CATIONIC SURFACTANT AND ITS USE IN LAUNDRY DETERGENT COMPOSITIONS

Abstract

Described herein is a cationic surfactant. Also described herein is a method of using the cationic surfactant, the method including using the cationic surfactant in laundry detergent compositions (for example in combination with an anionic surfactant, nonionic surfactant and/or enzyme).

Claims

1. A laundry detergent composition, comprising at least one cationic surfactant of the formula X.sup.− ##STR00006## wherein X represents an anionic counterion, n is from 1 to 5, R1 are independently from each other selected from the group consisting of —CH3, —C2H5, and —C3H7, R2 is selected from the group consisting of linear, branched or cyclic alkyl moieties with 4 to 18 C atoms and R3 independently from each other represent hydrogen, at least one enzyme, and optionally at least one compound selected from the group consisting of anionic surfactants and nonionic surfactants.

2. The laundry detergent composition according to claim 1, wherein X is selected from the group consisting of —OSO3Me.sup.−, —Cl.sup.−, —I.sup.− and —Br.sup.−.

3. The laundry detergent composition according to claim 1, wherein n is 1.

4. The laundry detergent composition according to claim 1, wherein R1 represents —CH3.

5. The laundry detergent composition according to claim 1, wherein R2 is selected from the group consisting of alkyl moieties with 4, 6, 8, 10, 12 C atoms.

6. The laundry detergent composition according to claim 1, wherein X is selected from the group consisting of —OSO3Me.sup.− and —Cl.sup.−, n=1, R1 represents —CH3, R2 is a linear alkyl moiety with 10 C atoms and R3 is hydrogen.

7. The laundry detergent composition according to claim 1, wherein the laundry detergent composition is a liquid laundry detergent composition.

8. The laundry detergent composition according to claim 1, comprising additionally at least one anionic surfactant.

9. The laundry detergent composition according to claim 8, wherein the anionic surfactant is a sulfate or sulfonate or combinations thereof.

10. The laundry detergent composition according to claim 8, wherein the anionic surfactant is selected from the group consisting of alkylether sulfates and alkylbenzene sulfonates or combinations thereof.

11. The laundry detergent composition according to claim 8, wherein the ratio between the cationic surfactant and the anionic surfactant is in the range of 1:1 to 1:10.

12. The laundry detergent composition according to claim 1, comprising additionally at least one nonionic surfactant.

13. The laundry detergent composition according to claim 12, wherein the ratio between the cationic surfactant and the nonionic surfactant is in the range of 1:0-1:10.

14. The laundry detergent composition according to claim 1, wherein the enzyme is selected from the group consisting of proteases, amylases, mannanases, lipases and cellulases.

15. The laundry detergent composition according to claim 14, wherein the amount of lipase in the laundry detergent composition lipase is 0.0002%-0.02% by weight active, relative to the total weight of the composition.

16. The laundry detergent composition according to claim 1, comprising at least one anionic surfactant, at least one nonionic surfactant and at least one enzyme.

17. A method of using a cationic surfactant of the formula X.sup.− ##STR00007## wherein X represents an anionic counterion, n is from 1 to 5, R1 are independently from each other selected from the group consisting of —CH3, —C2H5, and —C3H7, R2 is selected from the group consisting of linear, branched or cyclic alkyl moieties with 4 to 18 C atoms and R3 independently from each other represent hydrogen, the method comprising using the cationic surfactant for increasing enzyme stability in a laundry detergent composition comprising at least one enzyme.

18. A process for removing fatty stains on a textile fabric, the processing comprising using the laundry detergent composition according to claim 1.

19. The laundry detergent composition according to claim 1, wherein X is —OSO3Me.sup.− or —Cl.sup.−.

20. The laundry detergent composition according to claim 1, wherein R2 is selected from the group consisting of alkyl moieties with 10 C atoms.

Description

EXAMPLES

[0130] In the following paragraphs, some experimental examples are presented to illustrate certain aspects of the present invention.

[0131] A cationic surfactant was synthesized as follows. (Inventive cationic surfactant “I”)

[0132] 2-[2-(dimethylamino)ethoxy]ethanol (0.75 mol) and sodium ethylate (dissolved in Methanol) (0.025 mol) were placed into a 500 mL four-necked flask under nitrogen atmosphere and heated up to 60° C. under stirring. Then Methanol was removed under vacuum at 60° C. The mixture was heated up to 160° C. and dodecene epoxide was added at 160° C. over a period of 2.5 h. To complete the reaction, the mixture post-reacted for 5 h. The control of reaction was carried out by total amine- and epoxide value. After vacuum distillation the tertiary amine compound was obtained in 95% purity having an amine number of 169.3 mg/g.

[0133] .sup.1H-NMR (400 MHz, CDCl.sub.3): δ (ppm)=0.82 (t, 3H, —CH.sub.3), 1.20-1.37 (d, 18H, (—CH.sub.2).sub.9), 2.20 (dd, 6H, —N(CH.sub.3).sub.2), 2.45 (t, 2H, CH.sub.2—O), 3.25 (m, 2H, —N(CH.sub.2).

[0134] In a final step, the cationic surfactant was achieved by quaternization with dimethylsulfate, methyl chloride or propylene oxide in combination with an acid such as hydrogen chloride.

[0135] The tertiary amine compound (97 g) and water (400 g) were placed into a 5-I autoclave. After nitrogen neutralization, the pressure was adjusted to 5.0 bar and the mixture was homogenized at 86° C. for 1.5 h. Then Methyl chloride (14.4 g) was added. To complete the reaction, the mixture was post-reacted for 4 h at 86° C. The cationic surfactant was achieved with an active content of 21.3%

[0136] .sup.1H-NMR (400 MHz, CDCl.sub.3): δ (ppm)=0.90 (t, 3H, —CH.sub.3), 1.28-1.45 (d, 18H, (—CH.sub.2).sub.9), 3.25 (dd, 8H, —N(CH.sub.3).sub.3), 3.25 (t, 2H, CH.sub.2—O), 3.25-4.00 (m, 12H).

[0137] Comparative cationic surfactant (“C”) was synthesized as follows.

[0138] 155 g 1-dimethylamino-2-propanol (1.5 mol) and 2.2 g potassium tert-butoxide (0.20 mol) were charged into a stainless-steel reactor and degassed with nitrogen. The reactor is set under 2 bar nitrogen pressure and heated to 130° C. 958 g propylene oxide (16.5 mol) are dosed into the system within 12 hours. The reaction mixture is allowed to post react for 12 hours at 130° C. Volatile compounds are removed in vacuo and 1120 g of a yellow liquid was obtained as product.

[0139] .sup.1H NMR (500 MHz, Chloroform-d): δ(ppm)=4.02-3.10 (m, J=6.0, 2.8 Hz, 33H, —CH, —CH.sub.2), 2.25 (s, 6H, —CH.sub.3), 1.26-0.99 (m, 36H, —CH.sub.3).

[0140] 200 g of the obtained product (0.27 mol) were charged into a flask, flushed with nitrogen and heated to 75° C. Then, 34 g of dimethyl sulfate (DMS) (0.27 mol) were dosed into the system, keeping the internal temperature between 70 and 75° C. After the addition, the reaction mixture was allowed to post-react at 75° C. for two hours. After confirmation of absence of DMS, the reaction mixture was neutralized using 7.15 g of sodium hydroxide solution (50%).

[0141] .sup.1H NMR (500 MHz, Chloroform-d) δ (ppm)=3.97-2.98 (m, 50H, —CH, —CH.sub.2, —N+—(CH.sub.3).sub.3), 1.48-0.74 (m, 36H, —CH.sub.3).

[0142] Then, laundry detergent compositions containing the cationic surfactant were prepared.

[0143] Formulations (i.e. laundry detergent compositions) containing the above inventive cationic surfactant (L2), a reference formulation (L1) and a further reference formulation (L3) were manufactured as follows:

[0144] L1 was prepared by the stepwise addition of 40 wt % high purity water to 5.5 wt % Maranil, followed by the addition of 6 wt % monopropylene glycol (MPG) and 3 wt % ethanol. 5.4 wt % Lutensol A07 was added and the mixture was stirred ˜30 minutes at 50-60° C. 2.5 wt % Edenor K12-18 was added and the mixture was stirred until everything was dissolved. After the addition of 3 wt % sodium citrate (tribasic) and 5.4 wt % Texapon N70, the mixture was stirred 15 minutes at 50° C. to reach a homogeneous formulation. The pH value was adjusted with sodium hydroxide to 8.2 and the formulation was allowed to cool down to room temperature at which the pH value was re-adjusted, if necessary. The final concentration was adjusted by filling up the formulation with high purity water, leaving a 10 wt % gap for the addition of the enzyme solution.

[0145] L2 and L3 were prepared by the stepwise addition of 40 wt % high purity water to Maranil (5.5% wt % active ingredient), followed by the addition of 6 wt % monopropylene glycol (MPG) and 2 wt % ethanol. 5.4 wt % Lutensol A07 was added and the mixture was stirred at 50-60° C. for approximately 30 min. Edenor K12-18 (2.5 wt %) was added and the mixture was stirred until everything was dissolved. After the addition of 3 wt % sodium citrate (tribasic) and 1.35 wt % of the corresponding cationic surfactant, the mixture was stirred 15 minutes at 50° C. to reach a homogeneous formulation. The pH value was adjusted with sodium hydroxide (10 wt % aq) to 8.2 and the formulation was allowed to cool down to room temperature. The pH value was checked again once the formulation temperature reached room temperature and was re-adjusted, if necessary. The final concentration was adjusted by filling up the formulation with high purity water, leaving a 10 wt % gap for the addition of the enzyme solution.

[0146] L2 was first characterized with respect to their physicochemical properties at 23° C. in direct comparison to a remake of benchmark formulation L1. For this purpose, the formulation was diluted to a total surfactant content of 50 ppm. Static surface tension (SST) measurements based on the pendant drop technique (drop shape analysis on a Kruss DSA100 instrument, using droplets of formulation with a volume of approx. 7 μL) show that L2 reaches values that are similar, or even slightly lower (which is expected to be beneficial for cleaning applications), than the benchmark system, both after 1 and 60 s of equilibration in air:

TABLE-US-00001 TABLE 1 Surface Tension [mNm−1] 1 s 60 s L1 46.21 30.84 L2 45.90 29.84

[0147] Interfacial tensions (IFT) measured by the pendant drop technique (drop shape analysis on a Kruss DSA100 instrument, using droplets of formulation with a volume of approx. 7 μL) against triolein as oil phase (outer reservoir of about 3 mL in a conventional cuvette) confirm this observation and show a clear benefit of L2 relative to the benchmark formulation L1 (lower IFT values imply that the studied oil can more readily be solubilized and/or emulsified by the respective formulation; note that triolein is a typical oily component of common fatty stains):

TABLE-US-00002 TABLE 2 Interfacial Tension vs. triolein [mNm−1] 1 s 60 s L1 12.28 6.29 L2 5.32 3.08

[0148] Finally, the ability of L2 to spread on relevant stains was assessed by determining the contact angle (wetting behavior) of the dilute solutions on thin layers of fatty stains applied on a glass substrate by melting, doctor-blading of a ca. 40 wt % solution of the respective stain in toluene and subsequent cooling. By analyzing the shape of a sessile drop of formulation (volume: ca. 2 μL) on the stain layer after different equilibration times (1 and 60 s) using a Kruss DSA100 instrument, the corresponding contact angle was measured (based on the tangent method). The following table shows the results obtained when using commercial lard as a model stain; again, lower values are more beneficial as they indicate a better wettability of the stain surface, which is considered to be crucial for final removal:

TABLE-US-00003 TABLE 3 L1 L2 Contact Contact Contact Contact Stain Angle/1 s Angle/60 s Angle/1 s Angle/60 s Biskin 95.4 80.4 94.7 83.2 Lard 77.3 66.4 64.2 53.4 Beef tallow 80.9 62.1 92.2 67.6 Sebum 70.3 60.9 69.4 62.9 Tripalmitin 84.9 72.2 90.3 82.6 Tripalmitin/ 98.4 79.7 99.9 77.3 Triolein

[0149] As in the case of the surface and interfacial tension, L2 (containing Maranil® as anionic surfactant, Lutensol® A07 as nonionic surfactant, and the inventive cationic surfactant) shows a superior effect in terms of wetting of the stain surface.

[0150] Enzyme Activity/Storage Stability:

[0151] The samples were stored in a drying cabinet at 37° C. During the testing period, aliquots were taken at defined time points and frozen at −20° C. until the determination of the enzyme activity. For the enzyme activity measurements, the samples were allowed to reach room temperature. The enzyme activity was determined at 30° C. with an in-house developed absorption-based assay using the Gallery™ machine. The Gallery™ is a semi-automated photometric analyzer with an error ≤2.5%. For the analysis, the residual enzyme activity for each time point compared to the enzyme activity at day 0 is calculated.

TABLE-US-00004 TABLE 4 Relative Enzyme Activity/% Storage Time/d Formulation L2 Formulation L1 0 100.0 ± 0.4  100.0 ± 1.6  2 91.7 ± 1.6 85.8 ± 2.2 7 51.1 ± 1.6 39.5 ± 0.5 28 16.4 ± 1.2 12.6 ± 2.0

[0152] After 28 d of storage at elevated temperature (37° C.), a relative residual enzyme activity of ˜16% was found for L2 (inventive surfactant formulation) compared to only ˜13% relative residual enzyme activity for L1 (benchmark). This means that the laundry lipase Lipex is 3% more stable in the here described inventive formulation L2 compared to the benchmark formulation L1.

[0153] Tests on detergency performance, i.e. washing or cleaning performance

[0154] General:

[0155] As lipase, commercially available Lipex® from Novozymes was used.

[0156] The primary washing performance of the inventive cationic surfactant was tested in the washing machine preparing wash solutions using water of 14° dH (2.5 mmol/L; Ca:Mg:HCO.sub.3 4:1:8) containing 4.0 g/L of the liquid test detergent L.1 and L.2 (see composition in Table 5) and/or in combination with 0.02% by weight active Lipex® (relative to the total weight of the composition).

[0157] Test formulation L.1 as reference does not contain the inventive cationic surfactant. In formulation L.2 lauryl ether sulphate (5%) from L.1 has been substituted by a certain amount of the inventive cationic surfactant. In formulation L.3, comparative surfactant “C” was used instead of the inventive surfactant “I”.

TABLE-US-00005 TABLE 5 Liquid Test Detergent Formulations Ingredients Liquid Detergent Formulations L.1 L.2 L.3 Alkylbenzene sulfonic acid (C.sub.10-C.sub.13), 5.5% 5.5%.sup.  5.5%.sup.  Na salt C.sub.13/C.sub.15-Oxoalkohol reacted with 5.4% 5.4%.sup.  5.4%.sup.  7 moles of EO 1,2 propyleneglycol .sup. 6% 6% 6% ethanol .sup. 2% 2% 2% potassium coconut soap 2.4% 2.4%.sup.  2.4%.sup.  NaOH 2.2% 2.2%.sup.  2.2%.sup.  sodium citrate .sup. 3% 3% 3% lauryl ether sulphate 5.4% 0% 0% cationic surfactant “I” (inventive) .sup. 0% 1.35%   0% Cationic surfactant “C” (comparative) .sup. 0% 0% 1.35%  

[0158] The test was performed in a washing machine (Miele SOFTTRONIC W 1935 WTL, 30° C., short program, 1200 rpm, 3.5 kg ballast load), where two multi-stain monitors (MS1 and MS2) were washed together with four SBL-2004 sheets (wfk Testgewebe GmbH, DE; corresponding to 32 grams of ballast soil) as additional soil ballast. The multi-stain monitors MS1 and MS2 (Table 6) contain respectively 14 and 3 standardized soiled fabrics, of respectively 5.0×5.0 cm and 4.5×4.5 cm size and stitched on two sides to a polyester carrier.

TABLE-US-00006 TABLE 6 Multi-stain monitors used for the evaluation of the cleaning performance MS1: EMPA 142/1: polyester/cotton (65/35) soiled with lipstick wfk 10D: pigment/sebum on cotton CFT C-S-67: mustard on cotton CFT PC-S-04: saturated with colored olive oil on Polyester/Cotton (65/35) CFT C-S-170: chocolate mousse, aged on cotton CFT-C-S-68: chocolate ice cream on cotton CFT-C-09: pigment/oil not according to Australian standard on cotton CFT C-S-61: beef fat, coloured on cotton CFT C-S-79: napolina tomato on cotton CFT C-S-17: fluid make-up on cotton CFT C-S-75: blood/beef fat on cotton CFT C-S-06: salad dressing with natural black on cotton CFT C-S-44: chocolate drink, pure on cotton CFT C-S-38: egg yolk, with carbon black, aged by heating, on cotton MS2: CFT C-S-10: butterfat with colorant on cotton CFT C-S-62: lard, colored on cotton CFT C-S-61: beef fat, colored on cotton

[0159] The total level of cleaning was evaluated using color measurements. With the aid of the CIELab color space classification, the brightness L*, the value a* on the red—green color axis and the b* value on the yellow—blue color axis, were measured before and after washing and averaged for the 16 and 4 stains of the monitors respectively using the MACH5 Multi Area Color-measurement from Colour Consult. The change of the color value (Delta E, ΔE), defined and calculated automatically by the evaluation color tools on the following formula

ΔE*.sub.ab=√{square root over (ΔL.sup.*2+Δa.sup.*2+Δb.sup.*2)}

which is a measure of the achieved cleaning effect.

[0160] Higher Delta E values show better cleaning. For each stain, a difference of 1 unit can be detected visually by a skilled person. A non-expert can visually detect 2 units easily. The ΔE values of the formulations L.1, L.2 and L.3 for the sum of the 14 and 4 stains of correspondingly MS1 and MS2 and for selected single stains are shown in Table 7. Calculation of ΔE values is software-based, and it occurs automatically. Washing machine results show a better cleaning performance for the formulation L.2. containing the inventive cationic surfactant “I” and no lauryl ether sulphate component. Results also demonstrate that the total additional cleaning performance benefit of the lipase is higher for L.2, demonstrating a synergism benefit when combining the cationic surfactant and the lipase in a formulation with no lauryl ether sulphate. The formulation L.3 as comparative example containing the cationic surfactant “C” shows no cleaning performance benefit on the tested stains.

TABLE-US-00007 TABLE 7 Results of washing machine test fabric monitors ΔE ΔE ΔE ΔE (CFT (CFT (CFT (CFT Total ΔE C-S-61) C-S-75) C-09) C-S-68) Formulation MS1 + MS2 MS2 MS1 MS1 MS1 L.1 276 27.9 27.6 7.9 15.3 L.2 291 29.8 29.6 8.8 16.3 L.3 273 27.2 27.1 7.8 15.0 L.1 + 290 31.4 28.0 9.0 17.0 0.02% by weight active Lipex ® L.2 + 320 37.8 33.0 10.8 19.0 0.02% by weight active Lipex ®