In the metal composite decorative material industry, when fluorocarbon coatings are mentioned, everyone's first reaction is PVDF fluorocarbon resin coatings. As the most widely used and mature coatings in the industry, PVDF fluorocarbon coatings have excellent weather resistance and other indicators. However, the sharp rise of PVDF resin since last year has made the supply of PVDF fluorocarbon coatings tight and the price increased. As another product of the fluorocarbon family, FEVE fluorocarbon coatings have begun to appear in everyone's field of vision. Here, we will take you to a new understanding of FEVE fluorocarbon coatings.
Figure / The demand for PVDF for lithium batteries in new energy vehicles is blowing out, resulting in a serious shortage of PVDF resin
Maybe everyone has doubts at the beginning, PVDF and FEVE are both called fluorocarbon coatings, so what exactly is fluorocarbon?
The first "fluorocarbon coating" was born in 1938. The polytetrafluoroethylene resin synthesized by DuPont in the United States has excellent weather resistance, heat resistance, chemical resistance and non-stick properties; The commercialization of tetrafluoroethylene (PTFE) and the development of the first fluorine-containing coating product, Teflon, requires baking at 420°C to form a film. Teflon (Teflon) is mainly used in non-stick pan coating, polymerization reactor lining, etc.
Figure / Teflon non-stick coating
In 1965, Pennwalt and Elf Altochem of the United States successfully developed Kynar500 polyvinylidene fluoride (PVDF) coating. Its quality standard is the well-known AAMA2605 high performance coating standard. Widely used in the field of architectural aluminum curtain wall, it has excellent aging resistance, chemical resistance and other properties, but cannot be cured at room temperature, and must be baked at 240 ℃ to form a film. After years of development, PVDF fluorocarbon coatings have become The most widely used and mature coating system in the industry.
Figure /PVDF fluorocarbon resin coating
In 1982, Japan's Asahi Glass Co., Ltd. successfully developed Lumiflon polychlorotrifluoroethylene copolymer resin (FEVE) room temperature curing fluorocarbon coatings. The coating has high gloss, high transparency, is soluble in conventional organic solvents, and can be cross-linked and cured at room temperature, enabling fluorocarbon coatings to be applied to PVC profiles, plastic-steel profiles, glass fiber reinforced plastics, steel structures and other materials, expanding the application field. Because FEVE fluorocarbon coatings can be cured at room temperature and high temperature, they are not restricted by construction conditions. They have been widely used in outdoor walls, heavy anti-corrosion of steel structures and other fields in the past two decades, and the application effect is good. Just because the price is relatively high, it has not been widely used in the metal decoration material industry.
Figure / Application of FEVE coating on Akashi Kaikyo Bridge
Figure / 30 years of FEVE coatings application case - Hiroshima Tokiwa Bridge
Starting from 2021, with the blowout of demand for PVDF resin for lithium batteries, the price of 142b resin, the upstream raw material of PVDF, has skyrocketed, resulting in a sharp rise in the price of PVDF fluorocarbon coatings and a serious shortage of supply. In the current market, the comprehensive cost of FEVE fluorocarbon coatings already has a certain price advantage compared to PVDF fluorocarbon coatings, which also provides an opportunity for the application of FEVE fluorocarbon coatings.
FEVE fluorocarbon resins are copolymers formed from fluorine monomers and vinyl ether or vinyl ester monomers. According to different comonomers, FEVE fluorocarbon coatings are divided into different types: according to the type of fluoromonomer, it can be divided into two types: chlorotrifluoroethylene type and tetrafluoroethylene type; according to the type of comonomer, it can be divided into ethylene There are two types of base ethers and vinyl esters, no matter what kind of coating it is, the factor that determines the high durability of the resin is the ultra-high bond energy between fluorine-carbon elements.
Figure / The ultra-high bond between C-F elements can ensure the stability of the resin
Compared with PVDF fluorocarbon coatings, the main features of FEVE fluorocarbon coatings are as follows:
1. FEVE coating has a lower curing temperature of 216~224℃, which can save more energy consumption;
2. The solid content of the coating can reach more than 70%, and the VOC (≤420g/L) emission during the coating process is lower, which is more in line with environmental protection requirements;
3. FEVE coating has high gloss and high hardness, so it is more suitable for aluminum veneer products sprayed after bending;
It can be seen from the above indicators that the application of FEVE coatings meets the current national development requirements for low-carbon environmental protection, energy conservation and emission reduction. A few days ago, Zhejiang has issued the "Zhejiang Province "14th Five-Year Plan" Volatile Organic Compound Comprehensive Management Plan, which requires the development of low-VOC coatings replacement. It can be said that the use of more environmentally friendly coatings has become the general trend.
As we all know, the weather resistance of PVDF fluorocarbon coatings has passed the test of time in the metal decoration material industry. Although FEVE fluorocarbon coatings also have their corresponding applications, they are relatively complex because of their trifluoro and tetrafluoro, ethers and esters. The classification of metal decoration materials and their different types of weather resistance have also brought trouble to the application of downstream metal decoration material enterprises.
To this end, the Metal Composites Branch and China National Testing and Testing Holding Group Co., Ltd. plan to jointly carry out a comparison test of durability of FEVE coated aluminum sheet products and PVDF fluorocarbon coated aluminum sheet products, through laboratory acceleration and durability under natural conditions System test to comprehensively compare the durability characteristics of FEVE coated aluminum sheet products and environmentally friendly PVDF fluorocarbon coated aluminum sheets. The specific comparison test plan will be announced soon.
