Hypalonand the Montreal Protocol

What is the Montreal Protocol?

The Montreal Protocol on Substances That Deplete the Ozone Layer is a landmark international agreement designed to protect the stratospheric ozone layer. The treaty was originally signed in 1987 and amended in 1990, 1992 and 1997. The Montreal Protocol aims to reduce and eventually eliminate the emissions of ozone depleting subtances. The Montreal Protocol applies to the manufacture of Hypalon® chlorosulfonated polyethylene because DuPont Performance Elastomers uses a chemical that is listed by the protocol as a "controlled substance" (carbon tetrachloride).

In November 1998, Montreal Protocol Parties addressed carbon tetrachloride emissions including those relative to the Hypalon® manufacturing process. The Parties' Decision X/14 identifies the use of carbon tetrachloride in the Hypalon® process as a process agent and exempts such process agent applications in developed countries that have insignificant emissions and requires similar emission reductions in undeveloped countries. A report is to be made to the Parties in 2001 on progress in reducing emissions from process agent uses. This decision provides the same exemption from ozone depleting substance controls as previous feedstock exemptions.

In the United States, the EPA has determined that the Hypalon® process qualifies as a feedstock use of carbon tetrachloride and is therefore exempted from the protocol under Decision IV/12. As part of DuPont Performance Elastomers' product stewardship philosophy, the Hypalon® process continues to reduce emissions by improving process efficiencies, operations and maintenance. In addition, DuPont Performance Elastomers continues to track any Montreal Protocol or EPA regulatory developments for potential future impacts.

What is the Hypalon® Chemistry and What Role Does CCL4 Play?

Process chemistry for making Hypalon® involves the following reactions:

1. Carbon Tetrachloride (CC14)(polyethylene) ----->Chloroform (CHC13)
2. Chloroform (CHC13)(caustic) ----->Carbon Monoxide + Sodium

Formate Reaction 1 is a significant reaction dependent on product type. Reaction 2 essentially consumes all the chloroform produced and occurs during the neutralization phase of the process.

99.95% of the total carbon tetrachloride used in this process is recycled, transformed to a non-ozone depleting substance or incinerated.

What is a Feedstock as Defined by the Montreal Protocol?

A feedstock is a a controlled substance that undergoes transformation in a process in which it is converted from its original composition except for insignificant trace emissions as allowed by Decision IV/12.

What is a Process Agent as Defined by the Montreal Protocol?

A process agent is a controlled substance that because of its unique chemical and/or physical properties, facilitates an intended chemical reaction and/or inhibits an unintended chemical reaction.

What is a Controlled Substance as Defined by the Montreal Protocol?

The definition of "controlled substance" in paragraph 4 of Article 1 of the Montreal Protocol has been amended several times to exclude certain uses of ozone-depleting substances, including:

• Feedstocks, residuals in products or recycled/reused ozone depleting substances
• Insignificant quantities from unreacted feedstock, process agents, or emissions from product manufacturing or handling.