This standard specifies three methods for measuring the specular gloss of plastics at 20°, 45° and 60° angles. This standard is applicable to the measurement of specular gloss of plastics. The 20° angle is used for high-gloss plastics, the 45° angle is mainly used for low-gloss plastics, and the 60° angle is mainly used for medium-gloss plastics. The comparison of specular gloss is only applicable to the same type of plastics using the same method. GB 8807-1988 Test method for specular gloss of plastics GB8807-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for specular gloss of plastics
Test method for specular gloss of plasticsSubject content and scope of application
This standard specifies three methods for measuring the specular gloss of plastics at 20°, 45° and 60° angles. UDC 678.5/7
GB 8807-88
This standard applies to the measurement of specular gloss of plastics. The 20° angle is used for high-gloss plastics, the 45° angle is mainly used for low-gloss plastics, and the 60° angle is mainly used for medium-gloss plastics. The comparison of specular gloss is only applicable to the same type of plastics using the same method. 2 Reference standards
GB2918 Standard environment for state adjustment and testing of plastic specimensGB3978 Standard lighting and lighting observation conditions3 Terminology
3.1 Specular gloss
The ratio of the specular reflectivity of the specimen to the specular reflectivity of the reference surface under the same conditions at a specified incident angle. When expressed as a percentage, the percentage sign can be omitted and expressed in gloss units. 3.2 Specular reflectivity
The ratio of the specular reflected luminous flux to the incident luminous flux. 4 Test instrument and its requirements
4.1 This test uses a specular gloss meter, and its working principle is shown in Figure 1. Approved by the Ministry of Light Industry of the People's Republic of China on February 13, 1988 284
Implemented on July 1, 1988
GB8807-88
Figure 1 Schematic diagram of the optical path of the specular gloss meter
1-Receiver; 2-Receiver aperture; 3-Viewing function correction filter, 4-Receiving lens; 5-Incident lens; 6-Light source aperture; 7-Condenser lens; 8-Light source spectrum correction filter; 9-Light source 4.1.1 Geometric conditions
4.1.1.1 The optical axes of the incident light beam and the specular reflection light beam are located in the same plane on both sides of the normal line and form equal angles with the normal line. 4.1.1.2 Reception should be in the direction of specular reflection. 4.1.1.3 When a reference plate is placed at the sample position, the light source image should be formed at the center of the receiver aperture. 4.1.1.4 The geometric angles and tolerances of the light source aperture and the receiver aperture shall comply with the requirements of Table 1. Table 1
Incident angle
20.0±0.1
45.0±0.1
60.0±0.1
In the measuring plane
0.75±0.25
0.75±0.25
Light source aperture
In the vertical measuring plane
Not more than 3.0
Not more than 3.0
4.1.1.5In 4 .1.1 The beam should not have halo within the solid angle specified in Receiver aperture
In the measuring plane
1.80±0.05
In the vertical measuring plane
10.0±0.2
11.7±0.2
4.1.1.6: The light source should meet the spectral conditions of standard illuminant C or Ds5 in GB3978; the spectral response of the receiver should reproduce the standard light efficiency function Va).
4.1.2 Accuracy
One gloss unit.
4.1.3 Repeatability
Not more than one gloss unit.
4.1.4 Reproducibility
Not more than three gloss units.
4.2 Fixing device for film samples
Any film must be fixed on this device that can keep it flat and without stretching. 4.2.1 Vacuum plate (see Figure 2): connected to a vacuum pump or vacuum conduit through a rubber tube, with a valve to limit its vacuum degree, and the vacuum degree is measured by a vacuum gauge.
GB 8807-88
Figure 2 Vacuum plate for film fixing
1---oxidized flat plate, 2--0-ring; 3-vacuum base; 4-vacuum hose connector 4.2.2 Flat plate with double-sided pressure-sensitive tape (see Figure 3): To ensure that the sample is flat, the film should not be stretched before the pressure-sensitive tape sticks to the film. When the pressure-sensitive tape loses its stickiness, it should be replaced in time. Figure 3 Flat plate for film fixing with double-sided pressure-sensitive tape 1 Double-sided pressure-sensitive tape; 2--sample; 3--optically flat plate 4.3 Backing for transparent samplebzxz.net
Select a black base plate, preferably a black cavity, which must be placed behind the transparent sample. 4.4 Standard plate
4.4.1 First-level working standard plate
Use a highly polished flat black glass plate. For 20° and 60° angles, use a black glass plate with a refractive index of 1.567, and the gloss value is specified as 100; for 45° angle, use a black glass plate with a refractive index of 1.540, and the gloss value is specified as 55.9.4.4.2 Second-level working standard plate
Use hard, flat, and uniform-surfaced porcelain, etc., but must be calibrated by a mirror gloss meter in accordance with Article 4.1.1. 4.4.3 Use and maintenance of standard plates
Standard plates must be kept clean and their surfaces must not be damaged. When using, hold them by the edge and never touch the surface. When cleaning, do not wipe with a towel, hard brush or paper, etc., and use a general optical lens cleaning fluid to clean the surface. When not in use, place them in a sealed and dry container. In addition, standard plates must be inspected and recalibrated regularly.
5 Samples and their preparation
GB 8807--88
5.1 The surface of the sample should be smooth and flat, without dirt, scratches and other defects. The samples should be cut from different parts, and their size should be 100mm×100mm. There should be no less than 3 samples in each group in the test.
5.2 Sample state adjustment and test environment
Carry out at normal temperature and humidity in accordance with GB2918. 6 Test steps
The specular gloss meter must be calibrated during the test. First, calibrate the primary working standard plate, and then check the specular gloss of the secondary working standard plate. If the measured reading of the secondary working standard plate exceeds its nominal value by one gloss unit, then the specular gloss meter must be adjusted by the manufacturer before it can be used.
Diffusion correction
It is only used when the manufacturer and the user agree. When making this correction, the incident light beam illuminates the sample at an angle of 45° and is received at an angle of 0°. The measured reflection value is multiplied by the percentage factor (Table 2) to obtain the gloss correction value. Table 2
20° angle
45° angle
60° angle
8 Calculation and expression of results
8.1 The measurement results are expressed as the arithmetic mean of a group of samples, accurate to 0.1 gloss unit. 8.2 The standard deviation value S is calculated as follows:
Where: X-the measured value of each sample;
x-the arithmetic mean of the measurement results of a group of samples; n
The number of samples measured.
9 Test report
The test report shall include the following contents:
Plastic name, specification, manufacturer,
Surface state of the sample;
Sample preparation method;
Film sample fixing device;
Method used (20° angle, 45° angle or 60° angle); state adjustment and test environment;
Specular gloss standard plate;
Specular gloss arithmetic mean;
Give standard deviation when necessary;
E(X -x)2
Percentage factor
Test date and personnel.
Additional remarks:
8807-88
This standard is proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the Plastic Processing and Applied Science Research Institute of the Ministry of Light Industry. This standard is drafted by the Plastic Processing and Applied Science Research Institute of the Ministry of Light Industry. This standard refers to the American Society for Testing and Materials standard ASTMD2457-77 "Standard Test Method for Specular Gloss of Plastic Film" and ASTMD523-80 "Standard Test Method for Specular Gloss".
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