Use of a brightener pigment in cleansers or detergents
The present invention relates to the use of a brightener pigment, which comprises
(a) a cellulose powder which is dispersible in water, and
(b) a water-soluble fluorescent whitening agent for increasing the whiteness of cleansers or detergents.
A cellulose powder suitable as component (a) is, for example, microcrystalline cellulose which is obtained from cotton linters or wood cellulose, usually by a combination of hydrolytic degradation and mechanical wet crushing of the particles with subsequent spray-drying, and which no longer has a fibre structure (viz. "Umschau" 77 (1977), 312).
Also suitable are cellulose powders which are produced by dry grinding standard wood fillers and which likewise no longer have a fibre structure.
Particularly suitable cellulose powders are those having a high crystallinity of more than 30%, preferably of more than 50%, as well as an ability to reduce the hydrophilicity, and a dispersibility in water of up to a solids content of about 25.
Water-insoluble types of cellulose are also suitable, for example cellulose ethers, such as methyl- or ethylcellulose, or cellulose powders having a particle size of 25 to 35, preferably of 30 μm.
Fluorescent whitening agents suitable for use according to this invention and corresponding to component (b) conform to formula
R1 and R2 are each independently of the other -OH, -Cl; -NH2, -O-C^C^alkyl, -O-aryl,
-NH-C C4alkyl, -N(C C4alkyl)2, -N(C1-C4alkyl)(C1-C4hydroxyalkyl), -N(C C4hydroxy- alkyl)2, or -NH-aryl, morpholino, S-C^C^alky aryl),
R3 and R are each independently of the other hydrogen, C C4alkyl, phenyl or a radical of
formula //
R5 is hydrogen; Cl or SO3M;
R6 is -CN; - SO3M; -S(C1-C4alkyl)2; or S(aryl)2;
R7 is hydrogen; -SO3M; -O-C C4alkyl; -CN; -Cl; -COO-C C4alkyl; or CON(C C4alkyl)2;
R8 is hydrogen; -Chalky!; -Cl or -SO3M;
Rg and R10 are each independently of the other hydrogen; C^C^alkyl; -SO3M; -Cl; or -0-C1.C4alkyl;
R is hydrogen; or C^C^alkyl;
R12 is hydrogen; C C4alkyl; -CN; -Cl; -COO-C C4alkyl; -CON(C C4alkyl)2; aryl or -O-aryl;
M is hydrogen; Na; K; Ca; Mg; ammonium; mono-, di-, tri- or tetra-C^C^Ikyl ammonium; mono-, di- or tri-C^C^hydroxyalkyl ammonium; or ammonium which is di- or trisubstituted by a mixture consisting of C^C^Ikyi and C1-C4hydroxyalkyl groups; and n is 0; or 1.
C C4Alkyl is a branched or unbranched radical and is, for example, methyl, ethyl, propyl, isopropyl, n-butyl and may be unsubstituted or substituted by halogen, such as fluoro, chioro or bromo, CrC4alkoxy, such as methoxy or ethoxy, phenyl or carboxyl, C C4alkoxycarbonyl, such as acetyl, mono- or di-C C4alkylamino or -SO3M.
The compounds of formula (1 ) are preferably used in neutral form, i.e.
M is preferably a cation of an alkali metal, in particular sodium.
The compounds of formula (1 ) may be prepared under known reaction conditions by reacting cyanuric chloride with the corresponding aminostilbenesulfonic acids and with an amino compound which is capable of introducing an R group and with a compound which is capable of introducing an R2 group, Rj and R2 being as defined above.
Examples of the fluorescent whitening agents which are advantageously used in this invention are listed in the following Table 1 :
The fluorescent whitening agents used according to this invention and corresponding to the component (b) are preferably used in amounts from 0.001 to 1.0 % by weight, more preferably from 0.01 to 0.5 and, particularly preferably, from 0.01 to 0.5 % by weight, based on the entire amount of dispersible cellulose powder used. The fluorescent whitening agents can in this case be added to the dispersible cellulose powder as individual compounds or also in the form of mixtures consisting of several individual compounds.
In principle, the brightener pigment used according to this invention and comprising the components (a) and (b) can be used singly or also together with other pigments for brightening cleansers and detergents. Other pigments used may be, for example, talcum, titanium dioxide, aluminium oxide, aluminium hydroxide, zinc oxide, chalk or clays, such as kaolin.
The brightener pigment used according to this invention may be prepared in simple manner by dispersing suitable cellulose powders in water and charging them with one or more than
one of the above water-soluble fluorescent whitening agents.
Even at a low temperature, the brightener readily adsorbs to the dispersed cellulose powder, and the brightened cellulose powder shows no greying even at relatively high brightener concentrations.
The dispersions so obtained can contain customary anionic or nonionic dispersants, for example the salts of polycarboxylic acids, sulfated or non-sulfated higher alkanols or alkyl- phenol polyglycol ethers, lignin sulfonates, carboxymethylcellulose, hydroxyethylcellulose, and the like.
The amount of fluorescent whitening agent used depends on the amount of cellulose powder used in the brightener pigments employed according to this invention. Generally, amounts of up to 10 % by weight of active substance, based on the cellulose powder, may be used. Higher amounts do not produce any additional brightening effect as the greying limit is exceeded. It is preferred to use amounts in the range from 2.5 to 7 % by weight, based on the dry cellulose powder.
Dazzling white organic brightener pigments are obtained in which the fluorescent whitening agent is incorporated or to which it is adsorbed. These products are solid colloidal particles having an average diameter of 0.1 to 0.2 μm which are agglomerated to pigment particles having an average diameter of 3 to 20 μm.
The optically brightened pigments produced in this manner are excellently suitable for improving the whiteness (aspect improvement) of commercial cleansers or detergents.
After being prepared, the brightener pigment can be added immediately in disperse form to the cleanser or detergent.
The aqueous brightener pigment can also be processed to a powder by standard process steps, such as filtration or drying.
The brightener pigment used according to this invention is preferably usually incorporated into the cleanser or detergent by first slurrying the brightener pigment, with stirring, in water and then adding the corresponding cleanser or detergent with further addition of water. A creamy slurry is thus obtained which is then dried and sieved. This yields a cleanser or detergent having a particle size of about > 0.3 to 1 mm. in another embodiment of this invention, the optically brightened cleanser or detergent may be prepared by simple powdering with the brightener pigment. To this purpose, 0.5 to 20%,
typically 1 -10%, of brightener pigment, based on the component to be brightened, are mixed dry until the particles are coated with the pigment.
Suitable agents which may be treated according to this invention with the brightener pigment comprising the components (a) and (b) are cleansers or detergents in powdered or granulated form. The detergent may be composed of one or more than one granular component in the form of particles, at least one granular component being enriched with the brightener pigment.
Suitable detergents are preferably in granular form having a high bulk density. In addition to the brightener pigment, the detergent may contain further ingredients, for example surfactants, inorganic and organic builder substances, bleaching agents, substances which positively affect the oil or fat removability, greying inhibitors and, optionally, substances which enhance the solubility and rate of dissolution of the individual granular components and/or of all agents, textile softening substances, colourants and fragrances and also alkaline and/or neutral salts in the form of their sodium and/or potassium salts.
The cleanser or detergent treated in this manner is distinguished by a very high degree of whiteness which is substantially higher than when the organic white pigment and optical fluorescent whitening agent are added separately.
Another advantage of the cleanser or detergent thus enriched is that in the actual washing process the brightener pigment or fluorescent whitening agent does not contact the goods to be washed and is not absorbed by them.
The following non-limitative Examples illustrate the invention in more detail.
Example 1 :
12.5 g of a cellulose powder with 0.2 % of the compound of formula
are mixed with 25 g of standard washing powder (ECE). This washing powder consists of:
8.0 % of sodium alkylbenzenesulfonate
2.9 % of tallow alcohol tetradecanethylene glycol ether 14 EO
3.5 % of soda soap
43.8 % of sodium triphosphate
7.5 % of sodium silicate
1.9 % of magnesium silicate
1.2 % of CMC
0.2 % of EDTA
21.2 % of sodium sulfate
9.8 % of water
After the brightened cellulose powder has been incorporated, the whiteness of the powder is determined by the Ganz method using a DCI/SF 500 spectrophotometer.
The addition of cellulose powder increases the degree of whiteness of the washing powder to 163 (according to Ganz). Without such an addition, the washing powder has a degree of whiteness of 51 (according to Ganz).
A washing liquor is prepared consisting of 0.4 g of the above washing agent in 50 ml of drinking water.
10 g of bleached cotton are placed in the liquor and washed for 15 minutes at 25°C. The fabric is then rinsed, spun and ironed at 160°C. This washing process is repeated 5 times.
After washing 5 times, the degree of whiteness of the treated fabric samples is determined.
After washing 5 times, the fabric samples washed with the washing powder/cellulose mixture have a degree of whiteness of 106, which is substantially lower than if the compound (101 ) is not adsorbed to the cellulose powder.