Verfahren zur Herstellung von Schaumstoffen

摘要

3,4 - Dihydro - 2H - pyran - 2 - methyl -(3,4 - dihydro - 2H - pyran - 2 - carboxylate) of formula is prepared by the self-condensation of acrolein dimer (2-formyl-3,4-dihydro-2H-pyran) in the presence of aluminium isopropoxide. Butanediol - 1,4 - bis - (3,4 - dihydro - 2H-pyran-2-yl) ether is prepared from butanediol-1,4-divinyl ether and acrolein (Example 66). The divinyl ether of polypropylene glycol 425 is prepared by treating the glycol with acetylene at 180-190 DEG C. and 200-250 p.s.i. in the presence of KOH (Example 195). A complex ester is prepared from equimolar quantities of diethylene glycol, trimethylolpropane and maleic anhydride (Example 263). The benzoate of 2-hydroxymethyl-3,4-dihydro-2H-pyran is prepared from benzoyl chloride and the alcohol (Example 264). Specifications 923,403 and 930,635 are referred to. ALSO: Cellular materials are prepared from compositions comprising at least one polymerizable vinyl ether containing at least two vinyl groups per molecule, a foaming agent and an acidic catalyst. The vinyl groups may be substituted and the vinyl ether groups may form part of a ring (e.g. the 3,4-dihydro-2H-pyran ring). The vinyl ether may have one of the generic formulae where n is an integer of at least 2, R1 and R2 are hydrogen or alkyl, R3 is hydrogen, halogen or hydrocarbyl, R4 and R5 are hydrogen or alkyl or together represent alkylene or substituted alkylene forming a cyclic structure with , R6 is hydrogen or alkyl and A is a linking group of valency n. A may contain ether, carboxylic ester or carbamate ester groups. Many suitable vinyl esters are specified, typically 3,4-dihydro - 2H - pyran2 - methyl - (3,4 - dihydro - 2H - pyran - 2 - carboxylate of formula. and phosphate and polycarboxylic esters of 2 - hydroxymethyl - 3,4 - dihydro - 2H - pyran as well as acyclic ethers; in Example 106 there is used a styrene/methacrylate/polyol/3,4-dihydro - 2H - pyran - 2 - methyl - (3,4 - dihydro - 2H - pyran - 2 - carboxylate) resin prepared by first reacting polypropylene glycol 425, styrene and methacrylic acid in the presence of peroxides, reacting the product with butylene oxide after adding (CH3)2NC12H25, and then adding crude 3,4 - dihydro - 2H - pyran - 2 - methyl - (3,4 - dihydro - 2H - pyran - 2 - carboxylate). The foaming compositions may contain additionally at least one compound reactive with the vinyl ether. Such compounds include phenolic compounds, aliphatic mono- and poly-hydric alcoholic compounds, epoxidized materials containing at least one epoxide group, acidic compounds containing at least two carboxylic acid groups or corresponding anhydrides, amido compounds containing at least two amido groups, carbamate groups, polymerizable alpha, betamonoethylenically unsaturated compounds, alkyl and acyl cellulose derivatives, and various specified combinations of such compounds; very many suitable compounds are specified including polymeric substances. Volatile foaming agents are preferred, e.g. trichloromonofluoromethane and other halocarbons. Strong acid catalysts are preferred; many are specified including mineral acids, p-toluenesulphonic acid, carboxylic acids and numerous Lewis acids. The foaming compositions may also include materials copolymerizable with the other ingredients, e.g. cyclic anhydrides, surfactants such as siloxane oxyalkylene copolymers and other conventional additives including flame retardants such as trichloroethyl phosphate, 2,2 - bis - (31,51 - dibromo - 41 - hydroxyphenyl) propane, chlorendic acid and polyvinyl chloride with or without antimony oxide. Carbamate group-containing prepolymers containing free isocyanate and free hydroxyl groups respectively are prepared in Examples 239 and 247 from 1,5-pentanediol and toluene 2,4-diisocyanate. Specifications 923,403 and 930,635 are referred to.