US2188590A - Nonsmudging transfer sheet - Google Patents

Description

Jan. 30, 1940.' J. BJQRKSTEN 'ET Al. y 2,188,590

NONSMUDGING TRANSFER SHEET;`

Filed Feb. 4. 1938 ...Patented Jan. 30, 1940 i .o

UNITED iSTATES PATENT OFFICE I Incorporated, Ghicago, Ill.,` a corporation of West Virginia/f' .-1 imitation rebusry 4.1938, serial No. 188,107 schim. (ci. zzz-2s) This invention relates to transfer sheets, yand of the keys of a typewriter as shown in Fig. 2, more particularly to nonsmudging impression portions of the resin and the underlying comtype transfer sheets. It includes transfer sheets position will be detached together from the coatsuch as carbon paper, typewriter ribbon, and ing to form an imprint on the contacting sheet,

5 the like, which are coated with a composition as shown in Fig. 3, and will be firmly secured to v5 which is transferable to a contacting surface by Said sheet by means 0f the resin. v the application of pressure or impact such as may It has been discovered that natural and synbe produced by a pencil or the keys of a typethetic resins which are of high enough molecuwriter. These impression type transfer sheets lar weight to be frangible nonsmearing solids but l0 may generally be divided into three classes; (l) of not such high molecular weight asto form 10 transfer sheets such as ordinary carbon paper, tough, self-sustaining lms of the nature of rub- `Which contain a pigment; (2) transfer sheets ber or nitrocellulose are in general most suitable such as hectograph carbon paper which contain yfor forming the smudge PrOOf film Coating 0f this a soluble dye, and (3) .tranfer sheets such as invention. 18 printing process carbon paper, which contain a However, these resins also must be soluble in 5 waxy or oily ink absorbent material, solvents which are not solvents for the under- An object of this invention is to provide e lying transfer composition, and not soluble in smudge proof impression type transfer sheet any of the constituents of the underlying transwhich is capable of forming clear and adherent fer COmPOSitiOn- 20 impressions. When the transfer composition, for example, 20

Another object is to provide a smudgeproof consists mainly of an alcohol or water soluble transfer sheet of the type which contains a soldye, the resin to be used for the protective coatuble dye, and is suitable for spirit process or ing should be insoluble in water or alcohol. For heotograph use. example, if the dye is crystal or methyl violet or A further object is to provide e, smudgeproof fuchsine, then the following solvents would be 25 transfer sheet of the type which contains waxy suitable for application of the coating resin: caror oily ink absorbent material, and which is suit.. bon tetrachloride, benzol, isopropyl ether.

able for making impressions which may be re- Particularly suitable as materials for protecinked, tive coatings or transfer sheets containing water 8. other-.objects and features of this invention or a1coh01 soluble dyestuffs. arethe alkyd resins. 3 will become apparent es the following detailed the highly chlorinated rubber resins, the solid description progresses, reference being had to cumaroneindene resins `and cyclized rubber resins l the accompanying drawing, in which; obtained from rubber by reacting the rubber in Fig, 1 is an enlarged sectional view of the solution with `an amphoteric metal halide or I5 smudgeproof transfer sheet, chlorostannic acid and isolating the end product. 35

Fig. 2 is a detailed sectional view showing the To prevent excessive hardening of the applied invention applied to typewriter operation. coating, it is generallyadvisable to include in the Fig. 3 is an enlarged detail sectional view of an coating solution small amounts of plasticizers.A impression produced from the transfer sheet of For example. Castor Oil. Stealc Reid. Dara-m11 Wax. 40 Fig. 1 cna master sheet. or any other non-drying substance which pre- 40 Referring to the drawing in which an embodivent the resinous coating from becoming too ment of the invention is shown, reference charhard. acter l designates a base sheet such as tissue Examples of suitable coating formula. are given paper or other sheet material having thereon a below:

ltransfer coating 2 of a soluble dye or of an ole- 1 Preferred formulae 45 aginous composition depending on the application of the invention, and having a-smudge proof Femm wmptm layer 3 over said coating 2.

In the preferred embodiment of the invention 'l 2V 3 n 5o the smudge proof layer 3 comprises a reslmpreierably in combination with a plasticizer, and is mzegfxt, bis' 35 LB v. g1g of such friability, strength, and adhesive power Chmn glia--h-l-H -r-L 0.2 0-2 0.2 that when the transfer sheet is used with a cone'oivent{2,'e c n 98 ';g' tacting sheet l for duplicating in the usual pres# ISO propyiether 50 sure or impact manner. as for example by means I l 55 In the above formulae Petrex No. 1 is the trade name of a product of Hercules Powder Co. More particularly, it is a modified alkyd resin made from polybasic acids of the alicyclic series.'

Other suitable formulae Resin 1.8 1 6.2 Dulux R-C-l 2 Carbon tetrachloride 98 99 98 98 98 47 Solvent Femme 98 98 Iso propyl ether In the above formulae the following trade names are used.

Amberlac D-96--Made by Resinous Products & Chemical Company. Melting range -90 C.-a modified alkyde resin-a light amber solid resin.

Neville R-10 Hard Resin-Made by Neville Co.-Coumarone indene resin-light amber solid resin. Melting range 13D-150 C.

Dulux R-C-l-Made by E. I. du Pont deber in solution with an amphoteric metal halideA or chlorstannic acid, and isolating the resulting cyclized rubber. A brittle resin. Sometimes called a condensation derivative of rubber, particularly in the Goodyear patents. See viz. U. S. Patent 2,052,391.

Method of application of the above formulae:

Any of the above preparations may be applied in any convenient manner so that after evaporation of the solvent a thin lm remains covering the material treated. Generally, it is preferred to dip the carbon sheet, ribbon, etc., into the solution, withdraw it after a few seconds and to dry it by means known to the art. In a wann air current the drying is well-nigh instantaneous.

The resinous protective coatings are particularly suitable for dye-carrying impression type transfer sheets and such resin protected transfer sheets oier some very important advantages in liquid or direct process duplication. In that method a dye carrying master" sheet is prepared by typing or writing on a sheet of suitable paper against a dye carrying impression yielding sheet, so that a design in reverse is produced on the back of the master sheet. This master sheet is then by mechanical means repeatedly brought to contact copy papers, which have been previously moistened with a volatile dye-solvent, so that dye from the impressions on the master sheet is transferred to the solvent moistened copy sheets, in such manner that copies are produced of the matter written on the master sheet. By this process several hundred readable copies may be obtained, but after -250. copies the master sheet becomes moistened with dye solvent, which partially dissolves some of the dye at the base of the dye carrying impressions on the master sheet, causing these to spread out ,and smudge, whereby the copies are. greatly impaired.

This is particularly objectionable when a comparatively less volatile solvent is used, such as for example water. to which may have been added a surface tension reducing agent to assist in spreading of the solvent.

However, when a protective coating is employed, according to this invention, the base of the dye carrying impression on the master sheet consists of the material of this protective coating as shown in Fig. 3; Since this coating material would generally be insoluble in all solvents used or contemplated for liquid process duplication, it prevents access of the solvent to the dye,

v and consequently also prevents such deterioration of the master imprint as usually occurs after 150-250 copies due to deterioration of the dye.

Resinous protective coatings may also be applied to other impression type transfer sheets than those carrying dye stuffs. However, when the transfer composition contains an oleaginous or waxy material, it is necessary to use resins which are soluble in a solvent which does not appreciably dissolve or soften the oleaginous or waxy materials. One type of transfer sheet which is particularly important at the present date is the so-called printing process carbon paper. This is a carbon paper which contains no pigment and which may or may not contain a dye stuff. Its essential ingredient is a soft oily or waxy material which is transferable to a contacting surface by the application of pressure or v impact such as may be produced by a pencil or a typewriter, and which gives an imprint on the contacting surface which is adherent and highly ink-absorbent. These printing process transfer sheets, however, are so sensitive to pressure and impact that they tend to give imprints from other causes than the impact of the keys of the typewriter. Such other causes are, for example, a casual pressure from the operator's hands or a. pressure from the roller of the typewriter. When the copy obtained is used as means of ink transfer in a printing process all such non-intentional impressions will also become inked, and cause ink or smudge on the copy sheets.

As far as is known, printing process carbon papers have not hitherto been made which.are substantially smudge proof.

In accordance with this invention printing process carbon papers are coated with a protective coating of a resin which is applied dissolved in a solvent which does not dissolve the oleaginous material of the transfer compositions.

'Ihe following example will illustrate the invention as applied to printing process carbon paper:

In coating the printing process transfer sheet a .2% solution of shellac in ethyl alcohol is spread over the transfer sheet, and the solvent subsequently evaporated at a temperature lower than the melting point of the transfer coating.

While there have been shown and described certain forms of the invention, it is to be understood that it is capable of many modifications. Changes, therefore, may be made without departing from the spirit and scope of the invention as described in the appended claims, in which it is the intention to claim all novelty inherent in the invention as broadly as possible, in view of the prior art.

We claim:

1. ,A transfer medium adapted for use with a pressure or impact instrumentality such as a pencil or the keys of a typewriterv comprising a base coated with a pressure or impact transferable composition, and a ilm essentially com.

- prising resin coated on said transfer composition,

said nlm being of such character that it will break and be transferred to a contacting sheet with the transfer composition when pressure or impact is applied to the transfer sheet by a pencil or the keys of a typewriter in the usual manner, of such adhesive character that it will adhere to the contacting sheet and to said base transfer composition, of such solubility that it will dissolve in solvents which are not solvents for the base transfercomposition.

2. A transfer medium adapted for use with a pressure or impact instrumentality such as a. pencil or the keys of a typewriter comprising a base coated with a pressure or impact transferable composition, and a film essentially comprising resin coated on said transfer compositionA said film being of such character that it will break and -be transferred to a contacting sheet with the transfer composition when pressure or impact is applied to the transfer sheet by a pencil or the keys of a typewriter in the usual manner,

of such adhesive character that it will adhere to the contacting sheet and to said base transfer composition, of such solubility that it will dissolve in solvents which are not solvents for the base transfer composition, the resin of said lm being of the class of natural and synthetic resins which are of sufficiently high molecular weight to be frangible non-smearing solids.

3. A transfer medium adapted for use with a pressure or impact instrumentality such as a pencil or the keys of a typewriter comprising a base coated with a pressure or impact transferable composition and a pressure or impact transferable film essentially comprising an alkyd resin, coated on said transfer composition.

4. A transfer medium adapted for use with a pressure or impact instrumentality such as a pencil or the keys of a typewriter comprising a base coated with a pressure or impact transferable composition and a pressure or impact transferable lm essentially comprising a chlorinated rubber coated on said transfer composition.

5. A transfer medium adapted for use with a pressure or impact instrumentality such as a pencil or the keys of a typewriter comprising a -base coated with a pressure or impact transferable composition and a pressure or impact transferable lm essentially comprising a condensation derivative of rubber coated on said transfer composition.

6. A transfer medium adapted for use with a pressure or impact instrumentality such as a pencil or the keys of a typewriter comprising a base coated with a pressure or impact transferable composition, containing soluble dye, and a film essentially comprising resin coated on said transfer composition, said nlm being of such character that it will break and be transferred to a contacting sheet with the transfer composition when pressure or impact is applied in the usual manner, of such adhesive character that it will adhereto the contacting sheet and to said base transfer composition, of such solubility that it will dissolve in solvents which are not solvents for the base transfer composition.

7. A transfer medium adapted for use with a pressure or impact instrumentality such as a pencil or thev keys of a typewriter to produce reinkable impressionpn a contacting sheet, said transfer medium comprising a base coated with a pressure or yimpact transferable composition containing a waxy or oily ink absorbent material, and a film essentially comprising resin coated on said transfer composition, said film being of such character that it will break and be transferred to a contacting sheet With-the transfer composition when pressure or impact is applied in the usual manner, of such adhesive character that it will adhere to the -contacting sheet and to said base transfer composition, of such solubility that it will dissolve in solvents which are not solvents for the base transfer composition.

8. A transfer sheet designed for use in a typewriter to produce reinkable oleaginous impressions on a contacting sheet, said transfer sheet having a substantially pigment free oleaginous coating and a pressire or impact transferable coating on said first coating comprising shellac.

9. A transfer medium adapted for use with a pressure or impact instrumentality such as a pencil or the keys of a typewriter to produce reinkabie impressions on a contacting sheet, said transfer medium comprising a base coated with a pressure or impact transferable composition containing a waxy or oily ink absorbent material, and a film layer comprising primarily a resin and a plasticizer on said transfer composition, the resin being present in such amount as to secure substantially increased adhesiveness as compared to the oily or oleaginous material of the first coating, and the plasticizer being present in such amount as to render the second coating transferable with the first coating by pressure or impact.

JOHAN BJORKSTEN. WILLIAM J. CHAMPION

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