What is the reason for the delamination of silicone plastic integrated molding?

The reason for the delamination of silicone plastic integrated molding is a complex and multidimensional problem, involving multiple aspects such as raw materials, molding process, working environment, and operating methods.

1、 Raw material factors

1. Compatibility between silicone and plastic

There are differences between silicone and plastic 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 come loose due to external forces or environmental changes during subsequent use. Therefore, choosing silicone and plastic 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. For example, 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 gel, thereby affecting its bonding strength with plastic. In addition, uneven mixing of raw materials can also lead to defects inside the silicone gel, reducing its overall performance.

3. Surface treatment of plastic skeleton

Before the plastic skeleton 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 plastic, leading to delamination problems.

2、 Forming process factors

1. Mold design
The rationality of mold design directly affects the contact between silicone and plastic 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 plastic during the molding process, thereby affecting the bonding strength.
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 plastic; 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.
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 plastic. 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.

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 plastic integrated molding. For example, the presence of dust, oil stains, and other impurities in the work environment can contaminate the surface of silicone or plastic; Excessive or insufficient temperature and humidity may affect the curing effect of silicone gel.
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 plastic. If hands are contaminated with corrosive substances such as oil and sweat, it may corrode the primer on the surface of the plastic skeleton; If the primer is contaminated or not used up within the specified time during the coating process, it may also cause delamination problems.

4、 Solution

To address the issue of delamination in the integrated molding of silicone and plastic bags, solutions can be taken from the following aspects:
1. Select silicone and plastic materials with good compatibility and conduct sufficient experimental verification.
2. Strictly control the quality of silicone raw materials to ensure that the selection and addition of vulcanizing agents, as well as the uniformity of raw material mixing, meet the requirements.
3. Thoroughly clean and apply primer to the surface of the plastic skeleton to ensure that its bonding surface with silicone is clean, smooth, and free of impurities.
4. Optimize the mold design to ensure a smooth contact surface 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.
5. Strengthen the cleanliness and temperature and humidity control of the work environment; Standardize the operating techniques and processes of operators; Regularly maintain and upkeep equipment and tools.
In summary, there are various reasons for the problem of delamination in the integrated molding of silicone and plastic bags, which require comprehensive analysis and solutions from multiple aspects such as raw materials, molding processes, working environments, and operating methods. Only in this way can we ensure the quality and reliability of silicone plastic integrated molding products.