Polyol base level

These full synthetics have been all PAO or ester based, and a mixture of ester plus PAO. The addition of PAO or ester to petroleum based engine oils for improved oxidative stability has shown average quality results. The addition of lower levels of PAO or ester base stock <15 wt % to petroleum based formulations show little or no improvement in the thermo-oxidative engine test. The predominant automotive synthetic base stocks (PAO, diesters, polyol esters) do not show any hydrolytic instability in engine oil applications. 

The above cited diol, when incorporated into a flexible polyurethane foam formulation at a 5.6% level (10 phr based on the polyol) produced a self-extinguishing urethane foam, based on the Motor Vehicles Safety Standard 302 Flammability Test. 

Effect of Oxyethylene Content on Stability. The processing instability of TPU elastomers based on PPG 2000 can be overcome by the use of ethylene oxide "tipped" PPG polyols, especially those containing high levels of oxyethylene groups, e.g., 30% to 45% by weight. The improved stability of the polymers based on such polyols is demonstrated in Table 2. 

In the history of PU, some continuous processes for polyether polyol synthesis by anionic polymerisation were developed, but only at small scale (i.e., pilot plant). Tubular reactors with static mixing systems or a column with plate reactor types were used, but these technologies were not extended to industrial scale levels. The first continuous process for high MW polyether synthesis was developed by Bayer (IMPACT Technology) and is based on the very rapid coordinative polymerisation of alkylene oxides, especially PO, with dimetallic catalysts (DMC catalysts - see Chapter 5). A principle technological scheme of a polyether polyol fabrication plant is presented in Figure 4.30. 

Three microemulsions liquid crystalline gel formulations from Croda, Inc. based on lower EO nonionic surfactants and ethoxylated phosphates for clear hair gel products are shown inTable 6 [15]. One contains cyclomethicone for reduced oily feeling, and another contains a high level of polyol for humectant effect, classifying it as a curl activator. 

Use Level 1-2% (on polyol component, added to hardener component) Storage Store in a cool, dry place 2 yr max. shelf life when kept in the original, unopened container EFKA -3883 [EFKAAdditives BVj Chem. Descrip. Polysiloxane-based... 

Properties of hybrid dispersions prepared according to the different methods (la, lb and 2 - see Section 6.3.2) and based on the same polyol (PTMG 2000), but differing in the presence or absence of double bonds in the polyurethane-urea part of the hybrid, as well as of films and coatings made of them, are presented in Tables 6.21 and 6.22. All dispersions have a similar low level (2.0-3.3%) of coalescent and have the same structure of the acrylic/styrene part of the hybrid. Redox initiator was used in the synthesis of dispersions according to the method 2, and in all other dispersions presented in these tables a water-soluble initiator was applied. 

In this work, MDI-terminated polyester prepolymer based on ethylene adipate polyol (Baytec MS-242) was used to prepare cast poly(ester urethane) materials. The HER-TG materials, HER-HP and HQEE were used as chain extenders. As discussed in section 8.4, technical grade HER materials contain various levels of high MW diols as reactive impurities. Therefore, as with poly(ether urethanes), the high MW diols are expected to play a major role in the performance of poly(ester urethanes) made with these materials. 

A review of the elastomer processability and physical property data indicates that there is an optimum hardness range for each polyol MW. Based on the demould time and the percent compression set, the following elastomer Shore hardness ranges are recommended. The lower hardness limits of these ranges can be extended by addition of low levels (less than 10%) of 6000-MW, ultra-low monol triol (Acclaim Polyol 6300). 

Table 9.21 illustrates this effect by increasing the PPG MW from 2000 to 4000 and the prepolymer % NCO from 6 to 8. This increases the hardness to the same level as the PTMEG-based elastomer and increases the rebound to 65%. As an aside, increasing the prepolymer % NCO from 6 to 8 represents a polyol/BDO blend of 2160 MW. 

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