Pipes and tubular conduits – Flexible – Braided – interlaced – knitted or woven
Reexamination Certificate
1997-10-09
2001-01-30
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
Flexible
Braided, interlaced, knitted or woven
C138S126000, C138S137000, C138S141000, C428S516000
Reexamination Certificate
active
06179008
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a thermoplastic elastomer composition and a process for producing the same and a hose using a thermoplastic elastomer composition and a process for producing the same. More specifically, it relates to a hose which includes a thermoplastic copolyester elastomer and a specific acrylic rubber and which, when these are used as the inner tube and/or outer cover of the hose, is superior in oil resistance, flexibility, cold resistance, and heat resistance and is capable of being produced, without requiring a vulcanization step, a thermoplastic elastomer composition and a hose suitable for various types of sealing agents, and processes for producing the same.
The present invention further relates to an olefin thermoplastic elastomer composition which gives a good adhesion to polyester fiber and, in particular, has a bondability capable of withstanding a stress caused by repeated deformation particularly at a high temperature of 120° C. and a laminate having this as the adhesion layer or a structural layer, in particular a hose, and to a laminate superior in bonding formed by a layer of a thermoplastic elastomer composition composed of a polyolefin thermoplastic resin in which at least partially cross-linked elastomer component is blended and by a fiber reinforcing layer between which at least one thermoplastic adhesive resin selected from the group of maleic anhydride-modified polyolefin resin, epoxy-modified polyolefin resin, and polyester resin is interposed and which are bonded into an integral unit by hot melting and to a hose using the same.
The present invention further relates to a process for producing a hose composed of at least an inner tube composed of a thermoplastic material or flexible material and an outer cover composed of a thermoplastic material and a reinforcing layer, in particular relates to a process for producing a hose improved in durability of the hose by providing between the layers a bonding layer composed of a thermoplastic material and hot melting the bonding layer so as to form the bonding layer and reinforcing layer integrally and, in the production of a hose having at least an inner tube and a reinforcing layer composed of a reinforcing yarn, a hose braider provided with a heating means capable of improving the bondability of an inner tube composed at least at the outer circumference of the inner tube and the adhesive layer between reinforcing layers of a thermoplastic resin composition or thermoplastic elastomer composition or other thermoplastic resin material (hereinafter sometimes simply referred to as a thermoplastic resin material) with the reinforcing yarn braided on the outer circumference of the inner tube and the bondability of two or more reinforcing layers composed of reinforcing yarn and to manufacture a hose having flexibility and a high durability.
BACKGROUND ART
Rubber hoses are usually composed of an inner tube, a reinforcing layer, and an outer cover with the inner tube and outer cover composed of a vulcanized rubber. Such a rubber hose requires a vulcanization step, and therefore, there is the problem that the manufacturing process becomes complicated. On the other hand, there is known a so-called thermoplastic resin tube which is simpler in the manufacturing process thereof in the point that the inner tube and outer cover are composed of a thermoplastic resin and no vulcanization step is required. However, the thermoplastic resin comprising this resin hose is generally harder compared with vulcanized rubber, and therefore, it is difficult to obtain a flexible hose. In addition, the thermoplastic resin will soften by heating and therefore, it is usually difficult at a temperature of 120° C. or more.
Therefore, attempts have been made in the past to improve the flexibility by adding, to the thermoplastic resin, amorphous polymers such as a rubber (for example, see Japanese Unexamined Patent Publication (Kokai) No. 5-25374, Japanese Unexamined Patent Publication (Kokai) No. 6-64102, and Japanese Unexamined Patent Publication (Kokai) No. 6-207086), but there is the problem that the compatibility of the thermoplastic resin with rubber is poor and, if the blending amount of the rubber is increased to improve the flexibility in an acrylic rubber (ACM)/thermoplastic copolyester elastomer thermoplastic elastomer material, where the ACM composition is EA (ethyl acrylate)=40, BA (butyl acrylate)=32, MEA (methoxyethyl acrylate)=19, GMA (glycidyl methacrylate)=9 (wt %), the elongation will fall and, as a result, the breaking energy will be reduced and, in turn, the problem will arise of the hose performance falling.
Further, to improve the flexibility of a thermoplastic resin, there is known a resin hose comprised of a polyester thermoplastic elastomer having an inner tube of polybutylene terephthalate as a hard segment and polytetramethylene glycol or polycaprolactone as a soft segment, but this polyester thermoplastic elastomer is limited in the extent to which the hardness can be reduced to obtain the necessary heat softening resistance and strength properties. It is not possible to obtain a hose having a sufficient flexibility and heat resistance like that of a vulcanized rubber.
Therefore, development of a hose having sufficient flexibility which can be produced by a simple process not requiring a vulcanization step and a hose provided with heat resistance as well enabling use for transmission of pressure or transport of liquids at a high temperature has been desired. In response to this, there has been proposed a hose having an inner tube and an outer cover comprising a thermoplastic elastomer composed of a thermoplastic resin in which a vulcanized rubber (see Japanese Unexamined Patent Publication (Kokai) No. 6-64102) is dispersed.
This hose has an inner tube composed of a thermoplastic elastomer composition comprising a thermoplastic copolyester elastomer in which a vulcanized composition of at least one acrylic rubber having an acryl group and epoxy group is dispersed and has an outer cover composed of a thermoplastic elastomer composed of a thermoplastic resin in which a vulcanized rubber is dispersed. Further, the reinforcing layer is composed of a rayon fiber, polyester fiber, or hard steel wire or other organic fiber or inorganic wire such as stainless steel wire bonded with the inner tube and outer cover via an ordinary temperature-curing type urethane adhesive, etc.
By this configuration, it is possible to obtain a hose which is flexible at ordinary temperature and does not require a vulcanization step, but this hose is not necessarily satisfactory in terms of the low temperature properties, in particular, the flexibility at low temperature and cold resistance. Furthermore, the improvement in the oil resistance has been required.
Further, the high pressure resin hoses for use in construction machinery etc. should preferably be improved in abrasion resistance, heat softening resistance, flexibility, etc. In particular, there has been a strong need for the improvement in the abrasion resistance, resistance to heat softening resistance, flexibility, weather resistance, etc. of the outer cover of the hose. Furthermore, regarding the abrasion resistance, there is vibration and rocking in the environments where hoses are used, and therefore, the surface of the outer cover of the hose often rubs against adjacent metal members etc. and is abraded. In the past, an ether based polyurethane or other thermoplastic resin having abrasion resistance was used for the outer cover of such a hose, but this was insufficient for long term use. Therefore, studies have been made how to improve the problem by the polymer structure, but there have been the defects of impairment of the flexibility. In this way, up until now, there has not been a thermoplastic elastomer composition which is superior in abrasion resistance, heat softening resistance, flexibility, etc. and can be suitably used for the outer cover of a hose.
In the past, in the bonding of an olefin thermoplastic elast
Hatanaka Susumu
Irii Daisuke
Ishikawa Kazunori
Kawazura Tetsuji
Kuroda Noriaki
Brinson Patrick
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
The Yokohama Rubber Co. Ltd.
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