Method for manufacturing a deformable article

Abstract

A method for producing a deformable article includes extruding a plurality of thermoplastic elastomer molten beads in parallel and layer-by-layer in accordance with machine-readable instructions from a plurality of co-moving extrusion nozzles to form an article having a density of 60 g / l or greater but less than 120 g / l and a compressive strength at 40% compression according to DIN EN ISO 3386-1:2015-10 of 1 kPa or greater but 9 kPa or less.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a deformable article, comprising extruding a plurality of thermoplastic elastomer molten beads in parallel and layer-by-layer in accordance with machine-readable instructions from a plurality of co-moving extrusion nozzles to form an article having a density of 60 g / l or greater but less than 120 g / l and a compressive strength at 40% compression according to DIN EN ISO 3386-1:2015-10 of 1 kPa or greater but 9 kPa or less. [Background technology]

[0002] Existing technology for thermoplastic cushioning materials is primarily based on polyester woven technology designed to produce internal high-stiffness polyester springs (see also "3D fabric", https: / / www.pressless.de / en / what-is-a-3d-fabric / , https: / / www.ikea.com / nl / en / p / himlavalv-3d-mattress-for-cot-90321006 / ). Polyester products cannot be locally customized.

[0003] Other known processes for producing thermoplastic cushioning materials are based on additive manufacturing, for example by thermoplastic powder or thermoplastic filament printing.

[0004] German Patent No. 102015100816 discloses a process for manufacturing a body support element formed by a mattress, cushion, seat or seat part, which process comprises the process steps of defining printing data for forming a person-specific three-dimensional support structure and manufacturing the body support element using the printing data by a 3D printer. Using the printing data, it is possible to generate areas of different elasticity by forming cavities of different sizes and / or different numbers by the 3D printer.

[0005] U.S. Patent Application Publication No. 2020 / 325951 relates to a deformable body constructed from multiple layers of polymeric build material, with a build direction perpendicular to the layers. The body preferably comprises layers formed from the build material and having multiple pairs of curves extending in the same direction, each pair comprising two periodic curves extending in opposite directions, the pairs of curves having a maximum distance and a minimum distance relative to each other. In some layers, at least one of the maximum distances of one curve in an adjacent pair of curves is connected to a maximum distance of the adjacent curve, in a further portion of the layer, at least one of the maximum distances of one curve in an adjacent pair of curves is not connected to a maximum distance of the adjacent curve, in a further portion of the layer, at least some of the minimum distances of the adjacent pair of curves are connected to each other, and in a further portion of the layer, at least some of the minimum distances of the adjacent pair of curves are not connected to each other. This publication also relates to a method for manufacturing the body, as well as an apparatus for supporting and / or supporting a person, including a body according to the present invention. The body can be used as, inter alia, a mattress or a vehicle seat.

[0006] Regarding the generation of instructions for extruders, the publication, "FullControl GCode Designer: Open-source software for unconstrained design in additive manufacturing," by Andrew Gleadall, Additive Manufacturing, Volume 46, 2021, 102109, ISSN 2214-8604, https: / / doi.org / 10.1016 / j.addma.2021.102109 (https: / / www.sciencedirect.com / science / article / pii / S2214860421002748), discusses a design approach in which the user specifies every segment of the print path along with all printing parameters that may relate to geometric and non-geometric factors at every point along the print path. The machine control code (G-code) is generated directly by the software. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Patent No. 102015100816 [Patent Document 2] US Patent Application Publication No. 2020 / 325951 [Non-patent literature]

[0008] [Non-Patent Document 1] "FullControl GCode Designer:Open-source software for unconstrained design in additive manufacturing" by Andrew Gleadall,Additive Manufacturing,Volume 46,2021,102109,ISSN 2214-8604 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to overcome the limitations of existing production technology and provide a route to the efficient manufacture of soft cushioning bodies with controlled dimensions and local material structure. [Means for solving the problem]

[0010] This object is achieved by a method according to claim 1 and a deformable article according to claim 13. Advantageous embodiments are the subject matter of the dependent claims, which may be freely combined unless the context clearly indicates otherwise.

[0011] Accordingly, a method for manufacturing a deformable article is provided, the method comprising extruding a plurality of thermoplastic elastomer molten beads in parallel and layer-by-layer in accordance with machine-readable instructions from a plurality of co-moving extrusion nozzles.

[0012] The number of layers may be, for example, 100 or more and 600 or less, preferably 150 or more and 500 or less, and more preferably 200 or more and 400 or less.

[0013] The thermoplastic elastomer (TPE) may be a block copolymer of hard and soft blocks. Examples of suitable materials include thermosetting polyurethane elastomers (PUR), thermoplastic copolyamides (TPA), thermoplastic copolyesters (TPC), olefin-based thermoplastic elastomers (TPO), styrene block copolymers (TPS), urethane-based thermoplastic elastomers (TPU), olefin-based crosslinked thermoplastic elastomers (TPV), polyvinyl chloride-based thermoplastic elastomers (PVC), silicone-based thermoplastic elastomers, and combinations of at least two of these elastomers. Combinations of three or more, four or more, or five or more of these thermoplastic elastomers are also possible. The TPE material may also include a thermoplastic vulcanizate or a vulcanizable rubber that can be extruded through a nozzle before subsequent vulcanization.

[0014] For the purposes of the present invention, a polymer is elastic if its elongation at break in a tensile test according to DIN 53504 is 50% or more and provides the required body compression set after 15% compression (DIN ISO 815-1, 72 hours, 23°C), which may then be 50% or less, preferably 30% or less, particularly preferably 25% or less.

[0015] The TPE may also contain further additives such as fillers, stabilizers, and further polymers. The total content of additives in the elastic polymer may be, for example, from 0.1 to 70% by weight, preferably from 1 to 40% by weight.

[0016] The melt volume rate (MVR) of suitable TPEs according to ISO 1133 (20°C above the melting point, 5 kg, 10 min) is 20 to 90 (preferably 30 to 80, more preferably 35 to 65) cm 3 / 10 minutes may be fine.

[0017] TPEs, especially TPUs, can exhibit a rapid melt viscosity drop with temperature. The melting properties are determined by the change in MVR (Melt Volume Rate) as a function of temperature according to ISO 1133 with a preheat time of 5 minutes and a load of 10 kg. The melting properties are determined by the change in MVR at the onset temperature T x 5 to 15 cm 3 / 10 min starting value, T x+20 As a result of a temperature increase of 20°C to 20cm³ / 10 min or more, preferably 30cm 3 / An increase of more than 10 minutes is considered "sudden."

[0018] The TPE may have a melting point, defined as the crossover point between the storage modulus G' and the loss modulus G" by dynamic mechanical analysis (DMA) at 1 Hz torsion, 1% strain, and a heating rate of 2°C / min, between 80°C and 260°C, preferably between 100°C and 240°C, more preferably between 140°C and 200°C, and most preferably below 180°C.

[0019] The TPE may have a glass transition temperature (according to DMA, DIN EN ISO 6721) above 80°C or between -80°C and 10°C, preferably between -70°C and 0°C, more preferably between -60°C and -10°C.

[0020] Machine-readable instructions are the output of software that generates machine-readable instructions, and the input for generating the instructions does not include a representation of a three-dimensional computer-aided design (3D-CAD) model of the article to be manufactured, nor software-generated sliced ​​layers of the 3D-CAD model of the article to be manufactured. In particular, polygonal representations such as those found in STL files are excluded. Thus, a workflow in which an article is designed using CAD software such as Autodesk or AutoCAD, followed by export to slicer software and subsequent generation of machine-readable instructions is excluded.

[0021] The extrusion nozzle moves at a certain nozzle speed, the extruded molten bead has a certain diameter, and the product of the nozzle speed and the diameter of the extruded bead is 25 mm. 2 / s or more 80mm 2 / s or less. 28mm 2 / s or more 75mm 2 / s or less is preferred.

[0022] It is recognized that the diameter of the extruded bead may be larger than the inner diameter of the nozzle through which it is extruded. The diameter of the extruded bead is determined by the equation for an ideal cylinder (V=(d / 2) 2 *π*h), where d is the bead diameter, V is the volume of the cylinder, and h is the extrusion path length in G-code. The volume V can be calculated from the weight of the extruded beads and the density of the extruded material. The preferred diameter of the extruded beads is 0.35 mm to 0.65 mm, more preferably 0.40 mm to 0.62 mm.

[0023] The thermoplastic elastomer has a Shore A hardness according to DIN ISO 7619 of 45 to 94. A Shore A hardness of 60 to 92 or 70 to 86 is preferred.

[0024] The extruded molten beads form a layer in the article having a height of from 0.30 mm to 0.55 mm, preferably from 0.35 mm to 0.55 mm.

[0025] The diameter of the extruded beads is 100% to 145% of the height of the layer formed by the beads, preferably 110% to 145%, and more preferably 120% to 140%.

[0026] Each extrusion nozzle has an inner diameter of 0.3 mm to 0.7 mm. Individual nozzles may have different inner diameters within the ranges described. The difference in diameter may be 0.05 mm or more, preferably 0.1 mm to 0.4 mm.

[0027] Adjacent extruded beads in a layer have an average distance from each other of 6 mm to 20 mm, preferably 6 mm to 13 mm. It is also preferred that the distance between adjacent extruded beads in a layer is constant.

[0028] On average, each layer of the article contacts its preceding layer by no more than 60% of its associated extruded bead diameter. This layer overlap can be determined graphically by extracting the extrusion path vector file.

[0029] The article includes a wall formed by extruding a thermoplastic elastomer and a void, thereby establishing a density of the article and a compressive strength according to DIN EN ISO 3386-1:2015-10 at 40% compression.

[0030] This results in an article having a density of 60 g / l to less than 120 g / l (preferably 60 g / l to 110 g / l) and a compressive strength according to DIN EN ISO 3386-1:2015-10 at 40% compression of 1 kPa to 9 kPa (preferably 1.5 kPa to 8 kPa, more preferably 2 kPa to 6 kPa). Preferably, a fourth compression cycle is used to determine the compressive strength.

[0031] It was surprising that the method of the present invention was successful in forming articles with the above-mentioned densities and compressive strengths. The reason for this unexpected success lies in the fact that standard FFF (Fused Filament Fabrication) 3D printing flags layer heights approaching 2 / 3 of the nozzle diameter in the slicer program, resulting in an unsatisfactory product due to poor layer adhesion and poor product resolution.

[0032] Surprisingly, it has also been found that the quality of the buffer product (deformable article) and the production efficiency of the buffer product are particularly good when the product of nozzle speed and extruded bead diameter is within the above-mentioned range.

[0033] In producing a deformable article having the claimed overall density and compressive strength, steps not corresponding to the method according to the invention may be performed, as long as steps corresponding to the method are performed. This may be the case when denser or larger, heavier sides of the article are produced. Preferably, 80% or more or 90% or more of the volume of the deformable article is produced by the method according to the invention.

[0034] The diameter of the extruded bead can be between 70% and 150% of the inner diameter of the nozzle through which it is extruded.

[0035] The resulting volumetric build rate of deformable articles per nozzle is 0.4 l / h or more, preferably 0.6 l / h or more, more preferably 0.8 l / h or more, most preferably 1 l / h or more, but may be 2 l / h or less.

[0036] At least two nozzles may be arranged parallel to each other and at an angle of 80° to 100° (preferably 85° to 95°) relative to the direction of nozzle travel. At least four nozzles may be stacked in at least two rows, with at least two nozzles arranged parallel to each other and at an angle of 80° to 100° (preferably 85° to 95°) relative to the direction of nozzle travel.

[0037] The molten bead of TPE is extruded simultaneously through at least two nozzles having different volumetric throughputs, and the volumetric throughput can differ by 10% to 300%, preferably 20% to 250%, and more preferably 30% to 200%, by volume between the lower and higher volumetric throughput nozzles. Preferably, the difference in volumetric throughput is achieved with nozzles of the same nozzle diameter.

[0038] The volumetric output of the at least two nozzles can vary by 20% to 250% by volume, more preferably 30% to 200% by volume, over the build time of the deformable article. Preferably, the change in volumetric output can occur within 20 or fewer build layers, preferably 10 or fewer build layers, more preferably 3 or fewer build layers.

[0039] By switching from an extrusion mode to a transfer mode, the volumetric output of the at least two nozzles can be changed at least once on at least one build layer of the structure.

[0040] The gravimetric throughput of at least one nozzle used in the extrusion process can differ from at least one other nozzle by 10% or more of the build time, in terms of throughput measured in g / h, preferably by at least 15% by weight, more preferably by at least 20% by weight, and most preferably by at least 50% by weight, or by at least 10 minutes of cumulative build time.

[0041] At least two nozzles may be arranged on a beam that can be moved in the build direction, with the longer direction of the beam being perpendicular to the build direction. The beam is preferably fixed so that its position can be changed by 60 to 150 degrees, allowing for changes in the build direction during the build process, preferably when moving to the next build layer.

[0042] The at least two nozzles may be arranged so that they can move parallel to X and Y, and may also be movable in Z. It is also possible that the spatial movement of the nozzles in at least one direction is smaller than the movement in at least one other direction by a factor of 2 or more, preferably by a factor of 4 or more, and most preferably by a factor of 8 or more.

[0043] At least two nozzles can be arranged so that they can move simultaneously parallel and perpendicular to the build direction. They can also be mounted in any known given XYZ, Delta, or CoreXY or CoreXZ design.

[0044] The at least two nozzles may be positioned such that the build table can be moved in the XY directions under the nozzle mechanism, and may also be moved in the Z direction. The build table may be free to move in the XY directions, and the nozzles may be free to move in the Z direction. The spatial movement of the build table in at least one direction may be smaller than the movement in at least one other direction by a factor of at least 2, preferably at least 4.

[0045] The build table may be capable of being heated or cooled. The method may also be carried out in an enclosed space for safety and / or heat control reasons.

[0046] The nozzles can also be positioned parallel to the mounting position, which allows them to move in the build direction, with the longer direction of the beam perpendicular to the build direction. The build platform is preferably freely rotatable, and its orientation can be changed by 60° to 150°, and is positioned to allow for changes in the build direction during the build process, preferably when moving to the next layer.

[0047] It is also possible to vary the material, build density and / or build shape during the course of manufacturing the article in the method of the present invention. This can be done in the xy plane and along the z axis. The article resulting from the method of the present invention can be white or transparent.

[0048] The number of beads applied to the width of the main body's building area in one building layer can be, on average, 2 (line spacing 5 mm) to 0.75 (line spacing 15 mm) beads / cm building width, preferably 1.7 to 0.8, and more preferably 1.5 to 0.9.

[0049] At least the spacing distance from one nozzle to another can be less than the median spacing of the nozzles across the width of the build by a factor of 0.9 or less, preferably 0.8 or less, more preferably 0.7 or less.

[0050] It is also possible for the output of at least one nozzle to be different from the average output of the nozzles across the width or length of the build. Preferably, at least the first and last of the parallel nozzles have an output that is 10% to 100% higher than the average output of all nozzles.

[0051] The nozzle temperature can be 30°C to 110°C higher than the melting point of the TPE (defined as the intersection of the storage modulus G' and loss modulus G" measured by DMA at 1 Hz torsion, 1% strain, and a heating rate of 2°C / min), preferably 40°C to 100°C, and most preferably 40°C to 90°C higher than the melting point of the TPE.

[0052] The temperature of the build table in this method can be preferably between 5° C. and 100° C., preferably between 10° C. and 60° C., and most preferably between 15° C. and 30° C. In the most preferred embodiment, the temperature of the build table and the temperature within the potential build enclosure are within ±10° C. of the ambient temperature.

[0053] It is possible for the average material temperature of the build over the build time to be ±10°C above the ambient temperature. Preferably, the build temperature is ±5°C above the ambient temperature.

[0054] The extruded TPE beads can also be applied in parallel by a parallel array of nozzles fed by melted TPE pellets in front of the nozzles.

[0055] Melting can be conveniently carried out by compression molding in a commercially available extruder, with a heated piston or with a heated nozzle plate, or by extrusion through a parallel melt spin pump.

[0056] The applied parallel molten beads can be provided at least every 50 layers or less, preferably at least every 30 layers or less, more preferably at least every 20 layers or less, and most preferably at least every 3 layers that can be superimposed on another previous layer.

[0057] The multiple bead extruders can apply beads to the previous layer on average at least every 50 layers or less, preferably at least every 30 layers or less, more preferably at least every 20 layers or less, and most preferably at least every 3 layers or less, at a fixed angle of 160° or less and 20° or more.

[0058] The shaft on which the multiple bead extruders are mounted may have a directional capability to move in at least one, preferably two, directions (e.g., y and z) that is limited in distance to no more than 30%, preferably no more than 15%, and more preferably no more than 10% of its capability to move in at least one other direction (e.g., x), preferably two other directions (e.g., x and z).

[0059] Each extrusion nozzle can be individually controlled to extrude at a desired amount in the range of 0% to 300% (0 to 250, 0 to 200, 0 to 150, 0 to 100) of the median extrusion rate across all nozzles in the multiple extrusion apparatus.

[0060] It is possible for more than 50%, preferably more than 85%, and most preferably more than 90% of the extrusion nozzles to have the same diameter. It is also possible for up to 50%, preferably up to 15%, and most preferably up to 10% of the nozzles to have a larger or smaller diameter, with a diameter difference of up to -50% and +100%.

[0061] Multiple bead extruder nozzles can be fixed perpendicular to the shorter dimension Y of the build zone. It is also possible for one extruder to feed multiple nozzles, preferably 2 to 8, more preferably 4 to 6.

[0062] It is possible that the TPE material may vary among layers, or at least different or colored TPE materials may be used in at least one layer of the build.

[0063] It is possible to use multiple materials in one object.

[0064] It is possible to extrude multiple materials through one nozzle during a build.

[0065] During the build, multiple materials can be extruded through different nozzles.

[0066] It is possible that the materials may have different colors to allow for easy separation of the materials for material recycling.

[0067] It is possible that the same material can have different colors to allow for optical marking of different buffer areas.

[0068] On average, at least 50% of the nozzles are capable of extruding molten TPE beads in parallel.

[0069] The volume dispensed through the at least one nozzle can vary over the time of the build.

[0070] Different thermoplastic materials are used for different layers, and the different layers can be easily separated horizontally in the XY axis for recycling, resulting in a pure, single-quality material.

[0071] In preferred embodiments, non-TPE materials and endless fiber, long fiber, or short fiber reinforced materials may also be used as part of the shaped article.

[0072] The process can be controlled to provide a layer repetition period of less than 300 seconds, preferably less than 200 seconds, and most preferably less than 100 seconds.

[0073] The molten beads can be extruded onto a movable "continuous" printing platform, for example in the form of a conveyor belt, to allow continuous printing. The molten beads can also be extruded onto a rotating platform that can rotate at least 90° or can rotate freely.

[0074] The build area is 0.5m 2 More than 1m, preferably 1m 2 At least 1.5m, preferably 1.5m 2 The build area can also be rectangular with two sides having a ratio of 1:1 or more and 3:1 or less. [Brief explanation of the drawings]

[0075] [Figure 1] Indicates the rectangular pattern "Rect." [Figure 2] Shows gyroid pattern "Gyr." [Figure 3] Shows the triangular pattern "Triang." [Figure 4] Shows the honeycomb pattern "Honeyc." [Figure 5] Shows the "Wiggle" pattern. [Figure 6] Shows the "Grid" pattern. DETAILED DESCRIPTION OF THE INVENTION

[0076] According to one embodiment, inputs to the software that generates the machine-readable instructions include user-defined segments of the path of travel of the extrusion nozzle, the definition including spatial coordinates and extrusion instructions. Suitable software for this purpose is "FullControl GCode Designer," mentioned in the introduction of this disclosure.

[0077] According to another embodiment, the output of the software that generates the machine-readable instructions includes G-code.

[0078] According to another embodiment, the thermoplastic elastomer is a thermoplastic polyurethane (TPU). Preferably, the elastomer is a thermoplastic polyurethane elastomer obtained from the reaction of at least the following components: a) at least one organic diisocyanate, b) at least one compound having isocyanate-reactive groups and a number-average molar mass (Mn) of ≧800 g / mol to ≦4000 g / mol and an overall number-average functionality of ≧1.8 to ≦2.5, and c) at least one chain extender having a molecular weight of 60-450 g / mol and an overall number-average functionality of 1.8 to 2.5.

[0079] Preference is given to a) hexamethylene 1,6-diisocyanate, cyclohexane 1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate isomer mixtures with a weight content of more than 96% diphenylmethane 4,4'-diisocyanate, in particular diphenylmethane 4,4'-diisocyanate and naphthylene 1,5-diisocyanate. These diisocyanates can be used individually or mixed with one another.

[0080] Preferred for b) are, for example, polyether diols which can be produced from ethylene oxide and / or propylene oxide and / or tetrahydrofuran and which have a molecular weight distribution Mw / Mn of less than or equal to 3, preferably less than or equal to 2, most preferably less than or equal to 1.5, as measured by universal GPC. The number-average molar mass Mn of the polyether diols is preferably between 800 and 6000 g / mol, more preferably between 900 and 4000, most preferably between 1000 and 3000. These compounds can be used individually or mixed with one another.

[0081] Preferred for c) are ethanediol, butane-1,4-diol, hexane-1,6-diol, 1,4-di(β-hydroxyethyl)hydroquinone and 1,4-di(β-hydroxyethyl)bisphenol A. Mixtures of the above chain extenders can also be used.

[0082] In preferred TPUs, the mass fraction of polyethers with a molecular weight of ≧900 g / mol and ≦4000 g / mol is ≧60%, more preferably ≧70%, most preferably ≧80%, relative to the total polyether content.

[0083] The thermoplastic polyurethane preferably contains C3 ether units such as polypropylene glycol units. For example, the mass fraction of polypropylene oxide-based polyethers having a molecular weight of 900 g / mol to 4000 g / mol may be 60% or more, preferably 70% or more, and most preferably 80% or more, based on the total polyether content.

[0084] An example of such a material is a TPU having a composition comprising more than 80% by weight of polypropylene glycol, MDI, butanediol, and hexanediol. The polypropylene glycol used in the TPU may have a number average molecular weight Mn between 800 and 4000 g / mol and a polydispersity Mw / Mn of 1.5 or less.

[0085] According to another embodiment, the cross section of the article comprises repeating units of straight segments at an angle to each other, repeating units of curved segments, repeating units of curved segments at an angle to each other, or a combination of two or more of the foregoing repeating units.

[0086] According to another embodiment, a first cross-section of the article is different from a second cross-section parallel to the first cross-section.

[0087] According to another embodiment, the first cross-section of the article corresponds to the second cross-section of the rotated article.

[0088] The TPE material can be extruded so that between one layer and the next, the molten bead applied to the second layer contacts, on average, no more than 60%, preferably no more than 50%, more preferably no more than 40%, and most preferably no more than 20% of the calculated applied bead width of the material of the previously applied layer.

[0089] The TPE material can preferably be extruded in one layer and in at least one successive layer throughout the entire build such that the applied molten beads are stacked horizontally against one another at angles of 20° or more, preferably 40° or more, most preferably 60° or more and 160° or less, preferably 140° or less, and most preferably 120° or less, and only contact at points, bridging a point-to-point distance that is at least 8 times, preferably 10 times, and most preferably 12 times the contact length of the contact points of the two beads. Preferably, these successive layers are repeated more than 5 times in the build, more preferably more than 10 times, and most preferably more than 30 times.

[0090] Surprisingly, even with this low surface connection area and volume density of the shaped object, the method and material combination of the present invention makes it possible to produce a cushioning material with sufficient strength in the XY and Z directions to withstand 1000 repeated compression cycles of 40% of the height according to DIN EN ISO 3386-1:2010-09, with a compression strength of 9 kPa or less and a compression set of 30% or less, preferably 20% or less, most preferably 10% or less.

[0091] The molten TPE beads extruded in one layer are allowed to trace a curve parallel to the build direction for at least 20%, preferably at least 30%, at least 50%, and most preferably at least 80% of the length to avoid time-consuming and difficult direction changes.

[0092] The shaping concept can include a linear movement of the nozzle from start to finish in the x or y direction in one layer and a zigzag movement of the nozzle in the x and y directions in at least one layer out of three, preferably one layer out of two, with the nozzle performing repeated lateral movements at an angle between the movement directions that is greater than the distance between two parallel spaced nozzles, preferably greater than 1.5 times the distance between two parallel spaced nozzles, greater than 20° and less than 120°.

[0093] The nozzles may operate in an orthogonal system with most nozzles mounted parallel on beams arranged perpendicular to the long dimension of the build platform, the longest dimension of the build being designated X, and Y, perpendicular to the horizontal direction of X, being less than or equal to X, and preferably the smallest dimension of the build being perpendicular to X, which is designated Z.

[0094] The molten TPE beads extruded from the multiple bead extruders can be applied in parallel lines perpendicular to the smaller dimension (X or Y direction) of the cushion body by 10% or more, preferably 20% or more, most preferably 30% or more of the absolute extrusion length of the beads passing through one nozzle during the build time, and in lines parallel to the larger build dimension (X or Y direction) of the cushion body by 10% or more, preferably 20% or more, most preferably 30% or more.

[0095] The applied pattern of parallel lines can vary at least once, and preferably twice, across the z-direction.

[0096] According to another embodiment, the extruded molten beads solidify without contacting two or more previously formed layers. Thus, these solidified beads are at least partially free-floating, also known as "bridging." In particular, thermoplastic polyurethanes containing C3 ether units, such as polypropylene glycol units, are suitable for this embodiment due to their low Shore A hardness, rapid viscosity increase upon cooling but not too rapid crystallization, and therefore good adhesive properties.

[0097] According to another embodiment, between 2 and 1000 (preferably between 5 and 400, more preferably between 10 and 200) co-moving extrusion nozzles are used simultaneously to produce the article.

[0098] According to another embodiment, the article has a width of 30 cm to 300 cm, a length of 30 cm to 300 cm, a height of 2 cm to 30 cm, or a combination of at least two of the aforementioned dimensions.

[0099] According to another embodiment, the article has a compression strength according to DIN EN ISO 3386-1:2015-10 at 40% compression in a first spatial direction and in a second spatial direction, wherein the compression strength in the first spatial direction is 150% or more (preferably 200% or more, more preferably 250% or more) of the compression strength in the second spatial direction. Such an article is easier to store under compression, for example as a mattress in a box.

[0100] According to another embodiment, the molten beads are extruded at least once onto the fabric. The fabric may be breathable or may remain attached to the finished article. The fabric may also be a distance fabric or a 3D fabric, as described in the introduction of this disclosure.

[0101] The present invention also provides a deformable article comprising a thermoplastic elastomer obtainable by the method according to the present invention, having a density of 60 g / l to 120 g / l (preferably 60 g / l to 110 g / l) and a compressive strength at 40% compression of 1 kPa to 9 kPa (preferably 1.5 kPa to 8 kPa, more preferably 2 kPa to 6 kPa). Without wishing to be limited by this statement, the article may be described as a thermoplastic open-cell cushioning article. The article may be used in hospital and nursing home beds. Seating in vehicles, particularly long-distance vehicles, is another preferred application area. The advantages of the deformable article of the present invention are particularly well utilized in applications such as its breathability, which cannot be achieved with conventional foams.

[0102] The article may be, for example, a mattress, cushion, or pillow. The article may have excellent washability and low odor, for example, in a washing machine at 30°C, 40°C, or 50°C. Because TPE materials offer good chemical resistance to common disinfectants, the cleaning process may include common disinfectant cleaning additives and solvents such as isopropanol and ethanol. Because the article offers uniform and / or separable material properties, it can be easily recycled by thermal recycling, shredding and re-pelletization, or chemical / hydrolytic recycling.

[0103] As already outlined in connection with the method according to the present invention, the thermoplastic elastomer of the article is preferably a thermoplastic polyurethane. It is also preferred that the thermoplastic polyurethane contains C3 ether units, such as polypropylene glycol units. An example of such a material is a TPU having a composition containing more than 80% by weight of polypropylene glycol, MDI, butanediol, and hexanediol. The polypropylene glycol used in the TPU may have a number-average molecular weight Mn between 800 and 4000 g / mol and a polydispersity Mw / Mn of 1.5 or less.

[0104] As also outlined above in connection with the method according to the present invention, the article may have a width of 30 cm to 300 cm, a length of 30 cm to 300 cm, a height of 2 cm to 20 cm, or a combination of at least two of the aforementioned dimensions. The article may also have a compression strength according to DIN EN ISO 3386-1:2015-10 at 40% compression in the first spatial direction and the second spatial direction, wherein the compression strength in the first spatial direction is 150% or more (preferably 200% or more, more preferably 250% or more) of the compression strength in the second spatial direction. Such an article is easier to store under compression, for example as a mattress in a box.

[0105] The article may be designed to have high tensile strength in the XY direction and lower strength in the z direction. The tear strength in the Z direction is 30% or less, preferably 20% or less, most preferably 15% or less, but 1%, preferably 2% or more, most preferably 3% or more of the tensile strength in the XY direction. This is very advantageous as it allows the mattress to be separated along the layers in a controlled manner for recycling reasons and to separate different TPE materials used within one build.

[0106] The article may have a compression set of less than 30%, preferably less than 20%, and most preferably less than 10% size after 1000 repeated compressions of 40% within a 24 hour period. Compression set measurements are based on DIN EN ISO 3386-1:2015-10 and are performed on a Zwick Retro, 2kN power load cell on a 10cm*10cm*5cm sample at 0.05kPa pretension, 23°C and 50% humidity.

[0107] The article may have low odor emission, VOC emission and FOC properties.

[0108] Even in an unassembled state, the article can have better flame retardancy than standard non-flame retardant polyurethane foam materials due to the thermoplastic material, and can not burn in the flame tests according to EN 597-1:2015 and DIN EN 597-2:2016-03.

[0109] The article may provide a gap to receive the fan and / or sensor, which may then be installed in the gap designed for that purpose.

[0110] The article may comprise a ventilation device for passing air through at least a part of the deformable body. In the simplest case, air is directed from the surroundings through at least a part of the deformable article, thereby allowing easy removal of moisture excreted as a result of perspiration from a person using the device while sitting or lying on the article. This may increase comfort when sitting or lying.

[0111] The perceived comfort can be further increased by using one or more heating elements to heat the air above room temperature (temperature >20°C) or by using one or more cooling elements to cool the air (temperature ≦25°C).

[0112] According to one embodiment, the article further comprises an actuator and / or a sensor.

[0113] The present invention further provides an open-cell cushioning material comprising a deformable body. The device of the present invention may be, for example, a seat cushion, a pillow, a mattress, upholstered furniture, or a vehicle seat. The device may comprise not only the deformable body of the present invention, which functions as a mattress or cushioning area, but also active and passive elements. Passive elements are components such as frames, joints, and rollers. Active elements may be servomotors, e.g., motors for adjusting seat shape, sensors, or other elements that provide a desired function.

[0114] According to another embodiment, the article further comprises an element within the deformable article adapted to be filled with a pressurized fluid, which can take the form of parallel or perpendicular linear spaces across the cushion, and which can be inflated by means of an inflatable tube, by expanding or contracting the tube with a pressurized gas or liquid, in order to change the cushioning behavior of the body of the invention as required.

[0115] The present invention will now be further described with reference to the following figures and examples, without intending to be limited thereby.

[0116] Materials used: TPU A: Thermoplastic polyurethane containing polypropylene glycol units and having a Shore hardness of 80A according to DIN ISO 7619. Available as Desmopan 6080A from Covestro Deutschland AG.

[0117] TPU B: Thermoplastic polyurethane containing polypropylene glycol units and having a Shore hardness of 45A according to DIN ISO 7619. Available as Desmopan 6045A prototype from Covestro Deutschland AG.

[0118] TPU C: Thermoplastic polyurethane containing polypropylene glycol units and having a Shore hardness of 65A according to DIN ISO 7619. Available as Desmopan 6064A from Covestro Deutschland AG.

[0119] TPU D: Thermoplastic polyurethane containing ether units and having a Shore hardness of 85D according to DIN ISO 7619. Available as Desmopan 9385DU from Covestro Deutschland AG.

[0120] TPU E: Thermoplastic polyurethane containing ether units and having a Shore hardness of 65D according to DIN ISO 7619. Available as Desmopan 9868DU from Covestro Deutschland AG.

[0121] TPU F: Ester-based thermoplastic polyurethane with a Shore hardness of 60D according to DIN ISO 7619. Available as Desmopan 460 from Covestro Deutschland AG.

[0122] PLA E: Polylactic acid with a Shore hardness of 80D according to DIN ISO 7619. Available as PLA 3D850 from filament2print.com.

[0123] Build pattern: "Rect." is a rectangular pattern shown in FIG. 1, "Gyr." is a gyroid pattern shown in FIG. 2, "Triang." is a triangular pattern shown in FIG. 3, "Honeyc." is a honeycomb pattern shown in FIG. 4, the "Wiggle" pattern is shown in FIG. 5, and the "Grid" pattern is shown in FIG. 6.

[0124] Creating a deformable body: All materials were used as pellets and extruded on a Tumaker Pro Dual 3D Printer with one or two independent pellet heads to simulate parallel extrusion in accordance with the present invention on a laboratory scale. Unless otherwise noted, the extruder nozzle was kept at 250°C, and the build plate and build room temperature were not heated or cooled and were measured to be below 30°C. Other experimental conditions are listed in the table below.

[0125] The fabrication files were based on G-code created via Fullcontrol GCODE Designer, or, in the case of the present example, via pre-fabricated fill structures. The G-code was manually imported and run on a Tumaker Pro Dual 3D Printer. Print times were calculated from the G-code files.

[0126] In all tables, examples of the present invention are marked with an asterisk ("*"). In the tables, "Line Distance" is the average distance between adjacent extruded beads. "Temperature" refers to the temperature of the extruder nozzle. "Average Bead Application Rate" is calculated from the G-code instructions. "Extruded Bead Diameter" is calculated as described above. "Stable Structure" means that the structure exhibits sufficient dimensional stability under compressive strength testing, resulting in greater than 95% height retention after measurement. "As-designed Structure" means that the structure is generated according to the G-code instructions, and the resulting structure largely reflects the dimensions of the structure that can be visualized by common G-code viewers, such as programs readily available in Cura, Simplify 3D, or nc-viewer. "Compressive Strength at 40% Compression, 4th Cycle" was determined according to DIN EN ISO 3386-1:2015-10. "Tensile Set after 4 Cycles" was determined 5 minutes after the cyclic compression measurement as the delta value between the height before and after measurement relative to the compressed value.

[0127] "Layer overlap" refers to the contact of each layer of an article with its preceding lower layer by a specified percentage of its associated average extruded molten bead diameter. This number can be determined by extracting the extrusion path of each layer from the G-code file and converting it to a vector file (e.g., by importing the code file into spreadsheet software and exporting the corresponding xy plot as a Scalable Vector Graphics (.SVG) file). The next step is to import the resulting vector file into a CAD program (e.g., Autodesk Fusion 360). The thickness of the imported line is defined as the average extruded bead diameter. The overlap of two consecutive layers within the CAD program can then be determined. The resulting overlap area is divided by the area of ​​the upper layer and multiplied by 100, thus giving the layer overlap value in percent. [Table 1]

Table 2

Table 3

Table 4

Table 5

Table 6

Table 7

Table 8

Claims

1. 1. A method for manufacturing a deformable article, comprising extruding a plurality of thermoplastic elastomer molten beads in parallel, layer by layer, from a plurality of co-moving extrusion nozzles in accordance with machine-readable instructions; the machine-readable instructions are output of software for generating machine-readable instructions, and the input for generating the instructions does not include a representation of a three-dimensional computer-aided design (3D-CAD) model of the article to be manufactured or a software-generated sliced ​​layer of the 3D-CAD model of the article to be manufactured; The extrusion nozzle moves at a nozzle speed, the extruded molten bead has a diameter, and the product of the nozzle speed and the diameter of the extruded bead is 25 mm ２ / s or more 80mm ２ / s or less, The thermoplastic elastomer has a Shore A hardness according to DIN ISO 7619 of 45 or more and 94 or less, the extruded molten beads form a layer in the article having a height of at least 0.3 mm and not more than 0.55 mm; the diameter of the extruded beads is greater than 100% and less than or equal to 145% of the height of the layer formed by the beads; Each extrusion nozzle has an inner diameter of 0.3 mm or more and 0.7 mm or less; adjacent extruded beads in one layer have an average distance from each other of 6 mm to 20 mm, each layer of said article contacts, on average, its preceding underlying layer by no more than 60% of the average diameter of its associated extruded molten bead; the article comprises a wall formed by extruding the thermoplastic elastomer and a void, thereby establishing a density and a compressive strength according to DIN EN ISO 3386-1:2015-10 at 40% compression of the article; whereby the article is formed having a density of 60 g / l or more and less than 120 g / l and a compressive strength at 40% compression according to DIN EN ISO 3386-1:2015-10 of 1 kPa or more and 9 kPa or less.

2. The method of claim 1 , wherein the input to the software that generates the machine-readable instructions comprises a user-defined segment of a path of travel for the extrusion nozzle, the definition comprising spatial coordinates and extrusion instructions.

3. The method of claim 1 or 2, wherein the output of the software that generates the machine-readable instructions comprises G-code.

4. The method according to any one of claims 1 to 3, wherein the thermoplastic elastomer is a thermoplastic polyurethane.

5. 5. The method of any one of claims 1 to 4, wherein the cross-section of the article comprises repeating units of straight segments at an angle to each other, repeating units of curved segments, repeating units of curved segments at an angle to each other, or a combination of two or more of the repeating units.

6. The method of any one of claims 1 to 5, wherein a first cross section of the article is different from a second cross section parallel to the first cross section.

7. The method of claim 1 , wherein the first cross-section of the article corresponds to a rotated second cross-section of the article.

8. 8. The method of any one of claims 1 to 7, wherein the extruded molten bead solidifies without contacting two or more previously formed layers.

9. 9. The method of any one of claims 1 to 8, wherein between 2 and 1000 co-moving extrusion nozzles are used simultaneously to produce the article.

10. 10. The method of any one of claims 1 to 9, wherein the article has a width of 30 cm to 300 cm, a length of 30 cm to 300 cm, a height of 2 cm to 30 cm, or a combination of at least two of said dimensions.

11. 11. The method according to any one of claims 1 to 10, wherein the article has a compressive strength according to DIN EN ISO 3386-1:2015-10 at 40% compression in a first spatial direction and in a second spatial direction, wherein the compressive strength in the first spatial direction is 150% or more of the compressive strength in the second spatial direction.

12. The method of any one of claims 1 to 11, wherein the molten beads are extruded onto the fabric at least once.

13. 13. A deformable article comprising a thermoplastic elastomer, said article having a density of ≧60 g / l and less than 120 g / l and a compressive strength at 40% compression of ≧1 kPa and ≦9 kPa according to DIN EN ISO 3386-1:2015-10, and obtainable by the method according to any one of claims 1 to 12.

14. The article of claim 13 further comprising an actuator and / or a sensor.

15. 15. The article of claim 13 or 14, further comprising an element within the deformable article adapted to be inflated by a pressurized fluid.

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