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
  • D04H1/54—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 by welding together the fibres, e.g. by partially melting or dissolving
• • 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
  • D04H1/58—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 by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
  • D04H1/60—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 by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives the bonding agent being applied in dry state, e.g. thermo-activatable agents in solid or molten state, and heat being applied subsequently

Definitions

• thermoplastic fibrids as binding fibers in a mixture with staple fibers by the air laying process (aerodynamic fleece formation)
• the nonwoven formed is subjected to a heat treatment which enables the binding fibers to melt or melt onto the staple fibers and thereby the. Solidification of the fleece causes.
• mechanical fleece formation can be carried out at a significantly higher speed.
• a disadvantage of mechanical fleece laying systems is the property of the carding rollers of the cards, that only fibers with a certain minimum length can be combined to form a fleece.
• the tick-shaped scratch coverings of the carding rollers can no longer fully grasp conventional staple fibers with a length of less than approx. 40 mm and use them to form fleece. Fibers shorter than 40 mm would be eliminated in the card and bring the system to a standstill.
• Suitable binders are suitable for binding the relatively long staple fibers of the mechanically laid fleece To be applied to the nonwoven in dissolved, dispersed or emulsified form or as a solid, fine meltable powder with special devices.
• the binders are fixed to the fibers of the nonwoven by drying or melting. As a result, they connect the individual fibers to form a consolidated fleece.
• the fleece is usually passed through heated rolling mills.
• the nonwovens produced in this way are relatively stiff and not very voluminous.
• the object of the present invention was to produce nonwovens mechanically laid from conventional staple fibers using thermoplastic fibers shorter than 40 mm, which serve as binders in heat setting.
• thermoplastic fibrids with a length of e.g. 0.8 to 1.5 mm are excellent as heat-fixable binders for mechanically laid nonwovens.
• the mixtures of such thermoplastic fibrids with conventional staple fibers can be laid in the carding machine over the carding rollers without problems, without these short fibrids separating and falling out, as is the case with other fibers of the same length.
• thermoplastic fibrids as binders
• the production of mechanically laid nonwovens with thermoplastic fibrids as binders is largely carried out in a known manner.
• the staple fiber bales and the fibrid bales are opened up to the base fiber by suitable crushing units and opening units.
• a metered amount of fibrids is fed into the open basic fiber via a premixing chamber, for example a material handling fan. Then the Mixture made of staple fibers and fibrids, which is then placed in the carding machine over the carding rollers to the fleece. After the nonwoven has been formed, the nonwoven web is subjected to a heat treatment at approx. 160 ° C, for example in a suction drum dryer. This heat treatment causes the fibrids to melt onto the staple fiber, so that when the nonwoven is subsequently heat-set by heated rolling mills, the fibrids which melt in the nonwoven dressing remain as binders and are not deposited on the hot roller surfaces of the rolling mill.
• thermoplastic fibrids are mixed into the staple fibers in an amount of 2 to 40% by weight, based on the staple fibers, preferably 10-30% by weight.
• the melting or softening temperature of the fibrids should be at least 10 ° C below the softening temperature of the staple fiber, provided that it is made of thermoplastics.
• native fibers e.g. This requirement no longer applies to cellulose fibers.
• the selection of the fibrids to be used depends on the staple fibers to be processed and can be adapted in the softening range depending on the starting material used for the production of the fibrids.
• thermoplastic fibrids which have been produced, for example, by the flash evaporation method are suitable as binding fibers for mechanically laid nonwovens.
• thermoplastic fibrids used for the process according to the invention for producing mechanically laid nonwovens are preferably those fibrids which are sprayed through a nozzle into a low-pressure zone by flash evaporation of a pressurized, overheated solution of a polyolefin in a low-boiling solvent.
• polystyrene resin Particularly suitable as a polyolefin is polyethylene with a reduced specific viscosity of 0.3 to 30 dl / g, preferably 0.7 to 10 dl / g (determined according to H. Weslau, Kunststoffe 49 (1959) 230) and a density of 0.93 to 0.97 g / cm 3 or polypropylene.
• These polyolefins can contain small amounts of comonomers having 3 to 6 carbon atoms.
• the solvent for the polyolefin must have a sufficiently low boiling point so that sufficient overheating and flash evaporation are possible, but must also have a sufficiently high critical temperature. Therefore, hydrocarbons with 5-7 carbon atoms, preferably cyclic or acyclic saturated hydrocarbons with 5 to 6 carbon atoms, are suitable for the production of the fibrids. Chlorinated hydrocarbons with one or two carbon atoms, preferably methylene chloride, are also very suitable.
• the temperature of the solution can vary within a wide range from 110 to 200 ° C, but the temperature range from 120 to 160 ° C is preferred.
• the solution is under the intrinsic pressure of the solvent mixture, which can be increased with an inert gas and / or with a pump.
• the solution passes through a nozzle, the most important task of which is to maintain a pressure difference between the solution and the flash space.
• the pressure in the expansion space is chosen so that the solvent for the polymer evaporates to more than 90%.
• the pressure is generally from 10 to 1500 torr, but preferably from 50 to 800 torr.
• the polyolefin fibers obtained can be comminuted in commercially available units. They then have a length of 0.8 to 1.5 mm.
• the mixture obtained in this way is processed on a carding machine with a cross layer to form nonwovens of 22.50 and 100 g / m 2 , the total fiber loss (dust content) being less than 3%.
• the single fleece layer in the test is 11 g / m 2 and shows an even distribution of the HP fibers.
• the running speed of the single track is 30 m / min.
• the nonwovens produced in this way are then solidified in a suction drum dryer which works with 40 mm water pressure differential pressures in a hot air stream at 170 ° C. There are no disruptive sticking phenomena between the sieve and the nonwoven during removal.
• the fixing speed in the experiment is 15 m / min.
• the fleece thus consolidated shows a soft feel with high volume.
• the fleece is then calendered between two heated steel rollers at a temperature of 145-150 ° C., without any annoying adhesion to the hot roller surfaces occurring during the removal.
• the nonwovens produced can be welded to themselves or with high or low pressure PE foils using the heat pulse method.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Nonwoven Fabrics (AREA)

Applications Claiming Priority (2)

Publications (1)

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Country Status (4)

Cited By (5)

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Citations (3)

• 1980
  • 1980-12-01 DE DE19803045216 patent/DE3045216A1/de not_active Withdrawn
• 1981
  • 1981-11-25 EP EP81109869A patent/EP0053345A1/fr not_active Withdrawn
  • 1981-11-27 FI FI813817A patent/FI813817A7/fi not_active Application Discontinuation
  • 1981-11-30 JP JP56190957A patent/JPS57121659A/ja active Pending

Patent Citations (3)

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