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GB/T 22638 comprises the following 10 parts under the general title Test methods for aluminium and aluminium alloy foils:
——Part 1: Determination of thickness;
——Part 2: Determination of pinhole;
——Part 3: Determination of stickiness;
——Part 4: Determination of surface wetting tension;
——Part 5: Determination of wettability;
——Part 6: Determination of direct current resistance;
——Part 7: Determination of heat seal strength;
——Part 8: Determination of cube texture content;
——Part 9: Determination of hydrophilic property;
——Part 10: Determination of mass per unit area (surface density) of coatings.
This is Part 10 of GB/T 22638.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 22638.10-2008 Test methods for aluminium and aluminium alloy foils—Part 10: Determination of mass per unit area (surface density) of coatings. The following main technical changes have been made with respect to GB/T 22638.10-2008:
——Some normative references are added;
——The principles of maleic acid method are deleted;
——The maleic acid method and required reagents and apparatus are deleted;
——The temperature requirements of muffle furnace are modified;
——The temperature fluctuation of the oven is modified;
——The quantitative standard circular specimen sampler with a sample area of 100 cm2 is added; the area deviation of the specimen is modified;
——The specimen requirements are modified;
——The temperature ranges of muffle furnace and oven are deleted in concentrated sulfuric acid method;
——The temperature ranges of muffle furnace and oven are deleted in the high-temperature baking method.
This part was proposed by China Nonferrous Metals Industry Association.
This part is under the jurisdiction of SAC/TC 243 National Technical Committee on Nonferrous Metals of Standardization Administration of China.
The previous edition of this part is as follows:
GB/T 22638.10-2008.
Test methods for aluminium and aluminium alloy foils—Part 10: Determination of mass per unit area (surface density) of coatings
1 Scope
This part of GB/T 22638 specifies the determination method for surface density of aluminum and aluminium alloy foil coatings.
This part is applicable to the determination for surface density of coated aluminium and aluminium alloy foils.
The high-temperature baking method specified in this part is applicable to the arbitration determination for surface density of the coating.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
3 Principle
Put the specimen with known area and mass into the concentrated sulfuric acid with specified concentration (applicable to organic coating) or bake at high temperature in muffle furnace (applicable to organic coating, inorganic coating and mixed coating). After the coating is completely removed, weigh the mass of the specimen and calculate the mass loss per unit area of the specimen, which is the surface density of the coating.
4 Reagents
Concentrated sulfuric acid (ρ = 1.84g/mL).
5 Apparatus
5.1 Analytical balance: with a sensitivity of 0.1 mg.
5.2 Muffle furnace, the temperature can be controlled at 550°C ± 5°C.
5.3 Oven, the temperature can be controlled at 100°C ± 1°C.
5.4 Beaker, with a capacity of 1,000 mL.
5.5 Sampler, with quantitative standard and a sample area of 0.01m2.
6 Specimens
Take a circular specimen with an area of 0.01m2 with a sampler (5.5), and the area deviation of the specimen shall not be greater than ± 0.35 cm2.
7 Concentrated sulfuric acid method
7.1 Place the specimen in an oven (5.3) at 100°C ± 1°C to dry for 5 min, then take it out with tweezers, place it in a drying dish for full cooling, and weigh the specimen mass m (accurate to 0.1 mg).
7.2 Immerse the specimen in a beaker (5.4) containing concentrated sulfuric acid (4.1) for 10 min. Rinse the specimen with tap water quickly after taking out with tweezers, and wipe the specimen surface with gauze. Place the specimen in an oven (5.3) at 100°C ± 1°C to dry for 5 min, then take it out with tweezers, place it in a drying dish for full cooling, and weigh the specimen mass (accurate to 0.1 mg).
