Foam gasket and bonding tape based on polyurethane dispersions

A method of preparing a polymer sheet, the method comprising:

• frothing a polyurethane dispersion into a froth;
• casting the froth onto a liner;
• treating the froth to have a uniform thickness;
• drying the froth to form a polyurethane core having a thickness of at least 0.5 of a total thickness of the polymer sheet,
• wherein the polyurethane core comprises polyurethane polymer, wherein the polyurethane core has a loss of tensile strength when exposed to UV light according to standard SAE J1960 (Rev. August 2003) of not greater than about 30%.

An assembly comprising:

• a first member;
• a second member;
• and
• a gasket;
• wherein the gasket includes a polyurethane core,
• wherein the polyurethane core has a first major surface and a second major surface opposite the first major surface,
• wherein the gasket is compressed between the first member and the second member at a compression of at least about 10%,
• wherein the polyurethane core comprises a polyurethane polymer, and
• wherein the polyurethane core has a loss of tensile strength when exposed to UV light according to standard SAE J1960 (Rev. August 2003) of not greater than 30%.