In flame retardant polyvinyl chloride and flame retardant polyethylene, antimony trioxide is a very efficient flame retardant because it has a good flame retardant synergistic effect with halogen, which can improve the oxygen index of the material. The self-extinguishing performance of the material.
At present, the arsenic content of high-purity antimony trioxide in China is controlled at ≤300ppm, but there is also a large market for antimony trioxide without repeated purification, because it is cheap! At present, the purity of more than 99.5% of the market is more than 55,000 yuan / ton, and the so-called antimony trioxide has not been purified, the price is only 15,000 yuan / ton, the price difference is nearly four times.
If you add 5% of the formula, only the price of this kind of material will be 2,000 yuan / ton, but this is not a terrible point of cutting corners. The real terrible thing is to be much more serious!
What is arsenic trioxide? The following quoted from wikipedia: "Arsenic trioxide, commonly known as arsenic, molecular formula As2O3, is the most commercially valuable arsenic compound and the main arsenic chemical starting material. It is also one of the oldest poisons, odorless and tasteless, the appearance of white creamy powder It is called arsenic. This is a highly toxic by-product produced by certain specified mineral treatment processes, such as gold mining, high-temperature distillation of arsenopyrite (toxic sand) and condensation of white smoke."
As we all know, arsenic trioxide has long been banned by REACH, but such toxic raw materials are still used by most domestic material manufacturers. Many cable manufacturers do not know the use, the procurement standards do not require environmental protection, in exchange for the damage and hidden dangers of front-line personnel and society.
the so-called low-smoke halogen-free flame retardant material refers to a flame retardant material that does not contain halogen and has a small amount of smoke. Conventional flame retardants include aluminum hydroxide, magnesium hydroxide, and phosphorus-nitrogen flame retardants, and do not contain halogen and other heavy metal salt flame retardants.
However, the quality of materials used in China is uneven. It is not only unable to meet the requirements of physical properties, but even most of the jackets use non-flame-retardant calcium carbonate as a low-smoke halogen-free waste material that is filled or directly recycled.
The optical cable produced by using this material has the characteristics of superior flame retardancy, less smoke during combustion, and no corrosive gas escape, so it is widely used in nuclear power plants, subway stations, telephone exchanges and computer control centers, high-rise buildings, Shopping malls, hotels, radio and television stations, important military facilities, oil platforms, etc., as well as places where people are concentrated and air density is low.
The halogen-free low-smoke, low-halogen and low-smoke characteristics of the optical cable, when the fire occurs, the spread speed is slow, the smoke concentration is low, the visibility is high, and the release amount of harmful gas is small, which is convenient for personnel to evacuate. However, the materials currently used in China are uneven, and it is not only unable to meet the physical requirements, but even most of the jackets use non-flame-retardant calcium carbonate as a filling or direct use to recycle low-smoke halogen-free materials.
It is currently known that optical cable types involving the use of recycled materials and calcium carbonate filling instead of flame retardant sheaths are mainly butterfly optical cables, low voltage cables, video cables, railway signal cables, and the like. Mainly used in places such as rails or indoor buildings. The use of calcium carbonate as a filling sheathing material is not only flame retardant, but also has flammable characteristics, and it is unable to meet the requirements of the flame spread speed and the amount of smoke generated by the combustion. It is entirely for the benefit of reducing costs, regardless of the quality of the project.
The use of recycled plastic as a sheathed optical cable, the service life needs to be evaluated, the biggest hazard is easy aging cracking, can not effectively protect the cable core of the optical cable, so that the service life of the optical cable is greatly reduced.
let's talk about polyethylene recycled materials. The recycled material itself is in the name of environmental protection, using waste products. Regardless of the impact of such use on market order, there is a huge risk in the product itself. Even if the additive is added again, it cannot compensate for the defects generated inside the material, so the service life will be much lower than the new material, and even the aging cracking will occur in a short period of time.
When it comes to recycled materials, everyone always asks what is the difference between new and recycled materials? The recycled material is recovered from plastic products, corner scraps, added with additives, and regranulated.
Because of the uncertainty of the source of plastic products and corner scraps, the impurities contained therein are numerous, the quality is very unstable, and the physical properties between batches are large; the mechanical strength and electrical properties such as tensile strength and toughness are far less than the new materials; The color of the product will be darker, dull and the gloss is poor; most of the recycled materials have an odor, some are similar to the rich taste of detergent, and some are pungent.
In addition to the difference in performance of these materials, the biggest difference is in use. Because the recycled materials contain more impurities, non-decomposable inorganic substances, etc., the surface of the product will be rough, matt, or even granules after extrusion. Compared with the smooth and delicate surface of the new material, it has a serious impact on the appearance of the product. .
The oxidation induction period is an index for evaluating the heat-resistant degradation ability of materials during processing, storage and use. The differential thermal analysis method is used to test the accelerated aging degree of plastics in high-temperature oxygen based on the exothermic reaction when plastic molecular chains are broken.
However, due to the inconsistency of the source and the characteristics of multiple processing, the molecular chain has been partially broken. Even if the additive is added again, it cannot compensate for the defects generated inside the material, so the service life will be much lower than the new material, and even There will be aging cracking in the short term.
soft PVC material has good electrical and mechanical physical and electrical properties, wide resources, low price and is widely used in all kinds of wire and cable and optical cable. However, in the past ten years, some cable material enterprises have used low-quality, low-cost so-called substitute plasticizers to produce low-cost PVC cable materials that do not meet the standard requirements.
The most used PVC cable material is the so-called epoxy fatty acid methyl ester, which is an epoxy "ditch oil", which is a chemical product obtained by oxidation treatment of various types of trench oil. What is the result of its addition to the cable material, and what are the hazards to the performance of the material and the long-term use of the cable?
Epoxy fatty acid methyl ester, which has a flash point of 170 to 190 ° C, has certain compatibility with PVC resin. There is a great risk of precipitation after adding PVC, which is characterized by summer oil and winter frost. According to different formulas and processing techniques, the precipitation time is also different, some have performance in one or two months, and some may only be expressed in one, two, or even several years.
Cables made of such materials will continue to find oil and white when the laying time increases. In addition, as the component of the addition increases, it is easy to cause the quality loss of the heat aging to be unqualified, and the large amount of the addition causes serious failure.