US3494869A

US3494869A - Superfatted soap bars and process for their preparation

Info

Publication number: US3494869A
Application number: US564027A
Authority: US
Inventors: Joseph Armstrong
Original assignee: Lever Brothers Co
Current assignee: Lever Brothers Co
Priority date: 1966-07-11
Filing date: 1966-07-11
Publication date: 1970-02-10
Anticipated expiration: 1987-02-10
Also published as: DE1617225A1; ES342853A1; CH489599A; GB1188006A; BE701148A; LU54080A1; GR33186B; NL6709575A; SE329228B

Description

United States Patent 3,494,869 SUPERFATTED SOAP BARS .AND PROCESS FOR THEIR PREPARATION Joseph Armstrong, Norwood, N2J., assignor to Lever lli'others Company, New York, N.Y., a corporation of awe No Drawing. Filed July 11, 1966, Ser. No. 564,027

Int. Cl. Clld 9/34, 9/14 U.S. Cl. 252-109 6 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to soap compositions and a process for their preparation and more particularly to superfatted soap bars and a process for their preparation.

Soap bars having a high content of coconut oil soap are highly advantageous in that they produce voluminous lather. However, such soap bars suffer from the fact that they are almost always sandy and irritating to the skin.

Therefore, it is an object of the present invention to prepare soap bars having a high content of coconut oil soap, but which are neither sandy nor irritating to the skin.

It is a further object of the present invention to provide high content coconut oil soap bars which produce copious lather and which bars are firm and stable against discoloration and odor.

Another object of the present invention is to provide high content coconut oil soap bars which can be pro duced at a low cost and can be made from a composition having excellent extrudability.

The process of the present invention for the preparation of high lathering, firm, stable, non-sandy, non-irritating, superfatted soap bars comprises preparing and mixing in suitable equipment, such as a mixer or a crutcher, an aqueous blend containing a number of essential components discussed below.

An essential component of the aqueous blend is from about 25% to about 55% by weight of a mixture in the relative amounts of from about 10% to about 30% by weight of potassium coconut oil'soap and from about 90% to about 70% by weight respectively of sodium coconut oil soap. The aqueous blend further contains from about to about 30% by weight of sodium tallow soap. Another essential component of the aqueous blend is from about 2% to about 8% by weight of an acidulating agent. Of course, water constitutes the remaining essential component of the aqueous blend and is present therein in an amount from about 28% to about 45 by Weight.

The acidulating agent is a phosphorus-containing inorganicacidic compound having a pH below 7, i.e., inorganic phosphorus acids and their strong acid salts, such as orthophosphoric acid (H PO monosodium dihydrogen orthophosphate (NaH PO pyrophosphoric acid (H P O disodium dihydrogen pyrophosphate (Na H P otrimetaphosphoric acid (11 F 0 tetrametaphosphorie acid (H P O triphosphoric acid (H P O and tetraphosphoric acid (H P O The 3,494,869 Patented Feb. 10, 1970 acidulating agent reacts with the coconut oil and tallow soaps to form the free fatty acids thereof in situ in view of the fact that the acidulating agent has a stronger acidity than the fatty acids in the soaps. However, very strong acidulating agents, such as mineral acids, for example hydrochloric acid, cannot be used to form the free fatty acid superfatting agent in view of the fact that such acids are corrosive and incompatible with the other components of the soap bar in that they impart a deleterious odor and/or color thereto, and their salt by-products frequently have solubilities or other properties, such as efliorescence, which are undesirable. Moreover, the free fatty acid superfatting agent must be formed in situ by the interaction of the acidulating agent with the coconut oil and tallow soaps rather than by the direct blending of free fatty acids into the aqueous blend, because the direct blending of free fatty acids, such as stearic acid or myristic acid, into the aqueous blend is costly and produces superfatted coconut oil soap bars which suffer from discoloration and poor odor on storage and inadequate latherability.

After the aqueous blend discussed above has been prepared and the components thereof mixed together, it is then dried to a moisture content of from about 5% to about 12% by weight. Thereafter, the dried blend is formed into soap bars by conventional methods.

Turning now to a consideration of .the soap bars of the invention, they are supenfatted in view of the free fatty acid content therein which is for-med in situ by the above process. Moreover, the soap bars have the highly desirable properties of being high lathering, stable against discoloration and odor on storage, non-sandy and nonirritating to the skin. The superfatted soap bars contain from about 40% to about 60%, and preferably about 48%, by weight of a mixture in the relative proportions of from about 10% to about 30% by weight of potassium coconut oil soap and from about to about 70% by weight respectively of sodium coconut oil soap. The preferred mixture consists of from about 5% to about 10% by weight of potassium coconut oil soap and from about 43% to about 38% by weight respectively of sodium coconut oil soap. A minimum of 40% by weight total of coconut oil soap is required in order that the soap bars will be high lathering. However, more than 60% by weight total of coconut oil soap is unnecessary and would require impractical high levels of the in situ formed free fatty acid superfatting agent to provide acceptable mildness. The above relative amounts of potassium coconut oil soap and sodium coconut oil soap are necessary, because if too small a proportion of potassium coconut oil soap is used, the finished bars will be sandy while if too high a proportion of potassium coconut oil soap is used, the bars will be too soft and have an excessive wear rate.

A further essential component of the superfatted soap bars is from about 10% to about 35% by weight, and preferably about 16% by weight, of sodium tallow soap. The amounts thereof are not critical.

A further component of the soap bars of the invention is from about 10% to about 15% by weight, and preferably about 15% by weight, of coconut oil and tallow fatty acids which are formed in situ by interreaction of the acidulating agent with the coconut oil and tallow soaps as discussed above. These fatty acid superfatting agents impart mildness to the soap bars and render them non-irritating to the skin. The level of free fatty acids should be increased as the level of coconut oil soaps is increased. When the quantity of free fatty acid exceeds 15 by weight, however, the bars tend to be too soft for satisfactory processing and when 20% or more free fatty acid is used, the latherability is decreased.

Another component of the soap bars is from about 3% to about 10% by weight, and preferably about 8% by weight, of a higher sodium content salt of the acidulating agent discussed above having a pH above 7 which is formed as the by-product from the interreaction of the acidulating agent with the coconut oil and tallow soaps. Such sodium salts include, for example, disodium monohydrogen orthophosphate (Na HPO as the by-product of either or-thophosphoric acid or monosodium dihydrogen orthophosphate and trisodium monohydrogen pyrophosphate (Na HP O as the by-product of either pyrophosphoric acid or disodium dihyd rogen pyrophosphate. Such in situ formed sodium salts help impart firmness as well as color and odor stability to the soap bars. It will be appreciated that small amounts of the corresponding potassium salts are also present in the soap bars due to the interreaction of the acidulating agent with the potassium coconut oil soap.

'The remaining essential component of the soap bars is from about 5% to about 12% by weight, and preferably about by weigh-t, of water which constitutes the moisture content of the soap bars after drying the aqueous blend. The amount of moisture present in the soap bars is governed by the satisfactory processing properties of the bars, such as extrudability.

T-he superfatted soap bars of the invention and the process for their preparation are further illustrated by the following examples.

EXAMPLE 1 The soap boil was prepared containing 3804 pounds of sodium coconut oil soap and 1523 pounds of sodium tallow soap. The next soap from the boil was then pumped to a crutcher where 835 pounds of coconut oil fatty acid were added followed by neutralization thereof with 225 pounds of potassium hydroxide (KOH). At this point small amounts of preservatives, namely Versene (the tetrasodium salt of ethylene diamine tetraacetic acid) and butyl hydroxy toluene (BH-T), were added. 665 pounds of monosodium dihydrogen orthophosphate was then added. After a short mixing period, the crutcher slurry was dried in a tubular dryer to about 10% moisture. The molten soap was then chill rolled and the dried chips fed to a chip mixer where small amounts of perfume and other minor ingredients, such as whiteners or colorants etc., were added. The mixed chips were then milled, plodded and stamped into bars by conventional means.

The resultant superfatted soap bar had the following composition:

Components: Percent by weight Sodium coconut oil soap 38.35 Potassium coconut oil soap 10.00 Sodium tallow soap 16.12

nut oil fatty acids and 30% tallow fatty Free fatty acids (approximately 70% coconut oily fatty acids and 30% tallow fatty The following example illustrates a further use of the monosodium dihydrogen orthophosphate of Example 1 as the acidulating agent.

4 EXAMPLE 2 To a steam jacketed mixer with sigma blade agitator, the following were added, in the order given, with acket steam pressure at 10 p.s.i.g.:

Lbs.

Whole coconut oil fatty acids 14.0

BHT, 9.6 gms.

Versene (25% aqueous solution), 38.0 gms.

KOH (45% aqueous solution) 2.6

/20 sodium tallow/coconut oil soap chips at NaH PO 2.3 NaOH (50% aqueous solution) 3.6

When the last of .the ingredients had been added, the steam pressure was raised to 40 p.s.i.g. after which heat and agitation were continued until the resultant mixture had a water content of about 9%. The mixture was then chill rolled into chips. The chips were processed into bars after the addition of small amounts of TiO and perfume in a chip mixer followed by milling and plodding by conventional means.

The resultant soap bar had the following composition exclusive of the small amounts of titanium dioxide and perfume:

Components: Percent by weight Sodium coconut oil soap 35.0 Potassium coconut oil soap 15.0 Sodium tallow soap 19.2 Free fatty acids (from coconut oil soap and tallow soap) 15.0 Disodium monohydrogen orthophosphate 7.8 Water 8.0

Total 100.0

The following example illustrates the use of orthophosphoric acid as the acidulating agent.

EXAMPLE 3 The same processing conditions and equipment of Example 2 were used in this example. The following materials were added to the mixer in the order given:

Lbs.

Whole coconut oil fatty acids 9.8

BHT, 9.6 gms Versene (25% aqueous solution), 38.0 gms KOH (45.5% aqueous solution) 2.1

NaOH (50% aqueous solution) 2.4

80/20 sodium tallow/coconut oil soap chips at 14% H O 22.3 H PO (80% aqueous solution) 1.19

Ponents: Percent by weight Sodium coconut oil soap 28,0 Potassium coconut oil soap 12.0 Sodinmtallow soap 33.1 Free fatty acids (from coconut oil soap and tallow soap) 15.0 Disodium monohydrogen orthophosphate 3.9 Water 8.0

Total 100.0

The following example illustrates the use of disodium dihydrogen pyrophosphate as the acidulating agent.

EXAMPLE 4 The same processing conditions and equipment of Example 2 were employed in this example. The following materials were added to the mixer in the order given:

Components: Percent by weight Sodium coconut oil soap 33.0 Potassium coconut oil soap 7.0 Sodium tallow soap 30.6 Free fatty acids (from coconut oil soap and tallow soap) 10.0 N33HP207 Water 10.0

Total 100.0

All of the above bars produced a high lather and were firm and stable on storage against discoloration and odor. The bars were also non-sandy and non-irritating to the skin. Comparable results were obtained using other phosphorus-containing inorganic acidic compounds having a pH below 7 as the acidulating agent.

It will be appreciated that various compatible adjuvants may be present in the superfatted soap bars of the invention. Typical examples thereof include perfumes, whiteners, fluorescent dyes, preservatives, chelating agents, etc. Such compatible adjuvants, when employed, are present in small amounts of under a total of about 5% by weight of the bar.

Since various modifications of the product and process of the invention, in addition to those discussed above, would readily occur to those skilled in the soap art without departing from the spirit of the invention, the invention is to be limited only within the scope of the appended claims.

What is claimed is:

1. A process for the preparation of high lathering, firm, stable, non-sandy, non-irritating superfatted soap bars which comprises preparing and mixing an aqueous blend consisting essentially of from about 25% to about 55% by weight of a mixture in the relative amounts of from about to about 30% by weight of potassium coconut oil soap and from about 90% to about 70% by weight respectively of sodium coconut oil soap, from about 5% to about 30% by weight of sodium tallow soap, from about 2% to about 8% by weight of a phosphorus-containing inorganic acidic compound having a pH below 7 selected from the group consisting of orthophosphoric acid, pyrophosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid, triphosphoric acid, tetraphosphoric acid and strong acid salts thereof as an acidulating agent and from about 28% to about 45% by weight of water; drying the aqueous blend to a moisture content of from about 5% to about 12% by weight; and forming the dried blend into soap bars; whereby a portion of the coconut oil and tallow soaps are acidulated to liberate in situ the free fatty acids thereof and the acidulating agent is converted in part into a higher sodium content salt thereof having a pH above 7.

2. The process as defined by claim 1 wherein the acidulating agent is orthophosphoric acid.

3. The process as defined by claim 1 wherein the acidulating agent is monosodium dihydrogen orthophosphate.

4. The process as defined by claim 1 wherein the acidulating agent is disodium dihydrogen pyrophosphate.

5. A high lathering, firm, stable, non-sandy, non-irritating, superfatted soap bar for-med by the process of claim 3 consisting essentially of (a) from about 40% to about 60% by weight of a mixture in the relative amounts of from about 10% to about 30% by weight of potassium coconut oil soap and from about 90% to about by weight respectively of sodium coconut oil soap; (b) from about 10% to about 35% by weight of sodium tallow soap; (0) from about 10% to about 15% by weight of in situ formed coconut oil and tallow fatty acids; ((1) from about 3% to about 10% by weight of a higher sodium content salt having a pH above 7 of a phosphorous-containing inorganic acid compound having a pH below 7; selected from the group consisting of orthophosphoric acid, pyrophosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid, tn'phosphoric acid, tetraphosphoric acid and strong acid salts thereof and (e) from about 5% to about 12% by weight of water.

6. A high lathering, firm, stable, non-sandy, non-irritating, superfatted soap bar formed by the process of claim 3 consisting essentially of (a) about 48% by weight of a mixture consisting of from about 5% to about 10% by weight of potassium coconut oil soap and from about 43% to about 38% by weight respectively of sodium coconut oil soap; (b) about 16% by weight of sodium tallow soap; (c) about 15% by weight of in situ formed coconut oil and tallow fatty acids; (d) about 8% by weight of disodium monohydrogen orthophosphate; and

(e) about 10% by weight of water.

References Cited UNITED STATES PATENTS 2,093,927 9/ 1937 Preston 252109 2,310,475 2/ 1943 Thomas 252109 3,047,509 7/ 1962 Alsbury et al. 252-117 3,224,976 12/ 1965 Farrar 252119 3,383,320 5/1968 Bell 252132 3,247,121 4/ 1966 Hendricks 2521 17 FOREIGN PATENTS 521,566 5/ 1940 Great Britain.

LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT, Assistant Examiner US. Cl. X.R. 252132 "H050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, #94,869 Dated February 10, 1970 Inv n fl .TnsPph Armstrong It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 55, "nut oil fatty acids and 30% tallow fatty" should be deleted; line 57', oily should be oil line 59, "monohydrates should be monohydrogen Column 4, line 9, "45%" should be 45.5%

SIGNED AN'D SEALED Juu41970 Attest:

Edward M. Fletcher, Ir WILLIAM E. 30mm, JR.

Golrmissioner of Patents Attesting Officer