JP3058482B2 - Manufacturing method of continuous slip paper and continuous slip 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 continuous slip paper having a high bulkiness, high rigidity, high tensile strength and excellent printing surface strength when finishing to a predetermined static smoothness in the production of continuous slip paper. The present invention relates to a continuous slip sheet manufactured by a manufacturing method.

[0002]

2. Description of the Related Art In recent years, with the remarkable progress of the advanced information society, the demand for paper used in information processing equipment such as copying machines, office automation equipment, and new media equipment has been steadily increasing. Among them, continuous slip paper is generally used mainly as output paper for computers. This is usually printed and processed by a form printing machine, and is commercialized as a continuous slip sheet having perforations and feed holes.

[0003] The characteristics required for a continuous slip sheet are generally as follows.

(1) Since the form is formed from the winding, the uniformity of the paper quality in the width direction is good, and the winding characteristic is free from trouble such as one-sided stretching and meandering during the processing.

(2) Printability with high surface strength and little paper dust trouble.

(3) The wear of the blades during marginal punching and perforation processing is small.

[0007] In particular, a problem in printability relates to print quality and workability. If the surface strength of the paper is low, paper curl occurs, which stains the blanket or plate of the printing press and causes white spots to deteriorate the print quality. In addition, when paper dust is generated due to a slit defect, blanket contamination is also caused. In order to prevent these, measures for increasing the surface strength (changing pulp beating conditions, adding chemicals) are generally performed.

For example, white spots on high quality paper are mainly caused by vessels (vessels), and others are caused by fibers and fillers. The mechanism is that the weakly bonded vessel present on the paper surface is peeled off by the ink tack at the time of printing, and then transferred and deposited on a blanket or plate.After a certain number of prints, the vessel receives dampening water. , And the ink does not get on, resulting in white spots. Since the vessel is peeled off at a certain probability in proportion to the surface strength of the paper, paper makers control the quality by strengthening the beating or applying a chemical such as starch to the paper surface by a size press.

As described above, various measures have been taken to increase the surface strength of paper. However, since the calender part crushes the paper at a certain pressure in the paper making process, it generally tends to cut off the inter-fiber bonds and reduce the surface strength. is there. In particular, the higher the pressure and the lower the moisture content, the higher the tendency.
Further, as the calendering process is performed at a lower temperature, a stronger linear pressure is required to finish the paper with a predetermined surface property, and as a result, the surface strength is reduced.

From such a viewpoint, as a more preferable calendering method, a method of applying heat to the paper surface or applying heated steam to the paper surface immediately before calendering or calendering with a high-temperature roll can be considered.

Generally, in order to improve the surface properties of paper,
It is said that humidification is more effective than heating (MA)
groups; Tappi J .; 66 (10), 96
(1983)). Accordingly, it is considered that calendering by humidification is more advantageous for maintaining the surface strength because calendering by humidification than low calendering can be performed at a low linear pressure if the paper is finished with the same surface properties. In the case of humidification by water application, the average moisture of the paper increases by at least about 1.5%,
There is a problem that the increase in the density becomes too large, and that excessive humidification also causes a problem that paper powder adheres to the calender roll. Therefore, it is considered that it is most preferable to carry out calendering using heated steam that has both heating and humidifying effects on the paper.

As described above, a method of calendering after applying mild heating steam to paper has been recently developed, and its effect has been recognized (JP-A-2-160993). However, this is applied to coated lightweight general printing paper,
It is not intended for information recording paper as in the present invention.
In addition, the present invention is basically different from the present invention in the following points.

(1) The continuous slip paper used in the present invention naturally has a different surface property because the coating liquid is not applied on the paper. Therefore, when steam humidification is performed, the plasticity of the paper surface against moisture and heat is different.

(2) In the present invention, the calendering conditions after steam is applied to the paper are limited to the processing temperature of 100 to 150 ° C. as described in the above claims. It is recognized that the same effect can be obtained (the same effect cannot be obtained by the method disclosed in JP-A-2-160993).

Further, calendering under the above-mentioned high-temperature condition is possible only by using a soft calender having a special resin roll having high heat resistance. The soft calender method is basically a combination of a metal roll and a soft roll on-machine (sometimes off-machine) and calendering with a small number of nips. This is a method in which a metal roll is used as a humidifying type using a roll that has been made.

[0016]

The present inventors have conducted intensive studies to solve the problem of the printing surface strength of the continuous chit paper as described above. After heating the paper surface with low pressure and mild heating steam,
It is intended to provide a method for producing a continuous slip sheet having excellent printing surface strength by performing a soft calendering treatment in a range of 0 ° C., and a continuous slip sheet obtained by the manufacturing method.

[0017]

According to the present invention, in a method for producing continuous slip paper, a low-pressure, mild heating steam is jetted in parallel to the paper just before calendering to humidify and heat the paper surface, and then the paper is heated to 100 to 150 mm. A production method characterized by performing a soft calender treatment within a temperature range of ° C. The present invention also relates to a continuous slip sheet obtained by the above manufacturing method, and further includes a smoothness (JAPAN) after calendar processing.
Tappi No5 Oken type smoothness tester measurement value)
A continuous slip sheet in the range of 20 to 70 seconds is typical.

A feature of the present invention resides in that low-pressure, mild heating steam is adhered to the paper surface under specific conditions immediately before calendering of continuous slip paper. However, the conventional steam humidifier is an actual machine. In the case of continuous use, there were the following problems.

That is, (1) the steam drain is dropped or blown off on the paper surface, and (2) the steam is scattered around, condensed on peripheral devices, and the dew water drops on the paper. (3) There is a problem that steam leaks to the surroundings and the working environment deteriorates.

In order to solve the above-mentioned problems, there has been proposed an apparatus which uses the Coanda effect to flow steam in parallel and opposite to paper. The advantages are that the contact time between the paper and the steam can be lengthened, the intrusion of the air mixed with the paper can be prevented, and the running stability of the paper is improved.

The main concept of the present apparatus is as follows.

The thermal energy of the steam is supplied by the steam that becomes fine particles and condenses on the paper surface due to the temperature difference between the paper and the steam. At this time, if air intervenes, the air acts as a heat insulating material, the efficiency of heat transfer is significantly reduced, and condensed water becomes large particles, and the adhesion of condensed water to paper becomes uneven. , Moisture and temperature unevenness increase. Thus, the use in front of the calendar became possible for the first time by solving the operational problems and improving the thermal efficiency.

Conventional calendering is performed at about 50 to 80 ° C.
The paper is crushed with a considerably high linear pressure in order to obtain a predetermined surface property. In order to obtain the same surface properties at a lower linear pressure and minimize the decrease in printing surface strength, it is necessary to improve the surface properties by densifying only a very surface layer of the paper. As this technique, a so-called temperature gradient calendering method in which only the surface layer of paper is crushed by heating to develop surface properties has been proposed (MF Gratton et. Al .; Pulp).
and Paper Can. 88 (12), T461
(1987), etc.).

Another method is to crush only the surface layer of paper by humidification. This method is basically the same as the temperature gradient calendar method only in the difference between heating and humidification. That is, it is a mechanism for transferring a calender roll surface to a plasticized paper surface by calendering immediately after plasticizing only the surface layer portion of the paper by humidification.

The present inventors have conducted extensive studies on this humidifying calendar method. As a result, when humidifying by a water shower, the amount of humidification increases (the average moisture content of paper is 1.5%).
% Or more), the surface properties are greatly improved by the calendering treatment, but at the same time, the increase in the density becomes too large to maintain the predetermined paper thickness. He acknowledged that there would be problems with the roll. It is considered that the moderate increase in density is caused by the penetration of moisture not only into the surface layer of the paper but also into the middle layer.

Further, this method has another problem that it is difficult to control the moisture profile of the paper. In this case, it was also found that water adhering to the paper surface lowered the temperature of the calender roll.

As described above, in order to plasticize the paper surface, it is desirable to treat the calender roll at a higher temperature. However, in the humidifying method using a water shower, the calender roll acts in the direction of lowering the calender roll temperature, so that the negative effect is obtained. It will be effective.

From the above studies, the present inventors have recognized that the humidification method using steam is the best. Since the steam used in the present invention has a high temperature (100 ° C. or higher), the paper surface is simultaneously humidified and heated to be plasticized. Therefore, when calendering is performed immediately after steam humidification, the density increases only in the surface layer of the paper and the surface properties are improved, but the density does not increase in the middle layer of the paper, and the average density does not increase so much for the entire paper, and the low line A predetermined surface property can be obtained by the pressure treatment, and a continuous slip sheet excellent in printing surface strength can be obtained.

Further, a prior art (Japanese Patent Laid-Open No. Hei.
1609993) is basically different in the following points. First, in the present invention, the calendering temperature after the steam is applied to the paper is set at a temperature of 100 to 150 ° C., as described in the claims.

According to the above prior art, the Oken-type smoothness can be improved by calendering by steam humidification while minimizing the increase in the density and the decrease in the bulk of the paper. It is argued that printability can be improved. However, according to the method of the present invention, as a condition for calendering after steam humidification, a calendering temperature is in a range of 100 to 150 ° C., and a soft calendering method having a high heat-resistant and pressure-resistant special resin roll as an apparatus is adopted. For the first time, it is possible to improve the printing surface strength of the continuous slip paper. In addition, this effect can be exerted without improving the Oken type smoothness.

Further, in the above prior art, the bulk (reciprocal of the density),
It was also recognized that the stiffness tends to decrease, while the method of the present invention can improve bulk and stiffness.

The reason for this is that the mechanism for developing the surface properties of the paper is influenced by complicated factors such as the heat and moisture plasticity of the paper, the thermal conductivity of the paper, the elastic modulus, the paper layer structure, and the elastic modulus of the elastic roll. I am not sure because it is thought to be done,
Generally, the following differences can be considered.

First, when the calendering treatment is performed at a temperature of 100 ° C. or less as described above, the temperature of the calender roll is lower than the temperature of the surface layer of the paper. This results in a negative effect on the effect of plasticizing only the surface layer of the paper. As a result, even if the paper is finished to the same density, the Oken type smoothness does not improve.

Further, if the treatment is carried out at a high temperature of 150 ° C. or more, the heating and the humidification by steam become excessive, and the surface properties are greatly improved by the synergistic effect, but the density is extremely increased as described above. As a result, the bulk and strength properties are reduced.

According to the method of the invention, in part, 100 ° C.
By performing the treatment at the above high temperature, the same Oken-type smoothness can be obtained, and the treatment can be performed at a low linear pressure.
Further, since it is not necessary to give a strong ironing to the paper, the tensile strength and the like are improved (there is no effect at 100 ° C. or lower).
The temperature of the roll of the soft calender is preferably set higher than the temperature of the paper.

The use of a soft calender made of a combination of a special resin roll and a metal roll excellent in heat resistance and pressure resistance makes it possible to carry out calendering at such a high temperature for the first time. Because, in the case of a commonly used super calender, the internal heat of the cotton roll, which is an elastic roll, is large and the heat resistance and pressure resistance are limited, so the maximum use temperature of the roll is generally limited to about 85 ° C or less. That is because In the case of a gloss calender generally used in the production of paperboard, the metal roll side is 1
Although it is used even at a high temperature of 00 ° C. or more, rubber rolls, which are elastic rolls, are extremely inferior in durability and cannot be generally applied to high-speed paper machines and high-speed coaters. Therefore, heat resistance,
Only when a soft calender with a special resin roll with excellent pressure resistance is adopted can it be used at high temperatures and high pressures.

As a device for jetting a low-pressure, mild heated steam stream to paper according to the present invention, a device for jetting steam in parallel with paper,
With a device that ejects a certain angle from the nozzle to the paper surface,
Any material can be used as long as it can be adjusted so that the vapor adheres to the paper surface and raises the temperature and moisture of the paper appropriately.

The steam used in the present invention is low-pressure, mild heating steam, and when applied to paper, the used steam pressure is 1 k
g / cm ² or less, and the steam flow rate is 15 to 80 kg / Hr /
It is desirable to apply steam within a width of m and a paper moisture increase rate of 0.3 to 1.2%. The reason is that as described above, if the vapor pressure is high and the flow rate is too high, excess water permeates into the middle layer of the paper, and the bulk after calendering treatment is greatly reduced. On the other hand, if the amount of steam adhering to the paper is too large, in the case of coated paper, there arises a problem that the surface of the coated layer is removed by a calender roll.
Conversely, if the steam flow rate is too low, there is a risk that the paper will have smoothness and uneven gloss, the effects of humidification and heating will be reduced, and the effects of improving smoothness and printability will also be reduced.

Therefore, as an appropriate condition for applying moisture, desirably, steam is applied within a paper moisture increase rate of 0.3 to 1.2%.

It is preferable that the time from the application of steam to the time when it enters the calender roll nip be as short as possible.
It is desirable to be within the range of 0.25 seconds. If the time is longer than this, vapor particles penetrate into the middle layer of the paper, and the bulk after calendering treatment is greatly reduced.

As a result of this study, it was found that the hardness of the elastic roll used was desirably in the range of Shore D 87-93.

Although the reason is not clear, when the hardness of the elastic roll is lower, the nip width becomes wider and the surface pressure on the paper becomes larger. In this case, the time required to transfer the surface of the metal roll to the paper surface is longer, and the linear pressure is smaller than the surface pressure, so that the glossiness of the paper is higher. Oken-type smoothness, which measures the smoothness near the part, does not appear as a significant improvement.

Conversely, when the elastic roll hardness is high, the nip width is narrow and the linear pressure applied to the paper is high, so that it is considered that the improvement in the smoothness of the Oken method is also large. However, if the roll hardness is excessively high, the roll will be damaged when foreign matter passes and its resilience will be poor, making it impractical.
The difference with the calendar method by the combination of the metal rolls disappears. Therefore, it is necessary to use an elastic roll having an appropriate hardness range.

The continuous slip sheet of the present invention has a basis weight of 40.
It is limited to the range of 150 to 150 g / m ² , and may be any of high-quality paper, medium-quality paper and those containing recycled waste paper.
In addition, the smoothness after calendar processing (JAPAN Tapp
i No5 Oken-type smoothness tester measured value) is 20-7
It is typically in the range of 0 seconds.

The filler internally added to the base paper may be any commonly used filler such as talc, clay, kaolin, calcium carbonate and the like.

Further, the continuous slip paper of the present invention contains, if necessary, additives usually used in papermaking, such as a dye, a sizing agent, a dry paper strength enhancer, a wet paper strength enhancer, a fixing agent and a retention aid. It is a thing.

As described above, the present inventors have conducted various studies on a calendering method by heating or humidification as a means for plasticizing only the surface layer of the paper. As a result, low-pressure, mild heating steam was applied to the surface of the continuous slip paper. After humidifying and heating the paper surface, by performing a soft calendering treatment within a temperature range of 100 to 150 ° C., it is possible to produce a continuous slip sheet having high bulk, high tensile strength, and excellent printing surface strength. recognized.

[0048]

An embodiment of the present invention will be described. For calendar processing,
Using a two-stack soft calender having a two-stage soft nip composed of a combination of a chill roll and a resin roll having a heating device, humidifying so that steam is blown out to the paper surface on the side that hits the chill roll before each nip. The apparatus (Steam Foil of Aikawa Iron Works Co., Ltd.) was installed, and the following experiment was performed.

The details of the soft calender used in this example and the comparative example are as follows.

Body maker: Minami-Senju Seisakusho Co., Ltd. Roll surface length: 1050 mm Heating roll: Induction heating jacket roll (manufactured by Tokuden) Soft roll: Eragrass RE (manufactured by Kyoyo) Shore hardness D89 Other Examples 1 Basis weight 64 g / m ² For the continuous slip form, use vapor pressure 0.8
The steam was applied under a constant condition of kg / cm ² and a steam flow rate of 50 kg / Hr / m width, and each calender treatment was performed after 0.03 seconds. At that time, the treatment was performed at a calender roll temperature of 120 ° C.

Comparative Example 1 A calender treatment was performed under the same conditions as in Example 1 except that the calender treatment was performed at a calender roll temperature of 70 ° C.

Comparative Example 2 The same continuous slip sheet as in Example 1 was used and calendered under the same conditions except that no steam was used.

(Quality evaluation method) Smoothness: Measured with a Japan Tappi No. 5 Oken type smoothness tester.

[0054] Printing surface strength: Using a Roland offset printing machine, the number of white spots on the solid portion and the halftone portion of the printed matter at the end of 2,000 printed sheets was counted and converted to the number per 250 cm ² .

Tensile strength: Measured with a JIS P-8114 Shopper type tester.

[0056]

[0057]

As is clear from the table, unlike the conventional steam humidifying calender technique, the calendering conditions after the steam is applied to the paper are set to the calendering temperature of 100 to 150 ° C. as described in the above claims. When the paper is finished to a predetermined Oken type smoothness by the method of the present invention which is defined and soft calendered, it is bulky, strength characteristics are improved, and printing surface strength (printing white point) can be dramatically improved. Can be.

Therefore, continuous slip paper manufactured by the method for manufacturing continuous slip paper according to the present invention has excellent quality characteristics which have not been obtained in the past, and its product value is extremely large.

Continued on the front page (72) Inventor Yoshifumi Iimori 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Sanyo Kokusaku Pulp Co., Ltd. Product Development Laboratory (72) Inventor Toshio Inoue 2-8-8 Iidacho, Iwakuni-shi, Yamaguchi Prefecture No. 1 Sanyo Kokusaku Pulp Co., Ltd. Production Technology Research Laboratory (56) References JP-A-62-177277 (JP, A) JP-A-2-160993 (JP, A) JP-A-2-242994 (JP, A) JP-A-4-361686 (JP, A) JP-A-4-361695 (JP, A) JP-B-47-38882 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B42D 15/04-15/08 D21G 1/00

Claims (3)

(57) [Claims] In a method for producing a continuous slip sheet, immediately before soft calendering of the continuous slip sheet, a low-pressure light heating steam is applied to humidify and heat the paper surface, and then the temperature of the calender roll is set to 100 to 150 ° C. A method for producing continuous slip paper, wherein soft calendar processing is performed within the range of (1). 2. A continuous slip sheet produced by the method according to claim 1. 3. Smoothness after calendar processing (JAPAN
Tappi No5 Oken type smoothness tester measured value)
3. The continuous slip sheet according to claim 2, wherein the length is in the range of 20 to 70 seconds.