These properties pages answer many of the questions that are often asked about film properties, including:

1. How is this property measured?
2. What is the ASTM test method number?
3. What affects the property?

We also discuss when and why the property is important. Sometimes we compare typical OPP property values with the values for other films. In short, we have tried to design a complete and organized resource about the properties used to characterize ExxonMobil Chemical flexible packaging films.

If a property exists in at least one product characteristics page, then it is included in this section. The discussion about each property follows the same format.

• Title, which states the property name.
• Test Methods, which lists the ExxonMobil Chemical test procedure(s) number(s) and the related industry standard test method(s). ISO protocol governs the numbering system, and these numbers are long. For simplicity, only the last three digits of the ISO procedure number are stated. For example, the ExxonMobil test procedure for haze is NAF-OPP-4.10-QCT-3-444 but it is referred to as ExxonMobil Chemical # 444.
• Definition section contains a brief, but precise, overview of what the measurement is and its units.
• Relevance section, within which the importance of the property is discussed. Sometimes this entails describing production methods, applications, or a comparison of OPP film to other film types. Occasionally, this section explains why a property is not relevant.
• What Affects section, which describes how material, product design, and process impact the property value. Sometimes how the property is controlled to target is discussed.
• Test Principles section, which illustrates the basic test. Key differences between the industry standard test method and the ExxonMobil Chemical test method are explained here.
• Related Terminology, which defines industry terms that are associated with the property or that were used in the body of the discussion.

Please note that illustrations and graphs, in most cases, provide data in US standard units.