Some standard content:
National Standard of the People's Republic of China
Polyethylene self-adhesive cling film
Cling wrap polyethylene film for keeping fresh of food
Theme content and scope of application
GB 10457--89| |tt||This standard specifies the technical requirements, test methods, inspection rules, etc. for polyethylene self-adhesive cling film (hereinafter referred to as cling film). This standard applies to cling film made of polyethylene resin as the main raw material, used for food packaging, and has fresh-keeping, cleaning and self-adhesive properties. Reference standards
2
GB1037
GB1038
GB1040
GB2410
GBn 84
GB 6388||tt| |GB6543
GB 6672
Test methods for water vapor permeability of plastic films and sheets Test methods for air permeability of plastic films
Tensile test methods for plastics
Transparent plastics Test methods for light transmittance and haze Hygiene standards for polyethylene molded products
Transport packaging receipt and delivery marks
Corrugated boxes
Determination of thickness of plastic films and sheets Mechanical measurement method HG 2 - —167
3 terms
Plastic tear strength test method
Self-adhesiveness: the adhesiveness of the plastic wrap itself. Unwindability: The ease with which the plastic wrap can be pulled out of the film roll during use. Anti-fog: The plastic wrap has the property of preventing water droplets or mist from forming on its surface. 4Technical Requirements
4.1
Specifications, dimensions and deviations shall comply with the requirements of Table 1. Size and deviation
item
width
original degree
length
m
nominal ruler
300||tt ||0.0060.010
0.011 ~ 0,020
20, 30, 50, 100
Table 1
Note: It can be made into different thicknesses according to user needs. width and length. China Packaging Corporation 1989-03-03 approved 58
other products
± 2
+0.002
0
±0.002
Bias
Difference
No negative deviation allowed
Qualified product
± 4
+0.002
0.001
±0.003
mm
Implemented on 1989-10-01
4.2
The appearance should meet the requirements of Table 2
Product
Indicator name|| tt||Bubbles, perforations and ruptures
Impurities, pieces/㎡2
>0.6mm
0.3~0.6mmbZxz.net
Grade
Dispersion, Pieces/10cm×J0cm
“Fisheye” and “Yan block”, pieces/m2
2mm
0.2~ 2 mm
Dispersion, pieces/10cm× 10cm
State full degree
4.3
GB 10457--89
Table 2
Other products
Not allowed||tt ||Not allowed
No more than 5
No more than 2
Not allowed
No more than 10
No more than 3||tt ||With quality products
Not allowed
Not allowed
No more than 8
No more than 5
Not allowed
No More than 20
Not more than 5
The surface of the cling film is basically flat, and slight wrinkles are allowed. There is a small amount of film edge beyond the paper core, but there are no loose pleats, and the end face of the film roll is smooth
The physical and mechanical properties should meet the requirements of Table 3. Item name
Tensile strength, MPa
Elongation at break, %
Right angle tear strength, N/cm
Gas transmission rate
cm*/(m2-24h.atm)
Light transmittance, %
Haze, %
Water vapor transmission, 8/(m2.24h)||tt| |Self-adhesiveness (shear peel strength),
N/cm
Longitudinal
Transverse
Longitudinal
Transverse
Longitudinal|| tt||Transverse direction
Oxygen
Carbon dioxide
Uncoilability: The sample should be completely peeled off within 5s. 4.4
Table 3
must affect the film roll being pulled out of the carton
Indicator requirements
not less than 10
not less than 120|| tt||not less than 400
7 000~ 20 000
not less than 50000
not less than 90
not more than 3
50 ~400
not less than 0.5
59
GB 10457 -- 8#
4.5 Anti-fog: Under test conditions, there should be no water beads on the surface of the plastic wrap Attached, only small water droplets are attached locally. There should be no water droplets attached to the surface of the plastic wrap over a large area.
4.6 Hygienic indicators: The hygienic indicators of plastic wrap should comply with the regulations of GBn84. 5 Test method
5.1 Sampling method
After removing at least 2m from the outer end of the roll film, cut out a sample of 5m and 2m respectively. The 5m sample is used for physical and mechanical properties, health indicators, etc. Use, 2m sample for appearance inspection. 5.2 Test environment and sample pretreatment
Ambient temperature: 23±2℃
Relative humidity: 50%±5%
Pretreatment time: not less than 4h||tt ||5.3 Determination of thickness
According to the provisions of GB 6672.
5.4 Determination of width and length
Unroll the plastic wrap on a flat, clean table and measure directly with a steel tape measure, leather tape measure or steel ruler. The width is measured 10 times at equal intervals, and the maximum and minimum values ??are taken, accurate to 1mm. The length is measured 3 times at equal intervals, and the minimum value is taken, accurate to 1cm5.5 Appearance Inspection
5.5.1 Bubbles for Appearance Indicators , perforation cracks and flatness are visually inspected under natural light. 5.5.2 The size of impurities, "fish eyes" and "stiff lumps" are inspected with a 10x magnifying glass, calculated based on the maximum length, and the degree of dispersion is inspected with a 10cm × 10cm frame plate.
5.6 Determination of physical and mechanical properties
5.6.1·The determination of tensile strength and elongation at break shall be carried out in accordance with the provisions of the film item in GB1040. The tensile speed is 250±50mn/min. 5.6.2 Determination of right-angle tear strength
According to the provisions of HG2-167, the strapping test group is used for testing. 5.6.3 The measurement of gas transmittance
shall be carried out in accordance with the provisions of GB1038.
5.6.4 Determination of water vapor transmission amount
According to the provisions of GB1037.
5.6.5 Measurement of light transmittance and haze
According to the provisions of GB2410.
5.6.6 Determination of self-adhesiveness (shear peel strength) 5.6.6.1 Preparation of specimens
Cut a sample + piece of 50mm long and 25mm wide, and use two pieces as a group to make the test The adhesive surfaces of the sample are opposite in the length direction, and overlapped from end to end. The length of the overlapped part is 15mm and the width is 25mm. Place the sample on a smooth surface and roll it with a rubber (blood 40mm, L=100mm, W=300g) Roll the overlapping part of the sample back and forth three times to ensure that no air remains between the two layers of plastic wrap at the overlapping part. Place the prepared sample under the test environmental conditions for 20 minutes, and then conduct the test. 5.6.6.2 Test method
Stretch each group of specimens on a tensile machine, measure the force required to separate the two specimens, and take the arithmetic mean of the five groups of specimens. The testing equipment should comply with the regulations of GB1040. The tensile speed is 250±50mm/min. Calculation formula:
60
GB 10457-89
Shear peel strength
formula Middle: P force required for specimen separation, N, b overlap width, cm
overlap length, cm.
5.7 Determination of unwindability
5.7.1 Preparation of sample
P
axb
(N/cm2)
Cut six pieces of the sample 50mm wide and 150mm long, and use two pieces as one Set, the adhesive surfaces are relatively fit, and the fit length is 100mm. The processing and treatment methods are the same as 5.6.6.1 of this standard. 5.7.2 Test method
As shown in the figure below, fix one end of the sample, and the other end is fixed by the self-adhesiveness of the plastic wrap or tape 4 If you have multiple heavy objects, put them down slowly and let them peel off naturally. All three groups of specimens shall comply with the requirements of 4.4 of this standard. 4 guest
5.8 Determination of anti-fog property
Add 200mL of water at 23±2℃ into each of three 1000mL beakers, use three pieces of plastic wrap with the same area, with the adhesive side facing down. Separately cover the cup mouth tightly and make the membrane surface flat, and place it in a low temperature box at about 3°C ??to maintain a constant temperature. After 10 minutes, observe the adhesion state of water droplets on the surface of the plastic wrap. All three samples shall comply with the requirements of 4.5 of this standard. 5.9 Determination of hygienic indicators
shall be carried out in accordance with the provisions of GBn84.
6 Inspection Rules
6.1 Inspection Categories
6.1.1 Factory Inspection
6.1.1.1 The specifications, dimensions and appearance of plastic wrap should be sampled and inspected batch by batch. 6.1.1.2 The tensile strength, elongation at break, right-angle tear strength, unwinding property, anti-fogging property and self-adhesiveness of the cling film shall be tested from at least one roll of 61
for each batch.
6.1.2 Type inspection
GB 10457-89
6.1.2.1 Carry out sampling inspection according to all technical requirements specified in the standard, at least once every six months. 6.1.2.2 When changes in formula, production process or raw materials may affect product performance, type inspection should be carried out at any time. 6.2 Sampling, batching and judgment rules
6.2.1 Every 10,000 rolls of products are considered to be one batch. Those with less than 10,000 rolls in stock will also be treated as one batch. Randomly select 10 rolls from each batch of products for specification and appearance inspection. 6.2.2
Take any one roll from each batch of products for inspection of physical and mechanical properties, unwinding properties, anti-fog properties and hygienic indicators. 6.2.31
6.2.4 Judgment rules:
6.2.4.1 Specifications and appearance. If any one of them fails to meet the standard requirements, the product will be unqualified. If the pass rate of 10 rolls of products reaches more than 90%, the batch of products is qualified. Otherwise, double the number of samples should be taken for re-inspection. If the pass rate reaches more than 90%, the batch of products is qualified, otherwise it is unqualified.
6.2.4.2 If any of the physical and mechanical properties, unwinding properties, and anti-fog properties are unqualified, double the number of samples should be taken from the original batch to re-inspect the unqualified items. The re-inspection results shall meet the standards. When required, the batch of products is qualified, otherwise it is unqualified. 6.2.4.3 Hygiene indicators, if any one of them fails, the batch of products will be unqualified. 7 Marking, packaging, transportation and storage
7.1 Mark
The product name, quantity, specification, manufacturer name and valid period of use should be marked on the inner packaging box and bag, and the outer packaging mark complies with GB6388 Regulation.
7.2 Packaging
7.2.1 Inner packaging
Simple packaging - polyethylene plastic bag.
Hardcover with small rack carton.
Special hardcover plastic box with rack.
7.2.2 Outer packaging
Products should be packaged in corrugated cartons that comply with the requirements of GB6543. 7.3 Transportation
Products should be protected from moisture and sun during transportation. During loading and unloading, they should be lifted and placed gently without heavy pressure. 7.4 Storage
Products should be stored in a clean, cool, dry warehouse and should not be in contact with corrosive chemicals and other harmful substances. The distance from the heat source is not less than 1m.
Additional notes:
This standard is under the jurisdiction of the Department of Science and Education of China Packaging Corporation. This standard is drafted by the Shandong Provincial Product Quality Supervision and Inspection Institute. The participating units in drafting this standard are Shanghai Plastic Products Research Institute and Foshan Leather and Plastic Research Institute of Guangdong Province. The main drafters of this standard are Zhang Chengzhi, Jiao Yi and Song Yaguang. 62
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