Polyurethanes Formulations

Catalysts are almost always required in polyurethane formulations because the NCO-OH reaction is generally slow at ambient temperature. There are situations, however, where catalysts may not be necessary. For example, in allurea systems additional catalyst is often not needed for the highly reactive 1° and 2° amine coreactants used and because curing is facilitated by the high... 

Most polyurethane formulations are two-component systems, meaning they are made from two basic constituents which are mixed together and react to form the final polymer. The two components are an isocyanate (or isocyanate blend) and a polyol (or polyol blend). The isocyanate is often referred to as the A side and the polyol the B side , although some use the opposite convention. 

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... 

Polyurethanes have also been used for many years. They can be applied from a solvent such as perchloroethylene, but such solvents are increasingly under environmental scrutiny. An aqueous polyurethane formulation is normally applied by padding, followed by baking at 150 °C using sodium carbonate as catalyst. 

A two component polyurethane formulation was stored In the field In separate 208 liter (55 gal) vessels of 0.95 cm wall thickness and under a 0.35 to 0.9 MN/m (50-100 psl) over pressure. Upon demand the components are mixed and discharged to form a rigid foam re-... 

The polyurethane formulation Involved a proprietary crossllnkable system based on poly(propylene glycol) and methylene dllsocyanate (NCO/OH ratio = 1.0). For studies of viscoelastic, energy absorption, and fatigue behavior, the weight fractions of PUMA were 0, 0.25, 0.50, 0.75, and 1.0 for studies of tensile and tear strength, the ratios were 0, 0.10, 0.20, 0.25, 0.30, and 0.40. Reactants were mixed at room temperature, degassed, poured Into a mold, and cured at 60 C for 48 hr. 

Much work has been done on the incorporation of castor oil into polyurethane formulations, including flexible foams [64], rigid foams [65], and elastomers [66]. Castor oil derivatives have also been investigated, by the isolation of methyl ricinoleate from castor oil, in a fashion similar to that used for the preparation of biodiesel. The methyl ricinoleate is then transesterified to a synthetic triol, and the chain simultaneously extended by homo-polymerization to provide polyols of 1,000, 000 molecular weight. Polyurethane elastomers were then prepared by reaction with MDl. It was determined that lower hardness and tensile/elongation properties could be related to the formation of cyclization products that are common to polyester polyols, or could be due to monomer dehydration, which is a known side reaction of ricinoleic acid [67]. Both side reactions limit the growth of polyol molecular weight. 

This technique is universal and the inhibitor sleeve with the use of polyurethane (Formulation HTPB TDI BD 1 3.2 2) as a matrix and rayon thread as a reinforcement may also be similarly made for this purpose [292]. 

Trudell and our group, with the generous support of Dr. Hugo Jaurequi, conducted certain cell-culturing experiments on human hepatic cells. Since the effort was self-funded, the scope of the experiments was limited. Nevertheless, we felt we confirmed the viability of a specially designed polyurethane formulation as a substrate for cell growth. 

The batch process equipment used for preparing the components is essentially a set of reactors equipped with heaters and agitators. They operate under vacuum or in an inert gas atmosphere. One of the main requirements of the chemical molding process is the production of pore- and defect-free articles. The volatile products and moisture must be thoroughly removed from the reactant mixture. Moisture imparts porosity to the final articles due to evaporation and the chemical interaction of water with the components of the reactant system, for example, with isocyanates in case of polyurethane formulations. In some cases, moisture can also inhibit the polymerization process, for example, anionic-activated polymerization of lactams. Many monomers, particularly acrylic compounds, require removal of die inhibitors to increase their shelf-life. 

As an example, let us analyze mold filling with a model polyurethane formulation. Let the kinetics of curing be described by an equation with the self-deceleration term (as was discussed above). The following values of the parameters were used U = 49.1 kJ/mol ko = 3.8xl06 = 1.1 ATmax = 25.8°C where ATmax is the maximum expected increase in temperature for adiabatic curing. 

Additive flame-retardants may be more easily incorporated in polyurethane formulation. Several class of compounds have been used to improve flame retardancy of PU foams such compounds are halogen- (very often chloroalkyl-phosphate) or phosphorous-based compounds, although also other substances, like as EG, melamine, aluminum trihydrate and magnesium hydroxide, may be used. 

Polyurethane formulations cover an extremely wide range of stiffness, hardness, and densities. The performance properties of polyurethane can be widely modified by selecting appropriate raw materials, catalysts and auxiliary compounds, by employing various production methods and/or by employing various methods for further processing and/or for shaping the final products. Therefore, polyurethanes have wide applications such as elastomer, coating, adhesive, foam, and leather. 

Antimicrobials. 2-Bromo 2-nitropropane-l,3-diol and 2,4-dichlorobenzyl alcohol are effective biocides in polyurethane formulations. 

Research was conducted on the method of recycling polyurethane, formulation of recycled polyurethane-modified recycled polyester (RPUMRPE) and their mechanical and chemical resistance properties. 

Table 6.26 Conditions for second digestion of S1O2 additive in polyurethane formulations...

Use For a solvent and humectantin cosmetics, liquid soaps, confections, inks, lubricants, in polyester and polyurethane formulations. 

To increase the application time of polyurethane formulations, delayed catalysts are used, and this delay can be achieved by chelation of the organotin compound with mercaptans or dionate. Table 6.2.8... 

Most studies of the kinetics of the isocyanate-hydroxyl reacfion have been done in systems composed of monofunctional reactants in various solvents (2 ). Even in these ideal systems, which have little resemblance to the more complicated polyurethane formulations, the reaction mechanism and kinetics are not well understood especially for the catalyzed reaction. This coupled with the added complexities encountered in polyurethane systems requires empirical determination of kinetic data if conversion during polymerization is to be predicted. A few kinetic studies on simple polyurethane systems have been reported (3, 4 ). Infrared spectroscopy was used to measure reaction rates in low catalyst formulations (3) while adiabatic temperature rise methods have been used to study fast systems (3 4, 5 ). 

Mechanical testing of the polyurethanes was performed by a modified identation/shear method described by Parsons and Black.(11) Relaxed and unrelaxed shear moduli of these polymers were measured in a simulated body fluid environment and compared to moduli of rabbit and human articular cartilage. This is shown in Table V. These tests, in addition to viscoelastic measurements of those polymers, indicate that this new polyurethane formulation is an excellent candidate for synthetic cartilage fabrication. 

The reaction of isocyanate with water is more exothermic than the reaction with alcohols and the total heat release per mole of water is about 47 kcal/mol [1-3]. It is evident that one mole of water reacts with two -NCO groups, which is very important in order to calculate the correct quantity of isocyanate needed for polyurethane formulations. 

Primax. [Air Prods.] Modified UHMW-PE us in cast polyurethane formulations to impart increased abrasion resist, reduced coeff. of friction, improved tear str., reduced part dens. 

Rubiflex Polyurethane Systems. [ICI Polyurethanes] Formulated systems for molded flexible foam. 

NSC 406696 Suool B Tetramethylene 1,4-diol Tetramethylene glycol 1,4-Tetramethylene glycol. Curative, chain extender provides reactive H-source in prepolymer production used to provide hard segments in PU. Used as an intermediate and in polyurethane formulation in the hard segment as a curative. Crystals mp = 20.1° bp = 235° = 1.0171 Xm = 291 nm (e = 200, H2SO4) freely... 

On account of their insensitivity to solar radiation, some polyester resins are particularly suitable for weather-resistant topcoats (e.g.. facade claddings, blades of shutters and Venetian blinds, vehicle claddings, metal signs). Melamine-formulated paints are economical and have a well-balanced property profile. Polyurethane-formulated paints have an even better processability and weather resistance (colorfastness, chalking resistance) [2.92],... 

High molecular mass polyester resins, cross-linked with benzoguanamine and melamine resins, are particularly suitable for highly drawable. sterilization-resistant decorative stamping enamels [2.88], [2.89]. Low molecular mass polyester resins also exhibit good processability and sterilization resistance in polyurethane formulations. 

P.N. Shah, Y.H. Yun, Cellular interactions with biodegradable polyurethanes formulated from l-tyrosine, J. Biomater. Appl. 27 (2013) 1017-1031. 

Uses For polyurethane formulation for automotive hose and gaskets, tires, industrial belts, tank and pipe liners, floor and roof coatings, medical devices polyester modifier processing lubricant for PVC food-pkg. adhesives, polymers, rubber articles Manuf./Distrib. Aldrich Allchem Ind. BASF Great Fakes Monomer-Polymer Dajac Fabs... 

Figure 1.41 shows a variety of flexible moulded Dabco surfactants which can be utilised in TDI and/or MDI formulations. Using Figure 1.41, proper selection of the surfactant can be made, enabling polyurethane formulators to expand their processing latitude, cell openness, and bulk stability of the foam article in their critical formulations. 

Figure 32 The new Cannon Ax Head, specifically designed for multi-component polyurethane formulations. It can mix up to six chemicals all with a high-pressure...

An example where the requirements recently have changed, because of the appearance of environmental legal constraints, is the use of trichloromonofluoromethane as blowing agent in polyurethane formulations. This is a non-flammable, very stable solvent with an attractive price, which fulfils three major technical requirements of, in particular the rigid, polyurethane industry ... 

---