Method and composition for treating fibrous substrates to impart oil, water and dry soil repellency

[0002] The present invention relates to a method and composition for treating fibrous substrates, to thereby impart oil, water and soil repellency at substantially reduced add on levels of typical fluorochemical products useful in imparting those properties. Fluorochemicals are generally comprised of at least one fluorine containing resin and at least one non-fluorine containing resin which when co-applied to a fibrous substrate provide a durable film on the surface of the fibrous substrate the film may be either continuous or discontinuous in nature so as to cover all or part of the surface of the fibrous substrate.

[0003] In this disclosure it is of particular importance to distinguish the differences that exist between the terms A) soil repellency B) oil repellency and C) water repellency, as they relate to textiles.

[0004] A) Soil repellency refers to the ability of a fibrous substrate to resist the adhesion of dry soils. The tests performed to evaluate soiling performance levels generally involve applying standardized non liquid containing dry soil compositions to a fibrous substrate and further subjecting it to a moving load to simulate wear or trafficking and subsequently submitting the soiled substrate to a specified soil removal process, such as vacuuming. These tests may also involve water extracting. The substrate is then compared to a control sample or standard of established value.

[0005] B) Oil repellency refers to the degree to which a substrate repels liquids of this type. Typically AATCC test method 118-1983 is used to determine oil repellency values from ‘1’ to ‘8’ where in ‘8’ is the highest repellency rating.

[0006] C) Water repellency refers to the degree to which a substrate repels water and water/isopropanol mixtures and is determined using a similar method to that for oil repellency.

[0007] The extensive and preferred application of fluorochemicals to provide fibrous substrates with water, oil and soil repellency has led to the use of oil and water repellency values to be deemed directly proportional to soil repellency values and this is often not true.

[0008] The significance of each type of repellency value is for example, directly related to the type of repellency required for a particular textile end use. An awning type material that is exposed to the elements will derive maximum benefit from a high level of water repellency and a low to no oil repellency level but to maintain an acceptable appearance it should be provided with high soil repellency. Surgical gowns, masks and other such clothing, which are for the most part disposable, require high levels of oil and water repellency to prevent liquid penetration but require little if any soil repellency. Carpeting on the other hand requires moderate levels of oil and water repellency to fend off occasional spills but requires the highest level possible of soil repellency to promote effective and easy maintenance.

[0009] The diverse end use requirements for oil, water and soil repellency has led to a wide variety of fluorochemicals being developed. They provide a wide variation in the type of protection and levels of protection offered. It is therefore of major benefit to have a range of fluorochemical products which at point of application to a fibrous substrate can be provided with admixture components and process parameters that will reduce by up to 60% the quantity of fluorochemicals required to obtain certain specified levels of oil, water, and soil repellency.

[0010] It is the focus of this disclosure to provide a method and compositions for treating fibrous substrates whereby the amount of fluorochemicals required may be reduced by up to 60% while maintaining specified levels of repellency for a given fibrous substrate.

[0011] Processes have already been described such as in Canadian Patents Nos. 832,401 of Bey issued Jan. 20, 1970 and 830,886 of Mohrlok et al issued Dec. 30, 1969 and German published specification DE-OS No. 1,594,985 for treating fibrous substrates to render them repellent to dry soil by applying thereto a colloidal suspension of silsesquioxanes which consist of R SiO_3/2units and have a particle size of 10 to 1,000 Angstroms.

[0012] U.S. Pat. No. 4,351,736 of Steinberger et al issued September 28, 1982, further provides for a textile impregnating agent useful for pile stabilization and a process for its preparation comprising a colloidal suspension of a silicic acid with SiO₂units and organosilsesquioxanes having units of the formula R SiO_3/2wherein R is an alkyl or aryl radical with up to 7 carbon atoms and an average particle size of about 200 to 500 Angstroms and wherein the solids range from about 2% to about 9% by weight. This U.S. patent also teaches that the same textile impregnating agent provides significantly higher levels of soil repellency than that provided by DE-OS No. 1,594,985 type agents.

[0013] U.S. Pat. No. 4,781,844 of Kortmann et al issued November 1, 1988, describes further use of colloidal suspensions of organosilsesquioxanes described in U.S. Pat. No. 4,351,736 by combining those colloidal suspensions in specific ratios with certain perfluoroalkyl group containing resins within a specified range of resin solids content, to provide a textile finishing agent which, when diluted in and applied to a textile substrate and dried at elevated temperature, results in improved oil, water and soil repellency, over and above that of the described fluorochemical resins when applied in the same weight percent to a fibrous substrate without the addition of the described organosilsesquioxanes. This patent makes no reference to the possibility of fluorochemical reduction, based on weight of the fibrous substrate, resulting from the application of the prepared fibrous substrate finishing agent comprised of certain specified materials, in fixed ratios of weight percent to one another.

[0014] According to the present invention it has been discovered that an aqueous sol dispersion comprising solid organosiloxane co-polymers consisting of R SiO_{{fraction (3/2)}} units and/or R′₂SiO units and/or R″₃SiO_½ units wherein each of R, R′, R″ is from the group consisting of hydrocarbon and substituted hydrocarbon radicals containing from 1 to 7 carbon atoms and having an overall particle size range of from about 10 Angstroms to about 2,000 Angstroms and about 5% to about 26% typical solids by weight, when applied to a fibrous substrate according to the method herein after described in fact provides for substantial reductions in the amount of fluorochemical required to impart oil, water and soil repellency levels as specified by the intended end use of a particular fibrous substrate.

[0015] More particularly, in accordance with the present invention there is provided a method of treating fibrous substrates to thereby impart oil, water and dry soil repellency at substantially reduced add on levels of fluorochemicals based on the weight of a fibrous substrate so treated. The method comprises the steps of applying an aqueous treating medium comprising an admixture of:

[0016] (a) 0.1 to 35 parts by weight of an aqueous colloidal sol dispersion containing from about 5% to about 26% by weight solid organosilsesquioxane co-polymers having units selected from the group consisting of R SiO_{{fraction (3/2)}}, R′₂SiO and R″₃SiO_½ units, wherein each R, R′ and R″ radical is selected from the group consisting of hydrocarbon and substituted hydrocarbon radicals containing from 1 to 7 carbon atoms, the co-polymers having an overall particle size range of from about 10 Angstroms to about 2000 Angstroms in a sufficient amount to yield from 0.04% to 0.32% solids based on the weight of the fibrous substrate to which it is applied;

[0017] (b) from 0.00 to about 0.96 parts by weight of solids of fluorochemical resins selected from the group of liquids containing at least one dispersed or emulsified fluorine containing resin, added as an aqueous fluorochemical dispersion or emulsion wherein the fluorine content of the resin is from about 15% to 50% by weight in a sufficient amount to yield from about 100 parts per million to about 500 parts per million fluorine atom on the fibre; and

[0018] (c) 64.04 parts to 99.9 parts by weight of a diluent, and then heating the fibrous material to cause curing of resin components so applied.

[0019] In a preferred embodiment of the present invention, incorporated in the diluent is an effective amount of fibrous substrate agent selected from the group consisting of leveling agents, anti foams, foaming agents, stain blockers, spin finish, acids, bases and salts.

[0020] It will be understood that the solid organosiloxane co-polymers materials themselves do not produce water or oil repellency. Their presence however in the treating medium for the fibrous substrate extends the repellency qualities of the fluorochemical resins so that significant reductions in the amounts of fluorochemical resins used, to achieve comparable repellency on the substrate are significantly reduced.

[0021] Some terms used within this disclosure are further listed and defined hereunder as an aid to the reader.

[0022] Fluorochemical resins as supplied to the textile industry for the purpose of imparting oil, water or soil repellency or a combination of said repellencies, are generally of sufficient active content to be applied to a textile fibre at from about 0.25% to about 1.0% based on weight of fibrous substrate.

[0023] It is further generally accepted that the resultant fluorine deposited onto a fibrous substrate from the application thereto of a fluorochemical resin, to provide acceptable to high, combined oil, water and soil repellency, will range from about 300 to about 500 parts per million by weight.

[0024] The method and composition for treating fibrous substrates in accordance with the present invention, is intended for fibrous substrates that normally derive an original marketable benefit of:

[0025] a) enhanced soil repellency values or

[0026] b) enhanced water repellency values or

[0027] c) enhanced oil repellency values or

[0028] d) any combination of a), b), or c)

[0029] from the application there to of a fluorochemical resin in an amount based on weight of said fibrous substrate and may, by the use of said method and compositions further derive a financial or other marketable benefit from a reduction in the amount of fluorochemical resin used of from about 30% to about 60% based on weight of said fluorochemical resin, while maintaining or improving the original marketable repellency benefits.

[0030] In order to provide accurate demonstrations of fluorochemical resin reductions based on the weight of fibrous substrates it is necessary to assure that the fluorochemical resin is evenly applied to the entire fibrous substrate and not to a portion thereof, such as is common practice in many textile operations. High pile fibrous substrates such as carpeting for example normally make use of topical spray or topical foam applications of fluorochemical resin and such application techniques seldom apply fluorochemical to more than 75% of the fibrous substrate. As well, the consistency of penetration into the substrate can vary widely within any particular production run. It is therefore somewhat difficult to provide accurate data based on weight of fibrous substrate using these application techniques, however using direct comparative test data from such techniques while still referencing fibrous substrate weight will demonstrate the practical usefulness of this invention in its broadest terms of reducing the quantity of fluorochemical resin or resins required to achieve a particular level of repellency.

[0031] Fibrous substrate manufacturers and yam converters on the other hand rely on even and consistent applications of lubricants, coding tints and fluorochemical resins which are added in specific amounts based on weight of the fibre or yam. The method and composition of this invention makes use of typical fibre or fibrous substrate processing procedures or both to achieve significantly reduced overall add-on levels of fluorochemical resins based on weight of fibrous substrate.

[0032] The method as it applies to a textile fibre may be practiced by application of the composition within a spin finish that is either metered or sprayed onto a fibre or yarn and is subsequently subjected to elevated temperatures sufficient to cure the fluorochemical resins contained therein, such as those attained in the drawing, texturizing or heatsetting processes, before further manufacturing into a fibrous substrate such as carpet, furniture fabric or garment etc. The substrate, containing fibres or yarns so processed, may have as a final step, a further application of one or more of the disclosed components of the composition providing that certain limiting overall weight percentages of said organosiloxane co-polymers on weight of fibre or yam are maintained within the disclosed range.

[0033] The method of this invention as it applies to a textile substrate may be practiced by: exhaustion from a liquor, low wet pick up padding, high wet pick up padding, topical spray, topical foam or a combination of such processes providing the substrate is subsequently subjected to elevated temperatures prior to any further wet processing and that certain limiting overall weight percentages of said described organosiloxane co-polymer units on weight of substrate are maintained within the disclosed range. The method and composition allows for co-application with other textile agents imparting or providing other properties to a fibrous substrate, such as stain resistance, wrinkle resistance, UV protection, hand modification, colour, etc. Certain textile agents in fact enhance the repellencies when co-applied.

[0034] The following is a summary of textile agents used in demonstrating this invention.

[0035] Fluorochemicals

[0036] F1—Type FX-1367* Anionic Electrochemically Fluorinated, Flurorpolymer

[0037] Emulsion

[0038] Sold by 3M Specialty Chemical Division.

[0039] Approximately 41% solids

[0040] Approximately 59% medium

[0041] F2—Type TG-3020* Anionic Fluoropolymer Emulsion

[0042] Sold by Daikin Industries Ltd.

[0043] Approximately 30% solids

[0044] Approximately 70% medium

[0045] F3—Type TG232D* Nonionic, Fluoroalkyl Acrylate, Fluoropolymer Emulsion

[0046] Sold by Advanced Polymers Inc.

[0047] Approximately 30% solids

[0048] Approximately 70% medium

[0049] Trade-mark

[0050] F4—Type APG-160* Cationic Fluoropolymer Emulsion

[0051] Sold by Advanced Polymers, Inc.

[0052] Approximately 22% solids

[0053] Approximately 78% medium

[0054] F5—Type APG-559* Cationic Fluoropolymer Emulsion

[0055] Sold by Advanced Polymers, Inc.

[0056] Approximately 30% solids

[0057] Approximately 70% medium

[0058] Stain Blockers

[0059] SB1—“FX661”*, Principal ingredient Methacrylic Acid Resin

[0060] Sold by 3M Specialty Chemicals Division

[0061] SB2—“FX668F”* Principal ingredient Methacrylic Acid Resin

[0062] Sold by 3M Specialty Chemicals Division

[0063] SB3—“FX369”* Principal ingredient Phenolic-Resin

[0064] Sold by 3M Speciality Chemicals Division

[0065] SB4—“Algard NS”* Principal ingredient a Phenolic Resin

[0066] Sold by Hydrolabs Inc.

[0067] SB5—“SR300”* Principal ingredients Styrene-Maleic Anhydride Co-Polymer with a

[0068] Phenolic Resin

[0069] Sold by Dupont Flooring Systems

[0070] * Trade-mark

[0071] Colloidal Sol Dispersions of Organosiloxane Co-Polymers

[0072] DA1—16.4% solids, about 200 to about 500 Angstroms particle size range

[0073] DA2—5.8% solids, about 10 to about 1,900 Angstroms particle size range

[0074] DA3—17.5% solids about 10 to about 900 Angstroms particle size range

[0075] The following describes the test procedures followed in evaluating examples of this invention.

[0076] A. OIL REPELLENCY—According to AATCC Test Method 118-1983 and reported oil repellency values from ‘1’ to ‘8’ wherein ‘8’ is the highest repellency value.

[0077] B. WATER REPELLENCY—Test specimens are prepared and conditioned as per AATCC 118-1983, Test liquids prepared and numbered according to Table 1

[0078] The test sample is placed on a flat horizontal surface and a single droplets of each test liquid ‘0’ to ‘8’ is applied by means of eye dropper to various points on the test sample. The droplets are observed for 3 minutes. If no penetration or wetting of the fabric at the liquid-fabric interface and no wicking around the drop occurs, a drop of the next highest number test liquid is place at an adjacent site on the fabric and observed for 3 minutes. This process is continued until one of the test liquid shows obvious wetting of the fabric under or around the drop within 3 minutes. The repellency rating of a fabric is the highest number test liquid which will not wet the fabric within a 3 minute period (‘8’ is the highest repellency value).

[0079] C. SOIL REPELLENCY—Applicable to high pile substrates only such as carpeting and flocked materials. Samples are pre-conditioned for 48 hrs. at 70° F. and 65% relative humidity before testing. The test sample is placed in a cylinder with the back of the sample against the inside of the cylinder surface and the cylinder measuring 10 inches in diameter by 18 inches in length and closed at one end. Prepared soil in the amount of 20 grams is evenly distributed over the sample surface while manually rotating the cylinder. A total of 30 hard rubber balls measuring 0.75 inches in diameter are place in the cylinder and the cylinder is sealed. The cylinder is then placed on a motorized drum roller and caused to rotate at 50 RPM in one direction for 10 minutes and in the reverse direction for an additional 10 minutes. The sample is removed at the end of the 20 minute cycle and vacuumed cleaned so as to provide one complete vacuuming in each of 4 directions.

[0080] The sample is evaluated according to AATCC Test Method 121-1982 by comparing to an unsoiled standard sample of the same material using gray scale for colour change where in a “5” rating represents no soiling and a “1” rating represents heaviest soiling and a difference between two rating of 0.5 or greater is considered significant.

[0081] The soil was prepared according to AATCC Test Method 123-1982 with the addition of 0.5% by weight carbon black. A sufficient quantity was prepared in a single batch to complete all test requirements.

[0082] The following examples will illustrate the invention in more detail without limiting it.

[0083] A quantity of 100% nylon tufted carpet material ({fraction (1/10)} gauge, 26 oz/square yard loop pile) was scoured in a hot water bath at 180° F., at a 35 to 1 liquor ratio for 20 minutes, to simulate dying, then rinsed, extracted, dried and conditioned at 70° F. and 65% relative humidity for 24 hours and designated Sub. #1, and a portion retained as reference material for soil repellency tests.

[0084] Further portions of Sub. #1 were then impregnated in a low wet pick up padding method resulting in 50% wet pick up for each of the following treating solutions compositions and subsequently dried at 235° F. in a forced air oven and further conditioned at 70° F. and 65% relative humidity for 48 hours before testing as previously documented.

[0085] The composition by weight for each component of the treating solution was as follows in Table 2:

[0086] The treated samples were identified such that Solution #1 was applied to sample #1 and so on. Percent on weight of substrate is expressed as % of weight on goods (% owg). N/A means not applicable.

[0087] The results of tests performed on each sample are shown in Table #3, tests were performed as previously described herein.

[0088] A quantity of 100% dyed nylon tufted cut pile carpet material (⅛ gauge, 48 oz./square yard) was cut into samples, weighed, identified and applied with treating solution compositions as per Table #4 in a two step (‘A’ then ‘B’) process as follows:

[0089] Treating solutions ‘A’ as per Table #4 were adjusted to a pH of 2.5 to 3.5 and applied at 350% WPU, steamed at 210F for 60 seconds, extracted to about 40% wet content and further applied with topical spray applications of treating solutions ‘B’ as set out in Table #4 at 15% WPU, based on the dry weight of carpet then dried at 235° F. The samples were then conditioned and tested as previously documented and the results set out in Table #5. The reference for soil repellency evaluation in each case was the untreated, unsoiled carpet material.

[0090] A quantity of Multifiber Test Fabric No. 10A as specified in various AATCC Test Methods was used in the following samples to represent a range of common fibre types namely:

[0091] Spun Acetate=Fibre Type A

[0092] Bleached Cotton=Fibre Type B

[0093] Spun Nylon 6.6=Fibre Type C

[0094] Spun Dacron 54=Fibre Type D

[0095] Spun Orion 75=Fibre Type E

[0096] Worsted Wool=Fibre Type F

[0097] Samples of Multifiber Test Fabric were scoured as in Example #1, dried and slit into ribbons of individual fibre type and applied with treating solutions of compositions as set out in Table #6 by means of low wet pick up padding at 20% wet pick up on weight of material. The fabric was then dried at 235° F. and conditioned for 48 hours at 70° F. and 65% relative humidity before testing as previously described herein. The tests results are set out in Table #7.

[0098] A quantity of finished 100% nylon, tufted cut pile carpet material (⅛ gauge, 48 oz. per square yard) and an 80/20 wool-nylon blend, woven cut pile carpet material were cut into samples, weighed, identified as ‘N’ for nylon and ‘W’ for wool-nylon blend along with sample No. and applied with topical spray applications at 20% wet pick up on weight of goods of treating solutions at a pH of 4.0 and of compositions as set out in Table 8.

[0099] The samples were then dried at 235° F., conditioned and tested as previously documented with the results set out in Table 9. The reference for soil repellency evaluation in each case was the untreated, unsoiled finished carpet.

[0100] In summary, from the above tests, the results obtained from Examples #1 through #4 demonstrate that when synthetic or natural fibres are applied with the herein described organosiloxane co-polymers and either A) subsequently applied with a fluorochemical in a further process or B) simultaneously co-applied with a fluorochemical in a one step process; said described organosiloxane co-polymers provide for substantial reductions in the amount of fluorochemical otherwise (normally) required to impart oil, water and soil repellency of equivalent performance values.

[0101] It is also demonstrated in Examples #2 and #4 that said described organosiloxane co-polymers when co-applied with textile agents, described as stain blockers, to a synthetic or natural fibre and A) subsequently applied with a fluorochemical in a further second step, or B) is co-applied with a fluorochemical in a one step process. The resulting decrease in fluorochemical otherwise (normally) required to impart oil, water, and soil repellency is even further reduced over that previously observed.

[0102] Thus there has been provided in accordance with the invention a method and composition for treating fibrous substrates to impart oil, water and dry soil repellency that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with illustrated embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and broad scope of the invention.