Adhesives based on carbodimide chemistry

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 2 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.

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 2 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.