What are different materials of syringe plunger piston?

Syringe plunger piston is usually made from rubber material or medical grade PVC or TPE material. Rubber materials include natural rubber, isoprene rubber, silicone rubber and butyl rubber. What are features of different materials for syringe plunger stopper as sealing part?

Natural Rubber and Isoprene Rubber Syringe Piston

As compression moulded rubber products by vulcanization, natural rubber and isprene rubber are both common raw mateirals for manufacturing piston for hypodermic disposable syringes. Considering latex percentage of raw material, isoprene rubber will be more user-friendly for patients who are allergic to latex because natural rubber material contains high percentage of latex.

Butyl Rubber Syringe Piston

Butyl rubber is an ideal material to manufacture rubber plunger piston for prefilled syringe compared with other rubber material.

The main component of butyl rubber is polyisobutylene, which contains a methyl group with a large steric barrier, so the thermal movement of the molecule is not active, thus the gas transmission rate is the smallest among synthetic rubber, and the amount of molecular double bond in the main chain is pretty small, so it is good in performance of UV resistance, ozone resistance, weather resistance and heat resistance. Also butyl rubber is non-polar, which means it has good resistance to polar solvents, giving medicines good chemical stability.

For prefilled syringe, medication fluid needs to interact with syringe plunger stopper for a long time, so stability of chemical and biological performance of syringe stopper is critical, this allows butyl rubber an idear mateiral for prefilled syringe plunger stopper.

Becuase of excellent chemical and biological performance of material, buytl rubber is also commonly used in infusion as rubber injection stopper for iv infusion bags.

Silicone Rubber Syringe Piston

Silicone rubber can be used to manfuacture rubber piston for syringe as well. With performance of good adsorption, heat resistence, insoluable in water and stable chemical performance, silicone rubber is commonly used in advanced syringes like low resistance syringe, high-pressure syringe, etc.

TPE Material Syringe Piston

TPE, the abbreviation of thermoplastic elastomers, is a material which combines features of rubber and plastic. Specifically, TPE material will show the high elasticity of rubber at room temperature, and can be plasticized like plastic at high temperature. TPE syringe piston is injection moulded products which needs less time, easier procedures, less complex machine and lower cost to manufacture compared with compression moulded products. Meanwhile, TPE material itself can be recycled, making it outstand other similar material considering environmental protection.

PVC Material Syringe Piston

PVC, the abberviation of Polyvinyl Chloride. Medical grade PVC is commonly used in manufacturing components of medical disposables and equipment. PVC syringe piston is injection moulded products similar to TPE material, also with good performance of chemical resistence, corrosion resistence and ozone resistence. Additionally, cost of pvc material is even lower than TPE material because of better availability.

What are differences between syringe piston made from different materials?

Natural Rubber Syringe Plunger Piston(NR) VS Isoprene Syringe Plunger Piston(IR)

• Natural rubber one contains latex, while isoprene rubber not, which is important performance for patients who are allergic to latex.
• Isoprene rubber will have better performance in elasticity, water resistance, electrical insulation and aging resistance.
• Natural rubber will have better performance in breaking strength rate as well as hardness and compression deformation rate.
• Isoprene rubber will be more expensive than natural rubber.

Isoprene Syringe Piston(IR) VS Butyl Syringe Piston(IIR)

• Isoprene rubber is usually used for ordinary syringe, butyl rubber(IIR) is usually used for prefilled syringe.
• Butyl rubber(IIR) will have better performance in heat resistence, aging resistence, air permeability and chemical resistence.
• Isoprene rubber have be better in elasticity.
• Butyl rubber(IIR) will be in higher price than isoprene rubber.

TPE Syringe Plunger Piston VS Rubber Syringe Plunger Piston

• TPE can be injection mouled, but rubber should be vulcanized. Manufacturing process of tpe gasket will be much easier.
• TPE can be recycled, but rubber cannot be recycled in most cases. TPE will be more environmental friendly.
• TPE has better performance of low temperature resistence, while rubber material has better performance of high temperature resistence.
• Rubber material piston will have much better performance in tensile strength, rebound effect and tear resistence, which are critical performances for syringe plunger stopper.
• Rubber syringe piston will have much better aging performance than TPE material syringe gasket, which means TPE syringe gasket will be more likely to come across air leakage and liquid leakage, thus sealing performance cannot be ensured.

PVC Syringe Plunger Piston VS Rubber Syringe Plunger Piston

• Medical grade pvc syringe piston will be much easier to manufacture by injection mould.
• Medical grade pvc will be cheaper than common rubber material for syringe gasket like isoprene rubber, butyl rubber and silicone rubber.
• Rubber syringe piston will be much better in water resistence, oil resistence, elasticity.
• Rubber syringe piston has better performance in tensile strength, rebound effect and tear resistence, while pvc syringe gasket will deform or expand or shrink more easily.
• Rubber syringe piston will have better aging performance than PVC syringe gasket.

To summarize, characteristics of different materials for manufacturing syringe plunger piston differ from each other,  all materials have pros and cons from different perspective. To choose an idear material, it would be better to comprehensively consider all aspects like performance, cost and application.