Patent Description:
Flexible-composite materials are widely used in applications requiring both mechanical flexibility and high strength-to-weight ratios. Although flexible-composite materials may be considered a specialized subset of the larger body composite-materials, their importance in many specific areas of technology is significant.

As the term suggests, composite materials combine two or more constituent materials to form a unified material composition. An example of a flexible composite material would be a polymer matrix embedding an arrangement of flexible fibers.

Utilization of flexible-composite materials is envisioned in many technical fields ranging from simple consumer products to advanced aerospace applications. Thus, a system for quickly and economically producing high-quality flexible-composite materials would be of benefit to many.

<CIT> relates to a non- woven composite material comprising at least one waterproof breathable (W/B) membrane, a first unidirectional non- woven composite layer having multiple fibers enclosed by adhesive in parallel to each other, a second unidirectional nonwoven composite layer having multiple fibers enclosed in adhesive in parallel to each other.

<CIT> discloses sail materials comprised of several layers of unidirectional fibers. The monofilaments are uniformly embedded in a matrix.

<CIT> discloses a sheet material with an anti-skid surface, suitable for use as a roofing underlayment or wrapper, comprising a scrim made of woven plastic tapes with monofilaments that are round in cross section and have a diameter larger than the thickness of the plastic tapes interwoven with the tapes. The monofilaments form ridges on the sheet material that impart an enhanced coefficient of friction to it. The monofilaments may be incorporated in the weave in the warp or weft directions or both.

<CIT> relates to a moulding material comprising a fibrous reinforcement layer and a curable resin matrix. The fibrous reinforcement layer comprises a non-woven fabric comprising a single layer of unidirectional tows arranged at an angle greater than <NUM> degrees in relation to the lengthwise direction of the fabric and a support structure for maintaining the arrangement of the tows.

Various embodiments of the present disclosure generally comprise flexible-composite materials that include scrim reinforcement. A composite material contains one or more unidirectional fiber-reinforced layers each having thinly spread parallel fibers coated with adhesive (these layers are termed unitapes). In accordance with one aspect of the present invention, the thin unitape layers can be manufactured using fiber bundles consisting of a plurality of monofilaments that are combined with a polymer resin and pultruded through a rotary die such that the monofilaments are spread and oriented parallel to each other. In accordance with another aspect, the composite material includes a woven or non-woven reinforcement laid scrim. Laid scrim is a lower cost reinforcing fabric made from continuous filament yarn in an open mesh construction. The laid scrim manufacturing process chemically bonds non-woven yarns together, enhancing the scrim with unique characteristics. The laid scrim is a cost effective way to add fiber reinforcement to a composite material especially in bias orientations (for example, about +/-<NUM>°, +/-<NUM>°, +/-<NUM>°) because the added processing steps to add unitape bias plies are skipped and replaced by inserting a pre-manufactured scrim. The laid scrim may be pre-coated with adhesive, pre-laminated to supporting films, or it may be necessary to sandwich it between unitape layers to glue it in place.

The present invention comprises flexible-composite materials comprising at least one scrim reinforcement. Thin unitape layers are manufactured using fiber bundles consisting of a plurality of monofilaments that are combined with a polymer resin and pultruded through a rotary die such that the monofilaments are spread and oriented parallel to each other. The key feature of this embodiment is that the fibers that make up the unitape are spread and either the distance between fibers is gapped such that an adhesive-free and fiber-free space between each group of monofilaments is formed, or fiber tows are removed after the monofilaments have been spread resulting in a similarly gapped unitape. A scrim is formed by bonding two or more of these unitape layers together. Additional films, membranes, fabrics, random oriented non-wovens, oriented non-wovens, scrims, or coatings may be applied to the outer surfaces or layered within this composite material.

Various embodiments include a reinforcement type that is a random oriented non-woven, or oriented non-woven constructed from engineering fibers such as, but are not limited to, UHMWPE (e.g. Spectra®, Dyneema®), aramids (e.g. Kevlar®), liquid crystal polymers (e.g. Vectran®), carbon fiber of various grades, PBO (e.g. Zylon®), nylon, polyester (Rayon), PEN, Nomex and other fire proof, high temperature fibers, steel or other metal fibers, and combinations thereof. This reinforcement layer may be bonded, fused, impregnated, extruded or coated to combine the reinforcement with a monolithic film (PET, Nylon, ECTFE, urethane, etc.), breathable membranes (Teflon, urethane, microporous, etc.), solvent or waterbased dispersion, woven or non-woven fabrics, leather, unidirectional tape, or other layers.

In various embodiments, the present disclosure encompasses a method of manufacturing a flexible-composite material, said method comprising providing at least one scrim layer and bonding at least one woven fabric, non-woven fabric, and/or membrane layer onto said at least one scrim layer. In various embodiments, the scrim layer comprises at least two unidirectional tape layers further comprising a plurality of parallel fiber bundles comprising monofilaments in an adhesive resin, wherein the fiber bundles are separated by gaps. In various embodiments, the scrim layer comprises a commercially available woven or non-woven reinforcement laid scrim. In various embodiments, the method further comprises the step of adding a breathable or non-breathable adhesive to fill said gaps.

In various embodiments, a method of manufacturing a flexible-composite material comprises: producing thin unitape layers comprising fiber bundles consisting of a plurality of monofilaments by combining said monofilaments with a polymer resin and pultruding said monofilaments through a rotary die such that said monofilaments are spread by gaps and oriented parallel to each other; producing a scrim layer by combining at least two of said thin unitape layers; and bonding at least one of a woven fabric, non-woven fabric, and/or membrane layer onto at least one of said scrim layers. In various embodiments, the method further comprises the step of removing monofilaments to create and/or to augment said gaps. In various embodiments, the method further comprises adding a breathable or non-breathable adhesive to fill the gaps.

As described in more detail herein, various embodiments of the present disclosure generally comprise flexible-composite materials comprising at least one scrim reinforcement.

TABLE <NUM> provides a glossary of terms and definitions that may be used in various portions of the present disclosure.

In accordance with various embodiments, this disclosure provides a composite material that includes a scrim reinforcing element and at least two unidirectional tapes having monofilaments therein, all of such monofilaments lying in a predetermined direction within the tapes, wherein such monofilaments have diameters less than about <NUM> microns and wherein spacing between individual monofilaments within an adjoining strengthening group of monofilaments is within a gap distance in the range between abutting and/or stacked monofilaments up to about <NUM> times the monofilament major diameter.

In accordance with one aspect of the present invention, the thin unitape layers can be manufactured using fiber bundles consisting of a plurality of monofilaments that are combined with a polymer resin and pultruded through a rotary die such that the monofilaments are spread and oriented parallel to each other. In accordance with another aspect, the composite material includes a woven or non-woven reinforcement laid scrim, such as material produced by Saint-Gobain ADFORS.

In general, laid scrim is a lower cost reinforcing fabric made from continuous filament yarn in an open mesh construction. The laid scrim manufacturing process chemically bonds nonwoven yarns together, enhancing the scrim with unique characteristics. The laid scrim is a cost effective way to add fiber reinforcement to a composite material, especially in bias orientations (for example, about +/-<NUM>°, +/-<NUM>°, +/-<NUM>°) because the added processing steps to add unitape bias plies are skipped and replaced by inserting a pre-manufactured scrim. The laid scrim may be pre-coated with adhesive, pre-laminated to supporting films, or it may be necessary to sandwich it between unitape layers to glue it in place.

Additional films, laid scrims, membranes, fabrics, or coatings may be applied to the outer surfaces or layered within this composite material.

Scrim fiber types usable in the present system include, but are not limited to: Nylon, Polyester, UHPWPE (Spectra, Dyneema), para-Aramids (Kevlar, Nomex, Technora, Twaron), Liquid Crystal Polymer (Vectran), Polyimide, other synthetic polymers (PBO, PBI, PIBT, PBZT, PLA, PPTA), metal fiber, glass fiber, or any combinations thereof.

Scrim features and benefits include: dimensional stability, tensile strength, tear resistance.

In various embodiments, scrim construction patterns that find use in various embodiments of the flexible-composites of the present disclosure, include, but are not limited to, "side-by-side," "over/under," "tri-directional," "quad-directional," and "complexes," each of which are described in more detail in TABLE <NUM> below.

The composite material in accordance with the present invention contains one or more unidirectional fiber-reinforced layers each having thinly spread parallel fibers coated with adhesive (these layers are termed unitapes). In accordance with one aspect, the thin unitape layers can be manufactured using fiber bundles consisting of a plurality of monofilaments that are combined with a polymer resin and pultruded through a rotary die such that the monofilaments are spread and oriented parallel to each other. In various embodiments, the fibers that make up the unitape are spread and, either the distance between fibers is "gapped" such that an adhesive and fiber free space between each group of monofilaments is formed, or fiber tows are removed after the monofilaments have been spread resulting in a similarly gapped unitape. A scrim can be formed by bonding two or more of these unitape layers together. In an alternative embodiment, the filaments that make up each fiber are overspread to form a "gappy" unitape. In this embodiment the distance between filaments is "gapped" such that an adhesive and fiber free space is formed.

In various embodiments, a breathable or non-breathable adhesive may be used to fill the gaps.

In various embodiments, the present disclosure encompasses a method of manufacturing a flexible-composite material, said method comprising: providing at least one scrim layer; and bonding at least one woven fabric, non-woven fabric, and/or membrane layer onto said at least one scrim layer. The scrim layer comprises at least two unidirectional tape layers further comprising a plurality of parallel fiber bundles comprising monofilaments in an adhesive resin, wherein the fiber bundles are separated by gaps. In various embodiments, the scrim layer comprises a commercially available woven or non-woven reinforcement laid scrim. In various embodiments, the method further comprises the step of removing monofilaments from at least one of the unidirectional tape layers to create and/or to augment said gaps. In various embodiments, the method further comprises the step of adding a breathable or non-breathable adhesive to fill said gaps.

In various embodiments, a method of manufacturing a flexible-composite material comprises: producing thin unitape layers comprising fiber bundles consisting of a plurality of monofilaments by combining said monofilaments with a polymer resin and pultruding said monofilaments through a rotary die such that said monofilaments are spread by gaps and oriented parallel to each other; producing a scrim layer by combining at least two of said thin unitape layers; and bonding at least one of a woven fabric, non-woven fabric, and/or membrane layer onto at least one of said scrim layers. In various embodiments, the method further comprises the step of removing monofilaments from at least one of the unitapes to create and/or to augment said gaps. In various embodiments, the method further comprises adding a breathable or non-breathable adhesive to fill the gaps.

As illustrated in <FIG>, a flexible composite <NUM> comprises (a) a scrim or gappy layer comprising two or more unitape layers; and (b) one or more films, tapes, membranes, fabrics, or coatings disposed on either or both sides of the scrim. In the embodiment of <FIG> for example, unitapes are oriented in two directions (<NUM>°/<NUM>°) and combined with a scrim or other gappy layer and optional outer surface coatings to form a composite material.

<FIG> diagrammatically illustrates an embodiment of a flexible composite <NUM> in accordance to the present disclosure where gappy unitapes <NUM> and <NUM> are oriented in two directions (approximately <NUM>°/<NUM>°) and combined with both a scrim <NUM> and outer surface coatings <NUM> and <NUM> to form a composite material <NUM>.

The above mentioned "Gappy" Flexible Composite product is useful because it can be used in breathable membrane applications due to the adhesive/fiber free gaps. This material may weigh less than a version with a continuous layer of filaments. Additionally this composite material may have improved drape and moldability compared to a version with a continuous layer of filaments.

In various embodiments, additional films, scrims, gappy layers, membranes, fabrics, random oriented non-wovens, oriented non-wovens, or coatings may be applied to the outer surfaces or layered within this composite material.

In accordance with various embodiments, this disclosure provides a product wherein such at least one unidirectional tape is attached to such product.

In various embodiments, the flexible-composite materials of the present disclosure can be finetuned, at desired places on a product, to impart desired directional control of rigidity, flexibility and elasticity.

In various embodiments of the present disclosure, such a system comprises essentially one or more continuous "roll-to-roll" production process. In various embodiments, such a system is efficient, inexpensive, and useful.

In various embodiments of the present disclosure, the material layers are combined and cured together using pressure and temperature either by passing the stacked layers through a heated set of nips rolls, a heated press, a heated vacuum press, a heated belt press or by placing the stack of layers into a vacuum lamination tool and exposing the stack to heat. Moreover, external pressure, such as provided by an autoclave, may also be used to increase the pressure exerted on the layers. The vacuum lamination tool may be covered with a vacuum bag sealed to the lamination tool with a vacuum applied to provide pressure. Other lamination methods may also be suitable as would be known to one skilled in the art.

It should be noted that some low-surface-energy fibers require surface-energy modification prior to coating to promote bonding of the coating. Exemplary surface treatments include flame treatment, corona, plasma, and/or chemical treatment process. Subsequent, coating processes include, but are not limited to, curtain coating, gap coating, gravure coating, immersion coating, knife-over-roll coated, metered rod coating, reverse roll coating, roller coating, and extrusion coating.

Methods to partially or completely cure the above-noted coating include, but are not limited to: heated rolls, ovens, vacuum ovens, using light, Infrared, and/or UV curing. In one embodiment of the present system, a low temperature curing adhesive is used because the selected fabric is especially temperature sensitive. UWMWPE fabrics, for example, decompose at temperatures greater than <NUM>° F and the advised short-term duration temperature limit is <NUM>° C. In another embodiment, a thermoset or partially thermoset adhesive is used because this coating is more robust and does not degrade with heat and UV exposure. In another embodiment, a thermoplastic adhesive is used, such as urethane, when subsequent bonding and seaming processes require a thermoplastic coating. If adhesive is only partially cured during coating process, a subsequent curing step is used to fully cure the product, subsequent curing methods include heated rolls, ovens, vacuum ovens, using light, Infrared, or UV curing, and/or autoclaves.

In another embodiment of the present system, the uncured or partially cured coated fabrics described in the previous embodiments proceed to an autoclave curing process. The uncured or partially cured coated fabric is placed between layers of release liner (e.g. comprising a fluoro-polymer film, e.g. Teflon), next applied are layers of peel ply and breather, and the stack sealed in a vacuum bag onto a hard caul. The autoclave uses controlled temperature, pressure, and vacuum to remove entrapped air and volatiles from the coating and flow the coating across the surface and through the thickness of the fabric.

In various embodiments, unitape sheets are layered in multiple orientations to form a two directional fiber reinforced sheet (such as approximately <NUM>°/<NUM>°, +<NUM>°/-<NUM>°, +<NUM>°/-<NUM>°), or a four directional fiber reinforced sheet (such as approximately <NUM>°/<NUM>°/<NUM>°/-<NUM>°, <NUM>°/<NUM>°/<NUM>°/- <NUM>°), or other "custom" oriented fiber reinforced sheet with an endless number of orientations and layer combinations.

Prior to the curing process at least one plastic film, such as PET, PEN, Nylon, fluoro-polymer, urethane, or others, is laminated to one or both sides of the above-mentioned embodiments, or alternately between layers of the above-mentioned embodiments.

In other embodiments, a non-impregnated or impregnated fabric is laminated to one or both sides of the previous embodiments, or between layers of the above-mentioned embodiments, prior to the curing process.

In various embodiments, the composite material may include coloration of the matrix or membranes through use of pigments or dye sublimation.

In various embodiments, a fire retardant adhesive or polymer may be used, or fire retardants can be added to an otherwise flammable matrix or membrane to improve the flame resistance. Flame retardance or self-extinguishing matrix resins, or laminating or bonding adhesives such as Lubrizol <NUM>, can be used either by themselves, or in combination with fire retardant additives. Examples of retardant additives include: DOW D. <NUM> Brominated Resin, DOW Coming <NUM> Fire Retardant Resin, and polyurethane resin with Antimony Trioxide (such as EMC-<NUM>/10A from PDM Neptec ltd. ), although other fire retardant additives may also be suitable. Fire retardant additives that may he used to improve flame resistance include Fyrol FR-<NUM>, Fyrol HF-<NUM>, Fyrol PNX, Fyrol <NUM>, and SaFRon <NUM>, although other additives may also be suitable. Fire retardancy and self-extinguishing features can also be added to the fibers either by using fire retardant fibers such as Nomex or Kevlar, ceramic or metallic wire filaments, direct addition of fire retardant compounds to the fiber formulation during the fiber manufacturing process, or by coating the fibers with a sizing, polymer or adhesive incorporating fire retardant compounds listed above or others as appropriate. Any woven or scrim materials used in the laminate may be either be pretreated for fire retardancy by the supplier or coated and infused with fire retardant compounds during the manufacturing process.

Claim 1:
A flexible-composite material comprising:
at least one scrim formed from two or more layers of unitapes comprising a plurality of parallel fiber bundles comprising monofilaments in an adhesive resin wherein the fibers that make up the unitape are spread such that the unitapes have adhesive and fiber free spaces between each group of monofilaments,
at least one unidirectional tape layer, wherein the at least one scrim and the at least one unidirectional tape layer are bonded together; wherein said unidirectional tape layers comprise a plurality of parallel fiber bundles comprising monofilaments in an adhesive resin,
and two plastic films laminated to both sides of said flexible composite material.