This standard replaces GB/T8168-1987 "Static Compression Test Method for Packaging Cushioning Materials". This standard specifies the test principle, test equipment, test samples, test procedures and test reports of the static compression test method for packaging cushioning materials. This standard is applicable to the evaluation of the cushioning performance of cushioning materials under static load and their ability to protect the products contained in the packaging during circulation. The packaging cushioning materials applicable to this standard may be in the form of blocks, sheets, filaments, granules and molded parts, such as EPS, EPE and other soft and hard cushioning materials, but not corrugated paperboard, EPE film, metal springs and shockproof rubber. Compared with GB/T8168-1987, this standard has the following major changes: - Added references, terms and test equipment; - Added requirements for random sampling of test samples; - Modified the number of test samples for the test; - Added the recommended size specifications of test samples; - Added the provisions for the load applied in test method B; - Added the requirements for the test thickness measurement value in the test data. GB/T 8168-2008 Static Compression Test Method for Packaging Cushioning Materials GB/T8168-2008 Standard download decompression password: www.bzxz.net
This standard specifies the test principle, test equipment, test samples, test procedures and test reports of the static compression test method for packaging cushioning materials. This standard is applicable to the assessment of the cushioning performance of cushioning materials under static loads and their ability to protect the products contained in the circulation process. The packaging cushioning materials applicable to this standard may be in the form of blocks, sheets, filaments, granules and molded parts, such as EPS, EPE and other soft and hard cushioning materials, but are not applicable to corrugated cardboard, EPE film, metal springs and shockproof rubber.
This standard replaces GB/T8168-1987 "Static Compression Test Method for Packaging Cushioning Materials".
Compared with GB/T8168-1987, the main changes of this standard are as follows:
--- Added the referenced documents, terms and test equipment;
--- Added the requirements for random sampling of test samples;
--- Modified the number of test samples for the test;
--- Added the size specifications of the recommended test samples;
--- Added the provisions for the load applied to the B test method;
--- Added the requirements for the test thickness measurement value in the test data.
Appendix A of this standard is an informative appendix.
This standard is proposed and managed by the National Packaging Standardization Technical Committee (SAC/TC49).
The drafting units of this standard are: China Machinery Productivity Promotion Center, Shenzhen Meiyingsen Environmental Protection Technology Co., Ltd., and China Export Commodity Packaging Research Institute.
The main drafters of this standard are: Huang Xue, Liu Ping, Cai Shaoling, Li Jianhua, Zhang Xiaojian, and Ding Jiayi.
The previous versions of the standards replaced by this standard are:
---GB/T8168-1987.
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version shall apply to this standard.
GB/T4122.1 Packaging terms Part 1: Basics
GB/T4857.2 Basic tests for packaging and transport packages Part 2: Temperature and humidity conditioning treatment (GB/T4857.2-2005, ISO2233:2000, MOD)

ICS55.040
National Standard of the People's Republic of China
GB/T8168—2008
Replaces GB/T8168-1987
Testing method of static compression forpackaging cushioning materials2008-06-10 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of ChinaStandardization Administration of the People's Republic of China
Implemented on 2009-01-01
This standard replaces GB/T8168—1987 "Testing method of static compression forpackaging cushioning materials". Compared with GB/T8168-1987, this standard has the following major changes: added references, terms, and test equipment; added requirements for random sampling of test samples; modified the number of test samples for testing; added recommended size specifications for test samples; added provisions for the load applied in test method B; and added requirements for test thickness measurement values ​​in test data. Appendix A of this standard is an informative appendix.
This standard is proposed and managed by the National Packaging Standardization Technical Committee (SAC/TC49). GB/T8168—2008
The drafting units of this standard are: China Machinery Productivity Promotion Center, Shenzhen Meiyingsen Environmental Protection Technology Co., Ltd., and China Export Commodity Packaging Research Institute.
The main drafters of this standard are: Huang Xue, Liu Ping, Cai Shaoling, Li Jianhua, Zhang Xiaojian, and Ding Jiayi. The previous versions of the standards replaced by this standard are: -GB/T8168--1987.
1 Scope
Static compression test method for cushioning materials for packaging GB/T8168--2008
This standard specifies the test principle, test equipment, test samples, test procedures and test reports of the static compression test method for cushioning materials for packaging.
This standard is applicable to the evaluation of the cushioning performance of cushioning materials under static loads and their ability to protect the products contained in them during circulation.
The shape of cushioning materials for packaging applicable to this standard can be soft and hard cushioning materials such as EPS and EPE in the form of blocks, sheets, filaments, granules and molded parts. It does not apply to corrugated cardboard, EPE film, metal springs and shockproof rubber. 2 Normative references
The clauses in the following documents become clauses of this standard through reference in this standard. For all dated references, all subsequent amendments (excluding outdated content) or revisions are not applicable to this standard. However, parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated references, the latest versions shall apply to this standard. GB/T4122.1 Packaging terms Part 1: Basics GB/T4857.2 Packaging and transport Basic tests for packages Part 2: Temperature and humidity conditioning (GB/T4857.2-2005, ISO2233:2000, MOD)
3 Terms and definitions
The terms and definitions established in GB/T4122.1 and the following terms and definitions apply to this standard. 3.1
Thickness reduction ratethicknessdecreaserateThe percentage of thickness reduction of the specimen caused by repeated short-term application of compressive load. 3.2
Static compression residual strain
static compression residual strainThe state of removing the load after applying stress for a certain period of time, expressed as thickness reduction rate. 4 Test principle
The method of applying a compressive load at a low speed on the cushioning material for packaging is used to obtain the compression stress-compression strain curve of the cushioning material. 5 Test equipment
5.1 Test machine
5.1.1 The base of the test machine should have sufficient rigidity. 5.1.2 The test machine should have a test platen with adjustable pressure load. 5.2 Test data control equipment
The value of the applied pressure load and the pressure speed are adjusted through the output device. GB/T8168—2008
6 Test samples
6.1 Sampling
The test samples should be randomly selected from the finished products that have been placed for more than 24 hours. When their dimensions cannot meet the specified requirements, it is allowed to manufacture the test samples under the same conditions as the production conditions. 6.2 Size
The test sample is a regular rectangular cube. The area of ​​the upper and lower bottoms is at least 100mm×100mm. If conditions permit, it is recommended to select test samples with an upper and lower bottom area of ​​200mm×200mm. The thickness of the test sample should not be less than 25mm (when the thickness is less than 25mm, it is allowed to be stacked). When the test material is in the form of thin flakes or particles, a compression box (see Appendix A) can be used for testing. Its area is 150mm×150mm and the thickness is more than 100mm. 6.3 Quantity
The number of test samples is generally selected according to the accuracy required for the test results and the material of the test samples. The number of test samples in a group should be no less than 3.
6.4 Measurement
6.4.1 Measuring plate for length and width
Measure the dimensions of the two ends and the three positions in the middle along the length and width direction of the test sample respectively with a measuring tool with a minimum division value of no more than 0.05mm, and calculate the average value respectively, and the accuracy is 0.1mm. 6.4.2 Measurement of thickness
Place a rigid flat plate on the upper surface of the test sample so that the test sample is subjected to a compression load of 0.20kPa±0.02kPa. After 30s, under load, measure the thickness of the four corners with a measuring tool with a minimum graduation value of no more than 0.05mm, calculate the average value, and be accurate to 0.1mm.
When measuring the size of test samples such as filaments and granules, a compression box should be used for measurement. 6.4.3 Density measurement
a) Weigh the mass of the test sample with a balance with a sensitivity of more than 0.01g, and record the measured value. b) Calculate the density of the test sample according to formula (1): m
P=LIXL,XT
Where:
density of the test sample, in grams per cubic millimeter (g/mm); mass of the test sample, in grams (g);
length of the test sample, in millimeters (mm); L
-width of the test sample, in millimeters (mm); T
thickness of the test sample, in millimeters (mm). 7 Test procedure
Pretreatment of test samples
Before the test, select a condition according to GB/T4857.2 to pretreat the test samples for more than 24 hours. 7.2 Temperature and humidity conditions during the test
-(1)
The test should be carried out under the same temperature and humidity conditions as the pretreatment. If the same conditions cannot be achieved, the test should be carried out under the same conditions as possible.
7.3 Test steps
7.3.1 Method A
7.3.1.1 Before the test, measure the thickness of the test sample and use it as the original thickness (T) of the test. 2
GB/T8168—2008
7.3.1.2 The pressure plate gradually increases the load on the test sample along the thickness direction at a speed of 12mm/min±3mm/min. During the compression process, the compression force and the corresponding deformation are recorded simultaneously. The strain corresponding to the load is recorded by an automatic recording device or at least 10 points are measured to draw a compression stress-compression strain curve. 7.3.1.3 Stop the test when the compression load increases sharply. 3 minutes after the load is removed, measure the thickness of the test sample according to the method of 6.4.2, and use it as the thickness of the test sample after the test (T,). 7.3.2 Method B
7.3.2.1 Before the test, measure the thickness of the test sample and use it as the original thickness of the test (T). 7.3.2.2 Repeatedly compress the test sample 10 times with a deformation load of 20% of the test sample thickness. 30 minutes after the load is removed, measure the thickness of the test sample according to the method of 6.4.2, and use it as the pre-compression thickness of the test sample (T,). This time is used as the deformation origin of the compression test. 7.3.2.3 After the pre-compression test, test according to 7.3.1.2 to 7.1.1.3. 7.4 Calculation
7.4.1 Compressive stress
The calculation of compressive stress is shown in formula (2):
Where:
-compressive stress, in Pascals (Pa);
P--compressive load, in Newton (N);
A-bearing area of ​​the test sample, in square millimeters (mm). 7.4.2 Compressive strain
7.4.2.1 Compressive strain in method A test
The calculation of compressive strain in method A is shown in formula (3):E
Where:
e.Compression strain in method A test, %;
T—Original thickness of the test sample, in millimeters (mm); TT
T—Thickness of the test sample after the test, in millimeters (mm). 7.4.2.2 Compression strain in method B test
The calculation of compression strain in method B is shown in formula (4): Eh
Where:
Eb—Compression strain in method B test, %;
Thickness of the test sample after pre-compression, in millimeters (mm). 7.4.3 Thickness reduction rate (the thickness reduction rate must be indicated in the test report for method B) The calculation of thickness reduction rate in method B is shown in formula (5): TT.
Where: wwW.bzxz.Net
AT—Thickness reduction rate, %;
—Original thickness of the test sample, in millimeters (mm); Thickness of the test sample after pre-compression, in millimeters (mm). (2)
·(3)
(4)
·(5)
GB/T8168—2008
7.4.4 Static compressive residual strain
The calculation of static compressive residual strain is shown in formula (6): Where:
Static compressive residual strain, %;
Original thickness of the test sample, in millimeters (mm); TT
T—Thickness of the test sample after compression test, in millimeters (mm). 8
Test report
The test report shall include the following contents:
(6)
Detailed description of the test sample, such as the name, type, shape, size, density, manufacturer, brand, date of manufacture, etc. of the material;a
Number of test samples;
Pretreatment conditions of the test samples;
Temperature and humidity conditions during the test;
Relevant description of the test equipment;
Test method (method A or method B);
Thickness measurement values ​​of the test samples before and after the test; Compression stress (o)-compression strain (e) curve of each test sample;h)
When method B is used for testing, the thickness reduction rate of the test sample; Compression residual strain after compression test;
Description of the differences between the test method used and this standard; Other detailed records and descriptions;
Test date, signature of the test personnel and seal of the testing unit. m)
Appendix A
(Informative Appendix)
Compression box
GB/T8168—2008
The shape and dimensions of the compression box are shown in Figure A1. The compression box should have sufficient rigidity and should not deform due to the applied load. Inner box
Schematic diagram of the compression box structure
GB/T8168-2008
People's Republic of China
National Standard
Static compression test method for cushioning materials for packaging GB/T8168—2008
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