Material saving, labor-saving, low cost, small deformation TIM material high thermal conductivity potting adhesive

1Composition of adhesive

The adhesives currently used are synthetic resin adhesives made of multiple components, and single component adhesives can no longer meet the requirements in use. Synthetic adhesives are composed of a main agent and auxiliary agents, with the main agent also known as the main material, base material, or adhesive; Auxiliaries include curing agents, diluents, plasticizers, fillers, coupling agents, initiators, thickeners, anti-aging agents, polymerization inhibitors, stabilizers, complexing agents, emulsifiers, etc. Depending on requirements and applications, they can also include flame retardants, foaming agents, defoamers, coloring agents, and mold inhibitors.

1. Main agent

The main agent is the main component of the adhesive, which dominates the bonding performance of the adhesive and is also an important indicator to distinguish the type of adhesive. The main agent is generally composed of one or two, or even three high polymers, requiring good adhesion and wetting properties. The commonly used adhesives are:

·Natural polymer compounds

Such as protein, skin glue, fish glue, rosin, peach glue, bone glue, etc.

2) Synthesis of polymer compounds

① Thermosetting resins, such as epoxy resin, phenolic resin, polyurethane resin, urea formaldehyde resin, organic silicon resin, etc.

② Thermoplastic resins, such as polyvinyl acetate, polyvinyl alcohol and aldehyde resins, polystyrene, etc.

③ Elastic materials such as nitrile rubber, chloroprene rubber, polysulfide rubber, etc.

④ Mixtures or grafts, inlays, and copolymers of various synthetic resins and synthetic rubbers.

2. Additives

In order to meet specific physical and chemical properties, various auxiliary components added are called additives. For example, curing agents are added to form a network or body structure of the main adhesive and increase the cohesive strength of the adhesive layer (they react with the main adhesive and produce cross-linking effects); Adding curing accelerators or catalysts to accelerate curing and reduce reaction temperature; In order to improve the resistance to atmospheric aging, thermal aging, arc aging, ozone aging and other properties, anti-aging agents are added; Adding fillers to give adhesives specific properties and reduce costs; Adding toughening agents to reduce the rigidity of the adhesive layer and increase toughness; In order to improve processability, reduce viscosity, and extend service life, diluents are added. include:

1) Curing agent

Curing agent, also known as hardener, is a component that accelerates the curing of bonding substances through chemical reactions. It is the most important component in adhesives. Its function is to directly or through a catalyst react with the main polymer, and after curing, introduce the curing agent molecules into the resin, transforming the originally thermoplastic linear main polymer into a tough and hard network structure.

There are many types of curing agents, and different resins and requirements require different curing agents to be used. The processability and performance of adhesive bonding are determined by the performance and quantity of the curing agent added.

2) Toughening agent

The active groups of toughening agents directly participate in the curing reaction of adhesives and enter the chain structure of a large molecule ultimately formed in the cured product. After curing, adhesives without toughening agents have brittle properties, are prone to cracking, and have poor practicality. Adhesive agents with toughening agents have good impact strength and peel resistance. Different toughening agents can also reduce their internal stress and curing shrinkage to varying degrees, and improve their low-temperature performance.

Common toughening agents include polyamide resin, synthetic rubber, aldehyde resin, polysulfone resin, etc.

3) Diluent

Diluents, also known as solvents, are mainly used to reduce the viscosity of adhesives, increase their wetting ability, and improve process performance. Some can reduce the activity of adhesives, thereby extending their service life. However, excessive addition can reduce the bonding strength, heat resistance, and medium resistance of the adhesive.

Common diluents include acetone, paint, and other solvents that are compatible with adhesives.

4) Packing material

Fillers generally do not undergo chemical reactions in adhesives. The use of fillers can improve the strength, impact toughness, wear resistance, aging resistance, hardness, maximum operating temperature, and heat resistance of adhesive joints, while reducing linear expansion coefficient, curing shrinkage rate, and cost. Common fillers include copper oxide, magnesium oxide, silver powder, porcelain powder, mica powder, asbestos powder, talc powder, etc.

5) Modifier

Modifiers are components added to improve a certain aspect of adhesive performance to meet special requirements. For example, coupling agents can be added to increase bonding strength, as well as preservatives, mold inhibitors, flame retardants, and stabilizers.

IIWhat is silicone thermal conductive sealant (adhesive)?

Can sealing adhesive, also known as electronic potting adhesive, is a widely used term for bonding, sealing, potting, and coating protection of electronic components. Before curing, sealant belongs to a liquid state and has fluidity. The viscosity of the sealant varies depending on the material, performance, and production process of the product. The sealing adhesive needs to be completely cured before it can realize its practical value. After curing, it can play a role in waterproofing, moisture-proof, dustproof, insulation, thermal conductivity, confidentiality, anti-corrosion, temperature resistance, and shock resistance. There are many types of electronic potting adhesives, and there are three common types based on material types: epoxy resin potting adhesive, silicone resin potting adhesive, and polyurethane potting adhesive.

Sealing is the process of mechanically or manually filling liquid composite materials into devices containing electronic components and circuits, and curing them into high-performance thermosetting polymer insulation materials at room temperature or under heating conditions. Its function is to enhance the overall integrity of electronic devices and improve their resistance to external impacts and vibrations; Improving the insulation between internal components and circuits is beneficial for miniaturization and lightweighting of devices; Avoid direct exposure of components and circuits, and improve the waterproof and moisture-proof performance of devices. Organic silicone sealant has a wide range of applications, varying technical requirements, and a wide variety of varieties. There are two types of curing conditions: room temperature curing and baking curing.

• Characteristics of Thermal Conductive Sealing Adhesive

Thermal conductive sealing adhesive is a type of silicone thermal conductive sealing adhesive that can reliably maintain sensitive circuits and components for a long time. It has excellent electrical insulation function, can withstand environmental pollution, and avoid the harm caused by stress, shock, humidity and other environmental factors to the product. It is particularly suitable for products that require good heat dissipation for sealing materials. Thermal conductive sealant has excellent physical and chemical resistance properties.

Thermal conductive sealant has outstanding thermal conductivity and flame retardancy, low viscosity, good leveling properties, and solidifies into a soft rubber like structure. It has good impact resistance, strong adhesion, insulation, moisture resistance, earthquake resistance, corona resistance, electrical leakage resistance, and chemical medium resistance.

• Typical Applications of Thermal Conductive Sealing Adhesive

Thermal conductive potting adhesive is suitable for insulation and thermal sealing of electronic, power modules, high-frequency transformers, connectors, sensors, electric heating parts, and circuit boards. It is also used for industrial electronic components such as LED displays, power supplies, electrical appliances, backlight cooling modules, sealing, packaging protection, and insulation moisture-proof.