Dye fixatives

Details Dye fixatives Dye fixatives

2001-03-15

2002-12-24

Einsmann, Margaret (Department: 1751)

Bleaching and dyeing; fluid treatment and chemical modification

Organic additive for dye composition, dye composition...

Ethylenimine or polymer thereof or polyalkylene polyamine

C008S552000, C008S557000, C008S566000, C008S576000

Reexamination Certificate

active

06497733

ABSTRACT:

FIELD OF THE INVENTION
The present invention is directed to the field of fiber and textile dyeing. More specifically, this invention relates to dye fixatives and their use in providing substantially permanent retention of dye color in textiles.
BACKGROUND OF THE INVENTION
Poor washfastness, that is, the leaching and bleeding of dye stuffs from fabrics, along with poor crockfastness, or the removal of dye from fabric when it is abraded, are two significant problems that to one degree or another must be overcome for any dyed good to be used commercially. Some loss of dye will take place from dyed textiles during washing and/or abrasion with all categories of dyes, including sulfur dyes, direct dyes, and vat dyes, e.g., indigo.
A number of coatings or reagents have been developed to improve the fastness properties of dyed textiles. For example, for direct dyes copper aftertreatments and diazotization/coupling have been used to improve fastness. However, the copper (II) ion that is employed in copper aftertreatments is not environmentally friendly, and diazotization requires chemical reactions to be performed on the absorbed dyes in the fibers. For vat dyes, fastness may be improved by soaping (that is, a treatment with a hot aqueous solution of a surfactant), which causes the dye molecules to rearrange and crystallize. Soaping may, however, substantially change the shade of the dyed good and the process can be time-consuming.
SUMMARY OF THE INVENTION
This invention is directed to treatments for dyed textile goods that will improve their fastness properties. More particularly, the invention is directed to certain fixatives that, when placed on the dyed textile, allow the dye to be permanently or substantially permanently affixed to the fabric. The dye-reactive fixative comprises a water-soluble or water-dispersible polymer or oligomer having reactive groups that react with a dye on a dyed web to affix the dye to the web. The dye-reactive fixative, in one embodiment, comprises a polyethylene glycol (PEG) polymer or oligomer that is terminally capped with glycidyl groups or with oxirane rings in other forms, such as epoxycyclohexyl groups. In another embodiment, the dye fixative comprises a mixture of functionalized or unfunctionalized PEG and poly(butadiene), preferably maleinized polybutadiene. In a further embodiment, the dye-reactive fixative comprises a silicone that is terminally capped with epoxide groups or with groups that form anhydrides.
The invention is further directed to the process for treating dyed textiles and other webs with a dye-reactive fixative preparation, wherein the fixative compound or mixture is applied to the fiber, yarn, textile, or other web. In a presently preferred embodiment, the dyed web is placed into the fixative preparation (dipped), then padded and dried in a single continuous process.
This invention is further directed to the dyed fibers, yarns, fabrics, textiles, finished goods, or nonwovens (encompassed herein under the terms “textiles” and “webs”) treated with the dye-reactive fixative preparation. Such textiles and webs exhibit a greatly improved colorfastness and resistance to fading, even after multiple launderings.
DETAILED DESCRIPTION OF THE INVENTION
The dye-reactive fixative preparation of the invention comprises, in one embodiment, a glycidyl- or other oxirane-containing polyethylene glycol (PEG) polymer or oligomer. Without being bound by theory, it is believed that the PEG fixative preparation covalently binds to the dye. These dye-reactive PEG preparations provide improved colorfastness and retention of the dye on the textile or web fiber structure.
In one presently preferred embodiment, the dye-reactive PEG fixative comprises a coating or finish composed of a polyethylene glycol (PEG) polymer or oligomer that is terminally capped with glycidyl groups. Other PEG derivatives that contain 1, 3, or more glycidyl groups are also possible, as are PEG oligomers and polymers that contain oxirane rings in other forms, such as epoxycyclohexyl groups. The PEG oligomers and polymers may contain from one ethylene glycol unit up to many thousands. Copolymers of ethylene glycol and propylene glycol that contain one or more oxirane moieties may also be employed. This invention is not limited to oxirane groups as reactive groups on PEG, or copolymers thereof. Reactive groups derived from cyanuric chloride or based on vinyl sulfones or anhydrides may also be used, as well as silicones with epoxide groups or with groups that form anhydrides. Additionally, N-methylol compounds including dimethylol dihydroxyethylene urea (DMDHEU), dimethylol urea (DMU), dimethylol ethylene urea (DMEU), formaldehyde, and the like can be used.
Without being bound by theory, it is believed that glycidyl groups on PEG react with sulfhydryl groups (—SH) (reactions 1a and 1b, below) in sulfur dyes, or with amines (reactions 2a and 2b, below) in other dyes, e.g., direct, vat, sulfur, acid, and disperse dyes. The PEG preparation will crosslink the dye molecules together. Sulfhydryl groups should be present on sulfur-dyed goods because of incomplete coupling to produce disulfides during dye application. The amine group, which is usually attached to an aromatic ring structure but may be aliphatic, is widely found in dye structures. Any crosslinking between dye molecules should increase the substantivity of the dyes in the textile, and a greater degree of crosslinking is to be expected if more than one nucleophilic group is present on the dye. Reactions with hydroxyl, carboxyl, or other nucleophilic groups on dyes may occur. It should also be possible for some oxirane groups to react with nucleophiles that are part of the fiber, such as hydroxyls, amines, carboxyls, sulfhydryls, etc. If such reactions do occur, they would also be expected to increase the substantivity of the dyes.
PEG and the reactive groups taught herein have a number of advantages. PEG is readily available, inexpensive, water-soluble or water-dispersible, and of low toxicity. It also has a low T
g
, which may help soften the hand of textiles to which it is applied. PEG that is endcapped with glycidyl groups is commercially available in a variety of molecular weights (from, for example, Aldrich) and is reasonably priced. PEG can also be derivatized with cyanuric chloride; the resultant compound can react with dyes and reactive textiles (e.g. cellulosics).
Another approach to improving colorfastness is to add polymeric “nets” to the dyed textile. These nets may react with the textiles and provide physical barriers preventing dye loss during washing. The nets may also chemically react with the dye, thus affixing the dyes to the fabric through chemical bonds. A preferred embodiment of this approach uses a combination of hyperbranched polyethylenimine (PEI) and solubilized chlorotriazines to form textile- and dye-reactive nets.
It should be recognized that seemingly small chemical changes on a dye structure can shift its absorption spectrum and, therefore, the shade on a fabric. For aromatic systems, the electron-donating capability of pendant groups increases in the following order: —OR, —OH, —NH
2
, —NHR, —NR
2
, where R is an alkyl group. Therefore, reactivity of an amine that is pendant on an aromatic system with a glycidyl group is expected to red-shift the absorption maximum of the dye, and similar reactivity of a hydroxyl group should blue-shift its absorption maximum.
Some possible reactions of diglycidyl-PEG with sulfhydryls and amines are illustrated below:
The present invention is further directed to the dyed fibers, yarns, fabrics, finished goods, or other textiles (encompassed herein under the terms “textiles” and “webs”) treated with the dye-reactive PEG fixative. These textiles or webs will display improved colorfastness and retention of the dye on the textile or web fiber structure, even after multiple launderings.
The colorfast webs of the present invention are intended to include fabrics and textiles, and may be a sheet-like structure (woven, knitted, tufted, stitch-bonded, or non-woven) compri

Affiliated with

Also associated with

Rating

Dye fixatives does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Dye fixatives, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dye fixatives will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2968203