US3782898A - Temporary soil release resins applied to fabrics in laundering - Google Patents

Abstract

A LAUNDERING PROCESS AND NOVEL LAUNDERING COMPOSITION USED TO IMPART TEMPORARY SOIL RELEASE PROPERTIES TO TEXTIILE FABRIICS BY IMPREGNATING THE FABRICS WITH AN ACRYLIC RESIN IN THE FINAL STEP OF A LAUNDERING OPERATION, USUALLY IN THE SOUR OPERATION. THE FABRICS ARE THAN DRIED LEAVING A RESIDUE OD F THE RESIN ON THE FABRICS WHICH HELPS REMOVE AFTER ACQUIRED STAINS. THE RESIN IMPREGNATION CAN BE COMBINED WITH FABRIC FINISHING TREATMENTS SUCH AS BLUEING, SIZING, BRIGHTENING AND SOFTENING. THE PROCESS IS REPEATED WITH EACH SUBSEQUENT LAUNDERING OF THE FABRICS TO OBTAIN OPTIMUM SOIL RELEASE AND STAIN REMOVAL. THE LAUNDERING COMPOSITIONS COMPRISES WATER, ACRYLIC RESIN, AND LAUNDRY SOUR OR OTHER FABRIC AGENT.

Description

United States Patent Office 3,782,898 Patented Jan. 1, 1974 3,782,898 TEMPORARY SOIL RELEASE RESINS APPLIED TO FABRICS IN LAUNDERING Harry Creston Mandel], Jr., Wayne, Pa., assignor to Pennwalt Corporation, Philadelphia, Pa. N Drawing. Filed Aug. 12, 1971, Ser. No. 171,362 Int. Cl. B08]: 3/00 US. Cl. 8-137 12 Claims ABSTRACT OF THE DISCLOSURE A laundering process and novel laundering composition used to impart temporary soil release properties to textile fabrics by impregnating the fabrics with an acrylic resin in the final step of a laundering operation, usually in the sour operation. The fabrics are then dried leaving a residue of the resin on the fabrics which helps remove after acquired stains. The resin impregnation can be combined with fabric finishing treatments such as blueing, sizing, brightening and softening. The process is repeated with each subsequent laundering of the fabrics to obtain optimum soil release and stain removal.

The laundering compositions comprise water, acrylic resin, and laundry sour or other fabric finishing agent.

BRIEF SUMMARY OF THE INVENTION Deeply set grease and oil stains have proved difficult to remove by laundering, especially in the synthetic fabrics made of polyester or mixtures of polyester and cotton. In accordance with this invention, I have discovered a method of treating textile fabrics with acrylic resins in the final stage of the laundering process which impregnates the fabrics with the resins to provide temporary soil release characteristics. The resin impregnation of the fabrics assists in the removal of deeply set stains and at the same time the fabric acquires soil resistant properties so that any subsequently acquired stain does not become deeply and permanently attached. The impregnated resin is largely removed in the next laundering of the fabric so that a new application of the resin must be made on each subsequent laundering to obtain and maintain optimum soil release capability.

The acrylic resins are added to the last stage of the laundering cycle which is usually the sour operation. Moreover, the resins could be added to other fabric finishing treatments such as blueing, sizing, brightening or softening provided it is the last operation. The concentration of the resin in the sour or other finishing solution will be an amount so that the quantity of resin left on the fabric after drying will provide an effectual means for removing soil and stains. This is known asan effective amount of acrylic resin. Generally, the concentration of the resin in the treating composition will be at least one-quarter part resin per 5,000 parts by weight of souring solution or other treating solution such as blueing, or sizing, A preferred concentration range is one-half to 1 part of resin per 5,000 parts of sour, or other treating solution while concentrations as high as 3 parts of resin per 5,000 parts of treating solution have been used for reclamation of deeply soiled garments.

The acrylic resin is generally an aqueous solution although some resins may be in the form of aqueous emulsions. The pH of the resin treating solution must be within the range of 4 to 6.5, preferably within a range of 4.5 to 6.0. The temperature during the impregnation treatment is not critical but is usually within the range of 70 to 180 F., preferably within the range of 95 to 180 F. These conditions of temperature and pH apply to either souring liquids or other fabric finishing treatment solutions in which the acrylic resin is suspended or is in solution.

The resin treating solutions are separated from the fabrics by conventional laundry practice leaving the fabrics wet and impregnated with resin. The fabrics are then dried by conventional laundry practice leaving the resin on the fabrics. Drying temperatures of to 350 F. are satisfactory. The amount of resin left on the fabric after drying is in the order of 0.005 to 0.05 percent by weight. A preferred amount of resin is 0.01 to 0.2% by weight on a dry basis.

Thus, the retained resin acts as a parting layer or film for subsequently acquired stains permitting their easy removal in subsequent laundering operations. The removal of the resin itself in subsequent laundering operations further increases the removal of soil and stains. Additionally, the impregnated resin attacks deeply seated stains and greases already present so that repeated treatments with the resin eventually restore a badly soiled fabric to a usable condition. Generally, about three launderings including a resin treatment in each cycle are required to restore a fabric. The acrylic resins used in my process are mixtures of one or more homopolymers and copolymers obtained from acrylic acid or methacrylic acid, and alkyl esters of acrylic acid and methacrylic acid.

The resin treating process is thoroughly compatible with present day laundering, and normal laundering conditions of temperature and detergent concentration for washing and rinsing precede the resin treatment of the fabrics.

Also in accordance with my invention, I have discovered novel resin compositions for treating fabrics during laundering to give them temporary soil release characteristics. These compositions comprise the acrylic resins discussed above in aqueous mixtures with laundry sours and/or fabric finishing agents such as blues, brighteners, sizing agents and softeners.

In a laundry souring solution, sufficient souring chemical must be present to give a pH within the range of 4 to 6.5 preferably within the range of 4.5 to 6.0. The same conditions of pH and acrylic resin concentration apply to other fabric finishing compositions comprising water, resin and fabric finishing agent such as blueing, sizing, brightener, or softener.

In another aspect of my invention, the acrylic soil release resin may be applied by spray to a textile fabric which has previously been dried. The spray propellant may be air, carbon dioxide, hydrocarbons or fiuorocarbons. The fabrics are dried after spraying to remove the spray liquid. The clothes may be dried on racks or by tumbling in an air-clothes dryer or by ironing. Drying temperatures may vary from room temperature to 350 F. Example 8 is illustrative of this aspect of my invention.

DETAILED DESCRIPTION OF THE INVENTION In recent years the use of fabrics which are made from blends of different textile fabrics has become increasingly common. One of the more popular of these mixtures is polyester with cotton fiber in a ratio frequently containing from 50 to polyester. These fabrics are frequently treated to provide improved strength to the cotton portion, to improve hand or quality of texture, to provide permanent press characteristics and to provide soil release characteristics.

It has been commonly observed that polyester and other synthetic fibers with or without premanent press or other resin finish are usually difiicult to clean in a conventional laundering operation. More particularly, polyester-cottons are especially susceptible to oily stains that become deeply set and are not easily removed. The polyester fibers are relatively hydrophobic and the conventional water laundering systems cannot penetrate the fabric to reach the stain and effect its removal.

Drycleaning is being used to remove these deeply set grease stains from treated or untreated mixed fiber blends, but drycleaning suffers from the disadvantage that it is relatively much more expensive than laundering and drycleaning does not readily remove the water soluble portion of the soil which is usually present in large quantities.

I have conceived a process of treating textile fabrics in the last step in a laundering process in such a way that greasy soil stains do not become deeply and permanently attached and are readily removed in subsequent laundering operations. The essence of my discovery is the temporary impregnation of the fabrics with an acrylic resin. The acrylic resin provides a means for flushing away subsequently acquired stains in the next laundering of the fabric. The resins are not permanently attached to the fabric and are generally nearly all removed in the next laundering. To the extent that the resins are not all removed in the next laundering they remain to assist in the removal of after acquired stains. Most of the applied resin is removed in the next laundering of the fabric so that a new application of the resin must be made on each subsequent laundering to obtain and maintain optimum soil release capability.

In addition to the ability to resist and facilitate the removal of subsequently acquired stains, the resin treatment which I have discovered assists in the removal of previously acquired deeply imbedded stains. I have observed that after two or three resin treatments as hereinafter described, that deeply imbedded stains are effectively removed. Many fabrics which have been soiled so badly and which could not be cleaned by conventional laundering have been restored to normal service as a result of the application of successive treatments in accordance with my invention. Generally about three cycles of my process are required to restore a badly soiled garment. An unexpected benefit of my treatment is that the textile fabric so treated has a distinctly improved hand, size and texture, rendering them easier to finish and more aesthetically appealing.

The essence of my invention is the discovery that acrylic resins of the types hereinafter disclosed may be applied to textile fabrics as a part of a final stage of a laundering operation whereby there is achieved a very low level of resin impregnation in the fabric. The impregnation of the acrylic resins on the textile fabrics is on the order of 0.005 to 0.05% by weight on a dry basis. A preferred amount is 0.01 to 0.2% by weight. It was an unexpected discovery to learn that this low level of resin impregnation would assist in the removal of deeply imbedded stains and give a textile fabric the ability to resist subsequently acquired stains. It was also unexpected to discover that repeated treatments of the fabrics with a low level of acrylic resin impregnation would give fabrics a soil release capability and desirable finish which, although only temporary, is equivalent in performance to the much more expensive process whereby the soil release resins are permanently attached to textiles by chemical means in the textile manufacturing process.

RESINS The resins suitable for practicing this invention are all derived from homopolymers and copolymers of acrylic acid and methacrylic acid.

The homopolymers which form suitable soil release resins are polyacrylic acid and polymethacrylic acid. Either homopolymer or mixtures of the homopolymers provide satisfactory soil release resins for textile fabrics in my process.

In addition to the homopolymers described above, various copolymers formed by copolymerizing acrylic or methacrylic acid with alkyl esters of acrylic acid or methacrylic acid are satisfactory soil release resins. In these copolymers the mole ratio of acrylic acid or methacrylic acid to the alkyl esters of acrylic acid or methacrylic acid must be at least 1 to 1 in order to provide water solubility or water dispersibility of the copolymer. Any ratio of acid to ester greater than 1 to 1 including the acid homopolymers provide suitable soil release resins. The alkyl substituents are C through C groups. Mixtures of these copolymers are also satisfactory temporary soil release resins.

Esters suitable for copolymerizing with acrylic acid or methacrylic acid to provide satisfactory temporary soil release resins are methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate and isobutyl methacrylate.

In addition to the copolymers described above which are useful temporary soil release resins, mixtures of the homopolymers with the various copolymers described above are particularly useful as temporary soil release resins.

Any ratio of mixtures of the homopolymers or mixtures of homopolymers and copolymers described above provides suitable temporary soil release resins for practicing my invention.

A preferred temporary soil release system comprises mixtures of the homopolymer of acrylic acid and copolymer formed from ethyl acrylate and methacrylic acid.

The above homopolymers and copolymers and their mixtures described above which provide satisfactory temporary soil release resins for fabrics in my new laundering process and compositions are hereinafter referred to in the specification and claims as acrylic resins.

The resin homopolymers and copolymers are conveniently added to the laundry machine in the form of water solutions, emulsions or dispersions. For example, polyacrylic acid is commercially available as 25 percent by weight aqueous solution. The acrylic resins are usually added directly to the souring solution in the laundry machine although the resin could be added to any reserve supply of souring solution.

SOURING SOLUTION The souring solutions are acid solutions generally made from one of the fluosilicates such as sodium fluosilicate. The concentration of the resin in the souring solution is not critical. However, there must be present sufi icient resin in the souring solution so that when the garment is dried there will remain on the fabric sufiicient soil release resin to provide a means for removing soil and stains. Such a concentration of resin in the souring solution is known as an effective amount. Generally, the concentration of resin in the souring solution will be at 1 part of resin by weight per 5,000 parts of souring solution. Good results have been obtained at /2 part resin per 5,000 parts of souring solution, while some improvement in soil release properties has been obtained at A part of resin per 5,000 parts of souring solution.

Higher resin concentrations are generally not needed for garments receiving regular resin treatments. However, higher concentrations may be used for reclamation treatment of severely soiled garments. In this special treatment resin concentration in the sour may reach 3.0 parts of resin per 5,000 parts by weight of souring solution.

If resin impregnation of the fabric is performed separately from the sour operation, either combined with some other fabric finishing operation or carried out independently, the concentration and pH of the resin in the separate treating solution must be the same as in the souring solution.

The souring operation in a commercial laundry is generally the last operation in the laundry process. For economic reasons, the application of the soil release resin is combined with the souring operation in order to avoid a separate laundry operation. However, if for some reason it is not desired to combine the sour and soil release impregnation treatment, they can be performed separately provided the resin treatment is the last operation in the laundry process. The resin impregnaion must be the last operation to prevent loss of the resins by any subsequent laundering involving immersion in or rinsing of the fabrics with water which would wash away most of the resin.

The sour operation removes the alkalinity in the fabrics which is not removed by the water rinses. Generally from two to five water rinses are employed prior to souring. The first water rinse is usually at the wash temperature of 180 to 190 F. Subsequent rinses are at progressively lower temperatures down to room temperature. Failure to remove nearly all of the alkali can cause skin irritation from the fabric.

The sour solutions are prepared from acid salts and other acidic materials. The silicofiuorides are the most common sours. The silicofluorides are obtained in the form of ammonium, sodium, magnesium or zinc fluosilicates. Other materials used in laundry sours are sodium and ammonium acid fluoride, ammonium ch oride and acetic acid. Liquid sources of sours are hydrofluoric acid and fiuosilicic acid.

The souring operation is generally done within a pH range of 4 to 6.5 and the amount of sour added will depend on the residual alkalinity from the washing cycle, the alkalinity of the water being used and the desired pH. Generally from 1 oz. to 12 ozs. of sour are used per 100 lbs. of dry textile fabrics. Generally from 350 to 500 pounds of water are used in each laundry operation for each 100 pounds of dry fabrics.

The combined souring operation and application of the acrylic soil release resin to the fabrics is undertaken at a temperature within the range of 70 to 180 F. Preferably, the temperature will be within the range of 95 F. and 180 F.

In combining the application of the sour and soil release resin to the fabrics, means must be taken to secure uniform mixing and suspension of the resin. The normal rotation of the laundry wheel is satisfactory for this purpose.

One or more of the following fabric finishing chemicals may be combined with the souring and resin application to the fabrics: Blueing is generally applied to white goods at the rate of oz. per 100 pounds of white goods; Fabric brighteners are applied at the rate of 1 oz. per 100 pounds of dry fabrics; Fabric softeners are applied to the sour solutions at the rate of 1 /2 to 2 ozs. per 100 pounds of dry fabrics.

Sizing is also compatible with the laundry souring solution and soil release resin. Sizing is generally wheat or corn starch and is used at a concentration of from 8 oz. to 1 lb. per 100 pounds of fabrics. Starch is applied to the souring at the same concentration. The above concentrations will provide an effective amount of fabric finishing agent. It will be appreciated that the concentration of fabric finishing agents in the souring solution are well known in the art. These concentrations will vary depend ing on local water conditions and the effect desired by the individual laundry operation.

DRYING The souring operation combined with resin impregnation and/or other fabric finishing treatment takes place within about 3 to minutes, preferably within 5 to 8 minutes. Following the treatment period in souring solution containing the acrylic resin the textile fabrics are separated from the treating solution and are then dried. Separation of the resin-sour solution is usually accomplished by centrifugal extraction or by hydraulic pressing.

There is generally retained on the fabric after separation of the souring solution or other fabric finishing solution about an equal weight of the treating solution. For every 100 pounds of dry clothes treated there will be about 100 pounds of sour solution. When the resin concentration in the sour is 1 part resin per 5,000 parts by weight of souring solution, then 100 pounds of clothes will have retained of a pound of resin or 0.02% resin. When the resin concentration in the souring solution is A: part resin to 5,000 parts by weight of souring solution, the resin retention on the fabrics is about 0.005% by weight. At /2 part resin per 5,000 parts by weight of souring solution, the resin impregnation on the fabrics after drying will be about 0.01% by weight. At 2 /2 parts resin per 5,000 parts of souring solution the resin impregnation on the fabrics will be about 0.05%, by weight. A preferred impregnation on the dry fabrics is about 0.01 to 0.02% by weight.

The wet resin impregnated fabrics are dried at temperatures varying from room temperature to about 350 F. Drying is accomplished in conventional air dryers for clothes or by ironing or by pressing. Ironing temperatures are generally about 350 F. Somewhat lower temperatures are generally used in the air dryers and satisfactory drying can be accomplished with air temperatures as low as about 70 F. or room temperature. The water is more rapidly removed at higher temperatures and temperatures of 150 to 350 F. are preferred.

The best mode of practicing my invention may be understood from a consideration of the following examples:

Example 1 In a Milnor Washer, Model #600CWM5 of 35 pounds dry clothes capacity was placed 24 pounds of cotton rags and 1 pound of 10" square test swatches of white shirting, 65/35 polyester cotton finished with a durable press resin. The washer was filled with water to the 16 gal. level and 0.25 pounds of a commercial all-inone laundry detergent was added. The water temperature was 150 F. After 10 minutes of agitation, the system was drained, refilled, and 0.125 pounds of detergent was added. It was agitated 5 minutes; at 150 F. and then drained. There were four 30 gal. water rinses, one each at 150 F., 130 F., F., and 90 F. After the four rinses, water was added to the 16 gal. level at F., the pH adjusted to 4.5 by adding sodium fluosilicate laundry sour, and the system was agitated for one minute. At this time there was added one pint of an aqueous resin solution containing 3.9% by weight of a 25% by weight polyacrylic acid solution and 9.6% by weight of a 20% by weight solution of a copolymer of ethyl acrylate and methacrylic acid in the ratio of 2.7 mols methacrylic acid to 1 mol of ethyl acrylate. The one pint of resin solution provides 4.4 grams of polyacrylic acid and 8.7 grams of the copolymer. The system was agitated for 8 more minutes, drained, and centrifugely extracted for 1 minute. The cotton rags and test swatches were then dried by ironing for 15 seconds at 350 F.

The test swatches were soiled by placing on them at two separate spots, 5 drops of refined mineral oil and 5 drops of used motor oil. These spots were then blotted and allowed to age for a minium of one half hour. The staining and rating procedure was the standard method of the American Association of Textile Chemists and Colorists, Test -l969.

Control swatches made from fabric identical to the test swatches were laundered in exactly the same manner as the foregoing procedure with the exception that no polymer and copolymer mixture was added to the souring step.

The control and the test swatches were then subjected to three additional cycles of laundering, treatment with polymer and copolymer solution, drying, and staining, the subsequent stains being placed at different locations on the test swatches. The test series was carried out with resin addition in each souring step, and the control series was carried out with no resin addition at any time.

Following each ironing, the color intensity of the spot was evaluated. Rating of 5 represents complete disappearance of spot.

After the first laundering following treatment with resin and staining, the stains on the treated fabric were seen to be slightly lighter than the stains on the untreated fabric. That is, the laundering stage following resin treatment was more effective in removing the stains. After four complete cycles the stains applied at the end of the first cycle were nearly completely gone in the case of the test fabrics treated with resin and were still distinctly visible in the case of the untreated control fabric.

Example 2 In a Milnor Washer, Model #600-CWM-5 of 35 pounds capacity was placed 24 pounds of cotton rags and 1 pound of square swatches of white shirting, 65/35 polyester cotton finished with a durable press resin. The washer was filled with water to the appropriate level and 0.25 pounds of a commercial all-in-one laundry detergent was added. The water temperature was 150 F. After 10 minutes of agitation, the system was drained, refilled, and 0.125 pounds of detergent was added. It was agitated 5 minutes at 150 F. and then drained. There were four high level rinses, one each at 150 F., 130 F., 110 F., and 90 F. The water was raised to the low level (16 gal.) at 120 F. Three pints of the aqueous resin solution of Example 1 were added to the water. The resultant pH was 6.1. The system was agitated for 5 minutes, drained and centrifugely extracted for 1 minute. The cotton rags and test swatches were then air dried at 73 F. for 2 /2 hours.

The test swatches were soiled by placing on them at two separate spots, 5 drops of refined mineral oil and 5 drops of used motor oil. These spots were then blotted and allowed to age for a minimum of one half hour.

Control swatches were prepared in exactly the same manner except that no resin mixture was added in the last step. The results after one wash, then application of soil release resin, then staining, then one additional wash showed control values of 3.5+ and 2.5 for mineral oil and motor oil respectively, and test value of 3.5+ and 3.0 for the respective stains on the resin treated fabric.

Example 3 The test and control experiments of Example 1 were carried out varying the temperature of the solution in which the soil release polymer was applied to the textile. These experiments are recorded in Table II.

TABLE II 8 Example 4 The test and control experiments of Example 1 were carried out, except that the damp test swatches, after centrifugal extraction, were tumbled in a hot air dryer at 150 F. Following are the results after 4 cycles of resin impregnation treatments with comparative controls.

TABLE III Spots applied End of 1st End of 2d End of 3d cycle cycle cycle Mineral Motor Mineral Motor Mineral Motor oil oil oil oil oil oil Test swatches- 4. 5+ 4. 5+ 4. 5+ 4. 0+ 4. 5 3. 5+ Control 4. 5 2. 5+ 4. 0+ 2. 5+ 4. 0+ 2. 5

Example 5 In a Milnor Washer, Model #600-CWM-5 of 35 pounds capacity was placed 24 pounds of cotton rags and 1 pound of 10" square swatches of white shirting, /35 polyester cotton finished with a durable press resin. The washer was filled with water to the appropriate level and 0.25 pounds of a commercial all-in-one laundry detergent was added. The water temperature was 150 F. After 10 minutes of agitation, the system was drained, refilled, and 0.125 pound of detergent was added. It was agitated 5 minutes at 150 F. and then drained. There were four high level rinses, one each at 150 F., 130 F., 110 F., and 90 P. Then water was raised to the low level (16 gal.) at 120 F. The pH was adjusted to 4.1 by addition of ammonium fluosilicate sour and then 5 oz. of wheat starch were added to the souring solution. After one minute of agitation, there was added 1 pint of the resin solution described in Example 1. The system was agitated 8 more minutes, then centrifugely extracted for 1 minute. The textile fabrics were then tumble dried in a hot air drier at 200 F. air temperature.

The test swatches were soiled by placing on them at two separate spots, 5 drops of refined mineral oil and 5 drops of used motor oil. These spots were then blotted and allowed to age for a minimum of one-half hour.

Control swatches were prepared in exactly the same manner as the foregoing procedure with the exception that no polymer and copolymer mixture was added to the souring step.

The control and the test swatches were then subjected to three additional cycles of laundering, treatment with polymer and copolymer solution, drying, and staining, the subsequent stains being placed at different locations on the test swatches. The test series was carried out with polymer addition in each souring step, and the control [Grading at the completion of four cycles of spots applied at the end 01 1st cycle then subjected to three full cycles of treatment] Temperature of souring and application solution F. F. F. F. F. F.

Min. Mot. Min. Mot. Min. Mot. Min. Mot. Min. Mot. Min. Mot. oil oil oil oil oil oil oil oil oil oil oil oil Test swatches 5. 0 3. 0+ 4. 5+ 3. 0+ 4. 5+ 5.0 4. 5+ 5. 0 4.0 5. 0 4. 0 Control 3. 5+ 3. 0 4. O 2. 5+ 3. 0 4. 5+ 3. 0+ 4. 5+ 3. 0 4. 5+ 3. 0

It is seen that even at an application solution temperature as low as 70 F. there is a small effect of the polymer treatment. More pronounced effect is Obtained at 95 F. and higher.

series was carried out with no polymer addition at any time.

The results after 4 cycles of treatment are given in Table IV.

TABLE IV solution of polyacrylic acid, and 9.6% by weight based 8 t l, d on the solution of a 20% by weight solution of a copolyp S app mer (27 mole percent ethyl acrylate, and 73 mole percent End of 151; End (1)f2d End (if3d methacrylic acid), was packaged with fluorocarbon pro- GW 8 We e We a pellent in a pressure container. This mixture was sprayed Mimi 1X1 Motor} Minerall Motoirl Minegal Motg r onto clean dry crease-resistant, 65/35 polyester textile 01 01 01 0 until the textile was slightly damp to the touch. The wet 5.0 3. 0+ 5.0 3. 0+ 5.0 weight increase was approximately 3% of the dry weight, equivalent to a polymer add-on of about 0.09% of the E l 6 10 dry textile. The textile swatch was subsequently dried by The experiment of Example 1 was carried out in which ggg i :2 3 2 t i fg g m g f $2 g varying amounts of sodium fluosilicate souring agent h an ere a were used to achieve various pH of the system in which si wflth a conventlonal home launqry the soil release polymers were applied to the textile. The eteggent i d A i removal .from the washuig results are tabulated in Table v. 15 mac me t e amp swatc as were dried, sprayed aga n TABLE V [Grading at the completion of the second cycle of spfotts atpplieg] at end of 1st cycle then Subjected to one full eye 6 0 I88 men pH of application solution Min. Mot. Min. Mot. Min. Mot. Min Mot, Min. Mot. Min. Mot.

oil oil oil oil oil oil 011 Oil 011 oil oil oil The procedure of Example 1 was carried out with a variety of textiles. These included 65/35 polyester cotton with crease resistant finish, rayon, pure cotton, silk, nylon,

with the polymer solution, then redried at ambient temperature. After .4 cycles of treatment, the swatches sprayed with polymer solution showed a motor oil stain rating of 3.5+ compared with 3.0+ for the control, and a mineral oil stain rating of 5.0 compared with 3.0+ for the control.

Example 9 The procedure of Example 1 was carried out in which the ratio of the mixture of polymer solutions added to the souring solution was varied. The results of the experiments are reported in Table VI. Percentages are by weight.

TABLE VI [Grading at the completion of three cycles of spots applied at end of 1st cycle, then subjected to two full cycles of treatment] 6.5% of a 25% 3.9% of a 25% solution of polysolution of polyacrylic acid in acrylic acid in 13.5% of a 25% water together water together solution of po lywith 6.5% of a with 9.6% of a 13.5 of a 20% acrylic acid in 20% copolymer 20% copolymer copolymer 1 solution water solution in water solution in water in water Min. oil Mot. oil Min. oil Mot. oil Min. oil Mot. oil Min. oil Mot. oil

Test swatches- 4. 0+ 3. 0 4. 0+ 3. 0+ 4. 5+ 4.0 4.0 3. 0+ Control 4. 0 2. 5+ 4. 0+ 2. 5 4. 0+ 3. 0 4. 0 2. 0+

1 Copolymer oi ethylacrylate and methacrylic acid in mole ratio of l to 2.7.

' Example 8 An aqueous solution containing approximatel 3.9% by weight based on the solution of a 25% by weight aqueous It is observed that improved stain removal versus the control is obtained at all ratios.

Example 10 The procedure of Example 1 was carried out except that the amount of soil release polymer added to the souring solution was varied. Results are reported in Table VII.

TABLE VII [Grading at the completion of four cycles of spots applied at the end of 1st cycle, then subjected to three full cycles of treatment] Amount. of polymer solution added pt./25 lbs. textile Min. oil Mot. oil Min. oil Mot. oil Min. oil Mot. oil Min. oil Mot. oil

Test swatches. Control It is seen that slight results are obtained when as little as A1 pint of polymer solution is added per 25 pound load. Good improvement is obtained at /2 pint per 25 pounds and optimum results are obtained with 1 or more pints per 25 pound load.

acrylic acid in the mole ratio of 1 to 2.7 in water was added and the system agitated for eight additional minutes. The washer was then drained and the garments extracted in a hydraulic extractor. The garments were eventually tumbled dry in a hot air dryer at 180 F.

5 Exam 1e 11 For purposes of this test, garments from an automotive p repair shop were washed in the manner described and The experiment and procedure of Example 1 is repeated then returned to service on a two week cycle basis. After in which the ratio of ethyl acrylate to methacrylic acid in six months, that is 12 washing treatments and use cycles, the copolymer is varied. In general good results are obthe garments were seen to have only a few light residual tained if the copolymer contains more than about 1 mole of stains, and were considered top quality in terms of overmethacrylic acid per mole of ethyl acrylate since the coall appearance. polymer will be water soluble or dispersible. Conversely, Control experiments were simultaneously conducted if the copolymer contains less than about 1 mole of with identical garments used in automotive repair which methacrylic acid per mole of ethyl acrylate the copoly- 15 were subjected to exactly the same laundering cycles with mer will be essentially insoluble and will therefore be inthe exception that polymer solution was not added to effective in the practice of this invention. Compositions the souring solutions. At the end of six months of service up to and including pure polymethacrylic acid will perthese garments were generally dingy in appearance and form well. contained numerous dark grease stains. Approximately Example 12 20% 0f the garments were considered aesthetically unacceptable and had to be scrapped. The experiment of Example 1 was carried out, except that cotton and 65/35 unfinished polyester/cotton were Example 14 used as fabrics, and a commercially available sizing con- The unacceptable heavily soiled garments left from the taimng starch was added at the rate of 4 ounces per 25 control part of Example 13 were laundered in exactly pounds of textlle to the souring solution together with the the same manner as in Example 13 except that 12 quarts polymer solution. of polymer solution containing 3.9% by weight of a 25% TABLE VIII Spot applied end of 1st cycle observed end Spot applied end of 1st and 2d Spot applied end 011st, 2d and 3d cycles of 2d cycle cycle observed end of 3d cycle observed end of 4th cycle Mineral Motor oil oil Mineral oil Motor oil Mineral 00 Motor oil Spot number 1 1 1 2 1 2 1 2 3 1 2 3 Cotton (test) 4.5+ 3.0 5.0 4.5 4.0+ 3.0+ 5.0 5.0 4.5 4.5+ 4.0 3.5 Cotton (control 4. 0+ 3.0 4.5+ 4.5 3.5+ 3.0+ 5.0 4.5+ 4.5+ 4.0 3. 5+ 3.5 Unfinished poly.cott0n (test) 4.5 3.0+ 5.0 4.5 3.5+ 3.5+ 5.0 5.0 4.0+ 4.0 4.0 3.5 Unfinished poly.c0tton (cotton) 4.0+ 2.5 4. 0+ 4.0 3.0 2.5 4.5+ 4.5 4.0 3.0 2.5+ 2.5

Example 13 by weight aqueous solution of polyacrylic acid together Blue industrial work uniforms from an automotive repair shop, both shirts and pants, were loaded into a stainless steel washer 42" in diameter by 84" long. This washer was loaded with 200 pounds of permanent press finished 65/35 polyester content blend garments. Hot water was added to the washer to the level of 6 (170 gallons) at a temperature of 190 F. The garments were agitated by rotation of the washer for 6 minutes to remove loose grease and soil, and the water was removed from the washer.

For the next step, water was added to the washer to the same level at 190 F., and 6 pounds of alkaline all-inone laundry detergent was added. There was also added 3 pints of emulsifiable kerosene to improve detergency. After 20 minutes of agitation, the washer was emptied. The washer was filled again to the same level with water at the same temperature, and the clothes were agitated without the addition of supplies and then subsequently drained. The washer was filled again to the same level and temperature. Three pounds of the alkaline detergent and 1 /2 pints of emulsifiable kerosene was added and the system was agitated for 15 minutes.

After draining this system there followed 5 rinse stages. In each of these stages, water was added to 12" level (262 gallons), then dumped after 2 minutes of agitation. The temperature in each of these 5 rinses was lowered in uniform steps from the original 190 F. to a final rinse at 120 F.

For the final operation, water was drawn into the washer at the 6" level at 120 F. Six ounces of sodium silicofluoride sour and 36 ounces of starch-based sizing agent were added and allowed to distribute through a 2 minute agitation. Then 6 quarts of polymer solution containing 3.9% by weight of a 25% by weight aqueous solution of polyacrylic acid together with 9.6% weight of a 20% weight copolymer of ethyl acrylate and methwith 9.6% weight of a 20% weight copolymer of ethyl acrylate and methacrylic acid in the mole ratio of 1 to 2.7 in water were added in the souring solutions. After two subsequent launderings and polymer treatment there was seen to be a distinctly measurable improvement in appearance. After 4 cycles of treatment with polymer followed by laundering (without intervening use), most of these garments were so free of stains and generally improved in appearance that they were returned to regular service. There was still further improvement in appearance upon as many as six cycles of polymer treatment and laundering, but little further improvement with more cycles of treatment than that.

Example 15 The following copolymer compositions can be prepared by standard aqueous polymerization technique:

Mole ratio Ester Acid acid/ester Butyl acrylate Methacrylic acid 6. 0/1 Methyl acrylate Acrylic acid 2. 5/1 Isopropyl acrylate Methacrylic acid 1. 5/1 Butyl acrylate Acrylic acid 9.0/1 Ethyl methaerylate. o 15. 0/1 Butyl methacrylate Methacrylic a 6. 0/1 Methyl methacrylate Acrylic acid 3. 0/1

These copolymers are useful as temporary soil release resins in the practice of my invention.

Example 16 The comparative test and control swatches are shown in Table IX.

1. In a process for laundering textile fabrics in which the fabrics are washed in aqueous alkaline detergent, rinsed with water to remove soil and the major portion of the alkaline detergent, then contacted with a laundry souring solution to remove residual alkalinity and finally dried, the improvement to impart temporary soil release to the textile fabrics comprising contacting the textile fabrics in the final stage of the laundering process prior to drying with a laundry souring solution having a pH within the range of about 4 to about 6.5 and containing from A at about 3 parts by weight of resin per 5,000 parts b weight of souring solution of one or more acrylic resins selected from the group consisting of polyacrylic acid, polymethacrylic acid and copolymers of acrylic acid and methacrylic acid with alkyl esters of acrylic acid and methacrylic acid, said alkyl substituents having one to four carbon atoms and said copolymers having a mole ratio of acid to ester of at least 1 to 1.

2. The process according to claim 1 in which the souring solution contains an effective amount of one or more fabric finishing chemicals selected from the group consisting of blueing, sizing, brightener and softener in addition to the acrylic resin.

3. The process according to claim 1 in which the souring solution contains an effective amount of a laundry sizing agent in addition to the acrylic resin.

4. The process according to claim 1 in which the souring solution contains an effective amount of a fabric softener in addition to the acrylic resin.

5. The process according to claim 1 in which the acrylic resin consists essentially of polyacrylic acid in admixture with a coplymer of methacrylic acid and ethylacrylate said copolymer having a mole ratio of methacrylic acid to ethylacrylate of at least 1 to 1.

6. The process of claim 1 in which the laundry souring solution is prepared by adding to water an effective amount of one or more compounds selected from the group consisting of ammonium fluosilicate, magnesium fiuosilicate, sodium fluosilicate, zinc fluosilicate, sodium bifluoride, ammonium bifiuoride, ammonium chloride, acetic acid, fluosilic acid and hydrofluoric acid.

7. Ina process for laundering textile fabrics in which the fabrics are washed in aqueous alkaline detergent, rinsed with water to remove soil and substantially all of the alkaline detergent, contacted with a laundry scouring solution to remove residual alkalinity and thereafter contacted with an aqueous solution of a fabric finishing chemical and finally dried, the improvement to impart temporary soil release to the textile fabrics comprising contacting the textile fabrics in the final stage of the laundering process prior to drying with an aqueous solution of one or more fabric finishing chemicals selected from the group consisting of blueing, sizing, brightener and softener at a pH within the range of about 4 to about 6.5 and containing from A to about 3 parts by weight of resin per 5,000 parts by weight of solution of fabric finishing chemical of one or more acrylic resins selected from the group consisting of poly: acrylic acid, polymethacrylic acid and copolymers of acrylic acid and methacrylic acid with alkyl esters of acrylic acid and methacrylic acid said alkyl substituents having one to four carbon atoms and said copolymers having a mole ratio of acid to ester of at least 1 to l.

8. The process of claim 1 in which the souring solution is maintained within the range of to F.

9. The process of laundering textile fabrics in which the fabrics are given three or more successive treatments in accordance with the process of claim 1.

10. The process according to claim 1 in which the souring solution contains an effective amount of a fabric brightener in addition to the acrylic resin.

11. In a process for laundering textile fabrics in which the fabrics are washed, rinsed with Water to remove soil and finally dried, the improvement to impart temporary soil release to the textile fabrics comprising contacting the rinsed textile fabrics immediately prior to drying with an aqueous solution containing from A to about 3 parts by weight of resin per 5,000 parts by weight of solution of an acrylic resin selected from the group consisting of polyacrylic acid, polymethacrylic acid and copolymers of acrylic acid and methacrylic acid with alkyl esters of acrylic acid and methacrylic acid said alkyl substituents hav-.

ing one to four carbon atoms and said copolymers having a mole ratio of acid to ester of at least 1 to 1 and at a pH of about 4.0 to about 6.5.

12. The process of claim 11 in which the aqueous solution of the acrylic resin is maintained between 70 F. and 180 F.

References Cited UNITED STATES PATENTS 2,241,580 5/1941 Bishop 8-137 2,805,208 9/1957 Touey et a1 252-DIG. 2 3,284,364 11/1966 Siegele 252DIG. 15 3,567,498 3/1971 Rafferty 117--139.5A

MAYER WEINBLATT, Primary Examiner US. Cl. X.R'..

117139.5 A, 139.5 CQ; 252Dig. 2, Dig. 12; 260-29.6

UNITED sums PA'IENT OFFICE CERTIFICATE OF CORRECTION s new; we. 3, 782, 898 and January 1, 1974 Investor) Ha r creston Mandll, Ir.

It is certified that error appears in cm abovc-idcotified patent dad that said Latter. Pam: an hcroby correct I; ohowu'below:

Solemn 2, line 7, 0. O1 to 0.2% should read O. 01to 0. 02%".

' Column 10, TABLE VI, fourth column-line 5, 13. 5 should read "13. 5%".

TABLE VIII, firstool u'm'n, line 3 under-heading, olose parienj zhesisafter "controf? line five cotton should read (control) '1.

Column 13, TABLE IX, 11ne3, under'heading; second col umn End ofl st read 5- "End of 1st ycle"-.. l

I Column 13, llneZZ ot should read -"to"'--.

Signed and sealed this 11th day of June 1971;.

(SEAL) Attest: i V EDWARD MJLETCHERJR. cfmRsHALL DANN Att'eating Officer I Commissioner of Patents roan p o-10w (to-9)