US3681186A

US3681186A - Multicolored unitary self-supported polymer matrix transfer medium

Info

Publication number: US3681186A
Application number: US97744A
Authority: US
Inventors: Hugh T Findlay; Jerry F Stone
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1970-12-14
Filing date: 1970-12-14
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01
Also published as: GB1365136A; DE2161601A1; FR2118464A5; JPS532084B1

Abstract

A MULTICOLOR TRANSFER MEDIUM IS PROVIDED BY A PROCESS WHICH COMPRISES MAKING A FIRST MATRIX MATERIAL BY MIXING A FLUID TRANSFER INK OF A FIRST COLOR WITH A SOLUTION OF A FILM FORMING POLYMER IN A SOLVENT FOR THE POLYMER, COATING THE RESULTING DISPERSION ON A FIRST SUBSTRATE AND EVAPORATING THE SOLVENT TO FORM THE MATRIX MATERIAL OF A FIRST COLOR. A MATRIX MATERIAL OF A SECOND COLOR IS FORMED IN AN IDENTICAL MANNER UTILIZING A FLUID TRANSFER INK OF A SECOND COLOR. THE TWO SUBSTRATES SUPPORTING THE MATRIX MATERIALS ARE

THEN PLACED IN ADJACENT EDGE ALIGNED RELATIONSHIP TO ONE ANOTHER ON A THIRD SUBSTRATE WHICH HAS BEEN COATED WITH A FUGITIVE ADHESIVE AND A POLYMER IS THEREAFTER BACK COATED OVER THE TWO MATRIX MATERIALS TO SEAL THEM TOGETHER. THE RESULTING UNITARY MULTICOLORED TRANSFER MEDIUM IS THEN STRIPPED FROM THE SUBSTRATES AND SLIT, IF REQUIRED, TO A DESIRED WIDTH.

Description

Aug. 1, 1972 H. T. FINDLAY ETAL 3,

MULTICOLORED UNITARY SELF'SUPPORTED POLYMER MATRIX TRANSFER MEDIUM Filed Dec. 14, 1970 gig-12 1:: O0 08 a, 0

INVENTORS HUGH T. FINDLAY JERRY F. STONE By M w SUBSTRATE A] Town;

' US. or. 161-166 ABSTRACT OF THE DISCLOSURE A multicolor transfer medium is provided by a process which comprises making a first matrix material by mixing a fluid transfer ink of a first color with a solution of a film forming polymer in a solvent for the polymer, coating the resulting dispersion on a first substrate and evaporating the solvent to form the matrix material of a first color. A matrix material of a second color is formed in an identical manner utilizing a fluid transfer ink of a second color. The two substrates supporting the matrix materials are then placed in adjacent edge aligned relationship to one another on a third substrate which has been coated with a fugitive adhesive and a polymer is thereafter back coated over the two matrix materials to seal them together. The resulting unitary multicolored transfer medium is then stripped from the substrates and slit, if required, to a desired width.

BRIEF BACKGROUND OF INVENTION 1 Field This invention relates broadly to a novel transfer medium useful as carbon paper, typewriter ribbon or the like. More specifically the present invention is directed to reusable multicolored plastic transfer elements and to methods for making such transfer elements.

(2) Description of the prior art Multicolored transfer elements now in common usage may be generally classified in the following two broad categories: Ink impregnated woven fabrics and single use carbon paper and carbon film materials. The multicolored woven fabric is generally produced by passing the fabric over a split inking roller having the various colored inks located thereon in a manner to transfer the ink from the roller to the' fabric. Great care must be taken to insure proper alignment of the fabric with the roller to insure ribbon uniformity. Further, great care must be taken in the selection of the inks utilized to insure that they have proper thixotropy and bleed characteristics. Also, due to the caliper of the fabric, the impregnated woven fabric ribbons are characterized by lack of conformity of the fabric to the type face under impact and this results in a low quality transfer. This low quality transfer is further aggravated by the lack of dyestuif that is characteristic of fabric two color ribbon inks (the lack of dyestuif insuring ink separation).

Conventional single use carbon paper and film ribbons have relatively high quality transfer characteristcs, but, due to their extremely thin caliper and structure, must be disposed of after single use. Various methods have been devised for making multicolored film ribbons such as to thermally couple or adhesively couple such ribbons to a substrate which remains as an integral part of the ribbon. While such a ribbon is of thicker caliper than a single United States Patent color ribbon, it is still not reusable because of the total transfer characteristic of such ribbons. Accordingly, when such a medium is utilized for a typewriter ribbon, the ribbon is passed through the machine one time 'with the result that only one portion of the medium (that portion containing the selected color) is utilized.

A third type of transfer medium has been suggested in the prior art: reusable porous polymer films. An example of such a medium is fully described in US. Pat. 3,413,- 184 entitled Transfer Medium and Method for Making Same. Such a medium comprises a solid, continuous porous matrix containing globules of a liquid or jelled ink within the pores. A wide variety of inks may be utilized in conjunction with such a medium, the only constraint on the ink being that it is relatively insoluble in low concentration of the solvent in which the polymer and ink are dispersed during the manufacturing process. When a transfer medium is constructed in accordance with the afore referenced Pat. 3,413,184, the resulting material is of a thin caliper, but yet the spongy like construction of the thin caliper material allows it to be used over and over. Since the ink and resin are dispersed in a liquid-form during the manufacturing process, casting of more than one color ink and matrix simultaneously results in intermixing and contamination of one colored matrix with another. Further, it is not possible to manufacture a multicolor polymer film utilizing conventional multicolor fabric ribbon inking or those multicolor carbon film material techniques which require thermal bonding. Although a multicolor medium could be produced by coupling two matrix materials to a substrate layer in aligned relation utilizing the adhesive approach heretofore taught in the formation of carbon films of multiple colors, the resultant product would be of thicker caliper and great care would have to be taken in selecting a proper substrate medium and adhesive which would co-act with the thus coupled transfer medium in a manner to produce legible and consistant graphic symbols when utilized in an environment such as a typewriter. That is, the selection of the adhesive and substrate vary the transfer characteristics of the medium and unless great care is utilized in selecting these components, a ribbon having the attributes of the polymer matrix would not result.

SUMMARY In order to overcome the above problems and shortcomings of the prior art and to provide a multicolored unitary spongeous transfer medium, the transfer medium of the present invention is formed during three separate operations. During the first operation, a matrix material of a first color having varying porosity throughout horizontal zones thereof is formed on a first temporary substrate in a manner similar to that described in US. Pat. 3,413,184. Thereafter, a second matrix material of a second color is formed on a second substrate in an analogous manner. The two substrates supporting the matrix materials are then placed in edge aligned relation on a sup port substrate containing a liquid adhesive. The liquid adhesive facilitates initial lateral movement of the material carrying substrates in order to effect the precise alignment of the substrates and also couples them to the support substrate. Thereafter, a back coating of the polymer is applied over the two matrix materials and the exposed portions of the substrates. The back coating is continuous with the polymer phase of the matrix materials and forms a barrier between the discrete colored strips. The discrete separation between the colored strips and the barrier prevent bleeding of inks of one color strip to the other. The liquid adhesive prevents excessive penetration of the polymer to the substrate. The transfer medium is then stripped from the substrates and the medium may be slit to desired widths.

The invention will be better understood in the light of the following description and claims and the accompanying drawings which illustrate, by way of example, a preferred mode for carrying out the present invention.

In the drawings:

FIG. 1 is a schematic side elevational view of a system or apparatus for carrying out the process of the present invention.

FIGS. 2a, 2b, 2c, 2d, and 2e are edge views of the transfer medium as it is manufactured.

As described in the aforereferenced Pat. 3,413,184, the continuous porous matrix of the transfer medium can be made of a suitable synthetic polymer which includes the following: polyamide resins such as nylon, polyurethane, polycarbonates, polyethylene, polypropylene, polyvinyl acetate, polyvinyl chloride, vinyl chloride, acrylonitrile butadiene, cellulose acetate butyrate and cellulose acetate. Other synthetic resins or mixtures of synthetic and natural resins capable of forming thin, self supporting porous matrices may be substituted for the foregoing without departing from the scope of the invention. The exact composition of the inks incorporated in the pores of the polymer matrix is not critical and may be in the form of either a fluid ink or a jellied ink. One requirement of the ink is that it not be soluble in the polymer matrix. An additional requirement is that it is non volatile at temperatures used to form the matrix. Thus, most oil base dye soluble inks, Water base dye soluble inks and pigmented thixotropic inks with and without dyes, could be used. In accordance with the disclosure of the aforementioned patent, the polymer is dissolved in a volatile solvent and the ink is distributed in the polymer solution. This solution is then coated on a temporary heat stable substrate such as a paper web or an endless belt of Mylar. The solvent is then evaporated, and during this action, a relatively high concentration of plastic is obtained at the upper surface and a higher concentration of ink is obtained at the lower surface adjacent to the temporary substrate.

According to the present invention, a plurality of polymer matrix transfer materials each of dilfering colors are formed as described above on a like plurality of temporary substrates. The substrate supported matrix materials are then slit to required widths without peeling them from their substrates. A temporary heat stable support substrate is then prepared by coating it with a film of liquid adhesive. The adhesive may be a fugitive adhesive such as a solution of water and wetting agent (e.g. polyethylene glycol) or isopropanol and glycerin or a permanent adhesive such as ethylene acetate copolymer or acrylonitrile butadiene or a hot melt adhesive (e.g. wax blends). A plurality of slit matrix material supporting substrates are then placed in edge aligned relationship on the adhesive layer of the support substrate. The film of adhesive facilitates initial alignment of the matrix material supporting substrates with respect to one another permitting lateral movement of these substrates over the support substrate. When a fugitive adhesive is used it is partially evaporated and absorbed causing the matrix supporting substrates to become temporarily but firmly adhered to the support substrate. Conventional adhesives and hot melt adhesives solidify to permanently join the substrates. With the substrates thus coupled, movement of the substrates with respect to one another is prevented during subsequent handling and coating operations.

A back coating of a polymer material preferably of the same polymer material utilized to form the matrix materials is dissolved in a solvent and applied over the matrix materials and the exposed portions of the substrates. The applied polymer penetrates between the matrix materials to form. a minute barrier layer between the substrate supported matrix materials. The adhesive located on the support substrate prevents excessive penetration of the support substrate by the polymer material. The solvent is evaporated leaving an integral solvent bonded polymer film on the top surface of and bet-ween the matrix materials. The matrix materials and the polymer film bonded thereto are then peeled from the temporary substrates resulting in a unitary multicolor transfer medium. The edges of the transfer medium can thereafter be slit to obtain a medium of a desired Width and to remove excess polymer material.

It has further been found that when a polymer receptive support substrate is utilized, and when the matrix material supporting substrates have clear edge definition, the back coated matrix materials may be stripped from the substrates leaving the excess back coated polymer material with the substrates resulting in a unitary transfer medium having clearly defined straight edges which require no further slitting operation.

The present invention will be better understood in light of the following detailed examples:

EXAMPLE I A three color transfer element in accordance with the present invention is prepared in the following manner:

(1) A black color ink and filler dispersed in a nylonethyl alcohol solution is prepared by following steps (1) through (4) of Example I of the afore referenced US. Pat. 3,418,184. This mixture is coated onto a temporary 1 mil thick Mylar substrate and dried in the exact manner described in the afore referenced patent resulting in a one mil thick black matrix material film layer on the Mylar substrate. The ink distribution within the matrix is non uniform as described in the patent. The substrate and film are then wound onto a take up reel.

(2) A red color ink and filler dispersed in a nylonsolvent solution is prepared in the following manner:

(a) A solvent mixture of 5 parts isopropyl alcohol, (isopropanol) 4 /2 parts ethyl alcohol (ethanol) and /2 part water is prepared by stirring at room temperature.

(b) One part by weight of nylon is dissolved in a suflicient quantity of sol-vent mixture prepared in step (2a) to produce a solution containing 12% nylon and 88% solvent. The solution is obtained by mixing the nylon and solvent mixture in a Cowles dissolver at a temperature of 140 F. Stirring expedites the solution.

(0) The following ink ingredients are weighed into a steel ball mill and are milled for approximately 8 hours:

Ingredient: Percent by weight Modified polyvinyl pyrrolidone polymer (Ganex V 216 produced by General Aniline and Film Corp.) 35

Low viscosity oil (Kronisol R-9 produced by Ohio Apex Corp.) 30

Red pigment (Irgazin Red 2BLT produced by Geigy Chemical Corp.) 35

Total (d) Three parts by weight of diatomaceous earth is mixed with the nylon-solvent solution prepared in step 2b until the admixture is homogeneous.

(e) Five parts by weight of the ink prepared in step 20 is then slowly added to the mixture of filler and the nylonsolvent solution prepared in step 2d under high speed agitation in a Cowles dissolver, until complete distribution of the ink and filler in the nylon solution is obtained.

The mixture obtained in step 22 is coated onto a temporary 1 mil thick Mylar substrate and dried in the exact manner described in the afore-referenced patent resulting in a one mil thick red matrix material film layer on the Mylar substrate. The substrate and film are wound onto a take up reel.

(3) A blue-black color ink and filler dispersed in a nylon-solvent solution is prepared as in step 2 except the following ink ingredients are utilized in place of those specified in step 20.

The mixture is coated as in steps 1 and 2 resulting in a one mil thick blue-black matrix material film layer on a 1 mil Mylar substrate. The substrate and film are wound onto a take up reel.

(4) All substrate supported matrix material prepared in roll form in steps 1-3 is slit to required ribbon width and rewound in roll form. The material prepared by step 1 is slit to a width of 0.4 and the materials prepared by steps 2 and 3 are slit to a width of 0.021".

(S) A solution of 95% by weight water and 5% by weight polyethyelne glycol 400 monolaurate (Aldosperse L9 produced by Glyco Chemicals Inc.) is prepared by stirring at room temperature.

(6) Three parts by weight of nylon is dissolved separately in a three-to-one mixture of ethyl alcohol and water by stirring in a Cowles dissolver at 140 F. to produce a solution of 5% nylon and 95% ethyl alcohol and water.

Referring now to FIG. 1 of the drawings, all cut matrix material in roll form (Step 4) is mounted on shafts 11 and 13. The

matrix materials

15, 17 are staggered with respect to each other on the two shafts and placed in the required order of the finished transfer element, the wider material being located intermediate the narrow material. A 2 mil Mylar substrate 19 is mounted on supply shaft 21. The water-polyethylene glycol solution (Step 5) is placed in tank 23 and wiped onto the 2 mil Mylar substrate to form a 0.1 mil film on the substrate. The substrate is then passed over the guide roller 24 with the film side up. The matrix materials are taken from their respective supply rolls and are edge aligned as they pass through the spring mounted concave guide pulley 25. The Mylar substrate side of the matrix materials is then located over the 2 mil Mylar substrate at the guide roller 24. The water-polyethylene glycol film initially facilitates lateral movement of the matrix supporting Mylar substrates to effect perfect alignment. The materials are then passed through a Gardner applicator 27 containing the nylonethyl alcohol mixture (step 6) which deposits 0.5 to 1.0 mil dry nylon on the back surface of the matrix materials. The back-coated matrix materials are then passed through a drying oven where an average temperature of 180 F. is maintained to disperse the solvent from the backcoated nylon and form an integral solvent bonded nylon film on the top surface of the nylon matrix materials. The unitary back coated matrix materials are then stripped from the one mil thick support substrates and the two mil support substrate which is attached to the one mil substrates and are wound on reel 31. The one mil substrates are separated from the two mil substrate (the fugitive adhesive bond is broken) and wound on reel 33. The two mil substrate is wound on reel 35. The transfer element on reel '31 may thereafter be slit to appropriate width, it being understood that a multiplicity of three colored transfer elements are formed in side by side relationship on a single 2 mil thick Mylar substrate. The finally slit transfer elements may then be wound onto small spools to obtain a three color typewriter ribbon.

6 EXAMPLE 11 A three color transfer element in accordance with the present invention is prepared in the following manner:

(1) Black, red, and blue matrix materials are prepared on one mil thick Mylar substrates in accordance with the methods described in steps 1-4 of Example I.

(2) A solution of 98% by weight isopropyl alcohol and 2% by weight glycerol is prepared by stirring at room temperature.

(3) A nylon back coating is prepared according to step 6 of Example I.

(4) The solution of step 2 is placed in the tank 23 of FIG. 1 and a 1.2 mil thick roll of highly calendered, low porosity glassine paper substrate material is mounted on the supply shaft 21. The glassine paper is wetted by the isopropyl alcohol-glycerol solution which conditions the substrate to make it receptive to nylon.

(5) The substrates of the matrix materials are applied over the film side of the glassine paper, the nylon backcoating is then applied and the backcoated transfer element is dried as described in Example I.

(6) The transfer element is then stripped from the substrates and wound, it being unnecessary to thereafter slit the transfer element.

FIG. 2 illustrates an enlarged, schematic edge view of the transfer element prepared according to Example II. FIG. 2a illustrates the red matrix material 51 located on its support substrate 53 the black matrix material 55 located on its support substrate 57 and the blue matrix material 59 located on its support substrate 61 after each substrate has been prepared according to step 1. FIG. 2b illustrates the glassine paper substrate 63 after its upper surface has been coated with the isopropyl alcohol-glycerol film 65. FIG. 20 illustrates the

matrix materials

51, 55 and 59 and their associated

substrates

53, 57 and 61 as they rest on the film coated glassine paper substrate 63. FIG. 2d illustrates the materials of FIG. 20 after a nylon backcoating 67 has been applied and dried. FIG. 2e illustrates the transfer element and the substrates after they have been stripped. The excess nylon backcoating 69 remains with the substrate 63 which is more receptive to the nylon than the edges of the

nylon substrates

53 and 61, the attractive force of the nylon to the substrate causing the nylon to break apart from the nylon coated transfer element along an edge thereof.

EXAMPLE III A transfer element was prepared in accordance with the method described in Example II utilizing a 2 mil thick carbonizing tissue substrate wetted with a 0.1 mil thick film of the isopropanol-glycerin solution prepared according to step 2 of Example 11.

EXAMPLE IV A transfer element was prepared in accordance with the method described in Example I utilizing the following water soluble ink formulation in lieu of the oil based formulation specified in the same percent by weight amount:

Ingredient: Percent by weight Polyethylene glycol (Carbowax 200 produced by Union Carbide Corp.) Water soluble Nigrosine (Nigrosine W.S.B. 40

produced by American Cyanamid Corp.) 20

IAS already noted above, various materials including those described in Examples III, IV, and V of 1.1.8. Pat. 3,413,184 may be substituted for the polymer, filler and inks described in the above examples without departing from the spirit of the present invention.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A process for making a multicolor unitary spongeous transfer medium comprising:

coating on a first temporary substrate a mixture comprising a volatile dispersant, a resin and ink, said ink being incompatible with the resin and having a first color;

coating on a second temporary substrate a mixture comprising a volatile dispersant, a resin, and ink, said ink being incompatible with the resin and having a second color;

expelling said dispersants from said mixtures;

coating a third substrate with an adhesive layer;

aligning the first and second substrates on the adhesive layer in edge aligned parallel relation to one another; coating a resin and resin solvent solution over the resinin-k mixtures and exposed substrates;

expelling said resin solvent;

stripping the transfer medium from the substrates.

2. The process for making a multicolor unitary spongeous transfer medium set forth in claim 1 further comprising the step of slitting the transfer medium into the form of a ribbon having the dimension desired for use as a typewriter ribbon.

3. The process for making a multicolor unitary spongeous transfer medium set forth in claim 1 wherein said third substrate is coated with a fugitive adhesive layer comprising a thin film of volatile fluid.

4. The process for making a multicolor unitary spongeous transfer medium set forth in claim 3 wherein said fugitive adhesive conditions the surface of the third substrate to be receptive to and bond with the resin coating.

5. A multicolor transfer element comprising a polymer film having a plurality of pores, a horizontal zone near one surface of the film having significant relatively high density of said pores, a second horizontal zone near the opposite surface having a significant relatively low density of said pores, globules of fluid transfer ink of a first color in the pores located within a first vertical zone and globules of fluid transfer ink of a second color in the pores in a second vertical zone laterally adjacent to said first vertical zone.

6. The multicolor transfer element set forth in claim 5 further comprising a thin zone of polymer film of relatively low density of pores located intermediate said first and said second vertical zones.

References Cited UNITED STATES PATENTS 3,101,668 8/1963 Leeds 101401.l

WILLIAM A. POWELL, Primary Examiner US. Cl. X.R.