JP2999034B2 - Coater for coating non-carbon pressure-sensitive copy paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-carbon pressure-sensitive copying paper which is excellent in coloring properties, stain resistance and appearance of a coated surface, enables high-speed coating and enables stable production. The present invention relates to a coating device.

[0002]

2. Description of the Related Art A non-carbon pressure-sensitive copying paper usually has a colorless electron-donating dye (hereinafter referred to as a color forming agent) on one side of a support.
Basically, there is a so-called upper sheet coated with a microcapsule containing a solution of the above and a so-called lower sheet coated with an electron-accepting acidic substance (hereinafter referred to as a developer). The coloring agent is released from the microcapsules of the coloring sheet by the writing pressure or the pressure of a typewriter or the like, and comes into contact with the developing agent of the coloring sheet to form a color, and the image is formed. It is obtained.

[0003] Further, a middle sheet having a role of a color former sheet and a developer sheet (a microcapsule coating layer containing a color former is provided on one side of a support, and the other side is provided) By combining a large number of sheets (provided with a developer coating layer) between an upper sheet and a lower sheet, many copies can be made.

A microcapsule containing a color former solution is coated on one surface of a support, and a color developer is further coated thereon or a microcapsule containing a color developer solution is applied. If a single coating is carried out by mixing the agents, a printed color image can be obtained on one sheet, and a self-coloring type sheet is obtained. Hereinafter, the self-coloring type sheet can be basically considered to be the same as the coloring agent sheet.
It will be explained in the following.

In general, the following four items can be cited as quality conditions required for a color-developing agent sheet for a non-carbon pressure-sensitive copying paper and main conditions required during production. High color density, clear image can be obtained in a short time, and there is no deterioration over time. When color formation is not intended, i.e., during the manufacturing process, various printing processes, cutting process, storage or handling in a sheet or rolled state of a color former sheet for non-carbon pressure sensitive copy paper, What does not happen. The coated surface has no streaks or bumps, no uncoated parts, etc., and the appearance is not bad. High-speed, high-concentration coating is possible.

Although the two items have conflicting characteristics, it is difficult to sufficiently satisfy both of them.
The binder can also be improved by devising factors such as the manufacturing conditions of the microcapsules applied to the color former sheet, the type and amount of the protective agent, and the type and amount of the binder.
Improvements have been made in terms of the type and amount of the material and the winding method, and many proposals have been made for them.

On the other hand, in order to obtain high productivity in the production of a color former sheet for non-carbon pressure-sensitive copying paper, the object is to minimize the drying energy during coating and increase the coating speed. The aim is to increase the concentration of the coating liquid. As a means,
Improvements have been made to the liquid properties of the coating solution and the coating method have been devised. Particularly, in the case of a color former sheet, a low-viscosity microcapsule emulsion (for example, JP-A-63-2875)
No. 42) or a method using a low-viscosity binder (for example, JP-A-2-3367).

However, the colorant sheet obtained by the high-concentration coating by the above-mentioned means causes a decrease in stain resistance due to rubbing during actual use, and the colorant sheet for non-carbon pressure-sensitive copying paper. However, the quality of the product was not sufficiently satisfied.

As a method of forming a microcapsule coating layer of a color former sheet, a method using an air knife coater has been conventionally used. In such a method, an excess coating liquid is scraped off with air. The required amount is applied. The main use of air-knife coaters is
It is considered that the coating can be performed at a relatively high speed (300 m / min or more) and that the method has been conventionally used for coated paper for printing and the like. However, in such a method, generation of mist, noise, and the like poses a problem for recent demands for a higher speed (800 m / min or more).
Further, a phenomenon in which a protective agent having a large particle diameter is selectively scraped off by excessive air causes a so-called classification effect. As a result, a large amount of a protective agent having a small particle diameter increases on the support, and the resistance of the colorant sheet is reduced. There was a problem that the contamination was reduced.

In order to solve the above problem, a method using a so-called curtain coater for forming a free-fall vertical curtain (for example, Japanese Patent Publication Nos. 61-46187 and 63-239) has been devised. I have. This method is a coating method which has already been widely used in the field of photosensitive recording materials (for example, JP-B-49-24133 and JP-B-49-3544).
No. 7) is applied to the coating of pressure-sensitive copying paper. It does not require any classification of protective agent and can be applied at a relatively high concentration compared to the air knife coater normally used. This is a method for forming a microcapsule coating layer.

The above-described coating method of the free-fall vertical curtain solves the problem of the air knife or blade coater. However, a head from the upper end of the liquid level in the liquid supply head is used. Since the curtain film is formed by free fall from the height, if the viscosity of the coating solution is increased by increasing the concentration of the coating solution, a desired amount of the solution may not be obtained. Accordingly, in order to obtain a desired amount of liquid, the opening width of the outlet slit of the head is increased to reduce the flow pressure loss, and the length of the outlet slit in the vertical direction is reduced to reduce the flow pressure loss. It is necessary to take any measures such as increasing the height of the liquid supply surface to increase the head difference.

At this time, when the opening width of the outlet slit of the head is increased, the flow velocity at the slit outlet is reduced as compared with the case where the same flow rate is obtained without changing the opening width. Therefore, the collision speed at the contact point between the support and the curtain film is reduced if the height of the curtain film is the same. When the speed at the point of contact between the support and the curtain film is reduced, it becomes difficult to break through the air boundary layer on the surface of the support, and in particular, high-speed coating exceeding 800 m / min becomes impossible.

When the length of the exit slit of the head is shortened, the flow tends to flow out of the slit exit without sufficiently rectifying the turbulence of the flow due to the narrowed flow path shape in the slit. No film is obtained.

Further, when the liquid supply surface is increased, it is necessary to increase the height of the liquid retaining portion of the head. Further, when the amount of staying liquid increases, the staying time of the liquid becomes longer, and the aggregation of the liquid proceeds, which may block the slit portion. The aggregation of the liquid
When the concentration of the solution is increased, the solution becomes more remarkable. In addition, a method of adding a dispersant or an anti-agglomeration agent to prevent aggregation of the liquid is conceivable.

As described above, the free-fall vertical curtain type head cannot cope with a further increase in the concentration of the coating liquid, and the concentration range of the coating liquid has an upper limit, which is extremely narrow. Further, in order to make the profile uniform, the pressure in the head must be as low as possible. For this reason, the head is closed compared to a pressurized curtain coater which forcibly applies pressure to the head as described below. It is easy to do this.

On the other hand, when the solid content concentration of the coating liquid decreases,
Since the viscosity tends to be low, the pressure of the liquid supply head is reduced, and considerable restrictions are imposed on the hard surface in order to form a uniform curtain film. Furthermore, the amount of movement of water and the binder with respect to the capsule during drying is increased, and the water and the binder are apt to be unevenly distributed on the surface of the coating layer, and the distribution of the binder is likely to be uneven on the surface. Color formation is suppressed in the portion where the binder is localized on the surface, and conversely, in the portion where the binder is sparse, color formation tends to be accelerated, and color formation unevenness tends to occur.

In recent years, there has been a demand for high-speed, high-concentration coating exceeding 1000 m / min. According to this method, as the speed increases, the curtain film fluctuates due to the flow of air accompanying the support, and at the same time, the surface of the support increases. The so-called "repelling phenomenon" in which the curtain film cannot break through the boundary layer because the boundary layer of the air becomes too thick, and in the end the coating film is disturbed and the coating liquid is not received on the surface of the support ", Thereby causing a coating unevenness or an uncoated portion.

In order to solve these problems, a method of providing a wind shield plate (for example, Japanese Patent Publication No. Sho 53-31005) and a method of covering the entire portion of a liquid supply head where a curtain film is formed (for example, Japanese Patent Publication No. Sho 57-105) Japanese Patent Application Laid-Open No. 2005-54969) and a method of installing a suction device immediately before a curtain film (for example, Japanese Patent Publication No. 62-186966) have been devised, but no solution has yet been found.

In addition to these methods, generally, the free fall speed of the curtain is increased to increase the collision speed, and the free fall car
Although it can be improved to some extent by giving the ten a momentum that can sufficiently destroy the boundary layer of air, if the flow is too high other than the above-mentioned reason, even if the air flow accompanying the support is relatively small, The effect was limited because the curtain was disturbed by air resistance.

On the other hand, there has been proposed a coating method in which a curtain is formed by forcible pressure in order to make up for the drawbacks of the above-mentioned coating method. That is, a curtain film of a coating liquid containing a microcapsule containing an electron donating dye as a main component is formed from a pressure type liquid supply head having a slit, and the height of the liquid supply head is adjusted to an appropriate height. This can be achieved by providing a coating layer by holding and forcing the support at a certain speed or higher by forced pressure. Here, the forcible pressurization means that a structure other than the liquid supply port and the liquid outflow slit is hermetically closed, and at least several hundreds at the manifold portion in the liquid supply head due to the liquid supply pressure of the pump. When pressurized to g / cm ² or more, it is basically different from the free-fall type curtain described above. That is, in the free-fall type, it is necessary to keep the pressure in the liquid supply head as low as possible in order to make the profile uniform, and it is difficult to remove the obstruction once formed in the slit. On the other hand, in the pressurized type handled by the present invention,
Since sufficient pressure is applied, an obstruction is hardly generated, and even if it is generated, it is needless to say that the obstruction is more easily removed than the free type.

Although these solve the problem of the air-knife coater, any of these methods is
Since the curtain is formed from the slit, there is a problem that the blockage is caused by bubbles, agglomerates, liquid scum, and the like, and there is a high possibility that uneven coating or an uncoated portion is generated. Further, even if no clogging occurs, there is a problem that if the bubbles are not sufficiently removed, a large number of small uncoated portions called several mm-class drip are formed on the coated surface.

[0022]

SUMMARY OF THE INVENTION The present invention relates to a conventional
The object of the present invention is to overcome the problems in quality and production of a color former sheet for carbon pressure-sensitive copying paper. Specifically, a coating apparatus for a color former sheet satisfying all of the following items is provided. To provide. High-density color development can be obtained by writing pressure or pressure from a typewriter or the like. That is, a clear image can be obtained even when copying a large number of sheets. Prevents contamination when color development is not intended. That is, friction stains generated at the time of rubbing, coloring agent sheet storage, printing,
Less pressure stains applied during cutting and excellent stain resistance. There is no unevenness of coating, uncoated portion or dropout, and the appearance of the coated surface is good. High-speed, high-concentration coating is possible, and there is little adverse effect of slit blockage. That is, the drying load can be reduced by the high-concentration coating solution, and high productivity without deterioration in quality can be obtained because of the measures against clogging.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a microcapsule containing an electron donating dye from a pressurized (forced drop type) liquid supply head having a slit. to form a curtain film of the coating solution mainly composed, provided a coating layer made to collide with the support Roh
-In a carbon pressure-sensitive copying paper coating device , the specific gravity of the processing solution must be true specific gravity before the coating solution is supplied to the liquid supply head.
With a vacuum defoamer to make 95% or more of
You. After the coating liquid is processed by the vacuum defoamer, the coating liquid is overflowed before being supplied to the liquid supply head.
A horn-shaped tube is provided which is widened upward, and the coating liquid overflows from the upper part of the tube to remove bubbles . Further, the coating liquid overflows from the manifold in the liquid supply head.
This can be achieved by providing a tube to allow the coating solution to overflow and remove bubbles.

Conventionally, in a curtain coater, as a measure against clogging, an additive such as an antifoaming agent for stabilizing a curtain film, which causes a difference in interfacial tension, cannot be added so much. When the amount of foam is large, the foam is likely to be clogged, and furthermore, there is a high risk of causing a curtain crack. Therefore, the flow rate must be increased more than necessary to stabilize the curtain. However, increasing the flow rate of the curtain inevitably raises the problem that the liquid concentration cannot be increased or the smearing speed must be increased. In addition, when the foam is applied as it is to the coated surface, the portion forms an uncoated portion called "slack", and as a result, the color becomes undeveloped, which significantly lowers the commercial value. Therefore, the present inventor aimed to stabilize the curtain film by minimizing the addition of an antifoaming agent and defoaming by a mechanical method. In particular, the specific gravity of the treatment liquid in a vacuum defoaming machine was 95% of the true specific gravity. % Was found to be effective.

However, in general, the dispersion is liable to agglomerate to some extent. In particular, if there are many bubbles, there is a high possibility that agglomeration with bubbles as nuclei will occur. In addition to the defoaming machine, the coating solution is passed through a horn-shaped tube that spreads upward and the coating liquid is overflowed from the top of the tube.
Allow the foam to flow into the liquid supply head. Furthermore, even if bubbles enter the head, overflow is performed from the manifold in the liquid supply head to prevent the bubbles from being sent to the slit portion, which is effective for blocking, and It was found that since no bubbles were introduced into the curtain, no uncoated portion called "slack" caused by the bubbles was generated. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view of a coating apparatus for coating microcapsules according to an embodiment of the present invention.

The coating liquid 1 containing microcapsules as a main component prepared beforehand is defoamed from the storage tank 2 by a vacuum defoamer 15 so that the specific gravity of the processing liquid becomes 95% or more of the true specific gravity. Before the liquid is supplied to the liquid supply head 4 by the metering pump 3, the liquid is passed through a flared horn-shaped pipe 16, and the coating liquid is overflowed from the upper part of the pipe to the liquid supply head 4. Sent. At this time, the operating conditions of the vacuum defoamer 15 are, specifically, that the degree of vacuum is -600 mmHg / cm ² or less and the rotation speed of the dispersion plate is 1000 rpm or more, so that the specific gravity of the processing liquid is 95% of the true specific gravity. It is possible to do the above. At this time, since the supply amount of the coating liquid is proportional to the coating amount of the final product and the line speed at the time of coating, the control of the supply amount of the coating liquid to the liquid supply head 4 is performed with high accuracy. There is a need to do.
Therefore, a variable flow type non-pulsating constant flow pump is suitable as the fixed amount pump 3.

The inside of the liquid supply head 4 comprises a manifold 5 and a slit 6, each of which is finished with high precision. The supplied coating liquid 1 is filled in the manifold 5 and sent to the slit 6 where the influence of the dynamic pressure due to the supply of the pump is reduced in a narrow gap passing therethrough, and the pressure distribution in the width direction is uniform. Be transformed into Eventually, the coating liquid at the tip of the slit 6 has a more uniform pressure distribution and flow velocity distribution in the width direction and flows out from the tip to form a curtain film 7 and to the support 9 at a constant speed. Collision is applied. At this time, the inside of the liquid supply head 4 is completely sealed by the coating liquid, and care must be taken so that bubbles do not stay. For this reason, bubbles that have not completely been removed by the vacuum defoaming machine and the horn-shaped tube that has spread upwards and that have entered are overflowed from the manifold in the liquid supply head. It must be removed from the tube 17 and prevented from penetrating into the curtain. At this time, the flow rate of the overflow must be a level at which the internal pressure in the head is maintained at a certain level or more, and the flow rate must sufficiently discharge bubbles in the curtain. Therefore, it goes without saying that the flow rate sent from the metering pump 3 needs to be a flow rate that allows for the overflow in addition to the required coating flow rate. Finally, the coating solution on the support is dried with a drying device 13 in a required amount of water to obtain a color former sheet 14 of the present invention.

To maintain the formed curtain film 7 in a stable state, edge guides 8 are provided at both ends (in FIG. 1, they overlap with the curtain film 7). The vertical curtain film 7 formed by the coating liquid 1 collides with the continuously running support 9 and is coated on the support 9. Here, the edge guide 8 does not exceed the width of the liquid supply head 4,
And the curtain film is formed over the width of the support 9. The reason why the curtain film 7 is formed to exceed the width of the support 9 is to prevent thick coating of the coating film at both ends of the curtain film 7. The coating liquid 1 flowing down over the width of the support 9 is collected in a liquid receiving tank 10, returned to the storage tank 2, and coated again. Also, when the coating is interrupted such as when the support 9 is cut, the coating liquid 1 is collected in the liquid receiving tank 10.

The support 9 and the curtain film 7 running continuously
On both sides of the contact portion (hereinafter, referred to as a "coating portion"), the air flow accompanying the support 9 is shielded, and the curtain film 7 is disturbed by the circulation of air around the curtain. Wind shield plates 11a and 11b are provided so as to reach the support 9 without any trouble. In addition, the direction of conveyance of the support 9 is changed by the support roll 12 immediately before the coating section, so that the influence of the airflow guided to the support 9 on the coating section is minimized. Is configured. Further, the wind shield plate 11 is provided so that the curtain film is not affected by the influence of the surrounding air.
It is preferable that a and 11b are installed as close to the support and the curtain as possible.

In order to apply the formed curtain film 7 in a stable state, a certain height from the support 9 to the tip of the slit is required. In the present embodiment, the height is required. The height suitable for stabilizing the curtain film 7 is 5 to 30 cm, preferably 10 to 25 cm.
cm is appropriate.

When the coating is not performed, the liquid of the curtain is poured into the receiving plate 18.
The coating is started by receiving and moving at, and the coating is completed by returning the tray.

In the present embodiment, the coating liquid is not subjected to the action of high shear stress or the like from the outside in the coating process, and since the pre-metering method is used, water is selectively absorbed by the support and the coating liquid is removed. Since the concentration does not increase, the composition of the coating liquid does not change with time even if the coating liquid is recycled and reused. And the effect can be expected even when the coating speed is increased.

Since the amount of the coating solution is measured in advance and then applied onto the support, the amount is minimized, and the amount of the coating solution is excessive as in a blade or an air knife coater. And the amount of liquid supply is 1/5 or less. In a method in which a coating liquid is formed on a curtain film by pressurization and is applied by colliding with a support, the coating amount is determined by the traveling speed of the support 9 and the supply of the coating liquid per unit time. It is determined by the volume, but theoretically the minimum liquid supply is the car
This is an amount capable of stably forming a ten film, which is an extremely small amount.

It is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified. In the above-described embodiment, the width of the formed curtain film is larger than the width of the support 9, but this is to prevent an increase in the coating amount at both ends of the coating layer. If the increase in coating amount is small or not so much a problem, or if it can be resolved by adopting a method disclosed in Japanese Patent Publication No. 49-14130 and other methods for preventing an increase in coating amount, The curtain 7 is supported on the support 9.
It may be equal to or slightly smaller than this width.

The true specific gravity referred to in the present invention is, specifically, a degree of vacuum of 60 mmHg or less and a rotation speed of the dispersion plate of 1 in a vacuum defoamer.
After the treatment under the condition of 500 rpm or more, the amount is obtained from the weight when a 1000 ml graduated cylinder is filled with a coating liquid obtained by adding an extremely small amount of an alcohol-based antifoaming agent represented by n-octyl alcohol.

In the present invention, the coating liquid containing microcapsules as a main component is generally a solution obtained by dissolving or dispersing microcapsules in water together with a binder and a protective agent, and includes microcapsules, a binder and a protective agent. Is 10 to 60% by weight. The mixing ratio of the microcapsule, the binder and the protective agent is generally such that the binder and the protective agent are 5 parts by weight or more, preferably 10 to 70 parts by weight, more preferably 30 to 100 parts by weight, based on 100 parts by weight of the microcapsules. Usually, the ratio of the binder to the protective agent is 50 to 200 parts by weight based on 100 parts by weight of the binder.

In the present invention, as a color former, crystal violet lactone, 3-3 bis (P-dimethylaminophenyl) phthalide, 3- (P-dimethylaminophenyl) -3- (2-methylindole-3- Il)-
Triallylmethanephthalide such as 6-dimethylaminophthalide and acyl derivatives such as benzoyl, anisozoyl, and bivaloyl of methylene blue; 3-diethylamino-6-methyl-7-chlorofluoran, 3-diethylamino-7-di Xanthenphthalide such as benzylaminofluoran and the like.

Examples of the color developer include acid clay, natural clay minerals such as attapulgite as an inorganic color developer, activated clay obtained by treating acid clay with a mineral acid, and semi-synthetic solid acid described in JP-A-57-15996. And various organic phenolic compounds, novolak phenolic resins, polyvalent metal salts of aromatic carboxylic acids, and the recently proposed JP-A-63-163.
Polyvalent metal products of salicylic acid resins described in JP-A-186729 and JP-A-63-254124 have already been used.

The color former is dissolved in a high boiling solvent and used as microcapsules. Examples of the high-boiling solvent that dissolves the color former include alkylnaphthalenes represented by diisopropylnaphthalene, diallylalkanes represented by 1-phenyl-1-xylylethane, alkylbiphenyls represented by isopropylbiphenyl, and other triallyldienes. Aromatic hydrocarbons such as methanes, alkylbenzenes, benzylnaphthalenes, diallylalkylenes and allylindanes; carboxylate compounds represented by dibutyl phthalate, dioctyl maleate; etc .; tricresyl phosphate Typical examples include phosphate ester compounds; vegetable oils such as castor oil, soybean oil, and cottonseed oil or modified oils thereof; and high-boiling fractions (consisting of aliphatic hydrocarbons) of natural products such as mineral oils.

There are known methods for producing microcapsules containing a color former, such as a coacervation method, an in-situ method, and an interfacial polymerization method. However, a synthetic resin capable of obtaining microcapsules at a high concentration is used as a wall material. Are preferred.

The microcapsules containing the color former are coated on a support such as paper together with a binder and a protective agent, and the binder is a water-soluble polymer binder such as starch or polyvinyl alcohol. And latex emulsion binders which are hydrophobic polymers of styrene butadiene type, acrylic type and vinyl acetate type. The protective agent is added to prevent unintended destruction of the microcapsules. Generally, a protective agent having a particle diameter of about 2 to 10 times the particle diameter of the microcapsules is used. Specifically, wheat starch, Potato starch, cellulose fine powder, synthetic resin fine particles and the like are used.

As the support, acid paper and neutral paper mainly containing cellulose fibers are usually used, but sheets made of synthetic resin such as synthetic paper can also be used. At this time, if the support has a Beck smoothness of 10 seconds or less based on the JISP8119 method, the boundary layer of air entrained by the support becomes thicker and a higher collision speed is required, which is not preferable.

In the present invention, the weight solids concentration of the coating liquid containing microcapsules as a main component is not particularly limited, but since the head pressure needs to be constantly increased to a certain level or more, B An arbitrary liquid concentration such that the mold viscosity is preferably 30 cps or more, more preferably 70 to 500 cps, is required. The coating amount on the support is 2 g / m ² or more, preferably ^{3 to 6} g, on a dry weight basis.
/ M ² is appropriate.

[0044]

(Coating liquid component)

 40% microcapsule dispersion 100 parts Wheat starch (particle diameter 20 μm) 50 parts 48% carboxy-modified styrene butadiene copolymer latex emulsion 20 parts Water 79 parts

The coating solution thus obtained was applied to a width 1 shown in FIG.
After defoaming to a specific gravity of 1.03 (99% of the true specific gravity) with a vacuum defoamer using a pressure type liquid supply head having a slit gap of 000 mm and 0.2 mm, 11.0 liter / min. A uniform curtain film was formed by supplying the liquid at a rate of 1000 m / min on a high quality paper 900 mm wide and 40 g / m ² weighing 10 cm away from the slit. A colorant sheet for non-carbon pressure-sensitive copying paper having a work volume of 4 g / m ² in absolute dry solid content was obtained. At this time, before supplying the liquid to the liquid supply head, a coating liquid of 0.7 liter / min is overflowed from the upper part of the horn-shaped tube which spreads upward, and further, the inside of the liquid supply head is further reduced. The coating liquid was overflowed from the manifold at 0.3 liter / min to remove bubbles. At this time, the curtain film was not clogged even after 24 hours, and the coating surface did not show any small uncoated portions due to bubbles, and a uniform microcapsule coating layer was obtained. .

Example 2 In Example 1, the specific gravity was 1.01 (97% of the true specific gravity) by operating only the vacuum defoamer without performing each overflow.
Example 4 was carried out in the same manner as in Example 1 except that the processing solution was supplied at a supply rate of 10 liters / minute, and the absolute dry solid content was 4 g / m ² .
A color former sheet for carbon pressure-sensitive copying paper was obtained. At this time, the curtain film did not close even after 24 hours,
In the coated surface, the number of small uncoated portions caused by bubbles was about 5 / m ² or less, which was a level that was not a problem in practical use.

Example 3 In Example 1, the specific gravity was 0.99 (95% of the true specific gravity) by operating only the vacuum defoamer without performing each overflow.
Example 4 was carried out in the same manner as in Example 1 except that the processing solution was supplied at a supply rate of 10 liters / minute, and the absolute dry solid content was 4 g / m ² .
A color former sheet for carbon pressure-sensitive copying paper was obtained. At this time, the curtain film did not close even after 24 hours,
The number of small uncoated portions caused by bubbles on the coated surface was about 50 pieces / m ² , but at a level that was almost no problem in practical use.

Example 4 In Example 1, the overflow from the manifold was performed.
Without performing the above steps, the upper part of the horn-shaped tube is expanded from the top by 0.1 mm.
9. Overflow the coating solution at 7 liter / min.
The same procedure as in Example 1 was carried out except that the solution was supplied at a supply rate of 7 liters / minute to obtain a color developing agent sheet for non-carbon pressure-sensitive copying paper having a dry solid content of 4 g / m ² . At this time, the curtain film is 2
Although no clogging occurred even after 4 hours, the number of small uncoated portions caused by bubbles on the coated surface was about 10 / m ^2.
However, the level was not a problem in practical use.

Example 5 In Example 1, the horn-shaped tube expanding from the upper side
Example 1 was the same as Example 1 except that the coating liquid was overflowed from the manifold at a rate of 0.3 L / min without performing the overflow, and supplied at a supply rate of 10.3 L / min. Do the same,
A color developing agent sheet for non-carbon pressure-sensitive copying paper having an absolutely dry solid content of 4 g / m ² was obtained. At this time, the curtain film did not close even after 24 hours, but the number of small uncoated portions caused by bubbles on the coated surface was about 10 / m ^2. There was no level.

Comparative Example 1 In Example 1, the vacuum defoamer was operated and the specific gravity was 0.97.
(93% of the true specific gravity), and apply 0.7 L / min of the coating solution from the top of the horn-shaped tube spreading upward.
The coating liquid is allowed to flow, and the coating liquid is overflowed from the manifold in the liquid supply head at a rate of 0.3 liter / min.
Example 1 except that the liquid was supplied at a supply rate of 1.0 liter / min.
In the same manner as described above, a colorant sheet for non-carbon pressure-sensitive copying paper having a dry solid content of 4 g / m ² was obtained. At this time, the number of small uncoated portions caused by bubbles on the coated surface was about 100 /
m ² occurred, and the commercial value was low. Further, the curtain film tended to be clogged after 18 hours.

Comparative Example 2 In Example 1, the vacuum defoaming machine was operated and the specific gravity was 0.97.
(93% of the true specific gravity) The processing liquid was supplied in the same manner as in Example 1 except that the liquid was supplied at a supply rate of 10.0 L / min without performing any overflow. 4g / m in minutes
^A color former sheet for No. ² carbon black pressure-sensitive copying paper was obtained. At this time, small uncoated portions caused by bubbles on the coated surface were generated at about 1000 pieces / m ² , which was not very usable as a commercial product. Further, the curtain film tended to be clogged after 3 hours.

Comparative Example 3 In Example 1, the vacuum defoamer was operated and the specific gravity was 0.97.
(93% of the true specific gravity), and apply 0.7 L / min of the coating solution from the top of the horn-shaped tube spreading upward.
Flow - is allowed 10.7 liters / min other than those supplied by the liquid supply amount is performed in the same manner as in Example 1, 4g / m ² absolute dry solids
A color developing agent sheet for a non-carbon pressure-sensitive copying paper was obtained. At this time, about 500 pieces / m ^{2 of} small uncoated portions caused by bubbles were generated on the coated surface, and it was not very usable as a commercial product. Further, the curtain film tended to be clogged after 10 hours.

Comparative Example 4 In Example 1, the vacuum defoaming machine was operated and the specific gravity was 0.97.
(93% of the true specific gravity), without overflowing from the horn-shaped tube which spreads upward, and applying 0.3 L / min of the coating solution from the manifold. Bar flow, 1
Example 1 except that the liquid was supplied at a supply rate of 0.3 liter / min.
In the same manner as described above, a color developing agent sheet for non-carbon pressure-sensitive copying paper having a dry solid content of 4 g / m ² was obtained. At this time, the number of small uncoated portions caused by bubbles on the coated surface was about 500 /
m ^{2 was} generated and was not very usable as a product. Further, the curtain film tended to be clogged after 10 hours.

Comparative Example 5 The coating liquid obtained in Example 1 was 900 mm in width and 40 g in basis weight.
/ M ² high quality paper, head height 10cm, width 1000m
Using a free-fall type (non-pressurized type) curtain coater having a slit gap of 0.2 mm and 0.2 mm, a horn type that expands upward before the liquid is supplied to the liquid supply head as in the first embodiment. The coating solution was allowed to overflow from the upper part of the tube at 0.7 liter / min.
The coating liquid was overflowed at a rate of 3 liters / minute, coated at a curtain flow rate of 11.0 liters / minute at a coating speed of 1000 m / minute, and dried. 4g /
m2 of a color developing sheet for a non-carbon pressure-sensitive copying paper was obtained.
At this time, no small uncoated portions caused by bubbles were found on the coated surface, and a uniform microcapsule coating layer was obtained. However, the curtain film tended to be clogged after 18 hours. Was seen.

[0055] In Comparative Example 6 Example 1, a pressure type force - Tenko - data - instead, air - Naifuko - data - in the same manner as smeared Example 1, absolute dry solids content of 4g / m ² Bruno - A color former sheet for carbon pressure-sensitive copying paper was obtained. At this time, the target coating amount could not be obtained even when the air pressure was maximized.

(Coloring Agent Sheet Evaluation Method) 発 Coloring property: The obtained coloring agent sheet was combined with a commercially available Mitsubishi NCR paper super lower paper (N-40) and a super calendar.
(100 kg / cm ² × 2 passes) to evaluate the color development. The color density was measured using a Macbeth densitometer. ◎ Stain resistance: A 15 cm × 15 cm color former sheet is combined with the above-mentioned lower paper of 35 cm × 25 cm, and a weight of 3500 g for evaluation of the stain resistance is placed on the sheet, and a color former sheet is placed.
The stain resistance was evaluated based on the degree of stain when the sheet was pulled at a constant speed. The color density was measured using a Macbeth densitometer.数 Number of missing: The number of missing in the coated paper was visually confirmed.閉塞 Occlusion: The obstruction of the curtain was visually evaluated. Table 1 shows the results of evaluating the above items.

[0057]

[Table 1] * Evaluation criteria Coloring property: The higher the numerical value, the better (the print density is higher) ..... 0.83 or more Stain resistance: The higher the numerical value, the worse (easy to smear) ........... 0.47 or less : Unsmeared with an inner diameter of about 1 mm or more ··· 50 pieces / m ² or less Closing property: ◎ Excellent, ○ Excellent, △ Slightly inferior, × Problem ・ ・ ・···· △ and above Overall evaluation: ◎ Excellent, ○ Excellent, △ Slightly inferior, × Problem ・ ・ ・ ・ ・ ・ △ ～ ○

[0058]

As is clear from the above examples, according to the present invention, a non-carbon layer having high productivity, good color development, excellent stain resistance, and free of uncoated portions on the coated surface. A pressure-sensitive copy paper was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a coating apparatus for a non-carbon pressure-sensitive copy paper of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Coating liquid 2 ... Storage tank 3 ... Pump 4 ... Supply liquid head 5 ... Manifold 6 ... Slit 7 ... Curtain film 8 ... Edge guide 9 ... Support 10 ...... Liquid receiving tanks 11a, 11b ... wind shield plate 12 ... support roll 13 ... drying device 14 ... color former sheet 15 ... vacuum defoaming machine 16 ··· Overflow from horn-type tube 17 ··· Overflow from manifold 18 ···· Drain of curtain liquid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/124 B05C 5/00

Claims (3)

(57) [Claims] 1. A carbon-free pressure-sensitive copying paper coating apparatus which forms a coating liquid on a curtain film from a pressure type liquid supply head having a slit and collides with a support to apply the coating liquid. Before supplying the processing liquid to the supply head, the specific gravity of the processing liquid
Is a carbon-free pressure-sensitive copying paper coating device provided with a vacuum defoaming machine that makes 95% or more of the true specific gravity . 2. After the coating liquid is processed by the vacuum defoamer, the coating liquid is overflowed before being supplied to the liquid supply head.
2. A carbon-free pressure-sensitive copying paper coating apparatus according to claim 1 , further comprising a horn-shaped tube which is widened and widened . 3. A coating apparatus for carbonless pressure-sensitive copying paper according to claim 1 , further comprising a pipe for overflowing the coating liquid from a manifold in the liquid supply head.