Polyurethane sealant compositions

• US 5,852,137 A
• Filed: 01/29/1997
• Issued: 12/22/1998
• Est. Priority Date: 01/29/1997
• Status: Expired due to Term

• Current Assignee: Essex Specialty Products Incorporated
• Original Assignee: Essex Specialty Products Incorporated
• Inventors: Mahdi, Syed Z., Hsieh, Harry W.
• Primary Examiner(s): Short, Patricia A.
• Application Number:
  US08/790,635
• Time in Patent Office: 692 Days
• Field of Search: 525/453, 525/457, 525/458, 528/18, 528/14, 528/20, 528/21, 528/28
• US Class Current: 525/458
• 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 18/16 Catalysts catalysts in general B01J
• CPC Class Codes: C08G 18/161 containing two or more components to be covered by at least two of the groups C08G18/166, C08G18/18 or C08G18/22
• CPC Class Codes: C08G 18/163 covered by C08G18/18 and C08G18/22
• CPC Class Codes: C08G 18/18 containing secondary or tertiary amines or salts thereof
• CPC Class Codes: C08G 18/1875 containing ammonium salts or mixtures of secondary of tertiary amines and acids
• CPC Class Codes: C08G 18/289 containing silicon
• 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 18/73 acyclic
• CPC Class Codes: C08G 18/792 formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
• CPC Class Codes: C08G 2190/00 Compositions for sealing or packing joints

Abstract

In one aspect, this invention is a polyurethane sealant composition comprising (1) a urethane prepolymer having an isocyanate functionality of at least about 2.0 and a weight average molecular weight of at least about 2,000; and (2) a catalytic amount of (a) a substantially active hydrogen free glycol acid salt of a tertiary amine and an organo metallic compound, (b) a mixture of a substantially active hydrogen free glycol acid salt of a tertiary amine and an organo metallic compound and a second organometallic compound, or (c) a mixture of an organometallic compound with dimorpholinodialkyl ether or an dialkylmorpholinodialkyl ether. In another embodiment, the polyurethane sealant composition further comprises (A) a silane, or (B) an adduct of an isocyanate reactive silane and a polyisocyanate, (C) the reaction product of an isocyanate reactive silane or an adduct of an isocyanate reactive silane and a polyisocyanate with a polyisocyanate and an active hydrogen containing compound or a polyurethane prepolymer which has free isocyanate moieties; which reaction product has an average of at least one silane group and at least one isocyanate group per molecule. In another embodiment the invention is a method for bonding glass to a substrate which comprises contacting a sealant according to the invention with glass and another substrate with the sealant disposed between the glass and substrate and thereafter allowing the sealant to cure so as to bind the glass to the substrate. The sealant composition of the invention is useful in bonding glass substrates to metal plastic, fiberglass or composite substrates, which may or may not be painted. It has been discovered to give unexpectedly high lap shear strength when no primer compositions have previously been applied to the painted plastic, metal, fiberglass or composite substrate.

Claims

1. A sealant composition comprising (1) a urethane prepolymer having an isocyanate functionality of at least about 2.0 and a weight average molecular weight of at least about 2,000;

(2) a catalytic amount of a substantially active hydrogen free glycol acid salt of a tertiary amine and an organo metallic compound, and (3) (A) a silane, (B) an adduct of an isocyanate reactive silane and a polyisocyanate, or (C) the reaction product of (i) (a) an isocyanate reactive silane or (b) an adduct of an isocyanate reactive silane and a polyisocyanate with (ii) (a) a polyisocyanate and an active hydrogen containing compound or (b) a polyurethane prepolymer which has free isocyanate moieties, wherein the reaction product has an average of at least one silane group and at least one isocyanate group per molecule.

2. The polyurethane sealant composition of claim 1 wherein the substantially active hydrogen free glycol acid salt of tertiary amine and the organometallic compound is the reaction product of a polyisocyanate and a glycol acid salt of tertiary amine and an organometallic compound.

3. The sealant composition of claim 1 wherein the tertiary amine has a pH of about 8 to about 10.

4. The sealant composition of claim 1 wherein the isocyanate content of the prepolymer is in the range of from about 1.5 percent to about 5.0 percent.

5. The sealant according to claim 1 wherein the tertairy amine is triethylene diamine or 1,8 diazabicycloundecene.

6. The sealant composition of claim 1 wherein the catalyst further comprises a second organo metallic compound, a dimorpholino dialkyl ether, a di((dialkylmorpholino)alkyl) ether or a mixture thereof.

7. The sealant composition of claim 6 wherein the second organo metallic compound is a dialkyl tin dicarboxylate.

8. The sealant composition of claim 7 wherein the dialkyl tin dicarboxylate corresponds to the formula (R² OC(O))₂ --Sn--(R³)₂ wherein R² and R³ are independently in each occurrence a C_1-10 alkyl.

9. The sealant according to claim 7 wherein the organometallic compound is 1, 1-dimethyltin dilaurate, 1,1-dibutyltin diacetate, 1,1-dimethyl dimaleate or a dialkyltin dimercaptide.