WO2023220523A1 - Method for direct coloration of resins for additive manufacturing - Google Patents

Abstract

Provided herein is a method of making a pigmented additive manufacturing resin having a predefined color, which may include the steps of: (a) providing a bulk supply of base additive manufacturing resin; (b) blending, in a first apparatus, a first portion of the bulk supply with (i) one or more colorants, (ii) optionally a white pigment, (iii) optionally a photoinitiator, and (iv) optionally a light absorber, the colorants included in a predefined excess amount, to produce a colored resin concentrate; and then (c) mixing, in a second apparatus, the colored resin concentrate with a second portion of the bulk supply, to produce the pigmented additive manufacturing resin having the predefined color.

Description

METHOD FOR DIRECT COLORATION OF RESINS FOR ADDITIVE MANUFACTURING

Related Applications

This application claims priority from U.S. Provisional Application Serial No. 63/364,383, filed May 9, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

Field

This invention concerns additive manufacturing, and particularly systems and methods for large scale production of colored resins useful for additive manufacturing of consumerfacing products.

Background

Additive manufacturing methods are increasingly being used to make consumer products. Examples include midsoles, helmet liner pads, saddles, backpack pads, and others. Production of products like these requires not just large volumes of resins, but resins in a variety of colors that will both appeal to consumers and enable manufacturers to distinguish their products from those of others with colors distinctive for their brands.

Unlike paints and other resins for coating applications, additive manufacturing resins must be photopolymerized in an additive manufacturing apparatus with ongoing chemical reactions. Indeed, many modern additive manufacturing apparatuses are better viewed as chemical reactors rather than as simple printers. The reactions occurring in such an apparatus often require careful control and balancing of production speed, light intensity, temperature, product accuracy requirements, and other parameters to achieve reliable and consistent product production, and all of these parameters can be further influenced by resin properties and the particular make and model of the apparatus on which additive manufacturing is carried out. All of this makes the production of large quantities of resins in diverse colors suitable for additive manufacturing of consumer-facing products a complicated matter, and new approaches to producing such resins are needed. Summary

Provided herein is a method of making a pigmented additive manufacturing resin having a predefined color, which may include the steps of: (a) providing a bulk supply of base additive manufacturing resin; (b) blending, in a first apparatus, a first portion of the bulk supply with (i) one or more colorants, (ii) optionally a white pigment, (Hi) optionally a photoinitiator, and (iv) optionally a light absorber, the colorants included in a predefined excess amount, to produce a colored resin concentrate; and then (c) mixing, in a second apparatus (such as a meter mix dispense, or “MMD” apparatus), the colored resin concentrate with a second portion of the bulk supply (for example, wherein the volume ratio of said colored resin concentrate to said second portion is in the range of 1:2 or 1 :3 to 1 : 10, 1 :25, or 1 :50), to produce the pigmented additive manufacturing resin having the predefined color. Amounts of colorants, photoinitiator, and any other constituents added during the blending step can be conveniently predefined in small test quantities with the base resin to yield a pigmented additive manufacturing resin having photoabsorbance characteristics appropriate for its use in the intended additive manufacturing apparatus, given the production speeds and accuracy required for the particular product being made.

In some embodiments, (i) said base resin and said pigmented additive manufacturing resin comprise a single part, single cure resin; (ii) said base resin and said pigmented additive manufacturing resin comprise a single part (IK) dual cure resin; (Hi) said pigmented additive manufacturing resin is a mixed (or completed) two-component resin, and said mixing step further includes mixing a second component of said two component resin with said second portion and said colored resin concentrate; or (iv) said pigmented additive manufacturing resin is a first component of a two-component resin, and said mixing step (c) is followed by the step of: (d) mixing, in a third apparatus (e.g., an MMD apparatus) a second component of said two- component resin with said pigmented additive manufacturing resin to provide a dual cure pigmented additive manufacturing resin.

In some embodiments, said pigmented additive manufacturing resin of step (c) and/or (d) has a resin light absorption coefficient (1/um), alpha, of from 0.001 or 0.0015 to 0.003 or 0.004.

In some embodiments, said pigmented additive manufacturing resin of step (c) and/or (d) has: a total colorant concentration of not more than 1, 2, 3 or 4 percent by weight; and/or a total photoinitiator concentration of from 0.1 or 0.2 percent by weight to 1, 3 or 5 percent by weight; and/or a Brookfield viscosity of from 100, 500 or 1,000 centipoise to 30,00 or 50,000 centipoise at 25 degrees Centigrade. In some embodiments, said base additive manufacturing resin comprises: (i) a clear resin; (ii) a translucent resin (for example, a base resin containing white colorant, but insufficient to render that base resin opaque); or (Hi) an opaque tinted resin (for example, a base resin containing white colorant).

In some embodiments, white pigment is included in said blending step and said pigmented additive manufacturing resin comprises an opaque resin. In some embodiments, said white pigment is excluded in said blending step and said pigmented additive manufacturing resin comprises a translucent resin.

In some embodiments, said first apparatus comprises a disposable mixing vessel, and/or a meter mix dispense (MMD) apparatus.

In some embodiments, said second apparatus comprises a meter mix dispense (MMD) apparatus.

In some embodiments, said one or more colorants in said blending step comprise a cyan (C) colorant, a magenta (M) colorant, a yellow (Y) colorant, a black (K) colorant, or any combination thereof.

In some embodiments, said light absorber (c.g, a UV light absorber) is included in said blending step (for example, when the batch of pigmented resin being made is translucent).

In some embodiments, said photoinitiator is included in said blending step (for example, when the pigmented additive manufacturing resin being made is translucent).

In some embodiments, said blending step includes: (i) said one or more colorants; (ii) said white pigment, (Hi) said photoinitiator; and (iv) said light absorber.

In some embodiments, the method further comprises the steps of: (e) dispensing at least a portion of said pigmented additive manufacturing resin to a plurality of additive manufacturing machines; and then (f) producing a plurality of products on said machines, optionally but in some embodiments preferably with the same product being produced on all of said machines; (g) optionally, cleaning said product (e.g., by washing, blowing, draining, centrifugally separating, etc.); and (h) optionally, further curing said product (e.g., by heating, microwave irradiating, contacting to water, or a combination thereof).

In some embodiments, said product comprises a cushion such as a midsole, insole (including orthotic insoles), helmet liner, seat, saddle, or bed cushion, a garment component or a garment liner cushion (such as brassiere or sports bras and cups therein, pads for protective garments such as for motorcycling or motocross, cushions or stiffening elements for gloves including protective (work) gloves and sports gloves (e.g., cricket gloves, baseball gloves, etc.)), wearable cushions (such as backpack pads, shoulder straps, lumbar pads, etc.), and grips and handles for tools, sports equipment or the like (such as grips for hammers, shovels, golf clubs, door handles, etc.).

In some embodiments, said product is flexible or elastic.

In some embodiments, said product is comprised of polyurethane, polyurea, or a copolymer thereof.

In some embodiments, said product is comprised of a lattice (e.g., a strut lattice of repeating unit cells comprised of struts connected at nodes; a surface lattice comprised of repeating unit cells of triply periodic surface lattices, a lofted lattice, or any combination thereof).

The foregoing and other objects and aspects of the present invention are explained in greater detail in the drawings herein and the specification set forth below. The disclosures of all United States patent references cited herein are to be incorporated herein by reference.

Brief Description of the Drawings

Figure 1 is a flow chart illustrating a first embodiment of a process as described herein.

Figure 2 is a flow chart illustrating a second embodiment of a process as described herein.

Detailed Description of Illustrative Embodiments

The present invention is now described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an" and "the" are intended to include plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements components and/or groups or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups or combinations thereof. The sequence of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise. As used herein, the term "and/or" includes any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative ("or").

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and claims and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.

The transitional phrase "consisting essentially of' means that the scope of a claim is to be interpreted to encompass the specified materials or steps recited, and also additional materials or steps that do not materially affect the basic and novel characteristics of the claimed invention as described herein.

1. BASE RESINS.

Base resins for use in the present application may be prepared according to known techniques. Base resins may be single cure or dual cure resins, and may be either single part (IK) resins, or either part of a two part (2K) resin system. The base resins will generally be low, or in some embodiments substantially free, of constituents such as colorants (pigments and/or dyes), and/or photoinitiators, to provide a base resin suitable for the preparation of a variety of final, different colored, resins, that meet the requirements (particularly the photoabsorption requirements) necessary for use in additive manufacturing.

In some embodiments, the base additive manufacturing resin comprises, consists of, or consists essentially of: (i) a clear resin; (ii) a translucent resin (for example, a base resin containing white colorant (e.g., titanium dioxide), but insufficient to render products produced from that base resin opaque); (Hi) an opaque tinted resin (for example, a base resin containing white colorant (e.g., titanium dioxide) sufficient to render products produced from that base resin opaque).

The base resin may be suitable for final resins in a variety of ranges of colorations. In a first example, a base resin is suitable for the preparation of all three of an opaque cyan final resin, an opaque magenta final resin, and an opaque yellow final resin (and thereby suitable for the preparation of a variety of additional colors and shades of resin as well). In another example, a base resin is suitable for the preparation of all seven of an opaque cyan final resin, an opaque magenta final resin, an opaque yellow final resin, an opaque red final resin, an opaque blue final resin, an opaque green final resin, and an opaque black final resin (and thereby suitable for the preparation of a variety of additional colors and shades of resin as well).

In another example, a base resin is suitable for the preparation of all three of a translucent cyan final resin, a translucent magenta final resin, and a translucent yellow final resin (and thereby suitable for the preparation of a variety of additional colors and shades of resin as well, including opaque resins by addition of sufficient additional colorant, particularly white colorant, during the steps described below).

In another example, a base resin is suitable for the preparation of all six of a translucent cyan final resin, a translucent magenta final resin, a translucent yellow final resin, a translucent red final resin, a translucent blue final resin, and a translucent green final resin (and thereby suitable for the preparation of a variety of additional colors and shades of resin as well, including opaque resins by addition of sufficient additional colorant, particularly white colorant, during the steps described below).

Otherwise, the base resin may be prepared in accordance with known techniques from known base resins, including but not limited to those described in, for example, US Patent Nos. 9,211,678; 9,205,601; and 9,216,546. Dual cure resins for additive manufacturing are known and described in, for example: US Patent Nos. 10,975,193; 10,787,583; 10,471,655; 10,350,823; 9,676,963; 9,598,606; and 9,453,142; A. Wright et al., One part moisture curable resins for additive manufacturing, PCT Patent Application Pub. No. WO 2021/173785; Zhu et al., US Pat App Pub Nos. 2020/0392332 and 2022/0089903, and others, the disclosures of all of which are incorporated by reference herein in their entirety. Non-limiting examples of dual cure resins include, but are not limited to, resins for producing objects comprised of polymers such as polyurethane, polyurea, and copolymers thereof; objects comprised of epoxy, cyanate ester or combinations thereof; objects comprised of silicone, etc.

2. COLORATION OF BASE RESINS.

As noted above, a method of making a pigmented additive manufacturing resin having a predefined color, includes the steps of: (a) providing a bulk supply of base additive manufacturing resin: (b) blending, in a first apparatus, a first portion (for example, a portion of 1, 2 or 5 liters to 10, 50 or 100 liters) of the bulk supply with (i) one or more colorants, (ii) optionally a white pigment, (Hi) optionally a photoinitiator, and (iv) optionally a light absorber, the colorants included in a predefined excess amount, to produce a colored resin concentrate; and then (c) mixing, in a second apparatus, the colored resin concentrate with a second portion of the bulk supply (for example, wherein the volume ratio of the colored resin concentrate to the second portion is in the range of 1 :2 or 1 :3 to 1 : 10, 1 :25, or 1 :50), to produce the pigmented additive manufacturing resin having the predefined color. Non-limiting examples of such methods are schematically illustrated in Figure 1 and Figure 2 herein, with additional aspects discussed further below.

In various embodiments of the foregoing:

(i) the base resin and the pigmented additive manufacturing resin comprise, consist of, or consist essentially of a single part, single cure resin (see, e.g, Figure 1);

(ii) the base resin and the pigmented additive manufacturing resin comprise, consist of or consist essentially of a single part (IK) dual cure resin (see, e.g., Figure i);

(Hi) the pigmented additive manufacturing resin is a mixed (or completed) two- component resin, and the mixing step further includes mixing a second component of the two component resin with the second portion and the colored resin concentrate (see, e.g., Figure 2) (though note also that a first component of a two component resin can be prepared as in Figure 1 and then mixed with its corresponding second component at a different place and/or at a different time); or

(iv) the pigmented additive manufacturing resin is a first component of a two- component resin, and the mixing step (c) is followed by the additional step of: (d) mixing, in a third apparatus (e.g., an MMD apparatus) a second component of the two component resin with the batch of pigmented additive manufacturing resin to provide a dual cure pigmented additive manufacturing resin (not shown).

In some preferred embodiments, the final pigmented additive manufacturing resin step (c) and/or (d) has: a resin light absorption coefficient (1/um), alpha, of from 0.001 or 0.0015 to 0.003 or 0.004; and/or a total colorant concentration of not more than 1, 2, 3 or 4 percent by weight; and/or a total photoinitiator concentration of from 0.1 or 0.2 percent by weight to 1, 3 or 5 percent by weight; and/or a Brookfield viscosity of from 100, 500 or 1,000 centipoise to 30,00 or 50,000 centipoise at 25 degrees Centigrade.

Resin photosensitivity (as a measure of suitability of the final resin for use as an additive manufacturing resin) may be determined in advance on a resin sample by any suitable technique, including but not limited to (a) determining penetration depth, D_p, and critical exposure, Ec, to define a working curve for that resin by the working curve equation (see, e.g., Rapid Prototyping and Manufacturing: Fundamentals of Stereolithography, pp. 87-91 (P. Jacobs, Ed. 1992) and Stereolithography and Other RP&M Technologies: from Rapid Prototyping to Rapid Manufacturing, pp. 54-56 (P. Jacobs, Ed. 1996)), (b) determining resin dose-to-cure (resin curing dosage, or De) and resin light absorption (resin absorption coefficient, or alpha) for that resin, as described in J. Tumbleston et al., Continuous liquid interface production of 3D objects, Science xpress (16 Mar. 2015), and variations of the foregoing. See also Tumbleston et al., US Patent Application Pub. No. 2020/0276765.

In some embodiments, white pigment (e.g., titanium dioxide) is included in the blending step and the pigmented additive manufacturing resin comprises an opaque resin; in other embodiments, the white pigment is excluded in the blending step and the pigmented additive manufacturing resin comprises a translucent resin.

In some preferred embodiments, the first (or blending) apparatus comprises a disposable mixing vessel, and may be a batch-type mixing apparatus. In general, the initial blending step may be carried out with any suitable apparatus (e.g., a disposable or reusable tank or vessel, with a stirrer, agitator, shaker, etc.). Suitable apparatuses for the blending step include, but are not limited to, the T 50 digital ULTRA- TURRAX® pilot scale dispensers, available from IKA Works Inc., 2635 Northchase Parkway SE, Wilmington, NC 28405 USA; INDCO high shear dispensers, available from INDCO Inc., 4040 Earnings Way, New Albany, Indiana, 47150 USA, and others. In some embodiments the blending step may be carried out with an MMD apparatus, as discussed in connection with the subsequent mixing step, below.

In some preferred embodiments, the second apparatus comprises a meter mix dispense (MMD) apparatus. Meter mix dispense (MMD) apparatuses are known and available from a variety of sources, including but not limited to METER MIX® Systems US Inc. and DOPAG (US) Ltd., both of 1445 Jamike Ave, 41018 Erlanger, Kentucky, USA. A typical MAID apparatus comprises two or more constituent feed supplies that feed measured (i.e., metered) amounts of the constituents to be mixed into a mixer, from which the mixed product can be dispensed as needed. The mixer is typically a continuous mixer. The feed supplies are typically pumps, such as positive displacement pumps. Suitable positive displacement pumps include, but are not limited to, reciprocating pumps (such as piston, plunger, and diaphragm pumps), rotary pumps (such as gear, lobe, screw, vane, and cam pumps), and piston and plunger pumps operated in single-stroke mode.

"Continuous mixer" as used herein refers to a mixing apparatus into which the ingredients to be mixed are introduced continuously, are mixed as they pass through the mixer, and are then discharged in a continuous operation, as opposd to a "batch mixer." Continuous mixers include both static and dynamic continuous mixers. Dynamic mixers include but are not limited to single screw and twin screw extruders or mixers. Examples include but are not limited to those set forth in US Patent Nos. 3,286,992 (AD Little); 3,945,622 (Beloit); 5,080,493 (3M); 5,249,862 (Thera); 8,651,731 (Sulzer); 9,656,224 (Sulzer); 10,549,246 (P&G), 8,734,609 (Bostik), and variations thereof that will be apparent to those skilled in the art of mixing technology.

Colorants may be pigments or dyes (including luminescent and fluorescent pigments and dyes). In some embodiments, the one or more colorants in the blending step comprise a cyan (C) colorant, a magenta (M) colorant, a yellow (Y) colorant, a black (K) colorant, or any combination thereof.

In addition to colorants, other additives can be added during the blending step to enhance or boost the properties of the ultimate products, including but not limited to fillers, flame retardants, thermal initiators, optical brighteners, UV stablizers, heat stabilizers, biocides, antimicrobial agents (including but not limited antibacterial agents, antifungal agents, antiviral agents, etc.) infra-red light blockers, antioxidants, flow control agents, dispersants, thixotropic agents, dilatants, adhesion promoters, slip additives, anti-slip additives, texturing additives, matting agents, oil resistant additives, water resistant additives, chemical resistant additives, etc.

Additional, and specific, examples of colorants and other additives that may be added to the base resin during the blending step include, but are not limited to, those set forth in LIS Patent Nos. 11,286,395; 11,203,690; 11,134,686; 11 ,001,718; 10,988,227; 10,876,016; 10,563,072; 10,544,309; 10,513,783; 10,370,544; 10,370,543; 10,308,811; 10,288,991 ; 10,975,193; 10,787,583; 10,471,655; 10,280,3161; 10,246,609; 9,902,800, 9,828,516; 9,676,963; 9,359,510; 9,260,583; 9,226,508; 9,199,270; 9,163,129; 9,010,386; and 7,579,389; and US Patent Application Publication Nos. 2021/0246298 and 2002/0188051; the disclosures of which are incorporated by reference herein in their entirety.

In some embodiments, the photoinitiator is included in the blending step (for example, when the pigmented additive manufacturing resin being made is translucent). Any suitable photoiniator, including type I and type II photoinitiators, and including commonly-used UV photoinitiators, can be used. Examples include, but are not limited to, acetophenones (diethoxyacetophenone for example), phosphine oxides such as diphenyl(2,4,6- trimethylbenzoyl)phosphine oxide (TPO) and phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide (PPO), 2,4,6-trimethylbenzoyldi-phenylphosphinate (TPO-L), 2-benzyl-2- (dimethylamino)- l-[4-(morpholinyl) phenyl)] -1-butanone e.g, Irgacure 369), etc. See, e.g., U.S. Pat. No. 9,453,142 to Rolland et al.

In some embodiments, the light absorber (e.g., a UV light absorber) is included in the blending step (for example, when the batch of pigmented resin being made is translucent). Suitable light absorbers include, but are not limited to, naphthalene, anthracene, tetracene, pentacene, and hexacene light absorbing compounds, including but not limited to those set forth in US Patent Application Pub. No. 2020/0024381.

In particular embodiments, the blending step includes at least one, some, or all of:

(i) the one or more colorants (for example, calibrated to provide in the final pigmented resin, not more than one percent by weight generally of a pigment dispersion (or blend of pigment dispersions), such as HOSTATINT™ ST pigment dispersions (available from Clariant Corporation)),

(ii) the white pigment (for example, calibrated to provide in the final pigmented resin, 0.1 to 4.0 percent by weight of a white pigment dispersion having about 50% by weight solid titanium dioxide content, such as HOSTATINT™ AR-100W (available from Clariant Corporation) or Wikoff SCUV-14611 White),

(iii) the photoinitiator (for example, calibrated to provide, in the final pigmented resin, 0.1 to 5 weight percent of TPO, PPO, TPO-L, or Omnipol 910 (available from IGM Resins), or any other suitable photoinitiator), and

(iv) the light absorber (for example, calibrated to provide, in the final pigmented resin, 10 to 2000 parts per million (ppm) of ANTHRACURE™ UVS-1101 9,10-diethoxyanthracene (available from Kawasaki Kasei Chemicals) (other suitable absorbers include, but are not limited to, TINOPAL® OB CO optical brightener (available from BASF), TINUVIN ® UV absorbers (available from BASF), etc.).

3. ADDDITIVE MANUFACTURING.

Once the pigmented additive manufacturing resin is produced as described above, it may be used in any of a variety of additive manufacturing techniques.

Additive manufacturing techniques employing photopolymerizable resins, including bottom-up and top-down techniques, are known and described in, for example, U.S. Patent No. 5,236,637 to Hull, US Patent Nos. 5,391,072 and 5,529,473 to Lawton, U.S. Patent No. 7,438,846 to John, US Patent No. 7,892,474 to Shkolnik, U.S. Patent No. 8,110,135 to El- Siblani, U.S. Patent Application Publication No. 2013/0292862 to Joyce, US Patent Application Publication No. 2013/0295212 to Chen et al. and US Patent No. 5,247,180 to Mitcham and Nelson (Texas Instruments patent describing SLA with micromirror array). The disclosures of these patents and applications are incorporated by reference herein in their entirety.

In some embodiments, the resin is used in a continuous liquid interface production (CLIP) method. CLIP is known and described in, for example, PCT Application Nos. PCT/US2014/015486 (US Patent No. 9,211,678); PCT/US2014/015506 (US Patent No. 9,205,601), PCT/US2014/015497 (US Patent No. 9,216,546), and in J. Tumbleston, D. Shirvanyants, N. Ermoshkin et al., Continuous liquid interface production of 3D Objects, Science 347, 1349-1352 (2015). See also R. Janusziewcz et al., Layerless fabrication with continuous liquid interface production, Proc. Natl. Acad. Sci. USA 113, 11703-11708 (October 18, 2016).

A plurality (or “fleet”) of additive manufacturing apparatus, as may be used for making multiple copies of the same product on a large scale, can be constructed, coordinated, and controlled in accordance with known techniques, such as described in R. Truong et al., Apparatus and Methods for Controlled Validation of Additive Manufacturing Systems, US Patent Application Pub. No. 2021/0354378; A. Hom et al., Robotic Additive Manufacturing System, US Pat. App. Pub No. 2020/0070421; J. DeSimone et al., Integrated Additive Manufacturing System US Pat. App. Pub. No. 2020/0130266; J. DeSimone et al., Integrated Additive Manufacturing System Incorporating Identification Structures, US Pat. App. Pub. No. 2021/087826, and others.

After the products are formed, they are typically cleaned {e.g., by washing, centrifgual separation, wiping/blowing, etc., including combinations thereof), and in some embodiments then further cured, such as by baking, contacting to water, and combinations thereof (although further curing may in some embodiments be concurrent with the first cure, or may be by different mechanisms such as described in US Patent No. 9,453,142 to Rolland et al.).

Thus, in some embodiments, the method may further include the steps of:

(e) dispensing at least a portion of the pigmented additive manufacturing resin (of step (c), or step (d) when present) to a plurality of additive manufacturing machines; and then

(f) producing a plurality of products on the machines, optionally but in some embodiments preferably with the same product being produced on all of the machines;

(g) optionally, cleaning the product e.g., by washing, blowing, draining, centrifugally separating, etc.); and

(h) optionally, further curing the product {e.g., by heating, microwave irradiating, contacting to water, or a combination thereof). Examples of products that can be produced include, but are not limited to, a cushion such as a midsole, insole (including orthotic insoles), helmet liner, seat, saddle, or bed cushion, a garment component or a garment liner cushion (such as brassiere or sports bras and cups therein, pads for protective garments such as for motorcycling or motocross, cushions or stiffening elements for gloves including protective (work) gloves and sports gloves (e.g., cricket gloves, baseball gloves, etc.)), wearable cushions (such as backpack pads, shoulder straps, lumbar pads, etc.), and grips and handles for tools, sports equipment or the like (such as grips for hammers, shovels, golf clubs, door handles, etc.).

The products produced can have any of a variety of properties, depending upon the particular resin used. In some embodiments, the products are rigid, flexible or elastic. As to materials, in some embodiments the products are comprised of of polyurethane, polyurea, or a copolymer thereof; of epoxy, cyanate ester, or a combination thereof; of silicone, or any combination of the foregoing. As to structure, in some embodiments the products are comprised of a lattice (e.g., a strut lattice of repeating unit cells comprised of struts connected at nodes; a surface lattice comprised of repeating unit cells of triply periodic surface lattices, a lofted lattice, or any combination thereof).

The foregoing is illustrative of the present invention, and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims

We claim:

1. A method of making a pigmented additive manufacturing resin having a predefined color, comprising the steps of:

(a) providing a bulk supply of base additive manufacturing resin:

(b) blending, in a first apparatus, a first portion (for example, a portion of 1, 2 or 5 liters to 10, 50 or 100 liters) of said bulk supply with (i) one or more colorants, (ii) optionally a white pigment, (Hi) optionally a photoinitiator, and (iv) optionally a light absorber, the colorants included in a predefined excess amount, to produce a colored resin concentrate; and then

(c) mixing, in a second apparatus, said colored resin concentrate with a second portion of said bulk supply (for example, wherein the volume ratio of said colored resin concentrate to said second portion is in the range of 1 :2 or 1 :3 to 1 : 10, 1 :25, or 1 :50), to produce said pigmented additive manufacturing resin having said predefined color.

2. The method of claim 1, wherein:

(i) said base resin and said pigmented additive manufacturing resin comprise a single part, single cure resin;

(ii) said base resin and said pigmented additive manufacturing resin comprise a single part (IK) dual cure resin;

(Hi) said pigmented additive manufacturing resin is a mixed (or completed) two-component resin, and said mixing step further includes mixing a second component of said two-component resin with said second portion and said colored resin concentrate; or

(iv) said pigmented additive manufacturing resin is a first component of a two- component resin, and said mixing step (c) is followed by the step of: (d) mixing, in a third apparatus (e.g., an MMD apparatus) a second component of said two-component resin with said pigmented additive manufacturing resin to provide a dual cure pigmented additive manufacturing resin.

3. The method of claim 1 or claim 2, wherein: said pigmented additive manufacturing resin of step (c) and/or (d) has a resin light absorption coefficient (1/um), alpha, of from 0.001 or 0.0015 to 0.003 or 0.004.

4. The method of any one of claims 1 to 3, wherein said pigmented additive manufacturing resin of step (c) and/or (d) has: a total colorant concentration of not more than 1, 2, 3 or 4 percent by weight; and/or a total photoinitiator concentration of from 0.1 or 0.2 percent by weight to 1, 3 or 5 percent by weight; and/or a Brookfield viscosity of from 100, 500 or 1,000 centipoise to 30,00 or 50,000 centipoise at 25 degrees Centigrade.

5. The method of any preceding claim, wherein said base additive manufacturing resin comprises:

(i) a clear resin;

(ii) a translucent resin (for example, a base resin containing white colorant, but insufficient to render that base resin opaque); or

(Hi) an opaque tinted resin (for example, a base resin containing white colorant).

6. The method of any preceding claim, wherein white pigment is included in said blending step and said pigmented additive manufacturing resin comprises an opaque resin.

7. The method of any one of claims 1-5, wherein said white pigment is excluded in said blending step and said pigmented additive manufacturing resin comprises a translucent resin.

8. The method of any preceding claim, wherein said first apparatus comprises a disposable mixing vessel, and/or a meter mix dispense (MMD) apparatus.

9. The method of any preceding claim, wherein said second apparatus comprises a meter mix dispense (MMD) apparatus.

10. The method of any preceding claim, wherein said one or more colorants in said blending step comprise a cyan (C) colorant, a magenta (M) colorant, a yellow (Y) colorant, a black (K) colorant, or any combination thereof.

11. The method of any preceding claim, wherein said light absorber (e.g., a UV light absorber) is included in said blending step (for example, when the batch of pigmented resin being made is translucent).

12. The method of any preceding claim, wherein said photoinitiator is included in said blending step (for example, when the pigmented additive manufacturing resin being made is translucent).

13. The method of any preceding claim, wherein said blending step includes:

(i) said one or more colorants;

(ii) said white pigment;

(Hi) said photoinitiator; and

(iv) said light absorber.

14. The method of any preceding claim, further comprising the steps of:

(e) dispensing at least a portion of said pigmented additive manufacturing resin to a plurality of additive manufacturing machines; and then

(f) producing a plurality of products on said machines, optionally but in some embodiments preferably with the same product being produced on all of said machines; and

(g) optionally, cleaning said product (e.g., by washing, blowing, draining, centrifugally separating, etc.); and

(h) optionally, further curing said product (e.g., by heating, microwave irradiating, contacting to water, or a combination thereof).

15. The method of claim 14, wherein said product comprises a cushion such as a midsole, insole (including orthotic insoles), helmet liner, seat, saddle, orbed cushion, a garment component or a garment liner cushion (such as brassiere or sports bras and cups therein, pads for protective garments such as for motorcycling or motocross, cushions or stiffening elements for gloves including protective (work) gloves and sports gloves (e.g., cricket gloves, baseball gloves, etc.)), wearable cushions (such as backpack pads, shoulder straps, lumbar pads, etc.), or grips and handles for tools, sports equipment or the like (such as grips for hammers, shovels, golf clubs, door handles, etc.).

16. The method of claim 14 or 15, wherein said product is flexible or elastic.

17. The method of any one of claims 14 to 16, wherein said product is comprised of polyurethane, polyurea, or a copolymer thereof.

18. The method of any one of claims 14 to 17, wherein said product is comprised of a lattice.

19. The method of claim 18, wherein the lattice is a strut lattice of repeating unit cells comprised of struts connected at nodes, a surface lattice comprised of repeating unit cells of triply periodic surface lattices, a lofted lattice, or any combination thereof.