CN1488016A - Process for the production of protein sheaths surrounding textile fibers and textiles produced therefrom - Google Patents

Abstract

The present invention relates to a method of treating a synthetic, man-made or natural fibrous substrate to produce a permanently adherent proteinaceous sheath surrounding the individual fibers of the substrate. This treatment results in a composite matrix exhibiting the most desirable characteristics of a fibrous core with the most desirable characteristics of a proteinaceous sheath. The technique can also be applied to individual synthetic fibers or yarns, if desired, prior to weaving, knitting, stitchbonding or other method of woven or nonwoven substrate formation.

Description

Process for the production of protein sheaths surrounding textile fibers and textiles produced therefrom

Background of the invention

In recent years, particularly in apparel, consumers have reduced the use of synthetic fabrics and blends in favor of 100% woolen fabrics that provide the best appearance and comfort. But the use of woolen yarns and fabrics also has its disadvantages. First, fabrics made entirely from natural wool tend to shrink and feel when washed, so they must be dry cleaned, not washed, which is expensive and requires the use of carcinogenic solvents. Additionally, these fabrics are not as wrinkle-resistant as synthetic fabrics. The most common method of controlling wool shrinkage, felting and wrinkling in outer garments is to react wool fabric with a resin made from formaldehyde and coat the fabric with a "lubricant" polymer to reduce felting. But consider formaldehyde to be a harmful chemical and dangerous to handle during processing. Since formaldehyde is a known carcinogen, it is also considered dangerous for fabrics that come into contact with the body. Additionally, formaldehyde-based resins, when used to control shrinkage and felting of wool or wool-blend fabrics, can reduce the abrasion resistance and strength properties of the fabrics and make them more prone to holes and wrinkle deformation. Although formaldehyde-free resins such as polycarboxylates have been invented, they are less effective, more expensive and equally prone to loss of fabric strength. Adding a "lubricating" polymer also changes the hand of the fabric, resulting in a hand more similar to synthetic fabrics. Because of these problems, few commercially produced wool fabrics are treated to control shrinkage, felting and wrinkling.

With the advent of synthetic textile fibers such as polyester, polyamide, polyacrylamide, polyolefin, polyacrylate, and nylon, production is stronger and more durable than those formed from staple fibers, with less Continuous filaments have increased potential for wrinkling and shrinkage problems. Shrinkage of these fabrics can be controlled by using the yarn beyond the heat treatment point of the synthetic fiber polymer. Products manufactured from synthetic yarns have excellent strength properties, dimensional stability and good color fastnesses to washing, dry cleaning and light exposure. Knitted and woven fabrics using 100% polyester were very popular in the late 1960's and throughout the 1970's. More recently, continuous filament polyester fibers have also been cut into staple fibers which can then be spun into 100% staple yarn or blended with wool or other natural fibers. But synthetic yarns and fabrics made from them suffer from a number of undesirable properties, including a shiny synthetic appearance, slippery artificial feel, limited moisture vapor transfer capability, and a tendency to build up static charges. In addition, polyester fibers in staple form are prone to pilling and polyester fibers in continuous filament form are prone to picking.

Some attempts have been made to produce fabrics that have the positive properties of both wool and polyester fibers without their negative properties. Such attempts include blending and sheath/core yarn spinning. These methods require fiber/yarn modification, but until the present invention, fabric modification was not possible.

Conventional methods of blending wool with synthetic fibers have not been entirely successful because mechanical and direct blends of polyester and wool tend to pill, block, shrink, and can be uncomfortable to wear. In recent years, particularly in apparel, consumers have rejected the use of polyester and polyester blends in favor of 100% wool fabrics that provide the best appearance and comfort.

US Patent No. 5,622,531 discloses that in order to increase the hydrophilicity of polyurethane fabrics, chitosan is used as an adhesive layer to coat water-soluble wool protein onto polyurethane fabrics. This method is specific to polyurethane, and does not attempt to form covalent bonds between textile, chitosan or wool protein layers, ie use only weak non-covalent forces, to fix the protein layer to polyurethane.

Therefore, there is a need in the art to produce fabrics that have the positive properties of both wool and synthetic fibers while eliminating the negative properties of each. The method is also fast, economical, durable, and applicable to many types of fabrics, and is readily apparent to current textile manufacturing practices such as sanding, weaving, and dyeing.

Summary of the invention

The present invention relates to a method of treating a fabric, garment, woven or nonwoven (herein included within the term "substrate" or "fibrous substrate") made of synthetic fibers to produce a permanently adhered Protein crust. Proteins have the desired properties for wool formed from proteins. This treatment results in a composite matrix that exhibits the most desirable characteristics of a synthetic core while having the most desirable surface characteristics of a natural, proteinaceous sheath. For example, it will exhibit the mechanical properties of a synthetic core fiber and wool-like surface properties. It is also possible to apply this technique to individual synthetic fibers or yarns before weaving, if desired.

More particularly, in the method of the present invention, an article or fibrous substrate comprising synthetic hydrophobic fibers is contacted with an aqueous solution comprising water-soluble (oxidized) protein polymers or monomers. The protein monomers/polymers are then reduced and/or crosslinked to each other and to the fibers using a suitable crosslinking agent to form a durable protein sheath or envelope around the hydrophobic fibers. The resulting composite synthetic matrix exhibits the desirable properties of proteins (e.g., non-sparkly appearance, wool-like feel, water absorption and breathability, comfortable feel close to the skin, etc.), while maintaining the desirable properties of synthetic materials (e.g., strength, Good color fastness and no shrinkage or wrinkling), even after repeated washings. An advantage of this method is the ability to apply it directly to dyed and finished synthetic fibers by performing a padding/drying/curing process, which is economical and readily achievable with currently used textile equipment.

The present invention further relates to methods of treating fabrics, garments, woven or non-woven fabrics ("substrates" or "fibrous substrates") or individual natural fibers or yarns made from natural fibers to create permanent adhesion around the fibers of the substrate protein coat or envelope. This imparts the desirable properties of a cotton-like surface while retaining some of the functional properties of the natural fiber core.

According to the present invention, other components may be incorporated into the envelope layer to impart durability to synthetic or natural fibers or fabrics. In this way, the protein layer acts as a binder, encapsulating not only the matrix fibers, but also the compounds incorporated into the outer layer.

Detailed description of the invention

As used herein and in the appended claims, "a" means "one or more".

In a preferred embodiment of the invention, a synthetic, artificial or natural core material in the form of a fabric or other fibrous matrix is subjected to an aqueous solution containing a water-soluble (oxidized) protein and a cross-linking agent and optionally a suitable cross-linking agent catalyst. dye bath. This dyebath is referred to herein as a "protein polymer sheath formulation" or "sheath formulation". The fabric or substrate is padded, excess bath is removed, heated to dryness, and then cured at a temperature sufficient to cause a reaction between the crosslinking agent, core material, and protein. Crosslinks are formed between these compounds, resulting in the formation of a protein film on the surface of the core. This layer is referred to herein as the "protein envelope", "protein coat", "coat layer" or "skin". This same general approach can also be applied to individual fibers, ribbons and molding materials. This application is accomplished by contacting the substrate with the treatment solution by spraying, foaming or any other means known in the art. Alternatively, the fabric can be dipped first in a dyebath containing solubilized protein and a crosslinking agent, and then optionally sprayed or dipped in a second dyebath containing an acidic reducing agent to regenerate the initial insoluble protein structure.

Non-limiting examples of water-soluble protein polymers include chemically oxidized wool, gelatin, sericin, albumin, collagen, and the like.

Water-soluble protein polymers are prepared by oxidative denaturation of proteins such as wool, for example in a slightly alkaline liquid medium containing an oxidizing agent. The liquid medium is preferably an aqueous medium, but alcohols such as methanol, ethanol or the like may be used alone or in combination with water. The liquid medium is made slightly alkaline by adding a pH adjusting agent selected from, but not limited to, ammonia, alkali metal hydroxides, amines, alkali metal carbonates, and the like. These can be appropriately selected according to the kind of liquid medium and the oxidizing agent to be used.

Examples of oxidizing agents are well known in the art, but are not limited to peroxides such as hydrogen peroxide, peracetic acid, performic acid, and the like. Hydrogen peroxide is currently preferred because it is cheap, easy to control and easy to dispose of to destroy excess hazardous waste.

The rate of protein dissolution varies with the protein, the type and concentration of the oxidizing agent, and the type of dissolution medium used. Dissolution times are generally from about 0.1 to about 1.0 hours. The resulting solubilized protein contains the functional groups of its constituent amino acids, such as hydroxyl, amine, and carboxylate groups, and the protein can be used with cross-linking agents so that the protein covalently sticks to itself, making the protein coat durable Adhesively bonds to synthetic, man-made or natural fibers.

Any compound capable of binding to two or more nucleophilic components (e.g. hydroxyls, amines, thiols, etc.) , amine and carboxylate groups attached to a synthetic or artificial core. Presently preferred crosslinking agents are epoxides. Epoxide crosslinkers include epichlorohydrin, polyethylene glycol-diepoxide terminated, or any other monomer or polymer containing two or more epoxy groups. These species react with nucleophilic groups, preferably amines and thiols. Those skilled in the art are familiar with many more crosslinking chemistries than those listed here. For example, blocked isocyanates or crosslinkable silicone polymers may be used. Polycarboxylic acids and methylol compounds can be used in a two-step impregnation process. That is, it is not possible to use methylol compounds and polycarboxylic acids in the same solution as alkaline oxidized wool because they require acidic conditions for crosslinking, and the acid will cause precipitation of oxidized wool. However, the soluble wool can first be padded onto the substrate, after which the acidic methylol compound or polycarboxylic acid can be padded onto it - a two-step process. Epoxides, on the other hand, crosslink under alkaline conditions, so soluble wool and epoxy crosslinkers can be placed together in the same dyebath.

Although there are many crosslinking chemistries that make it possible to form a sheath of protein polymers around the fibers, the following methods are currently preferred: epoxy in a one-step impregnation process; in a two-step impregnation process, with or without hypophosphorous acid Anhydride chemicals (such as polycarboxylic acids) with sodium catalysts; and N-methylol compounds (such as DMDHEU) with magnesium chloride catalysts in a two-step impregnation process.

The temperature of the processing solution to oxidize the protein and crosslinker should not be so high as to decompose the reactants or so low as to cause inhibition of the reaction or freezing of the solvent. The time required for the crosslinking process here will depend largely on the temperature employed and the relative reactivity of the starting materials. Thus, the time the textile is exposed to the oxidized polymer in solution can vary widely, for example from about 1 second to about 2 hours. Exposure times are typically from about 5 to about 10 seconds. After exposure, the treated yarn or fabric is dried at ambient temperature or at a temperature above ambient temperature, up to about 100°C. If no polymerization takes place during the drying step, the fabric is cured after drying. Unless contradicted by specification, the methods described herein are carried out at atmospheric pressure, at a temperature from about 80°C to about 180°C, more preferably from about 110°C to about 160°C, and most preferably at about 150°C. Unless otherwise stated, process times and conditions are intended to be approximate.

The present invention further relates to hydrophobic yarns, fibres, fabrics, finished articles or other textiles (included herein under the terms "textile", "substrate" and "fibrous substrate") treated with the proteinaceous fabric finishes of the present invention. These textiles or substrates exhibit improved moisture absorption and permeability compared to conventional synthetic and some man-made textiles. In addition, other properties of the fibers, such as fiber luster, fabric feel or "hand", static dissipative capabilities, and fiber-to-fiber frictional noise characteristics, can be modified through treatments.

The properties conferred by the protein sheath or encapsulation do not interfere with the macroscopic properties of the fabric; that is, the sheath does not significantly increase the diameter of the fibers, it does not fill the spaces between fibers or clog the fabric with chunks of protein, etc. In addition, the treated fabric feels like wool, rather than polyester, and exhibits improved moisture absorption.

Synthetic and man-made textiles prepared according to the present invention can be used in many ways, including but not limited to clothing, upholstery and other furniture, hospital and other medical applications, automotive fields, etc.; and industrial applications, such as Adanue S., in Wellington Sears Handbook of Listed in Industrial Textiles, pages 8-11 (Technomic Publishing Co., Lancaster, PA, 1995).

Textiles in the form of clothing can be imparted with properties through processing, including soft hand, shrinkage control, durable ironing and extraordinary and unique appearance, depending on the process used. Lava stones, pumice stones, bleach, and/or protein kinases can be used to facilitate abrasion and give clothing a hardwearing appearance. These and similar post-processing methods can be applied in the present invention to improve the aesthetic appeal of the final garment. The protein sheath encapsulating the synthetic, man-made or natural fibers makes possible the application of post-treatment processing techniques to the treated synthetic, man-made or natural fabrics of the present invention.

Incorporation of auxiliary components into the cortex

According to the present invention, the application of the protein encapsulation layer to the fabric provides the opportunity to simultaneously finish the fabric with ancillary components which do not themselves have an inherent ability to durably bond to the fabric. In this manner, the protein sheath acts as a binder, imparting durability to non-essential adjunct components co-coated with the sheath finish. Alternatively, the adjunct component may have an affinity for the protein finish, and the adjunct component may be applied during processing after the protein encapsulant is applied. In another approach, the base fabric has many properties that would not be possible without the use of an encapsulating layer.

Some examples of auxiliary components include infrared absorbing compounds that can be permanently incorporated into the fabric to minimize detection from night vision devices. Examples of infrared absorbing materials are carbon black, chitin resins, or compounds that generally absorb electromagnetic radiation at a wavelength of 1000 to 1200 nm. Fabrics treated with an envelope comprising an infrared absorbing material that develops infrared absorbing capabilities, as well as other beneficial properties pertaining to the envelope, may be particularly beneficial in military applications.

Similarly, UV light shielding compounds may also be incorporated to protect the wearer of the garment or the fabric material itself from UV light. Colored pigments or dyes may be incorporated into the outer layer to dye the fabric. Magnetic colloids can be embedded within the skin to provide data storage capabilities to the fabric. Bioactive agents such as insect repellents, antimicrobials, and pharmaceuticals can also be incorporated, as well as flame retardant chemicals and antistatic agents. According to the invention, it is also possible to use odor-absorbing compounds and neutralizing agents such as activated charcoal or cyclodextrins or materials whose release in a long-term manner is desired, for example by using hydrolysable linkers.

In one embodiment, colloids (generally described as particles having an average diameter of 10 to 500 nanometers) are incorporated into the encapsulated sheath formulation and bonded to the treated fabric. The colloidal particles are too small to be observed with a conventional microscope, and as a result individual particles will not be noticeable on the fabric. But some metal colloids such as gold and silver are of particular interest due to their light-absorbing properties. Metal colloids absorb light at the wavelength of maximum absorption, which is related to the type and particle size of the metal. They have a wide range of uses in inventions involving biological and toxicological analyses.

US Patent 5,851,777 to Hunter et al. discloses the use of colloidal particles bound to ligands specifically attached to some biological or toxicological moiety. Colored metal colloids are specifically claimed as an aspect of this invention. When a specific biological or toxicological moiety is added to a solution containing ligand-bound metal colloidal particles, coordination with this moiety results in particle aggregation and a shift in the wavelength of maximum absorption (ie, solution color). Hunter et al. also disclose a number of related patents in which ligand-bound colloidal particles are used. An important aspect of these inventions is the ability to attach ligands to the particle surface through an intermediate polymer. The intermediate polymer is either physically entrapped (partially) within the particle or durably absorbed onto the particle surface. The necessary intermediate polymer contains reactive groups that enable it to attach to the ligand. The disclosure in USP5851777 and those cited therein are incorporated herein by reference.

US Patent 6,136,044 to Todd discloses the use of metal colloids to color substrates such as fibers, yarns and textiles. The substrate to be colored is first placed in a dyebath containing a reducing agent, preferably an agent with a certain affinity for the substrate. After allowing sufficient time for the reducing agent to adsorb, the substrate is removed from the dyebath, optionally dried, and placed in a second dyebath containing dissolved metal salts corresponding to the metal colloids of interest. The adsorbed reducing agent reduces the salt to a colloid and acts as a nucleation site for particle growth. The resulting particles are adsorbed to or optionally entangled with a matrix. The substrate is thus colored with a shade adapted to the parameters of type of metal, grain size and amount of metal present on the substrate. Since each of these parameters can be controlled, various shades can be obtained. The resulting color of the substrate is both washfast and lightfast. This method does not require the use of polymeric binders or other agents to provide color fastness.

Some metal colloidal suspensions, particularly silver and copper, and more particularly silver, have demonstrated antimicrobial activity against a broad spectrum of bacterial species. The Merck Index (10th Edition) states that silver "has been used to purify drinking water because of its toxicity to bacteria and lower life forms".

In one embodiment of this aspect of the invention, metal colloids are incorporated into the sheath formulation to color the fibrous substrates treated with the formulation. In another embodiment of this aspect of the invention, metal colloids having antimicrobial activity, preferably silver and copper, most preferably silver, are incorporated into the skin formulation. Substrates treated with this formulation exhibit antimicrobial activity. In yet another embodiment of this aspect of the invention, metal colloids are incorporated into the sheath formulation in an amount sufficient to promote electrical conductivity on the surface of the treated substrate, while the untreated substrate has little or no electrical conductivity. sex. The treated substrate thus has antistatic properties.

Metal colloids can be incorporated into the skin formulation by various methods. In one approach, a metal colloid is prepared and then added to the skin formulation. Metal colloids can be prepared by reduction of metal salts by chemical, electrochemical or radiation methods known in the art. For example, silver salts can be reduced to metallic silver with sodium borohydride (chemistry), potential (electrochemistry), or with visible light (radiation). So-called "purifying agents" can be used within the metal colloid formulation; these agents can act as nucleating agents for particle growth, and can also coat the particle surface to minimize particle aggregation. Common passivating agents include bovine serum albumin, casein, and milk proteins (such as milk powder). The passivating agent preferably contains functional groups that react with components in the sheath formulation. More preferably, the deactivating agent is physically entrapped within the colloidal particle to facilitate entrapment of the colloidal particle within the cortex.

Metal colloids can also be prepared directly in the sheath formulation solution or together with one or more components. Colloid formation is initiated by mixing the soluble metal salt of the colloid of interest with between one and all of the skin formulation components and then exposing to reducing conditions. A potential advantage offered by this approach is that a viscous solution of between one to all of the skin formulation components prevents aggregation of adjacent colloidal particles. In addition, one or more components of the skin formulation may act as deactivators for the colloidal particles.

Incorporation of colorants

In another embodiment, the present invention may be used as a binder to fix the colorant to the fibers. As used herein and in the appended claims, the term "colorant" means either a pigment (water insoluble) or a dye (water soluble).

Although one of the main purposes of protein-encapsulated finishes is to give synthetic fibers the feel of a "natural fiber" such as wool, the treated fibers have completely different chemical and physical properties than wool fibers. There are at least three important differences:

First, the materials that make up the finish may only be chemically similar to, but different from, wool fibres. Chemical differences have a significant impact on the efficiency of the various dyes.

Second, the cortex is highly cross-linked and thus tightly entangled with the parent fibers. The skin is unlikely to have a significant ability to swell in water, and if it did, it would not be washable. Conventional dyeing relies heavily on swelling of the fibers, allowing the dye to absorb into the fibers; this maximizes both fastness and depth of shade. Dyeing sheathed fabrics may not be effective using conventional techniques that rely on fiber swelling.

Third, the cortex is very thin relative to the thickness of the fibers. In the absence of concomitant dyeing of the core fiber, the best uniform dyeing throughout the sheath produces only a ring dyeing effect on all fibers; many core fibers have affinity for only a limited class of dyes, so when used with no affinity for core Ring dyeing is generally observed when the cortex is stained with neutral dyes.

The colorant can be selected to match the color of the core fiber for a darker shade, or it can be selected as a different shade for a "two-tone" effect. Most likely, though not necessarily, the colorant may be selected as a dark shade on top of the lighter colored core fiber. The result will be a "ring" dyed fabric. Such dyeing is not readily available on synthetic fibers, but is facilitated by the invention described herein. In one embodiment of the invention, the pigment is dispersed within or co-coated with the encapsulated sheath. Another embodiment of the "two-tone" invention would have a separate dyeing step in the processing of the textile. The core fiber (dyed or undyed) is treated with a protein sheath, and the fabric is subsequently dyed with a dye that has an affinity for the sheath. The dye will be selected so that it reacts or adheres to the outer surface, but not the inner core, or vice versa. For example, polyester fibers treated with a protein sheath can be selectively dyed with dyes specific to polyester for coloring of the inner core (or not dyed for white) and dyes specific to proteins to dye the outer layers. Some common dyes for outer layers include: a) dyes that absorb physically (acid dyes); b) dyes that will be retained mechanically (vat and sulfur dyes); or c) dyes that will chemically react on the protein surface (reactive dyes). dye). This technique provides a way to create a variety of effects and colors. Frosted (lighter color over darker upper), duotone (two different colours) and "worn" (optionally abraded or hydrolyzed outer layers, giving a worn look) effects are all possible with the present invention. possible.

coloring method

As used herein, the terms "one-step" and "multi-step" refer to the number of steps required to process a fabric or substrate to provide a colored skin. The "one step" method may require several steps before the substrate is involved, but the colorant and sheath will be applied to the fabric at the same time. In a multi-step process, the colorant and skin are applied in separate steps.

One-Step Method: The easiest method is to incorporate the colorant into the base protein sheath formulation before the finish is applied to the fabric. The pigmented formulation is then applied according to conventional methods such as dipping, spraying or padding, with the latter method being preferred. The colorant is retained within the sheath by means such as physical entanglement or encapsulation, electrostatic coordination, or chemical bonding to the sheath material. In addition to the ease of processing, another advantage offered by this method is the depth of shade that can be achieved. The cortex is at most 10 times smaller than the thickness of the fabric fibers it encapsulates, and possibly even smaller. Evenly distributing the colorant throughout the cortex maximizes the amount of colorant applied. Even distribution also helps ensure that the colorant is "colorfast" or not easily removed by washing or other abrasive conditions. Potential disadvantages may include lack of equipment during the finishing process and/or difficulty applying the colorant within the textile mill, difficulty achieving uniform application and depth of shade during the padding process, and cleaning and disposal issues with pigmented sheath finishes.

Multi-step method: In this method, the colorant is applied to fabric that has been previously finished with a base protein sheath formula. The applied formulation may optionally include components having a specific affinity for the colorant. Alternatively, the finished fabric may be treated with a component that has an affinity for both the skin and the colorant prior to exposure to the colorant. A potential advantage of this approach is the use of colorants that would not be possible to incorporate into the skin formulation without altering the stability or durability of the skin. Another advantage compared to the one-step process is that significant aesthetic results can be achieved. Disadvantages include limitation in the types of colorants that are effective and possible surface aggregation of colorants, with color problems associated with poor depth of shade, crockfastness, and color fastness. The cortex is tightly cross-linked, which prevents colorants from penetrating the cortex to any appreciable depth.

The following are some specific illustrations of methods of coloring with known dyes. One or both of the methods described above can be applied to these methods.

Mordant fixation: Some metallic species called mordants form strong chemical bonds with chemically reactive groups such as carboxylate and phenolic functionalities; the resulting mordant complexes do not dissociate in water and are often water insoluble. Because of the mordant-reactive chemical groups found on many classes of dyes, mordant complexation provides a means of immobilizing insoluble dyes on or in a substance, especially when the substance is also complexed with the mordant metal . Mordant metals include chromium, cobalt, nickel, aluminum and zirconium.

In a one-step embodiment, a mordant and a mordant-reactive dye are mixed into the base protein skin formulation. The mordants and mordant-reactive dyes are mixed into the resulting coloring formulation in amounts, in an order and in a manner conducive to the desired properties of the formulation. Preferably, the resulting formulation is stable, eg the mordant complex does not precipitate out. Stability is facilitated by the coordination of mordants to reactive groups on the water-soluble polymers of the base skin formulation. But if the base skin formulation is sufficiently viscous, the mordant complex can be adequately suspended within the formulation and water solubility may not be required. The mordant is added in any desired amount up to an amount destabilizing aggregation within the base skin formulation. Dye is added as needed, up to the amount that can fully utilize the binding capacity of the mordant added. The pigmented skin formulation is then applied to the substrate, and the treated substrate is cured, thereby holding the skin in place. The dye is durably incorporated within the cortex by mordant complexation and by physical encapsulation.

In a multi-step embodiment, the mordant is mixed into the base protein sheath formulation in an amount and in a manner that facilitates the desired properties of the resulting mordant-modified formulation. The mordant preferably forms a bond with the sheath material, but in any case the resulting formulation is stable, eg the mordant complex does not precipitate out. Stability is facilitated by the coordination of mordants to reactive groups on the water-soluble polymers of the base skin formulation. But if the base skin formulation is sufficiently viscous, the mordant complex can be adequately suspended within the formulation and water solubility may not be required. The mordant is added in any desired amount up to an amount destabilizing aggregation within the base skin formulation. The mordant-modified formulation is then applied to the substrate, and the treated substrate is allowed to cure, thereby fixing the skin in place. The sheathed substrate is then exposed to the mordant-reactive dye by techniques known to those skilled in the art. In a preferred method, the substrate is exposed to a solution containing the dye at a temperature and for a period of time that facilitates complexation of the reactive groups on the dye with the metal-complexed mordant incorporated into the sheath. The dyed substrate is then dried. The dye is durably bound to the cortex by mordant complexation, but it is believed that the dye is only bound to the outer layer of the cortex due to tight crosslinking within the cortex.

In another multi-step embodiment, the sheathed substrate is exposed to a mordant-metal solution. The mordant metal exhausts onto the substrate by complexing with exposed reactive groups in the sheath material. The mordant-treated substrate is then removed from the solution, optionally dried, and then exposed to a solution containing the mordant-reactive dye. The dye is exhausted onto the cortex by complexing with the mordant on the surface of the cortex.

Other embodiments of such dyeing methods are readily apparent, and although not described, all such methods are considered to be within the scope of the present invention.

Pigments, Vat and Sulfur Dyes: Vat and sulfur dyes are hybrids between dyes and pigments that are typically used to dye cotton and other cellulose-based fibers. In their chemically reduced ("leuco") form, they are water-soluble dyes; but when oxidized, they become insoluble pigments. In conventional fiber dyeing, the fibers are exposed to a reduced form of the dye which facilitates the penetration of the dye into the fiber. The fibers are then exposed to oxidative conditions, which induce the formation of insoluble particles that are absorbed within the fibers. This hybridization behavior offers many ways in which these dyes can be used as colorants within skin formulations.

In a one-step process, pigments or oxidized vat or sulfur dyes are dispersed within a protein sheath formulation. Surfactants are optionally included to aid in dispersion. The viscous base coat formulation also helps aid in the longevity of the dispersion by slowing down the rate of settling. Colorants may be added in solid powder form or as aqueous dispersions. In both cases, and particularly for the latter, it is desirable that the addition of the colorant does not dilute the skin formulation to the point where the skin loses durability or is not effective in providing its performance when applied to a substrate. Aqueous dispersions of pigments are available from BASF under the trademark "HiFast ^™ ". The pigmented skin formulation is then applied to the substrate and cured in place. The colorant is dispersed throughout the cortex and retained in place by physical encapsulation.

In another one-step process, a leuco vat or sulfur dye solution is added to the skin formulation and the combined formulation is oxidized to form a dispersion of colorant within the skin formulation. Optionally, it may be necessary to adjust the pH of the pigmented crust formulation to within the specified values required for the base crust formulation. This method provides partial encapsulation of the outer skin polymeric material within the oxidized particle. As mentioned above, the viscous base coat formulation helps aid in the longevity of the dispersion by slowing down the sedimentation rate of the particles. The resulting dispersion is then applied to a substrate, followed by curing of the substrate to secure the skin. Encapsulated colorants are securely retained by physical entanglement.

In another one-step process, one or more sheath material components are added to a leuco, vat or sulfur dye solution. The components are preferably added in amounts equivalent to their weight percents in the base crust formulation. The added amount of the component is more preferably to significantly increase the viscosity of the solution. The leuco dye is then oxidized to form a dispersion of particles, preferably partially encapsulating the sheath material component. If necessary, add the remaining ingredients of the base skin formulation, and adjust the pH to the value specified for crosslinking. The pigmented formula is then applied to the substrate, and the substrate is cured to secure the skin. Encapsulated colorants are securely retained by physical entanglement.

Other embodiments of such dyeing methods are readily apparent, and although not described, all such methods are considered to be within the scope of the present invention.

Modified reactive dyeing: Commercially available reactive dyes are typically used to dye cotton and wool fibers. They contain functional groups that can react with nucleophilic sites at highly basic pH and elevated temperature. They have very good color fastness because the dye is covalently bound to the fiber. In the present invention, the sheath material may not include suitable reactive sites, or may not be applied at a highly alkaline pH, either of which would prevent reaction with commercial reactive dyes. Another challenge with using reactive dyes is hydrolysis of the active sites; hydrolysis competes with cellulose hydroxyl groups for dye reactivity and leads to ineffective dye application.

Various methods can be used to overcome the above difficulties. In one approach, the dye is first modified by reaction with a bifunctional reagent; one functional group of the reagent reacts with the dye and the other functional group binds to the sheath material. In a one-step process, the modified dye is then added to the base protein skin formulation, which can then be applied to the substrate. In another approach, a bifunctional reagent is added to the base skin formulation, the bifunctional reagent having one functional group that preferentially reacts with the reactive dye, the other functional group being bound to the skin material. The modified skin formulation is applied to the substrate and cured to fix the skin and bind the agent. The treated substrate is then dyed with a reactive dye that preferentially reacts with the remaining functional groups of the reagent in a multi-step process. In yet another approach, the sheath formulation incorporates one bifunctional agent, and the reactive dye is modified with a second bifunctional agent. Each of these two reagents contains at least one functional group which preferentially reacts with the functional group on the other reagent. In this case one-step or multi-step application can be used. Lewis and Vigo (Lewis, D.M., Lei, X; AATCC International Conference and Exhibition Book of Papers, Oct 4-7, 1992, pp. 259-265; Vigo, T.L., Blanchard, E.J.; AATCC International Conference and Exhibition Book of Papers, 1996, 203-208 pages; Vigo, T.L., Blanchard, E.J.; Textile Chemist and Colorist, vol 19, No.6 (1987); USP4678473) proposed similar ideas, but in these cases, the cellulose fibers were modified, rather than protein cortex.

Examples of functional groups that react preferentially with reactive dyes include amines and thiols, which are much more nucleophilic species than water, and can eliminate unwanted hydrolysis. Amines are more preferred. Examples of functional groups that can react with components in the protein skin include, but are not limited to, hydroxyl, amine, thiol, epoxide, and blocked isocyanate. Non-limiting examples of bifunctional reagents include ethylenediamine, ethanolamine, and glycidol.

Other embodiments of such dyeing methods are readily apparent, and although not described, all such methods are considered to be within the scope of the present invention.

Example

Experimental measurements:

Wetting Time: All wetting times are the average of six measurements. All times given are for complete absorption of a drop of distilled water placed on the sample. All times greater than 120 seconds were recorded and averaged 120 seconds. During the measurement, all samples were elevated so that neither the upper nor the lower surface of the samples touched the solid surface.

Embodiment 1; Preparation of wool protein solution

Wool fabric (7 kg) was placed in a water bath (100 L) of 30 wt% hydrogen peroxide, the pH of which was adjusted to 8 using aqueous ammonia. After 10 minutes, heat was generated sharply and foaming occurred naturally, and after 40 minutes, almost all wool fibers were completely dissolved. Traces of insoluble residue were removed by filtration. To the resulting solution was added 3% by weight of epichlorohydrin as a crosslinking agent, and the pH was adjusted to 9 with sodium borate.

Example 2; Treatment of Synthetic Fabrics

Sanded microdenier polyester (Burlington Industries, Greensboro, NC) was chosen as the synthetic matrix. The polyester was dipped in the protein solution obtained in Example 1, and padded to a liquid absorption of 40-50% and dried. The fabric was then sprayed with a 1 wt% sodium hydrosulfide reducing agent solution to 40% pick-up. The fabric was dried and cured at 350°F for 2 minutes. The fabric is then rinsed with hot water to remove unreacted chemicals and dried again. The resulting treated fabric has the same feel as wool and is not as shiny as the starting polyester. The wetting time to water was significantly improved (from >120 seconds before treatment to <10 seconds after treatment). Wash the fabric 20 times and still maintain the feel of wool and the wrinkle-free properties of polyester. It also does not shrink, feel, pill or lose its hydrophilicity.

Embodiment 3; Preparation of protein solution

By using dimethyloldihydroxyethylene urea (DMDHEU) crosslinker (Patcorez ^™ P-53, BF Goodrich) and wetting agent (WetAidNRW ^™ from BF Goodrich), detailed in the following examples The protein solution was prepared by dissolving granular gelatin (Acros Organics, a division of Fischer Scientific) in water at the concentration of . Keep the solution warm (>30°C) during use.

Example 4; Protein Solution Application to Woven 100% Polyester Fabric

A solution containing 10 wt% gelatin, 5 wt% DMDHEU and 0.1 wt% wetting agent was prepared as in Example 3. A swatch of 100% polyester woven fabric was dipped in the warm solution, padded to 60% pick-up, and dried at 195°F. The fabric was then cured at 335°F for 30 seconds.

The resulting fabric was initially stiff due to excess chemicals on the surface, but after 1 home wash the fabric became soft and drapable. There was no significant change in feel between 2 and 25 home washes. At 25 washes, the feel remains plump and thick compared to untreated polyester alone. Measure the wetting time of the sample:

Results: Wetting Time After Multiple Home Washes Wetting time processed unprocessed 0HL 8.2 seconds >120 seconds 1HL 3.2 seconds >120 seconds 5HL 8.3 seconds >120 seconds 10HL 13.3 seconds >120 seconds 25HL 18.3 seconds >120 seconds

Example 5: Protein Solution Application to Woven 100% Wool Fabric

A solution containing 10 wt% gelatin, 5 wt% DMDHEU and 0.1 wt% wetting agent was prepared as in Example 3. A swatch of 100% wool woven fabric was dipped in the warm solution, padded to 60% absorption, and dried at 195°F. The fabric was then cured at 335°F for 30 seconds.

The shrinkage of the wool sample in the warp and fill directions is measured and reported as a percent change relative to the sample before washing. Samples were measured after repeated home washing and tumble drying. Treated samples shrank less than untreated wool.

result: Shrinkage (warp/weft) processed unprocessed 1HL 3.2%/1.6% 7.6%/8.9% 5HL 3.3%/1.2% 8.8%/9.8% 10HL 4.0%/2.3% 12.5%/14.3%

Claims (17)

1. composite fibre matrix, it comprise core fibre and the protein crust that adheres to around described each core fibre and wherein the protein crust adhere by covalent bond and self.

2. the composite fibre matrix of claim 1, wherein the protein crust further comprises at least a helper component.

3. composite fibre matrix, it comprises core fibre and the protein crust that adheres to around described each core fibre and wherein prepare fibre substrate by following method:

Make the fibre substrate that contains core fibre and water soluble protein and crosslinking agent and not necessarily the aqueous solution of suitable crosslinking agent catalyst contact;

Not necessarily, fibre substrate is contacted with the acidic reduction agent, described reductant can make initial insoluble protein structure regeneration;

The heating fibre substrate is to dry; With

Solidify being enough to cause under the temperature of reacting between crosslinking agent and the protein.

4. the composite fibre matrix of claim 3, wherein aqueous solution further comprises at least a helper component.

5. the composite fibre matrix of claim 3, wherein this method further comprise make protein crust and the reaction of at least a helper component so that helper component is attached on the protein crust or within step.

6. claim 2,4 or 5 composite fibre matrix, wherein helper component is selected from colouring agent, metallic colloid, magnetic colloid, infrared absorbing compounds, uv-shielding compound, bioactivator, fire retarding chimical, antistatic additive, odor adsorption compound, neutralizer and hydrolyzable bridging agent.

7. any one composite fibre matrix of claim 1-6, wherein core fibre is synthetic fiber.

8. any one composite fibre matrix of claim 1-6, wherein core fibre is an artificial fibre.

9. any one composite fibre matrix of claim 1-6, wherein core fibre is a natural fabric.

10. method for preparing composite fibre matrix, this method comprises the steps:

Make the fibre substrate that contains core fibre and water soluble protein and crosslinking agent and not necessarily the aqueous solution of suitable crosslinking agent catalyst contact;

Not necessarily, fibre substrate is contacted with the acidic reduction agent, described reductant can make initial insoluble protein structure regeneration;

The heating fibre substrate is to dry; With

Solidify being enough to cause under the temperature of reacting between crosslinking agent and the protein; Obtain a kind of composite fibre matrix, it comprise protein crust that each fiber around described matrix adheres to and wherein the protein crust adhere by covalent bond and self.

11. the method for claim 10, wherein aqueous solution further comprises at least a helper component.

12. the method for claim 10, wherein further comprise make the reaction of protein crust and at least a helper component so that helper component is attached on the protein crust or within step.

13. the method for claim 11 or 12, wherein helper component is selected from colouring agent, metallic colloid, magnetic colloid, infrared absorbing compounds, uv-shielding compound, bioactivator, fire retarding chimical, antistatic additive, smell-absorption compound, neutralizer and hydrolyzable bridging agent.

14. any one method of claim 10-13 wherein further comprises the step of handling composite fibre matrix with the back processed agent that is usually used in wool.

15. any one method of claim 10-14, wherein core fibre is synthetic fiber.

16. any one method of claim 10-14, wherein core fibre is an artificial fibre.

17. any one method of claim 10-14, wherein core fibre is a natural fabric.