CA2332041C - Process for continuously manufacturing composites of polymer and cellulosic fibres, and compounded materials obtained therewith - Google Patents
Process for continuously manufacturing composites of polymer and cellulosic fibres, and compounded materials obtained therewith Download PDFInfo
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- CA2332041C CA2332041C CA002332041A CA2332041A CA2332041C CA 2332041 C CA2332041 C CA 2332041C CA 002332041 A CA002332041 A CA 002332041A CA 2332041 A CA2332041 A CA 2332041A CA 2332041 C CA2332041 C CA 2332041C
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/08—Moulding or pressing
- B27N3/28—Moulding or pressing characterised by using extrusion presses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
- B29B7/46—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft
- B29B7/48—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft with intermeshing devices, e.g. screws
- B29B7/482—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft with intermeshing devices, e.g. screws provided with screw parts in addition to other mixing parts, e.g. paddles, gears, discs
- B29B7/483—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft with intermeshing devices, e.g. screws provided with screw parts in addition to other mixing parts, e.g. paddles, gears, discs the other mixing parts being discs perpendicular to the screw axis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
- B29B7/46—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft
- B29B7/48—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft with intermeshing devices, e.g. screws
- B29B7/488—Parts, e.g. casings, sealings; Accessories, e.g. flow controlling or throttling devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B7/00—Mixing; Kneading
- B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
- B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
- B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
- B29B7/46—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft
- B29B7/48—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft with intermeshing devices, e.g. screws
- B29B7/488—Parts, e.g. casings, sealings; Accessories, e.g. flow controlling or throttling devices
- B29B7/489—Screws
-
- 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
- B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of 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
- 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
- B29C48/256—Exchangeable extruder parts
- B29C48/2564—Screw parts
-
- 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
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
-
- 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
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
- B29C48/40—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
- B29C48/402—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders the screws having intermeshing parts
-
- 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
- B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
- B29C48/50—Details of extruders
- B29C48/505—Screws
- B29C48/55—Screws having reverse-feeding elements
-
- 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
-
- 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
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
Abstract
The present invention relates to a process for continuously manufacturing composites of polymer and cellulosic fibres, comprising the steps of: a) feeding a polymer upstream into an extruder; b) melting and mixing the polymer in a zone (A) of the extruder, wherein zone (A) comprises at least one positive transportation screw element; c) feeding cellulosic fibres into the extruder in a zone (B) of the extruder, which zone (B) is located downstream of zone (A); d) transporting the mixture of polymer and cellulosic fibre obtained in zone (B) through a degassing zone (C), which zone (C) is located downstream of zone (B), wherein zone (C) comprises at least one positive transportation screw element and e) transporting the mixture obtained in zone (C) through a pressure building zone (D) of the extruder, which zone (D) is located downstream of zone (C), wherein zone (D) comprises at least one positive transportation screw element; f) releasing the mixture obtained in zone (D) into a die, characterised in that zone (B) comprises at least one positive transportation screw element, at least one kneading section and at least one negative transportation screw element such that in zone (B) of the extruder the cellulosic fibres are fibrillated to obtain cellulosic fibres with an aspect ratio as high as possible, while simultaneously mixing the cellulosic fibres with the melted polymer. This process results in a compounded material comprising polymer and cellulosic fibres, wherein the cellulosic fibres are elementary fibres and have a high aspect ratio. As a result the compounded material has excellent mechanical properties.
Description
Process for continuously manufacturing composites of polymer and cellulosic fibres, and compounded materials obtained therewith The present invention relates to a process for continuously manufacturing composites of polymer and cellulosic fibres and to the compounded naaterial obtained therewith. It also relates to an extruder to be used in this process.
It is known to produce fibre reinforced plastics. For instance GB 1,151,964 describes a method for obtaining a plastics material reinforced witli brittle fibres such as glass fibres.
According to this method a brittle fibre substance is supplied as a continuous strand to the other components of the mixture in such a manner that ithe fibre breaks to a predetermined length. The apparatus used for this process comprises several mixing and kneading members which are not specified.
Lately, the focus on reinforcing fibres is shifting from glass fibres to certain kinds of cellulosic fibres which have outstanding intrinsic meclhanical properties.
These have the potential to compete with glass fibres as reinforcing agents in plastics. The specific strength of these agrofibres is 50 to 80 percent of lass fibres, whereas the specific modulus can exceed that of glass fibres. Supplementary benefits include low cost, low density, renewability and (bio)degradability. In addition, they are less abrasive during processing with thermoplastics and do not expose operators to potential safety or health problems.
A major disadvantage of cellulosic fibres is the limitecl temperature at which they should be processed without losing their additional mechanic;al properties. Further, it has been proven difficult to obtain a homogeneous mixture of polymer and fibre. This is mainly due to the non-polar polymeric surface versus the highly polar fibre surface which prevents satisfactory fibre/polymer intertwining.
EP 426,619 describes a method of producing panels from a thermoplastic polymer and a thermosensitive filler by means of an extruder having at least three feedingly effective helical extrusion sections and at least two non-feeding kneading sections. The extruder thus comprises at least two kneading zones and at least three extrusion zones.
The filler is preferably fed into the second extrusion zone.
When cellulosic fibres are used it is important that during the extrusion process these fibres obtain and maintain a high aspect ratio so as to obtain a compounded material with mechanical properties comparable with those of materials containing glass fibres. This means that the diameter should be as small as possible, preferably so called elementary fibres are used. Further the length of the fibres should be as large as possible.
Obtaining such a high aspect ratio of the fibres in the firial product has up to now not been achieved. The problem with extrusion processes according to the state of the art is that the high shear forces in the extruder often result not only in a smaller diameter of the fibres but also in a smaller length of the fibres. This reduces the strength properties of the compounded material considerably, relative to the glass fibre reinforced materials.
Accordingly, a substantial need exists for a continuous process for the production of polymer/cellulosic fibre composites with substantially improved mechanical properties, i.e. its rigidity and its strength. In addition, these result;ing property improvements should be valid for multiple fibre sources at broad polymer processing temperature ranges and independent from the polymeric melt behaviour.
The above objects are achieved by the present invention. The present invention relates to a process for continuously manufacturing composites of polymer and cellulosic fibres, comprising the steps of:
a) feeding a polymer upstream into an extruder;
b) melting and mixing the polymer in a zone (A) of the extruder; wherein zone (A) comprises at least one positive transportation screw element, c) feeding cellulosic fibres into the extruder in a zone (B) of the extruder, which zone (B) is located downstream of zone (A);
d) transporting the mixture of polymer and cellulosic fibre obtained in zone (B) through a degassing zone (C), which zone (C) is located downstream of zone (B), wherein zone (C) comprises at least one positive transportation screw element and e) transporting the mixture obtained in zone (C) through a pressure building zone (D) of the extruder, which zone (D) is located downstream of zone (C), wherein zone (D) comprises at least one positive transportation screw element.
f) releasing the mixture obtained in zone (D) into a die, characterised in that zone (B) comprises at least one positive transportation screw element, at least one kneading section and at least one negative transportatiori screw element such that in zone (B) of the extruder the cellulosic fibres are fibrillated to obtain cellulosic fibres with an aspect ratio as high as possible, while simultaneously mixing the cellulosic fibres with the melted polymer.
The design of this process is such that during the continuous mixing the cellulosic fibres are opened up to elementary fibres (fibrillation) with a high aspect ratio, which are homogeneously distributed in the polymeric melt. The process results in a compounded material with improved rigidity and strength.
The present invention also relates to an extruder which can be used to carry out the process. The present invention comprises all extruders with two separate feeding ports and a degassing port. The preferred extruder for perforrning the process of the present invention is a corotating twin-screw extruder. An example of such an extruder is a Berstorff ZE corotating twin-screw extruder with a length to diameter ratio varying from 35 to 40.
As indicated above, the extruder comprises four zones: a zone (A) where a polymer fed to the extruder is melted and mixed; a zone (B) where cellulosic fibres are fed to the extruder, fibrillated to elementary fibres and simultaneously mixed with the polymer; a zone (C) where the mixture of polymer and cellulosic fibre obtained in zone (B) is degassed and a zone (D) where pressure is built up.
According to the invention zone (A), which is the polymer melting and mixing zone, comprises at least one positive transportation screw element. Preferably zone (A) further comprises at least one kneading section and at least one negative transportation screw element. Preferably, zone (A) begins at a distance of 20 :X D calculated from the beginning of the die, wherein D stands for the diameter of the extrusion screw.
Generally zone (A) ends at a distance of 38 x D.
In this application the location of the zones is calculated from the beginning of the die, i.e.
from the end of the extruder. This is contrary to general practice in which these distances are calculated from the beginning of the extruder. This is done because according to the invention it is important that the feeding port for the fibres is located as close as possible to the end of the extruder.
Zone (A) can further be divided into four temperature zones. Zone (Al) defmes the feeding of the polymer. In this zone, which is generally located between 34 x D and 38 x D, the polymeric material is fed to the extruder. A conventional feeder in combination with a hopper are generally used for this purpose. After being fed to the extruder, the material is transported to zone (A2).
In zone (A2), which is generally located between 30 x D and 34 x D, the polymeric material starts to melt, predominantly by shear forces. From (A2) the material is transported to (A3), which is located between 24 x D and 30 x D. From this zone the polymer is transported to zone (A4) located between 24 x D and 20 x D. Both zone (A3) and (A4) serve to further melt and mix the polymer.
Zone (B), which is the fibre fibrillation and mixing zone, comprises at least one positive transportation screw element, at least one kneading section, preferably at least two kneading sections, and at least one negative transportation screw element.
Zone (B) is preferably located at a distance between 8 x D and 20 x D. The at least one kneading section of zone (B) is preferably located at a distance between 10 x D and 13 x D.
Zone (B) comprises two temperature zones: (BI) and (B2). In zone (B 1) the predried cellulosic fibres are continuously and gravimetrically fed in a conventional manner, for instance from a feeder to a hopper and further to the extruder. The position of this zone is between 14 x D and 20 x D. Preferably the fibres are fed at 16 x D. The amount of fibres fed is such that the weight ratio of the fibres in the final compounded material is controlled to a certain value. In addition the fibres start to be distributed in this zone.
In zone (B2) the fibres are fibrillated to elementary fibres. In addition the fibres are distributed homogeneously through the polymer matrix. If more than one positive transportation screw element is present in zone (B2), these elements preferably have a decreasing pitch in the flow direction of the polymer and fibre mixture. This zone is 5 locatedbetween8xDand 14xD.
Zone (C), the degassing zone, comprises at least oiie positive transportation screw element. In this zone water and other thermally unstable components are removed from the compounded mixture. For this purpose a conventional degassing port is present which is connected to a vacuum pump. At the end of this zone when the volatile substances have substantially been removed, binding of the fibres and matrix begins.
Zone (D) the pressure building zone, comprises at least one positive transportation screw element. Preferably this zone comprises at least two potsitive transportation elements. In .15 that case these elements have a decreasing pitch in the direction of the die. This results in an increase in pressure necessary to press the compounded material through the die.
In this zone further homogeneous distribution of the fibres into the matrix and compaction of the compounded material is accomplished resulting in the penetration of polymeric material into the surface pores and microcracks of the cellulosic fibres.
During this process both mechanical interlocking and chemical coupling of matrix and fibres are further increased resulting in optimised fibre/matrix interaction. Zone (D) comprises one temperature zone.
The temperatures of the different temperature zones described above depend upon the kind of polymer used. If the polymer is polyethylene, polypropylene or polystyrene, the following temperature profile may be applied.
It is known to produce fibre reinforced plastics. For instance GB 1,151,964 describes a method for obtaining a plastics material reinforced witli brittle fibres such as glass fibres.
According to this method a brittle fibre substance is supplied as a continuous strand to the other components of the mixture in such a manner that ithe fibre breaks to a predetermined length. The apparatus used for this process comprises several mixing and kneading members which are not specified.
Lately, the focus on reinforcing fibres is shifting from glass fibres to certain kinds of cellulosic fibres which have outstanding intrinsic meclhanical properties.
These have the potential to compete with glass fibres as reinforcing agents in plastics. The specific strength of these agrofibres is 50 to 80 percent of lass fibres, whereas the specific modulus can exceed that of glass fibres. Supplementary benefits include low cost, low density, renewability and (bio)degradability. In addition, they are less abrasive during processing with thermoplastics and do not expose operators to potential safety or health problems.
A major disadvantage of cellulosic fibres is the limitecl temperature at which they should be processed without losing their additional mechanic;al properties. Further, it has been proven difficult to obtain a homogeneous mixture of polymer and fibre. This is mainly due to the non-polar polymeric surface versus the highly polar fibre surface which prevents satisfactory fibre/polymer intertwining.
EP 426,619 describes a method of producing panels from a thermoplastic polymer and a thermosensitive filler by means of an extruder having at least three feedingly effective helical extrusion sections and at least two non-feeding kneading sections. The extruder thus comprises at least two kneading zones and at least three extrusion zones.
The filler is preferably fed into the second extrusion zone.
When cellulosic fibres are used it is important that during the extrusion process these fibres obtain and maintain a high aspect ratio so as to obtain a compounded material with mechanical properties comparable with those of materials containing glass fibres. This means that the diameter should be as small as possible, preferably so called elementary fibres are used. Further the length of the fibres should be as large as possible.
Obtaining such a high aspect ratio of the fibres in the firial product has up to now not been achieved. The problem with extrusion processes according to the state of the art is that the high shear forces in the extruder often result not only in a smaller diameter of the fibres but also in a smaller length of the fibres. This reduces the strength properties of the compounded material considerably, relative to the glass fibre reinforced materials.
Accordingly, a substantial need exists for a continuous process for the production of polymer/cellulosic fibre composites with substantially improved mechanical properties, i.e. its rigidity and its strength. In addition, these result;ing property improvements should be valid for multiple fibre sources at broad polymer processing temperature ranges and independent from the polymeric melt behaviour.
The above objects are achieved by the present invention. The present invention relates to a process for continuously manufacturing composites of polymer and cellulosic fibres, comprising the steps of:
a) feeding a polymer upstream into an extruder;
b) melting and mixing the polymer in a zone (A) of the extruder; wherein zone (A) comprises at least one positive transportation screw element, c) feeding cellulosic fibres into the extruder in a zone (B) of the extruder, which zone (B) is located downstream of zone (A);
d) transporting the mixture of polymer and cellulosic fibre obtained in zone (B) through a degassing zone (C), which zone (C) is located downstream of zone (B), wherein zone (C) comprises at least one positive transportation screw element and e) transporting the mixture obtained in zone (C) through a pressure building zone (D) of the extruder, which zone (D) is located downstream of zone (C), wherein zone (D) comprises at least one positive transportation screw element.
f) releasing the mixture obtained in zone (D) into a die, characterised in that zone (B) comprises at least one positive transportation screw element, at least one kneading section and at least one negative transportatiori screw element such that in zone (B) of the extruder the cellulosic fibres are fibrillated to obtain cellulosic fibres with an aspect ratio as high as possible, while simultaneously mixing the cellulosic fibres with the melted polymer.
The design of this process is such that during the continuous mixing the cellulosic fibres are opened up to elementary fibres (fibrillation) with a high aspect ratio, which are homogeneously distributed in the polymeric melt. The process results in a compounded material with improved rigidity and strength.
The present invention also relates to an extruder which can be used to carry out the process. The present invention comprises all extruders with two separate feeding ports and a degassing port. The preferred extruder for perforrning the process of the present invention is a corotating twin-screw extruder. An example of such an extruder is a Berstorff ZE corotating twin-screw extruder with a length to diameter ratio varying from 35 to 40.
As indicated above, the extruder comprises four zones: a zone (A) where a polymer fed to the extruder is melted and mixed; a zone (B) where cellulosic fibres are fed to the extruder, fibrillated to elementary fibres and simultaneously mixed with the polymer; a zone (C) where the mixture of polymer and cellulosic fibre obtained in zone (B) is degassed and a zone (D) where pressure is built up.
According to the invention zone (A), which is the polymer melting and mixing zone, comprises at least one positive transportation screw element. Preferably zone (A) further comprises at least one kneading section and at least one negative transportation screw element. Preferably, zone (A) begins at a distance of 20 :X D calculated from the beginning of the die, wherein D stands for the diameter of the extrusion screw.
Generally zone (A) ends at a distance of 38 x D.
In this application the location of the zones is calculated from the beginning of the die, i.e.
from the end of the extruder. This is contrary to general practice in which these distances are calculated from the beginning of the extruder. This is done because according to the invention it is important that the feeding port for the fibres is located as close as possible to the end of the extruder.
Zone (A) can further be divided into four temperature zones. Zone (Al) defmes the feeding of the polymer. In this zone, which is generally located between 34 x D and 38 x D, the polymeric material is fed to the extruder. A conventional feeder in combination with a hopper are generally used for this purpose. After being fed to the extruder, the material is transported to zone (A2).
In zone (A2), which is generally located between 30 x D and 34 x D, the polymeric material starts to melt, predominantly by shear forces. From (A2) the material is transported to (A3), which is located between 24 x D and 30 x D. From this zone the polymer is transported to zone (A4) located between 24 x D and 20 x D. Both zone (A3) and (A4) serve to further melt and mix the polymer.
Zone (B), which is the fibre fibrillation and mixing zone, comprises at least one positive transportation screw element, at least one kneading section, preferably at least two kneading sections, and at least one negative transportation screw element.
Zone (B) is preferably located at a distance between 8 x D and 20 x D. The at least one kneading section of zone (B) is preferably located at a distance between 10 x D and 13 x D.
Zone (B) comprises two temperature zones: (BI) and (B2). In zone (B 1) the predried cellulosic fibres are continuously and gravimetrically fed in a conventional manner, for instance from a feeder to a hopper and further to the extruder. The position of this zone is between 14 x D and 20 x D. Preferably the fibres are fed at 16 x D. The amount of fibres fed is such that the weight ratio of the fibres in the final compounded material is controlled to a certain value. In addition the fibres start to be distributed in this zone.
In zone (B2) the fibres are fibrillated to elementary fibres. In addition the fibres are distributed homogeneously through the polymer matrix. If more than one positive transportation screw element is present in zone (B2), these elements preferably have a decreasing pitch in the flow direction of the polymer and fibre mixture. This zone is 5 locatedbetween8xDand 14xD.
Zone (C), the degassing zone, comprises at least oiie positive transportation screw element. In this zone water and other thermally unstable components are removed from the compounded mixture. For this purpose a conventional degassing port is present which is connected to a vacuum pump. At the end of this zone when the volatile substances have substantially been removed, binding of the fibres and matrix begins.
Zone (D) the pressure building zone, comprises at least one positive transportation screw element. Preferably this zone comprises at least two potsitive transportation elements. In .15 that case these elements have a decreasing pitch in the direction of the die. This results in an increase in pressure necessary to press the compounded material through the die.
In this zone further homogeneous distribution of the fibres into the matrix and compaction of the compounded material is accomplished resulting in the penetration of polymeric material into the surface pores and microcracks of the cellulosic fibres.
During this process both mechanical interlocking and chemical coupling of matrix and fibres are further increased resulting in optimised fibre/matrix interaction. Zone (D) comprises one temperature zone.
The temperatures of the different temperature zones described above depend upon the kind of polymer used. If the polymer is polyethylene, polypropylene or polystyrene, the following temperature profile may be applied.
Zone Temperature ( C) Al 25to 160 A2 165 to 185 A3 190to210 A4 190 to 210 B 1 185 to 2,05 B2 180 to 200 C 180 to 200 D 185 to 205 The thermoplastic polymers that can be applied in the invention comprise "commodity"
plastics like low density polyethylene, high density polyethylene, poly(ethylene-copropylene), polypropylene (homopolymer and copolymer) and polystyrene (homopolymer, copolymer and terpolymers). In addition engineering plastics can be applied. Besides the virgin polymeric material, the recycled grades of the above-mentioned plastics are also applicable in the present invention.
A general definition of cellulosic fibres for the purpose of the present invention is 'any fibres were the main constituents are of plant tissue and whose main component consist of a-cellulose'. Preferably annual plant fibres or bast fibres, like flax, hemp, jute and kenaf are used. According to a different embodiment paper f:ibres such as recycled fibres from newspaper are used. It is also possible to use a comb:ination of different types of fibres such as paper fibres and bast fibres. Annual growth plant fibres can, by means of their intrinsic mechanical properties, generally compete with glass fibres.
Generally the raw cellulosic fibre bundles are between one and five millimetres in diameter. After being fibrillated during the compounding process, the cellulosic fibre diameter generally varies from ten to hundred micrometers, whereas the fibre aspect ratio varies from 7 to 100.
plastics like low density polyethylene, high density polyethylene, poly(ethylene-copropylene), polypropylene (homopolymer and copolymer) and polystyrene (homopolymer, copolymer and terpolymers). In addition engineering plastics can be applied. Besides the virgin polymeric material, the recycled grades of the above-mentioned plastics are also applicable in the present invention.
A general definition of cellulosic fibres for the purpose of the present invention is 'any fibres were the main constituents are of plant tissue and whose main component consist of a-cellulose'. Preferably annual plant fibres or bast fibres, like flax, hemp, jute and kenaf are used. According to a different embodiment paper f:ibres such as recycled fibres from newspaper are used. It is also possible to use a comb:ination of different types of fibres such as paper fibres and bast fibres. Annual growth plant fibres can, by means of their intrinsic mechanical properties, generally compete with glass fibres.
Generally the raw cellulosic fibre bundles are between one and five millimetres in diameter. After being fibrillated during the compounding process, the cellulosic fibre diameter generally varies from ten to hundred micrometers, whereas the fibre aspect ratio varies from 7 to 100.
The present process is especially suitable for a feed consisting of raw cellulosic fibres which is very economical. However, it is also possible to feed elementary fibres to the extruder. The present process is then advantageous because the elementary cellulosic fibres retain their high aspect ratio.
The amount of fibres fed to the extruders is such that in the final compounded material the fibre content is 5 wt.% to 50 wt.% based on the wei;ght of the compounded material, preferably 30 wt.% to 40 wt.%, most preferably 40 wt.%.
According to the present invention it is preferred to add a coupling agent to the polymeric material. With a coupling agent is meant a polymer which can be mixed with the polymer matrix and which can be chemically coupled onto the fibres. The preferred polymer to coupling agent ratio for a polyolefinic matrix (e.g. polyethylene, polypropylene) is 70 to 6, with a most preferred ratio of 8 to 16, based on weiglat. For the polystyrene matrix the preferred polymer to coupling agent ratio is 700 to 60, 450 to 550 being most preferred.
The preferred coupling agent for polyethylene is male:ic anhydride grafted polyethylene copolymer. The preferred coupling agent for polypropylene is maleic anhydride grafted polypropylene copolymer. The preferred coupling agent for polystyrene is maleic anhydride grafted polystyrene copolymer.
The coupling agent is preferably dry mixed with the polymer before being introduced into the extruder. For this purpose any conventional blende:r may be used. The mixture thus obtained is fed to the feeder as mentioned above. The polymer and coupling agent are homogeneously mixed in zone (A) of the extruder.
Other additives which can be added to the polymer comprise conventional additives such as pigments, antioxidants, fillers and flame retardants. Examples of fillers that may be used are talc, calcium carbonate and carbon black.
The mechanical properties of the compounded material according to the present invention compared with the properties of the polymer matrix are shown below.
The amount of fibres fed to the extruders is such that in the final compounded material the fibre content is 5 wt.% to 50 wt.% based on the wei;ght of the compounded material, preferably 30 wt.% to 40 wt.%, most preferably 40 wt.%.
According to the present invention it is preferred to add a coupling agent to the polymeric material. With a coupling agent is meant a polymer which can be mixed with the polymer matrix and which can be chemically coupled onto the fibres. The preferred polymer to coupling agent ratio for a polyolefinic matrix (e.g. polyethylene, polypropylene) is 70 to 6, with a most preferred ratio of 8 to 16, based on weiglat. For the polystyrene matrix the preferred polymer to coupling agent ratio is 700 to 60, 450 to 550 being most preferred.
The preferred coupling agent for polyethylene is male:ic anhydride grafted polyethylene copolymer. The preferred coupling agent for polypropylene is maleic anhydride grafted polypropylene copolymer. The preferred coupling agent for polystyrene is maleic anhydride grafted polystyrene copolymer.
The coupling agent is preferably dry mixed with the polymer before being introduced into the extruder. For this purpose any conventional blende:r may be used. The mixture thus obtained is fed to the feeder as mentioned above. The polymer and coupling agent are homogeneously mixed in zone (A) of the extruder.
Other additives which can be added to the polymer comprise conventional additives such as pigments, antioxidants, fillers and flame retardants. Examples of fillers that may be used are talc, calcium carbonate and carbon black.
The mechanical properties of the compounded material according to the present invention compared with the properties of the polymer matrix are shown below.
Material Stiffness [GPa] Strength [MPa]
PP 1.2 41 PP/cellulose fibre 5.8 95 LDPE 0.1 6 LDPE/cellulose fibre 1.6 28 HDPE 0.9 20 HDPE/cellulose fibre 3.5 47 PS 1.9 40 PS/cellulose fibre 6.0 65 PP = polypropylene LDPE = low density polyethylene HDPE = high density polyethylene PS = polystyrene % cellulose fibre = 40 % by weight The compounded material exiting the die may be granulated before being further processed. These granules can be formed into articles by means of thermoforming processing techniques such as injection molding and. compression molding. It is also possible to directly mould the compounded material obtained into sheets, tubes, profiles, etc. The articles obtained from the compounded material may serve to replace wood, plastic and alternatively filled- or reinforced composite alternatives.
The invention shall now be described in more detail by means of the annexed drawing.
According to the present process a polymer is fed to the extruder at feeding port (21), (zone A 1). Before feeding, the polymer is preferably mixed with a coupling agent in a blender (not shown), added to a feeder (not shoNAm) and the dry mixture is then gravimetrically fed from the feeder through a hopper (not shown) into the extruder (20).
PP 1.2 41 PP/cellulose fibre 5.8 95 LDPE 0.1 6 LDPE/cellulose fibre 1.6 28 HDPE 0.9 20 HDPE/cellulose fibre 3.5 47 PS 1.9 40 PS/cellulose fibre 6.0 65 PP = polypropylene LDPE = low density polyethylene HDPE = high density polyethylene PS = polystyrene % cellulose fibre = 40 % by weight The compounded material exiting the die may be granulated before being further processed. These granules can be formed into articles by means of thermoforming processing techniques such as injection molding and. compression molding. It is also possible to directly mould the compounded material obtained into sheets, tubes, profiles, etc. The articles obtained from the compounded material may serve to replace wood, plastic and alternatively filled- or reinforced composite alternatives.
The invention shall now be described in more detail by means of the annexed drawing.
According to the present process a polymer is fed to the extruder at feeding port (21), (zone A 1). Before feeding, the polymer is preferably mixed with a coupling agent in a blender (not shown), added to a feeder (not shoNAm) and the dry mixture is then gravimetrically fed from the feeder through a hopper (not shown) into the extruder (20).
The polymeric material starts to melt, predominantly by shear forces, as it is transported through zone (A2). In zone (A3) the material is further :melted; in addition both polymer and coupling agent are homogeneously mixed, whilst potential temperature differences have vanished to a large extend. Distributive mixing of the coupling agent in the polymeric matrix is further optimised in zone (A4):
In zone (B 1) predried cellulosic fibres are continuously a.nd gravimetrically fed at feeding port (22) from a feeder to a hopper (not shown). In tlus zone the cellulosic fibres are introduced into the polymeric melt. In zone (B2), the fibres are virtually fibrillated to elementary fibres in the kneading section. In addition the fibres start to be distributed in this zone.
Following the transporting screw elements with decreasing pitch, resulting in increasing pressure in zone (B2), the fibres are further homogenecrusly distributed in the polymeric matrix. In zone (C) water and other thermally unstable components are removed from the compounded mixture in degassing port (23), to a vacuum pump (not shown). With the volatiles being removed chemical coupling of fibres and :matrix preferably starts.
In zone (D) homogeneous distribution of the fibres into the matrix and compaction of the compounded material is accomplished resulting in the penetration of (maleic anhydride grafted) polymeric material into the surface pores and microcracks of the cellulosic fibres.
During this process both mechanical interlocking and chemical coupling of matrix and fibres are further increased resulting in optimised fibre/matrix interaction.
Since the cellulosic fibres are introduced in to the polyineric melt as late as possible, the fibrillated material is the least affected by friction and heat. As a result the fibre aspect ratio remains as high as possible under the described processing conditions, which leads (in combination with optimised chemical and mechanical fibre/matrix coupling) to substantially improved material stiffness and strength properties.
Examples Several screw configurations were used to prepare a niixture of polymer and fibre. The extruder was a Berstorff ZE corotating twin-screw extruder. For each example the extruder compounding conditions were, unless indicated otherwise., screw speed 200 rpm melt temperature 195 'C
5 matrix material polypropylene homopolymer MFI230,2.16 = 12 g/10 min.
fibre content 30 wt.%
fibre type kenaf (except example 5) For all examples the fibre length and the percentage of fibres still present as a bundle of 10 the agrofibres in the matrix material was determined. The fibre dimension is an indication of the rigidity and strength of the final material. In order to determine fibre length the agrofibres were extracted from extruder compounded PP/fibre granules using soxlhet extraction with decaline as the solvent. Agrofibre-length measurements were performed at a Kajaani FS-200 following Tappi T271 prn-91.
Example 1 (comparative) For this example a screw configuration according to the following table was used:
Screw Type SW SW SW KB KB RSE SW SW SW
Amount 6 1 1 1 1 1 14 1 3 Length (mm) 60 40 30 50 30 20 60 40 30 Transport + + + + - - + + +
Pitch (mm) 60 40 30 100 60 40 60 40 30 In this table SW stands for Self Wiping, KB stands for Kneading Block and RSE
stands for Reverse Screw Element.
The fibre lengths could not be measured due to a stagnating extruder. This was caused by large numbers of unopened fibre bundles, which constipated the extruder die.
In zone (B 1) predried cellulosic fibres are continuously a.nd gravimetrically fed at feeding port (22) from a feeder to a hopper (not shown). In tlus zone the cellulosic fibres are introduced into the polymeric melt. In zone (B2), the fibres are virtually fibrillated to elementary fibres in the kneading section. In addition the fibres start to be distributed in this zone.
Following the transporting screw elements with decreasing pitch, resulting in increasing pressure in zone (B2), the fibres are further homogenecrusly distributed in the polymeric matrix. In zone (C) water and other thermally unstable components are removed from the compounded mixture in degassing port (23), to a vacuum pump (not shown). With the volatiles being removed chemical coupling of fibres and :matrix preferably starts.
In zone (D) homogeneous distribution of the fibres into the matrix and compaction of the compounded material is accomplished resulting in the penetration of (maleic anhydride grafted) polymeric material into the surface pores and microcracks of the cellulosic fibres.
During this process both mechanical interlocking and chemical coupling of matrix and fibres are further increased resulting in optimised fibre/matrix interaction.
Since the cellulosic fibres are introduced in to the polyineric melt as late as possible, the fibrillated material is the least affected by friction and heat. As a result the fibre aspect ratio remains as high as possible under the described processing conditions, which leads (in combination with optimised chemical and mechanical fibre/matrix coupling) to substantially improved material stiffness and strength properties.
Examples Several screw configurations were used to prepare a niixture of polymer and fibre. The extruder was a Berstorff ZE corotating twin-screw extruder. For each example the extruder compounding conditions were, unless indicated otherwise., screw speed 200 rpm melt temperature 195 'C
5 matrix material polypropylene homopolymer MFI230,2.16 = 12 g/10 min.
fibre content 30 wt.%
fibre type kenaf (except example 5) For all examples the fibre length and the percentage of fibres still present as a bundle of 10 the agrofibres in the matrix material was determined. The fibre dimension is an indication of the rigidity and strength of the final material. In order to determine fibre length the agrofibres were extracted from extruder compounded PP/fibre granules using soxlhet extraction with decaline as the solvent. Agrofibre-length measurements were performed at a Kajaani FS-200 following Tappi T271 prn-91.
Example 1 (comparative) For this example a screw configuration according to the following table was used:
Screw Type SW SW SW KB KB RSE SW SW SW
Amount 6 1 1 1 1 1 14 1 3 Length (mm) 60 40 30 50 30 20 60 40 30 Transport + + + + - - + + +
Pitch (mm) 60 40 30 100 60 40 60 40 30 In this table SW stands for Self Wiping, KB stands for Kneading Block and RSE
stands for Reverse Screw Element.
The fibre lengths could not be measured due to a stagnating extruder. This was caused by large numbers of unopened fibre bundles, which constipated the extruder die.
Example 2 ("heavy" fibre mixing and opening) For this example a screw configuration according to the following table was used:
Screw SW SW SW KB KB RSE SW KB KB
Type Amount 6 1 1 1 1 1 7 1 1 Length 60 40 30 50 30 20 60 30' 30 mm) Transport + + + + - - + + +
Pitch 60 40 30 100 60 40 60 60 60 (mm) [continued.]
Screw KB RSE SW SW SW KB KB RSE SW SW
Type Amount 1 1 3 1 1 1 1 1 1 3 Length 30 20 60 30 20 30 30 20 40 30 (mm Transport - - + + + + - - + +
Pitch 60 40 60 20 20 60 60 40 40 30 mm) The results of this example are indicated in Table 1.
Example 3 (optimal fibre mixing and opening) For this example a screw configuration according to the following table was used:
Screw type SW SW SW KB KB RSE SW KB KB RSF SW SW SW KB SW SW SW
Amount 6 1 1 1 1 1 7 1 1 1 1 I 1 f 3 1 3 Length (mm) 60 40 30 50 30 20 60 30 30 20 60 40 30 30 60 40 30 Transport + + + + - - + + - - -r- + + + + + +
Pitch (mm) 60 40 30 100 60 40 60 60 60 40 60 40 30 60 60 40 30 The results of this example are indicated in Table 1.
Example 4 (batch kneader) The compound preparation was performed by batch kneading on a HAAKE Rheomix 3000 equiped with roller rotors. The Rheomix was operated at 185 C and 100 RPM.
The PP granulate was added first and kneaded for 2 minutes, followed by the introduction of the kenaf fibres. This which was kneaded for 7 minutes, after which a composite material with homogeneously dispersed fibres was produced.
Example 5 Example 3 was repeated with the exception that flax jF'ibres were used instead of kenaf fibres. The results are indicated in Table 1.
Table 1 Arithmic Length weighted aver-age number of bundled Example average fibres mm [mm] 1%
1 innumerable 2 1.17 1.63 19 3 1.51 1.93 22 4 0.28 0.44 1 5 0.63 1.43 not measured
Screw SW SW SW KB KB RSE SW KB KB
Type Amount 6 1 1 1 1 1 7 1 1 Length 60 40 30 50 30 20 60 30' 30 mm) Transport + + + + - - + + +
Pitch 60 40 30 100 60 40 60 60 60 (mm) [continued.]
Screw KB RSE SW SW SW KB KB RSE SW SW
Type Amount 1 1 3 1 1 1 1 1 1 3 Length 30 20 60 30 20 30 30 20 40 30 (mm Transport - - + + + + - - + +
Pitch 60 40 60 20 20 60 60 40 40 30 mm) The results of this example are indicated in Table 1.
Example 3 (optimal fibre mixing and opening) For this example a screw configuration according to the following table was used:
Screw type SW SW SW KB KB RSE SW KB KB RSF SW SW SW KB SW SW SW
Amount 6 1 1 1 1 1 7 1 1 1 1 I 1 f 3 1 3 Length (mm) 60 40 30 50 30 20 60 30 30 20 60 40 30 30 60 40 30 Transport + + + + - - + + - - -r- + + + + + +
Pitch (mm) 60 40 30 100 60 40 60 60 60 40 60 40 30 60 60 40 30 The results of this example are indicated in Table 1.
Example 4 (batch kneader) The compound preparation was performed by batch kneading on a HAAKE Rheomix 3000 equiped with roller rotors. The Rheomix was operated at 185 C and 100 RPM.
The PP granulate was added first and kneaded for 2 minutes, followed by the introduction of the kenaf fibres. This which was kneaded for 7 minutes, after which a composite material with homogeneously dispersed fibres was produced.
Example 5 Example 3 was repeated with the exception that flax jF'ibres were used instead of kenaf fibres. The results are indicated in Table 1.
Table 1 Arithmic Length weighted aver-age number of bundled Example average fibres mm [mm] 1%
1 innumerable 2 1.17 1.63 19 3 1.51 1.93 22 4 0.28 0.44 1 5 0.63 1.43 not measured
Claims (17)
1. Process for continuously manufacturing composites of polymer and cellulosic fibres, comprising the steps of:
a) feeding a polymer upstream into an extruder;
b) melting and mixing the polymer in a zone A of the extruder; wherein zone A
comprises at least one positive transportation screw element, c) feeding cellulosic fibres into the extruder in a zone B of the extruder, which zone B is located downstream of zone A;
d) transporting the mixture of polymer and cellulosic fibre obtained in zone B
through a degassing zone C, which zone C is located downstream of zone B, wherein zone C comprises at least one positive transportation screw element and e) transporting the mixture obtained in zone C through a pressure building zone D
of the extruder, which zone D is located downstream of zone C, wherein zone D
comprises at least one positive transportation screw element.
f) pressing the mixture obtained in zone D into a die, characterised in that zone B comprises at least one positive transportation screw element, at least one kneading section and at least one negative transportation screw element such that in zone B of the extruder the cellulosic fibres are fibrillated to obtain cellulosic fibres with an aspect ratio from 7 to 100, while simultaneously mixing the cellulosic fibres with the melted polymer.
a) feeding a polymer upstream into an extruder;
b) melting and mixing the polymer in a zone A of the extruder; wherein zone A
comprises at least one positive transportation screw element, c) feeding cellulosic fibres into the extruder in a zone B of the extruder, which zone B is located downstream of zone A;
d) transporting the mixture of polymer and cellulosic fibre obtained in zone B
through a degassing zone C, which zone C is located downstream of zone B, wherein zone C comprises at least one positive transportation screw element and e) transporting the mixture obtained in zone C through a pressure building zone D
of the extruder, which zone D is located downstream of zone C, wherein zone D
comprises at least one positive transportation screw element.
f) pressing the mixture obtained in zone D into a die, characterised in that zone B comprises at least one positive transportation screw element, at least one kneading section and at least one negative transportation screw element such that in zone B of the extruder the cellulosic fibres are fibrillated to obtain cellulosic fibres with an aspect ratio from 7 to 100, while simultaneously mixing the cellulosic fibres with the melted polymer.
2. Process according to claim 1, wherein zone A further comprises a kneading section and at least one negative transportation screw element.
3. Process according to claim 1 or 2, wherein zone B comprises at least two kneading sections.
4. Process according to any of claims 1 to 3, wherein zone D comprises at least two positive transportation screw elements with decreasing pitch towards the die.
5. Process according to any one of claims 1 to 4, wherein the cellulosic fibres are bast fibres and/or paper fibres.
6. Process according to any one of claims 1 to 5, wherein a coupling agent is mixed with the polymer before feeding the polymer to the extruder.
7. Process according to any of claims 1 to 6, wherein the fibres are gravimetrically fed in such an amount as to obtain a final compounded material containing 5 to 50 wt.%, preferably 30 to 40 wt.% fibres on the basis of the weight of the compounded material.
8. Process according to any of claims 1 to 7, wherein the extruder is a corotating twin-screw extruder.
9. Compounded material obtainable by the process according to any of claims 1 to 8.
10. Extruder for continuously manufacturing composites of polymer and cellulosic fibres connected to means for feeding a polymer, means for feeding cellulosic fibres and means for degassing the extruder, comprising:
a zone A where a polymer fed to the extruder is melted and mixed, comprising at least one positive transportation screw element, a zone B where cellulosic fibres are fed to the extruder, fibrillated and simultaneously mixed with the polymer, comprising at least one positive transportation screw element, at least one kneading section and at least one negative transportation screw element, a zone C where the mixture of polymer and cellulosic fibre obtained in zone B
is degassed, comprising at least one positive transportation screw element, a zone D where pressure is built up, comprising at least one positive transportation screw element and a die.
a zone A where a polymer fed to the extruder is melted and mixed, comprising at least one positive transportation screw element, a zone B where cellulosic fibres are fed to the extruder, fibrillated and simultaneously mixed with the polymer, comprising at least one positive transportation screw element, at least one kneading section and at least one negative transportation screw element, a zone C where the mixture of polymer and cellulosic fibre obtained in zone B
is degassed, comprising at least one positive transportation screw element, a zone D where pressure is built up, comprising at least one positive transportation screw element and a die.
11. Extruder according to claim 10, wherein zone A further comprises a kneading section and at least one negative transportation screw element, zone B
comprises at least two kneading sections and zone D comprises at least two positive transportation screw elements with decreasing pitch towards the die.
comprises at least two kneading sections and zone D comprises at least two positive transportation screw elements with decreasing pitch towards the die.
12. Extruder according to claim 10 or 11, which is a corotating twin-screw extruder.
13. Extruder according to any one of claims 10 to 12, wherein zone B is located at a distance between 8 × D and 20 × D calculated from the beginning of the die, D being the diameter of the screw.
14. Extruder according to any one of claims 10 to 13, wherein the fibres are fed into the extruder at a distance between 14 × D and 20 × D, preferably 16 × D, calculated from the beginning of the die.
15. Extruder according to any one of claims 10 to 14, wherein the at least one kneading section of zone B is located at a distance between 10 × D and 13 × D, calculated from the beginning of the die.
16. Extruder according to any one of claims 10 to 15, wherein zone C is located at a distance between 4 .CHI. D and 8 × D calculated from the beginning of the die.
17. Extruder according to any one of claims 10 to 16, wherein zone D is located at a distance between 0 × D and 4 × D calculated from the beginning of the die.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP98201497 | 1998-05-07 | ||
| EP98201497.9 | 1998-05-07 | ||
| PCT/NL1999/000282 WO1999056936A1 (en) | 1998-05-07 | 1999-05-07 | Process for continuously manufacturing composites of polymer and cellulosic fibres, and compounded materials obtained therewith |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2332041A1 CA2332041A1 (en) | 1999-11-11 |
| CA2332041C true CA2332041C (en) | 2007-07-17 |
Family
ID=8233693
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002332041A Expired - Fee Related CA2332041C (en) | 1998-05-07 | 1999-05-07 | Process for continuously manufacturing composites of polymer and cellulosic fibres, and compounded materials obtained therewith |
Country Status (13)
| Country | Link |
|---|---|
| US (1) | US6565348B1 (en) |
| EP (1) | EP1075377B1 (en) |
| JP (1) | JP4365529B2 (en) |
| CN (1) | CN1168591C (en) |
| AT (1) | ATE251021T1 (en) |
| AU (1) | AU3853599A (en) |
| CA (1) | CA2332041C (en) |
| DE (1) | DE69911762T2 (en) |
| DK (1) | DK1075377T3 (en) |
| ES (1) | ES2203130T3 (en) |
| PT (1) | PT1075377E (en) |
| SI (1) | SI1075377T1 (en) |
| WO (1) | WO1999056936A1 (en) |
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| WO2024069509A1 (en) * | 2022-09-30 | 2024-04-04 | Plastik Textile S.P.A. | A mixing apparatus and a filming plant comprising said apparatus |
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| US3453356A (en) * | 1964-02-24 | 1969-07-01 | Dow Chemical Co | Mixing of filamentary reinforcing material with thermoplastic resins |
| DE1502335B2 (en) * | 1965-02-13 | 1971-10-21 | Werner & Pfleiderer, 7000 Stuttgart | SCREW EXTRUSION PRESS FOR THE PROCESSING OF PLASTIC |
| US3409711A (en) * | 1965-11-01 | 1968-11-05 | Dow Chemical Co | Method and apparatus for the preparation of filament reinforced synthetic resinous material |
| GB1151964A (en) * | 1966-03-08 | 1969-05-14 | Werner & Pfleiderer | Method and Apparatus for the Continuous Preparation of Plastics Material Mixtures |
| US4329313A (en) * | 1980-11-12 | 1982-05-11 | Union Carbide Corporation | Apparatus and method for extruding ethylene polymers |
| JPS58110233A (en) | 1981-12-24 | 1983-06-30 | Toshiba Mach Co Ltd | Manufacturing device for metal fiber-reinforced plastic |
| JPS59167240A (en) | 1983-03-14 | 1984-09-20 | Chisso Corp | Method and apparatus for manufacturing molding of organic filler-mixed thermoplastic resin composition |
| DE3309007C2 (en) * | 1983-03-14 | 1986-01-30 | AUTOMATIK Apparate-Maschinenbau GmbH, 8754 Großostheim | Method and device for producing thermoplastic material to be filled with reinforcing fibers |
| US4663103A (en) * | 1983-08-09 | 1987-05-05 | Collins & Aikman Corporation | Apparatus and method of extrusion |
| US4848915A (en) * | 1988-04-25 | 1989-07-18 | E. I. Du Pont De Nemours And Company | Process for metering color concentrates to thermoplastic polymer melts |
| EP0342839B1 (en) * | 1988-05-17 | 1994-01-26 | The Japan Steel Works, Ltd. | Extruder having degree-of-kneading adjusting device |
| JPH0615170B2 (en) * | 1989-04-27 | 1994-03-02 | 東芝機械株式会社 | Twin screw extruder for dehydration / dry molding of thermoplastic resin |
| IT1237672B (en) | 1989-10-31 | 1993-06-15 | Gian Carlo Colombo | METHOD TO PRODUCE REPRINTABLE PANELS. |
| DE4016784A1 (en) * | 1990-05-25 | 1991-11-28 | Werner & Pfleiderer | EXTRUDER FOR PROCESSING PLASTIC BY FEEDING AT LEAST ONE STRING OF FIBER |
| DE4039943A1 (en) * | 1990-12-14 | 1992-06-17 | Berstorff Gmbh Masch Hermann | METHOD AND DEVICE FOR THE UNIFORM, CONTINUOUS MANUFACTURE OF A RUBBER-BASED AND FINISHED MIXTURE FOR VEHICLE TIRES, DRIVE BELTS, TRANSPORT BELTS AND TECHNICAL RUBBER PRODUCTS IN ONLY ONE MIXING DEVICE |
| FR2683483B1 (en) * | 1991-11-08 | 1995-02-24 | Vetrotex France Sa | METHOD FOR MANUFACTURING A COMPOSITE PRODUCT BY MOLDING. |
| US5738935A (en) * | 1993-08-30 | 1998-04-14 | Formtech Enterprises, Inc. | Process to make a composite of controllable porosity |
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-
1999
- 1999-05-07 WO PCT/NL1999/000282 patent/WO1999056936A1/en active IP Right Grant
- 1999-05-07 EP EP99921289A patent/EP1075377B1/en not_active Expired - Lifetime
- 1999-05-07 ES ES99921289T patent/ES2203130T3/en not_active Expired - Lifetime
- 1999-05-07 PT PT99921289T patent/PT1075377E/en unknown
- 1999-05-07 US US09/674,828 patent/US6565348B1/en not_active Expired - Fee Related
- 1999-05-07 CN CNB998069736A patent/CN1168591C/en not_active Expired - Fee Related
- 1999-05-07 CA CA002332041A patent/CA2332041C/en not_active Expired - Fee Related
- 1999-05-07 DE DE69911762T patent/DE69911762T2/en not_active Expired - Lifetime
- 1999-05-07 DK DK99921289T patent/DK1075377T3/en active
- 1999-05-07 JP JP2000546934A patent/JP4365529B2/en not_active Expired - Fee Related
- 1999-05-07 AU AU38535/99A patent/AU3853599A/en not_active Abandoned
- 1999-05-07 SI SI9930388T patent/SI1075377T1/en unknown
- 1999-05-07 AT AT99921289T patent/ATE251021T1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| AU3853599A (en) | 1999-11-23 |
| WO1999056936A1 (en) | 1999-11-11 |
| ES2203130T3 (en) | 2004-04-01 |
| US6565348B1 (en) | 2003-05-20 |
| PT1075377E (en) | 2004-02-27 |
| SI1075377T1 (en) | 2003-12-31 |
| JP4365529B2 (en) | 2009-11-18 |
| CN1304350A (en) | 2001-07-18 |
| ATE251021T1 (en) | 2003-10-15 |
| EP1075377A1 (en) | 2001-02-14 |
| DE69911762D1 (en) | 2003-11-06 |
| DK1075377T3 (en) | 2004-01-19 |
| CA2332041A1 (en) | 1999-11-11 |
| DE69911762T2 (en) | 2004-04-29 |
| CN1168591C (en) | 2004-09-29 |
| JP2002513692A (en) | 2002-05-14 |
| EP1075377B1 (en) | 2003-10-01 |
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