Laundry Detergents Containing Soil Release Polymers

Abstract

The invention relates to liquid laundry detergent compositions comprising a) one or more polyesters comprising one or more of the repeating structural unit (a1) and one or more of the repeating structural unit (a2)

##STR00001## wherein G.sup.1 is one or more of (C.sub.nH.sub.2nO) with n being a number of from 2 to 10, R.sup.1 is H or COR.sup.2, R.sup.2 is X—(C.sub.3H.sub.6O).sub.p—(C.sub.2H.sub.4O).sub.q—Y wherein X is NH or O, Y is a C.sub.1-30 alkyl, the (C.sub.3H.sub.6O)— and (C.sub.2H.sub.4O)-groups may be arranged blockwise, alternating, periodically and/or statistically and wherein the connections of the groups (C.sub.3H.sub.6O)— and (C.sub.2H.sub.4O)— to X— and —Y are free to vary, or O-G.sup.1-H, p is based on a molar average, a number of from 0 to 60, q is based on a molar average, a number of from 1 to 300,
and b) one or more surfactants.

The one or more polyesters of component a) possess advantageous stability in alkaline environments, possess beneficial solubility and advantageously are clearly soluble in alkaline compositions such as liquid laundry detergent compositions and also possess advantageous soil release and soil removal properties on fatty and oily stains.

Claims

1. A liquid laundry detergent composition comprising a) at least one polyester having an average molecular weight (M.sub.w) from 3000 to 40000 g/mol comprising at least one of the repeating structural unit (a1) and at least one of the repeating structural unit (a2) ##STR00020##  wherein G.sup.1 is at least one of (C.sub.2H.sub.4O), (C.sub.3H.sub.6O) or (C.sub.4H.sub.8O), R.sup.1 is H or COR.sup.2, R.sup.2 is X—(C.sub.3H.sub.6O).sub.p—(C.sub.2H.sub.4O).sub.q—Y wherein X is NH, Y is a C.sub.1-4 alkyl the (C.sub.3H.sub.6O)— and (C.sub.2H.sub.4O)-groups may be arranged blockwise, alternating, periodically and/or statistically, and wherein the connections of the groups (C.sub.3H.sub.6O)— and (C.sub.2H.sub.4O)— to X— and —Y are free to vary, p is based on a molar average, a number of from 0 to 60, q is based on a molar average, a number of from 1 to 300, wherein the polyesters besides the at least one repeating structural unit comprise terminal groups which are connected to the CO group of the repeating structural units (a1) and (a2) and which are selected from the group consisting of HO, OCH.sub.3, HOG.sup.1 and R.sup.2 or which are connected to the G.sup.1 group of the repeating structural units (a1) and (a2) and which are selected from the group consisting of H, CO(C.sub.6H.sub.4)COR.sup.2 and CO(C.sub.6H.sub.2)COR.sup.2R.sup.1COR.sup.2, wherein R.sup.1 and R.sup.2 are defined above, and b) at least one surfactant, wherein the at least one polyester of component a) are present in an amount from 0.1 wt.-% to 10 wt.-%, based on the total weight of the liquid laundry detergent composition, and the at least one surfactant of component b) are present in an amount from 5 wt.-% to 65 wt.-%, based on the total weight of the liquid laundry detergent composition.

2. The liquid laundry detergent composition according to claim 1, wherein the at least one repeating structural unit (a2) is selected from the group consisting of the repeating structural units (a2.1) and (a2.2). ##STR00021##

3. The liquid laundry detergent composition according to claim 1, wherein the sum of p and q, based on a molar average, is a number of from 1 to 360.

4. The liquid laundry detergent composition according to claim 1, wherein the at least one polyester of component a) additionally comprises at least one of the repeating structural unit (a3) ##STR00022## wherein G.sup.1 is at least one of (C.sub.2H.sub.4O), (C.sub.3H.sub.6O) or (C.sub.4H.sub.8O), and X.sup.+ is a counter-ion.

5. The liquid laundry detergent composition according to claim 1, wherein the average number of repeating structural unit (a1) in the at least one polyester of component a) is from 2 to 200, and the average number of repeating structural unit (a2) in the at least one polyester of component a) is from 1 to 25.

6. The liquid laundry detergent composition according to claim 1, wherein the ratio of the average number of repeating structural unit (a1) in the at least one polyester of component a) to the average number of repeating structural unit (a2) in the at least one polyester of component a) is from 2 to 8.

7. The liquid laundry detergent composition according to claim 1, wherein the total amount of repeating structural units (a1) and (a2) in the at least one polyester of component a), based on the total weight of the at least one polyester of component a), is at least 30 wt.-%.

8. The liquid laundry detergent composition according to claim 4, wherein the amount of repeating structural unit (a3) in the at least one polyester of component a), based on the total weight of the at least one polyester of component a), is at least 0.1 wt.-%.

9. The liquid laundry detergent composition according to claim 1, wherein the repeating structural units of the at least one polyester of component a) are exclusively selected from the group consisting of repeating structural units (a1) and (a2).

10. The liquid laundry detergent composition according to claim 1, wherein G.sup.1 is (C.sub.3H.sub.6O).

11. The liquid laundry detergent composition according to claim 1, wherein the at least one polyester of component a) comprise repeating structural units exclusively selected from the group consisting of the repeating structural units (a1) and (a2), whereby at least one of the repeating structural unit (a1) and at least one of the repeating structural unit (a2) must be present ##STR00023## wherein G.sup.1 is (C.sub.3H.sub.6O), R.sup.1 is H, R.sup.2 is X—(C.sub.3H.sub.6O).sub.p—(C.sub.2H.sub.4O).sub.q—Y wherein X is NH, Y is a C.sub.1-4 alkyl, the (C.sub.3H.sub.6O)— and (C.sub.2H.sub.4O)-groups may be arranged blockwise, alternating, periodically and/or statistically, and wherein the connections of the groups (C.sub.3H.sub.6O)— and (C.sub.2H.sub.4O)— to X— and —Y are free to vary, p is based on a molar average, a number of from 0 to 15, q is based on a molar average, a number of from 12 to 120.

12. The liquid laundry detergent composition according to claim 11, wherein p, based on a molar average, is a number of from 2 to 15.

13. The liquid laundry detergent composition according to claim 1, wherein the at least one polyester of component a) is present in an amount from 0.2 wt.-% to 5 wt.-% based on the total weight of the liquid laundry detergent composition.

14. The liquid laundry detergent composition according to claim 1, wherein the at least one surfactant of component b) is selected from the group consisting of anionic, nonionic, cationic and zwitterionic surfactants.

15. The liquid laundry detergent composition according to claim 14, wherein the at least one surfactant of component b) is selected from the group consisting of linear alkyl benzene sulfonates, alkyl ether sulfates, nonionic surfactants, amine oxides and betaines.

16. The liquid laundry detergent composition according to claim 1, wherein the at least one surfactant of component b) is present in an amount from 6 to 60 wt.-% based on the total weight of the liquid laundry detergent composition.

Description

EXAMPLES

[0244] The examples below are intended to illustrate the invention in detail without, however, limiting it thereto. Unless explicitly stated otherwise, all percentages given and relating to material amounts are percentages by weight (% by wt. or wt.-%).

[0245] Polymer Preparation

[0246] The polyesters of component a) of the inventive liquid laundry detergent compositions are prepared by methods well known to the person skilled in the art. A general description is given in the following.

[0247] A mixture of sodium acetate (NaOAc) and titanium isopropoxide (TIP) is preferably used as the catalyst system in the preparation.

[0248] The following abbreviations and materials are used: [0249] Endcap 1 amine-terminated methyl-ethoxylated-propoxylated polyether with an average molecular weight of 2000 g/mol, an average molar ratio of EO to PO of 4 to 1 and the EO and PO units distributed statistically [0250] Endcap 2 monomethyl-ethoxylated-polyether with an average molecular weight of 2000 g/mol [0251] Endcap 3 monomethyl-ethoxylated-propoxylated polyether mono-ol with an average molecular weight of 2100 g/mol, the molar average number of EO units being 45, the molar average number of PO units being 2, and the EO and PO units being distributed blockwise [0252] TMAA Trimellitic acid anhydride [0253] PMADA Pyromellitic acid dianhydride [0254] DMT Dimethylterephthalate [0255] PG 1,2-propylene glycol [0256] BG 2,3-butylene glycol [0257] TIP titanium isopropoxide [0258] NaOAc sodium acetate [0259] a.m. active matter

[0260] General Procedure for the Preparation of the Polyesters

[0261] The polyester synthesis is carried out in either a two-step or a three-step procedure by the reaction of dimethyl terephthalate (DMT), a tri-basic or tetra-basic acid or acid anhydride, preferably trimellitic acid anhydride (TMAA) or pyromellitic acid dianhydride (PMADA), one or more alkylene glycols, preferably 1,2-propylene glycol (PG), alkyl capped polyalkylene glycol and optionally additional monomers V), using sodium acetate (NaOAc) and titanium isopropoxide (TIP) as the catalyst system.

[0262] In the three-step procedure, a precursor is first synthesized by reacting exclusively the relevant acid anhydride with the relevant alkyl capped polyalkylene glycol.

[0263] Precursor Synthesis (for Three Step Procedure)

[0264] The alkyl capped polyalkylene glycol is weighed into a five neck round-bottom flask and the contents heated to 50° C. under stirring and a continuous nitrogen flow of 5 l/h. The relevant acid anhydride is added and the mixture is stirred for 30 minutes at 50 to 60° C. and then for 1 hour at 150° C. After that the pressure is reduced to 10 mbar within 30 minutes. After 2 hours at 150° C./10 mbar the mixture is allowed to cool.

[0265] Transesterification

[0266] For the three step procedure, the DMT, one or more alkylene glycols, optional additional monomers V) and a catalytic amount of NaOAc are added to the five neck round-bottom flask containing the cooled precursor.

[0267] For the two step procedure, the alkyl capped polyalkylene glycol is weighed into a five neck round-bottom flask and the contents heated to 50° C. under stirring and a continuous nitrogen flow of 5 l/h. The acid anhydride, DMT, one or more alkylene glycols, optional additional monomers V) and a catalytic amount of NaOAc are then added.

[0268] For both the two-step and three-step procedures, the mixture is then carefully heated in 1 hour to 170° C. for melting and homogenization purposes. At a temperature of about 80′C the TIP (e.g. 0.2 g) is added. Within 1 hour the temperature is raised to 210° C. When the temperature inside the reaction vessel has reached 180° C., the reaction mixture is purged by a nitrogen stream (5 l/h). During the transesterification, methanol is formed and released from the reaction mixture and is distilled out of the system (distillation temperature <55° C.). After stirring the mixture for 2 hours at 210° C., the nitrogen stream is switched off and the pressure is reduced to 600 mbar within 1.5 hours. The pressure is then reduced to 500 mbar within 1.5 hours.

[0269] Polycondensation

[0270] The mixture is heated to 230° C. At this temperature the pressure is again set to 500 mbar over a time span of 20 minutes, to 200 mbar within 50 minutes and to mbar within 80 minutes. After that, the pressure is reduced within 10 minutes to 1 mbar. The mixture is stirred for 4 hours at 230° C. at 1 mbar. The reaction mixture is cooled down to 160° C. Vacuum is broken with nitrogen and the molten polymer is stored in a glass jar.

Example I—Three-Step Procedure: Endcap 1+PG+TMAA

[0271]

TABLE-US-00001 Amount [g] Raw Material [Abbreviation] 19.2 TMAA 200 Endcap 1 77.7 DMT 61.0 PG 0.5 NaOAc 0.2 TIP

Example II—Three-Step Procedure: Endcap 1+PG/BG+TMAA

[0272]

TABLE-US-00002 Amount [g] Raw Material [Abbreviation] 19.2 TMAA 200 Endcap 1 77.7 DMT 49.0 PG 14.0 BG 0.5 NaOAc 0.2 TIP

Example III—Three-Step Procedure: Endcap 2+PG+TMAA

[0273]

TABLE-US-00003 Amount [g] Raw Material [Abbreviation] 19.2 TMAA 200 Endcap 2 77.7 DMT 61.0 PG 0.5 NaOAc 0.2 TIP

Example IV—Two-Step Procedure: Endcap 2+PG+TMAA

[0274]

TABLE-US-00004 Amount [g] Raw Material [Abbreviation] 19.2 TMAA 200 Endcap 2 77.7 DMT 61.0 PG 0.5 NaOAc 0.2 TIP

Example V—Three-Step Procedure: Endcap 3+PG+TMAA

[0275]

TABLE-US-00005 Amount [g] Raw Material [Abbreviation] 19.2 TMAA 200 Endcap 3 77.7 DMT 61.0 PG 0.5 NaOAc 0.2 TIP

Example VI—Two-Step Procedure: Endcap 3+PG+TMAA

[0276]

TABLE-US-00006 Amount [g] Raw Material [Abbreviation] 19.2 TMAA 200 Endcap 3 77.7 DMT 61.0 PG 0.5 NaOAc 0.2 TIP

Example VII—Three-Step Procedure: Endcap 1+PG+PMADA

[0277]

TABLE-US-00007 Amount [g] Raw Material [Abbreviation] 10.9 PMADA 200 Endcap 1 48.6 DMT 38.1 PG 0.5 NaOAc 0.2 TIP

[0278] Liquid laundry detergent compositions containing exemplary polyesters A series of liquid laundry detergent compositions comprising the exemplary polyester prepared according to Example I, were prepared according to Table A in order to demonstrate the ability of incorporating the polyesters into laundry compositions.

TABLE-US-00008 TABLE A Compositions containing polyester from Example I wt.-% a.m. Ingredient 1 2 3 4 5 6 7 LAS 5.2 5.2 6.0 9.0 11.2 12.0 14.3 SLES 2EO 6.5 6.5 6.0 9.0 4.2 9.0 0.0 NI 7EO 5.2 5.2 12.6 8.4 8.8 6.3 10.0 Fatty Acid 2.8 2.8 5.4 3.6 3.8 2.7 4.3 Propylene Glycol 0.0 0.0 5.0 5.0 4.8 5.0 4.9 Glycerol 2.4 2.4 0.8 0.8 0.8 0.8 0.8 Ethanol 1.2 1.2 0.0 0.0 0.0 0.0 0.0 Citric Acid 1.7 1.7 3.9 3.9 3.7 3.9 3.7 Sodium tetraborate 2.0 2.0 0.0 0.0 0.0 0.0 0.0 decahydrate SRP1 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Demin water and ad 100 ad 100 ad 100 ad 100 — — — NaOH to adjust pH Demin water and — — — — ad 100 ad 100 ad 100 TEA to adjust pH pH Value 8.5 8.5 7.5 7.6 7.5 7.6 7.6 Appearance at clear clear clear clear clear clear clear room temperature

[0279] Key to Ingredients Used in the Compositions of Tables A and B: [0280] LAS is C.sub.12-14 linear alkylbenzene sulfonate, sodium salt [0281] SLES 2EO is sodium lauryl ether sulfate with 2 moles EO (Genapol® LRO, Clariant). [0282] NI 7EO is C.sub.12-15 alcohol ethoxylate 7EO nonionic (Genapol® LA070, Clariant) [0283] Fatty Acid is a C.sub.12-18 stripped palm kernel fatty acid [0284] SRP1 is a polyester prepared according to Example I [0285] TEA triethanolamine

[0286] Stability Test in Detergent Composition

[0287] A series of exemplary liquid laundry detergent compositions, both excluding and including soil release polymer, were prepared according to Table B. Samples 1 to 4 include sodium hydroxide as the buffering system. Samples 5 to 7 contain triethanolamine as the buffering system. Those compositions containing soil release polymer were subjected to storage tests in order to determine the hydrolytic stability of the polymers.

TABLE-US-00009 TABLE B Liquid laundry detergent compositions for hydrolytic stability testing wt.-% a.m. Ingredient 1 2 3 4 5 6 7 LAS 5.20 5.20 5.20 5.20 5.20 5.20 5.20 SLES 2EO 6.50 6.50 6.50 6.50 6.50 6.50 6.50 NI 7EO 5.20 5.20 5.20 5.20 5.20 5.20 5.20 Fatty Acid 2.80 2.80 2.80 2.80 2.80 2.80 2.80 Glycerol 2.40 2.40 2.40 2.40 2.40 2.40 2.40 Ethanol 1.20 1.20 1.20 1.20 1.20 1.20 1.20 Sodium citrate 1.70 1.70 1.70 1.70 1.70 1.70 1.70 Sodium tetraborate 2.00 2.00 2.00 2.00 2.00 2.00 2.00 decahydrate TexCare ® SRN170 0.00 1.00 0.00 0.00 0.00 1.00 0.00 SRP1 0.00 0.00 1.00 0.00 0.00 0.00 1.00 SRP2 0.00 0.00 0.00 1.00 0.00 0.00 0.00 Demin water and ad 100 ad 100 ad 100 ad 100 — — — NaOH to adjust pH Demin water and — — — — ad 100 ad 100 ad 100 TEA to adjust pH pH Value 8.4  8.4  8.4  8.4  8.4  8.4  8.4  Appearance at clear clear clear clear clear clear clear room temperature

[0288] Key to Ingredients Used: [0289] TexCare® SRN170 is a comparative soil release polymer comprising —OOC-(1,4-phenylene)-COO— structural units and —O—CH.sub.2CH.sub.2—O-structural units, i.e. comprising only repeating structural units (a1) of the polyesters of component a) contained in the inventive liquid laundry detergent compositions, and no repeating structural units (a2) of the polyesters of component a) contained in the inventive liquid laundry detergent compositions [0290] SRP2 is a polyester prepared according to Example III

[0291] Soil Release Test

[0292] The inventive liquid laundry detergent compositions containing the polyesters of component a) and prepared according to the compositions listed in Table B, were tested for their soil release performance according to the “Dirty-Motor Oil” Test (DMO-Test) using a Lini Apparatus. The conditions for the test are listed in Table C.

TABLE-US-00010 TABLE C Washing conditions - Soil Release Test Equipment Linitest Plus (SDL Atlas) Water hardness 14° dH Washing temperature 40° C. Washing time 30 min Detergent concentration 4.3 g/l Soiled Fabric:Liquor Ratio 1:40

[0293] As test fabric, white polyester standard swatches (WFK 30A, from WFK Testgewebe GmbH) were used. The fabrics were prewashed three times with the stored liquid laundry detergent compositions. The swatches were then rinsed, dried and soiled with 25 μl of dirty motor oil. After 1 hour the soiled fabrics were washed again with the same stored liquid laundry detergent compositions used in the pre-washing step. After rinsing and drying the washed swatches, a measurement of the remission of the stained fabric at 457 nm was made using a spectrophotometer (Datacolor 650).

[0294] Based on the remission of the clean unstained swatch, R.sub.c, the stained swatches before washing, R.sub.u, and the washed swatch, R.sub.w, a soil release index (SRI) can be defined:

[00001]$\mathrm{SRI}=\frac{\left(R_w-R_u\right)}{\left(R_c-R_u\right)}\times 100$

[0295] As the soil removal will also depend on the performance of the detergent without polymer, a normalized value, SRI.sub.norm, can be measured by dividing the value for SRI with polymer by the SRI value without polymer. The resulting quantity no longer depends on R.sub.c and hence simplifies the measurement and calculation. The case of no improvement over the base detergent would deliver a value of 1, hence subtracting 1 will reset the baseline to 0, thus:

[00002]${\mathrm{SRI}}_{\mathrm{norm}}=\frac{{\left(R_w-R_u\right)}_{\mathrm{with}.Math..Math.\mathrm{polymer}}}{{\left(R_w-R_u\right)}_{\mathrm{without}.Math..Math.\mathrm{polymer}}}-1$

[0296] The washing results obtained for the stored liquid laundry detergent compositions comprising the soil release polymers are shown in Table D. The values are normalized to the value obtained from a freshly prepared sample of TexCare® SRN170.

[0297] Hydrolysis Determination

[0298] One of the main products from the hydrolysis of soil release polyesters under alkaline conditions is terephthalic acid. The hydrolytic stability was thus monitored by measuring the terephthalic acid content by HPLC.

[0299] HPLC analysis: 10 μl sample was injected onto a Synergi Polar RP column of dimensions 250×4.6 mm with porosity 80 Å and particle size 4 μm. The detection was monitored at 240 nm on a diode array detector. The gradient was made with two eluents. The eluent A was 0.005 mol/I of tetrabutylammonium bisulfate in a 95/5% (v/v) water/acetonitrile mixture. The eluent B was a 5/95% (v/v) water/acetonitrile mixture. Separations were conducted at a flow-rate of 1 ml/min. Quantification was performed by externally calibrating solutions of terephthalic acid in the range 1 to 30 mg/kg.

[0300] The samples were independently fully hydrolysed in order to determine the maximum concentration of free terephthalic acid achievable. This was performed by adding 300 mg of the polymer to a vial with 3 g KOH solution (2 mol/dm.sup.3) and 15 g water and then heating the solution to 130° C. where it was maintained for 1.5 hours. After cooling, the solution was diluted to 1 wt.-% and the terephthalic acid content measured as described via HPLC. The concentrations (measured in mg/kg) were then converted into a percentage of the maximum possible terephthalic acid concentration. The values for the degree of hydrolysis thus calculated are shown in Table D.

[0301] The prepared compositions were stored at 40° C. for 28 days. The hydrolysis of the polyesters was then determined by measuring the concentration of terephthalic acid by HPLC analysis. The values reported in Table D are also shown relative to the value obtained for aged samples of TexCare® SRN170, namely compositions 2 and 6 in Table B.

TABLE-US-00011 TABLE D Stability of compositions prepared according to Table B Degree of Relative degree of SRI.sub.norm Detergent hydrolysis after hydrolysis after SRI.sub.norm composition 28 days at 28 days at 40° C. (TexCare SRN170 from Table B 40° C. [%] [%] fresh) [%] 1 (comparative) — — 0 2 (comparative) 49 100 24 3 (inventive)  9 19 107 4 (inventive) 10 21 78 5 (comparative) — — 0 6 (comparative) 67 100 7 7 (inventive) 19 29 58

[0302] Primary Detergency

[0303] Inventive liquid laundry detergent compositions containing the polyesters of component a) exhibit advantageous soil removal of oily and fatty stains from polyester containing fabrics. Compositions 1 (containing no polymer) and 3 (containing a polyester prepared according to Example 1) from Table B were tested according to the test protocol detailed in Table E. The stained fabrics were used as purchased from the Center for Test Materials, Holland. Color measurements were performed before washing and after one wash cycle and the CIE-L*, a* and b* values noted. The performance was measured by calculating the value of ΔE according to the following formula:

[00003]$\Delta .Math..Math.E=\sqrt{{\left(L_{\mathrm{unwashed}}^{*}-L_{\mathrm{washed}}^{*}\right)}^2+{\left(a_{\mathrm{unwashed}}^{*}-a_{\mathrm{washed}}^{*}\right)}^2+{\left(b_{\mathrm{unwashed}}^{*}-b_{\mathrm{washed}}^{*}\right)}^2}.$

TABLE-US-00012 TABLE E Washing conditions - Primary Detergency Equipment Miele frontloading washing machine, W1935 WPS WTL Water hardness 14° dH Washing temperature 40° C. Washing program Cotton Detergent concentration 4.3 g/l Ballast 3 kg cotton Soil Ballast Load (SBL) 3 SBL towels (from CFT, Holland)

[0304] The results of primary detergency are shown in Table F.

TABLE-US-00013 TABLE F Primary Detergency Results Polyester-Cotton ΔE Polyester ΔE Com- Composition 1 Composition 3 Composition 1 position 3 Stain (comparative) (inventive) (comparative) (inventive) Olive 17 26.9 5.6 13.1 oil with carbon black Pigment/ 16.2 20.7 6.7 19.5 sebum Fluid 24.5 23.9 7.7 20.2 make up Lipstick 30.8 35.4 14.6 27.5 red, diluted