Silicone Radiator Hoses

The purpose of this article is to conduct an in-depth analysis of silicone radiator hoses, covering various aspects such as material, characteristics, types, applications, advantages, and disadvantages. It aims to provide sellers and professionals with insights and knowledge about the various performance aspects of silicone radiator hoses from the perspective of production manufacture, enabling a better understanding of the product.

What Is A Silicone Radiator Hose Made Of?

The silicone radiator hose is made of silicone rubber, which refers to rubber where the main chain is composed of alternating silicon and oxygen atoms, with silicon atoms typically bonded to two organic groups. Ordinary silicone rubber is mainly composed of silicon-oxygen chain segments containing methyl and a small amount of vinyl groups. The introduction of phenyl groups can improve the high and low-temperature resistance of silicone rubber, while the introduction of trifluoropropyl and cyano groups can enhance its temperature and oil resistance. Silicone rubber has excellent low-temperature resistance and can generally operate at -55°C. With the introduction of phenyl groups, it can reach as low as -73°C. Silicone rubber also exhibits outstanding heat resistance, is capable of long-term operation at 180°C, and can still be elastic for several weeks or longer at slightly higher temperatures, withstanding temperatures above 300°C momentarily. Silicone rubber has good breathability, with oxygen permeability being the highest among synthetic polymers.

Definition of High-temperature Vulcanized Silicone Rubber

High-temperature vulcanized silicone rubber refers to the process where polydimethylsiloxane becomes an elastic material through high-temperature (110-170°C) vulcanization molding. It primarily uses high-molecular-weight polydimethylvinylsiloxane as the raw rubber, mixed with reinforcing fillers, vulcanizing agents, etc., and undergoes vulcanization into an elastic material under heating and pressure. The reinforcement of silicone rubber mainly involves various types of fumed silica, which can increase the strength of the vulcanized rubber by several tens of times. Sometimes, in order to reduce costs or improve the performance of the rubber compound and impart various special properties to the vulcanized rubber, various additives are also added accordingly. Vulcanizing agents include various organic peroxides or additional reaction catalysts.

Silicone Rubber Main Properties:

(1) High-temperature performance: The significant characteristic of silicone rubber is its high-temperature stability. Although the strength of silicone rubber at room temperature is only half of natural rubber or certain synthetic rubbers, it can still maintain a certain degree of flexibility, resilience, and surface hardness at temperatures above 200°C, with no significant change in mechanical properties.

(2) Low-temperature performance: The glass transition temperature of silicone rubber is generally between -70°C and -50°C, and with special formulations, it can reach as low as -100°C, indicating excellent low-temperature performance. This is of great significance to the aerospace industry.

(3) Weather resistance: The Si-O-Si bonds in silicone rubber are highly stable to oxygen, ozone, and ultraviolet radiation. Even without any additives, silicone rubber exhibits excellent weather resistance.

(4) Electrical properties: Silicone rubber has excellent insulation properties, as well as good resistance to corona discharge and arc discharge.

(5) Physical and mechanical properties: The physical and mechanical properties of silicone rubber at room temperature are inferior to those of general rubber. However, at high temperatures of 150°C and low temperatures of -50°C, its physical and mechanical properties are superior to those of general rubber.

(6) Oil, fuel, and chemical resistance: Ordinary silicone rubber has moderate resistance to oil and solvents.

(7) Gas permeability: At room temperature, silicone rubber has 30-50 times higher gas permeability for air, nitrogen, oxygen, carbon dioxide, and other gases compared to natural rubber.

(8) Biocompatibility: Silicone rubber is non-toxic, odorless, and tasteless. It does not adhere to human tissues, exhibits anti-coagulation properties, and elicits minimal reaction from bodily tissues. It is particularly suitable for use as medical materials.

Silicone Radiator Hose Production Process

(1) Silicone rubber material mixing:  the raw material of silicone rubber is pure white color. Firstly, put the white silicone rubber raw material on the roller of the mixer, then add the pigment and vulcanizing agent. The machine roller starts to work, and as the roller rolls, the originally hard silicone rubber material begins to soften, and the color starts to become uniform.

(2) Calendering: calendering is achieved through the rotation of the roller, increasing pressure and temperature, flattening and smoothing the surface of the silicone rubber raw material while adjusting the distance between the rollers to adjust the thickness of the silicone rubber sheet. Normally, the hose layer thickness is 1.25 mm.

(3) Fabric cutting: after finishing the calendering material sheet, cut these sheets into small and exact sizes of sheets.

(4) Forming: the silicone radiator hose is produced by hand by rolling each layer into a hose with a mold tool.

(5) Heating & Vulcanization: put the hoses formed into the oven and heat until the temperature reaches 170℃, it takes about 1 hour, then cool down.

(6) Demoulding: remove the silicone tubes from the mold using auxiliary tools or a high-pressure water gun.

(7) Hose cutting: measure, mark, and position the length of the tubes, then use auxiliary molds to insert the tube ends and cut off the excess length.

(8) Logo print: labeling and printing the hoses that the customer supplied.

(9) Quality control: inspect and report all finished silicone radiator hoses with trackable files.

 

Silicone Radiator Hose Application

• car and truck engine radiators, water tanks, and water pumps
• motorcycle engines radiator hoses
• airplane engines

How Silicone Radiator Hose Improve Cooling?

As is well known, the temperature range of EPDM hoses is inferior to that of silicone radiator hoses, with a range from -40°C to +125°C. This means that for applications such as engine radiators, cooling systems, or exhaust systems, silicone hoses would be the optimal choice.

Furthermore, compared to EPDM hoses, silicone radiator hoses are more flexible and durable, with smoother surfaces and a wider range of colors. They also exhibit stronger resistance to aging, resulting in a longer lifespan.

What Is the Disadvantages of Silicone Material?

The disadvantages of silicone rubber mainly include:

1. Low tensile strength and tear resistance, making it perform the worst among all rubber materials.
2. Low abrasion resistance, unsuitable for applications requiring heavy loads.
3. Poor resistance to acids and alkalis, especially unable to withstand aliphatic hydrocarbons and aromatic oils.
4. Difficult to process, the high hardness and elasticity of silicone rubber make processing somewhat challenging.
5. High cost, mainly due to the high cost of silicone rubber materials and complex production processes.
6. Susceptible to aging, leading to hardening, cracking, etc., after long-term use, affecting lifespan and safety.
7. Poor oil resistance, unable to withstand many organic solvents and oils, limiting its use in specific industrial applications.

It's worth noting that although silicone rubber has some disadvantages, it also possesses other excellent properties such as heat resistance, low-temperature elasticity, and resistance to oxidation and ozone. Therefore, when choosing to use silicone rubber, its advantages and disadvantages should be considered comprehensively, along with the specific requirements of the application.

Why Silicone Radiator Hose Better Than OEM?

As per above silicone rubber material properties,it have much better performance in temperature range and flexibility and smooth surface, so silicone radiator hose is best choice comparing to OEM rubber hose.

What Is the Lifespan of Silicone Radiator Hose?

The silicone radiator hose average lifespan is 20 years, normally, it’s guaranteed to be 10 or even 15 years without a problem for some vehicle owners. Also,it’s up on the situation of usage.

4 Facts You Need to Consider Before Purchasing Motorcycle Silicone Radiator Hose

Temperature: the temperature of silicone radiator hose range is from -55°C to 270°C, so it can withstand much higher temperature fluids than standard EPDM rubber radiator hose. 

Damage: consider several damages for silicone radiator hose, hose clamps, friction, screwdriver, knife and other metal tools.

Acids and Alkalis Chemical: the silicone radiator hose can not resist acids and alkalis chemical, so consider the usage situation before your buying.

Oil and Fuel: the standard silicone radiator hose can not withstand oil and fuel.

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