Respiratory Mask LSR Overmolding on Plastic

I. Product Overview

A respiratory mask is a core component in medical care, nursing and industrial protection. Traditional masks made of a single rigid plastic or ordinary silicone gasket often suffer from poor sealing, weak fit, and obvious pressure marks during long-term wear. The respiratory mask LSR overmolding on plastic technology combines a transparent PC/PET plastic frame with a soft liquid silicone rubber (LSR) sealing layer through precision injection molding, delivering both structural rigidity and skin-friendly elasticity - a "rigid-flexible" medical-grade sealing solution.

This product is widely used in medical oxygen masks, CPAP sleep therapy masks, nebulizer masks, emergency resuscitation masks and industrial protective masks. Size, color and sealing structure can be customized according to customer requirements.

II. Core Advantages

1. Medical-grade Sealing and Precise Fit

The LSR sealing layer is molded in one piece along the 360-degree mask edge, elastically conforming to facial contours and eliminating air leakage gaps. When used with CPAP positive airway pressure, leakage is minimized, improving treatment effectiveness and wearing comfort.

2. Skin-friendly Softness for Long-term Comfort

Liquid silicone provides a soft, delicate touch (Shore A 20-40 adjustable), with minimal pressure on sensitive areas such as the nose bridge and cheekbones. Better breathability and moisture management than traditional rubber make it suitable for overnight use.

3. Medical-grade Material Safety

Medical-grade LSR certified to USP Class VI and ISO 10993 biocompatibility standards is selected. It is odorless, non-toxic, low-allergenic and plasticizer-free, safe for skin contact; the transparent plastic frame meets relevant medical material standards.

4. Sterilization and Aging Resistance

LSR withstands high-temperature autoclave sterilization and ethylene oxide disinfection without yellowing or hardening over time, and offers excellent ozone and UV resistance for a long service life.

5. Integrated Structure and Easy Cleaning

The silicone layer is seamlessly bonded to the frame with no hidden crevices, allowing repeated cleaning and disinfection. High structural strength, tear resistance and deformation resistance suit high-frequency use.

III. Molding Process

3.1 Two-shot Injection Molding Flow

Step 1 - Plastic Frame Injection: Medical-grade transparent PC or PP is precision molded into the mask frame (wall thickness 1.0-2.0mm, mold temperature 80-120°C) to ensure optical clarity and dimensional accuracy.

Step 2 - LSR Overmolding: The frame is placed into the overmolding tool and medical-grade liquid silicone is injected. Key parameters: mold temperature 150-170°C, injection pressure 60-100MPa, curing time 40-90s, seal thickness 0.5-2.0mm.

3.2 Bonding and Mold Key Points

- The frame surface is plasma-activated or primer-treated so that LSR bonds firmly to PC/PP without delamination during long-term use;
- Submarine gates are adopted to avoid visible gate marks;
- Mold temperature uniformity is controlled within ±2°C for consistent curing;
- Mirror-polished cavity surfaces ensure a smooth, flash-free sealing layer.

IV. Quality Control

- Visual inspection: AOI automatic optical inspection for voids, bubbles and flash;
- Air leak test: positive and negative pressure tests meet medical standards;
- Peel test: 90-degree peel test confirms qualified LSR-to-frame adhesion;
- Biocompatibility: full cytotoxity, sensitization and irritation tests (ISO 10993);
- Aging test: 85°C/85%RH aging for 1000 hours without significant degradation.

V. Customization Service

We provide a full-chain service from mask structure design, mold development and material selection to mass production, supporting OEM/ODM customization. Size, hardness, color, logo and packaging can be adjusted according to customer requirements. Please contact us for inquiries.