US20090206296A1

US20090206296A1 - Methods and compositions for improving the surface properties of fabrics, garments, textiles and other substrates

Info

Publication number: US20090206296A1
Application number: US12/371,569
Authority: US
Inventors: Bakul Dave
Original assignee: Southern Illinois University System
Current assignee: Southern Illinois University System
Priority date: 2008-02-14
Filing date: 2009-02-13
Publication date: 2009-08-20
Also published as: WO2009103024A2; WO2009103024A3

Abstract

The present invention discloses the use of organosilanes as a semi-permanent surface treatment for fabrics, textiles, and other materials. The present invention discloses a composition for this treatment comprising an organosilane, a catalyst, water, and a solvent. The present invention further discloses methods for improving water repellency and for providing other enhanced benefits to a substrate wherein the methods include contacting the substrate with a solution of water and a silane-based composition, removing excess solution from the substrate, and drying the substrate.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application Ser. No. 61/028,617, incorporated herein by reference, which was filed Feb. 14, 2008, to the extent allowed by law.

FIELD OF THE INVENTION

The invention relates to organosilane compositions, methods of making such compositions and methods for improving water repellency and other surface properties of fabrics, garments, textiles, and other materials using such compositions.

BACKGROUND OF THE INVENTION

Fabrics made from both natural and man-made fibers have an intrinsic tendency to absorb water due to the presence of hydrogen-bonding interactions on the surface. Textiles, fabrics, and garments are typically made of natural and synthetic fibers with functional groups that can participate in hydrogen bonding interactions. These interactions can be within the fibers of the garment or with exogenous molecules that come in contact with the fabrics during normal usage as well as during cleaning and normal fabric care processes. While all fibers typically have some hydrogen bonding groups, natural fibers made of cotton, wool, and other natural substances are characterized by a significant number of hydrogen bonding sites.
Fabrics and garments with hydrogen bonding sites react chemically and the nature and extent of these chemical reactions play a major role in the functional lifetime of such textiles. Similarly, interaction with humans during normal wear dictates a consumer's experience with these textiles. Consumers deem several factors critical to the useful lifetime of fabrics, garments, and textiles: a) breathability and feel of garments, 2) color retention, brightness, gloss and look of fabrics, 3) cleanliness of garments, 4) absence of bad odors, and 5) lack of fading and rupture of surface fibrils that deteriorate the fabric structure of garments.
Textiles, fabrics and garments made from natural and/or synthetic yarn and fibers are normally coated with a somewhat chemically inert coating (during their production and initial fabrication) that gives them the “new” look when they are brand new. However, prolonged usage as well normal fabric care processes associated with washing, cleaning, and laundering rapidly deplete the surface layer thereby exposing the native unprotected fibers. As a result, new fabrics gradually acquire the look of used fabrics after 2-3 cycles of wear and washing, or cleaning. Furthermore, these exposed fibers are more susceptible to chemical reactions with enzymes and other cleaning agents in the soaps and detergents. Over prolonged usage of such cleaning agents, fabrics and garments acquire the faded worn-out look due to surface pilling and irreversible adsorption of soiling and/or stain causing molecules.
The disruption of surface fibrils responsible for pilling of fabrics and loss of fiber mass in the form of lint also causes a fading of the colors and loss of surface smoothness in fabrics. This deterioration of surface fibrils causes light to scatter across the fabric surface and reduces the glossy finish desired by consumers. Therefore, prevention of pilling and loss of surface fibril structure is important to prolonging the useful life of fabrics and garments.
At a molecular level, the chemical interactions of fabrics are characterized by surface hydrogen bonding interactions that give rise to adhesion of water, staining agents, dirt and soil, bodily secretions, cellular components, microbes, and other exogenous entities that can bind to the fabric surface. In the same way, different chemical components in a detergent also bind to the surface of fabrics during the normal cleaning and laundry processes. The adhesion of these molecules to the surface of the fabric is facilitated by the hydrogen bonding sites on the textile fibers of the fabric.
A typical fabric cleaning process employs similar interactions for removal of soil and for cleaning of the fabrics. A fabric's ability to absorb water during the washing process is directly related to the surface hydrogen bonding sites. Subsequent drying times are dictated by the density of hydrogen bonding interactions. As such, polyester fabrics, for example, (which contain fewer hydrogen bonding sites) absorb less water during the washing process and also dry faster due to easy evaporation of water molecules. Therefore, the use of a coating to reduce the number of surface hydrogen bonding sites on fabrics or garments can minimize surface wetting and prevent adhesion of water, dirt, or other molecules to the surface of garments. This reduced binding of water means the fabrics are water resistant and easier to dry.
An additional factor in the wear and comfort of textiles relates to softness, fluffiness, and smoothness of fabrics. These attributes are related to mechanical properties of garments, specifically, to fibers that interact significantly with each other through hydrogen bonding interactions on the surface of a garment. Increased inter-fiber interactions mediated by hydrogen bonding interactions cause an increase in mechanical stiffness of fabrics. Strategies for imparting softness in fabrics normally employ reduction of inter-fiber interactions to make the fabrics soft and elastic.
Overall, the performance, wearability and useful life of fabrics and textiles is governed by chemical reactions mediated by hydrogen bonding sites on the fibers. The ability to control and regulate these reactions is key to enhancing the wearability and useful life of garments while, at the same time, minimizing the effort required for routine fabric care.
The principal reactants in chemical reactions on the surface of fabrics are the surface hydroxyl groups that bind to different chemical agents leading to adsorption of dirt and staining agents which make clothes dirty and soiled. The strength of these reactions dictates whether the stains are permanent or easily removable by dissolving them in detergent. Adsorption of different molecules on the surface of fabrics is also responsible for the development of odor in garments. Typically the odor causing molecules are gaseous molecules that can adsorb on the surface via hydrogen bonding interactions. An additional cause of malodor development in fabrics is the growth of mold, mildew, bacteria, and other microorganisms which attach to the fabrics and release metabolic products that give rise to odor causing molecules.
Organosilanes have been used in some treatments of fabrics and other substrates impart water repellency. However, one problem with such prior art compositions is that they are typically aerosols and not aqueous solutions. Also, typically such prior art compositions are not easily applied by the consumer and often require professional application of the water repellant composition. This aspect of the prior art compositions renders them relatively costly to apply and subject to one-time or infrequent application.
One of the problems frequently associated with organosilane based compositions is physical instability upon storage. This problem is usually accentuated when the composition is stored for significantly longer periods (e.g., greater than six months) at low temperatures (e.g., at 5 degrees C. or below) or at elevated temperatures (60 degrees C. or above). Physical instability can manifest itself as a thickening, gelling or solidification of organosilane. This thickening can occur to a level at which the liquid is no longer pourable, and can even lead to the formation of an irreversible gel. Such thickening is very undesirable because the composition can thereafter no longer be conveniently used for its intended purpose and/or it is unattractive to the consumer. For example, stable fabric conditioning concentrates are increasingly desired by the consumer. Generally, it would be desirable to have shelf-stabile organosilane based compositions.
Consumers may benefit from stable textile treatments that can be stored for extended periods under normal ambient temperature fluctuations, because such treatments can be applied to garments during normal usage and/or the fabric care process. It is preferable that these treatments: a) are simple products that consumers can use in their homes; b) are methods that consumers can apply during the normal laundry process; c) do not adversely affect the cleaning process and or detergent action required for laundering fabrics; d) are stable for extended durations without undergoing any phase change, change in structural consistency, or performance; and e) are effective in enhancing the desired characteristics of the fabric without leaving any visually perceptible residue on the surface that would negatively influence the visual appeal of the fabric. In many situations, it is desirable to dry fabrics following such treatment; however, the drying process may require a significant amount of energy depending upon the strength of the bond between the water and the fabric. Therefore, it would be more desirable to provide fabrics and other materials with water repellent properties that would reduce the energy required to dry them.
It would also be desirable to have treatment methods which provide 1) stain resistance, 2) water repellency, 3) softness, 4) brightness and optical gloss, 4) resistance to microbial adhesion and growth, and reduction of odors, 5) retention of visual appearance with respect to wear and tear associated with normal care, and 6) reduction of optical fading, chromatic shifts, surface deterioration, pilling, and lint formation in the surface to textiles, fabrics, garments and other substrates. It would be further desirable if such methods employ a shelf-stable organosilane based composition.

SUMMARY OF THE INVENTION

The present invention discloses the use of organosilane(s) as a semi-permanent surface treatment for substrates such as fabrics, garments, textiles, and other materials. These organosilanes adhere to the surface of the substrates via a combination of covalent and/or noncovalent interactions. A benefit of this treatment is that fabrics and other materials retain the native characteristics such as color, texture, breathability and overall feel while at the same time exhibiting enhanced optical properties, softness, smoothness, and overall ease of wearability. Some of the beneficial properties which result from this treatment are, without limitation: 1) stain resistance, 2) water repellency, 3) softness, 4) brightness and optical gloss, 4) resistance to microbial adhesion and growth, and reduction of odors, 5) retention of visual appearance with respect to wear and tear associated with normal care, and 6) reduction of optical fading, chromatic shifts, surface deterioration, pilling, and lint formation in the surface to which the treatment is applied.
The present invention further discloses a composition comprising: a) an effective amount of an organosilane or mixtures thereof, b) a catalyst, c) water, d) a solvent, and e) optionally, an emulsifier, thickener, or stabilizer for liquid conditioner applications. In an embodiment of the present invention, the organosilane composition is supplied in a liquid form that is suitable for use as a spray or as a liquid rinse conditioner, either of which is stable and maintains its liquid state without gelling under ambient conditions for extended periods of time.
The present invention also discloses a method for improving the water repellency and other properties including 1) stain resistance, 2) water repellency, 3) softness, 4) brightness and optical gloss, 4) resistance to microbial adhesion and growth, and reduction of odors, 5) retention of visual appearance with respect to wear and tear associated with normal care, and 6) reduction of optical fading, chromatic shifts, surface deterioration, pilling, and lint formation of fabrics and various materials comprising: a) treating the substrate with the composition, b) removing the excess solution from the substrate, and c) drying the composition under ambient conditions or alternatively, drying the composition at an elevated temperature in a dryer. Use of the composition in the present invention also may serve as a water and energy saving aid since the fabric, when treated with the organosilane composition, will absorb less water during the washing process and dry more quickly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a method for improving the water repellency of fabric according to one embodiment of the present invention;

FIGS. 2 a and 2 b illustrate the increased stain repellency after treatment of a fabric with a composition achieved according to the principles of the present invention;

FIG. 3 is a graph demonstrating the gradual weight change of shirts after washing and through the drying process for untreated fabrics and fabrics treated according to the principles of the present invention;

FIG. 4 is a graph illustrating the reduced bacterial growth for treated fabrics achieved according to the principles of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The invention is directed to methods and compositions for improving the surface properties of fabric and other materials and substrates. In some embodiments, the methods and compositions may improve stain resistance and other properties of fabric or other materials. In the examples which follow, the beneficial properties achieved may be imparted to fabrics and other materials, such as glass, plastics, ceramics, composites, metal, paper, wood, and leather, as well as other substrates. The terms “halides,” “alkoxides,” “carboxylates,” “phosphates,” “sulfates” “hydroxides,” “hydrides” and “oxides” are intended to have their art-recognized meanings. The terms “alkyl,” “alkenyl,” “alkynyl,” “phenyl,” “benzenyl hydrocarbon,” and “fluorocarbon” are also intended to have their art-recognized meanings.

Silane-Based Compositions

The treatment composition of the present invention comprises organosilane monomers, oliogomers, particles, polymers and/or gels of organosilicate materials made from a single component or mixtures of starting materials with the general formula (X)_nSi(R)_4-nand/or (X)_nSi—(R)_4-n—Si(X)_nwhere X is selected from the group consisting of halides, alkoxides, carboxylates, phosphates, sulfates, hydrides, hydroxides, and/or oxides and n=1, 2, or 3 and R is selected from the group consisting of alkyl, alkenyl, alkynyl, phenyl, or benzenyl hydrocarbon and/or fluorocarbon chain with 1-20 carbon atoms. The composition of the present invention further comprises water, at least one catalyst, at least one solvent to dissolve or disperse the components, and mixtures thereof. In an alternate embodiment the composition of the present invention may further comprise a stabilizer to improve the shelf-life; a thickener to achieve and maintain the desired viscosity, an emulsifier, a perfume, a dye, a preservative; or mixtures of any two or more such components. The composition of the present invention can also contain other ingredients to provide additional fabric care benefits, and/or to improve performance and formulation.
The composition of the present invention may be applied to fabrics or other materials as a liquid, a gel, or a particulate additive. The composition may be applied during the wash or rinse cycle of a routine laundry process.
Depending upon the application of the treatment composition, the amount (by % weight) of an organosilane or mixture of organosilanes in the composition can vary typically from about 0.1% to about 90%, preferably from about 1% to about 60%, and more preferably from about 3% to about 250%, by weight of the fabric treatment composition. The amount (by % weight) of water in the composition can vary from 0.001% to about 99%, preferably from about 1% to about 75%, and more preferably from about 2% to about 20%, by weight of the fabric treatment composition. The amount (by % weight) of a catalyst in the composition can vary from 0.001% to about 20%, preferably from about 0.1% to about 10%, more preferably from about 2% to about 5%, by weight of the fabric treatment composition. The amount (by % weight) of a stabilizer in the composition can vary from 0.1% to about 10%, preferably from about 0.1% to about 1%, and more preferably from about 0.2% to about 0.5%, by weight of the fabric treatment composition. The amount (by % weight) of thickener in the composition can vary from 0.1% to about 10%, preferably from about 0.1% to about 1%, more preferably from about 0.2% to about 0.5%, by weight of the fabric treatment composition. The amount (by % weight) of the solvent in the composition can vary from 1% to about 99.999%, preferably from about 10% to about 90%, and more preferably from about 50% to about 80%, by weight of the fabric treatment composition. The amount (by % weight) of the fragrance can vary from 0% to about 15%, preferably from about 0.1% to about 6%, and more preferably from about 0.2% to about 5%, by weight of the fabric treatment composition.
The compositions of the invention have a pH of at least about 1.5, and less than about 5, preferably the pH is from about 2.5 to about 6, and more preferably from about 4 to about 7.5.
Examples of useful catalysts for the composition of the invention include without limitation: a) inorganic acids HCl, HNO₃, H₂SO₄, H₃PO₄, and b) organic acids: RCOOH where R is alkyl, alkenyl, alkynyl, phenyl, or benzenyl hydrocarbon chain with 1-20 carbon atoms; or c) dicarboxylic acids, HOOC—(CH₂)n-COOH with n=1-10. Specific carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, lactic acid, maleic acid, malic acid, fumaric acid, tartaric acid, citric acid, isocitric acid, aconitic acid, and amino acids may be used. Polycarboxylic acids such as polyacrylic acids may also be used. Protonated amines N(H/R)-3-n[HX] where X=halides, nitrates, phosphates, sulfates, and n=0, 1, or 2 and R is alkyl, alkenyl, alkynyl, phenyl, or benzenyl hydrocarbon chain may also be selected. Quaternary ammonium silanes such as Octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, (2-N benzylaminoethyl)-3-aminopropyl trimethoxysilane, hydrochloride; n,n-Didecyl-n-methyl-n-(3-trimethoxysilylpropyl)ammonium chloride; and Tetradecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, N-(trimethoxysilylethyl)benzyltrimethylammonium chloride may also be selected.
Examples of useful solvents include alcohols, ketones, and esters and similar compounds. Specifically, more preferred solvents include ethanol, propanol, isopropanol, butanol, t-butanol and similar compounds. Additionally, the following solvents may be used: polyols such as, for example, ethylene glycol, propylene glycol, glycerol, and esters such as, for example, benzyl acetate, ethyl acetate, and lactic acetate.
Examples of thickeners and emulsifiers include, pectin, maltodextrose, carbomer (carbopol) polymers, propylene glycol, ethylene glycol, polyethylene glycol, glycerol, polypropylene glycol, polyethylene oxide, polypropylene oxide, copolymers of PEO-PPO, copolymer PEG-PPG, PEG-functionalized silicone polymers (viscosity 10-600 cSt), PEO-functionalized silicone polymers (viscosity 10-600 cSt); PPO-functionalized silicone polymers (viscosity 10-600 cSt) Polysaccharides, starches, agar, carrageenan, and gums and similar compounds. Emulsifiers such as sorbitol, and triton x-100 may also be used.
As is known in the art, in addition to the above compounds, examples of stabilizers may also include; hydrogen chloride (HCl) and sodium hydroxide (NaOH).
Examples of fragrances may include aldehydes, alcohols, ketones or esters of the types generally used in perfumes; amyl benzoate, benzophenone, benzyl salicylate, cyclohexyl salicylate, carvacrol, citral, citronellol, anisole, benzaldehyde, benzyl acetate, benzyl acetone, benzyl alcohol, benzyl formate, benzyl iso valerate, benzyl propionate, dimethyl benzyl carbinol, ethyl benzoate, ethyl cinnamate, ethyl hexyl ketone, fructone, frutene (tricyclo decenyl propionate), cyclohexyl ethyl alcohol, geraniol, alpha-ionone, isobornyl acetate, isobutyl benzoate, and isononyl alcohol and similar compounds.
The treatment conditioner product of the present invention may be in the form of a liquid, gel, paste, spray, or foam, for example. Examples of the commercial product include a spray, a soaking product, a rinse additive conditioner, a finishing agent, or a main wash product integrated with a suitable liquid detergent formulation. The composition of the present invention may be applied to a fabric, garment or other substance via dipping, soaking, misting, or via a spraying process, followed by a drying step. Compositions of the present invention may include, for example: a) spray compositions for independent in-home or commercial treatments, and b) fabric conditioning compositions for use in the rinse cycle of a laundry process, in particular the rinse cycle of a domestic or industrial laundry process. The compositions of the present invention are preferably present as a clear liquid for use as a spray, or as a viscous liquid for use as a rinse additive conditioner, either of which is stable and maintains its liquid state without gelling under ambients conditions for extended periods of time. See Tables, 1, 1a, and 1b below. The compositions according to the present invention preferably have a viscosity in the range of about 0.3 cP to about 5 cP for spray compositions and about 100 cP to about 450 cP in the form of liquid conditioner formulations. It is a particular advantage of the present invention that viscosities in this range can be achieved without the use of expensive additional viscosity control agents in the formulations, as is known in the art.
Without wishing to be bound by theory, it is believed that the organosilane(s) improve fabric properties by binding to the fibers in the fabric. It is believed that the organosilane molecules interact with the hydrogen bonding sites of the fibers via the silanol terminals of the hydrolyzed silanes. It is believed that when the organic groups on the silanol species bond to the fibers, their environment thereby alters a majority of the fabric surface such that the majority of the surface is comprised of hydro(fluoro)carbon chains. It is believed that this reduction in surface hydrogen binding sites is responsible for the functional enhancement of the garments observed in the present invention.
Without wishing to be bound by theory, it is believed that, within the compositions of the invention, the organosilane species are stabilized in the liquid state without undergoing chemical reactions to form gels and/or solids. Typically, the liquid compositions of the present invention can be stable for extended periods without exhibiting any change in physical state, consistency, viscosity or functional performance. It is believed that the formation of gels and solids by the organosilane compounds of the present invention is prevented by the hydrogen bonding, cationic or anionic additives in the composition which provide the dual functions of: a) acting as dispersion aids, and b) acting as silanol condensation inhibitors.
In the field of the art, the term “silica-based compositions” is commonly used to refer to the hydrolyzed silanes which are present in the compositions of the present invention.

TABLE 1

General Compositions

Component	General Type	Weight %

Spray Formulation

Organosilane	Terminal R group (X)_nSi(R)_4-n	0.1 to 20
	And/or bridging R Group	(Preferably 0.2-10
	(X)_nSi—(R)_4-n—Si(X)_nOr	More preferably 0.5-5)
	mixtures
Acid Catalyst	Inorganic or Organic	0.001% to 5%
Water		0.001% to 5%
Solvent	Alcohol (ethanol,	balance
	isopropoanol, Butanol, sec-
	butanol, t-butanol). Ketones.
Fragrance	Various	0.1 to 2%
(optional)

Conditioner Formulation

Organosilane	Terminal R group (X)_nSi(R)_4-n	1 to 60
	And/or bridging R Group	(More preferably 5-25)
	(X)_nSi—(R)_3-n—Si(X)_nOr
	mixtures
Acid Catalyst	Inorganic or Organic	0.001% to 5%
Water		1% to 75%
		(more preferably 5-25)
H-bonding,	Various embodiments	0.1% to 10%
cationic or
anionic
species.
(thickener,
emulsifier,
stabilizer)
Solvent	Alcohol, ketone or ester	balance
Fragrance	various embodiments	0.1 to 2%
(optional)

TABLE 1a

Examples of Spray Compositions with Stability Data

Chemical	Weight Percent	Stability

Composition I

HexylTrimethoxy Silane	5	Visual observance of
0.04 M HCl	0.001	stability for at least
Isopropanol	Balance	3 years

Composition II

OctylTrimethoxy Silane	5	Visual observance of
0.04 M HCl	0.001	stability for at least
Isopropanol	Balance	2.5 years

Composition III

HexadecylTrimethoxy Silane	5	Visual observance of
0.04 M HCl	0.001	stability for at least
Isopropanol	Balance	2.5 years

Composition IV

OctadecylTrimethoxy Silane	5	Visual observance of
0.04 M HCl	0.001	stability for at least
Isopropanol	Balance	3 years

Composition V

1,6-Bis(trimethoxysilyl)-	5	Visual observance of
Hexane		stability for at least
0.04 M HCl	0.001	3 years
Isopropanol	Balance

Composition V

1,8-Bis(trimethoxysilyl)-	5	Visual observance of
Octane		stability for at least
0.04 M HCl	0.001	3 years
Isopropanol	Balance

TABLE 1b

Examples of Rinse Compositions and Stability Data

Chemical	Weight Percent	Stability

Composition I

HexylTrimethoxy Silane	25	Visual observance of
0.04 M HCl	0.1	stability for at least
Polyethylene oxide	1%	2 years
Isopropanol	Balance

Composition II

HexadecylTrimethoxy Silane	25	Visual observance of
0.04 M HCl	0.1	stability for at least
Polyethylene oxide	1%	1 year
Isopropanol	95

Composition Tested III

OctadecylTrimethoxy Silane	25	Visual observance of
0.04 M HCl	0.1	stability for at least
Carbomer 910	1%	2 years
Ethanol	95

Composition Tested IV

HexylTrimethoxy Silane	25	Visual observance of
0.04 M HCl	0.1	stability for at least
Polyethylene oxide	1%	2 years
Isopropanol	94

Composition Tested V

HexylTrimethoxy Silane	15	Visual observance of
citric acid	5	stability for at least
Octadecyldimethyl(3-	5%	1.2 years
trimethoxysilypropyl)
ammonium chloride
Water	24
Ethanol	Balance

Composition Tested VI

HexadecylTrimethoxy Silane	25	Visual observance of
Malic acid	5	stability for at least
N-Trimethoxysilypropyl, N,	5%	1 year
N,N-trimethyl ammonium
chlorde
Water	24
Isopropanol	Balance

Composition Tested VII

HexylTrimethoxy Silane	15	Visual observance of
0.04 M HCl	0.1	stability for at least
Dimethylsiloxane-Ethylene	10%	1 year
oxide Copolymer &5% non-
siloxane (Gelest DBE712)
Water	25
Isopropanol	Balance

Formulations of the type illustrated in the previous tables above may be mixed with any alkoxysilane with a terminal or bridging R group. The compounds with chains longer than 6 carbon atoms generally may exhibit greater shelf stability than compounds with fewer than 6 carbon atoms in embodiments of the invention which include premixed consumer products.

Methods of Improving Water Repellency and Other Properties of Fabrics and Various Materials

An embodiment of the present invention also discloses a method for improving the water repellency of fabrics and other materials comprising: a) blending the organosilane compound, a catalyst, a solvent, and water to form a silane-based composition, b) treating the substrate with the composition, c) removing the excess solution from the substrate, and d) drying the composition under ambient conditions or alternatively, curing the composition at an elevated temperature in a dryer. FIG. 1 illustrates a method 100 for improving water repellency of a fabric 110 according to one embodiment. This method 100 comprises contacting the fabric 110 with an aqueous solution 120 or treatment solution that comprises water and a silane-based composition. In this embodiment, the solution is used primarily to improve water repellent properties of the fabric 110 through the creation or deposition of a coating on the fabric 110. Additionally, the solution 120 can also serve auxiliary functions such as cleaning and conditioning the fabric. The fabric 110 can also be contacted with a plurality of other solutions, concurrently or separately with the treatment solution providing the water repellent properties and, concurrently or separately from each other, each solution serving a different purpose. For example, the fabric 110 could be contacted with one or more solutions to clean or remove stains from the fabric 110, condition the fabric 110, or treat the fabric 110 to improve stain resistance.
In an embodiment, the fabric 110 is contacted with the aqueous solution 120 either by adding the fabric 110 to the aqueous solution 120 or adding the aqueous solution 120 to the fabric 110. The fabric 110 and aqueous solution 120 mixture can be agitated or stirred to ensure even contact between the fabric and the active ingredients in the silane-based composition in the aqueous solution 120.
In an embodiment, ingredients of the silane-based composition are combined with the fabric 110 and agitated at room temperature for approximately 10 minutes. The optimal temperature and time duration may vary according to: a) the type of washer being used (e.g., top loading, front loading, high efficiency); b) the capacity of each automatic washer; c) the fabric load in each automatic washer (e.g., full, medium, half, quarter, small etc.); d) duration of the wash cycle (e.g., normal, heavy); the duration of the rinse cycle (e.g., short, medium, long); e) the water temperature settings of each automatic washer (e.g., cold, warm, or hot); and f) other variable settings of each automatic washer.
The amount of time in which the fabric 110 is in contact with the aqueous solution 120 depends partly on the material of fabric 110 being treated (e.g., cotton, polyester, rayon), the type of fabric 110 (e.g., knitted, woven), the relative ratios of the silane-based mixture to water, and the amount of fabric 110 being treated. For example, use of higher concentrations of the silane-based mixture may require less contact time to impart desired properties to the fabric 110. Similarly, longer contact times may be required to treat large amounts of fabric 110.
Referring again to FIG. 1 after contacting the fabric 110 with the aqueous solution 120, any excess aqueous solution 120 is then removed from the fabric 110. The aqueous solution 120 can be removed from the fabric 110 by either draining the aqueous solution 120 from the fabric 110, applying manual pressure to the fabric 110 (e.g., twisting or squeezing), or applying centrifugal forces to the fabric 110 (e.g., spinning in a washing machine). In some embodiments, removal of the excess aqueous solution 120 from the fabric 110 occurs in either the rinse or the spin cycle of an automatic washing machine. Alternatively, the fabric 110 can be rinsed with water to remove excess aqueous solution 120 and any other residual cleaning and treatment agents.
After contacting fabric 110 with the aqueous solution 120 and removing the excess aqueous solution 120 from the fabric 110, the fabric 110 is dried in step 130. In some embodiments, the drying 130 occurs in an automatic laundering and drying system. The automatic tumble dryer may be configured to apply heat to the fabric 110. In an embodiment, the automatic tumble dryer is configured to operate at a drying temperature of approximately 135° F. The drying temperature will vary depending on the types of fabrics 110 being used and whether the fabrics 110 have been treated with any chemicals. In other embodiments, the drying 130 occurs in the same machine as the other operations of method 100. In yet other embodiments, the drying 130 occurs without the aid of heat (e.g., air drying in dryer, line drying at room temperature, or line drying with assistance of external fan).
The automatic laundering and drying system may include one or more washing machines and at least one dryer. The washing machines may each contain a set of cycles associated with the washing process such as wash, rinse, and spin. Alternatively, each washing machine may be configured to perform a specific function associated with each cycle. For example, the fabric 110 may be contacted with the aqueous solution 120 during the wash or the rinse cycle. This coats the fabric 110 with the active ingredients in the silane-based composition that, as previously mentioned, reduces the absorption of water by the fabrics and hence increases water repellency of the fabric.
The method of the present invention may be carried out as a treatment of the fabric before or after it has been made into garments, for example, as part of an industrial textile treatment process. It may be provided as a spray composition, e.g., for domestic (or industrial) application to fabric in a treatment separate from a conventional domestic laundering process. Alternatively, in the method of the present invention, the treatment is carried out as part of a laundering process. Suitable laundering processes include large-scale and small-scale (e.g., domestic) processes, in which the fabric care composition of the invention may be used in the rinse cycle or sprayed onto a fabric. It is particularly advantageous, and surprising, that the composition can be cured simply by drying, even under room temperature conditions. Alternatively, a tumble dryer can be used to accelerate the curing process. See Table 2 below.
A further advantage of the method of the present invention is that, when the composition is applied as a spray, one application is sufficient to obtain the desired benefits for many subsequent washes. If the composition of the present invention is applied during the wash or rinse cycle of a laundry process, a progressive build-up of benefits is observed after each wash, although curing with a tumble dryer is required after each wash. Thus, garments become progressively more stain and water repellent, progressively softer and smoother, and appear brighter with each successive application. Similar effects were observed for application of the composition as a rinse conditioner.
A comparison test on treated and untreated garments illustrates the increased stain repellency in fabrics treated with the composition of the present invention. Each garment is exposed to a small amount of the staining agent for a given amount of time. In one experiment, the spray treated fabric was exposed to tea for 5 minutes, 10 minutes, 20 minutes, and 30 minutes. Another sample of the spray treated fabric was then exposed to coffee for the same time intervals-5 minutes, 10 minutes, 20 minutes, and 30 minutes. For both tea and coffee, the treated fabric does not show any residual stain, even after 20 minutes. In contrast, the untreated fabric has some residual stain left after a short exposure time. These results are depicted in FIGS. 2 a and 2 b.
In one embodiment, the components of the silane-based composition are premixed before use. The maximum amount of time between the preparation of the composition and the actual use of the composition (without sacrificing performance of the treatment) will vary depending on the interactions of the stabilizer with other components of the composition, the physical state of the composition (e.g., liquid, gel or particulate suspension), and the pH of the composition. Alternatively, a portion of the components may be prepared in advance while other components are combined later. In yet another embodiment, all of the components may be concurrently combined with a fabric at the time of treatment. In yet another embodiment, a fabric may be contacted with a solution of the present invention multiple times or with fresh solutions. For example, the fabric is contacted with the composition once, and then as needed, contacted with the composition subsequent times if necessary.
The silane-based composition of the present invention reduces the amount of energy consumed and the time required for drying the fabric by reducing the number of hydrogen bonding sites on the fabric surfaces. The reduction of hydrogen bonding sites on the fabric enhances the water repellency of the fabric because the fabric absorbs less water. Fabrics treated with the composition absorb approximately 20% to approximately 25% less water compared to untreated fabrics at the end of washing. See Tables 2, 3, 4 and FIG. 3. Additionally, the treated fabrics show approximately 10% to approximately 25% reduction in drying time when drying the fabric in a tumble dryer. In FIG. 3, AATCC stands for the American Association of Textile Chemists and Colorists. AATCC detergent is a standard detergent used for testing since commercial detergents vary significantly in their formulation from brand to brand, the AATCC detergent provides a universal standard. The graph plots weight change of twelve polo shirts as they dry. The equilibrium dry weight is the weight of the polo shirts left at Room temperature before washing. The t=0 weight of the load treated with Sol-Gel starts out the lowest because it retains less water. Also, this load achieves the equilibrium dry weight much faster as compared to untreated shirts. Depending upon the load type the reduction in drying time ranges typically from 15 to 20%. The formulation used was Composition VII from Table 1b.
In one embodiment, a solution formulated according to the principle of the present invention includes approximately 90-100 g of the silane-based mixture discussed above per approximately 15 gallons of water. This ratio may change depending on; a) the type of fabric being treated, b) amount of fabric being treated, c) the type of each of the automatic washers being used (e.g., top loading, front loading, high efficiency), d) the capacity of each of the automatic washer being used, the fabric load in each of the automatic washers (e.g. full, medium, half, quarter, small), e) the setting of the water temperature used in each of the automatic washers (e.g., cold, warm, hot), and f) other variable settings of each automatic washer being used.
In the present invention, the treated fabric may be cotton, polyester, rayon, silk acetate, nylon, wool, or combinations thereof. The composition of the solution of the present invention and other parameters of method 100 (e.g., contact time and drying time) may vary depending on the type of fabric being treated, as different fabrics may have different numbers of hydrogen bonding sites.
In some embodiments, a coating on a fabric or other material can be removed or dissolved by contacting the fabric or other material with a basic compound (e.g., pH>7.0). The basic compound may include sodium hydroxide, potassium hydroxide, detergent, or any combinations thereof. The basic compound to be contacted with the fabric may be present in the form of a solution, a gel, or other physical state. The coating may be removed either completely or partially while washing the fabric with detergent in the wash cycle of an automatic washer. Alternatively, the coating could be removed from the fabric under other circumstances (e.g., while the fabric is being conditioned, while the fabric is being rinsed, while the fabric is being spun dry, or before the fabric is washed).

TABLE 2

Water Spray AATCC #22

Tide-dried at	Tide-dried at
155 F. for 30 min.	135 F. for 10 min.	Tide-ambient cure

1W

	50	1W	50	1W	0
2W	60	2W	70	2W	60
2K	60	2K	60	2K	50
PW	75	PW	75	PW	70
PK	75	PK	70	PK	75

No Tide-dried at	No Tide-dried at
155 for 30 min.	135 F. for 10 min.	No Tide-ambient cure

1W	55	1W	55	1W	55
2W	60	2W	65	2W	70
2K	60	2K	60	2K	70
PW	75	PW	75	PW	70
PK	70	PK	70	PK	70

W = woven fabric swatch, K = knitted fabric swatch, P = poly-cotton blend

The rating numbers provided in Table 2 above for each sample are based on % of the fabric NOT wetted by water. A higher number indicates greater water resistance in the fabric. Untreated samples will be wetted completely and the rating number would approach zero. The curing process for the fabrics occurs regardless of temperature.

TABLE 3

Residual Moisture Content (1 polo shirt)

			% RMC change
	Wt(Wash	Wt (wash	[(water-
	with	with rinse	solgel)/original) ×
Dry Weight	Water)	additive)	100

(Sample A) 285.77 g	588.8	538.5 g	17.60%
(Sample B) 285.8 g	589.2	535.9 g	18.60%

TABLE 4

Drying rate of 12 polo shirts
Water Drop Test AATCC 193

Treatment	1W	2W	2K	PW	PK

Rinse: Dried in dryer at 155 F.	2	4	3	3	4
for 30 min
Rinse: Dried in dryer at 155 F.	2.5	4	3	3	4
for 10 min
Rinse: Ambient Hang Dried	2.5	3.5	3	2	4
Spray: Ambient Hang dried.	4	4	4	4	4

W = woven fabric swatch, K = knitted fabric swatch, P = poly-cotton blend

Table 4 above illustrates the weight of load as a function of drying time in a tumble dryer. The ratings numbers indicate the relative water repellency of different conditions. In general, the spray treated samples have a higher water repellency than the rinse treated samples.

TABLE 5

Lint reduction for a load of 12 garments

	Treatment	Weight (g)

	Dry weight	3326.7
	Lint trapped in lintguard when washed with	0.286
	tide
	Lint trapped in lintguard when washed with	0.071
	tide and rinsed with sol-gel

Treatment of fabrics and other materials with the compositions and methods of the present invention also results in improved softness of the fabric, improved brightness and optical gloss, improved resistance to bacterial growth and reduced surface deterioration and lint formation. See FIG. 4 and Table 5. In FIG. 4, microbial growth in the fabrics was measured over time. Treated and untreated fabrics swatches were exposed to the environment for one week followed by monitoring bacterial growth in culture medium under ambient conditions. The absorbance value directly relates to bacterial concentration.
A major consideration for comfort associated with a garment is the breathability of the textiles and garments. Breathability of fabrics, textiles and garments is an important attribute that is highly desired by wearers. Coating garments typically retards the flow of gaseous molecules such as oxygen and water vapor across the air-garment-skin interface. Ease of garment wearability and breathability (among other attributes) depends upon the diffusion, flow and permeation of oxygen and air across the air-garment interface and counter-flow of water vapor, surface reaction byproducts, and other metabolically generated gaseous molecules across the garment-skin interface into the environment. The breathability of fabric is illustrated in Table 6 below.
In typical usage scenarios, the bi-directional diffusion and permeation of gaseous molecules is governed by the physical and chemical characteristics of the garment acting as a membrane barrier. Under such a theoretical model, the diffusion of gaseous molecules and permeability of the garment membranes is dictated by the porosity of the textile weave and the degree to which it enables the flow of molecules thru the open spaces in the membrane.
Without wishing to be bound by theory, it is believed that the enhanced transport of vapors across the garment membranes is due to modification of the surface chemical structure. It is further believed that the treatment of fabrics by the formulation alters both the physical as well as chemical characteristics of woven/knitted garments comprised of an inter woven network of fibers and channels. It is believed that the fibers and channels of treated garments are modified so as to enhance and facilitate diffusion, permeability and transport of gaseous entities through the fabrics. It is believed that the treatment alters the chemical structure of channel surfaces thereby reducing the extent or hydrogen bonding interactions with the water molecules, which results in chemically unencumbered flow of vapors and faster transport rates. Furthermore, it is believed that the treatment acts as binder for the fibrils present in the garment. As a result, the individual fibers comprising the network in the garment exhibit relative compactions thereby making the porous structure more well-defined, streamlined, and favorable for passage of molecules. This smoothing of channels in the garments results in physically unencumbered flow of vapors and faster transport rates.
Without wishing to be bound by theory, it is further believed that the transport of gaseous molecules through treated garments is actively facilitated by the treated fabric such that the chemical functionalities present in the treatment contribute to enhancing the transport rates through the garments. It is believed that the reduction of hydrogen bonding sites on the fibers as wells as the streamlining of channels acts in concert to accelerate the rate of vapor transport across the fabrics. It is believed that reduced hydrogen bonding interactions lower the surface energy of vapor droplets while the streamlined lined channels reduce the activation energy associated with physical migration of the vapors through the channels. It is believed that the physical migration of water vapors and the reduced activation energy is favored by the increased lubrication and softness of fibers in the fabrics. It is believed that the synergistic cooperation of these effects contributes to enhanced vapor transport across the fabric channels. See Table 6.

TABLE 6

Breathability of Fabric

	Weight	% Water Vapor Lost

Uncoated Sample
After 15 hours at Ambient	96.84 g	3.16%
Temperature
After 5 hours at 55 C.	92.247 g	7.753%
After 26 hours at 55 C.	67.77 g	32.23
Coated Sample
After 15 hours at Ambient	95.96 g	4.04%
Temperature
After 5 hours at 55 C.	90.084 g	9.916%
After 26 hours at 55 C.	59.05 g	40.95

Table 6 above illustrates the breathability of fabric. Two identical beakers containing an identical amount of water (100 g) were fitted with 100% cotton swatches (one treated with the organosilane compound of the present invention and another untreated) and secured with a rubber band to cover the mouth of the breakers. The weight of the water remaining in the beaker was measured to determine the amount of water vapor lost through the fabric swatches acting as permeable membrane. The original amount of water is 100 g.
Use of the compositions of the present invention also may serve as a water and energy saving aid since the fabric, when treated with the organosilane composition, will absorb less water during the washing process and dry more quickly.
For example, the methods of the present invention results in a 15% reduction in drying time and therefore, yields 15% savings in time, energy and cost to the consumer. Typical energy consumption of a dryer is about 2500 W/hr. A 15% reduction for treated garments would correspond to 2125 W/hr (i.e. a savings of 375 W/hr). Typical households do about 350 loads of laundry per year and that would correspond to energy savings of about 130 kW/hr per year. In terms of cost, typical dryer energy consumption cost is estimated to be about 45 cents per load. A saving of 15% corresponds to saving of 7 cents per load. At 350 loads per year, total savings amounts to about $25 per year.
By their very nature organosilicates are characterized by luminescence in UV region. This property of organosilicates imparts brightness to fabrics treated with the organosilicate formulation.
Fabrics treated with compositions of the present invention have been observed to appear brighter as compared to untreated fabrics or fabrics treated with other commercial conditioners available in the market. These differences in fabric properties were visually observed. A treatment with the composition of the present invention also makes whites appear whiter, and dark colors appear more saturated and darker.
Softness or fluffiness of fabrics is related to interactions between fibers in the fabrics. These interactions determine the mechanical properties such as elasticity, tensile strength and stiffness. The inter-fiber interactions are due to hydrogen binding interactions which hold the fibers together. A disruption of hydrogen bonding interactions upon treatment with the organosilicate based fabric conditioner formulation of the present invention causes the fibers to interact less with each other, thereby making the fabrics softer.
Fabrics treated with compositions of the present invention have been observed to exhibit softness as compared to untreated fabrics or fabrics treated with other commercial conditioners available in the market. These differences in fabric properties were observed by tactile feel of the fabrics. A treatment with formulations of the present invention makes fabrics smoother and more silk-like in their tactile feel.
New fabrics are typically coated with a coating; however, prolonged usage and normal fabric care depletes that coating and also makes the surface look “fuzzy”, worn out, and faded due to the unraveling of fibrils in the fabrics. The organosilicate formulations of the present invention act as a glue or binder and seals the surface fibrils to make the surface appear new. Fabrics look newer, whites appear whiter and dark colors appear more saturated, all giving the surface a smooth feel or silk-like texture.
Fabrics treated with formulations of the present invention have exhibited increased surface smoothness as compared to untreated fabrics or fabrics treated with other commercial conditioners available in the market. These differences in fabric properties were observed by tactile feel of the fabrics while visual attributes were visually observed. A treatment with compositions of the present invention makes fabrics look newer and more visually appealing.
Development of odors in fabrics is related to a) adsorption of gases from the environment, b) degradation of chemical products secreted from the body, and c) production and degradation of bacterial growth. The fabrics treated with the organosilicate formulation of the present invention prevent adhesion and deposition of molecules due to the removal of hydrogen bonding interactions on the surface of the fabric. Similarly, the treated surface prevents adsorption, adhesion and binding of bacterial and microbial entities such as mold and mildew on garment surfaces. As a result, the garments treated with the organosilicate formulation show a significant retardation in odor development.
Fabrics treated with formulations of the present invention have been observed to have substantially decreased odor development as compared to untreated fabrics or fabrics treated with other commercial conditioners available in the market. These differences in fabric properties were observed in a six month study on different garments, and the odor developed on the fabrics was monitored during their continuous use. During the study, the treated fabrics did not develop any perceptible odor even after several weeks of continuous use as compared to untreated fabrics that developed odor after one or two days of continuous use. Additionally, a treatment with formulations of the present invention makes fabrics resistant to development of mold and mildew in other damp fabrics such as towels.
The foregoing description has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications in order that others skilled in the art may best utilize the invention and its embodiments, with various modifications suited to the particular use contemplated.

Claims

1. A silane-based composition, the composition comprising:

an organosilane;

an acid catalyst;

a solvent; and

water.

2. The composition of claim 2, wherein the organosilane has a general formula selected from the group consisting of (X)_nSi(R)_4-nand (X)_nSi—(R)_4-nSi(X)_nand combinations thereof;

wherein X is selected from the group consisting of halides, alkoxides, carboxylates, phosphates, sulfates, hydroxides, hydrides, oxides, and combinations thereof; and

wherein R is selected from the group consisting of an alkyl, alkenyl, alkynyl, phenyl, benzenyl hydrocarbon, and fluorocarbon chain with 1-20 carbon atoms, and combinations thereof.

3. The composition of claim 1 further comprising at least one compound selected from the group consisting of a thickener, an emulsifier and a stabilizer.

4. The composition of claim 3, wherein the thickener is selected from the group consisting of polyethylene glycol, polypropylene oxide, polyvinyl alcohol, and combinations thereof.

5. The composition of claim 1, wherein the solvent is selected from the group consisting of acetone, ethanol, propanol, isopropanol, butanol, ethyl lactate, ethylene glycol, propylene glycol, glycerol, and combinations thereof.

6. The composition of claim 1 wherein the organosilane is present in an amount of about 0.1% by weight to about 90% by weight.

7. The composition of claim 1 wherein the water is present in an amount of about 1% by weight to about 75% by weight.

8. The composition of claim 1 wherein the catalyst is present in an amount of about 0.1% by weight to about 10% by weight.

9. The composition of claim 3 wherein the stabilizer is present in an amount of about 0.1% by weight to about 1% by weight.

10. The composition of claim 3 wherein the thickener is present in an amount of about 0.1% by weight to about 1% by weight.

11. The composition of claim 1 wherein the solvent is present in an amount of about 10% by weight to about 90% by weight.

12. The composition of claim 1 wherein the composition is a product used for care and treatment of fabric.

13. The composition of claim 1 wherein the composition has a pH in the range of about 2.5 to about 7.5.

14. A method for applying a treatment to a substrate comprising:

contacting the substrate with a solution of water and the composition of claim 1;

removing, from the substrate, the excess solution; and

drying the substrate;

wherein the treatment produces a beneficial property.

15. The method of claim 14 wherein the beneficial property is stain resistance.

16. The method of claim 14 wherein the beneficial property is water repellency.

17. The method of claim 14 wherein the beneficial property is softness.

18. The method of claim 14 wherein the beneficial property is brightness and optical gloss.

19. The method of claim 14 wherein the beneficial property is resistance to microbial adhesion and growth, and reduction of odors.

20. The method of claim 14 wherein the beneficial property is retention of visual appearance with respect to wear and tear associated with normal care.

21. The method of claim 14 wherein the beneficial property is a reduction in optical fading and chromatic shifts.

22. The method of claim 14 wherein the beneficial property is a reduction in surface deterioration, pilling, and lint formation.

23. The method of claim 14 further comprising blending at least one organosilane, an acid catalyst, a solvent, and water with at least one compound selected from the group consisting of a thickener, an emulsifier and a stabilizer to form a silane-based composition.

24. The method of claim 14 wherein the silane-based composition is in the form of a spray.

25. The method of claim 15 wherein the silane-based composition is in the form of a liquid conditioner.

26. The method of claim 14, wherein the substrate is a fabric and the contacting and the removing occurs in an automatic washing machine.

27. The method of claim 14, wherein the substrate is a fabric and the removing of excess solution from the fabric occurs during a spin cycle of the automatic washing machine.

28. The method of claim 14, wherein the substrate is a fabric and the drying occurs in an automatic tumble dryer.

29. The method of claim 14, wherein the substrate is a fabric and the drying includes applying heat to the fabric.

30. The method of claim 14, wherein the substrate is a fabric and further wherein the fabric is selected from the group consisting of cotton, polyester, rayon, nylon, acetate, silk, wool, and combinations thereof.

31. The method of claim 14 wherein the substrate is a fabric and further wherein the method is carried out as part of an industrial textile treatment process prior to manufacturing a fabric into garments.

32. The method of claim 14 wherein the substrate is a fabric and further wherein the method is carried out as part of a domestic, commercial, or industrial laundering process for garments.

33. The method of claim 14 wherein the drying occurs under ambient conditions.

34. A method for increasing the shelf stability of an organosilane composition comprising:

blending at least one organosilane, an acid catalyst, a solvent, and water to form a silane-based composition; and

monitoring the stability of the composition under ambient conditions.

35. The method of claim 34 further comprising blending at least one organosilane, an acid catalyst, a solvent, and water with at least one compound selected from the group consisting of a thickener, an emulsifier and a stabilizer to form a silane-based composition.