Production Method and Characteristics of Silica gel for Gypsum Products

Apr 25, 2021

Characteristics of silica gel for gypsum products
①Gypsum products silica gel should have good operation performance.
②Silicone has better fluidity, low viscosity and easy operation.
③The smaller the shrinkage rate of silicone rubber, the better.
④The tensile force of silicone rubber is better.
⑤The made silicone mold cannot be deformed.
⑥The hardness of silicone rubber should be suitable for product use.
⑦High temperature resistance, many times of mold turning, the longer the service life, the better, acid and alkali resistance and aging resistance.

Production Method
1. Use a plastic bowl to hold 500g of glue, add 1.5% curing agent at room temperature, and stir well for later use.
2. Treat the master mold blank with a release agent to lubricate.
3. The lubricated master blank is surrounded by wooden strips, and the wooden strips should also be treated with a release agent, and the gap between them should be 2-4 cm.
4. Pour the prepared glue slowly along a fixed pouring point, shaking from time to time to remove the air inside.
5. After the glue is cured in 60 minutes, surround it with wooden strips, leaving a gap of 4cm, and remove the log strips.
6. Pour 1000g of gypsum powder into the wooden frame until it is full (the wooden frame should be divided into two parts with plastic sheet to facilitate mold removal).
7. Remove the wooden strips after 20 minutes, and the mold will be completed.

Note:
1. The amount of curing agent added should depend on the temperature, and it will decrease if the temperature is higher. If the curing agent is used too much, the mold will become hard and brittle; if the curing agent is used too little, the operating time will be prolonged.
2. In order to prevent changes in the physical properties of the mold silicone, it is recommended not to add silicone oil.
3. In order to achieve the best use of your mold, please store the mold for at least 24 hours before use.
4. The hard mold can also be made of resin.

The operation method of gypsum products silica gel:
1. Stir the silicone and curing agent evenly. The appearance of mold silicone is a flowing liquid, component A is silica gel, and component B is curing agent. Example: Take 100 grams of silica gel and add 2 grams of curing agent. (Note: The silicone and curing agent must be stirred evenly. If the mold is not evenly stirred, one part of the mold will be cured, and one part will not be cured, and the silicone will dry and cure unevenly. It will affect the service life of the silicone mold and the number of mold turnovers, and even cause the mold to be scrapped.
2. Vacuuming and degassing: After the silica gel and curing agent are evenly mixed, vacuum and degas the bubbles. The vacuuming time should not be too long. Under normal circumstances, it should not exceed ten minutes. If the vacuuming time is too long, the silica gel will be immediately Curing produces a cross-linking reaction, which makes the silica gel become piece by piece and cannot be brushed or poured. This wastes the silica gel. You can only pour the silica gel into the trash can and take the silica gel again to make it.
3. Brushing or operation process: the silica gel that has been evacuated and drained of bubbles is brushed or poured. Pour it on top of the product (Note: The product or model to be copied before pouring the silica gel must be coated with a release agent or release agent). Then apply the silica gel on the product. The application must be even. After 30 minutes, paste a layer of gauze and weft cloth to increase the strength and tensile force of the silica gel. Then apply a layer of silica gel, and then paste a layer of gauze fiber weft cloth, so that it will be fine after two times. Only by doing so, the service life of the opened silicone mold and the number of turning molds will be relatively increased, which can save costs and improve efficiency.
4. The production of the outer mold: The generally used method and material is to surround the mold with rubber sheets or wooden boards. Once the mold cabinet is filled with plaster, it is enough to use the resin painting method, painting Paste a layer of glass fiber cloth on one layer of resin, brush and paste, and repeat two or three layers to complete the outer mold of the mold.
5. The operation method of filling mold or pouring mold: filling mold or pouring mold is used for relatively smooth or simple products. There is no mold line to save labor and time, which is to use plastic sheet or glass for the product or model you want to copy. Surround the board, pour the vacuumed silica gel directly onto the product. After the silica gel is dried and formed, take out the product and the mold is formed. (Note: The infusion mold generally uses softer silica gel as the mold, so that it is easier to demold. , Will not damage the product inside the silicone mold).