FILCO® 309 represents an epoxy resin formulated in a non-ionic water emulsion, specifically designed as a film-former within glass fiber sizings. Its appearance is that of a milky liquid, while its defining product characteristics include pure epoxy resin composition, a narrow particle size distribution, stability against hydrolysis and sedimentation, and remarkable mechanical shear stability even in diluted emulsions.

Functions: Film Former

Chemical Family: Epoxy & Epoxy Derivatives

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

Processing Methods: Filament Winding, Pultrusion

Technical Data Sheet

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Identification & Functionality

Composite Materials Functions

Features & Benefits

  • Pure epoxy resin
  • Epoxy equivalent around 280 g/eq
  • Narrow particle size distribution
  • Hydrolysis and sedimentation stability from pH 2 to 12: min 48 hours
  • High mechanical shear stability of the diluted emulsion
Characteristics of Film
  • Clear
  • Tacky
  • Compatible with unsaturated polyester, epoxy, phenolic matrices
  • Quickly soluble in styrene

Applications & Uses

Compatible Reinforcements
Composites Processing Methods
Processing Information

FILCO® 309 is suggested as film former for glass fiber sizes for:

  • Filament winding roving
  • Pultrusion roving
  • Weaving roving


Physical Form
Milky liquid
Typical Properties
ValueUnitsTest Method / Conditions
Viscosity (at 25°C, #3, 20rpm)1500 - 2500mPa.sMA143LFE
Solid Content52 - 56%MA145LFE
pH (at 20°C)6 - 7.5-MA148LFE
Epoxy Equivalent Weight (on dry resin)260 - 310gMA149LFE
Particle Size Distribution
ValueUnitsTest Method / Conditions
Average Particle Size200 - 700nmMA147LFE

Packaging & Availability

Regional Availability
  • Canada
  • Mexico
  • USA

Storage & Handling

Shelf Life
12 months
Storage and Shelf Life Conditions

FILCO® 309 should be stored in closed containers away from direct sun rays, at temperature between +15 and +35°C. In these conditions maximum suggested storage time is 12 months from production, in the original package. After that date product must be rechecked. Like all low-molecular-weight epoxies, FILCO® 309 can have formation of Crystals at temperatures below 15°C; in case it happens, product should be re-conditioned by mixing and stirring, following coim adivice.Prevent from freezing – thoroughly mix before use