| 摘要 |
<p>A method for hardening gelatin which comprises using as a hardening agent a compound represented by formula (I): <CHEM> wherein R<5>, when taken along, may be alkyl of 1 to 20 carbon atoms, aralkyl of front 7 to 20 carbon atoms, aryl of from 6 to 20 carbon atoms, and alkenyl of from 2 to 20 carbon atoms. R<5> and R<6> can also combine with each other to form a heterocyclic ring of 5 to 8 atoms. The R<5>-R<6> ring contains the nitrogen atoms to which R<5> and R<6> are attached, and may also contain an additional nitrogen atom. R<6> and R<7> can combine to form either a 5 or 6 membered ring. The R<6>-R<7> ring contains the nitrogen atom to which R<6> is attached, and may also contain one or two additional nitrogen atoms. R<8> may be hydrogen or alkyl of 1 to 4 carbon atoms. R psi may be hydrogen or one or more substituents at any of positions 3 through 6 on the pyridine ring, including alkyl of 1 to 20 carbon atoms, aryl of from 6 to 20 carbon atoms, aralkyl of from 7 to 20 carbon atoms, or alkenyl of from 2 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms, aryloxy of from 6 to 20 carbon atoms, carboxy, halogen, nitro, or sulfo. R psi may be in a fused ring structure such as in quinoline. X DIVIDED represents an anion or an anionic portion of compounds of formula (I) effectively harden gelatin with little or no afterhardening. These compounds are useful in hardening gelatin in photographic elements.</p> |
