Internal Mold Release for Pultrusion

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Key Features

  • Formulated for continuous pultrusion die lubrication
  • Liquid — directly soluble in polyester, vinyl ester, and epoxy resins
  • Reduces pulling force and die wear over extended production runs
  • Minimizes breakouts and line stops from sticking events
  • Does not affect translucency of clear pultrusion profiles

This internal mold release agent is formulated specifically for pultrusion processes where continuous fiber-reinforced profiles are pulled through a heated die. In pultrusion, the resin bath impregnates rovings and mats before entry into the heated die where cure occurs under continuous linear pull. External die release is limited to die entry coatings; internal release in the resin is essential for consistent pulling force and die surface protection across extended production runs. This liquid internal release is soluble in standard polyester, vinyl ester, and epoxy pultrusion resin systems and migrates to the resin–die interface during the cure exotherm inside the die. Dosage 0.5–2.0% by weight on resin. Reduces pulling force, die wear, and sticking events that cause breakouts and line stops. Compatible with the full range of fiber architectures used in pultrusion (roving, mat, woven fabric, unidirectional). Does not affect translucency of clear pultrusion profiles.

Specifications

ParameterValue
FormClear liquid
TypeLiquid internal release (pultrusion grade)
Dosage0.5–2.0% by weight on resin
Shelf Life18 months
Effect on CureMinimal
Compatible ResinsPolyester, vinyl ester, epoxy (pultrusion grade)
Die Temperature Range120–170°C

Applications

Pultrusion of fiberglass structural profiles (I, C, tube, rod)Pultrusion of CFRP profiles for structural applicationsContinuous roving pultrusion (solid rod, bar)Complex pultrusion profiles with tight dimensional tolerancesHigh-speed pultrusion lines requiring consistent low pull force

FAQ

Internal release is added to the resin bath before the pull begins. Mix the liquid internal release into the resin batch using a mechanical stirrer until fully homogeneous (3–5 minutes). For continuous resin bath replenishment systems, add the internal release to the replenishment resin at the same dosage ratio. Maintain the correct dosage consistently — under-dosing leads to increased pulling force and die wear; over-dosing can cause surface defects and reduced fiber-to-resin adhesion.

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