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Testimonial: pH, Conductivity Measurements in Paints

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Using SevenExcellence, InLab Sensors to Overcome pH Measurement Challenges

Parul Chhaparia
Parul Chhaparia
Joanna Cai
Joanna Cai

Paints are a ubiquitous part of modern life, from the clothes we wear to the cars we drive. However, getting the perfect color and consistency in paint requires precise pH and conductivity measurements. The pH values affect everything from color, viscosity, and adhesion to the durability of the paints. Therefore, measuring accurate pH and conductivity is a key process in ensuring product quality for manufacturers.

This case study follows one of the leading global chemical companies, BASF’s paint production site in China – BASF Shanghai Coatings – as they tackled challenges like inconsistent pH readings and limited bench space. It also demonstrates how they improved the quality of their results with the help of METTLER TOLEDO solutions.

 

Figure 1. BASF Shanghai Coatings site.
Figure 1. BASF Shanghai Coatings site.

Company

BASF is one of the largest chemical producers in the world. The company operates into six segments, including chemicals, materials, industrial solutions, surface technologies, nutrition and care, and agricultural solutions. With production sites in over 80 countries and more than 100,000 employees worldwide, the company focuses on developing innovative processes, technologies, and products for a sustainable future. BASF Shanghai Coatings is one of the major production sites of BASF outside of Germany.
 

Challenges

Low-limit detection in paint production refers to the minimum pH value that can be reliably and accurately detected by the pH meter. This value depends greatly on the accuracy and quality of the instruments, including the meter and electrodes.

BASF Shanghai Coatings’ pH system posed a challenge in achieving the required low-limit detection values, which is crucial to meeting the overall quality in production.

Accurate low-detected values of pH measurement in paint production are essential to ensuring proper formulation and stability of the paint product. Even slight variations in pH can affect the overall performance.

Similarly, the accuracy of conductivity measurements is critical in the electrophoretic coating process. Maintaining the correct conductivity index in the electrophoretic paint bath is necessary to prevent potential risks of poor dispersion performance, reduced break-down voltage, and poor appearance of the paint film.

The production unit also used two separate meters for its pH and conductivity measurements, adding to the challenge of limited bench space in its labs. They urgently needed an all-in-one meter to measure multiple parameters reliably and save bench space at the same time.

 

Solution

The new product unit required sensors with an accuracy of 0.01 µS/cm, which the previous systems could not deliver. To address these challenges, the company reached out to METTLER TOLEDO.

BASF Shanghai Coatings needed to save bench space without compromising the accuracy of its measurement results. Thus, the METTLER TOLEDO team recommended the high-precision, dual-channel SevenExcellence S470K pH and conductivity benchtop meter.

This meter not only measures multiple parameters, but it also offers password protection, user management, programs SOPs into methods, and data transfer via PC, printer, or USB stick. It also supports GLP (Good Laboratory Practice) and 21 CFR Part 11 compliance, making it an ideal choice for the paint production process.

The meter comes with a memory size of up to 250 analyses or 20,000 data points. It is a multi-module meter that can be easily expanded by simply adding a new parameter. For BASF Shanghai Coatings, limited bench space was a major concern. With the SevenExcellence S470K, they can now measure two parameters simultaneously, increasing efficiency and significantly saving much-needed bench space.

 

Figure 2. Accurate pH and conductivity measurements are essential to meet quality requirements in paint production.
Figure 2. Accurate pH and conductivity measurements are essential to meet quality requirements in paint production.

The meter can also be integrated with the InMotion Autosampler and LabX software, making automation and data management efficient for the lab workflows. To address the low-limit detection accuracy, the team recommended the InLab 741 ISM, InLab 731 ISM, and InLab Expert Pro-ISM sensors.

The InLab Expert Pro-ISM sensors are maintenance-free and ideal for pH measurements in paint samples. Its open junction minimizes clogging risks due to the deposition of particulate matter. Additionally, their PEEK (Polyetheretherketone) shaft provides strength and resistance to high temperatures and chemicals, a perfect fit for their requirements.

Similarly, the InLab 731-ISM and InLab 741-ISM are conductivity sensors with Epoxy and Steel shafts designed to resist chemical and mechanical damage, ensuring longevity and accuracy. Moreover, the sensors are available with both 2-pole and 4-pole cells, allowing a broad range of conductivity without compromising accuracy.

Poor adhesion: Inaccurate measurements can also be caused by poor adhesion, leading to peeling or cracking of the paint, reducing its durability and lifespan.

 

Inaccurate pH and conductivity measurements in paint manufacturing can lead to:

  • Inconsistent paint quality: Improper pH and conductivity measurements affect the overall paint quality, causing various issues like color changes, texture, and thickness.
  • Poor adhesion: Inaccurate measurements can also be caused by poor adhesion, leading to peeling or cracking of the paint, reducing its durability and lifespan.
  • Corrosion: Corrosion is another hazard, especially in industrial settings, where harsh chemicals and environments can cause damage.
  • Increased waste and additional cost: Inaccurate measurements can result in off-spec batches of paint, leading to waste and additional costs.
  • Health and safety issues: Paints with incorrect pH and conductivity values may contain harmful chemicals that pose health and safety risks to workers and consumers.

 

Conclusion

The all-in-one SevenExcellence S470K meter proved to be a valuable solution for BASF Shanghai Coatings. It could significantly save and tidy their lab bench space. Following the installation of a pH measurement system comprised of the SevenExcellence meter, InLab Expert Pro-ISM, InLab 731-ISM, and InLab 741-ISM sensors, measurement accuracy significantly improved. These substantial changes have led the company to consider the incorporation of additional SevenExcellence meters in its laboratory.

The company also obtained more reliable results by using the InLab sensors explicitly suited for pH and conductivity measurements of paint samples. The extended life of these robust sensors reduced downtime and overall costs.

The success of the solution is due to its powerful combination of high-quality equipment and prompt service support from METTLER TOLEDO’s team of experts. This provided the customer with the necessary peace of mind.