FILCO® 621 is an unsaturated polyester resin formulated with ethoxylated BPA in powder form, primarily employed as a binder for Continuous Strand Mat (CSM). It exhibits a light yellow, free-flowing powder appearance. Key product characteristics include slower solubility in styrene compared to propoxylated binders, a strong binding capacity for glass fibers, excellent compatibility with unsaturated polyester matrices, and a glass transition temperature (Tg) of approximately 53°C.

Functions: Resins, Binders & Matrix Materials

Chemical Family: Polyesters

Technical Data Sheet

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Identification & Functionality

Chemical Family
Composite Materials Functions

Features & Benefits

Characteristics of Film
  • Slower solubility in stirene compared with propoxylated binders
  • High binding power for glass fibers
  • High compatibility with unsaturated polyester matrices
  • Tg around 53°C


Physical Form
Light yellow, free flowing powder
Typical Properties
ValueUnitsTest Method / Conditions
Melt Index20g/10 minutesMA109RPL
Glass Transition Temperature (Tg)122°F-
Acid Number20mg KOH/gMA018LCP
Particle Size Distribution
ValueUnitsTest Method / Conditions
Particle Size (>500 μm)0%MA123LFE
Particle Size (>425 μm)max. 0%MA123LFE
Particle Size (>250 μm)27%MA123LFE
Particle Size (>180 μm)25%MA123LFE
Particle Size (>125 μm)20%MA123LFE
Particle Size (>75 μm)14%MA123LFE
Particle Size (>45 μm)10%MA123LFE
Particle Size (Passing Through)4%MA123LFE

Packaging & Availability

Regional Availability
  • Canada
  • Mexico
  • USA

Storage & Handling

Shelf Life
24 months
Storage and Shelf Life Conditions

FILCO® 621 should be stored in closed containers away from direct sun rays, at temperature below +30°C. In these conditions maximum suggested storage time is 24 months from production, in the original package. After that date product must be rechecked.