| 摘要 |
<p>The invention discloses a polyvinyl alcohol obtained through hydrolysis of a polyvinyl ester that contains silyl group-having monomer units. The polyvinyl alcohol satisfies the following formulae (I) and (II) and the pH of aqueous 4 % solution thereof falls between 4 and 8: <DF NUM="(I)">20 < P x S < 370 </DF> wherein P indicates the viscosity-average degree of polymerization of the polyvinyl alcohol, and S indicates the content (mol%) of the silyl group-having monomer units in the polyvinyl alcohol, <DF NUM="(II)">0.1/100≤(A - B) / (B)≤50/100 </DF> wherein A indicates the silicon atom content (unit: ppm) of the polyvinyl alcohol, B indicates the silicon atom content (unit: ppm) of the polyvinyl alcohol that has been washed with sodium hydroxide-containing methanol and then washed through Soxhlet extraction with methanol. <??>The polyvinyl alcohol is characterized in that it may be readily dissolved in water to form an aqueous solution thereof even though an alkali such as sodium hydroxide or an acid is not added thereto; its aqueous solution has good viscosity stability; its binding force with inorganic substances is high; and a film formed of its mixture with an inorganic substance is excellent in resistance to water. The polyvinyl alcohol is favorable for coating agents for inkjet recording materials and thermal recording materials.</p> |
