# US 11,028,205 B2 · Water-breakable formulations and additive manufacturing processes employing same

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- Number: US 11,028,205 B2
- Document ID: US11028205B2
- Status: Granted
- Kind: B2
- Application number: 16/070,280
- Filed: 2017-01-15
- Published: 2019-01-10
- Granted: 2021-06-08
- Earliest claimed: 2016-01-15
- Assignees: Stratasys, Inc.
- Applicants: Stratasys Ltd.
- Inventors: Tal Ely; Mariana Pokrass; Dani Peri; Avraham Levy; Dana Tenne
- Web page: https://patentgrep.com/patent/US11028205B2

## CPC

- B29C 64/40: Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
- B29C 64/112: using individual droplets, e.g. from jetting heads
- B33Y 40/10: Pre-treatment
- B33Y 40/20: Post-treatment, e.g. curing, coating or polishing
- B33Y 70/00: Materials specially adapted for additive manufacturing
- G03F 7/0037: {Production of three-dimensional images}
- G03F 7/027: Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds (G03F7/075 takes precedence)
- G03F 7/038: Macromolecular compounds which are rendered insoluble or differentially wettable (G03F7/075 takes precedence; macromolecular azides G03F7/012; macromolecular diazonium compounds G03F7/021)
- B29K 2033/08: {Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate}
- B33Y 10/00: Processes of additive manufacturing
- 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)
- 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
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- 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

## Abstract

Curable formulations which form cured materials that are breakable upon immersion in water are disclosed. The cured materials break into a plurality of particles being a few millimeters or less in size. Methods of fabricating three-dimensional objects utilizing the curable formulations are also disclosed, as well as model objects fabricated thereby. The curable formulations include at least a mono-functional curable material and a multi-functional curable material, as described in the specification.

## Claims

### Claim 1

A curable formulation comprising at least one mono-functional curable material and at least one multi-functional curable material, said mono-functional and multi-functional curable materials and a concentration ratio thereof being selected such that a cured material formed upon exposing the formulation to a curing energy breaks into particles upon immersion in an aqueous solution,
wherein:
said cured material breaks upon said immersion into particles having a size ranging from 1 micron to 100 mm; and/or
said cured material features a degree of cross linking that ranges from 10 to 80%; and/or
said cured material has a swelling capacity of from 10 to 300% by weight; and/or
a 3-gram cube made of said cured material breaks upon static immersion in water in less than 10 hours.

### Claim 2 (depends on 1)

The curable formulation of claim 1, wherein said at least one mono-functional curable material is represented by Formula I:
wherein:
Ra is hydrogen, alkyl or cycloalkyl; and
Z is represented by X-L-Y,
wherein:
X is selected from C(═O), C(═O)—NR1, C(═O)—O, P(═O)—(OR2)—O or is absent;
Y is selected from O−M+, OR3, NR4R5 or N+R4R5R6Q;
L is a hydrocarbon moiety of 1 to 40 atoms in length, optionally interrupted by one or more heteroatom(s), said heteroatoms being independently selected from O, S and NR2, or is absent;
Q is a negatively charged counter ion;
M+is a positively charged counter ion;
R1 and R2 are each independently selected from hydrogen, alkyl and cycloalkyl;
R3 is selected from hydrogen, alkyl, cycloalkyl and aryl; and
R4, R5 and R6 are each independently selected from hydrogen, alkyl and cycloalkyl, or, alternatively, R4 and R5 form a cyclic ring.

### Claim 3 (depends on 2)

The curable formulation of claim 2, wherein Y is N+R4R5R6Q.

### Claim 4 (depends on 3)

The curable formulation of claim 3, wherein L is a hydrocarbon moiety of 1 to 4 carbon atoms in length.

### Claim 5 (depends on 2)

The curable formulation of claim 2, wherein Y is NR4R5.

### Claim 6 (depends on 2)

The curable formulation of claim 2, wherein Y is OR3.

### Claim 7 (depends on 6)

The curable formulation of claim 6, wherein L is a hydrocarbon moiety interrupted by one or more heteroatom(s).

### Claim 8 (depends on 1)

The curable formulation of claim 1, wherein said mono-functional curable material forms a polymeric (cured) material featuring:
a water uptake of at least 200%; and/or
a hydrophilic lipophilic balance, determined according to Davies method, of at least 10; and/or
a water solubility of at least 50 weight percents.

### Claim 9 (depends on 1)

The curable formulation of claim 1, wherein said at least one multi-functional curable material:
(i) forms a polymer featuring a Tg higher than 20° C.; and/or
(iii) is represented by Formula II:
wherein:
Rb is hydrogen, alkyl or cycloalkyl;
n is an integer of from 2 to 10, representing a number of polymerizable groups ═C(Rb)—W—;
W in each of said polymerizable groups is independently selected from C(═O)—O, C(═O)—NR8, and C(═O) or is absent; and
B is a hydrocarbon moiety of 1 to 20 atoms, interrupted and/or substituted by at least one hydrogen donor-containing group.

### Claim 10 (depends on 9)

The curable formulation of claim 9, wherein said multi-functional curable material forms a polymer featuring said Tg higher than 20° C..

### Claim 11 (depends on 10)

The curable formulation of claim 10, wherein said multi-functional curable material is represented by Formula II.

### Claim 12 (depends on 11)

The curable formulation of claim 11, wherein said hydrogen donor-containing group is selected from oxygen, hydroxy, hydroxyalkyl, amine, aminoalkyl, thiol, and thioalkyl.

### Claim 13 (depends on 1)

The curable formulation of claim 1, wherein a concentration of said at least one mono-functional curable material ranges from 40 to 90, weight percents of the total weight of the formulation.

### Claim 14 (depends on 1)

The curable formulation of claim 1, wherein a concentration of said multi-functional curable material ranges from 5 to 60 weight percents of the total weight of the formulation.

### Claim 15 (depends on 1)

The curable formulation of claim 1, further comprising at least one non-curable material.

### Claim 16 (depends on 15)

The curable formulation of claim 15, wherein said at least one non-curable material comprises a water-miscible polymer.

### Claim 17 (depends on 1)

The curable formulation of claim 1, wherein at least 50% of said particles have a size lower than 10 mm.

### Claim 18 (depends on 1)

A method of fabricating a three-dimensional model object, the method comprising dispensing a building material so as to sequentially form a plurality of layers in a configured pattern corresponding to the shape of the object, wherein said building material comprises the curable formulation of claim 1.

### Claim 19 (depends on 18)

The method of claim 18, wherein said building material comprises a modeling material formulation and a support material formulation, said support material formulation comprising said curable formulation.

### Claim 20 (depends on 19)

The method of claim 19, further comprising, subsequent to said dispensing, exposing the building material to curing energy, to thereby obtain a printed objected which comprises a cured support material formed of said curable formulation; and
removing said cured support material, to thereby obtain the three-dimensional model object,
said removing comprises contacting said cured support material with water.

### Claim 21 (depends on 20)

The method of claim 20, wherein said contacting comprises static immersion of said cured support material in said water.

### Claim 22 (depends on 18)

A three-dimensional object fabricated by the method of claim 18.