(meth)acrylate-functional radiation curable compositions for additive fabrication
Described herein are thermoset compositions and kits of compositions suitable for use in additive fabrication processes including specified concentrations of reactive compounds including urethane-(meth)acrylate compounds, monofunctional diluent monomers, and methacrylate-functional compounds having 1.5 polymerizable groups or more. Also described and claimed are methods of creating three-dimensional parts via additive fabrication processes utilizing the compositions elsewhere herein described and claimed, as well as the articles cured therefrom.
1 . A radiation curable composition for additive fabrication comprising, relative to the entire weight of the composition:
from 40 to 95 wt. %, based on the total weight of the composition, of a (i) urethane (meth)acrylate oligomer having at least one polymerizable group,
wherein the urethane (meth)acrylate oligomer is the reaction product of a diisocyanate, a polyether polyol, and a hydroxy-functional (meth)acrylate;
from 0 to less than 40 wt. % of (ii) a monofunctional reactive diluent monomer;
greater than 20 wt. % of (iii) one or more methacrylate-functional compounds comprising a number average of greater than 1.5 polymerizable groups;
wherein at least one of the polymerizable groups of the compound according to (iii) is (co)polymerizable with the at least one polymerizable group of the oligomer according to (i) and/or (ii); and
wherein the compound according to (iii) possesses a number average molecular weight (Mn) value that is less than the Mn value of the oligomer according to (i) and greater than the Mn of the monomer according to (ii);
wherein Mn is measured by size exclusion chromatography (SEC) method.
2 . The radiation curable composition according to claim 1 , further comprising, relative to the weight of the entire composition,
from 0.5 to 8 wt. % of one or more photoinitiators; and/or
from 1 to 40 wt. % of one or more additives; wherein the additives further comprise fillers and/or impact modifiers.
3 . The radiation curable composition according to claim 1 , wherein the urethane (meth)acrylate oligomer (i) possess an Mn value from 750 to 10000 g/mol; and/or
wherein the compound(s) according to (iii) possess an Mn value of less than 750 g/mol and a number average from 1.9 to 3.1, or from 1.9 to 2.1 polymerizable groups.
4 . The radiation curable composition according to claim 1 , wherein the oligomer(s) according to (i) possesses an uncured Tg, as measured by differential scanning calorimetry, from −50 to 10° C.; and/or wherein the oligomer(s) according to (i) possess a number average from 0.9 to 2.1, or from 1.9 to 2.1 polymerizable groups.
5 . The radiation curable composition according to claim 1 , wherein the oligomer(s) according to (i) are present by weight, relative to the entire composition, from 50 to 95 wt. %.
6 . The radiation curable composition according to claim 1 , wherein the oligomer(s) according to (i) comprises the reaction product of isophorone diisocyanate, hexane diisocyanate, 2,2,4-trimethyl hexane diisocyanate, 2,4,4-trimethylhexane diisocyanate, pentane diisocyanate or 4,4-methylene bis(cyclohexyl isocyanate), or mixtures thereof;
and/or
wherein the oligomer(s) according to (i) comprise the reaction product of a polyol having an Mn from 200 to 6000 g/mol, wherein the polyol comprises polyethylene glycol, polypropylene glycol, poly THF, polybutylene oxide, polyethylene co-propylene oxide, or polyethylene oxide-block-propylene oxide, or mixtures thereof.
7 . The radiation curable composition according to claim 1 , wherein the oligomer(s) according to (i) comprise the reaction product of hydroxy ethyl methacrylate, 1-hydroxypropyl methacrylate, 2-hydroxypropyl methacrylate, 1-hydroxybutyl methacrylate, diethylene glycol methacrylate, dipropylene glycol methacrylate, or caprolactone 2-(methacryloyloxy) ethyl ester, or mixtures thereof.
8 . The radiation curable composition according to claim 1 , wherein the polymerizable groups comprises acrylate groups.
9 . The radiation curable composition according to claim 1 , wherein the compound(s) according to (ii) comprises monofunctional urethane methacrylates.
10 . The radiation curable composition according to claim 1 , wherein the compound(s) according to (ii) comprises isopropylideneglycerol methacrylate (IPGMA), (hydroxyethyl) methacrylate (HEMA), 2-hydroxypropyl methacrylate (HPMA), benzyl methacrylate (BMA), cyclohexyl methacrylate, isobornyl methacrylate, or 4-tbutylcyclohexyl methacrylate, THFmethacrylate, phenyl methacrylate, 2,2,4-trmethylcyclohexyl methacrylate, or mixtures thereof.
11 . The radiation curable composition according to claim 10 , wherein the compound(s) according to (iii) comprises bisphenol A glycidyl methacrylate, a triethylene glycol dimethacrylate, a trimethylhexamethylene diisocyanate di(hydroxyethyl) methacrylate, or a methacrylate-terminated isocyanate comprising a methacrylate-terminated moiety and an isocyanate moiety, or mixtures thereof.
12 . The radiation curable composition according to claim 1 , wherein the compound(s) according to (iii) comprises difunctional compounds having a number average molecular weight from 150 to 750 g/mol; and/or
wherein the compound(s) according to (iii) are present, relative to the weight of the entire composition, from 15 to 55 wt. %.
13 . The radiation curable composition according to claim 1 , wherein the polymerizable groups in the compound(s) according to (i) consist of acrylate groups, and wherein the polymerizable groups in the compound(s) according to (iii) consist of methacrylate groups.
14 . The radiation curable composition according to claim 1 , wherein the composition contains from 0 to 0.1 equivalents of acrylate groups; and/or
from 0.2 to 0.3 equivalents of methacrylate groups.
15 . The method according to claim 1 , wherein a linear polymer formed from the oligomer(s) according to (i) has a Tg between-80 to 20° C.