Silicone is becoming increasingly popular for its eco-friendly, soft texture, non-toxic safety, and chemical stability. Many products are now being made from silicone. Common types of silicone include industrial-grade silicone, food-grade silicone, and medical-grade silicone. Industrial silicone products include seals, O-rings, silicone cake molds used in the food processing industry, silicone nipples and bibs in baby products, and various medical products such as catheters and chest drainage tubes. With the widespread use of silicone and its diverse manufacturing methods, it is crucial for companies developing new products to select a professional and suitable silicone factory. This article will introduce silicone, its application types, and how to choose the right silicone factory.
What is Silicone?
Silicone, in English, is derived from silicon extracted from silicon sand and refined into silicon dioxide. It is a highly active adsorbent material, insoluble in water and any solvent, non-toxic, odorless, and chemically stable, reacting only with strong alkalis and hydrofluoric acid. Silicone’s properties vary depending on the manufacturing method, including high adsorption performance, excellent thermal stability, chemical stability, and mechanical strength. Due to its waterproof and insulating qualities, silicone is widely used in industrial sealing and pressing applications, ensuring product stability. In terms of temperature resistance, silicone can withstand temperatures from -40°C to 230°C, making it especially suitable for the food industry and biomedicine due to its non-toxic nature.
Silicone products can be divided into two major categories based on their nature and composition:
Organic Silicon
Organic silicon is a type of organosilicon compound. In simple terms, chemists combine silicon from quartz sand with organic macromolecules to create a “composite” new material, known as “organic silicon.” Organic silicon has both the characteristics of inorganic substances and the advantages of organic substances, allowing it to perform tasks that other materials cannot. Organic silicon has many excellent properties such as high and low-temperature resistance, weathering resistance, electrical insulation, ozone resistance, hydrophobicity, flame retardancy, non-toxicity, corrosion resistance, and physiological inertness. Some varieties also possess oil resistance, solvent resistance, and radiation resistance. Compared to other polymer materials, the most outstanding properties of organic silicon products are excellent temperature resistance, dielectric properties, weather resistance, physiological inertness, and low surface tension.
Organic silicon can be divided into room-temperature vulcanized types and high-temperature vulcanized types based on vulcanization temperature. High-temperature vulcanization is further divided into heat-vulcanized silicone (HTV) and liquid silicone (LSR). Heat-vulcanized silicone refers to the commonly seen solid silicone, which is molded using methods like compression molding (hot pressing), extrusion, and calendering. This type of silicone performs well in cold and heat resistance and aging. Liquid silicone (LSR) is in a liquid state with high flowability, and its production method is primarily injection molding. Liquid silicone also has high transparency, making it suitable for medical devices and baby products where cleanliness is critical. Room-temperature vulcanized types are further divided into single-component RTV1 and two-component RTV2. Two-component RTV2, also known as AB glue, can be divided into condensation-type room-temperature vulcanizing silicone (vulcanized by room temperature moisture) and addition-type room-temperature vulcanizing liquid silicone (vulcanized at room temperature or heated).
Inorganic Silicon
Inorganic silicon, scientifically known as “silicon dioxide micropowder,” is an amorphous product made from sodium silicate and sulfuric acid derived from silicon soil. Inorganic silicon is processed from naturally occurring minerals into granular or bead-like forms. Its structure resembles a sponge, with interconnected small pores forming a capillary adsorption system with a massive surface area that can absorb and retain moisture. Inorganic silica gel is a highly active adsorbent material, usually produced by reacting sodium silicate with sulfuric acid, followed by aging, acid soaking, and other post-processing steps.
Inorganic silica gel is further divided into microporous silica gel, Type B silica gel, and macroporous silica gel. Its main component is silicon dioxide, and it is an amorphous product made by reacting sodium silicate with sulfuric acid, followed by aging and acid soaking. Typically, it is a transparent or milky white granular solid and is a highly active adsorbent material. It is formed through the reaction of sodium silicate and sulfuric acid, with the chemical formula mSiO2.nH2O. It is an amorphous substance, processed into granular or bead forms, insoluble in water and any solvent, non-toxic, odorless, and chemically stable. It does not react with any substances except strong alkalis and hydrofluoric acid. Inorganic silica gel has different micropore structures based on its manufacturing process. Its chemical composition and physical structure give it many unique characteristics that are hard to replace with other similar materials, such as high adsorption performance, excellent thermal stability, chemical stability, and high mechanical strength.
Silicone Factory Product Manufacturing Process
Silicone is a type of organic silicon product that has excellent properties such as high and low-temperature resistance, UV resistance, radiation resistance, weather resistance, electrical insulation, high permeability, physiological inertness, low compression permanent deformation, and fatigue resistance. Therefore, silicone is widely used in industries such as aviation, aerospace, electronics, electrical, light industry, machinery, construction, chemicals, medicine, daily necessities, and food processing. Silicone molding methods include compression molding, injection molding, extrusion, calendering, transfer molding, and drop molding.
Silicone Product Manufacturing Process:
The silicone manufacturing process includes mold creation, incoming material inspection, material selection and mixing, rubber mixing, cutting, molding (compression, liquid, extrusion, drop molding), processing/backing/gluing, secondary vulcanization, printing, spraying, laser engraving, full inspection, quality assurance, packaging, shipping, and other steps in the silicone production process.
1. Mold Creation
Design and create molds based on the 3D drawing files for the product to be made.
2. Incoming Material Inspection
Purchase the silicone raw materials according to the product characteristics and perform quality inspection upon arrival to ensure the materials meet the quality requirements.
3. Material Selection and Mixing
Select the necessary additives, such as curing agents and color masterbatches, in addition to the raw materials.
4. Rubber Mixing
Silicone raw materials are typically in block form, usually milky white. These raw materials cannot be directly molded by heat pressure and require the addition of curing agents (catalysts). If the product has special requirements such as color, glow-in-the-dark, fluorescence, phosphor, or conductivity, appropriate additives such as color masterbatches, glow powders, fluorescent powders, phosphors, or conductive particles are also added. The raw materials, curing agents, and other additives are mixed in a rubber mixing machine. The mixing time typically lasts about 30 minutes (depending on the weight of the raw materials and the gap between the rollers).
5. Cutting
After mixing, the silicone material is cut into the desired size (length, width, and thickness) and placed on a material rack for resting. The resting time is usually around 8 hours (the raw material is protected with PE film on both sides to ensure cleanliness).
6. Molding
After resting, the silicone material is molded using methods such as compression molding, liquid molding, extrusion, and drop molding.
Currently, there are two types of high-temperature silicone on the market: solid silicone and liquid silicone. Solid silicone molding is further divided into hot pressing and extrusion molding, while liquid silicone molding is divided into injection molding and drop molding.
Common Silicone Processing and Molding Technologies in Silicone Factories
1. Hot Press Molding
This technology utilizes the temperature and pressure of a hydraulic press to vulcanize and mold solid silicone products using molds. This technique is commonly used for single-color silicone custom products. It can also be applied to dual-color and dual-hardness silicone custom products or multi-color and multi-hardness, plastic or metal encapsulated products. For encapsulated items with temperature requirements, the item usually needs to withstand 180°C without deformation. After molding, the silicone can resist heat up to around 230°C.
2. Liquid Injection Molding
This is a two-component semi-transparent liquid silicone rubber material suitable for injection molding processes. Liquid silicone injection molding generally involves vulcanizing high-performance liquid silicone and combining it with precise, stable injection molding equipment to form a new processing system. Liquid silicone injection molding requires the two liquid components, A and B, to be loaded into the equipment. From mixing to molding, the process is fully automated, simplifying the process and reducing processing time while enabling high-quality customized liquid silicone products. The vulcanization temperature of liquid silicone molding typically ranges from 110°C to 150°C, so the embedded items need to withstand temperatures above 150°C without deformation.
3. Extrusion Molding
Similar to the common water pipe, extrusion molding refers to the process where the material is heated and vulcanized as it is pushed forward by a screw through the extruder barrel. The material is continuously shaped into various cross-sectional products or semi-products. The extruder head also determines the product’s cross-sectional shape, which has a fixed length. Under the combined effect of force and temperature, the product is vulcanized and formed as it exits the extruder head. Silicone custom products molded by this process are generally strip-shaped, with various cross-sectional shapes, such as rectangular bars, circular silicone tubes, etc.
For solid silicone, common hardness ranges from Shore A 30 to Shore A 70, while liquid silicone typically has a hardness ranging from Shore A 0 to Shore A 70. Liquid silicone with hardness below Shore A 0 also exists, but it is custom-made and requires Shore C hardness measurement. Liquid silicone can also be produced with hardness between 80 and 90, but it is more brittle and not commonly used. For hardness above 90, Shore D hardness measurement is used, and this type of silicone has a very high hardness but little elasticity.
Generally, when silicone hardness is below 10, the silicone has low tear strength, high elongation, and is prone to deformation. When hardness exceeds 40, tear strength decreases, and the silicone becomes brittle, easily breaking or cracking. The optimal silicone hardness for tear strength, elongation, and other properties is typically in the range of Shore A 20-40. The most commonly used silicone hardness for everyday products like silicone bowls, silicone mats, and silicone tubes is Shore A 50-70.
Silicone Applicaitons in Different Industries
1. Electronics Industry
The electronics and electrical industry was one of the earliest to use silicone as an insulation material, with a large demand. This is mainly because high-temperature vulcanized silicone is resistant to extreme temperatures, has excellent electrical properties, and maintains performance across a wide temperature range and electrical frequency range. High-temperature vulcanized silicone products ensure electrical appliances’ stable performance and safety. Products include electrical connectors, electrical sealing and vibration-damping components, high-temperature potentiometer seals, etc. Conductive high-temperature vulcanized silicone, which contains conductive fillers (such as carbon black or metal powders), can be used for conductive connectors in devices like computers, remote control systems, toys, telephones, and more. Conductive silicone is also widely used in microwave ovens, fax machines, and leadless integrated circuits. Many silicone products are used in televisions, including high-voltage caps made from silicone. Silicone insulators are replacing ceramic products and are widely used in transmission lines, especially ultra-high-voltage lines. Conductive silicone is also used in the electrical contact components of devices like computers and telephones, as well as liquid crystal display contact parts. Flame-retardant and radiation-resistant silicone used in wires and cables is widely used in nuclear power plants. Silicone heating pads and tapes are used for controlling the working temperatures of precision instruments and oil pipelines, and in the medical field for therapeutic heating blankets.
2. Automotive Industry
The application of silicone in the automotive industry is growing rapidly. Silicone materials, especially those with various characteristics, are resistant to fuel and lubricants, improving the performance of automotive components and reducing maintenance costs. Silicone can be used in automotive ignition wires, spark plug protectors, heating and radiator hoses, muffler linings, battery connectors, and fluorosilicone fuel pumps. Rubber products such as bushings, soft pads, belts, protectors, caps, and seals near the engine and transmission need to withstand temperatures of 175°C, and some areas need to withstand temperatures above 300°C. In such cases, conventional organic rubber is not suitable, and silicone is required. Silicone is also used in sealing high-temperature furnaces, low-temperature refrigeration components, heat-processing product conveyors in metal processing, and thermal radiation devices.
3. Food Processing Industry
Food-grade silicone is made using newly imported food-grade silicone raw materials and scientific production processes, making the product highly adaptable. It has advantages such as high transparency, odorless, non-yellowing, and no frosting. Food-grade silicone is an addition-curing silicone, offering high transparency and stability. It can withstand temperatures up to 230°C without degradation in sealed environments. Food-grade silicone is processed with scientific formulas and advanced techniques. The product is soft, stable at high temperatures, and has excellent performance. In today’s health-conscious world, food-grade silicone is gradually replacing food-grade plastics. Food-grade silicone products are mainly used in products that come in contact with the human esophagus, such as silicone tubes, mats, plates, and fabric-covered silicone hoses for the food processing industry. These products are phthalate-free, widely used in coffee pots, water heaters, bread machines, sterilization cabinets, drinking machines, boiling kettles, electric rice cookers, frying pans, juicers, and other machinery. They are also used for food molding, chocolate molds, candy molds, cake molds, silicone ice cube trays, etc.
4. Maternal and Baby Products
Silicone is an environmentally friendly material, and maternal and baby products are made from food-grade certified silicone raw materials. Food-grade silicone has excellent properties, high stability, and can withstand temperatures from 40-230°C. It is easy to clean and has a certain degree of elasticity and toughness, so it is not prone to deformation, aging, or breakage. It is highly adaptable and can be used in various conditions, such as in the presence of oil, freezing temperatures, or high heat. Many maternal and baby products are made from silicone, with the most common items being silicone nipples, silicone baby bottles, baby bibs, teething toys, grinding sticks, silicone spoons, and silicone baby food containers.
5. Medical and Health Industry
Silicone is non-toxic, biocompatible, and has good physical and mechanical properties. It can be sterilized at high temperatures without damage and has low blood clotting properties, making it ideal for medical applications. Silicone materials can be processed into various shapes, such as films, sponges, and airbags, and are widely used in the medical field. Products include blood transfusion tubes, various catheters, chest drainage tubes, cosmetic and repair materials, artificial skin, implantable materials, drug release systems, biosensors, and other medical devices. Silicone can also be used to make various human organs, such as artificial larynxes, artificial lungs, retinal implants, artificial heart valves, esophagus, trachea, artificial joints, prostheses, etc. Silicone can restore functions such as speech, eating, and breathing for patients who have had their larynx removed. The applications of silicone in the medical and health fields can be categorized as follows: long-term implants inside the human body, short-term medical devices, cosmetic medical devices, drug release systems, and external medical products.
6. Wire and Cable Industry
Silicone is an ideal insulation material for the wire and cable industry. High-temperature vulcanized silicone is resistant to high temperatures, ozone, weathering, and has excellent electrical properties. When silicone burns or decomposes, the silica residue still acts as an insulator. Silicone also has good thermal conductivity, enabling rapid heat dissipation generated by electrical current. It has excellent arc resistance, and silicone cables are widely used in power cables, marine cables, heating cables, ignition cables, atomic energy device cables, and aerospace wires. Adding aluminum hydroxide filler to silicone used in high-voltage insulated lines can enhance its resistance to leakage, electrical erosion, and electrical arcing.
7. Aerospace
Aerospace materials need to withstand long-term operation in temperatures from -75 to 200°C, as well as resist ozone, radiation, aging, and flame-retardant properties. Silicone is an indispensable high-performance material in the aerospace industry. Silicone materials can withstand the extreme cold of space and the intense heat during atmospheric re-entry, extending the lifespan of aircraft parts, reducing maintenance costs, and preventing accidents. Silicone is mainly used in aircraft body seals, electrical connectors, sealing switches, dustproof and waterproof covers, gaskets, O-rings for jet engines and hydraulic devices, oxygen masks, control membranes, hot air ducts, radar vibration isolators, and more. Heat-resistant silicone is used for rocket fuel valves, power source cables, and rocket launch pad coatings to prevent damage from rocket exhaust burns. Common silicone products in this field include hoses, sealing gaskets, seals, bellows, valve parts, vibration dampers, hot air ducts, switch covers, oxygen masks, fireproof partitions, soft hoses for instruments, buffer pads, wires, cables, plugs, sockets, and switch buttons.
8. Other Applications
Silicone films made from high-temperature vulcanized silicone have excellent breathability, which is tens or even hundreds of times greater than that of common polymer films (such as polyethylene, PVC, PTFE, etc.). Silicone films also have good selective breathability. These properties allow for the production of various silicone films used for air exchange windows, fresh-keeping bags for vegetables, fruits, and food storage, as well as gas separation devices. Silicone is also used in the production of printing and coating machine rollers, high-pressure cooker gaskets, and other sealing parts, gaskets, and washers for household items.
How to Choose a Silicone Factory?
The development and production of silicone products require significant effort and time. Due to the variety of silicone types and different manufacturing processes, a professional, careful, and responsible silicone factory is necessary to successfully achieve the product development goals. When you are looking for a silicone factory, there are several things you should consider:
1. Product Quality of the Silicone Factory
Choose a silicone factory with stable production and processing capabilities to ensure they meet your quality requirements. Understand whether the silicone factory has relevant certifications, such as ISO9001, ISO13485, or IATF 16949, to ensure the silicone products produced by the factory are stable and reliable.
2. Production and Technical Capabilities of the Silicone Factory
Consider the silicone factory’s production and technical capabilities, such as mold design and development ability, factory size, and employee count. Choose a factory with good mold design and development capabilities, as well as sufficient production capacity to ensure product compliance and production efficiency.
3. Product Pricing of the Silicone Factory
The product price is determined by the cost of raw materials and labor. Silicone raw materials come from leading imported brands from Japan, the USA, Germany, Korea, and others, as well as domestic brands from China, with significant price differences. Using high-quality silicone raw materials ensures product quality and stable production processes. Understand the factory’s production process, raw material quality, and technical capabilities to determine if the price they offer is reasonable.
4. Brand Reputation of the Silicone Factory
Brand reputation can be understood through the silicone factory’s customer cases. If the factory has worked with many well-known large companies, it indicates a certain level of competence. Choose a silicone factory with a good reputation to ensure the quality of the products you need.
5. Customer Service of the Silicone Factory
A professional and responsible liaison is a key factor in silicone product development. During the product development phase, the liaison should fully understand the client’s needs, respond quickly to inquiries, and provide specific, effective solutions. Choose a silicone factory with good customer service to ensure you receive support throughout the production process.
Conclusion
Dafeng Manufacture focuses on customized silicone development, and its production process has passed international ISO9001 certification. The silicone raw materials provided by Dafeng Manufacture meet FDA and LFGB food-grade standards and have been tested by Taiwan SGS. The company has many well-known clients in industries such as industrial, electronics, food processing, and medical equipment, making it a professional silicone factory and a leading Taiwanese silicone manufacturer, capable of offering you the most suitable product development services.
