US2610921A - Transfer ink - Google Patents

Description

Patented Sept. 16, 1952 UNITED Sm TRANSFER INK Joseph R. Ehrlich, New York, N. Y.

No Drawing. Application April 18,1949,

Serial No. 88,240

1 Claim. (Cl.10 6-23) My invention refers to transfer inks and products comprising such inks. In the following, the term transfer ink shall be used to denote inks as used primarily in connection with ofiice machines such as typewriting, billing, bookkeeping, addressing, duplicating machines, stamping devices etc., as distinct from commercial printing machines, and applied to carbon paper, typewriter ribbons, inking pads and sheets, including screens in duplicating machines. These inks are considered to be of the non-drying type, as distinct from commercial printing inks of the drying type. a

The term ink shall be used to'denote the coloring composition used on the aforesaid transfer media regardless whether it is present as a surface coating, as a body impregnant or saturant. It comprises coloring matter intermixed with or dissolved in a vehicle. Likewise, the word inked shall have the meaning of coated, impregnated or saturated withcoloring composition.

The term "carbon paper shall be applied to any paper of that kind, capable of rendering copies, even if its coating does not contain carbon black, as a pigment.

The term typewriter ribbon shall refer not only to the narrow ribbons used in the conventional typewriter machines, but also to any inked textile or paper used in any other machine serving the purpose of producing typed or duplicated texts or markings.

It is frequently desirable to distinguish certain words, phrases or numerals by a different color. For example, it is customary to make bookkeeping entries in black and red colors, signifying credit and debit items, as the case may be. This need has been recognized by supplying, for example, typewriters with the well-known black and red ribbons and a mechanism by which either black or red typing can be applied to the original. However, this device is unable to transmit thecolor distinction to the carbon copies which are always black or in any other uniform color; hence, the copies are not entirely identical with the original and fail to reproduce certain. important aspects thereof. The deficiency is so serious that special typewriters are made whichhave two sets of numerals, one in normal and the other in cursive script. By this means distinctions are transmitted to the copies but they are not as conspicuous as contrasting colors and it is impossible to duplicate all characters on a typewriter in thismanner. v, 1

There are also certain oifice. machines. such as billing machines, addressing machines, electric typewriters, typing machinesusing inking pads, stamping devices etc. which operate with the help of inked ribbons; sheets or pads; the mechanism of those machines does not permit the use of two colored inking devices, though, in many cases, the availability of more than one color would be most desirable. n

It is an object of my invention to provide a carbon paper which, when used in the'c'onventional way, permits the making of copies in more than one color. Another object is to provide typewriter ribbons, inked sheets or pads which, though inked in one uniform color, permit the making of typed or stamped texts or markings in more than one color. It is still another object to obtain these results'by' a simple treatment which can be execu'tedwithout special skill. As a further object, the color variability is to reside completely in the ink of the transfer medium so that its imprint on any kind of avail-able paper, fabric or other base may be made to change its color.

Conventional carbon paper ink is a mixture of oils, fats, waxes and/or resins serving as a vehicle for finely divided insoluble pigments and/or soluble dyestuffs. Record typewriter ribbon ink is similarly composed in principle, though with some changes regarding the composition and ratio of, the basic ingredients. Thus, a black carbon paper or a black typewriter ribbon usually contains carbon black and a black dyestuif such as, e. g. a, fat-soluble nigrosin base and/or other dyestuffs to neutralize eventual undertones and thus produce a pure, opaque black. The same principle is applied in carbon papers or ribbons of other colors, 1. e. pigments and dyes of the same basic color are used in combination. While it is possible to make a carbon paper or a typewriter ribbon with an ink containing a dyestuff dissolved in the vehicle and no pigment'or at least a relatively s'mallamountof pigment, it'is des-irable to fill the ink fwithja considerable amount of'pi-gment. Thisis especially true'for ribbons. Not only do transfer inks containing no pigment or not enough thereof fail to meet the requirements of permanence of the typed or stamped texts and markings-including erasability with chemical ink eradicators, but they also exhibit a tendency to bleeding. IA poorly filled" ink is also the reason for unclear, inaccurately contoured typed copies since it spatters easily under heavy impact of the metal types, thus making the contours of their imprint hazy. A suflicient amount of pigment gives the ink enough "body to hold the colored mass together and to prevent it from spattering under impact. While a carbon paper ink can derive at least part of its body from the relatively high percentage of high melting wax which makes up part of the ink composition, a typewriter ribbon ink has to rely for body almost entirely on its sufl'icient pigment contents. Liquid inks at room temperature for ribbons, inking sheets or. felt pads would definitely bleed and display an undesirable lack of opaqueness, unless they are heavily filled I with pigment. Y

According to my invention, I incorporate into the ink vehicle a pigment or filler having one basic color, with the exception of black, and

another pigment or colored filler having another I and yellow dyestuffs in such proportion that the combination of red hidden pigment and black dominating" pigment, with or Without black basic color, including black, and difierent mm the first; both pigments or fillers being insoluble in the vehicle; the second pigment being present in sufficient quantity either to produce, together with the first pigment, a substantially diiferent ink colo'rcrto' impose its own color by completely hiding,-'covering,and suppressing that of thefirst pigment. This can be helped and improved by also adding a small amount of dyestufi or a combination of dyestuffs of the same basic color as the second pigment, or a dyestufi modifying the shade of the second pigment, but different-from the color of the first pigment. In'the following,

the first pigment will be called the hidden pigment or filler and the second pigment will be called the dominant pigment or filler. 'The dominant pigment and the soluble dyestuffs so employed must be susceptible to the action of chemical'agents capable of either destroying their tinctorial power-or of changingtheir basic color, whereas the,hidden pigment employed must be inert towards the same chemical agents and its color must not be affected the'reb'yj In consequence, the chemical treatment of the typed or stamped text or copy 'makes the color of the hidden pigment appear, either as such or modi fled by the changed. color of the dominant pigment and/or dyestufi', causing the treated passage to assume a contrastingcolor.

1 It is possible to suppress the color of the.hidden pigment by'incorporating into the vehicle only soluble dyestuffs of contrasting color,-and no dominant pigment at alli But in this case the hidden pigment. will constitute the total of fillers in the ink, a'quantity which necessarily is limited, if the color or the "hidden pigment is notsupposed to show. On the'other hand, as all the 'tinctorial power in the unreacted ink has to be contributed in such a case by the solubleldyestuff or dyestuffs alone, in order to suppressthe tinctorial power of the hidden" pigment, an excessive amount of soluble dyestufi is required. Both, the limited amount of filler and the excess of dyestuff may lead to the undesirable conditions as described in the foregoing, in particulanbleeding, lack of opacity and spattering; or, if these conditions can be compromised or reconciled to a certain extent, it will be at the expense of the purity of the color of the ink. "The use of the dominant pigment makes it possible to produce an ink for carbon papentypewriter ribbons and similar applications which embodies the best per formance quality together with the additional feature of changeable color. Such products yield clear, clean colored, sharply contoured, steel type like imprints, writing or copies .which do not bleed and are thoroughly opaque 'and" permanent. l. f'

Depending on the type of'the dominant pig'- dye appearsblack. Properly formulated, this ink can be either app lied to carbon paper or a typewriterribb'on which resemble ordinary black carbon paper or black ribbon and yield black copies or black typed texts. However, black typed texts or copies so made can be turned into red immediately upon contact with a strong oxidizing agent. For example, if it isdesired-tomake certain words or numbers appear in red it merely is necessary to touch them with one of the commercial chemical ink eradicators, for example with an aqueous solution .of sodium hypochlorite followed by. diluted acid, or of potassium permanganate followed by oxalic acid, or of other oxidizingagents. Y i t A typewriter ribbon..one half of its width inked alon'gl its entire length, with an ordinary blue typewriter ink, and the other half of its width inked with a black-to-red color-convertible ink, as described above, will permit to .type'in three different colors: blue, b1ack,.and by contacting the black text withv an oxidizing agent, red.

The same black-to-red color convertible ink. applied to one half of the ribbon,.'an'd an ink with a pigment combination consisting of an inert green lake .toner with'a violet discharge pigment such as phosphor tungstated methylviolet plus a little methylviolet base dissolved in the vehicle will produce a black-purple ribbonwhich'will type either in blackor in purple; the black bein changeable into red and the purple-being changeable into green upon contact with strong oxidizing agents; thus it becomes possible to type in four different'colors, with one 'ribbon', in a regular typ ew riting machine.

, Ihe .dominant" pigments which I use are oi the discharge type. They maybe, for example, iron tannate, iron gallate, phosphor'tungstated basic dyes such as Victoria blue base, methylviolet basefmalachit'e'green.baseand others, or natural organic pigments such as carmine lake. all of them reacting with oxidizing agents. I can also use dyestufis which areprecipitated on aluminum'hydrates'iand are sensitive toward pH changes, such as m'ethylviolet, turning. light green and finally yellow. contact with diluted hydrochloricacid. I

'Dyestufis' of any. chemical composition and structure can be used, sublie'zct'to 'the,.requirements of solubility in the vehicleyand. susceptibility m ne chemical" agents.,employed to bring about the. desired color. conversion. in the copy. The effects of these various-agents" on the dyestuits is well'known to the art and theyrequire noexperimentation for the purpose of my invenion.

The hidden pigments used according to my invention may have any chemical composition. the, only limiting attributes being insolubility in the vehicle and their resistance'to the chemical agents employed. The pigments may be inorgani'c' substancessuch as Milori blue (a special .5 kindof Prussian blue used in printing inks), vermillion,'cadmium red, chrome green, chrome yellow, ferric oxides, tungsten colors, etc.,-for theymaybe color'lakes or toners such as,-e..g., lithol reds, Burma'red, India red which are calcium and'strontium salts respectively of-rhodamine,etc. '1

The conventional vehicles for the coloring 'm'atters in transfer inks are mixtures of oils/fats, waxes, resins and other materials which are'most- 1y water-insoluble and even water-repellent. Most of the chemical reactions useful to effect the color changes on which my invention is based proceed only'in the aqueous solution or at least require the'presence of water. For this reason and in order to apply my invention to best advantage, acting rapidlyand yielding even results particularly if the copy is rather heavy, I employ vehicles which contain or which consist entirely of hydrophilic substances. The latter are not necessarily water-soluble but capable of absorbing and retaining a certain amount of water if in contact therewith andthus assure rapid, complete and uniform action by, the chemical agents used to produce the color changes.

I prefer hydrophilic substances of rather low hygroscopicity. If the hygroscopicity of glycerin is compared with that of other substances by exposing them together under the same conditions to humid air,- and weighing their increase "of weight, and the hygroscopicity of glycerine is taken at 100. I prefer substances with a hygroscopicity of less than 30.

Another condition is that the hydrophilic substances which I use in the vehicle of said transfer inks are suficiently compatible to be mixed with certain waxes, or fats, or oils in the desired ratios. Thus, I can use certain polyalkylene glycols of a molecular weight of about 500 and more. Certain polypropylene glycols of mol.-weight 750 to 1300, for example, are liquid hydrophilic substances of low hygroscopicity which are compatible with carnauba wax, beeswax etc. Certain waxlike polyethylene glycols of molecular weight of more than 500 represent solid substances of that class that can be used for my purpose.

Numerous combinations of substances of fat, oil, wax and resin character can be used to produce the vehicle which must possess the physical properties suitable for application as a transfer and duplicating ink which must be serviceable by all standards demanded of the specific article (carbon paper, typewriter ribbon, inking pad, etc.) in its various uses. However, for the best embodiment of my invention it is advantageous that the vehicle have the additional quality, not required in the conventional transfer and duplicating inks of admitting aqueous reagents. If the vehicle itself is not sufliciently water-absorptive, adequate amounts of hydrophilic ingredients must be added to it.

Among other ingredients of hydrophilic character may be mentioned esters of polyhydric alcohols and ether-alcohols, such as the series of ether glycols known in the trade as dito dodecaethylene glycols, with long-chain fatty acids such as lauric, stearic, myristic, oleic, linoleic or ricinoleic acid; ammonium, amine salts of the same acids; alkyl amines containing between 8 and 22 carbon atoms and their salts.

In some substances useful as vehicle ingredients, such as diethylene glycol mono stearate, diethylene glycol monoor dioleate etc., the hy- 2 parts of Burma red (insoluble red toner) The black ink thus obtained is coated on a paper by one of the usual methods. Upon touching the black carbon copy with an aqueous solution of sodium hypochloritaabout 2 strength, followed by touching with dilute hydrochloric'acid, and subsequent blotting, the color or thecopy changes immediately from black to a'permanent. red.

EXAMPLE 2; g g Transfer ink for carbon paper 24: parts of morpholine stearate 25 parts of carnauba wax 17 parts of diethylene glycolfoleate 20 parts of iron tannate I 8 parts of India red (insoluble red toner) 2.7 parts of malachite green base 1.95 parts of Victoria blue base .3 part of methylviolet base 1.05 parts of oil yellow (oil-soluble 'dyestuii) 1 are intimately mixed, heatedand milled as in Example 1. The neutral black copy changes rapidly to red upon treatment with a 5% potassium permanganate solution followed by an aqueous 10% oxalic acid solution, or upon treatment with sodium hypochlorite solution as in Example 1. H i I EXAMPLE 3 5 Transfer ink for typewriter ribbon or inking pad 50 pints of diethylene glycol oleate or turkey red parts of discharge black (iron tannate) 10 parts of Burma red (insoluble red toner) 5 parts of Oil Black GMBA 1831 (oil-soluble antrachinone dyestuif) are intimately mixed and milled. A fabric of cotton, silk, nylon or other material in sheet or ribbon form, or apiece of felt is inked by one of the usual methods. The neutral black typed text or markings turn immediately into brilliant red upon contact with sodium hypochlorite solution, followed by diluted acid as specified in Example 1.

EXAMPLE 4 Transfer inks for four color typewriter ribbon 5 parts of ethylcellulose (alkyl contents 47%,

viscosity 200 cps.)

50 parts of diethylene glycol oleate are heated and stirred together until the ethylceliulose is dissolved; then 5 parts of Oil Black GMBA 1831 (oil-soluble dyestuff) are added and dissolved;

10 parts of Burma red (red lake toner) 30 parts of iron tannate (discharge pigment) are added and all together thoroughly milled.

With this composition one half of the width of a ribbon is inked by one of the usual methods.

The other half of the ribbon is inked with the I 7 following ink compositim,:ma-dexinganzanaloequs way i 45 parts of polypropylenel g'lycol mol. w. 1250 10 parts of carnauba wax parts of Victoria blue base parts of green lake toner 30 parts of phosphorltungstatedNictoriaiblue (dischargepigment) One part of the ribboniltypes,,blaekwhieh .can be turned into red and the fother pertpf the ribbon types blue that c'an'be turnedgintdgreen, both upon contact with sodium. hypochloritesolution as used in'Example'l.

.fiuplieatinafiztk 151 )arts of diethylene glycolrstearate 10 parts of- India' redfled' lake toner) parts of methylviolet aluminum Lhydroxide precipitate 47 parts of diethylene glycokoleete 8 parts of methylviolet base are heated, intimately. mixed And thoroughly milled. Purple copies made 'Withthis'inkturn red upon contact with dilutedhydrochloridacid of about /4 N strength.

.16 "Min -W W 8 parts of purple lake-.toner..(inwlubl.e) 35 partsof ,carmine515 5. 5 parts oirhodaminebese 52 parts' or polypropyleneii lyoolmol. w.ri 0 The arkingsturn from'red tqpu ple umnce tactwith sodium hypochlorite:solution, ;u s ed iii-Example 1. 1

-Allquantities indicated in the above-"examples are in parts by weight.

It will be understoqd that,without departure rmm-;.the;:sp1r1t ofithe :inventionzorzthe. scone .10! m aim. vnriqu modflicationsmav: bemedeln the specificexpedientsadescribed- The. la termt only; i1lustztabive.. and notofleredgin a; restrictive sense, it bein'gxdesired;on1y:euch;;1imitationsshall be placed thereongas may berequired-thyv the state of the prior art.

Jiztransfer ink comprising aflisnersed waterinsoluble imntannatemi ment; present; i .quantity .sufiicient :to make themarkingpolorof, said ink'rsubstantially: black,nndwatrieasteone .waterinsoluble :red ;:pigme. .1tvrcs.istant-,to ,an equeous oxidizinggagtentrcomprisin 1013 S lected from the nonpzotihypochloritezandperxnanaanete ions.

. BE E ENGES Q ED The follow-ing :references 4 are of:- record in the fiIeQof this patent:

U rrED;sTATES"PAT NTs O'II IER. REEERENGES Mitchelet a1: Inks; Composition and Manufacture, 1916} pp. 233 and 234.

Leh-ner Ink Manufacture, 1926, p. -44.