GB/T 4893.3-1985 Determination of dry heat resistance of furniture surface paint film GB/T4893.3-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of dry heat resistance of furniture surface paint film
Furniture-Assessment of surface resistance to dry heat
UDC 684.4 : 667
GB 4893.3—85
This standard is applicable to the determination of dry heat resistance of paint film on wooden furniture and other wooden furniture parts. Use a container containing medium and place it on the surface of the sample at the specified temperature. After the specified time, take out the container and grade it according to the degree of damage to the paint film. 1 Instruments and materials
1.1 Copper test cup (see Appendix A).
1.2 Electric furnace.
1.3 Balance with a graduation value of 0.1g.
1.4 Crucible tongs.
1.5 Thermometer 0~200℃ mercury thermometer, with a graduation value of 1℃. The specification of the heat insulation pad is not less than 100mm×100mm×10mm wooden board. 1.6F
Heating medium Mineral oil with a ignition point of not less than 250℃. 1.8
Observation box (see Appendix B).
2Specimen
Specification is 250mm×200mm.
2.2The specimen shall be stored for at least 10 days after coating and completely dried before testing. 2.3The surface of the specimen shall be flat and the paint film shall be free of defects such as scratches and bubbles. 2.4When sending samples, a test report shall be attached, including the name of the coating, a brief coating process, production time, etc. 3Test conditions,
3.1The test room temperature is 20±2℃ and the relative humidity is 60%~70%. 3.2The test temperature shall be based on the product standard or the agreement between the supply and demand parties. Recommended test temperatures: 70℃, 80℃, 90℃, 100℃, 120℃. 4 Test steps
4.1 Choose three test areas on the sample, each with a diameter of 50mm. The distance between the center of the test area and the edge of the sample should be no less than 40mm, and the distance between the centers of the three test areas should be no less than 65mm. 4.2 After the test area is determined, mark it. Before the test, the test data of color, gloss and film appearance must be recorded according to the following requirements:
The selected comparison area should be consistent with the color of the tested area. Color
Measure the gloss value of the tested area with a photoelectric gloss meter. Gloss
Visually, there should be no obvious defects in the tested area. Appearance
Check the bottom of the copper test cup. There should be no surface damage and adhesion, and then inject 100±1g of mineral oil. 4.3
Place the copper test cup on an electric furnace and heat it until the oil temperature exceeds the specified temperature by 10℃ (safety must be ensured during the heating process). Use crucible tongs to place the test cup on an insulating pad. Let the oil temperature drop slightly and stir the mineral oil continuously to make the temperature evenly distributed. Issued by the National Bureau of Standards on February 1, 1985
Implemented on April 10, 1985
GB 4893.3--85
4.5When the oil temperature in the copper test cup reaches the specified temperature, move the test cup to the test area and let it stand for 15 minutes. 4.6After the specified time is reached, remove the test cup, wipe the test area with filter paper, mark the test temperature, and let it stand for 16 to 24 hours. Note: If an electric heating cup is used, it should comply with the provisions of 1.1: its heating effect is the same as that of the copper test cup containing oil. 4.7 Wipe the test area with filter paper again and inspect according to the requirements of 4.8. Place the test area on the sample in the observation box at the center of 550mm from the back, with a visual distance of 0.5 to 1m, and check the imprint and 4.8
tarnish.
Then place the sample under natural light indoors, check whether the test area has discoloration, bubbling, etc., and compare and analyze with the data of 4.2 test. For example:
The color of the visual test area and the comparison area is different, which is discoloration; the measured value is 5 to 10% lower than the original measured value, which is slight tarnish; the tiny bubbles visible on the surfaceWww.bzxZ.net
are bubbling of the paint film. 5
Evaluation of test results and test report
The classification standards are shown in the table below.
No test cup marks found
Intermittent slight marks and slight discoloration
Almost complete ring marks or circle marks and slight discoloration Obvious ring marks or circle marks, discoloration
Severe ring marks or circle marks, discoloration or blistering
Three testers must evaluate each test area separately, and take the majority of the same values ​​as the evaluation results. 5.2
5.3The three test areas on the same sample must be evaluated separately, and the consistent evaluation values ​​of the two test areas shall be the final test values. If inconsistent, the test can be repeated once.
5.4The test report shall include the following contents:
Test date,
The name of the coating of the sample and a brief coating process, the storage date of the sample after coating,
Test time and test results, etc.
GB 4893.3—85
Appendix
(Supplement)
The copper test cup is used to determine the dry heat resistance of the paint film on the surface of wooden furniture. It is a container for holding heating medium. A.1 Material and surface requirements
A.1.1 The material is made of ZH62 brass.
A.1.2 The surface of the bottom ring of the cup must be finely processed with a finish of V6. A.1.3 The surface must be polished before electroplating. There must be no defects such as machining marks, burrs, corrosion marks, scratches, sand holes, etc. The surface after electroplating must be polished.
A.1.4 The weight of the copper test cup is 440±25g.
A.2 Dimensions
The dimensions of the copper test cup are shown in the figure below.
50 ± 0:1
44±0.1
040 ±0.1
Schematic diagram of copper test cup
GB 4893.3-85
(Supplement)
The observation box is used to observe the marks and tarnishing of the test area on the test piece. B.1 Structure and materials
The box body is made of 15mm thick solid wood or particle board. B.1.2 A hole with a diameter of 25mm is opened on the inclined surface of the box body. A 60W white frosted bulb is fixed above the hole by a hinge through the lamp holder plate. The angle of light projected onto the sample is 30°~60°. B.1.3 The inner wall is painted with black matte paint.
B.2 Dimensions
The dimensions of the observation box are shown in the figure below.
Additional instructions:
60W white frosted bulb
25mm hole
Observation area
Observation box diagram
Observation point
This standard is proposed by the Ministry of Light Industry of the People's Republic of China and is technically managed by Shanghai Furniture Research Institute. This standard is drafted by Shanghai Furniture Research Institute. The main drafter of this standard is Xiao Zhengming.
This standard is formulated with reference to British Standard BS3962: Part 3: 1980 "Test methods for surface finishing of wooden furniture - surface resistance to dry heat test".
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