Liquid silicone rubber and commonly referred to as ordinary silicone in the industry, although both belong to the category of organic silicone elastomers, there are many essential differences between the two in terms of basic form, processing logic, performance, and applicable scenarios. Many downstream users easily confuse the two when selecting, ultimately leading to product quality not meeting expectations and even batch production failures. From the most basic physical form, the difference between the two is very intuitive.

Liquid silicone rubber presents a uniform and flowable liquid state before vulcanization, and its viscosity can be flexibly adjusted according to formula design, from thin low viscosity fluids to thixotropic pastes, which can be directly put into processing without the need for complex mixing processes in advance; Ordinary silicone mostly refers to traditional solid-state high-temperature vulcanized silicone rubber, which is a solid rubber block with certain elasticity before processing. Its hardness is generally high and it has no fluidity. It must be mixed for a long time in an open or internal mixer, mixed with vulcanizing agents and various functional fillers, before proceeding with subsequent molding processing.


The difference in processing methods is one of the core differences between the two. The low viscosity characteristics of liquid silicone rubber make it perfectly suitable for automated injection molding processes. The rubber material can be accurately transported to the injection machine barrel through a precision metering pump and maintained in a stable state in the low-temperature flow channel. After high-speed injection into the heated mold cavity, vulcanization can be quickly completed in tens of seconds to minutes. The entire production process produces almost no waste and does not require additional cleaning of the sprue material. The production efficiency is extremely high, especially suitable for the production of large quantities of precision small parts. The dimensional accuracy of the product can be controlled at the micrometer level, and there is almost no need for subsequent trimming treatment.

The processing flow of ordinary solid silicone gel is much more complicated. The mixed rubber material needs to be cut into corresponding weights of rubber blanks, manually placed into the mold cavity, and then pressed and vulcanized by a large flat vulcanizing machine under high pressure and high temperature. The filling process completely relies on external pressure to push the rubber material flow, making it difficult to fill into the extremely complex micro mold cavity. The molding cycle generally takes more than ten minutes, and a large amount of manual trimming is required afterwards. The production efficiency and product accuracy are far lower than those of liquid silicone rubber processing technology.


In terms of performance after vulcanization, the two also show significant differences. The linear shrinkage rate of the cured product of liquid silicone rubber is generally less than 0.1%, and its dimensional stability is excellent. It can maintain stable high elasticity in a wide temperature range of -60 ℃ to 250 ℃. The temperature resistance upper limit of some special modified grades can be further improved. The material's tear strength and high-temperature compression permanent deformation resistance are excellent, and there will be almost no obvious deformation during long-term use. The dielectric properties can also remain stable in high temperature environments, far better than the performance of ordinary organic rubber.

Although the temperature resistance upper limit of ordinary solid silicone can also reach the range of 200 ℃ to 300 ℃, due to the limitations of traditional molding processes, the density inside the product is often not as good as that of liquid silicone rubber products. Thick walled products are prone to uneven internal vulcanization, and the compression permanent deformation rate after long-term use is relatively higher. Some low hardness ordinary silicone products are also prone to decreased rebound performance and permanent deformation.