Ex Parte Robeson et al - Page 7

                Appeal 2007-2910                                                                             
                Application 10/304,881                                                                       
           1    secondary considerations guard against the employment of impermissible                       
           2    hindsight.20                                                                                 

           3                       The scope and content of the prior art                                    
           4          The Robeson patent teaches a curable polymer emulsion composition                      
           5    containing a blend of an epoxy polymer and a vinyl acetate polymer.  An                      
           6    amine curative can be used for long-term stability.21  Robeson explains that                 
           7    epoxy resins must be cured with a suitable hardener, generally an amine, but                 
           8    that combining them in a water-based solution reduces storage stability.22                   
           9    Robeson reports that the problem can be overcome by using                                    
          10    isophoronediamine (IPDA) as the amine curative for the epoxy resin.23                        
          11    Robeson's improved composition is said to be suitable for coatings and                       
          12    adhesives.24                                                                                 
          13          Robeson teaches that a broad range of epoxy resins could be used, but                  
          14    the preferred epoxy resin is the diglycidyl ether of bisphenol A.  The "di-"                 
          15    prefix in diglycidyl ether simply means that there are two glycidyl ether                    
          16    groups, one formed at each hydroxyl of the bisphenol A moiety.25  Robeson                    


                                                                                                            
                20 Graham v. John Deere Co., 383 U.S. 1, 17, 36 (1966), cited with approval                  
                in KSR Int'l v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007). The                   
                record on appeal does not contain objective evidence of secondary                            
                considerations.                                                                              
                21 Robeson 1:14-23.                                                                          
                22 Robeson 1:37-44.                                                                          
                23 Robeson 2:52-58.  Air Products' dependent claims 14 and 15 permit and                     
                require, respectively, that the amine be IPDA.                                               
                24 Robeson 3:9:13.                                                                           
                25 Robeson 4:18-20.  Where the bisphenol A is a repeating unit in a polymer                  
                chain, the glycidyl ethers are formed at the terminal hydroxyls.                             
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