Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
  • B41M5/1243—Inert particulate additives, e.g. protective stilt materials

Definitions

• carbon-free copying systems consist of the upper sheet, the back with color-containing micro capsule is coated (CB sheet).
• CB sheet the back with color-containing micro capsule is coated
• CF sheet developer layer
• the colorant-containing solution solution runs out and is transferred to the underlying developer layer wear, in which the color formers to the color and thus to the copy develop.
• the Ent microcapsules containing the color formers on the underside wear (CFB sheet).
• Self-contained papers contain color formers Capsules and developer in one layer on the surface of the sheet. If capsules containing color balance are destroyed when they are copied, the Color or copy in the same coating developed.
• the protruding capsules can break and release the color former solution.
• the latter then gives up on the present Colored developer layer and thus leads to contamination of the upper area of the copy, which lead to the illegibility of the copy can; i.e. the papers are sensitive to rubbing.
• spacer of the microcapsule-containing prank color added The spacers have diameters that are 1.5 to be several times the capsule diameter and therefore from the cap protrude the dash and not because of their strength the capsules against Protect wanted destruction.
• the first technically used spacers were short cellulose fa ser, also called cellulose fiber cut. They give a clear ver reduction in the sensitivity to friction of the encapsulated color former ent holding layer with both CB and so-called two-layer Pa paper (self-contained paper).
• the coating slips containing microcapsules and cellulose fibers were first in the paper coating supplements with the air brush as an aqueous one Spreading paint applied to paper and dried.
• This order ver driving has the disadvantage of a lower brushing speed.
• At high Higher speeds are doctor blades, roller scrapers and smooth scrapers conducive. It was found that the cellulose fibers to emerge of matted masses e.g. in front of the smoothing scraper and therefore one flawless, even coating of the paper is not possible. At the same time, the cellulose cut accumulates in the coating color supply at.
• DE-OS 19 15 504 the use of particles of starch or Starch derivatives are described as spacers, the size of which is 1.5 to Is twice the size of the microcapsules.
• DE-OS 25 25 901 starch granules with grain sizes from 20 to 75 ⁇ m from different types of peas suitable as a spacer.
• EP-A-6599 describes polyolefin powder, optionally together with Starch grains, as spacers for microencapsulated color formers holding layers described.
• US Pat. No. 4,211,437 discloses kaolin coated with gelatin particles that are pin-shaped and whose diameter is 2 to 12 times larger is as the spacer of the microcapsules containing the color formers to use.
• polyolefins such as polyethylene, polypropy len or polystyrene and their copolymers and mixtures with an Er softening point of at least 70 ° C in the form of aqueous dispersions, whose particles have a diameter of 5 to 30 microns as a distance holder can be used.
• particles are made of amylose inclusion compound with diameters of 1.5 to 10 times the microcapsule diameter suitable as a spacer.
• the object of the present invention was to provide particles which che can be used as a spacer and which the nachtei current properties of the spacers of the prior art point.
• microcapsules are used as spacers, at least as the core contain a hydrophobic substance that is solid at room temperature.
• the invention relates to microcapsules in a shell from a polymer at least one hydrophobic solid at room temperature Contain substance with a melting point of about 40 to 150 ° C.
• microcapsules according to the invention can be in the form of an aqueous dis persion or as such in the form of powder.
• microcapsules according to the invention can disperse the color formers containing microcapsules are mixed, with a homogeneous dis persion ent with practically unchanged rheological properties stands.
• the microcapsules according to the invention give in combination with color microcapsules containing a significantly higher to considerably higher Color intensity, i.e. a significantly to considerably higher yield Color as containing color formers using the same amount Microcapsules together with prior art spacers.
• microcapsules according to the invention in the following also as spacers Capsules called, can by all known encapsulation processes be produced, as far as these at temperatures above the enamel point of the encapsulated, hydrophobic core material can be.
• a method e.g. into consideration: the gelatin ko azervation, the interfacial polycondensation to polyesters or polyamides interfacial polyaddition to polyureas or polyurethanes, the deposition of polymer films by precipitation from polymer solutions or the homo- and mixed condensation of urea and / or melamine with form aldehyde.
• Encapsulation by polycondensation of Mel is preferred amine with formaldehyde or pre-condensates based on melamine aldehyde.
• This can be used to stabilize the resulting capsule disks persions the appropriate water soluble polymers e.g. Polyvinyl alcohol hol, salts of polyacrylic acid, copolymers of polymerizable di- or polycarboxylic acids with vinyl isobutyl ether, ethylene and / or (meth) acrylic esters, cellulose derivatives and polymers or copolymers of sulfone monomers bearing acid groups can be used.
• low molecular weight surfactants to stabilize the ent standing capsule dispersion can be used. In some cases you can even without these water-soluble stabilizers.
• solid hydrophobic substances to be encapsulated such come along Melting points of approximately 40-150 ° C., preferably those of 50 to 85 ° C. into consideration.
• the hydrophobic substances have penetrometer index values from 0.5 to 200, preferably from 1 to 120.
• a solid hydrophobic Substances come in particular waxes or wax-like substances costume; e.g. Plant waxes that are largely free of higher molecular weight Fatty acids are like candelilla wax or carnauba wax; Hydrocarbon fabric waxes such as paraffins, ozokerite or microcrystalline waxes; higher molecular fatty alcohols such as octadecanol or ester waxes that are free of higher carboxylic acids.
• waxy polymers e.g. Poly ethylene waxes or preferably polyvinyl ether waxes can be used.
• the waxy substances can be used alone or as a mixture will.
• the hydrophobic sub punch as colorless as possible or only slightly colored.
• the easiest way to determine the plasticity of the waxes is according to the penetrometer index at 20 ° C according to DGF-M-III 3 (norm of the German society for Fat science) determined. It should be between 0.5 to 200, preferably between between 1 and 120.
• the values indicate the penetration depth of a Na del in 5 seconds in 1/10 mm. The values are identical to those obtained according to the ASTM-D-1321-61 T needle penetration method the.
• the capsules obtained by the above methods are isometric or spherical. They are excellent in shape, too on fast-running paper coating lines with e.g. Smoothing scrapers without Complications can be processed. Due to the manufacture of the Capsules above the melting point of the core material suffer the wax when cooling and crystallizing out, a considerable loss of volume.
• the capsule shell Because of its networking and with it mostly reduced coefficient of thermal expansion not compensated.
• The is particularly suitable for the capsule walls made of melamine-formaldehyde Condensate too. There are therefore dents in the spherical surface of the Capsules on.
• For capsules with walls based on melamine Aldehyde condensates are usually only one or two larger ones Dents. Scanning electron micrographs show that the capsules usually lie on the surface with the dent and thus lie wider and are therefore tied more tightly than exactly spherical particles.
• the capsules can be made both in the form of obtained aqueous dispersions as well as in powder form, e.g. after Spray drying or after sieving or centrifuging and drying, e.g. in a paddle dryer.
• the application technology advantage of the wax-containing capsules according to the Er is that the capsules because of their solid, waxy Consistency of the core at low pressures, e.g. at each other storing papers in a stack or rubbing them against each other occur, are firm and act as real spacers. Protect you the microcapsules containing color formers before destruction. At higher pressures, such as occur when writing, the cores of the Microcapsules according to the invention flow or deform or die Capsules can be crushed and thus the destruction of the neighboring capsules containing bearded color formers.
• the spacer ratio capsules for color formers containing capsules can vary from 0.03: 1 to 2: 1 ieren. The ratio is preferably between 0.06: 1 and 0.9: 1.
• the size of the spacer capsules also plays in relation to the Capsule containing color formers a role.
• the spacer capsules increase the sensitivity to friction of the CB layer.
• the spacer capsules according to the invention work well if they are 1.5 to 10 times the diameter of the color former containing microcapsules, i.e., the spacer capsules should average diameters of 5 to 50 microns, preferably those with 6 up to 35 microns and especially those from 7 to 30 microns. Too big Spacer capsules are disadvantageous because they limit the sharpness of the through can reduce the typeface.
• the rubbing can insensitivity to increasing pressure can be increased.
• the coating color can also be used in certain quantities Add hard, non-plastic spacers. In this case one has to accept a decrease in the intensity of the copy or by a larger proportion of the capsules containing the color former compensate.
• composition of the coating colors from Kapfer containing color formers The binders, binders, spacer capsules and water stand capsule of the present invention is not significantly changed. The proportions of the components must be optimized if necessary.
• the coating colors containing the microcapsules are the Suitable previously used: e.g. Polymer dispersions based on Homo- and copolymers of vinyl acetate, (meth) acrylic esters, butadiene, Styrene and other ethylenically unsaturated, copolymerizable mono meren; water-soluble high polymers can also be used, ge if necessary together with polymer dispersions.
• the optimal binder can easily be determined by simple series tests.
• the mean capsule diameter is the arithmetic mean of the two specified capsule diameter.
• the sheet coated according to A.1) is placed with the coated side on a CF sheet. 2 layers of paper of approx. 40 g / m2 are placed on top. This stack is clamped in an electric typewriter and with the greatest stroke strength a field of 4.2 x 3.4 cm is written with the letter small w, the letters being lined up directly in the line and the lines being arranged one above the other. After 30 minutes of storage, the intensity (ID) of the copy obtained on the fourth sheet is determined as the difference in the reflection of the unwritten (R yo ) and the described (R ym ) CF sheet. The reflection was measured in a reflection photometer with the filter Y (Elrepho®, from Zeiss).
• the reflection of the blank white CF sheet is generally 85%.
• the sheet coated according to A.1) - minimum length: 29 cm - is with the coated side up on a flat surface from a synthetic leather sanded on both sides. Then a CF Sheet with the slave layer facing down, towards the capsule-bearing layer placed. A metal is carefully placed on one end of the CF sheet disc 50 mm in diameter and 8 mm thick. The disc bears an equal-sized, 2 mm thick felt on the lower side lay. A 106 mm long cylinder protrudes from the center of the disc 5 mm diameter mandrel (total weight of the disc 137.7 g). Over the mandrel are 4 metal discs, one in the middle Have a 6 mm ⁇ hole. Weight per slice: 1000 g. The An order loads the paper surface with a pressure of 2.1 N / cm2.
• the CF sheet is now attached to the end for the friction sensitivity test grabs and by hand together with the weight on it slowly exactly 22 cm over the held capsule-bearing paper with the CB layer drawn. The weight is carefully removed. Under the The contact surface is the CF paper depending on the friction sensitivity of the CB lines more or less discolored. The intensity (IR) of the Discoloration is measured with the reflection photometer as in A.2) and given in relative units (%).
• a self-adhesive tape was applied to the with light finger pressure Capsules coated side stapled and immediately removed again.
• the Turbidity of the self-adhesive tape due to torn out of the layer capsules and fibers attached to it were subjectively rated according to notes Right:
• paraffin melting point 69 to 73 ° C, Penetrometer index 9
• the speed of the Toothed disk stirrer with increasing filling level slowly to the final value raised from 4500 rpm.
• At 4500 rpm then within one Hour 252 g of a clear solution from 120 g of a partially methylated ten precondensates (contains about 2.3 CH3O groups per melamine molecule) from 1 mol of melamine and 5.25 mol of formaldehyde in 132 g of water.
• the dispersion is immediately mixed with a stirrer Propeller stirrer decanted and from 76 ° C in 1 hour with intensive Stirring (1000 rpm) heated to 80 ° C and stirred at 80 ° C for 2 hours.
• the dispersion is passed through a sieve with a mesh size of 1 mm sieved, with a negligible residue on the sieve ver remains.
• the dispersion obtained is colorless, milky and contains microscopic assessment of individual capsules from predominantly 8 to 18 ⁇ m in diameter, individual capsules have a maximum diameter 40 ⁇ m.
• the solids content is 41.0% (determined by 2 hours Drying a sample 105 ° C).
• the capsules have as a result of the volu human shrinkage when cooling and crystallizing the paraffin almost all a deep indentation or dent in the otherwise spherical and somewhat fine-grained surface.
• Example 2 The procedure is exactly as in Example 1, but the speed is of the disk stirrer set to 3700 instead of 4500 rpm so that larger capsules are formed.
• a capsule dispersion is obtained with capsules of one of the most common Diameters from 10 to 25 ⁇ m. Individual capsules have a through knife up to a maximum of 40 ⁇ m after microscopic measurement. The Fixed content of the dispersion is 38.0%. These capsules also have a large round dent on its spherical surface.
• a capsule dispersion is obtained, the capsules of which are common most diameters from 8 to 18 microns. Have individual capsules a diameter of up to a maximum of 40 ⁇ m. Solids content: 43.0%. The capsules have a larger dent in their spherical top area.
• Example 3 The procedure was as in Example 3, but with the disc stirrer set to 2500 rpm.
• the resulting capsule dispersion has one Solids content of 45.2%.
• the spherical capsules have one common most diameters from 10 to 45 ⁇ m. Your surface is very light roughened and has 1 to 2 deep dents in the spherical surface (Diameter of the dent 70 to 80% of the ball diameter, measured on the surface of the sphere).
• Example 1 The procedure was as in Example 3, but with the disc stirrer set to 6500 rpm. After adding the precondensate, the Rotational speed of the disc stirrer to 5000 rpm low. Then 81.5 g of that in Example 1 were used in 2 minutes det 20% solution of poly-2-acrylamido-2-methylpropanesulfon acid / sodium salt added and then 252 g of the clear solution containing 120 g of the partially methylated specified in Example 1 Pre-condensates from melamine and formaldehyde. Then the stirrer turned off the dispersion in the equipped with propeller stirrer Given the flask and worked up as in Example 1.
• a capsule dispersion was obtained, the capsules of which were double Contain a lot of wall material and the most common diameter of Have 2 to 8 microns. Individual capsules have a diameter of up to 12 ⁇ m (according to microscopic assessment). Solids content: 41.4%.
• Example 5 The procedure was as in Example 5, but the speed was Disc stirrer during capsule formation 5500 rpm. Towards the end of the expand of the pre-condensate was raised to 6000 rpm.
• Microcapsule dispersion containing the color former specified below was made without the spacer and the spacer capsules from Bei games 1 to 6 and ge with spacers of the prior art processed according to A1.a) into coating compositions and according to A1.b) Paper applied.
• the application weight was on the coated papers obtained and according to A2) the intensity of the copy and according to A3) the friction sensitivity determined.
• microcapsule dispersion containing color formers used was prepared according to EP-B-26 914, Example 1, but a mixture of dodecylbenzene and diisopropylbenzene in a weight ratio of 1: 1 was used as the solvent for the color formers.
• the capsule has blue copies. The most common diameter of the capsule is 2 to 5 ⁇ m. Solids content: 40%.
• the spherical spacers with diameters from 2 to 8 ⁇ m are only slightly larger than the cap containing color formers used seln with 2 to 5 microns in diameter, so that the spacer capsules the latter does not always exist on the uneven paper surface protect against possible destruction when rubbing.
• the comparison of the IR values indicate that spacer capsules are 10 to 25 ⁇ m in diameter show the best protection. This diameter comes up to the dimensions of the commercially available spacer cellulose cut with 5 to 15 ⁇ m Width and 20 to 60 ⁇ m length, but especially the special thickness K with 20 up to 30 ⁇ m in diameter quite close.
• Microcapsules containing color formers were the same as in C.I. used.
• Microcapsules produced according to Example 2 were used as spacers used.
• Capsule lines made.
• a capsule line was used Cellulose cut fiber made.
• Containing color formers Capsule here was a black copy-providing capsule a common diameter of 3 to 6 ⁇ m used (manufactured according to EP-B-26 914, example 6).
• Vaseline (white, DAB, penetrometer index> 200) is according to the information of the Example 3 encapsulated.
• the rotational speed of the disc stirrer was 4000 rpm.
• the resulting capsule dispersion has a solid matter stop of 44.4%.
• the capsules are spherical with occasional one Indentation. The most common diameter was 5 to 15 ⁇ m.
• Example 3 If you work according to Example 3 with paraffin (melting point 52 to 54 ° C) 4000 rpm of the disc stirrer, so you get a dispersion with a Solids content of 43.0%.
• the capsules are spherical with one or two very clear, large indentations. The most common diameter is 5 up to 15 ⁇ m.
• the capsule disper obtained according to Comparative Example 2 and Example 3.1 Sions and cellulose fiber cut (Arbocel B 600/15) were used as the distance holder for the production of CB coating colors according to A.1) and the papers obtained according to A.2) and A.3) checked. Included as a color former en Microcapsules became the microcapsule dispersion given under C.I. used.
• Example 3 The procedure is as in Example 3, but a mixture of 35 parts paraffin with melting point 69 to 73 ° C (penetrometer index: 9) and 66 parts of petroleum jelly (white, DAB, penetrometer index> 200) were used.
• the Mixture has a melt index of 52 to 54 ° C and a penetrometer index of 100th rotation speed of the disc stirrer: 4000 rpm.
• the capsule coating produced according to A1.a) and A1.b) has a total carrying weight of 7.4 g / m2.
• the values correspond those that are obtained with cellulose cut as spacers.
• the feed time of the melamine-formaldehyde precondensate was 30 minutes.
• a mixture of 60 parts paraffin was encapsulated (Melting point 69 to 73 ° C) and 34 parts of petroleum jelly (white, DAB, Penetro meter index> 200).
• the mixture has a melting point of 55 to 62 ° C and a penetrometer index of 41.
• the resulting dispersion had one Solids content of 43.0% and contains spherical capsules with 1, rarely 2 clear dents with a common diameter of 10 to 30 ⁇ m.
• the capsule (CB) line produced according to A1.a) and A1.b) has an order weight of 7.4 g / m3.
• Example 3 The procedure is as in Example 3, but instead of paraffin octa decanol with a melting point of 59 ° C and a penetrometer index of 2 used to 3. So that a melt is present, it was encapsulated at 65 ° C. The disc stirrer runs at 3000 rpm. It became a capsule disperison with obtained a solids content of 44.4%. The spherical capsules have a diameter of 5 to ⁇ m and carry 1 to 2 larger dents in their surface.
• the capsules carry 1 to 2 distinct, deep Dents in their surface.
• the high-speed stirrer turned at 6000 rpm.
• the spherical capsules had one of the most common Diameters from 8 to 30 ⁇ m and at least one significant dent.
• Example 11 The procedure was as in Example 11, but a relatively soft, yellowish microcrystalline hydrocarbon wax (ozokerite GS 2115) (Melting point 66 to 70 ° C, penetrometer index 24) encapsulated.
• ozokerite GS 2115 a relatively soft, yellowish microcrystalline hydrocarbon wax (ozokerite GS 2115) (Melting point 66 to 70 ° C, penetrometer index 24) encapsulated.
• the colorless, cloudy dispersion has a solids content of 46.3%.
• the spherical capsules have a common diameter between 4 and 24 ⁇ m and all have at least one indentation.
• Example 3 The procedure is as in Example 3, but instead of the paraffin colorless polyvinyl ether wax (M.G. melting point 45 to 48 ° C; Penetro Encapsulated meter index from 0 to 1).
• the disc stirrer also rotates 5000 rpm.
• the resulting colorless, milky dispersion has a solids content of 43.6%.
• the capsules contained therein are the most common Diameters from 20 to 45 ⁇ m, individual capsules to such a size 100 ⁇ m.
• the surface of the spherical capsules is rough and shows one small dent.
• a propeller stirrer Propeller diameter 1/3 of the tank cross section
• the dispersion is then passed through a sieve with a mesh size of 1 mm sieved significant residue.
• the solids content is 12.0%.
• the paraffin-containing capsules are spherical with clearly indented ones Surface and show a diameter of 10 to 30 microns.
• Example 14 The procedure is as in Example 14, but instead of 50 g Pig skin gelatin and 25 g gum arabic 29.0 g pig skin gelatin and 3.2 g of a carboxymethyl cellulose (Tylose C 1000 from Kalle) ver turns. Instead of the disc stirrer, a Turrax 45 N is used Jahnke & Kunkel with a speed of 8000 rpm for dispersion used. Agglomerate the primary capsules with a diameter of 2 to 5 ⁇ m when setting the pH to 5.18 to spherical to ellipsoid Agglomerates from 20 to 60 ⁇ m in diameter. After hardening arises a dispersion with a solids content of 10.5%.
• K value after Fikentscher: 165 a polyacrylic acid / sodium salt
• the thin liquid colorless, milky dispersion has a solids content of 23.8%.
• the spherical, individual microcapsules show dents in the upper surface and have a common diameter between 12 and 36 ⁇ m.
• Example 16 is repeated with the following change: 957 g of water and 142 g of the solution of the polyacrylic acid / sodium salt are introduced, then 800 g of melted paraffin are introduced and encapsulated 252 g of the pre-condensate solution used. It became a thin liquid persion with a solids content of 44.7% and spherical, slightly absorbed dent capsules (most common diameter: 6 to 30 ⁇ m).
• Example 17 is repeated, but instead of the solution from 142 g Polyacrylic acid / sodium salt (15%) a solution of 32 g of a copoly merisates from vinyl methyl ether and maleic anhydride (1: 1 weight parts; K value according to Fikentscher: 90, corresponding to a molecular weight of approx. 100,000) used as the sodium salt in 111 g of water.
• the tooth lock washers stirrer has a rotation speed of 5000 rpm.
• the slightly viscous dispersion obtained has a solids content of 40.3%. It contains spherical, slightly dented capsules with one most common diameters from 6 to 24 ⁇ m.
• Example 17 The procedure is as in Example 17, but the solution of the poly acrylic acid / sodium salt replaced by 83 g water (i.e. it is made without any water-soluble high polymers worked).
• the speed of rotation of the toothed disk stirrer is 6000 rpm.
• the dispersion obtained was sieved through a sieve with a mesh size of 350 ⁇ m and had a solid content of 43.1%. It contains spherical capsules with slight dents that have a common diameter of 15 to 45 ⁇ m.
• Example 19 The procedure is as in Example 19, but the pH to 4.5 ge provides and the pre-condensate in the course of an hour at 5000 rpm give.
• the dispersion obtained has a solids content of 45.1% and contains slightly dented spherical capsules with a common diameter of 3 to 12 ⁇ m.
• the CB line produced according to A1.a) and A1.b) has a total line weight of 7.5 g / m2.
• Example 1 is repeated, but at 80 ° C. and 3000 rpm Toothed disk stirrer worked.
• the capsules containing blue color were used as color formers C.I. used.
• Table 6 shows the results of copy intensity (ID) and rub sensitivity (IR) of CB coatings, the increasing amount of distance holder, namely cellulose pulp, starch granules and paraffin capsules from Example 21 included, juxtaposed.
• the sensitivity to friction also decreases with all spacers.
• the decrease in starch and cellulose cut is about the same for those Paraffin capsules, however, are extremely large.
• Table 7 shows the copy intensities and sensitivity to rubbing of CB lines with different capsules containing paraffin as Spacers depending on the amount of spacers in the CB line compiled.

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• Manufacturing Of Micro-Capsules (AREA)
• Color Printing (AREA)

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Citations (5)

• 1985
  • 1985-04-06 DE DE19853512565 patent/DE3512565A1/de not_active Withdrawn
• 1986
  • 1986-03-25 FI FI861265A patent/FI861265A/fi not_active Application Discontinuation
  • 1986-03-29 EP EP86104337A patent/EP0197470A3/de not_active Withdrawn
  • 1986-04-03 BR BR8601503A patent/BR8601503A/pt unknown
  • 1986-04-04 AU AU55661/86A patent/AU5566186A/en not_active Abandoned
  • 1986-04-04 ES ES553746A patent/ES553746A1/es not_active Expired

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