WO2017136910A1 - Équipement de détection optique de diffusion de lumière laser aux petits angles (lalls) en ligne, utilisation de ce dernier et procédé de surveillance morphologique en temps réel de systèmes polyphasiques - Google Patents

Équipement de détection optique de diffusion de lumière laser aux petits angles (lalls) en ligne, utilisation de ce dernier et procédé de surveillance morphologique en temps réel de systèmes polyphasiques Download PDF

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WO2017136910A1
WO2017136910A1 PCT/BR2017/000014 BR2017000014W WO2017136910A1 WO 2017136910 A1 WO2017136910 A1 WO 2017136910A1 BR 2017000014 W BR2017000014 W BR 2017000014W WO 2017136910 A1 WO2017136910 A1 WO 2017136910A1
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laser light
intensity
plate
detector
scattering
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PCT/BR2017/000014
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English (en)
Portuguese (pt)
Inventor
Sebastião Viceente Junior CANEVAROLO
Thiago Manha GASPARINI
Lidiane Cristina COSTA
Carlos Alberto CÁCERES COAQUIRA
Juliano CONTER DAMIANI
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Fundação Universidade Federal De São Carlos
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Publication of WO2017136910A1 publication Critical patent/WO2017136910A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
    • G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons

Definitions

  • the present invention belongs to the field of low angle laser light scattering (LALLS) optical detection equipment, more specifically, optical detection equipment to be used in m ' Une mode, i.e. tracking characteristics material morphology along the flow line of a given process, more particularly that of non-invasive, real-time polyphase system extrusion.
  • LALLS low angle laser light scattering
  • the light can suffer four basic phenomena: transmission, reflection, absorption and refraction.
  • transmission the incident light propagates through the material without changing its direction, but its polarization state may change.
  • reflection the incident light is absorbed and reissued by the surface atoms of the material.
  • absorption at least part of the radiant energy is converted into heat and dissipated by the material.
  • the refraction is characterized by the optical path deviation of the incident light, due to the polarization of the electronic cloud of the constituent atoms of the material, with the interaction of the light's electric field.
  • Mie's theory is one of the most widely used models for calculating the intensity of light scattered by spherical particles whose diameters are of the same order or greater than the wavelength of the light used.
  • the model idealizes the particles as spherical, isotropic, non-magnetic and smooth surface, dispersed in a non-absorbent medium by Huist, H. C. Light scattering by small particles. New York: Dover, 128-129, 1981].
  • particles are finite objects that contain distributed a number of scattering centers that is proportional to their volume, ie their size. When these particles scatter the light, the scattering centers are sufficiently separated so that interference may occur between the rays emitted from different regions of the particle (see Jenkins, ,; F. White, Fundamentals of Optics HE. 3a. Ed. New York: McGraw-Hill, 450, 1957). Thus, particles of different diameters have different intensity distribution or spreading profiles, which allows their identification, as shown in Figure 1 attached to this report. [0008] By the Mie model, the scattered light intensity / s for a spherical wall is a function of the relative refractive index (m), the number (x) and the scattering angle ⁇ & as shown in Equation 1.
  • k is the initial intensity of the light beam
  • k is the wave number, equal to 2 ⁇ / ⁇
  • r is the distance between the spreading center (sample) and the detector.
  • the refractive index is given by:
  • n p is the refractive index of the material that makes up the particle
  • en m is the refractive index of the material that makes up the matrix
  • the ratio of particle circumference to wavelength in the middle (x) is defined by:
  • the refractive index is a feature of the material of paramount importance to the Mie light scattering model. It is a complex number and as such has a real component, associated with light bending, and a component. imaginary, related to the absorptivity of the material. For non-light absorbing particles, the imaginary component may be considered null.
  • the Mie Theory is simplified to Fraunhoffer diffraction concept.
  • the phenomenon is called diffraction, and is characterized by the deviation of the lu as it passes tangentially to the surface of the dispersed particles. This generates interference from the waves and is revealed at a certain distance from the place where it occurred, through maximums and minimums of light intensity.
  • Patent documents aiming at online characterization generally deal with methods that involve the segregation of a process stream and analysis of its morphological characteristics by any method, which differs from the present process, which inline analyzes the polymer stream in real time extrusion of its production, without effecting any process stream segregation.
  • Some publications of the type include US publications US 6618144, US 6653150 and US published application US 2009030631 1.
  • Prototype 1 was created in 2005 from Juliano Conter Damiani's master's thesis "Development of a ⁇ LALLS low-angle laser light scattering detector operating in real time in extrusion", the second Prototype I! in 2007 in Lid ⁇ ane C's master thesis. Likes “Use of in-i LALLS in the extrusion of biphasic polymer systems” and the last IH Prototype, in 2015 in Thiago Manha Gasparini's master thesis " Improvement of a scatter detector low-angle laser light (LALLS in-iine) for real-time monitoring of the extrusion process ".
  • Transparent windows the slit-like matrix was provided with two transparent borosilicate glass windows that surrounded the molten flow. Its shape was of two large cylindrical biocosms of 20mrn in diameter and 24mm in height. Its locking and sealing system involved a double closure system formed by two rings. The first sealed the melt flow between the glass window and the metal matrix and the second kept the window fixed in place, sustaining the pressure of the molten flow. Such a design smashed the glass cylinder so that to prevent it from breaking, it had to be loosely tightened, limiting its use only to low pressures in the matrix slot of up to 30Dpsi. This model remained constant in Prototype IS, but was radically altered in Prototype III.
  • the 'rumination source used was a "red laser pointer produced with a very low cost, low power solid semiconductor ( ⁇ 7p), undefined wavelength ranging from 610 - 690nm and unstable behavior
  • this radiation source has been replaced by a commercial monochrome, non-polarized and collimated helium / neon red laser source, elies Gr ⁇ ot, model 05-LHP-401, with a reactive power of 57.3pW and wavelength 632.8 nm This model remained constant in Prototype lii.
  • the phototransistors were encased in a metal tube (tapered or not), with an approximate 30 ° angle painted internally matte black, to minimize light reflection inside. Said tube or cone is cooled by a copper tube welded to it by which running water circulates, when said cone is in contact with hot surface, thus can be subjected to extrusion temperatures in the order of 240 ° C, without degrading the components. electronics pinned to it. This component remained constant without changes in the three prototypes. For the characterization of finished products, analyzed close to the ambient temperature is not The presence of the cooling system is required, simplifying assembly.
  • Photoelement signal leveling system In the inner wall of the Prototype I darkroom four red LEDs were placed, arranged at 90 °, with wavelength close to the laser light source and variable and controlled intensity, for individual leveling. of each of the 64 phototransistors that constituted the detection system. Different levels of light intensity were produced through the manual control of the LED's supply current. Such a leveling system is not efficient, since besides being manually operated it does not produce a homogeneous and constant light intensity over all phototransistors, making leveling difficult. This model remained constant in Prototype .11, but was radically altered in Prototype lil with the introduction of the Homogeneous Leveling Illumination Plate and its mathematical treatment to be discussed below, constituting one of the claims of the present application.
  • CdS cadmium sulfide
  • LDR Hd t resistor-dependent photocell-type photoelements for the detection of scattered light intensity.
  • Prototype II These sensors have been replaced by phototransistors that respond much faster (milliseconds), are more sensitive, and have more predictable behavior. All are read simultaneously. Their responses to light intensity have been normalized, said leveled (this procedure will be described later in this report) so that the signals from each phototransistor can be compared quantitatively with each other. This makes the LALLS detection system quantitative as presented. in the present application, which distinguishes it from earlier prototypes that were only qualitative.
  • Detector plate Es ⁇ a is composed of photo elements arranged in a nine-ray configuration, 33.75 ° out of phase, with seven to ten phototransistors in each radius and one in the center.
  • the central photoelement has the function of capturing and quantifying the intensity of transmitted and non-scattered radiation and the other photoelements have the function of quantitatively capturing the intensity of transmitted and scattered radiation.
  • Such arrangement of the photo elements is due to the assumption that there is scatter symmetry in each of the four quadrants. This means that after bending all the signals to each of the four quadrants it is mathematically that the radii are only 11, 25 ° (360/32) apart.
  • the central photoelement has the function of capturing and quantifying transmitted and non-scattered radiation. This ability initially allows, before making measurements, to align the laser light beam and after, during experimental measurements, determine the turbidity of the system, including the distribution of residence time of the extruder, among other variables.
  • a 10mm metal cylinder. of length and inner diameter equal to the outer diameter of the phototransistor (in the case of 3 mm prototype IH) has one end fixed over the phototransistor and the other remaining open. Within this metal cylinder is inserted a double physical barrier acting to pre-define the penetration area of the laser beam and significantly reduce the light intensity that reaches it.
  • the first barrier closest to the photoefement, was a thin metal foil with a small central hole, of the order of 0.5 mm in diameter (pine), whose function is to allow the centralization of the laser beam.
  • the second barrier, placed on this metal sheet is composed of a layer of black plasticine that strongly absorbs the radiation reducing its intensity a. levels that can be quantified by the central phototransistor while generating minimal scattering behind the incident laser beam, said scattering by reflection.
  • the metal cylinder has its length aligned with the laser light beam, so that the beam can enter it through the open end, pass through the plasticine layer, the hole of the metal plate and finally reach the central region of the phototransistor for its use. quantification.
  • Exiosorous tube (not shown) In Prototypes I and II the minimum scattering angle that can be measured is 3.25 °, the which corresponds to a distance between sample and plate of approximately 18cm. This allows quantifying small structures. If there is an intention to quantify larger structures then it is necessary to reduce the smallest measurable angle.
  • This can be implemented in the present application by the addition of a flange-shaped extension tube to be inserted between the darkroom and the demarcator plate. This tube increases the distance between the sample and the slide plate, thus reducing the spreading angle to be captured. In this way larger structures can be analyzed. For example, if the intention is to measure scattering angles of the order of 0.25 ° the length of this flange should reach approximately 2.5 m.
  • Signal Conversion and Amplification Box This box packs the set of electronic circuits that allow quantifying the variation of the photoelectric resistance.
  • the housing is electrostatically shielded to reduce system noise.
  • this box had only eight circuits, allowing the simultaneous reading of the eight LDR cells present in only one radius at a time.
  • This box was reformulated in Prototype -III, because the photocells were replaced by phototransistors (as an example in this application were used NPN type L-32P3C) requiring the change of electronic circuits. 91 circuits were also built so that the reading of all phototransistors can be read simultaneously.
  • Homogeneous illumination plate for leveling and normalization of phototransistor signals This plate was developed in Prototype III and is part of the claims of the present application. It consists of a light source made up of a row of stepped intensity red LEDs fixed to the edge of a homogeneous light plate. The light produced in the LED's propagates through the thickness of the plate and is scattered to one of its faces, said radiant face, through a set of optical filters that compose the said plate. The light radiation emerging from this plate is homogeneous and of constant intensity throughout the radiant face. Such radiant intensity reaches all phototransistors also homogeneously and constantly allowing the leveling of all of them.
  • said plate is inserted into a slit-shaped window on the side of the darkroom, allowing the positioning of said plate immediately over the phototransistors and with its radiant fac facing said phototransistors.
  • Such arrangement allows to obtain the response curve of each phototransisor to the variation of luminous intensity incident on each phototransis ⁇ or and therefore to carry out quantitative analyzes of the scattered light intensity, object of this patent application.
  • Automated Phototransistor Leveling System An automatic control and its mathematical treatment, managed by software, performs the signal-leveling of each of the 90 phototransistors.
  • the software sends a command to the AD / DA board which in turn sends a current level to the leveling board LEDs.
  • This produces a light radiation on the homogeneous lighting plate of known intensity level between a minimum and a maximum value, previously set by the equipment operator.
  • the signal / response collection of each phototransistor is made.
  • the level of luminous intensity of said homogeneous illumination plate is then automatically increased by obtaining a new measurement of the phototransistor response.
  • Analog / Digital Conversion Board AD / D ⁇ In Prototypes i and Prototype II to coil the voltage of each photocell and transform it from analog to digital signal, an external interface KIT 118 12B! T from Gual ⁇ ty 63 Kits is used. , which picks, transforms and sends it to the computer through the printer output. This interface has only 8 channels, requiring eight measurements under the same conditions to quantify the detector's 64 photocells. This makes the test difficult when the measurement is made in the transient state, since the test must be repeated 9 times and each time the 7 single-radius photocells are measured.
  • NI USB-6225 80 analog input and 2 output channels
  • Ni USB-6218 32 analog input and 2 output channels
  • 80 acquisition channels and 1 NI USB-6225 card output channel and 1 USB-6218 I card acquisition channels were used. In this way all 91 signals are measured simultaneously and used for further analysis.
  • Laser beam intensity control Depending on the physicochemical characteristics of the sample to be analyzed (thickness, second phase concentration, orientation level, etc.) it is necessary to adjust the intensity of the laser beam by increasing it. o or decreasing it. In order for the phototransistor response to be in its measured range it is necessary that the intensity be between a minimum that is not affected by noise and a maximum that does not saturate the phototransistor response. In the present application this need has been addressed by adding a polarizing filter to the optical path of the incident beam positioned just in front of the laser light source. This circular filter can be rotated up to 100 degrees by hand or automatically.
  • this polarizing filter As the laser beam is polarized, the interposition of this polarizing filter on its optical path affects the intensity of the polarizer rotation from a minimum effect position when the two polarization axes (laser and filter) are aligned to one another. maximum reduction effect when the two axes are crossed. Thus it is possible to adjust the intensity of the laser beam reaching the sample by rotating the polarizing filter and observing the result of the on-screen 3D Scattering Curve (presented and discussed later in this report).
  • Photoefemen ⁇ os The 64 light intensity sensors initially of the LDR type were replaced by 91 phototransistors that present much faster response (milliseconds), are more sensitive, and have more predictable behavior. All are operated simultaneously. Their responses to light intensity have been normalized, leveled days, so that the signals can be compared directly. The respective electronic circuits have been modified to operate such phototransistors.
  • Homogeneous Illumination Plate for leveling and normalizing phototransistor signals In order for the response of each of the 90 phototransistors to the same light intensity to be equal, a new form of illumination is revealed through the use of a plate that radiates light homogeneous in the whole area covered by the phototransistors and with stable, variable and discrete intensity automatically controlled by software. Such a plate is inserted into the darkroom through a lateral slit so as to position it with its radiant face directly over the set of all phototransistors.
  • Automated Phototransistor Leveling System The response leveling of each of the 90 phototransistors is a mathematical treatment done automatically by adjusting an exponential response curve of each phototransistor to the illumination generated by the homogeneous lighting plate, producing a pair of coefficients. for each phototransistor. Such leveling should always be done before obtaining quantitative measurements of the sample to be analyzed.
  • Transparent windows The double-locking cylindrical type windows disclosed in Prototypes I and li have been replaced by small windows in the form of discs of clear glass which may be borosilicate, sapphire or other transparent material, 1'Omm in diameter. and 1 mm thick, seated on a recess in the slot-like matrix and glued with adhesive.
  • An example of adhesive may be Araldite type.
  • heat treated borosilicate-based glass should be used to relax the frozen internal stress level. Such heat treatment can be done in mafia at a temperature of 500 to 520 ° C for a time period of 5 to 24 hours.
  • Extension Tube (not shown) When the intention is to quantify larger structures, the smallest measurable angle should be reduced by inserting a flange-shaped extension tube between the darkroom and the detector plate. This tube increases the distance between the sample and the detector lacquer, thus reducing the scattering angle to be captured. In this way larger structures can be analyzed. For example, to measure scattering angles of the order of 0.25 ° the length of the flange. should reach approximately 2.5 m. To avoid weight gain this pipe should be made of lightweight material, eg plastic pipe used in plumbing in construction.
  • ⁇ Compactor Program This program is responsible for all system control including: laser beam alignment, automated leveling of the 90 phototransistors, pickup of these same signals plus the central phototransistor signal, data handling, screen display. of various graphs particularly a 3D graph of 3D Scatter Curves and file recording.
  • the use of the equipment disclosed herein allows the sample production system (melt flow, polymeric film, textile fiber, effect) to be automatically controlled via in-line feedback, produced and provided by the in-line LALLS equipment disclosed in this invention.
  • in-line measurement of morphological properties of a polymeric polyphase system yields results that can be analyzed when the material is still in the molten state (or intermediate form) or already in the solid state (in product form). (ie films, fibers, flasks, bottles, etc.) which according to the invention comprises installing and operating LALLS optical detector equipment in the following situations:
  • the LALLS optical detector equipment is installed on one side of a transparent window slotted matrix, fixed at the outlet of said one.
  • extruder means a non-polarized collimated monochromatic laser light source fixed by a support and alignment structure; and on the opposite side of the slit-matrix windows, a darkroom (conical or not) fitted with a cooling system, detector plate containing at least one photoelement, electronic signal conversion and amplification circuits, and homogeneous lighting plate with stepped control. intensity for leveling the photoelements, said plate being inserted into a slit of said darkroom.
  • the sample is in the form of finished product and may be films, fibers, vials, bottles, and the like.
  • LALLS optical detector equipment is installed enclosing the finished product on one side with a non-polarized collimated monochromatic laser light source fixed by a support and alignment structure; and on the opposite side of said finished product, a darkroom (conical or not), a detector plate containing at least one photo-element, electronic signal conversion and amplification circuitry and a homogeneous photoelectric light-intensity leveling control plate, said piaca being inserted into a slit of said darkroom.
  • the uses of the present optical detector equipment for real time analysis of polyphase systems include:
  • the method for real-time morphological monitoring of molten state polyphase systems comprises the following steps:
  • the method for morphological monitoring in real time! of thin-wall finished products (films, fibers, flasks, etc.) directly on the production line, made with polyphase systems comprises the following steps:
  • the invention provides a laser-based LAUS optical detector device comprising a darkroom provided with a detector plate containing photosensitive elements (phototransistors), the response of said phototransistors being leveled through a sink inserted into said one. darkroom and positioned directly over the phototransistor assembly, such a detector device It can be adapted from one row and another of the slit-like die of an extruder or a thin-wall finished product for respectively the in-line measurement of the properties of polyphase systems during the course of production of the polymeric system in extrusion or already in production. finished product form.
  • Equipment of the invention for in-line low angle laser light scattering (LALLS) optical detection including laser alignment system (70), laser light source (71), detector plate (10) and camera (20), cooling system (30), tubular connection frame (60, 62), signal conversion box (80), A / D conversion board (90) and computer (95) for running monitoring software and controie comprises:
  • center photoelement (11) being directed, with the aid of the laser alignment system (70), the transmitted and non-scattered laser light beam, additionally said center photoelement (11) being intended to quantify the intensity of the transmitted beam and not scattered across the sample (51), measuring the turbidity of the medium; b) in said darkroom (20), side opening or slot (41) for insertion of a transparent plate (40) of homogeneous illumination for leveling the response of the photo elements (12), said plate of homogeneous illumination (40) emitting homogeneous light over said plate (10).
  • each LED (42) emitting light divergently on the side of said plate (4G) 5 the light from said LEDs (42) exiting orthogonally in (43) the radiant face of said plate (40);
  • a light intensity controller (61) for manually adjusting the light intensity with the aid of a fixed polarizer and a moving polarizer, so that the laser beam from the laser light source (71) passes through said controller ( 61) of luminous intensity fixed to the tubular connection structure (S0, 62).
  • the invention also provides an LALLS optical detector equipment which use provides the following advantages:
  • the present LALLS optical detector equipment is useful for assessing in real time the degree of orientation and / or stretching of finished products in the form of films, fibers, vials, bottles, and the like, such as those produced by extrusion or extrusion-blow.
  • the invention further provides a method for real-time morphological monitoring of extruded polyphase systems comprising subjecting an extruded polyphase system to real-time analysis by the LALLS optical detector to determine the morphological properties of the extrusion process product and take any corrective action on the process in real time
  • FIGURE 1 is a graph of scattered light intensity profiles calculated from the Mie (plane wave) model for single-mode spherical particle size (one diameter) of refractive index 1.76 calculated for different diameters (as indicated) dispersed in a polystyrene matrix with refractive index of 1.59; wavelength of 632,8 nm non-polarized light in the 0 to 15 ° angle range with a resolution of 1 o .
  • FIGURE 2 shows the intensity profile of the diffracted Suz of a dispersed particle system.
  • the attached FIGURE 3 shows the diffraction pattern of small and large particles.
  • FIGURE 4 shows a side sectional diagram of the LALLS detector equipment according to the invention coupled to the head of an extrusion machine and its peripherals including laser source, conical darkroom, signal conversion and amplification box, analog / digital conversion board and laptop.
  • the attached FIGURE 5 is a schematic showing another way of assembling and using the LALLS detector equipment of the invention.
  • the LALLS detector is not rigidly coupled to any other equipment.
  • the laser source and the conical darkroom are joined by a rigid connection that holds them together.
  • This set is positioned surrounding the sample to be analyzed such that the laser beam passes through it. Examples of materials that can be used are plastic films and thin wall blown parts.
  • the maximum sample thickness is defined by the ability of the laser beam to pass through it to produce measurable scatter in the conical darkroom.
  • the cooling system may be dispensed with.
  • the peripherals are the same as those presented above, i.e. laser source, conical darkroom, conversion box and amplification.
  • FIGURE 6 is a schematic representation of a conical darkroom used in the detector equipment of the invention showing lateral tear for homogeneous illumination plate insertion. It may or may not have a cooling system attached. Also shown; detector plate containing phototransistors, homogeneous illumination plate of the phototransistors for leveling the same, signal conversion and amplification box, analog / digital conversion plate and portable user.
  • FIGURE 7 is a schematic drawing of the detector plate of the inventive detector equipment illustrating the physical arrangement of the ray-shaped phototransistors, with an offset of 33.75 ° between adjacent rays comprising nine rays with 10 phototransistors each plus one in the center. totaling 91 phototransistors.
  • FIGURE 8 is a schematic drawing of the arrangement that makes up the central phototransistor, inserted into a metal cylinder and physical barrier elements to the laser beam, including a metal blade with a small central pinhole and the plasticine layer.
  • FIGURE 9 shows the effect of the mathematical treatment for signal-response leveling of each phototransistor (Z axis) to the discrete variation of the light intensity incident on the detector plate generated by the homogeneous illumination piacea: (a) Response to signals uneven and (b) after leveling. For any level of illumination the treated response of each phototransisors after the mathematical leveling treatment is the same.
  • FIGURE 10 shows a qualitative analysis with the presentation of the 3D Scattering Curves of the variation in the scattered light intensity (Z) as a function of increasing the concentration of alumina particles AI2O3 (from 0.1% to 1.0). % by weight) dispersed in PS polystyrene solid films.
  • FIGURE 11 is a quantitative analysis for estimating the average particle size from the 3D Scatter Curve shown in Figure 10.
  • the light scattering profiles of PS polystyrene solid films containing particles are shown.
  • of dispersed AI2O3 alumina having a mean diameter (D50) of 0.58 pm, with different percent mass concentrations.
  • D50 mean diameter
  • the curves calculated by the Mie scattering model for spherical particles with single diameters of 0.5 and 1.0 micron are also shown.
  • the experimental points obtained in real time are positioned between the two reference curves, indicating that the average particle size present in the sample is between these two limits, which agrees with the value estimated by other techniques, showing the quantitative efficiency of the equipment.
  • FIGURE 12 presents the quantitative analysis of the data in Figure 11 showing the average scattering profile formed by the mean values of the scattered intensities in polystyrene films having different percent mass concentrations of 0.58 microns d dispersed ayline particle. average diameter.
  • FIGURE 13 is a graph showing the Spread Profiles calculated by the Mie model for an AI2O3 paiticulated amyloid polymeric compound with diameters ranging from 0.5 to 4 microns dispersed in a polystyrene medium, profiles already shown in For simplicity, such curves were fitted to a linear behavior with constant intercept for all curves at, 167 and particle size dependent variable slope.
  • FIGURE 14 shows the variation of the slope of the straight lines adjusted to the Normalized Spread Profiles calculated by the Mie model for any medium / dispersed phase as a function of the average particle size of the dispersed phase.
  • FIGURE 15 shows the scatter profile (in dark squares) obtained inline with the aid of the optical device of the invention for the particulate particulate aiumin polymer having a previously measured mean diameter of 2.4 microns dispersed in a stream. softened polystyrene. For immediate visual comparison, these experimental results are superimposed on the linear curves adjusted for different ideal rigid spherical particle sizes obtained from Figure 13.
  • the attached FIGURE 16 illustrates the change in symmetry of the 3D Spread Curves from circular to an elongated pattern with increasing level of unidirectional stretching (from 2X to 6X) of HDPE / LLDPE blends solid films (80/20 ). The films were stretched in the Y direction and the laser intensity was adjusted to obtain the best resolution.
  • the attached FIGURE 17 illustrates the response of some phototransistors during obtaining the scatter profiles shown in Figure 16. Lower leveling limits (LIN) and upper leveling limit (LSN) are shown for direct comparison. Sample NE is for unstretched film. For the analysis to be quantitative, the points must fall within the LIN-LSN range. This Figure should be shown in real time on the screen during measurements as it serves as a reference for the system operator to accept the results shown by observing if the points fall within the LIN-LSN range.
  • LIN leveling limits
  • LSN upper leveling limit
  • the attached FIGURE 18 obtained with the optical device of the invention, presents a sequence of 3D Scatter Curves showing the variation of scattered light intensity (Z axis) as a function of the change in concentration of scattered alumina particles in a flux.
  • of PS softened during the extrusion residence time showing quasi-circular symmetry.
  • the symmetrical pattern indicates that the dispersed particles are spherical and not oriented.
  • FIGURE 19 shows the 3D Scattering Curve of a single ethylene polyethylene terephthalate (PET) fiber measured in two perpendicular directions, showing intense laser light scattering due to the large orientation of the crystalline amorphous phases in the ie longitudinal pull direction. fiber. The scattering occurs in the direction perpendicular to the longitudinal orientation of the fiber,
  • PET polyethylene terephthalate
  • FIGURE 20 shows the variation in the pattern of the 3D Scatter Curve during the extrusion of a PS flux dispersed PP polymeric mixture showing an X-axis aligned crest characteristic of an elongated dispersed particle flow in the direction. flow rate or extrusion, which corresponds to the Y axis.
  • a fixed amount of PP was added to the PS stream and predefined time over the entire period of residence (as indicated). Data obtained with the aid of the optical device according to the invention.
  • photoelement phototransistor
  • Photosensitive element are used interchangeably.
  • the operating principle of the present optical detection equipment is based on Low Angle Laser Light Scattering (LALLS), in which a collimated monochromatic light beam from a laser light source focuses ⁇ orthogonally on a transparent sample (solid, liquid or aerosol). Part of the light is then scattered by the present scattered phase and follows divergent paths.
  • LALLS Low Angle Laser Light Scattering
  • a detector plate which may consist of distinct detection elements (phototransistors, Charge-up Device - CCD, etc.) collects light intensity at various points whose positions are related to the scatter angle,
  • the reading of the light intensity at each point provides information about the scattering or diffraction pattern, according to the physical model adopted, and to which are attached certain morphology and dimensions of the scattered phase that originated said scattering pattern. It is also possible to obtain information about the degree of anisotropy of morphology, related to its degree of orientation. This gives real-time microscopic information about the morphology of the material analyzed.
  • LALLS optical detector equipment in the present invention generally designated by numeral (100), includes: alignment system (70) of laser light source (71); darkroom (20) (conical or not); cooling system (30), said system is required only when said darkroom (20) is operated in contact with a hot surface; detector plate (10) containing at least one photosensitive element (12) 90 prototypes were installed. radially distributed (plus one in the center, said central phototransistor); rigid tubular frame (60) securing the laser light source alignment system (70) (71); .
  • the detector equipment 100 of the invention For the operation of the detector equipment 100 of the invention, it must be connected to a microcomputer 95, on which monitoring and control software must be executed.
  • the optical detector equipment 100 includes a control circuit (not shown) containing the embedded software.
  • the software (embedded or not) must perform two basic types of operation: i) receive a data stream for collection, mathematical manipulation and real-time screen display of signals as well as ii) send a data stream for automated management and control of the grading system.
  • detector equipment (100) is coupled to an extrusion die (50) (of any geometry), which has thin, flat-faced transparent windows between which molten (or softened) polymer material must flow (sample (61)). ) and through which the incident laser light beam from the Suz laser source (71) and the scattered laser light beam reaching the detector plate (10) shall be transmitted.
  • optical detector equipment (100) can be assembled in several ways: 2017 000014
  • the component parts are fixed according to the scheme of Figure 4.
  • the alignment system (70) of the laser light source (71) is fixed, the beam passes through a light intensity controller (61) fixed to. tubular connection structure (60).
  • the darkroom (20) defined herein as conical, on the bottom of which the detector plate (10) is secured.
  • FIG. 5 Another way of assembling and using the inventive LALLS optical detector equipment (100) is that shown in Figure 5.
  • This assembly is positioned surrounding the sample (51) to be analyzed such that the laser beam passes therethrough.
  • This also involves sequential and continuous measurement of moving parts on a conveyor belt (not shown). Examples of materials that can be tested in real time are plastic films and thin-wall blown parts, such as vials, disposable PET liquid bottles.
  • the required peripherals are the same as those given above, i.e. the alignment system (70).
  • the LALLS detector equipment (100) requires a collimated, averaged monochrome (emission band as narrow as possible) beam of monochrome electromagnetic radiation for its operation. intensity obtained from a laser light source (71).
  • the laser beam must be centered in such a way that it is orthogonally incident to the detector sink (10) reaching its center point.
  • the sink 10 has at least one phototransistor, photodiode or center point! of a CCD to be used to center the alignment (70) of the laser light beam.
  • a light intensity controller (61) is positioned in the optical path between the laser light source (71) installed within the laser light source alignment system (70) and the slot matrix (50).
  • a He-Ne model 05-LHP-401 laser manufactured by Meiies Griot was used. This laser has a nominal wattage of 1 mW and emits radiation at wavelengths. 632.8 nm, linearly polarized. However, radiation with other wavelengths may be used, as long as those in the region ⁇ ; - : 1: nf ' ⁇ e ⁇ e3 ⁇ 4feo?: A ⁇ : rTio-r is visible to those contained in the region.:: T ⁇ ltFá3 ⁇ 4Ie ⁇ 3 ⁇ 4t ; Therefore, it is necessary for morphologies of varying dimensions to be detected and quantified. Also unpolarized monochrome collimated fonts can be used.
  • the light intensity controller (61) consists of a pair of linear polarizers, one fixed polarizer (with its polarization axis aligned with the direction of flow fused into the slot matrix) and the other movable polarizer, free to be manually rotated in an angle of at least 120 ° about the optical axis of the laser beam and counted from the optical axis of the fixed polarizer.
  • the luminous intensity of the laser beam can be reduced by rotating the moving polarizer from the angle. Zero when both polarizers have their optical axes parallel and extinction is minimal.
  • the extinction gradually increases, reducing the light intensity of the maschine beam until it reaches its maximum extinction value occurring at 90 °, a position known as cross polarizers.
  • the adjustment of the best light intensity is done manually and depends on the degree of transparency of the sample to be analyzed in real time, which may be a molten flux, hollow parts (ie disposable bottles), thin films, etc., of different thicknesses.
  • the transmitted and non-scattered laser light beam must strike the detector plate (10) exactly in its center, reaching the central phototransistor embedded in (11). For this to happen it is necessary to align the laser source which is done by the laser alignment system (70).
  • Various mechanical shapes can be used to achieve this purpose.
  • One, used in making the prototype of the present application, is a thin-walled metal tube into which the laser light source 71 is inserted longitudinally.
  • the front end of said source (71) (through which the laser light beam exits) is fixed to the end of the thin-walled metal tube to allow slight movement with respect to its axis of longitudinal symmetry.
  • the other end of the laser light source (71) is spatially positioned with three long, coplanar metal pins orthogonal to the axis of symmetry and offset by 120 ° each. Two of these pins are screws that can be handled on the outside of the metal tube such that when threaded they move into and out of the metal tube by lightly pushing the laser light source.
  • the third pin is attached to a spring that forces it against said laser light source (71) while holding it against the other two pins. By threading each of the two pins it is possible to position the back of the laser light source (71) to allow alignment of the laser light beam.
  • the detector plate (10) is very sensitive to light, so it should be in a dark environment, which will not allow any external light to come in, except that from light scattered by the sample to be analyzed.
  • a darkroom (20) rigid enough to maintain the fixed positioning of the detector plate (10) relative to the light beam from the iaser light source (71) was designed.
  • the darkroom (20) is metal and internally coated in a dull black color to minimize internal reflections that would interfere with the measurements.
  • said chamber (20) is constructed of another lighter metal (aluminum and its alloys, Zamac, folded tinplate, etc.) or, in case the equipment is operated in contact with samples at room temperature or up to 100 ° C. ° C of plastics material (injected plastics, fiberglass reinforced plastics, etc.).
  • the geometry of said darkroom (20) is any, usually conical, requiring an opening to allow light scattered through the sample to be projected onto the detector plate (10). positioned at the bottom of said darkroom.
  • LALLS detector equipment 100 has been assembled with a conical darkroom 20, as this is the geometric shape that envelops the scattered light in an integral and compact manner.
  • the conical darkroom (20) is constructed from a rolled steel sheet forming a blunt cone with a circular opening 20 mm where the scattered light enters. On the other side, the cone has a circular bottom of 119 mm in diameter where the detector pin (10) is fixed.
  • These dimensions were used in the prototype f (1) of the detector equipment 100 of the invention, but are not critical and can be changed to best suit the required configuration, keeping only the solid cone opening angle under control. 15 °, but may vary more or less to include more or less angles.
  • a cooling system (30) (see Figure 4) is required to prevent heat conduction from the heated die (50) to the extrusion.
  • sensitive detector plate (10) One of the forms of construction of the cooling system (30) is to secure a coil-type cooling system wrapped around the base of the metal cone (small diameter zone), and may be a copper duct (20), allowing the circulation of a coolant, usually water but not limited to it.
  • Said darkroom cooling system (30) is dispensable when it is not in direct contact with a heated surface, ie when the equipment is used to analyze in real time the production of films and fibers. plastics, already solidified and partially cooled.
  • the darkroom (20) should have a side opening (slot) (41) near the detector plate (10).
  • the opening (41) serves to insert the homogeneous illumination plate (40) for leveling the response of the photosensitive elements (12) present in the detector plate (10), as shown in Figure 6.
  • the detector plate (1.0) is responsible for quantitatively and spatially defining the intensity of laser light scattered by a sample (51) being analyzed.
  • said plate (10) contains an array of photosensitive elements (12), or a single integrated photosensitive element, such as a CGD (not shown).
  • These elements (12) are transducers that convert radiant energy into an electrical response.
  • each detection point has its known position and the joint analysis of all its responses gives the 3D Scatter Curve.
  • the position of each detection point corresponds to a given scattering angle, defined by the arc whose tangent is given by the relationship between the distance from said point to the center of the detector plate and the distance from the detector plate to the sample, either thin film, hollow solid part surface, a molten flow, etc. In the proposed equipment such angles are between 5 and 15 degrees.
  • photosensitive elements (12) 90 radially positioned phototransistors plus one (total 91) positioned in the center of the detector plate used for the centering of the laser beam were used as photosensitive elements (12). and quantification of the scattered transmitted light, which provides the system turbidity.
  • other photosensitive elements (12) may be such as photodiodes or a CCD.
  • the detector 100 must also include a set of strands for focusing the scattered light.
  • Figure 7 shows the arrangement of the 91 phototransmitters- (12) of the LALLS detector (100) Prototype III detector plate, forming radii (numbered 1 to 9) offset by 33.75 ° (270 8) a on the other and occupying three quadrants (270%
  • This arrangement was chosen because it requires the least amount of photosensitive elements (12), obtaining the largest amount of information per area, ie, having the highest resolution.
  • At least two orthogonal symmetry axes in the 3D Scatter Curve pattern it is possible to distribute the measuring radii in three quadrants and the bounded information shifted to each of the other three quadrants. 11, 25 ° (908) each other, which generates 321 points (91 real and 230 virtual.)
  • Such a physical arrangement allows, from a restricted number of photosensitive elements (12), to virtually quadruple the number of reading d the same.
  • the phototransistor centers! (12) By receiving the non-scattered, high intensity laser beam, it should be protected from this high intensity.
  • One way to protect it the one used in the construction of Prototype III of LALLS Optical Detector Equipment (100) is shown in Figure 8.
  • the central phototransistor (12) is encapsulated at the bottom of a light-absorbing well formed by a small hollow stainless steel cylinder (11) of 3 mm internal diameter by 10 mm high into which a Thin metal blade with a small hole (pineJe) and above it a layer of black plasticine.
  • Black plasticine strongly absorbs radiation from the incident Suz laser beam by reducing the intensity of said beam to levels compatible with a phototransistor's beam capability, allowing quantification of said beam by the central phototransistor positioned just below it.
  • the central phototransistor is used in two functions; (i) laser beam alignment and (ii) to quantify the intensity of the transmitted and non-scattered beam as it passes through the sample (51), ie it measures the turbidity of the medium.
  • Turbidity measurement can also be used to calculate the average particle size of the second dispersed phase in the sample, provided that its concentration is known, which result can be compared to the measurement made by light scattering.
  • Another important feature of the turbidity measurement in the case of using the present LALLS detector equipment (100) in an extruder is that this measurement enables the determination of the residence time distribution curve of the molten polymer during its travel through the extruder. along the extruder.
  • Such multiple electronic circuits are installed in a signal conversion and amplification box (80) (see Figures 4 and 6).
  • the box 80 In case of use of the CGD type photosensitive element, the box 80 must also contain the electronic circuits responsible for its analog / digital conversion.
  • Each electronic box circuit 80 produces a voltage signal (Vout) from each of the phototransistors present on the detector board 10 which is converted by an analog / digital conversion board (AD / DA) (90). ) multichannel and then sent to a portable computer (95).
  • the computer (95) coupled to the detector equipment (100) sends a signal via the AD / DA board (90) to the electronic circuit in the box (80) ' which then alters the light intensity emitted by the array.
  • LEDs (42) are fixed to the side of the leveling plate (40), discreetly and stepwise changing the light intensity emitted by the leveling plate (40).
  • Photosensitive elements respond in a unique and unique way to the light stimulus. Thus different photoefficiencies present answers that are slightly different from each other. In case of using a arrangement of discrete photosensitive elements, their responses have to be normalized, said level here, so that they can be comparable point to point. In addition, the photoelement response is almost always nonlinear with respect to the variation of the light intensity incident on it and should be quantified.
  • leveling or normalization
  • the leveling system allows all photodetector responses to be within the same range, ie normalized. For this, it is necessary to build a hardware component, and its software:
  • This consists of a homogeneous illumination plate (40) which emits homogeneous Suz over all the area of the detector plate (10), as shown in Figure 6.
  • the homogeneous illumination plate (40) consists of a transparent plate with an array of LEDs (42) arranged side by side positioned on the edge thereof. Each LED (42) emits light divergently on the side of said transparent plate (40), through which light is transmitted and reflected (internally) over its entire length.
  • One of the surfaces of the plate 40 is provided with a texture which renders it translucent on this side; This is where the light from the LEDs (42) will come out of the plate (40), orthogonally to it as shown by the set of arrows (43) in Figure 6.
  • three types of plastic films (not where the light will pass before it leaves the leveling plate 40: a first spreading film, a prismatic film and a second scattering film. All of this makes it possible for light emitted by point sources (LEDs) (42) to be scattered and exited as a single source. light plane as shown by the set of parallel arrows (43) exiting the radiant face of the homogeneous lighting plate (40),
  • the LEDs chosen 42 emit in the narrow wavelength range and as close as possible, but not necessarily equal to, the wavelength of the laser light source 71.
  • the intensity of the light emitted by the LEDs should vary. unobtrusively at least 10 predefined intervals through a circuit eletrônico..espec ⁇ fico present in the housing (80) for conversion and signal amplification. the action of said circuit to be fully automated, ⁇ controlled by software.
  • Figure 9 shows the effect of signal leveling on Prototype IH of the built-in optical detector equipment (100) which has a detector plate (10) composed of phototransistors.
  • This figure comprises two sequences of images with the (a) non-leveled signals and (b) after the leveling or normalization mathematical treatment. Without leveling, Figure 9 (a), obtained from the phototransistor signals without mathematical treatment, the response of each phototransistor (12) is particular and different from the others, preventing their collective use to form the Scattering Curve 30. .
  • the leveling system therefore comprises the homogeneous illumination plate 40 and the mathematical treatment of the signals emitted by the phototransistors 12 carried out by embedded software or not, as already described above in this report.
  • control board containing an integrated circuit, for example of the type Program Integrated Circuit (PIC), in which the embedded software responsible for all real-time operation resides. of the equipment described herein.
  • PIC Program Integrated Circuit
  • the output interface can be an LCD display where the system can be configured and where the results of interest can be displayed.
  • This LALLS detector control system can also include a microcomputer compatible output port (USB, serial, parallel etc).
  • said structure (60) is comprised of a brass machined tube with fittings of the quick coupler type (not shown) for fast and practical attachment of said structure (60) to the extrusion die (50).
  • FIG. 5 Other forms of support may be required depending on the type of analysis to be performed.
  • the system is designed to be operated for analysis at or just above room temperature, for example up to 100 ° C of finished products. Such conditions are typical in the characterization of already solidified extruded or blown polymeric films, extruded polymeric fibers, blown bottles and bottles, etc.
  • the frame (82) must also be rigid and light, made for example of aluminum or its alloys or even injected plastic.
  • Such a structure fixes the laser light source (71) directly to the conical darkroom (20) so as to maintain alignment of the laser light beam and the detector plate (10).
  • This arrangement allows solid samples (51) to be positioned in the laser optical path for analysis. Since the entire system operates at ambient temperatures, the conical darkroom 20 does not need to be refrigerated and can be made of injected plastic material.
  • These films were prepared by dissolving PS in chloroform, vigorously dispersing the ailine, evaporating the solvent and drying the film. Such a procedure allows for obtaining well-known and well-defined standard samples where PS forms the transparent matrix phase with the known particle size ayoline particles forming the dispersed phase.
  • LALLS optical detector equipment 100 was bench-tested by inserting these standard samples into the laser light beam and systematically varying the concentration of the dispersed phase of aiumin.
  • a necessary requirement for light scattering to occur is that the scattered phase (s) have different refractive index (s) from the matrix material and its dimension is of the order of wavelength of light would be incident. Such conditions are met in the system used.
  • concentrations used were low and incremental: 0.1; 0.3; 0.5; 0.7 and 1.0% by weight of polystyrene alumina powder. Observation of such curves is indicated when qualitative analysis is required only.
  • the 3D Scatter Curve shifts to higher values on the Z axis (the whole curve goes up) showing a continuous increase in scattered light intensity with increasing concentration of the scattered phase of alumina.
  • These 3D Scatter Curves are approximately circular. and remain as such with increasing concentration of aiumin, since they are films with approximately spherical particles and homogeneously dispersed in the polymeric matrix, without any preferential orientation.
  • the circular pattern of the 3D Scatter Curve remains constant regardless of particle concentration. This demonstrates the sensitivity of LALLS optical detector equipment (100) qualitative analysis to small variations in second phase concentration and orientation in an essentially amorphous matrix and its potential for use in real-time quality control during melt and product analysis. thin-walled materials, both made of polymer composites.
  • the graph shown in Figure 11 is shown, which is one of the possible forms of real-time ( ⁇ nin) screen presentation of the quantitative behavior of the medium in terms of the mean particle size of the second dispersed phase.
  • a first form of quantitative analysis of the data presented in Figure 10 is shown showing the light scattering profiles of PS polystyrene films containing 0.58 pm average diameter (D50) dispersed alumina particles under different percentage concentrations. in bulk, as shown.
  • D50 average diameter
  • the curves calculated by the Mie scattering model of these spherical particles with single and fixed diameters of 0.5 and 1.0 microns are the experimental points obtained in real time are positioned between the two reference curves, regardless of their concentration, indicating that the average particle size present in the sample is between these two limits, which agrees with the value estimated by other techniques, showing the quantitative efficiency of the equipment.
  • Figure 12 presents another step in the quantitative analysis of the data in Figure 11 where the individual profiles for each concentration were replaced by the average scattering profile calculated from the average of the scattered intensities at each angle and concentration. This is valid because the spreading profile, within the detection limits of the equipment (to be discussed later in Figure 18), is independent of the dispersed phase concentration. In this case, we have a better visualization of the points that are positioned between the two limits formed by the theoretical curves calculated according to Mie. To these experimental points can be fitted a line with parameters
  • Such parameters are used for the quantitative determination of the average alumina particle diameter, yielding a value of 0.80 microns very close to the value measured by other means which is 0.58 microns.
  • Figure 13 shows a possible proposal for simplifying the use of Normalized Spread Profiles calculated from Mie's theory. This is done by fitting straight lines to such calculated profiles for the different particle sizes. It has been observed that when the profiles are normalized to the maximum intensity calculated as a unit value, such profiles change little when the medium and dispersed phase materials are changed to particle sizes up to 2 microns. From this value some difference is observed. For the sake of simplification, we assumed here an equal average behavior for all possible systems, which average behavior could be simplified represented by lines with the same fixed Intercept value and equal for all lines of 1, 167, a value previously observed in data adjustment of Figure 12.
  • Figure 15 shows the procedure for the quantitative analysis of the spreading profile presented by the sample, following the method proposed here using the simplification of the Mie model.
  • the other points are then normalized and included in Figure 5, forming the curve with full square points,
  • Isotropic systems are systems that have the same property in any direction it is measured. On the other hand if the property value varies with the direction of measurement then the system is said to be anisotropic or anisotropic.
  • Anisotropy can be quantified and is usually a fractional number between zero and 1 (one), the larger and closer to 1 the greater the anisotropy.
  • Elongated particles e.g. fibers
  • elongated phases and / or aggregates, orientation of these structures in a preferred direction are examples of anisotropy systems. As various properties are affected by the orientation of these structures then it becomes necessary to know their existence and to quantify the degree of anisotropy.
  • the management system calculates the value of the degree of anisotropy in real time and displays it on screen, in the form of a number or in control graphs. The operator can then take corrective action. The system can also work in a closed manner, automatically feedback this information, changing the operating conditions with the intention of restoring the previously stipulated anisotropy degree.
  • a second form of bench validation employed high density polyethylene (HDPE) and low density linear polyethylene (LLDPE) blend films, the films being hot drawn oriented,
  • Such polymers are semicrystalline and the effect of stretch imposed on the film on the orientation of the crystalline phase was analyzed.
  • the films were obtained by extrusion-blowing and then hot-drawn in a roll-forming at different pull levels: 2, 3, 4, 5 and 6 times the initial length.
  • Such a procedure forces the rotation and reorientation of the dispersed crystals in the amorphous matrix increasing their degree of crystalline orientation along the machine direction (machtne di ction or MD). producing single-oriented fifmes called Machine Direction Oriented Film (MDO).
  • MD machine Direction Oriented Film
  • Figure 16 shows a sequence of real-time 3D Scatter Curves (in-line with increasing degree of stretching and therefore of the crystalline orientation of such HDPE / LLDPE bend mono-oriented solid films.
  • the 3D Scatter Curves show a circular, homogeneous and symmetrical pattern in all directions. With the increase of the degree of stretching and the consequent increase of the level of crystalline orientation, this circular scattering pattern is transformed into an elongated scattering pattern that is more characteristic (elongated) in mono-oriented structures, the larger the amount degree of stretch / orientation. In the system used for this validation the 3D Scatter Curve pattern changes radically from the 4x stretch ratio from circular to elongated.
  • Figure 17 illustrates an example of the response graph of six (6) phototransistors (12) positioned from C to H of radius 1 (see coding in. Figure 7) during obtaining the 3D Scatter Curves shown in Figure 1.
  • Figure 16 where HDPE / LDPE blended solid films with different monoorientation levels are used.
  • Other phototransistor sets (12) could be analyzed, increasing the reliability of the measurements.
  • the lower leveling limits (LIN) and the upper leveling level (LSN) are marked for direct comparison. The signals from each phototransistor (12) must all be within such limits, thus allowing the 3D Scatter Curves of the sample to be analyzed to be interpreted quantitatively.
  • Figure 18 shows the 3D Scatter Curve of a single Ethylene Polyerephthate (PET) fiber measured in two perpendicular directions.
  • Eia shows the intense scattering of laser light due to the large orientation of the amorphous and crystalline phases present in the fiber and oriented in the pulling direction i.e. fiber length. The intense scattering occurs in the direction perpendicular to the longitudinal orientation of the fiber.
  • transiently dispersed phase PS flux was used, with the second phase being added as pulses, either particulate alumina or PP polypropylene grains.
  • the alumina pulse consisted of 0.1 g of a 16.67% by weight masterbatch prepared by dissolving PS in chloroform, dispersing the alumina and further evaporating the solvent.
  • PP was added in the form of grains (peites), whose total mass was 0.15 g.
  • the process parameters were kept constant: a constant thread profile with some KB45 screw elements at a feed rate of 2 kg / h and a rotation of 75 rpm.
  • Temperatures of 200 ° C for alumina dispersion and 220 ° C for PP dispersion were used, except in the feed zone where the temperature was maintained at 180 ° C to avoid polymer agglomeration and feed blockage.
  • Figures 19 and 20 show the variation in the intensity of the scattered laser light (Z axis) forming the scattering pattern over time as the LALLS (100) optical detector passes through the pulse of alumina particles and of PP, respectively, during PS extrusion. This period of time between the introduction of the pulse in the The extruder feed and its complete output after passing through the detector positioned at the extruder outlet is known as DTR Residence Time Distribution.
  • the intensity of the scattered light is undetectable up to approximately 19Gs, known as induction time, period where the scattered phase is still inside the extruder and has not reached said LALLS detector. From this time the particle concentration increases and therefore the scattered light intensity reaches a maximum after approximately 280s.
  • the scattering intensity is proportionally higher with increasing scattering phase concentration. Note that the pattern of the Scattering Curve 30 remains circular in shape during the passage of the ceramic particle, as the particle shape is approximately spherical and not oriented under the conditions to which it was subjected.
  • Well-dispersed spherical particles produce the same scattering intensity at all of the scattering cone present at a fixed angle. This produces a symmetric 3D Spread Curve with respect to the Z axis, which is circular when viewed in a three dimensional (3D) image.
  • This circular 3D pattern can be seen in Figure 19, and is characteristic of a rigid spherical particle dispersion, as expected for the dispersion of alumina particles in a PS matrix.
  • Figure 20 shows the variation of the 3D Scatter Curve pattern quantitatively by light intensity. due to the passage of the second phase of PP during PS extrusion.
  • Spherical particles produce a circular pattern 3D Scatter Curve, as already mentioned for the particles or agglomerates of aiumin particles.
  • Ellipsoidal or elongated particles oriented in a given direction, usually that of extrusion or stretching due to the presence of shear stresses, generate an elongated 3D Scatter Curve, positioned in the direction perpendicular to their orientation, ie perpendicular to the flow or direction. machine (MD).
  • MD machine
  • Elongated pattern 3D spreading curves positioned orthogonally to the Y flow direction, shown in Figure 19 indicate that the dispersed particles of the second phase of PP are deformed (elongated) in the flow direction due to cisaihament imposed during extrusion.
  • the scattering pattern consists of the superimposition of the scattering of light typical of each one.
  • Such morphologies form along the height of the extrusion die channel, the optical path traversed by the laser beam.
  • the medium under analysis is solid, molten (or softened) or in liquid suspension form.
  • the present optical detector equipment (100) is useful, for example, in the real-time monitoring (identification and quantification) of the morphology of polymeric mixtures and compounds directly in the extrusion processing. This makes quality control much more efficient as it can be done in real time during product production rather than in the lab from samples removed from the stream. Such procedure is usually performed off-fine, with sample collection and post-laboratory testing.
  • Inline or real-time measurement provides the result during product production, allowing for immediate corrective action without waiting time.
  • the present application further comprises the management system of all operations including leveling of all phototransfers (12 ⁇ , laser beam alignment (70), - response response of all photo elements (12) including central photoelement, conversion of these signals into variables of interest in the characterization of the system with polyphasic material, on-screen presentation of graphs, curves and data of interest and data saving in txt-like planets.

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Abstract

L'invention concerne un équipement (100) de détection optique de diffusion de lumière laser aux petits angles (LALLS) en ligne, comprenant un système (70) d'alignement de laser, une source (71) de lumière laser, une plaque détectrice (10) et une chambre obscure (20), un système de réfrigération (30), une structure tubulaire (60, 62) de connexion, un boîtier (80) de conversion de signaux, une plaque (90) de conversion analogique-numérique et un ordinateur (95) pour l'exécution d'un logiciel de surveillance et de contrôle, ledit équipement comprenant, sur ladite plaque détectrice (10), un ensemble de 90 photo-éléments (12) et un photo-élément central (12) additionnel. Ladite chambre obscure (20) présente une ouverture latérale ou fente (41) pour l'insertion d'une plaque transparente (40) d'éclairage homogène pour nivellement de la réponse des photo-éléments (12), ladite plaque d'éclairage homogène (40) émettant une lumière homogène sur ladite plaque (10) et comprenant un ensemble de DEL (42) disposées côte à côte et positionnées au bord de celle-ci, chaque DEL (42) émettant une lumière de manière divergente sur le côté de ladite plaque (40), la lumière en provenance desdites DEL (42) sortant perpendiculairement en (43) par la face rayonnante de ladite plaque (40). Un régulateur d'intensité lumineuse (61) permet en outre d'ajuster manuellement l'intensité lumineuse de la lumière laser. <i /> L'invention concerne également les utilisations dudit équipement et le procédé de surveillance morphologique en temps réel de systèmes polyphasiques à l'aide de ce dernier.
PCT/BR2017/000014 2016-02-10 2017-02-10 Équipement de détection optique de diffusion de lumière laser aux petits angles (lalls) en ligne, utilisation de ce dernier et procédé de surveillance morphologique en temps réel de systèmes polyphasiques WO2017136910A1 (fr)

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BR102016002791-8A BR102016002791B1 (pt) 2016-02-10 2016-02-10 equipamento para detecção óptica de espalhamento de luz laser em baixo ângulo (lalls) in-line, uso do mesmo e método para o monitoramento morfológico em tempo real de sistemas polifásicos
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