Buying silicone sheeting and uncured compound might seem like a low-risk activity, even when you’re purchasing spec-grade materials. A silicone that’s “qualified” meets mechanical, chemical and regulatory requirements and can remain in the same bill of materials (BOM) for years. In an age of global sourcing, however, believing that a compound won’t change is risky.
Silicone Compounds and Silicone Ingredients
Silicone compounds contain numerous ingredients. Examples include fillers, colorants, and flame retardants – just to name a few. Changing one key ingredient can affect an entire compound’s mechanical properties, thermal stability, compression set, and cure profile. Ingredient substitution can also negate a compound’s compliance with a standard or regulation.
Even if you’re buying domestically manufactured silicones, those compounds probably contain ingredients that come from nations where there’s a risk of a supply chain shut-off. If a key ingredient suddenly becomes unavailable, your compounder will look for another source. Failure to find a replacement isn’t the only threat to your supply chain, however.
This article from ElastaPro examines the risks and costs associated with silicone requalification, a lengthy and expensive process that could become necessary because of ingredients. As you continue reading, remember that supply chain resilience isn’t just about where a silicone compound is made. It’s also about where its ingredients come from.
Medical Silicone Example
Imagine that you’ve been buying a U.S.-made medical grade silicone that contains a key ingredient from a nation with which the United States has serious disputes. The ingredient suddenly becomes unavailable because of a geopolitical disruption, a trade war, or because of a plant shutdown caused by a personnel issue.
The compounder substitutes a chemically similar ingredient and tells you that the new material is equivalent. There’s a problem, however. Medical-grade silicones must comply with standards such as ISO 10993, USP Class VI, and FDA 21 CFR 177.2600. Because of the substitution, there’s a risk that the compound that you’ve been buying is no longer biocompatible.
The way to address this risk isn’t by reviewing your supplier’s internal testing data. You’ll need to requalify the entire compound, a process that’s especially demanding in regulated industries like medical device manufacturing. In addition to mechanical and physical testing, there’s chemical, analytical, and standards-specific testing to perform.
Depending on the medical device’s class, you may need to update FDA Master File references, the Design History File (DHF), and the Device Master Record (DMR). There’s also risk management documentation to compile and supplier qualification records to review.
Military Silicone Example
Military silicones offer another example of where an ingredient substitution can put projects, your business, and potentially national security at risk. Imagine that you’re a buyer for a defense contractor that needs A-A-59588 silicones. More specifically, you need a Class 3B silicone. You find a vendor that supplies this material and offers a Certificate of Conformance (COC).
That type of cert is useful, but it simply states that a product meets standards or specifications. In other words, it doesn’t contain test-level data for your specific batch of materials. This is a problem because, at some point, the supplier made an ingredient substitution that reduced the compound’s flex resistance or heat age so that it no longer meets A-A-59588 Class 3B requirements.
When the compound fails during testing, you raise the issue with your supplier. That’s when you learn that the compounder had switched sources for a key ingredient. The new ingredient was less expensive, but the supplier is located in a country that’s not authorized to supply U.S. defense projects. The status of your project just went from bad to worse.
How to Reduce Costs and Risks
Silicone compounders that buy ingredients from risky sources can put more than just your supply chain at risk. In the medical, food processing, aerospace, and defense industries, it’s critical to use compounds that meet industry standards or regulatory requirements. And buying a “cheap silicone” won’t prevent you from having to pay for expenses like requalification.
At ElastaPro, we work closely with buyers so that they understand not just what they’re specifying, but where it comes from and how secure that supply chain really is. We also provide a full Certificate of Analysis (COA) with every batch and welcome your questions about the origins of our raw materials, which come from friendly sources rather than risky ones.
