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Functions and roles of different PP types in PCB

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In PCB (Printed Circuit Board) manufacturing, PP (Prepreg) is a key material, which consists of a reinforcing material (usually glass fibre cloth) impregnated with a resin (usually epoxy resin) and is used for the inner insulation and bonding of multi-layer PCBs. Different PP types have different characteristics and functional roles. The following are some common PP types and their functional roles:

FR-4 PP: 

This is the most common type of PP with good mechanical strength and electrical properties for most standard PCB applications.

High TG (Glass Transition Temperature) PP: 

This type of PP has a high glass transition temperature and is suitable for applications that require good performance at high temperatures, such as automotive electronics and certain industrial equipment.

High-speed PP: 

This type of PP is suitable for PCBs with high-speed signal transmission and typically has a low dielectric constant (Dk) and dielectric loss (Df), which helps to reduce signal transmission delays and improve signal integrity.

Low Loss PP: 

Suitable for radio frequency (RF) and microwave circuit boards, this PP has very low dielectric loss, which helps to reduce signal loss during transmission.

Flexible PP: 

Used in the manufacture of flexible PCBs, this PP has good flexibility and bending resistance and is suitable for electronic devices that need to be bent or folded.

Halogen-free PP: 

This type of PP does not contain halogens and is suitable for applications with higher requirements for environmental and human safety, such as certain medical devices and consumer electronics.

High Thermal Conductivity PP: 

With high thermal conductivity, this PP helps dissipate heat from the PCB and is suitable for applications with high thermal loads such as power electronics and LED lighting.

Metal-based PP: 

This type of PP combines the properties of metal substrates (e.g. copper, aluminium) and PP for better thermal management and electromagnetic shielding.


PP using polytetrafluoroethylene (PTFE) as a base material has very high chemical stability and non-adhesive properties for PCBs in special environments.

Special Reinforcement PP: 

In addition to glass fibre cloth, PP can be manufactured using other reinforcement materials (e.g. carbon fibre, aramid, etc.) to meet specific performance requirements.


PP (Prepreg, prepreg) plays multiple important roles in PCB (Printed Circuit Board) manufacturing, its main roles include:


PP acts as an inner insulating material to prevent electrical shorts between different conductive layers.


The resin contained in PP acts as an adhesive during the hot-press curing process, firmly bonding the different copper foil layers (conductive layers) together to form a multi-layer PCB structure.

Providing Mechanical Support: 

PP reinforcements (e.g. glass fibre cloth) provide the mechanical strength and rigidity required by the PCB, resulting in better stability during assembly and use.

Thermal Management: 

Certain special types of PP (e.g. high thermal conductivity PP) help to dissipate heat from the PCB by conducting heat away from the heat source to the outside of the PCB through the thermal conductivity properties of the resin and reinforcement materials.

Electromagnetic Compatibility (EMC): 

PP can be used as part of the PCB to help reduce electromagnetic interference (EMI) and improve electromagnetic compatibility.

Chemical Stability: 

PP materials usually have good chemical stability and are resistant to chemicals and are suitable for a wide range of environmental conditions.

Dimensional Stability: 

PP provides good dimensional stability during PCB manufacturing, reducing the effects of thermal expansion and contraction on board performance.

Improved Reliability: 

By using PP, PCBs can withstand higher temperatures and mechanical stresses, thus improving the reliability and lifetime of the entire electronic assembly.

Adaptable to Different Processing: 

PP can be customised for different PCB processing (e.g. drilling, laminating, etching, etc.) to meet specific manufacturing needs.

Environmentally Friendly: 

Some types of PP (e.g. halogen-free PP) are halogen-free, helping to reduce the environmental impact during PCB disposal.

PP is an indispensable material in PCB manufacturing, and its diverse functional roles ensure the quality and performance of PCBs and meet the diverse needs of electronic devices for circuit boards.

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