Main Applications:
This machine tests the degree of damage and discoloration on dyed uppers and lining leather after friction. The test method involves wrapping dry or wet white wool felt around the friction surface and then rubbing the test piece back and forth against the test bench.
Compliant Standards:
ISO 11640:1998. SatraTM 173. ISO-11640. QB/T 2537-2001. QB/T 2882-2007. ISO 11640. SATRA PM 173. QB/T 2537-2001. DIN 4843. QB/T 2226. GB/T 20991 Section 7.3
Scope of Application:
This instrument is used to test the rubbing fastness of leather surfaces. It assesses the amount of color transferred from the specimen to the rubbing pad by determining the degree of "color loss" of the leather surface or coating.
Working Principle of a Leather Crockmeter
A leather crockmeter evaluates the color retention of leather by simulating the various abrasive forces to which a leather surface may be subjected in daily use. The instrument's core components include a crockmeter head, a sample holder, and a motion control system. The crockmeter head, typically made of standardized white wool felt or cotton cloth, rubs the leather sample surface in a reciprocating or rotating motion under a specified pressure. During the test, the instrument precisely controls parameters such as the number of rubbing strokes, pressure, and speed to ensure consistent and repeatable testing conditions.
After the test, the degree of color transfer from the rubbing material is assessed using a colorimetric chart or colorimeter to determine the leather's color fastness grade. This mechanical simulation test quickly and objectively reflects the color stability of leather products in actual use, providing reliable data for product quality control. Modern, high-end models are also equipped with digital control systems and automated evaluation software, further improving testing efficiency and accuracy.
Instrument Operation Procedures and Precautions
When using a leather crockmeter for testing, first prepare the sample and rubbing cloth according to standard requirements. The specimen should be cut from a representative area of the leather, meeting the specified dimensions and possessing a smooth, wrinkle-free surface. Secure the specimen to the test platform, ensuring it is tight and free of looseness. For dry friction testing, directly attach a dry friction cloth. For wet friction testing, first wet the cloth and wring it to the specified moisture content (usually 95-100%).
Set the test parameters, including the number of frictions (usually 20), the friction speed (approximately 1Hz), and the pressure (usually 5N). Start the instrument and test. After completion, remove the friction cloth and compare the staining level against a gray scale in a standard light booth. The evaluation should be performed independently by at least two trained operators, and the average result should be used as the final result.
Operating precautions include: the instrument should be placed on a stable surface to avoid vibration interference; the pressure system and travel range should be calibrated regularly; the friction cloth must meet standard requirements and cannot be reused; the testing environment should maintain a standard temperature and humidity (usually 20±2°C, 65±2%RH); different color areas should be tested separately and recorded; and the instrument should be cleaned promptly after testing, especially after wet friction testing to prevent rust.
Key Considerations and Technical Parameter Analysis
When selecting a leather crockmeter, first consider testing requirements and standards compliance. Different industries and applications may require compliance with specific standards. For example, the footwear industry may prioritize SATRA standards, while automotive interior suppliers may prioritize ISO methods. Key parameters include: friction mode (reciprocating or rotary), maximum pressure (typically adjustable from 5-10N), friction travel (typically 60-100mm), counting range (typically 0-999 counts), and speed control (approximately 1Hz).
The instrument should be sturdy and durable, with smooth, shake-free movement of the friction head and uniform and accurate pressure application. High-quality models typically utilize precision linear guides and servo control systems to ensure consistent testing. Additional features such as touchscreen operation, multi-program storage, and automatic report generation can enhance efficiency. Regarding price, basic domestic instruments range from approximately 20.000 to 50.000 yuan, while high-end imported models can cost over 100.000 yuan. This consideration should be considered based on budget and long-term needs.
After-sales service is equally important, including installation training, regular calibration, and repair response. It's recommended to choose a supplier with a professional technical team and a sufficient inventory of spare parts. For multi-standard testing needs, consider modular designs that allow you to meet different standards by replacing accessories.
Applications and Importance
Leather crockmeters are widely used across various industries. In footwear manufacturing, they are used to test the color fastness of leather shoe uppers, linings, and other parts to ensure they don't stain socks or skin during wear. The leather goods and luggage industry focuses on the color fastness of frequently touched areas like handles and straps. The automotive interior industry places extremely high demands on the color fastness of leather components like seats and steering wheels, as sunlight and frequent friction accelerate color change.
The furniture industry uses them to assess the durability of leather furniture like sofas and chairs, especially light-colored leathers, which are more susceptible to staining. The apparel industry tests leather jackets and pants to ensure color stability during washing and wearing. These tests are not only important for product aesthetics but also for safety and health. For example, some dyes can transfer to skin through friction and cause allergies.
Scientific color fastness testing allows companies to select appropriate leather materials and dyeing and finishing processes during product development, monitor quality stability during production, and conduct final inspections before shipment to prevent customer complaints. Test data also serves as a crucial basis for addressing quality disputes and meeting regulatory requirements. With rising consumer awareness of quality and increasingly stringent environmental regulations, the importance of leather color fastness testing will only grow.
