DE102018203276A1 - indicator Tape - Google Patents

Abstract

The invention relates to the use of an adhesive tape comprising at least one preferably reversibly adjusted PSA layer, at least one getter material which exhibits a change in optical properties upon permeate pickup, and optionally a carrier film which preferably has a water vapor permeation rate <1 g / m ² d for the detection of Defects, in particular pinholes, in a barrier film, wherein the barrier film has at least one barrier layer and optionally a carrier layer. Likewise, the invention relates to a method for detecting defects in a barrier film, in which such an indicator tape is used, as well as a composite of a barrier film and such an indicator tape.

Description

The present invention relates to a method for detecting defects such as pinholes in a barrier film, wherein the barrier film has at least one barrier layer and optionally a carrier layer, by means of an adhesive tape, comprising at least one preferably reversibly adjusted pressure-sensitive adhesive layer and at least one getter material, the change in the permeate optical properties, the use of such an adhesive tape for the detection of defects in a barrier film as well as a composite of such an adhesive tape and a barrier film.

(Opto) electronic devices are increasingly used in commercial products. Such arrangements include inorganic or organic electronic structures, such as organic, organometallic or polymeric semiconductors or combinations thereof. These arrangements and products are rigid or flexible depending on the desired application, whereby there is an increasing demand for flexible arrangements. The production of such arrangements is effected for example by printing processes such as high-pressure, intaglio, screen printing, planographic printing or as well as so-called "non-impact printing" such as thermal transfer inkjet printing or digital printing. In many cases, however, vacuum processes such as chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma-enhanced chemical or physical deposition (PECVD), sputtering, (plasma) etching or vapor deposition are used, the patterning usually by masks he follows.

Electrophoretic or electrochromic structures or displays, organic or polymeric light-emitting diodes (OLEDs or PLEDs) in display and display devices or as lighting, electroluminescent lamps, are examples of commercial (or optoelectronic) applications that are already commercially attractive. light-emitting electrochemical cells (LEECs), organic solar cells, preferably dye or polymer solar cells, inorganic solar cells, preferably thin-film solar cells, in particular based on silicon, germanium, copper, indium and selenium, organic field effect transistors, organic switching elements, organic optical amplifiers, organic Laser diodes, organic or inorganic sensors or organically or inorganic-based RFID transponder listed.

Accordingly, in this document an organic (opto) electronic arrangement is understood to mean an electronic arrangement which comprises at least one electronically functional, at least partially organic constituent - for example organometallic compounds - or whose electronically functional structure has a thickness of less than 20 μm.

As a technical challenge for the realization of sufficient life and function of (opto) electronic arrangements in the field of inorganic and / or organic (opto) electronics, but especially in the field of organic (opto) electronics is a protection of the components contained therein to see before permeates. Permeates may be a variety of low molecular weight organic or inorganic compounds, especially water vapor and oxygen.

A variety of (opto) electronic arrangements in the field of inorganic and / or organic (opto) electronics, especially when using organic raw materials, is sensitive to both water vapor and oxygen, for many arrangements, the penetration of water or Water vapor is classified as a major problem. Therefore, encapsulation protection is required during the lifetime of the electronic device, otherwise performance will degrade over the period of use. Thus, for example, by an oxidation of the components such as in light-emitting devices such as electroluminescent lamps (EL lamps) or organic light-emitting diodes (OLED), the luminosity, in electrophoretic displays (EP displays) the contrast or in solar cells efficiency within a very short time to decrease.

In addition to glass, barrier films for flexible use and production can be used for encapsulating moisture-sensitive organic electronics. These films usually consist of a polymer film as a carrier and one or more organic or inorganic barrier layers. Regardless of the fabrication of these barrier layers (eg, vacuum deposition or atmospheric pressure deposition), these are typically flawed in the current art. For example, they have scratches, cracks or pinholes. Defects due to surface defects or defects in the deposition process are referred to as so-called "pinholes," that is, small holes that are generally invisible to the eye or many optical inspection systems. Through these pinholes, water can diffuse through the film almost unhindered in later use. Punctual defects up to total failure of the sensitive component are the result. Due to the small size of the pinholes, it is not possible to detect these before use with conventional optical, usually camera-based, detection systems for defects in films. By "defects" of a barrier film in the context of the present application is typically meant those sites of a barrier film through which water can diffuse substantially unhindered through the film.

In the field of barrier films or barrier tapes for encapsulating water-sensitive organic electronics, the use of getter materials is therefore customary. These getters may be particulately dispersed in an adhesive or otherwise located anywhere in the assembly of such electronics. They serve to intercept and bind Permeate. Some of these materials may be altered by a change in color or the like. show a reaction with water. For example, the DE 10 2012 211 335 A1 the protection of an (opto) electronic arrangement by means of a cover, wherein this cover is glued to an adhesive which contains as getter material particularly preferably calcium oxide, metallic calcium or cobalt chloride. These getter materials are preferred because they change their optical properties upon incorporation of the permeate, so that conclusions can be drawn about the content of permeate already incorporated in the adhesive. However, these are not reversible structures. The adhesive is used for permanent fixation of the barrier film on the electronics to be protected. Other getter materials that indicate a color change reaction with permeate, for example, in US 6,936,131 B1 , the US 2010/0272933 A1 , the EP 1 407 818 A1 or the US 9,548,473 B2 described.

US 2012/0164434 A1 describes a multi-layer barrier film which, in addition to at least one barrier layer, also has a leveling layer for leveling imperfections. In order to test the quality of the barrier film for the presence of defects, a test arrangement is disclosed in which a thin layer of calcium is used as a detection surface for pinholes in a test piece of the film to be examined. An investigation of the entire film on Pinholes is not possible with this structure.

A reversible structure of a laminate of barrier film and adhesive tape discloses the DE 10 2012 224 319 A1 , Here, the getter material-containing adhesive tape serves to remove permeate from the barrier film. Preferred getter materials include calcium oxide, metallic calcium, iron, barium lithium chloride and cobalt chloride, which permit conclusions to be drawn as to the permeate content of the barrier film to be liberated from permeate by changing their optical properties. In this case, the adhesive tape is glued to the carrier film of the barrier film, ie on the side which is furthest away from the barrier layer. The aim of this disclosure is the removal of permeate from the barrier film or from the protected by this electronics. The discoloration of the getter material indicates the progress of permeate uptake. A recognition of any defects in the barrier film or even their location is not mentioned in the document.

It was therefore an object of the present invention to provide a simplified solution for identifying defects such as pinholes in barrier films, which allows control of the entire film surface and advantageously discloses the position of each defect.

• - Herstellen eines im Wesentlichen vollflächigen Verbundes des Klebebands und der Barrierefolie;
• - Lagerung des Verbunds in vorzugsweise feucht-warmem Klima;
• - Detektion der optischen Änderung des Gettermaterials;
• - optional Markierung der durch die optische Änderung des Gettermaterials angezeigten Fehlstellen in der Barrierefolie; und
• - Ablösen des Klebebands von der Barrierefolie.

This object is achieved by a method for detecting defects, in particular pinholes, in a barrier film, wherein the barrier film has at least one barrier layer and optionally a carrier layer comprising, by means of an adhesive tape, preferably at least one preferably reversibly adjusted PSA layer, at least one getter material , which exhibits a change in the optical properties upon permeate absorption, and optionally a carrier film which preferably has a water vapor permeation rate (WVTR) <1 g / m ² d, characterized in that the method comprises the following steps:

• - Producing a substantially full-surface composite of the adhesive tape and the barrier film;
• - Storage of the composite in preferably humid-warm climate;
• - Detecting the optical change of the getter material;
• optionally marking the defects in the barrier film indicated by the optical change of the getter material; and
• - Removal of the adhesive tape from the barrier film.

The method preferably does not include any further steps.

The adhesive tape used according to the invention is also referred to as indicator adhesive tape or indicator tape in accordance with its function.

The surfaces of the adhesive tape and of the barrier film are therefore in direct contact in the process according to the invention, the adhesive tape being in contact with the barrier film via the pressure-sensitive adhesive layer. In a preferred embodiment, the composite of the adhesive tape and the barrier film is produced by laminating the adhesive tape to the barrier film.

The adhesive tape has a pressure-sensitive adhesive layer for fixing on the barrier film. Generally, a distinction is made between pressure-sensitive adhesive layers for permanent applications and for reversible applications (reversibly set PSA layers). While the former usually only with great effort and often with destruction of the substrate or the adhesive tape can be replaced again, the latter can be replaced with relatively little effort and without destroying the primer usually completely residue-free again. According to the invention, the pressure-sensitive adhesive layer of the adhesive tape applied to the barrier film is preferably set reversibly.

The reversibility of a pressure-sensitive adhesive layer can be described by means of its viscoelastic properties.

A substance with respect to its viscoelastic properties is generally considered to be suitable for pressure-sensitive adhesive applications, if at room temperature in the frequency range of 10 ° to 10 ¹ rad / s, ideally in the frequency range of 10 ^-1 to 10 ² rad / s, the storage modulus G 'in the range from 10 ³ to 10 ⁶ Pa and if the loss modulus G "also lies in this range Within this range, which is also applied in a matrix plot of G 'and G"(G' as a function of G ") as viscoelastic For pressure-sensitive adhesive applications or as a pressure-sensitive adhesive window according to viscoelastic criteria, there are again different sectors or quadrants which further characterize the expected pressure-sensitive adhesive properties of the respectively associated substances. "According to Chang (J. Adhesion, 1991, volume 34, pp. 189-200 ) are reversible PSAs by G 'in the range of 10 ³ - 3 × 10 ⁴ Pa and G "in the range of 10 ³ - 3 × 10 ⁴ Pa each at room temperature r and a measuring frequency of 10 ^-2 rad / s. Storage modulus and loss modulus for PSAs are determined here in the oscillatory shear experiment (dynamic mechanical analysis, DMA) under torsional stress at a temperature of 23 ° C. and a frequency of 0.01 rad / s. The test serves to investigate rheological properties and is described in Pahl et al. "Practical rheology of plastics and elastomers", VDI-Verlag, 1995, pages 57 to 60 and 119 to 127) described in detail. The test is run in a shear rate controlled rheometer under torsional loading using a plate-plate geometry with a plate diameter of 25mm.

According to the invention, a pressure-sensitive adhesive layer is generally regarded as reversibly adjusted when the pressure-sensitive adhesive layer leads to an adhesive force of the inventive adhesive tape containing float glass of <1 N / cm, preferably of <0.5 N / cm, determined at 23 ° C./50 % relative humidity at a peel angle of 180 ° and a peel rate of 300 mm / min (as indicated in the measurement method section).

In reversibly adjusted pressure-sensitive adhesive layers, it is possible according to the invention in particular to use all adhesive-mass systems which are based on silicones, acrylates, epoxides, natural rubber or synthetic rubber. Preferred types are base polymers which have a water vapor permeation rate, WVTR, measured at 38 ° C / 90% relative humidity of <500 g / m ² d. Particularly preferred are those having a WVTR <100 g / m ² d, in each case based on a layer thickness of 50 microns. A low WVTR of the pressure-sensitive adhesive reduces lateral diffusion of permeate from the environment through the cross-section into the adhesive layer and thus premature consumption of getter material. According to the invention, particularly preferred pressure-sensitive adhesive layers based on vinylaromatic block copolymer, such as styrene block copolymer, are used, for example SEBS block copolymer.

A "getter material" is understood according to the invention to mean a substance which is capable of taking up (sorbing) one or more permeable substance (s). The sorption of the permeable substance (s) by the getter material can be effected for example by absorption or adsorption, wherein adsorption can occur both in the form of chemisorption and physisorption. The getter material could therefore also be referred to as a "sorbent" or as a "sorbent". It can be contained as a full-surface layer or as a disperse phase in the adhesive tape construction.

Typically, in the process of the invention, the permeate is water and the getter material is a desiccant. At least one substance selected from the group consisting of calcium oxide, calcium, iron, barium, lithium chloride and cobalt chloride is preferably used as the getter material.

The optional storage of the composite in a humid and warm climate ensures that water (vapor) is present, which can pass through any imperfections such as pinholes in the barrier film. The penetration of water (steam) is accelerated in this way. But there is also the possibility that water is contained in the barrier film itself. Although this water contained in the barrier film diffuses therefrom through the voids such as pinholes into the getter material, a reaction occurs which causes a change in the optical properties of the getter material. This allows the use of the method according to the invention even when wound on the roll barrier films in which the access of external moisture is hindered to the layers on the roll. In a preferred embodiment, therefore, the process is used in roll-wound laminates of barrier film and adhesive adhesive tape.

Moist and warm climate here means a temperature and a relative humidity that is above 23 ° C and 50% relative humidity. Preferably, the climate is above 35 ° C and above 70% relative humidity, for example in the range of 38 ° C and 90% relative humidity, 60 ° C and 90% relative humidity or 85 ° C and 85% relative humidity.

The preferred storage time depends on the storage conditions, in particular the relative humidity and the temperature. The higher the temperature and / or the relative humidity, the shorter the storage times are typically required. For example, it may be stored at 85 ° C and 85% relative humidity overnight, typically for at least 8 hours.

In a preferred embodiment, in addition to the at least one pressure-sensitive adhesive layer, the adhesive tape has at least one layer containing the at least one getter material, i. Indicator layer, on. In a further preferred embodiment, the pressure-sensitive adhesive layer of the adhesive tape contains the at least one getter material.

If the barrier layer is an outer layer of the barrier film, the adhesive tape in the produced composite of the adhesive tape and the barrier film is preferably arranged on the barrier layer of the barrier film or, if the barrier layer is not an outer layer of the barrier film, arranged on the surface of the barrier film closest to the barrier layer ,

The barrier layer may be an inorganic or an organic barrier layer. Typically, the barrier layer is an inorganic barrier layer, preferably selected from deposited metals, such as in particular aluminum, silver, gold and nickel, and (semi-) metal oxides, nitrides and hydronitrides, in particular oxides and nitrides of silicon, boron, aluminum , zirconium, hafnium and tellurium or indium tin oxide.

Furthermore, the object underlying the invention is achieved by the use of an adhesive tape comprising at least one preferably reversibly adjusted PSA layer, at least one getter material which shows a change in the optical properties upon permeate pickup, and optionally a carrier film which preferably has a WVTR <1 g / m ² d has for detecting defects such as pinholes in a barrier film, wherein the barrier film has at least one barrier layer and optionally a carrier layer. The barrier layer may be inorganic or organic, preferably it is inorganic. The adhesive tape thus becomes the adhesive tape or indicator tape, which is reversibly connected to the barrier film and makes defects in the barrier film visible. This makes it possible to pick out areas of barrier films that are defect-free and to use only those film sections for covering electronic components. Thus, the quality of (opto) electronic components can be significantly improved.

The surfaces of the adhesive tape and of the barrier film are thus brought into direct contact, as in the process according to the invention, even in the case of the described use, the adhesive tape being brought into contact with the barrier film via the pressure-sensitive adhesive layer.

Finally, the present invention relates to a composite of a barrier film, wherein the barrier film has at least one barrier layer and optionally a carrier layer, and an adhesive tape comprising at least one typically reversibly adjusted pressure-sensitive adhesive layer, at least one getter material, which shows a change in the optical properties on permeate absorption, and optionally a Carrier film, which preferably has a WVTR <1 g / m ² d, wherein the composite is substantially full-surface. The barrier layer may be inorganic or organic, preferably it is inorganic.

In combination, the surfaces of the adhesive tape and the barrier film are in direct contact, wherein the adhesive tape is in contact with the barrier film via the pressure-sensitive adhesive layer.

Advantageously, a carrier foil with a WVTR <1 g / m ² d is contained in the indicator adhesive tape construction, since otherwise there is the danger that moisture will enter the getter material from the side of the carrier foil. Particularly preferably, the carrier film has a WVTR which is less than the WVTR of the barrier film. Most preferably, the carrier foil is a metal foil, for example an aluminum foil.

According to the invention it is thus possible, e.g. so-called Pinholes in a barrier film to detect, to mark on request and to select based on the knowledge gained certain areas of the barrier film, which have no defects and thus to allow reliable protection of electronic, especially with organic components. As described above, gas-permeable microdefects in barrier layers, often caused by surface defects, are referred to as pinholes. Lateral diffusion of oxygen and water through pinholes, cracks or scratches in the barrier layer leads to a significant reduction in the barrier effect of a barrier film.

In an advantageous embodiment of the invention, as already described above, the adhesive tape has, in addition to the at least one typically reversibly adjusted pressure-sensitive adhesive layer, at least one layer containing the at least one getter material, i. Indicator layer, on. This design has the advantage that no special requirements are imposed on the getter material with regard to the PSA, in particular the compatibility of getter material and PSA. If such an adhesive tape contains a carrier film, the indicator layer is typically arranged between the carrier film and the pressure-sensitive adhesive layer.

In a further advantageous embodiment, the pressure-sensitive adhesive layer of the adhesive tape has the at least one getter material. In this case, a particularly compact construction of the adhesive tape is possible, because in addition to the optional carrier film only one more layer is required. If such an adhesive tape contains a carrier film, the getter material-containing pressure-sensitive adhesive layer is typically arranged directly on the carrier film.

Particularly suitable are the use, methods and composite of the present invention for water as permeate, as getter a desiccant is used.

The indicator tape may include a getter material or a combination of several getter materials. It is only necessary to ensure that a sufficiently detectable change in the optical properties of the getter material occurs when it comes in contact with permeate.

Preferably, the getter material is at least one substance selected from the group consisting of calcium oxide, calcium, iron, barium, lithium chloride and cobalt chloride. in question. By means of a change in their optical properties, these substances allow conclusions to be drawn about diffused permeate from the barrier film. As long as free getter capacity can still be detected on the basis of the optical appearance of the adhesive tape, this can be taken as an indication that no or at most only a small amount of permeate has diffused through the barrier film to be examined. As a change in the optical properties, a color change or a change in the transparency is preferred, in particular a change perceptible to the human eye. The change of the optical properties is preferred by means of technical aids, e.g. a microscope, a camera or a spectrometer detected. For example, metallic calcium loses its metallic-opaque appearance upon reaction with water and becomes increasingly transparent. Cobalt chloride changes color from blue to pink on water uptake. Calcium oxide loses its white color with water absorption and becomes transparent.

A barrier layer, as used in the barrier film according to the invention, can consist of organic or inorganic materials, for example of a metal layer or an organic layer or a sol-gel layer. The barrier film may have one or more barrier layers.

At least one barrier layer of the barrier film is preferably an inorganic barrier layer. As inorganic barrier layers are particularly well in a vacuum (for example by evaporation, CVD (chemical vapor deposition), PVD (physical vapor deposition), plasma enhanced chemical vapor deposition (PECVD)) or metals deposited under atmospheric pressure (for example by means of atmospheric plasma, reactive corona discharge or flame pyrolysis), such as aluminum, silver, gold, nickel or in particular (semi-) metal compounds such as (semi-) metal oxides, nitrides or hydronitrides, for example oxides or nitrides of silicon, boron, aluminum, zirconium, hafnium or tellurium or Indium tin oxide (ITO). Likewise suitable are doped layers of the abovementioned variants with further elements.

A particularly suitable method for applying an inorganic barrier layer is high-power impulse magnetron sputtering and atomic layer deposition, by means of which particularly permeation-proof layers can be realized with low thermal stress on the carrier layer. Preference is given to a permeation barrier of the carrier layer with barrier function or of the composite of carrier layer and barrier layer against water vapor (WVTR) of <1 g / (m ² * d) and / or oxygen (OTR) of <1 cm ³ / (m ² * d * bar), wherein the value is in each case based on the thickness of the barrier film used, that is not normalized to a specific thickness. The WVTR is at 38 ° C and 90% relative humidity according to ASTM F-1249: 2013 and the OTR at 23 ° C and 50% relative humidity after DIN 53380 part 3: 1998-07 measured.

• Mitsubishi Chemical - X-Barrier Techbarrier
• Konica Minolta - Flexent
• Toppan Printing - GX-P-F, GL FILM, PRIME BARRIER
• 3M - MVB-1000 , FTB3
• Toray Plastics - Barrialox
• Mitsui Chemicals Tohcello, Inc - MAXBARRIER
• Vitex Systems, Inc - Barix Multilayers

Examples of barrier films with an inorganic barrier layer are:

• Mitsubishi Chemical - X-Barrier Tech Barrier
• Konica Minolta - Flexent
• Toppan Printing - GX-PF, GL FILM, PRIME BARRIER
• 3M - MVB-1000, FTB3
• Toray Plastics - Barrialox
• Mitsui Chemicals Tohcello, Inc - MAXBARRIER
• Vitex Systems, Inc - Barix Multilayers

In the method according to the invention, the use according to the invention and the composite according to the invention, in a particularly preferred embodiment, if the barrier layer is an outer layer of the barrier film, the indicator adhesive tape is arranged directly on the barrier layer of the barrier film or, if the barrier layer does not comprise an outer layer of the barrier film Barrier film is disposed on the surface of the barrier film nearest the barrier layer.

Preferred embodiments of the method according to the invention, the use according to the invention and the composite according to the invention can be found in the claims. The preferred embodiments recited in the claims or in the description of the process according to the invention, the use according to the invention or the composite according to the invention each represent preferred embodiments with regard to both the process, the use and the composite.

• ◯ 1: Trägerfolie des Indikatortapes
• ◯ 2: Reversibel eingestellte Haftklebmasseschicht
• ◯ 3: Indikatorschicht
• ◯ 4: Barriereschicht der Barrierefolie
• ◯ 5: Trägerschicht der Barrierefolie
• ◯ 6: Reversibel eingestellte Haftklebmasseschicht mit Gettermaterial
• ◯ 7: Funktionsschicht auf der Barrierefolie, z.B. Lack- oder Schutzschicht

Further details, features and advantages of the present invention are explained below with reference to preferred embodiments, which are illustrated in the accompanying figures. Where:

• ◯ 1: Carrier film of the indicator tape
• ◯ 2: Reversible pressure-sensitive adhesive layer
• ◯ 3: indicator layer
• ◯ 4: barrier layer of the barrier film
• ◯ 5: Carrier layer of the barrier film
• ◯ 6: Reversible pressure-sensitive adhesive layer with getter material
• ◯ 7: Functional layer on the barrier film, eg paint or protective layer

• 1 eine mögliche Ausführungsform eines erfindungsgemäßen Indikatortapes;
• 2 ein Laminat aus dem Indikatortape der 1 und einer Barrierefolie;
• 3 eine andere Ausführungsform eines erfindungsgemäßen Indikatortapes;
• 4 ein Laminat aus dem Indikatortape der 3 und einer Barrierefolie; und
• 5 ein Laminat aus dem Indikatortape der 3 und einer alternativen Barrierefolie.

It shows

• 1 a possible embodiment of an indicator tapes according to the invention;
• 2 a laminate from the indicator tape of 1 and a barrier film;
• 3 another embodiment of an indicator tape according to the invention;
• 4 a laminate from the indicator tape of 3 and a barrier film; and
• 5 a laminate from the indicator tape of 3 and an alternative barrier film.

1 shows a possible structure of the indicator tape, consisting of a carrier film 1 , an indicator layer applied thereto 3 and a reversibly adjusted pressure-sensitive adhesive layer 2 ,

2 shows the structure of a laminate of indicator tape consisting of carrier film 1 , Indicator layer 3 and reversibly adjusted pressure-sensitive adhesive layer 2 (ie the indicator tape off 1 ), with a barrier film consisting of a barrier layer 4 and a carrier layer 5 where the barrier layer 4 the barrier film with the reversibly adjusted PSA layer 2 the tap is in contact.

3 shows an alternative possible construction of the indicator tapes, consisting of a carrier film 1 and a reversibly adjusted pressure-sensitive adhesive layer 6 containing getter material.

4 shows the structure of a laminate of indicator tape, consisting of a carrier film 1 and a reversibly adjusted pressure-sensitive adhesive layer 6 containing getter material (ie, the indicator tape 3 ), with a barrier film consisting of a barrier layer 4 and a carrier layer 5 where the barrier layer 4 the barrier film with the reversibly adjusted PSA layer 6 the tap is in contact.

5 shows the structure of a laminate of indicator tape, consisting of a carrier film 1 and a reversibly adjusted pressure-sensitive adhesive layer 6 containing getter material (ie, the indicator tape 3 ), with a barrier film consisting of a functional layer in this order 7 (eg paint or protective layer), a barrier layer 4 and a carrier layer 5 , wherein the pressure-sensitive adhesive layer 6 of the tape is applied to the side of the barrier film, that of the barrier layer 4 is closest to the film, ie in the present case on the functional layer 7 the barrier film. In such a construction, it is to be expected that the functional layer also contains permeate, which already consumes part of the getter material in the indicator adhesive tape, before further permeate can permeate through imperfections in the barrier layer to the indicator adhesive tape. Such premature consumption, however, occurs over the entire surface and does not create any contrast in the optical properties on the surface of the indicator adhesive tape. Subsequent permeate, which partially permeates through defects in the indicator adhesive tape, however, degrades the getter material in some areas, so that the desired indication effect is also possible in this case. Therefore, premature consumption in this case preferably does not include the entire getter material in the indicator tape.

measurement methods

adhesive power

A 2 cm wide tape strip is coated with the free PSA side onto a glass substrate, i. the air side of float glass, glued by five double rolling over with a 4 kg roll. The glass substrate was previously cleaned with a cellulose cloth soaked in acetone. The substrate is clamped and the strip of adhesive tape is pulled off from the substrate via its free end on a tensile testing machine at a speed of 300 mm / min and at a peeling angle of 180 °. The measurement results are given in N / cm and are averaged out of three measurements. It is measured at 23 ° C / 50% relative humidity.

Water absorption capacity

The water absorption capacity of the getter material-containing tape is determined gravimetrically and expressed in% of its own weight. The samples are stored for at least 48 hours at 23 ° C / 50% relative humidity.

Water vapor permeation rate (WVTR)

The water vapor permeation rate (WVTR) is a measure of the transmission of water vapor through materials and is measured according to ASTM F-1249: 2013 at 38 ° C / 90% relative humidity on a 50 cm ² test area, unless otherwise specified. To determine the WVTR value determines the amount of water (in grams) that diffuses through a square meter of sample in 24 hours. The value given is the mean of two measurements and is related to the thickness of the measured specimen unless otherwise specified.

Examples

Adhesive adhesive K1:

80 parts by weight Kraton G 1657 Linear triblock copolymer of styrene and ethylene / butylene units (SEBS) having a block polystyrene content of 13% from Kraton Polymers Group of Companies 20 parts by weight TER PIB 950 Polyisobutylene with an M _w of 950 g / mol from TER HELL.

Toluene was used as the solvent. A 25% strength by weight solution of Kraton G 1657 and TER PIB 950 in toluene was prepared (pressure-sensitive adhesive K1).

If the adhesive solution K1 is applied to a conventional Silatur S75 M371 PET liner from Siliconatura by means of a laboratory coater, and the solution is dried at 120 ° C. for 10 minutes in a laboratory drying cabinet, a pressure-sensitive adhesive layer is obtained which has a thickness of 25 μm has a WVTR of 60 g / m ² d.

The following getter materials were used: designation description trade name supplier G1 calcium oxide Magnesia 72583 magnesia G2 calcium Calcium dendritic Sigma-Aldrich

Getter material G1 (30% by weight, based on the solid constituents of the formulation to be prepared) was incorporated into the adhesive solution K1 using a high-speed dispersing disk of a laboratory stirrer. The adhesive solution was previously dried by means of approximately 1 mm zeolite balls, which were filtered out again before the coating process.

To prepare the indicator tape P1 according to the invention, the adhesive solution K1 filled with getter material G1 was applied to a conventional PET liner of the Silphan S75 M371 type from Siliconatura by means of a laboratory coater and dried. The drying took place at 120 ° C. for 10 min in a laboratory drying cabinet. The thickness of the resulting pressure-sensitive adhesive layer after drying was 25 μm. This was then Haftklebmasseschicht (<1 g / m ² d 30 microns thickness, WVTR, of the company [ON] line laminating & Technology Center GmbH & Co KG) to an aluminum foil laminated via Tischrollenlaminator. The WVTR of the resulting indicator tape P1 (without liner) was <0.1 g / m ² d, the adhesion to glass 0.06 N / cm and the water absorption capacity 2.21%.

To produce the indicator tape P2 according to the invention, the adhesive solution K1 was applied to a conventional PET liner of the Silphan S75 M371 type from Siliconatura by means of a laboratory coater and dried. The drying took place at 120 ° C. for 10 min in a laboratory drying cabinet. The thickness of the resulting pressure-sensitive adhesive layer after drying was 25 μm. This Haftklebmasseschicht was then transferred to a glove box on an aluminum foil (30 micron, WVTR <1 g / m ² d, the company [ON] line laminating & Technology Center GmbH & Co KG) laminated via Tischrollenlaminator, on the previously thick, a 100 nm layer elemental calcium had been evaporated. The pressure-sensitive adhesive layer was laminated to the evaporated calcium layer. The WVTR of the resulting indicator tape P2 (without liner) was <0.1 g / m ² d and the bond strength to glass was 0.06 N / cm. The water absorption capacity could not be determined gravimetrically due to the very thin calcium layer.

The determined bond strengths of the indicator tapes P1 and P2 on glass show that the PSA layers contained therein are reversibly adjusted PSA layers.

The tape P1 was then applied by means of a hand roller to the barrier layer of a non-pre-dried barrier film (GX-PF from Toppan Printing, 30 microns thick, WVTR 0.13 g / m ² d) and so resulting laminate stored at 85 ° C / 85% relative humidity. In a light microscopic examination (100x magnification) after 16 h point-like changes in the tape can be seen (see. 6 and 7 ). The water, which has migrated through the pinholes, reacts with the available getter material at the corresponding point in the tape and thus causes the decolorization of the gray / white adhesive. With a light microscope at 100x magnification even the smallest defects can be detected by the color difference.

The transparency of the PSA is also caused by water that can diffuse into the adhesive from the sides (see FIG. 6 ). This progressive water front can also be considered as a quality feature of the tap. As long as a color change can be seen from the sides, the getter material in the tape is still active and in principle able to display pinholes.

The position of the pinholes in the barrier film can also be detected with the naked eye by the steady growth of the discolored areas (see FIG. 8th ).

It has surprisingly been found that storage in a humid climate is not absolutely necessary in order to identify defects in the barrier film. Thus, the tape P2 was laminated to the barrier layer of a non-pre-dried barrier film (GX-PF from Toppan Printing, 30 μm thick, WVTR 0.13 g / m ² * d) by means of a table roll laminator. The laminate was then stored in a sealed aluminum bag at 60 ° C. After only one day, many punctiform defects in the getter material-containing PSA layer were visible to the naked eye (cf. 9 ).

Water which was contained in the carrier layer of the barrier film and diffused from it through the pinholes is responsible for this decolorization reaction. This allows the use of the method according to the invention even when wound on the roll barrier films in which the access of external moisture is hindered to the layers on the roll. The method is therefore preferably used for rolls of barrier film and adhesive adhesive tape wound onto the roll.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012211335 A1 [0008]
• US 6936131 B1 [0008]
• US 2010/0272933 A1 [0008]
• EP 1407818 A1 [0008]
• US 9548473 B2 [0008]
• US 2012/0164434 A1 [0009]
• DE 102012224319 A1 [0010]

Cited non-patent literature

• DIN 53380 part 3: 1998-07 [0042]

Claims (17)

Use of an adhesive tape comprising - at least one preferably reversibly adjusted PSA layer, - at least one getter material which exhibits a change in the optical properties on permeate pickup, and - optionally a carrier film which preferably has a water vapor permeation rate <1 g / m ² d, for the detection of Defects, in particular pinholes, in a barrier film, wherein the barrier film has at least one barrier layer and optionally a carrier layer. Use after Claim 1 , characterized in that the adhesive tape in addition to the at least one pressure-sensitive adhesive layer has at least one layer containing at least one getter material. Use after Claim 1 , characterized in that the pressure-sensitive adhesive layer contains the at least one getter material. Use according to one of Claims 1 to 3 , characterized in that the permeate is water and the getter material is a desiccant. Use according to one of Claims 1 to 4 , characterized in that the getter material is at least one substance selected from the group consisting of calcium oxide, calcium, iron, barium, lithium chloride and cobalt chloride. Use according to one of Claims 1 to 5 , characterized in that the barrier layer is an inorganic barrier layer, preferably selected from deposited metals, such as in particular aluminum, silver, gold and nickel, and (semi-) metal oxides, nitrides and hydronitrides, in particular oxides and nitrides of silicon, the Bors, aluminum, zirconium, hafnium and tellurium or indium tin oxide. Use according to one of Claims 1 to 6 , characterized in that the adhesive tape, if the barrier layer is an outer layer of the barrier film, is applied to the barrier layer of the barrier film or, if the barrier layer is not an outer layer of the barrier film, is applied to the surface of the barrier film closest to the barrier layer. Use according to one of Claims 1 to 7 , characterized in that the adhesive tape consists of at least one preferably reversibly adjusted pressure-sensitive adhesive layer, at least one getter material which exhibits a change in the optical properties upon permeate absorption, and optionally a carrier film which preferably has a water vapor permeation rate <1 g / m ² d. Method for detecting defects, in particular pinholes, in a barrier film, the barrier film having at least one barrier layer and optionally a carrier layer, by means of an adhesive tape comprising at least one preferably reversibly adjusted PSA layer, at least one getter material which shows a change in the optical properties on permeate pickup , and optionally a carrier film, which preferably has a water vapor permeation rate <1 g / m ² d, characterized in that the method comprises the following steps: - producing a substantially full-surface composite of the adhesive tape and the barrier film; - Storage of the composite, preferably in humid and warm climates; - Detecting the optical change of the getter material; optionally marking the defects in the barrier film indicated by the optical change of the getter material; and peeling off the adhesive tape from the barrier film. Method according to Claim 9 , characterized in that in the composite of the adhesive tape and the barrier film, the adhesive tape, if the barrier layer is an outer layer of the barrier film, is disposed on the barrier layer of the barrier film or, if the barrier layer is not an outer layer of the barrier film, on the surface closest to the barrier layer the barrier film is arranged. Method according to Claim 9 or 10 , characterized in that the composite of the adhesive tape and the barrier film is produced by lamination of the adhesive tape to the barrier film. Method according to one of Claims 9 to 11 , characterized in that the adhesive tape consists of at least one preferably reversibly adjusted pressure-sensitive adhesive layer, at least one getter material which exhibits a change in the optical properties upon permeate absorption, and optionally a carrier film which preferably has a water vapor permeation rate <1 g / m ² d. Composite of a barrier film, wherein the barrier film has at least one barrier layer and optionally a carrier layer, and an adhesive tape comprising at least one preferably reversibly adjusted pressure-sensitive adhesive layer, at least one getter material showing a change in the optical properties on permeate absorption, and optionally a carrier film, which preferably has a Wasserdampfpermeationsrate <1 g / m ² d, wherein the composite is substantially full-surface. Composite after Claim 13 , characterized in that the adhesive tape, if the barrier layer is an outer layer of the barrier film, is arranged on the barrier layer of the barrier film or, if the barrier layer is not an outer layer of the barrier film, is arranged on the surface of the barrier film closest to the barrier layer. Composite after Claim 13 or 14 , characterized in that the adhesive tape in addition to the at least one pressure-sensitive adhesive layer has at least one layer containing at least one getter material. Composite after Claim 13 or 14 , characterized in that the pressure-sensitive adhesive layer contains the at least one getter material. Verbund according to one of the Claims 13 to 16 , characterized in that it is wound up as a roll.

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