EP0151114B1

EP0151114B1 - Acid based variable viscosity compositions such as corrosion and grease removers and polishers

Info

Publication number: EP0151114B1
Application number: EP19830902583
Authority: EP
Inventors: Peter F. Dr. Lott; Reiner Jargosch
Original assignee: Individual
Current assignee: Jargosch Reiner; Lott Peter F Dr
Priority date: 1983-07-06
Filing date: 1983-07-06
Publication date: 1990-04-04
Also published as: DE3381414D1; JPS60501817A; WO1985000379A1; EP0151114A1; EP0151114A4

Abstract

An improved, highly penetrating rust remover and/or degreaser composition for metallic surfaces, which is chemically inhibited to substantially prevent oxidation-reduction reactions with a metal substrate and limit the action of the composition to a chemical attack on corrosion. The composition is preferably a single phase dispersion and includes respective quantities of an acid such as hydrochloric acid and phosphoric acid, an organic compound containing a nitrogen, oxygen or sulfur atom such as N-(2-hydroxyethyl) oxazolidine, an alcohol or other organic solvent for grease removal, water and one or more emulsifiers (e.g., a derivative of hydrogenated tallow) for stabilizing and lowering the surface tension of the resultant composition. The compositions may be formulated as liquids or with a viscosity control agent such as a polylmer of vinyl pyrrolidone to give a paste-like consistency permitting easy use thereof on vertical surfaces. In other forms, the compositions hereof may include a mild abrasive such as activated silica gel.

Description

Background of the Invention

1. Field of the Invention

The present invention is concerned with improved, acid-based corrosion, grease removal and polishing compositions for treating metallic surfaces and objects. More particularly, it is concerned with such compositions which are compounded so as to substantially prevent oxidation-reduction reactions that would normally take place at a metallic surface, and allow only acid attack of the oxides on the metal. In preferred forms, the compositions hereof may include, in addition to polyvinyl pyrrolidone as a viscosity control agent and inhibitor, a derivative of hydrogenated tallow as an emulsifier, and an N-substituted oxazolidine as an acid inhibitor.

2. Description of the Prior Art

Compositions for removing corrosion (metal oxides) from metallic surfaces and objects have long been available. Generally speaking, such materials are acid based, i.e., they rely upon an acidic attack in order to remove corrosion.
A persistent problem encountered in connection with prior corrosion removal compositions and polishes stems from the fact that oxidation reduction reactions can occur between the compositions and the underlying metal surfaces to be cleaned and decorroded. Hence, while many of these prior compositions were effective in corrosion removal and/or polishing, they often were prone to attack the metal substrate and leave the same pitted and unattractive.
Another problem with such prior compositions stems from the fact that they are ineffective as grease removers. Accordingly, if the metallic surfaces desired to be decorroded had substantial amounts of fatty organic (oil) films thereon, the effectiveness of the compositions was reduced, and the acidic and aqueous; components thereof hindered in removal of corrosion.
Furthermore, such solutions were of uncontrolled viscosity, either being too viscous to prevent application by spray or brush, or too low in viscosity to cling on vertical surfaces.

Summary of the Invention

The present invention overcomes the problems noted above, and provides greatly improved, flowable, aqueous, highly penetrating compositions of acidic pH which are effective for polishing and removal of corrosion from metallic surfaces, and also to degrease the same.
According to the invention, there is provided a metal cleaning composition comprising a flowable system of water, from 5 to 37% by weight of an acid selected from the group consisting of hydrochloric, sulfuric, phosphoric, nitric and mixtures thereof, from 0.5 to 5% by weight of polyvinylpyrrolidone, from 0.01 to 15% by weight of an emulsifier, from 0.01 to 20% by weight of a base metal attack inhibitor compound selected from the group consisting of N-substituted oxazolidines, the p-alkyl benzyl pyridine chlorides, phenylthiourea, 2-mercaptobenzothiazole, diortho-tolyl-thiourea, pyridine, quinoline, decylamine, the dibensyl sulfoxides, 2-butyne-1, 4-diol, 1-hexyne-3-ol, 4-ethyl-1-octyne-3-₀I, decylamine, soyaamine, octadecylamine, trimethylsoyammonium chloride, trimethyloctadecylammonium chloride, trimethyldodecylammonium chloride, trimethyltallowammonium chloride, N-coco-1, 3-diaminopropane, the tetraalkylammonium bromides having an alkyl group with at least 10 carbon atoms therein, the mono-, di-, and tributylamines, hexamethylenediamine, 2-(bis)2-hydroxyethyl(amino)-1,3-propane-diol, 2-(bis)2-hydroxyethyl(amino)-methanediamine, 1,6,8-triaza-4, 10-dioxabicyclo(5,5,O)dodecane, and mixtures thereof, and 0-20% by weight of an alcohol, having an alkyl group containing from 1 to 10 carbon atoms.
The base metal attack inhibitor preferably is present in an amount from 0.5 to 5% by weight.
The alcohol component is most preferably 1-propanol, but other alcohols could also be employed. These alcohols have an alkyl group with from 1 to 10 carbon atoms, inclusive. The alcohol should be used at a level of up to 20% by weight, and most preferably at a level of about 1 to 8% by weight.
The water is preferably present at a level of from 30% to 90% by weight, and most advantageously at a level of from about 50% to 80% by weight.
The most preferred emulsifiers for use in the invention are selected from the group consisting of the derivatives of hydrogenated tallow (e.g., N, N', N'-tris (2-hydroxyethyl)-N-tallow-1, 3-diamino-propane or amine acetate hydrogenated tallow), polyoxyethylene ethers, polyoxyethylene ester alcohols, polyoxyethylene esters of mixed fatty and resin acids and mixtures thereof, although other specific types referred to hereinafter also have utility. The total amount of emulsifier present in the composition should be from about 0.01 % to 15% by weight, and more preferably from about .5% to 5% by weight.
A viscosity control agent (thickener) is used in the compositions hereof to give variations in viscosity. Such viscosity control has heretofore proved to be difficult or impossible to obtain in acidic compositions, inasmuch as most conventional thickeners tend to flocculate at low pH. The control agent of the invention isopolyvinylpyrrolidone at a level of from 0.5% to 5% by weight.
A synergistic effect is observed by the use of the mixture of polyvinyl pyrrolidone, Ethoduomeen T/13, (Registered Trade Mark) and N-(2-hydroxyethyl)-oxazolidine as a corrosion inhibitor in preventing base metal attack, inasmuch as the attack with the preferred mixture is less than that of any of the individual corrosion inhibitors.
In further forms of the invention, a mild abrasive such as activated silica gel (at a level of up to about 10% by weight) can be employed. Perfumes and coloring agents can be added as desired. In addition the system can be modified for corrosion removal on metal surfaces having a heavy grease or oil coating by preparing a two-phase emulsified system by the addition of toluene or related organic solvents.

Brief Description of the Drawing

The single feature is a graphical representation depicting the extent of base metal attack when using a commercially available corrosion remover, 10% HCI and the preferred corrosion removing composition of the invention.

Description of the Preferred Embodiments

The most preferred rust removal compositions in accordance with the present invention contain commercial hydrochloric acid, commercial phosphoric acid, 1-propanol, N-(2 hydroxyethyl) oxazolidine, water, a thickening agent, and N,N', N'-tris(2-hydroxyethyl)-N-tallow-1, 3-diaminopropane as an emulsifier. The following table sets forth the single most preferred rust removal composition, as well as ranges of use of the above indentified components.
The oxazolidine base metal inhibitor component of Table I is prepared by slowly adding, with mixing, 435.7 grams of formaldehyde to a beaker containing 564.3 grams of diethanolamine. After all formaldehyde is added, the mixture should be stirred for an additional hour.
In other contexts, a base metal inhibitor component can be produced as the reaction product of a lower aldehyde (i.e., containing from about 1-4 carbon atoms) and an alkanolamine (containing one or more alkyl group each having from about 2-8 carbon atoms).
In formulating the preferred composition of Table I, the beaker containing 590 grams of water is provided. Ten grams of the Ethoduomeen T/13 hydrogenated tallow emulsifier, 270 grams hydrochloric acid, 40 grams phosphoric acid, and 50 grams of I-propanol are all added to the beaker, with continual mixing. The mixture is then heated to 50°C.; and 30 grams polyvinylpyrrolidine is slowly added thereto. Mixing is continued until all of the polymer has dissolved.
The drawing graphically illustrates the inhibition against base metal attack provided with the preferred composition of Table I. Specifically, a commercially available corrosion remover sold under the designation "Naval Jelly" was tested, along with a solution of 10% hydrochloric acid, and the preferred composition thereof. In all cases, testing conditions were identical, and the extent of attack on a base metal substrate was measured. As can be seen, the extent of such attack is very high with the Naval Jelly and hydrochloric acid, but is significantly lower with the preferred inhibitor composition of the invention.
In the case of a cleaner/polish for brass and copper, the most preferred compositions, and the ranges of use for components, are set forth below:
In preparative procedures all of the components save the polyvinylpyrrolidone are simply admixed as a single phase dispersion or solution, whereupon the mixture is heated to 50°C. (although such heating is optional) and the polymer is slowly added thereto with mixing to give a thickened, viscous composition.
As noted above, a number of different materials can be employed for the various components. With respect of the emulsifier(s), surfactants available from ICI Americas, Inc., Wilmington, Delaware, and Armak Chemicals Division, Chicago, Illinois, can be employed in lieu of or in addition to the preferred tallow based emulsifiers. An exemplary list of such surfactants is provided in Table III.
The compositions of the invention are effective to remove corrosion from base metallic surfaces while substantially preventing oxidation-reduction reactions with the metal itself. In addition, grease removal is enhanced by virtue of the presence of a single phase, aqueous system. Use of preferred single phase system also enhances the penetration of corrosion where the latter is present.
Representative metals which can be cleaned and/or degreased using the compositions hereof include iron and steel, bronze, brass, copper, monel, nickel, chromium, plated metals and aluminium.
A cleaner for tubes of boilers may also be provided by incorporating in the formulation a high foaming agent plus thickeners such as polyvinylpyrrolidone to improve wall adherence. This allows the corrosion remover to be circulated and foamed in place throughout the system by pumping or by an air blast. An additive such as Arlatone G may also be included as desired to help prevent surface rerusting. This type of corrosion remover is advantageous in that a small amount will cover a large surface area and does not require heating to permit the corrosion removal action to take place. Also, since the components are water soluble, removal of the corrosive remover can be performed by flushing water through the system.

Claims

1. A metal cleaning composition comprising a flowable system of water, from 5 to 37% by weight of an acid selected from the group consisting of hydrochloric, sulfuric, phosphoric, nitric and mixtures thereof, from 0.5 to 5% by weight of polyvinylpyrrolidone, from 0.01 to 15% by weight of an emulsifier, from 0.01 to 20% by weight of a base metal attack inhibitor compound selected from the group consisting of N-substituted oxazolidines, the p-alkyl benzyl pyridine chlorides, phenylthiourea, 2-mercaptobenzothiazole, diortho-tolylthiourea, pyridine, quinoline, decylamine, the dibenzyl sulfoxides, 2-butyne-1, 4-diol, 1- hexyne-3-ol, 4-ethyl-1-octyne-3-₀I, decylamine, soyaamine, octadecylamine, trimethylsoyaammonium chloride, trimethyloctadecyl-ammonium chloride, trimethyldodecylammonium chloride, trimethyltallowammonium chloride, N-coco-1, 3-diamino-propane, the tetraalkylammonium bromides having an alkyl group with at least 10 carbon atoms therein, the mono-, di-, and tributylamines, hexamethylenediamine, 2-(bis)2-hydroxyethyl(amino)-1,3-propane-diol, 2-(bis)2-hydroxyethyl(amino)-methanediamine, 1,6,8,-triaza-4, 10-dioxabicycio(5,5,0)dodecane, and mixtures thereof, and 0-20% by weight of an alcohol, having an alkyl group containing from 1 to 10 carbon atoms.

2. A composition according to claim 1, in which said emulsifier is N,N',N'-tris-(2-hydroxyethyl)-N-tallow-1,3-diaminopropane.

3. A composition according to claim 1 or 2 in which said inhibitor compound is N-(2-hydroxyethyl)oxazolidine.

4. A composition according to claim 1, in which said alcohol is 1-propanol.

5. A composition according to any preceding claim, containing from 1 to 8% of said alcohol by weight.

6. A composition according to any preceding claim, containing from 30% to 90% by weight of water.

7. A composition according to claim 6, containing from 50% to 80% by weight of water.

8. A composition according to claim 1, containing from 2 to 35% by weight of hydrochloric acid and up to 10% by weight of phosphoric acid, and in which the inhibitor compound is N-(2-hydroxyethyl)-oxazolidone and the emulsifier is N,N',N'-tris-(2-hydroxethyl)-N-tallow-1,3 diaminopropane.