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AU644086B2 - Process for the preparation of a colored plastic molding material - Google Patents

Process for the preparation of a colored plastic molding material Download PDF

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Publication number
AU644086B2
AU644086B2 AU58870/90A AU5887090A AU644086B2 AU 644086 B2 AU644086 B2 AU 644086B2 AU 58870/90 A AU58870/90 A AU 58870/90A AU 5887090 A AU5887090 A AU 5887090A AU 644086 B2 AU644086 B2 AU 644086B2
Authority
AU
Australia
Prior art keywords
molding material
monitoring
light source
pigment
material particles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
AU58870/90A
Other versions
AU5887090A (en
Inventor
Detlef Klaus Busch
Horst Grohmann
Harald Kutzner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hoechst AG
Original Assignee
Hoechst AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hoechst AG filed Critical Hoechst AG
Publication of AU5887090A publication Critical patent/AU5887090A/en
Application granted granted Critical
Publication of AU644086B2 publication Critical patent/AU644086B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20Measuring; Control or regulation
    • B01F35/21Measuring
    • B01F35/2131Colour or luminescence
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20Measuring; Control or regulation
    • B01F35/22Control or regulation
    • B01F35/2201Control or regulation characterised by the type of control technique used
    • B01F35/2202Controlling the mixing process by feed-back, i.e. a measured parameter of the mixture is measured, compared with the set-value and the feed values are corrected
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/80Forming a predetermined ratio of the substances to be mixed
    • B01F35/82Forming a predetermined ratio of the substances to be mixed by adding a material to be mixed to a mixture in response to a detected feature, e.g. density, radioactivity, consumed power or colour
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01FMIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/60Mixing solids with solids

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Spectrometry And Color Measurement (AREA)
  • Dental Preparations (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)

Abstract

In the case of the present method, the colour of the material is continuously measured and the measuring signals are used indirectly for controlling the mixing ratio of plastic and pigment. For this purpose, samples are continuously taken from the material flow downstream of the mixing system (1) and this material is taken closely packed through the measuring device (6) past the measuring window. The surface of the material particles is illuminated by the measuring window and the reflected light is captured by sensors, which allow the colours green, blue and red to be measured. The processing of the measuring signals to form control signals for the metering systems in the mixing system takes place by computer. The method is suitable in particular for making coloured plastic granules. <IMAGE>

Description

j 64408C6 FormF COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION
(ORIGINAL)
Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant Address of Applicant: *Actual Inventor Address for Service HOECHST AKTIENGESELLSCHAFT 50 Bruningstrasse, D-6230 Frankfurt/Main of Germany 80, Federal Republic DETLEF KLAUS BUSCH, HORST GROHMANN, HARALD KUTZNER WATERMARK PATENT TRADEMARK ATTORNEYS.
LOCKED BAG NO. 5, HAWTHORN, VICTORIA 3122, AUSTRALIA Complete Specification for the invention entitled: PROCESS FOR THE PREPARATION OF A COLORED PLASTIC MOLDING MATERIAL The following statement is a fuil description of this invention, including the best method of performing it known to us HOECHST AKTIENGESELLSCHAFT HOE 89/F 224 Dr.DA/sch Description Process for the preparation of a colored plastic molding material The invention relates to a process for the preparation of a colored plastic molding material, in which the color of the molding material is continuously monitored atti the test signals are used indirectly to control the mixing ratio of plastic and color pigment.
In the known process for the preparation of colored plastic granules, a mixture of polymer and pigment, the *latter usually in concentrate form, and optionally .me.auxiliaries, is introduced into a granulator and pro- *cessed into granules. Samples of these granules are taken and molded into test pieces, the shade of which is assessed visually or colorimetrically. If appropriate, the mixing ratio of polymer to pigment is then changed.
Changes are made to this ratio until the shade of the granules coincides with the specified shade.
Owing to the time consumed in preparing and assessing the test pieces, discrepancies such as those which are caused, for example, by differences between the batches of pigment, can only be detected after a lengthy period.
As a consequence, the proportion of substandard product can amount to several percent. In particular, the production of end products for which individual components of mess,,identical shade are made from granules from different production runs or different production units, requires continuous tracking of the shade during polymer pigmentation to ensure that the variants of actual shade from the control approaches zero. To achieve this, the batches of granules miust be homogenized in a costly additional process step.
2 The object is therefore to determine the shade of plastic molding materials, in particular plastic granules, continuously during their production and to use the results as rapidly as possible to control the metering of polymer and pigment.
It has been found that a continuous monitoring of the shade of the molding material is possible if the molding material particles are fed past the monitoring apparatus in a suitable manner.
The present invention herefore provides a process for the continuous monitoring of the shade of a colored surface dry powdered or granular plastic molding material by illuminating the surface of the molding material by means of a light source and monitoring the colors green, blue and red in the light reflected from the surface of the molding material particles, wherein the molding material particles which are close-packed in a graduated tube are fed at a minimum velocity of 1 cm/sec through monitoring apparatus past a measuring window.
Preferably the molding material is admixed with at least one pigment; samples of the molding material are continuously removed for monitoring in the monitoring apparatus; and the light source is a constant color temperature light source.
The invention also provides an apparatus for the continuous monitoring 20 of the shade of a colored surface dry powdered or granular plastic molding V. material which comprises a light source for illuminating the surface of the molding material, means for passing the molding material particles closepacked in a graduated tube at a minimum velocity of 1 cm/sec through monitoring apparatus past a measuring window, and monitor means for monitoring the colors green, blue and red in the light reflected from the surface of the molding material particles.
Preferably again the molding material is admixed with at !east one pigment; the apparatus includes means for continuously removing samples of the 30 molding material for monitoring in the monitoring apparatus; and the light source is a constant color temperature light source.
Finally, in a particularly preferred form the invention provides the apparatus for the continuous monitoring of the shade of a colored plastic molding material, this apparatus comprising a feed hopper a graduated tube (62) connected thereto in which a glass measuring window (63) has been set, a light source (64) outside the tube (62) and in front of the measuring window and a sensor bank Light source (64) 0 o *o* -3and sensor bank (66) can be arranged next to each other.
Preferably they are combined by using an optical fiber bundle (67) to introduce light and to lead off the reflected light. In this case, light source (64) and sensor bank (66) are located in a separate housing.
In the process according to the invention, samples are taken continuously from the stream of dry colored material downstream of the mixer. The molding material can have been obtained by various processes, the essential points being that it must be dry on the surface and that no water condensation can form during monitoring.
Samples can be taken completely continuously by diverting a small portion of the material flow, or else they can be or ~taken continuously at time intervals. Preferably samples 15 are taken from the material flow at regular time inter- 4• vals, for example by suction. The samples of material are passed from the sampling device to the feed hopper of the 0 .monitoring apparatus.
The monitoring apparatus consists of a tube of round or square cross-section in whose wall a window sealed with a glass plate has been fitted. At one end, the tube has the form of a feed hopper and at the other end it is connected to an apparatus which uniformly empties the tube and simultaneously forms a barrier to possible vapors or e 25 gases emanating from the main stream of the molding material. Preferably a star feeder is used.
In front of the measuring window a light source is oeoI• Sarranged having a virtually constant color temperature, for example a halogen lamp. This illuminates the molding material particles which are located in the tube. The light reflected from the particles is then received by three sensors which are responsive to the colors gzeen, blue or red.
The harmonized functioning of the feed hopper and the emptying apparatus ensure that the graduated tube is 4 always kept full and the molding material particles are always close-packed. This is essential for evaluating the test signals from the tranducers. Current averaging over the individual test signals in a measuring and control unit averages out the variations in the mobile molding material surface (silhouetting and i-zerstices). This "current average" is compared with a reference mean which has been obtained as a reference value by monitoring and storing of a reference sample. The difference between the desired value and the actual value is used to control the metering apparatuses of the mixer.
The Figures show the process according to the invention o. as a flow diagram and the monitoring apparatus employed for the process in the preferred use with plastic *15 granules. These granules have a round or rectangular **cross-section, a diameter of 1 to 5 mm and a particle length of 0.5 to 5 mm.
In accordance with Figure 1 a constant stream of drycolored granules flows from the granulator The sampling apparatus regularly takes samples via line and passes them through line into the monitoring apparatus from which they are withdrawn by the emptying apparatus through the line and are again introduced into the granule stream via line The signals obtained from the monitoring apparatus are processed in the computer (10) to give control inputs and are used to actuate the metering control apparatus (11).
The contro) signals coming from the control apparatus (11) are passed via cables (12) and (13) to the granulator Figure 2 shows a preferred form of a monitoring apparatus. The sampling apparatus a suction fan and the emptying apparatus a star feeder, are mounted directly on the monitoring apparatus The lines and are thus eliminated and line enters directly into the feed hopper (61) of the monitoring apparatus 5 The graduated tube in which the glass measuring window (63) is set, is connected to the feed hopper Through this measuring window a light source (64) illuminates, via the optical fiber bundle the surface of the granules (65) as they are fed past. The reflected light is captured by the sensor bank (66) and the green, blue and red color components are supplied separately in the form of electrical signals to the computer not shown.
The correct color monitoring of the granules is highly dependent on the velocity at which the granules flow past the measuring window. A minimum velocity of 1 cm/sec has •e been established. The color temperature of the halogen lamp is kept constant using an appropriate brightness 15 control which tracks the lamp voltage (in the present *0 case about The output voltage range of each of the three color sensors is 0...10V. The signals are digitalized in an A/D-converter (12 bit), smoothed by averaging and fvd to the granule brightness computation..
Thus, 4 values are available for determining the color; 3 measured values from the selective color frequency monitoring and the computed brightness. These are compared in a computer with the stored values of the desired granule color and made ready for further processing.
0 High resolution in the range of the desired value is necessary to detect even the smallest variances of the actual value. This is achieved using signal spreading.
4 Normally, the voltage signal is at 100 mV. The 0 control input thus obtained for adjusting the color is fed into an appropriate control apparatus which again adjusts the control signals for the installed metering apparatu s. These correspond to the values which are customary in measurement technology, 0/2...1OV or 0/4...20mA.
Controlling the metering ratio of polymer to coloring polymer-pigment mixture(s) gives a constant product -6quality within the product stream, this being based on the constant and reproducible measured values from color monitoring of the continuous sample stream.
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Claims (8)

1. A process for the continuous monitoring of the shade of a colored surface dry powdered or granular plastic molding material by illuminating the surface of the molding material by means of a light source and monitoring the colors green, blue and red in the light reflected from the surface of the molding material particles, wherein the molding material particles which are close-packed in a graduated tube are fed at a minimum velocity of 1 cm/sec through monitoring apparatus past a measuring window.
2. A process as claimed in Claim 1, in which the molding material is admixed with at least one pigment.
3. A process as claimed in Claim 1 or 2, in which samples of the molding material are continuously removed for monitoring in the monitoring apparatus.
4. A process as claimed in Claims 1, 2 or 3, in which the light source is a constant color temperature light source. S
5. Apparatus for the continuous monitoring of the shade of a colored surface o. dry powdered or granular plastic molding material which comprises a light source for illuminating the surface of the molding material, means for passing the molding material particles close-packed in a graduated tube at a minimum velocity of 1 cm/sec through monitoring apparatus past a measuring window, and monitor means for monitoring the colors green, blue and red in the light reflected from the surface of the molding material particles.
6. Apparatus as claimed in Claim 5, in which the molding material is admixed with at least one pigment. e S•• 8
7. Apparatus as claimed in Claim 5 or 6, which includes means for continuously removing samples of the molding material for monitoring in the monitoring apparatus.
8. Apparatus as claimed in Claims 5, 6 or 7, in which the light source is a constant color temperature light source. DATED THIS 9TH DAY OF SEPTEMBER, 1993 HOECHST AKTIENGESELLSCHAFT WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA DBM:IAS:BB DOC 30 AU5887090.WPC S
AU58870/90A 1989-07-12 1990-07-11 Process for the preparation of a colored plastic molding material Ceased AU644086B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3922902A DE3922902A1 (en) 1989-07-12 1989-07-12 METHOD FOR PRODUCING A COLORED PLASTIC MOLD
DE3922902 1989-07-12

Publications (2)

Publication Number Publication Date
AU5887090A AU5887090A (en) 1991-01-17
AU644086B2 true AU644086B2 (en) 1993-12-02

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ID=6384806

Family Applications (1)

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AU58870/90A Ceased AU644086B2 (en) 1989-07-12 1990-07-11 Process for the preparation of a colored plastic molding material

Country Status (8)

Country Link
EP (1) EP0407927B1 (en)
JP (1) JPH0345304A (en)
AT (1) ATE107190T1 (en)
AU (1) AU644086B2 (en)
CA (1) CA2020947A1 (en)
DE (2) DE3922902A1 (en)
ES (1) ES2056308T3 (en)
ZA (1) ZA905423B (en)

Families Citing this family (15)

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Publication number Priority date Publication date Assignee Title
ES2140510T3 (en) * 1993-10-04 2000-03-01 Gen Electric SYSTEM TO CONTROL THE COLOR OF ONE OR MULTIPLE POLYMERS IN COMPOSITION USING COLOR MEASUREMENTS DURING THEIR TREATMENT.
DE19626785A1 (en) * 1996-07-03 1998-01-08 Basf Ag Process and device for the continuous color measurement of plastic molding compounds
BR9801134A (en) 1998-03-26 2006-11-14 Renner Herrmann Sa apparatus and process for the continuous preparation of a fluid with automatic adjustment of its properties
US6469789B1 (en) 2000-08-22 2002-10-22 General Electric Company On-line color measurement system for cooled product
DE10219034B4 (en) * 2002-04-29 2004-04-08 Bayer Ag Method and device for determining the color of plastic granules
WO2009040291A1 (en) * 2007-09-21 2009-04-02 Basf Se Method and apparatus for measuring colour properties of plastic granules
DE102008013170A1 (en) * 2008-03-07 2009-09-10 Wobben, Aloys A method of adjusting a mixing ratio of two or more components
DE102011113543A1 (en) * 2011-09-15 2013-03-21 Klöckner Pentaplast GmbH & Co. KG Colored polymeric moldings, process and apparatus for producing the moldings
DK3843966T3 (en) * 2018-08-29 2023-01-09 Erema Eng Recycling Maschinen & Anlagen Gmbh METHOD AND APPARATUS FOR THE PROCESSING, PROCESSING AND/OR RECYCLING OF THERMOPLASTIC PLASTIC MATERIALS
WO2020193383A1 (en) * 2019-03-26 2020-10-01 Covestro Intellectual Property Gmbh & Co. Kg Method for determining a color value of a transparent bulk material
DE102019217090A1 (en) * 2019-11-06 2021-05-06 LIEB TGA GmbH Mixing device, casting device and method for operating a mixing device
CN113546552A (en) * 2021-07-27 2021-10-26 北京住总集团有限责任公司 A mud mixing device
FR3126321A1 (en) * 2021-09-01 2023-03-03 L'Air Liquide Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude CONTINUOUS MIXING DEVICE AND ASSOCIATED METHOD
FR3127281B1 (en) 2021-09-23 2023-08-25 Exel Ind Shade measuring device for a fluid distribution system
CN115382461B (en) * 2022-10-31 2023-05-12 东营市宝泽能源科技有限公司 Iron ion stabilizer production device and method with proportioning adjustment function

Citations (1)

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Publication number Priority date Publication date Assignee Title
US4684488A (en) * 1985-02-14 1987-08-04 Werner & Pfleiderer Method and apparatus for controlled supply of color concentrates into an extruder to obtain a plastic product of desired coloration

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DE2133797A1 (en) * 1971-07-07 1973-01-25 Hoechst Ag Polymer discolouration measurement - during flow by optical absorption to detect quality defects
US4403866A (en) * 1982-05-07 1983-09-13 E. I. Du Pont De Nemours And Company Process for making paints
US4799799A (en) * 1985-02-06 1989-01-24 The United States Of America As Represented By The Secretary Of The Interior Determining inert content in coal dust/rock dust mixture
JP2567601B2 (en) * 1987-03-27 1996-12-25 サンスター技研 株式会社 Method of inspecting coating state of coating agent
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Patent Citations (1)

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US4684488A (en) * 1985-02-14 1987-08-04 Werner & Pfleiderer Method and apparatus for controlled supply of color concentrates into an extruder to obtain a plastic product of desired coloration

Also Published As

Publication number Publication date
ZA905423B (en) 1991-04-24
ATE107190T1 (en) 1994-07-15
EP0407927A3 (en) 1992-07-22
JPH0345304A (en) 1991-02-26
EP0407927B1 (en) 1994-06-15
DE59006110D1 (en) 1994-07-21
CA2020947A1 (en) 1991-01-13
AU5887090A (en) 1991-01-17
EP0407927A2 (en) 1991-01-16
DE3922902A1 (en) 1991-01-17
ES2056308T3 (en) 1994-10-01

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