Packing material for corrosible metallic objects
The invention relates to a packaging material for corrosible metallic objects, comprised of a plastic film forming a package outer surface, an inner layer, and an adhesive layer bonding the plastic film to the inner layer, wherein the adhesive layer comprises a volatile corrosion inhibitor and the inner layer has a high permeability for the corrosion inhibitor on the package outer surface as compared to the plastic film. According to the invention the adhesive layer is formed by a chemically binding reaction adhesive.
1. A packaging material for corrosible metallic objects, comprised of a plastic film forming a package outer surface, an inner textile layer, and a hardened foamed adhesive layer bonding the plastic film to the inner textile layer, wherein the hardened foamed adhesive layer is a chemically set reaction adhesive which comprises a polyurethane, water, a volatile corrosion inhibitor and on a surface of the hardened foamed adhesive layer, a plurality of small gas bubbles consisting of carbon dioxide in the micrometer to nanometer range which are created by a chemical reaction with gas formation during the hardening of the foamed adhesive, and the inner textile layer contains fibers which partially penetrate through a surface of the hardened foam adhesive layer and which has a higher permeability for the corrosion inhibitor on the package outer surface as compared to the permeability for the corrosion inhibitor for the plastic film.
2. The packaging material according to claim 1 wherein the structure of the hardened foamed adhesive is a foamed plastic material.
3. The packaging material according to claim 2 wherein the foamed adhesive layer as a result of the gas formation has a layer thickness that is two to five times the thickness of the unfoamed adhesive applied.
4. The packaging material according to claim 3 wherein a monocomponent reaction resin adhesive is used as the reaction adhesive that polymerizes when exposed to air moisture.
5. The packaging material according to claim 1 wherein the reaction adhesive is a solvent-free polyurethane adhesive basically comprised of aliphatic or aromatic isocyanates.
6. The packaging material according to claim 1 wherein the reaction adhesive is a two-component reaction resin adhesive.
7. The packaging material according to claim 1 wherein the foamed adhesive layer features an application weight of 1 g/m 2 to 10 g/m 2 .
8. The packaging material according to claim 1 wherein the corrosion inhibitor is present in the foamed adhesive layer at an amount of 0.1 g/m 2 to 5 g/m 2 , based on the surface of the packaging material.
9. The packaging material according to claim 8 wherein the corrosion inhibitor is evenly distributed within the foamed adhesive layer.
10. The packaging material according to claim 1 wherein the plastic film and the inner textile layer are bonded to each other in surface contact by the uniformly distributed foamed adhesive layer.
11. The packaging material according to claim 1 wherein the foamed adhesive layer forms a pattern of adhesive surfaces or adhesive-free surfaces.
12. The packaging material according to claim 1 wherein the plastic film is comprised of a polymer forming a barrier against the migration of the corrosion inhibitor.
13. The packaging material according to claim 1 wherein the plastic film is comprised of a polyolefin or a polyolefin copolymer.
14. The packaging material according to claim 1 wherein the plastic film has multiple layers and has a blocking layer featuring a higher diffusion resistance for the corrosion inhibitor than the inner layer.
15. The packaging material according to claim 1 wherein the plastic film has a thickness of between 10 and 120 μm.
16. The packaging material according to claim 1 wherein a face of the plastic film turned toward the foamed adhesive layer has a modified surface structure for improving the adhesive bond.
17. The packaging material according to claim 1 wherein the inner textile layer is comprised of a nonwoven material from polymer fibers.
18. The packaging material according to claim 17 wherein the nonwoven material is a spunbond nonwoven material, a meltblown nonwoven material, or a combination of spunbond and meltblown nonwoven materials.
19. The packaging material according to claim 1 wherein the inner textile layer is comprised of a fabric, interlaced fabric, or knitted fabric.
20. The packaging material according to claim 1 wherein the total thickness is between 70 μm and 200 μm.
21. The packaging material according to claim 16 wherein a face of the plastic film turned toward the foamed adhesive layer has a Corona pretreatment modified surface structure.
22. The packaging material according to claim 14 wherein the blocking layer is formed by a metal coating.