Bitumen vulcanizing composition
View Patent ↗Provided is a vulcanizing agent for vulcanizing bitumen, which vulcanizing agent comprises a sulphur agent and a binder, wherein the vulcanizing agent is in the form of pellets. Further provided is a process for producing a surfacing composition, which process comprises contacting bitumen with an elastomer and the vulcanizing agent of the present invention.
1. A process for producing a surfacing composition comprising contacting bitumen with an elastomer and a pelletized vulcanizing agent comprising pellets incorporating a particulate sulfur agent and a binder for said sulfur agent which holds the particles of the sulfur agent together to form pellets which are larger than the sulfur agent particles without the incorporation of a binder.
2. A process according to claim 1 wherein said bitumen is contacted with said elastomer and said vulcanizing agent at a temperature of at least 100° C.
3. The process of claim 2 wherein said bitumen and elastomer and vulcanizing agent are contacted at a temperature within the range of 120-200° C.
4. The process of claim 2 , wherein said elastomer and said bitumen are contacted in relative amounts of 1-15 parts by weight of said elastomer and 85-99 parts by weight by said bitumen.
5. The process of claim 4 wherein said elastomer and said bitumen are contacted in relative amounts of 1-10 parts by weight of said elastomer and 90-99 parts by weight of said bitumen.
6. The process of claim 4 wherein said vulcanizing agent is added in an amount within the range of 0.01-10 wt. % of the total weight of said bitumen and said elastomer.
7. The process of claim 6 wherein said vulcanizing agent is added in an amount within the range of 0.1-5 wt. % of the total weight of said bitumen and said elastomer.
8. The process of claim 1 wherein the elastomer is selected from the group consisting of styrene butadiene styrene, hydrogenated styrene butadiene styrene, styrene isoprene styrene, styrene ethylene butadiene styrene, polyisobutadiene and mixtures thereof.
9. The process of claim 1 wherein said surfacing composition is incorporated into a road pavement.
10. The process of claim 1 wherein said elastomer and said pelletized vulcanizing agent are added together to said bitumen.
11. The process of claim 1 wherein said pellets incorporate said particulate sulfur agent in an amount within the range of 10-80 wt. % and said binder in an amount within the range of 20-90 wt. %.
12. The process of claim 11 wherein said sulfur agent comprises elemental sulfur in an amount within the range of 10-100 wt. %.
13. The process of claim 12 wherein said sulfur agent comprises a sulfur-containing compound in an amount of up to 90 wt. % of said pelletized vulcanizing agent.
14. The process of claim 13 wherein said sulfur-containing compound in said pelletized vulcanizing agent comprises a sulfur donor.
15. The process of claim 14 wherein said sulfur-containing compound in said pelletized vulcanizing agent is selected from the group consisting of zinc dibutyldithiocarbamate and zinc mercaptobenzothiazol.
16. The process of claim 14 wherein the binder in said pelletized vulcanizing agent is selected from the group consisting of a wax, a hydrocarbon resin, a co-polymer of ethylene and an acrylic acid, polyethylene, glycol monostearate, and ethyl vinyl alcohol, and mixtures thereof.