two-color injection-molded silicone products for grips

The Two-color injection-molded silicone products process can achieve soft-hard combination, color splicing, and functional zone segmentation on a single part, and is widely used in consumer and industrial items that require a comfortable touch, sealing, anti-slip properties, or aesthetic zoning, such as handles, buttons, sealing rings, medical device components, and electronic appearance parts.

Typical applications:

1. Handles and grip parts: integration of soft grip areas with a rigid support core to enhance holding comfort and durability.
2. Keys and panels: two-color, clearly two-toned key surfaces that balance tactile feel and visual identification.
3. Seals and valve parts: create different hardness zones on sealing rings or valve seats to meet sealing and elasticity requirements.
4. Children’s and medical products: use non-toxic silicone to provide comfortable surfaces and structured support.
5. Electronic decorative parts and sleeves: weather-resistant, anti-yellowing appearance parts with color segmentation.
6. Compression cushioning and anti-slip parts: combine energy absorption and abrasion resistance functions to enhance protection.

Common materials and characteristics of Two-color injection-molded silicone products:

1. LSR (liquid silicone rubber): good flowability, capable of high-precision textures and details, resistant to high and low temperatures, and non-toxic.
2. TPE, TPV modified silicones (co-injected with silicone or in composite structures): used to achieve different hardness levels or cost optimization.
3. Different hardness pairings: combinations of a hard core (such as higher-hardness silicone or engineering plastics) with soft-skin silicone to balance structural support and comfortable touch.
4. Colorants and additives: use colorants and functional fillers that comply with ROHS, food-grade, and medical-grade standards to meet weather resistance, antibacterial, or flame-retardant requirements.

Injection molding process and production flow:

1. Material preparation: prepare LSR or silicone material according to the formulation, control mixing ratios, degassing and deaeration, and add color in batches if necessary.
2. Mold and machine preparation: use two-color injection systems, rotary tables, dual-shot nozzles molds, or 2K injection equipment, and select appropriate temperature control and metering systems according to the process.
3. First injection and molding: form the first material first (usually the substrate or hard core), completing curing or positioning.
4. Second injection: inject the second material into the first part while it is still in the mold or after positioning to achieve co-flow or overmolded structures.
5. Post-curing and cooling: perform necessary vulcanization or post-curing treatment according to the silicone type to ensure material properties.
6. Secondary processing and inspection: trimming, deburring, cleaning, functional testing and appearance inspection; perform laser marking or pad printing when necessary.

Surface treatment and post-processing:

1. Mold texture and matte/gloss control: achieve different tactile and visual effects through mold surface treatments.
2. Coloring and printing: two-color molded parts can reduce subsequent painting processes; support pad printing, inkjet, or laser marking when necessary.
3. Coatings and antibacterial treatments: functional surface coatings can be added (for example, anti-stick, anti-fingerprint or antibacterial coatings).