Tris -ethyl isocyanate

Bisphenol A (chemically similar to MDA but having -OH groups rather than amine groups) was identified in the water and 3% acetic extracts from Sample 2. Bisphenol A was not detected in the extracts from Sample 1. Infrared transmission spectra recorded through Samples 1 and 2 showed that the MDl isocyanate was slower to react in Sample 2 and so the bisphenol A could possibly relate to the laminating adhesive. As a result, LC-MS tests were undertaken later in the research, on extracts from Sample 3 (laminated with the same adhesive) specifically looking for bisphenol A - none was detected. Tri-ethyl phosphate, thought to be used as a cure catalyst, was identified in the extracts from both Sample 1 and Sample 2. 

Various polyesters derived from phosphorous or phosphoric acids were prepared. Efiicient polyphosphites were synthesised in the early 196(. Polyphosphite prepared from 152 and 4,4 -isopropylidenebis(cyclohexanol) was tested as a thermal stabilizer for PC [199] or as secondary AO for radiation sterilized EPM [200]. Built-in phosphites obtained by transesterification of triallcylphosphite with 4,4 -isopro-pylidenebisphenol or 4,4 -thiobisphenol possess antioxidant properties in polyolefins. Stabilizer containing phosphite moiety 153 was prepared from tris(2-hydroxy-ethyl)isocyanate, decyl alcohol and triphenylphosphite [201]. Various phosphites were derived firom polynuclear phenols or dihydric phenols. For example, a polycondensate prepared by reaction of phosphorus trichloride with 2,5-di-rert-butylhydroquinone was tested as heat and light stabilizer for PP [202], A linear polyester with a built-in phenolic moiety was synthesised from (2,6-di-tm-butyl-4-methylphenyl)bis(6-hydroxyhexyl)phosphite and dimethyl terephthalate [203]. 

Very recently Papa and Critchfield El9 7 described the prepara tion of foams based on a resole resin containing a high ortho-methylol content and a blend of quasi prepolymer of tolylene diiso cyanate, a phosphorus-containing polyol and polymeric isocyanate containing a minor portion of tris-(2-chloro-ethyl) phosphate. 

AETHYLALKOHOL (German) (64-17-5) Forms explosive mixture with air [flash point 55°F/13°C 68°F/20°C (80%) 72°F/22°C (60%) 79°F/26°C (40%)]. Reacts, possibly violently, with strong oxidizers, bases, acetic anhydride, acetyl bromide, acetyl chloride, aliphatic amines, bromine pentafluoride, calcium oxide, cesium oxide, chloryl perchlorate, disulfuryl difluoride, ethylene glycol methyl ether, iodine heptafluoride, isocyanates, nitrosyl perchlorate, perchlorates, platinum, potassium-tert-butoxide, potassium, potassium oxide, potassium peroxide, phosphorus(III) oxide, silver nitrate, silver oxide, sulfuric acid, oleum, sodium, sodium hydrazide. sodium peroxide, sulfinyl cyanamide, tetrachlorosilane, -tri-azine-2,4,6-triol, triethoxydialuminum tribromide, triethylaluminum, uranium fluoride, xenon tetrafluoride. Mixture with mercury nitrate(II) forms explosive mercury fulminate. Forms explosive complexes with perchlorates, magnesium perchlorate (forms ethyl perchlorate), silver perchlorate. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

A solution of a proprietary isocyanate compound (1 wt.% in ethyl acetate) was provided by an industrial partner. The mid-IR spectrum was recorded at a resolution of 4 cm for a scan time of 30 s, then the solution (25 ml) was treated with an excess amount of tri- -butylamine (5 ml, 99% pure from Alfa Aesar) and spectra were recorded every 60 s for a total of 80 minutes. The reaction was carried out at room temperature. 

Blocked isocyanates permit making coatings that are stable at ambient temperature when baked, the monofunctional blocking agent is volatilized and the coreactant is cross-linked. An extensive review of blocked isocyanates, their reactions, and uses is available (127). The blocking agents most widely used are phenols, oximes, alcohols, e-caprolactam (hexahydro-2ff-azepin-2-one) [105-60-2], 3,5-dimethylpyrazole, 1,2,4-triazole, and diethyl malonate (propanedioic acid diethyl ester) [105-53-3]. A variety of catalysts are used DBTDL is most widely used but many other catalysts have also been used. Bismuth tris(2-ethyl hexanoate) has been particularly recommended (128). In electrodeposition primers, DBTDL has insufficient hydrolytic stability, and tributyltin oxide is an example of an alternate catalyst (129). Cyclic amidines, such as l,5-diazabicyclo[4.3.0]non-5-ene, are reported to be superior catalysts for use with uretdione cross-linkers in powder coatings (130). 

A phosphorus-containing isocyanate can also be employed, although P(=0)N=C=0 types, in general, are expensive to synthesize and, moreover, give hydrolytically unstable urethanes. The only phosphorus-containing isocyanate currently on the market is Bayer s Desmodur RFE, a solution in ethyl acetate of tris(p-isocyanatophenyl) thionophosphate (206). 

One can easily observe the similarity between coatings and adhesives. Poly isocyanates used for adhesives should have high molecular weight and thus, low vapor pressure at the reaction temperature. Adducts such as Desmodur L, or crude MDI are often used, as are triisocyanates such as triphenyl methane-4,4, 4"-triisocyanate (a) or tris(p-isocyanatophenyl) ester of thiophosphoric acid (b) dissolved in methylene chloride or ethyl acetate ... 

Crosslinkers. Polyisocyanates with functionality greater than two (such as p, p", p " -triisocyanate triphenylmethane, thiophosphoric acid tris (p-isocyanatephenyl) ester) can be added to improve specific adhesion and heat resistance of the polyurethane adhesives (especially those with slower crystallization rate). Most of them have 20-30 wt% solids, 5.4-7 wt% free NCO and the most common solvent is ethyl acetate. 5-10% polyisocyanate is generally added in the adhesive solution just before appHcation on the substrate, and it acts as cross-linking agent. Since all isocyanates react with the residual hydroxyl groups on the polyurethane, in solution they all yield adhesive systems with a limited pot life (1-2 h to several days). Addition of polyisocyanate improves the spotting tack and heat activation of the freshly dried adhesive films, but after several days they lose their capacity to be reactivated. 

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