DE2014883A1 - Preparations for preventing tarnishing of metal surfaces - Google Patents

Description

Miles Laboratories, Inc.
Elkhart, Indiana 465H, USA

"concerning:
Preparations for preventing tarnishing of metal surfaces

The invention relates to a means that makes tarnishing cleaner Surfaces of metals such as copper and copper-containing alloys, and which contains a mixture of (A) 'a non-ionic or anionic surface-active Substance and (B) a substance, such as a compound, the one Contains glutamate residue, a copolymer of methyl vinyl ether and maleic anhydride or a mixture of such a copolymer and benzotriazole. This remedy is generally used mixed with 's / water and the clean surface will be in the immersed in aqueous solution or brought into contact with it in some other way.

Metal objects, v / ie fittings, drills, and the like, made of copper and copper-containing alloys, often tarnish heavily after being manufactured and it is commercially desirable to remove such tarnish before the objects are shipped to the end user. The disher Eeinigungsverfahren known to remove this initial layer consisted in general, that is first treated with a detergent-containing cleaning bath to Ji'ette, oils, soap, borax and ΐ / axis to be removed, which have been used in the molding of the article. The so

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The "cleaned" object was then treated with a pickling liquor which, in the case of copper objects , generally contained sodium cyanide. Sulfuric acid was also used in the known pickling liquors. After the treatment in this pickling liquor, the object was treated with a gloss bath which, in the case of copper objects, generally contained nitric acid or a mixture of chromic acid and sodium bisulfate. The finished article then had a clean, shiny surface.

If the polishing bath contains chromic acid, it is shiny Copper surface e.g. "passivated" and runs during the subsequent Use or atmospheric influences. However, if nitric acid is used in the gloss bath the shiny copper surface is e.g. "activated" and runs during subsequent use and through atmospheric Influences easily. A similar situation exists when the well-known Bei'z baths and gloss baths are replaced by a single Cleaning agents are replaced by citric acid, a ketal I chloride and contains a ferric salt and a nonionic surfactant. This last one Medium gives a clean, shiny metal surface that is slightly activated.

It has been suggested to use berizotriazole such activated metal surfaces, such as copper surfaces, to be treated to protect them from tarnishing. However, this treatment has not been found to be completely satisfactory proven because it is difficult to achieve uniform protection with this. Even with a reasonably good coating the object can still start up in an undesirably short time.

The present invention relates to a means for preventing the fogging of metal surfaces, which is a mixture of

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((A) a nonionic or anionic surfactant Svoff and (B) a substance _t such as a compound containing a glutamate residue, a copolymer of methyl vinyl ether and maleic anhydride and / or a mixture of such a copolymer and benzotriazole. The preferred one Component (B) is the copolymer. The ingredients of this agent are preferably used in the proportion of 0.04 to 0.4 parts by weight (A) and 0.1 to 2 parts by weight (B). This agent can be used in Water., Whereby an aqueous solution is formed which contains 0.04 to 0.4 wt .-% (A) and 0.1 to 2 wt .-% (B) is the above-mentioned copolymer / benzotriazole, it is preferable that such a mixture contains 1 to 3 parts by weight of the copolymer per part by weight of benzotriazole.

The present invention also relates to a method for Use of the above described coat to create a Coating on an object to prevent it from running. The means according to the invention for preventing tarnishing can be between approx. 25 ° C to approx. 95 ° C in the case of barn doors

ani "evi!:> iu t were and preferably at a temperature of about 85 to ^c j5 C / The object to be treated is treated with a solution of the agent, for example between 30 seconds and 3 minutes, preferably between 1.5 to 3 minutes, This contact can take place by immersing the object in the solution, or the solution can be sprayed onto a metal surface, for example, or the metal surface can be brought into contact with a viscous gel or paste containing the tarnishing prevention agent.

The non-ionic or anionic surfactants which are suitable as component (A) for the present composition are known substances. Typical non-ionic surfactants Substances are N-0> -5ydr9xy.äthyl) laury.lamid, Konylphenylpolyäthylen-Glykpl-Ether, OctylDhenylpolyäthylen-

glycol ether, sorbitan monooleate, polyoxyethylene sorbitan ^: 00 9 8 Cl / I V2 3 ^ 'Uj j . _ 4 _

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tristearate, ethoxylated isomeric linear alcohols and the like. The ethoxylated isomeric linear alcohols have the general formula:

I 2'n 3
0

in which η is an integer from 9 to 13 and y is a number from 3 to 12 is. The preferred nonionic surfactant is a nonylphenyl polyethylene glycol ether Formula:

- (C ₆ H ₄ ) - 0- / ~ CH ₂ CH ₂ O_7 ~ -CH ₂ CH ₂ OH

where χ is an integer between 5 and 70. Preferably χ has a value between 5 and 40.

Typical anionic surfactants added to the Agents of the present invention are suitable are the straight-chain, saturated carboxylic acids having 8 to 24 carbon atoms, the alkali salts of these carboxylic acids, such as sodium stearate, Dodecylbenzenesulfonic acid, liatrium lauryl sulfoacetate, monoethanolamine lauryl ether sulfate and the like.

The benzotriazole, the copolymer of methyl vinyl ether and Maleic anhydride and the compounds that contain a glutamate residue, such as glutamic acid, sodium glutamate, potassium glutamate and the like suitable as component (B) for the present gowns are known substances. The copolymer of methyl vinyl ether and maleic anhydride is generally a reaction product of equimolar Amounts of methyl vinyl ether and maleic anhydride and is represented by the following formula:

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OCH,

OH,

CH

CH

In the m is a positive number _t is so large that a Agent with a specific viscosity of about 0.1

"5entsteht to about 5", based on a solution of 1 in methyl ethyl ketone at 25 ⁰ C ( "Gantrer AN"). When the copolymer is dissolved in water to form an acid derivative having the following

Formula unit: ',,

CH.

OCH,

CH

CH I c

CH

~ O

OH ..

An aqueous solution of the agents according to the invention in which. component (B) contains the copolymer of methyl vinyl ether and maleic anhydride, accordingly contains the acid derivative of this copolymer «■"". - " ^£ - ^{} r} - ^; - ■■■■ - ■■■ - ■

The agents according to the invention for preventing tarnishing are normally in the form of an aqueous solution with an initial pH in the range from -4.0 to -8, O _1, preferably in the range from 4.0 to 5> 5 » used. If necessary,." - "- ■ appropriate amounts of acidic or alkaline substances can be added

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sets cookers to keep the pH within the range given above To keep boundaries.

The invention is further illustrated by the following examples.

Example 1

A mixture of 0.5 parts by weight of a copolymer of methyl vinyl ether and sharkic anhydride ("Gantrez AN 1195 und 0.04 parts by weight of a non-ionic surfactant of the formula:

(C ₉ H ₁₉ ) ^ (C ₆ H ₄ ) "0- / ~ CH ₂ CH ₂ O_7x CH ₂ CH ₂ OH

in which χ equals 9 to 10, was mixed with a sufficient amount of water / water to make an aqueous solution, the 0.04 wt% of the nonionic surfactant Substance and 0.5 wt .- / »of the acid derivative of the copolymer contained. This solution had a pH in the range from 4.0 to 5.5-

An object made of tarnished copper was treated with a mixture of citric acid, sodium chloride, and ferric sulfate and a non-ionic surfactant cleaned, until it had a shiny surface. This clean, shiny object is then kept for 1 1/2 minutes at 85 to 95 ° C submerged the solution given above to prevent tarnishing. The item was removed from the solution, Drained for 1 1/2 min and allowed to air dry. The article was satisfactorily stable after the treatment against tarnishing due to atmospheric moisture, Carbon dioxide, air, incidental atmospheric contaminants and other handling.

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At game 2

A mixture of 1 part by weight of sodium glutamate and 0.04 part by weight a non-ionic surfactant der Formula:

(C ₉ H ₁₉ ) - (C ₆ H ^) - O- / ~ CH ₂ CH ₂ O_7 _x --CH ₂ CH ₂ OH,. .,

χ is equal to 30 to 40, was much nit V / ε as it is mixed in that an aqueous solution was formed containing 1 wt .- ^ o sodium glutamate and 0.04 wt -. containing ^C, O of the non-ionic surfactant . This solution had a pH of 4 to 5.5

Originally a tarnished copper article which had been purified as described in Example 1, was immersed in the above mentioned Lösuug against the attempts, and treated accordingly as the first The article thus treated had a satisfactory stability against normal tarnishing.

Example 3

A mixture of _r 0 2 parts by weight of the copolymer of Example 1, 0.1 parts by weight of benzotriazole and 0.04 wt .-- share of the nonionic surfactant of Example 1 was mixed with sufficient water to form a solution wäürige was that 0.3 wt -.% of the mixture of the acid derivative of the copolymer and benzotriazole and 0.04 wt .-% contained non-ionic surfactant. This solution had a pH of 4.0 to 5.5.

An originally tarnished copper object, which accordingly Example 1 was cleaned, was immersed in the so prepared anti-tarnishing solution and accordingly the example 1 treated further. So treated

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The article had satisfactory stability against normal tarnishing.

Example 4

A mixture of 0.2 part by weight of sodium glutamate and 0.04 part by weight the non-ionic surfactant des Example 1 was mixed with enough water to produce an aqueous solution containing 0.2% by weight of sodium glutamate contained. This solution was then acidified to pH 4 with acetic acid to remove the sodium glutamate contained therein convert to glutamic acid.

An originally started, cleaned according to Example 1 Copper object was immersed in the tarnishing prevention solution thus prepared and accordingly the example 1 treated further. The article so treated was stable to normal tarnishing.

Although in the present description mainly a prevention of tarnishing of copper and copper-containing Alloys, such as brass and bronze, are spoken of, it goes without saying that this means of prevention tarnishing is suitable for protecting all metal surfaces that tend to tarnish.

PATENT CLAIMS:

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Claims (1)

Claims .1)) Means to prevent tarnishing of metal surfaces, - characterized by a mixture of (A) a non-ionic or anionic surface-active Substance and (B) a substance such as a compound containing a glutamate residue, a copolymer of methyl vinyl ether and maleic anhydride and / or a mixture of such a copolymer with benzotriazole. 2) Means according to claim!, Characterized g e k e η η ζe i c hn et that the ingredients in amounts of 0.04 to 0.4 ". Parts by weight (A) and 0.1 to 2 parts by weight (B) are included. 3) Means according to claim 1 or 2, characterized in that g e k en η draw t that the surfactant is a non-ionic NOnylphenylpOlyäthylenglykoläther. · A) Means according to claim 1 to 3> characterized in that the surface-active substance / the formula: - - CH ₉ CH ₉ OH U. cL where χ is an integer between 5 and 70. 5) Means according to claim "1 to 4-, thereby g e k e η η ζ. e i c h η e t that component (A) 0.04 to 0.4 Parts by weight of a non-ionic surfactant and component (B) 0.1 to 2 parts by weight of a copolymer from methyl vinyl ether. and maleic anhydride. . -10- 00 98 407 2 123 1A-37 - 10 - 6) Application of the middle oil according to claim 1 to 5 in aqueous solution, the solution being 0.04 to 0.4% by weight (A) and contains 0.1 to 2% by weight of (B). 62XXIV 0-0 9840/2123