Inline Process Control for Continuos Mixing Solutions

Transcription

1 Inline Process Control for Continuos Mixing Solutions Dr. Cristian Oprisoni Bengaluru, September 2018

2 Agenda Background information Rhenowave - inline process control for rubber compounds Influence of Silanization Summary and conclusion 2

3 Background Information

4 Stress [MPa] ML1+4 [MU] Introduction Discontinuous Mixing Processes Mooney-Viscosity Time [min.] Vulcameter Curves Off-line Quality Control Stress-Strain-Curves Strain [%] Cost intensive production 4

5 Introduction Disadvantages of Offline Quality Control In-spec??? Offline Quality Control Not representative approx % (0.01 kg out of 100 kg) Destructive method Time consuming Testing of samples some minutes/ hours after mixing process Not suitable for continuous mixing processes Off-spec 5

6 Introduction Continuous Mixing Processes Filler + Polymer Accelerators Heat Generation! Dosing Filler dispers. Accel. dispers. To best knowledge no inline process control for black rubber compounds so far! 6

7 Introduction Process Control for Polymer Extrusion Optic NIR Raman UV/VIS Overview Spectroscopic Methods* Terahertz Color LIPS Ultrasound Electromagnetic waves are not suitable for black rubber compounds! Dielectric Conductivity Ultrasound Pressure waves Technology known since 1950 Robust sensors For long term high pressure up to 150 C 100 bar Volumetric Non invasive Array technique up to 100 % Very accurate Very fast (< 1s) * T Hochrein, Plastverarbeiter, September 2009, s. 92 7

8 Amplitude A Extrusion Background Information Set Up for Transmission Rubber compound V s = X t Emitter Ultrasonic pulse Receiver A(p) = A 0 e α x n Sensor distance x α = n=1 α n [n] I 0 Time of flight t I(p) Signal generator and analyzer V s x t p A n [n] Velocity of sound Distance Time of flight Pressure Amplitude Attenuation Ingredient Fraction 8

9 Background Information Attenuation Mechanisms α n = α intr. + α diss. + α str. Intrinsic + Dissipative + Scattering Attenuation of the continuous matrix (rubber) Attenuation of small particles (fillers) Attenuation of large particles (flaws) 9

10 Intensity ln I Intensity ln I Intensity ln I Intensity ln I Background Information Ultrasound Measuring Principles Extrusion Extrusion time t Extr. Extrusion time t Extr. Extrusion time t Extr. Extrusion time t Extr. Without Particles Homogeneous Distribution Inhomogeneous Distribution With Flaws 500 µm 10

11 Rhenowave Inline Process Control for Rubber Compounds Components Sensor technology (ultrasound, temp., press.) Hardware box (PCM LAN100 & PC for calculation and connection) Software (signal detecting and calculation) Range and limitations Homogeneity of filler in rubber mixture (relative values) Experimental confirmation for different rubber types (EPDM, NR, BR) Upgrade possibility Rhenogran AP with marker Homogeneity of cross-linking chemicals in rubber mixture (relative values) An inline system that is capable and reliable to detect the quality of black rubber compounds 11

12 ln I [a.u.] Rhenowave Detection of Large Flaws + Scattering Large flaws (> 500 µm) can easily be detected due to the scattering of ultrasonic waves! Patent pending: EP-A

13 ln A [a.u.] Rhenowave Filler Macro-Dispersion Scattering 8 1 min 2 min 4 min 7 min 7 6 NR/N550 Increase of mixing time Reduction of large filler agglomerates (> 10 µm) due to increase of mixing time in an internal mixer can be observed! Patent pending: EP-A

14 ln A [a.u.] Rhenowave Amount of Fillers 10 x = 20 mm T = 110 C phr N phr N phr N phr N550 + Dissipative 7 6 Detection limit 5 Transmitted ultrasound signal allows the determination of filler amount with an accuracy of better than 1 phr in natural rubber compounds! 14

15 ln A [a.u.] Rhenowave Amount of Fillers 10 x = 20 mm T = 110 C phr N phr N phr N phr N550 + Dissipative 7 6 Detection limit 5 Transmitted ultrasound signal allows the determination of filler amount with an accuracy of better than 1 phr in natural rubber compounds! 15

16 Rhenowave Filler Types 30 phr Carbon Black 30 phr of Fillers Chalk Clay Silica CB No filler No differentiation of CB-grades Different fillers can be distinguished 16

17 Rhenowave Filler Types Chalk vis. ~ particle matrix Clay Silica CB The viscoelastic attenuation vis. is a function of the difference between the density of the hard particle and the density of the viscous matrix. 17

18 Influence of Silanization Experimental

19 Experimental Recipe Ingredient Amount [phr] SBR/BR 100 Oil 40 Carbon Black 35 Silica 55 Anti-Aging 7 Processing aid 2 Stearic acid 1 Silane 5 Zink oxide 2 Accelerator/Retarder 4 Sulfur Recipe Recipe for tire tread compound SBR/BR blend Filler system from carbon black and precipitated silica with silane Sulfur curing system Accelerator: CBS/DPG 19

20 Experimental Testing with Rhenowave Extrusion parameter Laboratory extruder with one screw Small mixing efficiency Extrusion of about 1 kg of sample Extrusion with 20 rpm (approx. 5 kg/h) Tempering at 100 C for die and extruder Distance between ultrasonic transducers x = 10 mm Feeding of the different compounds from internal mixer 20

21 Mixing of compounds 1 st Stage Mixing Procedure 0'' Ram up Polymers 0'' - 45 '' Ram down 45''-1'20'' Ram up Filler, silane, softener, proc. aids 1'20'' 2' Ram down 2'-2'30'' Ram up Anti-ageing, Stearic acid Typical mixing curve 2'30''-3'30'' 3'30''-4' Sweep 5 Ram down Ram down Dump 21

22 Mixing of compounds 1 st Stage Mixing Procedure Variation of mixing time 4 min. to 8 min. Reduction of rotation to keep temperature constant at 120 C at the sensor Variation of dump temperature 120 C to 180 C 5 min. mixing time Variation of rotation Typical mixing curve 22

23 3 Stages for Mixing of Reference Compounds 1 st Stage 2 nd Stage 3 rd Stage 1 st Stage: Incorporation, dispersion, distribution and silanization of fillers 2 nd Stage: Homogenization 3 rd Stage: Addition of vulcanization additives 23

24 Comparison Samples Ring Extruder and Internal Mixer ML1+4 (100 C) RPA2000 (2 nd Sweep, 1 Hz, 60 C) 24

25 Reference Compounds Comparison Vulcameter Curves 25

26 Mixing of compounds 1 st Stage Mixing Procedure Variation of mixing time 4 min. to 8 min. Reduction of rotation to keep temperature constant at 120 C at the sensor Variation of dump temperature 120 C to 180 C 5 min. mixing time Variation of rotation Typical mixing curve 26

27 Variation of Mixing time Results Reference With increasing mixing efficiency (time) the sliding (1 min.) mean values for relative attenuation coefficient rel. decreases. Dump temp. 120 C After the second stage of mixing rel. decreases strongly. rel. = ln A ref. x ln A 27 Patent pending WO2017/129471

28 Variation of Mixing time RPA2000 (2 nd Sweep, 1 Hz, 60 C) Before Extrusion with Rubicon After Extrusion with Rubicon 28

29 Variation of Mixing time RPA2000 (2 nd Sweep, 1 Hz, 60 C) Before Extrusion with Rubicon After Extrusion with Rubicon 29

30 G' (1%) [kpa] Variation of Mixing time Results G'(1%) G'(100%) G' (100%) [kpa] Smaller values for the storage modulus G at small (1%) and large (100%) strain correspond to smaller values for the mean relative attenuation coefficient rel.. The relative attenuation coefficient rel. reflects the variation of mixing efficiency (time) rel. [1/m] 0 Lower slope at 100% shows most of the filler network is gone Patent pending WO2017/

31 Mixing of compounds 1 st Stage Mixing Procedure Variation of mixing time 4 min. to 8 min. Reduction of rotation to keep temperature constant at 120 C at the sensor Variation of dump temperature 120 C to 180 C 5 min. mixing time Variation of rotation Typical mixing curve 31

32 Variation of Dump Temperature Results Different dump temperature T in internal mixer (increase of rotations) can be separated. The relative attenuation coefficient rel. decreases with increasing out put temperature Extrusion with Rhenowave at 100 C rel. = ln A ref. x ln A 32 Patent pending WO2017/129471

33 Variation of Dump Temperature Results Different out put temperature T in internal mixer (increase of rotations) can be separated. The relative attenuation coefficient rel. decreases with increasing out put temperature The extrusion parameters (T1, T2, p) are constant Extrusion with Rhenowave at 100 C rel. = ln A ref. x ln A 33 Patent pending WO2017/129471

34 Variation of Dump Temperature Results Different dump temperature T in internal mixer (increase of rotations) can be separated. The relative attenuation coefficient rel. decreases with increasing dump temperature The extrusion parameters (T1, T2, p) are constant Extrusion with Rhenowave at 100 C rel. = ln A ref. x ln A 34 Patent pending WO2017/129471

35 Summary and Conclusions

36 Summary Significant facts Silanization changes the surface of the silica particle probably with an effect on the dissipative sound attenuation Dissipative Significant differences in the relative attenuation coefficient rel. have been observed for a tread compound with different mixing parameters (time, rotation) for the in situ silanization of silica. The differences in rel. correlate with dynamic and mechanical values of green compounds and vulcanizates. 36

37 Rhenowave Summary Immediate < 1 s (inline) Representative (volumetric) up to 100% Non-invasive Advantages Robust ultrasonic transducers Determination of Compound Homogeneity Distribution of fillers Detection of impurities (> 500 µm) Dispersion of fillers agglomerates (> 10 µm) Rhenowave has the potential as new inline control for rubber compounds 37

38 Outlook Implementation of Rhenowave for the icom process in LANXESS production sites for bladders in Porto Feliz/Brasil, Little Rock/US and Burzaco/Argentina 38 * operational since 01/2017

39 GENERAL LEGAL DISCLAIMER This information and our technical advice whether verbal, in writing or by way of trials is subject to change without notice and given in good faith but without warranty or guarantee, express or implied, and this also applies where proprietary rights of third parties are involved. Our advice does not release you from the obligation to verify the information currently provided - especially that contained in our safety data and technical information sheets - and to test our products as to their suitability for the intended processes and uses. The application, use and processing of our products and the products manufactured by you on the basis of our technical advice are beyond our control and, therefore, entirely your own responsibility. Our products are sold in accordance with the current version of our General Conditions of Sale and Delivery. Trial Products (Rhenowave ) are sales products at the developmental stage. For this reason, no assurances can be given as to type, conformity, processability, long-term performance characteristics or other production or application parameters. No definitive statements can be made regarding the behavior of the product during processing or use. The purchaser/user uses the product entirely at its own risk without having been given any warranty or guarantee and agrees that we shall not be liable for any damage, of whatever nature, arising out of such use. The marketing and continued supply of this material are not assured and may be discontinued at any time. Unless specified to the contrary, the values given have been established on standardized test specimens. The figures should be regarded as guide values only and not as binding minimum values. Kindly note that the results refer exclusively to the specimens tested. Under certain conditions, the test results established can be affected to a considerable extent by the processing conditions and manufacturing process LANXESS. Rhenowave, LANXESS and the LANXESS Logo are trademarks of LANXESS Deutschland GmbH or its affiliates. All trademarks are registered in many countries in the world. 39

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