As normally manufactured, compounds of Formula (1) have a yellowish tinge which, depending upon the method of manufacture, their formulation and conditions of storage, can impart an undesirable discolouration to the finished detergent.

Surprisingly, it has now been found that a specific formulation of compound (1) is able to overcome this disadvantage.

Accordingly, the present invention describes a liquid fluorescent whitening agent formulation comprising : a) a compound of Formula (1) in which R, represents hydrogen, 1-5 C-alkyl, 1-5 C-alkoxy or halogen, M represents hydrogen, an alkaline-or alkaline earth-metal, or ammonium ; b) a polyhydroxy compound ; c) 5 to 95% water, whereby the ratio of the compound of Formula (1) to the polyhydroxy compound is between 10 : 90 and 90 : 10 parts by weight and the total weight of these compounds in the formulation is between 5 and 95% and, optionally, d) auxiliary stabilizing agents.

Preferably, the optical whitening agent is of the formula (2), the compound of formula (2) being most preferred.

The potyhydroxy compound, component b) of the formulation is, preferably, a triol such as 1, 2, 6-hexanetriol, glycerine or an oligomer of glycerine such as a di-, tri-or polyglycerine, glycerine being most preferred.

A preferred formulation comprises a) 10 to 45 % of the compound of formula (2) ; b) 5 to 90% of glycerine ; c) 5 to 85% of water and auxiliary stabilizing agents, whereby a formulation comprising a) 20 to 40 % of the compound of formula (2) ; b) 10 to 80% of glycerine ; c) 5 to 70% of water and auxiliary stabilizing agents is particularly preferred.

When, in formula (1), R, represents 1-5 C-alkyl, these may be methyl, ethyl, n-or isopropyl, n-, sec-, or t-butyl, n-pentyl, iso-amyl or sec-amyl groups. When, in formula (1), Ri represents 1-5 C-alkoxy, these may be methoxy, ethoxy, n-or isopropoxy, n-, sec-, or t- butoxy, n-pentyloxy, iso-amyloxy or sec-amyloxy groups. When, in formula (1), R 1 represents halogen, these may be fluorine, chlorine, bromine, or iodine, preferably chlorine.

Optional auxiliaries which may be present in the formulation of the present invention include stabilizers which are effective in adjusting the flow properties and phase stability of the formulation, preservatives, anti-foam agents, alkaline agents, fabric softeners, anti- redeposition agents, auxiliary builders such as polyacrylic acid and fragrances.

Examples of such stabilizers include, e. g., kaolin, an Mg/AI silicate, especially bentonite, montmorillonite, a zeolite or a highly dispersed silicic acid.

The formulation of the present invention may be produced by mixing the components a) to c) together with any optional auxiliaries, and homogenizing the mixture so obtained, preferably at an elevated temperature, e. g. at 40-100°C. Mixing is conveniently effected by a suitable stirring device.

The resulting formulation is either a clear solution or a flowable dispersion.

The formulation of the present invention is particularly suitable for incorporation into a detergent composition. Conveniently, the required amount of the formulation of the present invention is added to the detergent ingredients prior to the homogenization, granulation and drying procedures. Homogenizing may be performed either by a slurry-making process or by incorporation into an agglomeration device, such as a high shear mixer. Drying may be performed either in a spray drying tower or on a fluidized bed. The formulation of the present invention may also be suitable for incorporation into a dry detergent composition, conveniently by adding the required amount of the formulation to a dry detergent composition and then homogenizing the mixture so obtained. The formulation of the present invention may also be used, however, for the production of liquid detergents by adding the required amount of the formulation to a liquid detergent composition and then homogenizing the mixture so obtained.

Washing agents which can be used are the known mixtures of detergent substances, such as, for example, soap in the form of chips and powders, synthetic products, soluble salts of sulphonic acid half-esters of higher fatty alcohols, arylsulphonic acids, which are substituted by higher alkyl and/or polysubstituted by alkyl, carboxylic acid esters with alcohols of medium to higher molecular weight, fatty acid acylaminoalkyl-or aminoaryl-giycerol- sulphonates, phosphoric acid esters of fatty alcohols and the like. So-called"builders"which can be used are, for example, alkali metal polyphosphates and alkali metal polymeta- phosphates, alkali metal pyrophosphates, and also alkali metal silicates, alkali metal carbonates, alkali metal borates, nitrilotriacetic acid and ethylenediamine-tetraacetic acid.

Furthermore, the washing agents can contain, for example : alkali metal salts of carboxymethylcellulose and other"soil redeposition inhibitors", alkali metal perborates, foam stabilisers, such as alkanolamides of higher fatty acids antistatic agents, superfatting skin protection agents, such as lanolin, enzymes, antimicrobial agents, perfumes and dyestuffs.

Typically, a phosphate built conventional detergent powder formulation may consist of : Anionic surfactants 7-15% Nonionic surfactants 0-5% Soap 2-4% Sodium tripolyphosphate 25-50% Silicates 5-8% Carboxymethyl cellulose 0. 5-1. 5% Phosphonates 0. 2-0. 6% Sodium sulphate 15-25% Fluorescent whitening agent 0. 05-0. 5% Water 10%.

Fragrances 0-1 % The following Examples further illustrate the present invention. Parts and percentages shown therein are by weight unless otherwise stated.

Example 1 A reaction vessel equipped with stirrer and heating bath is charged with 250g of glycerine.

The glycerine is heated to 60°C and 232g of a moist filter cake containing 54% of the compound of Formula (2) is added while stirring. The obtained slurry is cooled to room temperature and 19g of water are added to yield a formulation containing : 25% of the compound of Formula (2) 50% of glycerine and 25% of water, as a slightly viscous, yellowish liquid.

0. 6 g of this formulation was added to an aqueous suspension of a laundry detergent, containing 100g of detergent ingredients. After stirring for 10 minutes a suspension was obtained which showed homogeneous fluorescence under UV radiation. After drying, a white detergent powder was obtained which remained white under various storage conditions (22°C, 40% rel. humidity, 30°C, 70% rel humidity) Examples 2-4 By proceeding as described in Example 1, but employing appropriate quantities of moist 54% filter cake of compound (2), glycerine and water, the formulations described in the following Table 1 are obtained : Table 1 Example 2 Example 3 Example 4 Compound (2) 26. 0% 30. 0% 30. 0% Glycerine 51. 9% 15. 0% 30. 0% Water 22. 1% 55. 0% 40. 0% Colour yellowish yellow yellowish Viscosity (visual) liquid slightly viscous viscous Examples 5-8 By following the procedure described in Example 1, but performing the mixing process at room temperature (approximately 22°C) instead of at 60°C, the formulations described in the following Table 2 are obtained : Table 2 Example 5 Example 6 Example 7 Example 8 Compound (2) 23. 0% 26. 0% 31. 4% 35. 1% Glycerine 57.5% 51.9% 41. 9% 35. 51. 9% 41. Water 19.5% 22.1% 26.7% 29.8% Colour almost white yellowish yellowish yellowish Viscosity (visual) j viscous viscous slightly viscous viscous Example 9 The formulation of Example 8 is warmed at 60°C for 2 hours and subsequently stored at room temperature, whereupon a viscous yellow liquid results.

Examples 10-24 To a glycerine/water solution, previously warmed to 60°C, appropriate quantities of the dried compound of formula (2) are added in portions with stirring. After stirring for a total time of 2. 5 hours, the formulations are stored for 24 hours at room temperature and then milled with twice their weight of glass beads (diameter 2mm) for 30 minutes at 500 rpm. Colour and viscosities of the formulations are visually assessed before and after milling.

The results are summarized in the following Tables 3 to 5 : Table 3 Example 10 Example 11 example 12 Example 13 4 Example 14 Compound (2) 15. 0% 15. 0% 20. 0% i 20. 0°0 20. 0% Glycerine 28.0% 43.0% 18.0% 33.0% 48.0% Water 57.0% 42.0% 62.0% 47.0% 32.0% Colour1 yellow yellow yellow yellow yellow Viscosity fluid fluid fluid fluid fluid Colour2 white yellowish yellow almost white almost white Viscosity2 fluid fluid fluid fluid fluid before milling 2 after milling Table 4 Example 15 Example 16 Example 17 Example 18 Example 19 Compound (2) 20.0% 25.0% 25.0% 25.0% 30.0% Glycerine 63.0% 23.,0% 38.0% 53,.0% 28.0% Water 17.0% 52.0% 37.0% 22.0% 42,.0% Colour1 almost white almost white yellow yellowish yellow Viscosity1 viscous fluid fluid liquid fluid Colour2 white pale yellow almost white almost white white Viscosity2 slightly liquid fluid fluid liquid viscous before milling 2 after milling Table 5 Example 20 Example 21 Example 22 Example 23 Compound (2) 30.0% 35.0% 35.0% 35.0% Glycerine 43.0% 18.0% 33.0% 48.0% Water 27.0% 47.0% 32.0% 17.0% Colour'yellowish almost white Viscosity¹ liquid slightly viscous liquid slightly viscous Colour² almost white almost white white white Viscosity² liquid viscous liquid slightly viscous before milling 2 after milling Examples 24 and 25 21 g of the dry compound of formula (4) are added to 84g of deionised water and the suspension milled with 210g of glass beads (diameter 1 mm) in a wet-mill for 2 hours. After separating the glass beads, the appropriate quantity of glycerine is added and mixed at room temperature until a homogenous formulation is obtained.

The results are summarized in the following Table 6 : Table 6 Example 24 Example 25 Compound (4) 16. 65% 10. 0% Glycerine 16. 65% 50. 0% Water 66. 7% 40. 0% Colour white white Viscosity (visual) liquid liquid No change in either colour or viscosity was observed after aging of the formulations.