Verfahren zur Herstellung von ungewebten Fasergebilden

摘要

876,444. Agglutinated fibrous materials; laminates. FREUDENBERG KOMM.-GES. AUF. AKTIEN, CARL. Nov. 24, 1958 [Nov. 25, 1957], No. 37778/58. Class 140. A method of producing bonded unwoven fibre structures comprises treating fibres, at least a portion of which are water-soluble, e.g. 1% to 60% by weight, with an aqueous impregnating liquid so that the water-soluble fibres are partially dissolved, removing the excess liquid from the fibres, and drying the fibres at elevated temperatures, e.g. 90‹ C. to 175‹ C. Suitable fibres, which may be hollow or crimped, capable of being dissolved by aqueous liquids are fibres of unhardened polyvinyl alcohol or unhardened protein, alginate, methyl cellulose, polymethacrylic acid, carboxymethylcellulose, hydroxyethylcellulose, polyvinylethyl ether, and maleic anhydride copolymer. Impregnation may be carried out by dipping or padding. Suitable impregnating liquids are water and aqueous solutions, emulsions or dispersions. The impregnating liquids may contain film-forming bonding agents, e.g. natural or synthetic rubber or synthetic resin, whereby the bond between the fibres and the flexibility and elasticity of the finished web may be improved, or the liquid may contain a silicone oil. The fibre mixture may be converted into a bound web by passing the mixture, distributed on supporting means such as a wire mesh belt, through a padder filled with impregnating liquid, freeing the web from excess liquid by squeezing or vacuum means and subsequently drying the web under pressure, as by conducting it through a heated felt calender. The web may be rendered resistant to boiling water by employing an aqueous solution of formaldehyde as the impregnating liquid. Multiply structures may be formed by placing thin woven or knitted fabrics either upon or between webs of fibres (as above) and then impregnating the assembly and subsequently drying it under heat and pressure. Examples describe the treatment of webs comprising fibres of cotton and polyvinyl alcohol; rayon and polyvinyl alcohol; and polyester and polyvinyl alcohol: with water, or (to make the product resistant to boiling water), an aqueous solution of formaldehyde, sodium sulphate and hydrochloric acid or an aqueous solution of formaldehyde : and drying by means of a felting calender or rotary cloth press.