Pressure-sensitive adhesives including expandable graphite
View Patent ↗A building material comprising a substrate layer and a pressure-sensitive adhesive layer, where the pressure-sensitive adhesive layer includes expandable graphite.
1. A method of preparing a composite, the method comprising the steps of:
i. providing a polymeric sheet;
ii. applying a pressure-sensitive adhesive having a first and second planar surfaces to the polymeric sheet; and
iii. applying expandable graphite to the second planar surface of the pressure-sensitive adhesive to form a concentrated region of expandable graphite.
2. The method of claim 1 wherein the concentrated region of expandable graphite is discontinuous to thereby allow the pressure-sensitive adhesive to be exposed.
3. The method of claim 1 wherein the first planar surface of the pressure-sensitive adhesive is fixedly attached to the polymeric sheet.
4. The method of claim 1 wherein a release liner is removably attached to the second planar surface of the pressure-sensitive adhesive.
5. The method of claim 4 wherein said concentrated region of expandable graphite is proximate to the release liner relative to the polymeric sheet.
6. The method of claim 1 wherein the first planar surface of the pressure-sensitive adhesive is substantially devoid of expandable graphite.
7. The method of claim 1 wherein the concentrated region of expandable graphite has a thickness of from about 10 μm to about 3 mm.
8. The method of claim 1 wherein the polymeric sheet includes a thermoplastic sheet.
9. The method of claim 1 wherein the polymeric sheet includes a thermoset sheet.
10. The method of claim 1 wherein the concentrated region of expandable graphite is formed to by dropping expandable graphite on to the second planar surface of the pressure-sensitive adhesive.
11. The method of claim 10 wherein the expandable graphite is at least partially embedded within the pressure-sensitive adhesive.
12. The method of claim 11 , where the concentrated region of expandable graphite is partially dispersed within said pressure-sensitive adhesive to form a concentration gradient whereby the concentration of the expandable graphite within the pressure-sensitive adhesive moves from a region of maximum concentration proximate to the second planar surface of the pressure-sensitive adhesive to a region of minimum concentration at the first planar surface of the pressure-sensitive adhesive.