Additive manufacturing compositions and methods
A thermosetting composition comprising a crosslinkable component such as a vinyl ester and/or an unsaturated polyester, and an initiator component, such as cumene hydroperoxide or BPO or blends of cumene hydroperoxide and methyl ethyl ketone peroxide. The composition is suitable to be used in additive manufacturing to form objects such as molds or prototypes.
1 . An additive manufacturing composition comprising:
a thermosetting material comprising a cross-linkable component, wherein the cross-linkable component comprises a vinyl ester component or an unsaturated polyester component; and
an initiator of free-radical cross-linking, wherein the initiator is a peroxide system;
wherein, when the composition is deposited in a series of layers, the composition cures without substantial deformation; and
wherein the composition has a rate of enthalpy change of 9 J/g-min or less.
2 . The composition of claim 1 , wherein the composition has a peak exotherm temperature of 50° C. or less during curing as one or more deposited layers.
3 . The composition of claim 1 , wherein the initiator comprises a peroxide selected from cumene hydroperoxide, benzoyl peroxide, or blends of cumene hydroperoxide and methyl ethyl ketone peroxide.
4 . The composition of claim 1 , wherein the composition has a linear shrinkage of 6.0% or less.
5 . The composition of claim 1 , wherein the composition has a total contraction of 15.0% or less.
6 . The composition of claim 1 , wherein the composition is essentially free of low profile agents and shrink control additives.
7 . An object prepared by curing the additive manufacturing composition of claim 1 , wherein the object comprises a plurality of layers.
8 . The object of claim 7 , wherein at least one of the layers has a length in the X and/or Y direction of 1.0 m or more.
9 . An object prepared by curing an additive manufacturing composition,
wherein the additive manufacturing composition comprises:
a thermosetting material comprising a cross-linkable component, wherein the cross-linkable component comprises a vinyl ester component or an unsaturated polyester component; and
an initiator of free-radical cross-linking, wherein the initiator is a peroxide system;
wherein, when the composition is deposited in a series of layers, the composition cures without substantial deformation; and
wherein, when the composition is curing, the composition exhibits a peak exotherm that is no more than 40° C. higher than a temperature at which the composition begins to cure; and
wherein the object comprises a plurality of layers.
10 . The object of claim 9 , wherein at least one of the layers has a length in the X and/or Y direction of 1.0 m or more.
11 . The object of claim 10 , wherein the object comprises at least 10 layers.
12 . A method of additive manufacturing an object comprising:
depositing a first layer of thermosetting material on a support at a deposit temperature;
curing the first layer of the thermosetting material, wherein the peak exotherm temperature during curing is no more than 40° C. higher than the deposit temperature; and
depositing a second layer of thermosetting material on the first layer opposite the support while the first layer undergoes exothermic reaction, and the first layer releases heat to the second layer.
13 . The method of claim 12 , further comprising:
depositing a third layer of the thermosetting material on the second layer and opposite the first layer and the support;
curing the thermosetting material deposited as the third layer; and optionally,
depositing and curing additional layers until the desired height of the object is achieved.
14 . The method of claim 12 , comprising applying a first series of layers, wherein the layers of the first series have a mean peak temperature (MPT) during curing;
depositing a second series, where the MPT of the second series is within 25° C. of the MPT of the first series.
15 . The method of claim 14 wherein the first series releases heat to the second series.
16 . The method of claim 12 , wherein the depositing step comprises depositing the thermosetting material to achieve a layer with a thickness of 1.27 to 12.7 mm.
17 . The method of claim 12 , wherein the curing of the thermosetting material is at atmospheric temperature.
18 . The method of claim 12 , wherein the curing of the thermosetting material is performed without applying secondary energy.
19 . The method of claim 12 , wherein the curing of the thermosetting material is at a temperature of 20° C. to 50° C.
20 . The method of claim 12 , wherein the thermosetting material is deposited onto the support at a temperature between 15 and 30° C., and the support has a temperature between 15 and 30° C.