Curing Principles And Technologies of Silicone Gel Materials

As an important polymer material, silicone gel is widely used in electronic packaging, medical devices, building sealing and other fields. Its magic lies in its ability to transform from a liquid state to an elastic solid state, and this transformation process is called curing. Understanding the curing principles and technologies of silicone gel can not only help us use this material better, but also help us find solutions quickly when problems arise.

1. Basic principles of silicone gel curing

1.1 What is curing?

Curing refers to the process of silicone gel transforming from a flowing state to an elastic body with a three-dimensional network structure. This process is like:

Liquid water → solid ice (physical state change)

Dough → toast (chemical structure change)

1.2 Chemical nature of curing

Silicone gel curing is mainly achieved through cross-linking reaction:

Linear molecules → three-dimensional network structure

Molecular weight from thousands → hundreds of thousands

Fluidity disappears, elasticity appears

II. Detailed explanation of the three major curing technologies

2.1 Condensation curing (room temperature curing RTV)

Working principle:

Reaction is triggered by moisture in the air, releasing small molecular by-products (such as ethanol)

Features:

Curing speed: 2-24 hours

Advantages: No heating equipment is required

Disadvantages: Shrinkage and odor may be generated

Typical application: building sealant

2.2 Addition curing (thermal curing)

Working principle:

Silicon hydrogen addition reaction is triggered by platinum catalyst

Features:

Curing temperature: 80-150℃

Advantages: No by-products, dimensional stability

Disadvantages: Heating equipment is required

Typical application: electronic packaging

2.3 Ultraviolet light curing (UV curing)

Working principle:

Ultraviolet light triggers photosensitizer to produce free radicals

Features:

Curing time: a few seconds to a few minutes

Advantages: ultra-fast, energy-saving

Disadvantages: limited to thin layer curing

Typical applications: optical coatings

III. Key factors affecting curing

3.1 Effect of temperature

The reaction rate increases by 10°C for every increase in temperature

But too high a temperature will cause the catalyst to deactivate

3.2 Effect of humidity

Condensation type curing requires an appropriate amount of moisture

Too low humidity will delay curing

3.3 Thickness restrictions

Addition type: recommended <10mm

Condensation type: recommended <15mm

UV type: recommended <2mm