US3625906A

US3625906A - Soap-detergent tablets

Info

Publication number: US3625906A
Application number: US771613A
Authority: US
Inventors: Allan Alsbury; Dennis Parker Barrett
Original assignee: Lever Brothers Co
Current assignee: Lever Brothers Co
Priority date: 1967-11-16
Filing date: 1968-10-29
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07
Also published as: BR6804035D0; DE1809034B2; ES360296A1; SE355192B; FI48940C; FR1593213A; NO127305B; AT292895B; NL6816268A; LU57336A1; GB1185317A; DE1809034A1; CH511282A; DK132093C; DK132093B; FI48940B; BE723810A; NL157053B

Abstract

Personal washing tablets consisting essentially of a soap and an alkali metal or alkaline earth metal sulfate of a primary alcohol 10-75 percent of the molecules of said alcohol being branched, and wherein the soap content is 90-40 percent by weight of the combined contents of the soap and the sulfate.

Description

United States Patent Inventors Allan Alsbury;

Dennis Parker Barrett, both of Win- England App]. No. 771,613

Filed Oct. 29, 1968 Patented Dec. 7, 1971 Assignee Lever Brothers Company New York, NY.

Priority Nov. 16, 1967 Great Britain 52,254/67 SOAP-DETERGENT TABLETS 7 Claims, No Drawings US. Cl 252/121, 252/132, 252/161, 252/DlG. 16 Int. Cl Clld l/l4, Cl ld 9/32, Cl ld 9/48 Field of Search 252/1 17,

Neodol Surfactants" published by Shell Chemical Company, 1967, page 5.

Primary Examiner-Herbert B. Guynn Assistant Examiner-Dennis L. Albrecht Allorne vL0uis F. Kline, Jr.

ABSTRACT: Personal washing tablets consisting essentially of a soap and an alkali metal or alkaline earth metal sulfate ofa primary alcohol 10-75 percent of the molecules of said alcohol being branched, and wherein the soap content is 90-40 percent by weight of the combined contents of the soap and the sulfate.

SOAP-DETERGENT TABLETS This invention relates to soap tablets which include a synthetic detergent.

Tablets made from soap alone suffer from the disadvantages of inadequate lather produced in personal washing, and in the formation of curdy scum in hard water, i.e. water containing calcium and/or magnesium ions, which leaves an objectionable deposit on handbowls and baths (bathtub ring).

Toilet bars made from synthetic detergents, whilst giving an acceptable volume of lather, generally yield a lather having an open, noncreamy structure, unlike that from soap and not as acceptable generally to the user of the bar for personal washing. The rates of wear in use of synthetic detergent bars tend to be much higher than those of soaps. Many synthetic detergents, however, have the advantage that they do not produce the objectionable scum that is characteristic of soaps.

It is also known that many synthetic detergents are incompatible with soap, in that their lathering actions are mutually destructive.

It has now been found that blends of soaps with the alkalimetal or alkaline earth salts of the sulfates of certain synthetic alcohols are not only compatible, as regards lathering properties, but that the lather volume produced is unexpectedly high. The unexpectedly high lather volumes are now found to accrue from tablets wherein the soap and sulfate are present within critical limits. The quality of the lather, i.e. its closeness and creaminess, is good. In these blends the scum formation characteristic of the soap element is suppressed or eliminated. Furthermore these advantages are achieved whilst maintaining a user-acceptable rate of wear of the bar in use.

The present invention is concerned with a toilet table which comprises a soap and an alkali metal or alkaline earth metal sulfate of a primary alcohol, 10-75 percent of the molecules of said alcohol having the formula wherein n is an integer from 7-14, R is a substituent which is an aliphatic radical having one-four carbon atoms, and the number of carbon atoms totals l [-1 8, in which the soap content is 90-40 percent by weight of the combined contents of the soap and the sulfate.

The sulfate will be referred to hereafter as the branched chain alkyl sulfate." Suitable alkali metals are sodium and potassium, and suitable alkaline earth metals are calcium and magnesium.

The preferred primary alcohols are those branched per 100 molecules of alcohol, to the extent of 50-90 molecules unbranched, 10-50 molecules having R as methyl, -10 molecules having R as ethyl, and 0-15 molecules having R as an alkyl radical of three or four carbon atoms.

Preferably, the branched chain alkyl sulfate is one which is made by sulfation of alcohols having l2-l5 carbon atoms. Preferably the substituent R is methyl, and the cation is preferably sodium.

The unexpectedly high lather volume values accrue from tablets wherein the branched chain alkyl sulfate lies within the range of about 10 to about 60 percent by weight of active detergent material, i.e. soap plus branched chain alkyl sulfate. That is, a 60:40 mixture of sulfatezsoap represents the terminal region at which the unexpectedly high lather volume is obtained. Although with some blends of soap and branched chain alkyl sulfates, where the amount of sulfate is at the lower end of the range of the invention, the rate of wear of the tablets, whilst being user acceptable, is as expected from the composition. Further, when the larger amounts of the branched chain alkyl sulfate within the range of the invention are used, it has surprisingly been found that the rate of wear does not increase further, but in fact is less than expected from the composition of the tablet.

The preferred ratios of soap to branched chain alkyl sulfate lie within the range 5:] to 3:2. When the degree of branching in the branched chain alkyl sulfate is low at the percent level of branching, then the amount of the sulfate required is of the order of 45 percent, and when the branching is higher, at say 40 percent, then the amount of the sulfate needed is of the order of 25 percent. Generally, the preferred amount of branched chain alkyl sulfate is about 30 percent by weight of soap plus the alkyl sulfate.

The preferred sulfates may be made from the alcohols which are commercially known as Dobanols (Shell Chemical Co. RTM) in the UK and Neodols in the USA. These alcohols include both odd and even numbered carbon chains in the range of 12-15 carbon atoms are branched to the extent of 25 percent; it is believed that 25 percent branching is Z-methyl.

The sulfation of these alcohols and the subsequent neutralization may be carried out by methods using a sulfating agent such as SO /air, chlorosulphonic acid etc., for example in a stirred tank, or in a falling film reactor. The product of sulfation is neutralized preferably by aqueous caustic soda. It has been found that the resultant neutralized paste can then be coprocessed with the soap-stock by the normal soap processing techniques of drying, milling, plodding and stamping to yield firm bars of excellent surface finish.

The soap component of the tablets may be selected from a wide range of fat-charges as is familiar in the soapmaker's art. For example it may be derived entirely from tallow, i.e. the natural fat in which the fatty acid distribution is generally understood to be mainly 30 percent C and 20 percent C saturated with 42 percent C unsaturated. In place of tallow, various oils and fats commonly used in soap-making may be used, for example, bone-grease, Chinese vegetable tallow, cottonseed oil, partially hydrogenated groundnut oil, lard, palm oil, or whale oils.

Or it may be a blend derived from tallow with a nut oil, for example palm kernel or coconut oil. Typically, the fatty acid distribution in nut-oils is 45 percent C 14 percent C and 10 percent C saturated and 20 percent C unsaturated. The soap may also contain 10-20 percent of a fatty acid derived from a soft oil i.e. ground-nut oil. The blend of tallow and nut oil soaps may be in the ratios commonly used in toilet soaps, for example in the UK such ratios could be :20, 50:50, 40:60, or 35:65. The higher nut oil concentrations are not commonly used elsewhere. Soaps derived from synthetic fatty acids of similar chain length distribution may be used.

The soap base may, optionally be superfatted, for example by the addition of free fatty acids. This is a common practice in soap toilet bars as a method of achieving an increased creamy fee] which is considered desirable from a consumers viewpoint. The amount of superfatting agent is generally about 10 to 20 percent based on the soap present, but may be up to 30 percent, or even 50 percent based on the soap content, in the tablets of the invention which have the lower soap content. Where the superfatting agent is chosen to be a free fatty acid, this may be liberated in situ by the addition of certain mineral or organic acids e.g. phosphoric acid or lactic acid. However, the fatty acid or other selected superfatting agent may have the same or different carbon chain distribution from that of the soap component.

The invention will now be described by way of examples in which the branched chain alkyl sulfates are derived from the Dobanol (Neodol) alcohols designated 45, 23 and 25, i.e. blends having carbon chain lengths ofC and C C and C and C C, C and C respectively, and are the sodium salts.

In the following examples the figures in brackets represent respectively the expected levels of lather volume, and rate of wear i.e. the volume or rate of wear calculated from a linear relationship drawn between the volumes or rates of wear obtained for a bar whose active consists of percent specified soap and a bar whose active consists of 100 percent specified alkyl sulfate.

The methods used to obtain the results quoted in the examples are detailed later. All percentage compositions are on a dry weight basis.

EXAMPLE 1 Toilet bars were prepared by normal soap processing techniques to the compositions in the following table.

The soap used consisted of the sodium salts of the fatty acids derived from toilet grade tallow.

Percentage composition Lather Rate of wear Mush, volume (machine wt. Total Dobano146, at 20 C. test) at 20 loss mush Soap sulphate (mls.) C. gms. (gms) (gins) Synergistic lather volume is shown by compositions containing 20, 40 and 60 percent of the branched chain alkyl sulfate, whilst negligible changes in rates of wear and mushing tendencies are effected (negligible change is one which is insufficient to be appreciated by a user).

EXAMPLE 2 Toilet tablets containing sodium soap derived from the fatty acids of tallow and palm kernel oil in the ratio of 4:1 and Dobanol 45 sulfate were prepared according to the composition given below.

Percentage composition Lather Rate of wear Mush, volume (machine wt Total Dobanol45, at 20 C. test) at 20 loss mush Soap sulphate (mls.) C. gms. (gms (gms.)

The lather volumes of blends containing 20 and 40 percent Dobanol 45 sulfate are higher than anticipated from their compositions. Although they contain the readily soluble alkyl sulfate, the rates of wear and moshing tendencies are surprisingly little affected.

EXAMPLE 3 Toilet bars were made from soap consisting of the sodium salts of the fatty acids derived from tallow and palm kernel oils in the ratio of 3:2, with 10 percent by weight of fatty acids of the same composition as superfatting agents, and Dobanol 45 sulfate, as shown in the table.

Percentage Composition Lather volume Soap Dobanol 45 C. 40 C.

sulfate Synergistic lather volume production is shown by these examples.

EXAMPLE 4 Toilet bars were prepared, by normal soap processing techniques, to the composition shown in the following table.

The soap used in the example comprises the sodium salts of equal parts of the carboxylic acids derived from tallow and coconut oil, with 10 percent by weight of added free fatty acids of the same composition.

The sodium salt of the sulfate obtained from Dobanol 45 was used.

Ratc-of-wear Percentage composition Lather volume (mls.) (machine test) gins.

Soap sulphate 20 C. 40 C. 20 C. 35 C.

These data show the marked synergism in lather volume by the compositions of the invention.

EXAMPLE 5 The invention is similarly exemplified when the sodium salt of the sulfate derived from Dobanol 23 is used in the same superfatted soap blend as used in example 4.

ll COmPOSlU'OH Lather volume Rate of Wear Soap Dobanol 23 at 20 C (ml (Hand washing sulfate test) at 20 C. gms.

Synergism in lather volume is demonstrated by the composition according to the present invention. This example also shows that when a higher amount of the branched chain alkyl sulfate is used, only the expected lather volume is obtained, and there is a considerable increase in rate of wear over the composition in the preferred range.

EXAMPLE 6 The invention can be further exemplified when Dobanol 25 sulfate is incorporated in toilet bars containing a superfatted soap base consisting of equal parts of the sodium salt of the fatty acids derived from tallow and coconut oil together with 10 percent by weight of the free fatty acids.

Percentage Composition Lather volume Toilet bars containing soaps consisting of the sodium salts of the fatty acids derived from tallow and palm kernel oil in the ratio of 2:3, and 20 percent Dobanol 45 sulfate were made. Similar bars were also made containing 10 and 20 percent by weight of fatty acids of the same composition as superfatting agent.

Percentage Composition Lather volumes at 20 C. Soap alone 369 Soap plus 10% superfat 749 Soap plus 10% superfat plus 20% Dobanol 45 sulfate 394 (748) Soap plus 20% superfat 674 Soap plus 20% superfat plus 20% Dobanol 45 sulfate 836 (688) Soap plus 20% Dobanol 45 sulfate 695 (443) Dobanol sulfate alone 739 These data demonstrate that synergism in lather volume is present when soap/branched chain alkyl sulfate blends are used alone or with 10 and 20 percent fatty acids as superfatting agent.

EXAMPLE 8 Toilet bars have been made containing a :superfatted soap base consisting of the sodium salts of the fatty acids derived from tallow and coconut oils in the ratio of 7:13 together with 10 percent by weight of the free fatty acids, and Dobanol 45 sulfate in the proportions indicated in the table below.

The synergistic lathering action of compositions within the invention is demonstrated, as in the nonadverse effect on the rate of wear and mushing tendencies.

EXAMPLE 9 Toilet bars have been made containing the superfatted soap base as described in example 8 and Dobanol 25 sulfate in the proportions indicated in the table below.

Percentagecompositlon Lather Rateolwear Mush, volume (machine wt Total Dobanol45, at 20 0. test) at 20 loss mush Soap sulphate (m1s.) C. gms. (gms.) (gms.)

The synergistic lathering action of compositions within the invention is demonstrated, as is the nonadverse effect on rate ofwear and mushing tendencies.

it will be appreciated that the tablets of the present invention may include coloring agents, perfumes, germicides, bacteriostats, or agents for improving the characteristics of feel. These agents are well known in the art.

TEST METHODS Lather Volume Test The tablet is conditioned by use in normal washing once or twice to produce an in-use" rather than fresh surface. This ensures that the surface is the same at the beginning as at the end of the test.

The operator uses 2% liters of water at the desired temperature (usually 20 C. or 40 C.) in a hand bowl. Surgical quality rubber gloves are worn to obviate the variable effects of sebum from the skin, without destroying the sensitivity of the operation. The gloved hands and the table are dipped into the water, removed and the tablet twisted 15 times in the hands as in normal washing, then placed on a drained dish. The hands are rubbed together, palm to palm 10 times, then each hand twisted in the other, alternately 10 times. The rubbing and twisting sequence is repeated and the lather so formed collected in a measuring cylinder.

The sequence of operations from the twists of the tablet is repeated twice more and the total volume of lather from the three latherings measured.

Tests are performed, desirably in duplicate.

Rate of Wear-Hand Washing Test A panel of six testers working in rotation washes down each tablet 6 times per day for 4 days. Each wash-down consists of 40 twists, a twist being defined as a rotation of the tablet through 180 in the hands. Two conditions are normally used for the test; tablets are washed-down in water (a) at 20 C. and (b) at 40 C. and kept on drained dishes between wash-downs.

The tablets are then air dried to constant weight (usually for 5 days), and the rate of wear results are given as the dry weight loss in grams."

Tablets of the same size and shape are used, otherwise it is necessary to adjust the weight losses for tablets of difierent surface areas.

Rate of WearMachine Test Bars of test material are subjected to controlled mechanical abrasion under fixed conditions of time, load and intermittent wetting at a chosen, controlled temperature. The weight losses, after drying, are sensibly related to those occurring in normal use.

MUSH

The weighed (W tablets, as rectangular blocks, are suspended in about 100 ml. of water at 20 C. for 2 hours, so that a known surface area (A) is immersed. On removal, the tablet is reweighed (W,,,). The mush is removed with a straight edge (e.g. a polythene scraper), the tablet gently wiped free from mush with a tissue and, after drying in air overnight, reweighed (W,);

I Weight 1oss= per 50 sq. om.

Total mush= fi per 50 sq. cm.

What is claimed is:

l. A toilet table having synergistic lather volume essentially of a. a sodium soap selected from the group consisting of sodium tallow soap and mixtures of sodium tallow soap with sodium palm kernel oil soap or with sodium coconut oil soap in the weight ratio of from :20 to 35:65, and

b. a sodium sulfate salt of mixed C to C linear primary alkanols, about 25 percent of which molecules have a 2- methyl branch chain; the weight ratio ofsoap to sulfate being from 80:20 to 40:60.

2. The toilet tablet as defined by claim 1 which further contains about lO-20 percent by weight of the soap of a free fatty acid superfatting agent derived from said soap.

3. The toilet as defined by claim 1 wherein component (a) is sodium tallow soap, and component (b) is the sodium sulfate salt of mixed C to C linear primary alkanols, about 25 percent of which molecules have a 2-methyl branch chain; the weight ratio of soap to sulfate being about 40:60.

4. The toilet tablet as defined by claim 1 wherein component (a) is a mixture of sodium tallow soap with sodium palm kernel oil soap in the weight ratio of about 80:20, and component (b) is the sodium sulfate salt of mixed C, to C linear primary alkanols, about 25 percent of which molecules have a 2-methyl branch chain; the weight ratio of soap to sulfate being about 60:40.

5. The toilet table as defined by claim 2 wherein component (a) is a mixture ofsodium tallow soap with sodium coconut oil soap in the weight ratio of about 35:65, and component (b) is the sodium sulfate salt of mixed C to C linear primary alkanols, about 25 percent of which molecules have a 2-methyl branch chain; the weight ratio of soap to sulfate being about 70:30; said toilet tablet further containing about 10 percent by weight of the soap of a free fatty acid superfatting agent derived from said soap.

6. The toilet tablet as defined by claim 5 wherein the weight ratio of soap to sulfate is about 60:40.

consisting 7. The toilet tablet as defined by claim wherein the weight ratio of soap to sulfate is about 50:50.

Claims

2. The toilet tablet as defined by claim 1 which further contains about 10-20 percent by weight of the soap of a free fatty acid superfatting agent derived from said soap.
3. The toilet as defined by claim 1 wherein component (a) is sodium tallow soap, and component (b) is the sodium sulfate salt of mixed C14 to C15 linear primary alkanols, about 25 percent of which molecules have a 2-methyl branch chain; the weight ratio of soap to sulfate being about 40:60.
4. The toilet tablet as defined by claim 1 wherein component (a) is a mixture of sodium tallow soap with sodium palm kernel oil soap in the weight ratio of about 80:20, and component (b) is the sodium sulfate salt of mixed C14 to C15 linear primary alkanols, about 25 percent of which molecules have a 2-methyl branch chain; the weight ratio of soap to sulfate being about 60:40.
5. The toilet table as defined by claim 2 wherein component (a) is a mixture of sodium tallow soap with sodium coconut oil soap in the weight ratio of about 35:65, and component (b) is the sodium sulfate salt of mixed C14 to C15 linear primary alkanols, about 25 percent of which molecules have a 2-methyl branch chain; the weight ratio of soap to sulfate being about 70:30; said toilet tablet further containing about 10 percent by weight of the soap of a free fatty acid superfatting agent derived from said soap.
6. The toilet tablet as defined by claim 5 wherein the weight ratio of soap to sulfate is about 60:40.
7. The toilet tablet as defined by claim 5 wherein the weight ratio of soap to sulfate is about 50:50.