Cross-Reference to Related Applications

[0001] This application is an International Application which claims priority to Provisional Patent Application No. 63/111,817, filed on November 10, 2020, the entire contents of which is incorporated by reference in its entirety.

Field of the Invention

[0002] The field of the invention is improved processes and methods for dyeing textiles, especially as it relates to cold pad batch dyeing using reactive dyes.

Background of the Invention

[0003] The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[0004] All publications and patent applications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0005] Textile dyeing is the process of applying pigments or dyes on textile materials such as fabrics, yams, and fibers. Desirably, the dyeing process is efficient and rapid, and provides the dyed textile with a desired degree of coloring, and resistance to fading and running of the dye (color fastness). Further, the dyeing process and the materials used therein preferably do not adversely affect the aspects of the textile, such as its flexibility, durability, and tactile properties like softness, smoothness, stiffness. Depending on the material of the textile (e.g., natural, synthetic, or mixtures thereof) and desired coloring, various dye types are used.

[0006] Common dyes for cotton have a negative charge. However, in an aqueous solution the surface of the cotton fiber has a neutral or mildly negative charge due to the presence of hydroxyl groups of the cellulosic material that constitute the cotton. Negatively charged dyes get repelled by negatively charged cellulosic material resulting in less dye uptake by the cotton. In order for the textile to be dyed, the surface properties of the cotton fiber must be altered so the dye is not repelled. Traditional dyeing of cotton-based textiles has involved use of a mixture of salts, alkali, and dyes to associate the dye with the material of the cotton fiber. Salt is commonly used in a dyebath to reverse the charge on the cotton fiber, and alkali is used to allow the dyes to react with and associate with the induced positively charged surface of the cotton fiber. However, these traditional processes can consume significant amounts of water, energy, and chemicals, which is undesirable.

[0007] Cold pad batch dyeing (CPBD) is a well-known process for dyeing cotton knit and woven fabrics with a variety of fiber reactive dyes. In most typical processes, the prepared cotton fabric is padded with a solution of a reactive dye and alkali. The padded fabric is then wound on a beam and held for a period of time to allow the dye to react with the fabric. After the reaction is completed, the fabric is rinsed to remove any unfixed dye. Unfortunately, while conceptually simple, dyeing efficiency is often less than desirable resulting in shade variation from selvage to selvage, in the running length of the fabric, variation from lot to lot, and a high demand on dye and large quantities of unreacted/hydrolyzed dye that must be properly disposed of or that otherwise is a substantial pollutant.

[0008] In an effort to increase dyeing efficiency, cotton fabric can be pre-treated prior to dyeing with a reagent that attaches a cationic group to the cotton that then in turn can react with the dye for improved dyeing efficiency. 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC) is a well-known cationizing agent for cationizing cotton that has helped reduce pollution, energy and water usage, and led to shorter dye cycles (see U.S. Pat. App. Pub. No. 2018/0038047 Al; Chinese Pat. App. Pub. No. 113372562 A; U.S. Pat. No. 7,201,778 B2). CHPTAC can be reacted with the hydroxyl groups of cellulose in the presence of alkali. In first step, the CHTAC is dechlorinated to form the reactive intermediate epoxypropyl trimethyl ammonium chloride (EPTAC), and the epoxide group of this compound can react with a deprotonated hydroxyl group of cellulose, thereby covalently linking the cationic ammonium chloride group to the cellulose backbone through an ether linkage. Typically, the cationization process is carried out by padding the cotton fabric with a solution of CHPTAC and alkali with expensive precise pretreatment machinery, winding the padded fabric on a beam, letting the fabric and cationization chemistry cure for 12 hours and rinsing the fabric after the reaction is completed in an exhaust dye jet or a continuous wash range. The cationized fabric is then dyed in a continuous open width dyeing range (stentor) afterwards.

[0009] Recently, efforts have been made to further reduce the dye cycles by combining the cationizing agent (e.g, CHPTAC), the reactive dye, and the alkali to form a solution and then pad dyeing cellulosic fiber with the solution to dye the fabric (see International Pub. No. WO 2021/158538 Al). However, due to the competing reactions between the cationizing agent and the cellulosic fiber, and between the cationizing agent and the reactive dye, a significant portion of the cationizing agent and the reactive dye precipitate out of solution thereby decreasing efficiency of the dyeing process. This precipitation also leads to significant lot-to-lot variability due to incomplete exhaustion of the dye in the process.

[0010] Furthermore, the strong ionic attraction between the so prepared cationic fiber and anionic dye also leads to high levels of dye exhaustion, drastically reducing the amount of dye discharged. Unfortunately, when CHPTAC treated cotton is heated after dyeing, a strong unpleasant odor of trimethylamine is produced through the Hofmann Elimination/Rearrangement as shown in Scheme 1 below, discouraging the commercialization of CHPTAC treated cotton.

Scheme 1.

[0011] Several attempts have been made to reduce the disadvantages known in such processes, and one example is disclosed in WO 2019/069116. Here, the inventors modified the process to be performed in a contained system in which the fabric is pretreated and in which the dyed fabric is subjected to a boric acid wash to reduce odor emission. In another known approach as described in US10640918, the inventors used modified quaternary ammonium compounds instead of CHPTAC such as CHPDMAP to avoid odor formation. However, such known alternatives are typically more capital intensive, tend to increase process complexity, and/or limit the type of fabrics suitable for use. [0012] Thus, even though various systems and methods of fabric dyeing are known in the art, all or almost all of them suffer from several drawbacks. Therefore, there remains a need for compositions and methods for improved dyeing of various cellulosic materials and particularly cotton.

Summary of The Invention

[0013] The inventive subject matter is directed to various compositions and methods of dyeing cellulosic materials on a cold pad batch dyeing (CPBD) process that combines a cationizing agent and a reactive dye into a mixture that is then mixed with a base. Within 60 seconds after mixing with the base, the cellulosic material is contacted with the mixture.

[0014] In one aspect of the inventive subject matter, the inventors contemplate a method of dyeing a cellulosic material in a CPBD process. The method includes combining a cationizing agent and a reactive dye to form an intermediate dye mixture. The method further includes combining a base and the intermediate dye mixture to form an activated dye mixture. The method further includes contacting a cellulosic material with the activated dye mixture within a time period of 60 seconds after forming the activated dye mixture to form a dyed cellulosic material.

[0015] Most typically, the cellulosic material is cotton, the cationizing agent is CHPTAC, and/or the dye is an anionic reactive dye. It is further contemplated that the base is combined with the activated dye mixture prior seconds to the step of contacting the cellulosic material. In at least some embodiments, the step of permanent bonding/reaction is equal or less than 18 hours, and more typically equal or less than 12 hours.

[0016] Where desired, contemplated methods may also include a step of washing the dyed cellulosic material. Moreover, the step of contacting may also include a step of contacting the cellulosic material or the dyed cellulosic material with a modified guanidinium phosphate compound to reduce volatile amine formation. Most typically, contemplated methods will increase dye exhaustion, reduce lot to lot variation, tailing, and/or selvage to selvage shading.

[0017] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components. Brief Description of The Drawing

[0018] FIG.l is a photograph of an exemplary CPB bleaching range suitable for use with the inventive subject matter presented herein.

[0019] FIG.2 is a photograph of an exemplary CPB washing range suitable for use with the inventive subject matter presented herein.

[0020] FIG.3 is a photograph of an exemplary CPB dyeing machine for knits suitable for use with the inventive subject matter presented herein.

[0021] FIG.4 is a photograph of an exemplary CPB dosing pumps with heat exchanger suitable for use with the inventive subject matter presented herein.

[0022] FIG.5 is an exemplary schematic for the CPB bleaching range of FIG.1.

[0023] FIG.6 is an exemplary schematic for a CPB washing range of FIG.2.

[0024] FIG.7 is an exemplary schematic for a CPB dyeing machine for knits of FIG.3.

Detailed Description

[0025] The inventors have unexpectedly discovered that dyeing of various cellulosic fabric materials in a cold pad batch dyeing CPBD process can be substantially improved by combining a cationizing agent and a reactive dye to so form an intermediate dye mixture. The intermediate dye mixture is then combined with a base (e.g., NaOH) to form an activated dye mixture. A cellulosic material is then contacted with the activated dye mixture within 60 seconds after forming the activated dye mixture to form a dyed cellulosic material. Notably, in various embodiments, the activated dye mixture is substantially free of a precipitate that does not readily associate with the cellulosic material. In some embodiments, this precipitate results from an undesirable reaction between the cationizing agent and the reactive dye independent of the cellulosic material or hydrolysis of the cationizing agent. Without being bound by theory, the inventor contemplates that contacting the cellulosic material with the activated dye mixture within 60 seconds of forming the activated dye mixture reduces the formation of the undesirable precipitate. [0026] Typically, the cationizing agent (e.g, CHPTAC) forms an activated cationizing agent (e.g, EPTAC) having a reactive group (e.g., epoxy group) in the presence of the base (e.g., NaOH), as shown in Scheme 2 below.

Scheme 2.

CHPTAC EPTAC

The reactive group (e.g., epoxide group) can react with a deprotonated hydroxyl group of cellulose, thereby covalently linking the cationic ammonium chloride group to the cellulose backbone through an ether linkage, as shown in Scheme 3 below.

Scheme 3.

EPTAC Cattoi e Cotton

It is to be appreciated that any cationizing agent may be utilized that has or forms an activated catioinizing agent having a reactive group so long as the reactive group can react with the cellulose and the cationizing agent is compatible with the method.

[0027] To this end, the inventor has unexpectedly discovered that contacting the cellulosic material with the activated dye mixture within 60 seconds of forming the activated dye mixture leads to the activated dye mixture exhibiting a substantial improvement to dye exhaustion during formation of the dyed cellulosic material, and thus a significant improvement to lot-to- lot variability of color for the resulting dyed cellulosic material. In various embodiments, the cellulosic material is contacted with the activated dye mixture within 55, 50, 45, 40 ,35, 30, 25, 20, 15, 10, or 5 seconds of forming the activated dye mixture. Indeed, the inventor further discovered that use of the activated dye mixture in the CPBD process also requires 15-20% less reactive dye than a conventional two-step or conventional one-step CPBD process to match shades, with a 95-99% dye yield compared to 80% with CPBD alone. In addition, the reaction time was reduced to 12 hours as compared to 24 hours with a traditional CPBD process. In various embodiments, the activated dye mixture includes at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, at least 15%, at least 16%, at least 17%, at least 18%, at least 19%, at least 20%, at least 21%, at least 22%, at least 23%, at least 24%, or at least 25% less reactive dye to achieve a predetermined color intensity as compared to an activated dye that is combined with a cellulosic material beyond the time period of 60 seconds after forming the activated dye mixture.

[0028] Yet a further advantage of the activated dye mixture was that rinsing time and solution (such as water and soap) was reduced by 30% compared to the traditional CPBD process, and that lot-to-lot shade reproducibility was substantially improved versus the traditional CPBD process, which allowed for improved shade matching. Thus, it should be appreciated that the activated dye mixture greatly improved production efficiency by combining two processes into one.

[0029] Most typically, the improved CPBD process is based on combining CPBD and cationization into a single process in which CHPTAC (or other cationizing agents) and fiber reactive dyes are mixed together prior to being mixed with alkali and padded onto fabric in a CPBD process. Despite the CHPTAC and the fiber reactive dyes being of opposite electrical charges, the mixture is stable with no agglomeration or precipitation. Using such process increased dye exhaustion to 95-98%, sometimes even 100% thereby minimizing off shade lot to lot reproducibility, selvage to selvage shading, length shading (called tailing) and made color matching much more precise.

[0030] In certain embodiments, the method provides at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, at least 15%, at least 16%, at least 17%, at least 18%, at least 19%, or at least 20% increase in dye exhaustion as compared to a method utilizing an activated dye that is combined with a cellulosic material beyond the time period of 60 seconds after forming the activated dye mixture. The phrase “dye exhaustion” refers to a process by which all of the reactive material, such as a dye, is used up by reacting with a substrate, such as a cationized cellulosic material. Further, it is not necessary for the material to react for it to be exhausted so long at the material is associated with the cationized cellulosic material. Exhaustion typically involves a physical affinity of the chemical species to the substrate due to hydrogen bonds, polar interactions, ionic interactions, and van der Waals or London forces.

[0031] Referring now to the cationizing agent, the cationizing agent refers to a compound that is able to associate with the cellulosic material, such as by chemical reaction resulting in covalent bonding between the cationizing agent and the cellulosic material. The reaction imparts a positive (cationic) charge to the cellulosic material.

[0032] Cationizing agents for use in methods of the disclosure include mono- and di- quatemized nitrogen compounds. The mono- and di-quatemized nitrogen compounds can include halogenated and hydroxylated ammonium compounds. In the presence of a base (e.g., alkali metal hydroxide, such as NaOH), the compound can become dehalogenated and deprotonated to form a reactive glycidyl (epoxy) intermediate compound which in turn can react with hydroxyl groups of the cellulosic material. Amine groups of chitosan-containing materials can also be reacted with glycidyl-containing ammonium compounds to provide cationization to the material.

[0033] In some embodiments, the cationizing agent may be a mono-quatemized nitrogen compound capable of generating a single epoxide group in the presence of alkali metal hydroxide (e.g., NaOH). For example, the cationizing agent may be of formula I: wherein R ¹ is an alkylene group, such as a C1-C6 alkylene group, R ² , R ³ , and R ⁴ , are independently selected from alkyl groups, such as Cl- C6 alkyl groups, and X and X’ are independently selected from halogen atoms, such as Cl, Br, or I. In certain embodiments, R ¹ is selected from the group of methylene, ethylene, and propylene, and R ² , R ³ , and R ⁴ , are independently selected from the group of methyl, ethyl, and propyl. In some exemplary embodiments, the cationizing agent is 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC). Other suitable cationizing agents can be found in U.S. Pat. No. 5,006,125, which is incorporated herein by reference in its entirety.

[0034] In other embodiments, the cationizing agent may be a di-quatemized nitrogen compound capable of generating two epoxide groups in the presence of alkali metal hydroxide (e.g, NaOH). For example, the cationizing agent may be of formula II: wherein R ¹ and R ¹ ’ are independently selected from alkylene groups, such as a C1-C6 alkylene group, R ² , R ² ’, R ³ , and R ³ ’ are independently selected from alkyl groups, such Cl- C6 alkyl groups, R ⁴ , and R ⁴ ’ are independently selected from alkylene groups, such as C1-C6 alkylene groups, and X and X’ are independently selected from halogen atoms, such as Cl, Br, or I. In certain embodiments, R ¹ and R ¹ ’ are independently selected from the group of methylene, ethylene, and propylene, R ² , R ² ’, R ³ , and R ³ ’, are independently selected from the group of methyl, ethyl, and propyl, and R ⁴ and R ⁴ are independently selected from C1-C6 alkylene groups. In some exemplary embodiments, the cationizing agent is to[(3-chloro-2- hydroxypropyl dialkylammonium)alkyl] ether dichloride, 6/.s|(3-chloro-2- hydroxypropylmethylethyl-ammonium)propyl] ether di chloride, or combination thereof. Other suitable cationizing agents can be found in U.S. Pat. Pub. No. 2015/0210627, which is incorporated herein by reference in its entirety.

[0035] It is contemplated that the cationizing agent may be present in the activated dye mixture at a concentration of from about 10 g/L to about 150 g/L, about 20 g/L to about 140 g/L, or about 40 g/L to about 110 g/L. Said differently, the cationizing agent may be present in the activated dye mixture at a concentration of at least 20 g/L, 25 g/L, 30 g/L, 35 g/L, 40 g/L, 45 g/L, 50 g/L, 55 g/L, 60 g/L, 65 g/L, 70 g/L, 75 g/L, 80 g/L, 90 g/L, 100 g/L, 105 g/L, 110 g/L, 115 g/L, 120 g/L, 125 g/L, 130 g/L, 135 g/L, or 140 g/L.

[0036] The concentration of cationizing agent can also be expressed in terms of molarity. It is contemplated that the cationizing agent may be present in the activated dye mixture at a molarity of from about 0.01 molar to about 1.5 molar, about 0.05 molar to about 1, or about 0.1 molar to about 0.5. Said differently, the cationizing agent may be present in the activated dye mixture at a molarity of at least 0.01 molar, 0.05 molar, 0.1 molar, 0.15 molar, 0.2 molar, 0.25 molar, 0.3 molar, 0.35 molar, 0.4 molar, 0.45 molar, 0.5 molar, 0.55 molar, 0.6 molar, 0.65 molar, 0.7 molar, 0.75 molar, 0.8 molar, 0.85 molar, 0.9 molar, 0.95 molar, 1 molar, 1.1 molar, 1.2 molar, 1.3 molar, or 1.4 molar.

[0037] Referring now to the base, the base when used in conjunction with the methods of the disclosure can promote cationization of the cellulosic material by dehalogenating and deprotonating the cationizing agent to form a reactive glycidyl (epoxy) intermediate compound which in turn can react with hydroxyl groups of the cellulosic material. In various embodiments, the base may be selected from the group of sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium hydrogen carbonate, potassium carbonate, potassium phosphate, potassium silicate, sodium silicate, sodium phosphate, and combinations thereof. Exemplary bases include alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide.

[0038] The amount of base used can be dependent on the type and amount of cationizing agent, and the methods utilized for forming the dyed cellulosic material. For example, it is to be appreciated that a mono-quantized cationizing agent may use more base as compared to a diquantized cationizing agent. It is contemplated that the base may be present in the activated dye mixture at a concentration of from about 1 g/L to about 100 g/L, about 15 g/L to about 60 g/L, or about 20 g/L to about 55 g/L. Said differently, the base may be present in the activated dye mixture at a concentration of at least 1 g/L, 5 g/L, 10 g/L, 15 g/L, 20 g/L, 25 g/L, 30 g/L, 35 g/L, 40 g/L, 45 g/L, 50 g/L, 55 g/L, 60 g/L, 65 g/L, 70 g/L, 75 g/L, 80 g/L, 85 g/L, 90 g/L, 95 g/L.

[0039] Expressed in terms of molarity, it is contemplated that the base may be present in the activated dye mixture at a molarity of from about 0.05 molar to about 2 molar, about 0.25 molar to about 1.5 molar, or about 0.35 molar to about 1.375 molar. Said differently, the base may be present in the activated dye mixture at a molarity of at least about 0.05 molar, 0.1 molar, 0.15 molar, 0.2 molar, 0.25 molar, 0.3 molar, 0.35 molar, 0.4 molar, 0.45 molar, 0.5 molar, 0.55 molar, 0.6 molar, 0.65 molar, 0.7 molar, 0.75 molar, 0.8 molar, 0.85 molar, 0.9 molar, 1 molar, 1.05 molar, 1.1 molar, 1.15 molar, 1.2 molar, 1.25 molar, 1.3 molar, 1.35 molar, 1.4 molar, 1.45 molar, 1.5 molar, 1.6 molar, 1.7 molar, 1.8 molar, or 1.9 molar. [0040] The amounts of base and cationizing agent utilized can also be described with reference to the molar ratio of the base to the cationizing agent. It is contemplated that the molar ratio of the base to the cationizing agent is in a range from about 1 : 1 to about 8:1.

[0041] Referring now to the reactive dye, the method described herein along with its dye mixtures can utilize a variety of dyes and therefore provide good flexibility for color offerings. The activated dye mixture when utilized according to the methods described herein can provide improved dye association by virtue of chemical interaction between the positively charged quatemized nitrogens of the cellulosic material-bound cationizing agent (e.g., anionic groups of an anionic dye). In various embodiments, the reactive dye is an anionic reactive dye. However, the method described herein along with its dye mixtures can also accept other dye types that associate the dye with the cellulosic material in a manner that does not rely on the cellulosic material-bound cationizing agent, such as natural dyes, basic (cationic) dyes, sulfur dyes, pigment dyes, and vat dyes.

[0042] Anionic reactive dyes can include one or more anionic groups, such as sulfonate or carboxylate groups. For example, the anionic reactive dye can include one or more sodium sulfonate (-SChNa) groups. The one or more anionic groups can be present in a dye molecule cable of absorbing light in the visible spectrum and having at least one chromophore/col orbearing group with a conjugated system. Commonly used anionic dyes include those based on azo chemistries, anthraquinone chemistries, and triphenyl methane chemistries. Azo dyes are chemically characterized by the group R-N=N-R’, where R and R’ commonly include an aryl group, with various chemical substituents attached to the aryl groups. Other anionic dyes include those having nitro chemistries, azine chemistries, and quinoline chemistries. Acid dyes are a type of anionic dyes that can include acid groups such as carboxylic acid, sulfonic acid, or phosphoric acid groups. Anionic dyes that can be used in methods of the disclosure are described in various references, such as Ashland, J.R., (1997) Textile Dyeing and Coloration, American Association of Textile Chemists and Colorists, AATCC; Rnutson, L. (1986) Synthetic Dyes for Natural Fiber, Interweave Press; Revised edition, which is incorporated by reference in its entirety. Non-limiting examples of suitable anionic reactive dyes include acid dyes described as “C.I. Acid” in Colour Index, direct dyes described as “C.I. Direct” in the same, and reactive dyes described as “C.I. Reactive” in the same, such as C.I. Acid Yellows 17, 49, 67, 72, 127, 110, 135 and 161, C.I. Acid Reds 37, 50, 111, 114, 257, 266 and 317, C.I. Acid Blues 41, 83, 90, 113, 129 182 and 125, C.I. Acid Oranges 7 and 56, C.I. Acid Greens 25 and 41, C.I. Acid Violets 97, 27, 28 and 48, etc.

[0043] The amount of reactive dye used can be dependent on the type and amount of cationizing agent, the type of reactive dye, the intensity of the desired color, and the methods utilized for forming the dyed cellulosic material. The anionic reactive dye may be present in the activated dyeing mixture at a concentration of from about 0.001 g/L to about 5.0 g/L, about 0.005 g/L to about 4 g/L, or about 0.01 to about 2 g/L, with more concentrated mixtures providing a more intense dye color to the cellulosic material. It is to be appreciated that when greater color strengths are desired, the amount of the cationizing agent in the activated dye mixture should be adjusted to provide the desired cationization of the cellulosic material for binding of the reactive dye thereto. The molar ratio of the reactive dye to the cationizing agent may be in a range from 1:1 to 1.5:1.

[0044] Referring now to the cellulosic material, the cellulosic material which can include modified cellulose, as well as chitin and derivatives thereof, have chemistries that allow reaction with the cationizing agent. Cellulose is composed of repeating glucopyranose subunits which presents three hydroxyl groups on each subunit. Cellulosic materials also include rayon (viscose), which is generated from wood pulp, and lyocell (e.g., Tencel™), which is a form of rayon. Cellulosic materials treated according to the disclosure can also include cellulose derivatives such as cellulose acetate, or imidazolidinone-modified cellulose. The cellulosic material can be a blend or mixture of different materials, such as a blend of natural and synthetic fibers. Blends include blends of different types of natural fibers, such as wool/cotton blends, silk/cotton blends, and angora/cotton blends. Animal-based materials can include collagen fibers, keratin fibers, fibroin fibers, or a mixture thereof. Other exemplary blends include blends of cellulosic and synthetic fibers, such as cotton/polyester blends, cotton/ polyolefin blends, cotton/polyacrylonitrile blends, cotton/polyamide blends (e.g, cotton/nylon blends), as well as blends of cellulose fibers and cellulose derivative fibers, such as cotton/rayon blends. In various embodiments, the cellulosic material includes cotton, rayon, bamboo, hemp, or combinations thereof.

[0045] With reference to FIGS. 1-7, the method may be continuous process wherein the cellulosic material is fed into a treatment bath including the activated dye mixture within 60 seconds after forming the activated dye mixture, is moved through the bath, and is then removed from the bath. As described above, the cellulosic material is fed into a treatment bath including the activated dye mixture within 55, 50, 45, 40 ,35, 30, 25, 20, 15, 10, or 5 after forming the activated dye mixture. In certain embodiments, this “padding step” can be performed quickly. For example, the residence time (“padding times”) in the padding bath is defined by the time where a particular portion of the cellulosic material enters the bath and then ends when that particular portion leaves the padding bath. Typically, this is greater than 0.5 second, greater than 1 second, or greater than 2 seconds, and generally less than 1 minute, about 45 seconds or less, or about 30 seconds or less. An exemplary padding time is in the range of from about 1 second to about 1 minute, about 1 second to about 45 seconds, about 1 second to about 30 seconds, about 1 second to about 20 seconds, about 1 second to about 15 seconds, about 1 second to about 10 seconds, or about 2 seconds to about 5 seconds.

[0046] In various embodiments, the residence time of the cellulosic material in the treatment bath can be determined by the speed of the machine as well as other aspects of the system utilized. For example, based on the rate that the textile conveyor apparatus of the system moves the cellulosic material through the treatment bath, and the length of the travel path through the treatment bath, the residence time of the textile in the treatment bath can be known.

[0047] The padding process can result in the cellulosic material becoming “soaked” or “saturated” with the activated dye mixture. In some modes of practice, as the dyed cellulosic material exits the bath, excess activated dye mixture can be removed from the dyed cellulosic material and disposed of. In contrast to conventional methods wherein the treatment solution can be reused, the activated dye mixture must be contacted with the cellulosic material within 60 seconds after forming the activated dye mixture and thus any contact of the excess activated dye mixture with additional cellulosic material would likely be after 60 seconds after forming the activated dye mixture.

[0048] After forming the dyed cellulosic material, the method may further include the step of allowing the dyed cellulosic material to cure for no greater than 18 hours, 17 hours, 16 hours, 15 hours, 14 hours, 13 hours, 12 hours, 11 hours, 10 hours, 9 hours, 8 hours, 7 hours, or 6 hours, before washing the dyed cellulosic material. The dyed cellulosic material may be cured utilized any method known in the art for curing cationic agents and dyes on cellulosic materials. In some embodiments, the dyed cellulosic material is wound on a beam and held for a period of time (e.g., no greater than 18 hours) to allow the dye to react with the cationized cellulosic material. However, it is to be appreciated that the step of curing may include a step of heating, such as by steam or an elevated air temperature. [0049] After allowing the dyed cellulosic material to cure, the method may further include the step of washing the dyed cellulosic material. The dyed cellulosic material can be washed with any aqueous or non-aqueous solution (c.g. a hot aqueous solution). The wash solution can remove at least a portion of any unreacted or hydrolyzed cationizing agent, base, dye, or other optional component (e.g, viscosity enhancers) carried over from the treatment bath.

[0050] In further aspects of the inventive subject matter, when the fabric is put through the dyer after the curing process, Hoffman Degradation and volatile amine (e.g, trimethylamine) formation is often observed. To reduce or even entirely eliminate such degradation, addition of a guanidinium phosphate, modified to have increased nucleophilicity, to CHPTAC treated cotton will prevent the release of trimethylamine upon heat exposure. Advantageously, use of such modified guanidinium phosphate will enable CHPTAC treatment of cellulosic materials and so allow for significantly improved dying performance with substantially reduced production of waste materials.

[0051] In some embodiments, the modified guanidinium phosphate has a structure according to Formula III:

NHR

H ₂ NCNH _{2 i} wherein R is a radical that increases the nucleophilicity. Thus, and viewed from a different perspective, R will be a radical having a +M (positive mesomeric) and/or +1 (positive inductive) effect. For example, suitable R groups therefore include hydrogen, an alkyl group (preferably lower alkyl with 1-6 carbon atoms), an alkoxide (e.g, methoxy, ethoxy, propoxy), an alcohol group, a primary or secondary amine (typically substituted with lower lower alkyl), or an aryl or heteroaryl group (preferably a 5- or 6-membered ring system). Of course, it should be appreciated that the Hofmann elimination inhibitor may also comprise at least two distinct guanidinium phosphates.

[0052] With respect to suitable fibers it is contemplated that all fibers are suitable that can be treated with CHPTAC to so introduce cationic groups to the fiber. Therefore, contemplated fibers include all fibers with vicinal hydroxy groups, and particularly cellulosic fibers of natural and/or synthetic origin. [0053] As will be readily appreciated, the quantity of Hofmann elimination inhibitors will vary depending on a number of factors, including the type and proportion of cellulosic fibers in the material to be treated, the amount of CHPTAC used, the amount of dye introduced, etc. Furthermore, it should be noted that while CHPTAC is the preferred actionizing agent, various cationizing agents other than CHPTAC are also deemed suitable and include numerous reactive quaternary ammonium compounds that can bind to cellulosic fibers.

[0054] Likewise, it should be recognized that the reaction conditions of the Hofmann elimination inhibitor with the treated fiber may vary considerably. However, it is generally preferred that the Hofmann elimination inhibitor will be allowed to react for at least 10 seconds, or at least 30 seconds, or at least 2 minutes, or more with the treated fibers. Reaction temperatures will generally be at elevated temperatures, typically at least 60 °C, or at least 80 °C, or at least 100 °C, or at least 120 °C, or higher.

[0055] For example, in one typical use CHPTAC treated cotton (produced in a conventional treatment process) is padded with 2 g/L of the guanidinium phosphate of Formula I and then heated at 140-160 °C in a tenter frame at 35-45 meters per minute. Remarkably, no trimethylamine odor is produced when the Hofmann elimination inhibitor is used, whereas a strong odor of trimethylamine is produced when the Hofmann elimination inhibitor (e.g., modified guanidinium phosphate of Formula III is not present.

[0056] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.

[0057] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0058] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. As also used herein, and unless the context dictates otherwise, the term "coupled to" is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms "coupled to" and "coupled with" are used synonymously.

[0059] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the scope of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C .... and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.