Rub Resistance Testing of Printed Matter: Standards, Methods, and Applications

Rub resistance testing, also known as print abrasion resistance testing, evaluates how well printed inks, coatings, and varnishes on paper, paperboard, film, and labels withstand repeated mechanical rubbing during handling, filling, transport, and end use. This guide explains the testing principle, applicable standards such as ASTM D5264 and GB/T 7705, common test items, sample requirements, evaluation criteria, and practical applications, providing a reference for manufacturers, brand owners, and accredited third-party laboratories.

Technical Overview

Rub resistance testing of printed matter is a laboratory procedure that measures the ability of a printed ink film, overprint varnish, or coated surface to resist mechanical damage caused by repeated rubbing, scuffing, and surface-to-surface contact. During production, packaging, filling, distribution, and retail display, printed products are constantly subjected to friction against machinery guides, other packages, and transport containers. If the printed layer has poor rub resistance, the result can be ink smearing, loss of image density, color transfer to adjacent surfaces, or complete removal of printed information such as barcodes, batch numbers, and safety warnings.

In a typical test, a printed specimen is secured on a reciprocating rub tester and rubbed against an unprinted counterface (or against itself) under a defined load for a specified number of strokes. After testing, the specimen and the counterface are examined for abrasion damage, ink transfer, and color change. The severity of deterioration is rated either visually against a defined scale or instrumentally using densitometry or colorimetry.

Commonly referenced standards and conditioning procedures for this test include:

• ASTM D5264 — abrasion resistance of printed materials using a reciprocating linear rub tester
• TAPPI T830 — ink rub resistance of paperboard and printed cartons
• GB/T 7705 and GB/T 7706 — Chinese national standards for decorative printed products, including rub resistance requirements for lithographic and gravure prints
• AATCC 8 — crockmeter method for colorfastness to dry and wet rubbing, applied to printed textiles and flexible substrates
• ISO 187 and ASTM D685 — conditioning of paper and board samples prior to testing
• ISO 11664 / CIE colorimetry — instrumental measurement of color difference before and after rubbing

Testing Samples

Paper and Paperboard Packaging

Folding cartons, blister cards, shelf-ready packaging, and corrugated shipping boxes are among the most frequently tested products. These items experience severe abrasion during filling-line operation, case packing, and pallet transport, so both printed ink and any varnish or lamination layer are evaluated.

Labels and Narrow-Web Printed Products

Pressure-sensitive labels, wrap-around beverage labels, wine labels, and shrink sleeves are tested for both dry and wet rub performance. Bottle labels in particular must survive ice-bucket immersion, condensation, and high-speed label application without ink loss or bleed.

Flexible Films and Laminates

Surface-printed and reverse-printed plastic films, laminated pouches, and sachets are tested to verify the durability of the printed layer against friction on vertical form-fill-seal equipment and during distribution. The test also checks whether printed ink transfers onto the inner sealing or food-contact side of the structure.

Commercial, Industrial, and Security Print

Magazine covers, direct-mail pieces, lottery and admission tickets, pharmaceutical serialization markings, and identification documents are tested to confirm that critical printed information remains legible after repeated handling and abrasion.

Testing Items

Depending on the product specification and end-use environment, the following test items are typically performed:

• Dry rub resistance — durability of the print under dry surface-to-surface rubbing
• Wet rub resistance — durability when the surface or counterface is wetted with water or another specified liquid
• Ink transfer (set-off) — degree to which ink transfers from the print onto a clean receptor surface
• Print durability after abrasion — retention of color density, gloss, and legibility of barcodes and variable data
• Coating and varnish abrasion resistance — resistance of overprint varnish, UV coating, or metallized layers to marring and scuffing
• Colorfastness to rubbing — assessment of color pickup on a white crock cloth, rated with grey scales

Testing Methods

Specimen Preparation and Conditioning

Specimens are cut to the dimensions required by the apparatus, typically rectangular strips free from wrinkles, curl, and visible defects, taken from representative production material. Unless otherwise specified, samples are conditioned at 23 ± 2 °C and 50 ± 5% relative humidity for at least 24 hours before testing. A minimum of three to five replicate specimens is recommended because the test is sensitive to print uniformity.

Dry Rub Test

The printed specimen is fixed on the bed or on the weighted head of a reciprocating rub tester, and an unprinted receptor sheet of similar stock is clamped on the opposing surface. A standard dead weight, commonly 2 lb (approximately 0.9 kg) with 4 lb (approximately 1.8 kg) used for more severe conditions, is applied while the machine performs a fixed stroke length of about 50 mm at a constant rate. The test runs for a specified number of strokes, commonly 25, 50, or 100, after which the specimen and receptor are assessed for abrasion, smudging, and transferred ink. This approach follows the principle of ASTM D5264 and TAPPI T830.

Wet Rub Test

The wet rub test follows the same mechanical arrangement, but the receptor cloth or the printed surface is moistened with a defined quantity of water or another relevant liquid such as beverage simulants, cleaning agents, or sweat solutions. This test simulates exposure to condensation, ice buckets, wet hands, and humid transport conditions, and is essential for labels and flexible packaging intended for chilled or wet environments.

Ink Transfer and Set-Off Assessment

To quantify set-off, a clean white receptor is rubbed against the print under the standard load and stroke count. The receptor is then examined visually or instrumentally for the amount of transferred color, often rated on a 0 to 5 scale or by grey-scale contrast assessment. This check is particularly important for stacked products such as carbonless business forms, cartons packed face-to-face, and reels of printed labels.

Evaluation and Pass Criteria

Results are evaluated by one or more of the following approaches: visual rating of surface damage against reference photographs or a defined numerical scale; measurement of reflection density or color difference before and after rubbing; assessment of the receptor for ink transfer; and verification that barcodes and variable data remain scannable and legible. Typical acceptance criteria require no heavy ink transfer, no exposure of substrate, and a color difference within an agreed limit, for example a maximum change before and after the specified number of rubs. Because visual rating involves some subjectivity, comparison against mutually agreed reference samples between supplier and buyer is strongly recommended.

Applications

Rub resistance testing is used throughout the printing and packaging supply chain for purposes such as:

• Incoming quality control of printed cartons, labels, and flexible packaging before filling or converting
• Qualification of ink, coating, and varnish formulations during development
• Verification of substrate and ink compatibility, including UV-cured and water-based systems
• Failure analysis of scuffed or smeared products returned from production lines or the field
• Compliance demonstration against buyer specifications and national product standards such as GB/T 7705 and GB/T 7706
• Validation of durability for pharmaceutical serialization, track-and-trace codes, and other regulatory markings
• Shelf-life and transport simulation for export packaging and premium consumer goods

FAQ

What is rub resistance testing of printed matter?

It is a laboratory test that rubs a printed specimen against a counterface under a controlled load, stroke count, and speed, then evaluates the print for abrasion damage, ink transfer, and color change. It predicts how the print will survive handling, transport, and end-use friction.

Which standards are most commonly applied?

ASTM D5264 is the most widely used method for printed materials using a reciprocating rub tester, while TAPPI T830 is common for printed paperboard. GB/T 7705 and GB/T 7706 specify rub resistance requirements for decorative printed products in China, and AATCC 8 is applied to printed textiles and flexible substrates using the crockmeter principle.

What is the difference between dry rub and wet rub testing?

Dry rub testing evaluates the print under dry contact conditions and addresses general scuffing during handling and transport. Wet rub testing introduces water or another liquid to the contact zone and is required for products exposed to condensation, ice buckets, chilled display, or repeated wet cleaning.

How many strokes and what load are typically used?

Typical procedures use a 2 lb (about 0.9 kg) weight for 25 to 100 strokes, with heavier loads and extended stroke counts applied for severe-duty specifications. The exact conditions should always follow the applicable standard or the agreed product specification.

How are results judged as pass or fail?

Common criteria include no significant ink removal or substrate exposure, no more than slight transfer onto the white receptor, color difference within an agreed tolerance measured instrumentally, and continued scannability of barcodes and printed data. Grey-scale or numerical visual ratings are used when a quantitative limit is specified.

What sample size and quantity are required?

Specimens are usually rectangular strips matching the clamp dimensions of the tester, cut from representative production samples. A minimum of three to five specimens per condition is recommended, and samples should be conditioned at 23 ± 2 °C and 50 ± 5% relative humidity before testing.

What factors most strongly influence rub resistance results?

Key factors include ink film thickness and formulation, degree of curing or drying, substrate smoothness and absorbency, presence and type of overprint varnish or lamination, ambient humidity during printing and testing, and the pressure and dwell time between printing and testing. Consistent control of these variables is essential for reproducible results.