BR102016002791A2 - EQUIPMENT FOR OPTICAL DETECTION DETECTION OF LASER LIGHT ANGLE (LALLS) INLINE, USE OF SAME AND METHOD FOR MORPHOLOGICAL MONITORING IN REAL TIME OF POLYPHASE SYSTEMS - Google Patents

Description

IN-LINE LOWS LIGHT SPREAD OPTICAL DETECTION EQUIPMENT, SAME USE AND METHOD FOR REAL-TIME MORPHOLOGICAL MONITORING OF INVENTION FIELD 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 inline mode, that is, to follow the morphological characteristics of the material 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 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 deviation of the optical path of the incident light, due to the polarization of the electronic cloud of the constituent atoms of the material, with the interaction of the electric field of light.

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

[0004] A phenomenon distinct from scattering, and 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 their dimensions are large relative to the wavelength of light.

In diffraction, light is diverted from its path 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 particles as spherical, isotropic, non-magnetic and smooth-surfaced, dispersed in a non-absorbent medium [van de Hulst, H. C. Light scattering by small particles. New York: Dover, 128-129, 1981].

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 light, the scattering centers are far enough apart that interference can occur between the rays emitted from the different regions of the particle (see Jenkins, FA; White, E. Fundamentals of Optics. 3a ed. New York : McGraw-HilI, 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.

By the Mie model, the scattered light intensity ls for a spherical particle is a function of the relative refractive index (m), the number (x) and the scattering angle (0), as shown in Equation 1.

(D being: Io the initial intensity of the light beam; k the wave number, equal to 2π / λ, was the distance between the scattering center (sample) and the detector.

[0009] The relative refractive index, m, is given by: (2) where: np is the refractive index of the material making up the particle; and nm is the refractive index of the matrix material.

Furthermore, the ratio of particle circumference to wavelength in the middle (x) is defined by: (3) where: λ is the wavelength of light; and particle diameter (4) (5) where: (6) (7) (8) (9) where: ξ, funções the Riccati and Bessel functions, respectively, which express the decrease of light intensity with the increased distance and Pn1 the first order function of Legendre.

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 an imaginary component 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 polyphasic material medium containing light-opaque scattered particles, ie formed of a material whose complex refractive index has either very high real or imaginary component, the Mie Theory is simplified to the concept of Fraunhoffer diffraction. The phenomenon is called diffraction, and is characterized by the deviation of light as it passes tangentially to the surface of scattered 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 particles behave like openings or cracks through which light passes and diffracts resulting in the so-called 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 (Θ) of each intensity maximum are closely related to the diffraction particle diameter (D), as shown in Equation 10. (10) where m defines the order of the maximum.

Patent documents aiming at online characterization generally deal with methods involving the segregation of a process stream and analysis of its morphological characteristics by any method, which differs from the present process, said inline that 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 20090306311. SUMMARY OF THE INVENTION

Development of previous prototypes The development of the LALLS Low Angle Laser Light Scattering detector operating in real time in the extrusion occurred through the construction of three prototypes, fruit of three master's dissertations defended in the Graduate Program in Materials Science and Engineering, PPGCEM, Federal University of São Carlos, UFSCar.

[0016] Prototype I was created in 2005 from Juliano Conter Damiani's master's dissertation “Development of a real-time extrusion low-angle laser light scattering detector - LALLS”, the second Prototype II in 2007 at Lidiane C. Costa's master's dissertation “Use of in-line LALLS in the extrusion of biphasic polymer systems” and the last said Prototype III, in 2015 in the master's dissertation of Thiago Manha Gasparini “Improving a laser light scattering detector in in-line LALLS for real-time monitoring of the extrusion process ”. The latter was presented in a closed manner to the public and with a confidentiality clause document signed by all members of the Examining Board to keep the subject matter of this request unpublished. In the latter case several radical changes and additions of components and design and construction details have been made that make this Prototype III a modified equipment with new and unique features including: ease of operation, presence of automated operations, effectiveness in achieving results. , wider operating range, etc. Such changes / inclusions, which have not yet been disclosed, are part of this application.

In the first two prototypes Prototype I and Prototype II were released the first two versions of this equipment, and its basic construction includes the following parts / components: 1) Slot matrix: a metallic matrix with a 1.5mm slot of thickness, 15mm wide and 25mm long. This design remained constant in the other prototypes, i.e. Prototype II and Prototype III. 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 blocks 20mm in diameter and 24mm in height. Its locking and sealing system involved a double locking 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 crushed the glass cylinder so that to prevent it from rupturing it had to be loosely tightened, limiting its use only to low pressures in the matrix slit of up to 300psi. This model remained constant in Prototype II, but was radically changed in Prototype III. 3) Laser light source: In Prototype I the light source used was a red laser pointer produced with a low cost (<7pW) solid wavelength, low efficiency solid semiconductor, ranging from 610 - 690nm and unstable behavior. In Prototype II, this radiation source was replaced by a monochrome, non-polarized, collimated monochrome, helium / neon red commercial laser source, Melles Griot, model 05-LHP-401, with real power of 57.3pW and wavelength 632 , 8nm. This model remained constant in Prototype III. 4) Laser Source Alignment Bracket: In Prototype I such bracket was a refrigerated tube 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. 5) Darkroom: To eliminate interference from outside light, the phototransistors were encased in a metal tube (tapered or not), with an angle of approximately 30 ° painted internally in a matte black color, to minimize the reflection of light 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 room temperature, the presence of the cooling system is not necessary, simplifying the assembly. 6) Photoelement signal leveling system: In the inner wall of the Prototype I darkroom, four red LEDs, arranged at 90 °, with wavelengths close to the laser light source and variable and controlled intensity, were introduced for leveling. each of the 64 phototransistors that constituted the detection system. Different levels of light intensity were produced by manually controlling the LED's supply current. Such a leveling system is not efficient because, 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 II, but was radically changed in Prototype III 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. 7) Photoelements: Prototypes I and Prototype II used cadmium sulfide (CdS) photocell-like LDR photocells to detect scattered light intensity. In Prototype III such sensors have been replaced by phototransistors that have much faster response (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 directly. This makes the LALLS detection system quantitative as presented in the present application, which differentiates it from earlier qualitative prototypes. 8) Detector plate: This consists of photoelements 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 arrangement of photoelements 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 just 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 positioning configuration of the photoelements 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 radius totaling 90 + 1 and replaced the LDR photocells with PT phototransistors. 9) 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 metal cylinder of 10mm in length and inner diameter equal to the outer diameter of the phototransistor (in the case of Prototype III of approximately 3 mm) has one end fixed over the phototransistor and the other remaining open. Inside 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 photoelement, is a thin metal foil with a small central hole of the order of 0.5 mm in diameter (pinhole), whose function is to allow the laser beam to be centralized. The second barrier, placed on this metal foil is composed of a layer of black plasticine that strongly absorbs the radiation reducing its intensity to 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 III, being one of the claims of the present application. 10) Extender Tube: (not shown) In Prototypes I and II the minimum spreading angle that can be measured is 3.25 °, which corresponds to a distance between sample and detector 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 detector plate. This tube increases the distance between the sample and the detector plate, thereby reducing the scattering 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. 11) Signal conversion and amplification box: This box packs the set of electronic circuits that allow quantifying the variation of the electrical resistance of the photoelements. 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 photocells 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. 12) 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 LEDs 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 the time of leveling, always prior to any experiment with quantitative measurements, said plate is inserted into a slit-shaped window on the side of the darkroom, allowing said plate to be positioned immediately over the phototransistors and with its radiant face facing towards phototransistors. Such arrangement allows to obtain the response curve of each phototransistor to the variation of light intensity incident on each said phototransistor and therefore to carry out quantitative analyzes of the scattered light intensity, object of this patent application. 13) Automated Phototransistor Leveling System: An automatic control and its respective software-managed mathematical treatment performs the signal-response 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 is collected from each phototransistor. The luminous intensity level of said homogeneous illumination plate is then automatically increased by obtaining a new measurement of the phototransistor response. In a staggered and discrete way, a total of 5 to 10 intensity increases are made, obtaining a data set for each phototransistor. 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 phototransistor 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) are obtained which are stored. These coefficients are later used to transform the response signal (in Volts) of each phototransistor into a normalized value, called level (also in Volts). In this way all the response signals of each of the 90 phototransistors, being 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. 14) AD / DA Analog / Digital Conversion Card: For Prototypes I and Prototype II to collect the voltage of each photocell and transform it from an analog to digital signal, a Quality 63 Kits external KIT 118 12BIT interface is used. which collects, 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 11 NI USB-6218 card acquisition channels were used. In this way all 91 signals are measured simultaneously and used for further analysis. 15) Laptop: for the collection, elaboration of calculations, data storage and graphical presentation of the light scattering intensity produced by the melt flux in real time. 16) Operating system: In Prototype I and Prototype II, the software developed in DELPHI 5.0 for photocell signal collection and on-screen data presentation as a function of time. For Prototype III operation it was replaced by the more versatile National Instruments LabView 8.6 platform.

The main unpublished items that differentiate Prototype III described in the present invention from previous prototypes I and II are: 1) Laser beam intensity control: Depending on the physicochemical characteristics of the sample to be analyzed (thickness, concentration of the second phase, orientation level, etc.) it is necessary to adjust the intensity of the laser light beam by increasing or decreasing it. In order for the phototransistor response to be within its usable range, the intensity must 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 to be presented and discussed later in this report). 2) Photoelements: The 64 light intensity sensors initially of the LDR type were replaced by 91 phototransistors that have much faster response (milliseconds), are more sensitive and have more predictable behavior. All are operated simultaneously. Their responses to light intensity were normalized, said leveled, so that the signals could be compared directly. The respective electronic circuits have been modified to operate such phototransistors. 3) Homogeneous illumination plate for leveling and normalization of 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 throughout the 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 side slit so as to position it with its radiant face directly over the set of all phototransistors.

4) 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 light 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. 5) Transparent windows: The double-locking cylindrical type windows disclosed in Prototypes I and II have been replaced by small discs in the form of clear glass discs which may be borosilicate, sapphire or other transparent material, 10mm in diameter and 1 mm thick, seated in a recess in the slot-like die and glued with adhesive. An example of adhesive may be Araldite type. For measures where transparent window birefringence may affect results, heat-treated borosilicate-based glass should be used to relax the frozen internal stress level. Such heat treatment can be done in muffle furnace at a temperature of 500 to 520 ° C for a time period of 5 to 24 hours. 6) 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 plate, thereby 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 flange length 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. 7) Computer Program: This program is responsible for all system control including: laser beam alignment, automated leveling of 90 phototransistors, collection of these same signals plus central phototransistor signal, data processing, screen display of various graphs particularly a 3D graph of 3D Scatter Curves and file recording. 8) Physical properties measurable by the equipment described in the invention: The interpretation of the 3D Scatter Curves provides information on the morphology of the polyphase system analyzed including: Dispersed phase concentration, dispersed phase mean particle size, orientation level or degree. dispersion phase anisotropy, 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 here allows us to perform all these measurements, which involve complex optical concepts, simply, automatically and in 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 “Online optical techniques to characterize the polymer extrusion”, Santos, A.C. et al., Polym. Eng. Sei., 54: 386-395, 2014. © 2013 Society of Plastics Engineers DOI 10.1002 / pen.23569 presents and discusses different techniques for in-line optical characterization of polymer melt flow when pumped from an extruder. In-line techniques of turbidimetry, birefringence and light scattering at low angle are mentioned, the latter being the subject of the present application. The publication presents a series of scatter pattern photos obtained during the distribution of residence times of an extruder with a webeam. Such a scatter pattern photograph is visually good, but it is not quantitative and requires high-level technical knowledge in optical 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 light intensity responses leveled, 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, etc.) to be automatically controlled via in-line feedback, produced and provided by the in-line LALLS equipment disclosed in this invention.

SUMMARY OF THE 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, Since the sample is still a molten mass, the LALLS optical detector equipment is installed on one side of a transparent window slotted array attached to the outlet of said extruder, 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 dark chamber (conical or not) with a cooling system, a detector plate containing at least one photo element, electronic signal conversion and amplification circuits and a 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), detector plate containing at least one photoelement, electronic signal conversion and amplification circuits and homogeneous lighting plate with stepped intensity control for photoelement leveling, said plate being inserted into a slot of said darkroom.

[0022] The uses of the present optical detector equipment for in-line analysis of polyphase systems include: • real-time quality control of fused and solid systems; • Estimation of the average diameter of the particles contained in the samples. • estimation of the state of aggregation of these particles; and • characterizing the presence and degree of orientation of the dispersed particles and / or phases.

[0023] The method for real-time morphological monitoring of molten state polyphase systems, said monitoring being performed at the output of an extruder comprises the following steps: 1) adapting the LALLS optical detector equipment of the invention to an installed slot type array 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 leveling cycle 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, LIN-LSN; 5) subject 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 the performance of the calculation system to quantify, in real time, the morphology of said polyphasic system through a 3D Scatter Curve, 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.

And the method for real-time morphological monitoring of thin-wall finished products (films, fibers, flasks, etc.) directly on the production line, made with polyphase systems, comprises the following steps: 1) adapt equipment LALLS optical detector of the invention in 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 laser radiation source and the darkroom to be as small as possible; 4) inserting the leveling plate into the darkroom and proceeding with the automated leveling cycle 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 complete remove the leveling plate from the darkroom. 5) With the finished product positioned in the laser optical path adjust its intensity by rotating the polarizing filter until producing on-screen spreading profiles within the lower (minimum) and upper (maximum) leveling limits, LIN-LSN; 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-source LALLS optical detector device comprising a darkroom provided with a detector plate containing photosensitive elements (phototransistors), the response of said phototransistors being leveled through a plate inserted into said plate. darkroom and positioned directly over the phototransistor assembly, such an optical detector device can be adapted on either side of the slot-like matrix of an extruder or a thin-wall finished product for the in-line measurement of system properties respectively during the course of production of the polymeric system in extrusion or as a finished product.

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 control comprises: a) On said detector plate (10) for quantitatively and spatially defined capturing 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 lagged 33.75 ° (27078) apart and occupying three quadrants (270 °) and //) an additional central photoelement (11) encapsulated at the bottom of a light absorbing well formed by a small hollow cylinder (not shown) of stainless steel, pin plate hole and black plasticine; for said central photoelement (11) being directed, with the aid of laser alignment system (70), the transmitted and non-scattered laser light beam, additionally said central 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 homogeneous illumination plate (40) for leveling the response of the photoelements (12), said homogeneous illumination plate (40) emitting homogeneous light above said plate (10) and comprising a set of LEDs (42) arranged side by side positioned on the edge thereof, each LED (42) emitting light divergingly on the side of said plate (40), the light coming from the said LEDs (42) exiting orthogonally at (43) by 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 light beam from the laser light source (71) passes through said controller ( 61) having a luminous intensity fixed to the tubular connecting structure (60, 62).

[0027] The invention also provides LALLS optical detector equipment, the use of which provides the following advantages: • real time quality control during the preparation of polyphase polymer composites or thin-wall finished products, resulting in savings: • estimation of the concentration of the second phase; • estimation of mean particle diameter dispersed in samples; • characterization of the morphology of the polyphasic system, whether it consists of second phase particles dispersed in spherical or elongated form, via 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, flasks, 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 a polyphase system in extrusion process to analysis by the LALLS optical detector object thereof in real time to determine 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 the scattered light intensity profiles calculated from the Mie model (wave in the plane) for single-mode spherical (one-diameter diameter) particles 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 °.

The attached FIGURE 2 shows the diffracted light intensity profile of a scattered particle system.

Source: httos: //www.svmpatec. com / EN / LaserDiffraction / LaserDiffraction.html [0032] The attached FIGURE 3 shows the diffraction pattern of small and large particles.

Source: https: //www.svmDatec.conn/EN/LaserDiffraction/LaserDiffraction.html [0033] Attached FIGURE 4 shows a side sectional diagram of the inventive LALLS detector equipment 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 steady. 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 laser beam's ability to cross it and 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 are: detector plate containing phototransistors, homogeneous phototransistor illumination plate for leveling them, conversion box and signal amplification, analog / digital conversion board and laptop.

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.

The attached FIGURE 8 is a schematic drawing of the arrangement comprising the central phototransistor, inserted into a metal cylinder and physical barrier elements to the laser light beam, including a metal blade with a small central pinhole and the plasticine layer.

The attached FIGURE 9 shows the effect of the mathematical treatment for signal-leveling each phototransistor (Z axis) leveling to the discrete variation of the incident light intensity on the detector plate generated by the homogeneous illumination plate: (a) Response to signals uneven and (b) after leveling. For any level of illumination the treated response of each phototransistor 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 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 also shown are the curves calculated by the Mie scattering model for spherical particles with single diameters of 0.5 and 1.0 microns. 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 mass percent concentrations of 0.58 microns dispersed alumina particle. average diameter.

The accompanying FIGURE 13 is a graph showing the Spread Profiles calculated by the Mie model for an AI2O3 particulate alumina polymeric compound having diameters ranging from 0.5 to 4 microns dispersed in a polystyrene medium, profiles already shown in FIG. For simplicity, such curves were fitted to a constant intercept linear behavior for all curves at 1.167 and particle size dependent variable slope.

The attached FIGURE 14 shows the slope variation of the lines fitted to the Normalized Spread Profiles calculated by the Mie model for any medium / dispersed phase pair as a function of the average particle size of the dispersed phase. Linear adjustment gives the ratio Tilt = -0.054 * Diameter (in microns).

FIGURE 15 shows the scatter profile (in dark squares) obtained in-line with the aid of the optical device of the invention for the previously measured average diameter particulate alumina polymer compound of 2.4 microns dispersed in a polystyrene stream. softened. For immediate visual comparison such experimental results are presented superimposed on the linear curves adjusted for different ideal rigid spherical particle sizes obtained from Figure 13.

The accompanying 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 accompanying FIGURE 18, obtained with the optical device of the invention, presents a sequence of 3D Scattering Curves showing the variation of scattered light intensity (Z axis) as a function of changing the 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 amorphous and crystalline phases in the pull direction ie fiber length. 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 a crest aligned in the X-axis direction 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 images were taken over the entire residence time (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 throughout the present scattered phase and follows divergent paths. A detector plate, which may consist of distinct detection elements (phototransistors, Charge-Coupled Device - CCD, etc.), collects light intensity at various points whose positions are related to the scattering 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 this 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: laser light source alignment system (70); 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) (in the constructed prototype 90 radially distributed phototransistors were installed 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 the signal collection, math manipulation and real-time screen operations as well as ii) send a data stream for management and automated leveling system control.

[0056] In the case of application in the Une analysis of extruded polymer mixtures and compounds, the detector equipment (100) is coupled to an extrusion die (50) (of any geometry), which has thin, transparent windows with flat faces. , between which the molten (or softened) polymeric material (sample (51)) must flow and through which the incident laser light beam from the laser light source (71) and the scattered laser light beam that strikes it shall be transmitted. the detector plate (10).

The assembly of the optical detector equipment (100) can be made in several ways: i) One of the possible forms, particularly that adapted for inline application in the extrusion process, the component parts are fixed according to the As shown in Figure 4, on the underside of the slot matrix (50) the alignment system (70) of the laser light source (71) is fixed, the beam passes through a controller (61) of light intensity fixed to the tubular connection structure (60). On the upper side of the matrix (50), the darkroom (20), here defined as conical, is coupled to the bottom of which the detector plate (10) is attached. 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 set 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 presented above, ie laser light source alignment system (70), conical darkroom (20), refrigerated or not, signal conversion and amplification box (80), conversion plate analog / digital (90) and laptop (95).

Laser Light Source (71) The LALLS detector equipment (100) requires a collimated, medium-intensity, monochrome electromagnetic radiation beam obtained from its operation to obtain its operation. from a laser light source (71). The laser beam must be centered in such a way that it hits the detector plate orthogonally (10) reaching its center point. The plate (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 laser, model 05-LHP-401, manufactured by Melles Griot was used. This laser has a nominal power of 1 mW and emits radiation at a wavelength of 632.8 nm, linearly polarized. However, radiation with other wavelengths can be used, from those contained in the infrared region, through the visible to those contained in the ultraviolet region. Such a wide range is necessary so that morphologies with varying dimensions can 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, a light intensity controller (61) is installed in the optical path between the laser light source (71) and the conical darkroom (20). ), as shown in Figures 4 and 5. Said light intensity controller (61) is formed by a pair of linear polarizers, being a fixed polarizer (with its polarization axis aligned with the direction of flux fused in the slot matrix) and the other movable polarizer, free to be manually rotated at 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 light intensity of the laser beam can be reduced by rotating the moving polarizer from zero angle when the two polarizers have their optical axes parallel and extinction is minimal. As the angle increases, the extinction gradually increases, reducing the light intensity of the laser beam until it reaches its maximum extinction value that occurs 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 (i.e. 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 does not allow any external light, except that from the luminous flux 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 laser light source (71) was designed. In the prototype of the present detector equipment (100), the darkroom (20) is metal and internally coated in matte black 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 source (71) is scattered throughout the sample (not shown), the light diverges in all directions, and of interest to LALLS detector equipment (100) is only that contained at a small angle. up to approximately 15 °, positioned after passage through the sample (51).

[0064] The geometry of said darkroom (20) is any, usually conical, requiring an opening to allow light scattered throughout the sample to be projected onto the detector plate (10) positioned at the bottom of said darkroom. .

The prototype of the LALLS detector equipment (100) was 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 plate forming a blunt cone with a circular aperture of 20 mm through which scattered light enters. On the other side, the cone has a circular bottom of 119 mm in diameter where the detector plate (10) is fixed. Such dimensions were used in the Prototype III of the detector equipment 100 of the invention, but are not critical and allow to be altered to better suit the required configuration, keeping only the solid cone opening angle under control. This is usually 15 °, but may vary more or less in order to include more or less angles.

For the case of inline application in extrusion, one of several embodiments of the invention, a cooling system (30) is required (see Figure 4) to prevent heat conduction from the heated die (50) to the extruder. sensitive detector plate (10). One of the forms of construction of the cooling system (30) is to attach a coil-type cooling system wrapped around the base of the metal cone (smaller 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 unnecessary when it is not in direct contact with a heated surface, ie when the equipment is used to analyze the production of films and fibers in real time. plastics, already solidified and partially cooled.

The darkroom (20) should have a side opening (slot) (41) near the detector plate (10). The aperture (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 Plate (10) The Detector Plate (10) 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 CCD (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 combined analysis of all its responses provides 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 LALLS detector equipment (100), 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 used, such as photodiodes or a CCD. In the case of the CCD, detector 100 should also include a lens assembly for focusing scattered light.

[0073] Figure 7 shows the arrangement of the 91 phototransistors (12) of the LALLS detector (100) Prototype III detector plate, forming radii (numbered 1 to 9) offset by 33.75 ° (27078) from each other and occupying three quadrants (270 °). This arrangement was chosen because it requires the smallest amount of photosensitive elements (12), obtaining the largest amount of information per area, ie, having higher resolution. Assuming that there are at least two orthogonal symmetry axes in the 3D Scatter Curve pattern, it is possible to distribute the measurement radii in three quadrants and the collected information bounced to each of the other three quadrants. This makes the virtual projection radii just 11.25 ° (9078) apart, which yields 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 points thereof.

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 (of 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 °, B = 4.59 °, C = 5.92 °, D = 7 26 °, E = 8.58 °, F = 9.89 °, G = 11.18 °, H = 12.47 °, 1 = 13.74 °, J = 15.00 °.

The central phototransistor (12) for receiving the high intensity non-scattered laser beam must 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 was inserted a thin metal blade with a small pinhole and above it a layer of black plasticine.

Black plasticine strongly absorbs radiation from the incident laser light beam by reducing the intensity of said beam to levels compatible with the readability of a phototransistor, 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 scattered laser beam and, ii) the lateral reflection of the light is prevented by focusing on the surface of the central phototransistor, which would be detected by the nearest neighbor phototransistors, particularly those related to the smallest scattering angle (A = 3.25 °), thus interfering negatively in 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 and Amplification Box (80) The tiny electrical response of each of the multiple phototransistors (12) present on the radially positioned detector plate (10) (Figure 6) should 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 CCD 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 LEDs (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) [0083] Each housing electronics (80) produces a voltage (Vout) signal from each of the phototransistors present on the detector board (10) which is converted by a multi-channel analog / digital (AD / DA) converter board (90) 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 changes the light intensity emitted by the LED array (42) fixed to the side of the leveling plate (40), discretely and staggeredly changing the light intensity emitted by the leveling plate (40). Phototransistor Signal Leveling System (12) with Homogeneous Lighting Plate (40) Photosensitive elements respond in a particular and unique way to the light stimulus. Thus different photoelements have answers that are slightly different from each other. If an array of discrete photosensitive elements is used, their responses have to be normalized, said level here, so that they can be comparable point to point. In addition, the response of each photoelement is almost always nonlinear with respect to the variation of 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. To do this, it is necessary to build a hardware component and its software: Hardware This consists of a homogeneous lighting plate (40) that emits homogeneous light over the entire area of the detector plate (10), as shown in Figure 6

The homogeneous illumination plate (40) consists of a transparent plate with a set 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 leaving 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 flat light source as shown by the set of parallel arrows (43) exiting the radiant face of the homogeneous light plate ( 40).

Software for Mathematical Treatment The chosen LEDs (42) emit in 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 slightly at least 10 predefined intervals by means of a specific electronic circuit present in the signal conversion and amplification box (80). The action of said circuit must be fully automated, controlled by the software.

This acts by producing at least 10 levels of variation in light intensity represented by the 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 phototransistor (12) an array of XY point pairs is then generated that 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 phototransistor (12) 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.

[0091] Figure 9 shows the effect of signal leveling on Prototype III of the built-in optical detector equipment (100) having 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 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 3D Scatter Curve. .

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, as the responses of each phototransistor (12) can be compared with each other.

Another important point is that the response of all phototransistors (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 for embedding LALLS control software (under development) [0097] In the alternative to obtaining embedded software, it is necessary to build a control board containing an integrated circuit, for example, the PIC (Programmable Integrated Circuit) type, where the embedded software resides responsible for all real-time operation of the equipment described herein. These include, laser beam alignment, signal leveling of all phototransistors with their acquisition and mathematical treatment, real-time measurement of the sample with respective signal collection from all phototransistors, mathematical processing of these signals, screen display of curves and graphs including the 3D scatter pattern and values of interest such as average 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 structure (60) Given the need for the laser beam to fall orthogonally to the sample (not shown) and to the detector plate (10), each piece of LALLS optical detector equipment (100) should remain motionless. Thus, all component parts are affixed to a rigid tubular connection structure (60, 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. This structure (62) 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. As 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 proposed LALLS optical detector equipment (100) Benchtop [0101] A first validation of the benchtop LALLS optical detector equipment (100) used polystyrene (PS) plastic films, an essentially amorphous polymer with a second ceramic phase alumina dispersed particulate matter (Al 2 O 3, a).

These films, specially developed for this purpose, were prepared by dissolving PS in chloroform, vigorously dispersing alumina, evaporating the solvent and drying the film. Such a procedure allows for obtaining well-known and well-defined standard samples where 0 PS forms the transparent matrix phase with the known particle size alumina 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 alumina phase.

[0104] A necessary requirement for light scattering to occur is that the scattered phase (s) have different refractive index (s) than the matrix material and dimension is of the order of the wavelength of the incident laser light. Such conditions are met in the system used.

Qualitative analysis via 3D Scatter Curve

[0105] Figure 10 shows the 3D Scatter Curves (in three dimensions) of the variation in scattered light intensity (on the Z axis) as a function of increasing alumina particle concentration AI2O3 (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 alumina phase. These 3D Scatter Curves are approximately circular and remain as such with increasing alumina concentration as these films are approximately spherical and homogeneously dispersed particles in the polymer 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-wall finishes, both made of polymer composites.

Quantitative analysis via simplified Mie Scatter Curve [0107] 3D Scatter Curves associated with scattered particle polymer systems allow, according to light scattering models, to perform a quantitative analysis, for example, to estimate the average particle diameter contained in the particles. samples.

To this end, the graph of Figure 11 is shown, which is one of the possible forms of on-screen and real-time 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.

[0109] This estimate is consistent with the traditional off-line characterization performed using the commercial control equipment, in which the median diameter of these particles was measured and 0.58 pm was obtained.

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. The 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 16) 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 (12) [0112] Such parameters are used for the quantitative determination of the average particle diameter of alumina, 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 simplicity, an average behavior was assumed here for all possible systems, which could be represented simply by lines with the same fixed intercept value and equal for all lines of 1.167, a value previously observed in the adjustment of data from Figure 12.

For the determination of the slope of the straight lines fitted and particle size, the graph of Figure 14 is constructed. It shows the variation of the straight lines adjusted to the Normalized Spread Profiles calculated by the Mie model for any medium pair / dispersed phase as a function of the average particle size of the dispersed phase. The slope gives the relation: (13) [0115] Thus, knowing the slope of the experimentally-adjusted straight line measured in real time, it is possible to estimate the mean diameter of the particles dispersed in the medium by applying the inverse ratio of Equation 13, or namely: (14) [0116] 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 common intercept (= 1.167) and inclination dependent on average particle size (Diameter (in pm) = -18.5 * inclination) [0117] Scattered laser light intensity was measured. at angles: B = 4.59 °, C = 5.92 °, D = 7.26 °, E = 8.58 °, F = 9.89 ° and G = 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 15, 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 Dso = 2.38 pm.

Another form of visual presentation is that, also shown in Figure 15, where the experimental points (full black squares) are translated keeping their same reading angles, same inclination and setting the intercept at 1.167 as previously mentioned. This displacement positions the points between the simulated lines (empty circles) that represent the behavior of single 2 pm and 3 pm particles, allowing for rapid visual evaluation.

Degree of Anisotropy [0120] 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.

Through quantitative analysis of light scattering at low angles, it is possible to quantify the degree of orientation of dispersed structures in the polymer matrix, either 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: (15) (16) (17) where q: scatter vector, qx: component x of the scatter vector, qy: component y of the scattering vector, /: luminous intensity, n: particle shrinkage index, λ: laser wavelength, Θ: scattering angle, Ι (θ): scattered intensity at angle Θ, Io: 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 feeding this information back, altering the operating conditions with the intention of restoring the previously stipulated anisotropy degree.

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

Quantitative Analysis of Mono-Oriented Polymeric Films [0125] A second form of bench validation used high density polyethylene (HDPE) and low density linear polyethylene (LLDPE) blending 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 into rolling rolls at different pull levels: 2, 3, 4, 5 and 6 times the initial length. Such a procedure forces the rotation and reorientation of dispersed crystals in the amorphous matrix increasing their degree of crystalline orientation along machine direction (MD) producing single-oriented films called MDO (Machine Direction Oriented Films).

Figure 16 shows a sequence of in-line 3D Scatter Curves with increasing degree of stretching and therefore of the crystalline orientation of such HDPE / LLDPE blend 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 crystalline orientation level, this circular scattering pattern is transformed into an elongated scattering pattern that is all the more characteristic (elongated) in monoriented structures, the larger the size. degree of stretching / 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 morphology of the crystalline phase undergoes reorientation, which becomes more pronounced from the 4X level of stretching. From 4X, the morphology changes little with the additional stretches, ie the degree of orientation reveals asymptotic behavior. The operator of the single orientation blow extrusion line 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 analysis method. 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 polymer blends.

Operating Range of Phototransistors [0130] In order for the 3D Scatter Curves to be quantitatively analyzed, the light intensity level measured by each of the 90 phototransistors must be within the LIN-LSN illumination range defined during said leveling. level being made by homogeneous lighting plate for leveling.

Figure 17 illustrates an example response graph of six (6) phototransistors (12) positioned from C to H of radius 1 (see coding in Figure 7) during obtaining the 3D Spread Curves shown in Figure 16, where solid HDPE / LDPE blend films with different levels of mono orientation are used. Other sets of phototransistors (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.

One way of adjusting the signal of the phototransistors (12) to fall within such reading limits uses the Laser Intensity Control, already 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. For this purpose the polarizing filter is shaken to such a position that most of the signals fall within the limits mentioned.

Effect of scattering orientation [0133] Figure 18 shows the 3D Scattering Curve of a single ethylene polyethylene terephthalate (PET) fiber measured in two perpendicular directions. It 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 i.e. longitudinal pull direction of the fiber. The intense scattering occurs in the direction perpendicular to the longitudinal orientation of the fiber.

Quantitative analysis during the extrusion process [0134] LALLS optical detector equipment (100) was 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 / alumina polymer composite (mean diameter D50 = 2.38 pm) and (ii) a variable morphology from polystyrene / polypropylene (PS / PP) polymer mixtures.

For these assays, transient concentration dispersed phase PS flux was used, with the second phase being pulsed, either particulate alumina or PP polypropylene grains.

The alumina pulse consisted of 0.1 g of a 16.67% by weight solid masterbatch prepared by dissolving PS in chloroform, dispersing the alumina and further evaporating the solvent. PP was added as pellets with a total mass of 0.15 g. The process parameters were kept constant: a constant thread profile with some KB45 chipping 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, while passing through the LALLS optical detector (100) the pulse of alumina particles and of PP, respectively, during PS extrusion. This period of time between the introduction of the pulse into the extruder feed zone and its complete output after passing through the detector positioned at the extruder outlet is known as DTR Dwell Time Distribution.

It is noted that the scattered light intensity is undetectable up to approximately 190s, 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 3D Scatter Curve pattern 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 in all directions present in the scattering cone 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 through the scattered light intensity due to the passage of the second PP phase 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 as a pulse to the extruder feed zone. This pulse is carried by PS flow through the entire 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 Scatter 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 fibrillar geometries. The last dispersed phase fractions leave the extruder after approximately 1200s.

Unlike the results obtained with the alumina 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 alumina particles or particle agglomerates.

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 in the 3D Scatter Curve becomes more intense as the aspect ratio of the particles increases, resulting in a crest when the particles are fibrillar.

[0149] Elongated pattern 3D scattering curves, positioned orthogonally to the Y flow direction, shown in Figure 19 indicate that the dispersed particles of the second PP phase are deformed (elongated) in the flow direction due to the shear imposed during extrusion.

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 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 offline, with sample collection and post-test in the laboratory.

It can also be used to evaluate in real time the degree of orientation and / or stretching of films of polymeric mixtures, such as those produced by extrusion or extrusion-blow.

[0156] The quality control carried out afterwards not only incurs the waiting time 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-delayed and this time may be long enough to produce prohibitive quantities of off-grade material incurring an increase in production cost.

[0157] In-line or real-time measurement provides the result during product production, enabling corrective action immediately without waiting time.

[0158] The present application further comprises the management system for all operations including leveling of all phototransmitters (12), laser beam alignment (70), response collection of all photoelements (12) including center photoelement, conversion of these signals in variables of interest in the characterization of the system with polyphasic material, on-screen presentation of graphs, curves and data of interest and saving of data in txt planilies.

Claims (17)

1) In-line low angle laser light scattering (LALLS) optical detection equipment including laser alignment system (70), laser light source (71), detector plate (10) and darkroom (20) , cooling system (30), tubular connection frame (60, 62), signal conversion box (80), A / D conversion board (90) and computer (95) for running monitoring and control software, said (a) On said detector plate (10) for quantitatively and spatially defined capturing the intensity of laser light emitted by said laser light source (71) and scattered by a sample (51); set of: /) 90 photoelements (12) forming radii numbered from 1 to 9 offset by 33.75 ° (27078) from each other and occupying three quadrants (270 °) and / 7) an additional central photoelement (12) encapsulated in the bottom of a light absorbing well formed by a small hollow stainless steel cylinder (11), plate with pinhole and black plasticine; for said central photoelement (12) being directed, with the aid of the laser alignment system (70), the transmitted and non-scattered laser light beam, additionally said central photoelement (12) 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 homogeneous illumination plate (40) for leveling the response of the photoelements (12), said homogeneous illumination plate (40) emitting homogeneous light above said plate (10) and comprising a set of LEDs (42) arranged side by side positioned on the edge thereof, each LED (42) emitting light divergingly on the side of said plate (40), the light coming from the said LEDs (42) exiting orthogonally at (43) by 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 light beam from the laser light source (71) passes through said controller ( 61) having a luminous intensity fixed to the tubular connecting structure (60, 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 plate (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 joining the alignment system (70) of the laser light source (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 laser beam passes therethrough, and sequential and continuous measurement of moving parts on a conveyor belt is performed. 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). Equipment according to Claim 1, characterized in that the leveling of the signals emitted by the phototransistors (12) comprises discretely varying the light intensity emitted by the LEDs (42) of the homogeneous lighting plate (40) at least 10 pre-intervals. defined by means of the electronic circuitry of the box 80 so as to produce at least 10 levels of variation of light intensity represented by the 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 generating for each phototransistor (12) an array of XY point pairs, said matrix being fitted with an exponential curve of the type XY. Y = a.EXP (bX), the coefficients “a” and “b” being quantified and archived for use during the scattering measurement, and then the measured signal for each phototransistor (12) converted to level signal, and you can compare quantititativamente the signals obtained by the various phototransistors (12). Equipment 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 anisotropy degree. dispersion phase, residence time distribution curve 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 polyphasic material which produces finished products selected from films, fibers, vials 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 average 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 light plate (40) with stepped intensity control in the darkroom (20) and proceeding to the automated leveling cycle 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 phototransistor (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, LIN-LSN; e) subjecting the polymer melt, sample (51), to real-time analysis by low angle laser light scattering, in-line LALLS; f) from the signals sent by the detector plate (10) and the performance of the calculation system to quantify, in real time, the morphology of said polyphasic system through a 3D Scatter Curve, and from this to calculate the anisotropy degree and additionally or alternatively calculate molecular orientation, average 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. A method according to claim 16, characterized in that it comprises the following steps: a) adapting the LALLS optical detector equipment (100) of the invention in 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) to be as small as possible; d) inserting the homogeneous light plate (40) with stepped intensity control in the darkroom (20) and proceeding to the automated leveling cycle 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 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 optical 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 on the computer screen (95) profiles of 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.