Laser-sensitive coating formulations
The present invention provides polymeric particles comprising a polymeric matrix comprising one or more water-insoluble polymers and a laser-sensitive system encapsulated in the polymeric matrix. It also provides a process for the preparation of the polymeric particles, a composition comprising the polymeric particles, a process for the preparation of this composition, a process for forming a laser-sensitive coating layer on a substrate using this composition, a coated substrate obtainable by the coating process, a process for preparing a marked substrate and a marked substrate obtainable by the marking process.
1. A particle comprising:
(i) a polymeric matrix comprising one or more water-insoluble polymers; and
(ii) a laser-sensitive system comprising an ammonium salt,
wherein the laser-sensitive system is encapsulated in the polymeric matrix, and
wherein at least one of the one or more water-insoluble polymers of the polymeric matrix is cross-linked.
2. The particle of claim 1 , wherein the ammonium salt is at least one of ammonium dimolybdate and ammonium octamolybdate.
3. A process for the preparation of the particle of claim 1 , the process comprising:
mixing the laser-sensitive system with a water-soluble monomer mixture, prepolymer or polymer, optionally in the presence of one or more water-insoluble polymers; and
forming a cross-linked water-insoluble polymer from the water-soluble monomer mixture, prepolymer or polymer and thus effecting encapsulation of the laser-sensitive system in a polymeric matrix.
4. The process of claim 3 , wherein the laser-sensitive system is mixed with a water-soluble prepolymer, optionally in the presence of one or more water-insoluble polymers, and the water-insoluble polymer is formed from the water-soluble prepolymer by crosslinking the prepolymer.
5. The process of claim 3 , wherein the laser-sensitive system is mixed with a water-soluble polymer carrying acidic or basic functional groups in their salt forms, optionally in the presence of one or more water-insoluble polymers, and the water-insoluble polymer is formed from the water-soluble polymer by altering the pH.
6. The process of claim 3 , wherein the laser-sensitive system is mixed with a water-soluble polymer carrying functional groups capable of crosslinking with a crosslinking agent, optionally in the presence of one or more water-insoluble polymers, and the water-insoluble polymer is formed from the water-soluble polymer carrying the functional groups by addition of the crosslinking agent.
7. A composition comprising:
at least one particle comprising (i) a polymeric matrix comprising one or more water-insoluble polymers, and (ii) a laser-sensitive system comprising an ammonium salt and a polymeric binder,
wherein the laser-sensitive system is encapsulated in the polymeric matrix, and
wherein at least one of the one or more water-insoluble polymers of the polymeric matrix is cross-linked.
8. A substrate coated with the composition of claim 7 .
9. A process for preparing a marked substrate, the process comprising:
providing a substrate coated with a composition comprising at least one particle comprising (i) a polymeric matrix comprising one or more water-insoluble polymers, and (ii) a laser-sensitive system comprising an ammonium salt and a polymeric binder, wherein the laser-sensitive system is encapsulated in the polymeric matrix, and wherein at least one of the one or more water-insoluble polymers of the polymeric matrix is cross-linked; and
exposing those parts of the coated substrate, where a marking is intended, to energy in order to generate a marking.
10. A marked substrate obtained by the process of claim 9 .