3 сентября, 2015 
Malyar Edge veneering requires use of a hot-melt adhesive that is relatively high in viscosity at application temperatures (usually around 200°C). The reasons for this are as follows:
1. The adhesive must have sufficient body to prevent flowing from vertical surfaces after application.
2. It must not penetrate the substrate surface too deeply, causing glue starvation.
3. It must have easy spreading and excellent wetting characteristics.
Viscosities of these hot melts are on the order of 50,000 to 60,000 mPas (cP) at 200°C. Viscosity is achieved through the correct selection of ethylene-vinyl acetate (EVA) copolymer grades, coupled with the quantity and type of reinforcing filler that is added to the system. The ball and ring softening point is an early indication of the degree of heat resistance of a particular hot melt. The softening point is influenced by the combination of ingredients, but to a large extent by the grade and quantity of EVA copolymer and tackifying resin contained in the system. Using a 5.1-g lead ball, the average softening points are between 90 to 105°C.
For optimum adhesion, the wetting characteristics (of the hot melt to substrates during application) are vital. Proper wetting is related to viscosity but is again largely influenced by resin selection and quantity. Stability of the adhesive is another important consideration. During prolonged periods at elevated temperature while contained in the hot-melt applicator, the hot melt must resist oxidation and thermal breakdown of components. This often leads to discoloration, charring, and inferior bonds. As a result of charred material, nozzle blockages can also be encountered.
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