WO1994003571A1

WO1994003571A1 - Process and aqueous composition for degreasing metal surface

Info

Publication number: WO1994003571A1
Application number: PCT/US1993/006604
Authority: WO
Inventors: Lawrence R. Carlson; Philip M. Johnson; Dennis A. Kent
Original assignee: Henkel Corporation
Priority date: 1992-07-31
Filing date: 1993-07-16
Publication date: 1994-02-17
Also published as: MX9304495A; AU4676893A; ZA935318B; CN1087686A

Abstract

An aqueous alkaline cleaner capable of replacing vapor degreasing for critical aluminum aerospace alloys consists essentially of wter and alkaline phosphate, alkaline borate, nonionic surfactant having an average HLB value within the range from about 7 to about 13, anionic surfactant including partial esters of organophosphonic acids, water-miscible organic solvent, organic corrosion inhibitor, and preferably also alkaline hydroxide and alkaline silicate.

Description

PROCESS AND AQUEOUS COMPOSITION FOR DEGREASING METAL

SURFACE

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to a process for degreasing metal surfaces, especially aluminum and aluminum alloy sur¬ faces used in the aerospace industry. The aqueous based compositions provided by this invention are capable of giv¬ ing results as satisfactory as conventional vapor degreas¬ ing in organic solvents for removing fats, oils, waxes, and greases.

Statement of Related Art

The metal working industry uses numerous mechanical processes such as stamping, cutting, welding, grinding, drawing, machining, and polishing in preparing the very wide variety of metal object manufactured. In most of these operations oily lubricants and the like are used, and as a result an undesirable organic residue is left on the surfaces of the metal parts produces. This residue must be removed in most cases before the metal parts are either given protective surface finishes of any type or employed for their ultimately desired use. In order to achieve such cleaning, it has become com¬ mon to use degreasing compositions such as methyl ethyl ke- tone, methylene chloride, and the like, either at ambient temperature, or in more difficult cases, by exposing soiled metal parts to the vapors of constantly refluxing solvents of this type - a method known as vapor degreasing, Because most of the soil to be removed is composed of materials with substantially higher boiling points than the solvents used in vapor degreasing, the use of condensed vapor of the solvents assures that each fresh batch of metal parts to be cleaned will be exposed to relatively pure solvent with high dissolving power.

Vapor degreasing is technically effective but econom¬ ically and environmentally disadvantageous. The solvents are fairly expensive and are pollutants that require costly methods of disposition to satisfy environmental protection laws. Elaborate apparatus and processes are needed to re¬ claim the dirty compositions for reuse, and the vapors from these solvents are often hazardous to human health. For all these reasons, many attempts have been made to replace vapor degreasing with aqueous based cleaners, but to date none has been entirely satisfactory, particularly in pre¬ paring the aluminum and aluminum alloy surfaces used in the aerospace industry, where the requirement for cleanliness are particularly stringent.

European Patent Application 0 376 367 published July 4, 1990 teaches an aqueous cleaner for metals containing a combination of surfactant, builders, corrosion inhibitor, and alkyl polyethylene glycol ether. PCT Application WO 90/05770 published 31 May 1990 teaches a cleaner for hard surfaces comprising water solu¬ ble solvents and/or solubilizers, organic and/or inorganic builders, and an anionic surfactant component that includes both sulfated hydroxyalkyl-poly(ethylene/ propylene glycol) ethers and dialkyl sulfosuccinates.

U. S. Patent 4,746,453 of May 24, 1988 to Chen et al. teaches a cleaning composition for electrolytic cleaning, comprising alkali hydroxide, silicate, and nonionic sur¬ factant, preferably a combination of lauryl polyethylene glycol ether with about 10 moles of ethylene oxide per lauryl group and nonyl phenyl polyethylene glycol ether with about one mole of ethylene oxide per nonyl phenyl group.

U. S. Patent 4,710,232 of Dec. 1, 1987 to Tahbaz teaches (i) providing an alkaline cleaner comprising an aqueous solution of a soluble salt selected from the group consisting of alkaline carbonates, alkaline phosphates, alkaline silicates, alkaline sulfates, alkaline borates, sodium hydroxide, potassium hydroxide, and mixtures there¬ of; (ii) providing an emulsion cleaner comprising water, an organic solvent that may be or include a glycol ether, and a surfactant; (iii) mixing the alkaline and emulsion clean¬ ers; and (iv) contacting soiled metal surfaces with the mixture formed thereby for a sufficient time to remove the soil from the metal surfaces.

U. S. Patent 3,915,902 of Oct. 28, 1975 to Ancel et al. teaches a cleaning composition containing as its essen¬ tial ingredients (1) water, (2) organic solubilizing agent, which may be an ether alcohol, (3) surfactant, (4) hydro¬ carbon solvent, (5) chlorinated solvent, and (6) inorganic builders.

DESCRIPTION OF THE INVENTION

Except in the claims and the operating examples, or where otherwise expressly indicated, all numerical quant¬ ities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word "about" in describing the broadest scope of the invention. Practice within the exact numeri¬ cal limits stated is generally preferred. Also, in this description and claims, except where the context implies otherwise, the term "aluminum" is to be understood to in- elude all the alloys of aluminum that contain at least 45 % by weight of aluminum. Summary of the Invention

One major embodiment of this invention is an aqueous cleaning solution that comprises, preferably consists es¬ sentially of, or more preferably consists of water and: (A) from 0.3 to 7, preferably from 0.45 to 2.0, more pref¬ erably from 0.60 to 1.50, parts by weight of an alka¬ line phosphate component selected from the group con¬ sisting of the water soluble salts of phosphoric and condensed phosphoric acids and mixtures thereof; (B) from 0.1 to 4, preferably from 0.20 to 1.5, more pref¬ erably from 0.20 to 0.80, parts by weight of an alka¬ line borate component selected from the group consist¬ ing of the water soluble salts of boric and condensed boric acids and mixtures thereof; (C) from 0.2 to 10, preferably from 0.45 to 3.0, more preferably from 0.60 to 2.0, parts by weight of a com¬ ponent of nonionic surfactant having an average hydro- phile-lipophile-balance ("HLB") value within the range from 7 - 13, more preferably within the range from 9 - 11.5;

(D) from 0.2 to 10, preferably from 0.4 to 2.0, more pref¬ erably from 0.50 to 1.5, parts by weight of a compon¬ ent of anionic surfactant;

(E) from 0.25 to 15, preferably from 0.4 to 3.0, more preferably from 0.50 to 2.0, parts by weight of a com¬ ponent of organic solvent selected from the group con¬ sisting of organic compounds that are in the liquid phase and are completely miscible with water at 25* C and mixtures thereof; and (F) from 0.001 to 0.020, preferably from 0.001 to 0.015, more preferably from 0.0010 to 0.010, parts by weight of a component of organic corrosion inhibitor selected from the group consisting of organic molecules that are (i) soluble in water to the extent of at least 0.0001 % by weight at 25^* C and (ii) contain in each molecule at least one atom selected from the group consisting of nitrogen atoms chemically bonded to not more than three other atoms, phosphorus atoms chemi¬ cally bonded to not more than three other atoms, and sulfur atoms chemically bonded to not more than two other atoms; and, optionally, (G) up to 0.30, preferably from 0.030 to 0.15, more pref¬ erably from 0.040 to 0.10, parts by weight of an al¬ kaline hydroxide component selected from the group consisting of the water soluble hydroxides of the al¬ kali and alkaline earth metals and mixtures thereof; and, optionally,

(H) up to 3.0, preferably from 0.4 to 2.0, more preferably from 0.5 to 1.3, parts by weight of an alkaline sili¬ cate component selected from the group consisting of the water soluble and water dispersible silicates and condensed silicates and mixtures thereof.

In the description of the invention herein, the term "parts by weight" is referred to a total of 100 parts by weight in the total solution or other mixture so described, unless some explicit statement to the contrary is made herein; the term "solution" includes true solutions and dispersions that are sufficiently stable to avoid visually detectable phase stratification for at least twenty-four hours at 25' C; the terms "water soluble" and "water dis¬ persible", when not otherwise explicitly quantified, mean soluble or dispersible respectively to the extent of at least 1 % by weight in conventionally deionized water, to form a mixture that is sufficiently stable to avoid visu¬ ally detectable phase stratification for at least twenty- four hours at 25* C; the term "salts of ... acids" includes salts of hypothetical acids that correspond to the anions in the salts, as well as salts of acids that can be isolat¬ ed as free acids; and the term "anionic surfactant" in¬ cludes not only those surfactants that contain surface active anions before they are added to the aqueous solu- tions, but also surfactants such as the alkyl acid anhy¬ drides that form surface active anions when added to a bas¬ ic aqueous solution (as a result of rapid hydrolysis and at least partial neutralization of the resulting organic acid, in the case of alkyl acid anhydrides.) Otherwise, (i) the descriptions of particular chemical species refer predomi¬ nantly to the form in which the materials so described are added when preparing the solutions, and are not be under¬ stood as precluding chemical reactions among the species added which may lead to the presence in the solutions of chemical species other than those specifically added; and (ii) descriptions of a component as selected from a group of certain constituents is to be understood as implying that the component may be a mixture of materials, each of which is within the group from which the constituents may be selected, unless there is some express statement to the contrary in a particular instance. All of the description above applies to compositions as actually used in cleaning metals. Another embodiment of the invention is a concentrate, which can be diluted with water to produce a working composition as defined above. Concentrates preferably contain from 3 to 20 times the con- centrations of each ingredient or component, except water, as described above for working solutions.

Another embodiment of the invention is a process of cleaning a soiled metal surface by contacting the soiled metal surface with an aqueous cleaning solution according to the invention for a sufficient time to transfer the soil originally on the metal surface to a dispersed state within the aqueous cleaning solution, as modified by the presence of the soil thus transferred. Preferably, the metal sur¬ face thus cleaned is subsequently removed from contact with the cleaning solution and rinsed at least once with water, with at least the last such rinse most preferably being with deionized, distilled, or otherwise purified water, before further processing or use.

Description of Preferred Embodiments With increasing preference in the order given, at least 55, 80, or 95 % by weight of the alkaline phosphate component (A) as designated above is selected from alkali metal salts of condensed phosphoric acids, i.e., those con¬ taining at least two, more preferably exactly two, phos¬ phorus atoms per molecule. The single most preferred con¬ stituent for this component is tetrapotassium pyrophos- phate.

With increasing preference in the order given, at least 50, 70, or 95 % by weight of the alkaline borate com¬ ponent (B) as designated above is selected from alkali met¬ al, more preferably potassium and/or, most preferably, sod- ium salts of tetraboric acid.

With increasing preference in the order given, at least 60, 80, or 95 % by weight of the nonionic surfactant component (C) as designated above is selected from mole¬ cules that could be made by condensing ethylene oxide with monofunctional alcohols that contain from 9 to 15 carbon atoms per molecule, and preferably, no other atoms than carbon, hydrogen, nitrogen, and a single hydroxyl oxygen in the alcohol molecule. Independently, it is preferred that at least 20 %, or more preferably at least 35 %, by weight of this component be selected from each of the two groups consisting of (i) surfactants with an HLB value of 7.0 -

9.0 and (ii) surfactants with an HLB value of 10.2 - 12.5.

With increasing preference in the order given, at least 60, 70, or 82 % by weight of the anionic surfactant component (D) as designated above is selected from mole¬ cules that are alkali metal salts of partial esters of a phosphoric acid with at least one organic alcohol.

With increasing preference in the order given, at least 30, 55, 75, or 95 % by weight of the organic solvent component (E) as designated above is selected from mole¬ cules that contain (i) at least one ether bonded oxygen atom, (ii) at least one hydroxyl bonded oxygen atom, (iii) not more than 11, more preferably from 4 to 9, still more preferably from 6 to 8, carbon atoms, and, preferably (iv) no other atoms except those explicitly recited above and hydrogen atoms. The two most preferred single materials for component (E) are the normal butyl ethers of ethylene glycol and diethylene glycol.

With increasing preference in the order given, at least 30, 55, 75, or 95 % by weight of the organic corro¬ sion inhibitor component (F) as designated above is select- ed from molecules that (i) contain at least one nitrogen atom that is bound to exactly three other atoms exclusive of hydrogen atoms by single bonds and (ii) contain from 6 to 15 carbon atoms. Still more preferably, the inhibitor component (F) is selected partially or wholly from mole- cules containing a triazole ring structure.

With increasing preference in the order given, at least 60, 80, or 95 % by weight of the alkaline hydroxide component (G) as designated above is selected from the group consisting of potassium and sodium hydroxides and mixtures thereof.

With increasing preference in the order given, at least 30, 55, 75, or 95 % by weight of the alkaline sili¬ cate component (H) as designated above is selected from the group consisting of aqueous liquid sodium and/or, more preferably, potassium, soluble silicate preparations that have (i) a ratio by weight of alkali metal oxide equivalent to silicon dioxide equivalent in the range from 1:1 to 1:6, or more preferably in the range from 1.0:2.0 to 1.0:3.0, and (ii) a pH of at least 10.0, or more preferably at least 11.0.

A cleaning solution composition according to this in¬ vention preferably has a pH value within the range from 7.5 to 12, more preferably from 8.5 to 11.5, or still more preferably from 9.4 to 10.9. Also, independently, a clean- ing solution according to this invention preferably has a total alkalinity value within the range from 0.5 to 35, more preferably from 0.8 to 11, or still more preferably from 1.0 to 7.0, points. The points of free alkalinity are measured by titrating a^" 5 milliliter sample of the solution with 0.1 N strong acid, using a bromocresol green indicat¬ or. The number of milliliters of acid required to reach the end point is the number of points of total alkalinity for the sample.

For stability in storage, it is preferable to prepare working cleaning solutions, or concentrates thereof, that are free from optional components (G) and (H) as described above. A separate composition comprising optional compon¬ ents (G) and (H) , and generally also comprising necessary component (E) in about the same percentage by weight as is desired in the final composition, is also stable in storage for a considerable time. The adjunct composition contain- ing the optional components can then conveniently be mixed with the normal solution containing all the necessary com¬ ponents, and if needed or desired, with additional water, shortly before use, when a silicated cleaning solution is desired. A silicated cleaning solution is generally pre- ferred for cleaning galvanized steel and most aluminum alloys, to avoid undesired etching of the surface to be cleaned.

A group of preferred concentrate compositions accord¬ ing to the invention contain, in % by weight of active in- gredients, exclusive of water, from 6.0 - 6.6 % of compon¬ ent (A), from 3.5 - 5.0 % of component (B) , from 6.0 - 8.0 % of component (C) , from 5.0 - 6.0 % of component (D) , from 5.0 - 9.0 % of component (E) , and from 0.012 - 0.05 % of component (F) , all the components identified by letter hav- ing the same meanings as described above for working compo¬ sitions, and water to form the remainder of the concen¬ trate. A particularly preferred concentrate composition according to the invention contains the following amounts (in % by weight of active ingredients, exclusive of water) of the following components: 6.0 - 6.6 % Of K₄P₂0₇, 3.5 - 5.0 % Of Na₂B₄0₇,

6.0 - 8.0 % of nonionic surfactant molecules that could be made by condensing ethylene oxide with monofunctional alcohols that contain from 9 to 13 carbon atoms per molecule and contain no other atoms than carbon, hy¬ drogen, nitrogen, and a single hydroxyl oxygen in the alcohol molecule, with at least one quarter of the total weight being selected from surfactants with an HLB value of 7.0 - 9.0 and at least one quarter of the total weight being selected from surfactants with an HLB value of 10.2 - 12.5,

3.5 - 5.0 % of hydrotropic phosphate anionic surfactant,

0.0 - 1.5 % of nonenyl succinic anhydride,

0.0 - 1.0 % of ethoxylated anionic surfactant,

5.0 - 9.0 % of monobutyl ether of diethylene glycol, 0.012 - 0.05 % of mixed naphthyl and butyl triazoles, and water to form the remainder of the concentrate. A particularly preferred adjunct silicating composition ac¬ cording to the invention contains 0.4 - 0.5 % by weight of potassium hydroxide, 5.0 - 6.0 % by weight of soluble po- tassium silicate, and 9.0 - 11.0 % by weight of the mono- butyl ether of diethylene glycol.

Contact between the surface to be cleaned and a cleaning solution according to the invention may be achieved by any convenient method, such as immersing the surface in a container of the cleaning solution, spraying the cleaning solution on the surface to be cleaned, and the like, all as generally known per se in the art. Contact by immersion is preferred. The compositions according to the invention are preferably used for cleaning at temperatures within the range from 30 to 80, more preferably from 40 to 70, or still more preferably from 50 to 60, * c. The time of immersion contact between the surfaces to be cleaned and the compositions according to the invention preferably is from 1 to 30, more preferably from 5 to 20 sec, or still more preferably from 10 to 15, minutes (hereinafter abbrev¬ iated "min") . Within the ranges given, shorter times are usually sufficient to remove light oils, while longer times are needed to remove heavy greases.

The cleaning solutions and processes according to this invention are generally effective with any common struc¬ tural metal that is desired to be cleaned, but they are especially valuable for aluminum and its common commercial alloys, magnesium ana its common commercial a oys, ow alloy steel, cadmium plated steel, titanium and its common commercial alloys, nickel alloys and high nickel content ferrous alloys, and alloy-galvanized surfaces. After being cleaned according to this invention, as described in its essential features above, the workpieces may then be subjected to further surface treatments such as conversion coating, anodization, painting, and the like, as known per se in the art, in a process sequence that is within the scope of this invention.

The practice of the invention may be further appreci¬ ated from the following non-limiting examples.

Examples Example 1 A suitable aqueous cleaning solution concentrate ac¬ cording to the invention containing only the necessary com¬ ponents (A) - (F) as described above was prepared by mixing the mixing the following ingredients in the order given (except that about 10 % of the total amount of water was retained for addition after all the other ingredients) :

Ingredient Amount in Parts by

Weight Tap water 589.5

Tetrapotassium pyrophosphate (60 % aqueous solution) 110.0

Sodium tetraborate pentahydrate (Na₂B₄0₇«5H₂0) 50.0

Anionic surfactant chosen from TRITON™ H-55, TRITON™ H-66, TRITON™ QS-44, and mixtures 70.0 of any two or more of these

Nonenyl succinic anhydride (anionic surfactant) 15.0

Nonionic surfactant chosen from TRITON™ DF-12,

TRITON™ DF-16, TRITON™ DF-18, MAKON™ NF-12, 10.0 and mixtures of any two or more of these

TRITON™ DF-20 anionic surfactant 10.0

Nonionic surfactant chosen from ANTAROX™ BL-225, ANTAROX™ BL-330, ANTAROX™ BL-344, ANTAROX™ LF-330, PLURAFAC™ RA-40, SURFONIC™ LF-17, and ° mixtures of any two or more of these Nonionic surfactant chosen from GENAPOL™ 24-L-3,

NEODOL™ 91-2.5, NEODOL™ 25-3, NEODOL™ 1-5, -_{n n} TERGITOL™ 15-S-3, TERGITOL™ TMN-3, and ^JU*U mixtures of any two or more of these

Nonionic surfactant chosen from GENAPOL™ 24-L-45 NEODOL™ 25-7, NEODOL™ 23-6.5, NEODOL™ 91-6, TERGITOL™ 15-S-5, TERGITOL™ TMN-6, and 10.0 mixtures of any two or more of these

Monobutyl ether of diethylene glycol 90.0 Corrosion inhibitor chosen from COBRATEC™ 700,

COBRATEC™ 725, and mixtures of these °^*5,

TRITON™ H-55, H-66, and QS-44 are described by their supplier as "phosphate surfactant, potassium salt" for both

H-55 and H-66 and as "phosphate surfactant in free acid form" for QS-44; TRITON™ DF-12, DF-16, and DF-18 are de¬ scribed by their supplier as "modified polyethoxylated straight chain alcohol; HLB: 10.6", "modified polyethoxyl¬ ated straight chain alcohol; HLB: 11.6", and "modified pol¬ yethoxylated alcohol; HLB: 11.3" respectively; TRITON™ DF- 20 is described by its supplier as "anionic modified ethox- ylate"; all the TRITON™ products are commercially available from Union Carbide Corp. MAKON™ NF-12 is described by its supplier, Stepan Co., as "polyalkoxylated aliphatic base". ANTAROX™ BL-225, BL-330, BL-344, and LF-330 are all com- mercially available from Rhδne-Poulenc Corp. and are all described by their supplier as "nonionic modified linear aliphatic polyethers". TERGITOL™ 15-S-3, 15-S-5, TMN-3, and TMN-6 are commercially available from Union Carbide Corp. and are described by their supplier as "C,, - c₁₅ secondary alcohol ethoxylates" for 15-S-3 and 15-S-5, with HLB values of 8.0 and 10.5 respectively and as "ethoxylated trimethyl nonanol" for TMN-3 and TMN-6, with HLB values of 8.3 and 11.7 respectively. NEODOL™ 91-2.5, 91-6, 25-3, 25- 7, and 23-6.5 surfactants are commercially available from Shell Chemical Co. and are described by their supplier as "C₉ - C linear primary alcohol ethoxylate" for 91-2.5 and 91-6, with an HLB value of 8.1 for 91-2.5 and of 12.5 for 91-6; as "C₁₂ - C₁₅ linear primary alcohol ethoxylate" for 25-3 and 25-7, with an HLB value of 7.9 for 25-3 and of 12.2 for 25-7; as "C₁₂ - C₁₃ linear primary alcohol ethoxyl- ate" with an HLB value of 12.0 for 23-6.5; and as "C,, lin¬ ear primary alcohol ethoxylate" with an HLB value of 11.2 for 1-5. COBRATEC™ 700 and 725 are commercially available from PMC, Inc.; the compositions have not been disclosed by the manufacturer, except to state that 725 is a solution of the sodium salt of 700, but the latter is believed to be a triazole or a mixture of triazoles. GENAPOL™ 24-L-3 and 24-L-45 are available from Hoechst-Celanese Corp and are described by their supplier as C₁₂ - c_u synthetic linear alcohol ethoxylates" with an HLB value of 8.0 for 24-L-3 and of 11.8 for 24-L-45. PLURAFAC™ RA-40 is commercially available from BASF Corp. and is described by its supplier as "nonionic modified oxyethylated straight chain alcohol; HLB: 7.0". SURFONIC™ LF-17 is commercially available from Texaco Chemical Co. and is described by its supplier as "nonionic alkyl polyoxyalkylene ether; HLB: 12.2." Example 2

A suitable aqueous cleaning solution concentrate ac¬ cording to the invention containing only the necessary com- ponents (A) - (F) as described above was prepared by mixing the following ingredients in the order given (except that about 10 % of the total amount of water was retained for addition after all the other ingredients) :

Ingredient Amount in Parts by Weight

Tap water 634.5

Tetrapotassium pyrophosphate .__ _

(60 % aqueous solution)

Sodium tetraborate pentahydrate (Na₂B₄0₇*5H₂0) 35.0

Nonionic surfactant chosen from GENAPOL™ 24-L-3, NEODOL™ 91-2.5, NEODOL™ 25-3, NEODOL™ 1-5, TERGITOL™ 15-S-3, TERGITOL™ TMN-3, and ^4U*U mixtures of any two or more of these

Nonionic surfactant chosen from GENAPOL™ 24-L-45, NEODOL™ 25-7, NEODOL™ 23-6.5, NEODOL™ 91-6, TERGITOL™ 15-S-5, TERGITOL™ TMN-6, and ^4U,U mixtures of any two or more of these

Monobutyl ether of diethylene glycol 90.0 Corrosion inhibitor chosen from COBRATEC™ 700, COBRATEC™ 725, and mixtures of these 0.5.

The trademarks have the same meaning as in Example 1. Adjunct Example 3

A silicating additive concentrate composition, suit¬ able for mixing with a cleaning solution containing only the necessary components according to the invention, was prepared by mixing the following ingredients in the order given (except that about 10 % of the total amount of water was retained for addition after all the other ingredients) :

Ingredient Amount in Parts by Weight

Tap water 690.0

Potassium waterglass solution containing 20.8 % by weight Si0₂ and 8. 3 % by weight K_jO 200.0

45 % by weight aqueous potassium hydroxide solution 10.0

Monobutyl ether of diethylene glycol 100.0

The invention claimed is:

Claims

1. A liquid aqueous concentrate cleaning composition consisting essentially of water and:

(A) from about 6 to about 6.6 % by weight of an alkaline phosphate component selected from the group consisting of the water soluble salts of phosphoric and condensed phosphoric acids and mixtures thereof;

(B) from about 2.4 to about 3.5 % by weight of an alkaline borate component selected from the group consisting of the water soluble salts of boric and condensed boric acids and mixtures thereof;

(C) from about 6 to about 8 % by weight of a component of nonionic surfactant having an average hydrophile-lipo- phile-balance ("HLB") value within the range from about 7 to about 13;

(D) from about 5.0 to about 6.0 % by weight of a component of anionic surfactant;

(E) from about 5.0 to about 9.0 % by weight of a component of organic solvent selected from the group consisting of organic compounds that are in the liquid phase and are completely miscible with water at 25* C and mix¬ tures thereof; and

(F) from about 0.012 to about 0.05 % by weight of a com¬ ponent of organic corrosion inhibitor selected from the group consisting of organic molecules that are (i) soluble in water to the extent of at least 0.001 % by weight at 25* C and (ii) contain in each molecule at least one atom selected from the group consisting of nitrogen atoms chemically bonded to not more than three other atoms, phosphorus atoms chemically bonded to not more than three other atoms, and sulfur atoms chemically bonded to not more than two other atoms.

2. A composition according to claim 1, wherein at least about 80 % by weight of component (C) is selected from mol¬ ecules that could be made by condensing ethylene oxide with monofunctional alcohols, said alcohols containing from 9 to 15 carbon atoms per molecule and no other atoms than car¬ bon, hydrogen, nitrogen, and a single hydroxyl oxygen; at least about 60 % of component (D) is selected from mole¬ cules of alkali metal salts of partial esters of a phos¬ phoric acid with at least one alcohol; and at least 55 % by weight of component (F) is selected from molecules that (i) contain at least one nitrogen atoms that is bonded to ex¬ actly three other atoms exclusive of hydrogen atoms by single chemical bonds and (ii) contain from 6 to 15 carbon atoms.

3. A composition according to claim 2, wherein at least 95 % of component (A) is tetrapotassium pyrophosphate, at least 70 % of component (B) is sodium tetraborate, at least about 20 % by weight of component (C) is selected from sur¬ factants with an HLB value in the range from about 7.0 to about 9.0, at least about 20 % by weight of component (C) is selected from surfactants with an HLB value in the range from about 10.2 to about 12.5, at least about 75 % by weight of component (E) is selected from the monobutyl eth¬ ers of ethylene glycol and diethylene glycol or a mixture thereof, and at least about 75 % of component (F) is se¬ lected from molecules containing a triazole ring structure.

4. An adjunct silicating composition, consisting essenti¬ ally of water and:

(G) from about 0.4 to about 0.5 % by weight of potassium hydroxide;

(H) from about 5.0 to about 6.0 % by weight of soluble po¬ tassium silicate having a ratio by weight of potassium oxide equivalent to silicon dioxide equivalent in the range from 1.0: 2.0 to 1.0:3.0; and (E') from about 9.0 to about 11.0 % by weight of the mono- butyl ether of diethylene glycol. 5. An aqueous alkaline cleaning composition having a pH value in the range from about 7.5 to about 12 and a total alkalinity value in the range from about 0.

5 to about 35 and consisting essentially of water and: (A) from about 0.3 to about 7 % of an alkaline phosphate component selected from the group consisting of the water soluble salts of phosphoric and condensed phos¬ phoric acids and mixtures thereof;

(B) from about 0.1 to about 4 % of an alkaline borate com- ponent selected from the group consisting of the water soluble salts of boric and condensed boric acids and mixtures thereof;

(C) from about 0.2 to about 10 % of a component of nonion¬ ic surfactant having an average HLB value within the range from about 7 to about 13;

(D) from about 0.2 to about 10 % of a component of anionic surfactant;

(E) from about 0.25 to about 15 % of a component of organ¬ ic solvent selected from the group consisting of or- ganic compounds that are in the liquid phase and are completely miscible with water at 25* C and mixtures thereof; and

(F) from about 0.001 to about 0.020 % of a component of organic corrosion inhibitor selected from the group consisting of organic molecules that are (i) soluble in water to the extent of at least 0.0001 % by weight at 25* C and (ii) contain in each molecule at least one atom selected from the group consisting of nitro¬ gen atoms chemically bonded to not more than three other atoms, phosphorus atoms chemically bonded to not more than three other atoms, and sulfur atoms chemi¬ cally bonded to not more than two other atoms; and, optionally,

(G) up to about 0.30 % of an alkaline hydroxide component selected from the group consisting of the water solu¬ ble hydroxides of the alkali and alkaline earth metals and mixtures thereof; and, optionally, (H) up to about 3.0 % of an alkaline silicate component selected from the group consisting of the water sol¬ uble and water dispersible silicates and condensed silicates and mixtures thereof.

6. A process comprising cleaning a soiled metal surface by contacting the metal surface for a time in the range from about 1 to about 30 min with a composition according to claim 5 maintained at temperature within the range from about 30 to about 80 ^* C.

7. A composition according to claim 5, wherein at least about 80 % by weight of component (C) is selected from molecules that could be made by condensing ethylene oxide with monofunctional alcohols, said alcohols containing from 9 to 15 carbon atoms per molecule and no other atoms than carbon, hydrogen, nitrogen, and a single hydroxyl oxygen; at least about 60 % of component (D) is selected from mole¬ cules of alkali metal salts of partial esters of a phos¬ phoric acid with at least one alcohol; and at least 55 % by weight of component (F) is selected from molecules that (i) contain at least one nitrogen atoms that is bonded to ex¬ actly three other atoms exclusive of hydrogen atoms by single chemical bonds and (ii) contains from 6 to 15 carbon atoms.

8. A process comprising cleaning a soiled metal surface by contacting the metal surface for a time in the range from about 1 to about 30 min with a composition according to claim 7 maintained at temperature within the range from about 30 to about 80 * C.

9. A composition according to claim 7, wherein at least 95 % of component (A) is tetrapotassium pyrophosphate, at least 70 % of component (B) is sodium tetraborate, at least about 20 % by weight of component (C) is selected from sur- factants with an HLB value in the range from about 7.0 to about 9.0, at least about 20 % by weight of component (C) is selected from surfactants with an HLB value in the range from about 10.2 to about 12.5, at least about 75 % by weight of component (E) is selected from the monobutyl eth- ers of ethylene glycol and diethylene glycol or a mixture thereof, and at least about 75 % of component (F) is se¬ lected from molecules containing a triazole ring structure.

10. A process comprising cleaning a soiled metal surface by contacting the metal surface for a time in the range from about 1 to about 30 min with a composition according to claim 9 maintained at temperature within the range from about 30 to about 80 * C.

11. A composition according to claim 5, wherein the pH value is in the range from about 8.5 to about 11.5, the total alkalinity value is in the range from about 0.8 to about 11, the amount of component (A) is from about 0.45 to about 2.0 % by weight, the amount of component (B) is in the range from about 0.20 to about 1.5 % by weight, the amount of component (C) is from about 0.45 to about 3.0 % by weight, the amount of component (D) is from about 0.4 to about 2.0 % by weight, the amount of component (E) is from about 0.4 to about 3.0 % by weight, the amount of component (F) is from about 0.001 to about 0.015 % by weight, the amount of component (G) is from about 0.030 to about 0.15 % by weight, and the amount of component (H) is from about 0.4 to about 2.0 % by weight.

12. A process comprising cleaning a soiled metal surface by contacting the metal surface for a time in the range from about 1 to about 30 min with a composition according to claim 11 maintained at temperature within the range from about 30 to about 80 * C.

13. A composition according to claim 5, wherein the pH value is in the range from about 9.4 to about 10.9, the total alkalinity value is in the range from about 1.0 to about 7.0, the amount of component (A) is from about 0.60 to about 1.5 % by weight, the amount of component (B) is in the range from about 0.2 to about 0.8 % by weight, the amount of component (C) is from about 0.6 to about 2.0 % by weight, the amount of component (D) is from about 0.5 to about 1.5 % by weight, the amount of component (E) is from about 0.5 to about 2.0 % by weight, the amount of component (F) is from about 0.001 to about 0.010 % by weight, the amount of component (G) is from about 0.040 to about 0.100 % by weight, and the amount of component (H) is from about 0.5 to about 1.3 % by weight.

14. A process comprising cleaning a soiled metal surface by contacting the metal surface for a time in the range from about 1 to about 30 min with a composition according to claim 13 maintained at temperature within the range from about 30 to about 80 * C.

15. A composition according to claim 14, wherein at least about 80 % by weight of component (C) is selected from mol¬ ecules that could be made by condensing ethylene oxide with monofunctional alcohols, said alcohols containing from 9 to 15 carbon atoms per molecule and no other atoms than car- bon, hydrogen, nitrogen, and a single hydroxyl oxygen; at least about 60 % of component (D) is selected from mole¬ cules of alkali metal salts of partial esters of a phos¬ phoric acid with at least one alcohol; and at least 55 % by weight of component (F) is selected from molecules that (i) contain at least one nitrogen atoms that is bonded to ex¬ actly three other atoms exclusive of hydrogen atoms by single chemical bonds and (ii) contains from 6 to 15 carbon atoms.

16. A process comprising cleaning a soiled metal surface by contacting the metal surface for a time in the range from about 1 to about 30 min with a composition according to claim 15 maintained at temperature within the range from about 30 to about 80 ' C.

17. A composition according to claim 15, wherein at least 95 % of component (A) is tetrapotassiu pyrophosphate, at least 70 % of component (B) is sodium tetraborate, at least about 20 % by weight of component (C) is selected from sur- factants with an HLB value in the range from about 7.0 to about 9.0, at least about 20 % by weight of component (C) is selected from surfactants with an HLB value in the range from about 10.2 to about 12.5, the average HLB value of component (C) is in the range from about 9 - 11.5, at least about 75 % by weight of component (E) is selected from the monobutyl ethers of ethylene glycol and diethylene glycol or a mixture thereof, and at least about 75 % of component (F) is selected from molecules containing a triazole ring structure.

18. A process comprising cleaning a soiled metal surface by contacting the metal surface for a time in the range from about 1 to about 30 min with a composition according to claim 17 maintained at temperature within the range from about 30 to about 80 * C.

19. A process according to claim 18, wherein the metal surface is contacted for a time in the range from about 5 to about 20 min at temperature in the range from about 40 to about 70 " C.

20. A process according to claim 19, wherein the metal surface is contacted for a time in the range from about 10 to about 15 min at temperature in the range from about 50 to about 60 ' C.