Iowa Paint Manufacturing Co. Viscosity Analysis

1. Iowa Paint Manufacturing Co.Viscosity Analysis Presented By: Ruchi Patnaik Co-Author: Piyanka Roy

2. Iowa Paint Manufacturing Co. • Since 1933, Iowa Paint has been making quality paint and coatings • More than 1400 colors available • The choice of professional painting contractors for quality paints • Paints and coatings meet and/or exceed U.S.Government paint specifications

3. Satin Acrylic House Paint • Very durable for interior walls and ceilings • Good color retention • Easy water clean-up • Low odor • Dries to tough finish • Rooms can be used almost immediately

4. Objective • Improve viscosity for batches of paint • Determine precision of viscosity measurements (and identify removable sources of imprecision) • Find the appropriate quantity of Hydroxyethyl Cellulose (HEC also known as A44) to be added for various desired adjustments of viscosity

5. Viscosity • Viscosity of paint is increased or decreased by addition or removal of the following three elements • A44 (Hydroxyethyl cellulose) • T49 (Water) • Resin

6. Current Situation • Low initial incoming viscosity • Final viscosity requirement: 95-100 Krebs • Use of A44 to increase viscosity • Paint produced in 2000 or 4000 gallon tanks • Use of trial and error to get to desired viscosity

7. Why A44? • High thickness efficiency • Low water solubility • Excellent color development and color acceptance • Compatibility with a broad range of paint ingredients • Batch-to-batch uniformity • Good brush and roller application • Non-sagging properties

8. Analysis • Gage R&R study for lab measurement precision • Homogeneity test for within vat sampling variance • Regression Analysis

9. Gage R&R • Repeatability is variation typical of that seen in repeat measurements for a particular operator on a particular specimen • Reproducibility is variation that can be attributed to differences between operators

10. Gage R&R • Two different batches of paint • Two measurements by each of 4 group members for each batch • Use of viscometer and stop watch to measure viscosity • Viscosity measured at 77Fahrenheit

11. Gage R&R Data

12. R&R Calculations ^ ^ Equations for repeatability and reproducibility: Source DF SS MS Parts 1 52.5625 52.5625 MSA Operators 3 0.6875 0.2292 MSB Interactions 3 0.6875 0.2292 MSAB Error 8 0.5000 0.0625 MSE Total 15 54.4375 I (parts) = 2 J (Operators) = 4 m = 2

13. Within-Vat Sampling • Five samples from one batch of paint • Two measurements by each of 4 group members for every sample • Use of viscometer and stop watch to measure viscosity • Viscosity measured at 77° Fahrenheit

14. Within-Vat Data Operator

15. Within-vat Calculations ^ Equations for locations: Source DF SS MS Locations 4 30.850 7.713 MSA Operator 3 0.275 0.092 MSB Interaction 12 2.350 0.196 MSAB Error 20 7.500 0.375 MSE Total 39 40.975

16. Results of Measurement Precision Studies • Gage R&R Calculations • repeatability = 0.250 Krebs • reproducibility = 0.327 Krebs • To combat reproducibility variation, keep operator fixed ^ ^

17. Results of Measurement Precision Studies Within-Vat Calculations • repeatability = 0.612 Krebs • locations = 0.922 Krebs To account for location variation, sample from several locations and either physically mix, or average measurements ^ ^

18. Historical Data

19. Historical Data • Plot of all nine samples in order to examine the slope

20. Regression Analysis • Use of Minitab software to find relationship between amount of A44 added and mean viscosity increase • Equation found is in terms of: • Add ‘x’ pounds of A44 in every 1000 gallons of paint to increase viscosity by ‘y’ Krebs • Minitab output for regression analysis gave 1.19 lbs. of A44 additive to be added to 1000 gallon tank for 1 Kreb increase

21. Regression Output The regression equation is: visc = 87.3 + 1.19added + 5.51 z1 + 5.01 z2 + 6.25 z3 + 3.51 z4 - 2.21 z5 + 1.38 z6 - 0.21 z7 + 0.77 z8

22. Derived Equations Equations were derived for each size of tank used by Iowa Paint, where y = pounds of A44 & x = desired viscosity increase (Krebs) • For 1000-gallon tank: y = 1.19 * x • For 2000-gallon tank: y = 1.19 * 2x • For 3000-gallon tank: y = 1.19 * 3x • For 4000-gallon tank: y = 1.19 * 4x

23. Viscosity Table Table for the amount of additive appropriate for various tank sizes

24. Viscosity Plot Plot of viscosity increase versus A44 addition for the 1000-gallon tank Viscosity Increase (Krebs)

25. Conclusions • Several factors play a role in viscosity measurements • One source of variation relates to measurements done by different people • Another relates to tank location of the sample obtained • Historical data provides quantitative guidance for viscosity adjustment

26. Recommendations • Make sure that only one person handles the viscosity measurement • Samples for measurement of viscosity may be taken from different areas of paint tank and mixed or measurements averaged • Use the equations, table and chart derived from historical data to eliminate trial and error (and get correct viscosity)

27. Aftermath • Company is willing to try it out! • Able to give the company an acceptable solution to implement • Derived accurate amounts of Hydroxyethyl Cellulose to add to achieve desired viscosity level • Graphical and tabular representation of solution for easy reference

28. Acknowledgements • Dr. Stephen Vardeman Professor Iowa State University • Mr. Mark Angerer Technical Director Iowa Paint Manufacturing Co.

29. Questions?