Fully-adhered roof system adhered and seamed with a common adhesive

1. A method of preparing a flat or low-sloped roof, the method comprising:

(i) providing a roof deck with a layer of construction board disposed thereon, where the layer of construction boards includes cellulosic or glass facer;

(ii) providing first and second membrane composites, where each membrane composite includes a polymeric sheet having a roof-facing surface and an upward-facing surface and first and second lateral edges; said roof-facing surface having disposed thereon a layer of pressure-sensitive adhesive, where the layer of pressure-sensitive is disposed on the entirety of the roof-facing surface from the first lateral edge to the second lateral edge, the pressure-sensitive adhesive layer including a UV-cured polyacrylate having a gel content, as determined by THF extraction after boiling in THF after four hours, of at least 50% by weight, and where the polyacrylate, prior to UV curing, has a Tg of less than −20° C. and a number average molecular weight of from about 100 to about 350 kg/mol, and where the membrane composite further includes a release member disposed on the layer of pressure-sensitive adhesive;

(iii) removing the release member from the first membrane composite;

(iv) securing the first membrane composite to the layer of construction boards by mating the pressure-sensitive adhesive to the layer of construction boards;

(v) positioning the second membrane composite adjacent to the first membrane composite in a manner that the second membrane composite partially overlaps the first membrane composite to thereby form a lap portion;

(vi) removing the release member from the second membrane composite;

(vii) securing the second membrane composite to the layer of construction boards by mating the pressure-sensitive adhesive on the second membrane composite to the layer of construction boards;

(viii) applying a primer to the upward-facing surface of the first composite in the lap portion to thereby form a primed portion on the first membrane composite;

(ix) forming a seam between the first membrane composite and the second membrane composite by mating the pressure-sensitive adhesive of the second membrane composite to the primed portion of the first membrane composite, said seam including a seam edge formed by a lateral edge of the second membrane composite; and

(x) applying a sealant along the seam edge.

2. The method of claim 1 , where the pressure-sensitive adhesive layer including a UV-cured polyacrylate having a gel content, as determined by THF extraction after boiling in THF after four hours, of at least 60% by weight.

3. The method of claim 1 , where the pressure-sensitive adhesive layer including a UV-cured polyacrylate having a gel content, as determined by THF extraction after boiling in THF after four hours, of from about 50% to about 90%.

4. The method of claim 1 , where the pressure-sensitive adhesive layer including a UV-cured polyacrylate having a gel content, as determined by THF extraction after boiling in THF after four hours, of from about 60% to about 80%.

5. The method of claim 1 , where the pressure-sensitive adhesive layer is characterized by a peel strength when adhered to the adjacent membrane, as determined by ASTM D-1876-08, of at least 3.6 lbf/in.

6. The method of claim 1 , where the pressure-sensitive adhesive layer is characterized by a peel strength when adhered to the adjacent membrane, as determined by ASTM D-1876-08, of at least 8.0 lbf/in.

7. The method of claim 1 , where the pressure-sensitive adhesive layer is characterized by a peel strength when adhered to the adjacent membrane, as determined by ASTM D-1876-08, of at least 15 lbf/in.

8. The method of claim 1 , where the polymeric sheet is a thermoplastic membrane panel.

9. The method of claim 1 , where the polymeric sheet is an EPDM membrane panel.

10. A method of installing a roof system, the method comprising:

(i) providing a first polymer membrane sheet secured to a roof surface, the first polymer membrane sheet including a upward-facing surface and a first lateral edge, the first polymer membrane sheet further including a layer of primer disposed on a portion of said upward-facing surface along said first lateral edge;

(ii) providing a membrane composite including a polymer membrane having an upward-facing surface and downward-facing surface, first and second lateral edges, a pressure-sensitive adhesive layer disposed on the downward-facing surface and extending from the first lateral edge to the second lateral edge, and a release member removably affixed to the pressure-sensitive adhesive layer, where said pressure-sensitive adhesive is a UV-cured polyacrylate having a gel content, as determined by THF extraction after boiling in THF after four hours, of from about 50% to about 90%, and where said UV-cured polyacrylate, prior to being cured, includes one or more units defined by the formula:

where each R 1 is individually hydrogen or a hydrocarbyl group and each R 2 is individually a hydrocarbyl group;

(iii) positioning the membrane composite adjacent to the first polymer membrane sheet secured to a roof surface, where said step of positioning places the membrane composite in an manner that overlaps the primer layer disposed on the first polymer membrane;

(iv) adhesively securing the membrane composite to the roof surface by mating a portion of the pressure-sensitive adhesive layer to the roof surface;

(v) adhesively securing the membrane composite to the first polymer membrane by mating a portion of the pressure-sensitive adhesive layer to the primed surface.

11. The method of claim 10 , where each R 1 and R 2 , respectively, throughout the polymer are the same in each unit.

12. The method of claim 10 , where each R 2 is an alkyl group having at least 4 carbon atoms.

13. The method of claim 12 , where each R 1 is hydrogen and each R 2 , throughout the polymer, is an alkyl group having at least 4 carbon atoms.

14. A membrane composite comprising:

(i) a membrane panel having opposed first and second planar surfaces, said first planar surface including a roof-substrate contacting portion and a lap portion;

(ii) a pressure-sensitive adhesive layer disposed on said roof-substrate contacting portion and said lap portion, said pressure-sensitive adhesive layer including a UV-cured polyacrylate having a gel content, as determined by THF extraction after boiling in THF after four hours, of at least 50% by weight, and where the polyacrylate, prior to UV curing, has a Tg of less than −20° C. and a number average molecular weight of from about 100 to about 350 kg/mol; and

(iii) a release member removably affixed to said pressure-sensitive adhesive layer in both said roof-substrate contacting portion and said lap portion, where said pressure-sensitive adhesive layer disposed on said roof-substrate portion and said lap portion is substantially homogeneous.

15. The membrane of claim 14 , where said release member includes a perforation that allows said release member to be divided between said roof-substrate contacting portion and said lap portion.

16. The roof system of claim 14 , where the degree of cure of said UV-cured adhesive varies by no more than 10% between said roof-substrate contacting portion and said lap portion.

17. The membrane of claim 14 , where the degree of cure of said UV-cured adhesive varies by no more than 1% between said roof-substrate contacting portion and said lap portion.

18. The membrane of claim 14 , where the UV-cured adhesive is a UV-cured polyacrylate, and where said UV-cured polyacrylate, prior to being cured, includes one or more units defined by the formula:

where each R 1 is individually hydrogen or a hydrocarbyl group and each R 2 is individually a hydrocarbyl group.