By：PCBBUY 07/23/2021 17:32
Like the RoHS lead free requirements, halogen free standards require CMs to use new materials and manufacturing methods. The IEC defines halogen free as < 900 ppm of chlorine and bromine and < 1500 ppm total halogens, while the RoHS has its own limits.
Now why is “halogen free” in quotations? It’s because meeting the standard doesn’t necessarily guarantee your board has no halogens in it. For example, the IPC specifies tests for detecting halogens in PCBs, and these tests generally detect ionically bonded halogens. However, most of the halogens found in fluxes are covalently bonded so the test won’t detect them. This means that to make a truly halogen free board, you’ll need to go beyond what the standards specify.
In this passage, we will provide every detail of halogen-free PCB. Please check and read the content below to learn more professional information.
What are the advantages of halogen-free PCB?
What are the benefits of using halogen-free PCBs? First, it's important to understand that halogen is not a material in itself. It is a way to describe a class of elemental gases, including fluorine, chlorine, bromine, iodine and astatine. While PCBs containing halogen gases are generally safe, these elements are toxic and can cause reactions from blurred vision and nausea to difficulty breathing and a burning sensation in the eyes, nose and throat.
When a PCB is eventually disposed of, the disposal process can potentially release these elements into the environment, polluting the atmosphere. In fact, the incineration of halogen-based components can produce dioxin, which the EPA defines as one of the most toxic chemicals known to man. In fact, the EPA has confirmed inhaling dioxin is even small doses will almost invariably lead to cancer and ultimately death.
The significant benefit of halogen-free boards is that they do not pose the same threat to the environment, which can be great for environmentally-conscious companies and environmentally-conscious consumers who patronize those companies.
What are the applications of halogen-free PCB?
What types of industries and applications are halogen-free PCBs typically used in? Halogen-free PCBs can be used in any industry or application where you would use electronic PCB boards, from consumer electronics to industrial automation and everything in between. While there is some variance in the specifications of halogen-free PCBs compared to PCBs which contain chemicals like chlorine and bromine, these boards are entirely effective and suitable for most applications.
If you're concerned about how halogen-free boards will work with your specific application but would still like to try them, feel free to give us a call to discuss the issue. Our PCB experts will be more than happy to talk to you about the differences between halogen-free PCBs and other printed circuit boards, as well as how those differences may or may not affect your specific product.
Although all companies can make use of halogen-free PCBs, they appear most often in companies made a forward commitment to being better to the environment, reducing their carbon footprint and being responsible about the toxins they emit into the atmosphere as a result of their production processes.
What are the technologies of halogen-free PCB?
As an important characteristic of the coating material, it is necessary to maintain sufficient softness while ensuring the flame retardancy. In order to ensure this softness, elastomer is usually introduced into the epoxy resin. However, doing so will have a more serious consequence, that is, the flame retardancy will become worse. Therefore, to solve this problem, researchers usually take the following measures.
(1) Phosphorous flame retardant is adopted. For example, the use of phosphate ester flame retardant, in the combustion of it can promote dehydration carbonization reaction, so that the surface of the material formed a layer of carbonization film, cut off the contact with oxygen, so that it is difficult to burn.
(2) Adopt nitrogen-containing flame retardant. Nitrogen atoms are introduced into the molecular structure of the resin to generate an inert gas to oxygen during combustion.
(3) Adopt inorganic flame retardant. For example, the addition of magnesium hydroxide, aluminum hydroxide and other inorganic filler, they release crystal water in the combustion, reduce the combustion temperature, thereby inhibiting the combustion.
(4) Resin with special structure is used. For example, epoxy resin containing phenyl alkyl is used in the resin combination.
What is coating material of halogen-free PCB?
The so-called coating material is a film forming material that is coated on the surface of the graph of flexible PCB to protect it, which is an indispensable basic material for flexible printed circuit board. In recent years, due to the requirements of environmental protection, a number of different varieties and types of halogen-free coating materials have been listed, but in terms of insulation reliability, peeling strength and other aspects are not as good as the original (that is, halogen as a flame retardant agent) coating materials.
In view of the current situation of coating materials used in flexible printed circuit boards, researchers have determined the following research directions: first, the need for halogens; Secondly, as a coating material to ensure that it has enough insulation reliability and enough strength; Furthermore, as a coating material, it must be kept soft; In addition, its fluidity must be controlled to ensure the desired thickness on the circuit surface.
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