Plastics in action: The Invention of Rainwear
26.11.2025
18,000 invisible guards per square centimeter
It's familiar: it's drizzling in the morning, you grab your rain jacket or raincoat. After eight hours of commuting, meetings and errands, you're still dry - and not just on the outside. No clammy skin, no sweating. But how exactly does this actually work?
The answer lies in the textile coating or membrane: a Gore-Tex membrane in a modern rain jacket has around 1.3 billion microscopically small pores per square centimeter. Each one is 20,000 times smaller than a raindrop, but 700 times larger than a water vapor molecule. This is not magic - this is material science. And there is a 200-year history of chemistry behind it, in which foul-smelling tar was turned into high-tech textiles.
The man who clamped cotton between rubber
Scotland, early 19th century. The Scottish physician and chemist Sir James Syme experimented with dye production and obtained a by-product from coal gasification: Coal Tar Naphtha, a solvent that does not mix with water. This substance aroused the interest of Charles Macintosh, a chemist from Glasgow. He saw the potential: rubber can be dissolved in Coal Tar Naphtha - and this in turn can be applied to cotton fabric. Combined with two layers of fabric, the result was a waterproof material - the basis for the first functional raincoat. Macintosh patented his method in 1823.
The price? Today we would call it a designer piece. Which is surprising when you consider the smell. Because it was pungently chemical and tar-like. Not for sensitive noses. Did it detract from its popularity? No, the demand was enormous - especially among the British army.
It was the American Charles Goodyear who solved the odour problem: by treating natural rubber with sulphur - known as vulcanization - he made it suitable for everyday use. Elastic, durable, and you could wear it without passers-by changing sides of the street. Today, we tend to think of car tires when we hear the name Goodyear. You can read here in K-Mag why vulcanization was also an accidental find.
From fishing raincoat to invisible membrane
Fast forward to the 1970s: the bright yellow, so-called “Friesennerz” becomes a cult item in northern Germany. PVC on polyester - practical, robust, highly visible. Not only fishermen wore them, but also city dwellers and children. The problem? After an hour of cycling, you're swimming in your own juice. The simple logic behind it: What doesn't let rain through from the outside doesn't let sweat out from the inside either.
The solution came from space travel. Well, almost. In 1969, a chemist named Robert W. Gore (that's right, the guy from Gore-Tex) accidentally developed a material that changed everything: expanded polytetrafluoroethylene (ePTFE). He stretched PTFE so much that a structure with billions of tiny pores was created.
The result? A membrane that doesn't let water through, but lets water vapor (i.e. sweat) out. For the first time, it stayed nice and dry under a rain jacket or coat.
How a jacket breathes (without lungs)
Modern rain jackets are sandwich constructions with several layers:
- Outer fabric: usually polyamide (nylon) or polyester - robust and lightweight. A DWR (“Durable Water Repellent”) coating sits on top, which allows water to roll off like on a lotus flower.
- The membrane: the centerpiece. Polyurethane (PU), thermoplastic polyurethane (TPU) or the aforementioned ePFTE with microscopic pores. The choice today is huge.
- Inner lining: Protects the membrane and transports moisture to the outside. Often made of polyester or nylon, sometimes also cotton.
A high-quality waterproof Gore-Tex jacket can withstand a water pressure of 28,000 mm water column (this corresponds to the pressure of a 28 m high water column and is a measure of the waterproofness of a material). For comparison: a cloudburst produces about 2,000 mm. You could theoretically stack 14 downpours on top of each other.
15 PET bottles you have drunk
“Is it sustainable?” - The question hangs over the entire outdoor industry like a storm cloud. The honest answer: it's getting better, but it remains complicated.
The good news:
- Many manufacturers now use recycled polyester. Your new jacket? It might be made from 15 old water bottles.
- PFC-free impregnations are on the rise. The old perfluorinated and polyfluorinated chemicals - practically indestructible and bioaccumulative - are slowly disappearing from products. Look out for the label: “PFOA-free” or “PFC-free”
- Quality pays off: A good rain jacket lasts 10+ years. This is circular economy in practice.
The bad news:
- Microplastic fibers dissolve during washing. This can amount to hundreds of thousands of particles per wash cycle, which end up in the wastewater.
- Recycling remains difficult: multi-layer composites can hardly be separated by type.
What you can do: Use wash bags against microplastics (filter up to 90% of the fibers), wash less often (airing is often enough), and pay attention to repairability when buying.
The rain jacket of the future
Work is already underway in laboratories around the world:
- Self-cleaning surfaces based on beetle armor that repel dirt and water in equal measure
- Adaptive textiles that self-regulate their breathability depending on temperature and humidity
Research is focused on developing membranes from renewable raw materials that offer the same performance as materials already in use.
200 years of research on your skin
Next time you cycle to work in the fall rain and arrive dry - think about this for a moment: a piece of scientific history lies on your shoulders.
Synthetic products have revolutionized weather protection. Not despite, but because of their unique properties. The challenge for the next 200 years? To combine this functionality with ecological responsibility.
→ The combination of membrane (PU/TPU with micropores), DWR coating on the outside and sealed seams. Water column values from 10,000 mm are considered waterproof.
→ Yes, the DWR layer wears off. You will notice it when water no longer beads up and the fabric becomes soaked. Solution: Re-impregnate (spray or wash-in).
→ Outer: Polyamide (nylon) or polyester. Membrane: polyurethane (PU), TPU or ePTFE. Zippers: often polyoxymethylene (POM). Practically every component is a polymer.
→ Measured in MVTR (Moisture Vapor Transmission Rate): How many grams of water vapor per square meter get through in 24 hours. Good jackets manage 10,000+ g/m²/24h.
→ Absolutely! Seal holes with patches, renew waterproofing. Many manufacturers offer repair services. A new jacket usually costs considerably more.
→ It depends: Recycled material, durability, PFC-free and repairability are plus points. Microplastics and difficult end-of-life recycling remain problems. The best jacket is the one you wear for 10 years.
Fancy tinkering with the rain jacket of tomorrow yourself?
Textile technology, polymer chemistry, materials science - the plastics industry is looking for creative minds who can combine functionality and sustainability. At the K trade fair, you can find out about training and study opportunities and talk to professionals from the industry. Click here for the Young Talents of the K trade fair!
Who knows - maybe you will develop the first completely compostable high-tech membrane. The industry is waiting for you.
More exciting reading recommendations in K-Mag:
Author: Simone Ernst | K-Mag
Simone Ernst has been writing for various industry magazines for eighteen years and has been part of the K-Mag editorial team since 2024. She is particularly interested in topics such as plastics recycling, sustainability in the plastics industry and career paths in the plastics and rubber industry.
This article was created with additional AI tools.
At a glance
The history of the raincoat is a journey through 200 years of material research: from rubberized fabrics to high-tech textiles with microporous synthetic membranes such as Gore-Tex. Modern rain jackets keep you dry and are breathable. Sustainability is becoming more of a focus - but recycling remains a challenge.