Paper lunch box inspection

Paper lunch boxes are an environmentally friendly food packaging container, usually made of food-grade paper, kraft paper or coated paper. It can be used once or recycled using biodegradable materials as needed. Paper lunch boxes are widely used in takeout, fast food, bento and various food packaging, and are the preferred alternative to plastic lunch boxes. So, how do third-party inspection companies inspect paper lunch boxes? What are the requirements and methods for inspecting paper lunch boxes?

Appearance requirements for paper lunch box inspection

Observe the appearance of the entire paper lunch box under natural light or fluorescent light. Visually inspect 10 paper lunch boxes for each sample of printing and inner wall coating.

Paper lunch boxes should not be dented or wrinkled; the coating layer should be uniform. The printed pattern on the paper lunch box should have clear outlines, uniform color, and no obvious color spots. The paper lunch box should be clean and free of foreign matter, and should not have any odor.

If two or more (including two) paper lunch boxes do not meet the requirements, the item will be deemed unqualified.

Paper lunch box inspection and performance requirements

The performance of paper lunch boxes should comply with the requirements of Table 1 or the contract.

Indicator name		unit	Regulation
Cover fold test		—	There should be no cracks
Dimensional deviation	Bottom long side	mm	±2
	Bottom short side		±2
	slant height		±3
Temperature resistance test (oil and water at 95℃±5℃, 30 min)			No deformation, peeling, wrinkling, seepage or leakage
Load-bearing performance		%	≤5.0

Paper lunch box inspection cover body connection folding performance requirements

For the paper box with lid sample, fold the lid in half 15 times and observe whether there are cracks at the connection between the lid and the box body. 10 paper lunch boxes are tested for each sample. If more than 2 (including 2) paper lunch boxes do not meet the requirements, the item is judged as unqualified.

Method for measuring dimensional deviation of paper lunch box inspection

Use a vernier caliper with an accuracy of 0.02 mm to measure the long side of the bottom, the short side of the bottom and the oblique height. Measure 5 specimens for each sample. The results are expressed as the difference between the maximum and minimum values ​​and the average value.

Paper lunch box inspection and heat resistance test method

Place the paper lunch box on a dry glass plate, and inject 95℃±5℃ edible oil and water to 6 mm from the opening of the paper lunch box. Cover the box and let it stand for 30 minutes, then observe whether the sample is deformed or cracked, whether the surface is peeling or wrinkled, and whether there is oil or water seepage or leakage from the bottom and sides of the sample.

Test method for load-bearing performance of paper lunch box inspection

Test equipment

220mm×150mm×3mm flat glass, 3kg weight, metal ruler with accuracy to 1mm.

Test steps

Open the lid of the paper lunch box and turn it upside down on a smooth tabletop, then place a flat glass on the bottom of the box. Use a metal ruler to measure the height from the lower surface of the flat glass to the horizontal tabletop. Then place a 3 kg weight in the center of the flat glass, and immediately measure the height after loading for 1 minute. Measure 2 paper lunch boxes separately and calculate the load-bearing performance of each sample using the formula. Take the arithmetic mean of the measured values ​​of the 2 paper lunch boxes as the load-bearing performance of the paper lunch box.

Paper lunch box inspection mark and packaging requirements

The marking and packaging of paper lunch boxes should be carried out in accordance with GB/T10342 or the provisions of the contract.

All packaging materials of paper lunch boxes should have sufficient sealing and firmness to ensure that the paper lunch boxes are not contaminated under normal transportation and storage conditions. Paper lunch box packaging should be dustproof, moisture-proof or mildew-proof, and packaging materials that directly contact the product should be non-toxic, harmless and clean.