The adhesion between CPUE and metal is involved in most polyurethane casting products, such as cots, solid wheels, coupling, ceramic mold, lining plate, sieve plate, etc.

Excellent adhesion strength can be obtained if proper adhesive is used in the adhesion between CPUE and metal. At present, NA-1 polyurethane adhesive (chem-lock218, 219 (produced by Shanxi Chemical Research Institute) (Shanghai Luode Chemical Co., Ltd.); conapll46, 1146c (CMAP company); thixon422, 423 can be selected for polyurethane elastomer metal transition adhesive (Rohm & Haas), xibang 45.48.49, etc

In order to obtain the ideal bonding strength, in addition to selecting a good adhesive, the whole bonding process must be carefully operated. Firstly, the metal is roughened with sandpaper or sandblasted (shot) to make the surface rough, so as to expand the bonding area and activate the surface. Then, it is deastered in trichloroethylene or toluene cooling tank (the effect of deacetylation in trichloroethane evaporation deaster tank is better) and dried. Next, the adhesive shall be bonded according to the standard rubber metal bonding procedure or the method recommended by the adhesive manufacturer (it is not recommended to use the technology of one-time application of adhesive). The adhesive with a certain thickness shall be coated or sprayed with a brush, and the solvent shall be fully volatilized. Finally, preheat the metal, and then wind the polyurethane compound.

To make the product easy to be removed from the mold without damage, release agent should be used = special care should be taken when using the release agent. It is generally not recommended to use silicone oil to avoid extrusion of release agent on the interface between metal and CPU elastomer during pouring, which will affect the bonding strength. When pue is poured onto the metal, with the vulcanization of the product, the adhesion strength between CPU elastomer and metal is also improved. When the product is just removed from the mold, the bonding strength is relatively low, so it must be operated carefully.

As far as bonded products are concerned, some need to be molded, while others are not.

And for molded products, it is particularly important to master the mold closing time. Too early, there are bubbles in the product; too late, it is easy to crush the glue or cause the flash to be too thick, which is not conducive to bonding. In addition, when the products are demoulded, the mold temperature is also high, and the bonding strength is low. Therefore, for rubber roller and rubber wheel products, it is much easier to reduce the mold temperature before demoulding, so that the rubber layer shrinks and then demoulds.