Device for adhesive coating with process-related waste heat

Abstract

Apparatus for adhesive coating. Characterized in that after the adhesive application (3), a laminating station (5) brings together two carrier webs (1) and (4) in an inert chamber (12).

Description

The invention relates to a process for producing a pressure-sensitive adhesive tape, having the following steps: providing a pressure-sensitive adhesive (4) which comprises monomers polymerizable by electromagnetic radiation and a photoinitiator; providing a tape-shaped carrier (1); applying the pressure-sensitive adhesive (3) to at least one of the sides of the carrier (1); and transporting the carrier (1) with the applied pressure-sensitive adhesive through an inert channel (5) filled with nitrogen.supplying and laminating a transparent cover tape (4) transporting the applied pressure-sensitive adhesive with transparent cover tape (4) to the composite and exposing to electromagnetic UV radiation. (10) Whereby the PSA polymerizes.The invention is characterized in that the drying channel (11) has a main section of a water basin (11) filled with water (6) and at least one radiation source (10), wherein the composite is guided through the water basin,The radiation of the radiation source (10) is effected by the water (6) in the water basin (11)Function:EP 4 477 722 A1 discloses a method for producing a pressure-sensitive adhesive bath, in which the applied pressure-sensitive adhesive (14) is exposed to electromagnetic UV radiation (13) in direct water contact (6). The contact with water is intended to create an inert environment and to remove directly the process heat arising from the polymerization. However, in practice, this creates several problems which are as follows.When the web (1) of material with applied pressure-sensitive adhesive (14) is being supplied, corrugations can form in the still soft adhesive surface as a result of the water contact. Likewise, small oxygen bubbles adhere to the adhesive surface, which interfere with the polymerization process. The elements outgassing during the polymerization contaminate the water (6) and basin (11), which leads to considerable cleaning effort and production interruption.The method shown in EP 4 477 722 A1 irradiates the substrate with electromagnetic UV radiation from below through the water basin. This implies that the basin must be at least transparent and has a high transmission rate. This is extremely difficult in practice. Large pools of white glass must be made with a high thickness of glass plates. With the thickness of the glass, the transmission rate of the electromagnetic UV radiation decreases considerably. The alternative of a metal basin with window inserts has the disadvantage of shading at the junctions, this shading stops the polymerization and causes uneven adhesion and or streaking.In most cases, in the production of such pressure-sensitive adhesive tapes, cover tapes (4) are supplied after the polymerization, since the material web handling with open adhesive is technically complicated.The present invention solves the known problems as follows.A pressure-sensitive adhesive (13) is applied to the carrier tape (4) by means of, for example, a nozzle (3), but this can also alternatively be effected by alternative application methods customary on the market. After the pressure-sensitive adhesive (13) has been applied by the applicator (3), the pressure-sensitive adhesive (14) is covered by a covering tape (1) which has been supplied before the polymerization. The covering tape (1), which is preferably transparent and has UV transmission, is preferably supplied under inert conditions and a station (5) laminates the pressure sensitive adhesive (13) with the exclusion of oxygen.This is preferably effected after the adhesive application ( 3) in a downstream nitrogen-flooded chamber ( 12) which seals off at the outlet below the water surface ( 6) at the bottom.Alternatively, the pressure sensitive adhesive (13) applied to the carrier web (4) can be prepolymerized by an electromagnetic radiation source (17) before being laminated to the station (5). This reduces the flow properties of the pressure sensitive adhesive and increases the application quality.The composite of carrier web with covered pressure sensitive adhesive (4+14+2) is fed to a water bath (11). An electromagnetic radiation source (13) initiates polymerization. The water bath (11) has a laminar flow in the transport direction. A circulatory system (10) with a pump draws off the water (6) below the water line at the tank end (15) and returns it at the tank beginning (16) below the water line (6). The waste heat introduced by the polymerization can be discharged via heat exchangers ( 10). The water can likewise be filtered and chemically processed via a filter system ( 10), as is state of the art in commercial pool technology.This invention avoids the existing technical problems, such as water pollution caused by outgassing during polymerization. Chemical reactions with the water are likewise prevented by covering with film. Finally, the structural design of the water basin is much simpler to design. Since this no longer has to be transparent. The electromagnetic radiation source can act on the floating substrate from above, while the water absorbs and removes the heat of reaction.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 4 477 722 A1 [0005, 0007]

Claims

Device for adhesive coating, characterised in that after the adhesive application (3) a laminating station (5) joins two carrier webs (1) and (4) in an inert chamber (12)Device according to claim 1 characterised in that prior to lamination to (5), prepolymerisation by an electromagnetic radiation source (17) prepolymerises the pressure sensitive adhesive (14).Device according to claim 1 characterised in that the laminated composite (4+14+2) is fed to a water bath.Device according to claim 1 characterised in that an electromagnetic radiation source (13) can act on the substrate selectively from above above the water line or from below below the water line.The apparatus of claim 1 characterized in that the water band receives the process heat and has a laminar flow through a circulatory system.Device according to claim 1 characterised in that an air nozzle (8) blows off the adhering water at the outlet of the basin.

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