Rhodia Ag

Rhone-poulenc Rhodia Aktiengesellschaft

Rhodia Acetow Aktiengesellschaft

Gunter Maurer

Ties Karstens

Eberhard Teufel

Paul Rustemeyer

Joachim Schatzle

Klaus Albien

The disclosure relates to a melt-blown non-woven fabric based on cellulose esters, with fibers of mean diameter less than about 10 microns. The fabric contains 0-10 wt. % extractable softener, has a reflection factor determined according to DIN 53 145 Part I (1992) of more than 60% and the cellulose ester has a degree of substitution DS of about 1.5-3.0. The softener is preferably water-extractable. A melt-blown non-woven fabric is produced with the cellulose ester as follows: a cellulose ester, cellulose acetate, with a DS of about 1.5-3.0, in particular 1.7-2.7, is mixed with softener in a weight ratio of about 2:1 to 1:4 and simultaneously heated and melted. The mixture of softener and cellulose ester has a melting index MFI (210/2.16) according to DIN 53 735 of about 400 to 5 g/10 min., in particular 300 to 50 g/10 min. The melt is worked in a melt-blown spinning device into a melt-blown non-woven fabric and the softener is then extracted with a softener solvent to leave a proportion of 0-10 wt. %. The melt-blown non-woven fabric is especially suitable as a filter material.

Melt-blown nonwoven fabric, process for producing same and the uses thereof

There are described filaments on the basis of a cellulose acetate soluble in acetone, the degree of polymerization (DP) of the cellulose acetate being between about 110 and 210 and the degree of substitution (DS) preferably between about 2.2 and 2.7. Optically isotropic spinning solutions can be obtained, the cellulose acetate concentration of which is about 35 to 47 mass-%. When such an optically isotropic spinning solution is spun, in particular by dry spinning, filaments are obtained in a profitable manner because the costs connected with the recovery of the acetone can be appreciably lowered, without impairing the desirable properties of the filaments, which are suitable in particular for the production of cigarette filter tow.

Cellulose acetate filaments, an optically isotropic spinning solution

Consolidated nonwoven fabrics and the process of producing theme is disclosed. The fabrics absorb water and substances with oleophilic and/or lipophilic properties. The inventive process includes blow-spinning a melt or a solution of a spinnable polymeric material to textile fibers and/or filaments, preferably having a diameter of 0.1 to 6 .mu.m, more preferably 0.5 to 3 .mu.m, transforming these textile fibers and/or filaments to a nonwoven fabric, consolidating this fabric and applying a wetting agent to the fabric. Consolidation is accomplished by means of water jets, then a zwitterionic or cationic surfactant is applied to the fabric in a wet-in-wet procedure during or immediately after the water-jet consolidation, and the fabric is dried; these procedures are performed continuously. A polyester or a polyamide is used preferentially as the polymeric material.

Consolidated nonwoven fabrics and process for producing them

A filter for separating substances having lipophilic and/or oleophilic and/or apolar properties, such as fats, oils, substituted or unsubstituted hydrocarbons, from different liquids, gases and vapors, such as water, (moist) air and water vapor, employing polyolefin fibers and/or filaments which have a diameter of 0.1 to 10 82 m, and preferably 0.5 to 2 .mu.m, as filter material. The filter material is present in the form of bands or strands which are of finite or infinite length, and which are formed from webs, waddings or other sheet-like structures made of such fine fibers and/or filaments and which are arranged with respect to each other in such a way that free openings and passages are in between them. The filter material perferably consists of polyethylene and/or polypropylene fibers and/or filaments.

Growing community of inventors

Neuenburg, Germany

Gunter Maurer