US 2006/0134758 A1 · Process for obtaining a ccellulosic wet sheet and a membrane, the equipment used to obtain the membrane and the membrane obtained

Abstract

Said process used to obtain, in industrial scale, wet sheets and membranes of bacterial cellulose of high purity and specific physical and chemical properties, using the appropriate culture medium that is prepared in a mechanical mixer furnished with a jacket for temperature control and heat exchange, using selected recycled or non-recycled inoculums, fermentation in covered trays with the temperature controlled by an external heating/cooling jacket through the circulation of hot/cold water, not requiring control of humidity and air renovation, collecting of the wet sheets that are then submitted to a process of purification and whitening by successive whirlpool washing and rinsing cycles using diverse heated or non-heated aqueous solutions, being afterwards forwarded to draining and drying/dehydration, passing through a semi-continuous system of rollers and belt conveyors made of absorbent material. This invention also refers to the process used to obtain compounded cellulosic wet sheets. When a wet sheet reaches a certain thickness, screens or other artifacts of diverse materials are added to the surface of the wet sheet already pre-formed so that in a second fermentation stage such screens and artifacts are covered by the cellulosic wet sheet, thus forming a compound product.

Claims21

Dependent claims

“Process used to obtain cellulosic wet sheet” characterized by the following steps:

a) heating a solution containing 0.2 to 12% of glucose mass and 0.1 to 7% of yeast extract in water that was filtered through sand and activated charcoal, in a sanitary stainless steel mixer with a steam heated jacket, at a temperature of 125° C. for 15 minutes, for sterilization purposes;
b) cooling the solution till it reaches a temperature between 5 and 30° C.;
c) adding 0.5 to 5% of ethanol and of 2 to 50% of the inoculum Acetobacter xylinum, followed by agitation of the solution until it is homogenized;
d) transferring the solution to covered fermentation trays where it must rest for 16 to 240 hours, at a temperature between 5 and 30° C.;
e) collecting the cellulose wet sheets that are thus formed, varying from 0.25 to 200 mm in thickness;
f) forwarding the wet sheets to the whirlpool tank, where they are purified and whitened, according to the following sequence:
rinsing, washing with sodium hydroxide 1 to 5%, rinsing, washing with 1 to 5% sodium lauryl sulfate and final rinsing;
g). packaging the wet sheets for shipping.

5 more elements

Dependencies are inferred from the claim text.

Process for obtaining a ccellulosic wet sheet and a membrane, the equipment used to obtain the membrane and the membrane obtained

Life of this patent

Process for obtaining a ccellulosic wet sheet and a membrane, the equipment used to obtain the membrane and the membrane obtained

Life of this patent

Abstract

Claims21