Urea (thiourea) derivative and thermal recording sheet using the same

• US 5,661,100 A
• Filed: 08/29/1995
• Issued: 08/26/1997
• Est. Priority Date: 08/31/1994
• Status: Expired due to Fees

• Current Assignee: Api Corporation (UBE Corporation)
• Original Assignee: Nippon Paper Industries Company Limited (Nippon Paper Group Incorporated), Yoshitomi Pharmaceutical Industries, Ltd. (UBE Corporation)
• Inventors: Minami, Toshiaki, Kinishi, Ryoichi, Minakami, Ryuzo, Hamada, Kaoru, Nagai, Tomoaki, Sekine, Akio
• Primary Examiner(s): Hess, Bruce H.
• Application Number:
  US08/521,031
• Time in Patent Office: 728 Days
• Field of Search: 503/208, 503/209, 503/216, 503/217, 503/225
• US Class Current: 503/209
• CPC Class Codes: B41M 5/3333 Non-macromolecular compounds
• CPC Class Codes: B41M 5/3336 Sulfur compounds, e.g. sulfones, sulfides, sulfonamides
• CPC Class Codes: C07C 311/51 Y being a hydrogen or a carbon atom
• CPC Class Codes: C07C 335/16 having nitrogen atoms of thiourea groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton
• CPC Class Codes: C07C 335/22 being further substituted by carboxyl groups

Abstract

A thermal recording sheet wherein a compound of Formula (I) or (II) is contained in a thermal color developing layer including a basic colorless dye and an organic color developer as main ingredients: ##STR1## (wherein A denotes hydrogen atom, an alkyl group of C₁ to C₄, an alkoxy group of C₁ to C₄, hydroxy group, or nitro group. R₁, R₂, and R₃ are hydrogen atom, an alkyl group of C₁ to C₄, an alkoxy group of C₁ to C₄, hydroxy group, or nitro group. R₁ and R₂ may combine with each other to form an aromatic ring. Y is sulfur or oxygen atom.), ##STR2## (wherein B denotes hydrogen atom, an alkyl group of C₁ to C₄, an alkoxy group of C₁ to C₄, hydroxy group, or nitro group. R₁, R₂, and R₃ are hydrogen atom, an alkyl group of C₁ to C₄, an alkoxy group of C₁ to C₄, hydroxy group, or nitro group. R₁ and R₂ may combine with each other to form an aromatic ring. Y is sulfur or oxygen atom.).

The thermal recording sheet has a high sensitivity and high image stability.

Claims

1. A thermal recording sheet comprising a substrate having thereon a thermal color developing layer containing a colorless or pale colored, basic dye and an organic color developer as main ingredients, wherein said thermal color developing layer contains at least one compound of the following Formula (I) ##STR11## wherein A denotes a hydrogen atom, an alkyl group of C₁ to C₄, an alkoxy group of C₁ to C₄, a hydroxy group or a nitro group,

R₁, R₂, and R₃ are each independently a hydrogen atom, an alkyl group of C₁ to C₄, an alkoxy group of C₁ to C₄, a hydroxy group or a nitro group, and R₁ and R₂ may combine with each other to form an aromatic ring, and

Y is a sulfur or an oxygen atom;

or of the following Formula (II) ##STR12## wherein B denotes a hydrogen atom, an alkyl group of C₁ to C₄, an alkoxy group of C₁ to C₄, a hydroxy group or a nitro group,

R₁, R₂, and R₃ are each independently a hydrogen atom, an alkyl group of C₁ to C₄, a hydroxy group or a nitro group, and R₁ and R₂ may combine with each other to form an aromatic ring, and

Y is a sulfur or an oxygen atom.

2. The thermal recording sheet of claim 1, wherein said thermal color developing layer contains said at least one compound of the Formula (I) or the Formula (II) as an organic color developer in an amount of 1 to 8 parts based on 1 part of said basic dye.

3. The thermal recording sheet of claim 1, wherein said thermal color developing layer contains said at least one compound of the Formula (I) or the Formula (II) as a stabilizer in an amount of 0.25 to 3 parts based on 1 part of said basic dye.