What are the reasons and corresponding solutions for the delamination of silicone integrated molding of hardware packages?

1、 Characteristics of raw materials

1. Compatibility between silicone and hardware components

There are differences between silicone and hardware in terms of chemical structure, surface energy, solubility parameters, etc., which directly affect the intermolecular forces between them. If the compatibility between the two is poor and they are directly integrated without special treatment, it is easy for them to detach due to external forces or environmental changes during subsequent use. Therefore, choosing silicone and hardware materials with good compatibility is the key to avoiding delamination problems.

2. Quality of silicone raw materials

The quality of silicone raw materials directly affects their performance after molding. The selection and dosage of vulcanizing agents, as well as the uniformity of raw material mixing, are all key factors. Improper selection or inaccurate addition of vulcanizing agents can lead to incomplete or excessive curing of silicone, thereby affecting its bonding strength with hardware components. In addition, uneven mixing of raw materials can also lead to defects inside the silicone gel, reducing its overall performance.

3. Surface treatment of hardware components

Before the hardware is coated with silicone for integrated molding, its surface must undergo special treatment to enhance its adhesion with silicone. Common treatment methods include cleaning surface stains, applying primer, etc. If the surface treatment is improper or the primer selection is inappropriate, it will directly affect the bonding effect between silicone and hardware, leading to delamination problems.2、 Forming process

1. Mold design

The rationality of mold design directly affects the contact between silicone and hardware during the molding process. If there are defects in the mold design, such as uneven contact surfaces and stress concentration points, it will result in insufficient contact or uneven stress on the contact surface between silicone and hardware during the molding process, thereby affecting the bonding strength. Therefore, optimizing mold design to ensure smooth contact surfaces and uniform force distribution is crucial.

2. Injection temperature and pressure

Injection temperature and pressure are important factors affecting the fluidity of silicone gel. If the injection temperature is too low or the pressure is insufficient, it will cause poor fluidity of the silicone gel, which cannot fully fill the mold and form a good bonding interface with the hardware; On the contrary, if the temperature or pressure is too high, it may cause excessive flow or burning of the silicone gel, which also affects the bonding strength. Therefore, in the process of injection molding or compression molding, it is necessary to accurately control parameters such as temperature, pressure, and time to ensure the quality of hardware molding while also providing good substrate conditions for subsequent silicone injection or coating.

3. Sulfurization time and temperature

Sulfurization is one of the key steps in the silicone molding process. Insufficient vulcanization time or low temperature can lead to incomplete or insufficient curing of silicone, thereby affecting its bonding strength with hardware components. In addition, during the vulcanization process, attention should be paid to controlling the environmental humidity and air circulation to avoid moisture or oxidation of the silicone gel. Optimize parameters such as vulcanization temperature, time, and pressure to ensure sufficient vulcanization of silicone while avoiding damage to hardware substrates.

3、 Working environment and operating techniques

1. Work environment

The cleanliness, temperature and humidity of the work environment can also have an impact on the delamination problem of silicone integrated molding of hardware components. For example, the presence of dust, oil stains, and other impurities in the work environment can contaminate the surface of silicone or hardware components; Excessive or insufficient temperature and humidity may affect the curing effect of silicone gel. Therefore, it is crucial to strengthen the cleanliness and temperature and humidity control of the work environment.

2. Operational techniques

The cleanliness of the operator’s hands and the standardization of the coating process can also affect the bonding effect between silicone and hardware. Improper operation or uneven application of primer may lead to delamination issues. Therefore, it is necessary to standardize the operating methods and processes of operators to ensure that the coating process of the primer is standardized, uniform, and completed within the specified time.

4、 Solution

1. Optimize material selection

Choose hardware materials that have good compatibility with silicone, such as certain specially modified alloys or stainless steel. At the same time, consider pre-treatment on the surface of hardware components, such as plasma treatment, chemical etching, or coating with thickening agents, to improve their surface energy and enhance their adhesion to silicone gel.

2. Improve the molding process

Optimize mold design to ensure smooth contact surfaces and uniform force distribution; Adjust the injection temperature and pressure parameters to the optimal range; Strictly control the vulcanization time and temperature to ensure complete curing of the silicone gel. In addition, two-component injection molding technology can be used, which involves molding silicone and hardware components in one go in a mold, and utilizing the special structure of the injection molding machine to achieve seamless bonding between the two materials.

3. Strengthen the control of homework environment

Keep the work environment clean and dry, and avoid contaminating the surface of silicone or hardware with impurities such as dust and oil stains. At the same time, control the temperature and humidity of the work environment within an appropriate range to ensure the curing effect of the silicone gel.

4. Standardize operating procedures

Provide professional training to operators to ensure they are familiar with and comply with operating procedures. During the process of applying the primer, it is necessary to strictly follow the required ratio of the primer, apply it evenly, and complete the molding within the specified time. At the same time, strengthen the maintenance and upkeep of equipment and tools to ensure they are in good condition.

5. Regular maintenance and inspection

For products that are used for a long time, a regular maintenance plan should be developed to check the bonding between silicone and hardware, and to promptly identify and address potential risks of detachment. For products that have already experienced delamination issues, timely repair or replacement should be carried out to avoid adverse effects on product quality and service life.

In summary, there are various reasons for the problem of delamination in the silicone integrated molding of hardware components, which need to be comprehensively analyzed and solved from multiple aspects such as raw material characteristics, molding process, working environment, and operating methods. By optimizing material selection, improving molding processes, strengthening work environment control, standardizing operating methods, and conducting regular maintenance inspections, the occurrence of delamination problems can be effectively avoided, and product quality and production efficiency can be improved.