Three-dimensional printing combining ring-opening metathesis polymerization and free radical polymerization

A method of fabricating a three-dimensional object, the method comprising sequentially forming a plurality of layers in a configured pattern corresponding to the shape of the object, thereby forming the object,

• wherein forming at least one of said layer comprises:
• (i) dispensing by at least one inkjet printing head at least one modeling material formulation, said at least one modeling material formulation comprising:
• an unsaturated cyclic monomer polymerizable by ring opening metathesis polymerization (ROMP);
• a catalyst or a catalyst system comprising a catalyst for initiating ROMP of said monomer;
• a curable material polymerizable by free-radical polymerization (FRP);
• and
• a curing agent (or system) for initiating free radical polymerization of said curable material;
• (ii) exposing said at least one modeling material formulation to a condition for inducing initiation of ROMP of said monomer by said catalyst;
• (iii) maintaining said formulation at a first temperature for a first time period;
• and
• (iv) subsequent to said first time period, exposing the modeling material formulation to a condition for inducing initiation of free-radical polymerization of said curable material by said curing agent, said condition for inducing initiation of said free radical polymerization comprising a second temperature, wherein said second temperature is higher than said first temperature,
• to thereby obtain a cured modeling material in said layer.

A method of fabricating a three-dimensional object, the method comprising sequentially forming a plurality of layers in a configured pattern corresponding to the shape of the object, thereby forming the object,

• wherein forming each of said layer comprises:
• (i) dispensing by at least one inkjet printing head at least one modeling material formulation, said at least one modeling material formulation comprising:
• an unsaturated cyclic monomer polymerizable by ring opening metathesis polymerization (ROMP);
• a catalyst or a catalyst system comprising a catalyst for initiating ROMP of said monomer;
• a curable material polymerizable by free-radical polymerization;
• and
• a curing agent (or system) for initiating free radical polymerization of said curable material;
• (ii) exposing said at least one modeling material formulation to a condition for inducing initiation of ROMP of said monomer by said catalyst;
• (iii) maintaining said at least one modeling material formulation at a first temperature;
• and
• (iv) exposing the modeling material formulation to a condition for inducing initiation of free-radical polymerization of said curable material by said curing agent, said condition for inducing initiation of said free radical polymerization comprising a second temperature,
• to thereby obtain a cured modeling material in said layer,
• wherein said curing agent is such that its half life at said first temperature, t1/2CT, and a time period in which 80% of said unsaturated cyclic monomer undergo polymerization by said ROMP at said first temperature (CT), tc80, satisfy 2.5 times tc80<t1/2CT<1000 times tc80.

A system for three-dimensional inkjet printing, comprising:

• a plurality of inkjet printing heads;
• a heating system configured for heating a building material formulation dispensed by said printing heads;
• and
• a controller configured for controlling said inkjet printing heads to dispense droplets of said building material formulation in layers, such as to print a three-dimensional object on said tray, and for controlling said heating system to first maintain a first temperature for a first time-period, and then maintain a second temperature for a second time-period, said second temperature being higher than said first temperature.