C9 petroleum resin for paint anticorrosive paint

The synthesis methods of C9 petroleum resin for paint anticorrosive paint mainly include thermal polymerization, catalytic polymerization, and free radical polymerization, each of which has its unique process characteristics and applicable scenarios.

1. Thermal polymerization

Principle: Thermal polymerization is based on the Diels Alder reaction. In this process, the C9 fraction is heated to a certain temperature (usually around 260 ℃), and the two polymerizable molecules first form Diels Alder addition intermediates, which then react with the molecules of another polymerizable component to generate two free radicals, thereby initiating the polymerization reaction.

Characteristics: The thermal polymerization method has a simple process and high yield. However, due to the high reaction temperature, relatively high energy consumption, and easy occurrence of coking, the color of C9 petroleum resin for paint anticorrosive paint produced is darker and the product grade is lower. Therefore, in industry, thermal polymerization is mainly used to produce dark colored resins, which are mainly used as rubber reinforcing agents, concrete additives, etc.

2. Catalytic polymerization

Principle: Catalytic polymerization is a cationic addition polymerization reaction. Under the action of the catalyst, C9 monomer forms a carbocation active center, which then triggers chain polymerization and ultimately synthesizes petroleum resin. The type of catalyst has a significant impact on polymerization reactions, and commonly used catalysts include boron trifluoride (BFv3) or its ether complexes.

Characteristics: Catalytic polymerization is the earliest and most widely used method for synthesizing C9 petroleum resin for paint anticorrosive paint. It can react at lower temperatures, consumes less energy, and produces lighter resin colors with higher product quality. In addition, by adjusting the type of catalyst and reaction conditions, the molecular weight distribution and properties of the resin can be flexibly controlled.

3. Free radical polymerization

Principle: Free radical polymerization is the process of using a large number of unsaturated bonds (such as lone pair electrons) present in the C9 fraction to form free radicals under the action of initiators, and initiating chain polymerization. Common initiators include peroxides, sodium fatty acids, or their mixtures.

Characteristics: Free radical polymerization has the advantages of mild reaction conditions and easy control. By adjusting the type and dosage of initiators, the rate of polymerization reaction and the properties of C9 petroleum resin for paint anticorrosive paint can be flexibly controlled. However, compared to catalytic polymerization, the resin produced by free radical polymerization may have a wider molecular weight distribution and may contain some unreacted initiator residues.

4. Other synthesis methods

In addition to the three main synthesis methods mentioned above, there are also other synthesis methods used to prepare C9 petroleum resin for paint anticorrosive paint, such as the two-step process. The two-step process can simultaneously produce dark petroleum resins with higher softening points and light petroleum resins with lower color ratios, providing greater flexibility.
In summary, there are various synthesis methods for C9 petroleum resin for paint anticorrosive paint, each with its unique process characteristics and applicable scenarios. In practical applications, suitable synthesis methods can be selected based on specific needs and conditions.