Patent Application
20170275814
Coloration of a substrate is the process of applying dyes to color the substrate, for example, textile products such as fibers, yarns, and fabrics. Currently, textiles are placed in contact with a dyebath, which normally includes a delivery system, such as water, dyes, and chemical auxiliaries for improving the coloration process and the properties of the colored textile. The dye is incorporated into or onto the textile fabric or fiber by chemical reaction, absorption, dispersion, or adhesion.
Different classes of dyes are used for different types of fiber and at different stages of textile production. For example, basic dyes are used to dye acrylic fibers, acid dyes are used to dye nylon and protein fibers such as wool and silk, disperse dyes are used to dye polyester fiber, and vat dyes, reactive dyes, and direct dyes are used to dye cotton.
High purity water is required for the color process, with water exiting the textile dyeing process containing as many as 72 toxic chemicals, many of which cannot be filtered or easily removed. According to the U.S. Environmental Protection Agency, an average of 40 liters of water is required for dyeing 1 kg of cloth, changing according to the textile and dyeing process.
One embodiment of the present method for coloring a substrate, as embodied and broadly described herein, includes: attaching a plasma-polymerizable moiety to a functional group of a dye capable of receiving the moiety, forming thereby a plasma-polymerizable dye; depositing the plasma-polymerizable dye on at least one surface of the substrate, forming thereby a plasma-polymerizable dye-coated substrate; and exposing the at least one surface of the plasma-polymerizable dye-coated substrate to a plasma.
Another embodiment of the present method for coloring a substrate, includes: attaching a plasma-polymerizable moiety to a functional group of a dye capable of receiving the moiety, forming thereby a plasma-polymerizable dye; dissolving the plasma-polymerizable dye in a nonaqueous solvent therefor, forming a solution; atomizing the solution of the plasma-polymerizable dye onto at least one surface of the substrate, forming thereby a plasma-polymerizable dye-coated substrate; exposing the at least one surface of the plasma-polymerizable dye-coated substrate to an atmospheric pressure plasma; and removing unpolymerized plasma-polymerizable dye from the substrate.
Yet another embodiment of the present method for coloring a substrate, includes: attaching a plasma-polymerizable moiety to a functional group of a dye capable of receiving the moiety, forming thereby a plasma-polymerizable dye; preparing a dispersion of the plasma-polymerizable dye in a nonaqueous liquid; atomizing the dispersion of the plasma-polymerizable dye onto at least one surface of the substrate, forming thereby a plasma-polymerizable dye-coated substrate; exposing the at least one surface of the plasma-polymerizable dye-coated substrate to an atmospheric pressure plasma; and removing unpolymerized plasma-polymerizable dye from the substrate.
Benefits and advantages of embodiments of the present invention include, but are not limited to, providing a method for dyeing substrates, such as fabrics, using an atmospheric pressure plasma and polymerizable moieties chemically bonded to various dyes, without requiring water or heat.
Briefly, embodiments of the present invention include coloration of substrates, including textiles, by plasma polymerization of dyes to which polymerizable moieties have been chemically bonded at sites on the dye capable of bonding to such moieties, that have been deposited on at least one surface of the substrate. Atmospheric pressure plasmas were used for the polymerization process, although sub-atmospheric pressure plasmas are expected to be effective for some systems. Generally, the plasma polymerization is performed away from the dye deposition so that undeposited dye is not exposed to the plasma.
Textiles may include cotton, polyester, wool, silk, acrylics, polypropylene, polyolefins, aramids, and nylon, and blends thereof. The plasma-polymerizable moiety may be chosen from acrylates, methacrylates, and vinyl amides. Dye functional groups may include hydroxyl groups, carboxyl groups, amines: primary, secondary, and tertiary, epoxides, carboxylic adds, and chlorides, and dyes may include add dyes, disperse dyes, azo dyes, vat dyes, sulfur dyes, direct dyes, reactive dyes, basic dyes, pigment dyes, aniline dyes, anthraquinone dyes, and coumarin dyes, as examples.
As an example of this process, an acrylate moiety can be formed by reacting starting compounds such as
with the hydrogen at the site of the secondary amine for disperse dye, Disperse Red 9,
to form:
respectively.
The acrylamides:
may also be utilized.
R groups may include no or one or more carbon atoms in linear or branched configurations, as examples, and mare complex groups may be used to provide additional functionality, such as flame retardancy, antimicrobial functions, water/oil repellency, etc. When reacted with a dye molecule, the new compound might have multiple functionalities (for example, color and flame retardancy). Other methods for achieving additional functionality will be discussed below.
An example of a dye having an accessible carboxylic add is Coumarin 343.
Examples of dyes having available hydroxyl groups are disperse dyes, such as Disperse Yellow 1, and azo dyes, such as Allura Red,
The plasma-polymerizable moieties are covalently bonded to the dye. An auxochrome is a functional group of atoms having nonbonded electrons, which when attached to a chromophore, alters both the wavelength and intensity of absorption. If these groups are in direct conjugation with the pi-system of the chromophore, they may increase the wavelength at which the light is absorbed and, as a result, intensify the absorption. A feature of these auxochromes is the presence of at least one lone pair of electrons which can be viewed as extending the conjugated system by resonance. As stated above, acrylate moieties can bond to hydroxyl, carboxylic acid, and amines. A bathochromic shift (effect) is a shift of a spectral band to lower frequencies (longer wavelengths, or red shift) owing to the influence of substitution or a change in environment. When changing the auxochrome, a wavelength shift can occur. For example, changing the primary amine to a secondary amine will cause a bathochromic shift of about 60 nm, while changing an alcohol group to an ether causes a bathochromic shift of about 6 nm. Replacing the hydrogen with an acrylate moiety on carboxylic acid group of a dye should not cause a shift in wavelength. Once the plasma-polymerizable dye is synthesized, its color can be determined and catalogued for use.
It is anticipated by the present inventors that various compositions may be mixed with the plasma-polymerizable dye to impart additional functionality to the substrate coating such as wicking properties, antimicrobial behavior, water repellency and flame retardance, as examples. The mixture of chemicals, including the plasma-polymerizable dye, would be applied to the substrate, and plasma cured. In the event that the materials do not mix well, they might be applied one at a time before the curing process.
For antimicrobial functionality, 2,4-dicholorophenyl acrylate, (3 acrylamidopropyl)trimethylammonium chloride, 4-(2-thiocyanato-3-acryl propionyloxy) butyl acrylates, and Diallyldimethyl ammonium chloride, as examples, may be used individually, or in various combinations.
As wicking/hydrophilic agents, Di(ethylene glycol) acrylates, and Glycerol 1,3 dicglycerolate diacrylate may be used individually, or in various combinations.
Fluorinated and non-fluorinated water repellent compounds may include Stearyl acrylate, Lauryl acrylate, Behenyl acrylate, Perfluorinated acrylates, and Silicone acrylates, individually and in various combinations.
For flame retardants, 2,3,4,5,6-pentabromobenzyl acrylate, Phosphate acrylates, Phosphonium acrylates, and Phosphonate acrylates, as examples, may be used individually or in combination.
Having generally described the present invention, the following EXAMPLES are set forth to provide additional details.
In what follows, the atmospheric plasma apparatus described in U.S. Patent Application Publication No. US 2014/0076861 A1, for “Atmospheric-Pressure Plasma Processing Apparatus And Method,” by Carrie E. Cornelius et al., Published on Mar. 20, 2014, was utilized. Typical process conditions for plasma dyeing in a roll-to-roll system in accordance with the teachings of embodiments of the present invention, include:
In order to test the ability of atmospheric pressure plasma to dye fabric, plasma-polymerizable dyes were synthesized and applied to three fabrics: nylon, cotton, and polyester. The dye was dissolved in a nonaqueous solvent, which may include alcohols, acetates, ketones, alkyl benzenes, alkanes, and glycols, and combinations thereof, with similar compositions for the nonaqueous liquids, and applied to both sides of the fabric using atomizing nozzles. The fabric was then passed through the atmospheric pressure plasma apparatus described above, and plasma treated to polymerize and bind the dye to the fabric. Control fabric samples were sprayed with dye but not exposed to plasma. The efficacy of plasma dyeing was tested by extracting dyed fabric treated with and without plasma using Soxhlet extractors and solvents, which may include alcohols, acetates, ketones, alkyl benzenes, alkanes, and glycols, and combinations thereof.
Three fabric types were selected for dyeing, a 100% polyester poplin, 100% plain-weave cotton and 100% rip-stop nylon fabric, as shown in the TABLE. All fabrics were obtained from Test Fabrics and contained no dye or finish.
Three plasma-polymerizable dyes with two different plasma-polymerizable groups were evaluated. The plasma-polymerizable groups are circled.
Plasma-curable Dye Synthesized from Pre-curser Dye Disperse Orange 3
Color: Yellow/Orange. Shift in color occurs towards yellow, due to the bathochromatic shift.
Plasma-curable Dye Synthesized from Pre-curser Dye Disperse Red 17
Plasma-curable Dye Synthesized from Pre-curser Dye Disperse Black 9
Color: Yellow. Shift in color occurs to yellow, due to the bathochromatic shift.
After application of the dye and plasma treatment, samples were washed in solvent to remove any dye contaminant incapable of plasma-polymerization, and any unreacted dye monomer. As an example, samples were washed using Soxhlet extraction with 99.9% Isopropanol (Sigma Aldrich), Samples were extracted until all dye was removed, as evidenced by the extraction liquid remaining clear for a minimum of two washing steps.
All samples sprayed with dyes changed colors, but only the samples that were treated with plasma retained coloration after the solvent extraction. The cotton, nylon, and polyester fabrics were successfully dyed by all three plasma-polymerizable dye compounds. In addition, both plasma-polymerizable groups were shown to be capable of polymerization by plasma.
The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
The present application claims the benefit of U.S. Provisional Patent Application No. 62/312,685 for “Method For Coloring A Substrate Using Atmospheric Pressure Plasma Polymerization” by Carrie E. Cornelius and James B. McNeill III, which was filed on 24 Mar., 2016, the entire content of which patent application is hereby specifically incorporated by reference herein for all that it discloses and teaches.
| Number | Date | Country | |
|---|---|---|---|
| 62312685 | Mar 2016 | US |
