# US 11,440,994 B2 · Dual-cure method and system for fabrication of 3D polymeric structures

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- Number: US 11,440,994 B2
- Document ID: US11440994B2
- Status: Granted
- Kind: B2
- Application number: 16/732,178
- Filed: 2019-12-31
- Published: 2020-09-03
- Granted: 2022-09-13
- Earliest claimed: 2018-12-31
- Assignees: Zhejiang Xunshi Technology Co. Ltd
- Applicants: Zhejiang Xunshi Technology Co., Ltd.
- Inventors: Hailun Borjigin; Lingzhu Zhang
- Web page: https://patentgrep.com/patent/US11440994B2

## CPC

- C08G 73/1025: {polymerised by radiations}
- B29C 64/106: using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
- B29C 64/129: characterised by the energy source therefor, e.g. by global irradiation combined with a mask
- B29C 64/393: for controlling or regulating additive manufacturing processes
- C08F 8/14: Esterification
- C08F 8/32: by reaction with amines
- C08F 290/042: {Polymers of hydrocarbons as defined in group C08F10/00}
- C08F 290/062: {Polyethers}
- C08G 73/1028: {characterised by the process itself, e.g. steps, continuous}
- C08G 73/105: {with oxygen only in the diamino moiety}
- C08G 73/1082: {wholly aromatic in the tetracarboxylic moiety}
- C09D 11/101: Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
- B29K 2079/08: {PI, i.e. polyimides or derivatives thereof}
- B33Y 10/00: Processes of additive manufacturing
- B33Y 50/02: for controlling or regulating additive manufacturing processes
- B33Y 70/00: Materials specially adapted for additive manufacturing
- C08F 2810/30: leading to the formation or introduction of aliphatic or alicyclic unsaturated groups
- C08F 2810/40: taking place solely at one end or both ends of the polymer backbone, i.e. not in the side or lateral chains
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING

## Abstract

A dual-cure method for forming a solid polymeric structure is provided. An end-capped, imide-terminated prepolymer is combined with at least one photopolymerizable olefinic monomer, at least one photoinitiator, and a diamine, to form a curable resin composition, which, in a first step, is irradiated under conditions effective to polymerize the at least one olefinic monomer, thus forming a scaffold composed of the prepolymer and the polyolefin with the diamine trapped therein. The irradiated composition is then thermally treated at a temperature effective to cause a transimidization reaction to occur between the prepolymer and the diamine, thereby releasing the end caps of the prepolymer and providing the solid polymeric structure. A curable resin composition comprising an end-capped, imide-terminated prepolymer, at least one photopolymerizable olefinic monomer, at least one photoinitiator, and a diamine, is also provided, as are related methods of use.

## Claims

### Claim 1

In a method for forming a three-dimensional object using an additive fabrication process that comprises computer-controlled successive formation of layers on a substrate with dimensions corresponding to a 3D digital image, the improvement which comprises forming the layers by:
(a) providing an initial curable layer on a substrate, wherein the layer comprises a curable resin composition prepared by combining an end-capped, imide-terminated prepolymer, a photopolymerizable olefinic monomer, at least one photoinitiator, and a diamine;
(b) irradiating the initial layer under conditions effective to polymerize the olefinic monomer and provide a polyolefin within a first scaffold layer comprising the prepolymer and the polyolefin with the diamine physically trapped therein;
(c) repeating step (a) to provide an additional layer on the first scaffold layer;
(d) irradiating the additional layer under conditions effective to polymerize the olefinic monomer and provide an additional scaffold layer;
(e) repeating steps (c) and (d) until formation of the 3D object is complete; and
(f) thermally treating the 3D object at a temperature effective to cause a transimidization reaction to occur between the prepolymer and the diamine
wherein the prepolymer has the structure of Formula (I)
wherein:
L comprises an oligomeric hydrocarbylene moiety that is unsubstituted, substituted, heteroatom-containing, or substituted and heteroatom-containing;
Ar is aryl;
R1 and R3 may be the same or different and are non-oligomeric linking groups;
q and r may be the same or different and are zero or 1; and
R2 and R4 are imide end-capping groups that can be removed in a transimidization reaction;
wherein L comprises a poly(ethylene oxide) chain or a polyethylene chain.

### Claim 2 (depends on 1)

The method of claim 1, wherein L is unsubstituted.

### Claim 3 (depends on 2)

The method of claim 2, wherein Ar is monocyclic.

### Claim 4 (depends on 3)

The method of claim 3 wherein Ar does not contain heteroatoms.

### Claim 5 (depends on 4)

The method of claim 4, wherein Ar is phenyl, such that the prepolymer has the structure of Formula (II)

### Claim 6 (depends on 5)

The method of claim 5, wherein r and q are 1.

### Claim 7 (depends on 6)

The method of claim 6, wherein R1 and R3 are the same, and R2 and R4 are the same.

### Claim 8 (depends on 7)

The method of claim 7, wherein R1 and R3 comprise phthalimide groups, such that the prepolymer has the structure of Formula (III)
wherein s and t are independently zero or 1, and X and Y are selected from O, S, and lower alkylene.

### Claim 9 (depends on 8)

The method of claim 8, wherein s and t are zero, such that the prepolymer has the structure of Formula (IV)

### Claim 10 (depends on 9)

The method of claim 9, wherein L is polyethylene, such that the prepolymer has the structure of Formula (V)
where n is the number of oxyethylene monomer units in L.

### Claim 11 (depends on 10)

The method of claim 10, wherein R2 and R4 are both 2-pyrimidinyl, such that the prepolymer has the structure of Formula (X)

### Claim 12 (depends on 9)

The method of claim 9, wherein L is polyethylene, such that the prepolymer has the structure of Formula (VI)
wherein n is the number of ethylene monomer units in L.

### Claim 13 (depends on 12)

The method of claim 12, wherein R2 and R4 are both 2-pyrimidinyl, such that the prepolymer has the structure of Formula (XI)

### Claim 14 (depends on 8)

The method of claim 8, wherein s and t are 1 and X and Y are both O, such that the prepolymer has the structure of Formula (VII)

### Claim 15 (depends on 14)

The method of claim 14, wherein L is poly(ethylene oxide), such that the prepolymer has the structure of Formula (VIII)
where n is the number of oxyethylene monomer units in L.

### Claim 16 (depends on 15)

The method of claim 15, wherein R2 and R4 are both 2-pyrimidinyl.

### Claim 17 (depends on 14)

The method of claim 14, wherein L is poly(ethylene), such that the prepolymer has the structure of Formula (IX)
where n is the number of ethylene monomer units in L.

### Claim 18 (depends on 17)

The method of claim 17, wherein R2 and R4 are both 2-pyrimidinyl.

### Claim 19 (depends on 1)

The method of claim 1, wherein the prepolymer has a weight average molecular weight in the range of about 500 to about 5000.

### Claim 20 (depends on 19)

The method of claim 19, wherein the prepolymer has a weight average molecular weight in the range of about 1000 to about 3000.

### Claim 21 (depends on 1)

The method of claim 1, wherein the polymerizable olefinic monomer is an acrylate or methacrylate monomer.

### Claim 22 (depends on 21)

The method of claim 21, wherein the acrylate or methacrylate monomer has the structure of Formula (XIV)
wherein R5 is H or CH3 and R6 is C1 to C36 hydrocarbyl, substituted C1 to C36 hydrocarbyl, heteroatom-containing C1 to C36 hydrocarbyl, or substituted and heteroatom-containing C1 to C36 hydrocarbyl.

### Claim 23 (depends on 22)

The method of claim 22, wherein R6 comprises a C6-C36 alicyclic moiety.

### Claim 24 (depends on 23)

The method of claim 23, wherein R6 is isobornyl.

### Claim 25 (depends on 1)

The method of claim 1, wherein the diamine has the structure of Formula (XV)
H2N-L1-NH2 (XV)
where L1 is C2 to C14 hydrocarbylene, substituted C2 to C14 hydrocarbylene, heteroatom-containing C2 to C14 hydrocarbylene, or substituted and heteroatom-containing C2 to C14 hydrocarbylene.

### Claim 26 (depends on 25)

The method of claim 25, wherein L1 is unsubstituted C2 to C14 alkylene.

### Claim 27 (depends on 1)

The method of claim 1, wherein the irradiating is carried out using actinic radiation.

### Claim 28 (depends on 27)

The method of claim 27, wherein the actinic radiation is ultraviolet radiation having a wavelength selected to facilitate polymerization of the photopolymerizable olefinic monomer.

### Claim 29 (depends on 28)

The method of claim 28, wherein the wavelength is about 405 nm.

### Claim 30 (depends on 1)

The method of claim 1, wherein the thermal treatment is carried out at a temperature in the range of about 75° C. to about 300° C.