What does halogen-free in circuit boards mean? You know what?

What does halogen-free in circuit boards mean? You know what?

PCB manufacturers, PCB designers and PCBA manufacturers explain to you what halogen free PCB means? You know what?

Halogen free circuit board, that is, the substrate used is processed from halogen-free raw materials

Halogen-free 

Many customers will require halogen-free when making boards. Halogen free boards are environment-friendly materials. Halogen free circuit boards are made of halogen-free raw materials.

Electronic equipment contains specific materials that contain the highest concentrations of halogens. In order to create halogen-free circuit boards in electronic equipment printed boards, it is necessary to replace some materials or reduce their use on boards. It is also necessary to determine the halogen-free content in the circuit. Some alternatives require special design considerations, which ultimately need to be considered.

At present, most halogen-free plates are mainly phosphorus and phosphorus nitrogen systems. When burning, the phosphorus containing resin is decomposed by heat to generate metapolyphosphoric acid, which is highly dehydrated, forming a carbonized film on the surface of the polymer resin, isolating the contact between the resin burning surface and the air, so that the fire can be extinguished to achieve flame retardant effect. The high polymer resin containing phosphorus and nitrogen compounds produces incombustible gas when burning, helping the resin system to be flame retardant. So, what are the characteristics of halogen-free plates?

1. Insulation of materials

Because the halogen atom is replaced by P or N, the polarity of the molecular bond segment of the epoxy resin is reduced to a certain extent, thus improving the insulation resistance and anti breakdown ability.

02 Water absorption of materials

Ostensive effect

Halogen free plates have less N and P electrons in nitrogen phosphorus redox resin than halogen, and the probability of forming hydrogen bond with hydrogen atom in water is lower than that of halogen materials, so the water absorption of the materials is lower than that of conventional halogen flame retardant materials. For plates, low water absorption has a certain impact on improving the reliability and stability of materials.

03 Thermal stability of materials

The content of nitrogen and phosphorus in halogen-free plate is higher than that of halogen in common halogen-free materials, so the molecular weight and Tg value of monomer are increased. When heated, its molecular mobility will be lower than that of conventional epoxy resin, so the thermal expansion coefficient of halogen-free materials is relatively small.

Halogen free demand is growing

Compared with halogen-containing plates, halogen-free plates have more advantages. It is also a general trend for halogen-free plates to replace halogen-containing plates. At present, there are many kinds of halogen-free solder resist inks on the market, and their performance is similar to that of ordinary liquid photosensitive inks, and their specific operation is basically similar to that of ordinary inks.

Halogen free circuit boards usually have good heat dissipation reliability and are more suitable for the high-temperature process required by lead-free circuits. Because of its low dielectric constant, it can maintain signal integrity. Therefore, the demand for halogen-free circuit boards is growing.

PCB manufacturers, PCB designers and PCBA manufacturers explain to you what halogen free PCB means? You know what?