JPS61230982A - Space holder for copying paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to microcapsules for copying paper.

In simple cases, carbon-free copying systems consist of an upper leaf (
CB leaf). The paper leaf above it has a coloring layer on its surface (CF leaf).

When copying, the microcapsules are ruptured at the text, and the solution containing the color former flows out and is carried onto the underlying color former layer, where the color former develops color.
This results in a copy. When multiple copies are to be obtained, paper sheets (CFB sheets) having a coloring agent on the front side and microcapsules containing color formers on the back side are inserted between these schemes. Self-made paper contains pigment-containing capsules and a coloring agent in a layer on the front side of the paper sheet. When this pigment-containing capsule is ruptured, a color or copy develops in the same layer.

When producing carbon-free copying paper containing color formers encapsulated in microcapsules, individual microcapsules are separated from the coating layer (coating layer) when depositing the microcapsules on the carrier surface. Standing out is the problem. Possible causes include, for example, individual microcapsules being too large in diameter, microcapsules agglomerating into aggregates that are too large, or (due to the uneven microstructure of the paper surface) protruding from the surface. An example of this is that the capsule adheres to the fiber pieces.

When this paper is deposited, the protruding capsules rupture and the dye former solution escapes when inserted into a set of form sheets (for example, when the paper is rolled or bent) or when locally stacked. In this case, coloring occurs on the existing color forming agent layer and stains the surface of the copy, which may make the copy difficult to read. In other words, it is sensitive to the friction of this paper. Therefore, spacing bodies are added to paints containing microcapsules. Since the spacer has a diameter of 1.5 to several times the capsule diameter, it protrudes from the capsule coating and its rigidity prevents unwanted breakage of the capsule. However, the known spacer has the disadvantage that it also protects adjacent capsules from destruction when copying with a pencil or ballpoint pen or by typing on a typewriter.

It is known that increasing the amount of spacer makes the copy more difficult to read and reduces strength. For this reason, it has recently become necessary to make a compromise between the friction sensitivity of the layer containing the dye former in microencapsulated form and the good copying or copying strength.

The first spacers used were short cellulose fibers, also called cellulose fiber waste. This clearly reduces the abrasion sensitivity of the layers containing encapsulated pigment formers, both in CB leaves and in so-called intermediate papers (self-contained papers).

The coating material containing microcapsules and cellulose fibers is applied to paper as a water-based paint using an air brush in a paper coating device and dried. The disadvantage of this coating method is that the coating speed is slow. For higher speeds roll applicators, roll scrapers and smoothing tools are required. In this case, the cellulose fibers, for example, form a felting before being applied to the smoothing tool, so that a uniform coating of the paper is not possible. At the same time, cellulose waste builds up in the coating color reservoir. For this reason, other materials for use as spacing bodies were desired.

German Patent Application No. 1915504 describes the use of starch or starch derivatives having a size of 1.5 to 2 times the size of the microcapsules as spacers.

According to WO 2525901, starch particles from various peas with a size of 20 to 75 μm are suitable as spacers. According to DE 870,837, it is known to use water-soluble, preferably soybean protein particles in amounts of 10 to 50% by weight, based on the microcapsules.

EP 3599 describes the use of polyolefin powders, optionally together with starch particles, as spacers for layers containing microencapsulated dye formers. According to US Pat. No. 4,211,437, it is known to use gelatin-coated kaolin particles with a diameter of 2 to 12 times the diameter of the pigment-containing microcapsules as spacers. US Pat. No. 4,280,718 states that the diameter is 14 to 20 μm.
Grain starch particles crosslinked with m urea-formaldehyde are described as spacers.

According to US Pat. No. 4,327,148, the softening point is 7.
Use of polyolefins above 0° C., such as polyethylene, polypropylene or polystyrene, as well as copolymers thereof or mixtures thereof with a softening point of at least 70° C., in the form of an aqueous dispersion with a particle size of 5 to 60 μm, as spacers It is known to do. Japanese Patent Publication No. 58-9259
According to No. 1, the particle size is 1.5 that of microcapsules.
Compounds containing amylose that are ~10 times more suitable as spacing agents.

All these similar spherical particles are hard. Using these as spacing members does not provide the improved skin to copy density ratio that is obtained when cellulose fibers are used. The reason for this is that the bonding of the particles to the paper is inadequate due to their spherical form, so that friction causes them to peel off from the coating layer and break the capsules when bent.

According to German Patent Application No. 1955542, large microcapsules (3-5μ
m) is mixed with small microcapsules (0.5-2.5 μm) containing the dye former solution in a ratio of 5=1 and deposited on the paper. The larger capsule, containing only solvent, protects the smaller capsule from previous intended destruction. If only the larger capsule with liquid contents is ruptured, no coloration occurs.

If all the intended capsules are destroyed, the dye former will migrate and good color development will occur on the CF layer. However, this system has the drawback that pressures that are too low to break large capsules are actually more than sufficient to break dye-containing capsules. Furthermore, the intermediate lobe or CF
The additional solvent in the B leaf diffuses from the underside of the paper to the surface, entraining the pigment formers and darkening the copy;
Make the recording lines so wide that they are unreadable. The latter paper leaf (
The density of the copy of CF leaf) is CF for this combination.
It is lower than that of B leaf.

The object of the present invention was to develop a spacer which can be used as a spacing body and which does not have the properties which are the disadvantages of conventional spacers.

This problem was solved by the present invention, which uses microcapsules as spacing bodies which contain a hydrophobic substance that is solid at room temperature as core grains.

Accordingly, the present invention provides for approximately 40
Microcapsules containing a hydrophobic substance that is solid at room temperature with a melting point of ~150°C.

The microcapsules of the present invention can be used in the form of an aqueous dispersion or directly in the form of a powder.

The microcapsules of the invention can be mixed with a dispersion of microcapsules containing a dye former, resulting in a homogeneous dispersion with virtually unchanged rheological properties. The microcapsules of the invention, when combined with chromogen-containing microcapsules, provide distinct to significantly higher color densities. That is, compared to the use of microcapsules containing the same amount of dye former together with state-of-the-art spacers, the microcapsules of the invention, also referred to below as spacer capsules, are encapsulated in It can be produced by any known encapsulation method as long as the operation is carried out at a temperature above the melting point of the hydrophobic core material to be used. Examples are: Gelatin-coacervation, interfacial polycondensation to polyesters or polyamides, interfacial polyaddition to polyureas or polyurethanes, precipitation of polymer films by precipitation from polymer solutions, or alone using formaldehyde of urea and/or melamine. Condensation or co-condensation. Encapsulation of prewire hardware by polycondensation of melamine with formaldehyde or based on melamine-formaldehyde is preferred. In order to stabilize the capsule dispersion produced in this case, suitable water-soluble polymers such as polyvinyl alcohol, salts of polyacrylic acid, polymerizable di- or polycarboxylic acids and vinyl isobutyl ether, ethylene and/or acrylic acid ( Alternatively, a copolymer with methacrylic acid) ester, a cellulose derivative, or a polymer or copolymer of a monomer having a sulfonic acid group can be used. In addition, low-molecular surfactant substances can also be used to stabilize the produced capsule dispersion.

In some cases, one can make do without these water-soluble stabilizers.

The solid hydrophobic substance encapsulated in the capsule contains approximately 40
Those having a melting point of ~150°C, especially 50~85°C are used. The hydrophobic material has a penetrometer index value of 0.5 to 200, preferably 1 to 120. As solid hydrophobic substances, use is made in particular of waxes or wax-like substances, examples of which are vegetable waxes containing almost no polymeric fatty acids, such as candelilla wax or carnauba wax; hydrocarbon waxes such as paraffin, osichelite or microcrystalline waxes. Wax: Polymeric fatty alcohols such as octadecanol or ester waxes (free of higher carboxylic acids). Wax-like polymers such as polyethylene wax or preferably polyvinyl ether wax are also used as core material for the microcapsules of the invention. Wax-like substances can be used alone or in mixtures.

Mixtures containing low melting point substances can also be used. Such mixtures allow the melting point and penetrometer index, ie the hardness of the waxy filling, to vary. For reasons of application technology, it is preferred that the hydrophobic substance is colorless or only slightly colored.

The plasticity of wax is simply DGIi'-M at 20℃.
-m3 (standard of the German Oil and Fat Association) as a penetrometer index. It is 0.5-200 preferably 1-
It is 120. This value is the depth that the needle penetrates in 5 seconds.
/10 It is expressed in units of m. This value is AS
This value is the same as that obtained by the needle penetration method of TM-D-1321-61T.

However, other methods can be used to characterize waxes.
It gives other numerical values, e.g. i-HaDGF-
This is Bepplar hardness measured at 20'C using M-11,3K.

The capsules obtained by the above method are of equal size and spherical. Due to its shape, it is suitable for trouble-free processing, for example in high-speed paper coating machines with gloss doctors.

By manufacturing the capsules above the melting point of the core material, the wax undergoes significant volumetric contraction upon cooling and crystallization. This is not compensated for by the crosslinking of the capsule envelope and the thermal diffusion constant which is thereby largely reduced. This is particularly true in capsule walls made of melamine-formaldehyde condensates. A depression is thus created in the spherical surface of the capsule.

In capsules with walls based on melamine-formaldehyde condensates, there are often one or two large depressions. Mesh electron micrographs show that the capsules rest widely on the substrate, often with depressions, which fix the capsules as precisely spherical particles. The capsules can be used either in the form of a suspension obtained during manufacture or in the form of a powder, for example after spray drying or as a sieve fraction, or after centrifugation and drying, for example in a shovel dryer.

The application technical advantage of the wax-containing capsules according to the invention is that, due to the solid, wax-like consistency of their core, the capsules become solid when subjected to slight pressure, such as when stacking papers or when papers are rubbed against each other. and act as a spacing member. This then protects the chromogen-containing microcapsules from destruction.

At higher pressures, such as when writing, the core of the microcapsules of the present invention can move or deform or be crushed and collide with adjacent chromogen-containing capsules. It has been found that although the climbing part of the spacer capsule clearly reduces the friction sensitivity of the layer containing the microencapsulated dye, there is no change in the density of the copy and its good readability. It was done. This applies in particular to small chromogen-containing microcapsules.

It is a decisive advantage compared to state-of-the-art spacing bodies that the use of microcapsules according to the invention as spacing bodies reduces the amount of pigment-containing microcapsules. be able to.

The ratio of spacer capsules to pigment-containing capsules is 0.0! t: may be between 1 and 2:1, preferably between 0.06:1 and 0.9:1. Of course, the size of the spacer capsules compared to the chromogen-containing capsules also plays a role. Generally, as the size of the spacer capsule increases, the frictional sensitivity of the CB layer decreases.

The spacer of the invention works well when the diameter of the spacer capsule is 1.5 to 10 times that of the pigment-containing capsule. That is, the average diameter of the spacer capsule should be between 5 and 50 Ilm, preferably between 6 and 50 Ilm.
35 μm, especially 7 to 30 μm. If it is too thick, it is disadvantageous because the sharpness of the copied image decreases.

By using waxes with low plasticity, friction sensitivity to elevated pressure can be increased. Optionally, the coating colorant may also be mixed with a small amount of the conventionally used hard, non-plastic spacers. In this case, a reduction in the density of the copy must be accepted or compensated for by increasing the amount of capsule containing the dye former.

The composition of the coating color, consisting of the dye former-containing capsules, the binder, the spacer capsules and water, remains essentially unchanged by the employment of the spacer according to the invention. The proportion of each component should be optimized accordingly.

Binders in coating colorants containing microcapsules include:
Conventionally used materials are used; examples include vinyl acetate,
Polymer dispersions based on homopolymers or copolymers of acrylic (or methacrylic) esters, phtadiene, styrene or other ethylenically unsaturated copolymerizable monomers. In addition, water-soluble high polymers can also be used together with the polymer dispersion if necessary.

The optimal binder is easily determined by simple series testing.

Parts and percentages in the examples below relate to weight. The capsule diameter in the examples is not the average (the most frequent diameter determined by microscopic evaluation is shown). The average capsule diameter is the arithmetic mean of both capsule diameters.

A) Test Method Test of Capsule Coatings for Copy Density and Friction Sensitivity A-1, Production of Capsule Coatings a) Coatings containing microcapsules were generally produced as follows.

8.25 parts 40% dye-containing microcapsule dispersion 11.75 parts water 1.30 parts commercially common 50% binder dispersion based on copolymers from styrene and butyl acrylate 1.30 parts Spacing The support (100%) is mixed in a container. A water-containing spacing agent dispersion is added to this so that the water content is 11.75 parts of water.

b) The coating prepared in this manner is applied to the raw material paper for coating by using a wire spiral doctor (distances range from 10 to 60 μm depending on the desired application amount, often 25 μm) onto the raw material paper for coating. lil
/m"≠#, and then heat the paper in the air for 60 minutes.
Dry for a minute or briefly in hot air.

Weigh 100 d each of uncoated paper and coated paper, and determine the coating amount as 97 Crr' from the difference.

A-2, a paper sheet coated with copy density A-1, overlaid on a CF sheet with a coated sheet. Lay two sheets of paper about 40,117 mm on top of it. 4. Paste this set of papers on an electric typewriter.
Write the lowercase letter W in an area of 2 x 6.4 crr1 with a strong impact. The characters are then arranged directly next to each other in one line, each line being arranged one above the other. After leaving it for 60 minutes, the density (ID') of the copy obtained on the fourth sheet is
It is measured as the difference in reflection between the unmarked part (Ryo) and the marked part (Rym) of the CF leaf. Reflection measurements are made using filter Y (
The measurement is carried out using a reflectance photometer equipped with a Zeiss (Ererejo). Indications are in comparison units (%): ID=Ryo-Rym. The reflection of the blank area of the white Cli' leaf is typically 85%.

A-3, Friction sensitivity of capsule-containing coating film Coated paper sheet according to A-1 (shorter length 29 crr
I) is laid on the coated side onto a flat substrate consisting of polished synthetic leather on both sides. A CF leaf with a receptive layer on the underside is overlaid onto the capsule-containing layer. Carefully place one end of a metal disk with a diameter of 50 cm and a thickness of 13 wm on top of the CF leaf. This disc has a felt of the same size and thickness 'ltm pasted on the back side. A cylindrical projection with a diameter of 5 cm projects upward from the center of the disc to a length of 1061EII (the total weight of the disc is 1s7.7jl).

Cover with a metal disc. The weight of each disc is 1000. ! It is i+. This arrangement imposes a pressure of 2.1 N/crn'' on the surface of the paper.

To test the friction sensitivity, one end of the CF leaf was grasped with the hand;
With the weight placed on top, it is slowly and precisely pulled over the capsule-attached paper with the CB layer held tightly to a length of 22 cIIL. Then carefully remove the weight. C.F.
The overlapping surface of the paper is colored more or less intensely depending on the friction sensitivity of the CB line. The color intensity (IR) is measured with a reflectance photometer as in A-2 and is expressed in comparative units (%).

A-4, Adhesion of the layer with microcapsules and spacers The adhesion of the capsule-containing layer is measured as follows.

Gently press the self-adhesive tape against the capsule-covered side with your finger to make it stick, then pull it away again. The turbidity of the self-adhesive tape due to capsules and fibers detached from the layer and deposited thereon is subjectively examined and scored.

Adhesion was good in all laminates cited in the examples and comparable to industrially produced CB leaves, so no particular indication was given in each example.

A-51 Sharpness of Characters The sharpness of copied characters and the associated readability are subjectively examined by comparing them with those of commercially available ordinary copying paper. This was good in all cases and comparable to that with commercial paper.

Sharpness does not deteriorate with increasing amount of spacer. Therefore, no instructions were given regarding this in each example.

B. Examples Example 1 41 externally heated cylindrical stirring vessels with coaxial stirring shafts (with a gear disc with a diameter of 5 cm diagonally carved at the end) In a (Pendrowryk experimental mixer, model LD 50, manufactured by Pendrowryk),
940 g of water and a 20% solution of poly-2-acrylamido-2-methylprono(sulfonic acid/Na salt (viscosity 88
5 mPa5, K value 129) 160. ! mix i',
Gradually add the pH in the form of formic acid (its temperature is slightly higher than the melting point). The rotational speed of the geared disc stirrer is then gradually increased to its final value as the filling height increases.
Increased to 0 rpm. Adjust the pH value to 5°0 if necessary. 1 mol of melamine and 5.2 mol of formaldehyde over 1 hour at 4500 rpm.
Partially methylated precondensate from 5 mol (melamine molecule 1
(contains about 2.3 methoxy groups per piece) 120g
252 g of a clear solution in 132 I of water are added. The temperature was kept at 76°C and the pH number was kept constant at 5.0 by adding 10% formic acid.
Hold at 0. After adding the precondensate, immediately refill the stirrer with a propeller-type stirrer, heat with vigorous stirring (1000 rpm) from 76°C to 80°C over 1 hour, and stir at 80°C for 2 hours. . The dispersion is then adjusted to pH 8.5 with triethanolamine and cooled. The dispersion is passed through a sieve with a mesh width of 1n, and the residue that does not pass remains on the sieve.

The resulting dispersion is colorless and milky, and when examined microscopically, the individual capsules are mostly 8-18 μm in diameter, with a maximum diameter of 40 μm. The solids content is 41.0% (determined by drying the sample at 105° C. for 2 hours). As the capsule cools and the paraffin crystallizes, the volume shrinks, resulting in deep depressions in the otherwise spherical or slightly uneven surface.

Example 2 Slightly larger capsules are produced by operating as in Example 1, but rotating the disc stirrer at 3700 revolutions per minute instead of 4500 revolutions per minute. A capsule dispersion is obtained which has capsules with a diameter of predominantly 10-25 μm; microscopic examination shows that the individual capsules have a diameter of up to 40 μm.

The solids content of the dispersion is 68.0%. This capsule also has a large circular depression on its spherical surface.

Example 6 Proceed as in Example 1, except that a capsule dispersion with capsules of 18 μm in diameter with a melting point of 52-54° C. and a penetrometer index of 30 is obtained, the diameter of the individual capsules being up to It is 40 μm. Solid content is 43.0%
. This capsule has large depressions on its spherical surface.

Example 4 The procedure is as in Example 6, except that the rotation speed of the disk stirrer is 2500 revolutions per minute. The resulting capsule dispersion has a solids content of 45.2% and the diameter of the individual capsules is primarily 10-45 μm. Its surface is rather rough, with 1-2 deep depressions on the spherical surface (measured on the spherical surface (the diameter of the depressions is 70-80% of the diameter of the sphere).

Example 5 The procedure is as in Example 6, except that the rotation speed of the disk stirrer is 3500 revolutions per minute. After adding the precondensate, the rotation speed of the disk stirrer is reduced to 500 rpm. Next, poly-2-acrylamide-2- used in Example 1
20% solution of methylpropanesulfonic acid/Na salt 81
．． 5 g are added in 2 minutes and a further 120 g of the partially methylated precondensate obtained from Example 1 from melamine and formaldehyde. Then, the stirrer is stopped, the dispersion is placed in a flask equipped with a propeller-type stirrer, and the following treatment is carried out in the same manner as in Example 1.

A capsule dispersion is obtained in which the capsules have twice the amount of wall material and the diameter is mainly 2 to 8 μm. Individual capsules are less than 12 μm in diameter (according to microscopic examination)
, the solids content is 41.4%.

Example 6 The procedure is as in Example 5, except that the rotation speed of the disk stirrer during capsule formation is 5500 revolutions per minute and is increased to 6000 revolutions at the end of the prefeed addition. When adding the second portion of the reserve, the number of revolutions is 2500. A colorless, milky dispersion is obtained, the capsules of which have a diameter of mainly 4 to 12 μm. Individual capsule diameter is 20μm
Below, the solids content is 42.6%.

C-1, Testing of paraffin-containing capsule dispersions obtained according to Examples 1 to 6. Alternatively, a state-of-the-art spacing first surface was processed into a coating material using A-1a, which was then coated onto paper using A-1b.

The coated paper obtained was examined for coating weight, copy density according to A-2, and friction sensitivity according to A-3. The results are summarized in Table 1.

The colorant-containing microcapsule dispersion used was prepared according to Example 1 of EP 26914, except that a mixture of dodecylpenzole and diisopropylpenzole (weight ratio 1:1) was used as a solvent for the colorant. used. The capsule gave a blue copy. The diameter of the capsules was mainly 2-5 μm and the solids content was 40%.

As is known from Table 1, practically the same amount of pigment-forming microcapsules (4.5-4.7 jl/m2>
In this case, the distance maintenance physical strength of the present invention is obviously affected. Diameter from 2 to 8 μm (coating 5) to 10 to 25 μm
m (coating 2), the friction sensitivity IR decreases from 23% to 15%. Copy density (ID) from 47% to 5
This is slightly improved to 1%.

Since the spherical spacer capsules with a diameter of 2 to 8 μm are only slightly larger than the 2 to 5 μm of the dye-containing capsules used, the spacer capsules are susceptible to possible fractures due to friction on uneven paper surfaces. However, it may not always be protected. Comparing the IR values, the diameter is 10~
A 25 μm spacer capsule provides the best protection. This diameter is compared to cellulose waste, which is a commercially available spacer with a width of 5 to 15 μm.

Particularly in special concentrations K with a diameter of 20-30 μm.

are almost the same. A comparison of the density and friction sensitivity of capsule coatings produced using paraffin-containing microcapsules as spacers with those produced using state-of-the-art spacers shows the superiority of the capsules of the invention. It is clear that The copy density ID decreases slightly from 45% or 46% to 51%. The friction sensitivity IR is 15%, significantly lower than the 20% or 26% in other cases.

At the same total coverage, the coverage of microcapsules containing one dye former is reduced to about 276.

The friction sensitivity IR decreases from 60% or 61% to 10% or 8%. The density ID of the copy is then 55% (obtained with only 20% of the chromogen-containing capsules) or 51%
(according to approximately the same amount of chromogen-containing capsules) to 5
It decreases from 0 to 49%. Thus, the paraffin-containing capsules of the present invention not only significantly reduce the abrasion sensitivity of the CB layer, but also ensure virtually identical copy densities with smaller amounts of dye-forming microcapsules.

Due to the consistency of paraffin, the copying load hardly increases and the friction sensitivity of the paper or CB layer clearly decreases.

C-2, the content of halafine-containing microcapsules is CB
Testing of the influence on the properties of the coating film a) Coating materials A-1a and A-1b and paraffin-containing capsules of Example 2 (10-25 μm in diameter)
) in increasing amounts to produce coated papers. The results of measuring copy density and friction sensitivity are summarized in Table 2.

b) In another experiment, a coating material (coating colorant) containing a small amount of paraffin-containing microcapsules as a spacing member was produced, similar to C-2a. In this case the amount of chromogen-containing microcapsules was reduced to equal proportions. The composition of the grass cloth colorant and the test results for copy density and friction sensitivity of papers coated with this coating colorant are summarized in Table 6.

As a pigment-containing microcapsule.

The same material as C-1 was used. As the spacer, microcapsules manufactured according to Example 2 were used.

In all coating colors, 1.60 parts of the binder described in A-1alC was used.

As can be seen from Table 3, although the amount of pigment former-containing microcapsules in the colorant decreased, the friction sensitivity decreased as the amount of spacer capsules of the invention increased.

Copy density changed only slightly.

A comparison of the coated product of Comparative Example 4 and the coated product 2.5 reveals the excellent effect of the spacing member of the present invention on cellulose.

Comparative Example 1 a) Spherical particles of melamine-formaldehyde resin were produced by condensing a melamine-formaldehyde precharge in water. The obtained particles had no melting point due to their hardness, and their penetration could not be measured. That is, the penetrometer index was 0. The diameter of this particle is mainly 1
It was 2 to 20 μm.

In the second experiment, all the small particles from experiment a) were slightly agglomerated.

Using the capsules obtained in both experiments, a capsule paint was produced according to A-1. For comparison.

A capsule coating containing cellulose fibers was produced.Capsules containing a pigment forming substance.

Most used capsules giving a black copy with a diameter of 3-6 μm (manufactured according to Example 6 of EP 26914).

The test results are shown in Table 4. From the friction sensitivity value.

It is known that hard balls worsen friction sensitivity.

However, there is no noticeable change in copy density.

Table 4 Spacing member Total coating amount ID IRU/m
2) (%) (%) Cellulose waste Albocel B600150 8.1 43
17 Melamine resin ball φ: 12-20μm 7.8 47
57 Melamine resin ball φ: 12-20μm 8.5 43
Comparative Example 2 Containing 38 Small Sphere Agglomerates Vaseline (white, DAB, penetrometer index >200) was encapsulated in capsules according to Example 3. The rotation speed of the disc stirrer is 4000 rpm. The solids content of the resulting capsule dispersion is 44.4%. The capsule has no or single depression, and the diameter is mainly 5 to 1.
It was 5 μm.

Example 3.1 Similar to Example 3, paraffin (melting point 52-54 DEG C.) is treated with a disk stirrer at 4000 revolutions per minute, resulting in a dispersion with a solids content of 43.0%. This capsule is 1
It is a sphere with one or two distinct large depressions.

The diameter is mainly 5 to 15 μm.

Capsule dispersions obtained in Comparative Example 2 and Example 6.1 and cellulose fiber waste (Albocel B600/
15) as a spacer.

It was used in the preparation of CB-coating colorants according to A-1° and the resulting paper was tested according to A-2 and A-5. The microcapsule dispersion listed in C-1 was used as the microcapsule containing the pigment forming substance.

The test results for coating amount, copy density and friction sensitivity are summarized in Table 5.

Table 5 Spacing body Total coating amount Copy density Friction sensitivity (
g/m2) ID (%) IR (%) Cellulose waste Albocel B600/15 7.6 45
20 Vaseline-containing spacer capsule 7.4 49 3
1 Paraffin-containing spacer capsule 7.8 50
15 (melting point 52-54 DEG C.) The friction sensitivity values show that the soft pasty petrolatum is not in encapsulated form to protect the 1-chromogen-containing capsules from destruction. Its friction sensitivity (IR) is as high as 31%. In contrast, the IR value of paraffin-containing capsules is 15%. Since both capsules have less resistance to destruction of the pigment former capsule when writing, the copy density is significantly higher than in the case of cellulose waste (49% and 50% versus 45%).

Example 7 The procedure was as in Example 6, except that 35 parts of paraffin (penetrometer index 9) with a melting point of 69-76°C and 66 parts of petrolatum (white, DAB, penetrometer index > 2 (10)) were added. The mixture has a melt index of 52-54°C and a penetrometer index of 1.
00.

The rotation speed of the disc stirrer is 4000 revolutions per minute.

A dispersion is produced with a solids content of 44.6% and a diameter of the spherical capsules being mainly from 5 to 18 μm. Each capsule has one or two distinct depressions.

Cab7al coatings made from A-111 and A-1bK are used at a total coverage of 7.4 fl/m''. The density ID of the copy is 49% and the friction sensitivity IR is 20%. This value is comparable to the value obtained when using cellulose waste as a spacer.

Example 8 Proceed as in Example 7, but at pH 5.0 and 80°C.
The rotational speed of the one-disk stirrer was set to 300 rpm. The flow time of the melamine-formaldehyde precondensate is 30 minutes. Paraffin (melting point 69-7
A mixture of 60 parts (3° C.) and 34 parts petrolatum (white, DAB, penetrometer index >200) is encapsulated in capsules.

This mixture has a melting point of 55-62°C and a penetrometer index of 41. The resulting dispersion had a solids content of 43.0%.
It contains spherical capsules with one or rarely two distinct depressions, the diameter of which is mainly 10-30 μm.

Capsules manufactured by A-1a and A-1b (CB
) The coating weight of the coating layer is 7.4 g/m''. Copy density I
D is 47%, and friction sensitivity IR is 6%.

Example 9 The procedure is as in Example 6, except that instead of paraffin, octadecanol with a melting point of 59 DEG C. and a penetrometer index of 2-3 is used. The melt is encapsulated at 35°C. The disk stirrer speed is 6000 rpm. A capsule dispersion with a solids content of 44.4% is obtained. This spherical capsule has a diameter of 5 to 15 μm and has one or two large depressions on its surface.

Using these capsules, a capsule coating material is produced according to A-1a and A-1k) using the pigment-forming substance-containing microcapsules described in C-1. Total application amount is 7.59
7m2, copy density ID is 4.7%, friction sensitivity IR is 1
It is 6%.

Example 10 The procedure was as in Example 1, except that a relatively hard, colorless, cloudy, microcrystalline hydrocarbon wax (Osikelite G521) was used.
208. Melting point 64-67℃1, penetrometer index 18),
At 80° C. and pH 4,5, addition time of melamine-formaldehyde prefeed 35 min and 600 min of disk stirrer.
Encapsulate with Orpm. Solid content is 46.
A 9% colorless milky dispersion is obtained, which contains mainly spherical capsules with a diameter of 6 to 18 μm. The capsule has one or two distinct deep depressions on its surface.

The coatings produced by A-1a and A-1b have a total weight of Zsy/m2, a blue copy density ID of 49%, and a friction sensitivity IR of 14%.

Example 11 The procedure was as in Example 10, except that brownish, slightly soft, microcrystalline hydrocarbon wax (Osikelite BH
447, melting point 60-70℃, penetrometer index 23), 7
Addition time of melamine-formaldehyde prefeed 60 min and 600 O in a disk stirrer at 5 °C and pH 5,0.
encapsulation at rpm. Solids content is 45.6
% of a slightly yellow, cloudy dispersion is obtained. It contains spherical capsules with a diameter of primarily 8-60 ttm and at least one distinct depression.

The coatings produced by A-1a and A-1b had a total weight of 7.5. ji'/m", and the density ID of the blue copy is 45%.
, the friction sensitivity IR is 10%.

Example 12 The procedure was as in Example 11, except that a relatively soft yellowish microcrystalline hydrocarbon wax (Osikelite G
32115, melting point 66-70°C, penetrometer index 24) is encapsulated. A colorless, cloudy dispersion with a solids content of 46.3% is obtained, which contains mainly spherical capsules with a diameter of from 4 to 24 μm, all with at least one depression.

The coatings produced by A-1a and A-1b have a total weight of 7.6 g/m2, a blue copy density ID of 49%, and a rub sensitivity of 17%.

Example 13 Proceed as in Example 3, but instead of paraffin, colorless polyvinyl ether wax (melting point 45-48
℃, penetrometer index 0-1) is encapsulated in a capsule. The resulting colorless milky dispersion has a solids content of 46.6%. It contains capsules mainly 20-45 μm in diameter.

The maximum diameter is 100 μm. The surface of the spherical capsule is rough and has small depressions.

The CB coatings produced by A-1a and A-1b have a total weight of 7.697 m'', a copy density ID of 49%, and a rub sensitivity IR of 11%.

Example 14 The apparatus of Example 1 is charged with 560.9% of water - to which is added a solution of 50g of pork skin gelatin and 279% of water.

It is added at 60° C. with 970 g of a solution of 25 g of gum arabic in 945 g of water. Adjust the pH to 5.0 with 1a% caustic soda solution.
8 and stir at 3500 rpm with a dispersion disk. Next, 150 g of melted paraffin (melting point 52-54°C, penetrometer index 30) was added per minute, and the rotation speed of the disk stirrer was increased to 500 rpm. Disperse to a particle size of ~30 μm.

The resulting dispersion was transferred to a glass flask equipped with a propeller-type stirrer with a rotational speed of 120 Orpm (the diameter of the propeller was 1/6 of the cross section of the container).
60g is charged).

The pH was then gradually adjusted to 4.0 using 10% formic acid over 40 minutes.
Lower it to 8. During this process, a gelatin coaqueous solution is precipitated which coats the individual paraffin melt particles which can be seen microscopically. Next, 8 I of a 67% formaldehyde aqueous solution was added, and the rotation speed of the one-disc stirrer was adjusted to 180 Orpm.
The dispersion is cooled to 5°C using a water bath. Two hours after the temperature reached +5°C, the pH was adjusted using 10% caustic soda solution.
8.3 during 0.5 hours, the water bath is removed and the dispersion is stirred for a further 2.5 hours.

The dispersion is passed through a 1 mm mesh sieve without appreciable residue. The solids content is 12°0%.

This paraffin-containing capsule has a diameter of 10 to 30 μm.
It has a spherical shape with obvious depressions on its surface.

The CB coatings produced from this capsule by A-1a and A-1b had a total weight of 8.19/cm''.

The copy density ID is 47% and the friction sensitivity IR is 26%.

Example 15 Proceed as in Example 14, except that pork skin gelatin 509
and 29g of pork skin gelatin instead of 25g of gum arabic
0 g and carboxymethylcellulose (Curry Tyloh-t/C1000) 5.29 g. In addition, for dispersion, a disk stirrer, Tokunkel's Toolax 45N, was used.
use. The primary capsules with a diameter of 2-5 .mu.m aggregate at a pH of 5.18 to form oval-shaped aggregates with a diameter of 20-60 .mu.m. After curing, solids content is 10.5
% dispersion is produced.

Using this agglomerated capsule according to A-1a and A-1b, a CB coating with a total coverage of 7.497 m'' is produced.The density ID of the well-readable copy is 47%, and the friction sensitivity is 20.
%.

Example 16 Using the apparatus of Example 1, 1511 g of water and polyacrylic acid/
A 15% solution of Na salt (value 135 according to Feikenscher) 366I is mixed with stirring, heated to 80°C and brought to pH 5°0 using formic acid. Melted paraffin (
Melting point 69-76°C, penetrometer index 9) 458! Distribute i. Then 68.6 g of the precondensate as described in Example 1 from melamine and formaldehyde in 109.4 g of water.
6.977) 178 g of clear solution are introduced at a constant rate over 30 minutes. The pH is kept constant at 5.0, the temperature at 80° C., and the rotation speed at 400 Orpm. Five minutes after the addition, the dispersion is transferred to a flask equipped with an anchor stirrer and sieved at 80°C, leaving a trace of residue. A dilute, colorless, milky dispersion is obtained, the solids content of which is 23.8%. The individual spherical microcapsules have a dimpled surface and a diameter of mainly 12-66 μm.

The CB coating produced as a spacer with this paraffin-containing microcapsule by A-1a and A-1t:+ has a total weight of 7.617 m2. A well readable copy has a density ID of 47% and a friction sensitivity IR of 8%.

Example 17 The procedure was as in Example 16, except that 957I water and 142 g of a solution of polyacrylic acid/Na salt were charged first, to which 800 g of molten paraffin was added, and 252 g of precondensate was added for capsule formation. use. Solid content is 44
．． A 7% dilute liquid dispersion is obtained, which contains spherical, slightly hollow capsules (diameter mainly 6-60 μm).

The CB coatings produced by A-1a and A-1b had a total weight of 7.8 fl/m'' and a copy density ID of 48%.
, the friction sensitivity IR is 10%.

Example 18 Proceed as in Example 17, except that polyacrylic acid/N
Instead of a 15% solution of 142 g of a salt.

A solution of 32 g of a copolymer of vinyl methyl ether and maleic anhydride as Na salt (weight ratio 1:1, value 90 according to the Kukencher method, corresponding to a molecular weight of about 100,000) in 111 g of water is used. The rotation speed of the geared disk stirrer is 5000 rpm.

The viscous dispersion obtained has a solids content of 40.6%. It mainly contains spherical, slightly concave capsules with a diameter of 6 to 24 μm.

The CB coating film manufactured from A-1a and A-1bK has a total coating amount of 7.87/m・2 and a copy density ID of 48.
%, and the friction sensitivity IR is 10%.

Example 19 Proceed as in Example 17, except that polyacrylic acid/N
Replace the solution of a salt with 85 g of water (ie operate without water-soluble high polymer).

The rotational speed of the geared disk stirrer is 600 rpm.

The resulting dispersion is filtered through a 350 μm mesh sieve and has a solids content of 43.1%. It contains slightly rounded spherical capsules with a diameter of mainly 15-45 μm.

The CB coatings produced by A-1a and A71b had a total coverage of 7.3.9/m'' and a copy density ID of 50.
%, and the friction sensitivity IR is 10%.

Example 20 The procedure is as in Example 19, but the pH is adjusted to 4.5 and the precondensate is added over 1 hour at 500 Orpm.

The resulting dispersion has a solids content of 45.1% and contains slightly hollow spherical capsules with a diameter of mainly 6-12 μm.

The CB coatings produced by A-1a and A-1b have a total coverage of 7.511/cm, a well-readable copy density ID of 50%, and a friction sensitivity IR of 19%.

Example 21 The procedure is as in Example 1, but at 80° C. and 500 Orpm on a geared disc stirrer.

A 44.5% dispersion containing capsules with a diameter of 6 to 42 μm is obtained.

Testing the Effect of C-30 Spacing Content on Copy Density and Friction Sensitivity of CB Coatings Coatings were prepared according to A-1a and A-1t). At that time, the following was used as the proportion of the spacer between 0 and 1.9 parts by weight.

a) Cellulose fiber waste (Albocel B 600150
) b) Starch particles (special starch K) C) Paraffin-containing capsules of Example 6 d) Paraffin-containing capsules of Example 4 e) Paraffin-containing capsules of Example 2 f) Paraffin-containing capsules of Example 21 Pigmentation The capsules containing C-1 were those giving a blue copy of C-1.

C containing increasing amounts of spacers and cellulose crumbs, starch particles or paraffin capsules of Example 21.
The results of testing the copy density (ID) and friction sensitivity (IR) of the B coating are listed in Table 6.

As the spacer content increased, the copy density decreased in all cases. This decrease was most significant for starch particles. In the case of cellulose waste and paraffin capsules, the decrease was slight.

Friction sensitivity decreased similarly for all spacing bodies. This reduction was about the same for starch and cellulose waste, but was much greater for paraffin capsules.

Table 7 summarizes the results of investigating the copy density and friction sensitivity of CB coatings using various paraffin-containing capsules as spacers in relation to the amount of spacer.

In this case too, the amount of spacer was increased, so that the density of the copies obtained was slightly reduced.

As the diameter of the spacer increased, the concentration decreased accordingly. Melting point and penetrometer index were not appreciably affected. As the amount of paraffin spacer capsules increased, the friction sensitivity decreased in some areas clearly. The thicker the spacer diameter and the higher the melting point, ie the lower the penetrometer index of the encapsulated paraffin, the more strongly the friction sensitivity decreased.

Despite the spherical shape allowing high flow rates in the paper coating equipment, the use of large amounts of spacers did not reduce copy density very much.

+) Melting point +) Penetration meter index ) Diameter of spacer capsule

Claims (1)

[Scope of Claims] 1. Microcapsules containing a hydrophobic substance having a melting point of about 40 to 150°C and solid at room temperature in a polymeric shell. 2. Microcapsules according to claim 1, characterized in that the hydrophobic substance has a melting point of about 50-85°C. 3. Microcapsules according to claim 1 or 2, characterized in that the average particle size of the microcapsules is 5 to 50 μm, preferably 6 to 35 μm, particularly 7 to 70 μm. 4. The solid hydrophobic substance is a wax or wax-like substance, and this has a molecular weight of 0.5 to 200, preferably 1 to 120 at 20°C.
Microcapsules according to any one of claims 1 to 3, characterized in that they have a penetrometer index value of . 5. A patent characterized in that the shell is a coacervate based on gelatin or a condensation product based on urea-formaldehyde, urea-melamine-formaldehyde or melamine-formaldehyde or a polyamide, polyester, polyurea or polyurethane. Microcapsules according to any one of claims 1 to 4. 6. Claims 1 to 4, characterized in that the outer skin is a melamine-formaldehyde condensation product.
The microcapsule according to any of the above. 7. Microcapsules containing a hydrophobic substance that is solid at room temperature and having a melting point of about 40 to 150°C in a polymeric shell are placed at intervals in a laminated sheet containing a pigment former encapsulated in the microcapsules. How to use it as a holding body. 8. The layer is about 40-150°C in the outer skin made of polymer.
Recording system based on self-contained CF/CB or CFB, characterized in that it contains as a spacer microcapsules containing a hydrophobic substance solid at room temperature with a melting point of . 9. The layer is 0.1-7.0g/m^2, preferably 0.5
Recording system according to claim 8, characterized in that it contains ~5.0 g/m^2 of microcapsules.