ISO 8295 COF Testing For Plastic Film and Sheeting | Saicheng MXD-02 Solutions

From plastic film to finished products, and throughout transportation and storage, the friction between material surfaces consistently affects production efficiency and product quality. If friction is too high, materials are prone to sticking together during production, which in severe cases can lead to production line shutdowns. If friction is too low, materials are prone to slipping and becoming unstable during stacking, posing a risk of collapse.

ISO 8295 is the international standard for testing the coefficient of friction of plastic films and sheets. It specifies standardized test methods for measuring the kinetic and static coefficients of friction of plastic films and sheets. Through uniform test conditions and calculation procedures, it provides manufacturers with a repeatable and quantifiable evaluation method for material research and development, formulation optimization, and quality control during production.

What is ISO 8295?

ISO 8295 is a standard method developed by the International Organization for Standardization (ISO) for determining the kinetic and static coefficients of friction of plastic films and sheets. It establishes a precise and repeatable framework for quantifying the response behavior of materials under mechanical stress.

Static Coefficient of Friction

Measures the force required to generate relative motion between plastic films and sheets and the contact surfaces of the material itself or other materials. It represents the maximum resistance that must be overcome for the material to transition from complete rest to sliding.

$u_s=F_s/F_p$

$u_s$: Static coefficient of friction (unitless). Represents the starting resistance.

$F_s$: Maximum friction force, in newtons (N). The absolute peak force required for the material to transition from a state of rest to a state of sliding.

$F_p$: Normal force, in newtons (N). The downward force is applied perpendicular to the film surface by the slider.

Kinetic Coefficient of Friction

A measure of the frictional force required to maintain uniform, stable relative motion between the plastic film or sheet and the contact surface of its own material or another material.

_{$u_k=F_d/F_p$}

$u_k$: Coefficient of kinetic friction. Represents the resistance to sustained sliding on the surface of a material.
$F_d$: Kinetic friction force, measured in newtons (N). Represents the average friction force measured over a specified sliding distance during continuous sliding of the specimen.
$F_p$: Normal force, measured in newtons (N). The downward force exerted perpendicularly by the slider on the film surface.

Step-by-Step ISO 8295 Test Procedure

1. Environmental and Sample Conditioning

The friction properties of polymer material surfaces are highly sensitive to environmental factors; the test environment for the samples is established in accordance with the standards.

• Temperature and Humidity: All samples must be conditioned in an environment with a temperature of $23^\circ\text{C} \pm 2^\circ\text{C}$and a relative humidity of $50\% \pm 5\%$.
• Conditioning Time: Unless otherwise specified, specimens must be kept in the controlled environment for at least 16 hours.
• Specimen Surface: Keep the specimen surface clean, free of contamination, grease, and fingerprints. Operators must wear clean, lint-free gloves when handling, cutting, and mounting specimens.

2. Specimen Preparation

• Horizontal Specimen: Cut a specimen with a minimum width of 80mm and a length of approximately 200mm.
• Sled Specimen: Cut a square specimen with side lengths of approximately 120mm *120mm.

3. Instrument Setup

• Leveling: Ensure that the test platform is completely level relative to the floor.
• Calibrate and zero the load cell.
• Set the Speed: Set the speed of the crosshead or drive mechanism to a constant value of $100\,\text{mm/min} \pm 10\,\text{mm/min}$.

4. Install the Specimen

Scenario A: Film-to-Film Testing

Securing the Plane Specimen: Place the 200mm plane specimen completely flat on the horizontal test bench, with the test surface facing up. Secure both ends of the specimen firmly using double-sided tape or mechanical clamps.

Securing a Flat Specimen: Place the 120mm sled specimen over the bottom face of the 200g square sled (63mm *63mm). Wrap the edges smoothly up the sides of the sled and secure them using the sled’s integrated mechanical springs or clamping bars. Ensure the target test surface faces outward.

Scenario B: Film-to-Metal or Other Material Testing

Preparing the Plane: Retrieve the flat film specimen. Ensure that an approved horizontal test bench is used and that it is completely dry.

Wrapping the Sled Specimen: Secure the sled film specimen to the sled exactly as described in Scenario A.

5. Start Testing

Gently lower the wrapped sled onto the starting end of the horizontal test bed. Before starting the equipment, allow the sled to rest motionless on the surface for 15 seconds. Connect a flexible, inelastic wire or spring link between the sled and the load cell. Start the instrument, the motor will pull the sled at a constant speed of 100mm/min until the minimum distance of continuous sliding of the sled reaches 60mm.

6. Data Analysis and Reporting

Upon completion of the test, the system automatically analyzes the friction force curve, extracts the peak static friction force (Fs) and the average kinetic friction force (Fd) during the steady-state sliding phase, and calculates the static and kinetic coefficients of friction (COF). Finally, a standardized report containing the test results, key parameters, and specimen information is generated.

ISO 8295 vs. ASTM D1894: What’s the Difference?

Parameter	ISO 8295 Standard	ASTM D1894 Standard
Sled Mass / Weight	Strictly 200 g $\pm$ 2 g (Exerting 1.96 N)	Typically 200 g $\pm$ 5 g (Other weights allowable)
Sled Dimensions	63 mm x 63 mm	63.5 mm x 63.5 mm
Testing Speed	100 mm/min (500 mm/min for special cases)	150 mm/min $\pm$30 mm/min
Spring Attachment	Requires a specific tension spring for static COF	Directly linked; software filtering preferred

The Importance of Implementing the ISO 8295 Standard

Ensuring Consistency and Comparability in Global Testing

As a globally recognized international standard, ISO 8295 provides a unified testing framework for regions worldwide, ensuring the comparability and consistency of data.

Driving Material R&D and Process Control Optimization

By quantifying the friction properties of plastic films and sheets, manufacturers can precisely optimize processing parameters. At the same time, by evaluating the effectiveness of additives such as slip agents and anti-blocking agents, R&D personnel can precisely optimize resin formulations and control material surface properties.

Ensuring Smooth Operation of Automated Packaging Systems

By effectively predicting and improving material slippage behavior on high-speed production lines through kinetic and static coefficient of friction measurements, this standard enhances the stability of high-speed feeding, the precision of seal alignment, and the anti-slip performance of stacked finished products after packaging.

Reducing Production Risks and Operating Costs

By avoiding the potential risks of film being too sticky (causing winding difficulties) or too slippery (causing the roll to collapse or slip during winding), equipment downtime is significantly reduced, thereby lowering production costs.

Eliminating Technical Barriers to International Trade

As a universally recognized language of international trade, it serves as a bridge for communication among global suppliers and manufacturers.

ISO 8295 Standard COF Testing Industrial Applications

• Food and Consumer Goods: Vertical/Horizontal Form-Fill-Seal (VFFS/HFFS) machines
• New Energy Vehicles and Battery Manufacturing: Polyolefin films used inside lithium-ion batteries
• Medical Devices and Pharmaceutical Packaging: IV bags, blister pack base films, high-vacuum sterile packaging, and modern wound dressing films.
• Printing and Post-Press Processing Industry: The feeding process of base films for laminated flexible packaging (e.g., PET, BOPP) on high-speed printing presses.
• Warehousing, Logistics, and Bulk Commodity Packaging: Palletizing and stacking of cement bags, heavy-duty packaging bags (FFS bags), pet food bags, and stretch wrap.

5 Key Factors Affecting ISO 8295 Test Results

• Film Surface Conditions: Roughness, coating uniformity, contaminants, fingerprints, additives, and other factors affect the determination of the coefficient of friction.
• Ambient Temperature and Humidity: Plastic films are extremely sensitive to environmental conditions; temperature can alter the migration rate of additives, while humidity can cause viscosity due to microscopic water films.
• Equipment Parameters: Slider mass and pressure, stiffness of the drive system, and test speed.
• Material-specific Properties: Surface roughness, charge accumulation.
• Operator Procedures: Strictly prevent surface contamination during specimen preparation; ensure specimens are perfectly flat, free of wrinkles, and have smooth edges. Testing the same test point repeatedly is strictly prohibited.

The factors mentioned above indicate that reliable coefficient of friction (COF) test results depend not only on testing standards but also on material properties, test conditions, equipment parameters, and operating procedures. For a more comprehensive understanding of coefficient of friction testing methods, standards, and applications, please refer to our comprehensive guide on coefficient of friction testing.

Saicheng High-Precision Coefficient of Friction Tester

Saicheng’s MXD-02 COF Tester is designed in strict accordance with ISO 8295, providing highly accurate, reliable, and consistent test data to help manufacturers achieve precise quality control and meet compliance requirements.

• 1–800 mm/min stepless speed control
• 0.5% FS high-precision force sensor
• Standard 200 g precision slider
• User-friendly interface
• System-generated real-time force curves
• Customization services
• Data storage with audit trail support

Conclusion

ISO 8295, a globally recognized international standard, provides a consistent and verifiable basis for testing the friction properties of materials worldwide. In the global plastics and flexible packaging markets, surface consistency is a key factor in determining competitive advantage. By implementing the test procedures outlined in this standard, manufacturers can precisely control the friction properties of their materials, avoid risks associated with excessive or insufficient friction, and ensure that products perform as expected throughout their entire lifecycle.

At Saicheng Instrument, our MXD-02 COF Tester is designed in strict accordance with ISO 8295 standard to provide repeatable, quantifiable data you require.