Silicone products are widely used in industries, medical fields, and everyday life. Known for their heat resistance, corrosion resistance, waterproofness, flexibility, and environmental friendliness, silicone is extensively utilized in medical devices, food processing, renewable energy, and electronics. Today, I’ll introduce the hardness of silicone and its corresponding applications. Choosing the appropriate hardness of silicone is crucial for beginners as different hardness levels suit different scenarios.
Hardness is a key parameter that represents the material’s resistance to external forces pressing into its surface. It is felt as the softness when touched by hand, reflecting the material’s ability to resist certain deformations, especially plastic deformation, indentations, or scratches.
Silicone is a common polymer material available in various hardness levels, typically measured using the Shore A scale. The higher the Shore A value, the harder the silicone. Shore hardness is determined using a static compression measurement method, employing Shore A, C, and D durometers, each matching HA, HC, and HD units respectively. Liquid silicone and solid silicone rubber commonly use the Shore A scale.
Liquid and Solid Silicone Rubber
Common hardness levels range from Shore A0 to A70 for solid silicone rubber and Shore A30 to A70. There are also liquid silicone rubbers softer than Shore A0, but these are less commonly used and require custom orders measured with a Shore C durometer.
Liquid silicone rubbers are either manually controlled or machine controlled, with manually controlled types achieving hardness levels from 0 to 70 SSA, and machine-controlled types ranging from 20 to 90 degrees.
Higher hardness levels, over Shore A90, are measured using the Shore D durometer. These silicone rubbers are very hard but lack elasticity.
Differences Between Liquid and Solid Silicone Rubber
For intricate injection molds, solid silicone rubber is more suitable due to its demand for technical application and hot pressing equipment. Liquid silicone rubber can be manually processed, offering advantages in tensile strength for solid types and tactility for liquid types.
Appearance Differences between Liquid and Solid Silicone Rubber
From the appearance: one solid, one liquid.
1. Liquid silicone rubber is a fluid, highly transparent, reliable food-grade material used in manufacturing without adding curing accelerators.
2. Solid silicone rubber is a solid, transparent, environmentally friendly material requiring curing accelerators to speed up the vulcanization process.
Application Differences in Various Fields
1. Liquid silicone rubber is commonly used in mother and baby products, kitchen utensils, and medical devices as it is safe for contact with food and the human body.
2. Solid silicone rubber is generally used in everyday goods, decorative crafts, and automotive parts.
Common Silicone Rubber Hardness Levels
Silicone rubber comes in various hardness levels, usually measured in Shore A. Here are some common silicone rubber hardness levels and their applications:
1. 0-10 Shore A for extremely soft silicone molds used in food, realistic prosthetics like masks and sex toys, and soft gaskets.
2. 10-20 Shore A is very soft and comfortable, often used for personal accessories like breast prostheses, breast pads, and body-slimming garments.
3. 30-50 Shore A is relatively soft with good elasticity, suitable for items like phone cases, pacifier, baby teething toys, collapsible water bottle, insoles, and seals.
5. 50-60 Shore A offers a balance of softness and compression resistance, ideal for products like phone cases, earphone tips, and game controllers.
5. 70-90 Shore A is harder and more durable, used for items requiring high strength and wear resistance like automotive parts and tool handles.
In addition to hardness, other physical properties like tensile strength, elongation at break, and electrical properties like surface resistivity and relative dielectric constant are also crucial. Density affects the product’s weight and elasticity, and silicone products can withstand temperatures from -60°C to 250°C. When choosing silicone products, consider the chemical environment as they resist corrosion from acids, alkalis, and solvents. Silicone products can also be colored or finished to meet different aesthetic requirements. For more information on silicone products, pls contact Mitour Silicone.