Several reasons to be clear about petroleum resin

(1) Curing agent

Because of the different curing agents, it can directly affect the bonding process and the performance of the mechanical and electrical aspects after curing. Therefore, when petroleum resin is first used as a binder, it is very important to choose different curing agents according to the required process conditions. After curing, the performance requirements are not high and can be cured at room temperature. Amine curing agents can be used. At present, amine curing agents are still used more.

Commonly used are ethylene diamine, diethylene triamine, polyethylene polyamine and so on. Amines also have heating curing agents, such as m-phenylenediamine. If good heat resistance and chemical resistance are required after curing, an acid anhydride curing agent can be used, but the acid anhydride curing agent needs to be cured at a high temperature, and the amount is relatively large. Commonly used are maleic anhydride, phthalic anhydride, internal methine tetrahydrophthalic anhydride and so on.

In addition, after the resin is cured, there are other different requirements, and various curing agents can be used. For example, if high mechanical strength is required after curing, urea-formaldehyde resin and melamine-formaldehyde resin can be used as curing agents. For another example, nitrobacteric anhydride that requires flame resistance after curing can be used as a curing agent.

(2) Curing degree

When the same curing agent is used to bond the same object, the shear strength after curing may be very different. The reason is that the curing conditions are different. That is, after curing, the curing with high bonding strength is relatively complete, and vice versa, the curing is incomplete. In order to achieve better performance, it is necessary to cure the resin as completely as possible, that is, to extend the curing time. For example, when the amount of flag material is large (*** or above ***), in order to obtain strong shear strength, it needs to be cured at room temperature for a few days.

(3) Adhesive glue line

It is generally believed that the thickness of the glue line should be thinner. When the thickness of the glue line is increased to a certain level, some abnormal phenomena will occur.

(4) Curing pressure

The pressure during curing should be sufficient to ensure complete wetting of the adhesive and even distribution on the bonding surface. For the bonding between the curing agent (or adding diluent) and other auxiliary agents, the contact pressure during bonding is generally sufficient. For bonding with other auxiliary agents, the contact pressure during bonding can be increased appropriately to strengthen the bonding strength, but the pressure cannot be so high that it damages the glue line, so the selected pressure should be able to fully maintain the initial curing time state.

(5) Adhesive materials

Adhesives based on petroleum resin have excellent bonding properties to many metal materials such as steel, inscription, copper and so on. It has good bonding properties to most thermosetting plastics (phenolic plastics, drunk plastics, etc.) and non-metallic materials such as glass, wood, concrete, paper and cloth. However, it has poor adhesion to most plastic products (celluloid, polyvinyl, polystyrene, etc.), especially for silicone resin, silicone rubber, and silicone oil.