US2044467A - Cleansing preparation - Google Patents

Description

Patented June 1 1936 2,044,467 CLEANSING PREPARATION Theodore K. Cleveland, Drexel Hill, Pa., assignor to Philadelphia Quartz Company, Philadelphia, Pa., a corporation oi. Pennsylvania No Drawing. Application May 27, 1931,

Serial No. 540,497

sclaims. (Cl. 87-5) This invention relates to certain new preparaof different compositions which are dissolved and tions for cleansing operations as well as to a new used for cleaning purposes before their respective method of cleaning, and the principal objects as constituents have come to a state of equilibrium. well as the chief advantages of the invention will This temporary state of non-equilibrium is char- 5 be more clearly understood if the following brief acteristic of almost all systems in which two dif- 5 reference to the state of the art is first presented. ferent soluble silicates are mixed although it is It is at present recognized in the industries that obvious some combinations are more useful than many of the customary commercial soluble siliothers. It has not heretofore been realized that cates exert a distinct protective eifect in consuch combinations are useful because the art has trolling corrosion. This is particularly true of the always assumed that a mixture of two or more 10 more silicious grades of the customary liquid silisilicates would yield a solution having a set of cates and the protection afforded is generally atproperties intermediate between the properties tributed to the formation of colloidal films on the of its components or that the different propersurface to be protected, thus preventing access ties of the respective silicates entering into the 0f the attacking agent. As examples where this mixture would unfavorably modify one another, 15 protective eifect has been utilized, there might be or, stated in other Words, would defeat the purmentioned the introduction of soluble silicates pose for which the others were used. into water heating systems or into iron or lead Therefore, among the objects of my invention municipal water distributing systems, etc. Small may be cited the'following:

amounts have also been added to shaving soaps. The provision of mixtures of alkali metal sili- 20 0 Creams, which are marketed in metal cates for cleansing purposes in which the proptubes. erties of the diiferent silicates. are employed si- Furthermore, less silicious silicates such as somultaneously in the same solution; the provision m m a i t a ara d y a mu h of a detergent mixture of the character described higher eii'ective alkalinity, as well as byvariations the action of which may be nicely regulated and 2 in their ability to cause deflocculation, emulsificapredetermined to suit the particular requirements tion, and the like. of the contemplated cleansing operation; the pro- In detergent practice, such factors astime, temvision of cleansing mixtures which will have all D Concentration, degree o agi a n, etc of the advantages of strongly alkaline constituall have their eifect, and each industrial cleanents while at the same time embodying the pro- 30 ing operation presents a complex of such factors tective characteristics of the more silicious siliso that the choice of the detergent best suited to cates; the provision of dry soluble mixtures of the particular operation in hand, is a. matter of alkali metal silicates of high RzOzSiOz ratio with some nicety. A alkali metal silicates of low R2O: Si0z ratio where However, even with present knowledge on this R20 refers to the oxide of an alkali metal; and, 35 subject, it is often difiicult to arrive at a choice in general, the provision of detergent mixtures which is altogether satisfactory. For example, of the alkali metal silicates which are adapted certain cleansing operat ons may require a silifor use in cleaning a wide variety'of surfaces and cate of extremely active detergent characteristics, materials such as wood, paint, concrete, stone,

0 and, therefore, one of high alkalinity. Such a glass, metals, fibers, textiles, and the like without silicate may very well injure the article or subin any way injuring them while at the same time stancewto be cleaned. At the same time a siliemploying whatever degree of alkalinity may be cate of less active characteristics may not yield necessary or advantageous in obtaining the optithe degree of cleansing which is most desirable. mum degree of cleansing action,

Under circumstances such as these, a compro- The foregoing, together with such other ob- 45 misc is -generally resorted to, a silicate of interjects as may appear hereinafter or are incident mediate composition or characteristics being to my invention, may be obtained, by way of 11- adopted. lustration, according to the following example:

I have found, however, that it is possible to pre- Sodium metasilicate pentahydrate,

pare a cleansing solution in which is combined Nd SiO JiH O the desirable features or characteristics of high s l bl diu ili t h alkalinity and great detergent effect with the proximating;

protective characteristics so necessary in many industrial cleaning operations. I obtain my improved results by preparing mixtures of silicates 10 lbs. 50 ving an analysis apfor the more silicious In the above formula, the NaaOiSlOa weight percentage ratio for the metasilicate is 1:0.9'7; silicate, 1:322; and for the mixture of silicates, 111.88. The more silicious silicates should be in the form of a flne powder free from lumps. in the customary form available on the market, most of which will pass the U. S. Bureau of Standards 14 mesh screen or even coarser although I prefer to use it in finer form or to grind the two silicates together during or after mixing, thus preventing the tendency for the mixtuie to separate into coarser and finer fractions. The product is ready for use as a finely comminuted dry mixture by whatever method prepared. This particular mixture is adapted to be put into solution in warm or hot water and used at once, but it is obvious that similar results can be had by mixing the appropriate solutions immediately before use. The example is particularly adapted to such type of service as removing oils, buffing or polishing compositions, milk products, etc., from soft metal surfaces such as lead, tin, copper, nickel, aluminum, or alloys thereof, or from textiles, wood, etc.

As an example of a mixture in which the action of alkali is still further restrained, I cite the following:

y Soluble sodium disilicate, of composition ap- 'proximating:

I Per cent lbs. --l7.5 Soluble sodium silicate of composition approximating:

Per cent N550 19.4 SiO- 02.5 ..10 lbs. H:O.--..-.-. l8.l

An intimate powdered mixture is'to be made which may he put into solution in warm or preferably hotwater and used immediately after dissolving.

. cate of relatively low alkali oxide:

.gether with a more It is apparent that a series of mixtures each of which comprises basically an alkali metal silisilica ratio toalkaline alkali metal silicate, can be produced in which from one mixture to the next, the regulated, either through change to silica ratio of one or both in alkali dxide of the constituents,

orby alteration of the relative proportions of" constituents used in a given mixture. Such a series of mixtures would be much more widely adaptable to practical problems as they arise than any single silicate.

It should be emphasized further that the property of protective action coupled with high activity of alkali which such mixtures exhibit,

gradually diminishes after the mixture is put into solution due to rearrangement between the'silicates. In time the properties of the mixture in solution become those of a silicate of their aggregate composition and the NazO1SiOz ratio. Such a single silicate might have been separately prepared and put into solution directly but the advantages which are features of this invention would not be developed. Heating speeds the rearrangement. The most desirable combination of properties is to be expected ordinarily in freshly prepared solutions. Old solutions cannot be expected to be as effective either in action or protection, even though unused.

The metasilicate may be used of soluble silicates with zinc, etc.,'

intensity of action may be intermediate I wish to point out also that although this invention has been developed around the use of sodium silicates, alkali metal silicates as a class have been mentioned heretofore-and may serve the purposes of the invention equally well although, of course, proper allowances are to be made for the individual differences of the specific silicates to be employed.

The combination of the more alkaline types silicious materials not soluble in water but yielding colloidal silica in contact with alkaline solutions may produce washing solutions not in equilibrium, which are the full equivalent of the silicate mixtures heretofore described. Sodium metasilicate and infusorial earthgtripoli, opaline or other hydrous forms of silica will yield such solutions. 'They may even be obtained from hydrous clays or other insoluble silicates.

The invention contemplates added materials such as abrasives, caustics, soaps,-saponin or other materials which may lend additional desirable characteristics to the products of the invention either for general or specific uses. Powdered rosin may be added in small amounts, which will readily dissolve in the alkaline solutions to form a soap. I

It should be pointed out that while I prefer to prepare my improved mixtures in the form of a dry powder, yet this, of course, to obtaining the advantages of the invention as it is quite possible to prepare independent solutions and then bring them together or to add a powder to an already prepared solution. In short, the precisemanner in which the materials are mixed is not important, although, as stated, I prefer to provide dry 'mixtures containing the properproportions of the ingredients desired which can be made ready for use simply by dissolving them in the proper quantity of water.

I also wish to direct attention to the fact that while in most instances the combination of two silicates will be suiilcient, yet, it is quite possible to combine more than two should occasion demand.

In conclusion, I should like to say that it is well known that silicates which contain more than two molecules of S102 for each R10 yield solutions characterized by the presence of silica in a colloidal state, and it is believed that this is an important factor in detergent action. Sodium metasilicate and the more alkaline silicates, however, are crystalioidal in character but have useful properties associated with their high alkalinity. It has not heretofore'been known that these advantages could be combinedin one solution. The range of composition of individual components of .these mixtures may extend from sodium hydroxide at one extreme to silica on the other.

As a consequence of the high proportion of silica and of buffering and colloidal action induced, the more silicious silicates say, possess pH values lower than shown by metasilicate or disilicate solutions of equivalent NazO concentration. It follows in general that the acfurther the use of is-not essential are less alkaline, that is to ful alkaline action in cleaning or other operations eyen at the risk of some weakening of flber, etching or other attack. It is to such operations that the present invention is particularly directed in intermediate between the ratios of the constituent silicates, structural equilibrium between the two to give the properties of a single silicate of the said intermediate composition when put into solution is only slowly attained, each constituent silicate exhibiting in considerable degree and for a period of time the desirable properties for which it was chosen as a component of the mixture. Thus to cite a case, it becomes possible to clean polished aluminum articles with such mixtures and without etching, under conditions and with satisfaction which would not be attainable were either component used singly. The less alkaline silicate would be found inefilcient in cleansing action; the more alkaline silicate too strong and likely to ruin the finish. ,In the mixture the restraining action exerted permits the use of higher temperatures riods under treatment, or in other cases permits the period in contact with solution to be increased as dictated by convenience, for sterilization or for other reasons.

What I claim is:

1. As a new composition of matter, a dry mix-" with water disperses to form a colloidal silicious system.

and correspondingly reduced pe-' 2. A detergent composition of matter comprising a physical mixture of a crystalline hydrated sodium silicate and a second sodium silicate which disperses in water to form a colloidal silicious system, the relative proportions of said silicates being such as to yield in aqueous solution a detergent bath partaking of the individual characteristics of the said silicates and adapted to be used before equilibrium is attained.

3. A detergent composition of matter comprisl0 ing a physical mixture of a crystalline hydrate of sodium metasilicate and a second sodium silicate which disperses in water to form a colloidal silicious system, the relative proportions of said silicates being such as to yield in aqueous solution 15 a detergent bath partaking of the individual characteristics of the said silicates and adapted to be used before equilibrium is attained.

4. A detergent composition of matter comprising a physical mixture of crystalline sodium disili- 20 cate and a second sodium silicate which disperses in water to form a colloidal silicious system, the relative proportions of said silicates being such as to yield in aqueous solution a detergent bath partaking of the individual characteristics of the said 25 silicates and adapted to be used before equilibrium is attained.

5. An aqueous cleansing solution comprising the composition of claim 1.

6. An aqueous cleansing solution comprising the 30 composition of claim 2.

7. An aqueous cleansing solution comprising the composition of claim 3.

8. An aqueous cleansing solution comprising the r composition of claim 4.

momma: x. cmvnmn'n.