Functionalized polyoxymethylene block copolymers

Abstract

The invention relates to a method for producing functionalized polyoxymethylene block copolymers comprising the step of polymerizing formaldehyde in a reaction vessel in the presence of a catalyst, the polymerization of formaldehyde in addition taking place in the presence of a starter compound comprising at least 2 Zerewitinoff active H atoms, to obtain an intermediate product. The intermediate product obtained is subsequently reacted with a cyclic carboxylic acid ester or carbonic acid ester, thus obtaining a functionalized polyoxymethylene block copolymer. The invention further relates to functionalized polyoxymethylene block copolymers obtained by such a method and to the use of said copolymers.

Claims

1. A process for preparing functionalized polyoxymethylene block copolymers, comprising the step of polymerizing formaldehyde in a reaction vessel in the presence of a catalyst, wherein the polymerization of formaldehyde is effected in the presence of a starter compound having at least 2 Zerewitinoff-active hydrogen atoms, and wherein the polymerizing step produces an intermediate having a number-average molecular weight of <4500 g/mol, and the intermediate is reacted with a cyclic carboxylic or carbonic ester, giving a functionalized polyoxymethylene block copolymer.

2. The process as claimed in claim 1, wherein the catalyst is selected from the group consisting of basic catalysts, Lewis-acidic catalysts, and combinations thereof.

3. The process as claimed in claim 1, wherein the reaction of the intermediate with the cyclic carboxylic or carbonic ester is conducted in the presence of a catalyst which is the same catalyst as in the preceding polymerization of formaldehyde.

4. The process as claimed in claim 1, wherein the starter compound has a number-average molecular weight of 62 g/mol to 4470 g/mol.

5. The process as claimed in claim 4, wherein the starter compound has a number-average molecular weight of 100 g/mol to 3000 g/mol.

6. The process as claimed in claim 1, wherein the starter compound is selected from the group consisting of polyether polyols, polyester polyols, polyether ester polyols, polycarbonate polyols, polyacrylate polyols, and combinations thereof.

7. The process as claimed in claim 1, wherein the cyclic carboxylic or carbonic ester is selected from the group consisting of aliphatic lactones, aromatic lactones, lactides, cyclic carbonates, cyclic anhydrides, and combinations thereof.

8. The process as claimed in claim 1, wherein the formaldehyde is introduced into the reaction vessel as gaseous formaldehyde.

9. The process as claimed in claim 1, wherein the polymerization is effected in the presence of a comonomer.

10. A functionalized polyoxymethylene block copolymer prepared by a process as claimed in claim 1.

11. A functionalized polyoxymethylene block copolymer as claimed in claim 10 having a number-average molecular weight of 12 000 g/mol.

12. A functionalized polyoxymethylene block copolymer as claimed in claim 10 having a viscosity at 20 C. of 100 000 mPa s.

13. A composition comprising the functionalized polyoxymethylene block copolymer as claimed in claim 10, wherein the composition is selected from the group consisting of polyamides, polyurethanes, washing and cleaning composition formulations, drilling fluids, fuel additives, ionic and nonionic surfactants, lubricants, process chemicals for papermaking or textile production, and cosmetic formulations.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 a reactor arrangement for performance of the process of the invention

(2) H-Functional Oligomeric Compounds Used:

(3) PET-1: bifunctional poly(oxyethylene)polyol having the nominal molecular weight M.W.=600 g/mol and the average empirical formula HO(CH.sub.2CH.sub.2O)).sub.13.23H. An OH number of 187.15 mg.sub.KOH/g, a number-average molecular weight M.sub.n=658 g/mol and a polydispersity index PDI=1.087 (measured by GPC in chloroform against polypropylene glycol standards) were measured.

(4) Isocyanates Used:

(5) Isocyanate 1 having an average functionality of 2.6 and an NCO value of 31.1-31.1%, containing 42.4% 4,4-MDI, 12.6% 2,4-MDI, 2.2% 2.2-MDI (Desmodur VP PU 0325 from Bayer).

(6) The formaldehyde source used was trioxane (CAS [110-88-3]) from Aldrich (catalog number T81108).

(7) Description of the Methods:

(8) The molar mass distributions were determined by means of gel permeation chromatography (GPC).

(9) Gel permeation chromatography (GPC): The measurements were effected on the Agilent 1200 Series instrument (G1310A Iso Pump, G1329A ALS, G1316A TCC, G1362A RID, G1365D MWD), detection via RID; eluent: chloroform (GPC grade), flow rate 1.0 ml/min; column combination: PSS SDV precolumn 850 mm (5 m), 2PSS SDV linear S 8300 mL (5 m). Polypropylene glycol samples of known molar mass from PSS Polymer Standards Service were used for calibration. The measurement recording and evaluation software used was the software package PSS WinGPC Unity. The GPC chromatograms were recorded in accordance with DIN 55672-1, except using chloroform as eluent rather than THF.

(10) .sup.1H NMR spectroscopy: The measurements were effected on the Bruker AV400 instrument (400 MHz); the chemical shifts were calibrated relative to the solvent signal (CDCl.sub.3, =7.26 ppm); s=singlet, m=multiplet, bs=broadened singlet, kb=complex region. The integrals were reported relative to one another.

(11) .sup.13C NMR spectroscopy: The measurements were effected on the Bruker AV400 instrument (100 MHz); the chemical shifts were calibrated relative to the solvent signal (CDCl.sub.3, =77.16 ppm); APT (attached proton test): CH.sub.2, C.sub.quart: positive signal (+); CH, CH.sub.3: negative signal (); HMBC: Hetero multiple bond correlation; HSQC: Heteronuclear single-quantum correlation.

(12) Infrared (IR) spectroscopy: The measurements were effected on the Bruker Alpha-P FT-IR spectrometer; the measurements were effected neat; signal intensities: vs=very strong, s=strong, m=medium, w=weak, vw=very weak; b=broadened band.

(13) Electrospray mass spectrometry (ESI-MS): The measurements were effected on the Thermo Fisher Scientific LTQ Orbitrap XL instrument; samples were diluted with MeOH.

(14) The OH number (hydroxyl number) was determined on the basis of DIN 53240-2, except using N-methylpyrrolidone rather than THF/dichloromethane as the solvent. A 0.5 molar ethanolic KOH solution was used for titration (endpoint recognition by means of potentiometry). The test substance used was castor oil with certified OH number. The reporting of the unit in mg.sub.KOH/g relates to mg[KOH]/g[product]. The OH number is related to the equivalent molar mass according to the following equation:
OH number [mg.sub.KOH/g]=56 100 [mg.sub.KOH/mol]/equivalent molar mass [g/mol]

(15) The equivalent molar mass is understood to mean the number-average total molar mass of the material containing active hydrogen atoms divided by the number of active hydrogen atoms (functionality).

(16) The acid number was determined in accordance with (DIN EN ISO 2114), except that titration was effected with a 0.5 molar methanolic potassium hydroxide solution rather than an ethanolic potassium hydroxide solution. The endpoint was recognized by means of potentiometry. The reporting of the unit in mg.sub.KOH/g relates to mg[KOH]/g[polyacid].

(17) The viscosity was determined on an Anton Paar Physica MCR 501 rheometer. A cone-plate configuration having a separation of 50 m was selected (DCP25 measurement system). 0.1 g of the substance was applied to the rheometer plate and subjected to a shear of 0.01 to 1000 l/s at 25 C., and the viscosity was measured every 10 s for 10 min. The values reported are the viscosity averaged over all the measurement points or, in the case of non-constant viscosity behavior, the maximum and minimum values measured.

(18) The glass transition temperatures (T.sub.g) were determined by DSC (differential scanning calorimetry) on the Mettler Toledo DSC 1 STAR.sup.e instrument. The sample was analyzed at a heating rate of 10 K/min over two heating cycles from 80 C. to +250 C. The glass transition temperature was determined in the second heating rate.

(19) For the reactions, an experimental apparatus consisting of two 200 mL stainless steel autoclaves which were connected via a heatable inch glass capillary (bridge) which could be shut off with a valve was used. Both reactors were equipped with a hollow shaft stirrer and manometer and were heatable independently of one another. The gas supply to reactor 1 (depolymerization reactor R1) was via an immersed tube connected to a mass flow regulator (MFC 1, capacity: 100 mL/min). The gas stream was passed through the bridge from reactor 1 into reactor 2. In reactor 2 (polymerization reactor R2) there was a gas outlet, and the offgas flow was controlled with the aid of a second mass flow regulator (MFC 2, capacity: 100 mL/min). Via MFC 1, a carrier gas stream (argon or carbon dioxide) was passed through reactor 1 with the volume flow rate {dot over (V)}.sub.in, and the depolymerization of paraformaldehyde to gaseous formaldehyde was conducted therein. The carrier gas stream enriched with formaldehyde gas was then passed through the heated bridge into reactor 2, in which the polymerization was conducted. Constant pressure in the overall system was assured by regulation of MFC 2 as a slave with the pressure transducer mounted on reactor 2.

(20) The pressure reactors used in the examples had a height (internal) of 6.84 cm and an internal diameter of 5.98 cm. The reactors were equipped with an electrical heating jacket (maximum heating power 240 watts). In addition, the reactors were equipped with an inlet tube, and each was equipped with a thermal sensor of diameter 1.6 mm which projected into the reactor up to 3 mm above the base.

(21) The hollow shaft stirrer used in the examples was a hollow shaft stirrer in which the gas was introduced into the reaction mixture via a hollow shaft in the stirrer. The stirrer body mounted on the hollow shaft had four arms and had a diameter of 25 mm and a height of 7 mm. At each end of the arm was mounted a gas outlet which had a diameter of 3 mm. The rotation of the stirrer gave rise to a reduced pressure such that the gas present above the reaction mixture (CO.sub.2 and possibly formaldehyde) was sucked in and introduced through the hollow shaft of the stirrer into the reaction mixture.

Example 1

Preparation of a Carboxylic Acid-Terminated Polyethylene Oxide-Polyoxymethylene Block Copolymer

(22) Reactor 1 was initially charged with a suspension of 30.18 g (0.335 mol) of 1,3,5-trioxane and 0.62 g (1.92 mmol) of 4-dodecylbenzenesulfonic acid in 30 ml of undecane. Reactor 2 contained a solution of 430 mg (0.68 mmol) of dibutyltin dilaurate (DBTL) and 1.09 g (3.34 mmol) of cesium carbonate in 20.11 g (33.5 mmol) of PET-1. Via a bypass line connected to MFC 1, the whole system with the bridge open was pressurized to 20 bar with CO.sub.2. Then the bridge was closed and the pressure in reactor 1 was reduced to 5 bar by means of a gas outlet valve. The reaction mixture in reactor 1 was heated to 65 C. with the bridge shut off and kept at this temperature for 1.5 hours. Subsequently, the temperature in reactor 1 was increased to 110 C. The reaction mixture in reactor 2 was heated at 60 C. while stirring. The bridge temperature was adjusted to 170 C. On attainment of the reaction temperature, the pressure in reactor 2 was adjusted to a value between 17 and 19 bar. The pressure in reactor 1 was adjusted to 20 bar with CO.sub.2 via the bypass. The bypass line was closed and a constant CO.sub.2 flow rate {dot over (V)}.sub.in=160 ml/min was established using the mass flow regulators. Directly thereafter, the bridge was opened and the total pressure in the system was adjusted to 20 bar with the aid of MFC 2. After 3.2 h, the bridge was closed, the system was cooled to room temperature and the pressure was released separately in reactor 1 and reactor 2. Subsequently, while stirring at an internal temperature of 40 C., an HPLC pump was used to introduce a solution of 7.53 g (65.9 mmol) of glutaric anhydride in 20 mL of CH.sub.2Cl.sub.2 into reactor 2 at a flow rate of 5 mL/min. After the addition had ended, the reaction mixture in reactor 2 was stirred at 100 C. for a further 16 h. Weighing of reactor 2 before the removal of the product showed an increase in weight of 3.39 g (difference in mass minus the mass of the glutaric anhydride fed in) for the reaction, which corresponds to a transfer of 3.39 g (113 mmol) of gaseous formaldehyde. 30.92 g of a viscous, colorless oil were removed from reactor 2. As a result of the transfer of 3.39 g (113 mmol) of formaldehyde, the PET-1 used as oligomer was extended by an average of 3.4 formaldehyde units per molecule, or 1.7 formaldehyde units per chain end.

(23) Viscosity: 1600 mPa.Math.s

(24) Acid number: 126.7 mg.sub.KOH/g

(25) By gel permeation chromatography (GPC) against polypropylene glycol standards, a bimodal molecular weight distribution was observed. The number-average molecular weight of the overall sample was M.sub.n=819 g/mol and the polydispersity index PDI=1.52. For the low molecular weight component (<1025 g/mol), M.sub.n=549 g/mol and the polydispersity index PDI=1.11; for the higher molecular weight component (>1025 g/mol), M.sub.n=1727 g/mol and the polydispersity index PDI=1.12.

(26) .sup.1H NMR spectroscopy (400 MHz, CDCl.sub.3): =0.47-0.62 (m, 0.045 H), 0.92 (bs, 0.14 H), 1.49-1.65 (m, 0.47 H, OC(O)CH.sub.2CH.sub.2CH.sub.2C(O)O), 1.96-2.18 (m, 1 H, OC(O)CH.sub.2CH.sub.2CH.sub.2C(O)O), 3.06-3.87 (m, 6.58 H, PET-1-CH.sub.2), 4.41-4.59 (m, 0.28 H, OCH.sub.2O), 4.79 (s, 0.26 H, OCH.sub.2O), 4.95-5.08 (m, 0.32 H, OCH.sub.2O), 5.39 (s, 0.03 H) ppm.

(27) .sup.13C APT NMR spectroscopy (400 MHz, CDCl.sub.3): =18.8 (+, OC(O)CH.sub.2CH.sub.2), 18.9 (+, OC(O)CH.sub.2CH.sub.2), 19.0 (+, OC(O)CH.sub.2CH.sub.2), 19.0 (+, OC(O)CH.sub.2CH.sub.2), 19.2 (+, OC(O)CH.sub.2CH.sub.2), 21.8 (+), 28.4 (+), 28.7 (+), 17.3 (), 31.0 (+), 32.0 (+, OC(O)CH.sub.2CH.sub.2), 32.0 (+, OC(O)CH.sub.2CH.sub.2), 32.1 (+, OC(O)CH.sub.2CH.sub.2), 32.2 (+, OC(O)CH.sub.2CH.sub.2), 32.3 (+, OC(O)CH.sub.2CH.sub.2), 60.3 (+, PET-1-CH.sub.2), 62.6 (+, PET-1-CH.sub.2), 66.6 (+, PET-1-CH.sub.2), 66.8 (+, PET-1-CH.sub.2), 68.1 (+, PET-1-CH.sub.2), 68.6 (+, PET-1-CH.sub.2), 69.2 (+, PET-1-CH.sub.2), 69.5 (+, PET-1-CH.sub.2), 71.6 (+, PET-1-CH.sub.2), 84.3 (+, OCH.sub.2O), 84.7 (+, OCH.sub.2O), 85.7 (+, OCH.sub.2O), 87.8 (+, OCH.sub.2O), 88.3 (+, OCH.sub.2O), 88.3 (+, OCH.sub.2O), 89.0 (+, OCH.sub.2O), 89.9 (+, OCH.sub.2O), 91.4 (+, OCH.sub.2O), 91.5 (+, OCH.sub.2O), 92.6 (+, OCH.sub.2O), 93.1 (+, OCH.sub.2O), 171.5 (+, C(O)OCH.sub.2), 171.6 (+, C(O)OCH.sub.2), 172.0 (+, C(O)OCH.sub.2), 174.8 (+, C(O)OH), 175.1 (+, C(O)OH) ppm.

(28) The occurrence of a multitude of signals in the .sup.1H NMR spectrum in the range of 4.4 to 5.1 ppm, and a multitude of signals having positive polarity in the .sup.13C APT NMR spectrum in the range of 83.3 to 93.1 ppm, shows the presence of chemically nonequivalent oxymethylene groups in (CH.sub.2O).sub.n, blocks having different chain lengths.

(29) Comparison of the signal intensities of the .sup.1H NMR signals for oxymethylene groups CH.sub.2O (I.sub.CH2O=0.86 H) with the signal intensities of the .sup.1H NMR signals for PET-1 CH.sub.2 groups (I.sub.PET-1=6.58 H) gives a molar ratio CH.sub.2O:(CH.sub.2).sub.2O=I.sub.CH2O:I.sub.PET-1/2=0.26. For an average chain length of 13.23 (CH.sub.2).sub.2O units per molecule, this gives an average of 3.44 oxymethylene units per molecule, or 1.72 oxymethylene units per chain end.

(30) Comparison of the signal intensities of the .sup.1H NMR signals for glutaric ester units OC(O)(CH.sub.2).sub.3C(O)O (I.sub.GSE=1.47 H) with the .sup.1H NMR signals for PET-1 CH.sub.2 groups (I.sub.PET-1=6.58 H) gives a molar ratio OC(O)(CH.sub.2).sub.3C(O)O:(CH.sub.2).sub.2O=I.sub.GSE/3:I.sub.PET-1/2=0.15. For an average chain length of 13.23 (CH.sub.2).sub.2O units per molecule, this gives an average of 1.98 glutaric ester units per molecule. The reaction of the polyoxymethylene block copolymer intermediate with glutaric anhydride accordingly proceeded with a conversion of 99%.

(31) The HMBC NMR spectrum showed long-range coupling of a PET-1 .sup.13C signal at 69.5 ppm to .sup.1H signals in the range of 4.95-5.08 ppm, which, according to HSQC NMR spectroscopy, exhibited direct coupling to .sup.13C signals at about 85 and 89 ppm. Both signals in the .sup.13C APT NMR have positive polarity and can be attributed to oxymethylene groups. In addition, the HMBC NMR spectrum showed long-range coupling of a PET-1 .sup.13C signal at about 68 ppm to .sup.1H signals in the range of 4.41-4.59 ppm, which, according to HSQC NMR spectroscopy, exhibited direct couplings to .sup.13C signals in the range of 84-93 ppm. All these .sup.13C signals in the .sup.13C APT NMR have positive polarity and can be attributed to oxymethylene groups. The .sup.13C signals of the oxymethylene groups at about 89 ppm showed long-range coupling to a .sup.1H NMR signal at about 3.4 ppm, which can be attributed to the terminal methylene groups of the PET-1. This showed that the polyethylene oxide block of the PET-1 is bonded covalently to the polyoxymethylene block.

(32) The HMBC NMR spectrum showed long-range coupling of a CO .sup.13C signal at 172 ppm, which can be attributed to the glutaric ester unit, to .sup.1H signals in the range of 4.95-5.08 ppm, which, according to HSQC NMR spectroscopy, exhibited direct coupling to .sup.13C signals at about 85 and 89 ppm. Both signals in the .sup.13C APT NMR have positive polarity and can be attributed to oxymethylene groups. This showed that the glutaric ester unit is bonded covalently to the polyoxymethylene block.

(33) These long-range couplings of PET-1 end groups on the one hand and glutaric ester units on the other hand to chemically nonequivalent oxymethylene units demonstrate clearly that polyoxymethylene blocks (CH.sub.2O).sub.n having different chain length n are present, which are bonded covalently both to PET-1 and to glutaric ester units which originate from the reaction with glutaric anhydride. The structure of the polyoxymethylene block copolymers according to the invention has thus been demonstrated beyond doubt.

(34) ESI-MS (FTMS+p):

(35) In the ESI mass spectrum, the following signal series were identified, which can be attributed to the following general empirical formulae:
[HOC(O)(CH.sub.2).sub.3C(O)O(CH.sub.2O).sub.a(C.sub.3H.sub.6O).sub.m(CHO).sub.bC(O)(CH.sub.2).sub.3C(O)OHH].sup.+ Series 1 (a+b=8): m/z (%) [m]=839 (1) [8], 883 (5) [9], 927 (14) [10], 971 (28) [11], 1015 (42) [12], 1059 (48) [13], 1103 (46) [14], 1147 (37) [15], 1191 (27) [16], 1235 (19) [17], 1279 (16) [18], 1323 (15) [19], 1367 (17) [20]. Series 2 (a+b=7): m/z (%) [m]=809 (1) [8], 853 (5) [9], 897 (16) [10], 941 (35) [11], 985 (60) [12], 1029 (75) [13], 1073 (76) [14], 1117 (64) [15], 1161 (47) [16], 1205 (32) [17], 1249 (22) [18], 1293 (18) [19], 1337 (18) [20]. Series 3 (a+b=6): m/z (%) [m]=823 (5) [9], 867 (14) [10], 911 (38) [11], 955 (69) [12], 999 (93) [13], 1043 (100) [14], 1087 (87) [15], 1131 (64) [16], 1175 (42) [17], 1219 (27) [18], 1263 (18) [19], 1307 (13) [20]. Series 4 (a+b=5): m/z (%) [m]=793 (1) [9], 837 (5) [10], 881 (12) [11], 925 (26) [12], 969 (40) [13], 1013 (48) [14], 1057 (44) [15], 1101 (33) [16], 1145 (22) [17], 1189 (18) [18], 1233 (7) [19], 1277 (2) [20]. Series 5 (a+b=4): m/z (%) [m]=939 (1) [13], 983 (5) [14], 1027 (10) [15], 1071 (17) [16], 1115 (23) [17], 1159 (26) [18], 1203 (7) [25], 1247 (21) [20]. Series 6 (a+b=3): m/z (%) [m]=909 (2) [13], 953 (5) [14], 997 (14) [15], 1041 (26) [16], 1085 (38) [17], 1129 (45) [18], 1173 (21) [25], 1217 (37) [20]. Series 7 (a+b=2): m/z (%) [m]=879 (1) [13], 923 (6) [14], 967 (15) [15], 1011 (33) [16], 1055 (51) [17], 1099 (61) [18], 1143 (62) [25], 1187 (52) [20]. Series 8 (a+b=1): m/z (%) [m]=849 (1) [13], 893 (3) [14], 937 (8) [15], 981 (19) [16], 1025 (33) [17], 1069 (44) [18], 1113 (46) [25], 1157 (40) [20].

(36) In addition, the ESI mass spectrum shows signals for block copolymers of the invention which contain polyethylene oxide units, polyoxymethylene units and three glutaric ester units, and which can be assigned to the following general empirical formula:
[HOC(O)(CH.sub.2).sub.3C(O)O(CH.sub.2O).sub.a(C.sub.3H.sub.6O).sub.m(CH.sub.2O).sub.bC(O)(CH.sub.2).sub.3C(O)O(CH.sub.2O).sub.c(C.sub.3H.sub.6O).sub.n(CH.sub.2O).sub.dC(O)(CH.sub.2).sub.3C(O)OH].sup.+ Series 9 (a+b+c+d=3): m/z (%) [m+n]=909 (1) [10], 953 (5) [11], 997 (14) [12], 1041 (27) [13], 1085 (38) [14], 1129 (45) [15], 1173 (44) [16], 1217 (37) [17], 1261 (29) [18], 1305 (21) [19], 1349 (19) [20], 1393 (20) [21], 1437 (26) [22], 1481 (32) [23], 1525 (39) [24], 1569 (45) [25], 1613 (49) [26], 1657 (49) [27], 1701 (45) [28], 1745 (39) [29], 1789 (32) [30], 1833 (25) [31], 1877 (17) [32], 1921 (12) [33], 1965 (8) [34], 2009 (5) [35], 2053 (5) [36], 2097 (2) [37]. Series 10 (a+b+c+d=2): m/z (%) [m+n]=879 (1) [10], 923 (6) [11], 967 (15) [12], 1011 (33) [13], 1055 (51) [14], 1099 (61) [15], 1143 (62) [16], 1187 (52) [17], 1231 (41) [18], 1275 (28) [19], 1319 (22) [20], 1363 (20) [21], 1407 (22) [22], 1451 (26) [23], 1495 (31) [24], 1539 (35) [25], 1583 (38) [26], 1627 (38) [27], 1671 (35) [28], 1715 (30) [29], 1759 (25) [30], 1803 (18) [31], 1847 (13) [32], 1891 (9) [33], 1935 (6) [34], 1979 (4) [35], 2023 (2) [36], 2067 (1) [37]. Series 11 (a+b+c+d=1): m/z (%) [m+n]=849 (1) [10], 893 (3) [11], 937 (9) [12], 981 (19) [13], 1025 (38) [14], 1069 (44) [15], 1113 (46) [16], 1157 (40) [17], 1201 (17) [18], 1245 (22) [19], 1289 (16) [20], 1333 (12) [21], 1377 (10) [22], 1421 (10) [23], 1465 (12) [24], 1509 (14) [25], 1553 (15) [26], 1597 (14) [27], 1641 (14) [28], 1685 (12) [29], 1729 (10) [30], 1773 (8) [31], 1817 (6) [32], 1861 (4) [33], 1905 (3) [34], 1979 (4) [35].

(37) The ESI mass spectrum shows that polymers having molecular weights of <4500 g/mol which contain, as well as polyethylene oxide units (C.sub.3H.sub.6O).sub.m, at least one polyoxymethylene block (CH.sub.2O).sub.a with a1 and at least two glutaric ester units and hence correspond to the functionalized, low molecular weight polyoxymethylene block copolymers of the invention have been obtained.

(38) IR spectroscopy: =2870 (vb), 1732 (b, [CO]), 1452 (w), 1411 (vw), 1349 (w), 1295 (vw), 1246 (w), 1093 (m), 994 (vw), 928 (m), 846 (w), 523 (w) cm.sup.1.

(39) The IR spectrum is neither identical to the IR spectrum of paraformaldehyde nor to the IR spectrum of PET-1. The CO stretch vibration at 1732 cm.sup.1 can be attributed to the glutaric ester units and is not identical to the CO stretch vibration of glutaric anhydride. The occurrence of this band demonstrates that the reaction of the terminal OH groups with glutaric anhydride was successful.

(40) Inventive example 1 accordingly shows the preparation of a polyoxymethylene block copolymer and subsequent conversion of the OH-functional end groups of the resultant polymer to carboxylate groups.

Example 2

Preparation of a Carboxylic Acid-Terminated Polyethylene Oxide-Polymethylene Block Copolymer

(41) Reactor 1 was initially charged with a suspension of 29.83 g (0.331 mol) of 1,3,5-trioxane and 0.52 g (1.6 mmol) of 4-dodecylbenzenesulfonic acid in 30 ml of undecane. Reactor 2 contained a mixture of 460 mg (0.73 mmol) of dibutyltin dilaurate (DBTL), 22.6 g (69.5 mmol) of cesium carbonate and 20.5 g (34.2 mmol) of PET-1. Via a bypass line connected to MFC 1, the whole system with the bridge open was pressurized to 20 bar with CO.sub.2. Then the bridge was closed and the pressure in reactor 1 was reduced to 5 bar by means of a gas outlet valve. The reaction mixture in reactor 1 was heated to 65 C. with the bridge shut off and kept at this temperature for 1.5 hours. The reaction mixture in reactor 2 was heated at 60 C. while stirring. The bridge temperature was adjusted to 170 C. Once the reaction mixture in reactor 1 had been heated to 65 C. for 1.5 hours, the pressure was adjusted to 20 bar with CO.sub.2 via the bypass. The pressure in reactor 2 was adjusted to a value between 17 and 19 bar. The bypass line was closed and a constant CO.sub.2 flow rate {dot over (V)}.sub.in=160 ml/min was established using the mass flow regulators. The total pressure in the system was kept constant at 20 bar for the rest of the experiment with the aid of MFC 2. Then the temperature in reactor 1 was increased to 110 C. with the bridge open under a constant CO.sub.2 flow. After 6 h, the bridge was closed and reactor 2 was cooled to 40 C. Subsequently, while stirring at an internal temperature of 40 C., an HPLC pump was used to introduce a solution of 7.53 g (65.9 mmol) of glutaric anhydride in 20 mL of 1,4-dioxane into reactor 2 at a flow rate of 5 mL/min. After the addition had ended, the reaction mixture in reactor 2 was stirred at 100 C. for a further 16 h. Subsequently, the system was cooled to room temperature and pressure in reactor 1 and 2 was released separately. A viscous, colorless oil was removed from reactor 2.

(42) Viscosity: The product showed shear-thickening behavior in the shear rate range from 10 to 162 s.sup.1, and shear-thinning behavior in the shear rate range from 162 to 1000 s.sup.1. Viscosity at shear rate 10 s.sup.1: 3056 mPa.Math.s Viscosity at shear rate 162 s.sup.1: 3173 mPa.Math.s Viscosity at shear rate 1000 s.sup.1: 2986 mPa.Math.s

(43) .sup.1H NMR spectroscopy (400 MHz, CDCl.sub.3): =0.75-0.88 (m, 0.359 H), 1.12-1.27 (m, 1.082 H), 1.78-1.96 (m, 2.988 H, C(O)CH.sub.2CH.sub.2CH.sub.2C(O)OH), 2.20-2.43 (m, 6.099 H, C(O)CH.sub.2CH.sub.2CH.sub.2C(O)OH), 3.36-3.44 (m, 0.311 H, PET-1-CH.sub.2), 3.44-3.69 (m, 45.87 H, PET-1-CH.sub.2), 3.69-3.80 (m, 2.148 H, PET-1-CH.sub.2), 4.10-4.20 (m, 0.656 H), 4.70-4.80 (m, 1.595 H, OCH.sub.2O), 4.80-4.90 (m, 1.602 H, OCH.sub.2O), 5.09 (s, 0.433 H, OCH.sub.2O), 5.19-5.26 (m, 1.112 H, OCH.sub.2O), 5.26-5.31 (m, 0.999 H, OCH.sub.2O), 9.17 (bs, 1.859 H) ppm.

(44) The occurrence of a multitude of signals in the .sup.1H NMR spectrum in the range of 4.7 to 5.3 ppm shows the presence of chemically nonequivalent oxymethylene groups in (CH.sub.2O), blocks having different chain lengths.

(45) Comparison of the signal intensities of the .sup.1H NMR signals for oxymethylene groups CH.sub.2O (I.sub.CH2O=5.74 H) with the signal intensities of the .sup.1H NMR signals for PET-1 CH.sub.2 groups (I.sub.PET-1=48.33 H) gives a molar ratio CH.sub.2O:(CH.sub.2).sub.2O=I.sub.CH2O:I.sub.PET-1/2=0.24. For an average chain length of 13.23 (CH.sub.2).sub.2O units per molecule, this gives an average of 3.16 oxymethylene units per molecule.

(46) Comparison of the signal intensities of the .sup.1H NMR signals for glutaric ester units OC(O)(CH.sub.2).sub.3C(O)O (I.sub.GSE=9.09 H) with the .sup.1H NMR signals for PET-1 CH.sub.2 groups (I.sub.PET-1=48.33 H) gives a molar ratio OC(O)(CH.sub.2).sub.3C(O)O:(CH.sub.2).sub.2O=I.sub.GSE/3:I.sub.PET-1/2=0.13. For an average chain length of 13.23 (CH.sub.2).sub.2O units per molecule, this gives an average of 1.72 glutaric ester units per molecule. The reaction of the polyoxymethylene block copolymer intermediate with glutaric anhydride accordingly proceeded with a conversion of 86%.

(47) IR spectroscopy: =2867 (m), 1732 (m, [CO]), 1558 (vw), 1452 (w), 1412 (w), 1350 (w), 1291 (w), 1247 (w), 1097 (vs), 1040 (m), 995 (m), 946 (m), 871 (m), 848 (m), 614 (vw), 523 (w) cm.sup.1.

(48) The IR spectrum is neither identical to the IR spectrum of paraformaldehyde nor to the IR spectrum of PET-1. The CO stretch vibration at 1732 cm.sup.1 can be attributed to the glutaric ester units and is not identical to the CO stretch vibration of glutaric anhydride. The occurrence of this band demonstrates that the reaction of the terminal OH groups with glutaric anhydride was successful.

(49) Inventive example 2 accordingly shows the preparation of a polyoxymethylene block copolymer and subsequent conversion of the OH-functional end groups of the resultant polymer to carboxylate groups.

Example 3

Reaction of the Carboxylic Acid-Terminated Polyethylene Oxide-Polyoxymethylene Block Copolymer Obtained in Example 2 with Isocyanate 1

(50) A beaker was initially charged with 5.02 g of the carboxylic acid-terminated polyethylene oxide-polyoxymethylene block copolymer obtained in example 2, 0.25 mL of water and 10.3 mg (0.016 mmol) of dibutyltin dilaurate (DBTL), and the mixture was heated to 60 C. Subsequently, 0.62 g of isocyanate 1 was added while stirring and the mixture was stirred vigorously. After 3 s, significant foam formation was observed, which had abated after 20 s. A yellow gel was obtained.

(51) Unlike the starting materials, the resultant product was insoluble in dichloromethane and THF. This showed that reaction with isocyanate 1 gave an insoluble polymer of higher molecular weight. Viscosity: The product showed shear-thinning behavior. Viscosity at shear rate 0.01 s.sup.1: 10 500 mPa.Math.s Viscosity at shear rate 927 s.sup.1: 8684 mPa.Math.s

(52) The viscosity was distinctly increased over the entire shear rate measurement range compared to the carboxylic acid-terminated polyethylene oxide-polyoxymethylene block copolymer obtained in example 2 and used here (viscosity between 2986 and 3173 mPa.Math.s). This showed that a reaction with isocyanate 1 to give a polymer of higher molecular weight was successful.

(53) Example 3 thus demonstrates the reaction of a carboxylic acid-terminated polyoxymethylene block copolymer with a diisocyanate to give a polymer of higher molecular weight.

Example 4

Reaction of the Carboxylic Acid-Terminated Polyethylene Oxide-Polyoxymethylene Block Copolymer Obtained in Example 2 with Phenyl Glycidyl Ether

(54) 5.04 g of the carboxylic acid-terminated polyethylene oxide-polyoxymethylene block copolymer obtained in example 2 were weighed into a glass flask together with 26.7 mg (0.102 mmol) of triphenylphosphine and 1.41 g (9.39 mmol) of phenyl glycidyl ether (PGE), and the mixture was stirred at 80 C. under reflux for 18 h, in the course of which the mixture changed color from yellow to dark red. The product was used further as obtained. Viscosity: The product showed shear-thinning behavior. Viscosity at shear rate 0.01 s.sup.1: 3890 mPa.Math.s Viscosity at shear rate 589 s.sup.1: 3658 mPa.Math.s Viscosity at shear rate 1000 s.sup.1: 3574 mPa.Math.s T.sub.g=42.59 C.

(55) .sup.1H NMR spectroscopy (400 MHz, CDCl.sub.3): =0.79-0.88 (m, 0.135 H), 1.15-1.30 (m, 0.465 H), 1.81-2.01 (m, 1.971 H, C(O)CH.sub.2CH.sub.2CH.sub.2C(O)), 2.17-2.49 (m, 3.892 H, C(O)CH.sub.2CH.sub.2CH.sub.2C(O)), 3.38-3.45 (m, 0.181 H), 3.45-3.72 (m, 29.28 H, PET-1-CH.sub.2), 3.72-3.88 (m, 1.301 H, PET-CH.sub.2), 3.91-4.02 (m, 1.622 H), 4.02-4.36 (m, 5.773 H, PGE-CH/PGE/CH.sub.2), 4.36-4.50 (0.257 H), 4.74-4.82 (m, 0.256H, OCH.sub.2O), 4.82-4.89 (m, 0.243 H, OCH.sub.2O), 5.12 (s, 0.187 H, OCH.sub.2O), 5.15-5.39 (m, 0.956 H), OCH.sub.2O), 6.80-6.97 (m, 3.000 H, PGE-CH.sub.ar), 7.17-7.39 (m, 2.160 H, PGE-CH.sub.ar/CHCl.sub.3), 7.39-7.48 (m, 0.105 H, PPh.sub.3), 7.48-7.55 (m, 0.0458 H, PPh.sub.3), 7.57-7.67 (m, 0.0896 H, PPh.sub.3) ppm.

(56) The .sup.1H NMR spectrum showed new signals in the range of 4.02-4.38 ppm and in the aromatic range (6.80-7.39 ppm), which indicate the incorporation of phenyl glycidol ether in the form of 2-hydroxy-3-phenoxypropyloxy groups PhOCH.sub.2CH(OH)CH.sub.2O (assigned as PGE-CH.sub.2 or PGE-CH and PGE-CH.sub.ar). The ratio of the integrals for PGE-CH.sub.ar (6.80-6.97 ppm, 3 H) and C(O)CH.sub.2CH.sub.2CH.sub.2C(O) (1.81-2.01 ppm, 1.971 H) showed that the reaction of the terminal carboxylic acid groups with phenyl glycidyl ether proceeded quantitatively.

Example 5

Reaction of the Hydroxy-Functionalized Polyethylene Oxide-Polyoxymethylene Block Copolymer Obtained in Example 4 with Isocyanate 1

(57) A beaker was initially charged with 4.13 g of the hydroxy-functionalized polyethylene oxide-polyoxymethylene block copolymer obtained in example 4, 0.25 mL of water and 8.0 mg (0.013 mmol) of DBTL, and the mixture was heated to 60 C. Subsequently, 0.62 g of isocyanate 1 was added while stirring and the mixture was stirred vigorously. After 4 s, significant foam formation was observed, which had abated after 20 s. A brown gel was obtained.

(58) Unlike the starting materials, the resultant product was insoluble in dichloromethane and THF. This showed that reaction with isocyanate 1 gave an insoluble polymer of higher molecular weight. Viscosity: The product showed shear-thinning behavior. Viscosity at shear rate 3.35 s.sup.1: 1 447 000 mPa.Math.s Viscosity at shear rate 1000 s.sup.1: 31 950 mPa.Math.s

(59) The viscosity was distinctly increased over the entire shear rate measurement range compared to the hydroxy-functionalized polyethylene oxide-polyoxymethylene block copolymer obtained in example 4 and used here (viscosity between 3574 and 3890 mPa.Math.s). This showed that a reaction with isocyanate 1 to give a polymer of higher molecular weight was successful. T.sub.g=29.41 C.

(60) Compared to the hydroxy-functionalized polyethylene oxide-polyoxymethylene block copolymer obtained in example 4 and used here (T.sub.g=42.59 C.), the glass transition temperature after reaction with isocyanate 1 was distinctly increased. This showed that the reaction of the hydroxy-functionalized polyethylene oxide-polyoxymethylene block copolymer with isocyanates was successful.

(61) After the reaction of the hydroxy-functionalized polyethylene oxide-polyoxymethylene block copolymer obtained in example 4 with isocyanate 1, the viscosity and glass transition temperature were distinctly increased. This showed that a reaction with isocyanate 1 to give a polyurethane polymer of higher molecular weight had taken place.

(62) Examples 4 and 5 thus demonstrate the reaction of a carboxylic acid-terminated polyethylene oxide-polyoxymethylene block copolymer with epoxides to give a hydroxy-functionalized polyethylene oxide-polyoxymethylene block copolymer and the subsequent reaction thereof with a diisocyanate to give a polyurethane polymer.