HU181996B - Method for producing pressure sensitive copying material - Google Patents

Description

The present invention relates to a process for the production of pressure sensitive media.

Known as a widespread "transfer" method, the copying method comprises applying microcapsules containing a solution of a colorless colorant material on the lower surface of an inner sheet, and a dye-developing material such as an acidic mildew or phenolic resin on the upper surface of the lower sheet. in. In most cases, a few intermediate sheets are used, each with a microcapsule bottom surface and a dye developer top surface. When printing or typing on the sheets, the pressure breaks the microcapsules, whereby the coloring solution reaches the dye-producing material of the nearest bottom sheet, and a chemical reaction occurs between them, which produces the color of the coloring material.

These systems have the disadvantage that at least two types of coated sheets (usually three types) have to be produced, i.e. an upper sheet, a lower sheet and an intermediate sheet as mentioned above.

To overcome this disadvantage, the so-called The use of a 'self-supporting' system was recommended. In this system, the microcapsules and dye-developer material are applied to the same surface of a sheet, and writing or typing on another sheet on the thus-coated sheet breaks the capsules, releasing the colorant, which is then applied to the sheet. react and produce discoloration.

The disadvantage of the "self-supporting" system so far has been that the sheet had to be produced in a two step coating process. In the first step, a coloring agent encapsulated in the microcapsules was applied to the sheet, and in the second step, a second dye-developing material was applied to the same sheet.

Obviously, it would be simpler and therefore cheaper to apply the microcapsules and the dye developer simultaneously in a single step. For example, U.S. Patent No. 2,730,457 proposes such a method. However, it is our experience that in such cases premature color formation occurs, even when the microcapsule suspension is mixed with the color developer dispersion prior to lubrication and even after lubrication.

The causes of premature color formation are complex and unclear. One reason for the premature color formation is that the conventionally prepared microcapsule suspensions also contain a certain amount of non-encapsulated coloring solution which reacts rapidly with the dye developer during dye formation. However, it has been found that premature color formation can occur even in the absence of an unencapsulated coloring solution, for example removed from the suspension prior to mixing with the color developer. Of course, this would probably make production extremely expensive on an industrial scale. The cause of this premature color formation is unknown, but our studies indicate that there is a mutual attraction between the capsules and the particle-13 of the color developer. It is unclear how this attraction causes premature color formation.

As mentioned above, even if a colorless mixture is obtained, the paper may color immediately after lubrication either immediately upon drying or a few days after lubrication. The cause of the premature discoloration of the self is also unknown.

It has been found that the use of certain mineral coloring agents can substantially prevent or at least reduce the above-mentioned color formation phenomena by subjecting the coloring agent and, if appropriate, the microcapsules to suitable chemical treatment.

The material used for this chemical treatment is hereafter referred to as a protective agent.

SUMMARY OF THE INVENTION An object of the present invention is to provide a "self-supporting" pressure-sensitive media by lubricating a sheet, such as a sheet of paper, with a coating material consisting of a mineral color developer and a solution of a colorant incorporated in microcapsules to form a colorant. the particles of the color developer material and optionally the microcapsules are treated with a protective agent which prevents premature color formation, is compatible with the microcapsules and does not affect the developer properties of the color developer material.

Protective agents used with certain types of microcapsules leach the contents of other types of microcapsules. Therefore, it is important that the protective agent used is compatible with the particular type of microcapsules. Incompatible protective microcapsule combinations are discussed below.

A suitable mineral coloring agent is, for example, an acidic chemical such as Japanese acidic clay produced in Japan. 3

The mineral coloring clay is treated with the preservative by simply mixing its suspension with the preservative. The mixture may be allowed to stand, optionally with stirring.

The protective agent may be a self-crosslinkable polymer. In this case, it may be advantageous to heat the mixture of polymer and color developer prior to mixing with the microcapsules.

It is preferred that the color developer and, if desired, the microcapsules are treated prior to mixing.

If premature color formation does not occur immediately upon mixing, the protective agent may be added to the system after mixing.

Not only polymers with a high degree of polymerization but also low molecular weight so-called "crosslinked polymers". also include prepolymers or precondensates.

By "self-curing" polymer is meant resins or precondensates used in the paper industry to increase the wet strength of paper. Preferred such materials are epichlorohydrin and aminoplast resins or precondensates. For example, epichlorohydrin resins marketed under the trade names "Nadavin FP", "Nadavin FPN", which are polyaminoepichlorohydrin resins, "Nadavin LT", a polyamide-polyamino-epichlorohydrin resin, are all manufactured by Bayer U.K. Ltd. Most preferably, "Nadavin FP" can be used. Suitable aminoplasts, such as melamine formaldehyde resins or precondensates, or urea formaldehyde resins or precondensates. Of the aminoplasts, melamine-formaldehyde condensates are generally the most effective in preventing premature color formation. A suitable melamine-formaldehyde resin is, for example, Beetle BC 27 resin sold by British Industria Plastics Limited. BC 27 has a reactive resin content of about 100% and a solids content of ca. 93%. Suitable melamine-formaldehyde precondensates are BC 71, BC 309 and BC 336 Beetle resins, which are also available from British

Manufactured by Industrial Plastics Limited and which are methylated modified melamine formaldehyde precondensates. The BC 71 is approx. 80% reactive resin and ca. Made with 69% solids. The BC 309 reactive material contains approx. 90% solids content ca. 80%, the reactive content of BC 336 is approx. 76%, solids content ca. 71%.

Other usable aminoplasts are urea formaldehyde L 5084 and urea formaldehyde precondensates BC 6, also manufactured by British Industrial Plastics Limited. The former has a reactive resin content of 70%, a solids content of 68%, and the latter has a reactive resin content of ca. 50% solids content ca. 45%. Other self-curing polymers that can be used as protective agents include the Hercules Powder Company under the trade names Kymene 709 and 5 Kymene 557 and Napcobond SWS-10 by Diamond Shamrock Corporation.

When a self-crosslinkable polymer is used as a protective agent, the manner in which the color developer is treated depends to a large extent on the material quality of the polymer. Choosing the right treatment method is not a problem for the skilled technician. For example, acid clay as a color developer and melamine-formaldehyde pre-condensates BC 27 and 5 BC 71 may be treated with about 10% resin or pre-condensate in a 10% solution. It is treated for 2 hours at 90 ° C (concentration in% by weight based on dry clay). Kezelés Suitable treatment with polyamine epichlorohydrin resins and acidic clay color developer, for example, is by mixing the clay with a 10% aqueous resin solution and then stirring the mixture at pH 7-8 for a few minutes. No heating required.

In some cases, the capsules may also be advantageously treated with a self-crosslinking polymer, suitably with the same crosslinkable polymer used to treat the color developer.

Solvents which are non-crosslinkable polymers such as BASF Polymin P resin can also be used to increase the wet strength of the paper.

Other agents that can be used as protective agents are anionic surfactants, especially those containing sulfate and sulfonate groups. Examples of such sulfate-containing surfactants include the lauryl sulfate salts such as sodium lauryl sulfate. Examples of sulfonate-containing surfactants include dodecylbenzenesulfonic acid salts, dibutyl ester of sulfobenzoic acid (e.g. Manoxol 1B from C BDH Chemicals Limited, dioctyl ester of sulfobuccinic acid (e.g. ), sulfonate ricinoleic acid derivatives (e.g. Glanzol CDF or Glanzol 100 from Steiner Zschimmer and Schwarz of Lahn-2181996) Glanzol CDF is primarily recommended as a lacquer softener, but can also be used as a surfactant. examples of anionic surfactants which do not contain sulfonate groups and which can be used as protective agents are ethylenediaminetetraacetic acid (EDTA).

Examples of anionic surfactants other than Glanzol CFD that may be used as protective agents include dibutyl phthalate, di-2-ethylhexyl adipate, dibutyl maleate and tris (Livenol).

7-9) -trimetiiitát. However, they have the disadvantage that they form oily stains on the coated sheet and are therefore not recommended.

Other protective agents include fluorine-containing hydrophobic agents used in the paper industry. Examples include DuPont's Zonyl RP or Zonyl NF products and 3M's Scotchban FC 807.

If desired, a mixture of different protective agents may be used. In some cases, the use of such mixtures provides certain advantages over the individual components. The combination of the fluorine-containing papermaking aids and the aforementioned Kymene resins provides better protection than these components alone.

The amount of protective agent depends on the quality of the capsules and coloring agent used, usually 5-10%. The optimum amount can be determined by one skilled in the art without difficulty. In this regard, the following embodiments of the description will provide information.

Capsules of "self-supporting" pressure sensitive copying systems generally have a thicker wall, i.e., stronger than those of the more widely used transfer system capsules described above. This is also the case with the "self-supporting" copying systems produced by the present process when it is desired to produce a product with the appropriate properties. The manufacture of strong-walled capsules for "self-supporting" pressure sensitive copying paper is well known to those skilled in the art, but will be discussed in our working examples.

Although it is advantageous to use stronger-walled capsules than those commonly used in transfer system pressure-sensitive copying systems, transfer-type capsules are slightly less prematurely (too early) when the color developer is treated with the self-crosslinking polymer before it would be mixed with the microcapsule suspension. However, the resulting product may still be too colorful to be used in practice.

The material of the microcapsules of the invention may be made, for example, of melamine-formaldehyde resin, urea-formaldehyde resin and an acrylamide-acrylic acid copolymer as described in U.S. Pat. United Kingdom Patent No. 5,529,427 proposes or may be made of a urea-formaldehyde polymer as disclosed in German Patent Publication No. 2,529,427. Other synthetic materials that can be used for this purpose include polyacrylates, polyurethanes, and other polyurea or aminoplasts. The capsule wall may also be made of coacervated hydrophilic colloids such as a mixture of gelatin, gum arabic or carboxymethylcellulose (CMC) and polyvinylmethyl ether maleic anhydride copolymer (PVM / MA), as described in British Patent No. 870,476. In order to be strong enough, the "self-supporting" copy paper capsules must have a phase ratio that is less than the phase ratio used to make transfer-type pressure sensitive copying systems (phase ratio to weight ratio of colorant solution to capsule wall content of aqueous solution). At lower phase ratios, thicker-walled capsules are obtained than larger capsules. In the case of transfer-type capsules, the process of the present invention produces less blue coloration than without the use of a protective agent, but the blue coloration may still be too large to be practically acceptable.

Capsules of aminoplast synthetic wall material generally have a stronger wall and less permeability than gelatin coacervates. Therefore, Synthetic Wall Capsules are less prone to blue premature formation than gelatin-coacervate-type capsules. However, previous studies have found that it is advantageous to protect synthetic wall capsules, even if there is only a slight difference in whiteness between the protected and unprotected copy papers. Because the eye can sense small differences in whiteness degrees, which can greatly affect the chances of the paper market.

Not all of the protective agents listed above can be used with all capsule types. Anionic surfactants, for example, leak out the contents of gelatin coacervate wall capsules, but are well suited for aminoplast synthetic wall capsules. It is easy for one skilled in the art to select a barrier material compatible with the capsules of the particular wall material.

Some protective agents are not suitable for this purpose. For example, prior art studies have found that cationic or nonionic surfactants, which are considered to have the same effect as anionic surfactants, "poison" the color developer and prevent it from exerting its developer effect in a proper manner. In practice, retention aids used in the paper industry, which are chemically similar to wet strength agents, have been found to cause flocculation of coating dispersions. There are probably ways to avoid the above difficulties.

The process of the present invention is not limited to certain coloring agents or certain solvents thereof. Suitable coloring agents include, for example, phthalide derivatives such as crystal violet lactone, fluorane derivatives, diphenylamine derivatives, spiropyran derivatives, phthalimidine derivatives and benzoyl leuco derivatives of various dyes. As is well known in the art, mixtures of various coloring agents may be used. Suitable solvents are, for example, partially hydrogenated terphenyls, chlorinated paraffins, biphenyl derivatives, diarylmethane derivatives, alkylnaphthalenes, mixtures of dibenzylbenzenes, phthalate or phosphate esters of linear alkylbenzenes having from 10 to 14 carbon atoms. Mixtures of solvents with diluents such as kerosene may also be used.

If the capsules and the color developer are to be treated with a protective agent, the conditions of the capsule treatment will be determined by the quality of the materials used. The circumstances can be selected by one skilled in the art. The export examples provide guidance in this regard.

To improve the rheological properties of the coating material and the whiteness of the coated sheet, the coating material may also contain fillers. Suitable

-3181996 fillers are kaolin and calcium carbonate. As is known, these fillers sometimes cause slight discoloration. This coloration is not significant, but if desired, the filler may be treated with a protective agent under the same conditions as the color developer. Kaolin, for example, is treated in the same way as color developing acidic clay.

Care must be taken when selecting the appropriate binder for attaching the coating to a sheet of paper. Some of the binders commonly used in the production of transfer-type pressure sensitive copy papers may have a color developer or other undesirable effect and are therefore unsuitable for this purpose. Thus, for example, starch as a binder may reduce the reactivity of the color developer, probably because it forms a film on the surface of the particles of the color developer. It has now been found that highly hydrolyzed polyvinyl alcohol is a particularly suitable binder for preparing the coatings of the present invention.

The coating material may also contain a dispersant which conveniently controls its pH. Examples of such dispersants are sodium silicate and sodium hydroxide. Each of these also controls the pH. The optimum pH is determined by the color development reaction. Thus, if one of the coloring agents is crystalline violetactone and the coloring agent is an acidic clay, the pH is preferably adjusted to 10.

The coating material may contain, in addition to the above components, a protective agent which is well known in the pressure sensitive copy paper industry during storage and handling, and is not further discussed. Suitable materials include cellulose sludge flakes and wheat starch granules.

The copying paper produced by the process of the present invention has a dry weight of about 10-15 g / m ² . Coating can be done with lubricating blade, air blade or lubricating cylinder technology. Conventional capsule coatings have not been lubricated with lubricating blade technology in the industry so far because economical low coating weights cannot be achieved with a sufficiently uniform coating. The process of the present invention facilitates the use of a lubricating blade because the color developer present along with the microcapsules increases the weight of the coating. The ability to use lubrication blade technology offers an advantage in terms of the speed of the operation available and the capacity of the lubricator. The mechanism by which the protective agent prevents premature color formation in the coating is not known. It is believed that such protective agents reduce the mutual attraction between the coloring agent and the microcapsules, but other theoretical explanations for the phenomenon are also possible.

1 and 2 are attached to illustrate the invention. Figure 1 is an enlarged cross-sectional view of a pressure-sensitive copy paper made by the process of the invention, and Figure 2 is an operating block diagram of the process of the invention.

Fig. 1 illustrates a paper sheet carrier 1 having a coating layer 2 containing microcapsules 3 and color developer 4. The other components of the coating layer are not shown in the figure. Such an additional component is the protective agent, however, it is not known where its particles are located within the coating layer.

The operating block diagram of Figure 2 illustrates that in the process according to the invention, the coating material, the microcapsule suspension, the filler, the binder, the dispersant, the pH adjusting agent are mixed. Prior to mixing, the coloring agent and optionally the microcapsules and / or filler are treated with the protective agent. If desired, the filler may be mixed with the color developer prior to treatment with the protective agent. In Figure 2, the alternate sequence of operations is indicated by a dashed line. The coating material is then applied to the paper support and dried. In this way, the coated product shown in Figure 1 is obtained.

The invention is further illustrated by the following examples.

Example 1

(a) Production of capsules

382 g of a 9.1% gelatin solution having a pH of 6.4 are filled into a blender mill. At low speed, 274 g of the internal phase, i.e. the substance to be encapsulated, is added to the solution. In this case, the internal phase is a 9: 1 mixture of Dobane JN (Shell, C10-C14 open-chain alkylbenzene blend) and Santicizer 711 (phthalate sold by Monsanto), which is 1.8 wt% crystalline violetactone and Contains 1.4% by weight benzoyl-leukomethylene blue. The mixture was milled until the droplet size dropped below 3 am.

17.6% by weight of gum arabic water (17.6% by weight) and deionized water (422g) were added to 218g of the gelatin solution / inner phase emulsion prepared above. The pH of the mixture was adjusted to 8.7 with NaOH, and 8 g of 5% w / w aqueous polyvinylmethyl ether maleic anhydride (PVM / MA) was added slowly.

The pH was then lowered to 4.3 with 14.7% acetic acid. Meanwhile, a coacervate precipitates and coats the inner phase droplets. The emulsion was cooled to 10 ° C and 3.3 ml of 50% glutaraldehyde was added to crosslink the coacervate.

To prevent capsule agglomeration, an additional 10 g PVM / MA followed by 6 g buffer

An aqueous solution of 12.5% by weight of sodium carbonate is added. The pH is then slowly raised to 10 with sodium hydroxide.

b) Preparation and Application of the Coating Agent G acidic color developer clay (Silton M-AB of Mizusawa, Japan) is dispersed in water so that the solids content of the dispersion is ca. 36%. To this dispersion was added 3 g of BC 71 melamine-formaldehyde precondensate as a preservative. The resulting slurry was heated to 90 ° C with stirring, kept at this temperature for 2 hours, and then cooled.

g Dinkie clay A is then cured for approx. Disperse to 36% solids with water. 1 g of BC 71 melamine-formaldehyde pre-condensate was added as a preservative, the slurry was heated to 90 ° C, kept at this temperature for 2 hours and then cooled.

The treated Silton and Dinkie clays were mixed-4181996 and adjusted to pH 10 with NaOH.

132 ml of the capsule suspension prepared as described above is then added to the clay slurry and 30 g of 10% polyvinyl alcohol (PVOH) binder (Moviol 56-98 from Harlow Chemical Co. Ltd.) is added. The resulting mixture is applied to a paper weighing 49 g / m ² with a laboratory lubricator and, after drying, the paper whiteness is measured with a turbidity meter (e.g., Bausch and Lomb's U.S. Patent No. 1,950,975 or Diano BVL 2 turbidity meter). During the test, the reflectance of the sheet against a standard white surface (magnesium oxide powder coated surface) is measured. The result is given by the reflectance of the test sheet x 100) the reflectance of the standard white surface. The higher the ratio, the whiter the coated sheet tested. Measurement is performed at various locations on the test sheet and the measurement results are averaged. A few percent differences may not seem significant at first glance, but such differences are noticeable and can have a major impact on trading opportunities.

The copy paper made in this manner had a 93% background radius and appeared white. If you put a regular piece of paper on this copy paper and write on it, the coated sheet will produce a sharp image of the writing.

To demonstrate the efficacy of the malemin-formaldehyde precondensate, a similar experiment was performed without pretreating either Silton or Dinkie clay with melamine-formaldehyde precondensate.

g of Silton M-AB clay and 10 g of Dinkie Clay A were dispersed in water to give an amount of ca. A dispersion of 40% solids was obtained. The pH of the dispersion was adjusted to 10 with sodium hydroxide solution.

132 ml of the capsule suspension prepared above and 30 g of 10% polyvinyl alcohol binder (Gohsenol NH 26 from Nippon Synthetic Chemical Industry Co. Ltd., Japan) are added.

The resulting mixture is light blue in color and is also light blue in color when applied to paper at 9 g / m ² with a background radiation of 81%.

Example 2

This embodiment illustrates the use of various self-crosslinkable polymers as protective agents.

g Nadavin FP is dissolved in 60 g water. In this solution, 30 g of Silton M-AB acidic coloring clay and 10 g of Dinkie clay A are dispersed. To prevent flocculation, 2 g of a 1% Dispex N 40 solution (a 1% solution dispensed by Allied Colloids Ltd.) is added to the dispersion. The pH was raised to 10 by slow addition of sodium hydroxide solution.

132 ml of capsule suspension prepared as described in Example 1 was then added, followed by 30 g of 10% polyvinyl alcohol binder (Moviol 53-98).

The resulting blend is very light blue, 8 g / m ² coated paper is also pale blue with 87% background radiation. This is an improvement over the untreated Silton Clay Coating described in Example 1, which has a background radiation of 81%. The background radiation of the copy paper produced in the experiment with another syncoping solution and treated Silton clay is 88%.

If you place and write on a piece of plain paper on copy paper made in the above manner, the coated sheets will produce a clear blue copy of the writing.

Example 3

(a) Production of capsules

Mix:

g approx. 45% reactive resin and ca. BC 77 cationic urea-formaldehyde resin (manufactured by British Industrial Plastics Limited), 35% solids, g R 1144 (20% solution of acrylamide-acrylic acid copolymer by Allied Colloids Limited; average copolymer weight 40,000, acrylic acid) content 42%),

200 g deionized water.

The mixture was heated to 55 ° C and maintained at this temperature for 45 minutes. 12 g of BC 336 melamine-formaldehyde precondensate were added and the pH was reduced to 4.4 with acetic acid.

89 g of a coloring agent solution are then added and the dispersion is ground to a droplet size of 4-5 μηι. Then, 20 g of deionized water was added, the mixture was stirred at 35 ° C for 1 hour, then at 55 ° C for an additional 2 hours and then allowed to cool to room temperature overnight. In the morning, the pH of the mixture was raised to 10 with 10% sodium hydroxide solution. The resulting capsule suspension has a solids content of about 10%. 30%, phase ratio 3.4: 1.

b) Preparation and Application of Coating Material Silton M-AB acidic coloring clay is suspended in water so that it is diluted with ca. A slurry of 40% solids was formed. 1.5 g of BC 71 melamine-formaldehyde precondensate are added as a preservative. The mixture was then heated to 90 ° C for 2 hours and then allowed to cool. The pH is adjusted to 10 with sodium silicate.

ml of capsule suspension (dry weight of capsule: 5.5 g) was mixed with 0.55 g of BC 71 melamine-formaldehyde resin as a preservative, heated to 70 ° C for 1 hour and allowed to cool.

The treated color developer clay dispersion and the treated capsule suspension were mixed and 15 ml of 10% polyvinyl alcohol (Gohsenol NH 26) was added with stirring followed by 15 g of kaolin (Dinkie "A").

The resulting mixture is applied to a sheet of paper as described in Embodiments 1 and 2 with a coating weight of 12.5 g / m ² . The whiteness of the sheet of paper was measured and found to be 93.5% on average. When a conventional sheet of coated paper is placed on it and overlaid with normal pressure, a clean copy of the sheet is formed on the coated sheet.

days later, the whiteness of the sheet is re-measured and an average of 88% is obtained.

-5181996

Example 4

(a) Production of capsules

The procedure described in Example 3 was repeated except that 40 g of deionized water and 10 g of BC 336 prepolymer were added to the mixture after the addition of the sintering solution and grinding. In the following, the procedure of Example 3 is followed.

b) Preparation and Application of Coating Material Silton M-AB acid dye developer clay is dispersed in water in an amount such that the solids content of the dispersion is 40% and 2.0 g BC 71 melamine-formaldehyde precondensate is added as a preservative. The mixture was then heated to 90 ° C, held at this temperature for 2 hours and allowed to cool. The pH is then adjusted to 10 with sodium silicate.

g of kaolin (Dinkie "A") is dispersed in water in such a quantity that the solids content of the dispersion is ca. 50% and 1.5 g of BC 71 melamine-formaldehyde precondensate is added as a protective agent. The mixture was then heated to 90 ° C for 2 hours and then allowed to cool.

The treated color developer clay dispersion and the treated kaolin dispersion are then mixed.

ml of capsule suspension (dry weight of capsule

5.8 g) 0.58 g of BC 71 melamine formaldehyde pre-condensate as a preservative are added, the mixture is heated to 70 ° C, maintained at this temperature for 1 hour and allowed to cool. The resulting capsule suspension is then added to the treated clay dispersion.

Then 15 ml of 10% polyvinyl alcohol (Gohsenol NH 26) was added with stirring.

The resulting mixture is then spread on a sheet of paper as described in the previous embodiment, except that the amount of coating is 14 g / m ² . The whiteness of the sheet was examined and found to be 97%. When a plain sheet of paper is placed on the resulting sheet and printed with normal compression, a clear blue copy is produced on the coated sheet.

After a day, the degree of whiteness measurement was repeated and a mean of 96% was obtained.

Example 5

Capsules prepared as described in Example 4 are used except that they are not treated with melamine-formaldehyde precondensate.

g Silton M-AB acid color developer clay is dispersed in water so that the solids content of the mixture is ca. 40% and then as a protective agent

1.5 g of BC 27 melamine-formaldehyde resin are added. The mixture was heated to 90 ° C, held at this temperature for 2 hours, and allowed to cool. The pH is adjusted to 10 with sodium silicate.

ml of capsule suspension (dry weight of capsule

5.8 g) followed by 15 ml of 10% polyvinyl alcohol (Gohsenol NH 26) and 15 g of kaolin (Dinkie 'A') are added with stirring.

The resulting mixture is then applied to a sheet of paper as described in the preceding embodiments, except that the coating weight is 13.6 g / m ² . The whiteness of the sheet was measured to give an average value of 96.5%. When you place a sheet of plain paper on this sheet and write at normal printing, the coated sheet produces a clear blue copy.

day, the whiteness measurement is repeated. An average of 96% is obtained.

Example 6

The capsules were prepared as described in Example 4 except that they were not treated with melamine-formaldehyde precondensate.

g Silton M-AB is suspended in water so that the solids content of the dispersion is ca. 40%. The pH is then adjusted to 10 with sodium silicate. The dispersion is then divided into two portions, one of which is treated with BC 71 melamine-formaldehyde precondensate as a preservative as described in Example 4.

ml of capsule suspension (capsule dry weight about 7 g) followed by 15 ml of 10% polyvinyl alcohol (Gohsenol NH 26) to each of the clay dispersion portions with stirring. The colorless mixtures thus obtained are spread on a sheet of paper with a coating weight of 8 g / m ² as described in the previous examples. The color of the sheet coated with the treated clay dispersion is white with 95% background radiation and the background radiation with the untreated clay dispersion 91%.

By placing ordinary sheets of paper on the coated sheets thus produced and printing on them under normal pressure, a blue copy is produced on both coated papers, but on the treated clay dispersion the copy is clearer.

after day 3, the background radiation measurements are repeated. The background radiation of the untreated clay dispersion sheet is 85% and that of the treated clay dispersion 92%.

Example 7

This embodiment illustrates the use of an amino epichlorohydrin resin as a protective agent instead of a melamine-formaldehyde resin or precondensate.

The capsules were prepared as described in Example 4 except that they were not treated with melamine-formaldehyde condensate.

g Silton M-AB acid dye developer clay is dispersed in water containing 1.5 g of Nadavin FP aminoepichlorohydrin resin (protective agent) to give a solids content of about 1 g. 30%. The pH was adjusted to 8 with sodium hydroxide and the mixture was stirred at room temperature for several minutes. The pH is then adjusted to 10 with sodium hydroxide.

7 ml of a capsule suspension containing 7 g of dry solids was added followed by 15 ml of 10% polyvinyl alcohol (Gohsenol NH 26) with stirring. The resulting mixture is applied on a sheet of paper at a rate of 8 g / m ² . The coated sheet is white and has a light reflectance of 93%.

If we put a piece of ordinary paper on this coated sheet and write it under normal pressure,

-613 then produces a sharp blue copy of the writing on the coated sheet of paper.

days later, the whiteness of the sheet was re-measured and found to be 92.1%.

Note that Navadin resin does not need to be heated as the melamine-formaldehyde resins discussed above. In this case, the possibility of formaldehyde vapor formation is minimized.

Example 8

This embodiment illustrates the production of the pressure-sensitive copying paper of the present invention on a plant (and not a laboratory coating machine).

(a) Production of capsules

The preparation is carried out using a 2.7: 1 phase ratio as follows:

Add 16.8 kg of acrylamide-acrylic acid copolymer R 11 kg to hot deionized water and raise the temperature to 55 ° C. 7.6 kg of BC 77 urea-formaldehyde resin were added and the mixture was stirred for 40 minutes while maintaining the temperature at 55 ° C. thereafter

8.9 kg of BC 336 melamine-formaldehyde precondensate are added and the pH is adjusted to 4.4 with acetic acid. Subsequently, 36.4 kg of a coloring solution are added to the system and the resulting dispersion is ground to a droplet size of 4-5 μιη. The pH was adjusted to 4.0 with acetic acid, and the mixture was heated at 55 ° C for 3 hours. The pH was adjusted to 10 and the mixture was stirred overnight. The capsule emulsion has a solids content of 29.5%.

b) Preparation and application of the coating material

50 kg Silton M-AB are dispersed in 83.2 liters of water. Then, 5 kg of BC 71 melamine-formaldehyde pre-condensate was added as a protective agent and the mixture was stirred at a temperature above 90 ° C for 2 hours. The mixture was then filled into a rod mill and the process was repeated after adding an additional 50 kg of Silton M-AB.

100 kg of Dinkie Clay A are treated in the same manner as Silton M-AB and this suspension is poured into the rod mill.

Then, 13 kg of 50% sodium silicate were added and the resulting clay slurry was transferred to a storage tank.

Dissolve 11 kg of polyvinyl alcohol (Gohsenol NH 26) in 113.4 L of water. To dissolve, the water is heated to 90 ° C and the solution is poured into another rod mill.

Subsequently, 121 liters of capsule suspension (dry weight: 47 kg) prepared as described under (a) was placed in a mixing vessel, 4.7 kg of BC 71 melamine-formaldehyde precondensate was added as a preservative, mixed and stirred at 70 ° C for one hour. Heat at C. The mixture is then added to a polyvinyl alcohol solution filled in a rod mill. After mixing, this mixture is added to the clay slurry placed in the storage tank.

After overnight resting (storage), spread the dispersion on a sheet of paper using an air knife lubricant as shown in Figure 8.

in different thicknesses. Table 8 also shows background radiation data for coated sheets of paper so coated.

Table 8

Coating weight (g / m ² ) _r 17.0 17.0 16.7 8.3 16.7 14.0 14.7

Average background radiation (%)

95.9 96.2 97.0 96.4 96.9 95.3 96.7

When a plain sheet of paper was placed on the coated sheets of paper and overwritten with normal pressure, the coated sheets had a sharp blue print.

days repeated for the sheets, the measurement of the degree of whiteness and yield was 94.0% of the mean value for the 14.0 g / m ² coating weight paper.

one month later, the measurement was repeated, and the sheet of paper coated with 14.0 g / m ^{2 had} a mean value of 93.4%.

Example 9

This embodiment illustrates a process size version of a lubricant, but in this case, a crosslinkable polymer of a different quality from that described in the previous embodiment is used.

(a) Production of capsules

The capsules were prepared as described in Example 8.

b) Preparation and Application of Coating Material Dissolve kg Nadavin FP as a preservative and 50 g Dispex N 40 in 65.7 liters of water in a rod mill. 75 kg of Silton M-AB and 25 kg of Dinkie A are dispersed in the solution. The pH is slowly adjusted to 10 with 14% sodium hydroxide solution.

178 kg of capsule suspension (dry weight: 55 kg) prepared as described under a) is added to the clay slurry. Then, 30 kg of Dow 620 Iatex binder (dry weight 15 kg) was added and after mixing the mixture was transferred to a storage tank.

The mixture is applied to a sheet of paper of various thicknesses shown in Table 9 using an air knife lubricator.

The coated sheets are placed on a plain sheet of paper and stamped with normal pressure. The coated sheets produce a sharp blue print.

Table 9

Coating weight (g / m ² ) 5 4 6

Average Background Radiation (%) 96 96 97 days, the whiteness measurements were repeated. An average of 96% was obtained for 6 g / m ² coated paper.

-7181996 weeks, measurements were repeated again, and 96% gave an average value of 6 g / m ² coating weight COPY PAPER.

Example 10 g Silton M-AB clay and 3 g Dinkie A-kaolin are dispersed in 20 ml water and a protective agent is added. The pH is slowly adjusted to 10 with sodium hydroxide solution. 38 ml of a microcapsule suspension of 17.5% solids (prepared as in Example 1) and 10 g of 10% polyvinyl alcohol binder (Moviol 56-98) are then added. The resulting mixture is then applied in a quantity of 10 g / m ² onto a sheet of paper weighing 49 g / m ² . After drying, the background radiation of the various portions of the paper is measured with an opacimeter, and averaged. The results are shown in Table 10, together with the results of the control experiment (in which no protective agent is used). 20

Table 10

Quantity of preservative and amount of clay used Background radiation (%) initial After 10 days was not (control) 84.5 81.8 Nadavin FP (10%) 87.8 85.1 Polymin P (10%) 91.3 90.7 Zonyl RP (10%) 91.2 89.7 Manoxol JB (10%) 89.4 83.5 Kymene 709 (5%) Zonyl RP (0.5%) 88.8 84.2

A plain sheet of paper is placed on each of the lubricated sheets of each of the mixtures containing the protective agent and overlaid on it. In each case, the coated sheets of paper produce a clear blue copy ·

Example 11

(a) Production of capsules

To 170 g of deionized water was added 42 g of copolymer R 1144 and the mixture was heated to 55 ° C. 19 g of BC 77 resin were added and the mixture was heated at 55 ° C for 40 minutes. Thereafter, 105 g of deionized water and then 179 g of a coloring solution are added. The resulting dispersion

Grind to a size of 4 to 5 μπι eseppm and then cool to 15 ° C.

g of BC 336 precondensate and 125 g of deionized water are then added and the pH of the dispersion is adjusted to 4.15 with acetic acid. The temperature was maintained at 15 ° C for one hour, then raised to 55 ° C and maintained at this temperature for 2 hours. Finally, the pH was raised to 8.5 with sodium hydroxide solution.

b) Preparation and application of the coating material

22.5 g of Silton M-AB clay and 7.5 g of Dinkie "A" kaolin are dispersed in 40 ml of water and a protective agent is added to the dispersion. The pH is slowly adjusted to 10 with a solution of sodium hydroxide solution. Then, 65 ml of a 30% solids microcapsule suspension prepared as described above was added. Subsequently, 22.5 g of wheat starch (Keestar 328, manufactured by Staley Starch Company) and 15 g of latex binder (commercially available as Dow Chemical 620 Latex) are added to prevent premature disintegration of the capsules. The resulting mixture was spread on a weight of 49 g / m ² paper material of 10 g / m ² weight.

After drying (105 ° C for about 20 seconds), the background radiation of the sheet prepared as described above is determined by means of an opacimeter and the values averaged. The results are shown in Table 11 below along with the results of the control experiment (no protective agent is used).

Table 11

Preservative and its amount calculated on clay Background radiation (%) initial After 10 days was not (control) 93.2 92.6 Nadavin FP (10%) 95.0 93.9 Glanzol CFD (10%) 95.1 94.1 Kymene 557 (5%) Zonyl RP (0.5%) 94.7 93.3 Polyethylene emulsion (for dry matter calculated on 10% polyethylene content) 95.1 93.9

Each coated sheet is placed under an ordinary sheet of paper and the latter is written over it. The coated sheets produce a sharp blue copy of the writing.

Example 12

The procedure described in Example 11 is repeated, except that various anionic surfactants are used as protective agents. For comparison, an experiment was performed with Nadavin FP and Glanzol CFD and, as a control, an experiment in which no preservative was used. The results are shown in Table 12 below:

Table 12

Protective and clay based, quantity used Background radiation (%) initial After 10 days was not (control) 93.3 92.1 Nadavin FP (10%) 95.3 94.5 Glanzol CFD (10% 95.0 94.5 Dodecilbenzolszulfonsav- (10%) - -sodium 95.1 94.5 EDTA (10%) 95.9 94.3 Manoxol IB (10%) 95.9 95.3 Manoxol 1T (10%) 95.1 94.5 Sodium lauryl sulfate (10%) 95.3 94.7 Triton GR 5 (10%) 96.3 95.9 Nopcote C 104 (10%) 94.7 94.1

-817

181) 66

Each type of coated sheet of paper was placed on, and written on, a plain sheet of paper. In each case, the coated sheets produced a sharp blue copy of the writing.

Example 13

22.5 g of Silton M-AB and 7.5 g of Dinkie A-kaolin are dispersed in water and a protective agent is added. The pH is slowly adjusted to 10 with sodium hydroxide solution. 65 ml approx. A microcapsule slurry containing 30% solids (prepared as described in Example II), 22.5 g Keestar 328 wheat starch granules and 15 g Dow 620 latex binder are added.

The mixture was spread on a weight of 49 g / m ² paper material of 10 g / m ² weight.

After drying, the background radiation of the various sections of the sheet of paper is measured with an opacimeter, and the measured values are averaged. The results, together with the results of the control experiment, are shown in Table 13 below;

Table 13

Quantity of preservative and clay used Background radiation (%) initial After 10 days was not (control) 95.2 94.3 Nadavin FP (10%) 96.3 95.8 Nadavin LT (10% 95.9 94.9 Kymene 709 (10%) 95.9 95.1 Kymene 557 (15%) 95.9 95.2 Kymene 557 (5%) + Zonyl RP (0.5%) 95.7 94.9 Glanzol CFD (10%) 96.1 95.3 Kymene 557 (3%) + Glanzol CFD (3%) + Zonyl RP (0.3%) 95.9 95.4 Nopcobond SWS 10 (10%) 95.8 95.2

Each coated sheet is placed underneath an ordinary sheet of paper and written on it. Each coated sheet has a clear blue copy of the writing.

Example 14

In the present embodiment, the capsules prepared according to German Patent No. 2,529,427 were used.

22.5 g of Silton M-AB clay, 7.5 g of Dinkie 'A' kaolin, a preservative and 40 g of water are mixed and the pH of the mixture is adjusted to 10 with sodium hydroxide solution. 50 g approx. A 40% solids capsule suspension was added followed by 22.5 g Keestar 328 wheat starch and 15 g Dow 620 latex. The mixture is applied to a paper weight of 49 g / m ^{2 at} 10 g / m ² and dried at 105 ° C for 20 seconds. The results are shown in Table 14 below, together with the results of the control. In the latter case no protective agent is used at all.

Table 14

Quantity of preservative and clay used Background radiation (%) initial After 10 days was not (control) 76.4 64.3 Nadavin FP (10) 90.0 85.9 Poiymin P (10%) 84.8 81.8 Zonyl RP (10%) 85.7 79.5 Glanzol CFD (10%) 85.7 79.9 Sodium lauryl sulfate (10%) 87.0 72.3 Teepol 610 (10%) 86.4 78.0 Teepol GD 53 (10%) 85.8 73.0

Teepol 610 is an anionic surfactant sold by Shell, which is a sodium salt of a secondary alkyl sulfate. Anionic surfactant from Teepol GD 53 and Shell, a mixture of sodium alkylbenzene sulfonate, sodium alcohol sulfate and a nonionic alcohol ethoxylate.

Each coated sheet is placed underneath a plain sheet of paper and written on it. The coated sheets always produce a clear blue copy of the writing.

Example 15

The procedure of Example 14 is followed except that all. 65 ml of the capsule suspension prepared in the same manner as in Example 14 is used instead of the capsule suspension of Example 14. The results are shown in Table 15.

Table 15

Quantity of preservative and clay used Background radiation (%) initial After 10 days was not (control) 94.9 94.3 Nadavin FP (10%) 95.4 95.0 Glanzol CFD (10%) 96.1 95.6 Teepol 610 (10%) 96.2 95.5 Tergitol 7 (10%) 96.5 95.8

Tergitol 7 is an anionic surfactant product from BDH Chemicals Limited, a sodium salt of a C 17 secondary alcohol.

Each of the coated sheets is placed underneath a plain sheet of paper and overlaid on the latter. Each coated sheet produces a clear blue copy of the writing.

Example 16

This embodiment illustrates the application of a coating material of the present invention using an industrial-sized knife coating apparatus. The capsules were prepared as described in Example 11, but the amounts of material used were higher and the mixture was cooled to 15 ° C overnight at 55 ° C.

22.5 kg of Nadavin FP and 296 liters of water were added to the mixer and 225 kg of Silton M-AB was dispersed9

-9181996 We're in the mix. The pH was adjusted to 8 with 13.7 g of 47% sodium hydroxide solution. Then, 500 kg (139 kg dry weight) of capsule suspension was added, 225 kg Keestar 328 wheat starch and 75 kg Dinkie Clay A were dispersed in the mixture and finally 150 kg Dow 620 latex binder (75 kg dry weight) was added. Apply the mixture to a paper weight of 47 g / m ² at 14 g / m ² . The background radiation of the coated sheet was 96.1% after coating, 96.0% after 10 days, and 94.5% after 7 months.

When you place a regular sheet of paper on the coated sheet of paper and write on it with normal pressure, the coated sheet of paper produces a clear blue copy of the writing.

Example 17

This embodiment illustrates the practice of the method of the invention with transfer-type capsules (instead of using "self-supporting" type capsules).

As mentioned above, the use of transfer type capsules generally does not result in an acceptable white copy paper. However, the present embodiment demonstrates that the process results in a product that is more resistant to premature color formation, regardless of the thickness of the capsules.

The capsules used were generally prepared as described in Example 1 (British Patent 1,053,935), except that carboxymethylcellulose was used instead of gum arabic. The capsule suspension was divided into three sections a), b) cs c).

a) -series

The capsule suspension was treated with a 13% solution of BC 71 melamine-formaldehyde pre-condensate as a preservative for ₂ hours at 60 ° C and allowed to cool.

Silton M-AB clay was dispersed in water to give a 40% solids dispersion and the pH was adjusted to 10 with sodium silicate.

100 ml of capsule suspension was then added with stirring and the resulting mixture was spread on a sheet of paper. A dark blue sheet was obtained with a reflection of 19%.

b) -batch

The capsule suspension was treated as described for batch aj.

Then, 40 g of Silton M-AB clay was dispersed in water to form a 40% solids dispersion. Then, 4 g of BC 71 melamine-formaldehyde pre-condensate was added as a preservative and the mixture was heated to reflux and allowed to cool. The pH was then adjusted to 10 with sodium silicate.

100 ml of capsule suspension was added with stirring and the resulting mixture was spread on 5 sheets of paper as described above. Again, the sheet was blue with a 30% reflectance, significantly higher than the 19% reflectance of untreated clay.

c) -batch

In this case, the capsule suspension has not been treated before.

g of Nadavin FP resin as a protective agent was dissolved in 60 g of water. In this solution, 40 g of Silton M-AB clay was dispersed so that ca. A dispersion containing 40% solids was formed. The pH was slowly adjusted with stirring with sodium hydroxide solution.

Subsequently, 100 ml of capsule suspension was added with stirring and the resulting mixture was applied to a sheet of paper as described above. The sheet of paper turned blue again with a reflection of 30%. This is also significantly higher than the 19% reflectance of the untreated clay mixture.

A patent claim

Claims (1)

A patent claim A process for making a self-supporting, pressure-sensitive copying material by coating a material comprising a sheet containing a micro35 capsule comprising a mineral color developer material and a colorless colorant solution capable of reacting with the color developer material, characterized in that the material comprises: Particles and optionally a suspension of microcapsules are treated, prior to use, with one or more protective agents compatible with the microcapsules, such that 5 to 10% by weight of the substance (s) to be treated with an aminoplast polymer such as urea formaldehyde, melamine. formaldehyde or methylated melamine-formaldehyde polymer or epichlorohydrin polymer such as aminoepichlorohydrin polymer45 or amide / aminoepichlorohydrin copolymer or an anionic surfactant such as ethylenediaminetetraacetic acid with a lethal substance or a surfactant containing a sulfate group, preferably with a lauryl sulfate salt or a sulfonate group 50 surfactants, preferably surfactants containing sulfonated ricinoleic acid derivatives and / or dodecylbenzene sulfonate salts or sulfobuccinic acid dibutyl or dioctyl esters, or fluorinated paper finishing agents, or polyethyleneimine The resin is mixed with resins and, when aminoplast polymers are used, the mixture is stirred at elevated temperature, preferably between 50 ° C and 100 ° C. Responsible for publishing ^: Á Director of Economics and Law Publishing Company 86.5592.66-4 Alföld.Nyomda, Debrecen Chief Executive Officer: István Benkő Chief Executive Officer