Latent reactive adhesive preparations
The invention relates to the use of solid polycarbodiimide resins having a softening temperature of >+30° C. as cross-linking agents for adhesive dispersions polymers. The mixtures from at least one solid polycarbodiimide resin and at least one polymer dispersion are suitable for producing storage stable latent-reactive adhesive dispersions, latent-reactive adhesive layers, self-supporting latent reactive adhesive films or latent-reactive adhesive powders.
1 . A latently reactive, dispersion polymer-based preparation having a minimum film-forming temperature of ≤+23° C. and a glass transition temperature measured by DSC (heating rate 20 K/min) of ≤0° C. that can be crosslinked with carbodiimides and that comprises at least one polycarbodiimide having a glass transition temperature of at least +30° C. and an average functionality of at least 2, wherein the dispersion polymer is a semicrystalline polyurethane polymer or polyurethane-polyurea polymer.
2 . The preparation of claim 1 , which is an aqueous dispersion.
3 . The preparation of claim 1 , which is a pulverulent mixture.
4 . The preparation of claim 1 , which is a film.
5 . The preparation of claim 1 , wherein the polycarbodiimide has aliphatically or cycloaliphatically attached carbodiimide groups.
6 . The preparation of claim 1 , wherein the polycarbodiimide has a particle size dv(50)≤70 μm.
7 . The preparation of claim 6 , wherein the polycarbodiimide has a particle size dv(50)≤20 μm.
8 . The preparation of claim 7 , wherein the polycarbodiimide has a particle size dv(50)≤3.4 μm.
9 . The preparation of claim 1 , wherein the dispersion polymer comprises polycarbonate segments in the polyol component (A).
10 . A substrate coated with the preparation of claim 1 .
11 . A substrate coated with a latently reactive film obtained from the preparation of claim 1 .
12 . The substrate of claim 11 , wherein the substrate is bonded by thermally induced curing of the latent-reactive film.
13 . An adhesive comprising the latently reacative, dispersion polymer-based preparation of claim 1 .
14 . An adhesive comprising a latently reactive, dispersion polymer-based preparation having a minimum film-forming temperature of ≤+23° C. and a glass transition temperature measured by DSC (heating rate 20 K/min) of ≤0° C. that can be crosslinked with carbodiimides and that comprises at least one polycarbodiimide having a glass transition temperature of at least +30° C. and an average functionality of at least 2, wherein
the adhesive is a storage-stable, self-supporting latently reactive adhesive film, or
the adhesive is a storage-stable, self-supporting latently reactive adhesive powder.