Elastomer Cure Dates, Shelf Life and Service Life （弹性体治疗日期、保质期和使用寿命）.pdfVIP

Elastomer Cure Dates, Shelf Life and Service Life Explained We are often asked what the shelf life is for a particular elastomer(NBR, FKM, and VMQ typically). If you “google” the question several inconsistent answers are provided. NBR can be 3-5 years; 5-10 years; 5 years etc. Why isn’t there a consistent answer for a simple question? Before we answer that question and pose several other questions routinely asked, let’s examine some definitions. Cure Date – Curing is the heat-induced process whereby the long chains of the rubber molecules become cross-linked by a vulcanizing agent to form three- dimensional elastic structures. The Cure Date is the date that the rubber is fully molded in this process. Shelf(Storage) Life – the maximum period of time, from cure date, to the date an elastomeric product is used as a component part in assemblies, sub-assemblies, and systems. During the shelf life time the stored elastomeric product is expected to retain its characteristics, as originally specified. Service Life – is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be serviceable or supported by its manufacturer. Since elastomers are used in many products, the service life would be dependent on the product manufactured. There are several primary factors that influence the service life of an elastomer in a finished product: heat, corrosion, wear and cracking. There are several standards for defining the shelf life of an elastomer. The standard used by the manufacturer is mostly dependent on where the product is manufactured, or what market the product will be used. These standards include: ASTM D1418 American Society of Testing Materials: Standard Practice for Rubber Materials DIN 7716 German National Standard: Requirements for Storage, Cleaning Maintenance for Rubber Products BS 3F68:1977 British Standa