US3416942A - Direct-transfer copy sheet - Google Patents

Description

Dec. 17, 1968 w. scHurzNER E-rAx. 3,416,942

DIRECT-TRANSFER COPY SHEET Filed June 12, 1967 (and/or Sulfonae or v Nonionic Deergenf) Waler Schzner Franz Mock 'INVENTORS BY s 1w-gw Attorney United States Patent 3,416,942 DIRECT-TRANSFER COPY SHEET Walter Schutzner and Franz Mock, Vienna, Austria, as-

si nors to W. Koreslta, Vienna, Austria, a corporation o Austria Continuation-impart of application Ser. No. 500,187, Oct. 21, 1965. This application June 12, 1967, Ser. No. 645,265 Claims priority, application Austria, Oct. 11, 1961, 7,624/61; Jan. 31, 1962, 809/62; Feb. 1, 1962, 850/62 12 Claims. (Ci. 1l7-36.3)

ABSTRACT OF DISCLOSURE A direct-transfer copy sheet having an under surface constituting a color-transfer layer and consisting of a pigment dispersed in a matrix of waxy material or of a blushed celluloslc or polymeric material, and a color'- receiving layer upon the other side of the substrate adapted to preferentially receive pigment from a similar colortransfer layer of an overlying sheet, the color-receiving layer consisting of a waxy matrix containing one or more surface-active agents facilitating absorption of writing inks by the color-receiving layer and selectedfrom the group of water-free wax-dispersiblc surface-active agents such as stearic acid amides and alkali-metal salts of stearic and other fatty acids, alkylaryl sulfates or sulfonates, and polyglycol ethers or esters.

This application is a oontinuation-in-part of our copending application Ser. No. 500.187 filed Oct. 21, 1965, now abandoned, which, in tum, is a continuation-impart of our earlier application Ser. No. 229,235, tiled Oct. 8, 1962, since issued as U.S. Patent No. 3,243,312 of Mar. 29, 1966.

Our present invention relates to a direct-copy sheet wherein a fiat flexible substrate, generally of paper, is provided with a color-receiving layer adapted to cooperate with a color-transfer layer on another sheet placed thereon in layer-to-layer contact; upon the exertion of writing pressure (by pen, pencil or typewriter) on the reverse side of the sheet bearing the transfer layer, coloring pigment is released from this layer onto the receiving layer of the adjoining sheet to form a visible trace of the written or printed message.

The recent development of transfer layers for the purpose described has made it possible to hold the color pigments so firmly bound within such layers that they will not be released onto an untreated surface, e.g. that of normal writing paper, even under heavy copying pressure. The copy sheet designed to receive a message must then be specially prepared by having a waxy matrix applied to a surface thereof.

A disadvantage of conventional color-receiving layers with waxy matrices is their inability to accept printing, ballpoint and other inks so that copies made thereon cannot be readily corrected or annotated except with the interposition of a transfer sheet which is often inconvenient.

It is, therefore, the general object of our present invention to provide an improved color-receiving layer, of the general character and for the purpose set forth, which can also be used for direct writing.

Surprisingly, in accordance with this improvement, we have found that the aforestated object can be realised by the incorporation of one or more surfactants in the axy matrix of the receiving layer, specifically surfactants w ich are salts of a long-chain fatty acid or those enumerated below. These salts particularly include the heavy-metal soaps, although other compounds such as amides or esters of these fatty acids could also be used. Since these derivatives of long-chain fatty acids are generally regarded as 3,416,942 Patented Dec. 17, 1968 oleophobic, their effectiveness in facilitating the absorp-y tion of inks (including oil-base uids) by a waxy layer was completely unexpected.

As stearic acid is the most readily available fatty ucid of the class referred to, its compounds are preferentially used although homologues thereof are equally suitable.

The long-chain surfactants employed in accordance with this invention may also be used together with or replaced by certain other surface-active agents such as alkylaryl sulfonates, fatty alcohol sulfonates and nonionic detergents (e.g. polyglycol and polyethylene glycol ethers and esters).

Thus it is an essential feature of this invention that the surface-active component be selected from the group of wax-soluble, oil-soluble (preferably nonaqueous), alkylaryl or fatty-alcohol sulfates and sulfonates, potassium palminate, stearic-acid amides, and polygylcol esters and ethers, individually or in combination.

Color-receiving layers of the character described may be used with a wide variety of color-transfer layers. Typical among such transfer layers are those which comprise a pigment-permeated binder of waxy, cellulosic or polyvinylic (e.g. polystyrene) material. Particularly in the case of a cellulosic binder consisting of a cellulose derivative soluble in an organic medium, it is possible to have the pigment present in the form of a so-called blush coating." obtained by admixing a higher-boiling liquid, in which the cellulose derivative (e.g.cthyl cellulose) is insoluble, with the organic solvent for the binder and dissolving the binder in the mixture to which the coloring agent or pigment is also added. Upon subsequent deposition of this mass on a substrate, the solvent evaporatcs first and the binder is precipitated out of the nonsolvent liquid, together with the pigment, in the form of a whitish deposit.

In the following examples we shall separately describe a variety of color-transfer layers and a variety of colorreceiving layers according to the invention, it being understood that any one of the receiving layers is compatible with any of the transfer layers.

The sole figure of the drawing is a cross-sectional view, in diagrammatic and greatly enlarged form, illustrating a direct-transfer copy sheet according to this invention.

In the drawing, we show an upper color-transfer layer 10, containing a pigment in a matrix of wax/high polymer or a blushed coat of cellulosic or polymeric material, on a fiber substrate 11. The underside of the latter is provided with a color-receiving layer 12 consisting of a wax and the surfactant.

(A) TRANSFER LAYER Example I 81% trichloroethylene solvent is deposited upon a fiat flexible substrate (e.g. paper) and dried to produce a deposit of about 5.6 grams/m?. The sheet is also provided, on its upper surface, with a wax layer (5 grams/m?) of ozocerite which is deposited thereon from a melt and has a softening point of about C. The resulting colortransfer layer readily deposits its color pigment upon the upper surface of an identical underlying sheet and pro duces sharp, smudge-free copy.

We have found that in addition to stearin the following substances are also suitable for incorporation along or in admixture with one of the others in the color-transfer layer: cetyl alcohol, crude montan waxes, earnauba wax, KP wax of the type produced by the firm Farbwerke Hchst, candelilla wax and various other commonly available waxes. In cases in which the wax is insufiiciently soluble in the cold solvents, the latter may be heatedto a temperature of, say 60-70 C. to accomplish solution.

Example Il The rear surface of a paper substrate is treated with 8 mixture consisting by weight of substantially 6% polyvinyl acetate, 10% crude montan wax, 15% graphite pigment and 69% toluene, the layer being then dried to a thickness of about 5-6 grams/m?. Then the montan wax is only slightly soluble in the toluene solvent at room temperature, the mixture is heated to a temperature of about 70 C. in order to facilitate its dissolution. The front side of the sheet is provided, as before, with a ccresin-wax layer of about 5 grams/m?.

Example Ill A color-transfer layer of relatively clear appearance but having the copying capabilities of those of Examples I and Il is provided by admixing 5%, by weight, ethylcellulose (e.g. that marketed by Hercules Powder Company, :is N l") with 15% pulverulent graphite pigment and acetone solvent for the ethyicellulose in an amount constituting 67% of the mixture. To this is added 13% water which serves as a liquid vehicle for the ethylcellulose, The mixture is deposited upon the rear surface of a paper sheet and dried to produce a layer of about -6 grams/ m3 which, owing to the small particle size of the cellulosic matrix, is lightcolored but nevertheless yields sharp copy when employed in conjunction with a sheet whose front side is provided with a layer of ceresin wax of about 5 grams/m?. Chiorinated polyvinyl chloride may be substituted for the ethylcellulose if trichloroethylene and gasoline are substituted for the acetone and water.

Example IV Example V in a manner similar to that of Example 1V, a colortransfer layer is produced from a mixture of 5 parts by weight of ethylcellulose, 20 parts by weight of graphite, 5 parts by weight of titanium-white masking pigment, 60 parts by weight of acetone and parts by weight of water.

Example VI A similar color-transfer layer is formed from 5 parts of ethylcellulose, parts of graphite, 3 parts of finely divided silicic acid (e.g. that manufactured under the name Acrosil by the firm Degussa), 60 parts acetone and 10 parts water, all parts by weight.

Example VII Another color-transfer layer is produced by depositing a mixture consisting substantially, by weight, of 5 parts of chlorinated polyvinyl chloride (e.g. of the type marketed by the Nobel Dynamite Company under the trademark Rhenoex), 5 parts of carbon-black color-transfer pigment (e.g. the pigment designated Carbon Black 403 by Degussa), 15 parts kaolin, 60 parts methylene chloride solvent for the synthetic resin, and 10 parts of gasoline having a boiling-point rango between 90` and 120 C.. upon the rear side of a paper sheet. This color-transfer lnyer is used in conjunction with a ceresin-wax layer pmpared as previously described.

Example VIII A color-transfer layer for red copies is provided by compounding 5 parts by weight of ethylcellulose with 5 parts of lithol-red pigment (e.g. of the highly comminuted type produced by BASF under the trademark RMT), 10 parts of kaolin, 60 parts of acetone, and lO parts of water and depositing same upon a sheet to yield a layer of about 5-6 grams/m?.

Example 1X Another suitable color-transfer layer is formed by drying a layer composed, in parts by weight, of 5 parts 0f chlorinated polyvinyl chloride, 15 parts of graphite, 5 parts of carbonate of lime, 5 parts of kaoline, 60 parts of methylene chloride and 10 parts of gasoline having a boiling-point range of 90-120 C.

Example X 7 parts by weight of poiyvinylchloride acetate (Vinylite VYNi-i-l, produced by Union Carbon Corp), 14 parts of zinc stearate and 12 parts of paraiiin are dissolved in 250 parts of trichloroethylene which may be heated to expedite the dissolving process. The solution is admixed with 2 parts of carbon black and 65 parts of kaolin, the resulting mass being then comminuted for about 6 hours in a ball mill. instead of the 7 parts of Vinylite, 8 parts of ethylcellulose (N 100, by Hercules Powder Co.) may be used in the above mixture.

Example X I The procedure of Example X is followed, but the 14 parts of zinc stearato are replaced by 30 parts of lead stcarate, with an increase in the amount of carbon black from 2 parts to 6 parts by weight.

(B) RECEIVING LAYER Example X II The upper surfaces of any of the sheets described in accordance with Examples I-XI may be provided with a wax layer consisting, substantially, of 30 parts by weight of zinc stearate, 67 parts by weight of paraffin and 3 parts by weight of Aerosil. The stearate and paraffin are melted together and deposited from the melt onto a support paper after the Aerosil is added. The resulting layer of about 3 grams/m.2 can be written upon by ball-point pens and is a color acceptor yielding unobjectionable copy.

Example X Ill Another wax layer may be provided by melting 70 parts by weight of ozocerite (ceresin wax) together with 30 pans by. weight of lead stearato and then coating a substrate with this melt to yield a layer of 3 grams/m?. A paper thus treated can be printed in the usual manner with the printing inks drying at normalrates.

Example X I V A wax surface compatible with writing inks may be provided by depositing from the melt a mixture of 65 parts by weight of paran and 35 parts by weight of a monoethanolamide of stearic acid to yield a layer of 3 grams/m?.

Example X V A melt consisting of 34 parts by weight of ozocerite, 33 parts by weight lead stearate and 33 parts by weight of the monoethanolamide of stearic acid is deposited upon a sheet as previously described. The resulting paper can be printed in a conventional process with the inks drying at normal speed and can be written upon with both ballpoint and fountain-pen inks.

Example X Vl A receiving layer compatible with the transfer layers of Examples I-XI is prepared by dissolving 15% by weight of potassium palmitate in a melt of ozocerite by weight) and then coating the resulting melt onto the face of a copy-transfer sheet as previously described. Re-

stilts were similar to those obtained in Examples XIV and XV.

Example XVII A receiving layer compatible with the transfer layers of Examples I-XI is prepared by dissolving 5% by weight of the fatty alcohol polyglycol ether Emulphor AF and 15% by weight of lead stearate in a melt of ceresin wax (80% by weight) and then coating the resulting melt onto the face of a copy-transfer sheet as previously described. Results were similar to those obtained in Examples XIV and XV.

Example XVIII A receiving layer compatible with the transfer layers of Examples I-XI is prepared by distributing 15% by weight kaolin and 5% by weight of the lauryl alcohol sulfate marketed under the name Cyclopon Pulber WN 85 in a paraffin melt (80% by weight) and following the procedure of Examples XVI and XVII.

The salts of long-chain fatty acids set forth in Examples XII, XIII and XV, and other compounds of the same class, have the character of slow-acting drying agents for printing inks, their siccative action being sufficiently delayed to permit penetration of the matrix by the ink.

The presence of a silicon compound (Example XII) in the receiving layer gives it a slightly abrasive character which facilitates writing by ball-pointv pens. Such an abrasive additive, of course, can be included in any of the other receiving layers described.

The susceptibility of the receiving layer especially to aqueous inks, and the continuity and uniformity of theirr v tracings, can be further improved by the admixture therewith of, say one part by weight of a nonionic detergent such as the nonylphenylether of polyethyleneglycol or the fatty alcohol polyglycol ether Emulphor AF or .lauryl alcohol sulfate of a sulfonate-type detergent such as ethylbenzene sulfonate or stearol sulfonate. Furthermore, these surfactants need not be used with the stearic-acid amide but can be substituted therefor. These detergents are likewise compatible with any one of the receiving layers described in Examples XII-XV. Other suitable wetting agents are water-soluble soaps, such as the alkali-metal salts of fatty acids (e.g. sodium stearate).

Although each of the transfer layers of Examples I,XI can be used in combination with any of the receiving layers of Examples XII-XV, with or without the modifications indicated above, we have found that the most effective transfer occurs from a layer of the type in Examples I, II, X and XI, i.e. wherein the binder is a mixture of wax and a vinylic polymer.

We claim: l

l. A direct-transfer copy sheet comprising a fiat flexible substrate having a color-transfer layer on one surface thereof and a color-receiving layer on the other suface thereof for co-operation with the color-transfer layer of another similar sheet adapted to release preferentially ad- Ltering pigment to a waxy surface, said color-receiving layer consisting essentially of a major proportion of a waxy matrix having distributed therein a minor proportion, sufficient to facilitate the acceptance of writing inks by said waxy matrix, of at least one wax-dispersible surface-active agent from the group which consists of alkalimetal fatty acid soaps and fatty acid amides, alkylaryl and fatty-alcohol sulfonates and sulfates, and polyglycol ethers and esters.

2. The direct-transfer copy sheet defined in claim 1 wherein said surface-active agent is a stearic acid amide.

3. The direct-transfer copy sheet defined in claim 1 wherein said surface-active agent is potassium palmitate.

4. The direct-transfer copy sheet defined in claim 1 wherein said surface-active agent is a fatty-alcohol polyglycol ether.

5. The directtransfer copy sheet defined in claim 1 wherein said surface-active agent is lauryl alcohol sulfate.

6. The directtransfer copy sheet defined in claim 1 wherein said color-transfer layer consists of a pigmentpermeated binder selected from the group which consists of waxlike substances, blushed cellulosic substances and polymeric substances.

7. The direct-transfer copy sheet defined in claim 6 wherein said color-receiving layer consists essentially of parts by weight of paraffin and 3S parts by weight of stearic acid monethanolamide.

8. The direct-transfer copy sheet defined in claim 6 wherein said color-receiving layer consists essentially of substantially equal proportions of ozocerite, lead stearate and stearic acid monoethanolamide.

9. The direct-transfer copy sheet defined in claim 6 wherein said color-receiving layer consists essentially of 85% by weight of ozocerite and 15% by weight of potassium palmitate.

l0. The direct-transfer copy sheet defined in claim 6 wherein said colorreceiving layer consists essentially of by weight of ceresin wax, 15% by weight of lead stearate and 5% by weight of fatty-alcohol polyglycol ether.

1l. The direct-transfer copy sheet defined in claim 6 wherein said color-receiving layer consists essentially of 80% by weight of paraffin, 15% by weight of kaolin and 5% by weight of lauryl alcohol sulfate.

12. The direct-transfer copy sheet defined in claim 6 wherein said color-receiving layer contains a minor proportion of an inorganic abrasive substance.

References Cited UNITED STATES PATENTS 2,872,340 2/1959 Newman et ai 117--36.1 3,029,157 4/ 1962 Sutheim et al 117-3 6.1 3,151,550 10/1964 Newman 1l7-36.1 3,243,312 3/1966 Schutzner et al. 11736.3

MURRAY KATZ, Primary Examiner.

U.S. Cl. X.R.

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