How DuPont Invented Neoprene Synthetic Rubber
A 1934 patent describing the chemical process to turn chlorobutadiene into a durable, oil-resistant synthetic rubber known as Neoprene.
Original patent title: “Process of polymerizing chlorobutadiene and resulting product”
A 1934 patent describing the chemical process to turn chlorobutadiene into a durable, oil-resistant synthetic rubber known as Neoprene. Granted to EI Du Pont de Nemours and Co in 1934 with 7 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
The patent outlines a chemical process for polymerizing chlorobutadiene, a liquid monomer, into a solid, rubber-like material. By controlling the reaction conditions, the process creates a synthetic elastomer that mimics the properties of natural rubber but offers superior resistance to oils, heat, and weathering. This invention allowed for the mass production of a stable, elastic substance that could be molded or shaped for industrial use.
The gap
What does this patent NOT cover?
- Does not cover the synthesis of natural rubber derived from latex trees.
- Does not cover other types of synthetic rubbers like styrene-butadiene (SBR).
- Does not cover the specific vulcanization additives used in finished consumer goods.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The invention successfully stabilized a highly reactive chemical (chlorobutadiene) that previously tended to spontaneously turn into a useless, hard, and brittle resin, turning it into a useful, elastic polymer instead.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Wetsuits for surfing and diving
Automotive fan belts and hoses
Protective industrial gloves
Laptop sleeves and cases
Why it matters
The bigger picture
This patent marks the birth of the synthetic rubber industry. It provided a critical alternative to natural rubber, which became a strategic necessity during World War II when supply chains for natural latex were severely disrupted.
Filed
May 14, 1931
Granted
July 24, 1934
Market context
Who's building on this
Companies in this space
DuPont remained the primary manufacturer of Neoprene for decades, though the patent eventually expired, allowing other chemical giants like Denka and Lanxess to enter the market.
Market impact
This patent created the entire synthetic elastomer market. It enabled the automotive and aerospace industries to rely on materials that could withstand harsh engine environments, fundamentally changing how machines are built.
Claim 1 — Plain English
What this patent covers
The patent outlines a chemical process for polymerizing chlorobutadiene, a liquid monomer, into a solid, rubber-like material. By controlling the reaction conditions, the process creates a synthetic elastomer that mimics the properties of natural rubber but offers superior resistance to oils, heat, and weathering. This invention allowed for the mass production of a stable, elastic substance that could be molded or shaped for industrial use.
The clever bit
The invention successfully stabilized a highly reactive chemical (chlorobutadiene) that previously tended to spontaneously turn into a useless, hard, and brittle resin, turning it into a useful, elastic polymer instead.
What it does not cover
- Does not cover the synthesis of natural rubber derived from latex trees.
- Does not cover other types of synthetic rubbers like styrene-butadiene (SBR).
- Does not cover the specific vulcanization additives used in finished consumer goods.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Limited data
Citation count
18/40
Early citations
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$12K – $37K
Midpoint $23K · expired or expiring · industry ×2.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
Concepts involved
Citations
Patent lineage
Cite this patent
Collins, A. M. (1934). How DuPont Invented Neoprene Synthetic Rubber (U.S. Patent No. 1,967,861). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/1967861/neoprene-synthetic-rubber
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How DuPont Invented Neoprene Synthetic Rubber cover?
A 1934 patent describing the chemical process to turn chlorobutadiene into a durable, oil-resistant synthetic rubber known as Neoprene.
Who owns patent US 1967861?
EI Du Pont de Nemours and Co owns this patent, granted in 1934.
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 1967861 cited by?
This patent has been cited by 7 later patents that build on its ideas.
What problem does this patent solve?
This patent marks the birth of the synthetic rubber industry. It provided a critical alternative to natural rubber, which became a strategic necessity during World War II when supply chains for natural latex were severely disrupted.
What does this patent NOT cover?
Does not cover the synthesis of natural rubber derived from latex trees.
Same assignee
More from EI Du Pont de Nemours and Co
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