摘要 |
<p>A two step process for preparation of 'high ortho' novolac resins. A first step involving reaction of phenolic component with formaldehyde carried out at room temperature, which ensures that all the formaldehyde used in the reaction is in liquid state, which almost completely reacts with phenolic compound, leaving no unreacted formaldehyde as effluents. The process uses CNSL or CNSL based phosphorylated prepolymer, or CNSL based monomeric Cardanol or hydrogenated Cardanol or vicinally hydroxylated Cardanolwith formaldehyde and other phenolic compounds like m-cresol or p-cresol or o-cresol or 3.5-dimethylphenol or p-chlorophenol or resorcinol or t-butylphenol. the positive and negative photoresists are made by mixing these polymers with appropriate photoactive components. For preparation of e-beam photoresist, these novolac resins are fist derivatised by t-BOC and then mixed with photoacid generator.</p> |