Prilled compounded thermoplastic roadway marking materials
This invention provides a convenient method of forming and applying a thermoplastic material for roadway markings, comprising: obtaining individual components of a thermoplastic composite material suitable for roadway markings; mixing and heating the individual components to produce a fully compounded form of the thermoplastic composite material; solidifying and prilling the fully compounded form of the thermoplastic composite material to produce a plurality of thermoplastic prills; on a marking vehicle or mobile apparatus, introducing the thermoplastic prills to an on-board melter to produce a liquid phase of the thermoplastic prills; and applying the liquid phase of the thermoplastic prills to a roadway, thereby marking the roadway. Compositions and systems are also described. Surprisingly, prills melt in approximately half the time as the powder/granular form. Also, the melter can be operated at lower temperature, leading to less discoloration of material.
1. A method of forming a thermoplastic material for roadway markings, the method comprising:
(a) obtaining individual components of a thermoplastic composite material suitable for roadway markings;
(b) mixing and heating the individual components to produce a fully compounded form of the thermoplastic composite material; and
(c) solidifying and prilling the fully compounded form of the thermoplastic composite material to produce a plurality of thermoplastic prills,
wherein the individual components of the thermoplastic composite material consists of calcium carbonate, reflective glass beads, maleic-modified glycerol rosin ester, rosin ester, paraffinic wax, and titanium dioxide,
wherein the prills have an average maximum length of at least about 1 millimeter.
2. A method of forming a thermoplastic material for roadway markings, the method comprising:
(a) compounding a formulation comprising calcium carbonate, reflective glass beads, at least one rosin ester, a paraffinic wax, and titanium dioxide to form a thermoplastic composite material;
(b) extruding the thermoplastic composite material; and
(c) prilling the thermoplastic composite material to produce a plurality of thermoplastic prills,
wherein the thermoplastic prills have an average maximum length ranging from about 1 millimeter to about 20 millimeters, and wherein the formulation is free of plasticizer.
3. The method of claim 2 , wherein the formulation comprises
about 30-50 wt % calcium carbonate;
about 30-50 wt % reflective glass beads;
about 10-25 wt % maleic-modified glycerol rosin ester;
about 1-9 wt % rosin ester; and
about 1-5 wt % paraffinic wax.
4. The method of claim 2 , wherein an average maximum length of the thermoplastic prills ranges from about 1 millimeter to about 6 millimeters.
5. The method of claim 2 , wherein an average maximum length of the thermoplastic prills ranges from about 1 millimeter to about 10 millimeters.
6. The method of claim 2 , wherein the thermoplastic prills are in a form selected from the group consisting of pellets, spheres, cylinders, rods, squares, tablets, and coins.
7. The method of claim 2 , wherein the thermoplastic prills are in a random form having an average effective diameter of at least about 1 millimeter.
8. The method of claim 2 , wherein a melting temperature of the thermoplastic prills is about 200° C. or less.
9. A system for mixing a thermoplastic material for roadway markings, the system comprising:
(a) a compounding unit comprising more than one zone configured to mix and heat individual components of a thermoplastic composite material suitable for roadway markings to produce a compounded thermoplastic composite material,
wherein the individual components of the thermoplastic composite material comprise at least one rosin ester and a paraffinic wax and are free of plasticizer; and
(b) a prilling unit configured to solidify and prill the compounded thermoplastic composite material.
10. The system of claim 9 , wherein the compounding unit is an extruder.
11. The system of claim 9 , wherein the prilling unit comprises an underwater pelletizer.
12. The system of claim 9 , wherein the prilling unit is further configured to produce prills in a form selected from the group consisting of pellets, spheres, cylinders, rods, squares, tablets, and coins.
13. The system of claim 9 , wherein the prills are in a random form having an average effective diameter of at least about 1 millimeter.
14. The system of claim 9 , wherein the prilling unit is further configured to produce prills with an average maximum length ranging from about 1 millimeter to about 20 millimeters.
15. A method of forming a thermoplastic material for roadway markings, the method comprising:
(a) obtaining individual components of a thermoplastic composite material suitable for roadway markings;
(b) mixing and heating the individual components to produce a fully compounded form of the thermoplastic composite material; and
(c) solidifying and prilling the fully compounded form of the thermoplastic composite material to produce a plurality of thermoplastic prills,
wherein the individual components of the thermoplastic composite material comprises calcium carbonate, reflective glass beads, maleic-modified glycerol rosin ester, rosin ester, paraffinic wax, and titanium dioxide;
wherein the thermoplastic composite material is free of plasticizer; and
wherein the prills have an average maximum length of at least about 1 millimeter.
16. The method of claim 15 , wherein the thermoplastic composite material comprises:
about 30-50 wt % calcium carbonate;
about 30-50 wt % reflective glass beads;
about 10-25 wt % maleic-modified glycerol rosin ester;
about 1-9 wt % rosin ester;
about 1-5 wt % paraffinic wax; and
about 1-3 wt % titanium dioxide.
17. The method of claim 15 , wherein the thermoplastic prills are substantially free of dust.
18. The method of claim 15 , wherein the thermoplastic prills are in a form selected from the group consisting of pellets, spheres, cylinders, rods, squares, tablets, and coins.
19. The method of claim 15 , wherein the thermoplastic prills are in a random form having an average effective diameter of at least about 1 millimeter.
20. The method of claim 15 , wherein an average maximum length of the thermoplastic prills ranges from at least 1 millimeter to about 20 millimeters.