LM Series Silica Anti-corrosive Pigment

Lingwe Technology LM series Ion-exchanged Anti-corrosive Pigment is a new kind of anti-corrosive

pigment focusing on current and future requirement. It is widely used in appliance coil coatings. As the environment regulation is becoming stricter and stricter, the heavy metal anti-corrosive

pigment such as chromate will be expelled from the market. And the non-toxic and harmless silica anti-corrosive pigment will be the superstar in the industry.

Theory

Lingwe Technology LM series ion-exchanged anti-corrosive

pigment is based on amorphous silica synthesized by special technology. In the process of synthesis, calcium and magnesium are mixed to do exchange with silicon hydroxyl group on the surface of amorphous silica, after this, it comes to get the new anti-corrosive pigment.

Without any heavy metal ions and phosphate ions, these kind of materials can cope with any future environmental policies and regulations. Now we take the LM 30 as example to introduce the theory of ion-exchanged

silica anti-corrosive pigment. Corrosion of all iron-based substrates, including galvanized surface treated iron-based substrates, are results from two electrode reactions.

Anode: Iron atom is effected by attack ion like the chloride ion, it will lose 2 or 3 electrons and become ferrous ion or ferric ion.

Cathode: The oxygen and water permeate the coatings film and combine with the electrons on the surface of substrate to form hydroxide ion. Ions move in the coatings film, eventually creating the hydroxide and oxide of iron, causing the substrate to rust.

LM 30 has high specific surface area, it can absorb the attack ions while dispersed in the coatings film which can postpone the generation of ferrous ion or ferric ion in positive pole.

Also, silica will dissociate and release silicate ions in alkaline condition. When the cathodic reaction occurs and the alkaline increases, it will consume the hydroxide ions and release the silicate ions. Silicate ion, calcium ion, ferrous ion or ferric ion will react and create the insoluble silicate, cover the surface of the cathode and the anode to form a passivated protective film, thereby blocking the occurrence of the reaction between the anode and the cathode. Therefore, LM 30 achieves anti-corrosive property from both physical and chemical aspects.

Advantage of LM30

LM 30 has not only the advantages of environmental friendly, but also advantages of product performance as below:

1. Good Dispersibility

While using the anti-corrosive pigment, the phosphate type need to be ground to achieve the qualified fineness and come to be anti-corrosive. Ion-exchanged

type like LM series just need to be dispersed in high speed without grinding, then can achieve excellent appearance affect and anti-corrosive property. Good dispersibility can make the coatings formulation easier to be adjusted, and it is easy to get the test data of anti-corrosive

performance and dosage, then help chemists to design the formulations to meet the market requirements.

2. Excellent Salt Spray Performance

LM has better salt spray performance than phosphate type, especially in water-based system that can improve the coatings film salt spray performance. Below chart is the comparison result of different anti-corrosive pigment with 5% dosage in water-based epoxy system.

Substrate: Steel

Test method: Spray

Thickness of film: 50~60 μm.

5% salt water spray.

From the chart, we can see LM30 is doing better than phosphate type. We estimate that ion-exchanged anti-corrosive

pigment LM30 can gain one more year efficiency than phosphate type in indoor coatings, and more half year in outdoor coatings.

Test Result by Different Items

3. Little Effect to Coatings Appearance

Silica has better transparency than common filler, LM30 adopts special synthetics process and surface treatment to make the pore volume less than 0.5 ml/g. LM30 has concentrated pore which is very close to a ball on microstructure, so it will not generate matt effect as other common filler. Due to better transparency, LM30 has nothing to do to the gloss and color in pigmented coatings. For users, it can avoid the color difference trouble due to different dosage of anti-corrosive pigment. Using silica anti-corrosive pigment can guarantee the coating film build by its strong gloss retention.

Applications:

- Appliance panel

- Powder coating

- Coil coating

- Engineer machinery

In the future, Lingwe Technology will keep focusing on the research and promotion of the environmental-friendly & harmless anti-corrosive

pigment. At present, this type of product do not show the better advantages than phosphate product in solvent-based system. And the architecture coatings will be mainly solvent-based for a long time. In response to this situation, Lingwe Technology will keep on studying the modified product to meet different requirements and we have already achieved great progress. We believe the new product will be coming soon. On the other hand, Lingwe Technology will respond to different environmental policy, think highly of the effect of product to the environment.We hope to meet customers’ latest and challenged requirements and provide the best materials and sustainable function by improving our product.