Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-02-15
2004-06-01
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C008S101000, C008S107000, C008S111000, C008S115510
Reexamination Certificate
active
06743761
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the one step preparation of textile components and, more particularly, to the simultaneous de-sizing and bleaching of textile components such as woven fabrics, fibers or yarns through the use of hydrophobically activated bleaching systems.
BACKGROUND OF THE INVENTION
In the textile processing of natural fibers, yarns and fabrics, a pretreatment or preparation step is typically required to properly prepare the natural materials for further use and in particular for the dyeing and/or finishing stages typically required for commercial goods. These textile treatment steps remove impurities and color bodies, either naturally existing or those added by the spinning and weaving steps to the fibers and/or fabrics.
While textile treatments may include a number of varying treatments and stages, the most common include: singeing—the removal of loose or miscellaneous fibers from the surface by burning with a flame; de-sizing—the removal of sizing agents, such as starches, via enzymatic, alkali or oxidative soaking; scouring—the removal of greases, oils, waxes and fats by contact with a solution of sodium hydroxide at temperatures near boiling; mercerization—the application of high levels of sodium hydroxide in conjunction with stretching and pulling of the fabrics for increased fiber strength and bleaching—the use of hydrogen peroxide bleaching systems at temperatures near boiling for the removal of color bodies and whitening of fabrics.
Commercial processing typically requires the separation of these pretreatment steps due to the broad variation of conditions present in each of the steps. However, this separation of treatment steps leads to heavy additional costs added to the overall treatment process due to the requirement of multiple rinsing and/or drying steps required between the respective stages. The additional rinse and/or drying steps add enormous addition costs and waste materials to the treatment process.
Accordingly, the combination of various pre-treatment stages into a one-step treatment would have a significant impact in the commercial treatment of textiles in the form of reduced costs and waste materials over the commercial processes typically employed. Three treatment stages which are commonly investigated for combination into a one-step process are de-sizing, scouring and bleaching.
However, the combination of these three common steps has previously been unsatisfactory. Currently employed bleaching technology involves the use of hydrogen peroxide bleaching at temperatures in excess of 95° C. Such high temperatures and strong bleaching systems are wholly incompatible with the amylase enzymes necessary in a de-sizing operation. Thus, the combination of the de-sizing and bleaching technology at temperatures in excess of 95° C. leads to destruction of the de-sizing enzymes and a unsatisfactory de-sizing result. Alternative de-sizing techniques such as alkali or oxidative soaking involves the use of aggressive chemicals which lead to fiber damage. On the other hand, reduction of the temperature at which the one-step treatment is conducted to allow effective enzymatic de-sizing results in an unacceptably poor bleaching with whiteness values below the commercially acceptable limit.
Lower temperature bleaching systems have been investigated in textile processing to little commercial success. Hydrophilic activation of the hydrogen peroxide has been attempted. In particular, tetra acetyl ethylene diamine or TAED is a common hydrophilic bleach activator widely accepted in the consumer laundry bleaching applications to provide effective bleaching at lower wash temperatures. TAED has been taught in hydrogen peroxide textile bleaching, and in particular in the bleaching of regenerated cellulosics such as rayon. However, while TAED has allowed lower bleaching temperatures, it has proven to provide little advantage in the fabric strength reduction which results from high temperature bleaching and has not provided the satisfactory whiteness profiles necessary for commercial goods. In addition, the poor water solubility of TAED limits its application in textile processing.
Hydrophobic bleach activators, such as nonanoyloxybenzene sulfonate, sodium salt (NOBS) have been employed in consumer laundry detergent applications such as Tide® with Bleach to work in conjunction with peroxygen sources to provide activated bleaching in consumer laundering of garments. Activated bleaching in consumer home laundry conditions allows effective cleaning of certain soils and stains in cold water temperatures. The use of hydrophobic systems has been limited in a home consumer laundry environment due to the formation of diacyl peroxides in the wash solution. Diacyl peroxides degrade natural rubber components into which they come in contact. Thus, sump hoses, rubber gaskets, etc in laundry machines have prevented explotation of this technology in certain geographies.
The severe conditions employed in the bleaching of textiles have heretofore prevented the successful application of laundry detergent bleaching technology in textile mill applications. Indeed, EP 584,710 discloses the use of activated bleaching in textile mill applications wherein NOBS is briefly disclosed along with a multitude of other classes and types of activators. While NOBS is disclosed, there is no successful application of hydrophobic bleaching technology where acceptable whiteness values are achieved while damage to fabrics and fibers is minimized. Indeed, EP 584,710 specifies that in order to achieve acceptable whiteness benefits, additional alkali bleaching is necessary which will dramatically increase fiber damage.
Accordingly, the need remains for an effective one step textile treatment process and in particular for the combination of de-sizing, scouring and bleaching in textile treatment which can provide superior wettability and whiteness benefits while providing improved fabric strength retention and reduced fiber damage versus conventional textile bleaching processes.
SUMMARY OF THE INVENTION
This need is met by the present invention wherein a one step or simultaneous treatment method for textiles and superior performing fabrics obtained therefrom is provided. The method of the present invention provides textiles with commercially acceptable whiteness profiles and superior fabric strength retention and fiber damage properties to fibers processed via the method. The method of the present invention involves the combination of de-sizing and a peroxide based bleaching system via the use of hydrogen peroxide and a hydrophobic bleaching agent such as an activator or a hydrophobic peracid. . In addition, the method of the present invention allows for significant cost reduction in the operation of a textile bleaching process through the one step treatment of textiles and the use of significantly lower bleaching temperatures than conventional peroxide bleaching and much shorter processing times, particularly in batch processing.
While not wishing to be bound by theory, it is believed that the hydrophobic bleach species of the present invention provide better absorbency on the fabrics and yarns and better “wetting” of the surface of the fibers than conventional peroxide bleaching techniques or hydrophilic activators. Hydrophobic bleach activators form the active bleaching species, peracid, on the surface of the fabric allowing a longer time on the surface of the fabric. Hydrophilic activators, meanwhile, form peracid in solution and must then undergo a fabric solution interaction which is less efficient. As a result, the hydrophobic activators of the present invention provide superior bleaching and whiteness while minimizing fiber damage and strength reduction.
According to a first embodiment of the present invention, a method for the simultaneous treatment of non-finished textile components is provided. The method comprises the steps of providing a non-finished textile component such as a fiber, yarn or fabric, saturating the textile component with an aqueous treatment solution comprising
Bolam Brian M.
Corstanje Brahm J.
Elhilo Eisa
Gupta Yogendra N.
The Procter & Gamble & Company
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