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GB/T 24451-2020: Low resilience flexible polyurethane cellular plastics
Status: Valid GB/T 24451: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Standard Title (Description) | Status | PDF |
| GB/T 24451-2020 | English | 259 |
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Low resilience flexible polyurethane cellular plastics
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GB/T 24451-2020
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| GB/T 24451-2009 | English | 559 |
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Low resilience flexible polyether polyurethane cellular plastics
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GB/T 24451-2009
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PDF similar to GB/T 24451-2020
Basic data | Standard ID | GB/T 24451-2020 (GB/T24451-2020) | | Description (Translated English) | Low resilience flexible polyurethane cellular plastics | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | G32 | | Classification of International Standard | 83.100 | | Word Count Estimation | 14,155 | | Date of Issue | 2020-07-21 | | Date of Implementation | 2021-02-01 | | Older Standard (superseded by this standard) | GB/T 24451-2009 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | GB/T 24451-2020: Low resilience flexible polyurethane cellular plastics---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Low resilience flexible polyurethane cellular plastics
ICS 83.100
G32
National Standards of People's Republic of China
Replacing GB/T 24451-2009
Slow rebound flexible polyurethane foam
Published on 2020-07-21
2021-02-01 Implementation
State Administration for Market Regulation
Released by the National Standardization Administration
Slow rebound flexible polyurethane foam
1 Scope
This standard specifies the classification, requirements, test methods, inspection rules and marking, packaging, transportation,
storage.
This standard applies to block, sheet and strip or cut-and-formed slow-resilient flexible polyurethane foams obtained by free foaming.
A slow-rebound flexible polyurethane foam made by molding.
2 Normative references
The following documents are essential for the application of this document. For dated references, only the dated version applies to this article
pieces. For undated references, the latest edition (including all amendments) applies to this document.
GB/T 531.1-2008 Test method for indentation hardness of vulcanized or thermoplastic rubber - Part 1.Shore durometer method (Shore
hardness)
GB/T 2918-2018 Standard Environment for Conditioning and Testing of Plastic Samples
GB/T 6342-1996 Determination of Linear Dimensions of Foamed Plastics and Rubber
GB/T 6343-2009 Determination of Apparent Density of Foamed Plastics and Rubber
GB/T 6344-2008 Determination of tensile strength and elongation at break of flexible foamed polymeric materials
GB/T 6669-2008 Determination of compression set of flexible foamed polymeric materials
GB/T 6670-2008 Determination of resilience performance of flexible foamed polymeric materials by falling ball method
GB/T 9345.1-2008 Determination of ash content of plastics - Part 1.General method
GB/T 9640-2008 Test method for accelerated aging of flexible and rigid foamed polymeric materials
GB/T 10807-2006 Determination of hardness of flexible foamed polymeric materials (indentation method)
GB/T 10808-2006 Determination of tear strength of polymeric porous elastic materials
GB/T 26392-2011 Determination of recovery time of slow rebound foam
QB/T 2819-2006 Determination of long-term fatigue properties of soft polymeric materials
QC/T 850-2011 Polyurethane foam for passenger car seats
3 Terms and Definitions
The following terms and definitions apply to this document.
3.1
A polyurethane foam with slow recovery, low rebound and high hysteresis loss characteristics.
4 Classification and Grading
4.1 Classification
4.1.1 According to the production process, it is divided into block slow-rebound flexible polyurethane foam (Type B) and molded slow-rebound flexible polyurethane foam (M
6 Test methods
6.1 Sampling requirements and state adjustment
The test was carried out after being placed under natural conditions for 72 hours from the date of product production. Slab foam specimens to be skin removed; molded foam
When the physical properties of plastics are tested in 5.4, 5.5 and 5.6, the skin of the sample shall be removed.
The test is carried out according to the 23/50 secondary environmental conditions in GB/T 2918-2018.
Under the condition of 10)%, the state adjustment shall be carried out for no less than 16h.
6.2 Limit deviation of length, width and thickness
6.2.1 The limit deviation of length and width shall be carried out according to the provisions of GB/T 6342-1996.Use a tape measure with a minimum division of 1mm to measure the length,
There are 3 values for each width, the length and width dimensional deviations are calculated, and the number of samples is 3.
6.2.2 The thickness limit deviation shall be carried out according to the provisions of GB/T 6342-1996.Measure the thickness with a measuring tool with an accuracy of 0.1mm, in the distance from the width
Start measuring 30mm away from the edge and 80mm away from the edge in the length direction, with no less than 5 measurement points, measure the thickness value, and calculate the thickness.
Degree deviation, the number of samples is 3.
6.3 Appearance
6.3.1 Visual inspection of color and stains under normal light.
6.3.2 The pores are measured with a measuring tool with an accuracy of 0.5mm, and the crack length is measured with a tape measure with a minimum graduation value of 1mm.
6.4 Apparent Density Deviation
The apparent core density is tested according to the provisions of GB/T 6343-2009, the apparent density deviation is calculated, the number of samples is 3, and the sample size is
(50±1)mm×(50±1)mm×(50±1)mm.
6.5 Indentation hardness
Carry out according to the provisions of GB/T 10807-2006 Method B. Test the 40% indentation hardness and the ratio of 65% to 25% indentation hardness.
6.6 Recovery time
According to the provisions of GB/T 26392-2011, the number of samples is 1.
6.7 75% compression set
According to the provisions of GB/T 6669-2008 Method A, the number of samples is 5, and the sample size is (50 ± 1) mm × (50 ± 1) mm ×
(25±1)mm. The test temperature is (70 ± 2) ℃, the test time is 22h, and the compression sample is 75% of the thickness (compressed to 25% of the original thickness of the sample).
6.8 Rebound rate
According to the provisions of GB/T 6670-2008 Method B, the number of samples is 3, and the sample size is (100 ± 3) mm × (100 ± 3) mm ×
(50±2)mm.
6.9 Tensile strength and elongation
According to the provisions of GB/T 6344-2008, the number of samples is 5, the thickness of the sample is 10mm~15mm, and the test speed is (500±50)
mm/min, effective gauge length 50mm.
6.10 Tear strength
According to the provisions of GB/T 10808-2006, the number of samples is 5, and the test speed is.200mm/min.
6.11 Odour class
The odor level is carried out according to the provisions of Appendix B in QC/T 850-2011.
6.12 Tensile strength change rate after dry heat aging
Carry out according to the provisions of GB/T 9640-2008.
The test temperature is 140 ℃, and after standing for 16 hours, the tensile strength is measured according to 6.9, and the change rate of the tensile strength after dry heat aging is calculated.
6.13 Change rate of tensile strength after damp heat aging
Carry out according to the provisions of GB/T 9640-2008.
The test temperature is 105°C and 100% relative humidity or supersaturated steam for 3 hours, and then the tensile strength is tested according to 6.9, and the humidity is calculated.
Tensile strength change rate after heat aging.
6.14 Determination of 40% indentation hardness loss rate after repeated indentation fatigue under constant load
Carry out according to the regulations of QB/T 2819-2006.
6.15 Ash
Carry out according to the provisions of GB T9345.1-2008 Method A.
The test temperature is 725 ℃, and the residue is until constant weight, but the calcination time at the specified temperature should not exceed 3h.
6.16 Formaldehyde emission
According to the test method of A.3 formaldehyde emission in QC/T 850-2011.
6.17 Temperature and Humidity Sensitivity Index
Carry out the test method in Appendix B.
7 Inspection rules
7.1 Inspection classification
7.1.1 Factory inspection
The factory inspection items are 5.1, 5.2, 5.3, 5.4, 5.5 and recovery time, rebound rate, tensile strength, and elongation in Table 8.
7.1.2 Type inspection
Type inspection is all items in Chapter 5.Type inspection should be carried out in one of the following situations.
a) Type identification for trial production of new products;
b) After the formal production, if there are major changes in the structure, raw materials and processes, which may affect the performance of the product;
c) An inspection is carried out every six months during normal production;
d) When the product resumes production after a long-term shutdown for half a year;
e) When there is a big difference between the factory inspection results and the last type inspection results.
7.2 Batching and Sampling
7.2.1 Batch
The same raw material, the same formula, the same process conditions, the continuous production quantity does not exceed 50t as a batch, and the box-type production quantity does not exceed 10t
for a batch.
7.2.2 Sampling
Dimensional deviation and appearance 3 pieces of products are randomly selected from each batch for inspection, and physical properties are randomly sampled from the middle of the sample for inspection.
7.3 Judgment Rules
7.3.1 Dimensional deviation and appearance If three samples are randomly selected from the product and all are qualified, the size and appearance of the batch are qualified. one of the pieces
When any one of the samples fails, take 3 samples again for testing, all 3 samples are qualified, and the test results are judged to be qualified, if one sample is not qualified
, and the test result is judged to be unqualified.
7.3.2 If any one of the physical properties fails to pass, double sampling shall be taken from the original batch, and the unqualified items shall be re-inspected, and the results of the re-inspection shall be carried out.
All qualified, the inspection item is qualified. If the re-inspection result is still unqualified, the batch is considered unqualified.
7.3.3 If the size, appearance and physical properties are all qualified, the batch of products is qualified.
8 Marking, packaging, transportation and storage
8.1 Logo
The product should have a certificate of conformity. Product identification should include name, trademark, specification, model, color, production date, batch number, manufacturer name, production
Factory address, inspector seal and standard number, etc.
8.2 Packaging
Products can be packaged in plastic bags, woven bags, etc.
8.3 Transport
The product is strictly prohibited from fireworks during transportation, to prevent sunlight and rain, and to avoid long-term pressure and mechanical damage.
8.4 Storage
Products should be stored in a clean, ventilated and dry warehouse, away from heat sources, and should not be in contact with chemicals.
Appendix A
(informative appendix)
Categories and suggested application areas
Slow-rebound flexible polyurethane foams are classified into five categories. X, V, S, A, and L according to their final use. See Table A.1 for their classification and application fields.
Table A.1 Categories and suggested application areas
Category Application Field
X Continuous use of heavy-duty cushions in public places, public transport cushions and similar uses
Vehicle driver seat cushions, theater or theater seat cushions, public transport seat cushions, public and office seat cushions, mattresses and the like
Similar use
Passenger seat cushions for private or commercial vehicles, home cushions, backrests and armrests for public and office seats, backrests and armrests for theater or theater seats
Hands, backrests, armrests and similar uses of public transport seats
A Backrests, armrests of private and commercial vehicle seats, backrests, armrests and similar uses of household seats
L Padded cushions, back cushions, pillows, neck pillows, other pillow cushions, earplugs and similar uses
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