Patent Application
20230303854
The present invention relates to road marking paint compositions in general, and in particular to a hot-melt road marking paint composition.
Road marking paint are typically utilized for marking lanes, pedestrians' crossings, etc. on roads. Essential components of conventional melt-bonding (or hot-melt) road marking paint include a pigment, a silica, a filler, and a binder.
Melt-bonding road marking paint typically comes in a powder form. Before application, the road marking paint powder is initially melted in a hot melt kettle. The molten road marking paint can then be applied (such as spraying) onto a road surface to form the desired shape for road markings. The road marking paint coated on the road surface can be cooled and solidified in a few minutes.
The road marking paint is required to have properties such as fast drying, wear resistance, diffusive reflectivity, and strong peel strength after solidification.
The present disclosure provides an improved composition for melt-bonding road marking paint.
In accordance with one embodiment, a road marking paint composition includes, percentage by weight, 8-15% titanium dioxide, 25-45% glass beads, 20-42% calcium carbonate, 18-23% binder, and 1-5% polyethylene terephthalate.
In accordance with another embodiment, a road marking paint composition includes, percentage by weight, 1-1.5% chrome yellow 83, 30-45% glass beads, 20-42% calcium carbonate, 18-23% binder, and 1-5% polyethylene terephthalate.
All features and advantages of the present invention will become apparent in the following detailed written description.
The invention itself, as well as a preferred mode of use, further objects, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
Essential components of conventional melt-bonding road marking paint include a pigment, a silica in the form of glass beads, a filler and a binder along with a plasticizer. The two most common pigment colors are white and yellow. White pigments are mainly titanium dioxide, zinc oxide, and lithophone. Yellow pigment is lead and chromate free, and is also heat-resistant. Silica glass beads, which are generally colorless and transparent, provide light refraction, focusing and directional reflection. Dispensed throughout a road paint coating surface, glass beads can reflect car light back to drivers' eyes to improve visibility of road markings. The filler ensures mechanical strength, wear resistance, and color of paint coating. The binder allows the road marking paint to be fast-drying and strongly adhesive to a road surface.
In accordance with one embodiment of the present invention, polyethylene terephthalate (PET or PETE) is utilized as an additive for manufacturing melt-bonding road marking paint. PET is a polymer resin of the polyester family. The main source of PET can be recycled plastic water bottles. In addition being an additive, PET also replaces certain amount of silica glass beads and filler needed to be employed in conventional melt-bonding paint compositions. For example, the percentage of PET used in the paint composition may replace the same amount of silica glass beads and/or calcium carbonate filler.
Components of white color melt-bonding road marking paint include a white pigment, a silica, a filler, a binder, and an additive.
The white pigment is a rutile titanium dioxide, which preferably meets the ASTM D 476, Type II or V standard. A maximum of 17% of the total white pigment content may be ASTM D 476 Type I anatase titanium dioxide. When washed free of resins by solvent washing, the white pigment should be able to meet the U.S. Standard Sieve Number 200.
Silica glass beads should have an index of refraction between 1.50 and 1.53 at 25° C. Silica glass beads should meet the requirement of AASHTO M247 Type 1.
The filler is calcium carbonate of 95% purity.
The binder includes a mixture of thermoplastic resins (at least one of which is a solid at room temperature) and one or more plasticizers having a high boiling point. One example of plasticizers is castol oil. At least ⅓ of the binder composition is a maleic-modified glyceryl ester of rosin, and not less than 8% by weight of the entire material composition.
PET is utilized as an additive. PET can be formed by pulverizing clear recycled plastic into micron size beads.
Table I shows the composition of a white color melt-bonding type road marking paint in percentages by weight.
Components of yellow color melt-bonding road marking paint include a yellow pigment, a silica, a filler, a binder, and an additive.
The yellow pigment should be a lead and chromate free, organic yellow pigment that is heat-resistant. One example of yellow pigment is C.I. Pigment Yellow 83, opaque version.
Silica glass beads should have an index of refraction between 1.50 and 1.53 at 25° C. Silica glass beads should meet the requirement of AASHTO M247 Type 1.
The filler is calcium carbonate of 95% purity.
The binder includes a mixture of thermoplastic resins (at least one of which is a solid at room temperature) and one or more plasticizers having a high boiling point. One example of plasticizers is castol oil. At least ⅓ of the binder composition is a maleic-modified glyceryl ester of rosin, and not less than 8% by weight of the entire material composition.
PET is utilized as an additive. PET can be formed by pulverizing clear recycled plastic into micron size beads.
Table II shows the composition of a yellow color melt-bonding type road marking paint in percentages by weight.
Referring now to the drawings and in particular to
As has been described, the present invention provides an improved composition of melt-bonding road marking paints. The usage of PET in the form of recycled plastic can lessen the cost of making melt-bonding road marking paints. In addition, since the source of PET typically comes from recycled plastic bottles, the present invention helps remove excess waste plastics from the environment.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
