| 摘要 |
<p>A method for producing non-flammable laminated plastics wherein a cellulose-containing material is impregnated with a phenolic-resin solution containing plasticizers of phosphoricacid esters with aliphatic alcohols or phenols and, optionally, flame-proofing agents, the alcohol component of the phosphoricacid ester being either a monovalent alcohol having 4 to 18 carbon atoms, a polyvalent alcohol having 4 to 18 carbon atoms or a phenol selected from phenol, methyl phenols and polyvalent phenols, the impregnated material is dried and layers of the dried impregnated material are placed on top of the other and subjected to heat and pressure treatment at 70 to 180 kp/cm2. The method is characterized in that the impregnating solution is a phenol-resol resin solution containing (a) 50 to 80% by weight of an ammonia-alkaline condensed phenol-resol resin having a viscosity of from 500 to 5000 cP, a solids content of between 65 and 80% by weight and a molecular-weight distribution, expressed in % by area and determined by gel chromatography, of 20 to 26% of dimers, 6 to 12% of trimers and tetramers, 24 to 36% of pentamers and oligomers, and (b) 1 to 15% by weight of hexamethylene tetramine. The laminated plastics obtained have a high degree of non-flammability and a short after-burn. One particular advantage of the method according to the invention resides in that a considerably shorter age-hardening period is required, about 10 to 30% shorter as compared with similar production conditions for hitherto-known laminated papers.</p> |
