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US3672943A - Process for the production of an artificial leather and the resultant product - Google Patents

Process for the production of an artificial leather and the resultant product Download PDF

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Publication number
US3672943A
US3672943A US54787A US3672943DA US3672943A US 3672943 A US3672943 A US 3672943A US 54787 A US54787 A US 54787A US 3672943D A US3672943D A US 3672943DA US 3672943 A US3672943 A US 3672943A
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Prior art keywords
web
elastomer
solution
solutions
impregnated
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US54787A
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Gerhard Seibert
Klaus Gerlach
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Glanzstoff AG
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Glanzstoff AG
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    • 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
    • D04H1/64—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 wet state, e.g. chemical agents in dispersions or solutions
    • D04H1/655—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 wet state, e.g. chemical agents in dispersions or solutions characterised by the apparatus for applying bonding agents
    • 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
    • D04H1/425—Cellulose series
    • D04H1/4258—Regenerated cellulose series
    • 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
    • D04H1/4326—Condensation or reaction polymers
    • D04H1/4334—Polyamides
    • 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
    • D04H1/4382—Stretched reticular film fibres; Composite fibres; Mixed fibres; Ultrafine fibres; Fibres for artificial leather
    • 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
    • D04H1/587—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 characterised by the bonding agents used
    • 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
    • D04H1/64—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 wet state, e.g. chemical agents in dispersions or solutions
    • D04H1/645—Impregnation followed by a solidification process
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0086—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
    • D06N3/0086—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique
    • D06N3/0088—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the application technique by directly applying the resin
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24355—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
    • Y10T428/24438—Artificial wood or leather grain surface
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/249921—Web or sheet containing structurally defined element or component
    • Y10T428/249924—Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
    • Y10T428/249933—Fiber embedded in or on the surface of a natural or synthetic rubber matrix

Definitions

  • an imitation leather can be produced from fibrous mats, webs or fleeces which are impregnated with an elastomeric binder to form a flexible, porous sheet which may then be coated with a top layer.
  • the base material or substrate used for this purpose is preferably a fibrous fleece or non-woven web which has been produced by carding or by manufacture on a paper machine and which has been strengthened by mechanical means, for exampleby stitching or by some other treatment such as heating.
  • Impregnation is carried out using a solution or gel of a synthetic elastomeric polymer, polyurethanes being particularly suitable, with which the web is treated so that the solution or gel completely penetrates the fibrous substrate.
  • a solution or gel of a synthetic elastomeric polymer polyurethanes being particularly suitable, with which the web is treated so that the solution or gel completely penetrates the fibrous substrate.
  • the solvent is washed out and the product dried, a substrate or base layer thus being produced in which approximately 20 to 75 parts by weight of the elastomeric binder are uniformly distributed in 80 to 25 parts by weight of fibers.
  • fibrous webs which have been treated with the binder and hardened into the porous substrate are then ground on at least one surface and then provided with a top layer, e.g. a thin surface layer of the same elastomer or another suitable polymer.
  • imitation leathers which can be manufactured by known processes have certain very advantageous properties, such as fine pores, flexibility, abrasion resistance and the like, they still differ considerably from natural leather in their structure.
  • natural leather comprises a very compact upper surface (grain side) and a less dense, more fibrous underside (flesh side), a structure which has not previously been achieved in an imitation leather.
  • the top layer or surface coating of an imitation leather cannot simply be compared with the grain side of natural leather because some of the most important properties such as stretching or elongation, density and compressibility are very different from those of natural leather.
  • Other particularly valuable properties of natural leather such as bending characteristics, the soft handle of its underside and the absence of the so-called orange peel effect are due to the distinctive structure of natural leather.
  • Another object of the invention is to provide a process for the production of an imitation leather employing conventional non-woven webs and elastomeric binders to achieve a microporous, flexible, fiber-reinforced elastomer layer having a variation in its cross-sectional properties quite similar to natural leather.
  • first solutionof elastomer to the lower surface of the moving nonwoven fibrous Web while then applying only one additional solution having a substantially greater concentration of elastomer to the upper surface of the moving web at a point of time which is not substantially prior .to the application of the first solution to the lower surface, i.e. so that impregnation of the upper surface occurs at-approximately the same time or shortly after impregnation of the lower surface.
  • the applications of the elastomer soltuions of different concentrations from below and above the fibrous web must be regulated in place and amount such that a partial overlapping of impregnated layers of separate solutions is provided from top to bottom over the thickness of the web. With these partially overlapping impregnations, the web is then coagulated, washed and dried to provide a microporous layer of increasing density from the bottom to the top thereof.
  • a solution of an elastomer polymer is applied to the underside or lower surface of the fibrous web, preferably by means of a roller applicator, and at the same time or thereafter a plurality of at least two elastomer solutions are successively applied to the upper surface of the moving web.
  • the solution applied to the lower surface of the mat has a lower concentration of the elastomer than any of the solutions applied to the upper surface of the mat and, with several solutions being applied to the upper surface, the elastomer concentration of that solution which is applied at a later stage is higher than that of the solutions previously applied.
  • the distances or intervals between the different positions where the solutions are applied to the upper surface of the web are so chosen that before a new solution is applied, the one previously applied has already penetrated into the surface of the web.
  • the initial material used for the fibrous fleece or web to be impregnated advantageously consists at least partly of synthetic fibres and exhibits a density of 0.08 to 0.30 g./cm. and preferably 0.12 to 0.20 g./cm.
  • These webs or fleeces may be produced in a conventional manner by carding or by a process of deposition from water on a paper-making machine, and then consolidated or strengthened in known manner by stitching and/or by a heat treatment.
  • the concentration of the elastomer solutions should preferably extend over a range from about 8 to 35% by weight, preferably between 12 and 30% by weight.
  • concentrations of the individual solutions, which are applied separately to the non-woven web, are preferably adjusted to the density of the inital web so that the finished product will have as large as possible a difference in density between the upper surface and the lower or bottom surface.
  • the initial web itself may be of substantially uniform density.
  • a difference in concentration between the different elastomer solutions has a more pronounced effect in producing a variations in the density over the thickness or width of the finished product than in webs of higher uniform density.
  • comparatively more highly concentrated solutions should be used for initial fibrous webs of lower density.
  • impregnating materials which are especially suitable for this process are solutions of polyurethanes is dimethylformamide or in similar organic solvents known for this purpose.
  • the handle and suppleness of the imitation leather can be improved by adding 5 to 30% by weight of paraffin oil or silicone oil (based on the weight of elastomer) to the elastomer solution applied to the bottom surface of the web.
  • the elastomer solution or solutions applied to the upper surface may contain up to by weight, based on the total polymer content of a vinyl chloride polymer such as polyvinyl chloride or vinyl chloride copolymers. This improves the capacity of the material to be fixed by heat, which is especially important if the imitation leather is to undergo subsequent processing commonly employed in the shoe industry.
  • the process of the invention is applicable to any solvent-soluble synthetic elastomeric binder capable of being coagulated into a vapor-permeable and preferably microporous film or substrate.
  • elastomeric polymer binders are referred to more simply as elastomers.
  • Suitable elastomers and their solvents as well as non-solvents employed to gel or coagulate the dissolved polymer are disclosed in great detail in the prior art, for example as set forth in U.S. Pats. No.
  • the polyurethanes exhibit especially desirable leather-like qualities whether used along or in combination with other wellknown elastomeric polymers or even small amounts of non-leastornen'c polymers. For this reason, the use of a polyurethane elastomer is especially preferred without excluding minor proportions of other'suitable elastomers. Moreover, it is desirable to select an elastomer which can be dissolved over the broadest possible range of concentration consistent with subsequent coagulation and formation of a vapor-permeable structure, and the polyurethane elastomers are especially suitable for this purpose. Of course, other known additives may also be included in the initially prepared elastomer solutions, usually in very minor amounts although the solution forming the top layer in the process of the invention may contain relatively larger amounts of other elastomers and/or compatible additives.
  • FIG. 1 is a schematic flow sheet or side elevational view of suitable apparatus for continuously carrying out the process of the invention.
  • FIG. 2 is a diagrammatic longitudinal cross-sectional view on an enlarged scale of the non-woven fibrous web undergoing impregnation with different elastomer solutions.
  • a substantially dry non-woven fibrous web is continuously supplied by means of a pair of feed rollers 2 and passed over a roller applicator 3 which rotates in a vat 4 containing a first polyurethane solution of relatively low concentration.
  • a stripping knife 5 is directed toward the surface of the roller just before its point of contact with the fibrous web.
  • the distance of this knife 5 from the surface of the roller may be, for example, about or A the thickness of the fibrous web, the thickness of layer of polyurethane remaining on the surface of the roller and transferred to the fibrous web being substantially equal to a predetermined set interval between the knife and the surface of the roller.
  • the polyurethane solution penetrates the fibrous web from the bottom side and is absorbed relatively quickly by the web. 7
  • a doctor knife 6 is arranged above the roller 3 to sup ply an elastomer solution onto the top surface of the web, this second solution having a substantially higher concentration of elastomer than the first solution A.
  • the width of the gap between the doctor knife 6 and the surface of the web 1 is adjusted to about A or of the thickness of the fibrous web. Since the rate at which the elastomer solution penetrates the web depends partly on the viscosity of the solution, i.e.
  • the quantity of binder used for impregnation is not determined entirely by the width of the gap between the doctor knife and the surface of the web, it is advisable to determine the most suitable width of the gap by a few trial adjustments.
  • the fibrous web is carried along freely until the applied coating or layer applied has penetrated into the fleece. This point of penetration is easily recognized since the surface of the web then appears to be fibrous and almost dry.
  • Another elastomer solution C of still higher concentration than either of the solutions A and B is then applied 1 onto the top surface of the web 1 by means of a doctor knife 7, in this case arranged above a roller 8.
  • the width of the gap between the doctor knife 7 and the surface of the web 1 is adjusted'according to the thickness of the layer of elastomeric impregnating agent which is to be applied to the fibrous web, as explained above.
  • thecontinuously moving web passes between a pair of nip rollers 9 which exert a very slight pressure on the fleece in order to relatively even out the impregnation but without squeezing off any elastomer solution or changing the relative positions of the separately applied layers.
  • a fourth elastomer solution D of highest concentration is applied by means of a doctor knife 11 arranged over a roller 10.
  • the web which is now completely impregnated with elastomer solutions is introduced into a vat 12 containing water as a non-solvent precipitating bath in which coagulation of the elastomeric binder takes place.
  • Subsequent treatment can-also be carried out continuously in known manner inconventional apparatus (not shown) arranged after the vat, the solvent first being washed out and the resulting porous product then dried.
  • the impregnated fibrous web after being dried can be wound and stored.
  • the material may then be ground to smooth the top surface and provided with a top layer of an elastomer such as the preferred polyurethane.
  • the material may be directly subjectedto the usualleather finishing treatments immediately after drying, especially if the last applied layer of polyurethane has not been permitted to completely penetrate into the top surface before coagulation.
  • the process illustrated in FIG. 1 may also be modified in that all the solutions may be applied to the upper surface of the web or, instead of applying solution B in approximately the same location as solution A, it may be applied at some distance displaced from the location of application of solution A in the direction of continuous movement of the fibrous web.
  • another combined assembly of doctorknife and guide roller is arranged after the guide roller.3.
  • the individual elastomer solutions are most conveniently applied by means of a knife or doctor blade except for those instances in which the first solution A is applied to the bottom surface where a roller applicator is preferred.
  • the individual impregnated layers can each be about onethird of the thickness of the initial dry web. This procedure is of course subject to a relatively broad variation, but it will generally be found preferable to employ variations in such a manner that those solutions with the lowest concentration of elastomer are applied in wider or thicker layers while the more concentrated solutions are correspondingly reduced in thickness.
  • the primary object of a carefully regulated application of individual elastomer solutions of different concentra tion is to achieve an impregnated web with a moreor less gradually increasing content of the elastomer from the bottom surface to the top surface.
  • the nip rollers 9 located between the last fully impregnated solution C and the top coating D and/or between preceding impregnated solutions B and C have the effect of achieving not only a more uniform evening out of individual layers of solution but also a bringing together of the applied layers internally of the web and ensuring a partial overlapping of the layers in terms of a variation in the concentration content of elastomer over the thickness of the web.
  • the liquid solvent in each layer is somewhat more fluid or exchangeable between adjacent layers, and by using a very slight pressure on the completely or partially impregnated web, there occurs a blending of the fluid solutions at their interfaces and a corresponding transfer of one layer of more concentrated elastomer into the next adjacent layer of less concentrated elastomer. It will be understood, of course, that such evening out or blending of the solution layers must not cause any substantial removal of solvent, and a complete blending of one layer with another must be avoided. Therefore, depending upon the viscosity of the layers, it is often preferred to avoid using the nip rollers 9 or else employ them only under an extremely slight pressure since there is a natural tendency for the layers to blend by themselves.
  • FIG. 2 The overlapping or blending processes which occur when impregnation is carried out in several stages are illustrated diagrammatically in FIG. 2.
  • the initially dry fibrous web 13 is shown on a scale which is greatly enlarged compared to the linear indication of the web 1 shown in FIG. 1.
  • This web 13 corresponds to a longitudinal cross-section of a short length of the moving web, the arrow indicating the continuous direction of open space bounded by the top surface 13a and the bottom surface 13b.
  • the elastomer solution A is applied to the bottom side. 1311 of the web by means of the roller 14.
  • This first layer A of the impregnating agent on roller 14 is stripped oif by means of a knife (not shown) to a thickness equal to about /3 of the thickness of the fibrous web 13. Owing to therelatively low viscosity of solution A, it penetrates fairly rapidly into the fleece which is being moved forward, andit becomes distributed over the shaded area or thickness of the web roughly indicated by the reference numeral 15.
  • the solution B which is more highly concentrated, is applied at a position transverse to the moving web and approximately directlyabove the axis of the roller 14'by means of a doctor blade 18.
  • thissolution B penetrates the fleece slightly 'more slowly and becomes distributed as the shaded layer 16 in the fibrous web.
  • SolutionC the distribution of which is indicated by the referencenumeral l 7 ,'"i s applied with doctor blade 19 to the top surface 13a of the web at the transverse location 17 when no.
  • more-ofthe impregnating agent or solution B can beseenonthe surface of the web, i.e. when the surface appears almostdry. Owing to the still higher viscosity of this solution C and the solutions already present in the web solution C, penetrates evenmore slowly. Theboundaries of the layers of impregnating agent. 15, 16 and 17 are not sharpQbut-blurred or blended together. Viewed as a whole, it is precisely due to these gradual transitions from one layer of an elastomer solution to the next in the fibrous web that the density of the elastomer material increases more or less continuously from the bottom surface 13b to the upper surface 13a in the finished imitation or synthetic leather product.
  • top coating or layer of elastomer D as shown in FIG. 1 is optional, for example to ensure a final complete impregnation of the web or an excess surface coated layer to completely hide the fibrous material of the web, e.g. to prevent any loose ends or loops from projecting from the top surface.
  • a special elastomer composition may be used.
  • elastomer concentration of D may be approximately the same as that ofsolution C, simply to provide a finish-' ing touch or final filling of the web to provide avery uniform top layer just before coagulation.
  • the final products produced in accordance with. the.in-. vention exhibit a finely porous, dense grain side 7 (upper surface) and a softer, fibrous flesh side (bottom,surface). This structure can be clearly observed when the synthetic leather is split.
  • the split layers moreover distinctly exhibit a firmness which'decreases and a pore size which increases from the upper surface to the bottomsurface of the synthetic leather.
  • a non-woven fleece or web is prepared from an aqueous dispersion of nylon fibers and regeneratedcellulose fibers (in a weight ratio of polyamidezviscose fibers of :20) by 'deposition'ona paper-making machine, and the waterlaid web is consolidated, i-.e., rendered more strongly coherent, by a brief heat treatment.
  • the dry fibrous web has a weight of 310 g./m a density of 0.13 'gl/cmfiand a thickness of 2.4 mm.
  • the polyurethane used inall solutions is the reaction product of polybutylene adipate'having an average 'molecular weight of approximately 1000, diphenylmethanetfl' diisocyanate and butanediolin a molar ratio *or1;'3.1 :211.
  • the silicone oil is a phenylmethyl"polysiloxane with a with solution A.
  • a knife is arranged just beforethepoint ofcontact 'between'the roller and the bottomsuiface or; the web-at a short distance from the roller surface in order to strip the solution-A to a layer thickness of'0.'5
  • the web or fieeceruns freely for alength 0150.6 meter (60 cm.) and is then passed between a pair of hip rollers providing a slight pressure.
  • the solution-B has completely 'pene- I trated into the fibrous web, i.e.'so .that the surface of the I distance of 0.5'meter (50 cm.) beyond the pair of'nip rollers, the web is conveyed over a guide roller arranged to cooperate with a second doctor blade, which is arranged at a gap distance of 0.7 mm. from the top surface of the web and applies solution C at the rate of 0.8 kg. of solution per square meter of fibrous web.
  • the web enters a bath of water maintained at a temperature of 40 C. in which the elastomers are coagulated and the solvent is washed out to form a porous elastomeric structure.
  • the web is then dried carefully under conventional conditions to maintain the desired porous structure.
  • the finished synthetic leather weighs 715 g./m.
  • the finished product is split into three layers of equal thickness, each layer amounting to 0.64 mm.
  • the densities of these layers taken in order from the bottom surface to the upper surface, are found to be 0.29, 0.34 and 0.48 g./cm. respectively.
  • EXAMPLE 2 The process described in Example 1 is repeated, using a dry fibrous web of the aforesaid composition which has a thickness of 2.53 mm. and a density of 0.13 g./cm.
  • the polymer solutions used in succession have the following compositions:
  • the polyurethane used in this instance was prepared by reacting polybutylene adipate (molecular weight of approximately 1000), diphenyhnethane-4,4'-diisocyanate and butanediol in proportions of 1:2: 1.
  • the impregnated web After application of the solutions in the same manner as described in Example 1, the impregnated web is passed through the water bath without any appreciable application of pressure during coagulation.
  • the resulting imitation leather after being dried has a weight of 775 g./m. and a thickness of 1.29 mm.
  • the densities of the three split layers, each 0.43 mm. in thickness, are 0.52, 0.60 and 0.68 g. cm. respectively, measured in the order of the layers from bottom to top.
  • Solution A Percent by wt. Water 6.0 Dimethylformamide 78.0 Solution B:
  • the polyurethane in this instance was prepared by reacting polybutylene adipate (molecular weight of approximately 1000), diphenylmethane-4,4-diisocyanate and butanediol in the ratio of 1:2.5: 1.5.
  • the coagulation treatment in the aqueous bath is carried out without application of pressure.
  • the resulting imitation leather has a.weight of 778 g./m. and a thickness of 1.75 mm.
  • the three split layers, each of 0.58 mm. in thickness, have densities of 0.33, 0.46 and 0.56 g./cm. respectively.
  • EXAMPLE 4 A fibrous web having a density of 0.145 g./cm. and a thickness of 2.81 mm. is again impregnated as in Example 1 with three distinct solutions of the following compositions:
  • the polyurethane was prepared by reacting polybutylene adipate (molecular weight of approximately 1000), diphenylmethane-4,4-diisocyanate and butanediol in the ratio of 1:2.25:1.25.
  • the finished imitation leather product After treating the impregnated fibrous web for coagulation of the elastomers without application of pressure followed by washing and drying, the finished imitation leather product had a weght of 885 g./m. and a thickness of 2.40 mm.
  • EXAMPLE 5 A fibrous web of 1.85 mm. in thickness and having a density of 0.22 g./cm. is used as the initial material and is impregnated successively as in Example 1 with solutions having the same composition as indicated in Example 4.
  • the imitation leather which is slightly compacted during coagulation, exhibits a weight of 687 g./m. and a thickness of 1.31 mm.
  • the split layers which are 0.41 mm. in thickness, have a density of 0.47, 0.52 and 0.67 g./cm. respectively.
  • EXAMPLE 6 Starting with the same non-woven fibrous web as in Example 5, impregnation is carried out in three stages 1 1 under the same conditions as indicated in Example 1. The solutions applied in succession have the composition set forth in Example 2. Coagulation of the polymer is then carried out without application of pressure and conventionally washed and dried.
  • the imitation leather product has a weight of 705 g./m. and a thickness of 1.31 mm.
  • the split layers have a thickness of 0.4 mm. each and densities of 0.48, 0.52 and 0.62 g./cm. respectively.
  • the smoothed or developed grain side of the product according to the invention can be merely dyed or finished in the same manner as normally observed for the conventional treatment of both natural and synthetic leathers.
  • a process as claimed in claim 2 wherein the solvent solution applied to the lower surface of the web contains. about 5 to 30% by weight, with reference. to the weight of elastomer, of parafiin oil or silicone oil.
  • a process as claimed in claim 12 wherein the initial non-woven fibrous to be impregnated has a density, of about 0.12 to 0.20 gram/emi v 15.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Dispersion Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Synthetic Leather, Interior Materials Or Flexible Sheet Materials (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
US54787A 1969-07-16 1970-07-14 Process for the production of an artificial leather and the resultant product Expired - Lifetime US3672943A (en)

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JP (1) JPS4948482B1 (da)
AT (1) AT309088B (da)
AU (1) AU449513B2 (da)
BE (1) BE750989A (da)
CA (1) CA922181A (da)
CH (1) CH533201A (da)
CS (1) CS151560B2 (da)
DK (1) DK136222C (da)
ES (1) ES380405A1 (da)
FI (1) FI53326C (da)
FR (1) FR2051784B1 (da)
GB (1) GB1307294A (da)
IE (1) IE34115B1 (da)
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LU (1) LU61332A1 (da)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928627A (en) * 1971-07-22 1975-12-23 Walter E Heller Factors Inc Decorative wall covering
US3941902A (en) * 1973-03-02 1976-03-02 Svenska Cellulosa Aktiebolaget Method of making surface-treated paper
US4135011A (en) * 1974-10-03 1979-01-16 Teijin Cordley Ltd. Process for producing microporous sheet materials

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4827442B1 (da) * 1965-05-10 1973-08-22

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928627A (en) * 1971-07-22 1975-12-23 Walter E Heller Factors Inc Decorative wall covering
US3941902A (en) * 1973-03-02 1976-03-02 Svenska Cellulosa Aktiebolaget Method of making surface-treated paper
US4135011A (en) * 1974-10-03 1979-01-16 Teijin Cordley Ltd. Process for producing microporous sheet materials

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NO129304B (da) 1974-03-25
GB1307294A (en) 1973-02-14
NL7008046A (da) 1971-01-19
AU1479770A (en) 1971-11-18
CH533201A (de) 1973-01-31
CA922181A (en) 1973-03-06
BE750989A (fr) 1970-11-03
CS151560B2 (da) 1973-10-19
DK136222B (da) 1977-09-05
FR2051784A1 (da) 1971-04-09
ES380405A1 (es) 1972-09-01
DE1936073B2 (de) 1976-11-04
IL34476A (en) 1974-06-30
DE1936073A1 (de) 1971-02-25
DK136222C (da) 1978-02-06
AT309088B (de) 1973-08-10
IE34115L (en) 1971-01-16
IL34476A0 (en) 1970-07-19
FR2051784B1 (da) 1974-05-03
AU449513B2 (en) 1974-05-31
LU61332A1 (da) 1970-09-14
SU460633A3 (ru) 1975-02-15
FI53326C (fi) 1978-04-10
FI53326B (da) 1977-12-30
IE34115B1 (en) 1975-02-05
JPS4948482B1 (da) 1974-12-21

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