FILCO® JS 129 is an epoxy-ester resin that's dispersed in a non-ionic water emulsion, specifically employed as a film-former within glass fiber sizings. Its features include a non-ionic emulsifier integrated into the polymer, ensuring a narrow distribution of particle sizes. Additionally, it boasts an extended shelf life due to its resistance to hydrolysis, which is facilitated by the fine particle size. The resin also exhibits high mechanical shear stability when diluted and maintains stability against both hydrolysis and sedimentation over a broad pH spectrum.

Functions: Film Former

Chemical Family: Epoxy & Epoxy Derivatives, Epoxy Ester, Polyesters, Unsaturated Polyester (UPE)

Compatible Polymers & Resins: Acrylonitrile Butadiene Styrene (ABS), Polybutylene Terephthalate (PBT), Polycarbonates (PC)

Processing Methods: Filament Winding

Technical Data Sheet

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Identification & Functionality

Composite Materials Functions

Features & Benefits

  • Non-ionic emulsifier built in the polymer
  • Narrow particle size distribution
  • Good shelf life owing to hydrolytic resistance and fine particle size
  • High mechanical shear stability of the diluted emulsion
  • Hydrolysis and sedimentation stability in a wide pH range
Characteristics of Film
  • Clear, soft and not tacky
  • Glass transition temperature Tg=10°C
  • High thermal stability
  • Compatible with epoxy and all types of unsaturated polyesters
  • Quickly soluble in styrene

Applications & Uses

Compatible Reinforcements
Composites Processing Methods
Processing Information

FILCO® JS 129 is suggested as film-former for glass fibers for:

  • Roving for translucent seet
  • Filament winding roving
  • Chopped strand for TP matrices (PBT-PC-ABS)


Physical Form
Milky liquid
Typical Properties
ValueUnitsTest Method / Conditions
Solid Content38 - 40%MA145LFE
Viscosity1000 - 3000mPa.sMA143LFE
pH6 - 8-MA148LFE
Epoxy Equivalent Weight (on dry resin)500 - 560g/eqMA149LFE
Particle Size Distribution
ValueUnitsTest Method / Conditions
Average Particle Size200 - 500nmMA147LFE

Packaging & Availability

Regional Availability
  • Canada
  • Mexico
  • USA

Storage & Handling

Shelf Life
12 months
Storage and Shelf Life Conditions

FILCO® JS 129 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 12 months from production, in the original package. After that date product must be rechecked. Prevent from freezing.