Determination of the abrasion resistance of fabrics using the Martindale method

1. Reference Standard:

GB/T 21196 Determination of Abrasion Resistance of Martindale Fabrics (This standard is divided into four parts, namely Martindale Abrasion Tester, Sample Damage Determination of Mass Loss, Appearance Change Evaluation)

2. Test Equipment:

Martindale Abrasion Tester

3. Test Principle:

The substance to be tested is installed in the upper sample holder and rubbed against the abrasive installed on the grinding table. The friction trajectory is a Lissajous figure. After setting the number of rubs, make relevant records, observations and calculations.

4. The composition of the test instrument:
The whole instrument includes the following main parts: sample mounting plate, sample mounting, grinding table, transmission device, counter.
The transmission device moves the guide plate of the sample holder. The sleeve on the guide plate of the sample holder connects seamlessly to the sample holder. The friction to be testeds sample is installed in the sample holder and performs a frictional movement with the fabric or abrasive installed on the grinding table. A counter records the number of rubs. The standard specifies that one revolution of the two outer drive wheels in the Martindale instrument transmission be recorded as one friction.
The sample fastener consists of four parts from top to bottom: the fastener pin shank, fastener sleeve, fastener insert, and compression nut. The figure is a schematic diagram of the sample fixture (excluding the pin shaft portion of the fixture).

1. Sleeve
2. Compression nut
3. Insert

1 5. The side view of the sleeve

5. The grinding table consists of the grinding table, the clamping ring and the holder for fixing the clamping ring. The mass is (2.5 ± 0.5) kg and the diameter is (120 ± 10) mm pressure hammer assembly. The function of the pressure hammer is to avoid surface wrinkles and unevenness caused by the movement of the fabric when installing the abrasive. After the abrasive is fixed, the pressure hammer is removed for later installation.

6. Introduction of auxiliary materials:
(1) Abrasive: The function of abrasive is to rub against the test fabric above. In GB/T 21196, the abrasive is woven plain wool cloth with a diameter or side length of at least 140 mm. The abrasive of the coated fabric adopts NO.600 water sandpaper.
(2) Felt: It is placed on the grinding table along with the abrasive, and there is a circular woven wool backing under the abrasive. The mass per unit area is 750 ± 50 g / m2, the thickness is 2.5 ± 0.5 / mm, and the size is 1400 + 5 mm.
(3) Foamed plastics: when the mass per unit area of ​​the substance is less than 500 g/m2, put it in the test stand and use it aAs a pad to test the fabric. The size is 38.0+50mm.

7. Installation sample, abrasive and auxiliary material
The sample is placed in the sample holder. First, put the sample in the center on the compression nut of the sample holder, with the friction surface of the sample facing down, and the size of the sample is 38.0 + 50mm. When the weight of the sample is less than 500 g/m2, place the foam pad on the sample. Place the insert in the union nut and insert thePlace the specimen holder connection and tighten.
During the abrasive installation process, first put the felt on the grinding table, and then put the abrasive on the felt. When placing the abrasive, the warp and weft threads of the abrasive material should be parallel to the edge of the instrument table. When installing, press the heavy hammer against the felt and abrasive on the grinding table, tighten the clamping ring and remove the onpressure heavy hammer after confirmation.

8. Test and assessment of fabric abrasion resistance:
(1) Determination of sample damage - wearing times
Apply different friction loads to different types of fabric:
a ) Workwear, upholstery fabrics, bedding, industrial fabrics: ( 795±7)g
b) Clothing and home textiles: (595±7)g
c) Wear coated fabrics: (198±2 )g
After applying the test sample, abrasives and excipients. Start the instrument and continuously rub the sample until the preset number of rubs is reached. During the rubbing process, the sample should be observed at an inspection interval to prevent the sample from being worn out before the set number of rubs. When the following situations occur in the sample as the end point of friction, the sample is broken:
- At least two independent yarns in the woven fabric are completely broken;
--One yarn in the knitted fabric is bornsmoking Causes a hole in the appearance;
——The surface pile of the pile or cut pile fabric is worn down to the ground or the tufts fall off;
——The hole caused by friction on the fleece fabric, its diameter At least 0.5mm - The coating part of the coated fabric is destroyed to expose the base fabric or the flake coating falls off.
Measure the total number of rubs when each sample is damaged and use the accumulated number of rubs before the sample is damaged as the number of abrasions. If desired, calculate the mean and confidence interval for the mean wearing times.
(2) Measurement of mass loss - abrasion resistance index
According to the number of rubs when the sample is damaged, the mass loss of the tested substance is measured at a certain number of rubs, as shown in the following table:

After completing the test according to the number of frictions in the table, draw a graphk according to the average mass loss corresponding to each number of frictions and calculate the wear resistance index according to the formula.
Ai=n/△m
Ai——abrasion resistance index, the unit is times per milligram (times/mg)
n——total friction times, the unit is times
△ m——The mass loss of the sample under the total friction times, in milligrams (mg)
(3) Evaluation of appearance changes
Perform the wear test with the agreed number of friction times, and evaluate the area of ​​the friction area of the sample Changes, such as discoloration, lint, pilling, etc. on the surface of the sample. Determine the number of rubs for each sample to achieve the specified surface change, or evaluate the appearance change of the sample after the agreed number of rubs.

9. Remarks:
(1) Determination of the inspection interval (the number of rubs): The inspection interval is set to prevent the wnapping of the fabric exceeds the predetermined number of times . In the sample fracture test, avoid wearing out the sample so that the number of abrasions cannot be determined. When evaluating the appearance change, set the inspection interval to avoid missing the friction times that cause the surface change of the sample.
(2) The test sample shall be placed in a relaxed state on a smooth, air-ventilated surface and placed at standard atmospheric pressure for at least 18 hours. When sampling, the distance from the edge of the fabric should be at least 100mm, and a sufficient number of samples (usually a minimum of 3 pieces) should be cut from the entire laboratory sample, and all information about the fabric should be included as much as possible.

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