1. Field of the Invention
This invention relates to improved liquid polysulfide polymer based adhesive compositions containing novel adhesive additives. More particularly, this invention relates to improved liquid polysulfide polymer based adhesive compositions containing novel adhesive additives prepared by modifying polysulfide and polyester polymers with abietic acid and polysulfide polymers with epoxy groups.
2. Description of the Prior Art
Curable, liquid polysulfide polymer based sealant and caulking compositions have long been known in the art. They are based on curable, liquid, mercaptan terminated polysulfide polymers. The structure and preparation of these polythiopolymercaptan polymers are disclosed in U.S. Pat. No. 2,466,963. These liquid, mercaptan terminated polymers are used extensively in sealant and caulking compositions, especially in the building, automotive, and marine industries; for castings, e.g., solid rocket propellants; for leather and textile impregnating agents; for adhesives, coatings, etc. Because of the wide range of applications in which these polysulfide polymer based sealing and caulking compositions are used, they must be capable of bonding to various substrates, e.g., metal, aluminum, glass, concrete, wood, etc. However, the adhesive qualities of polysulfide polymers are such as to usually require the use of an adhesive additive in the polysulfide polymer based sealant composition in order to insure adequate bonding of the cured sealant to the substrate.
Adhesive additives of the prior art such as those of a phenolic nature provided only a polar, rather than a chemical, type bonding of the cured sealant to the substrate. Thus, sealant compositions containing phenolic type adhesive additives were found to be susceptible to attack by polar solvents such as water. The polar solvent tended to break down the polar bond thereby impairing the utility of the sealant composition. More recently, as disclosed in U.S. Pat. Nos. 3,297,473; 3,312,669, and 3,328,451, certain organo-silanes e.g., (mercapto alkyl amino alkyl alkoxyl silanes) have been proposed to overcome these problems. However, while the organo-silane adhesive additives have been found to protect the sealant composition bonds from attack by polar solvents, they do have certain disadvantages. Thus, the organo-silane adhesive additives are economically costly, somewhat deficient in storage stability, and exhibit erratic adhesion results with certain substrates, such as concrete.
The object of the present invention, therefore, is to provide a novel liquid polysulfide polymer based caulking or sealant composition which will allow for the attainment of a strong and lasting bonding of the sealant to the substrates to be treated therewith.
Another object of the present invention is to provide a novel liquid polysulfide polymer based caulking or sealant composition containing adhesive additives which are less costly, exhibit improved storage stability, and which exhibit more reproducible and uniform adhesion characteristics to a wider range of substrates.
Other objects of the invention will become apparent to those skilled in the art from a consideration of the following detailed description.