Iowa Paint Manufacturing Co. Viscosity Analysis

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Iowa Paint Manufacturing Co.Viscosity Analysis

• Presented By
• Ruchi Patnaik
• Co-Author
• Piyanka Roy

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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

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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

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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

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Viscosity

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

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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

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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

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Analysis

• Gage RR study for lab measurement precision
• Homogeneity test for within vat sampling variance
• Regression Analysis

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Gage RR

• 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

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Gage RR

• 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

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Gage RR Data
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RR 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
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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

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Within-Vat Data
Operator
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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 2.3
50 0.196 MSAB Error 20 7.500 0.375 MSE Tota
l 39 40.975
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Results of Measurement Precision Studies

• Gage RR Calculations
• ?repeatability 0.250 Krebs
• ?reproducibility 0.327 Krebs
• To combat reproducibility variation, keep
  operator fixed

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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

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Historical Data
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Historical Data

• Plot of all nine samples in order to examine the
  slope

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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

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

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Viscosity Table
Table for the amount of additive appropriate for
various tank sizes
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Viscosity Plot
Plot of viscosity increase versus A44 addition
for the 1000-gallon tank
Viscosity Increase (Krebs)
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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

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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)

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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

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Acknowledgements

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

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Questions?