Industry dynamic

How to deal with the abnormal phenomenon of epoxy potting glue?

2022-11-23

When we usually use epoxy potting glue, if the operation is improper, it is very likely that the surface will become white, oily, pitted, printed, wrinkled, or pinholes after curing. Then we should encounter these abnormal phenomena. How to solve it?

1. Whitish

The phenomenon of whitishness is mainly reflected in the appearance of black or transparent epoxy potting glue, which is easy to appear due to obvious color difference. This phenomenon is more likely to occur in winter. The reason is that the temperature in winter is low, some users store at room temperature, and the time is longer, resulting in crystallization of the glue. Generally, crystallization does not occur in short-term storage at low temperature. In this case, as long as the precipitated components are heated and stirred evenly, the phenomenon of curing and whitening can be solved when used in compounding glue.

2. Oil/oil bloom

Oil on the surface is caused by excess curing agent. The curing agent is lighter than the main agent. After the epoxy potting adhesive AB is mixed, the B agent curing agent will be on the upper layer. Usually we require customers to mix the AB glue. Pour A into agent B, and then stir evenly to prevent the chemical agent from being stirred unevenly on the upper layer; under normal circumstances, epoxy potting adhesives are operated at a weight-to-star ratio, so customers are required to measure with an electronic scale Take it to prevent excessive curing agent, too much curing agent cannot react chemically, and the density is light, so it remains on the surface.

3. Pit

The formation of pits is caused by the fact that the glue cannot self-level after the air in the epoxy potting glue breaks open on the surface, so there are two reasons for the formation of pits, one is the slow defoaming speed, and the other is the curing speed Too fast, so starting from the product, it is necessary to comprehensively consider the defoaming speed to adjust the curing speed, and the second is to minimize the generation of bubbles in the glue, and use vacuum defoaming.

4. Printing

The surface printing of epoxy potting adhesive refers to the appearance of a piece of printing on the surface of the colloid after curing, usually accompanied by color differences. Such problems are directly related to the sensitivity of the curing agent and moisture. The control measures are the hygroscopicity of the curing agent and the humidity of the sizing environment. The probability of printing is greater, so epoxy potting adhesives have printing phenomenon, choose a curing agent with low hygroscopicity, or reduce moisture.

5. Wrinkling

Wrinkling of epoxy potting adhesive refers to the appearance of waves, unevenness and honeycombing on the surface of the colloid after curing. Most of these problems are related to the severity of curing. The more intense the product reaction, the shorter the effective self-leveling time, resulting in wrinkles that cannot be leveled and eliminated. The more the epoxy potting compound is mixed, the more violent the reaction will be. Therefore, for products with a lot of potting, you can choose multiple potting. In addition, in terms of its own performance, there is also a certain relationship between wrinkling and curing shrinkage.

6. Eye of the needle

 Epoxy potting glue pinholes refer to the densely raised needle points on the surface of the glue after curing. This kind of problem is related to air bubbles. The formation of pinholes is that the small bubbles will break open in the future during the discharge process, and the colloid will thicken and solidify. Therefore, to solve the problem of pinholes, we need to solve it from three aspects. One is to prolong the curing time, and the other is to It is to improve the defoaming property of epoxy potting glue, and the third is to carry out vacuum defoaming treatment before use.