Fdm printed article with doped material

Abstract

The present invention provides a method for producing a 3D article (1) by fused deposition modeling, the method comprising a 3D printing stage comprising layer-by-layer deposition of an extrusion (321) comprising a 3D printable material (201) to provide a 3D article (1) comprising a 3D printed material (202), wherein the 3D article (1) comprises layers (322) of the 3D printed material (202), wherein the method further comprises controlling a first temperature T1 of the 3D printable material (201) within a first temperature range, wherein the 3D printable material (201) comprises a thermoplastic host material (401) and a dopant material (410) in the range of 1-20 vol.%, the dopant material (410) comprising sheet-like polymer particles having a metallic coating, wherein the 3D printable material (201) has the property that when the temperature of the 3D printable material (201) increases above a change temperature T c The optical property that irreversibly changes from low-temperature optical properties to high-temperature optical properties, selected from the group consisting of reflectivity, transmittance, luminosity, absorptivity, and color, wherein the temperature of change T is... c Within a first temperature range, wherein during at least a first portion of the 3D printing phase, the first temperature T1 is lower than the varying temperature T. c Furthermore, during at least the second part of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c .

Description

Technical Field

[0001] This invention relates to a method for manufacturing 3D (printed) articles. Furthermore, the invention may relate to software products for performing this method. The invention also relates to 3D (printed) articles obtainable through this method. Additionally, the invention relates to a lighting device comprising such a 3D (printed) article. Furthermore, the invention may also relate to a 3D printer, such as a 3D printer used in or for this method. Background Technology

[0002] The use of thermoplastic polymers containing particulate fillers for the preparation of 3D articles is known in the art. For example, WO2017 / 040893 describes a powder composition comprising a plurality of thermoplastic particles characterized by a bimodal particle size distribution, and wherein the powder composition may further comprise particulate fillers, antioxidants, heat stabilizers, light stabilizers, ultraviolet light stabilizers, ultraviolet light absorbing additives, near-infrared light absorbing additives, infrared light absorbing additives, plasticizers, lubricants, mold release agents, antistatic agents, antifogging agents, antibacterial agents, colorants, laser marking additives, surface effect additives, radiation stabilizers, flame retardants, anti-drip agents, fragrances, fibers, or combinations comprising at least one of the above (preferably colorants or metal particles). This document further describes a method for preparing a three-dimensional article, the method comprising melting a powder composition into a powder bed to form a three-dimensional article. Summary of the Invention

[0003] Over the next 10-20 years, digital manufacturing will increasingly transform the nature of global manufacturing. One aspect of digital manufacturing is 3D printing. Currently, many different technologies have been developed to produce a wide variety of 3D printed objects using a variety of materials such as ceramics, metals, and polymers. 3D printing can also be used to produce molds, which can then be used to replicate objects.

[0004] Polymer jetting technology has been proposed for use in mold making. This technology utilizes the layer-by-layer deposition of photopolymerizable materials, which are cured after each deposition to form a solid structure. While this technology produces a smooth surface, photopolymerizable materials are not very stable and they also have relatively low thermal conductivity, which is useful for injection molding applications.

[0005] The most widely used additive manufacturing technology is a process called Fused Deposition Modeling (FDM). Fused Deposition Modeling (FDM) is an additive manufacturing technology commonly used for molding, prototyping, and production applications. FDM works on the principle of "additive manufacturing" by laying down materials in layers; plastic or metal filaments are released from coils, and material is supplied to produce parts. Possibly (for example, in the case of thermoplastics), the filament is melted and extruded before being laid down. FDM is a rapid prototyping technology. Other terms for FDM are "Fused Filament Manufacturing" (FFF) or "Filament 3D Printing" (FDP), which are considered equivalent to FDM. Typically, FDM printers use thermoplastic filaments that are heated to their melting point and then extruded to create three-dimensional objects layer by layer (or practically filament-to-filament). FDM printers are relatively fast, low-cost, and can be used to print complex objects. These printers are used to print a wide variety of shapes using various polymers. The technology is also being further developed in the production of LED luminaires and lighting solutions.

[0006] It may be desirable for 3D-printed articles to have optical effects that vary depending on the parts of the 3D-printed article. For example, it may be desirable for one part to be reflective while another part is less or essentially non-reflective. Flash sheets are a class of materials that can give lamps an attractive appearance. Flash sheets are produced by cutting a polymer film (particularly PET film) into thin layers of aluminum that are (essentially) flattened particles with precise dimensions and shapes (e.g., hexagons, rectangular stars, triangles, circles, etc.). The film can also have microstructures (to give the flash a more attractive appearance). For example, in one embodiment, the flash sheet could be a holographic flash sheet. However, when using flash sheets, different optical properties can only be achieved by using different 3D-printable materials, namely a first material that includes or does not include flash sheets and a second material that does not include or includes flash sheets. Similarly, this can be applied to other types of additives that can impart optical effects to 3D-printable materials. This can make 3D printing more complex and / or make more sophisticated 3D printing equipment necessary.

[0007] Therefore, one aspect of the present invention is to provide an alternative 3D printing method and / or 3D (printed) article, which preferably further eliminates at least partially one or more of the aforementioned disadvantages. The object of the present invention may be to overcome or improve upon at least one disadvantage of the prior art, or to provide a useful alternative.

[0008] In a first aspect, the present invention provides a method for producing 3D articles by fused deposition modeling. The method includes a 3D printing stage comprising layer-by-layer deposition of an extrusion comprising a 3D-printable material to provide a 3D article. The 3D article comprises the 3D-printed material. Deposition can be particularly performed on a receiver article. The 3D article comprises layers of the 3D-printed material. The method further includes controlling a first temperature T1 of the 3D-printable material within a first temperature range. The 3D-printable material comprises a thermoplastic host material and a dopant material in the range of 1-20 vol.%, wherein the dopant material comprises polymer flake particles with a metallic coating. The 3D-printable material comprising the dopant material has the following optical properties when the temperature of the 3D-printable material comprising the dopant material is raised above a temperature variation T. c At a certain temperature, the optical properties irreversibly change from low-temperature optical properties to high-temperature optical properties. This change occurs at temperature T. c Within a first temperature range. During at least the first portion of the 3D printing phase, the first temperature T1 is lower than the varying temperature T. c Furthermore, during at least the second part of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c Therefore, in a particular embodiment, the present invention provides a method for producing 3D articles by fused deposition modeling, the method comprising a 3D printing stage comprising layer-by-layer deposition of an extrusion comprising a 3D-printable material to provide a 3D article comprising layers of the 3D-printable material, wherein the 3D article comprises layers of the 3D-printable material, wherein the method further comprises controlling a first temperature T1 of the 3D-printable material within a first temperature range, wherein the 3D-printable material comprises a dopant material, and the 3D-printable material comprising the dopant material has a temperature range where the temperature of the 3D-printable material comprising the dopant material increases above a change temperature T. c The optical properties irreversibly change from low-temperature optical properties to high-temperature optical properties, wherein the temperature of change is within a first temperature range. Specifically, in an embodiment, during at least a first portion of the 3D printing phase, the first temperature T1 is lower than the temperature of change T. c And during at least the second part of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c .

[0009] This method allows for the creation of optical effects distinct from those of the 3D-printed object. In principle, using a single type of material, one or more 3D-printed parts can be created with optical effects different from one or more other parts, even though the material composition can be substantially the same. This achieves a relatively simple 3D printing method, but also increases the controllability of the local material properties of the 3D-printed object.

[0010] Therefore, it is also desirable to provide a filament that can be used in the methods described herein. Accordingly, in one aspect of the invention, the invention provides a 3D-printable material, particularly a filament comprising the 3D-printable material, wherein the 3D-printable material comprises a (body) polymer, particularly a thermoplastic material, and a dopant material. This 3D-printable material, particularly this filament, can be extruded at temperatures below Tc, thereby maintaining its (low-temperature) optical properties, or extruded at temperatures above Tc, thereby changing its (low-temperature) optical properties (to high-temperature optical properties). In another aspect, the invention provides a filament comprising a first portion and a second portion, wherein one or more of the plurality of layers have low-temperature optical properties (when the temperature of the 3D-printed material comprising the dopant material is increased above the change temperature Tc). c The filament can irreversibly change to high-temperature optical properties, and one or more of the layers in the second part possess high-temperature optical properties. Specifically, this filament can be extruded at temperatures below the temperature at which the change occurs, but alternatively, one or more (the first part) can also be extruded at temperatures above the temperature at which the change occurs. c It is extruded at a certain temperature.

[0011] Below, we will first discuss some general aspects related to the principles governing changes in optical properties. We will then further discuss general aspects related to 3D printing.

[0012] Temperature control of 3D printable materials is often part of the 3D printing process because the material must be printable to be 3D printable. To do this, the 3D printable material can be introduced into a nozzle, heated, extruded from the nozzle, and deposited.

[0013] As will be further clarified below, 3D-printable materials (and therefore generally also 3D-printed materials) include thermoplastic materials. In embodiments, the thermoplastic material itself (i.e., without considering dopant materials) may be translucent, although this is not necessarily the case. As indicated herein, 3D-printable materials also include dopant materials. Thermoplastic materials are the host material with respect to dopant materials. Therefore, polymeric materials, especially thermoplastic materials, may also be indicated as "host material" and similar designations.

[0014] The transmittance of a light-transmitting material of one or more wavelengths (visible light) can be at least 80% / cm, such as at least 90% / cm, or even more particularly at least 95% / cm, such as at least 98% / cm, such as at least 99% / cm. This means, for example, that a 1 cm³ cubic piece of light-transmitting material, when vertically irradiated with radiation having a selected visible wavelength, will have a transmittance of at least 95%.

[0015] In this document, the value of transmittance specifically refers to transmittance without considering Fresnel losses (e.g., air) at the interface. Therefore, the term "transmittance" specifically refers to internal transmittance. Internal transmittance can be determined, for example, by measuring the transmittance of two or more bodies with different widths, across which the transmittance is measured. Based on such measurements, the contribution of Fresnel reflection losses and (therefore) the internal transmittance can then be determined. Therefore, in particular, the values ​​of transmittance indicated herein neglect Fresnel losses.

[0016] The term “wavelengths of interest” can specifically refer to one or more wavelengths in the visible light spectrum.

[0017] The terms “light” and “radiation” are used interchangeably herein unless the context clearly indicates that the term “light” refers only to visible light. The terms “light” and “radiation” can therefore refer to UV radiation, visible light, and IR radiation. In certain embodiments, particularly for lighting applications, the terms “light” and “radiation” refer to visible light. In this document, the term “visible light” specifically refers to light having wavelengths selected from the range of 380-780 nm.

[0018] 3D printable materials include doped materials. Doped materials can include one or more molecules (dopant molecules) and particles (dopant particles). Doped materials can also include host particles containing doped materials. Host particles can also be designated as doped materials.

[0019] Dopant materials can be dispersed molecularly in thermoplastic materials, such as organic dyes dispersed in thermoplastic materials. The term "organic dye" can refer to dyes with pigment functions or luminescent dyes (which may also have pigment functions in certain embodiments).

[0020] The dopant material can also be a particulate material, which can be dispersed in a thermoplastic material, such as quantum particles like quantum dots and / or quantum rods, metal flakes, etc. The dopant material can be provided as a polymer or aggregate of particulate dopant materials. The dopant material can also include polymer particles comprising molecules or particles. A release particle can be provided, comprising a coating, such as a polymer coating, covering the molecules or particles. For example, when the temperature is raised above the change temperature, the coating can be at least partially removed (due to melting or destruction, etc.), and the molecules or particles can be introduced into the surrounding (body) polymer. Therefore, in a particular embodiment, a 3D printable material can include a dopant material, and wherein the temperature of the 3D printable material including the dopant material is raised above the change temperature T. c At that time, molecules emerge from the dopant material.

[0021] 3D printable materials containing doped materials have the property that when the temperature of the 3D printable material containing doped materials is raised above the temperature change T... c The optical properties that irreversibly change from low-temperature optical properties to high-temperature optical properties, wherein the temperature of change is within a first temperature range.

[0022] In certain embodiments, the optical properties can be substantially applied to the 3D-printable material by the dopant material. This could be, for example, in the case of a luminescent dopant material in a transparent thermoplastic material or a reflective sheet in a transparent thermoplastic material. However, in other embodiments, the optical properties may be due to a combination of the thermoplastic material and the dopant material. For example, this could be when the thermoplastic material or the dopant material has a structuring effect on the dopant material or the thermoplastic material, respectively.

[0023] In embodiments, the dopant material may include polymer particles, which include luminescent materials comprising molecules capable of quenching luminescence. Above a critical temperature, the quenching molecules can penetrate the dopant particles, leading to quenching of luminescence. In embodiments, the particles may also contain molecules of a transparent material that can react with other colorless molecules contained in a transparent matrix (to provide colored molecules). Here, similarly, above a certain temperature, these molecules mix, resulting in a colored appearance. The critical temperature in these embodiments may be a temperature related to the glass transition temperature of the polymer material surrounding the molecules and / or particles.

[0024] Therefore, the phrase “including 3D-printable materials containing doped materials that have optical properties” and similar phrases can therefore refer to optical properties that change due to variations in the doped material, optical properties that change due to variations in the distribution of the doped material, optical properties that change due to variations in the polymer host material as a function of the reaction between the doped material and the polymer host material, optical properties that change due to the reaction between the doped material and another doped material, and so on.

[0025] Therefore, in the embodiments, the dopant material can have variable optical properties. Alternatively or additionally, in the embodiments, the combination of the polymer (body) material and the dopant material can have variable optical properties. An example of the former could be a change in the color of the dopant material. An example of the latter could be a polymer body material having a color or a specific transparency that changes when the dopant material is released and, for example, reacts with the polymer material.

[0026] Optical properties are particularly temperature-dependent. Therefore, optical properties at a first temperature may differ from those at a second temperature. For example, color may change, transmittance may change, and luminosity may change. In particular, changes as a function of temperature are irreversible. Therefore, optical properties can be set to their high-temperature properties when a certain temperature is exceeded. Changes in optical properties may be due to degradation, conformational changes, migration of particulate materials (increased uniformity with increasing temperature, etc.). In specific embodiments, optical properties are selected from the group consisting of reflectance, transmittance, luminosity, absorptivity, and color. One or more of such optical properties may change with temperature. Alternatively, in embodiments with temperature, one or more of such optical properties change, while one or more of other such optical properties remain unchanged.

[0027] For example, in one embodiment, when the temperature is increased (above the changing temperature), at least some of the dopant material may oxidize or degrade. For example, aluminum may be oxidized to aluminum oxide.

[0028] For example, when the temperature is increased (above the changing temperature), the luminescent molecules (such as dyes) or (luminescent) quantum particles may be distributed more evenly, which may lead to increased luminescence.

[0029] For example, when the temperature is increased (above the changing temperature), the particulate dopant may decompose into smaller particles.

[0030] For example, when the temperature is increased (above the changing temperature), the (particulate) dopant material may be bleached.

[0031] For example, when the temperature is increased (above the changing temperature), particulate doped materials may change shape (e.g., bend or shrink).

[0032] For example, when the temperature is increased (above the changing temperature), quenching molecules may react with luminescent molecules, which may be due to increased diffusion or release from the (particulate) polymer host material.

[0033] As with any 3D printing method, temperature can be controlled in any way; temperature control can be used to control the 3D printing process and also to control optical properties. Therefore, in particular, dopant materials and / or thermoplastic materials can be selected, where changes in optical properties are also within the range of the 3D printing temperature (of the thermoplastic material). Thus, in embodiments, the method may further include controlling a first temperature T1 of the 3D printable material within a first temperature range, wherein the temperature T varies. c Within the first temperature range.

[0034] Generally, it may be desirable to practically utilize the possibility of controlling optical properties. Therefore, in embodiments, a portion of a 3D-printed article may have low-temperature optical properties and a portion of a 3D-printed article may have high-temperature optical properties. Thus, in a particular embodiment, during at least a first portion of the 3D printing phase, a first temperature T1 is lower than the varying temperature T. c Furthermore, during at least the second part of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c The term "below the temperature of change T" c The term "first temperature T1" and similar terms can also be simply referred to as "low temperature". The term "above the changing temperature T1" is used in conjunction with the term "temperature above the temperature change T1". c The term "first temperature T1" and similar terms can also be abbreviated as "high temperature". The phrase "during at least the first part of the 3D printing phase, the first temperature T1 is lower than the changing temperature T" means that during this phase, the temperature T1 is lower than the changing temperature T. c Furthermore, during at least the second part of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c "And similar phrases can refer to any order of low and high temperatures. Furthermore, during 3D printing, there can be multiple changes between low and high temperatures, or between high and low temperatures."

[0035] Note that, in certain embodiments, during 3D printing, essentially throughout the entire 3D printing phase, the printable material being 3D printed may have been heated above a temperature variation T. c However, in other specific embodiments, during 3D printing, essentially throughout the entire 3D printing phase, the printable material being 3D printed may have been treated below a varying temperature T. c However, specifically, during at least the first part of the 3D printing phase, the initial temperature T1 is lower than the changing temperature T. c Furthermore, during at least the second part of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c As indicated above, the first part of the 3D printing stage may precede the second part of the 3D printing stage, but the second part of the 3D printing stage may also precede the first part of the 3D printing stage. Furthermore, the terms "first part" and "second part" may each (independently) refer to multiple different first parts and second parts.

[0036] Keep 3D printable materials below temperature variations during storage and transport via 3D printer. c It is likely the most effective method, and only when it is necessary to deposit 3D-printed materials with high-temperature optical properties, by heating the nozzle above a varying temperature T. c This method offers the greatest flexibility and allows for selective heating to varying temperatures T above or below the potentially highest point.c Therefore, in an embodiment, the method may include performing a 3D printing stage using a fused deposition modeling 3D printer, the fused deposition modeling 3D printer including a print head having a printer nozzle, wherein the method includes controlling a first temperature T1 of the 3D-printable material within the printer nozzle. Therefore, the print head may also include a controllable heating element for heating the 3D-printable material in the nozzle. Thus, in an embodiment, the 3D-printable material is not heated above the varying temperature throughout the 3D printer, and only within the print head can the 3D-printable material be heated above the varying temperature.

[0037] Many possible thermoplastic materials are described below. However, among other things, good results have been obtained using thermoplastic materials based on polyethylene or polypropylene. In specific embodiments, the 3D-printable material includes one or more of polyethylene (PE), high-density polyethylene (HDPE), polypropylene (PP), and high-density polypropylene (HDPP). In alternative (or additional) specific embodiments, the 3D-printable material includes one or more of polyethylene (PE), low-density polyethylene (LDPE), polypropylene (PP), and low-density polypropylene (HDPP). In further embodiments, the 3D-printable material includes one or more copolymers of the above polymers. In even further embodiments, the 3D-printable material includes copolymers of PP. Furthermore, in specific embodiments, the printable material includes a dopant material in the range of 0.5-30 vol.%, such as particularly 1-20 vol.%, or at least 2 vol.%. However, this can depend on the type of dopant material.

[0038] As indicated above, different types of dopants, such as molecules or particles, can be present. Dopants can affect one or more of the reflectance, transmittance, luminosity, absorptivity, and color of 3D-printable materials, thereby affecting one or more of the reflectance, transmittance, luminosity, absorptivity, and color of the 3D-printed material. Reflectance can vary from a lower value to a higher value, and vice versa. Transmittance can vary from a lower value to a higher value, and vice versa. Luminosity can vary from a lower intensity to a higher intensity, and vice versa (under illumination of the same intensity at the same wavelength). Absorbency can vary from a lower value to a higher value, and vice versa. Color can vary from a lower value to a higher value, and vice versa, in one or more of hue, saturation, chroma, brightness, and luminance. In particular, the lowest possible lower value can be at least 10% lower than the highest possible higher value, such as at least 20% lower, such as at least 30% lower, and especially at least 50% lower. The term "lowest possible lower value" refers to a value achievable by a 3D printing method at a relatively low temperature within a selected first temperature range. The term "highest possible higher value" refers to the value that can be achieved by a 3D printing method at a relatively high temperature within a selected first temperature range, and when the 3D printable material can be exposed to this temperature for at least approximately 10 seconds (within the print head, particularly within the nozzle).

[0039] In this embodiment, the 3D printable material can be exposed to high temperatures within the printhead. The residence time within the printhead can be particularly long enough to trigger a transformation (to high-temperature optical properties). The residence time can also depend on how much the temperature exceeds Tc. If the temperature is significantly higher than Tc, the residence time may be much shorter. This should be understood by those skilled in the art.

[0040] Therefore, in an embodiment, the method may further include: exposing a 3D printable portion to a temperature below a varying temperature T. c The first temperature T1 is reached, and the 3D printable material is 3D printed, and a portion of the 3D printable material is exposed to a temperature higher than the changing temperature T. c The second temperature T2 is then reached, and the 3D-printable material is 3D printed. As indicated above, the order can be different, and there can be one or two such stages.

[0041] Changes in optical properties may be due to conformational changes in, for example, doped materials or thermoplastic materials. Changes in optical properties may be alternatively or additionally attributed to, for example, degradation of doped materials. Changes in optical properties may be alternatively or additionally the result of reactions or mixing of two or more materials (such as molecules). Changes in optical properties may be alternatively or additionally attributed to, for example, decomposition of doped materials. Changes in optical properties may be alternatively or additionally attributed to variations in the distribution of doped materials.

[0042] Good results were obtained using reflective particles. Experiments showed that these particles lose their reflective properties at specific temperatures. Therefore, dopant materials include polymer sheet-like particles with a metallic coating.

[0043] In a further specific embodiment, the dopant material comprises polyethylene terephthalate (PET) flake particles with an aluminum coating. In this embodiment, the PET may be biaxially oriented.

[0044] The thickness of the carrier polymer (sheet-like particles), such as PET, can range from 10 to 100 μm. The thickness of the aluminum coating can be selected from, for example, a range of 10 to 60 nm.

[0045] Therefore, in certain embodiments, the dopant material includes flash particles.

[0046] In embodiments, the dopant material may comprise sheet-like particles having a particle length (L1) and a particle height (L2), wherein the aspect ratio of L1 / L2 is at least 5, such as at least 10, such as in the range of 10-1000. It appears useful when these sheets are at least partially aligned in the layers. Therefore, in a particular embodiment, the dopant material may comprise sheet-like particles having a particle length (L1) and a particle height (L2), wherein the aspect ratio of L1 / L2 is at least 5, and wherein the method comprises printing one or more layers of 3D-printed material having a layer height (H), wherein in the embodiment the layer height (H) is less than the particle length (L2). This lower layer height can be particularly useful when the layers are stacked. In embodiments, the layer height (H) is greater than the particle length (L2) when the layers are adjacent (i.e., adjacent layers each have substantially the same height (H)).

[0047] As indicated above, changes in optical properties can be attributed to variations in the distribution of dopant materials. For example, pigments can be provided as aggregates of particles, which may have a relatively small effect on the color of the 3D-printable material (as it is only available at one or more specific locations). Upon heating, the pigment may migrate or diffuse through the polymerized material and alter the color of the 3D-printable material. In this way, the color may change. Alternatively, luminescent materials can be provided as aggregates of particles, which may have relatively low luminescence due to quenching of luminescence (e.g., via a reabsorption process); this may apply to luminescent materials exhibiting concentration quenching. Upon heating, the luminescent material may migrate or diffuse through the material, thereby reducing concentration quenching. In this way, the luminescent properties may change. Variations in local concentration can affect not only luminescence intensity but also, in certain embodiments, the spectral power distribution of the luminescent material. For example, some materials are known to reabsorb at higher concentrations and also exhibit a redshift at higher concentrations. When the concentration is locally reduced, reabsorption may decrease, and a blueshift may be perceived. Suitable luminescent materials can be organic luminescent dyes, such as perylene luminescent dyes, like Lumogen (e.g., BASF). Suitable dopant materials can be polymer particles, such as PET, or carriers or surrounds organic light-emitting molecules, such as perylene-based organic light-emitting materials (such as Lumogens, as BASF). Therefore, in certain embodiments, the 3D-printable material may include a non-uniformly distributed dopant material, and the temperature of the 3D-printable material including the dopant material may rise above the temperature change T. c At this time, the uniformity of the dopant material increases. This increase in uniformity may be specifically attributed to the increased mobility of the dopant material. In some other specific embodiments, the 3D-printable material may include dopant materials, such as polymer particles having a high concentration of luminescent particles therein, and wherein the temperature of the 3D-printable material including the dopant material increases above the temperature change T. c At this time, the uniformity of the luminescent molecules and the polymer matrix (doped material) increases; the luminescent particles can be distributed on the polymer (main) material.

[0048] As indicated above, the present invention provides a method for producing 3D articles by fused deposition modeling, the method comprising a 3D printing stage comprising depositing layer-by-layer an extrusion comprising a 3D-printable material to provide a 3D article comprising layers of 3D-printed material on a receiver article. Other aspects related to these features are also set forth below.

[0049] As indicated above, the method includes depositing 3D-printable material during the printing stage. In this document, "3D-printable material" refers to the material to be deposited or printed, and "3D-printed material" refers to the material obtained after deposition. These materials may be substantially the same, as 3D-printable material may specifically refer to material at high temperatures in the print head or extruder, while 3D-printed material refers to the same material but in a later stage during deposition. The 3D-printable material is printed as a filament and deposited as is. The 3D-printable material can be provided as a filament or can be formed into a filament. Therefore, regardless of the starting material applied, filaments including 3D-printable material are provided by the print head and 3D printed. The term "extrudate" can be used to define 3D-printable material downstream of the print head but not yet deposited. The latter is indicated as "3D-printed material." In fact, extrudate includes 3D-printable material because it has not yet been deposited. After the deposition of 3D-printable material or extrudate, the material is therefore indicated as 3D-printed material. Essentially, these materials are the same material because the thermoplastic material upstream of the printhead, downstream of the printhead, and during deposition is essentially the same material.

[0050] In this document, the term "3D printable material" may also refer to "printable material". The term "polymer material" may refer to a blend of different polymers in the embodiments, but may also refer to a single polymer type that substantially has different polymer chain lengths. Therefore, the terms "polymer material" or "polymer" may refer to a single type of polymer, but may also refer to multiple different polymers. The term "printable material" may refer to a single type of printable material, but may also refer to multiple different printable materials. The term "printing material" may refer to a single type of printing material, but may also refer to multiple different printing materials.

[0051] Therefore, the term "3D printable material" can also refer to a combination of two or more materials. Generally, these (polymer) materials have a glass transition temperature T0. g and / or melting temperature T m The 3D printable material is heated by the 3D printer to a temperature at least its glass transition temperature, and generally at least its melting temperature, before it leaves the nozzle. Therefore, in one specific embodiment, the 3D printable material includes materials having a glass transition temperature (T0). g ) and / or melting point (T m The thermoplastic polymer is used, and the printer head action includes heating the 3D printable material to above its glass transition temperature, and if it is a semi-crystalline polymer above its melting temperature. In yet another embodiment, the 3D printable material includes materials having a melting point (T0).m The process involves heating the (thermoplastic) polymer to be deposited onto the receiver article to a temperature at least its melting point. The glass transition temperature is generally different from the melting temperature. Melting is a transition that occurs in crystalline polymers. Melting occurs when polymer chains break away from their crystalline structure and become a disordered liquid. The glass transition is a transition that occurs in amorphous polymers; that is, the polymer chains are not arranged in an ordered crystalline pattern but are dispersed in any way, even if they are in a solid state. Polymers can be amorphous, essentially having a glass transition temperature rather than a melting temperature, or they can be (semi-)crystalline, generally having both a glass transition temperature and a melting temperature, generally the latter being greater than the former. The glass transition temperature can be determined, for example, by differential scanning calorimetry (DSC). The melting point or melting temperature can also be determined by DSC.

[0052] As indicated above, the present invention therefore provides a method comprising providing a filament of a 3D-printable material and printing the 3D-printable material on a substrate during a printing phase to provide the 3D article.

[0053] Specifically, materials eligible for 3D printing can be selected from the group consisting of metals, glass, thermoplastic polymers, silicone resins, etc. In particular, 3D printable materials include (thermoplastic) polymers selected from the group consisting of: ABS (acrylonitrile butadiene styrene), nylon (or polyamide), cellulose acetate (or cellulose), PLA (polylactic acid), terephthalates (such as PET polyethylene terephthalate), acrylics (polymethyl acrylate, plexiglass, polymethyl methacrylate, PMMA), polypropylene (or polypropylene), polycarbonate (PC), polystyrene (PS), PE (such as expanded high-impact polyethylene (or polyethylene), low-density (LDPE) high-density (HDPE)), PVC (polyvinyl chloride), thermoplastic elastomers such as copolyester-based elastomers, polyurethane elastomers, polyamide elastomers, polyolefin-based elastomers, styrene-based elastomers, etc. Optionally, 3D printable materials include those selected from the group consisting of: urea-formaldehyde, polyester resins, epoxy resins, melamine-formaldehyde, thermoplastic elastomers, etc. Optionally, 3D printable materials include those selected from the group consisting of polysulfones. Elastomers, particularly thermoplastic elastomers, are of particular interest because they are flexible and can help obtain relatively more flexible filaments incorporating thermally conductive materials. Thermoplastic elastomers may include one or more of the following: styrene block copolymers (TPS(TPE-s)), thermoplastic polyolefin elastomers (TPO(TPE-o)), thermoplastic vulcanizates (TPV(TPE-v or TPV)), thermoplastic polyurethanes (TPU)(TPU)), thermoplastic copolyesters (TPC(TPE-E)), and thermoplastic polyamides (TPA(TPE-A)).

[0054] Suitable thermoplastic materials, such as those also mentioned in WO2017 / 040893, may include one or more of the following: polyacetals (e.g., polyoxyethylene and polyoxymethylene), poly(C1-6 alkyl)acrylates, polyacrylamide, polyamides (e.g., aliphatic polyamides, polyphthalamides, and polyarylamides), polyamide-imide, polyanhydride, polyarylate, polyarylene ether (e.g., polyphenylene ether), polyarylene sulfide (e.g., polyphenylene sulfide), polyarylsulfone (e.g., polyphenylene sulfone), polybenzothiazole, polybenzoxazole, polycarbonate (including polycarbonate copolymers such as polycarbonate-siloxane, polycarbonate-ester, and polycarbonate-ester-siloxane), polyester (e.g., polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyarylene ether) and polyester copolymers such as polyester ether), polyetheretherketone, polyetherimide (including copolymers such as poly... The following are examples of thermoplastic polymers: polyetherimide-siloxane copolymers, polyetherketoneketone, polyetherketone, polyethersulfone, polyimide (including copolymers such as polyimide-siloxane copolymers), poly(C1-6 alkyl) methacrylate, polymethacrylamide, polynorbornene (including copolymers containing norbornene units), polyolefins (e.g., polyethylene, polypropylene, polytetrafluoroethylene and their copolymers, such as ethylene-α-olefin copolymers), polyoxadiazole, polyoxymethylene, polyphthalate, polysilazane, polysiloxane, polystyrene (including copolymers such as acrylonitrile-butadiene-styrene (ABS) and methyl methacrylate-butadiene-styrene (MBS)), polysulfides, polysulfonamides, polysulfonates, polysulfones, polysulfides, polytriazines, polyureas, polyurethanes, polyvinyl alcohol, polyvinyl esters, polyvinyl ether, polyvinyl halide, polyvinyl ketone, polyvinyl sulfide, polyvinylidene fluoride, etc., or combinations comprising at least one of the aforementioned thermoplastic polymers. Examples of polyamides may include, but are not limited to, the synthesis of linear polyamides, such as nylon-6,6; nylon-6,9; nylon-6,10; nylon-6,12; nylon-11; nylon-12 and nylon-4,6, preferably nylon-6 and nylon-6,6, or combinations comprising at least one of the foregoing. Polyurethanes that can be used include aliphatic, alicyclic, aromatic, and polycyclic polyurethanes, including those described above. Also useful are polyacrylates (C... 1-6 alkyl) and polymethyl acrylate (C 1-6Alkyl groups, including polymers of, for example, methyl acrylate, ethyl acrylate, acrylamide, methacrylic acid, methyl methacrylate, n-butyl acrylate, and ethyl acrylate. In embodiments, polyolefins may include one or more of the following: polyethylene, polypropylene, polybutene, polymethylpentene (and copolymers thereof), polynorbornene (and copolymers thereof), poly-1-butene, poly(3-methylbutene), poly(4-methylpentene), and copolymers of ethylene with propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 1-octadecene.

[0055] In certain embodiments, the 3D-printable material (and the 3D-printed material) includes one or more of the following: polycarbonate (PC), polyethylene (PE), high-density polyethylene (HDPE), polypropylene (PP), polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), polysulfone (PSU), polyphenylene sulfide (PPS), and semi-crystalline polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), polystyrene (PS), and styrene-acrylic acid copolymer (SMMA).

[0056] The first temperature range can have the lowest temperature at which 3D-printable materials can be extruded. In an embodiment, this can be approximately the glass transition temperature. Those skilled in the art of 3D (FDM) printing will know the highest temperature within the first temperature range. The first temperature range can be a range in which 3D-printable materials can be suitably extruded. The temperature range can be, for example, approximately 20-100°C, such as 20-50°C. For example, PP can be extruded, for example, at a temperature selected from 173-225°C (i.e., approximately the glass transition temperature + approximately 50°C), although other temperatures are also possible.

[0057] The term 3D printable materials is further clarified below, but specifically refers to thermoplastic materials, optionally including additives, which have a volume percentage of up to about 60%, particularly up to about 30 vol.%, such as up to 20 vol.%.% (the percentage of additives relative to the total volume of thermoplastic materials and additives).

[0058] Therefore, in the embodiments, the printable material may include two phases. The printable material may include a printable polymeric material phase, particularly a thermoplastic material (see also below), and specifically, this phase is a substantially continuous phase (“host material” or “polymer host material”). Additives may be present in this continuous phase of the thermoplastic polymer, such as one or more of the following: antioxidants, heat stabilizers, light stabilizers, UV stabilizers, UV absorbers, near-infrared absorbers, infrared absorbers, plasticizers, lubricants, mold release agents, antistatic agents, antifogging agents, antibacterial agents, colorants, laser marking additives, surface effect additives, radiation stabilizers, flame retardants, and anti-drip agents. The additives may have useful properties selected from optical, mechanical, electrical, thermal, and mechanical properties (see also above).

[0059] In embodiments, printable materials may include particulate materials, i.e., particles embedded in printable polymer materials, which form a substantially discontinuous phase. Particularly in applications for reducing the coefficient of thermal expansion, the amount of particles in the total mixture relative to the total volume of the printable material (including (anisotropically conductive) particles) is particularly no more than 60 vol.%. For optical and surface-related effects, the amount of particles in the total mixture relative to the total volume of the printable material (including particles) is equal to or less than 20 vol.%, such as reaching 10 vol.%. Therefore, 3D-printable materials specifically refer to a continuous phase of a basic thermoplastic material in which other materials such as particles may be embedded. Similarly, 3D-printable materials specifically refer to a continuous phase of a basic thermoplastic material in which other materials such as particles are embedded. The particles may include one or more additives as defined above. Therefore, in embodiments, 3D-printable materials may include particulate additives.

[0060] Printable material is printed onto a receiver item. Specifically, the receiver item can be a build platform, or can be composed of a build platform. The receiver item can also be heated during 3D printing. However, the receiver item can also be cooled during 3D printing.

[0061] The phrase "printing on a receiver article" and similar phrases include: printing directly on a receiver article, or printing on a coating on a receiver article, or printing on 3D-printed material previously printed on a receiver article. The term "receiver article" can refer to a printing platform, print bed, substrate, support, build plate, or build platform, etc. The term "substrate" may also be used instead of the term "receiver article." The phrase "printing on a receiver article" and similar phrases also include printing on a separate substrate, or printing on a separate substrate included in the following: a printing platform, print bed, support, build plate, or build platform, etc. Therefore, the phrase "printing on a substrate" and similar phrases particularly include: printing directly on a substrate, or printing on a coating on a substrate, or printing on 3D-printed material previously printed on a substrate. Hereinafter, the term substrate is further used, which can refer to a printing platform, print bed, substrate, support, build plate, or build platform, or a separate substrate on or included in the listed items.

[0062] Printable material is deposited layer by layer to create a 3D printed article (during the printing phase). The 3D printed article may exhibit a characteristic ribbed structure (derived from the deposited filaments). However, an additional phase, such as a final phase, may be performed after the printing phase. This phase may include: removing the printed article from the receiver article and / or one or more post-processing actions. One or more post-processing actions may be performed before removing the printed article from the receiver article, and / or after removing the printed article from the receiver article. For example, post-processing may include one or more of the following: polishing, coating, adding functional parts, etc. Post-processing may include smoothing the ribbed structure, which can produce a generally smooth surface.

[0063] Furthermore, the present invention relates to software products that can be used to perform the methods described herein. Therefore, in another aspect, the present invention also provides a computer program product that, when functionally coupled to or executed on a computer included with a fused deposition modeling 3D printer, is capable of implementing the methods described herein. Thus, in one aspect, the present invention provides a software product that, when executed on a computer, is capable of implementing (one or more embodiments) of the method described herein (for producing 3D articles by fused deposition modeling).

[0064] The method described herein provides 3D printed articles. Therefore, in another aspect, the present invention also provides a 3D printed article obtainable using the method described herein. In another aspect, a 3D printed article obtainable using the method described herein is provided. Specifically, the present invention provides a 3D article comprising a 3D-printed material. As indicated above, the 3D article comprises multiple layers of the 3D-printed material. Furthermore, the 3D-printed material comprises a thermoplastic host material and a dopant material in the range of 1-20 vol.%, wherein the dopant material comprises polymer flake particles with a metallic coating. As indicated above, the 3D-printed material comprising the dopant material has the property that when the temperature of the 3D-printed material comprising the dopant material increases above a temperature change T... c The optical properties irreversibly change from low-temperature optical properties to high-temperature optical properties. At least the first portion of one or more of the multiple layers possesses low-temperature optical properties (particularly when the temperature of the 3D-printed material, including doped materials, rises above the temperature of the change, T). c When [the temperature changes irreversibly], it can transform into high-temperature optical properties. Furthermore, at least a second portion of one or more of the multiple layers possesses high-temperature optical properties. Therefore, the present invention specifically provides, in embodiments, a 3D article comprising a 3D-printed material, wherein the 3D article comprises multiple layers of the 3D-printed material, wherein the 3D-printed material includes a dopant material, and the 3D-printed material including the dopant material has the property that when the temperature of the 3D-printed material including the dopant material increases above a change temperature T... c Optical properties that irreversibly change from low-temperature optical properties to high-temperature optical properties, wherein at least the first portion of one or more of the multiple layers has low-temperature optical properties (when the temperature of the 3D-printed material including the dopant material is raised above the change temperature T). c When, it can irreversibly change to high-temperature optical properties) and at least the second part of one or more of the multiple layers has high-temperature optical properties.

[0065] Therefore, the phrase "3D-printed materials may include doped materials, which have the property that when the temperature of the 3D-printed material including the doped material is increased above the temperature change T" is also present. c The phrase "optical properties that irreversibly change from low-temperature optical properties to high-temperature optical properties" in an embodiment can refer to a 3D-printed material in which a first portion has low-temperature optical properties and a second portion has high-temperature optical properties. However, in a particular embodiment, the phrase "3D-printed material may include doped material, which has the property that when the temperature of the 3D-printed material including the doped material is increased above the temperature of change T" may be used. cThe phrase "optical properties that irreversibly change from low-temperature optical properties to high-temperature optical properties" in the embodiments may refer to 3D-printed materials that only possess low-temperature optical properties. Alternatively, the phrase "3D-printed materials may include doped materials that have the property that changes irreversibly from low-temperature optical properties to high-temperature optical properties" may refer to 3D-printed materials that, when the temperature of the 3D-printed material including the doped material is increased above the temperature of the change T c The phrase "optical properties that irreversibly change from low-temperature optical properties to high-temperature optical properties" in the embodiments may refer to 3D-printed materials that only possess high-temperature optical properties. However, generally speaking, 3D-printed materials include a first portion of 3D-printed material with low-temperature optical properties and a second portion of 3D-printed material with high-temperature optical properties. However, when the temperature rises above the temperature of change T... c At that time, the first part can be transformed into the second part.

[0066] 3D printed articles may include multiple layers stacked on top of each other, i.e., stacked layers. The width (thickness) and height of the (individually 3D printed) layers may, for example, be selected from the range of 100-5000 μm in the embodiments, such as 200-2500 μm, and the height is generally smaller than the width. For example, the ratio of height to width may be equal to or less than 0.8, such as equal to or less than 0.6.

[0067] The layers can be core-shell layers or can consist of a single material. Within the layers, changes can also occur in the composition; for example, when applying a core-shell printing process, during printing, it changes from printing the first material (instead of printing the second material) to printing the second material (instead of printing the first material).

[0068] At least a portion of a 3D printed item may include a coating.

[0069] Some specific embodiments related to 3D printed articles have been illustrated below in the discussion of the method. These specific embodiments related to 3D printed articles will now be discussed in more detail.

[0070] As indicated above, in specific embodiments, the 3D-printed material may include one or more of the following: polyethylene (PE), low-density polyethylene (LDPE), polypropylene (PP), and low-density polypropylene (LDPP), as well as copolymers of two or more of these. In particular, low-density variants may have higher transparency than high-density variants. As indicated above, thermoplastic polymers (without dopants) may be translucent or even substantially transparent.

[0071] The dopant material includes polymer sheet-like particles with a metallic coating. More specifically, the dopant material may include polyethylene terephthalate sheet-like particles with an aluminum coating.

[0072] In a specific embodiment, the sheet-like particles may have a particle length (L1) and a particle height (L2), wherein the aspect ratio of L1 / L2 is at least 5, such as at least 10. Furthermore, given the alignment of the sheet-like particles, it may be desirable for each layer of one or more 3D-printed materials to have a layer height (H), wherein in the embodiments the layer height (H) is less than the particle length (L2), particularly where the layers are stacked. When these layers are not stacked, but when these layers are configured to be adjacent to each other (e.g., to form, for example, parallel-arranged layers—3D-printed layers), the layer height (H) may particularly be greater than the particle length (L2).

[0073] The 3D-printed material includes a thermoplastic host material for carrying the dopant material. In a specific embodiment, the thermoplastic host material of the first and second parts is the same, for example, both comprising PP or PE. Furthermore, in a specific embodiment, the printing material includes a dopant material in the range of 1-20 vol.%. Specifically, the volume percentage of the dopant material in the first and second parts is the same (because they may originate from the same filament). Since the different parts can have different optical properties, this can be visible to the user. For example, transmittance, absorptivity, luminosity, etc., may differ. Therefore, in a specific embodiment, the wavelength-dependent transmittance and / or wavelength-dependent reflectance of the first and second parts differ when vertically illuminated with wavelengths in the visible wavelength range. As indicated above, in the embodiments, the lowest possible lower value can be at least 10% lower than the highest possible higher value, such as at least 20% lower, for example at least 30% lower, and particularly at least 50% lower (than the highest possible higher value).

[0074] Alternatively or additionally, in an embodiment, one of the first and second portions has a more non-uniformly distributed dopant material than the other. As indicated above, this may also result in different optical properties between the first and second portions.

[0075] The 3D-printed articles obtained (using the methods described herein) can be functional in themselves. For example, 3D-printed articles can be lenses, collimators, reflectors, etc. The resulting 3D articles can (alternatively) be used for decorative or artistic purposes. 3D-printed articles may include or be provided with functional components. In particular, the functional components can be selected from the group consisting of optical components, electrical components, and magnetic components. The term "optical component" specifically refers to components with optical functionality, such as lenses, mirrors, light-transmitting elements, filters, etc. The term optical component can also refer to a light source (such as an LED). The term "electronic component" can refer, for example, to integrated circuits, PCBs, batteries, drivers, and can also refer to light sources (since light sources can be considered both optical and electronic components). The term magnetic component can refer, for example, to magnetic connectors, coils, etc. Alternatively or additionally, functional components can include thermal components (e.g., electrical components configured to cool or heat). Thus, functional components can be configured to generate or remove heat, etc.

[0076] As indicated above, 3D printed articles can be used for various purposes. Among these, 3D printed articles can be used for lighting. Therefore, in another aspect, the invention also provides a lighting device that includes a 3D article as defined herein. In a specific aspect, the invention provides a lighting system comprising (a) a light source configured to provide (visible) light and (b) a 3D article as defined herein, wherein the 3D article can be configured as one or more of: (i) at least a portion of a housing, (ii) at least a portion of a wall of an illumination chamber, and (iii) a functional component, wherein the functional component may be selected from optical components, support members, electrically insulating components, conductive components, thermally insulating components, and thermally conductive components. Therefore, in a specific embodiment, the 3D article can be configured as one or more of: (i) at least a portion of a housing of a lighting device, (ii) at least a portion of a wall of an illumination chamber, and (iii) an optical element. Because it can provide a relatively smooth surface, the 3D printed article can be used as a mirror or lens, etc. In an embodiment, the 3D printed article can be configured to provide shadows. The device or system may include a plurality of different 3D printed articles with different functionalities.

[0077] For a light source, the spectral and / or spatial light distribution of light reflected, transmitted, and / or scattered by different parts of a 3D-printed article (i.e., the first and second parts of the 3D-printed material) may differ. Therefore, utilizing high-temperature or low-temperature optical properties can create different effects, which may be useful and / or desirable for lighting devices.

[0078] Returning to the 3D printing process, a specific 3D printer can be used to provide the 3D printed articles described herein. Therefore, in another aspect, the present invention also provides a fused deposition modeling (FDM) 3D printer, comprising (a) a print head including a printer nozzle, and (b) a 3D printable material supply device configured to supply 3D printable material to the print head, wherein the FDM 3D printer is configured to supply said 3D printable material, and wherein the temperature of the printer nozzle can be controlled. For this purpose, the 3D printer may include a heating element and a control system configured to control the heating element, wherein the heating element is specifically configured to heat the 3D printable material in the nozzle. For example, the print head may include a heating element.

[0079] A printer nozzle may include a single opening. In other embodiments, the printer nozzle may be core-shell type with two (or more) openings. The term "printer head" may also refer to multiple (different) printer heads; therefore, the term "printer nozzle" may also refer to multiple (different) printer nozzles.

[0080] A 3D-printable material supply device can supply a filament comprising 3D-printable material to a print head, or it can supply the 3D-printable material itself, while the print head creates a filament comprising the 3D-printable material. Therefore, in an embodiment, the present invention provides a fused deposition modeling 3D printer comprising (a) a print head including a print nozzle, and (b) a filament supply device configured to supply a filament comprising 3D-printable material to the print head, wherein the fused deposition modeling 3D printer is configured to supply the 3D-printable material to a substrate, and wherein the temperature of the print nozzle can be controlled. For this purpose, the 3D printer may include a heating element and a control system configured to control the heating element, wherein the heating element is specifically configured to heat the 3D-printable material in the nozzle. For example, the print head may include a heating element.

[0081] Specifically, the 3D printer includes a controller (or is functionally coupled to a controller), which is configured to perform the methods described herein in a control mode (or “operation mode”). In addition to the term “controller,” the term “control system” may also be used (see above, for example).

[0082] A system, apparatus, or device may perform actions in a “mode,” “operating mode,” or “mode of operation.” Similarly, in a method, actions, stages, or steps may be performed in a “mode,” “operating mode,” or “mode of operation.” The term “mode” may also refer to “control mode.” This does not preclude the system, apparatus, or device from being adapted to provide another control mode or multiple other control modes. Likewise, this does not preclude the possibility of performing one or more other modes before and / or after performing this mode.

[0083] However, in embodiments, a control system may be available that is adapted to provide at least a control mode. If other modes are available, the selection of such a mode can be performed specifically via a user interface; however, other options (e.g., performing modes depending on sensor signals or a (time) scheme) are also possible. In embodiments, an operating mode may also refer to a system, apparatus, or device that can only operate in a single operating mode (i.e., "on," without further adjustability).

[0084] The terms “3D printer,” “FDM printer,” or “printer” can be used instead of “Fused Deposition Modeling (FDM) 3D printer.” Printer nozzles may also be indicated as “nozzle” or sometimes as “extruder nozzle.” Attached Figure Description

[0085] Embodiments of the invention will now be described by way of example only with reference to the accompanying schematic diagrams, wherein corresponding reference numerals indicate corresponding parts, and wherein:

[0086] Figures 1a-1c schematically depict some general aspects of embodiments of 3D printers and 3D-printed materials;

[0087] Figures 2a-2f schematically depict some aspects of embodiments of the particles, some of which are depicted for reference purposes;

[0088] Figures 3a-3b schematically depict further aspects of the invention; and

[0089] Figure 4 The lamp or lighting device is depicted schematically.

[0090] Figure 5 An example of a dollar-shaped sheet is shown;

[0091] Figures 6a-6f schematically depict some aspects and embodiments.

[0092] The diagram is not necessarily drawn to scale. Detailed Implementation

[0093] Figure 1a schematically depicts some aspects of a 3D printer. Reference numeral 500 indicates a 3D printer. Reference numeral 530 indicates a functional unit configured for 3D printing—particularly FDM 3D printing; this reference numeral may also indicate a 3D printing stage unit. Here, only the printer head for providing 3D-printed material, such as an FDM 3D printer head, is schematically depicted. Reference numeral 501 indicates a printer head. The 3D printer of the present invention may in particular include multiple printer heads (see below). Reference numeral 502 indicates a printer nozzle. The 3D printer of the present invention may in particular include multiple printer nozzles, but other embodiments are also possible. Reference numeral 320 indicates a filament of printable 3D-printable material (as shown above). For clarity, not all features of the 3D printer are depicted, only those particularly relevant to the present invention are depicted (see also below). Reference numeral 321 indicates the extrudate (of the 3D-printable material 201).

[0094] 3D printer 500 is configured to generate 3D article 1 by layer-by-layer deposition on receiver article 550, which in embodiments may be at least temporarily cooled, comprising multiple layers 322, wherein each layer 322 includes a 3D printable material 201, such as having a melting point T. m 3D printable material 201 can be deposited on substrate 1550 (during the printing stage). Through deposition, 3D printable material 201 has become 3D printed material 202. 3D printable material 201 escaping from nozzle 502 is also indicated as extrudate 321. Reference numeral 401 indicates thermoplastic material.

[0095] The 3D printer 500 can be configured to heat the filament 320 material upstream of the printer nozzle 502. This can be accomplished, for example, by a device that includes one or more of extrusion and / or heating functions. Such a device is indicated by reference numeral 573 and is arranged upstream of the printer nozzle 502 (i.e., before the filament material leaves the printer nozzle 502). The printer head 501 may (therefore) include a liquefier or heater. Reference numeral 201 indicates printable material. When deposited, this material is indicated as (3D) printing material, which is indicated by reference numeral 202.

[0096] Reference numeral 572 indicates a spool or roller containing material, particularly in the form of filament, which may be indicated as filament 320. The 3D printer 500 transforms this material into a layer 322 on a receiver article or deposited printing material in an extruder 321 downstream of the printer nozzle. Generally, the diameter of the extruder 321 downstream of the nozzle 502 decreases relative to the diameter of the filament 320 upstream of the printer head 501. Therefore, the printer nozzle is sometimes (also) indicated as an extruder nozzle. A 3D article 1 can be formed by arranging layers 322 and / or layers 322t on layers 322. Reference numeral 575 indicates a filament supply device, which here particularly includes a spool or roller and a drive wheel, indicated by reference numeral 576.

[0097] Reference number A indicates the longitudinal axis or the threaded shaft.

[0098] Reference numeral C schematically depicts a control system, such as a temperature control system specifically configured to control the temperature of the receiver article 550. The control system C may include a heater capable of heating the receiver article 550 to a temperature of at least 50°C, but particularly to a range up to about 350°C, such as at least 200°C.

[0099] Alternatively or additionally, in embodiments, the receiver plate may also be movable in one or both directions of the xy plane (horizontal plane). Furthermore, alternatively or additionally, in embodiments, the receiver plate may also be rotatable about the z-axis (vertical). Therefore, the control system can move the receiver plate in one or more of the x, y, and z directions.

[0100] Alternatively, the printer may have a head that can also rotate during printing. This type of printer has the advantage that the printing material cannot rotate during printing.

[0101] Layers are indicated by reference numeral 322 and have a layer height H and a layer width W.

[0102] Note that 3D printable material is not necessarily supplied to the printer head as filament 320. Furthermore, filament 320 can also be produced from 3D printable material within the 3D printer 500.

[0103] Reference numeral D indicates the diameter of the nozzle (the 3D printable material 201 is forced through this diameter).

[0104] Figure 1b schematically depicts the printing of the 3D article 1 being constructed in more detail in a 3D manner. Here, in this schematic diagram, the ends of the filaments 321 in a single plane are not connected to each other, but this may actually be the case in the embodiment. Reference numeral H indicates the height of the layer. Layers are indicated by reference numeral 322. Here, the layers have a substantially circular cross-section. However, they may generally be flat, such as having an external shape similar to a flat elliptical tube or flat elliptical cylinder (i.e., having a circular rod with a diameter compressed to a height smaller than the width, where the sides (defining the width) are (still) circular).

[0105] Therefore, Figures 1a-1b schematically depict some aspects of a fused deposition modeling 3D printer 500, including: (a) a first print head 501 including a printer nozzle 502, (b) a filament supply device 575 configured to supply the first print head 501 with a filament 321 comprising a 3D-printable material 201, and optionally (c) a receiver article 550. In Figures 1a-1b, the first or second printable material or the first or second printable material is indicated by the common indications of printable material 201 and printable material 202, respectively. Directly downstream of the nozzle 502, the filament 321 having the 3D-printable material becomes, upon deposition, a layer 322 having the 3D-printed material 202.

[0106] Figure 1c schematically depicts a stack of 3D printed layers 322, each layer having a layer height H and a layer width W. Note in the embodiment that the layer width and / or layer height may be different for two or more layers 322. Reference numeral 252 in Figure 1c indicates the object surface of the 3D article (schematically depicted in Figure 1c).

[0107] Referring to Figures 1a-1c, the deposited 3D-printable material filaments are directed to a layer having a height H (and width W). Layer 322 is deposited after layer 322 to generate 3D object 1.

[0108] For understanding, Figure 2a schematically depicts the particles and some aspects thereof. Note, in particular, that the particles used in this invention are relatively flat, see, for example, Figures 2d, 2e, and... Figure 5 .

[0109] The particles comprise material 411, or may be substantially composed of such material 411. Particle 410 has a first dimension or length L1. In the example on the left, L1 is essentially the diameter of the spherical particle. On the right, particles with non-spherical shapes, such as elongated particles 410, are depicted. Here, as an example, L1 is the particle length. L2 and L3 can be considered as width and height. Of course, particles can include combinations of particles with different shapes.

[0110] Figures 2b - 2f schematically depict some aspects of the particles 410. Some of the particles 410 have: a longest dimension A1 with a longest dimension length L1 and a shortest dimension A2 with a shortest dimension length L2. As can be seen from the figures, the longest dimension length L1 and the shortest dimension length L2 have a first aspect ratio greater than 1. Figure 2b schematically depicts the particle 410 in 3D, where the particle 410 has a length, height, and width, and where the particle (or flake) is substantially of an elongated shape. Thus, the particle can have an additional (short or major) axis, herein indicated as an additional dimension A3. In essence, the particle 410 is a fine particle, i.e., L2 < L1, particularly L2 << L1, and L2 << L3. L1 can be selected, for example, from the range of 5 - 200 μm; L3 can be as well. L2 can be selected, for example, from the range of 0.1 - 20 μm.

[0111] Figure 2c schematically depicts particles with a more irregular shape, such as pieces of broken glass, where a virtual minimum cuboid encloses the particles.

[0112] Note that the symbols L1, L2, L3 and A1, A2, A3 are only used to indicate the axes and their lengths, and the numbers are only used to distinguish the axes. Further note that: the particles are not substantially oval or cuboid. The particles can have any shape with at least the longest dimension substantially longer than the shortest dimension or the short axis, and it can be substantially flat. In particular, relatively regularly formed particles are used, i.e., the remaining volume of the fictional minimum cuboid enclosing the particles is small, such as less than 50% of the total volume, for example less than 25%.

[0113] Figure 2d schematically depicts in a cross - sectional view the particle 410 including a coating 412. The coating can include a light - reflecting material. For example, the coating can include (white) metal oxides. In other embodiments, the coating can consist essentially of a metal, such as an Ag coating. In other embodiments, the coating can be only on one or two large surfaces of the particle, rather than on the thin side surfaces of the particle.

[0114] Figure 2e schematically depicts particles of a relatively irregular shape. The particle material used can include, for example, small pieces of broken glass. Thus, the particle material embedded in a 3D - printable material or in a 3D - printed material can include a wide distribution of particle sizes. A cuboid can be used to define the (orthogonal) dimensions of length L1, L2, and L3.

[0115] Figure 2f schematically depicts cylindrical, spherical, and irregular - shaped particles, which generally are not used herein (see also above).

[0116] As shown in Figures 2b-2f, the term "first dimension" or "longest dimension" specifically refers to the length L1 of the smallest cuboid (cube) surrounding the irregularly shaped particle. When the particle is essentially spherical, the longest dimension L1, the shortest dimension L2, and the diameter are essentially the same.

[0117] Figure 3a schematically depicts a filament 321, which, when escaping from a printer nozzle (not shown), includes a 3D-printable material 201. The 3D-printable material includes a thermoplastic material 401 in which particles 410 are embedded.

[0118] Figure 3b schematically depicts 3D article 1, showing a rib-like structure (derived from deposited filaments) with height H. This height can also be indicated as width. Here, layer 322 of printed material 202 with height H and width W is schematically depicted. Figure 3b can be viewed as a stack of layers 322, with multiple adjacent stacks shown in Figure 1b.

[0119] Figure 4 An embodiment of a lamp or illuminator, indicated by reference numeral 2, is schematically depicted, comprising a light source 10 for generating light 11. The lamp may include a housing or lampshade or another element, which may include or may be a 3D-printed article 1. Here, a hemisphere (in a cross-sectional view) schematically indicates a housing or lampshade. The lamp or illuminator may be or may include an lighting device 1000 (which includes the light source 10). Thus, in a particular embodiment, the lighting device 1000 includes a 3D article 1. The 3D article 1 may be configured as one or more of the following: (i) at least a portion of the lighting device housing, (ii) at least a portion of the wall of the lighting chamber; and (iii) an optical element. Thus, in an embodiment, the 3D article may be reflective and / or transmissive to the light source 11. Here, the 3D article may be, for example, a housing or lampshade. The housing or lampshade includes an article portion 400. See also above for possible embodiments of the article portion 400.

[0120] Figure 5 Examples of flash sheets cut into hexagonal shapes are schematically depicted. They are cut from 12 and 25 μm thick (polyester) foils and metallized with an aluminum coating (e.g., in the range of about 10-60 nm). In the examples, their dimensions can range from about 50 μm to 3 mm (L1, see also Figure 2e or Figure 6e).

[0121] Figure 6a schematically depicts an embodiment of a 3D article 1 comprising 3D-printed material 202. Here, the 3D article 1 comprises multiple (e.g., three) layers 322 of 3D-printed material 202.

[0122] Here, for example, each layer of the 3D-printed material 202 includes a dopant material. The 3D-printed material 202 including the dopant material has the property that when the temperature of the 3D-printed material 202 including the dopant material increases above the temperature change T... c The optical properties irreversibly change from low-temperature optical properties to high-temperature optical properties. Here, at least the first portion 451 of one or more of the multiple layers 322 has low-temperature optical properties (when the temperature of the 3D-printed material 202, including the dopant material, rises above the change temperature T). c (When, it can irreversibly change to high-temperature optical properties), and at least the second portion 452 of one or more of the plurality of layers 322 has high-temperature optical properties. This is schematically depicted by bright dopant material particles in the first portion 451 and dark dopant material particles in the second portion 452. The latter particles are also indicated by reference numeral 410' to indicate that they can provide high-temperature optical properties.

[0123] For example, the 3D-printed material 202 may include one or more of the following: polyethylene (PE), low-density polyethylene (LDPE), polypropylene (PP), and low-density polypropylene (LDPP) or PP copolymers. For example, the 3D-printed material 202 may include a thermoplastic host material 401 for carrying dopant material 410, wherein the thermoplastic host material 401 of the first portion 451 and the second portion 452 is the same, wherein the printed material 202 includes dopant material 410 in a volume percentage range of 1-20 vol.%, wherein the volume percentage of dopant material 410 in the first portion 451 and the second portion 452 is the same, and wherein the wavelength-dependent transmittance and / or wavelength-dependent reflectance of the first portion 451 and the second portion 452 differ under vertical irradiation at wavelengths in the visible wavelength range.

[0124] Optical properties can be selected from a group consisting of reflectivity, transmittance, luminosity, absorptivity, and color.

[0125] Figure 6b schematically depicts an embodiment of 3D-printable material 201 escaping from nozzle 502, wherein different components may also be used. Thus, very schematically, Figure 6b also depicts at least a portion of a method for producing a 3D article 1 by fused deposition modeling, the method including a 3D printing stage comprising layer-by-layer deposition of an extrusion 321 comprising the 3D-printable material 201 to provide the 3D article Figure 1 comprising the 3D-printed material 202, wherein the 3D article 1 comprises layers 322 of the 3D-printed material 202, wherein the method further comprises controlling a first temperature T1 of the 3D-printable material 201 within a first temperature range, wherein the 3D-printable material 201 comprises a dopant material 410, and the 3D-printable material 201 comprising the dopant material 410 has a temperature that increases when the temperature of the 3D-printable material 201 comprising the dopant material 410 increases above a change temperature T. c Optical properties that irreversibly change from low-temperature optical properties to high-temperature optical properties, where the temperature of change T... c Within a first temperature range, wherein during at least a first portion of the 3D printing phase, the first temperature T1 is lower than the varying temperature T. c Furthermore, during at least the second part of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c .

[0126] For example, 3D printable material 201 includes one or more of polyethylene (PE), high-density polyethylene (HDPE), polypropylene (PP), and high-density polypropylene (HDPP), wherein the printable material 201 includes dopant material 410 in the range of 1-20 vol.%.

[0127] Figure 6c schematically depicts an embodiment of the method, which includes performing a 3D printing stage using a fused deposition modeling 3D printer 500, the 3D printer 500 including a printer head 501 having a printer nozzle 502, wherein the method includes controlling a first temperature T1 of 3D printable material 201 within the printer nozzle 502.

[0128] Reference numeral 504 indicates a heating element. Heating element 504 can be controlled by a control system C. Heating element 504 is specifically used to heat the 3D printable material 201 in the printer nozzle 502. Printable material 201 is schematically indicated. A filament 320 can be introduced into the printer head 501.

[0129] Figure 6d schematically depicts, for example, the temperature (left y-axis) in nozzle 502 over time. When the temperature is increased beyond the changing temperature, another optical property (value) can be obtained. This is schematically depicted with particles 410 and 410', and also schematically depicted with a parameter P (right y-axis) that also varies with temperature. The arrows on the left y-axis indicate the first temperature range.

[0130] Referring to FIG. 6e, in an embodiment, the dopant material 410 comprises polymer sheet-like particles with a metallic coating. Reference numeral 411 indicates a support material, such as a polymeric material, for example, a (biaxially oriented) PET film, and reference numeral 412 indicates a coating material, such as aluminum. Therefore, in an embodiment, the dopant material 410 comprising polyethylene terephthalate sheet-like particles with an aluminum coating can be applied. As schematically depicted, the metallic coating may be on only one side, but may also be conformal.

[0131] Referring, for example, to Figures 6a and 6e, the dopant material 410 may comprise polymer sheet particles with a metallic coating, particularly wherein the dopant material 410 comprises polyethylene terephthalate sheet particles with an aluminum coating, wherein the sheet particles have a particle length L1 and a particle height L2, wherein the aspect ratio of L1 / L2 is at least 5, wherein one or more layers 322 of the 3D-printed material 202 have a layer height H, wherein the layer height H is less than the particle length L1. In an alternative embodiment, the layer height H may be greater than the particle length L1.

[0132] Figure 6f schematically illustrates an embodiment in which a second portion can be formed (from the first portion) due to an increase in temperature. Here, one of the first portion 451 and the second portion 452 (the second portion in this case) has a more non-uniformly distributed dopant material 410 than the other of the first portion 451 and the second portion 452 (the first portion in this case). Therefore, as the temperature increases, the uniformity may increase, which may lead to changes in one or more optical properties. On the left, an aggregate of particles (or molecules) is schematically depicted, where the particles (or molecules) become more uniformly distributed as the temperature increases (from the top to the bottom). On the right, (dopant) particles comprising dopant material are depicted, from which particles can be released when the temperature increases above the change temperature, thereby achieving a more uniform distribution. It is also possible that the released particles (or molecules) can react with other particles or molecules, thereby changing the optical properties.

[0133] Therefore, a method is also depicted very schematically (particularly on the left), wherein the 3D printable material comprises a non-uniformly distributed dopant material 410, and wherein the uniformity of the dopant material 410 increases, for example, attributable to an increase in the mobility of the dopant material 410, when the temperature of the 3D printable material 201 comprising the dopant material 410 is increased above a varying temperature Tc.

[0134] In the embodiments, the dopant material 410 includes one or more of quantum dots embedded in polymer particles and luminescent molecules.

[0135] Glitter sheets are a class of materials that can give luminaires an attractive appearance. Glitter sheets can be produced by cutting PET films with a thin aluminum layer into flat granules of precise size and shape. The film can also have a microstructure, giving the glitter sheet an even more attractive appearance. We have tried producing polymer filaments with glitter sheets, such as polycarbonate, at processing temperatures above 200°C. However, it has been observed that at such elevated temperatures, the glitter sheets lose their attractive reflective appearance. When we use polymers that can be processed below 200°C (e.g., polypropylene), we can produce filaments with glitter sheets for FDM printing. These filaments are then used in FDM to produce objects with glitter sheets.

[0136] Here, in the embodiments, among other things, it is recommended to use a shear rate of 1s at 180°C. -1 Polymers with a viscosity <5000 Pa·s (when the melting temperature of the crystalline polymer is below 200°C). We have found that polyolefins such as polypropylene and polyethylene are particularly suitable materials for producing FDM filaments with glitter flakes.

[0137] To produce glitter flakes in a polymer, we use polypropylene and add glitter flakes of various sizes to the polymer. After extruding the material at 190°C, filaments for FDM printing are produced. The glitter flakes are 12 micrometers thick, hexagonal in the transverse direction, and have dimensions of 50x50, 100x100, 200x200, and 400x400 micrometers. Using these flakes, we printed various shapes. When the layer height for FDM printing was selected to be lower than the transverse dimensions of the glitter flakes, it was found that the glitter flakes were primarily oriented in the printing plane, exhibiting a highly reflective decorative appearance. We also used the filaments to print cylinders. During printing, the temperature in the nozzle was also varied, and printing was performed at 240°C and 190°C. In areas printed at 190°C, the glitter flakes remained intact and had a reflective appearance. In other areas printed at 240°C, the glitter flakes were damaged during printing, and the shiny appearance disappeared. Therefore, by changing the temperature during printing, the appearance of the printed object can be altered, and patterns can be introduced locally.

[0138] Those skilled in the art will understand that the term "substantially" as used herein, such as "substantially comprises," can also include embodiments having connotations such as "completely," "entirely," "all," etc. Therefore, the adjective "substantially" may be removed in embodiments. Where applicable, the term "substantially" can also refer to 90% or higher, such as 95% or higher, particularly 99% or higher, even more particularly 99.5% or higher, including 100%. The term "comprising" also includes embodiments in which the term "comprising" means "consisting of." The term "and / or" specifically refers to one or more items mentioned before and after "and / or." For example, the phrase "item 1 and / or item 2" and similar phrases can refer to one or more of item 1 and item 2. The term "comprising" in one embodiment may mean "consisting of," but in another embodiment may also mean "containing at least the defined species and optionally one or more other species."

[0139] Furthermore, the terms first, second, third, etc., in the specification and claims are used to distinguish similar elements and are not necessarily used to describe an order or chronological sequence. It should be understood that such terms are interchangeable where appropriate, and the embodiments of the invention described herein can operate in orders other than those described or illustrated herein.

[0140] The apparatus described herein is based on its operation. Those skilled in the art will understand that the invention is not limited to the method of operation or the apparatus in operation.

[0141] It should be noted that the embodiments mentioned above are illustrative rather than limiting of the invention, and those skilled in the art will be able to devise many alternative embodiments without departing from the scope of the appended claims. Any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The use of the verb "comprising" and its variations does not exclude the presence of elements or steps other than those stated in the claims. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In device claims enumerating several components, several of these components can be embodied by the same hardware article. The fact that certain measures are enumerated in dissimilar dependent claims does not indicate that combinations of these measures cannot be used for profit.

[0142] The present invention also provides a control system that can control an apparatus or device or system, or can perform the methods or processes described herein. Furthermore, the present invention provides a computer program product that, when functionally coupled to or included in a computer within an apparatus or device or system, controls one or more controllable elements of such apparatus or device or system.

[0143] The invention is also applicable to devices including one or more characterizing features described in the specification and / or shown in the drawings. The invention also relates to a method or process including one or more features described in the specification and / or shown in the drawings.

[0144] The various aspects discussed in this patent can be combined to provide additional advantages. Furthermore, those skilled in the art will understand that embodiments can be combined, and more than two embodiments can be combined. Additionally, certain features can form the basis of one or more divisional applications.

[0145] It goes without saying that one or more of the first (printable or printable) material and the second (printable or printable) material may contain fillers such as glass and fibers, which affect the T of the (multiple) materials. g or T m No impact.

[0146] As indicated above, glitter flakes can typically be flat granules of PET, for example, with a relatively thin aluminum coating. Printable thermoplastic polymer filaments incorporating glitter flakes as additives have been produced and used. 3D printing of such filaments is performed at high temperatures, the exact processing temperature depending on the thermoplastic polymer. For polycarbonate, processing temperatures exceed 200°C, and the inventors observed that at these high temperatures, the glitter flakes may lose their attractive reflective appearance. This has not been observed with polymers that can be processed below 200°C. Suitable polymers are, for example, polyolefins such as polypropylene and polyethylene. When the temperature rises above 200°C during printing, the reflective appearance of the glitter flakes can be “turned off.”

Claims

1. A method for producing a 3D article (1) by fused deposition modeling, the method comprising a 3D printing stage, the 3D printing stage comprising layer-by-layer deposition of an extrusion (321) comprising a 3D-printable material (201) to provide the 3D article (1) comprising layers (322) of the 3D-printed material (202), wherein the 3D article (1) comprises layers (322) of the 3D-printed material (202). The method further includes controlling a first temperature T1 of the 3D printable material (201) within a first temperature range. The 3D printable material (201) mentioned above includes: -Thermoplastic base material (401), and - A dopant material (410) in the range of 1 vol.% to 20 vol.%, said dopant material (410) comprising polymer sheet-like particles with a metallic coating, The 3D printable material (201) described therein has the following optical properties: when the temperature of the 3D printable material (201) increases above the temperature change T... c At that time, the optical properties irreversibly change from low-temperature optical properties to high-temperature optical properties, and the optical properties are selected from the group consisting of reflectivity, transmittance, luminosity, absorptivity, and color. The temperature T that is changing c Within the first temperature range, wherein during at least a first portion of the 3D printing phase, the first temperature T1 is lower than the changing temperature T. c ,and During at least the second portion of the 3D printing phase, the first temperature T1 is higher than the changing temperature T. c .

2. The method of claim 1, wherein the method includes performing the 3D printing stage using a fused deposition modeling 3D printer (500), the fused deposition modeling 3D printer (500) including a printer head (501) including a printer nozzle (502), wherein the method includes controlling a first temperature T1 of the 3D printable material (201) within the printer nozzle (502).

3. The method according to any one of the preceding claims, wherein the thermoplastic host material (401) comprises one or more of the following: polyethylene (PE), low-density polyethylene (LDPE), polypropylene (PP) and low-density polypropylene (LDPP), or copolymers of two or more of these.

4. The method according to claim 1 or 2, wherein the dopant material (410) comprises polyethylene terephthalate flake particles with an aluminum coating.

5. The method according to claim 3, wherein the dopant material (410) comprises polyethylene terephthalate flake particles having an aluminum coating.

6. The method according to claim 1 or 2, wherein the dopant material (410) comprises sheet-like particles having a particle length (L1) and a particle height (L2), the aspect ratio L1 / L2 of the particle length (L1) and particle height (L2) being at least 5, and wherein the method comprises printing one or more layers (322) of the 3D-printed material (202) having a layer height (H), wherein the layer height (H) is less than the particle length (L1), and wherein the layers are stacked.

7. The method according to claim 1 or 2, wherein the dopant material (410) comprises one or more of the following: quantum particles, organic light-emitting molecules, and light-emitting quenching molecules.

8. A 3D article (1) comprising a 3D-printed material (202), wherein the 3D article (1) comprises a plurality of layers (322) of the 3D-printed material (202), wherein the 3D-printed material (202) comprises: -Thermoplastic base material (401), and - A dopant material (410) in the range of 1 vol.% to 20 vol.%, said dopant material (410) comprising polymer sheet-like particles with a metallic coating, The 3D-printed material (202) including the dopant material (410) has the following optical properties: when the temperature of the 3D-printed material (202) including the dopant material (410) increases above the temperature change T... c At that time, the optical properties irreversibly change from low-temperature optical properties to high-temperature optical properties, and the optical properties are selected from the group consisting of reflectivity, transmittance, luminosity, absorptivity, and color. At least a first portion (451) of one or more of the plurality of layers (322) has the low-temperature optical properties, and at least a second portion (452) of one or more of the plurality of layers (322) has the high-temperature optical properties.

9. The 3D article (1) according to claim 8, wherein the thermoplastic host material (401) comprises one or more of the following: polyethylene (PE), low-density polyethylene (LDPE), polypropylene (PP) and low-density polypropylene (HDPP).

10. The 3D article (1) according to any one of claims 8 to 9, wherein the dopant material (410) comprises polyethylene terephthalate flake particles with an aluminum coating, wherein the flake particles have a particle length (L1) and a particle height (L2), the aspect ratio L1 / L2 of the particle length (L1) and the particle height (L2) is at least 5, wherein one or more layers (322) of the 3D printed material (202) have a layer height (H), wherein the layer height (H) is less than the particle length (L1), and wherein the layers are stacked.

11. The 3D article (1) according to any one of claims 8 to 9, wherein the thermoplastic body material (401) of the first portion (451) and the second portion (452) is the same, wherein the volume percentage of the dopant material (410) in the first portion (451) and the second portion (452) is the same, and wherein the wavelength-dependent transmittance and / or wavelength-dependent reflectance of the first portion (451) and the second portion (452) are different under vertical irradiation at wavelengths in the visible wavelength range.

12. The 3D article (1) according to claim 10, wherein the thermoplastic body material (401) of the first portion (451) and the second portion (452) is the same, wherein the volume percentage of the dopant material (410) in the first portion (451) and the second portion (452) is the same, and wherein the wavelength-dependent transmittance and / or wavelength-dependent reflectance of the first portion (451) and the second portion (452) are different under vertical irradiation at wavelengths in the visible wavelength range.

13. The 3D article (1) according to claim 11, wherein a portion of the first portion (451) and the second portion (452) has a distribution of the dopant material (410) with a lower uniformity than the other portion of the first portion (451) and the second portion (452).

14. A lighting device (1000) comprising a 3D article (1) according to any one of claims 8 to 13, wherein the 3D article (1) is configured as one or more of: (i) at least a portion of a lighting device housing, (ii) at least a portion of a wall of a lighting chamber, and (iii) an optical element.

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