WO2017136910A1 - Apparatus for in-line optical detection of low-angle laser light scattering (lalls), use of same and method for real-time morphological monitoring of polyphase systems - Google Patents

Abstract

An apparatus (100) for in-line optical detection of low-angle laser light scattering (LALLS) includes a laser alignment system (70), a laser light source (71), a detection board (10) and a pinhole camera (20), a refrigeration system (30), a tubular connection structure (60, 62), a signal conversion box (80), an A/D conversion board (90) and a computer for running monitoring and control software, the apparatus comprising on the detection board (10) a set of 90 photoelements (12) and an additional, central photoelement (12); the pinhole camera (20) having a lateral aperture or slot (41) for inserting a transparent plate (40) for homogeneous illumination and levelling the response from the photoelements (12), the homogeneous illumination plate (40) projecting homogeneous light upon said detection board (10) and comprising a set of LEDs (42) arranged side by side at the edge of the plate, each LED (42) emitting diverging light onto the side of the plate (40), the light from said LEDs (42) being orthogonally projected at (43) by the radiating face of the plate (40); and an illumination intensity controller (61) is provided to adjust manually the illumination intensity of the laser light. Also described are the uses of the apparatus and the method for real-time morphological monitoring of polyphase systems using same.

Description

 OPTICAL DETECTION EQUIPMENT FOR LASER LIGHT SPREADING LOW. UNIQUE UNIT (LALLS), USE OF MESIVIO AND METHOD FOR MORPHOLOGICAL MO.NITORANIENTO IN TEIVIPO

 REAL CA! WO POLYPHASIC SYSTEMS OF THE INVENTION

[0001] 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.

 BACKGROUND OF THE INVENTION

 When focusing on a homogeneous material the light can suffer four basic phenomena: transmission, reflection, absorption and refraction. In transmission, the incident light propagates through the material without changing its direction, but its polarization state may change. In the case of reflection, the incident light is absorbed and reissued by the surface atoms of the material. On 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.

If light falls on a heterogeneous material instead, so-called light scattering may occur. The scattering is caused by the reflection and refraction of the light by focusing on transparent particles dispersed in an equally transparent matrix, but with a refractive index different from that. If light rays are diverted from their beam without loss of energy, the phenomenon is called scattering. Elastic (or static), otherwise if energy is lost, it is called inelastic (or dynamic) scattering.

 A phenomenon distinct from scattering, and which is often confused with it, is the refraction of light. Like scattering, refraction also occurs in a heterogeneous material medium, but in this case the dispersed particles must be opaque. Because they are opaque, they either fully absorb light or have a very different refractive index from their surroundings and are large relative to the Juz wavelength.

 In diffraction, light is diverted from its trajectory as it passes between the scattered particles, generating interference between the waves, which is revealed by the formation of maximums and minimums in light intensity.

[0006] 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].

| 0007] According to Mie, 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.

where: k is the initial intensity of the light beam; k is the wave number, equal to 2π / λ; and r is the distance between the spreading center (sample) and the detector.

[0009] The refractive index is given by:

where: 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.

In addition, the ratio of particle circumference to wavelength in the middle (x) is defined by:

Of which: the wavelength of light; and D is the particle diameter

Being that:

h ^ - ^» · (7)

ψ ... (mx} „Ί χ) - mç _K {x _r . ^' mx}

Pi lm &} (8) (_ „ ^S <COS #)) (9) where: ξ, Ric the Riccati and Bessel functions, respectively, which express the decrease of light intensity with increasing distance and P _n ¹ the Legendre first order function .

 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.

In the case of a heterogeneous polyphase material medium containing light-opaque dispersed particles, i.e. formed of a material whose complex refractive index has either very high real or imaginary component, 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.

Fraunhoffer's diffraction theory considers a system with opaque, spherical particles whose diameters are greater than approximately 20 times the wavelength of the incident light. Thus, the spaces between the particles behave like openings or cracks through which light passes and diffract resulting in the Airy pattern. In this pattern, as can be seen from the graph in Figure 2, the angular position of the maximum and minimum intensity of the diffracted light is characteristic of the size of the particles that generated them. Thus, the diffraction angles (0) of each intensity maximum are closely related to the diffraction particle diameter (D), as shown in Equation 10. D sin Θ = m X m = 0, ± 1, ± 2, ... (rj) where m defines the order of the maximum.

 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.

SUMMARY OF THE INVENTION

Development of previous prototypes

 [0015] The development of the ~ LALLS Low Angle Laser Light Scattering detector operating in real time in the extrusion was through the construction of three prototypes, fruit of three master dissertations defended in the Science and Engineering Graduate Program. Materials, PPGCE of the Federal University of São Carlos, UFSCar.

[0016] Prototype 1 was created in 2005 from Juliano Conter Damiani's master's dissertation "Development of a ~ LALLS low-angle laser light scattering detector operating in real time in extrusion", the second Prototype I! in 2007 in Lidíane C's master dissertation. 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 dissertation ^" Improvement of a scatter detector low-angle laser light (LALLS in-iine) for real-time monitoring of the extrusion process ". The latter was presented closed to the public and with a confidentiality clause document signed by all members of the Examining Board to maintain unpublished the subject matter of this application. In the latter case several radical changes and additions of components and design and construction details have been made that make this Prototype II a modified equipment with new and unique features including: ease of operation, presence of automated operations, efficiency in obtaining results, broader operating range, etc. Such changes / additions, which have not yet been disclosed, are part of the present application.

 In the first two prototypes Prototype i and Prototype H were released the first two versions of this equipment, and its basic construction includes the following parts / components:

 1) Slot die: A metal die with a slit 1.5 mm thick, 15 mm wide and 25 mm long. This design remained constant in the other prototypes, i.e. Prototype II and Prototype IH.

2) 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. ) Laser Light Illumination Source: In Prototype f 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 In Prototype Π this radiation source has been replaced by a commercial monochrome, non-polarized and collimated helium / neon red laser source, elies Gríot, model 05-LHP-401, with a reactive power of 57.3pW and wavelength 632.8 nm This model remained constant in Prototype lii.

) Laser Source Alignment Bracket: In Prototype I such bracket was a refrigerated tubing that only fixed the laser pointer, with no possibility of alignment. This bracket has been replaced in Prototype II by a laser alignment system consisting of a thin-walled zinc-plated brass tube. The system works with a pin / spring and two screws arranged at 120 °. At the base of the tube is a bolt for laser locking after alignment. A rigid tubular structure fixes the light source to the slot-like array. This system was maintained in Prototype III,

) Darkroom: To eliminate interference from outside light, 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.

) elements: Prototypes I and Prototype li used cadmium sulfide (CdS) LDR (Hd t resistor-dependent) photocell-type photoelements for the detection of scattered light intensity. In 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: Esía 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. This distance is too small to be practically achievable (the smallest commercially available diameter of phototransistors is still large and does not allow such a physical approximation). This configuration of photo element positioning on the detector plate was already defined in Prototype I and remained constant in Prototype II and Prototype III. In the latter prototype, the number of photoelements was increased to 10 per radius plus 1 central totaling 90 + 1 and replaced the LDR photocells with PT phototransistors.

) Central photoelement: 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. For the proper functioning of this central photoelement 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. Such an arrangement was developed and used only in Prototype 111 and is one of the claims of this application.): 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. In Prototypes I and II 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. At leveling, always done before In any experiment with quantitative measurements, 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 phototransisíor 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. At the same time 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. In a staggered and discrete manner a total of 5 to 10 increases in intensity are made, obtaining a data set for each phototransisor. Using the least squares method to this data set an exponential curve of the type Y = a, EXP (bX) is fitted where: Y is the phototransisor response (in Volts); X is the supply voltage of the LEDs present on the leveling plate (in Volts); and "a" and "b" are the coefficients of the exponential adjustment model, amplitude and damping, respectively. From each curve adjusted for each of the phototransistors a pair of coefficients (a, b) that are stored. These coefficients are later used to transform the signal response (in Volts) of each phototransistor to a normalized value, called level (also in Volts). Desia forms all the response signals of each of the 90 phototransistors, because they are mathematically adjusted (or offset), will give the same value when subjected to the same light intensity. Thus all these signals can be quantitatively compared to each other, serving as the basis for constructing a response surface, as in the 3D Scatter Curve graph.

) Analog / Digital Conversion Board AD / DÁ: 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 Gualíty 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. In the Prototype III for external interface, two National Instruments model cards were used: NI USB-6225 (80 analog input and 2 output channels) and Ni USB-6218 (32 analog input and 2 output channels). Of these, all 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.

) Laptop: for the collection, calculation, storage of data and graphical presentation of the light scattering intensity produced by the flux in real time. 16} Operating System: US Prototype I and Prototype !! software was developed in DELPHI 5.0 for photocell signal pickup and on-screen display of data over time. For the operation of the NI Prototype, it was replaced by the more versatile National Instruments LabView 8.6 platform.

The main unpublished items that differentiate Prototype II described in the present invention from earlier prototypes I and II are:

 1} 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. 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).

2) Photoefemeníos: 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. For measures where transparent window birefringence may affect the results, 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.

} Physical properties measurable by the equipment described in the Invention: Interpretation of 3D Scatter Curves provides information on the morphology of the polyphasic system analyzed including: Dispersed phase concentration, dispersed phase mean particle size, orientation level or degree of anisotropy of dispersed phase, residence time distribution curve, among other variables. With this information it is possible to indirectly obtain real-time information on the degree of dispersion of the second phase, which helps to conclude on the quality and efficiency of the mixing system used in the extruder. The equipment proposed herein allows all these measures are carried out, involving complex optical _concepts' of simple and automated real time. Such versatility allows any minimally trained person to operate the proposed equipment, obtain experimental data, compare these with pre-set reference limits and thus control the quality of the material being analyzed. It is also possible to use the data obtained to automatically modify the operating conditions of the system via data feedback to automatically control the entire system.

[0019] The article "In-line optical techniques to characterize the polymer extrusion", Santos, AMC et al., Poíym. Eng. Sei., 54: 386-395, 2014. © 2013 Society of Piasics Engineers DOI 0.1002 / pen.23569 presents and discusses different techniques for in-line optical characterization of polymer melt flow when pumped from an extruder. M-line techniques of turbidity, birefringence and light scattering at low angle are mentioned, the latter subject being object of the present application. The publication presents a series of scatter pattern photos obtained from the distribution of residence times of an extruder with a webeam. Such a scatter pattern photograph is visually good, but it is non-quantitative and requires high-level technical knowledge in optimal physics for its interpretation. Therefore its use is restricted and not adapted to a lay operator in the subject. Unlike in the present application 90 + 1 phototransistors are used, arranged in a radial spatial position, all with their responses in terms of leveled light intensity, precisely so that the system response is quantitative. The leveling is therefore what allows the quantitative aspect of the LALLS system response proposed here.

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.

SUMMARY GIVES INVENTION

 Broadly, 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:

i). Analysis of the morphological characteristics of the melt polyphasic material: In this case, said intermediate because the sample is still a molten mass, 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. ii.) Analysis of the morphological characteristics of polyphasic material that produces finished products: In this case 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.

[0022] The uses of the present optical detector equipment for real time analysis of polyphase systems include:

 «Real time quality control of cast and solid systems;

 'Estimate of the average diameter of the particles contained in the samples;

 * estimation of the state of aggregation of these particles; and

 ® characterization of the presence and degree of orientation of the particles and / or dispersed phases.

[0023] The method for real-time morphological monitoring of molten state polyphase systems, said monitoring being performed on the output of an extruder comprises the following steps:

 1) adapting the LALLS optical detector equipment of the invention to a slot-like die installed at the outlet of an extruder for extruding polyphase systems;

2) insert homogeneous lighting plate with stepped intensity control in the darkroom and proceed to the automated cycle of leveling of the signals emitted by the phototransistors of said optical detector. In this automated procedure the coefficient pair of each phototransistor is obtained. After this normalization procedure is completed remove the homogeneous light plate from the darkroom.

 3) extruding said polyphase system through said slot-like die under extrusion conditions until stabilization;

 4) adjust the intensity of the laser beam by rotating the polarizing filter to produce on-screen scattering profiles within the lower (minimum) and upper (maximum) leveling limits, L1N-LSN;

 5) subjecting the polymer melt to real time analysis by low angle laser light scattering, in-line LALLS;

 6) from the signals sent by the detector plate and performance of the calculation system to quantify, in real time, the morphology of said polyphasic system through a Scattering Curve 30, and from this calculate the degree of anisotropy and / or molecular orientation. , mean particle size and other variables; and

 7) If the process conditions need to be corrected to obtain the desired morphology, make arrangements during the process.

 [0024] And 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:

 1) adapting the LALLS optical detector equipment of the invention into the production line of thin wall finished products made from polyphase systems;

2) position the darkroom inlet as close as possible to the finished product; 3) adjust the distance between the Saser radiation source and the darkroom to be as small as possible;

 4) inserting the leveling plate into the darkroom and proceeding to the automated leveling of the signals emitted by the phototransistors of said optical detector. In this automated procedure the coefficient pair of each phototransistor is obtained. After this leveling procedure is completed remove the leveling plate from the darkroom.

 5) with the finished product positioned in the laser optical path adjust its intensity, rotating the polarizing filter and producing in the web spreading profiles within the lower (minimum) and upper (maximum) leveling limits, Llfsí-LS;

 6) subject the finished product to real time analysis by low angle laser light scattering;

 7) from the signals sent by the detector plate and the performance of the calculation system to quantify, in real time, the morphology of said polyphasic system from which the finished product is made through a 3D Scatter Curve, and from it to calculate the degree of anisotropy and / or molecular orientation, average particle size, and other variables; and

 8) If the process conditions need to be corrected to obtain the desired morphology, make arrangements during the process.

Thus, 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:

(a) On said detector plate (10) for the quantitative and spatially defined capture of the intensity of laser light emitted by said laser light source (71) and scattered by a sample (51), a set of: /) 90 photoelements (12) forming numbered radii from 1 to 9 out of 33.75 ° (270 8) apart and occupying three quadrants (270 °) and // ^' ) one center photoelement! (1) additional encapsulated at the bottom of a light absorbing well formed by a small hollow cylinder (not shown) of stainless steel, pine board and black plasticine; for said 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). and comprising a set of side-by-side LEDs (42) positioned on the edge thereof, 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); and

 c) 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).

[0027] The invention also provides an LALLS optical detector equipment which use provides the following advantages:

 ® real-time quality control when preparing polyphasic polymer composites or thin-wall finished products, saving money;

 * estimate of the concentration of the second phase;

 ® estimate of mean particle diameter dispersed in samples;

'Characterization of the morphology of the polyphasic system, whether consisting of second phase particles dispersed in spherical or elongated form, via the degree of anisotropy;

 'Estimate of the degree of orientation of a given phase;

 'Estimate of the degree of dispersion of the second phase; and

® possibility of data feedback for process control during extrusion preparation of polymeric polyphase systems and in the production of thin-wall finished products selected from films, fibers, bottles, bottles. Additionally, 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.

[0029] 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

 BRIEF DESCRIPTION OF DRAWINGS

The accompanying 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 .

 The attached FIGURE 2 shows the intensity profile of the diffracted Suz of a dispersed particle system.

 Source: htiDs.y / www.svmpatec, com / EN / LaserDl raciion / LaserDiffraction. html

The attached FIGURE 3 shows the diffraction pattern of small and large particles.

 Source: https.Y / www.svnwatec com / EN / LaserPiffraction / LaserPiffraction. html

The accompanying 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. In this case 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. In this case 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.

 The accompanying 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.

The accompanying 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. [0037] The attached 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.

The accompanying 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.

 The accompanying 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.

The attached FIGURE 11 is a quantitative analysis for estimating the average particle size from the 3D Scatter Curve shown in Figure 10. In this Figure 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. For reference 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. The attached 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.

 The accompanying 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.

 [0043] The attached 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. The linear fit provides the Tilt ratio. = ~ G.054 * Diameter (in microns).

 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.

 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.

 The attached 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,

The accompanying 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.

DETAILED DESCRIPTION OF THE INVENTION

 According to the present invention, the terms "photoelement", phototransistor "." Photosensitive element "are used interchangeably.

[0051] 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. 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); ^. signal conversion and amplification box (80) with electronic circuits; homogeneous lighting plate (40) with stepped intensity control for leveling the photosensitive elements, said plate being inserted into a darkroom window or slot (41), analog / digital conversion plate (90) and laptop computer (95) According to Figure 4. In this Figure the flow of information and commands between the various elements is indicated by arrows in one or two directions.

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.

Alternatively, 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.

 In the case of application in the in-unit analysis of mixtures and extruded polymeric compounds. 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.

[0057] The optical detector equipment (100) can be assembled in several ways: 2017 000014

 31

i) One of the possible forms, particularly that adapted for in-line application in the extrusion process, the component parts are fixed according to the scheme of Figure 4. As shown in Figure 4, on the underside of the slot-like die (50) 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). On the upper side of the die (50) is coupled the darkroom (20), defined herein as conical, on the bottom of which the detector plate (10) is secured.

 ii) Another way of assembling and using the inventive LALLS optical detector equipment (100) is that shown in Figure 5. In this case there is the alignment system (70) of the laser light source (71) and the darkroom tapered (20) joined by a rigid connection (62) that holds them fixed and collinear. 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). Saser light source (71), conical darkroom (20), refrigerated or not, signal conversion and amplification box (80), analog / digital conversion board (90) and laptop (95).

Source ie laser light (71)

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).

In the prototype of the present LALLS detector equipment (100), 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 ^ e¾feo?: A ^ ^: rTio-r is visible to those contained in the region.:: TíltFá¾Ie ^ ¾t ^; Therefore, it is necessary for morphologies of varying dimensions to be detected and quantified. Also unpolarized monochrome collimated fonts can be used.

 Laser Beam Intensity Controller (61)

To control the intensity of the laser beam is installed in the optical path between the laser light source (71) and the conical darkroom (20) a light intensity controller (61), as shown in Figures 4 and 5. Said 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. As the angle increases, the extinction gradually increases, reducing the light intensity of the faser 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.

Laser Light Source Alignment System (70) (71)

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. Conical Darkroom (20)

 [0062] 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. To this end, 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. In the prototype of the present detector equipment (1.00), the darkroom (20) is metal and internally coated in a dull black color to minimize internal reflections that would interfere with the measurements. Alternatively 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.).

 After the laser beam from the source (71) is scattered across the sample (not shown), the light diverges in all directions. Of interest to LALLS detector equipment (100) only is that contained in a small solid angle of up to approximately. 15 °, positioned after passage through the sample (51).

 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.

 The prototype of 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.

 For the case of application in Une in extrusion, one of the various uses of the invention, 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.

Detector Board (10) The detector plate (1.0) is responsible for quantitatively and spatially defining the intensity of laser light scattered by a sample (51) being analyzed.

 As shown in Figure 7, 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. In either case, 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. It is possible to decrease the maximum spreading angle by increasing the distance between the detector plate (10) and the sample (51) by extending with the addition of a flanged tube segment between the chamber (20) and the detector plate. (10) (not shown). This allows quantifying larger structures. The scattering pattern is linked to the morphological characteristics of said sample (51) to be analyzed, serving to interpret and elucidate its morphology.

In the construction of the prototype of the present detector equipment (100) and LALLS, 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. However, other photosensitive elements (12) may be such as photodiodes or a CCD. In the case of the 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.

From the center line, orthogonal to the detector plate (10) and, considering the center of the sample (51), positioned at 175 mm, as reference point, the phototransistors (12) of each level ( A to J), fixed to the detector plate (10), allow quantification of the intensity of scattered laser light at the following angles: A = 3.25 ^c , B ~ 4.59 °, C-5.92 ^c , 0 = 7.26 ° E = ^¾ 8.58, F = 9.89 °, 0 11 = 18 °, H = 12.47 °, 13.74 ° = 1, J = 15.00 °.

[0075] 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.

Thus (i) the signal saturation is avoided by the direct incidence of the intense transmitted and non-scattered laser beam, and (i) the lateral reflection of the light is prevented by focusing on the central phototransistor surface, which would be the nearest neighboring phototransistors, particularly those with the smallest scattering angle (A ~ 3.25 °), thus negatively affecting the results,

 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.

 Signal Conversion & Amplification Box (80)

The tiny electrical response of each of the multiple phototransistors (12) present on the detector plate {10} (Figure 6) with radiation positioning! shown in Figure 7 must be amplified and converted to voltage signal across multiple electronic circuits.

Such multiple electronic circuits are installed in a signal conversion and amplification box (80) (see Figures 4 and 6). 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. In this same box (80) is also installed the electronic circuit used for the automatic control of the lighting intensity of the LED's (42), elements that illuminate the leveling plate (40), which in turn is responsible for signal leveling of all the phototransistors (12). Analog / Digital (A / D) Conversion Board (90)

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). There is also a circuit inside the conversion box 80 (not shown) dedicated to controlling the light intensity for the light plate leveling system 40 required in the case of multiple elements. When the corresponding software is executed, 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). Phototransistor Signal Leveling System (2) with Homogeneous Lighting 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.

 Thus the development and use of a leveling (or normalization) system is indispensable, as there is an intrinsic variation in the response sensitivity of each of them. Thus, 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:

Hardware

 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, called the radiant face, 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. In this same way 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),

Mathematical treatment software

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..específico present in the housing (80) for conversion and signal amplification. the action of said circuit to be fully automated, ^■ controlled by software.

 This acts by producing at least 10 levels of variation of light intensity represented by parallel arrows (43) illuminating the 90 phototransistors (12), the response of each of them is measured and the 900 signals are saved in a data file. of array type XY. For each phototransist.r (12) then an array of XY point pairs is generated which is fitted with an exponential curve of the type:

 Y = a.EXP (bX) (11) and its quantified coefficients "a" and "b". Such parameters are then archived for use during the measurement, when then the signal measured by each phototransmitter (1.2) will be converted to a level signal. This procedure constitutes the mathematical treatment or leveling of the signals and removes the individualized response factor of each phototransistor (12), producing signals that can be quantitatively compared with each other.

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. .

 After signal leveling, Figure 9 (b), obtained from the mathematical treatment of signals as described above in this report, the response of each of the phototransistors (12) to the same known discrete variation of illumination intensity becomes the same. This allows the analysis to be quantitative because the responses of each phototransistor (12) can be compared with each other,

Another important point is that the response of all phototransisors 12 varies exponentially with the variation (known and controlled) of the imposed light intensity, showing the efficacy and necessity of this mathematical treatment for signal leveling.

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.

 [0096] The above description refers to non-embedded software. The following describes the possibility of obtaining embedded software, still under development by the inventors of the present application.

 System to embed LÂLLS control software (under development)

In the alternative of obtaining the embedded software it is necessary to construct a 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. This includes laser beam alignment, signal leveling of all phototransistors with their acquisition and mathematical treatment, real time measurement of the sample with respective signal pick-up of all phototransistors, mathematical processing of these signals, screen display of curves and graphs including 3D scatter pattern and values of interest such as average size particle size, degree of orientation (anisotropy), etc. 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).

Rigid laser source support frame (60)

 [0G98] Given the need for the laser beam to strike the sample (not shown) and the detector plate (10) orthogonally, each part of the LALLS optical detector equipment (100) must remain motionless. Thus, all component parts are affixed to a rigid tubular connection structure (80, 62), metallic or not, shown respectively in Figures 4 and 5.

 In the case of the prototype equipment (100) of the invention shown in Figure 4 and used for real-time quantification of morphology during extrusion, 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).

[0100] Other forms of support may be required depending on the type of analysis to be performed. One of these possible forms is shown in Figure 5. In this case 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. It is 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.

 Validation of the proposed LÂL.LS optical detector equipment (100) On bench

 [0101] A first validation of the benchtop LALLS optical detector equipment (.100) used polystyrene (PS) plastic films, an essentially amorphous polymer, with a second dispersed particulate ceramic phase of aiumin (AI2O3, a).

 These films, specially developed for this purpose, 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.

 [0103] 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.

[0104] 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.

 Qualitative analysis via 3D Scatter Curve

[0105] Figure 10 shows the 3D Scattering Curves (in three dimensions) of the variation in scattered light intensity (on the Z axis) as a function of increasing Al2 O3 alumina particle concentration (mean particle size D50 = 0.58 pm) finely dispersed in polystyrene solid films. The 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.

 [0106] 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.

Quantitative analysis via simplified Mie Scatter Curve [010?] 3D Scatter Curves associated with dispersed particle polymeric systems allow, according to light scattering, make a quantitative analysis, for example, estimate the average diameter of the particles contained in the samples.

To this end, the graph shown in Figure 11 is shown, which is one of the possible forms of real-time (ínin) screen presentation of the quantitative behavior of the medium in terms of the mean particle size of the second dispersed phase. In this graph 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. For reference also shown are the curves calculated by the Mie scattering model of these spherical particles with single and fixed diameters of 0.5 and 1.0 microns. 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.

[0 09] This estimate is consistent with the traditional off-Hne characterization performed using commercial control equipment, which measured the median diameter of these particles to 0.58 pm.

There are, of course, differences between the measured points and the shape of the calculated curves, since the actual particles are polydisperse and not necessarily spherical and the theoretical model considers a monodisperse system of rigid spheres, ie all particles are spherical and It has the same diameter. Experimental points are therefore the result of overlapping various scattering profiles, weighted according to the volumetric fraction of each particle size fraction.

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

 Y = -0.00436 * x + 1.167 (12)

[0112] 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.

[0113] 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.

[0114] For determining the slope ratio of the adjusted lines and. Particle size was plotted in Figure 14. The variation of the slope of the lines adjusted to the Scattering Profiles is shown. Normalized by the Mie model for any middle / dispersed phase pair as a function of the average dispersed phase particle size. The slope provides the ratio:

 Slope = —0.054 * Diameter (μτή) (13) [0115] Thus knowing the slope of the straight line adjusted to the experimental points measured in real time, it is possible to estimate the mean diameter of the dispersed particles in the medium by applying the inverse relation of the equation. 13, ie:

 Diameter (μηί) = -18.5 * Inclination (14

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. Here the normalized Mie curves are replaced by lines with a common intercept (= 1, 167) and slope dependent on average particle size (Diameter (in pm) ~ - 8.5 ^* inclination)

 The intensity of scattered laser light was measured at the angles: 13 = 4.59 °, 05.92 °, 0 = 7.26 °, E = 8.58 °, F = .9.89 ° and 6 = 11, 18 °, converted to normalized intensity by setting the most intense, which is the first point relative to the smallest angle (B = 4.59 °) with a value equal to unity. The other points are then normalized and included in Figure 5, forming the curve with full square points,

 From this set of points a line is adjusted and its slope measured so that by applying Equation 14 it is possible to estimate the average particle size. In the case shown in the Figure the slope is -0.14 and the calculated diameter is 2.6 pm, very close to the value obtained by other means which is D50 = 2.38 pm.

[0119] Another form of lively presentation! is that, also shown in Figure 15, where the experimental points (full black squares) are translated by maintaining their same reading angles, same inclination and setting the intercept at 1,167 as previously mentioned. This displacement positions the points between simulated lines (circles, voids) that represent the behavior of single 2 pm and 3 pm particles, allowing for rapid visual assessment.

Orau's anisotropy

 [01203 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) with aspect ratio greater than 1. 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.

[01.2 1 By quantitative analysis of light scattering at low angles, it is possible to quantify the degree of orientation of scattered structures in the polymer matrix, whether in the form of scattered elongated particles, oriented polymeric phases, etc.

 [0122] The degree of anisotropy of a system can be calculated from equations 15 to 17 below:

Anisotropy (15)

 &

 sen - (16)

A 2

where ςι: yetor.de scattering, qx: component x of the scattering vector, qy: y component of the scattering vector, /: light intensity, n: particle refractive index, Á: laser wavelength, Θ: angle scattering, ί (θ): scattered intensity at angle θ, l & incident intensity,

 [0123] From the 3D Scatter Curve 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.

 [0-124] The result of this assay demonstrates the potential of the LALLS optical detector equipment (100) of the invention in the real time characterization of particle size or aggregation state.

Quantitative analysis of mono-orientated polymeric films

 [0125] 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).

 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.

 Initially at low degrees of stretching and therefore low levels of crystalline orientation 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.

 From the results, it is clearly noted that with the incremental stretching increase the crystalline phase morphology undergoes reorientation which becomes more pronounced from the 4X level of stretching. From 4X onwards, the morphology changes little with additional stretches, ie the degree of orientation reveals asymptotic behavior. The mono-orienation blow extrusion line operator can then decide the degree of orientation to be imposed on the film being produced not by the degree of stretching but by its actual effect on the orientation of the film, revealed by the LALLS method of analysis. ! ine proposed here. This shows the sensitivity of the LALLS detector of the invention also to changes in crystalline phase orientation in semicrystalline systems such as polymers and polymeric bends.

Operational range of phototransisors In order for the 3D Scatter Curves to be quantitatively analyzed, it is necessary that the level of light intensity measured by each of the 90 phototransistors be within the illumination range LIN .SN defined during the leveling of that level being made by the homogeneous lighting plate for leveling.

 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. In this graph 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.

[0132] One way of adjusting the phototransistor signal (12) to fall within such reading limits uses the Laser Intensity Control described above. In order for the phototransistor response to be within its readable range it is necessary that the scattered light intensity reaching them be between a minimum that is not affected by the LIN noise and a maximum that does not saturate their LSN response. To do so, the polarizing filter is shaken to such a position that most of the signals fall within the limits mentioned,

Effect of scatter orientation

[0 33] 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.

 Quantitative analysis during the extrusion process

LALLS {100} optical detector equipment has been tested in real time during the extrusion process of fused polyphase systems to evaluate two dispersed phase conditions: (i) a stable morphology from the polystyrene polymer composite / alumina (mean diameter Dso = 2.38 μητ) and (li) a variable morphology from polystyrene / polyprapylene (PS / PP) polymer mixtures.

 For these tests, 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.

 It is noted that 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.

 [0139] The intensity of the scattered light captured by said detector slowly decreases until 800s after the start of the experiment it becomes insignificant, defining the maximum residence time; and would be null again after a theoretically infinite time.

[0140] As with solid films, 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.

 [0142] 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.

[0143] 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.

 The same experimental procedure used to obtain Figure 19 is also used herein to study the dispersion of a PP pulse in a softened PS stream. Thus a fixed and defined amount of PP was added, in the form of a pulse, in the extruder feed zone. This shaft is carried by the PS flow per iodine the length of the extruder. It takes 250s for the dispersed phase of PP to reach the LALLS detector positioned at the extruder outlet. This is seen by increasing the intensity (Z axis) of the scatter pattern from this time.

 [0145] Over time the amount of PP increases and this is seen by the continually increasing intensity of the 3D Scattering Curve to its maximum at approximately 300s after pulse release, indicating the maximum concentration of scattering particles. From this time on the PP concentration reduces the 3D Scatter Curve intensity similarly, revealing an elongated scattering pattern, typical of high aspect ratio particles with ellipsoidal or fibrous geometries. The last dispersed phase fractions leave the extruder after approximately 1200s.

 Unlike the results obtained with the aiumin particulate (Figure 19), now, having as a second dispersed phase a polymer, has an unstable morphology, which changes with the temperature and stresses to which it is subjected. During the passage of the PP particles, the scattering pattern changes according to the shape of these particles.

[0147] 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). This elongation at the Scatter Curve 30 becomes more intense as the aspect ratio of the particles increases, resulting in a crest when the particles are fibrillary.

 [0149] 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.

[0150] It should be considered that in these polymeric mixture systems there is the coexistence of various morphologies, so 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.

In-line tests during extrusion demonstrate the sensitivity and rapid response of LALLS detector equipment (100) to small variations in second phase concentration and morphology, such as those shown in Figures 19 and 20.

 [0152] Real-time knowledge during the manufacturing process of a polyphasic material of the characteristic 3D Scatter Curve pattern reveals important characteristics of the present morphology. A certain amount of mathematical modeling is required to quantify the type and degree of orientation of the present morphology.

The medium under analysis is solid, molten (or softened) or in liquid suspension form. Thus 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.

 It may also be used to evaluate in real time the degree of orientation and / or stretching of polymer blend films. like those produced by extrusion or extrusion-blow.

 [0156] The quality control carried out afterwards not only takes the time to wait for results (which may take hours to days) but is also done on finished material. If any corrective action has to be implemented in production it will be time-lagged and this time may be long enough for the production of prohibitive quantities of classified material such as off-grade incurring increased production cost.

[0 57] Inline or real-time measurement provides the result during product production, allowing for immediate corrective action without waiting time.

 [0158] 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.

Claims

1) Mine low angle laser light scattering (LALLS) optical detection equipment including laser alignment system (70), laser light source (71), detector plate (10) and darkroom (20) system (30), tubular connection frame (80, 62), signal conversion box (80), AD conversion board (90) and computer (9S) for running monitoring and control software, said equipment being characterized by understand:

(a) On said detector sink (10) intended to quantitatively and spatially define the intensity of the laser light emitted by said laser light source (71) and scattered by a sample (51), a set of: photoelements (12) forming 1 to 9 numbered radii 33.75 ° (27078) apart and occupying three quadrants (270 °) and / ^" /) an additional central photoelement (12) encapsulated at the bottom of an absorbing well of Suz formed by a small hollow cylinder (11) of stainless steel, pine and black plastic sink, for said central photoelement (12) being directed, with the aid of the laser alignment system (70), the beam of light transmitted and non-scattered laser, additionally said central photoelement (12) being intended to quantify the intensity of the transmitted and non-scattered beam as it crosses the sample (SI) by measuring the turbidity of the medium;

b) in said darkroom (20), side opening or slot (41) for insertion of a homogeneous illumination transparent plate (40) for leveling the response of the photo elements (12), said homogeneous illumination plate (40) emitting homogeneous light above said plate (10) and comprising a set of LEDs (42) disposed side by side positioned on the edge thereof, each LED (42) emitting divergently on the side of said sink (40), the ! uz from said LEDs (42) exiting orthogonally on (43) by the radiant face of said piacea (4Q and

 c) a light intensity controller (61) for manually adjusting the light intensity with the aid of a fixed polarizer and a movable polarizer, so that the laser light beam from the laser light source (71) passes through said controller ( 81) of luminous intensity fixed to the tubular connecting structure (80, 62),

 Equipment according to Claim 1, characterized in that the scattering analysis of a sample (51) of extruded polymeric material comprises coupling said detector equipment to an extrusion die (50) provided with windows between which said material flows. molten or softened polymeric light, through said windows being transmitted both the laser light beam from the laser light source (71) and the scattered laser light beam reaching the detector pin (10) on the underside of the slot matrix ( 50) the alignment system (70) of the laser light source (71) is fixed and the beam passes through a light intensity controller (61) attached to the tubular connection structure (60),

 Equipment according to claim 1, characterized in that it alternatively comprises the alignment of the light source alignment system (70) (71) and the conical darkroom (20) by a rigid connection (62) which holds them in place. and collinear, forming a set positioned to surround the sample (51) to be analyzed in such a way that the radius will pass therethrough, and sequence measurement is made! and continuous movement of moving parts on a conveyor belt.

Equipment according to claim 1, characterized in that it decreases the maximum spreading angle by increasing the distance between the detector plate (10) and the sample (51) by extending with the addition of a flanged tube segment between the chamber (20) and the detector plate (10),

 Apparatus according to Claim 1, characterized in that the leveling of the signals emitted by the phototransistors (12) comprises discretely varying the intensity of the light emitted by the LEDs (42) of the homogeneous light panel (40) by at least 10 predefined intervals. by means of the electronic circuit of the box (80) in order to produce at least 10 levels of variation of light intensity represented by parallel arrows (43) illuminating the 90 phototransistors (12), the response of each of said phototransistors (12) being measured and the resulting 900 signals being saved to an XY matrix data file, and then generated for each phototransistor (12) a matrix of XY point pairs, said matrix being fitted with an exponential curve of type Y = aEXP (bX), the coefficients "a" and "b" being quantified and archived for use during the scattering measurement, as well as the sina! measured for each phototransistor (12) is converted to fate! It is possible to quantitatively compare the signals obtained by the various phototransistors (12),

 Apparatus according to claim 1, characterized in that it comprises small windows in the form of discs of clear glass, seated in a recess in the die (50) and glued with adhesive.

Use of the apparatus according to claim 1, characterized in that said use is, through the interpretation of the 3D scattering curves, the determination of the dispersed phase concentration, dispersed phase mean particle size, orientation level or phase anisopyricity degree. dispersion, distribution curve of residence times in order to obtain real-time information on the degree of dispersion of the second phase, determining the quality and efficiency of the mixing system used in the extruder.

 Use according to claim 7, characterized in that it is for the analysis of the morphological characteristics of the po- phasic material which produces finished products selected from films, fibers, flasks and bottles.

 Use according to claim 7, characterized in that it is for the real time quality control of cast and solid systems.

 Use according to claim 7, characterized in that it is in the estimation of the mean diameter of the particles contained in the samples (51}.

Use according to claim 7, characterized in that it is in the estimation of the aggregation state of the particles contained in said samples (51).

 Use according to claim 7, characterized in that it is in characterizing the presence and degree of orientation of the particles, and alternatively of the dispersed phases.

 Use according to claim 7, characterized in that it is in determining the level of orientation or degree of anisotropy of the dispersed phase of polyphase systems.

 Method for real-time morphological monitoring of polyphase systems with the aid of equipment according to claim 1, characterized in that said polyphase systems are in the molten state and said monitoring is carried out at the outlet of an extruder.

(50),

Method according to claim 14, characterized in that it comprises the following steps: a) adapting the LALLS optical detector equipment (100) of the invention to a die (50) installed at the outlet of an extruder for extruding polyphase systems;

b) inserting the homogeneous lighting plate (40) with stepped intensity control into the darkroom (20) and proceeding to the automated leveling of the signals emitted by the phototransistors (12) of said optical detector (100), in this automated procedure being obtained. the pair of coefficients of each phototransist (12), then after the normalization procedure remove the leveling plate (40) from said darkroom (20);

c) extruding said polyphase system through said die (50) under extrusion conditions until stabilization;

d) adjusting the intensity of the laser beam from the laser light source (71) with the aid of the controller (61) by rotating the polarizing filter to produce on a computer screen (95) scattering profiles within the lower (minimum) limits. and upper (maximum) leveling, LSN-LSN;

e) subjecting the polymeric melt, sample (51). real-time analysis by low-angle laser light scattering, LALLS in-ínin.ef) from the signals sent by the detector plate (10) and performance of the calculations system to quantify, in real time, the morphology of said polyphasic system using a 3D Scatter Curve, and from this calculate the degree of anisotropy and additionally or alternatively calculate the molecular orientation, mean particle size without being limited to these variables; and

g) if the process conditions need to be corrected to obtain the desired morphology, make arrangements during the process. A method according to claim 1, characterized in that the polyphasic system alternatively comprises thin wall finished products and said monitoring is applied directly to the production line.

 Method according to Claim 18, characterized in that it comprises the following steps:

 a) adapting the LALLS optical detector equipment (100) of the invention on the production line of thin wall finished products made from polyphase systems;

 b) positioning the darkroom inlet (20) as close as possible to the finished product;

 c adjusting the distance between the laser radiation source (71) and the darkroom (20) so as to be as small as possible;

d) inserting the homogeneous illumination plate (40) with stepped control ^'intensity in the dark chamber (20) and proceed to automatic cycle averaging of signals from the phototransistors (12) of said optical detector (100), this automated procedure being We obtained the pair of coefficients of each phototransistor (12), then after the normalization procedure remove the leveling plate (40) from said darkroom (20); e) with the finished product positioned in the laser light path from the laser light source (71) and adjust the laser intensity with the aid of the controller (61) by rotating the polarizing filter to produce profiles on the computer web (95) scattering within the lower (minimum) and upper (maximum) leveling limits, LIN-LSN;

f) subjecting the finished product to real time analysis by low angle laser light scattering; g) from the signals sent by the detector plate (10) and performance of the calculation system to quantify, in real time, the morphology of said polyphasic system from which the finished product is made through a 3D Scatter Curve, and from the calculating the degree of anisotropy and additionally or alternatively the molecular orientation, mean particle size, without being limited to these variables; and

h) if the process conditions need to be corrected to obtain the desired morphology, make arrangements during the process.