LAUNDRY DETERGENT COMPOSITIONS

Abstract

The invention provides a liquid laundry detergent composition having:

(i) an aqueous continuous phase including from 3 to 80% (by weight based on the total weight of the composition) of one or more detersive surfactants and from 0.05% to 2% (by weight based on the total weight of the composition) of a first polymeric rheology modifier; and
(ii) a dispersed phase of suspended benefit agent delivery particles; the particles having a core-shell structure in which a shell of polymeric material entraps a core containing the benefit agent;
in which a second polymeric rheology modifier comprises a hydrophilic polysaccharide backbone and is covalently attached to the exterior surface of the shell of the delivery particle (either directly or via a linking group);
and in which the first and the second polymeric rheology modifiers each have a hydrophilic backbone including at least one hydrophobic segment which is available to form non-specific hydrophobic associations within the composition.

Claims

1. A liquid laundry detergent composition having: (i) an aqueous continuous phase including from 3 to 80% (by weight based on the total weight of the composition) of one or more detersive surfactants and from 0.05% to 2% (by weight based on the total weight of the composition) of a first polymeric rheology modifier; and (ii) a dispersed phase of suspended benefit agent delivery particles; the particles having a core-shell structure in which a shell of polymeric material entraps a core containing the benefit agent; in which a second polymeric rheology modifier comprises a hydrophilic polysaccharide backbone and is covalently attached to the exterior surface of the shell of the delivery particle (either directly or via a linking group); and in which the first and the second polymeric rheology modifiers each have a hydrophilic backbone including at least one hydrophobic segment so that it/they is/are available to form non-specific hydrophobic associations within the composition wherein the second polymeric rheology modifier has a hydrophilic polysaccharide backbone selected from hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), methylcellulose (MC), hydroxypropylmethylcellulose (HPMC), ethylhydroxyethylcellulose (EHEC), and methylhydroxyethylcellulose (MHEC); and the hydrophilic polysaccharide backbone is selected from HEC having a molar substitution (MS) ranging from 0.5 to 4.0; and EHEC having an MS ranging from 0.5 to 4.0 and a degree of ethyl substitution (DS.sub.ethyl) ranging from 0.3 to 1.2; and in which pendant hydrophobic groups selected from linear C.sub.12-C.sub.16 alkyl groups are attached to the hydrophilic backbone by ether linkages.

2. A composition according to claim 1, in which the first polymeric rheology modifier has an acrylic copolymer backbone prepared by the addition polymerization of a mixture of ethylenically unsaturated monomers, in which hydrophilic character is provided by the inclusion of anionic or anionisable monomers.

3. A composition according to claim 2, in which the first polymeric rheology modifiers is a HASE polymer selected from linear or crosslinked copolymers that are prepared by the polymerization of a monomer mixture comprising (i) from 35 to 65% (by weight based on the total weight of the monomer mixture) of nonionic monomers; (ii) from 35 to 65% (by weight based on the total weight of the monomer mixture) of anionic or anionisable monomers; (iii) from 1 to 25% (by weight based on the total weight of the monomer mixture) of hydrophobic monomers having an ethylenically unsaturated section (for addition polymerization with the other monomers in the mixture) and a hydrophobic section, and (iv) optionally, from 0.01 to 0.1% (by weight based on the total weight of the monomer mixture) of polyethylenically unsaturated copolymerizable monomers effective for crosslinking.

4. A composition according to claim 3, in which the nonionic monomers (i) are selected from ethyl acrylate, methyl acrylate, and butyl acrylate; the anionic or anionisable monomers (ii) are selected from acrylic acid and methacrylic acid, and the hydrophobic monomers (iii) are selected from C.sub.8-C.sub.30 alkylated polyethoxylated (meth) acrylates in which the polyethoxylated portion comprises from 15 to 60 ethylene oxide (EO) units.

5. A composition according to claim 1, in which the benefit agent is a fragrance formulation and the fragrance formulation comprises from 20 to 40% by weight based on the total weight of the benefit agent delivery particle.

6. A composition according to claim 1, in which the shell of polymeric material is an aminoplast shell formed from the polycondensation product of melamine with formaldehyde.

7.-9. (canceled)

10. A composition according to claim 1 which is essentially free of additional structuring agents selected from fibre-based structuring agents and/or crystalline structuring agents.

Description

EXAMPLES

Example 1: Attachment of a HM-Polysaccharide onto Perfume Encapsulates Via Melamine-Formaldehyde (MF) Shell Formation

[0141] The pre-formed melamine formaldehyde perfume encapsulates were 5 micron in size and obtained from International Flavours and Fragrances (IFF) Limited. The particle solids were 37.2 wt % and perfume solids were 28 wt % respectively. The HM-polysaccharides utilized were:

[0142] Natrosol® Plus 330: cetyl modified hydroxyethylcellulose (HM-HEC) from Ashland

[0143] PolySurf® 67: cetyl modified hydroxyethylcellulose (HM-HEC) from Ashland

[0144] Bermocoll® EHM200, EHM300 and EHM500: (C.sub.12-C.sub.16)-modified ethyl hydroxyethyl cellulose (HM-EHEC) from Akzo Nobel.

[0145] The following procedure outlines the synthetic modification to attach the HM-polysaccharide to the surface via the formation of additional melamine formaldehyde (MF) shell:

[0146] 1. Pre-Polymer Preparation

[0147] To a 100 ml conical flask was add 19.5 g formalin (37 wt % aqueous formaldehyde) and 44 g water. The pH of the solution was adjusted to 8.9 using 0.7 g of 5 wt % aqueous sodium carbonate. 10 g of melamine and 0.64 g of sodium chloride was added, and the mixture stirred for 10 minutes at room temperature. The mixture was heated to 62° C. and stirred until it became clear. This mixture is referred to as “pre-polymer(1)”.

[0148] 2. HM-Polysaccharide Attachment to Pre-Formed Melamine Formaldehyde Perfume Encapsulates:

[0149] 0.2 g of PolySurf® 67 was dissolved in 74.7 g deionized water by shaking overnight on an orbital shaker and then transferred to a 250 ml round bottomed flask fitted with overhead stirrer and condenser. 25.3 g of melamine formaldehyde encapsulate slurry (37.7 wt % particle solids) was added and the mixture heated to 75° C. with stirring. 0.9 g of a freshly prepared pre-polymer(1) solution was added and the pH adjusted to 4.1, using 2 g of 10 wt % formic acid aqueous solution. The mixture was then left to stir, at 75° C. for 2 hours. The solution was then adjusted to pH 7 using 7.5 g of 5 wt % sodium carbonate aqueous solution. A final dispersion (100 g) consisting of 10 wt % encapsulate solids containing an additional 2 wt % melamine formaldehyde shell and 2 wt % (based on final particle weight) of PolySurf® 67 was obtained.

Example 2: Attachment of a HASE Polymer onto Perfume Encapsulates Via Melamine-Formaldehyde Shell Formation

[0150] The process described in Example 1 was followed, with xyloglucan (Glyloid 3S from DSP Gokyo Food & Chemical) substituted for the PolySurf® 67. On completion, 0.67 g of CrystaSense Sapphire (HASE polymer from Croda) was added, along with 0.027 g EDAC. The solution was then shaken for 4 hours at room temperature.

Example 3: Preparation of a Laundry Detergent Containing a HASE-Rheology Modifier and Modified Capsule

[0151] Liquid laundry detergent formulations were prepared by sequential mixing of the ingredients as shown in Table 1. Example A is a comparative example (not according to the invention) and Examples 1 to 4 are examples according to the invention.

TABLE-US-00001 TABLE 1 Example A 1 2 3 4 Ingredient wt. % (active ingredient) NaOH 0.22 0.22 0.22 0.22 0.22 TEA 4.50 4.50 4.50 4.50 4.50 Citric Acid 0.18 0.18 0.18 0.18 0.18 LAS acid 2.00 2.00 2.00 2.00 2.00 EPEI 0.75 0.75 0.75 0.75 0.75 SRP 0.10 0.10 0.10 0.10 0.10 SLES 3EO 6.00 6.00 6.00 6.00 6.00 BIT 0.02 0.02 0.02 0.02 0.02 MIT 0.01 0.01 0.01 0.01 0.01 Acusol ® Millennium 1.10 1.10 1.10 1.10 1.10 Microcapsule.sup.(1) 0.60 — — — — Microcapsule.sup.(2) — 0.60 — — — Microcapsule.sup.(3) — — 0.60 — — Microcapsule.sup.(4) — — — 0.60 — Microcapsule.sup.(5) — — — — 0.60 Demineralised water q.s. to 100 .sup.(1)13.5-micron diameter core-shell microcapsules with melamine-formaldehyde shell .sup.(2)13.5-micron diameter core-shell microcapsules with melamine-formaldehyde shell; exterior shell surface modified with 2.0% (by weight based on total weight of microcapsule) PolySurf ® 67 .sup.(3)13.0-micron diameter core-shell microcapsules with melamine-formaldehyde shell; exterior shell surface modified with 2.0% (by weight based on total weight of microcapsule) Bermocoll ® EHM200 .sup.(4)13.2-micron diameter core-shell microcapsules with melamine-formaldehyde shell; exterior shell surface modified with 2.0% (by weight based on total weight of microcapsule) Bermocoll ® EHM300 .sup.(5)16.5-micron diameter core-shell microcapsules with melamine-formaldehyde shell; exterior shell surface modified with 2.0% (by weight based on total weight of microcapsule) Bermocoll ® EHM500

[0152] Samples of the above formulations were evaluated for stability using a LUMiSizer (LUM GmbH) dispersion analyser. The LUMiSizer is an analytical centrifuge that instantaneously measures the extinction (space- and time-resolved) of the transmitted light across the entire length of a sample using the STEP-Technology. Using an enhanced optical system, the LUMiSizer can analyse particle and droplet velocity distributions for creaming and sedimentation. By varying the speed and temperature, the creaming process can be accelerated and quantified.

[0153] The stability of a sample is expressed as an instability index (II), where 1 represents complete instability and 0 indicates complete stability.

[0154] All samples were tested using the following protocol: 8 hours at 37° C., 829 rpm (equivalent to 100×G). Sample tube—2 mm path length polycarbonate.

[0155] Sample formulations were prepared and rolled for 12 hours prior to measurement.

[0156] Results

[0157] The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Example Example Example Example Example Formulation A 1 2 3 4 Instability Index 0.336 0.185 0.016 0.011 0.016

[0158] It can be seen from a comparison of Examples 1 to 4 with Example A that modification of the exterior shell surface of the microcapsule with HM-polysaccharides imparts improved stability in formulations which are thickened with a hydrophobically-modified rheology modifier.