Patent ID: 7645416

Claim:
A method for controlling spherulite formation during thermoforming a laminated thermoplastic sheet, wherein the thermoforming comprises the steps of: a) heating the laminated thermoplastic sheet, wherein the laminated thermoplastic sheet has a first side and an opposite second side, wherein the first side comprises a class “A” paint film having an initial gloss; b) placing the heated laminated thermoplastic sheet into a thermoformer, wherein the thermoformer has a mold surface and wherein the second side of the laminated thermoplastic film faces toward the mold surface; c) cooling the mold surface; d) applying vacuum to the thermoformer, wherein the vacuum acts suckingly upon the second side of the laminated thermoplastic sheet; and e) applying chilled compressed air having a temperature less than 70 degrees F to the thermoformer during the step d), wherein the chilled compressed air acts pressurably upon the first side of the laminated thermoplastic sheet; wherein the vacuum and the chilled compressed air act on the laminated thermoplastic sheet to cause the laminated thermoplastic sheet to conform to a shape of the mold surface; and wherein the chilled compressed air causes the laminated thermoplastic sheet to cool at a rate which preserves the initial gloss of the class “A” paint film; said method for controlling spherulite formation comprising at least one step selected from the group of steps consisting of: aa) adding a nucleating agent to the paint film prior to step a); bb) performing step e) using the chilled compressed air at a temperature of substantially between 32 degrees F and 50 degrees F; cc) performing step a) such that the paint film of the laminated thermoplastic sheet is kept below substantially between 311 degrees F and 330 degrees F; and dd) selecting the paint film, prior to step a), such that the paint film has a high melting point temperature relative to a temperature imparted to the paint film in step a).