Disclosed herein is a composition comprising:

1. Field of the Invention
This invention is related to lubricants, especially lubricating oils, and, more particularly, to a class of ashless and non-phosphorus-containing anti-wear, anti-fatigue, and extreme pressure additives derived from 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazoles.
2. Description of Related Art
In developing lubricating oils, there have been many attempts to provide additives that impart antifatigue, antiwear, and extreme pressure properties thereto. Zinc dialkyldithiophosphates (ZDDP) have been used in formulated oils as antiwear additives for more than 50 years. However, zinc dialkyldithiophosphates give rise to ash, which contributes to particulate matter in automotive exhaust emissions, and regulatory agencies are seeking to reduce emissions of zinc into the environment. In addition, phosphorus, also a component of ZDDP, is suspected of limiting the service life of the catalytic converters that are used on cars to reduce pollution. It is important to limit the particulate matter and pollution formed during engine use for toxicological and environmental reasons, but it is also important to maintain undiminished the antiwear properties of the lubricating oil.
In view of the aforementioned shortcomings of the known zinc and phosphorus-containing additives, efforts have been made to provide lubricating oil additives that contain neither zinc nor phosphorus or, at least, contain them in substantially reduced amounts.
Illustrative of non-zinc, i.e., ashless, non-phosphorus-containing lubricating oil additives are the reaction products of 2,5-dimercapto-1,3,4-thiadiazoles and unsaturated mono-, di-, and tri-glycerides disclosed in U.S. Pat. No. 5,512,190 and the dialkyl dithiocarbamate-derived organic ethers of U.S. Pat. No. 5,514,189.
U.S. Pat. No. 5,512,190 discloses an additive that provides antiwear properties to a lubricating oil. The additive is the reaction product of 2,5-dimercapto-1,3,4-thiadiazole and a mixture of unsaturated mono-, di-, and triglycerides. Also disclosed is a lubricating oil additive with antiwear properties produced by reacting a mixture of unsaturated mono-, di-, and triglycerides with diethanolamine to provide an intermediate reaction product and reacting the intermediate reaction product with 2,5-dimercapto-1,3,4 thiadiazole.
U.S. Pat. No. 5,514,189 discloses that dialkyl dithiocarbamate-derived organic ethers have been found to be effective antiwear/antioxidant additives for lubricants and fuels.
U.S. Pat. Nos. 5,084,195 and 5,300,243 disclose N-acyl-thiourethane thioureas as antiwear additives specified for lubricants or hydraulic fluids.
The disclosures of the foregoing references are incorporated herein by reference in their entirety.
The present invention relates to compounds of the formula
wherein R1 is a hydrocarbon or functionalized hydrocarbon of from 1 to 30 carbon atoms.
In the above structural formulas, R1 can be a straight or branched chain, fully saturated or partially unsaturated, hydrocarbon moiety, preferably alkyl or alkenyl having from 1 to 30 carbon atoms, e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, oleyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, triacontyl, ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, oleenyl, nonadecenyl, eicosenyl, heneicosenyl, docosenyl, tricosenyl, tetracosenyl, pentacosenyl, triacontenyl, and the like, and isomers and mixtures thereof Additionally, R1 can be a straight or branched chain, a fully saturated or partially unsaturated hydrocarbon chain, preferably having from 1 to 30 carbon atoms, within which may be ester groups or heteroatoms, such as, oxygen, sulfur, and nitrogen, which may take the form of ethers, polyethers, sulfides, amines, and amides. This is what is meant by xe2x80x9cfunctionalized hydrocarbon.xe2x80x9d
The 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compounds of this invention are useful as ashless, non-phosphorus-containing antifatigue, antiwear, extreme pressure additives for lubricating oils.
The present invention also relates to lubricating oil compositions comprising a lubricating oil and a functional property-improving amount of at least one 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compound of the above formulas. More particularly, the present invention is directed to a composition comprising:
(A) a lubricant, and
(B) at least one 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compound of the formula:
xe2x80x83wherein R1 is a hydrocarbon or functionalized hydrocarbon of from 1 to 30 carbon atoms.
It is preferred that the 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole is present in the compositions of the present invention in a concentration in the range of from about 0.01 to about 10 wt %.
The 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compounds of the present invention are compounds of the formula:
wherein R1 is a hydrocarbon or functionalized hydrocarbon of from 1 to 30 carbon atoms.
In the above structural formula, R1 is preferably an alkyl moiety of 1 to 30 carbon atoms, more preferably of 1 to 22 carbon atoms, most preferably of 1 to 10 carbon atoms, and can have either a straight chain or a branched chain, a fully saturated or partially unsaturated hydrocarbon chain, alkylaryl, e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, oleyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, triacontyl, dodecyl phenyl, octyl phenyl, and the like, and isomers, e.g., 1-ethylpentyl, 2-ethylhexyl, and mixtures thereof. Where R1 is alkyl, it can be either a straight or a branched hydrocarbon chain, a fully saturated or partially unsaturated hydrocarbon chain, wherein said chains may contain ester groups or heteroatoms, such as oxygen and/or sulfur and/or nitrogen, which may take the form of ethers, polyethers, sulfides, amines, amides, and the like. As employed herein, the term xe2x80x9calkylxe2x80x9d is also intended to include xe2x80x9ccycloalkyl.xe2x80x9d Where the alkyl is cyclic, it preferably contains from 3 to 9 carbon atoms, e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and the like. Cycloalkyl moieties having 5 or 6 carbon atoms, i.e., cyclopentyl or cyclohexyl, are more preferred.
The use of the 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole compounds of this invention can improve the antifatigue, antiwear, and extreme pressure properties of a lubricant.
The following is a typical preparation of a 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole using oleyl hydrazide as the starting raw material to make 5-heptadecenyl-2-mercapto-1,3,4-oxadiazole.
In a 50 mL flask equipped with a magnetic stirring bar, nitrogen blanket with a caustic trap to absorb evolving hydrogen sulfide gas by-product, reflux condenser, thermocouple, and heating mantle, is charged 5 mL of triethylamine and 2.5 grams of carbon disulfide. To the reaction media, under a nitrogen blanket with stirring, is added dropwise a solution of 7.0 grams of oleyl hydrazide dissolved in 10 mL of warm triethylamine over a 10 minute period. This results in an immediate 20 to 25xc2x0 C. exotherm to 42xc2x0 C. The temperature is slowly raised to 90xc2x0 C. and held for 15 hrs. with the evolution of hydrogen sulfide. The reaction media are then placed under 100 mm Hg vacuum for one hour at 130xc2x0 C. to remove any residual hydrogen sulfide and triethylamine solvent. The final product is an orange liquid at room temperature which slowly solidifies to a paste.
The 5-hydrocarbyl-2-mercapto-1,3,4-oxadiazole additives of this invention can be used as either a partial or complete replacement for the zinc dialkyldithiophosphates currently used. They can also be used in combination with other additives typically found in lubricating oils, as well as with other ashless, antiwear additives. This invention may also display synergistic effects with these other typical additives to improve oil performance properties in lubricating oils. The additives typically found in lubricating oils are, for example, dispersants, detergents, corrosion/rust inhibitors, antioxidants, antiwear agents, antifoamants, friction modifiers, seal swell agents, demulsifiers, VI improvers, pour point depressants, and the like. See, for example, U.S. Pat. No. 5,498,809 for a description of useful lubricating oil composition additives, the disclosure of which is incorporated herein by reference in its entirety. Examples of dispersants include polyisobutylene succinimides, polyisobutylene succinate esters, Mannich Base ashless dispersants, and the like. Examples of detergents include metallic alkyl phenates, metallic sulfurized alkyl phenates, metallic alkyl sulfonates, metallic alkyl salicylates, and the like. Examples of antioxidants include alkylated diphenylamines, N-alkylated phenylenediamines, hindered phenolics, alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylidenebisphenols, oil soluble copper compounds, and the like. Examples of antiwear additives that can be used in combination with the additives of the present invention include organo borates, organo phosphites, organic sulfur-containing compounds, zinc dialkyldithiophosphates, zinc diaryldithiophosphates, phosphosulfurized hydrocarbons, and the like. The following are exemplary of such additives and are commercially available from The Lubrizol Corporation: Lubrizol 677A, Lubrizol 1095, Lubrizol 1097, Lubrizol 1360, Lubrizol 1395, Lubrizol 5139, and Lubrizol 5604, among others. Examples of friction modifiers include fatty acid esters and amides, organo molybdenum compounds, molybdenum dialkylthiocarbamates, molybdenum dialkyl dithiophosphates, and the like. An example of an antifoamant is polysiloxane, and the like. An example of a rust inhibitor is a polyoxyalkylene polyol, and the like. Examples of VI improvers include olefin copolymers and dispersant olefin copolymers, and the like. An example of a pour point depressant is polymethacrylate, and the like.
Representative conventional antiwear agents that can be used include, for example, the zinc dialkyl dithiophosphates and the zinc diaryl dithiophosphates.
Suitable phosphates include dihydrocarbyl dithiophosphates, wherein the hydrocarbyl groups contain an average of at least 3 carbon atoms. Particularly useful are metal salts of at least one dihydrocarbyl dithiophosphoric acid wherein the hydrocarbyl groups contain an average of at least 3 carbon atoms. The acids from which the dihydrocarbyl dithiophosphates can be derived can be illustrated by acids of the formula:
wherein R2 and R3 are the same or different and are alkyl, cycloalkyl, aralkyl, alkaryl or substituted substantially hydrocarbon radical derivatives of any of the above groups, and wherein the R2 and R3 groups in the acid each have, on average, at least 3 carbon atoms. By xe2x80x9csubstantially hydrocarbonxe2x80x9d is meant radicals containing substituent groups (e.g., 1 to 4 substituent groups per radical moiety) such as ether, ester, nitro, or halogen that do not materially affect the hydrocarbon character of the radical.
Specific examples of suitable R2 and R3 radicals include isopropyl, isobutyl, n-butyl, sec-butyl, n-hexyl, heptyl, 2-ethylhexyl, diisobutyl, isooctyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, butylphenyl,o,p-depentylphenyl, octylphenyl, polyisobutene-(molecular weight 350)-substituted phenyl, tetrapropylene-substituted phenyl, beta-octylbutylnaphthyl, cyclopentyl, cyclohexyl, phenyl, chlorophenyl, o-dichlorophenyl, bromophenyl, naphthenyl, 2-methylcyclohexyl, benzyl, chlorobenzyl, chloropentyl, dichlorophenyl, nitrophenyl, dichlorodecyl and xenyl radicals. Alkyl radicals having from about 3 to about 30 carbon atoms and aryl radicals having from about 6 to about 30 carbon atoms are preferred. Particularly preferred R2and R3 radicals are alkyl of from 4 to 18 carbon atoms.
The phosphorodithioic acids are readily obtainable by the reaction of phosphorus pentasulfide and an alcohol or phenol. The reaction involves mixing, at a temperature of about 20xc2x0 C. to 200xc2x0 C., 4 moles of the alcohol or phenol with one mole of phosphorus pentasulfide. Hydrogen sulfide is liberated as the reaction takes place. Mixtures of alcohols, phenols, or both can be employed, e.g., mixtures of C3 to C30 alcohols, C6 to C30 aromatic alcohols, etc.
The metals useful to make the phosphate salts include Group I metals, Group II metals, aluminum, lead, tin, molybdenum, manganese, cobalt, and nickel. Zinc is the preferred metal. Examples of metal compounds that can be reacted with the acid include lithium oxide, lithium hydroxide, lithium carbonate, lithium pentylate, sodium oxide, sodium hydroxide, sodium carbonate, sodium methylate, sodium propylate, sodium phenoxide, potassium oxide, potassium hydroxide, potassium carbonate, potassium methylate, silver oxide, silver carbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium ethylate, magnesium propylate, magnesium phenoxide, calcium oxide, calcium hydroxide, calcium carbonate, calcium methylate, calcium propylate, calcium pentylate, zinc oxide, zinc hydroxide, zinc carbonate, zinc propylate, strontium oxide, strontium hydroxide, cadmium oxide, cadmium hydroxide, cadmium carbonate, cadmium ethylate, barium oxide, barium hydroxide, barium hydrate, barium carbonate, barium ethylate, barium pentylate, aluminum oxide, aluminum propylate, lead oxide, lead hydroxide, lead carbonate, tin oxide, tin butylate, cobalt oxide, cobalt hydroxide, cobalt carbonate, cobalt pentylate, nickel oxide, nickel hydroxide, and nickel carbonate.
In some instances, the incorporation of certain ingredients, particularly carboxylic acids or metal carboxylates, such as, small amounts of the metal acetate or acetic acid, used in conjunction with the metal reactant will facilitate the reaction and result in an improved product. For example, the use of up to about 5% of zinc acetate in combination with the required amount of zinc oxide facilitates the formation of a zinc phosphorodithioate.
The preparation of metal phosphorodithioates is well known in the art and is described in a large number of issued patents, including U.S. Pat. Nos. 3,293,181; 3,397,145; 3,396,109 and 3,442,804, the disclosures of which are hereby incorporated by reference. Also useful as antiwear additives are amine derivatives of dithiophosphoric acid compounds, such as are described in U.S. Pat. No. 3,637,499, the disclosure of which is hereby incorporated by reference in its entirety.
The zinc salts are most commonly used as antiwear additives in lubricating oil in amounts of 0.1 to 10, preferably 0.2 to 2, wt. %, based upon the total weight of the lubricating oil composition. They may be prepared in accordance with known techniques by first forming a dithiophosphoric acid, usually by reaction of an alcohol or a phenol with P2S5 and then neutralizing the dithiophosphoric acid with a suitable zinc compound.
Mixtures of alcohols can be used, including mixtures of primary and secondary alcohols, secondary generally for imparting improved antiwear properties and primary for thermal stability. Mixtures of the two are particularly useful. In general, any basic or neutral zinc compound could be used, but the oxides, hydroxides, and carbonates are most generally employed. Commercial additives frequently contain an excess of zinc owing to use of an excess of the basic zinc compound in the neutralization reaction.
The zinc dihydrocarbyl dithiophosphates (ZDDP) are oil soluble salts of dihydrocarbyl esters of dithiophosphoric acids and can be represented by the following formula:
wherein R2 and R3 are as described in connection with the previous formula.
Especially preferred additives for use in the practice of the present invention include alkylated diphenylamines, hindered alkylated phenols, hindered alkylated phenolic esters, and molybdenum dithiocarbamates.
Compositions, when they contain these additives, are typically blended into the base oil in amounts such that the additives therein are effective to provide their normal attendant functions. Representative effective amounts of such additives are illustrated in TABLE 1.
When other additives are employed, it may be desirable, although not necessary, to prepare additive concentrates comprising concentrated solutions or dispersions of the subject additives of this invention, together with one or more of said other additives (said concentrate when constituting an additive mixture being referred to herein as an additive-package) whereby several additives can be added simultaneously to the base oil to form the lubricating oil composition. Dissolution of the additive concentrate into the lubricating oil can be facilitated by solvents and/or by mixing accompanied by mild heating, but this is not essential. The concentrate or additive-package will typically be formulated to contain the additives in proper amounts to provide the desired concentration in the final formulation when the additive-package is combined with a predetermined amount of base lubricant. Thus, the subject additives of the present invention can be added to small amounts of base oil or other compatible solvents along with other desirable additives to form additive-packages containing active ingredients in collective amounts of, typically, from about 2.5 to about 90 percent, preferably from about 15 to about 75 percent, and more preferably from about 25 percent to about 60 percent by weight additives in the appropriate proportions with the remainder being base oil. The final formulations can typically employ about 1 to 20 weight percent of the additive-package with the remainder being base oil.
All of the weight percentages expressed herein (unless otherwise indicated) are based on the active ingredient (AI) content of the additive, and/or upon the total weight of any additive-package, or formulation, which will be the sum of the AI weight of each additive plus the weight of total oil or diluent.
In general, the lubricant compositions of the invention contain the additives in a concentration ranging from about 0.05 to about 30 weight percent. A concentration range for the additives ranging from about 0.1 to about 10 weight percent based on the total weight of the oil composition is preferred. A more preferred concentration range is from about 0.2 to about 5 weight percent. Oil concentrates of the additives can contain from about 1 to about 75 weight percent of the additive reaction product in a carrier or diluent oil of lubricating oil viscosity.
In general, the additives of the present invention are useful in a variety of lubricating oil base stocks. The lubricating oil base stock is any natural or synthetic lubricating oil base stock fraction having a kinematic viscosity at 100xc2x0 C. of about 2 to about 200 cSt, more preferably about 3 to about 150 cSt, and most preferably about 3 to about 100 cSt. The lubricating oil base stock can be derived from natural lubricating oils, synthetic lubricating oils, or mixtures thereof Suitable lubricating oil base stocks include base stocks obtained by isomerization of synthetic wax and wax, as well as hydrocrackate base stocks produced by hydrocracking (rather than solvent extracting) the aromatic and polar components of the crude. Natural lubricating oils include animal oils, such as, lard oil, vegetable oils (e.g., canola oils, castor oils, sunflower oils), petroleum oils, mineral oils, and oils derived from coal or shale.
Synthetic oils include hydrocarbon oils and halo-substituted hydrocarbon oils, such as, polymerized and interpolymerized olefins, alkylbenzenes, polyphenyls, alkylated diphenyl ethers, alkylated diphenyl sulfides, as well as their derivatives, analogs, homologues, and the like. Synthetic lubricating oils also include alkylene oxide polymers, interpolymers, copolymers, and derivatives thereof, wherein the terminal hydroxyl groups have been modified by esterification, etherification, etc.
Another suitable class of synthetic lubricating oils comprises the esters of dicarboxylic acids with a variety of alcohols. Esters useful as synthetic oils also include those made from C5 to C12monocarboxylic acids and polyols and polyol ethers.
Silicon-based oils (such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils) comprise another useful class of synthetic lubricating oils. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids, polymeric tetrahydrofurans, poly xcex1-olefins, and the like.
The lubricating oil may be derived from unrefined, refined, rerefined oils, or mixtures thereof Unrefined oils are obtained directly from a natural source or synthetic source (e.g., coal, shale, or tar and bitumen) without further purification or treatment. Examples of unrefined oils include a shale oil obtained directly from a retorting operation, a petroleum oil obtained directly from distillation, or an ester oil obtained directly from an esterification process, each of which is then used without further treatment. Refined oils are similar to unrefined oils, except that refined oils have been treated in one or more purification steps to improve one or more properties. Suitable purification techniques include distillation, hydrotreating, dewaxing, solvent extraction, acid or base extraction, filtration, percolation, and the like, all of which are well-known to those skilled in the art. Rerefined oils are obtained by treating refined oils in processes similar to those used to obtain the refined oils. These rerefined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques for removal of spent additives and oil breakdown products.
Lubricating oil base stocks derived from the hydroisomerization of wax may also be used, either alone or in combination with the aforesaid natural and/or synthetic base stocks. Such wax isomerate oil is produced by the hydroisomerization of natural or synthetic waxes or mixtures thereof over a hydroisomerization catalyst. Natural waxes are typically the slack waxes recovered by the solvent dewaxing of mineral oils; synthetic waxes are typically the wax produced by the Fischer-Tropsch process. The resulting isomerate product is typically subjected to solvent dewaxing and fractionation to recover various fractions having a specific viscosity range. Wax isomerate is also characterized by possessing very high viscosity indices, generally having a VI of at least 130, preferably at least 135 or higher and, following dewaxing, a pour point of about xe2x88x9220xc2x0 C. or lower.
The additives of the present invention are especially useful as components in many different lubricating oil compositions. The additives can be included in a variety of oils with lubricating viscosity, including natural and synthetic lubricating oils and mixtures thereof The additives can be included in crankcase lubricating oils for spark-ignited and compression-ignited internal combustion engines. The compositions can also be used in gas engine lubricants, turbine lubricants, automatic transmission fluids, gear lubricants, compressor lubricants, metal-working lubricants, hydraulic fluids, and other lubricating oil and grease compositions. The additives can also be used in motor fuel compositions.
The advantages and the important features of the present invention will be more apparent from the following examples.

Abstract: (A) a lubricant, and


The present invention relates to liquid hypohalite bleach-containing compositions which comprise an alkyl ethoxy sulphate having a low number of moles of ethoxy groups.

The present invention relates to bleaching compositions, in particular to hypochlorite bleaching compositions, suitable for use in various laundry applications including hand and machine laundry methods.
Bleaching compositions are well-known in the art. Amongst the different bleaching compositions available, those relying on bleaching by hypohalite bleaches such as hypochlorite are often preferred, mainly for performance reasons, especially at lower temperature.
However hypohalite bleaches are known to be aggressive bleaching agents that may potentially facilitate the decomposition of other components of a bleaching composition. The Applicant has found that this is particularly true of alkyl ethoxy sulphates which are often preferred anionic surfactants of hypohalite bleach-containing compositions.
EP 243 685 and EP 181 212 both describe compositions comprising alkyl ethoxy sulphate having an average of from 1 to 3 and less than 6 moles of ethoxy groups respectively. However neither document describe compositions comprising hypohalite bleach.
EP 580 245 describes a composition comprising alky ethoxy sulphate having from 1 to 11 moles of ethoxy groups and optionally on oxygen-releasing bleach.
Hence, the object of the present invention is to provide a hypohalite-containing composition comprising an alkyl ethoxy sulphate that is stable and provides improved soil removal benefits.
The present invention provides a liquid bleaching composition comprising a hypohalite bleach and an alkyl ethoxy sulphate having an average of 2 or less moles of ethoxy groups.
In another aspect of the present invention there is provided the use of said composition to provide improved stain removal and/or fabric whiteness and storage stability.
Liquid Bleaching Compositions
The compositions according to the present invention are in liquid form. Preferably, the compositions of the invention are in liquid aqueous form. More preferably, they comprise water in an amount of from 60% to 98% by weight, more preferably of from 80% to 97% and most preferably of from 85% to 97% by weight of the total aqueous liquid bleaching composition.
Hypohalite Bleach
An essential component of the invention is a hypohalite bleach. Hypohalite bleaches may be provided by a variety of sources, including bleaches that are oxidative bleaches and subsequently lead to the formation of positive halide ions as well as bleaches that are organic based sources of halides such as chloroisocyanurates.
Suitable hypohalite bleaches for use herein include the alkali metal and alkaline earth metal hypochlorites, hypobromites, hypoiodites, chlorinated trisodium phosphate dodecahydrates, potassium and sodium dichloroisocyanurates, potassium and sodium trichlorocyanurates, N-chloroimides, N-chloroamides, N-chloroamines and chlorohydantoins.
The preferred hypohalite bleaches among the above described, are the alkali metal and/or alkaline earth metal hypochlorites selected from the group consisting of sodium, potassium, magnesium, lithium and calcium hypochlorites, and mixtures thereof, more preferably alkali metal sodium hypochlorite.
Preferably, the liquid compositions according to the present invention comprise said hypohalite bleach such that the content of active halide in the composition is from 0.1% to 20% by weight, more preferably from 0.25% to 8% by weight, most preferably from 0.5% to 6% by weight of the composition.
Alkyl Ethoxy Sulphate
The second essential component of the composition of the present invention is an alky ethoxy sulphate. The alkyl ethoxy sulphate is preferably a water-soluble salt or acid of the formula RO(A)mSO3M wherein R is an unsubstituted C6-C30 linear or branched alkyl group, preferably a C10-C20 linear or branched alkyl, more preferably C12-C18, most preferably C12-C14 linear or branched alkyl group, A is an ethoxy unit, m is 2 or less, more preferably between 0.05 and 2, most preferably 0.05 to less than 1 mole, and M is H or a cation which can be, for example, a metal cation, preferably an alkali or alkaline earth metal, (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), ammonium or substituted ammonium cation. Specific examples of substituted ammonium cations include methyl-, dimethyl-, trimethyl-ammonium and quaternary ammonium cations, such as tetramethyl-ammonium, dimethyl piperdinium and cations derived from alkanolamines such as ethylamine, diethylamine, triethylamine, mixtures thereof, and the like. Preferred examples of alkyl ethoxy sulphates are selected from the group consisting of C12-C14 ethoxy sulfate. The most preferred alkyl ethoxy sulfate is the sodium salt of lauryl ethoxy (1) sulfate or C12H25OCH2CH2OSO3Na.
The compositions of the present invention provide improved soil removal fabric whiteness and storage stability versus identical compositions, not comprising an alkyl ethoxy sulfate having 2 or less moles of ethoxy groups.
It is believed that the improved soil removal is achieved due to the higher hydrophobicity of the surfactant and thus the higher affinity for soils. Additionally, the lower the ethoxylation degree, the more weight effective the surfactant, i.e., the higher the molar concentration for a given surfactant level in the finished product. The increased affinity for and subsequent solubilisation and removal of soils is perceived as an improvement in fabric whiteness by consumers.
Furthermore, the compositions of the present invention exhibit improved stability versus identical compositions comprising the alkyl ethoxy sulfate with a higher degree of ethoxylation, i.e. greater than 2. It is believed that this stability benefit is achieved because, as the Applicant has found, it is the ethoxy groups of alkyl ethoxy sulfate that are sensitive to hypohalite bleach. Thus, the Applicant has found that by lowering the number of moles of ethoxy groups of 2 or less, the stability of the surfactant and the composition can be improved without adversely affecting solubility of the surfactant.
Viscosity
Typically such compositions according to the present invention have a viscosity between 0 cps and 2000 cps, preferably between 50 cps and 1100 cps. Has a preferred embodiment of the present invention, the viscosity of the composition can be further modified by addition of a co-surfactant. Where present the ratio of alkyl ethoxy sulfate and a co-surfactant will determine the actual viscosity. Viscosity is measured with a rheometer like carri-med CSL2-100(copyright) at the following viscosity parameters angle : 1xc2x058, gap : 60, diameter 4.0 cm, iner: 63.60 at a temperature of 25xc2x0 C. and a shear rate of 30 1/sec.
Optional components
In addition to the essential components described above, the bleaching composition may also comprise one or more optional components. Optional components may be selected from brightener, radical scavenger, chelating agent, pH buffering agent, co-surfactant and polymers.
Brightener
An optional component of the invention is a brightener. Any brighteners known to those skilled in the art may be used herein including both hydrophobic and hydrophilic brighteners and mixtures thereof.
Brighteners are compounds which have the ability to fluorescence by absorbing ultraviolet wave-lengths of light and re-emitting visible light. Brighteners, also referred to as fluorescent whitening agents (FWA), have been extensively described in the art, see for instance EP-A-0 265 041, EP-A-0 322 564, EP-A-0 317 979 or xe2x80x9cFluorescent whitening agentsxe2x80x9d by A. K. Sarkar, published by MERROW, especially page 71-72.
Commercial optical brighteners which may be useful in the present invention can be classified into subgroups, which include, but are not necessarily limited to, derivatives of stilbene, pyrazoline, coumarin, carboxylic acid, methinecyanine, dibenzothiophene-5,5-dioxide, azole, 5- and 6-membered-ring heterocycle, and other miscellaneous agents. Examples of such brighteners are disclosed in xe2x80x9cThe Production and Application of Fluorescent Brightening Agentsxe2x80x9d, M. Zahradnik, Published by John Wiley and Sons, New York (1982). Further optical brighteners which may also be used in the present invention include naphthlimide, benzoxazole, benzofuran, benzimidazole and any mixtures thereof. Particularly preferred brighteners for use herein are the derivatives of stilbene and mixtures thereof.
Examples of optical brighteners which are useful in the present compositions are those identified in U.S. Pat. No. 4,790,856. These brighteners include the PHORWHITE(copyright) series of brighteners from Verona. Other brighteners disclosed in this reference include: Tinopal-UNPA(copyright), Tinopal CBS(copyright) and Tinopal 5BM(copyright) available from Ciba-Geigy; Artic White CC(copyright) and Artic White CWD(copyright); the 2-(4-styryl-phenyl)-2H-naptho[1,2-d]triazoles; 4,4xe2x80x2-bis(1,2,3-triazol-2-yl)-stilbenes; 4,4xe2x80x2-bis(styryl)bisphenyls; and the aminocoumarins.
The Radical Scavenger
An other optional component of the invention is a radical scavenger. Naturally, for the purpose of the present invention, the radical scavengers have to be stable to the hypohalite bleach.
Suitable radical scavengers for use herein include aromatic radical scavengers comprising an unsaturated ring system of from 3 to 20 carbon atoms, preferably of from 3 to 18 and more preferably of from 5 to 14 and having a double bond set comprising a total of 4n+2 electrons, wherein n is an integer of from 0 to 4, preferably of from 1 to 3. Indeed said aromatic radical scavengers include benzene derivatives, naphthalene derivatives, annulene derivatives, cyclopentadiene derivatives, cyclopropene derivatives and the like, especially aryl carboxylates and/or aryl sulfonates.
Particularly suitable radical scavengers (aryl carboxylates, aryl sulphonate and derivatives thereof) for use in the present invention have one of the following formulas:
wherein each X, Y, and Z are xe2x80x94H, xe2x80x94COOxe2x80x94M+, xe2x80x94Cl, xe2x80x94Br, xe2x80x94SO3xe2x80x94M+, xe2x80x94NO2, xe2x80x94OCH3, or a C1 to C10 primary and secondary alkyl groups and M is H or an alkali metal, or mixtures thereof. Examples of these components include pyromellitic acid, i.e. where X, Y and Z are xe2x80x94COOxe2x80x94H+; hemimellitic acid, trimellitic acid, i.e. where X and Y are xe2x80x94COOxe2x80x94H+and Z is H. Preferred to be used in the present invention as radical scavengers are phthalic acid; sulfophthalic acid; other mono-substituted phthalic acids; di-substituted benzoic acids; alkyl-, chloro-, bromo-, sulfo-, nitro- and alkoxy- benzoic acids, i.e. where Y and Z are -H and X is a C1 to C10 primary and secondary alkyl groups, xe2x80x94Cl, xe2x80x94Br, xe2x80x94SO3xe2x80x94H+, xe2x80x94NO2, and xe2x80x94OCH3 respectively and substituted sulfonic acids. Preferred examples of the radical scavengers useful in the present invention are benzoic acid, methoxy benzoic acid, 3-nitrobenzoic acid, 4-toluene sulfonic acid, 2 n-octyl benzoic acid, 2 n-octyl sulfonic acid, anisic acid or salts thereof or mixtures thereof. Highly preferred examples of radical scavengers herein are benzoic acid and/or methoxy benzoic acid and/or 3-nitro benzoic acid.
All the radical scavengers described above are the acidic form of the species, i.e. M is H. It is intended that the present invention also covers the salt derivatives of these species, i.e. M is an alkali metal, preferably sodium or potassium. In fact. since the pH of the compositions of the present invention is in the alkaline range, the radical scavengers of the present invention exist primarily as the ionized salt in the aqueous composition herein. The anhydrous derivatives of certain species described herein above can also be used in the present invention, e.g. pyromellitic dianhydride, phthalic anhydride, sulphthalic anhydride and the like.
Where present the radical scavenger may be present at a level of from 0.001% to 10% by weight of the total composition of a radical scavenger, preferably from 0.01% to 8%, more preferably from 0.1% to 6% and most preferably from 0.2% to 4%.
Chelating Agents
In the compositions of the present invention, a chelating agent is an optional but preferred component. Naturally, for the purpose of the present invention, the chelating agents have to be stable to the hypohalite bleach.
Suitable chelating agents may be any of those known to those skilled in the art such as the ones selected from the group comprising phosphonate chelating agents, phosphate chelating agents, polyfunctionally-substituted aromatic chelating agents, ethylenediamine N,Nxe2x80x2-disuccinic acids, or mixtures thereof.
Chelating agents may be desired in the compositions of the present invention, preferably phosphate chelating agents like phytic acid, as they further contribute to the benefit delivered by the radical scavengers herein by further improving the stability of the brighteners, thus delivering effective whiteness performance in any laundry application upon ageing of the compositions, i.e. after prolonged periods of storage. Thus, in its broadest aspect the present invention encompasses the use, in a hypohalite bleaching composition comprising a brightener, of a chelating agent, for improved brightener stability in said composition as well as the use, in a hypohalite bleaching composition comprising a brightener, of a chelating agent, for effective whiteness performance upon ageing of the composition.
The presence of chelating agents may also contribute to reduce tensile strength loss of fabrics and/or colour damage, especially in a laundry pretreatment application. Indeed, the chelating agents inactivate the metal ions present on the surface of the fabrics and/or in the cleaning compositions (neat or diluted) that otherwise would contribute to the radical decomposition of the hypohalite bleach.
Fabric safety may be evaluated by different test methods including the degree of polymerisation test method according to UNI (Ente Nazionale Italiano di Unificazione) official method UNI 8282-Determinazione della viscosita intrinseca in soluzione di cuprietilendiammina (CED).
Suitable phosphonate chelating agents for use herein may include alkali metal ethane 1-hydroxy diphosphonates (HEDP), alkylene poly (alkylene phosphonate), as well as amino phosphonate compounds, including amino aminotri(methylene phosphonic acid) (ATMP), nitrilo trimethylene phosphonates (NTP), ethylene diamine tetra methylene phosphonates, and diethylene triamine penta methylene phosphonates (DTPMP). The phosphonate compounds may be present either in their acid form or as salts of different cations on some or all of their acid functionalities. Preferred phosphonate chelating agents to be used herein are diethylene triamine penta methylene phosphonate (DTPMP) and ethane 1-hydroxy diphosphonate (HEDP). Such phosphonate chelating agents are commercially available from Monsanto under the trade name DEQUEST(copyright).
Suitable phosphate chelating agents are as following: Phosphonic acid can be condensed in the reaction:
The reaction can be repeated with any of the reactive OH groups, and phosphate ingredients are obtained which can be
linear or branched polyphosphates of structure
when R is M or
when M is a counterion, preferably alkali metal; when Oxe2x89xa6n+m less than 500 (if n+m=0 then the compound is phosphonic acid)
cyclic polyphosphates (also referred to as metaphosphates), of structure
when R is M or
if R is
the phosphate compound contains both cycles and branched chain, and can be referred to as an ultraphosphate.)
where M is a counterion, preferably an alkali metal
where Oxe2x89xa6n+m less than 500
All such phosphate ingredients are suitable for use herein, and preferred are linear phosphate ingredients (i.e. R is M) where n is 1 (pyrophosphate) and n is 2 (tripolyphosphate (STPP)), most preferably where n is 2. The most commonly available form of these phosphate is where M is Sodium.
Phytic acid, which is particularly suitable for use herein, is a hexa-phosphoric acid that occurs naturally in the seeds of many cereal grains, generally in the form of the insoluble calcium-magnesium salt. It may also be derived from corn steep liquor. Commercial grade phytic acid is commercially available from J.T. Baker Co., e.g. as a 40% aqueous solution. It is intended that the present invention covers the acidic form of phytic acid as well as alkali metal salt derivatives thereof, particularly sodium or potassium salts thereof. Sodium phytate is available from Jonas Chemical Co (Brooklyn, N.Y.). In fact since the typical pH of the compositions of the present invention are in the alkaline pH range, the phytic acid component exists primarily as the ionized salt in the liquid compositions herein even if it is added in its acidic form. Mixtures of such salts of phytic acid are also covered.
Polyfunctionally-substituted aromatic chelating agents may also be useful in the compositions herein. See U.S. Pat. No. 3,812,044, issued May 21, 1974, to Connor et al. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy -3,5-disulfobenzene.
A preferred biodegradable chelating agent for use herein is ethylene diamine N,Nxe2x80x2-disuccinic acid, or alkali metal, or alkaline earth, ammonium or substitutes ammonium salts thereof or mixtures thereof. Ethylenediamine N,Nxe2x80x2-disuccinic acids, especially the (S,S) isomer have been extensively described in U.S. Pat. No. 4,704,233, Nov. 3, 1987, to Hartman and Perkins. Ethylenediamine N,Nxe2x80x2-disuccinic acids is, for instance, commercially available under the tradename ssEDDS(copyright) from Palmer Research Laboratories.
Particularly preferred chelating agents for use herein are phosphate chelating agents like sodium pyrophosphate, sodium tripolyphosphate, phytic acid, and mixtures thereof.
Typically, the compositions according to the present invention comprise up to 10% by weight of the total composition of a chelating agent, or mixtures thereof, preferably from 0.01% to 5% by weight, more preferably from 0.05% to 2% and most preferably from 0.1% to 1.5%.
pH
The liquid compositions of the present invention have a pH of preferably from 8 to 14, more preferably from 9 to 14, most preferably from 10 to 13. When diluted into 1 to 500 times its weight of water, the pH of the diluted solution is preferably from 7.5 to 13, more preferably from 8 to 12, most preferably from 8.5 to 11.5. It is in this alkaline range that the optimum stability and performance of the hypohalite, as well as fabric whiteness and/or safety are obtained. The pH range is suitably provided by the hypohalite bleach mentioned hereinbefore and optionally the pH buffering component when present, which are alkalis. However, in addition to these components, a strong source of alkalinity may also optionally be used.
Suitable sources of alkalinity are the caustic alkalis such as sodium hydroxide, potassium hydroxide and/or lithium hydroxide, and/or the alkali metal oxides such as sodium and/or potassium oxide. A preferred strong source of alkalinity is a caustic alkali, more preferably sodium hydroxide and/or potassium hydroxide. Typical levels of such caustic alkalis, when present, are of from 0.1% to 1.5% by weight, preferably from 0.5% to 1.5% by weight of the composition.
Optional pH Buffering Components
In the compositions of the present invention, the presence of a pH buffering component is not compulsory, but is highly preferred.
The pH buffering component ensures that the pH of the composition and diluted solution are buffered to pH range described above.
Suitable pH buffering components for use herein are selected from the group consisting of alkali metal salts of carbonates, polycarbonates, sesquicarbonates, silicates, polysilicates, boron salts, phosphates, stannates, alluminates and mixtures thereof. The preferred alkali metal salts for use herein are sodium and potassium.
Suitable boron salts or mixtures thereof for use herein include alkali metal salts of borates and alkyl borates and mixtures thereof. Examples of boron salts include boric acid, alkali metal salts of metaborate, tetraborate, octoborate, pentaborate, dodecaboron, borontrifluoride and alkyl borate containing from 1 to 12 carbon atoms, preferably from 1 to 4. Suitable alkyl borate includes methyl borate, ethyl borate and propyl borate. Particularly preferred boron salts herein are the alkali metal salts of metaborate, such as sodium metaborate, potassium metaborate, and the alkali metal salts of borate, such as sodium borate, or mixtures thereof. Boron salts like sodium metaborate and sodium tetraborate are commercially available from Borax and Societa Chimica Larderello under the name sodium metaborate and Borax(copyright).
Particularly preferred pH buffering components are selected from the group consisting of sodium carbonate, sodium silicate, sodium borate, sodium metaborate and mixtures thereof.
The raw materials involved. in the preparation of hypohalite bleaches usually contain by-products, e.g calcium carbonate resulting in an amount of up to 0.4% by weight of by-product within the hypohalite composition. However, at such amount, the by-product will not have the buffering action defined above.
Liquid bleaching compositions herein will preferably contain an amount of pH buffering component of from 0.5% to 9% by weight, more preferably from 0.5% to 5% by weight, and most preferably in an amount of from 0.6% to 3% by weight of the composition.
The composition according to the invention may comprise other optional components such as bleach-stable surfactants, organic or inorganic alkalis, builders, thickening agents, polymers, pigments, dyes, solvents, perfumes, and mixtures thereof.
Optional Co-surfactants
The liquid compositions of the present invention may further comprise a co-surfactant or a mixture thereof as an optional ingredient. Said co-surfactants may be present in the compositions according to the present invention in amounts of preferably from 0.1% to 50% by weight of the total composition, more preferably of from 0.1% to 40% and most preferably of from 1% to 30%.
Surfactants suitable for use herein as co-surfactants include additional anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, zwitterionic surfactants, and mixtures thereof.
Suitable anionic surfactants for use in the compositions herein include water-soluble salts or acids of the formula ROSO3M wherein R preferably is a C10-C24 hydrocarbyl, preferably linear or branched alkyl having a C10-C20 alkyl component, more preferably a C12-C18 linear or branched alkyl, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium), or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl-ammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like.
Other suitable additional anionic surfactants are alkyl propoxylated sulfates, preferably having from 0.5 to 30, more preferably 0.5 to 5 moles of propoxy groups.
Other anionic surfactants useful for detersive purposes can also be used herein. These can include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of soap, C9-C20 linear alkylbenzenesulfonates, C8-C22 primary or secondary alkanesulfonates, C8-C24 olefinsulfonates, sulfonated polycarboxylic acids prepared by sulfonation of the pyrolyzed product of alkaline earth metal citrates, e.g., as described in British patent specification No. 1,082,179, C8-C24 alkylpolyglycolethersulfates (containing up to 10 moles of ethylene oxide); alkyl ester sulfonates such as C14-16 methyl ester sulfonates; acyl glycerol sulfonates, fatty oleyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, paraffin sulfonates, alkyl phosphates, isethionates such as the acyl isethionates, N-acyl taurates, alkyl succinamates and sulfosuccinates, monoesters of sulfosuccinate (especially saturated and unsaturated C12-C18 monoesters) diesters of sulfosuccinate (especially saturated and unsaturated C6-C14 diesters), sulfates of alkylpolysaccharides such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated compounds being described below), branched primary alkyl sulfates, alkyl polyethoxy carboxylates such as those of the formula RO(CH2CH2O)kCH2COOxe2x80x94M+ wherein R is a C8-C22 alkyl, k is an integer from 0 to 10, and M is a soluble salt-forming cation. Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tall oil. Further examples are given in xe2x80x9cSurface Active Agents and Detergentsxe2x80x9d (Vol. I and II by Schwartz, Perry and Berch). A variety of such surfactants are also generally disclosed in U.S. Pat. No. 3,929,678, issued Dec. 30, 1975, to Laughlin, et al. at Column 23, line 58 through Column 29, line 23 (herein incorporated by reference).
Other suitable anionic surfactants for use herein also include acyl sarcosinate or mixtures thereof, in its acid and/or salt form, preferably long chain acyl sarcosinates having the following formula:
wherein M is hydrogen or a cationic moiety and wherein R is an alkyl group of from 11 to 15 carbon atoms, preferably of from 11 to 13 carbon atoms. Preferred M are hydrogen and alkali metal salts, especially sodium and potassium. Said acyl sarcosinate surfactants are derived from natural fatty acids and the amino-acid sarcosine (N-methyl glycine). They are suitable to be used as aqueous solution of their salt or in their acidic form as powder. Being derivatives of natural fatty acids, said acyl sarcosinates are rapidly and completely biodegradable and have good skin compatibility.
Accordingly, suitable long chain acyl sarcosinates to be used herein include C12 acyl sarcosinate (i.e., an acyl sarcosinate according to the above formula wherein M is hydrogen and R is an alkyl group of 11 carbon atoms) and C14 acyl sarcosinate (i.e., an acyl sarcosinate according to the above formula wherein M is hydrogen and R is an alkyl group of 13 carbon atoms). C12 acyl sarcosinate is commercially available, for example, as Hamposyl L-30(copyright) supplied by Hampshire. C14 acyl sarcosinate is commercially available, for example, as Hamposyl M-30(copyright) supplied by Hampshire.
Suitable nonionic surfactants for use herein include a class of compounds which may be broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be branched or linear aliphatic (e.g. Guerbet or secondary alcohol) or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical 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. Accordingly suitable nonionic synthetic surfactants include
(i) The polyethylene oxide condensates of alkyl phenols, e.g., the condensation products of alkyl phenols having an alkyl group containing from 6 to 20 carbon atoms in either a straight chain or branched chain configuration, preferably from 8 to 12 carbon atoms, with ethylene oxide, the said ethylene oxide being present in amounts equal to 10 to 25 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived from polymerized propylene, diisobutylene, octane, and nonane;
(ii) Those derived from the condensation of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine products which may be varied in composition depending upon the balance between the hydrophobic and hydrophilic elements which is desired. Examples are compounds containing from about 40% to about 80% polyoxyethylene by weight and having a molecular weight of from about 5000 to about 11000 resulting from the reaction of ethylene oxide groups with a hydrophobic base constituted of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of the order of 2500 to 3000;
(iii) The condensation product of aliphatic alcohols having from 6 to 22 carbon atoms, in either straight chain or branched chain configuration, preferably from 8 to 18 carbon atoms, with from 2 to 35 moles of ethylene oxide, preferably from 4 to 25 and more preferably from 5 to 18. Example of this type of material are a coconut alcohol ethylene oxide condensate having from 5 to 18 moles of ethylene oxide per mole of coconut alcohol, the coconut alcohol fraction having from 9 to 14 carbon atoms;
(iv) Trialkyl amine oxides and trialkyl phosphine oxides wherein one alkyl group ranges from 10 to 18 carbon atoms and two alkyl groups range from 1 to 3 carbon atoms; specific example is tetradecyl dimethyl phosphine oxide;
(v) The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol; The hydrophobic portion of these compounds will preferably have a molecular weight of from about 1500 to about 1800 and will exhibit water insolubility. The addition of polyoxyethylene moieties to this hydrophobic portion tends to increase the water solubility of the molecule as a whole, and the liquid character of the product is retained up to the point where the polyoxyethylene content is about 50% of the total weight of the condensation product, which corresponds to condensation with up to about 40 moles of ethylene oxide.
Particularly suitable nonionic. surfactants for use herein are capped nonionic ethoxylated surfactants according to the formula:
R1(OR2)nOR3
wherein
R1 is a C8-C18 linear or branched alkyl or alkenyl group, aryl group, alkaryl group, preferably, R1 is a C10-C15 alkyl or alkenyl group, more preferably a C10-C15 alkyl group;
R2 is a C2-C10 linear or branched alkyl group, preferably a C4 group;
R3 is a C1-C10 alkyl or alkenyl group, preferably a C1-C5 alkyl group, and
n is an integer ranging in the range of from 1 to 20, preferably from 1 to 10, more preferably from 1 to 5;
or mixtures thereof.
These surfactants are commercially available from BASF under the trade name Plurafac(copyright), from HOECHST under the trade name Genapol(copyright) or from ICI under the trade name Symperonic(copyright). Preferred capped nonionic ethoxylated surfactant of the above formula are those commercially available under the tradename Genapol(copyright) L 2.5 NR from Hoechst, and Symperonic(copyright)LF/CS 1100 from ICI.
Other suitable nonionic surfactants for use herein include the amine oxides corresponding to the formula:
RRxe2x80x2Rxe2x80x3Axe2x86x92O
wherein R is a primary alkyl group containing 6-24 carbons, preferably 10-18 carbons, and wherein Rxe2x80x2 and Rxcex94 are, each, independently, an alkyl group containing 1 to 6 carbon atoms. The arrow in the formula is a conventional representation of a semi-polar bond. The preferred amine oxides are those in which the primary alkyl group has a straight chain in at least most of the molecules, generally at least 70%, preferably at least 90% of the molecules, and the amine oxides which are especially preferred are those in which R contains 10-18 carbons and Rxe2x80x2 and Rxe2x80x3 are both methyl. Exemplary of the preferred amine oxides are the N-hexyldimethylamine oxide, N-octyldimethylamine oxide, N-decyldimethylamine oxide, N-dodecyl dimethylamine oxide, N-tetradecyldimethylamine oxide, N-hexadecyl dimethylamine oxide, N-octadecyidimethylamine oxide, N-eicosyldimethylamine oxide, N-docosyldimethylamine oxide, N-tetracosyl dimethylamine oxide, the corresponding amine oxides in which one or both of the methyl groups are replaced with ethyl or 2-hydroxyethyl groups and mixtures thereof. A most preferred amine oxide for use herein is N-decyldimethylamine oxide.
Other suitable nonionic surfactants for the purpose of the invention are the phosphine or sulfoxide surfactants of formula:
RRxe2x80x2Rxe2x80x3Axe2x86x92O
wherein A is phosphorus or sulfur atom, R is a primary alkyl group containing 6-24 carbons, preferably 10-18 carbons, and wherein Rxe2x80x2 and Rxe2x80x3 are, each, independently selected from methyl, ethyl and 2-hydroxyethyl. The arrow in the formula is a conventional representation of a semi-polar bond.
Suitable zwitterionic detergents for use herein comprise the betaine and betaine-like detergents wherein the molecule contains both basic and acidic groups which form an inner salt giving the molecule both cationic and anionic hydrophilic groups over a broad range of pH values. Some common examples of these detergents are described in U.S. Pat. Nos. 2,082,275, 2,702,279 and 2,255,082, incorporated herein by reference. Preferred zwitterionic detergent compounds have the formula:
wherein R1 is an alkyl radical containing from 8 to 22 carbon atoms, R2 and R3 contain from 1 to 3 carbon atoms, R4 is an alkylene chain containing from 1 to 3 carbon atoms, X is selected from the group consisting of hydrogen and a hydroxyl radical, Y is selected from the group consisting of carboxyl and sulfonyl radicals and wherein the sum of R1, R2 and R3 radicals is from 14 to 24 carbon atoms.
Amphoteric and ampholytic detergents which can be either cationic or anionic depending upon the pH of the system are represented by detergents such as dodecylbeta-alanine, N-alkyltaurines such as the one prepared by reacting dodecylamine with sodium isethionate according to the teaching of U.S. Pat. No. 2,658,072, N-higher alkylaspartic acids such as those produced according to the teaching of U.S. Pat. No. 2,438,091, and the products sold under the trade name xe2x80x9cMiranolxe2x80x9d, and described in U.S. Pat. No. 2,528,378, said patents being incorporated herein by reference. Additional synthetic detergents and listings of their commercial sources can be found in McCutcheon""s Detergents and Emulsifiers, North American Ed. 1980, incorporated herein by reference.
Cationic surfactants suitable for use in compositions of the present invention are those having a long-chain hydrocarbyl group. Examples of such cationic surfactants include the ammonium surfactants such as alkyltrimethylammonium halogenides, and those surfactants having the formula:
xe2x80x83[R2(OR3)y][R4(OR3)y]2R5N+Xxe2x88x92
wherein R2 is an alkyl or alkyl benzyl group having from 8 to 18 carbon atoms in the alkyl chain, each R3 is selected from the group consisting of xe2x80x94CH2CH2xe2x80x94, xe2x80x94CH2CH(CH3)xe2x80x94, xe2x80x94CH2CH2CH2xe2x80x94, and mixtures thereof; each R4 is selected from the group consisting of C1xe2x80x94C4 alkyl, benzyl ring structures formed by joining the two R4 groups, and hydrogen when y is not 0; R5 is the same as R4 or is an alkyl chain wherein the total number of carbon atoms of R2 plus R5 is not more than about 18; each y is from 0 to about 10 and the sum of the y values is from 0 to about 15; and X is any compatible anion.
Quaternary ammonium surfactant suitable for the present invention has the formula (I):
whereby R1 is a short chainlength alkyl (C6-C10)
y is 2-4, preferably 3.
whereby R2 is H or a C1-C3 alkyl,
whereby x is 0-4, preferably 0-2, most preferably 0,
whereby R3, R4 and R5 are either the same or different and can be either a short chain alkyl (C1-C3) or alkoxylated alkyl of the formula II,
whereby Xxe2x88x92 is a counterion, preferably a halide, e.g. chloride or methylsulfate.
R6 is C1-C4 and z is 1 or 2.
Preferred quat ammonium surfactants are those as defined in formula I whereby
R1 is C8, C10 or mixtures thereof, x=o,
R3, R4, R5=CH3.
Highly preferred cationic surfactants are the water-soluble quaternary ammonium compounds useful in the present composition having the formula:
R1R2R3R4N+Xxe2x88x92xe2x80x83xe2x80x83(i)
wherein R1 is C8-C16 alkyl, each of R2, R3 and R4 is independently C1-C4 alkyl, benzyl, and xe2x80x94(C2H40)XH where x has a value from 2 to 5, and X is an anion. Not more than one of R2, R3 or R4 should be benzyl.
The preferred alkyl chain length for R1 is C12-C15 particularly where the alkyl group is a mixture of chain lengths derived from coconut or palm kernel fat or is derived synthetically by olefin build up or OXO alcohols synthesis. Preferred groups for R2R3. and R4 are methyl and the anion X may be selected from halide, methosulphate, acetate and phosphate ions. Examples of suitable quaternary ammonium compounds of formulae (i) for use herein are:
coconut trimethyl ammonium chloride or bromide;
decyl triethyl ammonium chloride;
C12-15 trimethyl ammonium chloride or bromide;
myristyl trimethyl ammonium methyl sulphate;
lauryl dimethyl benzyl ammonium chloride or bromide;
lauryl dimethyl (ethenoxy)4 ammonium chloride or bromide;
choline esters (compounds of formula (i) wherein R1 is
di-alkyl imidazolines
Other cationic surfactants useful herein are also described in U.S. Pat. No. 4,228,044, Cambre, issued Oct. 14, 1980 and in European Patent Application EP 000,224.
Polymers
An optional component of the compositions herein is a polymer. That polymer, has surprisingly been found to also reduce the yellowing of the fabrics treated therewith, i.e. improve whiteness, as well as improve fabric safety. Naturally, for the purpose of the invention, the polymer has to be stable to the hypohalite bleach.
Suitable polymers for use are polymers comprising monomeric units selected from the group consisting of unsaturated carboxylic acids, polycarboxylic acids, sulphonic acids, phosphonic acids and mixtures thereof. Co-polymerisation of the above monomeric units among them or with other co-monomers such as styrenesulfonic acid is also suitable.
Preferred examples of such polymers are the polymers and co-polymers of monomeric units selected from the group consisting of acrylic acid, maleic acid, vinylsulphonic acid and mixtures thereof. Also suitable for use herein are the above mentioned polymers and co-polymers which are modified in order to contain other functional groups such as aminophosphohic and/or phosphonic units. More preferred polymers are selected from the group consisting of polyacrylate polymers, co-polymers of acrylic and maleic acid, co-polymers of styrene sulphonic acid and maleic acid, and mixtures thereof, preferably modified with aminophosphonic and/or phosphonic groups.
The molecular weight for these polymers and co-polymers is preferably below 100,000, most preferably between 500 and 50,000. Most suitable polymers and co-polymers for use herein will be soluble in an amount up to 0.1% by weight, in an aqueous composition comprising 5% by weight of sodium hypochlorite with its pH adjusted to 13 with sodium hydroxide.
Commercially available such polymers, suitable for use herein, are the polyacrylate polymers sold under the tradename Good-Rite(copyright) from BF Goodrich, Acrysol(copyright) from Rohm and Haas, Sokalan(copyright) from BASF, Norasol(copyright) from Norso Haas. Also suitable for use herein are the co-polymers of styrene sulphonic acid and maleic acid, commercially available under the tradename Versaflex(copyright) from National Starch such as Versaflex 157, as well as Acumer(copyright) terpolymers from Rohm and Haas, in particular Acumer(copyright) 3100. Preferred commercially available polymers are the polyacrylate polymers, especially the Norasol(copyright) polyacrylate polymers and more preferred are the polyacrylate polymer Norasol(copyright) 410N (MW 10,000) and the polyacrylate polymer modified with phosphonic groups Norasol(copyright) 440N (MW 4000) and its corresponding acid form Norasol(copyright) QR 784 (MW 4000).
A preferred polymer for use herein is a polyacrylate polymer modified with phosphonic groups commercially available under the tradename Norasol(copyright) 440N (MW 4000) and its corresponding acid form Norasol(copyright) OR 784 (MW 4000) from Norso-Haas.
Mixtures of polymers as herein described may also be used in the present invention.
Polymers herein are preferably present in low amounts, i.e. in amounts of up to 10%, preferably up to 1%, more preferably up to 0.5% by weight, even more preferably from 0.001% to 0.3% by weight, and most preferably from 0.005% to 0.2% by weight of the liquid composition.
Method of Bleaching Fabrics
Particularly preferred surfaces to be bleached with the compositions herein are fabrics including for example clothes, curtains, drapes, bed linens, bath linens, table cloths, sleeping bags, tents, upholstered furniture and the like, and carpets.
Thus, the present invention further encompasses a method of bleaching fabrics which comprises the step of contacting said fabrics with a bleaching composition according to the present invention. In a preferred embodiment, the compositions used in said method of bleaching fabrics are liquid hypochlorite-containing compositions that may further comprise a chelating agent and/or a pH buffering component as defined hereinbefore. Said method according to the present invention delivers effective whiteness performance upon ageing of the compositions.
The compositions according to the present invention are preferably contacted to fabrics in a liquid form. Indeed, by xe2x80x9cin a liquid formxe2x80x9d, it is meant herein the liquid compositions according to the present invention per se in neat or diluted form.
The compositions according to the present invention are typically used in diluted form in a laundry operation. By xe2x80x9cin diluted formxe2x80x9d, it is meant herein that the compositions for the bleaching of fabrics according to the present invention may be diluted by the user, preferably with water. Such dilution may occur for instance in hand laundry applications as well as by other means such as in a washing machine. Said compositions can be diluted up to 500 times, preferably from 5 to 200 times and more preferably from 10 to 80 times.
More specifically, the method of bleaching fabrics according to the present invention comprises the steps of first contacting said fabrics with a bleaching composition according to the present invention, in its diluted form, then allowing said fabrics to remain in contact with said composition, for a period of time sufficient to bleach said fabrics, typically 1 to 60 minutes, preferably 5 to 30 minutes, then rinsing said fabrics with water. If said fabrics are to be washed, i.e., with a conventional composition comprising at least one surface active agent, said washing may be conducted together with the bleaching of said fabrics by contacting said fabrics at the same time with a bleaching composition according to the present invention and said detergent composition, or said washing may be conducted before or after that said fabrics have been bleached. Accordingly, said method according to the present invention allows to bleach fabrics and optionally to wash fabrics with a detergent composition comprising at least one surface active agent before the step of contacting said fabrics with said bleaching composition and/or in the step where said fabrics are contacted with said bleaching composition and/or after the step where said fabrics are contacted with the bleaching composition and before the rinsing step and/or after the rinsing step.
In another embodiment of the present invention the method of bleaching fabrics comprises the step of contacting fabrics with a liquid bleaching composition according to the present invention, in its neat form, of allowing said fabrics to remain in contact with said bleaching composition for a period of time sufficient to bleach said fabrics, typically 5 seconds to 30 minutes, preferably 1 minute to 10 minutes and then rinsing said fabrics with water. If said fabrics are to be washed, i.e., with a conventional composition comprising at least one surface active agent, said washing may be conducted before or after that said fabrics have been bleached. In the embodiment of the present invention wherein the liquid bleaching composition of the present invention, is contacted to the fabrics in its neat form, it is preferred that the level of hypohalite bleach, is from 0.01% to 5%, preferably from 0.1% to 3.5%, more preferably from 0.2% to 2% and most preferably from 0.2% to 1%. Advantageously, the present invention provides liquid hypohalite bleach-containing compositions that may be applied neat onto a fabric to bleach, despite a standing prejudice against using hypochlorite-containing compositions neat on fabrics.
It is preferred to perform the bleaching methods herein before said fabrics are washed. Indeed, it has been observed that bleaching said fabrics with the compositions according to the present invention (diluted and/or neat bleaching methods) prior to washing them with a detergent composition provides superior whiteness and stain removal with less energy and detergent than if said fabrics are washed first, then bleached.
Alternatively instead of following the neat bleaching method as described herein above (pretreater application) by a rinsing step with water and/or a conventional washing step with a liquid or powder conventional detergent, the bleaching pre-treatment operation may also be followed by the diluted bleaching method as described herein before either in bucket (hand operation) or in a washing machine.


A system comprises marine geophysical equipment, adapted for towing through a body of water; and tightly fitting covers, attached to the marine seismic equipment, to fill-in indentations in the marine geophysical equipment, for gathering marine geophysical data. A method comprises marine geophysical equipment having tightly fitting covers, to fill-in indentations in the marine geophysical equipment, attached thereto, for gathering marine geophysical data.

1. Field of the Invention
This invention relates generally to the field of geophysical prospecting. More particularly, the invention relates to the field of marine geophysical surveys.
2. Description of the Related Art
In the oil and gas industry, geophysical prospecting is commonly used to aid in the search for and evaluation of subterranean formations. Geophysical prospecting techniques yield knowledge of the subsurface structure of the earth, which is useful for finding and extracting valuable mineral resources, particularly hydrocarbon deposits such as oil and natural gas. Well-known techniques of geophysical prospecting include seismic and electromagnet surveys. The resulting geophysical data are processed to yield information relating to the geologic structure and properties of the subterranean formations in the area being surveyed.
In a marine seismic survey, seismic energy sources are used to generate a seismic signal which, after propagating into the earth, is at least partially reflected by subsurface seismic reflectors. Such seismic reflectors typically are interfaces between subterranean formations having different elastic properties, specifically sound wave velocity and rock density, which lead to differences in acoustic impedance at the interfaces. The reflected seismic energy is detected by seismic sensors (also called seismic receivers) and recorded.
The appropriate seismic sources for generating the seismic signal in marine seismic surveys typically include a submerged seismic source towed by a ship and periodically activated to generate an acoustic wavefield. The seismic source generating the wavefield is typically an air gun or a spatially-distributed array of air guns.
The appropriate types of seismic sensors typically include particle velocity sensors (typically, geophones) and water pressure sensors (typically, hydrophones) mounted within a towed seismic streamer (also known as a seismic cable). Seismic sensors are commonly deployed in sensor arrays within the streamer.
Seismic sources, seismic streamers, and other attached equipment are towed behind survey vessels, attached by cables. The seismic sources and seismic streamers may be positioned in the water by attached equipment, such as deflectors and cable positioning devices (also known as "birds").
Another technique of geophysical prospecting is an electromagnetic survey. Electromagnetic sources and receivers include electric sources plus magnetic sources and receivers. The electric and magnetic receivers can include multi-component receivers to detect horizontal and vertical electric signal components and horizontal and vertical magnetic signal components. In some electromagnetic surveys, the sources and receivers are towed through the water, possibly along with other equipment. The electromagnetic sources and receivers are sometimes towed in streamers, as described above for the seismic receivers.
Unfortunately, marine organisms adhere to nearly everything that moves through water for significant periods of time, including towed geophysical equipment. This adherence of marine organisms is known as "bio-fouling". Bio-fouling is conventionally conceived of in terms of barnacles, but also includes the growth of mussels, oysters, algae, tubeworms, slime, and other marine organisms.
Thus, a need exists for a system and a method for protecting towed geophysical equipment in marine geophysical surveys, especially towed streamers and equipment attached thereto, from marine growth. A need also exists for a system and method for reducing drag resistance on the towed geophysical equipment.

System and method for gathering marine geophysical data


Foamable compositions which exhibit reduced surface tack and better handling characteristics are obtained through the use of specific combinations of epoxy resins. One or more solid epoxy resins are utilized together with liquid and/or semi-solid epoxy resins. The compositions, which preferably contain hollow glass microspheres, are capable of providing foams which are useful in the manufacture of reinforced structural members.

This application claims priority from International application PCT/EP00/01474, filed Feb. 23, 2000, and German application DE 19909270.2, filed Mar. 3, 1999.
1. Field of the Invention
The invention pertains to reduced tack foamable compositions based on epoxy resins. More specifically, particular combinations of epoxy resins containing solid epoxy resins are utilized to obtain putties which are sufficiently low in surface tackiness to be readily handled, yet are pliable enough to be shaped to conform to non-planar surfaces.
2. Discussion of the Related Art
It is known that a number of industries, e.g., the automobile industry, require parts that are both strong and light-weight. One attempt to achieve this balance between strength and minimal weight provides for hollow metal parts. However, hollow metal parts are easily distorted. Accordingly, it is also known that the presence of structural foam in the cavities of the hollow parts can improve the strength and stiffness of such parts.
Generally, such foams comprise a thermosettable resin such as an epoxy resin, a blowing agent and a filler. Preferably, these foams have a density of about 20-40 lb/ft3 (about 0.30 to about 0.65 g/cc) and are able to withstand heat in excess of 175xc2x0 C., more preferably in excess of 200xc2x0 C. Optional ingredients include accelerators, curing agents, processing aids, stabilizers, colorants, and UV absorbers.
Specific formulas for structural foam vary widely and are widely found. For example, U.S. Pat. No. 5,575,526 teaches several resin-based structural foams including Formula 2, which contains 54.5% EPON 828 epoxy resin, 7.5% HALOXY 62 epoxy diluent, 6.1% DER 732 flexible epoxy, 2.0% EXPANCEL 551DU blowing agent, 8.8% MICROS microspheres, 17.7% 3M K20 microspheres and 3.4% DI-CY dicyandiamide curing agent. U.S. Pat. No. 5,755,486 discloses thermally expandable resin-based materials containing, for example, epoxy resin, acrylonitrile-butadiene rubber, calcium carbonate, carbon black, fumed silica, glass spheres, curing agent, accelerator, and blowing agent. Structural foams such as, e.g., Terocore(copyright) (a product of Henkel Surface Technologies), are now used in a variety of industries.
One recurrent problem with many of the structural foam formulations of this type that have been developed to date has been their relatively high degree of tack.
In many of the end-use applications in which structural foams are employed, a desired quantity of the structural foam in its uncured, unfoamed state must be placed on or near the surface of a metal part. Said surface may be somewhat difficult to access due to its proximity to other surfaces, thus often requiring the foamable composition to be applied manually. It will typically be desirable to have the foamable composition be sufficiently pliable or dough-like in consistency so that it may be easily shaped and otherwise manipulated to approximately follow the contours of the surface to which it is being applied.
Certain known structural foam formulations provide excellent strength and other physical properties when foamed and cured, yet are somewhat difficult to work with due to their pronounced xe2x80x9cstickinessxe2x80x9d prior to curing. The uncured formulation thus often does not separate cleanly from the hands or gloves of the operator who is applying the formulation to the structural member or the like into which the formulation is to be incorporated as a composite. A similar problem exists where tools or other machinery are utilized in the application of the foamable formulation. Residue from the uncured formulation consequently tends to build up on the application instruments being used, requiring periodic disposal or cleaning. Besides wasting a portion of the foamable formulation, productivity suffers due to the cleaning time required. It would therefore be very desirable to modify the properties of such foamable compositions in order to lower the surface tackiness, without significantly affecting either the pliability of the composition or its performance when foamed and cured.
It has now been surprisingly discovered that the excessive tackiness problems encountered in previously known structural foam formulations based on liquid and/or semi-solid epoxy resins may be effectively alleviated through the use of solid epoxy resins. The dough or putty thereby obtained may stil be easily formed into any desired configuration, yet leaves little or no residue on the instruments (e.g., hands, gloves, tools) used for such manipulation. Reduced tack foamable compositions thus are provided which comprise one or more base epoxy resins selected from the group consisting of liquid epoxy resins and semi-solid epoxy resins, one or more blowing agents, and one or more curatives, and an amount of one or more solid epoxy resins effective to reduce the surface tackiness of the foamable composition as compared to the surface tackiness of an analogeous foamable composition which does not contain any solid epoxy resin. Such compositions when foamed and cured furnish structural foams having excellent physical properties, including high strength and heat resistance.
Preferred foam formulations contain about 35 weight percent to about 85 weight percent total of epoxy resins, about 5 weight percent to about 60 weight percent of fillers (preferably, including about 5 weight percent to about 50 weight percent hollow glass microspheres), about 0.1 weight percent to about 5 weight percent of one or more blowing agents, and about 0.1 weight percent to about 10 weight percent of one or more curatives. The foamable composition may also contain varying amounts of other additives such as blowing agent accelerators (activators), adhesion promoters (coupling agents), toughening/flexibilizing agents, thixotropic/rheological control agents, colorants and/or stabilizers. It is particularly advantageous to select formulation components which, when mixed together, provide a foamable dough of putty-like consistency which can be readily molded or shaped into any desired configuration prior to foaming and curing. At the same time, the dough should not exhibit a significant degree of cold flow. That is, the dough should essentially retain its shape over an extended period of time at ambient temperatures.
Selection of the epoxy resins to be utilized is critical to the present invention. As a base epoxy resin, one or more liquid and/or semi-solid epoxy resins are employed. One or more solid epoxy resins are combined with the base epoxy resin to modify the surface tack of the foamable composition thereby obtained, as will be described in more detail hereinafter. Characterization herein of the physical form of a particular epoxy resin (i.e., xe2x80x9cliquidxe2x80x9d, xe2x80x9csemi-solidxe2x80x9d, xe2x80x9csolidxe2x80x9d) is in reference to its form at approximately room temperature (i.e., about 25xc2x0 C.). Semi-solid epoxy resins are those epoxy resins which are neither completely solid nor completely liquid at room temperature.
Generally speaking, epoxy resins are those thermosettable resins having an average of more than one (preferably, about two or more) epoxy groups per molecule.
Epoxy resins are well-known in the art and are described, for example, in the chapter entitled xe2x80x9cEpoxy Resinsxe2x80x9d in the Second Edition of the Encyclopedia of Polymer Science and Engineering, Volume 6, pp. 322-382 (1986). Exemplary epoxy resins include polyglycidyl ethers obtained by reacting polyhydric phenols such as bisphenol A, bisphenol F, bisphenol AD, catechol, or resorcinol, or polyhydric aliphatic alcohols such as glycerin, sorbitol, pentaerythritol, trime thylol propane and polyalkylene glycols with haloepoxides such as epichlorohydrin; glycidylether esters obtained by reacting hydroxycarboxylic acids such as p-hydroxybenzoic acid or beta-hydroxy naphthoic acid with epichlorohydrin or the like; polyglycidyl esters obtained by reacting polycarboxylic acids such as phthalic acid, tetrahydrophthalic acid or terephthalic acid with epichlorohydrin or the like; epoxidated phenolic-novolac resins (sometimes also referred to as polyglycidyl ethers of phenolic novolac compounds); epoxidated polyolefins; glycidylated aminoalcohol compounds and aminophenol compounds, hydantoin diepoxides and urethane-modified epoxy resins.
Preferably, both the base epoxy resin(s) and the solid epoxy resin(s) are glycidyl ethers of polyhydric phenols (with bisphenol A being a particularly preferred polyhydric phenol) containing an average of about 2 epoxy groups per molecule. It is desirable to use base epoxy resins having epoxide equivalent weights in the range of from about 150 to about 350 (more preferably, about 170 to about 300). The solid epoxy resins, on the other hand, preferably have melting points in the range of from about 40xc2x0 C. to about 150xc2x0 C. (more preferably, about 50xc2x0 C. to about 100xc2x0 C.) and epoxide equivalent weights in the range of from about 350 to about 2000 (more preferably, about 375 to about 600). Numerous epoxy resins meeting these requirements are available from commercial sources. Representative commercial resins suitable for use as the base epoxy resin molecule include, but are not limited to, PEP 6134 (available from Peninsula Polymers) and EPON 834 (available from Shell Chemical). Representative commercial resins suitable for use as the solid epoxy resin component include, but are not limited to, ARALDITE CT 6060 (available from Ciba) and EPON 1001 (available from Shell Chemical).
Sufficient solid epoxy resin should be incorporated into the foamable composition so as to impart the desired degree of surface tack to said composition. The optimum surface tack will, of course, vary somewhat depending upon the particular end-use application and conditions under which the foamable composition is to be handled. Generally speaking, however, it will be desirable to add an amount of solid epoxy resin so as to obtain a dough which when manipulated at a temperature of from about 20xc2x0 C. to about 40xc2x0 C. does not leave any residue on the instruments being used to manipulate the dough. At the same time, however, the use of excessive quantities of solid epoxy resin should be avoided as the pliability of the dough may be adversely affected (i.e., the dough may become too stiff to be readily formed into a desired shape prior to foaming and curing). Additionally, some degree of residual surface tack is often desirable in order that the foamable dough when placed in contact with a substrate surface does not readily separate from said surface while the substrate is being further handled prior to curing and foaming. Ideally, the surface tack is adjusted by varying the base epoxy resin: solid epoxy resin ratio to obtain a dough which adheres to a metal surface when pressed into place, yet is capable of being released from said surface without leaving any residue. The types and amounts of the other components of the foamable composition will of course also influence the ratio of base to solid epoxy resin used. For example, the presence of relatively high concentrations of solid fillers may reduce the quantity of solid epoxy resin necessary to achieve a satisfactory tack level. If diluents are incorporated in the foamable composition, then larger amounts of solid epoxy resin may have to be used than would be the case in the absence of the diluents.
The optimum proportions of base epoxy resin(s) to solid epoxy resin(s) will depend upon the particular end-use contemplated as well as the physical and chemical characteristics of the individual resins. For example, if an epoxy resin which is fully liquid at room temperature is selected for use as the base epoxy resin, a somewhat larger amount of a solid epoxy will need to be added to achieve a given level of surface tack than would be the case if a semi-solid epoxy resin were instead utilized as the base epoxy resin. Thus, generally speaking, greater quantities of a given solid epoxy resin will need to be used as the melting (solidification) point of the base epoxy resin decreases. If the solid epoxy resin has a relatively high melting point, then typically a smaller amount will need to be added as compared to a solid epoxy resin having a relatively low melting point.
In general, it has been found that a weight ratio of base epoxy resins to solid epoxy resins in the range of from about 10:1 to about 1:5 will often be suitable, subject to the considerations discussed in detail hereinabove.
The hardening of the thermosettable epoxy utilized in the present invention may be accomplished by the addition of any chemical materials known in the art for curing such resins. Such materials are referred to herein as xe2x80x9ccurativesxe2x80x9d, but also include the substances known to workers in the field as curing agents, hardeners, activators, catalysts or accelerators. While certain curatives promote epoxy resin curing by catalytic action, others participate directly in the invention of the resin and are incorporated into the thermoset polymeric network formed by condensation, chain-extension and/or crosslinking of the epoxy resins.
It is particularly desirable to employ at least one curative which is a nitrogen-containing compound. Such curatives (along with other curatives useful for hardening epoxy resins) are described in the chapter in the Encyclopedia of Polymer Science and Engineering referenced herein. Suitable nitrogen-containing compounds useful as curatives include, amino compounds, amine salts, and quaternary ammonium compounds. Particularly preferred types of nitrogen-containing compounds include amine-epoxy adducts and guanidines. In one desirable embodiment of the invention, two or more different types of these nitrogen-containing compounds are used in combination.
Amine-epoxy adducts are well-known in the art and are described, for example, in U.S. Pat. Nos. 3,756,984, 4,066,625, 4,268,656, 4,360,649, 4,542,202, 4,546,155, 5,134,239, 5,407,978, 5,543,486, 5,548,058, 5,430,112, 5,464,910, 5,439,977, 5,717,011, 5,733,954, 5,789,498, 5,798,399 and 5,801,218, each of which is incorporated herein by reference in its entirety.
Such amine-epoxy adducts are the products of the reaction between one or more amine compounds and one or more epoxy compounds. Carboxylic acid anhydrides, carboxylic acids, phenolic novolac resins, water, metal salts and the like may also be utilized as additional reactants in the preparation of the amine-epoxy adduct or to further modify the adduct once the amine and epoxy have been reacted. Preferably, the adduct is a solid which is insoluble in the epoxy resin component of the present invention at room temperature, but which becomes soluble and functions as an accelerator to increase the cure rate upon heating. While any type of amine could be used (with heterocyclic amines and/or amines containing at least one secondary nitrogen atom being preferred), imidazole compounds are particularly preferred. Illustrative imidazoles include 2-methyl imidazole, 2,4-dimethyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole and the like. Other suitable amines include, but are not limited to, piperazines, piperidines, pyrazoles, purines, and triazoles. Any kind of epoxy compound can be employed as the other starting material for the adduct, including monofunctional, bifunctional, and polyfunctional epoxy compounds such as those described previously with regard to the epoxy resin component. Suitable amine-epoxy adducts are available from commercial sources such as Ajinomoto, Inc., Shell, Pacific Anchor Chemical Company, and the Asahi Chemical Industry Company Limited. The products sold by Ajinomoto under the trademark xe2x80x9cAJICURE PN40xe2x80x9d and xe2x80x9cAJICURE-PN-23xe2x80x9d are especially preferred for use in the present invention.
Dicyandiamide (sold commercially by Air Products under the trademark xe2x80x9cDICYxe2x80x9d) is also a particularly preferred curative, although other guanidine compounds may also be utilized. The curative system may also compare one or more ureas, either above or in combination with other types of curatives (especially guanidines such as dicyandiamide). Suitable ureas include alkyl and aryl substituted ureas. Many such ureas are available commercially, for example, N,Nxe2x80x2-dimethyl urea, which is sold under the trademark xe2x80x9cAMICURE URxe2x80x9d by Air Products. Imidazoles such as 2-ethy-4methyl imidazole may also be used as curatives.
The curative system (i.e., the specific curatives and the amounts of such curatives) should be selected such that it does not catalyze curing of the foamable composition to any significant extent under typical storage conditions over an extended period of time. Preferably, the components of the curative system are adjusted such that the foamable composition retains a workable consistency (in one embodiment of the invention, a consistency resembling that of a pliable dough or putty) for more than two weeks in storage at 130 F (54xc2x0 C.) and does not expand in volume or decrease in specific gravity under such conditions to an unacceptable extent, yet foams and cures within 10 minutes upon being heated at 150xc2x0 C. or higher to provide a foam comparable in properties to those of a foam obtained from a freshly prepared foamable composition.
Selection of the blowing agent or blowing agents to be used in the present invention is not believed to be particularly critical, although chemical blowing agents in general are preferred over physical blowing agents. Any of the chemical blowing agents known in the art may be employed, with azodicarbonamide (also sometimes referred to as 1,1xe2x80x2-azobisformamide, AZDC, or ADC) and sulfonyl hydrazides providing particular good performance. Azodicarbonamide is available from a number of commercial sources; for example, it is sold under the trademark UNICELL by Doug Jin Chemical of South Korea and under the CELOGEN trademark by Uniroyal Chemical. xe2x80x9cActivatedxe2x80x9d or xe2x80x9cmodifiedxe2x80x9d forms of azodiacarbonamide may be used to advantage. In some formulations, it may be desirable to also use a blowing agent accelerator (activator) such as a urea so as to lower the temperature at which release of the gas from the blowing agent takes place. Typically, about 0.05% to about 2% blowing agent accelerator based on the weight of the foamable composition is employed, although the optimum amount will, of course, vary depending upon the accelerator selected, the amount of blowing agent, cure temperature and other variables. Excess accelerator should not be present in the foamable composition, however, since the storage stability may be undesirably compromised.
It will be especially desirable to include one or more glass fillers in the foamable composition, as such fillers have been found to impart useful characteristics to the resulting foam (especially where it is to be used to reinforce a structural member). For example, hollow glass microspheres may be added to reduce the density of the foam and thus the overall weight of the reinforced structural member while maintaining good stiffness and strength. Commercially available glass microspheres (sometimes also referred to as glass microballoons or microbubbles) include the materials sold by Minnesota Mining and Manufacturing under the trademark SCOTCHLITE, with suitable grades including those sold under the designations B38, C15, K20 and VS 5500. The glass microspheres preferably have diameters in the range of from about 5 to about 200 micrometers (preferably, less than about 70 micrometers). The crush strength of the hollow glass microspheres may be selected in accordance with the desired characteristics of the cured thermoset foam or reinforced structural member containing said foam. Microspheres having a crush strength in excess of 500 psi are typically employed, however. Glass fiber is another preferred type of glass filler, since it helps increase the strength and stiffness of the resulting foam. The glass fiber may be chopped, milled or in other physical forms.
Other types of fillers (which includes substances capable of functioning as thixotropic or rheological control agents) may also be optionally present in the foamable composition. Any of the conventional inorganic or organic fillers known in the thermosettable resin art may be used including, for example, fibers other than glass fibers (e.g. wollastinite fibers, carbon fibers, ceramic fibers, aramid fibers), silica (including fumed or pyrogenic silica, which may also function as a thixotropic or rheological control agent), calcium carbonate (including coated and/or precipitated calcium carbonate, which may also act as a thixotropic or rheological control agent, especially when it is in the form of fine particles), alumina, clays, sand, metals (e.g., aluminum powder), microspheres other than glass microspheres (including thermoplastic resin, ceramic and carbon microspheres, which may be solid or hollow, expanded or expandable), and any of the other organic or inorganic fillers known in the epoxy resin field. The quantity of thixotropic agent(s) is desirably adjusted so as to provide a dough which does not exhibit any tendency to flow at room temperature.
Other optional components include diluents (reactive or non-reactive) such as glycidyl ethers, glycidyl esters, acrylics, solvents, and plasticizers, toughening agents and flexibilizers (e.g., aliphatic diepoxides, polyaminoamides, liquid polysulfide polymers, rubbers including liquid nitrile rubbers such as butadiene-acrylonitrile copolymers, which may be functionalized with carboxyl groups, amine groups or the like), adhesion promoters (also known as wetting or coupling agents; e.g., silanes, titanates, zirconates), colorants (e.g., dyes and pigments such as carbon black), stabilizers (e.g., antioxidants, UV stabilizers), and the like.
The formulations of the present invention preferably contain the above-discussed components in the following amounts (expressed as a percentage of the total weight of the foamable composition).
Preferably, epoxy resin is present in an amount which is greater than the amount of any of the other components in the foamable composition.
The above-described ingredients may simply be combined and mixed to form the foamable composition using any of the processing methods known in the epoxy resin art. It may be desirable to pre-mix the individual epoxy resins (i.e., the base epoxy resin(s) and solid epoxy resin(s)) before combining with the other components of the formulation.
The preferred finished product preferably has the consistency of dough for easier handling. The dough may be shaped by extrusion, by hand, or by cutting means into any desired configuration, thickness or size. For example, the dough may be extruded to a wide, flat continuous ribbon which can then be cut to a desired length and applied to the surface of a solid article, being conformed to follow the contours of said surface. The dough can then be cured and foamed by heating, preferably at a temperature of at least about 250xc2x0 F. (about 120xc2x0 C.), more preferably to at least about 300xc2x0 F. (about 150xc2x0 C.). Preferably, it is placed on or near the surface of a solid article comprised of, for example, metal or a thermoset or thermoplastic polymer such that a composite of the structural foam adhered to said surface is created upon foaming and curing. The foamable compositions of this invention are also useful for forming laminates, wherein the foamable composition is sandwiched between layers of different substrates (metal or plastic sheets or films, for example) Alternatively, of course, the dough can be placed in a suitable container or vessel for storage until the use of the foamable composition is desired.
The foamable compositions of the present invention may be utilized in any end-use application where a relatively light-weight, yet strong, thermoset foam is needed. However, the foamable compositions are especially useful in the production of automobiles and other vehicles to maintain or increase the strength of structural members such as rockers, pillars, radiator support beams, doors, reinforcing beams, and the like. The use of structural foams in such applications is described, for example, in U.S. Pat. Nos. 4,901,500; 4,908,930; 4,751,249; 4,978,562; 4,995,545; 5,124,186; 5,575,526; 5,755,486; 5,884,960; 5,888,600; 4,923,902; 4,922,596; 4,861,097; 4,732,806; 4,695,343; and 4,610,836 and European Patent Publication Nos. EP 0891918, EP 893331 and EP 0893332 and International Patent Publication Nos. WO 99/08854 (each of which is incorporated herein by reference in its entirety).

Heat-curable, thermally expandable moulded park