A PROCESS FOR PREPARATION OF A COMPOSITE LAYER OR A LAMINATE, AND PRODUCT OBTAINED THEREWITH

Abstract

The invention relates to a process for preparing a composite layer, by applying an oligomeric organic compound layer on a substrate with a metal or metal oxide layer by vapour deposition, comprising the steps of (a) providing a substrate layer, (b) applying a metal or metal oxide layer under reduced pressure on said substrate, and (c) vapour depositing the oligomeric organic compound on the metal or metal oxide layer while the film remains at reduced pressure, wherein the oligomeric compound is evaporated from an oligomeric or polymeric compound comprising a stabiliser, or wherein the oligomeric compound is amorphous, or has a high solubility in certain solvents.

Claims

1. Process for preparing a composite layer, by applying an oligomeric organic compound layer on a substrate with a metal or metal oxide layer by vapour deposition, comprising the steps of a) providing a substrate layer, b) applying a metal or metal oxide layer under reduced pressure on said substrate, and c) vapour depositing the oligomeric organic compound on the metal or metal oxide layer while the film remains at reduced pressure, wherein the oligomeric compound is evaporated from an oligomeric or polymeric compound comprising a stabiliser.

2. Process for preparing a composite layer, by applying an organic compound layer on a substrate with a metal or metal oxide layer by vapour deposition, comprising the steps of a) providing a substrate layer, b) applying a metal or metal oxide layer under reduced pressure on said substrate, and c) vapour depositing the organic compound on the metal or metal oxide layer while the film remains at reduced pressure, wherein the oligomeric compound is evaporated from an oligomeric or polymeric compound which after deposition on metal or metal oxide layer form an amorphous phase, wherein amorphous is defined by X-ray diffraction (XRD), which should not show a diffraction pattern representing ordening of molecules or polymer chains below 5 nm.

3. Process for preparing a composite layer, by applying an organic compound layer on a substrate with a metal or metal oxide layer by vapour deposition, comprising the steps of a) providing a substrate layer, b) applying a metal or metal oxide layer under reduced pressure on said substrate, and c) vapour depositing the organic compound on the metal or metal oxide layer while the film remains at reduced pressure, wherein the oligomeric compound is evaporated from an oligomeric or polymeric compound, wherein the vapour deposited organic compound has a high solubility in alcohols, such as ethanol, ethoxypropanol, methoxypropanol and n-propanol, and/or esters, such as ethyl acetate and n-propyl acetate, and/or ketones such as methyl ethyl ketone, and/or toluene and/or water.

4. The process according to any one of the preceding claims, wherein the process is performed in a roll-to-roll process at a speed of at least 1 m/s, preferably at least 6 m/s, and more preferably at least 8 m/s, and wherein the speed is less than 60 m/sec.

5. The process according to anyone of the preceding claims, wherein the process is performed with rolls of about 1 m wide or more, preferably, about 1.25 m wide or more, and preferably about 5 m wide or less, wherein the length of the roles used in the process of the invention is about 5000 m or more, preferably about 10000 m or more, and more preferably about 20000 m or more

6. The process according to anyone of the preceding claims, wherein the process is performed in the production of composite layers and laminate films for food and medical packaging.

7. The process according to anyone of the preceding claims, wherein the process is performed with an oligomeric organic compound which is sufficient polar to adhere well to the substrate.

8. The process according to anyone of the preceding claims, wherein the molecular weight of the oligomeric organic compound as present on the metal or metal-oxide layer is higher than 500, preferably higher than 1000, wherein the oligomeric organic compound is not polymerized on the surface.

9. The process according to anyone of the preceding claims, wherein about 50 wt % of the oligomeric organic compound layer will have a molecular weight lower than about 30,000.

10. The process according to anyone of the preceding claims, wherein the oligomeric organic compound layer is made from oligomers or polymers, which are cleaved when heated at sufficiently high temperature creating adequate vapor pressure for roll-roll coating process.

11. The process according to anyone of the preceding claims, wherein the oligomers or polymers evaporated in the heating chamber is chosen from the group consisting of polyvinylacetate, polyvinylalcohol (PVOH), thermoplastic polyester (like PET or PBT), polylactides, polyglycolides, polylactones, polyhydroxybutyrate-valerate polymers, polyamides (nylons), polycarbonates, ethylene-acrylic polymers, ethylene vinyl alcohol, chlorinated polyethylenes, polyurethanes, styrene-maleic acid anhydride copolymers, vinylidene chloride polymers and the like.

12. The process according to anyone of claims 1-10, wherein the oligomers or polymers evaporated in the heating chamber is chosen from the group consisting of polyolefins like polyethylene or polypropylene, and polystyrene, and wherein polar groups are introduced during the evaporation step with a plasma treatment using oxygen as plasma gas, in the space between the evaporator and the deposition surface.

13. The process according to anyone of the preceding claims, wherein the oligomeric organic compound layer is made from oligomers or polymers, wherein the oligomer or polymers used as material in the evaporator comprises an antioxidant, such as phenolic anti-oxidants, organic phosphorus compounds and lactone (benzofuranone) stabilizers.

14. Process for preparing a composite layer, by applying an siloxane based material on a substrate with a metal or metal oxide layer by vapour deposition, comprising the steps of a) providing a substrate layer, b) applying a metal or metal oxide layer under reduced pressure on said substrate, and c) vapour depositing the siloxane based material with plasma polymerisation to obtain a polymerised siloxane coating.

15. Process for preparing a composite layer, by applying an allyl or acrylate based material on a substrate with a metal or metal oxide layer by vapour deposition, comprising the steps of a) providing a substrate layer, b) applying a metal or metal oxide layer under reduced pressure on said substrate, and c) vapour depositing the allyl or acrylate based material while applying plasma polymerisation to obtain a polymerised coating.

16. Process according to any one of claim 14 or 15, in combination with of any one of claims 4, 5 and 6.

17. Composite layer obtained with a process according to any one of the preceding claims.

18. Laminate comprising a composite layer according to claim 17, and a further film, provided on the oligomeric organic compound layer, wherein preferably the laminate comprises an adhesive layer between the oligomeric organic compound layer and the further plastic film, or wherein the laminate is prepared by extrusion lamination or coating.

19. Laminate according to claim 18 or composite layer according to claim 17, wherein the laminate or composite layer comprises a printed pattern.

20. A laminate or composite layer according to any one of claims 17-19, wherein the metal or metal oxide layer is a layer from aluminium, aluminium oxide, magnesium oxide, silicium oxide or silicium nitride.

Description

[0182] The invention will be further elucidated by the following non-limiting examples.

Examples 1-3 and Comparative Experiment 1

[0183] In a roll-to-roll coating apparatus equipped with a long heatable chamber coating experiments are performed. A biaxially oriented polypropylene film (BOPP) of 20 μm thickness with a length of 20,000 m is coated with aluminum (average optical density (OD) of 2.0), and subsequently with an oligomeric organic compound as shown in the table at a vacuum of1×10.sup.−3 mbar. The film speed is 10 m/sec.

[0184] The alumina coated roll is stored for 6 month, and thereafter further processed. The composite layers are laminated without plasma treatment with a further plastic film in order to measure the lamination strength.

[0185] The lamination strength is measured according to JIS Z0238 with a Tensilon instron tester, at a speed: of 30 mm/min, the angle between the two films is 90 degree. As sealant (second film) LLDPE is used from Tohcello Co Ltd (TUX FCS), and as adhesive a 2 component polyurethane solvent based system from Mitsui Takeda Chemicals (Takelac A-515 and Takenate A50, which are mixed just before use).

[0186] The Oxygen transmission rate (OTR) is measured with OXTRAN 2/20 manufactured by Modern Control Cop, in an atmosphere of 30° C. and 70% RH.

TABLE-US-00001 OTR** Lamina- of Oligomeric tion com- organic strength posite Example compound Stabiliser* Thickness N/inch layer Comp None — 1.0 Not Exp deter- mined 1 Poly-ethylene A + B 200 nm 3.0 17 vinylalcohol (Mn 150000) 2 Poly-ethylene B 100 nm 2.5 13 vinylalcohol (Mn 100000) 3 PET (Mn 40000) C + D  10 nm 3.0 20 *Stabilizers used: A = Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); B = Octadecyl-3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate; C = Thiodiethylene bis[3-(3,5-di-tert.-butyl-4-hydroxy-phenyl)propionate]; D = Ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate): **OTR in cc/m.sup.2 .Math. 24 h

[0187] Part of the composite layer is dissolved in THF and the molecular weight of the oligomers in the solution is determined with gel chromatography. The molecular weights are on average (Mn) 3400, 7200 and 2800 respectively, and more than 90 wt % of the layer has a molecular weight below 20,000.

[0188] Thus, the polymers in the heating chamber are decomposed to a certain extent, to a form suitable for vapor deposition. The stabilizer in the polymer allows sufficiently long processing window that the full roll can be processed in a satisfactory manner.