Laundry detergents containing soil release polymers

Abstract

The invention relates to liquid laundry detergent compositions comprising a) one or more polyesters comprising two or more of the repeating structural unit (a1), one or more of the repeating structural unit (a2) and either one or two of the terminal group (a3), wherein G.sup.1 is one or more of (OC.sub.nH.sub.2n) with n being a number of from 2 to 10, R.sup.1 is a C.sub.1-30 alkyl, 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 0 to 50, whereby the (OC.sub.3H.sub.6) and (OC.sub.2H.sub.4) groups of the terminal group (a3) may be arranged blockwise, alternating, periodically and/or statistically and wherein the connections of the groups (OC.sub.3H.sub.6) and (OC.sub.2H.sub.4) to R.sup.1 and NH are free to vary, adjacent structural units (a1) are connected by the structural unit (a2), in the case that only one terminal group (a3) is present in the polymer, the other terminal group is selected from the group consisting of OH, OCH.sub.3, and G.sup.1OH, and both terminal groups may only be linked to the structural unit (a1), and b) one or more surfactants. The one or more polyesters of component a) possess advantageous stability in alkaline environments, beneficial solubility and advantageously are clearly soluble in alkaline compositions such as liquid laundry detergent compositions and also possess advantageous soil release properties on fatty and oily stains. ##STR00001##

Claims

1. A liquid laundry detergent composition comprising a) 0.1 wt.-% to 10 wt.-%, based on the total weight of the liquid laundry detergent composition, of at least one polyester having an average molecular weight (M.sub.w) from 2,000 to 20,000 g/mol and comprising at least two of the repeating structural unit (a1), at least one of the repeating structural unit (a2) and either one or two of the terminal group (a3) ##STR00011## wherein G.sup.1 is at least one of (OC.sub.2H.sub.4), (OC.sub.3H.sub.6) or (OC.sub.4H.sub.8), R.sup.1 is a C.sub.1-4 alkyl, 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 0 to 30, whereby the (OC.sub.3H.sub.6)- and (OC.sub.2H.sub.4)-groups of the terminal group (a3) may be arranged blockwise, alternating, periodically and/or statistically, and wherein the connections of the groups (OC.sub.3H.sub.6) and (OC.sub.2H.sub.4) to R.sup.1 and NH are free to vary, adjacent structural units (a1) are connected by the structural unit (a2), in the case that only one terminal group (a3) is present in the polymer, the other terminal group is selected from the group consisting of OH, OCH.sub.3, and G.sup.1OH, and both terminal groups may only be linked to the structural unit (a1), wherein the total amount of repeating structural units (a1) and (a2) and of the terminal group (a3) in the one or more polyesters of component a), based on the total weight of the one or more polyesters of component a), is at least 50 wt.-%, and b) 5 wt.-% to 65 wt.-%, based on the total weight of the liquid laundry detergent composition, of one or more surfactants.

2. The liquid laundry detergent composition according to claim 1, wherein R.sup.1 is CH.sub.3.

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 110.

4. The liquid laundry detergent composition according to claim 1, wherein the at least one polyester of component a) additionally comprise one or more of the repeating structural unit (a4), which may be indirectly linked to repeating structural units (a1) or other repeating structural units (a4) via the repeating structural unit (a2), or directly linked to a terminal group: ##STR00012## wherein 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 one or more polyesters of component a) is from 2 to 60.

6. The liquid laundry detergent composition according to claim 1, wherein the total amount of repeating structural units (a1) and (a2) and of the terminal group (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 70 wt.-%.

7. The liquid laundry detergent composition according to claim 4, wherein the amount of repeating structural unit (a4) 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.-%.

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

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

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

11. The liquid laundry detergent composition according to claim 10, 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.

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

Description

EXAMPLES

(1) 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.-%).

(2) Polymer Preparation

(3) 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.

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

(5) The following abbreviations and materials are used: 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 DMT Dimethylterephthalate PG 1,2-propylene glycol TIP titanium isopropoxide NaOAc sodium acetate a.m. active matter
General Procedure for the Preparation of the Polyesters

(6) The polyester synthesis is carried out in a three-step procedure by the reaction of dimethyl terephthalate (DMT), one or more alkylene glycols, preferably 1,2-propylene glycol (PG), alkyl capped polyalkylene glycol and optionally additional monomers IV), using sodium acetate (NaOAc) and titanium isopropoxide (TIP) as the catalyst system.

(7) Precursor Synthesis

(8) The DMT and alkyl capped polyalkylene glycol are weighed into a five neck round-bottom flask with a quantity of methanol and the contents heated while stirring to reflux. Sodium methoxide is then slowly added and the contents of the flask stirred for 15 hours under reflux conditions. The reaction mixture is then neutralized with a suitable acid, e.g. HCl or H.sub.2SO.sub.4 and the solvent evaporated.

(9) Transesterification

(10) The alkylene glycol and a catalytic amount of NaOAc are then added to the flask and the mixture 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 from 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.

(11) Polycondensation

(12) 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 20 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

(13) TABLE-US-00001 Amount Raw Material [Abbreviation] 101.95 g DMT 336 g Endcap 1 270 ml Methanol 80 g PG 0.5 g NaOAc 0.2 g TIP

(14) Liquid laundry detergent compositions containing exemplary polyester A series of exemplary liquid laundry detergent compositions, both excluding and including soil release polymer, were prepared according to Table A. Samples 1 to 3 include sodium hydroxide as the buffering system. Samples 4 to 6 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.

(15) Key to ingredients used in the compositions of Table A LAS is C.sub.12-14 linear alkylbenzene sulfonate, sodium salt SLES 2EO is sodium lauryl ether sulfate with 2 moles EO (Genapol LRO, Clariant). NI 7EO is C.sub.12-15 alcohol ethoxylate 7EO nonionic (Genapol LA070, Clariant) Fatty Acid is a C.sub.12-18 stripped palm kernel fatty acid TEA triethanolamine SRP1 is a polyester prepared according to Example I TexCare SRN170 is a comparative soil release polymer comprising OOC-(1,4-phenylene)-COO structural units and OCH.sub.2CH.sub.2O-structural units, i.e. comprising repeating structural units (a1) and (a2) of the polyesters of component a) contained in the inventive liquid laundry detergent compositions, and no terminal groups (a3) of the polyesters of component a) contained in the inventive liquid laundry detergent compositions

(16) TABLE-US-00002 TABLE A Liquid laundry detergent compositions for hydrolytic stability testing wt.-% a.m. Ingredient 1 2 3 4 5 6 LAS 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 NI 7EO 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 Glycerol 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 Sodium citrate 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 decahydrate TexCare SRN170 0.00 1.00 0.00 0.00 1.00 0.00 SRP1 0.00 0.00 1.00 0.00 0.00 1.00 Demin water and ad ad ad 100 NaOH to 100 100 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 Appearance at room clear clear clear clear clear clear temperature
Soil Release Test

(17) The inventive liquid laundry detergent compositions containing the polyesters of component a) and prepared according to the compositions listed in Table A, 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 B.

(18) TABLE-US-00003 TABLE B 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

(19) 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 l 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).

(20) 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:

(21) $\mathrm{SRI}=\frac{\left(R_w-R_u\right)}{\left(R_c-R_u\right)}100$

(22) 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 will deliver a value of 1, hence subtracting 1 will reset the baseline to 0, thus:

(23) ${\mathrm{SRI}}_{\mathrm{norm}}=\frac{{\left(R_w-R_u\right)}_{\mathrm{with}\mathrm{polymer}}}{{\left(R_w-R_u\right)}_{\mathrm{without}\mathrm{polymer}}}-1$

(24) The washing results obtained for the stored liquid laundry detergent compositions comprising the soil release polymers are shown in Table C. The values are normalized to the value obtained from a freshly prepared sample of TexCare SRN170.

(25) Hydrolysis Determination

(26) 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.

(27) HPLC analysis: 10 l sample was injected onto a Synergi Polar RP column of dimensions 2504.6 mm with porosity 80 and particle size 4 m. 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/l 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.

(28) 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 C.

(29) 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 C are also shown relative to the value obtained for aged samples of TexCare SRN170, namely samples 2 and 5 in Table A.

(30) TABLE-US-00004 TABLE C Stability of compositions prepared according to Table A Detergent composition from Table B Degree of hydrolysis after 28 days at 40 C. [%] Relative degree of hydrolysis after 28 days at 40 C. [%] $\frac{{\mathrm{SRI}}_{\mathrm{norm}}}{\begin{array}{c}{\mathrm{SRI}}_{\mathrm{norm}}\\ \left(\mathrm{TexCare}\mathrm{SRN170}\mathrm{fresh}\right)\\ \left[\%\right]\end{array}}$ 1 (comparative) 0 2 (comparative) 49 100 25 3 (inventive) 10 20 93 4 (comparative) 0 5 (comparative) 67 100 7 6 (inventive) 18 27 60