초록 ▼

A method of uniformly applying a foamed adhesive to a normally moving substrate which is subject to stops and starts at irregular intervals. A uniform spread weight of adhesive is applied during a deceleration period and startups can be accomplished without causing puddles or gaps. The method is esp

A method of uniformly applying a foamed adhesive to a normally moving substrate which is subject to stops and starts at irregular intervals. A uniform spread weight of adhesive is applied during a deceleration period and startups can be accomplished without causing puddles or gaps. The method is especially useful in conjunction with an automated plywood lay-up line. Foamed adhesive is supplied under pressure to an extrusion head. When a line stoppage is sensed a first valve above the extrusion head closes. Adhesive within the head continues to expand and fall onto the substrate, but does so at a descreasing rate during the deceleration time. As the substrate comes to a complete stop a second valve prevents further adhesive from being applied. Before a startup, the adhesive in the system is reconditioned by passing it into a recycle line until foam quality andpressure drop across the extrusion head have again assumed normal operating parameters. Only then is the substrate movement started. At that time application of adhesive is resumed.

대표청구항 ▼

A process for applying a uniform amount of a foamed adhesive to a substrate normally moving at a uniform rate of speed but subject to stops and starts at irregular intervals which comprises: a. extruding a predetermined amount of the foamed adhesive from an extrusion head onto the moving substrate;

A process for applying a uniform amount of a foamed adhesive to a substrate normally moving at a uniform rate of speed but subject to stops and starts at irregular intervals which comprises: a. extruding a predetermined amount of the foamed adhesive from an extrusion head onto the moving substrate; b. sending a signal to stop the conveyor line moving the substrate, simultaneously closing a first valve to cut off the supply of foamed adhesive to the extrusion head, said valve being located in the foamed adhesive supply line in the proximity of the extrusion head so as to define a predetermined volume of foamed adhesive remaining under residual pressure in the head; c. permitting the foamed adhesive remaining in the extrusion head to continue to flow onto the decelerating substrate from the action of the retained pressure so that it is applied at a decreasing rate as the residual pressure in the extrusion head drops; and d. at approximately the time when the substrate has decelerated to a complete stop, closing a second valve located at a point in the extrusion head system where the foamed adhesive is at essentially atmospheric pressure in order to stop any further flow of adhesive onto the substrate so that during the deceleration period the substrate receives an essentially uniform spread weight & foamed adhesive without overspreading or creating adhesive free gaps.