Fire barrier cloth

Abstract

The barrier comprises flexible fire retardant (FR) materials coupled together with non-flammable flexible material. Preferably one FR material 12 is interliner cloth comprising wool, FR viscose and / o

Description

Field of the Invention This invention relates generally to an integrated flexible fire barrier cloth and, more particularly but not necessarily exclusively, to an integrated fire barrier cloth suitable for use in upholstering seats and the like in at least some categories of public service vehicles. Background of the Invention Vinyl-coated polyester is a flexible fabric commonly used for upholstery and furniture coverings, amongst other applications. It is typically made up of a polyester scrim (woven material). A bonding or adhesive agent, and an exterior polyvinyl chloride (PVC) coating. The scrim supports the coating (which is initially applied in liquid form) and provides the tensile strength, elongation, tear strength, and dimensional stability of the resulting fabric. In order to achieve certain desired fire retardancy properties, the PVC coating liquid (vinyl Organisol or Plastisol) must have fire retardants (i.e. chemicals) added to it, and further chemicals may also be added to achieve any desired colour and water / mildew resistant properties. In order to meet the stringent Crib 5 and Crib 7 fire rating regulations (or international equivalents safety standards) for fire retardancy applied in many environments and applications, high levels of fire retardant chemicals are typically added to the PVC coating liquid. This aspect, coupled with the need to employ a bonding agent or adhesive results in a significant environmental footprint in relation to such textiles, both during manufacturing and at the time when the fabric is required to be disposed of at the end of its useful life. Many seating applications require a degree of ‘buoyancy’ to ensure that the seating is comfortable and incorporates a degree of padding to counteract the user’s weight and ensure that they are not just being supported by the hard metal seat frame beneath the seat covering. To this end, it is known to incorporate a buoyant material, such as foam or interliner material, underneath the outer cover, in order to provide this padding. Barrier felt, for example, is known that can meet at least the crib 5 fire rating, usually when used in conjunction with a fire retardant combustion modulated high resilience (CMHR) flexible foam although, as the upholstery wears over time (an inevitably stretches a little), air gaps can be created between the interliner material and the foam, which can reduce its fire resistance and fire retardance properties. Furthermore, whilst the tensile and tear strengths of conventional vinyl-coated polyester are considered to be relatively high, once there is a small cut or other imperfection in the fabric, it is relatively easy to tear along the weave of the underlying scrim. This creates a hole that reaches into the foam and / or interliner beneath and, whilst the vinyl-coated outer textile (usually provided by the upholsterer) may meet the crib 5 or crib 7 fire levels, once it has been damaged in this way, its fire level is may be reduced to the fire level of the foam / interliner beneath, which may be lower. As a result, the seat as a whole would fail the required fire levels for public service vehicles (for example) unless and until the outer textile has been replaced and repaired. Also, in the event of damage to the outer textile, a flame could penetrate the material below and create a vertical flame at the rear of the seat. Still further, there exists another regulation with which some such upholstered seats are required to comply. UN Regulation No. 118 defines uniform technical prescriptions concerning the burning behaviour and / or the capability to repel fuel or lubricant materials used in the construction of certain motor vehicles. In order to comply with UN Regulation No. 118 (R118), it is necessary to ensure that the materials used in the construction of such motor vehicles meet specific fire safety standards. The R118 requirements are exceptionally high and difficult to meet, and, whilst the R118 regulation has been in force for some years, some of its individual criteria have been phased in over a transition period, which has meant that, until now, many manufacturers of public service vehicle seating (and the like) and public service vehicle operators have not yet had to comply with all of the criteria. However, that is set to change in the coming months, when the transition period looks set to expire and all R118 criteria will have to be met. One of the most challenging of those criteria to meet is that set out in Annex 8 of the R118 regulation, namely the ‘vertical test’. This test determines the vertical burning rate of the material, and the regulation specifies that the vertical burning rate must be no more than 100mm / min. Even if the material meeting the R118-Annex 8 requirements on its own can be obtained, once it is combined, in a seat cover, with other layers of material for aesthetic, protection and comfort purposes, the resultant seat cover, as a whole, cannot pass the R118-Annex 8 vertical test and, whilst it is highly desirable to provide a single barrier cloth fo upholstering, for example, a public service vehicle seat, it has, thus far, eluded the industry as to how this can be achieved in an environmentally-friendly and commercially-viable manner, to provide a comfortable, padded cloth that is sufficiently pliable to be workable in normal upholstery methods, and that also passes the R118-Annex 8 vertical test. It is an object of aspect of the invention to address at least one or more of these issue, and to provide an integrated fire barrier cloth that, not only passes the crib 5 or 7 fire retardancy standards, but is also able to pass the UN Regulation 118 - Annex 8 vertical test; and a method of manufacturing such an integrated fire barrier cloth. Statements of Invention In accordance with a first aspect of the invention, there is provided an integrated fire barrier cloth comprising a first layer of flexible material that meets at least fire level Crib 7 and a second layer of flexible material that meets at least fire level BS5852 0 + 1, the first and second layers of material being permanently coupled together with a non flammable flexible material therebetween. Beneficially, the non flammable material may meet fire level FMVSS302. In an embodiment, the first layer of material may comprise an interliner cloth, which may comprise one of natural wool and FR viscose, 100% wool, 100% FR viscose, polyester or polyester mix. In an embodiment, the second layer of material may, beneficially, comprise a flexible thermosetting polymer layer, such as polyvinyl chloride. In an embodiment, the second layer of flexible material may comprise a substrate carrying a layer of flexible thermosetting polymeric material, which may, once again, comprise or include one or both of polyvinyl chloride (PVC) and polypropylene. The substrate may, for example, comprise a textile and comprise or include one or more of polyester, wool, viscose, melamine and halogen-containing fibres. As an example, the textile substrate may comprise 100% polyester spunbond. In alternative embodiments, the substrate or backing carrying the flexible thermosetting polymer layer may comprise a flexible thermoplastic polymer such as polypropylene. Whether the layer of flexible thermosetting polymer material is carried on a substrate or not, at least one flame retardant chemical may be incorporated therein. In a preferred embodiment, there may be provided an integrated fire barrier cloth comprising a flexible foam substrate bonded or otherwise coupled on one surface thereof to a said first flexible layer of material and bonded or otherwise coupled on the opposing surface thereof with a said second flexible layer of material. The flexible foam substrate may comprise high resilience foam, and beneficially combustion modulated high resilience (CMHR) foam. In an embodiment, the foam may comprise polyurethane, and the thickness thereof may be 2-10mm. Foam substrates, such as a polyurethane foam substrate that meets the above-referenced fire level FMVSS302 will be known to a person skilled in the art and will not be described in any further detail herein. Thus, in an example integrated flexible fire barrier cloth, by sandwiching a flexible (e.g. polyurethane) foam substrate meeting at least fire level FMVSS302 between an interliner cloth meeting at least fire level crib 7 and a flexible thermosetting polymer layer (with or without a textile backing) meeting fire level BS5852 1 + 0, the inventor has created a fire barrier cloth that is not only more than the sum of its individual parts, but also passes the (very different) fire safety test set out in Annex 8 of UN Regulation 118. Many attempts have been made by others to achieve this result, but there is currently nothing available on the market that meets these fire levels and has the flexibility and versatility required to allow it to be used in multiple applications. In an example integrated flexible fire barrier cloth, the three layers are bonded together. Many different types of bonding such materials together will be known to a person skilled in the art. Purely by way of example, flame lamination or even adhesive may be used. These and other aspects of the invention will be apparent from the following detailed description. Brief Description of the Drawings An embodiment of the invention will now be described, by way of example only, and with reference to the accompanying drawing, in which Figure 1 is a cross-sectional view of a section of an integrated fire barrier cloth according to an exemplary embodiment of the invention. Detailed Description In the following description of various exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which are shown, by way of examples and illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that variations and modifications may be made, without departing from the scope of the invention as defined in the appended claims. The following detailed description is therefore not to be taken in a limited sense. The specification may refer to “an”, “one” or “some” embodiment(s) in some parts. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature applies to only one embodiment. Single features of different embodiments may also be combined to make another embodiment. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and / or “comprising”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, operations, steps, elements, components and / or groups thereof As used herein, the term “and / or” includes any and all combinations and arrangements of one or more of the associated listed items. Directional descriptors such as upper, lower, left, right, clockwise, anti-clockwise, front, rear and other similar adjectives are used for clarity and refer to the orientation of the invention as illustrated in the drawings, however it will be clear to those skilled in the art that the invention may not always be oriented as illustrated and the invention is not intended to be limited in this regard. Thus, and referring to Figure 1 of the drawings, an aspect of the invention comprises an integrated fire barrier cloth (and a method of manufacture thereof) wherein first 10 and second 12 layers of material are permanently coupled together with a layer 14 of material sandwiched therebetween. Each layer of material (at least) meets a specified fire level, with the surprising technical effect that the cloth as a whole can pass another (different and more difficult) test, namely the vertical burning rate test set out in Annex 8 of UN Regulation No. 118. The cloth combines these fire safety characteristics with sufficient comfort and workability to make it suitable for upholstering, for example, public service vehicle seats. And, even if the outer covering of the seats is damaged or tom, the fire barrier cloth beneath can still provide the required fire safety characteristics. In an exemplary embodiment, first and second layers of material 12, 14 may be coupled together by, for example, a layer of non flammable synthetic fibres used in a high frequency or ultrasonic welding process to permanently couple the first and second layers of material 12, 14 together. However, in a preferred example integrated fire barrier cloth, a first layer of material 12 is permanently coupled to a first surface of a layer 16 of non flammable foam, and a second layer of material 14 is permanently coupled to the opposite surface of the layer 16 of non flammable foam. The first and second layers 12, 14 of material may be permanently coupled or bonded to the non flammable foam by any suitable means, such as, for example, adhesive or flame lamination. Other suitable textile bonding methods will be apparent to a person skilled in the art, and the present invention is not necessarily intended to be limited in this regard. The foam (or other material) ‘sandwiched’ between the first and second layers 12, 14 of material should meet (at least) the fire level FMVSS302, but otherwise is not necessarily limited, either in thickness or composition, as its primary role is to permanently bond the first and second layers 12, 14. For completeness, The Federal Motor Vehicle Safety Standard No. 302 (FMVSS 302), Flammability of Interior Materials, is used to determine the bum resistance capabilities of materials used in the occupant compartments of motor vehicles. This test is typically performed on materials in passenger cars, trucks, and buses. Foam substrates, such as a polyurethane foam substrate, that meet the above-referenced fire level FMVSS302 will be known to a person skilled in the art. Whilst not essential for all embodiments of the invention, using a foam as the middle layer 16 does have the benefit of providing additional padding within the textile, and tests have shown that fire retardant, combustion modulated high resistance (CMHR) flexible (e.g. polyurethane) foam can provide the workability and padding required for many seating applications, as well as exhibiting the required fire level. The foam could be of any required thickness, although a range of 2-10mm thickness is deemed to be suitable for most public service vehicle upholstering applications. The first layer 12 of material is designed to form the ‘outer’ layer of the integrated fire barrier cloth (i.e. the layer nearest the outer cover of a seat, and, of course, nearest its user). The first layer 12 of material meets the fire level crib 7. Crib 7 is the short name for the test known as BS5852 Ignition Source 7 - wood crib, which is a stringent flammability test used primarily on fabrics and materials for upholstered furniture in contract and commercial environments. It assess how resistant the material is to ignition and flame spread when exposed to a wooden crib fire source, and will be known to a person skilled in the art. The first layer 12 of material beneficially, comprises an interliner cloth. Interliner cloths meeting fire level crib 7 and intended for use, on their own, in upholstery applications are known, and the present invention is not necessarily intended to be limited to specific interliner cloth compositions. However, suitable interliner cloths comprise natural fibre wool and FR viscose, 100% wool, 100% FR viscose, and even some polyesters or polyester mixes. A benefit of these types of materials is that no additional (chemical) flame retardants need to be added or impregnated to meet the fire level crib 7. The second layer of material 14 is designed to form the innermost layer of the integrated fire barrier cloth (i.e. the layer nearest the metal frame of the seat). The second layer of material comprises a thermoplastic polymer layer that meets (at least) the fire level BS5852 0 + 1, which is a British Standard that describes the ignitability of components used in upholstered furniture. For completeness, BS 5852:2006 describes best practice methods to assess the ignitability of single material combinations, such as covers and fillings used in upholstered seating, or complete items of seating. These tests determine the effects of a smoldering cigarette, or other flaming ignition sources such as burning matches or a four-sheet full-size newspaper. This standard can be used to establish the potential ignitability of components in conjunction with other specified materials. Source 0: smoldering cigarette A cigarette is put along the crevice of the test rig and allowed to bum over its entire length. If no flaming or progressive smoldering is observed on both cover and interior material, the test is recorded as no ignition and the material passes the test.BS5852 -Part 1 - Simulated Match - Passed Source 1: simulated match A burner is lit, held along the crevice of the test rig for 20 seconds and then removed. If no flaming or progressive smoldering is observed on both cover and interior material, the test is recorded as no ignition and the material passes the test. Thermoplastic polymers such as polyvinyl chloride (PVC) that are able to meet these standards will be well known to a person skilled in the art. In the case that the first and second layers 12, 14 of material are coupled together with a layer 16 of material, such as the foam described above, ‘sandwiched’ between them, the thermoplastic layer may be directly applied (bonded or even coated) onto the surface of the foam layer 16. In other embodiments (with or without the foam layer), the second layer of material may comprise a thermoplastic layer on a backing material, such as a felt substrate. The thermoplastic layer may, beneficially comprise polyvinyl chloride (PVC), which may have incorporated therein at least one flame retardant chemical (e.g. antimony oxide or alumina trihydrate), but this is not always essential. Where utilized, the non-woven backing material or substrate of the second layer 14 of material may comprise a non-woven fabric such as a synthetic textile fabric (e.g. spunbond). Purely by way of example, the backing material carrying the thermoplastic layer of the second layer 14 of material may comprise spunbond polyester, wool or viscose (rayon). Melamine and / or halogen-containing fibres may alternatively be utilized. An example of a suitable textile for use as the second layer 14 of material in an example integrated fire barrier cloth is described in GB2542344, but it is to be understood that the present invention is not necessarily intended to be limited in this regard. Thus the integrated fire barrier cloth comprises a first layer of material meeting (at least) the fire level crib, permanently coupled to a second layer of material meeting (at least) fire level BS5852 0 + 1, with a non flammable substance therebetween, with the surprising technical effect that the resultant cloth, not only meets those fire levels, but also passes the (quite different, and more difficult to achieve) vertical fire test stipulated in Annex 8 of UN Regulation 118. Even if the outer covering of a seat upholstered with the fire barrier cloth is compromised, and a flame reaches and penetrates the interliner (i.e. the first layer of material), the thermoplastic backing layer acts to prevent, or at least significantly limit, the vertical ‘creep’ of the flame, thus preventing the seat from being engulfed at its rear (potentially behind a user sitting on a seat) by tall flames. It is to be understood that the fire level of the integrated fire barrier cloth is, surprisingly, not only more than the sum of its individual layers, but now also passes an entirely different fire safety test, namely that set out in Annex 8 of UN Regulation 118, a result that has, thus far, eluded the fire retardant textile industry. In addition, the fire barrier cloth provides a single textile, that is padded but sufficiently pliable to be utilized in conventional upholstery methods (without requiring the multiple additional steps that would be required to integrate multiple layers of fabric into a single seat), and that offers an environmentally-friendly and commercially-viable solution to a long-standing problem within the industry. It will be appreciated by a person skilled in the art, from the foregoing description, that modifications and variations could be made to the described embodiments, without departing from the scope of the invention as defined by the appended claims. It will be understood from the above description that each layer of the integrated fire barrier cloth meets, in itself, certain fire levels and regulations, but the inventor has determined, through significant innovative effort, that by bonding the three types of material together, 5 the resultant fire barrier cloth (unexpectedly and surprisingly) does not just meet the individual fire levels of each layer, nor is it merely the sum of the individual parts, but also passes an entirely different fire safety test, namely that set out in Annex 8 of the UN Regulation R118, which is one of the most difficult fire levels to attain. Accordingly, the integrated fire barrier cloth described herein provides an integrated flexible textile 10 that offers significantly higher (and broader) fire levels than has previously been achieved.

Claims

1. An integrated fire barrier cloth comprising a first layer of flexible material that meets at least fire level Crib 7 and a second layer of flexible material that meets at least fire level BS5852 0 + 1, the first and second layers of material being permanently coupled together with a non flammable flexible material therebetween.

2. An integrated fire barrier cloth according to claim 1, wherein the non flammable material meets fire level FMVSS302.

3. An integrated fire barrier cloth according to claim 1 or claim 2, wherein said first layer of material comprises an interliner cloth.

4. An integrated fire barrier cloth according to claim 3, wherein said interliner cloth comprises one of natural wool and FR viscose, 100% wool, 100% FR viscose, polyester or polyester mix.

5. An integrated fire barrier cloth according to any of the preceding claims, wherein said second layer of material comprises a flexible thermosetting polymer layer.

6. An integrated fire barrier cloth according to claim 5, wherein said polymer layer comprises one or both of polyvinyl chloride and polypropylene.

7. An integrated fire barrier cloth according to any of claims 5 to 7, wherein said second layer of material comprises a flexible substrate carrying a layer of flexible thermosetting polymeric material.

8. An integrated fire barrier cloth according to claim 7, wherein said flexible substrate is a textile substrate and comprises or includes one or more of polyester, wool, viscose, melamine and halogen-containing fibres.

9. An integrated fire barrier cloth according to claim 8, wherein said textile substrate comprises 100% polyester spunbond.

10. An integrated fire barrier cloth according to claim 7, wherein said flexible substrate comprises a thermoplastic polymer.

11. An integrated fire barrier cloth according to any of claims 5 to 10, wherein at least one flame retardant chemical is incorporated in said thermosetting polymer material.

12. An integrated fire barrier cloth according to any of the preceding claims, comprising a flexible foam substrate bonded or otherwise coupled on one surface thereof to said first flexible layer of material and bonded or otherwise coupled on the opposing surface thereof with said second flexible layer of material.5 13. An integrated fire barrier cloth according to claim 12, wherein said foam is a highresilience foam.

14. An integrated fire barrier cloth according to claim 13, wherein said foam is a combustion modulated high resilience (CMHR) foam.

15. An integrated barrier cloth according to any of claims 12 to 14, wherein said foam 10 comprises polyurethane.

16. An integrated barrier cloth according to any of claims 12 to 15, wherein the thickness of said flexible foam layer is 2-10mm.A

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