DE965442C - Process for the production of porous bodies - Google Patents

Description

ISSUED JUNE 6, 1957

G8io6IVb / 39b

It is known to use short-staple rayon threads, so-called fiber filaments, of about 0.5 to 5 ^mm fiber length or fiber dust of unequal fiber length for dusting on paper, cardboard, textiles or plastic films. The material is sieved, dusted, blown or applied by suitable electrical fields onto the base previously provided with an adhesive coating. As a result, a refinement of the surface of the materials mentioned is achieved, the z. B. obtained a plush, velvet or suede character. The fibers are only held at one end, and the products obtained inevitably have a flat character.

It is also known to use viscose short-cut fiber material, e.g. B. asbestos fibers to be mixed in, in order to give the products made from them, such as bottle caps and the like, a silk gloss. It has also been proposed to use fibroin solutions to make nonwovens made from cut fiber material soak and coagulate the fibroin to obtain suede-like webs, or kneading fiber materials into a solution of celluloid, which can then be mixed with any counter-

709 532/293

stands can be deformed. These proposals concern the use of short cut fibers, that of the fibers to be processed Mass to solidify or beautify the achieved products can be added. Porous products however, were not obtained in this way.

The subject of the present process, however, is the production of porous bodies. It was ίο found that it is possible to connect individual fibers or powder grains to one another in such a way that a three-dimensional network of fibers or grains is created at their points of contact are glued together. Such a loose, glued arrangement of fibers is according to the invention achieved in that the fibers are combined into a cone of fiber dust by means of an air nozzle. be dusted, in which a binder is sprayed at the same time.

An example of a suitable nozzle arrangement is shown in the drawing.

The supply of the fiber material, which in a suitable manner, e.g. B. metered by a feed screw is done through the horizontal feeder channel i. The fibers fall into the funnel space 2, where they are captured by an air stream from the tube 6 and atomized. Feeding the press. air takes place through the pipe attachment 5. The binding agent is fed through pipe 3 to the nozzle 7 and sprayed from tube 4 by a stream of compressed air. Because of the separate air connections it is possible to regulate the air volume of each nozzle individually. But both nozzles can also be switched off a common air line. The two nozzles can also be separated from each other be arranged, and the atomization of the binder can also be carried out in a known manner be done by liquid pressure alone without the aid of compressed air. Also the fiber material can instead of nozzles with mechanical devices, e.g. B. Vibrating sieves, are finely distributed. In all cases, however, it is necessary that dusted fibers and binders are already before Mix down the material in the airspace.

When this stream of dusted at the same time

When fibers and binders are directed against a solid surface, a porous structure is created Fibers that can be produced in any thickness and are capable of a wide range of applications.

Any fiber material or powder that has been cut, milled or other treatment can be processed into a loose, sprayable product, such as a) natural cellulose fibers, e.g. B. wood pulp fibers, linters, ramie, jute, ground or sanded Wood;

b) man-made fibers made from cellulose or cellulose derivatives, cut into suitable stacks such as viscose, cupric ammonia, acetate, nitrocellulose fibers;

c) cellulose or cellulose derivative powder, obtained from cellulose solutions such as viscose, Copper oxide ammonia cellulose, nitrocellulose, acetyl cellulose solutions, or powder from ground Cellulose;

d) fibers made of fully synthetic material, such as polyamides, polyacrylonitrile;

e) Fibers made of inorganic material such as glass, asbestos, slag wool and the like.

As binders for the bonding are z. B. suitable:

a) Solutions of cellulose derivatives, synthetic resins, natural resins and combinations this (if necessary under 'plasticizer additive);

b) aqueous solutions of glue, gelatin, cellulose derivatives, viscose;

c) polymerizable or curable resitols or resitol solutions.

When the fiber material or powder is soluble in or with certain solvents becomes sticky or if it is superficially in a solvent-soluble or therefore sticky Form can be converted, the solvents themselves, optionally with the addition of plasticizers, serve as binders.

The porous bodies obtained in this way can be used, for. B. for the production of

a) Insulation panels against heat or sound or for fire protection, in this case made of asbestos or Fiberglass;

b) Gunning compounds for spraying onto objects to be isolated, such as boilers, pipelines, Door fillings;

c) quilt-like products, padding substitutes;

d) all objects or materials for which the requirement of high absorbency with low Strength is provided;

e) medical-cosmetic products such as tampons, compresses, sanitary towels.

The bodies produced by the method described can be produced with volume weights down to about 0.03 g / cm ³ , depending on the fiber material and air speed in the nozzles. They retain their shape even when they are wetted with or when liquids are sucked in, as long as these do not dissolve the binding agent. It can, for. B. 8 to 10 times the fiber weight of water can be absorbed or absorbed.

Also noteworthy is the fact that the inner surface z. B. of cellulose material of 2 m ² / g is not measurably reduced by the gluing process.

Embodiment

Viscose rayon with a staple length of 1 mm and a single titer of 1.4 denier, with a finishing agent 0.2% of a condensation product of stearic acid and ethylene oxide was provided, is with twice the weight of a solution of 20 g of a Celhilose acetate., z. B. "Cellit", and 10 g of dimethyl glycol phthalate as a plasticizer per liter against a suitable under-

layer is sprayed, whereby a fiber layer of any thickness with a weight of 4 g / 100 cm ^{3 is} obtained, which has an absorption capacity of about 10 times the fiber weight compared to water.

Claims (1)

PATENT CLAIM: Process for the production of porous bodies from a mixture of fibers or powder and binders, characterized in that the individual components are dusted mixed in the air stream and precipitated together. Considered publications: German Patent Specifications No. 529529, 664077; Swiss patent specification No. 116 363. 1 sheet of drawings © 609 738/394 12.56 (709 532/293 5. 57)