Why is the “lifespan” of PU leather so short? Hydrolysis mechanism and countermeasures

I often hear people say, "PU leather has a short lifespan," or "It gets sticky and falls apart after a few years." In fact, the true nature of this "sudden deterioration" is due to the unique properties of polyurethane."Hydrolysis"This is a phenomenon.

In this article, we will explain the hydrolysis mechanism that affects the lifespan of PU leather.Stickiness, cracks, and peeling of the surfaceSigns of deterioration such asStorage and usage tips to extend the lifespan as much as possibleWe will explain everything in an easy-to-understand manner from an expert's perspective.

Not only for those who already have PU leather, but also for those who are planning to use it from now on.PU leather bags and accessoriesThe content is also useful for those considering purchasing.

Table of contents

COWMONO recommendation

If you want to experience the charm and practicality of PU leather,PU leather backpackis recommended. Our unique processing technology creates a texture that can be mistaken for genuine leather, while also being both practical and durable.

1. Is the “lifespan” of PU leather really short? Guidelines and misconceptions

The first thing to keep in mind is that it is not possible to simply say that PU leather has a lifespan of ◯ years. There are four main factors that affect lifespan:

  • polyurethaneQuality/formulation(Is it a cheap product or a high quality grade?)
  • Base material (fabric)Thickness/strength
  • everydayFrequency of use(Use every day or occasionally)
  • Storage environment(Humidity, temperature, presence of direct sunlight)

Generally, the lifespan of standard PU leather bags on the market isAbout 3 to 5 yearsAlthough it is often said that this is "just an average value".

  • Inexpensive mass-produced products: In some cases, hydrolysis begins in 2 to 3 years
  • High quality PU leather: in the right environment5-7 years, sometimes more than that

In other words, it does not mean that PU leather is a material that will quickly become useless.“How much can we delay hydrolysis?”is the point that determines lifespan.

After understanding hydrolysis,High quality PU leather products handled by COWMONOJust being conscious of material selection and storage can make a big difference in the actual lifespan.

2. Mechanism of “hydrolysis” that causes PU leather to deteriorate

What makes the surface of PU leather ispolyurethane resinIt is. Roughly speaking, polyurethane is a polymer (a type of plastic) made of the components ``isocyanate'' and ``polyol.''

In this molecule,Bonds such as “ester bonds” that easily react with wateris included, and thereMoisture (humidity), heat, ultraviolet raysIf stress continues to be applied, the molecules will gradually break. This ishydrolysisIt is.

2-1. Conditions where hydrolysis tends to occur

  • Hot and humid environment(closet, closet, window, etc.)
  • Places with large temperature changes(Rooms with high temperatures in the summer and prone to condensation in the winter, etc.)
  • direct sunlightor places exposed to heat from lighting or heaters for long periods of time.
  • Left in the same position for a long period of time (stored with zero ventilation)

When these conditions are met, the polyurethane molecules gradually break off.It loses flexibility and becomes sticky and powdery.It will look like this. This is the true reason why when you take out a PU leather bag that you haven't used in several years, it feels sticky to the touch or the surface falls off when you rub it with your fingers.

2-2. Why does the deterioration process differ from genuine leather?

Although it is called the same "leather",genuine leatherThe deterioration mechanism is completely different between PU leather and PU leather.

  • Genuine leather: When dry, oil and moisture are removed, causing hardening, cracking, and fading.
  • PU leather: Stickiness and peeling occur when the polyurethane molecules themselves break.

Genuine leather can be used for decades while enjoying "aging" depending on maintenance, but due to the chemical structure of PU leather,Materials that have a limited lifespan due to hydrolysisIt is. Instead,Affordability, lightness, and freedom of designIt has such advantages.

3. Signs of deterioration: Stickiness, cracks, and peeling of the surface

 

From here, we will introduce the "specific symptoms" that appear on PU leather that is undergoing advanced hydrolysis. If caught early, it is possible to slow down the progression to some extent.

3-1. Stickiness that sticks to your hands

Often the first sign issticky surfaceIt is.

  • When I touch it, my fingers feel slightly stuck together.
  • If stored on top of other items, the surfaces will stick to each other.
  • Tissues tend to stick

This is caused by the polyurethane molecules breaking.A state in which the surface is “melting”. At this point, even if there is no significant change in appearance, hydrolysis is progressing internally.

3-2. Fine cracks on the surface

As hydrolysis progresses further, this timefine cracks on the surfacecomes in.

  • Cracks appear in areas that are often bent (such as the base of the shoulder belt)
  • A whitish crack appears from the wrinkled peaks.

This is because the polyurethane layer loses its flexibility.Signs that you can't keep up with bending. At this stage, the deterioration in appearance becomes obvious.

3-3. “Surface peeling” that falls off slowly

As you go further, the surfaceIt flakes off like powder, or it peels off like a sheet.I will.

  • If you rub it with your fingers, something like black powder or scum will come out.
  • Small particles adhere to clothes from car seats and sofas
  • Only the shoulder part of the bag is extremely worn out.

Unfortunately, when it comes to this stage,Almost impossible to undoIt is. Now is the time to cover it to extend its life or consider replacing it.

4. How many years does PU leather last? Durability by grade

Here, we will organize the "lifespan of PU leather" by grade, just as a guide.

4-1. For general PU leather bags

  • Low price range (fast fashion, etc.)
    ・High frequency of use & high temperature and humidity → Stickiness and cracks tend to appear after 1 to 3 years
    - Approximately 3 to 4 years even under good conditions
  • High quality PU leather in medium to high price range
    ・If stored properlyAbout 5-7 yearsEasy to maintain at a sufficient practical level
    ・Do not use it often and store it in a well-ventilated place → There are cases where it can be used for more than that.

Of course there are individual differences, butIt is not uncommon for the lifespan of ``ultra-cheap PU leather from unknown sources'' and ``PU leather made from carefully selected materials'' to be about twice as long.。

Available at COWMONOCrazy Horse PU Leather BackpackThe type that combines microfiber base material and high-quality polyurethane is a durable grade that can be used for a long time with peace of mind.

4-2. Comparison with genuine leather and crazy horse leather

  • genuine leather：
    ・Depends on maintenanceover 10 yearsIt is also possible to use
    ・However, it is sensitive to water and mold, and requires a lot of care.
  • crazy horse leather：
    - Extremely durable, and the more you use it, the more the flavor will improve.
    ・For those who want to use it as a companion for a long time, as you can enjoy the scratches as a “taste”

For those who want to use their clothes for a long time and enjoy how they change over time, genuine leather and crazy horse leather are also options.
If you value ``lightness, price, and ease of handling,'' choose a high-qualityPU leather bagis the best balance.

5. Storage and daily care to extend life (reasons why high temperature, high humidity and direct sunlight are no good)

 

Now comes the practical part that will actually help you.Slow down the rate of hydrolysis as much as possibleTo that end, we have put together a list of measures you can take starting today.

5-1. Avoid high temperature and humidity (just don't create "humidity and high temperature")

The biggest enemy of hydrolysis is"Temperature + Humidity"This is a combo. Specifically:

  • I left it in a plastic bag in the back of the closet for several years.
  • Upper closet in summer (it tends to get hot near the ceiling)
  • Near a window or air conditioner vent

These are all places that are likely to fail.

ideal storage environmentHa,

  • A place with good ventilation and no direct sunlight
  • Room with humidity around 40-60%
  • Store in non-woven cloth bags instead of vinyl (improves breathability)

5-2. Avoid direct sunlight and strong light

UV light and heat accelerate the rate at which polyurethane molecules break down.

  • Car seat cover left by the window
  • Sofa placed by a sunny window
  • Bags left hanging in direct sunlight at the entrance

This kind of environment isHydrolysis + fadingIt is important to be careful as both can easily occur at the same time. Using curtains to soften the sun's rays or simply moving the area a little can help.

5-3. Lightly reset "sweat, sebum, and dirt" after use

If sweat and sebum stains remain on the surface for a long time, it will cause the surface coating to deteriorate.

  1. After use, wipe the entire surface with a soft dry cloth.
  2. If it gets wet in the rain, wipe it dry with a dry towel and then dry it in the shade in a well-ventilated place.
  3. If you are really concerned about dirt, use a diluted neutral detergent (very small amount) to wipe it clean, then wipe with water and then dry.

Even with this level of light care,"It deteriorates rapidly after a few years of being left alone."This worst-case scenario can be largely prevented.

5-4. Don't pack things too tightly and don't add strange folds.

Bags are separated from each other in closets and shelves.state of being crushedis also not allowed.

  • Cause of deformation and surface cracks
  • Hydrolysis damage is more likely to occur in areas that are locally stressed.

Make sure the bag has as much space as possible to stand on its own, and stuff it with paper or cloth to keep it in shape.
especially favoritePU leather BIG shoulder bagFor large bags such as , the filling during storage can have a direct impact on the lifespan of the bag.

6. Guidelines for material selection and replacement for those who want to make it last longer

After reading this far, some of you may be worried, "So should I give up on PU leather after using it for a few years?" So,Selecting materials from a long-term perspectiveI will also organize it.

6-1. PU leather is a material that can be enjoyed for 3 to 7 years

As long as it is hydrolyzed, PU leather is not a material that is meant to be used for 20 years. Instead,

  • affordable priceTherefore, it is easy to try out trendy designs.
  • Light and easy to handleTherefore, it is easy to use daily.
  • Water and dirt resistantTherefore, it is an excellent companion on rainy days.

There is a strength.
If you use it with the mindset of ``using it for 3 to 5 years and then buying a new one to suit your mood,'' you will find it easier to appreciate the cost performance of PU leather.

6-2. If you want to have a long-term relationship in units of 10 years, consider genuine leather and crazy horse leather.

On the contrary,

  • For business purposes, I want a companion that I can use for 10 years.
  • I want to enjoy aging (changes over time)

For those who say,Genuine leather productsor toughercrazy horse leather productsis suitable.

At COWMONO,

We have a lineup based on different materials, so we recommend choosing the material that suits you while considering the balance between "lifespan" and "price."

7. Summary: If you understand hydrolysis, PU leather will become your friend.

Finally, I will briefly summarize the main points of this article.

  • What determines the lifespan of PU leatherHydrolysis (a phenomenon in which polyurethane is decomposed by water and heat)
  • signs of deteriorationStickiness → cracks → peeling of the surfaceprogresses with
  • The estimated lifespan of general PU leather is3-5 years, if it is high quality PUAbout 5-7 yearsIt can also be used
  • High temperature and humidity and direct sunlightAvoiding this and doing light daily care can greatly change your lifespan.
  • If you value ``lightness, price, and ease of handling,'' PU leather is a good option, but if you want a ``friend for 10 years,'' then genuine leather and crazy horse leather are also candidates.

PU leather does have a ``lifespan due to hydrolysis'', but if you understand its properties and choose it properly, it is a very reliable material.
First, check the PU leather products you usually use,Storage location, humidity, sunlightPlease review it.

And when choosing a new PU leather product,COWMONO PU leather collectionWe recommend choosing from a shop that has a thorough explanation of the materials and specifications, such as . By being conscious of the balance between longevity and cost performance, you should be able to make a choice without regrets.

You can view COWMONO's leather products that offer high quality at low prices below.

Click here for Crazy Horse leather products

Click here for genuine leather products

We also sell high quality PU leather products that allow you to enjoy the texture of leather at a low price.

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Author information


Author name: Yama (Cowmono Owner)

Occupation: Slowth lab representative

Self-introduction: Engaged in sales and marketing for more than a quarter at domestic and overseas apparel companies. He has a deep knowledge of fashion, sports, outdoor activities, and subculture.