Thermosetting compositions and forming three-dimensional objects therefrom
Thermoset compositions and methods for forming three-dimensional articles via an additive fabrication process, and articles made therefrom are disclosed herein. In an embodiment, a composition comprises a first network-forming component comprising a first oligomer comprising a backbone and having at least 2 polymerizable groups, one or more first network monomers, and a first network initiator. The backbone of the first oligomer comprises a polyepoxide based on Bisphenol A, F, or S, a polyepoxide based on hydrogenated Bisphenol A, F, or S, a polycarbonate, or a polyimide. The composition may further comprise a second network-forming component.
1. A composition for forming a three-dimensional object via an additive fabrication process comprising:
a. from 30 to 100 wt %, based on the total weight of the composition, of a first network-forming component comprising:
i. from 19.95 to 80 wt %, based on the total weight of the first network-forming component, of a first oligomer comprising a backbone comprising a polyepoxide based on Bisphenol A, F, or S, a polyepoxide based on hydrogenated Bisphenol A, F, or S, a polycarbonate, or a polyimide, and having a number average of at least 2 polymerizable groups, wherein the polymerizable groups comprise acrylate, methacrylate, itaconate, vinyl ether, allyl ether, maleate, or fumarate, and wherein the first oligomer has a number average molecular weight of from 800 to 10000 g/mol and a Tg of 25° C. or more;
ii. from 19.95 to 80 wt %, based on the total weight of the network-forming component, of one or more first network monomers having a number average of 0.95 to 1.1 polymerizable groups that are able to (co)polymerize with the polymerizable groups of the first oligomer, wherein a linear polymer formed from the one or more first network monomers has a Tg of 25° C. or more;
iii. from 0.05 to 5 wt %, based on the total weight of the first network-forming component, of one or more first network initiators capable of initiating the polymerization of the first oligomer and the first network monomer; and
iv. optionally, up to 15 wt % of one or more further first network monomers, oligomers, or polymers having a number average of 2 or more polymerizable groups that are able to (co)polymerize with the polymerizable groups of the first oligomer or the one or more first-network monomers;
b. a second network-forming component comprising one or more second network compounds comprising polymerizable groups that do not (co)polymerize with the polymerizable groups of the first oligomer, and a second network initiator for initiating the polymerization of the one or more second network compounds; and
c. optionally, a particulate filler comprising a polymerizable group that is able to (co)polymerize with the polymerizable groups of the first oligomer.
2. The composition of claim 1 , wherein the first network initiator comprises a photo-initiator.
3. The composition of claim 1 , wherein a film formed by polymerizing 90% or more of total the polymerizable groups in the composition has a tensile modulus measured at 150° C. of from 3 and 50 MPa and a Tg of 40° C. or higher.
4. The composition of claim 1 , wherein the polymerizable groups of the first oligomer comprise endgroups.
5. The composition of claim 4 , wherein the polymerizable groups of the first oligomer consist of endgroups.
6. The composition of claim 4 , wherein the first oligomer has a number average of from 2 to 3 endgroups, and wherein the amount, number average molecular weight, and number average of endgroups of the first oligomer in the composition satisfies the following equation:
XMPa
≤
3
*
R
*
T
*
[
(
3
-
f
)
*
(
ρ
*
w
oligomer
M
oligomer
)
+
(
f
-
2
)
*
3
*
(
ρ
*
w
oligomer
M
oligomer
)
]
≤
YMPa
wherein R is the gas constant 8.314 cm 3 MPa K −1 mol −1 , is 423.15 K, f is the number average of endgroups of the first oligomer, p is the density of the first oligomer in g/cm 3 , M oligomer is the number average molecular weight of the first oligomer in g/mol, W oligomer is the weight fraction of the first oligomer in the first network-forming component, X is 3, and Y is 50.
7. The composition of claim 1 , wherein at least 50 mol % of the backbone of the first oligomer comprises a polyepoxide based on Bisphenol A, F, or S, a polyepoxide based on hydrogenated Bisphenol A, F, or S, a polycarbonate, or a polyimide.
8. The composition of claim 7 , wherein the backbone of the first oligomer comprises a Bisphenol A polycarbonate.
9. The composition of claim 7 , wherein the first oligomer has a number average of from 2 to 3 endgroups.
10. The composition of claim 7 , wherein the first oligomer has a number average molecular weight of from 800 to 8000 g/mol.
11. The composition of claim 4 , wherein a linear polymer formed from the one or more first network monomers has a Tg of 60° C. or more.
12. The composition of claim 10 , wherein the one or more first network monomers have a number average molecular weight of 300 g/mol or less.
13. The composition of claim 12 , wherein the one or more first network monomers comprises methyl (meth)acrylate, hydroxy ethyl (meth)acrylate, hydroxy propyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, or isobutyl (meth)acrylate.
14. An article formed by polymerizing the composition of claim 1 , wherein a film formed by polymerizing 90% or more of total the polymerizable groups in the composition has a tensile modulus as measured at 150° C. of from 3 MPa to 50 MPa, as determined by DMTA in accordance with ASTM D5026.
15. A method of forming a three-dimensional object comprising the steps of:
a. forming a layer of the composition according to claim 1 ,
b. curing the layer with electromagnetic radiation in order to form a desired shape, and
c. repeating the steps of forming and curing a plurality of times to obtain a three-dimensional object.