# How to Make Silly Putty Using Silicone and Zinc > A 1944 chemical process for turning liquid silicone oil into a bouncy, stretchable, putty-like material by adding boron compounds and zinc hydroxide. - **Patent:** US 2541851 - **Original title:** Process for making puttylike elastic plastic, siloxane derivative composition containing zinc hydroxide - **Owner:** General Electric Co - **Granted:** 1951 - **Status:** Public domain (expired) - **Times cited:** 80 - **Field:** materials, consumer_electronics, mechanical ## What it does The patent describes a three-step chemical process to create a unique elastic material. First, you heat liquid dimethylsiloxane with a boron-based catalyst, such as boric acid or borax, until it transforms into a solid, rubbery substance. Second, you incorporate a finely divided inorganic filler along with 12 percent zinc hydroxide by weight. Finally, you knead this mixture until it reaches a specific consistency that is both putty-like and elastic, allowing it to bounce like a ball or stretch like taffy. ## What it does NOT cover - Does not cover the use of non-silicone base polymers for creating elastic putty. - Does not cover processes that exclude the specific addition of zinc hydroxide as a hardening or stabilizing agent. - Does not cover liquid silicone compositions that have not been processed into a solid, elastic state via boron heating. ## The clever bit The innovation lies in using zinc hydroxide as a specific additive to stabilize the silicone-boron matrix, preventing the material from becoming too sticky or losing its shape over time. ## Real-world examples 1. Silly Putty 2. Bouncing putty toys 3. Early silicone-based industrial sealants ## Why it matters This patent captures the early development of silicone-based elastomers, which became the foundation for materials like Silly Putty. It represents a significant moment in polymer science where chemists learned to manipulate silicone chains to create materials with strange, non-Newtonian physical properties. ## Frequently asked questions ### What does How to Make Silly Putty Using Silicone and Zinc cover? A 1944 chemical process for turning liquid silicone oil into a bouncy, stretchable, putty-like material by adding boron compounds and zinc hydroxide. ### Who owns patent US 2541851? General Electric Co owns this patent, granted in 1951. ### 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 2541851 cited by? This patent has been cited by 80 later patents that build on its ideas. ### What problem does this patent solve? This patent captures the early development of silicone-based elastomers, which became the foundation for materials like Silly Putty. It represents a significant moment in polymer science where chemists learned to manipulate silicone chains to create materials with strange, non-Newtonian physical properties. ### What does this patent NOT cover? Does not cover the use of non-silicone base polymers for creating elastic putty. **Full plain-English explainer:** https://patentbrief.org/patent/us/2541851/silly-putty-bouncing-silicone **Original patent:** https://patents.google.com/patent/US2541851 --- _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 Play-Doh Was Invented](https://patentbrief.org/patent/us/3167440/play-doh-modeling-compound) — 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. - [Sticky, Tiny Plastic Balls Made from Acrylates](https://patentbrief.org/patent/us/3691140/post-it-repositionable-adhesive) — This 1972 patent describes how to make tiny, sticky, and durable plastic balls (microspheres) using a specific mix of acrylate chemicals and a special water-based process. - [How Soft Contact Lenses Were Invented Using Hydrogels](https://patentbrief.org/patent/us/3220960/soft-contact-lens-hydrogel) — This patent describes the chemical recipe for soft, water-absorbing plastic materials that form the basis of modern soft contact lenses. - [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. - [Making Strong, Porous PTFE: The Gore-Tex Process](https://patentbrief.org/patent/us/3953566/gore-tex-expanded-ptfe) — This patent describes a specific process for rapidly stretching a highly crystalline form of PTFE plastic to create a strong, porous material with a unique internal structure, forming the basis for products like Gore-Tex.