Hexamethylene glycol polyester

The telomeric aliphatic polyesters were produced by polycondensation based on adipic acid and hexamethylene glycol in various stoichiometric amounts to generate polyesters of different end group functionality. The polyesters of different molar mass and corresponding reference samples were synthesized at the Center for Macromolecular Chemistry, Berlin, Germany. These types of polyesters are widely used as lacquers and precursors for the production of several important polyurethanes. 

PVC can be blended with numerous other polymers to give it better processability and impact resistance. For the manufacture of food contact materials the following polymerizates and/or polymer mixtures from polymers manufactured from the above mentioned starting materials can be used Chlorinated polyolefins blends of styrene and graft copolymers and mixtures of polystyrene with polymerisate blends butadiene-acrylonitrile-copolymer blends (hard rubber) blends of ethylene and propylene, butylene, vinyl ester, and unsaturated aliphatic acids as well as salts and esters plasticizerfrec blends of methacrylic acid esters and acrylic acid esters with monofunctional saturated alcohols (Ci-C18) as well as blends of the esters of methacrylic acid butadiene and styrene as well as polymer blends of acrylic acid butyl ester and vinylpyrrolidone polyurethane manufactured from 1,6-hexamethylene diisocyanate, 1.4-butandiol and aliphatic polyesters from adipic acid and glycols. 

The saturated polyesters that find conunercial applications are mostly linear, except for some specially prepared branched polymers used in the preparation of polyurethanes. The linear polyesters became commercially important materials early in this century and still find many uses in industry. The earliest studies reported condensations of ethylene, trimethylene, hexamethylene, and de-camethylene glycols with malonic, succinic, adipic, sebacic, and orthophthalic acids. Later studies showed that such condensations yield high molecular weight compounds. Nevertheless, these polyesters exhibit poor hydrolytic stability and are generally low-melting. Subsequently, however, it was found that aromatic dicarboxylic acids yield polymers with high melting points, and poly(ethylene terephthalate), which melts at 265 C, is now an important commercial material. 

Chemistry Polyurethane is produced by the reaction of a polyol with an diisocyanate (or in some instances a polyisocyanate) in the presence of catalysts. The polyols of choice are poly(propylene glycol), block copolymers of ethylene oxide (10-15%) with propylene oxide, or the newer polymer polyols (based on polymers such as polystyrene or styrene-acrylonitrile copolymer). Polyester diols such as polycaprolactone diol can be used in place of the polyether polyol in this reaction. The isocyanate of choice is a mixture of the 2,4 and 2,6 isomers of tolylene di-isocyanate in the ratio of 80 20, generally referred to as 80 20TDI. Other isocyanates such as diphenylmethane di-isocyanate (MDI), hexamethylene di-isocyanate (HMDI), and isophorone di-isocyanate (IPDI) are also used. A tin-based or amine catalyst is used to promote the reaction. Given the wide choice of reactants available, the reaction can yield foams with a range of different mechanical and thermal characteristics. 

Common SS include polyethers, polyesters and polyalkyl glycols with glass transition temperatures in the range of -70°to -30°C. Commonly used macrodiols in the PUs synthesis are polyalkyl-diols, such as polyisobutylene diol [70], polybutadiene (PBU) [20, 71], or oligo-butadiene diols [72] as well as hydrogenated polybutadiene diol [20] polyether diols polytetrahydrofuran (PTHF or PTMO) [50-52], polyethylene glycol (PEG) or (PEO) [73], polypropyleneoxide (PPO) [73] or mixed blocks of them PEO-PPO-PEO [74] and PPO-THF [54] polyester diols poly(ethylene adipate) (PEA) [4,20], poly(butylene adipate) (PBA) [20, 73], and latterly polycaprolactone diol (PCL or PCD) [75], polyalkylcarbonate polyol [20] or mixed blocks of them, for example poly(carbonate-co-ester)diol [76], poly(hexamethylene-carbonate)diol [77], as well as poly(hexamethylene-carbonate-co-caprolactone)diol [78] and a mixed block copolymer of polyether and polyester blocks PCL-b-PTHF-b-PCL [79]. Examples schemes of macrodiols are shown in Eig. 1.9. 

The most important polyurethane adhesive components are toluene diisocyanate (TDI), 4,4 -diphenylmethane diisocyanate (MDI), p-anisidine diisocyanate (DADI), hexamethylene diisocyanate (HDI) and triphenyl-methane triisocyanate (Desmodur R) (see Fig. 8.1), together with various polyester and polyether glycols. (See Fig. 1.9 of Chapter 1 for the formulae of TDI, MDI and HDI, and Fig. 8.5 for the formula of DADI.) Toluidine diisocyanate (TODI) (Fig. 8.1) is also used. 

An isocyanate-terminated, viscous linear prepolymer is prepared from 2 mol of hexamethylene diisocyanate and 1 mol of hydroxyl-terminated linear polyester prepared from diethylene glycol and adipic acid. Two... 

Ex. 1. Windemuth teaches the practice of (a), a one part system. An isocyanate-terminated, viscous (in the melt), linear prepolymer is prepared from 2 moles of hexamethylene diisocyanate (II) and 1 mole of hydroxyl-terminated, linear polyester prepared from diethylene glycol and adipic acid. Two percent of hexa-hydrodimethyl aniline (a basic catalyst) is added to this prepolymer dissolved in dry benzene. The solution is applied to adherend members (e.g., the two ends of a leather drive belt) and dried. Subsequent brief exposure of the coated parts to moist air, followed by their contact under light pressure, results in a tough, flexible, rubbery bond in 2 to 3 hr. 

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