Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Patent
1991-09-06
1992-08-11
Welsh, Maurice J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
2521822, 528 48, 528370, 528371, C08G 1808
Patent
active
051380153
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
A polyurethane useful as a coating material can be produced by preparing a dialkyl carbonate substantially without using phosgene, reacting the carbonate with a diamine to give a urethane, thermally decomposing the urethane into a diisocyanate and reacting the diisocyanate with a polyol or the like in the presence of a Lewis acid or a protonic acid. The reaction of a diisocyanate compound containing a reduced amount of chlorine is promoted by a Lewis acid or a protonic acid.
A diisocyanate compound containing a reduced amount of chlorine is reacted with a polyol, amine or the like to give a polyurethane resin which is industrially useful as a coating material, heat insulator, cushioning material, mechanical part or the like and can be widely utilized in many necessities for daily life for example, automobile parts, domestic electrical appliances, business machines, clothing, household furnitures and so on.
BACKGROUND ART
A polyurethane is used by virtue of its excellent characteristics as a coating material in the form of a composition suitably prepared by mixing it with other components or reacting it with other compounds.
Examples of such a coating material include
(1) curable coating materials for optical fibers, large cathode ray tubes or cosmetic containers comprising a urethane (meth)acrylate resin which is prepared by the reaction of a urethane with a hydroxylated (meth)acrylate and is curable by irradiation with ultraviolet rays or electron beams,
(2) coating materials of cathodic electrodeposition type which are prepared by the reaction of a urethane with a polyester modified epoxy resin, epoxidized polybutadiene resin or glycidylated acrylic resin and are useful as an undercoat for an automobile body, building skeleton or aluminum sash,
(3) polyurethane coating materials for molded articles of thermoplastics, such as an automobile bumper or a wheel cap or wood works such as furniture, door or wooden parts of office facilities,
(4) one pack baking urethane coating materials for metals which are applicable to outer cases of electrical appliances (such as a refrigerator, audio and VCR), metallic automobile parts, blind and roofing and wall covering materials,
(5) two pack acrylic urethane or polyester urethane coating materials which comprise a polyisocyanate compound prepared by converting an isocyanate into an isocyanurate, biuret or allophanate or an isocyanate adduct prepared by the addition reaction of an isocyanate with a low molecular diol or triol and a hydroxylated acrylic resin or a polyester resin and which are usable in the repair of automobiles or are applicable to automobile parts and wood works, and
(6) urethane powder coatings applicable to outer cases of domestic electrical appliances such as a washing machine or office facilities, and anticorrosive coatings containing a urethane prepolymer useful as an intercoating of a bridge, steel frame or automobile body.
These urethane coating materials are generally prepared by the polyaddition of a polyisocyanate compound with a polyol such as polyether polyol, polyester polyol or low-molecular polyhydric alcohol and, if necessary, by the use of an active hydrogen compound as a chain lengthening agent.
Most of the polyisocyanates to be used in the above polyaddition are directly prepared industrially by the reaction of a polyamine with phosgene, excepting ones having a special structure.
In other words, according to the prior art, at least one of the starting materials to be used in the production of a polyurethane is prepared by the use of toxic phosgene in some preparation step.
In the field of various coating materials described above, the resistances of polyurethane which is one of the main components of the coating materials to weather, corrosion and heat are important factors, so that the development of a polyurethane improved in these characteristics has been expected.
In the case as described above wherein at least one of the starting materials is prepared by the use of toxic phosgene in some preparation step, a p
Maruyama Toshihide
Murata Kiyokazu
Yagii Toyokazu
Daicel Chemical Industries Ltd.
Welsh Maurice J.
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