Interpretation of GB/T12586A Test Method

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Date: 2025-11-14Read: 10

1、 Standard core positioning and scope of application

GB/T12586 is the core basic standard in the field of rubber or plastic coated fabrics in China. The current version was released in 2017 (replacing the 2003 version), corresponding to the international standard ISO 7854:2016 (MOD), and belongs toProduct mechanical performance testing method standardsIts core positioning is to quantitatively evaluate the material's ability to resist bending damage by simulating the usage scenarios of coated fabrics under repeated bending conditions, providing technical basis for product quality control, material selection, and application reliability.

The scope of application covers various types of rubber or plastic coated fabrics, including but not limited to: industrial conveyor belts, waterproofing membranes, tent fabrics, inflatable product fabrics, fire hoses, protective clothing fabrics, etc. It should be noted that the standard explicitly excludes foam coated materials and rigid coated fabrics with a thickness of more than 3mm (for such materials, please refer to special standards such as GB/T 1690-2010).

2、 Core technical requirements and terminology definitions

1. Definition of key terms

Flexion and destructionRefers to the failure phenomenon of coating layer cracking, base fabric peeling off from coating layer, or base fabric fiber fracture caused by internal stress concentration of materials under repeated folding and bending.

Flexion frequencyThe cumulative number of times the sample completes the "folding unfolding" cycle during the testing process is the core indicator for evaluating the flexural resistance performance.

Qualification criteriaAfter the specified number of bending cycles, the coating layer of the sample has no visible cracks, no peeling area exceeding 5mm ², and the retention rate of the base fabric fracture strength is ≥ 80% (special purposes can be adjusted through negotiation).

2. Technical parameter requirements

The unified regulation of testing conditions by standards is the key to ensuring comparability of results, and the core parameters are as follows:

1Number of workstations: 6 (customizable).

2 Test piece dimensions:125mmx37.5mm (3 latitudinal and 3 radial directions)

3fixturemaximumDistance:70±1mm

4fixtureminimumspacing：13±0.5mm

5Test speed:300 ± 10 CPM (adjustable from 100-400 CPM)

6Round trip:57±0.5mm

7Counter: Digital display0-999999(6digits)

3、 Testing methods and operational points

1. Testing principle

Fix the sample to the clamping device of the flexural testing machine, and achieve 180 ° repeated bending through eccentric wheel drive. After reaching the specified number of times, observe the coating layer status and test the remaining strength of the base fabric. Compare the initial performance to determine the flexural resistance level.

2. Key operational steps

sample preparationCut several samples along the warp and weft directions of the fabric to avoid sampling at the edges or defects. The edges of the samples should be sealed with adhesive to prevent yarn from scattering during testing.

State adjustmentPlace the sample in a standard environment for at least 24 hours to ensure that the material reaches environmental equilibrium (moisture absorption/moisture release stability).

Equipment CalibrationBefore testing, it is necessary to calibrate the bending angle (verify with a protractor that the deviation of 180 ° is ≤ 2 °) and frequency (count with a stopwatch, and the deviation of bending times within 1 minute is ≤ 5 times)

test processSet the number of bending times (usually 100000 times, special products can be specified in the contract), observe the status of the sample in real time after starting the equipment, and record the first number of damage times if there is cracking in the coating layer halfway.

result evaluation：

Appearance inspection: Use a 10x magnifying glass to observe whether there are cracks, bubbles, or peeling in the coating layer, and measure the peeling area.

Strength testing: Use a tensile testing machine to test the fracture strength of the bent sample and calculate the retention rate (retention rate=flexural strength/initial strength x 100%).

3. Common sources and control of errors

Improper edge sealing of the sample leads to loose yarn at the edges, and an adhesive compatible with the coating material (such as polyurethane) should be selected.

Uneven clamping force leads to sample displacement, and the clamping device needs to be adjusted to ensure that the centerline of the sample coincides with the bending axis.

Environmental temperature and humidity fluctuations require testing in a constant temperature and humidity laboratory, and avoid opening doors for ventilation during testing.

4、 Application and Implementation Significance of Standards

1. Industry application scenarios

quality controlProduction enterprises use it for raw material incoming inspection and finished product factory inspection. For example, waterproofing membranes need to pass 200000 times of bending without damage before leaving the factory.

Product DevelopmentOptimization of new coating fabric formula, determining the process by comparing the flexural resistance of different coating thicknesses and base fabric types.

Engineering selectionWhen selecting outdoor tents, inflatable boats, and other products, priority should be given to materials that can withstand bending times ≥ 150000 times to ensure their service life.

third-party testingQuality inspection agencies conduct product qualification assessments based on this standard, providing fair data for both trading parties.

2. Core differences from the old version (2003 version)

Added the indicator of "retention rate of base fabric fracture strength" to more comprehensively reflect the influence of flexibility on the overall performance of the material.

Refined the testing conditions for different types of coated fabrics (such as rubber coated fabrics that can use higher bending frequencies).

Clear requirements for sample edge sealing have been established, reducing testing errors.

Updated reference standards (such as GB/T 3923.1-2013 replacing the old version of tensile testing standards).

3. Key execution tips

The bending frequency should be adjusted according to the actual usage scenario of the product. For example, it is recommended to test 300000 times for frequently folded protective clothing fabrics, and 100000 times for static waterproof rolls.

The bonding strength between the coating layer and the base fabric is the key factor affecting the flexural resistance. If the bonding strength is insufficient (lower than the requirements of GB/T 14646 standard), the bonding process needs to be optimized first.

The test results need to report both the appearance status and strength retention rate, and passing a single indicator does not mean overall compliance.

5、 Summary and Prospect

As a testing standard for the flexural resistance of coated fabrics, GB/T12586-2017's core value lies in achieving quantitative evaluation of material properties through unified and scientific testing methods, providing technical support for industry quality improvement. In practical applications, enterprises need to strictly follow standard testing conditions and operating specifications, and set assessment indicators reasonably based on product usage; Meanwhile, with the development of new materials such as nanocoating and composite fabrics, it is recommended to pay attention to the revision dynamics of standards to ensure that testing methods keep pace with technological advancements.

In the future, this standard may further refine the requirements for flexural testing in special environments such as high temperature, low temperature, and humid heat, and increase the evaluation of the flexural performance of coating layers after aging to meet the needs of more application scenarios.

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