Leather goods - the oldest handicraft, the road to sustainability

What drives us - in the series we'll look at the role of chemistry in supporting everyday life and improving the quality of life.

The oldest handicraft in the world has a turbulent history. Leather goods are still indispensable and controversial today. How are modern German chemicals and sustainable technologies revolutionizing leather products?

Environmental protection is between mainstream and luxury

As early as 5,000 years ago, Oz and his companions used the hides of slain animals to make belts, shoes, tents, bags, lighters, water bottles, and more. In other words, the tanning process is as old as human history. It is no exaggeration to say that it is the oldest industrial product, but it is now the subject of debate. The more popular a leather product is with consumers, the more controversial its manufacturing method becomes.

In the Middle Ages, tanned leather traders were banned from the town, a sneaky profession that dumped poisonous drainage into the river. Although most modern leather products are manufactured using modern technology and sustainable chemicals with an environmentally friendly nature, the leather industry is booming in some developing countries such as Bangladesh and Morocco. Thing of the past. In fact, the proportion of leather traders who do not meet environmental and health standards is estimated at less than 5%. The biggest problem is that consumers don't check that the bags and shoes they use are made sustainably. In addition, leather goods are no longer considered luxury goods. Leather products were originally designed for durability, as opposed to today's cheap leather products that are designed for every season trend.

The Food and Agriculture Organization of the United Nations (FAO) estimates that more than 50% of the leather produced globally is used in the fashion industry. Only about one-fifth is produced by tanning manufacturers in European countries, which require high environmental and health standards in addition to sustainable processes and chemicals. The result is a high-quality, durable leather product with careful manufacturing that justifies the "luxury" designation.

Assumption 1: "Leather is a fully recycled product"

yes. If leather products don't use animal skins, it's just garbage from the meat industry. In this sense, leather manufacturing is a successful example of recycling. Humane breeding and meat processing of animals are also important for high-quality leather. However, this is not the case in some meat processing facilities. These contradictions cannot be ignored, especially in developing countries that produce most of the leather used in the fashion industry. Stamps and certificates are designed to address these issues, but few leather products display them. Leading manufacturers such as Adidas, Nike, Lloyds and Deichmann are members of the Leather Working Group, which is committed to developing a sustainable leather industry, including the entire value chain process.

Assumption 2: "Manufacturing of leather goods is one of the most water-intensive industries"

Do not. The actual water consumption of leather products production is 16,458 liters per square meter. This seemingly large number includes the vast amounts of water used to water grasses that are vital to animal reproduction, as well as the water the animals need to grow. In fact, less water is required to make a leather product. Furthermore, the amount has dropped sharply over the past few years. Currently sustainable leather tanning uses only 60 to 200 liters of water per square meter, depending on the water recovery rate and procedure. The manufacturing process of vegetable tanned leather consumes a lot of water, but most of it is used for plant cultivation and tanning agent manufacturing. This is also why vegetable tanning is used in combination with other tanning methods.

Hypothesis 3: "Chrome-tanned leather is harmful to the environment and humans"

Do not. Tanning with inorganic salts such as chromium is the most important tanning technology at present, and more than 80% of raw leather is tanned by this method. With high-quality tanning agents and simple process control according to all criteria, chrome tanning does not have a negative impact on the environment compared to other tanning techniques. Chromium also has some advantages. Due to its molecular structure, chromium is the most effective tanning agent for tanning leather. Chrome tanning can be processed faster than other tanning processes, and the processed leather is extremely heat resistant, has twice the tear strength than vegetable tanned leather, and is lighter. The amount of tanning agents (eg chemicals) required in the retanning process is also significantly lower than in other tanning processes.

Assumption 4: "Only vegetable tanned leather is environmentally friendly"

Do not. There are pros and cons to the environmental and health impacts of any tanning process. Now, not only organic tanning but also vegetable tanning techniques are undergoing a renaissance. Leather products processed with tanning agents made from olive leaves, chestnuts and rhubarb root are popular. The rationale behind this ancient tanning technique is simple. All plants contain natural tannins to prevent spoilage while protecting predators. Vegetable tanning agents are based on tannins such as gallic acid polyphenols. If you use tannins from the leaves, they must be fresh so that the proteolysis does not go away. The bark collects tannins more efficiently, but in any case, the production of vegetable tanning agents requires a lot of water, and the tanning process takes a long time. While the vegetable tanning process takes months, the chrome tanning process only takes a few hours.

Assumption 5: "Artificial leather is more environmentally friendly and more humane than leather."

Do not. First of all, artificial leather is not leather by definition. This is because it is not an animal-derived material. Alternative materials are plastic or other natural materials. It is nearly impossible to reproduce many of leather's properties, such as ductility, toughness, durability and breathability, with alternative materials. Since artificial leather uses petroleum-based raw materials, it is not easy to biodegrade in nature, and chemicals such as plasticizers are required to express the leather. Even in this regard, artificial leather cannot achieve the original characteristics of leather.

Leather has unique properties. That's right, as humans and animals have evolved over thousands of years, leather is filled with all the elements that make skin a protective film. It is elastic, not easy to tear, and not easy to burn even when pulled hard. In addition, it has high thermal and thermal insulation and is more breathable than synthetic fibers. Leather shapes and colors can be customized more than ever. In other words, leather is a material that can be used for many purposes. "Leather is a long-term product. We want people who buy leather shoes to understand that it's not just for that season," says leather goods expert Dietrich Teckmeier. "Leather products can last for decades if properly cared for. Over the years, the texture may change, making them more attractive and even a better fit." Great knowledge of quality materials. Tegtmeier is responsible for developing LANXESS' leather and leather industry.

Perfectly recycled: an innovative, award-winning tanning process

Tectmeyer is committed to making the leather manufacturing process environmentally friendly and efficient by making the most of leather chemicals. His team won the German Innovation Award in the "Climate and Environment" category. In a joint project between Invite's laboratory and the leather tanning company Heller Leder in Nieder-Saxen, Germany, LANXESS has developed an environmentally friendly retanning agent using residues from the leather manufacturing process.

Dietrich Tegtmeier said: "The first pilot system of Heller Leder will allow tanneries to produce retanning agents on-site in a fully automatic and independent production line." I'll talk.

Shavings are long-standing residues in the leather industry. Only one-third of animal hides are actually processed as leather goods. Medium-sized leather suppliers produce about 1-2 tons of wood shavings per day. Thanks to the newly developed system, the wood shavings are instantly converted into a retanning agent and can be reused immediately during the tanning process. In other words, the leather is completely recycled. The in-house production of biodegradable retanning agents from renewable raw materials entails higher costs, which can be offset by the cost of transporting and handling the wood shavings.

The tanning process is the most important process in leather manufacturing, it guarantees the durability and flexibility of the leather. Tanning agents stabilize the collagen substrate contained in the leather, so the processed leather does not shrink or harden. But if it is not tanned, the raw hide will rot in a few days.


Leather Treatment: For smooth and firm leather

Today's leather industry (at least in Germany) needs sustainability. "Sustainable Leather Stewardship" is a sustainable and environmentally friendly process and product initiative launched by LANXESS seven years ago. LANXESS helps leather manufacturers produce leather in compliance with legal regulations and the quality standards of each brand.

Leather is not all the same. For example, coverings in the transportation industry (especially air transport) must be highly flame retardant. Leather is inherently flame retardant due to the chemical structure of collagen, and no flame retardant is required if the proper plasticizer is used.



High standards: Expect a lot from a perfect pair of shoes

Of all leather goods, shoes should be especially comfortable to wear. When it comes to stylish outdoor, consumers are primarily looking for high functionality and comfort. Outdoor options are waterproof, easy-care, and well-ventilated shoes. Most of these properties are already natural to leather, so unlike other outdoor products, you don't need to use perfluorinated compounds to get them. However, that doesn't mean you don't have to use chemicals at all. In order to respond to fashion trends, we have to meet various requirements such as gloss, smooth texture, rough texture, softness and so on. "The challenge was to create visually perfect harmony of leather from various leather materials," says Michael Franken. He is responsible for finishing in the manufacture and development of leather chemicals at Lussoloop. "Argentine hides look different from reddish-brown hides from the Sauerland region, and hides that are caught in barbed wire will still get scratched."

% of leather produced in industry

• 40-45% shoes
• ∽ 20% for cars
• ∽ 15% furniture
• ∽ 8% clothes
• ∽ 8% package
• ∽ 8% other

Few scratch-free leathers are expensive but require less rework. In contrast, many leathers go through many processes and require the use of 50-60 different leather chemicals and oils to meet consumer expectations. Therefore, an important objective of "sustainable leather management" is to optimize processes to meet consumer expectations and balance environmental responsibility. "Our goal is to generate tangible benefits in terms of reducing pollutants, neutralizing health risks and reducing carbon dioxide emissions," explains Dietrich Tegtmeier. "If we shouldn't collide environmental protection with profitability, we need to raise awareness of the value of leather, because leather goods are high-quality handicrafts."





To improve the sustainable structure of the leather industry, the LWG issues three certificates: Gold, Silver and Bronze. Gold is sent to model factories for environmental protection. Supply Chain Transparency is ranked from A to C, with A being awarded to suppliers who can trace all processes back to the slaughterhouse. This activity is voluntary. The LWG will not impose sanctions on members even if they do not make necessary improvements or advancements.