Laminate and process for its production
View Patent ↗To provide a laminate excellent in weather resistance, moisture-proof property, adhesion between layers and its long-term stability, and a process for its production. A laminate comprising a substrate sheet containing a fluororesin, an adhesive layer, and a moisture-proof layer containing, as the main component, at least one inorganic compound selected from the group consisting of an inorganic oxide, an inorganic nitride and an inorganic oxynitride, laminated in this order, wherein the adhesive layer contains, as the main component, at least one metal oxide selected from the group consisting of zirconium oxide, tantalum oxide and hafnium oxide.
1. A process for producing a laminate comprising a substrate sheet containing an ethylene/tetrafluoroethylene copolymer, an adhesive layer, and a moisture-proof layer containing at least 95 mol % of at least one inorganic compound selected from the group consisting of an inorganic oxide, an inorganic nitride and an inorganic oxynitride, laminated in this order, wherein the adhesive layer contains at least 95 mol % of at least one metal oxide selected from the group consisting of zirconium oxide, tantalum oxide and hafnium oxide, and wherein the thickness of the moisture-proof layer is at most 50 nm, said process comprising;
forming the adhesive layer on at least one side of the substrate sheet by a sputtering method in the presence of oxygen and argon, and
forming the moisture-proof layer on the adhesive layer by a dry method.
2. The process according to claim 1 , wherein the moisture-proof layer contains a Si compound or an Al compound as the inorganic compound.
3. The process according to claim 1 , wherein the moisture-proof layer contains aluminum oxide.
4. The process according to claim 1 , which has a visible light transmittance of at least 80%.
5. A protective sheet for a solar cell module comprising the laminate obtained by the process according to claim 1 .
6. The process according to claim 1 , wherein the argon and the oxygen, and are introduced into a reactor at a flow rate of 80:20 to 90:10.
7. The process according to claim 1 , wherein the thickness of the moisture-proof layer is at most 30 nm.
8. The process according to claim 1 , wherein the thickness of the adhesive layer is 0.5 to 20 nm.
9. The process according to claim 1 , wherein the thickness of the substrate sheet is 10 to 200 μm.
10. The process according to claim 1 , further comprising, before the forming of the adhesive layer on the substrate sheet, subjecting the substrate sheet to a surface treatment on the side where the adhesive layer is to be formed.
11. The process according to claim 10 , wherein the surface treatment is a plasma treatment or a corona discharge treatment.