Roofing underlayment
A breathable synthetic roofing underlayment having a hydrophobic nonwoven layer on top to deflect water, a liquid water-resistant and vapour-permeable membrane layer in the middle, and a bottom nonwoven layer which is hydrophilic and has rapid and high liquid water absorbency. This accelerates the movement of liquid water from a roofing deck into the nonwoven bottom layer and increases the rate of transfer of water through the underlayment. The bottom layer comprises a carrier resin and a hydrophilic agent, which may be a polyamide such as polycaprolactam (Nylon 6) or poly(hexamethylene adipamide), a polysorbate or other composition. The underlayment is especially useful for application to wet roofing decks.
1. A roofing underlayment comprising:
a first layer; and
a non-woven second layer configured to contact a roof deck,
wherein the non-woven second layer comprises:
a carrier resin; and
at least one hydrophilic agent, wherein a total amount of all hydrophilic agents in the non-woven second layer is 1% to 10% by weight based on a total weight of the carrier resin and the at least one hydrophilic agent;
wherein the roofing underlayment has a breathability of at least 10 perms when measured in accordance with standard test method ASTM E96.
2. The roofing underlayment of claim 1 , further comprising:
a third layer,
wherein the third layer is a thermoplastic polyolefin sheet;
wherein the first layer is between the third layer and the non-woven second layer.
3. The roofing underlayment of claim 1 , further comprising:
a non-woven third layer,
wherein the first layer is between the non-woven third layer and the non-woven second layer.
4. The roofing underlayment of claim 1 , wherein the hydrophilic agent comprises a polysorbate.
5. The roofing underlayment of claim 4 , wherein the polysorbate comprises polyoxyethylene (20) sorbitan monooleate (polysorbate 80).
6. The roofing underlayment of claim 4 , wherein the polysorbate comprises polyoxyethylene (20) sorbitan monolaurate (polysorbate 20).
7. The roofing underlayment of claim 1 , wherein the hydrophilic agent comprises a mixture of polyethylene, polypropylene, wax, and polyacrylamide.
8. The roofing underlayment of claim 1 , wherein the hydrophilic agent comprises silica-alumina.
9. The roofing underlayment of claim 1 , wherein the roofing underlayment has a surface wettability on its bottom surface such that a contact angle between the bottom surface and water decreases to 0° in less than 6 seconds, measured in accordance with standard test method ASTM D724.
10. The roofing underlayment of claim 1 , wherein the carrier resin comprises a polyolefin.
11. A roofing system comprising:
a roof deck;
a roofing material; and
a roofing underlayment installed between the roofing material and the roof deck,
wherein the roofing underlayment comprises:
a first layer; and
a non-woven second layer,
wherein the non-woven second layer comprises:
a carrier resin; and
at least one hydrophilic agent, wherein a total amount of all hydrophilic agents in the non-woven second layer is 1% to 10% by weight based on a total weight of the carrier resin and the at least one hydrophilic agent;
wherein the non-woven second layer is located between the first layer and the roof deck;
wherein the non-woven second layer directly contacts the roof deck;
wherein the roofing underlayment has a breathability of at least 10 perms when measured in accordance with standard test method ASTM E96.
12. The roofing system of claim 11 , wherein the roofing underlayment further comprises:
a third layer,
wherein the third layer is a thermoplastic polyolefin sheet;
wherein the first layer is between the third layer and the non-woven second layer.
13. The roofing system of claim 11 , wherein the roofing underlayment further comprises:
a non-woven third layer,
wherein the first layer is between the non-woven third layer and the non-woven second layer.
14. The roofing system of claim 11 , wherein the hydrophilic agent comprises a polysorbate.
15. The roofing system of claim 14 , wherein the polysorbate comprises polyoxyethylene (20) sorbitan monooleate (polysorbate 80).
16. The roofing system of claim 14 , wherein the polysorbate comprises polyoxyethylene (20) sorbitan monolaurate (polysorbate 20).
17. The roofing system of claim 11 , wherein the hydrophilic agent comprises a mixture of polyethylene, polypropylene, wax, and polyacrylamide.
18. The roofing system of claim 11 , wherein the hydrophilic agent comprises silica-alumina.
19. The roofing system of claim 11 , wherein the roofing underlayment has a surface wettability on its bottom surface such that a contact angle between the bottom surface and water decreases to 0° in less than 6 seconds, measured in accordance with standard test method ASTM D724.
20. The roofing system of claim 11 , wherein the carrier resin comprises a polyolefin.