JP2000025121A - Manufacture of flexible hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a flexible hose with high productivity comprising a multilayer structure having a bellows shaped resin layer as an outermost layer and a rubber layer as an external surface layer of the resin layer. SOLUTION: A resin material 2a constituted of a resin layer around a rod- shaped mandrel and an intermediate rubber layer 3 are laminated in order, a heat shrinkage member 6 is laminated to correspond to the bellows shaped irregularity pitch on the intermediate rubber layer 3, and a reinforcing thread layer 4 and an external surface rubber layer 5 is then laminated thereon in order, so as to form a laminate 8. Subsequently, in the condition where an internal pressure is applied in the resin material 2a which has a space by extracting the mandrel 7 from the laminate 8, the laminate 8 is heated, the rubber layer 3 is vulcanized, and the heat shrinkage member 6 is contracted, so as to form a bellows shaped resin layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a flexible hose having a multilayer structure having a resin layer as an innermost layer, and more particularly to a method for manufacturing a hose for fluid transport requiring low gas permeability and flexibility. It is suitable for use.

[0002]

2. Description of the Related Art Conventionally, as a hose of this type, there is a low gas permeable flexible hose having a resin layer in an innermost layer which is an inner surface of the hose. This utilizes the fact that a resin has a smaller gas permeation amount than a rubber, but generally has a disadvantage that a resin having a small gas permeation is harder than a rubber and does not have sufficient flexibility.

In particular, in recent years, from the viewpoint of global environmental protection, H
There is a need for a hose that minimizes the amount of permeation of a refrigerant gas such as FC-134a. Therefore, although a hose having the above-described resin layer has been put to practical use, its flexibility is inferior to that of a rubber hose. As a solution to such a problem, the present applicant has previously filed Japanese Patent Application No. 9-56491,
A refrigerant hose in which the resin layer has a bellows shape to improve flexibility has been proposed. As shown in FIG. 1, a bellows-shaped resin layer 2 as the innermost layer and a reinforcing layer (reinforcing thread layer) 4 as an outer layer of the resin layer 2 are interposed from the inside of the refrigerant hose 1 as shown in FIG. And two rubber layers 3 and 5.

[0004]

However, when the above-mentioned prior application was examined, it was found that the following problems occurred. That is, in the prior application, the bellows shape is formed by molding the resin layer 2 using a rod-shaped core material (mandrel) 7a having irregularities corresponding to the bellows shape on the outer surface. Here, after molding, it was found that the core material 7a had to be removed while rotating or the like, and it was difficult to remove the core material 7a, so that it took a long time, and it was found that there was a problem in productivity.

In view of the above, the present invention provides a flexible hose having a multi-layer structure having a bellows-shaped resin layer as an innermost layer and a rubber layer as an outer layer of the resin layer with high productivity. It is intended to provide a manufacturing method.

[0006]

Means for Solving the Problems The present invention has been made by paying attention to the fact that the rubber constituting the rubber layer as the outer surface layer of the resin layer has a property that it liquefies during vulcanization and the fluidity increases. It is. That is, according to the first aspect of the present invention, a resin material (2a) constituting a resin layer (2) is laminated around a rod-shaped core material (7), and a rubber layer (3) is formed therearound.
Are laminated on the rubber layer (3) to form a laminate (8) by laminating a heat-shrinkable member (6) so as to correspond to the bellows-like uneven pitch. Core material (7)
The laminate (8) is heated in a state where internal pressure is applied to the resin material (2a) which has become a space by removing the rubber material, thereby vulcanizing the rubber layer (3) and shrinking the heat-shrinkable member (6). Thus, a bellows shape of the resin layer (2) is formed.

When the laminate (8) is heated while the internal pressure is applied to the resin material (2a) after the core material (7) is removed, the rubber layer (3) is liquefied by vulcanization and flows. In addition, the resin material (2a) receives a force inside the hose due to the contraction of the heat-shrinkable member (6), and the resin material (2a) in the portion where the heat-shrinkable member (6) does not exist is forced out of the hose by the internal pressure. Since the resin material (2a) receives the force, the resin material (2a) is deformed in a wave shape, and forms a resin layer (2) having a bellows shape.

As described above, according to the present invention, the bellows-shaped resin layer (2) can be formed after the core material (7) is pulled out, so that the core material (7) has a shape corresponding to the bellows shape. For example, a round bar-shaped material having no core material can be used, and the core material (7) can be easily removed. Therefore, according to the present invention, it is possible to provide a manufacturing method capable of manufacturing a flexible hose with high productivity.

Here, as the heat-shrinkable member (6), a heat-shrinkable resin can be used as in the invention of claim 2, and more specifically, polyethylene and 6 nylon having a large shrinkage rate. , 66 nylon. According to the third aspect of the present invention, the reinforcing yarn layer (4) made of braided yarn is laminated on the rubber layer (3) on which the heat-shrinkable member (6) is laminated to form a laminate ( 8), the entire hose can be reinforced, and a force for deforming the resin material (2a) can be applied without escaping to the outside of the hose, so that a uniform bellows shape can be formed. .

The above-mentioned reference numerals in parentheses are examples showing the correspondence with specific means described in the embodiment described later.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. In the present embodiment, the present invention is used for piping of a cooling and heating device or the like, and the inside thereof is made of chlorofluorocarbon (for example, HFC-
An example in which the present invention is applied to a refrigerant hose (cooler hose) through which a refrigerant gas such as 134a) flows. The configuration of the refrigerant hose 1 of the present embodiment will be described with reference to FIG.

The refrigerant hose 1 is composed of multiple layers. The layer structure is such that a bellows-shaped (spiral in this example) resin layer 2 is the innermost layer, and an intermediate rubber layer (first rubber layer) is provided on the outer side.
3, a reinforcing yarn layer 4, and an outer rubber layer (second rubber layer) 5 are sequentially laminated. Here, each adjacent layer is bonded to each other by vulcanizing the rubber of each of the rubber layers 3 and 5 using an adhesive.

The resin layer 2 is formed of a resin through which a refrigerant hardly permeates, for example, an aromatic polyamide synthetic resin such as 6-nylon. Its thickness is, for example, 100 to 1
It is 50 μm, and has a thickness that does not easily allow the refrigerant to permeate. The resin layer 2 has a bellows shape, and the unevenness of the bellows is spiral. Due to the expansion and contraction action of the bellows, the innermost resin layer 2 can expand and contract without load according to the expansion and contraction of the rubber layers 3 and 5 of the outer surface layer when the refrigerant hose 1 is bent or pulled.

Here, in order to more effectively exert the stretching action of the bellows, the bellows pitch is 0.05 to 5 mm, and the height of the bellows (the difference between the height of the concave portion and the convex portion of the bellows) is zero. .05-
It is preferably 5 mm. That is, if the pitch and height are too small, the bellows expand and contract insufficiently, and if the height is too large, the pressure loss of the refrigerant in the hose becomes large due to the resistance of the unevenness of the bellows.

The two rubber layers 3 and 5 (for example, each having a thickness of 1.2 to 1.5 mm) are made of an elastic member such as synthetic rubber to secure the flexibility of the hose against bending and the like. . The rubber layers 3 and 5 are not particularly limited as long as they can be vulcanized. For example, the intermediate rubber layer 3 is made of butyl rubber or the like, and the outer rubber layer 5 is made of EPDM.
(Ethylene propylene dimonomer).

Although not shown in FIG. 1, as shown in FIG. 3, which will be described later, the heat-shrinkable material is located near the resin layer 2 in the intermediate rubber layer 3 or at the interface between the intermediate rubber layer 3 and the resin layer 2. The heat-shrinkable member 6 made of the above resin is interposed. The heat-shrinkable member 6 is spirally disposed around the resin layer 2 corresponding to a concave portion of the thermal resin layer 2 which is concave in the direction of the central axis 10 of the inner diameter of the hose.

Here, as the heat-shrinkable resin, polyethylene having a large shrinkage (shrinkage: 15 × 10 ⁻³ to 50 × 1)
0 ^-3) polyolefin or the like, 6 nylon (Shrinkage 9
For example, polyamides such as × 10 ⁻³ ) and 66 nylon (shrinkage ratio: 15 × 10 ⁻³ ) can be used. The heat-shrinkable member 6 may be a member that shrinks at a vulcanization temperature (for example, 150 ° C. to 180 ° C.) described below, and may be another organic material, a metal, an inorganic material, or a mixed material thereof.

The reinforcing yarn layer 4 is made of a braided resin yarn and ensures the strength of the hose against pulling and the like. Here, the reinforcing yarn layer 4 is
For example, PET (polyethylene terephthalate) or aramid of about 2000 to 4000 denier (D, 1D is 1 gram / 9000 m) is used. The two rubber layers 3 and 5 have a reinforcing yarn layer 4 interposed therebetween.
One rubber layer.

Next, a method of manufacturing the refrigerant hose 1 having such a configuration will be described with reference to FIGS. FIG. 3 is an explanatory view of the formation mechanism of the bellows shape. The center axis 10 of the hose inner diameter before and after vulcanization of the refrigerant hose 1 is shown.
2 shows a cross section taken along the line. First, as shown in FIG. 2, a round bar-shaped mandrel 7 made of resin (or rubber) is prepared as a core material. The mandrel 7 may be a hollow pipe.

Then, a resin material 2a constituting the resin layer 2 is laminated around the mandrel 7 by extrusion molding or the like. Subsequently, the intermediate rubber layer 3 is laminated thereon by extrusion molding or the like, and the heat-shrinkable member 6 is wound thereon so as to correspond to the above-mentioned spiral uneven pitch (see FIG. 3). Then, after braiding and laminating the reinforcing yarn layer 4 thereon,
The outer rubber layer 5 is laminated by extrusion molding or the like to form a laminate 8 shown in FIG.

Subsequently, after the mandrel 7 is removed from the laminate 8 by water pressure or the like, an internal pressure is applied to the resin material 2a which has become a space. Here, the internal pressure is equal to
Is sealed at one end and steam pressure, compressed air pressure, hydraulic pressure, etc. are applied from the other end. Then, with the internal pressure applied, the laminate 8 is heated (for example, 150 ° C. to 180 ° C.), and the rubber layers 3 and 5 are vulcanized.

At this time, as shown in FIG. 3, the rubber layer 3 is liquefied by vulcanization to increase the fluidity, and the heat-shrinkable member 6 contracts and moves toward the center axis 10 of the hose inner diameter. The resin material 2a receives a force inside the hose by the heat-shrinkable member 6 (upward arrow A), and the resin material 2a in a portion where the heat-shrinkable member 6 does not exist receives a force outside the hose by the internal pressure (downward arrow B). As a result, the resin material 2a also undergoes creep due to the heat of vulcanization and is deformed in a wavy manner, thereby forming the resin layer 2 having a bellows shape.

Further, the respective layers are adhered by vulcanization of the rubber layers 3 and 5, whereby the refrigerant hose 1 is completed. By the way, according to the present embodiment, after the mandrel 7 is pulled out,
Since the bellows-shaped resin layer 2 can be formed, a mandrel 7 that does not have a shape corresponding to the bellows shape, for example, a commonly used round bar can be used. Therefore, for example, as described above, the hose can be easily removed by water pressure, and the hose can be manufactured with high productivity.

According to the present embodiment, the entire hose can be reinforced by the reinforcing yarn layer 4 and the resin material 2
The force for deforming a can be applied without escaping to the outside of the hose, and a uniform bellows shape can be efficiently formed. Further, according to the present embodiment, low gas permeability can be realized by the resin layer 2, and the resin layer 5 has the same expansion and contraction performance as the rubber layers 2 and 4 due to expansion and contraction of the bellows. 1. Overall flexibility can be improved.

As described above, according to this embodiment, a mandrel 7 can be easily pulled out, a flexible hose having high productivity, and having both flexibility and low gas permeability can be provided. If the strength of the hose can be ensured, the reinforcing thread layer 4 may not be provided, and the outer rubber layer 5 thereon may not be provided.

The bellows shape of the resin layer 2 does not have to be spiral, and a ring-shaped concave portion which is depressed in the direction of the central axis 10 around the outer diameter of the resin layer 2 is formed along the longitudinal direction of the resin layer 2. It may be arranged at a pitch and provided with irregularities. In this case, the heat-shrinkable member 6 is not continuous spirally,
A structure in which a plurality of the ring-shaped concave portions are arranged in accordance with each individual ring-shaped concave portion. In the case of the spiral shape, since the heat-shrinkable member 6 is a continuous and integral one, there is an advantage that the heat-shrinkable member 6 is unlikely to be displaced when the laminated body 8 is formed or vulcanized.

The present invention is not limited to refrigerant hoses, but can be applied to hoses for transporting fluids such as air, water and oil.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view of a flexible hose having a bellows-shaped resin layer as an innermost layer.

FIG. 2 is an explanatory diagram illustrating a manufacturing method according to the embodiment of the present invention.

FIG. 3 is an explanatory view showing a mechanism of forming a bellows shape of a resin layer of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Refrigerant hose, 2 ... Resin layer, 2a ... Resin material, 3 ... Intermediate rubber layer, 4 ... Reinforcement thread layer, 6 ... Heat shrinkable member, 7 ... Mandrel, 8 ... Laminate.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16L 11/11 F16L 11/11 // B29K 21:00 105: 24 F term (reference) 3H111 AA02 BA11 BA15 CA44 CB03 CB04 CB05 CB10 CC02 CC06 CC07 DA26 DB09 EA12 4F100 AK01A AK09B AK09J AK28B AK28J AK42B AK46A AK47B AK75C AL01B AN00B AN00C AN02B BA03 CA23B DA13 DD12B DG01B18 AGAJA GBA AJB GBA GBA JA18 DL14 4F210 AA09 AA30 AA46 AD16 AD18 AD25 AG10 AG28 RC03 RG01 RG07 RG09 RG22 RG54 4F213 AA09 AA30 AA46 AD16 AD18 AG10 AG25 AG28 WA06 WA13 WA43 WA54 WA87 WB01 WC02

Claims (3)

[Claims] 1. A method for manufacturing a flexible hose (1) having at least a bellows-shaped resin layer (2) as an innermost layer and a rubber layer (3) as an outer layer of the resin layer (2). The resin material (2a) constituting the resin layer (2) is laminated around the rod-shaped core material (7), and the rubber layer (3) is laminated around the laminated resin material (2a). Then, a heat-shrinkable member (6) is laminated on the rubber layer (3) so as to correspond to the pitch of the bellows-like unevenness to form a laminate (8). From the laminate (8), the core is formed. After removing the material (7), the laminate (8) is heated in a state where internal pressure is applied to the resin material (2a) which has become a space thereby to vulcanize the rubber layer (3). Manufacturing the flexible hose by shrinking the heat-shrinkable member (6). Law. 2. The method according to claim 1, wherein a heat-shrinkable resin is used as the heat-shrinkable member. 3. A reinforcing yarn layer (4) made of braided yarn is laminated on the rubber layer (3) on which the heat shrinkable member (6) is laminated, and the laminated body (8) is formed. The method for manufacturing a flexible hose according to claim 1 or 2, wherein