US2724699A - Solid compositions containing polyoxyethylene thioethers and urea - Google Patents

Description

United States Patent SOLID COMPOSITIONS CONTAINING POLYOXY- CETHYLENE THIOETHERS AND UREA George E. Barker, New Castle Hundred, Pleasant Hills, DeL, assignor to Atlas Powder Company, Wilmington,

Del., a corporation of Delaware 5 N0 Drawing. Application July 3, 1951, i

Serial No. 235,089

13 Claims. (Cl. 252-137) This invention relates to solid compositions containing polyoxyethylene thioethers and more particularly to solid compositions containing surface active polyoxyethylene thioethers.

An object of the invention is to provide a solid composition containing a polyoxyethylene thioether.

Another object is to provide a solid composition containing a normally liquid to soft waxy polyoxyethylene thioether. i i

A further object is to provide a solid detergent composition containing a normally liquid to soft Waxy surface active polyoxyethylene thioether. i

The above and other objects will become more fully apparent in the course of the following description.

The polyoxyethylene ethers of certain aliphatic thiols constitute a useful class of surface active agents. They find application as non-ionic emulsifiers, detergents, dispersing and wetting agents. A number of the more useful ethers in this class are liquids or are softwaxy solids at ordinary temperatures. .It is more convenient for some uses of such compounds to have them in solid form, for example, in molded bars or pellets, chips or powder. The conventionalmethod of solidifying fluid detergents is to absorb them into a solid powder or crystalline mass which in some cases may be formed at very high pressures into tablets or bars, but more often than not, such masses are utilized in granular form. The number of suitable absorbent materials is limited and their presence in the end'product is often undesirable, especially in the large proportion necessary todry up the oily detergent.

In accordance with the present invention I solidify surface active polyoxyethylene thioethers by admixture with urea. The reaction responsible for the solidification is not clearly understood but it is definitely different from the mere absorption of liquid by a solid. The bee havionis more like the setting of cement or concrete in that a pasty mixture of finelypowdered urea and liquid polyoxyethylene thioether may remain apparently unchanged duringan incubation periodof varying length depending upon the particular thioether, the particle size of the urea, and the proportionof ingredients, after which amore or less rapid solidification of the entire mass takes place. Other. ingredients may be incorporated in the mixture to be solidified for the tying the final product. For example, detergent aidsor buildraauxiliary emulsifying agents, ormaterials calculated to reduce the rateof solution of the solidified mixture in water may be added without inhibiting the concretion reactionand without departing fromthe, spirit of my invention. i

Thioethers which I may employ in practicing my invention are polyoxyethylene derivatives of aliphatic thiols containing at least 12 but not more than 20 carbon atoms and containing only carbon and hydrogen besides the sulphur of the thiol group. Further, they contain a chain comprising a plurality of oxyethylene groups, the chainterminating in hydroxyl. The compounds so described may be represented by the formula;

. RS(CH2CH2Q)11H- in which R'is an unsubstituted alkyl radical containing from 12 to 20 carbon atoms and n is a number equal equal to at least two-thirds of the number of carbon atoms in R.

purpose of suitab1y-modi-.

Typical thioethers falling within the generic group so represented are the polyoxyethylene ether of tertiary dodecyl mercaptan in which the average number of oxyethylene groups is 8, the polyoxyethylene ether of tertiary dodecyl mercaptan in which the average number of oxyethylene groups is 12, the polyoxyethylene ether of tertiary dodecyl mercaptan in which the average number of oxyethylene groups is 30, the polyoxyethylene ether of n-hexadecyl mercaptan in which the number of oxyethylene groups is 20, and the polyoxyethylene ether of eicosyl mercaptan in which the number of oxyethylene groups is 25. The number of oxyethylene groups in the thioethers of my invention is equal to at least two-thirds of the number of carbon atoms in the thiol portion of the ether. The upper limit of the number of oxyethylene groups which may be present is the practical one of the effect of excessive oxyethylation on the physical properties of the thioether. It is well known in the art that when the polyoxyethylene chain is long the derivative containing such chain becomes harder with increasing oxyethylation. The practical need for setting up a concreted. mix with urea becomes of less importance with such compounds. The number of oxyethylene groups beyond which hardening with urea is unnecessary obviously varies among the thiols which may be etherified and varies also with the requirements of the use to which the derivatives are to be put.

Polyoxyethylene thioethers useful in compounds of my invention may conveniently be made by the direct addition of. the desired amount of ethylene oxide to thiols according to well-known methods, in which case the resulting ether is not a chemically homogeneous product but comprises a mixture of polyoxyethylene thioethers among which the number of oxyethylene groups varies about the number n which is the average number of polyoxyethylene groups per mol of thiol residue in the 7, product. Similarly, the thiol from which a polyoxyethylene ether useful in my invention is prepared need not be a single chemical entity but may be a mixture of thiols such, for example, as might be derived by the reaction between hydrogen sulfide and polymerized isomerized lower olefines. The nominal hydrocarbon chain length is, then, the average number of carbon atoms in the alkyl radical of the resulting mercaptan.

solidified compositions comprising urea and the above described thioethers may be prepared in a number of methods within the scope of my invention. Generically, the several methods comprise the steps of preparing an intimate mixture of urea and the normally liquid to soft waxy polyoxyethylene thioether under conditions such that the said ether is in a fluid state, and allowing the mixture to set up to a solid form. Specifically, the methods vary in the means by which the intimate mixture is formed. Most simply, this may be accomplished by mixing finely divided solid urea with the polyoxyethylene thioether at a temperature suflficiently high to render the latter ingredient fluid, but well below the melting point of urea; the resultant pasty mass is then formed into the desired shape, and held in a mold until concretion occurs. More rapid concretion may sometimes be obtained by passing the mixture of urea and polyoxyethylenethioethcr through a soap mill to obtain very intimate 3 point of urea, and allow the mixture to cool and undergo concretion. Because of the very intimate mixture obtained by mixing the ingredients in the molten condition, concretion between the crystallizing urea and the thioether is very rapid; frequently being complete by the time the composition has cooled to room temperature. In operating by this method the molten mixture may be poured in molds to form bars or cakes, or the molten mixture may be sheeted on chilled surfaces to form flakes, or may be allowed to set into hardened massive pieces for later grinding or chipping to form flakes, granules or powder as desired. Heating the mixture to temperatures much above the melting point of urea should be avoided to minimize thermal decomposition thereof.

A third method of producing concreted compositions of urea and polyoxyethylene thioethers is to prepare an aqueous mixture of the components, containing up to 50% water, subject the mixture to spray drying treatment according to techniques well known in the art, and allow the concretion process to occur in the granules so formed. The very intimate contact between the growing crystals of urea and the said ether which is established in the spray droplets as the water evaporates is conducive to rapid concretion. This third described method is especially useful for preparing the compositions of the invention in granular form.

The proportion of urea to surface active polyoxyethylene thioether in the compositions of my invention may be varied between Wide limits. When there is no other component in the mixture I generally prefer to use at least 30 parts of urea to 70 parts of the polyoxyethylene thioether. Hard, dry, products are obtained at all higher ratios although I prefer not to exceed a ratio of 90 parts urea to 10 parts of the said thioether.

In the presence of solid additives such as alkaline detergent builders', sodium sulfate, clay, and the like, I frequently find it possible to use smaller proportions of urea to polyoxyethylene thioether than is indicated above. A common disadvantage of granular detergent compositions comprising liquid surface active agents absorbed in alkaline detergent builders is that, on storage, the liquid tends to bleed from the mixture, especially if it is in contact with an absorptive substance such as chip board or card board containers. A real problem in economical packaging is thus raised. The present invention offers a convenient solution to this problem. By employing as the liquid surface active agent a polyoxyethylene thioether within the range of compositions cited herei'ribe'fore, and by including in the built detergent composition a suitable proportion of urea, the concretion reaction between the two a serves to bind the excess liquid detergent and prevent bleeding thereof from the mixture. An especially useful embodiment of my invention therefore comprises a granular, alkaline built, detergent containing as its surface active agent the solid concretion products disclosed herein. In such compositions I prefer to employ at least 50% of the said alkaline detergent builder and sufficient of the said concretion product to provide at least 3% of the polyoxyethylene thioether in the form of its concretion product.

Any of the well known alkaline detergent builders can be employed to so prepare non-bleeding built detergents in which the surface active agent is a liquid. Among such may be named trisodium phosphate, tetrasodium pyrophosphate and other polyphosphates, sodium carbonate, sodium sesquicarbonate, sodium metasilicate, boraxand its variously dehydrated derivatives, and the like. The compositions may be prepared by any suitable means,

such, for example, as by mixing the alkaline builder and.

urea, then adding the polyoxyethylene thioether and thoroughly incorporating it, and allowing the mixture to stand until all free liquid has set to a solid with the urea, or by preforming the solidified urea-polyoxyethylene thioether product by any of the methods described hereinbefore,

converting it to granular form and mixing it with the granular alkaline builder.

The following nonlimiting examples of compositions made according to my invention are illustrative of its practice.

Example I Thirty-five grams of the polyoxyethylene thioether of tertiary dodecyl mercaptan averaging 12 oxyethylene groups per mol was intimately mixed with 65 grams of crystalline urea. The mixture was formed into a compact mass and allowed to stand at room temperature. After 24 hours the mixture had set to a hard mass which could be ground to a dry powder.

Example 2 Fifty grams of the polyoxyethylene thioether of tertiary hexadecyl mercaptan averaging 16 oxyethylene groups per mol was intimately mixed with 50 grams of finely powdered solid urea'at 50 C. The mixture was formed into a compact mass and allowed to stand at room tempera! ture. After 1 hour the mixture had set to a hard mass which could be ground to a dry powder.

Example 5 Seventy grams of a water soluble polyoxyethylene thioether of dodecyl mercaptan containing apparently morethan 8 oxyethylene groups per mol, and commercially available under the designation Nyon 218, was intimately mixed with 30 grams of finely powdered solid urea at 30 C. The mixture was stirred, poured into a mold and allowed to stand at room temperature. After 24 hours the mixture had set to a firm, solid mass. 5

Example 6 This example illustrates the second method of the invention. Ninety grams of urea was melted by heating on an oil bath (165 C.). Ten grams of the polyoxyethylene thioether of dodecyl mercaptan averaging 10 oxyethylene groups per mol was added to the molten urea, the mixture was stirred, and poured into a mold. On cooling, the melt hardened to a solid, which could be ground to a dry powder.

Example 7 To prepare a composition of my invention in a spra tower, a mixture of 65 parts of urea and 5 parts of Water is heated to C.-l20 C. 35 parts of the poly oxyethylene thioether of dodecyl mercaptan containing an average. of 12 oxyethylene groups per molecule is added, maintaining the temperature at 115 C. C. The mixture is atomized by means of a spray nozzle into the top of a tower about 30' feet high with an incoming countercurrent flow of cold air. The product collected at the bottom of the tower is moved to storage until set.

Example 8 I A second set of conditions for operating a spray tower for preparing compositions of my invention follow: A mixture of 65 partsv of urea and 25 parts of water is heated to 100 C. 35 parts of the polyoxyethylene thioether of dodecyl mercaptan containing an average of 12 oxyethylene groupsfl-per molecule is added, maintaining the temperature at 100 C. The mixture is atomized by means of. a spray nozzle into the top of a tower about 30 feet high with an incoming co-current flow of hot air (350400 F.), which leaves the tower at 100150 F.

r the thioether.

Example 9 In order to prepare a composition containing a detergent builder by the method of my invention, twenty grams of urea was mixed with 100 grams of tetrasodium pyrophosphate. To this dry mixture was added 80 grams of the polyoxyethylene thioether used in Example 5 and the whole was mixed thoroughly to give a rather fluid slurry. After 48 hours the mixture had set to a solid mass which could be chipped to yield flakes which were superficially dry. A similar composition in which the urea was replaced by additional tetrasodium pyrophosphate remained as a fluid slurry indefinitely.

The tetrasodium pyrophosphate of the foregoing example may be replaced by trisodium phosphate, sodium tetraborate pentahydrate, sodium sesquicarbonate, or the like, to yield granular, alkaline built detergents of varying alkalinity.

. Example 10 Equal parts by weight of granular sodium metasilicate and the granular product of Example 7 are thoroughly commingled in a ribbon mixer to yield an all-purpose, granular alkaline-built detergent.

The foregoing description and illustrative examples are indicative of the broad scope of my invention. Within this broad scope I prefer to use as the nonionic surface active agents polyoxyethylene thioethers of tertiary dodecyl mercaptan containing averages of from 8 to 12 oxyethylene groups per mol of thiol. As has already been indicated, preferred ratios of ureato polyoxyethylene thioether may vary according to the type of product desired and with the physical character of When employing the preferred polyoxyethylene ethers of tertiary dodecyl mercaptan containing averages of from 8 to 12 oxyethylene groups per mol and in the absence of additives other than urea I find that excellent compositions for pressing into bars may be obtained by combining from 30% to 70% of the said thioether with from 70% to 30% of urea.

This application is a continuation in part of my application Serial Number 69,984, filed January 8, 1949, now abandoned.

I claim:

1. A composition consisting essentially of the solid concretion product of urea and a normally liquid to soft waxy polyoxyethylene thioether of the formula:

soft waxy polyoxyethylene thioether of the formula:

RS (CHzCHzO) nH in which R is an unsubstituted alkyl radical containing from 12 to carbon atoms and n has a value equal to at least two-thirds the number of carbon atoms in R,

. wherein the ratio of urea to said thioether lies between the inclusive limits of 30/ 70 and 90/ 10.

4. A composition as in claim 3 in which R is a tertiary dodecyl radical and n is at least 8.

5. A granular, alkaline-built, detergent composition comprising at least 50% of an alkaline detergent builder selected from the group consisting of phosphates, silicates, borates and carbonates of sodium and suflicient of the product of claim 1 to provide at least 3%, based on the total composition, of the said polyoxyethylene thioether in the form of its concretion product with urea.

6. The method which comprises intimately admixing urea and a normally liquid to soft waxy polyoxyethylene thioether of the formula:

RS CH2CH2O all in which R is an unsubstituted alkyl radical containing from 12 to 20 carbon atomsand n has a value equal to at least two-thirds the number of carbon atoms in R, the said polyoxyethylene thioether being: in a liquid state; the quantity of urea so admixed being sufiicient to combine with said thioether to form a concreted mixture; and allowing the mixture to set up to a solid form.

7. The method defined in claim 6 wherein the ratio of said urea to said polyoxyethylene thioether lies between the inclusive limits of 30/ 70 and. /10.

8. The method which comprises intimately admixing finely divided solid urea and a normally liquid to soft waxy polyoxyethylene thioether of the formula:

RS (CHzCHzO nH in which R is an unsubstituted alkyl radical containing from 12 to 20 carbon atoms and n has a value equal to at least two-thirds the number of carbon atoms in R, the said polyoxyethylene thioether being in a liquid state; the quantity of urea so admixed being sufficient to combine with said thioether to form a concreted mixture; and allowing the mixture to set up to a solid form.

9. The method defined in claim 8 wherein the ratio of the said urea to said polyoxyethylene thioether lies between the inclusive limits of 30/ 70 and 90/ 10.

10. The method which comprises intimately admixing molten urea and a normally liquid to soft waxy polyoxyethylene thioether of the formula:

RS (CHzCHzO nH in which R is an unsubstituted alkyl radical containing from 12 to 20 carbon atoms and n has a value equal to at least two-thirds the number of carbon atoms in R, the quantity of urea so admixed being sufficient to combine with said thioether to form a concreted mixture; allowing the mixture to cool, and to set up to solid form.

11. The method as defined in claim 10 wherein the ratio of the said urea to said polyoxyethylene thioether lies between the inclusive limits of 30/70 and 90/10.

12. The method which comprises admixing urea and a normally liquid to soft waxy polyoxyethylene thioether of the formula:

RS(CH2CH20)11.H

in which R is an unsubstituted alkyl radical containing from12 to 20 carbon atoms and n has a value equal to at least two-thirds the number of carbon atoms in R, with water to form a sprayable mixture, the quantity of urea so admixed being sufficient to combine with the said polyoxyethylene thioether to form a solid concretion product; spray drying the mixture; and allowing the granules so produced to set up to solid form.

13. The method defined in claim 12 wherein the ratio of the said urea to the said polyoxyethylene thioether lies between the inclusive limits of 30/70 and 90/10.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. A COMPOSITION CONSISTING ESSENTIALLY OF THE SOLID CONCRETION PRODUCT OF UREA AND A NORMALLY LIQUID TO SOFT WAXY POLYOXYETHYLENE THIOETHER OF THE FORMULA: