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(11) | EP 0 195 663 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Bleaching compositions |
| (57) This invention relates to bleaching compositions that provide effective and efficient
surface bleaching of textiles over a wide range of bleach solution temperatures. The
compositions of the invention yield a C10-C15 peroxyacid when used in bleaching compositions with low ionic strength, and which
are substantially free of cationic surfactants. In a preferred embodiment, the bleaching
compositions of the invention are detergent compositions. |
BACKGROUND OF THE INVENTION
Technical Field
[0001] This invention relates to peroxygen bleaching compositions and processes therefor that provide effective surface bleaching of textiles over a wide range of temperatures. Surface bleaching of textiles is bleaching wherein the bleaching mechanism takes place on the textile surface, and, thereby, removes stains and/or soils.
SUMMARY OF THE INVENTION
[0002] The present invention relates to a bleaching composition comprising a compound which will provide in aqueous solution a peroxyacid of the general formula:
wherein R is an alkyl group containing from about 10 to 20 Preferred compounds which provide the above perox- about 15 carbon atoms. The bleaching solution has an ionic yacid are the magnesium salts thereof. Such salts have the strength of no more than 0.05M and is substantially free of following general formula: cationic surfactants.
wherein R is as defined for the peroxyacid, X is a compatible anion, n is 1 or 2 and Y is from 0 to about 6.
[0003] The peroxyacids may also be formed in situ from a peroxygen bleaching compound capable of yielding hydrogen peroxide and a bleach activator of the following formula
where R is as defined for the peroxyacid and L is a leaving group, hereinafter defined.
[0004] Where the composition contains the bleach activator, another essential component is a peroxygen bleaching compound capable of yielding hydrogen peroxide in aqueous solution: In a preferred embodiment, the bleaching compositions are incorporated into detergent compositions.
[0005] The invention also relates to a process for bleaching textiles with one of the above described compounds.
Detailed Description of The Invention
[0006] This invention relates to bleaching compositions comprising compounds which provide peroxyacids of the following formula
wherein R is an alkyl group with from about 10 to about 15, and preferably about 11 carbon atoms. When used under the conditions of the invention, they provide effective and efficient surface bleaching of textiles and porcelain which thereby removes stains and/or soils from textiles and porcelain.
[0007] The bleaching compositions of the invention provide bleaching over a wide range of solution temperatures. Bleaching is obtained in bleach solutions wherein the solution temperature is at least 5°C.
[0008] The compounds providing the peroxyacids in the compositions of the invention may be synthesized from natural raw materials such as coconut extract which is predominen- tly lauric acid. These compounds are essentially odor free as compared with shorter chain, more volatile homologues. Because of the low cost of the raw materials, the compounds are also more economical to use.
[0009] The peroxyacid may be used directly as a bleaching agent in compositions of the invention under the proper conditions, as hereinafter defined. For improved stability, especially when incorporated into detergent compositions, the magnesium salt of the peroxyacid is preferred. Alternatively, a bleach activator may be employed with a peroxygen bleaching compound capable of releasing hydrogen peroxide.
[0011] The magnesium salt has the following general formula:
wherein R is an alkyl group containing from about 10 to about 15, and preferably about 11 carbon atoms, n is 1 or 2, and X is a compatible anion.
[0012] In a preferred form, the magnesium salt is a hydrate of the following formula:
wherein R, n and X are as defined above and Y is from about 1 to 6, and preferably 4.
[0013] The magnesium compounds are solid and possess excellent storage stability, especially under alkaline conditions such as when admixed with a detergent composition. Stability means that the solid magnesium peroxycarboxylates retain the active oxygen during storage to a much greater extent than the corresponding peroxyacids. The active oxygen in the magnesium peroxycarboxylate is readily available. This means that the solid magnesium peroxycarboxylates are readily soluble or dispersible and yield solutions containing active oxygen. When the solution is aqueous, it cannot be distinguished from an aqueous solution prepared from the corresponding peroxyacid and an equivalent amount of magnesium, when the solutions are adjusted to the same pH.
[0014] The magnesium peroxycarboxylates are safer than the corresponding peroxyacids both for handling purposes and to the substrate. Also the solid magnesium peroxycarboxylates have superior odor, dispersibility and handling properties relative to the corresponding peroxyacids.
[0015] It is believed that the increased stability of the magnesium salt relative to the primary peroxyacid is due to the fact that the active oxygen atom is nucleophilic rather than electrophilic as it is in the corresponding peroxyacid. Nucleophilic agents which would attack an electrophilic oxygen are much more prevalent in bleaching and detergent compositions than electrophilic agents.
[0016] The magnesium peroxycarboxyiates are prepared via the process of U.S. Patent 4,483,781, Hartman, issued November 20, 1984, incorporated herein by reference. Hartman discloses magnesium salts of peroxyacids containing alkyl groups of from Cl-C2..
[0017] Contrary to the teachings of the prior art, however, the compounds of the C,o-C,5 chain length possess excellent bleaching ability and are virtually free of malodor when used in compositions involving an ionic strength of no more than 0.05M, preferably no more than 0.03M, and an absence of cationic surfactants.
[0019] The bleach activators within the invention have the following general formula:
wherein R is as defined for the peroxyacid and L is a leaving group.
[0020] The leaving group L should be electron withdrawing in order to increase the reactivity of the carbonyl moiety. L must be sufficiently reactive for the perhydolysis, hereinafter defined, to occur within the optimum time frame (e.g., a wash cycle). However, if L is too reactive the bleach activator will be difficult to stabilize for use in a bleaching or detergent composition. It is also important that L form a stable entity after "leaving" so that the back reaction. will occur at a negligible rate.
[0021] These attributes are generally paralleled by the pKa of the conjugate acid, HL, of the leaving group, L, although exceptions to this convention are known. Generally, suitable leaving groups possess pKa's of their conjugate acid in the range of from about 4 to about 13, preferably from about 7 to 11, and most preferably from about 8 to 11.
[0022] L should also contain a water solubilizing group, Y, so that the dissolution of the bleach activator proceeds expeditiously.
[0023] Preferred bleach activators are those of the above general formula wherein R is as defined in the general formula and L is selected from the group consisting of:
wherein R is as defined above, R2 is an alkyl chain containing from about 1 to about 8 carbon atoms, R3 is H or R2, and Y is H or a solubilizing group. The preferred solubilizing groups are -SO 3 M+, -COO-M+, -SO- 4 M+, (-N+R34)X-and O - N(R24)-and most preferably -SO 3 M+ and -COO- M+ wherein R is an alkyf chain containing from about 1 to about 4 carbon atoms, M is a cation which provides solubility to the bleach activator and Y is an anion which provides solubility to the bleach activator. Preferably, M is an alkali metal, ammonium or substituted ammonium cation, with sodium and potassium being most preferred. It should be noted that bleach activators with a leaving group that does not contain a solubilizing group should be well dispersed in the bleaching solution in order to assist in their dissolution.
[0024] Preferred bleach activators are also those of the above general formula wherein L is as defined in the general formula and R is an alkyl group containing about 11 carbon atoms.
[0025] Particularly preferred bleach activators are those of the above general formula wherein R is an alkyl group containing from about 10 to about 15 carbon atoms and L is selected from the group consisting of:
wherein R2 is as defined above and Y is -SO 3 M+ or COO-M+> wherein M is as defined above.
[0026] Especially preferred bleach activators are those of the above general formula wherein R is a linear alkyl chain containing about 11 carbon atoms and L is selected from the group consisting of:
wherein R' is as defined above, Y is -SO 3 M+ or - 20 The most preferred bleach activators have the formula: COO-M+, and M is as defined above.
or
wherein R is a linear alkyl chain containing about 11 carbon atoms and M is sodium or potassium.
[0027] The bleaching compositions of the invention are those which, upon dissolution in aqueous solution, provide a bleaching compound of the formula
[0028] The bleaching compositions of the invention provide surface bleaching over a wide range of bleach solution temperatures. Such bleaching is obtained in bleach solutions wherein the solution temperature is at least about 5°C. Peroxygen bleaches would be ineffective and/or impracticable at temperatures below about 60°C.
[0029] Optimum surface bleaching performance is obtained with bleaching solutions wherein the pH of such solution is between about 8.5 and 11.0 and preferably between 9.5 and 10.5. It is preferred that such pH be greater than 9 to increase the concentration of perhydroxyl anion present. Such pH can be obtained with substances commonly known as buffering agents, which are optional components of the bleaching compositions herein.
[0030] The bleaching mechanism generally, and the surface bleaching mechanism in particular, are not completely understood. However, it is generally believed that the bleach activator undergoes nucleophilic attack by a perhydroxyl anion, which is generated from the hydrogen peroxide evolved by the peroxygeh bleach, to form a peroxycarboxylic acid. This reaction is commonly referred to as perhydrolysis.
[0031] A second, less desirable reaction involves the formation of the less reactive diacyl peroxide. The latter reaction increases in consequence with the hydrophobicity of the R group. However, the extent of desirable surface bleaching also increases with the hydrophobicity of the R group.
[0032] The generation of the less reactive diacyl peroxide can be minimized by increasing the amount of the perhydroxyl anion present in the bleaching solution. Since the perhydroxyl anion is the perhydrolysis agent, this accelerates the perhydrolysis of the bleach activator. The diacyl peroxide will also perhydrolize to regenerate the more reactive peroxyacid. This vastly increases the bleaching efficiency of the bleaching solution.
[0033] The amount of perhydroxyl anion may be increased directly by adding more alkalinity to the bleaching solution.
[0034] U.S. Patent 4,412,934, Chung et aI issued November 1, 1983, incorporated herein by reference teaches that R groups of the length described (C10-C15) will not form useful amounts of peroxyacids.
[0035] Likewise, in Recueil 1966, 85. page 75, L. Heslinga and W. Schwaiger state that lauroyl peroxide will not react with the perhydroxyl anion.
[0036] A second mechanism for the generation of diacyl peroxide involves the combination of two peroxy acid molecules, as disclosed by J.F. Goodman et al in Trans. Farad. Soc. 1962. 58. 1846-1851. This undesirable reaction occurs even in the absence of bleach activators. This reaction also increases in consequence with the hydrophobicity of the R group.
[0037] Applicant has now surprisingly found that bleach activators of the invention wherein R is an alkyl chain with about 10 to about 15 carbon atoms will undergo perhydrolysis to form and maintain useful amounts of peroxyacids. This requires that the ionic strength of the solution be from about 0 to about 0.05M, preferably from about 0 to about 0.03M. The ionic strength must be decreased for effective bleaching as the chain length of R increases. For R containing from about 13 to about 15, the ionic strength is preferably .025M or less, most preferably about 0.01M. The same considerations are operative for the peroxy acids within this invention.
[0038] The bleaching compositions of the invention are substantially free of cationic surfactant such as those described in U.S. Patent 4,222,905, Cockrell, issued September 6, 1980 and in U.S. Patent 4,239,659, Murphy, issued December 16, 1980, both incorporated herein by reference.
[0039] Where cationic surfactants are present, they form less than 0.5%, preferably less than 0.2% by weight of the surfactant present Inclusion of more than the stated limits of cationic surfactant results in excessive formation of the corresponding diacyl peroxide and attendant loss of bleaching performance.
[0040] Without being bound by theory it is believed that diacyl peroxide formation, hereinabove described, tends to dominate when R is longer than about 10 carbon atoms and the ionic strength is greater than about 0.05M and/or cationic surfactants, are present. This is because the diacyl peroxide formed via either or both of the mechanisms described under these conditions precipitates or is micellized and is not accessible to the perhydroxyl anion. However, when the conditions of this invention are met, then the diacyl peroxide formed becomes accessible to the perhydroxyl anion and behaves like a bleach activator wherein L is RCO and generates the peroxycarboxylic acid as desired. It is believed that high ionic strength tends to drive the diacyl peroxide away from the aqueous phase containing the perhydroxyl anion and out of solution. When cationic surfactants are present with anionic surfactants, it is believed that the surfactant micelles entrap the diacyl peroxide in the hydrophobic micellar interior, again, away from the requisite perhydroxyl anion.
[0041] It is believed that the greater hydrophobic character of diacyl peroxides formed from the bleach activators and peroxyacids of this invention (wherein R consists of a carbon chain of about 10 to about 15 carbon atoms) accounts from this behavior. The lower homologous bleach activators and peroxyacids outside this invention are generally less affected by ionic strength or surfactant types. This is because the shorter R groups lead to more hydrophilic diacyl peroxides which remain accessible to the perhydroxyt anion even with higher levels of ionic strength and/or cationic surfactants. Thus it can be seen that the bleach activator or peroxyacid wherein R is 15 would be more affected than wherein R is 11. Thus, for a bleach activator or peroxyacid wherein R is 15, a lower ionic strength is required than when R is 11. However, it is believed that any peroxyacid, or bleach activator capable of generating a surface active peroxyacid will have a maximum ionic strength above which inaccessible diacyl peroxide formation dominates. Appropriate design of the bleaching composition, as described herein, ameliorates this condition.
The Peroxygen Bleaching Compound
[0042] The peroxygen bleaching compounds useful in the compositions containing bleach activators herein are those capable of yielding hydrogen peroxide in an aqueous solution. These compounds are well known in the art and include hydrogen peroxide and the alkali metal peroxides, organic peroxide bleaching compounds such as urea peroxide, and inorganic persatt bleaching compounds, such as the alkali metal perborates, percarbonates, perphosphates, and the like. Mixtures of two or more such bleaching compounds can also be used, if desired.
[0043] Preferred peroxygen bleaching compounds include sodium perborate, commercially available in the form of mono- , tri-and tetra-hydrate, sodium carbonate peroxyhydrate, sodium pyrophosphate peroxyhydrate, urea peroxyhydrate, and sodium peroxide.
[0044] Particularly preferred are sodium perborate tetrahydrate and, especially, sodium perborate monohydrate. Sodium perborate monohydrate is especially preferred because it is very stable during storage and yet still dissolves very quickly in the bleaching solution. It is believed that such rapid dissolution results in the formation of higher levels of percarboxylic acid and, thus, enhanced surface bleaching performance.
[0045] The level of peroxygen bleach within compositions of the invention is from about 0.1% to about 95% and preferably from about 1 % to about 60%. When the bleaching compositions within the invention are also detergent compositions it is preferred that the level of peroxygen bleach is from about 1 % to about 20%.
[0046] The level of bleach activator within the compositions of the invention is from about 0.1% to about 60% and preferably from about 0.5% to about 40%. When the bleaching compositions within the invention are also detergent compositions it is preferred that the level of bleach activator is from about .1% to about 10%, and preferably 1% to about 6%.
Optional Components
[0047] As a preferred embodiment, the bleaching compositions of the invention can be detergent compositions. Thus, the bleaching compositions can contain typical detergent composition components such as detergency surfactants and detergency builders. In such preferred embodiments the bleaching compositions are particularly effective, if the detergent composition has an ionic strength within the invention. The bleaching compositions of this invention can con- fain all of the usual components of detergent compositions including the ingredients set forth in U.S. Patent 3,936,537, Baskerville et al, incorporated herein by reference. Such components include color speckles, suds boosters, suds suppressors, antitamish and/or anticorrosion agents, soil- suspending agents, soil-release agents, dyes, fillers, optical brighteners, germicides, alkalinity sources, hydrotropes, antioxidants, enzymes, enzyme stabilizing agents, perfumes, etc.
[0048] The detergent surfactants can be any one or more surface active agents selected from anionic, nonionic, zwitterionic, amphoteric classes and compatible mixtures thereof. Detergent surfactants useful herein are listed in U.S. Patent 3,664,961, Norris, issued May 23, 1972, and in U.S. Patent 3,919,678, Laughlin et al, issued December 30, 1975, both incorporated herein by reference. The following are representative examples of detergent surfactants useful in the present compositions.
[0049] Water-soluble salts of the higher fatty acids, i.e., "soaps", are useful anionic surfactants in the compositions herein. This includes alkali metal soaps such as the sodium, potassium, ammonium, and alkanolammonium salts of higher fatty acids containing from about 8 to about 24 carbon atoms, and preferably from about 12 to about 18 carbon atoms. Soaps can be made by direct saponification of fats and oils or by the neutralization of free fatty acids. Particu- lady useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium tallow and coconut soap.
[0050] Useful anionic surfactants also include the water-soluble salts, preferably the alkali metal, ammonium and al- kylolammonium salts, of organic sulfuric reaction products having in their molecular structure an alkyl group containing from about 10 to about 20 carbon atoms and a sulfonic acid or sulfuric acid ester group. (included in the term "alkyl" is the alkyl portion of acyl groups.) Examples of this group of synthetic surfactants are the sodium and potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C.-C,, carbon atoms) such as those produced by reducing the glycerides of tallow or coconut oil; and the sodium and potassium alkylbenzene sulfonates in which the alkyl group contains from about 9 to about 15 carbon atoms, in straight chain or branched chain configuration, e.g., those of the type described in U.S. Patents 2,220,099 and 2,477,383. Especially valuable are linear straight chain alkylbenzene sulfonates in which the average number of carbon atoms in the alkyl group is from about 11 to 13, abbreviated as C11.13LAS.
[0051] Other anionic surfactants herein are the sodium alkyl glyceryl ether sulfonates, especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfates containing from about 1 to about 10 units of ethylene oxide per molecule and wherein the alkyl groups contain from about 8 to about 12 carbon atoms; and sodium or potassium salts of alkyl ethylene oxide ether sulfates containing about 1 to about 10 units of ethylene oxide per molecule and wherein the alkyl group contains from about 10 to about 20 carbon atoms.
[0052] Other useful anionic surfactants herein include the water-soluble salts of esters of alpha-sulfonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxyalkane-1-sulfonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; water-soluble salts of olefin and paraffin sulfonates containing from about 12 to 20 carbon atoms; and beta-alkyloxy alkane sulfonates containing from about 1 to 3 carbon atoms in the alkyl group and from about 8 to 20 carbon atoms in the alkan moiety.
[0053] Water-soluble nonionic surfactants are also useful in the compositions of the invention. Such nonionic materials include compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature. The length of the polyoxyalkylene group which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.
[0054] Suitable nonionic surfactants include the polyethylene oxide condensates of alkyl phenols, e.g., the condensation products of alkyl phenols having an alkyl group containing from about 6 to 15 carbon atoms, in either a straight chain or branched chain configuration, with from about 3 to 12 moles of ethylene oxide per mole of alkyl phenol.
[0055] Preferred nonionics are the water-soluble and water-dispersible condensation products of aliphatic alcohols containing from 8 to 22 carbon atoms, in either straight chain or branched configuration, with from 3 to 12 moles of ethylene oxide per mole of alcohol. Particularly preferred are the condensation products of alcohols having an alkyl group containing from about 9 to 15 carbon atoms with from about 4 to 8 moles of ethylene oxide per mole of alcohol.
[0056] Semi-polar nonionic surfactants include water-soluble amine oxides containing one alkyl moiety of from about 10 to 18 carbon atoms and two moieties selected from the group of alkyl and hydroxyalkyl moieties of from about 1 to about 3 carbon atoms; water-soluble phosphine oxides containing one alkyl moiety of about 10 to 18 carbon atoms and two moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to 3 carbon atoms; and water-soluble sulfoxides containing one alkyl moiety of from about 10 to 18 carbon atoms and a moiety selected from the group consisting of alkyl and hydroxyalkyl moieties of from about 1 to 3 carbon atoms.
[0057] Ampholytic surfactants include derivatives of aliphatic or aliphatic derivatives of heterocyclic secondary and tertiary amines in which the aliphatic moiety can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and at least one aliphatic substituent contains an anionic water- solubilizing group.
[0058] Zwitterionic surfactants include derivatives of aliphatic, quaternary, ammonium, phosphonium, and sulfonium compounds in which one of the aliphatic substituents contains from about 8 to 18 carbon atoms.
[0059] The compositions of the invention are substantially free of cationic surfactants, such as those desribed in U.S. Patent 4,222,905, Cockrell, issued September 6, 1980, and in U.S. Patent 4,239,659, Murphy, issued December 16, 1980 both incorporated herein by reference.
[0060] Where cationic surfactants are included, they comprise no more than about 0.5%, and preferably no more than about 0.2% by weight of the total surfactant in the composition. Preferably, any cationic surfactant present is in the form of a separate body, wherein the cationic is separated from other compounds of the composition by encapsulation prior to addition.
[0061] The level of detergent surfactant that can be employed is from 0% to about 50%, preferably from about 1 % to about 30% and most preferably from about 10% to about 25% by weight of the total composition.
[0062] In addition to detergent surfactants, detergency builders can be employed in the bleaching compositions. Water-soluble inorganic or organic electrolytes are suitable builders. The builder can also be water-insoluble calcium ion exchange materials; nonlimiting examples of suitable water-soluble, inorganic detergent builders include: alkali metal carbonates, borates, phosphates, bicarbonates and silicates. Specific examples of such salts include sodium and potassium tetraborates, bicarbonates, carbonates, orthophosphates, pyrophosphates, tripotyphosphates and metaphosphates.
[0063] Examples of suitable organic alkaline detergency builders include: (1) water-soluble amino carboxylates and aminopolyacetates, for example, nitrilotriacetates, glycinates, ethylenediamine tetraacetates, N-(2-hydroxyethyl)nitrilo diacetates and diethyfenetriamine pentaacetates; (2) water-soluble salts of phytic acid, for example, sodium and potassium phytates; (3) water-soluble polyphosphonates, including sodium, potassium, and lithium salts of ethane-1-hydroxy-1, 1-diphosphonic acid; sodium, potassium, and lithium salts of ethylene diphosphonic acid; and the like; (4) water-soluble polycarboxylates such as the salts of lactic acid, succinic acid, maionic acid, maleic acid, citric acid, carboxymethyfoxysuccinic acid, 2-oxa-1,1,3-propane tricarboxylic acid, 1,1,2,2-ethane tetracarboxylic acid, mellitic acid and pyromellitic acid; and (5) water-soluble polyacetals as disclosed in U.S. Patents 4,144,266 and 4,246,495 incorporated herein by reference.
[0064] Another type of detergency builder material useful in the present compositions comprises a water-soluble material capable of forming a water-insoluble reaction product with water hardness cations preferably in combination with a crystallization seed which is capable of providing growth sites for said reaction product Such "seeded builder" compositions are fully disclosed in British Patent Specification No. 1,424,406.
[0065] A further class of detergency builder materials useful in the present invention are insoluble sodium aluminosilicates, particularly those described in Belgian Patent 814,874, issued November 12,1974, incorporated herein by reference. This patent discloses and claims detergent compositions containing sodium aluminosilicates having the formula:
Na2(AIO2)z(SiO2)yXH2O
wherein z and y are integers equal to at least 6, the molar ratio of z to y is in the range of from 1.0:1 to about 0.5:1, and X is an integer from about 15 to about 264, said aluminosilicates having a calcium ion exchange capacity of at least 200 milligrams equivalent/gram and a calcium ion exchange rate of at least about 2 grains/gallon/minute/gram. A preferred material is Zeolite A which is:
Na12(SiO2AlO2)1227H2O
[0067] The level of detergency builder of the bleaching compositions is from 0% to about 70%, preferably from about 10% to about 60% and most preferably from about 20% to about 60%.
[0068] Buffering agents can be utilized to maintain the desired alkaline pH of the bleaching solutions. Buffering agents include, but are not limited to many of the detergency builder compounds disclosed hereinbefore. Buffering agents suitable for use herein are those well known in the detergency art
[0069] Preferred optional ingredients include suds modifiers particularly those of suds suppressing types, exemplified by silicones, and silica-silicone mixtures.
[0070] U.S. Patents 3,933,672, issued January 20, 1976 to Bartolotta et al, and 4,136,045, issued January 23, 1979 to Gault et al, incorporated herein by reference, disclose silicone suds controlling agents. The silicone material can be represented by alkylated polysiloxane materials such as silica aerogels and xerogets and hydrophobic silicas of various types. The silicone material can be described as siloxane having the formula:
wherein x is from about 20 to about 2,000 and R and R' are each alkyl or aryl groups, especially methyl, ethyl, propyl, butyl and phenyl. The polydimethylsiloxanes (R and R' are methyi) having a molecular weight within the range of from about 200 to about 2,000,000, and higher, are all useful as suds controlling agents. Additional suitable silicone materials wherein the side chain groups R and R' are alkyl, aryl, or mixed alkyl or aryl hydrocarbyl groups exhibit useful suds controlling properties. Examples of the like ingredients include diethyl-, dipropyl-, dibutyl-, methyl-, ethyl-, phenylmethylpoty-siloxanes and the like. Additional useful silicone suds controlling agents can be represented by a mixture of an alkylated siloxane, as referred to hereinbefore, and solid silica. Such mixtures are prepared by affixing the silicone to the surface of the solid silica. A preferred silicone suds controlling agent is represented by a hydrophobic silanated (most preferably trimethylsilanated) silica having a particle size in the range from about 10 millimicrons to 20 millimicrons and a specific surface area above about 50 m2/gm. intimately admixed with dimethyl silicone fluid having a molecular weight in the range from about 500 to about 200,000 at a weight ratio of silicone to silanated silica of from about 19:1 to about 1:2. The silicone suds suppressing agent is advantageously releasably incorporated in a water-soluble or water-dispersible; substantially non-surface-active detergent-impermeable carrier.
[0071] Particularly useful suds suppressors are the self-emulsifying silicone suds suppressors, described in U.S. Patent 4,073,118, Gault et al, issued February 21, 1978, incorporated herein by reference- An example of such a compound is DB-544, commercially available from Dow Corning, which is a siloxane/glycol copolymer.
[0072] Suds modifiers as described above are used at levels of up to approximately 2%, preferably from about 0.1 to about 11 2% by weight of the surfactant
[0073] Microcrystalline waxes having a melting point in the range from 35°C-115°C and a saponification value of less than 100 represent additional examples of preferred suds control components for use in the subject compositions, and are described in detail in U.S. Patent 4,056,481, Tate, issued November 1, 1977, incorporated herein by reference. The microcrystalline waxes are substantially water-insoluble, but are water-dispersible in the presence of organic surfactants. Preferred microcrystalline waxes have a melting point from about 65°C to 100°C, a molecular weight in the range from 400-1,000; and a penetration value of at least 6, measured at 77°F by ASTM-D1321. Suitable examples of the above waxes include: microcrystalline and oxidized microcrystalline petroleum waxes; Fischer-Tropsch and oxidized Fischer-Tropsch waxes; ozokerite; ceresin; montan wax; beeswax; candelilla; and carnauba wax.
[0074] Alkyl phosphate esters represent an additional preferred suds control agent for use herein. These preferred phosphate esters are predominantly monostearyl phosphate which, in addition thereto, can contain di-and tristearyl phosphates and monooleyl phosphate, which can contain di-and trioleyl phosphate.
[0075] Other suds control agents useful in the practice of the invention are the soap or the soap and nonionic mixtures as disclosed in U.S. Patents 2,954,347 and 2,954,348, incorporated herein by reference.
[0076] The level of bleach activator or peroxyacid in these bleaching compositions should be sufficient to provide between from about 0.2 to about 10 mg L-' active oxygen, preferably from about 0.5 to about 4 mg L-' of active oxygen, and most preferably about 2 mg L-' of active oxygen.
[0077] This invention also relates to the process of bleaching textiles with a compound which, when in aqueous solution, yields a peroxyacid of the following formula
wherein R is an alkyl chain with from about 10 to about 15 carbon atoms, preferably 11 carbon atoms.
[0078] The following examples are given to illustrate the parameters of and compositions within the invention. All percentages, parts and ratios are by weight unless otherwise indicated.
Comparative Example 1
[0079] The following data show the results of a bleach test using a detergent outside the scope of the current invention. For comparison, the efficacy of each bleach treatment in removing the specified stain is expressed as a percentage of the removal achieved by a reference bleach, C.OBS, wherein C. denotes the carbon chain length including carbonyl carbon and OBS denotes the oxybenzenesulfonate leaving group. The activators perhydrolyze to generate the corresponding monoperoxy acid, for example, C.MPA. In several of the examples shown, the monoperoxy acid is delivered to the wash medium directly.
[0081] The detergent formula used for these tests delivered the following concentrations of actives:
Test pH was 10.0 and temperature was 95°F. Perborate was notincluded when the peroxyacids were used directly.
[0082] This test shows that the C12OBS activator performs poorly in the presence of a cationic surfactant, even though the corresponding monoperoxy acid (C12MPA) performs well. The test also shows that C14 MPA performs poorly.
Example 1
[0083] The extent of perhydrolysis of any bleach activator is an important indicator of its potential bleaching performance level. Perhydrolysis may be measured by dissolving the activator and hydrogen peroxide together in water at constant pH and temperature. Aliquots are then sampled from the reaction medium and mixed with an ice cold aqueous solution of potassium iodide and glacial acetic acid. The resulting brown color is titrated to a colorless endpoint with sodium thiosuffate solution. The volume of titrant employed is related to the amount of activator that has been converted into the desired peroxy acid.
[0084] The following table shows data developed for the activator, C12OBS, with a five mole excess of hydrogen peroxide.
[0086] The bleach activator, C12OBS, was used at 0.30m M and hydrogen peroxide at 1.5m M . The reactions were carried out at 38°C and pH 10. The data were obtained after 3-5 min. of reaction time.
[0087] The results again show that no peroxy acid is produced in the presence of a cationic surfactant The data also show that increasing ionic strength decreases the amount of peroxy acid generated.
Example 11
[0088] The following table compares the performance of C12 OBS and C9 OBS in a stain removal test in a detergent formula having an ionic strength of 0.010 and a pH of 10.3.
[0089] A panel score unit represents the averages of grades given by three expert panelists using the scale: 0 = no difference; 1 = think there's a small difference; 2 = know there's a small difference; 3 = know there's a large difference. The results above show that C12OBS plus a fivefold molar excess of hydrogen peroxide deliver stain removal performance equal to if not better than that of C9OBS. In an analogous experiment in which a cationic surfactant was present, this comparison heavily favored C9OBS, as in comparative Example I.
[0091] The test was carried out in 1-L of water at 100°F in a Terg-O-Tometer pot with 100 rpm agitation. The conversion of C12OBS to C12MPA was 51%.
Example III
[0092] The following table compares the performance of C12 MPA in a stain removal test in detergent formulae having varying ionic strengths and a pH of 10.0.
[0094] The test was carried out as described in Example 11. 30 Example IV The results show that the performance of C12 MPA declines
[0095] above an ionic strength of 0.050 except on spaghetti stain The following table compares the performance of C,4 which is susceptible to bleaching by the lauroyl peroxide MPA across several ionic strengths using the methodology formed under these conditions. described in Example (111. 35
1. A bleaching composition comprising a compound which provides in an aqueous solution
a compound of the formula
wherein R is an alkyl group containing from about 10 to about 15 carbon atoms, in which the ionic strength of the bleaching composition is no more than 0.05M, and the solution is substantially free of cationic surfactants.
wherein R is an alkyl group containing from about 10 to about 15 carbon atoms, in which the ionic strength of the bleaching composition is no more than 0.05M, and the solution is substantially free of cationic surfactants.
2. A composition according to Claim 1 wherein the compound has the formula
wherein R is an alkyl group containing from about 10 to about 15 carbon atoms.
wherein R is an alkyl group containing from about 10 to about 15 carbon atoms.
3. A composition according to Claim 1 wherein R is an alkyl group containing about
11 carbon atoms.
4. A composition according to Claim 1 wherein the compound is a magnesium peroxycarboxylate
of the following general formula
wherein R is as defined in Claim 1, X is a compatible anion, and n is 1 or 2, and Y is from about 0 to about 6.
wherein R is as defined in Claim 1, X is a compatible anion, and n is 1 or 2, and Y is from about 0 to about 6.
5. A composition according to Claim 4 wherein R is an alkyl group containing about
11 carbon atoms.
6. A composition according to Claim 1 wherein the compound is a bleach activator of
the general formula
wherein R is as defined in Claim 1, wherein L is a leaving group.
wherein R is as defined in Claim 1, wherein L is a leaving group.
7. A composition according to Claim 6 wherein R is an alkyl group containing about
11 carbon atoms.
8. The composition of Claim 6 wherein L is a leaving group, the conjugate acid of
which has a pKa in the range of from about 4 to about 13.
9. The composition of Claim 8 wherein L is a leaving group, the conjugate acid of
which has a pKa in the range of from about 8 to about 11.
10. The composition of Claim 6 wherein L is selected from the group consisting of:
wherein R is as defined in Claim 1, R2 is an alkyl chain containing from about 1 to about 8 carbon atoms, R3 is H or R2, and Y is H or a solubilizing group.
wherein R is as defined in Claim 1, R2 is an alkyl chain containing from about 1 to about 8 carbon atoms, R3 is H or R2, and Y is H or a solubilizing group.
11. The composition of Claim 10 wherein Y is selected from the group consisting of:
-SO-3 M*, -COO-M+,-SO-4 M+, (-N+R34)X-and O ← NR2 and mixtures thereof wherein R4 is an alkyl chain containing from about 1 to about 4 carbon atoms, M is a cation
which provides solubility to the bleach activator and X is an anion which provides
solubility to the bleach activator.
12. The composition of Claim 11 wherein Y is selected from the group consisting of
-SO3-M+, -COO-M+ and mixtures thereof wherein M is selected from the group consisting of sodium, potassium
and mixtures thereof.
13. The composition of Claim 10 wherein L is selected from the group consisting of:
and
wherein R2 is an alkyl chain containing from about 1 to about 8 carbon atoms, Y is -SO3-M+ or -COO-M+ wherein M is sodium or potassium.
and
wherein R2 is an alkyl chain containing from about 1 to about 8 carbon atoms, Y is -SO3-M+ or -COO-M+ wherein M is sodium or potassium.
14. The composition of Claim 13 wherein L has the general formula:
or
wherein M is sodium or potassium.
or
wherein M is sodium or potassium.
15. A bleaching composition according to any of Claims 1 to 14 additionally comprising from about 1% to about 30% of an organic surfactant
16. A composition according to Claim 15 comprising:
(a) a peroxygen bleaching compound capable of yielding hydrogen peroxide in an aqueous solution;
(b) a bleach activator having the general formula:
wherein R is an alkyl group containing from about 10 to about 15 carbon atoms wherein
the molar ratio of hydrogen peroxide yielded by (a) to bleach activator (b) is greater
than about 1; and
(c) from about 1 % to about 20% of an anionic surfactant.