COMPOSITE OBJECT COMPRISING A BODY AND A FOAM, AND METHOD FOR PRODUCTION THEREOF

Abstract

The present invention relates to novel anisotropic composite materials and processes for production thereof. The composite materials are based on the crosslinking of polyisocyanates and feature good weathering stability.

Claims

1.-16. (canceled)

17. A composite article comprising a body and a solid foam, wherein the body has been produced by means of an additive manufacturing process and has at least a positive fit to the foam, wherein the material of the body is different from that of the foam.

18. The composite article as claimed in claim 17, wherein the body comprises a spatial network of node points joined to one another by struts and a space present between the struts, the space present between the struts is at least partially occupied by a solid polymer foam and the body is at least partially formed from a polymeric material different from the polymer foam.

19. The composite article as claimed in claim 18, wherein the body is at least partially formed from a polymeric material selected from the group of: thermosetting polyurethanes, epoxides, polyacrylates, polyurethane acrylates, thermoplastic polyamides, thermoplastic polyesters, polyvinyl acetate, polystyrene, polyethylene, polypropylene, polyoxymethylene, polyvinyl chloride, polyurethanes, polyacrylates, polyether ether kethones, polyetherimides, 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, sulfur- or oxygen-crosslinked elastomer/rubber raw materials and a combination of at least two of the aforementioned materials.

20. The composite article as claimed in claim 19, wherein the polymeric material is a thermoplastic elastomer and has a melting range (DSC, differential scanning calorimetry; second heating at a heating rate of 5 K/min) of ?20? C. to ?240? C., has a Shore hardness according to DIN ISO 7619-1 of ?40 A to ?80 Shore D and has a melt volume rate (MVR) according to ISO 1133 (240? C., 10 kg) of ?25 to ?250 cm.sup.3/10 min.

21. The composite article as claimed in claim 19, wherein the elastomer is a thermoplastic elastomer and has a melting range (DSC, differential scanning calorimetry; second heating at a heating rate of 5 K/min) of ?20? C. to ?240? C., has a Shore hardness according to DIN ISO 7619-1 of ?40 Shore A to ?80 Shore D, has a melt volume rate (MVR) according to ISO 1133 (10 kg) at a temperature T of 5 to 15 cm.sup.3/10 min and exhibits a change in the melt volume rate (10 kg) at an increase of this temperature T by 20? C. of ?90 cm.sup.3/10 min

22. The composite article as claimed in claim 19, wherein the polymeric material is a thermoplastic elastomer and has a melting range (DSC, differential scanning calorimetry; 2nd heating at a heating rate of 5 K/min) of ?20? C. to ?100? C. and a magnitude of complex viscosity |?*| (determined by viscometry measurement in the melt with a cone/plate oscillation shear viscometer at 100? C. and a shear rate of 1/s) of ?10 Pas to ?1 000 000 Pas.

23. The composite article as claimed in claim 19, wherein the polymeric material is a thermoplastic polyurethane elastomer obtainable from the reaction of a polyisocyanate component and a polyol component, wherein the polyol component comprises a polyesterpolyol having a no-flow point (ASTM D5985) of ?25? C.

24. The composite article as claimed in claim 18, wherein the composite article (1, 2) has a compression set after 10% compression (DIN ISO 815-1) of ?2%.

25. The composite article as claimed in claim 19, wherein the polymeric material is a crosslinked polyacrylate crosslinked by means of free-radical crosslinking proceeding from liquid starting products in the presence of photoinitiators by the action of actinic radiation.

26. The composite article as claimed in claim 18, wherein in the body (10, 20) the struts (100) have an average length of ?200 ?m to ?200 mm, the struts (100) have an average thickness of ?100 ?m to ?5 mm and the body has in at least one spatial direction a compressive strength (40% compression, DIN EN ISO 3386-1:2010-09) of ?10 to ?1000 kPa.

27. The composite article as claimed in claim 18, wherein in the body the node points are distributed in a periodically repeating manner in at least a portion of the volume of the body.

28. The composite article as claimed in claim 18, wherein in the body the spatial density of the node points in a first region of the body is different from the spatial density of the node points in a second region of the body.

29. The composite article as claimed in claim 17, wherein the body is fully embedded in the foam so that the body does not protrude from the foam at any point.

30. The use of a composite article as claimed in claim 17 as a supporting element and/or mounting element.

31. A process for producing a composite article as claimed in claim 17 comprising the steps of: I) producing a body by means of an additive manufacturing process; II) contacting the body with a foam-forming composition, wherein the composition at least partially penetrates into the interior of the body; III) forming a foam to obtain the composite article.

32. A process for producing a composite article as claimed in claim 18 comprising the steps of: I) producing a body by means of an additive manufacturing process, wherein the body comprises a spatial network of node points joined to one another by struts and a space present between the struts; II) contacting the body with a reaction mixture which reacts to afford a polymer foam, wherein the reaction mixture at least partially penetrates into the space between the struts of the body; III) reacting the reaction mixture to afford a polymer foam to obtain the composite article, wherein the body is at least partially formed from a polymeric material different from the polymer foam.

Description

[0104] The present invention is more particularly elucidated using the figures which follow and with reference to preferred embodiments without, however, being limited thereto. In the drawings:

[0105] FIG. 1 shows a body in a first view

[0106] FIG. 2 shows the body from FIG. 1 in another view

[0107] FIG. 3 shows a composite article according to the invention

[0108] FIG. 4 shows a further body

[0109] FIG. 5 shows a further composite article according to the invention

[0110] FIG. 1 shows a body 10 such as is employable for the production of a composite article according to the invention in a perspective view with a spatial network of node points 200 joined to one another by struts 100. Present between the struts 100 is the space 300. Present at the edges of the body 10 are truncated node points 201 whose struts project only into the interior of the body 10. FIG. 2 shows the same body 10 in an isometric view.

[0111] The node points 200 may be uniformly distributed in the body 10 in at least a portion of the volume thereof. Likewise said node points 200 may be nonuniformly distributed in at least a portion of the volume thereof. It is also possible for the body 10 to comprise one or more subvolumes in which the node points 200 are uniformly distributed and to comprise one or more subvolumes in which the node points 200 are nonuniformly distributed.

[0112] Depending on the construction of the network of struts 100 and node points 200 in the body 10 certain mechanical properties may also be a function of the spatial direction in which they are determined on the body. This is the case for example for the body 10 shown in FIGS. 1 and 2. Along the spatial directions corresponding to the base vectors of the elementary cell the compressive strength and the tan ? value in particular may be different than, for example, along a spatial direction which includes all three base vectors as components.

[0113] The space 300 may account for ?50% to ?99%, preferably ?55% to ?95%, more preferably ?60% to ?90%, of the volume of the body 10. When the density of the starting material for the body and the density of the body itself are known this parameter is easily determinable.

[0114] It is preferable when the node points 200 are distributed in a periodically repeating manner in at least a portion of the volume of the body 10. When the node points 200 are distributed in a periodically repeating manner in a volume this may be described using the terms of crystallography. The node points may be arranged according to the 14 Bravais lattices: simple cubic (Sc), body-centered cubic (bcc), face-centered cubic (fcc), simple tetragonal, body-centered tetragonal, simple orthorhombic, base-centered orthorhombic, body-centered orthorhombic, face-centered orthorhombic, simple hexagonal, rhombohedral, simple monoclinic, base-centered monoclinic and triclinic. The cubic lattices sc, fcc and bcc are preferred.

[0115] Persisting with the crystallographic perspective the number of struts 100 by means of which one node point 200 is connected to other node points may be regarded as the coordination number of the node point 200. The average number of struts 100 that emanate from the node points 200 may be ?4 to ?12 but it is also possible to achieve coordination numbers that are unusual or impossible in crystallography. For the determination of the coordination numbers, truncated node points on the outer face of the body, as labelled with reference numerals 201 in FIG. 1, are disregarded.

[0116] The presence of unusual coordination numbers or coordination numbers that are impossible in crystallography may be achieved in particular when the body is produced by means of additive manufacturing techniques. It is likewise possible for a first group of node points 200 to have a first average number of struts 100 and a second group of node points to have a second average number of struts 100, wherein the first average number is different from the second average number.

[0117] In the body 10 shown in FIGS. 1 and 2 the node points 200 are arranged in a body-centered cubic lattice. The coordination number thereof and thus the average number of struts emanating therefrom is 8.

[0118] The average minimum angle between adjacent struts 100 may be ?30? to ?140?, preferably ?45? to ?120?, more preferably ?50? to ?100?. In the case of the body 10 shown in FIGS. 1 and 2 the minimum angle between the struts 100 is about 70.5? at all points (arccos(?)) as is derivable from trigonometric considerations of the angle between the spatial diagonals of a cube.

[0119] FIG. 3 shows a plan view of a composite article 1 according to the invention. Starting from the body shown in FIGS. 1 and 2 a polymer foam 301 is now present in the interior of the body in the space between the struts 100. The outside surfaces of the composite article 1 shown in FIG. 3 continue to show truncated node points having the reference numerals 201 and 202.

[0120] The construction of the body may, at least in the cases of uniform arrangement of the node points 200 in the space, also be described as a result of penetration of hollow channels through a previously solid body 20. Thus having reference to FIG. 4 the space 300 may be in the form of interpenetrating first 310, second 320 and third 330 channel groups, wherein a multiplicity of individual channels 311, 321, 331 run parallel to one another within their respective channel group and the first channel group 310, the second channel group 320 and the third channel group 330 run in different spatial directions.

[0121] The body 20 shown in FIG. 4 has a higher spatial density of node points 200 in the section thereof shown on the left-hand side of the figure than in the section thereof shown on the right-hand side of the figure. For improved clarity; the abovementioned embodiment is discussed with reference to the section shown on the right-hand side. An array 310 of individual channels 311, whose direction is indicated by arrows, runs through the body perpendicularly to the surface of the body facing it. It will be appreciated that not just the three channels identified by reference numerals but all channels extending through the body at right angles to the face specified are concerned.

[0122] The same applies to the channels 321 of the channel group 320 and the channels 331 of the channel group 330 which run perpendicularly to one another and perpendicularly to the channels 311 of the first channel group 310. The material of the body remaining between the interpenetrating channels 311, 321, 331 forms the struts 100 and node points 200.

[0123] It is possible for the individual channels 311, 321, 331 to have a polygonal or round cross-section. Examples of polygonal cross-sections are triangular, quadrangular, pentagonal and hexagonal cross-sections. FIG. 4 shows square cross sections of all channels 311, 321, 331. Also possible is that within the first 310, second 320 and third 330 channel group the individual channels 311, 321, 331 each have the same cross section. This is shown in FIG. 4.

[0124] Likewise possible is that the cross section of the individual channels 311 of the first channel group 310, the cross section of the individual channels 321 of the second channel group 320 and the cross section of the individual channels 331 of the third channel group 330 are different from one another. For example the channels 311 may have a square cross section, the channels 321 may have a round cross section and the channels 331 may have a hexagonal cross section. The cross section of the channels determines the shape of the struts 100, so that in the case of different cross-sections different characteristics of the body 20 according to spatial directions may also be achieved.

[0125] In one variant the spatial density of the node points 200 in a first region of the body 20 may be different from the spatial density of the node points 200 in a second region of the body 20. This is shown schematically in the one-piece body 20 according to FIG. 4. As mentioned previously the body 20 shown therein has a higher spatial density of node points 200 in the section thereof shown on the left-hand side of the figure than in the section thereof shown on the right-hand side of the figure. Only every second node point 200 of the left-hand section forms a strut 100 to a node point 200 of the right-hand section,

[0126] FIG. 5 shows a plan view of a composite article 2 according to the invention. Starting from the body shown in FIG. 4 a polymer foam 301 is now present in the interior of the body in the space between the struts 100. The outside surfaces of the composite article 2 shown in FIG. 5 continue to show truncated node points having the reference numerals 201 and 202.

[0127] A further example of a composite article according to the invention not shown in the figures would be a ball such as for example a football. A body produced by 3-D printing as the inner structure having a treelike branching network of struts and node points is foam-filled in a spherical foaming mold so as to form an integral foam having a closed surface. The foam may have a compressive strength (40% compression, DIN EN ISO 3386-1:2010-09) of ?100 kPa and a density of ?30 g/l.