1. Appearance

    paper tube The surface area and cross-section should be smooth, clean, free of pollution and damage. The upper and lower paper tapes of Class A paper tubes should not be in the same position, and the joints should be flat with a gap of no more than 1mm

2. Classification of paper tubes

2.1A type paper tube: refers to a paper tube made through cutting, spiral tube making, rough cutting, drying, precision cutting and other processes, which can be used as a winding core tube for plastic film, paper, metal foil, film and other rolled materials.

2.2B type paper tube: refers to a paper tube made through special processing procedures such as slitting, spiral tube making, resin coating, rough cutting, drying, and precision cutting. It can be used as a winding core tube for polyester, polypropylene and other plastic films, high-end paper, metal foil and other roll shaped materials with particularly high requirements for winding flatness.

3. The inner diameter, wall thickness, length, and ultimate deviation of the paper tube should comply with the provisions in the table below

Straightness: For paper tubes with a length of less than 1000mm (including 1000mm), Class A straightness should not exceed 1mm; Class B straightness should not exceed 0.8mm; for paper tubes with a length greater than 1000mm, Class A straightness should not exceed 1.2mm; Class B straightness should not exceed 1.0mm. Moisture content: Class A should be 6.0%~12.0%; Class V samples should be subjected to temperature and humidity treatment of 6.0% to 10.0%. Before testing, the samples should be pre treated for 48 hours in an environment with a temperature of 40 ℃± 2 ℃ and a relative humidity of 20% to 35%. Then, they should be placed in a standard environment with a temperature of 23 ℃± 1 ℃ and a relative humidity of 50% ± 2% for 48 hours. Radial pressure test refers to the pressure applied vertically to the paper core shaft. The sample length is 100mm. The test pressure plate moves at a constant speed of 50-65mm/min. The value at which the force reaches its maximum for the first time or when the deformation curve stabilizes is the radial pressure value. Unit: N. The radial pressure of the paper tube should comply with the following table

The appearance of the test method is visually inspected.

The gap between the surface seams of the paper tube is measured using a steel ruler with an accuracy of 0.5mm, and the maximum value is taken from three measurements. Measure the length of the straight paper tube using a steel tape measure with an accuracy of 0.5mm at both ends, and take the average of three measurements. The internal meridian is measured using a vernier caliper with an accuracy of 0.01, and the average of three measurements is taken. The measurement of wall thickness is carried out using a vernier caliper with an accuracy of 0.01, and the average of three measurements is taken. The measurement of straightness involves placing the sample flat on a marble platform, with both eyes looking at the platform surface. The tester rotates the sample at least once to find the largest gap between the sample and the platform, and gently inserts a feeler gauge. The thickness of the gauge is the straightness. The accuracy is 0.1mm and the moisture content is tested according to the provisions of GB/T462.

4. Sampling and Judgment Principles

4.1 The appearance and dimensions adopt the sampling plan of GB/T2828.1 general inspection level I and secondary normal inspection. The qualified quality level AQL is 6.5, and the sampling is shown in the table below:

The moisture content is tested in the same batch of products according to the sampling quantity specified in the first sample of the sampling table. If it is unqualified, the batch is judged as unqualified.

Radial pressure is tested in the same batch of products according to the sampling quantity specified in the first sample in the sampling table. If one sample is unqualified, the batch is judged as unqualified.

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