JPH06246887A - Hose for automotive fuel piping - Google Patents

Abstract

PURPOSE:To provide a low-cost hose for automotive fuel piping excellent in all resistance to permeation of gasoline, flexibility, resistance to kink, assembling workability and sealing properties. CONSTITUTION:The hose concerned for automotive fuel piping consists of an inner tube layer 2 and an outer tube layer 3 which is formed on the outer periphery of the inner tube layer 2. In addition, the inner tube layer 2 is composed of a resin composition mainly made of modified polyolefin (a) and polyamide resin (b) under the set mixing ratio a/b by weight of 70/30-10/90.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle fuel piping hose used for an evaporative hose, a breather hose, a fuel hose, etc. for connecting an automobile gasoline tank and an engine.

[0002]

2. Description of the Related Art A fuel pipe for an automobile is generally composed of a metal pipe and a hose connecting the metal pipes. Examples of such hoses include an evaporative hose connecting a gasoline tank to an engine, a breather hose used for an air bleeding portion of a gasoline tank, and a fuel hose connecting an engine to a gasoline tank. The hose comprises, for example, an inner tube rubber layer made of acrylonitrile-butadiene rubber (NBR), a reinforcing thread layer made of braided or spiral knitted polyester thread on the outer circumference of the inner tube rubber layer, and an outer circumference of the reinforcing thread layer. Outer rubber layer made of rubber elastic material. In the case of a fuel hose, chloroprene rubber (CR), epichlorohydrin rubber (CHC), chlorosulfonated polyethylene rubber (CSM), or the like is used as the rubber elastic material. Also,
As the evaporative hose and the breather hose, a mixture of NBR and polyvinyl chloride (PVC) is used for the inner rubber layer.

[0003]

With respect to these hoses, there is a phenomenon in which vaporized gasoline permeates the hoses and leaks to the outside. In recent years, in particular, the number of automobiles has been increasing, and environmental deterioration due to gasoline leaking from such hoses has become a serious problem. Therefore, it has been enacted to regulate the amount of vaporized gasoline that leaks from such automobiles. Especially, since 1994, in California, the United States, the permeation amount of unburned evaporated gasoline from evaporative hoses is strictly regulated. This is about 1/1 of the conventional gasoline permeation amount
It is regulated to 0 or less. Further, since the fuel consumption standard line has been regulated more severely since 1996, weight reduction is demanded from the viewpoint of improving fuel consumption. for these reasons,
A hose has been proposed in which fluororesin (FKM) is used instead of NBR, which is the material for forming the inner tube rubber layer. The hose made of this FKM can suppress the amount of vaporized gasoline permeated, but the cost is high because the FKM is expensive. Therefore, an alternative to the FKM having excellent gasoline permeation resistance is being investigated. But F
As for the alternative to KM, even if it has excellent gasoline permeation resistance, it has poor rigidity due to its high rigidity, poor kink resistance (buckling resistance), and assembly workability that is difficult to insert into metal pipes. And various sealing problems.

The present invention has been made in view of the above circumstances, and is a low-cost automobile fuel pipe hose excellent in gasoline permeation resistance, flexibility, kink resistance, assembling workability and sealing performance. The purpose is to provide.

[0005]

In order to achieve the above object, an automobile fuel piping hose according to the present invention comprises an inner tube layer composed of a single layer or multiple layers, and an outer tube formed on the outer periphery of the inner tube layer. A fuel hose for a vehicle having a layer,
At least one of the inner tube layers is formed of a resin composition containing the following component (A). (A) The following (a) and (b) are the main components, and the blending ratio (a / b) of the following modified polyolefin (a) and polyamide resin (b) is a / b = 70/30 by weight ratio. ~ 1
A resin composition set to 0/90. (A) Modified polyolefin. (B) Polyamide resin.

[0006]

That is, the inventors of the present invention have conducted a series of studies in order to obtain a hose for automobile fuel piping, which is excellent not only in gasoline permeation resistance but also in kink resistance, assembling workability and flexibility. As a result, when the inner tube layer is formed by the resin composition obtained by blending the modified polyolefin and the polyamide resin in a predetermined blending ratio, the inner tube layer formed by the resin composition has a gasoline resistant property due to the characteristics of the polyamide resin. It has excellent permeability, and because it contains a modified polyolefin, it is also highly flexible and has improved sealing properties. Along with this, the kink resistance of the entire hose is improved and the workability of assembling is also improved. Furthermore, they have found that the flexibility of the entire hose is improved and have reached the present invention.

Next, the present invention will be described in detail.

The hose for automobile fuel piping of the present invention is an inner tube layer (single layer or single layer formed by at least one layer of a resin composition (component A) containing a modified polyolefin (a) and a polyamide resin (b) as main components. (Multilayer structure) and an outer layer formed on the outer circumference of the inner tube layer. In the present invention, the term “main component” is intended to include a case where only the main component is included.

At least one of the inner pipe layers is obtained by using a resin composition (component A) containing a modified polyolefin (a) and a polyamide resin (b) as main components.

The modified polyolefin (a) is obtained by modifying a polyolefin such as a homopolymer of ethylene or propylene or a copolymer thereof by graft polymerization of a monomer such as an unsaturated carboxylic acid or its derivative. Examples of the unsaturated carboxylic acid used as the graft polymerization component include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, and unsaturated dicarboxylic acids such as maleic acid and fumaric acid. Examples of the unsaturated carboxylic acid derivative include acid anhydrides, amides, esters and acid halides. These may be used alone or in combination of two or more. And such a graft polymerization component will be used within the range of 0.1 to 20 mol% in the resulting graft polymer.

The polyamide resin (b) used with the modified polyolefin (a) is nylon 6,
Examples include nylon 66, nylon 12, nylon 612 and nylon 6/66. These may be used alone or in combination of two or more.

The blending ratio (a / b) of the modified polyolefin (a) and the polyamide resin (b) is a weight ratio of a
It is preferable to set the ratio of / b = 70/30 to 10/90. That is, when the blending ratio of the polyamide resin (b) exceeds 90 (the modified polyolefin is less than 10), the gasoline permeation resistance is extremely excellent, but the flexibility, kink resistance, assembling workability and sealability are poor, and the polyamide resin When (b) is less than 30 (modified polyolefin exceeds 70), flexibility, kink resistance, assembling workability and sealing performance are extremely excellent, but gasoline permeation resistance is poor.

In the resin composition (component A) of the present invention, in addition to the modified polyolefin (a) and the polyamide resin (b), it is widely used as a raw material monomer of nylon 6 for the purpose of plasticizing. It is preferable to incorporate ε-caprolactam. By blending this ε-caprolactam as a plasticizer, the resin composition can be softened, and the flexibility, kink resistance, assembling workability and sealing property of the obtained hose can be improved. Further, this ε-caprolactam can improve the adhesiveness to the outer rubber layer. The amount of ε-caprolactam is preferably set to a ratio of 1 to 15% by weight based on the entire resin composition (component A).
That is, if the blending amount of ε-caprolactam exceeds 15% by weight, the gasoline permeation resistance of the obtained hose tends to deteriorate.

In addition to the modified polyolefin (a), the polyamide resin (b) and ε-caprolactam, various additives such as an antioxidant and a processing aid may be added to the resin composition (component A), if necessary. The agent can be appropriately mixed.

The outer layer is formed by using a rubber elastic material. Examples of the rubber elastic material include CR, CSM, a mixture of NBR and PVC, CHC, ethylene-propylene-diene rubber (EPDM), chlorinated polyethylene rubber (CP).
E), acrylic rubber (ACM) and the like.

The automobile fuel piping hose of the present invention is manufactured, for example, as follows. That is, first, a modified polyolefin (a), a polyamide resin (b), a plasticizer and various additives are blended and uniformly mixed to prepare a resin composition (component A) which is an inner tube layer forming material. Then, it can be manufactured by sequentially laminating according to the following items.

Resin Composition for Forming Inner Tube Layer (Component A)
Is extruded by an extruder to form a tubular body. When the inner tube layer is a multi-layer, at least one layer is extruded by the above-mentioned extrusion operation using the component A, and other forming materials are repeated a plurality of times depending on the layer constitution, or the multi-layer is co-extruded. An inner tube layer consisting of multiple layers is obtained. In addition, in such a plurality of times of extrusion molding, an adhesive treatment may be appropriately performed between the layers of the inner pipe layer composed of a plurality of layers.

Next, an adhesive (rubber glue or the like) is applied to the outer peripheral surface of the inner tube layer composed of the above-mentioned single layer or multiple layers, if necessary, and then the outer tube layer is formed with a rubber composition for forming an outer tube layer. The product is extruded by an extruder to obtain a desired outer tube layer.

The laminated fuel tube thus obtained is heated and vulcanized at a predetermined temperature to be integrated, whereby a target hose for automobile fuel piping can be manufactured. The vulcanization conditions at this time are usually 150 to 160.
A vulcanization time of about 30 to 60 minutes at a temperature of about ° C can be mentioned.

The automobile fuel pipe hose thus obtained is shown in FIGS. 1 and 2. In this automobile fuel piping hose, the inner tube layer 2 has a single-layer structure, and the outer tube rubber layer 3 is integrally formed on the outer circumference of the inner tube layer 2.

In the above fuel hose for automobiles, a fiber reinforcing layer 4 may be provided between the inner tube layer 2 and the outer tube rubber layer 3 as shown in FIGS. As the fiber reinforcing layer 4, the one used for a normal rubber hose is adopted as it is, and is formed by, for example, braid knitting or spiral knitting of a thread mainly composed of synthetic fiber such as polyester fiber or aramid fiber.

FIG. 5 shows another embodiment of the automobile fuel piping hose of the present invention. This automobile fuel piping hose is composed of a resin layer 5 in which the inner tube layer 2a is the innermost layer and an inner tube resin layer 6 made of a resin material. And
An outer rubber layer 3 is formed on the outer circumference of the inner resin layer 6. In this hose, the inner pipe resin layer 6 is formed of the resin composition (component A). The outer tube rubber layer 3 may be formed of, for example, CR, CSM, N
In addition to a mixture of BR and PVC, CHC, etc., a rubber material (non-polar rubber material) having no polar functional group such as ethylene-propylene rubber (EPM) and EPDM can be used. That is, when ε-caprolactam is blended in the component A, which is the material for forming the inner tube resin layer 6, the affinity between the ε-caprolactam and the nonpolar rubber material other than the rubber having a polar functional group. Is good, the adhesiveness between the inner pipe resin layer 6 and the outer pipe rubber layer 3 is improved. In addition,
An adhesive treatment is appropriately applied between the inner tube resin layer 6 and the outer tube rubber layer 3 so as to integrate these two layers.
As this adhesive, a chlorinated rubber-based adhesive, a phenol-based adhesive or the like is preferably used.

In the fuel pipe hose for automobiles of the present invention, its layer structure is appropriately selected according to its application, and thereby it is possible to obtain a predetermined effect associated with each layer structure.

In the automobile fuel piping hose of the present invention, the thickness of each layer is appropriately set according to the type of material forming them and the thickness of the hose. For example,
If the inner diameter of the hose is 1, the inner tube layer 2,
The thickness of 2a is preferably set to 1/30 or more,
The outer tube layer 3 preferably has a thickness of 1/6 or more. Specifically, the inner diameter of the hose 1 is 3.0 to 15.0 m.
In the case of m, the thickness of the inner tube layers 2 and 2a is 0.1 to 1.5 mm.
The outer tube layer 3 preferably has a thickness of 1.5 to 4.0 mm.
Particularly preferably, the inner tube layers 2 and 2a have a thickness of 0.3 to 0.
The outer tube layer 3 has a thickness of 5 to 5 mm and a thickness of 2.7 to 2.9 mm.
When the inner pipe layer 2a has a multilayer structure as shown in FIG. 5, the innermost resin layer 5 has a thickness of 0.1 to 0.5 m.
m, and the thickness of the inner tube resin layer 6 is preferably set to 0.1 to 1.5 mm.

Further, in the automotive fuel piping hose of the present invention, the bending elasticity of the inner pipe layer 2 (in the case of a single layer structure) or the resin layer 2a (in the case of a multilayer structure) made of a specific resin composition (component A). Rate 1000-5000kgf / c
It is preferable to set it in the range of m ² . Particularly preferably, it is 1000 to 4000 kgf / cm ² . The hardness of the outer layer 3 made of a rubber elastic material is preferably set to 45 to 75 (Hs), particularly preferably 60 to 70 (Hs).
s). By setting the characteristics of each layer as described above, it is possible to obtain a hose having excellent kink resistance, flexibility, airtightness, assembling workability (insertability into a metal pipe), and the like.

The hose for automobile fuel piping thus obtained has, for example, a hose having a single-layer inner tube layer (see FIGS. 1 and 2), as shown in FIG. It is fitted and used for fuel piping.

[0027]

INDUSTRIAL APPLICABILITY As described above, the automotive fuel pipe hose of the present invention comprises the resin composition (component A) containing the modified polyolefin (a) and the polyamide resin (b) as the main components, which are compounded in a predetermined compounding ratio. The outer tube layer is formed on the outer peripheral surface of the inner tube layer formed by (1). For this reason, the inner tube layer is rich in flexibility while having excellent gasoline permeation resistance due to its forming material, and moreover, has kink resistance, sealability, and
Excellent workability and pressure resistance. And the flexibility of the whole hose is also rich. Therefore, the automobile fuel pipe hose of the present invention is most suitable for, for example, an evaporative hose, a breather hose, a fuel hose or the like that connects an automobile gasoline tank and an engine, and has a very high utility value.

Next, examples will be described together with comparative examples.

First, a polyamide resin elastomer was prepared prior to the examples. [Preparation of Resin Composition] Modified polyolefins and polyamide resins shown in Tables 1 and 2 below and various additives were blended and mixed in the proportions shown in the same table to prepare resin compositions. In Tables 1 and 2 below, P
A6 is nylon 6.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

Examples 1 to 8 and Comparative Examples 1 to 5 Using the raw materials shown in Tables 3 to 6 below, hoses for automobile fuel pipes were obtained according to the above-mentioned manufacturing method. The thickness and flexural modulus of the inner layer, the thickness and hardness (JIS hardness) of the outer layer, and the inner diameter of the hose are also shown in Tables 3 to 6 below. The vulcanization conditions are
It was set at 150 ° C. for 35 minutes. Also, C in Tables 3 to 6
R is chloroprene rubber. Then, the bending elastic modulus of the inner layer was measured as follows. That is, based on the three-point bending test method in the plastic bending test method, a predetermined size (length: 80 ± 5 mm, width: 10
The test piece was molded into ± 0.5 mm and thickness: 4 ± 0.2 mm. Then, using the device shown in FIG.
The test piece 7 was bridged over the pressure wedge 5, and the pressure wedge 5 was lowered from the center at a constant speed (30 mm / min). The load-deflection curve at this time was recorded on a chart paper, and the bending elastic modulus was calculated by the following formula.

E = L ³ / (4 × bh ³ ) × (F / Y) The meaning of each symbol in the above formula is shown below. E: Flexural modulus (kgf / cm ² ) L: Distance between fulcrums (cm) b: Width of test piece (cm) h: Thickness of test piece (cm) F: Arbitrary linear portion at the beginning of load-deflection curve Load at selected point (kgf) Y: Deflection amount at load F (cm)

[0034]

[Table 3]

[0035]

[Table 4]

[0036]

[Table 5]

[0037]

[Table 6]

[0038]

Comparative Example 4 A hose for automobile fuel piping having a single-layer structure made of a polyamide resin containing a plasticizer was produced.

[0039]

COMPARATIVE EXAMPLE 5 An inner layer tubular body was extruded using NBR,
Then, a reinforcing yarn layer was formed on the outer periphery of the inner layer tubular body by braiding a polyester yarn. Then, the outer layer was extrusion-molded on the outer periphery of the reinforcing yarn layer by using CR. Thus, a hose for automobile fuel piping was manufactured.

Each of the automobile fuel piping hoses obtained as described above was measured and evaluated for gasoline permeation resistance, kink resistance, flexibility, airtightness, assembling workability, and pressure resistance. Further, the flexural modulus of the inner layer of the automobile fuel piping hose which is an example product was measured. Then, from the above measurement results, each hose was comprehensively evaluated in three stages. That is, ◯ is excellent, Δ is normal, and X is poor. The results are shown in Tables 7 to 9 below. The evaluation of each of the above characteristics was performed according to the following methods.

[Gasoline permeation resistance] As shown in FIG.
A sample (hose) 10 cut into a specified length (free length of 500 mm) is provided with two pipes 13 and 1 of a fuel tank 12.
It was fitted in the No. 4 and fixed by the clamp 15. Then, the fuel tank 12 was filled with the sample fuel (specified gasoline) 11 up to 85% of the tank capacity, and the fuel 11 was brought into contact with the entire surface of the sample 10.
It was left for 8 hours. Then, after being left to stand, the sample 10 is removed from the fuel tank 12, and the fuel tank 1 shown in FIG.
Both ends of the sample 10 were fitted into two pipes 17 and 18 formed on the upper surface of the sample 6 and fixed by the clamp 15. Next, the fuel tank 16 was filled with about 100 cc of new specified gasoline 11, and the inside of the sample 10 was made into a gasoline vapor shape. Then, in this state, the total weight was measured every 24 hours in a constant temperature bath at 40 ° C. for 3 days. Then, the gasoline permeation amount was calculated by the following formula.

Θ = [Wn-W (n-1)] / S [In the above equation, Θ is the permeation amount per day (g / m ² / d)
ay), S is the area (m ² ) of the outer surface of the sample 500 mm,
Wn is the mass (g) of the sample set state after n days, and n
Is an integer of 0 to 3. ]

If it is less than 100 g / m ² / day, it is ○, if it is 100 to 300 g / m ² / day, it is Δ,
Those exceeding 300 g / m ² / day were indicated as x.

[Kink resistance] As shown in FIG. 10, a sample (hose) 19 having a length of 1 m was used to form a ring, and the crossing portion was held by hand, and the sample 19 was pulled in the direction of the arrow for 1 minute. Held After holding, the outer diameter D of the sample 19 in the R part
₁ (mm) was measured to determine the retention rate. Next, the diameter of the ring of the kneaded R portion was calculated by further reducing the diameter of the ring. The retention rate was calculated by the following formula.

Retention rate (%) = (D ₁ / D) × 100 [In the above formula, D is the outer diameter (mm) of the initial sample (hose). However, both D ₁ and D are short diameters of the outer diameter of the sample (hose). ]

Those kinked with R of less than 70R are indicated by ◯, those kinked with R in the range of 70R to 100R are indicated by Δ, and those kinked with R greater than 100R are indicated by X.

[Flexibility] A sample (hose) having a length of 150 mm was prepared and used in the plastic bending test method.
It measured based on the point bending test method. That is, FIG.
As shown in FIG. 2, the hose 21 is bridged over the two support bases 20 and the pressure wedge 22 is moved from the center of the hose 21 to 30 mm /
It was lowered at a speed of min, and the relationship between the displacement and the load at this time was measured.

When the displacement is 10 mm, the load is 1.
Less than 5 kgf / cm ² ○, 1.5-3.0 kg
Those with f / cm ² are shown as Δ, and those with more than 3.0 kgf / cm ² are shown as x.

[Airtightness] As shown in FIG.
Both ends of the 0 mm sample (hose) 23 were attached and fixed to the pipe portion 25 of the fixing jig 24. Then, air (or inert gas) is introduced into the hole at the end of the fixing jig 24 from the direction of the arrow.
Was fed to fill the hose 23 at a specified pressure and immersed in a water tank. Then, after the lapse of the specified time, the presence or absence of leakage of the pressurized gas was examined.

The specified pressure is 10 kgf / cm ²
Higher ones ○, of those ^{2~10kgf / cm 2 △, 2kgf /} cm 2 less than what is displayed as ×.

[Assembly Workability] As shown in FIG. 13, a sample (hose) 26 having a length of 50 mm was set upright and a pipe 28 attached to a compression tester 27 was set at a speed of 30 mm / min in the direction of the arrow. It was inserted into the hose 26. The maximum load during the insertion was measured.

If it is less than 15 kgf, it is ○, 15
△ for 30kgf, x for more than 30kgf
Displayed as.

[Pressure resistance] A hose having a length of 300 mm was attached to a burst tester, and a sample (hose) was filled with a pressurized liquid (water or oil). Then, 70kgf / min
The pressure at the time of bursting was measured by pressurizing at a pressurizing rate of cm ² .

[0054] and, more than 50kgf / cm ² is ○, those of 10~50kgf / cm ² △, 10kg
Those with a value of less than f / cm ² were marked with x.

[0055]

[Table 7]

[0056]

[Table 8]

[0057]

[Table 9]

From the results of Tables 7 to 9 above, the products of Examples are
It can be seen that while it has excellent gasoline permeation resistance, it also has excellent kink resistance, flexibility, airtightness, assembly workability, and pressure resistance.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a configuration of a vehicle fuel piping hose of the present invention.

FIG. 2 is a vertical cross-sectional view of the automobile fuel piping hose.

FIG. 3 is a perspective view showing another configuration of the automobile fuel piping hose of the present invention.

FIG. 4 is a vertical cross-sectional view of the automobile fuel piping hose.

FIG. 5 is a perspective view showing still another configuration of the automobile fuel piping hose of the present invention.

FIG. 6 is a cross-sectional explanatory view showing a usage state of the automobile fuel piping hose of the present invention.

FIG. 7 is an explanatory diagram showing a method for measuring a bending elastic modulus of a hose inner tube layer portion.

FIG. 8 is an explanatory diagram showing a method for measuring and evaluating gasoline permeation resistance of an automobile fuel piping hose.

FIG. 9 is an explanatory diagram showing a method of measuring and evaluating gasoline permeation resistance of an automobile fuel piping hose.

FIG. 10 is an explanatory diagram showing a method for measuring and evaluating kink resistance of an automobile fuel piping hose.

FIG. 11 is an explanatory diagram showing a method for measuring and evaluating flexibility of an automobile fuel piping hose.

FIG. 12 is an explanatory diagram showing a method for measuring and evaluating the airtightness of an automobile fuel piping hose.

FIG. 13 is an explanatory diagram showing a method for measuring and evaluating the workability of assembling an automobile fuel piping hose.

[Explanation of symbols]

 2 Inner tube layer 3 Outer tube rubber layer

Claims (4)

[Claims] 1. A fuel hose for an automobile, comprising a single-layered or multi-layered inner tube layer and an outer tube layer formed on the outer periphery of the inner tube layer, wherein at least one of the inner tube layers is A hose for automobile fuel piping, which is formed of a resin composition comprising the following component (A). (A) The following (a) and (b) are the main components, and the blending ratio (a / b) of the following modified polyolefin (a) and polyamide resin (b) is a / b = 70/30 by weight ratio. ~ 1
A resin composition set to 0/90. (A) Modified polyolefin. (B) Polyamide resin. 2. The outer tube layer is formed of a rubber elastic material,
And the thickness of the inner tube layer is 1/30 with the inner diameter of the hose as 1.
The thickness is set to the above, and the thickness of the outer tube layer is set to 1/6 or more with the inner diameter of the hose being 1.
Hose for automobile fuel piping described. 3. The resin composition comprising the component (A) contains ε-caprolactam as a plasticizer in an amount of 1 to 1 of the entire resin composition.
The hose for automobile fuel piping according to claim 1 or 2, wherein the hose is blended in a proportion of 0% by weight. 4. The inner pipe layer has a thickness of 1/30 to 1/4 with the inner diameter of the hose being 1 and the outer pipe layer has a thickness of 1/2 to 1 / with the inner diameter of the hose being 1. The hose for automobile fuel piping according to any one of claims 1 to 3, which is set to have a size of 6.