Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-09-12
2003-04-01
Dixon, Merrick (Department: 1774)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S285000, C156S177000, C156S277000, C156S384000, C264S510000, C264S900000
Reexamination Certificate
active
06540867
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to certain novel composite materials and products made therefrom.
The composites and products of the invention are preferably prepared using the disclosure and teachings of my copending U.S. application Ser. No. 08/236,258, the entire contents of which are incorporated herein by reference. Said application makes reference to an article by Chou et al. entitled “Composites” appearing in
Scientific American
, October, 1986, Volume 255, No. 4, pages 192-203. This article, which includes an extensive discussion regarding composites comprising fibrous materials dispersed in various matrix materials, is also incorporated herein by reference. This article has a tacit assumption, consistent with industry thrust for some decades that designers/engineers of composites strive for high fiber-matrix bond levels. Ser. No. 08/236,258 teaches benefit from weak bond levels, soft, pliant, flexible resilient composites.
In Ser. No. 08/236,258, I have disclosed a composite material which comprises a polyurethane matrix reinforced with a fibrous material, e.g. one or more plies of fabric with a polyurethane matrix polymerized in situ, which is made by wetting the fibrous material with liquid polyurethane-forming reactants and allowing these to react at a temperature below the melting point of the fibrous material. The reaction results in the formation of a solid polymeric matrix as cure takes place. The rate of cure can be either accelerated by catalysts and heat or retarded by adding other chemicals or evacuating heat.
The present invention contemplates certain modifications in the product and process of Ser. No. 236,258 to enable the production of composite articles having a variety of properties as desired, for example, improved toughness, and the facility of producing three-dimensional products, cosmetic permanence, control of flexibility, control of grip, visual texture and barrier properties. Typical products contemplated by the invention include such varied articles as shoe outsoles, suitcases, furniture components, hoses, ducts, luggage, flags, awnings, the soft parts of umbrellas, decorated narrow tapes/straps, labels, helmets, seating, gloves, footwear, small boats, protective apparel and resilient floor and wall coverings or the like where such property combinations as flexibility, toughness, cosmetic variations and permanence, and breathability/fluid barriers are desired.
Broadly described, a product according to the invention comprises:
(1) a composite as in, for example, Ser. No. 08/236,258, comprising a solid polyurethane matrix surrounding a fibrous reinforcing material where the matrix is formed in situ by reaction of liquid matrix-forming materials about the fibrous material; and
(2) a thermoplastic polymer film or the equivalent on one or both sides of the composite (1), the film being bound to the composite by adhesion to the polyurethane matrix, the adhesion being the result of physical and/or chemical reaction which occurs or is enhanced as the liquid matrix material cures to form the solid matrix.
The present products can be prepared in a variety of ways, for example, by placing one or more layers of the fibrous material on a flat or curved surface, over a male mold or across the cavity of a female mold or between the parts of a mating mold, wetting the layer(s) with a mixture of the polyurethane-forming reactants, placing the thermoplastic polymer film or its equivalent on the wetted layer(s) before any significant reaction occurs, causing the plies of the resulting layup to consolidate as desired and to take the shape of the mold as and when necessary and allowing the polyurethane-forming reaction to take place. This yields a flat or molded product with the polymer film adhesively bound to the polyurethane matrix.
The process as described above can be varied in numerous ways. For example, the layer(s) of fibrous material can be laminated to polymeric film prior to placing a layup containing such laminate on a mold or wetting it with the metered and mixed liquid parts from which a solid matrix will form in place on at least one surface of the film as well as on, around and among the fibers of the fibrous material.
The layers or plies of fibrous material may be wet while they are in place on a solid base or mold. Alternatively, they may be wet out before placing them on a base or mold, such as by passing them through a nip with the metered and mixed co-reactive parts present.
Wet and dry plies of fibrous material may be used in the same layup, with the dry plies becoming partially or thoroughly wet out by virtue of contact with wet plies and consolidation of the plies.
It is also possible to prepare a product comprising multiple alternate layers of the reinforced matrix and polymer film by building up a repeated series of wetted layers of fibrous material followed by polymer film, wetted layers, polymer film and so on to the desired thickness level provided successive plies are consolidated suitably before any significant polyurethane formation occurs.
The fibrous material is preferably in the form of a knitted, stitch-bonded, woven, braided or non-woven fabric although fibers, filaments or yarns per se may also be used. Fabrics are, however, preferred as these facilitate wetting out and laying up of plies of fibers with the urethane-forming reactants prior to their positioning adjacent to one or more films. Typically, a plurality of fabric layers or plies are brought together, these plies are wet with the reactants, the polymer film is placed against the wetted plies and the process repeated as many times as desired before the polyurethane reaction is significantly underway.
The fibrous material may be of any available or engineered configuration or composition provided it has a melting point above the temperature of the polyurethane reaction. Typically, for example, the fibrous material comprises polyester, polyethylene, polypropylene, polyaramid, and/or like materials which do not harbor significant moisture but do have a significant quantity of reactive sites for the urethane-forming reactants. Mineral (typically with a bond promoter such as silane), animal, vegetable (including man-made cellulosics), nylon, acrylic, and like fibrous materials may be used in certain circumstances where higher levels of fiber-matrix bonding are desirable or where a cure is aided by moisture, such as a moisture-curing urethane.
The thermoplastic polymer film may also be of any desired composition, e.g. polyester, polyvinyl chloride or floride, polycarbonate, nylon, or polyurethane. Particularly desirable results are obtained when using polyurethane film having OH groups that can react with the polyurethane matrix parts as the matrix is being formed to provide improved bonding. Polyurethane films, typically thermoplastic polyurethane films, are available for use with such desirable properties as toughness, elasticity, clarity (including clarity after stretch or stretch/recovery), colorability (including good resolution of print thereon), barrier properties (permeability or resistance to passage of various categories of fluids), light stability, and chemical reactivity. The films which are used may be colored, printed, clear, smooth, textured, or perforated/pin-holed films. The thickness of such films can be widely varied and will depend on the product desired. A typical example is polyurethane film of two mils to 100 mils thickness, although it will be appreciated that other types of films and thickness can be used.
As indicated, the film may be clear (transparent) or it may be colored or carry a design, printing, texture, embossing, topography or the like on its surface. In one embodiment of the invention, a fabric layer within the matrix may be provided with a color, print or design so that if the polyurethane matrix and polymer film are transparent, the color, print or design will show through while being protected by the polymer film from wear, abrasion, sunlight or the like.
In another embodiment, the film itself may carry colo
Dixon Merrick
Morgan & Lewis & Bockius, LLP
Randemo, Inc.
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