Market Size Forecast for Thermal Insulation Material Rigid Felt

 

Compared with soft graphite felt, hard graphite felt has higher volume density and strength, and has a wider range of applications. It can be used not only in single crystal furnaces and polycrystalline furnaces in the photovoltaic and semiconductor industries, but also in powder metallurgy industrial furnaces and vacuum sintering furnaces. The author introduced soft graphite felt and market size forecast in the first issue, and this issue will introduce hard graphite felt and its market and size.

 

Introduction to Graphite Felt

Graphite Felt (Carbon Fiber-Reinforced), also known as reinforced composite felt or cured felt (also commonly known as carbon fiber composite felt), is a thermal insulation material.

It can be seen as consisting of a main body (carbon fiber) and auxiliary materials (such as thermosetting resin, carbon paper, graphite paper, etc.). The general manufacturing process is to combine graphite paper, polyacrylonitrile-based carbon felt, and polyacrylonitrile-based carbon cloth into one, and then cure and form them, and then perform one or two high-temperature treatments to obtain the result.

Short carbon fiber scraps can also be used to produce carbon fiber felt through recycling. At the same time, according to the different types of raw materials for carbon fiber, felt can be divided into asphalt-based felt, polyacrylonitrile-based felt, viscose-based felt, etc.

 

 

Compared with Soft Graphite Felt, Hard Graphite Felt has the Following Advantages:

1. Easy to operate, can be placed directly without wrapping;
2. Long service life, hardening treatment is conducive to improving ablation resistance and air flow erosion resistance;
3. Good thermal insulation effect, heat is not easy to penetrate, and has a certain heat reflection ability in the case of coating;
4. Less dust, which is conducive to controlling the carbon content in the crystal growth process and improving crystal quality.

 

Preparation Process

The preparation methods of graphite hard felt mainly include lamination, integral needle punching and vacuum filtration.

1. Lamination is to bond thin Carbon Fiber Felt layer by layer with thermosetting resin. By placing the prepregs laid layer by layer between the upper and lower flat molds and curing them under pressure and high temperature, this process can directly use the production methods and equipment of wood plywood, and improve and perfect it according to the flow properties of the resin. This molding process is mainly used to produce composite materials of different specifications and uses. It has the characteristics of high mechanization and automation, stable product quality, and batch utilization, but the equipment investment is large and the cost is high.

 

Figure: Production Process of Cured Felt

 

2. Needle punching integral structure refers to a method of preparing a rigid carbon fiber integral felt by connecting carbon fibers into a felt body of a certain thickness through a needle punching process, directly hot pressing the insulation material through dipping, and then carbonizing, graphitizing and subsequent chemical vapor deposition processes.

 

This method not only overcomes the shortcomings of the rigid carbon fiber integral felt prepared by the traditional lamination method, such as insufficient transverse shear strength, easy dissection and cracking, and uneven overall density and performance, but also has the characteristics of simple process, low cost and short cycle compared to the three-dimensional woven structure.

 

This method technology is relatively mature abroad, especially in Japan, where a large part of the carbon-carbon composite materials for thermal insulation are prepared by integral needle punching molding. However, due to the technical blockade of my country by foreign countries, the development of integral needle punching molding in China is relatively slow, and only a few companies have this technology through their own research and development.

 

3. The vacuum filtration molding method is to mix the chopped carbon fiber with the diluted resin binder to obtain a uniformly dispersed slurry, and then inject the slurry into the vacuum filtration mold cavity. The vacuum pump allows the liquid in the slurry to flow out of the mold with the airflow so that the chopped carbon fiber is deposited in the mold to obtain a carbon fiber hard felt prefabricated embryo, and then obtain a hard carbon fiber insulation felt after curing and carbonization.

 

From its molding method, it can be seen that according to the shape of the vacuum filtration mold, not only can a hard carbon fiber integral felt be prepared, but also various shapes of carbon-carbon composite material special-shaped parts can be produced. The surface of the hard carbon fiber integral felt prepared by the vacuum filtration molding method is relatively rough, the chopped fiber arrangement is chaotic and complex, and there is a serious powdering phenomenon.

 

 

Figure: Vacuum Filtration Molding Method

 

Graphite hard felt prepared by different processes has three types of structures and different product characteristics, as shown in the following table:

 

According to the advantages and disadvantages of these three types of insulation felt structures, they can be used in different application areas.

 

Application and Market Forecast of Graphite Hard Felt

 

The preparation of materials must be guided by market demand. As an insulation material in the field of high temperature resistance, it must meet the following requirements:

1. It has high thermal insulation and low thermal conductivity;
2. It has certain strength, surface properties and purity according to the use environment
3. It has corrosion resistance in special gas atmospheres;
4. According to different application scenarios, there are different requirements for the ash content of the product.

 

1. In the field of photovoltaic single crystal silicon pulling, graphite hard felt exists as a thermal insulation material and can be used in furnace bottoms, guide tubes, cover plates, insulation tubes and other parts. It is worth noting that graphite hard felt must have a low ash content, especially in the semiconductor field, usually less than 20ppm. There are few domestic manufacturers that can meet this ash content requirement.

 

 

Figure: Different Application Areas Of Graphite Soft Felt and HardFelt (Source: MiG Prospectus)

 

In the past two years, with the cyclical rise of China’s photovoltaic and semiconductor markets, the market demand for graphite soft felt and graphite hard felt has continued to rise. According to the data of existing and expansion projects of major photovoltaic companies, it is estimated that the demand for graphite hard felt in 2024 and 2025 will be 3,300 tons and 3,500 tons respectively.

 

Figure: Calculation of curing felt space in the domestic photovoltaic market, data source: announcements of major companies, CPIA, and Jinou New Materials Research Institute.

 

Based on this year’s market conditions and the increasingly mature industrial technology, assuming that the average gross weight selling price of curing felt materials is about 220,000 yuan/ton, the market size of curing felt in the photovoltaic field will reach 800 million yuan by 2025.

 

2. In the field of silicon carbide semiconductors, although there is no specific market space value, according to the prospectus data of Jingsheng Co., Ltd. (688478.SH), the industry’s single-unit equipment output level is about 375 pieces/year-500 pieces/year. Based on this calculation, in order to meet market demand, the number of silicon carbide single crystal furnaces will reach 9,440-12,587 units by 2026. Based on the demand for thermal insulation carbon materials for each silicon carbide single crystal furnace of 0.06 tons and a replacement cycle of 3 months, the global demand for thermal insulation carbon materials for silicon carbide single crystal furnaces in the semiconductor field in 2026 is about 2,266-3,021 tons.

 

3. In the field of powder metallurgy, there is a need for thermal insulation of the high-temperature furnace body used in the process. Because of its high strength requirements, the overall needle-punched structure of carbon fiber insulation felt is more widely used. Therefore, it can be directly made into hard felt insulation tubes, furnace covers and insulation door panels for use.

 

Figure: Cured Felt Parts

According to PMR (Persistence Market Research), despite the 2019 COVID-19 pandemic, global sales of powder metallurgy will maintain a compound growth rate of 3.4% from 2017 to 2021, and the global market size will reach US$8.9 billion in 2021.

 

At the same time, according to the “China Metal Powder Industry Development Status Analysis and Investment Prospects Research Report (2023-2030)” released by Guanyan Report Network, the market size of my country’s powder metallurgy industry is expected to maintain an annual compound growth rate of 5.0%, and may reach 18.28 billion yuan in 2023.

 

 

Figure: Powder Metallurgy Industry Market Forecast

 

Therefore, as the application fields of powder metallurgy continue to develop, its demand for high-temperature thermal insulation carbon materials will also increase accordingly.

 

Conclusion

 

Although the market demand for carbon-based thermal insulation materials is on the rise, however, industry competition is intensifying and the pressure to reduce costs and increase efficiency is increasing. Therefore, only companies that master the core technology of low-cost preparation of high-quality thermal insulation carbon materials can effectively control production costs while ensuring product quality and maintain competitive advantages.