In-depth understanding of the performance and application of potting glue

Potting adhesive is a kind of adhesive material used to fill, seal or protect electronic components, devices or devices, which plays an important role in the electronic industry, construction engineering and other fields. The potting glue is liquid before curing, has fluidity, and can penetrate into the tiny gaps of electronic components. After curing, it forms a solid protective layer, which plays a role of waterproof, moisture-proof, dust-proof, insulation, heat conduction, and anti-corrosion., Temperature resistance, shockproof and other protection functions. Through potting treatment, the electrical and mechanical properties of the components are comprehensively improved, the failure rate caused by vibration, shock and other factors is reduced, and the stability, reliability and service life of the product are significantly improved.

The performance of the potting adhesive directly affects the precision and timeliness of the operation of electronic products, and the weather resistance, chemical resistance, electrical insulation, mechanical strength, operating temperature range and cost should be considered when selecting the appropriate potting adhesive. At present, the most common potting glue on the market mainly includes epoxy resin potting glue, silicone potting glue and polyurethane potting glue, each type has its own unique advantages and disadvantages and application scenarios.

Analysis of the advantages and disadvantages of various types of potting glue in 1.

1. Epoxy resin potting adhesive

Epoxy resin potting adhesive is a kind of potting material widely used at present, its main characteristics and properties are as follows:

Advantages:

Epoxy resin potting glue has excellent bonding ability, has excellent adhesion to a variety of metal substrates and porous substrates, has high mechanical strength and hardness, good rigidity after curing, excellent electrical insulation performance, strong chemical corrosion resistance, relatively economical price, suitable for cost-sensitive application scenarios.

Disadvantages:

Epoxy resin potting adhesive has weak resistance to cold and heat changes, and is prone to cracks after being impacted by cold and heat, causing water vapor to penetrate into electronic components from the cracks. After curing, the colloid has high hardness and brittleness, which is easy to strain electronic components. Once the potting is cured, it is difficult to open due to high hardness, and components cannot be replaced. Transparent epoxy resin material has poor weather resistance and is easy to yellowing under light or high temperature.

2. Silicone potting

As a high-performance potting material, silicone potting adhesive has unique comprehensive properties:

Advantages:

Silicone potting adhesive has a wide working temperature range (-50 ℃ ~ 200 ℃), can maintain elasticity and no cracking in extreme high and low temperature environments; has excellent weather resistance and anti-aging ability, and can maintain protection in outdoor environments For more than 20 years; excellent electrical insulation performance, which can effectively improve the insulation capacity between internal components and circuits; has excellent repair ability, the sealed components can be easily removed for repair and replacement; there is no corrosion to the components, and no by-products are produced in the curing reaction.

Disadvantages:

The main disadvantages of silicone potting are relatively poor bonding properties and insufficient adhesion to certain materials; compared to other types of potting, the price of silicone potting is usually higher, which may increase product costs.

3. Polyurethane potting compound

Polyurethane potting has unique value in specific application scenarios:

Advantages:

Polyurethane potting adhesive has excellent low temperature resistance and can still maintain good elasticity in low temperature environment. The material is relatively soft and has good adhesion to general potting materials, and the adhesion is between epoxy resin and organic silicon. It has good waterproof, moisture-proof and insulation properties and can effectively protect electronic components.

Disadvantages:

Polyurethane potting glue has poor high temperature resistance and is easy to foam, so vacuum defoaming process is usually required. After curing, the colloid surface is not smooth and has poor toughness, weak anti-aging ability and anti-ultraviolet ability. After long-term use, the colloid is easy to change color and affect aesthetics.

Application range of 2. potting glue

1. Application fields of epoxy resin potting glue

Epoxy resin potting glue is mainly suitable for scenes that do not require high bonding strength and ambient temperature. Common applications include: LED products, transformers, regulators, industrial electronic equipment, relays, controllers, power modules and other non-precision electronic devices Potting. These applications are typically in ambient or relatively stable environments and are cost-sensitive.

2. Application fields of silicone potting

Silicone potting adhesive is suitable for high-end precision and sensitive electronic devices working in various harsh environments. Typical applications include: LED display screens, photovoltaic materials, diodes, semiconductor devices, relays, sensors, automotive stability devices HIV, on-board computer ECU, etc. These applications often have high requirements for temperature range, durability and reliability, and may require subsequent maintenance and component replacement.

3. Application fields of polyurethane potting glue

Polyurethane potting glue is generally used in the potting of electronic components with low heat generation. Common applications include transformers, anti-current coils, converters, capacitors, coils, inductors, rheostats, linear motors, fixed rotors, circuit boards, LEDs, pumps, etc. These applications are usually in indoor environments and are not affected by extreme temperature changes.

Common Advantages, Disadvantages and Development Trend of 3. Potting Adhesive

Although the properties of various types of potting adhesives are different, they also have some common advantages and limitations. The potting adhesive has excellent sealing performance and can effectively isolate external moisture, dust and corrosive gases; it provides multi-directional protection functions, including waterproof, moisture-proof, dust-proof, insulation, heat conduction, shockproof, etc.; it can significantly improve the stability and reliability of components, prolong the service life; and a wide variety, strong adaptability, can choose the appropriate material formula according to different needs.

Potting glue also has some general limitations, such as long curing time, some products need a long time to be completely cured at room temperature; it is easy to produce bubbles, if the operation is improper or the material itself contains bubbles during the potting process, it will affect the potting effect; it is difficult to repair, once the components are potted, it is difficult to repair when the internal failure occurs; in addition, the cost is high, high-performance potting materials and process requirements increase product costs.

With the development of the electronic industry, potting is moving towards high performance, specialization, environmental protection direction, the future will have more low temperature rapid curing, high thermal conductivity, high flame retardant, biodegradable recycling of new potting materials come out, to meet the growing reliability requirements of electronic products.