COMPOSITE ARTICLE COMPRISING A STRUCTURED POROUS BODY AND A FOAM AND A PROCESS THE PRODUCTION OF A STRUCTURED POROUS BODY AND A PARTICLE FOAM

Abstract

The present invention relates to a process for the production of a composite article comprising a structured porous body (PB) and a particle foam (PF), wherein the provided structured porous body (PB) is inserted into a mould (M) and the mould (M) is filled with expanded foam beads (EFB) so that the expanded foam beads (EFB) are in contact with each other and the structured porous body (PB) is at least partially in contact with the expanded foam beads (EFB). Then, the expanded foam beads (EFB) are thermally welded, wherein the particle foam (PF) is built and the composite article is obtained. Moreover, the present invention relates to a composite article obtained by this process, as well as to a composite article comprising a structured porous body (PB) and a particle foam (PF). The present invention further relates to the use of the inventive composite articles in the shoe industry, in the sports and leisure sector, in vehicle construction, in the medical sector, in mechanical engineering and in the logistics sector. Furthermore, the present invention relates to a composite article comprising a structured porous body (PB) and a foam (F), wherein the structured porous body (PB) and the foam (F) comprise the same polymer (P).

Claims

1.-19. (canceled)

20. A process for the production of a composite article comprising a structured porous body (PB) and a particle foam (PF), wherein the process comprises the following steps a) to d) a) providing the structured porous body (PB), b) inserting the structured porous body (PB) provided in step a) into a mould (M), c) filling the mould (M) with expanded foam beads (EFB) so that the expanded foam beads (EFB) are in contact with each other, and the structured porous body (PB) is at least partially in contact with the expanded foam beads (EFB), and d) thermally welding the expanded foam beads (EFB), wherein the particle foam (PF) is built and the composite article is obtained, wherein the expanded foam beads (EFB) comprise a thermoplastic elastomer (TPE).

21. The process according to claim 20, wherein the structured porous body (PB) i) comprises at least one thermoplastic or thermoset polymer (TP) selected from the group consisting of impact modified vinyl-aromatic copolymers, thermoplastic styrene-based elastomers (S-TPE), polyolefins (PO), aliphatic-aromatic copolyesters, polycarbonates, thermoplastic polyurethanes (TPU), polyamides (PA), polyphenylene sulphides (PPS), polyaryletherketones (PAEK), polysulfones and polyimides (PI), and/or ii) comprises a three-dimensional network of node points and a void volume, wherein the node points are joined to another by struts and the void volume is present between the struts, and/or iii) is produced by a three-dimensional (3D) printing process, and/or iv) is a lattice or a triply periodic minimal surface (TPMS), and/or v) fits exactly into the mould (M), or fills only part of the mould (M).

22. The process according to claim 20, wherein the expanded foam beads (EFB) i) comprise a thermoplastic polyurethane, and/or ii) have an average diameter of 0.2 to 20 mm, and/or iii) have a melting point T.sub.M(EFB)≤300° C.

23. The process according to claim 21, wherein the 3D printing process is a sintering process.

24. The process according to claim 23, wherein the sintering process comprises the following steps i) and ii) i) providing a layer of a sinter powder (SP), and ii) sintering the layer of the sinter powder (SP) provided in step i).

25. The process according to claim 20, wherein the expanded foam beads (EFB) are thermally welded by steam, microwave, variotherm or radio frequency.

26. The process according to claim 20, wherein the mould (M) comprises a fixed part (FP) and a moveable part (MP), and, in step b), the structured porous body (PB) is inserted either into the fixed part (FP) or into the moveable part (MP) of the mould (M).

27. The process according to claim 20, wherein the thermal welding in step d) is carried out by steaming the expanded foam beads (EFB) at a first temperature T.sub.1 which is above the softening temperature T.sub.S of the expanded foam beads (EFB).

28. The process according to claim 27, wherein the first temperature T.sub.1 in step d) is in the range from 90 to 200° C.

29. The process according to claim 20, wherein, between step b) and step c), a step e2) is carried out, in which the mould (M) is partially closed by moving the moveable part (MP) of the mould (M) so that a crack (C) is built between the fixed part (FP) and the moveable part (MP), wherein the thickness of the crack (C) is in the range from 5 to 24 mm.

30. The process according to claim 29, wherein the steaming of the expanded foam beads (EFB) according to step d) comprises the following steps d1) to d4) d1) steaming the expanded foam beads (EFB) through the crack (C), wherein the steam is supplied on the side of the moveable part (MP) of the mould (M) and exits the mould (M) on the side of the fixed part (FP), or the steam is supplied on the side of the fixed part (FP) of the mould (M) and exits the mould (M) on the side of the moveable part (MP), or the steam is subsequently supplied on the side of the moveable part (MP) and on the side of the fixed part (FP) and exits the mould (M) subsequently on the side of the fixed part (FP) and on the side of the moveable part (MP), respectively, d2) completely closing the mould (M) by further moving the moveable part (MP) of the mould (M), d3) steaming the expanded foam beads (EFB), wherein the steam is supplied on the side of the fixed part (FP) of the mould (M), or steaming the expanded foam beads (EFB), wherein the steam is supplied on the side of the moveable part (MP) of the mould (M), or steaming the expanded foam beads (EFB), wherein the steam is subsequently supplied on the side of the moveable part (MP) and on the side of the fixed part (FP) of the mould (M), and d4) steaming the expanded foam beads (EFB), wherein the steam is simultaneously supplied on the side of the fixed part (FP) and on the side of the moveable part (MP) of the mould (M).

31. The process according to claim 30, wherein i) in step d1), the expanded foam beads (EFB) are steamed with a steam pressure in the range from 0.7 to 2.0 bar, on the side of the fixed part (FP) and/or on the side of the moveable part (MP), and/or ii) in step d1), the expanded foam beads (EFB) are steamed for a time period in the range from 3 to 30 s, and/or iii) in step d3), the expanded foam beads (EFB) are steamed with a steam pressure in the range from 1.1 to 3.5 bar, on the side of the fixed part (FP), and/or iv) in step d3), the expanded foam beads (EFB) are steamed with a steam pressure in the range from 1.1 to 3.5 bar, on the side of the moveable part (MP), and/or v) in step d3), the expanded foam beads (EFB) are steamed for a time period in the range from 3 to 60 s, and/or vi) in step d4), the expanded foam beads (EFB) are steamed with an absolute steam pressure in the range from 1.3 to 3.5 bar, and/or vii) in step d4), the expanded foam beads (EFB) are steamed for a time period in the range from 3 to 80 s.

32. The process according to claim 20, wherein, between step b) and step c), a step e1) is carried out, in which the mould (M) is completely closed by moving the moveable part (MP) of the mould (M), wherein the steaming of the expanded foam beads (EFB) according to step d) comprises the following steps d3) and d4) d3) steaming the expanded foam beads (EFB), wherein the steam is supplied on the side of the fixed part (FP) of the mould (M), or steaming the expanded foam beads (EFB), wherein the steam is supplied on the side of the moveable part (MP) of the mould (M), or steaming the expanded foam beads (EFB), wherein the steam is subsequently supplied on the side of the moveable part (MP) and on the side of the fixed part (FP) of the mould (M), and d4) steaming the expanded foam beads (EFB), wherein the steam is simultaneously supplied on the side of the fixed part (FP) and on the side of the moveable part (MP) of the mould (M).

33. A composite article obtained by a process according to claim 20.

34. A composite article comprising a structured porous body (PB) and a particle foam (PF), wherein the structured porous body (PB) is obtained by a three-dimensional (3D) printing process and the particle foam (PF) comprises a thermoplastic elastomer (TPE), polystyrene (PS), ethylene vinyl acetate (EVA), polyolefin or a mixture thereof.

35. The composite article according to claim 34 used in the shoe industry, in the sports and leisure sector, in vehicle construction, in the medical sector, in mechanical engineering and in the logistics sector.

36. A composite article comprising a structured porous body (PB) and a particle foam (PF), wherein the structured porous body (PB) and the particle foam (PF) each comprise the same polymer (P), wherein the particle foam (PF) comprises a thermoplastic elastomer (TPE).

37. The composite article according to claim 36, wherein the structured porous body (PB) and the particle foam (PF) each consist of the same polymer (P).

Description

EXAMPLES

Inventive Examples E1 and E2

Production of Composite Articles

Step a) (Provision of the Structured Porous Bodies (PB))

[0123] Two lattices, designed in Rhino/Grasshopper, were generated. Therefore, a space of 200×200×20 mm was filled with a graph of diamond structure and different diameters were applied, e.g. for diamond-lattice (D 1 mm), a 1 mm diameter was applied to the graph. After exporting this structure, it was 3D-printed using an HP 5200 MJF printer and a thermoplastic polyurethane powder (Ultrasint® TPU01, BASF SE). After printing, the lattices were cleaned by dry air and sandblasting.

[0124] The generated lattices are listed in table 1.

TABLE-US-00001 TABLE 1 Lattice Type Lat 1 diamond-lattice (D 1 mm) Lat 2 gradient-lattice (D 0.7-2 mm)

Step b) (Insertion of the Structured Porous Body (PB))

[0125] For the production of the composite articles, a steam chest moulder, type Boost Energy Foamer K68 from company Kurtz Ersa GmbH, was used. The machine was equipped with a quadratic test plate mould (M) (dimension: 200×200×20 mm) which was made up of a fixed part (FP) and a movable part (MP). The 3D printed lattices were each inserted into the fixed part (FP) of the mould (M).

Step e2) (Partially Closing of the Mould (M))

[0126] After inserting the respective lattice into the fixed part (FP) of the mould (M), the mould (M) was partially closed by moving the moveable part (MP) of the mould (M) so that a crack (C) is built between the fixed part (FP) and the moveable part (MP) of the mould (M).

Step c) (Filling of the Mould (M))

[0127] Then, the mould (M) was filled with expanded foam beads (EFB) (expanded thermoplastic polyurethane foam beads Infinergy 200 MP, BASF SE) so that the expanded foam beads (EFB) are in contact with each other and the lattice is at least partially in contact with the expanded foam beads (EFB).

Step d1) (Crack Steaming)

[0128] After filling the mould (M) with the expanded foam beads (EFB), the expanded foam beads (EFB) were steamed through the crack (C), wherein the steam is supplied on the side of the moveable part (MP) of the mould (M) and exits the mould (M) on the side of the fixed part (FP).

Step d2)

[0129] Then, the mould (M) was completely closed by further moving the moveable part (MP) of the mould (M).

Step d3) (Cross Steaming)

[0130] After completely closing the mould (M), the expanded foam beads (EFB) were steamed, wherein the steam is supplied on the side of the fixed part (FP) of the mould (M).

Step d4) (Autoclave Steaming)

[0131] After the cross steaming, the expanded foam beads (EFB) were steamed again, wherein the steam is simultaneously supplied on the side of the fixed part (FP) and on the side of the moveable part (MP) of the mould (M).

Comparative Examples C1, C2 and C3

[0132] As reference, pure particle foam (PF) articles were also produced by a process comprising steps e2), c), d1), d2), d3) and d4), which means that no structured porous body (PB) was inserted into the mould (M).

[0133] In table 2, the composition of the different (composite) articles, the thickness of the crack (C), the crack steam pressure, the crack steaming time period, the cross steam pressure, the cross steam time period, the autoclave steam pressure and the autoclave steam time period are given.

TABLE-US-00002 TABLE 2 E1/E4 E2 E3 E5 (Lat 1 + (Lat 2 + (Lat 2 + (Lat 1 + ex- ex- ex- ex- C1 C2 C3 C4 C5 panded panded panded panded (Ex- (Ex- (Ex- (Ex- (Ex- thermo- thermo- thermo- thermo- panded panded panded panded panded plastic plastic plastic plastic thermo- thermo- thermo- thermo- thermo- PU PU PU PU plastic plastic plastic plastic plastic foam foam foam foam PU foam PU foam PU foam PU foam PU foam Example beads) beads) beads) beads) beads) beads) beads) beads) beads) Thickness 15 20 10 20 15 22 24 10 5 of the crack (C) [mm] Crack 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 steam pressure [bar] Crack 16 16 16 16 16 16 16 16 16 steaming time period [s] Cross 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 steam pressure [bar] Cross 30 30 30 30 30 30 30 30 30 steaming time period [s] Autoclave 1.3/1.8 1.3/1.8 1.3/1.8 1.3/1.8 1.3/1.8 1.3/1.8 1.3/1.8 1.3/1.8 1.3/1.8 steam pressure (fixed part/move- able part) [bar] Autoclave 10 10 10 10 10 10 10 10 10 steaming time period [s] Cooling 120/120 120/120 120/120 120/120 120/120 120/120 120/120 120/120 120/120 time period (fixed part/move- able part) [s]

[0134] The cooling water has a temperature of 17 to 23° C.

Characterization of the (Composite) Articles

[0135] Before testing, the (composite) articles were stored for at least 16 hours under standardized climate conditions (23±2° C. and 50±5% humidity). The testing was also carried out under standardized climate conditions.

Density and Density Distribution Δ

[0136] Six specimens with the dimension 50×50 mm were sawn out of the (composite) article with a band saw. The specimens were taken from the positions shown in FIG. 1. The (composite) article is shown from the point of view as it would be still inside the fixed part (FP) of the mould (M).

[0137] For each specimen, density was calculated by determining its mass (precision scale; accuracy: ±0.001 g) and dimensions (length, thickness and width, calliper; accuracy: ±0.01 mm, contact pressure 100 Pa, value was only measured once in the middle of the specimen). The density distribution Δ of all specimens was calculated using the standard deviation σ and the mean x (equations 1-3).

[00001]$\begin{array}{cc}\overline{x}=\frac{1}{n}.Math.x& \left(1\right)\end{array}$$\begin{array}{cc}\sigma =\frac{.Math.{\left(x-\overline{x}\right)}^2}{\left(n-1\right)}& \left(2\right)\end{array}$$\begin{array}{cc}\Delta =\frac{\sigma }{\stackrel{\_}{x}}.Math.100\%,& \left(3\right)\end{array}$

where n is the number of specimens (n=6) and x is the calculated density of the individual specimen.

Compression Hardness

[0138] For determination of the compression behaviour of the (composite) articles, specimens with the dimensions 50×50 mm×original thickness of the plate (in general 20 mm, but thickness can vary slightly due to shrinkage, skin is not removed) were taken from the (composite) articles by a band saw. Specimens were taken from the same positions presented in FIG. 1.

[0139] For each specimen, the mass (precision scale; accuracy: ±0.001 g), as well as the length and width (calliper; accuracy: ±0.01 mm, contact pressure 100 Pa, value was only measured once in the middle of the specimen) was measured.

[0140] Compression behaviour was then measured with a 50 kN force transducer (class 1 according to DIN EN ISO 7500-1:2018-06), a crosshead travel encoder (class 1 according to DIN EN ISO 9513:2013) and two parallel pressure plates (diameter 2000 mm, maximum permissible force 250 kN, maximum permissible surface pressure 300 N/mm.sup.2) without holes. For determining the density of the specimen, the measured mass, length and width were entered into the test specifications of the software of the test machine from company Zwick. The thickness of the specimen was determined by the universal test machine via the traverse path measuring system (accuracy: ±0.25 mm).

[0141] The measurement itself was carried out with a test speed of 50 mm/min and a pre-force of 1 N. The force in kPa was recorded at a stint of 10, 25, 50 and 75%. The values of the 1st cycle were used for evaluation. In order to evaluate the compression hardness at 75%, the sample must be compressed to 76%.

[0142] The results of the test are summarized in table 3.

Hydraulic Impact Test (HIT)

[0143] Compression behaviour under dynamic conditions was measured from the whole (composite) articles (dimension 200×200 mm×original thickness of the plate (in general 20 mm, but thickness can vary slightly due to shrinkage, skin is not removed) by using the HIT procedure according to Bruckner et al., Polyurethane-foam midsoles in running shoes—Impact energy and damping, Procedia engineering, 2 for short-term testing (100 load cycles).

[0144] The measurement was carried out using a servo-hydraulic tensile-compression test machine. The test set-up consists of a crowned punch, which is aligned at an angle of 90° to the fixed base of the (composite) article to be tested. The load spectrum is derived from measurements of the ground reaction force occurring during walking. The analysis of the resulting curve shows that the rear foot area of a runner is loaded with about twice the body weight when hitting the ground at a running speed of 3.5±0.1 m/s. A force-time curve is plotted in the testing machine according to these results. This reflects the first force peak (ground contact of the rear foot) of the biomechanical loads occurring for an average runner. The mechanical running shoe tests are based on the higher reliability and the significantly lower expenditure of time compared to test person tests. The aim of this mechanical test is limited to the realistic reproduction of the vertical force component during the contact of the rear foot with the ground.

[0145] The short-term test is performed over 100 load cycles. The result is the force and deformation curve of the 100th cycle (recorded at a frequency of 100 Hz) and is shown in FIG. 3. For running shoes, four parameters are of interest in the evaluation which are described below and shown in FIG. 2: [0146] Stiffness I: represents a parameter for the perceived hardness of a running shoe when stationary. This is determined for running shoes between 200-400 N—based on 0.5 times the mass of an average runner of 75 kg. [0147] Stiffness II: is a parameter for the perceived hardness of the running shoe in the landing phase of a step. This is determined for running shoes between 1,000-1,500 N. [0148] Energy loss: the proportion of the energy introduced that is absorbed by the material and dissipated as heat. The energy loss is calculated from the difference in the areas under the force-deformation curve of the loading and unloading phases (hysteresis curve). [0149] Max. Deformation: maximum punch penetration depth

[0150] Although the method was developed specifically for running shoes, it can also be used for the initial characterisation of new materials based on test plates such as the (composite) articles. For shoe applications in general, all running shoe specific parameters are of interest. But also for other applications where the material is used as a damping or vibration decoupling element, the test is especially interesting to investigate the energy loss.

[0151] The results of the test are summarized in table 4.

TABLE-US-00003 TABLE 3 E1 E2 E3 (Lat 1 + (Lat 2 + (Lat 2 + C1 C2 C3 expanded expanded expanded (Expanded (Expanded (Expanded thermo- thermo- thermo- thermo- thermo- thermo- plastic PU plastic PU plastic PU plastic PU plastic PU plastic PU Example foam beads) foam beads) foam beads) foam beads) foam beads) foam beads) Density (Position 1) 330 330 — 324 — — [g/L] Density (Position 2) 334 350 — 322 — — [g/L] Density (Position 3) 335 373 — 330 — — [g/L] Density (Position 4) 340 329 — 331 — — [g/L] Density (Position 5) 331 409 — 332 — — [g/L] Density (Position 6) 329 361 — 320 — — [g/L] Density distribution 1.2 8.4 — 1.6 — — [%] Compression hardness 492 462 — — — — at 50% compression (Position 1) [kPa] Compression hardness 507 539 — — — — at 50% compression (Position 2) [kPa] Compression hardness 513 672 — — — — at 50% compression (Position 3) [kPa] Compression hardness 534 771 — — — — at 50% compression (Position 4) [kPa] Compression hardness 508 948 — — — — at 50% compression (Position 5) [kPa] Compression hardness 495 621 — — — — at 50% compression (Position 6) [kPa] Compression hardness 6021 5073 — — — — at 75% compression (Position 1) [kPa] Compression hardness 6399 6976 — — — — at 75% compression (Position 2) [kPa] Compression hardness 6536 9938 — — — — at 75% compression (Position 3) [kPa] Compression hardness 6996 12268 — — — — at 75% compression (Position 4) [kPa] Compression hardness 6353 14584 — — — — at 75% compression (Position 5) [kPa] Compression hardness 6047 8775 — — — — at 75% compression (Position 6) [kPa]

[0152] As can be seen from table 3, by using a lattice with a gradient in diameter a stiffness gradient can be achieved. By this, compression hardness at 50% compression of the stiffest specimen can be 105% higher than the value of the softest specimen tested for one plate, wherein the density of the stiffest specimen is only 24% higher compared to the softest. For a compression of 75% the effect is even bigger as the highest compression hardness is increased by 187% compared to the lowest.

TABLE-US-00004 TABLE 4 Example E4 E5 (Lat 1 + (Lat 1 + C4 C5 expanded expanded (Expanded (Expanded thermo-plastic thermo-plastic thermo-plastic thermo-plastic PU foam beads) PU foam beads) PU foam beads) PU foam beads) Lat 1 Density [g/L] 319 350 306 317 50 Stiffness 1 [kN/mm] 0.09 0.10 0.08 0.07 0.17 Stiffness 2 [kN/mm] 0.36 0.39 0.29 0.29 1.87 Energy loss [J] 0.8 0.9 1.0 1.0 1.2 Dampening [%] 17.4 19.0 16.4 16.1 48.0

[0153] In this measurement, the pure insert shows the behaviour of a very flexible foam, i.e. the material shows an high compression even at low forces and at even higher compression a sudden increases in stiffness. Thus the lattice (Lat 1) already shows a high “stiffness I” and a much higher “stiffness II” compared to the E-TPU (C4 and C5). The combination of E-TPU and lattice, however, shows a similar force deflection curve as the pure E-TPU, whereby the “stiffness I” hardly changes compared to the E-TPU, i.e. one would have the same feeling when putting on a shoe. However, a higher “stiffness II” can be achieved with the same density. Too soft (stiffness II) E-TPU soles are perceived by many as unstable when walking. So one could achieve a higher stability without making the shoe heavier. In addition, energy loss and damping are almost not changed by the insertion of the grid, although the grid alone has very high damping values, for example.