ε-Caprolactam was anionically fast-polymerized in a metal mold and the parameters associated with the casting reaction such as heating cycle, catalyst- and initiator-concentration etc. were investigated. ε-Caprolactam dried by vacuum-distilling over phosphorous pentoxide to a proper temperature and was activated by the addition of certain amount of catalyst and initiator. The casting mix was then introduced into a preheated mold with the least contact with air, and the mold was placed in a heating oven. After certain time period the mold was removed from the oven and cooled. Among the catalyst bases investigated sodium hydride was the most active and convenient to use. Hexanediisocyanate gave the best results as an initiator. The product thus polymerized contained 2∼3 % of equilibrium monomer concentration and the molecular weight was in the range of 500,000. Density measurement and DSC analysis indicated that crystallinity was high (40%). Various strength values were higher than those of common molded nylon 6 products. Tensile strength was in the range of 900 kg/cm² and modulus of elasticity was in the range of 40,000 kg/cm².

ε-Caprolactam에서 수분을 완전히 제거한 후 촉매로서 sodium hydride, 중합개시제로서 hexanediisocyanate를 사용하여 그들의 농도와 반응온도를 변화시키면서 나일론 6의 monomer casting에 대한 최적 조건을 구하였다. 합성방법은 음이온 중합에 의한 bulk polymerization으로써 먼저 ε-caprolactam을 감압 증류하여 수분을 제거시킨 후 130∼135℃로 가열하여 sodium hydride(0.35 mole %), hexanediisocyanate(0.35 mole %)를 넣어 활성화시킨 다음 180℃로 예열된 금형에 넣고 190℃까지 가열하여 12∼15분 간 반응시켰다. 다음 온도를 내려 180℃에서 20∼30분간 유지한 후 금형을 상온까지 천천히 식혀 monomer cast nylon을 얻었다. 이렇게하여 생성된 성형체는 monomer의 함량이 2∼3%정도이기 때문에 추출할 필요가 없었고 분자량은 500,000 정도였다. 밀도 측정과 DSC 분석에 의하면 결정성이 높았으며 (40%), 융점은 220℃ 였다. 인장강도와 탄성계수를 측정한 결과 사출 성형제품 보다 각각 20%, 75%정도가 증가하였다.