Compositions – Compositions containing a single chemical reactant or plural... – Organic reactant
Reexamination Certificate
2000-06-14
2004-12-14
Sergent, Rabon (Department: 1711)
Compositions
Compositions containing a single chemical reactant or plural...
Organic reactant
C252S182210, C252S182220, C252S182250, C252S182260, C252S182270, C252S182290, C528S059000, C528S060000, C528S066000, C528S077000, C560S026000, C560S330000, C560S359000
Reexamination Certificate
active
06830705
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
Liquid stable MDI prepolymers and liquid stable curative systems suitable for room temperature casting which yield high performance urethane elastomers.
2. Prior Art
A search of the prior art showed many prepolymers and many curatives, none of which were specifically adapted to room temperature casting for the production of high-performance urethane elastomers, especially such elastomers which have remarkable low-shrink characteristics, wherein both the prepolymer and the curative are liquid or semi-liquid and stable at room temperature, and wherein the curing can also be effected at room temperature, and much less with systems which are totally free of TDI and which rely solely on MDI as the isocyanate-providing ingredient of the prepolymer.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide liquid stable MDI prepolymers and liquid stable curative systems which are specifically adapted for room temperature casting and which yield high performance urethane elastomers upon room-temperature curing, the elastomer itself, as well as commercial combinations of the prepolymer and its complementary curative, separately packaged but together as a single unit or kit. Other objects of the invention will become apparent hereinafter.
SUMMARY OF THE INVENTION
What we believe to be our invention, then, inter alia, comprises the following, singly or in combination:
A room-temperature liquid stable prepolymer (P) which is the reaction product of
a) methylene diphenylisocyanate or a prepolymer of methylene diphenylisocyanate and an about 500-1000 equivalent weight polytetramethylene ether glycol or polyoxypropylene/polyoxyethylene diol or triol having at least 21% residual NCO,
b) polytetramethylene ether glycol of about 500 to 1000 equivalent weight, and
c) a polyoxypropylene/polyoxyethylene triol or polyoxypropylene triol of about 1300 to 2000 equivalent weight,
the percentage by weight in the prepolymer (P) being about 32 to 72% of (a), about 52 to 22% of (b), and about 6 to 15% of (c), and the percentage of residual NCO in the prepolymer (P) being about 6 to 18% by weight,
the prepolymer (P) having a viscosity at room temperature of about 1200 to 26000 cps,
which prepolymer (P) is curable and castable at room temperature to yield a high-performance urethane elastomer;
such a prepolymer (P) wherein the percentage of residual NCO in the prepolymer (P) is about 11.5-13.5% by weight and wherein the prepolymer (P) has a room temperature viscosity of about 3500 to 5000 cps;
such a prepolymer (P) wherein a) is methylene diphenylisocyanate;
such a prepolymer (P) wherein c) is a polyoxypropylene/polyoxyethylene triol having an equivalent weight of about 1300 to 2000 or a polyoxypropylene triol having an equivalent weight of about 1300 to 2000;
such a prepolymer (P) wherein (a) is a liquid uretonimine-modified methylene diphenylisocyanate;
such a prepolymer (P) wherein b) has an equivalent weight of about 500;
such a prepolymer (P) wherein b) has an equivalent weight of about 1000;
such a prepolymer (P) wherein a) is a previously-prepared reaction product of methylene diphenylisocyanate and polytetramethylene ether glycol having an equivalent weight of about 500 to 1000;
such a prepolymer (P) wherein a) is a previously-prepared reaction product of methylene diphenylisocyanate and a polyoxypropylene/polyoxyethylene diol having an equivalent weight of about 500 to 1000;
such a prepolymer (P) which is curable at room temperature with an approximately stoichiometric equivalent of a liquid curative consisting essentially of the following components:
(1) a polyoxypropylene/-polyoxyethylene diol of about 1000 to 2000 equivalent weight, (2) a polyoxypropylene/-polyoxyethylene triol of about 1300 to 2000 equivalent weight, (3) a chain extender having an equivalent weight of about 25 to 125, (4) a room-temperature liquid stable prepolymer (P) having a 6 to 18% residual NCO, (5) a diluent, (6) a degassing aid, and (7) a urethane catalyst, the relative amounts by weight being respectively 30-90%, 3-20%, 5-30%, 0-30%, 0-15%, 0.001-0.05%, and 0.01-0.5%;
such a prepolymer (P) which is cured at room temperature with an approximately stoichiometric equivalent of a liquid curative consisting essentially of the following components:
(1) a polyoxypropylene/-polyoxyethylene diol of about 1000 to 2000 equivalent weight, (2) a polyoxypropylene/-polyoxyethylene triol of about 1300 to 2000 equivalent weight, (3) a chain extender having an equivalent weight of about 25 to 125, (4) a room-temperature liquid stable prepolymer (P) having a 6 to 18% residual NCO, (5) a diluent, (6) a degassing aid, and (7) a urethane catalyst, the relative amounts by weight being respectively 30-90%, 3-20%, 5-30%, 0-30%, 0-15%, 0.001-0.05%, and 0.01-0.5%;
such a cured prepolymer wherein the amounts of (4) and (5) in the curative are respectively 10-20 and 5-15% by weight;
such a prepolymer (P) which is curable at room temperature with an approximately stoichiometric equivalent of a liquid curative consisting essentially of the following components:
(1) a polyoxypropylene/-polyoxyethylene diol of about 1000 to 2000 equivalent weight, (2) a polyoxypropylene/-polyoxyethylene triol of about 1300 to 2000 equivalent weight, (3) a chain extender having an equivalent weight of about 25 to 125, (4) a room-temperature liquid stable prepolymer (P) having a 6 to 18% residual NCO, (5) a diluent, (6) a degassing aid, and (7) a urethane catalyst, the relative amounts by weight being respectively 30-90%, 3-20%, 5-30%, 0-30%, 0-15%, 0.001-0.05%, and 0.01-0.5% to give a cured urethane elastomer having the following properties after mixing and curing for seven days at room temperature:
Tensile strength (ASTM Method D-412)
about 1300-2700 psi
Elongation (ASTM Method D-412)
about 250-700%
Die C Tear (ASTM Method D-695)
about 140-400 pli
Split Tear (ASTM Method D-1938)
about 20-100 pli
Rebound (ASTM Method D-2632)
about 45-65%
Shore A Hardness (ASTM Method D-2240)
about 70-95
Gel time (25° C.)
about 14-40 min.;
such a prepolymer (P) wherein the percentage of residual NCO in the prepolymer (P) is about 11.5-13.5% by weight and wherein the prepolymer (P) has a room temperature viscosity of about 3500 to 5000 cps and is cured at room temperature with an approximately stoichiometric equivalent of a liquid curative consisting essentially of the following components:
(1) a polyoxypropylene/-polyoxyethylene diol of about 1000 to 2000 equivalent weight, (2) a polyoxypropylene/-polyoxyethylene triol of about 1300 to 2000 equivalent weight, (3) a chain extender having an equivalent weight of about 25 to 125, (4) a room-temperature liquid stable prepolymer (P) having a 6 to 18% residual NCO, (5) a diluent, (6) a degassing aid, and (7) a urethane catalyst, the relative amounts by weight being respectively 30-90%, 3-20%, 5-30%, 0-30%, 0-15%, 0.001-0.05%, and 0.01-0.5% and a room-temperature viscosity of about 300-50000 cps, to give a cured urethane elastomer having the following properties after mixing and curing for seven days at room temperature:
Tensile strength (ASTM Method D-412)
about 1300-2700 psi
Elongation (ASTM Method D-412)
about 250-700%
Die C Tear (ASTM Method D-695)
about 140-400 pli
Split Tear (ASTM Method D-1938)
about 20-100 pli
Rebound (ASTM Method D-2632)
about 45-65%
Shore A Hardness (ASTM Method D-2240)
about 70-95
Gel time (25° C.)
about 14-40 min.;
such a cured prepolymer wherein the amounts of (4) and (5) in the curative are respectively 10-20 and 5-15% by weight;
such a cured product wherein the prepolymer (P) is present in an up to about 13% stoichiometric excess with respect to the curative;
such a cured product wherein the prepolymer (P) is present in about a 2 to 7% stoichiometric excess with respect to the curative;
such a prepolymer (P) wherein the percentages by weight of a), b), and c) are respectively about 54%, about 36%, and about 10%;
such a prepolymer (P) cured with an approximately stoichiom
Doyle James E.
Freeland Gerard Scott
AZON USA Inc.
Flynn ,Thiel, Boutell & Tanis, P.C.
Sergent Rabon
LandOfFree
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