JP2006508267A - LWC paper product and its manufacturing method - Google Patents

Abstract

A coated printing paper product, the production of which is realized by using a surface conditioning device after the coating process, the surface conditioning device having a fixed support member and a paper web running between the jacket and the counter roll And a flexible jacket provided around the fixed support member. The load member is provided in relation to the support member such that the flexible jacket is pressed by the load member toward the heatable counter roll. The coated product has a PPS-s10 roughness (ISO 8791-4) of 0.7-1.5 μm Hunter Gloss (ISO / DIS8254) of 30-80% as the surface properties of the upper surface of the paper, 1.15-1. It has a volume in the range of ³ m ³ / g.

Description

Detailed Description of the Invention

  The present invention relates to an LWC paper product and a method for producing the same.

  The object of the present invention is to improve the quality of paper products, in particular LWC paper products, and the economics of their production.

  The paper is required to have a certain surface quality to ensure the desired gloss and print quality, and low transparency, stiffness and durability. Furthermore, since paper is mass-produced in a paper mill, efficient use of raw materials is also important. These demands are somewhat contradictory. The paper can be given sufficient gloss by calendering the paper, often wetted or heated in some manner and pressed in the nip. The paper surface fibers and the coating are preferably pressed smoothly by this pressing without compressing the paper interlayer. Intermediate ply compression reduces stiffness and reduces durability. Compression of the intermediate layer is often referred to as bulk loss. In this case, bulk is understood as the reciprocal of density, and its loss is therefore equal to the densification compression of paper or paperboard.

  Since the paper production process is very expensive and raw material intensive, even small savings in raw materials offer significant advantages over competitors. In this regard, the 1% savings can be regarded as a significant competitive advantage and the return on investment is reduced. Saving raw materials is also desirable for environmental reasons. Thanks to the low weight paper grade, the multiple effects of the paper of the present invention cover the entire life of the product and ultimately save on transportation by reducing raw material consumption resulting in lighter packaging Birth and garbage will be reduced.

  The improved bulk and opacity does not cause any practical disadvantage to the consumer.

  Machine calendars are often used with other calendars to refer to a hard calendar with an inelastic roll. The use of a machine calendar as the only surface treatment method is not recommended. Soft calenders, also called soft nip calenders, have a surface on which the calender roll has elasticity, which can have the same order of hardness as the surface hardness of wood, but is still elastic.

  It is an object of the present invention to provide a flat printing surface, high gloss and rigidity on a printing paper with a smaller amount of material than before, and to avoid obstacles (bottleneck) and to run with the method of the present invention. It is to improve. Generally, the pre-processing of the paper surface prior to the coating process is performed with a machine calendar, and the final process is performed with a super calendar. The function of the machine calendar is to give the web a uniform thickness characteristic. After processing by the machine calendar, the paper is coated (coating) and the final calendar processing is typically performed by a super calendar. The coating method is typically blade coating or film coating.

The quality value of the offset LWC printing paper manufactured in this way is within the following range.
Bulk 0.90-1.1cm ³ / g
PPS-s10 Roughness 0.8-1.6μm
Gloss 50-70%
According to the present invention, the printing paper is processed with a long nip calender after the coating process in order to improve the paper quality compared with the conventional one, and further, the production operability is improved, and this production method is the same as the super calender. Is not limited by speed. A long nip calendar suitable for producing the paper of the present invention is disclosed, for example, in the earlier patent US6164198 by the applicant.

  The printing paper product of the present invention is characterized by what is given in the features of claim 1.

  A calendar suitable for the surface treatment of paper of the present invention comprises a fixed support member around which a tubular jacket is placed. A heated counter (counter) member is placed on the other side of the tubular jacket support member to allow the web to pass between the counter member and the tubular jacket. The fixed support member includes a load member, and presses the jacket against the heating facing member, thereby enabling calendar processing between the jacket and the opposing member. Both ends of the jacket are secured to end walls that are rotatably mounted relative to the support member, and the rotational movement of the end walls is separate from the movement of the fibrous web to prevent overheating of the jacket. Provided by the drive motor.

  The method according to the invention for adjusting the surface of the coated or uncoated paper with a surface conditioning device is characterized by what is given in the features of claim 13. The method includes feeding the fibrous web through an extended nip established by a roll in the form of a tubular flexible jacket and an opposing roll. The jacket bends or folds over the length of the nip, thereby pressing it into contact with the opposing roll over a long stretch. Paper treated with this method is lighter than currently available paper grades, but the stiffness and surface properties are comparable to currently available paper.

  This solution allows for significantly higher travel speeds than those achieved with a super calendar. Furthermore, the running performance is good, which contributes to quality improvement and reduces waste.

  The web speed in the calendar is higher than 600 m / min, preferably higher than 800 m / min, more preferably higher than 1000 m / min and can be as high as about 4000 m / min. Thus, the calendar does not limit the speed of the paper machine and does not require several calendars in parallel. The heated roll described above has a temperature of 150-350 ° C, preferably 170 ° C, and most preferably about 200-250 ° C. The linear pressure at the nip is in the range of 100-500 kN / m, preferably less than 400, and most preferably in the range of about 320-380 kN / m. The maximum pressure at the nip is 3-15 MPa, preferably less than 13 MPa, and most preferably about 8-12 MPa.

  The calendar suitable for the surface treatment of paper according to the present invention will be described in detail with reference to the drawings.

  In FIG. 1, the paper 80 travels through an extended and heated nip 1. The nip 1 is established by a fully closed shoe roll 10 that exists under the web 80. Above the web 80 is a counter roll 22 that can be heated. The fully closed shoe roll includes a flexible jacket 12 that is impermeable to water. The jacket is made of, for example, a fiber-reinforced polyurethane. A fixed fixed support member 14 supports at least one load shoe 18. Between the load shoe 18 and the support member, there is an actuator such as a hydraulic cylinder, which urges the concave load shoe 18 to press the flexible jacket 12 against the opposing roll 22. Accordingly, the jacket 12 is loaded so as to leave the neutral no-load position 11 in a direction away from the center of the fully closed shoe roll. The jacket 12 is secured to the end walls 24, 26 at both ends, thus creating a sealed compartment 13 (see FIG. 2). As also shown in FIG. 1, at least one detection device 99 is mounted in conjunction with the web 80 to detect web breaks. The detection device 99 is connected to a control device 98 that controls the operation of calendar processing according to whether or not the web is torn.

  As shown in FIG. 1, the heatable counter roll 22 is accompanied by a disengagement mechanism including a lever 95 having a pivot point 96 that can be rotated by a hydraulic cylinder assembly 94 and serves as a rotation axis. The disengagement mechanism pushes the opposing roll 22 into engagement with the nip 1 and causes it to disengage from the nip 1.

  Pressurized oil is supplied between the load shoe 18 and the jacket 12, whereby hydraulic pressure is developed across the nip and the jacket is pushed into engagement with the opposing roll 22 across the nip 1. At the same time, the oil prevents the jacket from being damaged from lumps and temperature increases.

  In FIG. 2A, the end walls 24, 26 are shown rotatably mounted on the stub shafts 16, 17 of the support member 14 (the end walls are preferably not integral; As shown in Fig. 3, it is divided into a static part and a rotating part.) A cylindrical shaft 32 is rotatably disposed at one end of the stub shaft via a bearing 34. The support column 36 is disposed on the cylindrical shaft via a self-aligning bearing 38 that allows movement of the spheres to allow deformation / bending of the support member 14 in response to heavy loads. One end of the end portion 24 is fixed to the cylindrical shaft. In the illustrated embodiment, the power transmission mechanism 40, which is a cogwheel, is fixed to the cylindrical shaft outside the end wall. The cogwheel is connected to the transmission device 42 and the drive device 44. The drive shaft 48 is supported by a bearing 70 disposed in a bearing housing 52 that is attached to a support member. A gear wheel 54 is disposed at the end of the drive shaft. Preferably, these cogwheels have an extended tooth portion to allow axial movement of the meshing cogwheel attached to the end wall. A further cogwheel 56 is secured to the second end wall 26 in the jacket. Both cogwheels inside the jacket mesh with corresponding cogwheels on the drive shaft. The second end wall 26 is rotatably disposed on the second stub shaft 17. The second stub shaft is fixed to the second support column 58.

  Operation proceeds as follows. During normal operation, the driven heated roll 22 reacts with the fibrous web and the flexible jacket 12 due to the desired pressure applied by the load shoe 18, thereby causing friction-based driving of both the fibrous web and the flexible jacket. Is caused. Thus, during normal operation, the force applied to the nip imparts rotation of the fully closed shoe roll.

  Only in special cases, for example when starting the calendar, it would normally be desirable to operate the independent drive of the fully closed shoe roll 10. If the calendar is activated without first accelerating the flexible jacket 12, it will damage the flexible jacket due to overheating. Furthermore, it develops an exponential tension in the fibrous web during the start-up movement, which will degrade the fibrous web. Accordingly, the independent drive of the fully closed shoe roll is used when the surface calendar process is started. At startup, the nip gap is not closed, but the roll 22 has been moved to a position where it does not contact the nip 1. Prior to moving the heated counter roll 22 into the nip, the drive 44 of the fully closed shoe roll 10 is actuated to accelerate the first end wall 24 via the transmission. The rotation of the end wall causes the rotation of the inner first cogwheel 46 and subsequently the rotation of the drive shaft 48. The drive shaft transmits rotation to the second end wall 26 via a second cogwheel 56. Both end walls are thus accelerated and rotated at the same speed until a desired peripheral speed is obtained which is usually equal to the speed of the fibrous web. The nip is closed by actuating the hydraulic piston 94 to rotate the lever 95, thereby moving the opposing roll 22 into the nip, and the load shoe 18 is subsequently attached to the heating roll 22 by its actuator 20. Forced to contact. When the calendar functions in the desired manner, the drive for the fully closed shoe roll can be deactivated and the press roll can be driven in a conventional manner by frictional forces in the nip 1.

  In FIG. 2B, an alternative embodiment of a drive mechanism for a fully closed shoe roll is shown. This embodiment uses friction to transmit the rotational force.

  FIG. 2B also shows a more preferred layout design for the support members and end walls. The end wall is divided into an inner portion 24A; 26A that is non-rotatably connected to the support member 14, a rotating portion 24B; 26B, and a bearing assembly 24C; 26C therebetween. Self-aligning bearings 23 and 25 that allow the support member 14 to bend are disposed at each end of the support member 14.

  In the figure, a drive device 44 having a shaft 19B is shown. A disk 19 having a rubber layer on its peripheral edge 19A is mounted on the shaft 19B. The other end of the flexible jacket 12 is fixed between an annular ring 15 that functions as a replaceable force transmission device and the periphery of each end wall. The ring 15 is fixed to the end wall. Fitting gears 46 and 56 are fixed inside the rotating portions 24B and 26B of the end walls. The drive devices 44 and 19 can move to a contact state or a non-contact state with the force transmission device 15. When it is desired to accelerate the fully closed shoe roll 10, the driving device is moved so that the rubber layer 19 </ b> A is in a frictional engagement position with the force transmission device 15. The cogwheel 46 and the drive shaft transmit rotation of the end wall 24 to the other end wall 26 by cogwheels 54, 55, 56 that also function as a synchronizer. Thus, both end walls 24, 26 are operated as described above with reference to FIG. 2A. FIG. 2B schematically further illustrates one preferred functional embodiment of the load shoe 18. Generally, the load shoe 18 is not diametrically disposed with respect to the drive shaft, but is disposed at a right angle as in FIG. 2A.

  The test was a test batch produced by a long nip calender as described above, and the paper batch could have a better bulk ratio and smoothness compared to the currently available paper grades. Therefore, according to the measured values, the object of the present invention is satisfactorily satisfied.

  The shoe calendar can be driven at a very high speed, and the final gloss finish uses a super-calendar by considering the addition of a high temperature such as about 250 ° C. and the long residence time in the calendar region. It will be equivalent to that achieved with a slower solution. In addition to aspects that directly contribute to paper quality, the results include saving mill production space, reducing super calender production constraints, and providing a more manageable and easier control system.

  From the papermaking point of view of the present invention, a non-contact coating process is used prior to the final calendering of the polish. Suitable coating methods include, for example, curtain type or spray type coating.

The quality values of the paper thus produced under pilot conditions were as follows:
Bulk 1.15-1.3cm ³ / g
PPS-s10 Roughness 1.0-1.5μm
Gloss 40-50%
Compared to previous known grades, in addition to the resulting paper being bulky and smooth, the manufacturing method has a higher production capacity than that achieved with a single supercalender. The method provides savings in paper manufacturing and improves economy. In particular, an increase in capacity is possible with the same paper machine by online calendar processing. Compared to using several supercalenders, more space can be saved if the operation of a new or old mill is streamlined. Providing higher bulk represents a direct savings in the amount of material and energy required for production, as well as lighter printing paper saves energy over its life and ultimately reduces the amount of waste to be processed Is generated.

FIG. 4 is a cross-sectional view of a long nip calendar with a nip extended between the shoe calendar and the opposing roll. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 2 is a partial cross-sectional view of the apparatus shown in FIG. 1 showing the drive mechanism along the roll axis. It is a figure which shows operation | movement of a press shoe in the cross section of a longitudinal direction.

Claims (15)

A coated printing paper product, the final calendar used after the coating process includes a surface conditioning device;
The surface conditioner is
A fixed support member (14);
A flexible jacket (12) provided around the stationary support member (14) so that the paper web (80) runs between the jacket (12) and the counter roll (22);
A flexible web (12) is pressed against a heatable counter roll (22) by a load member (18, 20) and a paper web (between the jacket (12) and the counter roll (22) ( Load members (18, 20) provided in relation to the support member (14), so that 80) is calendered;
At least one end wall, wherein the flexible jacket (12) is attached to the end wall (24, 26), and the jacket (12) is driven by a drive mechanism to the end wall (24, 26). An end wall mounted at the end of the jacket (12) for rotation with the
The coated product is a surface property of the top surface of paper.
PPS-s10 roughness (ISO 8791-4) is 0.7-1.5 μm
Hunter Gloss (ISO / DIS8254) is 30-80%,
The product, characterized in that it has a bulk in the range of 1.15 to 1.3 m ³ / kg.   The product according to claim 1, which is for offset printing.   The product of claim 1 or 2, wherein the top surface is coated one or more times.   The product according to any one of claims 1 to 3, wherein the back surface is coated.   The product of claim 4, wherein the back surface is coated one or more times.   The product according to any one of claims 1 to 5, wherein the coating is provided by a non-contact coating process. Surface density is in the range of 30-100g / ^{m 2,} Product according to any one of claims 1 to 6. Surface density is in the range of 40-70g / ^{m 2,} Product according to any one of claims 1 to 5.   9. Product according to any of the preceding claims, wherein the top surface has a Hunter Gloss (ISO / DIS 8254) in the range of 25-90%, preferably 50-70%. The product has a density in the range of ^{770-870kg / m 3 (SCAN-P7} : 75) having a product according to any one of claims 1 to 9.   11. A product according to any preceding claim, wherein the calendering of the product involves the use of a single nip or multiple nip machine and / or a pre-calender of a soft calendar.   12. A product according to any of claims 1 to 11, wherein the pre-calendering of the product involves the use of paper surface wetting.   12. A product according to any of claims 1 to 11, wherein the pre-calendering of the product does not involve the use of paper surface wetting. A method for making a coated paper product,
Having the coated paper product is at least one fiber layer has a surface density in the range of 30-90g / m ^2, the web to be coated, comprising the steps guided into the surface conditioning apparatus after the coating process ,
The surface conditioner is
A fixed support member (14);
A flexible jacket (12) provided around the stationary support member (14) so that the paper web (80) runs between the jacket (12) and the counter roll (22);
A flexible web (12) is pressed against a heatable counter roll (22) by a load member (18, 20) and a paper web (between the jacket (12) and the counter roll (22) ( Load members (18, 20) provided in relation to the support member (14), so that 80) is calendered;
At least one end wall, wherein the flexible jacket (12) is attached to the end wall (24, 26), and the jacket (12) is driven by a drive mechanism to the end wall (24, 26). An end wall mounted at the end of the jacket (12) for rotation with the
A method comprising final calendering of the web by the surface conditioning device.   The method according to claim 14, wherein the coating process before the final calendar process is performed using a non-contact coating process.

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