I. Introduction to Two-Component Silicone Potting Compound:

1. Two-component silicone potting compound is a potting material that requires mixing of two components—A and B—and cures either at room temperature or with heat. Its primary functions include sealing, waterproofing, and thermal conductivity.

2. Depending on the curing mechanism, they can be classified into addition-cure and condensation-cure types. Addition-cure potting compounds typically have an A-to-B component ratio of 1:1; component A is black, while component B is white, and the mixed product appears grayish-black.

3. Silicone gel is also a addition-cure, two-component silicone potting compound; it typically contains no fillers and, upon curing, exhibits a transparent color (though it may be blue or other colors as required).

4. Condensation-type potting compounds typically have an A-to-B component ratio of 10:1 or 5:1. Component A is available in transparent, black, or white, while Component B is transparent.

II. Main characteristics of two-component silicone potting compounds:

1. Two-component addition-cure silicone potting compounds are completely non‑toxic, offer excellent workability, and are very easy to apply. They exhibit outstanding degassing properties and can be formulated to provide superior thermal conductivity as required. After curing, they generate low internal stress and are highly amenable to rework and cleanup. They also demonstrate excellent weather resistance and an exceptionally broad temperature range, from –40°C to 250°C; however, their adhesion performance is relatively poor.

2. Condensation-cure silicone potting compounds cure at room temperature in the presence of moisture and exhibit moderate adhesive properties after curing. They are primarily used for potting applications where thermal conductivity is not a critical requirement but high waterproofing is essential.

III. Market Applications:

1. Addition-cure potting compounds are primarily used in applications requiring waterproof sealing and thermal conductivity, such as drive power supplies, control modules, reactors, transformers, inverters, optimizers, heating coils, and more.

2. Silicone gel is primarily used in high-purity applications, such as IGBTs, thyristors, pressure sensors, automotive electronic modules/sensors/wiring harnesses, smart water meters, waterproof electrical junction boxes, filters, rain‑light sensors, camera systems, and optical sensors.

3. Condensation-cure silicone potting compounds are primarily used in LED lighting, solar energy applications, and more.

IV. Instructions for Use:

1. Applying the sealant: Use manual or automated equipment to uniformly mix components A and B according to the specified weight ratio. When mixing by hand, ensure thorough agitation of the container’s edges and bottom. In applications sensitive to air entrainment, perform vacuum degassing. Place the component to be sealed with the opening facing upward in a horizontal position, pour in the potting compound, and allow it to self‑level.

2. Curing: Addition‑cure potting compounds cure rapidly at room temperature or with moderate heating; the higher the temperature, the faster the cure. Condensation‑cure potting compounds cure at room temperature and must not be heated.

V. Precautions:

1. For addition-cure potting compounds containing fillers, prolonged standing may cause sedimentation. It is recommended to thoroughly stir components A and B separately before use, and to store the mixture in a sealed container after dispensing.

2. During mixing, ensure that stirring is performed in a consistent direction; otherwise, excessive air bubbles may be entrained. The adhesive at the container’s edges and bottom must also be thoroughly mixed to prevent localized uncuring caused by uneven mixing.

3. Pouring the material onto the product and then evacuating to remove air bubbles can enhance the overall performance of the cured product.

4. If the temperature of addition-cure potting compounds is too low, the curing rate will be slower; we recommend heating to accelerate curing.

5. Addition‑cure potting compounds may fail to cure or cure poorly when in contact with materials containing tin, sulfur, amines, and similar substances. Common examples include rosin and natural rubber; a compatibility test should be conducted prior to use.

The above content is an introduction by Shanghai Hinnel to the root causes of bubble formation in silicone potting compounds and their corresponding solutions. For more information on the performance of silicone products and related updates, please feel free to call us for detailed inquiries.

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