Flameproof textile surface structures

[0001] The present invention relates to textile fabrics comprising

[0002] A) from 20 to 90% by weight of melamine fiber A), and

[0003] B) from 10 to 80% by weight of flame resistant polyester fiber B).

[0004] The present invention further relates to the use of these textile fabrics for manufacturing heat protective clothing and flame protective clothing and to the use of these textile fabrics in vehicles and spaces at risk from fire.

[0005] Flame resistant wovens and nonwovens are used in heat and flame protective clothing but also in vehicles and spaces at risk from fire, for example as a fire guard in the upholstery of seats, as flame resistant mattress covers, wallcovers and wallpapers. Owing to the severe mechanical stress encountered for example in the case of seat cushions in public transit means and airplanes or in the case of wallcoverings in movie houses and theatres, the wovens and nonwovens shall be durable and abrasion resistant.

[0006] Seat upholstery, wallcoverings, wallpapers and other fixed textiles are customarily cleaned or reconditioned in place; flame protective clothing is washed in industrial washing machines. The woven and nonwoven fabrics have to be resistant to this severe physical stress.

[0007] Flame protective fibers such as those based on aramid (for example Twaron® from Akzo-Nobel, Kevlar® and Nomex® from DuPont, Technora® from Teijin) exhibit good heat and flame protection, but are so harsh as to offer poor wear comfort when used in clothing or an unpleasant hand when used in a fixed application, for example in seat covers. Moreover, they possess inadequate wear resistance.

[0008] EP-A 874 079 discloses heat and flame protective wovens comprising a blend of melamine fibers and aramid fibers.

[0009] DE-A 195 23 081 discloses blends of 10 to 90 parts by weight of melamine fibers and 10 to 90 parts by weight of natural fibers and also fabrics woven therefrom.

[0010] DE-A 196 17 634 discloses flame resistant fabrics woven from melamine fibers, optionally flame resistant fibers and normally flammable fibers such as wool, cotton, polyamide, polyester and viscose. Flame resistant polyesters are not mentioned.

[0011] EP-A 976 335 discloses fabrics woven from 10 to 90% by weight of cotton fibers, 5 to 45% by weight of polyamide or polyester fibers and 5 to 45% by weight of melamine fibers. The examples utilize normal (non flame resistant) polyester fiber.

[0012] The performance profile of these prior art wovens is unsatisfactory. More particularly, the abrasion resistance is inadequate and the resistance to cleaning operations is not always satisfactory.

[0013] It is an object of the present invention to remedy the aforementioned disadvantages. It is a particular object to provide textile fabrics combining good flame and heat protection, good wear comfort and pleasant hand.

[0014] It is a further object to provide textile fabrics which provide good flame protection even after numerous cleaning and conditioning operations. The textile fabrics shall lastly possess high abrasion resistance and be environmentally compatible.

[0015] We have found that these objects are achieved by the textile fabrics defined at the beginning and by the uses defined at the beginning. Preferred embodiments of the invention are revealed in subclaims.

[0016] None of the prior art documents cited discloses or suggests using flame resistant polyester fibers together with melamine fibers.

[0017] As used herein, “textile fabrics” comprehends all sheetlike textile articles, whatever their method of production. Useful textile fabrics accordingly include for example wovens, formed-loop knits, drawn-loop knits, tufteds, felts and nonwovens.

[0018] As to “flame resistant”, some preliminary remarks may be in order. To test the fire performance or flame resistance of a material, the material is exposed to an external source of ignition, for example a flame, under defined conditions, for example type, size, geometry and arrangement of the sample and the flame, flame temperature, duration of flaming. The source of ignition is removed and the behavior of the material is observed, for example slow or rapid burning, self-extinguishing, burning or melting drips, glowing, evolution of toxic gases, smoke evolution, etc.

[0019] By “flame resistant” is meant that the material—the fiber or fabric—is incombustible or continues to burn only very slowly or is self-extinguishing.

[0020] Flame resistance can be inherent to the chemical composition of the fiber or the construction of the textile fabric. This is the case with aramid fibers or glass fibers for example. Similarly, for example in the case of flame resistant polyester fibers, flame resistance can be attained through treatment of the fibers, of the yarn or of the textile fabric with a flame retardant or—often preferred—by using a flame retardant in the course of the production of the fiber. For example, the flame retardant may be incorporated into the fiber as the fiber is being made.

[0021] Useful flame retardants include in particular reactive phosphorus compounds, for example Afflamit®, Pyrovatex®, Proban® or Secan®.

[0022] The textile fabrics of the invention comprise

[0023] A) from 20 to 90%, preferably from 30 to 70% and particularly preferably from 40 to 60% by weight of melamine fibers A), and

[0024] B) from 10 to 80%, preferably from 30 to 70% and particularly preferably from 40 to 60% by weight of flame resistant polyester fiber B).

[0025] Melamine Fiber A)

[0026] The melamine fiber used according to the invention may be produced for example according to the processes described in EP-A 93 965, DE-A 23 64 091, EP-A 221 330 or EP-A 408 947. Particularly preferred melamine fiber includes as monomeric building block (A) from 90 to 100 mol % of a mixture consisting essentially of from 30 to 100, preferably from 50 to 99, particularly preferably from 85 to 95, especially from 88 to 93, mol % of melamine and from 0 to 70, preferably from 1 to 50, particularly preferably from 5 to 15, especially from 7 to 12, mol % of a substituted melamine I or mixtures of substituted melamines I.

[0027] As further monomer building block (B) the particularly preferred melamine fiber contains from 0 to 10, preferably from 0.1 to 9.5, especially from 1 to 5, mol %, based on the total number of moles of monomeric building blocks (A) and (B), of a phenol or of a mixture of phenols.

[0028] The particularly preferred melamine fiber is customarily obtainable by reacting components (A) and (B) with formaldehyde or formaldehyde-supplying compounds and subsequent spinning, the molar ratio of melamines to formaldehyde being in the range from 1:1.15 to 1:4.5, preferably in the range from 1:1.8 to 1:3.0.

[0029] Useful substituted melamines of the general formula I

[0030] include those where X1, X2 and X3 are each selected from the group consisting of —NH2, —NHR1 and —NR1R2, subject to the proviso that X1, X2 and X3 are not all —NH2, and R1 and R2 are each selected from the group consisting of hydroxy-C2-C10-alkyl, hydroxy-C2-C4-alkyl-(oxa-C2-C4-alkyl)n, where n is from 1 to 5, and amino-C2-C12-alkyl.

[0031] Hydroxy-C2-C10-alkyl is preferably hydroxy-C2-C6-alkyl, such as 2-hydroxyethyl, 3-hydroxy-n-propyl, 2-hydroxyisopropyl, 4-hydroxy-n-butyl, 5-hydroxy-n-pentyl, 6-hydroxy-n-hexyl, 3-hydroxy-2,2-dimethylpropyl, preferably hydroxy-C2-C4-alkyl, such as 2-hydroxyethyl, 3-hydroxy-n-propyl, 2-hydroxyisopropyl and 4-hydroxy-n-butyl, particularly preferably 2-hydroxyethyl and 2-hydroxyisopropyl.

[0032] Hydroxy-C2-C4-alkyl-(oxa-C2-C4-alkyl)n preferably has n from 1 to 4, particularly preferably n 1 or 2, such as 5-hydroxy-3-oxapentyl, 5-hydroxy-3-oxa-2,5-dimethylpentyl, 5-hydroxy-3-oxa-1,4-dimethylpentyl, 5-hydroxy-3-oxa-1,2,4,5-tetramethylpentyl, 8-hydroxy-3,6-dioxaoctyl.

[0033] Amino-C2-C12-alkyl is preferably amino-C2-C8-alkyl, such as 2-aminoethyl, 3-aminopropyl, 4-aminobutyl, 5-aminopentyl, 6-aminohexyl, 7-aminoheptyl and 8-aminooctyl, particularly preferably 2-aminoethyl and 6-aminohexyl, very particularly preferably 6-aminohexyl.

[0034] Particularly useful substituted melamines for the invention include the following compounds: 2-hydroxyethylamino-substituted melamines such as 2-(2-hydroxyethylamino)-4,6-diamino-1,3,5-triazine, 2,4-di(2-hydroxyethylamino)-6-amino-1,3,5-triazine, 2,4,6-tris(2-hydroxyethylamino)-1,3,5-triazine; 2-hydroxyisopropylamino-substituted melamines, such as 2-(2-hydroxyisopropylamino)-4,6-diamino-1,3,5-triazine, 2,4-di(2-hydroxyisopropylamino)-6-amino-1,3,5-triazine, 2,4,6-tris(2-hydroxyisopropylamino)-1,3,5-triazine; 5-hydroxy-3-oxapentylamino-substituted melamines, such as 2-(5-hydroxy-3-oxapentylamino)-4,6-diamino-1,3,5-triazine, 2,4-di(5-hydroxy-3-oxapentylamino)-6-amino-1,3,5-triazine, 2,4,6-tris(5-hydroxy-3-oxapentylamino)-1,3,5-triazine, 6-aminohexylamino-substituted melamines, such as 2-(6-aminohexylamino)-4,6-diamino-1,3,5-triazine, 2,4-di(6-aminohexylamino)-6-amino-1,3,5-triazine, 2,4,6-tris(6-aminohexylamino)-1,3,5-triazine; or mixtures thereof, for example a mixture of 10 mol % of 2-(5-hydroxy-3-oxapentylamino)-4,6-diamino-1,3,5-triazine, 50 mol % of 2,4-di(5-hydroxy-3-oxapentylamino)-6-amino-1,3,5-triazine and 40 mol % of 2,4,6-tris(5-hydroxy-3-oxapentylamino)-1,3,5-triazine.

[0035] Useful phenols (B) include phenols that contain one or two hydroxyl groups and may be substituted by radicals selected from the group consisting of C1-C9-alkyl and hydroxyl, and also C1-C4-alkanes substituted by two or three phenol groups, di(hydroxyphenyl) sulfones, or mixtures thereof.

[0036] Preferred phenols are: phenol, 4-methylphenol, 4-tert-butylphenol, 4-n-octylphenol, 4-n-nonylphenol, pyrocatechol, resorcinol, hydroquinone, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl) sulfone, particularly preferably phenol, resorcinol and 2,2-bis(4-hydroxyphenyl)propane.

[0037] Formaldehyde is generally used as an aqueous solution having a concentration of, for example, from 40 to 50% by weight or in the form of compounds supplying formaldehyde in the course of the reaction with (A) and (B), for example as oligomeric or polymeric formaldehyde in solid form such as paraformaldehyde, 1,3,5-trioxane or 1,3,5,7-tetroxocane.

[0038] The particularly preferred melamine fiber is customarily produced by polycondensing melamine, optionally substituted melamine and optionally phenol together with formaldehyde or formaldehyde-supplying compounds. All the components may be added from the start or may be reacted a little at a time and successively and the precondensates formed may have further melamine, substituted melamine or phenol added to them subsequently.

[0039] The polycondensation is carried out in a conventional manner (see EP-A 355 760, Houben-Weyl, Vol. 14/2, p. 357 ff).

[0040] The reaction temperature is generally in the range from 20 to 150° C., preferably in the range from 40 to 140° C. The reaction pressure is generally not critical. The reaction is generally carried out in the range from 100 to 500 kPa, preferably under atmospheric pressure.

[0041] The reaction can be carried out with or without solvent. Generally, no solvent is added when using aqueous formaldehyde solution. When formaldehyde bound in solid form is used, it is customary to use water as solvent, the amount used being generally within the range from 5 to 40%, preferably from 15 to 20%, by weight based on the total amount of monomers used.

[0042] The polycondensation is generally carried out in the pH range above 7. The pH range from 7.5 to 10.0 is preferred and that from 8 to 9 is particularly preferred.

[0043] The reaction mixture may further include small amounts of customary additives, such as alkali metal sulfites, eg. sodium disulfite and sodium sulfite, alkali metal formates, eg. sodium formate, alkali metal citrates, eg. sodium citrate, phosphates, polyphosphates, urea, dicyandiamide or cyanamide. They may be added as pure individual compounds or as mixtures with each other, in each case without a solvent or as aqueous solution, before, during or after the condensation reaction.

[0044] Other modifiers are amines and aminoalcohols, such as diethylamine, ethanolamine, diethanolamine or 2-diethylaminoethanol.

[0045] Useful additives further include fillers and emulsifiers. Useful fillers include for example fibrous or pulverulent inorganic reinforcing agents or fillers, such as glass fiber, metal powder, metal salts or silicates, for example kaolin, talc, baryte, quartz or chalk, pigments and dyes. Emulsifiers used are generally the customary nonionic, anionic or cationic organic compounds having long-chain alkyl moieties.

[0046] The polycondensation can be carried out batchwise or continuously, for example in an extruder (see EP-A 355 760), according to conventional methods.

[0047] To produce fiber the melamine resin of the invention is generally spun in a conventional manner, for example after addition of a curing agent, customarily acids, such as formic acid, sulfuric acid or ammonium chloride, at room temperature in a rotospinning machine and subsequently curing the crude fiber in a heated atmosphere or by spinning in a heated atmosphere, simultaneously evaporating the water solvent and curing the condensate. Such a process is described in detail in DE-A-23 64 091.

[0048] However, melamine fiber can also be produced using other customary methods, for example fiber pulling, extrusion and fibrillation. The fiber obtained is generally predried, optionally drawn and then cured at from 120 to 250° C.

[0049] The fiber is typically from 5 to 25 μm in thickness and from 2 to 2000 mm in length. Useful melamine resins are, for example, commercially available from BASF as Basofil®.

[0050] Polyester Fiber B)

[0051] Polyesters are homopolymers, copolymers, blends and graft polymers of synthetic long-chain polyesters that contain recurring ester groups in the polymer main chain as an essential constituent. Preferred polyesters are esters of an aromatic dicarboxylic acid with an aliphatic dihydroxy compound, i.e., polyalkylene arylates such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT).

[0052] Such polyalkylene arylates are obtainable by esterifying or transesterifying an aromatic dicarboxylic acid or its esters or ester-forming derivatives with a molar excess of an aliphatic dicarboxy compound and polycondensing the resultant esterification or transesterification product in a known manner.

[0053] Preferred dicarboxylic acids are 2,6-naphthalenedicarboxylic acid, terephthalic acid and isophthalic acid or mixtures thereof. Up to 30 mol % and preferably not more than 10 mol % of the aromatic dicarboxylic acids may be replaced by aliphatic or cycloaliphatic dicarboxylic acids such as adipic acid, azeleic acid, sebacic acid, dodecanedioic acids and cyclohexanedicarboxylic acids.

[0054] Preferred aliphatic dihydroxy compounds are diols having 2 to 6 carbon atoms, especially 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-hexanediol, 5-methyl-1,5-pentanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and neopentyl glycol or mixtures thereof.

[0055] Particularly preferred polyesters are polyalkylene terephthalates derived from alkanediols having 2 to 10 and preferably 2 to 6 carbon atoms. Of these, particular preference is given to polyethylene terephthalate and polybutylene terephthalate or blends thereof.

[0056] Preference is further given to polyethylene terephthalates and polybutylene terephthalates which contain up to 1% by weight, based on the polyesters, preferably up to 0.75% by weight, of 1,6-hexanediol and/or 5-methyl-1,5-pentanediol as further monomer units.

[0057] Such polyalkylene terephthalates are known per se and are described in the literature. They contain in the main chain an aromatic ring derived from the aromatic dicarboxylic acid. The aromatic ring may be substituted, for example by halogen such as chlorine and bromine or by C1-C4-alkyl groups such as methyl, ethyl, i-propyl, n-propyl, n-butyl, i-butyl or t-butyl.

[0058] The reaction is customarily carried out using a molar excess of diol in order that the ester equilibrium may be influenced in the desired form. The molar ratio of dicarboxylic acid or ester:diol is customarily in the range from 1:1.1 to 1:3.5 and preferably in the range from 1:1.2 to 1:2.2. Very particular preference is given to a dicarboxylic acid:diol molar ratio of from 1:1.5 to 1:2 and to a diester:diol molar ratio of from 1:1.2 to 1.5.

[0059] However, it is also possible to conduct the ester reaction using a smaller excess of diol in a first temperature zone and to correspondingly add further amounts of diol in subsequent temperature zones.

[0060] It may be advantageous to conduct the reaction in the presence of a catalyst. Preferred catalysts are titanium compounds and tin compounds as known inter alia from U.S. Pat. No. 3,936,421 and U.S. Pat. No. 4,329,444. Preferred compounds are tetrabutyl orthotitanate and triisopropyl titanate and also tin dioctoate.

[0061] Useful polyester fibers include all customary textile fibers composed of the aforementioned polyesters. Such fibers are known.

[0062] Polyester fibers are customarily produced by the melt spinning or the extrusion process, whereafter they are stretched hot. A subsequent heat treatment may be used to render them highly crystalline and shrinkage resistant. Details concerning polyester fibers may be found in Ullmanns Encyklopädie der Technischen Chemie, vol. 11, 4th edition, page 305, Verlag Chemie, Weinheim 1978, and Z. Rogowin's monograph, Chemiefasern, Thieme-Verlag, Stuttgart 1982, pages 259-285.

[0063] Useful polyester fibers include for example the commercially available Trevira® fibers from Trevira GmbH and Teretal® fibers from Montefibre.

[0064] In the case of wovens, the polyester fibers of the fill thread may be identical to or different from the polyester fibers of the warp thread. For instance, the fill may contain PET fibers and the warp PBT fibers, and vice versa.

[0065] According to the invention, the polyester fibers are flame resistant. The flame resistance is attained by treating the fibers and/or yarn with flame retardants or—preferably—by using flame retardants in the course of the production of the polyester fibers, i.e., the flame retardant is incorporated into the fiber as it is being made.

[0066] Useful flame retardants include reactive phosphorus compounds, for example Afflamit® from Thor Chemie, Pyrovatex® from Ciba, Proban® from Albright and Wilson, Secan® from Schumer. Polyphosphonates are also suitable. It is similarly possible to use halogen compounds, especially bromine compounds such as 2,2-bis(4,4′-hydroxyethoxy-3,5-dibromophenyl)propane, as flame retardants.

[0067] The treatment of the fibers or yarns with the flame retardants or the use of the flame retardants in the course of fiber production is effected in a conventional manner. The flame retardants are customarily used in a total amount of from 0.1 to 30% by weight, based on the flame resistant polyester fibers B) (that is, based on the sum total of normal, non flame resistant polyester fibers and flame retardant).

[0068] Flame resistant polyester fibers are commercially available for example as Trevira® CS from Trevira GmbH and as Dacron® from DuPont.

[0069] Flame Resistant Fibers C)

[0070] The textile fabrics of the invention, as well as melamine fibers A) and flame resistant polyester fibers B), may optionally further comprise up to 40% by weight of further flame resistant fibers C) other than polyester.

[0071] The proportion of the further flame resistant fibers C) is preferably up to 30% by weight and particularly preferably up to 25% by weight.

[0072] Useful further non polyester flame resistant fibers include in particular aramid fibers, flame resistant viscose fibers and flame resistant modacrylics.

[0073] Aramid fibers are preferably produced by spinning solutions of polycondensation products of iso- or terephthalic acid or derivatives thereof, such as acyl chlorides, with para- or meta-phenylenediamine in solvents, such as N-methylpyrrolidone, hexamethylenephosphoramide, concentrated sulfuric acid or customary mixtures thereof. The continuous fiber obtained is then customarily cut into staple fibers which are generally from 5 to 25 μm in thickness. Preferred aramid fibers are based on an isomeric poly-p-phenyleneterephthalamide (Kevlar®, U.S. Pat. No. 3,671,542) or poly-m-phenyleneisophthalamide (Nomex®, U.S. Pat. No. 3,287,324).

[0074] Viscose fibers are preferably spun from cellulose by the viscose process. Woodpulp cellulose is treated with caustic soda. The alkali cellulose obtained is squeezed off, comminuted and allowed to stand in air. The thus preripened alkali cellulose is treated with carbon disulfide CS2 to form cellulose xanthate. The xanthate is dissolved in dilute caustic soda to form a viscous dope known as viscose. The dope is filtered and stored. The thus afterripened dope is pumped through spinneret holes into a spin bath containing sulfuric acid, sodium sulfate and zinc sulfate, and the viscose coagulates to form fine cellulose filaments. The filaments are optionally stretched, then washed and aftertreated. Further details concerning viscose fibers are to be found in the aforementioned monograph by Z. Rogowin, pages 76-197.

[0075] Modacrylics are preferably obtained by straight-chain copolymerization of acrylonitrile with vinyl chloride or vinylidene chloride. The acrylonitrile fraction is in the range from 35 to 85% and especially in the range from 50 to 85% by weight. Further details concerning modacrylics are to be found in the monograph by Z. Rogowin, pages 293-313.

[0076] The viscose fibers and modacrylics are flame resistant. The flame resistance is attained by treating the fibers and/or yarn with flame retardants or—preferably—by using flame retardants in the course of the production of the fibers, i.e., the flame retardant is incorporated into the fiber as it is being made. Useful flame retardants include those mentioned in connection with the flame resistant polyester fibers B).

[0077] The treatment of the fibers or yarns with the flame retardants or the use of the flame retardants in the course of fiber production is effected in a conventional manner. The flame retardants are customarily used in a total amount of from 0.1 to 30% by weight, based on the flame resistant polyester fibers C) (that is, based on the sum total of normal, non flame resistant fibers and flame retardant).

[0078] Flame resistant viscose fibers are commercially available for example as viscose FR from Lenzing. Flame resistant modacrylics are available for example as Kanecar® SYCM from Kanebo Corp.

[0079] Non Flame Resistant Fibers D)

[0080] The textile fabrics of the invention, as well as the melamine fibers A), the flame resistant polyester fibers B) and the optional further flame resistant fibers C), may optionally further comprise up to 25% by weight of fibers D), which are not flame resistant.

[0081] The fraction of non flame resistant fibers D) is preferably up to 20% by weight and especially up to 10% by weight.

[0082] Useful non flame resistant fibers include all fibers, for example natural fibers and polyamide fibers.

[0083] The natural fibers used are generally naturally occurring fibers based on cellulose, such as cotton, wool, linen or silk, which natural fibers shall also comprehend cellulose-based fibers which are of natural origin but have been modified or treated by known and customary processes.

[0084] According to German Standard Specification DIN 60001, cotton and wool in particular are natural fibers, cotton belonging to the group of vegetable fibers. German Standard Specification DIN 60004 defines what is meant by the term wool. For the purposes of this invention, wool shall comprehend all coarse and fine animal hairs.

[0085] Useful polyamide fibers include all customary textile fibers composed of polyamide. Such fibers are known. Polyamide fibers are produced from various polyamide types, especially from small nylon 66 and nylon 6 and also from nylon 11 and nylon 610, by melt spinning or extrusion. Subsequently they are stretched hot or cold. Nylon 6 is polycaprolactam, nylon 66 is made up of hexamethylenediamine and adipic acid units. Nylon 11 is formed from 11 aminoundecanoic acids, nylon 610 from hexamethylenediamine and sebacic acid. Details concerning polyamide fibers are given in Ullmanns Encyklopädie der Technischen Chemie, volume 11, 4th edition, page 315, Verlag Chemie, Weinheim 1978.

[0086] Polyamide fibers are the preferred non flame resistant fibers D).

[0087] Useful polyamide fibers are commercially available for example from BASF, DuPont and Rhodia.

[0088] Making of Textile Fabrics

[0089] Examples of textile fabrics include wovens, formed-loop knits, drawn-loop knits, tufteds, felts and nonwovens.

[0090] The making of wovens, formed-loop knits, drawn-loop knits, tufteds, felts and nonwovens and of other textile fabrics is common knowledge and described for example in the monograph by W. Albrecht et al., Vliesstoffe, Verlag VCH, Weinheim 2000, expressly incorporated herein by reference.

[0091] The fibers are processed into an intimate blend into a conventional manner. The fiber blends are processed in a known manner, for example as described in the aforementioned monograph by Albrecht, section 4, pages 139 ff.

[0092] Wovens are generally produced from yarns. To produce yarns, the various fiber varieties are customarily preblended as a staple and spun into yarns using the known processes customary in the textile industry. These yarns can then be further processed into various kinds of wovens depending on the application.

[0093] Preference is given to textile fabrics selected from wovens and nonwovens. Particular preference is given to nonwovens.

[0094] Nonwovens and their production and also web-processing stitch bonding processes are described in Albrecht's aforementioned monograph.

[0095] A nonwoven is a sheetlike structure fabricated from fibers and consolidated in various ways. As used herein, the term “nonwovens” shall comprehend all sheetlike textile composites from fiber webs, especially consolidated fiber webs.

[0096] Nonwovens can be produced by Various processes, for example as dry laid webs, wet laid webs or spun bonded (extrusion) webs. See FIG. 4-1 on page 138 of Albrecht's monograph.

[0097] Dry laid webs can be produced for example by carding using a flat or roller card and superposing a plurality of card-produced films of fiber in a plurality of layers to form a web. They can similarly be produced by the aerodynamic process whereby the previously opened fibers are deposited by an air stream on a continuously moving foraminous surface through which the air is aspirated away on the other side.

[0098] Wet laid webs are produced in similar fashion to paper by dispersing the fibers in water, applying the suspension to a moving sieve belt, through which the water is filtered off to form the web, and subsequent consolidation of the web.

[0099] Spun bonded (extrusion) webs are produced from polymer chips, which are initially plasticated in an extruder before the resultant melt is spun into filaments. The filaments are stretched and laid down to form a web, which is then consolidated.

[0100] The consolidating can be effected for example using chemical means in the form of binders, which cause the fibers to adhere to each other. The chemical agents can be used continuously (by impregnation, coating, spraying, printing) or discontinuously.

[0101] Consolidation can also be effected thermally, for example by calendering, hot air consolidation or ultrasound. Thermal consolidation causes suitable fibers to melt incipiently and thus to cohere to each other. Lastly, consolidation can be effected mechanically (friction consolidation), for example by needling, interlooping, web stitching with or without thread or entangling.

[0102] Particularly preferred nonwovens are needled webs and nonwovens which were mechanically consolidated in known manner by loop formation using threads or fibers. Nonwovens produced using the familiar web-processing stitch bonding processes are particularly suitable. Also particularly suitable are nonwovens which were consolidated in known manner using high energy (high pressure, for example) water jets.

[0103] Mechanical consolidation is particularly preferred and will now be more particularly described.

[0104] In needling, needles are punched into the web perpendicularly to the web surface and cause web fibers or filaments to become reoriented from the horizontal to the vertical with the formation of stitch channels. The resultant friction consolidates the web.

[0105] In interlooping, a distinction is made between the warp knitting (meshlike interlooping of threads using different constructions, threads in the longitudinal direction of the web), weft knitting (like warp knitting but threads in the transverse direction) and stitch bonding or web stitching. Web stitching with or without thread is preferred.

[0106] Web stitching with or without thread combines sewing (stitching through and joining together of sheets) and formed-loop knitting (synchronous formation of loops from threads or fibers). In web stitching with thread loops are formed from thread and in web stitching without thread loops are formed from fiber. These web-processing stitch bonding processes subdivide into the Maliwatt process (web stitching with thread), the Malifleece process (web stitching without thread), the Voltex process, the Kunit process, the Multiknit process and the KSB process. See FIG. 6-33 on page 305 of Albrecht's monograph.

[0107] In entangling, webs composed of fibers or filaments are consolidated by the action of fluid jets (water, steam, air) having a requisite minimum energy as a result of the impinging jets causing the fibers to become reoriented, entangled, intermingled or interknotted.

[0108] All the aforementioned processes are suitable for producing textile fabrics according to the invention.

[0109] The textile fabrics may include a finish, especially a heat, oil, soil and/or moisture resistant finish. The fabric may be impregnated or coated with the finish.

[0110] Examples of useful finishes for the invention are layers of et al, for example aluminum, applied on one or both sides. Such metal layers, which are customarily applied in a thickness of for example 5 to 200 μm, preferably 10-100 μm, so that the flexibility of the fabric is not adversely affected, protect against fire, heat, especially radiant heat, soot and extinguishant, for example water and foam or powder extinguishants. Under the European standard EN 1486 metallized fabrics are useful for producing protective suits for specialized firefighting. Metallation is generally effected by subjecting the fabric to a high vacuum metal vapor deposition process (see Ullmanns Enzyklopädie der Technischen Chemie, 3rd edition, vol. 15, p. 276 and references cited therein). It is also possible to adhere thin metal foils to the fabric. Such metal foils generally comprise a polymeric support film which has been coated with a thin film of metal. They preferably include a polymeric support based on polyester. The metallized films are suitable according to German armed forces supply specification TL 8415-0203 for application to the inventive fabric on one or preferably both sides thereof, for example by means of an adhesive or by hot calandering. Such foils are used by various manufacturers for the coating of wovens (eg. Gentex Corp., Carbondale Pa., USA; C.F. Ploucquet GmbH & Co, D-89522 Heidenheim; Darmstädter GmbH, D-46485 Wesel).

[0111] It is further possible to produce the wovens of the invention from metallized yarns or fibers. The yarns are preferably coated with aluminum in layer thicknesses within the range of 10-100 μm. The fibers have metal coatings of from 0.01 to 1 μm. Such yarns or fibers are producible for example on the lines of the processes described in DE-B 27 43 768, DE-A 38 10 597 or EP-A 528 192.

[0112] Further examples of useful finishes are water-repellant hydrophobic layers applied to the fabric on one or both sides. Such layers preferably comprise polyurethane materials and/or polytetrafluoroethylene materials. Such coatings are already known from the prior art for improving the weather performance of textiles (see Ullmanns Enzyklopädie der Technischen Chemie, 5th edition, vol. A26, p. 306-312, and Lexikon für Textilveredelung, 1955, p. 211 ff). These coatings can be such that water vapor can diffuse through the layer while they are not significantly penetrated, if at all, by liquid water or similar firefighting products and by combustion products. These coatings are generally adhered or calendered onto the fabric as polymer films.

[0113] Further measures to improve the protective performance of the fabrics comprise finishing the fibers or the fabric with water, oil and/or soil resistant compounds (hydrophobic or oleophobic finish). Such compounds are known as textile assistants to the skilled person (cf. Ullmann's Encyclopedia of Industrial Chemistry 5th edition, vol. A26, p. 306-312). Examples of water-resistant compounds are metal soap silicones, organofluorine compounds, for example salts of perfluorinated carboxylic acids, polyacrylic esters of perfluorinated alcohols (see EP-B-366 338 and references cited therein) or tetrafluoroethylene polymers. The two polymers mentioned last in particular are also used as oleophobic finish.

[0114] The textile fabrics of the invention combine good flame and heat protection, good wear comfort and pleasant hand. These advantageous properties are retained even after numerous cleaning and reconditioning operations. Moreover, the fabrics possess high abrasion resistance and are environmentally friendly.

[0115] The textile fabrics of the invention are useful for manufacturing heat protective clothing and flame protective clothing. This includes workers' protective clothing, welders' protective clothing and protective clothing for working in the steel industry (blast furnace) and chemical industry (chemical reactors).

[0116] The textile fabrics of the invention are similarly useful in vehicles and spaces at risk from fire, for example in seating and lying furniture, mattress covers, wall coverings and wallpapers. Representative examples are upholstery fabrics for fire resistant seat covers, fabrics for curtains, wall coverings, ceiling coverings and wall papers in airplanes, buses, railroad, tram and underground carriages, cable railway cabins, movie houses, theaters, event halls, etc.

[0117] The uses likewise form part of the subject matter of the present invention.

EXAMPLES

[0118] Various fiber blends were used to produce various Maliwatt fabrics in a conventional manner by blending the individual fibers on a conventional fiber processing range from Trützschler (Mönchengladbach) and feeding the blend to a roller card from Spinnbau (Bremen). The resultant wadding was processed in a conventional manner using a machine from Mayer (Obertshausen) into a Maliwatt fabric having a basis weight of 185 g/m2.

[0119] The following stapel fibers were used. The first number indicates the linear density in dtex and the second number indicates the staple length in mm.

[0120] Melamine: The melamine fiber Basofil® 1.8/60 from BASF was used.

[0121] PES I: The commercially available flame resistant polyester fiber Trevira® CS 1.7/38 from Trevira GmbH was used.

[0122] PES II: The commercially available flame resistant polyester fiber Trevira® CS 2.4/50 from Trevira GmbH was used.

[0123] PES III: The commercially available non flame resistant polyester fiber Dacron® 1.7/48 from DuPont was used.

[0124] PA: A commercially available non flame resistant 1.7/60 polyamide fiber from Rhodia was used. It consisted of nylon 66.

[0125] Modacrylic: The commercially available flame resistant modacrylic fiber Kanecar® SYCM 2.2/38 from Kanebo was used.

[0126] The burn tests were carried out to DIN ISO 6941:1995-04 with edge and surface flaming. The flaming time was 15 s.

[0127] The table summarizes the results.

[0128] In the table, - denotes not present, kF denotes no flame present and nb denotes not determined.

1Example1234567V8VComposition [parts by weight]Melamine605040504060— 60PES I20253025202550—PES II20253025202250—PES III————— 3— 40PA———10————Modacrylic————20———PropertiesAfterburn time 0 0 0 0 0 0 0105[s]Afterglow time 0 0 0 0 0 0 0 12[s]FlamekFkFkFkFkFkFkFnbpropagationspeed [mm/s]Burning dripsnononononononoyesMelting dripsnonononononoyesyes

[0129] Nonwovens composed of flame resistant polyester fibers without melamine fibers (comparative example 7V) exhibited melting drips. Nonwovens composed of melamine fibers and non flame resistant polyester fibers (comparative example 8V) exhibited burning and melting drips.

[0130] In contrast, the inventive nonwovens containing melamine and flame resistant polyester fibers exhibited high flame resistance and no burning drips. Examples 4 and 6 show that the admixture of small fractions of non flame resistant fibers—polyamide in example 4 and non flame resistant polyester in example 6—does not affect this advantageous performance profile.

Flameproof textile surface structures

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