Epoxy resin sealantWhat are the common questions? Recently, many customers have been inquiring about epoxy resin sealant, often raising questions such as the epoxy sealant they used not curing for a long time, or some parts have cured while others have not. The advanced technology editor has collected the following common problems and solutions for everyone.
Answer to the problem of epoxy resin sealant:
1. Dehydration does not cure, the cured resin is too soft, and the surface is too sticky. The fundamental reason is that it has not been completely cured, usually caused by inaccurate or uneven mixing ratios of the two components;
a) Inaccurate or arbitrary weighing: Sometimes excessive curing agent is added to accelerate the curing speed. In general, the amount of curing agent added should not exceed 5% of the mixing ratio. At the same time, special attention should be paid to whether the mixing ratio is a volume ratio or a weight ratio, and it should not be confused. The typical method of material retrieval is to place the container to be filled on an electronic scale and zero it, then weigh the required resin and curing agent as needed.
b) In adhesive with fillers, the main agent is not stirred evenly before mixing. Most resins are added with different additives to meet the predetermined requirements, and in most cases, there will be varying degrees of precipitation. Therefore, before use, it is necessary to thoroughly mix the main agent before extracting the required amount of resin. If the main agent is not stirred evenly or reacts with the curing agent and other chemicals (such as solvents, release agents, oils, or other incompletely cured main agents), this will also affect the curing effect. In order to ensure uniform mixing, the recommended mixing time for manual mixing is 10-15 minutes, and attention should be paid to the strength of the mixing to avoid introducing air into the resin as much as possible.
2. Curing time too long:
If this problem occurs under the premise of accurate proportion and uniform mixing, it is highly likely to be caused by too low curing temperature. One of the characteristics of two-component sealant is that it is greatly affected by temperature. The higher the temperature, the lower the viscosity of the adhesive and the faster the curing speed. Conversely, the lower the temperature, the longer the curing time.
3. The presence of bubbles after solidification is due to the gas not escaping or dissipating from the liquid adhesive;
a) The longer the curing time, the lower the viscosity of the colloid, and the easier it is for bubbles to overflow from the liquid glue. Preheating the product to be sealed will help with the escape of air. Reduce the curing temperature appropriately to allow sufficient time for the air to escape.
b) Like polyurethane sealant, due to its short curing time, it is prone to producing bubbles. If vacuum is not applied, it is highly likely to produce bubbles. It is recommended to evacuate the main agent and curing agent before mixing them together. If conditions permit, vacuum can also be applied after stirring.
4. Some adhesives have solidified, while others have not solidified or have not fully solidified?
Reason: Uneven mixing, A glue has been stored for a long time without being stirred or not stirred evenly before use.
5. What is the reason why epoxy sealant, which should have been a hard adhesive, becomes soft after curing?
Reason: Incorrect glue ratio: If the glue is not proportioned according to weight or there is a large deviation (this may occur if there is too much or too little curing agent), A glue may be stored for a long time without being stirred or stirred evenly before use.
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