Cyanate ester dual cure resins for additive manufacturing

Patent metadata

Field	Value
Publication number	US-11040483-B2
Application number	US-201916576844-A
Country	US
Kind code	B2
Filing date	Sep 20, 2019
Priority date	Sep 4, 2015
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A method of forming a three-dimensional object is carried out by: (a) providing a cyanate ester dual cure resin; (b) forming a three-dimensional intermediate from said resin, where said intermediate has the shape of, or a shape to be imparted to, said three-dimensional object, and where said resin is solidified by exposure to light; (c) optionally washing the three-dimensional intermediate, and then (d) heating and/or microwave irradiating said three-dimensional intermediate sufficiently to further cure said resin and form said three-dimensional object. Compositions useful for carrying out the method, and products made from the method, are also described.

First claim

We claim:

1. A method of forming a three-dimensional object, comprising:
(a) providing a cyanate ester dual cure resin;
(b) forming, by additive manufacturing, a three-dimensional intermediate from said resin, where said intermediate has the shape of, or a shape to be imparted to, said three-dimensional object, and wherein said resin is solidified by exposure to light;
(c) optionally washing the three-dimensional intermediate, and then
(d) heating and/or microwave irradiating said three-dimensional intermediate sufficiently to further cure said resin and form said three-dimensional object;
wherein said cyanate ester dual cure resin comprises:
(i) a photoinitiator;
(ii) monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light;
(iii) optionally, a light absorbing pigment or dye;
(iv) a metal catalyst;
(v) at least one cyanate ester compound, and/or a prepolymer thereof, each said cyanate ester compound independently having a structure of Formula I:
R O—C≡N) m   (I)

wherein m is 2, 3, 4, or 5, and R is an aromatic or aliphatic group; and
(vi) optionally a filler.

2. The method of claim 1 , wherein R is a phenyl group.

3. The method of claim 1 , wherein R is a phenyl, biphenyl, naphthyl, bis(phenyl)methane, bis(phenyl)ethane, bis(phenyl)propane, or bis(phenyl)dicyclopentadiene group, or a phenol formaldehyde resin.

4. The method of claim 1 , wherein said cyanate ester compound is selected from the group consisting of: bis(4-cyanathophenyl) methane; 1,1-bis(4-cyanatophenyl)ethane; 2,2-bis(4-cyanatophenyl) propane; bis(4-cyanatophenyl)ether; tetramethyl-1,4-dicyanatobenzene; cyanated novolacs produced by reacting a novolac with cyanogen halide; cyanated bisphenol polycarbonate oligomers produced by reacting a bisphenol polycarbonate oligomer with cyanogen halide; and mixtures thereof.

5. The method of claim 1 , wherein said metal catalyst is a chelate or oxide of a metal selected from the group consisting of divalent, zinc, tin, and cobalt, and trivalent cobalt, manganese and aluminum.

6. The method of claim 1 , wherein said metal catalyst is present in a range of 10 to 1,000 microequivalents of said metal catalyst as compared to the total weight of said at least one cyanate ester or prepolymer thereof.

7. The method of claim 1 , wherein said monomers and/or prepolymers polymerizable by exposure to actinic radiation or light comprise reactive end groups selected from the group consisting of acrylates, methacrylates, α-olefins, N-vinyls, acrylamides, and methacrylamides.

8. The method of claim 1 , wherein said light absorbing pigment or dye is:
(i) titanium dioxide,
(ii) carbon black, and/or
(iii) an organic ultraviolet light absorber.

9. The method of claim 1 , wherein said resin comprises at least one cyanate ester prepolymer.

10. The method of claim 9 , wherein said cyanate ester prepolymer comprises the reaction product of cyanate ester monomers, has a molecular weight of 200 grams/mole to 8,000 grams/mole, and a degree of conversion of cyanate groups of from 1 to 40 percent.

11. The method of claim 1 , wherein said resin comprises:
(i) from 0.1 to 4 percent by weight of said photoinitiator,
(ii) from 25 to 60 percent by weight of said monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light,
(iii) from 0.1 to 2 percent by weight of said light absorbing pigment or dye when present,
(iv) from 0.001 to 0.1 percent by weight of said metal catalyst;
(v) from 25 to 60 percent by weight of said cyanate ester compound and/or prepolymer thereof; and
(vi) from 1 to 20 percent by weight of said filler when present.

12. The method of claim 1 , wherein said forming step is carried out by bottom-up or top-down three-dimensional fabrication.

13. The method of claim 1 , wherein said forming step is carried out:
(i) by either bottom-up three dimensional fabrication between a carrier and a build surface or top-down three dimensional fabrication between a carrier and a fill level, the fill level optionally defined by a build surface;
(ii) optionally with a stationary build surface;
(iii) optionally while maintaining the resin in liquid contact with both the intermediate object and the build surface; and
(iv) optionally with said forming step carried out in a layerless manner, each during the formation of at least a portion of the three-dimensional intermediate.

14. The method of claim 1 , wherein said heating step is carried out at at least a first temperature and a second temperature,
with said first temperature greater than ambient temperature, said second temperature greater than said first temperature, and said second temperature less than 300° C.

15. The method of claim 1 , said resin further comprising a stabilizer, such as an acid having a pKa of 2 or less, included in said composition in an amount of from 0.001 or 0.01 percent by weight to 0.5 or 1 percent by weight.

Assignees

• Carbon Inc

Inventors

• Menyo Matthew S
• Rolland Jason P

Classifications

• B33Y70/10

  Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials · CPC title

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title

• B29C64/124 Primary

  using layers of liquid which are selectively solidified · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• C08G73/065 Primary

  Preparatory processes · CPC title