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...
Patent
1992-06-29
1993-09-28
Welsh, Maurice J.
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...
524700, 524730, 524265, 528 48, 528 28, 2521822, 25218221, 25218222, C08L 7504
Patent
active
052487148
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a polyisocyanate composition having an excellent low temperature storage stability.
Polyisocyanates, e.g., polymethylene polyphenyl polyisocyanate (hereinafter referred to as "polymeric MDI" or "C-MDI") are used for in many diverse applications, such as interior members such as handles and instrument pads, as automobile members, daily miscellaneous goods such as adhesives, household electric appliances such as heat insulating material for electric refrigerators, external wall materials such as side panels, heat insulating building materials such as heat insulating shutters and doors, structural heat insulating materials such as pipes and tanks, and the like.
2. Background Art
Due to the range of utilization of polymeric MDI and the derivatives thereof they are used for the production of many polyurethane products, and accordingly, although there exists a wide range of storage conditions of the raw material of these products, there are few factories or plants where the storage conditions of these substances in drum cans, oilcans or the like are thoroughly supervised. In particular, for an in situ foaming, such as spray foaming, a temperature control is not effected under normal conditions. Therefore, in winter, the raw material storage temperature is often about -10.degree. C., even in places other than severe cold districts. The studies and developments of the improvement of the storage stability of polymeric MDI and the derivatives thereof are continued on a wide scale, and isocyanate makers have put on sale large amounts of polymeric MDI with a viscosity of 160 centipoises (hereinafter referred to as "cps") or more at 25.degree. C., which has very excellent storage stability at -10.degree. C. and is not subjected to any separation of crystals and the like.
Nevertheless, the low viscosity polymeric MDI with a viscosity at 25.degree. C. of not higher than 160 cps, especially between 90 and 130 cps, contains a large amount of diphenylmethane diisocyanate (hereinafter referred to as "MDI") with a melting point of 38.degree. C., and this MDI is separated at a low temperature of about -10.degree. C., and thus problems arise regarding the storage stability thereof.
Also, in line with the governmental restraint on fleon gas, started 1990, there will be an increased demand for polymeric MDI, which has a low viscosity and an excellent low temperature storage stability. Further, polyisocyanate having an excellent low temperature storage stability only is urgently required by cellular plastics makers. Nevertheless, there are no known additives soluble in polymeric MDI which can inhibit the change in reactivity and properties of the polyurethane resins obtainable therefrom to the minimum without greatly lowering the isocyanate content (hereinafter referred to as "NCO content" or "NCO %").
Furthermore, polymeric MDI contains a dimer with a concentration not lower than a predetermined value, which is insoluble in polyisocyanate comprising mutually bonded isocyanate groups, and the low temperature storage stability of polymeric MDI is influenced also by this concentration. Since this dimer is often produced when the temperature is elevated, close attention has been paid to the storage of this polymeric MDI, and the development of an isocyanate with the lowest possible storage temperature is urgently required.
DISCLOSURE OF THE INVENTION
The present inventors made intensive studies, and as a result, found that a composition comprising a polyisocyanate compound to which a silicate compound is added has a particularly good low temperature storage stability, and thus accomplished the present invention.
The present invention provides a polyisocyanate composition comprising 0.1% by weight or more 10% by weight of a silicate compound dissolved or dispersed in at least one kind of polyisocyanate compound selected from the group consisting of diphenylmethane diisocyanate oligomers containing 20 to 60% by weight of diphenylmethane diisocyanate and the derivatives
REFERENCES:
patent: 4332742 (1982-06-01), Allen
patent: 5102937 (1992-04-01), Warren et al.
Katano Hiroaki
Tanaka Tetsuya
Yamaguchi Shigeru
Dow Mitsubishi Kasei Limited
Welsh Maurice J.
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