How to Read a Lab Report: A Guide for Non-Engineers

In the flexible packaging industry, decision-makers are frequently handed technical lab reports filled with complex acronyms, charts, and data points. Whether you are in procurement trying to validate a new supplier’s cost-saving film, or a marketing manager ensuring that a new eco-friendly pouch won’t compromise product freshness, understanding these metrics is vital.

You don’t need a degree in materials science to make informed decisions. This guide breaks down the most common testing protocols found in flexible packaging lab reports—including OTR, MVTR, DSC, Optical Microscopy, and FTIR—explaining what they mean in plain English and why they matter to your business.

1. Oxygen Transmission Rate (OTR)

• What it measures: OTR quantifies how much oxygen gas passes through a specific area of a plastic film over a 24-hour period.
• The units to look for: Typically expressed as cc/100 in²/day (or cc/m²/day in metric).
• Why non-engineers should care: Oxygen is the enemy of freshness for many products. It causes oils to go rancid, alters flavor profiles, changes product colors, and allows aerobic bacteria or mold to grow. If you are packaging snacks, coffee, meats, or pet food, you want the OTR number to be as low as possible.
• Real-world application: If procurement wants to switch to a cheaper film structure, look at the OTR. If the new film has a significantly higher OTR than your current standard, your product’s shelf life will shrink, likely resulting in a spike in retail returns.

2. Moisture Vapor Transmission Rate (MVTR)

• What it measures: Also known as Water Vapor Transmission Rate (WVTR), MVTR measures the passage of water vapor through a packaging material over 24 hours.
• The units to look for: Typically expressed as g/100 in²/day (or g/m²/day).
• Why non-engineers should care: MVTR tells you how well a package keeps moisture out—or keeps it in. For dry products like powdered drink mixes, crackers, and pharmaceuticals, a high MVTR means moisture will seep in, causing clumping, staleness, or degradation. Conversely, for moist products like wet pet food or wipes, a high MVTR means the product will dry out on the shelf.
• Real-world application: Marketing may design a beautiful new clear window feature on a pouch. However, substituting a solid barrier layer for a transparent window can drastically alter the MVTR. Checking the MVTR ensures that visual aesthetics haven’t compromised the physical protection of the product.

3. Differential Scanning Calorimetry (DSC)

• What it measures: Unlike OTR and MVTR which measure barrier performance, DSC is a thermal analysis technique. It heats a material sample up and measures how much energy it absorbs or releases, plotting a curve that identifies thermal transitions like melting points and crystallinity.
• What it looks like on a report: A graph with distinct peaks and valleys, often referred to as a “thermal fingerprint.”
• Why non-engineers should care: DSC is an incredible tool for verifying material consistency and reverse engineering competitive samples. It helps identify the thermal behavior of polymers making up a film structure.
• Real-world application: If a supplier promises that a new material blend is an exact match for your current film, a comparison of their DSC profiles will tell the absolute truth. If the melting peaks don’t align, the materials are different. This variance can lead to unpredictable behaviors on your high-speed filling lines or cause failures during heat-sealing.

4. Optical Microscopy

• What it measures: Optical Microscopy uses high-powered specialized microscopes and precision cross-sectioning techniques to visually examine the individual layers of a flexible film.
• What it looks like on a report: A high-resolution color photograph displaying a microscopic cross-section of the film, accompanied by exact micrometer or mil thickness measurements for every individual layer.
• Why non-engineers should care: Modern flexible packaging looks like a single thin sheet of plastic, but it is actually an engineered stack of multiple distinct layers (such as outer skins, barrier materials, tie layers, and sealant webs). Microscopy physically proves how many layers exist and exactly how thick each one is.
• Real-world application: If a competitor is outperforming you or offering a lower-cost package, Optical Microscopy lets you “peek behind the curtain” to see their exact film architecture. It is also an indispensable auditing tool to verify that your current converter is delivering the precise layer distribution you are paying for.

5. Fourier Transform Infrared Spectroscopy (FTIR)

• What it measures: FTIR shines infrared light through a material sample and measures which specific wavelengths are absorbed. Because different chemical bonds absorb light in unique ways, this test creates an unmistakable chemical spectrum.
• What it looks like on a report: A complex spectral graph with sharp downward-pointing bands, serving as an absolute molecular ID card for the material.
• Why non-engineers should care: If DSC gives you the broad physical fingerprint of a material, FTIR provides its definitive chemical identity. It tells you exactly what family of polymers you are looking at (e.g., Polyethylene, Polypropylene, Nylon, or PET) and can identify unknown contaminants or additives.
• Real-world application: When resolving an unexpected field failure—such as layers suddenly peeling apart or an off-odor—FTIR can instantly pinpoint the culprit. It can identify if an incorrect resin was introduced in the compounding phase, or if a chemical contaminant is interfering with your film’s performance.

Demystifying Data with Flex-Pack Engineering

A lab report shouldn’t be a document you simply file away and ignore; it should be a powerful tool that guides your purchasing, marketing, and design strategies. However, interpreting raw data points without context can leave your business vulnerable to unexpected liabilities.

That is where Flex-Pack Engineering excels. As an independent, third-party testing facility, we do more than generate numbers—we translate complex ASTM and ISO laboratory data into actionable commercial insights.

We help procurement teams validate cost-reduction or down-gauging claims without sacrificing performance, and we give marketing and product development teams the empirical data they need to innovate safely. From full physical testing and optical microscopy to custom polymer compounding and FTIR analysis, our laboratory provides the definitive answers your brand needs.

Stop guessing what your packaging data means. Contact Flex-Pack Engineering today at 888-300-1482 to partner with experts who can help you optimize your flexible packaging structures.