Method for removing permeates from sheet material

Abstract

The invention relates to a method for absorbing permeates from a sheet material I, as used, for example, in organic electronic structures, this method being easy to carry out. Such a method includes, according to the invention, directly or indirectly bringing sheet material I into planar contact with a sheet material II, which contains at least one getter material and is capable of absorbing at least one permeate from sheet material I, there being no adhesive connection between sheet material I and sheet material II.

Claims

1. A method for removing permeates from a flat structure I that is at least partially used in a structure of an organic electronic device, comprising: a) directly or indirectly bringing the flat structure I into planar contact with a flat structure II, said flat structure II containing at least one getter material and is capable of taking up at least one permeate from the flat structure I, wherein: no adhesive bonding takes place between the flat structures I and II, the planar contact between the flat structures I and II has a bonding strength of less than 0.5 N/cm, and the flat structure II does not remain in the organic electronic device.

2. The method of claim 1, wherein step a) takes place in such a way that the flat structure I and the flat structure II form a composite, and the composite is configured in alternating layers.

3. The method of claim 1, wherein the at least one getter material is selected from the group consisting of cobalt chloride, calcium chloride, calcium bromide, lithium chloride, lithium bromide, magnesium chloride, barium perchlorate, magnesium perchlorate, zinc chloride, zinc bromide, aluminium sulfate, calcium sulfate, copper sulfate, barium sulfate, magnesium sulfate, lithium sulfate, sodium sulfate, cobalt sulfate, titanium sulfate, sodium carbonate, sodium sulfate, potassium carbonate, magnesium carbonate, diatomaceous earth, silicic acids, and zeolites, and layered silicates, iron, calcium, barium, sodium, magnesium, barium oxide, calcium oxide, iron oxide, magnesium oxide, sodium oxide, titanium dioxide, potassium oxide, strontium oxide, activated aluminum oxide, carbon nanotubes, activated carbon, phosphorus pentoxide, silanes, calcium hydride, barium hydride, strontium hydride, sodium hydride, lithium aluminium hydride, potassium hydroxide, sodium hydroxide, aluminium acetyl acetonate and acetic anhydride, propionic anhydride, butyric anhydride, methyltetrahydrophthalic anhydride, polyacrylic acid, and polyvinyl alcohol.

4. The method of claim 1, wherein the at least one getter material is selected from the group consisting of barium, calcium, calcium sulfate, calcium chloride, calcium oxide, sodium sulfate, potassium carbonate, copper sulfate, magnesium perchlorate, magnesium sulfate, lithium chloride, silicic acids, zeolites, and mixtures of two or more of the above substances.

5. The method of claim 1, wherein the flat structure II comprises one or more getter-material containing layers, and each getter-material-containing layer of the flat structure II contains at least 10 wt. % of getter material, relative in each case to total weight of each respective getter-material containing layer.

6. The method as claimed in claim 1, wherein the flat structure II has a permeate content of less than 1000 ppm before application.

7. The method of claim 1, wherein the flat structure II comprises one or more layers and at least one layer of the flat structure II, which is arranged on a side of a getter-material-containing layer facing away from the flat structure I after step a), has a water vapor transmission rate (WVTR) of less than 50 g/(m.sup.2*d).

8. The method of claim 1, wherein a matrix material of a getter-material-containing layer of the flat structure II and/or a material for an outer layer of the flat structure II provided for contact with the flat structure I is an elastomer.

9. The method of claim 1, comprising a further step b) of removing the flat structure I from the flat structure II prior to use of flat structure I in the structure of an organic electronic device.

10. The method of claim 1, wherein the flat structure I has a constant thickness over its entire surface area.

11. The method of claim 1, wherein the flat structure II consists of a layer of getter material.

Description

(1) Possible embodiments of a flat structure containing getter material according to the invention are shown in FIGS. 1 through 4. The figures denote the following.

(2) FIG. 1: An embodiment of a flat structure containing getter material according to the invention disclosed herein. 10: Non-adhesive elastomeric contact layer 20: Layer containing getter material 30: Substrate material with WVTR<1 g/m.sup.2 d at 38 C. and 90% rH in relation to the thickness of the substrate material used

(3) FIG. 2: An embodiment of a flat structure containing getter material according to the invention disclosed herein. 10: Non-adhesive elastomeric contact layer 20: Layer containing getter material 11. Optionally: further non-adhesive contact layer

(4) FIG. 3: An embodiment of a flat structure containing getter material according to the invention disclosed herein 10: Non-adhesive elastomeric contact layer 20: Layer containing getter material 31: Substrate material 11: Optionally: further non-adhesive elastomeric contact layer

(5) FIG. 4: An embodiment of a flat structure containing getter material according to the invention disclosed herein. 32: Substrate material 20: Layer containing getter material 31: Substrate material

(6) A further object of the invention is the use of a flat structure according to the invention for removing permeates from a flat structure, preferably for at least partial removal of at least water from a flat structure.

EXAMPLE SECTION

(7) Various flat structures containing getter material were manufactured to carry out the method.

(8) Non-Adhesive Elastomer Layers and Adhesives:

(9) In order to produce layers, various materials from a solution were applied to a conventional liner, the Silphan S75 M371 manufactured by Siliconature, by means of a laboratory application device and then dried. The layer thickness after drying was 50 m. Drying was carried out in all cases at 120 C. for 30 min in a laboratory drying cabinet.

(10) M1: Pressure-Sensitive Adhesive Compound

(11) TABLE-US-00001 100 parts Tuftec P 1500 SBBS with 30 wt. % block polystyrene content from Asahi. The SBBS as a diblock content of approx. 68 wt. %. 100 parts Escorez 5600 Hydrated KW resin with a softening point of 100 C. from Exxon 25 parts Ondina 917 White oil from paraffin and naphthenic components from Shell

(12) A mixture of toluene and acetone in a 2:1 ratio was used as a solvent.

(13) M2: Non-Adhesive Elastomer

(14) TABLE-US-00002 100 parts Tuftec P 1500 SBBS containing 30 wt. % block polystyrene from Asahi. The SBBS has a diblock content of 68 wt. %.

(15) A mixture of toluene and acetone in a 2:1 ratio was used as a solvent.

(16) M3: Non-Adhesive Elastomer

(17) TABLE-US-00003 100 parts Oppanol B 150 PIB from BASF, Mw = 425,000 g/mol

(18) SBP spirit was used as a solvent.

(19) Water vapor transmission rate (WVTR) was measured at 38 C. and 90% relative humidity according to ASTM F-1249. The indicated value is the mean value of two measurements.

(20) Adhesion to steel was determined analogously to ISO 29862 (Method 3) at 23 C. and 50% relative humidity at a detachment rate of 300 mm/min and detachment angle of 180. An etched PET film with a thickness of 50 m was used as a reinforcing film, of the type available from Coveme (Italy). Bonding of the measurement strip was conducted using a roller applicator at a temperature of 23 C. The adhesive tapes were immediately pulled off after application. The indicated value is the mean value of three measurements.

(21) TABLE-US-00004 Designation WVTR [g/m.sup.2 d] Adhesion/steel [N/cm] M1 68 7.1 M2 85 <0.1 (measurement limit) M3 6 <0.1

(22) The values determined for adhesion to steel show that compounds M2-M3 are non-adhesive materials.

(23) The following getter materials were used:

(24) TABLE-US-00005 Designation Description Commercial name Supplier G1 Calcium oxide Calcium oxide Sigma-Aldrich nanopowder G2 Zeolite 3A Purmol 3 STH Zeochem

(25) The getter materials were incorporated into the compound solutions using a high-speed dispersion disk of a laboratory agitator. The compound solutions were first dried using zeolite beads measuring approx. 1 mm, which were again filtered out before the coating process. The getter-material-containing layers were produced with a thickness of 100 m.

(26) An approx. 12 m-thick polyester film coated with an inorganic barrier layer (GX-P-F made by Toppan Printing) was used as substrate material B1. The film has a water vapor transmission rate of 0.06 g/m.sup.2 d. The getter-material-containing layers were coated on the side with the inorganic barrier layer of the film from the solution and dried.

(27) As substrate material B2, a BOPP film having a thickness of 36 m manufactured by Pao-Yan, Taiwan, was used, said film having a WVTR of 68 g/m.sup.2 d.

(28) Table 1 shows an overview of the getter-material-containing flat structures produced as an individual layer or as a structure according to specified figures.

(29) TABLE-US-00006 TABLE 1 Getter material-filled flat structures: Structure Content of according Non-adhesive Matrix getter to FIG. Substrate Designation elastomer material Matrix [wt. %] no. film T1 M2 G2 10 Single layer T2 M2 G2 20 Single layer T3 M2 G2 40 Single layer T4 M3 G1 10 Single layer T5 M3 G1 20 Single layer T6 M3 G1 40 Single layer T7 M3 M1 G2 20 1 B1 T8 M3 M1 G2 40 1 B1 T9 M3 M1 G2 20 3 B2 T10 M3 M1 G2 40 3 B2 T11 M1 G2 20 4 B2 T12 M1 G2 40 4 B2 V1 M1 G2 20 B2 V2 Single layer

(30) As comparative example V1, an adhesive getter-material-containing flat structure was produced from the getter-filled adhesive M1, which was laminated onto the substrate material B2.

(31) As a further comparative example V2, a conventional printer paper with a mass per unit area of 80 g/m.sup.2 was used. This was first conditioned for 24 h at 23 C. and 50% rH and then predried for 1 h at 120 C. in a drying cabinet.

(32) When an adhesive matrix material (MI) was used, a 50 m thick layer of a non-adhesive elastomer or the corresponding substrate film was laminated onto said material by means of a laboratory roll laminator, with care being taken to expose the getter-material-containing layer to the surrounding atmosphere for as short a period as possible after drying.

(33) T13: Getter-Material-Containing Multilayer Polyolefin Film

(34) Furthermore, a polyolefin(PO)-based film was produced by flat film coextrusion. It was composed of a 50 m-thick base layer and two 10 m-thick outer layers. The base layer was composed of 79.7 wt. % of the polypropylene block copolymer Novolen 2309 L (BASF, melt flow index 6 g/10 min at 230 C. and 2.16 kg, ethylene content of approx. 6.5 wt. %), 20 wt. % of the getter material G2, and 0.3% (w/w) of the HALS stabilizer Tinuvin 770. The base layer material was compounded in-line by flat-film extrusion on a twin-screw extruder from Coperion (d=25 mm, L/d=37) and fed by means of an interconnected melt pump into the feed block of the coextruder. The getter material was supplied to the twin-screw extruder via a side feeder after fusion and homogenizing of the polymer components.

(35) The outer layer was composed of 85 wt. % of the ethylene multiblock copolymer Infuse D9107 (The Dow Chemical Company, d=0.866 g/cm.sup.3) and 15 wt. % of the polyethylene LD251 (ExxonMobil, d=0.9155). The outer layer material was extruded on two extruders manufactured by Dr. Collin and fed into the feed block of the coextruder.

(36) A polyester film approx. 50 m in thickness coated with an inorganic barrier layer (Celle) T0500, Kureha, Japan) was used as a flat structure from which permeate was to be removed, said type of film also being used for encapsulation in organic electronic structures. The film was conditioned for 24 h at 23 C. and 50% rH before use.

(37) A 50 m-thick layer of a pressure-sensitive adhesive for the encapsulation of organic electronic structures such as that described in DE 102008047964A1, example 3 was used as a further flat structure from which permeate was to be removed. In this case, the adhesive was covered on both sides with a conventional liner of the SILPHAN S36 M372 type (36 m PET). The flat structure was conditioned for 24 h at 23 C. and 50% rH before use.

(38) Sections of the flat structure containing getter material measuring approx. 1010 cm.sup.2 were placed at 23 C. and 50% rH on the non-inorganically coated side of a section of the polyester film of the same size or on the liner of the pressure-sensitive adhesive and thus brought into contact with the flat structure to be dried.

(39) With flat structures T2, T5, T7, and T9, an additional test was conducted in which the flat structures were first stored open for 8 hours at 23 C. and 50% rH and only then placed on the polyester film.

(40) The composites produced in this manner were stored for 14 days at 23 C. in an impermeable package (sealed in an aluminum composite film), with the sample bags being weighed down over the entire surface of the inwardly-positioned sample with a weight of approx. 100 g in order to maintain the contact. The samples were then removed from their package in a glove box (atmosphere: water vapor <5 ppm, oxygen <1 ppm), and the respective flat structure was removed from the polyester film. A section of the polyester film was immediately sealed in a glass container for water content determination. In the case of the adhesive compound, both liners were removed, and the water content of the adhesive compound layer was determined.

(41) Water Content Measurement

(42) Water content was determined according to DIN 53715 (Karl Fischer titration). Measurement was conducted on a Karl-Fischer Coulometer 851 in combination with an oven sampler (oven temperature 140 C.). Triple determination was carried out with an initial weight of approx. 0.3 g. The arithmetic mean of the measurements is given as the water content.

(43) Table 2 shows the results:

(44) TABLE-US-00007 TABLE 2 Results of the drying process Designation of flat structure containing Water content of flat getter material, applied Flat structure to be structure to be dried and then removed dried [ppm] PET film 3290 (conditioned film) T1 194 T2 18 T3 9 T4 73 T5 10 T6 8 T7 24 T8 17 T9 20 T10 6 T11 15 T12 10 T13 9 T2 - conditioned 8 h 836 T5 - conditioned 8 h 90 T7 - conditioned 8 h 18 T9 - conditioned 8 h 461 V1 16 V2 - conditioned 24 h 2810 V2 - dried 1 h 460 Pressure-sensitive 914 (conditioned adhesive pressure-sensitive adhesive) T2 32 T3 13 T6 24 T8 14 T10 26 T12 33

(45) The results show that outstanding drying results can be achieved that are impossible using the methods of the prior art (V2). Even with pre-dried paper, a water content of less than 200 ppm, in particular less than 50 ppm, cannot be achieved, and this water content is required for materials used in an organic electronic structure.

(46) The water content of the flat structures T1-T6 filled with getter material was also determined prior to application: it was less than 10 ppm in each case. It was below 1000 ppm for flat structures T7-T8 and below 500 ppm for T9-T12. In contrast, the dried paper V2 showed a water content of approx. 9200 ppm. This shows that a permeate content of less than 1000 ppm is advantageous for achieving an extremely low permeate content.

(47) Surprisingly, the tests conducted with the method according to the invention do not generally show inferior release of permeate compared to the comparative example using an adhesive compound containing getter material (V1), although the person having ordinary skill in the art would have expected that simple application of the flat-structure-containing getter material, because of its absent or barely noticeable flowability, would establish less contact with the adhesive substrate, and that the material transport would therefore be reduced. However, because of its adhesive properties, removal of the pressure-sensitive adhesive getter-material-containing flat structure from the PET test substrate was significantly more difficult compared to the non-adhesive flat structures.

(48) Both of the getter materials used are found to be suitable. Surprisingly, tests using a small amount of getter material in the adhesive tape (T1, T4) show only a slight decrease in efficacy compared to those conducted with a higher degree of filling (T2, T3 or T5, T6).

(49) Surprisingly, flat structures with the composition according to FIG. 1 (T7, T8), FIG. 3 (T9, T10), or FIG. 4 (T11, T12), in which material transport must first take place through a low-permeability layer and the permeate must first be removed from this layer and the substrate film, also showed no noteworthy impairment of properties.

(50) Compared to the method with the flat structures T2 and T5, which are laminated after one-hour conditioning onto the test barrier substrate, the advantage of an adhesive compound with a low permeation rate can be seen: after conditioning, T2 shows a significant decrease in drying performance, while the adhesive tape T5 with the significantly less permeable adhesive shows virtually no decrease in drying performance.

(51) The results are similar with the considerably less permeable substrate material B1. With the latter, less of a decrease in drying performance after conditioning is observed than the more permeable substrate material B2 (T7 vs. T9).

(52) In a further test, a composite of the getter-material-containing flat structure T10 was wound together with the PET test substrate into a roll having a running length of approx. 20 m, producing a stack of approx. 70 layers on the roller core. Layering was carried out as described above.

(53) In order to measure water content, samples were taken from linear meter 2 (near the core), 10 (middle of the roll), and 19 (outer side of the roll). It was found that water content at all three sites was within the range of 8-13 ppm, showing outstanding homogeneity of drying throughout the roll. The method according to the invention is also outstandingly well-suited for the drying of stacked flat structures.