An Improved Fire Resistance Polyurethane Foam And Process For Preparing The Same

The present invention relates to an improved fire resistance polyurethane foam and process for preparing the same which is used mainly in automobiles. For many years PUF is considered as an important material for use in acoustical insulations and is widely used in automobiles but not limited to , for the propose of acoustical insulation of passenger and engine compartment which is formed in complex 3 dimensional shape with variable thickness across the part. In recent years PUF is being used in Heavy Vehicles such as trucks, buses, Farm Equipment and Off Road vehicles as engine noise insulations to meet the government regulation of acoustical requirement. As the regulations are getting stringent with time , industry is experiencing more use of this material. Flame retardant polyurethane foams containing biuret linkages are known in the art of WIPO Publication no. WO 2011073355 20110623. According to said specification no. WO 2011073355 20110623 Flexible polyurethane foam is used in a wide range of cushioning applications. Among these are cushions for various types of seating products. These seating products may be, for example, home furnishings such as chairs, sofas, recliners, benches, chaises, ottomans, and similar products. Other seating products include cushioned furniture for office or institutional use, as well as seats for automobiles and other vehicles. A typical product of this type will include one or more polyurethane foam cushions that are covered with some fabric.

These polyurethane foams are generally characterized as elastomeric or "flexible" by virtue of being easily compressible and, "resilient", in that, when a compressive force is removed, the foam recovers its original shape rapidly and with force. These attributes are usually expressed quantitatively as "indentation load deflection", which measures the force needed to compress the foam by a specified proportion of its original thickness, and by a ball rebound test, in which a ball is dropped onto the foam from a specified height, and the height to which the ball bounces is measured. Flexible polyurethane foams for seating applications generally exhibit a value of at least 40% and more typically at least 50% on the ball rebound test of ASTM D3574. Polyurethane foams, being organic materials, are susceptible to combustion, and their cellular nature compounds this problem because of the ease with which oxygen and heat can permeate the foam to support the combustion process. This flammability is a very significant safety concern, and as a result many jurisdictions have specified that these foams, or furniture made from them, pass certain flammability tests. The tests vary from jurisdiction to jurisdiction. A major disadvantage of use of conventional PUF is observed that when they are used near or close to engine, especially in case of but not limited heavy vehicle, under service condition there is a high risk of fire hazards as conventional PUF is not fire resistant and is not self extinguishing , thus acting as a fuel to fire in case of any fire hazard , causing great threat to human life and vehicle. These disadvantages are overcome by the polyurethane foam of present invention which is referred to as PUF0

The main features of this invention of PFRO is having the following properties: a) Fire resistance , showing no burn rate and self extinguishing b) No dripping of material when subjected to direct flame or fire c) Does not loose its acoustical property d) Formable in conventional PUF process equipments e) Formed to required shape and sizes, with variable thickness f) Can be prepared with a density range of 60 kg/m3 to 140 kg / m3 for flexible or soft PUF . g) Can be prepared with a density range of 80 kg/m3 to 650 kg / m3 for rigid PUF h) Can be used as part of composite material with different carrier material where ever required with plastics such as but not limited PP , PE , rubber such as but not limited EPDM ,EVA ,Thermoplastic rubber and also but not limited to fiber reinforced resins and metals such as but not limited to Aluminium, Steel. i) As per requirement PFRO can also be laminated with different materials such as but not limited to non woven cloth, PVC film, Aluminum Film . To assist with the understanding of the invention explanation of the invention will now be made as below . Commercially available PUF system having materials namely Polyol and Isocyanate TDI or MDI type is mixed with fire retardant chemical mainly composed of expandable carbon allotrope hereafter referred as FFU2 . A typical combination but not limited to , in the ratio of materials in parts by weight are, Polyol 50 to 140 , FFU2 15 to 60 and Isocyanate 40 to 140 FFU2 controlled parts by weight is mixed with Polyol controlled parts by weight under constant slow speed stirring and controlled temperature . There

after Polyol FFU2 mixture is mixed with Isocyanate TDI or MDI with an usual combination of parts by weight but not limited to of Polyol 50 to 140 and Isocyanete 40 to 140 , under controlled temperature . The mixing of Polyol FFU2 is done in high speed stirring . The mixture is poured into a pre fabricated mould through open or close pouring method . The compound is allowed to set in side the mould for a period of 2 to 20 minutes depending of the density, shape and dimensions of the part .After removal of the Foamed PU it is allowed to set at ambient condition for 2 to 24 hrs depending on density shape and dimension of part . The PFRO thus formed is then tested namely but not limited to tests such as acoustical property , density , fire resistance property, compression set , hardness. Fire resistance property when tested as per IS 15061 and FMVSS 302 shows a behavior of no burn rate and self extinguishing and no dripping of material According to the present invention there is provided an improved fire resistance polyurethane foam (herein after referred to as PUF0) which comprises:-combination of polyol, FFU2 and isocyanate by mixing FFU2 with polyol in a controlled parts by weight under constant slow speed and controlled temperature with isocyanated TDI or MDI under controlled temperature In the said process the ratio of materials taken in parts by weight are polyol 50 to 140, FFU2 15 to 60, isocyanate 40 to 140 In the said process polyol, isocyanate are mixed under control condition and mixing of polyol FFU2 is done at High speed stirring, the obtained compound to allowed to set inside the mould for a period of 2 to 20 minutes

depending upon the density, shape and dimension of the part of which same is required and after removal of foamed PU which is allowed to set at ambient condition for two to twenty four hours depending upon the density, shape and dimension of the part for wich polyurethane foam is required. The obtained polyurethane foam may be laminated with different materials but not limited to woven cloth PVC film and aluminium film. The obtained PUF is completely fire resistance yet it can be moulded to different shape and size with variable thickness as per requirements and may be used in engine compartment, near the engine and/or passenger compartment and the density range may vary from 60 kg/m3 to 300 kg/m3 as per acoustical property requirement. A typical test result of acoustical PFRO when tested as per IS 15061 is as below for fire resistance characteristics.: 1) Flame self extinguishing time of PFRO of different density range is as per Trend Chart

2) Burn rate when tested as per IS 15061 and FMBSS 302 is Zero (0), No Burn Rate and Self extinguishing

3) No dripping of the material when tested as per IS 15061 Sound Absorption Coefficient with normal incidence sound wave of typical acoustical PFRO as per ASTM E 50 as per Trend chrat 2

The polyeurethene foam of present invention is fire resistant ,no dripping PU Foam which can be used as moulded or formed shape with or with out variable thickness within the part used solely or as a composite with lamination of polymeric material mainly rubber based material commonly known as heavy layer or barrier or otherwise also with fiber based felt layer, as an acoustical insulation in automobile interiors of passenger compartment , as sound insulation for in cabin noise insulation components namely but not limited to Dash Insulation Inner , Under Carpet , Roof insulation etc and in engine compartment of heavy vehicles and off road vehicles as noise insulation with a carrier material such as plastic based material namely PP ,ABS , HMHDPE , PVC , Fiber reinforced metals, Metals , etc for engine compartment acoustical components made from exposed surface of PFRO can also be laminated with non woven fabric , thin aluminum foil as a protector to PFRO from external damages . For use in passenger car engine room acoustical insulation PFRO can be used solely or with a lamination of non woven fabric or Aluminum foil as protector to PFRO from external damages .

The PFRO is extremely useful for use in automobile as fire resistant acoustical insulation PU Foam , and finds a wide application especially in areas where in PU foam based acoustical insulations are prone to fire or flame hazards typically but not limited to cause of fire in engine room due to fuel spillage and or electrical short circuits .By using PFRO as an acoustical insulation if fire so generated in a vehicle will not be propagated or will not be adding to the intensity of fire , without compromising on the acoustical property, formability of PU foam based insulation .

WE CLAIM: 1. An improved fire resistance polyurethane foam (herein after referred to as PFRO) which comprises:-combination of polyol, FFU2 and isocyanate by mixing FFU2 with polyol in a controlled parts by weight under constant slow speed and controlled temperature with isocyanated TDI or MDI under controlled temperature 2. Process for preparing an improved fire resistance polyurethane foam (herein after referred to as PFRO) as claimed in claim 1, which comprises:-preparing combination of polyol, FFU2 and isocyanate by mixing FFU2 with polyol in a controlled parts by weight under constant slow speed and controlled temperature with isocyanated TDI or MDI under controlled temperature. 3. Process as claimed in claim 2, wherein the ratio of materials taken in parts by weight are polyol 50 to 140, FFU2 15 to 60, isocyanate 40 to 140 4. Process as claimed in claim 2 or 3, wherein polyol, isocyanate are mixed under control condition and mixing of polyol FFU2 is done at High speed stirring, the obtained compound to allowed to set inside the mould for a period of 2 to 20 minutes depending upon the density, shape and dimension of the part of which same is required and after removal of foamed PU which is allowed to set at ambient condition for two to twenty four hours depending upon the density, shape and dimension of the part for which polyurethane foam is required.

5. Process as claimed in any of claims 2 to 4, wherein the obtained polyurethane foam may be laminated with different materials but not limited to woven cloth PVC film and aluminium film. 6. Process as claimed in any of claims 2 to 5, wherein the obtained PUF is completely fire resistance yet it can be moulded to different shape and size with variable thickness as per requirements and may be used in engine compartment, near the engine and/or passenger compartment and the density range may vary from 60 kg/m3 to 650 kg/m3 as per acoustical property requirement.

An improved fire resistance polyurethane foam (herein after referred to as PUF) which comprises:-combination of polyol, FFU2 and isocyanate by mixing FFU2 with polyol in a controlled parts by weight under constant slow speed and controlled temperature with isocyanated TDI or MDI under controlled temperature and process for preparing the same which comprises preparing combination of polyol, FFU2 and isocyanate by mixing FFU2 with polyol in a controlled parts by weight under constant slow speed and controlled temperature with isocyanated TDI or MDI under controlled temperature.