Bleaching and dyeing; fluid treatment and chemical modification – Bleaching – Chemical
Patent
1995-11-15
1998-10-13
Diamond, Alan
Bleaching and dyeing; fluid treatment and chemical modification
Bleaching
Chemical
8137, 8138, 435263, D06L 302, D06L 114
Patent
active
058206361
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP94/01507 filed May 10, 1994.
The present invention relates to an improved process for the continuous pretreatment of cellulosic textile material comprising surfactants and other customary auxiliaries with or without customary enzymes as desizing agents and has a pH of from 5 to 11, and, after wash off and rinse, which comprises customary surfactants and other customary auxiliaries,
Wovens are customarily subjected to a three-stage pretreatment comprising desizing, scouring and bleaching. Each of these three treatment steps divides into an impregnating step, in which the treatment liquor is applied to the textile material, a dwell stage, in which the chemicals and auxiliaries applied to the textile material can react, and a washoff stage.
The present pretreatment process allows significant gains to be made in efficiency. All that is required to obtain good bleach results with a minimum of fabric damage is a precleaning step, wherein the treatment liquor (impregnating liquor), which contains certain additives, is applied to the textile material and washed off immediately thereafter, without dwell time, and also a bleach directly thereafter. Particularly good bleach results are obtained on impregnating with an increased bleaching liquor add-on. These good results, which substantially correspond to those of the customary three-stage pretreatment, were unforeseeable.
If the precleaning liquor of (a) does not contain the additives mentioned hereinafter, then the bleach results will be poor. In the case of difficult-to-remove, water-insoluble starch sizes on the fabric, the desizing effect may not be sufficient in some cases. In these cases, the impregnation of (a) has to be additionally followed by a desize with customary starch-degrading enzymes. However, in such cases it is more sensible to carry out the present pretreatment process after the desize by adding the below-mentioned additives to the first or second wash bath at the end of the desizing process. It is also possible to add the below-mentioned additives directly to the desizing liquor which contains the starch-degrading enzymes.
All the process variants mentioned surprisingly give good bleach results which are at least comparable to those of a customary three-stage procedure.
Cotton as a natural product includes, in addition to its main component, cellulose, up to 10% by weight of natural impurities which can vary greatly depending on origin, provenience, growth conditions and ripeness at the time of harvest. Such natural concomitants of cotton are in particular proteins, pectin, waxy esters and waxy alcohols, hemicellulose, lignin substances, resins, colored pigments, organic acids and mineral salts with the cations of Ca, Mg, Na, K, Fe, Mn, Cu and Al and the anions carbonate, phosphate, sulfate, chloride and silicate.
These impurities mean that raw cotton is completely water-repellent and has a harsh, unacceptable hand and also a yellowish/brownish appearance and would lead to appreciable problems in bleaching, dyeing or printing. Therefore, they must first be removed as completely as possible.
In addition to these natural concomitants, there are also substances applied, purposively or inadvertently, during growth and in the course of the processing stages. Here a distinction has to be made between substances applied in the course of growth and harvest (eg. leaf and stem remains, defoliants, insecticides, fungicides), substances applied in the course of yarnmaking and processing (eg. spin finishes, detrital metal, rust stains), substances applied in the making of knits, and substances applied in the making of wovens.
Weaving imposes mechanical stresses on the warp threads, from which they have to be protected by polymer films surrounding them. The sizes applied for this purpose, which differ very widely in constitution and solubility (examples being starch, starch ethers, starch esters, carboxymethyl starch, carboxymethylcellulose, methylcellulose, polyvinyl alcohol, polyacrylates), additionally include sizing aids
REFERENCES:
patent: 2960383 (1960-11-01), Potter et al.
patent: 4426203 (1984-01-01), Abel et al.
patent: 4539353 (1985-09-01), Abel et al.
Database WPI, Section Ch, Derwent Publications, Ltd., London, GB; Class E17, AN 71-50269s, abstract for JP, B, 46-026426 (month unknown), 1971.
Angstmann Heinz-Dieter
Bassing Dieter
Freyberg Peter
BASF - Aktiengesellschaft
Diamond Alan
LandOfFree
Continuous pretreatment of cellulosic textile material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Continuous pretreatment of cellulosic textile material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Continuous pretreatment of cellulosic textile material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-309142