Three-Dimensional Printing Material System With Improved Color, Article Performance, and Ease of Use

• US 20080187711A1
• Filed: 01/10/2008
• Published: 08/07/2008
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: Z CORPORATION (A Holdings Corp.)
• Inventors: Bredt, James F., Williams, Derek X., Flynn, Mary, Clark, Nanette, Alam, Amir, Sprauer, Jean
• Granted Patent: US 8,167,999 B2
• Time in Patent Office: Days
• US Class Current: 428/114
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 1/147 Making a dispersion
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/105 by using electric current other than for infrared radiant energy, laser radiation or plasma B22F3/11 takes precedence; by ultrasonic bonding B22F3/115 takes precedence
• CPC Class Codes: B28B 1/001 Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material selective deposition modelling of metallic powder B22F10/00; rapid manufacturing of 3D objects in general and in particular of plastics B29C64/00
• CPC Class Codes: B28B 7/465 Applying setting liquid to dry mixtures
• CPC Class Codes: B29C 64/165 using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber
• CPC Class Codes: B33Y 70/10 Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
• CPC Class Codes: C04B 14/10 Clay sepiolite C04B14/042; grog C04B18/025
• CPC Class Codes: C04B 14/24 porous, e.g. foamed glass
• CPC Class Codes: C04B 14/28 of calcium
• CPC Class Codes: C04B 14/30 Oxides other than silica ferrites C04B14/363
• CPC Class Codes: C04B 14/305 Titanium oxide, e.g. titanates
• CPC Class Codes: C04B 2103/10 Accelerators; Activators
• CPC Class Codes: C04B 2103/40 Surface-active agents, dispersants
• CPC Class Codes: C04B 2103/67 Biocides
• CPC Class Codes: C04B 2111/00181 Mixtures specially adapted for three-dimensional printing (3DP), stereo-lithography or prototyping
• CPC Class Codes: C04B 22/147 Alkali-metal sulfates; Ammonium sulfate
• CPC Class Codes: C04B 24/04 Carboxylic acids; Salts, anhydrides or esters thereof
• CPC Class Codes: C04B 24/06 containing hydroxy groups
• CPC Class Codes: C04B 24/2623 : Polyvinylalcohols; Polyvinylacetates
• CPC Class Codes: C04B 24/38 : Polysaccharides or derivatives thereof C04B24/243 takes precedence
• CPC Class Codes: C04B 28/14 : containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: Y10T 428/24132 : including grain, strips, or filamentary elements in different layers or components parallel

Abstract

A materials system and methods are provided to enable the formation of articles by three dimensional printing. The materials system includes particulate mixtures having a whitening agent and a solid particulate additive comprising an acid, the latter adapted for modifying a cure rate of an infiltrant. The materials system also includes aqueous fluids including optical brightening agents.

Claims

1. A powder adapted for three-dimensional printing, the powder comprising:

a loose, dry, and substantially free-flowing particulate mixture comprising;

a water-soluble adhesive;

plaster;

a plaster accelerator;

a whitening agent having an L* of at least about 90 and a C* of up to about 5.5; and

a solid particulate additive comprising an acid,

wherein (i) the particulate material is adapted for use in three-dimensional printing to form an article comprised of a plurality of layers, the layers including a reaction product of the particulate material and an aqueous fluid that contacts the particulate material during three-dimensional printing, and (ii) the acid has a water solubility selected from a range of about 0-20 g/100 mL of water, a pKa selected from a range about 1 to about 4, and a K_ow selected from a range of -about 0.4 to about 1, and is adapted for modifying a cure rate of an infiltrant to facilitate penetration of the infiltrant into the article, and (iii) the particulate mixture is substantially free of plaster retarders.

2. The powder of claim 1, wherein the substantially dry particulate mixture has a Bredt parameter of at least about 0.10.

3. The material system of claim 1, wherein an internal angle of friction of the particulate material has a value selected from a range of 40°

to 70°

.

4. The powder of claim 1 wherein the particulate mixture comprises about 0.01% to about 5% by weight of the whitening agent.

5. The powder of claim 1, wherein a refractive index of the whitening agent is at least about 1.9.

6. The powder of claim 1 wherein the whitening agent has a solubility in an aqueous solution of 5 wt % glycerol of at least about 5 mg/liter.

7. The powder of claim 1 wherein the whitening agent comprises a second water-soluble adhesive.

8. The powder of claim 1 wherein the whitening agent is selected from the group consisting of a high whiteness starch and a high whiteness starch derivative.

9. The powder of claim 1 wherein the whitening agent is insoluble in an aqueous solution of 5 wt % glycerol.

10. The powder of claim 1 wherein the whitening agent is selected from the group consisting of zinc oxide, titanium dioxide, hollow glass spheres, limestone, a clay, and combinations thereof.

11. The powder of claim 1 wherein the water-soluble adhesive comprises polyvinyl alcohol.

12. The additive of claim 1 where the pKa is about 3 and the K_ow is selected from a range of about −

0.5 to about 0.5.

13. The powder of claim 1 wherein the particulate mixture comprises about 0.01% to about 5% by weight of the solid particulate additive.

14. The powder of claim 1 wherein the solid particulate additive is selected from the group consisting of fumaric acid, tartaric acid, gluconic acids, adipic acid, glucono-delta-lactone (GdL), ethylenediaminetetraacetic acid, succinic acid, a phenolic compound, and combinations thereof.

15. The powder of claim 1, wherein the plaster is selected from the group consisting of plaster of paris, sulphate of lime, hydrated calcium sulphate, dental plaster, CaSO₄·

½

H₂O, CaSO₄·

2H₂O, and combinations thereof.

16. The powder of claim 1, wherein the plaster accelerator is selected from the group consisting of hydrated gypsum, potassium sulfate, potassium aluminum sulfate, and combinations thereof.

17. The powder of claim 1 wherein the solid particulate additive is not a catalyst affecting a rate of a reaction between the plaster and the aqueous fluid.

18. An aqueous fluid for activating water soluble components of a three-dimensional printing powder, the aqueous fluid comprising:

water;

a humectant;

a surfactant;

a preservative; and

about 0.05-about 5 wt % of an optical brightening agent;

wherein the fluid is substantially clear, has a viscosity selected from a range of 1-1.35 cps, a surface tension selected from a range of 30-36 dynes/cm, and a pH selected from a range of 4.9 to 10.3.

19. The aqueous fluid of claim 18 wherein the optical brightening agent comprises a fluorescent brightener based on stilbene chemistry or distyrylbiphenyl.

20. A kit comprising:

a powder adapted for three-dimensional printing, the powder comprising;

a loose, dry, and substantially free-flowing particulate mixture comprising;

a water-soluble adhesive;

plaster;

a plaster accelerator;

a whitening agent having an L* of at least about 90 and a C* of up to about 5.5; and

a solid particulate additive comprising an acid, and

an aqueous fluid for activating water soluble components of the powder, the aqueous fluid comprising;

water;

a humectant;

a surfactant;

a preservative; and

about 0.05-about 5 wt % of an optical brightening agent,

wherein (i) the particulate material is adapted for use in three-dimensional printing to form an article comprised of a plurality of layers, the layers including a reaction product of the particulate material and the aqueous fluid that contacts the particulate material during three-dimensional printing, and (ii) the acid has a water solubility selected from a range of about 0-20 g/100 mL of water, a pKa selected from a range about 1 to about 4, and a K_ow selected from a range of -about 0.4 to about 1, and is adapted for modifying a cure rate of an infiltrant to facilitate penetration of the infiltrant into the article, (iii) the particulate mixture is substantially free of plaster retarders, and (iv) the aqueous fluid is substantially clear, has a viscosity selected from a range of 1-1.35 cps, a surface tension selected from a range of 30-36 dynes/cm, and a pH selected from a range 4.9 to 10.3.

21. A method for forming an article by three-dimensional printing, the method comprising the steps of:

providing a loose, dry, and substantially free-flowing particulate mixture comprising a plurality of adjacent particles, the particulate mixture comprising a water-soluble adhesive, plaster, a plaster accelerator, a whitening agent and a solid particulate additive comprising an acid; and

applying to at least some of the plurality of particles an aqueous fluid in an amount sufficient to bond those particles together to define at least a portion of the article, the aqueous fluid comprising water, a humectant, a surfactant, a preservative, and an optical brightening agent,

wherein the defined portion of the article solidifies without mechanical agitation and without supplemental electromagnetic radiation.

22. The method of claim 21, wherein the article formed by the method develops a strength of at least 1 MPa within about one hour of being formed.

23. The method of claim 21, further comprising infiltrating the article with a cyanoacrylate-based adhesive, wherein the article develops a final ultimate infiltrated strength within one hour of infiltration.

24. An essentially solid article manufactured by a three-dimensional printing process, the essentially solid article comprising a product of the reaction of a mixture comprising:

a particulate material including a water-soluble adhesive, a partially soluble filler, an accelerator, an additive having a pKa selected from a range of about 1 to about 4, and a K_ow selected from a range of about −

0.4 to about 1 and a whitening agent; and

an aqueous fluid comprising water, a humectant, a rheology modifier, a surfactant, a preservative, and an optical brightening agent,

wherein the particulate material is reacted with at least a portion of the aqueous fluid to form the essentially solid article including a plurality of essentially evenly distributed layers of the reaction product.

25. The article of claim 24 wherein the article further comprises a cyanoacrylate-based adhesive, and has a final ultimate strength greater than 15 MPa.