Molded foam molding
DATE：2021/12/1 8:42:49 / READ： / SOURCE：This station
Molded foam molding
Polyurethane molded foam can be applied to the molding of soft, semi-rigid, and rigid foam products. It is a very common foaming process. It differs from other moldings in that the casting material foams in the metal mold. Therefore, the influence of mold temperature, structure, thickness, and mold release agent on the process of mold foaming must be considered.
Molded foam is to mix various liquid raw materials uniformly through a stirrer, pour them into a mold to complete the foaming, and post-curing treatment to make a foamed plastic product that is the same as the mold cavity. The advantages of molded foam products are that they can be made into molded products with complex shapes, comfortable to use, and economical, and can reduce the waste of manpower and leftover materials. They are especially suitable for the production of furniture, automobiles, airplanes and other seat and cushion materials.
1. Production process
The metering pump mixes the various liquid materials uniformly through the mixing head according to the formula ratio, and then quantitatively injects them into the mold, performs reaction foaming in the mold, and takes out the molded foam product after maturation.
Compared with block foaming production, molded foaming does not require cutting processing, has less scrap loss, and has high labor productivity. It is conducive to automated production and has low manufacturing costs. It is especially suitable for products with large batches and complex structures.
2. Formulation
The formula of the molding foaming process is basically similar to the block foaming process in principle, except that most of the polyethers used in the polyether molding formula are highly reactive poly(polyethers with higher primary hydroxyl content). ), it can not only shorten the molding and curing time, but also the obtained foam product has a higher compressive load value. Although difunctional polymerization makes foam products have higher tensile strength and elongation, the coagulation speed and curing speed are relatively slow, so it is generally rarely used alone. If necessary, it can be mixed with polyethers with high functional groups. Currently used Most of the polyethers of flexible foams are trifunctional polyethers.
Compared with the block foaming formula, the amount of silicone foam stabilizer needs to be slightly increased or a foam stabilizer with better performance is used to increase the stability of the foam when manufacturing smaller density products. The foaming formula of polyether heat-curing and molding flexible foam.
Author：admin