Structural polyurethane adhesive

Patent metadata

Field	Value
Publication number	US-9914862-B2
Application number	US-201414779847-A
Country	US
Kind code	B2
Filing date	May 14, 2014
Priority date	May 15, 2013
Publication date	Mar 13, 2018
Grant date	Mar 13, 2018

Abstract

The present invention relates to a two-component polyurethane adhesive consisting of a polyol component and a polyisocyanate component, wherein the polyol component comprises a triol with a molar mass of 1,000 to 10,000 g/mol, a diol having two primary hydroxy groups and a molar mass of 60 to 150 g/mol, a poly(trimethylene oxide) diol or a poly(tetramethylene oxide) diol with a molar mass of 200 to 3,000 g/mol and an aliphatic polyamine. The adhesive is characterized by high early strength, a low temperature dependence of the mechanical properties, good adhesion and the possibility of controlled thermally induced release of adhesion.

First claim

The invention claimed is:

1. A polyurethane adhesive comprising a polyol component K1 and a polyisocyanate component K2; wherein:
the polyol component K1 comprises:

at least one triol A1 with an average molar mass in a range of 1,000 to 10,000 g/mol;
at least one diol A2 having two primary hydroxy groups and a molar mass in a range of 60 to 150 g/mol;
at least one diol A3 with an average molar mass in a range of 200 to 3000 g/mol, which is either a poly(trimethylene oxide) diol or a poly(tetramethylene oxide) diol, and
at least one aliphatic polyamine PA with a molar mass in a range of 60 to 500 g/mol; and
the polyisocyanate component K2 comprises:

at least one polyisocyanate B1; and
at least one isocyanate group-containing polyurethane polymer B2 different from polyisocyanate B1 and obtained by reacting at least one polyisocyanate with at least one polyol;
wherein the triol A1, the diol A2 and the diol A3 are present in such a quantity that a weight ratio of (A1+A3)/A2 is in a range of 2.5:1 to 20:1, and a weight ratio of A1/A3 is in a range of 2:1 to 100:1.

2. The polyurethane adhesive according to claim 1 , wherein the triol A1 is a polyether triol.

3. The polyurethane adhesive according to claim 1 , wherein the triol A1 has primary hydroxy groups.

4. The polyurethane adhesive according to claim 1 , wherein the triol A1 has an average molar mass in a range of 3,000 to 8,000 g/mol.

5. The polyurethane adhesive according to claim 1 , wherein the diol A3 is a poly(trimethylene oxide) diol.

6. The polyurethane adhesive according to claim 1 , wherein the diol A3 is a poly(tetramethylene oxide) diol.

7. The polyurethane adhesive according to claim 1 , wherein the polyamine PA is selected from the group consisting of:
1,5-diamino-2-methylpentane, 2,2,4- and 2,4,4-trimethylhexamethylene diamine, 1,8-octanediamine, 1,10-decanediamine, 1,12-dodecane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 2- and 4-methyl-1,3-diaminocyclohexane and mixtures thereof, 1,3-bis-(aminomethyl)cyclohexane, 1,4-bis-(aminomethyl)cyclohexane, 2,5(2,6)-bis-(aminomethyl)-bicyclo[2.2.1]heptane, 3(4),8(9)-bis-(aminomethyl)-tricyclo[5.2.1.0 2,6 ]decane, bis-(2-aminoethyl) ether, 3,6-dioxaoctane-1,8-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxadecane-2,9-diamine, 4,9-dioxadodecane-1,12-diamine, 5,8-dioxadodecane-3,10-diamine, 1,3-bis-(aminomethyl)benzene and 1,4-bis-(aminomethyl)benzene.

8. The polyurethane adhesive according to claim 1 , wherein the polyisocyanate B1 is liquid at room temperature and is any liquid mixture of 4,4′-, 2,4′- and/or 2,2′-diphenylmethane diisocyanate (MDI) or a polymeric MDI.

9. The polyurethane adhesive according to claim 1 , wherein the isocyanate group-containing polyurethane polymer B2 is configured as a reaction of 4,4′-diphenylmethane diisocyanate with at least one polyol.

10. The polyurethane adhesive according to claim 1 , wherein a mixing ratio in volumes between the polyol component K1 and the polyisocyanate component K2 is in a range of 1:3 to 3:1.

11. A method for bonding a first substrate to a second substrate, comprising:
applying the polyurethane adhesive according to claim 1 to at least one substrate surface to be bonded;
fitting substrates to be bonded together within an open time; and
curing the polyurethane adhesive.

12. The method according to claim 11 , wherein one or both substrate(s) is/are a metal or a glass ceramic or a glass or a glass fiber-reinforced plastic or a carbon fiber-reinforced plastic or a thermoset derived from an epoxy compound.

13. An article formed from the method of bonding according to claim 11 .

14. A method for thermally-induced release of adhesion by thermal degradation comprising:
heating a cured polyurethane adhesive to a temperature of 120° C.-200° C. for 10-50 min; and
releasing the cured polyurethane adhesive, wherein the cured polyurethane adhesive prior to curing is according to claim 1 .

15. A method for bonding a first substrate to a second substrate, wherein at least the first substrate is a glass fiber-reinforced plastic or a carbon fiber-reinforced plastic or a thermoset derived from an epoxy compound or a glass-mineral fiber mat, the method including;
bonding the first substrate and the second substrate with a polyurethane adhesive according to claim 1 .

16. The polyurethane adhesive according to claim 1 , wherein the weight ratio of (A1+A3)/A2 is in a range of 3:1 to 15:1, and the weight ratio of A1/A3 is in a range of 3:1 to 75:1.

17. The polyurethane adhesive according to claim 1 , wherein the weight ratio of (A1+A3)/A2 is in a range of 4:1 to 10:1, and the weight ratio of A1/A3 is in a range of 4:1 to 50:1.

18. The polyurethane adhesive according to claim 1 , wherein a mixing ratio in volumes between the polyol component K1 and the polyisocyanate component K2 is in a range of 1:2 to 2:1.

19. The polyurethane adhesive according to claim 2 , wherein the diol A3 is a poly(trimethylene oxide) diol.

20. The polyurethane adhesive according to claim 19 , wherein the polyamine PA is selected from the group consisting of:
1,5-diamino-2-methylpentane, 2,2,4- and 2,4,4-trimethylhexamethylene diamine, 1,8-octanediamine, 1,10-decanediamine, 1,12-dodecane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 2- and 4-methyl-1,3-diaminocyclohexane and mixtures thereof, 1,3-bis-(aminomethyl)cyclohexane, 1,4-bis-(aminomethyl)cyclohexane, 2,5(2,6)-bis-(aminomethyl)-bicyclo[2.2.1]heptane, 3(4),8(9)-bis-(aminomethyl)-tricyclo[5.2.1.0 2,6 ]decane, bis-(2-aminoethyl) ether, 3,6-dioxaoctane-1,8-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxadecane-2,9-diamine, 4,9-dioxadodecane-1,12-diamine, 5,8-dioxadodecane-3,10-diamine, 1,3-bis-(aminomethyl)benzene and 1,4-bis-(aminomethyl)benzene.

21. A package containing two chambers separated from one another, one chamber comprising a polyol component K1 and the other chamber comprising a polyisocyanate component K2, wherein
the polyol component K1 comprises:

at least one triol A1 with an average molar mass in a range of 1,000 to 10,000 g/mol;
at least one diol A2 having two primary hydroxy groups and a molar mass in a range of 60 to 150 g/mol;
at least one diol A3 with an average molar mass in a range of 200 to 3000 g/mol, which is either a poly(trimethylene oxide) diol or a poly(tetramethylene oxide) diol, and at least one aliphatic polyamine PA with a molar mass in a range of 60 to 500 g/mol; and
the polyisocyanate component K2 comprises:

at least one polyisocyanate B1; and
at least one isocyanate group-containing polyurethane polymer B2 different from polyisocyanate B1 and obtained by reacting at least one polyisocyanate with at least one polyol;
wherein the triol A1, the diol A2 and the diol A3 are present in such a quantity that a weight ratio of (A1+A3)/A2 is in a range of 2.5:1 to 20:1, and a weight ratio of A1/A3 is in a range of 2:1 to 100:1.

22. A method for bonding a first substrate to a second substrate, comprising:
mixing the polyol component K1 and the polyisocyanate component K2 of the package of claim 21 to form a mixed polyurethane adhesive,
applying the mixed polyurethane adhesive to at least one substrate surface to be bonded;
fitting substrates to be bonded together within an open time; and
curing the polyurethane adhesive.

Assignees

• Sika Tech Ag

Inventors

• Kelch Steffen
• Roock Wolfgang
• Ittrich Florian

Classifications

• B32B37/12

  characterised by using adhesives · CPC title

• C08G18/2081

  containing at least two non-condensed heterocyclic rings · CPC title

• B32B2315/02

  Ceramics · CPC title

• B65D81/325

  Containers having parallel or coaxial compartments, provided with a piston or a movable bottom for discharging contents · CPC title

• C08G18/4854

  Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group · CPC title