JP2001200961A - Composite flexible hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite flexible hose capable of remarkably reducing permeation of gas and usable in common with R12 and R134a refrigerants without arranging an adhesive layer by enabling stable strong adhesion between the inmost layer of an inner tube and an intermediate resin layer (a barrier layer). SOLUTION: After laminating the inmost layer 2 by blending 10 to 50 pts.wt. of a silicic acid or its salt, 5 to 20 pts.wt. of an epoxy resin, 0.5 to 5 pts.wt. of a phenol resin and 0.5 to 5 pts.wt. of methylolmelamine with 100 pts.wt. of chloroprene rubber, the intermediate resin layer 3 by blending polyamide and carboxyl group including modified polyolefine, an inner tube outer layer rubber layer 4 of chloroprene rubber, a fiber reinforcing layer 5 and an outside surface rubber layer 6, these layers are heated to be vulcanized and adhered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composite flexible hose, and more particularly to a composite flexible hose suitable for transporting a refrigerant.

[0002]

2. Description of the Related Art As shown in FIG. 2, a composite flexible hose used for transporting a refrigerant gas for a car air conditioner and a refrigerant gas for a contact freezer is usually provided with an innermost layer 2, an adhesive layer 7, an intermediate layer, and so on in order from the inside. It is formed by laminating a rubber layer 8, a fiber reinforcing layer 5, and an outer rubber layer 6 (Japanese Patent Laid-Open No. 1-110143), and a polyamide resin is generally used for the innermost layer 2 in order to secure gas barrier properties. Used in

However, from the viewpoint of protection of the ozone layer, R134a is used as a refrigerant for car air conditioners in Japan, and polyalkylene glycol is used as a lubricating oil for a compressor due to its compatibility with the refrigerant.
For the purpose of improving lubrication properties, additives having high activity may be used in some cases. Under the influence, the polyamide of the innermost layer 2 may be deteriorated during use, leading to cracks.

As a countermeasure against the oil, the innermost layer 2
It is conceivable to use a low gas permeable rubber hose (JP-A-10-47552) in which a scale-like filler is added to an IIR rubber. However, from a worldwide perspective, many countries use R12 refrigerant, and IIR is not applicable because mineral oil used as a lubricant for R12 refrigerant significantly lubricates mineral oil.

[0005] As a structure which can be used in common for the R12 and R134a refrigerants and which significantly reduces gas permeation, an inner tube in which chloroprene rubber is provided on the innermost layer, a polyamide resin is provided on the outer side, and a rubber layer is provided on the outer side. Although a hose having a three-layer structure is also used, in the composite flexible hose of this shape, the polyamide layer, which is an intermediate barrier layer, transmits less refrigerant than the innermost rubber layer. Since the refrigerant that has passed through is accumulated in the polyamide layer and swelling is likely to occur, it is necessary to make the interlayer adhesion between the layers particularly strong.

[0006] In this regard, conventionally, the innermost layer of chloroprene rubber and polyamide have been bonded via an adhesive layer. As the adhesive used for the adhesive layer, a phenolic resin, a mixture of a phenolic resin and an elastomer, a halogenated polyolefin, or a chlorinated rubber solvent-type adhesive is used.

However, when a solvent-type adhesive is used, it takes time for the solvent to evaporate and the working environment is deteriorated. Further, the formation of the adhesive layer itself involves an increase in the number of steps and cost.

[0008]

A method for bonding a rubber layer and a polyamide without an adhesive layer is disclosed in Japanese Patent Application Laid-Open No. 10-161.
No. 38 and Japanese Unexamined Patent Publication No. Hei 7-117178 have been filed earlier, but all of them are based on IIR rubber, and good results were not obtained even when applied to chloroprene rubber. .

The present invention provides a composite flexible hose that can be used in common for the R12 and R134a refrigerants and has significantly reduced gas permeation.

[0010]

Means for Solving the Problems The inventors of the present invention have studied to solve the above problems, and have provided a chloroprene-based rubber layer on the innermost layer, a polyamide-based resin layer on the outer layer, and a rubber layer on the outer layer. The hose having an inner tube three-layer structure can be used in common for R12 and R134a refrigerants, and has a structure in which gas permeability is extremely low. The innermost layer is made of a rubber obtained by compounding a chloroprene-based rubber with a specific additive. It has been found that by forming the composition, stable and strong adhesion can be obtained without providing an adhesive between the innermost layer of the chloroprene rubber layer and the barrier layer of the polyamide resin layer, and completed the present invention.

According to the present invention, an innermost layer, an intermediate resin layer,
An inner tube outer layer rubber layer, a fiber reinforcing layer and an outer rubber layer are laminated in this order, and the innermost layer is composed of 10 to 50 parts by weight of silicic acid or a salt thereof and 100 parts by weight of chloroprene-based rubber, 20 parts by weight, 0.5 parts of phenol resin
-5 parts by weight and 0.5-5 parts by weight of methylol melamine, wherein the intermediate resin layer is made of a modified polyamide obtained by blending a polyamide and a carboxyl group-containing modified polyolefin. The present invention relates to a composite flexible hose in which the outer rubber layer is made of chloroprene-based rubber, and the innermost layer, the intermediate resin layer, and the inner tube outer rubber layer, which are obtained by heating (vulcanizing) after laminating the respective layers, have no adhesive.

According to the present invention, the modified polyamide is preferably made of polyamide 6, polyamide 11, polyamide 12, polyamide 4-6, polyamide 6-6, polyamide 6-10, polyamide 6-12 and polyamide MX.
The present invention relates to the above-mentioned composite flexible hose, which is a polyamide selected from the group consisting of D-6 or a polyamide consisting of a copolymer containing at least two kinds of constituent components.

[0013]

FIG. 1 shows a laminated structure of a composite flexible hose according to the present invention. The composite flexible hose 1 of the present invention is formed by laminating an innermost layer 2, an intermediate resin layer 3, an inner tube outer layer rubber layer 4, a fiber reinforcement layer 5, and an outer surface rubber layer 6 in this order from the inside. The composite flexible hose 1 of the present invention has no adhesive layer between the innermost layer 2 and the intermediate resin layer 3, and has an inner tube outer layer rubber layer 4, a fiber reinforcing layer 5, It has an outer rubber layer 6.

In the present invention, the innermost layer 2 is formed on the chloroprene rubber with silicic acid or a salt thereof, an epoxy resin,
The intermediate resin layer 3 is made of a modified polyamide obtained by blending a polyamide and a carboxyl group-containing modified polyolefin, and the inner tube outer layer rubber layer 4 is made of chloroprene. By using a rubber based material (preferably, a chloroprene rubber containing silicic acid or a salt thereof, an epoxy resin, a phenol resin and methylolmelamine), a strong adhesive force can be obtained without providing an adhesive layer.

That is, the functional groups (carboxyl group, amide group, amino group, etc.) in the modified polyamide constituting the intermediate resin layer 3 and the halogen groups of the chloroprene rubber constituting the innermost layer 2 and the inner tube outer layer rubber layer 4 Or a silanol group of silicic acid or a salt thereof, an epoxy group of an epoxy resin, a phenol group of a phenol resin and an amino group of methylolmelamine, or a halogen of a chloroprene rubber constituting the inner and outer rubber layers 4. This is presumed to be because the group improves the wettability at the interface of the adhesive layer, causes a complicated reaction between the functional groups, and causes various bonds.

The innermost layer 2 is made of a rubber composition obtained by mixing silicic acid or a salt thereof, an epoxy resin, a phenol resin and melamine with a chloroprene rubber. As the chloroprene rubber, BR and S are used as processing aids for chloroprene rubber and 100 parts by weight of chloroprene rubber.
BR or EPDM may be used alone or in a combination of a plurality of them at a ratio of 7 parts by weight or less. If the processing aid is used in an amount of 7 parts by weight or more, the adhesive strength tends to decrease.

In the present invention, the silicic acid or a salt thereof includes, for example, silicic anhydride, hydrous silicic acid, hydrous calcium silicate, and hydrous aluminum silicate. Hydrous silicic acid having many silanol groups is preferred. Silicic acid or a salt thereof is extremely reactive and acts to increase the bonding strength by hydrogen bonding with a modified polyamide or chloroprene rubber.

The silicic acid or a salt thereof is blended in an amount of 10 to 50 parts by weight, preferably 15 to 30 parts by weight, particularly preferably 20 to 30 parts by weight, based on 100 parts by weight of the chloroprene rubber. If the amount of the silicic acid or salt thereof is less than 10 parts by weight based on 100 parts by weight of the chloroprene rubber, the adhesiveness tends to be poor. Tends to be the cause.

In the present invention, as the epoxy resin,
For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, cyclic fatty epoxy resin, novolak epoxy resin and the like can be used, and specifically, Epicoat 82 manufactured by Yuka Shell Epoxy Co., Ltd.
8, epicoat 815 and the like. The epoxy resin not only functions as an adhesive component, but also acts as an acid acceptor for dehydrochlorination of the chloroprene rubber.

Epoxy resin is chloroprene rubber 10
5 to 20 parts by weight, preferably 10 to 1 part by weight per 0 parts by weight
Add 5 parts by weight. If the amount of the epoxy resin is less than 5 parts by weight per 100 parts by weight of the chloroprene rubber, the adhesiveness tends to be poor, and if it is more than 20 parts by weight, adhesion to processing equipment at the time of kneading and extrusion molding, Workability tends to be worse.

In the present invention, examples of the phenolic resin blended as the adhesion improving component include 2,6-dimethylol-p-cresol, resole type phenolic resin and novolak type phenolic resin.
Sumikanol 620 is preferred from the viewpoint of good adhesive strength and reactivity with methylolmelamine.

The phenol resin is chloroprene rubber 1
0.5 to 10 parts by weight, especially 1 to 5 parts by weight
It is preferred to use parts by weight. If the amount of the phenolic resin is less than 0.5 part by weight based on 100 parts by weight of the chloroprene rubber, the effect of improving the adhesive strength tends not to be obtained, and if it exceeds 10 parts by weight, the physical properties of the rubber composition deteriorate. Tend.

In the present invention, as the methylol melamine to be blended as the adhesion improving component, Sumikanol 508 and Sumikanol 507A manufactured by Sumitomo Chemical Co., Ltd. can be mentioned. Sumikanol 50
7A is preferred.

Methylol melamine is added in an amount of 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the chloroprene rubber. If the amount of methylol melamine is less than 0.5 part by weight based on 100 parts by weight of the chloroprene rubber, the effect of improving the adhesive strength tends not to be obtained, and if it exceeds 10 parts by weight, the physical properties of the rubber composition deteriorate. Tend.

In addition to the rubber composition for the innermost layer 2, an appropriate amount of stearic acid, a plasticizer, an antioxidant, a processing aid and the like may be added.

The innermost layer 2 is formed by extruding to a thickness of usually 0.5 to 2.2 mm, preferably 0.8 to 1.5 mm.

In the present invention, the intermediate resin layer 3 is made of a modified polyamide obtained by blending a polyamide and a carboxyl group-containing modified polyolefin.
1, polyamide 12, polyamide 4-6, polyamide 6
-6, polyamide 6-10, polyamide 6-12, polyamide MXD-6, and a polyamide containing at least two kinds of constituent components. As polyamide, heat resistance, cost,
Polyamide-6 is preferred from the viewpoint of processability and the like.

Examples of the carboxyl group-containing modified polyolefin include olefins such as ethylene, propylene and butadiene and polyolefins obtained by homopolymerization or copolymerization of diene monomers, and acid anhydrides such as acrylic acid, methacrylic acid, maleic acid and fumaric acid. A modified polyolefin in which about 0.1% to 10% by mole of a functional group is introduced by graft polymerization of a polyolefin is preferably used.

The blend ratio (weight ratio) between the polyamide and the modified polyolefin is 90/10 to 50/50, preferably 65
/ 35 to 55/45 are preferred. When the proportion of the modified polyolefin increases, the hose becomes more flexible but the refrigerant permeation resistance is inferior, and when it becomes smaller, the refrigerant permeation resistance improves but the adhesiveness and flexibility with the innermost layer and the inner tube outer layer rubber layer tend to be inferior. is there.

The intermediate resin layer 3 is obtained by extruding the modified polyamide into a tube. The thickness of the tube is preferably 0.05 mm or more from the viewpoint of molding workability and resistance to refrigerant permeation. From the viewpoint, it is preferably 0.5 mm or less.

In the present invention, the intermediate resin layer 3 is formed directly on the innermost layer 2. Therefore, since the step of forming the adhesive layer is omitted, the time required for evaporating the solvent is not required, and the entire process can be shortened. The formation of the intermediate resin layer 3 can be performed by directly extruding the modified polyamide on the outer surface of the innermost layer 2.

As the chloroprene rubber constituting the inner tube outer layer rubber layer 4, a rubber composition constituting the innermost layer can be used.

The thickness of the outer rubber layer 4 is 0.3 to 1.5.
mm is preferable. If the thickness of the inner tube outer rubber layer is thin, the reinforcing layer tends to be worn and the durability of the hose tends to decrease.If the thickness is large, the braid diameter increases, and as a result, the pressure resistance decreases and the cost increases. Tend to be.

After the innermost layer 2 is extrusion-molded, the intermediate resin layer 3 is extruded, and the inner tube outer layer rubber layer 4 is extruded and covered. Then, the fiber reinforcing layer 5 and the outer surface rubber layer 6 are laminated by braiding or spiral winding. I do. As the fiber reinforcing layer 5 and the outer rubber layer 6, conventional ones can be used as they are.

As the fiber reinforcing layer 5, for example, natural fibers, synthetic fibers such as polyvinyl alcohol-based, polyamide-based, polyester-based or aramid-based fibers can be used alone or as R.
FL-treated (resorcin-formaldehyde-latex adhesive). It is preferable that the thickness of the fiber reinforcing layer 5 be about 0.3 to 1.5 mm. If the amount of the fiber reinforcement layer is small, the pressure resistance tends to decrease, and if the amount is large, the cost increases and the efficiency of the reinforcement tends to decrease, thereby causing waste.

As the outer rubber layer 6, for example, EPD
Synthetic rubber excellent in ozone resistance, such as M, CR, CSM, IIR, X-IIR, and the like. The thickness of the outer rubber layer 6 is preferably about 1.0 to 2.0 mm. When the thickness of the outer rubber layer 6 is small, moisture easily penetrates into the hose, and the air conditioner tends to be poorly cooled. When the thickness is large, the cost increases and the flexibility tends to deteriorate.

In the composite flexible hose 1 of the present invention, the intermediate resin layer 3, the inner tube outer layer rubber layer 4, the fiber reinforcement layer 5, and the outer surface rubber layer 6 are laminated on the innermost layer 2, and then the whole is vulcanized by heating. Obtained by: Vulcanization conditions are about 150 ~
It is preferable to carry out vulcanization by heating at 180 ° C. by applying a vapor pressure.

The composite flexible hose 1 of the present invention obtained after vulcanization has sufficient flexibility and does not cause delamination even when a negative pressure is generated.

[0039]

EXAMPLES Hereinafter, the present invention will be described with reference to examples, but it is needless to say that the present invention is not limited to the examples.

The characteristics in each of the examples were measured by the following methods.

Material test of innermost layer (adhesion test between innermost layer and intermediate resin layer, 180-degree peel test (JIS K 6330-6 type 5)) The rubber composition for the innermost layer was 0.15 mm thick and about 30 mm wide. Length about 10
Cut to 0 mm, put a modified polyamide unvulcanized dough (2.0 mm thick, 200 mm square) for the intermediate resin layer, press-vulcanize it at 160 ° C. for 60 minutes, leave it at room temperature for one day, and width about 10 mm A test piece having a length of about 100 m was cut out. As the modified polyamide, a modified polyamide obtained by blending 40 parts by weight of an ionomer resin (olefin-acrylic acid-based copolymer) as a carboxyl group-containing modified polyolefin with respect to 60 parts by weight of polyamide-6 as a polyamide was used. .

This sample piece was subjected to a tensile tester (JIS B7
721), fixing the intermediate resin layer side, pulling the innermost layer side at a speed of 50 mm per minute as shown in FIG. 3, examining the peeling state at the bonding interface, and examining the cohesive failure of rubber (innermost layer). ○, resin (intermediate resin layer) and rubber (innermost layer) interface peeling (state where no rubber is attached to the resin) was x, and other states were Δ.

Hose Performance (Adhesion) A 25 mm wide and 100 mm long piece was cut out of the composite flexible hose 1 thus prepared, and the outer rubber layer 6 was cut out.
And the sample prepared by removing the fiber reinforcement layer 5,
The test piece was attached to a tensile tester (JIS B 7721) in the same manner as in the material test conditions for the innermost layer 2, and the intermediate resin layer 3
Side, the innermost layer 2 side is 50 m / min as shown in FIG.
The resin was pulled at a speed of m, and the peeling state at the bonding interface was examined. The rubber-cohesion-failure state was rated as ○, the resin-rubber interface peeling (without rubber on the resin) was rated X, and the other states were rated as Δ. .

Examples 1-4 The basic resin mixture A shown in Table 1 was replaced with an epoxy resin (Epicoat 828), a phenol resin (Sumikanol 620, manufactured by Sumitomo Chemical) and methylolmelamine (Sumikanol 507A, manufactured by Sumitomo Chemical) shown in Table 2. Was compounded and kneaded to prepare a rubber composition for the innermost layer 2.

Comparative Example 1 A rubber composition for the innermost layer 2 was prepared without adding an epoxy resin or a phenol resin as an adhesion improving component and methylolmelamine to the basic blended dough A shown in Table 1.

The properties (normal physical properties) of the obtained rubber dough were examined. Table 2 shows the results.

The adhesive strength between the intermediate resin layer 3 and the innermost layer 2 was examined using Zytel ST811Hs as the resin for the intermediate resin layer 3. Table 2 shows the results.

[0048]

[Table 1]

[0049]

[Table 2]

Using the rubber compositions for the innermost layer 2 prepared in Examples 1 to 4 and Comparative Examples 1 and 2, a composite flexible hose 1 was produced in the following manner, and the hose performance was examined.
Table 3 shows the results.

(Preparation of Composite Flexible Hose) A rubber mandrel (outer diameter: 15.75 m) was used for the innermost layer rubber composition.
m) and extruded to a thickness of 0.8 mm to form the innermost layer 2
And a modified polyamide for an intermediate resin layer is extruded thereon so as to have a thickness of 0.15 mm to form an intermediate resin layer 2. Then, a rubber composition having the same composition as the innermost layer 2 is coated with an inner tube outer layer rubber layer. After extruding and coating to a thickness of 0.8 mm as 4 and then braiding with polyethylene terephthalate yarn to form a fiber reinforcing layer 5, and finally EPDM with a thickness of 1.5 mm
The outer rubber layer 6 was formed by extrusion. The unvulcanized hose was vulcanized under the vulcanization conditions of 160 ° C. for 60 minutes to produce a composite flexible hose 1.

The bonded state of the obtained composite flexible hose 1 was examined. Table 3 shows the results.

[0053]

[Table 3]

[0054]

According to the present invention, in an inner tube three-layer hose in which a chloroprene rubber is provided on the innermost layer and a polyamide resin is provided on the outer side thereof and a rubber layer is provided on the outer side thereof, the innermost layer of the chloroprene rubber is provided. By mixing epoxy resin, phenol resin and methylol melamine, which are components for improving adhesive strength, stable and strong adhesion can be obtained without providing an adhesive layer between the polyamide resin of the barrier layer and R12. , R134a refrigerant, and a hose having a structure that significantly reduces gas permeation was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an outline of a laminated structure of an embodiment of a composite flexible hose of the present invention.

FIG. 2 is a schematic view showing an outline of a laminated structure of a conventional composite flexible hose.

FIG. 3 is a schematic diagram showing an outline of an adhesion test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Composite flexible hose 2 Innermost layer 3 Intermediate resin layer 4 Inner tube outer layer rubber layer 5 Fiber reinforcement layer 6 Outer surface rubber layer 7 Adhesive layer 8 Intermediate rubber layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08G 59/62 C08G 59/62 C08K 3/34 C08K 3/34 C08L 11/00 C08L 11/00 63/00 63/00 ACF term (reference) 3H111 AA02 BA12 BA15 BA34 CB06 CB14 DA26 DB09 DB19 DB25 4F100 AA03A AA03H AK03B AK28A AK28C AK33A AK46B AK47B AK48B AK53A AL05A AL05B AL07BBA00 BA02BA02 BA02 BA00 4J002 AC091 CC043 CC184 CD002 DJ006 GF00 4J036 AA01 AD08 AF06 AJ08 DA04 DC25 FB07 JA08

Claims (2)

[Claims] 1. An innermost layer, an intermediate resin layer, an inner tube outer layer rubber layer, a fiber reinforcing layer, and an outer rubber layer are laminated in this order from the inside, and the innermost layer is made of silicic acid or 100 parts by weight of chloroprene rubber. A rubber composition comprising 10 to 50 parts by weight of a salt thereof, 5 to 20 parts by weight of an epoxy resin, 0.5 to 5 parts by weight of a phenol resin and 0.5 to 5 parts by weight of methylolmelamine. The resin layer is made of a modified polyamide obtained by blending a polyamide and a carboxyl group-containing modified polyolefin, the inner tube outer layer rubber layer is made of a chloroprene-based rubber, and the innermost layer and the intermediate resin layer obtained by heating after laminating each of the above layers A composite flexible hose that does not have an adhesive between the inner and outer rubber layers. 2. The polyamide in the modified polyamide is selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 4-6, polyamide 6-6, polyamide 6-10, polyamide 6-12 and polyamide MXD-6. 2. The composite flexible hose according to claim 1, wherein the composite flexible hose is a polyamide made of a polyamide or a copolymer containing at least two kinds of constituent components.