JP4906500B2 - Matte calendar finish - Google Patents

Abstract

A paper mill has a matt satin-finisher assembly in which a surface-coating agent is applied to one side of the moving web prior to passage through a heated glazing gap. The glazing gap is longer than prior art. The linear forces in the heated glazing gap are above 300 N/mm, and the press surface temperature in the glazing gap is between 90 and 130C. The length of each glazing gap is 40 - 90 mm and the assembly has two heated glazing stations, one acting on each side of the paper web. Also claimed is a commensurate process in which the web feeds through a heated glazing gap, and an elastic glazing gap formed by two press surfaces of which one or both are elastic. The elastic gap is located prior to or after the heated glazing gap.

Description

  The present invention relates to a method and apparatus for matting and calendering webs, cardboard webs or other fiber webs with a machine for producing and / or finishing the webs, in which at least one of the fiber webs The sides are coated by an applicator and then the fibrous web is guided through at least one heated smoothing gap.

  The coated fiber web is usually smoothed with a soft calender. In this case, there is a problem in forming smoothness suitable for printing without giving too much gloss to the surface.

  This has not been fully achieved so far.

  Accordingly, an object of the present invention is to improve the smoothness during matte calendar finishing.

  According to the present invention, the above-described problems are that the smoothing gap is extended, the linear force of the heated smoothing gap is more than 300 N / mm, and the press surface of the heated smoothing gap is 90 to 130 ° C. It is solved by heating at a temperature of.

  The fiber web stress due to the high linear forces not common in matte calendering is relativized due to the extended form of the smoothing gap.

  This eliminates the need to worry about too much reduction in volume during matte calendering. However, the smoothness is significantly improved by the longer residence time of the fiber web in the smoothing gap.

  The temperature in the smoothing gap is also much higher than that seen with other matte calendar finishes. Surprisingly, it has been found that higher temperatures associated with longer residence times positively affect smoothness but do not affect gloss in the same range.

  In order to be able to guarantee a sufficient residence time, especially at high machine speeds, the length of the heated smoothing gap should be 40-90 mm.

  The heated press surface should be formed from a heated smooth finish roller for simplicity.

  In order to form an extended smoothing gap, the pressing surface opposite the heated pressing surface should be formed as a roller with an elastic cover or as a shoe press roller.

  In this case, to save the fibrous web, the flexible roller jacket of the shoe press roller should have a hardness of less than 95 Shore (A) at least on the surface.

  In order to minimize the double-sided nature of the fibrous web, both sides of the fibrous web should be coated by an applicator.

  It is further recommended to guide the fibrous web through at least two smoothing gaps to complete the matte calendar finish.

  If the two smoothing gaps are heated and are two extended smoothing gaps, the heated press surfaces of the heated smoothing gaps should be placed on various sides of the fiber web. Let's go.

  Only in this way a corresponding press surface temperature rise can consequently affect both sides of the same range of fiber webs.

  However, it can be advantageous if the fibrous web travels through a heated and extended smoothing gap and an elastic smoothing gap, in which case the elastic smoothing gap is formed by two pressing surfaces, of which At least one press surface has an elastic cover.

  In order to simplify the structure, the elastic smoothing gap should be formed by two press rollers, of which at least one press roller has an elastic cover. The extension of the smoothing gap is likewise obtained by the elastic cover.

  In addition, the two press rollers provide the advantage of being able to profile, in particular, the fiber web thickness, in the elastic smoothing gap.

  Depending on the type of fibrous web and the requirements for the fibrous web, it may be advantageous if an elastic smoothing gap is arranged before or after the heated smoothing gap.

  Here, fiber webs, in particular paper webs having a gloss value of Tappi 75 of less than 35%, are considered non-glossy. In this case, Tappi 75 is a method for measuring the reflection gloss of the paper at 75 ° according to the test method Tappi T480.

  Hereinafter, the present invention will be described in detail with reference to two examples.

  In both cases, the fibrous web 1 is applied on both sides while passing through the application device 2 before calendering. This forms the basis for an essential improvement in surface properties.

  Next, the fibrous web 1 is heated and guided through the extended first smoothing gap. This smoothing gap is formed by a smooth finishing roller 4 arranged under the heated cylindrical and fibrous web 1 and by an upper shoe press roller 3.

  The shoe press roller 3 has a flexible roller jacket 7 that is pressed against the smooth finish roller 4 by a pressure-bonding element 8 having a concave press surface. The roller jacket 7 has a hardness of less than 95 Shore (A), and is sufficiently soft so as not to damage the surface of the fiber web 1.

  The smoothing gap is extended to a length of 40 to 90 mm via the concave press surface. Due to the longer residence time of the fibrous web 1 in the smoothing gap caused by this, the linear force can be increased to a value above 300 N / mm without the risk of too much volume reduction.

  The temperature of the roller jacket of the smooth finish roller 4 to be heated is 90 to 130 ° C., and contributes to an essential improvement in smoothness in association with a long residence time.

  In order to further improve the smooth finish of the fibrous web 1, in this regard, in the case of the configuration according to FIG. 1, a heated and extended second smoothing gap follows. In view of the minimized double-sided nature of the fiber web 1, the heated smooth finish rollers 4 are arranged on different sides of the fiber web 1.

  In the case of the form shown in FIG. 2, the elastic smoothing gap follows the heated smoothing gap in the web running direction 9.

  This elastic smoothing gap is formed by two press rollers 5, 6 having elastic roller covers. Also in this case, the extended smoothing gap is set by the elasticity of the roller coating.

  This elastic smoothing gap is less expensive than the smoothing gap from the shoe press roller.

  The resulting improvement in smoothness is satisfactory for many applications. Furthermore, the same treatment reduces the double-sided nature that the fibrous web 1 may be present.

  In both cases, it may be advantageous to humidify the fibrous web 1 in particular in front of a heated and extended smoothing gap in order to at least partly correct the water loss during the smoothing process.

1 is a drawing of an apparatus having two smoothing gaps that are extended and heated. 1 is a drawing of an apparatus with only one smoothing gap that is extended and heated to produce a non-glossy fiber web 1, in particular a paper web.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fiber web 2 Application | coating apparatus 3 Shoe press roller 4 Smooth finishing roller 5, 6, 8 Press roller 7 Roller jacket 9 Web running direction

Claims (16)

A method for matting and calendering the web (1) with a machine for producing and / or finishing a paper web, cardboard web or other fiber web (1), wherein at least one of the fiber webs (1) In a method in which one side is coated by means of an applicator (2) and then the fibrous web (1) is guided through at least one heated smoothing gap,
The smoothing gap is extended, the gap is formed by a shoe press roll (3) and smooth finishing rolls (4), the line force of the smoothing gap being heated is 300N / mm greater, and is heated the press surface of the smoothing gap is heated at a temperature of 90 to 130 ° C., has a roller outer hardness surface is less than 95 Shore (a) of the (7) of the shoe press roll (3), and 35% how to produce a fibrous web having a gloss value of Tappi75 below.     The method according to claim 1, wherein the length of the heated smoothing gap is 40 to 90 mm.     3. A method according to claim 1 or 2, characterized in that the fibrous web (1) is guided through two heated smoothing gaps.     4. The method according to claim 3, characterized in that the heated pressing surface of the heated smoothing gap is arranged on various sides of the fibrous web (1).     The fibrous web (1) travels through a heated smoothing gap and an elastic smoothing gap, wherein the elastic smoothing gap is formed by two press surfaces, The method according to claim 1 or 2, characterized in that at least one of the press surfaces has an elastic cover.     6. A method according to claim 5, characterized in that the elastic smoothing gap is arranged in front of the heated smoothing gap.     6. The method of claim 5, wherein the elastic smoothing gap is disposed after the heated smoothing gap.     8. A method according to any one of the preceding claims, characterized in that a coating is applied on both sides of the fibrous web (1) by the applicator (2). In order to carry out the method according to any one of the preceding claims, the web (1) is polished with a machine for producing and / or finishing a paper web, cardboard web or other fiber web (1). An apparatus for finish calendering, wherein at least one side of the fiber web (1) is coated by a coating device (2) and then through at least one heated smoothing gap In the apparatus in which (1) is guided,
The smoothing gap is extended, the gap is formed by a shoe press roll (3) and smooth finishing rolls (4), the line force of the smoothing gap being heated is 300N / mm greater, and is heated the press surface of the smoothing gap is heated at a temperature of 90 to 130 ° C., has a roller outer hardness surface is less than 95 Shore (a) of the (7) of the shoe press roll (3), less than 35% device you producing a fibrous web having a gloss value of Tappi75 of.     10. A device according to claim 9, characterized in that the heated pressing surface is formed from a heated smooth finish roller (4). The apparatus according to any one of claims 9 to 10 , wherein the length of the heated smoothing gap is 40 to 90 mm. Device according to any one of claims 9 to 11 , characterized in that the fibrous web (1) is guided through two heated smoothing gaps. 13. Device according to claim 12 , characterized in that the heated pressing surface of the heated smoothing gap is arranged on various sides of the fibrous web (1).     The fibrous web (1) travels through a heated smoothing gap and an elastic smoothing gap, wherein the elastic smoothing gap is preferably formed by two press rollers (5, 8). The apparatus according to any one of claims 9 to 12, wherein at least one of the two press rollers has an elastic cover. 15. An apparatus according to claim 14 , characterized in that the elastic smoothing gap is arranged in front of the heated smoothing gap. 15. An apparatus according to claim 14 , characterized in that the elastic smoothing gap is arranged after the heated smoothing gap.

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