FLAME-RESISTANT FINISH OR COATING

Abstract

A flame-resistant finish is adapted for a closure piece to form a detachable closure. The closure piece has a flat basic fabric (14) of warp threads (10), and weft threads (12). Functional elements (18) protrude on the front side of the basic fabric (14). The basic fabric (14) is provided with the flame-resistant finish. The fabric (14) and the functional elements (18) are predominantly, preferably entirely, made of flame-resistant plastic materials.

Claims

1. A flame-resistant finish for a flame-resistant closure piece that is adapted to a corresponding closure piece to form a detachable closure and that has at least one flat basic backing and functional elements protruding on a front side of the basic backing, the flame-resistant finish comprising: a solvent-free, moisture-curing, reactive polyurethane prepolymer-based melt adhesive.

2. A flame-resistant finish according to claim 1 wherein said melt adhesive additionally contains 10 to 90% polyester-polyol, 0 to 50% polyether-polyol, 5 to 35% polyisocyanate, 2 to 50% flame-retardant agents of at least one of antimony-free and halogen-free phosphorus compounds or triazine compounds, and additives of catalyst or a stabilizer as needed.

3. A flame-resistant finish according to claim 1 wherein said melt adhesive includes polyester-polyol therein.

4. A flame-resistant finish according to claim 1 wherein said melt adhesive includes polyether-polyol therein.

5. A flame-resistant finish according to claim 2 wherein said flame-retardant agents comprise antimony-free and halogen-free phosphorus compounds.

6. A flame-resistant finish according to claim 2 wherein said flame-retardant finish comprises triazine compounds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Referring to the drawings that form a part of this disclosure and that are schematic and not to scale:

[0040] FIG. 1 is a top perspective view of a fabric structure of a contact closure piece according to an exemplary embodiment of the invention; and

[0041] FIG. 2 is a side view of the flat contact closure piece of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0042] FIG. 1 shows a view from above of a portion of a flat contact closure piece that can be extended ad infinitum within the image plane in either image direction. The geometric dimensions of the woven fabric depend upon the specifications of the weaving machine on which the closure piece is produced. In particular, these closure pieces are packaged for later use as rolls of contact closure tape (not illustrated).

[0043] The closure piece has warp threads 10 and weft threads 12, which threads are transversely interwoven to form the basic fabric 14 for the contact closure piece. Furthermore, in the basic fabric 14, functional threads 16 are provided in the form of pile threads, which form a further component of the basic fabric 14. The respective functional thread 16 then forms the individual functional or closure elements 18 for the flat contact closure piece, which shall be explained in more detail in the following. Furthermore, rather than threads the technical term yarns is often used.

[0044] An arrow 20 indicating the production direction for the closure piece to be manufactured is visible on the top side of FIG. 1. In the arrangement shown according to FIG. 1, the respective weft threads 12 are arcuately configured in the nature of a sine or a cosine wave. The warp threads 10 extend parallel to the production direction 20 and parallel to each other in a rectilinear arrangement at the intersections between warp threads 10 and weft threads 12. In the embodiment shown in FIG. 1, only the weft threads 12 are in an arcuately extending arrangement in the basic fabric 14. In an alternating sequence, the respective weft thread 12 passes over a warp thread 10 and passes under the next consecutive one. The advantages of such an arcuate configuration are explained in more detail in document DE-B-102 40 986 of the patent holder and therefore shall not be discussed any further here.

[0045] The functional or pile thread 16 forms a loop 22 above each place where it passes under the basic fabric 14, and then forms another loop 24 immediately afterwards, thus creating a V-binding. However, other types of binding are conceivable here, such as a W-binding or other similar binding of the functional thread 16.

[0046] The loops 22, 24 form a type of closure elements 18. If the loops 22, 24 remain closed as shown in FIG. 1, a fleece-type contact closure piece arises in which hook or mushroom-type closure elements 28 can engage in these loops 22, 24 in such a way as to obtain a releasable contact closure as part of a closure or fastening system as a whole. However, as illustrated in FIG. 2 it is also possible to cut the loops 22, 24 open along a dividing line 26 in such a way that, after melting the free ends of the opened loop, in each case a mushroom-shaped closure element 28 is formed. The mushroom-shaped closure elements 28 can then be hooked in a releasable manner with corresponding fleece material of another closure piece, not illustrated in any greater detail here, which serves as the other closure piece.

[0047] As further shown in the illustration of FIG. 2, an individual weft thread 12 can also be a weft thread pair or be multi-threaded. The same is true for the warp threads 10, which according to the cross sectional or schematic view of FIG. 2, in each case pass over a pair of weft threads 12 of the second closure piece and subsequently pass under this pair of weft threads 12 in alternating sequence. The respective functional or pile thread 16, skipping a weft thread pair 12 in each case, passes over the next two weft thread pairs 12 in the sequence shown. Hence the loops of a first kind 22 and of another kind 24 are arranged offset relative to each other on the basic fabric 14. The loops of the first kind 22 form essentially closed O-shaped loops. The loops of the second kind 24 are V-shaped or U-shaped in configuration. A repeating pattern for a function thread 16 therefore repeats itself in the direction of the weft threads 10 after five warp threads 10. To arrive at a flame-resistant or flame-retardant closure piece, the closure piece according to FIGS. 1 and 2 is constructed as described in greater detail in the following. The warp threads 10 and the weft threads 12 are thus formed from PA66 plastic materials, which in this case are monofilament polyamide threads or yarns. The thread or yarn systems are provided with a flame-retardant additive, in particular in the form of a phosphorus compound. The flame-retardant mechanism acts in the gas phase in particular. The effect is permanent and wash-resistant. In the PA66 thread system, use is made of an intrinsically flame-retardant polyamide fiber that does not contain any halogens. The textile properties of the PA fiber are not negatively impacted by the flame-retardant additive, and the fiber turns out to be high-strength. The polyamide-66 fiber in particular fulfills the specifications of DIN 4102-1, B1).

[0048] The pile threads 16, which as explained will eventually form the functional elements, are formed of PP plastic materials. The PP fibers are marketed under the brand name LIFOFLAM 70/101 PP. The polypropylene fiber is also high-strength and has a flame-retardant agent in the form of a suitable phosphorus compound.

[0049] Triazine compounds and/or thread systems containing graphite or other carbon constituents can also be used as flame-retardant additives in lieu of the aforementioned phosphorus compounds.

[0050] To provide the basic fabric 14 with a secure attachment and in particular to prevent the pile threads 16 from being pulled out of the basic fabric 14 under load, advantageously the basic fabric 14 is provided with a finish 30. In particular, the finish 30 is applied in such a way that all threads in the basic fabric system are coated with the finish 30.

[0051] Using a finish 30 with self-adhesive properties for the basic fabric 14 has proven to be particularly advantageous.

[0052] Experiments with a finish 30 of a polyurethane aqueous dispersion such as the one marketed under the trade name TUBICOAT PUS, with added flame-retardant agents such as those marketed under the brand names Apyrol PA1 and Apyrol PA2, result in very short burning distances and very short flame persistence compared to comparably configured hook and loop closure systems without such flame retardants added, especially in the FAR vertical burn test.

[0053] The following formula for the finish 30 binding the basic fabric has proven to be particularly suitable:

TABLE-US-00001 Apyrol PA1 7% Apyrol PA2 7% Tubicoat PUS 40% Water 46% MgCl.sub.2 0.01%.

[0054] If an additional adhesive layer is to be applied preferably on the exposed bottom side of the finish 30, this layer is artificial rubber-based or acrylate-based. In the latter case, the acrylate is practical to be constituted as an aqueous dispersion and to add a flame-retardant agent to it, which agent is marketed under the trade name Apyrol PP46 and contains ammonium salts in addition to polyphosphoric acids. To be able to bind the basic fabric 14 provided with a finish 30 with third components, provision can be made such that an additional adhesive layer 32 is applied to the bottom side of the finish 30 facing away from the protruding functional elements 18. This adhesive layer 32, which is applied to the finish 30 like a coating, can be, for example, a flame-resistant pressure-sensitive adhesive or adhesive system. If the adhesive layer 32 is covered by a suitable paper material (not illustrated) on the surface exposed to the surroundings, the closure piece can be set directly on third components after the cover paper on the adhesive layer 32 is removed.

[0055] However, constituting the finish 30 from a solvent-free, moisture-curing, reactive polyurethane prepolymer-based melt adhesive has proven to be particularly advantageous from a flame retardancy standpoint. Such a polyurethane melt adhesive is marketed under the brand name AdtraPUR F 9131-UV. The finish to be applied like a coating for the basic fabric 14 should in particular be applied at the rate of between 40 to 200 g/m.sup.2, preferably 120 g/m.sup.2. The particularly preferred finish to apply has the following formula: [0056] 10 to 90% polyester-polyol, [0057] 0 to 50% polyether-polyol, [0058] 5 to 35% polyisocyanate, [0059] 2 to 50% flame-retardant agent such as antimony- and halogen-free phosphorus compounds and/or triazine compounds, and [0060] additives such as catalysts and stabilizers, as needed.

[0061] In this regard, particular mention is made of UV stabilizers and antioxidants, which owing to their low concentration cannot negatively impact the process parameters during the manufacturing of the closure piece.

[0062] For the average skilled professional in the field of contact closure technology, it is surprising that, with the coating-like finish 30 evenly applied subsequently to a finished, non-flame retardant hook and loop closure piece that can also be cast, surprisingly the standard flame-resistance requirements of the aircraft industry cannot only be fulfilled, but that furthermore the recently required composite test will also be passed. For instance, if the hook and loop closure with its one closure piece is sewn on in the form of a textile sheeting material that serves as, say, a curtain or a seat cover, it is no longer sufficient just to document the flame resistance of the contact closure piece. Instead, the composite as a whole must be tested for flame resistance. Owing to the finish 30 presented herein, such composite tests can be performed effortlessly and successfully, provided that the corresponding closure pieces and/or the textile basic material of the composite partner are likewise configured as flame-resistant.

[0063] In spite of the relatively high concentration of flame retardant agents, the wash fastness of the entire closure system is retained even at very high temperatures, for example in the context of 95 C. hot washes. The stringent conditions for the use of chemicals are assuredly fulfilled. The European standards and directives currently in effect are fulfilled with the finish system described above.

[0064] Overall, the criteria listed for the individual flame resistance tests can be more than adequately fulfilled with a closure piece equipped or provided with the aforementioned materials. Practical experiments have shown that compared to prior art systems, the flame persistence, the components of the closure piece dripping off under heat, and the measured burning distance can be reduced considerably, if need be to virtually zero.

[0065] While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the claims.