Development of an environmentally friendly anti-corrosion primer

introduction

With the development of my country's national economy, the country has continuously increased its investment in infrastructure construction and accelerated its construction.
In this process, the construction of infrastructure has also led to the development of a series of industries and promoted the continuous progress and upgrading of various technologies.
With the improvement of infrastructure design requirements, the paint is facing new demands put forward new issues, particularly in terms of the life of corrosion protection coatings and coating properties of the material, the material of the season versatility and environmental friendliness such as com" href="http://">paint online coatingol.
com .

In this experiment, based on the research on the anti-corrosion mechanism of functional fillers, the functional fillers suitable for high-performance anti-corrosion resins are screened out, and the filler system is sought to improve the corrosion resistance of the coating through compounding to prepare an environmentally friendly type suitable for common substrate Anti-corrosion primer.

1 Experimental part

1.

Acrylic resin: self-made; talc, zinc phosphate, aluminum tripolyphosphate, scale zinc aluminum powder, corrosion inhibitor, iron red pigment, silicone oil, drier, HDI biuret curing agent, xylene, polyurethane paint thinner, etc.

1.

Electronic balance, sand mill, high-speed dispersing machine, oven, thickness gauge, salt spray resistance test box, damp heat box, etc.

1.

The basic formula is shown in the table below.

Basic formula

1.

In a clean sand mill, add acrylic resin, various pigments and fillers, and an appropriate amount of diluent according to the formula of component A.

1.

The base material of the sample plate is the oxidized aluminum plate and the polished galvanized tinplate.

Before spraying the sample, mix the A component and the B component according to the experimental ratio, stir well, dilute to a suitable spray viscosity, and cure for 10-20 minutes before using.

2 Results and discussion

2.

The chromium-free and cadmium-free anti-corrosion primer developed in this experiment, so avoid the use of fillers containing chromium and cadmium heavy metals, and the coating color is modulated by non-toxic pigments.
Anti-corrosion fillers for coatings were screened with talc powder, zinc phosphate, aluminum tripolyphosphate, and scale-type zinc-aluminum alloy powder as anti-corrosion fillers.
Four factors and three levels orthogonal test were used to determine the optimal addition amount of each filler.

Experimental Design Table

Experimental evaluation method:

After the paint film is made, evaluate its comprehensive anti-corrosion performance, including oil resistance, water resistance and salt spray resistance.
Choose the best experimental group to find the compound combination with the best corrosion resistance.

The test results show that the addition of flaky zinc-aluminum powder to the system can improve the anti-corrosion performance of the system, but it has an impact on the flexibility of the coating film and at the same time significantly reduces the adhesion of the topcoat.
The addition of zinc phosphate and aluminum tripolyphosphate to the experimental group Z5 has better performance, and the optimal ratio is 2% talc, 3% zinc phosphate, and 6% aluminum tripolyphosphate.

2.
2 Selection of Organic Corrosion Inhibitor

In this experiment, three corrosion inhibitors were selected and added to the anti-corrosion primer at a mass fraction of 1%.
Spray the prepared anti-corrosion primer on the substrate, and test its salt spray resistance and filiform corrosion after fully drying.
The experimental results are shown in the following table.

The influence of corrosion inhibitor on the anticorrosive performance of coating

The results show that the addition of corrosion inhibitor can effectively improve the salt spray and filiform corrosion resistance of the system, and the experimental group with corrosion inhibitor 1 has the best effect.

2.
3 Primer formulation design

The formulation design of the primer is carried out by orthogonal test method, and the experiment involves 5 factors: resin, pigment, anticorrosive filler, corrosion inhibitor, crosslinking agent (ie B component); each factor is designed with 4 levels.

Analysis of Orthogonal Test Results:

Result analysis method: The coatings prepared according to the orthogonal experiment (Z1-Z16) have different crosslinking densities and pigment-to-base ratios, so various basic properties are very different.
Evaluate their various mechanical properties (including adhesion, Hardness, flexibility, impact resistance), as well as water resistance, oil resistance, salt spray resistance, filiform corrosion and matching conditions with polyurethane topcoats, will be scored according to the technical indicators required by the project.
If there are unqualified items, it will be assessed as not.
Qualified (×).
For all qualified experimental groups, the best experimental group is the medium resistance and salt spray resistance, and the scores are excellent, good, and unqualified (×).
After analysis, the influence law of each factor on product performance and the best value of each factor are obtained.

Test result analysis: According to the scoring rules, the 16 groups of orthogonal tests were tested and scored.
The results showed that the Z13 experimental group had the best results.

2.
4 Comprehensive performance test

Based on the above research results, an environmentally-friendly anti-corrosion primer was prepared according to the best raw materials and their added amounts, and comprehensive performance tests were carried out.
The comprehensive performance test results are shown in the table below.

Comprehensive performance test results

Conclusion

(1) The environmentally friendly anti-corrosion primer prepared in this experiment uses non-toxic anti-corrosion pigments and fillers free of chromium and cadmium, which greatly reduces the contact toxicity of production and construction personnel and effectively improves the environment.
Not only meets the expected development goals, but also solves environmental problems;

(2) The anti-corrosion pigments and fillers and the new corrosion inhibitor compound technology used in the primer increase the salt spray resistance of the primer by more than 50%, reaching 3000h.

Authors | Sun Rui1, Liu Chen2, Huang Zhen1, etc.

(1.
Tianjin Dengta Coating Co.
, Ltd.
; 2.
Tianjin Public Technician College)