GB/T 22638.4-2016Test methods for aluminium and aluminium alloy foils—Part 4: Determination of surface wetting tension (English PDF)

Foreword

GB/T 22638, Test methods for aluminium and aluminium alloy foils, consists of 10 parts.

-- 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 by brushing;

-- Part 6: Determination of DC;

-- 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 Part is Part 4 of GB/T 22638.

This Part is drafted in accordance with the rules given in GB/T 1.1-2009.

This part replaces GB/T 22638.4-2008 Test methods for aluminium and aluminium alloy foils - Part 4: Determination of surface wetting tension. As compared with GB/T 22638.4-2008, the main technical changes are as follows.

-- Modify the solution ratios in Table 1;

-- Modify the surface wetting tension value corresponding to test solution of serial number 30 in Table 2 from 66 to 65;

-- Change the thickness of the outer layer of the aluminum foil roll to be removed before testing to 3 mm;

-- Add the "dyne pen method" for measuring surface wetting tension;

-- Add the requirement that "if the surface wetting tension is measured directly on the aluminum foil roll, the test solution shall be prevented from contaminating the end face of the aluminum foil roll";

-- Add the requirement that "repeated testing shall not be performed on the same area of the aluminum foil surface".

1 Scope

This Part of GB/T 22638 specifies the method principle, reagents and materials, test conditions, sampling, swab method, dyne pen method and test report for the determination of surface wetting tension of aluminium and aluminium alloy foils.

This Part applies to the determination of surface wetting tension of aluminium and aluminium alloy foils.

The swab method specified in this Part is the arbitration method for the determination of surface wetting tension of aluminium and aluminium alloy foils.

2 Method principle

This method utilizes the principle that different liquids have different surface wettability on the same material, uses test solutions of different ratios to test the surface of aluminium and aluminium alloy foils, to determine the surface wetting tension of aluminium and aluminium alloy foils.

3 Reagents and materials

3.1 Formamide, analytical reagent.

3.2 Ethylene glycol ethyl ether, analytical reagent.

3.3 Distilled water.

3.4 Tweezers.

3.5 Absorbent cotton.

3.6 Test solutions. Take formamide (3.1), ethylene glycol ethyl ether (3.2) and distilled water (3.3) and prepare the corresponding test solutions according to Table 1.

4 Test conditions

4.1 Room temperature. 23 °C ± 2 °C

5 Sampling

Remove at least 3 mm of the outer layer of the aluminium and aluminium alloy foil roll before testing.

6 Swab method

6.1 Use tweezers to pick up an absorbent cotton ball; dip it in the prepared test solution (3.6); wipe the aluminum foil surface along the width direction, as shown in Figure 1.

Wipe the sample surface by the absorbent cotton for an area not less than 600 mm², and observe the cracking of the test solution on the aluminum foil surface.

6.2 If the surface wetting tension is measured directly on the aluminum foil roll, the test solution shall be prevented from contaminating the end face of the aluminum foil roll.

6.3 Repeated testing shall not be performed on the same area of the aluminum foil surface.

6.4 If the test solution does not break into small droplets within 2 seconds, the test solution of the next serial number shall be selected for retesting until the test solution breaks into small droplets within 2 seconds. The surface wetting tension corresponding to the test solution of the previous serial number is then determined as the surface wetting tension value of the aluminum foil being tested (see Table 2). If the initially selected test solution breaks within 2 seconds, the test solution of the previous serial number shall be selected for retesting until the test solution does not break within 2 seconds. The surface wetting tension corresponding to this test solution is then determined as the surface wetting tension value of the aluminum foil being tested (see Table 2). […]