Chemistry: molecular biology and microbiology – Process of utilizing an enzyme or micro-organism to destroy... – Textile treating
Reexamination Certificate
1998-04-29
2001-07-17
Achutamurthy, Ponnathapu (Department: 1652)
Chemistry: molecular biology and microbiology
Process of utilizing an enzyme or micro-organism to destroy...
Textile treating
C435S067000, C435S200000, C435S202000, C435S209000, C435S252300, C435S264000, C510S303000, C510S320000, C536S023200
Reexamination Certificate
active
06261828
ABSTRACT:
The present invention relates to a desizing and “stone-washing” one-step process whereby dyed denim having localized variation in colour density of improved uniformity is achieved by treating dyed denim, especially dyed denim garment such as denim jeans, with an amylolytic enzyme and two different endoglucanases in the very same process step.
BACKGROUND OF THE INVENTION
During the weaving of textiles, the threads are exposed to considerable mechanical strain. Prior to weaving on mechanical looms, warp yarns are often coated with size starch or starch derivatives in order to increase their tensile strength and to prevent breaking. The most common sizing agent is starch in native or modified form, yet other polymeric compounds such as polyvinylalcohol (PVA), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA) or derivatives of cellulose (e.g. carboxymethylcellulose (CMC), hydroxyethylcellulose, hydroxypropylcellulose or methylcellulose), may also be abundant in the size.
In general, after the textiles have been woven, the fabric proceeds to a desizing stage, followed by one or more additional fabric processing steps. Desizing is the act of removing size from textiles. After weaving, the size coating must be removed before further processing the fabric in order to ensure a homogeneous and wash-proof result. The preferred method of desizing is enzymatic hydrolysis of the size by the action of amylolytic enzymes.
For the manufacture of denim clothes, the fabric is cut and sown into garments, that is afterwards finished. In particular, for the manufacture of denim garment, different enzymatic finishing methods have been developed. The finishing of denim garment normally is initiated with an enzymatic desizing step, during which garments are subjected to the action of amylolytic enzymes in order to provide softness to the fabric and make the cotton more accessible to the subsequent enzymatic finishing steps.
Cotton wax and other lubricants can be applied to yarns in order to increase the speed of cotton weaving. Also waxes of higher melting points are being introduced. Wax lubricants are predominantly triglyceride ester based lubricants. After desizing, the wax either remains or redeposits on the fabric and as a result, the fabric gets darker in shade, gets glossy spots, and becomes more stiff.
International Patent Application No. WO 93/13256 (Novo Nordisk A/S) describes a process for the removal of hydrophobic esters from fabric, in which process the fabric is impregnated during the desizing step with an aqueous solution of lipase. This process has been developed for use in the fabric mills only, and is carried out using existing fabric mill equipment, i.e. a pad roll, a jigger, or a J box.
JP-A 2-80673 discloses a method whereby desizing and softening are achieved by treating cellulose fibres with an aqueous solution containing both amylase and cellulase.
For many years denim jeans manufacturers have washed their garments in a finishing laundry with pumice stones to achieve a soft-hand as well as a desired fashionable “stone-washed” look. This abrasion effect is obtained by locally removing the surface bound dyestuff. Recently cellulytic enzymes have been introduced into the finishing process, turning the stone-washing process into a “bio-stoning process”.
The goal of a bio-stoning process is to obtain a distinct, but homogeneous abrasion of the garments (stone-washing appearance). However, uneven stone-washing (“streaks” and “creases”) are very frequently occurring. In consequence repair work (“after-painting”) is needed on a major part (up to about 80%) of the stone-washed jeans that have been processed in the laundries.
Thus, it is an object of the present invention to provide a process which reduces the problem of streaks and creases on the finished denim garments.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a process for the treatment of fabrics, which process improves the color distribution/uniformity, stone-wash quality, etc., and which reduces the need for after-painting of the finished clothes.
The invention provides a one-step process for enzymatically desizing and stone-washing dyed denim, which process comprises treating the denim with an amylolytic enzyme, such as an &agr;-amylase, in combination with a first abrading monocomponent endoglucanase and a second streak-reducing monocomponent endoglucanase.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a process for enzymatic treatment of fabrics, by which process it is possible to provide desized and enzymatically stone-washed dyed denim of improved visual quality.
As described above, enzymatic treatment of fabrics conventionally includes the steps of desizing the fabric by use of amylolytic enzymes, softening the garment (including the steps of bio-polishing, bio-stoning and/or garment wash) by use of cellulytic enzymes, optionally followed by dyeing the garment, washing the garment, and/or softening the garment with a chemical softening agent, typically a cationic, sometimes silicone-based, surface active compound. The process of the present invention may conveniently take place during the desizing and/or softening step of the conventional garment manufacturing steps.
Accordingly, in a preferred embodiment, the process of present invention relates to a one-step process for combined desizing and “stone-washing” of dyed denim, wherein the denim is treated with an amylolytic enzyme, such as an &agr;-amylase, in combination with a first abrading monocomponent endoglucanase and a second streak-reducing monocomponent endoglucanase.
In the present context, the term “abrading endoglucanase (or cellulase)” is intended to mean an endoglucanase which is capable of providing the surface of dyed denim fabric (usually sown into garment, especially jeans) localized variations in colour density. Examples of abrading cellulase are those mentioned in the International Patent Application PCT/US89/03274 published as WO 90/02790 which is hereby incorporated by reference.
The term “monocomponent endoglucanase” denotes an endoglucanase which is essentially free from other proteins, in particular other endoglucanases. Monocomponent endoglucanases are typically produced by recombinant techniques, i.e. by cloning and expression of the relevant gene in a homologous or a heterologous host.
In the present context, the term “streak-reducing endoglucanase (or cellulase)” or “levelling” endoglucanase is intended to mean an endoglucanase which is capable of reducing formation of streaks usually present on the surface of dyed denim fabric (usually sown into garment, especially jeans) which has been subjected to a “stone-washing” process, either an enzymatic stone-washing process or process using pumice for providing localized variations in colour density on the denim surface. Examples of streak-reducing or levelling cellulases are those mentioned in the International Patent Application PCT/DK95/00108 published as WO 95/24471 which is hereby incorporated by reference.
The first endoglucanase is preferably a fungal EG V type cellulase. Another useful endoglucanase is a fungal EG III type cellulase obtainable from a strain of the genus Trichoderma. Examples of useful fungal EG III type cellulases are those disclosed in WO 92/06184, WO 93/20208 and WO 93/20209, and WO 94/21801 which are hereby incorporated by reference.
Preferably, the EG V type endoglucanase is derived from or producible by a strain of Scytalidium (f. Humicola), Fusarium, Myceliophthora, more preferably derived from or producible by
Scytalidium thermophilum
(
f. Humicola insolens
),
Fusarium oxysporum
or
Myceliophthora themophila,
most preferably from
Humicola insolens,
DSM 1800,
Fusarium oxysporum,
DSM 2672, or
Myceliophthora themophila,
CBS 117.65.
In one embodiment of the invention, the first endoglucanase is an endoglucanase comprising the amino acid sequence of the
Humicola insolens
endoglucanase shown in SEQ ID No. 1 or is an analogue of said endoglucanase which is at least 60% homologous with the sequence shown in SEQ ID N
Achutamurthy Ponnathapu
Green, Esq. Reza
Lambiris Esq. Elias J.
Moore William W.
Novo Nordisk A S
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