CN117885418A

CN117885418A - Nonwoven flexible composite

Info

Publication number: CN117885418A
Application number: CN202410128270.4A
Authority: CN
Inventors: D·杜加尔; M·杰佛斯; T·W·斯威科克
Original assignee: Air Cruisers Co LLC
Current assignee: Air Cruisers Co LLC
Priority date: 2016-03-02
Filing date: 2017-03-02
Publication date: 2024-04-16
Also published as: WO2017151866A1; CN108698362A

Abstract

One or more embodiments of the present disclosure relate to nonwoven flexible composites. Embodiments of the present invention provide systems and methods for using nonwoven materials for evacuation slides, liferafts, life jackets, and other life-saving inflatable devices. The nonwoven material has a substrate layer with continuous filaments formed in various directions. The substrate layer then has a layer (e.g., a coating or film or both) on one or both surfaces of the nonwoven substrate.

Description

Nonwoven flexible composite

The present application is a divisional application of patent application with international application number PCT/US2017/020369, international application date 2017, 3/2/2018, 31 into the national stage of china, application number 201780014768.6, and the subject of the invention "nonwoven flexible composite".

Technical Field

Embodiments of the present disclosure generally relate to nonwoven flexible composites having particular utility in connection with evacuation slides, rafts, life jackets, or other emergency floatation devices. Such devices are typically formed from woven substrates, but the inventors have determined that the use of nonwoven substrates in combination with such devices may provide improved benefits.

Background

Federal aviation safety regulations require aircraft to provide evacuation and other safety measures for passengers. These include evacuation slides, life rafts, life jackets and other life-saving inflatable devices. For example, inflatable escape slides and liferafts are often constructed from assemblies of inflatable tubular structures forming air bundles sealed to each other. Inflatable escape slides and rafts also have non-air retaining features such as patches, floors, sliding surfaces, girts, handles and other features. A balance between strength and weight must be achieved during the design process. The material must be properly flame retardant, have the proper friction to allow the passengers to glide, have sufficient strength to withstand high expansion forces, resist tearing and abrasion, but must also be light enough so as not to excessively increase aircraft weight.

Evacuation slides, rafts, jackets or other life-saving inflatable devices, and their accompanying fittings and components are inflatable articles typically formed from a woven base substrate. The woven base substrate is typically covered or laminated to impart desired air retention characteristics thereto. By way of background, woven fabric constructions feature two sets of yarns: warp and weft yarns. The warp yarns are raised and lowered to create "shed" and the weft yarns pass through these shed perpendicularly to the warp yarns (and are referred to as fill or pick). The woven substrate imparts strength and rigidity to the inflatable tubular structure.

However, such a woven architecture introduces a "crimp effect" or undulation in the yarn because they alternate across and under each other during the weaving process. Yarn "crimp" is the undulation of warp and weft yarns that are interlaced together to create a fabric construction. Which is affected by the number of yarns, the fabric structure and the weaving tension associated with the strength of the woven fabric. If a load is applied to the woven fabric and the yarn is not crimped, then the full load will be subjected to tension at full strength. However, if the yarn is bent or curled, the initial load will be dissipated in the straightened bent yarn and subsequently uploaded. Thus, the use of a woven construction may result in a "low strength material". The crimping effect can also affect the fiber volume fraction, which ultimately leads to mechanical properties of the fabric compromise. A particular feature of the possible compromise is the tensile and compressive properties.

When woven fabrics are used in inflatable structures, and particularly when used to create inflatable tubular structures that are cylindrical in shape, the inflatable structures are subjected to loads in three directions. First, there is a circumferential or hoop stress, which is the normal stress in the tangential direction. Second, there is an axial stress, a normal stress parallel to the cylindrical symmetry axis. Third, there is radial stress, stress in a direction coplanar with the axis of symmetry but perpendicular to the axis of symmetry. The thin section of the inflatable fabric will typically have negligible radial stress. However, the hoop stress is typically twice the axial/longitudinal stress. The net effect is that inflatable tubes (such as evacuation slides or liferaft tubes) are subjected to twice as much stress in the circumferential direction as in the longitudinal direction. Fig. 3 illustrates an example of these two stresses and how they are experienced along a tubular structure. However, woven substrates currently used in inflatable tubular structures are constructed using yarns having the same or similar strength in both the hoop and axial/longitudinal directions. This may add unnecessary and undesirable weight to the overall structure.

Another challenge that may be presented by the use of woven substrates occurs during coating of the substrate. The interstices 10 between the yarns 12 may create high and low points that create challenges during the coating process. This is commonly referred to as the peak-to-valley effect and is illustrated by fig. 1. In order for these fabrics to "air-hold" or have "gas barrier" properties, the multilayer coating 14 is placed on top of each other until the desired thickness is achieved. The final top coat 16 may be applied to exhibit air retention characteristics. These multilayer coatings 14 are undesirable because they add weight and cost to such fabrics. Thus, improvements in fabrics for inflatable articles are desirable.

Nonwoven fabrics are materials made from fibers that are bonded together by chemical, mechanical, thermal, or solvent treatments. The term is generally used in the textile manufacturing industry to refer to materials that are neither woven nor knit like fabrics. The use of nonwoven materials is generally limited to the medical industry (for gowns and drapes), the filtration industry (for various types of filtration, including coffee and tea bags, vacuum bags, etc.), the geotextile industry (for foundation stabilizers, erosion control materials, sand and landfill liners), and other miscellaneous industries (such as for carpet liners, for diapers or feminine hygiene products, cleaning wet wipes, for boat sails, for parachutes, for backpacks or for batting in quilts or bedding). However, nonwoven materials have not been used in conjunction with inflatable life-saving equipment as described herein. The use of nonwoven materials for these applications presents unique challenges that the present inventors have addressed.

Disclosure of Invention

Embodiments of the invention described herein thus provide systems and methods for using nonwoven materials for evacuation slides, liferafts, life jackets, and other life-saving inflatable devices. The described nonwoven materials may also be used for non-air-retaining fittings or components of such devices, such as the sliding surfaces of evacuation slides, girts, handles, raft floors, patches, or any other feature. For example, in some other examples, non-air retaining features may be provided on evacuation slides, liferafts, life jackets, or other life-saving inflatable devices, including: a flexible composite comprising a substrate comprising a nonwoven material comprising a plurality of filaments; an adhesive or treating agent (primer) for bonding the filaments; and a coating or film or both on one or both surfaces of the nonwoven substrate; wherein the flexible composite is a high strength, lightweight material having a tensile strength of at least about 100 pounds per inch and a weight of about 8 ounces per square yard or more, wherein the flexible composite is adhered to the emergency device.

The nonwoven material has a substrate layer with filaments laid down in various directions. The substrate layer is then coated or applied on one or both sides as a coating or film. The coating may be in liquid form and applied to the material. The coating may be any of an adhesive, a treating agent, a resin, or other materials described herein. The film may be a layer applied to the material or a solid (non-liquid) sheet. In some cases, a film may be provided over the coating. The coating or film or both the coating and film together may be referred to herein as a "layer". The layer may be applied so as to provide the material with air-retaining characteristics so that it provides a gas barrier for the material. In other examples, the layer may be applied to impart some finish or feel to the material, such as a smooth sliding surface, a roughened liferaft base, or any other desired feature or finish, such as improved seam adhesion or abrasion resistance. The layer may provide protection against wear and also impart higher adhesion. In one example, the layer may be a polymer. In one example, the layer may be polyurethane. In other examples, the layer may be polyethylene, polypropylene, polyamide, polyethylene terephthalate (PET), polystyrene, ethylene vinyl acetate (EVOH), polyvinylidene chloride (PVDC), polycarbonate (PC), polyvinyl chloride (PVC), or any combination thereof. Other potential layers that form the layer are possible and are considered to be within the scope of this disclosure.

The binder or treating agent is particularly useful in cross-linking the materials/filaments to one another. This may result in high filament-to-adhesive adhesion, high filament-to-filament adhesion, high adhesive-to-coating adhesion, high adhesive-to-laminate film adhesion, high filament-to-coating adhesion, high filament-to-laminate film adhesion, or combinations thereof. Exemplary adhesives or treatments include, but are not limited to, solvent-based or water-based crosslinked polyurethanes. Other polymers that can be used as treating agents are listed above.

In one example, there is provided an inflatable evacuation slide, liferaft, life jacket or other life-saving inflatable device comprising: a flexible composite comprising a substrate of a nonwoven material comprising a plurality of filaments; an adhesive or treatment for bonding the filaments; and a gas barrier polymer layer on one or both surfaces of the nonwoven substrate; wherein the flexible composite is a high strength, lightweight material having a tensile strength of at least about 100 pounds per inch and a weight of about 8 ounces per square yard or less, wherein the flexible composite is adhered to itself to form a tubular structure or to another material.

In some examples, the substrate of nonwoven material includes multiple layers. The gas barrier polymer may be a coating or a film or both. The particular gas barrier polymer used may be polyurethane, polyethylene, polypropylene, polyamide, polyethylene terephthalate (PET), polystyrene, ethylene vinyl acetate (EVOH), polyvinylidene chloride (PVDC), polycarbonate (PC), polyvinyl chloride (PVC), or any combination thereof. The gas barrier polymer layer may have a thickness of between about 0.5 mils and about 2 mils.

In some examples, the substrate of nonwoven material includes a non-inflatable portion of the device. For example, it may form the floor material of a liferaft or evacuation slide, the girt material of an evacuation slide, or the handle or accessory patch of a liferaft or evacuation slide.

Filaments of the nonwoven material may be discontinuous or continuous in length. Filaments of the nonwoven material may be unidirectional or multidirectional. They may be in a randomly oriented filament arrangement or other random orientations. They may be one or more individual strands positioned according to the load that is structurally exhibited. They may be one or more additional strands positioned on top of the one or more individual strands. The substrate of the nonwoven material may be a customized fabric comprising filaments laid down in a specific direction of the intended stress to be experienced by the device to be manufactured. The device may be a tubular structure comprising a circumferential direction and a longitudinal direction, wherein there are more filaments in the circumferential direction than in the longitudinal direction. If the device has one or more bias seam locations, there may be more filaments at the bias seam locations than at other areas of the device. The apparatus may comprise tubular structures of different diameters, wherein the structure comprising a larger diameter comprises more nonwoven filaments than the structure comprising a smaller diameter.

The examples also relate to a method for manufacturing an inflatable evacuation slide, raft, life jacket or other life saving inflatable device, comprising: providing or obtaining a flexible composite material comprising a substrate of nonwoven material; applying a first layer on at least one surface of a substrate of nonwoven material; forming the material into a tubular structure; and applying a base plate or other fitting to the tubular structure.

Drawings

Fig. 1 shows a schematic side view of a woven prior art material.

Fig. 2A shows a schematic side view of a nonwoven material having filaments embedded in an adhesive matrix coated with layers on both sides.

Fig. 2B shows a schematic side view of a nonwoven material having filaments embedded in an adhesive matrix and laminated with layers on both sides.

Fig. 3 shows a side schematic view illustrating the various stresses experienced by the inflatable tubular element.

Fig. 4 shows a schematic side view of one potential filament placement along a tubular element.

Fig. 5 shows a schematic view of potential filament placement along an oblique seam.

Fig. 6 shows a schematic view of potential filament placement along a tapered tubular structure.

Fig. 7A shows filaments laid at an angle of 0 °. Fig. 7B shows filaments laid at a 90 ° angle. Fig. 7C shows filaments laid at 0 ° and 90 °. Fig. 7D shows a filament laid at a 45 ° angle. Fig. 7E shows filaments laid at a 30 ° angle. Fig. 7F shows filaments superimposed at 0 °, 90 °, 30 ° and 45 °.

Fig. 8 shows filaments laid in random orientations.

Fig. 9 shows a single strand of filaments positioned in different orientations according to load/force.

Fig. 10 shows a multi-strand filament positioned according to a desired high force direction.

Fig. 11 shows one example of a continuous filament laid on a substrate.

FIG. 12 shows one example of discontinuous filaments laid on a substrate.

Fig. 13 shows one example of discontinuous random filaments laid on a substrate.

Figure 14 shows one example of an evacuation slide that can be made using the nonwoven materials described herein.

Detailed Description

Embodiments of the present invention provide a substrate of flexible composite 20 with minimal to zero "curling effect". This may be generally referred to as "low curl" and the term is used to refer to materials that do not have fibers or filaments entangled or otherwise woven together. The materials may have particular use in connection with lifesaving inflatable devices, but their use is not limited thereto. Examples include evacuation slides, life rafts, life jackets, inflatable shelters, or combinations thereof. The described materials may be used to form the air retaining parts of these devices, but they may also be used to form other parts of the devices, such as the floor of a liferaft, the floor of an evacuation slide, the girt of an evacuation slide, the handle of an evacuation slide, etc.

The straight, non (or low) crimped filaments and/or yarns exhibit full load of tension at full strength. A flat nonwoven fabric 20 made from straight filaments 22 laid in certain orientations may exhibit a flat surface without the above-described peak-to-valley effect experienced by woven fabrics. It has been found that the planar surface may also be non-porous at least to some extent. This may result in the requirement for thinner layers. ( This is generally because in the case of woven fabrics, the coating 14 needs to fill the pores created by the peaks and valleys, as shown in fig. 1. In the case of a flat nonwoven fabric 20 as illustrated in fig. 2, these peaks and valleys are absent. )

Fig. 2A shows a straight laid filament 22 in an adhesive 24. The arrangement also has a first layer 26 and a second layer 28 on either side of the nonwoven substrate. Fig. 2B shows a straight laid filament 22 in an adhesive 24. The arrangement also has a layer 26 of coating or film or both and a layer 28 of coating or film or both on either side of the nonwoven substrate. Further details regarding specific materials that may be used are provided herein.

In addition, the nonwoven substrate may be stronger than conventionally used woven substrates. This can similarly result in a thinner layer required to air-hold such substrates. The inventors have found that the examples described herein may use approximately 50% less material, which may result in a finished material that is therefore approximately 50% lighter. Thus, the use of a nonwoven flat substrate can significantly reduce the weight of the layer compared to a woven substrate. Indeed, in some examples, minimum to no layers may be required.

While the embodiments described herein focus on lifesaving inflatable articles such as evacuation slides, evacuation slides/rafts, liferafts, emergency buoys, emergency floatation systems, and life buoys, it should be understood that the present disclosure is equally applicable to other textile-like devices including, but not limited to, inflatable/non-inflatable decontaminated shelters, inflatable/non-inflatable military shelters, marine baits, inflatable military targets, and space inflatable applications.

The nonwoven materials used in the present disclosure may include any number of materials. Examples include staple fibers or filaments, which may include cotton or other natural materials. Other examples include filament fibers, which include synthetic materials. One type of nonwoven material that may be used in connection with the present disclosure is a nonwoven material that is a laminate mixture of carbon and polymer filaments. In one example, the material is a reinforced laminate formed from one or more unidirectional tapes (also referred to as single tapes) laminated to a polymer film. The filament or monofilament material may be carbon or extended chain polyethylene or a liquid crystalline polymer embedded in a polymer matrix. The material may be an inorganic silicon. The material may be a monofilament aramid. The material may be nylon. The material may be polyester. The material may be cotton. The material may be Ultra High Molecular Weight Polyethylene (UHMWPE) filaments. The material may incorporate boron and/or ceramic. The material may be that commonly used for canvasses and/or kites. The material may be a combination of any of the above options. Additional examples are described by U.S. patent No.5,333,568, the entire contents of which may be considered useful herein. Other materials are possible and are considered to be within the scope of the present application. The type of filament used may be optimized depending on the particular device to be manufactured. In some examples, the filaments used may have a diameter up to about 5 times smaller than conventional strands or threads used in woven materials. In addition, the nonwoven fabric may be about 1/3 the thickness of a conventional woven fabric for inflatable articles due to the possibly increased strength due to the configuration of the present disclosure.

Since the final materials described herein are designed for use in conjunction with inflatable structures that must withstand high inflation pressures, the materials used must be designed to withstand such pressures. By way of background, current slides, lifeboats and life jacket fabrics must meet FAA requirements listed under the appropriate technical standards guidelines (TSOs). The TSO specifies the Minimum Performance Standard (MPS) that these emergency evacuation products must meet. Current woven inflatable air maintenance fabrics have an average finished fabric weight of about 8.0 ounces per square yard (oz/sq yard). (typically broken down to 50% (4.0 oz/square yard) is the base weight and 50% (4.0 oz/square yard) is the coating and/or laminate film weight.) these inflatable fabrics must also meet minimum tensile strengths of 190 lbs/inch (for slides and liferafts) and 210 lbs/inch (for life jackets). These are the current requirements set by regulatory authorities such as FAA. However, it is believed that the existing concepts may also find use on materials having a tensile strength of 100 lbs/inch, 120 lbs/inch, 130 lbs/inch, 140 lbs/inch, 150 lbs/inch, 160 lbs/inch, 170 lbs/inch, 180 lbs/inch, or any integer therebetween.

Typically, multiple pieces of fabric (panels) are joined together to form a tubular structure. Thus, the strength requirements are not limited to the body fabric (part of the inflatable tube) but are also required for the seam area. In order for the gas to remain inside the tube for a long duration, the seams must be sealed together (via heat welding or adhesive bonding) to prevent leakage. Such seams must meet minimum shear strengths of 170 lbs/inch (at room temperature) and 40 lbs/inch (at high temperatures of 140°f). Such seams must have peel strengths of 5 lbs/inch (slide and liferaft) and 10 lbs/inch (life jacket). The requirements outlined herein are current requirements; it should be understood that the materials described in this disclosure may have various features that are modified to meet other requirements set in the future or by different regulatory authorities. Safe inflatable products also need to meet high pressure testing (also known as overpressure testing) requirements where the equipment must withstand high inflation pressures without any damage to seam integrity. For example, the slides are required to withstand twice the maximum operating pressure for at least one minute without failing. Depending on the pipe diameter and the maximum operating pressure established for the slide, the hoop stress/load/force (which is the greater of the two stresses experienced by the joint) may vary. For example, a 24 "diameter tube having a maximum operating pressure of 3.5psi will experience a hoop stress of about 84 lbs/inch.

As discussed above, existing nonwoven fabrics available on the market and described in the prior art documents are mainly used for low cost items of merchandise such as filters, patient clothing, sanitary products, etc. These fabrics are low cost materials where the necessary and achieved strength is not close to that required for inflatable products for safety applications subjected to large pressure loads. Existing inflatable nonwoven materials do not meet any of the TSO strength requirements listed above at the desired weights. This means that in order to achieve the desired strength, the materials will need to be so heavy that they will be difficult to store on vehicles where weight reduction is a major concern. In contrast, at the desired low weight, the currently available nonwoven materials will not have the required strength. Accordingly, the present inventors have specifically described nonwoven materials having a strength that allows them to be used in the safety inflatable applications described herein, while also having a desirably low weight.

Thus, the nonwoven substrates used are highly engineered nonwoven substrates made with specifically engineered filaments and polymer layers to achieve the highest strength to weight ratio on the inflatable air maintenance fabric used in the lifesaving inflatable device. In some specific examples, the material achieves the following fabric tensile strengths: up to or greater than about 190 lbs/inch for slides and rafts; and up to or greater than about 210 lbs/inch for life jackets. In other examples, the material achieves a fabric tensile strength of up to about 100 lbs/inch. In other examples, the material achieves a fabric tensile strength of up to about 120 lbs/in. In other examples, the material achieves a fabric tensile strength of up to about 130 lbs/inch. In other examples, the material achieves a fabric tensile strength of up to about 140 lbs/inch. In other examples, the material achieves a fabric tensile strength of up to about 150 lbs/in. In other examples, the material achieves a fabric tensile strength of up to about 160 lbs/inch. In other examples, the material achieves a fabric tensile strength of up to about 170 lbs/in. In other examples, the material achieves a fabric tensile strength of up to about 180 lbs/inch. In some specific examples, the material achieves a shear strength of up to or greater than about 175 lbs/inch (at room temperature) and 40 lbs/inch (at 140°f). In some specific examples, the material achieves seam peel strength up to or greater than about 5 lbs/inch (slides and liferafts) and 10 lbs/inch (life jackets). In some specific examples, the material may withstand a TSO overpressure requirement of 2 times the maximum operating pressure.

Even when nonwoven materials are used for air mattresses, the materials are not manufactured or designed to withstand the types of inflation pressures described herein. These materials are focused on low cost. Thus, nonwoven air mat materials are typically made from random staple fibers that do not have high strength. The use of inflation pressures on camping air mattresses as required by aircraft regulations will result in low cost air mattresses splitting. For clarity, these air cushions have a tensile strength of about 100 pounds per inch or less, a weight of about 16 ounces per square yard or more, and a burst (burst) strength of less than about 5 psi. Nor have they been designed to operate under extreme temperature conditions, such as-40°f up to 160°f.

Exemplary test data provide that using the techniques described herein can provide an inflatable structure having a strength to weight ratio of about 190/4=47.5 compared to the current state of the art woven coated fabrics having low strength and high weight. In contrast, woven composites typically have a strength to weight ratio (minimum) of about 190/8=23.75. Examples of other nonwoven strengths versus weight include, but are not limited to, any arrangement of 190/7, 190/6, 190/5, 190/4, 190/3, and 190/2, or fractions thereof. (these examples provide a tensile strength of 190 pounds per inch and a weight of about 2 ounces to about 7 ounces per square yard).

In addition to laying down filaments on an adhesive substrate or paper, other techniques can be used to make a flexible nonwoven composite as a web. The described nonwoven materials may be manufactured in any number of ways. They may be manufactured using mechanical means, heating means, water means, or a combination thereof. Some specific examples of ways in which the nonwoven used in the present disclosure and appended claims may be made include, but are not limited to, felting, adhesive bonding, textile laying (spin lay), carding, spinning (spin bonding), wet laid filaments, stitching or stitch bonding, needle punching or needle punching, calendaring, hydroentangling with high jet pressure, and/or hot air bonding or thermal bonding. Filaments of the fibers may be manufactured by spinning, wet bonding, dry bonding, or any other suitable method.

As illustrated in fig. 2A, the monofilaments 22 may be uniformly embedded in the adhesive matrix using an elastomeric polymer matrix or bonding adhesive 24. In other examples, the filaments may be pre-coated to become "tacky filaments" that can be laid down on a paper substrate. The paper may be peeled apart and the resulting filaments may be sandwiched by layers of polymer film. In contrast to woven filaments, depositing filaments in this manner can help solve the above-described problems created by woven products. Alternatively, the solution provides a flat substrate. The substrate may form a reinforcing material positioned between an upper layer and a lower layer of the polymer layer. As described in more detail below, filaments may be laid down in various configurations to provide engineered filament placement for a desired use. The filaments may be continuous or discontinuous or any combination thereof. The filaments may all have the same diameter, or filaments of various diameters may be used. The layers of monofilaments may be single layers or multiple layers.

When nonwoven materials are used for canvases and kites, the polymer film used in the above arrangement is typically Mylar. The filaments are laid into the resin and the top and bottom layers of the maillard are positioned on either side of the filaments. The material is autoclaved so that heat and pressure can fuse and cure the individual components together.

However, the present inventors have found that the use of mylar as a polymer film is not optimal for securing to or otherwise use with an adhesive used to manufacture a lifesaving inflatable device. Even when assisted with a cross-linked adhesive, the maillard as a low surface energy substrate does not adhere well to the filaments, coating and/or film, thus causing delamination and peeling of the filaments from the coating and/or film when under the prescribed load of the inflatable security product. Alternatively, the materials of the present disclosure use polyurethane layers 26, 28 on one or both sides of the nonwoven-based substrate/structure. Other examples of layers include, but are not limited to, polyvinylidene chloride (PVDC), polyvinyl alcohol (PVOH), ethylene vinyl acetate (EVOH), polyethylene terephthalate (PET), polyethylene (PE), polyamide, polypropylene (PP), polylactic acid (PLA), or any other suitable polymer, or combinations thereof. Fig. 2A and 2B provide schematic diagrams illustrating a configuration having layers on both sides of a substrate. It will be appreciated that the layer may also be applied to only one side or surface of the substrate. It has unexpectedly been found that by replacing the mylar film with a polyurethane (or other) layer, the nonwoven material is optimally used in the lifesaving inflatable devices described herein.

Polyurethane is formed by the reaction of two components: an isocyanate component and a polyol component. Polyurethanes are generally high molecular weight polymers having a wide range of properties due to wide formulation variations. Exemplary variations and types of polyurethanes that may be used in connection with the present disclosure include, but are not limited to:

aromatic or aliphatic polyurethanes;

thermoplastic Polyurethanes (TPU) (thermoplastic polyurethanes are polymers that can be melted and recombined; they are elastic and highly flexible), thermoset-based polyurethanes (thermoset polyurethanes are polymers that cannot be melted and recombined, and are generally more durable than thermoplastic polyurethanes);

polyester TPU, which has high resistance to oils and chemicals and provides excellent abrasion resistance;

polyether TPU's, which have a specific gravity slightly lower than polyester and polycaprolactone grades and provide low temperature flexibility, good abrasion resistance and tear resilience, are resistant to microbial attack, and provide good hydrolysis resistance, making them suitable for applications where water needs to be considered; and

polycaprolactone TPU, which has the toughness and resistance inherent in polyester-based TPU, combined with low temperature properties and relatively high hydrolysis resistance.

In addition, the adhesives/resins, coatings, and films to be used on the nonwoven flexible composites described herein need not be limited to polyurethane materials. Other exemplary polymer layers that may be used in place of or in combination with the polyurethane include, but are not limited to, polyvinylidene chloride (PVDC), polyvinyl alcohol (PVOH), ethylene vinyl acetate (EVOH), polyethylene terephthalate (PET), polyethylene (PE), polyamide, polypropylene (PP), polylactic acid (PLA), or any other suitable polymer or combination thereof.

In one example, the layer may have a thickness of about 0.5 mils to about 5 mils. In another example, the layer may have a thickness of about 0.5 mils to about 2 mils. In another example, the polyurethane layer may have a thickness of about 1 mil.

During manufacture, an adhesive may be applied to the filaments in addition to being mounted on the film. This may further assist in adhering the material to itself or to other material portions for use in manufacturing the desired shape.

In addition, the adhesive used by the present assignee is considered to bond with the polyurethane layer so that the material becomes a unitary, one-piece, or otherwise monolithic construction of material that is crosslinked and will not delaminate from itself. One exemplary adhesive that has been found to be successful is an isocyanate-based adhesive. Other adhesives that may be used include, but are not limited to, those listed above.

This may further aid in the described bonding/crosslinking if the filaments are additionally coated with an adhesive (in addition to or instead of polyurethane or other adhesive). For example, the use of isocyanate-based adhesives with polyurethane films coated or laminated to a filament substrate may provide reinforcement materials specifically designed for high stress applications. An isocyanate-based binder may be added during formation of the substrate; isocyanate-based adhesives may be used as adhesives on the outside of the material; and/or isocyanate-based adhesive treatments may be used. If the materials are welded and no specific adhesive is used, an isocyanate-based adhesive may be incorporated during formation of the base adhesive and/or an isocyanate-based adhesive treatment may be applied over the joint to be welded.

Filament orientation can play an important role in determining the stretch, tear and puncture properties of a fabric. In one example, regions of material loaded with more filaments than other regions of material may be provided. Embodiments of the present disclosure provide various filament orientations that may include different filament thicknesses and/or filament densities at mitered joints or seams, at diameter variations (coning of the fabric), and/or at hoop stress versus length locations.

For example, referring now to the orientation of the flexible composite panel/substrate formed for the evacuation slide, a relatively high load is generated by the air pressure used to expand the tube forming the air beam. Alternatively, the life raft floors, evacuation sliding surfaces, handles and other fittings on the equipment or non-air retaining features are also subjected to high pressures. These high loads also need to be maintained in order to maintain structural rigidity under the weight of the slide and under the weight of the passengers during use. The load across the diameter of the tube (in the circumferential direction 32) is typically greater than the load in the length or longitudinal direction 34 of the tube. This is illustrated by way of example in fig. 3. Since the tubes forming the air bundles on the evacuation slides are not subjected to a balanced load, the fabric to be manufactured can be designed to be stronger in the direction opposite to the other direction. Accordingly, various engineered filament orientations are also described herein. The engineered filament orientation may provide enhanced strength at certain areas where the inflatable life-saving structure is typically subjected to high stress. For example, more filaments or reinforced filament areas may be provided on a tube where higher stresses are to be experienced. These filaments may be in the same or different directions.

For example, as illustrated in fig. 4, filaments 22 may be provided in circumferential direction 32 that correspond to twice as many as in axial/longitudinal direction 34. In other examples, 1.5 times the filaments, three times the filaments, four times the filaments, or any other desired intensity parameter may be provided.

In the example shown in fig. 5, more filaments may be bundled or stacked at miter or joint location 36. In the example shown in fig. 6, a larger diameter tube loaded with more filaments may be designed. In this example, there is a tapered section 38 of the evacuation slide loaded with more filaments at the larger diameter portion 40. These options allow for varying and tailoring the filament orientations so that they are strongest at the desired location while still maintaining the lightest possible material at other locations.

In addition, when nonwoven materials are used in canvasses and kites, the filaments used are unidirectional filaments. Even if multiple substrate layers are used in order to provide filaments of different directions, each substrate itself has filaments in the same direction. In contrast, the inventors have determined that placing filaments in multiple directions on a single sheet can increase the strength of the resulting product.

For example, each plate may be customized to have a particular filament orientation as desired. They may be unidirectional or multidirectional or any combination thereof. For woven cloths, the filaments are always at a 90 ° angle with respect to each other. Fig. 7A illustrates a filament at an angle of 0 °. Fig. 7B illustrates a filament at a 90 ° angle. Fig. 7C illustrates filaments superimposed or interwoven at 0 ° and 90 ° angles. This is the only possible result of a woven material. However, other combinations are possible with nonwoven materials. The filaments may be oriented at 0 °, 25 °, 30 °, 45 °, 60 °, 90 °, or any desired angle. The filaments may be laid in any orientation desired. Only a few examples are illustrated by fig. 7D-7F. Fig. 7D illustrates a filament at a 45 ° angle. Fig. 7E illustrates a filament at a 30 ° angle. Fig. 7F illustrates a combination of filament substrates superimposed on one another, providing a material with a combination of angled filaments. In this example, 0 °, 90 °, 30 °, and 45 ° angles are illustrated, but it should be understood that other combinations are possible and are considered to be within the scope of the present disclosure.

In addition to providing multiple filaments that can be stacked relative to one another to provide customized or engineered filament positioning/orientation, single continuous filaments can be laid down at multiple angles. Fig. 8 illustrates an example. In this example, there are three different angles of filaments 22a, 22b, 22c provided on a single substrate. This example may be referred to as randomly oriented filaments.

In another example, a single strand of filaments/yarns may be provided that are positioned according to the expected load/force to be exhibited on the inflatable product. In fig. 9, a single filament 22 is illustrated that is wound in a first direction 42, bent into a second direction 44, and then bent into a third direction 46. This is just one example. Other directions may be provided. Additional filament/yarn(s) 22 may also be positioned on top of the first filament/yarn 22. An example of this is shown by figure 10. In this example, the filaments are reinforced in the direction of the highest expected force.

The filaments used may be continuous fibers as shown in fig. 11. The filaments used may be discontinuous filaments as shown in fig. 12. The filaments used may be discontinuous random filaments as shown in fig. 13.

Additionally or alternatively, multiple reinforced sheets of monofilament material may be used between the polymer layers. In one embodiment, about two to about ten reinforced sheets oriented in different directions may be used as the reinforcing material between the polymer layers. For example, two or more filament sections or substrates may be positioned at 90 ° to each other to help provide a reinforced material. For example, individual filament segments or substrates may have filaments extending at different angles relative to one another to help provide a reinforced material. Other options are possible and are considered to be within the scope of the present disclosure.

Fig. 14 illustrates one example of an evacuation slide 50 that may be made using the nonwoven materials of the present disclosure. Slide 50 includes sliding surface 52, air retention tube 54, girt 56, handle 55, and accessory patch 60. The nonwoven materials described herein are directed to the manufacture of air containment tube 54. It should also be appreciated that the sliding surface 52 or any other surface may be made of a similar nonwoven material. The sliding surface 52 may be bonded to the air retaining tube 54 using the same or similar techniques as the manner in which the ends of the air retaining tube 54 material are bonded to one another. For example, isocyanate-based adhesives may be used. In other examples, alternative adhesives described herein may be used. In other examples, various forms of welding techniques may be used.

Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope and spirit of the disclosure or the following claims.

Claims

1. An inflatable evacuation slide, slide/raft, liferaft, life jacket or other life-saving inflatable device comprising:

a flexible composite material comprising:

a substrate of nonwoven material comprising a plurality of filaments;

an adhesive or treatment for bonding the filaments; and

a layer of a gas barrier polymer on one or both surfaces of the substrate of nonwoven material;

wherein the flexible composite is a high strength, lightweight material having a tensile strength of at least about 100 pounds per inch and a weight of about 8 ounces per square yard or less;

wherein the flexible composite material is adhered to itself to form a tubular structure or to another material.