Selection method of release agent
Due to the fact that most liquid release agents are acidic, the following issues should be noted during use:
1. The use of acid sensitive pigments can cause color changes;
2. When using alkaline fillers such as calcium carbonate, acidic release agents will react with them, causing an increase in the viscosity of the mixture, but it will not affect the release effect;
3. If the filler is aluminum hydroxide, the acidic release agent will not only increase the viscosity of the mixture, but also release water during the solidification process of the mixture, causing problems such as bubbles and cracks.
Usually, the initial dosage of internal release agent is 1% of the resin content, and the effective addition range is based on the weight of the resin at 0.75-2%. Adjustments should be made according to the actual situation.
1. Thin walled simple profiles can be used in small quantities, such as 0.8% or less;
2. Thick walled or complex shaped profiles need to be added more.
3. In high filler systems, the amount of internal release agent added should be increased, but excessive addition of internal release agent can delay curing.
4. In extrusion production, if the resistance is too high and the cause cannot be found, it is necessary to increase the amount of release agent appropriately. When using, attention should be paid to the order of adding materials. Before adding curing agents, fillers, and other resin additives during mixing, the internal release agent should be added to the resin system and mixed evenly. This can achieve the best demolding effect.