Minnesota Mining and Manufacturing Company

Raymond E Grunzinger

Bruce Brandon Wilson

Thomas R Borden

Louis C Belisle

A curable polymer composition for use in providing a dimensionally stable coating comprises a semi-interpenetrating polymer network. The semi-interpenetrating polymer network includes a reactive polymer component, cross-linking agent, and non-reactive polymer component. The non-reactive polymer component has a molecular weight of about 7,000-30,000, and preferably about 15,000. In preferred embodiments, the reactive polymer has a molecular weight of about 30,000-200,000, and preferably about 40,000-60,000. Spacecoat compositions made with formulations described, exhibit good long-term stability, and resistance to failure upon embossing of a substrate to which the retroreflective sheeting is applied.

Embossable sign construction

Polymer composition for use as flexible dimensionally stable coating;

Embedded lens retroreflective sheeting with flexible, dimensionally

A retroreflective sheeting utilizing a particular polymer as the bead bond layer is disclosed. The polymeric bead bond comprises urethane and urea linkages, and has a stage prior to thermosetting in which it may be softened by the application of heat and in which it has a relatively nontacky character. The retroreflective sheeting disclosed possesses the unique combination of high reflectance and superior exterior durability.

Retroreflective sheeting

A method of preparing a storage-stable one-part reactive liquid thermal curing polymeric coating composition from an isocyanate-functional polymeric compound which has a substantial portion of its isocyanate groups masked with an isocyanate masking agent, and a crosslinking agent which is substantially insoluble in aprotic solvents. These liquid compositions are homogeneous even when free of solvents. Preferably the crosslinking agent is a crystalline polyol. The method involves the synthesis of a solubilizing oligomer which is formed by the partial reaction of the crosslinking agent and the unmasked isocyanate-functional polymeric compound. The thermal curing of these compositions results in polymeric coatings which possess superior physical properties. These cured coatings are particularly useful in the manufacture of retroreflective sheeting.

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New Scandia, MN, United States of America

Raymond E Grunzinger