KR100683308B1 - Composition for producing of rubber fuel hose for vehicles and rubber fuel hose for vehicles - Google Patents

Abstract

A rubber fuel hose composition for vehicles is provided to contain no heavy metal, to cause no environmental problem, and to produce rubber fuel hoses having high heat resistance, gasoline resistance, and modified gasoline resistance. The rubber fuel hose composition for vehicles comprises: a base resin of epichlorohydrin-based polymer; a filler that is a single material selected from silica and carbon black, or a mixture of two or more; 1-10 parts by weight, based on the weight of the base resin, of a stabilizer as a hydrotalcite material; 10-30 parts by weight, based on the weight of the base resin, of a plasticizer as an ester-based material; and 0.5-2 parts by weight, based on the weight of the base resin, of a cross-linking agent as a thiourea material.

Description

Composition for producing rubber fuel hoses for vehicles and rubber fuel hoses for vehicles

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to.

1 is a partial cutaway view of a rubber hose according to the present invention.

2 is a process flowchart for explaining a method for manufacturing a rubber hose according to the present invention.

<Description of main parts of drawing>

10 ... rubber hose 12 ... inner layer 14 ... middle layer

16 ... braided layer 18 ... outer layer

The present invention relates to a composition for manufacturing a rubber fuel hose for a vehicle and a rubber fuel hose for a vehicle, and more particularly, a suitable selection of a material comprising the inner layer, the middle layer and the outer layer, in particular the inner layer uses a fluororubber composition, the middle and outer layers are silicone rubber The composition relates to a composition for manufacturing a rubber fuel hose for a vehicle and a rubber fuel hose for a vehicle in which adhesion between them is enhanced.

In industries where fuel hoses requiring heat resistance, pressure resistance, oil resistance, etc. are used, failure or accidents in the manufacturing process, as well as the required physical properties, may lead to equipment failure or accidents. In addition, due to the demand for continuous maintenance of these facilities, efforts and interests for producing rubber hoses having improved physical properties are being enhanced.

According to Japanese Patent Application Laid-Open No. 2000-313769, a rubber hose prepared by blending an epichlorohydrin rubber composition and a nitrile butadiene rubber composition and using sulfur crosslinking and a thiourea-based vulcanization accelerator is disclosed, which has low fuel oil resistance. And due to the low oil resistance has been pointed out a problem that is not optimized for the use environment, such as fuel hose for vehicles. On the other hand, Japanese Patent No. 10-264314 discloses a rubber hose made of an fluororubber composition with an inner layer and an epichlorohydrin rubber composition with an outer layer. However, it has low adhesion and low heat resistance, which makes it less suitable for use as an automotive fuel hose. have.

Meanwhile, in the case of a rubber hose manufactured by preparing a rubber composition to include heavy metals such as lead (Pb) or cadmium (Cd) for the purpose of enhancing oil resistance, oil resistance may actually be improved, but environmental regulations and The European Union's ban on heavy metals has limitations that cannot be used as a product. Therefore, while using a composition that does not contain heavy metals that are prohibited to use or regulated use, there is a need for the development of new materials capable of expressing heat resistance, oil resistance, etc. In the fuel hose manufacturing field in which oil such as gasoline is transferred therein, the necessity of solving the problems raised in the related art as described above is steadily recognized, and the efforts to solve the problems identified in the related art. The present invention has been devised under such a technical background.

The technical problem to be achieved by the present invention based on the above-mentioned conventional problems, when manufacturing a rubber hose using only a fluorine rubber composition having a strong oil resistance, while the unit cost is high, but when the production of a multilayer, the interlayer adhesion is not sufficient. The present invention is to solve the disadvantage that the suitability in use, such as a vehicle fuel hose that requires heat resistance, oil resistance, and the like, and to provide a composition for manufacturing a rubber fuel hose for a vehicle and a rubber fuel hose for a vehicle that can achieve such a technical problem. There is a purpose.

In order to achieve the technical problem to be achieved by the present invention, a composition for manufacturing a rubber fuel hose for a vehicle provided in the present invention, the base resin is an epichlorohydrin-based polymer; Filler, which is a single substance or a mixture of two or more selected from silica and carbon black; Hydrotalcite-based material, a stabilizer of 1 to 10 parts by weight based on the weight of the base resin; As the ester material, 10 to 30 parts by weight of a plasticizer relative to the weight of the base resin; And as a thiourea-based material, 0.5 to 2 parts by weight of the crosslinking agent relative to the weight of the base resin; characterized in that it comprises a.

The epichlorohydrin-based polymer used as the base resin is preferably a polymer in which two or three selected from epichlorohydrin, ethylene oxide and aryl glycidyl ether are mixed. The silica selected as the filler is preferably included in an amount of 5 to 30 parts by weight based on the weight of the base resin. The carbon black selected as the filler is preferably a furnace black, which is included in an amount of 20 to 80 parts by weight based on the weight of the base resin. The hydrotalcite-based material selected as the stabilizer is preferably Mg _4.5 Al ₂ (OH) ₁₁ (CO ₃ ) _0.8 O ₂ . The thiourea-based material selected as the crosslinking agent included in the epichlorohydrin rubber composition constituting the intermediate layer is thiourea, ethylene thiourea, ethyl thiourea, butyl thiourea, diethylthiourea, thibutylthiourea, and trimethyl. Preferred is any one or two or more materials selected from thiourea. The above-described composition for manufacturing a rubber fuel hose for a vehicle is a material in which 1,8-diazabicyclo (5.4.0) undec-7-ene and a liquid epoxy resin are mixed, and provides 0.5 to 5 parts by weight of the base resin by weight. My; A material in which nickel dibutyl dithiocarbamate and 2-mercapdobenzimidazole are mixed, 0.5 to 5 parts by weight of an antioxidant based on the weight of the base resin; And sorbitan monostearate, 0.5 to 5 parts by weight of the processing aid relative to the base resin weight; It is preferable to further include any one or two or more components selected.

In order to achieve the technical problem to be achieved by the present invention, a rubber fuel hose for a vehicle provided in the present invention includes an inner layer made of a fluororubber composition having a hollow interior and having an annular cross section; An intermediate layer made of the above-described composition coated while covering the inner layer; Braided layer made of organic fibers coated while covering the intermediate layer; And an outer layer made of the above-described composition coated while covering the braided layer.

Hereinafter, specific examples will be described in order to help the understanding of the present invention, and in the following case, with reference to the drawings will be described in more detail. However, embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

1 is a partial cutaway view of an embodiment of a rubber hose according to the present invention.

Referring to FIG. 1, the rubber hose 10 according to the present invention can confirm a structure composed of four layers of an inner layer 12, an intermediate layer 14, a braided layer 16, and an outer layer 18. The inner layer 12 is made of a fluororubber composition having a hollow interior and having an annular cross section, and the intermediate layer 14 is made of an epichlorohydrin rubber composition coated while covering the inner layer 12. The braided layer 16 is made of a coated fiber material surrounding the intermediate layer 14, and the outer layer 18 is made of an epichlorohydrin rubber composition coated while covering the braided layer 16.

The epichlorohydrin rubber composition forming the intermediate layer and the outer layer may include a base resin that is an epichlorohydrin-based polymer; A filler which is a single substance or a mixture of two or more selected from calcium silicate and carbon black; Hydrotalcite, which is 1 to 10 parts by weight based on the weight of the base resin stabilizer; As the ester material, 10 to 30 parts by weight of a plasticizer relative to the weight of the base resin; And a thiourea-based material, 0.5 to 2 parts by weight of the crosslinking agent, based on the weight of the base resin.

The epichlorohydrin polymer used as the base resin included in the epichlorohydrin rubber composition forming the intermediate layer and the outer layer is a polymer in which two or three selected from epichlorohydrin, ethylene oxide, and aryl glycidyl ether are mixed. As an epichlorohydrin-ethylene oxide copolymer or epichlorohydrin-ethyleneoxide-arylglycidylether terpolymer, and the like, for example.

The silica selected as the filler included in the epichlorohydrin rubber composition forming the intermediate layer and the outer layer is preferably included in an amount of 5 to 30 parts by weight based on the weight of the base resin. Regarding the numerical range of the content of silica used as the filler, if the lower limit is less than the lower limit, the improvement of workability is insignificant, and if the upper limit is exceeded, deteriorating the mechanical properties by acting as a foreign material according to the excessive use It can be a factor and is not desirable. On the other hand, the average particle size of the silica is preferably 20 to 40 nm.

The carbon black selected as the filler included in the epichlorohydrin rubber composition forming the intermediate layer and the outer layer is, as the furnace black, preferably 20 to 80 parts by weight based on the weight of the base resin. In this case, with respect to the numerical range for the carbon black used as the filler, when the lower limit is reached, the carbon black content is too small to decrease the tensile strength, and when the upper limit is exceeded, the elongation is lowered. I can't. On the other hand, the average size of the particles of carbon black used as the filler is preferably 20 to 40 nm, more preferably the surface area of 8 to 50 m 2 / g, the adsorption amount of dibutyl acrylic 30 to 150 cm 3/100 g.

A hydrotalcite-based material that is selected as the stabilizer contained in the intermediate layer, and epichlorohydrin rubber composition forming the outer layer, such as _{Mg 4 .5 Al 2 (OH)} 11 (CO 3) ₂ O is _0.8, and preferably, for this Regarding the numerical range of the content, it is not preferable that the heat resistance improvement is small when it is less than the lower limit, it is not preferable because the workability is unstable due to the high vulcanization rate when the upper limit is exceeded.

Regarding the numerical range of the content of the ester-based material selected as the plasticizer included in the epichlorohydrin rubber composition forming the intermediate layer and the outer layer, when the lower limit is not reached, the Mooney viscosity is increased and the workability is lowered, which is undesirable. When the upper limit is exceeded, the hardness and tensile strength, which are mechanical properties, are lowered, and the green strength is lowered, which makes the hose difficult to form, which is not preferable.

The thiourea-based material selected as the crosslinking agent included in the epichlorohydrin rubber composition forming the intermediate layer and the outer layer may be thiourea, ethylenethiourea, ethylthiourea, butylthiourea, diethylthiourea, thibutylthiourea, And trimethylthiourea is preferably any one or two or more materials selected. On the other hand, with respect to the numerical range for the content of the thiourea-based material selected as the crosslinking agent, if the lower limit is less than the crosslinking rate is low, the heat resistance is lowered, and if the upper limit is exceeded, the crosslinking rate is faster and mechanical It is unpreferable because physical property falls.

The epichlorohydrin rubber composition forming the intermediate layer and the outer layer is a material in which 1,8-diazabicyclo (5.4.0) undec-7-ene and a liquid epoxy resin are mixed, and the weight of the base resin is 0.5 to 5 Parts by weight of tackifier; A material in which nickel dibutyl dithiocarbamate and 2-mercapdobenzimidazole are mixed, 0.5 to 5 parts by weight of an antioxidant based on the weight of the base resin; And sorbitan monostearate, 0.5 to 5 parts by weight of the processing aid relative to the base resin weight; It is preferable to further include any one or two or more components selected. On the other hand, with respect to the numerical range for the content of the tackifier, if the lower limit is less than the improvement of the adhesive strength is not preferable, and if the upper limit is exceeded, the tackifier acts as a vulcanizing agent and the scorch phenomenon occurs Not preferred. In relation to the numerical range of the amount of the antioxidant used, it is not preferable because it is difficult to expect the effect of improving heat resistance when it is lower than the lower limit, and when the upper limit is exceeded, the excess amount acts as a foreign material, which lowers the mechanical properties. Can not do it. Regarding the use amount of the processing aid, it is not preferable because it is difficult to expect the effect of improving the workability when it falls below the lower limit, and when the upper limit is exceeded, it is not preferable because the excess amount acts as a foreign matter to lower the mechanical properties.

The rubber hose provided in the present invention according to the above is manufactured by the following method.

2 is a process flowchart for explaining a method for manufacturing a rubber hose according to the present invention. As shown in FIG. 2, first, a composition for preparing an inner layer, an intermediate layer, and an outer layer is prepared, and a rubber strip is prepared therefrom (S1), and then a tube having a two-layer structure in which the inner layer and the intermediate layer are laminated (S2). To prepare a braided layer surrounding the intermediate layer (S3), and finally forming the outer layer (S4) proceeds sequentially. Hereinafter, referring to FIG. 2, a process of sequentially divided into each step S1 to S4 will be described in more detail.

Rubber strip manufacturing step from the composition ( S1 )

The rubber hose according to the present invention is manufactured by using an extruder for rubber hoses. First, a fluororubber composition for preparing an inner layer, a silicone rubber composition for preparing an intermediate layer, and an outer layer are prepared. At this time, each prepared rubber composition is made into a strip (strip) of about 10 to 20 cm in width, 1 to 2 cm in thickness to be treated with a release agent so as not to adhere to each other, and then aged at room temperature for 24 hours or more. At this time, each composition used is preferably prepared in accordance with the above-described content with respect to the rubber hose provided in the present invention.

Tube manufacturing step of inner and middle layer bilayer structure ( S2 )

Of the composition components prepared according to the composition preparation step (S1), first, each strip (strip) prepared using the fluororubber composition for producing the inner layer and the silicone rubber composition for producing the intermediate layer is coextruded using a double extruder to A tube having a two-layer structure is produced. Regarding the extrusion conditions for forming the inner layer, the temperature of the extruder head is maintained at 80 to 110 ° C., the screw temperature is maintained at 50 to 80 ° C., and the screw speed is maintained at 5 to 40 RPM. On the other hand, with respect to the extrusion conditions for the formation of the intermediate layer, the temperature of the extruder head is maintained at 30 to 60 ℃, the screw temperature is maintained at 20 to 50 ℃, screw rotation speed is maintained at 5 to 40 RPM.

Braided layer  Forming step ( S3 )

A braided layer is formed using a reinforcing yarn to surround the middle layer of the tube having the extruded two-layer structure from the outside. This is to prevent the slip between the reinforcing yarns and to improve the pressure resistance.

Outer layer formation step ( S4 )

After the braided layer is formed using the braided irradiation, the rubber strip for preparing the outer layer is prepared in the same manner as the extrusion conditions for the intermediate layer.

When the extrusion from the inner layer to the outer layer is completed through the steps as described above, the release agent is applied to the inner surface of the circular hose prior to the crosslinking operation, and then inserted into a cylindrical metal mandrel having an outer diameter of 40 mm to maintain the shape. Let's do it. Thereafter, the pressure conditions are 2 to 10 atm, the crosslinking temperature is 120 to 180 ℃, the crosslinking time is subjected to steam crosslinking or continuous crosslinking under conditions of 10 minutes to 5 hours, and then the crosslinked rubber hose is extracted from the metal mandel To complete the hose manufacture.

Hereinafter, based on the rubber hose and the rubber hose manufacturing method provided by the present invention according to the above, it will be carried out as a specific content and tested to determine the technical effect of the present invention.

To the compositions prepared according to Examples (1 to 3) according to Table 1 and Comparative Examples (1 to 6) according to Table 2 below, base rubber was first introduced at room temperature using an open roll, followed by stabilizers and crosslinking. Formulation and other additives are added and fillers are added sequentially. Finally, the crosslinking agent is added. At this time, each of the substances were kneaded for a suitable time while being mixed to uniformly. After manufacturing in sheet state using this, press-molding at 160 ℃ for 30 minutes using an electric heating press, crosslinking at 150 ℃ for 120 minutes using a convection oven, and then cooled to room temperature to test the specimen for characteristics evaluation Prepared.

division Example (1-3) One 2 3 Epichlorohydrin rubber copolymer 100 100 100 O, O'-dibenzamidodiphenyldisulfide One One One Sorbitan monostearate 3 3 3 Nickel dibutyldithiocarbamate One One One 2-mercaptobenzimidazole - - 0.3 1,8-diazabicyclo (5.4.0) undec-7-ene One One One Liquid epoxy resin One 2 2 Furnace black (N550) 40 40 40 Silica 10 10 10 Stabilizer (hydrotalcite) 5 5 5 Ester plasticizer 15 15 15 N-N'-ethylene thiourea 1.5 1.5 1.5

division Comparative example (1-6) One 2 3 4 5 6 Epichlorohydrin rubber copolymer 100 100 100 100 100 100 O, O'-dibenzamidodiphenyldisulfide One One One One One One Sorbitan monostearate 3 3 3 3 3 3 Nickel dibutyldithiocarbamate One One One One One - 1,8-diazabicyclo (5.4.0) undec-7-ene One One One One One One Liquid epoxy resin - - - - - 2 Paraffin resin - - - - 3 - Furnace black (N550) 40 40 40 40 40 40 Silica 10 10 10 10 10 10 Stabilizer (hydrotalcite) - - 2.5 5 5 5 Stabilizer (MgO) - 5 2.5 - - - Stabilizer (Pb ₃ O ₄ ) 5 - - - - - Ester plasticizer 15 15 15 15 15 15 N-N'-ethylene thiourea 1.5 1.5 1.5 1.5 1.5 1.5

For each test specimen prepared using each of the compositions prepared according to Tables 1 and 2, the tensile test, aging test, oil resistance test and compressive permanent strain were measured and the results are shown in Table 3 below. It was.

The tensile test was evaluated according to the tensile test of Korean Industrial Standard KSM 6518 2-4, and the aging test was evaluated according to the aging test of Korean Industrial Standard KSM 6518 2-7. Temperature and time were tested under conditions of 72 hours at 120 ± 2 ° C, and the standard requirements for use as a vehicle fuel hose should be within ± 30% of tensile strength change and elongation change. The oil resistance test was evaluated according to the tensile test of Korean Industrial Standard KSM 6518-2-7. At this time, the temperature and time were tested under the conditions of 72 hours at 40 ± 2 ℃, the nasosolin characteristics were immersed in fuel oil B with a weight ratio of isooctane and toluene 7: 3, and the denatured gasoline characteristics are Lau The test was performed by immersing in fuel oil B having a weight ratio of isooctane and toluene added with 3% by weight of lauro peroxide (B) to 7: 3. Generally, the standard required for use as a fuel hose for a vehicle is that the tensile strength change rate and elongation rate change rate are within -30% of the gasoline resistance, and the gasoline resistance of the gasoline within -45%. Compressive permanent shrinkage test was evaluated according to the compressive permanent shrinkage test of Korea Industrial Standard KSM 6518 2-10. The temperature and time conditions at this time were made into 70 hours at 100 +/- 2 degreeC, and the test was done.

division Example (1-3) Comparative example (1-6) characteristic Evaluation item One 2 3 One 2 3 4 5 6 Room temperature characteristics Tensile Strength (㎏f / ㎠) 139 149 140 138 142 140 132 103 135 % Elongation 362 369 370 289 378 369 360 480 348 Heat resistance Tensile Strength Change Rate (%) -4 -2 -5 -3 -4 -5 -6 -2 -5 Elongation rate of change (%) -15 -13 -17 -20 -25 -24 -25 -33 -18 Solanol characteristics Tensile Strength Change Rate (%) -32 -28 -26 -26 -28 -28 -25 -28 -37 Elongation rate of change (%) -28 -26 -26 -26 -32 -30 -25 -30 -32 Altered Gasoline Properties Tensile Strength Change Rate (%) -35 -32 -33 -33 -48 -46 -42 -33 -42 Elongation rate of change (%) -38 -36 -34 -36 -37 -39 -46 -52 -47 Compressed Permanent Shrinkage (%) 30 29 28 7 36 30 35 33 31

As can be seen from Table 3, in the case of the embodiments (1 to 3), it is understood that the heat resistance, gasoline, and denatured gasoline properties required for use as a vehicle fuel hose are satisfied. Can be. In contrast, Comparative Example 1 satisfies the reference value required for a vehicle fuel hose in most items, but this is shown as a stabilizer, using lead tetraoxide (Pb ₂ O ₄ ) containing a banned heavy metal as a stabilizer. It is not desirable because it is the result. Comparative Example 2 is not preferable because the rate of change in tensile strength of the modified gasoline resistance is very low, which is due to the fact that the composition does not include a liquid epoxy resin having excellent chemical resistance and heat resistance. Comparative Examples 3 and 4 are not preferable because the tensile strength change rate of the modified gasoline resistance does not meet the required reference value, Comparative Examples 5 and 6 are not preferred because the elongation change rate of the modified gasoline resistance does not meet the required reference value.

Thus, it can be seen that in the vehicle fuel hose provided in the present invention, a product having high heat resistance and deterioration of gasoline resistance can be manufactured without using heavy metals.

Optimal embodiments of the present invention described above have been disclosed. Although specific terms have been used herein, they are used only for the purpose of describing the present invention in detail to those skilled in the art, and are not used to limit the scope of the present invention as defined in the meaning or claims.

According to the present invention, the epichlorohydrin composition forming the intermediate layer and the outer layer does not contain heavy metals and does not cause environmental problems. There is an advantage that can be used as a fuel hose.

Claims (11)

In the composition for the production of rubber fuel hose for vehicles, Base resin which is an epichlorohydrin type polymer; Filler, which is a single substance or a mixture of two or more selected from silica and carbon black; Hydrotalcite-based material, a stabilizer of 1 to 10 parts by weight based on the weight of the base resin; As the ester material, 10 to 30 parts by weight of a plasticizer relative to the weight of the base resin; And A thiourea-based material, 0.5 to 2 parts by weight of the crosslinking agent relative to the weight of the base resin; composition for manufacturing a rubber fuel hose for a vehicle, characterized in that it comprises. The method of claim 1, The epichlorohydrin-based polymer used as the base resin is a composition for producing a rubber fuel hose for a vehicle, characterized in that a mixture of two or three selected from epichlorohydrin, ethylene oxide and aryl glycidyl ether. The method of claim 1, Silica selected as the filler, 5 to 30 parts by weight based on the weight of the base resin composition for producing a rubber fuel hose for a vehicle. The method of claim 1, The carbon black selected as the filler is a furnace black, and the composition for producing a rubber fuel hose for a vehicle, characterized in that it comprises 20 to 80 parts by weight based on the weight of the base resin. The method of claim 1, The hydrotalcite-based material selected as the stabilizer is Mg _4.5 Al ₂ (OH) ₁₁ (CO ₃ ) _0.8 O _{2 A} composition for producing a rubber fuel hose for a vehicle. The method of claim 1, The thiourea-based material selected as the crosslinking agent included in the epichlorohydrin rubber composition constituting the intermediate layer is thiourea, ethylene thiourea, ethyl thiourea, butyl thiourea, diethylthiourea, thibutylthiourea, and trimethyl. A composition for manufacturing a rubber fuel hose for a vehicle, which is selected from any one or two or more materials selected from thiourea. The method according to any one of claims 1 to 6, The composition for manufacturing a vehicle rubber fuel hose, 1,8-diazabicyclo (5.4.0) undec-7-ene and a liquid epoxy resin mixed with 0.5 to 5 parts by weight of the tackifier based on the weight of the base resin; A material in which nickel dibutyl dithiocarbamate and 2-mercapdobenzimidazole are mixed, 0.5 to 5 parts by weight of an antioxidant based on the weight of the base resin; And As sorbitan monostearate, 0.5 to 5 parts by weight of the processing aid relative to the base resin weight; The rubber fuel hose manufacturing composition for a vehicle, characterized in that it further comprises any one or two or more components selected. An inner layer made of a fluororubber composition having a hollow interior and having an annular cross section; An intermediate layer made of the composition according to any one of claims 1 to 6 coated while covering the inner layer; Braided layer made of organic fibers coated while covering the intermediate layer; And A rubber fuel hose for a vehicle, comprising: an outer layer made of a composition according to any one of claims 1 to 6 coated while covering the braided layer. An inner layer made of a fluororubber composition having a hollow interior and having an annular cross section; An intermediate layer made of the composition according to any one of claims 1 to 6 coated while covering the inner layer; Braided layer made of organic fibers coated while covering the intermediate layer; And A rubber fuel hose for a vehicle, comprising: an outer layer made of a composition according to claim 7 coated on the braided layer. An inner layer made of a fluororubber composition having a hollow interior and having an annular cross section; An intermediate layer made of the composition according to claim 7 coated on the inner layer; Braided layer made of organic fibers coated while covering the intermediate layer; And A rubber fuel hose for a vehicle, comprising: an outer layer made of a composition according to any one of claims 1 to 6 coated while covering the braided layer. An inner layer made of a fluororubber composition having a hollow interior and having an annular cross section; An intermediate layer made of the composition according to claim 7 coated on the inner layer; Braided layer made of organic fibers coated while covering the intermediate layer; And A rubber fuel hose for a vehicle, comprising: an outer layer made of a composition according to claim 7 coated on the braided layer.

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