CN102212830A - Chemical de-rusting liquid and preparation method thereof - Google Patents

Abstract

The invention discloses chemical de-rusting liquid, which is prepared from the following raw materials in percentage by weight: 10%-20% of gallotannic acid, 10%-15% of phosphoric acid, and 20-30% of alcohol, 40-60% of water. The sum of the raw materials in percentage by weight is 100%. The preparation method comprises the following steps of: weighing the raw materials in formula amounts; adding the gallotannic acid, the phosphoric acid, the alcohol and the water into a stainless steel reaction kettle in sequence at normal temperature and normal pressure; then, heating; controlling the temperature in the reaction kettle at 15-35 degrees centigrade; and stirring at low speed for 10-30 min to obtain the de-rusting agent. The chemical de-rusting liquid disclosed by the invention has the advantages of good de-rusting performance, low cost, environmental friendliness, simple construction process and multiple functions of phosphorization, passivation and the like. The quality of a de-rusted and cleaned surface can reach grade Sa 2.5, phosphorization and passivation are carried out on a metal surface simultaneously, and the chemical de-rusting liquid dose not generate acid mist and does not need heating in a use process and is convenient to use.

Description

A kind of chemical derusting liquid and preparation method thereof

technical field

The invention belongs to the technical field of metal surface cleaning, and in particular relates to a rust removing liquid, in particular to a chemical rust removing liquid and a preparation method thereof.

Background technique

Rust removal or antirust treatment on metal surfaces is the basic process for metal products to prevent corrosion. Commonly used rust removal methods include manual rust removal, mechanical rust removal and chemical rust removal. Chemical rust removal mainly uses rust remover or rust remover liquid, and uses acid to react with metal oxides to dissolve the rust layer and remove the rust products on the metal surface, which is commonly referred to as pickling. rust removal. Compared with manual derusting and mechanical derusting, chemical derusting has the advantages of good effect, high efficiency, simple process operation, low cost, and is not limited by the shape and site of the workpiece. It is a widely used derusting method at present. .

At present, the most used chemical rust remover is pickling rust remover. The commonly used acid is hydrochloric acid or sulfuric acid. The acid concentration is between 7% and 15%. To prevent acid from corroding steel, a small amount of corrosion inhibitor can be added. Ordinary pickling and derusting agents are labor-intensive, costly, and produce a large amount of acid mist during use. The construction conditions are harsh and the functions are single, which makes it difficult to meet the needs of production and construction. For example, the patent publication number CN881064262 discloses a rust remover that uses hydrochloric acid as the main agent for pickling and adds various auxiliary agents. A kind of rust remover with hydrochloric acid as main agent, hexamethyltetramethylene amine and surfactant as auxiliary agent also has problems such as higher product cost and single function. The Chinese patent with the publication number 93111873.5 discloses a solid rust remover composed of solid acid, wetting and penetrating agent, corrosion inhibitor and rust removal accelerator, which has the problems of inconspicuous rust removal effect, high use cost and single function .

Contents of the invention

The object of the present invention is to provide a chemical descaling solution and its preparation method. The chemical descaling liquid is prepared from various functional materials, which overcomes the traditional pickling descaling agent with high labor intensity, high cost, and A large amount of acid mist, poor construction conditions and single function, etc., the derusting solution of the present invention has good derusting performance, low cost, environmental friendliness, simple construction process, and has certain degreasing, phosphating and passivating effects.

To achieve the above object, the present invention adopts the following technical solutions:

A chemical derusting solution, characterized in that it is prepared from the following raw materials in weight percentage: tannic acid: 10%-20%; phosphoric acid: 10%-15%; alcohols: 20%-30%; water: 40% %~60%, the sum of the weight percentages of the above raw materials is 100%.

The alcohols are monohydric or polyhydric alcohols with C _1-6 alkyl carbon skeletons.

The preparation method of the above-mentioned chemical descaling solution is characterized in that it comprises the following steps: weighing the raw materials of the formula amount, adding tannic acid, phosphoric acid, alcohols and water to the stainless steel reaction kettle successively under normal temperature and pressure, and then heating , control the temperature in the reactor at 15~35℃, stir for 10~30min to get the chemical derusting solution.

The chemical derusting solution of the present invention contains solid weak acid, phosphating agent and alcohol additives, has good derusting performance, low cost, environment-friendly, simple construction technology, and has multifunctional advantages such as phosphating and passivation. It has a good derusting effect when used under certain conditions. The surface quality of derusting cleaning can reach Sa2.5 level and the metal surface phosphating and passivation treatment can be completed at the same time. No acid mist is generated during use, no heating is required, and it is easy to use. At the same time, because the raw materials of the present invention do not use heavy metal components commonly used in the phosphating and passivation of metal surfaces, the pollution to the environment can be reduced.

Detailed ways

The chemical derusting solution of the present invention is composed of the following raw materials in weight percentage: tannic acid: 10%~20%; phosphoric acid: 10%~15%; alcohols: 20%~30%; water: 40%~60% , The sum of the percentages by weight of the above raw materials is 100%. Alcohols are monohydric or polyhydric alcohols with carbon skeleton C _1-6 alkyl.

The preparation method of the above-mentioned chemical descaling liquid: take the raw materials of the formula amount, add tannic acid, phosphoric acid, alcohols and water to the stainless steel reaction kettle in turn under normal temperature and pressure, and then heat to control the temperature in the reaction kettle at 15~ Stir at 35°C for 10-30 minutes to obtain the chemical descaling solution.

The present invention will be further explained by the following examples.

Example 1:

Get tannic acid, phosphoric acid and n-butanol according to the required raw material weight of table 1, under normal temperature and pressure, add tannic acid, phosphoric acid and n-butanol successively in reactor, add water to solution gross weight and be 100Kg, then Heat at 20°C for 30 minutes, and stir during the heating process to obtain a chemical descaling solution.

The raw material of table 1 embodiment 1

Example 2:

Get tannic acid, phosphoric acid and ethanol according to the required raw material weight of table 2, under normal temperature and pressure, add tannic acid, phosphoric acid and ethanol successively in the stainless steel reactor, add water to solution gross weight and be 100Kg, then in 15 Heating at ℃ for 30 minutes, stirring during the heating process, to obtain a chemical descaling solution.

The raw material of table 2 embodiment 2

Example 3:

Get tannic acid, phosphoric acid and isoamyl alcohol according to the required raw material weight in Table 3, under normal temperature and pressure, add tannic acid, phosphoric acid and isoamyl alcohol in the stainless steel reaction kettle successively, add water again until the total weight of the solution is 100Kg , and then heated at 35°C for 10 minutes, stirring during the heating process, to obtain a chemical rust removal solution.

The raw material of table 3 embodiment 3

Example 4:

Get tannic acid, phosphoric acid and propylene glycol according to the required raw material weight of table 4, under normal temperature and pressure, add tannic acid, phosphoric acid and propylene glycol successively in stainless steel reactor, add water to solution gross weight and be 100Kg, then in 30 Heating at ℃ for 20 minutes, stirring during the heating process, to obtain a chemical descaling solution.

The raw material of table 4 embodiment 4

Example 5:

Take tannic acid, phosphoric acid and ethylene glycol according to the required raw material weight in Table 5, and under normal temperature and pressure, add tannic acid, phosphoric acid and ethylene glycol to the stainless steel reactor successively, and then add water until the total weight of the solution is 100Kg , and then heated at 25°C for 25 minutes, stirring during the heating process, to obtain a chemical rust removal solution.

The raw material of table 5 embodiment 5

Chemical derusting liquid effect test of the present invention:

Use a steel wire brush to remove floating rust on the surface of the rusted workpiece, and clean it with a high-pressure air gun. Brush the chemical derusting solution of the present invention to form a passivation film on the surface of the workpiece. After two hours, carry out the following tests respectively:

(1) Hardness test of passivation film: Pencil hardness test was carried out on the passivation film of the test piece treated with the derusting solution prepared in Example 1, Example 2, Example 3, Example 4 and Example 5.

(2) Passivation film adhesion test: GB/T9286- 1998 Cross-cut test method to test adhesion.

The test results are shown in Table 6:

Table 6 Performance evaluation of multifunctional chemical rust remover

As can be seen from Table 6, the hardness of the metal surface treated with the derusting solution of the present invention all reaches the H grade, and the adhesion reaches the first grade. The test results show that the protective film formed by the product of the present invention has good protective performance on the metal surface .

After the metal surface is derusted, in order to prevent re-rusting and improve the adhesion of the coating film, a series of chemical treatments are often used to form a protective film on the surface. Commonly used treatment methods include oxidation, phosphating and passivation. The chemical descaling liquid of the present invention comprehensively considers degreasing, descaling, phosphating and passivation, can reduce working procedures and labor intensity. The solid weak acid contained in it can effectively remove the rust products such as metal oxides, metal sulfides and metal weak acid salts formed on the metal surface under the synergistic effect of alcohol additives, and the solid weak acid used can effectively remove the corrosion products on the metal surface. Less corrosive. While removing rust on the metal surface, the phosphating agent in the raw material can react with the metal to form a dense phosphating film on the metal surface quickly to effectively prevent rust protection on the surface. The surface quality of derusting and cleaning can reach Sa2.5 level.

In order to verify the application effect of the chemical derusting liquid of the present invention in engineering, the raw material formula of Example 1 is specially selected as an experimental reagent to prepare the chemical derusting liquid, and the metal structure of the bridge in the Zhashui section of the Xikang Expressway is used for derusting and painting construction , after construction, no paint film cracking or peeling phenomenon occurred within two years, the results show that the present invention has good application performance and meets the engineering construction requirements.

Claims (3)

1. A chemical derusting liquid, characterized in that, is made from the following raw materials in weight percentage: tannic acid: 10%~20%; phosphoric acid: 10%~15%; alcohols: 20%~30%; water : 40%~60%, the sum of the weight percentages of the above raw materials is 100%. 2. chemical derusting liquid as claimed in claim 1, is characterized in that, described alcohols is the monohydric alcohol or polyhydric alcohol of carbon skeleton C _1-6 alkyl. 3. the preparation method of chemical derusting liquid as claimed in claim 1, is characterized in that, comprises the steps: take the raw material of formula quantity, under normal temperature and pressure, add tannic acid, phosphoric acid successively in stainless steel reactor Mix with alcohol and water, then heat, control the temperature in the reactor at 15-35°C, and stir for 10-30 minutes to obtain the chemical rust removal solution.