EP0862609B1

EP0862609B1 - Laundry detergent composition

Info

Publication number: EP0862609B1
Application number: EP96932507A
Authority: EP
Inventors: Abid Nadim Khan-Lodhi; Christopher Whaley
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1995-10-04
Filing date: 1996-09-11
Publication date: 2000-07-12
Anticipated expiration: 2016-09-11
Also published as: AU724175B2; HUP9900093A2; CZ289267B6; DE69609346D1; WO1997012952A1; ZA967834B; AU7128496A; GB9520519D0; BR9610791A; AR003768A1; CZ101398A3; HUP9900093A3; DE69609346T2; PL188709B1; PL326004A1; EP0862609A1

Description

Technical Field

The present invention relates to detergent compositions. In particular the invention relates to detergent compositions that have excellent detergency properties and also soften fabrics.

Background and Prior Art

With some fabrics, especially of natural origin repeated washing can lead to fabric harshness, giving the fabrics an unpleasant feel. For some years, fabric conditioning products have been available, intended inter alia for alleviating this fabric harshness by softening the fabrics in a post-washing step, for example in the rinse step of a fabric laundering process. There has been a desire to provide a single detergent composition which would be capable of both washing and softening the fabrics to overcome the inconvenience of using separate products.
According to British Patent GB 1 400 898 (Procter and Gamble/STORM) a possible solution to this problem is to include in the detergent composition a smectite clay containing material having a cation exchange capacity of at least 50 meq/100g, together with a detergent active material.
While some success has been obtained with the use of such clay materials, softening performance still does not generally match that obtained by the use of separate products and there is therefore scope for improving performance.
WO95/27769 (Unilever) and WO/95/27771 (Unilever) disclose fabric conditioning compositions in which the cationic softener is combined with a nonionic or amphoteric surfactant such that when diluted 70 wt% of the fabric softening compound is in solution.
WO 95/0443 discloses aqueous fabric conditioning compositions which contain a quaternary ammonium compound, a cellulose and optionally a non-ionic surfactant. The compositions exhibit a solubility of the cationic fabric softener of less than 70% when diluted to a total active of 5 wt%.
WO 94/06899 discloses detergent mixtures containing oligoglycosides and esterquats which are useful for preparing surfactants and for tertiary oil extraction.
We have surprisingly found that a novel detergent composition can be formed which gives excellent softening properties and also excellent detergency.

Definition of the Invention

Thus according to one aspect of the invention there is provided a fabric softening detergent composition comprising
(i) a detergent surfactant comprising an amphoteric surfactant and/or a nonionic surfactant;
(ii) a substantially water insoluble fabric softening compound having a solubility not exceeding 1 x 10^-3 wt% in demineralized water at 20°C and comprising a compound having two C_12-22 alkyl or alkenyl groups connected to a quaternary ammonium head group via at least one ester link or a quaternary ammonium compound comprising of a single chain with an average chain length equal to or greater than C₂₀;
(iii)a detergency booster;
A further aspect of the invention provides the use of self-size-limiting molecular aggregates (as defined below) as a fabric softening system in a detergent composition.

Detailed Description of the Invention

Without wishing to be bound by theory it is believed that the fabric softening system within the detergent composition of the invention is not in conventional lamellar form, and when contacted with water may be solubilised partially in the form of self-size-limiting molecular aggregates, such as micelles or micellar solutions with solid or liquid interiors or mixtures thereof. Where the composition is in a form containing water the composition itself may be at least partially in the form of self-size-limiting molecular aggregates. It is thought that it is this new structure of the fabric softening system within the detergent composition that overcomes the problems of the prior art.
In addition to the detergent surfactant and fabric softening compound the composition may contain a non-surfactant solubiliser for the fabric softening compound, preferably the non-surfactant solubiliser is not a volatile solvent.
Suitably the fabric softening compound and detergent surfactant form a transparent mix when in liquid form. However addition of further detergent ingredients may cause the composition to become cloudy. The following tests may be used to determine definitely whether or not a composition falls within the present invention.

Test I

a) The fabric softening compound and the detergent surfactant and any non-surfactant solubiliser are diluted with water at a concentration of 5 wt% (of the fabric softening compound and the detergent surfactant). The diluate is warmed to between 60-80°C then cooled to room temperature and stirred for 1 hour to ensure equilibration. A first portion of the resulting test liquor is taken and any material which is not soluble in the aqueous phase is separated by sedimentation or filtration until a clear aqueous layer is obtained. (Ultracentrifuges or ultrafilters can be used for this task.) The filtration may be performed by passing through successive membrane filters of 1 µm, 0.45 µm and 0.2 µm.
b) The concentration of the fabric softening compound in the clear layer is measured by titrating with standard anionic surfactant (sodium dodecyl sulphate) using dimidiumsulphide disulphine blue indicator in a two-phase titration with chloroform as extracting solvent.
c) The titration with anionic surfactant is repeated with a second portion of fabric softening composition which has been diluted but not separated.
d) Comparison of b) with c) should show that the concentration of fabric softening compound in b) is at least 70 wt% (preferably 80 wt%) of the concentration of fabric softening compound in c). This demonstrates that the fabric softening compound was in solution.

Test II

a) The fabric softening compound, detergent surfactant and any non-surfactant solubiliser are diluted as for Test I.
b) The viscosity of the diluate at a shear rate of 110s-1 is measured.
c) The diluate is warmed to 60°C and held at this temperature for 1 day.
d) The diluate is cooled to 20°C and the viscosity is once again measured at a shear rate of 110s-1.
e) Comparison between the viscosities of b) and c) should show that they differ by less 5 mPas.
It is preferable if the detergent compositions of the invention conform to the following test:

Test III

a) The fabric softening compound, detergent surfactant and any non-surfactant solubiliser are diluted as for Test I.
b) The viscosity of the diluate at a shear rate of 110s-1 is measured.
c) The diluate is frozen and thawed.
d) The viscosity is once again measured at a shear rate of 110s-1.
e) Comparison between the viscosities of b) and c) should show that they differ by less than 10 mPaS.
If liquid the detergent compositions according to the invention may be translucent. Translucent in the context of this invention means that when a cell 1cm in depth is filled with the fabric softening composition, "Courier 12 point" typeface can be read through the cell.
A further advantage of the present invention is that the softening of the composition is enhanced over detergent compositions of the prior art comprising similar levels of fabric softening compound.

The Detergent Surfactant

The detergent surfactant may be nonionic or amphoteric.
If the detergent surfactant is a nonionic surfactant it may be characterised in terms of its phase behaviour. Suitable nonionic surfactants are those for which when contacted with water, the first lyotropic liquid crystalline phase formed is normal cubic (I1) or normal cubic-bicontinuous (V1) or hexagonal (H1) or nematic (Ne1), or intermediate (Int1) phase as defined in the article by G J T Tiddy et al, J Chem Soc. Faraday Trans. 1., 79, 975, 1983 and G J T Tiddy , "Modern Trends of Colloid Science in Chemistry and Biology", Ed. H-F Eicke, 1985 Birkhauser Verlag Basel]. Surfactants forming Lα phases at concentrations of less than 20 wt% are not suitable.
For the purposes of this invention nonionic surfactants may be defined as substances with molecular structures consisting of a hydrophilic and hydrophobic part. The hydrophobic part consists of a hydrocarbon and the hydrophilic part of strongly polar groups. The nonionic surfactants of this invention are soluble in water.
The most preferred nonionic surfactants are alkoxylated, preferably ethoxylated compounds and carbohydrate compounds.
Examples of suitable ethoxylated surfactants include ethoxylated alcohols, ethoxylated alkyl phenols, ethoxylated fatty amides and ethoxylated fatty esters.
Preferred nonionic ethoxylated surfactants have an HLB of from about 10 to about 20. It is advantageous if the surfactant alkyl group contains an average of at least 12 carbon atoms.
Examples of other suitable nonionic types are carbohydrate surfactants or other polyhydroxy surfactants include alkyl polyglycosides as disclosed in EP 199 765 (Henkel) and EP 238 638 (Henkel), poly hydroxy amides as disclosed in WO 93 18125 (Procter and Gamble) and WO 92/06161 (Procter and Gamble), fatty acid sugar esters (sucrose esters), sorbitan ester ethoxylates, and poly glycerol esters and alkyl lactobionamides.
Excellent softening is achieved if mixtures of carbohydrate based nonionic surfactants and long chain ethoxylate based nonionic surfactants are used. Preferably the ratio of carbohydrate compounds to long chain alcohol ethoxylate is from 3:1 to 1:3, more preferably from 1:2 to 2:1, most preferably approximately at a ratio of 1:1.
Alternatively the detergent surfactant agent may be amphoteric or zwitterionic which are characterised in terms of its phase behaviour. Suitable detergent surfactants are amphoteric surfactants for which, when contacted within water, the first lyotropic liquid crystalline phase formed is normal cubic (I1) or normal cubic-bicontinuous (V1) or hexagonal (H1) or nematic (Nel), or intermediate (Int1) phase as defined in the article by G J T Tiddy et al, J Chem Soc. Faraday Trans. 1., 79, 975, 1983 and G J T Tiddy , "Modern Trends of Colloid Science in Chemistry and Biology", Ed. H-F Eicke, 1985 Birkhauser Verlag Basel]. Surfactants forming Lα phases at concentrations of less than 20 wt% are not suitable.
In the context of this invention amphoteric surfactants are defined as substances with molecular structures consisting of a hydrophilic and hydrophobic part. The hydrophobic part consists of a hydrocarbon and the hydrophilic part consists of both a positive and a negative group. Preferred amphoteric/zwitterionic surfactants include amine oxides, betaines including sulphobetaines and tegobetaines, phosphine oxides and sulphoxides.
Mixtures of detergent surfactants may be used.
For compositions in solid form, especially powder, the detergent surfactant is advantageously solid at room temperature as this provides crisp composition particles.
It is preferable if the detergent surfactant comprises at least 10 wt% of the total composition.

The Fabric Softening Compound

The fabric softening compound is suitably a water insoluble quaternary ammonium material comprising a single alkyl or alkenyl chain length equal to or greater than C₂₀ or, more preferably, the softening compound comprises a quaternary ammonium material having two C_12-22 alkyl or alkenyl groups connected to the quaternary ammonium head group via at least one ester link.
Preferably the fabric softening compound has two long chain alkyl or alkenyl chains with an average chain length equal to or greater than C₁₄. More preferably each chain has an average chain length equal or greater than C₁₆. Most preferably at least 50% of each long chain alkyl or alkenyl group has a chain length of C₁₈.
It is preferred if the long chain alkyl or alkenyl groups of the fabric softening compound are predominantly linear.
The fabric softening compounds used in the compositions of the invention are molecules which provide excellent softening, characterised by chain melting -Lβ to Lα - transition temperature greater than 25°C, preferably greater than 35°C, most preferably greater than 45°C. This Lβ to Lα transition can be measured by DSC as defined in "Handbook of Lipid Bilayers, D Marsh, CRC Press, Boca Raton Florida, 1990 (Pages 137 and 337).
Substantially insoluble fabric softening compounds in the context of this invention are defined as fabric softening compounds having a solubility less than 1 x 10^-3 wt% in demineralised water at 20°C. Preferably the fabric softening compounds have a solubility less than 1 x 10^-4 Most preferably the fabric softening compounds have a solubility at 20°C in demineralised water from 1 x 10^-8 to 1 x 10^-6.
It is especially preferred if the fabric softening compound is a water insoluble quaternary ammonium material which comprises a compound having two C_12-18 alkyl or alkenyl groups connected to the molecule via at least one an ester link. It is more preferred if the quaternary ammonium material has two ester links present. The especially preferred ester-linked quaternary ammonium material for use in the invention can be represented by the formula:
wherein each R¹ group is independently selected from C_1-4 alkyl, hydroxyalkyl or C₂₄ alkenyl groups; and wherein each R² group is independently selected from C_12-22 alkyl or alkenyl groups;
T is
or
X^- is any suitable anion and n is an integer from 0-5.
Di(tallowoyloxyethyl)dimethyl ammonium chloride, available from Hoechst, is especially preferred.
A second preferred type of quaternary ammonium material can be represented by the formula:
wherein R¹, n, X^- and R² are as defined above.
It is advantageous for environmental reasons if the quaternary ammonium material is biologically degradable.
Preferred materials of this class such as 1,2 bis[hardened tallowoyloxy]-3- trimethylammonium propane chloride and their method of preparation are, for example, described in US 4 137 180 (Lever Brothers). Preferably these materials comprise small amounts of the corresponding monoester as described in US 4 137 180 for example 1-hardened tallowoyloxy -2-hydroxy -3-trimethylammonium propane chloride.

The non-surfactant solubiliser

It is particularly advantageous if the compositions of the invention further comprise a non-surfactant solubiliser. Preferred solubilisers include propylene glycol, urea , acid amides up to and including chain lengths of C_6, citric acid and other poly carboxylic acids as disclosed in EP 0 404 471 (Unilever), glycerol, sorbitol and sucrose. Particularly preferred are polyethylene glycols (PEG) having a molecular weight ranging from 200 - 6000, most preferably from 1000 to 2000.
It is preferred if the weight ratio of solubiliser to detergent surfactant is from 2:1 to 1:40. Preferably the ratio of solubiliser to detergent surfactant is not greater than 1:1, more preferably not greater than 1:5.
It is advantageous if the weight ratio of detergent surfactant or the weight ratio of detergent surfactant plus any solubiliser to fabric softening compound is at least 1:1, preferably at least 2:1, more preferably equal to or greater than 5:1. It is advantageous if the ratio of detergent surfactant or detergent surfactant plus any solubiliser to fabric softening compound is equal to or below 50:1, more preferably below 30:1, most preferably 15:1 or below.

Detergency Booster

The detergency booster is defined as any non-surfactant material that aids the detergent composition in removing soil from a fabric.
Typical detergency boosters include soil release and antiredeposition polymers, sequestrants and chelates, builders, enzymes and bleach systems.
If the detergency booster is a detergency builder, it is suitably present in an amount of from 5 to 80 wt%, preferably from 20 to 80 wt%. This may be any material capable of reducing the level of free calcium ions in the wash liquor and will preferably provide the compositions with other beneficial properties such as the generation of an alkaline pH and the suspension of soil removed from the fabric.
Preferred builders include alkali metal (preferably sodium) aluminosilicates, which may suitably be incorporated in amounts of from 5 to 80% by weight (anhydrous basis) of the composition, and may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8-1.5 Na₂O.A1₂O₃.0.8-6 SiO₂
These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 SiO₂ units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature.
Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1 429 143 (Procter & Gamble). The preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof. Also of interest is the novel zeolite P described and claimed in EP 384070 (Unilever).
Phosphate-built detergent compositions are also within the scope of the invention. Examples of phosphorus-containing inorganic detergency builders include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, orthophosphates and hexametaphosphates.
Other builders may also be included in the detergent composition of the invention if necessary or desired: suitable organic or inorganic water-soluble or water-insoluble builders will readily suggest themselves to the skilled detergent formulator. Inorganic builders that may be present include alkali metal (generally sodium) carbonate; while organic builders include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di- and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates; and organic precipitant builders such as alkyl- and alkenylmalonates and succinates, and sulphonated fatty acid salts.
Especially preferred supplementary builders are polycarboxylate polymers, more especially polyacrylates and acrylic/maleic copolymers, suitably used in amounts of from 0.1 to 15 wt%, especially from 0.5 to 10 wt%; and monomeric polycarboxylates, more especially citric acid and its salts, suitably used in amounts of from 0.5 to 20 wt%, more preferably from 5 to 15 wt%.
If the detergency booster according to the invention is a bleach system, this preferably comprises one or more peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, which may be employed in conjunction with activators to improve bleaching action at low wash temperatures.
Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate, advantageously employed together with an activator. Bleach activators, also referred to as bleach precursors, have been widely disclosed in the art. Preferred examples include peracetic acid precursors, for example, tetraacetylethylene diamine (TAED), now in widespread commercial use in conjunction with sodium perborate; and perbenzoic acid precursors; for example sodium nonoyloxy benzene sulphonate (SNOBS), and sodium percarbonate. The novel quaternary ammonium and phosphonium bleach activators disclosed in US 4 751 015 and US 4 818 426 (Lever Brothers Company) are also of great interest. The bleach system may also include a bleach stabiliser (heavy metal sequestrant) such as ethylenediamine tetramethylene phosphonate and diethylenetriamine pentamethylene phosphonate. The skilled detergent worker will have no difficulty in applying the normal principles of formulation to choose a suitable bleach system.
Organic peroxyacids are also suitable detergency boosters. Such materials are illustrated by those disclosed in US 4 374 035, US 4 681 592, US 4 634 551, US 4 686 063, US 4 606 838, and US 4 671 891,(all Procter and Gamble). It is preferred if the organic peroxyacids are cationic, suitable peroxyacids are described in WO94/21605 (Unilever) and WO 94/01399 (Unilever).
Specific examples of preferred peroxyacids for this invention include diperoxydodecanedioic acid (DPDA), nonylamide of peroxy-succinic acid (NAPSA), nonylamide of peroxyadipic acid (NAPAA) decyldiperoxysuccinic acid (DDPSA), 6-N-phthalimido peroxy hexonoic acid (PAP), di N,N'-tere phthaloyldi 16-amino caproic acid (TOCAP) and imidoperoxy mellitic acid (BIPTA).
Preferably the peroxyacid bleach is used at a level which provides an amount of available oxygen (AvO) from 0.1% to 10%, preferably from 0.5% to 5%, and most preferably from 1% to 4%, all by weight of the composition.
The detergency booster may also be one of the detergency enzymes well-known in the art for their ability to degrade and aid in the removal of various soils and stains. Suitable enzymes include the various proteases, cellulases, lipases, amylases, and mixtures thereof, which are designed to remove a variety of soils and stains from fabrics. Examples of suitable proteases are Maxatase (Trade Mark), as supplied by Gist-Brocades N.V., Delft, Holland, and Alcalase (Trade Mark), Esperase (Trade Mark) and Savinase (Trade Mark), as supplied by Novo Industri A/S, Copenhagen, Denmark. Detergency enzymes are commonly employed in the form of granules or marumes, optionally with a protective coating, in amounts of from about 0.1% to about 3.0% by weight of the composition.
It is preferred if the detergency booster is a soil release agent. It is advantageous if the soil release polymer is included in the formulation at levels from 0.1% to 10%, preferably 0.2% to 5%, of a soil release agent. Preferably, such a soil release agent of the present composition is a polymer. Polymeric soil release agents useful in the present invention include hydroxyether cellulosic polymers, copolymeric blocks of terephthalate and polyethylene oxide or polypropylene oxide, and cationic guar gums, and the like.
The cellulosic derivatives that are functional as soil release agents may be characterised as certain hydroxyethers of cellulose such as Methocel® (Dow); also, certain cationic cellulose ether derivatives such as Polymer JR-125^R, JR-400^R, and JR-30M^R (Union Carbide).
Other effective soil release agents are cationic guar gums such as Jaguar Plus^R (Stein Hall) and Gendrive 458^R (General Mills).
A preferred detergent composition has a polymeric soil release agent selected from the group consisting of methyl cellulose, hydroxypropyl methylcellulose, or hydroxybutyl methylcellulose, said cellulosic polymer having a viscosity in 2% aqueous solution at 20°C of 15.10³ to 75 Pa.s (15 to 75,000 centipoise).
A more preferred soil release agent is a copolymer having blocks of terephthalate and polyethylene oxide. More specifically, these polymers are comprised of repeating units of ethylene terephthalate and polyethylene oxide terephthalate at a molar ratio of ethylene terephthalate units to polyethylene oxide terephthalate units of from 25:75 to 35:65, said polyethylene oxide terephthalate containing polyethylene oxide blocks having molecular weight of from 300 to 2000. The molecular weight of this polymeric soil release agent is in the range of from 5,000 to 55,000.
Another preferred polymeric soil release agent is a crystallisable polyester with repeat units of ethylene terephthalate units containing 10-15% by weight of ethylene terephthalate units together with 90-50% by weight of polyoxyethylene terephthalate units, derived from a polyoxyethylene glycol of average molecular weight 300-6,000, and the molar ratio of ethylene terephthalate units to polyoxyethylene terephthalate units in the crystallizable polymeric compound is between 2:1 and 6:1. Examples of this polymer include the commercially available material Zelcon^R 4780 (from Dupont) and Milease^RT (from ICI).
Highly preferred soil release agents are polymers of the generic formula:
in which X can be any suitable capping group, with each X being selected from the group consisting of H, and alkyl or acyl groups containing from 1 to about 4 carbon atoms. n is selected for water solubility and generally is from 6 to 113, preferably from 10 to 50. u is critical to formulation in a liquid composition having a relatively high ionic strength. There should be very little material in which u is greater than 10. Furthermore there should be at least 20%, preferably at least 40% of material in which u ranges from 3 to 5.
The R¹ moieties are essentially 1,4-phenylene moieties. As used herein, the term "the R¹ moieties consist entirely of 1,4- phenylene moieties, or are partially substituted with other arylene or alkarylene moieties, alkylene moieties, alkenylene moieties, or mixtures thereof. Arylene and alkarylene moieties which can be partially substituted for 1,4-phenylene include 1,3-phenylene, 1,2-phenylene, 1,8-naphtylene, 1,4-naphtylene, 2,2-biphenylene, 4,4-biphenylene and mixtures thereof. Alkylene and alkenylene moieties which can be partially substituted include ethylene, 1,2-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexamethylene, 1,7-heptamethylene, 1,8-octamethylene, 1,4-cyclohexylene, and mixtures thereof.
For the R¹ moieties, the degree of partial substitution with moieties other than 1,4-phenylene should be such that the soil release properties of the compound are not adversely affected to any great extent. Generally, the degree of partial substitution which can be tolerated will depend upon the backbone length of the compound, i.e., longer backbones can have greater partial substitution for 1,4-phenylene moieties. Usually, compounds where the R¹ comprise from about 50 to 100% 1,4-phenylene moieties (from 0 to 50% moieties other than 1,4-phenylene) have adequate soil release activity. For example, polyesters made according to the present invention with a 40:60 mole ratio of isophtalic (1,3-phenylene) to terephthalic (1,4-phenylene) acid have adequate soil release activity. However, because most polyesters used in fibre making comprise ethylene terephthalate units, it is usually desirable to minimize the degree of partial substitution with moieties other than 1,4-phenylene for best soil release activity. Preferably, the R¹ moieties consist entirely of (i.e., comprise 100%) 1,4-phenylene moieties, i.e. each R¹ moiety is 1,4-phenylene. (Irrespective of the mechanism of action, it is surprising that the soil release polymers do show excellent benefits on fabrics other than polyester fabrics and the compositions herein are designed to clean all manner of fabrics and textiles.)
For the R² moieties, suitable ethylene or substituted ethylene moieties include ethylene, 1,2-propylene, 1,2-butylene, 1,2-hexylene, 3-methoxy-1,2-propylene and mixtures thereof.
Preferably, the R² moieties are essentially ethylene moieties, 1,2-propylene moieties or mixture thereof. Inclusion of a greater percentage of ethylene moieties tends to improve the soil release activity of the compounds. Surprisingly, inclusion of a greater percentage of 1,2-propylene moieties tends to improve the water solubility of the compounds.
For this invention, the use of 1,2-propylene moieties or a similar branched equivalent is desirable for incorporation of any substantial part of the soil release component in the liquid fabric softener compositions. Preferably, from 75% to 100%, more preferably from 90% to 100% of the R² moieties are 1,2-propylene moieties.
The value for each n is at least 6, but is preferably at least 10. The value for each n usually ranges from 12 to 113. Typically, the value for each n is in the range of from 12 to 43.
A second type of preferred soil release polymers are polymers which comprises a copolymer having:
(i) monomer units of polyethylene and/or capped poly(ethylene glycol) having the formula I - O - (CH₂ - CH₂ - O)_n - and/or the formula Ia: X - O - (CH₂ - CH₂ - O)_n - wherein X is a hydrogen atom or a capping group, preferably a C_1-4 alkyl group; and n is an integer;
(ii) monomer units of an aromatic dicarboxylic acid, having the formula II: - CO - Ar - CO - O wherein Ar is a bifunctional aromatic group; and
(iii) monomer units of a polyol having at least 3 hydroxyl groups, having the formula III: - CH₂ - A - CH₂ - O - wherein A is a bifunctional group containing at least 1 carbon atom and at least 1 hydroxyl group.

Other Ingredients

The detergent composition of the invention may also contain a fluorescer (optical brightener), for example, Tinopal (Trade Mark) DMS or Tinopal CBS available from Ciba-Geigy AG, Basel, Switzerland. Tinopal DMS is disodium 4,4'bis-(2-morpholino-4-anilino-s-triazin-6-ylamino) stilbene disulphonate; and Tinopal DBS is disodium 2,2'bis-(phenyl-styryl) disulphonate.
An antifoam material is advantageously included in the detergent composition of the invention, especially if the powder is primarily intended for use in front-loading drum-type automatic washing machines. Suitable antifoam materials are usually in granular form, such as those described in EP 266 863A (Unilever). Such antifoam granules typically comprise a mixture of silicone oil, petroleum jelly, hydrophobic silica and alkyl phosphate as antifoam active material, sorbed onto a porous absorbent water-soluble carbonate-based inorganic carrier material. Antifoam granules may be present in any amount up to 5% by weight of the composition.
Further ingredients which can optionally be employed in the detergent composition of the invention include polymers containing carboxylic or sulphonic acid groups in acid form or wholly or partially neutralised to sodium or potassium salts, the sodium salts being preferred.
Preferred polymers are homopolymers and copolymers of acrylic acid and/or maleic acid or maleic anhydride. Of especial interest are polyacrylates, polyalphahydroxy acrylates, acrylic/maleic acid copolymers, and acrylic phosphinates. Other polymers which are especially preferred for use in liquid detergent compositions are deflocculating polymers such as for example disclosed in EP 346995.
The molecular weights of homopolymers and copolymers are generally 1000 to 150,000, preferably 1500 to 100,000. The amount of any polymer may lie in the range from 0.5 to 5% by weight of the composition. Other suitable polymeric materials are cellulose ethers such as carboxy methyl cellulose, methyl cellulose, hydroxy alkyl celluloses, and mixed ethers, such as methyl hydroxy ethyl cellulose, methyl hydroxy propyl cellulose, and methyl carboxy methyl cellulose. Mixtures of different cellulose ethers, particularly mixtures of carboxy methyl cellulose and methyl cellulose, are suitable. Polyethylene glycol of molecular weight from 400 to 50,000, preferably from 1000 to 10,000, and copolymers of polyethylene oxide with polypropylene oxide are suitable as also are copolymers of polyacrylate with polyethylene glycol. Polyvinyl pyrrolidone of molecular weight of 10,000 to 60,000, preferably of 30,000 to 50,000 and copolymers of polyvinyl pyrrolidone with other poly pyrrolidones are suitable. Polyacrylic phosphinates and related copolymers of molecular weight 1000 to 100,000, in particular 3,000 to 30,000 are also suitable.
It may also be desirable to include in the detergent composition of the invention an amount of an alkali metal silicate, particularly sodium ortho-, meta- or preferably neutral or alkaline silicate. The presence of such alkali metal silicates at levels, for example, of 0.1 to 10 wt%, may be advantageous in providing protection against the corrosion of metal parts in washing machines, besides providing some measure of building and giving processing benefits.
Further examples of other ingredients which may be present in the composition include fabric softening agents such as fatty amines, fabric softening clay materials, lather boosters such as alkanolamides, particularly the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids; heavy metal sequestrants such as EDTA; perfumes including deodorant perfumes; germicides; pigments, colorants or coloured speckles; and inorganic salts such as sodium and magnesium sulphate. Sodium sulphate, calcium carbonate may if desired be present as a filler material in amounts up to 40% by weight of the composition; however as little as 10% or less by weight of the composition of sodium sulphate, or even none at all, may be present.
In addition to the principal detergent surfactant, which is nonionic and/or amphoteric, the formulation can also contain anionic surfactant, which, at a level of up to 100 mole%, preferably 50 mole%, of the cationic softener present, may promote the softening performance of the formulation.

Product Form

The detergent compositions according to the invention may be in any suitable form including powders, bars, liquids and pastes. For example suitable liquid compositions may be nonaqueous or aqueous. The compositions may be prepared by a number of different methods according to their physical form. In the case of granular products they may be prepared by dry-mixing, coagglomeration, spray-drying from an aqueous slurry or any combination of these methods. One preferred physical form is a granule incorporating a detergency builder salt. This may be prepared by conventional granulation techniques or spray-drying.
It is preferred if compositions are in liquid form, especially preferred are transparent or translucent liquid detergents.
The invention will now be illustrated by the following nonlimiting examples. In the examples all percentages are expressed by weight.
Comparative Examples are designated by letters, while Examples of the invention are designated by numbers.

Preparation of Examples

All the formulations were prepared by heating the ingredients together in demineralised water at 70°C until a homogenous dispersion or solution was obtained.

Testing Methods

Detergency

The formulations detailed below were tested in model mixed load tergotometer experiments at a liquor:cloth ratio of 25:1. The fabric load used in each tergotometer pot comprised 3 pieces each of cotton terry towelling, cotton sheeting, 50/50 polycotton, and polyester, totalling 40g in weight. Each tergotometer run was performed three times. Wash treatments were done at 40°C for 15 minutes and were followed by a 5 minute rinse at ambient temperature. Fabrics were line-dried, following a short spin. Three wash-rinse-dry cycles were performed for each treatment prior to softness evaluation of the terry towelling and staining of each of the other fabrics with 0.05ml olive oil (highly refined, ex Sigma Diagnostics) containing a small amount of solvent violet dye. The stains were allowed to wick out for 4 days, prior to measurement of reflectance spectra and re-washing, together with the terry towelling, using the detergent system used for the pre-treatments.
After drying, reflectance spectra were again measured and percentage detergencies were calculated based on the reflectance values at the reflectance minimum (580 nm) via the Kubelka-Munk (K/S) function. Detergencies quoted are the mean values for the 9 fabric squares in each set. Percentage detergency was calculated using the equation: % Det.=100 x (K/SB - K/SA)/(K/SB - K/SC) where K/S=(1-R)2/2R where R is the reflectance at 580 nm' and the B, A, and C subscripts refer to values obtained from before wash (stained) fabric, after wash (dried) fabric, and clean (untreated) fabric, respectively.
Softening of the fabrics was assessed by an expert panel of 4 people using a round robin paired comparison test protocol. Each panel member assessed four sets of test cloths. Each set of test cloths contained one cloth of each test system under a evaluation. Panel members were asked to assess softness on a 8 point scale. Softness scores were calculated using an "Analysis of Variance" technique. Lower values are indicative of better softening.

Examples

The Examples were prepared according to the standard procedure stated.
The Examples of the invention all conformed to the testing procedures stated in the specification.
Products were dosed at 22g in the wash or, for the rinse product comparative examples, 5g in the rinse - ie. approximately the same amount of HT TMAPC was added from both wash or rinse application.
Dobanol 91-5 is C9-C11 alcohol ethoxylate (5 EO), ex Shell. Soil release polymer is a copolymer of poly(ethylene glycol methyl ether), terephthalic acid, and glycerol as described in EP 752468.
DMDAPS is 3-(Dimethyldodecylammonio) propanesulphonate, ex Fluka.
Genapol C200 is coco-alcohol ethoxylate (20 EO), ex Hoechst. HTTMAPC is 1,2 bis [dihardened tallowoyloxy] 1-3 trimethylammonium propane chloride.
The softness evaluation is shown below.
The detergency of the products is shown below.
It can thus be seen that the Examples of the invention soften fabrics effectively without any detrimental effect to the cleaning properties of the formulation.

Examples 5 to 7 and C to E

The following Examples show the advantage of using a quaternary ammonium compound having at least one ester link. The comparisons were made in the presence of two different "detergency boosters": (i) a selection of builders from Colgate's Example 3 and (ii) a soil release polymer (Permalose TM, ex ICI).
The formulations containing builder were prepared by shearing the ingredients together in a Moulinex blender until an homogeneous slurry was obtained. The formulations containing SRP were prepared by equilibrating the ingredients together at 80°C, with occasional agitation, until an homogeneous solution/dispersion was obtained.
The formulations were prepared by equilibrating the ingredients together at 80°C, with occasional agitation, until an homogeneous solution/dispersion was obtained.

Evaluation

The above Examples were each used to treat 40g portions of de-sized, terry towelling in tergotometers containing 1L water at 40°C. The dosage used was adjusted to give 0.1g/l quat. in each tergo and the agitation speed was set at 65 rpm.
After drying and equilibration at constant humidity, the softness of the terry towelling was assessed by a trained panel, who ranked the towels on a line scale where 8 represents harsh, unsoftened fabric and 2 represents very soft, conditioned fabric, as typical after use a large dose of a conventional rinse conditioner formulation.
Whilst none of the systems approach this latter level of performance on single usage, it is clear that the Examples of the patent are clearly better than the comparative Examples.
In addition Example 7 was a clear liquid, whilst comparative Example E was turpid and went cloudy on standing.

Claims

A fabric softening detergent composition comprising

i) a detergent surfactant comprising an amphoteric surfactant and/or a nonionic surfactant;

ii) a substantially water insoluble fabric softening compound having a solubility not exceeding 1 x 10^-3 wt% in demineralised water at 20°C and comprising a compound having two C_12-22 alkyl or alkenyl groups connected to a quaternary ammonium head group via at least one ester link or a quaternary ammonium compound comprising of a single chain with an average chain length equal to or greater than C₂₀ and;

(iii) a detergency booster

wherein when constituents (i) and (ii) are diluted in water to a concentration of 5 wt% of (i) and (ii), at least 70 wt% of the fabric softening (ii) compound is in solution, and further wherein the weight ratio of detergent surfactant (i) to fabric softening compound (ii) is at least 1:1.
A detergent composition according to claim 1, in which the ratio of detergent surfactant (i) to fabric softening compound (ii) is within the range from 5:1 to 30:1.
A detergent composition according to any preceding claim, which further comprises a non-surfactant solubiliser for the fabric softening compound (ii).
A detergent composition according to any preceding claim in which the detergent surfactant is an amphoteric surfactant.
A detergent composition according to anyone of claims 1 to 3 in which the detergent surfactant is a mixture of nonionic surfactant and amphoteric surfactant.
A detergent composition according to any preceding claim in which the fabric softening compound (ii) comprises a compound having two C_12-22 alkyl or alkenyl groups connected to a quaternary ammonium head group via at least one ester link.
A detergent composition according to claim 6 in which the fabric softening compound is selected from 1,2bis[hardened tallowoyloxy]-3- trimethylammonium propane chloride and di(tallowoyloxyethyl) dimethyl ammonium chloride.
A detergent composition according to any preceding claim in which the level of detergent surfactant (i) is at least 10 wt% of the total composition.
A detergent composition according to any previous claim in which the detergency booster (iii) is selected from builders, enzymes, soil release agents antiredeposition polymers, sequestants, chelates or bleach systems.
A detergent composition according to claim 9 in which the detergency booster is a soil release polymer.
A detergent composition according to any preceding claim which is in the form of self-size-limiting molecular aggregates.
A detergent composition according to any preceding claim which is in liquid form.
A detergent composition according to claim 12 which is transparent or translucent.
A detergent composition according to any one of claims 1 to 12 which is in granular or powder form.
Use of self-size-limiting molecular aggregates such as micelles or micellar solutions with solid or liquid interiors or mixtures thereof, as a fabric softening system in the fabric softening detergent composition of any previous claim.