Incontinence Pad Construction and Performance | Adult Diaper Information Center Japan

English edition of a Japanese guide by Hiroshi Yagi. Japanese original: first published January 16, 2026; updated October 7, 2026. Read the Japanese original (Japanese).

Incontinence insert pads used with adult diapers consist of a topsheet, absorbent material, a waterproof backing and, in many cases, standing leak guards. When choosing a pad, consider its absorption speed, breathability and leak-prevention features as well as its absorbency. This illustrated guide explains the role of each part and how to read the absorbency information on Japanese packages.

How an incontinence pad is constructed

Cross-section of an incontinence insert pad: 1 topsheet, 2 absorbent material, 3 waterproof backing and 4 standing leak guards

1. Topsheet: feel against the skin and passage of liquid

2. Absorbent material: absorbency

3. Waterproof backing: breathable or non-breathable

4. Standing leak guards: barriers against leaks

Incontinence pad performance

Absorbency

Two incontinence insert pads with different amounts of absorbent material

Total absorbency and indicated absorbency in use are different measures. Total absorbency describes the pad when its absorbent area is fully saturated. Indicated absorbency in use is a guide to use. The Japanese source gives approximately 50–70% of total absorbency as a rough comparison, but this is not a universal conversion formula: products and measurement conditions differ. Some products for hospitals and care facilities list total absorbency; where available, use the manufacturer’s indicated absorbency in use instead. Absorption and liquid retention vary by product. Choose absorbency suited to the amount of urine, and check for surface wetness or leaks when sitting or lying down. Urine returning to the surface and contacting the skin can contribute to skin problems. Appropriate absorbency helps limit this return of liquid under body pressure.

NOTE

The examples discussed in the Japanese source include retail incontinence insert pads with indicated absorbency up to about 1,800 mL and products for hospitals and care facilities of about 2,000 mL. These are source examples, not verified limits for the whole current market.

Absorption speed

Comparison of how quickly two incontinence insert pads absorb liquid

Absorption speed varies by manufacturer and product. A manufacturer may offer faster-absorbing pads in a higher-tier range. The volume and strength of urine flow also vary from person to person. If a large amount of urine reaches the pad quickly, absorption may not keep up: urine can spread and leak. Consider absorption speed as well as absorbency, and choose a product suited to the person’s urination pattern. A faster-absorbing pad may help reduce leaks in these circumstances.

When absorption speed matters

• A large amount of urine at one time
• A strong urine flow

Waterproof backing

The waterproof backing prevents urine from passing through the back of the pad. Some backings allow water vapor to pass through; others do not.

Two incontinence insert pads stacked together, beside a seated person

CAUTION

Stacking pads with waterproof backings does not allow urine to pass directly through to the pad underneath. It can waste absorbent material and add bulk, which may restrict posture or movement and contribute to skin problems. This explanation concerns waterproof-backed pads.

Breathable and non-breathable pads

Comparison of vapor passing through a breathable pad and being blocked by a non-breathable pad

Both breathable and non-breathable pads are available. Humidity inside a diaper increases after urination. Breathable pads allow water vapor to escape, helping reduce trapped moisture. They may cost more than comparable non-breathable products. Japanese packages may also describe this as moisture permeability. Breathable pads are available at drugstores and supermarkets in Japan.

Demonstration comparing vapor passage through pads, with non-breathable material on the left and breathable material on the right — In this demonstration, the non-breathable pad on the left does not allow vapor through to the cup. Vapor passes through the breathable pad on the right to the cup.

Points to consider when choosing

Breathable: an option when trapped moisture and skin comfort are concerns.
Non-breathable: an option described in the source for people whose pads can be changed frequently. Breathability alone does not prevent skin problems.

Standing leak guards

Standing leak guards act as barriers that help keep urine or stool from flowing over the sides of a pad. A pad cannot absorb urine instantly. The guards temporarily hold the liquid while the absorbent core takes it in. Make sure the guards are raised when fitting the pad. Some pads do not have standing leak guards.

Blue test liquid held between raised standing leak guards while being absorbed — Make use of the standing leak guards.

Hiroshi Yagi

The standing leak guards hold the liquid briefly while the pad absorbs it.

Odor control

Many people worry about odor. These concerns can affect social activities or going out, so odor control is another consideration. Most of the products discussed address urine odor; some also address stool odor. Check the features stated for the individual product.

Some pads have odor-control features using ingredients such as silver ions (Ag⁺), catechins or activated carbon.

How to read package information

The Japan Hygiene Products Industry Association (JHPIA) publishes guidelines for labeling disposable diapers sold in Japan.

The stated volume per void

The Japanese source describes 150 mL per void as a commonly used package reference volume, with some products using 120 mL. Under the JHPIA guideline, manufacturers set this reference volume themselves. Check the volume stated on the specific package.

CAUTION

The actual amount of urine passed at one time varies from person to person.

Approximate number of voids absorbed

This label expresses indicated absorbency as an approximate number of voids. It is used on retail adult diaper packages in Japan. Read it together with the stated volume per void and the manufacturer’s measurement-method note.

NOTE

The JHPIA guideline’s void-count labeling provision does not apply to professional-use products for hospitals and care facilities or to light incontinence pads and liners.

Hiroshi Yagi

Use these points as a guide when choosing an adult diaper or pad.