Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
  • G01N11/02—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by measuring flow of the material
  • G01N11/04—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by measuring flow of the material through a restricted passage, e.g. tube, aperture
• • 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
  • B29C48/69—Filters or screens for the moulding material
  • B29C48/693—Substantially flat filters mounted at the end of an extruder screw perpendicular to the feed axis
• • 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
  • B29C48/92—Measuring, controlling or regulating
• • 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
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92504—Controlled parameter
  • B29C2948/92514—Pressure
• • 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
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92819—Location or phase of control
  • B29C2948/92857—Extrusion unit
  • B29C2948/92876—Feeding, melting, plasticising or pumping zones, e.g. the melt itself
• • 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

Definitions

• the present invention relates to an apparatus for carrying out the pressure filter test on a material formed by mixing a filler and/or a pigment with a polymer matrix, and to the associated test procedure.
• the pressure filter test has been used commonly and widely for many years in the plastics industry for assessing how well fillers and/or pigments are dispersed in a polymer matrix .
• a small amount of material already mixed in a process extruder is diluted with virgin polymer, extruded in another suitable extruder and then passed through a filter by the action of a gear pump mounted downstream of the extruder head.
• a sensor records the pressure increase caused by the progressive deposition, on the surface of the filter, of particles of filler and/or pigment that have not mixed perfectly in the polymer matrix .
• the value of the parameter measured at the end of the test is thus determined by the time taken to reach a given pressure increase or by the pressure increase recorded on extruding a predetermined amount of pigment or filler.
• the known method described above has the drawbacks that it requires a suitable extruder, dilution with virgin polymer is necessary, and execution of the test takes quite an appreciable time, which can be estimated as at least half an hour, plus the time required for cleaning the extruder.
• the subject-matter of the present invention is an apparatus for carrying out the pressure filter test and the associated test procedure, having the characteristics referred to specifically in the Claims given later.
• the apparatus of the invention offers the advantage of being able to work directly on the extruded material or during mixing by a process extruder without the need to carry out any dilution with virgin polymeric material, or of using an additional dedicated extruder. It is moreover compatible with essentially any type of extruder used conventionally for mixing a polymer matrix with a filler or pigment. Furthermore, both the material that passed through the test filter and the material used for "washing" the apparatus between successive measurements can be returned to the production cycle, with an obvious economic benefit.
• the apparatus of the invention offers the further advantage of carrying out a single measurement in a very short time - of the order of 15 minutes - so that said measurement can be repeated often and it permits systematic quality control according to automated procedures .
• the apparatus of the invention is also able to conduct the test on material while it is being mixed in the extruder, it means that process control can be performed substantially in real time. Consequently, any defects can be corrected as soon as they occur, avoiding the production of batches of material which must then be scrapped after testing for verification of quality.
• Fig. 1 is a front view of apparatus of the invention, mounted on an extruder,
• Fig. 2 is a sectional view along line II-II in Fig. 1, and
• Fig. 3 is a schematic representation of various possible sites for installation of the apparatus of the invention on an extruder.
• An apparatus 10 for carrying out the pressure filter test is mounted (Figs. 1 and 2) downstream of the head 12 of an extruder 14 intended for producing a material formed by mixing a filler and/or a pigment with a polymer matrix.
• a branch pipe 16 which starts from an outlet pipe 18 for the extruded material and ends at the mouth 20 of a measuring pipe 22 of apparatus 10.
• the measuring pipe 22 comprises a first section 24 provided inside the body of a pump 26 and a second section 28 provided inside a coupling 30 that supports a filter 32 placed across the pipe 22.
• Pump 26 is of a type that can guarantee a constant delivery, for example a gear pump.
• Heat generating means - for example of the type with an electric resistor 34 - are provided round part of the body of the pump 26 and the coupling 30 that supports the filter 32.
• a manometer 36 is mounted within coupling 30 to permit detection of the pressure drop through the filter 32.
• the pressure filter test is carried out on line during normal operation of extruder 14, which continues to deliver mixed material through the head 38 of outlet pipe 18.
• By operation of the pump 26, a fraction of the extruded material is directed into the branch pipe 16 of head 12 and flows from there into the measuring pipe 22, from where it passes through the filter 32.
• the heat generated by electric resistor 34 maintains the extruded material in the fluid state, and therefore it can flow freely.
• Fig. 3 shows various possible sites for installation of the apparatus of the invention on the extruder 14.
• the installation site of the apparatus indicate d by reference number 10a corresponds to the site at the head 12 of extruder 14, already described in detail with reference to Figs. 1 and 2.
• the sites of installation of the apparatuses indicated by reference numbers 10b, 10c, 1Od and 1Oe are respective portions of the side wall of extruder 14. It should be pointed out that although the simultaneous installation of several apparatuses 1Oa-IOe on the same extruder is not excluded, the various installation sites shown in Fig. 3 are typically alternative, and can possibly be used at different times .
• the means for directing a fraction of material into the measuring pipe 22 comprise the mouth 20 of the latter, arranged as an extension of a respective opening 40 in the side wall of the extruder 14.
• the remaining components of the apparatuses lOb-lOe, and the respective operating modes, correspond to those of apparatus 10a. It is only necessary to point out that the apparatuses lOb-lOe do not carry out measurement on the final extruded material, but on the material at different respective stages of mixing inside the extruder 14, thus permitting process control to be performed substantially in real time. Accordingly, it is possible to correct any defects as soon as they appear, avoiding, or at least greatly reducing, the production of reject batches of material.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Health & Medical Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=36607504

Family Applications (1)

Country Status (2)

Cited By (3)

Citations (4)

• 2005
  • 2005-03-31 IT IT000211A patent/ITTO20050211A1/it unknown
• 2006
  • 2006-03-20 WO PCT/EP2006/060881 patent/WO2006103184A1/en not_active Ceased

Patent Citations (4)

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