【正文】 3). See the gaskets (4) fitted at the bottom of the mixing cylinderPhase 2: Metering and mixing of the ponents in the mixing cylinder。This draws shows the four ponents metered and blended in the mixing cylinder (1), always kept against the bottom of the mould (2).Phase 3: Distribution of the reactive mixture inside the mould。In phase 3, when the mixing is over, the mixing cylinder is released and moves slightly upwards to get a nonsplash distribution of the reactive mixture (1) in the mould.Phase 4: Rising of the reactive mixture and block squaring。 During the foam rising (phase 4) the mould is moved to the squaring station, soon after the antidripping system (3/1) closes the bottom of the mixing cylinder thus preventing drops of the reactive mixture splits the foam. After a set, technical time, the vacuum and/or pressure within the enclosure is taken off and the mould is brought back to atmospheric pressureIn some producer39。s plants the phases 2, 3 and 4 occur inside an enclosure where the desired vacuum or pression values have already been reached and kept constant.To better illustrates all these phases, kindly refer to the attached sketches. Phase 1: Positioning of the mixing cylinder in the Phase 2: Metering amp。 mixing of ponents in mix cylinder the mould box Phase 3: Distribution of the reactive mixture inside Phase 4: Rise of reactive mixture/antidrip the mould insertion/block squaringFOAM MECHANICAL CHARACTERISTICS Table 2. illustrates the mechanical characteristics of the foams obtained using the same formulation shown in Table 1. but under different atmospheric pressure conditions.Table 1. Formulation Used in Table 2Conv. Polyol or polymeric polyol100H2OAdditivesMethylene Chloride or other BA TDIIndex 110Absolute pressure mbarRefer to Table 2Density kg/m3Refer to Table 2 The controlled pressure flexible foam technology does not need any Blowing Agent.Table 2. Foam characteristicsPressurembarDensity[g/l]Hardness 40 %[daN]CLD 40%[kPa] 50 %[%]Tensile strength[%]polymeric polyol 1000polymeric polyol 850polymeric polyol 650Conv. Polyol1000Conv. polyol850145Conv. polyol650139CONCLUSIONSLow density foams produced by using CPT (Controlled Pressure Technology) have proved to be the most petitive technology being costeffective and having better physical mechanical properties pared to other ones. Formulation Saving CostsConsidering the cost per kg of the foam, there is a remarkable saving in very low density foams (15 – 16 g/l) since by adopting CPT technology the vacuum replaces the use of blowing agents. Moreover, lower quantity of water is needed in the formulation pared if atmospheric pressure technology is used. This result in less quantity of TDI 80/20, which is a pretty expensive chemical ponents. Physicalmechanical PropertiesAnalyses on the foam properties, especially its hardness which is of the utmost importance in low density foams, have proved CPT successful.The low pressure effect has a scant influence on foam hardness pared with conventional blowing agents.A positive aspect is the possibility of introducing fillers in the foams, achieving easily a better hardness and a lower formulation cost.Since Liquid Carbon Dioxide (LCD) systems are provided with filters, these fillers cannot be used.The CPT has overe this drawback and is environmentallyfriendly since it does not require additives with . and/or .Emissions of Isocyanate and Amine gases developed by the reactive mixture are retained by Activated Carbon Traps prior to being realised to the atmosphere. Since this CP foaming equipment is encapsulated in an airtight tunnel, the process is absolutely environmentally friendly and dangerfree for both the environment and the workplace.BIOGRAPHYGiorgio Pallanza Mr. Giorgio Pallanza born in 1972, doctor of chemical engineering. He has worked in the field of PU systems as technical marketing manager. He joined OMS in 2001, now is the sales area manager for Far East markets.Vittorio Mariani Mariani has doctor degree of industrial chemistry, he is one of the founders of OMS Group and has been since then involved as Ramp。D Manager. He started his activity in the polyurethane field as continuous slabstock foams production manager.403 / 16