ISO 16532-1 Paper and Board - Determination of Oil Resistance - Part 1: Permeability Test

The standard "ISO 16532-1 Paper and board - Determination of oil resistance - Part 1: Permeation test," developed by the International Organization for Standardization (ISO), describes a method for determining the grease resistance of paper and board. Paper and board can be tested with or without wrinkles. The test primarily aims to determine a level of grease resistance by determining the time it takes for a simulated oil material (palm kernel oil) to penetrate (permeate) the sheet for papers such as food paperboard, greaseproof paper, and vegetable parchment. It is also applicable to paper and board whose interior or surface is sized with organophobic materials or made grease resistant by plastic extrusion coating.

For the purposes of this standard, the following terms and definitions apply:

• Grease resistance refers to the ability of paper or board to resist the formation of surface stains or the penetration of grease into the sheet.
• Grease permeability refers to the ability of paper or board to resist grease penetration into the substrate. Grease permeability is defined by two properties: breakthrough time (actual breakthrough time) and apparent breakthrough time.
• Penetration time refers to the time between the application of test grease along with a weight to one side of the test piece and the penetration of the grease to the other side of the test piece.
• The exposure time refers to the time elapsed between the application of test grease to one side of the test piece with a weight and the first visual detection of grease spots (or partial penetration of the grease into the sheet). The primary purpose of this standard is to determine the breakthrough time. However, the breakthrough time may be of interest in special cases, such as when examining paper and board sized internally or on the surface with organophobic materials or paper and board made grease-resistant by a plastic extrusion coating. The two tests can be combined, in which case the breakthrough time is determined before the breakthrough time. For many grades of paper and board, the breakthrough times and breakthrough times are nearly identical.

Test pieces are placed on a glass plate with or without a layer of cellulose filler, and dyed palm kernel oil, along with a weight, is applied to the top of the test pieces. The time elapsed until an indication of partial or actual grease penetration through each test piece is recorded is as described in the following paragraphs. To determine actual grease penetration (penetration) through the test pieces, the endpoint is determined by visually observing the smearing of the cellulose filler while in contact with the test pieces. In practice, the time required for the cellulose filler to penetrate is included, but this is very short and can therefore be neglected. To determine partial grease penetration (penetration), the endpoint is determined when the eye can detect grease spots or smudges without the aid of the cellulose filler.

Standard grease consisting of palm kernel oil or other oils with the following properties is used as a reagent in the tests:

• Liquefaction temperature: 27 degrees to 29 degrees
• Dynamic viscosity: 33,5 mPa·s to 35,0 mPa·s
• Refractive index at 40 degrees: 1,44 to 1,45
• Dyed with 0,25 percent (mass fraction) Sudan red or similar oil-soluble dye

If the grease is lumpy, it should be homogenized with a spatula before use. Greases other than standardized materials may be used if they meet the specifications above; this fact must be noted in the test report.

The ISO 16532-1 standard, which specifies the method for determining the oil resistance of paper and board by permeation testing, is deemed necessary for the following reasons:

• Ensuring product quality in packaging: Many paper and paperboard products, such as food paperboard, greaseproof paper, and vegetable parchment, are used in packaging food (e.g., pet food or human consumables) and other oil-sensitive materials. This standard ensures that these materials resist oil penetration, preventing leaks, contamination, or damage to the packaged products.
• Standardized test for consistency: This standard provides a uniform method for measuring how long it takes for a simulated oil material (such as palm kernel oil) to penetrate paper or board. This allows manufacturers, suppliers, and customers to reliably compare oil resistance across products, ensuring consistent performance.
• Supporting materials development: This standard applies to papers treated with organophobic materials (e.g., fluorocarbons) or plastic extrusion coatings. It helps manufacturers evaluate and refine treatments to increase grease resistance, which is critical for developing durable and effective packaging solutions.
• Preventing aesthetic and functional problems: Grease penetration can cause unsightly stains or weaken the structural integrity of paper and board. Testing for grease resistance ensures that standard packaging remains visually appealing and functional, which is especially important for consumer products.
• Regulatory and safety compliance: This standard ensures that grease resistance complies with safety and regulatory requirements to prevent contamination in industries such as food packaging. This standard provides a measurable benchmark for meeting these standards, protecting both consumers and manufacturers.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, boasts a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the "ISO 16532-1 Paper and board - Determination of oil resistance - Part 1: Permeability test" standard.