Plastens historie: fra Bakelit til moderne svejsbar termoplast
How the first synthetic material was invented and how plastic conquered construction
Plastic is one of the youngest materials a craftsman works with. Where stone, wood and metal have been used for thousands of years, synthetic plastics are barely a hundred and fifty years old. Yet in that short time it has become indispensable in pipes, tanks, cables, insulation and thousands of other things. The history of plastic is the story of how chemists learned to build completely new materials from molecules — and how the profession then had to learn to work safely with them.
§Before synthetic plastic: nature's own polymers
Længe før den syntetiske plast brugte man naturlige materialer, der mindede om den. Skildpaddeskjold, horn, shellak fra lakskjoldlus og naturgummi blev formet ved varme og brugt til alt fra knapper og kamme til isolering af elektriske ledninger. Disse materialer var de første formbare stoffer, men de var dyre, sårbare og afhængige af, hvad naturen kunne levere. Behovet for noget bedre voksede, efterhånden som industrien — og især den nye elektriske industri — krævede materialer, der kunne isolere og formes i store mængder.
§Bakelite: the World's First Fully Synthetic Plastic
The decisive breakthrough came in the early 1900s. In 1907 the Belgian-American chemist Leo Baekeland in New York produced the first fully synthetic material — a thermosetting plastic of phenol and formaldehyde which he called Bakelite. It was also Baekeland who gave the material class the name 'plastics'. Bakelite was a true synthetic substance not just an improved natural material and its excellent insulating properties quickly made it the standard material in contacts sockets and parts for the growing electrical industry.
§Inter-war period: the modern plastic types arrive
After World War I, chemistry exploded, and the plastic types we know today were born in droves. PVC (polyvinyl chloride) was known as a molecule as early as the 1800s, but was not commercially produced until the late 1920s. Polystyrene came into industrial production in the 1930s, and polyethylene — today one of the most widely used plastic types for pipes and films — was discovered in the same period. These were thermoplastics: they soften when heated and can be reshaped again and again, opening an entirely new world of possibilities for molding, extrusion, and later welding.
Mass production really took off in the 1940s and 1950s. World War II pushed development forward because plastic could replace materials that were scarce and after the war new cheap plastic types flowed into everyday life and construction. Also epoxy resin — a thermosetting plastic with strong adhesive properties — was developed in this period and found its way into adhesives casting flooring and paint.
| Period | What happened |
|---|---|
| Før 1900 | Natural polymers: shellac, horn, natural rubber for buttons and insulation |
| 1907 | Leo Baekeland invents Bakelite — the world's first fully synthetic plastic (phenolic plastic) |
| 1920'erne | PVC goes into commercial production |
| 1930'erne | Polystyrene and polyethylene arrive; epoxy is developed in the same era |
| 1940'erne-50'erne | Mass production of plastic; the war accelerates development |
| Second half of the 1900s | Plastic pipes are combustible and melt; at a penetration an intumescent collar is used, which expands and closes the opening when the pipe melts. |
| Modern times | Lovkrav om uddannelse til epoxy og isocyanater; kodenummer og sikkerhedsdatablade |
| Today | Weldable thermoplastic as backbone in pipes and tanks; chemical work environment controlled |
§Plastic conquers construction
In the second half of the 1900s plastic became a building material on par with metal. Plastic pipes of PE PP and PVC replaced in many cases metal and clay pipes because they were light rust-free chemical-resistant and cheap to lay. This created a new craft: joining plastic tight and strong. First it was glued and muffed but gradually the welding methods matured — hot air welding mirror welding extruder and later electrofusion welding — so plastic joints could become as reliable as the pipes they replaced.
§The shadow side: when the chemical health risk was discovered
Initially plastic and the associated chemicals were used relatively unconcerned. But it gradually turned out that several of the reactive products — especially epoxy and isocyanates (including polyurethane) — could cause serious and lasting allergies and respiratory problems among those who worked with them daily. This led to a gradual tightening of occupational health rules: requirements for special training before you can work professionally with epoxy and isocyanates the code number system on paints and glues and requirements for safety datasheets and hazard labelling. From being a new wonder material plastic and its chemicals also became something you had to protect yourself against.
§Plastic granulate is injection moulded
Today plastic is a mature profession with two legs. One is quality: knowing the many plastic types choosing the right one for the task and making tight strong welds that can be documented and pressure tested. The other is safety: reading the safety datasheet and code number choosing the right protective equipment ensuring extraction and having the legally required training before touching epoxy and isocyanates. The short history — from Baekeland's laboratory to today's piping — is the story of a material that went from curiosity to everyday and a profession that had to learn both to exploit and respect it.
“Plastic is the youngest of craft materials — and the only one built from scratch in a laboratory rather than taken from nature.”