Photocurable compositions containing reactive polysiloxane particles

Abstract

A photocurable composition, including (a) a cationically curable monomer; (b) a radically curable monomer; (c) reactive particles comprising a crosslinked polysiloxane core and a shell of reactive groups on an outer surface of the core, wherein the reactive groups comprise epoxy groups, ethylenically unsaturated groups, or hydroxy groups; (d) a radical photoinitiator; and (e) a cationic photoinitiator. A method of making a 3-D object from such a composition. A 3-D object made by the method.

We claim:  
     
         1 . A photocurable composition, comprising: 
 (a) a cationically curable monomer;    (b) a radically curable monomer;    (c) reactive particles comprising a crosslinked polysiloxane core and a shell of reactive groups on an outer surface of the core, wherein the reactive groups comprise epoxy groups, ethylenically unsaturated groups, or hydroxy groups;    (d) a radical photoinitiator; and    (e) a cationic photoinitiator.    
     
     
         2 . A composition as claimed in  claim 1 , wherein the core comprises dialkylsiloxane repeating units.  
     
     
         3 . A composition as claimed in  claim 2 , wherein the core comprises dimethylsiloxane repeating units.  
     
     
         4 . A composition as claimed in  claim 1 , wherein the reactive groups comprise epoxy groups.  
     
     
         5 . A composition as claimed in  claim 4 , wherein the reactive particles comprise Albidur EP 2240 or Albidur EP 5340.  
     
     
         6 . A composition as claimed in  claim 1 , wherein the reactive groups comprise ethylenically unsaturated groups.  
     
     
         7 . A composition as claimed in  claim 6 , wherein the reactive particles comprise VE 3320.  
     
     
         8 . A composition as claimed in  claim 1 , wherein the reactive particles have an average particle diameter of from 0.01 and 50 μm.  
     
     
         9 . A composition as claimed in  claim 1 , wherein the reactive particles are capable of reacting substantially completely to form chemical bonds to a polymer matrix that is formed on curing the photocurable composition.  
     
     
         10 . A composition as claimed in  claim 1 , wherein (a) comprises a polyepoxide.  
     
     
         11 . A composition as claimed in  claim 10 , wherein (a) comprises an alicyclic polyepoxide.  
     
     
         12 . A composition as claimed in  claim 11 , wherein the alicyclic polyepoxide has monomer purity of over about 94%.  
     
     
         13 . A composition as claimed in  claim 1 , wherein (b) comprises a poly(meth)acrylate.  
     
     
         14 . A composition as claimed in  claim 13 , comprising a poly(meth)acrylate having a hydroxy group.  
     
     
         15 . A composition as claimed in  claim 13 , wherein (b) comprises a di(meth)acrylate and a poly(meth)acrylate containing at least three (meth)acrylate groups.  
     
     
         16 . A composition as claimed in  claim 1 , further comprising a polyether polyol.  
     
     
         17 . A method comprising: 
 (1) forming a first layer of the photocurable composition of  claim 1;     (2) exposing the first layer to actinic radiation sufficient to harden the first layer;    (3) forming a second layer of the photocurable composition of  claim 1  above the hardened first layer;    (4) exposing the second layer to actinic radiation sufficient to harden the second layer; and    (5) repeating steps (3)-(4) as needed to form a 3-D object.    
     
     
         18 . A method as claimed in  claim 17 , further comprising a step of postcuring the 3-D object.  
     
     
         19 . A 3-D object, prepared by the method of  claim 17 .  
     
     
         20 . The 3-D object of  claim 19 , wherein the 3-D object is opaque.