Process performance and application of fluorosilicone tube

Fluorosilicone rubber has excellent oil and solvent resistance. It has good stability at room temperature and high temperature for aliphatic, aromatic and chlorinated hydrocarbon solvents, various petroleum based fuel oils, lubricating oils, hydraulic oils and some synthetic oils (such as diester lubricating oils, silicate ester hydraulic oils, etc.), and can also maintain elasticity. Fluorosilicone rubber is a kind of side chain modified silicone elastomer. Generally, the products made of fluorosilicone rubber not only have the characteristics of general silicone rubber, but also have excellent oil resistance, including fuel oil, engine oil, chemical reagent and solvent. Therefore, fluorosilicone rubber can make up for the lack of oil resistance of ordinary silicone rubber, and can be called "oil fighter" in silicone elastomer.
 

Characteristics of fluorosilicone rubber
 

1. Oil, solvent and chemical resistance

Compared with methyl vinyl silicone rubber, fluorosilicone rubber has excellent oil resistance, solvent resistance and chemical resistance; even compared with fluorosilicone rubber, it has good oil resistance and solvent resistance. It can be said that fluorosilicone rubber is the only kind of non-polar medium resistant elastomer at - 60 ℃ ~ 260 ℃. Even in the gasoline / methanol mixed system, the hardness, tensile strength and volume change of the vulcanizates are very small. After 500 hours of long-term immersion test, the physical properties of the vulcanizates are almost unchanged.

2. Heat resistance

The high temperature decomposition of fluorosilicone rubber is the same as that of silicone rubber, that is, side chain oxidation, main chain fracture, side chain thermal decomposition and various complex reactions. Because the decomposition products can also cause the main chain fracture, the heat resistance of silicone rubber is usually worse than that of silicone rubber, and it has begun to oxidize at 200 ℃. However, by adding a small amount of heat stabilizers such as iron, titanium, rare earth oxides and so on, it can be significantly improved and has enough heat resistance even at 250 ℃. The effect of temperature on fluorosilicone rubber is greater than that of silicone rubber.

3. Cold resistance

Fluorosilicone rubber has the same low temperature performance as ordinary silicone rubber. Because fluorosilicone rubber is a linear polymer with soft Si-O as the main chain, its low temperature properties are better than those of fluorosilicone rubber with C-C as the main chain. Among them, fluorosilicone rubber has better low-temperature characteristics, and its brittleness temperature is as low as - 89 ℃, while ordinary fluorosilicone rubber is about - 30 ℃.

4. Electrical performance and radiation resistance

The electrical properties of fluorosilicone rubber are similar to that of ordinary silicone rubber, but the most valuable thing is that it has little change under harsh conditions such as high temperature, low temperature, humidity, oil, solvent, chemicals and ozone. The radiation resistance of fluorosilicone rubber is not outstanding, but the radiation aging resistance is better than that of methyl vinyl silicone rubber.

The radiation resistance of fluorosilicone rubber is not outstanding, but the radiation aging resistance is better than that of methyl vinyl silicone rubber.

5. Physical and mechanical properties

The mechanical strength (especially tear strength) of fluorosilicone vulcanizate is lower than that of ordinary silicone rubber. Therefore, improving the strength of fluorosilicone rubber is also an important research topic.

6. Other characteristics

The weather aging resistance of fluorosilicone rubber is very good, even after 5 years of exposure, it still has good performance. Ozone is one of the most common gases produced during the aging of elastomers, but no cracks or cracks were found in fluorosilicone rubber after dynamic or static tests. In addition, the antifungal, physiological inertia and anticoagulant properties of fluorosilicone rubber are also very good.
 

Application of fluorosilicone rubber:
 

1. Automobile industry:

All kinds of vehicles, turbocharger pipe, extrusion strip, seal ring, oil seal, diaphragm, pipe, valve lining, etc.

2. Petrochemical industry:

All kinds of high temperature, low temperature, chemical erosion resistant pumps, valves, oil tanks and other equipment sealing products.

3. Aviation industry:

Aircraft fuel oil, lubricating oil resistant seals, contacts, such as a variety of O-rings, fillers, sealing rings, sensor materials, diaphragm, gasket clamp.

4. Medical and health services:

For medical devices and artificial organs, such as medical catheter, drainage tube, artificial valve, etc.

5. Military industry

In the harsh environment of low temperature / oil / acid resistance, such as hydraulic system of military aircraft, infusion bellows, door and window / back cover sealing strip of special vehicles, sensor materials.
 

Special sealing strip for fluorosilicone edible oil:
 

1、 Classification of fluorosilicone

Fluorosilicone rubber is obtained by vulcanization of fluorosilicone raw rubber after adding vulcanizing agent and various reinforcing fillers. Generally speaking, fluorosilicone rubber refers to perfluorosilane rubber. There are many kinds of fluorosilicone rubber. The mass-produced fluorosilicone rubber is mainly a polymer with y-trifluoropropylmethylsiloxane as structural monomer.

According to the vulcanization mechanism, it can be divided into free radical type, condensation type and addition type;

According to vulcanization temperature, it can be divided into high temperature vulcanization type, room temperature vulcanization type and room temperature vulcanization type.

2、 Processing technology of fluorosilicone

The processing technology of fluorosilicone: mixing - heat treatment - Filtration - reverse refining - vulcanization

Mixing

Although fluorosilicone rubber is a solid, it has high plasticity and can be directly mixed in open mixer or internal mixer without plasticizing.

heat treatment

The main purpose of heat treatment is to further combine the structure control agent with silica and eliminate the low molecular volatiles.

filter

For extruded products, calendered products, glued products and diaphragm products, mechanical impurities and undivided particles are one of the main factors leading to product quality problems. Therefore, the rubber used in the above products must be filtered.

Return to refining

When the rubber is stopped, the gel content increases and the plasticity decreases, so it is necessary to refine it when used.

vulcanization

Fluorosilicone rubber is different from other ordinary rubber, vulcanization is divided into one stage and two stages. One stage curing time is short (1.5 ~ 15min), which can only make the product reach the degree of setting; after two-stage curing (3 ~ 6h), it can reach complete vulcanization, and the physical properties of vulcanizate can tend to be stable.

3、 Customized fluorosilicone in Dongguan Litop

Low compression, high rebound, high-end fluorosilicone tube