The Upjohn Co.

Other

Warren J Rabourn

Richard A Prather

Bernard D Funk, Jr

David L Williams

Jerardo Mongiello

Robert M Partin

A process is disclosed for the preparation of liquid, storage-stable, polyisocyanate compositions containing a release agent formed in situ which compositions are useful, for example, as binder resins in the formation of particle boards which latter, because of the presence of the release agent, show no tendency to adhere to the face of metal platens used in their formation. The process comprises heating an organic polyisocyanate (polymethylene polyphenyl polyisocyanate preferred) with an acid phosphate (e.g. a mixture of mono- and di-alkyl acid phosphates) under conditions controlled as to time and temperature so as to yield a product which is storage stable and shows no tendency to deposit solid or to separate into two liquid phases.

Polyisocyanate compositions containing in-situ formed pyrophosphate mold

The reactivity of polymethylene polyphenyl isocyanates containing 20 to 90 percent of methylenebis(phenyl isocyanates) is improved, and stabilized against a decline on storage, by incorporating therein very small amounts of a compound of the formula ##STR1## wherein R.sub.1 =alkyl, aryl; R.sub.2 =alkyl; R.sub.3 =H, alkyl or aralkyl; and R.sub.1 and R.sub.2 taken together represent the residue of an oxazoline or oxazine. 2-Ethyloxazoline is the preferred compound for incorporation in the polyisocyanate.

Polyisocyanate compositions

Color stabilized isocyanates, particularly methylene-bridged aromatic isocyanates [methylenebis(phenyl isocyanate) and prepolymers thereof], are derived by incorporating in the isocyanate a color stabilizing amount of a compound of the formula ##STR1## wherein R.sub.1 =alkyl, aryl; R.sub.2 =alkyl; R.sub.3 =H, alkyl or aralkyl; and R.sub.1 and R.sub.2 taken together represent the residue of an oxazoline or oxazine. 2-Ethyloxazoline is a preferred color stabilizing compound. The above compounds can also be used to discharge undesirable colors which have developed in such isocyanates on storage.

Stabilized isocyanate compositions

A continuous process is described for the preparation of methylene-bridged polyphenyl polyamines containing di(aminophenyl)methane having a high, p,p'-isomer content (at least 98 percent by weight). Fluid streams of aqueous aniline hydrochloride solution and aqueous formaldehyde are intermixed at one end of a continuous tubular reactor, passed therethrough at 0.degree.C to 75.degree.C in about 3 seconds to about 120 seconds, thence to recycle in a cooling zone (less than 60.degree.C), optionally to a holding zone (temperature less than 70.degree.C) and finally to a final reaction zone (temperature 60.degree.C to 120.degree.C) to complete the reaction. The diamine content in the polyamines is controlled by molar ratio of aniline hydrochloride to formaldehyde in the feeds. Preferably the holding zone, where employed, and final reaction zone comprise a continuous tubular vessel.

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Deer Park, TX, United States of America

Warren J Rabourn