DOWSIL ME-4039
Harmonization Code : 3910.00.00.90 | Silicones in Primary Forms; Others
Main features
- Transparent Addition-Cure Silicone Encapsulant
- 91.5% Transmission at 450 Nm
- 26-Minute 125 deg C Cure
Product Description
DOWSIL ME-4039 Encapsulant Clear Kit is a transparent, two-part addition-cure silicone for die coating and wire-bond packaging in micro- and optoelectronic assemblies. It combines clear optical performance with low ionic impurity levels and is documented for LED, optocoupler, and MEMS applications. Typical optical data includes 91.5% transmission at 450 nm through 1 mm and refractive index 1.41. Part A viscosity is 5.4 Pa-s, Part B is 2.1 Pa-s, and a documented heat-cure schedule is 26 minutes at 125 deg C.
Key features
- Optical performance:: Transparent addition-cure silicone with 91.5% transmission at 450 nm through 1 mm.
- Key characteristic: Low ionic impurity values of 0.6 ppm Na+ and 0.4 ppm K+.
- Processing window:: Heat cure time of 26 minutes at 125 C with Part A and Part B viscosities of 5.4 and 2.1 Pa-s.
Applications
- LED packaging
- Optocouplers
- MEMS
Technical Specifications
General Properties
Additional Information
Potting, Encapsulants & Underfills
Transparent addition-cure silicone for die coating and wire-bond packaging
DOWSIL ME-4039 Encapsulant Clear Kit is a two-part, transparent silicone encapsulant for microelectronics die coating and wire-bond packaging. It is used for LED, optocoupler and MEMS applications and combines low ionic impurity levels, clear optical performance, addition-cure chemistry and low-modulus cured behavior.
As-Supplied Properties
Component, optical and purity data
Component viscosities are shown separately. The optical and ionic values are typical product data.
| Property | Typical Value | Condition / State |
|---|---|---|
| Part A viscosity | 5,400 cP (5.4 Pa-s) | As supplied |
| Part B viscosity | 2,125 cP (2.1 Pa-s) | As supplied |
| Specific gravity | 1.03 | Uncured |
| Mix ratio | 1:1 | Part A : Part B |
| Refractive index | 1.41 | Product data |
| Transparency | 91.5% | 450 nm, 1 mm thick |
| Na+ impurity | 0.6 ppm | Product data |
| K+ impurity | 0.4 ppm | Product data |
| Shelf life at 25 deg C | 24 months | As supplied |
These values are typical and are not intended for preparing specifications.
Processing
Meter mixing and heat-accelerated cure
The two-part encapsulant is compatible with conventional meter-mix processing and can be dispensed, printed or liquid injection molded.
- Meter and mix Part A and Part B at the authorized 1:1 ratio.
- Dispense, print or liquid injection mold the mixed encapsulant into the target package geometry.
- Heat cure to develop final properties. The listed heat-cure time is 26 minutes at 125 deg C.
- Confirm cure compatibility with the actual package materials before production use.
Process controls
- Addition cure produces no cure byproducts.
- Use standard forced-air convection ovens or another controlled oven configuration for full cure.
- Evaluate the complete package and material set when selecting the cure profile.
Storage and Handling
Follow the labeled storage condition
Shelf life is listed as 24 months at 25 deg C. Keep the kit within its labeled storage and handling conditions before processing.
- Keep Part A and Part B identified and controlled as separate components before mixing.
- Avoid contamination by materials known to inhibit addition cure.
- Use the product label as the governing storage reference for the supplied kit.
Technical Guidance
Addition-cure compatibility
Certain materials can inhibit the cure of addition-cure silicones. A compatibility check is appropriate when the substrate, flux or adjacent material is uncertain.
Known inhibition risks
Organotin and other organometallic compounds, sulfur-containing materials, unsaturated hydrocarbon plasticizers and some solder flux residues are identified as potential cure inhibitors.
Small-scale compatibility test
When compatibility is uncertain, run a small-scale test. Liquid or uncured material remaining at the interface after the surrounding gel has cured is an indicator of inhibition.
Package-specific evaluation
The product is positioned for die coating and wire-bond packaging. Validate cure, flow and final behavior in the actual LED, optocoupler or MEMS package geometry.
Final-State Properties
Final material and optical properties
These typical values describe the cured material under the product data conditions.
| Property | Typical Value | State / Condition |
|---|---|---|
| Durometer | Shore A 44 | Cured |
| Penetration | 40 (1/10 mm) | Cured |
| Heat cure time | 26 minutes | 125 deg C |
| Transparency | 91.5% | 450 nm, 1 mm thick |
| Refractive index | 1.41 | Optical property |
Hardness can vary with mixing ratio; this page uses the authorized 1:1 product configuration for processing.
Applications
Micro- and optoelectronic package applications
DOWSIL ME-4039 is specifically listed for die coating and wire-bond packaging across optical and sensing device types.
LED packaging
Transparent silicone die coating for LED package designs requiring the listed optical and cure properties.
Optocouplers
Clear encapsulation and die-coating use in optocoupler package architectures.
MEMS
Microelectronics-grade encapsulation for MEMS package applications.
Review package geometry, cure and optical requirements
Krayden can help review DOWSIL ME-4039 component viscosities, 1:1 mixing, heat-cure conditions, optical transmission, ionic impurity levels and addition-cure compatibility for LED, optocoupler or MEMS packaging. Krayden can also help review the documented processing conditions and evaluation criteria before testing.
