In the silicone industry, liquid silicone rubber (LSR) generally refers to vinyl polysiloxane made of high-temperature curing of two components. Usually, liquid silicone products are catalyzed by platinum, through pouring or injection molding.

Compared with high-temperature vulcanized solid silicone rubber, liquid silicone rubber does not need mixing, has low energy consumption, a short molding cycle, and high production efficiency, the required production site is small, and it can achieve a fully automated process. The curing mechanism of liquid silicone rubber determines that its curing process will not produce byproducts, and the finished product has a small shrinkage rate, can be deeply cured, and has better physical and electrical properties. In addition, because liquid silicone rubber has thixotropy, low viscosity at a high shear rate, and good fluidity, it is especially suitable for the preparation of fine products and can realize the manufacture of products with various complex shapes.

Liquid silicone rubber has many performance advantages and processing convenience greatly broadens its application field so that it has become a silicone material variety with rapid development, higher grade, higher product technology content, and higher added value in recent years. At present, liquid silicone rubber is mainly used in the fields of pregnancy and baby products, medical supplies, electronics and electrical, automobile, and daily consumer goods, and with the change of market demand and technological progress and continuous development.

• Low VOC content is the general trend of sensitive applications

The medical and health field including infant care is the largest application market of LSR. According to the statistics of a related report, the consumption of LSR in the domestic medical and health market in 2022 was about 27,000 tons. Due to its good biocompatibility, LSR is mainly used in milk bottles, pacifiers, medical catheters, medical device jackets, and cosmetic prostheses.

Infant care, medical care, and food contact are all sensitive application areas, and relevant legislative bodies have set strict purity standards to ensure product safety, such as “XV. Organosilicon “, the French decree of 25 November 1992, Swiss Regulation 817.023.21 on Contact Materials and Products for food and the European standard EN14350-2 for drinking equipment for infants and young children and EN1400 for pacifiers, etc.

medical silicone parts

These regulations use the weight loss of silicone products after special heat treatment (usually at 200°C for 4 hours) as a measure of VOC content. During heat treatment, the weight loss of the molded part sample after drying shall not exceed 0.5% of its mass. Cured products of ordinary liquid silicone rubber must be secondarily vulcanized to meet the above regulations. However, secondary vulcanization not only leads to a lot of energy consumption but also will have the risk of cross-contamination and will affect the automatic production process.

• Self-adhesive, low friction to meet the development needs of consumer electronic products

The electronics and electrical industry is currently the second-largest application market of LSR. Related data showed that in 2022, the consumption of LSR in the domestic electronics and electrical industry was about 10000 tons, an increase of 8.9% year-on-year. In the next five years, the consumption of LSR in the electronics industry is expected to grow at an average annual rate of 8.9% and will reach 15,000 tons in 2024. Due to its excellent dielectric properties, LSR is widely used for sealing electronic components, insulating the protection of high-voltage circuits, and sheathing consumer electronic products.

In recent years, the consumer electronics field represented by mobile phones, tablets, and wearable devices has developed rapidly. Liquid silica gel is widely used in the field of consumer electronics due to its excellent waterproof performance, elasticity, anti-aging, non-toxic and harmless, and other advantages, with huge market potential.

Especially with the continuous upgrading of the function and performance of consumer electronics, its design is becoming more and more “compact”. With the special ability of composite molding with metal inserts and plastics, liquid silicone rubber has also become the preferred material for structural components of consumer electronics.

At the same time, the feel of consumer electronics, especially wearable devices, has attracted much attention as consumers’ demand for quality increases. Feel smooth, easy to clean, and dust the structural materials are increasingly popular in the market.

• Self-permeating silicone oil-assisted automobile digitization and intelligence

Automotive is also an important application market for liquid silicone rubber. Liquid silicone rubber in automotive applications mainly focuses on various seals, as well as O ring and spark plug protective covers. According to the data estimated that the consumption of LSR in the automotive sector in 2022 was about 3100 tons. In recent years, with the development of digitization and intelligence, cars need to carry more wire harnesses, and higher requirements are put forward for the assembly of wire harnesses.

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