Adhesive tape for encapsulating electronic constructions
The aim is to provide an adhesive tape that effectively protects an electronic construction from permeants, especially water, and that at the same time has good gap-filling qualities. To solve this problem an adhesive tape is proposed that has in the following order:—a carrier layer without barrier effect at least towards water and with a WVTR of at least 1 g/(m 2 *d) (38° C., 90% relative humidity, 50 μm layer thickness); —a layer comprising at least one getter material capable of sorbing at least water; —a water barrier ply; and—a layer of pressure-sensitive adhesive, where the carrier layer bears an outward-facing release layer and/or the layer of pressure-sensitive adhesive is lined with a release liner which has a release layer lying on the layer of pressure-sensitive adhesive.
1. An adhesive tape for encapsulating electronic structures, comprising in the following order:
a carrier layer without a barrier effect at least against water having a WVTR of at least 1 g/(m 2 *d) (38° C., 90% relative humidity, 50 μm layer thickness);
a layer containing at least one getter material capable of sorption at least of water;
a layer having a barrier effect against water;
a pressure-sensitive adhesive layer;
wherein an outward-facing release layer lies on the carrier layer and/or the pressure-sensitive adhesive layer is covered with a release liner that has a release layer lying on the pressure-sensitive adhesive layer.
2. The adhesive tape as claimed in claim 1 , wherein the carrier layer without a barrier effect at least against water
is a film comprising a material selected from the group consisting of ethylene vinyl acetate, polyurethanes, cellulose acetate, polymethyl methacrylate, polyvinyl alcohols and paper or is a microperforated polyethylene film.
3. The adhesive tape as claimed in claim 1 , wherein the getter material is selected from the group consisting of absorbent and adsorbent materials.
4. The adhesive tape as claimed in claim 1 , wherein the getter material is selected from the group composed of calcium chloride, calcium oxide, boron trioxide, sodium sulfate, potassium carbonate, copper sulfate, magnesium perchlorate, magnesium sulfate, zeolites and mixtures of two or more of the above-mentioned substances.
5. The adhesive tape as claimed in claim 1 , wherein the getter material is in the form of a dispersed phase.
6. The adhesive tape as claimed in claim 5 , wherein the getter material is in the form of a dispersed phase in an adhesive.
7. The adhesive tape as claimed in claim 1 , wherein the pressure-sensitive adhesive layer comprises a polymer base selected from the group consisting of styrene block copolymers, polyolefins and epoxy resins, and mixtures of two or more of these polymers.
8. The adhesive tape as claimed in claim 1 , wherein the pressure-sensitive adhesive layer is covered with the release liner that has a release layer lying on the pressure-sensitive adhesive layer, wherein this release layer is a silicone, fluorinated silicone, silicone-copolymer, fluoropolymer, polycarbamate or polyolefin release layer.
9. The adhesive tape as claimed in claim 1 , wherein the outward-facing release layer lies on the carrier layer and this release layer is a silicone release coating.
10. The adhesive tape as claimed in claim 1 , wherein the layer having a barrier effect against water is selected from the group consisting of: (A) a composite of (i) a film selected from the group consisting of polyurethane, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride, polyethylene-2,6-naphthalate, polyacrylonitrile, polyethylene terephthalate, ethylene-vinyl alcohol copolymer, polyacrylate, and poly-ε-caprolactam films and (ii) at least one permeation-inhibiting layer arranged between said film (i) and the pressure-sensitive adhesive layer; (B) a metallic film; and (C) a glass film.
11. A method comprising encapsulating an electronic structure with the adhesive tape as claimed in claim 1 .