Sinepoxy® CER-421 is an Cycloaliphatic Epoxy Resins, equivalent to 2021P, ERL4221, UVR6105, and CY179. It is widely used in electronic insulation,electronic sealing materials and cationic curing systems.
Chemical Name: 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate
CAS No.: 2386-87-0
Molecular Formula:C14H20O4
Molecular Weight:252.31
Molecular Structure:
Sinepoxy® CER-421 is a cycloaliphatic epoxy resin (3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, CAS 2386-87-0), equivalent to Daicel 2021P, Dow ERL-4221, and UVR6105. It offers outstanding UV resistance, thermal stability, low viscosity, and high Tg, making it suitable for a wide range of applications including electrical insulation, LED encapsulation, composites, UV coatings, and cationic curing systems.
SINEPOXY® CER-421 is available in three grades to suit different application requirements and cost targets:
| Parameter | CER-421S (Premium) | CER-421D (Standard) | CER-421C (Economy) |
|---|---|---|---|
| Purity | ≥ 97.0% | ≥ 90.0% | ≥ 90.0% |
| Color (Pt-Co) | ≤ 50 | ≤ 100 | ≤ 150* |
| Viscosity (25°C, cps) | 220 – 250 | 300 – 450 | 300 – 450 |
| Epoxy Equivalent (g/eq) | 126 – 135 | 131 – 143 | 131 – 143 |
| Key Features | High purity, excellent clarity, best for optical and cationic systems | Cost-effective, suitable for most composite and insulating applications | Most economical, ideal for applications where color is not critical |
*Typical value, not a specification.
| Parameter | CER-421S (Premium Electronic grade) | CER-421D (Standard) | CER-421C (Economy) |
|---|---|---|---|
| Appearance | Colorless to light yellow transparent liquid | Light yellow transparent liquid | Yellow transparent liquid |
| Purity (%) | ≥ 97.0 | ≥ 90.0 | ≥ 90.0 |
| Color (Pt-Co) | ≤ 50 | ≤ 100 | ≤ 200 (typical) |
| Viscosity (25°C, cps) | 220 – 250 | 300 – 450 | 300 – 450 |
| Epoxy Equivalent (g/eq) | 126 – 135 | 131 – 143 | 131 – 143 |
| Water (%) | ≤ 0.05 | ≤ 0.05 | ≤ 0.05 |
| Total Chloride (ppm) | ≤ 100 | ≤ 100 | ≤ 100 |
| Specific Gravity (25/25°C) | 1.15 – 1.18 | 1.15 – 1.18 | 1.15 – 1.18 |
Note: This data sheet is intended to give typical results, not a standard. Subject to Certificate of Analysis (COA).
UV curable – high reactivity in cationic photopolymerization
Anhydride curable – suitable for thermal curing systems
High Tg – up to 195°C when cured with anhydrides
Excellent UV resistance & yellowing resistance – ideal for outdoor and optical applications
Outstanding electrical insulation – low dielectric loss, high volume resistivity
Low viscosity – easy processing and compounding
Low halogen – meets environmental requirements
High purity – low ionic impurities
| Application | Recommended Grade | Key Benefit |
|---|---|---|
| LED encapsulation | CER-421S | High clarity, low yellowing |
| Electronic insulation / potting | CER-421D or CER-421C | Good electrical properties, cost-effective |
| Carbon fiber cable cores | CER-421S or CER-421D | High Tg, mechanical strength |
| 3D printing resins | CER-421S | Cationic curability, low shrinkage |
| UV coatings & inks | CER-421S | Fast cure, excellent surface properties |
| Anhydride-cured casting | CER-421D or CER-421C | Same performance as premium grades at lower cost |
| Application / Requirement | Recommended Grade | Reason |
|---|---|---|
| Cationic UV curing (inks, coatings, 3D printing) | CER-421S | High purity ensures consistent cure response and low yellowing |
| Optical / transparent applications (LED encapsulation, optical adhesives) | CER-421S | Low color and high clarity are critical |
| High-performance composites (carbon fiber cable cores, aerospace) | CER-421S or CER-421D | CER-421S for premium, CER-421D for cost-effective |
| Electrical insulation / casting (insulators, potting, transformers) | CER-421D | Meets standard performance requirements at lower cost |
| General composites / FRP | CER-421D | Sufficient purity, excellent value |
| Color-insensitive applications (structural casting, large-volume potting) | CER-421C | Lowest cost, same curing performance as D grade |
Note: All three grades offer essentially the same curing performance when cured with anhydrides. The main differences are purity, color, and viscosity. For applications that do not require high transparency or light color, CER-421D and CER-421C provide a cost-effective alternative without compromising mechanical or thermal properties.
CER-421 is typically used in combination with cationic photoinitiators (for UV curing) or anhydride hardeners (for thermal curing).
UV Curing: Typically 3–10% of cationic photoinitiator (e.g., SINOCURE 6992 / 6976) based on total resin formulation.
Thermal Curing (Anhydride): Typically 80–120 phr of anhydride hardener (e.g., methyl hexahydrophthalic anhydride) with appropriate accelerator.
Optimal dosage should be determined through formulation testing.
200 kg / iron drum
Other packaging available upon request
Store in a dry, clean, well-ventilated warehouse at room temperature.
Keep containers tightly sealed and protected from moisture.
Avoid exposure to light and heat.
Keep away from acidic or alkaline contaminants.
Shelf life: 24 months from date of manufacture in original unopened packaging. Products beyond this period should be evaluated before use.
We offer a variety of options to help you find the right product for your application
Provide formulation optimization support for water-based/solvent-based systems
Full coverage of REACH, FDA, and GB standards
99.8% on-time delivery rate, 10,000-ton production capacity guarantee
