Liquefied gas propellants are stored as liquids under pressure but vaporise when released, maintaining consistent pressure throughout the product’s use. Examples include hydrocarbons (butane, propane) and DME. These are ideal for sprays requiring steady pressure and a long shelf life, such as air fresheners and hair sprays.

Compressed gas propellants like carbon dioxide (CO₂), nitrogen (N₂), and nitrous oxide (N₂O) remain gaseous under pressure. As the product is used, the pressure within the can decreases, leading to a less consistent spray pattern. However, they are preferred in specific applications—especially in the food and medical industries—because of their non-flammable and inert nature.

In general, liquefied gases offer better consistency and longevity in spray performance, while compressed gases offer environmental and safety benefits, albeit with limitations in pressure maintenance and formulation compatibility. The choice depends heavily on the intended application, with formulation specialists playing a key role in matching the right type of propellant to the desired product behaviour and regulatory requirements.

Low-GWP (Global Warming Potential) propellants such as HFO-1234ze are gaining traction due to environmental regulations and increasing awareness around climate impact. Global efforts to phase down high-GWP substances under agreements like the Kigali Amendment to the Montreal Protocol have pushed manufacturers to seek greener alternatives.

HFO-1234ze has a GWP of less than 1, compared to traditional HFCs like HFC-134a (GWP of 1,430). This makes it an environmentally superior option that aligns with EU F-gas regulations and the UK's sustainability goals. It is also non-flammable in most conditions, making it safer for users and easier to handle during storage and transportation.

Brands focused on eco-conscious consumers now view low-GWP propellants as essential to gaining market trust and regulatory approval. HFO-1234ze enables manufacturers to maintain product performance while significantly reducing climate impact. Hydrokem supports clients in integrating low-GWP propellants seamlessly into their existing or new product lines.

Yes, blending propellants is a common practice in aerosol formulation, enabling manufacturers to tailor pressure, spray characteristics, safety, and cost-efficiency. Blends may consist of hydrocarbons (e.g., butane, propane), DME, or a combination with more advanced options like HFO-1234ze to optimise performance.

For example, adding DME to a butane/propane blend can improve solubility and spray finesse in personal care products. Blending can also help balance flammability and reduce VOC content without compromising on user experience. However, not all combinations are compatible; chemical stability, packaging suitability, and regulatory approval must all be considered.

Hydrokem conducts extensive compatibility testing and pressure profiling to ensure custom propellant blends meet product expectations and legal standards. Our approach guarantees that your aerosol delivers consistent, safe, and effective results throughout its shelf life.

Yes, when used correctly and within regulated limits, DME and hydrocarbons are safe for cosmetic formulations. DME is widely accepted in personal care applications like hair sprays and deodorants due to its low toxicity and compatibility with alcohol-based systems. It is recognised as safe by regulatory bodies including the SCCS (Scientific Committee on Consumer Safety).

Hydrocarbons like isobutane, propane, and butane are similarly safe for use in cosmetics, provided they are refined to cosmetic-grade purity. They are widely used in aerosol deodorants, dry shampoos, and shaving foams. However, both DME and hydrocarbons are flammable, so safety precautions in packaging, labelling, and storage are essential.

At Hydrokem, we ensure compliance with ATEX and DSEAR regulations during formulation and filling, delivering safe and high-quality personal care aerosols. Our expert team also monitors global regulatory trends to help clients maintain product compliance across markets.

Hydrokem’s propellant selection process begins with a deep dive into the client’s goals—whether it’s product performance, spray behaviour, cost-efficiency, or sustainability. Our chemists consider several variables including solubility, compatibility with the formulation base, required spray pattern, and packaging limitations. Environmental factors like GWP and VOC limits are also factored into decision-making.

We conduct small-batch formulation testing with different propellant candidates to measure performance under controlled conditions. This process includes pressure profiling, fill-rate validation, and compatibility checks with valves and containers. Our end-to-end support ensures every aspect of the propellant formulation is optimised for safety, effectiveness, and compliance.

Clients also benefit from our regulatory expertise—Hydrokem monitors evolving legislation in the UK, EU, and globally to ensure our propellant recommendations meet all necessary standards. Our holistic approach reduces development risk and speeds up the route to market. Learn more about our full development support on the Lifecycle of a Private-Label Aerosol page.