To provide a thermal recording material which is excellent in coloring sensitivity and in storage stabilty of colored image by using a developer composition prepared by compounding a sulfonamide derivative having a phenolic hydroxy group with a sulfonic ester derivative having an amino group or a sulfonamide derivative having a sulfonic ester group.
This developer composition is prepared by compounding 100 pts.wt. compound of formula I with 0.01-10 pts.wt. ingredient comprising a compound of formula II and/or a compound of formula III. In the formulas, X1 to X3 are each H, a halogen, alkyl, alkoxy, or hydroxyl; and R1 to R5, R11 to R15, and R31 to R35 are each H, a halogen, alkyl, alkoxy, or aryl provided that two adjacent groups selectd from among combinations of R1 with R2, R2 with R3, R11 with R12, R12 with R13, R21 with R22, R22 with R23, R31 with R32, and R32 with R33 may be bonded to each other to form, together with carbon atoms to which they are bonded, a carbocyclic aromatic ring. The composition is incorporated into an electron-accepting compound contained in a thermal recording layer formed on a substrate.
WADA MASARU
NAKATSUKA MASAKATSU
TANABE YOSHIMITSU
KIDA JOTARO
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