US1829522A - Detergents and in washing - Google Patents

Description

Patented Oct. 27, 1931 I UNITED STATES PATENT,- OFFICE HERBERT A. KERN OI HINSDALE, AND GAIL J. RINK, OF OAK PARK, ILLINOIS, AS- SIGNOBS '10 NATIONAL ALUIINATE CORPORATION, 01' CHICAGO, ILLINOIS, A COR- POBATION OF DELAWARE nmnonn'rs AND IN wnsnmo Ho Drawing.

The present invention relates to an improved process of laundering and also to products employed in laundering operations. The invention also has reference to the use 5 of sodium aluminate in known detergents and soaps for the purpose of enhancing and im roving their action.

ne of the objects of the invention is to produce a launderin solution comprising the usual form of soa ut carrying in addition a soap-aid in the orm of sodium aluminate.

The second object of the invention is so to act on laundering fluids containing soap to increase the alkalinity beyond that obtainable by soap alone, but to do so wh1le at the same time avoiding the destructive actlon of strong alkalies such as the caustic soda that is usually employed,

The third object of the invention is to no roduce in the laundering fluid a precipitated fioc which is peculiar y efl'ective in entangling and adsorbing particles of dirt, thus facilitating their removal and preventing their adherence to the surface of the I fabric being cleaned.

A further object isto produce a soft, slipper soap curd which is readily r1nsed off an does not tend to adhere to the surface of the fabric being laundered.

A further object is -to remove from the water any iron or manganese present, thus preventing spotting and discoloration of the fabrics undergoing cleaning.

Other objects and advantages w1ll appear in connection with the specification and c aim hereinbelow.

In practicing the present invention the ordinary soap solutions used in laundering have added thereto a certain amount of sodium aluminate, but the invention also contemplates the furnishing of a dry product consisting of an alkaline material and sodium aluminate or of a previously prepared solution that may be added to the wash liquors by the user.

The use of additional agents along with soap in commercial laundry practice is, of course, quite common. The materials usually added as soap-builders include caustic soda, soda ash, sodium silicate, tri-sodium phos- Application am September 12, 1929. Serial No. 392,262.

phate, ammonia and similar materials. The use of caustic soda is quite common, but sufl'ers some serious objections inasmuch as this chemical exerts a deleterious effect on the fabric being cleaned. For this reason the art of laundering has been searching for a material, which, while capable of increasing the alkalinity of the wash waters, would avoid the use of caustic soda or would at least enable less of it to be used so that the fabric would suffer less damage when undergoing treatment on thewash wheel, such as is customarily used in commercial laundries.

For a proper understanding of the invention it may be mentioned that good modern commercial laundry practice consists of the following steps:

The goods to be laundered, whether preliminarily soaked or not, are first subjected, usually for ten minutes, to treatment in a rotating wash wheel, with a solution containing soap and an alkaline material but only sufficient of the same to produce very weak suds and in some cases with just enough of the alkali and soap completely to soften the water and loosen the dirt. This preliminary treatment is known as the break water. Following this, and after removal of the break water by draining, the goods to be laundered are submitted to the first suds for ten minutes, then to a second suds for ten minutes, and then to a third suds for fifteen minutes to which bleach is usually added, after which the goods are rinsed five times, and it is only in the last or fifth rinse that any bluing is added. It is also customary in the fifth and final rinse to add an acid material, such as oxalic or acetic acid or the acid fluorides, in order to insure removal of the residual soaps that may have been precipitated on the fabric and to insure removal of all alkalinity.

It is to be understood that the rinsings referred to are each of five minutes duration and are preferably carried out with soft water, and which may comprise the use of distilled water. The rinsing effects the removal of the alkali which should progressively become less, and the rinse water after the final bluing and souring should show no alkalinity to phenolphthalein and only slight alkalinitiy to methyl orange, the specific value depen ing upon the alkalinity of the water used for rinsing. The pH of the water from the final7rinse and sour should be slightly below It should. also be mentioned that solutions of sodium aluminate are alkaline and do not react with soa to form insoluble aluminum soaps, as woul be the case if alum or an acid compound of aluminum were employed. In sodium aluminate the aluminum is in the negative radical or an ion and does not react, as above stated, with soaps.

In the experimental work which was done prior to the perfection of the invention a arge number of ex riments and demonstrations were made. t was found that sodium aluminate when added to soap solutions in proportions of 15 to 25 pounds of sodium aluminate to every 100 ounds of soap increases the alkalinity oi the solution, and analogous effects are produced when said aluminate is added to solutions of soda ash or of mixtures of soap and soda ash. In no case, however, is the total alkalinity the sum total of the efiect of each of the alkaline compounds when in the same volume of solution, thereby indicating that the dissociation and hydrolysis of some or all of the comounds are repressed by the presence in soution of one or more of the other compounds.

The tests hereinbelow described were made in a commercial laundry. A commercial sodium aluminate containing 10% of sodium hydroxide was employed and a water softened by a zeolite softener was used. This water had a hardness of 0.9, an alkalinity toward phenolphthalein of 0.0, and an alkalinity toward methyl orange of 25.1, all exressed in grains per gallon of calcium carnate. The soap batches were made up in lots of 450 gallons, containin in all 150 pounds of soap, the mixture ing heated with live steam until the soap was in solution. Then the necessary soap builder was added and the volume corrected to 450 gallons. The soap solution required for the actual wash wheel was drawn from this suply tank. The following mixtures were used in the test:

1. 15 pounds sodium aluminate, 20 pounds tri-sodium phosphate, pounds soda ash, 100 pounds soap.

2. 25 pounds sodium aluminate, pounds soda ash, 150 pounds soap.

3. 15 pounds dry sodium aluminate, 85 pounds soda ash, 1.00 pounds soap.

(4;. 150 pounds soap, 40 pounds dry caustic so a.

The washing practice was approximately that described above. Only a sufi'icient quantity of the soap solution was added to the break water to give very light suds or just short of suds but enough of the solution being added to the first, second, and third suds waters to produce a running suds.

In the hereunto appended table the results are given of the titrations of the various break, suds and rinse waters at the end of the washing or rinsing period. The columns headed P refer to the alkalinity of these waters to. phenolphthalein and the columns headed M refer to the alkalinity to methyl orange, both expressed in terms of grains per gallon of calcium carbonate. The columns headed pH refer to the hydrogen ion concentration of the solution.

Tabulation of average P. and M. and pH readings found on suds and rinse waters at the end of the washing or P-Alkalinity to phenol hthalein M-Alkalinity to methy orange }Ex,pmssed as gnu-n5 per gallon rinsing period of calcium carbonate.

Washing time. 10 min. 10 min.

10 min.

16 min. 6 min. 5 min. 5 min. 5 min. 8 min.

Break Hi0 1st suds 2nd suds 5th-blue and sour rinse Bleachand 3rd suds 4th rinse 1st rinse 2nd rinse 3rd rinse pH pH pH! M pH pH Soda Ash, tri-sodium phosphate,

aluminate mix.

1. 460 gals. H10

150lbs.soa

1501b ii iu o S. BI l 4 66%soda h Soda ash, sodium aluminate mix.

150 be. soa

0 C.P.dry NBiAliO4 2. 8 13.25 9. 2 4. 0 14. 9 9. 7 3. 8

Soda ash, sodium aluminate mix.

3. 450 gals. H20 150 lbs. sea

85 soda ash 1601bs.

G.P.dry NBAIIO 18. 2 9.6 5.1 18.3 9. 5 4. s

Caustic soda mix.

4. 450 gals. H10

150 lbs. soap 40 lbs. dry NaOH 7 It will be noticed from the table herein reproduced that composition No. 3, containing 85 parts of soda ash and 15 parts of chemically pure dry. sodium aluminate yielded the most satisfactory results, which were particularly noticeable in that the hydrogen ion concentration in the break water was lower than even with the use of caustic soda, namely, pH 9.6 as against pH 9.4:. Despite the fact that allthe way through the titrations with the sodium aluminate and soda ash showed greater alkalinity, yet nevertheless in the final rinsing the alkalinity was less than with the caustic soda, and the hydrogen ion concentration was just above the neutral point, namely, at pH 6.2. When using mixture No. 2 containing 7 5 parts soda ash and 25 parts of chemically pure dry sodium aluminate, the pH of the break water was 9.2 and after final rinsing was 6.1. The other figures are practically self-explanatory and would readily be understood by any one skilled in this art. They show, among other things, that the total alkalinity as determined by methyl orange is usually greater when using sodium aluminate mixtures with soda ash but nevertheless the causticity of the solution, that is to say, the deleterious effect on the fabric, is very much less marked. The particular advantage found in practice was that the soap appeared to form a much softer curd which was so slippery that it readily rinsed off and did not attach itself to the goods. This is a very important factor in commercial laundry work as it makes for cleaner finished goods with less tendency toward graying and also cuts down the requirement of acid in the souring rinse. An additional advantage lies in the fact that during the suds stage the dirt is more readily loosened from the fabric, and by reason of formation of alumina floc which entangles the dirt, prevents the settling back of the loosened dirt upon the fabric.

If the water contains iron or manganese usually the soda ash or caustic soda added will cause precipitation of the iron or manganese, at first in colloidally dispersed form, which, however, readily attaches itself to the fabric producing brown or yellow stains which are virtually impossible to remove. When, however, sodium aluminate is present the iron or manganese is immediately precipitated in the form of loose floc which shows no tendency to precipitate upon the fibres. This is a very important point and contributes materially to the advantages derived from the practice of the present invention.

While we have described herein the use of sodium aluminate, it is of course to be understood that other soluble aluminates such as potash and ammonia are to be construed as equivalents. The type of sodium aluminate also is not limited and may comprise either the dry sodium aluminate or solution of sodium aluminate containing added caustic soda as a stabilizing agent. I

In the hereunto appended claim the term sodium aluminate is intended to comprise both the tri-sodium aluminate (Na AlO as well as the meta aluminate (Na Al O What it is desired to protect by Letters Patent of the United States is the following: Process of preventing the adherance of precipitates of manganese and iron hydroxides to fabrics when laundering the latter which comprises adding to the laundering fluid a composition containing 85 parts of soda ash and 15 parts of sodium aluminate.

In witness whereof, we have hereunto subscribed our names.

HERBERT A. KERN.

GAIL J. FIN K.