US2616855A - Detergent composition - Google Patents

Description

, radiations. stance, as ultraviolet filters in photography, in

variety of products,

acids) fiatentecl Nov. 4, 195? UNITED STATES gP'lENT OFFICE DETERGENT COMPOSITION Charles E. Wheelock, Cincinnati, Ohio, assignor to The Procter and Gamble Company, Ivorydale, Ohio, a corporation of Ohio No Drawing. Application January 15, 1948,- Serial No. 2,544

4 Claims. (01. 2'52 117) 1 This invention relates to detergent products having an alkaline reaction and containing whit- :ening (or color brightening) agents of a fluorescent nature.

Coumarin derivatives, particularly beta methyl "umbelliferone (4 methyl 7-hydroxycoumarin) have found a'variety of uses which take advantage of their abilities to absorb ultraviolet radiations and to emit fluorescent radiations in the blue end of the visible spectrum, and which are in part dependent also on the color-free characterof many of these derivatives when viewed in visible light which is free from ultraviolet Such compounds are used, for insuntan lotions, and in transparent wrappers for perishable foods, as optical bleaches to improve th whiteness of paper and textiles, as

whitening agents in off-white soaps and other substances, and as color brightening agents in a The present invention concerns the incorporation of a selected group of carbostyrils (which may be thought of as coumarins in which an NR group has replaced the heterocyclic oxygen atom) as whitening or brightening agents in compositions having at least a mildly alkaline nature, and particularly in subbstances' of this character which are processed, after the addition of the fluorescent material, at elevated temperatures. Among such compositions are ordinary soaps (alkaline metal salts of the higher fatty washing compounds containing such soaps, and washing compounds containing both synthetic organic detergents and alkaline inorganic salts such as alkaline phosphates, polyphosphates, carbonates, silicates, and borates.

The manufacture of detergent compositions of this character frequently includes mixing and/or otherwise processing the ingredients while in molten condition at temperatures which may range from about 140 F. to as high as 450 F., sometimes in the presence of small amounts of .free sodium hydroxide which is, as' a rule, subsequently neutralized.

acterized by their highrsolubilityin water, their,

resistance to precipitation by theconstituents 7 Beta methyl umbelliferone and the other 2 of hard water, and their surface active and eifective detergent properties, such as water-soluble salts of sulfuric and phosphoric reaction products of alkyl and substituted alkyl compounds containing from 8 to 18 carbon atoms in the alkyl group; and all of the non-ionic detergents which are similarly characterized by high solubility in water, resistance to precipitation by the constituents of hard water, and surface active and elfective detergent properties, such as the reaction products of higher alcohols and higher fatty acids with considerable amounts of alkylene oxides. Numerous examples of such detergentsare mentioned in Linds U. S. Patent No. 2,396,278. The nature of the soap or synthetic detergent employed in making the compositions of the present invention is not critical insofar as concerns compatibility with the alkali-stable class of carbostyrils defined herein. These carbostyrils are compatible with any and all known soaps and synthetic organic detergents, whether anionic, nonionic, or cationic, and may advantageously be used to whitenall such detergents.

The outstanding benefits of the invention are however realized, as will appear, in detergent compositions of an alkaline nature, and in the formation of such compositions one tends to avoid using detergents which lack alkali stability, such as some of the cationic detergents-which are hydrochlorides.

coumarin derivatives'which have commonly been recommended as whitening or brightening agents are unstable in alkaline media, particularly at elevated temperatures, and their use in soaps and other detergent compositions of an alkaline nature is therefore greatly restricted. Some soaps are processed at comparatively low temperatures during and after the step of incorporating minor ingredients such as perfumes, preservatives, coloring matter, and fluorescent whitening or brightening agents, and in these soaps the unstable fiuorescent agents may perhaps be used with at least temporary effectiveness. Even in such cases, however, discoloration difficulties are prone to occur when the soap is exposed to sunlight or when packing scrap is remelted, because the decomposition products produced by the attack of alkali on unstable fluorescent materials .3 such as beta methyl umbelliferone are frequently highly colored compounds.

Objects of the invention are to provide soaps, soap compositions, and alkaline soap and/ or synthetic detergent compositions generally, which have been whitened or brightened by the incorporation of alkali-stable blue fluorescing compounds, and which will not lose appreciable fluorescence with age, or discolor in sunlight or upon remelting.

Another object of the invention is to provide heat processed detergents of alkaline reaction which are whitened or brightened by the incorporation of fluorescent carbostyrils which are stable to alkalies under severe processing conditions.

Another object is to provide soap bars, granules, and flakes, and similar solid form products made from synthetic detergents in conjunction with alkaline materials, having improved whiteness by virtue of the incorporation of heat-stable and alkali-stable normally colorless compounds which in sunlight fiuoresce in the blue end of the spectrum.

Another object is to provide detergent compositions (including soaps processed at low temperatures) of more permanent whiteness, due to the inclusion of blue fluorescing substances which do not gradually lose this fluorescence in mildly alkaline media at ordinary temperatures, and particularly upon prolonged exposure to sunlight.

The general terms blue-fluores-cing, or fluorescing in the blue end of the spectrum, unless specifically applied to some one chemical compound,

are used to designate fluorescence in the violetblue-green region of the visible spectrum.

The essential whitening (or brightening) agent of the whitened (or brightened) detergent compositions of my invention is a oarbostyril having the general formula in which each R may be hydrogen or an alkyl or aralkyl group containing not over carbon atoms, R' is hydroxy, amino, mono- .or dialkylamino, monoor di-alkylolamino, or heterocyclic .amino, said B group in no case containing more than 6 carbon atoms, and R. is hydrogen or methyl.

Representative of this class of alkali-stable blue-fiuorescing compounds, when using the followingsystem of numbering are the following typical compounds, all members of this class being suitable for use in the 'invention:

1,4- dimethyl-'I-hydroxycarbo'styril 4-methyl-7 -hydroxycarbostyril 4-methyl -7-aminocarbostyril 3 -propyl-4methyl-7-hydroxycarbostyril 4-methyl-7 -diethanolaminocarbostyril 4-benzyl-7 diethylaminocarbostyril 7 -piperidinocarbostyril 3;4-dimethyl-'7 '-hydroxycarbostyril.

4 The following tautomerism is possible in many of these carbostyrils and either one or both tautomers are considered to be within the scope of the invention:

These carbostyrils are remarkably superior to analogous coumarins (at least to those having no alkyl group in the 3 position) in the permanence of their characteristic fluorescent behavior in alkaline media. This is illustrated by the following typical data, measured under carefully standardized test conditions.

which indicate the stability ofthe fluorescence'in a saturated alcoholic solution of caustic potash, are much more drastic than any conditions met in the manufacture of commercial detergent products. Comparisons under more practical conditions are given in connection with following examples of the invention.

Example 1 (a) To a quantity of molten kettle soap at a temperature of about 200 F., the soap being'sodium soap of the fatty acids of coconut oil and tallow of good quality, was added with stirring 0.002% by weight of 4-methyl-f7-hydroxycoumarin .(beta methyl umbelliferone, .an alkali-unstable blue fluorescer) idissolved'in about .ten times its weight of essential oils'perfume. Asmall sampleof the soap was promptlyiremoved 'and quickly solidified by cooling. The main mass of soap was heated to 435 F. under sufiicient pressure to prevent steam formation, and was then quickly released into a flash'dryingchamber. A sample of the flash dried soap, which had now lost between one third and one half of itsoriginal moisture content, was removed and quickly solidified by cooling.

(6) Another lot of the same soap was similarly processed, except that an equal amount of 4- methyl-'T-hydroxycarbostyril was substituted in place of the corresponding unstable derivative used in (a).

(0) Another lot of the samesoap' was :similarly processed, except that this time 0.0025% by weight of 4-methyl-7aminocarbostyrilwas used as the fluorescer.

(d) Another lot of the same-soapw'as similarly processed, except that' to Kit n'o fiuorescing compound was added,

Examination and testing of the'samples'from these four lots of soap showed the following:-

- In the above exampl es one may satisfactorily replace the 4-methyl-7-hydroxy- (or 'T-amino) r (a) (b) (c) A a Fhmesc Used 4-OHa-7-OH-coumarin 4-OHa-7-OH-carbostyril 4-OHs-7-NH2-carbostyril None Appearance of fresh sam es:

" (1) Before flash drying- In daylight. Whiter than Whiter than Whiter than (d) -Yellowish cast. In ultra-violet Bluish-white fluorescence. Strong violet-whitefluores- Strong decp violet fluo No fluorescence.

light. cence. rescence. (2) After flash dryv in daylight... Slight pink discoloration... Whiter than (d) Whiter than (d). Yellowish cast. In ultra-violet Faint brown fluorescence Greenish-whlte fluores- Strong violet fluores- No fluorescence.

1i t. cencc. cence. Appearance of aged 7 samples:

"(1) Before flash dry- Much of whiteness and l ing. 1 fluorescence gone. No discoloration. Some N discoloration N 0 ap p r e c i ab 1 e (2) After flash dry- Discolored andnearly all loss of fluorescence. Slightly whiter than ((1). change.

ing. fluorescence gone. Very slight loss of fluorescence.

The aging referred to in the above table comprised holding the sample for 7 hours at 80 F. under strong ultraviolet light, this being equivalent to about 2 days exposure to summer sunlight.

Example 2.-As another example, 0.10% by weight of 4-methyl-7-hydroxycarbostyril is incorporated, as a solution in a perfume made of a mixture of essential oils, in a molten well mixed mass consisting of 70 parts of laundry kettle soap and 30 parts of aqueous sodium silicate solution. This mixture is heated to about 180-225 F. and forced through atomizing nozzles into the upper portion of a spray drying tower where it encounters a stream of gases having a temperature of about 300 F. The resulting laundry soap granules are very noticeably whiter than a corresponding product containing no added fluorescing material, and this improvement in whiteness is retained undiminlshed during a prolonged period of storage under summer warehouse temperature conditions.

Example 3.-As another example, 0.01% by weight of 4-methyl-7-aminocarbostyril is incorporated, as a solution in alcohol, in a molten white kettle soap to which is also added minor proportions of perfume and preservative. The mass is introduced into the hopper of a water cooled soap roll, upon the surface of which a film of the soap was converted to plastic condition. This film was cut into ribbons, which were peeled off the cooling roll and fed into a soap flake drying chamber. The resulting soap flakes or chips appear decidedly whiter in daylight than similar soap flakes containing no blue fluorescing material. This improvement in whiteness persists in- Example 4.As another example, to a 10,000 pound batch of liquid slurry containing 4160 pounds of water, 1160 pounds of a mixture of sodium salts of sulfated higher alcohols derived from coconut oil and sodium salts of sulfonated alkyl benzene (the alkyl groups being predominantly tetrapropylene), 990 pounds of sodium sulfate, 3240 pounds of sodium tripolyphosphate, and 4.50 pounds of miscellaneous minor ingredients, is added while agitating the batch 0.007% (0.7 lb.) of 4-methyl-7-aminocarbostyril. The slurry, heated to about 160 F., is pumped to atomizing nozzles at the top of a spray drying tower through which heated air is circulated. The resulting detergent composition, in granular form, has an enhanced whiteness in daylight which persists indefinitely under normal conditions of storage, shipment, and use.

carbostyrils with any other carbostyril having the aforementioned general structural formula. Frequently one may wish to adjust, within the broad limits mentioned in the following paragraph, the percentage used so as to make allowance for differences in the fluorescence intensities of the different compounds. Some of these are Weaker and some are stronger than the intensities of the particular compounds used in the foregoing examples. In addition to variations in intensity, slight differences in the hue of the fluorescent radiation are caused by changes in the structure of the molecule.

In general, the amount of alkali-stable blue fiuorescing carbostyril which may most advantageously be incorporated in detergent compositions lies between about 0.0005% and 0.25% by weight, depending on such factors as the natural color and physical form'of the untreated detergent composition, the nature of its processing, the fluorescent intensity and hue of the brightening agent used, and the amount of whitening or brightening desired. Under conditions most frequently encountered the amount of brightening agent used will normally be between about 0.001 per cent and 0.10 per cent.

Methods of synthesizing the alkali-stable carbostyril derivatives used in the invention may follow known practice. 4-methyl-7-hydroxycarbostyril, for example, may be prepared by condensing meta-aminophenol and acetoacetic ester, as described by H. von Pechmann in Berichte 32, 3687 (1899), and von Pechmann and Schwartz in Berichte 32, 3700 (1899). After recrystallizing the product from alcohol it was found to have a melting point of 333-336 C.

Similarly, 4-"nethyl-7-aminocarbostyril may be prepared by condensing meta-phenylenediamine and acetoacetic ester, as described by Besthorn and Byvanck in Berichte 31, 798 (1898).

One may prepare 7-aminocarbostyril by condensation of ethyl oxalacetate and m-phenylenediamine, with subsequent saponification and decarboxylation (Kermack and Webster, J. C. S. 1942, 213-18).

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A solid form detergent composition of alkaline nature having an enhanced whiteness in sunlight, comprising essentially an alkaline detergent selected from the group consisting of (a) water soluble alkali metal salts of higher fatty acids, and (b) non-soap anionic synthetic organic detergents; and, in a proportion of from about 0.0005% by weight to about 0.25% by weight, carbostyrfl derivaitive having =the "structural'formu'la derimtme n-imethyb-fiehydmxycarbostml'.

3. The product of claim .1 in which .the .carwbostyril derivative is 4methy1-7-aminocarbostyril 4. "Theproduct of claim '1"in which'the detergent ingredient is sodium soap.

CHARLES WHEELOCK.

REFERENCES CITED The following references are .of record in the file of this patent:

FOREIGN PATENTS Number Country Date 522,672 Great Britain ,June 24, .1940 $567,716" Great Britain Feb. 28, 1945 731558 Feb. '11, 1943

Claims (1)

1. A SOLID FORM DETERGENT COMPOSITION OF ALKALINE NATURE HAVING AN ENHANCED WHITENESS IN SUNLIGHT, COMPRISING ESSENTIALLY AN ALKALINE DETERGENT SELECTED FROM THE GROUP CONSISTING OF (A) WATER SOLUBLE ALKALI METAL SALTS OF HIGHER FATTY ACIDS, AND (B) NON-SOAP ANIONIC SYNTHETIC ORGANIC DETERGENTS; AND, IN A PROPORTION OF FROM ABOUT 0.0005% BY WEIGHT TO ABOUT 0.25% BY WEIGHT, CARBOSTYRIL DERIVATIVE HAVING THE STRUCTURAL FORMULA