Compositions and Articles for Additive Manufacturing and Methods of Using the Same

Abstract

The present application relates to compositions and articles for additive manufacturing and methods of use thereof. Such compositions include a compound that induces free radical polymerization, optionally a compound that induces cationic polymerization; a filler component; and a light absorbing component, wherein the composition is configured to have a certain absorbance value at a wavelength commonly used in particle imaging velocimetry testing. In another embodiment, the composition includes a fluorine-antimony-modified compound. Such compositions can be used in particle imaging velocimetry testing methods, wherein the test object utilized is created via additive manufacturing and has a substantially homogeneous structure.

Description

[0001] This application is a divisional application of the invention patent application with the application date of December 19, 2018, application number 201880084297.0, and invention name “Compositions and articles for additive manufacturing and methods of use thereof”. Technical Field

[0002] The present invention relates to radiation curable compositions for additive manufacturing processes, parts cured from said radiation curable compositions, and their use in particle imaging velocimetry testing methods.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims priority to U.S. Provisional Application No. 62 / 612,157, filed December 29, 2017, and U.S. Provisional Application No. 62 / 619,439, filed January 19, 2018, the entire contents of each of which are hereby incorporated by reference in their entirety as if fully set forth herein. Background Art

[0005] Additive manufacturing processes for producing three-dimensional objects are well known. Additive manufacturing processes use computer-aided design (CAD) data of an object to build three-dimensional parts. These three-dimensional parts can be formed from liquid resins, powders, or other materials.

[0006] A non-limiting example of an additive manufacturing process is stereolithography (SL). Stereolithography is a well-known process for quickly producing models, prototypes, patterns and production parts in certain applications. SL uses CAD data of an object, where the data is transformed into a thin cross-section of the three-dimensional object. The data is loaded into a computer, which controls a laser that traces the pattern of the cross-section through a radiation-curable composition contained in a groove, thereby solidifying a thin layer of resin corresponding to the cross-section. The solidified layer is re-coated with resin, and the laser traces another cross-section to harden another layer of resin on top of the previous layer. The process is repeated layer by layer until the three-dimensional object is completed. When initially formed, the three-dimensional object is usually not fully cured and is called a "green model". Although not required, the green model can be subjected to post-curing to enhance the mechanical properties of the manufactured part. An example of the SL process is described in U.S. Patent No. 4,575,330, which is hereby incorporated by reference.

[0007] Several types of lasers are used in stereolithography, traditionally with wavelengths ranging from 193 nm to 355 nm, but other wavelength variations exist. The use of gas lasers to cure radiation-curable compositions is well known. The delivery of laser energy in stereolithography systems can be continuous wave (CW) or Q-switched pulses. CW lasers provide continuous laser energy and can be used in high-speed scanning processes. However, their output power is limited, which reduces the amount of curing that occurs during object creation. Therefore, the finished object will require additional post-processing curing. In addition, excess heat may be generated at the time of irradiation, which may be harmful to the resin. Furthermore, the use of lasers requires scanning the resin point by point, which can be time-consuming.

[0008] Other methods of additive manufacturing utilize lamps or light-emitting diodes (LEDs). LEDs are semiconductor devices that use the phenomenon of electroluminescence to generate light. Currently, LED UV light sources currently emit light with wavelengths between 300 nm and 475 nm, with 365 nm, 390 nm, 395 nm, 405 nm, and 415 nm being common peak spectral outputs. See the textbook "Light-Emitting Diodes," 2nd edition, by E. Fred Schubert, published by Cambridge University Press. E. Fred Schubert 2006 for a more in-depth discussion of LED UV light sources.

[0009] Many additive manufacturing applications require freshly cured parts (also called "green models") to have high mechanical strength (elastic modulus, fracture strength). This property, often referred to as "green strength," constitutes an important characteristic of the green model and is essentially determined by a combination of the properties of the radiation-curable composition employed, the type of equipment used, and the degree of exposure provided during part fabrication. Other important properties of stereolithographic compositions include high sensitivity to the radiation employed during curing, and minimal curling or shrinkage deformation, thereby allowing for high shape definition of the green model. Of course, not only the green model, but also the final cured article should have well-optimized mechanical properties.

[0010] For example, for selective additive manufacturing applications in the aerospace or automotive industries, three-dimensional solid parts are subjected to high force loads in wind tunnels or to extreme temperatures near heat-generating components. In such applications, designers and engineers need to create three-dimensional solid parts via additive manufacturing in a way that maintains their structural integrity and minimizes deflection. Therefore, three-dimensional parts made from photopolymerizable compositions must possess ceramic-like material properties, such as high strength, stiffness, and heat resistance.

[0011] To meet these specialized application design criteria, "filled" radiation-curable compositions have long been used in the art. That is, large amounts of inorganic fillers, such as silicon dioxide (SiO2), have been added to conventional "unfilled" radiation-curable compositions due to the fillers' positive impact on the strength and stiffness of the resulting three-dimensional objects. Such filled liquid radiation-curable compositions are known in the art of additive manufacturing and are disclosed, for example, in U.S. Patent No. 9,228,073, assigned to DSM IP Assets BV.

[0012] As noted, highly filled stereolithography (SL) products produce strong, stiff, high temperature resistant composite parts that have been extensively utilized in wind tunnel testing. Over the past few years, certain post-processed highly filled parts created via SL have been widely used in particle imaging velocimetry testing in wind tunnels to improve R&D efficiency. Prior to particle imaging velocimetry testing, the SL parts are specially prepared to reduce surface reflections when hit by a high intensity green laser. Preparing the parts typically takes hours or days, and due to the sensitive test conditions and environments in which such parts are evaluated, existing invasive methods of surface treating SL parts may not always promote accurate results.

[0013] Particle imaging velocimetry (PIV) is a quantitative method that uses a combination of a high-intensity light source, a digital camera, and seed particles commonly referred to as tracers to provide accurate velocity measurements of the flow field being studied. The method is well known, as described in Particle Image Velocimetry: A Practical Guide, Second Edition (2007) by Markus Raffel, Christian E. Willert, Steven T. Wereley, and Jurgen Kompenhans. Neutral buoyant particles that closely represent a fluid (usually air) are typically broadcast into the flow. Intense light, such as from a high-power laser, is then used in combination with one or more digital cameras to collect two images with a small separation time. These images are then cross-correlated or autocorrelated, and the resulting calculation produces a velocity vector. PIV can be said to be the result of the development of flow visualization technology, which has made a very important contribution to understanding fluid flow phenomena. Flow visualization may always play an important role in the study of fluid motion.

[0014] Since at least 2006, PIV testing has been used to improve the aerodynamic design of air-sensitive objects. This type of testing is used in wind tunnels to visualize airflow behavior and study the aerodynamic effects of SL-manufactured prototype parts. Consequently, permanent PIV testing rigs have been attached to wind tunnels in the racing industry for at least 10 years. Over the past decade, racing engineers have widely used these systems to improve R&D efficiency and produce cars with ever-increasing amounts of downforce.

[0015] A common concern during PIV testing is the surface reflections produced by the high intensity lasers that are necessarily used therein. The severity of the reflections is influenced in part by the material being used, the intensity of the light source, and the application of image filtering. The material selected can have a major influence on the severity of the surface reflections. High surface reflections alter the PIV test data near the surface of the part, causing the image to appear blurred. Due to the inherently highly reflective surfaces of SL parts, engineers have not until now been able to apply SL parts directly to PIV testing. Engineers typically post-process the surfaces of SL parts by wrapping the parts with special metal foils or painting the surface of the parts to ensure that they perform well in PIV testing. Post-processing is time consuming and often introduces new challenges depending on the processing method used.

[0016] Painting or "foiling" SL parts is currently the most popular treatment method. To implement these methods, surface defects on the SL part must first be eliminated in a labor-intensive sandblasting process. Then, a metal foil or paint (such as matte black or orange paint) is usually applied or sprayed onto the surface and allowed to dry. The paint may contain hazardous chemicals, and the uniformity of the paint thickness is difficult to control when the shape or geometry of the SL part becomes complex. In addition, the paint layer may sometimes be partially worn away during testing or handling. At the same time, the precise application of the foil is difficult and requires great skill to apply it to the part without causing bubbles or surface defects on the part. In any case, the known methods compromise the dimensional fidelity of the test part, thereby introducing the possibility of error when determining the actual wind flow around the prototype aerodynamic component. Although test parts created via additive manufacturing methods have been used in such PIV tests for many years, such parts do not exist to date that eliminate the need for time-consuming post-processing involving potentially hazardous chemicals and compromising the accuracy of the precisely manufactured SL parts.

[0017] From the foregoing, it is apparent that there does not exist a radiation-curable composition for additive manufacturing that is suitable for producing cured parts having sufficient application-specific heat resistance and structural rigidity while overcoming the long-standing but unresolved industry need to provide a resin that can produce parts that can achieve accurate PIV testing without the need for post-processing and yet still cure quickly enough to be suitable for use in additive manufacturing processes. Summary of the Invention

[0018] The aforementioned problems are overcome by aspects of the invention described and claimed herein. A first aspect of the claimed invention is a method of performing particle imaging velocimetry testing using an object created via additive manufacturing, the method comprising:

[0019] providing a test part created via additive manufacturing; immersing the test part in a flow field seeded with tracer particles;

[0020] illuminating at least a portion of the broadcast flow field proximate the component with light of a first wavelength;

[0021] capturing a plurality of images using an imaging system; evaluating the images to determine a flow vector proximate the test part;

[0022] The test parts were uncoated, unfoiled and unpainted.

[0023] A second aspect of the present invention is a radiation curable composition for additive manufacturing, the radiation curable composition comprising:

[0024] a free radical polymerizable component;

[0025] Free radical photoinitiators;

[0026] Filler ingredients;

[0027] and light absorbing components;

[0028] wherein the composition is configured to have an absorbance at 532 nm of at least 10, or at least 15, or at least 20, or at least 25, or at least 30, or 10-1000, or 15-500, or 20-200, or 25-150, or 30-100, or 30-80, or 35-75.

[0029] A third aspect of the claimed invention is a radiation curable composition for additive manufacturing comprising, relative to the weight of the total composition:

[0030] a. 25-65% by weight of a filler component;

[0031] b. 10-50% by weight of a cationically polymerizable component;

[0032] c. 5-40% by weight of a free radical polymerizable component;

[0033] d. an effective amount of a cationic photoinitiator;

[0034] e. an effective amount of a free radical photoinitiator; and

[0035] f. Light absorbing components. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Depicted is a particle imaging velocimetry test setup into which articles formed from compositions according to the present invention may be incorporated. DETAILED DESCRIPTION

[0037] As used herein, "substantially homogeneous construction" refers to an object having a substantially uniform appearance and composition. For purposes herein, parts created via a groove-based additive manufacturing process (e.g., stereolithography) are considered herein as non-limiting examples of parts having a "substantially homogeneous construction," even if such parts are the cured product of a resin comprising a suspension of solid particles (e.g., nanosilica) dispersed in a liquid resin. Examples of objects that should not be considered "substantially homogeneous construction" for purposes herein include parts that are post-processed by painting the cured object, or parts where metal foil is attached to at least a portion of the outer surface of the cured object.

[0038] A first aspect of the claimed invention is a method of performing particle imaging velocimetry testing using an object created via additive manufacturing, the method comprising:

[0039] providing a test part created via additive manufacturing; immersing the test part in a flow field seeded with tracer particles;

[0040] illuminating at least a portion of the broadcast flow field proximate the component with light of a first wavelength;

[0041] capturing a plurality of images using an imaging system; evaluating the images to determine a flow vector proximate the test part;

[0042] The test parts were uncoated, unfoiled and unpainted.

[0043] A second aspect of the present invention is a radiation curable composition for additive manufacturing, the radiation curable composition comprising:

[0044] a free radical polymerizable component;

[0045] Free radical photoinitiators;

[0046] Filler ingredients;

[0047] and light absorbing components;

[0048] wherein the composition is configured to have an absorbance at 532 nm of at least 10, or at least 15, or at least 20, or at least 25, or at least 30, or 10-1000, or 15-500, or 20-200, or 25-150, or 30-100, or 30-80, or 35-75.

[0049] A third aspect of the claimed invention is a radiation curable composition for additive manufacturing comprising, relative to the weight of the total composition:

[0050] g.25-65% by weight of a filler component;

[0051] h. 10-50% by weight of a cationically polymerizable component;

[0052] i. 5-40% by weight of a free radical polymerizable component;

[0053] j. an effective amount of a cationic photoinitiator;

[0054] k. an effective amount of a free radical photoinitiator; and

[0055] 1. Light absorbing components.

[0056] Cationic polymerizable component

[0057] According to some preferred embodiments, the radiation-curable compositions for addition manufacturing of the present invention comprise at least one cationically polymerizable component; i.e., a component that undergoes polymerization initiated by cations or in the presence of an acid generator. The cationically polymerizable component can be a monomer, oligomer, and / or polymer, and can contain one or more aliphatic, aromatic, cycloaliphatic, araliphatic, heterocyclic moieties, and any combination thereof. Suitable cyclic ether compounds can contain cyclic ether groups as pendant groups, or groups that form part of an alicyclic or heterocyclic ring system.

[0058] The cationically polymerizable component is selected from the group consisting of cyclic ether compounds, cyclic acetal compounds, cyclic thioether compounds, spiroorthoester compounds, cyclic lactone compounds, and vinyl ether compounds, and any combination thereof.

[0059] Suitable cationic polymerizable components include cyclic ether compounds (such as epoxy compounds and oxetanes), cyclic lactone compounds, cyclic acetal compounds, cyclic sulfide compounds, spirocyclic orthoester compounds, and vinyl ether compounds. Specific examples of cationic polymerizable components include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)-cyclohexane-1,4-dioxane, bis(3,4-epoxycyclohexylmethyl)adipic acid Ester, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, vinylcyclohexene dioxide, limonene oxide, limonene dioxide, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate, ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, trimethylcaprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone-modified 3,4-epoxycyclohexylmethyl-3',4'- Oxycyclohexane carboxylate, methylene bis(3,4-epoxycyclohexane), dicyclohexyl-3,3'-epoxide, bis(3,4-epoxycyclohexyl) with -O-, -S-, -SO-, -SO2-, -C(CH3)2-, -CBr2-, -C(CBr3)2-, -C(CF3)2-, -C(CCl3)2- or -CH(C6H5)- bonds, dicyclopentadiene diepoxide, bis(3,4-epoxycyclohexyl methyl) ether of ethylene glycol, ethylene bis(3,4-epoxycyclohexanecarboxylate), phthalic acid epoxyhexahydrodioctyl ester, phthalic acid epoxyhexahydro-di-2 -ethylhexyl ester, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, diglycidyl ester of aliphatic long-chain dibasic acid, monoglycidyl ether of aliphatic higher alcohol, phenol, cresol, monoglycidyl ether of butylphenol, or polyether alcohols obtained by adding alkylene oxide to these compounds, glycidyl ester of higher fatty acid, epoxidized soybean oil, epoxybutyl stearic acid, epoxyoctyl stearic acid, epoxidized linseed oil, epoxidized polybutadiene, 1,4-Bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3-(3-hydroxypropyl)oxymethyloxetane, 3-ethyl-3-(4-hydroxybutyl)oxymethyloxetane, 3-ethyl-3-(5-hydroxypentyl)oxymethyloxetane, 3-ethyl-3-phenoxymethyloxetane, bis((1-ethyl(3-oxetane) methyl) ether, 3-ethyl-3-((2-ethylhexyloxy)methyl)oxetane, 3-ethyl-((triethoxysilylpropoxymethyl)oxetane, 3-(methyl)-allyloxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanylmethoxy)methylbenzene, 4-fluoro-[1-(3-ethyl-3-oxetanylmethoxy)] methyl]benzene, 4-methoxy-[1-(3-ethyl-3-oxetanylmethoxy)methyl]-benzene, [1-(3-ethyl-3-oxetanylmethoxy)ethyl]phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, ethyl diethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3- ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, and any combination thereof.

[0060] The cationically polymerizable component may also optionally contain multifunctional materials, including dendritic polymers having epoxy or oxetane functional groups, such as dendritic macromolecules, linear dendritic polymers, dendritic graft polymers, hyperbranched polymers, star-branched polymers, and hypergrafted polymers. The dendritic polymers may contain one type of polymerizable functional group or different types of polymerizable functional groups, such as epoxy functional groups and oxetane functional groups.

[0061] In one embodiment, the composition of the present invention further comprises one or more monoglycidyl ethers or polyglycidyl ethers of aliphatic alcohols, aliphatic polyols, polyester polyols or polyether polyols. Examples of preferred components include 1,4-butanediol diglycidyl ether, glycidyl ethers of polyoxyethylene and polyoxypropylene glycols and triols having a molecular weight of about 200 to about 10,000; and glycidyl ethers of polytetramethylene glycol or poly(oxyethylene-oxybutylene) random or block copolymers. In a specific embodiment, the cationic polymerizable component comprises a multifunctional glycidyl ether lacking a cyclohexane ring in the molecule. In another specific embodiment, the cationic polymerizable component comprises neopentyl glycol diglycidyl ether. In another specific embodiment, the cationic polymerizable component comprises 1,4-cyclohexanedimethanol diglycidyl ether.

[0062] An example of a commercially available preferred polyfunctional glycidyl ether is Erisys TM GE 22 (Erisys TM Products are available from Emerald Performance Materials TM Purchased), Heloxy TM 48. Heloxy TM 67. Heloxy TM 68. Heloxy TM 107(Heloxy TM modifiers available from Momentive Specialty Chemicals), and F713. Examples of commercially available preferred monofunctional glycidyl ethers are Heloxy TM 71. Heloxy TM 505、Heloxy TM 7. Heloxy TM 8 and Heloxy TM 61.

[0063] In one embodiment, the epoxide is 3,4-epoxycyclohexylmethyl-3',4-epoxycyclohexanecarboxylate (available as CELLOXIDE TM 2021P was purchased from Daicel Chemical or as CYRACURE TM UVR-6105 is available from Dow Chemical), epoxy resin based on hydrogenated bisphenol A-epichlorohydrin (available as EPON TM 1510 available from Momentive), 1,4-cyclohexanedimethanol diglycidyl ether (available as HELOXY TM107 available from Momentive), hydrogenated bisphenol A diglycidyl ether (available as EPON TM 825 available from Momentive), a mixture of dicyclohexyl diepoxide and nanosilica (available as NANOPOX TM purchased), and any combination thereof.

[0064] The above-mentioned cationic polymerizable compounds can be used alone or in combination of two or more thereof. In some embodiments of the present invention, the cationic polymerizable component further comprises at least two different epoxy components. In one embodiment, the cationic polymerizable component comprises a cycloaliphatic epoxy resin, for example, an alicyclic epoxy having 2 or more epoxy groups. In another embodiment, the cationic polymerizable component comprises an epoxy having an aromatic or aliphatic glycidyl ether group with 2 (difunctional) or more than 2 (multifunctional) epoxy groups.

[0065] Thus, radiation curable compositions for additive manufacturing may include a suitable amount of a cationically polymerizable component, for example, in certain embodiments, from about 10% to about 80% by weight of the composition, in other embodiments, from about 20% to about 70% by weight of the composition, and in other embodiments, from about 25% to about 65% by weight of the composition.

[0066] In other embodiments of the present invention, the cationically polymerizable component optionally comprises an oxetane component. In a specific embodiment, the cationically polymerizable component comprises an oxetane, such as an oxetane containing 1, 2 or more than 2 oxetane groups. If utilized in the composition, the oxetane component is present in an appropriate amount of from about 5% by weight to about 30% by weight of the composition. In another embodiment, the oxetane component is present in an amount of from about 10% by weight to about 25% by weight of the composition, and in yet another embodiment, the oxetane component is present in an amount of from 20% by weight to about 30% by weight of the composition.

[0067] According to one embodiment, the radiation curable composition for addition manufacturing contains components that can be polymerized by both free radical polymerization and cationic polymerization. The example of this type of polymerizable component is a vinyloxy compound, for example, a vinyloxy compound selected from the group consisting of: bis(4-vinyloxybutyl)isophthalate, tris(4-vinyloxybutyl)trimellitate, and combinations thereof. Other examples of this type of polymerizable component include those containing acrylate and epoxy groups or acrylate and oxetane groups on the same molecule.

[0068] Free radical polymerizable components

[0069] According to a preferred embodiment of the present invention, the radiation-curable composition for additive manufacturing of the present invention comprises at least one free-radically polymerizable component, i.e., a component that undergoes polymerization initiated by free radicals. Free-radically polymerizable components are monomers, oligomers, and / or polymers; they are monofunctional or multifunctional materials, i.e., they have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10…20…30…40…50…100 or more functional groups that can be polymerized by free radical initiation, and may contain one or more aliphatic, aromatic, cycloaliphatic, araliphatic, heterocyclic moieties, or any combination thereof. Examples of multifunctional materials include dendritic polymers, such as dendritic macromolecules, linear dendrimers, dendritic graft polymers, hyperbranched polymers, star-branched polymers, and hypergrafted polymers; see, for example, US 2009 / 0093564 A1. Dendrimers may contain one type of polymerizable functional groups or different types of polymerizable functional groups, such as acrylate and methacrylate functional groups.

[0070] Examples of free radical polymerizable components include acrylates and methacrylates, such as isobornyl (meth)acrylate, bornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 4-butylcyclohexyl (meth)acrylate, acryloylmorpholine, (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate. , methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, caprolactone acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, (meth) Decyl acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxydiethylene glycol (meth)acrylate 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate, 1,2-Diamond (meth)acrylate,

[0071] Examples of the polyfunctional free radical polymerizable component include those having a (meth)acryloyl group, such as trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, ethylene glycol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, dicyclopentadienyl dimethanol di(meth)acrylate, [2-[1,1-dimethyl-2-[(1-oxoallyl)oxy]ethyl]-5-ethyl-1,3-dioxan-5-yl]methyl acrylate; 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane dipentaerythritol monohydroxypenta(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, propoxylated neopentyl glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, glycerol tri(meth)acrylate, mono(meth)acrylate phosphate and di(meth)acrylate phosphate, di(meth)acrylate C7-C 20 alkyl esters, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tricyclodecanediyldimethyl di(meth)acrylate, and alkoxylated versions (e.g., ethoxylated and / or propoxylated) of any of the foregoing monomers, as well as di(meth)acrylates of diols that are ethylene oxide or propylene oxide adducts of bisphenol A, di(meth)acrylates of diols that are ethylene oxide or propylene oxide adducts of hydrogenated bisphenol A, epoxy(meth)acrylates of (meth)acrylate adducts of bisphenol A that are diglycidyl ethers, diacrylates of polyoxyalkylated bisphenol A and triethylene glycol divinyl ether, and adducts of hydroxyethyl acrylate.

[0072] According to one embodiment, the radical polymerizable component is a multifunctional (meth) acrylate. The multifunctional (meth) acrylate may include all methacryloyl groups, all acryloyl groups, or any combination of methacryloyl groups and acryloyl groups. In one embodiment, the radical polymerizable component is selected from the group consisting of bisphenol A diglycidyl ether di(meth) acrylate, ethoxylated or propoxylated bisphenol A or bisphenol F di(meth) acrylate, dicyclopentadiene dimethanol di(meth) acrylate, acrylic acid [2-[1,1-dimethyl-2-[(1-oxoallyl)oxy]ethyl]-5-ethyl-1,3-dioxane-5-yl]methyl ester, dipentaerythritol monohydroxypenta(meth) acrylate, dipentaerythritol penta(meth) acrylate, dipentaerythritol hexa(meth) acrylate, propoxylated trimethylolpropane tri(meth) acrylate, and propoxylated neopentyl glycol di(meth) acrylate, and any combination thereof.

[0073] In a preferred embodiment, the multifunctional (meth)acrylate has greater than 2, more preferably greater than 3, and more preferably greater than 4 functional groups.

[0074] In another preferred embodiment, the free radical polymerizable component consists solely of a single multifunctional (meth)acrylate component. In other embodiments, the exclusive free radical polymerizable component is tetrafunctional, in other embodiments, the exclusive free radical polymerizable component is pentafunctional, and in other embodiments, the free radical polymerizable component is hexafunctional.

[0075] In another embodiment, the free radical polymerizable component is selected from the group consisting of bisphenol A diglycidyl ether diacrylate, dicyclopentadiene dimethanol diacrylate, [2-[1,1-dimethyl-2-[(1-oxoallyl)oxy]ethyl]-5-ethyl-1,3-dioxan-5-yl]methyl acrylate, dipentaerythritol monohydroxypentaacrylate, propoxylated trimethylolpropane triacrylate, and propoxylated neopentyl glycol diacrylate, and any combination thereof.

[0076] In a specific embodiment, the radiation curable composition for additive manufacturing of the present invention comprises one or more of the following: bisphenol A diglycidyl ether di(meth)acrylate, dicyclopentadiene dimethanol di(meth)acrylate, dipentaerythritol monohydroxy penta(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate and / or propoxylated neopentyl glycol di(meth)acrylate, and more specifically comprises one or more of the following: bisphenol A diglycidyl ether diacrylate, dicyclopentadiene dimethanol diacrylate, dipentaerythritol pentaacrylate, propoxylated trimethylolpropane triacrylate and / or propoxylated neopentyl glycol diacrylate.

[0077] The above-mentioned free radical polymerizable compounds can be used alone or in combination of two or more thereof. The radiation curable composition for addition fabrication can contain any suitable amount of the free radical polymerizable component, for example, in certain embodiments, the amount of the free radical polymerizable component is up to about 40% by weight of the composition, in certain embodiments, from about 2% to about 40% by weight of the composition, in other embodiments, from about 5% to about 30% by weight of the composition, and in other embodiments, from about 10% to about 20% by weight of the composition.

[0078] Hydroxyl functional components

[0079] Many known radiation curable compositions for additive manufacturing utilize hydroxyl functional compounds to enhance the properties of parts made from these compositions.

[0080] In certain embodiments of the present invention, the composition may optionally contain a hydroxyl-functional component. The hydroxyl-containing material that can be used in the present invention can be any suitable organic material having a hydroxyl functionality of at least 1. If present, the material is preferably substantially free of any groups that interfere with the curing reaction or are thermally or photolytically unstable.

[0081] If present, any hydroxyl groups may be used for a specific purpose. If present, the hydroxyl-containing material preferably contains one or more aliphatic primary or secondary hydroxyl groups. The hydroxyl groups may be internal or terminal in the molecule. Monomers, oligomers, or polymers may be used. The hydroxyl equivalent weight (i.e., the number average molecular weight divided by the number of hydroxyl groups) is preferably in the range of 31 to 5000.

[0082] Representative examples of hydroxyl-containing materials having a hydroxyl functionality of 1 include alkanols, monoalkyl ethers of polyoxyalkylene glycols, monoalkyl ethers of alkylene glycols, and the like, and combinations thereof.

[0083] Representative examples of monomeric polyhydroxy organic materials include alkylene and aryl alkylene diols and polyols, such as 1,2,4-butanetriol, 1,2,6-hexanetriol, 1,2,3-heptanetriol, 2,6-dimethyl-1,2,6-hexanetriol, (2R,3R)-(-)-2-benzyloxy-1,3,4-butanetriol, 1,2,3-hexanetriol, 1,2,3-butanetriol, 3-methyl-1,3,5-pentanetriol, 1,2,3-cyclohexanetriol, 1,3,5-cyclohexanetriol, 3,7,11,15-tetramethyl-1,2,3-hexadecantriol, 2-hydroxymethyltetrahydropyran-3,4,5-triol, 2,2,4,4-tetramethyl- 1,3-cyclobutanediol, 1,3-cyclopentanediol, trans-1,2-cyclooctanediol, 1,16-hexadecanediol, 3,6-dithio-1,8-octanediol, 2-butyne-1,4-diol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1-phenyl-1,2-ethanediol, 1,2-cyclohexanediol, 1,5-decalinediol, 2,5-dimethyl-3-hexyne-2,5-diol, 2,7-dimethyl-3,5-octadiyn-2-7-diol, 2,3-butanediol, 1,4-cyclohexanedimethanol, and combinations thereof.

[0084] Representative examples of oligomeric and polymeric hydroxyl-containing materials include polyoxyethylene and polyoxypropylene diols and triols having molecular weights ranging from about 200 to about 10,000; polytetramethylene glycols of varying molecular weights; poly(oxyethylene-oxybutylene) random or block copolymers; copolymers containing pendant hydroxyl groups formed by hydrolysis or partial hydrolysis of vinyl acetate copolymers, polyvinyl acetal resins containing pendant hydroxyl groups; hydroxyl-terminated polyesters and hydroxyl-terminated polylactones; hydroxyl-functionalized polyalkadienes, such as polybutadiene; aliphatic polycarbonate polyols, such as aliphatic polycarbonate diols; and hydroxyl-terminated polyethers, and combinations thereof.

[0085] If present, preferred hydroxyl-containing monomers include 1,4-cyclohexanedimethanol and aliphatic and cycloaliphatic monohydroxy alkanols. Such preferred hydroxyl-containing oligomers and polymers include hydroxyl and hydroxy / epoxy functionalized polybutadiene, polycaprolactone diols and triols, ethylene / butylene polyols, and monohydroxy functional monomers. Preferred examples of polyether polyols are polypropylene glycols of various molecular weights, and glycerol propoxylate-B-ethoxylate triols. Particularly preferred, if present, are linear and branched polytetramethylene glycols, which are available in various molecular weights, for example, in the range of 150-4000 g / mol, preferably in the range of 150-1500 g / mol, and more preferably in the range of 150-750 g / mol.

[0086] If present, the composition preferably comprises at most 10 wt%, more preferably at most 5 wt%, and most preferably at most 2 wt% of one or more non-free radically polymerizable hydroxy-functional compounds relative to the total weight of the composition.

[0087] In a preferred embodiment, the radiation-curable composition for additive manufacturing of the present invention includes a photoinitiator system. The photoinitiator system may include a free radical photoinitiator and / or a cationic photoinitiator. According to one embodiment, the radiation-curable composition includes a photoinitiator system containing at least one photoinitiator having a cationic initiation function and at least one photoinitiator having a free radical initiation function. In addition, the photoinitiator system may include a photoinitiator containing both free radical initiation functions and cationic initiation functions on the same molecule. The photoinitiator is a compound that chemically changes due to the action of light or the synergistic effect between the action of light and the electronic excitation of a sensitizing dye to produce at least one of free radicals, acids and bases.

[0088] Cationic photoinitiator

[0089] According to one embodiment, the radiation curable composition comprises a cationic photoinitiator. The cationic photoinitiator initiates cationic ring-opening polymerization upon light irradiation.

[0090] In one embodiment, any suitable cationic photoinitiator may be used, for example, a cationic photoinitiator having a cation selected from the group consisting of onium salts, halonium salts, oxyiodonium salts, selenium salts, sulfonium salts, sulfoxide salts, diazonium salts, metallocene salts, isoquinolinium salts, phosphonium salts, arsenic salts, troponium salts, dialkylbenzoylsulfonium salts, thiopyrilium salts, diaryliodonium salts, triarylsulfonium salts, ferrocene, bis(cyclopentadienyliron)arene salt compounds, and pyridinium salts, and any combination thereof.

[0091] In another embodiment, the cation of the cationic photoinitiator is selected from the group consisting of: aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene-based compounds, aromatic phosphonium salts, and any combination thereof. In another embodiment, the cation is a polymeric sulfonium salt, such as in US5380923 or US5047568, or other aromatic heteroatom-containing cations and naphthylsulfonium salts, such as in US7611817, US7230122, US2011 / 0039205, US2009 / 0182172, US7678528, EP2308865, WO2010046240 or EP2218715. In another embodiment, the cationic photoinitiator is selected from the group consisting of: triarylsulfonium salts, diaryliodonium salts and metallocene-based compounds, and any combination thereof. Onium salts, such as iodonium and sulfonium salts, and ferrocenium salts, have the advantage that they are generally more thermally stable.

[0092] In a specific embodiment, the cationic photoinitiator has an anion selected from the group consisting of: BF4 - 、AsF6 - 、SbF6 - PF6 - 、[B(CF3)4] - 、B(C6F5)4 - 、B[C6H3-3,5(CF3)2]4 - 、B(C6H4CF3)4 - 、B(C6H3F2)4 - 、B[C6F4-4(CF3)]4 - 、Ga(C6F5)4 -- 、[(C6F5)3B-C3H3N2-B(C6F5)3] - 、[(C6F5)3B-NH2-B(C6F5)3] - , tetrakis(3,5-difluoro-4-alkoxyphenyl)borate anion, tetrakis(2,3,5,6-tetrafluoro-4-alkoxyphenyl)borate anion, perfluoroalkylsulfonate anion, tris[(perfluoroalkyl)sulfonyl]methide anion, bis[(perfluoroalkyl)sulfonyl]imide anion, perfluoroalkylphosphate anion, tris(perfluoroalkyl)trifluorophosphate anion, bis(perfluoroalkyl)tetrafluorophosphate anion, tris(pentafluoroethyl)trifluorophosphate anion and (CH6B 11 Br6) - 、(CH6B 11 Cl6) - and other halocarborane anions.

[0093] A survey of other onium salt initiators and / or metallocene salts can be found in "UV Curing, Science and Technology" (Editor SPP Appas, Technology Marketing Corp., 642 Westover Road, Stamford, Conn., USA) or "Chemistry & Technology of UV & EB Formulation for Coatings, Inks & Paints", Volume 3 (Editor PKT Oldring).

[0094] In one embodiment, the cationic photoinitiator has a cation selected from the group consisting of aromatic sulfonium salts, aromatic iodonium salts, and metallocene-based compounds and at least one selected from the group consisting of SbF6 - PF6 - 、B(C6F5)4 - 、[B(CF3)4] - , tetrakis(3,5-difluoro-4-methoxyphenyl)borate anion, perfluoroalkylsulfonate anion, perfluoroalkylphosphate anion, tris[(perfluoroalkyl)sulfonyl]methide anion and [(C2F5)3PF3] - The group consisting of anions.

[0095] Examples of cationic photoinitiators useful for curing at 300-475 nm, particularly 365 nm UV light, without a sensitizer include 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate, 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium tetrakis(pentafluorophenyl)borate, 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium tetrakis(3,5-difluoro-4-methyloxyphenyl)borate, 4-[4-(3-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium tetrakis(2,3,5,6-tetrafluoro-4-methyloxyphenyl)borate, tris(4-(4-acetylphenyl)phenylthio)sulfonium tetrakis(pentafluorophenyl)borate (available from BASF). PAG 290), tris(4-(4-acetylphenyl)phenylthio)sulfonium tris[(trifluoromethyl)sulfonyl]methide (from BASF GSID 26-1), tris(4-(4-acetylphenyl)phenylthio)sulfonium hexafluorophosphate (from BASF 270), and HS-1 available from San-Apro Ltd.

[0096] Preferred cationic photoinitiators include the following, alone or in mixtures: bis[4-diphenylsulfoniumphenyl]sulfide bishexafluoroantimonate; thiophenoxyphenylsulfonium hexafluoroantimonate (available as Chivacure 1176 from Chitec), tris(4-(4-acetylphenyl)phenylthio)sulfoniumtetrakis(pentafluorophenyl)borate (available as PAG 290), tris(4-(4-acetylphenyl)phenylthio)sulfonium tris[(trifluoromethyl)sulfonyl]methide (from BASF GSID26-1) and tris(4-(4-acetylphenyl)phenylthio)sulfonium hexafluorophosphate (from BASF 270), [4-(1-methylethyl)phenyl](4-methylphenyl)iodonium tetrakis(pentafluorophenyl)borate (available from Rhodia as Rhodorsil 2074), 4-[4-(2-chlorobenzoyl)phenylthio]phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate (such as SP-172 from Adeka), SP-300 from Adeka, and compounds with an anion (PF 6-m (C n F 2n+1 ) m ) - An aromatic sulfonium salt wherein m is an integer from 1 to 5 and n is an integer from 1 to 4 (available as CPI-200K or CPI-200S, which are monovalent sulfonium salts from San-Apro Ltd.; TK-1 available from San-Apro Ltd., or HS-1 available from San-Apro Ltd.).

[0097] In various embodiments, the radiation curable compositions for additive manufacturing can be irradiated by laser or LED light operating at any wavelength in the UV or visible spectrum. In particular embodiments, the radiation is from a laser or LED emitting a wavelength between 340 nm and 415 nm. In particular embodiments, the laser or LED source emits a peak wavelength of approximately 340 nm, 355 nm, 365 nm, 375 nm, 385 nm, 395 nm, 405 nm, or 415 nm.

[0098] In one embodiment of the present invention, the radiation curable composition for additive manufacturing comprises an aromatic triarylsulfonium salt cationic photoinitiator.

[0099] The use of aromatic triarylsulfonium salts in addition manufacturing applications is known. See US 20120251841 to DSM IP Assets, BV (which is hereby incorporated in its entirety), U.S. Patent No. 6,368,769 to Asahi Denki Kogyo, which discusses aromatic triarylsulfonium salts with tetraarylborate anions (including tetrakis(pentafluorophenyl)borate anions), and the use of said compounds in stereolithography applications. Triarylsulfonium salts are disclosed, for example, in J Photopolymer Science & Tech (2000), 13(1), 117-118 and J Poly Science, Part A (2008), 46(11), 3820-29. - 、AsF6 - PF6 - and SbF6 - ) triarylsulfonium salt Ar3S + MX - Published in J Polymer Sci, Part A (1996), 34(16), 3231-3253.

[0100] The use of aromatic triarylsulfonium salts as cationic photoinitiators in radiation curable compositions is desirable in addition manufacturing processes because the resulting resins achieve fast photospeeds, good thermal stability, and good light stability.

[0101] In one embodiment, the cationic photoinitiator is an aromatic triarylsulfonium salt, more specifically an R-substituted aromatic thioether triarylsulfonium tetrakis(pentafluorophenyl)borate cationic photoinitiator having a tetrakis(pentafluorophenyl)borate anion and a cation of the following formula (I):

[0102]

[0103] wherein Y1, Y2 and Y3 are the same or different, and wherein Y1, Y2 or Y3 is an aromatic sulfide substituted with R, wherein R is an acetyl group or a halogen group.

[0104] In one embodiment, Y1, Y2 and Y3 are the same. In another embodiment, Y1 and Y2 are the same, but Y3 is different. In another embodiment, Y1, Y2 or Y3 is an aromatic thioether substituted with R, wherein R is an acetyl group or a halogen group. Preferably, Y1, Y2 or Y3 is an aromatic thioether substituted with R, wherein R is an acetyl group or a halogen group.

[0105] A particularly preferred R-substituted aromatic thioether triarylsulfonium tetrakis(pentafluorophenyl)borate cationic photoinitiator is tris(4-(4-acetylphenyl)phenylthio)sulfonium tetrakis(pentafluorophenyl)borate. Tris(4-(4-acetylphenyl)phenylthio)sulfonium tetrakis(pentafluorophenyl)borate is commercially available as PAG-290 is known (formerly known under the development code GSID 4480-1) and is available from Ciba / BASF.

[0106] R-substituted aromatic thioether triarylsulfonium tetrakis(pentafluorophenyl)borate cationic photoinitiators (e.g., tris(4-(4-acetylphenyl)phenylthio)sulfonium tetrakis(pentafluorophenyl)borate) are also more thermally stable than some other cationic photoinitiators. The improved thermal stability allows radiation-curable compositions for addition manufacturing that incorporate triarylsulfonium tetrakis(pentafluorophenyl)borate cationic photoinitiators in place of other conventional cationic photoinitiators to maintain their viscosity at elevated temperatures for extended periods of time.

[0107] In another embodiment, the cationic photoinitiator is an aromatic triarylsulfonium salt having a structure consisting of SbF6 - PF6 - 、BF4 - 、(CF3CF2)3PF3 - 、(C6F5)4B - 、((CF3)2C6H3)4B - 、(C6F5)4Ga - 、((CF3)2C6H3)4Ga - , trifluoromethanesulfonate, nonafluorobutanesulfonate, methanesulfonate, butanesulfonate, benzenesulfonate, or p-toluenesulfonate and a cation of the following formula (II):

[0108]

[0109] Wherein in formula (II), R 1 、R 2 、R 3 、R 5 and R 6each independently represents an alkyl group, a hydroxyl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic hydrocarbon group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, or a halogen atom, and R 4 represents an alkyl group, a hydroxyl group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an acyloxy group, an alkylthio group, a heterocyclic hydrocarbon group, an alkylsulfinyl group, an alkylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, or a halogen atom, m 1 to m 6 Each represents R 1 to R 6 The number of times each of them appears, m 1 、m 4 and m 6 Each represents an integer from 0 to 5, m 2 、m 3 and m 5 Each represents an integer from 0 to 4. Such photoinitiators are described, for example, in US Pat. No. 8,617,787.

[0110] Particularly preferred aromatic triarylsulfonium cationic photoinitiators have an anion that is a fluoroalkyl substituted fluorophosphate. Commercial examples of aromatic triarylsulfonium cationic photoinitiators having a fluoroalkyl substituted fluorophosphate anion are the CPI-200 series available from San-Apro Limited (e.g. or ).

[0111] According to some embodiments of the present invention, in addition to R substituted aromatic sulfide triarylsulfonium tetrakis (pentafluorophenyl) borate cationic photoinitiator or fluoroalkyl substituted fluorophosphate cationic photoinitiator, the radiation curable composition for addition manufacturing further comprises a cationic polymerizable component. In other embodiments, the radiation curable composition for addition manufacturing includes a cationic polymerizable component, a free radical photoinitiator and a free radical polymerizable component. In some embodiments, the radiation curable composition for addition manufacturing includes R substituted aromatic sulfide triarylsulfonium tetrakis (pentafluorophenyl) borate cationic photoinitiator and another cationic photoinitiator and / or photosensitizer, as well as a cationic polymerizable component and optionally a free radical polymerizable component and a free radical photoinitiator.

[0112] The radiation curable composition may include any suitable amount of cationic photoinitiator, for example, in an amount of up to about 15% by weight of the composition in certain embodiments, in an amount of up to about 5% by weight of the composition in certain embodiments, and in an amount of from about 2% to about 10% by weight of the composition in other embodiments, and in an amount of from about 0.1% to about 5% by weight of the composition in other embodiments. In another embodiment, the amount of cationic photoinitiator is from about 0.2% to about 4% by weight of the total composition, and in other embodiments, from about 0.5% to about 3% by weight.

[0113] In some embodiments, depending on the wavelength of light used to cure the radiation-curable composition, it is desirable that the radiation-curable composition include a photosensitizer. The term "photosensitizer" is used to refer to any substance that increases the rate of photoinitiated polymerization or shifts the wavelength at which polymerization occurs; see G. Odian's textbook, Principles of Polymerization, 3rd edition, 1991, page 222. A variety of compounds can be used as photosensitizers, including heterocyclic and fused-ring aromatic hydrocarbons, organic dyes, and aromatic ketones. Examples of photosensitizers include those selected from the group consisting of ketones, xanthone, pyrene methanol, anthracene, pyrene, perylene, quinone, xanthone, thioxanthone, benzoyl esters, benzophenone, and any combination thereof. Specific examples of the photosensitizer include those selected from the group consisting of [4-[(4-methylphenyl)thio]phenyl]phenyl-methanone, isopropyl-9H-thioxanthen-9-one, 1-pyrene methanol, 9-(hydroxymethyl)anthracene, 9,10-diethoxyanthracene, 9,10-dimethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, 9-anthracene methanol acetate, 2-ethyl-9,10-dimethoxyanthracene, 2-methyl-9,10-dimethoxyanthracene, and combinations thereof.

[0114] The novel mixture may also contain various photoinitiators with varying sensitivities to radiation of different wavelengths to achieve better utilization of the UV light source. The use of known photoinitiators with varying sensitivities to radiation of different wavelengths is well known in the art of additive manufacturing and can be selected based on, for example, the radiation source of 351 nm, 355 nm, 365 nm, 385 nm, and 405 nm. In this case, it is advantageous to select the various photoinitiators and use them in concentrations that result in equivalent light absorption with the radiation used.

[0115] Radiation curable compositions for additive manufacturing may include any suitable amount of photosensitizer, such as in certain embodiments in an amount up to about 10% by weight of the composition, in certain embodiments in an amount up to about 5% by weight of the composition, and in other embodiments in an amount from about 0.05% to about 2% by weight of the composition.

[0116] Free radical photoinitiators

[0117] Typically, free radical photoinitiators are divided into free radical initiators (known as "Norrish I type") that form free radicals by cracking and free radical initiators (known as "Norrish II type") that form free radicals by abstracting hydrogen. Norrish II type photoinitiators require a hydrogen donor, which acts as a source of free radicals. Because initiation is based on a bimolecular reaction, Norrish II type photoinitiators are typically slower than Norrish I type photoinitiators based on the unimolecular formation of free radicals. On the other hand, Norrish II type photoinitiators have better light absorption characteristics in the near-UV spectral region. The photolysis of aromatic ketones (such as benzophenone, thioxanthone, benzil and quinone) in the presence of a hydrogen donor (such as an alcohol, an amine or a thiol) leads to the formation of free radicals (ketyl-type radicals) generated by carbonyl compounds and another free radical derived from the hydrogen donor. The photopolymerization of vinyl monomers is typically initiated by free radicals generated from hydrogen donors. Ketyl groups are generally unreactive toward vinyl monomers due to steric hindrance and delocalization of the unpaired electron.

[0118] In order to successfully formulate radiation curable compositions for additive manufacturing, it is necessary to examine the wavelength sensitivity of the photoinitiator or photoinitiators present in the composition to determine whether they will be activated by the radiation source selected to provide the curing light.

[0119] According to one embodiment, the radiation curable composition for additive manufacturing comprises at least one free radical photoinitiator, such as those selected from the group consisting of benzoylphosphine oxide, aryl ketones, benzophenones, hydroxylated ketones, 1-hydroxyphenyl ketones, ketals, metallocenes, and any combination thereof.

[0120] In one embodiment, the radiation curable composition for additive manufacturing comprises at least one free radical photoinitiator selected from the group consisting of 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1, 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholino)phenyl]-1-butanone, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholino-4-yl-phenyl)-butan-1-one, 4-benzoyl-4'-methyldiphenyl sulfide, 4,4'-bis(diethylamino)benzophenone, and 4,4'-bis(diethylamino)benzophenone. 4'-bis(N,N'-dimethylamino)benzophenone (Michler's ketone), benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, dimethoxybenzophenone, 1-hydroxycyclohexylphenyl ketone, phenyl(1-hydroxyisopropyl)ketone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, 4-isopropylphenyl(1-hydroxyisopropyl)ketone, oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], camphorquinone, 4,4'-bis(diethylamino)benzophenone, benzildimethylketal, bis(η5-2-4-cyclopentadien-1-yl)bis[2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl]titanium, and any combination thereof.

[0121] For light sources emitting in the wavelength range of 300-475 nm, especially those emitting at 365 nm, 390 nm or 395 nm, examples of suitable free radical photoinitiators that absorb in this region include: benzoylphosphine oxides, such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO from BASF) and 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide (Lucirin TPO-L from BASF), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819 or BAPO from Ciba), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1 (Irgacure 907 from Ciba), 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholino)phenyl]-1-butanone (Irgacure 1000 from Ciba), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1 (Irgacure 1001 from Ciba), 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholino)phenyl]-1-butanone (Irgacure 1001 from Ciba), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1 (Irgacure 1001 from Ciba), 2-methyl-1-[4-(4-morpholino)phenyl]-1-butanone (Irgacure 1001 from Ciba), 2-methyl-1-[4-(4-morpholino)phenyl]-2-morpholinopropanone-1 (Irgacure 1001 from Ciba), 2-methyl-1-[4-(4-morpholino)phenyl]-2-morpholinopropanone-1 Suitable examples include 2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (Irgacure 369 from Ciba), 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (Irgacure 379 from Ciba), 4-benzoyl-4'-methyldiphenyl sulfide (Chivacure BMS from Chitec), 4,4'-bis(diethylamino)benzophenone (Chivacure EMK from Chitec), and 4,4'-bis(N,N'-dimethylamino)benzophenone (Michler's ketone). Mixtures thereof are also suitable.

[0122] In addition, photosensitizers can be used in combination with photoinitiators to achieve curing with LED light sources emitting in this wavelength range. Examples of suitable photosensitizers include: anthraquinones, such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, and 2-amylanthraquinone; thioxanthones and xanthones, such as isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and 1-chloro-4-propoxythioxanthone; methyl benzoyl formate (Darocur MBF from Ciba); methyl-2-benzoyl benzoate (Chivacure OMB from Chitec); 4-benzoyl-4'-methyldiphenyl sulfide (Chivacure BMS from Chitec); 4,4'-bis(diethylamino)benzophenone (Chivacure EMK from Chitec).

[0123] It is possible to design a UV radiation source to emit light at shorter wavelengths. For light sources emitting at wavelengths between about 100 nm and about 300 nm, it is possible to employ a photosensitizer and a photoinitiator. When a photosensitizer (such as those listed above) is present in the formulation, other photoinitiators that absorb at shorter wavelengths may be used. Examples of such photoinitiators include: benzophenones, such as benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, dimethoxybenzophenone; and 1-hydroxyphenyl ketones, such as 1-hydroxycyclohexylphenyl ketone, phenyl(1-hydroxyisopropyl)ketone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone and 4-isopropylphenyl(1-hydroxyisopropyl)ketone; benzil dimethyl ketal and oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] (Esacure KIP 150 from Lamberti).

[0124] The radiation source can also be designed to emit at higher wavelengths. For radiation sources emitting light at wavelengths between about 475 nm and about 900 nm, examples of suitable free radical photoinitiators include camphorquinone, 4,4'-bis(diethylamino)benzophenone (Chivacure EMK from Chitec), 4,4'-bis(N,N'-dimethylamino)benzophenone (Michler's ketone), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide ("BAPO", or Irgacure 819 from Ciba), metallocenes such as bis(η5-2-4-cyclopentadien-1-yl)bis[2,6-difluoro-3(1H-pyrrol-1-yl)phenyl]titanium (Irgacure 784 from Ciba), and visible light photoinitiators such as H-Nu from Spectra Group Limited, Inc. 470, H-Nu-535, H-Nu-635, H-Nu-Blue-640 and H-Nu-Blue-660.

[0125] In one embodiment of the claimed invention, the light emitted by the radiation source is UVA radiation, which is radiation having a wavelength between about 320 nm and about 400 nm. In one embodiment of the claimed invention, the light emitted by the radiation source is UVB radiation, which is radiation having a wavelength between about 280 nm and about 320 nm. In one embodiment of the claimed invention, the light emitted by the radiation source is UVC radiation, which is radiation having a wavelength between about 100 nm and about 280 nm.

[0126] The radiation curable compositions for additive manufacturing may include any suitable amount of a free radical photoinitiator as component (d), such as in certain embodiments in an amount up to about 10% by weight of the composition, in certain embodiments in an amount from about 0.1% to about 10% by weight of the composition, and in other embodiments in an amount from about 1% to about 6% by weight of the composition.

[0127] filler

[0128] The liquid radiation-curable composition for additive manufacturing according to the present invention also preferably comprises at least one filler. Inorganic substances are particularly preferred as fillers because they tend to impart water resistance, heat resistance, and robust mechanical properties to the cured solid three-dimensional parts produced therefrom. In one embodiment, the radiation-curable composition for additive manufacturing according to the present invention consists of or consists essentially of an inorganic filler.

[0129] In one embodiment, fillers whose particles are spherical, defined herein as having a sphericity of 0.80 or greater, are used due to the particles' ability to maintain a lower viscosity of the composition and the improved molding characteristics and enhanced accuracy they impart to three-dimensional objects made from the compositions prepared according to the invention.

[0130] In one embodiment of the invention, the filler is inorganic and comprises, is made up of or is substantially made up of ceramics, and the ceramics are such as silicon dioxide (SiO 2 ) nanoparticles, i.e., those particles having an average particle size between 1 nanometer (nm) and 999 nm, or between 5 nm and 999 nm, or between 10 nm and 999 nm. In one embodiment, the filler is inorganic and comprises, is made up of or is substantially made up of silicon dioxide particles, i.e., those particles having an average particle size between 1 micron (μm) and 999 μm, or between 1 μm and 800 μm, or between 1 μm and 500 μm, or between 1 μm and 100 μm. In a preferred embodiment, the filler is made up of inorganic microparticles and / or nanoparticles, such as silicon dioxide microparticles and / or silicon dioxide nanoparticles. Average particle size can be measured according to ISO 13320:2009 using laser diffraction particle size analysis. Those skilled in the art to which the present invention applies will understand the specific equipment and conditions required for measuring particles below 0.1 μm according to such standards. A suitable device for measuring the average particle size of nanoparticles is the LB-550 machine available from Horiba Instruments, Inc., which measures particle size by dynamic light scattering.

[0131] The nanoparticles or microparticles may be a powder that is essentially based on silicon dioxide, for example greater than 85 wt%, more preferably 90 wt%, more preferably 95 wt% silicon dioxide (SiO2). Some non-limiting examples of commercially available silica powder products include Crystallite 3K-S, Crystallite NX-7, Crystallite MCC-4, Crystallite CMC-12, Crystallite A-1, Crystallite AA, Crystallite C, Crystallite D, Crystallite CMC-1, Crystallite C-66, Crystallite 5X, Crystallite 2A-2, Crystallite VX-S2, Crystallite VX-SR, Crystallite VX-X, Crystallite VX-S, HUSELEX RD-8, HUSELEX RD-120, HUSELEX MCF-4, HUSELEX GP-200T, HUSELEX ZA-30, HUSELEX RD-8, HUSELEX Y-40, HUSELEX E-2, HUSELEX Y-60, HUSELEX E-1, HUSELEX E-2, HUSELEX FF, HUSELEX TM MEK-EC-2102、ORGANOSILICASOL TM MEK-EC-2104、ORGANOSILICASOL TM MEK-AC-2202、ORGANOSILICASOL TM MEK-AC-4101、ORGANOSILICASOL TM MEK-AC-5101、ORGANOSILICASOL TM MIBK-SD、ORGANOSILICASOL TM MIBK-SD-L、ORGANOSILICASOL TM DMAC-ST、ORGANOSILICASOL TM EG-ST、ORGANOSILICASOL TM IPA-ST、ORGANOSILICASOLTM IPA-ST-L、ORGANOSILICASOL TM IPA-ST-L-UP、ORGANOSILICASOL TM IPA-ST-ZL、ORGANOSILICASOL TM MA-ST-M、ORGANOSILICASOL TM MEK-ST、ORGANOSILICASOL TM MEK-ST-L、ORGANOSILICASOL TM MEK-ST-UP、ORGANOSILICASOL TM MIBK-ST、ORGANOSILICASOL TM MT-ST、ORGANOSILICASOL TM NPC-ST-30、ORGANOSILICASOL TMSUNSPHERE NP-100 and SUNSPHERE NP-200 (AsahiGlass Co., Ltd.); Silstar MK-08 and MK-15 (Nippon Chemical Industrial Co., Ltd.); FB-48 (Denki Kagaku Kogyo KK); Nipsil SS-10, Nipsil SS-15, Nipsil SS-10A, Nipsil SS-20, Nipsil SS-30P, Nipsil Nipsil Nipsil HD-2, Nipsil N-300A, Nipsil L-250, Nipsil G-300, Nipsil E-75, Nipsil E-743, and Nipsil E-74P (Nippon Silica Industry, Ltd.) See U.S. Patent 6,013,714 for other examples of silica particles.

[0132] In other embodiments of the present invention, alternative inorganic filler materials, such as those containing glass or metal particles, may be used. Some non-limiting examples of such materials include: glass powder, aluminum oxide, hydrated aluminum oxide, magnesium oxide, magnesium hydroxide, barium sulfate, calcium sulfate, calcium carbonate, magnesium carbonate, silicate minerals, diatomaceous earth, silica sand, silica powder, titanium oxide, aluminum powder, bronze, zinc powder, copper powder, lead powder, gold powder, silver powder, glass fiber, potassium titanate whiskers, carbon whiskers, sapphire whiskers, verification rear whiskers, boron carbide whiskers, silicon carbide whiskers, and silicon nitride whiskers.

[0133] Some non-limiting examples of such other commercially available inorganic filler products include glass beads GB210, GB210A, GB210B, GB210C, GB045Z, GB045ZA, GB045ZB, GB045ZC, GB731, GB731A, GB731B, GB731C, GB731M, GB301S, EGB210, EGB210A, EGB210B, EGB2 10C, EGB045Z, EGB045ZA, EGB045ZB, EGB045ZC, MB-10, MB-20, EMB-10, EMB-20, HSC070Q, HSC-024X, HSC-080S, HSC-070G, HSC-075L, HSC-110, HSC-110A, HSC-110B, and HSC-110C (Toshiba Balotini Co., Ltd.); sodium zeolite #100, sodium zeolite Fine Flow B, sodium zeolite Fine Flow A, sodium zeolite Sparkle Flow, sodium zeolite Special Flow, sodium zeolite #300, sodium zeolite #200, sodium zeolite Clear Flow, sodium zeolite #500, sodium zeolite #600, sodium zeolite #2000, sodium zeolite #700, sodium zeolite #500S, sodium zeolite #800, sodium zeolite #900, sodium zeolite #800S, sodium zeolite #3000, sodium zeolite Ace, sodium zeolite Superace, sodium zeolite High Ace, sodium zeolite PC-1, sodium zeolite Delux P-5, sodium zeolite DeluxW50, sodium zeolite Microfine, sodium zeolite F, sodium zeolite SPF, sodium zeolite GC, Topco#31, Topco#34, Topco#36, Topco#38, and Topco#54 (Showa Chemical Industry Co., Ltd.); Higilite HX, HigiliteH-21, Higilite H-31, Higilite H-32, Higilite H-42, Higilite H-42M, Higilite H-43, Higilite H-32ST, Higilite H-42STV, Higilite H-42T, Higilite H-34, Higilite H-34HL, Higilite H-32I, Higilite Higilite HS-341, alumina A-426, alumina A-42-1, alumina A-42-2, alumina A-42-3, alumina A-420, alumina A-43M, alumina A-43-L, alumina A-50-K, alumina A-50-N, alumina A-50-F, alumina AL-45-H, alumina AL-45-2, alumina AL-45-1, alumina AL-43-M, alumina AL-43-L, alumina AL-43PC, alumina AL-150SG, alumina AL-170, alumina A-172, alumina A-173, alumina AS10, alumina AS-20, alumina AS-30, alumina AS-40, and alumina AS-50 (Showa Denko KK); Starmague U, Starmague M, Starmague L, Starmague P, Starmague C, Starmague CX, high-purity magnesia HP-10, high-purity magnesia HP-10N, high-purity magnesia HP-30, Star-200, Star-10, Star-10A, Star magnesium carbonate Venus, Star two-star magnesium carbonate, Star one-star magnesium carbonate, Star magnesium carbonate S, Star magnesium carbonate Fodder, Star heavy magnesium carbonate, high-purity magnesium carbonate GP-10, high-purity magnesium carbonate 30, Star general-purpose light calcium carbonate, Star light calcium carbonate EC, and Star light calcium carbonate KFW-200 (Konoshima Chemical Industry Co., Ltd.); MKC silica GS50Z and MKC silica SS-15 (Mitsubishi Chemical Corp.), AdmafineSOE-E3、Admafine SO-C3、Admafine AO-800、Admafine AO-809、Admafine AO-500、Admafine AO-509(Adomatex Co., Ltd.); MSGEL D-560A、MSGEL D-5120A、MSGEL D-5300A、MSGEL D-2060A、MSGEL D-20120A、MSGEL D-20-300A、SILDE-X H-31、SELDEXH-32、SILDEX H-51、SILDEX H-52、SILDEX H-121、SILDEX H-122、SILDEX L-31、SILDEX L-51、SILDEX L-121、SILD EX F-51、SILDEX F-121(Asahi Glass); SILDEX 250、SILDEX 250N、SILIA 256、SILIA 256N、SILISIA 310、SILISIA 320、SILISIA 350、SILISIA 358、SILISIA 430、SILISIA 431、SILISIA 440、SILISIA 450、SILISIA 470、SILISIA 435、SILISIA 445、SILISIA 436、SILISIA 446、SILISIA 456、SILISIA 530、SILISIA 540、SILISIA 550、SILISIA 730、SILISIA 740、SILISIA 770、SYLOPHOBIC100、SYLOPHOBIC 200(Fuji Silysia Chemical Co., Ltd.); and Tismo-D、Tismo-L、ToficaY、Tofica YN、Tofica YB、Dendol WK-200、Dendol WK-200B、Dendol WK-300, Dendol BK-200, Dendol BK-300, Swanite, and Barihigh B Super Dendol (Otsuka Chemical Co., Ltd.).

[0134] The inorganic filler may also be surface-treated with a silane coupling agent. Silane coupling agents useful for this purpose include vinyltrichlorosilane, vinyltri(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-(methacryloyloxypropyl)trimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycyloxypropyltrimethoxysilane, γ-glycyloxypropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane. It is known in the art to which the present invention pertains that surface treatment of particles improves their resin / matrix compatibility.

[0135] The surface condition of the filler particles used, as well as impurities contained in the filler from the manufacturing process, can affect the curing reaction of the composition. In such cases, it is preferred to wash the filler particles or coat the particles with a suitable primer as a method of improving the curing characteristics. The inventors have also noted that certain fillers tend to cause a particularly significant decrease in viscosity stability. Without wishing to be bound by any particular theory, the presumed cause of this phenomenon is the presence of residual acid in the particles of such fillers, which is an undesirable but often unavoidable byproduct of the manufacturing process used to create the filler. This residual acid will react with the cationic polymerizable components in the surrounding resin, resulting in partial polymerization and an increase in viscosity over time.

[0136] The radiation curable composition for additive manufacturing can include any suitable amount of inorganic filler or a combination of fillers as component (e), such as the amount of the component (e) is at most about 80 wt % of the total composition, in certain embodiments, about 30 wt % to about 80 wt % of the composition, and in other embodiments, about 50 wt % to about 70 wt % of the composition. If the amount of component (e) is too little, the water resistance and heat resistance, durability and structural rigidity of the mold made from the prepared composition will not fully increase. On the other hand, if the amount of component (e) is too large, the fluidity of the prepared composition becomes too low, thereby making it difficult to operate in additive manufacturing process, or even inoperable. Excessive component (e) can also affect the time required for radiation curing of the composition, thereby causing the processing time to increase significantly.

[0137] Light absorbing components

[0138] As used herein, "light absorbing components" include those components that are added to a formulation to increase the amount of light absorbed by the overall composition at a certain wavelength and that have not been characterized as photoinitiators or photosensitizers.

[0139] The inventors have found a variety of technical methods for reducing the surface reflection of high-intensity lasers directed at the cured objects produced by the composition according to the present invention. Each of these methods is partially focused on adjusting the composition so that it maximizes the amount of light absorbed at one or more wavelengths of the laser-emitted radiation in a specific PIV test. In an embodiment where a "green" laser emits radiation at a peak intensity of 532nm, the composition used therewith will therefore have an absorbance maximized at this wavelength. By tuning a composition that can absorb significantly at the wavelength of light at which the laser in the PIV test works ("PIV wavelength" or "first wavelength"), the parts created by the composition will tend to reduce the surface reflection in the PIV test to a level sufficient to achieve accurate data collection at a position very close to the surface of the part. Many different types of colorant additives can be added to the composition to tune whether to increase absorption at a specific wavelength. Known feasible additives also include pigments, laser dyes (or visible light absorbers) and photochemical latent dyes.

[0140] However, the radiation curable compositions of the present invention must also be suitable for use in various additive manufacturing build processes. Thus, not all light absorbing components that would otherwise reduce absorption at PIV wavelengths can be utilized in the present invention, as such components may also limit the ability of the composition to polymerize at one or more wavelengths ("AF wavelengths" or "second wavelengths") at which the additive manufacturing build process is performed. Black pigments, dyes, or other fillers absorb effectively at PIV wavelengths, but also tend to block all UV-visible light (including AF wavelengths), and therefore should be avoided in amounts sufficient to prevent curing in the additive manufacturing process itself.

[0141] Thus, in a preferred embodiment, the one or more light absorbing components should meet the following criteria: (1) strong absorption at a first wavelength, and (2) low or zero fluorescence emission at the first wavelength; (3) low or no absorption at a second wavelength; and (4) no other tendency to inhibit or reduce the cure rate of the associated radiation curable composition. Even if all other criteria are met (including minimal absorption at the second wavelength), an additive with very strong basicity that may inhibit or kill the photoacid species necessary for the cationic polymerization mechanism may not meet the fourth criterion.

[0142] In a preferred embodiment, any suitable light absorber, including inorganic pigments, photochemically latent dyes, and / or laser dyes that meet the above criteria, may be incorporated into the compositions of the present invention. The specific identity of the light absorber(s) used will depend on the AF and PIV wavelengths associated with the composition (or part cured from the composition).

[0143] Dyes that may be used include Leuco dyes, which are described in US Pat. No. 6,031,021 and in columns 52 and 53 of US Pat. No. 5,470,816, the entire contents of each of which, in relevant part, are hereby incorporated by reference.Specific examples of such dyes include (1) Leuco bases of triphenylmethane dyes such as 3,3-bis(p-dimethylaminophenyl)phthalide, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (or crystal violet lactone), 3,3-bis(p-dimethylaminophenyl)-6-diethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)-6-chlorophthalide, and 3,3-bis(p-dibutylaminophenyl)phthalide; and (2) Leuco bases of fluoran dyes such as 3-cyclohexylamino-6-chlorofluoran, 3-(N,N-diethylamino)-5-methyl-7-(N,N-dibenzylamino)fluoran, 3-dimethylamino-5,7-dimethylfluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-5-methyl-7-tert-butylfluoran; (3) fluoran dyes, for example 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-pyrrolidinyl-6-methyl-7-chlorofluoran, 3-dimethylamino-6-methyl-7-anilinofluoran, 2-(N-(3'-trifluoromethylphenyl)amino)-6-diethylamino-fluoran, 3-diethylamino-7-cyclohexylaminofluoran, 2-(3,6-bis(diethylamino)-9-(o-chloroanilino)xanthenyl-benzoic acid lactam), 3-dimethylamino-6-methyl-7-p-butylanilinofluoran, 3- Diethylamino-6-methyl-7-anilinofluoran, 3-(N-ethyl-p-toluidinyl)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isopentylamino)-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(o,p-dimethylanilino)fluoran, 3-pyrrolidinyl-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluoran, 3-diethylamino-7-(m-trifluoromethylanilino)fluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6 (4) lactone compounds such as 3-(2'-hydroxy-4-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl)phthalide, 3-(2'-hydroxy-4-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)phthalide, and 3-(2'-hydroxy-4-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl)phthalide. Suitable commercial examples of this type include: Series of dyes.

[0144] For compositions with a PIV wavelength of 532 nm and an AF wavelength of 355 nm (wavelengths employed in many stereolithography applications), several specific examples of light absorbers can be used, including Lisso Red dispersions, photochemically latent dyes (e.g., Copikem Magenta), and laser dyes (e.g., Rhodamine 6G), as well as combinations thereof.

[0145] In one embodiment, the light absorbing component comprises a compound defined by the following formula (III):

[0146]

[0147] wherein R1, R2, R3, R4, R5, and R6 each independently represent a hydrogen atom, a substituted methyl or alkyl group, or an unsubstituted methyl or alkyl group; and R7 represents an unsubstituted phenyl group or a substituted phenyl group. In a preferred embodiment, R7 represents a benzoate group. In this case, the compound defined by formula (III) is referred to as fluorescein or rhodamine. The specific identity of the methyl or alkyl substituents R1, R2, R3, R4, R5, and R6 can be adjusted as desired, as such substituents are not expected to have a significant effect on the optical properties or absorbance of the dye to which they are associated.

[0148] In a preferred embodiment, the light absorbing component comprises a xanthene or rhodamine dye. Rhodamine dyes are known and are described, inter alia, in US 3708499, US 3767358, and US 3849065, each of which is hereby incorporated by reference in its entirety. A non-limiting list of commercially available dyes of this type includes rhodamine 110, rhodamine 6G, and rhodamine B. Such dyes have the following molecular structure:

[0149]

[0150] The inventors have discovered that while several known dyes, pigments, and other light absorbers described herein can be effectively used to impart sufficiently high desired absorbance values at certain wavelengths of light used in particle imaging velocimetry testing, they similarly impart abnormally high absorbance at the wavelengths of light used in the additive manufacturing process required to convert them into test parts. Due to this generally high absorbance, light of all wavelengths—including those required to initiate the polymerization process—can be prevented from penetrating the resin to a sufficient depth. This has the effect of increasing the build time required for additive manufacturing by necessitating lower machine scan speeds, smaller layer thicknesses, or both. In extreme cases, compositions with excessive absorbance values (at least at the relevant curing wavelengths) will be completely incapable of creating three-dimensional parts via additive manufacturing processes. Of course, the absorbance at the wavelength or wavelengths used in the additive manufacturing process cannot be too low, as in this case the material will not polymerize at all or will not produce a cured object at all. The inventors have surprisingly discovered that light absorbing components can be synthesized and tailored such that radiation curable compositions incorporating the light absorbing components are simultaneously specifically tailored and optimized to: (1) maximize the absorbance of three-dimensional parts cured from the radiation curable compositions at the wavelength of light used in PIV testing, (2) limit the absorbance of the liquid radiation curable composition at the wavelength of light used in the additive manufacturing process itself, and (3) limit the "cooling" effect of cationic polymerization by increasing the acidity.

[0151] In one embodiment, the composition is configured so that it (or alternatively a test part cured therefrom) has an absorbance of at least 10, or at least 15, or at least 20, or at least 25, or at least 30, or 10-1000, or 15-500, or 20-200, or 25-150, or 30-100, or 30-80, or 35-75 at the wavelength at which the light source in the particle imaging velocimetry test operates.

[0152] In one embodiment, the composition is further formulated such that it (or alternatively a test part cured therefrom) has an absorbance of less than 100, or less than 80, or less than 60, or less than 50, or less than 45, or at least 25, or at least 35, or at least 39, or 25-100, or 25-80, or 25-60, or 25-50, or 25-45, or 35-100, or 35-80, or 35-60, or 35-45, or 35-50, or 39-100, or 39-80, or 39-60, or 39-50, or 39-45 at the wavelength at which the light source in the additive manufacturing process operates.

[0153] In a preferred embodiment, the composition (or alternatively a cured test part thereof) is further configured such that the difference in absorbance between the peak wavelength at which the light source in the particle imaging velocimetry test operates and the peak wavelength at which the light source in the additive manufacturing process operates is greater than -50, or greater than -40, or greater than -30, or greater than -20, or greater than -10, or greater than 0, or greater than 10, or greater than 20, or greater than 30, or greater than 50, or greater than 100, or greater than 150, or less than 200, or less than 150, or less than 100, or less than 50, or less than 30, or less than 20, or less than 10, or less than 0, or less than -10, or less than -20, or about -50 to 200, or about -40 to 200, or about -30 or about -20 to about 100, or about -30 to about 80, or about -30 to about 60, or about -30 to about 30, or about -30 to about 20, or about -30 to about 10, or about -30 to about 0, or about -30 to about -10, or about -20 to about 100, or about -20 to about 80, or about -20 to about 60, or about -20 to about 30, or about -20 to about 20, or about -20 to about 10, or about -20 to about 0, or about -20 to about -10, or about -10 to about 100, or about -10 to about 80, or about -10 to about 60, or about -10 to about 30, or about -10 to about 20, or about -10 to about 10, or about -10 to about 0.

[0154] In other preferred embodiments, the composition (or alternatively a test part cured therefrom) is further configured such that the absorbance difference between the peak wavelength at which the light source in the particle imaging velocimetry test operates and the peak wavelength at which the light source in the additive manufacturing process operates is between 0 and 150, or between 0 and 100, or between 0 and 50, or between 0 and 30, or between 10 and 150, or between 10 and 100, or between 10 and 50, or between 20 and 200, or between 20 and 100, or between 20 and 50.

[0155] Thus, in one embodiment, the composition comprises a light absorbing component that is modified to maximize absorbance at the wavelength to be used in the PIV test and to minimize absorbance at the wavelength used in the additive manufacturing process. In a preferred embodiment, particularly where the additive manufacturing process is performed using a conventional additive manufacturing light source that imparts radiation at 355 nm or 365 nm and the PIV test is performed using a laser that emits 532 nm light, the light absorber is a fluorine antimony modified compound. This compound is distinguished from related cationic photoinitiators, which are typically fluorine antimony based in such additive processes that incorporate cationic polymerizable components. In one embodiment, the fluorine antimony modified compound is an SbF6 modified pigment, an SbF6 modified laser dye, or a triarylmethane cationic dye.

[0156] In one embodiment, the light absorbing component comprises a compound defined by the following formula (IV):

[0157]

[0158] in

[0159] X and X' represent Cl – Br – , I – 、SO4 2– 、NO3 – 、ClO4 – 、AsF6 – 、SbF6 – PF6 – 、BF4 – 、(CF3CF2)3PF3 – 、(C6F5)4B – 、((CF3)2C6H3)4B – 、(C6F5)4Ga – 、((CF3)2C6H3)4Ga – , trifluoromethanesulfonate, nonafluorobutanesulfonate, methanesulfonate, butanesulfonate, benzenesulfonate, or p-toluenesulfonate;

[0160] R1, R2, R3, R4, R5 and R6 each independently represent a hydrogen atom, a substituted methyl or alkyl group, or an unsubstituted methyl or alkyl group; and

[0161] R7 represents a hydrogen atom, an unsubstituted phenyl group, or a substituted phenyl group.

[0162] In one embodiment, X or X' of formula (IV) represents Cl – Br – , I – 、SO42– 、NO3 – 、ClO4 – 、AsF6 – 、SbF6 – or PF6 – , and preferably antimony hexafluoride (SbF6) - ion.

[0163] X or X' according to formula (IV) can be adjusted to match the anion of the attached cationic photoinitiator. It is believed that matching the ion of the cationic photoinitiator with the modified light absorbing component helps to achieve fast curing at the wavelength of the addition manufacturing process. Therefore, in one embodiment, the anion of the cationic photoinitiator is also represented by X or X' according to formula (IV).

[0164] The light absorbing components listed above can be used alone or in combinations of two or more. The radiation curable compositions for addition manufacturing can contain any suitable amount or combination of the light absorbing components listed above, for example, in an amount of up to about 25% by weight, or up to about 10% by weight, or up to about 5% by weight, or greater than 0.005% by weight, or greater than 0.01% by weight, or greater than 0.1% by weight, or greater than 0.5% by weight, or greater than 1% by weight, or from 0.005% to about 5% by weight, or from 0.01% to about 5% by weight, or from 0.005% to about 0.5% by weight, relative to the weight of the entire composition.

[0165] Stabilizers and other additives

[0166] Stabilizers are typically added to the composition to further prevent viscosity buildup, such as during use in solid imaging processes. Useful stabilizers include those described in U.S. Patent No. 5,665,792, the entire disclosure of which is hereby incorporated by reference. In the present invention, the presence of a stabilizer is optional. In a specific embodiment, the radiation-curable composition for additive manufacturing comprises from 0.1% to 3% by weight of a stabilizer.

[0167] If present, such stabilizers are typically hydrocarbon carboxylates of Group IA and Group IIA metals. The most preferred examples of these salts are sodium bicarbonate, potassium bicarbonate, and rubidium carbonate. Solid stabilizers are generally not preferred in filled compositions. If present, 15-23% sodium carbonate solution is preferred for the formulations of the present invention, with recommended amounts varying between 0.05-3.0% by weight of the composition, more preferably 0.05% to 1.0% by weight, and more preferably 0.1% to 0.5% by weight of the composition. Alternative stabilizers include polyvinyl pyrrolidone and polyacrylonitrile.

[0168] Other possible additives include dyes, pigments, antioxidants, wetting agents, photosensitizers for free radical photoinitiators, chain transfer agents, leveling agents, defoamers, surfactants, and the like.

[0169] The radiation curable composition for additive manufacturing of the present invention may further comprise one or more additives selected from the group consisting of defoamers, antioxidants, surfactants, acid scavengers, pigments, dyes, thickeners, flame retardants, silane coupling agents, ultraviolet absorbers, resin particles, core-shell particle impact modifiers, soluble polymers and block polymers.

[0170] To be effective in wind tunnel applications, in one embodiment, the filled compositions are capable of imparting sufficient strength and stiffness to the three-dimensional solid objects they form upon curing. Thus, it is preferred that the liquid radiation-curable compositions for additive manufacturing according to the present invention have a tensile modulus of at least 6,000 MPa, more preferably at least about 8,000 MPa, and even more preferably at least about 10,000 MPa, after full curing with actinic radiation and 60 minutes of UV and thermal post-curing according to methods well known in the art of additive manufacturing and stereolithography (ASTM D638-14). In one embodiment of the present invention, the tensile modulus achieved is between about 8,000 MPa and about 12,000 MPa.

[0171] In addition, even after exposure to high heat conditions, the filled compositions must be able to impart sufficient elasticity and integrity to the three-dimensional solid objects they form when cured. Therefore, it is preferred that the liquid radiation-curable compositions for additive manufacturing according to the present invention have a heat distortion temperature of at least about 80 degrees Celsius, more preferably at least about 100 degrees Celsius, and more preferably at least about 110 degrees Celsius at 1.82 MPa after full cure with actinic radiation and 60 minutes of UV and thermal post-curing according to methods well known in the art of additive manufacturing and stereolithography (ASTM D648-16). In one embodiment of the invention, the heat distortion temperature at 1.82 MPa is between about 80 degrees Celsius and about 120 degrees Celsius.

[0172] A fourth aspect of the claimed invention is a three-dimensional object formed from the radiation curable composition of any of the first three aspects of the invention by any of the methods described or claimed herein.

[0173] The following examples further illustrate the present invention but, of course, should not be construed as limiting the scope of the invention in any way.

[0174] Example

[0175] These examples illustrate embodiments of the additively manufactured radiation curable compositions of the present invention. Table 1 describes the various components of the additively manufactured radiation curable compositions used in this example.

[0176] Table 1

[0177]

[0178]

[0179] Synthesize custom parts

[0180] The custom laser dye 1 was synthesized by first dissolving 5.0 g (0.01044 mol) of the laser dye rhodamine 6G (LC5900, molecular weight (Mw) of 479.02) in 100 mL of dichloromethane (CH2Cl2). Next, 3.67 g (1.36 times) of NaSbF6 (Mw of 258.7) was dissolved in 100 mL of deionized water. Then, a magnetic stirrer (from The two solutions were mixed for 2 hours with a stirring speed ranging from 5 to 7 (RCT.B.S1 model from Works, Inc.). The resulting organic layer was extracted by removing the solvent using a rotary evaporator, followed by a vacuum step according to standard methods, to obtain 6.6 g of a red solid dye SbF6 salt, referred to herein as "Customized Laser Fuel 1."

[0181] The custom laser dye 2 was synthesized by first dissolving 5.0 g (0.01044 mol) of the laser dye Rhodamine B (LC6100, Mw 479.02) in 100 mL of dichloromethane. Next, 3.67 g (1.36 times) of NaSbF6 (Mw 258.7) was dissolved in 100 mL of deionized water. The mixture was then stirred using a magnetic stirrer (from The two solutions were mixed for 2 hours at a stirring speed ranging from 5 to 7 (RCT.B.S1 model from Works, Inc.). The resulting organic layer was extracted by removing the solvent using a rotary evaporator, followed by a vacuum step according to standard methods, to obtain 6.5 g of a red solid dye, SbF6 salt, referred to herein as "Customized Laser Dye 2."

[0182] The custom triarylmethane cationic dye 2 (Cl-modified fuchsin) was synthesized by mixing 5.0 g (0.00992 mol) of 35 fuchsin (Mw 504) was dissolved in 100 mL of dichloromethane, followed by the addition of 100 mL of 0.12 N (mol / L) HCl solution (0.012 mol) and stirred by using a magnetic stirrer (from Works, Inc., RCT.B.S1) was mixed at a stirring speed ranging from 5 to 7 for 2 hours. The resulting solution was left at room temperature (20-25 degrees Celsius) overnight. 50% of the resulting organic layer was extracted by removing the solvent using a rotary evaporator, followed by a vacuum step according to standard methods, to obtain 2.4 g of a red solid dye chloride salt, referred to herein as custom triarylmethane cation dye 2. The remaining 50% of the organic layer was used to prepare custom triarylmethane cation dye 1.

[0183] The custom triarylmethane cation dye 1 (SbF6 modified fuchsin) was synthesized by providing a portion (0.00496 mol) of the custom triarylmethane cation dye 2 specified above and dissolving it in 50 mL of dichloromethane. Next, 1.55 g of NaSbF6 (Mw of 258.7) was dissolved in 50 mL of deionized water. A magnetic stirrer (from The two solutions were mixed for 2 hours at a stirring speed ranging from 5 to 7 (RCT.B.S1 model from Works, Inc.). The resulting organic layer was extracted by removing the solvent using a rotary evaporator, followed by a vacuum step according to standard methods to obtain 3.2 g of a red solid dye antimonate, designated as a custom triarylmethane cationic dye 1.

[0184] Example

[0185] Various filled radiation curable compositions for additive manufacturing are prepared using a combination of curing photoinitiating packages, cationically polymerizable packages, free radical polymerizable packages and selected additives according to methods well known in the art. PerFORM's control "base" resin, however, contains varying amounts of various light-absorbing components.

[0186] These samples are tested according to the method for the absorbance under three kinds of different wavelengths (532nm, 405nm and 355nm) as described in further detail below.In addition, when data are provided, various compositions (to determine critical energy Ec and penetration depth Dp) are assessed according to the working curve measured value.Next, the curing speed of every kind of composition is assessed according to the epoxide of reaction and the acrylate parameter of reaction.Finally, the qualitative results of each sample drawn according to particle imaging velocity measurement (PIV) test are described below and reported.The results are described in Table 3.

[0187] viscosity

[0188] Although not reported herein, the viscosity of each sample was obtained using a Z3 / Q1 graduated cylinder (S / N 10571) with a diameter of 25 mm using an Anton Paar Rheoplus rheometer (S / N 80325376) with a spindle. The temperature was set to 30°C and the shear rate was 50 s -1 The rotation speed can be set to 38.5min -1 The measuring container can be a H-Z3 / SM cup (27.110 mm diameter), which should be filled with approximately 21 grams of sample (enough for the spindle). The measured values can be recorded in milliPa·seconds (mPa·s).

[0189] Absorption calculation (A 355 、A 405 and A 532 )

[0190] For a specified wavelength, the absorbance A (unitless) of the preparation is calculated according to the relevant expression of the Beer-Lambert law as follows:

[0191] A X =C1ε1L+C2ε2L+C3ε3L+……+C n ε n L

[0192] in

[0193] X Equal to the wavelength at which the absorption value is expected (as shown in this article, A 355 represents the absorption at 355 nm, A 405 represents the absorption at 405 nm, and A 532 represents the absorption at 532 nm);

[0194] C is the molar concentration of the corresponding component of the formulation being evaluated;

[0195] ε is the wavelength X The absorption coefficient (also called absorptivity) of the corresponding component of the preparation being evaluated;

[0196] L is the thickness of the cuvette used to perform UV spectroscopy measurements; and

[0197] 1, 2, 3, ... n represent the identifiers of the corresponding components of the preparation being evaluated.

[0198] For the purposes of this document, only the following components (if present) are included in the calculation when determining the absorbance value: photoinitiator, photosensitizer, and any light absorbing components (including but not limited to pigments, dyes, laser dyes, precursors of cyclic lactone dyes, custom or modified laser dyes, and custom triarylmethane cationic dyes). Other components in the formulation (such as cationically polymerizable monomers, free radical polymerizable monomers, and silica fillers) are intentionally excluded from the calculation.

[0199] The absorption coefficients of certain materials in certain solvents at certain wavelengths are known, but for the purposes of this article, the ε value is determined experimentally via UV / visible spectroscopy. To this end, the UV-visible absorbance of each sample was acquired using a Perkin-Elmer model λ900 (S / N101N2101201) spectrophotometer, using a 1.0 cm path cuvette quartz cell according to ASTM E169-04, and scanning the spectrum over a wavelength range of 850 nm to 250 nm. The ε value was calculated from the absorbance data. The measuring cell was filled with a sufficiently low concentration to ensure that the observed absorbance did not exceed 1.0 within the spectral range of the desired absorbance values. Therefore, for the examples shown in Tables 2 and 3 herein, the individual components were evaluated in the following manner: the following concentrations were dissolved in 100 mL of acetonitrile (MeCN):

[0200] For V952 red dispersion: 2.0×10 -4 g / mL;

[0201] For customized triarylmethane cationic dyes 1 and 2: 5.6 × 10 -6 g / mL; and

[0202] For Rhodamine 6G, Rhodamine B, and custom laser dyes 1 and 2: 3.0 × 10 -6 g / mL.

[0203] The absorbance ε of each photoinitiator, dye, or pigment at wavelengths of 355 nm, 405 nm, and 532 nm was then recorded and used in calculations using the formula for determining absorbance described above. The overall absorbance value was determined by comparing the value of the relevant added light-absorbing component with the reported value of the base resin ( PerFORM; as reported herein above by the manufacturer in Table 1 and recorded below in Table 3) are summed. For example, the absorbance value at 355 nm for Comparative Example 2 (which consisted of 50 parts PerFORM and 0.030 parts Copikem Orange) was determined as follows:

[0204] A 355 =C PerFORM ×ε PerFORM ×L+CCopikemOrange ×ε CopikemOrange ×L→

[0205] A 355 = 39.47 (reported by the manufacturer) + 3.74 (obtained according to the above procedure) = 43.21

[0206] Working curve measurement

[0207] Working curve data (E) were prepared using a solid-state laser operating at a wavelength of 354.7 nm according to the following method. c 、D p and E 10 ).

[0208] The working curve is a measure of the photospeed of a particular material. It represents the functional relationship between the thickness of the radiation-curable composition layer produced and a given exposure. For all formulations, the exposure-working curve of the formulation was determined using methods well known in the art.

[0209] The exposure response of each formulation was measured using 21.7 g of formulation samples in a 100 mm diameter petri dish maintained at 30°C and 30% RH. The surface of the formulation was exposed to the indicated light source. The exposure was performed in half-inch squares (exposure areas) by scanning continuous parallel lines spaced approximately 25.4 microns apart at 72 mW on the surface of the liquid in the petri dish. Different exposure areas were exposed to different levels of known incident energy to obtain different cured thicknesses. The spot diameter at the liquid surface was approximately 0.0277 cm. After waiting for at least 15 minutes for the exposed panel to harden, the panel was removed from the petri dish and excess uncured resin was removed by blotting with a Kimwipe EX-L (Kimberly Clark). Film thickness was measured using a Mitutoyo model ID-C 1 12CE indicator micrometer. Film thickness is a linear function of the natural logarithm of the exposure energy; the regression slope is D p (in microns or mils), and E c is the x-intercept of the regression fit (in mJ / cm 2 E 10 is the energy required to cure a ten mil (254 micron) layer.

[0210] Cure Speed Measurements (% of Epoxide Reacted (10.0 min) and % of Acrylate Reacted (50 ms))

[0211] To measure the polymerization rate (curing speed) of each example, real-time Fourier transform infrared (FTIR) spectroscopy was used. Instead of transmission mode, an attenuated total reflectance (ATR) setup was used. All polymerization rate measurements were performed using a Thermo Scientific Nicolet Nexus 470 model equipped with an MCT detector or equivalent. The following table shows the experimental conditions used for the measurements.

[0212] Sample scan times 10 Resolution <![CDATA[4.000cm -1 ]]> Types of Data Collected real time spectral range <![CDATA[4000-650cm -1 ]]> Background scan times 32 Final format absorbance

[0213] For the cure speed measurements reported in this article, samples were tested after exposure to a solid-state laser operating at a peak wavelength of 355 nm. The laser used was a 100 mW solid-state 355 nm Nd:YAG laser (Xcyte Model CY-355-100, using a power supply model CY-PS). The following steps were taken to couple the 355 nm solid-state laser to the FTIR setup described above: First, a housing was constructed that fit over the FTIR sample chamber. Next, the laser was mounted toward the back of the top frame, with the laser output directed toward and centered within the sample chamber. A 1” hole was then drilled in the top plate at a location centered over the diamond. Once the hole was drilled, a movable plane mirror was mounted above the hole to direct the laser beam toward the diamond. A variable neutral density filter was then installed in the path of the laser beam to enable intensity control. Next, an electronic shutter model λSC SmartShutter with a controller was installed in the laser beam path. Finally, the shutter driver software was installed on the FTIR computer.

[0214] A solid-state laser coupled to an FTIR device was used, and the light intensity was selected to be 22 mW / cm 2 The exposure time was controlled at 25 milliseconds (ms) (as measured by a Gentec Model TPM-300 radiometer or equivalent).

[0215] In order to measure, a few drops of selected sample are placed in the center of the ATR crystal setting. Then, a film of about 3 mils (± 0.4 mils) is coated on the top of the ATR crystal using a 3 mil (± 0.4 mil) pull-down bird bar. After applying the 3 mil coating, real-time FTIR scanning is started immediately. Once a spectrum A is obtained, the light source is turned on for 25ms to start polymerization. A new spectrum B is obtained at 50ms for acrylate conversion calculations, and another new spectrum C is obtained at 10 minutes for epoxy conversion calculations.

[0216] The relationship between polymerization conversion and time was calculated based on the change in the specific IR peak representing each functional group. In order to calculate the conversion of each relevant functional group, the peak area was first calculated appropriately according to the following table:

[0217] functional groups method <![CDATA[Area (cm -1 )]]> <![CDATA[Baseline (cm -1 )]]> Epoxy area 927.608-879.395 927.608-879.395 Acrylate area 1419.375-1396.233 1419.375-1396.233

[0218] Use the "Peak Area" software tool on your FTIR system to measure the peak area of the selected peak for each spectrum. Next, set the baseline point so that it is as tangent to the spectrum as possible on both sides of the peak. Next, set the area point to the same value as the baseline point. Finally, record the area.

[0219] To calculate the percentage of each reacted species in each spectrum, the following equation was used:

[0220]

[0221] Where: A(liquid) = the net area of the peak of liquid spectrum A; and

[0222] A(exposed) = net area of the peak after exposure.

[0223] Qualitative PIV adaptability testing

[0224] For this test, 50g of each formulation was prepared according to standard methods, and DMA tapes of each component were created on a Viper SLA machine (S / N 03FB0244 or S / N 02FB0160). When making the DMA tapes, the Viper machine build platform was fixed in place, and a 6" x 8" sheet of 10-mil Mylar film was placed on the platform and fixed. Next, 5 mils of liquid resin was applied to the film by hand using a doctor blade, after which the laser was scanned over the liquid resin to build four DMA tapes measuring 4" x 1.5". After this, a second 5 mils of liquid was applied on top of the first cured layer by controlling the doctor blade gap of 10 mils, and the liquid was then cured to build the second layer of DMA tape. This process was repeated until six layers of 30-mil thick DMA tapes were completed. The green parts were then cleaned with IPA solvent and post-cured twice for 30 minutes in a post-curing apparatus, after which they were aged for 7 days in a temperature and humidity controlled room (25°C at 50% RH). PerFORM) was constructed in the same manner. For each example, a set of 4 DMA strips was constructed. No DMA strip was subsequently post-processed by adding a coating, foil, or paint. In fact, all DMA strips formed a component with a substantially homogeneous structure.

[0225] Each part was then tested by shining a laser beam at the test strip at a distance and under standard environmental conditions for PIV testing. Figure 1An example of such a setup is depicted. In such an exemplary setup, a laser 1 emits light at a PIV wavelength 2 through a lens 3. The lens, preferably a cylindrical lens, should distribute the light at the PIV wavelength broadly into a light sheet 4 that illuminates at least a target area 8. Simultaneously, an unfoiled, unpainted object 5 (which is a cured product of a radiation curable composition according to the present invention) is then appropriately placed between the imaging optics 7 and the target area. With the object 5 appropriately positioned, an airflow (closely representing the fluid) seeded with neutral suspended particles 6 is directed into and across the object to produce a desired fluid flow pattern across one or more surfaces of the object. A charge coupled device (CCD) image sensor 9 is then electrically coupled to the imaging optics to enable imaging of the airflow over the object 5. The raw imaging captured by the CCD 9 is then placed through a correlation activity, and the data is then converted and provided into a relevant / calibrated form 11. Finally, data analysis is performed by various software and analysis tools to draw conclusions about the relative performance of the airflow over or around the finished part for which the object 5 is considered to be a sufficient surrogate.

[0226] Turning to the actual test run, the laser used was a frequency-doubled Nd:YAG (neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O 12 , operating at a peak wavelength of 532nm), and recording the reflected image. This process was repeated 4 times; once for each corresponding DMA strip for each sample. The level of reflective intensity was qualitatively determined. If the part showed no visually discernible difference in image brightness and blurriness from the control sample (the control sample is known in the industry to be insufficient for PIV testing without the need for post-processing steps such as the addition of coatings, foils or paints), the part was considered "unqualified"; parts that showed visually observable improved clarity and reduced reflection relative to the control were considered "qualified". If the results of the 4 tests were inconclusive or varied, they were considered "inconclusive". Each embodiment for which this test was not run was reported as "no data". The results are reported in Table 3 below.

[0227] Table 2

[0228] Amounts reported in parts by weight

[0229]

[0230]

[0231] Table 3

[0232] Nd = No Data

[0233]

[0234]

[0235] Results and Discussion

[0236] These results demonstrate the superiority of the compositions described herein in being suitable for producing cured parts with sufficient application-specific heat resistance and structural stiffness, capable of producing parts capable of PIV testing with enhanced image resolution and without the need for post-processing, and sufficient cure speed to ensure suitability in additive manufacturing processes such as stereolithography.

[0237] In order to further illustrate certain aspects of the present invention, the present invention also specifically provides the following non-limiting embodiments:

[0238] Embodiment 1) A method of performing particle imaging velocimetry testing using an object created via additive manufacturing, the method comprising:

[0239] Providing test parts created via additive manufacturing;

[0240] immersing the test component in a flow field seeded with tracer particles;

[0241] illuminating at least a portion of the broadcast flow field proximate the component with light of a first wavelength;

[0242] capturing a plurality of images using an imaging system;

[0243] evaluating the image to determine a flow vector proximate the test part;

[0244] The test parts were uncoated, unfoiled and unpainted.

[0245] Embodiment 2) A method according to the aforementioned embodiment, wherein the test part created via additive manufacturing has a tensile modulus of at least about 6 gigapascals (GPa), or about 6 GPa to about 20 GPa, or about 7 GPa to about 15 GPa as measured according to ASTM D638-14, and a heat deformation temperature of at least about 60 degrees Celsius (°C), or at least about 70 degrees Celsius (°C), or at least about 100 degrees Celsius (°C), or about 65°C to about 100°C, or about 65°C to about 110°C, or about 70°C to about 90°C as measured at 1.82 MPa according to ASTM D648-16.

[0246] Embodiment 3) A method according to any of the preceding embodiments, wherein the test component has a substantially homogeneous construction.

[0247] Embodiment 4) Method according to any of the preceding embodiments, wherein the test component is a cured product of a composition comprising a filler.

[0248] Embodiment 5) The method according to any of the preceding embodiments, wherein the test component is a cured product of a composition comprising a free radical polymerizable monomer and a free radical photoinitiator.

[0249] Embodiment 6) The method according to any of the preceding embodiments, wherein the test component is a cured product of a composition comprising a cationically polymerizable monomer and a cationic photoinitiator.

[0250] Embodiment 7) A method according to any of the preceding embodiments, wherein the test component is a cured product of a composition comprising one or more light absorbing components.

[0251] Embodiment 8) The method according to any of the preceding embodiments, wherein the test component is a cured product of a composition comprising a pigment, a laser dye, a cyclic lactone dye precursor, or a combination thereof.

[0252] Embodiment 9) Method according to any of the preceding embodiments, wherein the test part is a cured product of a composition comprising a pigment and a laser dye, or a pigment and a cyclic lactone dye precursor.

[0253] Embodiment 10) The method according to any of the preceding embodiments, wherein the test component is a cured product of a composition comprising a pigment, a laser dye and a cyclic lactone dye precursor.

[0254] Embodiment 11) The method according to any one of the preceding embodiments, wherein the test component is a cured product of a composition comprising a compound defined by the formula:

[0255]

[0256] wherein R1, R2, R3, R4, R5 and R6 each independently represent a hydrogen atom, a substituted methyl or alkyl group, or an unsubstituted methyl or alkyl group; and R7 represents an unsubstituted phenyl group or a substituted phenyl group.

[0257] Embodiment 12) A method according to the preceding embodiment, wherein R7 represents a benzoate group.

[0258] Embodiment 13) A method according to any of the preceding embodiments, wherein the test component is a cured product of a composition selectively exposed to actinic radiation of a second wavelength via the additive manufacturing process.

[0259] Embodiment 14) A method according to the preceding embodiment, wherein the additive manufacturing process is stereolithography and the second wavelength is about 355 nm.

[0260] Embodiment 15) The method of any one of the two preceding embodiments, wherein the composition has a penetration depth of at least about 2.5, or at least about 3, or at least about 3.5 to less than 6, or less than 5, or less than 4.5, or 2.5-4.5, or 3-4.5 when tested at the second wavelength.

[0261] Embodiment 16) A method according to any of the preceding embodiments, wherein the illuminating step is performed by a light source comprising a laser, and wherein the first wavelength of light is approximately 532 nanometers.

[0262] Embodiment 17) A method according to any of the preceding embodiments, wherein the first wavelength is higher than the second wavelength, and wherein the difference between the first wavelength and the second wavelength is about 100 to about 300 nanometers, or about 120-180 nanometers, or about 130-170 nanometers.

[0263] Embodiment 18) A method according to any of the preceding embodiments, wherein the test component has an absorbance of at least 10, or at least 15, or at least 20, or at least 25, or at least 30, or 10-1000, or 15-500, or 20-200, or 25-150, or 30-100, or 30-80, or 35-75 under light of the first wavelength.

[0264] Embodiment 19) A method according to any of the preceding embodiments, wherein the test component has an absorbance of less than 100, or less than 80, or less than 60, or less than 50, or less than 45, or at least 25, or at least 35, or at least 39, or 25-100, or 25-80, or 25-60, or 25-50, or 25-45, or 35-100, or 35-80, or 35-60, or 35-45, or 35-50, or 39-100, or 39-80, or 39-60, or 39-50, or 39-45 under light of the second wavelength.

[0265] Embodiment 20) The method of any of the preceding embodiments, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is from about -50 to 200, or from about -30 to about 200, or from about -30 to about 150, or from about -30 to about 100, or from about -30 to about 80, or from about -30 to about 60, or from about -30 to about 30, or from about -30 to about 20, or from about -30 to about 10, or from about -30 to about 0, or from about -30 to about -10, or from about -20 to about 100, or from about -20 to about 80, or from about -20 to about 60, or from about -20 to about 30, or from about -20 to about 30 or about -20 to about 10, or about -20 to about 0, or about -20 to about -10, or about -10 to about 100, or about -10 to about 80, or about -10 to about 60, or about -10 to about 30, or about -10 to about 20, or about -10 to about 10, or about -10 to about 0, or between 0 and 150, or between 0 and 100, or between 0 and 50, or between 0 and 30, or between 10 and 150, or between 10 and 100, or between 10 and 50, or between 20 and 200, or between 20 and 100, or between 20 and 50.

[0266] Embodiment 21) A method according to any of the preceding embodiments, wherein the test part is a cured product of a composition configured to obtain a % reacted epoxide (at 10.0 minutes) of at least about 10%, or at least about 13%, or at least about 15%, or at least about 20%, or at least about 25%, or from about 10% to about 50%, or from about 10% to about 30%, or from about 13% to about 25%.

[0267] Embodiment 22) A method according to any of the preceding embodiments, wherein the test part is a cured product of a composition configured to obtain a % reacted acrylate (at 50 milliseconds) of at least about 20%, or at least about 25%, or at least about 30%, or at least about 40%, or about 20%-100%, or about 25% to about 80%, or about 30% to about 55%.

[0268] Embodiment 23) A radiation curable composition for additive manufacturing, comprising:

[0269] a free radical polymerizable component;

[0270] Free radical photoinitiators;

[0271] Filler ingredients;

[0272] and one or more light absorbing components;

[0273] wherein the composition is configured to have an absorbance at 532 nm of at least 10, or at least 15, or at least 20, or at least 25, or at least 30, or 10-1000, or 15-500, or 20-200, or 25-150, or 30-100, or 30-80, or 35-75.

[0274] Embodiment 24) The radiation curable composition according to the preceding embodiment, wherein the free radical polymerizable component is present in an amount of 5-40 wt. % and the filler component is present in an amount of 25-65 wt. %, relative to the weight of the entire composition.

[0275] Embodiment 25) A radiation curable composition according to the preceding embodiment, wherein the one or more light absorbing components are present in an amount of about 0.005 wt % to about 10 wt %, or about 0.01 wt % to about 5 wt %, or about 0.01 wt % to about 0.5 wt %, relative to the weight of the entire composition.

[0276] Embodiment 26) The radiation curable composition of the preceding embodiment, wherein the composition has a penetration depth (Dp) of at least about 2.5, or at least about 3, or at least about 3.5, to less than 6, or less than 5, or less than 4.5, or 2.5-4.5, or 3-4.5 when tested at 355 nm.

[0277] Embodiment 27) The radiation curable composition for additive manufacturing according to the previous embodiment further comprising a cationically polymerizable component and a cationic photoinitiator.

[0278] Embodiment 28) The radiation curable composition for additive manufacturing according to the previous embodiment, wherein the cationic polymerizable component is present in an amount of 10-50 weight percent and the cationic photoinitiator is present in an amount of 0.1-5 weight percent, wherein all weights are expressed relative to the weight of the entire composition.

[0279] Embodiment 29) The radiation curable composition of any of the preceding embodiments, wherein the one or more light absorbing components comprise a pigment, a laser dye, or a cyclic lactone dye precursor.

[0280] Embodiment 30) The radiation curable composition according to any of the preceding embodiments, wherein the composition comprises a pigment and a laser dye, or a pigment and a cyclic lactone dye precursor.

[0281] Embodiment 31) A radiation curable composition according to any of the preceding embodiments, wherein the laser dye comprises a compound of the formula:

[0282]

[0283] wherein R1, R2, R3, R4, R5 and R6 each independently represent a hydrogen atom, a substituted methyl or alkyl group, or an unsubstituted methyl or alkyl group; and R7 represents an unsubstituted phenyl group or a substituted phenyl group.

[0284] Embodiment 32) The radiation curable composition according to the preceding embodiment, wherein R7 is a benzoate group.

[0285] Embodiment 33) A radiation curable composition for additive manufacturing comprising, relative to the weight of the total composition:

[0286] (a) 25-65% by weight of a filler component;

[0287] (b) 10-50% by weight of a cationically polymerizable component;

[0288] (c) 5-40% by weight of a free radical polymerizable component;

[0289] (d) an effective amount of a cationic photoinitiator;

[0290] (e) an effective amount of a free radical photoinitiator; and

[0291] (f) Light absorbing components.

[0292] Embodiment 34) The radiation curable composition according to the previous embodiment, wherein the light absorbing component is an organic salt, preferably an ammonium salt.

[0293] Embodiment 35) The radiation curable composition according to any of the preceding embodiments, wherein the organic salt is according to the following formula (IV):

[0294]

[0295] in

[0296] X and X' represent Cl – Br – , I – 、SO4 2– 、NO3 – 、ClO4 – 、AsF6 – 、SbF6 – PF6 – 、BF4 – 、(CF3CF2)3PF3 – 、(C6F5)4B – 、((CF3)2C6H3)4B –、(C6F5)4Ga – 、((CF3)2C6H3)4Ga – , trifluoromethanesulfonate, nonafluorobutanesulfonate, methanesulfonate, butanesulfonate, benzenesulfonate, or p-toluenesulfonate;

[0297] R1, R2, R3, R4, R5 and R6 each independently represent a hydrogen atom, a substituted methyl or alkyl group, or an unsubstituted methyl or alkyl group; and

[0298] R7 represents a hydrogen atom, an unsubstituted phenyl group, or a substituted phenyl group.

[0299] Embodiment 36) A radiation curable composition according to the preceding embodiment, wherein X or X' represents Cl – Br – , I – 、SO4 2– 、NO3 – 、ClO4 – 、AsF6 – 、SbF6 – or PF6 – , preferably wherein X or X' represents antimony hexafluoride (SbF6) - ion.

[0300] Embodiment 37) The radiation curable composition according to any of the preceding embodiments, wherein the cationic photoinitiator further comprises an anion, wherein the anion is also defined by X or X'.

[0301] Embodiment 38) The radiation curable composition of any of the preceding embodiments, wherein the anion of the cationic photoinitiator has the same moiety as the X or X' moiety in the light absorbing component.

[0302] Embodiment 39) The radiation curable composition of any of the preceding embodiments, wherein the light absorbing component comprises a fluorine antimony counter ion, and further wherein the light absorbing compound is different from (d).

[0303] Embodiment 40) A radiation curable composition according to the preceding embodiment wherein the fluoroantimony modified compound is a SbF6 modified laser dye or a modified triarylmethane cationic dye from a cyclic lactone precursor.

[0304] Embodiment 41) The radiation curable composition according to any of the preceding embodiments, further comprising a pigment.

[0305] Embodiment 42) The radiation curable composition of any of the preceding embodiments, wherein the filler component comprises a plurality of organic or inorganic microparticles or nanoparticles.

[0306] Embodiment 43) The radiation curable composition according to any of the preceding embodiments, wherein the filler component consists of a combination of inorganic microparticles and inorganic nanoparticles.

[0307] Embodiment 44) The radiation curable composition of any of the preceding embodiments, wherein the filler component consists essentially of a combination of inorganic microparticles and inorganic nanoparticles.

[0308] Embodiment 45) The radiation curable composition of any of the preceding embodiments, wherein the weight ratio of the inorganic microparticles to the inorganic nanoparticles is from 1:1 to 12:1.

[0309] Embodiment 46) The radiation curable composition according to any one of the preceding embodiments, wherein the inorganic microparticles and the inorganic nanoparticles have an average particle size, wherein the ratio of the average particle size of the inorganic microparticles to the average particle size of the inorganic nanoparticles is 2.41:1 to less than 200:1, or 2.41:1 to 100:1, or 6.46:1 to less than 200:1, or 6.46:1 to 100:1, wherein the average particle size of the inorganic microparticles and the inorganic nanoparticles is determined by ISO13320:2009.

[0310] Embodiment 47) The radiation curable composition of any of the preceding embodiments, wherein the average particle size of the inorganic nanoparticles is from 50 nanometers (nm) to 200 nm, or from 50 nm to 100 nm.

[0311] Embodiment 48) The radiation curable composition according to any of the preceding embodiments, wherein the average particle size of the inorganic microparticles is from 2 μm to 8 μm.

[0312] Embodiment 49) The radiation curable composition of any of the preceding embodiments further comprising 5 wt% to 15 wt% of an oxetane.

[0313] Embodiment 50) The radiation curable composition according to any of the preceding embodiments further comprising 0.001 wt% to 0.5 wt% of a stabilizer.

[0314] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0315] Unless otherwise indicated herein or obviously contradictory to the context, the use or non-use of quantifiers of the terms "one" and "an" and "the" and similar indicators in the context of describing the present invention (especially in the context of the following claims) should be interpreted as covering both the singular and the plural. Unless otherwise indicated, the terms "comprise", "have", "include" and "contain" should be interpreted as open terms (that is, meaning "including but not limited to"). Unless otherwise indicated herein, the description of value ranges herein is only intended to be used as a shorthand method for quoting each individual value falling within the scope, and each individual value is incorporated into this specification as if it were individually quoted herein. Unless otherwise indicated herein or obviously contradictory to the context, all methods described herein can be performed in any suitable order. Unless otherwise claimed, the use of any and all examples, or exemplary language (such as "such as") provided herein is only intended to better illustrate the present invention, rather than to limit the scope of the present invention. Any language in the specification should not be interpreted as indicating that any unclaimed element is essential for the practice of the present invention.

[0316] The preferred embodiments of the present invention are described herein, including the best mode known to the inventors for implementing the present invention. By reading the foregoing description, variations of those preferred embodiments will become apparent to those of ordinary skill in the art. The inventors hope that technicians will appropriately adopt such variations, and the inventors hope to practice the present invention in a manner different from that specifically described herein. Therefore, the present invention includes all modifications and equivalents of the subject matter described in the appended claims herein as allowed by applicable law. In addition, unless otherwise specified herein or clearly contradicted by the context, the present invention encompasses any combination of all possible variations of the above-mentioned elements.

[0317] While the invention has been described in detail with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as claimed.

Claims

1. A method of performing particle imaging velocimetry testing using an object created via additive manufacturing, the method comprising: Providing test parts created via additive manufacturing; immersing the test component in a flow field seeded with tracer particles; illuminating at least a portion of the seeded flow field proximate the test component with light of a first wavelength; capturing a plurality of images using an imaging system; evaluating the image to determine a flow vector proximate the test part; wherein the test parts are uncoated, unfoiled and unpainted, wherein the test part is a cured product of a radiation curable composition comprising a filler and one or more light absorbing components and selectively exposed to actinic radiation of a second wavelength via an additive manufacturing process, and wherein the test component has an absorbance of at least 10 at the first wavelength of light and an absorbance of less than 100 at the second wavelength of light; and The first wavelength of light is 532 nm.

2. The method of claim 1 , wherein the test part created via additive manufacturing has a tensile modulus of at least 6 gigapascals as measured according to ASTM D638-14, and a heat deflection temperature of at least 60 degrees Celsius as measured at 1.82 megapascals as measured according to ASTM D648-16.

3. The method of claim 2, wherein the test part created via additive manufacturing has a tensile modulus of 6 to 20 GPa as measured according to ASTM D638-14.

4. The method of claim 2, wherein the test part created via additive manufacturing has a tensile modulus of 7 to 15 GPa as measured according to ASTM D638-14.

5. The method of claim 2, wherein the test part created via additive manufacturing has a heat deflection temperature of at least 70 degrees Celsius measured at 1.82 MPa according to ASTM D648-16.

6. The method of claim 2, wherein the test part created via additive manufacturing has a heat deflection temperature of at least 100 degrees Celsius as measured at 1.82 megapascals according to ASTM D648-16.

7. The method of claim 2, wherein the test part created via additive manufacturing has a heat deflection temperature of 65 degrees Celsius to 100 degrees Celsius measured at 1.82 MPa according to ASTM D648-16.

8. The method of claim 2, wherein the test part created via additive manufacturing has a heat deflection temperature of 65 degrees Celsius to 110 degrees Celsius measured at 1.82 MPa according to ASTM D648-16.

9. The method of claim 2, wherein the test part created via additive manufacturing has a heat deflection temperature of 70 degrees Celsius to 90 degrees Celsius measured at 1.82 MPa according to ASTM D648-16.

10. The method according to claim 1 or 2, wherein the test component has a homogeneous construction.

11. The method according to claim 1 or 2, wherein the test part is a cured product of a composition comprising a free radical polymerizable monomer and a free radical photoinitiator.

12. The method according to claim 1 or 2, wherein the test part is a cured product of a composition comprising a cationically polymerizable monomer and a cationic photoinitiator.

13. The method according to claim 1 or 2, wherein the test part is a cured product of a composition comprising a pigment, a laser dye, a cyclic lactone dye precursor or a combination thereof.

14. The method according to claim 1 or 2, wherein the test component is a cured product of a composition comprising a compound defined by the following formula: wherein R1, R2, R3, R4, R5 and R6 each independently represent a hydrogen atom, a substituted alkyl group, or an unsubstituted alkyl group; and R7 represents an unsubstituted phenyl group or a substituted phenyl group.

15. The method according to claim 14, wherein R7 represents a benzoate group.

16. The method of claim 1, wherein the additive manufacturing process is stereolithography and the second wavelength is 355 nanometers.

17. The method of claim 1 or 2, wherein irradiating at least a portion of the seeded flow field proximate the component with light of a first wavelength is performed by a light source comprising a laser.

18. The method of the preceding claim 1, wherein the first wavelength is higher than the second wavelength, and wherein the difference between the first wavelength and the second wavelength is 100 to 300 nanometers.

19. The method of the preceding claim 1, wherein the first wavelength is higher than the second wavelength, and wherein the difference between the first wavelength and the second wavelength is 120 to 180 nanometers.

20. The method of the preceding claim 1, wherein the first wavelength is higher than the second wavelength, and wherein the difference between the first wavelength and the second wavelength is 130 to 170 nanometers.

21. The method of claim 1 or 2, wherein the test component has an absorbance of at least 15 at the first wavelength of light.

22. The method of claim 1 or 2, wherein the test component has an absorbance of at least 20 at the first wavelength of light.

23. The method of claim 1 or 2, wherein the test component has an absorbance of at least 25 at the first wavelength of light.

24. The method of claim 1 or 2, wherein the test component has an absorbance of at least 30 at the first wavelength of light.

25. The method according to claim 1 or 2, wherein the test component has an absorbance of 10-1000 under the first wavelength of light.

26. The method according to claim 1 or 2, wherein the test component has an absorbance of 15-500 at the first wavelength of light.

27. The method according to claim 1 or 2, wherein the test component has an absorbance of 20-200 at the first wavelength of light.

28. The method according to claim 1 or 2, wherein the test component has an absorbance of 25-150 at the first wavelength of light.

29. The method according to claim 1 or 2, wherein the test component has an absorbance of 30-100 at the first wavelength of light.

30. The method of claim 1 or 2, wherein the test component has an absorbance of 30-80 at the first wavelength of light.

31. The method of claim 1 or 2, wherein the test component has an absorbance of 35-75 at the first wavelength of light.

32. The method of claim 1, wherein the test component has an absorbance of less than 80 at the second wavelength of light.

33. The method of claim 1, wherein the test component has an absorbance of less than 60 at the second wavelength of light.

34. The method of claim 1, wherein the test component has an absorbance of less than 50 at the second wavelength of light.

35. The method of claim 1, wherein the test component has an absorbance of less than 45 at the second wavelength of light.

36. The method of claim 1, wherein the test component has an absorbance of at least 25 at the second wavelength of light.

37. The method of claim 1, wherein the test component has an absorbance of at least 35 at the second wavelength of light.

38. The method of claim 1, wherein the test component has an absorbance of at least 39 at the second wavelength of light.

39. The method of claim 1, wherein the test component has an absorbance of 25-80 at the second wavelength of light.

40. The method of claim 1, wherein the test component has an absorbance of 25-60 at the second wavelength of light.

41. The method of claim 1, wherein the test component has an absorbance of 25-50 at the second wavelength of light.

42. The method of claim 1, wherein the test component has an absorbance of 25-45 at the second wavelength of light.

43. The method of claim 1, wherein the test component has an absorbance of 35-80 at the second wavelength of light.

44. The method of claim 1, wherein the test component has an absorbance of 35-60 at the second wavelength of light.

45. The method of claim 1, wherein the test component has an absorbance of 35-45 at the second wavelength of light.

46. The method of claim 1, wherein the test component has an absorbance of 35-50 at the second wavelength of light.

47. The method of claim 1, wherein the test component has an absorbance of 39-80 at the second wavelength of light.

48. The method of claim 1, wherein the test component has an absorbance of 39-60 at the second wavelength of light.

49. The method of claim 1, wherein the test component has an absorbance of 39-50 at the second wavelength of light.

50. The method of claim 1, wherein the test component has an absorbance of 39-45 at the second wavelength of light.

51. The method of claim 1 , wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -50 and 200.

52. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 200.

53. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 150.

54. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 100.

55. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 80.

56. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 60.

57. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 30.

58. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 20.

59. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 10.

60. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and 0.

61. The method of claim 1 , wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -30 and -10.

62. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and 100.

63. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and 80.

64. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and 60.

65. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and 30.

66. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and 20.

67. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and 10.

68. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and 0.

69. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -20 and -10.

70. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -10 and 100.

71. The method of claim 1 , wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -10 and 80.

72. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -10 and 60.

73. The method of claim 1 , wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -10 and 30.

74. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -10 and 20.

75. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -10 and 10.

76. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between -10 and 0.

77. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 0 and 150.

78. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 0 and 100.

79. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 0 and 50.

80. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 0 and 30.

81. The method of claim 1 , wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 10 and 150.

82. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 10 and 100.

83. The method of claim 1 , wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 10 and 50.

84. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 20 and 200.

85. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 20 and 100.

86. The method of claim 1, wherein the absorbance of the test component at the first wavelength minus the absorbance at the second wavelength is between 20 and 50.

87. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide at 10.0 minutes of at least 10%.

88. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide of at least 13% at 10.0 minutes.

89. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide of at least 15% at 10.0 minutes.

90. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide of at least 20% at 10.0 minutes.

91. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide of at least 25% at 10.0 minutes.

92. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide at 10.0 minutes of 10% to 50%.

93. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide at 10.0 minutes of 10% to 30%.

94. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % Reacted Epoxide of 13% to 25% at 10.0 minutes.

95. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % reacted acrylate of at least 20% at 50 milliseconds.

96. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % reacted acrylate of at least 25% at 50 milliseconds.

97. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % reacted acrylate of at least 30% at 50 milliseconds.

98. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % reacted acrylate of at least 40% at 50 milliseconds.

99. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % reacted acrylate of 20% to 100% at 50 milliseconds.

100. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % reacted acrylate of 25% to 80% at 50 milliseconds.

101. The method of claim 1 or 2, wherein the test part is a cured product of a composition configured to achieve a % reacted acrylate of 30% to 55% at 50 milliseconds.

102. The method according to claim 14, wherein R1, R2, R3, R4, R5 and R6 each independently represent a substituted methyl group or an unsubstituted methyl group.

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