GB1602234A

GB1602234A - Thickened acid cleaner

Info

Publication number: GB1602234A
Application number: GB21776/78A
Authority: GB
Original assignee: BASF Wyandotte Corp
Current assignee: BASF Corp
Priority date: 1977-05-25
Filing date: 1978-05-24
Publication date: 1981-11-11
Also published as: CA1095805A; FR2392106A1; ZA782974B; NL7805696A; FR2392106B1; BE867457A; AU3641778A; AU520251B2

Description

Such a concentrate when diluted with 1 to 8, particularly 1 to 2, parts by volume of water per part by volume of concentrate may be used to remove siliceous and/or oily soils from metal surfaces, e.g. metal vehicles, without a subsequent alkaline rinsing by flowing a continuous coat of the diluted cleaner concentrate onto the surface to be cleaned, allowing the cleaner to remain on the surface for a period of time, and rinsing the surface with water under impingement force pressure.

The phosphoric acid employed in this invention may be either the 75% or the 100% by weight strength phosphoric acid. It is preferred that this is the only acid employed in this composition. In view of regulatory restrictions regarding environmental control and waste plant treatment restrictions the presence of acids such as hydrochloric, sulfuric and organic acids such as oxalic, tartaric or citric is not advised or may be prohibited. Accordingly, phosphoric acid is the acid to be employed in this composition. On a weight percent basis the acid cleaner of this invention will contain from 7 to 60 percent aqueous acid (calculated as at least 75% strength acid and more preferably the acid content will be from 20 to 30 weight percent.

The second component of the invented composition is selected from aliphatic alcohols, glycol ethers and mixtures thereof, particularly those wherein the alcohol contains from one to four carbon atoms, the glycol portion of the glycol ether contains from two to nine carbon atoms and the alkyl portion of the glycol ether contains from one to four carbon atoms. Among the alcohols contemplated are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tertiary butyl. The preferred alcohols are methyl, ethyl, and isopropyl alcohol. Preferred ethers are monoethers.

The glycol ethers employed may be monomethyl, ethyl, n- and isopropyl, n- and isobutyl ethers of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol and tripropylene glycol. The preferred glycol ethers are the alkyl ethers of ethylene glycol.

The particular surfactants employed in the compositions according to the invention, in addition to having a cleaning effect, also exhibit unusual thickening properties for this composition. Therefore the surfactants of this invention are doubly critical. The nonionic surfactant is present in an amount from 7 to 23 weight percent of the final composition, more preferably in an amount from 12 to 18 weight percent.

The nonionic surfactants advantageously employed in the compositions of the invention are generally the polyoxyalkylene adducts of hydrophobic bases wherein the oxygen/carbon atom ratio in the oxyalkylene portion of the molecule is greater than 0.4:1. Those compositions which are condensed with hydrophobic bases to provide a polyoxyalkylene portion having an oxygen/carbon atom ratio greater than 0.4:1 include ethylene oxide, butadiene dioxide and glycidol, mixtures of these alkylene oxides with each other and with minor amounts of propylene oxide, butylene oxide, amylene oxide, styrene oxide, and other higher molecular weight alkylene oxides. Ethylene oxide, for example, is condensed with the hydrophobic base in an amount sufficient to impart water dispersibility or solubility and surface active properties to the molecule being prepared.The exact amount of ethylene oxide condensed with the hydrophobic base will depend upon the chemical characteristics of the base employed and is readily apparent to those of ordinary skill in the art relating to the synthesis of oxyalkylene surfactant condensates.

Typical hydrophobic bases which can be condensed with ethylene oxide in order to prepare nonionic surfactants include mono- and polyalkyl phenols, polyoxypropylene condensed with a base having from 1 to 6 carbon atoms and at least one reactive hydrogen atom, fatty acids, fatty amides and fatty alcohols. The hydrocarbon ethers such as the benzyl or lower alkyl ether of the polyoxyethylene surfactant condensates are also advantageously employed in the compositions of the invention.

Examples of nonionic surfactants are the polyoxyethylene condensates of alkyl phenols having from 6 to 20 carbon atoms in the alkyl portion adn from 5 to 30 ethenoxy groups in the polyoxyethylene radical. The alkyl substituent on the aromatic nucleus may for example be octyl, diamyl, n-dodecyl, polymerized propylene such as propylene tetramer and trimer, isoctyl or nonyl.The benzyl ethers of the polyoxyethylene condensates of monoalkyl phenols impart good properties to the compositions of the invention and a typical product corresponds to the formula:

Higher polyalkyl oxyethylated phenols corresponding to the formula:

where R is hydrogen or an alkyl radical having from 1 to 12 carbon atoms, Rl and R2 are alkyl radicals having from 6 to 16 carbon atoms and n has a value from 5 to 30 are also suitable as nonionic surface active agents. A typical oxyethylated polyalkyl phenol is dinonyl phenol condensed with 14 moles of ethylene oxide.

Other nonionic surfactants are cogeneric mixtures of conjugated polyoxyalkylene compounds containing in their structure at least one hydrophobic oxyalkylene chain in which the oxygen/carbon atom ratio does not exceed 0.4:1 and at least one hydrophilic oxyalkylene chain in which the oxygen/carbon atom ratio is greater than 0.4:1.

Polymers of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide, styrene oxide, mixtures of such oxyalkylene groups with each other and with minor amounts of polyoxyalkylene groups obtained from ethylene oxide, butadiene dioxide, and glycidol are illustrative of hydrophobic oxyalkylene chains having an oxygen/carbon atom ratio not exceeding 0.4:1. Polymers of oxyalkylene groups obtained from ethylene oxide, butadiene dioxide, glycidol, mixtures of such oxyalkylene groups with each other and with minor amounts of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide and styrene oxide are illustrative of hydrophilic oxyalkylene chains having an oxygen/carbon atom ratio greater than 0.4:1.

Further nonionic surfactants are the polyoxyethylene esters of higher fatty acids having from 8 to 22 carbon atoms in the acyl group and from 5 to 30 ethenoxy units in the oxyethylene portion. Typical products are the polyoxyethylene adducts of tall oil, rosin acids. lauric, stearic and oleic acids and the like. Additional nonionic surface active agents are the polyoxyethylene condensates of higher fatty acid amines and amides having from 8 to 22 carbon atoms in the fatty alkyl or acyl group and 10 to 30 ethenoxy units in the oxyethylene portion. Illustrative products are coconut oil fatty acid amides condensed with 5 to 30 moles of ethylene oxide.

Other polyoxyalkylene nonionic surfactants are the alkylene oxide adducts of higher aliphatic alcohols and thioalcohols having from 8 to 22 carbon atoms in the aliphatic portion and 5 to 30 in the oxyalkylene portion. Typical products are synthetic fatty alcohols, such as n-decyl, n-undecyl. n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl, n-octadecyl and mixtures thereof condensed with 5 to 30 moles of ethylene oxide, a mixture of normal fatty alcohols condensed with 8 to 20 moles of ethylene oxide and capped with benzyl halide or an alkyl halide, a mixture of normal fatty alcohols condensed with 5 to 30 moles of a mixture of ethylene and propylene oxides, a mixture of several fatty alcohols condensed sequentially with 2 to 20 moles of ethylene oxide and 3 to 10 moles of propylene oxide, in either order; or a mixture of normal fatty alcohols condensed with a mixture of propylene and ethylene oxides, in which the oxygen/carbon atom ratio is less than 0.4:1 followed by a mixture of propylene and ethylene oxides in which the oxygen/carbon atom ratio is greater than 0.4:1 or a linear secondary alcohol condensed with 3 to 30 moles of ethylene oxide, or a linear secondary alcohol condensed with a mixture of propylene and ethylene oxides, or a linear secondary alcohol condensed with a mixture of ethylene, propylene, and higher alkylene oxides.

Of the foregoing described nonionic surfactants, a particularly preferred group is the polyethylene oxide condensates of alkyl phenols, particularly those having an alkyl group containing from 6 to 12 carbon atoms in either a straight chain or branch chain configuration with ethylene oxide, the ethylene oxide being present in amounts equal to 5 to 25 moles of ethylene oxide per mole of alkyl phenol. This group of surfactants is exemplified by octylphenoxy polyethoxyethanol.

The second component of the surfactant system of the compositions according to the invention is an anionic surfactant which is present in an amount from 1 to 7 weight percent and more preferably in an amount from 2 to 3 percent.

Preferred anionic synthetic non-soap detergents can be broadly described as organic sulfuric and sulfonic acid reaction products having in their molecular structure an alkyl radical containing from 8 to 22 carbon atoms and a radical selected from sulfonic acid and sulfuric acid ester radicals. (Included in the term alkyl is the alkyl portion of higher acyl radicals.) Important examples of the synthetic detergents which form a part of the preferred compositions of the present invention are those obtained by sulfating the higher alcohols (C8-C13 carbon atoms) produced by reducing the glycerides of tallow or coconut oil; alkyl benzene sulfonates, in which the alkyl group contains from 9 to 15 carbon atoms, including those of the types described in United States Letters Patent Nos. 2.220,099 and 2,477,383 (the alkyl radical can be a straight or branched aliphatic chain), alkyl glyceryl ether sulfonates, especially those ethers of the higher alcohols derived from tallow and coconut oil: coconut oil fatty acid monoglyceride sulfates and sulfonates; sulfuric acid esters of the reaction product of one mole of a higher fatty alcohol (e.g., tallow or coconut oil alcohols) and 1 to 6 moles of ethylene oxide; sulfuric acid and sulfonic acid esters of the reaction product of one mole of a higher fatty oil (e.g., coconut or castor oil) and 1 to 6 moles of ethylene oxide; alkyl phenolethylene oxide ether sulfate with 1 to 10 units of ethylene oxide per molecule and in which the alkyl radicals contain from 8 to 12 carbon atoms; the reaction product of fatty acids esterified with isethionic acid where, for example, the fatty acids are derived from coconut oil; fatty acid amide of a methyl tauride in which the fatty acids, for example, are derived from coconut oil; and others known in the art, a number being specifically set forth in U.S.Patent Nos. 2,486,921, 2,486,922 and 2,396,278. While less preferred the sodium and potassium salts of the foregoing sulfonic and sulfuric acid and/or ester anionic surfactants can also be used. The foregoing anionic surfactants are further exemplified in McCutcheon's Detergents & Emulsifiers, 1972 Annual, Allured Publishing Corporation, Ridgewood, New Jersey.

Particularly suited for the process and composition of this invention are the alkyl or aryl sulfonic acid anionic surfactants exemplified by a linear alkyl benzene sulfonic acid.

When taken together in considering the foregoing nonionic and anionic surfactants, it is critical to the success of this invention that the total amount of surfactant present constitute from 10 to 30 weight percent of the total cleaner composition and that the nonionic portion of the total surfactant portion be from 75 to 95 weight percent.

The final component of the invented cleaning composition is water which is present in an amount from 83 to 4 percent by weight and preferably in an amount from 80 to 10 weight percent.

In addition to the foregoing ingredients, as is well known in the detergent arts, there can be added to the cleaning composition such things as dyes, perfumes, and corrosion inhibitors, which do not detract from the present invention.

The foregoing acid thickened cleaner concentrate composition may be diluted with water at the point of use to obtain the final cleaning composition. This dilution is preferably about 2 parts by volume of water for each part by volume of cleaner; however, dilution ratios of from 1 part to 8 parts of water per part of cleaner concentrate by volume are satisfactory.

The compositions of this invention may be prepared by standard well-known open kettle mixing techniques known in the industry. A convenient charge schedule for preparation of the composition at room temperature would be to charge the water to the vessel, add the alcohol. followed by the nonionic surfactant, then the anionic surfactant and finally the phosphoric acid. Should it be desired to add other optional modifiers to the composition such as dyes. perfumes and inhibitors they can be added as convenient during the preparation of the composition.

The thickened acid cleaner concentrate after dilution is flowed onto the metal surface, e.g. vehicle. to be cleaned in an amount to obtain physical coverage thereof so that a thin but continuous film is obtained. No brushing, scrubbing or other similar effort is required.

The cleaner is allowed to remain at least one minute and preferably five minutes; however, up to 30 minutes is satisfactory when the surface is cleaned during cold weather. It is an advantage of compositions of the present invention that even if the water component of the composition evaporates during the period of application the cleaner can still be successfully rinsed afterwards. Rinsing is achieved by means of water being sprayed on the vehicle with impingement force and is most conveniently achieved by simply passing the surface, e.g.

vehicle. through the spray rinse. For locomotives a water delivery rate of 150 to 200 gallons per minute and at a pressure of 100 to 200 pounds per square inch is satisfactory. Preferably the rinse will be applied at an angle starting at one end of the locomotive and sweeping forward to the other end and then reversing the angle and sweeping backward to the point of beginning. While the type of vehicle being washed will dictate the type of equipment being used, the acid cleaner composition of this invention is suitable for trucks and trailers, busses. airplanes, railroad engines. boxcars, passenger cars. cabooses, off-road equipment and similar equipment.

Acid cleaner compositions of this invention avoid many of the problems associated with prior art cleaning compositions. For instance, the previously used inert thickeners presented problems in removing the thickener residue after the washing, contributed to dry down problems and the simple disposal problem of the thickener residue after it was removed from the cleaned vehicle. Dry down of course refers to the drying of the cleaner film prior to its removal. It is recognized of course that the acid cleaner can be used with water of any hardness in contrast to alkaline cleaners which are dependent upon a certain degree of water softness in order to obtain desirable effects.In contrast, the present composition with its novel arrangement of surfactants has increased cleaning efficiency, requires no alkaline treatment afterwards, avoids the physical handling problem of the inert thickener residues and additionally facilitates the removal of the organic and oily road soils from the water while the water is in the holding tanks and ponds prior to being discharged into the natural waterways.

The practice of this invention is illustrated by, but not limited by the examples given below. Unless otherwise noted all parts or percents are parts or percents respectively by weight.

Example 1 To an open kettle mixing vessel was charged 51 parts of water followed by 2 parts of isopropyl alcohol. Then 12 parts of octylphenoxy polyethoxyethanol (TRITON X-100 TRITON is a Registered Trade Mark), a nonionic surfactant of the ethoxylated monohydric alcohol type was added. With continuing mixing 4.5 parts of linear alkyl benzene sulfonic acid anionic surfactant of the alkane sulfonate type (CALSOFT LAS-99 CALSOFT is a Registered Trade Mark) was blended in. Finally 30 parts of 75% phosphoric acid was added. The completed thickened acid cleaner was then discharged from the mixing vessel.

The foregoing concentrate was diluted with 2 volumes of water and stirred to obtain a uniform mixture. The acid cleaner composition was then applied to a dirty locomotive.

Approximately 3 gallons were applied to the locomotive. The cleaner was allowed to remain on the locomotive for approximately 5 minutes. The locomotive was then rinsed by driving the locomotive forward through a fixed spray at a speed of 5 to 8 miles an hour and then reversing the locomotive and bringing it back through the fixed sprays once more so that the water was applied at two different angles. The water pressure and delivery rate was 200 gallons of water per minute at 200 pounds per square inch. When dry the locomotive was uniformly clean. free of residual siliceous road soils and oily road soils, had no streaks or spots left from the washing and the painted surface was unaffected by the wash treatment.

Example 2 In this example the cleaning effectiveness of the acid concentrate as prepared in Example 1 at various dilutions was compared. Laboratory cleaning of metal coupons was employed.

The coupons soiled with oil were cleaned by flowing on the cleaner at the dilutions noted below. Upon standing for 10 minutes the coupons were inspected for dry down, i.e., dryness due to evaporation of water. They were then rinsed and evaluated for cleaning. The cleaning or soil removal was rated on a scale of 0 to 10 with 10 being completely clean. A rating of less than 7 is considered unsatisfactory. The results are tabulated below: Concentrated Cleaner Dry Down No Cleaning rate 9 Diluted 1:2 with water Dry Down No Cleaning rate 8 Diluted 1:4 with water Dry Down No Cleaning rate 6 WHAT WE CLAIM IS: 1. A thickened acid cleaner concentrate composition comprising: (1) an aqueous phosphoric acid of at least 75 weight percent strength in an amount from 7 to 60 weight percent, (2) an aliphatic alcohol and/or a glycol ether in an amount from 1 to 6 weight percent,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

film prior to its removal. It is recognized of course that the acid cleaner can be used with water of any hardness in contrast to alkaline cleaners which are dependent upon a certain degree of water softness in order to obtain desirable effects. In contrast, the present composition with its novel arrangement of surfactants has increased cleaning efficiency, requires no alkaline treatment afterwards, avoids the physical handling problem of the inert thickener residues and additionally facilitates the removal of the organic and oily road soils from the water while the water is in the holding tanks and ponds prior to being discharged into the natural waterways.

The practice of this invention is illustrated by, but not limited by the examples given below. Unless otherwise noted all parts or percents are parts or percents respectively by weight.

Example 1 To an open kettle mixing vessel was charged 51 parts of water followed by 2 parts of isopropyl alcohol. Then 12 parts of octylphenoxy polyethoxyethanol (TRITON X-100 TRITON is a Registered Trade Mark), a nonionic surfactant of the ethoxylated monohydric alcohol type was added. With continuing mixing 4.5 parts of linear alkyl benzene sulfonic acid anionic surfactant of the alkane sulfonate type (CALSOFT LAS-99 CALSOFT is a Registered Trade Mark) was blended in. Finally 30 parts of 75% phosphoric acid was added. The completed thickened acid cleaner was then discharged from the mixing vessel.

The foregoing concentrate was diluted with 2 volumes of water and stirred to obtain a uniform mixture. The acid cleaner composition was then applied to a dirty locomotive.

Approximately 3 gallons were applied to the locomotive. The cleaner was allowed to remain on the locomotive for approximately 5 minutes. The locomotive was then rinsed by driving the locomotive forward through a fixed spray at a speed of 5 to 8 miles an hour and then reversing the locomotive and bringing it back through the fixed sprays once more so that the water was applied at two different angles. The water pressure and delivery rate was 200 gallons of water per minute at 200 pounds per square inch. When dry the locomotive was uniformly clean. free of residual siliceous road soils and oily road soils, had no streaks or spots left from the washing and the painted surface was unaffected by the wash treatment.

Example 2 In this example the cleaning effectiveness of the acid concentrate as prepared in Example 1 at various dilutions was compared. Laboratory cleaning of metal coupons was employed.

The coupons soiled with oil were cleaned by flowing on the cleaner at the dilutions noted below. Upon standing for 10 minutes the coupons were inspected for dry down, i.e., dryness due to evaporation of water. They were then rinsed and evaluated for cleaning. The cleaning or soil removal was rated on a scale of 0 to 10 with 10 being completely clean. A rating of less than 7 is considered unsatisfactory. The results are tabulated below: Concentrated Cleaner Dry Down No Cleaning rate 9 Diluted 1:2 with water Dry Down No Cleaning rate 8 Diluted 1:4 with water Dry Down No Cleaning rate 6 WHAT WE CLAIM IS: 1.A thickened acid cleaner concentrate composition comprising: (1) an aqueous phosphoric acid of at least 75 weight percent strength in an amount from 7 to 60 weight percent, (2) an aliphatic alcohol and/or a glycol ether in an amount from 1 to 6 weight percent,

(3) a nonionic surfactant in an amount from 7 to 23 weight percent.

(4) an anionic surfactant in an amount from 1 to 7 weight percent, and (5) water in an amount from 83 to 4 weight percent.

all weight percents being based on the total composition, provided that the said nonionic surfactant and the said anionic surfactant when taken together constitute from 10 to 30 weight percent of said composition and said nonionic surfactant constitutes drom 75 to 90 weight percent of the combined weight of nonionic and anionic surfactants.
2. A composition as claimed in claim 1 wherein the aqueous phosphoric acid is 75% or 100% by weight strength phosphoric acid constituting the sole acid.
3. A composition as claimed in claim 1 or 2 wherein component (2) is selected from aliphatic alcohols containing from one to four carbon atoms, and glycol monoethers of aliphatic alcohols of which the glycol moiety contains from two to nine carbon atoms and the alkyl moiety contains from one to four carbon atoms.
4. A composition as claimed in claim 3 wherein component (2) comprises isopropyl alcohol.
5. A composition as claimed in claim 3 wherein component (2) comprises the mono methyl ether of ethylene glycol.
6. A composition as claimed in any of claims 1 to 5 wherein the nonionic surfactant is a polyoxyalkylene adduct of a hydrophobic base in which the oxygen/carbon atom ratio in the oxyalkylene moiety is greater than 0.4 : 1.
7. A composition as claimed in any of claims 1 to 6 wherein the nonionic surfactant is an alkyl or alkylaryl polyether alcohol.
8. A composition as claimed in any of claims 1 to 7 wherein the anionic surfactant is an alkyl or alkylaryl sulfonic acid.
9. A composition as claimed in any of claims 1 to 8 comprising from 20 to 30 weight percent of component (1), from 2 to 4 weight percent, of component (2) from 12 to 18 weight percent of component (3), from 2 to 3 weight percent of component (4) and from 64 to 45 weight percent of component (5), based on the total composition.
10. A thickened acid cleaner concentrate composition substantially as specifically described and claimed herein or as exemplified in the foregoing Example 1.
11. A thickened acid cleaner composition comprising by volume 1 to 8, particularly 1 to 2, parts of water and 1 part of a thickened acid cleaner concentrate composition as claimed in any of claims 1 to 10.
12. A process for removing siliceous and/or oily sols from metal surfaces without a subsequent alkaline rinsing comprising flowing a continuous coat of a composition as claimed in claim 11 on to the surface to be cleaned, allowing the cleaner to remain on the surface for a period of time, and rinsing the surface with water under impingement force pressure.
13. A process as claimed in claim 12 wherein the surface to be cleaned is the surface of a railway or road vehicle.
14. A process as claimed in claim 12 or 13 wherein the cleaner composition is allowed to remain on the surface for a period of 1 to 30 minutes after application, and is then rinsed twice with water applied with an impinging force so as to mechanically remove the siliceous and oily soil residues.