Request an Epoxy Resin Quote: The 8 Inputs We Need for Same-Day Pricing

Same-day pricing for a liquid epoxy resin compound is not a list-price lookup. A Bisphenol A DGEBA resin with an epoxide equivalent weight of 180 g/eq to 190 g/eq and a viscosity of 11,500 mPa·s at 25 °C can be formulated into a clear film or a 65 wt% fused-silica potting compound with raw-material costs that differ by more than 40% per kilogram. The eight inputs below separate formulations that can be priced the same day from those that require reformulation or laboratory screening before a cost is assigned.

The eight inputs are base resin type and EEW, hardener type and AHEW, diluent/additive package, application process, cure schedule and shot mass, volume and package configuration, regulatory compliance, and property test standards.

What Hardener Chemistry and Stoichiometry Must Be Declared?

For a DGEBA liquid resin with an EEW of 182 g/eq, a cycloaliphatic amine hardener with an amine hydrogen equivalent weight of 95 g/eq requires 52 parts by weight per 100 parts resin for stoichiometric cure. An aliphatic polyamine with an AHEW of 60 g/eq requires only 33 parts, but the mixed viscosity is lower and the 100 g gel time at 25 °C may shorten from 38 min to 15 min. Epoxy pricing cannot be separated from hardener stoichiometry because the hardener mass fraction drives raw-material cost, peak exotherm, moisture sensitivity, and post-cure network architecture. The first two same-day inputs are therefore the resin EEW measured by ASTM D1652-11 and the hardener AHEW measured by ASTM D2074-07, together with the intended mix ratio by mass.

For same-day quoting, reactive diluents and solid additives are a third input. Adding 15 phr of butanediol diglycidyl ether to a DGEBA resin reduces viscosity from 11,500 mPa·s to 1,800 mPa·s at 25 °C while suppressing the fully cured glass transition temperature from 72 °C to 44 °C under stoichiometric cure. Loading 60 wt% fused silica with a median particle size of 16 µm raises mixed viscosity to 15,000–30,000 mPa·s and reduces peak exotherm, but the filler must be pre-dried at 110 °C until moisture is below 0.10%. A fumed silica loading of 2.0 wt% can increase low-shear viscosity by 300% and change static mixer pressure loss. Without the exact filler type, particle size distribution, moisture content, and thixotrope level, the quote cannot account for density, shrinkage, thermal conductivity, or metering pressure drop. The fourth input is the complete additive package, including pigment dispersion status and flame retardant synergist concentration.

When Application Method Determines Whether a Quoted System Is Manufacturable

Viscosity and pot-life requirements depend on the selected process. A gravity casting operation using a 500 g shot at 23 °C requires a mixed viscosity below 2,500 mPa·s and a pot life exceeding 20 min, while a vacuum infusion line requires resin viscosity between 200 mPa·s and 500 mPa·s for at least 120 min. A meter-mix dispensing system with a static mixer of 16 to 24 elements can process viscosities up to 80,000 mPa·s, provided the pressure drop remains below 2.0 MPa. The fifth required input is therefore the process boundary condition, stated as viscosity at shear rate, pot life at 100 g mass, or maximum allowable pressure drop. Without this input, a quote may specify a resin that enters a mold but cannot be dispensed through a production static mixer without cavitation or streak defects.

The following process limits are required to prevent underquoting a formulation that passes bench evaluation but fails on production equipment.

When thick-section cure schedules are omitted, the quoted system may be unmanufacturable. The same DGEBA/cycloaliphatic amine formulation cast in a 25 kg block at 23 °C can reach an internal temperature of 190 °C, while a 2 mm film remains below 55 °C. Because exotherm controls thermal stress, voids, and discoloration, the sixth required input is the cure schedule: initial temperature, ramp rate, hold time, post-cure temperature, and largest shot mass. A system cured at 80 °C for 2 h plus 150 °C for 3 h often achieves a glass transition temperature 15–25 °C higher than the same resin cured only at 80 °C for 8 h, as determined by ASTM D3418-15. For thick-section electrical potting, the allowable internal temperature may be capped at 105 °C by adjacent wire insulation, which rules out highly reactive aliphatic amine systems with 100 g gel times below 10 min and large exotherms.

Tensile, Flexural, and Electrical Property Data Inputs for Same-Day Validation

Mechanical and electrical property targets are not default values. A clear casting epoxy may exhibit a tensile strength of 45 MPa and a tensile modulus of 2.1 GPa under ASTM D638-14, while a 65 wt% quartz-filled potting grade reaches 75 MPa flexural strength under ASTM D790-17 and 3.8 GPa flexural modulus. The seventh required input is the set of target properties paired with test method designations, not abbreviated labels. “High strength” carries no data; a valid request states ≥ 60 MPa tensile strength per ASTM D638-14, ≥ 0.8 W/m·K thermal conductivity per ASTM E1530-19, or ≥ 1.0 × 10¹⁴ Ω·cm volume resistivity per ASTM D257-14. Dielectric requirements, such as a dissipation factor below 0.02 at 1 MHz, cannot be priced without the resin-filler system because polar hardeners and absorbed moisture raise dielectric loss. If UL 94 V-0 is required at 3.0 mm thickness, the flame retardant package, usually phosphorus-based or mineral-synergist, changes filler loading and viscosity so substantially that omission prevents same-day pricing.

In high-voltage encapsulation, base resin quality parameters also determine pricing. Hydrolyzable chloride content above 0.01 wt% in liquid epoxy resin can reduce electrical performance and accelerate corrosion in semiconductor encapsulants. For such applications, the quote requires hydrolyzable chloride by ISO 7142:2007, saponifiable chloride, and total ionic contamination. For potting compounds exposed to 85 °C and 85% RH for 168 h, ionic contamination above 5 ppm can reduce volume resistivity below 1.0 × 10¹² Ω·cm. Ultra-low-chloride DGEBA grades with total chlorine below 300 ppm are not interchangeable with general-purpose resins, and their availability affects same-day pricing where low-ionic-content specifications apply. Published data for this specific configuration is limited; when a request includes 85/85 reliability testing, laboratory screening is required before a same-day price can be validated.

On production meter-mix lines, A-side and B-side viscosity imbalance introduces a failure mode that bench testing does not capture. If the A-side viscosity is 25,000 mPa·s and the B-side viscosity is 50 mPa·s, the low-viscosity side may undergo slippage in gear pumps, producing a mix ratio drift of ±3%. This drift changes the network from 95% to 103% stoichiometry, moving the glass transition temperature by 8–12 °C. A quote must specify whether the formulation includes a balancer such as a low-viscosity diluent pre-blended into the hardener side. Without B-side viscosity, the quoted system can pass manual cup mixing but fail on a production meter-mix line.

For production-scale packaging, the eighth required input is volume and package configuration. A quote for 25 kg drums differs from a quote for 400 mL side-by-side cartridges, because cartridges include moisture-barrier foil laminate, static mixer retention, and filling-line shear. Anhydride-cured systems are moisture-sensitive; repackaging under uncontrolled RH above 60% can reduce gel time and increase viscosity. Hazardous material classification for amine hardeners with flash points below 60 °C under IATA/IMDG affects freight cost and same-day dispatch. Destination country and incoterm are part of the packaging input because regulatory documentation and hazardous goods fees are geography-dependent. For production supply, minimum order quantity and blanket release schedule are physical constraints, not commercial negotiation.