Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Staple length fiber
Patent
1998-09-17
2000-10-17
Weisberger, Richard
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Staple length fiber
428357, 428362, 428377, 428373, 428374, 428392, 428401, 264165, 26417211, 26417215, C08K 310
Patent
active
061328677
DESCRIPTION:
BRIEF SUMMARY
This invention relates to elongate gel-carrying articles (hereinafter "gel profiles") of various cross-sectional shapes, which may be useful in a wide variety of circumstances for sealing against and/or between surfaces. For avoidance of doubt, it is hereby confirmed that the claims to all articles of this invention relate to free-standing articles carrying the gel and are intended to exclude elongate components such as wires in a gel-containing cable or other assembly. Such components are in contact with the gel only as a result of being in that assembly and are therefore not free-standing gel profiles.
Our co-pending British Patent Application No. 9605927.4 filed on Mar. 21, 1996 and International Application No. PCT/GB96/02000 filed on Aug. 15, 1996 (RK533), from which the present application claims priority, describe profiles comprising an elongate filamentary carrier, one form of which carrier may be a multi-filament yarn, carrying an elongate body of gel which encloses at least 50%, preferably more than 75%, more preferably substantially all, of the perimeter of the carrier as viewed in transverse cross-section. The present invention is concerned with a specific form of carrier which has unexpectedly been found to provide greatly improved processing and appearance of the finished profiles.
The invention accordingly provides an article comprising a multi-filament yarn carrier carrying an elongate body of gel which encloses more than 50%, preferably more than 75%, more preferably substantially all, of the perimeter of the carrier as viewed in transverse cross-section, wherein the carrier is composed of synthetic polymeric material.
The carrier may comprise continuous filaments or one or more spun staple fibre yarns. One form of such carriers is the synthetic knitting yarn commonly known as "baby wool", a sample of which led to the present invention after being serendipitously (and indeed surreptitiously) extracted from the sewing box of the daughter of one of the inventors. The baby wool carrier comprises polyacrylonitrile and polyamide (preferably a nylon) spun from a co-mingled blend of polyacrylonitrile staple fibres and polyamide staple fibres. Trial of this small sample unexpectedly produced such a dramatic improvement in the processing and appearance of the resulting profile that further investigation was clearly warranted. This subsequently indicated a preferred form of the carriers for industrial manufacture of profiles according to the present invention comprising multi-filament polyester, preferably polyethylene terephthalate (PET), yarn in which the filaments are continuous.
Without limiting the invention to any specific theory, it is mentioned that the improved results of using the synthetic multi-filament carriers may be at least partly due to their relatively low retained surface moisture under ambient conditions. This may be less than 4%, preferably less than 3%, more preferably less than 2%, especially less than 1%, by weight, for example as determined by test method RAM10077. When gels are extruded thereon at temperatures typically in the range of 220-230.degree. C., the carriers of the present invention tend easily to receive uniform, homogeneous gel coatings, which are especially visually attractive when clear gels are used.
For such melt-coated profiles, it is preferred to use carriers made of materials whose softening temperatures are above the gel coating temperature. Thus, for gels applied at the above temperatures, fibres of polypropylene or polyacrylics or polyacrylonitriles (e.g. Dralon Trade Mark) alone, or in mixtures with softening-resistant fibres (e.g. wool) in too low proportions (e.g. 5% wool by weight), may have desirably low moisture content, but insufficiently high softening temperatures leading to unacceptable weakness and elongation during the coating process. These materials may, however, be useful with gels which are applicable at lower temperatures. The aforementioned baby wool survives the hotter extrusion process thanks to the presence of a sufficient proporti
REFERENCES:
patent: 4505222 (1985-03-01), Holt et al.
patent: 5665809 (1997-09-01), Wojtowicz
Search Report for International Application No. PCT/GB97/00775.
Search Report for British Application No. GB 9703380.7.
WPI Abstract Accession No. 94-172746 & JP 06113848 A (Teijin) 1994.
WPI Abstract Accession No. 74-61651V & DE 2307620 (Tokyo Boshi KK) 1974.
Bluck David
Hammond Philip James
Percy Michael John
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