DE1931013A1 - Squeeze type pressure sensitive carbon paper and method for making the same - Google Patents

Description

COIUMBIA RIBBON AND CARBON
MANUFACTURING CO., INC.

527 Herbhill Road

Glen Cove. N.Y. /V.St.A. Our sign; 0 2683

Peek-out type pressure sensitive carbon paper and method for making the same

The invention "relates to the field of so-called "Squeeze" carbon papers and tapes that look like color transfer has a microporous, non-transferable resin structure, in the pores of which one under pressure exiting, consisting of an oily ink carrier and an image-forming substance is contained. Such carbon papers and ribbons are, inter alia, in German patents 1,178,091 and 1,169,968 as well as U.S. Patents 2,820,717, 3,037,879, and 3 described. '

Such known carbon papers and the like have emerged especially because of their repeated usability proved to be extremely useful. The resin binder Dr, Ha / Ktl

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mm ^ mm. .

is not transferable and its porosity allows it the flowable paint to wander and spots from which Color has been transferred to replenish. However, although the easy flowability gives this advantage, it has the disadvantage that a certain amount of color exits on the copy sheet placed when the Sheets are fed into a typewriter or similar office machine that has rollers between which the arches are pressed together.

This undesired leakage of paint can be avoided or at least be reduced if the color layer is made from harder, less pressure transferable resins or resin mixtures or when using semi-solid paint carriers. However, this increases the pressure sensitivity the color layer is degraded, so that the typed copies do not have the desired color density especially if carbon paper is used to make a large number of copies during a writing process are interposed.

The undesired color leakage can also be avoided or can be reduced by making a thin contiguous Applying resin coating to the ink-releasing layer, which under the action of an imaging pressure Allow color to pass through from the color-releasing layer. However, if such a coating has no openings, he very strongly inhibits the passage of color, so that the first from a certain point of such a carbon paper produced copy is very faintly toned. The following copies then have an uneven tint, and due to earlier tearing of the coating in some places and not in others.

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To overcome these problems, the resin coating has heretofore been either printed or screened applied as a resin solution incompatible with the ink carrier of the ink-releasing layer, so that the resin from the open, paint-filled pores on the surface the ink-releasing layer is kept away, but a contiguous one over the other places Forms coating. Although these methods prevent unwanted paint leakage to a certain extent, in any case, they are only a compromise, since they are not uninterrupted or omnipresent Resistance - against the leakage of paint from "the paint layer bid under pressure. Such coatings only hold the dye-releasing layer off hands or off the copy sheet, and the degree to which this occurs will be dictated by the required Limited thinness of the coating, which must not exceed a thickness of about 0.0025 mm (0.0001 inch) ^ so that the even typing power of the carbon paper is not impaired. However, such coatings leave the formation of roll marks on a. Copy sheet below that exerted by the typewriter rollers while the sheets are being inserted into a typewriter Pressure to, especially with repeated use or when thicker coatings to avoid this disadvantage are applied, uneven or unevenly toned image areas are obtained as a result of the sealing of the color-releasing Pores in some places of the color-releasing: Layer. Sieve-like or net-like coatings also have the important disadvantage that they change the color through the Openings in the screen or mesh give off what image areas with a clearly visible cross-hatched pattern. Such image areas are tinted lighter than

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is desired and actually resemble printed raster image locations.

. The main object of the invention is therefore to create

improved squeeze type carbon papers and the like, which have a clean grip and leave no roller marks on the copy sheet, but almost completely maintain their pressure sensitivity, so that one evenly tinted and extremely intense image areas scored even the first time you use it. More | Objects and advantages of the invention will be apparent to those skilled in the art apparent from the following description in conjunction with the drawing.

In the drawing show:

Fig. 1 is a schematic representation of the

Method for applying the inventive Coatings and

Fig. 2 is a schematic, enlarged cross-sectional view of a carbon paper obtained according to the invention.

The objects of the invention are achieved in achieving the specified advantages fulfilled by the fact that one is on the color-releasing surface of a liquid, under Pressure-leaking paint containing the squeeze-out resin layer prints a thin coating composition consisting of a thinned solution of 1 part by weight of a synthetic thermoplastic resin and up to about 0.8 part by weight of one or more incompatible with the resin, However, liquid oily substances compatible with the liquid color of the underlying resin layer in a volatile solvent. The solvent

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forms at least a partial solvent for the resin binder of the ink-releasing layer and leaves it behind when evaporating, an evenly thin, porous resin coating that contains this oily substance in its pores and attacks itself completely clean and does not come off under the action of an imaging pressure the color-releasing layer peeled off.

The oily material is soluble or dispersible in the solvents used to apply the coating and is therefore evenly distributed in the coating during application. When the solvent evaporates the oily substance separates from the resin in the form of the smallest, evenly in the dry coating distributed droplets. Although the coating is extremely thin, less than about 0.0025 mm the dispersed droplets form a barrier against the leakage of the ink on the hands or on a copy sheet, unless imaging pressure is used. Under the action of such pressure the paint can pass freely through the pores of the coating and the small ones contained in the coating Amount of the oily matter mixes with the paint during this passage; it was found that this has no noticeable effect on the uniformity of the hue of the image areas produced.

The chemical properties of the. according to the invention Liquid oils used in coating compounds are very important * Only oils that come with the resin are suitable incompatible with the coating and with at least one of the oily constituents of the dye carrier, the dye-releasing agent Layer are compatible. This latter compatibility

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allows the coating composition to have an affinity for the surface of the ink-releasing layer, so that it sticks to the printed areas and does not lift or be repelled. It is this for the invention in view of the extreme thinness of the applied layer, it is extremely important. The oily one Liquid can be or act as a wetting agent by giving the coating composition an affinity for the surface of the color-releasing layer ^ and thereby enables the coating to be thin Layer in the printed areas on the color-releasing Layer remains.

According to a preferred embodiment, the A customary wetting agent is added to the coating composition. The wetting agent supports the reliable application of coatings with the required uniform thinness. The wetting agent is preferably an oily one Liquid that is incompatible with the resin of the coating and with the ink carrier of the ink-releasing layer is compatible, so that a single substance is used in the cover to fulfill both functions "Can. The wetting agent sets the surface tension the coating mass down and results in a composition that is more evenly applied to the color-releasing layer Formation of a very thin coating with extremely uniform thickness can be spread. The wetting agent can be any liquid or solid that is present in the application of the coating volatile solvent used is soluble or dispersible.

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That for applying the coatings according to the invention The solvent used is also very important. Sin such a solvent must be at least a partial solvent for the resin binder of the dye-releasing agent Layer, however, has to be a good solvent for the ink carrier of this layer in the case of a rule Form room temperature working temperature. Most aromatic solvents, for example Toluene, xylene and the like, dissolve this color carrier too much, As a result, the color contaminates the coating composition and so the aim of the invention Purpose interferes. Therefore, only those volatile solvents are suitable which reduce the resin binder of the color-releasing Layer under ideal solution conditions, e.g. under the additional effect of heat and stirring solve well. Of course, the resin of the color layer does not dissolve too much during the application of the Coating, as this coating is applied at around room temperature * and the solvent evaporates almost immediately. However, the ability to dissolve has proven to be critical for the application of uniformly thin coatings proved the one. To resist transfer "under the action of imaging pressure. The Preferred solvents are the usual aliphatic liquids which are volatile at room temperature, incl. the ketones such as acetone and methyl ethyl ketone, the alcohols such as ethanol and the * esters such as ethyl acetate. Water is also a suitable solvent in systems containing water-soluble or water-swellable resins and Contain oils dispersible in water.

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Apparently the solvent wets and softens those present on the surface of the ink-releasing layer Resin binder, so that the coating is bonded to the surface of the paint layer by the solvent. That Solvent possesses a strong. Affinity for the resin of the color layer and thus acts roughly as a wetting agent, although it does not stay on the surface long enough to cause the resin to dissolve too much) works. This network effect also enables the thin cover to lie on the printed areas, without it being repelled by the paint layer, so that when the solvent evaporates, a uniformly thin layer forms. Although some solvents can dissolve oily liquids under ideal solution conditions, it has been found that they do not contain contaminating amounts of these substances at room temperatures can dissolve during the short residence time permitted by the method according to the invention «;

The preferred coating compositions according to the invention are composed of solutions containing 80 to 95 wt. $ $%. "Volatile solvent, 5 .to 10 wt. Synthetic thermoplastic resin binder, 1 to 5 wt. Of the oily liquid substance and 0.1 to 1 weight .. fo wetting agents Expressed on a dry weight basis, there are the preferred coatings of about 55 to 80 wt # resin, about 20 to about 45% by weight oily materials and from about 0.01 to 5 wt $ wetting agents may These proportions;...., depending on the the desired image strength can be varied.

The coating is applied to the surface of the paint layer. ■ prints and is leveled so that the wet film

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a thickness of about 0.00005 "when using a smooth rod, to about 0.0005" when using of a coiled wire rod. It is the thickness of the liquid coating that is mainly consists of the volatile solvent. The dry coating has an approximate thickness on the order of 5 to 20 # the thickness of the wet layer as the wet layer only contains 5 to 20 $ of solids. The preferred one Dry thickness is 0.05 to 0.5 points. One point is equal to 0.0001 inches. Expressed on a weight basis the coating mass is applied at a rate of from about 0.05 kg up to about 0.23 kg per ream and preferably applied at a rate of approximately 0.077 kg per ream. A ream is 500 sheets with dimensions

2 of 55.9 x 86.4 cm or approximately 242 m. After evaporation of the solvent, the dried coating weighs between about 0.0045 kg to about 0.023 kg / ream.

The coating according to the invention can be applied to the one shown in FIG the manner shown in the drawing are applied. The web of carbon paper 10 is transferred from the conveyor roller 11 Deflection rollers 12 brought up to the pressure roller 13, which continuously from the application roller 14, which is in the Coating compound containing trough 15 is immersed, receives transfer compound. The coating is on the underside of the The web is applied to the ink-releasing squeeze layer and is leveled by means of the rod 16. The wet The web then runs under the pulley 17 and over heating lamps 18, which cause an evaporation of the volatile Solvent and cause the solidification of the thin resin structure '. This is preferably done in a drying tunnel. Then the track runs under a second deflection

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roll 17 through onto take-up roll 19.

The structure of the finished carbon paper is as it was before said above, not entirely certain, but it seems to be that shown in Figure 2 of the drawing. The carbon paper, ribbon or the like has a flexible one Backing 20 with a microporous ink-releasing layer of the squeeze type and a thin, non-transferable coating 24 on top of that ink-donating layer of one synthetic thermoplastic resin. The color-releasing

The layer has a non-transferable microporous resin structure 23, in the pores of which (droplets 22 of oily paint escaping under pressure are contained. The coating contains the incompatible liquid, oily substance in the form of uniform droplets 25 which form the areas of the coating which under the Imaging pressure allows ink to pass through, but does not allow ink to pass under weaker pressures. Thus, while imaging pressure is sufficient for the oily ink to emerge through droplets 25 onto a copy sheet, the weaker pressure exerted by a typewriter roller or the like is insufficient to allow the oily paint to penetrate through the oily droplets.

The for the production of the coating compositions according to the invention used, suitable ingredients can largely vary depending on the composition of the ink-releasing layer. So can the synthetic thermoplastic Resin binder a vinyl resin, for example a copolymer of vinyl chloride and vinyl acetate or a polymethyl methacrylate or a copolymer of the same with ethyl acrylate or a light vinyl resin, for example an alcohol-soluble polyamide (nylon), cellulose acetate butyxate or be a polycarbonate. Generally suitable

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each as a binder for the ink-releasing layer in embossing coming resin also for coating; in the German patents 1 178 091 and 1 169 968 as well as in the U.S. Patents 2,820,717, 3,037,879, 3,314,814 are suitable resins ".

Likewise, the oily substance of the coating can be the same as the incompatible dye carrier of the dye-releasing agent Layer and in the US patents mentioned above, suitable substances are listed. Liquid oily substances, for example, mineral oil, butyl stearate, silicone oil and the like are preferred. In sharp contrast to those in the color-donating layer used proportions where the amount of the oily color carrier is at least equal to the amount of resin, but is the liquid oily substance of the coating in one Amount of at most 0.8 parts by weight, based on the resin binder, present. Preferably the oily one makes liquid substance 0.3 to 0.5 parts by weight per part by weight of the resin binder. Oil: resin ratios in excess of About 0.3 give coatings that feel oily, the density of the copied image areas on your copy sheet with the achievement of uneven tints, and a parboil penetration of the parbe from the color layer on the copy sheet under lower than image-generating pressures, e.g. under the action of roller pressure, allow.

The wetting agent can be soluble in the volatile solvent used to apply the coating be anionic, cationic or non-ionic. Preferred substances are lecithin, sorbitan esters, e.g. Sorbitan sesquioleate and related E ^ ter commercially available under the name "Tween", dioctyl sodium sulfosuccuinate and related dialkyl salts that are commercially available

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are available under the trade name Aerosol, Polyoxyethylene compounds and the like.

The coatings according to the invention can optionally contain a small amount of a non-marking, hardly oil-absorbing pigment or filler for decorative Purposes included; this substance is expediently oleophobic, so that it is bound in the resin phase. Pigments, such as bronze powder are preferred. The amount k of this substance should not be about 5 wt. ^, based on the Dry weight of the coating. In all cases, however, the liquid, oily droplet phase is of the coating is essentially free of coloring matter and itself has no color transfer capacity.

The following example explains the production of a carbon paper according to the invention without affecting the invention however, it is limited to this.

A sheet of polyethylene terephthalate polyester approximately 0.013 mm thick (Mylar) is first coated with a thin layer of polyvinylidene chloride (Saran) dissolved in ^ Methyl ethyl ketone, to achieve a receptive first coating coated with a thickness of about 0.0025 mm. After evaporation of the solvent becomes the following paint is applied to this first coat:.

Components parts by weight

Styrene methyl methacrylate copoly-

. merisat (Zerlon 150) 12.0

Butyl stearate 7.0

Purified rapeseed oil 7.0

Sulphonated vegetable oil 1.7

Blue tint paste 2.2

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Components Weight point Black tint pigment 6.6 Ethyl acetate 10.2 Methyl ethyl ketone 26.3 toluene 27.0

100.0

The applied paint is at elevated temperatures dried to form a microporous paint layer approximately 0.015 mm thick.

As shown in Fig. 1, the carbon paper thus obtained then runs in contact with a pressure roller 13, so that the paint layer is provided with a thin layer of the coating compound contained in the trough 15. The following compositions 1 and 2 give examples of coating compositions that can be used:

Components Parts by weight 1 composition. 2 Together. 7th Polymethyl methacrylate 7th VJi Butyl stearate 2 - Siliconoel (Dow Fluid 556) 1 - Lecithin 0.5 88 Methyl ethyl ketone 89.5

The coating compound is given a preferred weight of ' 0.077 kg / ream applied to the ink-releasing layer. Then the carbon paper is used to evaporate the

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Methyl ethyl ketone leaving the dried polymethyl methacrylate structure in the form of a uniform Layer evaporated on the ink-releasing layer. The coating is then at least partially with the resin structure of the paint layer due to the solubility of the the latter solvent-bound in methyl ethyl ketone.

The finished film web is wound up on the take-up _{roll 19 and cut into sheets or tapes with the desired k} dimensions. The present invention relates primarily to the manufacture of carbon papers for typewriter purposes and of ribbons or wide ribbons for other office machines.

Although pigments such as carbon black, magnetic iron oxides, finely divided Dyes and tinted pigments can be used with the colors you want, yet are based on the Surface of porous pigments deposited and absorbed dyes with the desired color preferred coloring substances in the color layer; other coloring materials are also useful, including the almost colorless, color-forming reactive chemicals that react with other chemicals when they come into contact with them colorless chemicals present on the surface of the copy sheet, colored reaction products form.

For the purposes of the invention, two or more substances are compatible with one another if they are mixed in liquid form in the proportions used can form a single-phase solution. An oil is with Compatible with another oil if it forms a single-phase solution with this other oil mixes and does not separate when standing; an oil is with a semi-solid, e.g. lanolin, then

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compatible if it is liquefied by heating semi-solid mixed to form a single-phase solution and "did not materially" when cooled leaves it; an oil is compatible with a resin mix, when it is in a solvent together with the resin for both is dissolved and does not separate again from the resin on evaporation of the solvent. In many cases, substances are compatible with one another when used in certain relative proportions, while when these proportions are exceeded, a second, incompatible phase is formed. The present Invention includes the use of such substances, but only in such relative proportions, which result in compatible, single-phase solutions.

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Claims (1)

Claims Process for making squeeze type pressure sensitive carbon papers with a clean handle and without Color leakage under the action of pressures that are weaker than the image-generating pressures that occur under the action of an image-generating print, however, result in evenly tinted and very intense image areas, whereby a squeeze-out type pressure-sensitive ink layer having an ink-releasing surface and a non-print transferable microporous structure made of synthetic thermoplastic resin in the pores of which emerge under pressure and consist of an oily carrier and a coloring substance Color is located, characterized in that an evenly thin layer of a coating mass is printed on this color-releasing surface of the color layer, consisting of 1 'part by weight of a synthetic thermoplastic resin, up to about 0.8 part by weight of a liquid, incompatible with the resin ", but with that under pressure exiting Color acceptable oily substance and a predominant amount of a volatile solvent for _i the resin which also forms at least a partial · solvent for the resin of the color layer tool • is that one then the volatile organic solvent under solidification of the resin as a non- Pressure transferable coating in which the liquid oily substance is uniformly dispersed in the form of droplets, evaporated, these droplets of color from the color layer under the action of an image-forming agent 9.09881 / 1056 Allow pressure to pass through, but do not result in color transfer themselves. 2. The method according to claim 1, characterized in that the coating composition about 0.3 to about 0.5 parts by weight of the liquid oily substance to 1 part by weight of the resin. 3. The method according to claim 1 or 2, characterized in that that the synthetic resins of the paint layer and the coating compound contain acrylic resins. '.. 4. The method according to claim 1, characterized in that that the coating mass is applied in an amount by weight of about 0.045 to about 0.23 kg per ream. 5. The method according to any one of the preceding claims, characterized in that the coating composition also contains a wetting agent that reduces its surface tension and enables the application of a thin coating layer with greater uniformity 6. Pressure-sensitive carbon paper or the like of the squeeze-out type with a clean grip and resistance to a color leakage under the influence of minor as image-forming press consisting of one flexible carrier with a color layer of a non-transferable microporous, synthetic thermoplastic Resin structure, in whose pores ^ a sub It contains pressure leaking ink consisting of an oily carrier and coloring substance, characterized in that this layer has a thin, non-pressure transferable coating is connected, - ■ '.'? 8 8-1 / -tO 5-6 · ' that of one part by weight of a synthetic thermoplastic Resin and up to 0.8 parts by weight of a liquid oily substance, which with the resin incompatible, but compatible with the color emerging under pressure and uniform in the coating is dispersed in the form of droplets that under the action of image-forming pressures color from the ) Allow the color layer to penetrate, but not have any coloring power itself. 7. carbon paper or the like. According to claim 6, characterized in that that the synthetic resins of the paint layer and the coating contain acrylic resins. 8. carbon paper or the like. According to claims 6 or 7, characterized in that the, coating of ejwa 0.3 to about 0.5 parts by weight of the liquid oily matter per 1 part by weight of the resin. 9. carbon paper or the like. According to claims 6 or 7, * characterized in that the cover has a weight from about 0.045 & g "to about 0.023 kg / ream. 10. carbon paper or the like. According to claims 6,7,8 or SU characterized in that the coating is still a Contains wetting agents. 909881/1056