Particle foams consisting of an aromatic polyester-polyurethane multi-block copolymer

Abstract

Foamed pellets contain a block copolymer. The block copolymer is obtained or obtainable by a process involving the reaction of an aromatic polyester (PE-1) with an isocyanate composition (IC), containing at least one diisocyanate, and with a polyol composition (PC). The polyol composition (PC) contains at least one aliphatic polyol (P1) having a number-average molecular weight ≥500 g/mol. 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

1-17. (canceled)

18. Foamed pellets comprising a block copolymer, wherein the block copolymer is obtained or obtainable by a process comprising: (a) providing an aromatic polyester (PE-1); and (b) reacting the aromatic polyester (PE-1) with an isocyanate composition (IC) comprising at least one diisocyanate, and with a polyol composition (PC), wherein the polyol composition (PC) comprises at least one aliphatic polyol (P1) having a number-average molecular weight ≥500 g/mol and a diol (D1) having a number-average molecular weight <500 g/mol, wherein the aromatic polyester (PE-1) is obtainable or obtained by reacting at least one aromatic polyester haying a melting point in the range from 160 to 350° C. and at least one diol (D2), at a temperature of greater than 200° C., and wherein an average diameter of beads of the foamed pellets is between 0.2 to 20 mm.

19. The foamed pellets according to claim 18, wherein the reaction to obtain the aromatic polyester (PE-1) is continuous.

20. The foamed pellets according to claim 18, wherein the reaction to obtain the aromatic polyester (PE-1) is effected in an extruder.

21. The foamed pellets according to claim 18, wherein the at least one aromatic polyester is selected from the group consisting of polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN).

22. The foamed pellets according to claim 18, wherein the diol (D1) is selected from the group consisting of 1,2-ethylene glycol, propane-1,3-diol, butane-1,4-diol, and hexane-1,6-diol.

23. The foamed pellets according to claim 18, wherein the polyol (P1) is selected from the group consisting of polyetherols, polyesterols, polycarbonate alcohols, and hybrid polyols.

24. The foamed pellets according to claim 18, wherein the at least one diisocyanate is used in a molar amount of at least 0.9, based on the alcohol groups of a sum total of the components of the polyol composition (PC) and of the aromatic polyester (PE-1).

25. The foamed pellets according to claim 18, wherein the at least one diisocyanate is selected from the group consisting of diphenylmethane 2,2-, 2,4′- and 4,4′-diisocyanate (MDI); tolylene 2,4- and 2,6-diisocyanate (TDI); methylene dicyclohexyl 4,4′-, 2,4′- and 2,2′-diisocyanate (H12MDI); hexamethylene diisocyanate (HDI); and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI).

26. A process for the production of foamed pellets, comprising: (i) providing a composition (C1) comprising a block copolymer, wherein the block copolymer is obtained or obtainable by a process comprising: (a) providing an aromatic polyester (PE-1); and (b) reacting the aromatic polyester (PE-1) with an isocyanate composition (IC) comprising at least one diisocyanate, and with a polyol composition (PC), wherein the polyol composition (PC) comprises at least one aliphatic polyol (P1) having a number-average molecular weight ≥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 between 0.2 to 20 mm.

27. Foamed pellets, obtained or obtainable by a process according to claim 26.

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

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

30. The molded body according to claim 28, 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.

31. The foamed pellets according to claim 27, wherein the foamed pellets are molded into a ball, sports equipment, a floor covering, or a wall paneling.

32. A hybrid material, comprising a matrix composed of a polymer (PM) and the foamed pellets according to claim 27.

33. A molded body, comprising the foamed pellets according to claim 18.

34. A method of producing the molded body according to claim 33, the method comprising: fusing or bonding the foamed pellets to one another.

35. The molded body according to claim 33, 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.

36. The foamed pellets according to claim 18, wherein the foamed pellets are molded into a ball, sports equipment, a floor covering, or a wall paneling.

37. A hybrid material, comprising a matrix composed of a polymer (PM) and the foamed pellets according to claim 18.

Description

EXAMPLES

[0253] 1. The Following Feedstocks were Used: [0254] Polyester 1: polybutylene terephthalate (PET) having a weight-average molecular weight of 60 000 g/mol [0255] Polyol 2: polyether polyol having an OH number of 174.7 and exclusively primary OH groups (based on tetramethylene oxide, functionality: 2) [0256] Polyol 3: polyether polyol having an OH number of 112.2 and exclusively primary OH groups (based on tetramethylene oxide, functionality: 2) [0257] Polyol 4: mixture of 53.33% polyol 3 and 46.67% polyol 5 [0258] Polyol 5: polyether polyol having an OH number of 55.8 and exclusively primary OH groups (based on tetramethylene oxide, functionality: 2) [0259] Polyol 6: polyester polyol having an OH number of 56 and exclusively primary OH groups (based on hexanediol, butanediol and adipic acid, functionality: 2) [0260] Polyol 7: polyester polyol having an OH number of 38 and exclusively primary OH groups (based on methyl-propanediol-butanediol adipate, functionality: 2) [0261] Chain extender 1: butane-1,4-diol [0262] Isocyanate 1: aromatic isocyanate (methylene diphenyl 4,4′-diisocyanate) [0263] Isocyanate 2: aliphatic isocyanate (hexamethylene 1,6-diisocyanate) [0264] Catalyst 1: dioctoate (pure) [0265] Antioxidant 1: sterically hindered phenol [0266] Hydrolysis stabilizer 1: polymeric carbodiimide [0267] Hydrolysis stabilizer 2: epoxidized soybean oil [0268] Hydrolysis stabilizer 3: polymeric carbodiimide [0269] Wax 1: amide wax [0270] 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

[0271] 2. Polymer Synthesis Example

[0272] 2.1 Description of the Urethane-Comprising Polymer Production—General Description

[0273] The following examples polymers 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.

[0274] 2.2 Examples of Urethane-Comprising Polymers 1 to 4

[0275] The Ultradur B4500 polybutylene terephthalate from BASF SE was metered into the first zone. After the melting of the PBT, a monomeric diol-butane-1,4-diol in examples polymers 1 to 4- or else a low molecular weight polyol, and also optionally a catalyst, was fed into the third zone for the transesterification of the PST. After transesterification had taken place, the further reaction components, such as diisocyanate and longer-chained polyols, were added into the fifth zone. The supply of further additives, as described above, is effected in zone 8.

[0276] The barrel temperatures for the intake, zone 1, are 150° C. Melting of the PBT and transesterification in zones 2-5 are effected at temperatures of 250-300° C. Synthesis of the polymer in zones 6-12 takes place at barrel temperatures of 240-210° 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 150-220 kg/h.

[0277] Following the synthesis, the polymer obtained is subjected to underwater or strand pelletization and subsequently dried.

[0278] 2.3 Examples of Urethane-Comprising Polymers 5 to 7

[0279] The polyester (PBT) is fed into the first barrel of a ZSK58 twin-screw extruder from Coperion with a processing length of 48D. After the melting of the polyester, the polyol, and any catalyst present therein, is added in barrel 3. The transesterification is effected at barrel temperatures of 250-300° C., before the diisocyanate is added to the reaction mixture in the fifth barrel. The molar mass increase is effected downstream at barrel temperatures of 100-230° C. Following the synthesis, the polymer obtained is subjected to underwater or strand pelletization and subsequently dried.

[0280] The amounts used are summarized in table 1.

TABLE-US-00001 TABLE 1 Synthesis examples: Polymer 1 Polymer 2 Polymer 3 Polymer 4 Polymer 5 Polymer 6 Polymer 7 Polyester 1 25.43 16.30 22.00 30 60 60 60 [parts] Polyol 2 36 [parts] Polyol 3 56.54 45.55 36 [parts] Polyol 4 36 [parts] Polyol 6 58.46 33.80 [parts] Polyol 7 33.80 [parts] Chain 1.21 1.10 3.52 4.80 extender 1 [parts] Iso 1 [parts] 11.41 10.56 9.19 14.61 7.03 Iso 2 [parts] 16.16 16.80 Antioxidant 0.5 0.5 1 1 [parts] Concentrate 3 1 [parts] Hydrolysis 2 1 stabilizer 1 [parts] Hydrolysis 0.1 0.1 0.5 stabilizer 2 Hydrolysis 1.5 0.95 0.95 0.95 stabilizer 3 Wax 1 0.5 Catalyst 1 0.005 0.005 0.96 0.96

[0281] The properties of the thermoplastic polyurethanes that were produced by the continuous synthesis are summarized in table 2.

TABLE-US-00002 TABLE 2 Examples of properties: Polymer Polymer Polymer 5 6 7 Shore A Shore D 50 48 49 Tensile strength 31 34 37 [MPa] Elongation at break 630 580 640 [%] Tear propagation 113 117 111 resistance [kN/m] Abrasion [mm.sup.3] 22 24 32

[0282] 3. Examples for the Production of Foam Beads

[0283] The expanded beads made of the products (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 crosslinker 1 was added to some experiments.

[0284] This crosslinker is a thermoplastic polyurethane that had been admixed with diphenylmethane 4,4′-diisocyanate having an average functionality of 2.05 in a separate extrusion process. The residual NCO content is >5%.

[0285] The respectively used polymer and also the crosslinker 1 were each metered into the intake of the twin-screw extruder separately via gravimetric metering devices.

[0286] 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.

[0287] A centrifugal dryer was used to ensure separation of the expanded beads from the process water.

[0288] The total throughput of the extruder, polymers and blowing agents, was 40 kg/h. Table 3 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-00003 TABLE 3 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 Amount of the of the Amount Amount Polymer TPU used functionalized of CO2 of N2 Name used [parts] TPU [parts] [parts] [parts] Expanded Polymer 99 1 2.9 0.90 polymer 1 1 Expanded Polymer 99.4 0.6 2.2 0.21 polymer 2 2 Expanded Polymer 99.4 0.6 1.8 0.10 polymer 3 2 Expanded Polymer 100 0 1.5 0.10 polymer 4 3 Expanded Polymer 99.1 0.9 1.6 0.1.5 polymer 5 4 Expanded Polymer 99.4 0.6 1.6 0.15 polymer 6 4 Expanded Polymer 100 0 1.7 0.15 polymer 7 5 Expanded Polymer 100 0 1.6 0.15 polymer 8 6 Expanded Polymer 100 0 1.6 0.15 polymer 9 7

[0289] The temperatures used for the extruder and downstream devices and also the pressure in the cutting chamber of the UWP are listed in table 4.

TABLE-US-00004 TABLE 4 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 in the UWP (° C.) (° C.) (° C.) (° C.) UWP (bar) (° C.). Expanded 170-220 170 170 220 12.5 45 polymer 1 Expanded 160-220 160 160 220 15 40 polymer 2 Expanded 160-220 160 160 220 15 40 polymer 3 Expanded 210-220 210 210 220 15 40 polymer 4 Expanded 210-230 210 210 220 15 40 polymer 5 Expanded 220-230 230 230 220 15 50 polymer 6 Expanded 220-240 230 230 220 15 40 polymer 7 Expanded 210-230 210 210 220 15 40 polymer 8 Expanded 220-240 230 230 220 15 40 polymer 9

[0290] 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,

[0291] Table 5 lists the bulk densities resulting for the individual expanded products after the drying.

TABLE-US-00005 TABLE 4 Data regarding the expanded polymer Bulk density (g/1) Expanded polymer 1 132 Expanded polymer 2 152 Expanded polymer 3 180 Expanded polymer 4 160 Expanded polymer 5 162 Expanded polymer 6 118 Expanded polymer 7 141 Expanded polymer 8 128 Expanded polymer 9 130

[0292] 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 0.31.

[0293] The solid phase can be seen here to be polymer 3 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, into this mixture at the amount indicated in table 6 based on the solid phase (polymer 3). 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 6.

TABLE-US-00006 TABLE 6 Production parameters and achieved bulk densities of impregnated polymer 3 Blowing agent Holding time concentration based (range of 1MT − Bulk on the amount of solid 5° C. to IMT + IMT density Name phase (% by weight) 2° C.) (min) (° C.) (g/l) Expanded 24 22 100 167 polymer 10 Expanded 24 21 110 134 polymer 11

[0294] 4. Fusion and Mechanical Properties

[0295] 4.1 Production of Molded Bodies by Steam Fusion

[0296] The expanded pellets were subsequently fused to give square slabs having a side 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 beads. Gap steaming 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 (M1) and the movable side of the mold was always established at the end. Table 7 lists the respective steaming, conditions as vapor pressures. The slabs are stored in an oven at 70° C. for 4 hours.

TABLE-US-00007 TABLE 7 Steaming conditions (vapor pressures) Gap steaming Cross-steaming Pressure [bar] Pressure [bar] Pressure [bar] Pressure [bar] Name MI MII MI MII Expanded 2 2 2 2 polymer 2 Expanded 2 2 2 2 polymer 3 Expanded 0 0.5 1.3 1.1 polymer 4 Expanded 0 0.75 1.3 1.1 polymer 5 Expanded 0 0.4 0 0 polymer 6

[0297] 4.2 Production of Molded Bodies by Radiofrequency Fusion

[0298] The expanded pellets were subsequently fused by means of radiofrequency waves to give square slabs having a side length of 200 mm and a thickness of 10 mm in a molding machine from Kurtz ersa GmbH (RE Foamer). To this end, approx. 100 g of the beads were weighed out and placed into a Teflon mold and spread as flat as possible. The mold was closed to 10 mm with a Teflon plate and the expanded pellets compressed. The radiofrequency fusion at 24 MHz was started, the set voltage (setpoint value: 5.9 to 6.5 kV) was reached in 2 seconds. The beads were fused at this voltage for 30 to 50 seconds. As a result of the irradiation of the beads, the mold heated up to approx. 100° C. The mold was subsequently cooled down to 40 to 50° C.: at room temperature without external cooling, before the fused slab was removed. The machine parameters are summarized in table 7. Before the slabs are tested mechanically, they are stored in an oven at 70° C. for 4 hours.

TABLE-US-00008 TABLE 8 Parameters for the radiofrequency fusion Starting temperature Name Charge [g] [° C.] Voltage [kV] Time [s] Expanded 116 42.4 6.0 32 polymer 4 Expanded 100 52.8 6.5 40 polymer 5-1 Expanded 100 52.8 6.5 40 polymer 5-2 Expanded 100 52.5 5.9 32 polymer 6

[0299] 4.3 Mechanical Properties

TABLE-US-00009 TABLE 8a Tear propagation Foam resistance density ETPU AA ETPU DIN U-10-121-206 EN ISO 845 Tear DIM Stab. int. Foam propagation ISO 2796 Sample density resistance Delta l Delta h Sample Fusion type thickness [g/cm.sup.3] [N/mm] [%] [%] Expanded Steam 10 mm 0.267 polymer 2 Expanded Steam 10 mm 0.256 polymer 3 Expanded Steam 10 mm 0.285 7.2 −3.4 46.1 polymer Expanded Steam 20 mm −4.3 33.7 polymer 4 Expanded Steam 10 mm 0.252 7.6 −1.9 33.9 polymer 5 Expanded Steam 20 mm −1.9 23.9 polymer 5 Expanded RF 10 mm 0.287 9.7 −1.5 9.4 polymer 4 Expanded RF 10 mm 0.257 14.3 −2.1 1.7 polymer 5-1 Expanded RF 10 mm 0.244 10.2 −1.7 6 polymer 5-2 Expanded RF 10 mm 0.263 0.1 −2.4 0 polymer 6

TABLE-US-00010 TABLE 8b Split Tear ETPU AA Rebound Tensile test ETPU U-10- resilience based on ASTM D 5035 Indentation hardness 121-206 comp. DIN Elongation ETPU AA U-10-121-206 Tear 53512 Tensile (tensile Elongation Foam Indentation Indentation Foam propagation Rebound strength strength) at break density hardless 10 hardness 50 density resistance resilience Sample [MPa] [%] [%] [g/cm.sup.3] [kPa] [kPa] [g/cm.sup.3] [N/mm] [%] Expanded 8 186 0.276 60 polymer 2 Expanded 6 157 0.251 56 polymer 3 Expanded 0.59 102 119 0.276 polymer Expanded 13 229 0.257 1.8 76 polymer 4 Expanded 0.88 110 122 0.247 polymer 5 Expanded 17 219 0.221 2 75 polymer 5 Expanded 0.95 234 287 0.285 polymer 4 Expanded 1.12 228 287 0.251 polymer 5-1 Expanded 0.88 182 184 0.246 polymer 5-2 Expanded 0.59 93 99 0.262 polymer 6

[0300] 5. Measurement Methods:

[0301] Measurement methods that can be used for the material characterization include the following: DSC, DMA, TMA, NMR, GPC

TABLE-US-00011 Mechanical properties (TPU) Shore D hardness DIN 7619-1:2012-02 Modulus of elasticity DIN 53504:2017-03 Tensile strength DIN 53504:2017-03 Elongation at break DIN 53504:2017-03 Tear propagation resistance DIN ISO 34-1, B:2016-09 Abrasion DIN 4649:2(314-03 Mechanical properties (expanded polymer) Foam density DIN EN ISO 845:2009-10 Tear propagation resistance DIN EN ISO 8067:2009-06 Dimensional stability test ISO 2796:1986-08 Tensile test ASTM D5035:2011 Rebound resilience DIN 53512:2000-4

CITED LITERATURE

[0302] WO 94/20568 A1

[0303] WO 2007/082838 A1

[0304] WO 2017/030835 A1

[0305] WO 2013/153190 A1

[0306] WO 2010/010010 A1

[0307] EP 0 656 397 A1

[0308] EP 1 693 394 A1

[0309] “Kunststoffhandbuch” [Plastics Handbook], volume 7, “Polyurethane” [Polyurethanes], Carl Hanser Verlag, 3rd edition, 1993, chapter 3.1

[0310] WO 2014/150122 A1

[0311] WO 2014/150124 A1

[0312] EP 1979401 B1

[0313] US 2015/0337102 A1

[0314] EP 2 872 309 B1

[0315] EP 3 053 732 A11

[0316] WO 2016/146537

[0317] Piechota and Röhr in “Integralschaumstoff” [Integral Foam], Carl-Hanser-Verlag, Munich, Vienna, 1975, or in “Kunststoff-Handbuch” [Plastics Handbook], volume 7, “Polyurethane” [Polyurethanes], 3rd edition, 1993, chapter 7