Pavement marking article and raised pavement marker that uses pressure sensitive adhesive
View Patent ↗A pavement marking article that has an adhesive composition for adhering the article to a pavement substrate, where the adhesive composition includes a reaction product of an acrylic acid ester of a monohydric alcohol whose homopolymer has a Tg less than 0° C., a non-polar ethylenically unsaturated monomer, and 0-10 parts by weight of a polar ethylenically unsaturated monomer. Preferably the amount of the acrylic acid ester is about 60-90 parts by weight, and the amount of the non-polar ethylenically unsaturated monomer is about 10-40 parts by weight. Also, a raised pavement marker that comprises: (a) a pavement marker body having upper and lower surfaces and an apparent flexural modulus of at least about 50,000 psi and (b) a pressure sensitive adhesive layer disposed upon the lower surface of the marker, wherein the adhesive has: (i) a transition region that begins at a frequency of about 10,000 radians/s or more and extends to a frequency of about 100 radians/s or less at about 25° C.; and (ii) a minimum shear modulus of about 1×105 Pa at an impact frequency of about 100 radians/s at 25° C.; and (iii) a shear modulus value of about 2×104 to 2×105 Pa at a frequency of 1 rad/sec at 25° C. Raised pavement markers that use a pressure sensitive adhesive meeting parameters (i)-(iii) can demonstrate good adhesion to roadways and are capable of withstanding repeated impacts from motor vehicle tires.
1. A raised pavement marker that comprises:
(a) a pavement marker body having upper and lower surfaces and an apparent flexural modulus of at least about 50,000 psi and
(b) a pressure sensitive adhesive layer disposed upon the lower surface of the marker, wherein the adhesive has:
(i) a transition region that begins at a frequency of about 10,000 radians/s or more and extends to a frequency of about 100 radians/s or less at about 25° C.;
(ii) a minimum shear modulus of about 1×10 5 Pa at an impact frequency of about 100 radians/s at 25° C.; and
(iii) a shear modulus value of about 1×10 4 to 2×10 5 Pa at a frequency of 1 rad/sec at 25° C.; and the adhesive composition comprises about 40 to 60 wt-% polybutadiene and about 40 to 60 wt-% tackifier.
2. The raised pavement marker of claim 1 further comprising a conformance layer.
3. The raised pavement marker of claim 2 wherein the conformance layer has a tensile yield point of about 13 to 30 N.
4. The raised pavement marker of claim 1 wherein the adhesive comprises about 32 wt-% polybutadiene; about 8 wt-% of a styrene/butadiene copolymer about 40 wt-% of an α-pinene tackifier and about 10 wt-% of a hydrocarbon tackifier.
5. The raised pavement marker of claim 1 wherein the marker is a multi-component marker.
6. The raised pavement marker of claim 1 wherein the marker is a one-piece molded marker.
7. The raised pavement marker of claim 1 , wherein the pressure sensitive adhesive has a shear modulus of about 2×10 4 to 1×10 5 Pa at a frequency of 1 rad/sec at 25° C.
8. The raised pavement marker of claim 1 , wherein the pressure sensitive adhesive has a shear modulus of about 2×10 5 Pa or greater at a frequency of 100 rad/sec at 25° C.
9. The raised pavement marker of claim 1 , wherein the pressure sensitive adhesive has a shear modulus of about 5×10 5 Pa or greater at a frequency of 100 rad/sec at 25° C.
10. The raised pavement marker of claim 1 , wherein the pressure sensitive adhesive has a shear modulus of about 2×10 5 to 5×10 7 Pa at a frequency of 100 to 1000 rad/sec at 25° C.
11. A marked road surface, comprising a raised pavement marker of claim 1 adhered to the road surface.