Before the tacky rubbers, Chinese players use mostly short pimple. Until China lost in the WTTC 1971， where the opponents are using powerful inverted rubbers. Then Chinese factories started to research in the rubber. Sep 1972, Tianjin developed the first tacky rubber, thus they named it 729 (09. 1972).
The reason they do it in the tacky way is rather interesting. In the 1970s Chinese factories has little knowledge in sponge technology. It's hard to blown the sponge properly to develope it into a consistant porous sponge. We can't make the evenly porous sponge as the Japanease did, and we can't even make sponge of consistant hardness. The solution? Instead of making porous sponge, we made some less porous rubber-based sponge. Yes, sponge is normally made from some polymer. But due to the technology limitation, we make sponge using rubber. 0403名無しＱ(･∀･)ﾉ゜ｻｧﾝ!!2020/02/17(月) 04:07:58.83ID:kVkML9Ob But rubber sponge are much harder than polymer sponge. Therefore can't hold the ball and generate enough spin. Solution? They put an extra sticky layer on the top sheet rubber to make it as a tacky rubber. So instead of letting the sponge to hold the ball to generate spin like the Japanease and German did, we use hard rubber-based sponge + tacky topsheet to generate spin. Turns out it works well. 0404名無しＱ(･∀･)ﾉ゜ｻｧﾝ!!2020/02/17(月) 04:08:22.01ID:kVkML9Ob That's the story of how Chinese invented the tacky rubber. There are more background on this topic on why later on Chinese players don't use non-tacky rubber or why european players don't use tacky rubber. You can find it here, but you need to google translate though. https://bbs.hupu.com/19974400.html0405名無しＱ(･∀･)ﾉ゜ｻｧﾝ!!2020/02/17(月) 05:54:18.76ID:RtYLWnkF 粘着性のトップシートは硬いスポンジしか作れなかった故の産物か 0406名無しＱ(･∀･)ﾉ゜ｻｧﾝ!!2020/02/17(月) 11:07:39.38ID:RXdgSxBJ つかゴムでスポンジ作るってどんなよ… 0407名無しＱ(･∀･)ﾉ゜ｻｧﾝ!!2020/02/17(月) 14:25:22.91ID:sh1ZpOyF ゴムに発泡剤混ぜて焼き固めるとスポンジになるんだよ
