Inventors:
Steven P. Bitler - Menlo Park CA
David D. Taft - Atherton CA
Ray F. Stewart - Redwood City CA
Assignee:
Landec Corporation - Menlo Park CA
International Classification:
C08L 5100
US Classification:
525107, 525 64, 525 65, 525 66, 525 68, 525 69, 525 74, 525 77, 525 92 R, 525 92 C, 525 92 F, 525 92 H, 525 92 K, 525117, 525118, 525119, 525120, 525121, 525122, 525123, 525132, 525142, 525143, 525144, 525145, 525149, 525168, 525169, 525170, 525182, 525183, 525184, 525199, 525200, 525208, 525218, 525221, 525227, 525240, 525241, 525263, 525293, 525305, 525403, 525404, 525405, 525407, 525408, 525409, 525410, 525411, 525412, 525414, 525420, 525423, 525424, 525425, 525426, 525429, 525438, 525440, 525442, 525444, 525445, 525446, 525 4
Abstract:
The rheological properties of a crosslinkable resin system are modified by the presence of a side chain crystalline (SCC) polymer (or a similar crystalline polymer which melts over a narrow temperature range). The polymer dissolves in the curable system at temperatures above the melting point of the crystalline polymer (T ), but when the system is then cooled to a temperature below T , at least partially forms a separate phase in the curable system. Below T , this separate phase substantially increases the viscosity of the curable system (i. e. makes it thicker than the same system without the crystalline polymer). This is particularly valuable for sheet molding composites (SMCs) in which the increase in viscosity makes the composites less tacky, and for dry film resists (DFRs). Above T , the curable system containing the dissolved crystalline polymer has a viscosity which is substantially less than its viscosity below T.
