GB2044880A

GB2044880A - Fuel hose

Info

Publication number: GB2044880A
Application number: GB8006397A
Authority: GB
Original assignee: Goodyear Tire and Rubber Co
Current assignee: Goodyear Tire and Rubber Co
Priority date: 1979-03-19
Filing date: 1980-02-26
Publication date: 1980-10-22
Also published as: CA1146479A; JPS55124646A; BR8001395A; ZA80925B; IT1130977B; AU5556480A; FR2451824A1; AU533409B2; FR2451824B1; DE3009866C2; JPS5938888B2; DE3009866A1; GB2044880B; IT8020705A0

Abstract

A fuel hose having at least one inner layer of a nitrile rubber containing a built in antioxidant-antiozonant and a covering of chlorosulfonated polyethylene. The inner layer(s) is formed by a terpolymer of butadiene, acrylonitrile and N(4-anilinophenyl) methacrylamide or acrylamide. The inner layer(s) may be provided with braided or spiral fabric or filament wrapped reinforcement. The acrylonitrile content may comprise 22-38%. <IMAGE>

Description

SPECIFICATION Improved fuel hose Technical Field This invention relates to improved high performance fuel hose and to the method of manufacture.

Background Art The Automotive Industry has expressed concern that fuel hose performance must be improved to withstand highly aromatic fuels, sour gasoline exposure, fuel permeation loss, and more rigorous service conditions. For example, the conventional nitrile rubber fuel hose tubes which are carbon black filled have heat aging properties limited to 70 hours at 100 C. and the new General Motors specification calls for more severe test standards.

Disclosure and Practice of the Invention The improved hose of this invention extends the heat aging to 720 hours, and preferably 1000 hours at 1 25' C., reduces the fuel extracted methanol insolubles and achieves - 40"C.

performance originally and also after oil and fuel exposure. Retention of these advantages with optimized balance of fuel permeation loss and low temperature flex is achieved with an acrylonitrile/butadiene bound antioxidant nitrile rubber inner tube having a covering of a compounded chlorosulfonated polyethylene.

The hose of this invention is composed of a bound antioxidant nitrile rubber fuel resistant tube or at least one layer thereof with or without braided or spiral fabric or filament wrapped reinforcement and covered with a heat and ozone resistant jacket compound such as chlorosulfonated polyethylene, or other suitable material. A bound antioxidant nitrile polymer with an acrylonitrile content from 22 to 32 percent can be used to achieve - 40"C. flex performance, with 28 to 30 percent being preferred. A bound antioxidant nitrile rubber with an acrylonitrile content from 32 to 43 percent gives better resistance to fuel permeation loss, with a 34 to 38 percent acrylonitrile polymer being preferred for an optimized balance of permeation resistance and low temperature flex.

This bound antioxidant-antiozonant nitrile rubber, compounded predominantly with mineral fillers with only sufficient carbon black for coloring purposes and plasticized with plasticizer selected for its contribution to heat resistance, low temperature flex and lack of fuel extracted methanol insolubles, is preferred. Added conventional antioxidants if used are selected for their compatability with the bound antioxidant system. Lubricants and processing aids preferably are low in their contribution to fuel insolubles. A cure system with sulfur donating accelerators, little or no free sulfur, and zinc oxide activation is preferred for long term heat resistance.

The term "bound antioxidant nitrile rubber" is used to designate the well known terpolymers prepared from butadiene, acrylonitrile and N(4-anilinophenyl) methacrylamide or acrylamide and is available as Chemigum HR-765 nitrile rubber.

The chlorosulfonated polyethylenes are well known and available as Hypalon, a du Pont trademark. The chlorosulfonated polyethylene (100 parts basis) is compounded with about 25 to 125 parts of filler, 3 to 8 parts of magnesium oxide, 3 to 9 parts of hydrocarbon plasticizer and 0.5 to 4 parts of sulfur type accelerator and the resulting compounded chlorosulfonated polyethylene is useful as the covering for the hose.

The nature of this invention can be more readily seen and understood by reference to the following representative examples where all parts and percentages are by weight unless otherwise indicated.

EXAMPLE A typical bound antioxidant nitrile rubber compounded for use to extrude a tube for construction of a hose is as follows: Ingredients Parts Chemigum HR-765 100.0 Stearate Coated Talc 40.0 Finely Divided Silica, 55.0 Mixture of 3, 5 and 10 to 20 microns Polyethylene 1.0 Antioxidant Amine Type 4.0 A Liquid Plasticizer (Resinous Type) 20.0 Carbon Black 5.0 Stearic Acid 0.5 Zinc Oxide 5.0 Silane 1.0 Mineral Oil Dispersion of MgO 10.0 Usually the materbatch (100) is mixed with 1.2 parts of a rubber accelerator of sulfur type and 1.2 parts of sulfenamide type accelerator and a small amount of a scorch retarder such as dithiomorpholine to give a curative mix.

The above curative mix was charged to an extruder and extruded as a tube. This tube was then covered with 0.5 to 1 centimeter of a compounded chlorosulfonated polyethylene, available under the trade name HypalonTM. Then the covered tube was cured at 163 C. for 25 minutes to yield the improved hose. This hose exhibited improved service life at 125 C in a circulating air oven relative to customary hose having a nitrile rubber tube and a chlorosulfonated polyethylene cover. Also, this new hose exhibited improved resistance to methanol extractables and improved - 40" C. properties.

A Typical Compounded Chlorosulfonated Polyethylene Useful for Outer Hose Covering Polymer Type Parts Chlorosulfonated polyethylene 100.0 Ethylene-propylene-diene terpolymer 3.0 Polyethylene 5.0 MT Carbon black 50.0 Natural ground calcium carbonate 50.0 Aromatic hydrocarbon resin 5.0 Nickel dibutyldithiocarbamate 1.0 Polyethylene lubricant 2.0 Magnesium oxide 5.0 N,N7-m-phenylenedimaleimide 1.0 Benzothiazyl disulfide 1.0 Dipentamethylene thiuram 1.0 234.0 In an alternate embodiment the extruded bound antioxidant nitrile rubber tube is wrapped with a reinforcing member such as a nylon or polyester fabric or filament before being covered with the coating of chlorosulfonated polyethylene. This reinforced hose especially is desirable where pressurized systems are needed.

While certain representative embodiments and details have been shown for the purpose of illustrating the invention it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

Claims

1. An improved hose composed of at least one inner layer of bound antiozonant nitrile rubber and an outer cover of a chlorosulfonated polyethylene.

2. The hose of Claim 1 wherein the hose contains reinforcing members.

3. The hose of Claim 1 wherein the nitrile rubber contains butadiene and 22 to 43 percent acrylonitrile.