| 摘要 |
PURPOSE:To provide a paste for a protective sheet, which can prevent a folded area of the contact surface of a bar heater from being roughened and cracked, by incorporating a specified organoboron compd. in an aq. soln. of a partially saponified polyvinyl acetate. CONSTITUTION:0.01-20wt% (based on the weight of solid in an aq. soln. of a partially saponified polyvinyl acetate) organoboron compd. of the formula is incorporated in an aq. soln. contg. 3-15wt% partially saponified polyvinyl acetate, pref. one having a degree of saponification of 71.0% or above. Optionally, a plasticizer, a moisture absorbent, a preservative, a thickener an anti-foaming agent, etc. may be added to the above paste compsn. It is desirable to adjust the viscosity of the paste to 200-10,000cp from the viewpoint of a coating operation. The paste is applied in a coating quantity of 0.4-10g/m<2>, pref. 0.6-2g/m<2>.
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