What are the factors that affect the curing speed of potting compound

Potting compounds are generally liquid or paste-like, and these adhesives need to be cured before they can exert their bonding effect during bonding. Therefore, the curing process of adhesives is also very important. If the curing is not good, the impact on the bonding of items is very large, even if the adhesive you use is even better, it may affect the bonding effect.

The curing of potting compounds is generally divided into initial curing, basic curing, and post-curing. Curing reaction is the process of obtaining and improving bonding strength and other properties through chemical reactions (polymerization, cross-linking). Curing is the key process to achieve good bonding performance. Only when fully cured can the strength be maximized. The three curing methods are as follows:

1. Initial curing: Under certain temperature conditions, after some time, reaching a certain strength, the surface has hardened and is not sticky, but the curing is not complete.

2. Basic curing: After some time, most of the reaction groups participate in the reaction and reach a certain degree of cross-linking.

3. Post-curing: To improve the bonding performance or meet the needs of the process, the treatment of the basic cured adhesive is generally carried out at a certain temperature and maintained for a period, which can supplement the curing, further improve the degree of curing, and effectively eliminate internal stress and enhance the bonding strength.

To obtain a well-cured adhesive layer, the curing process must be carried out under appropriate conditions. The curing process of adhesives has a significant impact on the quality of bonding. Our company's adhesives are operated according to weight ratios. In addition to the main factor of uneven weight ratios, there are three basic process parameters during curing: temperature, pressure, and time. These three parameters also have a significant impact on the curing of adhesives.

The three major factors affecting adhesive curing:

1. Curing time

Curing time refers to the time required for the bonding process to cure under certain temperature and pressure conditions. Different adhesives also have different curing times, such as instant curing, such as a-cyanoacrylate adhesive, hot melt adhesive, which can cure for several hours, such as room temperature fast curing epoxy adhesive, and several days of curing, such as epoxy polyamide adhesive. The curing time is also affected by the curing temperature and pressure. Increasing the curing temperature can shorten the curing time. Under lower curing temperature conditions, the curing time needs to be greatly extended. If it is lower than room temperature, it may not cure for several days.

2. Curing temperature

Curing temperature is one of the important parameters during adhesive curing. If the curing temperature is too high, it can easily cause the loss of adhesive or embrittlement of the adhesive layer, leading to a decrease in adhesive strength, If the curing temperature is too low and the molecular chains of the matrix are difficult to move, it will cause the crosslinking density of the adhesive layer to be too low and the curing reaction cannot be completed. Therefore, during the curing process, the curing temperature must be strictly controlled, and each adhesive has a specific curing temperature.

3. Curing pressure

Curing pressure refers to the application of a certain amount of pressure during the curing process, which is conducive to the good bonding between the adhesive layer and the adherend, ensuring quality. Due to the different types of adhesive, the applied pressure is also different, generally divided into the following three situations: contact pressure is the pressure generated by the weight of the adherend for curing, without the need for additional pressure, such as epoxy resin adhesive. The pressure range of 0.1~0.3MPa is suitable for solvent-based adhesives, such as phenolic formaldehyde formaldehyde adhesive, phenolic nitrile adhesive, epoxy nitrile adhesive, epoxy nylon adhesive, and polyimide adhesive. The pressure range of 0.3~0.5MPa is suitable for various adhesives such as film, powder, tube, and particle, as well as hot melt adhesives. The purpose of increasing the pressure is to improve its wettability.

Although the quality of the adhesive is important, the curing factors cannot be ignored. No matter how good the adhesive is, if the curing temperature, pressure, and time are not taken into account, it will have a significant impact on the adhesive performance. It may lead to factors such as weak adhesion of items and prolonged noncuring of adhesives, so it is important to pay attention to these factors when using adhesives.