Silica gel (silica gel; Silicon rubber is a kind of high-activity adsorption material, which belongs to amorphous substance, and its chemical molecular formula is mSiO2 nH2O. Insoluble in water and any solvent, non-toxic, tasteless, chemically stable, and does not react with any substance except strong alkali and hydrofluoric acid. Different types of silica gel have different micropore structures due to different manufacturing methods.
silica gel
The chemical composition and physical structure of silica gel determine that it has many irreplaceable characteristics: high adsorption performance, good thermal stability, stable chemical properties and high mechanical strength. Silica gel is divided into macroporous silica gel, coarse silica gel, B-type silica gel and fine silica gel according to pore size.
At present, there are two kinds of silicone sleeves, one is silicone and the other is inorganic silicone. At present, the silicone rubber sleeves of digital products on the market basically belong to silicone rubber. It has the characteristics of high temperature resistance, good weather resistance (not afraid of ultraviolet rays or ozone decomposition), good insulation and stable material.
Advantages: low price, high adsorption performance, good buffering performance, not easy to wear and comprehensive protection.
Disadvantages: thick texture, few styles, easy to get greasy, and slightly poor fit with the fuselage. At the same time, materials with slightly poor quality are easy to dust and enter the dust.
Silicone cover also has a good feel, and some mobile phones with stiff buttons will be improved after covering the silicone cover. It can also absorb the impact of some bumps on the mobile phone and reduce the damage to the mobile phone to a certain extent. In addition, the silicone sleeve also has good waterproof performance, which has become one of its biggest selling points. The silicone sleeve itself is slightly sticky, which will absorb a lot of dust on the mobile phone after a period of use. In the long run, it is not conducive to the beauty of mobile phones and runs counter to the original intention of protecting mobile phones.
What is TPU material?
TPU is the main material for making water jacket, which is short for thermoplastic polyurethane elastomer. The so-called elastomer refers to a polymer material with glass transition temperature lower than room temperature, elongation at break >: 50% and good resilience after external force is removed. Polyurethane elastomer is a special kind of elastomer. Polyurethane elastomer has a wide range of hardness and properties, so polyurethane elastomer is a polymer material between rubber and plastic. Heating can plasticize, with little or no cross-linking in chemical structure, and the molecules are basically linear, but there are some physical cross-links. This polyurethane is called TPU.
TPU raw materials
As an elastomer, TPU is a material between rubber and plastic, which is oil-resistant, waterproof and mildew-proof. TPU products have excellent bearing capacity, impact resistance and shock absorption. TPU belongs to plastic, and the product is made by injection molding technology, that is, plastic rice is heated and melted, and then shot into a plastic mold with a gun barrel to make the product.
Advantages: high wear resistance, high strength, outstanding cold resistance, oil resistance, water resistance, mildew resistance and good flexibility.
Insufficient: easy to deform and turn yellow.
In terms of hand feeling, the hardness of TPU is generally harder than that of silicone, and the elasticity of silicone is stronger when it is pinched by hand, but the elasticity of silicone is slightly worse. From the outside, TPU can be made transparent, but silicone can't. The most transparent thing is the hazy feeling like dense fog. It is precisely because of this transparency of TPU that it is now more popular with users. Moreover, there are many high-grade TPU products, which are more selective than silica gel and have many patterns.