Superior Processing New all-mdi Solutions for Automotive Seating with Low emission of Volatile Organic Compounds (VOC)

Transcription

1 Superior Processing New all-mdi Solutions for Automotive Seating with Low emission of Volatile Organic Compounds (VOC) SABRINA FREGNI Dow Formulated Systems Dow Italia srl ALAIN FANGET Automotive Systems Dow Europe GmbH Abstract: Cabin air quality is a growing concern raised by various automakers throughout the world. Specifications are becoming more and more stringent and the leading specifications are being adopted by more OEMs. The emphasis on Volatile Organic Compounds (VOC) emission has been broadened and the target of reducing overall VOC emissions from materials within the cabin of the car is now combined with the control of specific organic compounds, which are not anymore accepted, even if their contribution to the total emission is very limited. The Dow Chemical Company has recently made significant advances in the design of a new generation of cost effective, high resilience all-mdi based solutions that enable to fulfill the new most severe VOC emission requirements, while maintaining good foam physical mechanical properties, outstanding durability and properties retention after heat and humid aging. When automotive seating is the end use, the main advantages of this new systems generation is the superior processing characteristics that reflect into the excellent aesthetic of the resulting piece, even with very complicate mold shapes and in combination with dual-hardness multi pouring technology. This new generation of products offers a high degree of design flexibility combined with a wide load bearing and hardness range. The new Dow technology uses a very specific selection of raw materials in combination with MDI based prepolymers, where the MDI isomer/oligomer ratio has been thoroughly examined and optimized to fit different physical mechanical properties requirements. The use of only reactive types of components and the control of byproducts and raw materials impurities allows Dow to fulfill the most severe VOC specifications requirements. This paper will present case studies of polyurethane molded foams for seating capable of matching very challenging specifications requirements at different applied densities. Data analyzed in the paper have been obtained not only using specific laboratory methods and tools that allow understanding and predicting foam processing under specific production conditions, but mainly using actual parts taken from molders production plants, where these systems are already commercialized. Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow

2 Introduction: In early 2000, a lot of publications focused on the presence of Volatile Organic Compounds (VOCs) in the interior of a vehicle. The plastic materials were viewed as the culprits for the VOCs emission in the vehicle cabin. Since approximately 13 Kg of polyurethane foams are utilized in a car ranging in applications from seat cushions to head rests, instrument panel foams and headliners, these materials were examined as potential causes of the VOCs emissions. This report focuses on the polyurethane foam as a source of VOC and subsequent routes available to curb this issue as it pertains to these materials. In the recent years, we have seen an increase in the desire to reduce odor and VOC in the interior of the vehicle. This is the growing trend for the OEM s in Europe, where the limit for total VOC emission in the OEM s specifications is often combined with a list of components that are not accepted, even if their contribution to the total emission is minimal. In addition to the concern over VOCs present in the cockpit of automobiles, building and construction guidelines in Japan are being applied to the interior of cars 1. The regulations from the Japan Automotive Manufacture Association, JAMA are being applied for complete interior cabin vehicle testing. These regulations are not looking at just the concentration of volatile organic compounds but are focusing on the concentration of specific organic compounds. Besides having a variety of material applications and targeted concentrations, the matter is further complicated by having a variety of test methods. All of the methods use an accelerated heat aging of the sample in order to understand the potential exposure overtime and very sensitive chamber tests have been recently implemented by various OEM s. One of the primary sources of VOCs in polyurethane foam is related to the fugitive tertiary amine catalysts. The low molecular weight amine catalysts provide excellent mobility and sustain high catalytic activity during the entire reaction, but these catalysts are not incorporated into the polymer so they can easily migrate and evaporate from the foam over time. The migratory catalysts contribute to odors in the car cabin, fogging of the window screen in the automobile, as well as staining of PVC instrument panel skins, and the degradation of polycarbonate articles. In this respect, only reactive or non-fugitive type of catalyst and additives has to be taken into consideration when developing low VOC emission flexible polyurethane foam. The catalyst suppliers have responded by introducing a variety of new, non-fugitive (sometimes called reactive) amine catalyst compositions. Examples of their success at reducing emissions while providing catalytic activity are recorded in the literature, nevertheless difficulties associated with reactivity profile adjustment, higher usage levels and losses in certain foam physical properties suggest that an improved level of technology is needed. This challenge has been overcome by Dow trough the development of a new series of polyols with built in catalytic activity. This technology is described in detail in US patent # US B2 titled Polyols with Autocatalytic Characteristics and Polyurethane Products Made Therefrom 7 and it allows a significant reduction of the catalyst package necessary to produce foams under given conditions, therefore reducing the amount of VOC s emitted from the foam, without compromising foam physical mechanical properties and properties retention after humid aging. It has to be underlined that, while amine catalysts are one of the major source of VOCs in polyurethane foam, all the impurities eventually present in the raw materials and the antioxidants (AO) used in the base polyol significantly contribute to the total emission of the polyurethane foam. The development of low VOC types of polyurethane foams needs therefore the selection of raw polyol and isocyanate components specifically designed to control and minimize the presence of not accepted by-products. The request to reduce VOC emission from interior car components is recently combined with the typical need of the automotive industry that can be summarized as excellent foam processing, allowing for production of very complicated parts with automated carousel, good physical mechanical properties, durability behavior and aging resistance even at lower applied densities. The right balance between the need to improve the car seats' performances in terms of safety, comfort and design and a very strong requirement for cost reduction is also required. The reduction in applied density caused by the

3 need to reduce costs is in line with the tendency towards the overall weight reduction of car interiors, while the recent development in car seats' design, have led to the requirement for even lower density polyurethane foams capable of maintaining unaltered or even improving durability and foam processing, providing extreme design flexibility. The efforts to improve the overall properties of the seats can be achieved by optimizing the weight of the foam used in the production of car seating and its properties and by satisfying specific requirements in terms of density and durability for the different parts of the car, such as front and rear cushions, backrests, headrest and armrest. The objectives of the development activities for molding technology are even more challenging, due to the fact that a combination of different OEM s specifications requirements must be fulfilled by a single system as foam producers are willing to use a single system in a carousel to produce various parts for various car models. Especially in the European market, the widespread use of all-mdi based technology is noticed and it can be attributed to the increase in productivity determined by short cycle times and fast curing. The good results obtained with dual or multiple hardness technology, as well as the wide range of foam hardness that can be achieved through variation in the NCO-OH index further contribute to positively influence the penetration of all- MDI based technology particularly in the production of front seats, where high hardness and high durability are generally required. As previously described in the Paper Low Volatile Organic Compounds Solutions for Flexible PU Foam The Dow Chemical Company as embarked on an effort to develop the next generation of all-mdi based systems for flexible polyurethane foam, able to fulfill the recent requirements of low VOC emissions, combined with good foam durability properties and property retention after heat and humid aging. The technology is available and already commercialized under the SPECFLEX TM designation. This paper reports on the continued efforts by The Dow Chemical Company to expand the offering of this new SPECFLEX TM systems, in order to satisfy specific request in terms of foam processing, production cycles time and final foam density without penalties of VOC emission, foam durability and property retention after aging. In spite of many and well known general MDI advantages, the most relevant MDI limitations and issues are related to a limited foam flow-ability and the relative difficulties in reaching low foam densities combined with high foam processing and aesthetic. The paper will present the results of our most recent development work that has led to significant density reduction (below 40 kg/m 3 ) without compromising foam processing and VOC emission. This technology is a valid solution to be applied to fulfill the requirements of backrests and rear seat, where low applied densities are accepted. Three components systems (one isocyanate and two polyols) have been designed for dual hardness technology with a particularly wide range of hardness and density. Very fast foam curing and very open foam, combined with extremely good flow-ability is also analyzed. This all- MDI based technology has been specifically developed for production of very complicated seat design, where fast production cycle time is required and foam crushing operation may result difficult. To conclude, very low applied density, combined with extremely fast curing (45 sec) polyurethane foam systems will be presented. This technology is available and regularly commercialized for production of headrest and small parts by the foam in fabric technology. INDUSTRY REQUIREMENTS The typical requirements for polyurethane materials used in automotive car interiors is the balance between processing, to give acceptable first pass prime parts and the physical / mechanical properties. The overlapping area is the balance between excellent foam processing allowing for production of very complicated parts using an automated carousel, extremely low scraps rate, good physical/ mechanical properties, durability behavior and aging resistance even at lower applied densities. Very fast production cycles times that require fast foam curing, combined with low applied density without penalties of the car seats' performances in terms of safety, comfort and design is also request to reduce cost. The new criteria of acceptable VOC emissions bring a new dimension which needs to be balanced with the rest stated above, which restricts the optimum performance to a narrow overlapping area.

4 The specification for polyurethane foam is complex and the matter is further complicated since each OEM has particular requirements and test methodologies. To control the emission of Volatile Organic Components each of the OEMs has particular test methodologies and specifications requirements. The requirements have changed from overall VOC and FOG to a focus on particular organic compounds. All of the methods use an accelerated heat aging of the sample in order to understand the potential exposure overtime. Table 1 shows a compilation of the various methods used in the industry to characterize materials with some of the detail on temperature, exposure conditions and sample size. A summary of the typical European OEM specifications requirements is reported in table 2. Table 1: VOC and FOG test method Method Temperature setting Exposure conditions Sample size Odor VDA , 80, 60 C const 2 h equilibrium mg Fogging DIN A Reflectometric 100 C const 3 h equilibrium mg Fogging DIN B Gravimetric 100 C const 16 h equilibrium mg Headspace emission VDA C const 5 h equilibrium 3000 mg Thermo-desorption VOC VDA C const 30 min He flow 30 mg Thermo-desorption FOG VDA C const 90 min after VOC 30 mg CARB test VDA 276, GS cycles 24 h equilibrium Total part Table 2: Main European Foam emission Specifications requirements Test method Specifications Requirements Odor VDA Amine catalyst Emission No Visual Color change from VW standard PVC-Foil and No Specific (PVC staining test) amine odor PV 3925 Formaldehyde 10 mg/kg DIN Method B Fogging 1 mg Headspace emission VDA 277/PV µgc/g Thermo-desorption VOC VDA 278 VOC 100 µg/g Thermo-desorption FOG VDA 278 FOG 250 µg/g Critical individual substances shall not exceed the limit/target values indicated in test specifications PB VWL 709, Annex 6 GS SHED Chamber GS SHED Chamber + Determination of BTXES and N- nitrosoamines HC-Total according to CARB 1.0 mg/kg General applies: the emission requirements are in the apron with the specialist department co-ordinate with respect to analysis extent. The components may not contain forbidden substances according to GS Part 1-4. The specifications for foam physical mechanical properties, foam durability and aging resistance are as varied as those for emission testing. Very severe heat and humid aging tests are requested by the European OEM, but each of them prescribes different test methodology and conditioning requirements for the aging. A summary of the main tests method applied in Europe for foam physical mechanical properties, durability and property retention after aging are reported in table 3.

5 Table 3: main tests method applied in Europe for foam physical mechanical properties, durability and property retention after aging Specifications Conditions As received conditions DIN EN ISO 1856 (50% compression) Compression Set D (70% compression) After Heat aging DIN EN ISO 1856/DIN EN ISO 2240 (7 days at 140 C) DIN EN ISO 1856 After + 90 C circulating air for 200 H After Humid aging DIN EN ISO 1856 after + 90 C (100-6% RH ) 200 h DIN EN ISO 1856/DIN EN ISO 224 (5h at 120 C, 3 cycles) As received conditions DIN EN ISO Compression hardness Compression hardness variation after heat aging DIN EN ISO /DIN EN ISO 2240 (7 days at 140 C) DIN EN ISO After + 90 C circulating air for 200 H Compression hardness variation after humid aging DIN EN ISO After moist heat aging : + 90 C (100-6% RH ) 200 H DIN EN ISO /DIN EN ISO 2240 (5h at 120 C, 3 cycles) Dynamic fatigue test Tensile Strength and Elongation at break Tear propagation strength As received conditions D DIN /50-1 Tropical conditions DIN /92-1 As received conditions DIN EN ISO 1798 After heat aging DIN EN ISO 1798 after + 90 C circulating air for 200 H DIN EN ISO 1798 /DIN EN ISO 2240 (7 days at 140 C) After Humid aging DIN EN ISO 1798 After moist heat aging : + 90 C (100-6% RH ) 200 H DIN EN ISO1798 /DIN EN ISO 2240 (5h at 120 C, 3 cycles) As received conditions DIN TECHNICAL SOLUTIONS The Dow s approach is based on the development of customized solution to fulfill the specific customer requirements. Our approach was to develop laboratory tools and procedures to predict and quantify typical foam processing limitations at the customers plant, such as foam finishing, foam flow ability and sensitivity and distributions of foam voids and collapses. The tools, procedures and methodologies developed are the results of systematic efforts in comparing laboratory activities to actual customer processing conditions. The formulations technology is based on the use of all-mdi based prepolymer, that are differentiated to fulfill the processing requirements of the different applications. The ratio between isomers and oligomers is optimized, while the OH terminated components part has been thoroughly examined and fine tuned especially for what it concerns its influence on cell opening performance. Several prepolymers have been developed, to be used in combinations with different formulated polyol, to differentiate the technology in terms of final foam curing, foam hardness, applied density and foam physical mechanical properties, without compromise of VOC emissions Formulated polyol is also designed to provide differentiated solutions. The formulation technology is based on the use of VORANOL VORACTIV polyols, which are able to catalyze the reaction of water and polyol with isocyanate through a grafted catalytic functionality. The use of high molecular weight, high reactivity and low unsaturation polyols in combinations with VORANOL

6 VORACTIV allows us to significantly reduce the use of reactive types of catalyst, in order to minimize their negative effect on property retentions after humid aging. Only reactive types of catalyst have been analyzed and optimized, in order to have the catalytic component incorporated into the polymer. 1. AUTOMOTIVE SEATING The automotive seating systems have been developed to enable good foam processing in thin seat designed combined with dual hardness multi pouring technology. Wide range of achievable molded density represents a differentiation opportunity to satisfy specific requirements in terms of density and durability for the different parts of the car, such as front and rear cushions and backrests. Three different case studies are presented. These fully formulated systems for production of polyurethane molded foams characterized by low VOC emission are commercialized under the SPECFLEX TM trade name. They are all-mdi based, specifically designed for automotive seating and capable of reaching different OEM s specifications requirements at a wide range of applied densities and final foam hardness. Very specific foam processing conditions are taken into considerations during the development activities. 1A. All-MDI very low applied density Table N 4 reports the results of Dow last development activities that led to further density reduction (in the range of 40 kg/m 3 ) without compromising foam processing and foam physical mechanical properties which still meet the OEM s specifications requirements for backrest and rear parts, where low applied density can be applied. Table N 4 summarized customer average data of front cushions and backrest belonging to actual production. The molding conditions were the typical one s for this process technology. Foams have been produced using High Pressure foaming. The molds, all made by aluminum and provided with water recirculation heating, belonged to the current car seats models. The typical mold temperature range was between 45 to 53 C. All the evaluated parts have been produced at the requested final foam hardness; some of them have been produced using dual-hardness multi pouring technology. They correspond to the new developed system RUN 438 experimental Polyol & Specflex NE 150 isocyanate processed at the typical density required for each parts. Actual core density ranges from 40 to 55 kg/m 3. It is interesting to underline that even the piece that was found with the lowest applied density, that was in the range of 40 kg/m 3, was able to fulfill most of the OEM s specifications requirements applied for backrest and rear parts. Moreover in spite of the very low applied density, the parts are still able to match some of the foam durability OEM s specifications requirement, that s typical of the front cushions generally molded at density higher than 50 kg/m 3. Table N 4: RUN 438 Polyol & Specflex NE 150 Isocyanate Foam parts produced in real production conditions Front cushion type of mold Front cushion type of mold Front backrest type of mold Rear cushion type of mold ISO/POL Rear cushion type of mold Dual hardness 0.67 /0.72 Core density ASTM D 3574 (Kg/m 3 ) Ball Rebound ASTM D 3574 % Fogging DIN B mg Gravimetric Tensile ID Pa strength Elongation at break D %

7 Tear strength D N/cm Compression set Wet Compression set CFD Dynamic fatigue tests D % ISO 1856 method A % % compression, 22h, 50 C, % % RH ISO KPa CFD variation after humid aging (1) D % Loss of Height after fatigue: DH % Loss of compressibility after fatigue: DP % (1) ISO 2440/ASTM D 3574 Test J, 5h 120 C Table N 5: RUN 438 Polyol & Specflex NE 150 Isocyanate Volatile Organic Components emission ISO/POL 0.63 Core density (Kg/m 3 ) 45 Total VOC emission VDA 277 mg C/ g 11.6 FOG VDA 278 µg/g 85 VOC VDA 278 µg/g 160 Odor tests VDA C/ 24h 1.5 VDA C/24h 3.0 VDA C/2h 3.0 1B. All-MDI, three components system designed for very good foam durability properties and wide range of hardness. It is well known that all-mdi based chemistry provide advantages in dual or multiple hardness technology because of the wide range of foam hardness that can be achieved through variation in the NCO-OH index. In some cases, when an extremely high difference between the soft and the hard segments of dual hardness parts in required, the wide load bearing latitude offered by an all-mdi system might not be enough. A three components system has been therefore developed to fulfill the specific request of wide hardness range applied for specific cushion and backrest models. This solution also allows optimizing density for each single part, when front cushions and rear parts are produced in the same production line. Table N 6 summarized customer average data of front cushions, backrest and rear parts belonging to actual production. All the evaluated parts have been produced at the requested final foam hardness, by the application of dual-hardness multi pouring technology and correspond to the new developed system RUN 330 and RUN 334 Experimental Polyols used in combinations with Specflex NE 150 isocyanate. The RUN 330 polyol is utilized to produce the soft area of front cushions and backrest, while RUN 334 polyol is used for the hard corner of the dual hardness parts. As you can see, the applied density ranges from 60 kg/m 3 required for the front cushion, to 45 g/l for the rear parts while foam hardness measured by the CLD 40% ranges from 5 KPa in the soft, to Kpa in the harder corner. The molding conditions were the typical one s for this process technology. Foam have been produced using High Pressure Three components foaming machine; the molds, all made by aluminum and provided with water recirculation heating, belonged to the current car seats models. The typical mold temperature range is between 45 to 53 C while final foam curing is fast enough to allow 4 minutes demolding time.

8 Foam physical mechanical properties have been tested according to test method typically applied for German OEM s specifications requirements. As reported in table N 6, foam durability properties and properties retention after aging measured on molded parts produced in real production conditions can fulfill typical European OEM s specifications requirements for automotive seating, with no compromise of the Volatile Organic Components emissions, wich are reported in table N 7.

9 Table N 6: RUN 330 and RUN 334 POL used in combination with Specflex NE 150 Isocyanate All-MDI, three components system designed for very good foam durability properties and wide range of hardness. Foam parts produced in real production conditions ISO/POL Front Cushion Seat RUN 330/NE 150 Central soft RUN 334/NE 150 Corner Hard 0.50 Central soft 0.64 Hard corner Front Cushion Backrest RUN 330/NE 150 Central soft RUN 334/NE 150 Corner Hard 0.50 Central soft 0.60 Hard corner Rear Cushion 40% RUN 330/NE 150 Central Soft RUN 334/NE 150 Corner Hard 0.58 Central soft 0.68 Hard corner Rear Backrest 60% RUN 330 /NE Core density Ball Rebound Fogging condensate Tensile strength Elongation at break Tear strength Compressio n set ASTM D 3574 (Kg/m3) 64 (Central soft) 63 (Corner hard) 61 (central soft) 61 (Corner hard) 48 (Central soft) 47 (Corner hard) ASTM D 3574 % DIN 75201B mg ISO 1798 (1) KPa ISO 1798 (1) After heat aging (2) KPa ISO 1798 (1) KPa After humid aging (3) ISO 1798 (1) % ISO 1798 (1) After heat aging (2) % ISO 1798 (1) % After humid aging (3) ldin (6) N/cm ISO 1856 (4) % ISO 1856 (5) % CFD ISO 1856 % After humid aging (3) ISO KPa 5.3 Soft 13.0 Hard 5.0 Soft 11.8 Hard 6.4 Soft 11.0 Hard 6.9 CFD Iso KPa 4.2 (Central soft) 4.3 (Central soft) 4.9 (Central soft) 5.2 after humid aging (3) (1) Tensile specimen A, Traverse speed 100mm/min (2) Heat aging: + 90 C/circulating air for 200 h (3) Humid aging: +90 C/(100-6)% RH for 200 h (4) 5x5x2.5 cm, NO skin, 50% deformation, 22h, 70 C (5) 5x5x2.5 cm, NO skin, 75% deformation, 22h, 70 C (6) Long leg specimen 100x30x10mm, length of the cut 40mm

10 Table N 7: RUN 330 and RUN 334 POL used in combination with Specflex NE 150 Isocyanate Volatile Organic Components emission Front Cushion Seat RUN 330/NE 150 Central soft RUN 334/NE 150 Corner Hard ISO/POL Total VOC emission VDA 277 mg C/ g Formaldehyde Emission PV 3925 mg/g 1.1 (1) 2.1 (1) Odor tests VDA C/ 24h VDA C/24h VDA C/2h (1) Average of 5 tests C- all-mdi medium to high applied density, very fast curing The need of the automotive industry to improve the car seats' performances in terms of safety, comfort and design have led to the requirement for polyurethane foams capable of maintaining unaltered or even improving durability and foam processing, providing extreme design flexibility. In few cases the reduced applied density is not applicable as an opportunity for cost reductions, while advantages in terms of foam processing, such as extremely fast foam curing, allowing for easy and fast production cycle time even in combination with extremely complicate mold shape is the real advantage. Table N 8 summarized customer average data of front cushions and backrest produced using the recently developed system RUN 408 Polyol used in combination with PFL 9010 Isocyanate. All the evaluated parts have been produced in real production conditions, at applied densities ranging from 60 to 75 kg/m 3, as for the requirement of the final application. Foam have been produced using High Pressure mixing; the molds are made by aluminum, provided with water recirculation heating to have temperature in the range of 60 C. Final foam curing is very fast to allow demolding time not longer than 3 minutes and very easy crushing operation in spite the very thin and complicate mold design, particularly evident in the backrest model. The expectation for such high quality of foam, is to fulfill the most severe requirements for low VOC emission, with no compromise of foam physical mechanical properties, foam durability and foam properties retention after severe heat and humid aging. Foam physical mechanical properties are reported in table N 8, while the Volatile Organic Components Emission results are reported in table N 9. The tests have been performed according to some of the most severe test methods typically applied from the German OEM s for high quality and high density types of foam.

11 Table N 8: RUN 408 Polyol and PFL 9010 Isocyanate kg/m 3 density Foam parts produced in real production conditions Front Cushion Seat Front Cushion Seat Front cushion seat Front backrest seat ISO/POL Core density ASTM D 3574 (Kg/m 3 ) Ball Rebound ASTM D 3574 % Fogging DIN 75201B mg Tensile ISO 1798 (1) N/mm strength ISO 1798 (1) After N/mm heat aging (2) ISO 1798 (1) N/mm After moist heat aging (3) Elongation at ISO 1798 (1) % break ISO 1798 After % heat aging (2) ISO 1798 (1) % After moist heat aging (3) Tear strength DIN (4) N/cm Compression ISO 1856 (5) % set ISO 1856 (8) % ISO 1856 (5) After Humid aging (3) % ISO 1856 (5) % After Humid aging (7) CFD ISO KPa CFD Iso After Humid aging (3) KPa CFD Iso After Humid aging (7) KPa (1) Tensile specimen A, Traverse speed 100mm/min (2) Heat aging: + 90 C/circulating air for 200 h (3) Humid aging: +90 C/(100-6)% RH for 200 h (4) Long leg specimen 100x30x10mm, length of the cut 40mm (5) 5x5x2.5 cm, NO skin, 50% deformation, 22h, 70 C (6) 7 days, 140 C (7) 5h, 120 C, 3 cycles (8) 5x5x2.5 cm, NO skin, 75% deformation, 22h, 70 C Table N 9: RUN 408 Polyol and PFL 9010 Isocyanate kg/m 3 density Volatile Organic Components emission ISO/POL ratio 0.58 Core density (Kg/m 3 ) 62 Total VOC emission VDA 277 mg C/ g 13.2 FOG VDA 278 µg/g 88 VOC VDA 278 µg/g 190 Odor tests VDA C/ 24h 2.0 VDA C/24h 3.0 VDA C/2h 3.0

12 2. Headrest by Foam in Fabric technology As described in the Paper Low Volatile Organic Compounds Solutions for Flexible PU Foam The Dow Chemical Company as embarked on an effort to develop new generation of all-mdi based systems for flexible polyurethane foam, to be used for production of small parts such as armrest and headrest. The systems mentioned in the paper are available and commercialized under the Specflex TM trade name; they have been designed for production of headrest and armrest characterized by applied density ranging from 50 to 75 kg/m 3 and able to fulfill the new request of the automotive industry in terms of low VOC emission. The paper Low Volatile Organic Compounds Solutions for Flexible PU Foam reports the details of foam physical mechanical properties, durability, properties retention after aging and volatile organic components emission measured on foam samples produced using this new low emission, all-mdi based system family. It is worth mentioning that the possibility to fine tune the formulation inherent in this approach gave us the opportunity to differentiate our response to better meet the specific requirements of the market, with the development of other systems within this new generation of products that are currently commercialized. A technology largely applied in the market as alternative to the more traditional molding technology is the so called Foam in Situ technology. The peculiarity of Foam in Fabric or Foam in Situ technology is that foam is poured directly into the fabric, which has been prepared specifically for this use. Many advantages are offered by this technology: the part is produced in one step only and right after demolding it is ready to be installed in the car, the production cycle time is very fast, no release agents and no mold heating are required. These advantages result in a lower cost of production. The main critical issues to be considered when this technology is applied for production of headrest is the outlook of the final parts, that has to be excellent, thus the flexible polyurethane foam must not pass through fabric and sewing. The solutions that need to be applied to avoid scraps come from both the production technology and the specific system design of the polyurethane flexible foam. The fabric is normally combined with laminated foam with the proper cell structure to avoid any kind of interaction while reactivity and rising profile of the flexible foam system play an important role to avoid fabric and sewing overflow. An additional peculiarity of this specific application is that the parts are not crushed after demolding, therefore the flexible molded foam has to be very open, to avoid shrinking. It is worth mentioning that while specifications requirements for foam physical mechanical properties and aging resistance can be less demanding when headrests are produced by Foam in Situ Technology, no compromise are accepted for the Emission of Volatile Organic Components, in which the most severe requirements recently introduced for seating applications are applied. Two all-mdi based systems have been recently developed for production of Headrest by foam in fabric technology. The systems are already regularly commercialized under SPECFLEX TM trade name and they have been specifically designed to fulfill the recent low VOC emissions requirements of the automotive industry. Foam physical mechanical properties and VOC emission measured on foams parts produced using this new SPECFLEX TM system family are described in table N 10 and 11. Two different solutions are presented: MFA 9270 Experimental polyol, used in combinations with Specflex NE 134 isocyanate, specifically designed for low emission type of foam having average core density ranging from 50 to 60 kg/m 3 density. Specflex NF 916 Polyol, used in combination with Specflex NE 371 isocyanate, specifically designed for very low applied density (in the range of 40 kg/m 3 ) combined with very fast foam curing, that allows production cycle time in the range of 45 sec. Tables N 10 and 11 summarize customer average results of headrests belonging to actual production. The molding conditions were typical for this process technology. Foams have been produced using High Pressure foaming, the molds are not heated and they are made by aluminum.

13 All the evaluated parts are not crushed after demolding and they have been produced at the requested final foam hardness. Demolding time was 90 sec for parts produced using the MFA 9270 Polyol & Specflex NE 134 Isocyanate system, while all the samples produced using the Specflex 916 Polyol used in combination with Specflex NE 371 isocyanate have been demolded in 45 sec. As clearly demonstrated, in spite the fast foam curing, allowing for fast production cycle time, and the low applied density, the foam can still fulfill some of the German OEM s specifications requirements for VOC emission. Table N 10: Specflex NF 916 Polyol & Specflex NE 371 Isocyanate Headrest, Foam in Fabric technology Method Unit Results Demolding time sec 45 ISO/POL 0.62 Core density Kg/m 3 39 Tear Strength DIN N/mm 0.25 Tensile strength Elongation at break Compression Set DIN/EN/ISO 1798 KPa 135 DIN/EN/ISO h at 120 C, 3 Cycles KPa 95 DIN/EN/ISO days at 140 C KPa 90 DIN/EN/ISO 1798 % 83 DIN/EN/ISO h at 120 C, 3 Cycles % 72 DIN/EN/ISO days at 140 C % 79 DIN/EN/ISO %at 70 C 50% compression % 10 DIN/EN/ISO %at 70 C 50% compression DIN/EN/ISO h at 120 C, 3 Cycles DIN/EN/ISO %at 70 C 50% compression DIN/EN/ISO days at 140 C % 20 % 11 CLD 40% DIN/EN/ISO 3386 KPa 9.8 Volatile Organic Components emission Fogging DIN B mg 0.35 VOC VDA 278 µg/g 81 FOG VDA 278 µg/g 202

14 Table N 11: MFA 9270 Polyol & Specflex NE 134 Isocyanate Headrest, Foam in Fabric technology MFA 9270 Polyol & Specflex NE 134 Testing condition Unit Isocyanate Demolding time sec ISO/POL Core density Kg/m Amine catalyst emission PV pass pass pass Formaldehyde emission PV (6) Fogging DIN B 0.65 Organic Compounds VDA 270 µgc/g) 41 Compression Set Tensile strength Elongation at break Tear propagation strength ISO 1856 (1) % ISO 1856 after Humid aging (2) % ISO 1798 (3) N/cm ISO 1798 (3) after heat aging (4) N/cm ISO 1798 (3) after humid aging (2) N/cm ISO 1798 (3) % ISO 1798 after heat aging (4) % ISO 1798 after humid aging (2) % DIN (5) N/cm (1) 5x5x2.5 cm, NO skin, 50% deformation, 22h, 70 C (2) Humid aging: +90 C/(100-6)% RH for 200 h (3) Tensile specimen A, Traverse speed 100mm/min (4) Heat aging: + 90 C/circulating air for 200 h (5) Long leg specimen 100x30x10mm, length of the cut 40mm (6) Average of 5 tests

15 Conclusions: The Dow Chemical Company has developed industry-leading solutions to the issue of volatile organic compounds in the interior of the vehicle. The experience and understanding of chemistry and material science and the use of the autocatalytic polyol VORANOL VORACTIV are the keys to differentiate our offering in order to meet the demanding specifications of the OEM s and our customers physical property and processing requirements. The results of the efforts put by The Dow Chemical Company to expand the offering of these new SPECFLEX TM systems has been presented in the paper. The most relevant MDI limitation related to the limited foam flow-ability and the relative difficulties in reaching low foam densities has been overcome by the development of a low applied density (in the range of 40 Kg/m 3 ) system able to fulfill the new low VOC requirements, with no compromise of foam physical mechanical properties and foam processing, resulting in excellent aesthetic of the final part. In addition, customized solutions for automotive seating specifically designed for wide hardness range and very fast production cycles time at different applied densities and in combination with very complicate seat design have also been described. The possibility to fine tune the formulation inherent in this approach gave us the opportunity to further differentiate our response by the development of low density and fast curing polyurethane foam suitable for production of headrest by foam in fabric technology.

16 Reference 1. JAMA Announces Voluntary Guidelines for Reducing Vehicle Cabin VOC Concentration Levels ~ To Satisfy Government Demands for 13 Volatile Organic Compounds ~ February 14, Burks, S., Kiszka, K., Thomas, C.D., Tenbrock, W., Development of Low-Emission Polyurethane Foam Formulations for Automotive Instrument Panel and Interior Trim Applications, UTECH 2007, Orlando, Florida 3. S. Fregni, A. Fangareggi, G Casagrande, A. James Low Volatile Organic Compounds Solutions for Flexible PU Foams 4. Casati, F.M., Fanget A, Godoy, J, Sonney, J.M., Prange, R, Influence of Non-Fugitive Catalysis on Physical Characteristics of Automotive Polyurethane Molded Foam, Proceedings of the Polyurethanes Conference Casati, F.M., Fanget A, Godoy, J, Sonney, Development of Low VOC Polyurethane Foam Formulations for the Automotive Market based on Catalytically Active Polyols. UTECH Sonney, J.-M., Casati, F.M., Dawe, R.D., Khameneh, K.N, Jones, T., Olari, J., Fielding, P. (2002) Recent Advances in the Development of Catalytically Active Polyols for the Auto-motive Market, Proceedings of the Polyurethanes Conference 2002; Technomics: Lancaster, PA Patent WO 02/22702 A1, Polyols with autocatalytic characteristics and polyurethane products made therefrom, Casati, F. M., Sonney, J.M., to The Dow Chemical Company, March 21, Casati, F.M., Herrington, R.M., Sonney, J.-M., Tu, J., Mispreuve, H. and Fanget A. (2001), Elimination of Amine Emissions from Polyurethane Foams: Challenges and Opportunities, Proceedings of the Polyurethanes Conference 2001; Technomics: Lancaster, PA Patent WO 01/58976 A1, Low emission polyurethane polymers made from autocatalytic polyols, Waddington, S., Sonney, J.M., Elwell, R. J.; Casati, F. M.; Storione, to The Dow Chemical Company, August 16, 2001

17 Sabrina Fregni Sabrina Fregni is Senior Development Chemist in Dow for Formulated Systems. She holds a degree in Chemistry from the University of Modena (Italy, 1995). In May 1997 she joined Dow in the PU Systems Global R&D Center in Correggio (Italy) with project responsibilities in research and development for flexible polyurethane foams applications especially for what concerns the transportation and furniture industries. She is leading the development of Polyurethane Foams in Automotive applications. Alain Fanget Alain Fanget joined the Geneva-based Polyurethane Research and Development Group of Union Carbide Europe in 1978 and was then transferred to BP Chemicals in 1979 and to The Dow Chemical Company in 1989 where he worked in various PU molding and ACES applications. He is currently a Senior Application Development Specialist in the Automotive Systems TS&D Group in Horgen / Switzerland, with specific responsibilities in seating and NVH molding applications.