IL26167A - Furfural as a dyeing assistant - Google Patents

Description

923 34? Patents Form No. 3 PATENTS AND DESIGNS ORDINANCE.

SPECIFICATION.

"FURFURAL AS A DYEING ASSISMT" do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following s tatement : - This invention relates to a novel method for dyeing synthetic fibers, natural fibers, and combinations of synthetic and natural fibers. More specifically, the invention relates to a novel method wherein a dyeing assistant is used to fix the dyestuff in the fibers.

Dyeing, in the generic sense, consist essentially of placing a fiber into a dyestuff (usually an aqueous solution) and holding the fiber and the dyestuff in contact with each other for a sufficient time at a sufficient temperature. Agents such as electrolytes, acids, carriers, etc. may be present within the dyestuff solution to promote dyeing.

Take-up of the dye in the fiber is at a measureable rate until equilibrium is finally established with most of the dye absorbed on the fiber and a small part remaining in the dyestuff solution. The take-up rate of the dye in the fiber depends on each particular fiber and on the particular dyestuff; it is measured in percent take-up, e.g., a 100% take up means that a 1 gram sample of fiber has absorbed 1 gram of dyestuff.. In the early stages of dyeing a cross-section of the fiber shows ring dyeing and in the latter stages of dyeing, that is when equilibrium is almost obtained, a cross- section of the fiber shows that the dye has progressed from the ring or outer perimeter of the fiber to the core. The gaging of the dyeing through the cross-section of the fiber is measured in terms of penetration from 1 to , <=>»g»» a penetration of 1 indicated the fiber is dyed only on the surface or outer perimeter of the fiber whereas a penetration of 5 indicated the fiber is dyed all the way through the cross- section of the fiber. necessary to carry out the dyeing at high temperatures and/or at high pressures for a sufficient period of time. High- temperature dyeing has some advantages in that shorter dyeing times are realized, a full range of colors are possible on generally hydrophobic synthetic fibers without the use of costly carriers, and better levelling properties are obtained. However, disadvantages are associated with the high-temperature dyeing in that higher costs are usually experienced in such an installation, greater care is needed in the preparation of such a procedure, and certain dyestuffs and fibers are not stable at these high temperatures. The high temperature and high pressure dyeing systems generally have the same advantages and disadvantages but due to the high pressure of the system the cost of installation is usually compounded.

Pressure-dyeing methods are applicable with porous fabrics, loosely constructed fabrics. In this method pressure is used as a mover to push the dyestuff through the fabric. Tightly woven fabrics, e.g. nylon fabrics weighing 6 oz. per sq. yd., due to their close porosity can not be effectively dyed by this method. To overcome this disadvantage, high temperatures have been incorporated into the pressure-dying method; however, such a system still experiences difficulty with fabrics that do not have a fairly open structure. Due to the high pressure required for these systems, installation and equipment costs are very high.

A number of methods have been proposed in the past for dyeing fibers, including synthetic fibers such as many of these methods have turned out to be disadvantageous for a number of reasons. In many cases, the synthetic fibers dyed by these methods have proved to have poor light fastness and/or poor wash fastness. Other methods have resulted in altering the chemical characteristics of the fibers and thus have proved inaffective in dyeing fibers with desirable characteristics .

It is therefore an object of this invention to provide a novel method for dyeing synthetic fibers, natural fibers, and combinations of synthetic and natural fibers.

It is also an object of this invention to provide a novel, economical method for dyeing synthetic fibers, natural fibers, and combinations of synthetic and natural fibers.

It is an object of this invention to provide a method for dyeing synthetic fibers which results in full penetration of the dyestuff in the fiber.

It is an object of this invention to provide a method for dyeing synthetic fibers with broad classes of dyestuff.

Another object of this invention is to provide a method for dyeing acrylic, polyamides, and polyester fibers with broad classes of dyestuff .

Still further, it is an object of this invention to provide a method for dyeing fibers of acrylic, polyamide, polyester, or blends of each with natural fibers in which the dyestuff fully penetrates the fibers resulting in good light fastness and wash fastness. are accomplished by providing a method of dyeing a fiber comprising contacting the fiber with a dyestuff then treating the fiber with vapors of water and furfural.

Fibers useful within this invention include synthetic fibers, natural fibers, and combinations of the two. For purposes of this invention, it is intended that-synthetic fibers be defined as fibers made from natural polymers and fibers made from synthetic polymers.

Fibers made from natural polymers include rayon fibers, i.e., fibers composed of regenerated cellulose , and regenerated cellulose in which substituents have been added to replace not more than 1 % of the hydrogens of the hydroxyl groups, and acetate fibers (fibers wherein the fiber-forming substance is cellulose acetate and not less than 92 of the hydroxyl groups are acetylated).

Examples of rayon fabrics include viscose, cuprammonium, and rayon fabrics having trade names such as Avril, Zantrel, Corval, and Fortisan. Examples of acetate fibers include acetate, and acetate fibers having trade names such as Arnel, and Arnel 60.

Fibers made from synthetic polymers include spandex (a fiber in which the fiber-forming substance in any long-chain synthetic polymer composed of at least 85$ by weight of a segmented polyurethane ) , polyester (a fiber in which the fiber-forming substance is any long-chain synthetic polymer composed of at least 85$ by weight of an ester of a dihydric alcohol and terephthalic acid), nylon [a fiber in which the fiber-forming substance is any long-chain synthetic polyamide having recurring amide groups [a fiber in which the fiber-forming substance is any long-chain synthetic polymer composed of at least QS° by weight of acrylonitrile units (-CHP- -)], and modacrylic [a fiber in which the fiber-forming substances is any long-chain synthetic polymer composed of less, than 85$ but at least 3 $ by weight of acrylonitrile units (-CH2-CH-)]. Examples of spandex CN includes fibers having trade names such as Lycra, Vyrene, and Blue "C" Spandex. Trade names of polyester fiber include names such as Dacron, Kodel, Portrel, Vycron, Terylene, and Blue "C" Polyester. Examples of trade names of acrylic fibers include Orion, Acrilan, Zefran, Courtelle, and Creslan. Nylon fabric examples include nylon 6 and nylon 6,6. Examples of modacrylic fibers include trade names such as Dynel, Verel, anekalon and Teklan.

Natural fibers useful with this invention include cotton, wool, and silk. Blends of natural fibers and synthetic fibers are also useful in this invention. Examples of such blends include acrylic and cotton, acrylic and wool, nylon and cotton, polyester and silk, polyester and wool, polyester and cotton, e.g. 65$ polyester and 35$ cotton.

Vicara a fiber made from maize protein, is also useful with the invention.

This invention is particular applicable to fibers made from polyacrylonitrile and also to copolymers, interpolymers , and blends thereof, particularly blends containing at least 80$ by weight of polymerized or co-polymerized acrylonitrile. Such polymeric materials include basic copolymers and to blends containing an overall polymerized acrylonitrile content of at least about Q0% by weight. For example, the polymer may be a copolymer of from about 80 to about 96% of acrylonitrile and from about 2% to about 20% of another copolymerizable mono-olefinic monomer such as acrylic, alphachloro-acrylic and methacrylic acids, the acrylates, (e.g. methylmethacrylate, buthylmeth-acrylate, methoxymethylmethacrylate, beta-chloroethylmeth-acrylate, and the corresponding esters of acrylic and alpha-chloroacrylic acids) vinyl chloride, vinyl fluoride, vinyl Bromide, vinylidene chloride, l-chloro-l-bromoethylene; methacrylonitrile; acrylamide and methacrylamide; alpha-chloroacrylamide, or monoalkyl i substitution products thereof; methyl vinyl keton'; vinyl carboxylates , such as vinyl acetate, vinyl chloroacetate, vinyl propionate, and vinyl stearate; N-vinyl-imides, such as N-vinylphthalimide and N-vinyl-succinimide; methylene malonic ester; itaconic acid and itaconic ester; N-vinyl carbazole-; vinyl furan; alkyl vinyl esters; vinyl sulfonic acid; ethylene alpha, beta-dicarboxylic acids or their anhydrides or derivatives thereof, such as diethylcitraconate, diethylmesaconate; styrene; vinyl naphalene; vinyl-subs ituted tertiary heterocyclic amines such as the vinylpyridines and alkyl-substituted vinylpyridines, e.g., 2-vinylpyridine , !+-vinylpyridine, 2-methyl-5-vinylpyridine, and the like; l-vinylimidazole and alkyl-substituted l-vinylimidazoles , such as 2-, Ij.-, or 5-methyl-1-vinylimidazole , vinylpyrrolidone , vinylpiperidone, and other mono-olefinic copolymerizable monomeric materials. interpolymer, e.g., products obtained by the interpoly-merization of acrylonitrile and two or more of any of the above enumerated monomers, other than acrylonitrile. More specifically, and preferably, the ternary polymers can obtain from about 80 to about 98 percent of acrylonitrile, from about 1 to about 10 percent of a vinylpyridine or 1-vinylimidazole, and from about 1 to about 18 percent of another copolymerizable mono-olefinic substance, such as methacrylonitrile, vinyl acetate, methylmethacrylate, vinyl chloride, vinylidene chloride, and the like.

The acrylic polymer can also be a blend of polyacrylonitrile or ;of a copolymer of from about 80 to about 99 percent acrylonitrile and from about 1 to about 20 percent of at least one other mono-olefinic copolymerizable monomeric substance with from about 2 to about £0 percent of the weight of the blend of a copolymer of from about 30 to about 90 percent of a vinyl substituted tertiary heterocyclic amine and from about 10 to about 70 percent of at least one other mono-olefinic copolymerizable monomer. When the polymeric material comprises a blend of from about 80 to about 99 percent of a copolymer of about 80 to about 98 percent acrylonitrile and from about 2 to about 20 percent of another mono-olefinic monomer, e.g., vinyl acetate, with from about 1 to about 20 percent of a copolymer of from about 30 to about 90 percent of a vinyl-substituted tertiary heterocyclic amine, such as vinyl pyridine, l-vinylimiazole, or a vinyl lactam, and from about 10 to about 70 percent of acrylonitrile to give a dyeable blend having an overall vinyl-substituted tertiary heterocyclic amine content of blend.

Polyamide fibers are also particularly applicable to this invention. These fibers are defined as linear polyamides formed by condensation of a diamine with a dibasic acid, by self-condensation of an amino acid or by a combination of both types. Polyamide fibers can also be defined as polymers having recurring units of (-N-C-) wherein R is hydrogen or a monovalent hydrocarbon radical and the average number of carbon atoms separating the amide groups is at least two. Specific examples of polyamide fibers include those obtained from polymers of tetra-methylenediamine with sebacic acid, hexamethylenediamine with adipic acid, hexamethylene diamine with suberic acid, and hexamethylenediamine with sebacic acid. Also contemplated are polyamide f bers obtained from polymerization of two or more different diamines with a dicarboxylic acid or two or more different dicarboxylic acids with a diamine or two or more different dicarboxylic acids with two or more different diamines. Thus polyamide as used in this invention is defined to encompass the above.

Polyester fibers are also particularly applicable in this invention as are blends of polyesters and natural fibers, e.g. polyester and cotton, polyester and silk, and polyester and wool. Polyester fibers are defined as having a long-chain synthetic polymer composed of at least 85$ by weight of an ester of a dihydric alcohol and tereph-thatic acid, e.g., terephthatic acid with ethylene glycol, dimethyl ester of terephthatic acid with ethylene glycol. specifically applicable to this invention.

The dyestuffs useful in this invention include all types of dyestuffs, e.g., acid dyestuffs, basic dye- stuffs, direct dyestuffs, disperse dyestuffs, premetallized dyestuffs, etc. Particular fibers have an affinity to particular dyestuffs, it is therefore preferred that acid dyestuffs be used with acrylic, and polyamidej basic dyestuffs be used with acrylic, and silk; direct dyestuffs be used with cotton, polyamide, and silk; disperse dye-stuffs be used with acetate, acrylic, polyester, and polyamide; and premetallized dyestuffs be used with acrylic, and polyamide. A list of useful dyestuffs can be found in Technical Manual of the American Association of Textile Chemists and Colorists, Volume XXXVIII, 1962.

Application of the dyestuff on the fiber can be accomplished by many methods, e.g., by immersing the fiber in an aqueous solution of the dyestuff, by spraying the dyestuff on the fiber, by kiss rolling the dyestuff on the fiber, by padding the dyestuff on the fiber, etc. The dyestuff can be in an aqueous solution containing additives knowftto those people in the art, e.g., levelling agents such as cationic compounds, acids (formic acid, acetic acid, etc.), slightly alkaline salts (soda ash, sodium acetate, tetra-sodium pyrophosphate, etc.), additives to adjust the viscosity and prevent migration of the dyestuff (a purified natural gum ether, sodium alginate, etc.) various surfactants, retarding agents, etc. It is understood as common knowledge within the art that certain additives are desired for certain dyestuffs . it is treated with vapors of water and furfural. This treatment fixes the dyestuff in the fiber and results in a dyed fiber having good wash fastness and color fastness.

Before the fiber containing dyestuff is treated with the vapors of water and furfural, it is preferred that the fiber be heated to and maintained during the treatment at a temperature of from about 150°F. to about 300°P. (175°P. to about 2^0° being the preferred range) or that the fiber be dried, preferably at a temperature within the range of from about 212°P. to about 300°P. If the fiber is not dried or if it is maintained at a temperature below about 150°P., there is a possibility that furfural might form a resin "cap" on the fiber and prevent the dye from penetrating in to the fiber.

The vapors of water and furfural should be within the range of from about 210°P. to about 250°F. At these temperatures, the concentration of furfural in water vapors should be within the range of from about 1 to about SS by weight of furfural. Lower concentrations of furfural can be used, however, at lox^er concentrations full penetration of the dyestuff in the fiber may not be as effectively obtained. Also, if higher concentrations of furfural are used, e.g. about 75$» there is a probability that some of the dyestuff on the fiber will be dissolved in the furfural. The concentration of furfural in the water vapors can be below the saturation point of the vapors, can be saturated in the water vapors; or it can be above the saturation point of the vapors (entrained in the water vapors). For example, a saturated solution of furfural in water at 50°P. 1 and at the boil (208.8°P. and 760 mm.) a composition of 29.6$ furfural by weight in the water vapors, and a saturated solution at 208.2°F. and 760 mm. has water vapors containing 35$ furfural by weight. At higher temperatures, for example at 2l5°P. the water vapors can contain about fo furfural by weight. For purposes of this invention, it is preferred that the water vapors be saturated with furfural; however, entrained furfural in the water vapors and within the above concentrations are also preferred.

The treatment of the dyestuff contacted fiber with vapors of water and furfural should be for a sufficient period of time and at a sufficient temperature, i.e., from about 1 to about 10 minutes and at a temperature of from about 210°P. to about 27f?°F. , the preferred range being from about 20j?°F. to about 2i|50F. If the temperature of the vapors is at about 2\ $ °¥ . the period of time can be shorter, for example about 3 minutes; if the temperature of the vapors is at about 212°F. the period of time can be longer, about 7 minutes. A prolonged period of time at higher temperatures, i.e. in excess of 30 minutes at 250°P. will have a detrimental effect on the fiber.

There are many methods to generate the vapors of water and furfural, e.g., by maintaining a water and furfural mixture at its boiling point, introducing vaporized water (steam at different pressures) into the bottom of a body of furfural, etc. The methods can be adapted to a continuous dyeing system.

The following examples are presented to specifically illustrate the invention. These examples are presented to give a working knowledge of the same. It is to be understood also that the iraention is not to be limited by the dyes disclosed, but any dye or combination of dyes which are useful on the synthetic fibers and the natural fibers may be used according to the invention with vapors of water and furfural. Examples I, IV, V, VI, and VII illustrate the effectiveness of furfural and water vapors over water vapors exempt of furfural. All percents are by weight unless otherwise illustrated.

EXAMPLE I Swatches of polyester fiber and polyamide fiber were immersed for 0.5 seconds at room temperature with a dyestuff containing 20 grams per liter of Resolin Blue PBL paste (C.I. Disperse Blue 71), 160 grams per liter of sodium alginate solution {≥% chemical), and 820 grams of water, and then padded at l+O psi. Half of the swatches were treated for 5 minutes with vapors emitted from a solution maintained at 212 °P. and containing 200 cc of furfural in 2,000 cc of water. The other half of the swatches were treated for £ minutes with 212°P. vapors emitted from water. Both halfs were washed afterwards for 10 minutes at 160°P. in an aqueous solution containing 2 grams per liter of a non-ionic detergent (Igepal CO-710). The samples treated with 212°P. water vapors showed heavy bleeding; however, the samples treated with vapors of water and furfural showed no bleeding and exhibited a shade of blue twice the depth as the one treated with 212°P. water vapors.

. EXAMPLE II of 76.5$ of a copolymer being 93 acrylonitrile and 7% vinyl acetate, 10.1$ of a copolymer being ½0% acrylonitrile and 50% methylvinyl pyridine and 13$ of polyvinylchloride were sprayed with an aqueous dyestuff containiing 1 gram per liter of Anthraquinone Blue SWT (C.I. Acid Blue 25 ) , enough formic acid to adjust the pH to 2. 0, and enough of a 20% solution of purified natural gum ether to adjust the viscosity to 175 c.p. The swatch was treated for 5 minutes with vapors emitted from a boiling aqueous solution containing 9% furfural. The swatch showed a heavy shade of blue and, upon examining the fiber, a cross-section penetration of k-5> EXAMPLE III A swatch of acrylic carpet sample described in Example II was sprayed with an aqueous dyestuff containing Ο.25 gram per liter of Calcozine Arcylic Red 3G (C.I. Basic Red 30 ) , 0.25 gram per liter of Genacryl Blue 3G (C.I. Basic Yellow 28 ) , enough soda ash to adjust the pH to 9.5 and enough of a 20% solution of a purified natural gum ether to adjust the viscosity to 175 c.p. After treating the swatch for 5 minutes with vapors emitted from a boiling aqueous solution containing 9% furfural, it was observed that the sample had a heavy shade of color. Further examination of the fiber showed a cross-section penetration of I4.-5.

EXAMPLE IV A sample of cotton was padded with an aqueous dyestuff solution containing 10 grams per liter of Pontamine Fast Yellow RL (C.I. Direct Yellow 0 ) and 160 grams per treated for 5 minutes with atmospheric steam and the other half was treated for 5 minutes with atmospheric steam saturated with furfural. The sample treated with steam saturated with furfural showed l|.0$ heavier shading than the sample treated with steam exempt of furfural.

EXAMPLE V The procedure of Example IV was repeated except the aqueous dyestuff solution containing 10 grams per liter of Diphenyl Past Light Red 6 BP (C.I. Direct Red ) in place of Pontamine Past Yellow RL. The sample treated with atmospheric steam saturated with furfural showed a shade 100$ heavier in color than the sample treated with steam exempt of furfural.

EXAMPLE VI The procedure of Example IV was repeated except 10 grams per liter of Chlorantine Past Blue 7G-LL (C.I. Direct Blue 76) was used in place of Pontamine Past Yellow RL. The sample treated with atmospheric steam saturated with furfural showed a shade l\.0% heavier in color than the sample treated with steam exempt of furfural.

EXAMPLE VII Two fiber samples each composed of 76.5$ of a copolymer being 93$ acrylonitrile and 7$ vinyl acetate, .5$ of a copolymer being 0$ acrylonitrile and 0$ methyvinyl pyridine, and 13$ of polyvinylchloride, and sprayed with a dyestuff containing 1 gram per liter of Anthraquinone Blue SWF (C.I. Acid Blue 25) enough formic acid to adjust the pH to 2, and enough of a 20$ solution of purified natural gum ether to adjust the viscosity to 171 treated for 5 minutes with atmospheric steam; the other sample was treated for 5 minutes with vapors emitted from boiling aqueous solution of 9% furfural. The fiber sample treated with atmospheric steam showed a penetration of 1 whereas the sample treated with the vapors of the boiling aqueous solution of 9% furfural showed a penetration of I . to and had a shade $0% heavier in color than the sample treated with atmospheric steam.

EXAMPLE VIII A fiber sample composed of 93$ acrylonitrile and 7 vinyl acetate was padded at lij.0°F. with an aqueous dyestuff containing 10 grams per liter of Seyron Orange L (C.I. Basic Orange 21).), 1 gram per liter of a purified natural gum ether (Polygum 260) and 0,5 gram per liter of a modified polyglycol ether (Tanapon X-70). The sample was heated at 2l.0°F. for 5 minutes and was then treated for one minute with 212°P, steam saturated with furfural.

Thereafter, the sample was rinsed cold, scoured for 10 minute at the boil in an aqueous solution containing one gram per liter of a modified polyglycol ether (Tanapon X-70) and one gram per liter of tetrasodium pyrophosphate, and then dried. The fiber sample showed a deep shade of orange fast to washing and to crocking.

EXAMPLE IX A fiber sample composed of 93% arcylonitrile and 7 vinyl acetate was padded at lI|.0oP. with an aqueous dyestuff containing 10 grams per liter of Basacryl Blue GL (C.I. Basic Blue j¾), 1 gram per liter of a purified natural gum ether (Polygum 260), and 0.5 gram per liter of a dried at 2ί0°Ρ. and treated for one minute with atmospheric steam saturated with furfural. Thereafter, the sample was rinsed cold, scoured 10 minutes at the boil in an aqueous solution containing one gram per liter of a modified polyglycol ether (Tanapon X-70) and one gram per liter of tetrasodium pyrophosphate, and then dried. A deep shade of blue fast to washing and to crocking was observed on the sample .

EXAMPLE X A fiber sample composed of 93$ acrylonitrile and 7$ vinyl acetate was padded at li).0oF. with an aqueous dyestuff containing 10 grams per liter of Maxilon Red BL (C.I. Basic Red 22), 1 gram per liter of a purified natural gum ether (Polygum 260), and 0.5 gram per liter of a modified polyglycol ether (Tanapon X-70). The sample was dried at 2ij.0°F. and thontreated for 1 minute with atmospher steam saturated with furfural. Thereafter, the sample was rinsed cold, scoured for 10 minutes at the boil in an aqueous solution containing a modified polygylcol ether (Tanapon X-70) and one gram per liter of tetrasodium pyrophosphate, and then dried. The sample showed a deep shade of red fast to washing and crocking.

EXAMPLE XI A fiber sample composed of 65$ of a polyester obtained from the polymerization of tetrephthatic acid and ethylene glycol and y~>% of cotton was padded at 120°P. with an aqueous dyestuff containing 16 grams per liter of Latyl Blue LS 0 Paste (C.I. Disperse Blue 62), 1 gram per liter of sodium alginate and 0. gram per liter of a sodium dried at 2l|.0oF., treated for one minute with atmospheric steam saturated with furfural, then scoured for 10 minutes at the boil in an aqueous solution containing one gram per liter of a non-ionic detergent and one gram per liter of tetrasodium pyrophosphate. After drying, the polyester fibers showed a medium shade of blue fast to washing and to crocking.

EXAMPLE XII The procedure of Example XI was repeated except the fiber sample was treated for five minutes with 212°P., steam saturated with furfural, The sample was observed to have a heavier shade of blue than Example XI fast to washing and to crocking.

EXAMPLE XIII A multi-fiber strip containing fiber samples of acrylic, polyamide, silk, vicara, and wool was padded at 120°P. with an aqueous dyestuff containing 5 grams per liter of Irgalan Yellow GL (C.I. Acid Yellow 111+ ), a pre-metalized dyestuff. The strip was dried by maintaining it at 210°P. for $ minutes. It was then treated for minutes with vapors from a boiling aqueous solution containing 100 cc. per liter of furfural. Thereafter the strip was rinsed and scoured for 5 minutes at the boil in an aqueous solution containing 1 gram per liter of tetrasodium pyrophosphate and 1 gram per liter of a non-ionic detergent. After the strip was rinsed and dried each of the fiber samples showed a good shade of yellow.

EXAMPLE XIV A multi-fiber strip containing fiber samples with an aqueous dyestuff containing 5 grams per liter of Brilliant Alizarine Milling Blue BL (C.I. Acid Blue 80), an acid dyestuff. The strip was dried at 210°P. and was then treated for 5 minutes with vapors from a boiling solution containing 100 cc per liter of furfural in water. Thereafter, the strip was rinsed and scoured for 5 minutes at the boil in an aqueous solution containing 1 gram per liter of tetrasodium pyrophosphate and 1 gram per liter of a non-ionic detergent. After rinsing and drying all the fiber samples showed a deep shade of blue.

EXAMPLE XV A multi-fiber strip containing fiber samples of acrylic, silk, and vicara was padded at 120°P. with an aqueous dyestuff containing 5 grams per liter of Sevron Red GL (C.I. Basic Red 18), a basic dyestuff. The strip was dried at 210°F. and was then treated for 5 minutes with vapors emitted from an aqueous boiling solution containing 100 cc per liter of furfural. The strip was rinsed and scoured for minutes at the boil with an aqueous solution containing 1 gram per liter of tetrasodium pyrophosphate and 1 gram per liter of a non-ionic detergent. After rinsing and drying the strip, all the fiber samples showed a deep shade of red.

EXAMPLE XVI A multi-fiber strip containing fiber samples of acrylic, cotton, polyamide, silk, and vicara was padded at 120°P. with an aqueous dyestuff containing grams per liter of Direct Past Yellow BWP (C.I. Direct Yellow 28), a direct dyestuff. After the strip was dried at 210°P., solution containing 100 cc per liter of furfural in water. Thereafter the strip was rinsed and scoured for $ minutes at the boil in an aqueous solution containing 1 gram per liter of tetrasodium pyrophosphate and 1 gram per liter of a non-ionic detergent. After the strip was rinsed and dried all the fiber samples showed a deep shade of yellow.

EXAMPLE XVII A multi-fiber strip containing fiber samples of acetate, acrylic, polyester, and polyamide was padded at 120°P. with an aqueous dyestuff containing grams per liter of Latyl Cerise B (C.I. Disperse Red 59), a disperse dye-stuff. The strip was dried by maintaining it at 210°P. for 5 minutes with vapors emitted from an aqueous boiling solution containing 100 cc per liter of furfural. Thereafter the strip was rinsed and scoured for minutes at the boil in an aqueous solution containing 1 gram per liter of a non-ionic detergent. After the strip was rinsed and dried, all the fiber samples showed a deep shade of red.

Claims (3)

1. HAVING NOW particularly aeecri ed and ascertained th© nature ^ of our said invention and in what manner the same is to be performed, we declare that what we claim is t 1 . A method of dyeing a fiber characterized by contacting the fiber which a dyestuff then treating the fiber with vapors of water and furfural.

2. The method of Claim 1 , characterized in that the fiber is a synthetic fiber.

3. The method of Claim 1 , characterized in that the fiber is a natural fiber. ij.. The method of Claim 1 , characterized in that the fiber is a blend of a synthetic fiber and a natural fiber. 5. The method of Claim 1 , characterized in that the dyestuff is selected from the group consisting of acid dyestuffs, basic dyestuffs, dispersed dyestuffs, direct dyestuf s, and premetalized dyestuffs. 6. The method of Claim 1 , characterized in that the vapors of water and furfural are at a temperature within the range of from about 205°P. to about 212°P. 7. The method of Claim 1, characterized in that the vapors of water and furfural have a concentration of from about 7.5$ to about by weight of furfural. 8. The method of any of Claims 1-7, characterized by heating to and maintaining the fiber at a temperature of from about 175°P. to about 300°P. prior to treating the fiber with vapors from a boiling aqueous mixture of furfural and water, the concentration of furfural being at about 7.5% to about $fo by weight. 9. The method of Claim 8, characterized in that the fiber is an acrylic fiber. 2616†/2 In that the fiber is a polyamide fiber, 11· The method of claim 8, characterized in that the fiber is a polyester fiber. 12. The method of claim 6» characterized in that the fiber is a blend of polyester fiber and cotton fibe . 13· The method of any of claims 8-12, characterized in that the vapors of water and furfural are at a temperature of from about 205PF. to about 212°F. Ak» A method of dyeing a fiber substantially as described in the herein Examples. 15· Dyed ibers whenever produced by the method claimed in any one of the preceding claims.