Patent Application
20120246842
The present development relates to the dyeing of textile fibers, particularly cellulosic fibers and especially cotton fibers, with disperse dyes.
As a matter of past practice, cotton fibers in the form of yarns and fabrics have generally been dyed with reactive, direct, sulfur, vat, indigo or mordant dyes. Currently the industry prefers reactive dyeing for apparel as reactive dyes provide the brightest colored cotton of all the dyes. Water-soluble reactive dyes, which also provide dyeing results with good fastness-to-washing properties, can be used to dye or print hydrophilic cellulose fibers such as cotton fibers. In such procedures, the cellulose fiber —OH groups which are accessible on the fiber surface react with the fiber- reactive groups of the reactive dyes, forming a covalent fiber/dye bond.
Direct or substantive dyes are used in a neutral or slightly alkaline dye bath with the addition of sodium chloride or sodium sulfate. Vat dyes such as indigo are essentially insoluble in water. Reduction in alkaline liquor produces the water soluble alkali metal salt of a vat dye, which salt has an affinity for textile fibers such as cotton. Both direct and vat dyes provide for dull shades which limits their ability to expand into all cotton dyeing applications.
Dyeing of cotton with reactive dyes gives good color fastness. However, reactive dyes are strongly hydrophilic leading to dye wastage and process inefficiencies and high costs due to the necessity of using long dyeing times with salt additions and alkali, thus allowing for the sensitive needs of reactives for high pH and high temperature conditions. Reactive dyes which do not react with cotton cellulose in the dyeing step eventually react with water and hydrolyze. This hydrolyzed dye must be removed from the cotton surface after dyeing with an after-soaping step to improve crockfastness and washfastness properties. Reactive dyes are also currently under scrutiny as possibly being cancer-causing agents.
Another dye class commonly employed for the coloring of textiles comprises disperse dyes. Disperse dyes were originally developed for the dyeing of cellulose acetate and are water-insoluble. Disperse dyes are finely ground in the presence of a dispersing agent. The main use of disperse dyes is for the dyeing of polyester, but they can also be used to dye nylon, cellulose acetate and acrylic fibers. Dyeing of polyester with disperse dyes requires a temperature of 130° C. provided through an exhaust (batch) machine capable of high pressure (such as a jet machine) or a continuous process with a stenter frame (See Thermasol process).
Given their lack of affinity or substantivity for cellulose, disperse dyes cannot be readily used to dye cotton fibers and fabrics. However, some attempts have been made to provide procedures for dyeing modified cotton fibers, e.g., fabrics, with disperse dyes. For example, U.S. Patent Publication No. 2006/0048308 discloses a method of dyeing or printing cellulose-containing fiber materials using disperse dyes. Such a method comprises pre-treating the cellulose fiber material with a water-soluble or dispersible polyester resin and a water-soluble or dispersible acrylic binder. The polyester resin is fixed, for example, to cotton fabric with the acrylic binder and strong cross-linkers (e.g., melamine) via a pretreatment bath. The polyester impregnated fabric is then dyed with an aqueous dye bath containing disperse dye at a temperature of 130° C. under elevated pressure conditions. However, the high levels of resin binder required in this process adversely affects the softness of the dyed fabric.
Notwithstanding the foregoing procedures for dyeing hydrophilic fibers and fabrics using reactive, direct, vat or water-insoluble disperse dyes, it would be advantageous to provide additional techniques for dyeing cotton and other cellulosic fibers and fabrics using disperse dyes under relatively mild dyeing conditions to produce full package dyed cotton fabrics and garments which have especially desirable softness, color fastness and light fastness and which also have a tendency for shorter post dyeing finishing treatment process times. Such finished dyed cotton fibers and fabrics would then be especially useful for preparation of textured, high-end garments such as those produced by further fabric and garment treatment such as stone-washing.
In one aspect, the present development is directed to a dyed fibrous material comprising a plurality of textile fibers and a polymer bonded to the fibers and to a disperse dye material to affix the dye material to the fibrous material.
Conveniently, the textile fibers comprise natural fibers, preferably cellulosic fibers, more preferably cotton fibers, optionally together with synthetic fibers.
In one embodiment, the polymer is a dried and/or cured emulsion polymer, which preferably contains less than 25 wt %, more preferably less than 10 wt %, of a polyester, and most preferably contains substantially no polyester.
In a further aspect, the present development is directed to a dyed cotton fibrous material comprising a plurality of cotton fibers, a cellulose-reactive emulsion copolymer which has been contacted with said fibers being chemically bonded to said fibers by curing the cellulose-reactive emulsion copolymer to effect reaction of said emulsion copolymer at least partially with cellulose hydroxyl moieties within said cotton fibers, with a disperse dye material being affixed to said fiber-bonded emulsion copolymer.
Typically, the emulsion copolymer is selected from vinyl ester-based, acrylic-based, styrene/acrylic-based or styrene/butadiene-based emulsion copolymers.
In one embodiment, the emulsion copolymer is a vinyl ester-based copolymer selected from vinyl acetate-ethylene copolymers, vinyl acetate-vinyl alkanoate; vinyl acetate-acrylic copolymers, and combinations of said copolymer types and preferably is a vinyl acetate-ethylene copolymer comprising from about 60 wt % to about 95 wt % of vinyl acetate and from about 5 wt % to about 50 wt % of ethylene, based on total monomers used to produce the polymer.
In a further embodiment, the emulsion copolymer is an acrylic emulsion copolymer produced from a monomer mixture comprising at least two different (meth)acrylate monomers, preferably ethyl acrylate and butyl acrylate.
Conveniently, the disperse dye is selected from carboxylic acid group-free and sulfonic acid group-free nitro, amino, aminoketone, ketoninime, methine, polymethine, diphenylamine, quinoline, benzimidazole, xanthene, oxazine, coumarin, anthraquinone and azo dyes.
In one embodiment, the plurality of textile fibers form at least part of a fabric or a garment, such as a shirt.
In yet a further aspect, the present development is directed to a process for dyeing textile fibers, the process comprising:
In still yet a further aspect, the present development is directed to a process for dyeing textile fibers, the process comprising:
Conveniently, the contacting of the fibers with the emulsion polymer and the subsequent drying/curing of the emulsion polymer are carried out in the substantial absence of non-fibrous polyester compounds which have ester linkages in their polymer backbone.
Generally, B) is carried out by subjecting said polymer to a temperature of from about 105° C. to about 170° C., preferably from about 140° C. to about 165° C.
The present development is directed to the dyeing of textile fibers in the form of a yarn, fabric or garment, using a polymer binder, typically a dried and/or cured emulsion copolymer, which directly bonds to the fibers and to a disperse dye material so as to affix the dye to the fibers. In this way, even when the fibers are formed mostly or totally of a cellulosic material, such as cotton, a wash fast and light fast dyed product can be produced without sacrificing the softness of the underlying fibers.:
The term “textile fibers” is used herein to individual staple fibers or filaments (continuous fibers), yarns, fabrics, and articles (e.g., garments). Yarns may include, for instance, multiple staple fibers that are twisted together (“spun yarn”), filaments laid together without twist (“zero-twist yarn”), filaments laid together with a degree of twist, and a single filament with or without twist (“monofilament”). The yarn may or may not be texturized. Suitable fabrics may likewise include, for instance, woven fabrics, knit fabrics, and non-woven fabrics. Garments may be apparel and industrial garments. The terms “fabrics” and “textiles” also include home goods such as linens, drapery, and upholstery (automotive, boating, airline included) made of the cotton fibrous materials described herein.
Any type of textile fiber can be used with the present dyeing process but the process is particularly applicable to natural fibers, such as cotton, wool, bast, silk, etc., especially cellulosic fibers and most particularly cotton fibers. In some cases it may be desirable to employ a combination of natural fibers with synthetic fibers, such as aromatic polyamides (e.g., meta-aramids (e.g., Nomex® or Kevlar®), para-aramids, etc.), aliphatic polyamides (e.g., nylon), polyesters, polybenzimidazole (“PBI”), polybenzoxazole (“PBO”), polypyridobisimidazole (“PIPD”), rayon, melamine, acrylic (acrylonitrile) , acetate, lyocell, etc., as well as combinations of two or more types of natural and/or synthetic fibers. In general, it is preferred that the textile fibers employed herein contain at least 25 wt %, such as at least 50 wt %, for example at least 60 wt % of cotton fibers.
Prior to dyeing, the textile fibers materials are contacted and treated with a polymer capable of acting as a binder between the fibers and a disperse dye material. Generally, suitable polymers are emulsion copolymers and particularly cellulose-reactive aqueous emulsion copolymers, include those which have conventionally been used as textile finishing agents. Such emulsion copolymers include those described in detail in U.S. Patent Publication No. 2011/0005008. This '008 patent document is incorporated by reference herein in its entirety.
Suitable types of cellulose-reactive emulsion copolymers for use in the present method herein include vinyl ester-based, acrylic-based, styrene/acrylic-based and styrene/butadiene-based emulsion copolymers. Such copolymers typically can also contain minor amounts of cross-linking or emulsion stabilizing co-monomers. Such co-monomers can, for example, in and of themselves or in combination with external cross-linking agents, make the emulsion copolymers used herein cellulose-reactive. Other potentially useful polymers are water-based polyurethanes, aqueous fluoropolymer emulsions, water-based alkyd resins and aqueous emulsions of halogenated polymers (e.g., vinyl chloride, vinylidene chloride, chloroprene, chlorostyrene, etc.).
One preferred type of emulsion copolymer comprises the vinyl ester-based copolymers selected from vinyl acetate-ethylene copolymers, vinyl acetate-vinyl alkanoate copolymers; vinyl acetate-acrylic copolymers, and combinations of these copolymer types. Vinyl acetate-ethylene (VAE) emulsion copolymers are well-known. Such VAE copolymers useful herein can comprise from about 60 wt % to about 95 wt % of vinyl acetate and from about 5 wt % to about 50 wt % of ethylene, based on total monomers therein. More preferably, VAE copolymers will comprise from about 70 wt % to about 90 wt % of vinyl acetate and from about 8 wt % to about 15 wt % of ethylene, based on total monomers therein.
Another preferred type of emulsion copolymer for use in the method herein comprises acrylic emulsion copolymers made of acrylic ester co-monomers. The alkyl acrylates that can be used to prepare the acrylic ester copolymer emulsions include alkyl acrylates and alkyl methacrylates containing 1 to 12, preferably 1 to 10 carbon atoms in the alkyl group. The polymer backbone in the acrylic ester copolymer can be either hydrophilic or hydrophobic and it can comprise polymerized soft monomers and/or hard monomers. The soft and hard monomers are monomers which, when polymerized, produce soft or hard polymers, or polymers in between. Preferred soft acrylic ester monomers are selected from alkyl acrylates containing 2 to 8 carbon atoms in the alkyl group and include ethyl acrylate, propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. The hard acrylic ester monomers are selected from alkyl methacrylates containing up to 3 carbon atoms in the alkyl group and from non-acrylic monomers such as styrene and substituted styrenes, acrylonitrile, vinylchloride, and generally any compatible monomer the homopolymer of which has a Tg above 50° C. Preferred acrylic ester monomers are selected from alkyl acrylates and methacrylates containing 1 to 12 carbon atoms in the alkyl group, especially ethyl acrylate and butyl acrylate.
The polymer binder will frequently contain, in addition to the main monomers, minor amounts of co-monomers which can provide cross-linking with both cellulose hydroxyl moieties within the cotton fibers and cross-linking within the polymer itself. Such cross-linking co-monomers are unsaturated so as to polymerize into the polymer backbone and will also contain at least one functional group such as nitrogen, oxygen and/or silicon atoms.
Thus the polymer binder used herein can comprise from about 0.1 wt % to about 10 wt %, such as from about 0.5 wt. % to about 8 wt. %, for example from about 1 wt. % to about 6 wt. %, based on total monomers in the polymer, of one or more ethylenically unsaturated cross-linking co-monomers having, for example, at least one amide, epoxy, or alkoxysilane group. Specific examples of such co-monomers include, for instance, acrylamides, such as N-methylolacrylamide (NMA), N-methylolmethacrylamide, diacetoneacrylamide, etc., as well as esters or ethers thereof, such as isobutoxy ethers or esters of N-methylolacrylamide, of N-methylolmethacrylamide. Also suitable are epoxide-functional co-monomers, such as glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, vinyl glycidyl ether, etc. Further examples are silicon-functional co-monomers, such as acryloxy-propyltri(alkoxy)silanes and methacryloxy-propyltri(alkoxy)silanes, vinyltrialkoxysilanes and vinylmethyldialkoxysilanes, with alkoxy groups which can be present being, for example, methoxy, ethoxy and ethoxypropylene glycol ether radicals. Yet other suitable crosslinking co-monomers have hydroxy and/or carboxyl groups, such as hydroxyalkyl methacrylates and acrylates (e.g., hydroxyethyl, hydroxypropyl or hydroxybutyl acrylate or methacrylate), acetylacetoxyethyl acrylate or methacrylate, dimethylaminoethyl acrylate, etc.
The polymer binder can also contain, in addition to the main monomers and self cross-linking co-monomers, minor amounts of multifunctional external cross-linking co-monomers. Thus the copolymers used herein can optionally comprise from about 0.1 wt % to about 10 wt %, based on total monomers in the copolymer, of one of more of these multifunctional cross-linking co-monomers. Suitable external crosslinking agents may also include phenol formaldehyde resins, resorcinol formaldehyde resins, melamine formaldehyde resins, hydroxymethylsubstituted imidazolidinones or thioimidazolidinones, hydroxymethyl substituted pyrimidinones or hydroxymethyl substituted triazinones or glycoluriles or their self-condensation products are suitable or mixed condensates from two or more of the compounds mentioned, or a mixture from two or more of the compounds mentioned. When employed, such crosslinking agents are typically combined with the polymer after it is formed.
The polymer binders used herein to modify textile fibers materials prior to dyeing can frequently be selected from commercially available aqueous copolymer emulsions. Alternatively, suitable cellulose-reactive emulsion copolymers can be prepared in conventional fashion using known emulsion polymerization techniques and raw materials. In general, such emulsion copolymers can be prepared by polymerizing appropriate co-monomers in appropriate amounts in an aqueous reaction mixture using conventional polymerization initiators and catalysts and conventional polymerization conditions. Suitable polymerization processes are described in the Kirk-Othmer Encyclopedia of Chemical Technology, 4th Ed Vol. 24, pp. 954-963 (Wiley 1996). The copolymer emulsions so prepared can be stabilized with conventional emulsifiers (surfactants) and/or protective colloids.
In certain embodiments, light stabilizers can also be employed in the polymer binder to help improve the lightfastness of a dye that is applied to the fibers. Without intending to be limited by theory, it is believed that when crosslinked, the emulsion copolymer coating can help disperse and encapsulate the light stabilizer around the fiber so that it is not easily removed or degraded. When employed, light stabilizers may constitute from about 0.1 wt. % to about 10 wt. %, in some embodiments from about 0.2 wt. % to about 5 wt. %, and in some embodiments, from about 0.25 wt. % to about 4 wt. % of the polymer coating.
One particularly suitable light stabilizer that may be employed is a hindered amine light stabilizer (“HALS”). Suitable HALS compounds may be derived from a substituted piperidine, such as alkyl-substituted piperidyl, piperidinyl, piperazinone, alkoxypiperidinyl compounds, and so forth. For example, the hindered amine may be derived from a 2,2,6,6-tetraalkylpiperidinyl. The hindered amine may, for example, be an oligomeric or polymeric compound having a number average molecular weight of about 1,000 or more, in some embodiments from about 1000 to about 20,000, in some embodiments from about 1500 to about 15,000, and in some embodiments, from about 2000 to about 5000. Such compounds typically contain at least one 2,2,6,6-tetraalkylpiperidinyl group (e.g., 1 to 4) per polymer repeating unit. One particularly suitable high molecular weight hindered amine is commercially available from Clariant under the designation Hostavin® N30 (number average molecular weight of 1200). Another suitable high molecular weight hindered amine is commercially available from Adeka Palmarole SAS under the designation ADK STAB® LA-63 and ADK STAB® LA-68. Yet other examples of suitable high molecular weight hindered amines include, for instance, an oligomer of N-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol and succinic acid (Tinuvin® 622 from Ciba Specialty Chemicals, MW=4000); oligomer of cyanuric acid and N,N-di(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylene diamine; poly((6-morpholine-S -triazine-2,4-diyl) (2,2,6,6-tetramethyl-4-piperidinyl)-iminohexamethylene-(2,2,6,6-tetramethyl-4-piperidinyl)-imino) (Cyasorb® UV 3346 from Cytec, MW=1600); polymethylpropyl-3-oxy-[4(2,2,6,6-tetramethyl)-piperidinyl)-siloxane (Uvasil® 299 from Great Lakes Chemical, MW=1100 to 2500); copolymer of α-methylstyrene-N-(2,2,6,6-tetramethyl-4-piperidinyl)maleimide and N-stearyl maleimide; 2,4,8,10-tetraoxaspiro [5.5] undecane-3,9-diethanol tetramethyl-polymer with 1,2,3,4-butanetetracarboxylic acid; and so forth. Still other suitable high molecular weight hindered amines are described in U.S. Pat. Nos. 5,679,733 to Malik, et al. and U.S. Pat. No. 6,414,155 to Sassi, et al.
In addition to the high molecular hindered amines, low molecular weight hindered amines may also be employed. Such hindered amines are generally monomeric in nature and have a molecular weight of about 1000 or less, in some embodiments from about 155 to about 800, and in some embodiments, from about 300 to about 800. Specific examples of such low molecular weight hindered amines may include, for instance, bis-(2,2,6,6-tetramethyl-4-piperidyl) sebacate (Tinuvin® 770 from Ciba Specialty Chemicals, MW=481); bis-(1,2,2,6,6-pentamethyl-4-piperidinyl)-(3,5-ditert.butyl-4-hydroxybenzyl)butyl-propane dioate; bis-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate; 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro-(4,5)-decane-2,4-dione; butanedioic acid-bis-(2,2,6,6-tetramethyl-4-piperidinyl) ester; tetrakis-(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane tetracarboxylate; 7-oxa-3,20-diazadispiro(5.1.11.2) heneicosan-20-propanoic acid, 2,2,4,4-tetramethyl-21-oxo, dodecyl ester; N-(2,2,6,6-tetramethyl-4-piperidinyl)-N′-amino-oxamide; o-t-amyl-o-(1,2,2,6,6-pentamethyl-4-piperidinyl)-monoperoxi-carbonate; β-alanine, N-(2,2,6,6-tetramethyl-4-piperidinyl), dodecylester; ethanediamide, N-(1-acetyl-2,2,6,6-tetramethylpiperidinyl)-N′-dodecyl; 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl)-pyrrolidin-2,5-dione; 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidinyl)-pyrrolidin-2,5-dione; 3-dodecyl-1-(1-acetyl,2,2,6,6-tetramethyl-4-piperidinyl)-pyrrolidin-2,5-dione; (Sanduvar® 3058 from Clariant, MW=448.7); 4-benzoyloxy-2,2,6,6-tetramethylpiperidine; 1-[2-(3,5-di-tert-butyl-4-hydroxyphenylpropionyloxy)ethyl]-4-(3,5-di-tert-butyl-4-hydroxylphenyl propionyloxy)-2,2,6,6-tetramethyl-piperidine; 2-methyl-2-(2″,2″,6″,6″-tetramethyl-4″-piperidinylamino)-N-(2′,2′,6′,6′-tetra-methyl-4′-piperidinyl) propionylamide; 1,2-bis-(3,3,5,5-tetramethyl-2-oxo-piperazinyl) ethane; 4-oleoyloxy-2,2,6,6-tetramethylpiperidine; and combinations thereof. Other suitable low molecular weight hindered amines are described in U.S. Pat. No. 5,679,733 to Malik, et al.
Other suitable light stabilizers may include UV absorbers, such as benzotriazoles or benzopheones, which can absorb ultraviolet light energy. Suitable benzotriazoles may include, for instance, 2-(2-hydroxyphenyl)benzotriazoles, such as 2-(2-hydroxy-5-methylphenyl)benzotriazole; 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole (Cyasorb® UV 5411 from Cytec); 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzo-triazole; 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole; 2-(2-hydroxy-3,5-dicumylphenyl)benzotriazole; 2,2′-methylenebis(4-tert-octyl-6-benzo-triazolylphenol); polyethylene glycol ester of 2-(2-hydroxy-3-tert-butyl-5-carboxyphenyl)benzotriazole; 2-[2-hydroxy-3-(2-acryloyloxyethyl)-5-methylphenyl] -benzotriazole; 2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-butylphenyl]benzotriazole; 2-[2-hydroxy-3-(2-methacryloyloxyethyl)-5-tert-octylphenyl]benzotriazole; 2-[hydroxy-3-(2-methacryloyloxyethyl)-5-tert-butylphenyl]-5-chlorobenzotriazole; 2-[2-hydroxy-5-(2-methacryloyloxyethyl)phenyl]benzotriazole; 2-[2-hydroxy-3-tert-butyl-5-(2-methacryloyloxyethyl)phenyl]benzotriazole; 2-[2-hydroxy-3-tert-amyl-5-(2-methacryloyloxyethyl)phenyl]benzotriazole; 2-[2-hydroxy-3-tert-butyl-5-(3-methacryloyloxypropyl)phenyl]-5-chlorobenzotriazole; 2-[2-hydroxy-4-(2-methacryloyloxymethyl)phenyl]benzotriazole; 2-[2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropyl)phenyl]benzotriazole; 2-[2-hydroxy-4-(3-methacryloyl-oxypropyl)phenyl]benzotriazole; and combinations thereof. Exemplary benzophenone light stabilizers may likewise include 2-hydroxy-4-dodecyloxybenzophenone; 2,4-dihydroxybenzophenone; 2-(4-benzoyl-3-hydroxyphenoxy) ethyl acrylate (Cyasorb® UV 209 from Cytec); 2-hydroxy-4-n-octyloxy)benzophenone (Cyasorb® 531 from Cytec); 2,2′-dihydroxy-4-(octyloxy)benzophenone (Cyasorb® UV 314 from Cytec); hexadecyl-3,5-bis-tert-butyl-4-hydroxybenzoate (Cyasorb® UV 2908 from Cytec); 2,2′-thiobis(4-tert-octylphenolato)-n-butylamine nickel(II) (Cyasorb® UV 1084 from Cytec); 3,5-di-tert-butyl-4-hydroxybenzoic acid, (2,4-di-tert-butylphenyl) ester (Cyasorb® 712 from Cytec); 4,4′-dimethoxy-2,2′-dihydroxybenzophenone (Cyasorb® UV 12 from Cytec); and combinations thereof.
When employed, light stabilizers, emulsifiers, protective colloids, initiators, can be partly included in the initial charge and partly metered in, or metered in completely during the implementation of the polymerization. The metering may take place separately or together with at least one monomer in the form of a monomer emulsion. Residual monomer can also be removed following the end of the polymerization, using known methods, by postpolymerization, generally by means of postpolymerization initiated using redox systems. Volatile residual monomers may also be removed by means of distillation, typically under reduced pressure, and, where appropriate, with inert entraining gases such as air, nitrogen or steam passed through or over the product.
The resultant emulsion copolymer will typically possess a solids contents of from about 20 wt. % to about 70 wt. %, such as from about 40 wt. % to about 60 wt. % although, as discussed below, maybe diluted before being applied to the textile fibers. The pH of the emulsion will typically range from about 2 to about 8, such as from about 4 to about 7. The polymer typically has a glass transition temperature less than 70° C. so that the flexibility of the fibers is not substantially restricted. Moreover, the polymer also typically has a glass transition temperature of more than −50° C. to minimize tackiness. In some embodiments. Generally, the polymer has a glass transition temperature from about −30° C. to about +50° C., preferably from about −15° C. to about +30° C.
The polymers described above are used in dispersed form to contact, treat and chemically modify the textile fibers prior to the dyeing operation. Such a procedure first involves contacting the fibers and dispersed copolymer to prepare a fiber/copolymer combination. This fiber/copolymer combination is then dried or cured to bond the polymer to the fibers. In the case of cotton fibers, this typically involves chemically anchoring the polymer to the cotton fibers via reaction with the hydroxyl groups of the cellulose component of the cotton fibers.
The textile fibers herein can be contacted with the dispersed polymer by any suitable technique in order to form the fiber/copolymer combination. For example, such contact can involve treatment of cotton fibrous material with a treatment bath which can be made by diluting an aqueous emulsion copolymer dispersion to a solids content of from about 2.0 wt % to about 10 wt %, more preferably from about 3 wt % to about 6 wt %. Such treatment baths will also have a pH of from about 3 to about 7, more preferably from about 5 to about 7.
Yarn can be treated with saturating liquors (called “pad baths”) with a nip roll squeeze after each bath saturation. Yarn can also be treated in “package” form with the saturating liquor. Woven goods can be pad bath finished in continuous stenter (open width) frames or with batch processes such as, piece dyeing, jet, beck, jigger or paddle machines. Knit goods can be processed in the same machinery (both continuous and batch) as woven, just under different conditions. For garments, industrial garment washing machines may be used. Optional application methods include manual processes such as spraying or manual wet add-on techniques.
In one embodiment, cotton fabric can be contacted with the emulsion copolymer-containing treatment bath in a continuous padding operation run at a pad pressure of from about 0.3 bar to about 2.5 bar and at a pad speed of from about 0.25 to about 1 m/minute. More preferably, such a continuous padding operation can be run at a pad pressure of from about 0.9 bar to about 1.1 bar and at a pad speed of from about 0.3 to about 0.6 m/minute. (Commercial production speeds can be considerably higher, for example from about 10 to about 30 meters/minute.)
In another embodiment, the fiber/copolymer combination in the form of a textile may be formed by exhaustion processing; that is, batchwise, with the textile being immersed in dilute aqueous treatment bath containing the copolymer. In another embodiment, textiles can be treated on a continuous apparatus for immersion treating textiles, as is disclosed, for example, in U.S. Pat. No. 4,920,621, the disclosure of which is incorporated herein by reference.
Other suitable methods of applying the polymer to textile fibers include rolling, spraying and printing, including gravure printing, screen printing and transfer printing.
Regardless of the method of application selected, application and processing conditions should be selected such that the resultant fiber/copolymer combination contains from about 0.1 to about 10 wt %, preferably from about 1 to about 8 wt %, more preferably from about 3 wt % to about 6 wt %, of the polymer on a dry basis.
After the fiber/copolymer combination has been formed, this combination is subjected to drying and/or curing conditions which are effective to bond the polymer to the fibers. In the case of cotton fibers, the curing typically serves to chemically anchor the copolymer to the cotton fibrous material via reaction of the copolymer with at least a portion of the hydroxyl moieties of the cellulose component of the cotton fibers. Such chemical reaction can occur via a cross-linking mechanism with the cross-linkable co-monomers which will generally form part of the emulsion copolymer as hereinbefore described. Curing of the fiber/copolymer combination also will generally promote some self-cross-linking of the copolymer within the fibrous cotton materials as well.
Curing conditions for the fiber/copolymer combination will generally involve heating the combination to elevated temperatures of from about 105° C. to about 170° C. for a period (dwell time) of from about 0.2 to about 4 minutes. More preferably, the fiber/copolymer combination can be cured by using temperatures of from about 140° C. to about 165° C. for a period (dwell time) of from about 0.3 to about 1 minute. In addition to anchoring the copolymer to the textile fibers, curing of the fiber/copolymer combination will also generally serve to remove water from this combination. Thus curing of the fiber/copolymer combination can serve to partially or even substantially completely dry the fiber/copolymer combination prior to the dyeing step of the method herein.
It may in some cases be convenient to selectively cure the polymer on the textile fibers by varying the amount of heat applied to different areas of the polymer. This can, for example, occur where a polymer treated garment is hung in a drying oven to effect curing of the polymer. In such a case, the outside surface of the garment will tend to receive more heat than the internal surface of the garment thereby resulting in migration of the cured polymer towards the outside surface of the garment. On dyeing, such a garment would be expected to have more dye affixed to the outside surface of the garment and hence a higher reflectance on that surface.
Where drying alone is sufficient to bond the polymer to the textile fibers this is conveniently conducted at a temperature from about 100° C. to about 160° C. for a period from about 0.5 to about 5 minutes.
The treating of the textile fibers with the dispersed polymer and the subsequent drying/curing of the fiber/polymer combination serves to provide chemically modified, polymer-treated fibrous material. The polymer may be present on the fibers as a continuous coating, but more preferably is bonded to spaced areas of said fibrous material so as to define a non-continuous layer on said fibers. Such polymer-treated cotton fibers can then be dyed using the disperse dyes and dyeing conditions hereinafter described.
As noted above, some dyeing of cotton-containing yarns, fabrics and garments has in the past been carried out using disperse dyes in the presence of non-fibrous polyester resins, such as polyethylene terephthalate (PET). In contrast to such previous dyeing procedures, the polymer binder employed in the present process typically contains less than 25 wt %, preferably less than 10 wt %, of a polyester, and most preferably contains substantially no polyester.
The chemically modified, polymer-treated fibers as hereinbefore described are subjected to a dyeing operation which employs disperse dye material as a dyeing agent. Disperse dyes were originally developed for the dyeing of cellulose acetate and are water-insoluble. They are generally finely ground in the presence of a dispersing agent (surfactant) and are sold as a paste or spray-dried and sold as a powder.
Suitable disperse dyes for use in the dyeing method herein are those described under “Disperse Dyes” in the Colour Index, 3rd edition (3rd revision 1987 inclusive of Additions and Amendments up to No. 85). Such dyes include, for example, carboxylic acid group-free and/or sulfonic acid group-free nitro, amino, aminoketone, ketoninime, methine, polymethine, diphenylamine, quinoline, benzimidazole, xanthene, oxazine and coumarin dyes and especially anthraquinone and azo dyes, such as mono- or di-azo dyes. Such disperse dyes are also those described in detail in U.S. Patent Publication No. 2006/0048308. That '308 patent document, and especially its disclosure of the several structural formulas for disperse dye materials disclosed therein, is incorporated herein by reference.
Examples of commercially available primary red color disperse dyes include Disperse Red 60 (Intrasil Brilliant Red 2B 200%), Disperse Red 50 (Intrasil Scarlet 2GH), Disperse Red 146 (Intrasil Red BSF), Disperse Red 127 (Dianix Red BSE), Dianix Red ACE, Disperse Red 65 (Intrasil Red MG), Disperse Red 86 (Terasil Pink 2 GLA), Disperse Red 191 (Intrasil Pink SRL), Disperse Red 338 (Intrasil Red 4BY), Disperse Red 302 (Tetrasil Pink 3G), Disperse Red 13 (Intrasperse Bordeaux BA), Disperse Red 167 (Foron Rubine S-2GFL), and Disperse Violet 26 (Intrasil Violet FRL). Examples of commercially available primary blue color disperse dyes include Disperse Blue 60 (Terasil Blue BGE 200%), Disperse Blue 291 (Intrasil Blue MGS), Disperse Blue 118 (Terasil Blue GBT), Terasil Blue HLB, Dianix Blue ACE, Disperse Blue 87 (Intrasil Blue FGB), Disperse Blue 148 (Palnnil Dark blue 3RT), Disperse Blue 56 (Intrasil Blue FBL), and Disperse Blue 332 (Bafixan Turquoise 2 BL liq.). Examples of commercially available primary yellow color dyes include Disperse Yellow 64 (Disperite Yellow 3G 200%), Disperse Yellow 23 (Intrasil Yellow 5R), Palanil Yellow HM, Disperse Brown 19 (Dispersol Yellow D-7G), Disperse Orange 30 (Foron Yellow Brown S-2RFL), Disperse Orange 41 (Intrasil Orange 4RL), Disperse Orange 37 (Intrasil Dark Orange 3GH), Disperse Yellow 3, Disperse Orange 30, Disperse Yellow 42, Disperse Orange 89, Disperse Yellow 235, Disperse Orange 3, Disperse Yellow 54, Disperse Yellow 233 (Foron Yellow S-6GL),
The preferred types of disperse dye materials useful herein include the quinoline dyes, the anthraquinone dyes and the azo dyes. The dyeing method herein is equally useful with disperse dyes whether they are classified as high energy dyes, medium energy dyes or low energy dyes. Useful disperse dyes which can be used herein also include dyes which are especially formulated for to serve as automotive dyes, lightfast dyes or fluorescent dyes.
In accordance with the dyeing method herein, the disperse dye materials are contacted with the polymer-treated textile fibers under conditions which are sufficient to affix at least a portion of the contacted disperse dye material to the polymer-treated fibers.
Generally, the polymer-treated fibers are contacted with the disperse dye material by immersing the fibers in an dye liquor in the form of an aqueous dispersion of the disperse dye material. The aqueous dye liquor can contain, for example, from about 0.01 wt % to about 15 wt % of the disperse dye material. More preferably, the aqueous dye liquor can contain from about 0.5 wt % to about 5.0 wt % of the disperse dye material. The lower concentrations of the dye in the dye liquor are useful for tinting operations. Higher dye concentrations in the dye liquor, of course, produce dyed cotton fibers, yarns, fabrics and garments having more intense color.
The aqueous dye liquor will generally be contacted with the fibrous material to be dyed at temperatures of from about 65° C. to about 100° C., more preferably from about 80° C. to about 95° C. Under such dyeing liquor temperature conditions, it is possible to carry out the dyeing step of the method herein at atmospheric pressure. Dyeing liquor pH will generally range from about 2 to about 8, more preferably from about 3 to about 7.
The dyeing step of the method herein may be carried out using either batch or continuous operations. If a batch method is employed, the polymer-treated fibers can be contacted with the dye liquor for a period of from about 0.25 to about 3 hours, more preferably from about 0.5 to about 1.0 hour. In batch operation, a dye liquor to fiber ratio of from about 30:1 to about 3:1 can be used. More preferably, when the fibers are in fabric form, liquor to fabric ratios of from about 20:1 to about 8:1 can be employed.
The aqueous dying liquor can optionally contain various fiber and fabric treating adjuvants besides the disperse dye material. Such adjuvants can include, for example, optical brighteners, fabric softeners, antistatic agents, antibacterial agents, anti-wrinkling agents, ironing aids, flame-retardants, enzymes, UV stabilizers, anti-foaming agents, perfumes, and the like.
As noted, the dyed fibers produced by the dyeing method described herein can be in a wide variety the forms. The fibers can be in the form of single ply or multi-plied yarns. Cotton staple fibers which form such yarns typically range from about 1.0 to about 3.0 denier per filament (dpf) and have a staple length range of from about 8.0 cm.
Cotton yarns can be fashioned into cotton fabrics for dyeing in accordance with the method herein by any conventional technique. The dyeing method herein is compatible with cotton fabrics having a wide range of fabric basis weights. Cotton fabrics will typically have a basis weight ranging from about 0.2 to about 7.0 g/m2.
Weaving is a common method for making cotton yarn into cotton fabrics. The woven cotton fabrics which can be dyed in accordance with the dyeing method described herein include, for example, those of a basic weave, satin weave, twill weave, ripstop weave or basket weave.
Cotton yarns can also be knitted to provide as variety of knitted fabric types prior to being dyed in accordance with the dyeing method herein. Knitted cotton fabrics can be of the weft knit type, including double knits, jersey knits, rib knits or pique knits. Knit cotton fabrics may also be of the warp type, including tricot knits or raschel knits.
Yarns and fabrics can, of course, also be fashioned into end use products such as garments, apparel, upholstery, linens, etc. prior to being dyed in accordance with the dyeing method herein. No matter which form the dyed cotton fibers take, the dyeing method described herein will produce dyed cotton fibers and articles similar to those prepared by ring-dyeing techniques. In such dyeing, only the external surfaces of the copolymer-treated cotton fibers herein are colored by the disperse dye. The interior of the fibers remains un-dyed and un-colored since the disperse dyes used herein do not penetrate beyond the copolymer-treated fiber surface.
Typically, even with cotton fibers, the dispersed dyed textile fibers produced by the present process exhibit at least one and typically all of the following properties:
Post-Dyeing Operations
The dyed fibrous materials produced by the dyeing method herein can be subjected to any conventional post-dyeing treatment. One such typical post-dyeing operation comprises a further wash down step which serves to remove a portion of dye from all or portions of the dyed fabric. Such a wash down operation gives even new fabrics or garments a fashionable worn or used appearance as, for example, with stone-washed denim blue jeans. Typical wash down techniques involve washing the dyed fabrics with an abrasive material such as stones, perlite, pumice, sand and/or diatomaceous earth.
The invention will now be more particularly described with reference to the following non-limiting Examples.
Acrylic Emulsion Padding Pretreatment with Exhaust Disperse Dyeing
A pad bath of 50% solid acrylic aqueous emulsion (consisting of 89 wt % Ethyl acrylate, 8 wt % Acrylonitrile and 3 wt % N-methylolacrylamide (NMA)) is made into a 10% solids pad bath by diluting 200 grams of the acrylic emulsion in 800 grams of water. The two are then mixed. A woven cotton fabric is placed in the pad bath to saturate the fabric before padding.
The fabric is then removed from the pad bath and the remaining pad bath is placed in the pad liquor trough of a Mathis Padder device. The fabric is run through the Mathis Padder under conditions of 1 bar pressure and a speed of 1 m/min. The fabric is then squeezed between the padder rollers under these conditions. The fabric is then dried in an oven at 150° C.
A disperse dye formulation consisting of 1.60% on weight of goods (owg) of Terasil Yellow BRLF (blended chemistry dye), 0.59% owg of Terasil Rubine 2GFL (monoazo dye), and 2.38% owg of Terasil Blue RBS (monoazo dye) is mixed together. These Terasil dyes are all commercially available from Huntsman Corporation.
The disperse dye formulation is then used to treat the dried cotton fabric in an exhaust dyeing operation carried out in a garment washer. The fabric is placed in the garment washer which is then filled with 9 liters of water at a temperature of 27° C. The disperse dye formulation is then added to the fabric and water mixture. A Liquor Ratio of 20 parts bath to 1 part fabric is used and the temperature of the dyeing bath is increased at a ramp rate of 3° C./ minute. The temperature is held for 60 minutes once 95° C. was reached. The fabric is then cooled after the dye cycle to 82° C., and the bath is then drained.
Three rinse cycles are then performed: The garment washer is filled with hot (60° C.) water at 20:1 liquor ratio, run for 3 minutes, and the bath is drained. An additional two rinse cycles of warm (49° C.) water are then performed as follows: The garment washer is filled with warm water at 20:1 liquor ratio, run for 3 minutes, and the bath is drained. The fabric is then removed from the garment washer and dried at 105° C.
Testing of the colorfastness of the dyed fabric to wet and dry crocking according to AATCC Test Method 8 gave the following values: wet=3-4 and dry=4, while testing of the colorfastness of the dyed fabric to light according to AATCC Test Method 16 Option 3 (using a xenon light source) gave a value of 4 after 20 hours and 3-4 after 40 hours. Testing of the colorfastness of the dyed fabric to accelerated laundering according to AATCC Test Method 61 (IIA) gave a value of 3 after 5 accelerated wash cycles.
Emulsion Copolymer Extraction/Exhaust with Exhaust Disperse Dyeing
A bath of 50% solid acrylic emulsion (consisting of 58 wt % Ethyl acrylate, 39 wt % Butyl acrylate and 3 wt % N-methylolacrylamide (NMA)) is made to a 10% solids bath by diluting 1 liter of acrylic emulsion in 4 liters of water. A woven cotton fabric is placed in the bath to saturate the fabric before extraction. The saturated fabric is then placed in a garment washer and extracted for 1 minute at a speed of 400 rpm. The fabric is removed from the garment washer and dried at in an oven at 150° C.
A disperse dye formulation consisting of 2.3% on weight of goods (owg) of Dianix Red AC-E (blended chemistry dye), and 0.69% owg of Dianix Yellow AC-E (blended chemistry dye) is mixed together. These Dianix dyes are all commercially available from DyStar L.P.
The disperse dye formulation is then used to treat the dried cotton fabric in an exhaust dyeing operation carried out in a garment washer. The fabric is placed in the garment washer which is then filled with 25 liters of water at a temperature of 27° C. The disperse dye formulation is then added to the fabric and water mixture. A Liquor Ratio of 20 parts bath to 1 part fabric is used and the temperature of the dyeing bath is increased at a ramp rate of 3° C./ minute. The temperature is held for 60 minutes once 95° C. was reached. The fabric is then cooled after the dye cycle to 82° C., and the bath is then drained.
Three rinse cycles are then performed: The garment washer is filled with hot (60° C.) water at 20:1 liquor ratio, run for 3 minutes, and the bath is drained. An additional two rinse cycles of warm (49° C.) water are then performed as follows: The garment washer is filled with warm water at 20:1 liquor ratio, run for 3 minutes, and the bath is drained. The fabric is then removed from the garment washer and dried at 105° C.
Testing of the colorfastness of the dyed fabric to wet and dry crocking according to AATCC Test Method 8, to light according to AATCC Test Method 16 Option 3 (using a xenon light source) and to accelerated laundering according to AATCC Test Method 61 (IIA) gave the same values as the dyed fabric of Example 1.
Terpolymer Emulsion Padding Pretreatment with Exhaust Disperse Dyeing
A pad bath of 50% solid vinyl aqueous emulsion (consisting of 71 wt % Vinyl acetate, 19 wt % Ethylene, 4 wt % Butyl Acrylate and 6 wt % N-methylolacrylamide (NMA)) is made into a 10% solid pad bath by diluting 200 grams of the acrylic emulsion in 800 grams of water. The two are then mixed. A woven cotton fabric is placed in the pad bath to saturate the fabric before padding.
The fabric is then removed from the pad bath and the remaining pad bath is placed in the pad liquor trough of a Mathis Padder device. The fabric is run through the Mathis Padder under conditions of 1 bar pressure and a speed of 1 m/min. The fabric is then squeezed between the padder rollers under these conditions. The fabric is then dried in an oven at 150° C.
A disperse dye formulation consisting of 1.60% on weight of goods (owg) of Terasil Yellow BRLF (blended chemistry dye), 0.59% owg of Terasil Rubine 2GFL (monoazo dye), and 2.38% owg of Terasil Blue RBS (monoazo dye) is mixed together. These Terasil dyes are all commercially available from Huntsman Corporation.
The disperse dye formulation is then used to treat the dried cotton fabric in an exhaust dyeing operation carried out in a garment washer. The fabric is placed in the garment washer which is then filled with 9 liters of water at a temperature of 27° C. The disperse dye formulation is then added to the fabric and water mixture. A Liquor Ratio of 20 parts bath to 1 part fabric is used and the temperature of the dyeing bath is increased at a ramp rate of 3° C./ minute. The temperature is held for 60 minutes once 95° C. was reached. The fabric is then cooled after the dye cycle to 82° C., and the bath is then drained.
Three rinse cycles are then performed: The garment washer is filled with hot (60° C.) water at 20:1 liquor ratio, run for 3 minutes, and the bath is drained. An additional two rinse cycles of warm (49° C.) water are then performed as follows: The garment washer is filled with warm water at 20:1 liquor ratio, run for 3 minutes, and the bath is drained. The fabric is then removed from the garment washer and dried at 105° C.
This application claims the benefit of the filing dates of U.S. Provisional Application No. 61/470,112 filed Mar. 31, 2011 and U.S. Provisional Application No. 61/605336 filed Mar. 1, 2012, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61470112 | Mar 2011 | US | |
| 61605336 | Mar 2012 | US |
