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High Temp. Release Film



Super-heat resistant polyimide film produced from UBE’s exclusive “BPDA (Biphenyl tetracarboxylic dianhydride)“ monomers.
This formulation is unique to UBE and exhibits outstanding dimensional stability, low water absorption and very high chemical resistance.


Compared to other polyimide films, Upilex®-S has better surface smoothness and higher chemical resistance, greater stiffness and much higher heat resistance. Outgassing is very low, so it is easy to use.

(1) Mechanical properties
“UPILEX®-S” delivers outstanding mechanical characteristics across a wide temperature range. It also demonstrates high tensile strength and modulus, and even features outstanding long-term heat resistance. Another exceptional feature of “UPILEX®-S” is its high resistance to hydrolysis, as demonstrated by its properties being virtually unaffected even when it is immersed in boiling water for long periods of time.

(2) Electrical properties
“UPILEX®-S” exhibits excellent electrical characteristics over a wide range of temperatures and frequencies. Even at hightemperatures, “UPILEX®-S” shows almost no deterioration in its electrical properties, unlike other plastic-type films. It also displays a low level of electrical insulation defects, making it an optimal choice for electrical and electronic uses thatdemand high reliability.

(3) Thermal properties
“UPILEX®-S” boasts the highest heat resistance of any plastic film currently available. Its major features include a high  starting temperature for thermal decomposition, smaller values for both heat shrinkage and thermal linear expansion  coefficients, as well as flame resistance (UL94 VTM-0). Therefore, “UPILEX®-S” changes little in size even when heated.
This makes it ideal for use in FPC and TAB-tape substrates composed of minute circuits.

(4) Chemical-resistant properties
“UPILEX®-S” is insoluble in all organic solvents and is sufficiently resistant to virtually all chemicals, including inorganic acid and alkali solutions. This chemical resistance provides exceptional physical properties as well as superior dimensional stability when “UPILEX®-S” is exposed to chemicals. As resistance to various automotive oils (engine oil, brake oil, gasoline, etc.) is strong, it is suitable for use in many automotive applications.

(5) Smooth surface
“UPILEX®-S” has a excellent smooth surface with low roughness. Therefore, it can also be suitably used as a film carrier base for other high heat resistance resins, cushioning materials or releasing materials.

Releasing material Application Example


Since outgassing is very low compared to general polyimide, it is the perfect film for many applications with vacuum and/or high-temperature processing.
Resin coats formed from a carrier base of “UPILEX®-S” have moderate adhesion strength to peel off later
and offer a very smooth surface.