DE920211C - Process for the production of porous fiber-containing surface structures - Google Patents

Description

Process for the production of porous fibrous sheet-like structures Es is already a process for impregnating loose, unspun, coherent Known fiber masses with low viscosity, aqueous rubber dispersions, in which the both surfaces of the pile-like sliver by dusting a small amount an adhesive with the release of passages for the impregnating liquid solidified, the structure thus pretreated horizontally next to each other through the gap out of stored rollers and here the impregnation liquid, z. B. rubber milk, is pressed into the fiber layer from both sides in such a way that it extends to in the core is wetted, the introduced impregnation liquid by heating and Drying the structure is solidified and these are calendered. This for that Manufacture of leather substitutes requires certain processes to be practical for implementation the rubber content required for this a multi-stage impregnation with the liquid dispersion, each with subsequent drying and calendering. at the first impregnation creates a structure that has a large number of cavities which is filled in during the second and, if applicable, the third impregnation will.

The known method has various disadvantages, which are overcome in accordance with the present invention. The use of liquid impregnating agents offers, among other things, the so-called floating of the fleece in the Liquid, for sticking the structure to the apparatus during further processing and squeezing off excess impregnation liquid after each impregnation. the solidified by pretreating the two surfaces of the fiber layer with adhesives Surface layers are still permeable, smooth, uniform and complete However, thorough impregnation is only possible with the use of highly diluted impregnation liquids, z. B. an aqueous rubber dispersion which is not more than about 6 to 12% Contains solids. This necessitates a multi-stage implementation of the impregnation process with the interposition of drying and calendering processes and thus the inevitable introduction of large amounts of water, their removal by Drying requires a considerable amount of heat. Because of the multitude of these treatments the relatively thin fiber structures are subjected to heavy loads, which have the effect, among other things, that the fleece is an alignment of the Fibers in the longitudinal direction, which increases the resilience of the finished products, especially with regard to tensile strength in the transverse direction, tear resistance and elongation in the longitudinal direction, is adversely affected. When using Impregnation liquids, which contain additives such as vulcanizing agents, anti-aging agents, If they contain finishing agents, fillers and the like, further difficulties arise. In the thin fluid medium, the fillers etc. settle easily, so that uneven Distribution in the mixture and frequent sludge formation occurs. Also have the substances present in solid form in the liquid impregnation liquid Tendency to prematurely build up on the fibers, especially in those that have been condensed by pretreatment, surface layers acting as a filter, so to speak. Also because of this a uniform distribution of these additives inside the fiber layer excluded and the desired effects such. B. uniform vulcanization the crowd, handicapped. As a result of the multitude of treatment stages are also common Damage the edges of the structures, creating waste from trimming. Nonwovens with low fiber weights, e.g. B. those on the square meter less than 100 g of fibers cannot be used at all according to the known method can be processed properly, as they can withstand the stresses and strains of the diverse Treatments are unable to withstand and damage, such as distortions or tears, suffer. Finally, the well-known multi-stage process also has the disadvantage that it cannot be carried out continuously because of the various processes run at different speeds.

These difficulties are solved according to the invention in that the nonwovens only have a one-sided surface consolidation with adhesives with the clearance of gaps and impregnation exclusively or is carried out mainly from the other untreated side. This method allows the use of impregnating agents which have the necessary Ingredients, especially film-forming adhesives, in significantly higher levels Concentration included, so that the substances to be stored in the fiber layer in usually introduced with a single impregnation process and with great uniformity can be distributed throughout the fiber layer.

The impregnating agent is used in foam form with particular advantage.

The impregnation foam can, for. B. on i part of the volume of the impregnation liquid contain up to 5 parts of air. The production can thereby be carried out in the simplest possible way take place that the liquid adhesive, for. B, an aqueous rubber emulsion, the additives, such as wetting agents, anti-aging agents, vulcanizing agents, fillers, Thickeners, finishing agents, may contain, with the addition of foam-forming agents Means such as B. Sodium isobutylnaphthalene sulfonate, and the foam stabilizing Means such as B. methyl cellulose, is whipped into foam. It is advisable, to give the foam a consistency at which it can still flow, the content the impregnation foam to adhesive agents, such as. B. rubber (solid), z. B. about 20 to 40 0 /. The specifically light, flowable foam leaves As was found, easily and evenly through the non-preconsolidated Surface of the fleece that does not have any disruptive resistance to the penetration of the foam prepares, press-fit.

Also for the pre-consolidation of the surface of the fiber fleece before Impregnation, an emulsion converted into foam form is advantageously used, which expediently only a relatively small amount of adhesive, z. B. contains only about 10% Kautschulz (solid). The air content of the pre-consolidation foam is advantageously dimensioned high, e.g. B. such that on i part of the aqueous emulsion about 10 parts of air are used.

The consolidation of the fiber structures impregnated according to the invention can be carried out in a manner known per se. The solidification takes place advantageously by heating and drying, e.g. B. by guiding the impregnated fleece a drying tunnel heated to around 8o to 12o °. Because of the foam impregnation only a relatively small amount of liquid (water) is introduced is a simple one Trouble-free drying guaranteed.

As a base material for the structures to be produced according to the invention Fibers and fiber blends of various types and compositions can be used will. Vegetable fibers such as cotton, flax, Jute, etc., animal fibers such as wool and other animal hair including Human hair, synthetic fibers such as rayon, super polyamide fibers, poly-, rinyl fibers, Polyvinylidene fibers, acrylonitrile fibers, alginate fibers, mineral fibers, such as Glass wool. Also fiber waste products such as V6` full noils, shredded wool, shredded cotton, can be used or used with advantage. The type of applied Fibers and the composition of the fiber mixtures depend on the properties and the intended use of the fabric to be produced. For the production of fabrics which have textile-like properties and Should have a certain elasticity and resilience, fibers are advantageous with elastic properties, such as wool or other elastic animal hair, human hair or mixtures of those with non-elastic fibers, such as. B. cotton is used. It is essential that the fibers are used in a form that can be carded. The length the same should generally be about q to 8 cm, preferably about q. up to 6 cm; but it can also be shorter fibers such. B. those with lengths of 1.5 to q cm, are available be.

Film-forming substances, such as natural ones, are used as bonding agents Rubber, synthetic rubber, rubber-like substances, e.g. B. chlorinated rubber, Polyester, e.g. B. glycol adipic acid, succinic acid esters, silicones, synthetic resins, such as z. B. polyacrylic acid compounds, polyvinyl compounds, polyvinylidene compounds, Polyethylene compounds or mixtures of such substances can be considered. The adhesive are advantageously used in the form of aqueous emulsions or dispersions. Even water-soluble adhesives, such as. B. polyvinyl alcohol can also be used "earth. Important additives include wetting agents, vulcanizing agents, Anti-aging agents and foam-stabilizing agents. In addition, additives, such as thickeners, fillers, individually or in groups. In general it has proven to be expedient to use vulcanizable adhesive agents or to use and to subject the impregnated structures to a vulcanization process.

The content of adhesive agents such as rubber in the aqueous emulsion can e.g. B. 15 to 35 ° jo, preferably about 20 to 25 °% o, be. The salary of wetting agents, such as. B. Sodium isobutylnaphthalene sulfonate, can be up to 15 °,% o, preferably about 7 to 141; o, based on the existing adhesive. Small amounts of phenyl-ß-naphthylamine and as an anti-aging agent are used foam stabilizers small amounts of z. B. methyl cellulose into consideration.

In exercising the invention you can, for. B. proceed as follows: The fibers or fiber mixtures, which may have been subjected to a pretreatment by washing or boiling and drying, are first on the card in thin batts whose weight z. B. is about 5 to 30 g / m2, processed. By laying a number on top of one another, e.g. B. from 3 to 2o, this thin pile and pressure are nonwovens of the desired thickness, the z. B. can have a weight of qo to 350 9 / m2 is generated. In order to give the finished structures the most uniform possible properties against stresses occurring in the longitudinal direction as well as the transverse direction, the thin piles are their. Fibers are partially aligned in the longitudinal direction during carding, offset (angled) one on top of the other in such a way that a tangled fiber system is created in which the fibers of the individual piles are crossed to one another. In order to achieve an intimate union of the individual piles with slight felting as well as compaction and surface smoothing, the multilayer structures are passed through heated press rollers, the z. B. are heated to about 6o to 8o °. Now the one-sided pre-consolidation of the nonwovens takes place, which is carried out in a known manner by spraying on a bonding liquid, but by applying such. B. Spreading a foam-like, highly diluted adhesive with a high air content and subsequent drying is carried out. As a result, the treated surface is covered with a thin, cobweb-like network of the adhesive, through which the contact points of the fibers located on the surface are glued together, leaving free gaps and the fleece is stabilized so that it can be subjected to further treatment without interference.

The one-sided pre-bonded fleece is now through for the purpose of impregnation a horizontal pair of rollers out and thereby the foam-like impregnating agent evenly pressed through the non-pretreated surface in such a way that it the evenly penetrates the entire fiber layer. As impregnation rollers, smooth, preferably polished rollers are used, which are advantageous, e.g. B. by passing through by water. The impregnated fleece is then solidified, preferably by drying, subjected, expediently so that it by one to temperatures from about 8o to 12o ° heated drying tunnel is performed, where appropriate at the same time vulcanization or pre-vulcanization takes place. After drying you can Usual methods of further treatment, such as calendering, can be used. To the Calendering can, if necessary, also include vulcanization or final vulcanization, z. B. by guiding the structure over heated cylinders, the temperature of which ioo ° and can be more, or by z. B. Stay in a heated one for several days Space.

Depending on the type and composition of the fiber material, on the type and composition of the impregnating agent, the proportions of fiber material and impregnating agent and by carrying out the process one can produce products with desired, intended use adapted properties, such as. B. softness, porosity, elasticity, resilience (Crackability), crease resistance, water resistance, wash resistance, sewability, Coloring, etc., achieve.

The amount of impregnating substance introduced into the nonwoven fabric must be dimensioned in such a way that all fibers are glued together and porous structures are created, the z. B. the character before textile fabrics or leather, z. B. chamois leather.

In general it has proven to be advantageous to produce structures which is about 25 to 65 percent by weight, preferably about 35 to 55 percent by weight, Contain impregnation substance and about 75 to 35 percent by weight fiber material, one Thickness of about 0.15 to 1.5, preferably from 0.2 to 0.9 mm, and a soft, supple texture, textile-like or chamois-leather-like Handle and fall, uniform porosity and good elasticity properties own and compared to textile fabrics, the properties of which are in the warp and weft direction differ, the advantage of being the same in all directions Way affecting elasticity = have isoelasticity.

In addition to film-forming adhesives and wetting agents, the aqueous emulsions used for impregnation or fillers and extenders, such as z. B. viscose, methyl cellulose, hide glue, grain flour or other starch products, Kaolin, earth colors, small amounts of water-soluble synthetic resins, e.g. B. polyvinyl alcohol, individually or in groups.

The properties of the fabrics made according to the invention can be influenced in different directions by post-treatment of the same and adapted to the purposes of use.

The invention is suitable, inter alia, for the production of acid-resistant Filter cloths, of dishcloths for the treatment of dishes, glasses, etc., of Shoe lining or intermediate lining, from shoe polishing cloths, abrasive cloths, decorative fabrics, wallpaper-like wall coverings, laminating material for reinforcing foils, etc.

Example i A thin random fiber fleece made of cotton, the weight of which is 70 g / m2, is subjected to superficial pre-consolidation on one side by spreading a mixture of the following composition in the form of a spreadable, air-rich foam with the following composition on one surface of the fleece: Parts by weight Polybutadiene dispersion (40%) ... 250 softened water .............. 750 Sodium isobutylnaphthalene sulfonate 50 Zinc oxide ....................... 5 colloidal sulfur. . . . . . . . . . . . . . 2.6 Vulcanization accelerator ....... I The non-woven fabric, pre-consolidated on one side, is now uniformly impregnated from the non-pre-consolidated side with an impregnating agent in the form of a still flowable foam of the following composition Parts by weight Polybutadiene Dispersion ..........: 250 softened water ............... 36 Alkylbenzenesulfonate .............. 23 Zinc oxide ....................... 5 colloidal sulfur. . . . . . . . . . . . . . 2.6 Vulcanization ultra accelerator ... I The impregnated fleece is solidified by heating and drying and, if necessary, vulcanized or pre-vulcanized and then washed in a padder with water at about 5o ° at a speed of about 6 m per minute and, after washing, for. B. dried by guiding over drying cylinders. Finally, the structure is calendered under moderate pressure, wound up into rolls and these are vulcanized by storing them for about 12 hours in a room heated to about 80 °. The finished product, which has a thickness of about 0.5 mm, can be used as a laminating material for reinforcing foils, e.g. B. paper foils can be used.

Example 2 A fiber mixture consisting of 70 parts by weight of shredded jute and 3o parts by weight of rayon is converted into a tangled fiber fleece, the weight of which 140 g / m2.

For one-sided surface pre-consolidation, a mixture of the following composition is used in the form of a spreadable foam Parts by weight Polyacrylic acid esters as 40% dis- persion ....................... 25o softened water ............... 750 Fatty alcohol sulfonate .............. 6 Methyl cellulose .................. I The impregnation of the structure, which has been pre-solidified and dried on the surface on one side, is carried out with a mixture of the following composition in the form of a flowable foam Parts by weight 60% natural rubber milk 164 softened water ............... 336 Paraffin emulsion (60%). . . . . . . . . 5 Polyethylene oxide derivative .......... 2 Sodium isobutylene naphthalene sulfonate ...................... io Zinc oxide ....................... 5 colloidal sulfur ....... *** '*** 5 Ultra Vulcanization Accelerator .. I. Phenyl-ß-naphthylamine. . . . . . . . . . . 1.8 The impregnated structure is solidified by heating and drying, then subjected to a Leicht_kaland #, g and then washed in a textile washing machine with 50 ° warm water at a rate of about 6 m per minute, dried by being guided over drying cylinders, into rolls of each about zoo m and vulcanized it by storing it for 12 hours in a room heated to about 80 °. The vulcanized structure is sanded on both sides by guiding it through two rotating emery rollers. The finished structure has a thickness of about 0.4 mm; it can be used with advantage as an intermediate shoe lining. Example 3 A fiber mixture consisting of 50 parts by weight of cotton waste and 50 parts by weight of flaky bast is converted into a random fiber fleece, the weight of which is 330 g / m 2.

A mixture of the following composition in spreadable foam form is used for one-sided surface consolidation: Parts by weight 73% natural rubber milk 137 softened water ............... 863 Alkylbenzenesulfonate .............. 18 Zinc oxide ............... .... .... 5 colloidal sulfur ....... - * - 3 Vulcanization ultra accelerator .. Z Methyl cellulose .................. i A mixture of the following composition in the form of a flowable foam is used for impregnation: Parts by weight 73% natural rubber milk 137 softened water ............... 196 Polyethylene oxide derivative ............ i Sodium isobutylnaphthalene sulfonate 12 Zinc Oxide ....................... 15 colloidal sulfur ....... -'- 3 Vulcanization ultra accelerator .. Z Phenyl-ß-naphthylamine .......... . i, 8 The process is carried out in the sense of the examples: [and 2. The product, the thickness of which is approximately 1.4 mm, can advantageously be used as a scouring cloth.

EXAMPLE 4 A tangled fiber fleece made of flake raffia, the thickness of which is 0.6 mm and the weight of 185 g / m 2, is preconsolidated on one side on the surface with a mixture of the following composition converted into foam liquid solid Parts by weight parts by weight Butadiene acrylonitrile polymer, 37o / oig ... 265 Zoo softened water ...... 445 Alkylbenzenesulfonate ..... 20 Zinc oxide active ......... 2.5 Colloidal sulfur. . . . . . . . . 2.5 Vulcanization ultra- accelerator. . . . :. . . . Z Mercaptobenzimide ...... Z, 6 Paraphenylenediamine derivative .... «......... 0.3 A mixture of the following composition in the form of a flowable foam is used for impregnation: liquid solid Parts by weight parts by weight Butadiene acrylonitrile polymer, 37% ... z65 Zoo softened water ...... 120.7 Alkylbenzenesulfonate ..... 20.4 Zinc oxide active. . . . . . . . . 2.5 Colloidal sulfur. . . . . . . . . 2.5 Vulcanization accelerator niger ................ i Mercaptobenzimide ...... 1.6 Paraphenylenediamine derivative .............. 0.3 The process is carried out in accordance with Examples 1 and 2. The product is excellently suited for washing dishes, glasses and the like whose weight is zoo g / m2, is pre-solidified on one side with a mixture of the following composition in foam form: liquid solid Parts by weight parts by weight 730 per cent natural chewing chukmilch .......... 137 Zoo softened water ...... 833 Acrylbenzenesulfonate ..... 16 Paraffin emulsion (30%) 8 2.5 Zinc oxide active. . . . . . . . . 6th Colloidal sulfur. . . . . . . . . 3.3 Vulcanization ultra- accelerator. . . . . . . . . 1.5 A mixture of the following composition in foam form is used for impregnation liquid solid Parts by weight parts by weight 73% natural chewing chukmilch .......... 137 Zoo softened water ...... 263 Alkylbenzenesulfonate ..... 16 Zinc oxide active. . . . . . . . . 6th Colloidal sulfur. . . . . . . . . 3.3 Vulcanization ultra- accelerator. . . . . . . . . 1.5 Phenyl-ß-naphthylamine .. 1.5 The pre-consolidation and impregnation takes place according to Examples i and 2, the impregnated structure is consolidated by drying, then subjected to post-vulcanization and then a treatment in an impregnation bath, e.g. B. a foulard, which has the following composition liquid solid Parts by weight parts by weight 73% natural chewing chukmilch ....... ... 29 21 softened water ...... 8o Alkylbenzenesulfonate ..... 5 After the impregnation has taken place, the structure is dried by being guided over drying cylinders, then rolled up and vulcanized by storing the rolls for about 12 hours in a room heated to about 80 °.

Claims (3)

PATENT CLAIMS: i. Process for the production of porous fiber-containing flat structures by impregnating nonwovens with film-forming adhesives and solidifying the impregnation, characterized in that tangled nonwovens made from cardable fibers are initially solidified by applying small amounts of preferably foam-like adhesives to one side, leaving spaces free, whereupon aqueous film-forming impregnating agents are solidified on the surface . B. dispersions of natural rubber, synthetic rubber or adhesive synthetic resins, which may also contain additives such as vulcanizing agents, finishing agents, fillers, preferably in foam form from the untreated side of the fleece are pressed into the fiber layer, the impregnated structure of a to solidify the impregnation substance serving treatment z. B. fitzen by heating and, if necessary, is also subjected to an after-treatment. 2. Procedure according to claim i, characterized in that the unilateral, with the release of Interstices pre-consolidated random fiber fleece through a gap of two adjacent press rolls is guided and the preferably foam-shaped Impregnating agent through the untreated surface of the fleece in this way is pressed in so that it penetrates the entire fiber layer evenly and that impregnated fleece is solidified by measures such as heating and drying. 3. The method according to claim i and 2, characterized in that the process conditions are set so that a porous sheet is formed which contains about 75 to 3o percent by weight of fiber material and about 25 to 70 percent by weight of impregnation substance and a thickness of about 0.15 to 1 .5 mm, preferably from about 0.2 to 0.6 mm.