Process and composition for treating fabrics

Abstract: A process and composition for treating fabrics or textiles to help restore and/or prevent changes in hue brought about by fluorescer agent absorption on fabrics or textiles. In one aspect, the composition comprises a quenching agent and a detergent active.

Description: This invention relates to the use of a fabric or textile treatment composition to help to restore and/or prevent changes in hue brought about by fluorescer agent absorption on fabrics or textiles. Fluorescer agents or optical brighteners as they are sometimes known are a common component in heavy duty detergent formulations intended for washing fabrics or textiles since the fluorescer, by absorbing invisible ultraviolet light and re-emiting blue or green visible light masks the undesirable yellow tint of textiles or fabrics and thus brightens them. Thus fabrics or textiles treated with fluorescers appear whiter and more attractive to the consumer. A disadvantage of fluorescer agents is however that undesirable absorption of fluorescer onto coloured fabrics can cause those coloured fabrics to change hue. In the context of the present invention by changes in hue is meant a change in shade or depth or colour. This is most noticeable when for example one part of a suit is fluorescent agent damaged or napkins but not the tablecloth of a dining set are fluorescent agent damaged. The effect is also particularly noticeable on pastel shades. The undesired absorption of fluorescent agents usually occurs by one or both of two routes. The first is where coloured fabrics or textiles are washed with a detergent composition comprising fluorescent agents and the second is where coloured fabrics are washed with fabrics already having fluorescent agent absorbed on their surfaces and transfer occurs. In the past there have been attempts to solve this problem of undesired fluorescent agent absorption by preventing the absorption for example by using a detergent composition without fluorescent agent or by removing the fluorescent agent from the solution. For example DE 2 916 656A (Henkel) discloses an optical brightenerfree detergent composition comprising alkyl-pyridinium salts to remove optical brighteners from solution. These proported solutions are not satisfactory because even if the detergent composition contains no fluorescent agent, articles in the wash load previously treated with fluorescent agent can give rise to transfer and because the choice of compatible detergent actives for these compositions is limited. An alternative approach to solving the problem has been to attempt to mask the fluorescent agent once it has been absorbed on the coloured fabric. Such a solution is proposed for industrial, synthetic textile pretreatment or after treatment in GB 2 174 731 A (Sandoz Ltd) where the textile is brought into contact with a UV-absorber which is then fixed on the textile. The UV-absorber is in competition for UV light with the fluorescent agent and thus in theory will reduce re-emmission by the fluorescent agent in the visible spectrum. A similar solution is proposed in EP 0 310 083A (Ciba-Geigy). US-A-3 875 071 and JP-A-61 086933 also disclose compositions containing UV-absorbers. The disadvantage of this approach is that relying on a UV-absorber alone to mask the fluorescent agent requires a high level of UV absorber to be deposited on the textile in order to compete effectively for UV-light. The present invention seeks to provide a process for treating fabrics and textiles which restores original colour and/or prevents changes in hue brought about by fluorescent agent absorption on fabrics or textiles. We have now found that the undesirable effect of fluorescent agents on textiles or fabrics can be masked not only by the UV-absorber mechanism but also by the formation of a complex which prevents the agent re-emitting in the visible spectrum. In the present invention the reduction or prevention of re-emission of light by a fluorescent agent is termed quenching and the agent which achieves quenching is termed a quenching agent. Quenching agents can achieve quenching by a process of complexation. Certain quenching agents are known from the paper industry for example as disclosed in GB 1 490 077, US 4 695 405, US 3 542 642, FR2 004 010, GB 2 066 317 and EP 217 256 for quenching fluorescent agents on recycled paper. Certain quenching agents are also known for application to textiles as part of an industrial treatment process from GB 2 178 076A. The compositions described therein are well-adapted for direct application to textile fibres for example by padding. Accordingly, the present invention provides the use of a fabric or textile treatment composition in the rinse step of a fabric laundering process, to restore original colour and/or prevent chances in hue caused by fluorescent agents, characterised in that the composition comprises: (i) from 1 to 70% by weight of a water insoluble fabric softening material; and (ii) from 0.01 to 60% by weight of a quenching agent. The quenching agents suitable for use in the process and composition of the invention are cationic species for example Cartarex 2L or Cartarex 2LZP polyimidazoline compound ex Sandoz of Formula I and a naphthalene peridicarboxylic acid imide ex Bayer (as described in DE 3535496 of Formula II). Other quenching agents are described in EP 217256. where R is CH 3 in Cartarex 2L or H in Cartarex 2LZP The amount of quenching agent to be employed in the invention is preferably from 0.05 to 20% by weight of the composition most preferably from 0.1 to 10%. The compositions used in the invention can contain one or more active materials, selected from cationic, nonionic, zwitterionic and amphoteric fabric softening materials. Nonionic materials are especially useful in the context of the present invention. Suitable fabric softening compounds may for instance be selected from cationic fabric softening materials and nonionic fabric softening materials. Suitable materials include substantially water-insoluble quaternary ammonium compounds such as for instance disclosed in EP 89200545.5 and EP 239 910, amine materials, amphoteric fabric conditioning materials as disclosed in EP 89200545.5, clays, polysiloxanes as disclosed in EP 150 867 (Procter and Gamble Co.) and nonionic cellulose ethers as disclosed in EP 213 730 (Unilever). The effective amount of the fabric softening compound or compounds used in the present invention is generally in the range of up to 50%, preferably up to 40% by weight, most preferably not more than 30% by weight of the composition. The level is above 1%, more preferred more than 2%. The compositions may be in any convenient form such as bars, powders, pastes or liquids which may be aqueous or non-aqueous and structured or unstructured. The fabric softening agent may be incorporated as such or it may be incorporated in the form of particles. The quenching agent may be incorporated in liquid or solid form. For use in the rinse cycle of the fabric laundry process, the compositions are preferably liquid and comprise an aqueous base, which may constitute from 5 to 97% by weight of the composition. The pH of fabric softening compositions for use in the rinse is preferably less than 8.0 when added to water at a concentration of 1% by weight of the composition. The invention will now be illustrated in the following non-limiting examples. EXAMPLES Example 1 Samples of mercerised cotton calico were taken and dyed with 0.75% by weight of Anthrasol pink IR (ex Hoechst). Where appropriate the pink cotton was 'damaged' by washing with a heavy duty domestic main wash powder - Persil Automatic which comprised 0.3% Tinopal DMS fluorescer. The wash conditions were tergotometer (100rpm) at 40°C for 30 minutes in 18°hard water using a cloth to liquor ratio of 1:40. Rinsing was also carried out in a tergotometer using a cloth to liquor ratio of 1:40. The fluorescence of the samples was calculated by measuring reflectance from the samples at 460nm using an Elrepho-reflectometer with and without a UV filter on the incident light. The fluorescence (F) is then the difference between these reflectance values. Samples of pink, fluorescer damaged cotton were treated with a 2.8g/l aqueous solution of a typical rinse conditioner formulation to which various levels of quenching agent were added. The treatment was carried out at 25° for 10 minutes. The formulation was as follows: Parts by weight Arquad 2HT 4.8 Fatty Acid (Pristerine 4916) 0.5 Water 93 Isopropanol 1.2 Orthophosphoric Acid 0.018 Sodium Chloride 0.01 Perfume 0.23 Minors 0.0737 Level of Quenching Agent g/I F Value Cartarex 2L Formula I Quenching Agent Formula II 0 13.5 13.5 0.05 6.7 2.6 0.5 4.4 - 0.75 3.9 - 0.8 - 0.8 These results show that use of compositions according to the invention reverses the effect of fluorescent agent damage on fabrics.

Claims: Use of a fabric or textile treatment composition in the rinse step of a fabric laundering process, to restore original colour and/or prevent changes in hue caused by fluorescent agents, characterised in that the composition comprises : (i) from 1 to 70% by weight of a water insoluble fabric softening material; and (ii) from 0.01 to 60% by weight of a quenching agent. The use as claimed in claim 1, wherein both the quenching agent and fabric softening material are cationic. The use as claimed in claim 1 wherein the water insoluble fabric softener is a quaternary ammonium material. The use as claimed in claim 1, wherein the composition comprises from 1% to 50% of a quaternary ammonium material. The use as claimed in claim 1 wherein the quenching agent is cationic. The use as claimed in claim 1 wherein the composition comprises from 0.01 to 60% by weight of quenching agent.

Inventors: CLEMENTS ANTHONY HENRY, CLEMENTS, ANTHONY HENRY, CLEMENTS, ANTHONY HENRY, UNILEVER RESEARCH LAB.
Applicants: UNILEVER NV, UNILEVER PLC, UNILEVER N.V.
Application year: 1991
Main classification: C11D1
IPC codes: C11D3, D06M13, D06P5, C11D1