A composition for forming a visually discernible color, the use of this composition for producing a heat-sensitive recording material, the corresponding heat-sensitive recording material includes a substrate and this composition, and a process for producing the heat-sensitive recording material.

Aspects of the invention include color change compositions having a color former and color developer composition that transitions from a first color state to a second color state upon application of an applied stimulus and an amount of a copolymer sufficient to eliminate background color of the color former and color developer composition during transition from the first color state to the second color state. Methods for preparing and devices employing the color change compositions of the invention are also described.

Provided is a thermosensitive recording medium being excellent in oil resistance among various performances required for the thermosensitive recording medium, and being further excellent in heat resistance, plasticizer resistance, and printing (recording) run-ability. That is a thermosensitive recording medium having a thermosensitive recording layer comprising a colorless or pale colored electron donating leuco dye and an electron accepting color developing agent on a substrate, wherein the thermosensitive recording layer contains at least two kinds of urea compounds. The two kinds of urea compounds comprise the first urea compound being represented by the following general formula 1, and the second urea compound being represented by the following general formula 2. ##STR00001##
wherein R.sup.1 represents a substituted or unsubstituted alkyl group, aralkyl group or aryl group, and R.sup.2 represents a hydrogen atom or an alkyl group, ##STR00002##
wherein R.sup.4 to R.sup.8 represent a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, an alkoxy group, an aryloxy group, and the like, and m represents an integer of 0 to 2.

Provided are thermochromic color-memory composition and thermochromic color-memory microcapsule pigment encapsulating the same, the thermochromic color-memory composition including: (a) a component composed of an electron-donating color-developing organic compound; (b) a component composed of an electron-accepting compound; and (c) a component composed of an ester compound represented by the following Formula (1) as a reaction medium which controls color reaction between the components (a) and (b):

##STR00001##

(wherein, R represents an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom; Y represents a hydrogen atom or a methyl group; and Z represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom).

A heat-sensitive recording material including a web-shaped substrate having a front side and an opposite reverse side, and at least one heat-sensitive recording layer on either or both of the sides of the web-shaped substrate.

The heat-sensitive recording layer contains a color acceptor having a combination at least consisting of one, two, three or more than three color acceptor (compounds) of formula (1)

##STR00001## where R is alkyl, and of at least one secondary color acceptor comprising lactic acid oligomers conforming to formula (3)

##STR00002##

A thermosensitive recording material including a compound represented by the following formula (1): ##STR00001##
wherein, R.sup.1 to R.sup.10 each independently represent a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, an alkoxy group, an aryl oxy group, an alkyl carbonyl oxy group, an aryl carbonyl oxy group, an alkyl carbonyl amino group, an aryl carbonyl amino group, an alkyl sulfonyl amino group, an aryl sulfonyl amino group, a monoalkyl amino group, a dialkyl amino group, or an aryl amino group.

Disclosed is a heat-sensitive recording material comprising at least an undercoat layer and a heat-sensitive recording layer in this order on a support, the undercoat layer containing an inorganic pigment, hollow particles, and a binder, the heat-sensitive recording layer containing a leuco dye, developers, and a binder, the heat-sensitive recording layer containing a first developer and a second developer as the developers, the heat-sensitive recording layer containing an N,N-diarylurea-based compound represented by formula (1) as the second developer:

##STR00001## wherein R.sub.2 represents a C.sub.1-12 alkyl group, a C.sub.7-12 aralkyl group, or a C.sub.6-12 aryl group, the aralkyl group and aryl group may be substituted with a C.sub.1-12 alkyl group, a C.sub.1-12 alkoxy group, a C.sub.6-12 aryl group, or a halogen atom, and a plurality of R.sub.2s may be the same or different; and A.sub.1 represents a hydrogen atom or a C.sub.1-4 alkyl group, and a plurality of A.sub.1s may be the same or different.

A recording medium has a substrate and a thermally responsive layer disposed on the substrate. The thermally responsive layer includes a leuco dye and at least one developer. The developer comprises an N,N-diurea derivative of Structure I and an N,N-diurea derivative of Structure II:

##STR00001##

wherein each R.sub.n is independently a C.sub.1-7 alkyl group.

The present invention provides a heat-sensitive recording material which has improved thermal responsiveness and improved stability of the print part and the background in comparison to conventional heat-sensitive recording materials that contain a non-phenolic compound as a color developer. The present invention provides a heat-sensitive recording composition which contains a color former, a color developer and a stabilizer, wherein: N-[2-(3-phenylureido)phenyl] benzenesulfonamide or N-(p-toluenesulfonyl)-N-(3-p-toluenesulfonyloxyphenyl) urea is contained as the color developer, and 1,3-diphenyl urea is contained as the stabilizer.

Provided is a display medium configured to allow for intended drawing. The display medium includes a first recording layer capable of performing recording with a first laser beam having a first peak wavelength and a second recording layer capable of performing recording with a second laser beam having a second peak wavelength. The first recording layer and the second recording layer employ different recording methods.