PROCESS FOR PREPARING POLYURETHANES HAVING A HIGH REACTION ENTHALPY

Abstract

The invention relates to a multi-stage process for the continuous preparation of thermoplastic polyurethanes by reacting one or more aliphatic, cycloaliphatic and/or araliphatic diols with one or more aliphatic, cycloaliphatic and/or araliphatic diisocyanates, wherein the total reaction enthalpy is ≤−500 kJ/kg over all the process stages at a molar ratio of diol to diisocyanate of 1.0:1.0.

Claims

1. A continuous solvent-free multistage process for preparing thermoplastic polyurethanes by reacting the following components: A) one or more diols, B) one or more diisocyanates including aliphatic, cycloaliphatic and/or araliphatic diisocyanates, C) optionally one or more catalysts, and D) optionally further auxiliaries or additives, where at least one of the one or more diols of component A has a molecular weight of from 62 g/mol to 250 g/mol, wherein at least one hydroxy-terminated prepolymer is formed from a total amount or a first portion of component A and a first portion of component B in at least one process stage of the multistage process, wherein a sum total of all portions of component A or a sum total of all portions of component B over all process stages of the multistage process together is a total amount of component A or component B used, wherein components A and B are selected such that, when they are converted in a molar ratio of 1.0:1.0, the overall enthalpy of reaction over all process stages is from −900 kJ/kg to −500 kJ/kg as determined according to DIN 51007:1994-06.

2. The continuous solvent-free multistage process as claimed in claim 1, wherein a portion of the overall enthalpy of reaction formed in at least one process stage is removed.

3. The continuous solvent-free multistage process as claimed in claim 1, wherein the overall enthalpy of reaction over all process stages is in the range from −900 kJ/kg to −550 kJ/kg.

4. The continuous solvent-free multistage process as claimed in claim 1, wherein there is an overall molar ratio of component A to component B of 1.0:0.95 to 0.95:1.0.

5. The continuous solvent-free multistage process as claimed in claim 1, wherein the at least one hydroxy-terminated prepolymer is formed in at least one process stage from the total amount of component A and a first portion of component B.

6. The continuous solvent-free multistage process as claimed in claim 1, wherein the at least one hydroxy-terminated prepolymer is formed in at least one process stage from a first portion of component A and a first portion of component B, where the molar ratio of the portions of component B to component A used is from 0.65:1.0 to 0.98:1.0, based on the total molar amount of component A used in the process.

7. The continuous solvent-free multistage process as claimed in claim 1, wherein the at least one hydroxy-terminated prepolymer is reacted with a further portion of component B to give the thermoplastic polyurethane in at least one further process stage that follows the formation of the at least one hydroxy-terminated prepolymer.

8. The continuous solvent-free multistage process as claimed in claim 1, wherein the at least one hydroxy-terminated prepolymer is formed in at least one process stage from a first portion of component A and a first portion of component B, wherein the at least one hydroxy-terminated prepolymer is reacted with at least one NCO-terminated prepolymer to give the thermoplastic polyurethane in at least one further process stage that follows the formation of the hydroxy-terminated prepolymer, and wherein the at least one NCO-terminated prepolymer is formed in at least one further process stage from a second portion of component A and a second portion of component B.

9. The continuous solvent-free multistage process as claimed in claim 1, wherein one or more aliphatic or cycloaliphatic diisocyanates are used as component B.

10. The continuous solvent-free multistage process as claimed in claim 1, wherein one or more aliphatic diisocyanates are used as component B.

11. The continuous solvent-free multistage process as claimed in claim 1, wherein from 90 mol % to 100 mol % of the one or more diols of component A have a molecular weight of 62 g/mol to 250 g/mol.

12. The continuous solvent-free multistage process as claimed in claim 1, wherein one or more aliphatic, cycloaliphatic and/or araliphatic diols are used as component A.

13. The continuous solvent-free multistage process as claimed in claim 1, wherein the at least one hydroxy-terminated prepolymer is formed by polyaddition of at least one combination of component A and component B selected from the group consisting of 1,4-diisocyanatobutane with ethane-1,2-diol, 1,4-diisocyanatobutane with propane-1,2- and/or -1,3-diol, 1,4-diisocyanatobutane with butane-1,2-, -1,3- and/or -1,4-diol, 1,4-diisocyanatobutane with pentane-1,5-diol, 1,4-diisocyanatobutane with hexane-1,6-diol, 1,4-diisocyanatobutane with heptane-1,7-diol, 1,4-diisocyanatobutane with octane-1,8-diol, 1,4-diisocyanatobutane with nonane-1,9-diol, 1,4-diisocyanatobutane with decane-1,10-diol, 1,4-diisocyanatobutane with cyclobutane-1,3-diol, 1,4-diisocyanatobutane with cyclopentane-1,3-diol, 1,4-diisocyanatobutane with cyclohexane-1,2-, -1,3- and -1,4-diol and/or mixtures of at least 2 isomers, 1,4-diisocyanatobutane with cyclohexane-1,4-dimethanol, 1,5-diisocyanatopentane with ethane-1,2-diol, 1,5-diisocyanatopentane with propane-1,2- and/or -1,3-diol, 1,5-diisocyanatopentane with butane-1,2-, -1,3- and/or -1,4-diol, 1,5-diisocyanatopentane with pentane-1,5-diol, 1,5-diisocyanatopentane with hexane-1,6-diol, 1,5-diisocyanatopentane with heptane-1,7-diol, 1,5-diisocyanatopentane with octane-1,8-diol, 1,5-diisocyanatopentane with cyclobutane-1,3-diol, 1,5-diisocyanatopentane with cyclopentane-1,3-diol, 1,5-diisocyanatopentane with cyclohexane-1,2-, -1,3- and -1,4-diol and/or mixtures of at least 2 isomers, 1,5-diisocyanatopentane with cyclohexane-1,4-dimethanol, 1,6-diisocyanatohexane with ethane-1,2-diol, 1,6-diisocyanatohexane with propane-1,2- and/or -1,3-diol, 1,6-diisocyanatohexane with butane-1,2-, -1,3- and/or -1,4-diol, 1,6-diisocyanatohexane with pentane-1,5-diol, 1,6-diisocyanatohexane with hexane-1,6-diol, 1,6-diisocyanatohexane with heptane-1,7-diol, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane with ethane-1,2-diol and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane with propane-1,2- and/or -1,3-diol.

14. The continuous solvent-free multistage process as claimed in claim 1, wherein an average residence time over all process stages is between 10 seconds and 110 minutes.

15. The continuous solvent-free multistage process as claimed in claim 1, wherein the multistage process achieves a total throughput of polyurethane polymer of at least 0.5 kg/h.

16. The continuous solvent-free multistage process as claimed in claim 1, wherein the process comprises: i) continuously mixing the total amount or the first portion of component A with the first portion of component B and optionally components C and/or D, ii) continuously reacting the reaction mixture from step i) in at least one first process stage to form the at least one hydroxy-terminated prepolymer, wherein a temperature of the reaction mixture in the at least one first process stage is kept below a breakdown temperature of the at least one hydroxy-terminated prepolymer, iii) continuously transferring the at least one hydroxy-terminated prepolymer formed in step ii) into a second process stage, wherein the second process stage is connected to the first process stage by at least one mass transfer conduit, iv) optionally continuously mixing and reacting the remaining portions of components A and B in a third process stage to prepare at least one NCO-terminated prepolymer, wherein a temperature of the reaction mixture in the third process stage is kept below a breakdown temperature of the at least one NCO-terminated prepolymer, wherein the third process stage is connected to the first and/or second process stage via at least one mass transfer conduit, v) continuously mixing the at least one hydroxy-terminated prepolymer with the remaining portion of component B and optionally with the remaining portion of component A and/or the at least one NCO-terminated prepolymer from step iv), vi) continuously reacting the mixture from step v) to obtain the thermoplastic polyurethane, wherein a temperature of the reaction mixture in the process stage is kept below a breakdown temperature of the thermoplastic polyurethane, vii) continuously cooling and pelletizing the thermoplastic polyurethane.

17. A thermoplastic polyurethane obtained from the continuous solvent-free multistage process as claimed in claim 1.

18. The continuous solvent-free multistage process as claimed in claim 9, wherein the one or more aliphatic or cycloaliphatic diisocyanates used as component B are selected from the group consisting of 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,4-diisocyanato-3,3,5-trimethylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, 1,3-diisocyanato-4-methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate; IPDI) and/or mixtures of at least 2 of these.

19. The continuous solvent-free multistage process as claimed in claim 12, wherein the one or more aliphatic, cycloaliphatic and/or araliphatic diols used as component A are selected from the group consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, heptane-1,7-diol, octane-1,8-diol, nonane-1,9-diol, cyclobutane-1,3-diol, cyclopentane-1,3-diol, cyclohexane-1,2-, -1,3- and -1,4-diol, cyclohexane-1,4-dimethanol, and/or mixtures of at least 2 of these.

Description

[0175] The figures and examples elucidated hereinafter serve to further elucidate the invention, but these merely constitute illustrative examples of particular embodiments, and not a restriction of the scope of the invention. The individual figures show:

[0176] FIG. 1: Preferred embodiment of a construction for performance of a two-stage continuous preparation of a thermoplastic polyurethane according to the invention, by reaction sequence in a temperature-controlled polymerization reactor and extruder.

[0177] FIG. 2: Preferred embodiment of a construction for performance of a two-stage continuous preparation of a thermoplastic polyurethane according to the invention, by reaction sequence in a loop reactor and extruder.

EXAMPLES

[0178] All percentages are based on weight, unless stated otherwise.

[0179] Raw materials used:

[0180] Hexamethylene 1,6-diisocyanate (HDI), pentamethylene 1,5-diisocyanate (PDI), isophorone diisocyanate (IPDI), 4,4′-diisocyanatodicyclohexylmethane (H12MDI) and xylylene diisocyanate (XDI) were sourced from Covestro AG.

[0181] Butane-1,4-diol (BDO) was sourced from Ashland. Propane-1,3-diol (PDO), hexane-1,6-diol (HDO) and cyclohexane-1,4-dimethanol were sourced from Sigma-Aldrich. The purity of each of the raw materials was ≥99%.

[0182] Colour Values

[0183] Colour values in the CIE-Lab colour space were determined with a Konica Minolta CMS spectrophotometer with the D 65 illuminant, 10° observer, according to DIN EN ISO 11664-1 (July 2011).

[0184] Differential Scanning Calorimetry (DSC)

[0185] Melting point was determined by means of DSC (differential scanning calorimetry) with a Mettler DSC 12E (Mettler Toledo GmbH, Giessen, Germany) in accordance with DIN EN 61006 (November 2004). Calibration was effected via the melt onset temperature of indium and lead. 10 mg of substance were weighed out in standard capsules. The measurement was effected by three heating runs from −50° C. to +200° C. at a heating rate of 20 K/min with subsequent cooling at a cooling rate of 20 K/min. Cooling was effected by means of liquid nitrogen. The purge gas used was nitrogen. The values reported are each based on the evaluation of the 2nd heating curve.

[0186] Screening by Differential Thermal Analysis (DTA)

[0187] The enthalpy data were ascertained by means of a screening DTA and conducted in an ISO 17025 accredited laboratory. The samples were weighed out in glass ampoules, sealed gas-tight and heated in the measuring instrument from −50° C. to +450° C. at 3 K/min. By means of thermocouples, the differential between the sample temperature and the temperature of an inert reference (aluminium oxide) was determined. The starting weight was 20 mg-30 mg. All measurements were conducted to DIN 51007 (June 1994). The measurement error of the instrument is ±2%.

TABLE-US-00001 TABLE 1 Enthalpies of reaction determined experimentally by DTA. The molar ratio of diisocyanate component to diol component in the determinations is 1.0:1.0. Diisocyanate Diol Energy [kJ/kg] Inventive examples hexamethylene 1,6-diisocyanate butane-1,4-diol −690 hexamethylene 1,6-diisocyanate hexane-1,6-diol −550 hexamethylene 1,6-diisocyanate: butane-1,4-diol −595 l,4-bis(isocyanatomethyl)benzene 80:20 hexamethylene 1,6-diisocyanate: butane-1,4-diol −575 isophorone diisocyanate 80:20 pentamethylene 1,5-diisocyanate 1,4-butanediol: −665 cyclohexane-1,4- dimethanol 70:30 Comparative example diphenylmethane butane-1,4-diol −465 4,4′-diisocyanate

Comparative Example 1

[0188] In housing 1 of a twin-shaft extruder (ZSK 53 from Werner&Pfleiserer), 64.4 kg/h of hexamethylene 1,6-diisocyanate, heated to 105° C., and a mixture of 22.8 kg/h of a poly-THF diol (1000 g/mol, from BASF) with 32.9 kg/h of butane-1,4-diol, heated to 110° C., were metered in. The extruder speed was 270 rpm. The residence time in the extruder was about 42 seconds. At the extruder outlet, the melt was filtered through a single-ply metal sieve with a mesh size of 200 micrometres, drawn off as a strand, cooled in a water bath and pelletized.

[0189] In spite of maximum cooling, the temperature in the extruder in 7 of 12 housings rose to values above 240° C. The product obtained had yellowish discolouration as a result of the significant heating and had dark brown to black specks and was thus commercially unusable.

Comparative Example 2

[0190] A nitrogen-inertized 5 l pressure tank with an anchor stirrer, base outlet and internal thermometer was initially charged with butane-1,4-diol (1.35 kg) under nitrogen (1 bar), which was stirred until an internal temperature of 90° C. was attained. Over a period of 2 h, the total amount of hexamethylene 1,6-diisocyanate was then metered continuously into the pressure tank (2.5 kg), while the reactor temperature was simultaneously increased continuously up to 190° C. Owing to the heat of reaction released in the polyaddition, the temperature of the reaction mixture over the entire reaction time was up to 15° C. above the respective defined reactor temperature. After the addition of hexamethylene 1,6-diisocyanate had ended, the mixture was stirred at 200° C. for a further 10 minutes. During this time, a rise in the viscosity to 106 Pa*s (frequency of 1 Hz, rheometer: Anton Paar MCR-302; measurement to ISO 6721-10 (September 2015)) was detected. This rise in viscosity led to failure of the stirrer. Owing to the high viscosity, discharge of the polymer from the pressure tank was not possible.

[0191] The melting point of the polymer is 174.9° C. (DSC 2nd heating after cooling at 20 K/min).

Comparative Example 3 (EP 0 135 111 A2)

[0192] EP 0 135 111 A2 discloses the preparation of thermoplastic polyurethanes by reaction of a polyester polyol, MDI, NDI, and butane-1,4-diol, hexane-1,6-diol and trimethylolpropane. A mixture of 3.72% by mass of 4,4′-MDI (x.sub.MDI=0.0372) and 23.13% by mass of 1,5-NDI (x.sub.NDI=0.2313) is reacted with different OH-terminated components. Complete conversion is assumed. 4,4′-MDI has a molecular mass of M.sub.m,MDI=250.25 g/mol, and 1,5-NDI a molecular mass of M.sub.m,NDI=210.19 g/mol.

[0193] The molar concentration of 4,4′-MDI is thus

[00003]$c_{\mathrm{MDI}}=\frac{x_{\mathrm{MDI}}}{M_{m,\mathrm{MDI}}}=0.1487\frac{\mathrm{mol}}{\mathrm{kg}},$

and the molar concentration of 1,5-NDI is

[00004]$c_{\mathrm{NDI}}=\frac{x_{\mathrm{NDI}}}{M_{m,\mathrm{NDI}}}=1.1004\frac{\mathrm{mol}}{\mathrm{kg}}.$

Since the molecules of 4,4′-MDI and 1,5-NDI each have two isocyanate groups, the concentration of the isocyanate end groups is

[00005]$c_{\mathrm{NCO}}=2.Math.\left(c_{\mathrm{NDI}}+c_{\mathrm{MDI}}\right)=2.4982\frac{\mathrm{mol}}{\mathrm{kg}}\approx 2.5\frac{\mathrm{mol}}{\mathrm{kg}}.$

[0194] The molar enthalpy of reaction of the urethane per mole of isocyanate is about

[00006]$\Delta h_{m,\mathrm{NCO}}=-85\frac{\mathrm{kJ}}{\mathrm{mol}}.$

Thus, the mass-based enthalpy of reaction is

[00007]$\Delta h={\Delta h}_{m,\mathrm{NCO}}.Math.c_{\mathrm{NCO}}~-212\frac{\mathrm{kJ}}{\mathrm{kg}}$

and hence is not within the inventive range.

Comparative Example 4 (EP 0 900812A1, Examples 1-4)

[0195] EP 0 900812A1 discloses the preparation of thermoplastic polyurethanes by reaction of a polyester polyol or polyether polyol, MDI, and butane-1,4-diol and in some cases also hexane-1,6-diol. In examples 1-4, n.sub.PBA=1.0 mol of polybutane-1,4-diol adipate (molecular mass reported as M.sub.m,PBA=2200 g/mol), mass m.sub.PBA=n.sub.PBA.Math.M.sub.m,PBA=2.2 kg

[0196] n.sub.BDO=2.5 mol of butane-1,4-diol (molecular mass M.sub.m,PBA=90.12 g/mol), mass m.sub.BDO=n.sub.BDO.Math.M.sub.m,BDO=0.225 kg and

[0197] 3.5 mol of 4,4′-MDI (molecular mass M.sub.m,MDI=250.25 g/mol), mass m.sub.MDI=n.sub.MDI.Math.M.sub.mMDI=0.876 kg are used. The total mass of the reactive components is thus m.sub.r=m.sub.PBA+m.sub.BDO+m.sub.MDI=3.301 kg.

[0198] In addition, a proportion by mass of X.sub.gsA=0.007 of bisethylenestearylamide, based on the total mass, was used. The total mass is thus

[00008]$m_{ges}=\frac{m_r}{1-x_{\mathrm{BSA}}}=3.324\mathrm{kg}.$

[0199] The molar concentration of 4,4′-MDI is

[00009]$c_{\mathrm{MDI}}=\frac{n_{\mathrm{MDI}}}{m_{\mathrm{ges}}}=1.05\frac{\mathrm{mol}}{\mathrm{kg}}$

[0200] Since one molecule of 4,4′-MDI has two isocyanate groups, the concentration of isocyanate end groups is

[00010]$c_{\mathrm{NCO}}=2c_{\mathrm{MDI}}=2.1\frac{\mathrm{mol}}{\mathrm{kg}}.$

[0201] BSA The molar enthalpy of reaction of urethane reaction per mole of isocyanate is about

[00011]${\Delta h}_{m,\mathrm{NCO}}=-85\frac{\mathrm{kJ}}{\mathrm{mol}}.$

Thus, the mass-based enthalpy of reaction is

[00012]$\Delta h=\Delta h_{m,\mathrm{NCO}}.Math.c_{\mathrm{NCO}}=-179\frac{\mathrm{kJ}}{\mathrm{kg}}$

and is thus not within the inventive range.

Comparative Example 5 (EP 0 900812A1, Examples 5-6)

[0202] In examples 5 and 6 of EP 0 900812A1, n.sub.PPEG=0.4 mol of polypropylene ether glycol having a molecular mass of M.sub.m,PPEG=2000 g/mol, i.e. a mass of m.sub.PPEG=n.sub.PPEG.Math.M.sub.M,PPEG=800 g, n.sub.PMEG=0.6 mol of polytetramethylene ether glycol having a molecular mass of M.sub.m,PMEG=1000 g/mol, i.e. a mass of m.sub.PMEG=n.sub.PMEG.Math.M.sub.m,PMEG=600 g, n.sub.BDO=1.84 mol of butane-1,4-diol having a molecular mass of M.sub.m,BDO=90.12 g/mol, i.e. a mass of m.sub.BDO=n.sub.BDO M.sub.m,BDO=165.82 g, n.sub.HDO=0.08 mol of hexane-1,6-diol having a molecular mass of M.sub.m,HDO=118.18 g/mol, i.e. a mass of m.sub.HDO=n.sub.HDO.Math.M.sub.M,HDO=9.45 g, and n.sub.PPEG=2.92 mol of 4,4′-MDI having a molecular mass of M.sub.m,MDI=250.25 g/mol, i.e. a mass of m.sub.MDI=n.sub.MDI.Math.M.sub.m,MDI=730.73 g, were used.

[0203] The total mass of the reactive components was thus nt, =m.sub.PPEG m.sub.PMEG M.sub.BDO M.sub.HDO+m.sub.MDI=2306 g.

[0204] In addition, a proportion by mass of X.sub.BSA=0.007 of bisethylenestearylamide, based on the total mass, was used. The total mass is thus

[00013]$m_{\mathrm{ges}}=\frac{m_r}{1-x_{\mathrm{BSA}}}=2322g.$

[0205] The concentration of NDI is

[00014]$c_{\mathrm{MDI}}=\frac{n_{\mathrm{MDI}}}{m_{\mathrm{ges}}}=1.257\frac{\mathrm{mol}}{\mathrm{kg}}.$

Since one molecule of 4,4′-MDI has two isocyanate groups, the concentration of isocyanate end groups

[00015]$c_{\mathrm{NCO}}=2c_{\mathrm{MDI}}=2.515\frac{\mathrm{mol}}{\mathrm{kg}}.$

[0206] The molar enthalpy of reaction of the urethane reaction per mole of isocyanate is about

[00016]$\Delta h_{m,\mathrm{NCO}}=-85\frac{\mathrm{kJ}}{\mathrm{mol}}.$

thus, the mass-based enthalpy of reaction is

[00017]$\Delta h=\Delta h_{m,\mathrm{NCO}}.Math.c_{\mathrm{NCO}}=-214\frac{\mathrm{kJ}}{\mathrm{kg}}$

thus not within the inventive range.

Inventive Example 1 (FIG. 1)

[0207] FIG. 1 shows a schematic of the construction for performance of the two-stage continuous preparation of a thermoplastic polyurethane.

[0208] From reservoir 1, 311.7 g/h of hexamethylene 1,6-diisocyanate were conveyed into the mixer 100 with the pump 100 (model: SyrDos2 with 10 ml syringes from HiTec Zang). At the same time, from reservoir 2, 208.7 g/h of butane-1,4-diol were likewise conveyed into the mixer 100 with the pump 200 (model: SyrDos2 with 10 ml syringes from HiTec Zang). At room temperature, the two streams of matter were mixed in the mixer 100. The mixer used was a cascade mixer from Ehrfeld Microtechnik BTS GmbH which was heated by a heating band to a temperature of 200° C. At the outlet of the mixer, the mixture had a temperature of 100° C. The mixture was subsequently guided into the reactor 100 that had been heated to 170° C. (model: CSE-X/8G, Form G, internal diameter=12.3 mm, length=500 mm from Fluitec, heat exchange capacity of 60 kilowatts per cubic metre and Kelvin). The residence time in the reactor was 5 min. The prepolymer continuously exiting from reactor 100 was transferred through a pipeline heated to 200° C. into the second housing of a 2-shaft extruder (Miniextruder Process 11/Thermo Fisher). The extruder was heated to 200° C. over its entire length, and the speed of the shafts was 100 rpm. Subsequently, 70.1 g/h of hexamethylene 1,6-diisocyanate were conveyed into housing 3 of the extruder with the pump 300 (model: SyrDos2 with 10 ml syringes from HiTec Zang). The resultant milky-white product was discharged through the extruder nozzles, drawn off as a strand, cooled in a water bath (25° C.) and pelletized.

[0209] The average residence time over all process stages was about 6 minutes.

[0210] The temperature of the heating medium at the entrance to the reactor 100 was 170° C. The product temperature at the exit of the reactor 100 was 172° C. 71% of the overall enthalpy of reaction was thus removed in reactor 100.

[0211] The melting point of the polymer prepared is 182.9° C. (DSC 2nd heating after cooling at 20 K/min). The L* value is 82.7; the b* value is 0.2.

Inventive Example 2

[0212] In an experimental setup as described in Example 1, 311.7 g/h of hexamethylene 1,6-diisocyanate were metered in with pump 100, 273.7 g/h of hexane-1,6-diol with pump 200, and 70.1 g/h of hexamethylene 1,6-diisocyanate with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 50° C. The heating medium temperature of the reactor 100 was 170° C. The temperature at the outlet was 176° C. 61% of the overall enthalpy of reaction was thus removed in the reactor 100.

[0213] The average residence time over all process stages was about 6 minutes. The melting point of the polymer prepared is 168.6° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 3

[0214] In an experimental setup as described in Example 1, 311.7 g/h of hexamethylene 1,6-diisocyanate were metered in with pump 100, 240.2 g/h of pentane-1,5-diol with pump 200, and 73.9 g/h of hexamethylene 1,6-diisocyanate with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 100° C. The heating medium temperature of the reactor 100 was 155° C. The temperature at the outlet was 160° C. 70% of the overall enthalpy of reaction was thus removed in the reactor 100.

[0215] The average residence time over all process stages was about 6 minutes. The melting point of the polymer prepared is 152.7° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 4

[0216] In an experimental setup as described in Example 1, 311.7 g/h of hexamethylene 1,6-diisocyanate were metered in with pump 100, 176.1 g/h of propane-1,3-diol with pump 200, and 73.9 g/h of hexamethylene 1,6-diisocyanate with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 162° C. The heating medium temperature of the reactor 100 was 165° C.; the temperature at the outlet was 168° C. 76% of the enthalpy of reaction was thus removed in the reactor 100.

[0217] The average residence time over all process stages was about 7 minutes. The melting point of the polymer prepared is 161.8° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 5

[0218] In an experimental setup as described in Example 1, 285.7 g/h of pentamethylene 1,5-diisocyanate were metered in with pump 100, 176.2 g/h of propane-1,3-diol with pump 200, and 64.3 g/h of pentamethylene 1,5-diisocyanate with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 130° C. The heating medium temperature of the reactor 100 was 150° C.; the temperature at the outlet was 152° C. 78% of the enthalpy of reaction was thus removed in the reactor 100.

[0219] The average residence time over all process stages was about 7 minutes. The melting point of the polymer prepared is 153.3° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 6

[0220] In an experimental setup as described in Example 1, 285.7 g/h of pentamethylene 1,5-diisocyanate were metered in with pump 100, 208.7 g/h of butane-1,4-diol with pump 200, and 67.8 g/h of pentamethylene 1,5-diisocyanate with pump 300, and were reacted.

[0221] The temperature at the inlet to the reactor 100 was 30° C. The heating medium temperature of the reactor 100 was 176° C.; the temperature at the outlet was 180° C. 78% of the enthalpy of reaction was thus removed in the reactor 100. 61% of the enthalpy of reaction was thus removed in the reactor 100.

[0222] The average residence time over all process stages was about 7 minutes. The melting point of the polymer prepared is 160.9° C. (DSC 2nd heating after cooling at 20 K/min). The L* value is 81.5; the b* value is 0.7.

Inventive Example 7

[0223] In an experimental setup as described in Example 1, 311.7 g/h of hexamethylene 1,6-diisocyanate were metered in with pump 100, 192.5 g/h of a mixture of butane-1,4-diol and propane-1,3-diol (molar amount 1:1) with pump 200, and 70.1 g/h of hexamethylene 1,6-diisocyanate with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 90° C. The heating medium temperature of the reactor 100 was 135° C.; the temperature at the outlet was 140° C. 75% of the enthalpy of reaction was thus removed in the reactor 100.

[0224] The average residence time over all process stages was about 7 minutes. The melting point of the polymer prepared is 137.0° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 8

[0225] In an experimental setup as described in Example 1, 305.5 g/h of pentamethylene 1,5-diisocyanate were metered in with pump 100, 259.1 g/h of a mixture of butane-1,4-diol and cyclohexane-1,4-dimethanol (molar amount 7:3) with pump 200, and 68.4 g/h of pentamethylene 1,5-diisocyanate with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 60° C. The heating medium temperature of the reactor 100 was 175° C.; the temperature at the outlet was 180° C. 64% of the enthalpy of reaction was thus removed in the reactor 100.

[0226] The average residence time over all process stages was about 6 minutes. The melting point of the polymer prepared is 166.1° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 9

[0227] In an experimental setup as described in Example 1, 310.0 g/h of a mixture of hexamethylene 1,6-diisocyanate and m-xylylene diisocyanate (molar amount 8:2) were metered in with pump 100, 208.1 g/h of butane-1,4-diol with pump 200, and 83.9 g/h of a mixture of hexamethylene 1,6-diisocyanate and m-xylylene diisocyanate (molar amount 8:2) with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 40° C. The heating medium temperature of the reactor 100 was 176° C.; the temperature at the outlet was 180° C. 61% of the enthalpy of reaction was thus removed in the reactor 100.

[0228] The average residence time over all process stages was about 7 minutes. The melting point of the polymer prepared is 163.6° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 10

[0229] In an experimental setup as described in Example 1, 313.3 g/h of a mixture of hexamethylene 1,6-diisocyanate and isophorone diisocyanate (molar amount 8:2) were metered in with pump 100, 208.1 g/h of butane-1,4-diol with pump 200, and 96.1 g/h of a mixture of hexamethylene 1,6-diisocyanate and isophorone diisocyanate (molar amount 8:2) with pump 300, and were reacted. The temperature at the inlet to the reactor 100 was 40° C. The heating medium temperature of the reactor 100 was 174° C.; the temperature at the outlet was 180° C. 61% of the enthalpy of reaction was thus removed in the reactor 100.

[0230] The average residence time over all process stages was about 6 minutes. The melting point of the polymer prepared is 163.7° C. (DSC 2nd heating after cooling at 20 K/min).

Inventive Example 11 (FIG. 2)

[0231] From a 250 litre reservoir for hexamethylene 1,6-diisocyanate 1, with the aid of a toothed ring pump 2 (from HNP, MZR 7255), a hexamethylene 1,6-diisocyanate stream A was conveyed to a static mixer 7. The throughput of the hexamethylene 1,6-diisocyanate stream A was measured by means of a mass flow meter 3 (from Bronkhorst, Mini Cori-Flow M1X, max. flow rate 12 kg/h) and adjusted to a value of 2.911 kg/h. From a 250 litre reservoir for butane-1,4-diol 4, with the aid of a toothed ring pump 5 (from HNP, MZR 7205), a butane-1,4-diol stream B was conveyed to the static mixer 7. The throughput of the butane-1,4-diol stream was measured by means of a mass flow meter 6 (from Bronkhorst, Mini Con-Flow M1X, max. flow rate 8 kg/h) and adjusted to a value of 2.000 kg/h. The temperature of the hexamethylene 1,6-diisocyanate was ambient temperature, about 25° C. The temperature of the butane-1,4-diol was 40° C. In the static mixer 7 (Sulzer SMX, diameter 6 mm, ratio of length to diameter L/D=10), the hexamethylene 1,6-diisocyanate stream A and the butane-1,4-diol stream B were mixed with one another. This is stream C.

[0232] The mixed and dispersed stream C was mixed in a circulation system with a circulating polymer stream D in a static mixer 8 (static mixer equivalent to Sulzer SMX, internal diameter 34 mm, L/D=20) to give a stream H. The temperature of stream D was 182° C.

[0233] The mixed and already partly reacted stream H was guided into a temperature-controllable static mixer 9. The reaction proceeds there for the most part, and the heat of reaction that arose was removed. The temperature-controllable static mixer 9 was of similar construction to a Sulzer SMX reactor with internal crossed tubes. It had an internal volume of 1.9 litres and a heat exchange area of 0.44 square metres. It was heated/cooled with heat carrier oil. The heating medium temperature at the inlet was 180° C.

[0234] The product stream left the temperature-controllable static mixer 9 as a largely reacted stream E with a temperature of 183° C. At a branch 11, stream E was split into two substreams F and G. The pressure of substream F was increased at a gear pump 10. Substream F became the abovementioned substream D downstream of the pump.

[0235] The gear pump 10 (from Witte Chem 25,6-3) had a volume per cycle of 25.6 cubic centimetres and a speed of 50 per minute.

[0236] The whole circulation system was full, and the polymer was largely incompressible. Therefore, the mass flow rate of stream G was identical to that of stream C. Stream G consisted of oligomer.

[0237] The whole circulation system consisted of jacketed pipelines and apparatuses that were heated with thermal oil. The heating medium temperature was 182° C.

[0238] Downstream of the pressure-retaining valve 12, stream G was run past a three-way valve 13. On startup and shutdown or in the event of faults, it was possible to run said stream G to a waste vessel 14, an open 200 litre metal vat with air extraction. In regular operation, stream G was guided to an extruder 18.

[0239] From the hexamethylene 1,6-diisocyanate reservoir 1, with the aid of a micro toothed ring pump 15 (MZR 6355 from HNP), a hexamethylene 1,6-diisocyanate stream J was withdrawn. The throughput of the hexamethylene 1,6-diisocyanate stream J was measured by means of a mass flow meter 16 (from Bronkhorst, Mini Cori-Flow M1X, maximum flow rate 2 kg/h) and adjusted to 0.784 kilogram per hour. The temperature of the hexamethylene 1,6-diisocyanate stream J was likewise room temperature, about 25° C. This stream was likewise guided to the extruder 18.

[0240] The extruder 18 was a ZSK 26 MC from Coperion, which was operated at temperatures of 200° C. and a speed of 66 revolutions per minute. In this extruder, stream G, by means of a venting system 17 that was operated at a reduced pressure of about 1 mbar relative to ambient pressure, was freed of any inert gases entrained with streams of matter A and B and of possible volatile reaction products. Downstream of the addition of the oligomer stream G, the hexamethylene 1,6-diisocyanate stream J was added and the reaction to give the polymer was conducted. Before the end of the extruder, the resulting polymer stream was freed of volatile constituents via a degassing operation 19. The pressure in this degassing was 200 mbar below ambient pressure. The polymer stream K was expressed through two nozzles, cooled in a water bath filled with demineralized water, and chopped into pellets by means of a pelletizer 21.

[0241] The average residence time over all process stages was 51 minutes. The melting point of the polymer is 185.2° C. (DSC 2nd heating after cooling at 20 K/min).

[0242] 58% of the overall enthalpy of reaction was removed in the temperature-controllable static mixer 9.

Inventive Example 12 (FIG. 2)

[0243] In an experimental setup as described in Example 11, on this occasion, 2.711 kg/h of pentamethylene 1,5-diisocyanate (stream A) were conveyed into the static mixer 7 from reservoir 1, and 2.000 kg/h of butane-1,4-diol (stream B) from reservoir 4. The throughput of the pentamethylene 1,5-diisocyanate stream J was adjusted to 0.677 kilogram per hour.

[0244] The temperatures of the raw materials and the temperatures of the other streams of matter and of the plant components and heating media corresponded to those as described in Example 11. The extruder speed and the degassing pressures also corresponded to those in Example 11. The heating temperatures were 165° C.

[0245] The average residence time over all process stages was 53 minutes. The melting point of the polymer prepared is 159.0° C. (DSC 2nd heating after cooling at 20 K/min). 62% of the overall enthalpy of reaction was removed in the temperature-controllable static mixer 9.