Method for producing a diblock copolymer

Abstract

The present invention relates to a process for producing a diblock copolymer comprising the reaction of at least one aromatic polyester having a melting point in the range from 160° C. to 350° C. and at least one polymer diol having a melting point of less than 100° C. at a temperature of greater than 200° C. to obtain a mixture (G-a); and the reaction of the mixture (G-a) with at least one diisocyanate, wherein the diisocyanate is employed in a molar amount of at least 0.9 based on the alcohol groups of the polymer diols. The present invention further relates to diblock copolymers obtained or obtainable according to such a process and to the use of such diblock copolymers for producing extruded, injection molded and pressed articles and also foams, cable sheaths, hoses, profiles, drive belts, fibers, nonwovens, films, moldings, plugs, housings, damping elements for the electricals industry, automotive industry, mechanical engineering, 3-D printing, medicine and consumer goods.

Claims

1. A process for producing a diblock copolymer, comprising: (a) contacting an aromatic polyester having a melting point in the range from 160° C. to 350° C. and a polymer diol having a melting point of less than 100° C. at a temperature of greater than 200° C. and polymerizing by transesterification to obtain a mixture (G-a); (b) reacting the mixture (G-a) with a diisocyanate to form the diblock copolymer, wherein at least 0.9 moles of the diisocyanate are reacted with the mixture (G-a) based on a molar amount of the hydroxyl groups of the polymer diol present in the reacting (a), wherein the aromatic polyester is selected from the group consisting of polybutylene terephthalate (PBT), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

2. The process according to claim 1, wherein the polymerizing (a) is carried out by continuously mixing the aromatic polyester while adding the polymer diol to the aromatic polyester.

3. The process according to claim 1, wherein the polymerizing (a) is carried out in an extruder.

4. The process according to claim 1, wherein the reacting (b) is carried out at a temperature in the range from 170° C. to 260° C.

5. The process according to claim 1, wherein the diisocyanate is selected from the group consisting of 2,2′-, 2,4′- and/or 4,4′-diphenylmethanediisocyanate (MDI), 2, 4- and/or 2,6-tolylenediisocyanate (TDI), 4,4′-, 2,4′- and/or 2,2′-methylenedicyclohexyldiisocyanate (H12MDI), hexamethylenediisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI).

6. The process according to claim 1, wherein the polymer diol is a polyether diol.

7. The process according to claim 1, wherein the polymer diol is a polytetrahydrofuran.

8. The process according to claim 1, wherein no dicarboxylic acids are reacted with the aromatic polyester during the reacting (a).

9. A diblock copolymer obtained by a process according to claim 1.

10. The process according to claim 1, further comprising: forming, by at least one selected from the group consisting of extruding, injection molding and pressing the diblock copolymer, to produce an article, a foam, a cable sheath, a hose hoses, a profile, a drive belt, a fiber, a nonwoven, a film, a molding, a plug, a housing, or a damping element.

11. The process of claim 1, wherein the polymerizing (a) includes first melting the aromatic polyester in an extruder then adding the polymer diol to the molten aromatic polyester to transesterify the aromatic polyester and the polymer diol, then adding the diisocyanate to the transesterified mixture of the aromatic polyester and the polymer polyol, in the same extruder, to form the diblock copolymer.

12. The process according to claim 11, wherein the diblock copolymer includes a hard phase and a soft phase, wherein the hard phase represents polyester fragment portions of the transesterification product and the soft phase represents polymer diol portions of the transesterification product.

13. The process according to claim 11, wherein the diisocyanate reacts with acid and alcohol groups on the transesterification product to form the block copolymer.

14. The process according to claim 12, wherein the soft phase of the diblock copolymer has a molecular weight of greater than 500 g/mol and a glass transition point of less than −20° C.

15. The process according to claim 11, wherein the diblock copolymer has: a shore D modulus of elasticity of from 49 to 70 MPa according to DIN 7619-1, a tensile strength of 30-66 MPa according to DIN 53-504, an elongation at break of 430-620% according to DIN53-504, a tear propagation resistance of 135-204 kN/M according to DIN ISO 24-1 B, and a compression set of 21-25% at 72 h/23° C./30 min according to DIN ISO 815.

16. The process of claim 1, wherein during the polymerizing (a) the molten aromatic polyester is transesterified with only polymeric diol.

Description

EXAMPLES

(1) 1. The Following Input Materials Were Employed: Polyol 1: polybutylene terephthalate (PBT) having a weight average molecular weight of 60 000 g/mol Polyol 2: Polyether polyol having an OH number of 174.7 and exclusively primary OH groups (based on tetramethylene oxide, functionality: 2) Polyol 3: Polyether polyol having an OH number of 112.2 and exclusively primary OH groups (based on tetramethylene oxide, functionality: 2) Polyol 4: mixture of 53.33% polyol 3 and 46.67% polyol 5 Polyol 5: Polyether polyol having an OH number of 55.8 and exclusively primary OH groups (based on tetramethylene oxide, functionality: 2) Polyol 6: Polyether polyol having an OH number of 45.5 and exclusively primary OH groups (based on butanediol and adipic acid, functionality: 2) Isocyanate 1: aromatic isocyanate (4,4′ methylenediphenyldiisocyanate) Isocyanat 2: aliphatic isocyanate (1,6-hexamethylenediisocyanate) Catalyst 1: tin(II) dioctoate (10% strength in dioctyl adipate) Antioxidant: sterically hindered phenol Hydrolysis stabilizer 1: polymeric carbodiimide Hydrolysis stabilizer 2: epoxidized soybean oil

(2) 2. Continuous Synthesis Example

(3) The polyester (PBT) is fed into the first barrel of a Coperion ZSK58 twin screw extruder with a processing length of 48D. After the melting of the polyester the polyol, and any catalyst present therein, are added in barrel 3. The transesterification is effected at barrel temperatures of 250-300° C. before in the fifth barrel the diisocyanate is added to the reaction mixture. The molar mass increase is effected downstream at barrel temperatures of 190-230° C. Following the synthesis the obtained polymer is underwater or strand pelletized and then dried.

(4) The Amounts Employed are Summarized in Tables 1 and 2.

(5) TABLE-US-00001 TABLE 1 Synthesis examples: Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Polyol 1 60 60 60 60 60 60 [parts] Polyol 2 12 12 12 24 24 36 [parts] Iso 1 4.62 4.71 4.81 9.24 9.43 13.86 [parts]

(6) TABLE-US-00002 TABLE 2 Synthesis examples: Example 7 Example 8 Example 9 Example 10 Polyol 1 [parts] 60 60 60 60 Polyol 2 [parts] 36 36 Polyol 3 [parts] 36 Polyol 4 [parts] 36 Polyol 5 [parts] Iso 1 [parts] 9.19 14.61 7.03 Iso 2 [parts] 9.14 UV stab. 1 1 Hydrolysis stab. 1 1 Hydrolysis stab. 2 0.5

(7) The properties of the thermoplastic polyurethanes produced by the continuous synthesis are summarized in table 3 and table 4.

(8) TABLE-US-00003 TABLE 3 Properties examples: Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Shore D 70 69 70 59 62 49 Modulus of elasticity [MPa] Tensile strength 45 43 45 30 33 66 [MPa] Elongation at break 460 460 430 720 480 620 [%] Tear propagation 196 192 204 135 160 127 resistance [kN/m] Compression set 22 25 24 23 23 21 (72 h/23° C./30 min) [%] Compression set 47 43 47 46 47 44 (24 h/70° C./30 min) [%] Compression set 40 46 49 45 49 42 (24 h/100° C./30 min) [%] Abrasion [mm.sup.3] 30 26 26 19 17 19 TMA onset temperature 199 199 198 182 178 164 (ΔT 20° C./Min) [° C.]

(9) TABLE-US-00004 TABLE 4 Properties examples: Exam- Exam- Exam- Exam- ple 7 ple 8 ple 9 ple 10 Shore D 50 47 48 49 Modulus of elasticity [MPa] Tensile strength [MPa] 31 28 34 37 Elongation at break [%] 630 620 580 640 Tear propagation 113 98 117 111 resistance [kN/m] Compression set (72 h/23° C./30 min) [%] Compression set (24 h/70° C./30 min) [%] Compression set (24 h/100° C./30 min) [%] Abrasion [mm.sup.3] 22 21 24 32 TMA onset temperature (ΔT 20° C./Min) [° C.]

(10) 3. Methods of Measurement:

(11) The methods of measurement that may be utilized for material characterization include: DSC, DMA, TMA, NMR, FT-IR, GPC, bursting pressure measurement

(12) TABLE-US-00005 Shore D hardness DIN 7619-1 Modulus of elasticity DIN 53 504 Tensile strength DIN 53 504 Elongation at break DIN 53504 Tear propagation resistance DIN ISO 34-1, B Abrasion DIN 4649 Compression set DIN ISO 815 Creep behavior DIN EN ISO 899-1