Laminates, panels and means for joining them

A freight container body comprising at least one panel which is a structural laminate comprising two metal sheets and a thermoset reinforced resin core between and bonded to the two metal sheets, wherein each metal sheet has a thickness between 0.015 inch and about 0.1 inch, the thickness of the laminate is less than about 2 inches, and the panel is characterized by having a flexural modulus of at least about 2.5 million psi, by having a core thickness at least equal to the combined thickness of the metal sheets, and by having a weight of no more than about 3 lb/ft.sup.2.

A freight container body comprising at least one panel which is a structural laminate comprising two metal sheets and a thermoset reinforced resin core between and bonded to the two metal sheets, wherein each metal sheet has a thickness between 0.015 inch and about 0.1 inch, the thickness of the laminate is less than about 2 inches, and the panel is characterized by having sufficient impact resistance to pass the falling ball impact test with no delamination of the core and metal sheet or cracking of the core, and characterized by having a shear modulus of at least about 25 ksi.

A laminate comprising two metal sheets and a reinforced thermoset resin core between and bonded to the metal sheets, wherein each metal sheet has a thickness between about 0.015 inch and about 0.1 inch, the thickness of the laminate is less than about 2 inches, and the thickness of the core is at least equal to the combined thickness of the metal sheets, and wherein the laminate is characterized by having a flexural modulus of at least about 2.5 million psi and by having sufficient impact resistance to pass the falling ball impact test with no delamination of the core and metal sheet and no cracking of the core.

A laminate comprising two metal sheets and a reinforced thermoset resin core between and bonded to the two metal sheets, wherein each metal sheet has a thickness between 0.015 inch and 0.1 inch, the thickness of the laminate is less than about 2 inches, and the thickness of the core is at least equal to the combined thickness of the metal sheets, and the laminate is characterized by having a rigidity index of at least about 3,000.

A laminate which comprises two metal sheets and a thermoset resin core between and bonded to the two metal sheets, wherein the metal sheet has a thickness between about 0.040 inch and about 0.070 inch, and wherein the resin core comprises a reinforced thermoset resin and contains a sufficient amount of microballoons to provide a specific gravity of the reinforced resin core is less than about 1.3.

A laminate comprising two metal sheets and a reinforced thermoset resin core between and bonded to the two metal sheets, wherein each metal sheet has a thickness between 0.015 inch and about 0.1 inch, the thickness of the laminate is less than about 2 inches, and the thickness of the core is at least equal to the combined thickness of the metal sheets, and the laminate is characterized by having a shear modulus of the core of at least about 25 ksi wherein the laminate is characterized by having sufficient impact resistance to pass the falling ball impact test with no delamination of the core and metal sheet or cracking of the core.

An assembly comprising substantially abutting sandwich panels each having recessed cores along the length of each adjacent edge;

• an internal splice section, positioned in the two recessed area between the metal sheets of the abutting panels, and extending substantially from the recessed core in the first panel to the recessed core in the second panel;
• and
• means for attaching the splice section to a metal sheet of at least two abutting panels and to at least one other splice section overlapping therewith.

A laminate comprising two aluminum sheets and a plywood core between and bonded to the aluminum sheets with a thermoset resin wherein the aluminum surface of each sheet is anodized with phosphoric acid or etched with chromic acid or dichromate-sulfuric acid before being bonded to the plywood core.

A method of making a laminate comprising placing between two metal sheets having prepared surfaces, a resin composition comprising (a) thermoset resin capable of bonding in neat form to the prepared surfaces of the metal sheets upon curing in neat form to provide a lap shear strength of at least 700 psi, (b) reinforcing material present in an amount between about 3 and about 30 parts by weight based upon the weight of the resin, and (c) microballoons in suspension in the resin present in an amount sufficient to produce the cured reinforced resin composition having a specific gravity less than about 1.3, and curing the resin composition while positioned between and in contact with the two metal sheets.