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
2000-12-20
2003-01-07
Niland, Patrick D. (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...
C524S198000, C524S590000, C528S044000, C528S060000, C528S065000, C528S085000
Reexamination Certificate
active
06503980
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to liquid polyurethane plasticizers, to a process for preparing these plasticizers, and to a process for the production of a polyurethane comprising reacting a polyisocyanate component with an isocyanate-reactive component in the presence of these liquid polyurethane plasticizers, and to the polyurethanes produced by this process.
Plasticizers are generally used in plastics (i.e., PVC) to adjust the hardness, flexibility and processing characteristics. Plasticizers are also used in some commercial polyurethane elastomer formulations to provide products exhibiting higher flexibility, lower hardness, and lower rebound resulting in increased energy absorption. However, these products potentially embrittle over time due to migration of the plasticizer. Plasticizers that have a minimal effect on hardness and physical properties, and which are non-migrating are desirable for polyurethane elastomers prepared by a one-shot cast elastomer process.
Diurethanes are known and described as suitable stabilizing additives for sealing compounds in, for example, U.S. Pat. No. 4,824,888 and as plasticizers for polyurethane based sealing and adhesive compositions in U.S. Pat. No. 5,525,654.
U.S. Pat. No. 4,824,888 discloses diurethanes which correspond to one of two general formulas, which are useful as stabilizing additives in sealing compounds based on isocyanate-terminated prepolymers of difunctional and trifunctional polyether or polyester polyols and/or polyvinylchloride swellable copolymers of vinyl chloride with monomers from the group vinyl acetate, vinyl propionate and alkyl acrylates. These diurethanes are prepared by the reaction of diols with monoisocyanates and diurethanes prepared from symmetrical diisocyanates with polyether monoalcohols. In particular, the monoalcohols are monofunctional polypropylene glycol monoalkyl ethers having a molecular weight of about 500 to 2000. These diurethanes are also suitable stabilizing agents for isocyanate-terminated polyurethane prepolymers, and for polyvinyl chloride homopolymer or copolymer plastisols.
Moisture curing sealing and/or adhesive compositions based on alkoxysilane-terminated polyurethanes which contain diurethanes as plasticizers are described by U.S. Pat. No. 5,525,654. These diurethanes are prepared from either diol mixtures and monofunctional isocyanates wherein substantially all the free hydroxyl groups are reacted, or from diisocyanates and monofunctional alcohols wherein substantially all the free isocyanate groups are reacted.
Other urethane plasticizers are disclosed in, for example, U.S. Pat. Nos. 4,123,413 and 4,482,408. The urethane plasticizers of U.S. Pat. No. 4,123,413 correspond to one of three general formulas, and are prepared by reaction of an alcohol or a phenol with an isocyanate, from amines and chloroformates, or from chloroformamides and alcohols or phenols in the presence of acid binding agents.
The urethane plasticizer of U.S. Pat. No. 4,482,408 is octyldecyl-butyl urethane and is prepared by reacting an equimolar mixture of octyldecyl isocyanate and n-butyl alcohol. This urethane plasticizer is a mono-urethane described as a straight-chained, saturated, carbamic acid ester and is suitable as a plasticizer for propellant compositions with problems of plasticizer migration which typically occur during propellant storage.
Applicants' copending U.S. Application Ser. No. 09/453,678 filed Dec. 3, 1999 which is commonly assigned, describes a process for the preparation of one-shot polyurethane cast elastomers containing liquid, diurethane non-migrating plasticizers. The liquid diurethane plasticizers have a viscosity of less than 50,000 mPa.s at 50° C., and are prepared from an asymmetrical diisocyanate containing about 32.0 to 48.3% NCO and a monoalcohol having a molecular weight of about 100 to about 1,000.
High molecular weight, liquid, non-migrating, non-functional polyether polyurethane plasticizers having a viscosity of less than 50,000 mPa.s at 50° C. are described in U.S. Pat. No. 6,355,721, issued Mar. 12, 2002, which is commonly assigned. These plasticizers are prepared by reacting an asymmetrical polyisocyanate and a polyether polyol having a molecular weight of about 1,000 to less than about 5,000 and a functionality of about 2 to about 3, to yield an isocyanate prepolymer having an NCO group content of less than 13%. This isocyanate prepolymer is then reacted with a monofunctional alcohol having a molecular weight of about 32 to about 1,000 at an NCO:OH equivalent ratio of 1:1.
Liquid, hydrophobic, non-migrating, non-functional polyurethane plasticizers having a viscosity of less than about 100,000 mpa.s at 50° C. are described in U.S. Pat. No. 6,384,130, issued May 7, 2002, which is commonly assigned. These plasticizers are prepared in two (2) steps. First, a diisocyanate component having an NCO group content of about 25.0 to about 60.0% and a functionality of about 2.0 is reacted with a hydrophobic polyol having a molecular weight of about 200 to about 4,000 to give an isocyanate prepolymer having an NCO group content of less than 20%, and second, a monofunctional alcohol having a molecular weight of about 32 to about 1,000 is reacted with the isocyanate prepolymer formed in the first step at an NCO:OH equivalent ratio of 1:1.
U.S. Pat. No. 6,218,462, which issued Apr. 17, 2001, which is commonly assigned, describes liquid, ultra-high molecular weight polyurethane plasticizers containing less than 5% of urethane groups. These plasticizers are prepared from the reaction of 1) an aliphatic monoisocyanate and a high molecular weight monoalcohol (molecular weight greater than or equal to 4,000), or 2) a diisocyanate and a high molecular weight monoalcohol as described above, or 3) a diisocyanate and a high molecular weight polyether polyol (molecular weight greater than or equal to 4,000).
Useful polyurethane plasticizers according to the present invention are based on (A) one or more isocyanates selected from the group consisting of allophanate modified isocyanates, carbodiimide modified isocyanates and uretonimine modified isocyanates, with (B) at least one isocyanate-reactive compound selected from the group consisting of (1) one or more isocyanate-reactive compounds having a molecular weight of more than about 1,000, an OH number of about 9 to about 112, and a functionality of from about 2 to about 4, and (2) one or more monofunctional alcohols having a molecular weight of about 100 to about 1,000, and an OH number of about 56 to about 560, and, when (B) comprises (1) as described above, this is followed by the addition of (C) a stopper which comprises a low molecular weight monoalcohol. The plasticizers of the present invention are prepared by either adding (B)(2) the alcohol(s) and/or (B)(1) the polyether polyol(s) to (A) the isocyanate component, or by addition of (A) the isocyanate component to (B)(2) the monofunctional alcohol(s) and/or (B)(1) the polyether polyol(s). The polyurethane plasticizers are liquid at 25° C. The resulting polyurethane plasticizers do not contain any free hydroxyl- or isocyanate-groups, and thus they are non-reactive and can be added to either isocyanates or polyols to form stable mixtures.
Surprisingly, it has been found that plasticizers prepared from a modified polyisocyanate which contains allophanate groups, carbodiimide groups and/or uretonimine groups exhibit reduced migration in a polyurethane elastomer vs. a plasticizer as in Applicants' copending applications described above. In an extraction test, much less of the plasticizers of the present invention can be removed from a polyurethane elastomer than can be removed of Applicants earlier plasticizers in polyurethane elastomers. In addition, the plasticizers of the presently claimed invention result in elastomers exhibiting improved tear strength vs. elastomers containing plasticizers of the prior art and even Applicants' previously described plasticizers.
The use of these polyurethane plasticizers in one-shot elastomers has several important
Markusch Peter H.
Pantone Richard S.
Bayer Corporation
Brown N. Denise
Gil Joseph C.
Niland Patrick D.
LandOfFree
Liquid polyurethane plasticizers containing allophanate... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid polyurethane plasticizers containing allophanate..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid polyurethane plasticizers containing allophanate... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3009257