This method is mainly applicable to the 45° angle specular gloss of metal composite paper and paperboard such as aluminum foil paper, vacuum aluminum-plated paper, etc. GB 8941.2-1988 Paper and paperboard specular gloss determination method 45° angle determination method GB8941.2-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Measurement of specular gloss of paper and paperboard
45° angle measurement
Paper and board--Measurement of specular gloss (45°)GB 8941.2—88
This standard specifies the method for measuring the specular gloss of metal composite paper and paperboard using a 45° angle gloss meter. This standard refers to the international standard ISO26761975 "Measurement of specular gloss at 45° angle on anodized surfaces of aluminum and its alloys". 1 Scope of application
This method is mainly applicable to the 45° angle specular gloss of metal composite paper and paperboard such as aluminum foil paper and vacuum aluminum-plated paper. 2 Definition
2.1 Gloss The property of directional selective reflection on the surface of an object, which determines the degree of strong reflected light or mirror image of the object that can be seen on the surface of the object.
2.2 Specular gloss The ratio of the luminous flux reflected from the sample surface into the specified aperture in the direction of specular reflection (regular reflection) to the luminous flux reflected from the standard mirror under the same conditions. Expressed as a percentage. 3 Instrument
3.1 Optical system of the instrument
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45° angle gloss test head optical system diagram 1-reflection surface; 2 photocell; 3-receiving light bar hole, diameter 1.5mm; 4-frosted bulb; 5-brass lampshade; 6-incident light bar hole, diameter 1.5mm; 7-lens; 8-total reflection prism
The light emitted by the 3W frosted bulb powered by a stable power supply is shone on a light bar with an aperture of 1.5mm, and the light bar is at the focal position of the lens. The parallel light beam generated is projected onto the sample surface and reflected. The incident angle and reflection angle are both 45±0.5°. The reflected light is focused by the second lens, forming an image of the incident light bar hole on the receiving light bar hole, and the light beam is projected onto the photocell. The lens adopts an achromatic doublet cemented lens, and its relative aperture shall not exceed f/3. The distance between the photocell and the receiving light bar should be far enough, because the diameter of the light spot is about 19mm. Approved by the Ministry of Light Industry of the People's Republic of China on April 12, 1988 and implemented on August 1, 1988
GB8941.2--88
The sample pressing plate is used for vacuum adsorption of the sample. When a piece of plastic film with uniform thickness (such as 0.08mm optical grade polyester film) is positioned with a suction plate, the image formed on the light receiving device window and the image formed on the standard plate cannot be measured in position and size. 3.2 Gloss Standard
The standard surface is the hypotenuse surface of a 45° right-angle prism with total internal reflection. This surface is lined on an anodized aluminum plate. The size of the prism is 25mm×25mm×35.3mm, and it is made of hard crown glass; the refractive index is within the range of 1.50~1.52. It absorbs 1.5%~2.0% of visible light within a distance of 25mm. Its mirror reflectivity factor should be between 80%~90%. This standard should be calibrated regularly by the superior metrology department. 3.3 Black cylinder with black velvet lining.
4 Preparation of samples
4.1 Sampling and processing shall be carried out in accordance with the provisions of GB450 "Taking of Paper and Paperboard Samples", and testing shall be carried out under standard conditions. 4.2 Cut 10 100mm×100mm test pieces from the extracted paper sheets, avoid defective parts, keep them clean, and do not touch the test surface with your hands.
5 Calibration of the instrument
5.1 Turn on the power according to the instrument manual. After preheating, place the gloss standard plate on the measuring hole and adjust the reading to the calibration value of the standard plate. 5.2 Replace the black tube and adjust the instrument reading to zero, then place the standard plate and adjust the instrument reading accurately to the calibration value. 6 Test procedure
Insert a sample each time to read the gloss value, and measure each sample in both the vertical and horizontal directions. Measure 10 times in the vertical and horizontal directions respectively, and express the results as the vertical and horizontal average values ​​and coefficients of variation. To ensure the test accuracy, during long-term continuous testing, the instrument should be calibrated regularly with the standard plate and calibrated again after the test.
7 Accuracy
When testing uniform samples with instruments that strictly comply with this method, the reproducibility of the test results is within 2 gloss units. 8 Test report
Number of this standard:
Marking and description of the sample;
Gloss value of the sample;
Report the variation system of the test results as needed; Any test conditions that deviate from this standard.
Additional instructions:
This standard is under the jurisdiction of the Paper Industry Research Institute of the Ministry of Light Industry of the People's Republic of China. This standard was drafted by Tianjin Paper Research Institute. 450
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