Title:
SOAP BAR
United States Patent 3625903
Abstract:
The discoloration of certain antibacterial compounds, halogenated o-hydroxydiphenyl ethers of the general formula ##SPC1##
US Patent References:
Soap bar compositions
Kelly - July 1962 - 3043778
Color stabilizers for detergents containing bacteriostats
Mitoray et al. - March 1963 - 3085066
Stabilization of soap compositions
Zussman - November 1966 - 3284362
Soap bar compositions
Kelly - July 1962 - 3043778
Color stabilizers for detergents containing bacteriostats
Mitoray et al. - March 1963 - 3085066
Stabilization of soap compositions
Zussman - November 1966 - 3284362
Inventors:
Davies, James Francis (Bromborough, EN)
Cheng, Wai Ming (Ellesmere Port, EN)
Cheng, Wai Ming (Ellesmere Port, EN)
Application Number:
04/721610
Publication Date:
12/07/1971
Filing Date:
04/16/1968
View Patent Images:
Export Citation:
Assignee:
Lever Brothers Company (New York, NY)
Primary Class:
Other Classes:
510/153, 514/721, 510/388
International Classes:
C11D3/48; C11D3/48
Field of Search:
252/106,107 424/172,340
Primary Examiner:
Rosdol, Leon D.
Assistant Examiner:
Willis P. E.
Claims:
What is claimed is
1. An antibacterial toilet soap bar consisting essentially of, by weight, between 0.1 and 5 percent of an antibacterial compound of the general formula
2. An antibacterial soap bar as claimed in claim 1, in which the antibacterial compound is 4,2',4'-trichloro-2-hydroxydiphenylether.
3. An antibacterial soap bar as claimed in claim 1, in which the antibacterial compound is 4,4'-dichloro-2-hydroxydiphenylether.
1. An antibacterial toilet soap bar consisting essentially of, by weight, between 0.1 and 5 percent of an antibacterial compound of the general formula
2. An antibacterial soap bar as claimed in claim 1, in which the antibacterial compound is 4,2',4'-trichloro-2-hydroxydiphenylether.
3. An antibacterial soap bar as claimed in claim 1, in which the antibacterial compound is 4,4'-dichloro-2-hydroxydiphenylether.
Description:
This invention relates to antibacterial soap bars.
Amongst the many classes of antibacterial compounds that have been recommended for use in toilet soap bars are a number of classes of halogenated phenols. Unfortunately many such phenolic compounds when incorporated into soap bars cause the bars to discolor when they are exposed to sunlight. Discoloration occurs even though usual preservatives such as chelating agents, e.g., ethylenediamine tetraacetic acid and free-radical inhibitors are incorporated in the bar.
Halogenated phenols that have this disadvantage include halogenated o-hydroxydiphenyl ethers of the general formula:
in which, independently, X 1 and X 3 are halogen, X and X 2 are hydrogen or halogen and p is a whole number from 1 to 5. Preferred halogens are bromine and chlorine, in particular chlorine.
It has now been discovered that when compounds of the above general formula are included in bars together with at least 1 percent of free fatty acid color deterioration in the bar is surprisingly reduced. The upper limit on the amount of fatty acid is about 15 percent, where the physical properties of the soap bar begin to be unduly affected.
Preferably X 2 should be halogen and preferable should be ortho to the ether group (p=2 in this case).
A mixture of antibacterial compounds can be used, e.g., a mixture of compounds within the general formula or a mixture with other antibacterial compounds.
The amount of antibacterial compound of the above general formula can be between 0.1 and 5 percent by weight of the bar, preferably between 0.1 and 2 percent. The total amount of antibacterial compound or compounds in the bar will normally be between 0.5 and 5 percent, preferably 0.5 to 2 percent, by weight of the bar.
The invention therefore provides an antibacterial soap bar containing an antibacterial compound of the class herein defined and from 1 to 15 percent by weight of free fatty acid. The bar should preferably contain between 2 and 10 percent by weight of free fatty acid.
The free fatty acid should be a C 8 -C 22 substantially straight-chain fatty acid and can advantageously be such an acid as stearic acid or myristic acid or mixtures of acids derived from coconut oil, tallow fat or palm kernel oil. Such fatty acid is a usual superfatting agent.
The antibacterial compound or compounds and the free fatty acid may be incorporated in any convenient manner either independently or together. The fatty acid can be released in the bar or soap from which the bar is made, for instance by the use of phosphoric acid as described in Netherlands application No. 6,709,575.
The invention is particularly applicable to 4,2',4'-trichloro-2-hydroxydiphenylether where, in the general formula, X 1 , X 2 and X 3 are chlorine, X is hydrogen, p is 2 and X 2 is ortho.
Experiment 1
Soap mushes containing 1 percent, by weight of soap base, of 4,2',4'-trichloro-2-hydroxydiphenyl ether were prepared in beakers. The soap mush was formed from 10 g. of a soap base and 50 g. of water. The soap base was prepared from an 80/15/5 tallow/coconut/sperm oil distillate fat charge. Into separate mushes were incorporated, by weight of soap base, 0.5 percent of benzoic acid, 2 percent of palm kernel acid, 5 percent of palm kernel acid and 10 percent of palm kernel acid. The beakers were exposed to direct sunlight and the time taken for discoloration of the soap mushes to occur was noted. Benzoic acid was used since it is disclosed as a stabilizer for such compounds in U.S. Pat. No. 3,284,362. The following results were obtained:
Additive in soap % in soap Time to discoloration of mush soap mush after exposure to direct sunlight-- days ____________________________________________________________ ______________ -- -- <1 Benzoic acid 0.5 1 Palm Kernel acid 2 3+ Palm kernel acid 5 7+ Palm kernel acid 10 7+ ____________________________________________________________ ______________
Experiment 2
soap bars were made from the soap base used in experiment 1 containing 1 percent by weight of 4,2',4'-trichloro-2-hydroxydiphenyl ether. Into one set of soap bars was incorporated 2 percent by weight of palm kernel acid and into another bar 5 percent by weight of palm kernel acid. The time taken for discoloration of the soap bars to occur was measured when the bars were exposed to direct sunlight. The following results were obtained:
Additive in soap Time to discoloration of bar % in soap bar soap bar--weeks ____________________________________________________________ ______________ -- -- <1 day Palm kernel acid 2 3 Palm kernel acid 5 3+ ____________________________________________________________ ______________
Experiment 3
soap bars were prepared according to experiment 2 but instead of 4,2',4'-trichloro-2-hydroxydiphenylether the bars contained 3,5,6,3',5',6' -hexachloro-2,2'-dihydroxydiphenyl methane and a mixture of 3,5,4' -tribromosalicylanilide (60percent) and 5,4'-dibromosalicylanilide (40percent). It was found that bars containing these antibacterial compounds were not stabilized against discoloration by incorporation of fatty acid in the bar.
Experiment 4
soap bars were prepared according to experiment 2 but instead of 4,2',4'-trichloro-2-hydroxydiphenylether the bars contained 4,4'-dichloro-2-hydroxydiphenylether. Similar results were obtained.
Experiment 5
five sets of soap bars were prepared. All contained 1 percent of 4,2',4'-trichloro-2-hydroxydiphenylether. The five sets contained, respectively, 0.1 percent benzoic acid, 1 percent benzoic acid, 2.8 percent benzoic acid, 5 percent benzoic acid and 5 percent palm kernel acid, 2.8 percent benzoic acid is, on a molar basis, equivalent to 5 percent palm kernel acid.
After exposure to daylight the following results were obtained:
Additive % Color ____________________________________________________________ ______________ Benzoic acid 0.1 Very bad Benzoic acid 1 Bad Benzoic acid 2.8 Poor Benzoic acid 5.0 Poor Palm kernel acid 5.0 Good ____________________________________________________________ ______________
It was also found that the physical properties of the bar, softness, etc., were poorer with the bars containing more than 2 percent by weight of benzoic acid than with the other bars.
Experiment 6
soap bars were prepared containing 0.1, 0.2, 0.3 and 0.5 percent of 4,2',4'-trichloro-2-hydroxydiphenylether, respectively, and various amounts of fatty acid superfat. Although some stabilization of colour occurs at lower levels and ratios of superfat, it was found that preferably there should be at least 1 percent of superfat present in the bar and the weight ratio of superfat to antibacterial compound should be greater than 4:1.
Amongst the many classes of antibacterial compounds that have been recommended for use in toilet soap bars are a number of classes of halogenated phenols. Unfortunately many such phenolic compounds when incorporated into soap bars cause the bars to discolor when they are exposed to sunlight. Discoloration occurs even though usual preservatives such as chelating agents, e.g., ethylenediamine tetraacetic acid and free-radical inhibitors are incorporated in the bar.
Halogenated phenols that have this disadvantage include halogenated o-hydroxydiphenyl ethers of the general formula:
in which, independently, X 1 and X 3 are halogen, X and X 2 are hydrogen or halogen and p is a whole number from 1 to 5. Preferred halogens are bromine and chlorine, in particular chlorine.
It has now been discovered that when compounds of the above general formula are included in bars together with at least 1 percent of free fatty acid color deterioration in the bar is surprisingly reduced. The upper limit on the amount of fatty acid is about 15 percent, where the physical properties of the soap bar begin to be unduly affected.
Preferably X 2 should be halogen and preferable should be ortho to the ether group (p=2 in this case).
A mixture of antibacterial compounds can be used, e.g., a mixture of compounds within the general formula or a mixture with other antibacterial compounds.
The amount of antibacterial compound of the above general formula can be between 0.1 and 5 percent by weight of the bar, preferably between 0.1 and 2 percent. The total amount of antibacterial compound or compounds in the bar will normally be between 0.5 and 5 percent, preferably 0.5 to 2 percent, by weight of the bar.
The invention therefore provides an antibacterial soap bar containing an antibacterial compound of the class herein defined and from 1 to 15 percent by weight of free fatty acid. The bar should preferably contain between 2 and 10 percent by weight of free fatty acid.
The free fatty acid should be a C 8 -C 22 substantially straight-chain fatty acid and can advantageously be such an acid as stearic acid or myristic acid or mixtures of acids derived from coconut oil, tallow fat or palm kernel oil. Such fatty acid is a usual superfatting agent.
The antibacterial compound or compounds and the free fatty acid may be incorporated in any convenient manner either independently or together. The fatty acid can be released in the bar or soap from which the bar is made, for instance by the use of phosphoric acid as described in Netherlands application No. 6,709,575.
The invention is particularly applicable to 4,2',4'-trichloro-2-hydroxydiphenylether where, in the general formula, X 1 , X 2 and X 3 are chlorine, X is hydrogen, p is 2 and X 2 is ortho.
Experiment 1
Soap mushes containing 1 percent, by weight of soap base, of 4,2',4'-trichloro-2-hydroxydiphenyl ether were prepared in beakers. The soap mush was formed from 10 g. of a soap base and 50 g. of water. The soap base was prepared from an 80/15/5 tallow/coconut/sperm oil distillate fat charge. Into separate mushes were incorporated, by weight of soap base, 0.5 percent of benzoic acid, 2 percent of palm kernel acid, 5 percent of palm kernel acid and 10 percent of palm kernel acid. The beakers were exposed to direct sunlight and the time taken for discoloration of the soap mushes to occur was noted. Benzoic acid was used since it is disclosed as a stabilizer for such compounds in U.S. Pat. No. 3,284,362. The following results were obtained:
Additive in soap % in soap Time to discoloration of mush soap mush after exposure to direct sunlight-- days ____________________________________________________________ ______________ -- -- <1 Benzoic acid 0.5 1 Palm Kernel acid 2 3+ Palm kernel acid 5 7+ Palm kernel acid 10 7+ ____________________________________________________________ ______________
Experiment 2
soap bars were made from the soap base used in experiment 1 containing 1 percent by weight of 4,2',4'-trichloro-2-hydroxydiphenyl ether. Into one set of soap bars was incorporated 2 percent by weight of palm kernel acid and into another bar 5 percent by weight of palm kernel acid. The time taken for discoloration of the soap bars to occur was measured when the bars were exposed to direct sunlight. The following results were obtained:
Additive in soap Time to discoloration of bar % in soap bar soap bar--weeks ____________________________________________________________ ______________ -- -- <1 day Palm kernel acid 2 3 Palm kernel acid 5 3+ ____________________________________________________________ ______________
Experiment 3
soap bars were prepared according to experiment 2 but instead of 4,2',4'-trichloro-2-hydroxydiphenylether the bars contained 3,5,6,3',5',6' -hexachloro-2,2'-dihydroxydiphenyl methane and a mixture of 3,5,4' -tribromosalicylanilide (60percent) and 5,4'-dibromosalicylanilide (40percent). It was found that bars containing these antibacterial compounds were not stabilized against discoloration by incorporation of fatty acid in the bar.
Experiment 4
soap bars were prepared according to experiment 2 but instead of 4,2',4'-trichloro-2-hydroxydiphenylether the bars contained 4,4'-dichloro-2-hydroxydiphenylether. Similar results were obtained.
Experiment 5
five sets of soap bars were prepared. All contained 1 percent of 4,2',4'-trichloro-2-hydroxydiphenylether. The five sets contained, respectively, 0.1 percent benzoic acid, 1 percent benzoic acid, 2.8 percent benzoic acid, 5 percent benzoic acid and 5 percent palm kernel acid, 2.8 percent benzoic acid is, on a molar basis, equivalent to 5 percent palm kernel acid.
After exposure to daylight the following results were obtained:
Additive % Color ____________________________________________________________ ______________ Benzoic acid 0.1 Very bad Benzoic acid 1 Bad Benzoic acid 2.8 Poor Benzoic acid 5.0 Poor Palm kernel acid 5.0 Good ____________________________________________________________ ______________
It was also found that the physical properties of the bar, softness, etc., were poorer with the bars containing more than 2 percent by weight of benzoic acid than with the other bars.
Experiment 6
soap bars were prepared containing 0.1, 0.2, 0.3 and 0.5 percent of 4,2',4'-trichloro-2-hydroxydiphenylether, respectively, and various amounts of fatty acid superfat. Although some stabilization of colour occurs at lower levels and ratios of superfat, it was found that preferably there should be at least 1 percent of superfat present in the bar and the weight ratio of superfat to antibacterial compound should be greater than 4:1.