Solvent-activated color forming compositions

Abstract

Color-forming compositions comprising (i) a solvent absorbing material such as a polymer; (ii) a color-former or chelating agent compounded with the solvent absorbing material; and (iii) a source of metal ions, whereby the metal ions complex with the color former as the solvent absorbing material absorbs the solvent, resulting in a detectable color change of the solvent absorbing material. Both reversible and irreversible versions of these color-forming compositions are provided.

1 . A solvent-activated, color-forming composition, comprising: 
 (a) a solvent-absorbing material;    (b) a color former compounded with said solvent-absorbing material, wherein said color former is a chelating agent; and    (c) a source of metal ions capable of complexing with said color former as said solvent-absorbing material absorbs said solvent, resulting in a detectable color change of said solvent-absorbing material.    
     
     
         2 . The color-forming composition of  claim 1 , wherein said solvent is polyethylene acrylic acid ionomer containing about 5% titanium dioxide filler resin; said color former is about 0.15% to 2.0% 1,2-Dihydroxybenzene; and said source of metal ions is about 0.25% to 2.0% zinc acetate.  
     
     
         3 . A color-forming composition, comprising: 
 (a) a solvent;    (b) a solvent-absorbing material;    (c) a color former compounded with said solvent-absorbing material, wherein said color former is a chelating agent; and    (d) a source of metal ions capable of complexing with said color former as said solvent-absorbing material absorbs said solvent, resulting in a detectable color change of said solvent absorbing material.    
     
     
         4 . The color-forming composition of  claim 3 , wherein said color-forming composition exhibits thermoxidative stability at compounding temperatures of at least 104° C.  
     
     
         5 . The color-forming composition of  claim 3 , wherein said color-forming composition exhibits thermoxidative stability at extrusion temperatures of at least 207° C.  
     
     
         6 . The color-forming composition of  claim 3 , wherein said solvent is water.  
     
     
         7 . The color-forming composition of  claim 3 , wherein in said solvent is an inorganic solvent.  
     
     
         8 . The color-forming composition of  claim 3 , wherein in said solvent is an organic solvent.  
     
     
         9 . The color-forming composition of  claim 3 , wherein said solvent absorbing material is a polymer or a polymer composite.  
     
     
         10 . The color-forming composition of  claim 9 , wherein said polymer is polyethylene acrylic acid ionomer containing about 5% titanium dioxide filler resin.  
     
     
         11 . The color-forming composition of  claim 3 , wherein said solvent absorbing material is paint.  
     
     
         12 . The color-forming composition of  claim 3 , wherein said solvent absorbing material is a synthetic construction material selected from the group consisting of polyvinyl chloride, polyurethane, silicone elastomers, and organic rubbers.  
     
     
         13 . The color-forming composition of  claim 3 , wherein said color former is 1,2-Dihydroxybenzene.  
     
     
         14 . The color-forming composition of  claim 13 , wherein said color change is not reversed by the removal of said solvent from said solvent-absorbing material.  
     
     
         15 . The color-forming composition of  claim 3 , wherein said color former is an aromatic di-hydroxy compound.  
     
     
         16 . The color-forming composition of  claim 15 , wherein said color change is not reversed by the removal of said solvent from said solvent-absorbing material.  
     
     
         17 . The color-forming composition of  claim 15 , wherein said aromatic dihydroxy compound is selected from the group consisting of 3-Methylcatechol, 4-Methylcatechol, 4,5-Dihydroxy 1,3-benzenedisulfonic acid disodium salt and 1,2,3-Trihydroxybenzene.  
     
     
         18 . The color-forming composition of  claim 17 , wherein said color change is not reversed by the removal of said solvent from said solvent-absorbing material.  
     
     
         19 . The color-forming composition of  claim 3 , wherein said chelating agent is a diethylaminofluroan based dye or a diethylamino analog.  
     
     
         20 . The color-forming composition of  claim 19 , wherein said color change is reversed by the removal of said solvent from said solvent-absorbing material.  
     
     
         21 . The color-forming composition of  claim 3 , wherein said source of metal ions is said solvent.  
     
     
         22 . The color-forming composition of  claim 3 , wherein said source of metal ions is said solvent-absorbing material.  
     
     
         23 . The color-forming composition of  claim 3 , wherein said source of metal ions is a metal salt.  
     
     
         24 . The color-forming composition of  claim 3 , wherein said metal ions are zinc ions.  
     
     
         25 . The color-forming composition of  claim 3 , wherein said metal ions are iron, sodium, calcium, magnesium, lithium, titanium, or magnesium ions.  
     
     
         26 . A method of making a color-forming composition, comprising the steps of: 
 (a) providing a solvent-absorbing material, a chelating agent, and a source of metal ions;    (b) dry blending said solvent-absorbing material, said chelating agent, and said metal ions in a batch process; and    (c) compounding said batch in an extruder or other suitable mixing device.    
     
     
         27 . A method of making a color-forming composition, comprising the steps of: 
 (a) providing a solvent-absorbing material, a chelating agent, and a source of metal ions; and    (b) metering said solvent-absorbing material, said chelating agent, and said metal ions into an extruder or other continuously compounding device.    
     
     
         28 . A method of making a color-forming composition, comprising the steps of: 
 (a) providing a solvent-absorbing material, a chelating agent, and a source of metal ions; and    (b) dry blending or continuously metering said solvent-absorbing material, said chelating agent, and said source of metal ions into the final processing step, wherein said final processing step has a minimum amount of mixing capability.    
     
     
         29 . A method of making a color-forming composition, comprising the steps of: 
 (a) providing a solvent-absorbing material, a chelating agent, and a source of metal ions; and    (b) at the final fabrication step, adding said chelating agent and said source of metal ions to said solvent absorbing material at a level higher than that required for the desired final concentration of said chelating agent and said source of metal ions in said solvent-absorbing material.    
     
     
         30 . A method for indicating exposure of a material to a solvent, comprising: 
 (a) providing a solvent;    (b) providing a solvent-absorbing material;    (c) compounding a color-former with said solvent-absorbing material, wherein said color-former is a chelating agent;    (d) providing a source of metal ions; and    (e) contacting said solvent-absorbing material with said solvent, whereby as said solvent is absorbed by said solvent-absorbing material, said metal ions contact and complex with said color-former resulting in a detectable color change of said solvent-absorbing material.