CA1080598A - Artificial leather and method of manufacture - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A laminate, suitable for use as a shoe upper material or for upholstery, consists essentially of a) a layer of permeable fabric made of interlaced multifibre yarns and having a flat upper face, the interlaced yarn structure of said fabric having a drape stiffness less than 21/4 inches and preferably at least 11/4 inches. b) a layer of water vapour permeable microporous elastomeric polymer having a density in the range of 0.3 to 0.4 g/cm3 and a thickness of 0.3 to 0.8 mm; c) an elastomeric adhesive bonding the lower face of said microporous layer to the upper face of said fabric, said adhesive being in contact with the upper surface of said fabric, and said fabric being substantially non-impregnated by said adhesive, and preferably d) a skin of film-forming flexible polymeric material, on the upper face of said microporous layer, having a thickness of up to 70 microns and a density of at least 1g/cm3..

Description

108V5'3~

Thi5 invention relates to a laminating process and to a laminate.
Synthetic lcather materials t-aving a fibrous backing are well known for use in making shoe uppers. Generally their outer, or top, face has a continuous layer of polymer material and the fibrous backing is a needle-punched impregnated non-wovenor a fabric comprising interlaced (e.g. woven) multifibre yarns.
Gne aspect of the invention makes possible the production of a laminate which simulates a shoe upper leather having a soft hand or feel and is very suitable for use as a shoe upper material. Other uses of laminates produced in accordance with this invention are, for instance, as upholstery materials.
According to the present invention there is provided a process for making a laminate consisting essentially of ~ a) a layer of permeable fabric made of interlaced multifibre yarns and having a flat upper face, the interlaced yarn structure of said fabric having a drape stiffness less than 2-1/4 inches, and preferably at least 1-1/4 inches;
i (b) a preformed sheet of water vapour permeable microporous elas-tomeric polymer having a density in the range of 0.3 to 0.4 g/cm and a thickness of 0.3 to 0.8 mm;
(c) an elastomeric adhesive bonding the lower face of said micro-porous layer to the upper face of said fabric, said adhesive being in contact with the upper surface of said fabric, and said fabric being substantially non-impregnated by said adhesive; which comprises adhering one face of a sheet of preformed microporous polymer, e.g. polyurethane or plasticized polyvinylchloride, which is less than 1 mm thick, to a temporary backer, and adhering the fabric to the other face of the said sheet of preformed micro-porous material by the application of an adhesive. This is conveniently ac-complished by applying to the other face of said sheet a thin deposit of an adhesive and, when said a& esive is in tacky condition, pressing thereagainst the fabric to mould said adhesive to the contour of the upper surfaces of exposed yarns of said fabric while keeping the structure of the fabric s~ub-108~:)59~

stantially non-impregnated and non-stiffened by said adhesive and then setting said adhesive and stripping off said backer from sald sheet of microporous polymer, said adhesive being one which sets from a tacky condition to a solid non-tacky elastomeric condition.
The said adhesive may be applied to said other face of the sheet of microporous polymer as a solution in a volatile solvent which is a swelling agent for said polymer.
Preferably, there is formed a skin of film-forming flexible poly-meric material, on the upper face of said microporous layer, having a thick-ness of up to 70 microns and a density of at least 1 g/cm3.
The laminating pressure preferably is applied momentarily to de-form said microporous layer to force yarns of said fabric, relatively, to-wards said adhesive deposit and thereby bring their upper portions into con-tact with said adhesive, said pressure then being released to permit said forced yarns to move away relatively with some adhesive thereon to form voids in said adhesive.
The said microporous polymer, which is preferably polyurethane, preferably is adhered to the said temporary backer by applying to the said backer a thin layer of a solution of elastomeric polymer in a solvent there-for and applying to said thin layer, while it still contains solvent and priorto solidification thereof, said sheet of microporous polymer and then removing said solvent from said adhesive layer.
In a preferred form of the process the said sheet of microporous polymer carries a coagulant for said solution in its micropores adjacent to said solvent-containing layer.
The said solvent in the said solvent carrying layer is preferably a volatile solvent and has an elastomeric polyurethane dissolved therein and said temporary backer preferably is "vinylt' release paper, the conditions of the process being such that if said coagulant were to be omitted said structure .,.~
'T -- 2 i. ,i ' ' . ,~ ~ ,;0~ 1 ~08V59~

would not be strippable from said backer without damage to said backer or said microporous sheet.
The invention also extends to a lasted shoe upper made from a mate-rial in accordance with the invention.
Certain suitable shoe upper materials produced in accordance with this invention are illustrated in the accompanying drawings in which:
Figures 1 to 8, 12, 15 and 16 are photomicrographs of cross-sections tthe embodiments illustrated in Figures 3, 4 and 12 being non-preferred in certain respects, as expiained below).
Figure 9 is a photomicrograph of a face of a fabric layer after the ~ -fabric has been stripped from the structure shown in Figures 1 - 8.
Figures 10 and 11 respectively are photomicrographs of each face of the fabric used to make the structures shown in Figures 1 - 8.
Figure 13 is a photomicrograph of the napped, impregnated face of the fabric used to make the structure shown in Figure 12.
Figure 14 is a photomicrograph of the napped face of another fabric.
;; Figure 17 is a photomicrograph of the napped, impregnated face of the fabric of the structure shown in Figures 15 and 16.
Figures 18 to 20 are photomicrographs of cut pieces of a product of Example 19, having an impregnated nap, taken (in various directions as de-scribed below) with a scanning electron microscope.
Figure 20A is a schematic view showing the cut edge of a sample and the angle at which it is viewed.
Figures 21 to 23 are similar views of another product of Example 19.
Figures 26 and 27 are photomicrographs, taken with an ordinary light microscope, of a product of Example 20 before and after an abrasion test; and Figures 24 and 25 are similar views of a similar product whose nap is, however, unbonded.
Figure 28 is a schematic view of a skiving operation.
Figures 1 - 5, 9, 12 - 13 weTe made with a scanning electron micro-. . .

108~)598 scope, as described, for instance, in United States patent 3,637,415 ~Civardi) column 5 line 71 to column 6 line 18.
Figures 6 to 8, 10, 11, and 24 - 27 were made with an ordinary light microscope.
In the embodiment illustrated in Figures 1, 2, 5 - 11 there is a layer of woven fabric 11, a layer of microporous elastomeric material 12, an elastomeric adhesive 13 bonding the lower face of the microporous layer to the upper face of the fabric and a skin 14 of film-forming polymeric material on the upper face of the microporous layer. It will be seen that the adhesive 13 is in contact with the upper surface of the fabric and that the fabric is sub-stantially non-impregnated by the adhesive.
More specifically, in the structure shown in Figure 1 the woven fabric is made up of multifibre yarns or threads running substantially trans-versely to each other (i.e. warp and weft threads). In Figure 1 the cross-sections of the yarns 21, 22, 23, 24, 25, running in a direction transverse to the plane of the picture, are evident, groups of fibres of other yarns (e.g.
yarn 27) running parallel to the plane of the picture are also seen. Figure 6 shows, more clearly, a warp yarn running parallel to the plane of the picture and the cross-section of five weft yarns ~running in a direction transverse to the picture). In Figure 7 (a cross-sectioD in a plane at right angles to that of Figure 6) a weft yarn runs parallel to the plane of the picture and the cross-section of several warp yarns are also evident.
Each yarn is made up of a number of fibres ~in this case the fibres are cotton staple fibres) arranged substantially parallel to each other and in cohering relationships. In the fabrics shown in the drawings the cohering re-lationshp of the fibres results from the fact that they are twisted together.
The fabric in Figure 1 is an unnapped cotton sateen having its "sateen face" (characterized by exposed lengths of warp yarns spanning several weft yarns) uppermost and in contact with the adhesive. There are 96 warp yarns per inch ~i.e. 38 per cm) and 64 weft yarns per inch (i.e. 25 per cm).

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The weave pattern is S harness 4/1 satin weave; thus each of the exposed lengths of warp yarns at the upper face spans four weft yarns as can be seen in Figure 10, while on the opposite face (Figure 11) there are exposed lengths of weft yarn each spanning four warp yarns. The warp yarns have a count of 18.5 and a Z-twist of 4.21 turns per inch and the weft yarns have a count of 12.5 and a Z-twist of 3.78. ("Count" is cotton count, referring to the number of 840-yard hanks per pound). The fabric has an elongation at break of about ~-10% in the warp direction and about 15% in the weft direction (measured before lamination). Its thickness is about 0.5 mm.
As indicated, the sateen fabric in Figure 1 has a flat (i.e. sub-stantially un-napped) face in contact with the adhesive. Like practically all fabrics made of staple fibre yarns, it does have isolated individual fibre ends projecting from each face, but the number of such fibres is small, well below about 2000 per square inch of face (i.e. below about 300 per square cm.) generally below about 1500 per in2 (i.e. below about 250 per cm2), and the ~ -projecting fibres are of uneven exposed length.
As seen in Figure 1 the adhesive deposit is quite thin. In the structure shown in Figure 1 the distance between the top of the yarn 23 and the bottom of the microporous layer 12 is well below 0.05 mm, e.g. of the order of 0.01 to 0.02 mm, and that between the yarns the adhesive deposit on the bottom surface of the microporous layer may be just as thin, or even non-existent. In the structure shown in Figure 1 although the adhesive in that embodiment is moulded to conform to the upper portions of the yarns and ex-tends down along the sides of those upper portions it did not fill the spaces between the yarns to any significant extent. Thus, in the structure shown in Figure 1 the voids 31, 32 between the yarns are largely free of adhesive (the total of the thicknesses of the downwardly extending adhesive fingers 36, 37 is considerably less than ~ of the shortest distance between the yarns 21, 23).
This is borne out in the structure shown in Figure 6 ~in which the space 38 between the very uppermost portions 39, 40 of the warp yarn 41 is largely free 108059~

of adhesive) and in Figure 7 (which indicates spaces 42 largely free of adhe-sive above the tops of most of the visible warp yarn cross sections). Figure 7 also indicates that the weft yarn makes very little contact with the adhesive layer; at the centre of Figure 7 there appears to be a finger of adhesive 43 extending downward into adhesive contact with the uppermost portion 44 of the weft yarn. This is confirmed in Figure 6 in which there is an open space be-tweenthe adhesive layer and the top of the visible weft yarn 46 that lies over the warp yarn.
Figures 1 and 5 also indicate that there is no significant penetra-tion of the adhesive into the individual yarns; apparently the spaces between adjacent fibres (of the bundle of fibres making up each yarn) are so small that the adhesive comes into contact ~and bridges) only those fibres which happen to be outermost ~and uppermost) at the zone where the adhesive contacts the yarn.
It will also be understood that, because of the twist in the yarns and the length of the fibres a given fibre will be in contact with the adhesive (at the ; outer upper surface of a yarn) for only a portion of the length of that fibre, and generally for only a minor portion of its length; for the remainder of its length that fibre will be located within the yarn away from its surface, or si-tuated at another surface of the yarn, or situated in that length of yarn which is buried, and not at the upper face of the fabric. (Staple fibres are typical-ly over 2 cm long and thus would generally extend over several repeated "buried"portions of the yarn; continuous fibres are of practically infinite length).
Figures 1 and 5 indicate t~at very little, if any, of the adhesive serves to bond yarns directly together, although, of course, it does serve to bond all or part of the yarns together indirectly, by bonding them individual-ly to the microporous layer; thus the adhesive does not markedly stiffen the fabric as would be the case if it bonded adjacent yarns directly to each other.
Some of the adhesive may adhere to portions of the yarns that are spaced from the adhesive layer on the microporous layer 12 and such adhesive may be pres-ent, and bridge, some yarn cross-over points 100, as indicated at the left of 108~)598 Figure 8.
The strength of the bond between the fabric and the microporous layer is about 8 to 12 pounds per inch or more (Instron tested, ASTM-D-751-68).
When the fabric is stripped mechanically from the rest of the laminate (as by grasping an exposed edge of the fabric and peeling off the fabric)~ the ad-hesive remains substantially on the microporous layer and the stripped fabric is largely or substantially free of the adhesive and retains substantially its original pliability. Figure 9 indicates that some adhesive may remain on the very top surface of the yarns of the fabric after stripping.
In Figure 1 the structure of the microporous layer 12 is substantial-ly the same as that of the microporous layer shown in Civardi United States 3,637,415 at Figures 1 and 3 and at the lower right of Figure 4 of the patent.
The said layer (and its method of manufacture) is described in the specifica-tion of that patent ~particularly the "less dense upper layer" of its Example

2). The layer is about 0.020 inch ~i.e. about 0.5 mm) thick, its density is about 0.35 g/cm3, and its tensile strength is in the range of about 7 to 10 pounds per inch of width and its elongation at break is in the range of about 150 to 250%. It is substantially isotropic ~e.g. the ratio of the modulus ~at 10% elongation) in any two longitudinal directions at right angles to each other is within the range of about 0.75:1 to 1.25:1). It is of substantially uniform density throughout its thickness and is of substantially uniform ~hick-ness. It is composed of a thermoplastic elastomeric polyurethane, soluble in dimethyl formamide, of the type described in Civardi United States 3j637,415 column 4 line 1 to column 5 line 47. In this particular embodiment the micro-porous layer has a tensile set ~measured as described below, after 100% elonga-tion) of above 10% ~e.g. in the range of about 10 - 30% such as about 20%) one minute after the release of stress and above 5% ~e.g. in the range of about 5 - 15%, such as about 10%) one hour after the release of stress; thus in one measurement the following tensile set values were obtained for the times, after the release of the stress, given in parenthesis: 27% (10 seconds after 108~598 the release of the stress); 20.8% ~1 minute); 19.8% (2 minutes); 17.7% ~5 minutes); 14.6% ~lO minutes); 12.5% (30 minutes); 11.5% ~60 minutes after release of stress).
The measurement of tensile set may be made on a specimen of the microporous layer, prior to laminating, as follows: a specimen ~ inch wide and about 6 inches long is marked with bench marks 3 inches apart. The speci-men is stretched in an Instron tester so that the bench marks become 6 inches apart. (100% elongation) in a period of 15 seconds. The specimen is then held at 100% elongation for 10 minutes. Shortly upon release (about 10 sec.
thereafter) the distance between marks is measured and the measurement is re-peated at predetermined time intervals while the sample is maintained in an unstressed condition. The entire test is carried out at 22C and 60 - 65%
R.H. It will be understood that percent set is calculated by subtracting the original distance between bench marks (i.e. 3 inches) from the measured dis-tance at the predetermined time after release of stress, dividing the result-ing figure by the original distance (i.e. 3 inches) and multiplying by 100 to get the result in percent.
In the material shown in Figure 1 the skin 14 is a relatively dense layer of polyurethane having little or no porosity visible at 1000 magnifica-; tion, as can be seen from Figure 2. Its density is well above 0.6 g/cm3. It has a thickness less than 20 microns, e.g. about 10 microns; the surface of the skin has a grain texture resembling that of leather, with small hills and valleys and the thickness of the skin is thus non-uniform. The whi~ish por-tion 48 shows the surface of the skin (rather than its cross-section) as viewed at a low angle.
The laminates of this invention have given excellent results when tested for use as the shoe upper material in shoe-making trials with both ~ ;~
men's and women's shoes. They are soft and comfortable in use and show an excellent fine leather-like break. In the shoe-making process, they have been found to be easy to cut into the desired shapes of the individual shoe parts 108~)S9~

(such as the vamp and quarter of a woman's cement shoe) with standard machin-ery, such as a USM clicker using a wooden cutting block. They stitch well and are lasted readily, using conventional lasting pressures and tensions and con-ventional steaming of the upper and can be heat set in conventional manner to obtain good shoe-shape retention (e.g. about 50%, generally above 60%, reten-tion). The lower edges of the lasted uppers can be cemented readily to the shoe bottoms by conventional techniques; one such technique involves roughing to remove all or part of the skin layer from the portion to be cemented and then cementing with conventional polyurethane shoe cement; another such tech-nique involves string lasting and injection molding a thermoplastic shoe sole ~of, say, vinyl resin or polyurethane commonly used for that purpose~ directly into bonding contact with the unroughened surface of the skin. The shoes show excellent shape and shape retention and general appearance and are soft to the touch.
A structure of the type illustrated in Figure 1 has shown the follow-ing properties: Taber Wear Index (CCC-T-1916-Method 5306, H-22 Wheel, 1000 gm load) first sign of wear occurs at 130 cycles, weight loss at 1000 cycles is 267 mg; Crock (AATCC Method 8-1961 at 100 double strokes) 4 dry, 5 wet;

Wyzenbeek Abrasion (CFFAO 2b, with Stainless Steel screen, 2 lb. pressure, 61b. tension 25,000 cycles), passed in both directions (i.e. machine direction, "MD", which is lengthwise of the laminateJ and cross machine direction, "XMD", which is transverse to the machine direction); Adhesion ~of fabric layer) ~ lb./in. ~ASTM D-751-68 1 in. strip, 12 in./min.) lO.O MD, 9.5 XMD; Satra Flex ; ~O C, 18,000/hr) passed even after 40 hours, Tear, tongue, lb. ~ASTM D-751-68 12 in./min.) 5.5 MD, 8.4 XMD; Tensile, Grab, lb., ~ASTM D-2208-64) 121 MD, 107XMD, 210 diagonal; Elongation % (ASTM D-2208-64) 26.6 MD, 11.0 XMD, 62.6 Diagonal; Blocking (CFFA-5, 2 in.x2 in. sample 150F with 1 lb. wt., 30 min.), no. l; Grain Retention (10 min. @ 260F), pass; Water Vapor Transmission (Honeywell MVT tester ASTM E-96-66 Procedure) 25.5 gm/m hr; pliability (Tinius-Olsen 1 in. sample width, ~ in. span, .080 wt. moment with readings ~ _ 9 _ 108~)S9~

taken at 30 angle of deflection with the skin uppermost and therefore being under compression in this test) 36MD, 27.5 XMD. The structure also has ex-cellent strength and stability on the bias.
The structure shown in Figure 3 is substantially the same as that shown in Figure 1 except that there is a difference in the nature and thickness of the skin. The water vapor transmission of this product is lower than that shown in FiguTe 1 and its flex life is lower. It has higher abrasion resis-tance. More details of the fabric construction are evident in Figure 3 be-cause of the position at which the particular cross-section was made. Figure

3 also indicates an occasional projecting fibre 62 extending upwards from yarn 63 into the adhesive o4; similar projecting fibres are also seen in Figures 5 and 6. Incidentally, the difference in the appearance of the microporous layer 66 in Figure 3 is believed to be due to distortions owing to the method of cutting the sample. The skin layer is shown at 67 in Figure 4 and its grained textured surface is indicated by the lighter portion at 68.
Another aspect of this invention relates to a process for making a laminate of the type described above. In one particularly suitable technique, the skin is formed, wholly or in part, by coating a solution of the skin mate-rial onto the surface of a temporary support ~such as release paper) which is of such nature as to permit subsequent stripping mechanically therefrom with-; out damage to the skin. While the coating is in a tacky condition, a micro-porous sheet is placed in contact with it and bonded to it and solvent is re-moved from the skin layer; thereafter the adhesive is deposited on the free surface of the microporous sheet, the fabric is placed in contact with the adhesive, and the resulting laminate is stripped from the support. The support may have a smooth glossy surface, giving the product a "patent leather" finish.
The support may also have a textured surface, simulating a selected leather grain, for example; this texture is imparted to the skin and is exposed on strlpping .
In the technique described above, in which a solution of the skin .,, ,- ':

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material (or a portion thereof) is first applied to a temporary support, the water vapor permeability of the skin (and thus of the entire product) may be increased by first wetting the contacting surface of the microporous sheet with a coagulant for said solutionJ e.g. a material (such as water) which is miscible with the solvent of the solution (e.g. dimethylformamide) and which is a non-solvent for the dissolved skin material ~e.g. polyurethane). The product shown in Figures 1 and 2 is made by this technique, while that shown in Figures 3 and 4 is made without the use of a coagulant. The coagulant is preferably one which is substantially inert to the material of the microporous ; 10 layer and does not degrade its structure under the conditions employed in the process.
One significant process aspect involves applying the fabric to a tacky adhesive on the surface of the thin elastomeric microporous layer while the latter is maintained in adherent, but strippable, relationship with a di-mensionally stable backing, such as the release paper. By this procedure im-pregnation or penetration of the adhesive into the interstices of the fabric is diminished and stiffening of the fabric is thereby reduced or avoided; also ~' there is less tendency for surface roughening or fabric show-through during stretching in the lasting operation. The presence of the dimensionally stable ` 20 backing contributes to this and to the production of a uniform attractive pro-duct, inhibiting deformation of the thin low density elastomeric microporous layer during the laminating process. Other dimensionally stable backings may be employed instead of the release paper. Thus a rigid temporary backing may be used. For example, the microporous thermoplastic polyurethane layer tends to soften and adhere to a hot metal (e.g. carbon steel) surface (e.g. having a ; temperature of about 145 - 165C); the microporous polyurethane sheet may be fed continuously into contact with a rotating hot metal roll so that one face of the microporous sheet adheres to the surface of the roll, the adhesive may be applied to the other face of the sheet and, when the adhesive has reached a tacky condition and while the sheet is still on the roll, the fabric may be - 11 - .

10~0598 fed continuously into contact with the tacky adhesive, after which the assembly (of fabric-adhesive-microporous layer) may be stripped off the roll.
The adhesive is preferably an elastomeric polyurethane. Adhesives of this type are commercially available. Thus one may employ one of the well known "two package" adhesive comprising a polymer having terminal hydroxyl groups such as a polyester or polyether as one component and a polyisocyanate reactive with those hydroxyl groups as the other component, the components be-ing mixed just before use and reacting to form a high molecular weight elasto-meric cross-linked polyurethane in situ. One or both of the components is usually supplied in solution in an inert volatile solvent (e.g. ethyl acetate or acetone) and the reaction may be accelerated by adding a catalyst for the reaction, as is well known in the art. The solvents employed generally also act as swelling agents for the microporous layer; thus if the solvent-contain-ing adhesive is applied, in the same amount as used in the process of this in-vention, to the thin microporous sheet the latter swells and distorts exten-sively teven though the linear polyurethane of the preferred microporous sheet is insolublein the swelling solvent), but when the microporous sheet is first bonded to the release paper or other solvent-resistant backing such distortion does not occur, the distorting tendency resulting from the swelling being re-sisted by the releasable bond between the backing and the microporous sheet.
The solvent-containing adhesives generally contain an amount of solvent such that the adhesive flows readily during its application to the microporous layer. It is preferable to remove some of the solvent (as by eva-poration) to increase the flowability of the adhesive and increase its tack before the fabric is pressed against the adhesive, so that the adhesive is brought to a stage in which the laminating pressure acts to mold the adhesive into firm contact with the adjacent outer yarn surfaces without causing pene-tration and consequent stiffening of the fabric layer. The laminating pressure may be exerted in any desired manner; conveniently the assemblage of fabric, microporous layer and release paper is passed through the nip between a hard-10~)598 surface ~e.g. metal) roll and a roll having a more yielding surface (e.g. a rubber-covered roll) so that the laminating pressure is exerted substantially uniformly across the area of the assemblage. Thereafter any remaining solvent -may be removed and curing (i.e. reaction to higher molecular weight) of the adhesive can be effected. Usually the release paper is not stripped off until the adhesive has been at least partially cured to a stage at which the forces ' exerted in the stripping operation will not substantially affect the adhesive bond between the fabric and the microporous layer.
The appearance of the adhesive in the structure shown in Figures 1, 3, 5 and 8 indicates that the momentarily exerted laminating pressure result-ing from the passage of the assemblage through the nip of the pair of rolls squeezes (and defor~s) both the fabric layer and the microporous layer so that portions of its yarns near the upper surface of the fabric are pressed momen-tarily against the adhesive layer and that thereafter the fabric and micropor-ous layer tend to recover to their undeformed condition of that said yarn por-tions retract, relatively, carrying with them some of the adhesive, removing it from the layer on the microporous material, leaving substantial voids between this fabric-carried adhesive and said adhesive layer. These voids are general-` ly not closed cells; they communicate with the numerous air passages through the fabric. Such removal of adhesive reduces the effective thickness of said layer and increases its capacity for transmitting moisture vapor.
For small scale, or laboratory operation, the tackiness of the ad-hesive just prior to exertion of the laminating pressure may be easily control-led by a simple finger test, in which one permits the solvent to evaporate from the adhesive layer and then places one's finger lightly on the surface of the adhesive and then draws the finger away; excellent results have been ob-tained if laminating is effected immediately after the finger is found to stick firmly to the layer (being "grabbed" thereby) so that the finger drawn away only by exertion of some force (like that encountered when applying the same test to the adhesive surface of conventional Scotch brand transparent Trademark 108V59~

pressure sensitive tape). In large scale practice, the conditions of evapora-tion prior to passage through the nip can be accurately controlled, as by pas-sing the material, directly after application of the adhesive and while the adhesive-coated material is traveling to the nip, through a suitable housing provided with an evaporative atmosphere having a controlled rate of flow, com-position and temperature. At the start of operation the initial settings for control of the evaporative atmosphere may be made readily by trial-and-error (such as by the use of the finger test or by microscopic inspection of the final product, followed by appropriate adjustment of the evaporation condi-tions); e.g. increase the evaporation (as by increased temperature or longer time) if the adhesive is stringy just prior to laminating, allowing the finger to be pulled away easily, and decrease the evaporation if the adhesive no longer sticks to the finger. ~t will be understood that in the preferred em-bodiment the lamination occurs under substantial pressure such as to mold the adhesive, this is a pressure considerably greater than is present when there is light contact, i.e. greater than so-called "kiss pressure".
The release paper may be one of the known commercial types, which are coated papers whose coating contains a release agent such as a silicone.
The adhesion between the release paper and the microporous layer should be such that the forces induced by the swelling of the microporous layer (owing to the effect of the solvent-containing adhesive, as discussed) do not cause separations between the release paper and the microporous layer. This adhesion depends, for instance, on the character of the coating of the release paper (e.g. release paper having a heavier coating, freer of discontinuities, gives less adhesion) and on the time and temperature of treatment during removal of solvent of the skin layer of the laminate. The optimum conditions can be de-termined readily by routine trial-and-error following the teachings herein.
Thus for the embodiment (described previously) in which a coagulant-bearing (e.g. pre-wet) microporous sheet is used, the effect of the presence of the coagulant is to decrease the tendency of the skin layer to adhere to the re-lease paper; in that embodiment we have found that it is best to use a more lightly coated paper having more discontinuities in its coating, such as a release paper that is customarily used as a temporary backer for highly viscous vinyl plastisols, i.e. a paper well known in the trade as "vinyl paper" (e.g.
the product known as "Transkote FER" made by S.D. Warren Co. division of Scott Paper Co.). Such vinyl paper is generally not employed in the art as a release paper for polyurethane solutions since the latter conventionally tend to be-come so strongly bonded thereto that, on stripping, portions of the release paper or of the polyurethane deposit tend to be pulled off. It is also within the broader scope of this invention to use backers which carry less release agent than vinyl paper in the embodiment in which coagulant is present, partic-ularly when appropriate adjustment is made in the conditions of removal of solvent from the skin layer.
In an embodiment in which a pre-wet microporous sheet is employed, the prewetting may be effected by saturating the thin sheet with water and then pressing it to remove most, or substantially all, of the water that can be removed by mechanical expression. For instance, the sheet may be placed loose in a vessel containing a dilute solution of a surfactant ~e.g. in less than about 0.1% concentration, such as O.01 to 0.05% of Aerosol OT) in warm water ~e.g. at about 40 to 60C) and allowed to soak until the amount of water taken up approaches the saturation value (for the microporous sheet shown in Figures 1 - 3 the saturation value is above 150% of water based on the original, unsoaked, weight of the sheet). The wet sheet is then passed through the nip between a rubber roll and a steel roll which are urged together under relative-ly high pressure, e.g. 30 - 80 pounds per lineal inch of nip; the sheet then has a water content of about 80 to 100% ~again, based on the original weight of the unsoaked sheet). Such a sheet may then be applied to the solvent-containing skin layer on the release paper, as described. In the procedure just described the coagulant (water) is present inthe interior of the micro-porous sheet as well as in its surface zones. We have found that excellent `;

*

Trademark 108S)598 results are also obtained when the coagulant is present in only the surface zone to be placed in contact with the solvent-containing solution. For in-stance, a surfactant-containing solution may be applied to the upper surface of the sheet (the sheet being in substantially flat, horizontal condition) and allowed to penetrate thereinto for a short time (as low as 10 seconds for in-stance), after which the excess unabsorbed water may be removed as by a squeegee, giving a water content ~again based on the original weight of the sheet) of more than about 5%, e.g. about 10 to 60%; the water-treated surface of the sheet may then be laminated continuously to the solvent-containing skin layer. The optimum water content depends to som0 extent on the properties of the microporous sheet, such as its rate of water absorption, and may be deter-mined by routine trial-and-error with the teachings of this application in mind.
Particularly preferred products of this invention are laminates com-prising a) a fabric having a flat upper face, a drape stiffness of less than 2~ inches, preferably less than 2 inches ~Cantilever test 30 angle, ASTM D-1388-64), a thickness of 0.3 to 0.8 mm, e.g. 0.4 to 0.6 mm, such as about 0.5 mm, a grab tensile strength of above 75 pounds ~ASTM D-1682-64);
b) a layer of microporous elastomeric polyurethane having a density in the range of 0.3 to 0.4 g/cm3, a water-vapor permeability of at least 150 g/m2/hr ~ASTM E-96-66), a cohesive strength of at least 12 lbs. ~and more pref-erably at least 20 lbs.) per inch of width, ~cohesive strength is measured by strongly adhering each face of the layer to a strong flexible supporting fabric, as by means of an adhesive which does not damage the structure of the layer and then pulling the adjacent ends of the supporting layers apart at a speed of, say, 12 inches per minute in a suitable physical testing apparatus, such as a Scott or Tinius Olsen tester) and a thickness of 0.4 to 0.5 mm;
c) an elastomeric a& esive bonding the lower face of said microporous layer to the upper face of said fabric, said adhesive being in contact with ;

108~)598 the upper surface of said fabric, and said fabric being substantially non-impregnated by said adhesive, and d) a skin of film-forming flexible polymeric material, on the upper face of said microporous layer, having a thickness of up to 70 microns, preferably 10 to 50 microns, and a density of at least 1 gram per cm3.
Products having thinner skins show a finer, more subtle "break" but generally do not have as high a resistance to abrasion; thus a product having a skin thickness of say about 7 microns is more suitable for use as an upholstery material ~i.e. as the outer surface of upholstered furniture) than as a shoe upper material. A graph of the density gradient across the thickness of one preferred type of laminate, starting with the skin layer, shows a density above 1 g/cm3 ~e.g. in the range of about 1 to 1.4) for a distance substantially equal to the thickness of the skin, then a relatively constant density of 0.3 to 0.4 g/cm3 for a longer distance, substantially equal to the thickness of the microporous layer, and then a density averaging roughly 0.2 to 0.4 g/cm3 for a distance corresponding substantially to the thickness of the fabric.
In the product illustrated in Figures 1 - 3 the fabric layer is of cotton sateen. It will be understood that other fabrics may be used. Such fabrics may be made of yarns or threads of staple fibres, such as cotton, polyester ~e.g.polyethylene terephthalate), nylon ~e.g. nylon-6- OT nylon-66) or blends thereof ~e.g. 50/50, 25/75 or 75/25 blends such as of cotton poly-ester~ or of continuous filaments (e.g. polyester or nylon). The fabric may be of the woven type or the knitted type. In either case the fabric should have an elongation at break of at least 5%, preferably at least 7% in each direction. For example the elongation at break of the illustrated cotton sateen fabric ~before lamination) is about 15% ~in the weft direction) and x 10% ~in the warp direction), while the elongations at break for the polyester-cotton fabrics illustrated herein are over 20% ~e.g. 3~ or 40%) in each direc-tion. In the most preferred form of the invention the yarns of the fabric are substantially unimpregnated and substantially free of sizing. In any event, - 10~059~

the type and degree of sizing or other non-fibrous material is not such as to raise the stiffness of the interlaced yarn structure of the fabric to more than 2 1/4 inches (Cantilever test, ASTM-1388-64). The fabric has at least one flat ~i.e. substantially unnapped face), which is in contact with the adhesive. The other face may be flat or napped. The use of napped fabrics constitutes an especially preferred aspect of the invention and will be described at a later point in this specification.
The microporous layer is preferably substantially isotropic as pre- ~-~
viously indicated; it is, however, within the scope of the invention to use anisotropic layers.
The polyurethane material of which the microporous layer is composed is preferably of the type described in Civardi United States 3,637,415 issued January 25, 1972, column 4 line 1 to column 5 line 47. Cycloaliphatic or aliphatic diisocyanates may be used as all or part of the diisocyanate con-tent, and the proportion of diisocyanate may be such as to give a nitrogen ~ ;
content of say 3.5 or 3.8%, for instance.
It is within the scope of the invention to use microporous poly-urethane layers whose cavities are of smaller or larger size than those shown in Figures 1 to 4 of Civardi United States 3,637,415. Such products may be made, for instance, by using water-soluble salt particles of smaller or larger size in the polyurethane-solvent salt paste the coagulation of which produces the microporous layer. Alternatively the microporous layer may be produced by the techniques described in Civardi United States patent 3,590,112 issued June 29, 1971 at column 3, line 29 to column 4 line 11. Preferably a cross- ;
section of the microporous material shows numerous voids, at least 1 micron in diameter, occupying more than 50% of the area of the cross-section.
It is preferred that the microporous layer be of substantially uni-form density throughout its thickness. It is, however, within the scope of the invention to use a microporous layer having two or more sub-layers of different density. For example, one may, less preferably, use a sheet obtained by slic-:. . ..

~08~598 ing the unfinished two-layer sheet described as the starting material of Example 2 of United States 3,637,415 integrally attached to about 0.1 mm of the adherent denser layer; if the resulting sheet is then employed in the production of the laminate of this invention, with the denser layer of the microporous sheet facing the fabric, the laminate will be somewhat stiffer than when the microporous sheet has the same total thickness but is, uniform-ly, a single layer of said less dense structure. The same "slice" may be used in the laminate, with its denser layer adjacent to the skin (giving improved abrasion resistance to the product and modifying its break). It will also be understood that the processes of this invention may also be used with more dense microporous elastomeric layers, e.g. layers having densities of about 0.5, 0.6 or 0.7 g/cm3 or with microporous materials which are cross-linked and not thermoplastic and which show much lower tensile set values.
In the structure of the product illustrated in Figures 1, 3, 5 and 8 the adhesive layer is substantially continuous, but the bonds to the fabric are spaced apart, with portions of the adhesive layer between these spaced bonding areas being out of contact with the fabric and not contributing sub-stantially to the adhesion; the adhesive material adheres strongly to the microporous polyurethane, and the portions between the spaced bonding areas are unnecessary for providing the adhesion between the microporous polyurethane and the fabric. It is within the scope of this invention to use a discontinu-ous adhesive, as by intaglio printing a pattern of spaced dots of adhesive onto the face of the microporous sheet (and then, while the adhesive is in active condition, bringing the fabric into contact with that face). The distance be-tween the tops of the yarns at the flat face of the fabric and the bottom of . the microporous layer is preferably less than 0.1 mm and more preferably well below 0.05 mm.
It is within the scope of this invention to produce the laminate without employing a temporary backer. In such case it is preferable to apply the adhesive in a form substantially free of solvent having a swelling action . .

on the microporous sheet. Thus one may employ a hot melt polyurethane ad-hesi~e applied hot to the microporous sheet; the fabric may be laminated to the hot adhesive, either immediately or after the latter has been cooled some-what to increase its tack. It will be understood that the microporous sheet need not carry a skin layer at the stage at which it is attached to the fabric.
When the skin layer is not present on the microporous sheet, it may be applied to the microporous sheet fabric composite by known techniques, such as by using the surface finishing treatments described in Civardi United States patent 3,637,415 or in Civardi and Kuentsler Canadian patent no.
948,498 dated June 4, 1974 or in Hull United States patent 3,689,629.
The skin layer may receive additional finishing treatments. For example the skin may be built up further by depositing additional finishing material on the skin side ~e.g. by spraying) after stripping off any temporary backer which may have been used, for instance material to give an "aniline" or tone-on-tone effect (as described in Canadian patent no. 948,498 may be applied as by spraying or by roller ~e.g. an intaglio roller, having very small close-ly spaced depressions for carrying the coating material to the surface to be coated). Designs may be applied by printing, e.g. with a pigmented solution of an elastomeric polyurethane. Also the skin layer may be modified by heat treatment, with or without pressing, as by hot embossing (by which the micro-porous layer may also be permanently deformed in desired pattern) or by a smoothing contact with a hot surface. Other finishing treatments such as those described in ~nited States patents 3,481,767 and 3,501,326 may be used.
The laminate may be hot boarded or "milled" to produce a material having the wrinkled fine grain appearance of milled leather. For instance the laminate ~after stripping off any backer used) may be heated in an oven at, say, about 150C and then, while still hot, it may be doubled over, with its skin surface inside, and pressure may be exerted at and near the fold line ; while the fold line is moved back and forth along the length of the material and while changing the fold so that the movement occurs along various fold ~08~)598 lines so as to cover the whole area of the piece.
As mentioned above, the bottom face of the fabric may be napped and the napped fibres may be then bonded together. For example, a fabric may be napped on one face, in conventional fashion as by passing it in contact with moving napping elements such as bristles or hooks ~such as a high speed counter rotating wheel having such napping elements projecting therefrom to raise or tease out fibres from its yarns). In the case of a woven fabric moving in the warp direction and subjected to oppositely moving elements, the nap fibres will originate mainly from the weft yarns which run transversely to the direc-tion of movement of the napping elements particularly when the face being napped has a preponderance of exposed weft yarns. The resulting nap is prefer-ably a mass of fibres which lie in all directions, and having substantial com-ponents lying generally parallel to the main plain of the fabric. Usually the nap includes a significant proportion of fibres whose ends are not visible at the napped surface such as fibres whose both ends are buried within a yarn and whose intermediate portions arch through the nap zone. It should be noted that conventional staple fibres are generally at least 2 cm in length, and thus much longer than the exposed length of a yarn at the surface of the fabric (which exposed length is generally less than about 1 mm). Thus if the napping elements pull a length of even 1, 2 or 5 mm of a given fibre from an exposed yarn, one or both ends of that fibre will still be anchored in, and twisted with, the other fibres of that yarn. Less preferably, the nap may be sheared in conventional fashion, for example, so as to cut any fibres which may have been raised ~e.g. at right angles to the plane of the fabric) to such an extent as to project significantly from the main nap zone. Figure 14 is a plain view of the face of a napped and sheared fabric ~specifically a 4/1 sateen weighing about 8.5 ounces per square yar~ (290 g/m ) and composed of yarns of a blend of 75% polyester (i.e. polyethylene terephthalate) and 25% cotton with 60 filling yarns per inch and 60 warp yarns per inch, napped on the face having a preponderance of filling yarns). The extent of napping is preferably such that 108~59~

a substantial, but generally minor, proportion of the weight of the fibres is brought into the nap zone; for example about ~ to 1 ounce or more of fibre per square yard in the nap for a fabric weighing about 6 to 9 ounces per square yard. Generally the weight proportion of the fibres brought into the nap zone is about 1% such as about 2 to 5 to 20%, preferably in the range of about 2 to 10 or 15%, of the total weight of the fabric (the nap fibres generally are anchored in, and teased from, the weft yarns and accordingly, for fabrics in which the weight of weft yarns is about equal to the weight of the warp yarns, the weight proportion of the weft yarns in the nap is 2 or 10 to 40%, such as about 4 to 30%, e.g. about 10 to 20%. It is preferably not such as to so weak-en the fabric, by removal of fibres from its main load carrying zone, that its strength ~and thus the strength of the laminate) will be below the level needed for the intended purpose.
The face of the fabric to be napped may be given an abrading treat-ment, e.g. with sandpaper, before napping, to sever some fibres at the exposed surfaces of the yarns.
The bonding of the nap fibres may be effected in various ways. In one preferred embodiment bonding is effected while substantially maintaining the nap in its open, low density state. For instance, the nap may be impregnat-ed with a latex, such as a flexible acrylate polymer ~e.g. polymerized ethyl :
acrylate or copolymers thereof) before or after lamination, taking care to a-void or minimize impregnation of the main fabric structure composed of inter-; laced multifibre yarns. A product of this type is illustrated in Figures 12 and 13, in which the fabric is a 4/1 sateen weighing about 6.5 ounces per square yard (220 g/m ) and composed of yarns of a blend of 75% polyethylene tereptha-late and 25% cotton, with 44 weft yarns per inch and 80 warp yarns per inch, the weft yarns having more fibre than the warp yarns, napped on the face having a preponderance of weft yarns, having its nap impregnated (prior to lamination), as with a latex of a flexible acrylate polymer, followed by evaporation of water from the latex, the amount of polymer being only a minor proportion (e.g.

.: ' ' . . ' ';, , 108~)S9~

5%) of the total weight of the fabric. In the structures shown in Figure 13 ~compare Figure 14) the deposited polymer bridges and bonds together nap fibres at spaced zones (e.g. 71, 72) along their lengths, and also forms occasional nodules thereon. The use of an aqueous latex is especially suitable when the nap comprises a high proportion (e.g. at least 50%) of highly water-absorbent fibres, such as cellulose fibres. The latex may be of a conventional elastomer such as diene homopolymer or co-polymer, e.g., rubbery butadieneacrylonitrile co-polymer which may be cross-linked as by vulcanization after impregnation.
For other fibres, such as polyester fibres9 it is often more desirable to ap-ply the bonding agent in solution in volatile organic solvent, although either technique may be employed for either or both types of fibres. Typically the amount of bonding agent is within the range of about 5 to 20% or more, e.g.
50 or 60% of the total weight of the fibre of the fabric, depending on the proportion of the fabric in the nap and the thickness of the nap; the weight ratio of bonding agent to fibre in the nap may be, say, about 0.4:1, 1:1, 2:1, 5:1, 10:1 or 20:1.
Another way of bonding the nap fibres is by applying a thin layer of polymer to the surface of the nap. Figures 15 to 17 illustrate one such embodi-ment, in which the fabric is a 4/1 sateen weighing about 6.5 ounces per square ~220 g/m2) and composed of yarns of a blend of 75% polyethylene terephthalate and 25% cotton, with 44 weft yarns per inch and 80 warp yarns per inch, the weft yarns having more fibre than the warp yarns, napped on the face having a preponderance of weft yarns, to which a layer of a solution of two-component cross-linking elastomeric polyurethane was applied to the nap (after lamination)by knife-coating followed by evaporation of the solvent and curing by heat, the amount of polyurethane so deposited being about 10 g per m . Prior to this treatment of the nap the measured thickness of the laminate was about 1.0 mm, while after the treatment it was about 1.2 mm ~as measured with a standard gauge used for measuring the thickness of leather, e.g. an Ames gauge, which exerts a compressing force on the sheet whose thickness is being measured);

108~598 thus~ the thickness of the nap zone is over 0.2 mm. Other methods of bonding the individual nap fibres together at spaced points will be apparent to those skilled in the art. Thus it is within the scope of the invention to effect such bonding by suitable heating and/or solvent treatment, to tackify at least some of the nap fibres, and to bring them together, if neccessary, to cause bonding.
It is also within the scope of the invention to carry out all or part of the napping afte~ the application of the bonding agent and before the set-ting thereof. For instance, one may apply ~as by spraying) to the bottom face of the fabric, a latex ~e.g. an acrylic latex such as water-diluted Phoplex HA-8 containing about 5% of the dispersed polymer and some 95% of water), and thereafter subject said bot~om face to a conventional napping operation before (or when) the water has evaporated sufficiently to make the resinous binder sticky; thereafter the napped fabric may be passed through a drier to evaporate the water and set the binder.
; As indicated above, the laminate made from the napped bonded fabric has good skiving and folding characteristics. Skiving generally involves cut- ~-ting with a mechanically operated knife (see Figure 28) in a controlled manner to thin the sheet so that the thinned portion can be folded on itself and held in folded position ~with interposed adhesive) forming an edge of substantially ;~
the same thickness as the main body of the sheet. During the skiving the knife is guided in a direction roughly parallel to the sheet for a substantial por-tion of its travel through the sheet. With the napped bonded laminate of this invention the skiving knife may readily cut through, or pass just below, the interlaced yarn portion of the fabric, leaving at least portions of the inter-laced yarn structure adhered to, and stabilizing, the microporous layer at the thinnest portion of the skived zone ~as in a shoulder scarf, or grooved scarf), permitting formation of a smooth stable, strong fold without the need for in-sertion of an adhered reinforcing tape at the inside of the fold. The napped bonded construction makes it possible to control the skiving and to avoid the *
Trade~ark ' . , :

~08S)598 marked tendency for the direction of the cut to be deflected upwards or down-wards of the plane of the interlaced fabric which occurs when conventional fabrics are used.
While the reasons for the greatly improved skivability of the materi-als of ~his invention are not clearly understood, it is believed that the bond-ing together of the nap fibres act to stabilize and reinforce the fabric struc-ture so that when the knife edge is pressed against the fabric the yarns do not tend to move away, relatively, from the knife edge or be displaced from their previous positions by the pressure of the knife, causing deflection of the direction of the cut. Some bonding of surface portions of the yarns to each other and/or to nap fibres may also contribute to this effect. It is notewor-thy that even where the latter bonding to yarn surfaces takes place, as when a nap-impregnating binder is employed, the presence of the nap tends to prevent substantial filling of the spaces or hollows present at or near yarn intersec-tions ~see Figures 18 and 21) and the structure is not stiffened appreciably, certainly not to the extent that is observed when the same binder is applied to the surface of the same fabric before napping.
Products made from the napped bonded fabric have also been found to be outstanding in their shoe-making characteristics other than the good skiv-ing and folding characteristics discussed above. They attain a very high com-; bined score when rated on their behavior in the following operations of signi-ficance in shoe making; cutting ~with relatively blunt leather dies), stitch-ing, component adhesion ~using conventional latex adhesives, e.g. to adhere stiffeners or "plumpers"), lasting ~conformability), roughening (such as re-sistance to "orange-peel" formation on lasting, and ability to produce a really smooth patent surface), and roughing ~in preparation for sole attachment).
; They are so highly resistant to fraying on wear that they may be used in un-lined shoes without special protection of the cut edges of the material. Fray-ing characteristics may be tested in the following manner: the material is die-cut to form a 3 inch diameter circle or a 2 x 4 inch rectangle and 8 to 16 - 10~30598 such pieces are placed in a smooth surface cylindrical container having an internal volume of one gallon and an internal diameter of 7 7/8 inches (e.g.
a laboratory ball mill of 1 gal. capacity) along with a 5 inch long 2 by 2 inch rectangular piece of pine having rounded edges; the container is then rotated on its axis at 78 rpm for a period of up to 24 hours at room temperature.
Typical samples of the product resist showing any fraying, visible to the naked eye, even after test periods well over 4 hours, such as 12 or 24 hours.
In preferred products the degree of napping is such as to substantially obscure the underlying fabric weave pattern; the fraying test described above may also be used to test the wear-resistance of this effect. Thus, if the nap-bonding treatment is omitted the fabric weave pattern will usually become evident in the foregoing test before the 24 hour test period is over, while the bonded nap will still have its weave-obscuring effect. See Figures 24 (unbonded nap be-fore test), 25 (unbonded nap, after 24 hours test), 26, (bonded nap before test), and 27 (bonded nap after 24 hours test~, which are views looking down onto the nap with an ordinary light microscope, the product being that of Example 20 below; in the same test the product having the bonded nap shows no "pilling"
even though it contains pilling-susceptible polyester fibres, while the product having the unbonded nap shows marked pilling when examined after four hours of test.
It is preferred that the fabric be tightly woven (or tightly knitted) so that there are at least about 3000 yarn cross-overs per square inch (thus the 60 x 60 woven fabric previously described has about 3,600 yarn cross-overs per square inch, while the described 80 x 40 woven fabric has about 3,200 yarn cross-overs per square inch). The thickness of the nap is preferably within the range of a~out 0.1 to 0.5 mm or 1 mm such as about 0.2 to 0.4, O.S, 0.6 or ~ ~
0.7 mm and the weight of fibre in the nap is preferably within the ranges of ~ -about 0.1 or 0;3 to 1 ounce per square yard, such as about 0.2, 0.3 or 0.5 oz.
per square yard. As indicated, each yarn preferably is made up of a pluralityof substantially parallel fibres (generally well over 10, such as 50 or more; the number of fibres can be counted in the illustrated cross sections) and the yarns are preferably twisted, e.g. to well over one turn per inch, such as 2 to 5 turns per inch. Best results have been obtained to date with woven fab-rics in which have at their smooth face repeating, numerous exposed lengths of yarn which span two or more transverse yarns e.g. satin or sateen weaves. It is, howeverJ within the scope of the invention to use square weaves (e.g. sheet-ing), drills or twills.
Napping often increases the number of cross-overs, as by removing portions of weft yarns so that widthwise shrinkage occurs ~see Example 18 be-low, in which the number of cross-overs of the fabric increases by about 10%
as a result of the napping). Preferably the fabric is so constructed that after napping it has a trouser tear strength (ASTM 751-68T) of about 5 pounds, and still more preferably at least about 7 pounds such as 7 to 9 or 10 pounds, and an elongation at break of at least 10% such as 15 to 20% or more. It is also preferable that it have a modulus at 5% elongation (ASTM D-2208) in the range of about 5 to 30 lb/in., that it be sufficiently resilient to recover substantially completely from an elongation, by stretching, of about 2% prefer-ably even from an elongation of about 5% (in the warp or filling direction).
The fabric, particularly when it contains thermoplastic fibres, is preferably given a heat-setting treatment to stabili~e its configuration at the highest temperature to be encountered in the laminating process, e.g. a heat-setting treatment (while the dimensions of the fabric are maintained con-stant, on a tenter frame) at a temperature about 30C above said highest tem-perature, such as a temperature of about 235C for a fabric which is to be vinyl coated in a process using a plastisol-fusing temperature of 205C. This heat-setting may be effected before or, preferably, after napping and may if desired be effected after, or coincident with, the nap-bonding treatment, such as during the curing or setting of the nap-bonding agent. -~
As previously indicated, the fabric may contain such fibres as cot--ton, polyester or nylon. Other fibres such as rayon, acrylic, (e.g. poly-~OB~598 acrylonitrile)~ or polyolefin ~e.g. isotactic polypropylene) and also be em-ployed alone or in blends of two or more type of fibres. Certain fabrics tend to shrink considerably when exposed to elevated temperatures, e.g. 140C (such as are used in some of the Examples, below) for setting the adhesive or the nap bonding agent. With such fabrics, e.g. of polypropylene fibres one can employ known adhesives and bonding agents which are suitable for use at lower temperatures such as those which set quickly to a strong condition on simple evaporation of solvent or diluent, or those which contain sufficient catalyst to cure in a short time at a relatively low temperature; or one can allow a longer time for curing to occur with the particular disclosed agents, e.g. one can pass the assemblage through an oven at a temperature at which the substan-tial shrinkage does not occur (such as 55 or 60 or 70C) to evapoTate any solvent or diluent and then allow full curing to occur on storage for a few days.
The following Examples are given to illustrate the invention further.
In the Examples all pressures are atmospheric unless otherwise indicated. In the application all proportions and percentages are by weight unless otherwise indicated.

A pigmented 15% solution of thermoplastic elastomeric polyurethane ;~
in a solvent mixture of 55%, N,N-dimethylformamide ("DMF") and 45% acetone is deposited ~by knife coating) at a wet thickness of 3 to 4 mils (0.075 - 0.1 mm) - on a sheet of embossed release paper. The polyurethane is of the type described in Example 1 of United States patent 3,637,415 and the amount of pigment ~e.g.
* ~ - .
Superba carbon black) is about 20% of the amount of polyurethane in the solu-~ tion. The deposited layer is exposed to the atmosphere to permit evaporation - of some of the solvent for about 30 seconds, so that it nas a tacky surface, and is then laminated to a self-sustaining thin sheet of microporous elasto-meric polyurethane 0.5 mm thick and specific gravity of about 0.35 g/cm3 (which is soluhle in DMF) by passing the coated release paper and the microporous , *
Trademark ; - 28 -sheet through a nip ~of a steel roll and a rubber-covered roll) with the micro-porous sheet in contact with the coating using light pressure (e.g. about 1 pound per lineal inch of nip~ and applying as little tension as possible to the microporous sheet. The assemblage is then heated in an oven for one minute at 290 - 320F (about 140 - 160C). This removes the solvent and bonds the coat-ing firmly to the paper. The heating may be carried out in two successive ovens, one at 250 - 280F; the second at 290 - 320F. A solvent-containing curable elastomeric adhesive is then applied to the free surface of the micro-porous sheet and a portion of the solvent is allowed to evaporate in the at-mosphere for 1 minute to decrease the flowability of the adhesive and increase its tack. Directly thereafter the adhesive coated material is laminated to a sheet of cotton sateen fabric ~unnapped sateen weighing 250g. per square meter /i.e., 1.21 60-inch yards per poun 7 and having a thickness of about 0.5 mm).
Lamination is effected by passing the material through a nip (of a steel roll and a rubber-covered roll) with the fabric in contact with the adhesive coat-ing, using a pressure (e.g. 3 to 10 pounds per lineal inch) such that the ad-hesive layer is molded into firm adhesive contact with the surfaces of the upper portions of the exposed yarns.
The resulting laminate is then heated in a circulating hot air oven at 280 - 320~ for a time sufficient to substantially remove all the solvent from the adhesive ~e.g. for 1 to 5 minutes), and to partially cure the adhesive.The release paper is then mechanically stripped from the laminate while winding the laminate into roll form with its fabric layer facing outward, and the laminate is allowed to stand in the atmosphere for a time sufficient for the adhesive to cure substantially completely, (e.g., for 72 hours).
The microporous sheet is produced by cutting off the upper layer of ; a two-layer sheet of the type illustrated in United States Patent 3,637,415.
A single layer sheet of the same type may be produced in the manner described in Canadian patent 865,008. The residual salt content of the microporous sheet 3Q is below 0.2%.

- 2~ -108V59~

The curable adhesive is a commercial two-component systeml whose components are mixed just prior to use; the mixture is applied to the micro-porous layer in any suitable manner, as by knife coating at a wet thickness of about 0.1 mm. One component is 100 parts of a 30% solution in a 60% acetone/
40% DMF blend of Impranil C, a hydroxyl-terminated polyester, while the other component is 5 parts of a 75% solution in ethyl acetate of Imprafix TH, a pre-polymer having terminal isocyanate groups (a polyfunctional adduct of toluene diisocyanate and a polyol). When mixed and allowed to cure it forms a cross-linked elastomeric polyurethane; curing may be accelerated by including a catalyst ~such as 1 - 5 parts of Imprafix BE) in the mixture and/or heating.
If the same solvent-containing adhesive is applied to the same micro-porous sheet as such, not bonded to a backing, the sheet swells and distorts extensively.
Details of the Impranil-Imprafix System are given in the article by Glenz and Kassack in Tinctoria Vol. 59 (1962) pages 245 - 249. Another two-component system, of the same type, is a mixture of Witco Chemical's Witcobond 202 and ~itcobond XB.

, Example 1 is repeated except that one face of the microporous sheet is pretreated with water so that (when that face is brought into laminating .
contact with the coated release paper) the microporous sheet carries about 10 - 30% of water (based on the weight of the polyurethane); the release paper is S. D. Warren Company's "Transkote FER" which is a "vinyl paper") and the time in the oven ~directly after the assemblage of coated release paper and wet microporous sheet pass through the nip) is extended (e.g. to 1'~ - 2 minutes) to fully evaporate the water therefrom prior to the application of the adhesive.
The resulting product has a much better water vapor transmission than the product of Example 1. Its WVT is about 27 g/m2/hr. as compared to about 8 - 10 g/m2/hr for the product of Example 1. The WVT of the structure at an .
Trademark losasss intermediate stage prior to the application of the adhesive (i.e. as measured on a structure produced by stripping off the release paper before any adhesive is applied to the free, microporous, side) is about 45 g/m2/hr as compared to 11 - 13 g/m2/hr for the corresponding intermediate structure of Example 1.
The prewetting of the microporous sheet is effected by applying to the upper face of the sheet ~in flat, horizontal condition) water, at a tem-perature of about 40 to 60C ~say 50C) containing about 0.005 - 0.01% of Aerosol OT (a surfactant, sodium salt of dioctyl sulfosuccinate) allowing the water to soak into the sheet for 10 - 30 seconds (e.g. 20 seconds) and squee-geeing off surface moisture directly thereafter.

Examples 1 and 2 are repeated except that after application of the adhesive the assemblage is passed through an oven to remove substantially all solvent (e.g. an oven at 65C). Then the dried adhesive surface is heated ~e.g. with radiant heat) to cause it to soften and become tacky (e.g. at a temperature of about 90 - 120C, such as 110C) The fabric is then immediate-ly brought into contact with the tacky adhesive and the assemblage passed through the nip as described in Examples 1 and 2, Examples 1 and 2 are repeated except that as the adhesive there is employed thermoplastic elastomeric polyurethane (such as Estane 5701) of lower melting point than the polyurethane of the microporous layer, the adhesive be-ing applied as a 25% solution in 50l50 acetone/DMF. The solvent is removed by evaporation and heat is applied to the adhesive layer to raise its temperature above its softening point and make it tacky (e.g. to a temperature of about 135 - 170C) and the fabric is then immediately brought into contact with the tacky adhesive and the assemblage passed through the nip as described in Ex-amples 1 and 2.

Example 1 is repeated using as the release paper S. D. Warren Co.
:

*
Trademark 108059~
Transkote Patent AV:, Hi calf grain~ a polyurethane casting paper. After the adhesive has ~ully cured a two-package clear elastomeric cr~ss-linked poly-urethane coating is applied to the exposed surface of the skin by dip coating or reverse roll coating to produce a high gloss patent leather type of finish.
The amount of coating material applied is such as to produce a clear top coat 15 to 30 microns in thickness on drying and curing. The formulation of the clear coating is a mixture of Permuthane 20-249-100 and Permuthane V5822-70 in 0.7:1 ratio, diluted to 25 - 35% solids with methyl ethyl ketone.

Examples l and 2 are repeated and after the adhesive has fully cured there is applied, to the exposed surface of the skin, a topcoat of an elasto-meric polyurethane having a higher modulus than that of the polyurethane of the skin. The topcoat may be applied by graw re printing a 10 - 15% solution of Permuthane U 10 - 011 in 50/50 toluene/methyl Cellosolve and then heating in an oven at 160C for a short time (e.g. 1 to 1~ minutes) to evaporate the solvent, the coating being applied in such amount as to deposit about 3 to 5 grams of polyurethane per square meter.

Example 1 is repeated, except that the Impranil C is supplied in a solution free of DMF, the solvent being a mixture of 80% acetone (which evapo-rates rapidly) and 20% methyl Cellosolve acetate (which evaporates more slow-ly and is still present in the adhesive layer when the desired tack is attained by evaporation~. Both of these are swelling agents for the microporous layer.

Example 7 is repeated except that the 6.5 ounce per yard ~220 g/m ) fabric havinga lightly impregnated nap, shown in Figure 13 is used in place of the cotton sateen.

Example 7 is repeated except that the unimpregnated napped 8.5 oz.
per square yd. ~290 g/m2) fabric shown in Figure 14 is used in place of the Trademark 108~598 cotton sateen.

Example 7 is repeated except that the napped 8.5 oz. per square yd.
~2~0 g/m ) fabric used in Example 9 is used in place of the cotton sateen.
Thereafter the nap is knife-coated with about lO g (solids basis) per square meter of a two-component solvent-containing polyurethane adhesive blend similar to the adhesive described in Example 7 but employing a softer polyurethane ~specifically a mixtuTe of: 100 parts of a 30% solution, in 80/20 acetone/
methyl cellosolve acetate, of Impranil CHW, a hydroxyl-terminated polyester;

* *
5 parts Imprafix TH; and 5 parts Imprafix BE) and then heatet for 2 minutes at 150 degrees C after which the adhesive layer and nap coating or bonding agent are allowed to cure fully, while the material is at rest, for say 72 hours at room temperature.
The resulting structure is shown in Figures 15 to 17, Figures 15 and 16 are cross-sections, Figure 16 showing a cross-section in a plane at right angles to that of Figure 15; and Figure 17 is view of the bottom (impregnated) face of the fabric. It will be seen that the structure is similar to that shown in Figures 1, 2, 5 - 11 in that there is a layer of woven fabric llA, a layer of microporous elastomeric material 12, an elastomeric adhesive 13 bond-ing the lower face of the microporous layer to the upper face of the fabricand a skin 14 of film-forming polymeric material on the upper face of the micro-porous layer, the adhesive 13 being in contact with the upper surface of the fabric and the fabric being substantially non-impregnated by the adhesive.
Figure 15 shows a warp yarn (running parallel to the plane of the picture) and the cross sections of a total of five weft yarns (running in a direction trans-.~
~ verse to the picture). In Figure 16 a weft yarn runs parallel to the plane of `, the picture and the cross sections of some ten warp yarns are also evident.

; The adhesive deposit is quite thin, like that seen in Figure 1 described earlier, and its character is like that described earlier in connection with Figures 1, 6 and 7. Thus the space between the very uppermost positions of ,~
- Trademark , ~
., .

the warp yarn seen in Figure 15 is largely free of adhesive, and the uppermost portion of weft yarn (seen to the right of Figure 15) makes very little contact with the adhesive layer, there being fingers of adhesive extending down into adhesive contact with said uppermost portion of the weft yarn, probably as a result of the retraction of the layers immediately on release of the laminat-ing pressure and consequent exertion of tension on the adhesive layer to pull adhesive fingers therefrom, leaving open-celled voids between the adhesive on ~
the microporous layer and the top of the fabric and thinning out ~or removing ~ -portions of) the adhesive layer on the microporous layer. ~Figure 16 may give a false impression, at first glance, that there are some individual fibres extending upward into the microporous layer; these fibres are, of course, stray fibres, resulting from the sectioning operation, which happen to have been moved, after seetioning, into positions in front of the plane of the cross-section~
Unlike the structure shown in Figures 1, 2, 5 - 11 the fabric has a substantial low-density nap layer 81 extending down from the interlaced yarn structure; in this case the nap layer has a thickness comparable to that of the interlaced yarn structure. The elastomeric bonding agent or impregnant has, in this case, not penetrated to the interlaced yarns; see the thin webs of impregnant 82 which join and bridge neighbouring fibres but do not form a continuous pore-free layer, there being large impregnant-free spaces 83 between many of the fibres.
EXAMPLES 11 and 12 Examples 8 and 9 are repeated, except that in each case the fabric has 60 warp yarns per inch and 60 weft yarns per inch, the weight of weft yarns being about half of the total weight of the fabric ~before any napping or im-pregna~ion).
EXhMPLE 13 Example 10 is repeated except that the microporous layer is about 0.6 mm thick and the fabric is a sateen fabric (having 60 warp yarns per inch ~08~)598 and 60 weft yarns per inch, each of which is a 73/25 polyester/cotton staple fibre blend, said fabric weighing 8.5 oz/yd2 (200 g/m2) and having been napped so that its thickness in the final impregnated laminate is about 0.75 mm, of which about 0.25 mm is in the nap.
The resulting thicker composite, about 1.4 mm thick, is more suit-able for making lasted men's shoes while the products of the other Examples are more suitable for lasted women's shoes.

The napped 8.5 oz. per square yard (290 g/m2) fabric used in Example 9 is vinyl coated in the following manner. A vinyl plastisol is applied in a thin layer (0.25 mm thick) on vinyl paper and heated to 175 - 180C to form a gelled skin, then a vinyl plastisol containing a blowing agent is cast thereon, at a thickness of 0.53 mm and heated at a temperature of 175 - 180C to gel it and make it tacky, after which the fabric is laid lightly onto the foamable gelled plastisol with the smooth surface of the fabric in contact with said tacky surface and the whole assembly is heated for 1 minute at 205 C to cause blowing (blow ratio 2:1) and fusing. Thereafter the assembly is cooled and stripped from the vinyl paper, and the nap of the fabric is knife-coated as in Example 10.
- 20 The plastisol used for the skin contains 45 parts diisodecyl phtha-late, 10 parts diisodecyl adipate, 100 parts polyvinyl chloride (dispersion -grade, 1 to 3 micron particle size), 10 parts fine calcium carbonate (Duramite ), 3 parts stabilizer ~zinc, cadmium, barium naphthenate), together with about 7%
` (of the total weight of dispersion of pigment in plasticizer).The foamable plastisol contains 28 parts diisodecyl phthalate, 23 parts diisodecyl adipate, 100 parts of polyvinyl chloride, 35 parts of fine * *
calcium carbonate (Duramite ), 1 part of stabilizer (Vanstay 6201), 1.6 part of a mixture of equal parts of a finely divided blowing agent (such as azo dicarbonamide),a liquid plasticizer ~such as dioctyl phthalate and a heat stabilizer which also serves as a blowing activator),and about 4% ~of the total *
-- Trademark 108~598 weight) of dispersion of pigment in plasticizer.

Example 10 is repeated except that in each case the fabric is a sateen fabric having 60 warp yarns per inch and 60 weft yarns per inch, each of the yarns being of a 75/25 blend of polyester/cotton stable fibres, said fabTic weighing 7 ounces per square yard ~240 g/m2), said fabric having been heat set at 240C and napped to bring about 10% of its weight ~about 20% of the weight of the weft yarns~ into the nap.

Example 14 is repeated using the fabric of Example 15. -Example 15 is repeated except that the yarns are of 100% polyester staple fibre.

Example 16 is repeated except that the yarns are of 100% polyester ~ staple fibre.

Example 15 is repeated except that the proportions of cotton and polyester fibre are 50/50 rather than 75/25 and the weight of the fabric is about 8 ounces per square yard ~270 m ).
EXhMPLE 20 Example 16 is repeated except that the proportions of cotton and polyester fibre are 50/50 rather than 75/25 and the weight of the fabric is ` about 8 ounces per square yard (270 g/m2).
The polyester fibre in the foregoing Examples is polyethylene tere-~ phthalate. The fabrics, after napping, ha~e a tongue tear strength ~ASTM D--~i 751-68) of at least about 7 pounds (preferably in the range of about 10 to 15 pounds) in both the warp direction and the weft direction. The grab tensile strength IASTM D-2208-64) of the fabrics is at least about 75 pounds (prefer-ably in the range of about 100 to 150 pounds) in both said directions.

: '',: ' , ' .

iO8~S~8 This assures sufficient strength for the conventional shoe making operations.
EXA~PLE 21 This Example illustrates the effec~ of the napping on the fabric structure and properties. A 4/1 sateen weighing about 6.5 to 7 ounces per square yard and composed of yarns of a blend of 75% polyethylene terephthalate and 25% cotton, with 44 weft yarns per inch and 80 warp yarns per inch, the weft having more fibre than the warp yarns is napped on that face which has a preponderance of weft yarns. As a result of the napping the width of the fab-ric, originally 62 inches, decreases to 57~ inches, the weight per square yard rises to 7.66 ounces, the number of warp yarns per inch rises to 90 while the number of wefts yarns per inch remains at 44. Thus the napping operation, which pulls portions of the filling yarns from the main fabric structure to form the nap, brings the warp yarns closer together and shrinks the fabric about 10%, increasing the crimp of the filling yarns. The napped fabric has the following characteristics (for references, see the Wellington Sears Hand-book of Industrial Textiles by Ernest R. Kaswell, pub. 1963 by Wellington Sears Company, Inc., N.Y., the appropriate pages of that book are given in parenthe-seS below): gauge, thickness 0.026 inch, (pages 571 - 2); contraction, warp 3.88%, weft 10.39% ~page 454); crimp, warp 4.04%, weft 11.60% (page 454); yarn no., warp 19.03/1, weft 7.86/1 ~"indirect" pages 411 - 412, non-metric); grab strength, warp direction 244 pounds, weft direction 196 pounds (ASTM grab, Instron machine having jaws padded with rubberized duck, pages 470 - 471);
elongation at break, warp direction 28.77%, weft direction 41.10% (pages 559 -561); tongue tear strength, warp direction 31 pounds, weft direction 34 pounds .~ *
(Scott J machine, pages 489 - 492); trapezoid tear strength, warp direction 61 pounds, weft direction 47 pounds (Scott J machine, page 493~; bursting strength 367 pounds per square inch (Mullen tester pages 474 - 477).
The fabric of Example 18 is somewhat unbalanced in construction and the unbalance is increased by the napping. It is often preferable to use a - Trademark 108~598 fabric having a more balanced construction, one having about the same numbers of warp and weft yarns per inch, e.g. 80 warp yarns per inch and 80 weft yarns per inch.
Where the fabric is to be exposed to elevated temperature during the process of manufacturing the product (e.g. in the processes of the foregoing Examples 8 - 17) it is preferableJ in accordance with conventional practice, to have the fabric heat-set before using it in the laminating process so as to avoid undesirable heat-shrinkage during the pTocess. For instance the heat-setting may be effected in well known manner to produce a fabric which has little shrinkage, e.g. a shrinkage of less than 2% in the lengthwise (machine) direction and less than 1% in the crosswise direction when subjected ~for, say, 3 minutes) to the highest temperature used in the process.

The napped fabric of Example 21 is heat-set and then vinyl coated as in Example 14. The nap of the resulting vinyl-coated fabric is then knife-~' coated in a manner similar to that described in Example 10, in two passes.
In the first knife-coating pass the fabric travels under tension over rollers and under a coating knife having upstream thereof a bank of the solvent-contain-ing adhesive blend, the coating knife is inclined at an angle to the vertical, the direction of travel being such as to force down the nap to drive the im-pregnant through the nap to the upper surfaces of the yarns comprising the main woven fabric structure. After this first pass under the coating knife the solvent is evaporated by passing the coated fabric through an oven at about 100C for about 2 minutes. It is found that as a result of the impregnation ; in this first pass the weight of the coated fabric has increased from 35.7 oz/yd2 to 36.4 oz/yd2, a net gain of 0.7 oz/yd2, or about 16.6 g/m2 and the thickness of the product ~as measured with an Ames gauge which exerts a com-pacting pressure on the material during the measurement)~has increased from 0.075 inch to 0.083 inch, showing that the nap has increased resistance to compression by virtue of the fibre-bonding action of the impregnant. The ..
In accordance with ASTM D 751-68 second pass is similar except that the blade is disposed in a vertical plane, perpendicular to the fabric, instead of inclined thereto, the conditions beinB
such that the impregnant is not driven down through the nap but remains sub-stantially within the nap. After the solvent has been evaporated in the oven the final curing of the impregnant occurs on standing. The weight of the coat-ed fabric is now 37.7 oz/yd2, a net gain of 1.3 oz/yd2 (or about 57 g/m for the two passes). The final thickness (measured under compression as previously mentioned) is substantially the same as that after the first pass (0.083 inch).
The second impregnation does, however, give improved resistance to pilling of the nap in long term abrasion tests and lays down and bonds loose projecting nap fibres so that the surface is not as soft to the touch and has the appear-ance and feel of conventional impregnated non-woven fabrics used as substrates for commercial artificial leather. The adhesive blend used for the knife coat-ing is a mixture of 37.5 parts Impranil C, 85.5 parts acetone and 27 parts *
methyl Cellosolve acetate, to which is added, just prior to the coating opera-tion, 8.5 parts of Imprafix TRL.
The resulting product is shown in Figures 18, 19 and 20. In Figure 18, which is a view perpendicular to a cross-section cut at right angles to the plane of the fabric, there can be seen the blown layer 91 of vinyl polymer, carrying an unblown skin layer 92, the fabric 93 having an impregnated nap 94, with webs 96 of the impregnant being in contact with both sets of crossing yarns 97, 98. As in Figures 15 to 17 there are thin webs 82 of impregnant which join and bridge neighboring fibres but do not form a continuous pore-free layer, there being large impregnant-free spaces 83 between many of the fibres.
This is also shown in Figure 19 which is a view of the bottom ~impregnated nap) - face of the fabric, taken at an angle of about 45, with an edge cut at right angles to the face visible at the bottom. It will be seen that the nap in Figure 19 carries a considerably greater proportion of impregnant than in Fig-ure 17, but that the structure is still open, having many communicating open-ings which are greater than 0.05 mm across. Another view of the distribution -Trademark _ 39 _ 108~)S98 of the impregnant is found in Figure 20 which is a view showing a cross-section cut about a 30 angle to the skin face of the laminate which cross section is viewed at an angle of about 70 (see Figure 20A). The lower portion of this Figure also shows the bottom (impregnated web) face. Webs 96 of impregnant are seen to be in contact with the crossing yarns, and to bond such yarns.
While this increases the stiffness of the structure somewhat it also increases its resistance to fraying at a cut edge.
Figures 21, 22 and 23 are similar to Figures 18, 19 and 20, respec-tively, except that they are views of a product made by a process in which the blowing and impregnating steps were under less control and in which there was a subsequent embossing step ~the plastisol layers being cast directly onto the fabric instead of the fabric being laid onto plastisol carried by release paper). The resulting product is of a less preferred type, having a heavier deposit of impregnant at the outer surface of the nap and a poorer blown struc-ture. Here, while the webs of impregnant predominate at the surface of the nap (note particularly Figure 22) the outlines of the individual nap fibres are still clearly evident at that surface which still has the texture of those individual fibres, giving it the feel of a fabric surfaceJ and the nap has numerous open spaces ~see Figures 21 and 23) and is thus still readily compres-sible, though much ~ore resistant to compression than the unimpregnated nap.The unimpregnated vinyl-coated fabric used to produce the product of Figures 21 to 23 is about 0.058 inch thick ~measured under some compression as de-scribed above); the first impregnation increases the thickness to about 0.065 inch, while the second impregnation decreases it to 0.062 inch giving a net gain in thickness of 0.004 inch or about 0.1 mm ~as compared to the net gain of 0.2 mm in the product of Figures 18 to 20). The weight gain as a result of the two impregnations is about 2 oz/yd2 ~i.e. about 47 g/m2).
In Figure 18 there is also indicated, schematically, as Figure 28, a circular disc-like skiving knife 101 having a peripheral cutting edge 102, mounted on a rotating shaft 103 and approaching the structure to make a skiv-'' 1C~8V598 ing cut.

This Example employs the napped unimpregnated fabric of Example 21.
The nap of the fabric is then impregnated in two knife-coating passes as in Example 22 to deposit a total of about 1.5 to 2 oz./yd2 of elastomeric im-pregnant after which the unnapped face of the impregnated fabric is then ad-hered to the microporous sheet face of an assemblage of release paper, poly-urethane layer and microporous polyurethane sheet as described in Example 2, using the adhesive described in Example 7.

Example 23 is repeated except that the microporous sheet material has a thickness of about 0.030 inch (about 0.76 mm).
; EXAMPLE 25 In this Example there is employed a 4/1 weft sateen weighing (after napping) 6.6 oz. per sq. yd. and composed of yarns of a blend of 75% poly-ethylene terepthalate and 25% cotton, with about 60 warp yarns per inch and 60 weft yarns per inch, the fahric is heavily napped, the napping elements ` pulling out fibres primarily from the weft yarns and the extent of napping ~as evidenced by the thickness of the resulting nap) being considerably greater than that shown in Figures 12 to 23. The napped fabric is impregnated in two passes by knife coating as in Example 22, but using a softer polyurethane.
O~ing to the thicker nap, having a greater amount of fibre therein, the nap ~; takes up a greater amount of impregnant; the unimpregnated napped fabric has a weight of about 6.6 ounces per square yard, while the nap-impregnated fabric weighs about 9.9 ounces per square yard, so that the weight gain is some 50%
of the original weight. The thickness of the napped fabric ~measured under compression as described above) is 0.026 inch (about 0.65 mm) before impregna-tion and 0.045 inch (about 1.15 mm) thereafter. As in the previously described nap-impregnated fabrics there are thin webs of impregnant which join and bridge neighboring fibres, the outl7nes of the individual nap fibres are still clearly : : .

108~S9B

e~ident the surface which still has the texture of those individual fibres, giving it the feel of a fabric suTface, and the nap has numerous open spaces and is thus still readily compressible, though much more Tesistant to compres-sion than the unimpregnated nap. The opposite, unnapped, face of the impregnat-ed fabric is then adhered to the microporous sheet face of an assemblage of release paper, polyurethane layer and microporous polyurethane sheet as de-scribed in Example 2, using the adhesive described in Example 7. The thickness of the resulting mens-weight shoe upper material is about 1.65 mm. (about 0.065 inch).
The impregnant used in this Example 25 is made by mixing 35.2 parts Impranil CHW, 99.2 parts acetone and 24.8 parts methyl Cellosolve acetate and then, just before use, adding 7.8 parts of a concentrated dispersion of carbon black ~RBH #5485) and 3.85 parts of Imprafix TRL. Impranil CHW is a hydroxy-terminated polyester and Imprafix TRL is a polyfunctional isocyanate;
these react _ situ to form a high molecular weight elastomeric cross-linked polyurethane.
One suitable carbon black dispersion contains 15% of the carbon black, 22.5% of vinyl resin (e.g. vinyl chloride-vinyl acetate copolymer VYHH) and the balance volatile solvents (such as methyl ethyl ketone). Other pigments may be used to impart a uniform coloration to the impregnated napped face.
Example 26 Example 25 is repeated except that the fabric has a weight (after napping) of about 8~ ounces per square yard, being made of thicker, heavier yarns. The thickness of the resulting mens-weight shoe upper material is about 0.07 inch.

Example 23 is repeated using, in place of the cotton-polyester fabric, a fabric of 100% isotactic polypropylene staple fibres weighing about 6~ ounces per square yard and having a count of about 60 warp yarns per inch and 40 weft yarns per inch after napping. In the process the temperatures ~ Trademark 108~598 ~in the ovens used to remove solvent from the impregnated nap and from the adhesive used to join the flat face of the fabric to the microporous sheet) are reduced to about 160F.

Example 23 is repeated except that the microporous sheet material is a two-layer sheet having a thickness of 40 mils ~about 1 mm) and composed of a 15 mil thick upper layer (whose top surface is in contact with the skin3 having a specific gravity of about 0.35 and an integral 25 mil thick more dense lower layer (whose bottom surface is adhered to the fabric) having a specific gravity of about 0.5. A process for producing two-layer products of this type is disclosed in Civardi United States patent 3,637,415.

Example 26 is repeated except that the microporous sheet material is that described in Example 28.
Calculations based on the above mentioned measurements of nap thick-; ness and weight gain on impregnation (in the foregoing Example) indicate that the bulk specific gravity of the impregnant in the nap in the product of Ex-ample 22 is less than about 0.2, e.g. about 0.15. Since the specific gravity of the polyurethane impregnant is on the order of 1.2, it is apparent that the impregnant occupies less than 15% of the volume of the impregnated nap. In the product shown in Figures 21 to 23 the calculated bulk specific gravity of the impregnant in the nap zone is on the order of about 0.5 and the impregnant thus occupies less than half of the volume of the impregnated nap. For the ;~
product shown in Figures 18 to 21 the corresponding Figures are about 0.15 and about 10 - 15%. For the product shown in Figures 15 to 17 the corresponding ~, Figures are about 0.05 (bulk specific gravity) and about 5%. In all these pro-ducts the volume occupied by the fibres themsel~es is very much below 10%, and well below 5%, of the total volume of the impregnated nap; this can be seen from inspection of Figures 18 and 21, particularly by noting the extremely small total area occupied by fibre cross-sections (in the nap zone) in the :

, ~08C~S98 plane in which the sample has been cut. Accordingly it will be apparent that the proportion of voids in the nap zone is generally about 50%, preferably above 70%, such as 80%, 90% or higher.
In the manufacture of shoes, certain protions of the upper material (such as the portions that are formed into the toe of the shoe) are subjected to severe bending with accompanying compression of the underside. The low density impregnated nap is highly compressible. This may contribute to the excellent behavior of the laminate in shoe-making. In addition, in shoe mak-ing the stretching of woven fabric-backed leather substitute materials often causes stressing in a bias direction in which the tensile modulus of the ma-terial is relatively low; that is, the rectangular weave pattern of the fabric is easily distorted into a rhombic or diamond pattern by forces exerted in the bias direction. This can result in wrinkling of the skin layer. In the struc-tures of this invention the bonding by nap-impregnation increases substantially ` the tensile modulus in the bias direction so that the distortion of the weave pattern, and resulting wrinkling, is significantly reduced or eliminated.
The fibres of the nap are usually of a denier per fibre such as is conventionally employed in textile fabrics, e.g. in the range of about 1 to 10 denier, such as about 2 to 4 denier peT fibre. The nap is preferably not a dense one and is preferably unsheared. Typically the number of nap fibres peT
square inch is below 5,000, usually less than 3,000, such as about 1,000 or 2,000; this number may be measured from a photomicrogaph ~such as taken with a scanning electron microscope) by drawing two one inch lines at right angles to each other on the photomicrograph, counting the number of nap fibres which cross each line, and multiplying the sum of those two numbers by the magnifica-tion of the photomicrograph; thus, if on a photomicrograph taken at 60x, a one inch line drawn in the warp direction crosses 10 nap fibres while a one inch line drawn in the weft direction crosses a lesser number, such as 6 nap fibres, the total will be (10+6)x60=960 nap fibres per square inch.

~08~598 It will be noted that in the napped fabrics made by conventional napping tech~
niques (without shearing the nap) the number of nap fibres seen to be crossing the line drawn in the warp will be less than those crossing the line at right angles thereto; also, by unravelling such fabrics one can see that the nap fibres originate primarily from the wefting yarns.
The rotating blades of skiving knives typically are about 3 mm thick, the internal angle at the cutting edge of the blade being, say about 20 . They may be flat disks rotating about an axis normal to the plane of the sheet mate-rial (as in the Amazeen Skiver ) or rotating hollow cylinders rotating about an axis parallel to the plane of the sheet material (as in the Pluma Skiver ).
In the preferred forms of the invention, the bonding of the napped fibres has no substantial effect of the breathability of the product.
A microporous polyurethane sheet material of the type employed in the foregoing Examples was tested for its swelling characteristics in various sol-vents with the following results:

Solvent Initial Wt, after % wt. increase % solvent in Weightswellingon originalwet sample A. Acetone .4438 gm 1.9300 gm 335 77.0 *
B. Ethyl Cellosolve .4350 gm2.2200 gm 410 80.4 Acetate C. Mixture of 4 parts A .4760 gm2.3750 gm 399 80.6 and 1 part B

D. Methylene Chloride .4381 gm3.8500 gm 778 88.6 On a volume basis:

InitialInitialDimensions% volume Dimensions Volume after swelling increase on Solvent cm cc cm cc original A. Acetone 7x4.5x.0440 1.39 8.5x5x.0523 2.22 59.7 B. ~thyl Cellosolve 7x4.5x.04311.36 8.3x5x.0494 2.05 50.7 Acetate C. Mixture of 4 parts 7x4.5x.04531.438.7x4.9x.0541 2.31 61.5 A and 1 part B

D. Methylene Chloride 7x4.5x.04261.349.5x5.5x.0517 2.70 101.5 .

*
Trademark 1o8~598 In the tests, samples of the microporous sheet material are immersed in the solvents for four hours at room temperature and both the weight and volume increases recorded. The samples are checked after a further two hours and show no further increase. After removal of the solvents by drying the samples are all found to regain their original dimensions. .

.

'

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for making a laminate consisting essentially of (a) a layer of permeable fabric made of interlaced fibre yarns and having a flat upper face, the interlaced yarn structure of said fabric having a drape stiffness less than 2-1/4 inches;
(b) a preformed sheet of water vapour permeable microporous elas-tomeric polymer having a density in the range of 0.3 to 0.4 g/cm3 and a thick-ness of 0.3 to 0.8 mm;
(c) an elastomeric adhesive bonding the lower face of said micro-porous layer to the upper face of said fabric, said adhesive being in contact with the upper surface of said fabric, and said fabric being substantially non-impregnated by said adhesive, which comprises adhering one face of a sheet of preformed microporous polymer, which is less than 1 mm thick, to a temporary backer, and adhering the fabric to the other face of the said sheet of preformed microporous material by the application of an adhesive.

2. A process as claimed in claim 1 in which the fabric is adhered to the other face of the said sheet of preformed microporous polymer by applying to the other face of said sheet a thin deposit of an adhesive and, when said adhesive is in tacky condition, pressing thereagainst the fabric to mould said adhesive to the contour of the upper surfaces of exposed yarns of said fabric while keeping the structure of the fabric substantially non-impregnated and non-stiffened by said adhesive and then setting said adhesive and stripping off said backer from said sheet of microporous polymer, said adhesive being one which sets from a tacky condition to a solid non-tacky elastomeric con-dition.

3. A process as claimed in claim 1 or 2 in which the said adhesive is applied to said other face of the sheet of microporous polymer as a solution in a volatile solvent which is a swelling agent for said polymer.

4. A process as claimed in claim 1 in which the laminating pressure is applied momentarily to deform said microporous sheet to force yarns of said fabric, relatively, towards said adhesive deposit and thereby bring their upper portions into contact with said adhesive, said pressure then being released to permit said forced yarns to move away, relatively, with some ad-hesive thereon to form voids in said adhesive.

5. A process as claimed in claim 4 in which the said microporous poly-mer is adhered to the said temporary backer by applying to the said backer a thin layer of a solution of elastomeric polymer in a solvent therefor and applying to said thin layer, while it still contains solvent and prior to solidification thereof, said sheet of microporous polymer, and then removing said solvent from said adhesive layer.

6. A process as claimed in claim 5 in which said sheet of microporous polymer carries a coagulant for said solution in its micropores adjacent to said solvent-containing layer.

7. A process as claimed in claim 6 in which said solvent is a volatile solvent and has an elastomeric polyurethane dissolved therein and said tem-porary backer is "vinyl" release paper, the conditions of the process being such that if said coagulant were to be omitted said structure would not be strippable from said backer without damage to said backer or said microporous sheet.