Attentions of using epoxy resin fillers
Filler has become an essential part and the growth area of epoxy resin with the development of electronics industry and electrical industry. However, it also has some problems. Epoxy resin fillers are applied to seal electronic and electrical components in order to meet the requirements, such as insulation,anti-pressure and protection.
The specialists said that the problems are about defoaming technique of curing products, how to choose the hardener and how to fill. The specialist, coming from China Epoxy Resin Institute, introduces something about defoaming technique of curing products. Fillers have tack. With the increase of temperature, the viscosity of filler will increase and bubbles, producing by stirring, will burst. But some bubbles will not break during the manufacturing process. It is necessary to add defoaming agent and foam depressant. The quantity of foam depressant is very essential. If less, the bubbles will not break. If more, there are lots of oil and white mottle on the surface of curing materials. Nowadays, defoaming agent and foam depressant are made of silicone oil whose advantages are to produce irregular oil and grease on the surface of curing materials leading by false additive contents. So what the most important is adding methods, the types and amount of defoaming agent.
It is important to choose suitable hardeners according to different epoxy resin fillers. Hardeners are divided into low , medium and high temperature. Generally speaking, users can choose aminecuring agent, modified amine curing agent and polyamide curing agent in medium-low temperature, choosing anhydride agent in high temperature. According to the adhesive properties and working conditions, each hardener has different using proportion of epoxy resin filling system. With considering the difference between practical and theoretical values, users can calculate the proportion of pure epoxy in epoxy resin fillers according to the epoxy resin curing agent. Meanwhile, users can test the optimal curing temperature by a unit mass of curing system on the basis of the manufacturers’ data, the usage of products and heat of reaction.
Fillers is very important. The specialist, coming from China Epoxy Resin Institute, introduces that it is necessary to add some fillers to improve the physics intensity of curing products. Fillers include aluminum hydroxide, tabular spar, silicon micro-powders, french chalk and quartzsand. Some fillers have other properties of flame resistance and preventing precipitation.
Precipitation is very common during the filling process. Most fillers are hard to mix with organic materials because they are inorganic. Particularly long-term placement will cause the sediment of fillers. So the fillers have good effect with organic materials after organic treatment.