An object of the present invention is to provide a heat sensitive recording material which can develop color at high density by the inclusion of a novel guanidine compound which is strongly basic and superior in diffusion resistance. The present invention for attaining the above-described object is a heat sensitive recording material comprising a substrate supporting thereon a heat sensitive recording layer containing a diazonium salt compound, a coupler which reacts with the diazonium salt compound when heated to develop color, and abase, wherein the heat sensitive recording layer includes as the base at least one of the guanidine compounds represented by the general formula (1):
1
, wherein, in the general formula (1) , R
1
and R
2
represent an alkyl group or aryl group and may be the same or different, R
3
and R
4
represent a hydrogen atom, alkyl group or halogen atom and may be the same or different, and X represents a divalent connecting group.
本发明的目的是提供一种热敏记录材料,通过加入一种新型
胍化合物,该化合物具有强碱性和优越的抗扩散性,可在高密度下显色。为达到上述目的,本发明是一种热敏记录材料,它包括一个基片,基片上支撑着一个含有重氮盐化合物的热敏记录层,一个在加热时与重氮盐化合物反应而显色的耦合剂,以及一个碱基,其中热敏记录层包括至少一种由通式(1)表示的
胍类化合物作为碱基:
1
其中,在通式(1)中,R
1
和 R
2
代表烷基或芳基,可以相同或不同,R
3
和 R
4
代表氢原子、烷基或卤素原子,可以相同或不同,X 代表二价连接基团。