This standard specifies the determination method and evaluation of the degree of powdering of paint coatings. This standard is applicable to the determination of the degree of powdering of paint coatings on various substrates during atmospheric or artificial accelerated aging and use. GB/T 14826-1993 Determination method and evaluation of the degree of powdering of paint coatings GB/T14826-1993 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determining and evaluating degree ofchalking of paint coats
GB/T14826--93
Approved and issued by the State Administration of Technical Supervision
Approved on December 30, 1993
Implementation on October 1, 1994
1 Subject content and scope of application
This standard specifies the determination method and evaluation of the degree ofchalking of paint coats. This standard is applicable to the determination of the degree ofchalking of paint coatings on various substrates during atmospheric or artificial accelerated aging and use.
2 Reference standards
GB1765 Method for preparing paint films for determining resistance to moisture and heat, salt spray and weathering (artificial acceleration) GB 1767 Method for determining weathering resistance of paint films
3 Samples
The samples for atmospheric sudden exposure weathering resistance test are prepared in accordance with the provisions of GB1767. Unless otherwise specified, their dimensions are 150mm×250mm×0.8~1mmc
The samples for artificial accelerated weathering resistance test are prepared in accordance with the provisions of GB1765. Unless otherwise specified, their dimensions are 70mm×150mm×0.8~1mmc
4 Test methodsWww.bzxZ.net
The test methods include the powdering tester method and the manual test method for color paint coatings. 4.1 Method A Powdering Tester Method
4.1.1 Principle
An instrument that uses a crankshaft rotating mechanism to drive a 16mm metal friction head with a swab cloth on a ring to make linear reciprocating friction movements on the coating surface. The powder particles formed by the powdering of the coating adhere to the swab cloth due to the friction of the friction head. The powdering degree of the paint coating is evaluated according to the degree of adhesion of the pigment particles on the swab cloth. 4.1.2 Paint Coating Powdering Tester
The structure is shown in the figure.
Schematic diagram of the paint coating powdering tester 1--friction head; 2-set; 3-friction head ball nut; 4-weight block; 5-reciprocating flat iron; 6-automatic stop mechanism; 7-power switch; 8-start button; 9-support column handle; 10-support column; 11-right clamping knob; 12-sample table lateral shift handle; 13 sample table; 14-left clamping knob 700
4.1.2.1 The instrument is equipped with an automatic stop mechanism (6) that can reciprocate 10 times and a manual switch and button that can arbitrarily control the number of reciprocating times.
4.1.2.2 The crankshaft of the instrument rotates 60 times/min, driving the friction head (1) to a stroke of 65±5mm. The support column handle (9) controls the support column (10) to raise and lower the friction head at will. 4.1.2.3 According to the test requirements, a weight block (4) can be installed on the reciprocating fan iron (5) so that the friction head forms a 9N weight on the coating.
4.1.2.4 The size of the instrument sample table (13) is 150mm×200mm. The clamping knobs (11, 14) on the left and right of the rotating table can clamp the test sample. When the sample length is less than 150mm, an accessory clamping plate can be added. 4.1.2.5 The friction head is equipped with a movable ring (2), which can easily put a desizing and fine bleaching muslin cloth with a size of 45mm×45mm on the friction head. Black cloth is used as the wiping cloth for white and light-colored paint coatings, and white cloth is used as the wiping cloth for other colors.
4.1.3 Test steps
4.1.3.1 Rotate the support column handle (9), lift the reciprocating flat iron (5), and add or not add a weight block according to the test requirements. 4.1.3.2 Place the sample plate on the sample table (13) so that the coating film in the middle of the sample is evenly hooked under the friction head. Turn the left and right clamping knobs (11, 14) to clamp the sample. If necessary, add an accessory clamp to fix the sample. 4.1.3.3 Pad or stick a piece of suede artificial leather with a thickness of about 1mm and the same area as the bottom of the friction head on the friction head (1), with the suede side facing down. Place the wiping cloth on the ring (2) and close to the friction head with suede artificial leather. Push up the ring to clamp the wiping cloth. 4.1.3.4 Rotate the support column handle, put down the flat iron, press the power switch (7) to turn on the power, and then press the start button (8). The instrument starts to work. After the crank rotates one circle, release the button. The flat iron automatically reciprocates 10 times and then stops. If an emergency shutdown is required due to special circumstances, the power switch (7) should be turned off immediately. 4.1.3.5 After the reciprocating motion stops for 10 times, rotate the support column handle, lift the flat iron, push down the ring on the friction head, and remove the wiping cloth.
4.1.3.6 Observe the degree of adhesion of the wiping cloth to the pigment particles, and evaluate the chalking level by comparing with the standard photo. Only one test is conducted on each sample.
4.1.3.7 In special circumstances, if the evaluation and grading are still unclear, a sample can be tested for the second time. At this time, the sample table lateral shift handle (12) in front of the sample table can be pinched, and the sample table (13) can be moved by slightly pushing or pulling to change the friction position on the sample. After changing the wiping cloth, the chalking degree at different positions can be measured. 4.2 Method B Manual Determination Method
4.2.1 Method A: Wrap the index finger with a desized and finely bleached plain muslin cloth as a wiping cloth. Use a black wiping cloth for white and light-colored paint coatings and a white wiping cloth for other colors. Then press the cloth on the coating film with force according to the test requirements and rotate it 180°. The cloth wrapped around the index finger will also rotate with it. Remove the cloth and compare the degree of pigment particles adhering to the cloth with the standard photo to evaluate the grade.
4.2.2 Method B: Use a clean index finger to rub the coating film of the sample to be tested back and forth twice according to the test requirements. The distance of the scratch is 5~7cm. Then evaluate the grade according to the degree of pigment particles adhering to the finger and compare it with the standard photo. 5 Evaluation
Both the instrument and the finger measurement method evaluate the grade by comparing the degree of pigment particles adhering to the cloth or finger with the standard photo. The degree of powdering of the coating is divided into six grades. 701
No powdering
Very light
China and other countries
The instrument pressurizes the weight or wipes the sample with fingers, and the rag or fingers are just visible with trace pigment particles
The instrument pressurizes the weight or wipes the sample with fingers, and the rag or fingers are sticky with a small amount of pigment particles
The instrument pressurizes the weight or wipes the sample with fingers, and the rag or fingers are sticky with more pigment particles
The instrument does not pressurize the weight or wipes the sample with fingers lightly, and the rag or fingers are sticky with a lot of pigment particles
The instrument does not pressurize the weight or wipes the sample with fingers lightly, and the rag or fingers are full of pigment particles or the test plate appears exposed Note: 1) The standard photos here should be provided by the Guangzhou Institute of Synthetic Materials, Ministry of Chemical Industry. Record the powdering level of the two samples of the atmospheric exposure weathering test separately. Standard photo 1)
Record the powdering grade of the reference sample of the artificial accelerated weathering test separately. And the results of the two samples with the same powdering grade are the test results.
Test report
The test report should include the following contents:
a. Type and name of the test sample.
b. Indicate whether this national standard is adopted.
C. Test method: powdering tester method or manual determination method (indicate whether method A or method B is used). d. The degree and grade of powdering of each test plate and the test results. e. Test date and tester.
Additional remarks:
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Paints and Pigments. This standard is drafted by the Institute of Synthetic Materials of the Ministry of Chemical Industry. The main drafter of this standard is Li Yanming.
Method 4.2.1A of this standard refers to the American Society for Testing and Materials standard ASTM D659 "Evaluation of the degree of powdering of exterior paints".
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