Washing with a commercially available laundry detergent removes the soil from the textile materials and usually imparts an improved appearance to them. However, washing and drying of textiles does not always remove bacteria to the desired degree. Nor does a normal wash do anything to prevent subsequent contamination by undesirable bacteria.

Existing ways to make textile fibre materials germ free include for example the use of beaches, higher temperatures or irradiation with strong sunlight during drying.

It has now been found that, surprisingly, optical brighteners from the class of the stilbene compounds which are customarily used in the laundry detergent and textile industries have antimicrobial properties when the textile material is simultaneously irradiated with a light source.

The present invention accordingly provides for the use of a laundry detergent that comprises at least one optical brightener from the class of the stilbene compounds for the antimicrobial finishing of textile fibre materials, which comprises washing the fibre materials with this laundry detergent and subsequently exposing the washed textile material to a light source.

Useful optical brighteners for the invention preferably conform to the formula wherein Ri is a radical of the formula R3 is substituted or unsubstituted alkyl or aryl ; R4 is M or substituted or unsubstituted alkyl or aryl ; R5 is hydrogen ; substituted or unsubstituted alkyl or aryl ; or-NR7Ra, wherein R7 and R8 are independently hydrogen ; substituted or unsubstituted alkyl or aryl ; or R7 and R8 combine with the joining nitrogen atom to form a heterocyclic radical, especially morpholino or piperidino radical ; R6 is hydrogen or substituted or unsubstituted alkyl or aryl, R2 is hydrogen ; substituted or unsubstituted alkyl or aryl ; a radical of the formula -OH ;-NH2 ;-N (CH2CH20H) 2 ;-N [CH2CH (OH) CH3] 2,-NH-R4,-N (R4) 2 or-OR4 ; or Ri and R2 are independently-OH,-Cl ; -NH2, -O-C1-C4alkyl, -O-aryl, -NH-C1-C4alkyl, -N (C1-C4alkyl)2, -N(C1-C4alkyl)(C1-C4hydroxyalkyl), -N(C1-C4hydroxyalkyl)2, or -NH-aryl, morpholino, S-Ci-C4alkyl (aryl), Rg and Rio are independently hydrogen, C1-C4alkyl, phenyl or a radical of the formula R11 is hydrogen, Cl or S03M ; R12 is -CN, -SO3M, -S (C1-C4alkyl) 2 or S (aryl)2; R13 is hydrogen, -SO3M, -O-C1-C4alkyl, -CN, -Cl, -COO-C1-C4alkyl, or CON(C1-C4alkyl)2; R14 is hydrogen ;-Ci-C4alkyl,-Cl or-SO3M ; R15 and Ris are independently hydrogen, C1-C4alkyl,-S03M,-Cl or-O-C1-C4alkyl ; R17 is hydrogen or Ci-C4alkyl ; R18 is hydrogen, Ci-C4alkyl,-CN,-Cl,-COO-Ci-C4alkyl,-CON (Ci-C4alkyl) 2, aryl or-O-aryl ; M is hydrogen, Na, K, Ca, Mg, ammonium, mono-, di-, tri-or tetra-C1-C4alkylammonium, mono-, di-or tri-C1-C4hydroxyalkylammonium or ammonium that is di-or trisubstituted with a mixture of Ci-C4alkyl and Ci-C4hydroxyalkyl groups ; and ni, n2 and n3 are independently 0 or 1.

(Substituted or unsubstituted) alkyl R2, R3, R4, R5, R6, R7 and R8 is C1-C12alkyl, preferably C1-C4alkyl. Alkyl may be branched or unbranched and may be substituted by halogen, for example fluorine, chlorine or bromine, C1-C4alkoxy, for example methoxy or ethoxy, phenyl or carboxyl, Ci-C4alkoxycarbonyl, for example acetyl, mono-or di-C1-C4alkylamino or-SO3M.

(Substituted or unsubstituted) aryl R2, R3, R4, R5, R6, R7 and R8 is preferably a phenyl or naphthyl group which may be substituted by C1-C4alkyl, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl, Ci-C4alkoxy, for example methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy or tert-butoxy, halogen, for example fluorine, chlorine or bromine, C2-C5alkanoylamino, for example acetylamino, propionylamino or butyrylamino, nitro, sulfo or di-C1-C4alkylated amino.

The compounds of the formula (1) are preferably used in neutralized form, i. e.

M is preferably a cation of an alkali metal, especially sodium, or an amine.

In the compounds of formula (1), Ri is preferably a radical of the formula wherein R3 is as defined above and is preferably C1-C4alkyl, especially methyl or ethyl ; or a radical of the formula wherein R5 is as defined above and is preferably C1-C4alkyl, especially methyl or ethyl, or-NR7R8, wherein R7 and R8 are each as defined above and are each preferably hydrogen, C1-C4alkyl, especially methyl or ethyl, a morpholino or piperidino radical, most particularly hydrogen, or a radical of the formula wherein R6 is as defined above and is preferably-SO3M substituted C1-C4alkyl, especially methyl-or ethyl-substituted-S03M, wherein M is as defined above and is preferably sodium ; and R2 is preferably The compounds of the formula (1) are reparable under known reaction conditions by reacting cyanuric chloride with appropriate aminostilbenesulfonic acids and with an amino compound capable of introducing an R1 group and with a compound capable of introducing an R2 group, R1 and R2 being as defined above.

Optical brighteners that are advantageously useful in the present invention are recited below in Table 1 by way of example : Table 1 : Compounds of the formula NH-CH3 CH3 N NH NH-\ N SO, Na \-N NH <NFN b Nu Na03S Table 1 : Compounds of the formula 0 (10) 0 N-' Non (10), N SO. NA N N-C N NFN b NU Nazis NAOS NU N--<, NH NH-. N SOgNa \ t C < NF b N-N/\)---NH Nu NAOS (12) NH &H3 H3C\ N==/HOCH, CH,-N N-\ SOa)-N HOCHZCH2 N N NH NH oN » N t NH Nazis Table 1 : Compounds of the formula NH-CZHS C2H5 (13) N=< NH NH- S03Na N/C2H5 H5c2 N /- NH Nazi NU (14) o nu Nan (14) N SO, Na \-N N/= (N \O-CH3 NH <N>N e NaO3S NaOgS S03Na Na03s ci ci Na03s NaS03 Table 1 : Compounds of the formula (17) Nazis NaS03 o (18) NH NH-CH3 CH3 N-< NH -4 /°)-N N4 N -N NH N nu HOgS 0 NH SO3Na (19) Nazis Table 1 : Compounds of the formula i (20) SOSK N N Kas N non Na03S (21) S03Na N /N N SONNA na 3s SO. NA (so3Na),, (22) NAOS N N Nazi SO3Na NaO3S (23) S ; Table 1 : Compounds of the formula SO3Na SO3Na (24) H C CH 0 0 CH3 CH3 H C CH3 H3C CH HIC NaO3S O ° SO3Na 26) NaO, S-0-\ CH3 (27) 'frS (C2Hs) 2N O o The stilbene compounds used in the invention have a pronounced antimicrobial action, especially against pathogenic Gram-positive and Gram-negative bacteria.

They are therefore useful for the treatment, especially decontamination and also antimicrobial finishing of textile fibre materials. Useful textile fibre materials include undyed and dyed or printed fibre materials, for example in silk, wool, polyamide or polyurethanes, and especially cellulosic fibre materials of any kind. Such fibre materials include for example natural cellulose fibres, such as cotton, linen, jute and hemp, and also pulp and regenerated cellulose. Preferred suitable textile fibre materials are composed of cotton.

The textile materials may be present in various forms. Preference is given to piece goods, such as formed-loop knits or wovens, or else yarn on packages, warp beams, etc.

To provide an antimicrobial finish, the optical brighteners which are useful according to the invention can be incorporated into liquid and solid laundry detergents.

For this they are generally diluted with further auxiliaries or water to the optimum concentration for the particular use.

The formulations thus obtained may additionally include the customary formulation auxiliaries such as dispersants, builders, protective colloids, stabilizers, preservatives, scents, pigments, enzymes and also sequestrants.

Preferred dispersants are nonionic dispersants, for example fatty alcohols, ethoxylation products of fatty alcohols or fatty acids, or anionic dispersants, such as the condensation products of aromatic sulfonic acids with formaldehyde, for example those based on oxyditolyisulfonic acid or naphthalenesulfonates, or ligninsulfonates.

Useful builders or protective colloids include for example modified polysaccharides which are derived from cellulose or heteropolysaccharides such as xanthan, carboxymethylcellulose and also aluminium silicate or magnesium silicate.

Useful stabilizing assistants include for example ethylene glycol, propylene glycol and further dispersants.

For the process of the invention, the textile fibre materials are subjected for example to a customary wash cycle in a wash liquor that includes the corresponding optical brightener.

The irradiation with UV light or in daylight preferably takes place after the textiles have been removed from the wash liquor, in the moist state, and the preferred light source is sunlight.

Illumination can in this case conveniently take place during the drying of the textiles. When the textiles are not line dried, but are dried for example in a tumble dryer, illumination may also be effected during this drying process, for example by means of a suitable artificial light source attached to or in the tumble dryer.

The examples which follow illustrate the invention.

Example 1 : Wash test a) Formulation of laundry detergent powder used (in per cent of the total weight of the formulation) : 8% of alkylbenzenesulfonate 5% of alcohol ether sulfate 2% of alcohol ethoxylate (nonionic) 30% of sodium tripolyphosphate 20% of sodium carbonate 8% of sodium silicate 18. 9% of sodium sulfate 1% of enzymes 1 of polycarboxylates 0. 1% of perfume oil 6% of water b) Preparation of laundry detergent powder which includes Tinopal CBS-X : 0. 06 part of the brightener of the formula (101) reported in Example 2 is placed in a mortar together with a small amount of deionized water and then pestled with a further 15 parts of deionized water. 20 parts of the laundry detergent powder specified above under a) are then added within a short time, and the pestling continues to form a homogeneous mass. The mass obtained is placed in a crucible and air dried at 60°C for about 12 hours.

Following two successive sieving operations (0. 8 mm mesh and then 0. 315 mm mesh) the granules obtained range in size from 0. 315 to 0. 8 mm. c) Wash with the laundry detergent obtained according to b) : A Linitest laboratory washing machine is used to wash 10 parts of bleached cotton fabric with 100 parts of tap water and 0. 4 part of the laundry detergent obtained as per b) at 25°C for 15 minutes. After the wash, the fabric is rinsed three times under running tap water and then dried in sunlight. The fabric thus washed possesses antimicrobial activity. Example 2 : Determination of antimicrobial activity of Tinopal CBS-X after irradiation with light The optical brightener of the formula is incorporated in agar plates and subsequently inoculated with bacteria and irradiated with xenon light for 10 minutes or 30 minutes.

The test is used to detect antimicrobial activity by comparison with unirradiated samples.

To this end, a 1. 5% stock solution in DMSO is prepared.

0. 5 and 0. 1 ml of this solution are added to 15 ml of liquid agar (final concentration : 500 and 100 ppm).

After solidification and drying, a bacterial mixture of Staphylococcus aureus and Escherichia coli is plated out on the agar (final concentration cfu/ml : ~105). The plates are fixed on cotton by means of double sided Scotch tape and are irradiated with a xenon lamp for 10 or 30 minutes.

Unirradiated agar plattes including 100 and 500 ppm of Tinopal CBS-X and agar plates without Tinopal are incubated as controls.

All plates were incubated at 37°C for about 48 hours. After incubation, viable bacteria are counted (see Table 1).

Examples of test germs : Bacteria : Staphylococcus aureus ATCC 9144 Escherichia coli NCTC 8196 Cultures 18 to 24 hours in casein soymeal peptone broth diluted 1 : 5000 (Staph.) and 1 : 10, 000 (E. coli) and mixed together The results are summarized in Table 1.

Table 1 Test organisms--> Staphylococcus aureus ATCC 9144/ Escherichia coli NCTC 8196 Sample 10 minutes 30 minutes Tinopal CBS-X 500 ppm (irradiated with 3. 0 x 104. 1. 5 x 102 xenon light) Tinopal CBS-X 500 ppm control substance 4.3 x 104 (t: 0') --- (not irradiated with xenon light) Tinopal CBS-X 100 ppm (irradiated with 2. 3 x 104 5. 1 x 102 xenon light) Tinopal CBS-X 100 ppm control substance 4 4 x 104 (t-0') (not irradiated with xenon light) DMSO control substance (irradiated with 5. 7 x 104 4. 5 x 104 xenon light) DMSO control substance (not irradiated 8.9 x 104(t: 0') --- with xenon light) Agar control substance (irradiated with 4. 1 x 104 3. 3 x 104 xenon light) Agar control substance (not irradiated with 2. 7 x 105 (t : 0') xenon slight) The table reports the number of colony-forming units of bacteria after 10 minutes'and 30 minutes'irradiation.

The results of Table 1 show that 100 ppm or 500 ppm Tinopal CBS-X incorporated into agar nutrient medium is effective to substantially reduce the microorganisms (mixture of Staphylococcus aureus and Escherichia coli) after 30 minutes'irradiation with a xenon lamp compared with the agar plates containing unirradiated Tinopal CBS-X and agar plates containing no Tinopal CBS-X.