Clay-coated record material of improved image durability

Claim 2

Record material for forming a colored image of improved resistance to fading on imagewise contact with an image-forming material consisting essentially of an electron-donating colorless dye precursor compound, comprising a support carrying a uniform even distribution throughout a recording area thereof of a multitude of finely divided particles of a clay consisting essentially of at least about 15% by weight of montmorillonite clay mineral having an expanding three-layer lattice molecular structure exhibiting when analyzed in the presence of benzyl ether of Michler's hydrol by X-ray diffraction at least a discernible peak at a 2 θ value of 5.6-5.7, a sufficient proportion of said molecular structure having been irreversibly chemically altered to impart substantially Newtonian viscosity behavior to an aqueous suspension containing at least about 15% by weight of said clay particles.

Claim 3

Record material as in claim 1 wherein said clay contains up to about 80% of a non-montmorillonite clay.

Claim 4

Record material as in claim 1 wherein said montmorillonite clay molecular structure is irreversibly altered by treatment of the clay with an acid followed by substantial removal of said acid and acid salts from the clay.

Claim 5

Record material as in claim 3 wherein said acid treatment is sufficient to increase the hydrated silica value and decrease the alumina content of the clay by at least about 2-3% by weight relative to the untreated clay.

Claim 6

Record material as in claim 3 wherein said clay has an acidity equivalent to not more than about 1.5 mg/KOH per 5 gms clay.

Claim 7

Record material as in claim 1 wherein said clay is present on said support as a thin uniform layer of said clay particles having a weight of about 2-12 gm/sq.m.

Claim 8

A pressure sensitive record system having improved resistance to fading comprising a manifold set of at least one transfer sheet and at least one receiving sheet, said transfer sheet carrying on at least a portion of the surface thereof in an insulated pressure-releasable state a solution of image-forming material consisting essentially of an electron-donating organic dye precursor adapted to produce color on contact with an electron-acceptor solid, and said receiving sheet carrying on at least a corresponding8c area of an adjacent surface a uniform even distribution of a multitude of finely divided particles of a clay consisting essentially of at least about 15% by weight of montmorillonite clay mineral having an expanding three-layer lattice molecular structure exhibiting when analyzed in the presence of benzyl ether of Michler's hydrol by X-ray diffraction at least a discernible peak at a 2 θ value of 5.6-5.7, a sufficient proportion of said molecular structure having been irreversibly chemically altered to impart substantially Newtonian viscosity behavior to an aqueous suspension containing at least about 15% by weight of said clay particles.

Claim 9

A pressure sensitive record system having improved resistance to fading comprising a manifold set of at least one transfer sheet and at least one receiving sheet, said transfer sheet carrying on at least a portion of the surface thereof in an insulated pressure-releasable state a solution of image-forming material consisting essentially of an electron-donating organic dye precursor adapted to produce color on contact with an electron-acceptor solid, and said receiving sheet carrying on at least a corresponding8c area of an adjacent surface a uniform even distribution of a multitude of finely divided particles of a clay consisting essentially of at least about 15% by weight of montmorillonite clay mineral having an expanding three-layer lattice molecular structure exhibiting when analyzed in the presence of benzyl ether of Michler's hydrol by X-ray diffraction at least a discernible peak at a 2 θ value of 5.6-5.7, a sufficient proportion of said molecular structure having been irreversibly chemically altered to impart substantially Newtonian viscosity behavior to an aqueous suspension containing at least about 15% by weight of said clay particles.

Claim 10

The record system of claim 7 wherein said dye precursor solution is contained in microcapsules forming a layer on said transfer sheet.

Claim 11

The record system of claim 8 wherein said microcapsule layer is applied at a weight of about 1-12 gms/sq.m.

Claim 12

The record system of claim 7 wherein said dye precursor is dissolved in an oily solvent of low volatility.

Claim 13

The record system of claim 10 wherein said oily solvent has a boiling point of at least about 200°C.

Claim 14

The record system of claim 7 wherein said montmorillonite clay is chemically altered by treatment with an acid and has a residual acidity equivalent to not more than about 1.5 mg/KOH per 5 gms clay.

Claim 15

The record system of claim 7 wherein said receiving sheet has on the surface thereof a thin uniform even layer of clay particles having a weight of about 2-12 gm/sq.m.

Claim 16

The record system of claim 7 wherein said precursor is present in said solution in a concentration of about 1.5-5% by weight.

Claim 17

A pressure-sensitive self-contained image-producing record material having improved resistance to fading comprising a sheet support having on one side thereof finely divided liquid inclusions of a solution of an organic dye precursor maintained in an isolated pressure-releasable condition, said precursor consisting essentially of an electron-donating compound adapted to produce color on contact with an electron-acceptor solid, and on the same side of said support a uniform even distribution of a multitude of finely divided particles of a clay consisting essentially of at least about 15% by weight of montmorillonite clay mineral having an expanding three-layer lattice molecular structure exhibiting when analyzed in the presence of benzyl ether of Michler's hydrol by X-ray diffraction at least a discernible peak at a 2 θ value of 5.6-5.7, a sufficient proportion of said molecular structure having been irreversibly chemically altered to impart substantially Newtonian viscosity behavior to an aqueous suspension containing at least about 15% by weight of said clay particles.

Claim 18

A pressure-sensitive self-contained image-producing record material having improved resistance to fading comprising a sheet support having on one side thereof finely divided liquid inclusions of a solution of an organic dye precursor maintained in an isolated pressure-releasable condition, said precursor consisting essentially of an electron-donating compound adapted to produce color on contact with an electron-acceptor solid, and on the same side of said support a uniform even distribution of a multitude of finely divided particles of a clay consisting essentially of at least about 15% by weight of montmorillonite clay mineral having an expanding three-layer lattice molecular structure exhibiting when analyzed in the presence of benzyl ether of Michler's hydrol by X-ray diffraction at least a discernible peak at a 2 θ value of 5.6-5.7, a sufficient proportion of said molecular structure having been irreversibly chemically altered to impart substantially Newtonian viscosity behavior to an aqueous suspension containing at least about 15% by weight of said clay particles.

Claim 19

The record material of claim 15 wherein said liquid incursions of said precursor solution are contained within microcapsules.

Claim 20

The record material of claim 15 wherein said precursor is present in said solution in a concentration of about 1.5-5% by weight.

Claim 23

The method of claim 18 wherein said clay dispersion is coated as a thin uniform even layer on said web or sheet surface.

Claim 24

The method of claim 19 wherein said clay dispersion has a concentration of clay solids of about 30-45% by weight.

Claim 25

The method of claim 20 wherein all of said clay solids is constituted by acid-treated montmorillonite clay.

Claim 26

The method of claim 18 wherein said clay is dispersed in said aqueous medium in the absence of significant amounts of non-volatile dispersing agents.

Claim 27

The method of claim 18 wherein said acid-treating clay is mixed with a non-montmorillonite clay in proportions of montmorillonite to non-montmorillonite clay of up to 1:4 by weight before being applied to said web or sheet.

Claim 28

The method of claim 18 wherein, prior to dispersing said clay, the acid and acid by-products are substantially removed therefrom.

Claim 31

The method of claim 25 wherein said colorless dye precursor compound is of a diphenyl- or triphenylmethane dye.