US3723161A

US3723161A - Process and apparatus for the production of synthetic leather

Info

Publication number: US3723161A
Application number: US00059877A
Authority: US
Inventors: H Fleissner
Original assignee: Vepa AG
Current assignee: Vepa AG
Priority date: 1969-07-31
Filing date: 1970-07-31
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27
Also published as: DE1940954B2; DE1940954C3; DE2009662A1; FR2054661B2; CH552703A; CH1114570A4; DE1940954A1; GB1312969A; DE1938966A1; FR2054661A2

Abstract

An apparatus and method for producing synthetic leather comprising the manipulative steps of impregnating, drying and coagulating, shrinking, washing and finally drying a fiberous web.

Description

o A United States Patent 1 1 1 1 3,723,161 Fleissner Y 1 1 Mar. 27, 1973 1 PROCESS AND APPARATUS FOR THE 1 kflelellces 1 PRODUCTION OF SYNTHETIC UNITED STATES PATENTS LEATHER 602,797 4/1898 Annison ..1 17/ 10 [75] Inventor: Heinz Flelssner, Egelsbach, Ger- 2,197,147 4/1940 Hadley ..26/18.5 many 2,588,624 3/1952 Evans ..26/18.5 Q 3,102,006 8/1963 Cohn et al.. ....26/18.5 X [73] Assgnee' 3 Baseuschwe'z sw'tzer 3,255,064 6/1966 Makansi ....28/72 NW i 7 3,272,898 9/1966 Knee ..28/72 NW [22] F1166: JiTy 3T, 197T 3,460,898 8/1969 Fleissner ..68/D1G. s 3,994,819 2/1970 McAlister ..161/150 X [2]] App! 59877 3,529,447 9/1970 Fleissner et a1 ..28/18.5

'30" F n A 11 6116161661 Bath 1 l 1 pp c n y Primary Examiner-Edward G. Whitby July 31, 1969 Germany ..P 19 38 966.3 yg, o e i & i l Aug. 12, 1969 Germany ..P 19 40 954.2 Nov. 5, 1969 Germany ..P 19 55 653.7 7 ABSTRACT Mar. 2, 1970- Germany..- ..P 20 09 662.2

I An apparatus and method for producing synthetic U.S. CL "1.17/66, NW, leather comprising the manipulative steps of im- 68/DIG' 1 17/10 pregnating, drying and coagulating, shrinking, washing 1 17/1355, l17/138.8 R, 117M383 N, and finany drying a fiberous b 117/141,117/144,118/50,156/84,156/209, 156/219,161/150, 161/170 [51] Int. Cl. "B4411 1/092 [58] Field 61 Search ..68/D1G. 5; 26/185; 117/10, 2 1

PATENTEDmzTms SHEET 10F 2 Jnveniow HEINZ FLE\SSNER BY Graig, Qfltonelli, Stewart W ATTORNEYS PROCESS AND APPARATUS FOR THE PRODUCTION OF SYNTHETIC LEATHER BACKGROUND OF THE INVENTION particularly for the production of synthetic leather, i.e. 0

material lengths which serve as a carrier fabric onto which a surface coating is spread, adhesively applied, or the like. In the present process, the filling or: bonding agents are applied to the textile material lengths in the form of aqueous solutions or dispersions and the filling or bonding agents used are usually a thermosensibilized product such as a synthetic latex. The textile material length onto which the bonding agent is applied is subsequently heated-up, contact-free to a temperature at which the bonding agent coagulates, mechanically dehydrated by means of squeezing units or suction devices, and finally dried. The bonding agent is cured or vulcanized.

If knit cloths or fabrics are used as carriers for synthetic leather, they are usually coated with a plastic material. It has been previously suggested to pour the coating mass on or to apply it in the form of a thin foil.

It is also possible to harden the surface of the carrier fabric first by spreading a bonding agent thereon. However, the synthetic leather thus produced tends to break easily and has a low flexing capacity. These properties essentially depend on the type of carrier utilized.

SUMMARY OFTHE INVENTION An object of the present invention is to provide a means for producing a synthetic or artificial leather which has the same properties as real leather and can be manufactured in a simple, quick and economical way.

Another object of the present invention is to simplify the production line by eliminated certain machine units in the production of the synthetic leather.

Still another object of the present invention is to provide a means for carefully handling material lengths which are difficult to emboss or which require a very sharply-designed pattern.

A further object of the present invention is to simultaneously effect the coagulation of the bonding agent and the shrinking of the web of textile material.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

According to the present invention it has been found that bonding the carrier cloth or fabric helps to iniprove the flexibility of this kind of material substantially and also cut down its tendency to break. It is therefore suggested, in accordance with the present invention, to use a material which consists of highlyshrinkable fibers which has been subjected to a shrinking process. By means of the shrinking process, a very dense carrier fabric is produced which possesses all of the required properties and which is sufficiently strong. The shrinking fibers used can be polyester for example, polyethylene terephthalate or polyamide fibers, for example, polyhexamethylene adipamide, and it is also possible to use polypropylene fibers which shrink considerably when being subjected to a thermal process. It is also suggested, in accordance with the present invention, to add a certain amount of melting fibers to the shrinking fibers. By making these fibers melt, the bonding effect is improved and a better elasticity of the fabric is obtained. The melting fibers can be, for example, polypropylene or some other similar type fiber.

The carrier cloth or fabric can for instance consist of approximately 20 to 50 percent shrinking fibers and approximately ID to 15 percent melting fibers. According to the present invention the remaining fibers can be those which are won from natural substances, such as rayon staple fibers. It is advantageous to add a certain amount of natural fibers because they improve the water absorption capacity of the synthetic leater and the similarity of synthetic leather to natural leather is thus increased.

As the intimate connection of the surface coating and the carrier fabric is usually obtained by means of a heating process in which the components of the carrier fabric, according to the present invention, are subjected to uncontrollable changes, it has been found advantageous to shrink the carrier cloth or fabric before the coating mass is applied and to subsequently spread the coating on or apply it in some other way. Shrinking is effected by means of heat. If polyamide or polyester shrinking fibers are used, it is expedient to heat the carrier fabric in a water containing bowl to about to C., at which temperature the shrinking process will take place. If polypropylene shrinking fibers are used, shrinking is effected by means of hot air or superheated steam. In case polyamide or polyester fibers are to be melted in one operation with polypropylene fibers, it is advisable to do this at a temperature of l60 to C., which is the melting temperature of polypropylene. Trials have shown that processing temperatures may range between 150 and C.

Apart from having about the same properties as natural leather, synthetic leather must also have a similar appearance; its surface must therefore be provided with a grain-like pattern. This embossing process is rather expensive, especially because costly calenders are needed. According to the present invention it has been found that the embossing process becomes unnecessary if shrinking is effected after the coating mass has been applied. When the carrier fabric shrinks the surface automatically forms wrinkles because the coating itself does not shrink. This is a very simple way indeed of obtaining a leather-grain imitation.

However, in accordance with the present invention, synthetic leather production can be simplified still further. For heating the shrunk, dried and impregnated material length up to the point of coagulation of the coating mass, i.e. to about 40 to 50C., it has been suggested by the prior art to guide the material, contactfree, through a drying duct. When the bonding agent has coagulated, the material is washed so that the thermosensibilized and other additives are removed. The

web is thus rendered more air-permeable and its breathing activity is improved. After this washing process the material is finally dried.

The above described process for producing the basic material of synthetic leather is rather time-consuming and the required machines are rather expensive. Therefore, it is another feature of the present invention to simplify the production of the basic material so that certain machine units can be eliminated. This simplification is achieved by changing the conventional process in the manner that an unshrunk carrier web, cloth or fabric is impregnated with the bonding agent and only thereafter subjected to the shrinking process. This sequence of processing steps entails not only a shortening of the whole process, because the intermediate drying process after shrinkage is unnecessary, but also the obtainment of a denser final product because the unshrunk material absorbs a greater amount of bonding agent than a pre-shrunk one.

In accordance with the present invention it is also suggested to transform the bonding agent chemically, i.e. to heat it up to its coagulation point before the shrinking process sets in. This heat treatment as such has been suggested previously but up to now it was always carried out with the web being already shrunk.

Still another feature of the present invention which is even more advantageous and even more cost-saving is when coagulation of the bonding agent and shrinking of the web is effected simultaneously, in a hot shrinking bowl. The unshrunk web which is already soaked with the bonding agent liquor is fed into the shrinking bowl where the bonding agent coagulates under the influence of heat and the web shrinks at the same time. With this process it is inevitable that a certain amount of the bonding agent will cling to the conveying elements of the apparatus. However, this is not too great a disadvantage because the simple guide rollers can be easily cleaned each time the bonding agents are changed. The carrier fabric is then provided with a coating and a leather-grain surface structure.

The conventional embossing units consist of solid rollers or rollers with very thick jackets which are usually made of steel. The roller jackets are provided with the embossing pattern. The material passes the embossing unit with the side which is to be embossed lying on the surface of the embossing roller and is pressed against this embossing roller by another roller. lt is a known method to produce the embossing pattern either by a cold molding process or by embossing the plastic coating mass which is subsequently hardened. Equally well-known is the method of dehydrating paper and textile material lengths by means of providing at least the bottom roller with a liquid-permeable jacket and possibly by designing this bottom roller as a suction roller. The squeezed or drawn-off liquor can be removed through the pores or holes of the roller. It is also known to guide the material on the suction roller by means of an adjoined perforated belt so that it is held and conveyed between the roller and this belt during the dehydration process.

lt is a further feature of the present invention to provide a means for careful handling material lengths which are difficult to emboss or which require a very sharply-designed pattern. According to the present invention this task is solved in an effective way by pressing the material against an air-permeable embossing roller by means of a suction draft or a vacuum created in the roller. In this case the material is not only tangent to the embossing roller, as in the conventional embossing processes, but adheres to it for a certain time because of the suction draft. To obtain this intimate contact of the material with the roller it is advantageous to press the material length at least at the inlet point against the embossing roller by means of another roller. The embossing pattern is thus produced by mechanical pressure and the intimate contact of material and roller safeguarded by the suction draft. Making use of the suction draft is especially advantageous with material lengths which are air-permeable even after having been coated and embossed, e.g. with synthetic leather.

It makes no difference whether the coating is applied in the form of a thick foil, whether it is spread on or whether it is produced by means of a precipitation process in a treatment bowl. With very elastic material lengths or material lengths which are difficult to emboss it can be advantageous to guide the material length between a tensioned perforated belt and the embossing roller which is subject to a suction draft so that the material is pressed against the roller by the perforated belt. If the coating is air-permeable it is desirable to draw air, steam or a liquid through the material length during the embossing process. This improves the air-permeability of the material and also, with a polyvinyl chloride coating, for example, it is possible to cool the material and the still plastic coating mass by means of fresh air and thus harden the polyvinyl chloride coating. Besides, the embossing roller itself can be cooled so that in addition, contact cooling of the material is possible.

With cold or insufficiently heated material lengths it is possible to render the coating plastic, and as a consequence to improve the embossing effect, by heating the embossing roller or by drawing a heated treatment medium such as hot air or steam through the roller and the material.

lf, for example, the molecules of an already applied polyurethane coating are to be cross-linked in a liquid, it is possible to make the material air-permeable by arranging the embossing roller in the liquid and drawing the liquid through the material length. This liquid can be a 60 percent DMF solution. Generally, it can be said that, if the coating is not too thick, the air-permeability is produced or at least improved by means of the suction draft.

It is expedient to design the embossing roller as a hollow body and to use an airor liquid-permeable construction material such as sintering metal, fibrous metal or the like or else to provide it with small boreholes in order to make it air-permeable. This embossing roller is then provided with the embossing pattern, e.g. with an engraving. The embossing unit comprising such an airpermeable embossing roller must also be equipped with an essentially well-known fan or pump assembly for producing the suction draft or vacuum inside the embossing roller.

In general, these embossing rollers, just as with the known suction drums or suction rollers, can be equipped with baffle plates which are arranged inside or outside of the roller, at that roller section which is not covered by the material length being treated. The baffle plates screen this section from the suction draft. Guide rollers are adjoined to the embossing roller, the suitable arrangement of which ensures the required looping of the material length around the embossing roller. Here it is advantageous if at least one, and preferably the first of these guide rollers is equipped with a pressure device which presses the guide roller against the embossing roller or against the material length adhering to the roller surface. It has already been mentioned that, depending on the type of coating used, it is expedient to heat or cool the embossing roller.

Apart from simplifying the embossing unit at the end of the apparatus, it is also possible, according to the present invention, to simplify the apparatus length as such. The apparatus of the present invention consists of the following individual machines:

a. a padder for applying the bonding agent,

b. a liquid bowl for shrinking the web and for the chemical transformation of the bonding agent,

c. a washing machine with preferably at least one perforated wash bowl which operates on the autoflow principle, and

d. a dryer, preferably a perforated drum dryer.

A drying duct can be arranged in front of the liquid bowl (see item b above). This duct, through which the fiber web is guided contact-free, ensures the coagulation of the bonding agent which has been applied in the padder.

While the textile material length which has been provided with about 200 to 300 percent (b.d.w.) bonding agent is guided contactfree through the vertically arranged drying duct in which it is heated up to the coagulation point of the agent and subjected to a hotair stream or exposed to radiation, the bonding agent will coagulate rapidly before being able to migrate, and also at least a part of the material surface which is first heated up will also dry out. However, any drying-out of the material will produce migration of the bonding agent, which must by all means by avoided. It has been suggested to apply a heated gas such as air or superheated steam to the material, apart from treating the material by means of infra-red radiation and/or by means of spraying nozzles. The use of steam is advantageous because it condenses on the cooler material and the thus created condensate effects a rapid heating-up of the material. However, it is also disadvantageous insofar as the moisture content of the material is increased and a longer drying process becomes necessary. This drawback can be eliminated by providing spray nozzles which are arranged in the duct in front of the heating batteries (when viewed in the direction of material passage) and which apply steam to the material length. These spray nozzles ensure that right at the beginning of the process, the material is covered by a water film at a temperature of about l00C., which water film causes the bonding agent to coagulate and also heats the upper material surface only. When the material subsequently passes the heating batteries, the evaporation water film eliminates any drying-out of the material surface while still ensuring the heating up of the entire material layer to the required temperature. When the material then reaches the discharge end of the drying duct, it is thoroughly heated up to the coagulation temperature of the bonding agent but has not absorbed any superfluous amount of moisture.

The padder can be of any desired design. However, it is advantageous to use a padder which contains a submerged squeezing unit for removing the air from the unshrunk fiber web, thus improving the liquor absorbing capacity of the material. It is further advantageous to arrange a material scray in front of the padder in order to ensure the uninterrupted material supply to the padder even in the case where the preceding batching unit has been completely emptied. The material scray is preferably equipped with a pair of driven draw-off rollers which guide the unshrunk and therefore very delicate web without any tension into the material scray. The batching unit, too, should be driven to ensure the absolutely tension-free transportation of the material.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by wayof illustration only and thus are not limitative of the present invention and wherein,

FIG. I shows a device comprising a pre-drying duct for treating the basic material of synthetic leather;

FIG. 2 shows a device according to FIG. 1, however, without a drying duct;

FIG. 3 is a cross section of a perforated embossing roller which is subject to a suction draft; and

FIG. 4 is a longitudinal section of the roller according to FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS From a driven batching unit 1 (see FIG. 1), an unshrunk fiber web 2 is guided to an equally driven pair of rollers 3 which are arranged at the upper end of a subsequent material scray 4. The fiber web is plaited into the material scray so that it is unnecessary to stop the entire treatment line in order to provide an emptied batching device 1 with a new batch of material.

From the material scray, the unshrunk fiber web 2 is fed into a subsequent padder 5 which is filled with a bonding agent, such as a thermosensibilized latex or a thermosensibilized polyurethane dispersion. At the inlet end of the padder 5 there is provided a guide roller 6 and a pressure roller 7, the latter of which removes the air from the material. It is advantageous to feed an unshrunk web into the padder because such a web features a better absorbing capacity than a shrunk web. A denser and more stable final web is thus produced.

From the padder 5, the web is led upwards, contactfree through a drying duct 8 (only schematically shown in the drawing). In this duct, the material is heated up to about 40 to 50C., at which temperature the bonding agent coagulates. The fiber web which is overfed in width by pleating rollers 10 and overfed in length by a pair of feed rollers 11 which follow a compensating section 12, is then heated up, shock-like, in a bowl. In this process, the web shrinks in both width and length.

After the shrinking process, the basic material for the production of synthetic leather needs only to be washed in a washing machine 13 and dried in a dryer 14. It can be washed either in a perforated drum wash bowl 15, operating on the autoflow principle or in a washing machine which comprises several pairs of squeeze rollers 16 and an intermediate washing agent spraying unit 17. Also both the wash bowl and washing machine can be utilized.

FIG. 2 shows a device which is very similar to that shown in FIG. 1, the difference being that the predrying duct is not utilized. in this case it is preferable to add coagulating auxiliaries such as ammonium salts to the liquor in the shrinking bowl 9. This ensures the complete coagulation of the bonding agent which has previously been applied in the padder while the web shrinks at the same time.

At the end of the device shown in FIG. 1, i.e. following the perforated drum dryer 14, there can be installed either a winding unit for winding up the material length 2 or an embossing unit for the production of a leathergrain pattern on the material surface. FIGS. 3 and 4 show an embosiment of this embossing unit.

The material length 2 is guided over a roller 20 to an embossing roller 21. As suggested by the arrow 22, the roller 20 serves as a pressure roller which presses the material length 2 against the embossing roller 21. This embossing roller 21 is subject to a suction draft which draws the material length tightly onto the surface of roller 21. The section of the embossing roller which is not covered by the material length is screened off from the suction draft by a stationary baffle plate 23. Another roller 24 serves as an outlet roller.

FIG. 4 shows that a fan 25 is adjoined to the embossing roller 21, at one of the roller front sides, said fan producing a high negative pressure or suction draft of, for example, 100 mm. water gauge, within the embossing roller. The baffle plate 23 is fitted to a stationary axis 26 on which also the embossing roller 21 is supported. The embossing roller can be connected with a drive assembly (not shown) by means of a hollow shaft 27.

Any of the natural and synthetic fibers which are well known in the manufacture of synthetic leather can be used in the present method. The natural fibers may in-. clude, for example, cotton, wool, cellulose, regenerated cellulose, etc., and the synthetic fibers may comprise polyamides, e.g. nylon which is the reaction product of adipic acid and hexamethylenediamine, polyolefins, e.g., polypropylene, etc., polyesters e.g., dacron which is made from methyl terephthalate and ethylene glycol, vinyl polymers, e.g., polymethyl methacrylate, rayon and similar materials. The method and apparatus of the present invention is also applicable to blends of the above-mentioned textile materials.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be apparent to one skilled in the art are intended to be included.

What is claimed is:

l. A method for the production of a textile material length made of knit cloths or fabrics containing filling or bonding agents for use in the production of synthetic leather which comprises the steps of impregnating an unshrunk fiber web containing highly shrinkable synthetic fibers with a coagulatable bonding agent,

conveying said web contact-free through a drying zone where the web is heated to a temperature sufficient to coagulate the bonding agent, overfeeding said web in both its length and its width to a shrinking zone wherein the web is heated, shock-like, to a temperature sufficient to shrink the web in both its length and its width and to provide a very dense carrier fabric web, washing the dense web and finally drying said dense web by drawing a heated drying medium therethrough.

2. A method for the production of a textile material length made of knit cloths or fabric containing filling or bonding agents for use in the production of synthetic leather which comprises the steps of impregnating an unshrunk fiber web containing highly shrinkable synthetic fibers with a coagulatable bonding agent, overfeeding said web in both its length and its width to a shrinking and coagulating zone where said web is heated, shock-like, to a temperature sufficient to shrink the web in both its length and its width and to provide a very dense carrier fabric and at the same time to coagulate the bonding agent, washing the dense web and finally drying said dense web by drawing a heating drying medium therethrough.

3. The method of claim 1, wherein the surface of the finally dried dense web is embossed by conveying the dense web over an embossing surface, the dense web being held to said surface by a suction draft which is drawn through the dense web.

4. The method of claim 2, wherein the surface of the finally dried dense web is embossed by conveying the dense web over an embossing surface, the dense web being held to said surface by a suction draft which is drawn through the dense web.

5. The method of claim 3, wherein the dense web is additionally pressed against the embossing surface at at least the point of introduction of the dense web to said surface, by contact pressure.

6. The method of claim 4, wherein the dense web is additionally pressed against the embossing surface at at least the point of introduction of the dense web to said surface, by contact pressure.

7. The method of claim 3, wherein the dense web is additionally pressed against the embossing surface by a tensioned perforated belt which is complimentary to said embossing surface.

8. The method of claim 4, wherein the dense web is additionally pressed against the embossing surface by a tensioned perforated belt which is complimentary to said embossing surface.

9. The method of claim 3, wherein air, steam or a liquid is drawn through the dense web by said suction draft during the embossing step.

10. The method of claim 4, wherein air, steam or a liquid is drawn through the dense web by said suction draft during the embossing step.

11. The method of claim 1, wherein the unshrunk fiber web contains a mixture of synthetic melting fibers and the synthetic shrinking fibers.

12. The method of claim 1, wherein the unshrunk fiber web contains about 20 to percent of the synthetic shrinking fibers, and about 10 to 15 percent synthetic melting fibers, the substantial balance being natural fibers.

13. The method of claim 2, wherein the unshrunk fiber web contains a mixture of synthetic melting fibers and the synthetic shrinking fibers.

14. The method of claim 2, wherein the unshrunk fiber web contains about 20 to 50 percent of the synthetic shrinking fibers, and about 10 to percent synthetic melting fibers, the substantial balance being natural fibers.

15. The method of claim 3, wherein the fiber web is coated with a surface coating after said web has been shrunk. I

16. The method of claim 1, wherein the fiber web is coated with a surface coating prior to shrinking said web, thereby producing a leather-grain pattern in said coating during the shrinking step.

17. A method for the production of a textile material length made of knit cloths or fabrics containing filling or bonding agents for use in the production of synthetic leather which comprises the steps of impregnating an unshrunk fiber web with a bonding agent, conveying said web contact-free through a drying zone where said web is heated to a temperature sufficient to coagulate the bonding agent, overfeeding said web in both its length and its width to a shrinking zone wherein the web is heated, shock-like, to a temperature sufficient to shrink the web in both its length and its width, washing the web, drying said web by drawing a heated drying medium therethrough and thereafter embossing the web by conveying the web over an embossing surface,

said web being held to said surface by a suction draft which is drawn through the web and a coating being applied to the web during the embossing step.

18. A method for the production ofa textile material length made of knit cloths or fabrics containing filling or bonding agents for use in the production of synthetic leather which comprises the steps of impregnating an unshrunk fiber web with a bonding agent, overfeeding said web in both its length and its width to a shrinking and coagulating zone where the web is heated, shocklike, to a temperature sufficient to shrink the web in both its length and its width and at the same time to coagulate the bonding agent, washing the web, drying said web by drawing a heated drying medium therethrough, and embossing the web by conveying the web over an embossing surface, said web being held to said surface by a suction draft which is drawn through the web and a coating being applied to the web during the embossing step.

19. The method of claim 17, wherein the coated web is provided with an embossed surface.

20. The method of claim 18, wherein the coated web is provided with an embossed surface.

Claims

2. A method for the production of a textile material length made of knit cloths or fabric containing filling or bonding agents for use in the production of synthetic leather which comprises the steps of impregnating an unshrunk fiber web containing highly shrinkable synthetic fibers with a coagulatable bonding agent, overfeeding said web in both its length and its width to a shrinking and coagulating zone where said web is heated, shock-like, to a temperature sufficient to shrink the web in both its length and its width and to provide a very dense carrier fabric and at the same time to coagulate the bonding agent, washing the dense web and finally drying said dense web by drawing a heating drying medium therethrough.
3. The method of claim 1, wherein the surface of the finally dried dense web is embossed by conveying the dense web over an embossing surface, the dense web being held to said surface by a suction draft which is drawn through the dense web.
4. The method of claim 2, wherein the surface of the finally dried dense web is embossed by conveying the dense web over an embossing surface, the dense web being held to said surface by a suction draft which is drawn through the dense web.
5. The method of claim 3, wherein the dense web is additionally pressed against the embossing surface at at least the point of introduction of the dense web to said surface, by contact pressure.
6. The method of claim 4, wherein the dense web is additionally pressed against the embossing surface at at least the point of introduction of the dense web to said surface, by contact pressure.
7. The method of claim 3, wherein the dense web is additionally pressed against the embossing surface by a tensioned perforated belt which is complimentary to said embossing surface.
8. The method of claim 4, wherein the dense web is additionally pressed against the embossing surface by a tensioned perforated belt which is complimentary to said embossing surface.
9. The method of claim 3, wherein air, steam or a liquid is drawn through the dense web by said suction draft during the embossing step.
10. The method of claim 4, wherein air, steam or a liquid is drawn through the dense web by said suction draft during the embossing step.
11. The method of claim 1, wherein the unshrunk fiber web contains a mixture of synthetic melting fibers and the synthetic shrinking fibers.
12. The method of claim 1, wherein the unshrunk fiber web contains about 20 to 50 percent of the synthetic shrinking fibers, and about 10 to 15 percent synthetic melting fibers, the substantial balance being natural fibers.
13. The method of claim 2, wherein the unshrunk fiber web contains a mixture of synthetic melting fibers and the synthetic shrinking fibers.
14. The method of claim 2, wherein the unshrunk fiber web contains aboUt 20 to 50 percent of the synthetic shrinking fibers, and about 10 to 15 percent synthetic melting fibers, the substantial balance being natural fibers.
15. The method of claim 3, wherein the fiber web is coated with a surface coating after said web has been shrunk.
16. The method of claim 1, wherein the fiber web is coated with a surface coating prior to shrinking said web, thereby producing a leather-grain pattern in said coating during the shrinking step.
17. A method for the production of a textile material length made of knit cloths or fabrics containing filling or bonding agents for use in the production of synthetic leather which comprises the steps of impregnating an unshrunk fiber web with a bonding agent, conveying said web contact-free through a drying zone where said web is heated to a temperature sufficient to coagulate the bonding agent, overfeeding said web in both its length and its width to a shrinking zone wherein the web is heated, shock-like, to a temperature sufficient to shrink the web in both its length and its width, washing the web, drying said web by drawing a heated drying medium therethrough and thereafter embossing the web by conveying the web over an embossing surface, said web being held to said surface by a suction draft which is drawn through the web and a coating being applied to the web during the embossing step.
18. A method for the production of a textile material length made of knit cloths or fabrics containing filling or bonding agents for use in the production of synthetic leather which comprises the steps of impregnating an unshrunk fiber web with a bonding agent, overfeeding said web in both its length and its width to a shrinking and coagulating zone where the web is heated, shock-like, to a temperature sufficient to shrink the web in both its length and its width and at the same time to coagulate the bonding agent, washing the web, drying said web by drawing a heated drying medium therethrough, and embossing the web by conveying the web over an embossing surface, said web being held to said surface by a suction draft which is drawn through the web and a coating being applied to the web during the embossing step.
19. The method of claim 17, wherein the coated web is provided with an embossed surface.
20. The method of claim 18, wherein the coated web is provided with an embossed surface.