Aluminum hydroxide is used as a flame retardant in thermoplastics.
1. Application in epoxy resin
In epoxy resin, it has a good flame retardant effect. The dosage is 40%~60%. The oxygen index is twice as high as that of unfilled epoxy resin. At the same time, it also enhances the arc resistance. The epoxy resin filled with aluminum hydroxide is used in the manufacture of transformers, insulating equipment, switchgear, etc.
2. Application in unsaturated polyester
In glass fiber reinforced unsaturated polyester cast plastics (such as various high-voltage or low-voltage electrical switches), aluminum hydroxide is used as a filler to make plastic products have flame retardancy, smoke suppression, and arc resistance. It is also used in FRP laminates, such as FRP tiles, pipes, storage tanks, etc., with good flame retardant effects.
3. Cross-linked polyethylene, application in cables
In these polymers, the flame retardancy is improved due to the filling of alumina trihydrate, and it has excellent electrical insulation properties.
4. Application in polyvinyl chloride
In polyvinyl chloride, it can replace calcium carbonate filler and is easily incorporated into plasticized PVC. There are two ways to achieve high standards of flame retardancy: one is to use aluminum hydroxide and phosphoric carboxylate plasticizer together, and the other is to use it with zinc borate. These formulas have been applied to PVC wire and cable materials. Adding it to the hard PVC is mainly used as a smoke suppressant.
5. Application in latex and adhesives
Latex rubber and carboxylated latex adhesive for carpet padding were the initial applications of aluminum hydroxide. It also replaces calcium carbonate and clay with low flame retardancy in pre-coating, adhesives, and foam materials as flame retardant fillers. Generally, 100 parts of latex plus 20 to 150 parts of aluminum hydroxide with a particle size of 3 to 20 μm, and 75 to 250 parts of the binder.
6, polyethylene, polystyrene, ABS, and other thermoplastic applications
Aluminum hydroxide has been used in calcium-plastic panels for flame-retardant decoration and has achieved good results. However, in these thermoplastic materials, the additive amount when used alone must reach more than 60% to show a certain flame retardancy, and the impact strength of the plastic will be seriously affected. Therefore, its application in these thermoplastics is still a subject of continued research.
7. Application in synthetic rubber
Aluminum hydroxide is a good flame retardant in synthetic rubber such as styrene-butadiene rubber and neoprene.