Usage and operation precautions of electronic potting compounds

There are many types of electronic potting compounds, and according to the material type, the three most commonly used ones are currently epoxy resin potting adhesive, organic silicon potting adhesive, and polyurethane potting adhesive. However, these three types of materials alone can be further divided into hundreds of different types and applications of products. Electronic sealing adhesive belongs to a liquid state before curing, with fluidity and viscosity of the adhesive liquid. The specific sealing adhesive operation varies depending on the material, performance, and production process of different products.

When using electronic potting compounds for electronic components, it is necessary to strictly control the environmental temperature, humidity, operating vacuum, temperature, and other influencing factors to ensure the success rate of sealing. Generally speaking, during the sealing process, it is required that the ambient temperature should not exceed 25 ℃. Otherwise, the prepared rubber material is prone to vulcanization and drawing in a short period, causing inconvenience to the sealing operation. The pre-drying temperature of the filler must be controlled at around 100 ℃, and the pre-drying time is about 4 hours so that the water molecules inside the filler can fully evaporate. Otherwise, it is easy to cause the residual water molecules, which can increase the surface conductivity of the insulation material, reduce the volume resistivity, increase the dielectric loss, and lead to problems such as short circuits, leakage, or breakdown of the electrical components.

If the sealed printed board is being sealed, the printed board needs to be cleaned before sealing and then pre-dried for moisture removal. The temperature and time for pre-drying and moisture removal can be determined based on the allowable temperature of the printed board assembly. The following temperatures can usually be selected: pre-drying temperature: 80 ℃, which takes 2 hours; Pre drying temperature: 70 ℃, which requires 3 hours; Pre drying temperature: 60 ℃, which requires 4 hours; Pre drying temperature: 50 ℃, requires 6 hours.

Precautions for electronic sealing adhesive dispensing:

1. Under the condition of bottom temperature, Agent A will crystallize. Before mixing, it is necessary to heat it at 40-50 degrees for 40 minutes.

2. The glue solution prepared each time must be used up within 25-30 minutes, otherwise the viscosity will gradually increase and the fluidity will deteriorate.

3. When using a dispensing cylinder that has been dispensed with glue again, the glue inside the dispensing cylinder must be cleaned thoroughly before continuing to dispense glue, otherwise, it is easy to cause filamentous substances and poor fluidity inside the glue.

Materials and tools required for sealing:

Two-component electronic sealing adhesive (A component silicone and B component curing agent), measuring mixing container (plastic, glass, and other compatible containers), gloves (soft things), electronic scale (accurate to 0.1g), vacuum machine.

Electronic sealing adhesive operation steps and precautions:

1. The sealed products need to be kept dry and clean;

2. When using the two-component electronic sealing adhesive, please first check Agent A to see if there is any settling, and mix Agent A thoroughly and evenly; the B agent is the same.

3. Measure correctly according to the correct mix ratio (weight ratio). If there is a significant error in the measurement of the mix ratio, the characteristics of the product will not be displayed well.

4. After mixing agents A and B, stir thoroughly and evenly again to avoid incomplete curing due to uneven mixing. A. Mix and stir agent B evenly. When mixing A and B glue, pour the less proportion into the more proportion and mix. When mixing, stir in one direction and not too fast, stirring for about 3 minutes. Stir the bottom and walls of the container evenly. If not stirred evenly, incomplete curing may occur in the later stage. The mixing container must be about three times larger than the mixing material.

5. Vacuum and remove bubbles. After complete stirring, quickly move to the vacuum box and de foam. The bubbles drawn in during stirring will cause the liquid level to rise, and after the bubbles break, the liquid level will drop again. The magnitude of vacuum degree and vacuum pumping time depend on the viscosity of the adhesive and the requirements of the product (the defoaming time is generally 2-4 minutes). If there is no vacuum machine, you can stir clockwise for 2-3 minutes. After stirring evenly, let the glue stand for 5-20 minutes to automatically defoaming.

6. After mixing evenly, the sealing adhesive should be poured in a timely manner. If the pouring operation time is too long, it can cause the sealing adhesive to solidify.

7. After pouring, it is best to shake the product so that the glue gradually penetrates into the gaps of the product, and if necessary, perform a second glue filling. After mixing, it will gradually solidify and its viscosity will gradually increase. Let it stand for a period of time and let it release bubbles.

8. Long term contact with adhesive can cause mild skin allergies and itching. It is recommended to wear protective gloves when using. If it sticks to the skin, please wipe it off with acetone or alcohol, and clean it thoroughly with a cleaning agent; Before entering the eyes, it is necessary to wash with clean water before seeking medical attention.

9. Before using it in large quantities, you can try it out in small quantities to master the product's usage skills and avoid errors.

Precautions for gluing:

1. If there is still adhesive on the surface of the product after curing, wipe the surface with a cotton cloth dipped in alcohol.

2. Try not to stick the adhesive to the surface of electronics or appliances. If it does, wipe it off immediately with a cotton cloth.

3. The equipment used for sealing should be cleaned regularly. If the pot body is used for gluing, it is necessary to ensure that there is no adhesive liquid that has already started to solidify inside the pot.

Storage and shelf life:

This product should be stored at room temperature for about a year, but the material must be resealed properly.