Conductive photo-curable compositions for additive manufacturing
A photo-curable composition for use in additive manufacturing, said composition comprising: a) at least one photocurable monomer or oligomer; b) a photoinitiator for polymerization of the monomer; and, from 0.01 to 1 wt. %, based on the weight of the composition, of c) CNS-derived materials. Following polymerization, the resulting polymerized composition has a volume resistivity no greater than 10 5 ohm·cm.
1. A photo-curable composition for use in additive manufacturing, said composition comprising:
a) at least one photocurable monomer or oligomer;
b) a photoinitiator for polymerization of the monomer or oligomer; and,
from 0.01 to 2 wt. %, based on the weight of the composition, of c) at least one CNS-derived material selected from the group consisting of: carbon nanostructures, fragments of carbon nanostructures, fractured carbon nanotubes, elongated CNS strands, dispersed CNSs, and any combination thereof, wherein,
following polymerization, the resulting polymerized composition has a resistivity, as measured by CTM Method 1, no greater than 10 5 ohm·cm,
the carbon nanostructures or fragments of carbon nanostructures include a plurality of multiwall carbon nanotubes that are crosslinked in a polymeric structure by being branched, interdigitated, entangled and/or sharing common walls,
the fractured carbon nanotubes are derived from the carbon nanostructures and are branched and share common walls with one another, and
elongated CNS strands are derived from the carbon nanostructures and include CNTs that have been displaced linearly with respect to one another, and
the dispersed CNS comprise exfoliated fractured CNTs that do not share common walls with one another.
2. The composition according to claim 1 comprising, based on the weight of the composition, from 5 to 95 wt. % of said at least one photocurable monomer or oligomer.
3. The composition according to claim 1 , wherein said component a) comprises a cationically curable monomer or oligomer, a radically curable monomer or oligomer, or a mixture thereof.
4. The composition according to claim 1 , wherein said component a) is characterized by comprising:
a1) one or more (meth) acrylate functionalized oligomers; and,
a2) one or more (meth)acrylate monomers, said monomers being selected from the group consisting of monofunctional (meth)acrylate monomers and difunctional (meth)acrylate monomers.
5. The composition according to claim 4 , wherein the macro-monomer component a1) comprises or consists of one or more oligomers selected from the group consisting of epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates and polyether (meth)acrylates.
6. The composition according to claim 5 , wherein the (meth)acrylate monomers a2) comprise esters of C 1 -C 4 monofunctional alcohols with (meth)acrylic acid.
7. The composition according to claim 1 , wherein said component a) comprises an organopolysiloxane monomer, oligomer, or mixture thereof.
8. The composition according to claim 1 comprising, based on the weight of the composition, from 0.1 to 10 wt. % of photoinitiator b).
9. The composition according to claim 1 comprising, based on the weight of the composition, from 0.01 to 1.5 wt. % of said CNS-derived material.
10. The composition according to claim 1 , wherein the carbon nanostructures are coated or in a mixture with a binder.
11. The composition according to claim 10 , wherein the weight of the binder relative to the weight of the coated carbon nanostructures is within the range of from about 0.1% to about 10%.
12. The composition according to claim 1 , further comprising one or more additives selected from fillers, solvents, reactive diluents, corrosion inhibitors, catalysts, antioxidants, UV absorbers/light stabilizers, hydrolysis stabilizers, metal deactivators, antistatic agents, reinforcers, antifogging agents, propellants, biocides, plasticizers, lubricants, emulsifiers, dyes, pigments, rheological agents, impact modifiers, adhesion regulators, optical brighteners, flame retardants, anti-drip agents, nucleating agents, wetting agents, thickeners, protective colloids, defoamers, and tackifiers.
13. The composition according to claim 1 , further comprising one or more additives selected from plasticizers, antioxidants, UV stabilizers, hydrolysis stabilizers, toughening rubbers, and fillers.
14. The photo-curable composition according to claim 1 comprising, based on the weight of the composition:
from 5 to 20 wt. % of a1) one or more (meth)acrylate functionalized oligomers selected from the group consisting of epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates and polyether (meth)acrylates;
from 20 to 80 wt. % of a2) one or more (meth)acrylate monomers, said monomers being selected from the group consisting of monofunctional (meth)acrylate monomers and difunctional (meth)acrylate monomers;
from 0.1 to 10 wt. % of b) photoinitiator; and,
from 0.01 to 2 wt. % of c) said at least one CNS-derived material.
15. The photo-curable composition according to claim 1 comprising, based on the weight of the composition:
from 5 to 15 wt. % of a1) one or more (meth)acrylate functionalized oligomers selected from the group consisting of epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates and polyether (meth)acrylates;
from 40 to 80 wt. % of a2) one or more (meth)acrylate monomers, said monomers being selected from the group consisting of monofunctional (meth)acrylate monomers and difunctional (meth)acrylate monomers;
from 0.1 to 5 wt. % of b) photoinitiator; and
from 0.01 to 2 wt. % of c) said at least one CNS-derived material.
16. A method for forming a three dimensional object, said method comprising:
i) providing a carrier and an optically transparent member having a movable build surface, said carrier and build surface defining a build region there between;
ii) within said build region, applying by 3D printing a first layer of the composition as defined in claim 1 ;
iii) irradiating said build region through said optically transparent member to at least partially cure that first layer;
iv) applying a subsequent layer of said composition by 3D printing on the at least partially cured layer; and,
v) irradiating said build region through said optically transparent member to at least partially cure that subsequent layer.
17. An iterative method according to claim 16 for forming a three dimensional object, wherein said steps iv) and v) are performed and repeated so as to dispose second, third, fourth and further layers within the build region.