Radiation curable compositions for additive fabrication with improved toughness and high temperature resistance

Abstract

Radiation curable compositions for additive fabrication with improved toughness are described and claimed. Such resins include a rubber toughenable base resin package and a liquid, phase-separating toughening agent. The rubber toughenable base resin, which may possess a suitably high average molecular weight between crosslinks and may be a pre-reacted hydrophobic macromolecule, may further include a cationically polymerizable component, a radically polymerizable component, a cationic photoinitiator, a free radical photoinitiator, and customary additives. Also described and claimed are methods for forming a three-dimensional objects using such radiation curable compositions for additive fabrication with improved toughness, along with the three-dimensional parts created therefrom.

1 . A radiation curable composition for additive fabrication with improved toughness comprising:
 a rubber toughenable base resin further comprising
 a cationically polymerizable component; 
 a radically polymerizable component; 
 a cationic photoinitiator; 
 a free radical photoinitiator; and 
 optionally, customary additives; and 
   a liquid phase-separating toughening agent;   wherein the liquid phase-separating toughening agent is present in an amount, relative to the weight of the rubber toughenable base resin, in a ratio from 1:99 to about 1:9, and   wherein the average molecular weight between crosslinks (M C ) of the rubber toughenable base resin is greater than 130 g/mol.   
     
     
         2 . The radiation curable composition for additive fabrication with improved toughness of  claim 1 , wherein the liquid phase-separating toughening agent is a high molecular weight dimer fatty acid polyol. 
     
     
         3 . The radiation curable composition for additive fabrication with improved toughness of  claim 1 , wherein the high molecular weight polyol is selected to be configured to form, after curing of the radiation curable composition, phase domains with an average size of from about 2 microns to about 25 microns when measured according to an Average Phase Domain Size Procedure. 
     
     
         4 . The radiation curable composition for additive fabrication with improved toughness of  claim 1 , wherein the high molecular weight dimer fatty acid polyol possesses a molecular weight of greater than 8000 g/mol. 
     
     
         5 . The radiation curable composition for additive fabrication with improved toughness of  claim 4 , wherein the high molecular weight dimer fatty acid polyol is a propylene oxide or ethylene oxide. 
     
     
         6 . The radiation curable composition for additive fabrication with improved toughness of  claim 1 , wherein M C  of the rubber toughenable base resin is less than 500 g/mol. 
     
     
         7 . The radiation curable composition for additive fabrication with improved toughness of  claim 6 , wherein a three-dimensional component created therefrom by means of an additive fabrication process yields an elongation value that is at least 50% greater than a corresponding elongation value of a three dimensional component created from the constituent rubber toughenable base resin of said radiation curable composition. 
     
     
         8 . The radiation curable composition for additive fabrication with improved toughness of  claim 7 , wherein a three-dimensional component created therefrom by means of an additive fabrication process yields an HDT value that is within at least 5 degrees Celsius of a corresponding elongation value of a three dimensional component created from the constituent rubber toughenable base resin of said radiation curable composition. 
     
     
         9 . A radiation curable composition for additive fabrication with improved toughness comprising:
 a rubber toughenable base resin further comprising
 (1) optionally, a cationically polymerizable component; 
 (2) a radically polymerizable component; 
 (3) optionally, a cationic photoinitiator; 
 (4) a free radical photoinitiator; and 
 (5) optionally, customary additives; and 
   a liquid phase-separating toughening agent;   wherein the liquid phase-separating toughening agent is an epoxidized pre-reacted hydrophobic macromolecule;   wherein the average molecular weight between crosslinks (M C ) of the rubber toughenable base resin is greater than 180 g/mol; and   wherein the M C  of the rubber toughenable base resin is less than 260 g/mol.   
     
     
         10 . The radiation curable composition for additive fabrication with improved toughness of  claim 9 , wherein the rubber toughenable base resin further contains, relative to the entire weight of the rubber toughenable base resin, of
 less than about 40 wt. % of at least one aromatic glycidyl epoxy, and   at least about 5 wt. % of a polyol component.   
     
     
         11 . The radiation curable composition for additive fabrication with improved toughness of  claim 10 , wherein the epoxidized pre-reacted hydrophobic macromolecule is a triblock copolymer possessing
 terminating epoxy- or acrylate-functional hard blocks; and   at least one immiscible soft block.   
     
     
         12 . The radiation curable composition for additive fabrication with improved toughness of  claim 11 , wherein the triblock copolymer is formed by the reaction product of
 a soft-block originator with   a monofunctional anhydride such as hexahydrophthalic anhydride,   and then further reacting an epoxy-functional reactant.   
     
     
         13 . The radiation curable composition for additive fabrication with improved toughness of  claim 12 , wherein the soft-block originator is selected from the group consisting of polybutadienes, polyols, and polydmethylsiloxanes, and any combination thereof. 
     
     
         14 . The radiation curable composition for additive fabrication with improved toughness of  claim 9 , wherein the epoxidized pre-reacted hydrophobic macromolecule is derived from a triglyceride fatty acid. 
     
     
         15 . The radiation curable composition for additive fabrication with improved toughness of  claim 9 , wherein the epoxidized pre-reacted hydrophobic macromolecule is derived from a tall oil, wherein the epoxidized tall oil is an epoxidized vegetable oil, such as soybean or linseed oil. 
     
     
         16 . The radiation curable composition for additive fabrication with improved toughness of  claim 9 , wherein the epoxidized pre-reacted hydrophobic macromolecule is derived from a compound of the following formula: 
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , and R 3  are the same or different, and are each a C 4 -C 50  unsaturated alkyl chain, wherein the unsaturation has been at least 30% epoxidized. 
       
     
     
         17 . The radiation curable composition for additive fabrication with improved toughness of  claim 9 , wherein the epoxidized pre-reacted hydrophobic macromolecule possesses a molecular weight of from about 800 g/mol to about 4000 g/mol. 
     
     
         18 . The radiation curable composition for additive fabrication with improved toughness of  claim 17 , wherein the epoxidized pre-reacted hydrophobic macromolecule is present, relative to the weight of the entire composition, in an amount from about 1% to about 20%, more preferably from about 1.5% to about 12%. 
     
     
         19 . A process of forming a three-dimensional object comprising the steps of forming and selectively curing a liquid layer of the radiation curable composition for additive fabrication with improved toughness of any one of  claims 1 - 18  with actinic radiation and repeating the steps of forming and selectively curing the liquid layer of the radiation curable composition for additive fabrication of any one of  claims 1 - 18  a plurality of times to obtain a three-dimensional object. 
     
     
         20 . (canceled)