RU2601849C2 - Agent for cleaning surface of articles made from nonferrous metals - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to cleaning surface of articles made from non-ferrous metals, particularly ancient and modern coins, articles cultural and general purposes, jewellery, as well as for removal of corrosion products and man-made contaminations from surfaces of articles made from non-ferrous metals. Agent for cleaning surface of articles made from nonferrous metals comprises, %: disodium salt of ethylenediaminetetraacetic acid (Trilon B) - 1.0-1.5; organic acids - 1.5-25.0; Synthanol DS-10 - 0.12-0.20; tris(hydroxymethyl)aminomethane (Tris) - 0.2-5.0; alkali - 5.0-10.0; sulphonol - 0.05-0.1; distilled water - up to 100. As organic acids agent contains tartaric, sulphanilic and aminoacetic acid, and as alkali it contains KOH or NaOH.

EFFECT: agent is a colourless, non-foaming odourless liquid, and is stable during prolonged storage at room temperature; invention provides effective cleaning of surface of articles made from nonferrous metals and is safe for consumer health.

1 cl, 3 ex

Description

The invention relates to household chemicals and is intended for cleaning surfaces of objects made of silver, gold and other noble metals: coins (old and modern), cultural and historical items, jewelry, etc., as well as for cleaning corrosion products and contaminants of anthropogenic origin of surfaces of objects made of non-ferrous metals. The invention can be used in everyday life, in the jewelry industry, in museum storages, in antique shops, numismatics, in the automotive industry and electrical engineering for cleaning wires, terminals, for cleaning the outer surface of pipelines made of non-ferrous metals, in the armed forces for cleaning guns weapons for the purpose of removing from the surface of the channels of the barrels of soot, residues of copper and its alloys (bronze), lead and their oxides remaining from bullets after firing.

As a result of the storage or use of products made of precious metals, especially silver, the surface of these products is usually coated with corrosion products. This leads to the fact that the products lose their appearance and attractiveness. There is a need to clean (restore) the surface of the product, which is especially true when applied to old coins and jewelry.

As a result of storage or operation of products made from non-ferrous metals, the surface of these products is usually covered with corrosion products of different colors: black, green, blue, whitish, etc., depending on what metal the item is made of. This leads to the fact that the products lose their appearance and attractiveness. There is a need to clean (restore) the surface of the product, which is especially true when applied to old coins.

Currently, the most widely used methods of liquid (chemical) cleaning of metal surfaces. They have obvious advantages over methods such as mechanical exposure, ultrasonic treatment, electrolytic or plasma chemical etching, etc., due to their efficiency, versatility, low metal loss and, in some cases, due to improved surface properties of the processed products.

There are many ways of chemical cleaning of surfaces of objects made of non-ferrous metals. These methods can be used if the necessary composition is at hand or components for its preparation are commercially available. In practice, users typically use the following cleaning products:

1. Aqueous solutions of acids: acetic, citric, oxalic.

2. Aqueous or aqueous-alcoholic solutions of ammonia.

3. Digestion in vegetable or liquid paraffin.

4. The use of household chemicals: "Fairy", "AOS", "Mr. Muscle" and others.

5. Use a warm soapy solution or jelly made from laundry soap.

All of these methods have, apparently, only one advantage, which is the availability of ingredients. The disadvantages of these methods are most often associated with their excessive aggressiveness. With careless handling of these agents, not only the layer of corrosion products, but also the metal itself can dissolve.

Known paste for cleaning metal surfaces from corrosion products [USSR patent No. 985149 (1982)] containing phosphoric acid, ethyl alcohol, water glass, butyl cellosolve, methylene chloride, kaolin, water. However, this paste, firstly, is ineffective for cleaning surfaces of non-ferrous metals, secondly, it contains toxic components: butyl cellosolve, methylene chloride, and thirdly, it contains kaolin - an abrasive. The use of any abrasive, no matter how fine grinding it is, can spoil the surface of the product, especially if there is a fine pattern on it. The inconvenience also causes the complexity of the method of preparation of the paste.

Abrasive components are also included in a number of other means for cleaning metal surfaces from corrosion products and residues of varnishes and adhesives [USSR patent No. 1636434 (1991), RF patent No. 2199581 (2003), RF patent No. 2410416 (2009)]. In addition, these products contain toxic and unsafe organic solvents and acids. These products are ineffective for cleaning surfaces of non-ferrous and noble metals, after their use a thorough washing of the product with water is required.

There is a method of cleaning the surface of silver products, which consists in the use of a porridge paste consisting of 20 g of Trilon B, 20 g of sodium bicarbonate and 100 g of water [RF patent No. 2453635 (2012)]. The disadvantage of this method is associated with the difficulty of removing residual paste from the surface of the object after cleaning, due to the limited solubility of the solid components of the paste in water. This is especially true if the surface of the subject has a complex relief, deep pattern.

A known solution for removing a sulfide film from a silver surface containing thiourea, sulfuric, isonicotinic acid and metol [US patent No. 1033573, C23P 1 \ 056 (1983)]. The use of this solution has a significant drawback associated with the fact that the removal of the sulfide film is often accompanied by the dissolution of the silver base. This is especially true for cleaning silver-plated surfaces.

Known tool for cleaning the surfaces of copper, silver and gold coins "Industrial Strength Coin Brightner MS 70", manufacturer "Betterbilt Chemical", USA) from corrosion products - adopted by us as a prototype.

The composition of this agent includes butyl cellosolve, potassium hydroxide, sodium gluconate, a mixture of disodium salts of hexyl diphenyl ether disulfonate and dihexyl diphenyl ether disulfonate, water. This tool is quite effective. It is often used by numismatists to restore the surface of old coins made of non-ferrous metals. However, along with efficiency, users also note some aggressiveness of this tool: along with dissolving corrosion products, it can also dissolve the metal itself when not handled properly. In addition, the presence of butyl cellosolve and disodium salts of hexyl diphenyl ether disulfonate and dihexyl diphenyl ether disulfonate in the composition makes one doubt the safety of the agent. Butyl cellosolve is an organic, high boiling but flammable solvent. In light of contact with air, explosive peroxide compounds can form. When ingested through the skin or mouth, it can cause headache, dizziness, nausea, and vomiting [http://www.chemicalbook.com/]. The above derivatives of diphenyl ether, which play the role of surfactants in the composition of the agent, when ingested through the skin, mouth or by inhalation, can cause irreversible negative changes in the body [http://www.chemicalbook.com/RiskAndSafety.htm#hazards ].

The present invention is directed to the creation of a new effective and safe for consumer health means for cleaning the surface of products made of non-ferrous metals, which are solutions of low toxic, cheap components. The specified technical result is achieved by the fact that for surface cleaning using a tool that includes,%:

disodium salt of ethylenediaminetetraacetic acid (Trilon B) 1.0-1.5

organic acids 1.5-25.0

Sintanol DS-10 0.12-0.20

Tris (hydroxymethyl) aminomethane (Tris) 0.2-5.0

alkali 5.0-10.0

sulfonol 0.05-0.1

distilled water - up to 100%

Disodium salt of ethylenediaminetetraacetic acid (Trilon B) - complexon, a white crystalline powder, sparingly soluble in water, widely used in industry for washing heat power equipment, water treatment in boiler houses and heating systems, in the pulp and paper industry, in analytical chemistry and many other fields . LD ₅₀ = 2 g / kg [http://esis.jrc.ec.europa.eu].

Tartaric acid is a complexon, the acidity regulator is a white crystalline powder, sparingly soluble in water, a common natural compound found in the juices of many fruits and berries. Tartaric acid is used in the food industry as an antioxidant (E-334), in medicine and pharmacology, analytical chemistry, and the chemical industry. Low toxicity (4th hazard class) [http: benefit-him.ru/catalog/produces-and-chemicals-for-construction/tartaric-acid/].

Sulfanilic acid is a complexon, the acidity regulator is a white crystalline powder, highly soluble in water, and is widely used in industry for the production of dyes, pesticides, medicines, and analytical chemistry. LD ₅₀ = 6 g / kg [http://esis.jrc.ec.europa.eu].

The sodium salt of 5-sulfosalicylic acid is a complexon, the acidity regulator is a white crystalline powder, highly soluble in water.

Aminoacetic acid (glycine) is a complexon, the acidity regulator is a white crystalline powder, highly soluble in water. Non-toxic, used as a drug to improve cerebral circulation, an essential amino acid.

Tris (hydroxymethyl) aminomethane ("Tris") - complexon, medium acidity regulator - white crystalline powder, highly soluble in water. "Tris" is widely used in biochemistry and molecular biology as a buffer to reduce the acidity of the medium [G, Gomori, Methods Enzymology., 1, 138-146 (1955)]. According to its chemical structure, Tris is a primary amine and has properties characteristic of amines. Tris is practically non-toxic. It is used in medicine as an alternative to sodium bicarbonate in the treatment of metabolic acidosis [R.N. Kallet, R.M. Jasmer, J.M. Luce et al., Am. J. Resp. and Critical Care Medicine, V. 161, N 4, 1149-1153 (2000)], is part of the non-steroidal anti-inflammatory drug with analgesic and antipyretic effect "Dexalgin 25" [Instructions for medical use of the drug "Dexalgin 25"].

Syntanol DS-10 - a surfactant - a colorless paste, readily soluble in water, is a mixture of hydroxyethylated higher alcohols. It serves for degreasing a metal surface. Synthols are part of detergents, they are used as suspension stabilizers, emulsifiers, antistatic agents in the processing of synthetic fibers, degreasers of wool and metal surfaces, leveling agents for dyeing with vat dyes, wetting agents, additives in detergent compositions, dispersants. Low toxicity (4th hazard class).

Alkali - a regulator of the acidity of the medium, helps exfoliate and dissolve corrosion products - white granules, well soluble in water. KOH or NaOH were used as alkali.

Sulfonol - is a mixture of isomers of sodium salts of alkylbenzenesulfonic acids, readily soluble in water and possessing emulsifying properties. It is used as a surfactant to remove contaminants from various surfaces.

All ingredients of the composition are quite cheap.

The resulting composition will effectively clean the surface of non-ferrous metal products. When cleaning, for example, the surfaces of old coins, the resulting composition removes only corrosion products without affecting the patina, unlike Industrial Strength Coin Brightner MS 70.

The preparation of this composition is illustrated by the following example.

Example 1. In a glass, flat-bottomed, single-necked flask with a capacity of 150 ml, 50 ml of distilled water was poured, 5.0 g of potassium hydroxide was dissolved in it with shaking. 1.5 g of ethylenediaminetetraacetic acid disodium salt, 1.0 g of tartaric acid, 1.5 g of sulfanilic acid, 1.5 g of aminoacetic acid, 1.5 g of tris (hydroxymethyl) aminomethane, 0.20 g of Syntanol DS-10, 0.06 g of Sulfonol were successively added to the warm solution. Each ingredient was added after dissolving the previous one. After the formation of the solution, it was filtered through a folded paper filter. Distilled water was added to the filtrate to 100 g. The resulting solution was used for purification.

Obtained in example 1, the tool is a colorless, non-foaming liquid, odorless. It is stable during prolonged storage at room temperature.

All ingredients of the composition effectively complement each other, enhancing the cleaning properties. They are practically non-toxic compounds (hazard class 4). Unlike many products used to clean metal surfaces, the claimed product does not contain any organic solvents.

Cleaning agent examples

All work with a cleaning agent must be carried out in rubber gloves, glasses. Avoid contact with clothing, skin, mouth, eyes.

Example 2 (low degree of surface contamination by corrosion products). Dampen a cotton swab in a cleaner. Use a swab to wipe the surface of the item until you reach the desired result. Rinse the subject's surface with running water and dry it by wetting with filter paper. You can use a dry and soft cloth. If the final result does not satisfy you, repeat the indicated operations.

Example 3 (severe surface contamination by corrosion products). Use a cotton swab to clean the item. Wait 2-3 minutes, lightly wiping especially contaminated areas. Gather the remnants of the product with a cotton swab and rinse the surface of the item well with running water, then dry it by wetting with filter paper. You can use a dry and soft cloth. If the final result does not satisfy you, repeat the indicated operations.

Claims (2)

1. Means for cleaning the surface of non-ferrous metal products, characterized in that it contains disodium salt of ethylenediaminetetraacetic acid, organic acids, Syntanol DS-10, Tris (hydroxymethyl) aminomethane, alkali, sulfonol and distilled water in the following ratio,%:
disodium salt of ethylenediaminetetraacetic acid ("Trilon B") 1.0-1.5 organic acids 1,5-25,0 Sintanol DS-10 0.12-0.20 tris (hydroxymethyl) aminomethane ("Tris") 0.2-5.0 alkali 5.0-10.0 sulfonol 0.05-0.1 distilled water up to 100
while as organic acids it contains tartaric, sulfanilic and aminoacetic acids. 2. The tool according to claim 1, characterized in that it contains KOH or NaOH as alkali.