Plastic and nonmetallic article shaping or treating: processes – With incorporating dye susceptible material or dyeing workpiece
Reexamination Certificate
2001-03-02
2003-02-25
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With incorporating dye susceptible material or dyeing workpiece
C008S494000, C008S531000, C008S924000, C028S247000, C057S287000, C264S103000
Reexamination Certificate
active
06524503
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the manufacture of polyamide yarns that improves the dyeing of melange cloth. More particularly, the invention relates to a process by which, garments made with these yarns can be dyed such that when knitted or woven into a fabric, a melange effect is obtained. The invention particularly relates to a single-step dyeing process.
BACKGROUND OF INVENTION
When two or more different types of yarn are knitted or woven together, the resulting garment is usually non-uniform in appearance. Such non-uniformity may be exploited to provide a pleasant and fashionable result. However, in order to do so, the yarn combination and dyeing have to be carefully designed. The production and the dyeing of cloths having multiple shades and colors are known in the textile industry. In order to achieve the multiple color effect, fabric can be knitted or woven either with pre-dyed yarns or with different types of natural (grege/gray) yarns, or with combinations thereof. In order to create the required multiple-color effect, the fabric can be further dyed with one or more dyestuffs, in a single or several dyeing steps. When these coloring effects occur in fine patterns, the resulting effect is known as “heather”, or “two-tone” or “melange”. A particular example of this melange group, are fabrics that have different shades and depths of the same basic color.
Among other methods known in the art, the following techniques are commonly used to achieve the melange effect in a single-step dyeing process:
a) Combination of two yarns each made from a different polymer. For example, one yarn is polyamide 6,6 and the other yarn is polyester. The two yarns, or the garment made from combining these yarns, can be dyed in a single-step process by using the same dyestuff. In this process, one yarn is selectively dyed by the Nylon dyestuff (e.g. Lanaset dyestuff by CIBA-GEIGY), while the other yarn is either partially dyed, or is not dyed, by the same dyestuff.
b) Combination of two yarns made from the same polymer (e.g. polyamide 6,6), but with different polymer characteristics. Such differences could be different cross-sections (e.g. one yarn is round, while the other is tri-lobal), or different levels of luster (e.g. one yarn is “bright” since in contains no de-lustering additives, while the other is “dull”, because it contains titanium dioxide or other de-lustering additives), or different DPF (denier per filament), etc.
These differences can lead to differential dyeing of the two yarns, and will result in the heather effect.
c) Combination of two or more yarns, wherein each yarn is dyed by a different dyestuff and colors in the same process. Each yarn is dyed selectively by the respective dyestuff to which it is reactive.
The above techniques suffer from several disadvantages, and particularly:
a) In the first technique, the polymer system is not all polyamide, and therefore the complete garment is not of the highest quality attainable when using only Nylon yarns. Also, when using a polyamide-compatible dye, the polyamide is dyed to the required color, while the other yarn may not be dyed at all, or may be imperfectly dyed. This may form a sharp contrast between the two yarns, leading to harsh color difference which may be unacceptable to fashion items.
b) Differences in de-lustering of the two yarns may result in mixed opacity of the garment. This may be a desired fashionable effect, but it will not render the required variation in color shades, since various levels of de-lustering hae only a small effect on the depth of color shades. This difference does not render the garment the expected “heather” appearance.
c) Combining yarns with different cross-sections has another fashionable effect, but it does not render the required variation in color shades. Yarns with triangular or rectangular cross-section are shiny, while yarns with round cross-section are dull. Combination of such yarns will affect the level of light reflection of the garment, but not the color and the color shades of the cloth.
d) Dyeing with a mixture of dyestuffs, is a complex process in which the dyestuff components may interact with one another, resulting in undesired effects.
The mechanism of Nylon dyeing has been thoroughly investigated and described in “Challenges in the Art and Science of Dyeing” AATCC symposium (No. 32), 1983. The rate of diffusion, hydrogen and ionic bonding of the dyestuff to the polymer and the dyeing mechanism have been reported.
Polyamide yarns have been dyed by two main dyestuff types: acid and disperse dyes. While the disperse dyes are substantially insensitive to the chemical composition of the polyamide molecule, the acid dyestuff, capable of forming anionic groups, may be chemically associated with the amine end-group of the polyamide molecular backbone. Even small changes in the amine end-groups content, may affect the uptake of the acid dyestuff by the yarn in the dyeing bath, and thus affect the depth of the dyeing and the color intensity of the garment. The process of controlling the dyeing depth of Nylon by acid dyestuff via variation in the amine end-group concentration is well known in the art. U.S. Pat. No. 3,511,815 teaches that by obtaining high amine-end group (120-150 meq/kg), the Nylon 6,6 exhibits increased dyeability.
U.S. Pat. No. 4,017,255 teaches a process for the manufacturing of fiber materials containing at least two groups of differentially dyed Nylon filaments, each having a different carboxyl end-group content.
U.S. Pat. No. 4,295,329 discloses a method for making a continuous filament heather dyeable yarn involving cobulking in a hot fluid jet process a first unbulked yarn with a second previously bulked yarn. This patent teaches the use of a first yarn which contains cationically sulfonate dye sites, and of a second yarn which is of regular or deep acid-dyeing capability. The process described in U.S. Pat. No. 4,295,329 is suitable in principle for the carpet trade. It is suitable for the preparation of heavy denier bulked yarns within the range of 1500-5000 total denier. In addition, this process is based on combining different lengths of yarns.
European patent application EP 409,093 teaches a method for reducing the number of amine end groups by reacting polyamide fibers and combining them with normal polyamide fibers, thus resulting in a two-tone yarn. This process is mainly useful for stainblocking in the carpet industry.
U.S. Pat. No. 4,059,949 teaches the production of heather yarns formed by a combination of two different polymers. JP 7070852 teaches the use of acrylic yarns with melange shades. KR 9411305 teaches the preparation of polyester yarns having a two-tone effect. This yarn is used to prepare shrinkable plastics.
Polyamide yarns made from Nylon 6,6, 6,9 and 6,10 can be used in the textile industry in both knitting and weaving with high efficiency to form high quality and fashionable garments. These polymers, especially Nylon 6,6 are used in the production of knitted leg-wear and body-wear garment. In these products, dyeing efficiency and cost effective dyeing processes are important considerations.
The present invention is a single-step dyeing process, and thus it is a cost-effective alternative to other known methods.
It is a purpose of the present invention to provide a method for chemically forming the various polyamides 6,6, 6,9, 6,10—based yarns of modified dyeability properties. These yarns can be combined in a texturing or in a draw twisting, or in a draw winding process into a double-ply yarn having the capacity of creating the fashionable melange effect following dyeing.
It is another purpose of this invention to provide a process to dye the combined (double-ply) yarn in a single-step and inexpensive process.
It is yet another object of the present invention to provide for the production of a quality garment having multiple shades of the same color (“heather effect”).
Other purposes and advantages of the invention will become apparent as the description proceeds.
SUMMARY OF INVENTION
The in
Afek Uri
Blutstein Martin
Gazit Samuel
Rotem Ran
Weiser Alon
Lerner David Littenberg Krumholz & Mentlik LLP
Nilit Ltd.
Tentoni Leo B.
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