METHOD FOR PRODUCING A HIGHLY ELASTIC FLAME-RESISTANT NON-WOVEN MEMBRANE LAMINATE, FLAME-RESISTANT NON-WOVEN MEMBRANE LAMINATE AND FLAME-RESISTANT PROTECTIVE CLOTHING

Description

[0001] The invention relates to a method for producing a flame-retardant nonwoven membrane laminate according to the preamble of claim 1, a flame-retardant nonwoven membrane laminate according to claim 6, and flame-retardant protective clothing according to claim 11.

[0002] Flame-retardant textile laminates and their use in flame-retardant protective clothing are already known from DE 202020102447 U1. Such protective clothing is used, for example, by firefighters, industrial workers who require protection against electric arcs, police, the military, and in motorsports. The choice of textile materials and membranes depends on the specific application of the textile laminate.

[0003] One of the material layers of the well-known textile laminate can be a non-woven material onto which a breathable, i.e., water vapor permeable, but waterproof membrane is laminated.

[0004] In the case of DE 202020102447 U1, the breathing and elasticity properties can be significantly improved by applying the adhesive used to join the material layers in the form of a hexagonal or triangular grid pattern.

[0005] For certain applications, however, it is desirable to have flame-retardant nonwoven membrane laminates available that possess particularly high elasticity and stretchability, as well as excellent recovery properties. These properties are especially important, for example, in head protection hoods, cuffs, or elastic inserts in flame-retardant protective clothing.

[0006] The invention is therefore based on the objective of creating a method for producing a flame-retardant nonwoven membrane laminate that exhibits particularly high elasticity and elongation as well as particularly good recovery properties. Furthermore, the invention aims to create a flame-retardant nonwoven membrane laminate and flame-retardant protective clothing made with such a nonwoven membrane laminate.

[0007] This problem is solved according to the invention by a method having the features of claim 1, a flame-retardant nonwoven membrane laminate according to claim 6, and flame-retardant protective clothing according to claim 11. Advantageous embodiments of the invention are specified in the further claims.

[0008] The method according to the invention is characterized by the following steps: Providing a flame-retardant nonwoven fabric, overstitching the nonwoven fabric with an elastic sewing thread using a stitch-knitting process or by quilting, wherein the elastic sewing thread is sewn to the nonwoven fabric in a stretched state, laminating a membrane onto the overstitched nonwoven fabric to form a nonwoven-membrane laminate, shrinking the nonwoven-membrane laminate by means of a blind dyeing or dyeing process in a dyeing machine or dyeing apparatus, wherein the nonwoven-membrane laminate passes through or remains in a bath in a loose, unstretched form, drying the shrunk nonwoven-membrane laminate under low tension, so that the shrunk and dried nonwoven-membrane laminate is elastically deformable between a contracted state and a stretched state and can be stretched from the stretched state to the contracted state by means of the elastic sewing thread. The condition is reversible.

[0009] The term "nonwoven fabric" is used in the present invention in the broadest sense and also includes, for example, fibrous filaments.

[0010] Surprisingly, it has been shown that by combining overstitching a flame-retardant nonwoven fabric with an elastic sewing thread, shrinking, in particular complete shrinkage, of the nonwoven fabric after lamination of the membrane under low-stress conditions using a bath in a blind dyeing or dyeing process, and subsequent drying of the shrunken nonwoven-membrane laminate under low-stress conditions, a flame-retardant nonwoven-membrane laminate with very high elongation, elasticity and excellent recovery behavior can be produced.

[0011] Preferably, the flame-retardant nonwoven fabric consists of one or more of the following materials: M-aramid, P-aramid, polyamide-imide, polyimide, polybenzimidazole, polybenzoxazole, modacrylic, melamine resin, viscose FR, modal FR, lyocell FR, cotton FR, cotton, viscose, modal, lyocell, aromatic PES, wool, polyamide, polyester. The nonwoven fabric can consist of one of the aforementioned materials or of a mixture of several of the aforementioned materials. In particular, the nonwoven fabric can consist of a mixture of cellulose fibers and modacrylic fibers. The flame retardancy can be an inherent property of the respective nonwoven fibers or achieved by appropriate finishing of the nonwoven fabric.

[0012] Preferably, the flame-retardant nonwoven fabric is a Maliv nonwoven, waterjet nonwoven, needle-punched nonwoven, or needle-punched felt. The nonwoven fabric can also be produced by chemical fiber bonding or by thermal fiber bonding through the incorporation and activation of bicomponent fibers.

[0013] A preferred embodiment of a flame-retardant nonwoven fabric according to the invention is a nonwoven fabric made of 40-60 wt.%, in particular 50 wt.%, meta-aramid and 60-40 wt.%, in particular 50 wt.%, viscose FR, wherein the nonwoven fabric has a basis weight of 80-120 g / m², in particular 100 g / m².

[0014] By overstitching the unshrunk nonwoven fabric with a pre-tensioned elastic thread, an overstitched nonwoven fabric is created, in which the thread exerts a contraction force on the nonwoven fabric, attempting to pull it together. Advantageously, the overstitching is carried out in such a way that the contraction forces act in a specific direction, particularly in the machine-length direction of the nonwoven fabric.

[0015] Preferably, the nonwoven fabric is overstitched with the elastic sewing thread using the Maliwatt method. The Maliwatt method is a stitch-knitting process in which loops are formed by means of a multitude of parallel, embedded knitting threads, resulting in mechanical bonding of the nonwoven fabric. In the method according to the invention, an elastic sewing thread is used as the knitting thread, which is stitched to the nonwoven fabric in a stretched state, i.e., with a specific pre-tension. The nonwoven fabric preferably consists of a cross-laid staple fiber nonwoven or spunbond nonwoven.

[0016] It is also conceivable to overstitch the non-woven fabric using elastic sewing thread by means of quilting.

[0017] The elastic sewing thread is preferably made of elastane (spandex) or silicone.

[0018] In a preferred embodiment, a nonwoven fabric made of 50 wt.% meta-aramid and 50 wt.% viscose FR, which has a basis weight of 100 g / m², is overstitched with a 78 dtex elastane multifilament yarn in a tricot lay.

[0019] The membrane is laminated onto the overstitched nonwoven fabric. This lamination is carried out in such a way that subsequent contraction and stretching of the nonwoven-membrane laminate is not impeded. Since the membrane is a very thin, flexible sheet structure, it can also accommodate any subsequent shrinkage of the nonwoven fabric.

[0020] Laminating the membrane onto the overstitched nonwoven fabric is preferably carried out using an adhesive applied to the nonwoven fabric or membrane in the form of a grid pattern, hexagonal pattern, or triangular pattern. This creates adhesive-free areas, which are particularly advantageous with regard to the breathability, elasticity, and stretchability of the laminate. Other adhesive application methods are also readily possible.

[0021] Preferably, the membrane is a water vapor permeable, i.e., breathable, membrane made of polyurethane, polyester, polyether, ePTFE, polyurethane nanofibers, bicomponent polyether, or bicomponent ePTFE. Preferably, the membrane is waterproof.

[0022] The membranes can be produced in the usual way by a meltblown, electrospinning or nanospinning process, by stretching or drawing polymers such as PES, PET or PTFE, or in a single-coat or multi-coat process, for example on a polyurethane basis.

[0023] It is readily possible to laminate one or even several additional textile layers onto the nonwoven fabric before shrinking, provided these layers are capable of undergoing the desired wash shrinkage. Laminating the additional textile layer(s) can be done before or after laminating the membrane. The additional textile layer(s) can be made of the same or a different material as the nonwoven fabric.

[0024] The shrinkage of the overstitched nonwoven membrane laminate is achieved by means of a blind dyeing or dyeing process in a dyeing machine or dyeing apparatus. Such a blind dyeing or dyeing process, through the specific combination of complete saturation of the nonwoven fabric with a dye bath, the temperatures typically prevailing in dyeing machines or dyeing apparatus, the mechanics used there, and the stress-free passage or immersion of the laminate in the dye bath, enables particularly effective shrinkage, especially complete shrinkage, of the laminate.

[0025] Shrinking the laminate eliminates internal stresses. The elastic sewing thread, due to its pre-tension, causes or supports this shrinking or contraction of the laminate.

[0026] To achieve high elasticity and stretchability of the nonwoven membrane laminate, the laminate preferably exhibits a washing shrinkage of at least 15% in the longitudinal and / or transverse direction before shrinkage. This makes it possible to elastically stretch the laminate by a factor corresponding to the washing shrinkage, i.e., by at least 15%, after it has fully shrunk.

[0027] The measurement of washing shrinkage is carried out according to DIN EN ISO 5077.

[0028] Preferably, the shrinkage of the nonwoven membrane laminate is carried out in a reel or a jet dyeing machine, wherein the nonwoven membrane laminate passes through the bath in a loose, unstretched form.

[0029] The subsequent drying of the shrunken nonwoven membrane laminate is carried out with minimal tension, i.e., in a loose, unstretched state, avoiding internal stresses as much as possible. Drying can be performed, for example, on a tensioning frame with minimal tension and maximum lead time.

[0030] Using the method according to the invention, a flame-resistant nonwoven membrane laminate is created which is characterized by particularly high stretchability and elasticity and particularly good recovery behavior.

[0031] The nonwoven membrane laminate according to the invention is particularly suitable for use in flame-retardant protective clothing, for example, for head protection hoods, cuffs, and elastic inserts in protective garments. Such protective clothing is used particularly by fire departments, industry, authorities, and in motorsports.

[0032] Preferably, the protective clothing has a loose layer of a flame-retardant textile material covering the membrane of the flame-retardant nonwoven membrane laminate. This loose layer covers the membrane side of the laminate, thus protecting the membrane and improving the comfort and moisture management of the protective clothing. In particular, the loose layer absorbs and buffers perspiration so that it can be released through the membrane in the form of water vapor. Furthermore, the loose layer can have special properties such as increased temperature resistance.

[0033] The loose layer is preferably only connected to the nonwoven membrane laminate at the main seams of the protective clothing.

[0034] The loose layer can consist of any of the fibers or fiber mixtures mentioned in connection with the flame-retardant nonwoven fabric. Preferably, the loose layer therefore consists of one or more of the following materials: M-aramid, P-aramid, polyamide-imide, polyimide, polybenzimidazole, polybenzoxazole, modacrylic, melamine resin, viscose FR, modal FR, lyocell FR, cotton FR, cotton, viscose, modal, lyocell, aromatic PES, wool, polyamide, polyester. The loose layer can consist of one of the aforementioned materials or of a mixture of several of the aforementioned materials. In particular, the loose layer can consist of a mixture of cellulose fibers and modacrylic fibers. The flame retardancy can be an inherent property of the respective fibers or achieved by appropriate finishing of the loose layer.

Claims

1. Method for the production of a low-flammability non-woven-fabric membrane laminate, characterised by the following steps: - providing a low-flammability non-woven fabric, - sewing over the non-woven fabric with an elastic stitch by means of a stitch-bonding method or by means of stitching, wherein the elastic stitch is sewn together with the non-woven fabric in a stretched state, - laminating a membrane onto the sewn-over non-woven fabric to produce a non-woven-fabric membrane laminate, - pre-shrinking the non-woven-fabric membrane laminate by means of a blind dyeing or dyeing process in a dyeing machine or in a dyeing appliance, wherein, in a dry, untensioned state, the non-woven-fabric membrane laminate passes through, or remains within, a bath, - low-tension drying of the pre-shrunk non-woven-fabric membrane laminate, such that the pre-shrunk and dried non-woven-fabric membrane laminate can be elastically deformed between a contracted state and a non-contracted state, and can be returned from the non-contracted state into the contracted state by means of the elastic stitch.

2. Method according to claim 1, characterised in that the sewing-over of the non-woven fabric with the elastic stitch is carried out by means of the Maliwatt method.

3. Method according to claim 1 or 2, characterised in that the lamination of the membrane onto the sewn-over non-woven-fabric is carried out by means of an adhesive that is applied to the non-woven fabric or the membrane by in the form of a grated pattern, hexagonal pattern or triangular pattern.

4. Method according to one of the preceding claims, characterised in that the non-woven-fabric membrane laminate has, prior to the pre-shrinking, a washing shrinkage level of at least 15%.

5. Method according to one of the preceding claims, characterised in that the pre-shrinking of the non-woven-fabric membrane laminate is carried out in a winch dyeing machine or a jet dyeing machine.

6. Low-flammability non-woven-fabric membrane laminate produced according to a method according to claims 1 to 5.

7. Non-woven-fabric membrane laminate according to claim 6, characterised in that the low-flammability non-woven-fabric consists of one or more of the following materials: M-aramid, P-aramid, polyamidoamide, polyimide, polybenzimidazole, polybenzoxazole, modacrylic, melamine resin, viscose-FR, modal-FR, lyocell-FR, cotton-FR, cotton, viscose, modal, lyocell, aromatic PES, wool, polyamide, polyester.

8. Non-woven-fabric membrane laminate according to claim 6 or 7, characterised in that the low-flammability non-woven fabric is a Malivlies, hydro-entangled non-woven fabric, needle felt, needled non-woven fabric, a non-woven fabric produced by chemical fibre bonding or a non-woven fabric produced by thermal fibre bonding, by means of mixing in and activating bicomponent fibres.

9. Non-woven-fabric membrane laminate according to one of claims 6 to 8, characterised in that the elastic stitch consists of elastane or silicone.

10. Non-woven-fabric membrane laminate according to one of claims 6 to 9, characterised in that the membrane is a breathable, water-vapour-permeable membrane that consists of polyurethane, polyester, polyether, ePTFE, polyurethane nanofibres, bicomponent polyether or bicomponent ePTFE.

11. Low-flammability protective clothing having a low-flammability non-woven-fabric membrane laminate according to one of claims 6 to 10.

12. Low-flammability protective clothing according to claim 11, characterised in that the membrane of the non-woven-fabric membrane laminate is covered by a loose layer made from a low-flammability textile material.

13. Low-flammability protective clothing according to claim 12, characterised in that the loose layer made from a low-flammability textile material consists of one or more of the following materials: M-aramid, P-aramid, polyamidoamide, polyimide, polybenzimidazole, polybenzoxazole, modacrylic, melamine resin, viscose-FR, modal-FR, lyocell-FR, cotton-FR, cotton, viscose, modal, lyocell, aromatic PES, wool, polyamide, polyester.