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This standard replaces GB/T5009.58-2003 Method for Analysis of Hygienic Standard of Polyethylene Resin for Food Packaging and GB/T 5009.59-2003 Method for Analysis of Hygienic Standard of Polystyrene Resin for Food Packaging.
The following main changes have been made with respect to GB/T5009.58-2003 and GB/T5009.59-2003 (the previous edition):
——This standard is renamed as “National Food Safety Standard - Food Contact Materials and Articles - Determination of Resin Loss on Drying”.
——The scope of the standard is modified.
National Standard for Food Safety
Food Contact Materials and Articles
Determination of Resin Loss on Drying
1 Scope
This standard specifies the determination method of loss on drying for resin in food contact materials and articles.
This standard is applicable to determination of loss on drying for polyethylene resin and polystyrene resin in food contact materials and articles.
2 Principle
The weight of polyethylene resin specimen lost when dried at 90℃~95℃ and that of polystyrene resin specimen lost when dried at 100℃ are loss on drying, which indicates existence of the volatile substance under such conditions.
3 Instruments and Apparatus
3.1 Balance: with sensitivity of 0.1mg.
3.2 Electrothermal constant-temperature dry oven.
3.3 Flat weighing bottle: with diameter of 40mm.
4 Analysis Steps
4.1 Sampling method
Operate according to GB 5009.156.
4.2 Specimen determination
4.2.1 Polyethylene resin
Weigh 5g~10g (accurate to 0.1 mg) particle specimen, put it into the flat weighing bottle with constant weight and thickness not exceeding 5mm, dry it at 90℃~95℃ for 2h and take out, then place it in the dryer for 30 min and then weigh it.
4.2.2 Polystyrene resin
Weigh 5g ~10g (accurate to 0.1 mg) particle specimen, put it into the flat weighing bottle with constant weight and thickness not exceeding 5mm, dry it at 100℃±2℃ for 3h and take out, then cool it in the dryer for 30 min and then weigh it.
Foreword i
1 Scope
2 Principle
3 Instruments and Apparatus
4 Analysis Steps
5 Expression of Analysis Results
6 Accuracy
