Title:
METHOD FOR MANUFACTURING REINFORCED PLASTIC TUBE AND SHEETING
Document Type and Number:
WIPO Patent Application WO1995004644
Kind Code:
A3
Abstract:
Method for manufacturing a plastic tube provided with a wound reinforcement (2), in which one or more reinforcement layers (2) are wound around an extruded inner tube (1) made of thermoplastic material and an outer casing (4) is extruded around the layers; characterized in that for the reinforcement, material with a relatively high dielectric loss factor is chosen, the reinforcement layers are wound onto the inner tube at ambient temperature, the outer casing is extruded in direct contact with the outermost reinforcement layer, but is not joined to it, and the entire combination is subjected to a treatment with an electric field having a frequency in the radiowave (RF) or microwave (MW) band for a period which, as a result of the dielectric heating of the reinforcement material thereby occurring, is sufficient to take the thermoplastic material to welding temperature in the zones directly adjoining the reinforcement material, so that the two parts are welded together. Method for manufacturing flat, internally reinforced sheets of thermoplastic material, in which a tubular product is manufactured first in the manner indicated above, and after the step of treatment with the RF field, the tube obtained is cut through in the lengthwise direction and is then laid out flat.
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Inventors:
KIEFT HENDRIK HERMANNUS (NL)
Application Number:
PCT/NL1994/000182
Publication Date:
March 16, 1995
Filing Date:
August 04, 1994
Export Citation:
Assignee:
WAVIN BV (NL)
KIEFT HENDRIK HERMANNUS (NL)
KIEFT HENDRIK HERMANNUS (NL)
International Classes:
B29C35/10; B29C48/09; B29C48/153; B29C65/04; B29C65/36; B29C69/00; B29C70/08; B29D23/00; F16L11/08; B29C35/08; B29C48/10; B29C48/21; B29C53/56; (IPC1-7): B29C47/02; B29C35/14; B29C65/04
Domestic Patent References:
| WO1992001885A1 | 1992-02-06 |
Foreign References:
| US4219522A | 1980-08-26 | |||
| DE1927042A1 | 1970-08-13 | |||
| US3769127A | 1973-10-30 |
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