Castor oil polyol

Transesterification of polyols results in castor oil polyols with lower or higher functionality. Oxidation of castor oil, by blowing air or oxygen through the oil, results in polymerization that yields products with increased viscosity, specific gravity, and saponification value of the oil. The bodied oils have been reported to be more useful in urethane coatings than the untreated castor oil (10). 

Closely related to the castor oil polyols are polyols derived from the transesterification of certain drying oils, such as linseed, oiticica, and soya oils. The mono- and diglycerides resulting from this reaction are then utilized in the manufacture of uralkyds. 

Surface-mount adhesives 35-50% epoxy resin, 1-10% amine or polyamine curing agent, and 10-30% mineral filler and thixotrope Mondur MC/castor oil and castor oil polyols (>60%), filler 5%) Eccobond 125F (Henkel), Epo-Tek 70E-4 (Epoxy Technology), Epi-bond 7275 (Cookson Electronics) Flexobond 442 (Bacon Industries)... 

Mondur MC/castor oil and castor oil polyols (>60%), filler (<5%) Flexobond 444 Bacon Ind. 

Using this technique, a large variety of polyurethanes have been prepared from different vegetable oils. Natural polyols like castor oil (generally trifunctional) are directly reacted with diisocyanates to obtain branched polyurethanes, although it is difficult to control the reactivity. However, bifunctional castor oil can be polymerised with diisocyanates in the presence of suitable chain extenders and catalysts to produce polyurethanes in a more controlled manner (Fig. 6.4). A castor oil polyol-based polyurethane network can also be prepared from epoxy terminated polyurethane pre-polymer with 1,6-hexamethylene diamine. Epoxy terminated pre-polymer is obtained by the reaction of glycidol and isocyanate terminated polyurethane pre-polymer of castor oil polyol, poly(ethylene glycol) (PEG) and 1,6-hexamethylene diisocyanate. ... 

If a branched polyol, usually either castor oil or a simple polyester, is heated with an isocyanate but without chain extenders soft and weak rubbery products are obtained with very low resilience. These materials are useful for encapsulation of electronic components and for printer rollers. 

Polyurethane foams may be rigid, semi-rigid or flexible. They may be made from polyesters, polyethers or natural polyols such as castor oil (which contains approximately three hydroxyl groups in each molecule). Three general processes are available known as one-shot, prepolymer or quasi-prepolymer processes. These variations lead to 27 basic types of product or process, all of which have been used commercially. This section deals only with flexible foams (which are made only from polyesters and polyethers). Since prepolymers and... 

Products intermediate to the flexible and rigid foams may be obtained from castor oil (a trihydroxyl molecule), synthetic triols of moderate molecular weight and polyesters with a moderate amount of trifunctional hydroxyl compound in the strueture. Current practice, however, is to use tipped polyols of the type used for flexible foams with MDI. Semi-rigid foams are used for such purposes as crash pads, car steering wheels and packaging equipment. 

Numerous other polyols are commercially available, some from renewable resources. Urethanes based on castor oil have been used for many years as encapsulants for electronic components, due to their hydrophobic nature [29J. 

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. 

One of the more advanced technical offerings from castor oil is a line of polyester diols, triols, and higher functional polyols derived from 100% castor oil as products for the preparation of polyurethane prepolymers and elastomers [68]. The Polycin line of polyols are prepared by transesterification of ricinoleic acid and derivatives. The producers (Vertellus) offer diol and triol products, as well as a recently developed series of diol and triol glyceryl ricinoleate esters that are stated to be prepared from 100% castor oil, making them fully renewable in content. The products are recommended for coatings, sealants, and adhesive applications. 

Helling R (2006) Life cycle analysis of polyols from soy oil or castor oil. In Proceedings AlChE 2006, Topical Session 4 Sustainable Biorefineries, 16 November 2006, San Francisco. AlChE, New York... 

Castor polyols Castor oil (CO) is mainly available in India and Brazil although the USA also produces a considerable quantity. Castor oil is produced either by expression or by solvent extraction from its seeds, also known as castor beans . It is a viscous liquid with a characteristic unpleasant taste and can be made odorless and tasteless by neutralization and subsequent deodorization. The grade of castor oil is decided by its... 

ISRO polyol is considered to be a substitute for HTPB binder and propellants based on it are used in sounding rockets (RH-300). Such propellants are also considered as candidate propellants [94] for the booster stages of Polar Satellite Launch Vehicle (PSLV). The easy availability of castor oil coupled with its low cost makes ISRO polyol more attractive compared with current binders [95] like PBAN, CTPB and HTPB. 

While the use of these polyethers is widespread, the goal of discussion is to create a specialty chemical. Propylene- and ethylene-based polyols are produced for physical reasons and will serve as the backbone. Researchers should note, however, that the scope of polyethers and polyesters is much broader when they are willing to sacrifice some physical strength to gain a chemical advantage. To illustrate, we cite a particularly interesting example. Castor oil was a conunon polyol for the production of polyurethanes. It was replaced by less expensive and more predictable polyols in commercial production. Readers should be aware that mixed polyols can be used to advantage. 

Other Polyols, Hydroxyl-containing vegetable oils such as castor oil were used for producing semi-flexible foams in the initial stage of the urethane foam industry, but they have not been used much in recent years. 

Renewable materials can be used in the preparation of polyurethanes. Glycosides of polytetrahydrofuran have been used with diisocyanates.164 Castor oil (which contains about 2.7 OH per molecule) has also been used.165 Polyols derived from epoxidized soybean oil have been used to make polyurethanes.166 Lactic acid oligomers can be used.167 Wheat Board is made from wheat straw and isocyanates.168 It is said to be lighter and as strong as and more resistant to moisture than conventional particle board. No formaldehyde is needed for this building material. 

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