Reactive polyurethane hot melt adhesives containing fillers

Patent metadata

Field	Value
Publication number	US-11091677-B2
Application number	US-201816032543-A
Country	US
Kind code	B2
Filing date	Jul 11, 2018
Priority date	Jan 13, 2016
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

The present invention relates to a reactive polyurethane (PUR) hot-melt adhesive, in particular a moisture cross-linking 1K-PUR hot-melt adhesive, wherein the PUR adhesive contains neutralized hollow glass spheres as fillers. The invention also relates to the use of said adhesive for adhesively bonding substrates.

First claim

The invention claimed is:

1. A reactive polyurethane-based hot-melt adhesive composition containing, based on the total weight of the adhesive composition, from 1 to <30 wt. % of at least one solid particulate filler, wherein the at least one filler comprises neutralized hollow glass spheres, the hollow glass spheres, as a 5 wt. % dispersion in water at 20° C., having a pH of 6 to 9.

2. The hot-melt adhesive composition according to claim 1 , containing, based on the total weight of the adhesive composition, from 1 to <10 wt. % of neutralized hollow glass spheres.

3. The hot-melt adhesive composition according to claim 1 , containing, based on the total weight of the adhesive composition, from 2 to 6 wt. % of neutralized hollow glass spheres.

4. The hot-melt adhesive composition according to claim 1 , wherein the hollow glass spheres, as a 5 wt. % dispersion in water at 20° C., have a pH of from 6 to 8.

5. The hot-melt adhesive composition according to claim 1 , wherein the hollow glass spheres, as a 5 wt. % dispersion in water at 20° C., have a pH of from 6.5 to 7.5.

6. The hot-melt adhesive composition according to claim 1 , wherein the at least one filler has an average particle size d 50 of from 5 to 50 μm.

7. The hot-melt adhesive composition according to claim 1 , wherein the hot-melt adhesive composition contains at least one NCO-terminated polyurethane prepolymer.

8. The hot-melt adhesive composition according to claim 1 , wherein the hot-melt adhesive composition contains at least one NCO-terminated polyurethane prepolymer in an amount of from 20 to 95 wt. % based on the total weight of the hot-melt adhesive composition.

9. The hot-melt adhesive composition according to claim 1 , comprising an MDI-terminated polyurethane prepolymer reaction product of a polyester polyol mixture and MDI.

10. The hot-melt adhesive composition according to claim 1 , wherein the hot-melt adhesive is a moisture-curing 1K polyurethane hot-melt adhesive.

11. The hot-melt adhesive composition according to claim 1 , wherein the composition further contains at least one thermoplastic polyester in an amount of from 3 to 35 wt. %, based on the total weight of the hot-melt adhesive composition.

12. The hot-melt adhesive composition according to claim 1 , wherein the composition further contains at least one thermoplastic polyester, in an amount of from 5 to 25 wt. %, based on the total weight of the hot-melt adhesive composition.

13. The hot-melt adhesive composition according to claim 1 , wherein the hot-melt adhesive composition:
(a) has a viscosity of from 2,000 to 60,000 mPas determined according to DIN EN ISO 2555:2000-01 (Brookfield viscometer RV DV-II, spindle no. 27, 130° C.; 5 rpm); and/or
(b) has an NCO-content of from 0.25 to 4 wt. %; and/or
(c) has a density of ≤1.5 g/cm 3 .

14. The hot-melt adhesive composition according to claim 1 , wherein the hot-melt adhesive composition has a density of 0.9 to 1.1 g/cm 3 .

15. The hot-melt adhesive composition according to claim 1 , wherein the hot-melt adhesive composition has an increase in viscosity after 16 h at 130° C. of no more than 400%.

16. The hot-melt adhesive composition according to claim 1 , wherein the hot-melt adhesive composition has an increase in viscosity after 16 h at 130° C. of no more than 250%.

17. The hot-melt adhesive composition according to claim 1 , wherein:
(a) the composition further contains one or more additives selected from tackifying resin, tackifier, adhesion promoter, crosslinking agent, viscosity regulator, pigment, plasticizer, stabilizer, catalyst, wax or antioxidant; and/or
(b) the composition is substantially free of organic solvent.

18. Cured reaction products of the hot-melt adhesive composition according to claim 1 for adhesively bonding two or more substrates.

19. A substrate bonded to cured reaction products of the hot-melt adhesive composition according to claim 1 .

20. A reactive polyurethane-based hot-melt adhesive composition comprising, based on the total weight of the adhesive composition, from 1 to <30 wt. % of neutralized hollow glass spheres, wherein the hollow glass spheres, as a 5 wt. % dispersion in water at 20° C., have a pH of less than 9.0.

Assignees

• Henkel Ag & Co Kgaa

Inventors

• Franken Uwe
• Jonscher Karin

Classifications

• C09J175/06

  from polyesters · CPC title

• C08G2170/20

  Compositions for hot melt adhesives · CPC title

• C08G18/4238

  derived from dicarboxylic acids and dialcohols · CPC title

• C08G18/4211

  derived from aromatic dicarboxylic acids and dialcohols · CPC title

• C08G18/4202 Primary

  Two or more polyesters of different physical or chemical nature (C08G18/44 takes precedence) · CPC title