JP2932980B2 - 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 a hose for a fuel pipe of an automobile.

[0002]

2. Description of the Related Art As a fuel hose for automobile fuel pipes, a hose having a fluororesin layer as a gasoline barrier layer has been spotlighted in accordance with the tightening of vaporized gas regulations (SHED) in the United States. JP-A-5-44874 discloses a structure in which a fluorine resin such as tetrafluoroethylene-ethylene copolymer or polytetrafluoroethylene having a low gasoline permeability and a low permeability is used for an inner layer and epichlorohydrin rubber is used for an outer layer. Have been. In this case, adhesion between the inner resin layer and the outer rubber layer is performed by subjecting the surface of the inner resin layer to a corona discharge treatment or a UV irradiation treatment, and then having a gasoline resistant, flexible, heat resistant thermosetting adhesive. It is adhered using. JP-A-6-99548 discloses a structure in which a fluorine resin such as polyvinylidene fluoride or polychlorotrifluoroethylene is used for an inner layer, and a rubber elastic material such as a nitrile butadiene rubber or epichlorohydrin rubber is used for an outer layer. Have been. In this publication, there is no remarkable description about the adhesion between the inner resin and the outer rubber. However, the adhesion between the fluororesin and the rubber elastic material such as NBR rubber cannot be obtained by the ordinary vulcanization bonding, so that the bonding is ultimately performed by applying a surface treatment such as corona discharge. It seems that the material must be modified to be easy to use.

On the other hand, Japanese Patent Publication No. 59-38896 discloses a common case in which a fluorine rubber which is a terpolymer of vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene is used for an inner layer and an epichlorohydrin rubber is used for an outer layer. When a divalent metal oxide or hydroxide, a fluorine-containing polyhydroxy compound and an organic compound containing a nitrogen or phosphorus atom in a molecule are added as vulcanization system components, the compatibility between the two rubbers is inherently increased. It is disclosed that the adhesiveness which has a problem in lamination due to badness or different vulcanization systems is remarkably improved.

Further, Japanese Patent Publication No. 60-33663 discloses that in the case of the inner layer fluororubber and the outer layer epichlorohydrin rubber, the carboxylic acid 1.8-diazabicyclo [5.4.
0] It is described to incorporate undecene-7 salt. Japanese Patent Application Laid-Open No. 5-214118 discloses that a phosphonium salt is interposed between rubber layers in producing a laminate comprising a fluororubber layer and another rubber layer.

[0005]

The above-mentioned fluororesins are all hard and lack flexibility, and are very difficult to use when formed into a hose, and secure sealing properties with a joint pipe. This also had drawbacks. In addition, since it is extremely difficult to perform surface treatment such as corona discharge over the entire inner surface of the long hose-shaped fluorine-based resin layer, a rubber layer is provided on the innermost layer in order to improve sealing properties. Even if we wanted to, it was difficult.

The present invention has been made in view of the above-mentioned drawbacks of the conventional products,
The purpose is to provide a suitable flexibility as a hose, and furthermore, when disposing a desired rubber layer on the outside or inside of the fluororesin layer, without subjecting the surface treatment such as corona discharge to rubber, It is an object of the present invention to provide an automotive fuel piping hose capable of obtaining a sufficient bonding strength only by vulcanization bonding with a layer.

[0007]

The automotive fuel piping hose according to the present invention is an inner layer formed of a tertiary fluororesin (hereinafter referred to as F resin) of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride. And 1
Epichlorohydrin rubber (hereinafter, referred to as ECO) in which 8-diazabicyclo [5.4.0] undecene-7 salt (hereinafter, referred to as DBU salt) and an organic phosnium salt are blended.
An outer layer that is a vulcanized molded product of a vulcanizing composition of a blend of nitrile butadiene rubber and a polyvinyl chloride resin (hereinafter, referred to as NBR / PVC); B. The innermost layer which is a vulcanized molded product of a vulcanizing composition of a nitrile-butadiene-based rubber or a fluororubber containing a U salt and an organic phosphonium salt,
It is formed by strong vulcanization bonding.

[0008]

[Action] The flexural modulus of general fluororesin is 7000
While stiff and 9000Kgf / cm ^2, the F resin used in the present invention because it is soft and 2000~2800Kgf / cm ^2, can be provided with a preferred flexibility when the hose.

In the present invention, ECO or NBR / PVC exhibiting excellent ozone resistance is disposed on the outer layer outside the inner layer formed of the F resin, and excellent on the innermost layer inside the inner layer. Nitrile butadiene rubber exhibiting gasoline resistance (in the present invention, nitrile butadiene rubber is NB
Not only R but also hydrogenated NBR and NBR / PVC are included. ) Or fluoro rubber is provided. Both the outer layer and the innermost layer of the vulcanizing composition have D.I. B. A U salt and an organic phosphonium salt are blended so that a good adhesion strength can be obtained by ordinary vulcanization without special surface treatment of the F resin.

Organic phosphonium salts and D.C. B. As the compounding ratio of the U salt, the organic phosphonium salt is 0.2 to 5.
0 phr, D.I. B. The U salt is 0.5-6.0 phr, preferably the organic phosphonium salt is 1.0-2.0 phr. B.
U salt 2.0-4.0 phr. Organic phosphonium salts, D.I. B. If the amount of U salt used is small, the adhesive strength is weak,
When used in a large amount, the compression set becomes poor.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment shown in FIGS.
The tertiary fluororesin of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride is commercially available from 3M under the trade name THV. As the THV, it is also possible to adopt a conductive THV (ESD) as a measure against static electricity, that is, a mixture of THV and conductive carbon or the like.

The outer layer 2 formed outside the inner layer 1 is
It may be made of ECO or NBR / PVC, and the outer layer 2 may be provided with a reinforcing layer 3 made of polyester fiber or the like if necessary. The innermost layer 4 formed inside the inner layer 1 is made of NBR rubber or fluoro rubber. The innermost layer 4 may be formed on the entire inner surface of the hose (see FIG. 1), or may be formed only on the end of the hose corresponding to the insertion point of the joint pipe. A seal lip (not shown) may be formed on the surface of the joint to further ensure the sealing performance with the joint pipe.

The outer layer 2 and the innermost layer 4 are provided so that the hoses shown in FIGS.
All of the vulcanizing compositions that constitute B. U
Salt and organic phosnium salt are blended. in this regard,
More specifically, ECO which is a material for forming the outer layer 2 is used.
Is usually 50 phr of carbon and 15 p of basic silica with respect to 100 parts by weight of ECO (Epichromer C manufactured by Daiso).
hr, plasticizer 20 phr, Ca (0H) ₂ 15 phr, stearic acid 5 phr, MgO 1 phr, lead oxide (Pb ₃ O ₄ 5
phr and 2 phr of a urea-based vulcanizing agent are blended. In this usual blending, two unvulcanized rubber sheets (about 150 mm × 15 mm) are used.
0mm, thickness 2-3mm) sandwich the fluororesin sheet between
Wound around an iron pipe with an outer diameter of about 70 mm, and further wrap a polyester cloth (about 25 mm in width) from above, put it directly into a steam pot (160 ° C) for 20 minutes and vulcanize it. When a test piece is sampled at an inch width and the test piece is subjected to a 180 ° peel test at a speed of 50 mm / min,
At a peel strength of about 0.8 kgf / inch, interfacial peeling occurs. However, 0.2 phr of an organic phosphonium salt (Dynamar FX-5166 manufactured by 3M) was added to the above composition.
And D. B. U salt (P-152 made by Daiso) 0.5 ph
r, 1.5 phr of polyol, 10 Kgf peel strength
/ inch until partial interfacial destruction occurred, and an organic phosphonium salt of 1.5 phr, D.I. B. Assuming that the U salt is 3.0 phr and the polyol is 1.5 phr, rubber breakage is caused at a peel strength of 15 kgf / inch or more. However, the organic phosphonium salt 5.0 phr, D.C. B. Even if the U salt is increased to 6.0 phr, not only does the rubber breakage occur at a peel strength of 15 kgf / inch or more, but also the compression set becomes poor when used in large amounts. Therefore, the preferable addition amount is 1.0 to 2.0 phr of the organic phosphonium salt, B. U salt 2.0-4.0
phr.

Here, the organic phosphonium salt is a quaternary phosphonium salt containing an alkyl group having 1 to 20 carbon atoms or a quaternary phosphonium salt containing an aromatic substituent.
Tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, tributyl (methoxypropyl) phosphonium chloride, benzyltriphenylphosphonium chloride, benzyltrioctylphosphonium chloride, triphenylbenzylphosphonium chloride, tetraalkylphosphonium benzotriazole (tetrabutylphosphonium chloride, tetraalkylphosphonium Benzotriazole (tetrabutylphosphonium benzotriazole, trioctylethylphosphonium benzotriazole) and the like.

The 1,8-diazabicyclo (5,4,0) undecene-7 salt, abbreviated as DBU salt, includes:
DBU or its weak acid salt is blended, and carbonate, long chain fatty acid, carboxylate, aromatic sulfonate or carboxylate, phenol salt, thiol salt and the like can be adopted from the viewpoint of handling. Typical are DBU-carbonate,
DBU-naphthoate, DBU-P-hydroxy-benzoate, DBU-P-toluenesulfonate and the like.

The innermost layer 4 NBR (JSR made by Nippon Synthetic Rubber Co., Ltd.)
N220S), carbon 40 phr, basic silica 20 phr, Ca (0H) ₂ 15 phr, plasticizer 10 p
hr, zinc flower 5 phr, stearic acid 1 phr, sulfur 0.5
phr, peroxide (Kayakumil D40 manufactured by Kayaku Nouri)
C) With a normal formulation of 7.0 phr, a peel strength of 0.7
Interfacial peeling occurs at about Kgf / inch, but 0.2 phr of an organic phosphonium salt and D.C. B. U salt 0.2 ph
When r was added, partial interfacial delamination occurred at a peel strength of 13 kgf / inch, and the organic phosphonium salt was 1.5 phr and the D.E.
B. By setting the U salt to 3.0 phr, the peel strength is 15 kgf / in.
Until the rubber break occurs at ch or more. Hydrogenated NBR
(Zeon Pole 1020 manufactured by Zeon Corporation) and NBR /
PVC (Nippon Zeon's DN502) was also examined, and the results are almost the same as in the case of NBR. The preferable addition amount is 1.0 to 3.0 p of the organic phosphonium salt.
hr, DBU salt 2.0-5.0 phr.

The innermost layer 4 is made of fluorine rubber (TX manufactured by Zeon Corporation).
348E) also has a carbon content of 10 phr and Ca (0
H) The ₂ 6 phr, usually the formulation was polyol 2.5 phr, but resulting in interfacial peeling at about peel strength 1.3 kgf / inch, D. and organic phosphonium salt 0.2 phr of the above formulation
B. When 0.5 phr of U salt is added, peel strength is 10kgf / inch
At 1.5 phr of organic phosphonium salt, D.C. B. At a U salt of 3.0 phr, rubber breakage occurs at a peel strength of 15 kgf / inch or more. However, organic phosphonium salts, D.I. B. 5.0 phr for both U salt
There was no change in that rubber breakage occurred at a peel strength of 15 kgf / inch or more.

Table 1 shows that the fluororesin is THV or ETF.
This is an experimental example in which a change in the adhesive force when the rubber material was changed was measured in the case of E. In this case, when ETFE is used as the fluororesin, an organic phosphonium salt is used as the rubber material. B. Even with the addition of U salt, satisfactory adhesion could not be obtained.

Table 2 shows the characteristics of the hose according to the present invention. In the table, those with a “revision” added to the end of the symbol indicating the material are the above-mentioned organic phosphonium salts, D.I. B. It shows that U salt was added.

A comparative example is shown in which a tetrafluoroethylene-ethylene copolymer (LM740, manufactured by Asahi Glass Co., Ltd.) is used instead of the F resin. Also in this case, the organic phosphonium salt, D.I. B. Even with the addition of U salt, satisfactory adhesion could not be obtained.

[0021]

[Table 1]

[0022]

[Table 2]

Next, an example of the hose production according to the present invention will be briefly described as follows.

Production Example 1 (1) NBR rubber was extruded onto a mandrel of resin (methylpentene polymer) having an outer diameter of 6 mm (wall thickness: about 0.5 mm).
mm).

(2) On top of that, the extruder head was heated at a temperature of 250 to 300 ° C. and THV was extrusion-coated (with a wall thickness of about 0.2
mm).

(3) After the resin is uniformly coated and cooled, an ECO rubber is further extruded (with a thickness of about 1.5 m).
m).

(4) After coating the ECO rubber, it is wound up in a dish can and vulcanized at 155 ° C. for about 30 minutes in a steam pot.

(5) After cutting to a predetermined size, the core mandrel is pulled out to produce a final product.

(6) If necessary, add 150
The secondary vulcanization may be performed at a temperature of 1 to 3 hours.

In the above embodiment, the material of the innermost layer may be hydrogenated NBR. Manufacturing Example 2 (1) An NBR rubber is extrusion-coated (about 0.5 mm in thickness) on an aluminum pipe having an outer diameter of 37 mm.

(2) On top of that, the extruder head was heated at a temperature of 250 to 300 ° C. and extruded with THV (thickness of about 0.2 mm).
mm).

(3) After the above resin is uniformly coated and cooled, an ECO rubber is further extruded (with a thickness of about 3.3 m).
m).

(4) The aluminum pipe is pulled out, cut into a predetermined size, inserted into a metal mandrel of a predetermined shape and vulcanized (155 ° C., about 30 minutes in a steam pot). Completed by extracting.

(6) If necessary, add 150
The secondary vulcanization may be performed at a temperature of 1 to 3 hours.

Production Example 3 (1) THV is extrusion-coated on a thermoplastic elastomer mandrel having an outer diameter of 38 mm and an inner diameter of 27 mm (with a wall thickness of about 0.1 mm).
2 mm).

(2) After the resin is uniformly coated and cooled, NBR / PVC rubber is further extrusion-coated (thickness: about 3.3 mm).

(3) The thermoplastic elastomer mandrel is pulled out, cut into a predetermined size, inserted into a metal mandrel of a predetermined shape and vulcanized (at 155 ° C., about 30
Minutes). After vulcanization, remove the hose.

(4) An unvulcanized NBR tube (inner diameter 0.5 mm, length 35 mm) is inserted into both ends of the hose.

(5) Only this end is placed in a predetermined mold and kept at 150 ° C. and 15 ° C. while being restrained from inside and outside of the hose.
Vulcanize separately. As a result, a hose having the NBR seal rubber attached only to the inner surface of the end was obtained.

[0040]

As described above, the inner layer of the automotive fuel pipe hose according to the present invention is formed of a tertiary fluororesin molded article of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride. As a result, suitable flexibility was able to be provided.

Further, a vulcanizing composition of epichlorohydrin rubber or a blend of NBR / PVC disposed outside the inner layer made of the fluororesin, and a vulcanizing composition of NBR rubber or fluororubber disposed inside the blend. The objects are all 1.8-
By combining diazabicyclo (5.4.0) undecene-7 salt and organic phosphonium salt, sufficient adhesion strength is obtained only by adhesion by vulcanization without surface treatment such as corona discharge on the inner surface of the fluororesin. Is obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing one embodiment of a hose for an automotive fuel pipe according to the present invention.

FIG. 2 is a longitudinal sectional view thereof.

FIG. 3 is a partial sectional view showing another embodiment.

[Explanation of symbols]

 1 is an inner layer, 2 is an outer layer, 3 is a reinforcing layer, and 4 is an innermost layer.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazutaka Shirakami 58 Kamitomi, Kurashiki-shi, Okayama Marugo Rubber Industry Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) B32B 1/00 -35/00 F16L 11/04-11/12 C08J 5/12

Claims (1)

(57) [Claims] 1. An inner layer which is a molded product of a ternary fluororesin of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride, and 1.8-diazabicyclo (5.4.0) undecene-7.
An outer layer which is a vulcanized molded product of a vulcanizing composition of an epichlorohydrin rubber or an NBR / PVC blend containing a salt and an organic phosphonium salt, and 1.8-diazabicyclo (5.4.0) undecene-7
A hose for automobile fuel piping, wherein an inner layer which is a vulcanized molded product of a vulcanizing composition of an NBR rubber or a fluororubber containing a salt and an organic phosphonium salt is firmly adhered to the hose.