Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Patent
1991-01-09
1992-04-07
Welsh, Maurice J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
521112, 521118, 521125, 521128, 521129, 521131, 521159, 521160, 521161, 544180, 544193, C08G 1814
Patent
active
051029189
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a modified organic polyisocyanate having an isocyauurate ring, more particularly to a process for producing a modified organic polyisocyanate which is readily producible, being in a liquid state, superior in compatibility with other resins, and stable, and has an isocyanurate ring. Further, the present invention relates to a process for producing a modified polymethylenepolyphenylpolyisocyanate, a storable resin composition and a foam prepared from the same, and more particularly to a process for producing a modified polymethylenepolyphenyl polyisocyanate having an isocyanurate ring, a storable resin composition prepared from the modified product and a polyol, and a process for producing therefrom a polyisocyananurate foam having low smoking property.
TECHNICAL BACKGROUND
Organic polyisocyanates are utilized hitherto for various applications as foams, elastomers, paints, adhesives and the like by the reaction with active hydrogen compounds.
Such an organic polyisocyanate can also be used by the modification to a polyisocyanate compound having an isocyanurate ring.
The product prepared by reaction of the modified polyisocyanate compound with an active hydrogen compound has heat resistance, flame resistance, rigidity, toughness and the like which are characteristic of isocyanurates, and is utilized in applications where such properties are required.
Accordingly, a variety of isocyanuration polymerization is conducted for isocyanuration of organic polyisocyanates. (The term "isocyanuration" means hereinafter a trimerization of an isocyanate compound to form an isocyanurate ring.) For example, Japanese Patent Laid-open Publications Sho. 54-32490 and Sho. 52-69497 respectively describe methods for the isocyanuration by use of a catalyst such as a metal salt of acetylacetone, an alkali metal salt of an organic acid, and the like. These production processes are not satisfactory, because the selectivity of the catalyst is very narrow for the organic polyisocyanate; and particularly in the isocyanuration polymerization, an organic isocyanate in which the difference between the reactivities of the first and the second isocyanate groups is little like those in diphenylmethane diisocyanate is liable to polymerize to become viscous and to give a partially non-uniform product having a low isocyanate content and low compatibility with other resins.
Further, upon carrying inactivation of the catalyst in order to improve stability of the modified polyisocyanate, if the reaction is conducted without a solvent insoluble precipitate tends to be formed and it is difficult to control the isocyanuration reaction, so that it is not satisfactory industrially and improvement thereof has been desired. In other words, a modified organic polyisocyanate having an isocyanurate ring has been desired which is prepared readily through isocyanuration of an organic polyisocyanate, and which is stable in storage, and excellent in compatibility to other resins.
Heretofore, the preparation of a polyisocyanurate foam having flame resistance and low smoking property has been carried out in the presence of a trimerization catalyst upon a reaction of a polyisocyanate with an active hydrogen compound. However, further improvement of the properties are desired.
A polymethylenepolyphenyl-polyisocyanate (hereinafter referred to as "polymeric MDI") exhibits heat resistance based on its characteristic feature when reacted with polyols.
Polymeric MDI solely or a polyol adduct of polymeric MDI is used nowadays. However, polyol adducts are liable to deteriorate by heat, and are limited in use for flame-resistant foams.
Polyisocyanurate foams are widely used for heat insulating materials, light-weight structural materials, and sound absorption materials because of their superior characteristics. The introduction of the isocyanurate ring into polyurethane crossliking makes heat resistance, hydrolysis resistance, and dimension stability higher. However, the application fields thereof is limited because of an
REFERENCES:
patent: 4412073 (1983-10-01), Robin
patent: 4454317 (1984-06-01), Disteldorf
patent: 4499253 (1985-02-01), Kerimis
patent: 4537961 (1985-08-01), Robin
Nippon Polyurethane Industry Co., Ltd.
Welsh Maurice J.
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