US2356903A - Soap-free detergents in bar form - Google Patents

Description

Patented Aug. 29, 1944 soar-mas DETERGENTS IN BAR. FORM Richard C. Wood, Cincinnati, Ohio, assignor to The Procter a Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing.

6 Claims.

This invention relates to soap-free detergents in bar form for toilet and bath use. More particularly my invention relates to a method of improving such detergent bars by reducing their tendency to become undesirably soft and smeary when left in a wet receptacle such as an undrained soap dish.

Until recently the only detergents commonly used in bar form for toilet and bath have been soaps of various kinds, such as milled toilet soap and floating bath soap. Several years ago soapfree detergents for general household use and for shampoos and other special purposes came into use, these being in the form of powders, pastes, or liquids. More recently soap-free detergents in bar form for ordinary toilet and bath use have been described. These possess not only most of the desirable properties of toilet soaps but also other advantageous characteristics, especially when used in hard water. The manufacture of wholly satisfactory soap-free detergents in bar form presents many new problems which are not solved by applying experience gained in soap making, because these newer detergents differ greatly from soap in many of their physical and chemical characteristcis.

Soap-free detergent agents (that is, the active detergent ingredients of the soap-free bars) that are especially useful for the above mentioned purposes are those produced from water-soluble salts of sulfated or sulfonated compounds of types which will subsequently be described. When made in bar form for toilet and bath use, these detergent agents are usually mixed and blended with other substances which modify the physical characteristics of the mass and better adapt these agents to the particular purpose for which they are intended.

One type of such modifying agent, which is described in Robert A. Duncans Patent No. 2,175,285, dated October 10, 1939, and which comprises polyhydric alcohols partially esterified with saturated fatty acid having at least twelve carbon atoms in the molecule, possesses the properties of binding together the particles of the detergent agent to form a compact, cohesive bar having a smooth, pleasant feel, and of controlling the exceedingly high solution rate of the detergent agent without interfering with its satisfactory sudsing and detergent action. Somewhat similar properties are possessed by polyhydric alcohols partially esterified with unsaturated fatty acids. modifying agent consists of hydrocarbons derived from petroleum, such as paraflln wax and Application February 5, 1941, Serial No. 377,539

.Another type of oleaginous petroleum Jelly, which when employed in small amounts impart desirable plasticity tothe product, and are helpful in permitting the detergent composition to be milled to a uniform condition, plodded and extruded in continuous bar form, and stamped or pressed into individual bars. A type of modifying agent which has the property of increasing the detergent property of the prodcut comprises higher alcohols having eight or more carbon atoms in a molecule, as more specifically described in W. S. Martins Patent 2 166,- 315, dated July 18, 1939. Water in small amounts may be considered as a non-oleaginous modifying agent, its functions including the prevention of brittleness and the control of softness of the product both during and after its manufacture.

Many soap-free detergent bars of the type herein described, consisting essentially of soluble salts of sulfated or sulfonated compounds blended with suitable oleaginous modifying agents, have been found to have an undesirable tendency to soften in use and to become slimy or smeary especially on the lower surface of the bar when left on a wet washstand or in an undrained soap dish. The presence of partilly esterified polyhydric alcohol modifying agents in the bar does much to reduce this tendency, but it is not always practical to employ a sufficiently high proportion of such a modifying agent, or to employ a modifying agent of this type having sumcient ability to check this tendency satisfactorily. My invention has for its object the overcoming of this tendency of the bars to become undesirably slimy by the employment of means not hitherto employed.

I have found that such soap-free detergent bars which are generally satisfactory except for their tendency to become soft and slimy and waste away too rapidly, are greatly improved in respect to this tendency, and are not impaired with respect to their better qualities, by the incorporation of a substantial amount of finely divided common salt (sodium chloride). I have used amounts of salt ranging from five per cent to forty per cent of the total weight of the bar, depending upon the composition of the remainder of the mixture, with good results. Potassium chloridemay be used instead of sodium chloride to produce a similar effect. I have tried other soluble powdered solids with entirely unsatisfactory results: Powdered sodium sulfate, for example, has been found to increase the tendency of the bar to become smeary on the washstand whereas this tendency is decreased by the employment of sodium chloride or potassium chloride.

The employment of salt (NaCl or KCl) in the formula has other advantages. It produces a mixture of ingredients which may readily be mixed, homogenized, and pressed into bar form by means of equipment commonly used in making milled toilet soap, this equipment comprising a mechanical mixer or amalgamator, one or more sets of milling rolls or mills," a soap plodder, and the usual bar cutting, and stamping or pressing equipment. The use of salt in the formula controls the solution rate of the bar, and hence the release of the active detergent agent, without impairing free lathenng or good detergent action. It permits using as modifying agents polyhydric alcohols partially esteriiied with unsaturated fatty acids without producing an unduly soft bar. It permits using higher proportions of modifying agents tending to soften the product, such as petroleum jelly and water, than could otherwise be used, thus permitting greater freedom of choice in arriving at a for mula that will substantially satisfy the diverse requirements of the ideal product.

The sulfonated or sulfated detergent agents that are especially useful in making my product are the substantially solid water-solubl salts of any of the organic sulfonic or sulfuric acids included in the following group, or any mixture of same, the alkyl radicals in all cases having more than eight carbon atoms: sulfuric reaction products of aliphatic alcohols, of aliphatic hydrocarbons, of alkyl aromatic hydrocarbons and their derivatives, of monoglycerides of higher fatty acids, of high molecular esters of low molecular carboxylic acids, of monoalkyl glyceryl ethers, of high molecular alkyl esters of glycol, and of higher fatty acid amides of lower molecular alkylol amines. Of course there are water-soluble salts of other sulfuric reaction products of high molecular weight organic compounds which are characterized by their high solubility in water, their resistance to precipitation by the constituents of hard water, and their effective detergent prop erties. All of these products fall within the scope of my invention. In the specification and claims reference to sulfuric reaction products and "sulfonated or sulfated products does not necessarily mean that the product is prepared with the use of sulfuric acid or other sulfonating or sulfating agents. I use this terminology to designate broadly those compounds which contain an SOaH group with the sulfur atom attached to a carbon atom either directly or through an oxygen atom linkage.

Those sulfonated and sulfated compounds which I prefer to use are the water-soluble salts of the sulfated alcohols obtainable from the natural fats and fatty oils, oils of the coconut oil type characterized by their high saponification number being of especial value.

As commercially prepared these sulfonated or sulfated detergent agents normally are in powder form containing some impurities, including sodium sulfate and (when chlorsulfonic acid is used in their preparation) some traces of sodium chloride. The amount of sodium chloride present in these detergent agents from this source is not a sufllcient amount to accomplish my object, but it should be considered when calculating the amount of salt required in making my product. The sodium sulfate content of the detergent agent used in making my product should be relatively The salt, preferably sodium chloride, which I use in making my product is usually first reduced to a finelypulverized condition. Powdered salt is not only more effective than ordinary crystalline salt of the degree of fineness characteristic of table salt, but it also makes a smoother and hence more desirable detergent bar. Salt which has been so finely divided that it will pass through a standard 200 mesh screen, having openings of 0.0029 inch, is suitable.

The following examples will illustrate the nature of my invention. Its scope is not limited to the ingredients named in these examples, since it is apparent that in place of any of the ingredients named (other than sodium or potassium chloride, and water) any of many equivalents may be substituted. Likewise its scope is not limited. to the proportions shown in these examples, since the proportions may be varied not only to modify the firmness, solution rate, and .other characteristics of the product, but also to adjust for variations in properties of substituted equivalent ingredients. Thus I have successfully employed proportions of sodium chloride varying from 5 per cent to 40 per cent of the total mixture; proportions of detergent agents (sulfated or sulfonated organic compound) from per cent to 70 per cent; partially esterified polyhydric alcohols from 2 per cent to 33 per cent; hydrocarbon modifying agents from 0 per cent to 30 per cent (although the total of hydrocarbons plus partially esterlfied alcohols has 4 not exceeded 33 per cent) water from 0 per cent to 12 per cent; and even these limits were not necessarily critical. The gist of my invention is the discovery that finely divided sodium and potassium chlorides have the property of reducing the tendency of soap-free detergent bars of the character herein described to become slimy in use, and the proportions of these salts used in such bars are limited only by the desired properties of the product and by the nature and proportions of its other ingredients.

Throughout this specification proportions and percentages denote parts by weight.

Example 1.5 parts of petroleum jelly and 10 parts of a mixture of monoand diglycerides (the latter mixture prepared by heating a quantity of refined and bleached cottonseed oil hydrogenated to an iodine value of 33 with about one fifth its weight of glycerin according to a well known procedure), are melted and mixed together, and into these are added and mixed '70 parts of commercial alkyl sulfate powder (composed principally of sodium salts of sulfated alcohols derived from coconut oil, and containing about 1% sodium chloride), 12 parts of pulverized sodium chloride, and 3 parts of water. The mixture is milled in a well known manner, (except that I prefer to mill the material at temperatures about 5 F. to 10 F. lower than the temperatures normally employed in making milled toilet soap), and pressed into a bar or cake of suitable size and shape.

Example 2.10 parts of petroleum jelly and 10 parts of a mixture of polystearin (polyglycerol incompletely esterified with commercial stearic acid, the molar ratio of glycerol radicals to fatty acid radicals being about 1.0 to 1.5) are melted and mixed together, and into these are added and mixed 35 parts of commercial alkyl sulfate powder derived from coconut oil, 40 parts of pulverized common salt, and 5 parts of water. The mixture is milled as in Example 1 and pressed low, preferably not exceeding about ten per cent. into a bar of suitable size and shape.

Example 3.-Detergent bars were formed by employing the general procedure of Example 1, using the following ingredients:

Parts Allryl sulfate powder, derived from coconut Alkyl sulfat powder, derived from ocenol (crude oleyl alcohol from sperm oil) 3.5 Petroleum jelly l Polystearin l5 Pulverized common salt 30 Water 5 A somewhat firmer product was produced by substituting paraffin wax for a portion of the petroleum Jelly in the above formula.

Example 4.Detergent bars were formed by employing the general procedure of Example 1, using the following ingredients:

Parts Alkyl sulfate powder, derived from coconut oil, containing about 3 per cent of unsui- Having thus described my invention, what I- claim and desire to secure by Letters Patent is:

1. A substantially soap-free detergent in bar form comprising: a substantially solid watersoluble salt of a sulfated fatty alcohol having more than eight carbon atoms in the allwl radical, which salt is characterized by its high solubility in water, its resistance to precipitation by the constituents of hard water, and its effective detergent pr perties; a polyhydric alcohol partiallyesteriiled with a fatty acid having at least twelve carbon atoms in the molecule, in amount not exceeding about thirty-three per cent; and at least about 5 per cent and not over about forty per cent of an inorganic chloride selected from the group consisting of sodium chloride and potassium chloride.

2. A mbltantially soap-free detergent in bar form comprising: a water-soluble salt of an alkyl sulfate having more than eight carbon atoms in the alkyl radical, a polyhydric alcohol partially esteriiled with an unsaturated fatty acid having at least twelve carbon atom in the molecule, in amount not exceeding about thirty-three per cent; and at least five per cent and not over about forty per cent of sodium chloride. h,

3. A substantially soap-free detergent in bar form comprising: about thirty-five to seventy per cent of sodium alkyl sulfates derived from higher alcohols derived from an oil of the coconut oil type; about two to thirty-three per cent of polyhydric alcohol partially esteriiied with an unsaturated fatty acid having at least twelve carbon atoms in the molecule; and about five to forty per cent of sodium chloride.

4. The product of claim 1, in which the inorganic chloride is composed substantially 01' particles sumciently small to p ss through a standard 200 mesh screen.

5. A substantially soap-free detergent in bar form comprising: a water-soluble salt of an alkyl sulfate having more than eight carbon atoms in the alkyl radical; a polyhydric alcohol partially esteriiied with a fatty acid having at least twelve carbon atoms in the molecule, in amount not exceeding about thirty-three per cent; at least five per cent and not over forty per cent of sodium chloride; and petroleum jelly, in amount not exceeding thirty per cent and such that the total of partially esterifled poly ydric alcohol and petroleum Jelly does not exceed about thirty-three percent.

6. A substantially soap-free detergent in bar form comprising: a water-soluble salt of an alkyl sulfate having more than eight carbon atoms in the alkyl radical; a polyhydric alcohol partially esteriiled with a fatty acid having at least twelve carbon atoms in the molecule, in amount not exceeding about thirty-three per cent; at least five per cent and not over forty per cent of sodium chloride; and paraflln wax, in amount not exceeding thirty per cent and such that the total or partially esterifled polyhydric alcohol and paraflln wax does not exceed about thirty-three per cent.

' RICHARD C. WOOD.