JPH01259944A - Multilayer hose - Google Patents

Abstract

PURPOSE:To obtain a multilayer hose having bendability and excellent gas barrier properties by using gas barrier substance having high elasticity as a discontinuous layer, and multilayer laminating through a low elastic material layer. CONSTITUTION:A hose passage 1 is formed of an inner layer 2, and a gas barrier composite layer 5 is provided inside a reinforcing layer 3 and an outer layer 4. In the layer 5, ringlike or tapelike high elasticity gas barrier substance A layers 52, 54 are disposed to be laminated, a low elasticity substance B layer 3 is disposed between the layers 52 and 54, and the layer (close contact layer) 53 is so interposed in close contact between the layers 52 and 53 as to cover a problem of the bending hardness of the high elasticity gas barrier substance layer. In order to impart the excellent bendability and gas barrier properties, it is important to satisfy a following formula, EA/EB>=2 (wherein EA: the elastic ity kg/cm<2> of the substance A, EB: the elasticity kg/cm<2> of the substance B, the elasticity is of a value measured by ASTMD-638 (23 deg.C, 65%RH)).

Description

[Detailed Description of the Invention] A. Wano The present invention relates to a flexible multilayer hose with excellent gas barrier performance, good flexibility and pressure resistance, and is suitable for piping of various gas bodies or gaseous liquids. , is extremely useful.

B. Prior art Traditionally, flexible resin hoses, typically rubber hoses, are made of rubber or elastomer resin, and when reinforcing materials with high strength and high modulus of elasticity are used, they are made into thread-like, braided, or cross-like materials. It is flexible and flexible because it is constructed so as not to lose its flexibility.

In recent years, there has been a growing demand for such conductive hoses to have gas barrier performance against various gases such as freon. However, as expected to some extent from the basic properties of the resin, polyamide, vinylidene chloride resin (P), which is known as a barrier resin,
VDC), ethylene-vinyl alcohol copolymer (E
Compared to the soft resins such as rubber and elastomers conventionally used in hoses, VOH) etc. often have extremely high elastic modulus, that is, they are hard, and when used in a multilayer structure as part of the hose layer, Forcibly bending, long-term bending deformation, or repeated bending may cause the barrier layer and the adjacent layer to separate, or the barrier layer may buckle, collapse, or crack. There is a limit. Therefore, a soft and thin barrier layer with a relatively low barrier must be used, and it has been difficult to obtain a high barrier hose with good flexibility.

The object of the present invention is to provide a hose that is flexible and can maintain a high level of gas barrier properties even when a hard resin with gas barrier properties is used.

The present invention provides a multilayer hose having a gas barrier composite layer on the outer periphery of an inner tube, and further having a reinforcing layer as required on the outer periphery of the composite layer, wherein the composite layer has gas barrier properties. A multilayer hose in which layers of substance (A) are arranged so as to overlap, and a layer of low elasticity substance (B) satisfying the following formula (I) is further interposed between the layers of gas barrier substance (A). It is.

E A / E B ≧ 2 (I) EA:
Elastic modulus of substance A (23°C, 65% RH) EII: substance B
Elastic modulus (23°C, 65% RH) E, Brief explanation The present invention is a gas barrier material with a high elastic modulus! (A) is used as a discontinuous layer and the low elasticity material (B) layer is replaced by material (A).
The object of the present invention is to obtain a multilayer hose having flexibility and excellent gas barrier properties by interposing the layers and laminating them in duplicate.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Figure 9 shows a cross section of a typical conventional flexible multilayer hose (
(Longitudinal direction) view. The inner layer (inner tube) 2 forms a hose flow path space 1, and the outer side of the inner layer 2 is a reinforcing layer 3.
, an outer layer 4. Each layer 2.3.4 may be a further layer. Since the reinforcing layer 3 is usually made of filamentous material in the form of a net, a braid, a cloth, etc., the flexibility of the hose can be maintained even if the filamentous material is highly elastic. Moreover, the inner layer 2 and the outer layer 4 are usually rubber layers in many cases. The gas barrier properties of conventional such hoses are not very high, and in the case of gases with large molecular weights, for example, Freon gas Freon-12, conventional rubber hoses can be used as cooler hoses, but Freon-22 does not allow gas leakage. This increases and makes it difficult to use.

In order to solve the problem of the conventional gas barrier shortage, hoses using a gas barrier resin layer have begun to be developed.

FIG. 10 is a cross-sectional view of a conventional gas barrier hose. The hose configuration is similar to that shown in Figure 9, but the inner layer 2
Instead of a rubber layer, a gas barrier tube was used as the inner tube. In a hose that uses a gas barrier resin layer tube for the inner layer, since the gas barrier resin has a high elastic modulus, the inner layer tube 2 is hard and the entire hose is hard, which reduces workability on the hose piping and makes it difficult to use. The disadvantage is that vibration absorption is poor.

FIG. 11 is also a perspective view of a conventional multilayer hose with improved gas barrier properties. A reinforcing layer 3 and an outer layer (rubber N) 4 are used in a structure in which a gas barrier film tape 5 is laminated and wrapped around an inner tube 2; There is a problem in that a gap is formed between the parts, and if the material is bent too much, it may become misaligned or the gap increases, and repeated vibrations and bending may cause the gas barrier properties to deteriorate. This was particularly a problem when a film with high gas barrier properties was used.

As a result of studying the problem of such barrier tapes, the present inventor found that the cause of the problem is that gas barrier tapes are highly elastic and have no stretchability. It has been found that this problem can be solved by interposing an adhesion layer of 100% or less.

FIG. 1 is a cross-sectional view of a multilayer hose showing an example of the present invention. A hose flow path 1 is formed by the inner layer N2, and a gas barrier composite layer 5 is provided inside the reinforcing layer 3 and the outer layer 4. The inner layer 2 is preferably a rubber layer or a particularly low-modulus resin layer from the viewpoint of flexibility of the hose, but if barrier properties are important, an intermediate layer such as nylon 12, 6.66 copolymer nylon, nylon 11, or nylon elastomer may be used. Gas barrier resins with a low modulus of elasticity are also suitably applied. As with conventional hoses, the reinforcing layer 3 is mainly made of various fibrous materials.
If the pressure is not particularly high and the strength of the composite layer is sufficient, a structure without a reinforcing layer can be similarly applied, and the effects of the present invention will be the same. Next, the gas barrier composite layer 5, which is the most characteristic feature of the present invention, has a ring shape or a tape shape.
Gas barrier material (A) layers 52 and 54 having a high elastic modulus are arranged so as to overlap each other, and a material (B) layer 53 having a low elastic modulus is arranged between the layers 52 and 54.

Here, the gas barrier material (A) layers are arranged so as to overlap, which means that a tape-like material made of the gas barrier material (A) is wrapped around the inner tube 2, or a ring-like material is overlapped with each other. It means that the layer of the low elastic modulus material (B) is interposed between the layers of the gas barrier material (A), and the layer is interposed between the layers of the gas barrier material (A). (A) means that the substance (B) is arranged in at least a part of the overlap between the layers, specifically, for example, a laminated layer consisting of a gas barrier substance (A) layer and a low elasticity substance (B) layer. The purpose is achieved by wrapping a tape-like material around the inner tube 2.

FIG. 2 is an enlarged sectional view of the composite layer 5 of FIG.

Reference numeral 51 is an adhesion or adhesion layer to the inner layer, but this layer is not always necessary, and another intermediate layer may be provided in its place. The A layers 52 and 54 may be made of the same material or may be made of different high modulus gas barrier materials. The low elasticity material layer (adhesion layer) 53, which is the most characteristic feature of the present invention, is provided between 52 and 53 in close contact with each other in order to overcome the problem of bending hardness of the high elasticity gas barrier material layer. It is being Although the gas barrier layer is arranged discontinuously in the longitudinal direction, this (B) layer is preferably present in at least the overlapped portion, so that the gas barrier layer maintains some elasticity and is - Can also improve performance. Reference numeral 55 is an adhesive or adhesion layer to the outer layer, but this layer is not always necessary, and other intermediate layers may be provided in its place.

Further, FIG. 3 shows a cross-sectional view of a hose according to another example of the present invention. As in FIG. 1, the inner layer 2 of the hose forms a hose flow path 1, and a gas barrier composite layer 5 is provided inside a reinforcing layer 3 and an outer layer 4. The composite layer 5 has a structure in which a low elastic modulus layer 53 is interposed between gas barrier tape-like materials 52 and 54, and is a laminated layer of the tape-like material 52 and a low-modulus tape-like material, and is a layer of the inner tube 2. Obtained by wrapping around.

FIG. 4 is an enlarged cross-sectional view of the composite layer 5 of FIG. Fourth
The configuration of the illustrated example is basically the same as that of FIG. 2.

In the present invention, in order to provide excellent flexibility and gas barrier properties, it is important to satisfy the following formula (1).

EA/EB≧2 (■) EA: Elastic modulus of material A kg/cm" E,: Elastic modulus of material B kg/ca" This elastic modulus is based on ASTM D-638 (23°C, 65°C)
%RH).

More preferably, the following conditions are satisfied.

SOO≧ E A / E s≧ 3 ... (
I)'Normally, the EA of substance A is 6,000 to 50,000 kg
/am'', preferably from 8,000 to 40,000, and the Ee of substance B is preferably less than 8,000 kg/am'', preferably less than 6,000, but the material used and construction configuration may vary depending on the usage conditions and size of the final hose. is selected.

Further, it is preferable that the material A layer and the material B layer satisfy the following conditions (II) to (V).

4000≧LA/TA≧20...
(If)ΔL/LA≧0,2... (I[[)
T B / T A ≧ 0.7 ... (■) ΔL
/ T +s≧10... (V) LA: Width of material A layer TA: Thickness of material A layer TB: Thickness of material B layer ΔL: Length of multiple parts of material A layer More preferably, the following conditions are met. It is good to satisfy the following.

2500≧ LA / T＾≧ 50... (
■)′ΔL/LA≧0.3... (■)
'T♂/TA≧1,2... (■)'ΔL/
T e≧20... (■)' Also, when the diameter of the composite layer 5 is about 5 to 30 mm, LA is 4 to 40+aa+,
TA is 3 to 250μ, more preferably 5 to 100μ, ΔL is 2 to 30mm, and TB is selected from the range of 5μ to 1000μ.

Examples of substance A include ethylene-vinyl alcohol copolymer, vinylidene chloride resin, gas barrier polyamide resin, gas barrier polyethylene terephthalate, and other polyester resins, but alloys of various resins, metal powder, and inorganic Those to which a modifier such as a filler is added are also preferably used. Moreover, surface-coated materials, metal vapor-deposited materials, and laminated sheet materials are also suitably used.

Further, as the ethylene-vinyl alcohol copolymer, a saponified ethylene-vinyl acetate copolymer having an ethylene content of 125 to 55 mol% and a degree of saponification of the vinyl acetate component of 90 mol% or more, preferably 95 mol% or more is suitable. used for.

The tape-like material of substance A can be obtained, for example, by extruding substance A into a film, stretching it, and subjecting it to heat treatment if necessary.

Substance B includes various soft resins, copolymer soft resins, various elastomers (e.g. polyamide elastomer, polyester elastomer, polyurethane elastomer, polystyrene elastomer, rubber elastomer), adhesive resins (e.g. polyester adhesive resin, polyolefin adhesive resin, Examples include polyamide adhesive resins and blends thereof, but there are no particular limitations as long as the resin exhibits a low elastic modulus of less than 8,000.

In addition, when used in Freon gas hoses for automobile coolers, Substance B is required to have heat resistance and pressure resistance, so Substance B with a melting point of 100°C or higher, preferably 120°C or higher is used.
is preferably used.

Further, the tape-shaped material of substance B can be obtained by, for example, extrusion film-forming of substance B, or further stretching and, if necessary, heat treatment. The tape-like substance B may be adhered to the tape-like substance A by self-melting or an adhesive, but it is also possible to just make them adhere to each other in a non-adhesive manner. Particularly when flexibility is important, non-adhesion is effective.

In the present invention, it is best to use a tape-shaped article of substance A and a tape-shaped article of substance B that are closely attached or glued together. Alternatively, a material coated with substance B by coextrusion film formation, extrusion coating, or solution coating can also be used.

Next, other aspects of the present invention will be explained. Figures 5 to 8
The figure is a cross-sectional view of the composite layer 5 corresponding to FIG. 4.

FIG. 5 shows a composite tape in which a tape 53 of substance B is attached to at least one side of a tape 54 of substance A. Using this composite tape is convenient because only one tape winding process is required. It is.

FIG. 6 shows an example of multi-layering material A, which is a laminated structure in which a layer 54 of material A is provided in the middle of the tape, and other material layers 56, such as flexible layers, are provided in the inner and outer layers. This structure not only strengthens the material A layer, but also
Functionality is also improved.

Figure 7 shows a tape-like material of material B with a reinforcing layer or a heat-resistant F material.
J57 is laminated to improve the tape functionality of the material layer.

FIG. 8 shows two layers of material A layer 54 and material B layer 53, respectively.
This layer is made into a tape-like material and wrapped around a hose to form a composite layer. The lamination overlap part of the adhesive layer consists of two parts, ΔL part and ΔL' part, and ΔL' part is glued,
The ΔL portion (the portion to which the tape-like material is in close contact) may be bonded or may be non-bonded.

The multilayer hose of the present invention is used for various gas hoses such as air conditioner hoses, especially automobile air conditioner hoses, propane gas hoses, medical hoses, hot water circulation heating hoses, etc., and in particular, Freon 12, Freon 22, Ol, C
Suitable for use as a barrier hose for O, Nt gas.

Although the present invention has been explained with reference to the drawings, in reality, the inner layer (inner tube) 2 is made of rubber (hardness 76 according to JIs-A; thickness 2 to 3 mm), and the reinforcing layer 3 is made of polyethylene terephthalate fiber braid ( 1mm thick), outer layer 4
Rubber (hardness 70 according to JIS-A; thickness 1.5
mm), and the gas barrier material layer 52 of the gas barrier composite layer 5 is an ethylene-vinyl alcohol copolymer with an ethylene content of 32 mol% (elastic modulus E A = 210
00kg/cm", thickness 15μ, width 20o+m, length of the overlapping part of this layer 10μm) as the low elastic material layer 53, a copolymerized nylon 6 elastomer (modulus of elasticity E8 = 200
0 kg/am'; thickness 30 μm) were used.

In addition, after the multilayer hose obtained in this way was subjected to a bending test 3000 times, Freon R-22 (fluorocarbon) was added to the multilayer hose (5 pieces).
Gas leakage was measured at 45℃ and pressure 15kg/am''.As a result, 1 out of 5 hoses showed an increase in gas leakage of 50% or more compared to the gas leakage of the multilayer hose before the bending test.
There were no books either. Also, a gas barrier without a layer of low elasticity material.
Similar gas leakage measurements were conducted for the multilayer hoses (5 pieces) that had only a layer of resistant material, but in 4 out of 5 cases, the gas leakage increased by 50% or more compared to the multilayer hoses before the bending test. Ta.

Although not shown in the drawings, it is possible to provide various layers between the layers constituting the multilayer vibe, for example, to provide an intermediate layer such as a rubber layer between the gas barrier composite layer 5 and the reinforcement layer 3 as necessary. Be free.

L-11911 The multilayer hose of the present invention has excellent bending resistance and gas barrier properties, and is suitable for use in cooler hoses, especially automobile cooler hoses, propane gas hoses, various gas hoses, hot water circulation heating hoses, etc. Suitably used.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view (longitudinal direction) of the layers of the multilayer hose of the present invention, and FIG. 2 is a composite I! of FIG. 15 is an enlarged cross-sectional view of FIG. FIG. 3 is a cross-sectional view (longitudinal direction) of the layers of a multilayer hose according to another example of the present invention, and FIG. 4 is an enlarged cross-sectional view of the composite layer 5 of FIG. 3. 5-8 are enlarged cross-sectional views of a composite layer 5 of layers of a multilayer hose according to another example of the present invention. 9-10 are cross-sectional views of the layers of a conventional multilayer hose, and FIG. 11 is a perspective view of the conventional multilayer hose. l... Hose flow path space 2... Inner layer (inner tube) 3... Reinforcement layer 4... Outer layer 5... Gas barrier composite layer 52... Gas barrier material layer 53. ...Low elasticity material layer 54...Gas barrier material layer Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6

Claims (3)

[Claims] (1) In a multilayer hose having a gas barrier composite layer on the outer periphery of the inner tube, the composite layer is arranged such that the layers of the gas barrier material (A) overlap, and the gas barrier material (A) Between the layers of (I)
A multilayer hose in which a layer of a low elastic material (B) that satisfies the formula is interposed. E_A/E_B≧2...(I) E_A: Elastic modulus of material A (23°C, 65% RH) E_B: Elastic modulus of material B (23°C, 65% RH) (2) The multilayer hose according to claim 1, further comprising a reinforcing layer around the outer periphery of the gas barrier composite layer. (3) The multilayer hose according to claim 1 or 2, which satisfies the following formulas (II) to (V). 4000≧L_A/T_A≧20...(II) ΔL/L_A≧0.2...(III) T_B/T_A≧0.7...(IV) ΔL/T_B≧10...(V) L_A: Width of material A layer T_A: Thickness of material A layer T_B: Thickness of material B layer ΔL: Length of overlap between material A layers