LSR Overmolding on PPO: The Perfect Fusion of Waterproof Sealing, Skin-friendly Touch and Food-grade Safety

I. What is PPO? Why LSR Overmolding on PPO?

PPO (Polyphenylene Oxide) is a high-performance engineering plastic with excellent heat resistance (-40°C to 105°C), electrical insulation, and dimensional stability. LSR overmolding on PPO coats liquid silicone rubber onto the PPO substrate surface through precision injection molding, achieving a composite structure that combines rigidity with elasticity.

II. Three Core Performance Advantages

2.1 IP68 Waterproof Sealing

LSR coating completely seals assembly gaps and screw holes. With excellent fluidity (3000-8000 mPa·s), LSR penetrates microscopic gaps for zero-clearance sealing. Chemical bonding at the interface ensures peel strength ≥5N/mm. Typical applications include smart toilet remote controls, electric toothbrush handles, and kitchen scale panels.

2.2 Skin-friendly Soft Touch

LSR coating provides Shore A 20-50 adjustable hardness, matte texture options, and 60%+ improved grip in wet conditions. Low thermal conductivity (0.2 W/m·K) ensures comfortable touch in all seasons. Applied in high-end electric toothbrush handles, beauty devices, and baby thermometers.

2.3 Food-grade Safety Certification

Selects USP Class VI or FDA 21 CFR 177.2600 certified medical/food-grade LSR. Odorless, no plasticizer migration. Dishwasher safe and boil disinfection compatible (-50°C to 200°C). Optional silver ion antibacterial additive (≥99.9% antibacterial rate per ISO 22196). Applications: baby food processor seals, coffee machine gaskets, water dispenser nozzles.

III. Molding Process

Step 1 - PPO Base Injection: Precision injection of PPO frame (wall thickness 1.0-2.0mm, mold temp 80-120°C, injection temp 280-320°C).

Step 2 - LSR Overmolding: Key parameters: mold temp 150-170°C, injection pressure 50-80MPa, curing time 40-80s, coating thickness 0.5-2.0mm.

Bonding Solutions: Plasma activation (250W, 45s) + primer (3-5μm), peel strength 6-8N/mm. UV grafting or mechanical interlock design options available.

IV. Applications

Kitchen appliances (electric toothbrushes, coffee machine seals), baby products (feeding spoons, bottle warmers), personal care (beauty device handles, facial cleansers), smart home (toilet remote controls, bathroom waterproof panels), medical (thermometers, nebulizer mask seals).

V. Quality Standards

AOI visual inspection, peel strength &ge;5N/mm (ASTM D429), IP68 leak test (0.3MPa, 30s, leakage<3mL/min), food contact testing (FDA 21 CFR 177.2600), aging test (85&deg;C/85%RH, 1000h), antibacterial test (ISO 22196, R&ge;2.0).