1 The appearance :black or red brown,smooth and soft surface, without foreign matters ,bubbles and mechanical damahges and with good self-adhesive property at normal temperature.
1 The appearance :black or red brown,smooth and soft surface, without foreign matters ,bubbles and mechanical damahges and with good self-adhesive property at normal temperature.
1外观：黑色或棕红色，表面光滑柔软无杂质，气泡，无机械损伤，常温下有较好的自粘性。