ADHESIVES BASED ON CARBODIMIDE CHEMISTRY

Abstract

Described herein is a thermosetting resin composition, obtained from the reaction of at least: a polycarbodiimide (i), where the number of carbodiimide groups per molecule is in the range of from 1 to 10; a mixture of crystalline and amorphous polyols (ii), where the molar ratio of carbodiimide groups in the polycarbodiimide according to (i) to hydroxyl groups in the mixture according to (ii) is in the range of from 1:2 to 2:1 and where at least 25 weight-% of the mixture according to (ii) consists of at least one crystalline polyesterol, based on the overall weight of the mixture being 100 weight-%. Also described herein is a method of using the thermosetting resin composition as an adhesive, as well as processes for preparation of adhesives, an element including an adhesive layer on at least one substrate, and an adhesive film, obtained from one of the processes.

Claims

1. A thermosetting resin composition, obtained from the reaction of at least: i) a polycarbodiimide, wherein the number of carbodiimide groups per molecule is in the range of from 1 to 10; and ii) a mixture of crystalline and amorphous polyols, wherein the molar ratio of carbodiimide groups in the polycarbodiimide according to (i) to hydroxyl groups in the mixture according to (ii) is in the range of from 1:2 to 2:1, and wherein at least 25 weight-% of the mixture according to (ii) consists of at least one crystalline polyesterol, based on the overall weight of the mixture being 100 weight-%.

2. The thermosetting resin composition according to claim 1, wherein the polycarbodiimide according to (i) is obtained from the reaction of at least: i.1) a polyisocyanate composition comprising at least one diisocyanate; and i.2) a monofunctional compound selected from the group consisting of a monoisocyanate, an isocyanate reactive monofunctional compound, wherein the isocyanate reactive monofunctional compound is selected from the group consisting of a monoalcohol, a monothiol, a monoamine, and mixtures of two or more of these isocyanate reactive monofunctional compounds, and a mixture of monoisocyanate and isocyanate reactive monofunctional compound; in the presence of a carbodiimidization catalyst (i.3).

3. The thermosetting resin composition according to claim 1, wherein the polycarbodiimide according to (i) is obtained by a) mixing the polyisocyanate composition according to (i.1) with at least a part of the monofunctional compound according to (i.2) at a temperature T.sub.1 thereby obtaining a first mixture; b) adding the catalyst (i.3) to the first mixture obtained in (a) at a temperature T.sub.2 wherein T.sub.2 is >T.sub.1, thereby obtaining a precursor compound; c) adjusting the precursor compound obtained in (b) to a temperature T.sub.3; and d) adding the remaining part of the monofunctional compound according to (i.2) at temperature T.sub.3; thereby obtaining the polycarbodiimide according to (i); wherein: T.sub.1 is a temperature below 70° C.; T.sub.2 is a temperature ≥70° C.; and T.sub.3 is a temperature below 100° C.

4. The thermosetting resin composition according to claim 1, wherein the at least one crystalline polyesterol of the mixture according to (ii) has a melting temperature >30° C.

5. The thermosetting resin composition according to claim 1, wherein the at least one crystalline polyesterol of the mixture according to (ii) has a molecular weight in the range of from 500 to 5000 g/mol.

6. The thermosetting resin composition according to claim 1, wherein at least 50 weight-% of the mixture of crystalline and amorphous polyols consists of at least one crystalline polyesterol, based on the overall weight of the mixture being 100 weight-%.

7. The thermosetting resin composition according to claim 1, wherein the at least one crystalline polyesterol of the mixture according to (ii) is a saturated polyesterol based on at least: (ii.1) a compound having at least two hydroxyl groups reactive towards ester formation; and (ii.2) a compound having at least two carboxyl groups reactive towards ester formation.

8. The thermosetting resin composition according to claim 1, wherein the at least one crystalline polyesterol of the mixture according to (ii) is a polyesterol based on a C2 to C10 dicarboxylic acid selected from the group consisting of adipic acid, azelaic acid sebacic acid, 12-dodecanedioic acid and mixtures of two or more of these dicarboxylic acids and a diol which is hexane-1,6-diol, neopentylglycol or a mixture of hexane-1,6-diol and neopentylglycol; or wherein the at least one crystalline polyesterol of the mixture according to (ii) is a saturated polyesterol based on at least an alpha-omega-hydroxy-carboxylic acid, a cyclic oligomer of an alpha-omega-hydroxy-carboxylic acid or a mixture of two or more thereof.

9. The thermosetting resin composition according to claim 1, obtained from the reaction of at least: i) a polycarbodiimide, wherein the number of carbodiimide groups per molecule is in the range of from 1 to 10; and ii) a mixture of crystalline and amorphous polyols, wherein the molar ratio of carbodiimide groups in the polycarbodiimide according to (i) to hydroxyl groups in the mixture according to (ii) is in the range of from 1:2 to 2:1, and wherein at least 25 weight-% of the mixture according to (ii) consists of at least one crystalline polyesterol, based on the overall weight of the mixture being 100 weight-%; optionally in the presence of a catalyst (iii); wherein the polycarbodiimide according to (i) is a toluene diisocyanate-based polycarbodiimide obtained from the reaction of at least: i.1) a polyisocyanate composition comprising at least TDI; and i.2) a monofunctional compound which is 2-ethyl hexan-1-ol; in the presence of a carbodiimidization catalyst (i.3); and wherein the at least one crystalline polyesterol of the mixture according to (ii) is a crystalline saturated copolyester based on hexane-1,6-dicarboxylic acid and hexane-1,6-diol.

10. A method of using the thermosetting resin composition according to claim 1, the method comprising using the thermosetting resin composition as an adhesive.

11. A process for preparation of an adhesive, comprising a) mixing at least: i) a polycarbodiimide, wherein the number of carbodiimide groups per molecule is in the range of from 1 to 10; ii) a mixture of crystalline and amorphous polyols; and iii) a catalyst; wherein the molar ratio of carbodiimide groups in the polycarbodiimide according to (i) to hydroxyl groups in the polyesterol according to (ii) is in the range of from 1:2 to 2:1, and wherein at least 25 weight-% of the mixture according to (ii) consists of at least one crystalline polyesterol, based on the overall weight of the mixture being 100 weight-%; wherein the mixing according to (a) is done at a temperature above the melting temperature Tm of the at least one polyesterol of the mixture according to (ii), thereby obtaining a mixture; b) applying the mixture obtained from (a) to at least one substrate, wherein the substrate has a temperature above 0° C., wherein applying is done at a temperature of the mixture above the melting temperature Tm of the at least one crystalline polyesterol of the mixture according to (ii); and c) optionally curing the mixture on the at least one substrate at a temperature above the melting temperature Tm of the at least one crystalline polyesterol of the mixture according to (ii); thereby obtaining an element comprising an adhesive layer on at least one substrate.

12. The process according to claim 11, wherein the at least one substrate comprises a first and a second substrate, wherein (b) comprises: b.1) applying the mixture obtained from (a) at least partially on at least one surface of the first substrate, wherein the substrate has a temperature above 0° C., wherein applying is done at a temperature of the mixture above the melting temperature Tm of the at least one crystalline polyesterol of the mixture according to (ii), thereby obtaining a first substrate having a surface at least partially coated with the mixture obtained from (a); and b.2) positioning the second substrate at least partially onto the coated surface of the first substrate, thereby obtaining an element comprising the first and second substrate and the mixture obtained from (a) between them; and (c) comprises curing the mixture between first and second substrate at a temperature above the melting temperature Tm of the at least one crystalline polyesterol of the mixture according to (ii), thereby obtaining an element comprising first and second substrates and an adhesive layer between them.

13. A process for preparation of an adhesive, comprising a) mixing at least: i) a polycarbodiimide, wherein the number of carbodiimide groups per molecule is in the range of from 1 to 10; ii) a mixture of crystalline and amorphous polyols; and iii) a catalyst; wherein the molar ratio of carbodiimide groups in the polycarbodiimide according to (i) to hydroxyl groups in the mixture according to (ii) is in the range of from 1:2 to 2:1; and wherein at least 25 weight-% of the mixture according to (ii) consists of at least one crystalline polyesterol, based on the overall weight of the mixture being 100 weight-%; wherein the mixing according to (a) is done at a temperature above the melting temperature Tm of the crystalline polyesterol of the mixture according to (ii), thereby obtaining a mixture; b′) casting the mixture obtained according to (a) on a surface of at least one substrate having a temperature in the range of from 0 to 150° C., thereby obtaining an adhesive film on the surface; and c′) optionally removing the adhesive film obtained according to (b′) from the surface.

14. An element comprising an adhesive layer on at least one substrate, obtained from the process of claim 11.

15. An adhesive film, obtained from the process according to claim 13.

16. The thermosetting resin composition according to claim 1, wherein the at least one crystalline polyesterol of the mixture according to (ii) is a saturated polyesterol based on at least: (ii.1) a compound having at least two hydroxyl groups reactive towards ester formation; and (ii.2) a compound having at least two carboxyl groups reactive towards ester formation; wherein: the compound (ii.1) having at least two hydroxyl groups reactive towards ester formation is a saturated diol selected from the group consisting of 1,2-ethane diol, diethylene glycol, 1,2-propane diol, dipropylene glycol, 1,4-butane diol, 1,5-pentane diol, 1,6-hexane diol, neopentylglycol, and mixtures of two or more of these diols; and the compound (ii.2) having at least two carboxyl groups reactive towards ester formation is selected from the group consisting of saturated dicarboxylic acid, anhydride of a saturated dicarboxylic acid, ester of a saturated dicarboxylic acid, and mixtures of two or more of these components.

17. An element comprising an adhesive layer on at least one substrate, obtained from the process of claim 13.

18. The thermosetting resin composition according to claim 1, wherein the polycarbodiimide according to (i) is obtained by a) mixing the polyisocyanate composition according to (i.1) with at least a part of the monofunctional compound according to (i.2) at a temperature T.sub.1 thereby obtaining a first mixture; b) adding the catalyst (i.3) to the first mixture obtained in (a) at a temperature T.sub.2 wherein T.sub.2 is >T.sub.1, thereby obtaining a precursor compound; c) adjusting the precursor compound obtained in (b) to a temperature T.sub.3; and d) adding the remaining part of the monofunctional compound according to (i.2) at temperature T.sub.3; thereby obtaining the polycarbodiimide according to (i); wherein: T.sub.1 is a temperature in the range of from 5 to <70° C.; T.sub.2 is a temperature in the range of from ≥70 to 150° C.; and T.sub.3 is a temperature in the range of from 5 to 100° C.

19. The thermosetting resin composition according to claim 1, wherein the at least one crystalline polyesterol of the mixture according to (ii) has a melting temperature in the range of from >30 to 80° C.

20. The thermosetting resin composition according to claim 1, wherein at least 75 weight-% of the mixture of crystalline and amorphous polyols consists of at least one crystalline polyesterol, based on the overall weight of the mixture being 100 weight-%, wherein (ii) consists of one or more crystalline polyesterols.

Description

EXAMPLES

1. Chemicals

[0213]

TABLE-US-00001 TABLE 1 Components used Characteristic Ingredient Structure properties Polyesterol 1 Partially crystalline saturated HV 30 mg KOH/g; (cPESOL) copolyester based on hexane- melting point 55° C.*; 1,6-dicarboxylic acid and molecular weight hexane-1,6-diol 3500 g/mol Polyesterol 2 Amorphous saturated copolyester HV 348 mg KOH/g Polyetherol 1 Polyether polyol HV 400 mg KOH/g Polyetherol 2 Polypropylene glycol HV 56 mg KOH/g Polyetherol 3 Polypropylene glycol HV 104 mg KOH/g Diol 1,4-Butanediol HV 1245 mg KOH/g Catalyst 1 3-methyl-1-phenyl-2-phospholene 1-oxide (MPPO) Catalyst 2 Dimethyl tin carboxylate AV 215 mg KOH/g Isocyanate TDI 80 (80:20 mixture of the NCO content 48.2% 2,4- and 2,6-isomers of toluene diisocyanate) *Melting point of cPESOL as indicated by supplier

2. Measuring Methods

[0214] Hydroxyl value (HV): DIN 53240 [0215] Acid value (AV): DIN EN ISO 14898 [0216] NCO content: DIN EN ISO 14896 [0217] N═C═N content: oxalic acid method published by W. Adam and F. Yany, 676 Analytical Chemistry, Vol. 49, No. 4, April 1977 [0218] residual TDI monomer: DIN EN ISO 10283 [0219] lap shear strength: Sample preparation ISO 4587/DIN EN 1465, measurement ISO 4587/DIN EN 6060 [0220] tensile force: ISO 4587/DIN EN 6060 [0221] Shear Adhesion Failure Temperature (SAFT): analogy to ASTM D4498 using an air circulated oven

3. Reference Example, Examples and Comparative Examples

Reference Example 1—Preparation of a Toluene Diisocyanate-Based Polycarbodiimide (pCDI)

[0222] A 80:20 mixture of the 2,4- and 2,6-isomers of toluene diisocyanate (TDI) (500.0 g) was placed in a flask and cooled with a water/ice bath. While stirring 2-ethyl hexan-1-ol (157.2 g) was added dropwise, maintaining temperature below 25° C. After completion of the reaction the content of the flask was heated to 100° C. When reaching 75° C., 30.0 g of Catalyst 1 (3-methyl-1-phenyl-2-phospholene 1-oxide, MPPO) solution (5 wt % in butyl acetate) was added and after reaching 100° C., the mixture was stirred at a constant temperature of 100° C. for 75 min. The product was cooled below 50° C. and the NCO content (determined according to DIN EN ISO 14896: Plastics—Polyurethane raw materials—Determination of isocyanate content) was determined as 9.49 wt %. Based on the NCO content another 178.6 g of 2-ethyl hexan-1-ol was added dropwise to achieve a theoretical NCO content of 0.0 wt % maintaining temperatures below 70° C. After complete addition the mixture was stirred at 60° C. until the reaction was finished. The material was left at room temperature overnight. For transfer to another container it was heated to 70° C. The N═C═N content (determined according to the oxalic acid method published by W. Adam and F. Yany, 676 Analytical Chemistry, Vol. 49, No. 4, April 1977) was determined as 6.90 wt %, NCO content as 0.17 wt % and residual TDI monomer (determined according to DIN EN ISO 10283: Binders for paints and varnishes - Determination of monomeric diisocyanates in polyisocyanate resins) as <0.01 wt %. The butyl acetate was removed using a rotary evaporator at 10 mbar and an oil bath at 100° C.

Examples 2-7—2 K Adhesives

[0223] Description of the 2 K experimental procedure:

[0224] The samples for the determination of the lap shear strength (lap shear strength 0.3 mm) were prepared in close accordance to ISO 4587/DIN EN 1465; the compositions are indicated in Table 2. Adhesive compositions according to Table 2 were prepared in that polyesterol 1 and pCDI of Reference Example 1 were both conditioned at 90° C. Catalyst 2 was added to Polyesterol 1 and premixed using a spatula. The pCDI was added and the blend was homogenized using a Speedmixer™ (Hauschild Engineering, Germany) for 30 seconds at 1600 rpm. Subsequently a sufficient amount of the reaction mixture to slightly overfill the 25 mm×12.5 mm×0.3 mm joint of the bond was put onto a wooden test bar (beech wood, 100 mm×25 mm×5 mm, Rochell GmbH, Germany) and a second wooden test bar was pressed onto the adhesive with low force. The joint was assembled by positioning the test bars with 12.5 mm overlap. The thickness of the adhesive layer was set at 0.3 mm using metal spacers. The test specimen was fixed in a mold by positioning a weight of 434 g on the joint and allowed to cure for 30 min in an oven at 130° C. After cooling to room temperature, the weight was removed and the samples were left at room temperature for at least a week prior to testing. The lap shear strength was determined at a crosshead speed of 5 mm/min and was calculated from the measured tensile force divided by the overlap area. For each series the average value of the lap shear strength was recorded, the experimental error typically amounted to 10%. The sample systems 4, 5 and 6 have also been tested using steel sheets (100 mm×25 mm×1 mm, Rochell GmbH, Germany). The SAFT (Shear Adhesion Failure Temperature) determination was carried out in analogy to ASTM D4498 using an air circulated oven. Prior to the determination the oven was preheated to 80° C. A lap shear test specimen was fixed at one end and held in a vertical position, the other—lower end was equipped with a weight of 100 g. In case the adhesive joint holds at 80° C. for 30 minutes the temperature was increased stepwise in 10° C. intervals keeping the sample for 30 minutes at each temperature till the bond fails. The highest temperature at which the bond remains stable for half an hour was recorded as SAFT. The mechanical and SAFT properties results were given in Table 3. The abbreviation n.d. stands for not determined.

TABLE-US-00002 TABLE 2 Formulations Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Polyesterol 1 93.03 80.65 76.93 72.73 68.97 57.15 [wt %] Catalyst 2 0.3 0.3 0.3 0.3 0.3 0.3 [wt %] pCDI [wt %] 6.97 19.35 23.07 27.27 31.03 42.85 Index 25 80 100 125 150 250 molar ratio of Outside Within range of 1:2 to 2:1 Outside carbodiimide range of range of groups in 1:2 to 2:1 1:2 to 2:1 pCDI to hydroxyl groups in polyesterol

TABLE-US-00003 TABLE 3 Mechanical properties Example Example Example Example Example Example Unit 2 3 4 5 6 7 Index 25 80 100 125 150 250 Wooden specimen Maximum Force [N] 510 1680 1370 1430 1390 1310 Lap shear [M Pa] 1.5 4.9 3.7 3.8 4.0 3.7 strength SAFT [° C.] <80 140 130 130 120 <80 Steel specimen Maximum force [N] n.d. n.d. 1010 1510 1730 n.d. Lap shear [MPa] n.d. n.d. 3.1 4.6 5.3 n.d. strength

[0225] It is apparent that for Examples 3-6, where the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in polyesterol is in the range of from 1:2 to 2:1, the mechanical properties are superior (especially SAFT) compared to Examples 2 and 7, where the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in polyesterol is outside of the range of from 1:2 to 2:1.

[0226] For the samples 3, 4, 5 and 6 the strength development of the joint of the bond as a function of time has been determined using wooden test bars. The sample preparation procedure for the lap shear test specimens was identical to that described above with this exception that the samples were not cured at 130° C. for half an hour. Instead the development of strength as a function of time of the fresh specimen was measured. The results were given in Table 4.

TABLE-US-00004 TABLE 4 Strength build-up for Examples 3, 4, 5 and 6 Unit Example 3 Example 4 Example 5 Example 6 Shear force [N] n.d. n.d. 9.07 8.16 after 1 min Shear force [N] 484 459 n.d. n.d. after 1.5 min Shear force [N] n.d. n.d. 555 435 after 2 min Shear force [N] 523 522 n.d. n.d. after 2.25 min Shear force [N] 545 561 624 524 after 3 min Shear force [N] 648 620 604 560 after 4 min

[0227] Example 3-6 show that the strength build-up of the adhesive bond occurs in a reasonable time span and that after about 4 minutes the strength has built up to about 30-40% of its final strength.

Comparative Examples 1-5—2K Adhesives

[0228] For the Comparative Examples wooden test bars were employed. The adhesive recipes are given in Table 5. The polyols employed in Comparative Example 1 to 3 were amorphous. In Comparative Example 4 straight polyesterol 1 was used to prepare the joint of the bond whereas in Comparative Example 5 straight pCDI was used. For the preparation of Comparative samples 4 and 5 polyesterol 1 and pCDI were preconditioned and applied at 90° C. The strength build-up of Comparative Examples 1-4 is given in Table 6. The lap shear strength and SAFT of the Comparative Examples 4 and 5 is given in Table 7.

TABLE-US-00005 TABLE 5 Formulations of the Comparative Examples 1-3 and Comparative Examples 4,5 respectively Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Diol [wt %] 7.44 — — — — Polyesterol 1 — — — 100 — [wt %] Polyetherol 1 — 20.00 — — — [wt %] Polyesterol 2 — — 22.33 — — [wt %] Catalyst 2 0.3 0.3 0.3 — — [wt %] pCDI [wt %] 92.56 80.00 77.67 — 100 Index 100 100 100 — — molar ratio of Within range of 1:2 to 2:1 — — carbodiimide groups in pCDI to hydroxyl groups in polyesterol

TABLE-US-00006 TABLE 6 Strength build-up for Comparative Examples 1 to 4 Comparative Example 4 (straight Comparative Comparative Comparative Polyesterol Unit Example 1 Example 2 Example 3 1) Shear [N] n.d. n.d. n.d. 317 force after 2 min Shear [N] n.d. n.d. n.d. 312 force after 4 min Shear [N] 2 n.d. 0 n.d. force after 5 min Shear [N] n.d. 0 n.d. n.d. force after 10 min Shear [N] n.d. n.d. 0 n.d. force after 15 min Shear [N] 2 n.d. n.d. n.d. force after 20 min Shear [N] 2 1 0 n.d. force after 45 min

TABLE-US-00007 TABLE 7 Mechanical properties of Comparative Examples 4 and 5 Comparative Comparative Example 4: Example 5 Unit Polyesterol 1 (straight pCDI) Maximum force [N] 400 250 Lap shear strength [MPa] 1.2 0.6 SAFT [° C.] <80 <80

[0229] It is apparent from the comparison of Examples 3-6 with Comparative Examples 1 to 5, that the specific combination of pCDI and a crystalline Polyesterpolyol, here Polyesterpolyol 1, gave superior properties, especially a clearly higher shear force when the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in the crystalline polyesterol was in the range of from 1:2 to 2:1. For polyesterols different from a crystalline polyesterol, even if the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in the polyesterol was in the range of from 1:2 to 2:1, the development of the shear force was inferior.

Example 8-11—1K Adhesives/Adhesive Films

[0230] Description of the 1K experimental procedure:

[0231] Polyesterol 1 and pCDI of Reference Example 1 were both conditioned at 90° C. Catalyst 2 was added to polyesterol 1 and premixed using a spatula. The pCDI was added and the blend was homogenized using a Speedmixer™ for 30 seconds at 1600 rpm. The mixture so obtained was drawn to a film with a thickness of 500 μm on a preheated Teflon® sheet that was fixed on a hot plate having a temperature of 130° C. using a doctor blade. The film was cured at this temperature (130° C.) for 30 min. Subsequently the Teflon sheet was taken from the hot plate and cooled to room temperature. The film could easily be removed from the Teflon sheet. A dry, tack-free and flexible film was obtained. A sample with dimensions of 25 mm×12.5 mm was cut from the film and positioned between two test wooden bars such that the overlap of the bars amounts to 12.5 mm. The assembly was clamped using a universal double clip and put in an air circulated oven having a temperature of 130° C. for 30 min. After cooling the clamp was removed. The test specimens were stored for at least two weeks in the lab prior to testing. The film formulations and the corresponding adhesive properties were given in Table 8 and 9, respectively.

TABLE-US-00008 TABLE 8 Formulations of 1K Examples 8 to 11 Example 8 Example 9 Example 10 Example 11 Polyesterol 1 93.03 76.93 68.97 57.15 [wt %] Catalyst 2 0.3 0.3 0.3 0.3 [wt %] pCDI [wt %] 6.97 23.07 31.03 42.85 Index 25 100 150 250 molar ratio of Outside range Within range of 1:2 to 2:1 Outside range carbodiimide of 1:2 to 2:1 of 1:2 to 2:1 groups in pCDI to hydroxyl groups in polyesterol

TABLE-US-00009 TABLE 9 Mechanical properties of 1K Examples 8 to 11 Example Example Example Example Unit 8 9 10 11 Index 25 100 150 250 Maximum force [N] n.d. 750 930 n.d. Lap shear strength [MPa] n.d. 1.9 2.7 n.d. SAFT test passed temperature [° C.] <80 170 160 80

[0232] It is apparent that for Examples 9 and 10, where the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in polyesterol is in the range of from 1:2 to 2:1, the mechanical properties are superior (especially SAFT) compared to Examples 8 and 11, where the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in polyesterol is outside of the range of from 1:2 to 2:1.

Example 12-14

[0233] The adhesive films of Examples 12-14 were prepared as described above for the Examples 8-11 with the difference that the temperature of drawing was at room temperature (temperature in the range of from 20 to 25° C.). Dry, tack-free and flexible film were obtained. The adhesive joint was prepared as described above for Example 8-11. The film formulations and the corresponding adhesive and SAFT properties were given in Table 10 and 11, respectively.

TABLE-US-00010 TABLE 10 Formulations of 1K Examples 12 to 14 Example 12 Example 13 Example 14 Polyesterol 1 [wt %] 76.93 72.73 68.97 Catalyst 2 [wt %] 0.3 0.3 0.3 pCDI [wt %] 23.07 27.27 31.03 Index 100 125 150 molar ratio of carbodiimide Within range of 1:2 to 2:1 groups in pCDI to hydroxyl groups in polyesterol

TABLE-US-00011 TABLE 11 Mechanical properties of 1K Examples 12 to 14 Unit Example 12 Example 13 Example 14 Index 100 125 150 Lap shear strength [MPa] 2.6 4.0 3.1 Maximum force [N] 900 1420 1050 SAFT [° C.] 150 150 150

[0234] It is apparent that for Examples 12-14, where first, the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in polyesterol is in the range of from 1:2 to 2:1 and second, the temperature at which the film was prepared was below the melting temperature of the polyesterol (drawing done at room temperature instead of 130° C.), further improved properties were obtained vis a vis experiment 9-11 where the film was prepared at a temperature above the melting temperature of the polyesterol.

Comparative Example 6-8—Comparative 1K Adhesives

[0235] The adhesive film recipes of the Comparative Examples 6-8 were given in Table 12. The polyols employed were amorphous. The adhesive films for the Comparative samples 6-8 were prepared according to the procedure described above for Example 8-11.

TABLE-US-00012 TABLE 12 Formulations of Comparative Examples 6 to 8 Comparative Comparative Comparative Example 6 Example 7 Example 8 Polyetherol 2 [wt %] 82.4 82.4 — Polyetherol 3 [wt %] — — 71.7 Catalyst 2 [wt %] 0.5 1.0 1.0 pCDI [wt %] 17.6 17.6 28.3 Index 100 100 100 molar ratio of Within range of 1:2 to 2:1 carbodiimide groups in pCDI to hydroxyl groups in polyol

[0236] The obtained films of Comparative Examples 6 to 8 were soft and sticky and not suitable for adhesive applications. When the drawing was performed at room temperature the films of the Examples 6-8 stayed liquid and could not be removed from the Teflon sheet.

[0237] Consequently, it is apparent that the use of a polyol different from polyesterol, even if the molar ratio of carbodiimide groups in pCDI to hydroxyl groups in the polyol is in the range of from 1:2 to 2:1, the mechanical properties are inferior (especially SAFT).

[0238] Overall, it is apparent from the Examples and Comparative Examples that the use of the specific combination of pCDI with crystalline polyesterol resulted in superior properties, for Example a SAFT of more than 80° C., preferably more than 100° C., more preferred more than 120° C. Second, the specific molar ratio of carbodiimide groups in pCDI to hydroxyl groups in the crystalline polyesterol in the range of from 1:2 to 2:1 clearly improved the mechanical properties of the thermosetting resin, which is also apparent, for Example, from the development of the shear force over time.

CITED LITERATURE

[0239] U.S. Pat. No. 5,079,326 A

[0240] Chemistry and technology of carbodiimides', Henri Ulrich, Wiley, Hoboken, USA, 2007

[0241] WO 2015/127041 A1

[0242] WO 2015/123416 A1

[0243] EP 0 381 324 A1

[0244] W. Adam and F. Yany, Analytical Chemistry, Vol. 49, No. 4, April 1977, 676

[0245] WO2016/026807 A1

[0246] WO 2015/127038 A1