In the manufacturing process of ceramics, bisque firing is performed to make the green body strong. In case the green body has sufficient strength, it could be possible to save energy by eliminating the bisque firing. Aiming at further reduction of CO2 emission for low-temperature sintering porcelain, carboxymethyl cellulose (CMC) was added to reinforce the green body. The amount added, viscosity and degree of substitution (DS) of CMC on the strength of the green body were investigated. Increasing the amount of CMC, the strength of the green body was gradually increased, reaching double to triple value by adding 0.5 % of CMC. The addition of CMC reduced water absorption of the green body, meaning that it increased the bulk density. DIC (Digital Image Correlation) method proofed that the strains inside the green body was suppressed by adding CMC, suggesting that CMC played a role of binder between low-temperature sintering porcelain powders to lead to improve the strength. Low-viscosity CMCs are easy to handle, however, higher-viscosity CMCs demonstrated slightly higher strength. Using CMC with lower DS tended to decrease the strength probably due to lower miscibility to water.
