Production process and function of dual color conductive liquid silicone accessories
The molding production of dual-colored conductive silicone rubber accessories is a traditional yet highly reliable molding process, especially suitable for manufacturing precision components with complex structures, strict requirements for conductivity, and requiring large-area encapsulation or embedded structures (such as plug sealing rings, multifunctional instrument buttons, etc.).
The following is a detailed explanation of its molding production process and its role:
Ⅰ. Molding production process
The core of dual-color conductive silicone rubber molding lies in achieving molecular-level bonding between two types of silicone rubber with different characteristics within the mold through two feeding processes and thermal vulcanization.
1. Raw material preparation and preforming
According to the product performance requirements, two types of adhesives are prepared: one is conductive silicone rubber filled with conductive fillers (such as silver-plated nickel powder, conductive carbon black, silver-plated glass microspheres); the other is insulating silicone rubber without conductive fillers. The two adhesives are separately mixed through an open mill and cut into adhesive blanks of specific weight and shape for placement into the mold cavity.
2. First feeding and molding
Place the conductive silicone rubber blank into the lower mold cavity or specific conductive area. After mold closing, conduct the first vulcanization under high temperature (usually 160°C-180°C) and high pressure. This stage usually adopts a semi-vulcanization process, which allows the conductive silicone rubber to be initially set but retains chemical activity on the surface, preparing for subsequent bonding.
3. Secondary feeding and molding
Open the mold, fill the semi-finished conductive silicone rubber matrix with insulating silicone rubber paste. Re-close the mold for the second high-temperature and high-pressure vulcanization. Under pressure, the insulating silicone rubber flows and fills the remaining cavity, while undergoing a co-vulcanization reaction with the conductive silicone rubber at the interface, forming a strong integrated structure.
4. Secondary vulcanization and finishing
The molded product undergoes secondary vulcanization (baking) to eliminate internal stress and stabilize its elasticity and conductivity. Finally, burrs are removed through manual or frozen trimming, and quality inspection is completed.
ⅡCore role
1. Realize the composite function of conductivity and insulation
The molding process can control the distribution of conductive silicone gel. For example, in the sealing ring of a connector, conductive silicone is used for the internal closed circuit to ensure grounding continuity between the body and the panel, and insulating silicone is used for the external contact part to prevent accidental current contact. This composite structure cannot be achieved with a single material.
2. Provide excellent compressive and sealing performance
The high pressure of compression molding makes the molecular structure of silicone gel dense. The conductive part not only conducts current, but also plays a role in electromagnetic shielding (EMC); The insulation part utilizes the high resilience of silicone to maintain stable waterproof and dustproof sealing under severe temperature changes or vibration environments.
3. Endure harsh environments
Due to the complete encapsulation of conductive fillers by silicone substrates, molded products can maintain stable conductivity and physical structure even in long-term outdoor exposure, ozone or salt spray corrosion environments, without problems such as coating peeling or conductive particle migration and short circuits.
