Linerless labels

Linerless labelstock capable for forming thermally imaged markings have a bar reflectance of less than 20 at 670 nanometers, a print contrast signal of at least 80 useful for optical scanning, and a BNL background of at least 75%, the markings being imaged on a linerless label stock by selective application of heat to form a machine readable pattern, the linerless label stock comprising a substrate having first and second surfaces, and having coatings on the first and second surfaces,

• the coatings on the first surface comprising a pressure sensitive adhesive,
• the coatings on the second surface comprising:
• a thermally imaging coating, the thermally-imaging coating containing at least one chromogenic material, said chromogenic material being selected from compounds of the formula (I)
• wherein R1 and R2 are selected from methyl, ethyl, aryl, aryl substituted with methyl, ethyl, methoxy, ethoxy or halogen, benzyl or benzyl with phenyl substituted with methyl, ethyl, methoxy, ethoxy or halogen,
• wherein R3,R4,R5 and R6 are selected from hydrogen, halogen, methyl, ethyl, methoxy, ethoxy or phenyl,
• wherein R7 and R8 are each independently selected from methyl or ethyl,
• wherein R9 is selected from hydrogen, methoxy or ethoxy,
• wherein R10 is selected from hydrogen, dimethylamino or diethylamino,
• wherein R11 is methyl,
• and at least one developer of the formula (II)
• and, a release coat, the release coat having a low adherence to the pressure sensitive adhesive on the first surface.

Improved thermally imaging linerless label stock useful for optical scanning comprising a substrate having first and second surfaces, and having coatings on the first and second surfaces,

• the coatings on the first surface comprising a pressure sensitive adhesive,
• the coatings on the second surface comprising:
• a thermally imaging coating, the thermally-imaging coating containing at least one developer of the formula (II)
• and at least one, chromogenic material capable of converting under the application of heat and reactive contact with the acidic developer to a colored form having a bar reflectance of less than 20 at 670 nanometers, said chromogenic material being selected from compounds of the formula (I)
• wherein R1 and R2 are selected from methyl, ethyl, aryl, aryl substituted with methyl, ethyl, methoxy, ethoxy or halogen, benzyl or benzyl with phenyl substituted with methyl, ethyl, methoxy, ethoxy or halogen,
• wherein R3,R4,R5 and R6 are selected from hydrogen, halogen, methyl, ethyl, methoxy, ethoxy or phenyl,
• wherein R7 and R8 are each independently selected from methyl or ethyl,
• wherein R9 is selected from hydrogen, methoxy or ethoxy,
• wherein R10 is selected from hydrogen, dimethylamino or diethylamino,
• wherein R11 is methyl,
• and, a release coat, the release coat having a low adherence to the pressure sensitive adhesive on the first surface,
• wherein the linerless label stock when thermally imaged displaying a print contrast signal of at least 80 and a BNL background of at least 75%,
• wherein the label stock has a spiral roll configuration such that the pressure sensitive adhesive adheres to the release coat to maintain the roll configuration, and wherein the stock may be peeled off the roll at the outer end of the roll.

Improved thermally imaging linerless label stock useful for optical scanning comprising a substrate having first and second surfaces, and having coatings on the first and second surfaces,

• the coatings on the first surface comprising a pressure sensitive adhesive,
• the coatings on the second surface comprising:
• a thermally imaging coating, the thermally-imaging coating containing at least one chromogenic material, the thermally imaging linerless label stock when imaged having a bar reflectance of less than 20 at 670 nanometers, a print contrast signal of at least 80 useful for optical scanning, and a BNL background of at least 75%, said chromogenic material being selected from compounds of the formula (I)
• wherein R1 and R2 are selected from methyl, ethyl, aryl, aryl substituted with methyl, ethyl, methoxy, ethoxy or halogen, benzyl or benzyl with phenyl substituted with methyl, ethyl, methoxy, ethoxy or halogen,
• wherein R3,R4,R5 and R6 are selected from hydrogen, halogen, methyl, ethyl, methoxy, ethoxy or phenyl,
• wherein R7 and R8 are each independently selected from methyl or ethyl,
• wherein R9 is selected from hydrogen, methoxy or ethoxy,
• wherein R10 is selected from hydrogen, dimethylamino or diethylamino,
• wherein R11 is methyl,
• and including at least one developer for the formula (II)
• and, a release coat, the release coat having a low adherence to the pressure sensitive adhesive on the first surface
• wherein the label stock has a Z fold stack configuration such that the pressure sensitive adhesive adheres to the release coat to maintain the Z fold stack configuration, and wherein the stock may be peeled off the stack at the outer end of the stack.