Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4209—Inorganic fibres
  • D04H1/4218—Glass fibres
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/44—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling
  • D04H1/46—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres

Definitions

• the present invention concerns a needling aid for producing needle felts of mineral wool in accordance with claim 1, a needle felt in accordance with claim 7, and a method for producing a needle felt in accordance with claim 9.
• Needle felts are particularly suited for thermal insulation in household appliances, for instance in ovens and cookers as well as in industrial muffle-type furnaces.
• a needling aid, or finishing agent For needle-punching mineral wool felts, a needling aid, or finishing agent, must be applied onto the fibers as an additive. Such finishing agents are variously produced on the basis of mineral oils, natural oils or fatty acid derivatives. The finishing agent is required for making the fibers smooth and reducing their mutual friction during the needle-punching process to prevent breakage or rupturing of the fibers during needle-punching as far as possible. The finishing agent must furthermore be capable of binding dusts released during the production process, to thereby permit processing and utilisation of the needle felt in the absence of any additional dust protection measures.
• finishing agents are sprayed onto the fibers in the chute of a fiberising machine for the molten glass material, or directly onto the felt mat. This implies a tradeoff with respect to viscosity inasmuch as sufficient spraying must be ensured on the one hand, whereas a material having a sufficiently high viscosity must be retained following evaporation of the carrier material in order to guarantee the above mentioned advantages for the needle-punching process.
• a thixotropising additive is used with a standard finishing agent on a fatty acid polyglycolester basis.
• Such a thixotropising additive has the advantage of having a high viscosity at rest and thus holding the fiber loops in their anchoring positions achieved by the needle-punching process, whereas the presence of a low dynamic viscosity results in good needle-punching properties and a good lubricating effect. Owing to a high degree of fluidity while the needles are acting on the felt to be needle-punched, it is possible to have to add only small quantities of needling aid, whereby malodors under the effect of heat are correspondingly diminished.
• this object is achieved through the characterising features of claim 1.
• the above object is achieved by the features of claim 7, and in terms of process technology the above object is achieved by the features of claim 9.
• the needling aid of the invention contains an aqueous dispersion of at least one at least partly halogenated polymer, on the one hand there result excellent oil-like finishing agent properties owing to the molecular conditions, and on the other hand those are chemically inert, halogenated polymers which, as a rule, resist thermal decomposition or are otherwise decomposed into non-toxic products.
• Such partly halogenated polymers can be selected from the group consisting of:
• perfluorated perchlorated
• perbrominated are meant to indicate that practically each hydrogen atom within the polymer is replaced by a corresponding halogen atom, wherein one or both terminal groups can be not halogenated or partly halogenated.
• Formaldehyde could be detected neither in the chute nor in the final needle felt which was exposed to a temperature of up to 500°C for approx. 1 hour.
• the perfluorated polyethers in accordance with claim 2 have hitherto turned out to be particularly suitable needling aids as they bring about extremely favorable sliding properties between the fiber loops during needle-punching on the one hand, and as practially all hydrogen atoms within the polyether system are replaced by fluorine atoms on the other hand, such perfluorated polyethers are chemically inert and also thermally resistant.
• the perfluorated polyether in accordance with claim 3 has been found to be a particularly preferred embodiment of a needling aid, which is commercially available e.g. under the designation Fomblin FE 20C.
• Adding another alcohol, in particular a sterically inhibited alcohol, preferably t-butanol, to the needling aid in addition to the halogenated polymer in accordance with claim 4 has the advantage that the dispersion is stabilised by it, with the t-butanol, having a boiling point of approx. 80°C, instantaneously evaporating in the chute without furthermore leaving behind any decomposition products. Addition of such an alcohol stabilises the dispersion or emulsion in water of the polymer used.
• a particularly preferred needling aid is one in accordance with claim 5, wherein the dispersion is present as an aqueous micro-emulsion.
• Such micro-emulsion has the advantage that it presents homogeneous distribution of the utilised halogenated polymer in water even without any costly mixing processes, such that the obtained good results are also reproduceable in subsequent lots.
• the aqueous emulsion Upon application onto the fibers of the mineral wool, in particular glass wool, the aqueous emulsion preferably has a concentration of approx. 0.1 to 0.5% (wt.) of halogenated polymer and approx. 0.05 to 0.45% (wt.) of t-butanol. At these final concentrations during application onto the mineral wool, only small quantities of needling aid are required to obtain the properties desired for needle-punching.
• a needle felt is claimed which can be obtained by using a needling aid according to the invention.
• An important advantage of the needle felt according to the invention resides in the fact that for the first time a formaldehyde-free needle felt is available which will not release formaldehyde even under a high thermal load of up to approx. 500°C in accordance with claim 8.
• the needle felts according to the invention are therefore well suited for thermal insulation in household appliances, in particular ovens and cookers, inasmuch as they produce neither unpleasant smells nor toxic decomposition products upon initial operation at the location of the end user.
• the needling aid according to the invention is suited for needle-punching mineral wool, particularly, however, having the form of glass wool.
• aqueous micro-emulsion of a perfluoropolyether commercially available under the designation "Fomblin FE 20C" was used.
• This emulsion has a polymer content of approx. 20% (wt.) and is stabilised with approx. 18% (wt.) of t-butanol.
• the commercially available solution is diluted with water to a polymer content of approx. 12% (wt.).
• 3 kg of the 12% emulsion are then added into 250 kg of water and mixed by means of a propeller agitator.
• a needle felt produced from glass wool in this manner has a bulk density of approx. 50 kg/m 3 and a thickness of approx. 17 mm.
• the needle felts thus produced were subjected to thermal load at approx. 250°C in a standard kitchen in accordance with DIN 44971 in previously annealed cookers, and possibly produced decomposition products were analysed.
• the needle felts of the present invention therefore have excellent suitability for use in household appliances such as ovens or cookers as a heat insulation material, as it was also found in tests with such apparatus that malodors occurred neither upon initial use nor upon use over a period of several weeks, and that toxic products are not released into the surrounding atmosphere.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Nonwoven Fabrics (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=7799867

Family Applications (1)

Country Status (4)

Cited By (5)

Families Citing this family (1)

Family Cites Families (4)

• 1996
  • 1996-07-15 DE DE19628477A patent/DE19628477C1/de not_active Expired - Lifetime
• 1997
  • 1997-07-14 ES ES97111983T patent/ES2197268T3/es not_active Expired - Lifetime
  • 1997-07-14 SI SI9730567T patent/SI0819788T1/xx unknown
  • 1997-07-14 EP EP97111983A patent/EP0819788B1/fr not_active Expired - Lifetime
  • 1997-07-14 DE DE69721649T patent/DE69721649T2/de not_active Expired - Fee Related

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