FI120464B - Process for producing and rolling-up a fiber web coated with a heat and / or pressure-sensitive coating - Google Patents

Description

Method for Making and Rolling a Fiber Web with Thermally and / or Pressure Sensitive Coating

The present invention relates to a process for the production and rolling of a fiber web with a heat and / or pressure sensitive coating which is sensitive to frictional action.

When fusing a heat- and / or pressure-sensitive product, friction should be avoided during roll-up. In conventional retractors, precise control of the winding event 10 is difficult, which is why winding of a heat and / or pressure sensitive product is typically done in a nip open position. This limits the travel speed, because at high speeds the nip must be closed in order to control the taxiing event.

It is an object of the present invention to provide a method by which the above problems can be eliminated. To achieve this object, the method according to the invention is characterized by the features set forth in the characterizing part of claim 1. Parameters that influence friction formation include track tension, line load and circumferential force.

Preferably, the application of the heat and / or pressure sensitive coating is done by a curtain coating method in which a multilayer coating can be used, whereby all layers can be applied in one step. The coating application can also be done in several different steps. The protective layer becomes the top 25 and the friction sensitive layer or layers the bottom.

The invention will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 schematically illustrates a prior art winding device, and 2

Figure 2 shows schematically the factors affecting the formation of the machine roll.

Fig. 1 shows a schematic perimeter 5 of a reel winder according to FI91383, comprising a rail 10 formed in a frame structure on which a reel roll is disposed on which the web W is rolled into a machine roll 20 through a winding cylinder 15 through a nip N. The reel spool rotates in the direction of the arrow S2 by means of the center drive 44. The retractor includes a reel roll transfer device 45 and a support device 40 and a cylinder 41. The device further includes transfer means 32 for bringing the new reel roll 10 into a standby position. Reference numeral 35 denotes a press roll which is nip-contacted with a full machine roll 20 before the roll is removed from the nip-contact with the winding cylinder. The press roll 35 is used to prevent air from entering the machine roll 20 between the remaining top layers.

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Figure 2 schematically illustrates the factors affecting machine roll formation, such as track tension, line load in the nip, and circumferential force.

In conventional retractors, the roll formation of fiber webs equipped with temperature and / or pressure sensitive coatings is mainly controlled by web tension, since the roll is done in a nip open mode so that the coating does not suffer from a frictional effect which causes it to darken. For carrying out the method according to the present invention, for example, the roller disclosed in the applicant's prior patent FI116217 can be used to adjust the parameters affecting the winding. The roller disclosed in FI116217 is not further described herein but merely by reference to that patent.

The web tension causes the paper to stretch before the reel roll. To measure the track tension 30, a tension measuring roller 30 is placed in front of the winding cylinder. The track tension is adjusted according to a given value (curve) and the measured tension value by electrical operation of the winding cylinder 15. Typically, tension is sought to be maintained at a constant value, preferably with a control accuracy of +/- 20N / m.

When the nip is closed, the machine roll 20 formed on the reel roll is 5 against the winding cylinder 15, causing the line load F on the nip N to tighten the roll in the nip between the machine roll and the winding cylinder. The linear load is controlled by the measurement of the load cylinders of the primary and secondary winders. The loading cylinders of the primary winding and secondary winding units receive loading pressure instructions as a function of the selected curve and the diameter of the machine reel formed by the 10 reel rolls. Applying excessive line load to the winding nip causes the roll to be tensioned by stretching the web and this results in frictional action between the various layers of the machine roll, which adversely affects heat and / or pressure sensitive fiber webs. The line load is preferably in the range of 1-6 kN / m.

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The third parameter affecting the roll of the machine roll is the circumferential force, which turns the roll tight. The perimeter power is controlled by the torque of the primary and secondary motors. The adjustment accuracy is preferably in the range of +/- 20N / m. First use refers to the use of a new reel reel introduced into the rewinding station by a primary winder 20 for performing initial acceleration and reeling of the reel reel to secondary winding, and to use a reel that is currently being rolled on a secondary winder.

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Claims (3)

A method of producing and rolling a fiber web provided with a heat and / or pressure sensitive coating, which coating is sensitive to frictional impact, characterized in that the coating is made as a multilayer ridging coating, with a protective layer being formed on said heating layer. and / or pressure-sensitive coating layers, which protective layer is substantially free from friction-sensitive components, and which coated fiber web is rolled with a roller, which in a controlled way can affect the parameters acting on the friction formation during rolling, in which the roller web is inserted. through a closed roll nip (N). 2. A method according to claim 1, characterized in that the parameters controlled by the inverter are the web voltage, the line load and the peripheral force. 3. A method according to claim 2, characterized in that the peripheral force is controlled by regulating the torque of the motors of the primary and secondary drives. 20