CN111172523A - Water-based rust converting agent and preparation method and technology thereof - Google Patents

Abstract

The invention relates to the technical field of rust treatment, in particular to a water-based rust converting agent and a preparation method technology thereof, which comprises the following raw materials: the corrosion inhibitor comprises inorganic acid, phosphate, organic phosphonic acid, silane, organic acid, a corrosion inhibitor, an active agent, a defoaming agent and water, wherein the inorganic acid is phosphoric acid, the phosphate is zinc dihydrogen phosphate, the organic phosphoric acid is HEDP, the organic acid is citric acid, the silane is selected from silane coupling agents, the corrosion inhibitor is thiourea, the active agent is fatty alcohol polyoxyethylene ether AEO-3, and the defoaming agent is DF7010 defoaming agent. According to the invention, phosphoric acid, HEDP and rust react to generate a black and gray phosphate and organic phosphonate hybrid film, zinc dihydrogen phosphate is combined with a phosphating film formed by a metal iron substrate, and a three-dimensional net-shaped structure film of silane is used as an outer layer wrapping effect, so that the formed anti-rust film has better corrosion resistance and scratch resistance, has stronger binding force with an iron and steel substrate and paint, is fine, and has excellent performance in appearance or performance.

Description

Water-based rust converting agent and preparation method and technology thereof

Technical Field

The invention relates to the technical field of rust treatment, in particular to a water-based rust converting agent and a preparation method technology thereof.

Background

When steel is exposed in air with moisture, iron oxide, namely rust, is formed on the surface of the steel, and the existence of the rust prevents anticorrosive paint on the surface of the steel from being adhered, so that rust removal treatment is required before paint spraying.

At present, the rust removal of steel mainly comprises mechanical rust removal (shot blasting, sand blasting and manual polishing) and chemical rust removal, and the rust removal of an outdoor steel structure mostly adopts shot blasting and manual polishing. And the shot blasting cost is high, the dust pollution is large, the construction is inconvenient, the manual polishing efficiency is low, the labor cost is high, and the traditional pickling cannot meet the outdoor operation. The existing rust conversion coating is suitable for light-rust steel construction and is not suitable for moderate to severe rust; the existing rust converting agent has extremely poor conversion effect or even can not convert oxide scale, particularly red oxide scale

Therefore, we propose an aqueous rust converting agent and a preparation method thereof for solving the above problems.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a water-based rust converting agent and a preparation method and technology thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a water-based rust converting agent which comprises the following raw materials in parts by weight: 20-25 parts of inorganic acid, 10-15 parts of phosphate, 12-18 parts of organic phosphonic acid, 1-5 parts of silane, 2-6 parts of organic acid, 0.2-0.6 part of corrosion inhibitor, 0.1-0.3 part of activator, 0.05-0.1 part of defoaming agent and 45-55 parts of water.

Preferably, the inorganic acid is phosphoric acid, the phosphate is zinc dihydrogen phosphate, the organic phosphoric acid is HEDP, and the organic acid is citric acid.

Preferably, the silane is selected from silane coupling agents, and the silane coupling agent is one or two of KH-550 and KH-560.

Preferably, the corrosion inhibitor is thiourea, the active agent is fatty alcohol polyoxyethylene ether AEO-3, and the defoaming agent is DF7010 defoaming agent.

Preferably, the preparation method of the aqueous rust converting agent comprises the following steps:

s1: adding sufficient tap water, sequentially adding citric acid and thiourea, and stirring until the citric acid and the thiourea are completely dissolved;

s2: adding zinc dihydrogen phosphate, and stirring to dissolve completely;

s3: sequentially adding phosphoric acid and HEDP, and uniformly stirring;

s4: slowly adding silane while stirring, and continuously stirring for 3-5 minutes;

s5: and sequentially adding AEO-3 and the defoaming agent while stirring, and stirring until the solution is uniform, milky and semitransparent to obtain the transforming agent.

Preferably, in the S3, the stirring time is 5-10 minutes, and the stirring time in the S5 is 15-20 minutes

Compared with the prior art, the invention utilizes the reaction of phosphoric acid, HEDP and rust to generate a black gray phosphate and organic phosphonate hybrid film, and the combination of zinc dihydrogen phosphate and a phosphating film formed by a metal iron substrate, and the three-dimensional net-shaped structural film of silane is used as an outer layer wrapping effect, so that the formed anti-rust film has better corrosion resistance and scratch resistance, has stronger binding force with an iron and steel substrate and paint, is delicate, and has excellent performance in appearance or performance.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. When "mass, concentration, temperature, time, or other value or parameter is expressed as a range, preferred range, or as a range defined by a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, a range of 1 to 50 should be understood to include any number, combination of numbers, or subrange selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50, and all fractional values between the above integers, e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. With respect to sub-ranges, specifically consider "nested sub-ranges" that extend from any endpoint within the range. For example, nested sub-ranges of exemplary ranges 1-50 may include 1-10, 1-20, 1-30, and 1-40 in one direction, or 50-40, 50-30, 50-20, and 50-10 in another direction. "

The present invention will be further illustrated with reference to the following specific examples.

The invention provides a water-based rust converting agent which comprises the following raw materials in parts by weight: 20-25 parts of inorganic acid, 10-15 parts of phosphate, 12-18 parts of organic phosphonic acid, 1-5 parts of silane, 2-6 parts of organic acid, 0.2-0.6 part of corrosion inhibitor, 0.1-0.3 part of activator, 0.05-0.1 part of defoaming agent and 45-55 parts of water.

Wherein, the inorganic acid is phosphoric acid, the phosphate is zinc dihydrogen phosphate, the organic phosphoric acid is HEDP, the organic acid is citric acid, the silane is selected from silane coupling agent, the silane coupling agent is one or two of KH-550 and KH-560, the corrosion inhibitor is thiourea, the activator is fatty alcohol polyoxyethylene ether AEO-3, and the defoaming agent is DF7010 defoaming agent.

Further, a preparation method of the water-based rust converting agent is also disclosed, and comprises the following steps:

s1: adding sufficient tap water, sequentially adding citric acid and thiourea, and stirring until the citric acid and the thiourea are completely dissolved;

s2: adding zinc dihydrogen phosphate, and stirring to dissolve completely;

s3: sequentially adding phosphoric acid and HEDP, and uniformly stirring;

s4: slowly adding silane while stirring, and continuously stirring for 3-5 minutes;

s5: and sequentially adding AEO-3 and the defoaming agent while stirring, and stirring until the solution is uniform, milky and semitransparent to obtain the transforming agent.

Examples

Test subjects: Q235B H-shaped steel with moderate rust on surface and black scale and red scale

The test was based on phosphoric acid, and the conversion effect was observed by using different phosphoric acid concentrations in combination with different zinc dihydrogen phosphate and HEDP concentrations:

and (3) conversion result: the experimental groups 1, 2 and 3 have incomplete conversion on rusted parts and have the phenomena of pulverization and whitening, and can convert black oxide skins and red oxide skins into films for drying the films for 10 min; the experiment group 4 has incomplete conversion to rusty parts and slight whitening, and black oxide skin and red oxide skin can be converted, and the dry film time is 20 min; the experiment group 5 has complete conversion on rust, black oxide skin can be converted, the dry film time is 20min, red oxide skin can be converted, and the dry film time is 2 h; the experiment group 6 has complete conversion on rust, the black oxide scale can be converted, and the red oxide scale can be converted but the dry film speed reaches 24 hours; the experimental groups 7, 8 and 9 completely convert rust, black oxide scale can be converted, but red oxide scale cannot be dried in 24 h.

According to the results of the above experiments, the conversion effect is best when the amount of the phosphoric acid is 20%, and the zinc dihydrogen phosphate is 10% and the HEDP is 15%.

KH-550 silane blocking:

the surface of the anti-rust film converted from the main active ingredients is still rough and dull, and experiments show that the formed conversion film is not waterproof, and once the dry film is contacted with water again, the conversion film is seriously pulverized and whitened.

Furthermore, citric acid is selected as a complexing agent, on one hand, the citric acid can complex Fe3+, on the other hand, the citric acid also participates in the reaction of the conversion film, the reaction product can form a hybrid film with a main component reactant, the corrosion resistance and the bonding force of the conversion film are improved, and the optimal use ratio is 5%.

Specifically, the corrosion inhibitor thiourea is applied to effectively prevent the corrosion of acid liquor to the steel substrate, and avoid the poor quality of a conversion coating and the influence on the performance of steel caused by excessive corrosion. The corrosion inhibitor used in excess will reduce the reaction rate of the conversion coating, so the optimum addition amount is 0.5%.

Specifically, the addition of the surfactant can enable the conversion agent to have better penetrating and wetting capacity on the rust, so that the conversion agent can penetrate into the rust inner layer, and the reaction is more sufficient. The optimum use ratio is 0.2.

In addition, the addition of the active agent can cause the transforming agent solution to generate bubbles, the bubbles are easily generated on a workpiece in the spraying process, a large number of vortex points are formed behind a dry film of a transforming film, and the spraying of paint is influenced, so that the problem can be avoided by adding a proper amount of the defoaming agent, and the using amount is preferably 0.1%.

In conclusion, the invention has simple preparation and low cost, can directly spray and brush the rusted and oxidized steel surface to convert the rust and the oxidized scale into a layer of rust-proof film, has high conversion speed, avoids the link of rust removal, can directly spray and spray anticorrosive paint on the rust-proof film, improves the construction efficiency and reduces the construction cost.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (6)

1. The water-based rust converting agent is characterized by comprising the following raw materials in parts by weight: 20-25 parts of inorganic acid, 10-15 parts of phosphate, 12-18 parts of organic phosphonic acid, 1-5 parts of silane, 2-6 parts of organic acid, 0.2-0.6 part of corrosion inhibitor, 0.1-0.3 part of activator, 0.05-0.1 part of defoaming agent and 45-55 parts of water.

2. The aqueous rust converting agent according to claim 1, wherein the inorganic acid is phosphoric acid, the phosphate is zinc dihydrogen phosphate, the organic phosphoric acid is HEDP, and the organic acid is citric acid.

3. The aqueous rust converting agent according to claim 2, wherein the silane is selected from silane coupling agents which are one or both of KH-550 and KH-560.

4. The aqueous rust converting agent according to claim 3, wherein the corrosion inhibitor is thiourea, the activator is fatty alcohol polyoxyethylene ether AEO-3, and the defoamer is DF7010 defoamer.

5. A method for preparing the aqueous rust converting agent according to claim 4, characterized by comprising the steps of:

s1: adding sufficient tap water, sequentially adding citric acid and thiourea, and stirring until the citric acid and the thiourea are completely dissolved;

s2: adding zinc dihydrogen phosphate, and stirring to dissolve completely;

s3: sequentially adding phosphoric acid and HEDP, and uniformly stirring;

s4: slowly adding silane while stirring, and continuously stirring for 3-5 minutes;

s5: and sequentially adding AEO-3 and the defoaming agent while stirring, and stirring until the solution is uniform, milky and semitransparent to obtain the transforming agent.

6. The method of claim 5, wherein the stirring time in S3 is 5-10 min, and the stirring time in S5 is 15-20 min.