A self-healing water-based rusty coating primer was successfully developed, effectively solving the problems of insufficient response and sealing properties!

Introduction

With the continuous increase in the volume of China's industrialization and continuous investment in infrastructure and speeding up its construction, it has promoted the rapid development of the anti-corrosion coating industry and promoted the upgrading of various materials

When processing rusty substrates, it is often required to polish away the floating rust, leaving the black iron part, which is mostly α-FeOOH, which is generally hard and difficult to polish.

In this study, a water-based rusty paint primer that can self-heal to a certain extent was prepared to solve the above problems, and it can reduce the use of zinc, lead, chromium and other heavy metal elements in the paint, and reduce Costs and labor related to maintenance of civil and industrial coatings

1 Reaction mechanism of rust coating

In this project, a complex monomer synthesized by the reaction of an organic acid and propylene glycol is used, and a functional monomer of phosphate ester, methyl acrylate, butyl acrylate and other monomers are emulsified and synthesized.

2 Experimental part

2.

Self-made corroded carbon steel sheet (see Figure 1), C4 grade carbon steel (70 mm×150 mm×3 mm)

Figure 1 Effect of corroded surface

2.

The rust coating performance test results are shown in Table 1

Table 1 Test results of rust coating performance

3 Results and discussion

3.

For a single primer test, a variety of rust conversion primers on the market were compared and tested.

Figure 2 The rust conversion primer is resistant to salt spray for 48 hours and blisters appear on the board surface

Figure 3 The surface of the rust conversion primer after salt spray resistance for 300 h

Figure 4 1000 h salt spray test panel effect of 100 μm waterborne acrylic primer with rust

3.
2 Overcoating test

The overcoating test of various rust conversion primers found that the second primer could not be effectively applied after one reaction was completed, and the average anti-sagging effect of general rust conversion primers was not good, and it was impossible to achieve a single coat of 50 μm.
Above the dry film, this leads to a situation where the rust cannot be completely converted but cannot be remedied in the case of severe rust
.
The water-based rusty coating primer designed for this project can be applied in multiple passes, and can reach a wet film thickness of 200 μm or more, which improves the workability
.

3.
3 Self-healing test

，80 μm，，，
。，，
。，，
。，，7 d200，50 ℃，50%
。

3.
4

，1 mm，
。1，，
。0，、
。，，1000 h，45%，0，
。

Studies have shown that after the coating is destroyed, to a certain extent, the creep ability of the paint film and the re-entanglement of the multi-branched structure and re-complex and passivate the adhesion with the iron-based, make the paint film self-healing possible.
Effectively extend the life cycle of the paint film
.
The focus of current research is how to match with other paint films to adapt to the needs of different scenarios, to achieve high-efficiency anti-corrosion functions, and to evaluate the robustness of the coating system
.
In short, anti-corrosion coatings will inevitably suffer mechanical damage, micro-cracks and subsequent rust damage during use.
In the future, the understanding of rust protection and functional improvement will be further deepened, but at present, water-based rust coatings The research of the primer coating shows that the coating has excellent adhesion and salt spray corrosion resistance during use.
The temperature change self-healing property of the coating can resist the corrosion ability of micro-cracks to a certain extent, which can effectively extend Coating service life
.
Significantly reduces the cost of rust and anti-corrosion renovation, and reduces the downtime for maintenance of machinery and equipment and workshops in various industries, which has significant practical social application value
.