| 摘要 |
The floor covering of the present invention has a wear layer and/or seam coater which is a high Tg urethane composition. While most floor covering urethanes have a Tg of from 18 DEG C. to 23 DEG C., the Tg of the present urethane is above about 40 DEG C., and preferably from about 48 DEG C. to about 55 DEG C. The Tg of the prior art has been increased by altering the composition of the aromatic acid based polyester polyols used in the prior art moisture curable prepolymers. By raising the precursor polyol to dicarboxylic acid ratio, the polyester polyols produced have lower equivalent weights. This alone results in a polyurethane-urea of higher Tg at a given alicyclic diisocyanate to polyester equivalent ratio. However, increases in the Tg may also be obtained by replacing some or all of long chain flexible polyol precursors (e.g. triethylene glycol) with shorter and/or less flexible polyol precursors. The high Tg improves stain resistance. The moisture cure of the present urethane composition can be carried out at ambient conditions, permitting its use as a seam coater or sealer as well as a wear layer. |
