US 3307961 A
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Filed No'v. 21. 1965 I NVENTORfkann $775431 MHz/5 @55PM/vof@ METHOD PRODUCING AIRA PERMEABLE SHEET MATERIAL 'y Mr'ch v7, 1967 United States Patent() METHOD OF PRQDUCING AIR PERMEABLE SHEET MATERIAL Karl Stiehl and Klaus Oberlnder, Hanau am Main, Germany, assignors to Deutsche Goldund Silber-Scheideanstalt vormais Roessler, Frankfurt am Main, Germany Filed Nov. 21, 1963, Ser. No. 325,433
Claims priority, application Germany, Nov. 21, 1962,
6 Claims. (Cl.v 117-f4) 'The present invention" relates to an improved process for the production of air permeable sheet materials especially suitable as upholstery, coverings, linings and the like.
The usual synthetic leather types, coated ork lacquered textile fabrics, such as woven fabrics, knitted fabrics or fleeces, as well as `foils which have been used for upholstery, coverings or linings are neither air permeable nor permeable to water vapor. In order to prepare air permeable material for the applications indicated it is known, for example, that the synthetic leather or similar materials can be perforated subsequent to their production. It is furthermore known that pierced synthetic leather like material can be produced in that the moving carrier web during application of an elastic synthetic resin layer is perforated by a heated roller which in addition to being provided with engraving depressions is provided with a large number of engraving points. However, both methods have not achievedv wide acceptance. It is especially disadvantageous that the textile carrier is damaged during the perforating or piercing operation. In addition, the -opposing roll, despite the use of special embossing rollers, is subject to strong wear. Furthermore, the limited selection of designs is also of disadvantage. In addition, the perforations give the products an unpleasant noticeably artificial appearance. In addition, when embossing and perforation are carried out as separate operations, it is impossible or very difficult to orient the perforations and the embossed design with respect to each other, especially when complicated designs `are concerned.
A process furthermore is known in which the coating on the fabric is pressed aside all the way down to such fabric in individual locations lwith the aid of especially deep stampings in order to attain a certain porosity. The air permeability thus attained, especially with heavier qualities is only slight and in addition the bond and, under some circumstances, also the fabric are damaged.
The object of the present invention is to provide a simple and inexpensive proc-ess f-or the production of a tear-resistant, flexible, weldable, perforated sheet material which is especially adapted as upholstery, coverings, linings, decoration and the like. The sheet material according to the invention consists essentially of an open or wide meshed fiber structure as a base which is coated on one or both sides with la thermoplastic synthetic resin having spaced openings therein produced by stamping the synthetic resin coating so deeply that at least one side is provided with spaced hollow nob like protrusions and `then grinding or cutting off such protrusions.
ln the production of the coated sheet materials according to the invention, care should be taken that the fabric base is sufficiently open meshed, that is, that a sufficient space is provided between the individual threads of, for example, one to several millimeters. The fabric can, for example, be of :basket weave or netting weave with twist bond. With usual thread strengths of about 20 to 3000 denier, preferably about 1000 to 2G00 denier, a warp and Woof density of about 2 to l2 threads per centimeter, preferably about 5 threads per centimeter, should be em- 3,307,961 Patented Mar. 7, i967 ployed. The threads preferably are multifilament therads and preferably are of synthetic fibers, such as, forexample,vof regenerated cellulose, polyamides, polyesters, such as polyethylene glycol terephthalate, polyacryloni- 5 trile, polycarbonates, or their copolymers, or other polymers customarily employed for the production `of'fib'ers. Fibers of natural origin can also -be employed-for the fabric base. In addition to Woven fabrics, knitted fabrics, or fabric fleeces, which also mustbe of similarvwide lo meshed or open nature, can be employed as the fiber structure serving as the base for the thermoplastic resin coatingor covering. The especially important advantage of such open fiber structures is that only a few if any fibers 4are damaged during the deep stamping operation, so that practically no weakening of the fabric base results. Furthermore, the synthetic resin coating applied to such base increases the strength of the end product without unduly reducing the flexibility of the end product.
The-stamping of the synthetic resin can be effected to produce the nob like protrusions on both sides of the sheet material but preferably on only one side thereof. According to the invention the deep stamping is effected simultaneously with the normal decorative graining or embossing operation with the laid of a suitably contoured embossing roll. Therefore the embossing roll in addition being provided with the usual embossing design is also Yprovided with spaced relatively long spurs and/or relatively deep depressions corresponding in numb-er and shape to the openings which are to be achieved. The length of such spurs or depressions with reference to the usual embossing design being such that when a resilient opposing roll is employed hollow nob like protrusious are respectively either effected in the sheet material on the side opposite to the decorative design or the same side as the decorative design. Such spurs can have any type of cross-section, but preferably are round, oval, angular or star-shaped and press thel resin coated fabric through suiciently far that nob like projections are provided, preferably on the reverse side from the side of the decorative embossed design, which projections can then be ground or cut off without dificulty, f-or example, in a subsequent operation with the aid of knife-, shearingor grinding rolls.
The roll opposing the embossing roll preferably is a rubber roll of not too great a hardness, for example, of a Shore hardness of 60-70".
If the back side of the sheet material is also coated with thermoplastic synthetic resin, such back side can also be embossed :after embossing the front side and cutting off the projections produced on such back side during the first embossing operation.
The embossing of the sheet material according to the invention preferably is carried out at temperatures Within the thermoplastic `range of the resin employed for the coating. Instead of employing the embossing rolls which are preferably employed according to the invention, it is also possible to carry out the embossing discontinuously,
-using embossing stamps.
All known thermoplastic resins or resin mixtures, especially, those containing plasticizers, suitable for the production of coatings and foils can be employed as the coating material according to the invention. Coating masses based on plastisols of polyvinyl halides, such as those produced from vinyl chloride or vinylidene chloride or mixtures thereof, have proved particularly suited, as they permit the production of a material which is especially adapted to be welded.
The sheet materials produced according to the invention are especially adapted for upholstery, covering, decorations, linings and the like, particularly for the automotive industry. They combine good appearance, which can be improved with the use of colored or vari-colored resin coatings, with very good strength and mechanical resistance. The air permeability is very good while permitting hard wear. The type and density of the perforations employed permit wide variations in air permeability.
eter diagonally spaced 6 mm. apart on the coated side against an opposing rubber` roll of a Shore hardness of 60-70". The embossing was carried out at a temperature within the thermoplastic range of the plasticized polyvinyl The air permeability is of special advantage 'when such 5 composition. After the embossed fabric cooled down the material is employed as upholstery material. The sheet hollow nob like protrusions caused by the spurs on the material according to the invention can, however, be emembossing roll were sheared off to leave spaced perforaployed with advantage in the production of shoes and tions (about 350 per dm?) about 1.5 mm. in diameter luggage. Again in such applications the good appearance in the nished embossed sheet. of the sheet material is of special advantage, particularly The material produced had the mechanical properties when the perforations t in well with the embossed deindicated in the following table in which K signifies in the sign which was produced in the same operation as prodirection of the warp and S signifies in the direction of vided for the location and shape of the perforations ultithe Woof. mately obtained in such material.
' TABLE Resistance to Air Permeability, Tensile Strength, Elongatiou on Tear Propagation liters/minute/ICO kg./ 5 cm. break in percent (according to ern.2 at 20 rnm.
DIN 53356) water column pressure K s K s K s 65 sa 24 26 is i7 36o The material can be processed by all of the customary The thickness of such product was 1.1 mm. and its weight procedures, such as, adhesive bonding, sewing or welding. was 850 g./m.2. Of special importance is its capability of being welded to- The use of the open meshed fabric base instead of a gether, not only with itself but also other synthetic leathclose meshed `fabric was in part responsible for the ers or foils and even with ordinary textile upholstery lessened damage to such fabric in the production of the materials, preferably with the aid of high frequency heatperforated product. On the other hand, the spurs on the ing, embossing rolls in producing the nob like projections In the accompanying drawing: which were later sheared oit tended to displace the threads FIG. l diagrammatically discloses an apparatus suitaof the fabric base laterally rather than damage them ble for carrying out the process according to the invenwhenever such threads happened .to be in the path of such tion; and spurs.
FIG. 2 shows a top plan view of a sheet material pro- We claim: duced according to the invention having the openings pro- 1. A method of producing air permeable thermoplastic duced therein oriented with respect to the embossed desheet material reenforced with a liber fabric which comsign.. pris coating at least one side Aof an open meshed ber Referring to the drawing, a we-b 1 of open meshed fabric with a continuous coating of a thermoplastic synnetting is passed through coating tank 2 and the resulting thetic resin, embossing such coating at a temperature coated web 3 is passed through a heated gelling chamber within the thermoplastic range thereof with a decorative 4. The heated gelled c-oated fabric is passed through an design while simultaneously in the same operation emembossing vcalender composed of embossing roll 5 pro- 45 bossing such coating so deeply as to provide spaced holvided with engraved design depressions 6 with spaced low nob like protrusons from at least one side .thereof spurs 6 and opposing vrubber roll 7. The embossed and removing such nob like protrusi-ons to provide spaced coated fabric which now has been provided with hollow openings in such sheet material. nob like projections 8 caused by spurs 6 after cooling 50 2. The method of claim l in which said open meshed is passed through cutter 9 whereby the nob like projecfabric has a thread count in both warp and Woof -of about tions are cut off, leaving perforati-ons 10 in the coated 2 to l2 threads per centimeter, the thread size being befabric. tween 2O `and 3000 denier.
The following example will serve to illustrate the 3. The method of claim 1 in which said open meshed invention. fabric has a .thread count in both warp and woof of about Example 5 threads per centimeter, 4the thread size being between v 1000 and 2000` denier.
A polyester (polyethylene glycol terephtnalate) woven netting having a thread count lof 5 muitilament threads t 4'. Tige plocess of dam 1 m Whfch the DOP h ke pro' of 1000 denier in -b-oth warp and woot was placed over a 2151021, ,Caused by the dfep embssmg momma .bpm the polyvinyl chloride sheet 0.2 mm. thick which had been lmooss neaiOpposite to that rewmg the produced from a plastisol of the following composition. 5. The process of Claim 4 in which Said prorusions Percent by Weight and the openings resulting therefrom are oriented with Polyvinyl chloride (emulsion polymer of a K value respect to the decgrative designv Of abOllt 75) 50 6. The process of claim 1 in which said coating is of Dioctylphthaiate 40 65 piasricized poiyvinyi chioride. Paraflin v0.31 Pigment Vand filler (titanium dioxide) 8.94 References Cited by the Examiner Dlblltyl till maietllle CL75 UNITED STATES PATENTS Thereafter the upper side of the associated netting and 2,817,595 12/1957 schuf 117 4 sheet was coated twice with a piastisol of the same com- 2,861,006 11 /1958 53,11111 117%11 X position so as to apply a total coating of 30G-400 g./m.2. 3,137,393 6/1954 Gdpke 117 4 X The composite structure was then heated and calendered. 3,214,502 10/1955 Schaar 117 4 X v Subsequently the material was embossed with an ernbossing roll provided with spurs about 1.5 mm. in diam- MURRAY KATZ, Primary Examinez'.