What Materials Are E-Cigarettes Made From?

E-cigarettes are increasingly favored by smokers as a substitute for traditional cigarettes. As a product that mimics the experience of smoking, what exactly enables it to achieve the same taste, vapor, aroma, and sensation as traditional cigarettes?

The key lies in the e-liquid

To replicate the taste of traditional cigarettes, the composition of the e-liquid is crucial. E-liquid, also known as e-cigarette vapor liquid, is made from glycerin, propylene glycol, food flavorings, and plant extracts through processes such as mixing, resting, filtering, and packaging.

E-cigarette liquids use food-grade or pharmaceutical-grade propylene glycol (PG), which serves to dissolve flavorings, enhance the taste of the e-liquid, and also dilute glycerin, reducing the viscosity of the e-liquid for better wicking. Additionally, PG produces a small amount of vapor when heated and provides a throat hit, so e-liquids with a higher PG content generally have a richer taste and a stronger throat hit, but produce less vapor. Glycerin primarily serves to produce vapor in the e-liquid. When heated, glycerin generates a large amount of vapor, so to increase the vapor production of e-cigarettes, more glycerin needs to be added to achieve the desired effect.

Flavorings play a very important role in e-liquids; they can be considered the soul of the e-liquid. The flavor of the e-liquid is determined by the flavorings, and the combination and proportion of different flavorings dictate the flavor profile of a particular e-liquid.

In addition, various additives are included in e-liquids, such as sweeteners, sour agents, throat soothers, and deionized water. These additives primarily serve to improve the taste of the e-liquid and compensate for any shortcomings in the flavorings. For example, if a flavor is slightly bitter or sour, sweeteners can be added to enhance the taste. Deionized water is mainly used to dilute glycerin. Some e-liquids do not contain PG, and glycerin is very viscous, which can lead to poor wicking in some tank-style atomizers, so deionized water is used to dilute glycerin to improve the flow of the e-liquid.

So, how do e-cigarettes work? E-cigarettes use a battery to power a heating coil (resistance wire), generating heat to vaporize the e-liquid, allowing users to experience a sensation similar to smoking, achieving the effect of "exhaling vapor."

Engineering plastics form the framework

Anyone who has used an e-cigarette knows that it mainly consists of three parts: the battery, the atomizer, and the mouthpiece.

The atomizer is the core component of the e-cigarette, which vaporizes the e-liquid through heating, generating high temperatures of 200℃ to 300℃. Therefore, the atomizer and surrounding components must be made from materials that can withstand high temperatures and have good heat dissipation properties to endure the high temperatures of the vaporization process without being damaged due to heat accumulation. Additionally, the materials used must not produce any odors during heating that could ruin the flavor of the vapor, and they must have sufficient strength to withstand minor impacts or drops without breaking.

High-end e-cigarette atomizers often use polyether ether ketone (PEEK) for the oil chamber material. PEEK is a unique semi-crystalline thermoplastic with excellent chemical properties, commonly used in hot water or steam environments. It maintains high levels of bending and tensile strength, can withstand high temperatures (up to 260℃), and does not emit any odors at high temperatures, with good thermal conductivity. While PEEK meets all the requirements for atomizers, it is quite expensive, costing around 1000 yuan per kilogram.

The outer shell of high-end e-cigarette atomizers is often made from modified polyphenylsulfone (PPSU). PPSU is a new type of amorphous thermoplastic that is lightweight, strong, and has a pleasant odor at high temperatures. It does not contain bisphenol A and does not deform under repeated heating, making it suitable for long-term contact with water. Even when soaked in 90℃ hot water for a year, its mechanical properties do not decline. Atomizer covers made from PPSU can meet safety requirements under heated conditions. Additionally, PPSU is tough, has a good appearance for injection-molded parts, and provides a good tactile feel, meeting strength requirements for part insertion and improving positioning accuracy during assembly.

The battery and mouthpiece parts do not have as high requirements for plastic components; they only need to ensure good appearance, be paintable, and be able to be electroplated. The mouthpiece must meet food-grade requirements, be hard, and resistant to scratches. Therefore, the battery and mouthpiece are generally made from common plastics like PC, ABS, PP, and PE, which are inexpensive and can meet usage requirements after electroplating and painting.

Some high-end e-cigarettes use polyether imide (PEI) for the mouthpiece. PEI is a non-crystalline thermoplastic with high mechanical strength and rigidity, exhibiting excellent creep resistance over a wide temperature range and under prolonged high temperatures. It also has excellent hydrolysis resistance and dimensional stability, can withstand high temperatures of 200℃, and does not emit odors at high temperatures, with good thermal conductivity and safety.

Additionally, some brands use polyoxymethylene (POM) for the mouthpiece, commonly known as super steel or acetal, which has high strength and rigidity, good elasticity, and wear resistance, making it suitable for long-term use within a temperature range of -40℃ to 100℃.

Silicone materials ensure waterproofing

E-cigarettes are electronic products that need to be waterproof, dustproof, and drop-resistant to protect the internal electronic components and ensure their lifespan. The body of e-cigarettes is typically manufactured using metal-plastic composite molding, TPU or TPE soft rubber two-color injection molding, or silicone rubber molding. Special protective treatments are applied to battery compartment covers and electrical interfaces to achieve the "three-proof" effect of waterproofing, dustproofing, and drop resistance.

Some e-cigarette bodies are made using a method that wraps a metal frame with soft rubber. This method involves placing the metal frame in a mold and injecting a layer of TPU or TPE soft rubber around it. TPU soft rubber has high wear resistance, good processing performance, oil resistance, water resistance, and is non-toxic and odorless, allowing for silk-screen printing and processing.

The buttons on ordinary e-cigarettes have gaps between them and the body, making them susceptible to dust and water ingress. Therefore, buttons are typically made using silicone integrated molding or waterproof structural adhesive assembly to achieve waterproof and dustproof effects. Silicone rubber has excellent electrical insulation and fatigue resistance, and the buttons are integrated with the silicone layer, ensuring effective waterproofing and dustproofing while providing a tactile feel. The battery compartment cover is equipped with a transparent silicone waterproof sealing ring, which deforms under pressure to seal the threaded gaps, providing waterproofing. The USB charging port is fitted with a soft rubber plug, which tightly fits with the USB socket to provide dustproofing and waterproofing.