Rubber foam, with its closed cell structure and high porosity, has excellent electrical insulation and heat insulation, and is widely used in the fields of architecture, electronics and cold chain, becoming an efficient energy-saving material.
In the modern society that pursues high efficiency and energy conservation, the choice of insulation materials directly affects energy utilization efficiency and safety. Rubber foam, as a lightweight porous material, has attracted much attention in the fields of construction, electronics, transportation and so on in recent years. Does it have excellent insulation performance? This article will analyze from the perspectives of electrical insulation, thermal insulation, and practical applications.
1〠Material properties of rubber foam
The rubber foam takes synthetic rubber (such as nitrile rubber, neoprene) or natural rubber as the base material, and forms a uniform closed cell structure through the foaming process. It contains a large number of independent pores inside, with a porosity of up to 80% -95%. This structure endows the material with the following characteristics:
Lightweight: The density is usually between 30-200 kg/m ³, making it easy to transport and install;
Flexibility: can adapt to the fitting of complex shaped surfaces;
Corrosion resistance: acid and alkali resistance, moisture resistance, long service life.
2〠Electrical insulation performance: an ideal choice for blocking current
The electrical insulation of rubber foam comes from its chemical structure and physical form:
Polymer barrier: Carbon carbon bonds and cross-linking structures in rubber molecular chains hinder electron migration, with a volume resistivity of up to 10 ¹² -10 ¹âµΩ· cm, close to the level of ceramic insulators;
Closed cell isolation: Independent pores reduce conductive channels, ensuring stable insulation even in high humidity environments;
Voltage endurance strength: can withstand an electric field strength of 10-30 kV/mm, commonly used in scenarios such as cable sheaths and electronic equipment compartments.
Application case: In the battery pack of new energy vehicles, rubber foam wraps the battery cell, which not only prevents short circuit but also relieves shock.
3〠Thermal insulation performance: efficient blocking of heat transfer
The thermal insulation capacity of rubber foam is jointly affected by the following mechanisms:
Low thermal conductivity: the static air thermal conductivity is only 0.026 W/(m · K), while the overall thermal conductivity of rubber foam is as low as 0.035-0.045 W/(m · K) due to closed pores, which is better than most organic foam (such as EPS foam 0.04-0.06 W/(m · K));
Radiation reflection: rubber foam with aluminum foil coating can reflect more than 90% of thermal radiation, which can reduce the indoor temperature by 5-8 ℃ when used for roof insulation;
Heat resistance convection: The closed cell structure suppresses air flow and reduces convective heat dissipation.
Experimental data: According to the test of New Building Materials in 2023, the heat flow density of 3cm thick rubber foam board is only 12 W/m ² at a temperature difference of 70 ℃, and the heat insulation efficiency is 20% higher than that of rock wool.
4〠Advantages and limitations in practical applications
advantage
Multifunctionality: Simultaneously meet the insulation requirements of electricity, heat, and sound;
Environmental friendliness: Some products are made of recycled rubber and comply with green building standards;
Convenient construction: can be prefabricated into rolls or sheets, and supports on-site cutting.
limitation
Temperature resistance range: The long-term use temperature generally does not exceed 120 ℃, and it is prone to aging at high temperatures;
Flammability: Flame retardants (such as aluminum hydroxide) need to be added to enhance the fire rating;
High cost: the unit price is 30% -50% higher than that of polystyrene foam.
5〠Industry trend: innovative breakthrough of rubber foam
In 2024, a science and technology company developed the "nanocomposite rubber foam". By doping graphene aerogel, the thermal conductivity was reduced to 0.022 W/(m · K), and the flame retardant grade reached UL94 V-0. This material has been used in the construction of ultra-low temperature cold storage and still maintains flexibility in an environment of -50 ℃.
conclusion
Rubber foam, with its unique closed cell structure and adjustable performance, has shown significant advantages in the field of electrical and thermal insulation. Despite the limitations of cost and temperature resistance, with the advancement of material modification technology, its application prospects in fields such as new energy and green buildings are broad. In the future, rubber foam with high efficiency insulation and sustainability may become one of the key materials for low-carbon economy.