Retroreflective inks

Abstract

The combination of ingredients, especially for use in the formulation of a one or two-pack retroreflective ink, comprising retroreflective elements, microbeads additional to said retroreflective elements and/or constituting said retroreflective elements at least in part, binder chemicals for attaching the retroreflective elements and microbeads to a substrate to which the ink is to be applied, and a coupling agent for coupling the microbeads and cross-linking the binder chemicals, the coupling agent being unreactive until the printing process is carried out.

1 - 56 . (canceled)  
     
     
         57 . A combination of ingredients forming a retroreflective ink, the combination comprising metallised retroreflective elements, microbeads additional to said retroreflective elements and/or constituting said retroreflective elements at least in part, binder chemicals for attaching the retroreflective elements and microbeads to a substrate to which the ink is to be applied, a coupling agent for coupling the microbeads and cross-linking the binder chemicals, and a buffer, the coupling agent being unreactive and uncured until a curing step is carried out and reactive when the curing step is carried out during which a temperature of the substrate and ink applied to the substrate is elevated to between 60 and 200° C., the coupling agent having a storage life of not less and about 3 months and being unreactive except at elevated temperature of the curing step, the coupling agent being selected from the group consisting of an aminoalkyl silanetriol and a blocked polyisocyanate.  
     
     
         58 . The combination of ingredients according to  claim 57 , wherein the buffer is a phosphate buffer.  
     
     
         59 . The combination of ingredients according to  claim 58 , wherein the phosphate buffer is an ammonium phosphate buffer.  
     
     
         60 . The combination of ingredients according to  claim 58 , wherein the phosphate buffer is a sodium phosphate buffer.  
     
     
         61 . The combination of ingredients according to  claim 57 , wherein the binder is a polyvinylidene chloride copolymer and the coupling agent is an aminoalkyl silanetriol.  
     
     
         62 . The combination of ingredients according to  claim 57 , wherein the binder is an acrylic copolymer and the coupling agent is an aminoalkyl silanetriol.  
     
     
         63 . The combination of ingredients according to  claim 57 , wherein the binder is polyurethane and the coupling agent is a blocked hexamethylene diisocynate trimer.  
     
     
         64 . The combination of ingredients according to  claim 57 , wherein the binder is a non-flammable plastisol.  
     
     
         65 . The combination of  claim 64 , wherein the non-flammable plastisol is polyvinylidene chloride.  
     
     
         66 . The combination of  claim 64 , wherein the non-flammable plastisol is polyvinyl chloride.  
     
     
         67 . The combination of ingredients according to  claim 57 , additionally including a humectant.  
     
     
         68 . The combination of ingredients according to  claim 67 , wherein the humectant is urea.  
     
     
         69 . The combination of ingredients according to  claim 67 , wherein the humectant is a combination of urea and 2,3 propane diol.  
     
     
         70 . The combination of  claim 57 , wherein the combination comprises a one pack retroreflective ink.  
     
     
         71 . The combination of  claim 57 , wherein at least some of the microbeads are without the retroreflective elements.  
     
     
         72 . The combination of  claim 57 , wherein a polyvinylidene chloride copolymer is the binder chemical and a mixture of an aminoalkyl silanetriol and a blocked hexamethylene diisocyanate trimer is the coupling agent.  
     
     
         73 . The combination of  claim 57 , further comprising one or more components selected from the group consisting of: 
 pigment, dispersant, defoamer, thickening agent, cross-linking agent, softening agent, carbon black, UV absorbing material, anti-scuffing agent, a silicone or fluoropolymer, light spill-suppressing agent, anti-static agent, water repellent agent, a silicone, and a fluoropolymer.    
     
     
         74 . The combination of  claim 57 , wherein the volume ratio of the binder to the microbeads is equal to or less than 50%.  
     
     
         75 . The combination of  claim 57 , wherein essentially all of the microbeads are unmetallised and the retroreflective elements include reflective flake particles.  
     
     
         76 . The combination of  claim 57 , wherein the binder forms at least part of a liquid carrier medium for the retroreflective elements or microbeads.  
     
     
         77 . The combination of  claim 57 , wherein the binder chemicals, retroreflective elements and microbeads are comprised of a one-pack retroreflective ink or a two-pack retroreflective ink having the coupling agent as the second pack.  
     
     
         78 . The combination of  claim 77 , wherein the two-pack ink includes a reactive polyisocyanate or an alkoxysilyl alkyl derivative.  
     
     
         79 . The combination of  claim 57 , wherein the microbeads are metallised with an aluminum coating that is superposed on a stannous chloride pre-treatment.  
     
     
         80 . The combination of  claim 79 , wherein the metallised microbeads are treated with a solution of a silicate, followed by treatment with a silane.  
     
     
         81 . The combination of  claim 80 , wherein the microbeads have at least one of the following characteristics selected from the group consisting of: a refractive index in the range of about 1.8 to 2.2, a median size of the microbeads in the range of about 10 to 100 microns and the microbeads are composed of titanium glass or barium glass.  
     
     
         82 . The combination of  claim 79 , wherein the metallised microbeads are treated with an amino silane.  
     
     
         83 . A composition that a is one-pack or a two-pack retroreflective ink which is comprised of the combination claimed in  claim 57 .  
     
     
         84 . The composition of  claim 83 , wherein the ink has a viscosity of between 10 and 30 Pascal seconds at room temperature.  
     
     
         85 . The composition of  claim 83 , wherein the retroreflective ink is water-based.  
     
     
         86 . The composition of  claim 85  that is suitably formulated for screen printing.  
     
     
         87 . The composition of  claim 83 , wherein the ink has a viscosity that is less than or equal to about 40 Pascal seconds at room temperature.  
     
     
         88 . The composition of  claim 57 , wherein the coupling agent has a storage life of not less than about 3 months and is unreactive except at elevated temperature of between 130 and 180° C. at which the one-pack retroreflective ink printed on the substrate is cured.  
     
     
         89 . A method for making a one-pack retroreflective ink comprising the steps of: 
 (a) making metallised microbeads; and    (b) suspending the microbeads in a liquid carrier medium, the liquid carrier medium being comprised of binder chemicals for attaching the microbeads to a substrate to which the ink is to be applied, a coupling agent which couples the microbeads and cross-links the binder chemicals, and a buffer, the one-pack retroreflective ink having a storage life of not less than about 3 months and the coupling agent being unreactive and uncured until a curing step is carried out and reactive when the curing step is carried out during which a temperature of the substrate and ink applied to the substrate is elevated to between 60 and 200° C., the coupling agent having a storage life of not less than about 3 months and being unreactive except at elevated temperature of the curing step, the coupling agent being selected from the group consisting of an aminoalkyl silanetriol and a blocked polyisocyanate.    
     
     
         90 . The method of  claim 89 , wherein step (a) includes applying an aluminium coating to the microbeads.  
     
     
         91 . The method of  claim 90 , wherein step (a) includes pre-treating the microbeads with stannous chloride prior to application of the aluminium coating.  
     
     
         92 . The method of  claim 89 , wherein step (a) includes treating the microbeads with a silane or an amino silane prior to inclusion in the ink.  
     
     
         93 . The method of  claim 89 , wherein step (a) includes hemispherically metallising the microbeads in a vacuum metallising process in which the microbeads are held on a film with an adhesive coating for transport through the metallising process, the adhesive coating is comprised of styrene-butadiene type adhesive.  
     
     
         94 . The method according to  claim 93 , wherein step (a) includes passing the film through an aqueous solution of citric acid after metallisation.  
     
     
         95 . The method of  claim 93 , wherein step (a) includes ultrasonically treating the film to assist in release of the microbeads from the adhesive.  
     
     
         96 . The method of  claim 91 , wherein step (a) includes treating the microbeads with a dilute aqueous solution of stannous chloride.  
     
     
         97 . The method of  claim 96 , wherein step (a) includes treating the microbeads prior to inclusion in the ink with a silicate.  
     
     
         98 . The method of  claim 97 , wherein step (a) includes treating the microbeads with an amino silane after the silicate treatment.  
     
     
         99 . The method of  claim 98 , wherein the microbeads have at least one of the following characteristics selected from the group consisting of: a refractive index in the range of about 1.8 to 22., a median size of the microbeads in the range of about 10 to 100 microns and the microbeads are composed of titanium glass or barium glass.  
     
     
         100 . The method of  claim 89 , wherein step (b) includes preparing the liquid carrier medium from the binder chemicals and the coupling agent before suspending the microbeads in the liquid carrier medium.  
     
     
         101 . The method of  claim 100 , wherein the liquid carrier medium of step (b) includes additives selected from the group consisting of: 
 pigment, dispersant, defoamer, thickening agent, cross-linking agent, softening agent, carbon black, UV absorbing material, anti-scuffing agent, silicone, fluoropolymer, light spill-suppressing agent, anti-static agent and water repellent agent.    
     
     
         102 . The method of  claim 101 , wherein step (b) includes adding a thickener to the liquid carrier medium before or after the addition of the binder chemicals and coupling agent.  
     
     
         103 . A composition of an ink produced by the method of  claim 89 .  
     
     
         104 . A composition of a substrate coated or printed with a composition of  claim 103 .  
     
     
         105 . The composition of  claim 104 , wherein the substrate is a screen for displaying projected images or a studio background for chroma-keying applications.  
     
     
         106 . The composition of  claim 104 , wherein the substrate is a flexible tape.  
     
     
         107 . The method of providing a substrate having a retroreflective coating, comprising the steps of: 
 applying to the substrate an ink as claimed in  claim 103 , wherein the ink is formulated as a one-pack retroreflective ink and the coupling agent is activated after the ink is printed or coated on to the substrate.    
     
     
         108 . The method of  claim 107 , wherein the coupling agent is activated by curing the ink coating at elevated temperature.  
     
     
         109 . The method of  claim 107 , wherein the coupling agent is activated by UV light or other high energy radiation during or after the printing process.  
     
     
         110 . The composition of  claim 103 , wherein the ink is a retroreflective one-pack ink having a storage life of not less than about 3 months.  
     
     
         111 . The composition of  claim 110 , wherein the retroreflective one-pack ink has a viscosity of between about 10 and 30 Pascal seconds after storage of not less than about 3 months.  
     
     
         112 . The composition of  claim 110 , wherein the retroreflective one-pack ink applied to the substrate and cured has a laundering durability such that the retroreflectivity is not reduced by more than about 40% when the substrate is in the form of a cotton, nylon or polyester fabric and laundered for 5 cycles in accordance with ISO 6330, method  5 A.  
     
     
         113 . The method of  claim 89 , wherein the coupling agent has a storage life of not less than about 3 months and is unreactive except at elevated temperature of between 130 and 180° C. at which the one-pack retroreflective ink printed on the substrate is cured.  
     
     
         114 . The method of  claim 89 , wherein the liquid carrier medium of step (b) includes a phosphate buffer.  
     
     
         115 . The method of  claim 114 , wherein the phosphate buffer is an ammonium phosphate buffer.  
     
     
         116 . The method of  claim 114 , wherein the phosphate buffer is a sodium phosphate buffer.  
     
     
         117 . The method of  claim 89 , wherein the liquid carrier medium of step (b) additionally includes a humectant.  
     
     
         118 . The method of  claim 117 , wherein the humectant is urea.  
     
     
         119 . The method of  claim 117 , wherein the humectant is a combination of urea and 2,3 propane diol.  
     
     
         120 . The method of  claim 89 , wherein the binder of the liquid carrier medium is a non-flammable plastisol.  
     
     
         121 . The method of  claim 120 , wherein the non-flammable plastisol is polyvinylidene chloride.  
     
     
         122 . The method of  claim 120 , wherein the non-flammable plastisol is polyvinyl chloride.  
     
     
         123 . A combination of ingredients forming a retroreflective ink, the combination comprising retroreflective elements, microbeads additional to said retroreflective elements and/or constituting said retroreflective elements at least in part, binder chemicals for attaching the retroreflective elements and microbeads to a substrate to which the ink is to be applied, and a coupling agent for coupling the microbeads and cross-linking the binder chemicals, the coupling agent being unreactive and uncured until a curing step is carried out and reactive when the curing step is carried out during which a temperature of the substrate and ink applied to the substrate is elevated to between 60 and 200° C., the coupling agent having a storage life of not less than about 3 months and being unreactive except at elevated temperature of the curing step, the coupling agent being selected from a group consisting of an aminoalkyl silanetriol and a combination of aminoalkyl silanetriol and blocked polyisocyanate and wherein the ink retains a viscosity of between 10 and 30 Pascal seconds for not less than 3 months.  
     
     
         124 . A method for making a one-pack retroreflective ink comprising the steps of: 
 (a) making metallised microbeads; and    (b) suspending the microbeads in a liquid carrier medium, the liquid carrier medium being comprised of binder chemicals for attaching the microbeads to a substrate to which the ink is to be applied and a coupling agent which couples the microbeads and cross-links the binder chemicals, the one-pack retroreflective ink having a storage life of not less than about 3 months and the coupling agent being unreactive and uncured until a curing step is carried out and reactive when the curing step is carried out during which a temperature of the substrate and ink applied to the substrate is elevated to between 60 and 200° C., the coupling agent having a storage life of not less than about 3 months and being unreactive except at elevated temperature of the curing step, the coupling agent being selected from a group consisting of an aminoalkyl silanetriol and a combination of aminoalkyl silanetriol and block polyisocyanate; and    wherein the ink retains a viscosity of between 10 and 30 Pascal seconds for not less than 3 months.