In flame-retardant polyvinyl chloride and flame-retardant polyethylene, antimony trioxide is a particularly high-quality flame retardant. Due to its excellent flame-retardant synergistic effect with halogens, it can enhance the oxygen index of the material and the self-extinguishing performance of the raw material when away from the fire.
However, many material manufacturers use cheap, counterfeit and substandard antimony trioxide labeled as "arsenic trioxide, also known as arsenic trioxide" to deceive many optical and electrical cable factories. Antimony trioxide is produced by calcining stibnite (Sb2O3) and oxidizing it to produce Sb2O3. Arsenic and iron are removed through purification, with only carbon converted into metallic antimony. Further smelting and purification are carried out, and then pure Sb2O3 is obtained through oxidation. Antimony and arsenic are buddy minerals, so they must be refined repeatedly to remove arsenic.
At present, the arsenic content of high-purity antimony trioxide in Chinese mainland is controlled at ≤300ppm. However, antimony trioxide that has not undergone repeated refining also has a large market, which is attributed to its low price! Currently, antimony trioxide with a purity of around 99.5% in the market is priced at approximately 55,000 yuan per ton, while the unrefined, plain antimony trioxide only costs 15,000 yuan per ton, with a market price difference of nearly four times.
If the 5% proportion in the secret recipe is inserted, not only the material itself but also the price will be 2,000 yuan per ton apart. However, this is by no means the terrifying point of passing off inferior goods as good ones. A truly terrifying act is far more serious!
What is arsenic trioxide? The following is quoted from Sogou Baike: "Arsenic trioxide, commonly known as arsenic trioxide, with the chemical formula As2O3, is a socially valuable arsenic compound and an important raw material for arsenic chemistry." It is also one of the long-standing radioactive substances, odorless and tasteless, and appears as white, frost-like fragments, hence the name arsenic. It is a highly carcinogenic by-product formed during the operation of various specific ores, such as gold mining, high-temperature distillation of arsenopyrite (toxic sand) and condensation of its white smoke, etc."
It is obvious that arsenic trioxide has been strictly prohibited by REACH, but this toxic raw material is still adopted by most raw material manufacturers in Chinese mainland. Many cable manufacturers' unclear application and purchase standards that do not comply with various environmental protection regulations have resulted in harm and risks to grassroots workers and society.
Second, the so-called low smoke zero halogen flame retardant materials, also known as certain flame retardant materials that do not contain halogens and produce little smoke. Basic flame retardants include aluminium hydroxide, magnesium hydroxide and phosphorus-nitrogen type flame retardants, etc. They are not flame retardants containing halogens or other heavy metal salts.
However, the quality of the raw materials currently used in China varies greatly. It is no longer just that they fail to meet the physical property requirements. In fact, the vast majority of wire protection sleeves use non-flame-retardant calcium carbonate as the filling material or directly utilize recycled low-smoke and halogen-free waste materials.
The optical cables produced with this material feature excellent flame retardancy, very little smoke when ignited, and no release of corrosive gases. Therefore, they are widely used in nuclear power plants, light rail passenger stations, telephone exchanges and computer control bases, multi-story buildings, shopping centers, hotels, radio and television stations, major military facilities, petrochemical platforms, etc., where various types of workers are concentrated. In situations with low air density.
The halogen-free and low-smoke characteristics of optical cables, when a fire occurs, cause slow diffusion, low smoke concentration, high visibility, and small release of harmful substances, which is conducive to the evacuation of employees. However, the materials currently used in China vary greatly in quality. Not only do they fail to meet the physical property standards, but the vast majority of sheaths are filled with non-flame-retardant calcium carbonate or directly use recycled low-smoke and halogen-free materials.
At present, it is understood that the types of optical cables involving the application of recycled materials and calcium carbonate filling instead of flame retardant sheaths mainly include: butterfly-shaped optical cables, low-voltage cables, video cables, railway signal cables, etc. It is mainly used in places such as tracks or indoor buildings. The sheath material filled with calcium carbonate is not only not flame-retardant, but sometimes also flammable, and thus cannot meet the requirements of flame spread speed and smoke emission during combustion. The fundamental approach is to cut costs for the sake of profit and show no concern for the quality of the project.
The service life of optical cables with recycled plastics as sheaths needs to be evaluated. One of the major hazards is that they are prone to aging and cracking, which cannot provide reasonable protection for the core of the optical cables and significantly reduces their service life.
Third, otherwise, say polyethylene recycled materials. Recycled materials themselves are made from discarded products under the guise of environmental protection. Not to mention the harm caused by such application in the field of market order, just the commodity itself has incalculable harm. Even if additives are added again, the defects caused inside the material cannot be reversed. Therefore, its service life will be much shorter than that of brand-new materials, and it may even age and crack in a short period of time.
When it comes to recycled materials, people always ask what the difference is between brand-new materials and recycled materials? Recycled materials are made by recycling and crushing plastic products and scraps, adding additives, and then re-granulating them.
Due to the uncertainty of the origin of plastic products and scraps, there are many impurities contained in them, the quality is very unstable, and the physical properties vary greatly among batch numbers. In terms of mechanical and electrical properties such as tensile strength and toughness, it is inferior to brand-new materials. The product color will also be darker and dull, with poor gloss. Most recycled materials have a pungent smell, some have a strong odor similar to that of detergent, and some have a pungent smell.