Bleaching and dyeing; fluid treatment and chemical modification – Chemical modification of textiles or fibers or products thereof
Reexamination Certificate
1998-01-08
2001-04-10
Cole, Elizabeth M. (Department: 1771)
Bleaching and dyeing; fluid treatment and chemical modification
Chemical modification of textiles or fibers or products thereof
C008S137000, C008S529000, C008S115700
Reexamination Certificate
active
06214058
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to fabrics and yarns made from melamine fibers and processes for imparting physical characteristics, such as color, moisture regain and improved hand to them.
BACKGROUND OF THE INVENTION
Melamine fibers are useful in applications requiring resistance to heat and flame. Examples of such applications include upholstery, drapery material, fire fighting apparel, etc. Such applications might be considered so utilitarian because of their role in preserving life and property that appearance is a minor secondary consideration. This is not true, however, and style plays an important part of fabric selection. Therefore, it is important that the fabrics made with melamine be dyeable to desired shades. Because the chemistry of the melamine fiber is different than the more commonplace man-made synthetic fibers, the dyestuffs known to dye these more common fibers do not necessarily dye melamine fibers. As a result, there is a need to find dyestuffs and conditions that will dye the melamine fabrics.
Many melamine fabrics in their natural state may have a harsh or itchy hand. In certain applications of melamine fabrics, this characteristic is viewed as a drawback to using melamine fabrics even when the protective performance is superior. Methods to increase the comfort and improve the hand of melamine fabrics are desirable.
Comfort may also be linked to “moisture regain” so that for some fabrics, one method for improving comfort is to increase “moisture regain”. It is believed that the ability of a synthetic fiber to absorb moisture makes such fibers more like cotton and less synthetic feeling against the skin. Moisture regain refers to the characteristic of fabrics to absorb moisture. Cotton fabrics, which are traditionally viewed as comfort fabrics, have relatively high moisture regain properties (typically in the range of about 8.5 to about 10.5) which allows wicking action to remove moisture from the skin resulting in a comfortable “feel”.
Softness is an attribute of hand that some consider to defy quantitation. However, when manually comparing the softness of two different fabrics, there is general agreement on which one is softer.
Melamine fibers are often blended with other fibers such that most melamine fabrics are actually blends of melamine and other types of fiber. Melamine fibers are blended with a large variety of fibers, for example, p-aramids, m-aramids, glass, flame resistant (FR) cellulosic fibers, steel cotton, wool polyester, etc. The same concerns of dyeability and hand apply to fabrics made from blends of melamine fibers and other fibers as apply to all melamine fabrics. Methods for dyeing these fabrics and also improving the hand are desirable.
In addition, novel color effects are sought in the industry. Dyeing methods that cause unique or attractive appearances in the fabric subjected to the method are considered beneficial. One popular color effect is called “chambray”. Chambray fabrics are exemplified by worn denim jeans. Usually, this effect is accomplished by process steps, e.g., stone washing, after the dyeing process. In addition, the denim effect is usually achievable with dyes that do not exhibit good washfastness to cellulosic materials combined with the use of undyed warp yarns in the starting fabric. Upon washing, certain dyes exhibit poor fastness to washing resulting in a lighter appearance and more noticeable uncolored warp yarns.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for dyeing melamine fabrics.
It is another object of the present invention to provide a dyed melamine fiber fabric.
It is a further object of the present invention to provide a method for dyeing melamine fiber blend fabrics.
It is a still further object of the present invention to provide a dyed melamine fiber blend fabric.
It is yet another object of the present invention to provide a method to improve the hand of melamine fiber and melamine fiber blend fabrics.
It is still another object of the present invention to provide a melamine or melamine blend fabric with good hand characteristics.
These and related objects and advantages are achieved with a process for improving the comfort of fabrics made from melamine fibers by submerging the fabrics in an aqueous bath heated to more than 70° C. for more than 20 minutes. The aqueous bath may be substantially all water or it may be a dyebath. The aqueous bath may contain one or more solutes selected from leveling agents; dispersing agents; chelating agents; lubricating agents; pH adjustment agents; and combinations thereof. The bath is preferably heated to a temperature from about 90° C. to about 130° C. The fabric may comprise a blend of melamine fibers and other fibers. The melamine fibers are preferably melamine-formaldehyde fibers comprising the condensation product of melamine and formaldehyde in a molar ratio of two moles of formaldehyde to one mole melamine and containing hydroxyoxaalkylmelamines and, optionally, other additives in small amounts.
The present invention also includes a process for improving the comfort of fabrics made from melamine fibers by submerging the fabrics in an aqueous bath at a temperature and for a time such that the moisture regain of the melamine fiber in the fabric after said submerging is greater than about 6.5% by weight and preferably greater than about 7% by weight.
Another aspect of the present invention is a fabric comprising melamine fibers having a moisture regain of greater than about 6.5% by weight and preferably greater than at least about 7% by weight of the melamine fiber in the fabric. The fabric may be dyed. It may be composed of melamine fibers and other fibers.
Related objects and advantages of the present invention will be apparent to those of ordinary skill in the art after reading the following detailed description.
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Joseph, Marjory L. “Introductory Textile Science”, Fifth Edition, p. 335.
Burlone Dominick A.
Gadoury Dean R.
Johnson Karen L.
Kent George M.
BASF Corporation
Cole Elizabeth M.
Nixon & Vanderhye P.C.
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