November 22, 2021

Domestic Rise of Functional Silanes

Functional silanes are one of the four major classes of silicone materials and are widely used for their excellent performance. It can be used as an interface bridge between inorganic and organic materials or directly participate in the cross-linking reaction of organic polymeric materials, thus significantly improving the material properties. Due to its excellent performance, functional silane can be widely used in composite materials, rubber processing, plastics, adhesives, coatings and surface treatment.

China's functional silane industry chain is well laid out, and global production capacity has been gradually transferred to China. Foreign functional silane producers are constrained by cost pressure and industrial support, and the possibility of large-scale expansion of production capacity is low. The main growth driver of global functional silanes comes from China, which has become the world's largest producer. With the dual promotion of China's policy and demand, the concentration of China's functional silane industry has further increased. It is expected that Chinese silane products will continue to dominate the industry and further increase the international market share in the future market.

Functional silanes are widely used, and the continuous growth of downstream areas drives the industry development. Functional silanes mainly benefit from the pull of green tires, real estate completion cycle and composite materials.

The functional silane boom is improving, and Chinese companies are moving from quantity to quality. Along with the rise of demand in emerging fields and drawing on the development of overseas silicone companies, Chinese functional silane companies will move from quantitative to qualitative improvement in the future.

1. Functional silane industry chain overview

Functional silanes, silicone rubber, silicone oil and silicone resin are the four main categories of silicone materials. From the functional point of view, functional silanes are mostly heterogeneous and can be used as a bridge between inorganic and organic materials or directly participate in the cross-linking reaction of organic polymeric materials, which can greatly improve the material properties and are very important and widely used additives.

1.1. Functional silane industry chain

At present, there are two main production processes for functional silanes: indirect process and direct process.

The main production method of silane coupling agent is the indirect method. The indirect method takes trichlorosilane as the main raw material and reacts with methanol, ethanol, chloropropene, acetylene and other raw materials separately to produce intermediates, such as trialkoxysilane, chloropropyltrioxysilane, vinyltrioxysilane and propyltrioxysilane. The intermediates are then reacted with sodium methacrylate, allyl glycidyl ether, polysulfide, liquid nitrogen, methanol, ethanol, and butanone oxime, respectively, to obtain various functional silanes, such as epoxy silane, acryloyloxy silane, sulfur-containing silane, amino silane, and functional silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltributyloxime.

The advantage of the indirect method is that the yield is larger and some by-products can be recycled, such as the recycling of hydrogen chloride. However, the indirect method has a long production process, large investment in raw materials and equipment, as well as chlorine pollution and corrosion problems.

The main production method of silane crosslinker is the direct method. The direct method uses silicon powder, methanol or ethanol as raw materials to synthesize trialkoxysilane (trimethoxysilane, triethoxysilane, etc.), and then further reacts to produce functional silanes such as epoxy silane, acryloyloxy silane and tetraethoxysilane.

The advantages of the direct method are shortened synthesis steps, reduced chlorine contamination, lower impurity content of the product, and high resource efficiency. However, the disadvantage of the direct method is that it can only produce a small amount of silane and the product quantity is limited.

1.2. Global Silane Development

Since the 21st century, the synthetic route of silane coupling agent has developed rapidly and matured, and China has gradually stepped into the advanced ranks, and its production, consumption and export have jumped to the first place in the world. In this stage, the competition of old and standard grade products in the market has become more intense. New product development provided more convenience to users. New silane products and newly developed polymers can produce better interactions.

1.3. Functional silanes usage classification and applications

From the functional point of view, functional silanes are mostly heterogeneous structures that can serve as an interface bridge between inorganic and organic materials or directly participate in the cross-linking reaction of organic polymeric materials, thus significantly improving material properties, and are a very important and versatile class of additives. According to the use of silane coupling agent and silane cross-linking agent can be divided into two categories.

Silane coupling agent is a class of molecules containing two different chemical properties of silicone compounds, to improve the actual bonding strength of polymers and inorganic substances. Silane coupling agent is widely used in adhesives, coatings and inks, rubber, casting, glass fiber, cable, textiles, plastics, fillers, surface treatment and other industries. Common silane coupling agents include sulfur-containing silanes, amino silanes, vinyl silanes, epoxy-based silanes, methacryloyloxy silanes, etc.

Silane cross-linking agent refers to the silane containing two or more silicon functional groups, can play a bridging role between linear molecules, so that multiple linear molecules or lightly branched macromolecules, macromolecules bonded to each other cross-linked into a three-dimensional network structure, to promote or mediate the formation of covalent bonds or ionic bonds between polymer molecular chains. Cross-linking agent is the core part of one-component room temperature vulcanization silicone rubber, and is the basis for determining the cross-linking mechanism and classification of the product. According to the different condensation reaction products, the one-component room temperature vulcanized silicone rubber can be divided into different types, such as deacidified, deketoxime, dehydrated alcohols, deamines, deamides, and deacetonates.

2. Silane industry chain shifts from overseas to China

2.1.  High maturity of trichlorosilane technology

Silicon powder is the main cost of trichlorosilane, and trichlorosilane is the main raw material for the preparation of functional silane. Generally, silicon powder and hydrogen chloride are used as raw materials to prepare trichlorosilane, and then functional silanes containing silicon are prepared by trichlorosilane. In terms of total cost, raw materials occupy the main cost of trichlorosilane. In terms of cost share, silica powder is the main cost of TCS.

The main raw material silicon metal production capacity is concentrated in China, and the raw material support forms the cost advantage. In terms of cost, the average full cost of silicon metal in China is $10,400/ton, while the cost of silicon metal overseas is about $1,750/ton, which is more than $1,000/ton higher than China. In terms of production, China produced 2.1 million tons of silicon metal in 2020, accounting for about 69.3% of global production. Silicon metal production is concentrated in China, and China has the advantage of low-cost silicon metal. The development of silane in China forms a favorable support, and the functional silane industry chain is accelerating its transfer to China.

Along with China's technological breakthroughs, functional silanes are gradually stabilizing from high profits, while foreign manufacturers are constrained by costs and industry chain coordination. The capacity expansion of foreign manufacturers tends to stagnate due to the cost and industry chain support factors. Chinese companies are benefiting from the industry chain support and raw material cost, and the production capacity is gradually expanding.

2.2. Policies conducive to the development of silicone industry in China

Organic silicon materials are new high-performance materials, which are very important to promote related industrial upgrading and high-tech development. Organic silicon materials are not only an important part of the national strategic emerging industries, but also an indispensable supporting material for other strategic emerging industries. Silicone materials have always been the key new materials encouraged by the state. The promotion of policy has accelerated the development of China's organic silicon industry, gradually from import dependence to the gradual improvement of the organic silicon industry chain.

2.3. High consumption potential in developing countries mainly in China

Emerging countries and developing countries have a greater potential for growth in demand for silicones. Along with economic development, emerging countries, developing countries, consumption upgrade will be inevitable. The emerging countries, represented by China, will be the first to break through to mature silicon materials with the rapid development of economic dividends, and the development of functional silanes will be similarly accelerated.

Emerging countries and developing countries have a large population base.In the future, with the development of the economy, silicone consumption demand will reflect the huge growth potential. The Asian market represented by China and India will become the main demand growth area for silicones in the future.

2.4. China leads the growth of production capacity and has become the largest producer

Global functional silanes have been developing rapidly in the past 20 years, with a compound annual growth rate of nearly 10%. China's functional silane capacity is expanding rapidly, and with the elimination of backward capacity and the improvement of industry concentration, capacity utilization will be further improved. Global functional silane production capacity is expected to be 762,000 tons in 2023, with an average annual growth rate of about 5.0% from 2019 to 2023. Production is expected to reach about 538,000 tons in 2023, with an average annual growth rate of about 5.3% from 2018 to 2023.

3. Functional silanes are widely used and the downstream sector continues to grow

There are many varieties of functional silanes, and their applications are mainly determined by the functional group species and structure. The main application areas include composites, rubber processing, plastics, adhesives, coatings and surface treatment. In terms of global consumption of functional silanes, rubber processing accounts for 32.4%, composite materials for 18.5%, adhesives for 16.7%, plastic processing for 14.8%, and coatings and surface treatment for 11.1%.China's consumption share is in line with the global trend. The main consumption areas of rubber processing accounted for 33.9%, sealants and adhesives accounted for 17.5%, coatings, metal surface treatment and building waterproofing accounted for 17.0%, and composite materials accounted for 12.3%. The development of functional silane industry is related to macro economy and closely related to the development status of downstream industries such as construction materials, electronics, automobile, textile and glass fiber.

Article written by ellie@shsunchem.com
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