# How Play-Doh Was Invented

> The original 1965 patent for the soft, non-toxic modeling compound known as Play-Doh, detailing a specific mixture of flour, water, salt, and kerosene.

- **Patent:** US 3167440
- **Original title:** Plastic modeling composition of a soft, pliable working consistency
- **Owner:** Rainbow Crafts Inc
- **Granted:** 1965
- **Status:** Public domain (expired)
- **Times cited:** 29
- **Field:** consumer_electronics

## What it does

The patent defines a specific chemical mixture that creates a soft, pliable, and non-sticky modeling clay. The composition relies on a precise ratio of grain flour, water, a water-soluble inorganic chlorine salt, and a small amount of kerosene. This combination allows the material to remain lump-free and re-workable over long periods without drying out or becoming toxic to children. By balancing these ingredients, the inventors created a substance that holds its shape when molded but remains soft enough for easy manipulation.

## What it does NOT cover

- Does not cover modeling compounds that exclude the specific range of kerosene as a lubricant.
- Does not cover clay-based modeling materials that do not use grain flour as the primary base.
- Does not cover mixtures that omit the water-soluble inorganic chlorine salt.

## The clever bit

The inclusion of kerosene acts as a subtle lubricant and preservative, preventing the flour-and-water mixture from becoming sticky or developing mold while maintaining a velvety texture.

## Real-world examples

1. Play-Doh modeling compound

## Why it matters

This patent protected the formula for Play-Doh, which became one of the most successful children's toys in history. It transformed a product originally intended for cleaning wallpaper into a global cultural staple for creative play.

## Frequently asked questions

### What does How Play-Doh Was Invented cover?

The original 1965 patent for the soft, non-toxic modeling compound known as Play-Doh, detailing a specific mixture of flour, water, salt, and kerosene.

### Who owns patent US 3167440?

Rainbow Crafts Inc owns this patent, granted in 1965.

### 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 3167440 cited by?

This patent has been cited by 29 later patents that build on its ideas.

### What problem does this patent solve?

This patent protected the formula for Play-Doh, which became one of the most successful children's toys in history. It transformed a product originally intended for cleaning wallpaper into a global cultural staple for creative play.

### What does this patent NOT cover?

Does not cover modeling compounds that exclude the specific range of kerosene as a lubricant.

**Full plain-English explainer:** https://patentbrief.org/patent/us/3167440/play-doh-modeling-compound

**Original patent:** https://patents.google.com/patent/US3167440

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


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