GB/T 23994-2009Limit of certain harmful elements of coatings for consumer products contacting with human body (English PDF)

3.1 Consumer product

Articles or parts that are used or enjoyed by consumers in or out of fixed or temporary residences, residential areas, schools, hospitals, sports fields, entertainment venues and other occasions.

3.2 Consumer product contacting with human body

6.1 Sampling

Product sampling shall be carried out in accordance with GB/T 3186.

6.2 Test method

The determination of soluble elements is carried out in accordance with the provisions of Appendix A of this Standard.

The determination of lead content is carried out in accordance with the provisions of Appendix B of this Standard.

7.2 Determination of the test result

7.2.1 The determination of the test results shall be made according to the rounding comparison method in GB/T 1250. When the test result is 0 after rounding, report the result as a valid digit.

7.2.2 When the inspection results of all items meet the requirements of this Standard, the product meets the requirements of this Standard.

A.1 Principle

Use 0.07 mol/L hydrochloric acid solution to treat the dried coating; use analytical instrument of appropriate detection-limit to quantitatively determine the content of soluble elements in the test solution.

A.2 Reagent

In the analysis test, only use reagents that are confirmed to be analytical reagents; the used water shall meet the requirements of Grade-3 water in GB/T 6682.

A.2.1 Hydrochloric acid: about 37% (mass fraction); the density is about 1.18 g/mL.

A.2.2 Hydrochloric acid solution: 0.07 mol/L.

A.2.3 Hydrochloric acid solution: about 2 mol/L

A.2.4 Nitric acid solution: 1:1 (volume ratio).

A.2.5 Antimony, arsenic, barium, cadmium, chromium, lead, mercury and selenium standard stock solutions: the concentration is 100 mg/L or 1 000 mg/L.

A.3 Instruments and apparatuses

General laboratory equipment and some of the following equipment.

A.3.1 Analytical instrument of appropriate detection-limit (see A.6): such as atomic absorption spectrometer, inductively coupled plasma atomic emission spectrometer.

A.3.2 Crushing equipment: crusher, scissors, etc.

A.3.3 Stainless steel metal sieve: pore size of 0.5 mm.

A.3.4 Balance: accuracy of 0.1 mg.

A.3.5 Heating and stirring device: the device shall be able to keep constant temperature at (37 ± 2) °C and continuously and automatically stir. The outer layer of the stirrer shall be PTFE or glass. An oscillating water bath that can keep constant temperature at (37 ± 2) °C can also be used.

A.3.6 Acidity meter: the accuracy is ±0.2 pH unit.

A.3.7 Filter membrane (applicable to aqueous solution): pore size of 0.45 µm.

A.3.8 Volumetric flask: 25 mL, 50 mL, 100 mL, etc.

A.3.9 Pipette: 1 mL, 2 mL, 5 mL, 10 mL, 25 mL, 50 mL, etc.

A.3.10 Series chemical containers: the total volume is 1.6 ~ 5.0 times the volume of the extractant of the hydrochloric acid solution (A.2.2).

A.3.11 Glass plate or polytetrafluoroethylene plate.

All glassware, sample containers, stirrers, glass plates or polytetrafluoroethylene plates must be soaked in nitric acid solution (A.2.4) for 24 hours before use, then washed with water and dried.

A.4 Test steps

A.4.1 Preparation of coating film

Stir the to-be-tested sample evenly. Prepare a mixed sample according to the specified construction ratio of the product (the thinner does not need to be added); stir evenly; then, prepare a coating film of appropriate thickness on the glass plate or polytetrafluoroethylene plate (A.3.11). Under the drying conditions that are specified in the product manual, after the coating film is completely dry (if the self-drying paint is dried, the temperature cannot exceed (60 ± 2) °C), remove the coating film; use the crushing equipment (A.3.2) to crush it at room temperature; use a stainless steel metal sieve (A.3.3) to sieve it before processing.

Note 1: For coating films that cannot be crushed (such as elastic or plastic coating films), use clean scissors (A.3.2) to cut the coating film as much as possible; directly perform sample processing without sieving.

Note 2: For powdered samples, perform sample processing directly.

A.4.2 Sample processing

Perform two parallel tests on the prepared samples.

Use a suitable chemical container (A.3.10); use a suitable pipette (A.3.9) to combine the hydrochloric acid solution (A.2.2) that is equivalent to 50 times the mass of the test sample and of a temperature of (37 ± 2) °C with the test sample.

After stirring for 1 min on the stirring device (A.3.5), use an acidity meter (A.3.6)

B.1 Principle

For the dried coating film, use a suitable method to remove all organic substances; then, use a suitable analytical instrument to determine the lead content in the test solution.

B.2 Reagent

In the analysis test, only use reagents that are confirmed to be analytical reagents; the used water shall meet the requirements of Grade-3 water in GB/T 6682.

B.2.1 Nitric acid: about 65% (mass fraction); the density is about 1.40 g/mL; nitric acid that has turned yellow shall not be used.

B.2.2 Hydrogen peroxide: about 30% (mass fraction); the density is about 1.10 g/mL.

B.2.3 Magnesium carbonate

B.2.4 Nitric acid solution: 1:1 (volume ratio). B.2.5 Nitric acid solution: 2:98 (volume ratio).

B.2.6 Lead standard stock solution: the concentration is 100 mg/L or 1 000 mg/L.

B.3 Instruments and apparatuses

General laboratory equipment and some of the following equipment.

B.3.1

Appropriate analytical instruments: such as flame atomic absorption spectrometer, inductively coupled plasma atomic emission spectrometer.

B.3.2

Crushing equipment: crusher, scissors or other suitable crushing equipment.

B.3.5

Microwave digestion system.

B.4.2.2 Wet acid digestion method

Weigh about 0.1 g ~ 0.3 g (accurate to 0.1 mg) of the crushed sample into a 50 mL beaker (B.3.8); add 7 mL of nitric acid (B.2.1); cover the mouth of the beaker with a watch glass; heat on the electric heating plate (B.3.3) to keep the solution slightly boiling for about 15 minutes; continue to heat until white smoke is produced. Remove the beaker from the electric heating plate; cool it for about 5 minutes; slowly add 1 mL ~ 2 mL of hydrogen peroxide (B.2.2) 3 times. After each addition, wait for the reaction to calm down before adding. Place the beaker on the electric heating plate again and heat until the sample is completely digested. If the sample is not fully digested, remove it and cool it slightly; then, add an appropriate amount of concentrated nitric acid (B.2.1) and hydrogen peroxide (B.2.2) one or two times; continue to heat to complete the digestion of the sample. When the remaining solution is about 1 mL, remove the beaker and cool to room temperature. Use about 10 mL of water to dilute; then, use a filter membrane (B.3.10) to filter the solution and transfer to a 50 mL volumetric flask (B.3.10). Use water to rinse the beaker and the filter membrane; collect all the obtained solutions in the same volumetric flask; then, use water to dilute to the mark. Do a reagent blank test at the same time.

B.4.2.3 Microwave digestion method

Weigh about 0.1 g ~ 0.2 g (accurate to 0.1 mg) of the crushed sample into a microwave digestion tank; respectively add 5 mL of nitric acid (B.2.1) and 2 mL of hydrogen peroxide (B.2.2); then, close the digestion tank. Perform digestion according to the following temperature program: rise to (180 ± 5) °C within about 10 min; maintain the temperature for 30 min; then, cool down. After the digestion tank is cooled to room temperature, open the digestion tank; use a filter […]