1 Scope
This document specifies the classification and grading, requirements, test methods, inspection rules and marking, packaging, transport and storage of composite plastic lidding films for food packaging.
This document applies to composite films for sealing food containers with plastic as the heat-laminated layer.
2 Normative references
The contents of the following documents constitute essential provisions of this document through the normative references in the text. Among them, note the date of the reference document, only the date of the corresponding version applies to this document; do not note the date of the reference document, its latest version (including all the revision of the list) applies to this document.
GB/T 191 Pictorial marking of packaging, storage and transport
GB/T 1037 Test method for water vapour permeability of plastic films and sheets, cup method
GB/T 1038 Test method for gas permeability of plastic films and sheets Differential pressure method
GB/T1040.3-2006 Determination of the tensile properties of plastics Part 3: Test conditions for films and sheets
GB/T 2410 Transparency Determination of light transmittance and haze of plastics
3 Terminology and definitions
There are no terms and definitions that need to be defined in this document.
4 Classification and grading
4.1 According to the conditions of use
Products according to the conditions of use, divided into ordinary grade, boiling grade, semi-high temperature swallow cooking grade and high temperature cooking grade.
The use temperature of each level should be in accordance with the provisions of Table 1.
4.2 According to the strength of the thermal bonding with the container
Products are divided into two categories according to their thermal strength with the container: can be uncovered from the class and can not be uncovered from the class.
The classification should be in accordance with the provisions of Table 2.
4.3 Water vapour transmission
The products are classified according to the size of the water vapour transmission into class 1, class 2, class 3 and class 4.
4.4 Oxygen transmission capacity
The products are classified as Class 1, Class 2, Class 3 and Class 4 according to the size of oxygen transmission.
5 Requirements
5.1
Appearance quality
The appearance quality should be in accordance with the provisions of Table 3.
5.2 Printing quality
5.2.1 Gravure printing
The quality of gravure printing shall conform to the provisions of GB/T 7707.
5.2.2 Flexographic printing
Flexographic printing quality should comply with the provisions of GB/T 17497.1 or GB/T 17497.2.
5.2.3 Bar code printing
The quality of barcode printing should comply with the provisions of GB 12904 and GB/T 14257.
5.2.4 Chinese letter code printing
The printing quality of the Hanshin code should comply with the provisions of GB/T 21049.
5.3 Dimensional deviation
5.3.1 Roll film size deviation
The dimensional deviation shall conform to the provisions of Table 4.
5.3.2 Size and deviation of the core of the film
The inner diameter is φ76 +8mm or φ152 +daymm, special requirements shall be negotiated between the supply and demand sides.
5.4 Joints
Joints shall conform to the provisions of Table 5.
5.5
Physical and mechanical properties
5.5.1 Inner layer peeling force
The inner peel force shall conform to the provisions of Table 6
6 Test methods
6.1 Standard environment for specimen condition adjustment and test
The temperature shall be 23C±2C, relative humidity 50%±10%, state conditioning time not less than 4h, and test under these conditions as specified in GB/T2918--2018.
6.2 Sampling
The sample shall be intact and the number of samples taken shall be sufficient to complete the test. Samples shall be taken by removing the three layers from the surface of the membrane roll and then cutting the sample along the width of the membrane roll.
6.3 Quality of appearance
Visual inspection in natural light and measurement with a gauge of not less than 0.5mm accuracy.
6.4 Printing quality
6.4.1 Gravure printing quality
According to the provisions of GB/T 7707.
6.4.2 Flexographic printing quality
According to the provisions of GB/T 17497.1 or GB/T 17497.2.
6.4.3 Barcode printing quality
According to the provisions of GB/T 14258 .GB/T 18348
6.4.4 Hanxin code printing quality
According to the provisions of GB/T 21049.
6.5 Dimensional deviation
6.5.1 Length and width deviation
Carried out according to the provisions of GB/T 6673.
6.5.2 Thickness deviation
According to the provisions of GB/T 6672
6.5.3 Repeat length deviation
Measured with a gauge with an accuracy of not less than 0.5 mm. For repeat length less than 80 mm to take 10 consecutive repeat length measurement, and then take the arithmetic mean calculation; for repeat length greater than or equal to 80 mm to take 5 consecutive repeat length measurement, and then take the arithmetic mean calculation.
6.6 Physical and mechanical properties
6.6.1 Inner layer peeling force
According to the provisions of GB/T 8808.
6.6.2 Thermal bonding strength
6.6.2.1 The method and conditions of heat lamination of the film and the sheet of simulated food containers are agreed between the supply and demand sides.
6.6.2.2 After the lid film and the sheet have been sealed by the heat sealing tester, the film is opened at 180° with the heat sealing part as the centre. The cover film is clamped in the upper jig of the tester and the sheet is clamped in the lower jig, with the specimen axis coinciding with the centre line of the upper and lower jigs. The distance between the clamps is 50 mm, the test speed is 300 mm/min ± 20 mm/min, and the maximum load is read when the specimen and the sheet are delaminated or the specimen is broken.
6.6.2.3 Other conditions refer to the provisions of QB/T 2358.
6.6.3 Water vapour transmission capacity
According to the provisions of GB/T1037 or GB/T26253. Test the contents of the contact surface towards the low pressure side of water vapour or the low concentration side of water vapour, test temperature 38 C ± 0.6 C, relative humidity 90% ± 2%.
GB/T 1037 is the arbitration method.
6.6.4 Oxygen transmission capacity
GB/T1038 or GB/T19789 according to the provisions. Test the contents of the contact surface towards the low pressure side of oxygen or oxygen low concentration side.
GB/T 1038 for arbitration methods.
6.6.5 Tensile force and fracture nominal strain
According to the provisions of GB/T 1040.3- 2006.
Specimen using type 2 long strip, length greater than or equal to 150 mm, width of 15 mm ± 1 mm, specimen fixture spacing of 100 mm ± 1 mm, specimen stretching speed of 200 mm/ min ± 20 mm/ min.
6.6.6 Right-angle tearing force
According to QB/T 1130.
6.6.7 Friction coefficient
As specified in GB/T 10006.
6.6.8 Resistance to pendulum impact
As specified in GB/T 8809.
6.6.9 Heat resistance
Seal the container with the cover film heat sealing 1/2 to 2/3 of the water after filling. Put in the heating container for heating (if the use temperature exceeds 100 C, the heating container should be equipped with a counter-pressure device). The boiling or steaming temperature is the maximum temperature for the type of sample used or the temperature agreed between the supplier and the customer, and the holding time is 30 min or the time agreed between the supplier and the customer. After heating, allow to cool naturally to room temperature and check that the cover film is not significantly deformed, peeling between layers, peeling in the heat-laminated area, etc.
6.6.10 Cold resistance
Seal the container with 1/2~2/3 of water in the heat seal of the cover film, keep it at 18 C for 12 h, then thaw it naturally at room temperature or warm it up to 10 C~20 C with warm water of about 20 C. Check whether there is any obvious deformation of the cover film, peeling between layers, peeling of the heat seal part, etc.
6.6.11 Puncture strength
According to the provisions of GB/T 21302.
6.6.12 Light transmittance and haze
According to the provisions of GB/T 2410.
6.7 Joints
Visually inspected in natural light.
7 Inspection rules
7.1 Inspection classification
Product inspection is divided into factory inspection and type inspection.
7.2 Factory inspection
7.2.1 Group batch
With the same raw materials, the same process of continuous production of the same category, the same material structure, the same specification of the product as a batch. The maximum group batch does not exceed 500000m2.
7.2.2 Inspection items
The inspection items are appearance quality (5.1), printing quality (5.2). Dimensional deviation (5.3) . Joints (5.4), inner layer peeling force (5.5.1) and thermal bonding strength (5.5.2).
7.3 Type test
7.3.1 Test items
The test items are all those specified in Chapter 5.
7.3.2 Inspection frequency
One of the following cases, should be type test:
a) new product prototype identification;
7.4 Sampling programme and determination rules
7.4.1 Appearance quality, printing quality, joints and dimensional deviations
According to GB/T 2828.1-2012, a normal inspection secondary sampling scheme shall be adopted, with the acceptance quality limit (AQL) = 6.5. The decision shall be made according to Table 10.
The unit for rolls of film is the roll and the unit for sheets of film is the sheet. If the batch size is less than the required sample size, the entire batch size shall be sampled.
7.4.2 Inner layer peel strength and heat seal strength
Random sampling within a batch is used for testing. If the number of rolls is less than or equal to 3, the number of samples shall be 1; if the number of rolls is greater than 3, the number of samples shall be 3, with 1 m of each roll being taken.
7.4.3 Other physical and mechanical properties
A random sample of a batch shall be used for testing. If the number of rolls of film in a batch is less than or equal to 3, the sampling quantity shall be 1 roll; if the number of rolls of film in a batch is greater than 3, the sampling quantity shall be 3 rolls. A sample of 2 m shall be taken from each roll.
7.5 Conformity determination
7.5.1 Judgement of conformity
7.5.1.1 Appearance quality
If the provisions of 5.1 are met, the appearance quality is judged to be satisfactory.
7.5.1.2 Printing quality
If the provisions of 5.2 are met, the printing quality is judged to be satisfactory.
8 Marking, packaging, transport and storage
8.1 Marking
Each package of the product shall be accompanied by a product certificate of conformity and marked with the product name. Specification, quantity, quality, batch number, production date, inspector code, producer's name, producer's address and this document number.
8.2 Packaging:
Plastic film or paper that meets the requirements of food packaging shall be used as the inner packaging.
8.3 Transport
When transporting, prevent collision or contact with sharp objects, load and unload lightly, avoid sun and rain, and ensure that the packaging is intact and the product is not contaminated. The marking method should be carried out in accordance with the provisions of GB/T 191.
8.4 Storage
The product should be stored in a clean, dry and ventilated warehouse, away from sunlight. Not less than 1m away from heat sources.
Bibliography
1 Scope
2 Normative references
3 Terminology and definitions
4 Classification and grading
5 Requirements
6 Test methods
7 Inspection rules
8 Marking, packaging, transport and storage
Bibliography
