Polyurethane elastomers components

Metal salts of neodecanoic acid have also been used as catalysts in the preparation of polymers. For example, bismuth, calcium, barium, and 2kconium neodecanoates have been used as catalysts in the formation of polyurethane elastomers (91,92). Magnesium neodecanoate [57453-97-1] is one component of a catalyst system for the preparation of polyolefins (93) vanadium, cobalt, copper, or kon neodecanoates have been used as curing catalysts for conjugated-diene butyl elastomers (94). 

Where the polyurethane comprises <30% of the blend, the polyurethane remains in discrete droplets within the polyacetal matrix. In this range the particle size and particle size distribution of the elastomer particles are of importance. Where the elastomer component is in excess of 30%, interpenetrating polymer networks exist in the sense that there are two interpenetrating continuous phases (as opposed to two cross-linked interpenetrating polymer systems). 

Polyurethane elastomeric fibers, 205 Polyurethane elastomers, 201 Polyurethane foams, 20, 29, 202 preparation of, 251-252 Polyurethane formulations, one- and two-component system, 238-241... 

Crosslinking with glycols and diamines plays a major role in the preparation of polyurethane elastomers. The properties of the resulting products can be widely varied by choice of starting components and the number of crosslinks ( mesh width ). 

A family of elastomeric foams has been developed by Rand 129) for use as stress relief coatings on electronic components in encapsulated electronic assemblies. Polysulfide, silicone and polyurethane elastomers blended with glass and phenolic microspheres have been used to formulate syntactic foams (Fig. 10) These foams are used to minimize the stress caused by differential thermal expansion between the component and the encapsulant. 

The properties of some polyurethane elastomers, used as such as elastic damping components in engineering applications (e.g., in sheet stamping operations and for coating of press and other rolls of paper-making equipment18) are shown in Table 1.3. 

Flow sheets for preparing the components of various monomer and oligomer reactant mixtures do not differ significantly from each other, although they may have different sets of reactors. The choice depends mainly on the physical and chemical properties of the initial components. Fig. 4.2 shows a flow sheet for obtaining continuously molded polyurethane elastomers. Fig. 4.3 illustrates an elementary flow sheet for a batch process unit for manufacturing moldings of epoxy resin or epoxy-based composites filled with quartz sand. 

Gallagher Corporation. "Cast and Molded Components of Polyurethane Elastomers— Design and Application Guide." Trade Paper (1994) 35. 

Castable Polyurethane Elastomers explains the production process of polyurethane components from both the theoretical and practical points of view. It describes the underlying concepts for the raw material supplier recommendations and explains how to achieve application-specific properties in polyurethane. The book explains the production of prepolymers with special focus on health and safety issues. It presents the different types of methods available on both the micro and macro levels and explains the rationale behind choosing the system needed to create a cost-effective, application-specific product. 

Offering an inside look at the logic behind the formation of polyurethane components, Castable Polyurethane Elastomers enables material scientists, engineers, and chemists to understand the total production process and reproduce the procedures to achieve desired results. 

Polyurethane Elastomers. Linear polyurethane polymers dissolved in ketone solvents provide a very versatile group of adhesives. Good results are obtained without fillers or other ancillary components in the formulation (indeed, the polymers concerned often are not compatible with the modifying resins and plasticizers that have been used for some time in other types of adhesive). 

Comparison of Polymers 14 and 15 in Figure 9 shows fairly similar polymerizations up to the point of shortstop addition. The control, Polymer 5, was slower but alive and growing at 18 minutes of polymerization time, reaching a final torque value of 660 meter-grams. Its steady intermediate polymerizarion rate is seen to be characteristic of uncatalyzed thermoplastic polyurethane elastomer polymerizations based on low acid number PTAd while Polymers 14 and 15 formed faster than usual from such a low acid number polyester glycol component. 

Pellethane . [Dow] Polyurethane elastomers for automotive, health care (tubing, catheter components, trans- rmal patches) applies., in film or sheets as bladdos, liners, or belting in fabricated prods, for casters, athletic... 

U-2 CMC. [Perma-FIcx Mold] Two-component polyurethane elastomer and acclerator. 

Ureflex. [Flexible Prods.] Polyurethane elastomer systems fcx gaskets, o-rings, potted components, custom molded wtxk. 

A recent commercial blend of ABS contains thermoplastic polyurethane elastomer as the main blend component. The blend was introduced in 1990 by Dow Chemical Co., under the trade name Prevail . These blends characteristically exhibit low modulus (340 to 1000 MPa) and high impact strength at low temperamres, e.g. notched Izod values of 370 to 1500 J/m at -29°C. The TPU component of the blend imparts high toughness and also allows paintabihty without a primer. ABS component imparts heat resistance (for paint ovens) and good tensile strength in the blend. The blend is projected to find applications in the automotive markets, particularly as paintable, soft bumper fascias. Typical properties of commercial ABS/TPU blends are shown in Table 15.6. 

There are two important types of polymer in which an elastomeric and a glassy or non-crystalline rigid component are copolymerised. The simpler thermoplastic elastomers are usually triblock ABA copolymers with B as the elastomeric component and A as the glassy component, whereas the segmented polyurethane elastomers are multiblock copolymers in which alternate blocks are hard , i.e. relatively inflexible, and soft , i.e. relatively flexible. 

Hazardous Decomp. Prods. Heated to decomp, emits CO, CO2, NOx, hydrogen cyanide Storage Air- and moisture-sensitive store under nitrogen reacts slowly with water Uses In isocyanate-based adhesives component in polyurethane elastomers high strength backbone or crosslinking intermediate... 

Potassium phosphate tribasic automotive safety air bags Potassium perchlorate automotive underhood components Polyurethane elastomer, thermoplastic auxiliary, dye mfg. 

Polyurethane elastomer, thermoplastic tubing, food processing Polymethyl methacrylate tubing, medical equip, components Polymethyl methacrylate tung oil ingredient Rosin... 

PCL is commonly used in the manufacture of polyurethanes because of its imparting good water, oil, solvent, and chlorine resistance to the polyurethane produced. In 1934, Carothers et al. [103] prepared epsilon-caprolactone for the first time. Under the condition of heat epsilon-caprolactone is converted to a polyester of high molecular weight. The 1965, Magnus [104] published details of his study of effects of components and varying -NCO/-OH or -NCO/-NH2 group ratio on the low-temperature properties, hydrolytic and heat stability, and solvent and chemical resistance of the polyurethane elastomers. It was found that... 

The contribution which the different types of polar groups make to the properties of polyurethane elastomers depends in part upon their ability to enter into strong hydrogen-bonded associations. The substituted urea linkage, formed by the reaction of an isocyanate with an amine, is regarded as exceptional in its contribution to the physical properties, and it is therefore a preferred component in many bulk elastomers where the structural irregularity introduced by the use of a non-symmetrical diisocyanate or polyol is compensated by the strong urea interactions. 

Catalysts are essential components in the liquid injection moulding (LIM) or reaction injection moulding (RIM) processes. Prepolymer systems for solid polyurethane elastomers usually do not require catalysts, and if long-term hydrolytic stability is required in the final polymer their use is undesirable. 

---