Transparency repair system

Abstract

The present invention provides a composition as well as a method for repairing deep scratches, gouges, etc. and which is particularly useful for aircraft and aerospace transparency repair. The composition is a polishable two-part, solvent-free, composition polyurethane coating for repairing the transparencies and which, after application, cures to a thermoset polyurethane.

1 . A transparency repair composition comprising: a two-part system of:
 (a) a hydroxy-terminated polyol, a light stabilizer and a catalyst defining Part A;   (b) an aliphatic polyisocyanate defining Part B; and   Wherein, when cured, provides a thermoset polyurethane.   
     
     
         2 . The repair composition of  claim 1 , wherein Part A further includes a chain extender comprising a short chain diol. 
     
     
         3 . The composition of  claim 1 , wherein the hydroxy-terminated polyol is either a polyether or polyester polyol having at least two primary hydroxy groups and mixtures thereof. 
     
     
         4 . The composition of  claim 2 , wherein the hydroxy-terminated polyol is a polyester triol terminated by primary hydroxyl groups. 
     
     
         5 . The composition of  claim 4 , wherein the hydroxy-terminated polyol is an aliphatic polyester primary hydroxy-terminated triol. 
     
     
         6 . The composition of  claim 5 , wherein the light stabilizer is a liquid hindered amine light stabilizer. 
     
     
         7 . The composition of  claim 1 , wherein the catalyst is a tin-based catalyst. 
     
     
         8 . The composition of  claim 1 , wherein the diisocyanate is an aliphatic diisocyanate. 
     
     
         9 . The composition of  claim 1 , wherein the first part and second parts are present in respect to weight ratio to about 1:1 to about 1:3. 
     
     
         10 . A method for preparing an aerospace or aircraft transparency repair kit comprising blending together at ambient conditions with stirring for a period of time ranging about twenty seconds to about thirty seconds, the two-part repair kit being the components of  claim 1 . 
     
     
         11 . A method for repairing an aerospace or aircraft transparency comprising:
 (a) applying to the transparency the two-part component system of  claim 1 , (b) thereafter, placing an FEP release film thereover, (c) smoothing the FEP film over the repair composition and, (d) after about two hours removing the film and (e) allowing the coating to cure.