Polyurethane adhesive for windshield applications

• US 20030070741A1
• Filed: 05/15/2002
• Published: 04/17/2003
• Est. Priority Date: 05/15/2001
• Status: Active Grant

• Current Assignee: Sika Technology Ag (Compagnie De Saint-Gobain S.A.)
• Original Assignee: Sika Technology Ag (Compagnie De Saint-Gobain S.A.)
• Inventors: Rosenberg, Steven A., Blank, Norman, Yao, Hong, Bove, Thomas, Tschan, Hans Peter, Maurik, Adrian Van
• Granted Patent: US 7,226,523 B2
• Time in Patent Office: Days
• US Class Current: 156/108
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/12 using two or more compounds having active hydrogen in the first polymerisation step
• CPC Class Codes: C08G 18/289 containing silicon
• CPC Class Codes: C08G 18/307 Atmospheric humidity
• CPC Class Codes: C09J 175/04 Polyurethanes

Abstract

A polyurethane adhesive which is useful in bonding porous and non-porous surfaces is provided. The adhesive is especially useful in bonding windshield glass into automotive frames under a variety of environmental conditions, particularly in after market windshield replacement applications. The polyurethane includes at least one urethane prepolymer which is based on at least one thermoplastic polyol. In one embodiment, the urethane prepolymer may be formed from one or more polyisocyanates, one or more polyetherpolyols and one or more thermoplastic polyesterpolyols, wherein the prepolymer has a free isocyanate content of from about 0.6 to about 3.5 % by weight, based on the weight of the polyurethane. In another embodiment, a one-part adhesive composition is provided which includes an isocyanate-functional and thermoplastic polyurethane prepolymer having a free isocyanate content of from about 0.6 to about 3.5 % by weight, based on the weight of the polyurethane, and a combination of several catalysts which are capable of catalyzing the reaction of isocyanate moieties with isocyanate-reactive moieties while providing less temperature dependent catalyzing of the reaction between isocyanate moieties and water. Also provided is a process for bonding two or more substrates together utilizing the polyurethane adhesive. In automotive windshield replacement applications, the polyurethane adhesive allows for a sufficient working time and development of green strength to provide a safe drive-away time within 1 hour at a temperature from about 0 to about 100° C.

Claims

1. A process for bonding two or more substrate materials together comprising

a) contacting an adhesive composition comprising at least one urethane prepolymer formed from a reaction product comprising:

i) one or more polyisocyanates;

ii) one or more liquid polyetherpolyols; and

iii) one or more thermoplastic polyesterpolyols;

wherein the urethane prepolymer has a free isocyanate content of from about 0.6 to about 3.5% by weight, based on the weight of the polyurethane,

with at least one of the substrates;

b) contacting the substrates together, before the applied adhesive cures, along the portion of the substrate(s) to which the adhesive has been applied; and

c) allowing the adhesive to cure and bond the substrates together.

2. A process according to claim 1, wherein said one or more polyisocyanates comprises one or more diisocyanates.

3. A process according to claim 1, wherein said one or more liquid polyetherpolyols comprises an ethylene oxide end capped triol and/or a propylene oxide end capped triol.

4. A process according to claim 1, wherein said one or more liquid polyetherpolyols comprises an ethylene oxide end capped triol having a weight average molecular weight of about 4500 to about 5000.

5. A process according to claim 1, wherein said one or more liquid polyetherpolyols comprises a propylene oxide end capped triol having a weight average molecular weight of from about 150 to about 250.

6. A process according to claim 1, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol.

7. A process according to claim 1, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol having a weight average molecular weight of about 3500 to about 4500.

8. A process according to claim 1, wherein said urethane prepolymer has a free isocyanate content of from about 0.9 to about 2.5% by weight, based on the weight of the polyurethane.

9. A process according to claim 1, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second.

10. A process according to claim 1, wherein said polyurethane adhesive is suitable as an automotive windshield repair adhesive for bonding a windshield to the body of an automobile.

11. A process according to claim 10, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of one hour or less from application of the adhesive to the windshield and/or automobile body.

12. A process according to claim 10, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of 30 minutes or less from application of the adhesive to the windshield and/or automobile body.

13. A process according to claim 10, wherein said polyurethane adhesive provides a working time of about 6 to about 15 minutes.

14. A process according to claim 1, wherein said polyurethane adhesive has a compression force of less than about 0.18 MPa when measured at 5°

C.

15. A process according to claim 1, wherein said polyurethane adhesive has a compression force of less than about 0.1 MPa when measured at 5°

C.

16. A process according to claim 1, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second and a compression force of less than about 0.1 MPa when measured at 5°

C.

17. A process for bonding two or more substrate materials together comprising

a) contacting an adhesive composition comprising at least one urethane prepolymer formed from a reaction product comprising:

i) one or more polyisocyanates;

ii) two or more liquid polyetherpolyols; and

iii) two or more thermoplastic polyesterpolyols;

wherein the urethane prepolymer has a free isocyanate content of from about 0.6 to about 3.5% by weight, based on the weight of the polyurethane,

with at least one of the substrates;

b) contacting the substrates together, before the applied adhesive cures, along the portion of the substrate(s) to which the adhesive has been applied; and

c) allowing the adhesive to cure and bond the substrates together.

18. A process according to claim 17, wherein said one or more polyisocyanates comprises one or more diisocyanates.

19. A process according to claim 17, wherein said two or more liquid polyetherpolyols comprises an ethylene oxide end capped triol and/or a propylene oxide end capped triol.

20. A process according to claim 17, wherein said two or more liquid polyetherpolyols comprises an ethylene oxide end capped triol having a weight average molecular weight of about 4500 to about 5000.

21. A process according to claim 17, wherein said two or more liquid polyetherpolyols comprises a propylene oxide end capped triol having a weight average molecular weight of from about 150 to about 250.

22. A process according to claim 17, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol.

23. A process according to claim 17, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol having a weight average molecular weight of about 3500 to about 4500.

24. A process according to claim 17, wherein said urethane prepolymer has a free isocyanate content of from about 0.9 to about 2.5% by weight, based on the weight of the polyurethane.

25. A process according to claim 17, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second.

26. A process according to claim 17, wherein said polyurethane adhesive is suitable as an automotive windshield repair adhesive for bonding a windshield to the body of an automobile.

27. A process according to claim 26, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of one hour or less from application of the adhesive to the windshield and/or automobile body.

28. A process according to claim 26, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of 30 minutes or less from application of the adhesive to the windshield and/or automobile body.

29. A process according to claim 26, wherein said polyurethane adhesive provides a working time of about 6 to about 15 minutes.

30. A process according to claim 17, wherein said polyurethane adhesive has a compression force of less than about 0.18 MPa when measured at 5°

C.

31. A process according to claim 17, wherein said polyurethane adhesive has a compression force of less than about 0.1 MPa when measured at 5°

C.

32. A process according to claim 17, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second and a compression force of less than about 0.1 MPa when measured at 5°

C.

33. A polyurethane adhesive comprising at least one urethane prepolymer formed from a reaction product comprising:

i) one or more polyisocyanates;

ii) one or more liquid polyetherpolyols; and

iii) one or more thermoplastic polyesterpolyols;

wherein the urethane prepolymer has a free isocyanate content of from about 0.6 to about 3.5% by weight, based on the weight of the polyurethane.

34. A polyurethane adhesive according to claim 33, wherein said one or more polyisocyanates comprises one or more diisocyanates.

35. A polyurethane adhesive according to claim 33, wherein said one or more liquid polyetherpolyols comprises an ethylene oxide end capped triol and/or a propylene oxide end capped triol.

36. A polyurethane adhesive according to claim 33, wherein said one or more liquid polyetherpolyols comprises an ethylene oxide end capped triol having a weight average molecular weight of about 4500 to about 5000.

37. A polyurethane adhesive according to claim 33, wherein said one or more liquid polyetherpolyols comprises a propylene oxide end capped triol having a weight average molecular weight of from about 150 to about 250.

38. A process according to claim 33, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol.

39. A process according to claim 33, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol having a weight average molecular weight of about 3500 to about 4500.

40. A polyurethane adhesive according to claim 33, wherein said urethane prepolymer has a free isocyanate content of from about 0.9 to about 2.5% by weight, based on the weight of the polyurethane.

41. A polyurethane adhesive according to claim 33, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second.

42. A polyurethane adhesive according to claim 33, wherein said polyurethane adhesive is suitable as an automotive windshield repair adhesive for bonding a windshield to the body of an automobile.

43. A polyurethane adhesive according to claim 42, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of one hour or less from application of the adhesive to the windshield and/or automobile body.

44. A polyurethane adhesive according to claim 42, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of 30 minutes or less from application of the adhesive to the windshield and/or automobile body.

45. A polyurethane adhesive according to claim 42, wherein said polyurethane adhesive provides a working time of about 6 to about 15 minutes.

46. A process according to claim 33, wherein said polyurethane adhesive has a compression force of less than about 0.18 MPa when measured at 5°

C.

47. A process according to claim 33, wherein said polyurethane adhesive has a compression force of less than about 0.1 MPa when measured at 5°

C.

48. A process according to claim 33, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second and a compression force of less than about 0.1 MPa when measured at 5°

C.

49. A polyurethane adhesive comprising at least one urethane prepolymer formed from a reaction product comprising:

i) one or more polyisocyanates;

ii) two or more liquid polyetherpolyols; and

iii) two or more thermoplastic polyesterpolyols;

wherein the urethane prepolymer has a free isocyanate content of from about 0.6 to about 3.5% by weight, based on the weight of the polyurethane.

50. A polyurethane adhesive according to claim 49, wherein said one or more polyisocyanates comprises one or more diisocyanates.

51. A polyurethane adhesive according to claim 49, wherein said one or more liquid polyetherpolyols comprises an ethylene oxide end capped triol and/or a propylene oxide end capped triol.

52. A polyurethane adhesive according to claim 49, wherein said one or more liquid polyetherpolyols comprises an ethylene oxide end capped triol having a weight average molecular weight of about 4500 to about 5000.

53. A polyurethane adhesive according to claim 49, wherein said one or more liquid polyetherpolyols comprises a propylene oxide end capped triol having a weight average molecular weight of from about 150 to about 250.

54. A process according to claim 49, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol.

55. A process according to claim 49, wherein said one or more liquid polyetherpolyols comprises polypropylene glycol having a weight average molecular weight of about 3500 to about 4500.

56. A polyurethane adhesive according to claim 49, wherein said urethane prepolymer has a free isocyanate content of from about 0.9 to about 2.5% by weight, based on the weight of the polyurethane.

57. A polyurethane adhesive according to claim 49, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second.

58. A polyurethane adhesive according to claim 49, wherein said polyurethane adhesive is suitable as an automotive windshield repair adhesive for bonding a windshield to the body of an automobile.

59. A polyurethane adhesive according to claim 58, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of one hour or less from application of the adhesive to the windshield and/or automobile body.

60. A polyurethane adhesive according to claim 58, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of 30 minutes or less from application of the adhesive to the windshield and/or automobile body.

61. A polyurethane adhesive according to claim 58, wherein said polyurethane adhesive provides a working time of about 6 to about 15 minutes.

62. A process according to claim 49, wherein said polyurethane adhesive has a compression force of less than about 0.18 MPa when measured at 5°

C.

63. A process according to claim 49, wherein said polyurethane adhesive has a compression force of less than about 0.1 MPa when measured at 5°

C.

64. A process according to claim 49, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second and a compression force of less than about 0.1 MPa when measured at 5°

C.

65. A one-part polyurethane adhesive composition comprising

i) an isocyanate-functional and thermoplastic polyurethane prepolymer having a free isocyanate content of from about 0.6 to about 3.5% by weight;

and

ii) one or more catalysts which are capable of catalyzing the reaction of isocyanate moieties with isocyanate-reactive moieties while providing less temperature dependent catalyzing of the reaction between isocyanate moieties and water.

66. A one-part polyurethane adhesive composition according to claim 65, wherein said polyurethane prepolymer has a free isocyanate content of from about 0.9 to about 2.5% by weight.

67. A one-part polyurethane adhesive composition according to claim 65, wherein said combination of catalysts comprises one or more tin compound catalysts and/or one or more amine-containing catalysts.

68. A one-part polyurethane adhesive composition according to claim 65, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second.

69. A one-part polyurethane adhesive composition according to claim 65, wherein said polyurethane adhesive is suitable as an automotive windshield repair adhesive for bonding a windshield to the body of an automobile.

70. A one-part polyurethane adhesive composition according to claim 69, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of one hour or less from application of the adhesive to the windshield and/or automobile body.

71. A polyurethane adhesive according to claim 69, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of 30 minutes or less from application of the adhesive to the windshield and/or automobile body.

72. A polyurethane adhesive according to claim 69, wherein said polyurethane adhesive provides a working time of about 6 to about 15 minutes.

73. A process according to claim 65, wherein said polyurethane adhesive has a compression force of less than about 0.18 MPa when measured at 5°

C.

74. A process according to claim 65, wherein said polyurethane adhesive has a compression force of less than about 0.1 MPa when measured at 5°

C.

75. A process according to claim 65, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second and a compression force of less than about 0.1 MPa when measured at 5°

C.

76. A one-part polyurethane adhesive composition comprising

i) an isocyanate-functional and thermoplastic polyurethane prepolymer having a free isocyanate content of from about 0.6 to about 3.5% by weight;

and

ii) a combination of catalysts which are capable of catalyzing the reaction of isocyanate moieties with isocyanate-reactive moieties while providing less temperature dependent catalyzing of the reaction between isocyanate moieties and water.

77. A one-part polyurethane adhesive composition according to claim 76, wherein said polyurethane prepolymer has a free isocyanate content of from about 0.9 to about 2.5% by weight.

78. A one-part polyurethane adhesive composition according to claim 76, wherein said combination of catalysts comprises one or more tin compound catalysts and/or one or more amine-containing catalysts.

79. A one-part polyurethane adhesive composition according to claim 76, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second.

80. A one-part polyurethane adhesive composition according to claim 76, wherein said polyurethane adhesive is suitable as an automotive windshield repair adhesive for bonding a windshield to the body of an automobile.

81. A one-part polyurethane adhesive composition according to claim 80, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of one hour or less from application of the adhesive to the windshield and/or automobile body.

82. A polyurethane adhesive according to claim 80, wherein said polyurethane adhesive provides a safe drive-away time according to U.S. Federal Motor Vehicle Safety Standards of 30 minutes or less from application of the adhesive to the windshield and/or automobile body.

83. A polyurethane adhesive according to claim 80, wherein said polyurethane adhesive provides a working time of about 6 to about 15 minutes.

84. A process according to claim 76, wherein said polyurethane adhesive has a compression force of less than about 0.18 MPa when measured at 5°

C.

85. A process according to claim 76, wherein said polyurethane adhesive has a compression force of less than about 0.1 MPa when measured at 5°

C.

86. A process according to claim 76, wherein said polyurethane adhesive has a tensile strength of 1.0 MPa or greater when measured at a strain rate of 1 meter/second and a compression force of less than about 0.1 MPa when measured at 5°

C.