Some standard content:
GB/T16958--1997
There are no national and industry standards for biaxially oriented polyester films for packaging at home and abroad. Only some enterprises have enterprise standards or product export technical conditions. In the process of formulating this standard, some enterprise standards of the country were mainly referred to. In the process of formulating this standard, similar products at home and abroad were collected, and their various performances were tested and compared. The technical requirements specified in this standard are limited to products for packaging. This standard was proposed by China National Packaging Corporation. This standard is under the jurisdiction of the National Packaging Standardization Technical Committee. The main drafting units of this standard are: National Packaging Product Quality Supervision and Inspection Center (Tianjin), Foshan DuPont Hongji Film Co., Ltd., Ningbo Wuzhou Co., Ltd.
The main drafters of this standard are: Zhao Shichao, Li Yizhuang, Hua Keqin, Zhang Guiyun, Feng Yong, Hu Jiaoming. 167
1 Scope
National Standard of the People's Republic of China
Biaxially oriented polyester film for package
Biaxially oriented polyester film for packageGB/T16958—1997
This standard specifies the product specifications, requirements, test methods, inspection rules, marking, packaging, transportation and storage of biaxially oriented polyester film for package (hereinafter referred to as polyester film).
This standard applies to the production, use, circulation and supervision inspection of biaxially oriented films made of polyethylene terephthalate resin as raw material.
2 Cited Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB1037—88Test method for water vapor permeability of plastic film and sheet Cup method GB 1038---70
GB 2410--80
GB 282887
GB 2918—82
GB 6672--86
GB 6673-—86
Test method for air permeability of plastic film
Test method for light transmittance and haze of transparent plastics Batch inspection counting sampling procedure and sampling table (applicable to inspection of continuous batches) Standard environment for conditioning and testing of plastic specimens Determination of thickness of plastic film and sheet Mechanical determination method Determination of length and width of plastic film and sheet GB 10006--88
GB 13022—91
GB 13113---91
Determination method of friction coefficient of plastic film and sheetTest method for tensile properties of plastic film
Sanitary standard for polyethylene terephthalate molded products for food containers and packaging materialsGB/T14216--93Test method for wetting tension of plastic film and sheet3 Definitions
This standard adopts the following definitions.
Polyester film Biaxially oriented polyester film (BOPET) is a film made by stretching, orienting, shaping, cooling and other treatments of polyester resin cast sheets in the longitudinal and transverse directions under certain temperature and stretching ratio conditions.
4 Specifications (see Table 1)
Table 1 Specifications of polyester film
Thickness, μum
Width, mm
Approved by the State Administration of Technical Supervision on August 26, 1997 168
320~2000
Implementation on February 1, 1998
5 Requirements
5.1 Dimensional deviation
GB/T 16958—1997
5.1.1 The thickness deviation of polyester film shall comply with the requirements of Table 2. Table 2
Nominal thickness
Average thickness deviation,
Superior product
Width deviation±2mm
First-class product
Thickness deviation of polyester film
Qualified product
Superior product
Thickness deviation,
First-class product
The number of joints and the length of each section shall comply with the provisions of Table 3. The joints shall be flatly affixed with double-sided tape across the entire width and have obvious markings. Number of joints and the shortest length of finished membrane
Nominal thickness
Length of each roll, m
Appearance (see Table 4)
Appearance of curling
Scars and wrinkles
Uneven end faces
Bubbles, pinholes, oil stains
End of paper core
Number of joints, pieces
Superior products
Superior products
≤5 pieces/m2
Qualified products
Appearance quality of finished membrane
≤1u piece/m 2
Surface smooth
Not allowed
≤2mm
Not allowed
Length of each section, m
Superior product
Qualified product
Qualified product
Qualified product
No impact on use
Petals are allowed
No impact on use
Polyester film with a thickness of less than 30μum is allowed to have slight longitudinal stripes without radial depressions or collapses
5.3 The physical and mechanical properties shall comply with the requirements of Table 5. Table 5 Physical and mechanical properties of polyester film
Tensile strength, MPa
Longitudinal》
Superior products
First-class products
Qualified products
Elongation at break, %
Heat shrinkage, %
(150°C, 30 min)
Haze,
Gloss,
((static/dynamic)
Friction coefficient
Wetting tension, mN/m
GB/T 16958--1997
Table 5 (end)
Superior products
Vertical》
Horizontal》
First-class products
0.55/0.65
No treatment 40
Corona treatment 50
Qualified products
5.4 When oxygen permeability, moisture permeability and light transmittance tests are carried out according to the needs of users, the performance requirements and test methods are shown in Appendix A. 5.5 The hygienic indicators of polyester films used for food packaging shall comply with the provisions of GB13113. 6 Test Test method
6.1 Sample preparation
6.1.1 Sampling method
First remove 3 to 5 layers of the outer film of the roll to be tested, then take samples according to the specified number and keep records. Cut about 7 layers along the transverse direction of the film roll for appearance, specification size and physical performance testing. Roll it with a paper core to prevent the sample from being contaminated. 6.1.2 Pretreatment
The sample state adjustment should be carried out in a standard environment of (23 ± 1) ℃ and relative humidity of (50 ± 5)% for a time of not less than 4 hours, and the test should be carried out under this condition.
6.2 Thickness The measurement
shall be carried out in accordance with GB6672. The measuring instrument accuracy is higher than 0.2HM, and the thickness deviation is calculated according to the maximum deviation value. The average thickness deviation is the percentage of the difference between the average thickness and the nominal thickness to the nominal thickness. 6.3 The width shall be measured
in accordance with GB6673.
6.4 Appearance
visual inspection under natural light or lighting.
6.5 The tensile strength and elongation at break shall be measured in accordance with GB13022. The specimen shall be 150mm long and (15±0.1)m wide. m strip, the distance between the clamps is 100mm, the tensile speed is (100±10)mm/min, and 5 longitudinal and transverse specimens are tested respectively. 6.6 Haze
Perform according to GB2410.
6.7 Friction coefficient
Perform according to GB10006.
6.8 Heat shrinkage
6.8.1 Test apparatus
a) Oven (temperature accuracy ±1℃);
b) Measuring tool with an accuracy of 0.1mm;
c) Stopwatch.
6.8.2 Test specimen
GB/T 16958—1997
The test specimen is 5 square specimens of 120mm×120mm, and there are 100mm×100mm marking lines perpendicular to each other in the middle of the longitudinal and transverse directions of the specimen.
6.8.3 Test steps
Adjust the oven temperature to (150±1)℃, quickly put in the sample, start timing, lay the sample flat, keep it for 30 minutes, then take it out. After cooling to the test environment temperature, measure the length of the vertical and horizontal markings respectively, calculate the thermal shrinkage of the sample, and take the arithmetic mean as the measurement result, accurate to one decimal place.
6.8.4 Calculation formula
T = (L - L)/L× 100
Where: T heat shrinkage, %;
L. — Length before heating, mm;
L, length after heating, mm. bzxz.net
6.9 Determination of wetting tension
Perform according to GB/T14216.
6.10 Glossiness
6.10.1 Test instrument
Gloss meter (45° refraction) with an accuracy of 0.1. 6.10.2 Sample
Length 100mm, width 100mm, quantity 5 pieces.
The edges and surfaces of the sample shall not have cracks or damage. 6.10.3 Test steps
a) Turn on the power of the gloss meter, place two standard calibration samples on the light transmission hole one after another, and adjust the corresponding standard values; (1)
b) Take out the calibration sample, place the sample film on the light transmission hole, read the gloss value, take the arithmetic mean of the measured values of 5 samples as the test result, and take the integer.
6.11 Determination of hygiene indicators
Carry out in accordance with Chapter 5 of GB13113.
7 Inspection rules
7.1 Factory inspection
7.1.1 Composition of inspection batch
Polyester films of the same specifications produced with the same raw materials and the same process conditions are one inspection batch, and each batch shall not exceed 30 tons. 7.1.2 Inspection items include size, appearance and physical and mechanical properties. 7.1.3 The dimensional deviation, joints and appearance of polyester film shall be sampled according to the requirements of Table 6, and tested according to 6.1~6.4 and meet the requirements of 5.1 and 5.2.
7.1.4 The physical and mechanical properties of polyester film shall be sampled from at least one roll in each batch, and tested according to 6.5 and 6.8 and meet the requirements of Table 5. 7.2 Type test
7.2.1 The composition of the test batch shall be carried out according to 7.1.1. 7.2.2 Type inspection shall be conducted in any of the following cases: a) new products or old products are tested for trial production; b) after formal production, the process has changed significantly, which may affect product performance; c) during normal production, the inspection shall be conducted every six months; d) after a long period of suspension, the production of the product is resumed; e) when the results of the product inspection are significantly different from those of the last type inspection; f) when the national quality supervision and inspection agency proposes to conduct type inspection. 7.2.3 Type inspection items shall be conducted in accordance with Chapter 5 of this standard. Table 6 Sampling and judgment of dimensional deviation, joints and appearance of polyester film Batch
26~50
91~150
151~230
231~500
501~1200
1201~~3200
3 201~10 000
Above 10 000
7.3 Judgment of inspection results
First
Sample size
Cumulative sample size
Qualified judgment number Ac
Unqualified judgment number R.
7.3.1 If any two of the dimensional deviation, joints, and appearance of polyester film are unqualified, the roll is unqualified, and the qualified batch is determined according to Table 6. 7.3.2 If any one of the physical and mechanical properties of polyester film is unqualified, the unqualified item should be double sampled and retested in the original batch. If the retest result is still unqualified, the entire batch is unqualified. 8 Marking, packaging, transportation, storage
8.1 Marking
The film roll should have a certificate of conformity, and the packaging box should have the manufacturer's name, address, this standard number, trademark, product name, specification, length, batch number, production date, grade, and "moisture-averse, heat-averse, and impact-resistant" marks. 8.2 Packaging
Each roll of polyester film should be protected by pads at both ends, wrapped with film, and tied tightly. Special packaging shall be agreed upon by the supply and demand parties. 8.3 Transportation
It should be handled with care during transportation to prevent mechanical collision and sun and rain. 8.4 Storage
Polyester film should be stored in a clean, dry and ventilated warehouse, away from direct sunlight, and the shelf life should not exceed one year from the date of production. 172
A1 Oxygen permeability
GB/T16958-1997
Appendix A
(Suggestive Appendix)
Requirements and test methods for oxygen permeability, moisture permeability and light transmittance The oxygen permeability requirement is 2.25×10-15cm2·cm/(cm2·S·Pa). A2 Moisture permeability
A2.1 The moisture permeability requirement is 55g/(m2·24h) (thickness is 0.012μm). A2.2 The moisture permeability test is carried out in accordance with GB1037, with a temperature of (23±1)℃ and a relative humidity of (90±2)%. A3 Light transmittance
A3.1 The light transmittance requirement is 85%.
A3.2 Determination of light transmittance
A3.2.1 Sample size: 50mm×50mm, the sample should be uniform, without bubbles, and the two measuring surfaces should be flat, smooth, without scratches, foreign matter and oil stains. Each group of samples should be no less than 3. A3.2.2 The test method shall be carried out in accordance with the provisions of GB2410. Note: For special requirements, please refer to this appendix. 1733 Transportation
Handle with care during transportation to prevent mechanical collision and exposure to sunlight and rain. 8.4 Storage
Polyester film should be stored in a clean, dry and ventilated warehouse, away from direct sunlight, and the shelf life should not exceed one year from the date of production. 172
A1 Oxygen permeability coefficient
GB/T16958-1997
Appendix A
(Suggestive Appendix)
Requirements and test methods for oxygen permeability coefficient, moisture permeability and light transmittance The oxygen permeability requirement is 2.25×10-15cm2·cm/(cm2·S·Pa). A2 Moisture permeability
A2.1 The moisture permeability requirement is 55g/(m2·24h) (thickness is 0.012μm). A2.2 The moisture permeability test shall be carried out in accordance with the provisions of GB1037, with a temperature of (23 ± 1) °C and a relative humidity of (90 ± 2)%. A3 Light transmittance
A3.1 The light transmittance requirement is 85%.
A3.2 Determination of light transmittance
A3.2.1 Sample size: 50mm×50mm, the sample shall be uniform, without bubbles, and the two measuring surfaces shall be flat, smooth, without scratches, foreign matter and oil stains. Each group of samples shall not be less than 3. A3.2.2 The test method shall be carried out in accordance with the provisions of GB2410. Note: For special requirements, please refer to this appendix. 1733 Transportation
Handle with care during transportation to prevent mechanical collision and exposure to sunlight and rain. 8.4 Storage
Polyester film should be stored in a clean, dry and ventilated warehouse, away from direct sunlight, and the shelf life should not exceed one year from the date of production. 172
A1 Oxygen permeability coefficient
GB/T16958-1997
Appendix A
(Suggestive Appendix)
Requirements and test methods for oxygen permeability coefficient, moisture permeability and light transmittance The oxygen permeability requirement is 2.25×10-15cm2·cm/(cm2·S·Pa). A2 Moisture permeability
A2.1 The moisture permeability requirement is 55g/(m2·24h) (thickness is 0.012μm). A2.2 The moisture permeability test shall be carried out in accordance with the provisions of GB1037, with a temperature of (23 ± 1) °C and a relative humidity of (90 ± 2)%. A3 Light transmittance
A3.1 The light transmittance requirement is 85%.
A3.2 Determination of light transmittance
A3.2.1 Sample size: 50mm×50mm, the sample shall be uniform, without bubbles, and the two measuring surfaces shall be flat, smooth, without scratches, foreign matter and oil stains. Each group of samples shall not be less than 3. A3.2.2 The test method shall be carried out in accordance with the provisions of GB2410. Note: For special requirements, please refer to this appendix. 173
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