Method for preparing a membrane from fibril cellulose and fibril, cellulose membrane
AssigneeUpm-Kymmene Corporation
InventorsMarko Bessonoff, Jouni Paltakari, Antti Laukkanen
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Abstract
Method for preparing a membrane from fibril cellulose includes supplying fibril cellulose dispersion on a filter layer, draining liquid from a fibril cellulose dispersion by the effect of reduced pressure through the filter layer that is impermeable to fibrils of the fibril cellulose but permeable to the liquid to form a membrane sheet on the filter fabric, applying heat on the opposite side of the membrane sheet to the membrane sheet while continuing draining of the liquid through the filter layer by pressure difference over the filter layer, and removing the membrane sheet from the filter layer as a freestanding membrane.
Claims29
A method for preparing a nanofibrillar cellulose membrane, the method comprising:
- supplying a nanofibrillar cellulose dispersion on a filter layer;
- draining liquid from the nanofibrillar cellulose dispersion by the effect of reduced pressure through the filter layer that is impermeable to fibrils of the nanofibrillar cellulose but permeable to the liquid to form a membrane sheet on the filter layer;
- continuing draining the liquid from the nanofibrillar cellulose while applying heat to a side of the membrane sheet opposite the filter layer to promote the removal of the liquid in liquid state while continuing draining of the liquid through the filter layer by pressure difference over the filter layer;
- and
- subsequent to the heat application, removing the membrane sheet from the filter layer as the nanofibrillar cellulose membrane, the nanofibrillar cellulose membrane being freestanding.
A method of forming a fibril cellulose membrane laminate, the method comprising:
- supplying a nanofibrillar cellulose dispersion on a filter layer;
- draining liquid from the nanofibrillar cellulose dispersion by the effect of reduced pressure through the filter layer that is impermeable to fibrils of the nanofibrillar cellulose but permeable to the liquid to form a membrane sheet on the filter layer;
- continuing draining the liquid from the nanofibrillar cellulose while applying heat to a side of the membrane sheet opposite the filter layer by contact of a heated surface with a layer interposed between the heated surface and the membrane sheet to promote the removal of the liquid in liquid state while continuing draining of the liquid through the filter layer by pressure difference over the filter layer, the layer interposed between the heated surface and the membrane sheet being a filter fabric or a structural layer;
- subsequent to the heat application, removing the membrane sheet from the filter layer as the nanofibrillar cellulose membrane, the nanofibrillar cellulose membrane being freestanding.
A method of forming a fibril cellulose membrane laminate, the method comprising:
- supplying a nanofibrillar cellulose dispersion on a filter layer;
- draining liquid from the nanofibrillar cellulose dispersion by the effect of reduced pressure through the filter layer that is impermeable to fibrils of the nanofibrillar cellulose but permeable to the liquid to form a membrane sheet on the filter layer;
- continuing draining the liquid from the nanofibrillar cellulose while applying heat to a side of the membrane sheet opposite the filter layer to promote the removal of the liquid in liquid state while continuing draining of the liquid through the filter layer by pressure difference over the filter layer;
- subsequent to the heat application, removing the membrane sheet from the filter layer as the nanofibrillar cellulose membrane, the nanofibrillar cellulose membrane being freestanding;
- and
- laminating a structural material to the membrane sheet, the structural material including plastic films, cardboard, or paper.
Dependencies are inferred from the claim text.