Panels hot-pressing

In order to increase the capacity of a production line, especially by shortening the panel hot press times, adhesive resins with a reactivity as high as possible should be used. This includes two parameters a short gel time and a rapid and instantaneous bond strength development, even at a low degree of chemical curing. 

Isocyanates by themselves cannot be used to bond plywood because of the characteristic balance of rheology and rate of hardening, which are characteristic of PMDl. However, recently, they have been used as minority additives (10-30%), copolymerized during panel hot-pressing with formaldehyde-based resins such as PF and even UF to yield very strong bondlines. These combinations have been used industrially to yield excellent bonding both in plywood and in particleboard. ... 

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