Branched reactive blocked prepolymers for additive manufacturing

A three-dimensional object produced by a method comprising:

• (a) producing an intermediate object from a polymerizable liquid by additive manufacturing, said polymerizable liquid comprising a mixture of:
• (i) a first blocked or reactive blocked prepolymer comprising a compound of the formula X(A)n, wherein X is an aliphatic and/or aromatic group containing N and O heteroatoms and carbonyl groups, n is at least 3, and each A is an independently selected substituent of Formula I:
• wherein R is a hydrocarbyl group, R′ is O or NH, and Z is a blocking group;
• (ii) a polyol and/or polyamine chain extender;
• (iii) optionally a reactive diluent;
• and
• (iv) a photoinitiator;
• (b) optionally cleaning said intermediate object;
• and then
• (c) heating and/or microwave irradiating said intermediate object for a time sufficient to further cure said intermediate object and form said three-dimensional object.

A polymerizable liquid useful for the production of a three-dimensional object comprised of polyurethane, polyurea, or a copolymer thereof by additive manufacturing, said polymerizable liquid comprising a mixture of:

• (a) a first blocked or reactive blocked prepolymer comprising a compound of the formula X(A)n, wherein X is a hydrocarbyl group, n is at least 3, and each A is an independently selected substituent of Formula I:
• wherein R is a hydrocarbyl group, R′ is O or NH, and Z is a blocking group;
• (b) a polyol and/or polyamine chain extender;
• (c) optionally a reactive diluent;
• and
• (d) a photoinitiator;
• (e) a second blocked or reactive blocked prepolymer comprising a compound of the formula A′-X′-A′, where X′ is a hydrocarbyl group and each A′ is an independently selected substituent of Formula I′:
• wherein R″ is a hydrocarbyl group, R′″ is O or NH, and Z′ is a blocking group, said blocking group optionally having a reactive epoxy, alkene, alkyne, or thiol terminal group;
• and
• (f) a third blocked or reactive blocked prepolymer, wherein the third blocked or reactive blocked prepolymer comprises the compounds:
• wherein x=6.