US 3912681 A
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United States Patent [191 Dickson COMPOSITION FOR IMPARTING NON-PERMANENT SOIL-RELEASE CHARACTERISTICS COMPRISING AN AQUEOUS ACIDIC SOLUTION OF POLYCARBOXYLATE POLYIVIER  Inventor: Robert E. Dickson, Belle Mead, NJ.
 Assignee: Colgate-Palmolive Company, New
[ Notice: The portion of the term of this patent subsequent to Aug. 20, 1991, has been disclaimed.
 Filed: Nov. 12, 1973  Appl. No.: 414,880
Related US. Application Data  Continuation-impart of Ser. No. 249,089, May 1,
 US. Cl. 260/29.6 H; 8/1 15.6; 8/137; 252/DIG. 2; 260/l7.4 CL; 260/29.6 WB;
 Int. Cl. D06M 15/14 [4 1 *Oct. 14, 1975  Field of Search 260/29.6 WB, 29.6 H
[5 6] References Cited UNITED STATES PATENTS l/1974 Mandell 260/29.6 WB
Primary Examiner-Howard E. Schain Assistant Examiner-Peter Kulkosky Attorney, Agent, or Firm-Steven J. Baron; Norman Blumenkoph; Herbert S. 7 Sylvester  ABSTRACT 23 Claims, No Drawings COMPOSITION FOR IMPARTING NON-PERMANENT SOIL-RELEASE CHARACTERISTICS COMPRISING AN AQUEOUS ACIDIC SOLUTION OF POLYCARBOXYLATE POLYMER This application is a continuation-in-part of my copending application, Ser. No. 249,089, filed on May 1, 1972 the benefit of which filing date is claimed.
BACKGROUND OF THE INVENTION This invention relates to a composition which can be conveniently used in the rinse cycle of a home laundry procedure for treating a textile substrate to impart a soil-release characteristic thereto.
The genesis of synthetically produced textile fibers has brought about a tremendous effort in the textile industry along numerous avenues. There has been much research effort directed to the improvement of these synthetic fibers per se, and improved blends of synthetically produced fibers with natural fibers, i.e., cellulose fibers or keratinous fibers. Results of this research have been successful, and the direction of research has been directed from the synthetic polymer per se and/or blends of said polymers with other naturally occurring fibers, and, more specifically, to the physical characteristics and/r endurance properties of garments pr0- duced from synthetic fabrics and/or fabric produced from blends of synthetic fibers and naturally occurring fibers.
Much research has been directed to the attainment of a garment having improved soil-release properties. Many of the synthetically produced fibers that are presently being incorporated in blends with naturally occurring fibers have a propensity to accept and retain oily grime and dirt. Accordingly, when the garment is being worn the soil and/or oily materials accumulate on the garment and settle in the fabric. Once the garment becomes soiled, it is then subjected to a cleaning process for removal of the dirt and/or oily deposits, and only a dry cleaning process will successfully clean the garment.
The cleaning process normally employed, however, is washing in a conventional home washing machine by the housewife. During a wash cycle, it is virtually impossible to remove the soil and/or oily stains from the garment, and secondly, assuming that the undesirable materials are removed from the garment or a fairly clean garment is being washed, soil remaining in the wash water is redeposited onto the garment prior to the end of the wash cycle. Hence, when the garment is removed from the washing machine and subsequently dried, it has not been properly cleaned. Such a condition, heretofore unavoidable, is quite disadvantageous in that the garment after being worn never again assumes a truly clean appearance, but instead tends to gray and/or yellow due to the soil and/or oily materials deposited and remaining thereon. Further use and washing of the garment increases the intensity of graying to the point that ultimately the garment is unacceptable for further wear due to its discoloration. The pro cess of the present invention solves the soiling problem as hereinafter described.
The problem heretofore confronted with fabrics having synthetic fibers incorporated therein, or made entirely of synthetic fibers, has been that the synthetic fibers, as well as being hydrophobic, are oleophilic. Therefore, while the oleophilic characteristics of the fiber permit oil and grime to be readily embedded therein, the hydrophobic properties of the fiber prevent Water from entering the fiber to remove contaminants therefrom.
Attempts have been made to reduce the oleophilic characteristics of these synthetic fibers by coating the fibers with a coating that is oleophobic, i.e., will hinder the attachment of soil or oily materials to the fibers. Many polymer systems have been proposed which are capable of forming a film around the fibers that constitute the textile material, particularly acid emulsion polymers prepared from organic acids having reactive points of unsaturation. These treating polymers are known as soil-release agents.
The term soil-release" in accordance with the present invention refers to the ability of the fabric to be washed or otherwise treated to remove soil and/or oily materials that have come into contact with the fabric. The present invention does not wholly prevent the attachment of soil or oily materials to the fabric, but hinders such attachment and renders the heretofore uncleanable fabric now susceptible to a successful cleaning operation. While the theory of operation is still somewhat of a mystery. soiled, treated fabric when immersed in detergent-containing wash water experiences an agglomeration of oil at the surface. These globules of oil are then removed from the fabric and rise to the surface of the wash water. This phenomenon takes place in the home washer during continued agitation, but the same effect has been observed even under static conditions. In other words, a strip of polyester/cotton fabric treated with a dilute solution of the composition of the present invention and soiled with crude oil, when simply immersed in a detergent solution will lose the oil even without agitation.
Concentrated solutions of soil-release polymers have been padded onto fabrics by textile manufacturers to impart a permanent soil-release finish to the fabric. As the amount of soil-release polymer on the fabric is increased, the ability of the fabric to release soil is increased. However, fabrics with this permanent soilrelease finish possess many disadvantages. As the amount of soil-release polymer on the fabric is increased the fabric has a tendency to become stiffer and lose the desirable hand characteristic of the fabric. Thus, the upper limit on the amount of soil-release polymer to be used is determined by economics and the resulting adverse effect on the fabric. Fabrics with a heavy application of soil-release polymer do not have the same desirable appearance and hand as the same fabrics without the soil-release coating. Furthermore,
practically speaking, there is a set range of soil-release agent that can be applied, dictated by commercial success.
Some soil-release polymers are effective fabric treating agents even at very low levels on the fabric, at which levels the appearance and hand of the fabric are not adversely affected. Thus, an ideal method of treating a synthetic fiber containing fabric would be to reapply a very small amount of soil release polymer to the fabric each time the fabric is washed.
Certain polycarboxylate polymers, such as partially hydrolyzed acrylamide polymers and certain copolymers of methacrylic acid with ethyl acrylate, are very effective soil-release agents at low levels on the fabric. However, these polymers cannot be deposited onto fabrics from dilute solution, as the polymers are so soluble in water that they will not deposit onto the fabric from dilute solution.
SUMMARY OF THE INVENTION It has now been discovered that a very effective nonpermanent soil-release finish can be applied to fabrics using a dilute aqueous solution of a polycarboxylate polymer if the pH of the solution is lowered to about 3, most conveniently with a mineral acid, such as, sulfuric acid. Lowering the pH of the solution to this level decreases the solubility of the polymer sufficiently to cause the soil-release polymer to deposit onto the fabric. A dilute solution of the soil-release polymer and sufficient acid to lower the pH of the treating water to about 3, could easily be made up in the rinse cycle of a typical home laundry process.
Polycarboxylate polymers found to be effective soilrelease agents when applied from dilute solution at a pH of about 3 are those polycarboxylate polymers having an acid equivalent weight (i.e., gram per mole of carboxylate) in the range of from about 100 to 175. The preferred acid equivalent weight for these polymers for use in the present invention is about 110 to about 135.
The most effective polymers for use in the instant invention are copolymers of an ethylenically unsaturated monocarboxylic acid and a lower alkyl (C acrylate or methacrylate. The acid component of the copolymer may be derived from acrylic, methacrylic, ethacrylic, crotonic or the like. The acrylate or methacrylate may be comprised of up to 8 carbon atoms such as methyl,
ethyl, propyl, butyl and the like. The ester portion may furthermore be substituted such as by hydroxy or perhalo groups or both, namely, the dihydroperfluorooctyl moiety.
Preferred are the copolymers of methacrylic acid with ethyl acrylate or methacrylate and copolymers of acrylic acid with dihydroperfluoro-octyl methacrylate. The relative weight ratios of the two monomeric components can vary from about 50% acid to about 50% acrylate or methacrylate to about 25% acid to about 75% acrylate or methacrylate; a ratio of about 60 to 70% to about 40 to 30% acrylate or methacrylate is preferred, optimally about %:%a relative proportion.
Most preferred soil-release polymers for use in the present invention are about 30% hydrolyzed polyacrylamide or a copolymer of a methacrylic acid with ethyl acrylate made from about /3 methacrylic acid and about /3 ethyl acrylate. Polymers of molecular weights ranging from about 2,000 to about 5 million have been found to be effective; although polymers having a molecular weight of about 5,00,000 and to about 1 million are preferred.
The pH of the treating composition is preferably lowered with sulfuric acid, although other mineral acids such as hydrochloric acid, phosphoric and nitric acid could also be used to adjust the pH. The acid can be employed either in the concentrated form or as a dilute acid. Generally speaking, the acid will be employed in amounts sufficient to lower the pH of the water to about 3. It is to be understood that the foregoing will naturally be dictated by the concentration of the acid and the initial pH of the water (laundry water is generally about 7-8) as well as the particular copolymer employed.
The ratio of the acid to the copolymer will, however, generally be in the range of about 1.5:1 to about 2.0:1
where sulfuric acid is employed, the acid is preferably 4 molar.
The composition will generally be employed in amounts, such that the concentration thereof in the rinse water will be about 0.01 to about 1.0%, preferably about 0.03 to about 0.07.
It is, of course, to be understood that ordinarily the composition will be marketed and packaged as a concentrated liquid such that same need only be added to the rinse cycle, such as for instance, to the drum of a laundry machine. In the latter instance, the operator need only remove the composition from its container and add same to the rinse cycle, the subsequent dilution with water thereafter yielding a dilute aqueous solution of the same.
The polymers of the composition of the present invention form a hydrophilic film on the fibers upon dry ing, and afford soil releasability at that point. Each subsequent treatment serves to enhance the soil-release characteristics of the fabric substrate. Since the soilrelease finish can be applied with each laundering, the soil-release effect is not lost with repeated washings.
The soil-release properties of pure cellulosic fiber fabrics are much better than those of synthetic fiber containing fabrics, e.g., polyester fibers, in that the synthetic polyester fibers are hydrophobic and thus prevent the ingress of water that is necessary for cleaning the fabric, and also possess an electrical charge that attracts soil particles.
The compositions of the present invention may be used to treat a wide variety of textile materials made exclusively from synthetic polymer materials as well as blends of natural and synthetic fibers. Examples of synthetic fibers which may be successfully employed in the practice of the present invention include those made with polyamide, acrylic, and polyester fibers. Blends of natural and synthetic fibers which may be successfully treated with the compositions of the present invention include fabrics containing 50% polyester/50% cotton, 65% polyester/3 5% cotton, etc. Cellulose fibers such as viscose, regenerated cellulose, etc., also may be combined with cellulosic fibers. The compositions of the present invention are most effective on fabrics of pure polyester and blends of polyester and cotton with a permanent press finish.
DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE I A 0.05% solution of a copolymer of methacrylic acid and /3 ethyl acrylate, having a molecular weight of about one million, is made up and the pH of the solution adjusted to 3 with 4 molar sulfuric acid. Prewashed swatches of 65% polyester/35% cotton with a permanent press finish were soaked for 10 minutes in the treating solution and allowed to dry. A control swatch received no polymer treatment.
3 drops of 1:1 used motor oil/mineral oil were dropped into the center of each of the swatches, and the oil mixture was allowed to spread and set for three hours. The swatches were then washed in a solution of 1.5 g/liter of a 10-2-2 (anionic-nonionicsoap) commercially available household laundry detergent for 10 minutes at 80-90F., and rinsed for 5 minutes.
The final reflectance of the treated swatches was Rd units. The final reflectance of the control swatch was 50 Rd units.
EXAMPLE II Prewashed swatches of 65% polyester/35% cotton were soaked for minutes in an aqueous treating solution comprising 0.02% of a copolymer of /3 methacrylic acid and /3 ethyl acrylate, the copolymer having a molecular weight of about one million, and enough 4M sulfuric acid to adjust the pH of the solution to 3. This was the equivalent, in a home washing machine, of 0.9 cups per washer of an emulsion made from 161 grams of copolymer and 55 grams of 4 Molar sulfuric acid. The treated swatches were allowed to dry. A control swatch received no polymer treatment.
Three drops of 1:1 used motor oil/mineral oil were dropped into the center of the swatches, and the oil mixture was allowed to spread and set for 3 hours. The
- swatches were then washed in a solution of 1.5 g/liter of a 10-2-2 (anionic-nonionic soap) commercially available household laundry detergent for 10 minutes at 80-90F., and rinsed for 5 minutes.
The final reflectance of the treated swatches was 68 Rd units. The final reflectance of the untreated swatch was 50 Rd units.
EXAMPLE III A prewashed swatch of 65% polyester/35% cotton was soaked for 10 minutes in an aqueous treating solution comprising 0.015% of a copolymer of methacrylic acid and /3 methylacrylate, the copolymer having a molecular weight of about one million, and sufficient 4M sulfuric acid to adjust the pH of the solution to 3.0, and about 0.01% of very fine carbon black suspended in the solution. This swatch was labeled A. A similar prewashed swatch, labeled B, was soaked in an aqueous treating solution comprising 0.015% of a copolymer of methacrylic acid and /a methacrylate, the copolymer having a molecular weight of about one million, and about 0.01% of very fine carbon black suspended in the solution. This solution had a pH of 7.5. A third swatch, labeled C, was soaked for 10 minutes in water containing about 0.01% of very fine carbon black suspended therein. The swatches were allowed to dry in the air.
The swatches were then washed separately in a solution of 1.5 g/liter of a 10-2-2 commercially available household laundry detergent for 10 minutes at 8090F., and rinsed for 5 minutes. The reflectance of the swatches in Rd units was then measured. The changes in reflectance are shown in Table I.
TABLE I Reflectance Reflectance Changes in Swatch before wash, Rd after wash, Rd reflectance. Rd
A 30.1 69.1 39.0 B 63.4 72.3 8.9 C 32.5 47.7 15.2
The large difference in reflectance between A and C for reflectance after washing and for change in reflectance shows the ability of the polymer to act as a soilrelease agent.
The swatches may also be soiled by rubbing them on a plexiglas plate coated with Spanglers soil (skin soil) and allowed to age for 3 hours. The reflectance of the swatches in Rd units may then be measured.
EXAMPLE IV Identical dacron polyester swatches were treated by soaking in a tergotometer for 25 minutes in a 0.02% aqueous solution of a copolymer of methacrylic acid, ethylacrylate having a pH of 3 from the addition of 4 molar H SO These swatches were labeled A. Dacron polyester swatches, labeled B, were similarly soaked in a tergotometer in a 0.05% solution of the copolymer at a pH of 3. Dacron polyester swatches labeled C received no treatment.
The swatches were soiled with natural skin soil obtained by the Trowbridge Skin Soil Method, which involved having panelists rub their arms and foreheads with the swatches. The soiled swatches were then pressed with a warm iron to aid in working the soil into the fabric.
The swatches were then washed separately in a solution of 1.5 g/liter of a 10-2-2 commercially available household laundry detergent for 10 minutes at -90F, rinsed for 5 minutes. The swatches were dried in the air and the reflectance measured in Rd units. The results are shown in Table 11.
The cleaned swatches of A and C of Example IV were washed four more times under the washing conditions of Example IV. The changes in reflectance values of the swatches with successive washings is shown in Table 111.
TABLE III Swatch One extra Two extra Three extra Four extra wash washes washes washes Although the soil-release effects of the copolymer are not permanent, this example shows that the effects of the soil-release polymer have some effect even after several washings. In addition, the soil-release polymer did not cause graying of the dacron.
Example VI Identical dacron polyester swatches were soaked in the following aqueous soil-release polymer solutions for the indicated time periods in a tergotometer. The solutions were made pH of 3 with 4 Molar H SO fective as a 25 minute soak period, is ideally suited to Ti e. a home laundry procedure, as the rinse cycle ofa home Swatch Solution Minutes laundry procedure is generally of about 10 minutes du- A 0.01% methacrylic acid, A ethylacrylate l ration.
B 0.02% /6 methacrylic acid, V; ethylacrylate l0 C 0.01% methacrylic acid, Va ethylacrylate 25 EXAMPLE VII D 0.02% methacrylic acid, A; ethylacrylate 25 E 95 copolymer Of y alcohol and acrylic 10 A number of copolymers were evaluated for their ef- F 833 copolymfl of vinyl alcohol and acrylic 10 fectiveness in imparting soil-release characteristics to o7 dacron polyester swatches. Identical dacron polyester G 22 Polymer and acryhc 25 10 swatches were treated with 0.05% aqueous solutions of H 0.02% copolymer of vinyl alcohol and acrylic 25 the copolymers for 10 minutes in a tergotometer made acid l 0.01% hydrolyzed polyacrylamide 10 pH of 3 with 4 molar sulfuric ac d, and S011 repellancy .I 0.02% hydrolyzed polyacrylamide 10 of the treated fabric was determined from the spread- K (101% hydrolyzed p y y i 25 ing time of a colored oil drop. The copolymers are L 0.02% hydrolyzed polyacrylamlde 25 M control Soak 15 rated as to their soil-release characteristics on dacron polyester swatches in Table IV. A rating of 3 indicates clean release in seconds; a 2 rating means release in The swatches were soiled with natural skin soil ob- 100 seconds; a 1 rating means release in 500 seconds;
tained by the Trowbridge Skin Soil Method until all a 0 rating means no release in 500' seconds.
TABLE IV Acid COPOLYMER Equivalent Weight Rating Partially hydrolyzed polyacrylamide 110 2 Hydrolyzed maleic anhydride/methyl vinyl ether 87 0 Partially hydrolyzed polyacrylamide 250 0 $1; methacrylic acid, A: ethylacrylate 125 3 10:1 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 75 0 21:1 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 80 0 20:1 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 75 0 20:1 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 110 1 10:1 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 111 1 5:1 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 89 0 (soluble fraction) 10:4 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 107 0 (soluble fraction) 5:1 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 120 2 (insoluble fraction) 10:4 acrylic acid: 1,1 dihydroperfluoro-octyl methacrylate 127 2 (insoluble fraction) TABLE III Swatch Reflectance, Rd units It can thus be observed that the length of time of the soak period in the soil-release polymer solutions had little effect on the soil-release properties of the treated fabric. The 10 minute soak period, which is just as ef- This example illustrates that carboxylate copolymers having acid equivalent weights between about 1 10 and are effective soil-release agents for dacron polyester when deposited onto the fabric from dilute aqueous solution at pH of 3. The preferred acid equivalent weight for the carboxylate polymers is 125.
What is claimed is:
1. A composition for imparting non-permanent soil release characteristics to textile fabrics comprising an aqueous solution of a polymer derived from an ethenically unsaturated monocarboxylic acid and a lower alkyl acrylate or methacrylate, said polymer having an acid equivalent weight of from about 1 10 to 175 and a mineral acid present in an amount so that the pH of the solution of said composition is about 3.
2. A composition as defined in claim 1 wherein the ratio of said mineral acid to said polymer is about 1.5:1 to about 2.0:1.
3. A composition as defined in claim 1 wherein said acid is selected from the group consisting of acrylic, methacrylic, ethacrylic and crotonic acids.
4. A composition as defined in claim 3 wherein said acid is methacrylic acid.
5. A composition as defined in claim 1 wherein said acid is acrylic acid.
6. A composition as defined in claim 1 wherein said methacrylate is ethylmethacrylate.
7. A composition as defined in claim 1 wherein said acrylate is ethylacrylate.
8. A composition as defined in claim 1 wherein said acid is employed in amounts of about 60 to about 70% and said acrylate or methacrylate is employed in amounts of about 40 to about 30% by weight.
9. A composition as defined in claim 1 wherein said polymer has an acid equivalent of about 110 to about 135.
10. A composition as defined in claim 1 wherein said polymer has a molecular weight of about 2,000 to about 5 million.
11. A composition as defined in claim 1 wherein the molecular weight of said polymer is about one million.
12. A composition as defined in claim 1 wherein said mineral acid is selected from the group consisting of sulfuric, nitric, hydrochloric and phosphoric acids.
13. A composition as defined in claim 1 wherein said mineral acid is sulfuric acid.
14. A composition as defined in claim 13 wherein the ratio of said sulfuric acid to said polymer is about 1.5:1 to about 2.0:1.
15. A composition as defined in claim 1 wherein said polymer is a copolymer of methacrylic acid and ethylacrylate.
16. A composition as defined in claim 1 wherein said polymer is a copolymer of acrylic acid and 1,1- dihydroperfluorooctyl methacrylate.
17. A composition as defined in claim 1 wherein the ratio of said acid to said acrylate or methacrylate is about two thirds acid to about one third acrylate or methacrylate.
18. A composition as defined in claim 14 wherein the ratio of said acid to said acrylate is about two thirds to about one third.
19. A dilute aqueous solution of the composition as defined in claim 1 containing about 0.01 to about 1.0% by weight of said polymer and sufficient mineral acid to lower the pH of said solution to about 3.
20. A soil resistant synthetic fiber-containing material having an effective amount of the composition as defined in claim 1.
21. A material as defined in claim 20 wherein said fiber is selected from the group consisting of polyester, polyamide, acrylate, cellulose, cotton, viscose, regenerated cellulose and blends thereof.
22. A method of rendering synthetic fiber-containing materials soil resistant comprising applying thereto an effective amount of a solution as defined in claim 19.
23. A packaged product for imparting nonpermanent soilrelease characteristics to textile fibers comprising a walled package containing therein an amount of the composition as defined in claim 1.
UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT N0. 3,912,681 DATED October l t, 1975 INVENTOR(S) 1 Robert E. Dickson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
In the title page, in the item 7 Notice" in the left hand column, for "Aug. 20," read --Sept. 17-- Signcd and Sealed this Twenty-second D3) 0f February 1977 [SEAL] Arrest:
RUTH C. MASON C. MARSHALL DANN 8 ff Commissioner oflatems and Trademarks