Pour-in-place foams

The frothing process was developed by the Du Pont Co. (25). The process has the following advantages isotropic physical properties and lower foaming pressure. The method is preferably used for large-panel production at in-plant production or pour-in-place foaming in field applications, e.g., building panels, chemical tanks, etc. 

Flexible urethane foams include slabstock foam, molded foam, and pour-in-place foam. In some cases, the latter two foams can be called flexible RIM foams (RIM is an abbreviation for reaction injection molding). 

Economics. Rigid foam systems are typically in the range of 32 kg/m (2 Ib/ft ) and, are typically about 30-40% higher in price than the pour-in-place foam systems because of differences in raw material costs and process. Unit prices for pour-in-place polyurethane packaging systems fall between the competitive expandable polystyrene bead foam and low density polyethylene foams. 

Chem. Descrip. Polysiloxane-polyether copolymer surfactant Uses Foam stabilizer for mfg. of rigid PU foams, continuously laminated PU board-stock, pour-in-place foams, rigid block foams Properties Cl. vise, liq. dens. 1.055 0.01 g/cc vise. 450 120 mPa-s solid, pt. < -15 C hyd. no. 120 12 cloud pt. 64 3C (4% aq.) pH 6.5 1.5 (4% aq.)... 

The product contains 12.6% phosphoms and has an OH number in the 450 mg KOH/g range. Fyrol 6 is used to impart a permanent Class 11 E-84 flame spread rating to rigid foam for insulating walls and roofs. Particular advantages are low viscosity, stabiHty in polyol—catalyst mixtures, and outstanding humid aging resistance. Fyrol 6 is used in both spray foam, froth, pour-in-place, and slab stock. 

CeUular polymers are also used for pipe and vessel insulation. Spray and pour-in-place techniques of appHcation are particularly suitable, and polyurethane and epoxy foams are widely used. Ease of appHcation, fire properties, and low thermal conductivity have been responsible for the acceptance of ceUular mbber and ceUular poly(vinyl chloride) as insulation for smaller pipes. 

Monofunctional, cyclohexylamine is used as a polyamide polymerization chain terminator to control polymer molecular weight. 3,3,5-Trimethylcyclohexylamines ate usehil fuel additives, corrosion inhibitors, and biocides (50). Dicyclohexylamine has direct uses as a solvent for cephalosporin antibiotic production, as a corrosion inhibitor, and as a fuel oil additive, in addition to serving as an organic intermediate. Cycloahphatic tertiary amines are used as urethane catalysts (72). Dimethylcyclohexylarnine (DMCHA) is marketed by Air Products as POLYCAT 8 for pour-in-place rigid insulating foam. Methyldicyclohexylamine is POLYCAT 12 used for flexible slabstock and molded foam. DM CHA is also sold as a fuel oil additive, which acts as an antioxidant. StericaHy hindered secondary cycloahphatic amines, specifically dicyclohexylamine, effectively catalyze polycarbonate polymerization (73). 

Las Vegas, Nv., 20th-23rd Oct. 1996, p. 179-89. 43C6 LOW DENSITY ALL WATER-BLOWN RIGID FOAM FOR POUR-IN-PLACE APPLICATIONS Kaplan W A Neill P L Staudte L C Brink C J Stepan Co. 

The dimensional stability of low density, water blown rigid PU foams for pour-in-place thermal insulation applications was improved by the use of a phthalic anhydride based polyester polyol containing a dispersed cell opening agent. The foam systems obtained allowed some of the carbon dioxide to be released through the cell windows immediately after filling of the cavity, and to be rapidly replaced by air. Studies were made of the flowability, density, open cell content, dimensional stability, mechanical properties, thermal conductivity and adhesion (particularly to flame treated PE) of these foams. These properties were examined in comparison with those of HCFC-141b blown foams. 21 refs. 

Process and Equipment. Rigid polyurethane foam processes use Ihe same high or low pressure pumping, metering, and mixing equipment for flexible foams. Subsequent handling of the mixture is determined by the end product desired. Processes include lamination, pour-in-place, molding, bun stock, box loams, and spray. 

The bulk of the ngid polyurethane and polyisocyanurate foam is used in insulation. See also Insulation (Thermal) More than half (60%) of the rigid foam consumed in 1994 was in the form of board or laminate die remainder was used in pour-in-place and spray foam applications. 

More than 50% of the rigid polyurethane foams manufactured in the United States in 1994 are used in the construction industry (Table 10). About 60% of the total rigid foam is used in laminated boards and insulation panels about 30% is poured in place. Insulated appliances is another important use of rigid insulation foam. 

In addition, this system has been modified by adding dibenzyl sorbitol to give high thixotropicity to the system to prevent penetration of the system into foam cells. For these reasons the foam system is very suitable for pour-in-place application into small foam voids, e.g., 1 to 10 cm, for repairing surface air voids of molded automotive-foam seats to reduce the rejection rate, thereby resulting in lowering production costs. 

TDI Prepolymer Process. This process has the major advantage of better flowability in pour-in-place processes, e.g., household-refrigerator insulation, than crude TDI-based or polymeric MDl-based processes. An example of TDI-based prepolymers and a formulation for making rigid urethane foam on a small scale is shown below. 

Foam-In-PIace. The foam-in-place (or pour-in-place) method is used for the production of refrigerators, deep freezers, sandwich panels, and similar applications. This process is also used for field applications, such as indoor- and outdoor-tank insulation (79), LPG (liquefied petroleum gas) tank insulation, heavy oil-tank insulation, chemical-tank-car insulation, and pipe-covering insulation, among others (79). 

The commercialization of simUar foams was followed by Hexaform (trade name ICl) in 1968 (57). The commercialization was later followed by Upjohn Company (trade name Kode 25) and Jim Walter Corp. (trade name Thermax). Foaming methods of modified-isocyanurate foams include slabstock, laminate, block, pour-in-place and spraying. 

The frothing process is widely used in rigid urethane foam pour-in-place applications. The frothing process of urethane-modified isocyanurate foams has been used for the insulation of petrochemical plants, e.g., spherical tanks, reaction towers, etc. (79). An example of the frothing system is shown below (71). 

The use of this catalytic system permits foam formation to proceed without the need to supply external heat to the reaction mixture after the reactants are brought together. This permits pouring-in-place of the foam-forming system, for example, in the insulation of cavity walls for construction purposes, in trailer walls, and in cold-storage firameworks and the like. 

It has been proved that pyranyl foams can be used for pour-in-place applications in household refrigerators and deep freezers. Furthermore, because of their high thermal stability the foams can withstand inunersion in molten asphalt at 205°C (400°Q. This jn-operty makes possible applications to roof insulation with molten asphalt as a water-I otecting layer. Another possible application is the baking of the enamel finish on freezer cabinets after the foam insulation has been applied. The foaming reaction is very fast, and, therefore, spraying of the foams onto out-door tanks and pipes is possible. 

There is no sharp line of demarcation between the manufacturing methods described in this chapter. For example, some writers consider "foam-in-place" or "pour-in-place" varieties of molding. The technique of "frothing" may be used in "pour-in-place" methods. Slab stock prepared by continuous slab production is used in lamination (1). 

Isomate [Pfizer], TM for isocyanate foam systems. Available as nonbuming, pour-in-place froth, or spray foams. 

Autopak. [Olin] RigitPflexibte foam system (pour-in-place) for pre-mold pkg. 

Chem. Descrip. Tetrabromophthalatediol CAS 20566-35-2 EINECS/ELINCS 243-885-0 Uses Flame retardant for rigid urethane and urethane-modified isocyanurate foams for UL and factory mutual class 1 and 2 specs, slab stock, pour-in-place, and spray foams, urethane coatings and elastomers... 

It was mentioned earlier that foams are anisotropic. This is due to unequal internal and external forces acting in the three perpendicular axes during foam rise. The results are elongated cells, as shown in Fig. 3(b). In certain circumstances, such as molded PS beads, the anisotropy may be minimal. The following discussion will often include references to the parallel ( )and perpendicular (J ) foam axes. It should be understood that these specimen axes are usually only approximations and depend on container dimensions and resin viscosity. Only in the indicated area of the pour-in-place bun (shown in Fig. 5) is the rise direction reasonably vertical. An appreciable amount of the scatter found in foam-related data may be attributed to incomplete characterization of the specimen axis relative to the actual rise direction. 

Usable viscosity Reduced polyol cost 1 Useful for 1 Billets (boardstock), Pour-In-Place 1 High density High viscosity Foam very rigid Foam useful for Spray Thin section -Pour-In-Place i 1 I I 1 t... 

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