Method for simultaneous plasma edge encapsulation of at least two adhesive tape sides

Abstract

The invention relates to a method for plasma treatment of at least one surface, wherein a plasma stream (7a) is guided from a plasma nozzle (1) and at least one surface is disposed outside a stream-directionally extended opening cross section of an opening (21) in the plasma nozzle (1), and the plasma stream (7a) is diverted onto the at least one surface.

Claims

1. A method for plasma treatment of at least one surface, wherein a plasma stream is guided from a plasma nozzle and at least one surface is disposed outside a stream-directionally extended opening cross section of an opening in the plasma nozzle, and the plasma stream is diverted onto the at least one surface.

2. The method according to claim 1, the plasma stream emerging from the opening is diverted at a baffle and the at least one surface is disposed transversely to the cross-sectional area of the opening.

3. The method according to claim 1, the plasma stream is parted at a baffle and the parted plasma streams are diverted simultaneously into different directions and each of the parted plasma streams is steered onto a different surface.

4. The method according to claim 1, wherein an adhesive tape having a layer of adhesive is used which comprises at least one adhesive tape side, the adhesive tape side is disposed perpendicularly to the cross-sectional area of the opening and plasma treatment is performed.

5. The method according to claim 1, wherein the adhesive tape has two sides and the two adhesive tape sides are treated simultaneously with plasma.

6. The method according to claim 1, wherein the adhesive tape having two adhesive tape sides is disposed between two plasma nozzles and each of the two adhesive tape sides of the adhesive tape is disposed in each case outside both stream-directionally extended opening cross sections of the plasma nozzles.

7. The method according to claim 1, wherein the adhesive tape side has pressure-sensitive tack and the plasma stream applies a passivation coat to the adhesive tape side.

8. The method according to claim 1, wherein the adhesive tape is used with one adhesive side and two adhesive tape sides, and one adhesive side of the adhesive tape is lined, and only the adhesive tape sides are passivated.

9. The according to claim 1, wherein the at least one surface is covered with an SiOx coating.

10. An arrangement having at least one surface and a device for the plasma treatment of the at least one surface with a plasma nozzle having an opening with an opening cross section, wherein the at least one surface is disposed outside a flow-directionally extended opening cross section of the plasma nozzle and a baffle is disposed in front of the opening in such a way that a plasma stream is diverted at least partly onto the at least one surface.

11. The arrangement according to claim 10, wherein the baffle parts the plasma stream and different parted plasma streams are directed onto different surfaces.

12. The arrangement according to claim 10, wherein the opening is circular and has a diameter of 4 mm.

Description

[0057] The invention is described by means of an exemplary embodiment in two figures, of which

[0058] FIG. 1 shows a frontal view of an arrangement according to the invention for the simultaneous passivation of two adhesive tape sides, and

[0059] FIG. 2 shows a perspective view of the arrangement in FIG. 1.

[0060] FIG. 1 shows a plasma nozzle 1. The plasma nozzle 1 comprises a precursor unit 2, which in FIG. 1 is shown on the left, and a plasma unit 3, which in FIG. 1 is shown on the right. The precursor unit 2 generates a carrier gas 6 enriched with a precursor 4, while the plasma unit 3 generates a plasma 7. The precursor 4 and the plasma 7 are merged in a nozzle head 8.

[0061] The plasma 7 here is a high-energy process gas 11, more particularly ionized air. To generate the plasma 7, the plasma unit 3 is first supplied through an inlet 9 with the process gas 11. The process gas 11 is introduced through the inlet 9 into the plasma unit 3 and passes, through a plate 12 with drilled holes, into a discharge zone 13, through which the process gas 11 flows. In the discharge zone 13, the process gas 11 is conveyed past an electrode tip 14, to which a high-frequency alternating voltage of several kilovolts with a frequency of around 10 kilohertz is connected. Between the electrode tip 14 and a counter-electrode, which may for example be an earthed stainless steel housing 16, a strong alternating electrical field is formed that leads to a corona discharge, which ionizes the process gas 11 flowing through the plasma unit 3 past the electrode tip 14, and converts it into a plasma stream 7a. The plasma 7 is guided through the nozzle head 8, to which the precursor unit 2 is connected at a side inlet 17. The side inlet 17 of the nozzle head 8 is joined to the precursor unit 2. The precursor unit 2 comprises a first feed for the precursor 4 and a second feed for the carrier gas 6. The carrier gas 6 used here may likewise be air or else nitrogen or else a mixture of air and nitrogen. The precursor 4 is atomized and supplied to the carrier gas 6 in droplet form. The mixture passes into a vaporizer 18, where temperatures above the boiling point of the precursor 4 prevail. The precursor 4 used may be an organic, polyfunctional silane, examples being octyltriethoxysilane (OCS), (3-glycidyloxypropyl)trimethoxysilanes (GLYMO) and hexamethyldisiloxane (HMDSO).

[0062] The precursor 4 used here is hexamethyldisiloxane (HMDSO), which is supplied to the carrier gas 6 in an order of magnitude of 10, 20 or 40 grams per hour. The temperature in the vaporizer 18 is 120 C., in other words above the boiling temperature of HMDSO, which is about 100 C. A precursor gas 19 issuing in the vaporizer 18 is supplied to the nozzle head 8, where it is combined with the plasma; accordingly, together with the plasma 7, the precursor 4 passes out of the plasma nozzle 1 and flows onto a baffle 20. The baffle 20 takes the form here of a planar steel plate. At the steel plate, the plasma stream 7a with the admixed precursor 4 is diverted, and in particular the plasma 7 flows away to the side along the baffle 20. An opening 21 in the plasma nozzle 1 is formed circularly in a cross section perpendicular to the stream direction of the plasma 7, and has a diameter of 4 mm. A cross-sectional area of the opening 21 is disposed horizontally and disposed parallel to the impact face of the baffle 20. A cross-sectional area of the plasma nozzle 1 that is extended in the flow direction of the plasma 7 is therefore cylindrical in form. The extended cross-sectional area is indicated in FIG. 1 and FIG. 2 by means of dashed lines.

[0063] It is essential to the invention here that two adhesive tapes 22, 23 disposed parallel to one another and at a distance from one another are provided, these tapes being disposed laterally adjacent to the extended cross-sectional area of the plasma nozzle 1; in other words, the plasma stream 7a emerging directly from the opening 21 strikes the adhesive tapes 22, 23 not directly; instead, inner adhesive tape sides 22a, 23a of the two adhesive tapes 22, 23 are struck simultaneously by the diverted plasma stream 7a and passivated. In this arrangement, outer adhesive tape sides 22b, 23b of the two adhesive tapes 22, 23 are not passivated.

[0064] The two adhesive tapes 22, 23 each have a carrier film 22c, 23c and also each have a layer 22d, 23d of adhesive, which in FIG. 1 is shown somewhat thicker than is usual. An adhesive side of the layer 22d, 23d of adhesive that is used later on for the actual bonding is lined in each case with a liner 24, 25; the liner 24, 25 protects the adhesive side of the adhesive tape 22, 23 from the emerging and diverted plasma stream 7a. The only sides therefore exposed to the diverted plasma stream 7a are the open-lying inner adhesive tape sides 22a, 23a of the two adhesive tapes 22, 23.

[0065] FIG. 2 shows the arrangement of FIG. 1 in a perspective view. The two simultaneously treated adhesive tapes 22, 23 are wound up to a roll 26 and drawn at a consistent speed over the deflection face of the steel plate. The adhesive tapes here are guided in guides which are not illustrated here; sections of the inner adhesive tape sides 22a, 23a of the two adhesive tapes 22, 23 are treated simultaneously with the plasma stream 7a during the entire time.

[0066] Each of the two adhesive tapes 22, 23 is formed in each case by a carrier film 22c, 23c and a layer 22d, 23d of adhesive. The carrier film 22c, 23c is provided in different widths and in the width provided is coated over the full area with the layer 22d, 23d of adhesive. When the adhesive tape 22, 23 is wound up, the tacky adhesive tape sides 22a, 22b, 23a, 23b of the layer 22d, 23d of adhesive on the adhesive tape 22, 23 lie open. They make it more difficult for the product to be used; they may stick, and foreign particles may become deposited on them.

[0067] The tackiness of the inner adhesive tape sides 22a, 23a is reduced by application of a passivation coat; the passivation coat may be an SiOx coating which is applied over the full area to the inner adhesive tape sides 22a, 23a of the layers 22d, 23d of adhesive on the adhesive tape 22, 23 in a plasma process, using the plasma nozzle 1 shown in FIGS. 1 and 2. In this case, the opening cross section of the plasma nozzle 1 lies perpendicular to the inner adhesive tape sides 22a, 23a of the layers 22d, 23d of adhesive.

[0068] The adhesive may be a pressure-sensitive adhesive, more particularly an acrylic adhesive. The substrate web may be a PET or PE film.

LIST OF REFERENCE SYMBOLS

[0069] 1 Plasma nozzle

[0070] 2 Precursor unit

[0071] 3 Plasma unit

[0072] 4 Precursor

[0073] 6 Carrier gas

[0074] 7 Plasma

[0075] 7a Plasma stream

[0076] 8 Nozzle head

[0077] 9 Inlet

[0078] 11 Process gas

[0079] 12 Plate

[0080] 13 Discharge zone

[0081] 14 Electrode tip

[0082] 16 Earthed stainless steel housing

[0083] 17 Side inlet

[0084] 18 Vaporizer

[0085] 19 Precursor gas

[0086] 20 Baffle

[0087] 21 Opening

[0088] 22 Adhesive tape

[0089] 22a Inner adhesive tape side

[0090] 22b Outer adhesive tape side

[0091] 22c Carrier film

[0092] 22d Layer of adhesive

[0093] 23 Adhesive tape

[0094] 23a Inner adhesive tape side

[0095] 23b Outer adhesive tape side

[0096] 23c Carrier film

[0097] 23d Layer of adhesive

[0098] 24 Liner

[0099] 25 Liner

[0100] 26 Roll