Abstract: A polyurethane elastic fiber made from a polyurethane obtained from a copolymerized polyalkyleneether diol composed of different alkyleneethers containing 2-10 carbon atoms; the polyurethane comprises a urethane portion having a number average molecular weight of 6000-9500 and a urea portion having a number average molecular weight of 650-950. The polyurethane elastic fiber has improved elastic functions such as high elongation at break (elongation at break is 500%, or more), low modulus (300% modulus is 0.20 g/d, or less), excellent low temperature characteristics, and heat resistance; and, therefore, creation of highly excellent converted goods is made possible.

Abstract: A diaminourea compound having the formula (I); ##STR1## wherein R.sub.1 and R.sub.2 are independently a straight or branched alkylene group having 2 to 8 carbon atoms, an alicyclic alkylene group having 6 to 15 carbon atoms, a phenylene group, a C.sub.1 -C.sub.4 alkyl-substituted phenylene group, a C.sub.1 -C.sub.4 mono- or di-alkylene substituted phenylene group, or a methanediphenylene group, and a production process thereof as well as a high heat resistant polyurethaneurea derived therefrom and a production process thereof.

Abstract: A diaminourea compound having the formula (I); ##STR1## wherein R.sub.1 and R.sub.2 are independently a straight or branched alkylene group having 2 to 8 carbon atoms, an alicyclic alkylene group having 6 to 15 carbon atoms, a phenylene group, a C.sub.1-C.sub.4 alkyl-substituted phenylene group, a C.sub.1-C.sub.4 mono- or di-alkylene substituted phenylene group, or a methanediphenylene group, and a production process thereof as well as a high heat resistant polyurethaneurea derived therefrom and a production process thereof.

Abstract: A monoester compound of a 2,2'-alkylidene bis(4,6-di-substituted phenol) useful as an antioxidant in synthetic polymers having good resistant to oxides of nitrogen fumes, represented by the formula (I), ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a C.sub.1-4 alkyl group, a C.sub.5-6 cycloalkyl group or a methyl-substituted C.sub.5-6 cycloalkyl group; and one of R.sub.3 and R.sub.4 represents a hydrogen atom and the other represents a hydrogen atom or a C.sub.1-10 alkyl group or both of them represent a methyl group; R.sub.5 represents a C.sub.4-9 alkyl group, a C.sub.3-7 cycloalkyl group, a C.sub.2-4 alkenyl group, a phenyl group, a C.sub.1-4 alkyl-substituted phenyl group, a C.sub.1-4 alkoxy-substituted phenyl group, a mono- or di- C.sub.1-4 alkyl-substituted hydroxyphenyl group, a styryl group, a benzyl group or a pyridyl group, and a method of preparing such a monoester compound.