Thermosetting compositions and forming three-dimensionalobjects 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 TPA-based polyester 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 TPA-based polyester comprises the reaction product of a terephthalic acid and a polyol. 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 TPA-based polyester comprising a backbone and having a number average of at least 2 polymerizable groups, wherein the backbone comprises the reaction product of one or more polyacids including a terephthalic acid and a polyol, wherein the polymerizable groups comprise acrylate, methacrylate, epoxy, oxetane, hydroxyl, itaconate, vinyl ether, allyl ether, maleate, or fumarate, and wherein the TPA-based polyester has a number average molecular weight of from 800 to 10000 g/mol and a Tg of at least 25° C.;
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 TPA-based polyester, wherein a linear polymer formed from the one or more first network monomers has a Tg of at least 25° C.; and
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 TPA-based polyester and the first network monomer; and
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 TPA-based polyester, and a second network initiator for initiating the polymerization of the one or more second network compounds.
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 according to claim 1 , wherein the polymerizable groups comprise endgroups.
5. The composition according to claim 4 , wherein the polymerizable groups consist of endgroups.
6. The composition of claim 4 , wherein the TPA-based polyester 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 TPA-based polyester in the composition satisfies the following equation:
XMPa
≤
3
*
R
*
T
*
[
(
3
-
f
)
*
(
ρ
*
w
polyester
M
polyester
)
+
(
f
-
2
)
*
3
*
(
ρ
*
w
polyester
M
polyester
)
]
≤
YMPa
wherein R is the gas constant 8.314 cm 3 MPa K −1 mol −1 , T is 423.15 K, f is the number average of endgroups of the TPA-based polyester, p is the density of the TPA-based polyester in g/cm 3 , M polyester is the number average molecular weight of the TPA-based polyester in g/mol, w polyester is the weight fraction of the TPA-based polyester 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 one or more polyacids consists of the terephthalic acid.
8. The composition of claim 1 , wherein at least 75 mol % of the one or more polyacids consists of the terephthalic acid.
9. The composition of claim 1 , wherein the TPA-based polyester has a number average of from 2 to 3 endgroups.
10. The composition of claim 1 , wherein the TPA-based polyester 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 1 , wherein the one or more first network monomers have a molecular weight of 300 g/mol or less.
13. The composition of claim 1 , 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. The composition of claim 1 , wherein the one or more first network monomers comprises cyclohexene oxide, tert-butyl glycidyl ether, 4-chlorophenyl glycidyl ether, cyclopentene oxide, exo-2,3-Epoxynorbornane, 1,2-Epoxy-3-phenoxypropane, (2,3-Epoxypropyl)benzene, N-(2,3-Epoxypropyl)phthalimide, exo-3,6-Epoxy-1,2,3,6-tetrahydrophthalic anhydride, 3,4-Epoxytetrahydrothiophene-1,1-dioxide, Furfuryl glycidyl ether, glycidyl 4-methoxyphenyl ether, glycidyl 2-methylphenyl ether, isophorone oxide, a-Pinene oxide, cis-stilbene oxide, styrene oxide, Methyl,Methyl 7-oxabicyclo[4.1.0]heptane-3-carboxylate, 22-Ethylhexyl 7-oxabicyclo(4.1.0)heptane-3-carboxylate, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3-(3-hydroxypropyl)oxymethyloxetane, or 3-ethyl-3-(4-hydroxybutyl)oxymethyloxetane.
15. A method of forming a three-dimensional object comprising:
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.