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Halogen free PCB-special and environmentally friendly PCB

Halogen free PCB-special and environmentally friendly PCB

Halogen-free boards are environmentally friendly materials. Halogen-free PCB is the substrates used that are processed with halogen-free raw materials. Halogen-free PCB usually has good heat dissipation reliability and is more suitable for high-temperature processes required by lead-free circuits. It also maintains signal integrity due to its low dielectric constant. Therefore, the demand for halogen-free PCB has been increasing.

What is halogen-free PCB?

PCBs are deemed to be “halogen-free” if they contain fewer than 900 parts per million (ppm) of either chlorine or bromine and less than 1500 parts per million (ppm) of halogen equipment as a whole. Examples of halogens that are extremely hazardous to living beings are chlorine, bromine, fluorine, iodine, and astatine. Chlorine is the most toxic of the halogens. Because they have lower concentrations of these potentially hazardous components, halogen-free PCB, often known as “Hal-Free” PCBs, are frequently utilized in construction and industry.

What elements are halogens?

The halogen group elements refer to the elements of group VIIA of the periodic system,
and includes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and Ishida (Ts).When coupled with metals, halogens produce salts. Because their outer shells only contain 7 electrons, all the halogens have an oxidation number of -1. As a result of this quality, they are more reactive than the other non-metal groups. The three halogen phases can be accessed at room temperature.

Where are halogen used in PCB?

In the case of PCB, halogens are adaptable enough to be used in a number of different contexts. Chlorine can be added to polyvinyl chloride (PVC) wires in order to provide either a protective coating or a flame retardant. In addition, it is used as a solvent in the production of semiconductors and in the cleaning of computer chips. Both of these processes take place in the computer industry. Bromine is a versatile element that can be used to protect electronic components in a variety of ways, including as a sterilant and as a flame retardant.

What is the features of halogen-free PCB?

What is the features of halogen-free PCBHalogen-free PCB is becoming more and more common as a direct result of the increasing demand for halogen-free components in electronic goods. The materials that are used in conventional printed circuit boards and those that are used in halogen-free printed circuit boards are different from one another in terms of the dielectric constant, the dissipation factor, and the moisture diffusivity. PCBs that do not include halogens are best bet if one is searching for an ecologically friendly solution for the product that he/she is developing, as this need must be satisfied.
1. Insulation of materials

Due to the use of P or N to replace the halogen atoms, the polarity of the molecular bond segment of the epoxy resin is reduced to a certain extent, thereby improving the qualitative insulation resistance and breakdown resistance.

2. Water absorption of the material
The water absorption of halogen-free sheets is lower than that of conventional halogen-based flame retardant materials. For the sheet, low water absorption has a certain influence on improving the reliability and stability of the material.

3. Thermal stability of the material
The content of nitrogen and phosphorus in the halogen-free sheet is greater than that of ordinary halogen-based materials, so its monomer molecular weight and Tg value are increased. In the case of heating, its molecular mobility will be lower than that of conventional epoxy resins, so the thermal expansion coefficient of halogen-free materials is relatively small.

what’s the application of halogen-free PCB?

what's the application of halogen-free PCBIn any application that calls for traditional printed circuit boards, halogen-free PCB can be used in their place. halogen-free PCB are widely used in substations, power stations, power distribution rooms, laboratories and outdoor electrical work and other applications. This covers automation in the industrial sector as well as consumer electronics. PCBs that do not contain any halogens are completely effective and can be utilized for a broad number of applications.

Nevertheless, the specifications for these PCBs are slightly different from those of PCBs that comprise components like chlorine and bromine. For example, the thermal expansion coefficient for halogen-free PCB has a smaller range than for PCBs containing chlorine and bromine. As a result, thermal expansion coefficients that fall outside of the permissible range have to be calculated precisely in order to ensure the necessary mechanical stability and structural integrity of the PCB.

what’s the difference between halogen-free PCB and normal PCBs

what's the difference between halogen-free PCB and normal PCBsIn terms of their ability to provide dependable electrical insulation, PCB substrates that do not contain halogens are preferable. As a result, the polarity of substances that do not contain any halogens is lower than that of those that contain bromine. Halogen-free PCB has a higher resistance to the flow of electrical current as a consequence of this. PCBs that don’t contain any halogens have a lower thermal expansion coefficient, for the same reason.

Therefore, printed circuit boards (PCBs) that do not include halogens are less prone to overheat and have a smaller thermal expansion compared to their counterparts that do contain halogens. Halogen-free printed circuit boards (PCBs) have a higher glass melting point (TG), which makes them more robust and suited for use in high-temperature and high-power environments. Last but not least, halogen-free PCB has a lower moisture absorption rate.

About halogen-free PCB legislation

IEC 61249-2-21 and JPCA-ES-01-2003 mandate that halogen-free copper clads contain no more than 0.09 wt% (weight percent) (900 ppm) of chlorine (Cl) and 0.15 wt% (weight percent) (150 ppm) of bromine (Br) (1500ppm). Because of this, we are able to define halogen-free PCB as printed circuit boards that have chlorine levels that are less than 0.09 weight percent (900 parts per million), bromine levels that are less than 0.09 weight percent (900 parts per million), and the total amount of halogens that are less than 0.15 weight percent. Halogen-free PCB are also known as halogen-free printed circuit boards (1500ppm).

FAQ about halogen-free PCB

Why is halogen bad for the environment

Why is halogen bad for the environment?

The lungs and other organs can be damaged by prolonged exposure to halogens like chlorine and bromine, which can occur in the environment or in the workplace. Inhaling chlorine gas can cause serious health issues, including asthma, bronchitis, pneumonia, and acute respiratory distress syndrome (ARDS).

The inhalation of bromine can cause bronchospasm, airway hyperresponsiveness, acute respiratory distress syndrome (ARDS), and even death. This occurs despite the fact that bromine is less reactive and has a lower oxidation potential than chlorine. It has been demonstrated that both halogens are harmful to the cardiovascular system and can cause damage to the heart.

Is FR4 halogen-free?

The conventional FR4 printed circuit boards, which make use of tetrabromobisphenol A flame retardant causes the release of a trace amount of HBr (hydrogen bromide). When they are burned, a significant amount of smoke that is brominated is produced. FR4 PCB may be used, despite the fact that they do contain halogens; nonetheless, these PCBs do not lack halogens.

Is halogen free mandatory?

The absence of halogens from the product is optional. However, there are standards that can serve as guides. For instance, the IEC 61249-2-21 standard for PCBs sets maximum allowable levels of bromine (900 ppm) and chlorine (900 ppm) by weight of PCB material, with a combined maximum of 1500 ppm. If the limits are not exceeded, the supplier can label the product as “halogen-free”.

PCBs are used in most electronic products in our lives, which promotes electronics, but also pollutes the environment due to waste. The use of halogen-free PCB can greatly alleviate this problem. In addition, it has many advantages in material and manufacturing process compared to halogen-free PCB.

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