Laminate material

Abstract

A self supporting curved laminate product resulting from curving of a planar precursor, wherein the planar precursor is a self supporting laminate of two sheets of an acrylic thermoplastic, or of sheets including an acrylic thermoplastic, spaced by, but attaching to, an interposed thermoset polyester system, and wherein curving has involved heating of the laminate sufficient to allow its curving without any substantial degradation of the lamination or its component layers.

1 . A self supporting curved laminate product resulting from curving of a planar precursor,
 wherein the planar precursor is a self supporting laminate of two sheets of an acrylic thermoplastic, or of sheets including an acrylic thermoplastic, spaced by, but attaching to, an interposed thermoset polyester system,   and wherein curving has involved heating of the laminate sufficient to allow its curving without substantial degradation of the lamination or its component layers.   
     
     
         2 . A product of  claim 1  wherein said heating has been into the range of from 105° C. to 120° C. 
     
     
         3 . A product of  claim 1  wherein one or both sheets is of an acrylic plastic or is at least primarily acrylic plastic. 
     
     
         4 . A product of  claim 1  wherein said polyester system has been prepared at least in part from (A) carboxylic acid(s) or dicarboxylic acid(s) with (B) a component or components providing (a) hydroxyl(s) and/or dihydroxyl(s). 
     
     
         5 . A product of  claim 4  wherein said polyester system involves a co-reactive monomer. 
     
     
         6 . A product of  claim 5  wherein co-reactive monomer is styrene or a styrene derivative or analogue. 
     
     
         7 . A product of  claim 6 , wherein the co-reactive monomer is styrene or a styrene analogue that is present in the polyester system in a quantity from 30-55% w/w. 
     
     
         8 . A product of  claim 7  wherein styrene is present in a quantity or/from 35-45% w/w. 
     
     
         9 . A product of  claim 1  wherein the polyester system when cured has an elongation at break greater than 150%. 
     
     
         10 . A product of  claim 9  wherein said elongation at break is greater than 170%). 
     
     
         11 . A product of  claim 1  wherein the polyester system is of a polyester resin containing ethylenic unsaturation is present in the range of from 45-70% w/w. 
     
     
         12 . A product of  claim 1  wherein the polyester system is or has been catalysed by free radical initiators. 
     
     
         13 . A product of  claim 12  wherein a peroxide free initiator is used. 
     
     
         14 . A product of  claim 13  wherein the initiator is MEKP (Methyl Ethyl Ketone Peroxide). 
     
     
         15 . A product of  claim 13  wherein a metal salt promoter is present. 
     
     
         16 . A product of  claim 12  wherein the level of any such initiator is no more than about 2% w/w of the polyester system prior to the thermoset. 
     
     
         17 . A product of  claim 16  wherein the level of such an initiator is less than 1% w/w of the thermoset system. 
     
     
         18 . A product of  claim 1  wherein the lamination of the precursor laminate has involved the laying between flat sheets, or the laying on one flat sheet and subsequent placement of the second flat sheet, of a liquid polyester system and thereafter allowing its thermoset. 
     
     
         19 . A product of  claim 18  wherein the polyester resin system was a mix of:
 45-70% w/w unsaturated polyester resin containing ethylenic unsaturation,   30-55% w/w styrene,   less than 2% w/w catalyst, and   less than 2% w/w initator.   
     
     
         20 . A product of  claim 1  wherein the polyester resin system was mixed in the temperature range 18 to 22° C. 
     
     
         21 . A product of  claim 1  wherein the polyester resin system set at temperature(s) in the range 20° C. to 24° C. 
     
     
         22 . A product of  claim 1  wherein the polyester resin system was mixed at a humidity in the range 57% to 67%. 
     
     
         23 . A product  claim 1  wherein the resin system is allowed to thermoset at a humidity in the range of from 57% to 75%. 
     
     
         24 . A product of  claim 1  wherein that surface of the acrylic plastic which is to interface with the polyester system is a clean face substantially free of release agents and/or migrating materials from any removed cover sheet. 
     
     
         25 . A product of  claim 24  wherein the surface of the sheet(s) has been subjected to cleaning with a solvent. 
     
     
         26 . A product of  claim 25  wherein said sheet(s) has had the surface thereof to be presented to the polyester system, prior to its thermoset, cleaned with isopropyl alcohol. 
     
     
         27 . A product of  claim 1 , wherein said curving is without any substantial detachment of the polyester system attachment to each said sheet. 
     
     
         28 . A product of  claim 1  wherein throughout the curving process the interposed polyester system has remained non liquid. 
     
     
         29 . A product of  claim 1 , wherein the product is transparent. 
     
     
         30 . A product of  claim 1  wherein the polyester system layer is at least 0.5 mm thick and accounts for from 5% to 40% of overall laminate thickness. 
     
     
         31 . A product of  claim 30  which is at least 1 mm thick. 
     
     
         32 . A self supporting transparent laminate able to be curved when all layers of the laminate are heated to a temperature or temperatures unable to melt any layer to a liquid form, the laminate being of a transparent polyester system interposed and attaching to flanking transparent thermoplastic layers, which thermoplastic layers attach to the polyester system by both
 cross linking with free unsaturation in acrylic material,   free monomer solvation of acrylic material,   and wherein each thermoplastic layer comprises an acrylic or PETG.   
     
     
         33 . A self supporting transparent laminate able to be curved when all layers of the laminate are heated to a temperature or temperatures unable to melt any layer to a liquid form, the laminate being of a transparent polyester system interposed and attaching to flanking transparent acrylic thermoplastic layers. 
     
     
         34 . The self supporting transparent laminate of  claim 33 , wherein the laminate is greater than 3 mm thick. 
     
     
         35 . The self supporting transparent laminate of  claim 34 , wherein the polyester system is at least 0.5 mm thick and each thermoplastic layer comprises an acrylic or PETG. 
     
     
         36 . The laminate of  claim 35  wherein the polyester system can account for from 5% to 40% of overall laminate thickness. 
     
     
         37 . A laminate of  claim 33  wherein the polyester system layer is at least 1 mm thick. 
     
     
         38 . The laminate of  claim 33 , the laminate having a performance related to a notional symmetric variant having acrylic layers 2 mm thick on the outside with a core of a polyester system 2 mm thick, the notional variant being able without fracture and/or delamination to withstand a challenge loading in excess of 40 tonnes into its edges, on its minor axis if notionally a rectangle of 960×470 mms. 
     
     
         39 . A laminate of  claim 38  wherein the polyester resin system was in the form of:
 45-70% w/w unsaturated polyester resin containing ethylenic unsaturation,   30-55% w/w styrene,   less than 2% w/w catalyst, and   less than 2% w/w initator, and   when of a thickness of 2 mm, 2 mm and 2 mm through a three layer laminate and when a rectangular panel of 960×470 mm squeezed on its minor axis, it can withstand without delamination between 60 and 80 tonnes.   
     
     
         40 . A method of producing a curved laminate material comprising the steps of:
 providing a laminate of substantially flat sheets of an acrylic and/or PETG thermoplastic having a thermoset polyester resin therebetween, wherein the thermoset resin has an elongation at break of >150% and a glass transition temperature less than ambient temperature,   heating a shaping region of the laminate to a shaping temperature,   shaping the laminate to the desired curvature,   cooling the laminate,   wherein the step of heating the shaping zone of the laminate comprises heating substantially through all layers of the laminate in the shaping zone.   
     
     
         41 . A method of  claim 39  wherein the step of heating the shaping region comprises applying heat to the shaping region from both surfaces of the laminate in the shaping region.