Material Profile: Engineering EL400 Elastomer Resin for SLA / LCD 3D 列印
Phrozen SLA / LCD Resin Technical Report Series
Compiled from Phrozen official datasheets, SDS documents, and third-party technical reviews
Abstract—Phrozen Engineering EL400 (Gray) is a true rubber-like elastomer with 391% elongation at break, Shore 70–75A hardness, and over 60,000 Ross-flex bending cycles before failure (39.1 kN/m tear strength). It opens entire application areas (gaskets, seals, footwear, custom rubber parts) that are inaccessible to rigid resins and previously required injection-moulded TPU or silicone.
Index Terms—additive manufacturing, SLA, LCD, engineering resin, elastomer, rubber-like, high elongation, tear resistance.
I. MATERIAL IDENTIFICATION
This section establishes the canonical names and commercial designations under which the resin is supplied.
A. Designation
Trade name: Phrozen Engineering Series — EL400 Elastomer Resin. Color: Gray.
B. Resin Family
True elastomeric urethane-acrylate photopolymer; 405 nm UV cure. Cured network behaves as a crosslinked rubber.
C. Aliases and Alternative Designations
|
Alias |
Origin / Usage |
|
EL400 |
Standard engineering-series designation |
|
EL400 Gray Elastomer |
Color variant |
|
Phrozen Engineering Elastomer |
Generic descriptor |
II. COMPOSITION AND PHOTOPOLYMER CHEMISTRY
A. General Resin Family
Generic photo-polymerisation: monomers (multi-functional acrylates / urethane-acrylates) + photoinitiator (e.g., TPO / BAPO) + 405 nm UV → crosslinked thermoset network. Exact formulation is proprietary. Lightly crosslinked elastomeric urethane-acrylate produces rubber-like behavior.
Fig. 1. Photopolymer crosslinking schematic for the resin family.
Fig. 2. SLA / LCD print → wash → post-cure process flow.
B. Composition Breakdown
TABLE I COMPOSITIONAL BREAKDOWN OF ENGINEERING EL400 ELASTOMER RESIN (TYPICAL / PER SUPPLIER DATASHEET)
|
Constituent |
Mass fraction |
Function |
|
Elastomeric urethane-acrylate oligomers + chain-extending diluents |
≈ 70–85 wt% |
Form the backbone of the cured network |
|
Reactive diluents (low-viscosity acrylates) |
≈ 10–20 wt% |
Reduce viscosity; increase crosslink density |
|
Photoinitiator (acylphosphine oxide, e.g., TPO) |
≈ 1–3 wt% |
Absorbs 405 nm UV, initiates radical polymerisation |
|
Pigments, stabilisers, additives |
≈ 1–3 wt% |
Color, UV blocker for shelf life, surface flow |
|
Total |
100 wt% |
— |
III. MECHANICAL PROPERTIES
Elastomers do not have meaningful tensile yield, modulus, or HDT — properties below describe the rubber-like behavior: very high elongation, low modulus, and rebound rather than fracture under load.
TABLE II MECHANICAL PROPERTIES OF ENGINEERING EL400 ELASTOMER RESIN (POST-CURE, ISO 527 / ASTM D638)
|
Property |
Value |
Test method / source |
|
Density |
≈ 1.05–1.12 g/cm³ |
ASTM D792 |
|
Viscosity (uncured liquid) |
≈ 300–500 cP @ 25 °C |
Brookfield viscometer |
|
Shore hardness (Shore A scale) |
≈ Shore A 70–75 (Shore D not applicable) |
ASTM D2240 |
|
Tensile strength, ultimate |
≈ 5–10 MPa |
ASTM D412 |
|
Tensile (Young's) modulus |
≈ 15–30 MPa (very low; elastomer) |
ASTM D412 |
|
Elongation at break |
≈ 380–400 % |
ASTM D412 (Phrozen reports 391%) |
|
Tear strength |
≈ 39.1 kN/m |
ASTM D624 (Die C) |
|
Ross flex (bending) |
> 60,000 cycles before failure |
Ross flex test |
|
Bayshore rebound |
≈ 50–55 % |
ASTM D2632 |
IV. RECOMMENDED PRINT PARAMETERS
Values below are the manufacturer-recommended starting points for compatible Phrozen LCD printers; specific machines may require ±10–20% adjustment based on LCD age and ambient temperature.
TABLE III RECOMMENDED PRINT AND POST-PROCESS PARAMETERS FOR ENGINEERING EL400 ELASTOMER RESIN
|
Parameter |
Value / range |
Notes |
|
UV wavelength |
405 nm |
Standard for Phrozen LCD printers |
|
Compatible printers |
Sonic Mini 8K / 8K S, Sonic Mighty 8K / 12K, Sonic Mega 8K |
Best paired with the indicated resolution class |
|
Layer thickness |
0.025–0.050 mm (typical 0.030 mm) |
Thinner layers improve detail at the cost of print time |
|
Normal exposure (per layer) |
≈ 3.0–4.5 s @ 8K (longer than rigid resins) |
Test-tower validation recommended |
|
Bottom exposure |
≈ 25–35 s × 6 layers |
First-layer adhesion to build plate |
|
Lift distance / speed |
≈ 6–8 mm @ 60–100 mm/min |
Slower for fine geometries |
|
Wash medium |
Isopropyl alcohol (IPA) or 95% ethanol |
30–60 s wash; do not over-soak |
|
Post-cure |
405 nm UV box, 30–60 min (avoid over-cure to preserve elastomer behavior) depending on size |
Phrozen Cure Mega S or equivalent |
V. GLASS TRANSITION TEMPERATURE (TG)
Reported / typical Tg: Not directly applicable (elastomer).
Elastomers do not exhibit a sharp glass transition in the conventional sense; useful service range is approximately -10 to +50 °C.
VI. HEAT DEFLECTION TEMPERATURE (HDT)
HDT defines the temperature at which a 1.27 mm-thick standardised bar deflects 0.25 mm under the specified flexural load. Two test loads are reported per ASTM D648 / ISO 75.
TABLE IV HEAT DEFLECTION TEMPERATURE OF ENGINEERING EL400 ELASTOMER RESIN
|
Test load |
HDT |
Test method / source |
|
0.45 MPa |
Not applicable (elastomer) |
— |
|
1.82 MPa |
Not applicable (elastomer) |
— |
VII. DISTINGUISHING CHARACTERISTICS AND STANDARDS
A. True rubber-like elastomer (391% elongation)
The 391% elongation at break is comparable to thermoplastic polyurethane (TPU) or moulded rubber. Stretches dramatically without breaking.
B. 60,000+ Ross-flex cycles
Demonstrated 60,000+ cycles without failure in Ross-flex bending test (23 °C). Suitable for cyclically-flexed parts (sneakers, gaskets, hoses, vibration mounts).
C. Tear resistance 39.1 kN/m
Among the highest tear-strength values for any SLA elastomer — resists notch propagation, suitable for parts with sharp internal corners.
D. Replaces injection-moulded TPU and silicone
Direct alternative to injection-moulded thermoplastic elastomer or silicone for low-volume / customised parts. Skip the tooling investment.
VIII. REPRESENTATIVE APPLICATIONS
Engineering EL400 Elastomer Resin is typically deployed in the following applications:
1) Custom gaskets and seals: Bespoke cross-section seals for prototyping or end-use small batches.
(Sourse : Phrozen)
2) Footwear midsoles and insoles: Rubber-like cushioning, custom-fit insoles.
3) Vibration-isolation mounts: Rubber-like dampers for sensors, electronics, lab equipment.
4) Bicycle saddle and grip prototypes: Cushioning for sports / cycling components.
5) Robotic gripper soft elements: Compliant gripping surfaces for soft-handling robots.
IX. REFERENCES
[1] Phrozen Technology, “EL400 Resin Product Page,” 2024. Available: https://phrozen3d.com/products/el400-resin
[2] Phrozen Technology, “EL400 SDS,” 2024. Available: https://cdn.shopify.com/s/files/1/0436/6965/1618/files/SDS-Phrozen-Engineering_Series_-_EL400-EN-V2.pdf
[3] ASTM D412-16, “Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers — Tension,” ASTM International.
[4] ASTM D624-00, “Standard Test Method for Tear Strength of Conventional Vulcanized Rubber,” ASTM International.
[5] ASTM D2240-15, “Standard Test Method for Rubber Property — Durometer Hardness,” ASTM International.
[6] ASTM D2632-15, “Standard Test Method for Rubber Property — Resilience by Vertical Rebound,” ASTM International.
(Image Source : Phrozen)