Polyols blends

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. 

Place Arcol Polyol F-3022 (100 g, 0.1 eq., 56 OH, mixed PO/EO triol from Bayer) into a suitable container. To this add distilled water (3.3 g, 0.4125 eq.), Niax Silicone L-620 (0.5 g, a silicone surfactant from OSi Specialties), and Niax C-183 (0.12 g, an amine catalyst from OSi Specialties). Thoroughly blend this mixture without incorporating air bubbles. Then add Dabco T-9 (0.25 g, stannous octoate from Air Products) and mix again. The T-9 must be added last because it is quite water sensitive, so its exposure to the water-containing polyol blend should be kept to a minimum. To this polyol blend, quickly add Mondur TD-80 (42.6 g, 0.4868 eq., a mixture of 80% 2,4-TDI and 20% 2,6-TDI isomers from Bayer) and immediately stir at 3000 rpm for 5 s. Quickly pour the reaction mixture into a suitable container such as a 1-qt paper or plastic cup and allow the foam to free-rise. The stir blade may be wiped or brushed clean. 

For the above polyol blend viscosity (Brookfield, ASTM D-2196) = 1500 mPa-S at 23° C. For the reaction mixture working (pot) life 20 min Gardner circular dry times [72°F, 54% relative humidity (RH)] surface dry = 1.0 h, hard dry = 2.0 h, mar free = 3.5 h. For the finished coating gloss (ASTM D-523) = 90+ at 60° impact (ASTM D-2794) = 60 in.-lb direct, 10 in.-lb reverse Tabor abrasion (ASTMD-4060,1000 g load, 1000cycles, CS-17 wheel) = 95.6 mg pendulum hardness = 180 s MEK double rubs (ASTM D4752-95, 50 double rubs) = softened. 

Fig. 2.9.42. APCI-FIA-MS-MS(+) (CID) product ion mass spectrum of [M + NH4]+ parent ion of 2,4,7,9-tetramethyl-5-decyne-4,7-polyol blend at m/z 640 (number of PEG...

For polyurethane production, Donnelly [109] has carried out the synthesis of copolyurethanes based on mixtures of commercial poly(THF diol)s with glucose. Complex products resulted, which can be represented by mono- or bis(glucoside) structures. From a variety of polyol blends, solid polyurethanes were prepared which ranged from linear, soluble, weak elastomers to polymers of higher transition temperature and stiffness, low solubility, and low extension under tensile load [110]. 

In this study, the use of a PM polyol as a rubber modifier for a highly crosslinked, polyurethane resin (T = 150 °C) was assessed again in comparison with an oil-based PB polyol. The polyurethane resin matrix was formed from pure MDI and a polyol blend comprising a polyoxypropylene triol, LHT240 (Union Carbide) of equivalent weight 227.6 g-mol"1, and trimethylol propane,... 

The former material was evaluated with and without Owens/Coming Fiberglas 737 milled glass whUe the latter resin was always shot neat, but evaluated with and without Owens/Coming Fiberglas M-8610 random mat in the tool. The stmctural polyol blend had a viscosity of about 1,780 centistokes at 77°F, and an extended gel time of about 15 seconds at the mold temperature of 140"F and component temperature of 100 F. The isocyanate had a viscosity of 200 cps at the same temperature. The A/B ratio was about 1 1. 

Polyurethane (PU) materials have been formed by RIM using a commercial isocyanate reacting with either various compatible or incompatible polyol blends, or with slurries containing polyol blends and glass fibres. 

Formulations for producing polyurethanes (PUs) by reaction injection moulding (RIM) usually contain mixtures of polyols and diols in order to achieve the desired properties in the moulded part. The present work forms part (1) of a systematic investigation into the effects of polyol blends and glass fibres on the physical properties of unfilled and filled PUs formed by RIM. In the case of unfilled PUs, by using a multi-component polyol mixture, it is possible to investigate the effects on properties of (a) polyol structure, molar mass and functionality, (b) the relative proportions of diol-based hard blocks and triol-based soft blocks and (c) polyol blend compatibility. The... 

Series II Unfilled PUs using various compatible polyol blends (PB) in which the code numbers in Table I represent in order the weight ratios of polyols T32/75, LHT240 and EG. A mixture of triethylene diamine and dibutyltin dilaurate was used as catalyst throughout. The various polyol-based reactants and derived RIM PUs are summarised in Table I, including isocyanate/hydroxyl ratios (multiplied by 100), expressed as the System Index. Thus, 1001 represents stoichiometric equivalence, 1041 a 4% excess by weighted equivalents of isocyanate and 971 a 3% excess of hydroxyl. 

Table I. Polyol Blends and Slurries Used with VM10 Isocyanate...

Polyol Blend/Slurry Viscosity(25°C) Poise Polyurethane from VM10 System Index... 

Effects of Plaque Thickness, System Index and Filler ( Filled materials formed using incompatible polyol blend PBA1478 at... 

Figure 3. Tensile stress-strain curves (23°C) of RIM PUs defined in Table I. PUs formed from isocyanate VM10 and (a) compatible and incompatible polyol blends (Series II) (b) incompatible polyol blends and slurries based on PBA1478 (Series I).

Figure 4. Variation of flexural modulus with temperature (-30°C to 65°C) for the RIM PUs in Series I and II defined in Table I. Curves show the effects on flexural modulus-temperature behaviour and -30/65°C ratios of polyol composition and added fillers, (a) Polyol blend compatibility/incompatibility Key A, PU221 A, PU421 , PU521 O, PU621 , PU821 , PU401.

Figure 5. The effect of polyol blend composition on the dynamic storage modulus versus temperature behaviour of the unfilled RIM PUs of Series I defined in Table I. (Key as in Figure 4 (a).)...

In the present investigation it has not been possible to undertake a systematic investigation of all the variables that might affect the viscosity of a glass fibre slurry, but an attempt has been made to identify the more important parameters. Polyol blends as described in a preceding paper in this volume (1) were used. Three specific aspects of rheological behaviour have been investigated. 

Figure 4. Flow curves for 1.5nun CSG dispersed in PBA1478. See (1) for specification of polyol blend PBA1478.

A basic similarity in the form of the pulses for F and T is found. This is consistent with the theoretical relation between P and T for adiabatic conditions Equation 11. Conformity with this equation was also shown by measurements on a polyol blend with two different capillaries, which gave a linear plot of AT against F. 

Sultanbawa, Y. and Li-Chan, E.C.Y. 1998. Cryoprotective effects of sugar and polyol blends in ling cod surimi during frozen storage. Food Research International 31 87-98. 

The blowing agent used to make PU foam is normally first blended with a polyol and then sprayed. As a result it has to be miscible with the polyol, and the flash point and flammability of the polyol blend has to be considered. Spraying foam for applications like factory roofs obviously has to be carried out on site and needs non-flammable materials that are safe to handle, whereas discontinuous metal panel spraying operations can be carried out in safer, purpose-built spray booths in factories, without the same fire risks. 

POLYOL BLEND USED AS AN EXAMPLE TO CALCULATE THE EQUIVALENT WEIGHT OF A MIXTURE OF POLYOLS AND CHAIN EXTENDER... 

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