Abstract: A method for pre-calendering a board web is provided and comprises passing the board web in a pre-calendering process through at least one hard nip, formed by a metal roll and a counter roll, and through at least one long nip, formed by a thermo roll and a long-nip roll or a long-nip belt assembly. The surface of the board web is moistened with water prior to the board web passing through the at least one hard nip.

Abstract: In the method for treating the surface of the web, liquid is added on the surface of a paper or paperboard web (W), possibly with other constituents. The absorbency of the surface of the paper or paperboard web is increased before liquid is brought on the surface of the web or simultaneously with bringing the liquid on the surface of the web. The method is used for wetting the surface of the web before calendering, or for coating the web in surface sizing or pigmenting. The absorbency of the surface is increased before bringing the liquid for example by means of a corona treatment, a flame treatment, an ozonization or by adding steam.

Abstract: A method for pre-calendering a board web is provided and comprises passing the board web in a pre-calendering process through at least one hard nip, formed by a metal roll and a counter roll, and through at least one long nip, formed by a thermo roll and a long-nip roll or a long-nip belt assembly. The surface of the board web is moistened with water prior to the board web passing through the at least one hard nip.

Abstract: A method for managing the water sorption of a board by layered sizing is provided, such that the sizing of a central layer is effected with a hydrophobic and fast-curing adhesive, and the surface sizing in preparation for calendering is effected with an adhesive which is hydrophilic during its curing period, such that, during a surface wetting process, water sorption occurs substantially only into a topliner.

Abstract: A long nip (N) shoe calender formed of a shoe roll (10) and a thermo roll (20) is used in calendering, with a nip dwell time which is over 10 ms, advantageously over 20 ms. The nip pressure is below 3 MPa, advantageously below 1 MPa, and a surface temperature of the thermo roll (20) is over 200° C., advantageously over 250° C. The board web (W) surface to be pressed against the thermo roll (20) is moisturized before the nip.

Abstract: A supercalender for calendering a paper web and a calendering arrangement for producing matte-quality paper web has a multiple-nip calender in which at least one of the calendering nips of the multiple-nip calender is an extended nip (N9) formed between a polymer roll (18) and either a shoe roll (30) or a calendering belt.

Abstract: A method and apparatus for calendering paper or board in the manufacture of coated grades of paper or board. At least one of the surfaces of an uncoated base material web is calendered, at least one layer of coating mix being applied onto said surface, and at least the coated surface of the base web is calendered again. The uncoated surface of the base web is calendered by means of a shoe calender having a nip length of at least 50 mm, and the coated surface of the base web is calendered by means of a calender having a nip length of 50 mm at the most.

Abstract: In the method, a long nip (N) shoe calender formed of a shoe roll (10) and a thermo roll (20) is used. In calendering, a nip dwell time which is over 10 ms. advantageously over 20 ms. a nip pressure which is below 3 MPa. advantageously below 1 MPa. and a surface temperature of the thermo roll (20) which is over 200° C. advantageously over 250° C. are used. In addition, the board web (W) surface to be pressed against the thermo roll (20) is moisturized before the nip.

Abstract: The present invention relates to a supercalender for calendering a paper web and a calendering arrangement for producing mat-quality paper web. The multiple-nip calender of the invention is characterized in that at least one of the calendering nips of the multiple-nip calender is an extended nip (N9) formed between a polymer roll (18) and either a shoe roll (30) or a calendering belt.

Abstract: In the method in moistening of a web, water is applied with a wetting device (2) in a predetermined point on the surface of a paper web (W) or the like passing by the point, and the web is thereafter passed to a calender (C). The liquid is applied at such an early stage that before the surface treatment, the fibres exposed to wetting in the paper web (W) or the like have the time to absorb it at least 80% of the amount of liquid they are capable of absorbing. The distance travelled by the web between the drying section and the calender is increased with rolls (1) which guide the web (W) along a winding path.

Abstract: A method and apparatus for coating a paper or board web, wherein the web to be coated is brought to a film transfer coater and taken to a nip between the film transfer roll of the coater and its backing roll, and coating mix is applied onto the surface of the film transfer roll. The web is taken through the nip between the rolls and the rolls are turned, whereby the coating mix applied onto the applicator roll is at least partly transferred onto the surface of the web. The web is supported through the nip by means of a belt traveling at the same speed as the web, the belt having been arranged to travel on the backing roll. The web is taken onto the surface of the belt prior to the nip and separated from the belt after the nip, and it is pressed against the film transfer roll by means of the belt. The length of the path where the web and the film transfer roll are in contact with each other is controlled by varying the position of the web and the belt.

Abstract: A method and apparatus for producing calendered paper by an on-line manufacturing system comprising at least a paper machine and a multi-nip calender. The method comprises following steps: removing water from a formed paper web by pressing, drying the pressed paper web by at least one dryer, calendering the dried web by the multi-nip calender, measuring a cross-machine moisture profile or a variable relative thereto, and altering the moisture of the web so that the moisture profile of the web in the cross-direction is even when the web enters the first nip of the calender.

Abstract: A paper web is passed through a calendering nip that is formed between a roll which has been provided with a soft face and a heatable hard roll. The heatable roll is heated so as to plasticize the surface layer of the paper web that is placed at the side of the heatable roll, preferably so that the temperature of the surface layer in the calendering nip exceeds the glass-transition temperatures of the polymers contained in the paper. Before entering into the calendering nip, the paper web is moistened, so as to lower the glass-transition temperatures of the polymers contained in the paper, and pre-heated. The pre-heating of the paper web is carried out by bringing the paper web into contact with the heatable roll before the web enters the calendering nip and by, before the calendering nip, feeding steam or water onto the face of the paper web that is placed at the side of the heatable roll so as to improve the transfer of heat from the hot roll to the paper web.