Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or...
Patent
1989-01-13
1990-10-09
Hess, Bruce H.
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
156295, 156305, 427152, 503207, 503226, B41M 522
Patent
active
049620720
DESCRIPTION:
BRIEF SUMMARY
The invention relates to paper for carbonless copy paper sets and to copy paper sets made up using it.
BACKGROUND
Carbonless copy paper sets consist of a top sheet known as the CB (coated back) sheet, a back sheet known as the CF (coated front) sheet, and optionally one or more intermediate sheets known as CFB (coated front and back) sheets. The coatings of the back of the CB sheet, of the front and back of the CFB sheets if any, and of the front of the CF sheet contain materials that when brought into association with each other develop a coloured image.
When the front of the CB sheet is typed on or otherwise pressure imaged, material is transferred between the back of one sheet and the front of the next through the set to give rise to the copies required. Usually, a solution of a dye precursor or "colour former" carried on the sheet as isolated droplets each confined within a pressure rupturable barrier is transferred from the back of one sheet to the front of the next after rupture of the barrier by the applied pressure, and interacts with a "colour developer" present there to give the image.
All of this is very well known and requires no detailed description.
PIGMENT IN CB-SHEET FRONT COATINGS
The present invention has arisen from a requirement, in the highest grade products, for a pigment-containing coating on the front face of CB sheets, improving them in appearance and in printability.
THE INVENTION
The invention provides record material comprising a paper sheet having on its front a printable pigment coating and on its back isolated droplets of colour former solution each confined within a pressure rupturable barrier, wherein the pigment coating comprises a binder for the pigment together with a synthetic reactive sizing agent or a coating structure agent or both. The sizing agent is for example an alkyl ketene dimer, alkenyl succinic anhydride, or other neutral reactive size. Another example is a polyurethane size. The coating structure agent is for example a carboxy methyl cellulose, a soya or other protein, an alginate, or other hydrophilic polymer. The relative amounts of components in the coating are desirably by weight 60-95 parts pigment, 10-30 parts binder, 0.5-10 parts size where present and 0.5-5 parts coating structure agent where present. Binder may however be lower, for example down to 5 parts. In options within these ranges, pigment, binder and size are respectively 60-95 parts, 16-22 parts and 0.5-10 parts or pigment, binder and coating structure agent are respectively 75-85 parts, 12-22 parts and 0.5 to 5 parts, with in the latter case optionally 1-5 parts size being present also. Where the coating structure agent is present without size, specific ranges are 75-82 parts pigment, and 15-22 parts binder.
The coating mixes themselves, besides their use, are new and an aspect of the invention as, specifically, are:
A. Multiple form sets each comprising a CB sheet, a CF sheet and optionally one or more CFB sheets, and carrying an edge padding adhesive to join the sheets within the sets and the sets to each other, wherein the CB sheet is of the record material as above, the sizing agent being present to enable the sets to be fanned apart without separation of the sheets within the sets.
B. A method of making a record material comprising a paper sheet having on its front a printable pigment coating and on its back isolated droplets of colour former solution each confined within a pressure rupturable barrier, wherein the paper sheet is coated with a mix containing a binder for the pigment together with a synthetic reactive sizing agent or a coating structure agent, or both the sizing agent and the coating structure agent, in an aqueous medium at 25-75% advantageously 50-65% solids by weight of the mix; is dried to give a coated sheet of Bendtsen porosity 25 to 30 ml/min or more; and is coated on the back at 400 to 450 m/min or more with a colour former coating formulation to give said record material.
C. A method of making multiple form sets each comprising a CB sheet, a CF sheet a
REFERENCES:
patent: 3931422 (1976-01-01), Bateman et al.
patent: 4041193 (1977-08-01), Hayashi et al.
patent: 4335184 (1982-06-01), Miyamoto et al.
patent: 4397483 (1983-08-01), Hiraishi et al.
patent: 4567496 (1986-01-01), Ogata et al.
Clay Kevin J.
Cooper John B.
Hess Bruce H.
The Wiggins Teape Group Limited
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