Silicone, also known as Silicone Rubber, is a versatile material made by refining silica from silicon sand. It’s a high-performance material that doesn’t dissolve in water or other solvents, is non-toxic, odorless, and highly stable, only reacting with strong alkalis or hydrofluoric acid.
Silicone stands out because of its unique features, such as excellent heat resistance, high adsorption capacity, chemical stability, and durability. It’s also waterproof and insulating, perfect for industrial applications like sealing and pressing. With a heat tolerance ranging from -40°C to 230°C and a non-toxic nature, silicone is widely used in the food industry and biomedical fields.
At Da Feng, we specialize in producing high-quality, custom silicone products. Our silicone materials meet strict food-grade standards and are certified by Taiwan SGS, ensuring safety and reliability. Whether you need silicone for food-related applications or industrial use, we provide tailored solutions to meet your needs.
Composition of Silicone Raw Materials
Silicone raw materials belong to organic silicon compounds, primarily composed of amorphous silica, commonly known as silicone. The development of silicone can be traced back to a joint venture between Dow Chemical and Corning Glass in 1943, forming the Dow Corning Company. Since then, its exceptional properties, such as excellent insulation, waterproofing, temperature resistance, anti-aging, UV radiation resistance, and non-toxicity, have led to widespread use in various industries.
Products made from silicone raw materials exhibit outstanding heat resistance and chemical stability, making them widely applicable in many fields. Silicone is not only used as a specialized material in aviation, technology, and military industry but also plays a significant role in consumer goods and daily life. Its applications have expanded to sectors such as construction, electronics, automotive, machinery, textiles, leather and paper manufacturing, chemicals, medical and healthcare, and food processing.
There are also food-grade silicone. It is safe for direct contact with food. Its characteristics being non-toxic, environmentally friendly, and non-polluting. These materials must meet high safety standards, with raw materials certified by organizations such as SGS and CTI, and comply with international standards like FDA and LFGB. This ensures food-grade silicone is a reliable and trusted material.
Common food-grade silicone products include silicone gifts, silicone daily essentials, silicone kitchenware, cake molds, chocolate molds, water dispenser pipes, coffee machine tubes, baby bottle straws, food-grade silicone bowls, silicone spoons, silicone straws, and more. These products meet the highest safety and quality standards, making silicone an indispensable material across various industries.
Two Types of Silicone Raw Materials: Organic Silicon and Inorganic Silicon
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- Organic Silicon: A type of organic silicon compound, which is created by combining silicon from quartz sand with organic macromolecules. This results in a “composite” new material known as “organic silicon.” Organic silicon exhibits characteristics of inorganic materials as well as the advantages of organic substances, allowing it to perform tasks that are difficult for other materials to handle. Organic silicon features excellent properties such as high and low-temperature resistance, weathering resistance, electrical insulation, ozone resistance, water repellency, flame retardancy, non-toxicity, non-corrosiveness, and physiological inertness. Some varieties also have oil resistance, solvent resistance, and radiation resistance. Compared to other polymers, organic silicon stands out with its superior temperature resistance, dielectric properties, weathering resistance, physiological inertness, and low surface tension.
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- Inorganic Silicon: Known as “silicon dioxide micro-powder”, this silicon is an amorphous product made from sodium silicate and sulfuric acid derived from silica. Inorganic silicon is processed and washed from naturally occurring minerals into granules or beads. Its structure resembles a sponge, with interconnected small pores forming a large surface area and system capable of adsorbing and storing moisture. Inorganic silicone is a highly active adsorption material, typically made by reacting sodium silicate with sulfuric acid, followed by aging, acid soaking, and other post-processing steps.
Organic Silicon: Usage, Types, etc.
Organic silicon is a type of organic silicon compound that contains Si-C bonds, where side chains are connected to silicon atoms through oxygen, sulfur, nitrogen, and other elements. The most common and well-studied organic silicon compounds are polysiloxanes, which are made up of Si-O-Si linkages and constitute over 90% of total usage.
Uses of Organic Silicon:
Organic silicon, with its robust properties, is used in a wide range of applications. It is not only employed in specialized materials for aerospace, innovative technologies, and military sectors but is also found in various civil industries, medical fields, and other domains. Its applications extend to industries such as construction, electronics and electrical engineering, textiles, automotive, machinery, leather, paper, chemical and light industries, metals and coatings, pharmaceuticals, and healthcare.
Products include industrial sealing rings, mobile phone cases, silicone wristbands, key pouches, silicone kitchenware, silicone mats, ice trays, cake molds, silicone nipples, baby bottles, baby bibs, teething rings, teething sticks, silicone spoons, and silicone baby food containers. Additionally, organic silicone is used in the production of realistic human organ models and medical silicone breast pads.
Types of Silicone in Organic Silicon:
Organic silicon is categorized into high-temperature vulcanizing (HTV) and room-temperature vulcanizing (RTV) types based on curing temperatures.
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- High-Temperature Vulcanizing (HTV): HTV is once again divided into two types. Solid-state silicone (HTV) and liquid silicone (LSR). Solid-state silicone, also known as heat-vulcanized silicone, is molded using processes like compression molding, extrusion, or calendering. It performs well in terms of heat and aging resistance. Liquid silicone (LSR), in a liquid state, has high fluidity, making it suitable for injection molding. LSR also features high transparency, making it ideal for medical devices and baby products that require high levels of cleanliness.
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- Room-Temperature Vulcanizing (RTV): This is further divided into single-component RTV1 and two-component RTV2. Two-component RTV2, also known as AB glue, is available in both condensation-curing RTV (curing with humidity) and addition-curing liquid silicone (cured at room temperature or with heat).
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- Solid-state silicone (HTV) Solid-state silicone (HTV) is one of the most important organic silicon products. Methyl vinyl silicone (VMQ) is the primary type in HTV, commonly known as high-temperature silicone. It is colorless, odorless, non-toxic, and free of mechanical impurities. Raw silicone is mixed with appropriate reinforcing agents, structure-control agents, vulcanizing agents, and other additives before being heated and molded or extruded. The silicone’s hardness after molding typically ranges from 30A to 70A (Shore A). It has excellent electrical insulation, high arc resistance, corona resistance, spark resistance, water resistance, moisture resistance, shock resistance, and biological inertness.Solid-state silicone is mainly used in industries such as aerospace, instrumentation, electronics, maritime, metallurgy, machinery, automotive, and healthcare. It can be used to create various shapes of sealing rings, silicone gaskets, silicone tubes, cables, as well as human organ models, blood vessels, breathable membranes, rubber molds, and precision casting demolding agents. Food-grade silicone materials, which must meet strict safety standards, are colorless, odorless, non-toxic, and comply with FDA, LFGB, and other testing standards, making them reliable. Common food-grade silicone products include silicone gifts, daily products, kitchen items, water dispensers, coffee machine tubes, baby bottle straws, food-grade silicone egg molds, chocolate molds, bowls, spoons, and straws.
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- Liquid Silicone (LSR) Liquid silicone, or injection-molded liquid silicone (LSR), is characterized by high fluidity, allowing for injection molding. The process is simple, with high precision, high production efficiency, and several other advantages, such as reduced human labor, energy, and material consumption. LSR is used in the production of all types of high-temperature silicone products and is expected to be a major development trend for silicone materials. Liquid silicone is highly transparent and does not require the addition of curing agents during molding. The hardness of LSR typically ranges from 10A to 70A (Shore A). Liquid silicone has excellent low and high-temperature stability, inertness (odorless and tasteless), transparency, ease of coloring, a wide hardness range, chemical resistance, weather resistance, strong sealing performance, and resistance to compression deformation.Common applications of liquid silicone include medical devices such as drainage tubes, catheters, dialysis tubes, medical silicone custom suction balls, medical silicone negative-pressure drainage bulbs, medical-grade silicone tubes, and breathing tubes. Liquid food-grade silicone products include baby bottle nipples, silicone straws, etc. Additionally, there are low-pressure, low-viscosity liquid silicone, conductive liquid silicone, silicone rollers, low-hardness liquid silicone, high-transparency low-viscosity liquid silicone, high-thermal-conductivity silicone potting compounds, high-rebound shock-absorbing liquid silicone, and high-tensile liquid silicone.
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- Room-Temperature Vulcanizing Silicone (RTV) Room-temperature vulcanizing silicone (RTV) was introduced in the 1960s as a new type of organic silicone elastomer. Its most notable feature is that it cures at room temperature without needing heating, making it extremely convenient to use. RTV silicone is typically composed of base polymers, crosslinking agents, catalysts, fillers, and additives. It is packaged in sealed tubes and cures by absorbing moisture from the air, making it self-curing when exposed to air. RTV silicone is widely used as adhesives, sealants, protective coatings, potting materials, and molding materials across various industries.
Types of Room Temperature Vulcanizing (RTV) Silicone:
Room temperature vulcanizing (RTV) silicone rubber can be categorized into two types based on packaging: single-component RTV silicone and two-component RTV silicone. The single-component RTV silicone, also known as RTV-1, contains only one component per unit of RTV silicone. The two-component RTV silicone, also called RTV-2 or AB glue, contains two components (A and B) per unit of RTV silicone. Two-component RTV silicone can further be divided into condensation-type RTV silicone (curing by moisture at room temperature) and addition-type RTV liquid silicone (curing at room temperature or with heat).
Advantages of RTV Silicone types:
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- Single-component RTV Silicone is convenient to use but is more challenging to cure deeply.
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- Two-component RTV Silicone offers advantages such as no exothermic reaction during curing, low shrinkage, no expansion, no internal stress, and the ability to cure both internally and on the surface. Addition-type RTV silicone’s curing time is mainly determined by temperature, so curing speed can be controlled by adjusting the temperature.
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- Single-Component RTV Silicone (RTV-1) Single-component RTV silicone cures through moisture in the air, turning into an elastic material. Depending on the curing agent, RTV-1 silicone can be formulated in various types, such as acid-extruding, oxime-extruding, alcohol-extruding, amine-extruding, and more. The curing time for RTV-1 silicone depends on several factors such as the curing system, temperature, humidity, and the thickness of the silicone layer. Increasing the temperature and humidity accelerates the curing process. Typically, after 15–30 minutes, the surface becomes non-tacky, and a 0.3 cm thick layer can cure in about a day. Full curing and strength development may take up to three weeks.RTV-1 silicone features excellent electrical properties, chemical inertness, heat resistance, natural aging resistance, flame resistance, moisture resistance, and breathability. It remains elastic between temperatures of -60°C to 200°C. RTV-1 silicone is used in adhesives, sealants, gaskets, protective coatings, and potting materials, and exhibits good bonding properties to metals, glass, ceramics, and concrete. For difficult bonding, a primer may be applied to improve adhesion. Although RTV-1 is convenient to use, it has thickness limitations (up to 6 mm) since curing is limited to the surface and proceeds slowly in thicker layers.
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- Two-Component Condensation-Type RTV Silicone (RTV-2 Condensation Silicone)Two-component RTV silicone cures via a catalyst instead of moisture. The silicone and catalyst are packaged as separate components and mix to initiate curing. RTV-2 silicone is usually packaged with components A (silicone) and B (catalyst), which must be mixed in a specific ratio before curing begins. RTV-2 silicone is liquid, which makes it flow well and cures faster compared to RTV-1. It is used in industries such as electronics, automotive, machinery, construction, textiles, chemicals, and printing for insulation, packaging, sealing, moisture-proofing, shock resistance, and manufacturing roller materials. RTV-2 silicone is also commonly used in mold-making due to its excellent release properties and high-fidelity reproduction for casting products like resins, wax, cement, and more.
Types of Two-Component RTV Silicone:
- Two-Component Condensation-Type RTV Silicone (RTV-2 Condensation Silicone)Two-component RTV silicone cures via a catalyst instead of moisture. The silicone and catalyst are packaged as separate components and mix to initiate curing. RTV-2 silicone is usually packaged with components A (silicone) and B (catalyst), which must be mixed in a specific ratio before curing begins. RTV-2 silicone is liquid, which makes it flow well and cures faster compared to RTV-1. It is used in industries such as electronics, automotive, machinery, construction, textiles, chemicals, and printing for insulation, packaging, sealing, moisture-proofing, shock resistance, and manufacturing roller materials. RTV-2 silicone is also commonly used in mold-making due to its excellent release properties and high-fidelity reproduction for casting products like resins, wax, cement, and more.
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- Condensation-Type RTV Silicone (Moisture Curing at Room Temperature) The curing time for RTV-2 condensation silicone depends on the type and amount of catalyst used and the temperature. The more catalyst used, the faster the curing, and the shorter the pot life. Under typical conditions, the gel material has a pot life of several hours at room temperature. Curing to complete solidification typically takes around a day, though curing speed can be increased by using accelerators. RTV-2 silicone can maintain flexibility within a temperature range of 65°C to 250°C and exhibits excellent electrical performance and chemical stability. It is widely used in electronics and electrical components for sealing, moisture protection, and vibration resistance, enhancing the performance and stability of these products. RTV-2 silicone is especially suitable for deep potting applications, where faster curing times provide advantages over RTV-1. After curing, RTV-2 silicone also exhibits excellent anti-stick properties, minimal shrinkage during curing, and is ideal for mold-making, particularly for casting materials such as epoxy, polyester resins, polyurethane, and low-melting alloys.
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- Addition-Type RTV Silicone (Curing at Room Temperature or with Heat) Addition-type RTV silicone has two main types: low-strength silicone gel and high-strength silicone. The curing process involves a reaction between the vinyl groups on the silicone polymer chains and the silane hydride groups in the crosslinking agents. Unlike condensation silicone, addition-type RTV silicone does not release byproducts during curing, meaning no shrinkage occurs during the process. This type of silicone is non-toxic, offers high mechanical strength, and demonstrates excellent resistance to hydrolysis (even under high-pressure steam), low compression set, low flammability, deep curing, and controllable curing speed via temperature. It can also meet food-grade standards, making it ideal for food molds, such as cake or chocolate molds.
Types of Silicone Raw Materials – Inorganic Silicon
Inorganic silica gel is divided into microporous silica gel, type B silica gel, and macroporous silica gel. Its main component is silicon dioxide, which is an amorphous product obtained through a series of post-treatment processes such as aging and acid bubbling, following a reaction between sodium silicate and sulfuric acid in silicon sand. It is usually a transparent or milky-white granular solid and is a highly active adsorbent material.
It is formed by the reaction of sodium silicate and sulfuric acid, with the chemical formula mSiO2.nH2O. It is an amorphous substance, processed into granular or bead-like forms, insoluble in water or any solvents, non-toxic, odorless, and chemically stable. It does not react with any substances except strong bases and hydrofluoric acid. Inorganic silica gel has different microporous structures due to different manufacturing methods. Its chemical composition and physical structure determine its many characteristics that are difficult for other similar materials to replace, such as high adsorption performance, good thermal stability, chemical stability, and high mechanical strength.
Inorganic silicates can be divided into soluble silicates, including sodium silicate, potassium silicate, potassium sodium silicate, silica gel, and soluble silicates; insoluble silicates, including calcium silicate, aluminum silicate, magnesium silicate, lead silicate, aluminosilicate, and other materials. Amorphous silicon dioxide includes silica sol, silica gel, fumed silica, and precipitated silica. Zeolite molecular sieves are classified into low-silicon, medium-silicon, and high-silicon types. Silicon elements and their non-metallic oxides include single-crystal silicon, polycrystalline silicon, silicon carbide, silicon nitride, and halogenated silicon compounds.
Characteristics of Inorganic Silicon
The structure of inorganic silica gel is very similar to a sponge, consisting of interconnected small pores that form a capillary adsorption system with a large surface area, capable of adsorbing and retaining moisture. Under 100% humidity conditions, it can absorb and condense moisture equivalent to 40% of its own weight. It has high adsorption performance and can adsorb various substances. When dilute sulfuric acid (or hydrochloric acid) is added to a water solution of water glass and left to stand, it forms a hydrated silica gel that solidifies, with good thermal stability, stable chemical properties, and high mechanical strength.
Usage of Inorganic Silica Gel:
Inorganic silicates are an important product series in the inorganic salt industry, characterized by a wide variety and extensive applications, ranging from general civilian use to cutting-edge technologies, including adhesives, detergents, rubber, paper making, plastics, coatings, ceramics, environmental protection, metallurgy, casting, heat-insulating materials, catalysts, soil stabilizers, electronics, solar cells, optical fibers, and more.
Inorganic silicon is used as a desiccant, humidity regulator, deodorant, and more; in industry, as a hydrocarbon decolorizer, catalyst carrier, pressure-swing adsorbent, etc.; in fine chemicals, as a separation and purification agent, beer stabilizer, paint thickener, toothpaste abrasive, deglossing agent, and more. Inorganic silica has a wide range of packaging material applications, suitable for drying, moisture prevention, rust prevention, and can also be used as a chemical carrier and dehydration refining agent, mainly used for room humidity regulation, catalysts, and carriers.
Advantages of Silicone Raw Materials
What are advantages of silicone raw materials?
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- Wide Temperature Range Silicone materials are resistant to temperatures ranging from -40°C to 230°C, with heat resistance up to 260°C. They can be safely used in cooking and possess excellent elasticity and extensibility. Whether in the oven or refrigerator, their functionality remains intact, making them a new choice for many baking tools. There’s no need to worry about expansion and cracking due to large temperature differences, making silicone ideal for cooking and environments with extreme temperature conditions.
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- Safe and Non-Toxic Silicone is made from natural minerals (silicon dioxide) and is close to human skin. It is non-toxic, free of heavy metals, and safe for use in microwaves, dishwashers, and baby products such as nipples. There’s no concern about releasing toxins when damaged. Therefore, it is suitable for medical products in contact with skin as well as kitchenware. Food-grade silicone certified by the FDA is commonly used for nipples, silicone tableware, etc.
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- Medical Grade / Biocompatibility Medical-grade Silicone is a special silicone material that is widely used in medical devices and healthcare products. It typically has good toughness and resilience, capable of withstanding high and low temperatures. It also possesses excellent antibacterial properties and wear resistance. When it enters the human body, silicone maintains excellent compatibility with minimal tissue reactions, providing long-term reliable performance.
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- Excellent Waterproofing Silicone waterproof sealing materials usually exhibit good sealing properties. They can effectively prevent moisture and other liquids from penetrating the surface of an object, thereby protecting it from water damage and moisture. Different brands and models of silicone waterproof sealing materials may have varying sealing performances. Common silicone products include sealing rings and O-rings.
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- Durability and Long Lifespan Silicone is a durable material capable of withstanding temperature stress and exhibiting good wear resistance. Different brands and models of silicone may have different lifespans, but most silicone products can provide a service life of at least 10 years.
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- Excellent Weather Resistance Ordinary rubber rapidly degrades under the action of ozone generated by corona discharge, while silicone is unaffected by ozone. Furthermore, when exposed to ultraviolet light and other climatic conditions for extended periods, its physical properties change only slightly. It is used for outdoor sealing materials
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- Good Electrical Properties Silicone is an insulating material with excellent electrical resistance. This means it effectively prevents the flow of electricity through the surface of an object, protecting electronic devices from electrical damage. Silicone also has excellent resistance to high-voltage corona discharge and arc discharge, making it suitable for high-voltage insulators, TV high-voltage caps, and electrical components.
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- Conductivity Silicone is an insulating material, but when conductive fillers (such as carbon black) are added, silicone becomes conductive. It is used in components such as keyboard contacts, electric heating elements, anti-static parts, high-voltage cable shielding, and medical conductive gel sheets. When certain thermal fillers are added, silicone can also possess thermal conductivity, such as in heat sinks, thermal sealing gaskets, and heat transfer rollers in copiers and fax machines.
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- Fire Resistance/Flameproofing Silicone is a non-flammable material and cannot be burned, providing protection from fire damage. When a small amount of flame retardant is added, silicone becomes flame retardant and self-extinguishing. Additionally, because silicone does not contain organic halides, it does not emit smoke or toxic gases when burned. It is suitable for use in fire-sensitive applications.
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- Variety of Colors Silicone can be customized in a variety of colors according to customer needs, including red, green, blue, purple, yellow, and transparent. These colors can be achieved by adding pigments, meaning different brands and models of silicone may offer various color options.
Silicone Raw Material Manufacturers
Dafeng Zhengye focuses on the customized development of silicone and has passed international ISO9001 certification for its production processes. Dafeng Zhengye’s silicone raw materials meet FDA and LFGB food-grade standards and have been tested by SGS Taiwan.
The company has numerous well-known representative clients in industries such as manufacturing, electronics, food processing, and medical devices. As a professional silicone factory and Taiwanese silicone manufacturer, Dafeng Zhengye can provide the most suitable product development services for you.
