Can dual injection molded liquid silicone be combined with PC?

The combination of dual injection molded liquid silicone and PC (polycarbonate) is a highly concerned topic in modern manufacturing. These two materials have excellent performance in their respective fields, and combining them can create a new product that combines the softness, high and low temperature resistance, and corrosion resistance of silicone with the high strength, high transparency, and good impact resistance of PC.

1、 Feasibility of Combining Liquid Silicone with PC

Liquid Silicone Rubber (LSR) is a non-toxic, heat-resistant, and highly recoverable flexible thermosetting transparent material made of organic silicone. It has excellent transparency, tear resistance, resilience, thermal stability, and weather resistance, and can maintain excellent performance over a wide temperature range of -60 ℃ to 250 ℃. LSR injection molding liquid silicone is suitable for injection molding process and can produce high-precision, high-strength, and high tear resistant silicone products.
PC（Polycarbonate）， Polycarbonate is a high-performance thermoplastic engineering plastic. It has outstanding impact resistance, creep resistance, good dimensional stability, heat resistance, low water absorption, non toxicity, and excellent dielectric properties. The transparency of PC is the most outstanding among all five major engineering plastics, and it has good wear resistance and processing performance, making it an ideal material for manufacturing high-quality transparent products.
In terms of material compatibility, liquid silicone and PC can theoretically be processed. The silicone layer formed by the solidification of liquid silicone has good adhesion and can firmly adhere to the surface of PC material, forming an effective protective layer. Meanwhile, the high strength and transparency of PC can also provide excellent appearance and quality for encapsulated products. Therefore, through appropriate processing methods such as double injection molding technology, the combination of liquid silicone gel and PC can be achieved.

2、 Process of Double Injection Molding Liquid Silicone Packaging PC Plastic
The process of double injection molding liquid silicone packaging PC plastic mainly includes the following steps:

1. Injection molding of PC substrate: PC material is processed into the desired substrate shape through high-temperature and high-pressure injection molding technology. This process requires strict control of temperature and pressure to ensure the physical properties and dimensional accuracy of the PC substrate. Common PC products include phone cases, watch straps, and other main frames.
2. Surface treatment: In order to improve the adhesion between liquid silicone gel and PC substrate, surface treatment is usually required on the PC substrate. The methods of surface treatment include spraying adhesive, plasma treatment, etc. These technologies can improve the wettability of PC surfaces and enhance the adhesion between silicone and PC.
3. Liquid silicone coating: After the PC substrate is formed and surface treated, liquid silicone is injected into the surface or specific area of the PC substrate according to the predetermined design through a specialized injection molding machine. This process requires high-precision molds and equipment to ensure that liquid silicone can adhere evenly and seamlessly to the PC substrate, and form a strong bond. Usually, a secondary injection molding process is used, which involves molding the PC substrate and then encapsulating it with silicone injection molding.
4. Curing and cooling: Liquid silicone gel needs to be cured at a certain temperature after injection to form a stable silicone layer. During the curing process, it is necessary to strictly control the temperature and time to ensure that the silicone can be completely cured and form good adhesion. After solidification, the product undergoes cooling treatment for subsequent processing and quality inspection.
5. Quality inspection and post-processing: The finished product needs to undergo various tests, such as temperature resistance, moisture resistance, adhesion testing, etc., to ensure that it can maintain excellent performance in various usage environments. Products that pass quality inspection undergo post-processing, such as trimming burrs, cleaning surfaces, etc., to improve the appearance quality and durability of the products.

3、 Precautions and optimization measures

In the process of double injection molding liquid silicone encapsulated PC plastic, it is necessary to pay attention to the following aspects and take corresponding optimization measures:
1. Temperature control: Liquid silicone gel needs to be cured at a certain temperature to form, while PC may deform or discolor at high temperatures. Therefore, during the encapsulation process, it is necessary to strictly control the processing temperature to ensure that the liquid silicone gel solidifies at the appropriate temperature, while avoiding adverse effects on the PC material.
2. Adhesive selection: In order to enhance the adhesion between liquid silicone and PC, it is necessary to choose a suitable adhesive. The selection of adhesive should be determined based on the specific types and processing conditions of liquid silicone and PC. By selecting the appropriate adhesive, the bonding strength between silicone and PC can be significantly improved, ensuring the quality and durability of the final product.
3. Process parameter optimization: During the encapsulation process, the setting of process parameters has a crucial impact on product quality. It is necessary to determine the optimal process parameters through experiments and optimization, such as injection speed, injection pressure, curing time, etc. By optimizing process parameters, it can be ensured that liquid silicone can evenly cover the surface of PC, forming a strong bond.
4. Mold design: The design accuracy and manufacturing quality of the mold have a significant impact on the quality of double injection molded liquid silicone wrapped PC plastic products. High precision mold design and manufacturing techniques are required to ensure that silicone can adhere uniformly and seamlessly to the PC substrate, and form product shapes and sizes that meet design requirements.
5. Material selection: The material selection of liquid silicone and PC is also a key factor affecting product quality. It is necessary to choose raw materials with stable quality and excellent performance to ensure the quality and performance of the final product. At the same time, it is necessary to consider the environmental friendliness and sustainability of materials to meet the requirements of modern manufacturing industry for environmental protection and sustainable development.

4、 Application Fields and Development Prospects

The double injection molding liquid silicone encapsulation PC plastic technology has a wide range of application fields and development prospects. Here are some typical application areas:
1. Electronic products: The combination of liquid silicone and PC can be used to manufacture electronic product accessories such as phone cases, tablet protective cases, smart watch straps, etc. These products not only have excellent mechanical performance and a good user experience, but also provide protection functions such as anti drop, waterproof, dustproof, etc., extending the service life of electronic products.
2. Automotive parts: The combination of liquid silicone and PC can also be used to manufacture automotive parts, such as steering wheel covers, shift lever covers, door handles, etc. These products not only have high strength and transparency, but also provide anti slip, wear-resistant, weather resistant and other properties, improving driving safety and comfort.
3. Medical devices: The combination of liquid silicone and PC can also be used to manufacture medical devices, such as surgical instrument handles, medical catheters, etc. These products not only have excellent biocompatibility and corrosion resistance, but also provide a soft and comfortable feel, reducing the operational burden on medical staff.
4. Household goods: The combination of liquid silicone and PC can also be used to manufacture household goods, such as remote control housings, water bottles, tableware, etc. These products not only have a beautiful appearance and excellent performance, but also provide functions such as anti slip, heat resistance, and drop resistance, improving the comfort and convenience of home life.

The encapsulation processing technology of liquid silicone and PC is also constantly improving and perfecting. The research and application of new materials and processes will further promote the development of the combination technology of liquid silicone and PC, providing more possibilities and choices for the development of various industries.