High-strength eTPU

Abstract

Foamed pellets contain a thermoplastic polyurethane obtainable or obtained by reacting a polyisocyanate composition (IC), containing at least one aliphatic diisocyanate having a number-average molecular weight of less than 200 g/mol, at least one chain extender (CE1), and a polyol composition (PC). A process can be used for the production of such foamed pellets. The foamed pellets can be used for the production of a molded body.

Claims

1-13. (canceled)

14: Foamed pellets, comprising a thermoplastic polyurethane obtainable or obtained by reacting at least components (i) to (iii): (i) a polyisocyanate composition (IC), (ii) at least one chain extender (CE1), and (iii) a polyol composition (PC), wherein the polyisocyanate composition (IC) comprises at least one aliphatic diisocyanate having a number-average molecular weight of less than 200 g/mol, and, if the polyisocyanate composition (IC) comprises further isocyanates, the further isocyanates are present in the polyisocyanate composition (IC) at an amount in the range from 0.1% to 20% by weight, wherein the chain extender (CE1) is a diamine or a diol having a molecular weight of less than 500 g/mol, and wherein an average diameter of beads of the foamed pellets is from 0.2 to 20 mm.

15: The foamed pellets according to claim 14, wherein the at least one aliphatic diisocyanate is a linear diisocyanate having an even number of carbon atoms.

16: The foamed pellets according to claim 14, wherein the at least one aliphatic diisocyanate is hexamethylene diisocyanate (HDI).

17: The foamed pellets according to claim 14, wherein the chain extender (CE1) is selected from the group consisting of propane-1,3-diol, ethane-1,2-diol, butane-1,4-diol, hexane-1,6-diol, and HQEE.

18: The foamed pellets according to claim 14, wherein the polyol composition (PC) comprises a polyol selected from the group consisting of a polyetherol, a polyesterol, a polycaprolactone polyol, and a polycarbonate polyol.

19: The foamed pellets according to claim 14, wherein the polyol composition (PC) comprises a polyol selected from the group consisting of a polytetrahydrofuran having a number-average molecular weight Mn in the range from 500 g/mol to 2000 g/mol.

20: A process for the production of foamed pellets, comprising: (i) providing a composition (C1) comprising a thermoplastic polyurethane, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least components (a) to (c): (a) a polyisocyanate composition (IC), (b) at least one chain extender (CE1), and (c) a polyol composition (PC), wherein the polvisocyanate composition (IC) comprises at least one aliphatic diisocyanate having a number-average molecular weight of less than 200 g/mol, and, if the polyisocyanate composition (IC) comprises further isocyanates, the further isocyanates are present in the polyisocyanate composition (IC) at an amount in the range from 0.1% to 20% by weight, wherein the chain extender (CE1) is a diamine or a diol having a molecular weight of less than 500 g/mol; (ii) impregnating the composition (C1) with a blowing agent under pressure; and (iii) expanding the composition (C1) by a pressure decrease, wherein an average diameter of beads of the foamed pellets is from 0.2 to 20 mm.

21: Foamed pellets, obtained or obtainable by a process according to claim 20.

22: A molded body, comprising the foamed pellets according to claim 21.

23: A method of producing the molded body according to claim 22, the method comprising: fusing or bonding the foamed pellets to one another.

24: The molded body according to claim 22, wherein the molded body is a shoe sole, a part of a shoe sole, a bicycle saddle, a cushioning, a mattress, an underlay, a grip, a protective film, or a component in automobile interiors and exteriors.

25: The foamed pellets according to claim 21, wherein the foamed pellets are molded into a ball, sports equipment, a floor covering, or a wall paneling.

26: A hybrid material, comprising a matrix composed of a polymer (PM) and the foamed pellets according to claim 21.

27: A molded body, comprising the foamed pellets according to claim 14.

28: A method of producing the molded body according to claim 27, the method comprising: fusing or bonding the foamed pellets to one another.

29: The molded body according to claim 27, wherein the molded body is a shoe sole, a part of a shoe sole, a bicycle saddle, a cushioning, a mattress, an underlay, a grip, a protective film, or a component in automobile interiors and exteriors.

30: The foamed pellets according to claim 14, wherein the foamed pellets are molded into a ball, sports equipment, a floor covering, or a wall paneling.

31: A hybrid material, comprising a matrix composed of a polymer (PM) and the foamed pellets according to claim 14.

Description

EXAMPLES

[0204] 1. The Following Feedstocks were Used: [0205] Polyol 1: polyether polyol having an OH number of 112.2 and exclusively primary OH groups (based on tetramethylene oxide, functionality: 2) [0206] Chain extender 1: butane-1,4-diol [0207] Isocyanate 1: aliphatic isocyanate (hexamethylene 1,6-diisocyanate) [0208] Isocyanate 2: aromatic isocyanate (methylene diphenyl 4,4′-diisocyanate) [0209] Catalyst 1: tin(II) dioctoate (50% in DOA) [0210] Catalyst 2: tin (II) dioctoate (10% in DOA) [0211] Antioxidant 1: sterically hindered phenol [0212] Antioxidant 2: sterically hindered phenol [0213] TPU crosslinker 1: Thermoplastic polyurethane having an NCO content of 8.5% and a functionality of 2.05 by means of addition of oligomeric MDI

[0214] 2. Production of the TPU [0215] The following examples TPU 1 to 4, specified hereafter, were produced in a ZSK58 MC twin-screw extruder from Coperion, having a processing length of 48D (12 barrels). The melt was discharged from the extruder by means of a gear pump. After filtration of the melt, the polymer melt was processed by means of underwater pelletization into pellets which were dried continuously at 40-90° C. in a heated fluidized bed. [0216] The polyol, the chain extender and the diisocyanate and also any catalyst were metered into the first zone. The supply of further additives, as described above, is effected in zone 8. [0217] The barrel temperatures are in the range from 150−230° C. The discharge of the melt and underwater pelletization are effected at melt temperatures of 210-230° C. The screw speed is between 180 and 240 min.sup.−1. The throughput is in the range from 180-220 kg/h.

[0218] The amounts used are summarized in table 1.

TABLE-US-00001 TABLE 1 Synthesis examples: TPU1 TPU2 TPU3 TPU4 Polyol 1 [parts] 100 100 100 100 Chain extender 1 [parts] 11.49 31.96 16.20 20.88 Isocyanat 1 [parts] 38.48 76.21 Isocyanat 2 [parts] 70.00 83.00 Catalyst 1 [mL/min] 0.25 Catalyst 2 [mL/min] 0.5 0.16 0.16 Antioxidant 1 [parts] 1.66 1.66 Antioxidant 2 [parts] 1.88 2.06

[0219] 3. Production of the eTPU

[0220] 3.1 The expanded beads made of the thermoplastic polyurethanes (table 1) were produced using a twin-screw extruder having a screw diameter of 44 mm and a length-to-diameter ratio of 42 with connected melt pump, a start-up valve with screen changer, a die plate and an underwater pelletization system. The thermoplastic polyurethane was dried prior to processing at 80° C. for 3 h in order to obtain a residual moisture content of less than 0.02% by weight. In addition to the thermoplastic polyurethane, a TPU which had been admixed with diphenylmethane 4,4′-diisocyanate having an average functionality of 2.05 in a separate extrusion process, was added. [0221] The respectively used thermoplastic polyurethane and also the TPU crosslinker 1 were each metered into the intake of the twin-screw extruder separately via gravimetric metering devices. [0222] After metering the materials into the intake of the twin-screw extruder, they were melted and mixed. The blowing agents CO2 and N2 were subsequently added via one injector each. The remaining extruder length was used for the homogeneous incorporation of the blowing agents into the polymer melt. After the extruder, the polymer/blowing agent mixture was forced using a gear pump (GP) via a start-up valve with screen changer (SV) into a die plate (DP), and divided in the die plate into strands which were cut into pellets in the pressurized cutting chamber, through which a temperature-controlled liquid flowed, of the underwater pelletization system (UWP), and transported away with the water and expanded in the process. [0223] A centrifugal dryer was used to ensure separation of the expanded beads from the process water. [0224] The total throughput of the extruder, polymers and blowing agents, was 40 kg/h. Table 2 lists the amounts used of the polymers and of the blowing agents. Here, the polymers always constitute 100 parts, while the blowing agents are counted in addition, so that total compositions above 100 parts are obtained.

TABLE-US-00002 TABLE 2 Parts of the polymers and blowing agents metered, where the polymers/solids always result in 100 parts and the blowing agents are counted in addition Amount of the Amount of the functionalized Amount Amount TPU TPU used TPU of CO2 of N2 Name used [parts] [parts] [parts] [parts] eTPU TPU 1 99.1 0.9 2.1 0.2 eTPU 2 TPU 1 99.1 0.9 2.1 0.2 [0225] The temperatures used for the extruder and downstream devices and also the pressure in the cutting chamber of the UWP are listed in table 3.

TABLE-US-00003 TABLE 3 Temperature data of the installation components Temperature Temperature Temperature Temperature Water Water range in the range of range of range of pressure temperature extruder the GP the SV the DP in the UWP in the UWP (° C.) (° C.) (° C.) (° C.) (bar) (° C.). eTPU1 210-240 200 200 220 15 45 eTPU2 210-240 200 200 220 15 45 [0226] After separation of the expanded pellets from the water by means of a centrifugal dryer, the expanded pellets are dried at 60° C. for 3 h in order to remove the remaining surface water and any possible moisture present in the bead and not to distort further analysis of the beads. [0227] Table 4 lists the bulk densities resulting for the individual expanded thermoplastic polyurethanes after the drying.

TABLE-US-00004 TABLE 4 Data regarding the eTPU Bulk density (g/l) eTPU1 162 eTPU2 160

[0228] 3.2 In addition to the processing in the extruder, expanded beads were also produced in an impregnation tank. For this purpose, the tank was filled to a filling level of 80% with the solid/liquid phase, with the phase ratio being 0.32.

[0229] The solid phase can be seen here to be the TPU1 or the TPU2 and the liquid phase can be seen to be the mixture of water with calcium carbonate and a surface-active substance. The blowing agent (butane) was injected into the gas-tight tank, which had previously been purged with nitrogen, onto this mixture at the amount indicated in table 5 based on the solid phase (TPU1 or TPU 2). The tank was heated while stirring the solid/liquid phase and nitrogen was injected in a defined manner up to a pressure of 8 bar at a temperature of 50° C. Heating was subsequently continued up to the desired impregnation temperature (IMT). When the impregnation temperature and the impregnation pressure had been reached, the tank was depressurized after a given holding time via a valve. The precise production parameters of the experiments and also the bulk densities achieved are listed in table 5.

TABLE-US-00005 TABLE 5 Production parameters and bulk densities achieved for the impregnated materials TPU 1 and TPU 2 Blowing agent Holding time concentration based (range of on the amount IMT −5° C. to Bulk of solid phase IMT +2° C.) IMT density Name TPU (% by weight) (min) (° C.) (g/l) eTPU3 TPU1 24 5.4 112 127 eTPU4 TPU1 24 5.6 112.5 97 eTPU5 TPU1 24 5.2 114 72 eTPU6 TPU2 24 3.8 133 132 eTPU7 TPU2 24 3.9 134 95 eTPU8 TPU2 24 4.1 135 69

[0230] 4. Fusion and Mechanical Properties

[0231] 4.1 Production of Molded Bodies by Steam Fusion [0232] The expanded pellets were subsequently fused to give square slabs having a side N length of 200 mm and a thickness of 10 mm or 20 mm by contacting with steam in a molding machine from Kurtz ersa GmbH (Energy Foamer). For the thickness of the slabs, the fusion parameters only differ with respect to the cooling. The fusion parameters for the different materials were selected such that the slab side of the final molding that faced the movable side (MII) of the mold had a minimum number of collapsed eTPU beads. Gap steaming was optionally also effected through the movable side of the mold. Regardless of the experiment, a cooling time of 120 s for a slab thickness of 20 mm and 100 s for a slab of thickness 10 mm from the fixed side (MI) and the movable side of the mold was always established at the end. Table 6 lists the respective steaming conditions as vapor pressures. The slabs are stored in an oven at 70° C. for 4 hours.

TABLE-US-00006 TABLE 6 Steaming conditions (vapor pressures) Gap steaming Cross-steaming Pressure Pressure Pressure Pressure Name [bar] MI [bar] MII [bar] MI [bar] MII eTPU1 0.5 0.7 1.3 0 eTPU2 0.5 0.7 1.3 0

TABLE-US-00007 TABLE 7 Mechanical properties Sample eTPU 1 eTPU 1 eTPU 2 eTPU 2 Sample ref. 10 mm 20 mm 10 mm 20 mm Foam density [g/cm.sup.3] 0.313 0.272 0.317 0.272 Tear propagation [N/mm] 11.4 12.4 resistance (trouser test piece) Dimensional Change in −0.7 −0.7 −0.6 −0.8 stability test length [%] Change in 27.7 28.4 28.1 23.3 height [%] Tensile test Tensile 2.17 2.15 strength [MPa] Elongation at 148 149 tensile strength [%] Elongation at 205 203 tensile strength (traverse) [%] Foam 0.308 0.314 density [g/cm.sup.3] Compressive Compressive 56 42 strength strength 10 [kPa] Compressive 509 495 strength 50 [kPa] Foam 0.263 0.26 density [g/cm.sup.3] Tear propagation [N/mm] 5.3 4.7 resistance (split tear) Rebound [%] 77 77 resilience

[0233] 4.2 Comparative Experiments Rebound Resilience

[0234] In order to highlight the better rebound resilience of the material claimed, two TPUs (TPU3 and TPU4), which have a hard phase of MDI but have identical Shore hardnesses as the TPU 1 and the TPU 2, were likewise foamed in an impregnation process as described above.

[0235] For this purpose, the tank was filled to a filling level of 80% with the solid/liquid phase, with the phase ratio being 0.32.

[0236] The solid phase can be seen here to be the TPU3 or the TPU4 and the liquid phase can be seen to be the mixture of water with calcium carbonate and a surface-active substance. The blowing agent (butane) was injected into the gas-tight tank, which had previously been purged with nitrogen, onto this mixture at the amount indicated in table 8 based on the solid phase (TPU3 or TPU4). The tank was heated while stirring the solid/liquid phase and nitrogen was injected in a defined manner up to a pressure of 8 bar at a temperature of 50° C. Heating was subsequently continued up to the desired impregnation temperature (IMT). When the impregnation temperature and the impregnation pressure had been reached, the tank was depressurized after a given holding time via a valve.

TABLE-US-00008 TABLE 8 Production parameters and bulk densities achieved for the impregnated materials Blowing agent Holding time concentration based (range of on the amount IMT −5° C. to Bulk of solid phase IMT +2° C.) IMT density Name TPU (% by weight) (min) (° C.) (g/l) Comp. TPU3 24 6.3 140 80 eTPU1 Comp. TPU4 24 4.5 156 71 eTPU2

[0237] The expanded pellets were subsequently fused to give square slabs having a side length of 200 mm and a thickness of 20 mm by contacting with steam in a molding machine from Kurtz ersa GmbH (Energy Foamer). The fusion parameters for the different materials were selected such that the slab side of the final molding that faced the movable side (MII) of the mold had a minimum number of collapsed eTPU beads. Regardless of the experiment, a cooling time of 40 s from the fixed side (MI) and the movable side of the mold was always established at the end. Table 9 lists the respective steaming conditions. The slabs are subsequently stored in an oven at 70° C. for 4 hours.

TABLE-US-00009 TABLE 9 Fusion parameters Cross steam Autoclave steam Pressure Pressure Pressure Pressure Time MI MII Time MI MII Name [s] [bar] [bar] [s] [bar] [bar] Comp. eTPU1 3 3.2 3.2 48 3.2 3.2 Comp. eTPU2 3 3.6 3.6 48 3.6 3.6 eTPU5 7 0.8 0.8 32 1.0 1.0 eTPU8 7 1.6 1.6 32 1.6 1.6

[0238] The rebound resilience was subsequently determined for all samples according to DIN EN ISO 8307:2008-03 (table 10)

TABLE-US-00010 TABLE 10 Mechanical analysis Foam density Rebound Name DIN EN ISO 845 [g/cm.sup.3] DIN EN ISO 8307 [%] Comp. 0.197 52.6 eTPU1 Comp. 0.163 36.5 eTPU2 eTPU5 0.188 69.8 eTPU8 0.154 70.6

[0239] 5. Measurement Methods: [0240] Measurement methods that can be used for the material characterization include the following: DSC. DMA, TMA, NMR, FT-IR, GPC

TABLE-US-00011 Mechanical properties (eTRU) Foam density DIN EN ISO 845: 2009 October Tear propagation resistance DIN EN ISO 8067: 2009 June Dimensional stability test ISO 2796: 1986 August Tensile test ASTM D5035: 2011 Rebound resilience DIN 53512: 2000 April (Table 7) DIN EN ISO 8307: 2008 March (Table 10)

CITED LITERATURE

[0241] WO 94/20568 A1 [0242] WO 2007/082838 A1 [0243] WO 2017/030835 A1 [0244] WO 2013/153190 A1 [0245] WO 2010/010010 [0246] “Kunststoffhandbuch Band 7, Polyurethane” [Plastics Handbook, volume 7, Polyurethanes], Carl Hanser Verlag, 3rd edition, 1993, chapter 3.1. [0247] WO 2007/082838 A1 [0248] WO 2013/153190 A1 [0249] Saechtling (Ed.), Kunststoff-Taschenbuch [Plastics Handbook], 27.sup.th edition, Hanser-Verlag, Munich 1998, chapters 3.2.1 and 3.2.4 [0250] WO 2014/150122 A1 [0251] WO 2014/150124 A1 [0252] EP 1 979 401B1 [0253] US 2015/0337102 A1 [0254] EP 2 872 309B1 [0255] EP 3 053 732 A1 [0256] WO 2016/146537 A1