ratio of the ethylene-vinyl alcohol copolymer exceeds 95%, it is not preferable because the attachment of the metal fitting due to the eccentricity of the hose and the possibility of cracks and pinholes due to external stress increase. On the other hand, if it is less than 30%, the gas barrier property is insufficient. It is preferably 85/15 to 40/60.

  The method of mixing (blending) the ethylene-vinyl alcohol copolymer and the thermoplastic polyurethane is not particularly limited, and a dry blended resin is directly used, or more preferably, the dry blended resin is banbury. A pellet, which is put into a mixer, a single screw extruder or a twin screw extruder and pelletized is used. During pelletization or extrusion, it is desirable to keep the extrusion temperature as low as possible and to seal the hopper port with N2 in order to minimize product coloring, gel pinholes, and cracks. Further, at the time of pelletization or extrusion molding, it is optional to add a plasticizer, a heat stabilizer, a colorant, a filler and the like to the dry blend resin within a range that does not interfere with the present invention.

  The ethylene-vinyl alcohol copolymer of the present invention is a saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol%. If the ethylene content is less than 20 mol%, the melt moldability is poor, whereas if it exceeds 60 mol%, the gas barrier properties are insufficient. Moreover, it is preferable that the saponification degree of a vinyl acetate component is 90 mol% or more, and if it is less than that, gas barrier property is insufficient. On the other hand, if the degree of saponification is less than 90 mol%, the gas barrier property and the thermal stability are deteriorated. In addition, the ethylene-vinyl alcohol copolymer is copolymerized with butylene, propylene, a vinylsilane compound, and a vinylpyrrolidone compound within a range that does not interfere with the effects of the present invention, and includes a plasticizer, thermal stability, and ultraviolet light. It is optional to blend an absorbent, an antioxidant, a colorant, a filler and the like.

  The first resin layer (A1) includes 3) a laminate composed of two layers co-extruded so as to be a polyolefin resin / modified polyolefin resin in order from the inner peripheral surface. This is because the fluid in the hose is more effective in terms of chemical resistance than the conditions 1) and 2) described above when the oil in the hose has polarity such as vegetable oil, alcohol, or weak acidity. preferable. It describes about the polyolefin resin and modified polyolefin resin which comprise them.

  Examples of the polyolefin resin used for the first resin layer (A1) include polyethylene resins such as high density polyethylene (HDPE), medium density polyethylene, and low density polyethylene (LDPE), homopolypropylene, random polypropylene, and block polypropylene. Polypropylene resin and the like can be mentioned, but high-density polyethylene is preferable from the viewpoint of heat fusion with the second resin layer (A2) described later, extrusion processability, general versatility, and particularly ease of bending as a hose structure. It is.

  Examples of the olefinic monomer constituting the modified olefinic resin include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and 1-octadecene. Α-olefins such as These α-olefins can be used alone or in combination of two or more. Among these α-olefins, C2-6 olefins (particularly C2-4α-olefins) such as ethylene, propylene, and 1-butene are preferable.

  The modified olefin resin is usually an acid or epoxy modified olefin resin, and may be a modified product in which an acid or an epoxy group is introduced by, for example, copolymerization, terminal or side chain modification. Furthermore, the modified olefin resin may be a copolymer with a vinyl ester monomer or a saponified product thereof.

  In the case of an acid-modified product, the copolymerizable monomer serving as a modifier is a monomer having a carboxyl group (for example, an aliphatic monocarboxylic acid such as (meth) acrylic acid or crotonic acid, maleic acid, Fumaric acid, citraconic acid, aliphatic dicarboxylic acid such as itaconic acid), monomer having an acid anhydride group (eg, maleic anhydride, itaconic anhydride, aliphatic dicarboxylic anhydride such as citraconic anhydride, anhydrous Aromatic dicarboxylic acid anhydrides such as phthalic acid) and the like. These monomers may be alkyl esters (C1-4 alkyl esters such as methyl and ethyl).

  In the case of an epoxy-modified product, examples of the copolymerizable monomer that serves as a modifying agent include monomers having a glycidyl group (such as glycidyl (meth) acrylic acid, glycidyl (meth) acrylate, and allyl glycidyl ether). Is mentioned.

  In the case of a copolymer with a vinyl ester monomer, examples of the copolymerizable monomer include vinyl aliphatic carboxylates such as vinyl acetate and vinyl propionate.

  These copolymerizable monomers (modifiers) can be used alone or in combination of two or more. Of these copolymerizable monomers, (anhydro) unsaturated carboxylic acids such as (meth) acrylic acid, (anhydrous) maleic acid, fumaric acid, and (anhydrous) itaconic acid are preferred. In the present invention, in particular, the olefin resin may be modified with such an unsaturated carboxylic acid or a derivative thereof by graft copolymerization or the like.

  The proportion of the modifier (copolymerizable monomer) can be selected from the range of 50% by weight or less in the resin, and is, for example, 0.1 to 40% by weight, preferably 0.5 to 30% by weight, and more preferably 1 -25% by weight (particularly about 3-20% by weight).

Among the modified olefin resins, specific examples of the acid-modified olefin resin include, for example, a copolymer of ethylene and an unsaturated carboxylic acid or an ester thereof [for example, ethylene-maleic anhydride copolymer, ethylene- (meta ) Acrylic acid-maleic anhydride copolymer], polyolefins modified with (anhydrous) unsaturated carboxylic acid [for example, maleic anhydride grafted polypropylene], ionomers and the like. Specific examples of the epoxy-modified olefin resin include, for example, an ethylene-glycidyl methacrylate copolymer and an ethylene-glycidyl methacrylate-styrene copolymer. Examples of the copolymer with the vinyl ester monomer include saponified ethylene-vinyl acetate copolymers and ethylene-vinyl acetate copolymers having an ethylene content of 50 mol% or more. These modified olefin resins can be used alone or in combination of two or more. Of these modified olefin resins, unsaturated carboxylic acid modified olefin resins (for example, polypropylene graft-modified with maleic anhydride) are preferred.

When the polyolefin resin and the modified polyolefin resin are coextruded into a tape shape to form a flexible hose, the same method as the method for manufacturing the flexible hose described in Patent Document 1 is used. Alternatively, the first resin can be obtained by co-extrusion molding into a tape shape with the polyolefin resin and the modified polyolefin resin superimposed on the upper and lower layers, and winding the co-extrusion product on a hose molding machine to be described later. The layer (A1) can be formed. Although a shaping | molding method is not limited to these, From the point that the structure of the metal mold | die at the time of coextrusion molding is simple, the method mentioned later is more preferable.

[Second Resin Layer (A2)] The second resin layer (A2) of the present invention has a similar polarity because it is excellent in heat fusion with the first resin layer (A1) and the outer surface layer (B). In order to excel in gas barrier properties, it is preferable that the modified polyolefin resin described in the item of the first resin layer (A1) or an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol% is used. . This is because the hose has a laminated structure, so that the adhesive strength of each resin layer is further strengthened. If the adhesion is weak, a peeling phenomenon occurs between the resin layers, which is not suitable because it may block the flow path. In the case where the first resin layer (A1) is a single resin composition having excellent gas barrier properties, such as in the condition 2) described above, and is excellent in heat-fusibility with the outer surface layer (B). The second resin layer (A2) is not necessarily provided.

  The thickness ratio of each of the first resin layer (A1) and the second resin layer (A2) is preferably in the range of (A1) :( A2) = 0.5: 9.5 to 10: 0. When the thickness of the (A1) layer is less than the above range, the durability of the hose tends to be impaired.

[Outer surface layer (B)]
The thermoplastic resin constituting the outer surface layer (B) of the present invention is the first from the viewpoint of excellent adhesiveness or heat-fusibility with the first resin layer (A1) or the second resin layer (A2). A thermoplastic resin such as a soft polyvinyl chloride resin having a polarity similar to that of the resin layer (A1) or the second resin layer (A2), the thermoplastic polyurethane, the modified polyolefin resin, and the olefin thermoplastic resin described above. Elastomers, styrene thermoplastic elastomers and the like are preferable, and among them, soft polyvinyl chloride resins, thermoplastic polyurethanes, and modified polyolefin resins are more preferable. Examples of olefinic thermoplastic elastomers include general olefinic thermoplastic elastomers in which ethylene-propylene rubber (EPDM, EPM, etc.) is finely dispersed in an olefinic resin matrix, and styrene thermoplastic elastomers. As the styrene-butadiene block copolymer, styrene-isoprene block copolymer, or hydrogenated products thereof are preferable, but not limited thereto. For example, when the first resin layer (A1) is composed of a single layer of thermoplastic polyurethane and the second resin layer (A2) is composed of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol%, the outer surface The layer (B) is preferably a thermoplastic polyurethane excellent in heat-fusibility with the second resin layer (A2), and the first resin layer (A1) is composed of an ethylene-vinyl alcohol copolymer and a thermoplastic polyurethane. In the case of a mixed resin composition, the outer surface layer (B) is preferably soft polyvinyl chloride. 3) The first resin layer (A1) is polyolefin resin / modified polyolefin resin in order from the inner peripheral surface. Whether the second resin layer (A2) is an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol%. If a laminate composed, modified polyolefin resin is preferable.

  The thickness of the outer surface layer (B) of the present invention is such that the thickness of the entire hose soft part [first resin layer (A1) and second resin layer (A2), outer surface layer ( 30 to 90% of the sum of the thicknesses of B)], and more preferably 40 to 67%. When the thickness of the outer surface layer (B) is less than 30% or more than 90% with respect to the thickness of the entire hose soft part, there is a problem that durability of the hose is impaired, which is not preferable.

[Reinforced hard core material (C)]
The resin constituting the reinforced hard core material (C) in the present invention is a hard vinyl chloride resin because it is excellent in coextrusion moldability with the outer surface layer (B) and excellent in adhesiveness or heat-fusibility. Or a hard olefin resin is suitable. The reinforced hard core material (C) is formed in the outer surface layer (B) or spirally wound so as to be exposed to the outside of the outer surface layer (B). Therefore, it is preferable to be exposed to the outside of the outer surface layer (B). Moreover, it is necessary to be excellent in heat fusion and coextrusion with the outer surface layer (B). For example, if the outer surface layer (B) is a soft vinyl chloride resin, the reinforced hard core material (C) is made of a hard vinyl chloride resin. When the outer surface layer (B) is a modified polyolefin resin, a hard olefin resin is preferable.
The hard olefin resin is not particularly limited, and examples thereof include polyethylene resins such as high density polyethylene (HDPE), medium density polyethylene, and low density polyethylene (LDPE), and polypropylene resins such as homopolypropylene, random polypropylene, and block polypropylene. However, block polypropylene is preferable from the viewpoints of heat fusion with the outer surface layer (B), breaking strength, extrusion processability, versatility, and the like.

  The relationship between the repeating unit X (mm) of the convex vertex of the inner peripheral surface and the length Y (mm) between the reinforced hard core material (C) is in the range of 0.90 ≦ X / Y ≦ 1.10. Is preferred. The value of X / Y is more preferably in the range of 0.93 to 1.07 from the viewpoint of the flexibility of the hose, the strength in the radial direction, the pressure resistance, and the range of 0.95 to 1.05. Most preferably. If the value of X / Y is less than 0.90 or exceeds 1.10, the pressure loss of the fluid increases, and the resistance when flowing the fluid increases. The length Y (mm) between the reinforced hard cores (C) is a cross section of the reinforced hard core (C) continuous on the outer surface of the hose or the reinforced hard core (C) when the hose is expanded in the length direction. The length can be obtained by measuring the length of 10 pieces with a caliper having a minimum scale of 0.05 mm and dividing the value by the number of cores 10.

  When the pressure resistance as a hose structure is calculated | required, this invention goods can provide a reinforcing fiber layer as needed. This reinforcing fiber layer can be arbitrarily braided between the first resin layer (A1) / second resin layer (A2) / outer surface layer (B). The reinforcing fiber layer is more preferably braided between the second resin layer (A2) and the outer surface layer (B) from the viewpoint of durability of the hose structure.

  The reinforcing fiber used for this reinforcing fiber layer is composed of two types: a reinforcing fiber in which monofilaments or multifilaments are braided in a net shape, and a reinforcing fiber in which monofilaments or multifilaments are spirally wound along the reinforcing hard core material (C). However, the present invention is not limited to this, and only one of them may be used. Examples of these reinforcing fibers include polyarylate fibers and polyaramide fibers monofilaments or multifilaments made of thermoplastic liquid crystal polymers such as wholly aromatic polyesters, monofilaments or multifilaments of polyester fibers, monofilaments or multifilaments of polyvinyl alcohol fibers, and the like. Among them, polyarylate fibers and polyaramid fibers are preferable in terms of high strength and low elongation.

  Reinforcing fibers braided in a net shape preferably have a knitting angle (angle formed by a horizontal line drawn in the length direction of the hose and the reinforcing fiber) of 25 to 80 degrees, and 30 to 60 degrees from the viewpoint of pressure resistance. More preferably.

Although it is desirable to knit 8 to 96 reinforcing fibers braided in a net shape, the number of knittings may be appropriately set depending on the pressure resistance required for the hose and the size of the inner diameter. For example, the inner diameter ID (mm) is 38 mm. The number of knitting is preferably about 48.
Reinforcing fibers braided spirally along the reinforced hard core material (C) are arranged at regular intervals within a range of 5 to 40 mm so that one yarn follows the reinforced hard core material (C) of the hose. Although it is wound, the interval between the reinforcing fibers may be set as appropriate depending on the length between the reinforcing hard cores (C). For example, the interval between the flexible hoses for gas having an inner diameter ID (mm) of 38 mm is 9 to 10 mm. The degree is preferred.

[Method for producing flexible hose for gas]
As a method for manufacturing the flexible hose for gas of the present invention, for example, on a pipe making machine comprising a cylindrical tube and a spring-shaped rotating rod positioned along the tube surface and inclined with respect to the tube length direction. Although the following forming method to perform is mentioned, it is not specifically limited.
Step (1): The thermoplastic resin constituting the first resin layer (A1) is extruded into a thin tape shape, wound on a pipe making machine in a spiral shape, and its adjacent side edges are fused together. A tubular molded product of one resin layer (A1) is formed.
Step (2): In addition to the first resin layer (A1), when forming the second resin layer (A2), the thermoplastic resin constituting the second resin layer (A2) is the same as in step (1). A tubular molded product in which the second resin layer (A2) is laminated on the outside of the first resin layer (A1) by being extruded into a tape shape and wound so as to cover the first resin layer (A1) Is molded. The first resin layer (A1) and the second resin layer (A2) are supplied from inside and outside the pipe making machine so that the surface temperature immediately before the outer surface layer (B) is wound is 80 ° C. to 150 ° C. Cooling process such as air cooling is performed.
Step (3): On the same pipe making machine as in step (1) and step (2), if necessary, reinforcing fibers are formed in a net form on the first resin layer (A1) or the second resin layer (A2). Further, the reinforcing fibers are spirally wound at a constant interval equal to the repeating unit length of the tubular molded product to form a reinforcing fiber layer.
Step (4): The outer surface layer (B) is formed immediately after braiding the first resin layer (A1) and / or the second resin layer (A2) [possibly immediately after braiding the reinforcing fiber layer]. The thermoplastic resin and the reinforced hard core material (C) are coextruded in a tape shape so as to be exposed or covered from the outer surface layer (B), and the first resin layer (A1) and / or the second resin layer (A2). A hose-like molded body is formed by winding so as to cover the [optional reinforcing fiber layer].
In these steps, the first resin layer (A1), the second resin layer (A2), the outer surface layer (B), and the reinforced hard core material (C) that are extruded from the extruder and cooled on the pipe making machine. By controlling the cooling rate, it is possible to control and form the uneven shape on the inner surface of the hose-shaped molded body. For example, when winding the outer surface layer (B) and the reinforced hard core material (C) in the above step (4) on a pipe making machine, the temperature and flow rate of cooling water from the outside for cooling the hose-shaped molded body The Z / ID value representing the relationship between the depth Z (mm) of the recess between the convex portions on the inner peripheral surface of the hose and the hose inner diameter ID (mm) can be controlled within a preferable range by factors such as the cooling time. it can. Specifically, the temperature after cooling the hose-shaped molded product after the outer surface layer (B) and the reinforced hard core material (C) are wound is in the range of 70 to 100 ° C. on the pipe making machine. Is preferred.

  The gas flexible hose of the present invention is not only small in fluid pressure loss, but also excellent in oil resistance and durability of conventional gas hoses, so that, for example, fields such as civil engineering work, building work, agriculture, etc. Therefore, it can be used for transporting not only gases but also liquids such as highly volatile gasoline, other oils, or volatile organic solvents mixed with powder.

Hereinafter, the present invention will be described more specifically with reference to examples and the like, but the present invention is not limited to the description.
In the following examples and comparative examples, various physical properties were measured and evaluated as follows.

<Pressure loss: Measurement of friction loss coefficient (λ) for straight pipe>
(1) A 3m long hose is installed in a straight tube, and an air blower ("SJF-250-2" manufactured by Suiden Co., Ltd.) is attached to one end of the hose and 0.5m inside from both ends of the hose. Attach a differential pressure gauge by drilling a hole of φ8mm at the location. Next, the air volume generated from the air blower is changed stepwise, and the pressure difference ΔP (Pa) and the corresponding flow velocity V (m / sec) at that time are measured.
(2) Using the value of the equivalent flow velocity V (m / second) measured by the method (1) and the cross-sectional area A (m ² ) of the hose, the value of the air flow rate Q (m ³ / hour) is expressed by the formula (1 ).
Formula (1) Ventilation amount Q = 3,600 × V × A
(3) From the value of the air flow rate Q (m ³ / hour) calculated in the above (2) and the value of the pressure difference ΔP (Pa), the value of the air permeability a (m ³ / hour / Pa ^1/2 ) It calculates according to Formula (2).
Formula (2) Air permeability a = ΔP ^1/2 / Q
(4) The pressure loss coefficient ζ is calculated according to the equation (3) using the value of the air permeability a (m ³ / hour / Pa ^1/2 ) calculated in the above (3).
Formula (3) Pressure loss coefficient ζ = 2 / [ρ (a / 3,600) ² ]
Note that ρ represents the air density (kg / m ³ ).
(5) Using the pressure loss coefficient ζ calculated in (4) above, calculate the friction loss coefficient λ in the straight pipe according to the equation (4).
Formula (4) Friction loss coefficient λ = (ID × ζ) / L
ID represents the hose inner diameter (m), and L represents the hose length (m).
(6) The friction loss coefficient λ in the straight pipe was evaluated according to the following criteria.
A: 0.020 <λ ≦ 0.045 (the friction between the fluid and the inner pipe surface is small, and there is almost no fluid pressure loss)
○: 0.045 <λ ≦ 0.060 (Although there is some friction between the fluid and the inner tube surface, there is no problem with fluid pressure loss when using a hose)
Δ: 0.060 <λ ≦ 0.080 (there is friction between the fluid and the inner tube surface, and a decrease in flow rate due to fluid pressure loss is observed when using a hose)
×: 0.080 <λ (Since the friction between the fluid and the inner pipe surface is large, the pressure loss of the fluid increases when using the hose, which is not suitable for using the hose)

<Measurement of gas barrier properties>
Both ends of a 300 mm long multi-layered hose or tube are tightly caulked with SUS M-1 metal fittings (bamboo nipple shape) and an aluminum outer cylinder, and the caulking part is wound so as to be covered with a plastic paraffin film. One is tightly plugged with seal tape (made of polytetrafluoroethylene), and the other is tightly plugged with a metal fitting having a cock and a metal connector. Through this metal connector, the hose is filled with degassed water with a syringe and left at 23 ° C. for 500 hours. The gas (air) concentration before and after sealing is measured by gas chromatography (AOC manufactured by Shimadzu Corporation). -20I, GC-2010, J), and the increase (ppm) was measured and evaluated according to the following criteria.
○: Gas concentration increase amount is 10 ppm or less. X: Gas concentration increase amount exceeds 10 ppm.

<Measurement of oil resistance>
In the present invention, the resistance to gasoline was evaluated. The evaluation was performed according to the following procedure.
(1) From the 2 mm-thick press sheet of the first resin layer (A1), several samples punched into a JIS No. 3 dumbbell shape are prepared.
(2) Put 100 mL of gasoline (octane number 89.0 or more) into a SUS container with a screw cap with a sufficient volume, and adjust the temperature together with the sample in a 23 ° C. environment for 24 h or more.
(3) The temperature-controlled sample (N = 3) is put into gasoline and immersed for 12 hours at 23 ° C. At the same time, a sample (N = 3) not immersed in gasoline is also prepared under the condition of 23 ° C. At this time, when it swells and gels excessively (the shape cannot be maintained, etc.), the oil resistance is determined as x.
(4) After immersing and after wiping the surface lightly with waste cloth, the breaking strength (MPa) is measured at a tensile speed of 500 mm / min in accordance with JIS K6251.
(5) Using the formula: [Breaking strength after immersion (MPa) / Unbreaking breaking strength (MPa) × 100], the breaking strength retention rate% is calculated.
○: Breaking strength retention% is 90% or more and no swelling / gelation ×: Breaking strength retention% is less than 90% and / or swelling / gelation

Abbreviations and contents relating to materials such as thermoplastic resins used in Examples and Comparative Examples are shown below.
<< The thermoplastic resin which comprised the 1st resin layer (A1), the 2nd resin layer (A2), and the outer surface layer (B) >>
(1) A-1:
Thermoplastic polyurethane [Daiichi Seika Kogyo Co., Ltd. “PX-1-02481”, ester thermoplastic polyurethane, Shore A hardness = 85]
(2) A-2:
・ Ethylene-vinyl alcohol copolymer [“H171B” manufactured by Kuraray Co., Ltd. (ethylene content 38 (mol%), Rockwell surface hardness M = 2])
(3) A-3:
-High density polyethylene [Nippon Polyethylene Co., Ltd. “Novatech HD HY-540, R scale hardness = 70”
(4) A-4:
・ Modified polyolefin resin [Modic AP F534A (unsaturated carboxylic acid-modified polyolefin) manufactured by Mitsubishi Chemical Corporation]
(5) A-5:
・ Soft vinyl chloride resin [“TC2190-4” (Shore A hardness = 66) manufactured by Showa Kasei Kogyo Co., Ltd.]
≪Resin used for reinforced hard core material (C) ≫
C-1: Hard vinyl chloride resin [“PLUS 439” manufactured by Plus-Tech Co., Ltd. (R scale hardness = 90)]
C-2: Block polypropylene [“Novatec PP EA9HD” (R scale hardness = 100) manufactured by Nippon Polypro Co., Ltd.]

<Example 1>
(1) Thermoplastic polyurethane A-1 is extruded into a 30 mm wide tape using a single screw extruder (40 mmφ, cylinder temperature = 160-180 ° C., die temperature = 200 ° C.), and the outer diameter is 50 mm. A tubular molded product as the first resin layer (A1) having a thickness of 0.8 mm was formed by spirally winding on a pipe machine and thermally fusing the adjacent side edges at a temperature of 180 ° C.
(2) Subsequently, the ethylene-vinyl alcohol copolymer A-2 is extruded into a 30 mm wide tape using a single screw extruder (45 mmφ, cylinder temperature = 180 to 190 ° C., die temperature = 230 ° C.). The second resin layer (A2) having a thickness of 0.3 mm was formed so as to cover the first resin layer (A1).
(3) After forming the second resin layer (A2), on the same pipe making machine, the thermoplastic polyurethane A-1 that forms the outer surface layer (B) from the upper surface and the reinforced hard core material (C) Two single-screw extruders (thermoplastic) in which the resin C-1 having a cross-sectional shape is a circle having a diameter of 5 mm and is exposed by a cross die so as to be exposed from the thermoplastic polyurethane A-1 forming the outer surface layer (B) For polyurethane A-1; 65 mmφ, cylinder temperature = 180 to 190 ° C., die temperature = 230 ° C., for resin C-1; 65 mmφ, cylinder temperature = 200 to 220 ° C., die temperature = 230 ° C.) By co-extrusion and winding, a hose-shaped molded article having an inner diameter ID of 50 mm, a length Y between the reinforced hard core materials (C) of 10 mm, and a total thickness of the soft part of 2.3 mm was obtained. .
(4) In the step of obtaining this hose-shaped molded article, the surface temperature of the second resin layer (A2) made of the ethylene-vinyl alcohol copolymer A-2 immediately before winding the outer surface layer (B) is 100 ° C. A cold air of 12 ° C. was applied from inside and outside the pipe making machine. In addition, by applying 7 ° C chiller water from the outside of the pipe making machine to rapidly cool the hose-like molded product on the pipe making machine to 80 ° C, it is removed from the pipe making machine and further cooled, so that the convex portion on the inner peripheral surface The vertex repeating unit X (mm) was 10 mm, and the relationship Z / ID between the recess depth Z (mm) between the convex portions on the inner peripheral surface of the hose and the hose inner diameter ID (mm) was adjusted to 0.026.
The performance evaluation is shown in Table 1.

<Example 2>
(1) Dry blend the thermoplastic polyurethane A-1 and the ethylene-vinyl alcohol copolymer A-2 with a mixing tumbler so that the mixing ratio is 20:80. The resin mixture after the dry blending was subjected to the same steps as in Example 1 to form a tubular molded product as the first resin layer (A1) having a thickness of 0.8 mm.
(2) After forming the first resin layer (A1), on the pipe making machine, the soft vinyl chloride resin A-5 and the reinforcing hard core material (C) forming the outer surface layer (B) from the upper surface are formed. Two single-screw extrusions made of hard vinyl chloride resin C-1 formed by a cross die so as to be enclosed in a soft vinyl chloride resin A-5 having a circular cross section of 5 mm in diameter and forming the outer surface layer (B) By co-extrusion into a tape shape using a machine and winding, the inner diameter ID is 50 mm, the length Y between the reinforced hard core materials (C) is 10 mm, and the total thickness of the soft part is 6.8 mm. A hose-shaped molded product was obtained.
(3) In the step of obtaining this hose-shaped molded article, a first resin layer (including thermoplastic polyurethane A-1 and ethylene-vinyl alcohol copolymer A-2) immediately before winding the outer surface layer (B) ( Cold air of 12 ° C. was applied from inside and outside the pipe making machine so that the surface temperature of A1) was 80 ° C. In addition, by applying 7 ° C. chiller water from the outside of the pipe making machine and rapidly cooling the hose-shaped molded product on the pipe making machine to 60 ° C., by removing it from the pipe making machine and further cooling with 7 ° C. chiller water, The repeating unit X (mm) of the convex portion apex on the inner peripheral surface is 10 mm, and the relationship Z / ID between the concave depth Z (mm) between the convex portions on the inner peripheral surface of the hose and the hose inner diameter ID (mm) is 0. Adjusted to 008.
The performance evaluation is shown in Table 1.

<Example 3>
(1) The inner peripheral surface is high-density polyethylene A-3, and the modified polyolefin resin A-4 is formed into a tape having a width of 30 mm using two single-screw extruders joined with a cross die so as to cover the upper surface. By co-extrusion and winding, a tubular molded product as the first resin layer (A1) having a thickness of 0.6 mm (A-3 layer: 0.3 mm, A-4 layer 0.3 mm) was formed.
(2) Subsequently, the ethylene-vinyl alcohol copolymer A-2 is extruded using a single screw extruder into a tape having a width of 30 mm so that the first resin layer (A1) is covered with a thickness of 0. A 3 mm second resin layer (A2) was formed.
(3) After the second resin layer (A2) is formed, the modified polyolefin resin A-4 that forms the outer surface layer (B) from the upper surface and the reinforced hard core material (C) are formed on the pipe making machine. Tape using two single-screw extruders in which resin C-2 is circular with a cross-sectional shape of 5 mm in diameter and joined with a cross die so as to be exposed from modified polyolefin resin A-4 forming the outer surface layer (B) A hose-shaped molded article having an inner diameter ID of 50 mm, a length Y between the reinforced hard core materials (C) of 10 mm, and a total thickness of the soft part of 2.3 mm is obtained by co-extrusion and winding. Obtained.
(4) In the step of obtaining the hose-shaped molded product, from the inside and outside of the pipe making machine so that the surface temperature of the second resin layer (A2) immediately before winding the outer surface layer (B) becomes 110 ° C. A cold air of 12 ° C. was applied. Also, after applying 7 ° C chiller water from the outside of the pipe making machine to 80 ° C, the hose-shaped molded product on the pipe making machine is removed from the pipe making machine and further cooled with 7 ° C chiller water. The repeating unit X (mm) of the convex portion vertex of the peripheral surface is 10 mm, and the relationship Z / ID between the concave depth Z (mm) between the convex portions of the inner peripheral surface of the hose and the hose inner diameter ID (mm) is 0.050. Adjusted.
The performance evaluation is shown in Table 1.

<Comparative Example 1>
(1) to (2) A tubular molded product is formed through the same steps as in Example 1.
(3) After forming the second resin layer (A2), the thermoplastic polyurethane A-1 forming the outer surface layer (B) from the upper surface is coextruded into a 30 mm width tape on the pipe making machine, and wound. As a result, a hose-shaped molded product having an inner diameter ID of 50 mm and a total thickness of the soft part of 4.5 mm was obtained.
(4) In the step of obtaining this hose-shaped molded product, the special cooling step as performed in <Example 1> was not performed, and a tubular molded product was molded in a room temperature (23 ° C.) environment. Moreover, after winding the outer surface layer (B), it was gradually cooled using 21 ° C. factory water. As a result, it can be seen that the inner peripheral surface of the hose has almost no unevenness even when touched with a fingertip and observed, and the relationship between the recess depth Z (mm) between the portions and the hose inner diameter ID (mm) A tubular molded article having a Z / ID of less than 0.001 was obtained.

<Comparative Example 2>
(1) to (3) A tubular molded product is formed through the same steps as in Example 3.
(4) In the step of obtaining the hose-shaped molded product, the special cooling step as in Example 3 is not performed, and the tubular molded product is molded in a room temperature (23 ° C.) environment, and the outer surface layer (B) is removed. The surface temperature of the second resin layer (A2) immediately before the rotation was 140 ° C. Also, from the outside of the pipe making machine, 21 ° C. factory water is applied and the hose-shaped molded product on the pipe making machine is gradually cooled to around 110 ° C. and then removed from the pipe making machine and cooled in the same manner. The repeating unit X (mm) of the convex portion apex of the peripheral surface is 10 mm, and the relationship Z / ID between the concave depth Z (mm) between the convex portions on the inner peripheral surface of the hose and the hose inner diameter ID (mm) is 0.070. Adjusted.
The performance evaluation is shown in Table 1.

  As is clear from the results in Table 1, the relationship Z / ID between the depth Z (mm) of the recess between the convex portions and the hose inner diameter ID (mm) on the inner peripheral surfaces of Comparative Examples 1 and 2 is Z / ID. The flexible hose for gas satisfying ID <0.003 or 0.05 <Z / ID is not possible because the friction loss coefficient λ during straight pipe is 0.060 <λ and the pressure loss increases.

  The gas flexible hose of the present invention is a flexible hose that has a small fluid pressure loss and is excellent in gas barrier properties and oil resistance. For example, it can be used not only for intake and exhaust of highly volatile oil such as gasoline. It can be beneficially used for the transportation of powder or mixed gas of powder.

The whole figure of the structure where the reinforcement hard core material (C) which exposes an example of the flexible hose for gas of this invention from the outer surface layer (B), and the schematic diagram of a partial cross section. The schematic diagram which expanded the cross section of FIG. The whole figure and partial schematic diagram of the structure where the reinforcement hard core material (C) showing an example of the flexible hose for gas of this invention is embedded in the outer surface layer (B). The schematic diagram which expanded the cross section of FIG. The cross section of the two-layer laminate co-extruded so that the first resin layer (A1) of the flexible hose for gas becomes a polyolefin resin / modified polyolefin resin in order from the inner peripheral surface was enlarged. Pattern diagram.

A1 1st resin layer A2 2nd resin layer B Outer surface layer C Reinforcement hard core X Repeat unit of convex vertex of hose inside (mm)
Y Length between reinforced hard core (D) (mm)
Z Depth of recess between convex parts inside hose (mm)
ID hose inner diameter (mm)
PO Polyolefin resin modified PO Modified polyolefin resin

Claims (6)

In order from the inner surface of the hose, the first resin layer (A1) / the second resin layer (A2) / the outer surface layer (B) / the reinforced hard core material (C). The following conditions (1) and (2) are satisfied. A flexible hose for gas that fills everything.
(1) When deployed in the length direction of the hose, when X (mm) is the repeating unit of the convex portion apex on the inner peripheral surface, 5 mm ≦ X ≦ 25 mm,
(2) When the depth of the recess between the convex portions on the inner peripheral surface of the hose is Z (mm) and the inner diameter of the hose is ID (mm), 0.003 ≦ Z / ID ≦ 0.05.   The first resin layer (A1) is composed of a single layer of thermoplastic polyurethane, and the second resin layer (A2) is composed of an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60 mol%. Flexible hose for gas.   The flexible hose for gas according to claim 1, wherein the first resin layer (A1) is a single layer made of a resin composition in which an ethylene-vinyl alcohol copolymer and a thermoplastic polyurethane are mixed.   The first resin layer (A1) is a two-layer laminate co-extruded so as to be a polyolefin resin / modified polyolefin resin in order from the inner peripheral surface, and the second resin layer (A2) has an ethylene content. The flexible hose for gas according to claim 1, which is an ethylene-vinyl alcohol copolymer in an amount of 20 to 60 mol%.   The flexible hose for gas according to claims 1 to 4, wherein the reinforcing hard core material (C) is made of a hard vinyl chloride resin or a hard polyolefin resin. When the length between the reinforced hard core materials (C) is Y (mm), the relationship between the above-mentioned convex vertex of the inner peripheral surface and the repeating unit X (mm) is 0.90 ≦ X / Y ≦ 1. The gas flexible hose according to claim 1, wherein the gas flexible hose is satisfied.