8 Plastics Commonly Used in E-Cigarette Structural Parts

An e-cigarette is an electronic device that mimics a traditional cigarette and is designed to provide a smoking-like experience. It produces vapor for users to inhale by heating a liquid containing nicotine, propylene glycol, glycerin, and various flavors.

E-cigarettes are usually composed of batteries, atomizers, and smoke liquids, which can avoid the harmful substances produced when traditional cigarettes burn. Due to their smoke-free, tar-free, and less odor, e-cigarettes are regarded as a harm-reducing alternative to traditional smoking.

8 common plastics for e-cigarette structural parts

The plastic parts of e-cigarettes usually include shells, mouthpieces, and other internal components. Here are some common plastic parts and their characteristics:

1. Shell: The shell of an e-cigarette is usually made of durable plastic materials to protect the internal electronic components. Common materials include ABS (acrylonitrile-butadiene-styrene) and PC (polycarbonate), which have good impact resistance, heat resistance, and chemical resistance.

2. Mouthpiece: The mouthpiece is the part of the e-cigarette that contacts the user, and usually uses food-grade plastic materials such as PCTG (copolyester) or PEEK (polyetheretherketone). These materials are resistant to high temperatures, corrosion and non-toxic, and can meet the safety requirements of oral contact.

3. Oil tanks and oil reservoirs: These parts are used to store e-cigarette oil, and usually use transparent and chemically resistant plastics such as PCTG or PEEK. This allows users to easily check the remaining amount of oil.

4. Internal components: Some small components inside the e-cigarette may also be made of plastic, such as battery compartments, fixed brackets, etc. The materials used for internal plastic parts usually emphasize high temperature resistance and chemical corrosion resistance to ensure the safety and durability of the device.

The selection of these plastic parts mainly considers their chemical stability, high temperature resistance, non-toxicity and mechanical strength to ensure the overall performance and safety of e-cigarettes. Among them, the types of plastics used are PCTG, PPSU, PP, PC, PEEK, transparent nylon, etc.

1. PCTG

PCTG has the advantages of glass-like transparency and density close to glass, does not contain bisphenol A, and has excellent food hygiene and flame retardancy. It was previously used in cosmetic packaging and plastic water cups. At present, it is used in most e-cigarette oil tanks, mouthpieces, and cigarette rod shells, and the demand is huge.

8 common plastics for e-cigarette structural parts

PET resin is a linear homopolymer formed by the polycondensation of diols (ethylene glycol, EG) and dibasic acids (terephthalic acid, PTA), while copolyesters are polyesters modified with alcohols or acids, including PETG, PCTG and PCTA, as well as degradable copolyesters. PCTG is a non-crystalline copolyester. In its production process, a certain amount of ethylene glycol is replaced by 1,4-cyclohexane dimethanol (CHDM), which can prevent crystallization and improve processing and transparency.

8 common plastics for e-cigarette structural parts

Currently, high-end flagship products of e-cigarettes are using PCTG materials, mainly used in mouthpieces, oil tanks and even shells.

8 common plastics for electronic cigarette structural parts

2. PPSU

PPSU is a new type of non-crystalline thermoplastic engineering plastics, which is light, high-strength, and has a good smell at high temperatures. It does not contain bisphenol A, will not denature even under repeated heating, has good sterilizability, and can be in contact with water for a long time. And one of its typical applications is baby bottles, so it is also called "bottle material".

Polyphenylene sulfone PPSU is synthesized from 4,4′-biphenylene phenol and 4,4′-dichlorodiphenyl sulfone through salt formation, polycondensation and other steps. The molecular structure is as follows:

8 common plastics for electronic cigarette structural parts

Structural formula of PPSU resin
8 common plastics for electronic cigarette structural parts

Figure IQOS upper cover shell uses PPSU modified material (source network)

3. PEEK

PEEK is a thermoplastic special engineering plastic. Due to its good mechanical properties, high melting point and biocompatibility, it is non-toxic and meets FDA certification. Polyetheretherketone (PEEK) refers to a linear aromatic semi-crystalline polymer whose main chain consists of aromatic, ketone and ether bonds, and is a polymer family of "aromatic polyketones".

8 common plastics for electronic cigarette structural parts
Figure PEEK structure

PEEK is currently used in the field of heat-not-burn electronic cigarettes for heat-not-burn electronic cigarette shells, heating plate bases, atomization chambers and other parts. In addition to the use of PEEK materials in the shell and heating base of IQOS, QOQ of Yanwa Technology and CIGRIG of Sigeruige also use PEEK materials for smoking parts.

8 common plastics for electronic cigarette structural parts

Figure PEEK heating accessories around electronic cigarettes

Fourth, transparent nylon

Excellent transparency (transparency even exceeds PC and is close to PMMA). On the other hand, it is superior to general transparent polymer materials (such as PS, PC, PMMA, etc.) in terms of environmental stress cracking resistance, oil solvent resistance, scratch resistance, and wear resistance. Common types of transparent nylon include PA MACM12, PA 12/MACMI, PA 6I/X, etc.

8 common plastics for electronic cigarette structural parts

PA12 structural formula

V. PP

Polypropylene is a semi-crystalline thermoplastic. It has high impact resistance, strong mechanical properties, and is resistant to corrosion by a variety of organic solvents and acids and alkalis. With good performance, PP is the only plastic that can be put into a microwave oven. It has high strength and bending resistance (50,000 times) and will not break at -20°C.

VI. PEI

PEI, whose scientific name is polyetherimide, is a non-crystalline thermoplastic with high mechanical strength and stiffness. It has very high creep resistance over a wide temperature range and long-term high operating temperature. In addition, it has very good hydrolysis resistance and dimensional stability. The disadvantage is that the price is slightly higher.
8 common plastics for electronic cigarette structural parts

PEI structural formula

PEI is mainly used in mid-to-high-end atomizer mouthpieces.

8 common plastics for electronic cigarette structural parts

VII. POM

Polyoxymethylene POM, commonly known as "super steel" or "saigang", has a smooth, shiny, hard and dense surface. It is a light yellow or white appearance. It is an engineering plastic with excellent comprehensive performance after polyamide PI and one of the five general engineering plastics.

POM has good mechanical properties and rigidity, and can be combined with metal materials; POM has excellent fatigue resistance and creep resistance; good wear resistance, self-lubrication and friction resistance; currently it is widely used in electronic cigarette mouthpiece materials.

VIII. PC

PC material has transparency, good impact resistance and good dimensional stability, and is used in electronic cigarette atomizers and mouthpieces. It is understood that the transparent mouthpiece of E-hose electronic hookah uses a PC plastic mouthpiece, and some electronic cigarette brands also use PC material for the shell of the cigarette cartridge.

8 common plastics for electronic cigarette structural parts

From research and development to production, the use of highly safe and secure materials for electronic cigarette products is conducive to the healthy and orderly sustainable development of products. With the strengthening of electronic cigarette quality control, the industry will enter a new stage of development.