Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-05-02
2001-11-06
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S424000, C524S433000, C524S494000
Reexamination Certificate
active
06313207
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to filled polyols, filled polyurethanes and their method of manufacture.
BACKGROUND OF THE INVENTION
Reaction injection molding (“RIM”) is a well-known method for manufacture of molded polyurethane parts. In the RIM method, an isocyanate component is reacted with a polyol component that is filled with Barium Sulfate or other filler materials to produce a filled polyurethane elastomer. The filled polyurethanes may be used in numerous applications, including acoustical insulation for automotive vehicles. When used as acoustical insulation, the filled polyurethanes should have a specific gravity of at least about 1.5.
A long standing problem in achieving filled polyurethanes which have a specitic gravity of at least about 1.5 is that a polyol filled with a sufficient amount of filler to yield this specific gravity has a viscosity of more than 100,000 centipoise (“cps”). This renders use of the filled polyol impractical or impossible in RIM methods.
A need therefore exists for filled polyols which can be employed in RIM methods and which provide filled polyurethanes which have a specific gravity of at least about 1.5 and which have a viscosity less than about 100,000 centipoise at 25° C.
SUMMARY OF THE INVENTION
The invention relates to filled polyols having a specific gravity of at least about 1.5 and a viscosity at 25° C. of less than about 100,000 centipoise. The filled polyols can include at least one polyol of any of low molecular weight polyols, polytetramethylene glycols, midrange molecular weight triols and midrange molecular weight diols, and mixtures thereof, with a a powdered filler material. The filler material is present in an amount sufficient to achieve a specific gravity of at least about 1.5 and a viscosity at 25° C. of less than about 100,000 centipoise.
The invention further relates to a filled polyurethane that is the reaction product of the afore described filled polyol composition an aromatic isocyanate having a functionality of 2.0 or more, or an aliphatic isocyanate having a functionality of 2.0 or more.
The invention advantageously provides filled polyols which have viscosities less then about 100,000 centipoise and which can be used in RIM methods to produce filled polyurethanes.
The invention advantageously enables manufacture of filled polyurethanes which cure to a tack free state in approximately 15 sec. on an aluminum plate heated to 110 F. The specific gravity of filled polyurethanes produced in the invention may vary from about 1.5 to about 10, preferably about 1.6 to about 3, more preferably about 1.7 to about 2.0, most preferably about 1.8.
REFERENCES:
patent: 4582887 (1986-04-01), Dominguez et al.
patent: 5607998 (1997-03-01), Markusch et al.
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