What are some epoxy resin curing agents used in the wind power industry?
In the wind power industry, epoxy resin is currently widely used in wind turbine blade materials. Epoxy resin is a high-performance material with excellent mechanical properties, chemical stability, and corrosion resistance. In wind turbine blade manufacturing, epoxy resin is widely used in structural components, connectors, and coatings. In the blade’s support structure, frame, and connectors, epoxy resin provides high strength, high stiffness, and fatigue resistance, ensuring the blade’s stability and reliability.
Epoxy resin can also improve the blade’s wind shear resistance and impact resistance, reduce blade vibration and noise, and improve wind power generation efficiency. Currently, there are also methods using epoxy resin modified with glass fiber, which are directly applied to wind turbine blade materials to improve strength and corrosion resistance.
The application of epoxy resin in wind turbine blade materials also requires the use of chemical products such as curing agents and accelerators:
一. the most widely used epoxy resin curing agent in the wind power industry: polyetheramine.
A typical product is polyetheramine, which is also the most widely used epoxy resin curing agent in the wind power industry. Polyetheramine epoxy resin curing agents are used in the curing of base epoxy resins and structural adhesives. They possess excellent comprehensive properties such as low viscosity, long pot life, and anti-aging properties, and are widely used in wind power generation, textile printing and dyeing, railway corrosion protection, bridge and ship waterproofing, oil and shale gas extraction, and other fields. Downstream applications of polyetheramine in wind power account for over 62%. It is important to note that polyetheramine belongs to the organic amine epoxy resin class.
According to research, polyetheramine can be obtained by amination of polyethylene glycol, polypropylene glycol, or ethylene glycol/propylene glycol copolymers under high temperature and pressure. Different polyoxyalkylene structures can be selected to adjust a series of properties of polyetheramine, including reactivity, toughness, viscosity, and hydrophilicity. Polyetheramine has advantages such as good stability, resistance to whitening, good gloss after curing, and high hardness, and it is soluble in solvents such as water, ethanol, hydrocarbons, esters, ethylene glycol ethers, and ketones.
According to surveys, the Chinese polyetheramine market has a consumption scale exceeding 100,000 tons, growing at a rate of over 25% in the past few years. It is projected that by 2025, the Chinese polyetheramine market will soon surpass 150,000 tons, with a future consumption growth rate expected to be around 8%.
The main Chinese polyetheramine producer is Chenhua Co., Ltd., which has two production bases in Yangzhou and Huai’an, with a combined annual production capacity of 31,000 tons of polyetheramine (terminated amino polyether) (of which a 3,000-ton/year polyetheramine project is under construction), 35,000 tons/year of alkyl glycosides, 34,800 tons/year of flame retardants, 8,500 tons/year of silicone rubber, 45,400 tons/year of polyether, 4,600 tons/year of silicone oil, and 100 tons/year of other products. Changhua Co., Ltd. plans to invest approximately 600 million yuan in the Huai’an Industrial Park in Jiangsu Province to construct a project with an annual production capacity of 40,000 tons of polyetheramine and 42,000 tons of polyether.
In addition, representative Chinese polyetheramine (PEA) companies include Wuxi Akoli, Yantai Minsheng, Shandong Zhengda, Huangma Technology, and Wanhua Chemical. According to statistics on planned and under-construction projects, the long-term planned capacity of PEA in China will exceed 200,000 tons, and the long-term production capacity is expected to surpass 300,000 tons per year, maintaining a high growth trend in the long term.
二. The fastest-growing epoxy resin curing agent in the wind power industry: Methyltetrahydrophthalic anhydride
According to surveys, methyltetrahydrophthalic anhydride (MTHPA) is the fastest-growing epoxy resin curing agent in the wind power industry. Within the wind power epoxy curing agent field, MTHPA is also commonly used as a curing agent in high-performance epoxy resin-based carbon fiber (or glass fiber) reinforced composite materials for wind turbine blades, produced through pultrusion molding. MTHPA also has applications in electronic information materials, pharmaceuticals, pesticides, resins, and the defense industry. As a significant representative of anhydride curing agents, MTHPA is also expected to be the fastest-growing curing agent category in the future.
According to Pingtouge’s investigation, methyltetrahydrophthalic anhydride is produced by diene synthesis and subsequent isomerization of maleic anhydride and methylbutadiene. The leading domestic manufacturer is Puyang Huicheng Electronic Materials Co., Ltd., with a consumption scale of approximately several thousand tons in China. With rapid economic growth and consumption upgrading, the demand for coatings, plastics, and rubber is continuously increasing, further driving the growth of the methyltetrahydrophthalic anhydride market.
In addition, anhydride curing agents also include tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA), methylhexahydrophthalic anhydride (MHHPA), and methyl-p-nitroaniline (MNA), etc. These products can all be used in the field of epoxy resin curing agents for wind turbine blades.
三. High-performance epoxy resin curing agents in the wind power industry: Isophorone diamine and methylcyclohexanediamine.
Among epoxy resin curing agents, the highest performance varieties include isoflurane diamine, methylcyclohexanediamine, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methyl-p-nitroaniline. These curing agents possess excellent mechanical strength, suitable operating time, low exothermic curing process, and excellent workability in the pouring process, making them suitable for use in epoxy resin and glass fiber composite materials for wind turbine blades. Anhydride curing agents, which require heat curing, are more suitable for the pultrusion molding process of wind turbine blades.
Global producers of isophorone diamine include BASF AG (Germany), Evonik Industries AG (Germany), DuPont (USA), BP (UK), and Sumitomo (Japan), with Evonik being the world’s largest producer. Major Chinese producers include Evonik Shanghai, Wanhua Chemical, and Tongling Hengxing Chemical, with a consumption scale of approximately 100,000 tons in China.
Methylcyclohexanediamine is typically a mixture of 1-methyl-2,4-cyclohexanediamine and 1-methyl-2,6-cyclohexanediamine. It is an aliphatic cycloalkyl compound obtained by hydrogenation of 2,4-diaminotoluene. Methylcyclohexanediamine can be used alone as an epoxy resin curing agent, or it can be mixed with other common epoxy curing agents (such as aliphatic amines, cycloaliphatic amines, aromatic amines, acid anhydrides, etc.) or general accelerators (such as tertiary amines, imidazoles). Leading methylcyclohexanediamine producers in China include Henan Leibairui New Material Technology Co., Ltd. and Jiangsu Weiketerui Chemical Co., Ltd., with domestic consumption around 7,000 tons.
It should be noted that organic amine curing agents are not as environmentally friendly or have a longer service life as acid anhydride curing agents, but they are superior to acid anhydride curing agents in terms of performance and operating time.
Finally, while China offers a wide variety of epoxy resin curing agents for the wind power industry, their main applications are limited. The international market is actively exploring and developing new epoxy resin curing agents, leading to continuous upgrades and iterations. China’s progress in this area is slow, primarily due to the high cost of changing epoxy resin curing agent formulations in the wind power industry and the lack of relatively complete products. However, with continuous technological advancements and alignment with international standards, China’s epoxy resin curing agent products for the wind power sector will undergo continuous upgrades and iterations.
