Refrigerator Water Filter and Cap – Case Study

At PolySource, we pride ourselves on the technical problem-solving abilities of our consultants in the field. We consistently aim to provide the best solutions for our customers, which is why our field experts are trained at every level of plastic program development. To showcase this expertise, we’ve provided several case studies that emphasize the PolySource advantage. We’re not just your average plastic resin distribution company, we are your partner in delivering technical solutions that your business benefits from.

Large Filtration OEM

Before PolySource

OEM had selected and was using an unfilled PP material for consumer refrigerator water filters.


  • OEM was experiencing field failures with their refrigerator water filters leaking.
  • Several customers returned the faulty water filters.
  • OEM discovered that due to temperature changes within the refrigerator, the filter experienced expansion and contraction causing the leaking water.
  • The design was fixed resulting in the need for a new material.Increasing elongation created concern on maintaining the required stiffness

Application Requirements

  • The filter housing and end cap needed to withstand the expansion & contraction during temperature changes.
  • OEM developed ‘Freeze/Thaw’ testing to simulate conditions and the part/material needed to pass the test.
  • In addition to being able to elongate to withstand expansion and contraction, the end cap until also needed to retain enough stiffness to meet performance expectations.
  • PolySource developed two customized formulations for both the filter housing and end cap.

PolySource Solution


  • PolySource Integra custom materials were designed to meet the stiffness, impact and elongation needs of the filter housing and end cap.
  • Both materials comply with regulatory approvals and passed the ‘Freeze/Thaw’ test that the OEM required.

Advantages of New Material

  • Eliminated concerns of field failures, potential customer returns and warranty issues for the OEM.

Bottom Line

By starting at the beginning, and understanding “ALL” the complex mechanical property needs and CTQs, including temperature cycling of the applications, material candidates can be formulated, tested and approved. PolySource developed a customized material solution to meet all the customer’s CTQs and eliminate costly recalls.