JP3193075B2 - Manufacturing method of coated 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 method for producing coated paper, for example, a method for producing a high-quality heat-sensitive recording sheet, pressure-sensitive copying sheet, pigment-coated paper, magnetic recording sheet, etc. by using a curtain coating apparatus. It is about.

[0002]

2. Description of the Related Art Examples of typical coated paper include, for example,
In the case of a heat-sensitive recording sheet, it has long been known that a colorless or pale-colored leuco dye and a developer such as an organic acidic substance form a color by a melting reaction when heated. An example of applying the reaction to recording paper is shown in
No. 4160, Japanese Patent Publication No. 45-14039, etc., and are well known. These thermal recording sheets have been applied to a wide range of fields, such as measurement recorders, terminal printers such as computers, facsimile machines, automatic ticket vending machines, and bar code labels. Accordingly, the required quality of the heat-sensitive recording sheet has become higher.

In a pressure-sensitive copying sheet, a coating layer comprising a microcapsule containing a color former, a binder and a protective agent is provided on one side of a support, and a coating layer containing a color developer as a main component is provided on the other side. And those having only one of a coating layer composed of microcapsules and a binder and a protective agent or a coating layer mainly composed of a color developer on one surface of a support. In these, the coating layer containing the microcapsules and the coating layer containing the color developer are brought into contact with each other, and the microcapsules are destroyed by writing pressure, pressure from a typewriter or a printer, and the color former is released, and the color developer is released. The layer comes into contact with a layer containing and develops an image to obtain an image.

[0004] Pigment-coated paper is widely used as printing paper because of its high smoothness and gloss and uniform ink absorption as compared with uncoated high-quality paper. Especially in recent years,
The visualization of printed matter has progressed, the ratio of color printing has increased, and the printing speed has increased, and the demand for printing paper has become even higher.

[0005] Usually, there are a blade coating method, an air knife coating method, a roll coating method, a curtain coating method and the like as a method of applying a liquid material on a web, and the coating method depends on the kind of the coating liquid and the purpose and use of the product. Are selected as appropriate.

For example, a thermal recording sheet is coated by an air knife coating method (eg, US Pat. No. 3,186,851).
No. 3,472,674, British Patent No. 1,17
6,469), a blade coating method (for example, Japanese Patent Publication No. 49-35330, British Patent No. 1,339,082, etc.), a wire bar coating method, a curtain coating method (Japanese Patent Application Laid-Open No.
4-74761).

Further, as a method of applying a pressure-sensitive copying sheet,
Conventionally, an air knife coating method, a blade coating method, and a curtain coating method (for example,
No. 239) has been used.

[0008] Further, there are a wide variety of methods for applying the printing paper on which the pigment is applied, and specific examples thereof include a blade coating method, an air knife coating method, and a roll coating method. A common feature of these coating methods is that a coating liquid containing a pigment as a main component can be applied by a relatively simple operation. However, with these coating methods, high quality printing paper could not be obtained.

The air knife coating method is a post-measurement type coating method in which an excess coating liquid is supplied to a web and then excess liquid is scraped off by wind pressure. In such a coating method, a pattern peculiar to the air knife is easily generated in the coating layer, and as a result, the gloss and smoothness of the surface of the coating layer are significantly reduced, and not only the quality is reduced, but also a serious obstacle at the time of printing. Become. Also,
In such a coating method, when the coating speed is increased or when the liquid concentration is increased, it is necessary to increase the wind pressure, but when the wind pressure is increased, the turbulence of the air flow occurs. Also, the noise due to the blowing becomes remarkable. Therefore, since the wind pressure cannot be increased unnecessarily, it is not suitable for the production of pigment-coated paper which is required to apply a relatively high-viscosity liquid at a high speed.

[0010] The blade coating method is a post-metering coating method in which an excessive coating liquid is supplied to a web and then excess liquid is scraped off by a blade. However, in such a coating method, between the supply of the excess liquid and the measurement, the water or the binder component in the coating liquid infiltrates the web more than necessary, and a high pressure is applied to the coating liquid immediately below the blade during the measurement. For,
Infiltration of water or binder components in the coating liquid into the web proceeds more remarkably. For this reason, in the pigment coating layer,
Since the amount of the binder component is relatively small, the strength of the coating layer is low, and high gloss is hardly developed. Also, the liquid scraped off as a surplus differs from the composition of the liquid before supply,
As the time elapses, the composition of the coating solution changes, and a product of stable quality cannot be obtained. In addition, when a pigment dispersion is applied by such an application method, occurrence of application defects such as streaks and scratches is inevitable.

There are various types of roll coating methods depending on the combination of rolls and the like. Basically, a plurality of rolls are combined and the liquid is measured and transferred to the web by transferring the coating liquid between the rolls. It is a coating method. Such a coating method easily generates a roll-specific pattern,
When the coating roll surface and the web are separated after transfer, the gloss and smoothness of the coating surface are reduced, and it is difficult to satisfy the quality requirements for printing paper in recent years.

In each of the air knife coating method and the blade coating method, after excessively applying a coating solution to a web, the excess coating solution is scraped off with an air knife or a blade, and the amount of the coating solution is measured to a desired amount and scraped off. The recovered coating solution is collected and reused by circulation.

However, it has been difficult to obtain a high quality coated paper efficiently by such a coating method.
That is, in the air knife coating method, when an excess liquid is scraped off with an air knife, a unique air knife pattern is often generated on the coating surface, and similarly in the blade coating method, when the excess liquid is scraped off with a blade, a scratch or the like is generated. Streaks often occur, and it has been extremely difficult to obtain high quality products.

However, it has been difficult to efficiently obtain a high-quality pressure-sensitive copy sheet by such a coating method. That is, in the case of the air knife coating method, a large particle size protective agent is scraped off more than necessary due to the classification action by the air knife, and also in the case of the blade coating method, a classification action occurs in the gap between the blade and the web, The protective agent having a high probability of coming into contact with the blade was scraped off more than necessary, and as a result, it was extremely difficult to apply a desired amount of the protective agent. In addition, the classification effect of the air knife or blade becomes more remarkable as the coating speed increases, and this is a major barrier to increasing the coating speed.

On the other hand, the excess coating solution scraped off by an air knife or blade is usually collected and recycled for reuse, but the solid content concentration in the coating solution gradually increases due to the above-described classification action, and the solution composition becomes aging. Therefore, it was difficult to obtain a stable quality product.

The curtain coating method is a coating method that solves the problems in the air knife or blade coating method. However, since the curtain coating method is a so-called pre-metering type coating method in which the coating liquid is supplied to a support, that is, measurement is performed simultaneously before the coating is performed, the coating liquid flowing down from the head as a curtain film is applied. The flow rate profile in the width direction directly reflects on the application amount profile in the width direction of the product.

In a conventional apparatus which does not have a mechanism for adjusting the flow rate profile in the width direction of the curtain film, there is no means for correcting the uneven flow rate profile of the curtain film flowing down. Differences in color density in the width direction, distorted winding of the product, wrinkles may occur, and if it is remarkable, the paper may break in the finishing or printing process. Often caused problems.

Further, the unevenness of the curtain film profile in a coating apparatus having no mechanism for adjusting the flow rate profile in the width direction of the curtain film becomes remarkable as the length of the coater head in the width direction, that is, the coating width becomes wider. In addition, when the coating width, which is important as a means for improving productivity, is increased, it becomes difficult to perform uniform coating in the width direction. This tendency is remarkable when the flow rate of the coating liquid per unit width of the head is large. That is, in a high-speed coating operation requiring a large flow rate, it is difficult to perform a high-speed and wide-width coating operation with a coating apparatus that does not have a mechanism for adjusting a flow rate profile.

Adjusting the flow rate profile by changing the opening of the tip of the outflow slit in the width direction is a method usually performed by an extruder head or a die head used for lamination. It is possible to apply to the head.

However, since the adjustment is performed manually after measuring the application amount profile after the application, the loss is large in time, and therefore, the productivity is greatly reduced. This means that in the case of a wide coating apparatus having a wide coating width, the distance to be adjusted in the width direction is long, so that the time loss is greater.

[0021]

SUMMARY OF THE INVENTION The present invention solves the problems of the above-mentioned various coating methods by using a curtain coating apparatus provided with a mechanism for controlling the coating amount profile in the curtain width direction. It is an object of the present invention to provide a method for producing coated paper having high quality and a uniform coating amount in the width direction.

[0022]

According to the present invention, there is provided a method for producing a coated paper obtained by applying a coating liquid, wherein a curtain film thickness profile is measured optically in a width direction and converted into a flow rate value. Using a curtain coating device provided with a mechanism for controlling the slit opening of the head corresponding to the coating amount profile, controlling the slit opening of the coating head, converting the thickness profile of the curtain film into a voltage value or a current value, The measurement is performed by heating a metal mass in contact with the coater head to cause thermal expansion of the metal mass, and further, a curtain film thickness profile measurement is performed by using an optical density gradation of a curtain film and an optical density gradation of a blank exposure. And the extinction coefficient a is 8
It has been found that when the ratio is in the range of 0 to 250, a coated paper having a thin coating layer and a uniform coating layer free from coating defects can be obtained.

According to the present invention, in a curtain coating apparatus, a visible or ultraviolet light source is used as a light source, and
The thickness profile of the curtain film corresponding to the application amount profile is measured by a device using a light receiving element and a light source unit installed on the opposite side of the light receiving unit with a curtain film therebetween. Further, based on the thickness profile of the curtain, a computer performs arithmetic processing to control the slit opening of the coater head. To adjust the slit opening,
There are various methods, but the best method is to convert the thickness profile of the curtain film into a voltage value or a current value, heat a metal lump in contact with the coater head, and adjust the opening degree using the thermal expansion of the metal lump. How to do it. Heating methods include heat transfer heating by a heater and induction heating by generating an electric field by a coil, but induction heating is excellent in terms of responsiveness.

The detailed description of the present invention is shown below. Optical curtain thickness measurement is possible when the curtain film has optical density. As shown in Equation 1, it can be seen that the film thickness can be measured from the density gradation at the time of blank exposure and at the time of curtain film exposure.

[0025]

[Number 2] x = - (1 / a) · ln (G / G B) ( Equation 1) X: Curtain thickness a: extinction coefficient (cm ^-1) (constant) G: optical density gradation of the curtain film (corresponding to the amount of transmitted light) G _B: optical density gradation of a blank exposure (corresponding to the amount of source light)

According to this, it is apparent that the film thickness measurement can be performed by measuring the amount of transmitted light of the curtain film at the same position as the blank measurement using only the light source. In the following, to make this principle clearer,
It proves that the film thickness can be calculated from the transmitted light amount of the film.

Curtain thickness x (cm) and transmitted light intensity I (lx)
Assuming that the power law is established between the following, the following equation is established.

[0028]

## EQU3 ## I = I ₀ · exp (−a · x) I ₀ : incident light intensity (lx)

[0029]

P = I · t P: transmitted light amount (lx · sec) t: exposure time (sec)

From equations (3) and (4),

[0031]

P = P ₀ · exp (−a · x) P ₀ : incident light amount (lx · sec)

[0032]

[6] ^{V = S · P r + V0} V: output voltage of the light receiving element (V) P: amount of transmitted light (lx · sec) S: Sensitivity r = 1 (in general can be adjusted to this value) V ₀ : Dark output voltage

From equations (5) and (6),

[0034]

V−V ₀ = S · P ₀ · exp (−a · x)

If the output voltage in the case of blank exposure (x = 0) is V _B ,

[0036]

V _B -V ₀ = S · P ₀

From equations (7) and (8),

[0038]

X = − (1 / a) · ln [(V−V ₀ ) / (V _B −V ₀ )]

Further, since there is a linear relationship between the output voltage V (V) of the light receiving element and the optical density gradation G of the curtain film captured by the light receiving element,

[0040]

G = k (V−V ₀ ) k: Normalized constant

[0041] The optical density gradation of a blank exposure G _B
Then

[0042]

[Number 11] _{G B = k (V B -V} 0)

From Equations 9, 9, and 11, Equation 1 (Equation 1) can be derived.

Here, the extinction coefficient a is a constant inherent to the coating solution. When the extinction coefficient a increases, the amount of light transmitted through the curtain film decreases, so that it becomes susceptible to disturbance light other than the measurement light source. Specifically, when the extinction coefficient a exceeds 250, the curtain Light shielding around the coating head is required, and the measurement time of the film thickness profile becomes longer, so that profile control cannot be performed well.

When the coating liquid becomes optically transparent, that is, when the extinction coefficient a decreases, the difference between the amount of blank light and the amount of light transmitted through the curtain decreases, so that the influence of turbulence and fluctuations in the flow of the curtain film increases. As a result, accurate measurement cannot be performed. Specifically, the extinction coefficient a is 8
It is desirable to perform the measurement at 0 or more. Therefore, the extinction coefficient a of the coating solution when controlling the curtain profile
Is desirably 80 to 250.

As a light source for measurement, a light source that does not change in light amount with time is desirable, and specific examples include a fluorescent lamp, an incandescent lamp, a halogen lamp, a semiconductor light emitting element, a laser light emitting element, and the like. Further, it is desirable that the light receiving element has a small change in sensitivity over time.
Cameras, photodiodes, photodiode arrays,
There are CdS elements and photomultiplier tubes.

FIG. 1 shows a typical example of an apparatus for measuring a film thickness profile of a curtain by mechanically scanning in the width direction using a combination of a light source and a light receiving element. The light irradiated by the light source unit 3 is partially absorbed or scattered by the curtain film 2 formed by flowing out the coating liquid from the coater head 1, and the rest is transmitted and is on the optical axis of the light irradiated by the light source unit 3. The light reaches the light receiving unit 4 located there.

At this time, it is desirable that the light emitted from the light source has a finite irradiation area with a clear boundary on the curtain film by a parallel light or an optical focusing method. The size of the irradiation area is usually 1 μm to 100 mm in diameter,
Preferably, a diameter of 1 mm to 10 mm is appropriate. Specifically, a laser light source is a typical example.
In addition, if light is focused optically, it is possible to use an incandescent lamp, a semiconductor light emitting element, a halogen lamp, or the like. Furthermore, in order to eliminate the influence of external light, a focus may be focused on the light receiving element using an optical lens. However, if the amount of transmitted light is large enough for external light,
It is not necessary to use an optical lens to focus on the light receiving element.

The light detected by the light receiving section is usually converted into a voltage value corresponding to the light amount. This is computer 5
Performs A / D conversion, stores the data in an internal memory, performs arithmetic processing, outputs a control signal to the induction heating device, and controls the outflow flow profile from the coater head. Also,
In order to measure the thickness profile in the width direction of the curtain, it is necessary to move the light source and the light receiving unit in parallel to the curtain film in the width direction without changing the optical axis,
This is desirably controlled by the computer 5 using a stepping motor for driving the light source and the light receiving unit on the moving stage 6. Here, when measuring the blank, the outflow of the coating liquid from the head is stopped, and the measurement is performed in a state where the curtain film is not formed.

Further, FIG. 2 shows a typical example of an apparatus for measuring a film thickness profile of a curtain by fixing a light source and a light receiving section by a combination of a light source and a light receiving element. The light irradiated from the light source unit 3 is partially absorbed or scattered by the curtain film 2 formed by flowing out the coating liquid from the coater head 1, and the rest is transmitted, and the transmitted light is focused on the curtain film. The light reaches the light receiving section 4 having a plurality of pixels in the width direction of the curtain film. The number of pixels required is 512-204 per meter
Eight pixels are appropriate.

At this time, it is desirable that the light source has a light amount as uniform as possible in the width direction.
A rod-shaped fluorescent lamp is most desirable as a light source.

When measuring the thickness profile of a curtain at a fixed point using a light receiving element having a plurality of pixels, at the center of the measurement, light passes vertically through the curtain film and reaches the light receiving section. At the end, light passes obliquely through the curtain film and reaches the light receiving portion. Therefore, even if the thickness of the curtain film is uniform in the measurement direction, the end becomes apparently thicker. This becomes significant when the measurement width is increased with respect to the distance between the light receiving unit and the curtain film. Therefore, after the data is collected, it is necessary to correct the data inside the computer.

Normally, it is converted into a voltage value corresponding to the amount of light,
The computer 5 performs A / D conversion, stores the data in an internal memory, performs arithmetic processing, outputs a control signal to the induction heating device, and changes the temperature of the profile adjustment block 19. Since the profile adjustment block 19 causes a volume change due to a temperature change, if a plurality of profile adjustment blocks 19 are arranged in the width direction, the flow rate profile in the head width direction can be controlled by changing the induction heating temperature. is there.

FIG. 3 is a sectional view of a coater head provided with a profile adjusting mechanism. To adjust the profile, the flow rate is adjusted by elastically deforming the profile plate 16 by the volume change of the profile adjusting block 19 and adjusting the gap between the liquid flow paths. The volume change of the profile adjustment block 19 is determined by the coils 18a, 18
An electric field is generated by energizing b, and thermal expansion by induction heating is used. The heat insulating material 17 is provided to prevent the heated heat of the profile adjustment block 19 from directly heating the coater head.

When measuring a blank, the outflow of the coating liquid from the head is stopped, and the measurement is performed in a state where the curtain film is not formed. In addition, the blank measurement is indispensable for correcting unevenness of illuminance in the width direction of the light source, or correcting for vignetting in the optical lens.

When comparing the measurement methods of FIGS. 1 and 2, the measurement principle is exactly the same, but there is a difference in the structure or operation of the device. In FIG. 1, since the light source and the light receiving unit scan mechanically, the device becomes slightly larger, the control becomes complicated, and the time required for measurement becomes slightly longer than in FIG. 2. However, when light scattering occurs in the curtain film,
Since the optical axis always exists on the perpendicular line to the curtain film surface, it is not affected by scattering, and the range of selection of the distance of the light source or the light receiving unit from the curtain film is wider than that in FIG. As described above, there is a slight difference between the two systems in the structure and operation of the apparatus, but the principle is completely the same, so that the selection may be made in consideration of the installation location of the apparatus.

If the curtain film has an uneven thickness in the width direction, the curtain film is easily broken at a thin portion. The unevenness of the thickness of the film is more likely to occur as the falling width of the curtain film increases, and it becomes more difficult to form a uniform curtain film. On the other hand, when the flow rate in the width direction of the curtain film becomes uniform, the curtain film can obtain a stable state in a wide flow rate range, and can perform a wide and high-speed coating operation in a stable state.

Even when the curtain coating device provided with such a profile control mechanism is applied to a coating liquid coating operation, the coating operation can be performed in a stable state.

However, in order to perform the coating operation in a stable state, there is an upper limit to the concentration of the coating solution. As the solid content concentration increases, the distance between particles such as pigments, color formers, and developer microcapsules decreases. As a result, the fluidity of the liquid shifts from a viscous behavior to a plastic behavior, the coating liquid becomes “brittle”, and it becomes difficult to form a thin liquid film such as a curtain film. The preferred concentration range of the coating solution is a solid content concentration of 40% or less in the case of a heat-sensitive recording sheet, a solid content concentration of 45% or less in the case of a pressure-sensitive copying sheet, and a solid content concentration in the case of a pigment-coated paper. Is 65% or less.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 4 is a schematic view of a coating apparatus for coating a coated paper showing an embodiment of the present invention. The coating liquid prepared in advance is supplied from the coating liquid storage tank 9 to the liquid supply pump 1.
5 to the coater head 1. At this time, since the amount of application liquid is proportional to the amount of application of the final product,
It is necessary to control the amount of the coating solution sent to the coater head 1 with high accuracy. Therefore, a variable flow type non-pulsating constant flow pump is suitable as the liquid supply pump 15.

As described above, the present invention is characterized in that the coating layer in contact with the web is smeared by a curtain coating method. The coating liquid is sent to a coater head provided with a profile control mechanism, and the width of the coating layer is adjusted. This is based on a curtain coating method in which a vertical curtain film having a uniform profile in the direction is formed and applied on a base paper. By the way, the production of general coated paper by a curtain coating apparatus has been very commonly performed conventionally, as already disclosed in British Patent No. 1,279,817, and for pressure-sensitive copying paper. The production of a color former sheet is disclosed in JP-B-63-239. The production of a heat-sensitive recording sheet is disclosed in JP-A-54-74761. However, by applying a curtain coating device equipped with a profile control mechanism to the application of a heat-sensitive coating solution, a coating solution containing microcapsules as a main component, a pigment coating solution, etc., even if the coating operation is performed for a long time, the coating may be uneven. There has not yet been disclosed any method that can perform a stable coating operation without causing any problem and obtain a high-quality coated paper with a uniform coating amount in the width direction.

The coating liquid supplied to the coater head 1 is
It flows out from the lower part of the head and forms a vertical curtain film 2. At this time, the curtain film thickness profile is measured based on the device principle of FIG. 1 or FIG. 2, and a control signal is sent to the induction heating device based on the device principle of FIG. Control the thickness profile to be uniform.

The vertical curtain film 2 having a uniform profile in the width direction comes into contact with the continuously running web 10 and is applied to the web 10. Here the edge guide 11
a and 11b are provided not exceeding the width of the coater head 1 and further exceeding the width of the web 10, and the vertical curtain film is formed exceeding the width of the web 10. The vertical curtain film 2 is formed so as to exceed the width of the web 10 in order to prevent thick coating of the coating film at both ends of the vertical curtain film 2. The coating liquid flowing down beyond the width of the web 10 is collected in the liquid receiving tank 13, returned to the coating liquid storage tank 9, and then applied again. Also, when the application is interrupted such as when the web 10 is cut, the application liquid is collected in the liquid receiving tank 13.

A contact portion between the continuously running web 10 and the vertical curtain film 2 (hereinafter, referred to as an “applying portion”) shields an air flow accompanying the web 10 and circulates air around the curtain. A wind shield 14 is provided to allow the vertical curtain film 2 to reach the web 10 without disturbing. The transport direction of the web 10 is changed by the roll 12 immediately before the application section, so that the influence of air accompanying the web 10 on the application section is minimized.

In order to apply the formed vertical curtain film 2 in a stable state, it is necessary to remove the coater head 1 from the web 10.
Although a certain height is required to the lower outflow portion, the height can be controlled in this embodiment, and the height suitable for stabilizing the vertical curtain film 2 is 60 to 30.
0 mm, preferably 100 to 250 mm, more preferably 120 to 180 mm.

In the present embodiment, the coating liquid is not subjected to an action such as a higher shear stress than the outside in the coating process, and the pre-metering method is used, so that water is selectively absorbed by the web, and the coating liquid becomes highly concentrated. Since the composition of the coating solution does not change with time even if the coating solution is circulated and reused, it is possible to produce a stable coated paper, and it is possible to increase the coating speed. The effect can be expected.

Further, since the amount of the coating solution is measured in advance and then applied onto the web, the amount of the coating solution is minimized, so that the coating solution is not excessively supplied unlike the blade or air knife coating method. The supply amount is と or less. In a curtain coating method in which a vertical curtain film is formed and coated on a web, the coating amount is determined by the traveling speed of the web 10 and the supply amount of the coating solution per unit time. In theory, the minimum supply amount is This is an amount capable of stably forming the vertical curtain film, which is an extremely small amount.

It is needless to say that the present invention is not limited to the above-described embodiments, but can be variously modified. In the above-described embodiment, the width of the formed curtain film is larger than the width of the web 5, but this is to prevent an increase in the coating amount at both ends of the coating layer. Or if the problem is not so significant, or if the problem can be solved by adopting a method disclosed in Japanese Patent Publication No. 49-14130 or other methods for preventing an increase in the coating amount, the vertical curtain film may be used as a web 5. It may be equal to or slightly smaller than this width.

The coated paper of the present invention refers to a paper obtained by applying a coating composition such as a heat-sensitive recording sheet, a pressure-sensitive copying sheet, a pigment-coated paper, a magnetic recording sheet or the like to the surface of a web. As the web used in the present invention, paper is mainly used, and wood pulp, synthetic pulp, filler, sizing agent, paper strength enhancer, dye, and the like, as required, high-quality paper using raw materials usually used in papermaking, It is possible to use medium-quality paper, reprinted paper, synthetic paper, and the like. In addition, synthetic paper, plastic film, non-woven fabric,
A processed paper such as a woven fabric or a laminated sheet, or a combination thereof may be used. Further, it includes machine-coated paper, art paper, cast-coated paper, resin-coated paper, and the like.

The present invention is not limited to the application of a coating layer, but can be applied to the application of an overcoat layer and an undercoat layer. Further, these coatings may be performed after the lower coating layer is dried, or may be performed without drying, and any method may be employed.

Next, the coating solution to be applied will be described. For example, the heat-sensitive recording material used in the heat-sensitive recording sheet of the present invention may be any combination of a reactant and a co-reactant that cause a color reaction when they come into contact by heat. Combinations with acceptor compounds, combinations of higher fatty acid metal salts such as ferric stearate and phenols such as gallic acid, and the like can be mentioned. Furthermore, there is no particular limitation as long as it is used for a heat-sensitive recording material such as a heat-sensitive recording material in which a diazonium compound, a coupler and a basic substance are combined, and any of them can be used.

However, the effect according to the present invention exhibits a remarkable effect especially in the combination of the electron-donating colorless dye and the electron-accepting compound, and is particularly preferably applicable to such a combination.

Specific examples of the electron-donating colorless dye include triarylmethane compounds: 3,3
-Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone),
3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,
2-dimethylindol-3-yl) phthalide, 3-
(P-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindole-3-
Yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide,
3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (9
-Ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis (2-phenylindole-
3-yl) -5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-methylpyrrole-2
-Yl) -6-dimethylaminophthalide and the like.

The diphenylmethane compounds include:
4'-bis-dimethylaminophenylbenzhydryl benzyl ether, N-2,4,5-trichlorophenylleuco auramine and the like.

The xanthene compounds include: rhodamine B anilinolactam, rhodamine B-p-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7-octylaminofluoran, Diethylamino-7-phenylfluoran, 3-diethylamino-7-chlorofluoran,
3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7- (3,4-dichloroanilino) fluoran, 3-diethylamino-7- (2-chloroanilino) fluoran, 3-diethylamino-6
Methyl-7-anilinofluoran, 3- (N-ethyl-
N-tolyl) amino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tolyl) amino-6
Methyl-7-phenethylfluoran, 3-diethylamino-7- (4-nitroanilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-
(N-methyl-N-propyl) amino-6-methyl-7
-Anilinofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran,
3- (N-methyl-N-cyclohexyl) amino-6
Methyl-7-anilinofluoran, 3- (N-ethyl-
N-tetrahydrofuryl) amino-6-methyl-7-anilinofluoran and the like.

Examples of the thiazine compounds include: benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue and the like.

The spiro compounds include: 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran,
3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 3-propylspirobenzopyran and the like can be mentioned alone or in combination. These can be mixed and used.

The electron accepting compound generally includes a phenol derivative, an aromatic carboxylic acid derivative or a metal compound thereof, an N, N'-diarylthiourea derivative, and the like. Of these, particularly preferred are phenol derivatives.

Specific examples include: p-phenylphenol, p-hydroxyacetophenone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4 ' -Benzenesulfonyloxydiphenyl sulfone, 1,1-bis (p-hydroxyphenyl) propane, 1,1-bis (p-hydroxyphenyl) pentane, 1,1-bis (p-hydroxyphenyl) hexane, 1,1- Bis (p-hydroxyphenyl) cyclohexane, 2,2-bis (p-hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) butane, 2,2-bis (p-hydroxyphenyl) hexane, 1-bis (p-hydroxyphenyl) -2-ethylhexane, 2,2-bis 3-chloro-4-hydroxyphenyl) propane, 1,1-bis (p- hydroxyphenyl) -1-phenylethane, 1,3-di [2-
(P-hydroxyphenyl) -2-propyl] benzene, 1,3-di [2- (3,4-dihydroxyphenyl) -2-propyl] benzene, 1,4-di [2- (p
-Hydroxyphenyl) -2-propyl] benzene,
4,4′-dihydroxydiphenyl ether, 4,4 ′
-Dihydroxydiphenylsulfone, 3,3'-dichloro-4,4'-dihydroxydiphenylsulfone, 3,
3′-diallyl-4,4′-dihydroxydiphenylsulfone, 3,3′-dichloro-4,4′-dihydroxydiphenylsulfide, methyl 2,2-bis (4-hydroxyphenyl) acetate, 2,2-bis ( 4-hydroxyphenyl) butyl acetate, 4,4′-thiobis (2-t
-Butyl-5-methylphenol), bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4′-isopropyloxydiphenylsulfone,
3,4-dihydroxy-4'-methyldiphenylsulfone, benzyl p-hydroxybenzoate, chlorobenzyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, dimethyl 4-hydroxyphthalate, gallic Benzyl, stearyl gallate, salicylanilide, 5-chlorosalicylanilide and the like.

Diatomaceous earth,
Talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, urea-formalin resin,
In order to further improve sensitivity, as additives, waxes such as N-hydroxymethyl stearamide, stearamide, palmitamide, naphthol derivatives such as 2-benzyloxynaphthalene, p-benzylbiphenyl, 4-allyl Biphenyl derivatives such as oxybiphenyl, polyether compounds such as 1,2-bis (3-methylphenoxy) ethane, 2,2′-bis (4-methoxyphenoxy) diethyl ether, bis (4-methoxyphenyl) ether, diphenyl carbonate, Carbonic acid or oxalic acid diester derivatives such as dibenzyl oxalate and di (p-fluorobenzyl) oxalate can be added.

In addition, for the purpose of preventing head abrasion and preventing sticking, higher fatty acid metal salts such as zinc stearate and calcium stearate, and waxes such as paraffin, paraffin oxide, polyethylene, polyethylene oxide, stearic amide and caster wax. ,Also,
A dispersant such as sodium dioctylsulfosuccinate, an ultraviolet absorber such as a benzophenone type or a benzotriazole type, a surfactant, and a fluorescent dye are added as necessary.

As the adhesive used for the heat-sensitive recording layer according to the present invention, any of various commonly used adhesives can be used. For example, starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid A terpolymer, an alkali salt of a styrene / maleic anhydride copolymer, an alkali salt of an ethylene / maleic anhydride copolymer,
Water-soluble adhesives such as polyvinyl acetate, polyurethane, polyacrylate, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, etc. Latex and the like.

Various additives can be further added to the intermediate layer. For example, pigments, surfactants, thermoplastics and the like used for ordinary coated paper may be added.

Next, the pressure-sensitive copying sheet of the present invention will be described. Not only can it be applied to the application of a coating liquid containing microcapsules as a main component, but also a self-coloring type in which a microcapsule containing a color former and a developer are dispersed. The present invention can be applied to the application of a coating liquid or a coating liquid containing a developer as a main component.

In the pressure-sensitive copying sheet of the present invention, the coating liquid containing microcapsules as a main component is generally a liquid in which microcapsules are dispersed in water together with a binder and a protective agent. Is 10 to 60% by weight. The mixing ratio of the microcapsule, binder, and protective agent is generally 10 parts by weight or more, preferably 15 to 100 parts by weight, more preferably 20 to 70 parts by weight, per 100 parts by weight of the microcapsules. The binder is used in an amount of 5 to 7 with respect to 100 parts by weight of the total amount of the microcapsules and the protective agent.
0 parts, preferably 20 to 70 weight.

In the present invention, microcapsules are
It is a microcapsule with a built-in oily substance in which a basic colorless color former is dissolved in a non-volatile solvent, which is covered with a wall material made of a polymer substance insoluble in both water and oily liquid. . As the wall material, a combination of a polycation and a polyanion such as gelatin-gum arabic, a combination of condensation-based compositions such as polyisocyanate-polyamine, and the like are used.

As a method for producing such microcapsules, a phase separation method from an aqueous solution (US Pat. No. 280045)
No. 7, No. 2,800,458), an interfacial polymerization method (Japanese Patent Publication No. 38-19574, No. 42-446, No. 4).
2-771, 42-2882, 42-2883
No. 42-8693, No. 42-9654, No. 42
-11344, British Patent Nos. 950443 and 1046409, etc., and a method of polymerizing a wall material in oil droplets (JP-B-36-9168, JP-B-49-4513).
No. 3 publication) or a melting dispersion cooling method (UK Patent No. 9
No. 52807, No. 965074) and the like.

In the pressure-sensitive copying sheet of the present invention, the color-forming agent has a property of forming a color by donating electrons or by receiving a proton such as an acid, and is not particularly limited. If a specific compound is shown, as a triarylmethane compound: 3,3-bis (p-
Dimethylaminophenyl) -6-dimethylaminophthalide, ie crystal vilet lactone, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-
Dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p- Dimethylaminophenyl)-
3- (2-phenylindol-3-yl) phthalide,
3,3-bis (1,2-dimethylindol-3-yl) -5 dimethylaminophthalide, 3,3-bis (1,
2-dimethylindol-3-yl) -6 dimethylaminophthalide, 3,3-bis (9-ethylcarbazole-
3-yl) -5-dimethylaminophthalide, 3,3-bis- (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-methyl Pyrrol-2-yl) -6-dimethyl-aminophthalide and the like.

As the diphenylmethane compound:
4'-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl-leuco auramine, N-
2,4,5-trichlorophenylleuco auramine and the like.

As a xanthene compound: rhodamine B
-Anilido lactam, rhodamine Bp nitroanilinolactam, rhodamine B-p-chloroanilinolactam,
7-dimethylamino-2-methoxyfluoran, 7-diethylamino-2-methoxyfluoran, 7-diethylamino-3-methoxyfluoran, 7-diethylamino-3-chlorofluoran, 7-diethylamino-3-chloro-2 -Methylfluoran, 7-diethylamino-
2,2-dimethylfluoran, 7-diethylamino-3
-Acetylmethylaminofluoran, 7-diethylamino-3′-methylaminofluoran, 3,7-diethylaminofluoran, 7-diethylamino-3-dibenzylaminofluoran, 7-diethylamino-3-methylbenzylamino-fluoran , 7-diethylamino-3
-Chloroethylmethylaminofluoran, 7-diethylamino-3-diethylaminofluoran and the like.

As the thiazine compound: benzoyl leucomethylene blue, p-nitrobenzyl leucomethylene blue and the like.

As spiro compounds, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-dichloro-spiro-dinaphthopyran,
3-benzylspiro-dinaphthopyran, 3-methyl-naphtho- (3-methoxy-benzo) -spiro-pyran, 3
-Propyl-spiro-dibenzopyran and the like, and mixtures thereof.

These color formers are dissolved in a solvent and encapsulated. As the solvent, natural or synthetic oils can be used alone or in combination. As an example of a solvent,
Cottonseed oil, kerosene, paraffin, naphthenic oil, alkylated biphenyl, alkylated terfel, chlorinated paraffin,
Examples include alkylated naphthalene and diphenylethane. The method of encapsulation has been described above.

In the pressure-sensitive copying sheet of the present invention, the binder may be a latex such as styrene-butadiene-rubber latex, styrene-butadiene-acrylonitrile latex, styrene-maleic anhydride copolymer latex or the like; ,
Water-soluble natural polymer compounds such as casein), cellulose derivatives (eg, carboxymethylcellulose, hydroxyethylcellulose, etc.), saccharose derivatives (eg, agar, sodium alginate, starch, carboxymethyl starch, etc.): polyvinyl alcohol;
Water-soluble synthetic polymer compounds such as polyvinylpyrrolidone, polyacrylic acid, and polyacrylamide: polymers soluble in organic solvents such as nitrocellulose, ethylcellulose, polyester, polyvinyl acetate, polyvinylidene chloride, and vinyl chloride-vinylidene chloride copolymer And the like.

Also, in the pressure-sensitive copying sheet of the present invention,
Protective agents include cellulose fine powder, starch particles, glass beads, microspheres, polymer particles such as polyolefin particles, nylon particles, vinyl chloride particles, methyl methacrylate polymer particles, and mineral particles such as titanium powder and white carbon. , Calcium carbonate, calcium tungstate, zinc sulfide, etc. can be used as long as they have a particle size larger than the microcapsules, but are preferably relatively spherical particles and colorless.

[0096] In pressure-sensitive copying sheet of the present invention, the coating amount is the dry weight criteria of the coating solution mainly composed of microcapsules, 2 g / m ² or more, preferably, suitably 3 to 6 g / m ^2.

Next, the coating liquid for the pigment coated paper of the present invention will be described. In the present invention, a coating liquid containing a pigment as a main component is a liquid dissolved or dispersed in water together with a pigment and a binder, and other additives.
Other additives have a concentration of 10 to 65% by weight. The mixing ratio of the pigment and the binder is generally 100
The binder is used in an amount of 5 parts by weight or more, preferably 10 to 70 parts by weight, based on parts by weight.

Examples of the pigment for coated paper used in the present invention include kaolin, clay, satin white, titanium oxide, aluminum hydroxide, zinc oxide, barium sulfate, calcium sulfate, silica, activated clay, lake, and plastic pigment. Can be

The binder used for the pigment coated paper of the present invention includes various binders such as styrene / butadiene, vinyl acetate / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylic, and vinyl acetate / butyl acrylate. Synthetic adhesives such as polymers and polyvinyl alcohol, maleic anhydride copolymer, isobutene / maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer, oxidized starch, etherified starch, esterified starch, enzyme Commonly known adhesives such as modified starches, cold-water-soluble starches obtained by flash-drying them, and natural adhesives such as casein and soybean protein are included. If necessary, various auxiliaries to be added to ordinary pigments for coated paper, such as a dispersant, a thickener, a water retention agent, an antifoaming agent, a waterproofing agent, and a coloring agent, can be used as appropriate.

The coating solution of the present invention thus obtained is a single or multilayer coating on both sides or one side of the web. For lower layer application in multi-layer coating,
It is also possible to use coating equipment other than curtain coating equipment,
Further, a wet-on-wet coating method in which the upper layer coating is performed without drying the lower layer coating section may be performed.

In the pigment coated paper of the present invention, the coating amount of the coating liquid containing a pigment as a main component is 1 g / m ^{2 on a} dry weight basis.
As described above, preferably, 3 to 30 g / m ² is appropriate.

[0102]

Next, the present invention will be described in more detail with reference to examples. Note that all parts and percentages shown below are based on weight. Further, the value indicating the coating amount is the coating amount after drying unless otherwise specified.

Example 1 A mixture having the following composition was pulverized and dispersed in a sand mill until the average particle size became about 1 μm, and [Solution A] and [B
Liquid] was prepared. [Solution A] 3- (N-methyl-N-cyclohexyl) amino-6
Methyl-7-anilinofluoran: 40 parts 25% aqueous solution of polyvinyl alcohol: 20 parts Water: 20 parts [Solution B] Bisphenol A: 50 parts 2-benzyloxynaphthalene: 50 parts 25% aqueous solution of polyvinyl alcohol: 50 parts Water: 60 parts

Next, using the prepared [Solution A] and [Solution B], a heat-sensitive coating solution (1) having the following composition and a concentration of 40% was prepared. [Solution A]: 50 parts [Solution B]: 250 parts Zinc stearate (40% dispersion): 25 parts 25% aqueous polyvinyl alcohol solution: 205 parts Calcium carbonate: 50 parts

An intermediate layer coating solution having the following composition was prepared. [Intermediate layer coating liquid] Calcined kaolin (manufactured by Ansilex, Engelhard):
100 parts Styrene-butadiene copolymer latex (50% aqueous dispersion): 24 parts Phosphated starch (MS-4600, 10% aqueous solution manufactured by Nippon Shokuhin Kabushiki Kaisha): 60 parts Water: 52 parts

[Coating Method] Using a rod coating device, apply the intermediate layer coating solution to a high quality paper having a basis weight of 40 g / m ² at an application speed of 800 m / min so that the coating amount becomes 5 g / m ² and then dry. After that, using a curtain coating apparatus with a flow width of 600 mm provided with an induction heating type coating amount profile control mechanism, water was added to the coating solution (1) at a coating speed of 400 m / min to reduce the concentration to 13%. % Of the coating solution,
A length of 100,000 m is continuously coated and dried so that the coating amount is 4 g / m ² , and the winding length is 10,000 m.
Of the heat-sensitive recording sheet were obtained. The extinction coefficient of the coating solution at this time was 89 cm ^-1 .

Example 2 [Production method of coating solution] The intermediate layer coating solution obtained in Example 1 and the heat-sensitive coating solution (1) obtained in Example 1 were diluted with water to a concentration of 35% by adding water. The heat-sensitive coating solution was used. At this time, the extinction coefficient of the heat-sensitive coating solution was 240 cm ^-1 .

[Applying Method] After applying the intermediate layer in the same manner as in Example 1, the curtain weight was set to 40 using a curtain coating apparatus provided with an induction heating type application amount profile control mechanism.
In g / m ² of coating speed to high-quality paper 800 m / min, so that the amount of applying the coating solution is 4g / m ² 100,000
m is continuously applied and dried to obtain a winding length of 10,000.
Ten rolls of a 0 m thermosensitive recording sheet were obtained.

Comparative Example 1 [Production method of coating solution] Water was added to the intermediate layer coating solution obtained in Example 1 and the heat-sensitive coating solution (1) obtained in Example 1 to dilute the concentration to 9%. A heat-sensitive coating solution was used. The extinction coefficient of the heat-sensitive coating solution at this time was 71 cm ^-1 .

[Coating Method] After the intermediate layer was coated in the same manner as in Example 1, the curtain weight was set to 40 by using a curtain coating apparatus equipped with an induction heating type coating amount profile control mechanism.
at a coating speed of 400 meters / min on a high-quality paper g / m ^2, so that the amount of applying the coating solution is 4g / m ^2, 100,00
0 m length is continuously applied and dried, and the winding length is 10.0
Ten rolls of a 00 m thermosensitive recording sheet were obtained.

Comparative Example 2 [Production method of coating liquid] The coating liquid for the intermediate layer and the heat-sensitive coating liquid (1) obtained in Example 1 were used as they were. At this time, the extinction coefficient of the heat-sensitive coating solution (1) was 262 cm ^-1 .

[Coating Method] After the intermediate layer was coated in the same manner as in Example 1, the curtain weight was set to 40 using a curtain coating apparatus equipped with an induction heating type coating amount profile control mechanism.
at a coating speed of 800 m / min on a high-quality paper g / m ^2, so that the amount of applying the coating solution is 4g / m ^2, 100,00
0 m length is continuously applied and dried, and the winding length is 10.0
Ten rolls of a 00 m thermosensitive recording sheet were obtained.

Comparative Example 3 [Production Method of Coating Liquid] Water was added to the intermediate layer coating liquid obtained in Example 1 and the heat-sensitive coating liquid (1) obtained in Example 1 to dilute the concentration to 35%. A heat-sensitive coating solution was used. The extinction coefficient of the coating solution at this time was 240 cm ^-1 .

[Coating Method] After applying the intermediate layer in the same manner as in Example 1, a curtain provided with a coating amount profile control mechanism using a hydraulic cylinder in place of the induction heating type coating amount profile control mechanism is used. Using a coating device,
At a coating speed of 800 m / min on a high-quality paper having a basis weight of 40 g / m ^2, so that the amount of applying the coating solution is 4g / m ^2, 10
A length of 10,000 m was continuously applied and dried to obtain ten rolls of a 10,000 m long thermosensitive recording sheet.

Comparative Example 4 [Production Method of Coating Solution] Water was added to the intermediate layer coating solution obtained in Example 1 and the heat-sensitive coating solution (1) obtained in Example 1 to dilute the concentration to 35%. A heat-sensitive coating solution was used. The extinction coefficient of the coating solution at this time was 240 cm ^-1 .

[Coating Method] After applying the intermediate layer in the same manner as in Example 1, using a curtain coating apparatus without a coating amount profile control mechanism, 800 m / m ² of high quality paper having a basis weight of 40 g / m ² was used. At a coating speed of min, the coating liquid is continuously applied to a length of 100,000 m so that the coating amount becomes 4 g / m ² , and dried, and a thermosensitive recording sheet having a winding length of 10,000 m is wound up. Ten were obtained.

Comparative Example 5 [Production Method of Coating Solution] Water was added to the intermediate layer coating solution obtained in Example 1 and the heat-sensitive coating solution (1) obtained in Example 1 to dilute the concentration to 22%. A heat-sensitive coating solution was used. At this time, the extinction coefficient of the coating solution was 164 cm ^-1 .

[Applying Method] After applying the intermediate layer in the same manner as in Example 1, using an air knife applicator, the coating solution was applied to high quality paper having a basis weight of 40 g / m ² at an application speed of 350 m / min. So that the coating amount is 4 g / m ^2.
A length of 10,000 m was continuously applied and dried to obtain ten rolls of a 10,000 m long thermosensitive recording sheet.

Comparative Example 6 [Production Method of Coating Solution] With the coating solution for the intermediate layer obtained in Example 1. Water was added to the heat-sensitive coating solution (1) to dilute the concentration to 35% to use the heat-sensitive coating solution. The extinction coefficient of the coating solution at this time was 240 cm ^-1 .

[Applying Method] After applying the intermediate layer in the same manner as in Example 1, the basis weight was calculated using a blade applying apparatus.
0 g / m ² high quality paper at an application speed of 800 m / min,
100, 0, 100 g of the coating solution is applied so that the coating amount is 4 g / m ²
00 m length is continuously applied and dried to obtain a winding length of 10,
Ten 000 m of heat-sensitive recording sheets were obtained.

<Evaluation Method 1 for Thermosensitive Recording Sheet> With respect to all of the obtained ten windings, the occurrence of irregularities due to the winding shape and uneven coating was observed. In the case where the winding shape is not generated in the application unevenness in all the ten windings, ◎, when the minute distortion of the winding shape is generated in one or two of the ten windings,
、: When clear application unevenness occurred even at one place, Δ was determined, and when clear application unevenness occurred at two or more places, X was determined. Here, Δ and × cannot be practically used as products.

<Evaluation Method 2 for Thermal Recording Sheet> The evaluation of the coated surface quality was performed by setting an arbitrary part of the winding to 30 c in the flow direction.
m, a sample was taken in the entire width in the width direction, and visually determined. When the coating surface is uniform on all coating surfaces, ◎, when almost good, ○, when there is slight unevenness, △,
When unevenness was conspicuous, it was judged as x.

<Evaluation method 3 for heat-sensitive recording sheet>
Processing was performed for 400 seconds, and the recording density was evaluated using a G3 FAX tester. Here, the recording density does not directly correspond to the sensitivity of the thermal paper, but indicates the proportion of the component which effectively contributes to the color development in the thermal coating layer when the solid content is the same. That is, when the coating amount is the same, if the color density is high, the concentration of the component contributing to color development on the surface of the coating layer is high, and the sensitivity is also high. The tester used was a thermal head having a dot density of 8 dots / mm and a head resistance of 1045Ω manufactured by Okura Electric (TH-PMD), and printing was performed at a head voltage of 20 V and a power-on time of 1.2 ms, and Macbeth RD-918. Was measured with a reflection densitometer.

Table 1 shows the production process and the evaluation results of the samples for the heat-sensitive recording sheets prepared as Examples and Comparative Examples as described above.

<Evaluation Results> Although the evaluation results as shown in Table 1 were obtained, the extinction coefficient of the coating liquid was 8 using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism.
In the case of 9, 240 cm ^-1 , the recording density, coating surface quality, and winding shape are all good. However, using an application amount profile controller, the extinction coefficient is 71, 262 cm.
^{When the value} is ^-1 and when the application amount profile control device is not provided, the recording density and the application surface quality are good, but the winding shape is uneven. When a hydraulic cylinder is used for the application amount profile control mechanism, the recording density and the application surface quality are good, but the winding shape is inferior to that of the induction heating type. When a blade or an air knife coating device is used, there is no problem in the shape of the wound, but it is inferior to a heat-sensitive recording sheet coated with a curtain coating device in color development and stain resistance.

[0126]

[Table 1]

Example 3 [Production Method of Coating Solution] <Capsule Dispersion> 200 parts of high boiling oil (KMC-113 manufactured by Kureha Chemical Co., Ltd.) in which 5 parts of crystal violet lactone (CVL) were dissolved was mixed with 5% styrene. It is added to 250 parts of a maleic anhydride copolymer aqueous solution (PH 5.0),
The emulsion was emulsified so as to have an average particle size of 6 μm.

Next, 20 parts of a 40% aqueous solution of a melamine-formalin precondensate (Sumitetsu Chemical Co., Ltd. Sumiretz Resin) was added to the above emulsion, the temperature was raised to 75 ° C., and the mixture was reacted for 2 hours. PH = 9 with aqueous sodium oxide solution.
After cooling to room temperature as 0, a 40% microcapsule dispersion was obtained.

<Coating Liquid> The microcapsule dispersion liquid thus obtained was further adjusted to a solid content of 42% by adding water to the following composition to obtain a coating liquid (2). 40% microcapsule dispersion: 100 parts Wheat starch (average particle size: 20 μm): 50 parts 48% carboxy-modified styrene-butadiene copolymer latex: 20 parts

[Coating Method] Using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism, water was applied to the coating liquid (2) at a coating speed of 200 m / min on high-quality paper having a basis weight of 40 g / m ^2. To a concentration of 11%,
A length of 100,000 m was continuously applied so that the coating amount was 4 g / m ² , and dried to obtain ten rolls of a pressure-sensitive copying sheet having a length of 10,000 m. The extinction coefficient of the coating solution at this time was 94 cm ^-1 .

Example 4 [Production method of coating liquid] The coating liquid (2) obtained in Example 3
Was added to water and diluted to 37% to obtain a coating solution. The extinction coefficient of the coating solution at this time was 226 cm ^-1 .

[Coating Method] Using a curtain coating apparatus equipped with an induction heating type coating amount profile control mechanism, the coating amount of the coating solution was 4 g at a coating speed of 800 m / min on a high-quality paper having a basis weight of 40 g / m ^2. / M ² to 100,
000 m length is continuously applied and dried, and the roll length is 1
Ten rolls of a 000 m pressure-sensitive copying sheet were obtained.

Comparative Example 7 [Production method of coating liquid] The coating liquid (2) obtained in Example 3
Was added to water and diluted to 9% to obtain a coating solution. At this time, the extinction coefficient of the coating solution was 70 cm ^-1 .

[Coating Method] Using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism, a coating amount of the coating solution was 4 g at a coating speed of 200 m / min on a high-quality paper having a basis weight of 40 g / m ^2. / M ² to 100,
000 m length is continuously applied and dried, and the roll length is 1
Ten rolls of a 000 m pressure-sensitive copying sheet were obtained.

Comparative Example 8 [Production method of coating liquid] The coating liquid (2) of 42% obtained in Example 3 was used as a coating liquid as it was. At this time, the extinction coefficient of the coating solution was 259 cm ^-1 .

[Coating Method] Using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism, a coating amount of 4 g of the coating liquid was applied to a high quality paper of 40 g / m ² at an application speed of 800 m / min. / M ² to 100,
000 m length is continuously applied and dried, and the roll length is 1
Ten rolls of a 000 m pressure-sensitive copying sheet were obtained.

Comparative Example 3 [Production method of coating solution] The coating solution (2) obtained in Example 3
Was added to water and diluted to 37% to obtain a coating solution. The extinction coefficient of the coating solution at this time was 226 cm ^-1 .

[Coating Method] Instead of the induction heating type profile control mechanism, a curtain coating apparatus provided with a coating amount profile control mechanism using a hydraulic cylinder was used to apply 800 m / min to high quality paper having a basis weight of 40 g / m ^2. At a speed, apply the coating solution to 100, so that the coating amount is 4 g / m ² .
000 m length is continuously applied and dried, and the roll length is 1
Ten rolls of a 000 m pressure-sensitive copying sheet were obtained.

Comparative Example 10 [Production method of coating liquid] The coating liquid (2) obtained in Example 3
Was added to water and diluted to 37% to obtain a coating solution. The extinction coefficient of the coating solution at this time was 226 cm ^-1 .

[Coating Method] Using a curtain coating apparatus without a coating amount profile control mechanism, a basis weight of 40 g / m
At a coating speed of 800 m / min to ² fine paper, the amount of applying the coating solution is continuously applied to the length of 100,000m to be 4g / m ^2, and dried, the Makicho of 10,000m 10 rolls of pressure-sensitive copying sheet were obtained.

Comparative Example 11 [Production method of coating liquid] The coating liquid (2) obtained in Example 3
Was added to water and diluted to 22% to obtain a coating solution. The extinction coefficient of the coating solution at this time was 171 cm ^-1 .

[Coating Method] Using an air knife coating device,
The coating liquid is continuously applied to a high quality paper having a basis weight of 40 g / m ² at a coating speed of 500 m / min to a length of 100,000 m so that the coating amount becomes 4 g / m ² in a completely dry state, and then dried. Then, ten rolls of a pressure-sensitive copying sheet having a winding length of 10,000 m were obtained.

Comparative Example 12 [Production method of coating liquid] The coating liquid (2) obtained in Example 3
Was added to water and diluted to 37% to obtain a coating solution. The extinction coefficient of the coating solution at this time was 226 cm ^-1 .

[Coating method] Using a blade coating device, apply the coating solution to a high quality paper of 40 g / m ² at a coating speed of 800 m / min so that the coating amount becomes 4 g / m ² in a completely dry state.
A length of 00,000 m was continuously applied and dried to obtain 10 rolls of a 10,000 m long pressure-sensitive copying sheet.

<Evaluation Method 1 for Rolling-Up of Pressure-Sensitive Copy Sheet> With respect to all of the obtained 10 rolls, the occurrence of irregularities due to the winding shape and uneven coating was observed.巻: When the winding shape and coating unevenness did not occur in all 10 windings, 、: When a minute distortion of the winding shape occurred in 1 to 2 out of 10 windings, ○: Clear coating unevenness was 1 It was determined to be Δ when there was also a spot, and x when there were two or more clear coating irregularities. Here, Δ and × cannot be practically used as products.

<Pressure Sensitive Copy Sheet Evaluation Method 2>
The color was developed by passing through a super calender in combination with 0), and the color development was evaluated. Good color development was evaluated as ○, slightly poor one as Δ, and poor one as X.

<Pressure-sensitive copy sheet evaluation method 3> 35 cm long
The above-mentioned lower paper of width 25 cm is combined with a coloring agent sheet of length 15 cm x width 15 cm, and a weight for evaluation of stain resistance of 3500 g is placed thereon, and the resistance to the stain is determined according to the degree of dirt when the coloring agent sheet is pulled at a constant speed. The contamination was evaluated, and those with no generation of dirt were evaluated as ○.
Δ: The occurrence was remarkable as x.

Table 2 shows the evaluation results of the pressure-sensitive copying sheets prepared as Examples and Comparative Examples as described above.

<Evaluation Results> Although the evaluation results as shown in Table 2 were obtained, the extinction coefficient of the coating solution was 9 using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism.
In the case of 4,226 cm ^-1 , color development, stain resistance, and wound shape are all good. However, using an application amount profile controller, the extinction coefficient is 70, 259 cm ^-1.
In the case of and the case where the application amount profile control device is not provided, the coloring property and the stain resistance are good, but the winding shape is uneven. When a hydraulic cylinder is used for the application amount profile control mechanism, the coloring property and the stain resistance are good, but the winding shape is inferior to that of the induction heating type. With a blade and air knife coating device,
Although there is no problem in the shape of the winding, it is inferior to the pressure-sensitive copying sheet applied by a curtain coating apparatus in color development and stain resistance.

[0150]

[Table 2]

Example 5 A coating solution having a solid content concentration of 58% and a solid content of the following composition was applied to a high-quality paper having a basis weight of 60 g / m ² by a curtain coating apparatus so that the absolute dry coating amount was 10 g / m ^2. , As undercoat liquid,
The coating was performed at a coating speed of 1000 m / min to prepare an undercoat base paper.

<Composition of undercoat liquid>-Commercial heavy calcium carbonate (Carbital 90): 70 parts-Commercial secondary kaolin (caobrite): 30 parts-Commercial polyacrylic acid-based dispersant: 0.2 parts-Commercial phosphoric ester Modified starch: 9 parts Styrene butadiene latex: 8 parts Sodium hydroxide: 0.1 part

With the following composition, an overcoating liquid (3) having a solid content of 60% was prepared. Using a curtain coating apparatus equipped with an induction heating type coating amount profile control mechanism, water was added to the top coating liquid (3) at a coating speed of 400 m / min and diluted to 34% with a coating speed of 400 m / min. 10 g of the top coating solution is applied so that the coating amount is 4 g / m ^2.
A length of 10,000 m was continuously applied and dried to obtain 10 rolls of a 10,000 m-long pigment-coated paper. At this time, the extinction coefficient of the overcoating solution was 97 cm ^-1 .

<Composition of overcoat liquid>-Commercial heavy calcium carbonate (Carbital 90): 10 parts-Commercial primary kaolin (Ultra White 90): 50 parts-Commercial secondary kaolin (caobrite): 20 parts-Commercial cubic Light calcium carbonate (Brilliant 1
5): 10 parts ・ Aragonite-type calcium carbonate (HGA): 10
Parts-Commercially available polyacrylic acid-based dispersant: 0.2 parts-Commercially available phosphorylated starch: 3 parts-Styrene butadiene latex: 16 parts

Example 6 [Production method of coating liquid] Water was added to the top coating liquid (3) obtained in Example 5 to make a concentration of 53%. The extinction coefficient of the overcoat solution was 234 cm ^-1 .

[Coating Method] Using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism, a coating speed of 800 m / min was applied to the undercoated base paper obtained earlier.
A 100,000 m length of the top coating solution (5) is continuously applied so that the application amount is 12 g / m ² , and then dried.
Thus, 10 rolls of a pigment-coated paper having a roll length of 10,000 m were obtained.

Comparative Example 13 [Production Method of Coating Liquid] Water was added to the top coating liquid (3) obtained in Example 5 to make a 27% concentration of the top coating liquid. The extinction coefficient of the overcoat liquid was 69 cm ^-1 .

[Coating Method] Using a curtain coating device provided with an induction heating type coating amount profile control mechanism, the undercoating base paper previously obtained was coated at a coating speed of 400 m / min.
Apply the top coating solution so that the coating amount is 12 g / m ^2.
A length of 10,000 m was continuously applied and dried to obtain 10 rolls of a pigment-coated paper having a length of 10,000 m.

Comparative Example 14 [Production Method of Coating Liquid] The top coating liquid (3) having a concentration of 60% obtained in Example 5 was used as it was. The extinction coefficient of the overcoat solution was 267 cm ^-1 .

[Coating Method] Using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism, a coating speed of 400 m / min was applied to the undercoated base paper obtained earlier.
Continuously apply the top coat coating liquid (3) to a length of 100,000 m so that the coating amount becomes 12 g / m ² , and then dry, and take up 10 rolls of a 10,000 m long pigment coated paper. I got

Comparative Example 15 [Production Method of Coating Liquid] Water was added to the top coating liquid (3) obtained in Example 5 to make a concentration of 53%. The extinction coefficient of the overcoat solution was 234 cm ^-1 .

[Coating Method] Instead of the induction heating type profile control mechanism, a curtain coating apparatus provided with a coating amount profile control mechanism using a hydraulic cylinder was used, and a coating speed of 800 m / min was applied to the undercoat base paper obtained earlier. ,
Apply the top coating solution so that the coating amount is 12 g / m ^2.
A length of 10,000 m was continuously applied and dried to obtain 10 rolls of a 10,000 m-long pigment-coated paper.

Comparative Example 16 [Production method of coating solution] Water was added to the top coating solution (3) obtained in Example 5 to make a concentration of 53%, and a top coating solution was used. The extinction coefficient of the overcoat solution was 234 cm ^-1 .

[Coating Method] Using a curtain coating device without a coating amount profile control mechanism, the coating amount of the top coating liquid is 12 g / m ² at a coating speed of 800 m / min on the base paper obtained earlier. Like 100,000
m is continuously applied and dried to obtain a winding length of 10,000.
10 rolls of 0 m pigment coated paper were obtained.

Comparative Example 17 [Production method of coating solution] Water was added to the top coating solution (3) having a concentration of 60% obtained in Example 5 to obtain a top coating solution having a concentration of 44%. The extinction coefficient of the top coating liquid is 148
cm ^-1 .

[Coating Method] Using an air knife coating device,
At a coating speed of 400 m / min, a 100,000 m length of the top coating liquid was continuously applied to the undercoated base paper obtained previously so that the coating amount was 12 g / m ² , and dried.
Ten rolls of pigment-coated paper with a length of 10,000 m were obtained.

Comparative Example 18 [Production method of coating solution] Water was added to the top coating solution (3) obtained in Example 5 to make the concentration of 53%. The extinction coefficient of the overcoat solution was 234 cm ^-1 .

[0168] Using the coating method] blade coating apparatus at coating speed of 800 m / min in the undercoat base paper previously obtained, the overcoat coating solution so that the amount of coating is 12 g / m ² of 100, 0 00m long Is applied continuously and dried,
Ten rolls of pigment-coated paper with a length of 10,000 m were obtained.

<Evaluation Method 1 for Rolling Pigment-Coated Paper> With respect to all of the obtained 10 windings, the state of the occurrence of irregularities due to the winding shape and uneven coating was observed. In the case where the winding shape is not generated in the application unevenness in all the ten windings, ◎, when the minute distortion of the winding shape is generated in one or two of the ten windings,
、: When clear application unevenness occurred even at one place, Δ was determined, and when clear application unevenness occurred at two or more places, X was determined. Here, Δ and × cannot be practically used as products.

<Evaluation Method 2 for Pigment-Coated Paper> The smoothness of the coated layer was measured by a smoother smoothness tester (model SM-6A, manufactured by Toei Electronics Co., Ltd.). (Unit: mm
Hg)

<Evaluation Method 3 for Pigment-Coated Paper> The printing unevenness was evaluated by printing with a Roland offset printing machine under the condition that the dampening water was excessively supplied with water, and allowed to stand at room temperature for 24 hours. The printing was performed visually with respect to a printed portion having an area ratio of halftone dots of 50%. (Unit: 5 out of 5)

<Evaluation Method 4 for Pigment-Coated Paper> The coating surface quality was evaluated by visually observing a sample at an arbitrary portion of the winding in a direction of 30 cm in the flow direction and a full width in the width direction.
When the coating surface quality was completely uniform, it was judged as ◎, when almost good, ○, when there was slight unevenness, Δ, and when unevenness was conspicuous, ×.

Table 3 shows the evaluation results of the pigment coated papers prepared as Examples and Comparative Examples as described above.

<Evaluation Results> Although the evaluation results as shown in Table 3 were obtained, the extinction coefficient of the coating solution was 9 using a curtain coating apparatus provided with an induction heating type coating amount profile control mechanism.
In the case of 7,234 cm ^-1 , the coloring property, the stain resistance and the winding shape are all good. However, using an application amount profile controller, the extinction coefficient was 69, 267 cm ^-1.
In the case of and the case where the application amount profile control device is not provided, the smoothness, the printing unevenness, and the coating surface quality are good, but the winding shape is uneven. When a hydraulic cylinder is used for the coating amount profile control mechanism, smoothness, printing unevenness, and coating surface quality are good, but the winding shape is inferior to that of the induction heating type. When using a blade and air knife coating device, there is no problem with the winding shape,
Inferior to pigment-coated paper coated with a curtain coating device in smoothness, printing unevenness and coated surface quality.

[0175]

[Table 3]

[0176]

According to the present invention, the following novel effects can be obtained.

By applying a curtain coating device provided with a profile control mechanism to the application of a heat-sensitive coating solution, a high-quality heat-sensitive recording sheet having excellent sensitivity can be obtained.

By applying the present invention to the application of a coating solution containing microcapsules as a main component, a high-quality pressure-sensitive copying sheet having excellent coloring and stain resistance can be obtained.

By applying to the application of the pigment coating solution,
It is possible to obtain a high quality pigment coated paper excellent in smoothness, printing unevenness, and coated surface quality.

By applying a curtain coating device provided with a profile control mechanism to the application of a coating liquid, uniform coating can always be performed even when a large amount of product is applied over a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic view of a curtain film thickness profile measuring apparatus showing one embodiment of the present invention.

FIG. 2 is a schematic view of a curtain film thickness profile measuring apparatus showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a coater head provided with a profile and adjustment mechanism according to the present invention.

FIG. 4 is a schematic view of a coating apparatus showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coater head 2 Curtain film 3 Light source part 4 Light receiving part 5 Computer 6 Moving stage 7 Profile adjustment device 8 Profile adjustment device power supply controller 9 Liquid supply tank 10 Web 11a, 11b Edge guide 12 Roll 13 Liquid receiving tank 14 Wind shield plate 15 Supply Liquid pump 16 Profile plate 17 Insulation material 18a, 18b Coil 19 Profile adjustment block

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁷ Identification code FI D21H 23/48 G11B 5/842 27/00 B41M 5/12 112 G11B 5/842 5/18 104 108 (58) Fields surveyed ( Int.Cl. ⁷ , DB name) B05D 7 / 00,1 / 30 B05C 5/00 103 B05C 5/02 B41M 5 / 165,5 / 30 D21H 23 / 48,27 / 00 G11B 5/842

Claims (5)

(57) [Claims] In a method of manufacturing a coated paper by applying a coating liquid, a curtain film thickness profile is optically measured in a width direction, and the measured value is converted into a flow rate value. are those using curtain coating apparatus attached a mechanism for controlling the slit opening, and Sri
Controls the opening of the curtain and the voltage of the thickness profile of the curtain film
Value or current value, and the metal mass in contact with the coater head
Is heated to cause thermal expansion of the metal lump and the slit is opened.
A method for producing a coated paper, wherein the method is performed by changing the degree . 2. A curtain film thickness profile measurements, indicated by optical density gradation G _B of the optical density gradation G and the blank exposure of the curtain film in the following Equation 1, and the absorption coefficient a, 80
2. The method for producing a coated paper according to claim 1, wherein the thickness is in the range of ~ 250. [Number 1] x = - (1 / a) · ln (G / G B) ( Equation 1) x: Curtain thickness a: extinction coefficient (cm ^-1) G: Optical curtain film density gradation G _B: Optical density gradation of blank exposure 3. A color former and claim 1 or 2 heat-sensitive recording sheet manufacturing method according to the coating solution formed by coating mainly containing developer. 4. The process for producing pressure-sensitive copying sheets one surface formed by coating a coating solution mainly composed of microcapsules according to claim 1 or 2, wherein the support. 5. A pigment formed by coating a coating solution mainly composed of claim 1 or 2 pigment coated paper manufacturing method according.