Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/0005—Other compounding ingredients characterised by their effect
  • C11D3/0084—Antioxidants; Free-radical scavengers
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3902—Organic or inorganic per-compounds combined with specific additives
  • C11D3/3937—Stabilising agents
  • C11D3/394—Organic compounds
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3947—Liquid compositions

Definitions

• This invention relates to household fabric bleaching compositions, more particular liquid peroxide, e.g., hydrogen peroxide based bleaching compositions including additional adjuncts such as surface active agents, fluorescent whiteners and dyes.
• the bleaching compositions have the peroxide and certain adjuncts therein stabilized by the addition of agents to chelate heavy metal cations and scavenge free radicals.
• Liquid bleaches have long been used in households as aids in the bleaching and cleaning of fabrics. Hypochlorite bleaches have been used most extensively for this purpose since they are highly effective, inexpensive and simple to produce.
• Liquid bleaching compositions including peroxy compounds have generally been utilized less in the household market than the solid forms referred to above. Although hydrogen peroxide compositions effectively bleach a broad range of fabric materials, are less harsh than hypochlorite bleaches and do not release objectional gases or odors, they have not found as much use in the household market as hypochlorite bleaches. This lack of use in the household market has been partially attributable to the instability of peroxide solutions. Instability is mediated principally by metal ion contamination even in extremely low concentrations. Considerable effort has been expended in the search for stabilizing agents for hydrogen peroxide compositions.
• pre-spotter compositions most advantageously include surfactants for their detergent effect, fluorescent whiteners (also known as optical brighteners) to increase fabric reflectance and the user's perception of increased whiteness, and dyes for producing a pleasing color to the bleach solutions. All of the above components, in addition to the bleach compounds themselves, have been found to be necessary in a liquid peroxygen bleaching composition to achieve full acceptance in the household market.
• liquid bleaching compositions based upon peroxide not only deteriorate from the presence of contaminants, e.g., trace metal cations (0.5ppm or greater); in addition, the surfactant, fluorescent whiteners and dyes are attacked by the peroxide itself, as it is a powerful oxidizing agent.
• peroxide based bleaching compositions including surfactants, fluorescent whiteners and dyes deteriorate quite rapidly.
• the surfactants are oxidized and lose their detergency; the fluorescent whiteners are oxidized and lose their effect; and the dyes are oxidized and lose their color or are changed to undesirable colors.
• the present invention is directed to methods for stabilizing liquid hydrogen peroxide based compositions, and more especially to stabilizing liquid peroxide bleaching compositions that also include surfactants, fluorescent whiteners and dyes.
• the invention is also directed to compositions produced by such methods.
• the present invention relates to liquid hydrogen proxide bleaching compositions (including the aforementioned additional components) that are stabilized by the addition thereto of a metal chelating agent as well as a free radical scavenging agent.
• a metal chelating agent as well as a free radical scavenging agent.
• the presence of both the chelating agent and free radical scavenging agent are necessary to achieve the desired stability.
• the metal chelating or sequestering agent may be selected from among known metal chelating agents.
• a preferred group of such chelating agents are the amino­polyphosphonates which are known to sequester metal ions such as Fe+++ and Cu++, as set forth in the parent referred to above.
• the free radical scavenging agent may be selected from organic antioxidants, especially the substituted mono- and di-hydroxybenzenes and their analogs, also as set forth in the parent referred to above.
• Stabilization of hydrogen peroxide compositions including the associated fluorescent whiteners (also known as optical brighteners), surfactant and dye components relies upon the presence of both the metal and chelating agent and the free radical scavenging agent.
• the stabilizing agents need only be present in very small amounts, e.g., tenths to hundredths of a percent by weight of the liquid composition, in order to effectively prevent deterioration and retention of the desired strengths of the various components over extended periods of time.
• stabilization refers to the retention of physical and chemical properties at or somewhat below their initial levels by each of the liquid bleach composition components for extended periods of time; a significant reduction in the rate of deterioration of such components in comparison to unstabilized formulations.
• the peroxide component retains most of its initial oxidation potential
• the surfactant component retains most of its detergency
• the fluorescent whitener retains most of its ability to impart improved appearance to fabrics
• the dye component is prevented from completely oxidizing.
• the parent referred to above provided a method for stabilizing components in a liquid peroxide bleaching composition, including a peroxide oxidant, a surfactant, a fluorescent whitener and a dye by including therein small amounts of a metal chelating or sequestering agent, such as an aminopolyphosphonate, and a free radical scavenging agent, such as a substituted hydroxybenzene.
• a metal chelating or sequestering agent such as an aminopolyphosphonate
• a free radical scavenging agent such as a substituted hydroxybenzene.
• an effective stabilizing system for a liquid peroxide bleaching composition may also include a metal chelating or sequestering agent, such as an amino­polyphosphonate, and an aromatic amine free radical scavenging agent.
• a metal chelating or sequestering agent such as an amino­polyphosphonate, and an aromatic amine free radical scavenging agent.
• a stabilizing system and method for stabilizing a liquid peroxide bleaching composition by incorporating therein a stabilizing system comprising stabilizing effective amounts of a chelating or sequestering agent and an aromatic amine free radical scavenging agent.
• the aromatic amine free radical scavenging agent is preferably selected as having (1) a hydrogen atom attached to the nitrogen in the amine substituent and available for attack by a free radical, and (2) an aromatic ring attached to the same nitrogen for stabilizing the radical formed on the nitrogen by removal of a proton.
• An example of the reaction sequence between an aromatic amine free radical scavenging agent and a free radical, for example in a peroxide containing composition or bleach, is described in greater detail below.
• the aromatic amine free radical scavenging agent is more preferably a primary or secondary aromatic amine in order to have at least one hydrogen atom available on the nitrogen of the amine substituent.
• Commercially available amine antioxidants are generally secondary aryl amines as also described in greater detail below.
• aromatic amine free radical scavenging agent contemplated by the present invention may also be a fused ring amine of a type described in greater detail below.
• One or more hydrogens on an aromatic ring or rings in the aromatic amine free radical scavenging agent can be substituted by a functional group, preferably a hydroxyl group tending to act as an antioxidant itself for achieving increased antioxidizing power in the aromatic amine free radical scavenging agent. Substitution can also be accomplished by means of another aryl ring or an alkyl group containing one or more carbon atoms in order to achieve additional advantages as also described in greater detail below.
• an alkyl group may also be provided for one of two hydrogens attached to a nitrogen in an amine substituent of primary aromatic amine.
• the alkyl group could be substituted for hydrogen atoms in two different primary aromatic amine free radical scavenging agents as also described in greater detail below.
• Liquid hydrogen peroxide based household bleaching compositions are stabilized by the addition of small amounts of a two component system, i.e., a metal chelating or sequestering agent and a free radical scavenging agent.
• the liquid bleach compositions comprise a hydrogen peroxide bleaching component, with the addition of at least one surfactant, fluorescent whiteners, dye, a fragrance if desired, and suitable amounts of an acid or base to maintain the final solution pH in the range of 1-8, more preferably about 1-6, and most preferably about 2-4. Small amounts of the stabilizing agents and, of course, water complete the bleach compositions.
• the peroxide component may be fairly dilute.
• hydrogen peroxide is present at about 3.5% by weight.
• the surfactant is present at levels of about 3-4% by weight.
• the whiteners are present at levels of about 0.15-0.6% by weight.
• the dye may comprise about 0.0002-0.001% by weight of the composition. Small amounts of fragrance oil e.g., about 0.005-0.1% by weight may also be present.
• the stabilizing agents may comprise about 0.05-­0.2% by weight in the case of the chelating agent, and about 0.005-0.05% by weight in the case of the free radical scavenging agent.
• Sufficient pH adjusting agent is added to maintain the product pH at about 1-6, preferably about 2-4.
• Water usually comprises the remaining percentage of the solution and should be deionized to reduce metal ion contaminants to as low a level as possible. It should be noted, however, that even if metal ion contamination reaches levels of 2-10 ppm or more, the stabilizing system of the invention is still effective.
• the stabilizing agents appear to have a synergistic effect upon the stability of the bleach compositions.
• Both the chelating agent and the aromatic amine free radical scavenger of the invention must be present in order to fully stabilize the compositions.
• free radical reactions can be initiated with peroxides which act to abstract a hydrogen ion from, for instance, one of the ethylene groups present on the nonionic surfactant molecules.
• peroxides which act to abstract a hydrogen ion from, for instance, one of the ethylene groups present on the nonionic surfactant molecules.
• the hydrogen peroxide itself may form free radicals by homolytic cleavage of either an O-H bond or the O-O bond. That is: HO : OH -------> ⁇ H + ⁇ OOH , or HO : OH -------> 2 ⁇ OH
• any such free radicals are free to combine with other organic species in the solution, e.g., the optical brighteners and dye.
• Such free radicals would be especially reactive with compounds having conjugated double bonds, e.g., dyes and brighteners.
• the chelating agent appears to act to sequester the heavy metal cations, especially polyvalent metals such as copper and iron, which are always present in small amounts among the mineral components in water.
• the heavy metal cations' ability to catalyse peroxide homolysis is interfered with.
• the heavy metals' ability to mediate free radical generation is eliminated or greatly reduced.
• the free radical scavenging agent appears to work by tying up any free radicals initially formed in the solution.
• the ability of the free radicals to degrade the organic components is removed at the same time the self-­propagating free radical cascade reactions are stopped short.
• destruction of the desired surfactant, optical whitener, dye, and perfume components is arrested or greatly reduced.
• a peroxide source is present as the principal active ingredient and functions as the bleaching agent.
• the peroxide is normally present as hydrogen peroxide and is present in the range of about 0.05-50 weight %, more preferably about 0.1-35 wt.%, and most preferably about 0.5-15 wt.%.
• Hydrogen peroxide is a staple article of commerce available from a number of commercial sources. In making up the bleaching compositions, the peroxide is ordinarily purchased as a concentrated aqueous solution, e.g., 70%, and diluted with deionized water to the desired strength.
• the FMC Corp. of Philadelphia, Pennsylvania is one source of hydrogen peroxide.
• Surfactants are desirable for use in the bleaching compositions. Not only do they perform the normal soil removing function; but, in the present formulations, they also assist in emulsifying the free radical scavenger into the aqueous bleach formulation. As will be noted hereinafter, the free radical scavenger component is somewhat hydrophobic. The surfactants therefore assist mixing of free radical scavenger into the bleach compositions.
• the surfactant component can provide a thickening effect, especially when used in higher concentrations such as when exceeding about 5 wt.%.
• the most preferred surfactants are nonionics. Suitable nonionics include polyethoxylated alcohols, ethoxylated alky phenols, polyoxyethylene or polyoxypropylene block co-polymers, anhydrosorbitol esters, alkoxylated anhydrosorbitol esters, and the like. Other potentially suitable surfactants are disclosed in the Kirk-Othmer Encyclopedia of Chemical Technology , 3rd Edition, Volume 22, pp. 360-377 (1983), the disclosure of which is incorporated herein by reference. Such nonionic surfactants may be obtained from any number of commercial sources. One such source for polyethoxylated alcohols is the Shell Chemical Co. of Houston, Texas and are known under the tradename "Neodol".
• One suitable surfactant is "Neodol 25-7", an ethoxylated alcohol wherein the alcohol has from 12-15 carbons to which 7 ethoxy groups are attached.
• Anhydrosorbitol esters (including sorbitan esters) are available from Atlas Chemical Industries under the tradenames “Tween” and “Arlacel”.
• the surfactant may be present in the compositions in about 3-4 weight %, although this level is not critical. Lower or higher surfactant concentrations are acceptable within the ranges noted.
• the preferred range for surfactant is 0-50 wt.%; the more preferred range is 0-20 wt.%; and the most preferred range is 0-10 wt.%.
• the surfactants may beneficially have a thickening effect on the liquid compositions. Such thickening may aid in the dispersion of particulate components such as dyes and whiteners.
• the surfactants may also assist in emulsifying the liquid compositions and aid in the suspension of some of the free radical scavengers since they tend to be somewhat insoluble in aqueous medium. Mixtures of the surfactants are also suitable.
• Fluorescent whiteners are also included in the bleaching formulations. Such whiteners are also common commercial products. Such products are fluorescent materials, very often substituted stilbenes and biphenyls, having the ability to fluoresce by absorbing ultraviolet wavelengths of light and then emitting visible light, generally in the blue wavelength ranges. The whiteners settle out or deposit onto the fabrics during the bleaching or washing process to impart the desired whiteness.
• the whiteners may be present in the bleaching compositions in the order of several hundredths to about 5 wt.%, more preferably about 0-1 wt.%, and most preferably about 0-0.6 wt.%.
• whiteners may be combined in the compositions. Such selection is governed by the fact that certain whiteners have affinity for cellulose fibers, e.g., cotton while others have affinity for synthetic fibers, e.g., nylon. Since the bleaching compositions of the invention are intended for all types of fabrics, both natural and synthetic, it is advantageous to include whiteners of both types.
• One stilbene based product, “Tinopal RBS” has affinity for synthetic fibers.
• a distyrylbiphenyl product "Tinopal CBS-X” has affinity for cellulose fibers.
• small amounts of dye are also included in the preferred bleaching compositions. While the dye is only a very small percentage (perhaps 0.0005 wt.%) of the compositions, it plays an important part in the consumer's acceptance of the product. It is preferred that such dye be present in the range of about 0-1 wt.%, more preferably about 0-0.1 wt.%, and most preferably about 0-0.001 wt.%. Dyes such as the anthraquinones are particularly suitable. Such anthraquinone dyes are available from the Sandoz Co. of Charlotte, North Carolina. One suitable dye is "Nylosan ZAL" from the aforementioned company. Other dyes of the desired color with resistance to bleaching can also be used. In some instances, inorganic pigments may be used. Preferred pigments are those which have the metallic cations substantially or completely complexed, e.g., copper phthalocyanines.
• a fragrance may also be used in the bleaching formulations, if desired. Any fragrance oil may be used, ordinarily in small quantities, e.g., 0.01%, so long as it is as stable as the other components.
• the preferred range is about 0-5 wt.%. The more preferred range is about 0-1 wt.%; while the most preferred range is about 0-0.1 wt.%.
• a pH adjusting agent is added to the composition in order to adjust the final pH into the 1-8 range, more preferably about 1-6, and most preferably about 2-4.
• Phosphoric and sulfuric acid are preferred for this purpose when acidic pH is desired.
• Other mineral acids such as nitric acid could also be used as well as organic water soluble acids such as acetic acid, citric acid, etc. and hydrochloric acid.
• appropriate amounts of a base could be used if necessary or desirable to raise the pH of the composition.
• the stabilizing system is vital to the bleaching compositions. Both the chelating agent and the free radical scavenger must be present. Tests have shown that neither agent is as effective individually as when present in combination. Synergistic forces are obviously involved in the stabilization and prolonged stability of the bleaching compositions results only when both agents are present.
• the chelating agent may be selected from any number of known agents with the caveat that any agent selected must be effective in chelating heavy metal cations, such as Cu++ and Fe+++.
• the chelating agent should also be resistant to hydrolysis; and not easily oxidized by hydrogen peroxide. Perferably, it should have an acid dissociation constant, i.e., pKa of about 1-9, indicating that it dissociates at low pH levels to permit bonding to the metal cations.
• amino polyphosphonates have been found to be most useful in the present bleaching compositions.
• the amino polyphosphonates are commercially available compounds sold, for example, under the trademark "Dequest” by the Monsanto Co. of St. Louis, Missouri. These compounds have structures such as:
• Such "Dequest” compounds are extremely effective as chelating agents in the bleach compositions.
• Other related chelating agents such as the pyrophosphates may also be utilized.
• the selected chelating agent should be present in the compositions in an amount sufficient to thoroughly tie up any heavy metal cations present in the aqueous solution. One or two tenths of a percent is sufficient.
• the chelating agent may be present in the range of about 0.02-5 wt.%. A more preferred range is about 0.04-0.3 wt.%. The most preferred range is about 0.06-0.12 wt.%.
• the second vital stabilizing agent is the aromatic amine free radical scavenger referred to above.
• the aromatic amine free radical scavenging agent is characterized by two key features. Initially, at least one hydrogen atom is attached to the nitrogen in the amine substituent of the aromatic amine to be available for attack by a free radical. Secondly, an aromatic ring is attached to the same nitrogen in order to stabilize a radical formed on the nitrogen by removal of a proton resulting from the free radical attack.
• An example of the reaction sequence between an aromatic amine, as contemplated by the present invention, and a free radical is illustrated below:
• the aromatic amine is preferably a primary or secondary amine.
• a number of commercially available substituted secondary aryl amines are illustrated in Table I below.
• One or more hydrogens on an aromatic ring or rings in the aromatic amine free radical scavenging agent may be substituted by a functional group, preferably a hydroxyl group acting as an antioxidant itself for increased antioxidizing power in the aromatic amine. Substitution may also involve another aryl ring or an alkyl group containing one or more carbon atoms. For example, a number of substituted diaryl amines are included in Table I below.
• substitution preferably by an alkyl group, may also take place for a hydrogen atom on the nitrogen of an amine substituent in a primary aromatic amine (in order to retain at least one hydrogen atom on the nitrogen in accordance with the requirements set forth above).
• substitution by an alkyl group could also occur for hydrogen atoms on two different primary aryl amines to result in a product having the structure set forth below:
• the aromatic amine of the present invention could comprise a fused ring structure resulting in a product such as a naphthyl amine.
• Other fused ring aromatic amines in accordance with the present invention could include anthracene and phenanthrene, for example.
• the free radical scavenging agent must generally resist oxidation by a peroxide such as hydrogen peroxide and, therefore, cannot be an overly strong reducing agent which would more likely react with the peroxide itself.
• the free radical scavenger Only very small amounts of the free radical scavenger are necessary in the bleach compositions. Generally, one to several hundredths of a percent provides effective free radical scavenging. The preferred range is about 0.005-0.1 wt.%. A more preferred range is about 0.007-0.04 wt.%; however, the most preferred range is about 0.01-0.02 wt.%.
• a typical stabilized bleach formulation is set forth below: PREFERRED STABILIZED BLEACHING FORMULATIONS Component Wt. % Nonionic surfactant (Neodol) 2-4 Fluorescent whitener - distyrylbiphenyl 0.1-0.7 - stilbene 0.01-0.3 Blue dye - anthroquinone 0.0002-0.001 Fragrance 0.01-0.05 H2O2 3-7 Aminopolyhosphonate chelating agent 0.06-0.25 Free radical scavenger 0.005-0.02 Phosphoric acid sufficient to adjust pH to 2.3 H2O - deionized remainder
• a number of more specific examples of stabilized bleaching systems made and tested according to the present invention each have the formulation set forth immediately below (Formulation A) with respective stabilizing systems indicated in Table II.
• FORMULATION A Ingredient Wt.% H2O2 3.5 Brightener1 0.16 Dye2 0.0005 Surfactant3 3.5 Fragrance 0.01 Free Radical Scavenger4 0.01 Chelating Agent5 0.12 pH Adjusting Agent (H3PO4) 0.1 Water Balance 1Fluorescent Whitening Agent, a distyryl biphenyl compound, e.g., Tinopal CBS-X, from Ciba - Geigy, Inc. 2Anthraquinone dye, Acid Blue 25, from Sandoz Company. 3Surfactant was Neodol 25-7, a C12 ⁇ 15 linear ethoxylated alcohol with about 7 moles of ethylene oxide per mole or alcohol. 4See below. 5See below.
• the samples were initially measured for available oxygen (via Iodometric titration) and amounts of dye (without dilution) and brightener (dilution factor: 3 mls. formulation/1,000 mls. water). Amounts of dye and brightener were measured as absorbance units via a Beckman Spectrophotometer set at wavelengths 598 nm and 344 nm, respectively.
• Example 1 which used neither chelating agent nor free radical scavenger, had no stabilizing effect on dyes or brighteners.
• Examples 2-4 containing only metal chelating agents, have no stabilizing effect on dyes and minimal to no effect on brighteners.
• Examples 5-7 containing only aromatic amine free radical scavengers, have no stabilizing effect on dyes and minimal to no effect on brighteners.
• Examples 8-10 on the other hand, in which both metal chelating agent and aromatic amine free radical scavenger, show dramatic improvement in stability. Occasionally, some Examples (9, 12, 14-16) show lack of stabilizing effect on dyes, but overall, increased stability above and beyond that of any Examples 1, 2-4 and 5-7, is demonstrated. The data therefore demonstrates synergistic action of the free radical scavenger and the metal chelating agent to stabilize dyes and brighteners in a very hostile environment - high temperature (boiling point of water) and large concentration of heavy metals.
• aromatic amines in addition to those included in Examples 5-16, may also be employed according to the present invention to achieve similar synergistic results.
• aromatic amines could include all variations defined in TABLE I and summarized elsewhere above.
• FORMULATION B Component: Wt. % Hydrogen Peroxide 4.0 Whitener (Distyrylbiphenyl) 0.3 Acid Blue Dye 0.001 Surfactant (Triton X-100) 4.0 Chelating Agent (Aminopolyphosphonate) 0.18 pH Adjustment (Sulfuric Acid) 0.035 Free Radical Scavenging Agent 0.01 Water Balance FORMULATION C Component: Wt.
• Phorwite CNA may be characterized as: 4,4′ bis(4-phenyl-2H-1,2,3-trazol-2-yl)-2,2′stilbenedisulfonic acid.

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• 1989
  • 1989-06-14 EP EP89306007A patent/EP0349153A3/fr not_active Withdrawn
  • 1989-06-21 JP JP15690589A patent/JPH0245600A/ja active Pending
  • 1989-06-27 AU AU37104/89A patent/AU3710489A/en not_active Abandoned
  • 1989-06-28 MX MX1663789A patent/MX174330B/es unknown
• 1992
  • 1992-09-03 AU AU22132/92A patent/AU2213292A/en not_active Abandoned

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