Bleaching and dyeing; fluid treatment and chemical modification – Chemical modification of textiles or fibers or products thereof – Cellulose fibers
Reexamination Certificate
2000-09-19
2002-09-24
Delcotto, Gregory (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Chemical modification of textiles or fibers or products thereof
Cellulose fibers
C008S116400
Reexamination Certificate
active
06454814
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to treatment of fabrics.
2. Description of Prior Art
Many fabrics are inherently or otherwise impervious to water and therefore difficult to wash. If the surface of the fabric is treated to improve washability, the effect of the treatment significantly deteriorates or is removed by subsequent and normal washing operations.
The present invention is applicable to cotton/polyester blended fabric. Many proposals have been made already to increase the water absorbency or hydrophilicity of cellulose-containing materials. Most of such proposals use graft-copolymerisation with a monomer containing hydrophilic groups on the cellulose containing material. The usual method uses graft copolymerisation with monomers such as acrylonitrile and/or acrylate and methacrylate ester followed by alkaline hydrolysis. Only a low homopolymer is formed.
In the Journal of Applied Polymer Science Vol. 25(1980) at page 535, J. L. William et al have described a method of hydrophilic treatment of cellulose containing materials. A similar method is described in Progress Polymer Science Vol. 10(1984) at page 1. U.S. Pat. No. 3,423,163 discloses a method of increasing moisture absorbing properties of cellulose materials by graft copolymerisation using N-methylolacrylamide. U.S. Pat. No. 3,252,880 discloses that a base polymer may be rendered more hydrophilic by grafting thereon suitable monomer materials. U.S. Pat. No. 3,514,385 discloses the grafting of various acrylic compounds to cellulosic base materials in order to increase the hydrophilicity of the resulting products. U.S. Pat. No. 3,201,336 further discloses grafting arcylic monomers onto cellulosic-based materials. U.S. Pat. No. 4,036,588 discloses the grafting copolymerization of various kinds of hydrophilic monomers onto cellulose-containing materials after the materials have been treated by gamma rays, and then the grafted fibers are treated by post-decrystallization using a solution of zinc chloride.
The products obtained by the above stated methods have good ion-exchange properties, and good water absorbency provided by their alkali metal salts. However, when the above treatments are applied to cotton containing fabrics, serious strength loss is observed, which greatly prevents their use on many occasions and the fabric may not be reusable.
SUMMARY OF THE INVENTION
It is an object of the invention to overcome or at least reduce this problem.
According to the invention there is provided a method of treating cellulose fibre or blended fiber pieces thereof, to increase water absorptive and hydrophilicity by graft polymerisation, the method comprising the steps of pre-treating the piece in a solution of an inhibitor for about one hour, washing the piece to remove excess inhibitor solution, placing the piece in a grafting solution of hydrophillic monomer for about three hours, washing in methanol, decrystallise treating the piece using a solution of zinc chloride for about one hour, and then treating the decrystallised piece in a solution of sodium hydroxide at 50° C. for about one hour.
The blend fabric may be a cotton/polyester blend.
The inhibitor may be ceric ammonium sulphate.
The inhibitor may be potassium persulfate (KPS).
The grafting solution may be acrylic tetrachloroethylene.
The grafting solution may be methyacrylic acid.
REFERENCES:
patent: 3201336 (1965-08-01), Magat et al.
patent: 3252880 (1966-05-01), Magat et al.
patent: 3423163 (1969-01-01), Magat et al.
patent: 3514385 (1970-05-01), Magat et al.
patent: 4036588 (1977-07-01), Williams et al.
patent: 4065256 (1977-12-01), Igeta et al.
patent: 4806125 (1989-02-01), Dyer
Li Yi
Lin Kwok Yi
Xu Weilin
Yeung Kwok Wing
Delcotto Gregory
Hong Kong Polytechnic University
Kumar Preeti
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