Peel and stick roofing membranes with cured pressure-sensitive adhesives
A membrane composite comprising a polymeric membrane panel, an adhesive layer, and a release member, where the adhesive layer is a pressure-sensitive adhesive that is at least partially cured, and where the adhesive layer has a thickness of at least 102 μm.
1. A process for forming a roofing membrane composite, the process comprising:
heating a melt-extrudable, UV-curable pressure-sensitive adhesive composition to allow the adhesive to flow, where the adhesive composition comprises a polyacrylate elastomer and, optionally, one or more of photoinitiators, solvents, plasticizers, and resins;
applying the adhesive composition to a planar surface of a roofing membrane panel, where the membrane panel is adapted to provide a weatherproof polymeric barrier to a building structure, to thereby form an adhesive layer having a thickness of at least 152 μm;
subjecting the adhesive layer to UV radiation to thereby effect crosslinking of the polyacrylate elastomer to form a cured adhesive layer comprising a cross-linked infinite polymer network;
applying a release member to the cured adhesive layer to form a roofing member composite; and
winding the composite.
2. The process of claim 1 , where said step of heating heats the adhesive composition to a temperature of from about 120 to about 160° C.
3. The process of claim 1 , where said step of subjecting the coating to UV radiation includes subjecting the adhesive layer to a UV dosage of from about 50 to about 230 millijoules/cm2.
4. The process of claim 1 , where said step of subjecting the coating to UV radiation includes subjecting the adhesive layer to at least 150 milliWatts/cm2 of UV energy.
5. The process of claim 1 , where said step of subjecting the coating to UV radiation includes subjecting the adhesive layer to at least 200 milliWatts/cm2 of UV energy.
6. The process of claim 1 , where the polyacrylate elastomer includes one or more units deriving from butyl acrylate or 2-ethylhexyl acrylate.
7. The process of claim 1 , where the polyacrylate elastomer has a Tg of less than 0° C.
8. The process of claim 1 , where the polyacrylate elastomer includes polymerized units that serve as photoinitiators.
9. The process of claim 1 , where the polyacrylate elastomer is characterized by a number average molecular weight of from about 100 to about 350 kg/mol.
10. The process of claim 1 , where the polyacrylate elastomer is characterized by a Brookfield viscosity at 150° C. of from about 20,000 to about 70,000 cps.
11. The process of claim 1 , where the roofing membrane panel is a thermoplastic or cured rubber membrane.
12. The process of claim 1 , where the roofing membrane panel is EPDM.
13. The process of claim 1 , where the roofing membrane panel has a width of from about 1 to about 20 meters.
14. The process of claim 1 , where the roofing membrane panel has a thickness of from about 500 μm to about 3 mm.
15. The process of claim 1 , where the cured adhesive layer is in contact with substantially all of one planar surface of the membrane panel.
16. The process of claim 1 , where the membrane composite is characterized by a peel strength, when adhered to a stainless steel panel and tested according to PSTC 101 , of at least 3.0 psi.
17. The process of claim 1 , where the membrane composite is characterized by a dead load shear, when adhered to a stainless steel panel and tested according to PSTC 107 , of at least 0.5 hour.