Specialty Silicone Products (SSP) makes bonded caps for clean, pure septa that won’t contaminate your laboratory samples. To ensure analytical purity, SSP uses a proprietary bonding technology to join our platinum-cured silicone septa to polypropylene plastic caps. These screw caps come in a choice of colors and sizes and are available with a single slit for venting during injection.
Platinum-Cured Silicone Septa
Silicones are formed into solid materials through a process called curing. There are two commonly used curing systems: peroxide and platinum. Peroxide curing is less expensive, but it releases byproducts called volatile organic acids (VOAs) that can leach or bleed into laboratory samples. Platinum curing is more expensive, but it does not release byproducts.
SSP makes platinum-cured silicones and fabricates them into septa at our ISO 9001:2015, Made in USA manufacturing facility. Our products include high-purity ultra-low-bleed (ULB) septa for highly sensitive analytical testing. High-purity ULB septa are free from siloxanes, organic compounds that can affect test results from mass spectrometry or chromatography.
Polypropylene Plastic Caps
The polypropylene plastic that SSP uses in its bonded caps is a tough, lightweight material with excellent temperature and chemical resistance. These plastic screw-on caps also feature outer-diameter ribbing so that they’re easier to hold in the hand. Bonded caps come in standard colors that include white, blue, red, and black. They’re available in the following sizes.
- 9 mm screw
- 13-425 screw
- 24-400 screw
- 24-414 screw
SSP supplies caps in bags of 100 or 1000.
PTFE Liners and PFAS-Free Septa Caps
Most of the bonded caps that SSP provides use a PTFE liner for added strength and toughness. Although our current silicone/PTFE septa are technically PFAS-free, PTFE is being lumped in with PFAS, a category of widely used “forever chemicals” that are the subject of state and federal regulations. Therefore, SSP is preparing for a range of regulatory scenarios.
Thanks to the efforts of our in-house research and development team, SSP now offers a PFAS-free septa cap that uses a polypropylene film instead of a PTFE film. Our current offering is a 9 mm screw cap, but additional products are being developed and will be available soon. If you’d like to receive samples of bonded caps, contact us.
