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

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

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

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

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

Current Situation Low initial incoming viscosity Final viscosity requirement: 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

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

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

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

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

Gage R&R Data

R&R Calculations Equations for  repeatability and  reproducibility : ^^ SourceDFSSMS Parts MSA Operators MSB Interactions MSAB Error MSE Total I (parts) = 2J (Operators) = 4m = 2

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

Within-Vat Data Operator

Within-vat Calculations Equations for  locations : ^ SourceDFSSMS Locations MSA Operator MSB Interaction MSAB Error MSE Total

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

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

Historical Data

Plot of all nine samples in order to examine the slope

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

Regression Output The regression equation is: visc = added z z z z z z z z8

Derived Equations 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 Equations were derived for each size of tank used by Iowa Paint, where y = pounds of A44 & x = desired viscosity increase (Krebs)

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

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

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

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)

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

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

Questions?