Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Coating produced by extrusion
Reexamination Certificate
1999-03-24
2001-05-22
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Coated or impregnated woven, knit, or nonwoven fabric which...
Coating produced by extrusion
C442S076000, C442S286000, C442S290000, C442S394000, C442S398000
Reexamination Certificate
active
06235658
ABSTRACT:
The invention relates to composites with a textile character, which have a high water vapor permeability and a high waterproofness and consist of textile fabrics, a film coating and/or an extrusion coating of polyolefins and optionally a layer of bonding agent between the textile fabric and the film coating and/or extrusion coating. The composites are suitable for use in the hygiene sector, in the medical area, in the textile and clothing industry, in the automobile industry, as well as in construction.
The manufacture of textile fabrics in the form of synthetic nonwovens according to the staple fiber technology, the spin bonding technology and the melt blow technology (Fourne, F., Chemiefasern/Textilindustrie 81 (1979), 445-449; 95 (1993), 811-822, German patents 195 21 466 and 19 620 379) as well as the afterstretching of synthetic nonwovens (German patents 195 01 123 and 195 01 125), are well known.
Equally well-known is the application of extrusion coatings of polyolefins, such as polypropylene (WO 96/09 165; French patent 22 30 830), polyethylene (German patent 40 16 348, U.S. Pat. No. 4,221,692) or ethylene copolymers (French patent 27 15 948) on textile fabrics of woven, knitted and nonwoven fabrics of polyethylene, polypropylene, polyamide, polyethylene terephthalate, cotton or cellulose.
The coating of textile fabrics with polypropylene has the disadvantage that constrictions, transversely to the pull-off direction, occur already at average coating speeds and express themselves in a fluctuating width and thickness of the coating. It is known that this problem during the coating of textile fabrics can be solved by using mixtures of polypropylene and polyethylene (European patent 0 283 201, Japanese patent 03185185) or ethylene copolymers (U.S. Pat. No. 4,255,323).
Furthermore, it is known that film coatings of polypropylene can be applied on textile fabrics by thermal bonding (WO 95/11803; German patents 19 534 704 and 19 534 702) or by welding using ultrasound (European patent 0 505 027).
Polypropylenes, to which acid or acid anhydride groups are grafted, ethylene (meth)acrylate copolymers, EVA copolymers, polyisocyanates or polyurethanes are known bonding agents for intermediate layers of bonding agents to improve the adhesion of polypropylene coating to the textile fabric (Japanese patents 52094383 and 60250938).
Solutions are known for the problem of producing textile fabrics with a high water vapor permeability and a high waterproofness.
Thermally bonded nonwovens of spun bonded and nonwoven materials, which have been produced by the melt blowing method (European patent 0 814 190), or multicomponent composites of textile fabrics, permeable to water vapor, and adhesive layers, which do not permit water to permeate but are permeable to water vapor (German patent 39 22 028), are described for use as sheets stretched under roofs or as sanitary napkins.
Composites of high waterproofness, which are permeable to water vapor, are also obtained by thermally bonding fiber layers with films having rubberlike elasticity (German patent 42 43 012).
Likewise, fabrics with good breathing properties are known, which consist of an impermeable middle layer of polyvinyl alcohol film and two porous nonwovens of polypropylene as outer layers (U.S. Pat. No. 4,828,556), or of a water vapor-permeable middle layer of thermoplastic polyurethane and outer layers of thermoplastic nonwovens and micro-porous polymer membranes (WO 91/12132), or of a porous polypropylene middle layer and outer layers of spun bonded polypropylene (European patent 0 505 027).
For diapers and sanitary napkins, two-component composites are described, which consist of fine fiber nonwovens and conventional fiber nonwovens (German patent 41 08 037 and 39 17 791) or of absorbents of polypropylene woven fabrics, polypropylene nonwovens and viscose staple fibers, which are coated with polyolefins (German patent 35 15 580).
It is furthermore known that fabrics, which are highly permeable to water vapor and very inpermeable to water, can be produced by producing &bgr;-nucleated polypropylene films with addition of &bgr;-nucleating agents, such as quinacridone or metal salts of dicarboxylic acids, extracting the &bgr;-nucleated polypropylene portion from the film and, optionally, stretching the film (European patent 0 418 369; U.S. Pat. No. 5,208,098, German patent 36 10 644).
Finally, the manufacture of fabrics, which are highly permeable to water vapor and very impermeable to water, by stretching polyolefin films of polyethylene or polypropylene, which contain a high proportion of fillers, is known (European patents 0 352 802 and 0 779 325).
The disadvantages of the known solutions for producing composites with a textile character with a high water vapor permeability and high waterproofness consist therein that either the textile properties of the composites are unsatisfactory, the manufacture of the composites is problematic or technologically expensive, or the composites are not sufficiently waterproof.
It was an object of the present invention to develop composites with a textile character, which are highly permeable to water vapor and very waterproof and consist of fabrics, which are based on polypropylene and optionally an intermediate layer of adhesive.
The inventive object was accomplished by composites with a textile character, which have a water vapor permeability of more than 1,000 g/m
2
/24 h and preferably of more than 1,800 g/m
2
/24 h, and a waterproofness of more than 500 mm of water column mm and preferably of more than 750 of water column and consist of A) textile fabrics, B) film coatings and/or extrusion coatings and optionally C) of an intermediate layer of bonding agent between the textile fabric and the film coating and/or the extrusion coating,
A) the textile fabrics representing woven, knitted or nonwoven fabrics based on polyethylene, polypropylenes, polyethylene terephthalate, polyamide, cellulose or cotton,
B) the film coatings and/or extrusion coatings having a thickness of 3 to 200 &mgr;m and preferably of 5 to 70 &mgr;m and consisting of polypropylenes with the addition of 0.01 to 2.5% by weight of stabilizers, 0.01 to 1% by weight of processing aids, in each case based on the sum of the polypropylenes, and optionally 0.1 to 1% by weight of antistats, 0.2 to 3% by weight of pigments, 2 to 20% by weight of flame retardants and/or 0.05 to 1% by weight of nucleating agents, in each case based on the sum of the polypropylenes, as auxiliary materials, and/or 10 to 70% by weight and preferably 20 to 50% by weight, based on the sum of the polypropylenes, of inorganic and/or organic fillers and/or reinforcing materials, and
C) the intermediate layer of bonding agent between the textile fabric and the film coating and/or extrusion coating having a thickness of 0.5 to 20 &mgr;m and preferably of 1 to 10 &mgr;m and consisting of polar olefin copolymers and/or olefin grafted copolymers, such as EVA copolymers, ethylene/acrylic acid copolymers, ethylene/methyl acrylate copolymers or polyethylene or polypropylenes grafted with unsaturated carboxylic acids or carboxylic acid anhydrides,
pursuant to the invention, the polypropylenes of the film coatings and/or extrusion coatings B) either being polypropylene mixtures, which consist on the one hand of
B1) 1 to 50% by weight and preferably 5 to 30% by weight of modified propylene polymers with melt indexes of 0.1 to 50 g/10 min at 230° C./2.16 kg and preferably of 1 to 40 g/10 min at 230° C./2.16 kg and a ratio of the intrinsic viscosity of the modified polypropylene to the intrinsic viscosity of the unmodified polypropylenes with largely the same weight average molecular weight of 0.20 to 0.95, and, on the other, of
B2) 50 to 99% by weight and preferably of 70 to 95% by weight of
b2.1) propylene polymers, preferably propylene homopolymers, prepared using Ziegler-Natta catalysts or metallocene catalysts, and/or copolymers of propylene, ethylene and/or &agr;-olefins with 4 to 18 carbon atoms with a propylene content of 80.0 to 99.9% by weight in the form of rand
Kirchberger Manfred
Panzer Ulf
Paulik Christian
Wolfsberger Anton
Borealis GmbH
Jordan and Hamburg LLP
Morris Terrel
Torres Norca L.
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