System, method, and composition for adhering preformed thermoplastic traffic control signage to pavement
View Patent ↗The present invention relates to a method for adhering detectable warning devices, pavement markings and preformed traffic control devices (turn arrows, stop bars) that are hydrocarbon or alkyd thermoplastic in nature to an uncured or “green” concrete substrate providing permanent adhesion for detectable warning devices, pedestrian and traffic control markings.
1. A method of bonding a preformed thermoplastic road marker with top surface signage to uncured concrete exhibiting laitance comprising;
a) providing a first underlying substrate consisting of uncured concrete and applying an epoxy polymer that has a viscosity in the range of 100 to 300 centipoises upon the uncured concrete such that the epoxy seeps into the uncured concrete;
b) mating a preformed thermoplastic road maker with a second overlying layer with top surface signage upon said epoxy coated surface of the uncured concrete to form a laminate, wherein said epoxy polymer is a mixture consisting of an isocyanate-functional prepolymer, a silane and an amount of terpene-phenolic resin effective to provide curing;
c) heating said laminate in the presence of moisture to form a concrete bonded preformed thermoplastic road marker with top surface signage whereby the final bond strength exceeds 180 psi between all layers.
2. The preformed thermoplastic road marker method according to claim 1 , wherein said uncured concrete has been previously shaped and formed within about 24 hours to about 2 weeks.
3. The method according to claim 1 , wherein said first underlying substrate requires no laitance removal.
4. The method according to claim 1 , wherein said curable epoxy within said first underlying substrate remains uncured for at least 1 minute.
5. The method according to claim 1 , wherein said thermoplastic signage meets AASHTO (American Association of State Highway road marker Transportation Officials) Designation M 249-98 specifications.
6. The method according to claim 1 , wherein the means of said heating comprises an open flame, closed flame, and/or an electronic resistive source in a torch or heated roller form.
7. The method according to claim 1 , wherein said heating occurs more than one time when application of said thermoplastic signage of said overlying to said underlying substrate occurs.
8. The method according to claim 1 , wherein said heating elevates the temperature of said thermoplastic signage to about 400 degrees F. to about 450 degrees F.
9. The method according to claim 8 , wherein said thermoplastic signage softening point is from about 400 degrees F. to about 450 degrees F. as determined by ring and ball testing methods.
10. The method according to claim 1 , wherein said heating of said thermoplastic signage together with said thermoplastic road marker causes said thermoplastic signage to flow into said first underlying substrate to a depth from about 0.001 mm to about 10 mm.
11. The method according to claim 1 , wherein said bond strength is from about 200 psi to about 500 psi.