FI115147B - Method and apparatus for determining the amount of adhesive transferred from a film transfer coating device to a web - Google Patents

Description

115147

The present invention relates to a method according to the preamble of claim 1 and to an arrangement according to the preamble of claim 6 for applying an adhesive to be applied from a film transfer applicator to a web or an adhesive to be applied to a web or adhesive.

In order to improve the properties of paper or board, the base paper or board web is treated differently. The purpose of the treatments is to improve the strength and / or printability properties of the material being manufactured. In addition to bulk bonding, surface bonding is used to increase the strength with chemicals, in which an adhesive, such as starch, is applied to the web surface to increase the web strength and stiffness. Surface sizing also improves the printing properties of paper or cardboard. Surface sizing prior to coating smooths out unevenness on the] # surface of the web, resulting in a smoother application of the coating material | * · * · I; ; * to the web.

| • · · · ....: Surface sizing is traditionally done with a pond adhesive press, where the • · ....: web is run vertically between two nip formed by opposite rolls.

A surface glue is applied to the nip between the rolls so that it remains a pond on the roll. Adhesive is adhered to the web passing through the pond and the amount of glue dispensing is mainly done by adjusting the dry matter of the glue. The advantages of the process are a large amount of ·· · * appliqué, which is particularly advantageous in the manufacture of paperboard. Carton: * ·· The strength depends strongly on the amount of glue used.

• Pond glue presses deliver the highest strengths with thick • · ·: · board grades. For pond adhesive presses, the application rates are typically between 20 · 100 ml / m and the application rates on both sides of the track add up to 2,115,147. Typical amounts of adhesive for corrugated board, i.e. liner and corrugated board, are 70-90 ml / m2.

Lammikkoliimapuristinten weakness of the ponds, turbulence and track the revenue side to be treated by vibrations due to poor driveability, which limits coating speed. At present, the maximum speed for pond glue presses is 900 m / min. In pond application, a large amount of water is also absorbed into the web, partly due to the application method and partly due to the low dry solids content of the adhesive, only about 10%. With the above-mentioned dry matter content and application rate, the adhesive mixture will leave 8-10 g / m 2 of adhesive after drying.

Large amounts of water weaken the course and increase the need for drying power. Heavy wetting of the web is a major problem, especially for heavy paperboards, since the drying power absorbed deep into the web requires a lot of drying power. A further disadvantage of pond glue presses is that the amount of glue can not be adjusted differently on different sides of the web except by leaving the web completely untreated on one side.

• ·! ! The surface sizing can also be done with a film transfer coating where the V web to be processed passes through a nip between two rolls. The adhesive is applied by means of a special ...: applicator on the surface of one or both rolls, from where it moves to the surface of the web to be treated in a nip between the rolls. On the roll surface:: The thickness and profile of the air layer can be adjusted, for example, with a rotating 2 ° doctor blade or a doctor blade. The film transfer coaters have good runnability, * * but have the disadvantage of a limited amount of application. Film Transfer •; · 'The maximum amount of application on one side of the web in surface sizing is about 20-30:' ·· g / m2.

• · • · i.: 25 The application of the adhesive layer is hindered by the fact that it is not possible to measure the amount of adhesive or '· · ·' adhesive applied to the web during production. In this case, 3 115147 possible quantity or profile errors cannot be corrected during production. The amount of adhesive on the surface of the film transfer applicator roll has been measured by removing the adhesive from the surface of the rotating roll with a separate scraper, and determining the amount and profile of adhesive on the removed layer. However, this cannot be done during production. Also, the amount or profile of the adhesive cannot be measured from the surface of the web, since the adhesive and the water contained therein are rapidly absorbed into the web, which makes measurement impossible. The operation of coating quantity measuring devices is based on the measurement of the amount of minerals contained in the coating, so they cannot be directly used to measure the amount of adhesive used in surface sizing.

When applying thin layers of adhesive, a smooth scraper rod is used in the film transfer coating. Surface gluing with a smooth scraper rod is difficult because the profile of the adhesive layer applied to the web cannot be adjusted sufficiently precisely.

I 15 Furthermore, the load change of the smooth scraper rod affects the profile of the adhesive layer on the surface of the applicator roll differently from the • ·: 'grooved. · Scraper rod. When using a groove bar, the wear of the groove profile causes • »:.:: Changes in the adhesive layer profile. A prerequisite for accurate profile adjustment • · ·: In surface sizing, the amount and profile of adhesive transferred to the web can be determined while the film transfer coating is being run.

The object of the present invention is to provide a novel method and ....; arrangement for determining the amount of adhesive to be transferred from the applicator roll of the film transfer coating to the web.

25: '': The invention is based on determining the amount of water contained in the adhesive layer on the surface of the film transfer applicator roll: v. By measuring: * * ': attenuation of the infrared absorption wavelength in the adhesive layer.

The amount of water can be used to determine the amount of adhesive on the surface of the roll, 4,115,147, since the dry solids content of the adhesive mixture to be applied to the applicator roll is known quite accurately. Further, the amount of glue transferred to the web can be determined by the assumed or measured transfer coefficient between the applicator roll and the web. By measuring the amount of adhesive at several locations 5 across the width of the applicator roll or by using a measuring device moving in the width direction of the roll, the adhesive profile can be determined in the width direction of the web.

More specifically, the method according to the invention is characterized in what is stated in the characterizing part of claim 1.

10

The arrangement according to the invention, in turn, is characterized by what is stated in the characterizing part of claim 6.

The invention provides considerable advantages.

15 1 The amount and / or profile of adhesive applied to the web can be monitored. during the production of the film transfer coating. Amount and profile of adhesive if needed: Adjusts scraper load and load profile during production • · ·: by changing. By means of the invention, small amounts of adhesive, with high solids content, can be applied to the web, which reduces the need for drying the web ... after surface sizing. Although the invention is primarily used to determine the amount of adhesive and / or .... to be transferred from the film transfer coating applicator roll to the web, it can also be used to determine the amount and / or profile of the film transfer coating from the application roll to the web: ·. 25 to determine.

*. ·. ·. The invention will now be described in more detail with reference to the accompanying drawing, which is a side view of a film transfer coating for surface sizing.

5, 115147

The film transfer coating 7 shown in the drawing comprises two rotary appliqué rolls 1, 2 arranged in a nip contact between which the surface-adhesive web 3 is arranged to pass. The direction of travel of web 3 is indicated by an arrow. Adhesive used for surface sizing of paper and cardboard is applied to the surfaces of both application rolls 1, 2 by means of short-stay application apparatus 4. The application apparatus 4 comprises an application chamber adjoining the roll 1, 2. In the direction of rotation of the roll 1,2, the applicator chamber is delimited by front and rear walls which are scraper blades or scraper blades arranged against roll 1, 2. The glue is fed to the applicator chamber 10, from where it moves to the surface of the roll 1, 2. The adhesive layer is leveled and its thickness is adjusted using a doctor blade acting as a front wall of the appliance chamber or a smooth or grooved doctor blade. The scraped adhesive layer moves from the application rolls 1, 2 to both sides of the surface sizing web 3 in the nip between the rolls 1, 2. If only one side of the web 3 is surface glued, the adhesive 15 is applied only to the other roll 1, 2.

! The amount of i. I: water (g / m 2) contained in the scraped adhesive layer on the surface of the applicator roller 1, 2 is measured by directing infrared radiation 6 from the fitted measuring device 6 to the adhesive layer. The radiation propagates through 20 adhesive layers and is reflected from the interface between the adhesive layer and the applicator roll 1, 2 back to the measuring device 6. The attenuation of the radiation reflected back to the measuring device 6 is measured at a specific water absorption wavelength. The wavelengths of infrared radiation at which water absorbs • radiation are 744 nm, 980 nm, 1458 nm and 1940 nm. Typically, attenuation is measured at 1940 nm. Measured by the water absorption wavelength: ""; attenuation is compared with attenuation of radiation by: v. the reference wavelength. The reference wavelength should be chosen such that; . the change in the water content of the adhesive layer does not change the attenuation at the reference wavelength of 6,115,147. The determination of the amount of water is based on the change in damping caused by water at the measuring wavelength.

The dry matter content 5 of the adhesive mixture applied to the surface of the applicator roll 1,2 is known quite accurately, whereby the amount of water (g / m 2) on the surface of the roll 1, 2 can be determined from the amount of water If the amount of water of the adhesive layer is measured at several points in the width direction of the web i or the measuring device 6 is moved in the width direction of the web 3, the adhesive volume profile 10 on the surface of the applicator roll 1, 2 In this case, there may be three measuring points, at both ends and in the middle of the applicator roll 1, 2, whereby the large-scale profile change of the amount of adhesive can be determined quite reliably. There may also be more than three measuring points. The amount of glue transferred from the application roll 1, 2 to the web 3 can be determined by the assumed or measured transfer coefficient 15 between the application roll 1, 2 and the web 3.

. ' · -: The appliance chamber scraper load and / or load profile is adjusted j; glue amount and / or profile defined using feedback control i% ..! · 'Basis. The scraper load is adjusted locally by adjusting elements such as 2 0 profile adjusting spindles. The solution according to the invention is suitable for use]. / very well in film transfer coaters, which apply small amounts of t «* adhesive with high solids content to the web. In this case, it is applied to the web. ,,.; the amount of glue is typically less than 5 g / m2 and the dry matter content of the glue is 15-40%.

. · '·: When applying small amounts of glue, the smooth scraper is preferably: ·' 25 rods.

• · · «· • ·

Although the invention is primarily used for film transfer coating. · *. for determining the amount and / or profile of adhesive to be transferred from the applicator roll to the web, it may also be used for a film transfer coating; 7,115,147 for determining the amount and / or profile of coating material to be transferred from the applicator roll to the web.

I * · · t · »·

Claims (7)

A method for determining the amount of adhesive or coating butter to be transferred onto a web (3) from an application roller (1,2) of a film transfer coating device (7) used in surface gluing a paper or cardboard web (3), in which film transfer coating device (7) - surface adhesive or coating butter is spread on the surface of the application roller (1, 2.), - the adhesive or coating layer is smoothed and scraped to the desired thickness by means of a scraper, - infrared straining is directed to the adhesive or coating layer of the application roll ( 1, 2) the surface exhibits after its creation, - the amount of water contained in the adhesive or coating layer is determined by measuring the attenuation of the infrared radiation 15. the adhesive or coating layer; - the adhesive or coating layer is transferred to the surface of the web > to be surface glued in the nip between the application rolls (1,2), and »: the amount of adhesive or coating butter to be transferred on the web (3), is determined on the basis of the determined amount of water, the solids content of the adhesive or coating, and: * the coefficient of transmission between the application roller (1,2) and the web (3), characterized by the profile of The ingot roll (1,2) is determined in the width direction of the web by determining the amount of Hm or coating butter in at least three customized s in the width direction of the web (3). 5 Method according to claim 1, characterized in that the amount of glue or coating butter is determined on the surface of both film transfer coating devices (1,2) of the film transfer coating device. Method according to any of the preceding claims, characterized in that the load or load profile of the cabinet is regulated on the basis of the amount of adhesive or coating or the profile of the adhesive or coating amount. 4. A method according to any of the preceding claims, characterized in that a filament having a smooth surface is used as the filament for the film transfer coating device. • I 15 5. Apparatus for determining the amount of glue or coating butter which; * is to be applied to a web (3) from an application roller (1,2) of a film transfer coating device (7) used in surface bonding of a »» paper or cardboard web (3), which film transfer coating device (7) * · includes »1 I. ··. 20 - two-type contact arrangement rollers (1, 2), between which the web *:. (3) to be glued or coated is arranged to run; · · -. an applicator (4) for spreading surface adhesive or. coating smear on the surface of the application roller (1,2); - »A tester for smoothing and scraping the Hm or coating layer applied to the desired thickness to the desired thickness! - a measuring device (6) for determining the amount of water that the adhesive or coating layer on the surface of the application roller (1,2) contains after the scrubber, which measuring device (6) is arranged to transmit infrared radiation against Hm or the coating layer and measuring the attenuation of the infrared radiation in the Hm or j coating, and 10. means for determining the amount of Hm or coating butter to be transferred onto the web (3), on the basis of the determined amount of water, the glue or coating's dry matter content and the transmission coefficient between the application roll; (1,2) and the web (3), characterized by; ; * - at least three measuring devices (6) are arranged in the width direction of the web (3) to determine the profile of Hm or coating; the coating amount layer on the surface of the application roller (1,2) in: the width direction of the web (3). Film transfer coating device according to claim 5, characterized in: - a means for regulating the load or load of the cabinet: profile on the basis of the Hm or coating amount or profile of the Hm or: ';': the coating amount. 7. Film transfer coating device according to claim 5, characterized in that the scab is a smooth surface rod.