GB2207144A - Detergent compositions comprising a softening clay and an amphoteric material - Google Patents

Abstract

A granular, built detergent composition comprises at least one bentonite clay combined with at least one amphoteric material. A heavy duty, laundering and textile softening particulate detergent composition is also provided comprising:- 1-15% by weight of a nonionic surfactant 0-15% by weight of an anionic surfactant 1-20% by weight of an amphoteric surfactant 5-25% by weight of a fabric softening clay 10-75% by weight of a builder for the surfactants.

Description

Detergent Compositions This invention relates to granular, built detergent compositions which afford simultaneous cleaning and softening of textile fabrics during the course of the laundering process.

Compositions which offer simultaneous cleaning and softening of fabrics are generally based on a compromise situation, since cleaning involves the removal of soil from the fabric while softening involves the deposition of material onto the fabric to afford the desired effect.

Softening materials are usually cationic in nature and they are reactive to the anionic materials used in conventional laundry detergents. If both types of material are formulated in the same product then the effectiveness of both functions may be appreciably reduced. Numerous attempts have been made to overcome this problem.

Initial work, carried out in the USA, was based on protecting the ractants from each other. US patents 3886075, 2954632, 3644203 and 4076072 describe this work.

An alternative approach has sought to minimise the mutual reactivity of the anionic and cationic materials by the addition of compatibilising compounds as described, for example, in US patents 3886075 and 2954632. Further developments involved the rep ace-er- cf anionics by nonionics in order to prevent the interaction. Compositions of this type are described by BP 1079388 and US 3607763.

In~1978, BP 1514276, assigned to Unilever, described the use of certain long chain tertiary amines which behave as nonionics in alkaline solutions and cationics in acid or neutral solutions. The pH area in which the ionic nature changes is termed the isoelectric point and this was chosen so that the tertiary amines functioned as nonionics in the wash cycle and cationics in the rinse cycle.

EP applications 11340 (28.5.80) and 8023367 (4.2.81) describe cleaning and softening compositions comprising a combination of a long chain tertiary amine and a smectite - type clay in an anionic surfactant based detergent. EP 23367 (Feb. '81) is based on somewhat different tertiary amines.

The use of smectite - type clays as softening agents in detergent compositions is described in BP 14go898.

A high level of incorporation is required for effective softening. USP 4292035 discloses the formation of complexes of clay and organic textile softening agents for inclusion into detergent compositions for fabric softening.

EP 076572 by Procter and Gamble (April '83) describes the application of a mixture of tertiary amine and quarternary or imidazoline type materials Smetic clay may be used to prevent caking. The quarternary of EP 076572 has also been replaced by long chain fatty acids (Procter and Gamble, Marc. '85).

Three UK applications by Colgate are concerned with the utilisation of bentonite clay materials. These are : GB 2120293A (Nov. '83), GB 2120695A (Dec. '83) and GB 2131843A (June '84).

The compromise situation implied by opposing cleaning and softening mechanisms is such that products tend to fall short of the overall desired effect. Some compositions clean well but fail to provide adequate softening, whereas with others the opposite situation applies.

The invention seeks to provide a compromise solution at high levels of performance.

According to the invention at least one bentonite clay is combined with at least one amphoteric material and incorporated into granular, built detergent compositions.

We have discovered that such a combination can provide superior cleaning performance together with textile softening/conditioning performance apprcachirg hat of rinse-added fabric conditioners.

According to a preferred embodiment of the invention there is provided a heavy duty laundering and textile softening particulate detergent composition which comprises the following : 1 - 155 by weight of a nonionic surfactant O - 15 by weight of an anionic surfactant 1 - 20% by weight of an amphoteric surfactant 5 - 259 by weight of a fabric softening clay 10 - 75% by weight of a builder for the surfactants Nonionic Surfactants A variety of nonionic surfactants, in normal commercial distribution, may be utilised in the invention. Preferred materials are ethylene oxide or propylene oxide/ethylene oxide adducts of alkylphenols (e.g. C6 - 12 phenols) or long chain alcohols or alkylamines (e.g.C1O - 18 alcohols or C 12-18 alkylamines).

Examples of preferred nonionic surfactant materials may include:a nonylphenol-ethylene oxide adduct containing 6 - 12 moles ethylene oxide.

a C10-l8 alcohol - ethylene oxide adduct containing 5 - 11 moles ethylene oxide.

a C12-18 a lkylamine - ethylene oxide adduct containing 7 - 12 moles ethylene oxide.

Equivalent ethylene oxide/propylene oxide block copolymer adducts are also suitable.

The nonionic surfactants are chosen such that they offer good detergency in respect of oily stains on soiled fabrics. They are also chosen so that they are of relatively low melting point, which is however sufficientvabove room temperature so that they may be sprayed as a liquid which solidifies.

Anionic Surfactants Again, a variety of anionic surfactants, in normal commercial distribution, may be utilised in the invention. Preferred materials, usually as their Sodium Salts, include higher alkyl benzene sulphonates, higher alkyl sulphates and higher fatty alcohol polyethoxylate sulphates.

Examples of preferred anionic surfactant materials may include:an alkyl benzene sulphonate containing about 9 - 15 carbon atoms in a linear or branched alkyl chain (e.g., a C 11-13chain).

an alkyl sulphate containing about 10 - 22 carbon atoms in the alkyl chain (e.g., a 2-18 chain).

an alkyl polyethoxylate sulphate containing about 10 - 18 carbon atoms in the alkyl chain (e.g., a C10-l6 chain) and about 1-20 ethoxy groups per molecule (e.g., 1 - 6 ethoxy groups per molecule).

Higher olefin sulphates and paraffin sulphonates, e.g., Sodium Salts in which the olefin or paraffin groups contain about 10 - 18 carbon atoms, provide further examples of suitable anionic surfactants.

Soaps are also useful anionic surfactants. Suitable soaps may contain about 8 - 24 carbon atoms (e.g, C1218).

In addition to the preferred anionic surfactants, a variety of others may be employed. These are well known in the art and are fully described in the literature.

Mixtures of anionic surfactants may be employed to advantage.

Anionic surfactants are chosen such that they offer good-detergencyin respect of particulate soil on soiled fabrics. They are also chosen as offering optimum combined cleaning/softening performance.

Amphoteric Surfactants A variety of amphoteric materials, in normal commercial distribution, may be utilised in the invention. Preferred materials have the general formula R - (CO)z - (OCH2 CH2 CH2)n

where R is a C 8-20 hydrocarbyl group, optionally substituted; R1 is H or C1-6 alkyl; B is H, alkyl or substituted alkyl, or a group Q as defined below; Q is an anionic moiety; x is 2 to 6; y is 0 to 5; z is 0 or 1; n is 0 or 1 (z being 0 when n is 1) In these compounds, R may be, for example, a straight or branched alkyl or alkenyl group; a cycloalkyl - alkyl (e.g., cyclohexyl-alkyl) group; an aralkyl or aralkenyl group in which the alkyl or alkenyl portion contains at least 6 carbon atoms; or the hydrocarbyl portion of a resinic acid containing at least two fused rings, e.g., as in the tricyclic pine resin acids such as abietic acid.

R is preferably a C 10-16 alkyl group, (e.g., C12); an example of a branched chain group is C16H33CH (CH3) The aliphatic portion of R may for example be the hydrocarbyl portion of lauric or coconut fatty acid, both of which contain a high proportion of C12 constituents.

An example of an unsaturated R group is oleyl.

R may for example be substituted by hydroxy, as in hydroxystearyl, or by - COGH (e.g., at the 2 position).

In most surfactants having the general formula detailed above n is 0.

Rl is usually a hydrogen atom but may be an alkyl group such as methyl.

When B is an alkyl group, it may have 1 - 6, preferably 2 - 4 carbon atoms and is preferably a straight chain group. Examples of such groups are methyl and ethyl. The alkyl group may be substituted for example by hydroxy, as 2 hydroxyethyl, or by amino.

The group Q may for example be of the formula R2COOM, where R is a is C16 alkylene group (such as methylene or ethylene) and M is hydrogen or alkali metal, alkaline earth metal, ammonium or substituted ammonium ion (e.g., mono, di, tri - hydroxyethylammonium).

M is preferably sodium and R2 is preferably methylene.

For the purposes of this invention and because of the change of ionic properties with pH shown by amphoteric surfactants, the free COOH group is considered equivalent to -COONa or -COOK and ammonium or amine or other carboxylic acid salts.

Examples of preferred amphoteric surfactant materials include: Type A - a surfactant of general formula as described above.

Where R is a C8-20 hydrocarbyl group derived from coco or tallow fatty acids.

R1 is H B is H or Q as defined below Q is an anionic moiety, preferrably CH2COON a or -CH2CH2 COONa n is 2 to 4 y is O to 4 z is o n is o and Type B - a surfactant of general formula as described above where R is a C8-20 hydrocarbyl group derived from coco, oleic cr tall oil fatty acids.

R1 is H B is H, hydroxyethyl or a group Q as defined below Q is an anionic moiety, preferably CH2COONa or - CH2CH2 COONa x is 2 y is 1 z is 1 n is O Examples of Type A amphoteric materials in normal commercial distribution include Deriphat 151, Deriphat 154 and the full sodium salts of Deriphat 151C, Deriphat 161C, Amphoram CP1, Diamphoram CPi, Triamphoram CP1, Polyamphoram CPI and Ampholak 7TX-C (Deriphats available from Henkel, Amphorams from Ceca and Ampholak 7TX-C from Amphoterics International Limited).

Examples of Type B amphoteric materials in normal commercial distribution include products classed as cocoamphoglycinate, cocoamphopropionate, cocoamphocarboxyglycinate and cocoamphocarboxypropionate such as Miranol CM, C2M, C2MSF and Ampholak X00-30P from Amphoterics International Limited.

Softening Clay The softening clay employed in the invention is of the type classified as bentonite. Bentonites are colloidal clays (aluminium silicates) which contain montmorillonite.

Montmorillonite is typical of a range of expandable, layered structure clays classified geologically as smectites. These have complex octahedral metal-oxygen arrangements in the centre of a layer and silicon-oxygen links in the outer part. Their expandable nature is related to the ability of the layered structure to be swollen or expanded in contact with water. Such ability is associated with the dispersing and lubricating properties of the clay.

The expandable properties of the clay are also related to the charge of the clay and to its cation exchange property. These factors are in part determined by the lattice structure. Clays suitable for use in the invention contain absorbed cations such as those of hydrogen, lithium, sodium, potassium, calcium and magnesium. It is customary to distinguish between clays on the basis of one cation predominantly or exclusively absorbed, e.g., a sodium clay contains largely Na+.

Absorbed cations can become involved in exchange reactions with cations present in aqueous solutions and cation exchange capacity is usually measured in terms of millie::uivaients per lOOg of clay.

The cation exchange capacity of clays varies widely from low values between 2 and 30 meq/lOOg for materials such as kaolinite and illite to 150 meq/100g or more for some smectites. Those materials which exhibit low values are usually of a non-expanding nature and they are not suitable for use in the compositions of this invention. Clays exhibiting ion exchange capacities of at least 50 meq/100g clay and preferably at least 60 meq/100g clay are suitable for fabric softening purposes.

Some bentonite materials with relatively low swelling capacity may be activated to increase that capacity. Thus sodium carbonate solution may be used to insert monovalent sodium ions into the clay structure to replace divalent alkaline earth materials. Such procedure also improves the exchange capacity of the clay for water hardness ions such as those of calcium and magnesium. Preferred bentonites have swelling capacities of at least 1 or 2 ml/g and more preferably 5 - 10 ml/g. The normal range will be from 5 to 30 ml/g and frequently will be in the range from 5 - 20 ml/g.

Activated and natural bentonite materials are derived from natural deposits in many countries including Italy, Greece, Spain, France, USSR, Canada and the USA (particularly Mississippi, Texas and Wyoming). Commercially available materials are supplied by many companies and mixtures of such materials are also supplied The softening clays are chosen such that they have high cation exchange capacity, good swelling properties, good colour and offer good softening properties particularly in synergistic combination with the appropriate amphoteric materials of the invention. Such clays are known also to assist in antiredeposition of soil and in absorption of fugitive dye in solution, thereby inhibiting or reducing dye transfer.

Preferred swelling bentonites will have a pH in water (at 6% concentration) in the range of 8 to 9.4, a maximum free moisture content of about 8%, a specific gravity of about 2.6 and a viscosity at 10% concentration in water within the range 5 to 30 centipoises.

Builder for the Surfactants The builder for the surfactants assists in the laundering process and may be inorganic or organic in character. Mixtures may also be used. Non-limiting examples of water-soluble, inorganic alkaline detergent builder salts include alkali metal carbonates, bicarbonates, phosphates, polyphosphates, silicates and borates.

Specific examples of such salts include sodium and potassium carbonates and bicarbonates, pyrophosphates, tripolyphosphates, pentapolyphosphates hexametaphosphates, tetraborates and disilicates. Preferred watersoluble inorganic builder salts are sodium tripolyphosphate and sodium silicate and usually both are present. Sodium tripolyphosphate is of particular importance in compositions of the invention both because it has excellent detergent builder properties and because it helps to disperse clay material quickly and homogeneously through the laundering solution without interfering with clay deposition on the fabric surface.

Non-limiting examples of watersoluble, organic alkaline detergent builder salts include trisodium nitriloacetate (NTA), ethylene diamine tetracetic acid (EDTA, preferably as the sodium salt) and other amino polyacetates, water-soluble polyphosphonates and watersoluble polycarboxylates, citrates and gluconates.

Water insoluble builders can be used in the invention. These are exemplified by the zeolites which soften the wash water through removal of calcium ions by an ion exchange mechanism.

Builders are chosen generally such that they are effective in removing calcium and magnesium ions which cause water hardness, by sequestration, precipitation or ion exchange. Detergent builder materials are normally included in compositions in amounts from 10 to 75% by weight of the composition, preferably from 20 to 70% and most usually from 30 to 60% by weight.

Other Components of the Compositions All of those materials which are normally included in built laundry detergents may be present. These include: bleaching agents, e.g., sodium perborate and activating agents therefor, e.g., tetra acetyl ethylenediamine; soil suspending agents, e.g., sodium carboxymethylcellulose; enzymes of proteolytic, amylolytic or lypolytic types; suds boosters; e.g., mono or di-ethanolamides of fatty acids; suds suppressors, e.g., of silica/silicone type; optical brightening agents; non-substantive colours; perfumes; sodium sulphate, which functions as a filler and as a processing aid which provides a crispness and stability to the granular particles of the detergent composition.

Preparation of the Compositions The compositions may be prepared by mixing the components. Preferably however, they are granular and are produced by the usual wellestablished spray-drying or agglomeration techniques. The clay component may be added at the beginning of the granulation process and thus incorporated into the granule or it may be dry-mixed after the granulating process if so desired.

Prepared compositions are added to water to provide laundering solutions containing from 0.02% to 2% by weight of the compositions.

Soiled fabrics are added to the laundering liquor and cleansed in the usual way.

Examples The invention is illustrated by the following non-limiting examples.

Example 1 Granular, built, textile softening detergent compositions were prepared having the formulae, in parts by weight, as follows: 1 2 3 4 Nonionic Surfactant 1.8 1.8 1.8 1.8 Anionic Surfactant 5.0 5.0 5.0 5.0 Ampholak 7TX-C - - 5.0 5.0 Bentonite Clay - 10.0 - 6.0 Sodium tripolyphosphate 25.0 25.0 25.0 25.0 Sodium Carbonate 20.0 20.0 20.0 20.0 Sodium Silicate (Ratio Si 02: Na2 0 = 2) 3.5 3.5 3.5 3.5 Sodium Perborate 12.5 12.5 12.5 12.5 Enzyme 0.45 0.45 0.45 0.45 Optical Brighteners 0.15 0.15 0.15 0.15 Suds Suppressor 0.2 0.2 0.2 0.2 Sodium Carboxymethylcellulose 1.5 1.5 1.5 1.5 Sodium Sulphate Balance Balance Balance Balance Formula 1 was prepared as a reference sample, containing no amphoteric surfactant and no clay.

In carefully controlled wash tests, using similarly soiled textile test pieces and similar quantities of the various compositions at similar concentrations, all four compositions showed good cleaning performance in both hard water (300 ppm Ca C03) and soft water (15 ppm Ca CO3).

The compositions of Formulae 2, 3 and 4 had as good cleaning performance as that of Formula 1.

Cotton test pieces washed amongst a naturally soiled wash load with the compositions of Formulae 2, 3 and 4 were softer in feel than similar pieces washed with the composition of Formula 1.

Good softening performance was observed from compositions of Formulae 2, 3 and 4 when terry towelling was washed under carefully controlled conditions, in both hard and soft water.

Panel testing techniques indicated that the softening performance of the composition of Formula 4 was superior to that of the compositions of Formulae 2 to 3, Formula 4 was the only composition containing both amphoteric surfactant and bentonite clay and its performance was superior even with the clay content reduced to 6% W/w.

Example 2 Granular, built, textile-softening detergent compositions were prepared having the formulae, in parts by weight, as follows: 5 6 Nonionic Surfactant 1.8 1.8 Anionic Surfactant - 0.5 Ampholak 7TX-C 5.0 5.0 Bentonite Clay 10.0 10.0 Sodium Tripolyphosphate 25.0 25.0 Sodium Carbonate 20.0 20.0 Sodium Silicate (Ratio Si 02: Na20 = 2) 3.5 3.5 Sodium Perborate 12.5 12.5 Enzyme 0.45 0.45 Optical Brightener 0.15 0.15 Suds Suppressor 0.2 0.2 Sodium Carboxymethylcellulose 1.5 1.5 Perfume 0.15 0.15 Sodium Sulphate Balance Balance The compositions of Formulae 5 and 6 both exhibited good textile softening properties after one wash cycle and particularly so after five wash cycles.

The cleaning performance of compositions of Formulae 6 was enhanced by comparison with that of compositions of Formula 5, in both hard and soft water. This was a consequence of the inclusion of the anionic surfactant. Similar cleaning performance was obtained when the anionic surfactant was a linear alkyl benzene sulphate and when it was a paraffin sulphonate.

Example 3 A granular, built, textile softening detergent composition was prepared, having the formula, in parts by weight as follows: 7 Nonionic Surfactant 2.0 Anionic Surfactant 5.0 Ampholak 7TX-C 3.2 Ampholak X00-30P 0.8 Bentonite Clay 6.0 Sodium Tripolyphosphate 25.0 Sodium Carbonate 20.0 Sodium Silicate (Ratio: Si 02 : Na2 O = 2) 3.5 Sodium Perborate 12.5 Enzyme 0.45 Optical Brightener 0.15 Suds Suppressor 0.35 Sodium Carboxymethylcellulose 1.5 Perfume 0:2 Sodium Sulphate- Balance A commercially available granular, built, textile softening detergent composition, coded 'X was compared to compositions of Formula 7 in a carefully controlled series of texts. The overall winner of each test category was awarded 5 points and the other compositions was awarded marks relative to performance.

The overall comparison was made as follows :a. Cleaning Formula 7 Detergency 5 4 Oxidisable stain removal 5 5 Protein stain removal 5 3 Optical whitening 5 4 Antiredeposition of soil 5 5 b. Softening Lubricity ('handle') 4 5 Loftiness (Height of equal pile of nappies similarly folded) 5 4 Rewetting property 5 5 Antistatic property 4 43 40 Terry towelling nappies washing in compositions of both Formula 7 and 'X' exhibited good residual freshness.

Claims (16)

Claims

1. A granular, built detergent compositions comprising at least one bentonite clay combined with at least one amphotenic material.

2. A heavy duty, laundering and textile softening particulate detergent compositions which comprises 1 - 15% by weight of a nonionic surfactant O - 15% by weight of an anionic surfactant 1 - 20% by weight of an amphoteric surfactant 5 - 25% by weight of a fabric softening clay 10 - 75% by weight of a builder for the surfactants

3. A dtergent composition according to Claim 2, which when dissolved in water at a concentration of 0.1% by weight affords a solution pH between 7.5 and 11.5.

4. A detergent composition according to Claim 2, in which the amphoteric surfactant is of the general formula : R - (CO)z - (OCH2 CH2 CH2)n

where R is a C 20 hydrocarbyl group, optionally -2O substituted; R is H cr C16 aklyl; B is H, alkyl or substituted alkyl, or a group Q as defined below Q is an anionic moiety; X is 2 to 6; y is O to 5; z is O or 1; n is o or 1 (z being 0 when nazis 1).

5. A detergent composition according to Claim 4, in which the amphoteric surfactant is of the type described as tallow amphopolycarboxyglycinate and in which z is 0.

6. A detergent composition according to Claim 4 in which there are two ampoteric surfactants, for one of which z is 0 and for the other of which z is 1.

7. A detergent composition according to Claim 6 in which the weight ratio of the two amphoteric surfactants (z = 0) : (z = 1) is from 3 : 1 to 2 : 1.

8. A detergent composition according to Claim 2 which contains a nonionic surfactant.

9. A detergent composition according to Claim 8 in which the ratio of amphoteric surfactant to nonionic surfactant is from 3 : 1 to 1.5 : 1.

10. A detergent composition according to Claim 2 which contains an anionic surfactant.

11. A detergent composition acording to Claim 10 in which the ration of amphoteric surfactant to anionic surfactant is from 8 : 1 to 1 : 1.

12. A detergent composition according to Claim 1 which contains one or more builders, chelating or sequestering agents, bleaching agents and activators therefor, soil suspending agents, enzymes, suds boosters, suds suppressors, optical brightening agents, non-substantive colours or perfumes, as additives.

13. A detergent composition according to Claim 11 in which the builder content is 10 - 75% by weight of the total content, preferably 20 - 70% by weight, more preferably 30 - 60% by weight.

14. A detergent composition according to any of the preceding claims which contains up to 25% of a colloidal, fabric-softening, bentonite clay having an ion exchange capacity of at least 50 meq per 100 grams.

15. A detergent composition having any one of the formulae 2 to 7 described in the foregoing example.

16. A method of preparing a granular, built detergent composition according to any of the preceding claims by means of spray-drying or agglomeration.