JPS6022624B2 - rubber hose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber hose consisting of two or more layers in which the inner layer is made of fluororubber, and is particularly applicable to fuel hoses for automobiles and the like.

Today's fuel circuit hoses, especially automotive fuel hoses that are applied to fuel circuit systems equipped with electronic fuel injection devices, are prone to deterioration due to gasoline flowing inside the engine due to high temperatures or increased internal pressure, and sour gasoline resistant hoses are not suitable. sexuality is required.
In addition, fuel hoses are required to have improved resistance to alcohol-added gasoline due to deteriorating fuel conditions, as well as improved gasoline permeation resistance due to air pollution regulations. Therefore, various performances under various caustic conditions are required. Fluororubber is a rubber material that satisfies these various properties.

Fluororubber has excellent heat resistance, gasoline resistance, sour gasoline resistance, and gasoline permeation resistance. Therefore, it is desirable to use this fluororubber as the inner layer material for fuel hoses, but fluororubber is very expensive at 10 to 2 pm compared to other rubber materials such as NBR and CHR, so it is difficult to use from a cost standpoint. Therefore, it is desirable to make the inner layer made of fluororubber thin. However, if this inner layer is made too thin (
0.2 side or less), sour gasoline, etc. permeate the inner layer and reach the rubber layer circumscribing the inner layer, degrading the rubber layer, so there may be cases where the excellent performance of fluororubber cannot be utilized. In view of the above, the present invention provides a rubber hose consisting of two or more layers in which the inner layer is made of fluororubber.
To provide a rubber hose capable of maintaining various excellent performances of fluororubber even if the inner layer is made thin.

The first invention achieves the above object by forming a circumscribing layer on a thin inner layer made of fluororubber with a blend rubber of a specific ratio of NBR and fluororubber; This is achieved by forming the layer circumscribing the thin inner layer of fluororubber from a blend rubber of NBR and fluororubber to which an olefin-ester acrylate copolymer has been added.

EMBODIMENT OF THE INVENTION Hereinafter, the rubber hose of this invention is demonstrated in detail based on the example of a figure.

Here, as shown in Fig. 1, a thin inner layer made of fluororubber (inner tube first layer) 1, a layer circumscribing this inner layer (inner tube second layer) 2, a rice bran reinforcing yarn layer 3, and an outer layer The explanation will be given using a fuel hose consisting of a pipe 4 as an example, but it is not limited to this, and various types such as a two-layer type with only a layer circumscribing the inner layer, or a non-reinforced yarn type without a wire reinforcement yarn layer, etc. The present invention is applicable to rubber hoses consisting of more than one layer.

The first layer 1 of the inner tube is made of fluororubber, and specifically, the first layer 1 is made of fluorine rubber.
, 1-difluoroethylene-hexafluoropropylene copolymer, 1,1-difluoroethylene-hexafluoropropylene-tetrafluoroethylene terpolymer,
1,1-difluoroethylene-chlorotrifluoroethylene copolymer, 1,1-difluoroethylene-perfluoroacrylic acid derivative copolymer, 1,1-difluoroethylene-perfluorovinylether copolymer, etc., or these An example is a blend of

Among the above examples, 1,1-difluoroethylene-hexafluoropropylene copolymer and 1,1-difluoroethylene-hexafluoropropylene-tetrafluoroethylene terpolymer are particularly preferred. In addition, the first inner pipe
The thickness of the layer is 0.2 to 1.0 ribs. The inner tube second layer 2 is
It is formed of a blend rubber of NBR and fluororubber (component A), or a blend rubber in which 1 to 2 parts by volume of an olefin-acrylic acid ester copolymer (component B) is added to 10 parts by volume of component A.

Here, NBR in component A refers to conjugated gene and 〇,
It refers to a copolymer with 3-unsaturated nitrile, and examples of the conjugated diene include 1,3-butadiene, 2-methyl-1,3-butadiene, 2-chloro-1,3-butadiene, and 1,3-bentadiene. , as an unsaturated nitrile,
Examples include acrylonitrile, methacrylonitrile, and Q-chloroacrylonitrile.

In the above examples, 1,3-butadiene is preferred as the conjugated diene, and acrylonitrile is preferred as the unsaturated nitrile. Regarding the content of unsaturated nitriles in NBR, 43~
6 skin t%. If the content is 4 t%, it lacks compatibility with fluororubber, and if it exceeds 6 t%, it lacks flexibility (rubber-like elasticity decreases), which is undesirable.

There is no particular restriction on the molecular weight of NBR, but Mooney viscosity (M
L+4100q0) is preferably 30 to 150. In addition, the fluororubber in component A is
Using the materials exemplified in the layer, the blending ratio of fluororubber to NBR is 25 to 95 vol %, with the remainder being NBR. At this time, if the fluororubber content is less than 25 vol %, physical property problems such as sour gasoline resistance will occur in the second layer of the inner tube, and the adhesive strength with the first layer of the inner tube will also decrease. If it exceeds 95 vol%, it will not be cost effective.

In addition, as the olefin in component B, the carbon number is 2 to
20 linear or branched unsaturated hydrocarbons, preferably unsaturated hydrocarbons having 2 to 8 carbon atoms.

These unsaturated hydrocarbons include ethylene, propylene,
Isobutylene, bentene-1,2-methylbentene-1
, hexene-1, butene-2, 4-methylbentene-1
, 2-methyl-4-phenylbutene-1, octadecene-1, 1,3-butadiene, 1,3-pentadiene, 2
-Methyl-1,3-butadiene, 1,4-hexadiene, 1,3,5-hexatriene, 2-chloro-1,3-
Examples include butadiene, 2-methyl-4-chlorobentene-1, and ethylene is particularly preferred. The acrylic acid ester is represented by the following general formula.
However, R,, R2: hydrogen, a hydrocarbon group having 1 to 10 carbon atoms, halogen, or a halogenated hydrocarbon group having 1 to 10 carbon atoms.

R3: A hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon.

Specifically, methyl acrylate, propyl acrylate,
Allyl acrylate, crotyl acrylate, acrylic acid n
-butyl, t-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, ethylhexyl acrylate, cyclobentenyl acrylate, o-tolyl acrylate, pendyl acrylate, cyclohexyl acrylate, and these acrylic acids Hydrocarbon group at Q position or 8 position,
It has a substituent such as a halogenated hydrocarbon group or halogen.

The blending ratio of monomers in the IB component is olefin 10
~7 melon hol%, the remainder being acrylic acid ester.

Furthermore, it is preferable that component B be copolymerized with a third component monomer that provides sulfur crosslinking points and amine crosslinking points at a ratio of within 1.5 hol%.

This third component monomer includes polyene hydrocarbon,
Acrylic acid unsaturated ester, acrylic acid unsaturated amide,
Halogen-containing acrylic acid esters, ethylenically unsaturated carboxylic acids, halogen-containing unsaturated hydrocarbons, etc. can be used, and specifically, dipynylbenzene, 5-ethylidene-2-norbonene, cyclohexenyl acrylate,
N-1'-probenylacrylamide, acrylic acid 2-
Examples include chloroethyl, acrylic acid, methacrylic acid, and p-bromomethylstyrene. There is no particular restriction on the molecular weight of component B, but one with an intrinsic viscosity (30 qo in benzene solution) of 0.3 to 1/unit is preferred.

The blending ratio of component B to 100 parts by volume of component A is as described above, but is preferably 5 to 1 part by volume.

If component B is less than 1 part by volume, the effect of increasing the compatibility between NBR and fluororubber and improving physical properties will be small; if it exceeds 2 parts by volume, problems in physical properties will occur in the resulting second layer of the inner tube. arise. In addition, when the second layer of the inner tube is formed of a blended rubber containing component A and component B, the physical properties of the second layer of the inner tube are improved, especially sour gasoline resistance, compared to the case where component A is used alone. And the vulcanization adhesion with the first layer of the inner tube is improved.

This is thought to be because the fluororubber becomes a sea phase. Each of the above rubber materials includes various auxiliary materials normally used,
For example, inorganic fillers such as carbon black, silica, metal oxides, organic fillers such as gnin, softeners, plasticizers, antioxidants, colorants, etc. are appropriately blended, and organic peroxides and polyamines are also added. , add a thinning agent such as sulfur as appropriate, mix the wires, and then simultaneously form the first layer 1 and the second layer 2 of the inner tube with one extruder, or form the second layer on the first layer of the inner tube with another extruder. Extrude and shape.

The mandrel used at this time is made of nylon or rubber. Further, a striped reinforcing thread 3 is formed on the second layer 2 of the inner tube, and after applying an adhesive, an outer tube is extruded and molded using an extruder. At this time, the rubber material for the outside is not particularly limited, and synthetic rubbers such as CSM, CR, and CHR are used. The vulcanization conditions are a temperature of 145 to 170 qo and a temperature of 30 to 30 cm. Even if the rubber hose manufactured in this way has a thin inner layer made of fluororubber, as shown in the examples below,
Various properties of fluororubber, especially sour gasoline resistance, can be maintained, and interlayer adhesion between the inner layer and the layer circumscribing the inner layer is also good. Therefore, there is no need to make the inner layer made of fluororubber thick, and the manufacturing cost of the hose as a whole is reduced. Examples will be described below along with comparative examples to confirm the effects of the present invention. The first layer of the inner tube and the second layer of the inner tube used in the Examples and Comparative Examples are made of materials having the compositions shown in Tables 1 and 2, respectively.

The test piece for the sour gasoline resistance test has a wall thickness of 0.2
After extruding the ribs (first layer) and the 1.8 side (second layer), a rice bran reinforcing yarn layer was formed and an outer tube made of CR was extruded.
The hose was manufactured by vulcanization at 0×6 hin, and 10
It was created by cutting it to size. In addition, the glabellar adhesion test piece was made using two rubber materials for the first layer and second layer of the inner tube.
Layer the rolls of skin in sheet form and heat to 150℃.
It was created by pressure vulcanization at 100k9f/hin x6 mounds. The method of each experiment is as follows. Three test pieces were used for each item. Interlaminar adhesion strength (before Ganlin immersion)...Made in accordance with JIS-K-6301.

[B' interlayer adhesion strength (after Ganrin immersion)...After 4000 x 4 Tsumugi r immersion in Fuel D JISK-63
01.

'C} Sour gasoline resistance... After circulating Fuel C containing 1wt% lauryl baroxide at 200 valence r at an internal pressure of 2.5k9f/ x 23℃, the inner pipe walls of the hose come into contact with each other as shown in Figure 2. The inner tube is compressed several times until the inner tube is compressed several times, and the presence or absence of cracks in the first and second layers of the inner tube is visually determined.

Note that 0 means no cracks and × means cracks exist. From the test results shown in Table 2, the hoses to which the present invention was applied (Examples 1 to 6)
It can be seen that there is no discoloration in terms of sour gasoline resistance and adhesion between debris, even when compared to hoses in which the second layer of the inner tube is formed solely of fluororubber (Comparative Examples 1 and 3).

Further, it can be seen that the hoses in which the second layer of the inner tube was formed of NBR alone (Comparative Examples 2 and 4) had very poor sour gasoline resistance and interlayer adhesion and were not suitable for practical use. Table 1 *1) Tobiran connection, U.S. DuPont's unfitness, 1,1-difluoroethylene-hexafluoropropylene-7 Ethylene-hexafluoropropylene-tetrafluoroethylene ternary copolymerization Table 2 *1) Product name: Polyono crosslinked, manufactured by DuPont, USA
1 Curative 20: Organic phosphonium salt 33% Curative 30; Dihydroxy aromatic compound 50%*
2) Is the product also Japanese? Manufactured by Danji Co., Ltd., Yukiiso peroxide.

Table 3 *1) 1,3-butanene-acrylonitrile copolymer rubber with a bonded acrylic content of 48 *2) Product name,
1,1-difluoroethylene-hexafluoropropylene-tetrafluoroethane ternary combination vehicle needle *3) Product name, Dubonne acid list in the United States; Ethylene-
Methylacrylate-acrynoiso E-based copolymer Rubber component 81*.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a rubber hose to which the present invention is applied. FIG. 2 is a schematic view showing a sour gasoline resistance test method. 1... Inner tube first layer (inner layer), 2... Inner tube second layer (layer circumscribing the inner layer), 3... Line reinforcement yarn layer, 4... ...Outer tube. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A rubber hose comprising two or more layers in which the inner layer is made of fluorocarbon rubber, wherein the inner layer is thin, and
The layer circumscribing the inner layer has an unsaturated nitrile content of 43 to 60 wt.
% NBR and fluoro rubber 25-95vo
A rubber hose characterized in that it is formed of a blended rubber of 1%. 2. A rubber hose consisting of two or more layers in which the inner layer is made of fluorocarbon rubber, the inner layer being thin, and
The layer circumscribing the inner layer has an unsaturated nitrile content of 43 to 60 wt.
% NBR and fluoro rubber 25-95vo
l% of the olefin for 100 parts by volume of the blend
A rubber hose characterized in that it is formed of a blended rubber to which 1 to 20 parts by volume of an acrylic ester copolymer is added.