CN111621209B

CN111621209B - Aqueous antirust liquid suitable for organic composite film forming on steel surface

Info

Publication number: CN111621209B
Application number: CN202010498656.6A
Authority: CN
Inventors: 刘宁华
Original assignee: Guangzhou Hoso Environmental Protection Technology Co ltd
Current assignee: Guangzhou Hoso Environmental Protection Technology Co ltd
Priority date: 2020-06-04
Filing date: 2020-06-04
Publication date: 2021-06-29
Anticipated expiration: 2040-06-04
Also published as: CN111621209A

Abstract

The invention discloses an aqueous antirust liquid suitable for organic composite film formation on a steel surface, which can form an organic composite protective film on the steel surface to prevent rusting again. The aqueous antirust liquid comprises the following components in concentration: 1000-5000 ppm of boron-containing copolymer, 600-3000 ppm of organic acid containing a ring structure, 500-1000 ppm of compound containing polycarboxyl, 50-300 ppm of film forming aid, 50-100 ppm of catalyst and the balance of pure water; the film-forming assistant is an oxyacid alkali metal salt compound; the pH value of the aqueous antirust liquid is 8.5-9.5. The antirust liquid does not contain strong base, phosphorus and any toxic heavy metal, can adapt to dipping or spraying, has the treatment temperature of normal temperature, the treatment time of soaking for 60-180 s and spraying for 10-30 s, and simultaneously has high bonding strength with a matrix and subsequent organic polymer coatings (such as paint, powder and the like) and obviously improved corrosion resistance.

Description

Aqueous antirust liquid suitable for organic composite film forming on steel surface

Technical Field

The invention relates to the technical field of rust prevention of steel surfaces by an environment-friendly metal surface treatment technology, in particular to aqueous rust prevention liquid suitable for organic composite film formation of the steel surfaces.

Background

Iron and steel, i.e. iron-carbon alloy, is a binary alloy with iron and carbon as components. The processing piece is widely applied to various aspects in industrial production and life, plays an important role in human life and work, and is the basis of technological development. However, in the processes of production, processing and transportation of steel, the steel inevitably contacts with environmental media (such as water, oxygen, acid and alkali media, organic media and the like in the air) to generate an electrochemical corrosion reaction to generate rust, the worldwide steel output is over billions of tons since 2008, the average annual increase is kept over 3%, the national steel output accounts for about 50% of the worldwide total output, and the loss of the steel due to rust is about 25%, so that the rust prevention of the surface of a steel workpiece is an essential important link. The temporary rust prevention method of metal comprises the steps of coating rust prevention oil, rust prevention water and wrapping a gas phase rust prevention packaging material, wherein the traditional rust prevention liquid contains a large amount of sodium nitrite, is easy to cause cancers, has high toxicity to human bodies and the environment, and has short rust prevention time. For workpieces needing long-term rust prevention, rust preventive oil is generally adopted, but the rust preventive oil can influence the next working procedure processing, brings flammable and explosive risks and is not beneficial to environmental protection and health.

With the implementation of national environmental protection policy and the increasing attention of human beings on environmental protection, the development of an environment-friendly aqueous antirust liquid has become a hot research problem. A great deal of research is carried out by many experts and scholars at home and abroad, for example, patent CN 108165966A discloses a metal spraying rust removing and preventing liquid which is formed by combining phosphoric acid, thiourea, sodium tripolyphosphate, sodium benzoate, ethylene diamine tetraacetic acid, triethanolamine, sodium chloride and sodium hypophosphite, and has the functions of removing rust and preventing rust, and protecting iron and nonferrous metal products and equipment. However, the formula of the antirust liquid contains a large amount of phosphorus-containing components, which easily causes the water body to be rich in oxidation, and the phosphate antirust liquid also has the defect of short antirust time. Patent CN 108165964 a discloses a polyaniline sol metal surface treatment agent, which is composed of the following raw materials by weight: 1-2 parts of sodium potassium tartrate, 110-120 parts of polyaniline sol, 1-2 parts of polydimethylsiloxane, 1-1 part of silane coupling agent kh 5500.7, 2-4 parts of sodium fluosilicate, 3-5 parts of triethyl phosphate, 0.1-0.2 part of 2-thiol benzimidazole and 0.5-1 part of nickel sulfamate, and the added sol can effectively improve the adhesive strength of a coating and metal, so that the metal protection is improved. However, the rust inhibitor is modified by a silane coupling agent, so that a large instability factor exists in the property of the rust inhibitor. The existing antirust agent generally has the problems of no environmental protection, short action time, unstable property and the like.

Therefore, it is necessary to develop a green, environment-friendly and high-performance aqueous rust preventive solution suitable for steel surfaces.

Disclosure of Invention

The invention aims to overcome the problems of high cost, low efficiency, environmental pollution, insecure and scratch-resistant formed antirust film and the like of the existing rust removing means, and provides the aqueous antirust liquid suitable for organic composite film forming on the surface of steel.

In order to solve the technical problems, the invention provides the following technical scheme:

the water-based antirust liquid suitable for the organic composite film forming on the surface of steel comprises the following components in concentration:

1000 to 5000ppm of a boron-containing copolymer,

600 to 3000ppm of an organic acid having a ring structure,

500 to 1000ppm of a compound containing a polycarboxyl group,

50 to 300ppm of a film-forming aid,

50 to 100ppm of a catalyst,

the balance of pure water;

the film-forming assistant is an oxyacid alkali metal salt compound; the pH value of the aqueous antirust liquid is 8.5-9.5.

The aqueous antirust liquid for the organic composite film formation on the steel surface forms a layer of compact multiple organic composite protective film on the steel surface by utilizing the reactivity and the synergistic effect of the boron-containing copolymer, so that the steel surface is prevented from rusting again. The antirust liquid does not contain strong base, phosphorus and any toxic heavy metal, can be suitable for dipping or spraying, is dipped at normal temperature for 60-180 s and sprayed for 10-30 s, is high in bonding strength with a matrix and subsequent organic polymer coatings (such as paint, powder and the like), is excellent in protective performance, is obviously improved in corrosion resistance, meets the current environment-friendly and use requirements, and has a good market prospect.

The aqueous antirust liquid is alkaline, and after the aqueous antirust liquid is sprayed on steel, the steel is slightly corroded by oxygen absorption under an alkaline condition to generate partial free ferrous ions and electrons, and the generated electrons are used as a film-forming initiator. Under the boosting of the catalyst, ferrous ions are firstly complexed with a compound containing polycarboxyl to start to form a bottom layer film, and free electrons activate the whole system to start to react. The boron-containing copolymer has a three-dimensional property, and attracts organic acid containing a ring structure, a compound containing polycarboxyl and an oxygen acid alkali metal salt compound to form a complex or a chelate in different directions by utilizing the electron deficiency characteristic of boron element and the help of the oxygen acid alkali metal salt compound, and the boron element is taken as the center to form perfect connection between the layer film and the layer film, so that the layer film does not exist independently, but is organically linked together, cannot be easily peeled off or penetrated, and the steel is compactly protected. The organic acid containing the ring structure can form plane extension, namely, all atoms of the ring compounds such as benzene rings and the like are in the same plane, so that the ring compounds are rapidly spread out among layers to form the antirust film.

Preferably, the boron-containing copolymer comprises one or more of ethyl borate, triphenyl borate, triisopropanolamine cyclic borate, but is not limited thereto.

Preferably, the organic acid containing a ring structure includes one or more of benzoic acid and a tricarboxylic acid, but is not limited thereto.

The rust prevention time of the steel workpiece is closely related to the compactness and the corrosion resistance of a rust prevention film of the steel workpiece, and what is important is how to help the metal resist the regeneration of rust on the premise of removing paint, oil stains and rust on the surface in order to effectively prolong the rust return time of the steel workpiece. The invention forms a layer of high-strength chemical reaction film on the surface of steel by utilizing the electron deficiency of boron in the boron-containing copolymer, the carrier effect of ester, the reaction activity of organic acid polyfunctional groups such as long carbon chain hydroxyl, double bonds on a carbon ring and the synergistic effect of the three groups, and has good antirust performance. Meanwhile, the boron atom has a bactericidal effect, so that the reproductive capacity of microorganisms in the antirust liquid can be effectively reduced, and the stability of the antirust performance can be better ensured.

Preferably, the compound containing a polycarboxyl group includes one or more of dibutyl sebacate, dioctyl sebacate and diisooctyl sebacate, but is not limited thereto.

As preferred carboxyl group-containing compounds dibutyl sebacate, dioctyl sebacate or diisooctyl sebacate, the multi-ortho carboxyl groups themselves can react with other functional groups, but the reactivity of each carboxyl group is different. Different chelates are formed by the chelate and the oxyalkali metal salt compound of the film forming assistant in the antirust liquid and are adsorbed on the surface of the steel layer by layer to form multiple antirust films, so that the compactness of the film layer is ensured, and the steel surface is effectively prevented from generating rust by oxidation reaction again. Because the reactivity of each carboxyl group is different, the surface of the formed antirust film is uneven, thereby ensuring that the substrate and the subsequent organic polymer coating (such as paint, powder and the like) have good bonding strength.

Preferably, the oxoacid alkali metal salt compound includes one or more of sodium citrate, sodium gluconate, and disodium edetate, but is not limited thereto.

Preferably, the catalyst is a rubidium salt.

Preferably, the catalyst comprises one or more of rubidium carbonate, rubidium sulfate and rubidium nitrate, but is not limited thereto.

Because rubidium salt has free electrons with strong activity, under the action of micro electrons generated by oxygen absorption corrosion of steel, extremely strong electron current can be generated instantly, so that ferrous ions are promoted to be complexed with a compound containing multiple carboxyl groups, the whole reaction process is started, and the film forming time is greatly shortened.

Preferably, the aqueous antirust liquid also comprises the following components in concentration: 1000 to 2000ppm of a pH stabilizer, but not limited thereto.

Because the organic acid containing a ring structure is used in the components to assist the rapid formation of the planar film, the pH value of the system is inevitably reduced, and the acidified antirust agent cannot achieve the ideal antirust effect, because the original oxygen absorption corrosion is converted into hydrogen evolution corrosion under the acidic condition of steel, countless bubbles are formed to continuously impact the antirust film, so that the antirust film cannot be formed, and the antirust effect cannot be achieved. Therefore, the pH value of the temperature system for adding the pH stabilizer is needed.

Preferably, the pH stabilizer includes triethanolamine, but is not limited thereto.

The pH stabilizer is preferably triethanolamine which has weak alkalinity and can react with acid to generate salt or ester, so that the pH value of the system can be lower and can be easily stabilized in a proper range. On the other hand, because of the lone pair electrons on the nitrogen atom, the triethanolamine can form a ligand to form a chelate with the boron-containing copolymer to assist in forming the anti-rust film.

Preferably, the aqueous antirust liquid suitable for organic composite film forming on the steel surface comprises the following components in concentration:

2500ppm of triisopropanolamine cyclic borate,

1700ppm of a tri-carboxylic acid,

1000ppm of dibutyl sebacate (DBP),

150ppm of sodium gluconate (sodium gluconate),

50ppm of a rubidium carbonate (Rb) in the form of a solid,

the balance of pure water;

the film-forming assistant is an oxyacid alkali metal salt compound; the pH value of the aqueous antirust liquid is 9.5.

In experiments, 2500ppm of triisopropanolamine cyclic borate, 1700ppm of tricarboxylic acid, 1000ppm of dibutyl sebacate, 150ppm of sodium gluconate film-forming aid and 50ppm of rubidium carbonate catalyst are found to be the most excellent and optimal choice for the aqueous antirust liquid formed by adjusting the pH value of the solution to 9.5.

The application of the aqueous antirust liquid suitable for the organic composite film formation on the steel surface is applied to the rust prevention of the steel surface to form an organic composite film.

The general method is as follows: and (3) treating the steel in aqueous antirust liquid to form a multiple organic composite protective film on the surface of the steel, and drying to obtain the multiple organic composite antirust film on the surface of the steel. The treatment method is dipping or spraying, the treatment temperature is normal temperature, the treatment time is 60-180 s of dipping and 10-30 s of spraying. Before the steel is treated by the aqueous antirust liquid, the surface of the steel is pretreated by paint removal, oil removal, rust removal and the like, a base material is exposed, and the surface of the steel is washed clean by water.

The implementation of the invention has the following beneficial effects:

(1) the multiple organic composite anti-rust film prepared on the surface of steel by using the film forming solution has excellent compactness, can effectively prevent the surface of steel from generating oxidation reaction again to generate rust, and can achieve the anti-rust time of 3-6 months in a closed environment; the binding force between multiple antirust film layers is strong, and the multiple antirust film layers cannot be easily damaged; meanwhile, the base material and the organic polymer coating (such as paint, powder and the like) are high in bonding strength and excellent in protective performance, the boiling water adhesion is 0 grade, and the single-side corrosion is less than 2mm after a 900-hour NASS test.

(2) The treatment process of the film forming solution is simple and easy to operate, and the treatment process is carried out at normal temperature without heating; the treatment time is short, and the film can be effectively formed by dipping for 90-120 s or spraying for 15-20 s.

(3) The formed anti-rust film layer takes boron, various carboxyl compounds and alkali metal chelate as main components, does not contain sodium nitrite, strong base, phosphorus and any toxic heavy metal, and contains boron atoms with a sterilization effect, so that the reproductive capacity of microorganisms in the anti-rust liquid can be effectively reduced, and the stability of the anti-rust performance can be better ensured.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to specific embodiments.

Example 1

2500ppm of triisopropanolamine cyclic borate, 1700ppm of tricarboxylic acid, 1000ppm of dibutyl sebacate, 150ppm of sodium gluconate film-forming aid and 50ppm of rubidium carbonate catalyst.

The components were dissolved in water under stirring, the pH of the solution was adjusted to 9.5, and pure water was added to a film-forming solution volume of 1000mL, to obtain a film-forming solution as described in this example.

The method for preparing the organic composite film with multiple steel surfaces by using the film forming solution comprises the following steps:

(1) pretreatment: firstly, cutting a steel sample of 50mm multiplied by 100mm, punching, and connecting an iron wire at the punched position; secondly, polishing the sample by using sand paper or treating the sample by using a chemical method until the sample is exposed out of the original color of the base material, and flattening and brightening the sample, completely removing paint, oil stain and rust, and wiping the sample clean for later use;

(2) and (2) placing the steel sample pretreated in the step (1) in the film forming solution prepared in the embodiment, immersing the steel sample in the film forming solution at normal temperature (17 ℃) for 60 seconds to finish film forming, taking out the sample, and drying or naturally airing to obtain multiple organic composite films on the surface of steel, thereby obtaining the steel workpiece coated with the multiple organic composite films.

Example 2

1500ppm of triisopropanolamine cyclic borate, 1000ppm of ethyl borate, 1000ppm of benzoic acid, 1000ppm of dioctyl sebacate, 100ppm of ethylene diamine tetraacetic acid as a film forming aid and 100ppm of rubidium sulfate as a catalyst.

The components were dissolved in water under stirring, the pH of the solution was adjusted to 9.0, and pure water was added to a film-forming solution volume of 1000mL, to obtain a film-forming solution as described in this example.

(2) and (2) placing the steel sample pretreated in the step (1) in the film forming solution prepared in the embodiment, immersing the steel sample in the film forming solution at normal temperature (10 ℃) for 120s to finish film forming, taking out the sample, and drying or naturally airing to obtain multiple organic composite films on the surface of steel, thereby obtaining the steel workpiece coated with the multiple organic composite films.

Example 3

1000ppm of triphenyl borate, 2000ppm of ethyl borate, 500ppm of benzoic acid, 1500ppm of ternary polycarboxylic acid, 1000ppm of diisooctyl sebacate, 200ppm of sodium citrate as film forming aid and 75ppm of rubidium nitrate as catalyst.

The components were stirred and dissolved in water, the pH of the solution was adjusted to 9.3, and pure water was added to a film-forming solution volume of 1000mL, to obtain a film-forming solution as described in this example.

(2) and (2) placing the steel sample pretreated in the step (1) in the film forming solution prepared in the embodiment, spraying for 18s at the normal temperature (15 ℃) to finish film forming, taking out the sample, and drying or naturally airing to obtain multiple organic composite films on the surface of steel, thereby obtaining the steel workpiece coated with the multiple organic composite films.

Comparative example 1

1700ppm of ternary polycarboxylic acid, 1000ppm of dibutyl sebacate, 150ppm of sodium gluconate film-forming aid and 50ppm of rubidium carbonate catalyst.

(2) and (2) placing the steel sample pretreated in the step (1) in the film forming solution prepared in the embodiment, immersing the steel sample in the film forming solution at normal temperature (17 ℃) for 60 seconds to complete film forming, taking out the sample, and drying or naturally airing to obtain a coating film on the surface of steel, thereby obtaining the steel workpiece with the coating film.

Comparative example 2

2500ppm of triisopropanolamine cyclic borate, 1000ppm of dibutyl sebacate, 150ppm of sodium gluconate film-forming aid and 50ppm of rubidium carbonate catalyst.

Comparative example 3

2500ppm of triisopropanolamine cyclic borate, 1700ppm of tricarboxylic acid, 150ppm of sodium gluconate film-forming aid and 50ppm of rubidium carbonate catalyst.

Comparative example 4

2500ppm of triisopropanolamine cyclic borate, 1700ppm of tricarboxylic acid, 1000ppm of dibutyl sebacate and 50ppm of rubidium carbonate.

Comparative example 5

2500ppm of triisopropanolamine cyclic borate, 1700ppm of ternary polycarboxylic acid, 1000ppm of dibutyl sebacate and 150ppm of sodium gluconate film-forming aid.

Comparative example 6

2500ppm of triisopropanolamine cyclic borate, 1700ppm of ternary polycarboxylic acid, 1000ppm of dibutyl sebacate, 150ppm of sodium gluconate film-forming aid and 50ppm of potassium carbonate catalyst.

Comparative example 7

The components were dissolved in water with stirring, and the solution was adjusted to pH 6.3 without pH adjustment, and pure water was added to a film-forming solution volume of 1000mL to obtain a film-forming solution as described in this example.

Example 4

The steel workpieces obtained in the examples 1 to 3 and the comparative examples 1 to 7 are detected and compared by the following experimental methods, and the following data are obtained:

as can be seen from the test results of the examples and the comparative examples, the components of the present invention have a synergistic effect. Wherein, the comparative examples 1 to 7 are the antirust liquid which lacks a certain component or does not reach the standard under condition control, and the antirust performance is poor. And the examples 1-3 are the aqueous antirust liquid of the invention, the antirust performance is obviously improved, and the long-term antirust purpose can be achieved.

Example 5

The steel workpieces obtained in examples 1 to 3 and comparative examples 1 to 7 were subjected to scratch testing to simulate inevitable scratching of the workpieces during transportation and storage.

The experiments were designed as follows:

according to the tool shown in GB/T9286-1998, a six-blade cutting tool is selected, the blade interval is 1mm, and each workpiece moves 3cm at a constant speed.

Then, the following experimental methods are used for detection and comparison, and the following data are obtained:

it can be seen from the test results of the examples and the comparative examples that the multiple organic composite films formed by the present invention can still maintain good anti-rust function under the scratching condition, because the perfect connection is formed between the films of the present invention by using boron as the center, the films of the present invention do not exist independently, but are organically linked together, and cannot be easily peeled off or penetrated, so that the steel is compactly protected, and the inevitable scratching of the workpieces during the transportation and storage process can be effectively prevented. And the comparative examples 1 to 7 are the problems that the coating film is seriously damaged under the scratching condition due to the lack of a certain component or the lack of the antirust liquid with the substandard condition control, and the effective protection cannot be provided, which often occurs in the conventional antirust agent.

Example 6

The aqueous antirust liquid suitable for organic composite film formation on the surface of steel prepared in the embodiments 1-3 and the comparative examples 1-6 is subjected to film formation, a sample is taken out and dried or naturally aired, then the international epoxy primer Intergard7500 of the organic polymer coating is sprayed, and the following data are obtained by the following detection and comparison through the following experimental methods:

serial number	Experimental methods	Technical index	Results
				Example 1	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	11
Example 2	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	10
				Example 3	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	9
Comparative example 1	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	2
				Comparative example 2	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	2
Comparative example 3	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	4
				Comparative example 4	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	3
Comparative example 5	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	3
				Comparative example 6	ISO 4624:2016	The adhesive force is more than or equal to 2.5MPa	4

As can be seen from the test results of the examples and the comparative examples, the components of the present invention have a synergistic effect. The comparative examples 1 to 6 are rust-proof liquids which lack a certain component or do not meet the standard under condition control, the bonding strength of the rust-proof liquids with a subsequent coating is low, and the coating is easy to fall off, so that the coating cannot achieve effective protection and has poor corrosion resistance. And the water-based antirust liquid disclosed by the embodiments 1-3 has high bonding strength with a subsequent coating, and the coating is not easy to fall off, so that the coating can play an effective role in protection, and the corrosion resistance is obviously improved.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. The water-based antirust liquid suitable for organic composite film forming on the surface of steel is characterized by comprising the following components in concentration:

1000 to 5000ppm of a boron-containing copolymer,

600 to 3000ppm of an organic acid having a ring structure,

500 to 1000ppm of a compound containing a polycarboxyl group,

50 to 300ppm of a film-forming aid,

50 to 100ppm of a catalyst,

the balance of pure water;

the film-forming assistant is an oxyacid alkali metal salt compound; the pH value of the aqueous antirust liquid is 8.5-9.5; the boron-containing copolymer comprises one or more of ethyl borate, triphenyl borate and triisopropanolamine cyclic borate; the organic acid containing a ring structure comprises one or more of benzoic acid and triprotic polycarboxylic acid; the compound containing the polycarboxyl compound comprises one or more of dibutyl sebacate, dioctyl sebacate and diisooctyl sebacate; the oxygen acid alkali metal salt compound comprises one or more of sodium citrate, sodium gluconate and disodium ethylene diamine tetraacetate; the catalyst comprises one or more of rubidium carbonate, rubidium sulfate and rubidium nitrate.

2. The aqueous antirust liquid suitable for the organic composite film forming on the steel surface as claimed in claim 1, wherein the aqueous antirust liquid further comprises the following components in concentration: 1000-2000 ppm of a pH stabilizer.

3. The aqueous antirust liquid suitable for organic composite film formation on steel and iron surfaces as claimed in claim 2, wherein the pH stabilizer comprises triethanolamine.

4. The aqueous antirust liquid suitable for the organic composite film forming on the steel surface is characterized by comprising the following components in concentration:

2500ppm of triisopropanolamine cyclic borate,

1700ppm of a tri-carboxylic acid,

1000ppm of dibutyl sebacate (DBP),

150ppm of sodium gluconate (sodium gluconate),

50ppm of a rubidium carbonate (Rb) in the form of a solid,

the balance of pure water;

5. The application of the aqueous antirust liquid suitable for the organic composite film formation on the surface of steel according to any one of claims 1 to 4 is characterized in that the aqueous antirust liquid is applied to the surface of steel for rust prevention to form an organic composite film.