Butanediol polyurethane

Molded urethanes are used in items such as bumpers, steering wheels, instrument panels, and body panels. Elastomers from polyurethanes are characterized by toughness and resistance to oils, oxidation, and abrasion. They are produced using short-chain polyols such as polytetram-ethylene glycol from 1,4-butanediol. Polyurethanes are also used to produce fibers. Spandex (trade name) is a copolymer of polyurethane (85%) and polyesters. 

Christenson C P, Harthcock M A, Meadows M D, Spell H L, Howard W L, Creswick M W, Guerra R E and Turner R B (1986) Model MDI/Butanediol polyurethanes Moleculai structure, morphology, physical and mechanical properties, J Polym Sci Part B Polym Phys 24 1401-1439. 

HOCH2CH2CH2CH2OH. B.p. 228"C. Prepared ethyne plus methanal, hydrogenated to butanediol. Used in production of y-buty-rolactone and 2-pyrrolidone. Widely used in polyurethane products, butylenes See butenes. 

Heating butanediol with acetylene in the presence of an acidic mercuric salt gives the cycHc acetal expected from butanediol and acetaldehyde (128). A commercially important reaction is with diisocyanates to form polyurethanes (129) (see Urethane POLYMERS). 

Uses. The largest uses of butanediol are internal consumption in manufacture of tetrahydrofuran and butyrolactone (145). The largest merchant uses are for poly(butylene terephthalate) resins (see Polyesters,thermoplastic) and in polyurethanes, both as a chain extender and as an ingredient in a hydroxyl-terminated polyester used as a macroglycol. Butanediol is also used as a solvent, as a monomer for vadous condensation polymers, and as an intermediate in the manufacture of other chemicals. 

Butanediol. 1,4-Butanediol [110-63-4] made from formaldehyde and acetylene, is a significant market for formaldehyde representing 11% of its demand (115). It is used to produce tetrahydrofuran (THF), which is used for polyurethane elastomers y-butyrolactone, which is used to make various pyrroHdinone derivatives poly(butylene terephthalate) (PBT), which is an engineering plastic and polyurethanes. Formaldehyde growth in the acetylenic chemicals market is threatened by alternative processes to produce 1,4-butanediol not requiring formaldehyde as a raw material (140) (see Acetylene-derived chemicals). 

Much more important is the hydrogenation product of butynediol, 1,4-butanediol [110-63-4]. The intermediate 2-butene-l,4-diol is also commercially available but has found few uses. 1,4-Butanediol, however, is used widely in polyurethanes and is of increasing interest for the preparation of thermoplastic polyesters, especially the terephthalate. Butanediol is also used as the starting material for a further series of chemicals including tetrahydrofuran, y-butyrolactone, 2-pyrrohdinone, A/-methylpyrrohdinone, and A/-vinylpyrrohdinone (see Acetylene-DERIVED chemicals). The 1,4-butanediol market essentially represents the only growing demand for acetylene as a feedstock. This demand is reported (34) as growing from 54,000 metric tons of acetylene in 1989 to a projected level of 88,000 metric tons in 1994. 

Butanediol [110-63-4] (BDO) goes primarily into tetrahydrofuran [109-99-9] (THE) for production of polytetramethylene ether glycol (PTMEG), used ia the manufacture of polyurethane fibers, eg, Du Font s Spandex. THE is also used as a solvent for PVC and ia the production of pharmaceuticals (qv). Lesser amounts of BDO are employed ia the production of polybutylene terephthalate resias and y-butyrolactone. 

Polyester and polyether diols are used with MDI in the manufacture of thermoplastic polyurethane elastomers (TPU). The polyester diols are obtained from adipic acid and diols, such as ethylene glycol, 1,4-butanediol, or 1,6-hexanediol. The preferred molecular weights are 1,000 to 2,000, and low acid numbers are essential to ensure optimal hydrolytic stabihty. Also, caprolactone-derived diols and polycarbonate diols are used. Polyether diols are... 

Polyurethane engineering thermoplastics are also manufactured from MDI and short-chain glycols (49). These polymers were introduced by Upjohn/Dow under the trade name Isoplast. The glycols used are 1,6-hexanediol and cyclohexanedimethanol. 1,4-Butanediol is too volatile at the high processing temperatures used in the reaction extmsion process. Blends of engineering thermoplastics with TPU are also finding uses in many appHcations... 

By the same reaction polyhydroxy materials will react with polyisocyanates to yield polyurethanes. For example, the reaction between 1,4-butanediol and hexamethylenedi-isocyanate is shown below ... 

A new ionic polymeric polycarbamate was synthesized after steps of polyurethane chemistry using 3-iso-cyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate, 2,5-dimethyl-2,5-dihydroperoxyhexane, 1,6-butanediol, 2,4-tolylenediisocyanate, and N,N -bis(j3-Hydroxy-ethyOpiperazine [27]. Modification of the nitrogen of the piperazine ring into quaternary ammonium salt by treatment with methyliodide gave the MPI high electroconductivity. 

Polyurethane fibres (Perlon U) were prepared by reacting hexamethylene disocyanate with 1,4 butanediol in 1942. Because they were difficult to dye and had harsh feel so went out of the market. But these resins are used for small mechanical components like gears and bearings because of dimensional stability and retention of electrical resistance in humid conditions. 

In order to demonstrate the use of laser flash photolysis in elucidation of the MDI based polyurethane photolysis mechanism, three polyurethanes, two aryl biscarbamate models, an aryl monocarbamate model, and an aromatic amine were selected. Two of the polyurethanes are based on MDI while the third is based on TDI (mixture of 2,4 and 2,6 isomers in 80/20 ratio). The MDI based polyurethanes all have the same basic carbamate repeat unit. The MDI elastomer (MDI-PUE) is soluble in tetrahydrofuran (THF). The simple polyurethane (MDI-PU) based on MDI and 1,4-butanediol is used in the tert-butoxy abstraction reactions since it does not contain a polyether backbone. (See page 47 for structures of polymers and models.)... 

The most recent entrant-to the. club of commodity chemicals is 1,4-butanediol (BDO), a petrochemical used in some of the more specialized applications such as chemical intermediates for the production of tetrahydro-furane and gama-butyrolactone, polybutylene terephthalate, and the more familiar polyurethanes. Traditionally, the Reppe process was the primary route to BDO, based bn acetylene and formaldehyde feeds. More recently, the share of BDO from butane and propylene oxide based production has grown rapidly. 

Several polymer-related uses of brassylic acid (BA) have been investigated. For example, a BA/l,3-butanediol/lauric acid oligomer is an effective plasticizer for poljrvinyl chloride,[6] BA/ethylene glycol and BA/propylene glycol polymers function as polyester based polyurethane elastomers,[7] and BA has been patented as a cross-linker for glycidyl methacrylate copolymer powder coatings.[8] However, the most detailed studies have involved polyamides selected data from these studies are summarized in Table I. 

Preparation of a Linear Polyurethane from 1,4-Butanediol and Hexamethylene Diisocyanate in Solution... 

Polyurethanes (PUs) are produced by the reaction of a diisocyanate and a diol or higher polyol. As in the case of nylons and polyesters, the aliphatic PUs and those with many methylene groups between functional groups can be more flexible than aromatic PUs. A typical polyurethane is synthesized using the reactants 1,4-butanediol and hexamethylene diisocyanate as shown below ... 

Cooper et al. [21, 22] reported in detail the results of their laborious work on the adsorption of four proteins human serum albumin (HSA), fibrinogen (FGN), fibronectin (FN), and vitronectin (VN), on five biomaterials polyethylene (PE), silicone rubber (SR), Teflon-FEP (FEP), poly(tetramethylene oxide)-poly-urethane (PTMO-PU), and polyethylene oxide)-polyurethane(PEO-PU). Hard segments of these polyurethanes are composed of a methylene-bis(p-phenylisocyanate) (MDI) chain extended wih 1,4-butanediol. 

Polyurethane energetic block copolymers, (VIII), consisting of toluene diisocyanate, 1,4-butanediol, and dihydroxyl poly(3-azidomethyl-3-methylox-etane) were prepared by Sanderson et al. (3) and used as binders in high-energy compositions, especially rocket propellants. Poly(glycidyl nitrate) urethanes were previously prepared by the authors and are discussed (4). 

Diacetoxy-2-butene. Mitsubishi commercialized a new proces, the acetoxy-lation of 1,3-butadiene, as an alternative to the Reppe (acetylene-formaldehyde) process for the production of l,4-diacetoxy-2-butene. l,4-Diacetoxy-2-butene is tranformed to 1,4-butanediol used in polymer manufacture (polyesters, polyurethanes). Additionally, 1,4-butanediol is converted to tetrahydrofuran, which is an important solvent and also used in polymer synthesis. 

In a recent patent, Reuter (110) describes a polyurethane prepared from PTHF (mol. wt. 1000 to 3000), 1,4-butanediol, and OCN(CH2)6CN0. In another case Murbach and Adicoff (67) interrupted the regularity of PTHF by copolymerization with ethylene oxide before chain extension with diphenyl-methane-4,4 -disiocyanate. Dickinson (99) prepared a series of polyurethane elastomers from THF-PO copolymer diols and 2,4-tolylene diisocyanate. He found that the use of copolymers with approximately 75 wt.-% THF led to polyurethanes with very good properties relative to the use of propylene oxide homopolymer. 

Butanediol (BDO) goes primarily into tetrahydrofuran (THF) for production of polytetramethylene ether glycol (PTMEG), used in the manufacture of polyurethane fibers. 

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