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Molded Polyurethane Industry Panel Recommend Specification
July, 2008
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| CELLULAR - MOLDED POLYURETHANE - HIGH RESILIENT (HR) TYPE - SEAT APPLICATIONS |
| 1.0 GENERAL |
| 1.1 Purpose |
| This standard states the requirements of flexible, open celled, molded polyurethane foam for cushioning applications. This material is a high resilience (HR) or resilient polyurethane foam, which provides good dynamic and static comfort in seating applications. In addition, this material has good durability performance characteristics. |
| 1.2 Coverage of this Standard/Form Designations |
| The materials listed in this standard are recommended for use in seating applications, excluding headrests/armrests. These standards are to be considered minimum compliance. Optimum seat conditions for maximum comfort and durability may require values different than those shown in the specification below, but this will be program and part specific. |
| 1.3 Location of Abbreviations/Acronyms/ Definitions |
| Abbreviations/Acronyms/ Definitions can be found in Section 5.0 toward the end of this standard. |
| 2.0 MATERIAL CHARACTERISTICS |
| All test samples shall be crushed at demold in a manner that is consistent with production intent. They shall be cured for at least the minimum time period specified in the control plan prior to hardness testing and a provision shall exist to correlate the short-term IFD values to a fully cured sample. PPAP samples shall be cured for a minimum of 7 days prior to all other physical property testing. The samples must be conditioned in the lab environment, 23 + 2 C and 50 + 5% RH, for a minimum of 12 hours prior to testing. |
| Except where noted, all tests shall be performed on core specimens cut at a minimum of 10 mm below the molded surface of the sample and they shall have their longest dimension at right angles to the direction of the foam rise. This will place that dimension parallel to the top surface. Specimens shall be taken from in and around the IFD circle and they shall be free of densification layers or any portion where there is an obvious defect, such as voids. These statements supercede the specimen preparation instructions contained in the methods that exist outside of this document. |
| This specification segments polyurethane seating material into four types. As the type number decreases the material performance level increases. This segmentation allows the engineer to apply the proper performance level, based on part functionality, for all seating positions within an automobile. The four types are based on material performance and they do not address the actual part design, particularly thickness. The seat engineer must consider the function, design, and usage level of the part and select the proper type based on the seating application. Reference Appendix B: Design Guidelines for the Use/Application of Polyurethane Foam in Automotive Seating. |
| The properties in Table I are representative of typical foam pads. Atypical applications such as reduced thickness, suspension type, contour, aggressive bolsters, and field use may require increased requirements in Section 3.2 . |
| If any of the physical properties listed in this standard are not met due to design restrictions, those requirements shall be addressed with a print deviation provided all functional seat requirements are met. |
| The material covered by this specification shall have no objectionable odor. If a method is required to resolve a disagreement between a customer and supplier on a potential odor issue, SAE J1351 shall be used to evaluate the perceived odor level. |
| The trim surface of molded urethane foam pads shall have a uniform finish and texture. The pad may contain slight blemishes, which do not interfere with or show through the trimmed part. |
| Molded urethane foam pads shall not have internal fissures, pockets of collapsed foam or voids, unreacted chemicals, embedded foreign matter, or surface incrustation created by abnormal cell formations that interfere with the function or appearance of the trimmed parts. |
| Experimental and program parts made with these materials shall be representative of production. They shall be uniform in texture, finish and physical properties |
| Residual parting agent on the surface of molded urethane foam pads shall not contribute to contamination, fading, or discoloration of the trim material used over it. |
| This material is susceptible to set damage when exposed to steam. Use of excessive steam in the seat assembly process can damage polyurethane flexible foam. Assembly plant steaming practices shall be reviewed before releasing parts using this material. |
| 2.1 ALTERNATE MATERIALS |
| Renewable content polyurethane materials may be used to produce parts for this specification. Prior to using a renewable content material to mold a finished seating product, the supplier shall provide data showing that it meets the requirements contained within this specification. In addition to the requirements listed in Table I, odor results, per SAE J1351, must be submitted for initial material approval. |
| 3.0 MATERIAL PERFORMANCE REQUIREMENTS |
| 3.1 Material Source Approval |
| Engineering qualification of an approved source is not required for this specification. To prove conformance, all sources supplying products to this specification must provide data to materials engineering and at PPAP. |
| Refer to Table 1 for the Mechanical and Physical Property Requirements. |
| Specimens shall be obtained from molded parts unless noted otherwise. If part thickness or configuration makes it too difficult to obtain usable test specimens, surrogate test blocks molded from the same material shall be used. |
TABLE 1: REQUIREMENTS FOR POLYURETHANE SEATING FOAM
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TYPE I
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TYPE II
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TYPE III
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TYPE IV
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Core Density, kg/m3, Min
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56
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48
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40
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32
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Indentation Force Deflection (IFD), N
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Per Engineering Drawing With Tolerance
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Load Indentation (Bolster Hardness), N
(Dual Firmness / Dual Density Parts Only)
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Per Engineering Drawing With Tolerance
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Hysteresis Loss, % Loss, Max
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23
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25
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30
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35
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Tear Resistance, N/m, Min
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500
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450
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450
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450
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Wet Compression Set, % loss, Max
(% of Original Thickness)
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12
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15
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20
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25
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Wet Age CFD Change (50%), %, Max ( + )
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20
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20
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20
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20
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Constant Force Pounding
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Height Loss, %, Max
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3
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4
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4
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6
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IFD Loss, (40% deflection), %, Max
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15
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15
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20
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25
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Staining, Delta E Change
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Difference of 20 or less
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Fogging, min
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70, Oily droplets, crystals, or opaque film may be cause for rejection (1)
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Burn Rate, mm/minute, Max (2)
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100
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| NOTE 1: Fogging Plate Observations: Visual record using naked eye or optical microscope (preferred). Microphotographic record of any plate deposits especially recommended for record retention and for discussions between customer and foam manufacturers. |
| NOTE 2: The burn rate requirement in Table 1 is only applicable if FMVSS 302 is called-out on the engineering drawing. Any supplier who provides material or components to this standard must perform lot control testing, maintain material traceability, and keep appropriate records as specified in the applicable quality OEM standards. |
| 3.3 Methods of Testing |
| Refer to Table 2 for the Methods of Testing. |
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TABLE 2: METHODS FOR TESTING POLYURETHANE SEATING FOAM
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TEST
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PROCEDURE
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Core Density
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ASTM D 3574, Test A / ISO 845 (Note 3)
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Indentation Force Deflection (IFD): 50% Deflection
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ASTM D 3574, Test B1 / ISO 2439 (Note 3)
IFD Test Method must be noted on the Engineering Drawing
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Force Indentation (Bolster Hardness)
- Test Molded Part
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(See Appendix A – Supplemental Test Methods)
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Hysteresis Loss
- 380 x 380 x 100 mm Molded Test Block.
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ASTM D 3574, Appendix X6, Procedure A
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Tear Resistance
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ASTM D 624, Die C : Test specimen thickness shall be 10 + 1 mm. / ISO 34 (Note 3)
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Wet Compression Set: 50% Deflection
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ASTM D 3574, Test D, L (Ct Calculation)
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Wet Age CFD Change: 50% Deflection
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ASTM D 3574, Test C, L
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Constant Force Pounding
- specimen cut from a 380x380x100 mm molded test block, which includes top molded surface
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ASTM D 3574, Test I3, Procedure B / ISO 3385 (Note 3)
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Staining
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See Appendix A – Supplemental Test Methods
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Fogging, max
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SAE J1756, 3h at 100C Heating, 40C Cooling, Evaluate 1 and 24 h
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Burn Rate <S>
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ASTM D 5132 / ISO 3795 (Note 3)
This test is strictly a screening method for categorizing the material's ability to resist burning. Materials, which exceed a 100mm/min burn rate, may or may not meet burn rate requirements once it is assembled as a finished part. Therefore, it is usually wise to select materials that have lower burn rates for applications that are required to meet the government flammability standard.
NOTE: FMVSS-302 is used for interior parts, which are required to meet the maximum burn rate of 100 mm/min. Flammability testing should always be done on full part construction of released end items, and not on test plaques to verify compliance.
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| Functional Life: Parts manufactured from this material shall perform satisfactorily in seat assemblies subjected to proving grounds service life, laboratory fatigue life tests, and meet current warranty specifications. |
| Note 3: The ISO and ASTM test methods are similar, but there are technical differences, particularly with IFD. For this reason the IFD test method must be noted on the engineering drawing. |
| 3.4 Load Test Fixture (LTF) Design Guidelines |
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The load test fixture shall be manufactured of a stable material that does not deflect under testing parameters. |
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The target weight of the LTF should be less than 10 kg due to ergonomic considerations (not always possible) |
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The LTF shall conform to the B-surface of the pad and shall be positively located |
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All vertical surfaces shall have a 2 mm clearance for ease of pad installation and removal |
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The resulting A-surface of the pad on the LTF shall be parallel to the UTM table with a +/-5 degree tolerance in the identified IFD testing zone |
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Long pads shall be supported to avoid cantilevering of the pad |
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The pad shall not touch the table of the UTM |
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The LTF shall be pinned to ensure the test foot coincides with the compression foot circle identified on the part. |
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If pad is dual density/hardness a locating plate to test the wings for indent is required. |
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LTF should be identified with the part number, ECN/date, supplier name |
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Should have at least one handle |
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Shall be CNC cut to Math data |
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| 4.0 OEM Requirements |
| 4.1 Annual Certification of Material |
| Annual Certification to this standard shall require continued conformance testing to all original physical property requirements within this standard or associated engineering drawing. The primary OEM supplier shall hold annual material certifications on file. |
| 4.2 Additional Requirements |
| Typical requirements include: Adhesives, components, repairs, part identification, etc. Refer to applicable OEM documents for additional approval guidelines. |
| 4.3 Quality |
| Must conform to the general material characteristics as outlined in the appropriate OEM appearance/quality standards. |
| 5.0 ABBREVIATIONS/ACRONYMS/ DEFINITIONS |
| 5.1 Abbreviations/Acronyms |
ASTM, American Society for Testing and Materials International
C, Degrees Celsius
CFD, Compression Force Deflection
CFR, Code of Federal Regulations
CNC, Computer Numerically Controlled
ECN, Engineering Change Number
FMVSS, Federal Motor Vehicle Safety Standard
h, hour
HR, High Resilience
IFD, Indentation Force Deflection
ISO, International Standards Organization
LTF, Load Test Fixture
N/m, Newton per meter
m, meter
max, maximum
min, minimum
mm, millimeter
N, Newton
OEM, Original Equipment Manufacturer
PPAP, Production Part Approval Process
RH, Relative Humidity
SAE. Society of Automotive Engineers
UTM, Universal Testing Machine
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| 5.2 Definitions |
| A-Surface: The surface of the pad that is in contact with the trim cover. |
| B-Surface: The non-exposed surface, bottom of a molded foam pad. |
| Cells: The individual cavities in the skeletal structure of the foam formed by the nucleation and growth of bubbles within the reacting liquid. |
| Cellular Material: A material composed of a multitude of interconnecting cells. |
| CFD (Compression Force Deflection): A measure of the load bearing ability of a foam. It is the pressure exerted against a flat compression foot larger than the specimen to be tested. The value can be expressed at 25%, 40%, 50%, and/or 65% compression (ASTM D3574). Note: previously called "CLD" (Compression Load Deflection). |
| CFD Change: The change in hardness of a foam specimen, expressed as a percentage of the original force measured at 50% compression, after the specimen is subjected to accelerated aging. |
| Compression Set: A permanent partial loss of initial height of a flexible polyurethane foam sample after compression due to a bending or collapse of the cellular framework within the foam sample. A high value of compression set will cause a flexible polyurethane foam cushion to quickly lose its original appearance with use, leaving its surface depressed or "hollowed out". Compression set is measured in the lab by compressing a foam sample 50% of its thickness (or down to 50% of its original thickness) and holding it at elevated temperature and/or humidity. Compression set is most commonly expressed as a percentage of original thickness. Other deflections, times, and temperatures can be used. |
| Constant Force Pounding: A fatigue test that measures (1) the loss of force support at 40% IFD (2) a loss in thickness, and (3) structural break down as assessed by visual inspection. |
| Core: The internal portion of foam, free of any skin. |
| Core Density: The density of the foam sampled without skin, glue lines or compressed sections at or near the center of the final foamed shap |
| Cure: A term referring to the process whereby the urethane chemical reaction approaches completion. At 100% completion, a foam should have 100% of the physical properties attainable with that particular formulation. |
| Density: A measurement of the mass per unit volume. It is measured and expressed in kilograms per cubic meter (kg/m3). |
| Dual Density or Firmness Pad: A foam pad that is molded with one density or firmness foam in the main body of the pad and higher density or firmness foam in the bolsters. |
| Fatigue: A softening or loss of firmness/thickness. Fatigue can be measured in the laboratory by repeatedly compressing a foam sample and measuring the change in IFD and thickness. |
| HR (High Resilience): A variety of polyurethane foam produced using a blend of polymer or graft polyols. High resilience foam has a less uniform (more random) cell structure different from conventional products. The different cell structure helps add support, comfort, and resiliency or bounce. High resilience foams have a high support factor and greater surface resilience than conventional foams and are defined in ASTM D3453. |
| Hysteresis Loss: This test measures foam resiliency by determining energy loss during loading and unloading of the sample. Low hysteresis loss equates to higher resiliency foam. |
| IFD (Indentation Force Deflection): A measure of the load bearing capacity of flexible polyurethane foam. IFD is generally measured as the force (in Newtons) required to compress a 324 square cm circular indentor foot into a part or block sample, to a stated percentage of the sample's initial height. Common IFD values are generated at 25, 50, and 65 percent of initial height. Note: Previously called "ILD" (Indentation Load Deflection). |
| Molded Foam: A cellular foam product having the shape of the mold cavity in which it was produced. |
| Open Cell Structure: A permeable structure in flexible foam in which there is no barrier between cells, and gases or liquids can pass through the foam. Most cell walls have been ruptured to varying extent. |
| Polyurethane Foam: A flexible cellular product produced by the interaction of active hydrogen compounds, water, and isocyantes. |
| Recycled Content. The portion of a material's or product's weight that is composed of materials that have been recovered from or otherwise diverted from the waste stream either during the manufacturing process [pre-consumer/post-industrial] or after consumer use [post consumer]. |
| Renewable Content Foam: Polyurethane seating pads that are manufactured with a foam chemistry where a portion of the petroleum based component is displaced by natural oil-based derivatives. |
| Resilience: An indicator of the elasticity or "springiness" of foam. It is measured by dropping a steel ball onto the foam sample/cushion and measuring how high the ball rebounds. |
| Skin: The smooth surface layer of a molded foam product, formed when the reacting chemicals contact the mold surfaces. |
| Split Bolster: This is a dual firmness or density bolster. The bolster is split by a narrow trench, which places firmer or higher density foam on the outer edge of the bolster and softer or lower density foam in the inner portion of the bolster. |
| Support Factor: The ratio of the 65% IFD to the 25% IFD reading. |
| Tear Resistance: A measure of the force required to initiate/continue a tear in foam. |
| Vapor Staining: The discoloration of a control vinyl sample from the volatiles released from foam. |
| Wet Aging: An accelerated aging method that requires the foam to be placed in an environmental chamber for a predetermined amount of time at elevated temperature and humidity levels. |
| 7.0 REFERENCES |
ASTM Standards: D624, D3574, D5132, D3453
ISO Standards: 34, 845, 2439, 3385, 3795
OEM Standards:
Federal Motor Vehicle Safety Standard: FMVSS 302 (CFR49 571.302)
SAE Standard: J1351, J1756 |
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| Appendix A - Supplemental Test Methods |
| Force Indentation Test Method (Bolster Hardness) |
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The b-surface of the pad underneath the test location must be fully supported by a load test fixture (reference section 3.4). The side of the bolster must also be supported for a split bolster pad. |
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Center the hemisphere above the test location designated on the part drawing. |
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A preload is applied to the sample, at a constant crosshead speed, and a reference point is determined. |
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From the reference point, indent the sample at a constant crosshead speed, until the deflection reaches the specified penetration depth |
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Dwell at the specified penetration depth for the designated time period and record the force in Newtons. |
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Typical Test Parameters
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Conventional Bolster
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Split Bolster
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Hemisphere Diameter, mm
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50
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20
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Preload, N
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1.25
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0.2
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Penetration Depth, mm
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12.7
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14
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Crosshead Speed, mm/minute
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38
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50
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Dwell, seconds
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5
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0
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| Part contour, thickness, and bolster type may dictate the use of a different size indentor or penetration depth to achieve repeatable readings. Test variations to this method are acceptable if agreed upon by the customer and supplier. Variations shall be designated on the engineering drawing. |
| Vapor Staining Test Method |
| Objective: To determine the potential for molded PUF to stain a selected grade of vinyl trim material. |
| Test Materials |
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Glass bottle, 2.0 L +/- 200 ml, with a metal screw foil-lined cap. The cap diameter shall be at minimum 60 mm.. |
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GM Vinyl Coated Fabric (Prado Grain), available from Test Fabrics1, cut into an 80 mm diameter disc or a circular size that fits tightly into the bottle cap. |
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Specimen cut from a molded part, 70 x 70 x 30 mm (+/- 2 mm on either dimension) with skin on the 70 x 70 mm face. |
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| Note 1: |
Test Fabrics, Inc., 415 Delaware Avenue, PO Box #26, West Pittison, PA 18643
Tel: 570-603-0432,
Fax: 570-603-0433,
E-mail: testfabric@aol.com |
| Test Equipment |
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Air-circulating oven capable of maintaining a temperature of 100 ± 2°C for 72 hours (temperature should be recorded or monitored). |
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Color spectrophotometer. |
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| Test Procedure |
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Check to ensure the glass bottles and lids are clean and free from contaminants. Prepare two bottles: a control bottle with no foam sample and a test bottle with foam. |
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Measure the color of the Vinyl samples using the spectrophotometer and record the original L* a* b* data. |
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Insert a Vinyl disc into the lid of each bottle with dress face outwards. |
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Place foam sample on the bottom of test bottle with skin side facing upwards (towards the lid). The control bottle will have no foam in it. |
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Carefully screw on the lids, ensuring the Vinyl discs remain in place, and hand tighten them. |
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Place the closed bottles in the oven and note temperature and time. |
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After 72 hours, remove the bottles from oven, open lids carefully, extract the PVC discs from lids and allow to cool to lab conditions, 23 ± 2°C, 50 ± 5% RH, for at least 1 hour. |
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Measure the final color of the vinyl samples and again record the L* a* b* data. |
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Using the original and final L* a* b* data, calculate the ΔE for both Vinyl samples (control and test) using the following formula: |
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Δ E =[Δ L² + Δ a ² + Δ b ²] ½ |
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To obtain the color change due to the foam, ΔE foam, subtract the ΔE of the control bottle PVC (ΔE control) from the ΔE of the test bottle PVC (ΔE test). |
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ΔE test - ΔE control = ΔE foam |
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| Note: Glass jars should be washed clean after each test, dried thoroughly, and stored with caps screwed in place to avoid ingress of any chemicals into the jars. |
| Record |
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ΔE of the control bottle and ΔE of the test bottle, ΔE control and ΔE test. |
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Color Change in Vinyl due to foam, ΔE foam |
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| Optionally, photos may be taken of the Vinyl discs before and after oven treatments for visual comparisons. |
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| Appendix B |
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Design Guidelines for the Use/Application of Polyurethane Foam in Automotive Seating
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| Introduction |
| A panel of industry experts selected the material properties that appear in this polyurethane seating specification. The properties and requirements were chosen because they are identified as key foam characteristics, which relate to the functional application of polyurethane foam in an automotive seat. It was also recognized that, while these properties characterize the foam, they do not address its application from a seat engineering perspective. These guidelines are provided to help fill that gap and to highlight some of the most common misconceptions about foam. |
| Temperature and Humidity Effects |
| The temperature and relative humidity level, in the atmosphere where the foam is conditioned prior to and during testing, affects the hardness of the foam. This is the reason that all foam labs are maintained at standard conditions of 23 + 20 C and 50 + 5% RH. Seating foams will soften as temperature or humidity rises and become harder as they decrease. An instrumented foam hardness tester can measure hardness changes at relatively small shifts in temperature or humidity. However any increase or decrease in hardness would have to be fairly significant for a person to feel the difference. Foam hardness change is related to the transient environmental condition in the test lab and it is not permanent. |
| Foam Hardness |
This specification uses Indentation Force Deflection (IFD), the current industry standard method, for measuring the hardness of foam blocks and seat pads. IFD is a repeatable and reliable test method for monitoring the hardness of foam from a quality standpoint, but it has its drawbacks as a design/engineering measurement. IFD measures foam hardness by indenting the test sample, with a 200 mm diameter compression plate, a specific percentage of its overall thickness, typically 50%. This means the IFD value is relative, because it is thickness dependent. To demonstrate this thickness effect, it is estimated that the 50% IFD value of a foam test block will decrease by approximately 12% for every 25 mm reduction in thickness. Pad geometry or components may also effect the IFD value.
Compression Force Deflection (CFD) on the other hand provides an absolute hardness measurement since the same size specimens, typically 50 x 50 x 25 mm, are cut from the interior or core of the foam block or part. This eliminates the influence of thickness, pad geometry and components. The hardness of a CFD specimen is measured very similarly to the IFD, except the compression plate is larger than the sample surface area. Unfortunately CFD also has its drawbacks. Since it is a destructive test and more time consuming than IFD testing, it is not suited for monitoring production process harnesses. It is only recommended as a design/engineering or benchmark test to compare the absolute hardness level of foam samples at dissimilar thickness. (See ASTM D3574, Test B1 and C for test method details) |
| Balancing Hardness and Density |
| Typically a seating pad will have a defined thickness based on the vehicle type and available interior space. Because of this, foam density and hardness become the remaining two variables, which is why the balance between these two properties is essential to achieve the desired level of performance from the part design. This specification segments polyurethane foam into four types and for each type there is a minimum core density requirement. It is important to understand that at the minimum density or at any other density foam can be produced over a fairly wide hardness range. If hardness is increased at a constant density the physical property values will become increasingly closer to the maximum allowable performance level for each foam type and eventually exceed the requirement limits. This is particularly true for the three properties that are associated with durability and comfort: Hysteresis Loss, Wet Set, and Constant Force Pounding. |
| Property Types |
| As noted in section 1.2 and 3.2 of this specification, the seat engineer needs to consider several factors concerning seat design, occupant expectations, vehicle type, and usage level when specifying the foam type for the pad under consideration. Depending on the design, vehicle class, and performance expectations, the same seating location in different vehicles, may not use the same foam type. This is also true for pad location within a vehicle. Higher demands will certainly be placed on a driver cushion than one located in the third row of an SUV, so the appropriate foam type selection is important for both performance and economical reasons. The table below gives a general guideline of how the foam types in this specification would be applied in an automotive vehicle. |
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Seat Location
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Foam Type
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I
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II
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III
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IV
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1st Row Cushion (Driver or Passenger)
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 |
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2nd Row Cushion (SUV & Sedan)
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1st Row Back
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 |
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2nd Row Back (SUV & Sedan)
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3rd Row Cushion
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3rd Row Back
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| General Best Practices |
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Design the seat system to ensure that the foam is in Compression. |
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Support the pad properly to minimize bridging gaps and to prevent putting the foam in tension. Polyurethane foam cushion is not a structural component. |
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Foam pads should be designed at a realistic foam thickness to avoid over compression of the foam. |
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If foam pad thickness is decreased, the density of the pad should be proportionately increased. In general, this will maintain the pad performance level, because the polymer content of the pad will remain the same. |
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A gap should not exist between the B-surface of the foam pad and the seat pan or suspension. |
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Coring is allowed in non-load bearing areas, and it should be reviewed on a design basis. |
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Avoid foam overhang around the structural seat pan b-surface foam bolster support. An unsupported bolster causes the foam to hinge, in tension, instead of compressing during occupant ingress/egress. ndle |
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Ensure there are no sharp edges (metal) adjacent to a foam surface. |
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When using suspensions, a treatment (such as cloth) on the B-side of the foam, is recommended to distribute point loading and avoid penetration of suspension into foam. |
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Ensure the package space is realistic in relation to foam thickness and specified H-Point. This will avoid over or under compression of the foam cushion. |
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| Recommended Technical Papers |
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G.R. Blair and A.R. Wilson, Polyurethane Automotive Cushioning: In Car Durability vs Foam Properties, 35th Annual Polyurethane Technical/Marketing Conference Oct. 9-12 1994, Boston, MA pp. 478 - 488 |
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G.R. Blair and A.R. Wilson, Polyurethane Automotive Cushioning: Material Properties After In-Car and Simulated Durability Testing, 36th Annual Polyurethane Technical/Marketing Conference Sept 26 - 29 1995, Chicago IL, pp. 413 - 417 |
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G.R. Blair and R.J. Horn, Fleet Durability Testing of Molded Polyurethane Foam and Competitive Automotive Cushions, Utech 96, March 26-28 1996, paper 5 |
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G.R. Blair, R.J. Bailey, I. Rai, and M. Weierstall, Resistance/Recovery of HR Foam Seating to Climatic Changes and Media Attack, Polyurethanes Expo, October 13-16, 2002 |
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A. Ali, G.R. Blair, J. McEvoy, and M. Weierstall, Hardness Test Methods Comparison and Correlation to H-Point Measurements, API Conference, Sept 25-27 2006, Salt Lake City Ut, pp 526 - 542 |
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R. Brasington and H. De Roeck, Accelerated Testing for Durability Performance of Automotive Seating Foam, Polyurethanes Conference 2000, October 8-11 2000, Boston, MA, pp 270-279 |
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B.L. Neal, Differences in Dynamic Performance of Molded Polyurethane Foam as a Function of Pad Thickness and Supported Load, Polyurethanes Conference 2000, October 8-11 2000, Boston, MA, pp 365-373 |
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M.A.Koshute, M. Blaszkiewicz, and B Neal, Benchmarking of Polyurethane Technologies for Automotive Seat Cushions, Polyurethanes Expo 2001, September 30 - October 3, 2001, Columbus, OH, pp 247-254 |
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A. LeFever and J. McEvoy, Alternative Methods for Durability Specification, Polyurethanes Expo 2002, September 30 - October 3, 2001, Columbus, OH, pp275-279 |
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J. McEvoy and R. Yamasaki, Accelerated Aging and Durability Testing of Polyurethane Foams, Polyurethanes Expo 2001, September 30 - October 3, 2001, Columbus, OH, pp 281-284 |
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J. McEvoy and R. Yamasaki, Regional Accelerated Aging Test, Polyurethanes Expo 2002, October 13-16, 2002, Orlando, FL, pp 335-343 |
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J. McEvoy, T. McRoberts, R. Yamasaki, Test of Dynamic Properties in Different Environmental Conditions with Different Occupant Weight, Polyurethanes Expo 2003, October 1-3, 2003, Arlington, VA, pp 205-215 |
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G.R. Blair, A. Russ, D.E. Bradt, and R.J. Bailey, Measurement of High Resiliency Molded Foam Properties as a Function of Climatic Conditions, Polyurethanes Expo 2001, September 30 - October 3, 2001, Columbus, OH, pp 285-309 |
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B. Neal, G.R. Blair, J. McEvoy, R. Pask, and M. Weierstall, Molded Polyurethane Foam Durability Testing as a Response to Applied Work, CPI Conference, September 24-26, 2007, Orlando, FL |
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B. Dawe, G.R. Blair, J. McEvoy, R. Pask, M. Rusan, and C. Wright, The Effect of Visible Light on the Variability of Flexible Foam Compression Sets, CPI Conference, September 24-26, 2007, Orlando, FL |
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K. Saotoma, K. Matsurbara, and T. Yatomi, The Improvement of Humidity Resistance in High Resilient Polyurethane Foam, Journal of Cellular Plastics, May/June 1997 |
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R. Volland and H.M. Rothermel, Advantages of a New HR-Molding Technology, SAE International Congress & Exposition, February 28 - March 4, 1983, Detroit, MI, 830486 |
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G.R. Blair, A. Milivojevich, J.G. Pageau, and Jeff Van Heumen, Automotive Seating Comfort; Defining Comfort Properties in Polyurethane Foam, SAE International Congress & Exposition, March 1-4, 1999, Detroit, MI, 1999-01-0587 |
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