Rigid foam markets

Sommerfeld, C.D. (1996) PUR rigid foam markets for building, in Processing Workshop on Rigid PUR Foams, 26/27/28 March at Netherlands Congress Centre, The Netherlands, Crane Communications, London. 

Rigid foam markets include the following industries ... 

Polyester Polyols. Initially polyester polyols were the preferred raw materials for polyurethanes, but in the 1990s the less expensive polyether polyols dominate the polyurethane market. Inexpensive aromatic polyester polyols have been introduced for rigid foam appHcations. These are obtained from residues of terephthaHc acid production or by transesterification of dimethyl terephthalate (DMT) or poly(ethylene terephthalate) (PET) scrap with glycols. 

The market is dominated by flexible foam applications (43% in the United States) and rigid and semi-rigid foam (29%). Cast elastomers (4%) and RIM elastomers (3%) have only specialised outlets. The remaining sizeable 21% of the market cover such diverse uses as thermoplastic rubbers, surface coatings, adhesives, sealants and synthetic leathers. 

We have already been introduced to polyurethane chemistry in Chapter 10, Section 2, where we used toluene diisocyanate (TDI) reacting with a diol to give a polyurethane. Polyurethanes derived from MDI are more rigid than those from TDI. New applications for these rigid foams are in home insulation and exterior autobody parts. The intermediate MDA is now on the Reasonably Anticipated to Be Human Carcinogens list and the effect of this action on the market for MDI remains to be seen. The TLV-TWA values for MDA and MDI are some of the lowest of the chemicals we have discussed, being 0.1 and 0.005 ppm respectively. 

Rigid foams are based primarily on polyfunctional, low molecular weight alcohols and amines. Most global applications conventionally use polymeric isocyanates, TDI, or an undistilled grade of mixed TDI isomers. TDI prepolymers which have hydroxyl and isocyanate groups have been marketed as a low vapor pressure alternative to undistilled TDI. Density reduction is effected via the addition of chlorofluorocarbons, low molecular weight alkanes, or via the in situ generation of carbon dioxide. The resultant closed cell foams find applications as insulators in construction, appliance, transportation, pipeline, and tank end uses. 

Even though most plastics can be made into foamed products, from a practical and market oriented view only a few different types are used. A few of these plastics will be reviewed. As an example limited use has been made using cellular cellulose acetate (CCA). The CCA was one of the first rigid foams produced and was used rather extensively during the 1940s and 1950s mainly in aircraft sandwich constructions. 

Polyurethane rigid foam insulation also can be applied as a spray system to a variety of surfaces. Retro-fitting commercial roofs as well as insulation of tanks and pipes has had increasing acceptance. The next decade will require even further conservation of energy in all manufacturing facilities, and provide an ideal market for sprayed rigid foam insulation. By the end of this decade, the demand for spray systems could readily double the current level. 

Mexican urethane demand has been constrained by raw materials costs. Flexible foam markets will show some strength in the 80 s, reflecting a steady auto production and moderate increases for furniture and bedding uses. Rigid foam applications are still in the early stages of market development but, commercial/industrial insulation uses are increasing well. Mexico leads Latin America in urethane elastomer usage, paced by its demand for shoe sole applications. 

There is also interest in using polyurethane foam for the insulation of LNG tankers. These ships use high-density rigid foam (up to 100 kg/in ) and require significant quantities per tanker. Countries with well established ship building industries are vying for this market. 

The PRC markets for polyurethanes are centered in a range of applications from conventional flexible cushioning and rigid foam insulation to more sophisticated uses, such as shoe soles, synthetic leather and gymnasium playing surfaces. While statistics are not readily available, the PRC consumes about 10 million pounds of rigid foam and 8 million pounds flexible foam annually. Recent plans to build a 3 million in per year poromeric polyurethane synthetic leather plant should give impetus to polyurethane demand in 1982/83. 

Based on the numbers in Figures 1 and 2, by 1985 RIM and RRIM will require approximately 50 M lbs. of monomeric MDI, which is about one-third of the monomeric MDI supply in 1985 (Table IX based on 20-25% of 85% nameplate capacity, excluding ARCO capacity, = 137-171 M lbs. monomeric MDI). This will leave about 100 M lbs. of monomeric MDI for cast elastomers, thermoplastic polyurethanes, shoe soles, semi-rigid foams, and some adhesives and sealants, a monomeric MDI supply which should be more than sufficient for these applications. As RRIM grows, a need for capacity expansion can be seen in the late 1980 s. No effects on the market will be seen from PUR-SMC until after 1985, and at the present time meaningful projections are impossible. 

What kind of stakes are involved A 1979 "Outlook" annual market survey by the Upjohn Company indicates that the total United States market for polyurethanes would be 2,1+1+1+ million pounds including 1,1+50 million pounds for flexible foam, 615 million for rigid foam and 379 million for elastomers, coatings and adhesives. 

Thesecompounds, widely employed at the outset of the development of polyurethanes have been displaced from their market by polyether-polyols. For the production of rigid foams however, use is still made of aromatic polyols produced by the transesterification of dimethyl terephthalate by glycoL... 

Due to the low cost, the excellent physico-mechanical properties of the resulting urethane - isocyanuric foams, thermal and fire resistance and low level of smoke generation, the most important applications of aromatic polyester polyols are for rigid PU/PIR foams in the boardstock market (continuous rigid foam lamination) and for building insulation. 

A number of "crude" isocyanates (polymeric isocyanates), undistilled grades of MDI and TDI, are available in the market. Some of these products, such as various forms of crude MDI, have a functionality varying between 2 and 3. They have a lower reactivity and a lower vapor pressure than the corresponding pure isocyanate. They have found extensive use in one-shot rigid foams. However, they are also employed in coating, sealant, and adhesive applications. The Upjohn Chemical Division has published an excellent bulletin on the use and precautions in handling isocyanates, polyurethanes, and related materials (13A). 

Other growth areas among rigid foams eire in the furniture industry (high density foams) and in packaging where in most cases very low density foams (0.5 - 1.0 Ib/cu ft)are being used. More recently, rigid urethane foams have been utilized in the manufacture of structural foams (3 ), and this market promises to be a major factor in the future. 

The principal use of rigid foam in the transportation market is for insulation of refrigerated truck trailers and bodies as well as refrigerated rail cars. The liquid urethane ingredients are usually poured into large panels held in a fixture. These are then used as integral components walls, roofs, or floors of the trailer or rail car. Additional uses are insulated truck bodies, recreational vehicles, and cargo containers. 

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