Toner Pads and Pre-Soaked Formats: Manufacturing Notes
Pre-soaked pads have moved from a niche format to a significant category, particularly for exfoliating acids, toners and cleansing. The product is simple in concept and demanding in execution, because the pad has to retain its liquid for the full shelf life, release it evenly on first use, and remain microbiologically sound in a container that is opened daily. Three variables decide all of it.
The Substrate
The pad material determines how much liquid it holds, how it feels, whether it sheds fibres and how wet it feels when the customer takes it out.
- Cotton. Soft, familiar and good at releasing liquid. It can shed fibres over the shelf life, particularly if the liquid is acidic, and cotton is the most expensive common substrate.
- Viscose or a cotton viscose blend. The standard for most commercial products. Good absorbency, clean edges and lower cost than pure cotton.
- Non-woven polyester and blends. Durable and dimensionally stable, with a slightly synthetic feel. Used where the liquid is aggressive or where dimensional stability in the jar matters most.
- Embossed and textured pads. One side smooth for wiping, one side textured for light mechanical exfoliation. The textured side changes the liquid release and is worth specifying deliberately rather than as a decorative feature.
- Hydrogel and gel pads. Not a fabric, but a cast gel. A different process and a different cost level, used for premium treatment pads.
Pad dimensions matter more than expected. A 60 to 70 millimetre round pad is the common size. Thickness controls the liquid holding capacity, and a thicker pad holds more but feels heavier and costs more. The customer's perception of value is closely tied to how wet the pad feels, which makes thickness a commercial as well as a technical decision.
Saturation: The Number That Decides Everything
Saturation is the mass of liquid held per pad, usually expressed as a multiple of the dry pad weight. A pad whose dry weight is one gram with a saturation ratio of three holds three grams of liquid.
The target saturation is a compromise. Too low and the pad feels dry, the customer uses two, and consumption doubles. Too high and the liquid pools in the jar, the pads at the bottom become soaked while those at the top dry out, and the packaging may leak.
Practical targets vary by product type. A hydrating toner pad typically sits at a ratio of 2.5 to 4 times dry weight. An exfoliating acid pad is usually higher, because the customer expects a thoroughly wet pad. The exact figure has to be validated by a release test, not assumed: take pads from the top, the middle and the bottom of the filled jar after storage and measure the liquid content of each.
The Jar and Evaporation
This is where most pre-soaked products fail. A jar of pads holds a substantial volume of liquid in a container that is opened once or twice a day, and every opening allows moisture to escape.
- The seal is the critical component. A jar with a simple screw lid and no liner will lose measurable weight over months. A lid with a compatible liner, or a flip-top with a silicone gasket plug, retains far more.
- The inner seal and the flip lid. Many pad jars use a flip top with a hinged lid and an internal plug. The plug has to compress against the rim to seal, and it must still do so after a year of opening.
- Headspace. A jar filled to the brim has less air to exchange and loses less moisture than a half filled jar. It also prevents the pads from moving and compressing in transit.
- Orientation. Pads should be stacked so the liquid distributes evenly by gravity over time. A jar stored upright will have wetter pads at the bottom, which is normal and acceptable if the saturation margin covers it.
The stability test for this format has to include weight loss at accelerated conditions and a pad by pad saturation check at the end, not just an assay on the pooled liquid.
Preservation and the Acid Problem
A jar of pads is a high contamination product. The customer's fingers enter the jar, often immediately after touching their face, and the pad carries skin contact material back into the container. The preservative system has to account for that, and the standard challenge test on the liquid alone understates the risk.
Where the product is an exfoliating acid pad, the formula pH is low, which restricts the preservative palette to acid tolerant options and reduces the efficacy of several common systems. Combining an acid active with a system that passes the challenge test at pH 3.5 is the central technical difficulty of the category, and it frequently forces a compromise on the acid strength.
A practical mitigation is to run the challenge test in the actual jar with pads present, not on the liquid in a laboratory bottle. The pad itself can either absorb preservative or provide a surface that supports growth, and both effects are invisible in a liquid only test.
Filling the Pads
Two production routes exist. In the first, the pads are stacked into the jar and the liquid is dosed into the jar, relying on capillary action to distribute it. This is simple and works well for thin pads and low viscosity liquids, and it requires a period of equilibration after filling before the product is packed.
In the second, the pads are saturated in a bath and then stacked. This gives more even saturation immediately, uses more liquid and requires careful handling to avoid over-saturating and dripping during stacking. It also raises microbiological risk because the pads are handled wet.
Either route needs an equilibration period of at least several hours, often a day, before the weight and the saturation distribution can be verified. A jar checked immediately after filling will not reflect the distribution the customer will find.
Claims and Positioning
A pad is a convenience format and the claims should match. For an acid pad: exfoliates, smooths the look of skin texture, helps skin appear brighter. For a hydrating pad: hydrates, refreshes, preps the skin. Claims about removing blackheads, treating pores or reducing blemishes are the ones that create regulatory exposure, and they appear constantly in this category.
One practical note on labelling. Because the liquid is a cosmetic and the pad is a delivery device, the pack should state the number of pads and the net content of the liquid, and both have to be accurate. Net content rules apply to the liquid, not to the pad, and the pad weight should not be counted towards the declared quantity.
Pad Products With the Saturation Validated
OEM COSMETICS ODM produces toner pads, exfoliating pads, cleansing pads and treatment pads on ISO 22716 and GMP certified lines, with substrate testing, saturation measurement pad by pad after storage, jar seal and weight loss validation and challenge testing performed in the pack with pads present. Send us the format and the target pH and we will confirm what the preservation system can hold.
Talk to our team: WhatsApp +86 18709713948 · Email adon@oemcosmeticsodm.com · Website www.oemcosmeticsodm.com