Flexible Polyurethane Foams and Process for Producing Same
Publication Date: 2002-Aug-15
The IP.com Prior Art Database
AbstractThe instant invention relates to polyester polyol compositions which are suitable for use in the preparation of flexible polyurethane foams. The instant invention further relates to methods of producing such compositions, flexible foams produced from the compositions and methods of preparing foams utilizing such compositions. It has been surprisingly discovered that the all polyester polyol compositions of the instant invention produce flexible polyurethane foams in combination with various isocyanates, wherein the final foam possess many highly desirable properties, without the use of polyether polyols and/or other polyester polyols, such as aliphatic polyols. The inventive flexible polyurethane foams possess highly desirable softness properties without the use of decreased amounts of isocyanates. Further, the flexible polyester based foams are surprising resistant to hydrolysis, while at the same time possessing good structural integrity and excellent flame retardancy using conventional flame retardants. More specifically, the invention encompasses flexible polyester polyurethane foams which comprise the reaction product of a phthalate polyester polyol, an isocyanate, water, a urethane catalyst and a compatiblizing surfactant/emulsifier. The invention further encompasses methods of preparing the inventive foams. Other key terms the polyester polyol, phthalic anhydride, phthalic acid; alkylene groups, adipic acid-based polyester polyol.
Field of the Invention
The present invention relates to flexible polyurethane foams and polyester polyol compositions suitable for preparing such foams. The instant invention also relates to methods for preparing the phthalate polyester-based compositions and methods of producing flexible foams therefrom. Further, the invention relates to the use of such flexible foams as molded insulation and cushioning materials in a variety of end use applications. The phthalate polyester polyol-based polyurethane flexible foams of the instant invention exhibit surprising hydrolytic stability alone or in combination with conventional flame retardants, compared to conventional adipate ester-based materials and/or foams which contain adipic acid based polyols. Additionally, the inventive flexible foams possess desirable softness properties and are typically free of undesired holes. The inventive foams are typically open celled flexible foams.
Description of the Related Art
The field of polyurethane foams has grown dramatically over the last twenty years. This trend has been based primarily on innovations and improvements which have lead to enhanced foam physical properties, such as improved dimensional stability, optimized foam cell structure, controlled shrinkage characteristics, improved hydrolytic stability properties and improved flame retardation characteristics. As is well known to one skilled in the art, polyurethane foams are based on the reaction of a polyisocyanate with a polyether polyol, a polyester polyol or a mixture thereof.
Molded polyurethane foams may generally be poured in place, such as is done when producing a seat cushion or foam padding parts. Additionally, these materials may be poured into and used as insulation materials in water coolers or water heaters. Polyurethane foams have also been employed for a variety of pour-in-place insulation uses including, for example, refrigeration cabinets, doors and walls.
As is well known to one of ordinary skill in the art, polyether polyols may have a greater functionality than polyester polyols, and polyether polyol based foams are generally believed to be more resistant to hydrolysis, as compared to their polyester counterparts, based on the presence of hydrolyzable ester linkages in the polyester polyol. Further, those skilled in the art generally recognize that polyether-based polyurethane foams generally have poor flame retardant characteristics and are difficult to handle as compared to their polyester polyol based counterparts, because of their lower viscosity, i.e., they tend to splash as thin liquids when pouring in place or pouring into a mold. Splashing is undesirable, as it has a tendency to trap air in the foam-forming mixture, which in turn leads to the formation of air bubbles in the foaming mixture as it commences rising. These air bubbles cause holes ...