Humidity-reactive hotmelt adhesive with increased open time

• US 8,357,453 B2
• Filed: 06/29/2007
• Issued: 01/22/2013
• Est. Priority Date: 06/30/2006
• Status: Expired due to Fees

• Current Assignee: Sika Technology Ag (Compagnie de Saint-Gobain SA)
• Original Assignee: Sika Technology Ag (Compagnie de Saint-Gobain SA)
• Inventors: Onuoha, Ukiwo
• Primary Examiner(s): Tran, Thao T.
• Application Number:
  US12/226,351
• Publication Number:
  US 20090110937A1
• Time in Patent Office: 2,034 Days
• Field of Search: 428/424.6, 428/425.1, 428/425.6, 428/425.8, 428/425.9, 428/423.1, 526/935, 525/452, 525/457, 524/500, 156/60
• US Class Current: 428/423.1
• CPC Class Codes: C08G 18/12 using two or more compounds having active hydrogen in the first polymerisation step
• CPC Class Codes: C08G 18/307 Atmospheric humidity
• CPC Class Codes: C08G 18/4812 Mixtures of polyetherdiols with polyetherpolyols having at least three hydroxy groups
• CPC Class Codes: C08G 2170/20 Compositions for hot melt adhesives
• CPC Class Codes: C08K 5/0016 Plasticisers
• CPC Class Codes: C08L 2666/20 Macromolecular compounds having nitrogen in the main chain according to C08L75/00 - C08L79/00; Derivatives thereof
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: C08L 75/06 from polyesters
• CPC Class Codes: C09J 175/08 from polyethers
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31573 Next to addition polymer of ethylenically unsaturated monomer
• CPC Class Codes: Y10T 428/3158 Halide monomer type [polyvinyl chloride, etc.]
• CPC Class Codes: Y10T 428/31591 Next to cellulosic
• CPC Class Codes: Y10T 428/31601 Quartz or glass
• CPC Class Codes: Y10T 428/31605 Next to free metal
• CPC Class Codes: Y10T 428/31609 Particulate metal or metal compound-containing

Abstract

The invention relates to moisture-reactive hotmelt adhesive compositions which comprise at least one polyurethane prepolymer P1 being liquid at room temperature containing isocyanate groups and also at least one linear polyurethane P2 being solid at room temperature which comprises polycaprolactone segments, contains hydroxyl groups and has a melt viscosity of 100-300 Pa·s at 170° C. The compositions are notable in particular for a prolonged open time.

Claims

1. Moisture-reactive hotmelt adhesive composition comprising

a) at least one polyurethane prepolymer P1 containing isocyanate groups and being liquid at room temperature, and

b) at least one linear polyurethane P2 being solid at room temperature which comprises polycaprolactone segments, contains hydroxyl groups and has a melt viscosity of 100-300 Pa·

s at 170°

C.

wherein

the prepolymer P1 is obtained through a reaction of at least one polyisocyanate with at least one polyol, the polyol being a polyoxyalkylene diol or a polyoxyalkylene triol having a degree of unsaturation of lower than 0.02 meq/g and a molecular weight of 1,000 to 30,000 g/mol.

2. Moisture-reactive hotmelt adhesive composition according to claim 1, wherein the linear polyurethane P2 being solid at room temperature comprising polycaprolactone segments is prepared from at least one polycaprolactone diol and at least one diisocyanate having a molecular weight of below 1000 g/mol.

3. Moisture-reactive hotmelt adhesive composition according to claim 2, wherein the polyurethane P2 being solid at room temperature comprising polycaprolactone segments is a polyurethane chain extended by alkylene diol and formed from polycaprolactone diol and a diisocyanate having a molecular weight of below 1000 g/mol.

4. Moisture-reactive hotmelt adhesive composition according to claim 1, wherein the linear polyurethane P2 being solid at room temperature comprising polycaprolactone segments has a melt flow index of 30-100 g/10 minutes.

5. Moisture-reactive hotmelt adhesive composition according to claim 1, wherein the linear polyurethane P2 being solid at room temperature comprising polycaprolactone segments has a melt viscosity of 100-150 Pa·

s at 170°

C.

6. Moisture-reactive hotmelt adhesive composition according to claim 1, wherein the linear polyurethane P2 being solid at room temperature comprising polycaprolactone segments has an OH number of less than 5 mg KOH/g.

7. Moisture-reactive hotmelt adhesive composition according to claim 1, wherein the fraction of the polyurethane P2 being solid at room temperature comprising polycaprolactone segments is 1.5%-10% by weight, based on the weight of the moisture-reactive hotmelt adhesive composition.

8. Moisture-reactive hotmelt adhesive composition according to claim 1, wherein the weight ratio of polyurethane prepolymer P1 being liquid at room temperature to solid polyurethane P2 is 15-4.

9. Moisture-reactive hotmelt adhesive composition according to claim 1, the composition further comprising at least one filler.

10. Moisture-reactive hotmelt adhesive composition according to claim 1, wherein the composition has an open time of 40 to 240 minutes.

11. Moisture-reactive hotmelt adhesive composition according to claim 1, the composition further comprising at least one organotin catalyst.

12. Method of adhesively bonding a first substrate S1 and a second substrate S2, comprising the steps of

(i) heating a moisture-reactive hotmelt adhesive composition according to claim 1 to a temperature of 40-120°

C.;

(ii) applying the heated moisture-reactive hotmelt adhesive composition to the surface of a first substrate S1;

(iii) joining, with contacting, the surface of the second substrate S2 to the hotmelt adhesive composition applied to the first substrate S1, within the open time; and

(iv) curing the hotmelt adhesive composition by means of water;

the first substrate S1 and the second substrate S2 being made from the same or different material.

13. Method according to claim 12, wherein the first substrate S1 and/or the second substrate S2 is made of glass, glass ceramic, PVC, metal, wood, coated metal or coated wood.

14. Method according to claim 12, wherein one of the two substrates S1 and S2 is glass or glass ceramic and the other is PVC or coated metal or coated wood.

15. Method according to claim 12, wherein the open time is between 40 and 240 minutes.

16. Adhesively bonded article adhesively bonded according to claim 12.

17. Adhesively bonded article according to claim 16, wherein the article is a glazing unit, a window or a door.

18. Adhesively bonded article according to claim 16, wherein the article is a built structure or a means of transport.

19. Method of adhesively bonding a first substrate S1 and a second substrate S2, comprising the steps of

(i) heating a moisture-reactive hotmelt adhesive composition according to claim 1 to a temperature of 40-120°

C.;

(ii′

) applying the heated moisture-reactive hotmelt adhesive composition in a gap which is formed at least partly by the surface of a first substrate S1 and the surface of a second substrate S2, and thus contacting the surface of the first substrate S1 and of the second substrate S2 by means of adhesive; and

(iv) curing the hotmelt adhesive composition by means of water;

the first substrate S1 and the second substrate S2 being made from the same or different material.