High-pressure hoses in some fields of oilfield application require materials that withstand high temperature and aggressive medium. PA-11 and PVDF are widely used as liner of so called unbonded hoses and seem to be a good choice for bonded (i.e. rubber) hoses too due to their superior gas decompression resistance compared to rubber compounds. In case of rubber hoses adhesion between the thermoplastic liner and the rubber is a key parameter. The high chemical resistance of PA-11 and especially of PVDF is a disadvantageous property for establishing of the bond. Various rubber compounds containing specific bonding ingredients were tested to establish direct adhesion between rubbers and thermoplastics. Only few compounds have showed good adhesion, but the adhesion generally fell rapidly with increasing temperature. The other approach was the exploring of bonding agents for the surface treatment of the thermoplastics, in combination with modified compound. Lot of organic solvent based and water based bonding agents gave good adhesion properties to PA-11 but there are yet unsolved problems at PVDF surface. Metal-sprayed layers as a bonding agent can be used only in special conditions. All our results were interpreted from technological and production point of view. Phoenix Rubber Industrial Ltd. (by former name Taurus Emerge Ltd.) developed high pressure large bore hoses with plastic liner. The hoses are protected by patents among others in the UK and USA.
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