POLYURETHANE SEALANT CONTAINING TRIALKYLOXYSILANE END GROUPS

• US 3,627,722 A
• Filed: 05/28/1970
• Issued: 12/14/1971
• Est. Priority Date: 05/28/1970
• Status: Expired due to Term

• Current Assignee: George M. Seiter
• Original Assignee: George M. Seiter
• Inventors: Seiter, George M.
• Primary Examiner(s): Czaja, Donald E.
• Assistant Examiner(s): Welsh, M. J.
• Application Number:
  US05/041,597
• Time in Patent Office: 565 Days
• Field of Search: 260/77.5A,77.5AP,77.5AM,75NA,37N
• US Class Current: 524/869
• 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 18/289 containing silicon
• CPC Class Codes: C09K 2200/023 Sulfur-containing compounds
• CPC Class Codes: C09K 2200/0239 Oxides, hydroxides, carbonates
• CPC Class Codes: C09K 2200/0243 Silica-rich compounds, e.g. silicates, cement, glass
• CPC Class Codes: C09K 2200/0247 Silica
• CPC Class Codes: C09K 3/1021 Polyurethanes or derivatives thereof
• CPC Class Codes: Y10T 428/31601 Quartz or glass
• CPC Class Codes: Y10T 428/31612 As silicone, silane or siloxane

Abstract

A polyurethane sealant composition containing terminal-NCO groups, at least 5 percent of the -NCO groups being end-blocked with -Si(OR)3 groups, where R is a lower alkyl. The terminal silane groups provide adhesion retention of the sealant to substrates such as metal or glass even after prolonged water immersion.

Claims

2. thereafter reacting said material with a silane of the formula HR1-R2-Si(OR)3 wherein R, R1, and R2 are as in claim 1, the proportions of said silane being such that at least about 5 percent of the -NCO groups of said -NCO terminated material are reActed with said silane.

3. A material according to claim 2 wherein the said ratio of equivalents ranges from 1.4:

1 to 3;

1.

4. A material according to claim 2 wherein said organic polyisocyanate is an aromatic diisocyanate and said active hydrogen-bearing compound is a polyalkyleneether glycol.

5. A material according to claim 2 wherein said silane is selected from the group consisting of an alkylaminoalkyltrialkoxysilane;

a mercaptoalkyltrialkoxysilane; and

wherein R and R2 are as defined in claim 2.

6. A material according to claim 1 wherein each R is a methyl group.

7. A sealant composition comprising a curable fluid organic material according to claim 1.

8. A sealant composition according to claim 7 wherein said composition contains a finely divided filler in an amount sufficient to form a thixotropic paste.

9. A sealant composition according to claim 8 wherein said filler comprises finely divided silica.

10. A sealant composition according to claim 1 wherein about 50 percent or less of said (a) and (b) groups in said material are said group (b).

11. A curable fluid -NCO-terminated polyurethane prepolymer suitable for use as a sealant, said prepolymer having an average molecular weight between about 200 and about 20,000, said prepolymer being prepared by:

12. A glass substrate coated with the material of claim 1.

13. A composition curable to a tough, flexible product, said composition comprising:

1 An -NCO terminated prepolymer having about 2 to about 8 -NCO groups per average molecular weight, said average molecular weight being between about 200 and about 20,000, said prepolymer having been derived from a reaction mixture comprising a compound having at least two active hydrogen-bearing groups, as determined by the Zerwitinoff test, and 1.05-6.0 equivalents, per equivalent of said active hydrogen bearing group, of an organic polyisocyanate;

2 Up to about 50 percent by weight of filler, and 3 Interacted with said prepolymer, at least about 0.7 weight percent and up to about 1.4 weight percent, based on the total of components (1)-(3), of a silane of the formula HR1-R2-Si(OR)3, where R is a lower alkyl group, where R3 is an alkyl, substituted alkyl, aryl, substituted aryl, or where R4 is an alkyl, substituted alkyl, aryl, or substituted aryl group, R2 is an alkylene group having two to 18 carbon atoms, R, R1, R2, R3, and R4 being free of active hydrogens, and H being an active hydrogen.

14. A glass substrate coated with the composition of claim 13.

15. A composition curable to a tough, flexible product, said composition comprising:

1 500-996 parts by weight of an -NCO terminated prepolymer having about 2 to about 8 -NCO groups per average molecular weight, said average molecular weight being between about 200 and about 20,000, said prepolymer having been derived from a reaction mixture comprising a compound having at least two active hydrogen-bearing groups, as determined by the Zerwitinoff test, and 1.05-6.0 equivalents, per equivalent of said active hydrogen-bearing group, of an organic polyisocyanate;

2 interacted therewith, 7-76.5 parts by weight of a silane of the formula HR1-R2-Si(OR)3, where R is a lower alkyl group, where R3 is an alkyl, substituted alkyl, aryl, substituted aryl, or where R4 is an alkyl, substituted alkyl, aryl, or substituted aryl group, R2 is an alkylene group having two to 18 carbon atoms, R, R1, R2, R3, and R4 being free of active hydrogens, and H being an active hydrogen.

16. A glass substrate coated with the composition of claim 15.

17. A composition according to claim 15 wherein said composition contains up to 950 parts by weight of a filler.