Abstract: A process of forming a multi-ply laminate which comprises at least one ply 2 of thermoplastics material forming a transparent outer ply of the laminate, such process comprising assembling the plies 1, 2 of the laminate, degassing its inter-ply space or spaces and subjecting it to bonding conditions including environmental laminating pressure distributed over the outside of the or each said thermoplastics outer ply 2 by a moulding plate 3 is characterised by the steps of:enveloping at least the edges of the assembled laminate plier 1, 2 and moulding plate(s) 3 by means 4 defining therewith an edge space 5 in communication with the inter-ply space(s),reducing the pressure P5 within the edge space 5 to commence degassing of the assembly and heating the assembly (curve T) while the main faces of the assembly are subjected to at least atmospheric environmental pressure P6 and subsequently, while the assembly is subjected to environment laminating pressure P6raising the edge pressure P5 to reduce or eliminate any d

Abstract: A hollow panel is prepared by uniting vitreous sheets by a spacer of synthetic polymeric material between the sheets. Preferably the polymeric material is a mixture including two polymers of substantially different molecular weight. A ribbon made of the polymeric composition is also disclosed.