# How Wallace Carothers Invented Nylon

> The foundational 1935 patent for synthetic linear polyamides, the chemical process that created the material we now call nylon.

- **Patent:** US 2130523
- **Original title:** Linear polyamides and their production
- **Owner:** EI Du Pont de Nemours and Co
- **Granted:** 1938
- **Status:** Public domain (expired)
- **Times cited:** 299
- **Field:** materials, chemical_engineering

## What it does

This patent describes the chemical synthesis of high-molecular-weight linear polyamides by heating diamines with dibasic acids. By controlling the polymerization process, the inventor created long-chain molecules that could be drawn into strong, flexible fibers. This process transformed simple chemical building blocks into a material capable of replacing natural silk in textiles and industrial applications.

## What it does NOT cover

- Does not cover non-linear or branched polyamide structures.
- Does not cover the specific manufacturing machinery used for spinning the fibers.
- Does not cover the use of polyamides in non-fiber applications like molded plastics.

## The clever bit

Carothers discovered that by maintaining a precise stoichiometric balance and removing water during heating, he could force the molecules to link into long, stable chains rather than short, useless clumps.

## Real-world examples

1. Nylon stockings
2. Parachute cords
3. Toothbrush bristles
4. Fishing line

## Why it matters

This patent marks the birth of the synthetic fiber industry. It allowed DuPont to mass-produce nylon, which became a critical material for everything from hosiery to parachutes during World War II.

## Frequently asked questions

### What does How Wallace Carothers Invented Nylon cover?

The foundational 1935 patent for synthetic linear polyamides, the chemical process that created the material we now call nylon.

### Who owns patent US 2130523?

EI Du Pont de Nemours and Co owns this patent, granted in 1938.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 2130523 cited by?

This patent has been cited by 299 later patents that build on its ideas.

### What problem does this patent solve?

This patent marks the birth of the synthetic fiber industry. It allowed DuPont to mass-produce nylon, which became a critical material for everything from hosiery to parachutes during World War II.

### What does this patent NOT cover?

Does not cover non-linear or branched polyamide structures.

**Full plain-English explainer:** https://patentbrief.org/patent/us/2130523/nylon-polyamide-carothers

**Original patent:** https://patents.google.com/patent/US2130523

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [How Stephanie Kwolek Invented the Liquid Crystal Solution for Kevlar](https://patentbrief.org/patent/us/3671542/kevlar-aramid-fiber) — A 1969 chemical discovery describing a specialized liquid mixture that allows for the creation of incredibly strong, high-performance synthetic fibers.
- [How Spandex Elastic Fibers Are Chemically Engineered](https://patentbrief.org/patent/us/2929804/spandex-lycra-elastic-fiber) — DuPont's 1960 patent for a stretchy, durable synthetic fiber made from segmented polymers, which became the foundation for modern Spandex.
- [The Molecular Structure of Kevlar High-Strength Fiber](https://patentbrief.org/patent/us/3819587/kevlar-aramid-fiber-kwolek) — Stephanie Kwolek's 1971 patent for DuPont describing the molecular alignment and manufacturing of extremely strong, lightweight synthetic aramid fibers, which became famous as Kevlar.
- [How DuPont Invented Neoprene Synthetic Rubber](https://patentbrief.org/patent/us/1967861/neoprene-synthetic-rubber) — A 1934 patent describing the chemical process to turn chlorobutadiene into a durable, oil-resistant synthetic rubber known as Neoprene.
- [How Leo Baekeland Invented Bakelite, the First Synthetic Plastic](https://patentbrief.org/patent/us/942699/bakelite-synthetic-plastic) — A 1909 patent for creating a durable, heat-resistant material by reacting phenol and formaldehyde, marking the birth of the modern plastics industry.