PP短纤维针刺非织造土工布的生产工艺有哪些？

在(zai)设置土工(gong)布(bu)(bu)隔断(duan)(duan)层时，土工(gong)布(bu)(bu)的(de)选择(ze)是关键。土工(gong)布(bu)(bu)的(de)选择(ze)应根据其使用位置和用途以及(ji)隔断(duan)(duan)层对土工(gong)布(bu)(bu)顶部断(duan)(duan)裂系数、渗(shen)透系数、耐老化性和抗冻性的(de)性能(neng)要求(qiu)进行选择(ze)。对于盐渍土地区(qu)，土工(gong)布(bu)(bu)除了考虑(lv)上述性能(neng)要求(qiu)外，还应考虑(lv)其耐腐蚀性。

PP非织造土(tu)工(gong)(gong)(gong)(gong)布的主要生产工(gong)(gong)(gong)(gong)艺有两种(zhong)：短(duan)纤(xian)维(wei)(wei)(wei)针(zhen)刺(ci)(ci)(ci)法(fa)和(he)长丝纺粘针(zhen)刺(ci)(ci)(ci)法(fa)。短(duan)纤(xian)维(wei)(wei)(wei)针(zhen)刺(ci)(ci)(ci)法(fa)是利用(yong)梳理机(ji)(ji)或开松(song)机(ji)(ji)将PP短(duan)纤(xian)维(wei)(wei)(wei)制(zhi)成短(duan)纤(xian)维(wei)(wei)(wei)网，通过气流(liu)成网机(ji)(ji)制(zhi)直接(jie)铺设成纤(xian)维(wei)(wei)(wei)随机(ji)(ji)排(pai)列的纤(xian)维(wei)(wei)(wei)网，然后通过针(zhen)刺(ci)(ci)(ci)工(gong)(gong)(gong)(gong)艺加固(gu)，使(shi)纤(xian)维(wei)(wei)(wei)相(xiang)互交叉缠绕，形成PP短(duan)纤(xian)维(wei)(wei)(wei)针(zhen)刺(ci)(ci)(ci)非织造土(tu)工(gong)(gong)(gong)(gong)布。PP短(duan)纤(xian)维(wei)(wei)(wei)针(zhen)刺(ci)(ci)(ci)非织造土(tu)工(gong)(gong)(gong)(gong)布结构蓬松(song)，密度和(he)厚度高，吸水(shui)渗水(shui)性能好(hao)，适用(yong)于过滤(lv)排(pai)水(shui)工(gong)(gong)(gong)(gong)程领域。然而，PP短(duan)纤(xian)维(wei)(wei)(wei)针(zhen)刺(ci)(ci)(ci)非织造土(tu)工(gong)(gong)(gong)(gong)布中纤(xian)维(wei)(wei)(wei)之间的粘合(he)力较(jiao)小。当外力较(jiao)大(da)时(shi)，容易产生纤(xian)维(wei)(wei)(wei)滑脱或位移，导致PP短(duan)纤(xian)维(wei)(wei)(wei)针(zhen)刺(ci)(ci)(ci)非织造土(tu)工(gong)(gong)(gong)(gong)布撕裂(lie)。

纺(fang)粘法具有工艺流程短、生(sheng)(sheng)产(chan)速(su)(su)度快、产(chan)量高(gao)、对环境无不利影响等(deng)优点。因此，它发展迅速(su)(su)，但设备投资成(cheng)(cheng)本(ben)相对较高(gao)，适(shi)合大(da)规模生(sheng)(sheng)产(chan)。长(zhang)丝(si)(si)(si)纺(fang)粘针法是将(jiang)(jiang)PP片加(jia)热，挤压(ya)熔融成(cheng)(cheng)熔体(ti)，然(ran)(ran)后通(tong)过(guo)喷丝(si)(si)(si)板喷出。冷却(que)装置(zhi)冷却(que)后，通(tong)过(guo)气流拉(la)伸或机械拉(la)伸成(cheng)(cheng)大(da)量细(xi)长(zhang)丝(si)(si)(si)，然(ran)(ran)后在网(wang)帘上乱(luan)铺，形成(cheng)(cheng)纤(xian)维(wei)网(wang)，然(ran)(ran)后通(tong)过(guo)针刺(ci)工艺将(jiang)(jiang)纤(xian)维(wei)网(wang)固定成(cheng)(cheng)布(bu)。在纺(fang)粘性(xing)无纺(fang)布(bu)生(sheng)(sheng)产(chan)中，由(you)于(yu)需要连(lian)续纺(fang)丝(si)(si)(si)、牵伸、铺网(wang)，纺(fang)丝(si)(si)(si)速(su)(su)度快，所用原料的(de)熔体(ti)流量或熔化指数较大(da)，一(yi)般为(wei)30~40g/（10min）。

PP纺(fang)丝针(zhen)刺非(fei)(fei)(fei)织(zhi)造(zao)(zao)土(tu)(tu)(tu)工布具有优(you)异的耐酸碱性(xing)和(he)化学稳(wen)定性(xing)，在(zai)复杂(za)的化学环(huan)境下，其耐久性(xing)明(ming)显优(you)于PET纺(fang)丝针(zhen)刺非(fei)(fei)(fei)织(zhi)造(zao)(zao)土(tu)(tu)(tu)工布。虽然PP短纤维针(zhen)刺非(fei)(fei)(fei)织(zhi)造(zao)(zao)土(tu)(tu)(tu)工布也具有良(liang)好(hao)的耐久性(xing)，但其强(qiang)延伸性(xing)能(neng)和(he)过滤(lv)性(xing)能(neng)远(yuan)不如PP纺(fang)粘性(xing)针(zhen)刺非(fei)(fei)(fei)织(zhi)造(zao)(zao)土(tu)(tu)(tu)工布。因此(ci)，发展PP纺(fang)丝针(zhen)刺非(fei)(fei)(fei)织(zhi)造(zao)(zao)土(tu)(tu)(tu)工布是(shi)极其必要(yao)的。