Abstract: A consolidated web may be produced by impregnating it with a compound of latex of a polymer comprising from about 10 to about 45 weight percent of a C.sub.3-6 alkenyl nitrile; from about 36 to 85 weight percent of a C.sub.4-6 conjugated diolefin; from about 5 to 20 weight percent of a monomer mixture comprising from 100 to about 60 percent of a C.sub.8-12 vinyl aromatic monomer which may be unsubstituted or substituted by a C.sub.1-4 alkenyl radical or a chlorine or bromine atom; from 0 to 40 weight percent of a C.sub.1-2 alkyl ester of acrylic or methacrylic acid; from about 0.5 to 10 weight percent of at least one, C.sub.3-6 ethylenically unsaturated carboxylic acid; and from about 0.1 to 5 weight percent of an N-C.sub.1-4 alkylol derivative of an amide of a C.sub.3-6 ethylenically unsaturated carboxylic acid; from 40-100 parts by weight of a filler, an effective amount of a gelling agent and optionally a cure paste.

Abstract: A composite sheet comprising a fiber base and a binder, wherein said binder is broken into small fragments which adhere to the fibers, but at least some not to each other.Said composite sheet is produced by a method comprising the step of (a) applying a binder to a fiber base and (b) directing a fluid jet stream to the fiber base during or after coagulation of the binder applied thereto.The composite sheet of this invention is very soft and has considerable strength, because the fluid jet breaks weak portions of the binder only to divide the binder into small fragments, without breaking the tougher portions of the binder which mainly contribute to the strength of the leather.

Abstract: A substrate having an appearance similar to that of nubuk-leather or pile-leather, respectively, or of a textile pile consists of a textile carrier body being at least partially impregnated with a, preferably cross-linked, polymeric synthetic plastics material consisting of a foam which has open cells formed by introducing air and optionally has closed cells formed of hollow microspheres. The textile carrier body consists of a fleece or of a knitting, preferably of a crimped fleece of synthetic fibres, which is needled together with a knitting or with a fleece, strengthened by thermal embossing, in such a manner that the fibres extend through the knitting. The knitting may consist of a roughened stockinet, i.e. a stockinet having opened loops. The carrier body is ground at least at its one impregnated surface and is thus rough and can be provided with a coating.

Abstract: A sheet of artificial leather made of polyvinyl chloride the back of which is coated with a dry adhesive capable of being activated by heat. The dry adhesive consisting of the product of the reaction between a substantially linear hydroxypolyurethane derived from a polyester and a partially blocked aromatic triisocyanate in a proportion such that the dry adhesive has an isocyanate value of at least 100. The adhesive may additionally contain polychloroprene. The sheet of artificial leather can be used for thermocovering of rigid articles which are not previously coated with glue, especially dash boards and door panels for motor vehicles made of ABS resin.

Abstract: The present invention relates to a process for the preparation of a synthetic leather which comprises converting a leather perfume into the corresponding cyclodextrin clathrate compound, powdering the clathrate compound by drying, mixing the powder with a synthetic resin material and molding the mixture to form a synthetic leather material, thus imparting a natural leather-like material odor to the synthetic leather.

Abstract: Process particularly suitable for artificial leather of the type whereby a porous polyurethane resin matrix containing polyester and/or polyethylene fibers is covered with a compact, pressed polyurethane resin film, and consists of treating the artificial leather in rotary tanning drums, firstly, with a relatively concentrated solution of water and PIROFLAM (registered trade mark) or other similar commercial fireproofing/retarding substance of the type commonly employed for extinguishing forest fires, and, secondly, with a solution of water and softener, e.g. TRIANOL SP (registered trade mark) to which is added an appropriate amount of the same fireproofing/retarding substance used previously on the artificial leather.

Abstract: An ink ribbon comprises an ink supporting member, an intermediate layer mounted on the ink supporting member, and ink mounted on the intermediate layer. The ink has supercooling property and is susceptible to softening or melting by heat, and the intermediate layer is adapted to reduce adhesion of the ink to the intermediate layer above a temperature at which the ink is softened or melted. A thermal-transfer recording apparatus best adapted for use of the ink ribbon described above, comprises a thermal head including a plurality of heating elements and being in sliding contact with the ink ribbon, the heating elements being adapted to be heated for predetermined patterns so that the ink of the ink ribbon in sliding contact with the thermal head is heated to be softened or melted into the predetermined patterns, and is transferred to the recording paper overlapping the ink ribbon.

Abstract: A method of working leather, in which a deposit of material adhering to the leather is made on the surface of the leather to enable a leather footwear upper treated in this way to adhere to a sole without being carded or sanded, either by direct injection of sole-constituting material, or else by bonding on or by gluing on a prefabricated sole, and/or to enable the leather to be worked by a high frequency current.

Abstract: A nonwoven sheet is provided having lengthwise and transverse directions, said sheet being composed mainly of fine fibers which are individually distributed substantially throughout the sheet and mainly oriented in the lengthwise direction. The sheet also includes yarn-like fiber bundles of fine fibers which are also oriented in the lengthwise direction of the sheet. The yarn-like fiber bundles outnumber the fine fibers on one surface of the sheet material and the fine fibers outnumber the yarn-like fiber bundles on the other surface of the sheet material.

Abstract: A composite sheet material having a soft, suede-like surface appearance and feel, high liquid absorption and retention, and improved resilience and abrasion resistence suitable for use as a wiping cloth comprising a reinforcing textile fabric substrate having opposed raised fiber surfaces, a water-absorbent, porous, polymeric foam layer composition comprising a acrylonitrile-butadiene polymer and a polyacrylate polymer secured to each of the raised fiber surfaces of the fabric with the fibers substantially embedded therein, and a plurality of flocked fibers embedded in and extending from the outer surface of each foam layer, the fibers having a length of from about 0.75 to 1.25 ml. and providing improved liquid absorption of the fabric and reduced surface tack. Preferably the textile fabric substrate is a woven fabric containing hydrophilic cellulosic yarns and fibers, and the flocked fibers embedded in the outer surface of the foam layers are hydrophilic cellulosic fibers, such as cotton.

Abstract: Artificial leather having a novel structure comprises a non-woven cloth mat or fluffy cloth as the base, while the structure is filled with foamed PVC. The product thus formed is of excellent physical property, resilience and hand feeling.

Abstract: According to the invention, grip tapes based on plastic-coated supporting materials are described which have a supporting material comprising nonwoven, woven or knitted fabric having an extensibility before processing of at least 10% in the crosswise and/or lengthwise and/or diagonal direction, and an impregnation based on polyurethanes which is applied by means of wet coagulation. The grip tapes are obtained by soaking a supporting material of nonwoven, woven or knitted fabric and having an extensibility of at least 10% in the crosswise and/or lengthwise and/or diagonal direction in a solution of polyurethane-based impregnating agent, dissolved in a water-soluble solvent, passing the impregnated material through at least one coagulation bath comprising a mixture of the solvent with water, pressing the liquid out of the coagulate-coated supporting material, then rinsing the material with water and pressing it again and drying it, then cutting it as needed into strips.

Abstract: An artificial grain leather sheet free of rubber-like elasticity and characterized by excellent softness and strength composed of ultrafine super-entangled synthetic fibers having a denier of less than about 0.5 and a resin. The sheet has a body portion and a grain surface portion wherein the ultrafine fibers are supertangled at a multiplicity of entangling points, with the average distance between entangling points being less than about 200 microns and the fiber density coefficient near the surface being greater than about 30.

Abstract: Improved ultrafine sheath-core composite fibers and composite sheets composed of these fibers are disclosed. The composite fibers have a fineness of 0.0001 to 0.5 denier and comprises 10 to 70% of the core having a very high intrinsic viscosity within a specific range and being located at the center of the sheath and 90 to 30% of the sheath composed of a polyester copolymerized 1.5 to 8 mole %, based on the total acid component, of 5-sodium (or lithium or potassium) sulfoisophthalate and having a thickness of 0.04 to 2 microns. The composite fibers have a high strength and are dyeable with a cationic dye. When the composite fibers are combined with an elastic material such as polyurethane, suede-like artificial leathers having excellent softness, touch, feel and color can be obtained.

Abstract: A method of preparing an impregnated leather composite is provided. A low density leather sheet is impregnated with an aqueous ionic dispersion of a polyurethane polymer. The polyurethane polymer which is impregnated in the leather sheet is ionically coagulated from the dispersion. The impregnate is dried to form an impregnated leather composition.

Abstract: The present invention concerns an artificial grain leather comprising a fibrous substrate and a coating layer, said substrate comprising a body portion of entangled ultrafine fibers and a surface portion of non-entangled ultrafine fibers, said coating layer being composed mainly of an elastic high polymer, and said coating layer, said portion of non-entangled ultrafine fibers and said portion of entangled ultrafine fibers being continuously connected in this order.

Abstract: An artificial split suede leather, especially for sport or casual style shoes, is a split, needled, nonwoven material of unshrunk fibers containing at least 20% polyamide fibers by weight of the fibers having a trilobate, Y-shaped cross section. In a process of making it, only needling is used for consolidating the fibers. A spherical filler may also be used.

Abstract: Laminated artificial leather having a structure characterized in that, in-between a PVC foamed abraded bottom layer and a top layer of wet PU abraded or a special formulated PVC non-foamed sheet or a ground sheet of very low foaming rate, lamination of single or multilayer foamed and non-foamed PVC are inserted as intermediates. After the addition of leather like smell flavor and punched with micro-perforation, the final product gives both surfaces a hand feeling of Nu-Buck leather with excellent stability yet the cost is low and easy to work with.

Abstract: A process is dislosed for producing a support suitable for use in the formation of polyurethane films, the support comprising a base and a releasing layer on the base comprising a polymeric mixture of 95 to 65 parts by weight of polypropylene and 5 to 35 parts by weight of polyethylene, which process comprises extrusion coating the base with said mixture through a T-die to form the releasing layer on the base, the temperature of the mixture as extruded through the T-die being controlled below 300.degree. C.

Abstract: The invention relates to a waterproof and air-tight, moisture-conducting textile material (1) which has a coating (3) of coagulated polyurethane containing preferably a great number of micropores, and which has a water vapor permeability of more than 5000 g/m.sup.2 in 24 hours.

Abstract: A material for clothes is disclosed which is formed of a base cloth and a porous film having a number of very fine pores and coated on at least one surface of the base cloth. In this case, the pores are made to have a diameter about 0.1 to 5 .mu.m and the material has the percentage of dust permeation less than 50% for the dust with size larger than 0.3 .mu.m and moisture permeability more than 2500 g/m.sup.2 /24 hrs.

Abstract: This invention relates to compositions of aqueous polyurethane dispersions containing polyurethanes having lateral OH-groups, optionally in admixture with PU-dispersions without any lateral OH-groups, which contain a combination of formaldehyde resins and blocked polyisocyanates as crosslinking agent and, optionally handle-improving agents, silicones and standard additives.The present invention also relates to the use of these compositions for the production of light coatings by the heat-activated, one-coat reverse coating process, in which the PU-composition is applied to a temporary support and dried, after which the (textile) substrate is laminated onto the dry polyurethane film at elevated temperature and pressure and the polyurethane laminate formed is subsequently crosslinked at a relatively high temperature.Mixed crosslinking with formaldehyde resins plus blocked polyisocyanates makes it possible to obtain coatings characterized by outstanding substrate adhesion and wet strength values.

Abstract: This invention relates to a release sheet which comprises a backing sheet, a release resin layer and a pattern layer, the pattern layer being positioned directly or indirectly on the reverse side of the release resin layer in relation to a peeling surface thereof. The release sheet is useful especially as a release sheet used in making synthetic leather.

Abstract: The present invention relates to an artificial grain leather having different color spot groups comprised of ultra fine fibers, in which at least one side of the fibrous substrate has two types of colors differing in hue and/or lightness value and being covered with transparent resin layers.The present invention produces a three-dimensional surface effect and a grain pattern effect, and is recognized as consisting of a mixture of ultra fine fibers each being quite different in color from the next, though providing the appearance of a single color from a distance, and producing a subdued and rich appearance as a result of the integration of colors by the color of a coating layer.

Abstract: Melange-colored sheet and method. The sheet has an inner portion having ultrafine fiber bundles and/or multi-core fibers. The surface of the sheet is composed of super-entangled ultrafine fibers and/or fine bundles of ultrafine fibers of different colors, branched from the fibers of the inner portion, so that the surface presents a melange-colored effect of at least two colors.

Abstract: A leather-like sheet material having low slip characteristics comprising:a sheet material having a fibrous substrate and a surface layer consisting of a polymer mainly composed of polyurethane elastomer, andan acryl-modified polyurethane resin spread on the said surface,whereby the sheet material has a remarkably high friction coefficient, and is adapted to balls, baseball gloves, bags, cases and the like which are required to prevent slipperiness.

Abstract: An entangled fibrous mat comprising an elastic polymer fiber A and a nonelastic polymer fiber B, said fiber A having voids therein and being in a taut condition within the mat; while said fiber B is in a slack condition and is highly elastic and flexible, rich in fullness, and firm-bodied, thus being very suitable for use as a substrate for artificial leather.

Abstract: The synthetic leather has high tensile strength and elongation which are well balanced in both transverse and longitudinal directions due to the use of a fabric knitted in a plurality of strokes as the base fabric bonded to a synthetic resin by means of an adhesive. Especially because elongation is well balanced in both directions, the synthetic leather can be used suitably as a leather for any object which is subjected to repeated heavy loads.

Abstract: A process for preparing a porous sheet material, which comprises impregnating and/or coating on a substrate a water-in-oil type polyurethane emulsion (d) comprising a hydrophobic polyurethane (a), a hydrophilic polyurethane (b), and organic solvent (c) and water, and drying it, characterized in that said hydrophobic polyurethane (a) is a hydrophobic polyurethane dispersion (e) obtained by reacting a hydrophobic polyol, an organic diisocyanate and a chain extender is an organic solvent (c) which has a limited compatibility with water and in which the polyurethane thereby formed is substantially insoluble; said hydrophilic polyurethane (b) is a polyurethane containing about 20 to about 40% by weight, based on the total polymer, of polyoxyethylene groups; and the weight ratio of (a):(b) is about 90-99: about 10-1.

Abstract: The present invention is directed to a process for the preparation of finely dispersed, easily spreadable, aqueous polyurethane reactive coating compositions suitable for coating textile sheet products, artificial leather or leather by the direct or transfer coating process by(i) forming an aqueous dispersion having a solids content of about 20-69 wt. % of blocked isocyanate prepolymers in the presence of from about 0.05-5% by weight of emulsifiers,(ii) adding during or after formation of the dispersion about 0.1 to 2.5% by weight of water soluble thickeners based on long chain polyethylene oxides, salts of poly(meth)acrylic acids or salts of carboxy methyl cellulose, up to 100% by weight of aqueous polymer solutions and/or polymer dispersions and optionally levelling agents, pigments, fillers or stabilizers and(iii) forming a coating composition having a viscosity of from about 3000 to 22,000 mPa.s/25.degree. C.

Abstract: Laminated artificial leather is disclosed having in between a face layer selected from an ordinary PVC or PU sheet and a bottom layer of a foamed abraded PVC, at least one intermediate layer selected from a fabric cloth or foamed PVC, and ideally a second intermediate layer of ordinary PVC sheet. The laminate is formed by adhesion, foaming and embossing, the final product having the feel of genuine leather. In practicing the invention, fabric cloth is not used either as the bottom of the laminate or as a backing for the bottom layer.

Abstract: A reconstituted leather product and a method of manufacturing this reconstituted leather product is disclosed in which leather (preferably scrap leather) is ground or shredded into a fibrous state. The fibrous leather is mixed with a binder, such as natural rubber dissolved in an evaporatable solvent (e.g., naphtha), so as to form a paste-like mix. The mix is then extruded (or otherwise formed) into sheets or webs and is cured so as to drive off excess solvent. A reinforcing mesh web may be adhered to the back face of the sheet or may be sandwiched between layers of the fibrous leather and binder. The cured reconstituted leather may be finished to have any desired surface finish or color in a manner similar to real leather. The resulting reconstituted leather closely resembles real leather in feel, color, finish, odor, strength, flexibility, and appearance, but is of much lower cost.

Abstract: A stable aqueous polymeric composition is comprised of an aqueous anionic polyurethane dispersion and a compatible polymeric dispersion or emulsion. The compatible dispersions or emulsions may have a substantially neutral pH or be anionic or cationic. The polymeric compositions are useful in impregnating porous substrates to form composite sheet materials which can be further processed to form simulated leather and the like.

Abstract: This invention relates to a method of producing a moisture-permeable artificial leather comprising transferring a water-soluble inorganic salt-containing polyurethane layer onto a base fabric and washing the polyurethane layer with water to extract out said water-soluble inorganic salt. A feature of the invention is that the inorganic salt used has a particle diameter range such that at least 90% thereof is not larger than 30 microns.

Abstract: An entangled non-woven fabric having a fiber structure which comprises a portion (A) in which ultrafine fiber bundles consisting of ultrafine fibers of a size of not greater than about 0.5 denier are entangled with one another and a portion (B) in which ultrafine fibers to fine bundles of ultrafine fibers branch from the ultrafine fiber bundles and are entangled with one another, and in which portions (A) and (B) are nonuniformly distributed in the direction of fabric thickness. The product of this invention has high flexibility as well as good shape retention.The invention also relates to a grained sheet having on at least one of its surfaces a grain formed by a fiber structure composed of ultrafine fibers to fine bundles of ultrafine fibers and having a distance between the fiber entangling points of not greater than about 200 microns, and a resin in the gap portions of the fiber structure.

Abstract: Articles having leather-like appearance are obtained from compositions comprising 5-55% by weight of an ethylene interpolymer, such as ethylene/vinyl ester, ethylene/unsaturated mono- or dicarboxylic acids or esters of said unsaturated acids, ethylene/.alpha.-olefin copolymers, etc.; 1-15% by weight of at least one plasticizer selected from the group consisting of processing oils, epoxidized oils polyesters, polyethers and polyetheresters; 20-90% by weight of cellulosic filler or mixture of cellulosic filler and mineral filler; 0-10% by weight of at least one additive, such as organic acid, organic acid derivative and surface active agent; and 0-27.5% by weight of elastomeric polymer.

Abstract: A leather-like textile material comprising a multi-layered substrate having at least first and second knitted or woven fabric layers, and a leather-like covering provided on one surface of the second fabric layer opposite to the first fabric layer. The first fabric layer is made of a material having a high water permeability, but a low water retentivity, and the second fabric layer is made of a material having a high water retentivity.

Abstract: A napped fabric is treated to bond the nap fibers together while leaving the nap structure largely open and porous. The surface of the bonded nap is then subjected to a series of spaced short cuts to form spaced clumps of bonded fibers which clumps have free ends projecting from the bonded nap so that they can be brushed from stable upright positions to bent-over positions, giving an attractive rough appearance resembling a split suede leather.

Abstract: A heat-moldable laminate comprising at least one thermoplastic resin layer, at least one fiber reinforced cured thermosetting resin layer, and at least one slippage layer interposed therebetween and bonding the resin layers, said slippage layer comprising a thermoplastic resin and said slippage layer being capable of being molten at lower temperatures than the moldable temperature of the thermoplastic resin layer, and a process for molding the heat-moldable laminate to produce a molded article having excellent strength and rigidity is disclosed.

Abstract: A weather-resisting extruded rubbery article based on carbon black-incorporated EPDM rubber substrate having on the surface thereof a thin layer of a colored rubbery material of a smooth or suede-like appearance integrally formed on the substrate by extrusion molding, characterized in that the colored rubbery material has been derived from 75-0% by weight of EPDM and 25-100% by weight of a graft copolymer of EPDM and vinyl chloride together with one or more coloring fillers.

Abstract: There is described a process for producing a novel porous fabric having at least 100,000 surface perforations per square inch by the biaxial stretching at ambient temperatures of a sheet of a composite fiber-film substrate formed by hot calendaring, inter alia, a laminate of a woven or non-woven web of fibers having a residual elongation of at least 40% and a synthetic polymeric film material constituting at least 20% by volume of the composite fiber-film substrate. Stretching of the composite fiber-film substrate is effected by passage through interdigitating grooved rollers having grooves spaced at a distance of less than one millimeter times the web basis weight in grams per square meter with concomitant control of the velocity of introduction of the composite fiber-film substrate into the nip of the grooved rollers to substantially the identical surface velocity of the grooved rollers.

Abstract: An artificial leather is made by impregnating a special nonwoven web substrate with an elastic polymer material. In another embodiment the substrate comprises a nonwoven fabric laminated to a woven or nonwoven fabric.

Abstract: A multilayer composite sheet useful as a substrate for artificial leather, comprises at least three fibrous layers, namely, a superficial layer (A) consisting of a spun-laid web composed of extremely fine fibers having an average denier of 0.5 or less and three-dimensionally entangled with each other; and intermediate layer (B) consisting of a web of staple fibers having a length of 50 mm or less and entangled together; and a base layer (C) consisting of a woven or knitted fabric, the above-mentioned three fibrous layers being superimposed on each other and combined together in such a manner that a portion of the fibers in each layer penetrates into the adjacent layers and becomes entangled three-dimensionally with the fibers in the adjacent layers.

Abstract: A laminated material is formed of a layer of polyurethane or polyether and a layer of extruded polyester. The polyester adhesive layer, which may contain five to fifteen percent by weight of polyurethane homogeneously mixed therein, is bonded to the layer of polyurethane or polyether under pressure at a sufficiently high temperature to permit an even viscous molecular flow between adjacent surfaces of the layers. When the layer is polyurethane, the temperature is above the softening point of polyurethane so that it is high enough to remove at least enough of the toluene solvent from the layer of polyurethane so that curling is prevented. When the laminated material is applied to a material with sufficient pressure and heated sufficiently that the layer of polyester becomes adhesive, the laminated material adheres to the material against which the layer of polyester is pressed.

Abstract: A bulky nonwoven fabric comprises fine fibers forming thin intertwined layers extending between one surface of the fabric and the other surface, that is, the layered fibers run in the direction of thickness of the fabric. The nonwoven fabric of thermoplastic resin is prepared by a melt-blowing process utilizing a drum collector and cooperating nip-roll. If desired the fiber and gas stream may be contacted with fine liquid drops.

Abstract: Hollow filaments having longitudinal grooves and ridges that are readily split along the grooves and are especially adapted for use in a flocking process to form flocked products with a surface similar to suede. The hollow filaments have a denier of about 0.8 to about 3.35 and have a void area of 15 to 30% of the total area of the cross section of the fiber.

Abstract: A process for the production of chemically bonded non-woven material, such as synthetic leather, is disclosed wherein a fiber fleece is impregnated with a heat sensitized polymer dispersion and the composition is destabilized to form a porous gel structure. Finally, the polymer is crosslinked at below 150.degree. C. and is dehydrated. Additionally, cut fibers of polyester of polyamide are formed into a fleece and an aqueous dispersion of butadiene-styrene coagulant and a curing composition is impregnated through the fleece. The binder is gelled and cured in superheated steam. The products obtained are soft and possess excellent physical and mechanical properties as well as superior dynamic stressability.

Abstract: A composite sheet material comprising a fibrous sheet which is impregnated and/or coated with a polyurethane elastomer, wherein said polyurethane elastomer comprises the reaction product of(A) a polymeric diol having a molecular weight of about 800-5000.(B) an organic polyisocyanate, and(C) a chain extender comprising a low molecular weight organic diol, and if desired,(D) a chain terminator; wherein more than 2 mol % of (C) and/or (D) comprise a hindered amine compound having the formula I ##STR1## wherein R.sup.1 is a substituent selected from the group consisting of hydrogen, oxygen, alkenyl, alkynyl, alkyl, aralkyl, acyl, --(R.sup.5 O).sub.n H and --(COR.sup.6 CO.sub.2 R.sup.7 O).sub.m --H, wherein R.sup.5 is an alkylene group, R.sup.6 is a residue of an organic dicarboxylic acid and R.sup.7 is a residue of an organic diol, n is an integer from 1 to 50 and m is an integer from 1 to 15;R.sup.

Abstract: A resin impregnated fibrous web is comprised of a needled fibrous batt and a polymeric resin distributed throughout the batt. The density of the impregnated web is uniform throughout with the bulk density of the web being less than the actual density of the web whereby the web is porous. The impregnated web has filaments which are both coated and uncoated with the polymeric resin. A method of forming the impregnated fibrous web is also disclosed.

Abstract: The disclosed composite fabric, useful as a substratum for artificial leather, comprises a woven or knitted frabic and at least one non-woven fabric firmly bonded to the woven or knitted fabric, and is produced by providing a precursory sheet with two or more layers from a woven or knitted fabric and one or more fibrous webs which consist of numerous extremely fine fibers having an average diameter of from 0.1 to 6.0 microns, and uniformly impacting the fibrous web surface of the precursory sheet with numerous fluid jets ejected under a high pressure of from 15 to 100 kg/cm.sup.2, at a ratio of a total impact area of the fluid jets on the precursory sheet surface to an area of the precursory sheet surface to be impacted of at least 1.