초록 ▼

Structurally strong articles are formed from inherently weak materials, such as expanded polystyrene, coated with one or more layers of a thermoplastic sheet material, such as amorphous polyethylene terephthalate. The inherently weak interior members are either fluid permeable or perforated. These m

Structurally strong articles are formed from inherently weak materials, such as expanded polystyrene, coated with one or more layers of a thermoplastic sheet material, such as amorphous polyethylene terephthalate. The inherently weak interior members are either fluid permeable or perforated. These members are sandwiched or encapsulated by heat deformable outer layers. The articles are made by applying a fluid pressure between the stack of interior members and the thermoplastic sheet, with the thermoplastic sheet heated to conform to the interior members. The fluid pressure is maintained until the thermoplastic sheet is cooled so that tension extending in all directions is produced in the sheet. The resulting articles are useful as building elements, signs, motor vehicle panels, pallets, surf boards, and sail boards.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of forming a layered structural article having load bearing capabilities from a plurality of shape defining interior members and at least one external skin, each of said plurality of shape defining interior members not being inherently load bearing and being at

[ What is claimed is:] [1.]1. A method of forming a layered structural article having load bearing capabilities from a plurality of shape defining interior members and at least one external skin, each of said plurality of shape defining interior members not being inherently load bearing and being at least partially fluid permeable, said method comprising:(1) laminating a plurality of shape defining interior members to form a stack;(2) heating a thermoplastic sheet for forming an external skin of the layered structural article;(3) moving said thermoplastic sheet, while heated, relative to said stack, to bring said sheet, while heated, into a position overlying said stack;(4) applying a fluid pressure differential between a side of said sheet remote from said stack and a side of said stack remote from said sheet, to compress said plurality of members of said stack and conform said sheet to said stack and mutually engage said sheet and said stack compressed by the fluid pressure differential, air initially trapped between said stack and said sheet and within said stack passing through said stack; and(5) maintaining the fluid pressure differential on said stack until said thermoplastic sheet has cooled so that tensional forces arise in said sheet and extend in all directions.