Color protection in fabrics using citric acid and iminodisuccinate in fine fabric liquid detergent

Abstract

Provided is a liquid detergent that includes a liquid carrier, at least one surfactant, such as at least one anionic surfactant, and at least two chelating agents. A first of the two chelating agents includes citric acid monohydrate. A second of the two chelating agents includes iminodisuccinic acid. A use of the liquid detergent composition for the washing of fabrics. A method of making a cleaning composition comprising combining a liquid carrier, at least one surfactant, and at least two chelating agents, wherein a first of the two chelating agents comprises citric acid monohydrate and a second of the two chelating agents comprises iminodisuccinic acid.

Claims

1. A liquid detergent composition, comprising: a liquid carrier; at least one anionic surfactant; at least one anti-ashing polymer, copolymer or mixtures thereof present at a concentration of from about 0.01% to about 0.20% by weight; and at least two chelating agents, wherein a first of the two chelating agents comprises citric acid monohydrate and a second of the two chelating agents comprises iminodisuccinic acid, wherein the citric acid monohydrate is present in an amount of from 0.03% to 0.06% by weight, and wherein the iminodisuccinic acid is present in an amount of from 0.155% to 0.31% by weight.

2. The liquid detergent of claim 1, wherein the at least two chelating agents do not comprise aminotrimethylphosphonic acid.

3. The liquid detergent of claim 1, wherein the at least two chelating agents do not comprise ethylenediaminetetraacetic acid (EDTA) or its salts.

4. The liquid detergent of claim 1, wherein the citric acid monohydrate is present in an amount of 0.06% by weight, and wherein the iminodisuccinic acid is present in an amount of 0.155% by weight.

5. The liquid detergent of claim 1, wherein the at least one anionic surfactant comprises sodium lauryl sulfate (LAS), sodium lauryl ether sulfate (SLES), or combinations thereof.

6. The liquid detergent of claim 1, wherein the at least one anionic surfactant comprises a C.sub.12-C.sub.14 alcohol ethoxylate sulfate.

7. The liquid detergent of claim 1, wherein said at least one anti-ashing polymer, copolymer or mixtures thereof is present at a concentration of from about 0.05% to about 0.15% by weight.

8. The liquid detergent of claim 1, wherein said at least one anti-ashing polymer, copolymer or mixtures thereof comprises styrene/acrylic copolymer.

9. The liquid detergent of claim 1, wherein the liquid carrier comprises softened water and demineralized water.

10. A method of washing fabrics, said method comprising contacting said fabrics with the composition of claim 1.

Description

EXAMPLES

Example 1—Preparation of Liquid Detergent Compositions

(1) Various liquid detergent compositions, according to at least one embodiment described herein, were prepared. An exemplary composition (“prototype 4”) was prepared by combining the ingredients listed in and in the amounts set forth in Table 1 below.

(2) Generally, the compositions can be prepared at room temperature. Active ingredients and neutralization were added into a stainless vessel first, followed by addition of other ingredients, including the fragrance and colors. Viscosity and pH adjustments were made as needed.

(3) The liquid detergent composition of the invention may be prepared as a liquid composition. First, water may be added at room temperature, more preferably about 20° C. to about 25° C. Sulphonic acid was then added and neutralized with sodium hydroxide while the liquid composition may be agitated at about 200-1,000 rpm, preferably about 500-800 rpm, for about 2-10 minutes, preferably for about 3-5 minutes. To the agitated liquid composition, the rest of the active ingredients from Table 1 below may be added until full dispersion for about 10-20 min more preferably 15-18 min. The acid agent(s), chelant agent(s), and/or preservative agent(s) may also be added, keeping the agitation at about 200-1,000 rpm, preferably about 500-800 rpm, for about 3-15 minutes, preferably about 5-10 minutes. The combination of optional fragrance oils and/or fragrance capsules may be added at an agitation of about 200-1,000 rpm, preferably about 500-800 rpm, for about 2-10 minutes, preferably for about 3-5 minutes and finally salt is added to adjust viscosity at about 200-1,000 rpm, preferably about 500-800 rpm, for about 2-10 minutes, preferably for about 3-5 minutes. Meanwhile viscosity may be monitored in order that the final formulation meets predetermined specifications. It is noted that agitation provides a shear force that distributes the solids in the composition. However, in alternative embodiment, the shear force may be achieved using a system with standard baffling or static mixers. For example, standard baffling consist of four flat vertical plates, radially-directed (i.e., normal to the vessel wall), spaced at 90 degrees around the vessel periphery, and running the length of the vessel's straight side; standard baffle width is 1/10 or 1/12 of the vessel diameter (T/10 or T/12).

(4) TABLE-US-00001 TABLE 1 Ingredient % WATER 65.2555 SULPHONIC ACID 1.9500 DETERGENT CAUSTIC SODA 0.5500 SURFACTANT 27.5862 EMULSIFIER 0.3000 ANTIMICROBIAL 0.2500 MICROBICIDE 0.0200 OPTICAL BRIGHTENER 0.1727 OPACIFIER 0.2500 FRAGRANCE 0.3500 DYES 0.0006 CITRIC ACID MONOHYDRATE 0.0600 IMINODISUCCINATE 0.1550 RHEOLOGY MODIFIER 3.1000 TOTAL 100.0000

Example 2—Chelating Agent Concentration

(5) Four additional liquid detergent compositions (Prototypes 1-3 and 5) were prepared according to the method described in Example 1 above but with each composition comprising different amounts of iminodisuccinate acid and/or citric acid. A comparative formulation similar to that in Table 1 except not comprising iminodisuccinate acid or citric acid but instead comprising EDTA and DEQUEST® (Available from Italmatch Chemicals of Red Bank, N.J.) was prepared as prototype 6. The resulting chelating agent concentrations of each liquid detergent composition of prototypes 1-6 are shown in Table 2.

(6) TABLE-US-00002 TABLE 2 Iminodisuccinate Citric EDTA Acid Acid (w/w DEQUEST ® Prototype (w/w %) (w/w %) %) (w/w %) 1 0.155 0.12 0 0 2 0.31 0.06 0 0 3 0 0.06 0 0 4 0.155 0.06 0 0 5 0.155 0 0 0 6 0 0 0.16 0.4 (Comparative)

Example 3—Detergency

(7) Stain removal properties of the detergents protoypes 1-5 along with above were evaluated using demineralized and softened water having a maximum of total dissolved solids of 1000 mg/L and hardness of 10 mg/L. Performance of the detergents was evaluated in the presence/absence of dissolved minerals (Arsenic, Copper, Iron, Calcium, Magnesium, Sulfates, etc.) where the concentration depended as a result of processing, such as distillation, deionization, membrane filtration (reverse osmosis or nano-filtration), electrodialysis or other technologies.

(8) The conventional formulation was also evaluated as a comparative example. Four types of stains including were prepared on different fabrics. The stain types included oxidative, enzymatic, particulate and oleos. The fabric types included cotton, polyester, wool, rayon, nylon, nylon & lycra, polyester, and polyester lycra & cotton. After the stains were prepared, each of the fabrics was washed. The conditions for the wash included water at 150 ppm, 2.5kg of fabric load, one wash cycle and at room temperature.

(9) The sample swatches of fabric were stitched in linen fabric. The test was conducted in triplicate. Comparative swatches with no stains and those swatches that were stained were measured in Hunter Lab L*a*b equipment in order to obtain quantitative values for the color spectrum. After washing the samples, the amount of the stain removed was calculated (shown as amount removed in % in Table 3). The results of these calculations are shown in Table 3 below.

(10) TABLE-US-00003 TABLE 3 Cosmetic Cosmetic Blood, Artificial Chocolate Red Makeup/ Olive Makeup/ Milk Perspiration Ice cream wine Nylon Oil Nylon/lycra & Ink Coffee Avg. ID (%) (%) (%) (%) (%) (%) (%) (%) (%) Water 59.90 83.68 48.60 82.41 −10.94 57.83 17.29 58.59 49.67 Prototype 1 68.31 95.63 51.32 95.15 9.10 88.15 20.96 63.68 61.54 Prototype 2 71.69 95.31 53.11 92.50 23.35 84.22 23.51 61.16 63.11 Prototype 3 ( 62.22 92.07 51.46 86.20 21.80 74.80 20.77 60.19 58.69 Prototype 4 52.17 95.38 53.91 97.48 42.58 84.83 22.45 64.85 64.21 Prototype 5 78.84 96.24 57.11 94.45 41.99 84.38 21.30 62.99 67.17 Prototype 6 80.19 96.11 53.59 89.32 36.12 77.34 20.04 64.37 64.64 (Comparative)

(11) As seen in Table 3, there is a tendency toward improvement in stain removal as the amount of iminodisuccinate acid (“imino”) is increased across the different liquid detergent formulations. For example, in Table 3 above, prototype 3 (0% imino; 0.06% citric acid) showed an average of 58.69% stain removal, prototype 1 (0.155% imino; 0.12% citric acid) showed an average of 61.54% stain removal and prototype 2 (0.31% imino; 0.06% citric acid) showed an average of 63.11% stain removal.

Example 4—Color Protection

(12) Color protection properties of the detergents of prototypes 1- were evaluated. An additional formulation similar to prototype 1 except comprising 0.21 w/w% iminodisuccinic acid and 0.03 w/w % citric acid, which was determined by a DOE statistical analysis, was prepared as prototype 7. A conventional formulation (shown as prototype “water” in Table 4, and a Standard Detergent without optical brightener (listed as prototype “wob”) that is used in AATCC Test Methods was also evaluated as a comparative example.

(13) To evaluate color protection, three different fabrics (cotton, polyester and nylon) at different colors each (blue and pink) were each washed with the different liquid detergent formulations. The same was done with the conventional detergent, the standardized detergent without brightener and water. Each of the fabrics was washed together in a tergotometer with a respective one of a multifiber fabric. After each wash, the multifiber fabric was inspected. Each multifiber fabric was scored based on initial and final values of reflectivity as measured by Hunter L,a,b equipment. The resulting transfer grade scores for each of the mediums are shown in Table 4 below.

(14) TABLE-US-00004 TABLE 4 Prototype Sum of Transfer Grade* Water 62 1 82 2 80 3 72 4 86 5 72 6 63 7 77 wob 67 *Higher value = better performance for color protection

(15) Based on the transfer grade results, it was determined that the liquid detergent composition of Example 1 (prototype 4) performed better than the other compositions at protecting the color of the colored samples and prevented the most amount of color transfer to the multifiber fabric during a wash cycle due to the unexpected synergy between iminodisuccinate and citric acid in some liquid detergent compositions. In light of the results shown in Tables 3 and 4 for prototypes 1, 2, 4 and 7 there is an unexpected jump in overall improvement—that is, detergency and color protection considered together—for the formulations that combine the increased amount of iminodisuccinate with certain volumes of citric acid according to compositions described herein.