FI117106B - Method and apparatus for transferring a substance to a fiber web - Google Patents

Description

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Method and apparatus for transferring material to a fibrous web

The present invention relates to a method and apparatus for transferring material to a fibrous web by a processing device having at least one fibrous web treatment 5 such as a belt or roll or similar support surface and a tactile zone forming a fibrous web.

In many known commonly used coating and surface sizing processes, the material to be transferred is applied directly to the surface of a paper or board web. In spray coating, the coating is sprayed as a fine mist in a direct curtain coating and in a jet coating, the coating paste is applied to a thin web or film directly onto a web. ).

A common feature of the above-mentioned methods is that the methods are i 20 coating methods. The material to be transferred is applied to the fibrous web as a wet: sion or slurry, and the coated fibrous web must be dried after application: instead of the so-called. in the dry coating process, the substance applied to the fibrous web is in powder form. Applicability is accomplished by reserving the material to be added ** * • electronically and controlling the material flow of the application event i

Ml * 25 inches on a movable surface using an electric field. Applied layer of ori. ···. secured by a hot pressing nip. Its place; no drying of the tufted fiber web is required.

The general object of the present invention is to provide an improved and .... . ... ...... . . . __. _ ____ ... * ...

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Another key objective is to improve the adhesion of the aprotic substance s and to the surface of the fibrous web by raising the heat of the material to be transferred, softening, fluidizing, and penetrating into the fibrous web. In this regard, one objective of the invention is to provide a simple and highly efficient technical solution for heating the substance to be transferred in the context of an appiil. A third central objective is to enhance the adhesion of the graft material to the fibrous web by following a bonding event where the material is in compression contact with the fibrous web to allow the heated and softened material to flow and penetrate into the porous 10 of the fibrous web.

To achieve the above objectives, the invention is characterized in that the method utilizes at least a support surface of the processing device as a transfer surface for contacting the transferable material j with the fibrous web prior to contacting the transfer web with the mc screen surface to preheat the material to be contacted. The fold according to the invention is characterized in that the support surface of the at least one processing member of the device is to act as a transfer surface to which the material to be transferred to the fibrous web is guided prior to contacting the surface with the fibrous web and is arranged to preheat the material to be heated. with a fibrous web.

• · • · * · «• · i. ·; In the method according to the invention, the substance to be transferred is first applied to the transfer surface, which is introduced into the transfer zone for contact with the spindle of the fibrous web: the applied substance is transferred from the transfer surface to the surface of the fibrous web. Thus, the transfer zone is formed from the common contact area between the transfer surface and the fibrous web, to which or * * · material is carried by the transfer surface and from which the fibrous web leaves the apical «» · ». * ··. transporting the surface. In particular, the transfer surface may be with a fibrous web 3 3

Thus, in the method of the invention, the surface forming the fibrous web in the transfer zone is used as the transfer surface on which the substance to be transferred c is contacted and transferred to the fiber at the latest in the bridging zone. The transfer surface is heated such that the substance to be transferred to the resin 5 is heated prior to contact with I, whereby the substance to be transferred is heated during transfer in the zirconia zone to the surface of the fiber web. Due to the preheating, the transferable material is more easily penetrated into the pores of the fibrous web and adheres to the fibrous web by paralyzed attachment to the surface of the fibrous web and by the heat and compression of the transferable material in the transfer nip.

The solution according to the invention is particularly advantageous when the dry coating applied with the dry coating is heated even before the fixing nip, whereby the main function of sealing the applied substance remains with the fixing nip jc 15 the fixing nip can be dimensioned especially for the heat transfer.

The solution according to the invention is also suitable for application other than dry coating. The material to be transferred may be in the form of a wet mixture in the form of a paste-like slurry or suspension, or in dry form, for example as a powder; . The substance may be a coating agent, a plasticizer, a solution chemical, and the like.

In the following, the invention will be described in more detail with reference to the accompanying drawings: * 25: FIG. 1 schematically illustrates one embodiment of the invention in connection with a tob-belt conveyor, FIG. 2 schematically illustrates another embodiment. rc 4 according to the invention

Figure 4 schematically shows a fourth solution according to the invention when applied in connection,

Figure 5 schematically illustrates a fifth embodiment of the invention

Figure 6 schematically illustrates a sixth embodiment of the invention.

The various embodiments of the invention will now be described by way of example with reference to Figures 10. Figure 1 illustrates an apparatus arrangement according to the invention comprising a main metal belt loop 2 and an outer support surface va 5 between which a fiber web W is guided. The belt 2 and the roller meet an elongated treatment area N, the tension of which on the fibrous web can be controlled by the tension of the belt 2 and by the possible loading of an additional support roll 4 inside the rotation.

In the embodiment of Fig. 1, the substance 13 to be added is dispensed onto the support surface, either by the applicator 11 on the belt 2 or by the applicator 11 'on the surface of the roll 5. The application can also be performed on both surfaces 20 strips.

In the embodiment of Figure 1, at least one supporting surface, either met: * * *: or roll 5, is arranged to be heated. The metal belt can be heated by its heating means 6, such as an induction heater, infra · * · * · :. 25 burners or gas burners. Heating can also be based on resistive drying · *. its. The heating may also be effected by means of the heating brackets to be heated. "*» Can be arranged to be heated, for example, by conventional means of heating a thermal roller. If necessary, a scraping system or similar cleaning system 7, T is provided in connection with the support surfaces, whereby the support surface is prepared. and / or the roller 5 is equipped with a ground rod (not shown), so that the transferable substance p exiting the picking device is prepared with sufficient potential difference with respect to the transfer surface 2, 5. As they come into contact with the heated transfer surface 5, they heat up before contacting the fiber web. is preferably arranged to come into contact with the fibrous web in a sufficiently long treatment area between the belt j so that in the treatment area the k is subjected to a heating and compression effect which allows the movable to be permanently applied to the surface of the fibrous web.

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Particularly preferably, the substance to be transferred is a dry powdered substance, mainly pi, and a binder or polymer mixture used for pigment or barrier dry coating. Instead of the particulate fiber, a solution, a finely divided slurry, a paste or other wet mixture may also be applied. In addition to a pigment and binder blend of a curing agent, the agent may, e.g., a sizing agent, a solution; chemical, water or the like.

In addition to the method described above for utilizing the electric charge field, the transfer agent may be delivered to the transfer surface by other t: principles such as brushing, spraying, draining or contacting, and in particular by applying n: [[[such as spray coating, blade coating, spray coating: application, etc.

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Preferably, the transfer surface is scraped or cleaned using a transfer device 7, T after the transfer nipple, before re-dispensing agent can be applied to the surface during circulation to apply an anti-adhering chemical.

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Fig. 3 illustrates an embodiment of the invention in which two rollers 5.5 'm are interposed between the nip or processing zone through which the fiber web W is passed, i the zone loading can be controlled by the roll load and temperature s. Applicators 11.1Γ. The application can be made to either of the surfaces 5, 5 'or both at the same time. At least one of the support surfaces is heated so that the applied substance is heated before contact with the fibrous web W in the transfer zone. The rolls are heated by arrangements known per se. The rollers are cleaned by means of the apparatus 10 before being dosed again.

Figure 4 shows an embodiment in which the aprotic agent 13 is, for example, a powder coating composition in the form of a pigment and a binder in powder form. In the exemplary embodiment of Figure 4, electrodes 21 are provided at the mouth 12 of the apical 15 when the particles 13 are charged when exiting the applicator. The roll 15 is connected to the ground electrode 10 and at the same time the transfer surface on which the charged pair exiting the applicator 12 is first contacted The transfer roll 15 is then introduced on its surface into contact with the fibrous web W on the surface of the transfer web 20. The contact preferably takes place with the counter roll 16 to form # #; on the roll nip N (area II) or shortly before (area I). The roll 15 is a heater: The particles 13 created before the contact I or II are heated, where the top attachment takes place by the compression and the li: effect on the web N.

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Fig. 5 illustrates a very simple embodiment of the invention which: * only the contact of the heated roll 5 and its outer surface:. W. Applicator 11 dispenses additive into support and transfer coating. ** ·. The surface of the van roll where the substance to be transferred is heated and from which the substance is transferred Foam 7 does not require particularly good heat transfer contact. In this embodiment, it is also advantageous, for example, in the case of dry coating, to use substances with a low transition temperature Tg, e.g. of the order of 20-100 ° C.

Fig. 6 shows an embodiment in which the aprotic material is transferred using a spiked field W onto a fibrous web W by an applicator 12. Electrodes 21 are provided in the aperture of the aperture 12 upon discharge of the particles 13 from the applicator. The roller 15 is connected to the ground electrode 10 and r at the same time a contact surface on which the charged par 10 discharged from the applicator 12 first contacts. The transfer surface roll 15 is then introduced on its surface with the particles in contact with the fibrous web W to transfer the particles to the surface of the web. The supporting surface, in this example a thermo roll 15, is a heated material applied before being contacted in the w k <zone of the fibrous web. Here, the pressure acting on the contact is again due to the tension of the web only in the embodiment 15. Since the contact pressure is very low, and thus the transfer is modest, it is advantageous in this embodiment to use a transferable dry coating, for example, which requires a low temperature treatment. Particularly, a dry coating material having a glass transition temperature Tg of the order of 20-100 ° C is used.

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** Y The invention has been described above by way of example, with reference to Figures 1-6. I

With reference to * * · leather, reference has been made to a metal belt solution where steel belts are particularly preferred. However, other meta straps, and j <: ·: # ϊ metal straps and wires are possible. For example, drier or other fabric reinforced polymer wires with sufficient surface: * * * work is contemplated where appropriate.

The invention is particularly suitable for coating paper and board fiber webs for sizing and wetting in connection with a production line.

Claims (12)

A method for transferring a coating and / or treating agent on a paper / carton (W) processing device having a support surface of at least one processing member (5, 2,15) r 5, with which the web to be treated is contacted with at least one of the processing means. (2,5,15) the support surface is used as a surface on which the substance (13) to be conveyed to the web (W) is conveyed prior to transfer to contact with the web, characterized in that said transfer is heated to preheat the conveyed substance before contacting it. Method according to claim 1, characterized in that the transfer is made in contact with the fibrous web in a nip or in a treatment area (N). Process according to Claim 1 or 2, characterized in that the substance is present in the form of a wet paste, suspension or solution or mist in the form of a spray on the transfer surface. A process according to claim 3, characterized in that the fibers 20 are water or a water-soluble chemical. * »* · ♦: Method according to claim 3 or 4, characterized in that the method is selected from the group consisting of: blade coating, film transfer coating, sp • * / ·; coating, curtain coating, casting. The process according to claim 1 or 2, characterized in that the substance is in the form of a dry powder or powder when applied to the transfer surface. M varaus φ φ · yhtenä · • M M M käyttäen M käyttäen toimii toimii yhtenä M M M M M M käyttäen M M M M M M M M M M M M M M M M M M M M M M M käyttäen käyttäen thus, the 5 known particles (13a) contact the transfer surface. Method according to one of Claims 1 to 8, characterized in that the wrapping device has a belt rotation (2) arranged to rotate around at least one support member (3) and at least one non-belt rotating counter member (5), which provides an area for processing the fibrous web. A method according to any one of claims 1 to 8, characterized in the slit processing device being a nip formed by two opposing rolls. A method according to any one of claims 1 to 8, characterized in that the dressing device has an area for forming a contact between a single roll and a fibrous web. A method according to any one of claims 1 to 11, characterized in that material is transferred to both surfaces of the fibrous web simultaneously. 9 Φ 9 9 9: *:: 13. A method according to any one of claims 1 to 11, characterized in that the material is transferred only to one surface of the fibrous web. · 9 9 9: 25 14 Method according to any one of the preceding claims, characterized in that the processing device performs, in addition to filing the fiber n 9 9 ***** of the material to be transferred to the fibrous web, a calendering treatment of the fibrous web in a nip or a processing area 9 9 9 9 9: *: for transferring the coating and / or treating agent, the paper / board stock is arranged to be heated to preheat the transferable agent to the delivery press contact with the web. Apparatus according to claim 15, characterized in that each of said metal belt turns (5; 20) is arranged to rotate about one of the support members (3), which forms a processing area of the fibrous web extended with a hi hi. Device according to Claim 15, characterized in that a nip formed by 10 opposing rolls (5, 5 '; 15,16). Apparatus according to claim 15, characterized in that there is a ki (5; 15) which forms a contact with the fibrous web (W). Device according to one of Claims 15 to 18, characterized in that the device (15) is arranged to act as an electrode and that the device comprises at least one second electrode (21) arranged on the path of the fluxing material and the material particles (13) thereof being chargeable. with sufficient charge potential to form with respect to the electrode such that the charged particles (13a) are deposited on the transfer surface using an electric charge field. ♦ »♦ · •» • t · · •>> 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 4 4 4 4 4 4 4 4 4 444 4 Λ Λ Λ