Q1. Please summarize the main equipments used in the colorfastness tests
(rubbing, washing, light, perspiration), and simply introduce their usages.
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In the colorfastness test to rubbing, the main equipment is crockmeter with a reciprocating rubbing motion (moving back and forth) simulating the action of human finger and forearm and providing a downward force 9N. It is used for testing the transference of color from the surface of one material to another by either wet or dry rubbing. In dry rubbing, a specimen flat is placed on the crockmeter base, covered and fastened by the specimen holder.
Evenly run the crank 10 turns in 10 seconds, and remove the white square cloth, condition and evaluate staining. For wet rubbing, thoroughly wet out a white square cloth with distilled water and continue the testing as directed for dry test.
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In the colorfastness test to washing, the main equipment is laundry machine, which is able to rotate closed canisters in a water bath of controlled temperature. It is used to imitate the condition of hand or home launderings. In colorfastness to washing, the multifiber fabric is attached to specimen by sewing or stapling. Set the laundry machine temperature, and put a specimen into each canister with detergent and stainless steel balls. Fasten the canisters on the rotor of machine, and start the machine. Then, collect the specimens, dry them and assess the color change and staining.
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In the colorfastness test to light, Xenon-arc lamp fading apparatus is the main equipment with the controlled temperature and humidity chamber. The spectral distribution of xenonarc lamp filtered with the specified glass is very close to that of average or typical daylight in UV part, which can demonstrate the normal condition of cloth in daylight. In colorfastness to light, the specimen is mounted and standard on a white cardboard as backing. Place the unit in an exposure frame and mount the frame on the specimen rack.
Then, expose the specimens and standards to the desired amount of radiant energy.
Assess the color change and classify the lightfastness by comparison to standards.
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In the colorfastness test to perspiration, perspiration tester is the main equipment which provides standard force about 4.54 kg on fabrics between plastic plates by adding weight or adjusting screw, and is locked with a set screw in horizontal or vertical way. The plastic plate is used to grip the specimen and the pressure block is to transfer the force to all specimen and keep constant pressure by a spring function without loading weight. In perspiration, a multifiber fabric is attached to the specimen by sewing, and soak the specimen in fresh perspiration solution to ensure complete wetting. Each specimen is placed between plastic plates in the perspiration tester and put the loaded tester in an oven at 38 oC for 6 hours. Then, evaluate the color change and staining.
