Methods for reclaiming developing solvents

Abstract

The present invention relates to an improved method for reclaiming and recycling developing solvents used in the production of flexographic printing plates. More specifically, the invention relates to reclaiming and/or recycling of the developing solvent through centrifugation and/or filtration. The reclaiming process can be continuous or batch. The process involves transferring the contaminated solvent, from a plate processor or a dirty holding tank, to a centrifuge and/or filter, and centrifuging and/or filtering the contaminated solvent to remove the polymer. The reclaimed solvent can be transfer directly back to the plate processor or to a clean holding tank.

1 . A method for purifying polymer-containing solvent used in developing printing plates, said method comprising the steps of 
 centrifuging said solvent to separate the polymer from the solvent; and    filtering the solvent.    
   
   
       2 . The method of  claim 1 , wherein the filtering step is accomplished with a vibrational filter.  
   
   
       3 . The method of  claim 1 , wherein the steps comprises a continuous process.  
   
   
       4 . The process of  claim 1 , wherein the process is a batch process.  
   
   
       5 . The method of  claim 1 , wherein the solvent is selected from the group consisting of terpene esters, terpene ethers, alkyl esters, substituted benzenes, and combinations thereof.  
   
   
       6 . The method of  claim 1 , wherein the polymer is selected from the group consisting of block co-polymers of styrene and butadiene, block co-polymers of styrene and isoprene, co-polymers of butadiene and acrylonitrile, terpolymers of butadiene, acrylonitrile, and acrylic acid.  
   
   
       7 . The method of  claim 1 , wherein said solvent further comprises a co-solvent.  
   
   
       8 . The method of  claim 7 , wherein the co-solvent is selected from the group consisting of n-butanol, 2-ethoxyethanol, benzyl alcohol, ethanol, methanol, propanol, isopropanol, alpha terpineol, dipropylene glycol methyl ether, 2-butoxyethanol, isopropyl alcohol, and 2-(2-butoxyethoxy) ethanol, cyclopentanol, cyclohexanol, cycloheptanol, substituted cyclopentanol, substituted cyclohexanol, substituted cycloheptanol, cyclopentyl substituted alcohol, cyclohexyl substituted alcohol, and cycloheptyl substituted alcohol.  
   
   
       9 . The method of  claim 8 , wherein the substituted cyclohexanol is 4-ethycyclohexanol.  
   
   
       10 . The method of  claim 8 , wherein the substituted cyclopentanol is 2,3 dimethylcyclopentanol.  
   
   
       11 . The method of  claim 8 , wherein the cyclohexyl substituted alcohol is cyclohexylpropanol.  
   
   
       12 . The method of  claim 8 , wherein the cyclopentyl substituted alcohol is 4-cyclopentylpentanol.  
   
   
       13 . The method of  claim 1 , wherein said solvent further comprises a non-solvent.  
   
   
       14 . The method of  claim 13 , wherein the non-solvent is selected from the group consisting of aliphatic petroleum distillates, naphthas, paraffinic solvents, hydro-treated petroleum distillates, mineral oil, mineral spirits, ligroin, decane, octane, and hexane.  
   
   
       15 . The method of  claim 14 , wherein the paraffinic solvents are isoparaffins.  
   
   
       16 . The method of  claim 1 , wherein the centrifuge is a bowl disc centrifuge with conical discs.  
   
   
       17 . The method of  claim 1 , wherein the centrifuging step is performed at g forces of at least about 4000.  
   
   
       18 . The method of  claim 1 , wherein the solvent is maintained at about 70° F.  
   
   
       19 . The method of  claim 1 , further comprising the step of adding a precipitant or co-polymerizing material to the solvent.  
   
   
       20 . The method of  claim 1 , further comprising the step of radiating the solvent with a wavelength of light appropriate to crosslink the polymer.