| 摘要 |
<p>A concrete hardening retarder which comprises a polymer (A) having the ability to retard concrete hardening. The polymer (A) comprises structural units derived from an ingredient capable of bringing about a glass transition temperature (Tg) of -5 ~C or lower. The retarder has a surface tension of 45 mN/m or lower. The content of those units is about 10 wt.% or higher based on the whole polymer (A). The polymer (A) has a functional group capable of forming a salt with a metal ion (especially a free acid group or a group capable of generating an acid group through hydrolysis). The polymer (A) may be a vinyl polymer, a polyester (saturated or unsaturated polyester), or a cross-linked or graft polymer obtained from an unsaturated polyester. A sheet or decorative-material pack may be formed from the retarder. Use of the retarder, sheet, pack, or the like is effective in improving stain removability from the surface of the concrete panel having tiles attached thereto beforehand, the suitability of a concrete surface for washing finish, and the state of the finished surface.</p> |
