Silicone Gel for Ease of Ironing and Better Looking Garments After Ironing

This invention relates to fabric care compositions and to a method for treating fabrics in order to improve various properties of the fabric, in particular, ease of ironing and improved appearance after ironing.

In the modern world the vast majority of clothing is made from woven fabrics, and the art of weaving is many centuries old. Indeed the invention of weaving is generally attributed to the Ancient Egyptians. Yarns were produced from natural cotton, wool, or linen fibers, and garments made from fabrics woven from these yarns often creased badly in wear and, when washed, required considerable time and effort with a smoothing iron to restore them to a pristine appearance.

Within the last half century, textile manufacturers have implemented two major improvements in wash-and-wear garments: (1) the use of crosslinking resins on cotton containing garments, and (2) the use of synthetics and synthetic blends. Although these two implementations have made major strides in reducing the wrinkling of a garment, consumers are still dissatisfied with the results and feel a need to iron.

The term "ease of ironing and improved appearance after ironing" as used herein means that a fabric requires less effort to iron (i.e., improved glide of the iron and wrinkles are removed more easily) and has less wrinkles after a special cleaning operation followed by ironing than it would otherwise have after an ordinary cleaning operation and ironing.

It is, therefore, an object of the present invention to provide compositions which provide superior ease of ironing/appearance after ironing benefits to treated garments. This and other objects are obtained herein, and will be seen from the following disclosure.

This invention relates to fabric care compositions comprising a silicone gel agent for use in a fabric cleaning operation whereby an effective amount of said silicone gel is deposited on said fabric for ease of ironing and improved appearance after ironing.

This invention relates to silicone gel compositions for fabric ease of ironing and improved appearance after ironing. In another respect this invention relates to methods of using such silicone gels compositions in the care of fabrics for improved ease of ironing and improved appearance after ironing. Preferred compositions are aqueous liquids which can also include a fabric softener and/or a surfactant. Such compositions are usually added to either the wash or rinse water of a laundering operation. These preferred compositions are aqueous based, water-dispersible additives which contain from about 0.1% to about 80%, more preferably from about 0.1% to about 50% of the silicone gels. The additives are diluted in the wash or rinse.

Surprisingly, the silicone gels plus a suitable carrier to deposit an effective amount of the silicone gel on fabric are excellent for ease of ironing and improved appearance after ironing. Accordingly, several fabric care compositions containing silicone gels are herein disclosed. Several methods of using silicone gels for ease of ironing and improved appearance after ironing fabric care are also disclosed.

The silicone gel compositions of this invention are used with a suitable carrier. The term "carrier" as used herein means any suitable vehicle (liquid, solid or mechanical) that is used to deliver the silicone gel and deposit it on the fabric. E.g., the silicone gel can be incorporated into an aqueous based softener or detergent composition, or an aqueous emulsion. It can be used in a bottled liquid spray. The preferred embodiments comprise: a liquid rinse water composition comprising the silicone gel plus fabric softener.

In a preferred execution, about 0.1% to about 10% by weight of a silicone gel is mixed into a suitable commercially available laundry liquid fabric softener composition. The result is a fabric care composition that provides an improved ease of ironing and improved appearance after ironing benefit to the treated fabric.

In another execution, a similar amount is mixed into a suitable commercially available liquid detergent and/or softener composition (anionic/nonionic surfactant based detergent, e.g., Liquid TIDE.RTM., or a nonionic surfactant based detergent, e.g., BOLD.sub.3 Liquid.RTM.). Care must be taken to use silicone gel emulsifiers compatible to the detergent surfactants to avoid deemulsification of the silicone gel. The new liquid detergent/silicone gel product provides an unexpected ease of ironing and improved appearance after ironing benefit. In yet another execution, the silicone gel can be sprayed directly on moistened fabric. In the wash or rinse liquid, the level of silicone gel should be about 1-300 ppm, preferably 5-150 ppm. In a direct spray on application, the silicone gel level could be higher, e.g., 1,000 ppm to 200,000 ppm.

While not wishing to be bound by theory, these silicone gels once deposited on the fabric are believed to spread and form a three-dimensional film on the fabric during the laundering process which aids in ease of ironing, wrinkle removal during ironing, and better appearance of the fabric after ironing.

Preferably, care should be taken to insure that the compositions of the present invention are essentially free of heavy waxes, abrasives, fiberglass, and other fabric incompatibles.

Silicone gels are somewhat of a cross between silicone fluids and silicone resins. Silicone fluids are by definition flowable silicone polymers of varying viscosities that can be branched or linear. Where typically, silicone resins are highly crosslinked siloxane solid systems with the crosslinking components introduced as tri-functional (T) (e.g., RSiO.sub.1.5) or tetra-functional units (Q) (e.g., SiO.sub.2). As one increases the tri- or tetra-(quatz) functional units without increasing the mono-functional or terminal component (M) (e.g., R.sub.3 SiO.sub.0.5), the resin becomes more brittle.

Most importantly for this invention, as one increases the di-functional units (D) (e.g., R.sub.2 SiO), the resin becomes softer and eventually is considered a silicone gel. In addition to the influence of mono-, tri-, tetra-, and di-functional units on the silicone resins and gels, their characteristics can also be influenced by changing the organic group. The terms Q, tetra-, and quat- are synonymous. While not being too limiting, typical silicone resins and gels use methyl, phenyl, vinyl, and mixtures thereof as the organic groups. Other possible groups, but not limiting, include amines (primary, secondary, tertiary, quaternary, cyclic, diamines and triamines), epoxides, esters, ethers, halo functional organics, carboxy, and even hydrogen.

The silicone gel important for this invention is very soft as compared to resins and has a lower level of crosslinking (i.e., a lower level of tri- (T) and/or tetra- (Q) functional units) as compared to silicone resins. The silicone gel of this invention also has a higher level of crosslinking as compared to a silicone fluid or a viscous silicone gum. More specifically, a preferred silicone gel has from about 3% to about 30% T and/or Q functional units, from about 70% to about 97% D functional units, and from 0% to about 10% M functional units; preferably, the silicone gel has from about 5% to about 20% T and/or Q functional units, from about 80% to about 95% D functional units, and from 0% to about 8% M functional units. More preferably, the silicone gel has from about 5% to about 15% T and/or Q functional units, from about 85% to about 95% D functional units, and from 0% to about 5 % M functional units. The polymeric silicone gel should have a molecular weight greater than about 20,000; greater than about 50,000; even greater than about 100,000; The molecular weight of the silicone gel can be greater than about 500,000.+-.400,000, and even greater than about 1,000,000. The important factor is that the silicone is a gel. At higher levels of the T and/or Q functional units, the molecular weight of the gel can be lower.

In addition, the silicone gel must be in a form in which it can be delivered to the laundered fabric, preferably via an aqueous vehicle; thus an emulsified form is very desirable. While not limiting the emulsification of a preformed gel, the generation of the silicone gel itself in an emulsion is a preferred method of making the preferred embodiment of this invention.

This can be accomplished by many different methods. Two general methods are: (1) emulsion polymerization (see U.S. Pat. No. 4,600,436, Traver/Thimineur/Zotto, issued July 15, 1986, for Durable Silicone Emulsion Polish, incorporated herein by reference, particularly col. 6, 11. 35-47); and (2) emulsification of polymers followed by curing in the emulsion (see "Silicones," by Hardman et al., Encyclopedia of Polymer Science and Engineering, Vol. 15, Second Edition, pages 204-308, John Wiley and Sons, Inc., 1989, also incorporated herein by reference). There are four methods of curing set out in Harding et al.: (1) condensation; (2) peroxide; (3) platinum-catalyzed hydrosilation; and (4) Uv. These curing methods are known in the art, however, one must take care in picking the starting materials and reaction conditions to insure obtaining the desired "gel."

One specific method of the generation of a gel is to first emulsify a curable branched silicone polymer, then cure the polymer to a gel within the emulsion droplet before delivering to the fabric. For example: an emulsified branched curable amine functional silicone (experimental emulsion supplied by General Electric Co., No. 124-7701, which is a 20% emulsion of a GE commercially available curable amine functional silicone, sold under the trade name SF 1706) at a pH of 9 to 10 heated at 50.degree. C. in a glass container for 5 to 10 days yields an emulsified silicone gel.

The silicone gel is made from a branched curable amine functional silicone having the following structure:

wherein X is equal to Z+2; and Y is at least 3; and wherein Z is at least 1; wherein R', R" is a C.sub.1-20 alkyl or an amine group selected from cyclic amines, polyamines and alkylamines having from about 2 to about 7 carbon atoms in their alkyl chain, and wherein at least R' or R" is an amine group; and wherein the curable amine functional silicone is cured in an emulsified form by heat and/or the addition of base to form an emulsified silicone gel.

A preferred silicone is when: R is a hydrogen or a C.sub.1-3 alkyl; R' is C.sub.1-3 alkyl; and R" is an alkylamine group having from about 2 to about 7 carbon atoms in its alkyl chain; and wherein the curable amine functional silicone is cured in an emulsified form by heat and/or the addition of base to form an emulsified silicone gel.

The more preferred silicone is when: R is methyl; R' is methyl; R" is (CH.sub.2).sub.3 NH(CH.sub.2).sub.2 NH.sub.2 ; X is about 4; Y is about 27 and Z is about 2; and wherein said silicone has a molecular weight in the range of from about 1,000 to about 2,800 and a viscosity of about 5-40 centistokes at 25.degree. C.; and wherein the curable amine functional silicone is cured in an emulsified form by heat and/or the addition of base to form an emulsified silicone gel.

The physical properties of this system are vastly different than those of the starting polymer. The advantages of using the curable amine functional silicones for wrinkle reduction have been previously disclosed in U.S. Pat. Nos.: 4,800,026, Coffindaffer/-Wong, issued Jan. 24, 1989; 4,911,852, Coffindaffer/Trinh issued Mar. 27, 1990; and 4,923,623, Coffindaffer, issued May 8, 1990, all of said patents incorporated herein by reference, in which a polymer is delivered to the fabric and then permitted to cure by reacting with other silicones. Much to our surprise, if one cures the polymer to form a gel in the emulsion and then delivers the gel via a liquid vehicle, ease of ironing and improved appearance after ironing benefits can be achieved that are consumer noticeable.

The reaction time of producing the gel disclosed above can be decreased by increasing the pH of the emulsion. For example, at pH of 13, the gel of emulsified SF 1706 can be formed in 6 to 30 hours depending on the desired degree of cure before addition to product. An increase in temperature to ambient up to about 75.degree. C. .+-.15.degree. C. can also increase the rate of the curing reaction while a decrease in pH slows the curing reaction rate, e.g., at a pH of about 2.5, almost no curing takes place after one month at 23.degree. C. Care should be taken to keep the temperature low enough so as to keep the emulsion intact.

In this reaction, the amine and base in the system act as the catalysts for the condensation curing reaction. The effectiveness of alkali metal hydroxides as catalysts increases in the order Li.sup.+ <Na.sup.+ <K.sup.+ <Rb.sup.+ <Cs.sup.+. Many other methods which do not require the use of amines or bases for curing silicone polymers are well-known in the art, some of which are disclosed in the Encyclopedia of Polymer Science and Engineering. Vol. 15, Second Edition, pages 204-308, John Wiley and Sons, Inc., 1989, and thus incorporated herein by reference.

One method of characterizing silicone gels is .sup.29 Si; NMR. Even in the emulsified form (with a relaxation aid such as Cr(acac).sub.3), M, D, T and Q are easily identified in the ranges specified above.

The fabric care composition of this invention comprises a suitable silicone gel, and, preferably, another fabric care material, e.g., one selected from organic solvents, water, surfactants, fabric softeners, soil release agents, builders, brighteners, perfumes, dyes, and mixtures thereof.

One embodiment of the present invention is a liquid fabric softener composition comprising an effective amount of a silicone gel and a fabric softener selected from the softeners disclosed in U.S. Pat. No. 4,661,269, Trinh et al., issued Apr. 28, 1987, incorporated herein by reference. U.S. Pat. No. 3,904,533, Neiditch et al., issued Sept. 9, 1975, incorporated herein by reference, teaches a number of other fabric conditioning formulations suitable for the present invention.

Another embodiment of the present invention is a liquid detergent composition comprising an effective amount of silicone gel and a surfactant, e.g., one selected from those disclosed in U.S. Pat. Nos.: 4,318,818, Letton et al., issued Mar. 9, 1982, and 4,911,852, Coffindaffer/Trinh, issued Mar. 27, 1990, both incorporated herein by reference. A suitable surfactant can be selected from anionic, nonionic, amphoteric, zwitterionic and cationic surfactants, and mixtures thereof. In preferred executions, the addition of from about 0.1% to about 33%, preferably from about 0.5% to about 20%, and, more preferably from about 1.0% to about 10% of the silicone gel by weight of the total liquid detergent composition can result in a product that provides outstanding ease of ironing and improved appearance after ironing benefits when fabric is washed therein in the usual manner.

The preferred composition of this invention is an aqueous dispersion comprising: a silicone gel wherein the silicone gel to fabric softener has a weight ratio of from about 17:1 to about 1:350, preferably from about 10:1 to about 1:100. Some more preferred weight ratios of silicone gel to fabric softener are from 1:1 to 1:10 and from 1:5 to 1:10. These compositions are added to the rinse water for ease of ironing and improved appearance after ironing and fabric softening benefits.

Suitable fabric softener(s) are selected from the group consisting of:

i. quaternary ammonium compound;

ii. fatty amine fabric softening compound;

iii. fatty amide compound;

iv. fatty acids;

v. fatty alcohols; and

vi. mixtures thereof.

In certain liquid rinse-added compositions of this invention the amount of fabric softener can range from about 2% to about 35%, preferably from about 4% to about 27%, by weight of the total composition. The lower limits are amounts needed to contribute effective fabric softening performance when added to laundry rinse baths in the manner which is customary in home laundry practice. The higher limits are suitable for more concentrated liquid products which require smaller volume usage.

The preferred levels of silicone gel in such composition can range from about 0.05% to about 40%; from about 0.1% to about 20%; and from about 0.5% to about 10% by weight of the concentrate.

Suitable fabric softener compounds include quaternary ammonium salts, as well as nonquaternary amines and amine salts.

Compositions containing cationic nitrogenous compounds in the form of quaternary ammonium salts and substituted imidazolinium salts having two long chain acyclic aliphatic hydrocarbon groups provide fabric softening benefits when used in laundry rinse operations. (See, for example, U.S. Pat. Nos. 3,644,203, Lamberti et al., issued Feb. 22, 1972; and 4,426,299, Verbruggen, issued Jan. 17, 1984; also "Cationic Surface Active Agents as Fabric Softeners," R. R. Egan, Journal of the American Oil Chemists' Society, January 1978, pages 118-121; and "How to Choose Cationics for Fabric Softeners," J. A. Ackerman, Journal of the American Oil Chemists' Society, June 1983, pp. 1166-1169).

Other suitable fabric softening compounds are the nonquaternary amides and the nonquaternary amines. A commonly cited material is the reaction product of higher fatty acids with hydroxy alkyl alkylene diamines. An example of these materials is the reaction product of higher fatty acids and hydroxyethylethylenediamine (See "Condensation Products from beta-hydroxyethylethylenediamine and Fatty Acids or Their Alkyl Esters and Their Application as Textile Softeners in Washing Agents," H. W. Eckert, Fette-Seifen-Anstrichmittel, September 1972, pages 527-533). These materials are usually cited generically along with other cationic quaternary ammonium salts and imidazolinium salts as softening actives in fabric softening compositions. (See U.S. Pat. Nos. 4,460,485, Rapisarda et al., issued July 17, 1984; 4,421,792, Rudy et al., issued Dec. 20, 1983; 4,327,133, Rudy et al., issued April 27, 1982).

A particularly preferred fabric softener is in the form of an aqueous dispersion comprising from about 3% to about 35% by weight of a mixture consisting of:

(a) from about 10% to about 92% of the reaction product of a higher fatty acid with a polyamine selected from the group consisting of hydroxyalkylalkylenediamines and dialkylenetriamines and mixtures thereof, and

(b) from about 8% to about 90% of cationic nitrogenous salts having only one long chain acyclic aliphatic C.sub.15 -C.sub.22 hydrocarbon group, and optionally

(c) from 0% to about 80% of a cationic nitrogenous salt having two or more long chain acyclic aliphatic C.sub.15 -C.sub.22 hydrocarbon groups or one said group and an arylalkyl group having from about 15 to about 22 carbon atoms in its alkyl chain.

For a detailed description of some preferred fabric softeners, see commonly assigned U.S. Pat. No. 4,661,269, Trinh/Wahl/Swartley/ Hemingway, issued Apr. 28, 1987, incorporated herein by reference in its entirety.

The terms herein, e.g., softener compound, in general, denotes both singular and plural unless otherwise specified.

Preferred carriers are liquids selected from the group consisting of water and mixtures of the water and short chain C.sub.1 -C.sub.4 monohydric alcohols. The water which is used can be distilled, deionized, or tap water. Mixtures of water and up to about 10%, preferably less than about 5%, of a short chain alcohol such as ethanol, propanol, isopropanol or butanol, and mixtures thereof, are also useful as the carrier liquid.

Some short chain alcohols are present in commercially available quaternary ammonium compound products. Such products can be used in the preparation of preferred aqueous compositions of the present invention. The short chain alcohols are normally present in such products at a level of from about 1% to about 10% by weight of the aqueous compositions.

Other carriers are suitable solids, polyol waxes and wax-like materials commonly used in the detergent and dryer-added softener fields and spray containers.

Compatible adjuvants can be added to the compositions herein for their known purposes. Such adjuvants include, but are not limited to, viscosity control agents, perfumes, emulsifiers, preservatives, antioxidants, bactericides, fungicides, colorants, dyes, fluorescent dyes, brighteners, opacifiers, freeze-thaw control agents and shrinkage control agents, and other agents to provide ease of ironing (e.g., starches, etc.). These adjuvants, if used, are added at their usual levels, generally each of up to about 5% by weight of the preferred liquid composition.

Viscosity control agents can be organic or inorganic in nature. Examples of organic viscosity modifiers are fatty acids and esters, fatty alcohols, and water-miscible solvents such as short chain alcohols. Examples of inorganic viscosity control agents are water-soluble ionizable salts. A wide variety of ionizable salts can be used. Examples of suitable salts are the halides of the group IA and IIA metals of the Periodic Table of the Elements, e.g., calcium chloride, magnesium chloride, sodium chloride, potassium bromide, and lithium chloride. Calcium chloride is preferred. The ionizable salts are particularly useful during the process of mixing the ingredients to make the liquid compositions herein, and later to obtain the desired viscosity. The amount of ionizable salts used depends on the amount of active ingredients used in such compositions and can be adjusted according to the desires of the formulator. Typical levels of salts used to control the composition viscosity are from about 20 to about 6,000 parts per million (ppm), preferably from about 20 to about 4,000 ppm by weight of the composition.

Typical levels of compatible bactericides used in the present compositions are from about 1 to about 1,500 ppm by weight of the composition.

Examples of antioxidants that can be added to the compositions of this invention are propyl gallate, available from Eastman Chemical Products, Inc., under the trade names Tenox.RTM. PG and Tenox S-1, and butylated hydroxy toluene, available from UOP Process Division under the trade name Sustane.RTM. BHT.

The compositions may contain noncurable silicone fluids to provide additional benefits such as improved fabric feel. The preferred adjunct silicones are polydimethylsiloxanes of viscosity of from about 100 centistokes (cs) to about 100,000 cs, preferably from about 200 cs to about 60,000 cs. These adjunct silicones can be used as is, or can be conveniently added to the softener compositions in a preemulsified form which is obtainable directly from suppliers. Examples of these preemulsified silicones are 60% emulsion of polydimethylsiloxane (350 cs) sold by Dow Corning Corporation under the trade name DOW CORNING.RTM. 1157 Fluid and 50% emulsion of polydimethylsiloxane (10,000 cs) sold by General Electric Company under the trade name General Electric.RTM. SM 2140 Silicones. The optional silicone component can be used in an amount of from about 0.1% to about 6% by weight of the composition.

A preferred composition contains from about 1 ppm to about 1,000 ppm of bactericide and from about 0.2% to about 2% of perfume, from 0% to about 3% of polydimethylsiloxane, from 0% to about 0.4% of calcium chloride, from about 10 ppm to about 100 ppm of dye, and from 0% to about 10% of short chain alcohols, by weight of the total composition.

The pH of the preferred compositions of this invention is generally adjusted to be in the range of from about 2 to about 11, preferably from about 2 to about 8. Adjustment of pH is normally carried out by including a small quantity of free acid or free base in the formulation. Any acidic material can be used; its selection can be made by anyone skilled in the softener arts on the basis of cost, availability, safety, etc. Any suitable acid can be used to adjust pH. Preferred are hydrochloric, sulfuric, phosphoric and formic acid. Similarly, any suitable base, e.g., sodium hydroxide, can also be used to adjust pH. For the purposes of this invention, pH is measured by a glass electrode in full strength softening composition in comparison with a standard calomel reference electrode.

The compositions of the present invention can be prepared by a number of methods. Some convenient and satisfactory methods are disclosed in the following nonlimiting examples.

A liquid fabric softener composition containing a silicone gel is prepared in the following manner. 4.33 parts di(hydrogenated tallow)dimethylammonium chloride (DTDMAC), 1.00 part methyl-1-tallow amidoethyl-2-tallowimidazolinium methylsulfate and 0.025 parts dye are weighed into a premix vessel.

After heating to 75.degree. C. and mixing, the premix is added with agitation, to a mix vessel44.degree. C.) containing 88.14 parts distilled water and 0.025 parts antioxidant solution. Then 0.45 parts of perfume is added to this "main" mix. The main mix is then cooled to 21.degree. C., to which is added with stirring 5.0 parts emulsified silicone gel (20%) silicone).

Same as Procedure A, except that the emulsified silicone gel is incorporated into the main mix prior to cooling of the mix to 21.degree. C.

The ratios of polymeric silicone gel to total fabric softeners is about 1:5. The molecular weight of the polymeric silicone gel is at least about 100,000, and some gel particulates may have molecular weights estimated to be greater than 1,000,000. The functional units of this silicone gel are about 10% T and Q; 88% D and 2% M with an estimated .+-.15% relative for each level.

A silicone gel and fabric softener composition is prepared using Procedure A. The ingredients are: 2.00 parts Mazamide 6, 0.80 parts MTTMAC, 4.03 parts DTDMAC, 1.00 parts imidazolinium salt, 0.42 parts perfume, 1.28 parts alcohol (from actives), 10.00 parts 20% emulsified silicone gel, and the balance in distilled water. See Table 2 and Example I for a recap of the ingredients and method of preparation. The ratio of silicone gel to total fabric softener is about 1:7.

A silicone gel and fabric softener composition is prepared using Procedure A. The ingredients are: 17.50 parts Mazamide 6, 6.50 parts DTDMAC, 1.32 parts perfume, 2.07 parts alcohol (from actives), 12.00 parts 20% emulsified silicone gel, and the balance in distilled water. See Table 2 and Example I for a recap of the ingredients and method of preparation. The ratio of gel to total softener is about 1:10.

An amine functional silicone gel (AFSG) and fabric softener composition is prepared using Procedure A. The ingredients are: 3.75 parts DTDMAC, 3.40 parts imidazoline, 0.57 parts MTTMAC, 0.40 parts perfume, 0.025 parts dye, 0.77 parts alcohol (from actives), 0.4-0.9 parts HCl, 5.00 parts AFSG and the balance is distilled water.

A fabric softener composition is prepared as in Product BM, except no AFSG is added.

See Table 3, Example IV for a recap of ingredients for products BM & D.

Products BM & D were used as rinse-added fabric softeners to treat poly cotton (65%/35%) and 100% cotton fabrics. The fabrics were treated with five successive wash/rinse/dry treatments. The detergents used were TIDE.RTM. and Liquid TIDE.RTM.. Forty-eight sets of swatches saw only TIDE and twenty-five only Liquid TIDE. Keeping the Liquid TIDE and TIDE washed fabrics separate, panelists were asked to iron one of each fabric type for each treatment and choose which were the easiest to iron. After ironing, the fabrics were placed on a hanger and judged for appearance (least wrinkled). The "no preference" votes were divided in half and split evenly among the treatments. Results are summarized below.

The incorporation of emulsified silicone gel into the exemplified fabric softener compositions improves the ease of ironing and the appearance of laundered fabrics (e.g., Product BM vs. Product D). The fabric care compositions of this invention work very well on laundered polyesters, cottons and cotton/polyester blends.