This part is developed in accordance with the rules given in GB/T 1.1-2009.
This Part replaces GB/T 3903.41-2008 Footwear - Test methods for uppers and lining - Flex resistance, and the following main technical changes have been made with respect to GB/T 3903.41-2008:
——The normative references are modified (see Clause 2, Clause 2 of Edition 2008);
——The term “surface” is added (see 3.2);
——The “General” part is added (see Clause 4);
——The requirements for "wet tests and cold tests" in "sampling and conditioning" are added (see 6.3 and 6.4);
——The number of tests for taking the test specimen from the machine is modified (see 7.2.6; 6.2.7 of Edition 2008);
——The requirements for record content of materials with coating on the surface after testing is modified (see 7.2.8; 6.2.9 of Edition 2008);
——The requirement for recording “Labeling” in the test report is added (see Clause 8).
This part, by means of translation, is identical to ISO 17694: 2016 Footwear - Test methods for uppers and lining - Flex resistance.
The Chinese documents identical to the normative international documents given in this part are as follows:
——GB/T 6682-2008 Water for analytical laboratory use - Specification and test methods (ISO 3696:1987, MOD);
——GB/T 22049-2019 Footwear - Standard atmospheres for conditioning and testing of footwear and components for footwear (ISO 18454: 2018, IDT);
——GB/T 22050-2008 Footwear - Sampling location, preparation and duration of conditioning of samples and test pieces (ISO 17709: 2004, IDT);
——QB/T 2714-2005 Leather - Physical and mechanical tests - Determination of flex resistance (ISO 5402: 2002, MOD).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This part was proposed by China National Light Industry Council.
This part is under the jurisdiction of SAC/TC 305 National Technical Committee on Footwear of Standardization Administration of China.
The previous edition replaced by this part is as follows:
——GB/T 3903.41-2008.
Footwear - Test methods for uppers and lining - Flex resistance
1 Scope
This part of GB/T 3903 specifies a test method for determining the flex resistance of uppers and linings in order to assess the suitability for the end use.
This part is applicable to uppers and linings made of various materials.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696 Water for analytical laboratory use - Specification and test methods
ISO 5402-1:2011 Leather - Determination of flex resistance - Part 1: Flexometer method
ISO 17709 Footwear - Sampling location, preparation and duration of conditioning of samples and test pieces
ISO 18454 Footwear - Standard atmospheres for conditioning and testing of footwear and components for footwear
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flex resistance
resistance of a material to crack or otherwise fail at flexing creases
3.2
surface
visible site of the material during the use at the shoe
Note: The visible site of the material can be by upper the grain site of the leather or the coated site of a coated textile, by lining the site of the material visible from the inside of the shoe.
4 General
Test specimens are cut from a shoe vamp or from material for shoes, folded and inserted in the test machine. The test simulates the damage caused by the inward folding of the vamp of the upper, but does not readily simulate damage occurring on outward folds. It is carried out humid, dry or in a cold climate.
5 Test apparatus and materials
The following apparatus and materials shall be used.
5.1 Test machine, in accordance with ISO 5402-1: 2011 (4.1) including the following:
5.1.1 At least four pairs of clamps. The upper clamp consists of a pair of flat plates, as shown in Figure 1. The lower clamp is fixed and lies in the same vertical plane as the upper clamp.
Dimensions in millimeters
Keys:
1——flexing angle 22°30’ ± 0°30’;
2——clamp tightening screw;
3——2 mm fillet radius;
4——horizontal axis.
Figure 1 Upper clamp dimensions
5.1.2 The upper clamp, which may perform a reciprocating action, with an flexing angle of 22°30’ ± 0°30’. The speed of oscillation shall be (100 ± 5) r/min. The distance between the upper and lower clamp, when the upper clamp is in the horizontal position, shall be (25 ± 1) mm.
5.1.3 Counter, for which the total number of cycles shall be recorded.
5.2 Press knife, (70 ± 1) mm × (45 ± 1) mm or similar tools for cutting test specimens.
5.3 Optical magnifier, with a magnification of approximately four to six times.
5.4 For wetting test specimens, the following apparatus and materials are required.
5.4.1 Glass dish, with a minimum diameter of 100 mm and depth of 25 mm.
5.4.2 Distilled or deionized water, complying with the requirements for Grade 3 of ISO 3696.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General
5 Test apparatus and materials
6 Sampling and conditioning
7 Test method
8 Test report
