My synthetic-leather bag or shoes are peeling and sticky. How long do they last? Can it be prevented?
This answer is a draft. It stays unpublished until legal review and source verification are complete.
A bag you bought only two or three years ago has a surface that has gone sticky and started to peel. This is "hydrolysis" (加水分解, kasui bunkai) of synthetic leather (合皮, gōhi). Synthetic leather is cheaper and lighter than real leather, but many people buy it without knowing it has a built-in lifespan, and the National Consumer Affairs Center of Japan receives complaints about it. Here is how it happens, and how to make it last a little longer.
Types of synthetic leather and their lifespans
| Material | Label | Character | Typical lifespan | How it fails |
|---|---|---|---|---|
| Polyurethane (PU) synthetic leather | "synthetic leather" (合成皮革), "polyurethane" (ポリウレタン) | Light, soft, close to real leather in feel. Most bags, shoes and sofas | 2–5 years (from manufacture) | Hydrolysis: sticky → cracks → peels. Progresses even unused |
| PVC (vinyl) synthetic leather | "synthetic leather" (合成皮革), "PVC" (塩化ビニル) | Firmer, cheap, water-resistant | 5–10 years | Hardens; plasticiser leaches out, leaving stickiness and cracks. Goes stiff in the cold |
| Artificial leather (microfibre type) | "artificial leather" (人工皮革) (Clarino, Ecsaine etc.) | Non-woven fabric impregnated with PU. Common in randoseru school satchels. Designed to resist hydrolysis | 6–10 years (randoseru usually carry a 6-year warranty) | Surface wear |
| Real leather | "cowhide" (牛革), "sheepskin" (羊革) etc. | Needs care, heavy, expensive | 10 years to decades | Drying out and cracking (preventable with care) |
Slowing hydrolysis
| Measure | Why |
|---|---|
| Store in a well-ventilated place | Humidity drives the reaction. Long spells in a plastic bag, sealed case, the back of a closet or a box are the worst conditions |
| Use it | Taking it out now and then so it gets air and dries usually makes it last longer than putting it away |
| Wipe off moisture | Wipe off rain, sweat and skin oils before storing. Leaving it wet speeds things up |
| Avoid heat and direct sun | Inside a car, by a window, near a heater all accelerate deterioration |
| Stuffing in storage | Newspaper to keep the shape (it also absorbs moisture). A dehumidifier pack nearby (but do not seal) |
| Dedicated protector | Protective spray for synthetic leather to guard the surface. Oils and creams made for real leather may not suit PU (stickiness) |
| When buying | Old stock (outlets, sales) may already have deteriorated before you buy. Choose PU labelled "hydrolysis-resistant", artificial leather or PVC |
- Once hydrolysis has started: there is no way back. Stickiness comes from inside, so wiping the surface does not help. Patching peeled areas (synthetic-leather repair sheets) is a cosmetic first-aid measure; it does not stop the process. Hydrolysis of PU shoe soles can be dealt with by replacing the sole (see our article on shoe repair).
- Shoes with PU soles: the midsoles of hiking boots and trainers are the classic case; the National Consumer Affairs Center has reports of soles disintegrating on the day someone put on five-year-old shoes. Press the sole of old shoes to check before wearing them.
- Household Goods Quality Labelling Act (家庭用品品質表示法, Japan's consumer labelling law): synthetic-leather bags and shoes must be labelled "synthetic leather" (合成皮革) or "artificial leather" (人工皮革); terms such as "leather" or "real-leather look" are regulated because they can be mistaken for real leather. Check the label when you buy.
- Price versus lifespan: a ¥5,000 synthetic bag replaced every 3 years, or a ¥30,000 real-leather bag used for 10 years? Daily use, long-term use → real leather; fashion pieces, occasional use, lightness first → synthetic.
- Disposal: in most municipalities it goes in burnable waste (once metal fittings are removed); large items are bulky waste (粗大ごみ, sodai gomi).
[Verify] The years quoted for hydrolysis and the lifespan of artificial leather are guidelines based on explanations from material manufacturers and the National Consumer Affairs Center. Check the labelling rules against the Miscellaneous Manufactured Goods Quality Labelling Regulations under the Household Goods Quality Labelling Act.
Misunderstanding 1｜Synthetic leather lasts longer if you keep it carefully put away
Hydrolysis continues even when unused, and sealed storage speeds it up through humidity. A ventilated spot and occasional use last longer.
Misunderstanding 2｜The stickiness is dirt, so wiping will fix it
It is internal deterioration coming to the surface, and wiping does not reverse it. Consider it the end of its life; for shoe soles, look at a sole replacement.
Misunderstanding 3｜Real-leather cream will make it last
Oils for real leather do not suit PU and can cause stickiness. Use a synthetic-leather protector, or just wipe with a dry cloth.
Misunderstanding 4｜Sale and outlet synthetic leather is the same quality
Stock that has sat since manufacture may already be deteriorating. Check the surface for stickiness and softness before you buy.
Misunderstanding 5｜Synthetic leather is fake leather and poor quality
Synthetic leather wins in many situations on weight, price and water resistance. The difference is a fixed lifespan. Choose by use.
---
Sources
- National Consumer Affairs Center of Japan, "Complaints about deterioration (hydrolysis) of synthetic-leather products (bags, shoes)" [合成皮革製品（バッグ・靴）の劣化（加水分解）に関する相談]
https://www.kokusen.go.jp/
- Consumer Affairs Agency, "Household Goods Quality Labelling Act: Miscellaneous Manufactured Goods Quality Labelling Regulations (material labelling for bags and shoes)" [家庭用品品質表示法：雑貨工業品品質表示規程]
https://www.caa.go.jp/policies/policy/representation/household_goods/guide/miscellaneous/
- Japan Leather and Leather Goods Industries Association, "Differences between leather, synthetic leather and artificial leather" [皮革と合成皮革・人工皮革の違い]
https://www.jlia.or.jp/
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
About this article
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
Follow the care label and the maker's instructions for any garment, shoe or bag. For expensive or sentimental items, ask a specialist cleaner or repairer.
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