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 the manufacturing of wind turbine blades, epoxy resin is widely used in the structural components, connectors, and coatings of blades. Epoxy resin can provide high strength, high stiffness, and fatigue resistance in the supporting structure, skeleton, and connecting parts of the blade, ensuring the stability and reliability of the blade.

Epoxy resin can also improve the wind shear and impact resistance of blades, reduce blade vibration noise, and improve wind power generation efficiency. At present, epoxy resin and glass fiber modified curing are still used directly in wind turbine blade materials, which can improve strength and corrosion resistance.

In wind turbine blade materials, the application of epoxy resin also requires the use of chemical products such as curing agents and accelerators:

Firstly, the most commonly used epoxy resin curing agent in the wind power industry is polyether amine

A typical product is polyether amine, which is also the most commonly used epoxy resin curing agent product in the wind power industry. Polyether amine epoxy resin curing agent is used in the curing of matrix epoxy resin and structural adhesive. It has excellent comprehensive properties such as low viscosity, long service life, anti-aging, etc. It has been widely used in wind power generation, textile printing and dyeing, railway anti-corrosion, bridge and ship waterproofing, oil and shale gas exploration and other fields. The downstream of polyether amine accounts for more than 62% of wind power. It should be noted that polyether amines belong to organic amine epoxy resins.

According to the investigation, polyether amines can be obtained by amination of polyethylene glycol, polypropylene glycol, or ethylene glycol/propylene glycol copolymers under high temperature and pressure. Choosing different polyoxoalkyl structures can adjust the reaction activity, toughness, viscosity, and hydrophilicity of polyether amines. Polyether amine has the advantages of good stability, less whitening, good gloss after curing, and high hardness. It can also dissolve in solvents such as water, ethanol, hydrocarbons, esters, ethylene glycol ethers, and ketones.

According to the survey, the consumption scale of China’s polyether amine market has exceeded 100000 tons, showing a growth rate of over 25% in the past few years. It is expected that by 2025, the market volume of polyether amines in China will exceed 150000 tons in the short term, and the consumption growth rate of polyether amines is expected to be around 8% in the future.

The production enterprise of polyether amine in China is Chenhua Co., Ltd., which has two production bases in Yangzhou and Huai’an. It has a total of 31000 tons/year of polyether amine (end amino polyether) (including a design capacity of 3000 tons/year of polyether amine project under construction), 35000 tons/year of alkyl glycosides, 34800 tons/year of flame retardants, 8500 tons/year of silicone rubber, 45400 tons/year of polyether, 4600 tons/year of silicone oil, and other production capacities of 100 tons/year. Future Changhua Group plans to invest approximately 600 million yuan in the Huai’an Industrial Park in Jiangsu Province to build an annual production of 40000 tons of polyether amine and 42000 tons of polyether projects.

In addition, representative enterprises of polyether amine in China include Wuxi Acoli, Yantai Minsheng, Shandong Zhengda, Real Madrid Technology, and Wanhua Chemical. According to the statistics of planned under construction projects, the long-term planned production capacity of polyether amines in China will exceed 200000 tons in the future. It is expected that the long-term production capacity of polyether amines in China will exceed 300000 tons per year, and the long-term growth trend will continue to be high.

Secondly, the fastest growing epoxy resin curing agent in the wind power industry: methyltetrahydrophthalic anhydride

According to the survey, the fastest growing epoxy resin curing agent in the wind power industry is methyltetrahydrophthalic anhydride curing agent. In the field of wind power epoxy curing agents, there is also methyl tetrahydrophthalic anhydride (MTHPA), which is the most commonly used curing agent in high-performance epoxy resin based carbon fiber (or glass fiber) reinforced composite materials for wind power blades through extrusion molding process. MTHPA is also used in electronic information materials, pharmaceuticals, pesticides, resins, and national defense industries. Methyl tetrahydrophthalic anhydride is an important representative of anhydride curing agents and also the fastest growing type of curing agent in the future.

Methyltetrahydrophthalic anhydride is synthesized from maleic anhydride and methylbutadiene through diene synthesis and then isomerized. The leading domestic enterprise is Puyang Huicheng Electronic Materials Co., Ltd., with a consumption scale of about a thousand tons in China. With rapid economic growth and consumption upgrading, the demand for coatings, plastics, and rubber is also continuously increasing, further driving the growth of the methyl tetrahydrophthalic anhydride market.

In addition, anhydride curing agents also include tetrahydrophthalic anhydride THPA, hexahydrophthalic anhydride HHPA, methylhexahydrophthalic anhydride MHHPA, methyl-p-nitroaniline MNA, etc. These products can be used in the field of wind turbine blade epoxy resin curing agents.

Thirdly, the epoxy resin curing agents with the best performance in the wind power industry include isophorone diamine and methylcyclohexane diamine

Among epoxy resin curing agent products, the most high-performance curing agent varieties include isoflurone diamine, methylcyclohexanediamine, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl-p-nitroaniline, etc. These curing agent products have excellent mechanical strength, suitable operating time, low curing heat release, and excellent injection process operability, and are applied in the composite materials of epoxy resin and glass fiber for wind turbine blades. Anhydride curing agents belong to heating curing and are more suitable for the extrusion molding process of wind turbine blades.

The global production enterprises of isophorone diamine include BASF AG in Germany, Evonik Industries, DuPont in the United States, BP in the UK, and Sumitomo in Japan. Among them, Evonik is the largest isophorone diamine production enterprise in the world. The main Chinese enterprises are Evonik Shanghai, Wanhua Chemical, Tongling Hengxing Chemical, etc., with a consumption scale of about 100000 tons in China.

Methylcyclohexanediamine is usually 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 a curing agent for epoxy resins, and can also be mixed with other common epoxy curing agents (such as fatty amines, alicyclic amines, aromatic amines, acid anhydrides, etc.) or general accelerators (such as tertiary amines, imidazole). The leading producers of methylcyclohexane diamine in China include Henan Leibairui New Material Technology Co., Ltd. and Jiangsu Weiketerri Chemical Co., Ltd. The domestic consumption scale is about 7000 tons.

It should be noted that organic amine curing agents are not as environmentally friendly and have a longer shelf life as anhydride curing agents, but they are superior in performance and operating time compared to anhydride curing agent varieties.

China has a wide variety of epoxy resin curing agent products in the wind power industry, but the main products used are single. The international market is actively exploring and developing new epoxy resin curing agent products, and the curing agent products are constantly upgrading and iterating. The progress of such products in the Chinese market is slow, mainly due to the high cost of formula replacement for epoxy resin curing agent products in the wind power industry, and the absence of relatively complete products. However, with the continuous advancement of technology and the integration of epoxy resin curing agents with the international market, China’s epoxy resin curing agent products in the wind power field will also undergo continuous upgrades and iterations.