The surface treatment of the metal substrate plays an important role in the performance of the coating. The traditional surface treatment is divided into mechanical treatment and chemical treatment. Although the processes of phosphating and passivation in chemical treatment are mature, the waste water discharge and treatment costs are relatively high.

Ⅰ. Roles of silane coupling agents in metal pretreatment

At present, after the metal is pretreated with a silane coupling agent (SCA) and a phosphorus-free coating, it can not only improve the bonding force and anti-corrosion performance of the coating and the metal substrate, but also meet the environmental protection emission requirements.

The special structure of silane determines that it can form a chemical bond with metal (Si-O-Me, Me refers to metal), thereby improving the chemical bond between the coating and the metal substrate.

In recent years, the role of silane coupling agents in the pretreatment of anticorrosive coating metals has gradually been recognized. Its technological process is simple, the tire rubber additives are non-toxic, harmless, and non-polluting, have a wide range of applications, and have low overall costs.

Ⅱ. Structural formula of silane coupling agents: Y-R-SiX3

Y is a group capable of reacting with organic compounds, such as a vinyl group, an amino group, an epoxy group, and a mercapto group. The coating aid R is a carbon chain with saturated or unsaturated bonds. X is an alkoxy group, an acetoxy group, a halogen group, etc., which can undergo a hydrolysis reaction and generate Si-OH.

The reaction mechanism is:

1. The Si-X group connected with silicon is hydrolyzed to Si-OH;

2. Si-OH is dehydrated and condensed into Si-OH oligosiloxane;

3. The Si-OH in the oligomer forms a hydrogen bond with the OH on the metal surface;

4. During the heating and curing process, a covalent bond is formed with the metal along with the dehydration reaction.

The treatment process is as follows: degreasing-rinsing-rust removal-rinsing-silane coupling agent treatment-drying-coating.

At present, this new process is more and more recognized by customers, and the silane coupling agent application and occasions are becoming wider and wider.

Hubei Co-Formula Material Tech Co., Ltd. is a globally recognized ISO certified manufacturer and reliable supplier of organic silicon materials. Co-Formula has been involved in the silicone industry since its establishment, focusing on the production and sales of functional silanes, silicone oils, silicone polymers and additives.

Co-Formula's commercial products include isocyanate silanes, amino silanes, epoxy silanes, mercapto silanes, phenyl silanes, vinyl silanes, chlorosilanes, alkyl silanes, long-chain silanes, silane crosslinkers, dimethyl silicone oil, methyl Hydrogen silicone oil and double-end type siloxane. In addition to these general products, Co-Formula can also provide coatings and plastic additives, silicone polymers, and provide customized solutions for global customers. If you have any needs, please feel free to consult us.