Dibutyl tin dilaurate

In recent years there has been some substitution of TDI by MDI derivatives. One-shot polyether processes became feasible with the advent of sufficiently powerful catalysts. For many years tertiary amines had been used with both polyesters and the newer polyethers. Examples included alkyl morpholines and triethylamine. Catalysts such as triethylenediamine ( Dabco ) and 4-dimethyla-minopyridine were rather more powerful but not satisfactory on their own. In the late 1950s organo-tin catalysts such as dibutyl tin dilaurate and stannous octoate were found to be powerful catalysts for the chain extension reactions. It was found that by use of varying combinations of a tin catayst with a tertiary amine... 

A typical condensation system involves the reaction of a silanol-terminated polydimethylsiloxane with a multi-functional organosilicon cross-linking agent such as Si(RO)4 Figure 29.8). Pot life will vary from a few minutes to several hours, depending on the catalysts used and the ambient conditions. Typical catalysts include tin octoate and dibutyl tin dilaurate. 

Catalysts such as dibutyl tin dilaurate or tertiary amines are added to promote the urethane reaction and/or subsequent moisture cure. Dimorpholine diethyl ether is particularly effective at promoting moisture cure without promoting allophanate side reactions at the application temperature (which leads to instability in the hot melt pot) [29]. 

Initiation of stannous octoate-catalyzed copolymerization of e-caprolactone with glycerol was used to prepare a series of trifunctional hydroxy-end blocked oligomers, which were then treated with hexane-1,6-diisocyanate to form elastomeric polyesterurethanes with different crosslink densities (49). Initiation of e-caprolactone polymerization with a hydroxypropyl-terminated polydimethylsiloxane in the presence of dibutyl tin dilaurate has been used to prepare a polyester-siloxane block copolymer (Fig. 4) (50). 

The foams can be obtained by the action of a diiscyanate on a polyol and water. The reaction with water forms carbon dioxide and the reaction with polyol forms a urethane polymer. Catalysts play a crucial role in the process. Tin octeate and dibutyl tin dilaurate are preferred catalysts along with tertiary amines. 

Half-blocked Dllsocyanates. The half-blocked diisocyanates were prepared using conventional methods (2) by adding dropwlse, over a period of one hour, 1 mole of alcohol to 1 mole of diisocyanate and 100 mg dibutyl tin dilaurate in methyl amyl ketone under an inert atmosphere. After the addition of the alcohol, the reaction was heated at 60-80°C for 2 hours. For half-blocked diisocyanates prepared from tertiary alcohols, the heating period was replaced with room temperature stirring for 24-36 hours to prevent undesirable side reactions. 

We have prepared and characterized three linear isosorbide containing polyurethanes with toluene diisocyanate (TDI), 4,4 -diphenylmethane diisocyanate (MDI), and 1,6-hexamethylene diisocyanate (HMDI) P(I-TDI), P(I-MDI), and P(I-HMDI). These polyurethanes have been synthesized as described in the experimental section by solution polymerization of isosorbide with the corresponding diisocyanate in dimethylacetamide using dibutyl-tin dilaurate as the catalyst at 75 C for 24 hours. All polymers have been isolated in quantitative yield by precipitation in methanol or water (5). 

Methods. Reaction with IEM Reactions with IEM were performed in methylene chloride using dibutyl tin dilaurate (ca. 1 wt.%) as catalyst. The reaction mixture with model compound or HBL was reacted at 40°C under dry nitrogen. The reaction product was obtained by precipitation with n-hexane. Detailed experimental and analytical results are given elsewhere (15). 

Health and Safety Reporting Rule Dibutyl tin dilaurate Dibutyl tin bis(lauryl mercaptide) Dibutyl tin bis(isooctylmaleate) Monobutyl in tris(isooctyl) mercaptoacetate... 

Preliminary Assessment Information Reporting Rule Dibutyl tin dilaurate... 

Tin-based salts such as stannous oleate or a dibutyl tin salt (Dibutyl tin dilaurate DBTL) will activate the OH-NCO reactions. This group speeds up the overall reaction rate as well. They also even out the reactivities of low-and high-molecular-weight polyols. 

Tin compounds such as dibutyl tin dilaurate at -30 0 ppm are found in polyester polyols. Phosphoric acid can be found in polyols for control of pH and side reactions. 

Dibutyl tin dilaurate (DBTL, Aldrich, 95%) and phenyl isocyanate (PhNCO, Acros, 99%) were used as received. 

Both one-component and two-component silicone sealants contain polydimethyl siloxane as the base polymer along with fillers such as calcium carbonate and/or fumed silica fillers, plasticisers (silicone oil) and a variety of cross-linking agents and adhesion promoters. Two-component sealants utilise a catalyst such as dibutyl tin dilaurate, alkyl silicate esters and metallic salts (Maslow, 1982). 

The second type of release agent, such as polyethylene waxes, is used if the mold must be stripped away when cold. In this case the foam comes away from the release agent. Mold-release problems can be reduced by adding small amounts of dibutyl tin dilaurate, which promotes curing at the surface of the mold and thus improves mold release (4). 

The catalysts dibutyl tin dilaurate and dioctyl tin dilaurate typically used to prepare resins for epoxy adhesives must be removed on completion of reaction in the case of epoxy adhesives to be used in computer mainframes. The vapour generated through heat releases tin vapour salts which can damage sensitive electronic components. 

Materials. Phenyl isocyanate (Eastman Kodak) and 2-butanol were fractionally distilled under reduced pressure prior to use. Dioxane was purified by first refluxing with sodium metal, then distilling under reduced pressure. Triphenyl phosphine, dibutyl-tin dilaurate (DBTDL) and cobalt acetylacetonates were used as-received from Eastman Kodak and M T companies, respectively. 

As a first observation, the difference in reactivity between the hydroxyl groups of triethanolamine and the hydroxyl groups of liquid polyether is not so high as that between amino groups and hydroxyl groups in reaction with a diisocyanate. In order to accelerate the reaction of diisocyanate with the primary hydroxyl groups of triethanolamine in PIPA production, specific catalysts such as dibutyl tin dilaurate or stannous octoate are used [79-87]. 

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