JP3166382B2 - Hose for automotive fuel piping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A fuel pipe of an automobile generally comprises a metal pipe and a hose connecting the metal pipes. Examples of such a hose include an evaporative hose connecting the gasoline tank to the engine, a breather hose used for the air vent portion of the gasoline tank, and a fuel hose connecting the engine to the gasoline tank. The hose includes, for example, an inner tube rubber layer made of acrylonitrile-butadiene rubber (NBR), a reinforcing yarn layer made of braided or spiral knitted polyester yarn around the inner tube rubber layer, and an outer periphery of the reinforcing yarn layer. And an outer tube rubber layer made of a rubber elastic material. As the 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. Also,
As the evaporation hose and the breather hose, a mixture of NBR and polyvinyl chloride (PVC) or the like is used for the inner tube rubber layer.

[0003]

As for these hoses, a phenomenon has occurred in which vaporized gasoline permeates through the hose and leaks to the outside. Recently, the number of automobiles has been particularly increasing, and the deterioration of the environment due to gasoline leaking from such hoses has become a major problem. Therefore, it has been enacted to regulate the amount of vaporized gasoline leaking from such automobiles. In particular, since 1994, in California, the United States, the amount of permeated unburned evaporated gasoline from evaporation hoses has been strictly regulated. That is, about 1/1 of the conventional gasoline permeation amount
It is regulated to 0 or less. In addition, the standard line for fuel economy has been more strictly regulated since 1996, and there is a demand for weight reduction from the viewpoint of improving fuel economy. because of these reasons,
A hose using a fluorine resin (FKM) instead of NBR, which is a material for forming the inner tube rubber layer, has been proposed. The hose made of this FKM can suppress the permeation amount of vaporized gasoline, but the cost is high because the FKM is expensive. Therefore, those having excellent gasoline permeation resistance in place of the above-mentioned FKM are being studied. But F
As for the alternative to KM, even if it has excellent gasoline permeability resistance, it has high rigidity, so it is inferior in flexibility, inferior in kink resistance (buckling resistance), and hard to insert into metal pipes. Inferior and poor sealing performance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a low-cost automobile fuel hose having excellent gasoline permeability, flexibility, kink resistance, assembling workability, and sealability. The purpose is to provide.

[0005]

In order to achieve the above-mentioned object, an automotive fuel pipe hose according to the present invention comprises an inner pipe layer having a single layer or multiple layers, and an outer pipe formed on the outer periphery of the inner pipe layer. A fuel hose for an automotive fuel line, comprising:
At least one of the inner tube layers is formed of a resin composition comprising the following component (A). (A) The following (a) and (b) are the main components, and the mixing ratio (a / b) of the following modified polyolefin (a) and polyamide resin (b) is a / b = 70/30 by weight ratio. ~ 1
0/90, ε-caprolactam as plasticizer
There resin composition is blended in a proportion of 1-10 wt% of the total tree fat composition. (A) Modified polyolefin. (B) Polyamide resin.

[0006]

In other words, the present inventors have conducted a series of studies in order to obtain a hose for automobile fuel piping which is excellent not only in gasoline permeability but also in kink resistance, assembly workability and flexibility. As a result, modified polyolefin and polyamide resin
When the inner tube layer is formed of a resin composition obtained by blending ε-caprolactam as a plasticizer with ε-caprolactam at a predetermined compounding ratio, the inner tube layer formed of the resin composition has a gasoline resistant property due to the properties of the polyamide resin. It has excellent permeability, and because it contains modified polyolefin, it is rich in flexibility and sealability is improved . Furthermore, ε-caprolactam
Is added as a plasticizer, so the flexibility of the inner tube layer is improved.
And the adhesiveness to the outer tube rubber layer is improved . Accordingly, the kink resistance of the entire hose is improved, and the assembling workability is also improved. Further, they have found that the flexibility of the whole hose is improved, and have reached the present invention.

Next, the present invention will be described in detail.

[0008] The automotive fuel pipe hose of the present invention comprises a modified polyolefin (a) and a polyamide resin (b) as main components , and ε-caprolactam as a plasticizer.
Inner tube layer (single-layer or multi-layer structure) formed at least one layer by resin composition (component A) mixed in proportion
And an outer layer formed on the outer periphery of the inner tube layer .

At least one of the inner tube layers contains a modified polyolefin (a) and a polyamide resin (b) as main components.
And ε-caprolactam as a plasticizer at a specific ratio
Obtained by using the resin composition (A component) blended in the above.

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 a derivative thereof. 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 derivative of the unsaturated carboxylic acid include acid anhydrides, amides, esters and acid halides. These may be used alone or in combination of two or more. Then, such a graft polymerization component is used in the range of 0.1 to 20 mol% in the produced graft polymer.

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

The mixing ratio (a / b) of the modified polyolefin (a) and the polyamide resin (b) is expressed as
It is preferable to set a ratio of / b = 70/30 to 10/90. That is, when the blending ratio of the polyamide resin (b) is more than 90 (modified polyolefin is less than 10), the gasoline permeability is extremely excellent, but the flexibility, the kink resistance, the assembling workability and the sealing property are inferior, and the polyamide resin is poor. If (b) is less than 30 (modified polyolefin exceeds 70), flexibility, kink resistance, assembling workability and sealing properties are extremely excellent, but gasoline permeability resistance is inferior.

[0013] Then, the resin composition of the present invention (component (A))
In addition to the modified polyolefin (a) and the polyamide resin (b), ε-caprolactam, which is widely used as a raw material monomer for nylon 6, is compounded for the purpose of plasticizing action. By blending this ε-caprolactam as a plasticizer, the resin composition can be softened, and the flexibility, kink resistance, assembling workability and sealability of the resulting hose can be improved. Furthermore, ε-caprolactam can improve the adhesion to the outer tube rubber layer. And the compounding amount of the above-mentioned ε-caprolactam is 1 to the entire resin composition (A component).
It is set to a ratio of 15% by weight. That is, when the amount of ε-caprolactam exceeds 15% by weight, the resulting gasoline has a tendency to deteriorate in gasoline permeability.

[0014] In addition to the modified polyolefin (a), the polyamide resin (b) and ε-caprolactam, the resin composition (component A) may optionally contain various additives such as an antioxidant and a processing aid. An agent can be appropriately compounded.

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

[0017] 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 multilayer, at least one layer is extruded by the above-mentioned extrusion operation using the above-mentioned component A, and the other materials are otherwise repeated a plurality of times according to the layer constitution, or a multilayer is simultaneously extruded. An inner tube layer consisting of multiple layers is obtained. In addition, at the time of such multiple times of extrusion molding, an adhesive treatment may be appropriately performed between the layers of the inner tube layer composed of a plurality of layers.

Next, after applying an adhesive (rubber glue or the like) to the outer peripheral surface of the inner tube layer composed of the single layer or the multilayer as needed, a rubber composition for forming the outer tube layer is formed on the outer periphery. The target outer tube layer is obtained by extruding the product with an extruder.

The thus obtained laminated pipe is heated and vulcanized at a predetermined temperature to be integrated, whereby an intended automobile fuel pipe hose 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 ℃.

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

In the above-mentioned automobile fuel hose, a fiber reinforcing layer 4 may be provided between the inner pipe layer 2 and the outer pipe rubber layer 3 as shown in FIGS. The fiber reinforcing layer 4 is the same as that used for a normal rubber hose, and is formed by braiding or spiral knitting of a yarn mainly composed of synthetic fibers such as polyester fibers and aramid fibers.

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

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

In the automotive fuel piping hose of the present invention, the thickness of each layer is appropriately set according to the type of the material forming them, the thickness of the hose, and the like. For example,
Assuming that the inner diameter of the hose is 1, the relative values are the inner tube layer 2,
The thickness of 2a is preferably set to 1/30 or more,
It is preferable that the thickness of the outer tube layer 3 is set to 1/6 or more. Specifically, the inner diameter of the hose 1 is 3.0 to 15.0 m
m, the thickness of the inner tube layers 2 and 2a is 0.1 to 1.5 mm
, And the thickness of the outer tube layer 3 is preferably set in a range of 1.5 to 4.0 mm.
Particularly preferably, the thickness of the inner tube layers 2 and 2a is 0.3 to 0.5.
5 mm, and the thickness of the outer tube layer 3 is 2.7 to 2.9 mm.
When the inner tube layer 2a has a multilayer structure as shown in FIG. 5, the thickness of the resin layer 5 as the innermost layer is 0.1 to 0.5 m.
m, the thickness of the inner tube resin layer 6 is preferably set to 0.1 to 1.5 mm.

Further, in the hose for an automobile fuel pipe of the present invention, the bending elasticity of the inner tube 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). The rate is 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), and particularly preferably 60 to 70 (Hs).
s). By setting the characteristics of each layer as described above, a hose excellent in kink resistance, flexibility, airtightness, workability in assembling (insertability into a metal pipe), and the like can be obtained.

When the inner pipe layer is a single-layered hose (see FIGS. 1 and 2), the hose for an automobile fuel pipe obtained as described above is connected to a metal pipe 8 as shown in FIG. Fitted and used for fuel piping.

[0027]

As described above, the automotive fuel pipe hose of the present invention comprises the modified polyolefin (a) and the polyamide resin (b) blended at a predetermined blending ratio as main components.
And ε-caprolactam as a plasticizer at a specific ratio
The outer tube layer is formed on the outer peripheral surface of the inner tube layer formed by the resin composition (A component) blended in the above. For this reason, the inner tube layer is excellent in gasoline permeation resistance and excellent in flexibility while being excellent in kink resistance, sealability, assembling workability, and pressure resistance due to the material of the inner tube layer. And
The adhesion between the inner tube layer and the outer tube rubber layer is also good, and the hose as a whole is also rich in flexibility and the like. Therefore, the automotive fuel pipe hose of the present invention is most suitable for, for example, an evaporative hose, a breather hose, a fuel hose, and the like for connecting a gasoline tank and an engine of an automobile, and has a very high use 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] A modified polyolefin and polyamide resin shown in Table 1 below and various additives were blended at the ratio shown in the table and mixed to prepare a resin composition. In Table 1 below, PA6 is nylon 6.

[0031]

[Table 1]

[0032]

Examples 1 to 3 and Comparative Examples 1 to 6 Using the raw materials shown in Tables 2 to 4 below, hoses for automobile fuel piping were obtained according to the above-mentioned production 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 2 to 4 below. The vulcanization conditions are as follows:
Set at 150 ° C. for 35 minutes. Also, C in Tables 2 to 4
R is chloroprene rubber. And the bending elastic modulus of the said 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
(± 0.5 mm, thickness: 4 ± 0.2 mm). Then, using the device shown in FIG.
The test piece 7 was suspended over the sample, 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 equation.

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 part of the first straight line of load-deflection curve (Kgf) Y: Deflection at load F (cm)

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

The gasoline permeation resistance, kink resistance, flexibility, airtightness, assembly workability, and pressure resistance of each of the automobile fuel pipe hoses obtained as described above were measured and evaluated. In addition, the flexural modulus of the inner layer of the automotive fuel pipe hose as an example was measured. Then, from the above measurement results, each hose was comprehensively evaluated in three steps. That is, ○ was excellent, △ was normal, and × was inferior. The results are shown in Tables 5 and 6 below. The evaluation of each of the above properties was measured according to the following method.

[Gasoline Permeation Resistance] As shown in FIG. 8, a sample (hose) 10 cut to a specified length (free length 500 mm) is fitted into two pipes 13 and 14 of a fuel tank 12 and clamped by a clamp 15. Fixed. Next, the fuel tank 12 has a capacity of 8 tanks.
The sample fuel (regular gasoline) 11 is filled up to 5%, and the fuel
It was left for 168 hours in a thermostat at ℃. Then, after standing, the sample 10 was removed from the fuel tank 12 and
The two ends of the sample 10 are fitted into two pipes 17 and 18 formed on the upper surface of the fuel tank 16 shown in FIG.
Fixed at 5. Next, the fuel tank 16 was filled with about 100 cc of new prescribed gasoline 11, and the inside of the sample 10 was made into a gasoline vapor shape. Then, in this state, the entire weight was measured in a constant temperature bath at 40 ° C. every 24 hours for 3 days.
Then, the gasoline permeation amount was calculated by the following equation.

Θ = [Wn−W (n−1)] / S [In the above equation, Θ represents the amount of transmission 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. ]

[0040] And, those of less than 100g / m ² / day is one of ^{○, 100~300g / m 2 / day} △,
Those exceeding 300 g / m ² / day were indicated as x.

[Kink Resistance] As shown in FIG. 10, a loop was formed using a sample (hose) 19 having a length of 1 m, the intersection was held by hand, and the sample 19 was pulled in the direction of the arrow for one minute. Held. After holding, R
The outer diameter D ₁ (mm) of the sample 19 in each part was measured, and the retention was determined. Next, the diameter of the ring at the R portion where the kink was obtained by further reducing the diameter of the ring was determined. The retention was calculated by the following equation.

Retention (%) = (D ₁ / D) × 100 [In the above equation, D is the initial outer diameter (mm) of the sample (hose). However, a minor diameter of the sample (hose) outer diameter with D ₁ and D. ]

Then, those kinked with R less than 70R are indicated by ○, those kinked by R in the range of 70R to 100R are indicated by Δ, and those kinked by R larger than 100R are indicated by ×.

[Flexibility] A sample (hose) having a length of 150 mm was prepared and measured based on a three-point bending test method in a plastic bending test method. That is, as shown in FIG. 11, the hose 21 is bridged between the two support bases 20 and the pressure wedge 22 is lowered from the center of the hose 21 at a speed of 30 mm / min.
The relationship between the displacement and the load at this time was measured.

Then, when the load at a displacement of 10 mm is 1.
Those with less than 5 kgf / cm ² are ○, 1.5-3.0 kg
Those with f / cm ² were indicated as Δ, and those with more than 3.0 kgf / cm ² were indicated as ×.

[Airtightness] As shown in FIG. 12, a 300 mm long sample (hose)
Both ends of 23 were fixed to a pipe 25 of a fixing jig 24. Then, air (or an inert gas) was sent from the direction of the arrow to the hole at the end of the fixing jig 24 to fill the inside of the hose 23 with a specified pressure and dipped in the water tank. After a lapse of a prescribed time, the presence or absence of leakage of the pressurized gas was examined.

Then, 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 ×.

[Assembling workability] As shown in FIG. 13, a sample (hose) 2 having a length of 50 mm was used.
6 is set upright, and the pipe 28 attached to the compression tester 27 is connected to the hose 2 at a speed of 30 mm / min in the direction of the arrow.
6 was inserted. The maximum load during the insertion was measured.

Those having a weight of less than 15 kgf are rated as ○, 15
~ 30kgf is △, and over 30kgf is ×
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, the pressure was measured at a pressure of 70 kgf / cm ² per minute and the pressure at the time of rupture was measured.

[0051] and, more than 50kgf / cm ² is ○, those of 10~50kgf / cm ² △, 10kg
Those with less than f / cm ² were indicated as x.

[0052]

[Table 5]

[0053]

[Table 6]

From the results in Tables 5 and 6 , the product of the example was
It can be seen that while having excellent gasoline permeation resistance, it also has excellent kink resistance, flexibility, airtightness, workability in assembling, and pressure resistance.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of the hose for automobile fuel piping.

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

FIG. 4 is a longitudinal sectional view of the hose for an automobile fuel pipe.

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

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

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

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

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

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

FIG. 11 is an explanatory view showing a method for measuring and evaluating the flexibility of a hose for an automobile fuel pipe.

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

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

[Explanation of symbols]

 2 Inner tube layer 3 Outer tube rubber layer

Continuation of front page (56) References JP-A-5-44874 (JP, A) JP-A-60-173047 (JP, A) JP-A-2-11647 (JP, A) JP-A-60-960 (JP) JP-A-59-193959 (JP, A) JP-A-1-171939 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 F16L 9/00-9/22 F16L 11/00-11/24 EPAT (QUESTEL) WPI / L (QUESTEL)

Claims (3)

(57) [Claims] 1. A hose for an automotive fuel pipe comprising an inner pipe layer composed of a single layer or multiple layers, and an outer pipe layer formed on the outer periphery of the inner pipe layer, wherein at least one of the inner pipe layers is provided. An automotive fuel piping hose formed of a resin composition comprising the following component (A): (A) The following (a) and (b) are the main components, and the mixing ratio (a / b) of the following modified polyolefin (a) and polyamide resin (b) is a / b = 70/30 by weight ratio. ~ 1
0/90, ε-caprolactam as plasticizer
There resin composition is blended in a proportion of 1-10 wt% of the total tree fat composition. (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 of the outer tube layer is set to be at least 1/6 with respect to the inner diameter of the hose being 1 or more.
The hose for an automotive fuel pipe according to the above. 3. The thickness of the inner tube layer is set to 1/30 to 1/4 when the inner diameter of the hose is 1, and the thickness of the outer tube layer is set to 1/2 to 1/1 when the inner diameter of the hose is 1. The hose for an automotive fuel pipe according to claim 1 or 2 , wherein the hose is set to a dimension of 6.