Support material for 3D printing of polymer compounds

Abstract

Cyclic olefin copolymer (COC) and cyclic olefin polymer (COP) are useful as support material for 3D printing of high temperature polymers, such as polyimides.

Claims

1. A scaffold built by a support material during 3D polyimide printing comprising cyclic olefin copolymer or cyclic olefin polymer.

2. The scaffold of claim 1, wherein the cyclic olefin copolymer (COC) is a copolymer of cyclic olefin monomers with alkenes.

3. The scaffold of claim 2, wherein the cyclic olefin copolymer is ethylene-norbornene copolymer.

4. The scaffold of claim 3, wherein the ethylene-norbornene copolymer has the following structure: ##STR00002## wherein X ranges from about 40 wt. % to about 20 wt. % and wherein Y ranges from about 60 wt. % to about 80 wt. %.

5. The scaffold of claim 3, wherein the ethylene-norbornene copolymer has the following structure: ##STR00003## wherein X ranges from about 25 wt. % to about 18 wt. % and wherein Y ranges from about 75 wt. % to about 82 wt. %.

6. The scaffold of claim 3, wherein the cyclic olefin copolymer has a weight average molecular weight (Mw) ranging from about 40,000 to about 130,000, a heat deflection temperature ranging from about 30° C. to about 170° C. at 0.45 MPa (66 psi load).

7. The scaffold of claim 1, wherein the cyclic olefin polymer (COP) are polymers which have undergone ring-opening metathesis polymerization from cyclic monomers followed by hydrogenation, wherein the cyclic monomers comprise norbornene or tetracyclododecene.

8. The scaffold of claim 1, wherein the scaffold further comprises optical brighteners, impact modifiers, process aids, rheology modifiers, thermal and UV stabilizers, fluorescent and non-fluorescent dyes and pigments, radio-opaque tracers, conductive additives (both thermal and electrical), inductive heating additives, non-silicone releases; and combinations of them.

9. The scaffold of claim 1, wherein the scaffold also comprises styrenic block copolymer as an impact modifier for the scaffold.

10. A 3D printed polymer article comprising polyimide as a build material and the support material of claim 1.

11. The 3D printed polymer article of claim 10, wherein the support material further comprises optical brighteners, impact modifiers, process aids, rheology modifiers, thermal and UV stabilizers, fluorescent and non-fluorescent dyes and pigments, radio-opaque tracers, conductive additives (both thermal and electrical), inductive heating additives, and non-silicone releases; and combinations of them.

12. The support material of claim 11, wherein the support material also comprises styrenic block copolymer as an impact modifier for the support material.

13. A method of using the support material of claim 1, comprising the steps of 3D printing both polyimide as a build material and the support material of claim 1.

14. The method of claim 13, wherein the support material further comprises optical brighteners, impact modifiers, process aids, rheology modifiers, thermal and UV stabilizers, fluorescent and non-fluorescent dyes and pigments, radio-opaque tracers, conductive additives (both thermal and electrical), inductive heating additives, and non-silicone releases; and combinations of them.

15. The method of claim 14, wherein the support material also comprises styrenic block copolymer as an impact modifier for the support material.

16. A 3D printed polymer article comprising polyimide as a build material and the support material of claim 2.

17. A 3D printed polymer article comprising polyimide as a build material and the support material of claim 3.

18. A 3D printed polymer article comprising polyimide as a build material and the support material of claim 4.

19. The 3D printed polymer article of claim 18, wherein the support material further comprises optical brighteners, impact modifiers, process aids, rheology modifiers, thermal and UV stabilizers, fluorescent and non-fluorescent dyes and pigments, radio-opaque tracers, conductive additives (both thermal and electrical), inductive heating additives, and non-silicone releases; and combinations of them.

20. The support material of claim 18, wherein the support material also comprises styrenic block copolymer as an impact modifier for the support material.

Description

EXAMPLES

(1) Two formulations of support material were prepared. Example 1 was 99 wt. % of TOPAS 6017S COC and 1 wt. % Optical Brightener (Eastobrite™ OB-1 from Eastman Chemical Company). Example 2 was 96 wt. % of TOPAS 6017S COC; 1 wt. % of the same Optical Brightener; and 3 wt. % of Kraton G1651 styrenic block copolymer from Kraton, serving as an impact modifier.

(2) Both Examples were compounded and extruded using a 16 mm twin screw extruder 40:1 L/D Thermo electron, set at 270-280° C. and 300 rpm, and having a torque of 56-65%. The extrudate was pelletized.

(3) Pellets of both Examples were then molded using a 120 T (ton) Van Dorn molding machine with a 1.6 mm flexural test bar mold. The molding conditions were a temperature of 270-280° C. and a screw speed of 100-150 rpm. The injection velocity was 0.5-1.0 in/sec, with a pack and hold pressure of 3.44 MPa (500 psi) for 5-6 sec, a back pressure 0.17-0.34 MPa (25-50 psi), a mold temperature of 150-160° C., and a cool time of 15-20 seconds.

(4) To test Examples 1 and 2 for lack of adhesion with polyetherimide polymer resin (Ultem® 9085 from SABIC), a special test method was used.

(5) Test Method for Determining Polymer/Polymer Lack of Adhesion or “Debonding” after Compression Molding

(6) 1. One previously injection molded 1.6 mm thick ASTM Izod bar of the Example was placed on top of a previously injection molded 1.6 mm thick ASTM Izod bar of Ultem® 9085 polyetherimide inside a 3.2 mm thick “MUD frame” which is the term used for a Master Unit Die mold, e.g. a 3.2 mm thick metal frame with cut-outs for the injection molded ASTM Izod specimens. On either side of the cut-out is solid metal. The MUD frame helped to secure the two bars together surface to surface and minimized “flashing” or movement of molten polymer away from the compressed areas of the bars.

(7) 2. The compression mold was heated to a temperature of 230-235° C.

(8) 3. The MUD frame with the overlapping bars was placed into compression unit; the MUD frame was pre-heated for about 30 seconds.

(9) 4. The compression pressure upon the MUD frame containing the two bars was increased up to about 6.2 MPa (900 psi) and held for two minutes.

(10) 5. The pressure was relieved and the MUD frame removed from the compression press.

(11) 6. After the MUD frame cooled to room temperature, the two bars were removed from the MUD frame.

(12) 7. The two bars were tested for their adhesive strength.

(13) Many times the build and support materials debonded on their own, upon cooling.

(14) Test Results

(15) The test bar of Example 1 had more adhesive strength to the Ultem®9085 test bar than the test bar of Example 2. However, both bars of Examples 1 and 2 were sufficiently debonded from the Ultem® 9085 test bar as to be acceptable as support material for polyetherimide containing resins or compounds as a build material. Of the two, Example 2 was preferred because it had less adhesive strength to the Ultem® 9085 test bar than Example 1.

(16) Also, Example 2 was chosen over Example 1 because it exhibited more ductility when wound onto a ˜7.6 (˜3 inch) spool. Example 1 would tend to break while spooling but could be used as cut strands.

(17) The ductility exhibited by Example 2 was desired for spooling lengths of the support material.

(18) In further experimentation comparing COC with COP, it was noted that TOPAS® COC was preferred over Zeonor® COP because the TOPAS® COC caused less “flash” during the adhesion test.

(19) The invention is not limited to the above embodiments. The claims follow.