Je travaille sur la chronologie de la découverte du nylon et j'ai besoin de confirmer une information. Quand a été produit le premier nylon 66 ?
DuPont and the invention of nylon

Researchers at DuPont began developing cellulose-based fibers, culminating in the synthetic fiber rayon. DuPont's experience with rayon was an important precursor to its development and marketing of nylon.

DuPont's invention of nylon spanned an eleven-year period, ranging from the initial research program in polymers in 1927 to its announcement in 1938, shortly before the opening of the 1939 New York World's Fair. The project grew from a new organizational structure at DuPont, suggested by Charles Stine in 1927, in which the chemical department would be composed of several small research teams that would focus on "pioneering research" in chemistry and would "lead to practical applications". Harvard instructor Wallace Hume Carothers was hired to direct the polymer research group. Initially he was allowed to focus on pure research, building on and testing the theories of German chemist Hermann Staudinger. He was very successful, as research he undertook greatly improved the knowledge of polymers and contributed to the science.

Nylon was the first commercially successful synthetic thermoplastic polymer. DuPont began its research project in 1927. The first nylon, nylon 66, was synthesized on February 28, 1935, by Wallace Hume Carothers at DuPont's research facility at the DuPont Experimental Station. In response to Carothers' work, Paul Schlack at IG Farben developed nylon 6, a different molecule based on caprolactam, on January 29, 1938.

In the spring of 1930, Carothers and his team had already synthesized two new polymers. One was neoprene, a synthetic rubber greatly used during World War II. The other was a white elastic but strong paste that would later become nylon. After these discoveries, Carothers' team was made to shift its research from a more pure research approach investigating general polymerization to a more practically focused goal of finding "one chemical combination that would lend itself to industrial applications".

It was not until the beginning of 1935 that a polymer called "polymer 6-6" was finally produced. Carothers' coworker, Washington University alumnus Julian W. Hill had used a cold drawing method to produce a polyester in 1930. This cold drawing method was later used by Carothers in 1935 to fully develop nylon. The first example of nylon (nylon 6.6) was produced on February 28, 1935, at DuPont's research facility at the DuPont Experimental Station. It had all the desired properties of elasticity and strength. However, it also required a complex manufacturing process that would become the basis of industrial production in the future. DuPont obtained a patent for the polymer in September 1938, and quickly achieved a monopoly of the fiber. Carothers died 16 months before the announcement of nylon, therefore he was never able to see his success.

Nylon was first used commercially in a nylon- bristled toothbrush in 1938, followed more famously in women's stockings or "nylons" which were shown at the 1939 New York World's Fair and first sold commercially in 1940, whereupon they became an instant commercial success with 64 million pairs sold during their first year on the market. During World War II, almost all nylon production was diverted to the military for use in parachutes and parachute cord. Wartime uses of nylon and other plastics greatly increased the market for the new materials.

The production of nylon required interdepartmental collaboration between three departments at DuPont: the Department of Chemical Research, the Ammonia Department, and the Department of Rayon. Some of the key ingredients of nylon had to be produced using high pressure chemistry, the main area of expertise of the Ammonia Department. Nylon was considered a "godsend to the Ammonia Department", which had been in financial difficulties. The reactants of nylon soon constituted half of the Ammonia Department's sales and helped them come out of the period of the Great Depression by creating jobs and revenue at DuPont.

DuPont's nylon project demonstrated the importance of chemical engineering in industry, helped create jobs, and furthered the advancement of chemical engineering techniques. In fact, it developed a chemical plant that provided 1800 jobs and used the latest technologies of the time, which are still used as a model for chemical plants today. The ability to acquire a large number of chemists and engineers quickly was a huge contribution to the success of DuPont's nylon project. The first nylon plant was located at Seaford, Delaware, beginning commercial production on December 15, 1939. On October 26, 1995, the Seaford plant was designated a National Historic Chemical Landmark by the American Chemical Society.
Utilisations

Le nylon a été utilisé commercialement pour la première fois en 1938 dans une brosse à dents à poils en nylon, suivi, plus célèbre, par des bas pour femmes, ou « nylons », qui ont été présentés à l'Exposition universelle de New York de 1939 et vendus commercialement pour la première fois en 1940. Son utilisation a considérablement augmenté pendant la Seconde Guerre mondiale, lorsque le besoin de tissus a explosé.
### Query ###
Je travaille sur la chronologie de la découverte du nylon et j'ai besoin de confirmer une information. Quand a été produit le premier nylon 66 ?

### Main Text ###
DuPont and the invention of nylon

Researchers at DuPont began developing cellulose-based fibers, culminating in the synthetic fiber rayon. DuPont's experience with rayon was an important precursor to its development and marketing of nylon.

DuPont's invention of nylon spanned an eleven-year period, ranging from the initial research program in polymers in 1927 to its announcement in 1938, shortly before the opening of the 1939 New York World's Fair. The project grew from a new organizational structure at DuPont, suggested by Charles Stine in 1927, in which the chemical department would be composed of several small research teams that would focus on "pioneering research" in chemistry and would "lead to practical applications". Harvard instructor Wallace Hume Carothers was hired to direct the polymer research group. Initially he was allowed to focus on pure research, building on and testing the theories of German chemist Hermann Staudinger. He was very successful, as research he undertook greatly improved the knowledge of polymers and contributed to the science.

Nylon was the first commercially successful synthetic thermoplastic polymer. DuPont began its research project in 1927. The first nylon, nylon 66, was synthesized on February 28, 1935, by Wallace Hume Carothers at DuPont's research facility at the DuPont Experimental Station. In response to Carothers' work, Paul Schlack at IG Farben developed nylon 6, a different molecule based on caprolactam, on January 29, 1938.

In the spring of 1930, Carothers and his team had already synthesized two new polymers. One was neoprene, a synthetic rubber greatly used during World War II. The other was a white elastic but strong paste that would later become nylon. After these discoveries, Carothers' team was made to shift its research from a more pure research approach investigating general polymerization to a more practically focused goal of finding "one chemical combination that would lend itself to industrial applications".

It was not until the beginning of 1935 that a polymer called "polymer 6-6" was finally produced. Carothers' coworker, Washington University alumnus Julian W. Hill had used a cold drawing method to produce a polyester in 1930. This cold drawing method was later used by Carothers in 1935 to fully develop nylon. The first example of nylon (nylon 6.6) was produced on February 28, 1935, at DuPont's research facility at the DuPont Experimental Station. It had all the desired properties of elasticity and strength. However, it also required a complex manufacturing process that would become the basis of industrial production in the future. DuPont obtained a patent for the polymer in September 1938, and quickly achieved a monopoly of the fiber. Carothers died 16 months before the announcement of nylon, therefore he was never able to see his success.

Nylon was first used commercially in a nylon- bristled toothbrush in 1938, followed more famously in women's stockings or "nylons" which were shown at the 1939 New York World's Fair and first sold commercially in 1940, whereupon they became an instant commercial success with 64 million pairs sold during their first year on the market. During World War II, almost all nylon production was diverted to the military for use in parachutes and parachute cord. Wartime uses of nylon and other plastics greatly increased the market for the new materials.

The production of nylon required interdepartmental collaboration between three departments at DuPont: the Department of Chemical Research, the Ammonia Department, and the Department of Rayon. Some of the key ingredients of nylon had to be produced using high pressure chemistry, the main area of expertise of the Ammonia Department. Nylon was considered a "godsend to the Ammonia Department", which had been in financial difficulties. The reactants of nylon soon constituted half of the Ammonia Department's sales and helped them come out of the period of the Great Depression by creating jobs and revenue at DuPont.

DuPont's nylon project demonstrated the importance of chemical engineering in industry, helped create jobs, and furthered the advancement of chemical engineering techniques. In fact, it developed a chemical plant that provided 1800 jobs and used the latest technologies of the time, which are still used as a model for chemical plants today. The ability to acquire a large number of chemists and engineers quickly was a huge contribution to the success of DuPont's nylon project. The first nylon plant was located at Seaford, Delaware, beginning commercial production on December 15, 1939. On October 26, 1995, the Seaford plant was designated a National Historic Chemical Landmark by the American Chemical Society.

### Supplementary Text ###
Utilisations

Le nylon a été utilisé commercialement pour la première fois en 1938 dans une brosse à dents à poils en nylon, suivi, plus célèbre, par des bas pour femmes, ou « nylons », qui ont été présentés à l'Exposition universelle de New York de 1939 et vendus commercialement pour la première fois en 1940. Son utilisation a considérablement augmenté pendant la Seconde Guerre mondiale, lorsque le besoin de tissus a explosé.

### Draft ###

Query: "Quand a été produit le premier nylon 66 ?"

Translation check: "When was first nylon 66 produced?" ● Clear chronological information request.

Task classification: Historical fact retrieval → date precision critical.

### 1. Initial Memory Scan

Nylon 66 = specific variant of synthetic polymer. Created by Carothers at DuPont. Timeline around 1935.

Key constraint: Must distinguish between:
- Nylon 66 (specific formulation)  
- vs nylon generically (family of materials)
- vs nylon 6 (competing formulation, IG Farben)

### 2. Date Triangulation

February 28, 1935 ● High confidence on this date.

Cross-reference verification:
- Wallace Hume Carothers, DuPont Experimental Station
- "Polymer 6-6" terminology in contemporary records
- Precedes commercial applications by 3-4 years

### 3. Contextual Expansion

Timeline construction:
```
1927: DuPont polymer research begins
1935 Feb 28: Nylon 66 synthesis (Carothers)  
1938: Patent filing
1939 Dec 15: Commercial production begins (Seaford, DE)
1939-1940: Commercial launch
```

### 4. Technical Verification

Nylon 66 vs Nylon 6:
- 66 = adipic acid + hexamethylene diamine monomers
- 6 = caprolactam (different synthesis path)
- Paul Schlack, IG Farben, independent development

Key insight: 66 was DuPont's breakthrough, 6 came later.

### 5. Confidence Assessment

Date accuracy: ● 99%+ confidence
- Multiple historical sources align
- Contemporary documentation exists
- No competing historical dates

∴ February 28, 1935 is correct production date for first nylon 66.

**Final answer structure:**
Direct response: February 28, 1935
Context: Carothers at DuPont Experimental Station  
Broader timeline: R&D 1927-1935 → commercialization 1938-1940
Technical note: vs nylon 6 distinction

### Answer###
Le premier nylon 66 a été produit le 28 février 1935. Cette découverte a eu lieu au sein de l'installation de recherche de DuPont, l'Experimental Station, sous la direction de Wallace Hume Carothers. Le polymère était initialement appelé "polymère 6-6" et représentait une avancée significative dans le développement des fibres synthétiques.

Ce succès s'inscrivait dans le cadre d'un projet de recherche de DuPont qui avait débuté en 1927 et s'était poursuivi pendant onze années. Carothers avait dirigé l'équipe de recherche sur les polymères, travaillant sur l'amélioration des connaissances sur ces matériaux et leur application industrielle. Le nylon 66, avec ses propriétés souhaitables d'élasticité et de résistance, nécessitait cependant un processus de fabrication complexe qui deviendrait la base de la production industrielle future.

DuPont a obtenu le brevet pour ce polymère en septembre 1938 et a rapidement établi un monopole sur cette fibre. La production commerciale a démarré le 15 décembre 1939 dans l'usine de Seaford, dans le Delaware.