Polyurethane manufacture

Boeniger ME. 1991. Air concentrations of TDl and total reactive isocyanate group in three flexible polyurethane manufacturing facihties. Applied Occupational and Environmental Hygiene 6(10) 53-63. 

We have focused our attention on the prepolymer method for polyurethane development because we feel that it offers the researcher the greatest control of the molecule. We hope to encourage the scientific community to investigate other nonclassical polyurethane tools. If the pin posc of a device is purely physical, the large polyurethane manufacturers and chemists are the best resources for expertise. If, however, the intent is to experiment with a new polymerization technique for a particular medical or environmental application, the researcher must be able to assemble the component parts along lines with which the polyurethane industry may not be familiar. 

Flexible polyurethane manufacturing Pouring line 120-260 Boeninger(1991)... 

Boeninger, M.F. (1991) Nonisocyanate exposures in three flexible polyurethane manufacturing facilities. Appl. occup. environ. Hyg., 11, 945-952... 

Pruckmayr, G. "FTIR in Polyurethane Technology." Paper presented at the Polyurethane Manufacturers Association, Portland, Oregon, 10/19/1993. 

Rollers of all shapes and sizes canbe made from polyurethanes. They vary from very soft printing rollers to hard rollers used in the steel industry. The casting and trimming of these rollers are very suited to polyurethane manufacturing. 

PVC can be blended with numerous other polymers to give it better processability and impact resistance. For the manufacture of food contact materials the following polymerizates and/or polymer mixtures from polymers manufactured from the above mentioned starting materials can be used Chlorinated polyolefins blends of styrene and graft copolymers and mixtures of polystyrene with polymerisate blends butadiene-acrylonitrile-copolymer blends (hard rubber) blends of ethylene and propylene, butylene, vinyl ester, and unsaturated aliphatic acids as well as salts and esters plasticizerfrec blends of methacrylic acid esters and acrylic acid esters with monofunctional saturated alcohols (Ci-C18) as well as blends of the esters of methacrylic acid butadiene and styrene as well as polymer blends of acrylic acid butyl ester and vinylpyrrolidone polyurethane manufactured from 1,6-hexamethylene diisocyanate, 1.4-butandiol and aliphatic polyesters from adipic acid and glycols. 

Diphenylmethane diisocyanate (MDI) is another important raw material in polyurethane manufacture. It is a solid, melting at 37°C, and has a tendency to dimerise at room temperature. Several other aromatic isocyanates are used in the preparation of polyurethanes but are not widely used. Various aromatic isocyanates are illustrated in Figure 2.14. 

These grades or concentrations are used in the production of ammonium nitrate, which at present consumes some 65-75% of the total nitric acid made [44], as well as for many other minor uses. Some of these are, for example, adipic acid production (5-7%), military and industrial explosives (3-5%), isocyanates for polyurethane manufacture (1-2%), nitrobenzene (1-2%), and potassium nitrate preparation from the chloride (about 1%). Many smaller scale uses consume the remaining 10-15% of the acid produced. 

In an ironic aside, it is noted that the most recently suggested new use for phosgene is to "make safe" thousands of tons of TNT (2,4,6-trinitrotoluene) from redundant weapons, no longer required now that the Cold War has ended. Treatment of the TNT with ammonium sulfide would reduce it to 2,4-diamino-6-nitrotoluene, which could then be treated with phosgene to give 2,4-diisocyanato-6-nitrotoluene (NDTI), a potentially valuable precursor for polyurethane manufacture [64d]. Thus, instead of potentially hazardous, and certainly wasteful, destruction of the TNT, the use of phosgene could convert it into a valuable industrial commodity. 

Reaction of an isocyanate with an alcohol gives the corresponding urethane. This reaction, which forms the basis for the important poiyurethane manufacture, is illustrated in its simplest form in Equation (4.6). For polyurethane manufacture the alcohol (or polyol) and isocyanate reactants must of course contain, respectively, at least two functional groups. 

The chemistry and associated background to polyurethane manufacture and usage has been recently covered in The ICI Polyurethanes Book [2209a]. 

The radical containing an hydroxyethyl group which is formed (9.5), initiates the formation of polymeric chains which, by recombination, give hydroxy-telechelic polymers (reactions 9.6 and 9.7). Based on the principles mentioned various hydroxy-telechelic polymers were obtained by radical polymerisation of styrene [9], acrylonitrile [10], butyl acrylate or butadiene [10-14]. Of course, the oligo-polyols derived from styrene and acrylonitrile are solid and difficult to use in PU, but butyl acrylate and butadiene lead to liquid polymers with terminal hydroxyl groups, which are useful in polyurethane manufacture. 

Polyurethanes are obtained by the reaction of an oligomeric polyol (low molecular weight polymer with terminal hydroxyl groups) and a diisocyanate (or polyisocyanate). The structure of the oligomeric polyol used for polyurethane manufacture has a very profound effect on the properties of the resulting polymer. 

Two sealants were shown to have the most flexibility or toughness at 76 K and were subsequently used as the basis for modification studies to improve their low-temperature mechanical and physical properties. One was a polyurethane manufactured by duPont and designated Adiprene L-100. The other was a silicone manufactured by General Electric having both methyl and bulky radicals on the polymer backbone and designated RTV X-511. These sealant formulations were prepared and cured as shown in Table I. 

PHB photochemical hole burning (spectro- PMA Polyurethane Manufacturers Associa-... 

Polyurethane Manufacturers Association Spring Meeting Contact (630) 858-2670 or fax (630) 790-3095. 

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