In one of our earlier blog posts about vegan types of leather, we promised to take a separate look at PU leather. We do this because we do not use pure PU leather in our shoes, but it is also found in plant-based leather in a small proportion in the form of coatings. Anyone who consciously opts for vegan and fairly produced fashion for ethical and sustainable reasons will quickly come to the question of whether vegan leather with a PU content is still more sustainable than real leather.
In this blog article, we will take a closer look at this question and examine the advantages and disadvantages of this leather alternative. We will shed light on the manufacturing processes, analyze the ecological impact and ask ourselves how the synthetic PU alternative compares to conventional leather. We will also take a critical look at the emerging challenges and questions regarding the environmental impact of PU leather.
What is PU leather?
The manufacturing process of the alternative begins with the chemical synthesis of polyurethane, a versatile plastic. Here, different chemical compounds are combined with each other to create a polymer that mimics the desired properties of real leather. This polymer forms the basis for the coating, which later gives the characteristic leather appearance. Like all plastics, PU is also petroleum-based and for that reason alone is a not entirely uncritical material.
At the same time, plastics offer good conditions for many applications due to their versatile properties. In the case of vegan plant-based leather, PU is often used as a wafer-thin coating on the carrier material, e.g. Grape leather, applied. It is the combination of the PU coating and the carrier material that imitates the feel and appearance of real leather. Through a variety of embossing and dyeing techniques, PU leather can even get scars and textures that look confusingly similar to real leather.
Advantages of the synthetic PU variant
- Versatility in design: the material offers designers a wide range of design options
- Longevity & Resistance: PU leather is resistant to many everyday stresses, including some resistance to UV rays. Like all other things in our universe, except for love perhaps, it is also not indestructible. However, with careful care, it can look and work well over a long period of time.
- Simple care: As a rule, it is easier to care for than real leather. A damp cloth is often enough to remove stains, and it does not require further care products.
- Ethical aspect: One of the biggest advantages is that it does not require breeding and killing animals for its production. This makes it a preferred choice for anyone who has legitimate ethical concerns about the use of animal products.
- Consistent quality: While genuine leather can have natural flaws and variability, PU leather offers a more consistent look and feel.
Disadvantages of the leather alternative
- Petroleum-based: Most PU leather are petroleum-based. That means their production is based on a non-renewable resource whose mining and processing can have significant environmental impacts, from habitat destruction to greenhouse gas emissions.
- Chemicals in production: The production requires the use of chemicals that can be potentially harmful to the environment. This can result in pollution of waterways and soil if they are not used and treated properly.
- Dedegradability: PU leather is not biodegradable, which means that if it is not recycled, it can linger in landfills for centuries. This is in contrast to real leather, which also has a long degradation period, but is ultimately organic and therefore decomposes.
Juxtaposition of synthetic and genuine leather
We don't have to write a lot in terms of ethics, synthetic leather is clearly ahead here. With a view to the environmental impact, we want to first look at the climate aspects. The production of PU leather requires energy, which usually leads to CO2 emissions. If we compare the two alternatives with each other, the CO2 footprint of PU is significantly lower than that of real leather. An example: A 2017 study by CE Delft found that producing 1 kg of artificial leather (including PU) emits an average of 6.4 kg of CO2 equivalent, while 1 kg of cowhide produces 17.0 kg of CO2 equivalent. That is almost three times as much as with synthetic leather imitations and comes from the fact that much more resources are used for the production of animal leather over the entire life path due to the need for pasture and feed areas.
The gray area: bio-based PU leather
1. What is bio-based PU leather and how is it made?
Bio-based PU leather is a variant of polyurethane in which some of the petrochemical components are replaced by renewable bio-based components. These bio-based components can be derived from vegetable oils, such as. B. Castor oil, or other natural sources.
The manufacturing process is similar to that of conventional PU leather, but during polymerization, biobased polyols are used instead of or in addition to petrochemical polyols.
2. Environmental aspects:
- Reduced carbon footprint: The use of plant-based materials can help reduce the carbon footprint compared to petroleum-based materials.
- Reduced consumption of fossil fuels: The use of bio-based materials reduces dependence on petroleum and other fossil fuels.
- Potential biodegradability: Some bio-based materials can be biodegradable, but this depends on the exact composition.
3. Challenges and limits of biobased materials:
- Land use: The production of bio-based raw materials can compete with food production and thus lead to problems such as deforestation or other environmental effects.
- Water and pesticide consumption: Growing crops for bio-based materials can require significant water use and can lead to the application of pesticides and fertilizers, which in turn has environmental impacts.
- Cost: The production of bio-based PU leather can currently be even more expensive than that of the conventional variant, as the technology and infrastructure for bio-based materials are still in development.
- Performance and quality: Depending on the manufacturing process and blend, bio-based PU leather may vary in durability, appearance and feel, and may not always be on the same level as traditional PU leather.
Conclusion: is PU leather a real alternative?
First of all: Despite the obvious challenges, PU leather is not only a real, but also the better alternative compared to real leather. We come to the conclusion that leather has long since become equal in its functionality. More important, however, are the ethical and environmental aspects. From our point of view, the utilization and killing of other living beings to satisfy our needs is no longer acceptable today. At the same time, leather has been proven to have a worse CO2 footprint. However, if you already have leather goods that are still in good shape, you should also use them instead of buying something new directly. Because the most sustainable thing is to use things for as long as possible, once they are produced. That is why we pay particular attention to longevity in the production of our slippers.