The most recently developed adhesive is the reactive hot melt moisture cured polyurethane adhesive (PUR). It is produced from a combination of different polyester and/or polyether polyols which react with an ecess of di-isocyanate to form pre-polymers with terminated isocyanate groups. These pre-polymers are thermoplastic and can be processed with gravature rollers, in the screen printing process or with slot nozzles. Typically, when this adhesive is applied at a temperature around 110 ~ 130¢XC, there is approximately one gram of water being absorbed by 100 grams of PUR in the curing process in order to achieve full cure. The adhesion attains its maximum capacity after complete cross-linking of the reactive isocyanate groups groups with moisture from the environment or substrates. These PUR adhesives are revolutionizing both textile and laminating processes so that many of problems of the aforementioned systems are overcome. Features include low cost, small batch size, ease of use and cleanliness, short start-up times, high-speed processing, versatility in terms of changeover, and ease of control of films and tensions, and coating add-on.

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