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Patented June 15,. 1936 UNiTED ‘STATES PATENT: FFICE 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 preparations for cleansing operations as well as to a new method of cleaning, and the principal objects as well as the chief advantages of the invention will 5, be more clearly understood if the following brief reference to the state of the art is ?rst presented. It is at present recognized in the industries that many of the customary commercial soluble silicates exert a distinct protective eifect in con10 trolling corrosion. This is particularly true of the more silicious grades of the customary liquid silicates and the protection afforded is generally attributed to the formation of colloidal ?lms on the surface to be protected, thus preventing access 15 0f the attacking agent. As examples where this protective eifect has been utilized, there might be mentioned the introduction of soluble silicates into water heating systems or into iron or lead municipal water distributing systems, etc. Small 20 amounts have also been added to shaving soaps. - 001d Creams, 8150., which are marketed in metal tubes. Furthermore, less silicious ‘silicates such as sodium metasilicate are characterized by a much 25 higher eii'ective alkalinity, as well as byvariations in their ability to cause de?occulation, emulsi?cation, and the like. In detergent practice, such factors astime, temDenture, Concentration, degree of agitation, etc” 30 all‘ have their eifect, and each industrial cleaning operation presents a complex of such factors so that the choice of the detergent best suited to the particular operation in hand, is a. matter of some nicety. 35 A - _ of different compositions which are dissolved and used for cleaning purposes before their respective constituents have come to a state of equilibrium. This temporary state of non-equilibrium is char acteristic of almost all systems in which two dif- 5 _ ferent soluble silicates are mixed although it is obvious some combinations are more useful than others. It has not heretofore been realized that such combinations are useful because the art has always assumed that a mixture of two or more 10 silicates would yield a solution having a set of properties intermediate between the properties of its components or that the different proper ties of the respective silicates entering into the > mixture would unfavorably modify one another, 15 or, stated in other Words, would defeat the pur pose for which the others were used. Therefore, among the objects of my invention may be cited the'following: ' The provision of mixtures of alkali metal sili- 20 cates for cleansing purposes in which the prop erties of the diiferent silicates. are employed si multaneously in the same solution; the provision of a detergent mixture of the character described the action of which may be nicely regulated and 25 predetermined to suit the particular requirements of the contemplated cleansing operation; the pro vision of cleansing mixtures which ‘will have all of the advantages of strongly alkaline constitu ents while at the same time embodying the pro- 30 tective characteristics of the more silicious sili cates; the provision of dry soluble mixtures of alkali metal silicates of high RzOzSiOz ratio with alkali metal silicates of low R2O:_Si0z ratio where However, even with present knowledge on this subject, it is often di?icult to arrive at a choice which is altogether satisfactory. For example, certain cleansing operat ons may require a sili- R20 refers to the oxide of an alkali metal; and, 35 in general, the provision of detergent mixtures of the alkali metal silicates which are adapted for use in cleaning a wide variety'of surfaces and cate of extremely active detergent characteristics, 40 and, therefore, one of high alkalinity. Such a materials such as wood, paint, concrete, stone, glass, metals, ?bers, textiles, and the like without stancewto ‘be cleaned. At the same time a silicate of less active ‘characteristics may not yield employing whatever degree of alkalinity may be necessary or advantageous in obtaining the opti the degree of cleansing which is most desirable. ‘mum degree of cleansing action, ' silicate may very well injure the article or sub- ' in any way injuring them while at the same time Hi 45 Under circumstances such as these, a compromisc ise-generally resorted to, a silicate of inter- , - The foregoing, together with such other ob- 45 jects as may appear hereinafter or are incident mediate composition or characteristicsv 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- 50 pare a cleansing solution in which is combined the desirable features or characteristics of high ‘alkalinity and great detergent effect with the ‘protective characteristics so necessary in many industrial cleaning operations. I obtain my im 55 proved results by preparing mixtures of silicates Sodium metasilicate pentahydrate, NdzSiOgJiHzO ............................................. _. soluble Sodium silicate ha proximating; ' 10 lbs. 50 ving an analysis ap > 2 ’ - 2,044,467 I wish to point out also that although this in vention has been developed around the use of In the above formula, the NaaOiSlOa weight percentage ratio for the metasilicate is 1:0.9'7; - for the more silicious silicate, 1:322; and for the sodium silicates, alkali metal silicates as a class have been mentioned heretofore-and may serve mixture of silicates, 111.88. The more silicious the purposes of the invention equally well al silicates should be in the form of a ?ne powder though, of course, proper allowances are to be free from lumps. The metasilicate may be used ' made for the individual differences of the specific in the customary form available on the market, silicates to be employed. most of which will pass the U. S. Bureau of The combination of the more alkaline types Standards 14 mesh screen or even coarser al . of soluble silicates with silicious materials not 0 soluble in water but yielding colloidal silica in 10 though I prefer to use it in ?ner form or to grind the two silicates together during or after mix-l contact with alkaline solutions may produce ring, thus preventing the tendency for the mix-_ washing solutions not in equilibrium, which are tui‘e to separate into coarser and finer fractions. The product is ready for use as a ?nely com the full equivalent of the silicate mixtures here H Cl tofore described. Sodium metasilicate and in fusorial earthgtripoli, opaline or other hydrous minuted dry mixture by whatever method pre pared. This particular mixture is adapted to be 15 forms of silica will yield such solutions. 'They put into solution in warm or hot water and used at once, but it is obvious that similar results may even be obtained from hydrous clays or other insoluble silicates. can be had by mixing the appropriate solutions The invention contemplates 20 immediately before use. The example (is par ticularly adapted to such type of service as re ‘ further the use of ‘’ 3 l added materials such as abrasives, caustics, soaps,~saponin or other materials which may lend moving oils, buf?ng or polishing compositions, additional desirable characteristics to the prod milk products, etc., from soft metal surfaces such ucts of the invention either for general or specific as lead, tin, copper, nickel, aluminum, zinc, etc.,'1 ' uses. Powdered rosin may be added in small 25 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 fol lowing: 'proximating: I Per cent I It should be pointed out that while I prefer it is quite possible to prepare independent solu . < 21. _________________ amounts, which will readily dissolve in the alka line solutions to form a soap. to prepare my improved mixtures in the form of a dry powder, yet this, of course, is-not essential " to obtaining the advantages of the invention as _ yv Soluble sodium disilicate, of composition ap 30 25 lbs. tions 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 Per cent . proper- proportions of the ingredients desired N550 .......... “19.4 SiO02.5 ..10 lbs. which can be made ready for use simply by dis 40 H:O.--..-‘.-._'.-_l8.l solving them in the proper quantity of water. 40 An intimate powdered mixture is'to be made I also wish to‘ direct attention to the fact that which may he put into solution in warm or pref while in most instances the combination of two erably hot- water and used immediately after dis silicates will be suiilcient, yet, it is quite possible to combine more than two should occasion de ; solving. It is apparent that a series of mixtures each mand. ~ ‘ 45 of which comprises basically an alkali metal sili In conclusion, I should like to say that it is silica ratio to well known that silicates which contain more . cate of relatively low alkali oxide: than two molecules of S102 for each R10 yield .gether with a more alkaline alkali metal sili cate, can be produced in which from one mix solutions characterized by the presence of silica ture to the next, the intensity of action may be ' in a colloidal state, and it is believed that this regulated, either through change in alkali dxide is an important factor in detergent action. So to silica ratio of one or both of the constituents, dium metasilicate and the more alkaline sili orby alteration of the relative proportions of" cates, however, are crystalioidal in character but constituents used in a given mixture. Such a have useful properties associated with their high series of mixtures would be much more widely alkalinity. It has not heretofore'been known 55 adaptable to practical problems as they arise that these advantages could be combinedin one solution. The range of composition of individual than any single silicate. , It should be emphasized further that the components of .these mixtures may extend from --l7.5 , Soluble sodium silicate of composition approxi 35 mating: property of protective action coupled with high sodium hydroxide at one extreme to silica on activity of alkali which such mixtures exhibit, the other. 60 gradually diminishes after the mixture is put into - ' ' _ As a consequence of the high proportion of silica solution due to rearrangement between the'sili and of buffering and colloidal action induced, the cates. In time the properties of the mixture in more silicious silicates are less alkaline, that is to say, possess pH values lower than shown by meta solution become those of a silicate of their ag gregate composition and the intermediate . silicate or disilicate solutions of equivalent NazO NazO1SiOz ratio. Such‘ a single silicate might ; concentration. It follows in general that the ac have been separately prepared and put into so tion of a less silicious silicate on any object sub lution directly but the advantages which are fea-, ject to attack of alkalis will be greater than that tures of this invention would not be developed. of a silicate with a higher proportion of silica -T O Heating speeds the rearrangement. The most when the NazO concentrations are'the same. The differences in degree of this action are frequently desirable combination of properties is to be ex It is in many instances necessary never pected ordinarily in freshly prepared solutions. great. theless to use detergents dependent upon power Old solutions cannot be expected to be as effec ful alkaline action in cleaning or other operations 75 tive either in action or protection, even though eyen at the risk of some weakening of flber, etch unused. ' 2,044,467 ‘ ing or other attack. It is to such operations that _ the present invention is particularly directed in that it provides a means of obtaining the highly e?ective detergent or other action of the less sili cious alkali metal silicates with the protective action of those containing relatively more silica. Such a combination of properties is inherent in mixtures such as described. This is due to the 10 15 fact that although such mixtures possess ratios intermediate between the ratios of the constituent 3 2. A detergent composition of matter compris ing a physical mixture of a crystalline hydrated sodium silicate and a second sodium silicate which disperses in water to form a colloidal silicious sys tem, the relative proportions of said silicates being . such as to yield in aqueousrsolution 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 compris- l0 silicates, structural equilibrium between the two ‘ to give the properties of a single silicate of they ing av physical mixture of a crystalline hydrate of sodium metasilicate and a second sodium sili said intermediate composition when put into solu tion is only slowly attained, each constituent sili cate which disperses in water to form a colloidal cate 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 20 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 ac 25 tion; the more alkaline silicate too strong and likely to ruin the ?nish. ,In the mixture the re straining action exerted permits the use of higher temperatures and correspondingly reduced pe-' riods under treatment, or in other cases permits 30 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-" 35 ture of sodium metasilicate pentahydrate and a silicious system, the relative proportions of said silicates‘ being such as to yield in aqueous solution 15 a detergent bath partaking of the individual char acteristics of the said silicates and adapted to be used before equilibrium is attained. 4. A detergent composition of matter compris ing 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 par taking 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 second sodium silicate which it treated separately 3" with water disperses to form a colloidal silicious " composition of claim 4. system. momma: x. cmvnmn'n.