TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No general preparation is given. Preferred Compound: The melamine compound is of formula (2).R2-R5,n=same as defined above;andR6=H or alkyl.Preferred Method: The melamine derivative is obtained by reacting a triazine compound of formula (3) and an amino alcohol of formula (4).R2-R5,n=same as defined above;andX=halogen.Preferred Agent: The crosslinking agent is a derivative of an acrylic acid which has 2 or more radical polymerizable functional groups. The acrylic acid derivative is of formula (5):Y'-C(=O)-C(CH2)-R6.Y'=alkoxy, hydroxy or halogen;andR6=same as defined above.Preferred Composition: The usage amount of the crosslinking agent with respect to total amount of the proton conducting compound and the crosslinking agent is 0.1-50 weight%.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: A proton conducting polymer is obtained by polymerizing the proton conducting compound and a crosslinking agent. Preferred Composition: A solid electrolyte contains proton conducting polymer (1-80 weight.%) and thermoplastic polymer (20-99 weight.%) other than the proton conductive polymer. Preferred Definitions:    R1=CH2=CR6-CO-O(CH2)n-.    SPECIFIC COMPOUNDS - 6 Specific melamine compounds are disclosed, such as compound of formulae (6-10).    EXAMPLE - N-butylamine (in mmol) (150) was dissolved in dimethylacetamide (50 ml) and cooled at 0 degrees C. Then, dimethylacetamide solution (50 ml) of diisopropyl ethylamine (250) and N,N'-dibutyl-6-chloro-(1,3,5)triazine-2,4-diamine (50) was added and heat-refluxed for 4 hours, and cooled to obtain N,N',N"-tributyl(1,3,5)triazine-2,4,6-triamine. The obtained N,N',N"-tributyl(1,3,5)triazine-2,4,6-triamine (10) was added to methanol solution of bis(trifluoro methanesulfonic acid)imide (10) and stirred. The obtained mixture was distilled for 30 minutes, to obtain bis(trifluoro methanesulfonic acid)imide salt of N,N',N"-tributyl(1,3,5)triazine-2,4,6-triamine. The obtained bis(trifluoro methanesulfonic acid)imide salt of N,N',N"-tributyl(1,3,5)triazine-2,4,6-triamine, had proton conductivity of 6 mS/cm at 150 degrees C.