Improved pavement marking method
AssigneeMinnesota Mining and Manufacturing Company
InventorOlexander Hnojewyj
Life of this patent
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Abstract
Pavement markings of improved durability are obtained by first forming a bonding layer on the pavement surface with a liquid coating composition that comprises a polyamide condensation product of dimerized fatty acid and polyamine and then forming a top or marking layer over the bonding layer by applying through a flame solid particles of a marking material that comprises the same type of polyamide, preferably in a higher-molecular-weight version.
Claims9
In a method for making a paved roadway surface without first severely cleaning the surface comprising coating onto the surface a thin bonding layer of low-viscosity liquid coating composition which wets the paved surface and then rapidly advances to a nonspreading form, heating the paved surface and the bonding layer, projecting toward the heated layer a topcoat material that comprises a continuous stream of solid individual particles having an organic thermoplastic phase that comprises a polyamide condensation product of dimerized fatty acid and polyamine, and heating the particles so as to cause at least a major portion of the organic thermoplastic phase of the particles to soften before they reach the bonding layer;
- the improvement which comprises using as the liquid coating composition a material that has a room-temperature viscosity of less than about 1000 centipoises and comprises 100 parts of a thermoplastic polyamide condensation product of a dimerized fatty acid and an amine;
- and at least 50 parts of volatile solvent in which said condensation product is dissolved;
- the bonding layer formed by said liquid coating composition having an evaporation rate of at least 0.02 gram/square centimeter/hour at a temperature of 24.degree. C and a relative humidity of 50%.
In a method for marking a paved roadway surface without first severely cleaning the surface comprising coating onto the surface a thin bonding layer of low-viscosity liquid coating composition which wets the paved surface and then rapidly advances to a nonspreading form, heating the paved surface and the bonding layer, projecting toward the heated bonding layer a topcoat material that comprises a continuous stream of solid individual particles having an organic thermoplastic phase that comprises a polyamide condensation product of dimerized fatty acid and polyamine, and heating the particles so as to cause at least a major portion of the organic thermoplastic phase of the particles to soften before they reach the bonding layer;
- the improvement which comprises (1) using as the liquid coating composition a material that has a room-temperature viscosity of less than about 100 centipoises and comprises 100 parts of a thermoplastic polyamide condensation product of a dimerized fatty acid and an amine having a melt-viscosity of less than 1000 centipoises at 160.degree. C;
- and at least 50 parts of volatile solvent in which said condensation product is dissolved, and which evaporates from said liquid coating composition at a rate of at least 0.04 gram/square centimeter/hour at a temperature of 24.degree. C and a relative humidity of 50%;
- and (2) using a topcoat material that comprises a polyamide condensation product having a melt-viscosity at 190.degree. C of at least 2000 centipoises.
Dependencies are inferred from the claim text.