Blue Wearable Smartwatch Sensor Soft Gel Encapsulation

Product Overview:

Hong Ye HY-9405 is a premium two-component addition-cure platinum catalyzed blue jelly gel specifically engineered for low-stress soft encapsulation and sweat-resistant sealing of heart-rate, blood-oxygen sensors and mainboards in smartwatches and fitness bands. With a buttery soft consistency measured at a penetration of 170 plus or minus 30 (0.1mm) and a durably tacky surface, HY-9405 delivers reliable long-life sealing and protection that outlasts conventional gaskets, foams and caulks by a wide margin. The product is mixed 1:1 by weight, self-levels after pouring, cures at room temperature within 4 to 6 hours, and requires no vacuum degassing, making it a straightforward high-performance gel to deploy on production lines worldwide. As a premium anti-yellowing grade, this variant resists UV and thermal yellowing, keeps its clarity and color stable over years of service, and is engineered for long-life outdoor and appearance-critical applications. It is designed for micro-volume soft encapsulation of optical heart-rate and SpO2 sensor windows, flex cables and mainboard areas in smartwatches and fitness trackers, protecting tiny components from sweat and wash water with minimal stress and compatibility with precision micro-dispensing. (EN) Backed by Hong Ye’s nearly 20 years of silicone manufacturing expertise and supplied to customers in over 60 countries, HY-9405 combines the performance of premium imported gels with the cost efficiency, short lead time and responsive technical support of a Chinese manufacturer. Whether you are running a first sample trial or ramping to full production, Hong Ye delivers consistent batch-to-batch quality, comprehensive documentation and application engineering support from first sample through full production.

Key Features:

• Premium anti-yellowing and UV-resistant formula maintains clarity and color stability through years of UV, heat and weather exposure.

• Excellent electrical insulation with dielectric strength above 20 kV/mm

• Repairable and reworkable: old gel can be topped up with fresh gel without full removal

• No VOC emissions during or after cure, suitable for enclosed cleanroom and medical environments

• Can be heat-cured at 60-80C for 30-60 minutes to shorten demolding time in mass production

• Resistant to ozone, UV, moisture, salt spray and common cleanroom cleaning agents

• 1:1 mix ratio by weight, easy to meter with manual or automated dispensing equipment

• Compatible with automated meter-mix dispensing equipment for high-volume production lines

• 12 month shelf life when sealed and stored below 25C in dry ventilated conditions

• Third-party test reports including RoHS, REACH, FDA and LFGB available on request

• Self-leveling after pouring, no vacuum degassing required, saving process time and equipment

• Recommended model: HY-9405 - Blue medium tack electronic potting jelly gel

Detailed Application Scenarios:

Wearable devices pack optical heart-rate and SpO2 sensors, flex printed circuits, connectors and battery protection boards into wrist-worn housings exposed to sweat, rain, hand washing and daily thermal cycling. HY-9405 is applied as a thin soft gel layer over sensor-adjacent electronics and board edges to seal out sweat and moisture without the high shrinkage stress that hard adhesives impose on tiny 0201 components and glass sensor windows. Its jelly-like consistency also damps micro-vibration and drop shock that can disconnect flex cables or misalign optical sensors.

For automated wearables assembly, the gel is compatible with precision needle dispensing in gram-level quantities, self-levels over small areas and can be heat-cured in under an hour to match short takt times. It resists repeated exposure to perspiration, soap and humidity while remaining chemically inert against common device plastics and elastomers. The soft gel can be reworked for board-level repair in manufacturing reflow processes. Hong Ye provides 1kg kits for NPI sampling and pail packaging for mass production, along with RoHS/REACH compliance and biocompatibility-friendly formulation options for skin-proximate devices.

Application & Operating Instructions:

Step 1 Surface preparation: Clean the housing or PCB with a dry lint-free cloth. Remove oil, moisture, flux residue and dust. For reliable adhesion, wipe with isopropyl alcohol and allow to fully dry.

Step 2 Component B preparation: Before each use, stir component B thoroughly for at least 2 minutes. Pigment and catalyst can settle during storage; incomplete stirring causes color variation and soft or uncured spots.

Step 3 Weighing and mixing: Weigh A and B at exactly 1:1 by weight using a calibrated scale. Pour into a clean container and stir slowly for 3 to 5 minutes, scraping the sides and bottom. Avoid fast stirring which introduces bubbles.

Step 4 Potting: Pour the mixed gel slowly into the housing, allowing it to flow around components and self-level. Do not pour from a height to avoid air entrapment. For deep or complex cavities, pot in layers.

Step 5 Curing: Allow 4 to 6 hours at 25C before handling; full properties develop after 24 hours. For mass production, heat-cure at 60-80C for 30-60 minutes. No vacuum degassing is required.

Step 6 Contamination prevention: Use polyethylene, nylon or nitrile gloves. Never use natural rubber latex gloves. Avoid contact with sulfur-containing materials, amines, phosphorus compounds, tin-cured silicone and PVC, as these inhibit the platinum catalyst.

Model Selection Guide:

The HY-94 series offers three standard grades to cover the full range of jelly gel applications, and custom formulations are available for volume orders:

HY-9400 (Blue, High Tack, Penetration 200): The soft, high-tack grade, designed for HEPA/ULPA filter gel seals in cleanrooms, biosafety cabinets, pharmaceutical GMP facilities, hospital operating rooms, semiconductor fabs, lithium battery dry rooms and data centers. Choose this model when strong self-healing and conformability to knife-edge channels are key requirements.

HY-9405 (Blue, Medium Tack, Penetration 170): The balanced all-rounder for instrument meter sealing, electronic encapsulation and outdoor waterproofing. Typical applications include smart water/gas/electric meters, automotive ECUs and sensors, solar PV junction boxes, LED modules, underwater lights, battery management systems and pressure sensors. Choose this model when you need a combination of flowability, structural support, vibration damping and repairability.

HY-9409 (Transparent, Low Tack, Penetration 150): The premium skin-contact grade for intimate apparel and medical products. Typical applications include silicone bra pads, push-up inserts, breast prostheses, nipple covers, bridal and swimwear gel pads, orthopedic insoles, baby products and surgical positioning pads. Choose this model when clarity, dry skin feel, anti-yellowing and body-safe materials are required.

If your project requires a different penetration, color, cure speed or special certification (FDA, LFGB, UL94), contact Hong Ye technical support for a custom formulation. Custom MOQ starts from 20kg and typical lead time is 7 to 10 working days.

Recommended Application: Wearable Smartwatch Sensor Soft Gel Encapsulation

Packaging:

Standard packaging options include 1kg trial kits (500g A + 500g B), 5kg kits, 20kg pails, 25kg pails and 200kg drums. Components A and B are supplied in separate containers within each kit. Custom packaging and private labeling are available for orders above 200kg. All kits are clearly labeled with batch number, manufacture date, expiry date and safety information.

Precautions:

Use polyethylene, nylon or nitrile gloves; never use natural rubber latex gloves. Avoid contact with sulfur-containing materials, amines, phosphorus compounds, tin-cured silicone and PVC, as these inhibit the platinum catalyst and prevent cure. Mix A and B at exactly 1:1 ratio by weight using a calibrated scale. Stir thoroughly for 3-5 minutes, scraping container walls and bottom. Do not exceed 100C during heat curing. Ensure good ventilation during operation.

Storage:

Store sealed containers in a dry, ventilated area below 25C, away from direct sunlight, sulfur-containing materials, amines, food and strong chemicals. Shelf life is 12 months from manufacture date. Reseal unused material immediately after dispensing. Refrigerated storage at 5-15C can extend shelf life; allow material to return to room temperature before opening to prevent condensation.

FAQ:

Q: How long does the gel take to cure and can I speed it up?

A: At 25C the gel reaches touch-dry in 4 to 6 hours and full properties after 24 hours. For mass production, heat-curing at 60 to 80C reduces the cycle to 30 to 60 minutes. Do not exceed 100C. Low temperatures below 15C will significantly slow the cure.

Q: Can potted electronics be repaired or reworked later?

A: Yes. Unlike hard epoxy, the soft jelly gel can be cut or peeled back to access components for repair, and fresh gel can be poured back over the area to restore protection. This repairability is a major advantage for serviceable outdoor and industrial electronics.

Q: What waterproof and insulation protection does it provide?

A: The cured gel provides continuous moisture and salt-spray protection with dielectric strength above 20 kV/mm and volume resistivity above 10^14 ohm-cm. Properly potted assemblies reliably meet IP65/IP67 requirements in outdoor environments.

Q: Will the soft gel stress sensitive components?

A: No. The low-modulus jelly gel cures into a soft mass that absorbs vibration and thermal expansion without exerting stress on fragile components, wires or solder joints, unlike rigid epoxy that can crack parts under temperature cycling.