FILCO® JS 208 is an unsaturated polyester-epoxy resin, available as a non-ionic water dispersion, utilized as a film-former in glass fiber sizings. It boasts several key characteristics, including a narrow distribution of particle sizes, ensuring consistency. The resin offers an extended shelf life due to its resistance to hydrolysis, which is attributed to its fine particle size. Additionally, it exhibits high mechanical shear stability when diluted, contributing to its effectiveness in various applications within the glass fiber industry.

Functions: Film Former

Chemical Family: Epoxy-Polyester Hybrid

Compatible Polymers & Resins: Epoxies (EP), Unsaturated Polyester (UPE)

Technical Data Sheet

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Identification & Functionality

Chemical Family
Composite Materials Functions

Features & Benefits

  • Narrow particle size distribution
  • High shelf life due to hydrolytic resistance and fine particle size
  • High mechanical shear stability of diluted emulsion
Characteristics of Film
  • Clear
  • Not tacky
  • Glass transition temperature Tg=6°C
  • Very quickly soluble in styrene
  • Compatible with unsaturated polyester and epoxy resins

Applications & Uses

Compatible Polymers & Resins
Compatible Reinforcements
Composites End Use
Processing Information

FILCO® JS 208 is suggested as film former for glass fiber sizes for:

  • Roving for translucent sheet


Physical Form
Milky liquid
Typical Properties
ValueUnitsTest Method / Conditions
Solid Content45 - 47%MA145LFE
pH2 - 4-MA148LFE
Epoxy Equivalent Weight (on dry resin)1900 - 2000g/eqMA149LFE
Particle Size Distribution
ValueUnitsTest Method / Conditions
Average Particle Size600 - 1000nmMA147LFE

Packaging & Availability

Regional Availability
  • Canada
  • Mexico
  • USA

Storage & Handling

Shelf Life
8 months
Storage and Shelf Life Conditions

FILCO® JS 208 should be stored in closed containers away from direct sun rays, at temperature between +5 and +30°C. In these conditions maximum suggested storage time is 8 months from production, in the original package. After that date product must be rechecked. During storage a slight settlement can take place, which can easily be eliminated by careful stirring. Prevent from freezing.