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Case Study

A More Durable Seal Reduces Warranty Claims for a Premium Water Softener Valve Manufacturer


An increase in warranty claims due to a damaged main seal in a water softener valve prompts the company to find a better solution.

A national manufacturer of premium water softener valves had been experiencing an increase in warranty claims from loyal owners. The company — a long-time Minnesota Rubber & Plastics customer — reached out to our engineering team to help them troubleshoot what was behind the warranty claims.

After extensive forensic analysis of the failed parts by engineers and chemists within our Advanced Materials Group, we discovered the culprit to be the water softener valve’s main seal. The seal had an unacceptable propensity to tear under the duress of constant duty cycles and pressure from water with high rust and sediment levels.

Through microscopic inspection, we discovered the problem was due to the material’s insufficient mechanical durability of the seal material. The challenge was to find an existing compound or create a new one that could hold up to the wear-and-tear of thousands of duty cycles in aggressive water.


A custom compound adapted from a medical device proves 44% stronger.

As it turned out, the water softener valve’s seal worked fine under normal conditions. However, its tear resistance was insufficient to withstand high-pressure water containing rust and sediment.

With a better understanding of the application requirements, our Advanced Materials Group conducted numerous mechanical tests to measure the tear resistance of several different materials. In our search for a more robust material, we recommended a custom compound that our lab developed for an implantable medical device. The compound — 912V — was significantly more durable and had a much higher tear strength than the original part. Tests found the medical device compound was 44% stronger than the original material.

Immediately following approval of the new material by the customer, our tooling engineers designed and created new seal rings for in-house testing and validation.


The new compound doubles the life of the main seal.

Extensive testing of the new seal ring at the customer’s facility proved the new compound — 912V performed significantly better than the original material. Testing found 912V performed over twice as many duty cycles compared to all other materials the customer tested. With these encouraging results, our customer approved the new seal for production. The new compound significantly reduced the number of main seal warranty claims the manufacturer received.

Physical properties912V560AL (Original)
Hardness (ASTM D 2240), Shore A7070
Tensile Strength (ASTM D412), MPa (psi)15.2 (2,200)15.2 (2,200)
Elongation (ASTM D412), %350175
Modulus @ 100% Elongation (ASTM D412), MPa (psi)4.3 (625)6.0 (875)
Tear Strength (ASTM D624, Die C), kN/m (ppi)22.8 (130)15.8 (90)

What Made a Difference

Engineering access

Unlike firms with layers of “gatekeepers,” the
water softener valve manufacturer had direct access to our team of technical specialists, which streamlines processes and improves outcomes.

Time and cost savings

Broad knowledge in multiple industries
led to leveraging a custom compound designed for another application, saving time and cost.

Multi-discipline technical team

A team of material engineers, chemists and tooling engineers working in a well-equipped materials lab were able to lead this project through design, testing
and manufacturing.

Since 1945, Minnesota Rubber and Plastics has built a worldwide reputation as a leader in advanced technologies.

Contact Us

It is a global solutions provider in the development and launch of complex products, from high-tolerance medical components and assemblies to final sterile packaged devices for the most demanding applications using medical-grade elastomers, and thermoplastics.

The company’s reputation is founded on its unique science-based approach that has made it a preferred manufacturing partner for industry leaders in North America, Europe, and Asia. It is well known for its ability to provide cost-effective solutions to technically demanding applications.

Minnesota Rubber and Plastics’ experience in advanced material formulation enables it to be compliant with FDA, EC 1935/2004, NSF 61, and NSF 51, plus ISO 10993 and ISO 13485, to meet your unique product requirements. Its 70-year-plus history in the design and manufacture of complex devices makes it the preferred partner for industry leaders throughout the world.