Patent Application
20080053597
With respect to the drawings,
Typically, the inner layer of the tubular structure is an elastomeric or rubber material such as a nitrile or chlorinated polyolefin, e.g., chlorinated polyethylene. While other conventional elastomeric materials may be used if desired, the inner layer, preferably, is either an acrylonitrile-butadiene polymer or a chlorinated polyethylene. Where a chlorinated polyethylene is employed in the tubular structure of the present invention, an adhesive material may be advantageously applied between the chlorinated polyethylene layer and the fluoropolymer layer.
The barrier layer of the tubular structure is a fluoropolymer that prevents or reduces the permeation of fuel, chemical and vapor through the barrier layer. Typically, the barrier layer is a fluoropolymer containing polymerized units of tetrafluoroethylene, hexafluoropropylkene and vinylidene fluoride. Preferably, the fluoropolymer is a tetrafluoroethylene-hexafluoropropylene-vinylidene terpolymer (THV); a fluoroquad polymer derived from (i) tetrafluoroethylene (ii)hexafluoropropylene (iii) vinylidene fluoride and (iv) a perfluorovinyl ether; or a blend of about 20 to 80 weight percent of a first fluorointerpolymer having a fluorine content of about 65 to 73 weight percent with about 80 to 20 weight percent of a second fluorointerpolymer having a fluorine content of about 70 to 75 weight percent, wherein said first fluorointerpolymer is a copolymer or terpolymer formed by the copolymerization of two or more monomers selected from the group consisting of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, and said second fluoropolymer is a terpolymer formed by the copolymerization of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, wherein said first fluorointerpolymer exhibits elastomeric characteristics and said second fluorointerpolymer exhibits thermoplastic characteristics. Such fluoropolymer blends are more fully described in U.S. Pat. No. 6,203,873, the contents of which is incorporated herein by reference thereto.
The reinforcement materials useful in the present invention are materials which afford physical strength to the finished hose. Typically, the reinforcement member is a plurality of synthetic or natural fibers selected from the group consisting of glass fibers, cotton fibers, polyamide fibers, polyester fibers, rayon fibers and the like. Preferably, the reinforcement material is an aromatic polyamide such as Kevlar or Nomex, both of which are manufactured by DuPont. The reinforcing materials may be knitted, braided or spiraled to form the reinforcement member. In a preferred aspect of the invention, the reinforcing material is spiraled. While the reinforcement member may be a preferred component of the present hose structure, it is not critical in every application. Therefore, the reinforcement member may or may not be used in the manufacture of certain hoses depending on the requirements of the manufacturer.
Typically, the inner layer of the tubular structure contains a conductive material such as metal or carbon. Preferably, the conductive material is carbon in the form of carbon black, but may be any conductive agent or combination of conducting agents commonly recognized in the industry to provide conductivity to a rubber or plastic material. Examples of such conductive agents include elemental carbon in the form of carbon black and carbon fibrils, metals such as copper, silver, gold, nickel, and alloys or mixtures of such metals. The use of such conductive agents is known in the art to dissipate static electricity in the transportation of a fluid through the tubular structure. Non-conducting elastomeric polymer materials may be employed as the inner layer in applications where dissipation of static electricity is not required.
The outer cover is a protective layer of any of the commercially recognized materials for such use such as elastomers, thermoplastic polymers, thermosetting polymers, and the like. Typically, the protective cover layer is a synthetic elastomer having good heat resistance, oil resistance, weather resistance and flame resistance. Preferably, the outer cover layer is a synthetic elastomer selected from the group consisting of styrene-butadiene rubber (SBR); butadiene-nitrile rubber such as butadiene-acrylonitrile rubber, chlorinated polyethylene, chlorosulfonated polyethylene, vinylethylene-acrylic rubber, acrylic rubber, epichlorohydrin, e.g., Hydrin 200, a copolymer of epichlorohydrin and ethylene oxide available from DuPont, polychloroprene rubber (CR), polyvinyl chloride, ethylene-propylene copolymers (EPM), ethylene-propylene-diene terpolymer (EPDM), ultra high molecular weight polyethylene (UHMWPE), high density polyethylene (HDPE), and blends thereof. Preferably, the cover layer is chlorinated polyethylene.
In accordance with the present invention, an adhesive material is typically employed between the chlorinated polyethylene inner tubular structure and the fluoropolymer barrier layer and between the fluoropolymer barrier layer and the chlorinated polyethylene backing layer or outer cover layer of the hose in order to prevent or reduce the likelihood of the layers separating during use.
Other additives such as antioxidants, fillers, plasticizers, metal oxides/hydroxides, processing aids, crosslinking agents, co-agents etc. may be employed in amounts and methods known in the art to provide their desired effects.
The tubular structures of the present invention are formed by known methods such as extruding the various layers using simultaneous, extrusion, tandum extrusion, or coextrusion. Typically, the hose of the present invention are produced by separate or tandum extrusion for versatility and economic reasons.
Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent to those skilled in the art that modifications and variations are possible without departing from the scope of the invention as defined in the appended claims.
This application is a continuation-in-part of U.S. patent application Ser. No. 11/513,371, filed Aug. 30, 2006.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11513371 | Aug 2006 | US |
| Child | 11711699 | US |
