Pattern to control spread of adhesive during lamination of sheets

Abstract

A first sheet (10, 32, 56) is coated by a coater (47) with a pattern comprising a plurality of discrete domains (12, 34) of a low-viscosity adhesive and is then laminated to a second sheet (70) by a paired-roller laminator (62). The viscosity of the adhesive is sufficiently low and the pressure of the laminator sufficiently high that the plurality of adhesive domains (12) are caused to spread during lamination and to displace air from between the sheets, forming thereby a single domain of adhesive which just fills the space between the sheets without adhesive being extruded substantially beyond the edges of the sheets and without air bubbles or voids being entrapped between the sheets. In a preferred pattern, the domains (12) comprise stripes of adhesive with spaces (14) therebetween, the stripes being substantially parallel to the direction of lamination (16). The stripes can be joined by a connecting domain (20) at the leading edge (18) of the first sheet to enhance lamination near that edge, and can be notched or indented (28) at their distal or trailing ends to smooth the adhesive front at the completion of the laminating pass. Preferably, the adhesive is radiation curable, allowing relative movement of the two sheets if desired after laminating, and the adhesive in the single domain then is cured by exposure to appropriate radiation. The method is especially suitable for laminating a lenticular overlay sheet to a lineiform image sheet in forming a lenticular depth image print.