Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2002-04-08
2004-08-10
Cooney, Jr., John M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S172000
Reexamination Certificate
active
06774154
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates generally to semiflexible and flexible polyurethane foams having low fogging characteristics and improved physical properties, e.g., tensile strength.
2. Description of the Related Art
Semiflexible and flexible polyurethane foams employed in the production of shaped, molded and fabric laminated articles for use in the transportation industry, particularly the motor vehicle industry, are known. These polyurethane foams are prepared by reacting a polyesterol ether-containing compound with a polyisocyanate in the presence of a blowing agent. The polyesterol ether-containing compound is typically diethylene glycol adipate which may be formed by reacting adipic acid, diethylene glycol and a polyol such as trimethylolpropane to provide a degree of branching and cross-linking. The cyclic acid by-product of an adipic acid molecule with a diethylene glycol molecule is a 13 membered cyclic ester ring.
When forming motor vehicle components such as, for example, headliners, sun visors, etc., employing a polyurethane foam based on diethylene glycol adipate, the 13 membered ring volatilizes from the polyurethane foam and subsequently deposits on, for example, the car windows as an oily film. This is known as fogging. This, in turn, scatters light and results in poor lighting conditions for the driver.
In an effort to solve this problem, attempts have been made to produce polyesterol ether-containing polyols for use in the polyurethane foams by selecting the acid and/or polyol either to prevent the formation of cyclic by-products having rings with 12 to 14 atoms or to prevent the formation of any cyclic by-product. However, even though these polyurethane foams exhibit low fogging characteristics, the foams possess poor physical properties, e.g., tensile strength, tear strength, etc.
Accordingly, it would be desirable to provide semiflexible and flexible polyurethane foams which exhibits little to no fogging while also possessing excellent physical properties.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide semiflexible and flexible polyurethane foams exhibiting low fogging characteristics and having excellent physical properties making them suitable for motor vehicle applications.
It is another object of the present invention to provide a polyester polyol substantially free of any ether components from which the volatile products generating fogging have been substantially removed and which impart excellent physical properties, e.g., tensile strength, in semiflexible and flexible polyurethane foams.
Yet another object of the invention is to provide semiflexible and flexible polyurethane foams employed in the transportation industry made using the polyester polyols substantially free of any ether components having a reduced content of by-products that exhibit low fogging properties.
In keeping with these and other objects of the present invention, a semiflexible or flexible polyurethane foam with low fogging characteristics and improved physical properties is provided, wherein the foam is obtained from a polyurethane foam-forming reaction mixture containing as a polyester polyol for the foam a polyester polyol substantially free of any ether components which comprises:
(a) at least one polyfunctional carboxylic acid and/or carboxylic anhydride compound;
(b) at least one linear polyhydric alcohol; and
(c) at least one branched polyhydric alcohol wherein the reactants are selected such that they cannot combine to provide a cyclic ester comprising a 13 membered ring.
In a preferred embodiment of the present invention, a semiflexible or flexible polyurethane foam with low fogging characteristics and improved physical properties is provided, wherein the foam is obtained from a polyurethane foam-forming reaction mixture containing as a polyester polyol for the foam a polyester substantially free of any ether components which comprises:
(a) at least one polyfunctional carboxylic acid and/or carboxylic anhydride compound;
(b) at least one linear polyhydric alcohol having a functionality of two;
(c) at least one branched polyhydric alcohol having a functionality of two; and
(d) a polyol having a functionality of at least three wherein the reactants of the polyester polyol are selected such that they cannot combine to provide a cyclic ester comprising a 12 to 14 membered ring.
By utilizing polyester polyols substantially free of any ether components to produce semiflexible and flexible polyurethane foams, the fogging characteristics of the foams are significantly reduced while improving the foam's physical properties making them particularly suitable for use in the interiors of motor vehicles.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides semiflexible and flexible in polyurethane foams obtained from a polyurethane foam-forming reaction mixture containing at least a polyester polyol substantially free of any ether components and an organic isocyanate.
The starting polyester polyols for use in the polyurethane foam-forming reaction mixture to produce the polyurethane foams of the present invention are substantially free of any ether components. Accordingly, the starting polyester polyols are formed from at least (a) a polyfunctional carboxylic acid and/or carboxylic acid; (b) a linear polyhydric alcohol; and (c) a branched polyhydric alcohol and, optionally, a branched polyol having a functionality of at least three wherein the reactants are selected such that they cannot combine to provide a cyclic ester comprising a 12 to 14 membered ring. As one skilled in the art will readily appreciate, the formation of a cyclic ester from polyester polyols is to a large extent the cause of the fogging effect in flexible polyurethane foams. Thus, by reducing or eliminating the formation of a cyclic ester from the polyester polyol before the polyurethane foam is formed, the fogging characteristics of the foam is significantly reduced. Accordingly, it is particularly advantageous to provide a starting polyester polyol wherein the reactants are selected such that they cannot combine to provide a cyclic ester comprising a 12 to 14 membered ring and most preferably not forming a cyclic ester comprising an 11 to 15 membered ring.
The expression “polyester polyol substantially free of any ether components” as used herein shall be understood to mean a polyester polyol formed in the presence of little to no ether compounds. In this manner, the amount of any ether compounds, if present, in the polyester polyol must not cause any fogging or reduce the physical properties to a level considered unacceptable when the polyester polyol is employed in a semiflexible or flexible foam. Accordingly, this is achieved when the ether compound(s) are present in the polyester polyol in minor amounts, e.g., up to about 15 weight percent, preferably up to about 5 weight percent and most preferably 0 weight percent.
In accordance with the present invention, the first component of the polyester polyol is at least one polyfunctional carboxylic acid and/or carboxylic anhydride. Suitable polyfunctional carboxylic acids and carboxylic anhydrides for use herein include, but are not limited to, oxalic acid, malonic acid, succinic acid, gluaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isopthalic acid, nonamethylenedicarboxylic acid, decamethylenedicarboxylic acid, undecamethylenedicarboxylic acid, dodecamethylenedicarboxylic acid, tridecamethylenedicarboxylic acid, tetradecamethylenedicarboxylic acid, pentadecamethylenedicarboxylic acid, hexadecamethylenedicarboxylic acid, heptadecamethylenedicarboxylic acid, octadecamethylenedicarboxylic acid, nonadecamethylenedicarboxylic acid, eicosamethylenedicarboxylic acid, heneicosamethylenedicarboxylic acid docosamethylenedicarboxylic acid, tetracosamethylenedicarboxylic acid, octacosamethylenedicarboxylic acid, dotriacontamethylenedicarboxylic acid, phthalicanhydride and the like. The polyfunctional carboxylic acid(s) and/or carboxyl
Cooney Jr. John M.
Crompton Corporation
Dilworth Michael P.
LandOfFree
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