Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/05—Filamentary, e.g. strands
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
  • B29C48/919—Thermal treatment of the stream of extruded material, e.g. cooling using a bath, e.g. extruding into an open bath to coagulate or cool the material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
  • B29C55/08—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique transverse to the direction of feed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D7/00—Producing flat articles, e.g. films or sheets
  • B29D7/01—Films or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/07—Flat, e.g. panels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
  • B29C48/10—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
  • B29K2001/08—Cellulose derivatives
  • B29K2001/12—Cellulose acetate
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2007/00—Flat articles, e.g. films or sheets
  • B29L2007/008—Wide strips, e.g. films, webs
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
  • C08J2301/02—Cellulose; Modified cellulose

Definitions

• the present invention deals with a process for the manufacture of cellulosic moulded bodies, in particular cellulosic flat films and cellulosic membranes in the form of flat membranes whereby a solution of cellulose in an aqueous tertiary amine oxide is moulded in film form by means of an extrusion die, which as an oblong extrusion gap, and led through an air gap into a precipitation bath whereby the cellulosic flat film is formed in the precipitation bath.
• a process for the production of cellulosic threads is, furthermore, known from DE-A-28 30 685 whereby a solution of cellulose is formed to filaments in a tertiary amine oxide in a warm condition, the filaments are cooled down with air and finally introduced to a precipitation bath to precipitate the dissolved cellulose.
• the surface of the spun filaments is, furthermore, moistened with water to reduce their tendency to stick to neighboring filaments.
• DE-C-44 21482 describes a blowing process for the manufacture of oriented cellulosic films whereby the cellulose solution is extruded via a film blowing nozzle and an air gap downwards into a precipitation bath. It is mentioned that stretching can be performed transverse to the transport direction of the blown film via the gas pressure in the inside of the blown film and that the relation of mechanical longitudinal and transverse properties can be set.
• a process and a device for the manufacture of cellulosic films, particularly of tubular films, is also known from WO-A-95/07811 of the applicant.
• the dissolved cellulose is cooled before it is brought into the precipitation bath by subjecting the heated solution to a stream of gas immediately after extruding.
• the permeability of the membranes is an important property. To solve certain separation tasks it is important to select membranes with the optimum permeability, pore size and pore structure for the respective separation task.
• Dialysis membranes made of regenerated cellulose in the form of flat films, tubular films or hollow threads have been known for some time whereby the regeneration of the cellulose can take place by means of the cuoxam-process, the viscose process or by means of the hydrolysis of cellulose acetate. Depending upon the process used and the process conditions one obtains membranes with different dialysis properties.
• U.S. Pat. No. 4,354,938 describes for example a process for the production of dialysis membranes according to the viscose process, in which a tubular moulded membrane is stretched in the transverse direction by between 40 and 120% by blowing up with air before drying, which leads to a membrane with a regular orientation in the longitudinal and transverse direction.
• a tubular moulded membrane is stretched in the transverse direction by between 40 and 120% by blowing up with air before drying, which leads to a membrane with a regular orientation in the longitudinal and transverse direction.
• the ultrafiltration values lie in the range of between 2.5 ml/m 2 .h.mm Hg and 5.2 ml/m 2 .h.mm Hg at a wet thickness of 184 ⁇ m to 45 ⁇ m.
• the present invention has as an object to provide a process for the production of cellulosic flat films with improved mechanical properties. Moreover, it is the object of the invention to provide a process for the production of cellulosic membranes in the form of flat membranes by means of which membranes with a permeability which is optimised for the individual separation task to be accomplished can be achieved.
• This object is achieved by a process for the production of cellulosic flat films and cellulosic membranes in the form of flat membranes whereby a solution of cellulose in an aqueous tertiary amine oxide is moulded in the form of a film using an extrusion nozzle which has an oblong extrusion gap, said solution being led through an air gap into a precipitation bath whereby the cellulosic flat film is formed in the precipitation bath, and in which according to the invention the cellulosic flat film is stretched in the transverse direction after entering the precipitation bath.
• transverse stretching can thereby take place in the precipitation bath or at a later time.
• transverse stretching is understood a stretching in the direction of the width of the cellulosic flat film.
• the transverse stretching of the films can be performed according to well known methods such as for example those used with thermoplastic films (as is for example described in the Handbook of Plastics Extrusion II, extrusion plants, Hanser-Verlag, 1986, 261-269), for example by conveyor belts or by clamping devices which are attached to endless belts respectively chains by the fact that the belts are led in divergent directions.
• the cellulose solution is extruded using an extrusion die, which has an extrusion gap with a length of at least 40 cm.
• the cellulose solution can, however, also be extruded from an extrusion gap with a length of less than 40 cm which results in films with a lower width.
• the extrusion die preferably includes an extrusion section. The cellulose solution flows out from the extrusion section into the extrusion gap.
• the length of the extrusion section is preferably greater than 1 mm, most preferably from about 5 mm to about 20 mm.
• the cellulosic flat film is stretched in the longitudinal direction in the air gap, preferably in a range of 0.2 to 5 times.
• One further advantageous embodiment of the process according to the invention is characterized in that the cellulose flat film is first washed after precipitation and stretched after washing.
• cellulosic flat films made using the process according to the invention can be stretched in the transverse direction in a washed state by up to 3.5 times their original width.
• the cellulosic flat film is first of all washed after precipitation and dried and after that the dry cellulosic flat film is moistened and stretched preferably by spraying with water. Surprisingly it was shown that cellulosic flat films treated in this way can be stretched by up to 3.5 times their original width in the transverse direction.
• the process according to the invention has the advantage that by stretching the cellulosic flat film up to 3.5 times the original width in the transverse direction the mechanical properties of the film can be set in a wide range in the longitudinal and transverse direction.
• N-Methylmorpholine-N-oxide is used as the tertiary amine oxide.
• the permeability of the membrane and thus also its ultrafiltration rate (UFR) can be influenced in particular by the selection of the speed at which the film-like moulded solution is drawn off in the air gap.
• UFR ultrafiltration rate
• a lower draw-off speed increases the permeability and thus also the ultrafiltration rate of the membrane.
• transverse stretching of the film after entering the precipitation bath increases the permeability of the membrane.
• basic membrane properties can be controlled by the selection of draw-off speed and the transverse stretching of the film.
• the invention also relates to the use of a cellulosic flat film made by the process in accordance with the invention as a package material, in particular for foodstuff, as a material for waste and carrier bags, as film for agricultural applications, as a film for diapers, as a substrate for compounds, as an office film, as a household film or as a membrane to separate substance mixtures.
• the cellulose solutions used were manufactured in accordance with the process described in EP-A-0 356 419.
• the films were washed following precipitation of the cellulose and treated with glycerine (glycerine content of the dried film about 15 wt. %) and finally dried on a tenter frame, in which the films were fixed in the longitudinal and transverse direction.
• the properties listed in the examples were determined with the dried films, whereby the tenacity (longitudinal and transverse) and the longitudinal and transverse elongation were determined according to DIN 53457.
• the ultrafiltration rate given in the examples is defined as the per time unit of the volume of the permeate passing through the membrane wall relative to the membrane area and test pressure.
• UFR V t ⁇ A ⁇ p ⁇ ml h ⁇ m 2 ⁇ mm ⁇ Hg
• V volume of liquid (permeate) [ml]
• A membrane area [m 2 ]
• A membrane area [cm 2 ]
• V dialysis volume [cm 3 ]
• the film-like moulded cellulose solution emerged from the nozzle at a speed of 4.2 mm/min and was drawn off with three times the emerging speed.
• the flat film obtained had the following properties:
• the flat film obtained had the following properties:
• the flat film obtained had the following properties:
• the flat film obtained had the following properties:
• the procedure was the same as in example 1 except that the flat film was stretched by 125% in the transverse direction on the tenter frame before drying.
• the flat film obtained had the following properties:
• the procedure was the same as in example 1 except that the flat film was stretched by 175% in the transverse direction before drying on the tenter frame.
• the flat film obtained had the following properties:
• the film-like moulded cellulose solution emerged from the nozzle at a speed of 4.2 m/min and was drawn off at the same speed. This means that the flat film was not stretched in the longitudinal direction in the air gap.
• the flat film obtained had the following properties:
• the flat film obtained had the following properties:
• the flat film obtained had the following properties:
• the film-like moulded cellulose solution emerged from the nozzle at a speed of 4.2 m/min and was drawn off at the same speed. This means that the flat film was not stretched in the air gap in the longitudinal direction.
• the flat film obtained had the following properties:
• the procedure was the same as in example 10 except that the flat film was moistened again after drying on the tenter frame and was stretched on the tenter frame by 100% in the transverse direction.
• the flat film obtained had the following properties in the dry state:
• the procedure was the same as in example 10 except that the flat film was moistened again after drying on the tenter frame and was stretched by 200% in the transverse direction on the tenter frame.
• the flat film obtained had the following properties in the dry state:
• the film-like moulded cellulose solution emerged from the nozzle with a speed of 4.2 m/min and was drawn off at the same speed. This means that the flat film was not stretched in the longitudinal direction in the air gap.
• the dry flat film was immersed in water for 2 minutes and afterwards was stretched on the tenter frame by 25% in the transverse direction.
• the film obtained had the following properties in the dry state:
• the procedure was the same as in example 13 except that the film immersed in the water was stretched on the tenter frame by 75% in the transverse direction.
• the flat film obtained had the following properties in the dry state:
• the film obtained had the following properties in the dry state:
• the flat film obtained had the following properties in the dry state:
• a cellophane film manufactured according to the viscose process was moistened and dried on the tenter frame without stretching.
• the film obtained had the following properties in the dry state:
• a cellophane film produced according to the viscose process was moistened and stretched in the transverse direction on the tenter frame by 50%. It was not possible to achieve a higher transverse stretching than 50% with the cellophane film without the film being torn.
• the film obtained had the following properties in the dry state:
• the film-like moulded cellulose solution emerged from the nozzle at a speed of 5.0 m/min and was drawn off at three times that speed and stretched in the precipitation bath in the transverse direction by 50%.
• the flat film obtained displayed the following properties:
• the film-like moulded cellulose solution emerged from the nozzle with a speed of 5.0 m/min and was drawn off with the same speed. After the precipitation bath the flat film was stretched in the transverse direction by 100%.
• the flat film obtained displayed the following properties:

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Health & Medical Sciences (AREA)
• Physics & Mathematics (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Thermal Sciences (AREA)
• Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Cell Separators (AREA)
• Laminated Bodies (AREA)

Priority Applications (1)

Applications Claiming Priority (7)

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Citations (25)

• 1998
  • 1998-04-24 BR BR9804868A patent/BR9804868A/pt not_active IP Right Cessation
  • 1998-04-24 ES ES98916620T patent/ES2232942T3/es not_active Expired - Lifetime
  • 1998-04-24 CA CA002258122A patent/CA2258122A1/fr not_active Abandoned
  • 1998-04-24 CN CNB988005409A patent/CN1142967C/zh not_active Expired - Fee Related
  • 1998-04-24 DE DE59812212T patent/DE59812212D1/de not_active Expired - Lifetime
  • 1998-04-24 EP EP98916620A patent/EP0912628B1/fr not_active Expired - Lifetime
  • 1998-04-24 JP JP54640298A patent/JP4375816B2/ja not_active Expired - Lifetime
  • 1998-04-24 AU AU70125/98A patent/AU7012598A/en not_active Abandoned
  • 1998-04-24 WO PCT/AT1998/000109 patent/WO1998049224A1/fr not_active Ceased
  • 1998-04-24 ID IDW980144D patent/ID21037A/id unknown
  • 1998-12-22 NO NO19986044A patent/NO321195B1/no unknown
• 2001
  • 2001-05-23 US US09/907,561 patent/USRE38583E1/en not_active Expired - Lifetime

Patent Citations (27)

Non-Patent Citations (2)

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