一、紗線捻度是什么意思
紗線捻度是指為使紗線具有一定的(de)強力、彈性、伸(shen)長(chang)、光澤、手感等(deng)物理(li)機械性能(neng),必須通過(guo)加(jia)捻(nian)(nian)改變(bian)棉紗(sha)(sha),由纖維(wei)結構來實(shi)現紗(sha)(sha)線(xian)加(jia)捻(nian)(nian),其實(shi)就是利(li)用棉紗(sha)(sha)橫(heng)截面(mian)間產生相對角位移,使原(yuan)來伸(shen)直平行(xing)之纖維(wei)與紗(sha)(sha)軸發生傾斜來改變(bian)紗(sha)(sha)線(xian)結構,粗(cu)條在(zai)加(jia)捻(nian)(nian)過(guo)程由寬度逐(zhu)(zhu)漸收(shou)縮,兩(liang)側(ce)逐(zhu)(zhu)漸折迭(die)而(er)卷入紗(sha)(sha)線(xian)條中(zhong)心(xin),形(xing)(xing)(xing)成加(jia)捻(nian)(nian)三(san)角形(xing)(xing)(xing),在(zai)加(jia)捻(nian)(nian)三(san)角形(xing)(xing)(xing)中(zhong),棉條的(de)寬度和截面(mian)發生變(bian)化,從扁平帶(dai)狀,逐(zhu)(zhu)漸成圓柱(zhu)形(xing)(xing)(xing)的(de)紗(sha)(sha)。
二、紗線捻度的測定方法有哪些
1、退捻法:用于短纖維純紡、混紡(環錠(ding)紡、走錠(ding)紡、翼錠(ding)紡)的股(gu)線中較粗者和加捻(nian)(nian)(nian)的長絲。退捻(nian)(nian)(nian)至纖維平行,計數(shu)紗線單位長度的退捻(nian)(nian)(nian)轉數(shu)。
2、退捻加捻法:短纖(xian)維(wei)傳統紡紗中較細的(de)紗線(xian),用退(tui)捻(nian)(nian)再反向(xiang)加(jia)捻(nian)(nian)使(shi)(shi)紗線(xian)伸長(chang)(chang)后又縮回到原長(chang)(chang),用所(suo)加(jia)轉數的(de)半作此(ci)段(duan)紗線(xian)捻(nian)(nian)數。近(jin)來又發(fa)展了二(er)次退(tui)捻(nian)(nian)加(jia)捻(nian)(nian)法、三次退(tui)捻(nian)(nian)加(jia)捻(nian)(nian)法及四次退(tui)捻(nian)(nian)加(jia)捻(nian)(nian)法等。目(mu)的(de)是消除纖(xian)維(wei)須條反向(xiang)加(jia)捻(nian)(nian)時結構的(de)變化(hua)。但也可(ke)能引起紗線(xian)結構變化(hua)而使(shi)(shi)測試結果(guo)失準。
3、反光法:用(yong)平行光束照射(she)紗(sha)線,測量反(fan)射(she)光峰值偏(pian)轉的角度,占計加捻(nian)紗(sha)線表層螺旋角計算捻(nian)度。
對于轉杯紡(fang)、靜(jing)電窈、噴(pen)氣紡(fang)、賽(sai)洛紡(fang)、自(zi)捻(nian)(nian)紡(fang)等新型紗(sha)線(xian)的(de)捻(nian)(nian)度,由于結構(gou)不(bu)同(tong),特(te)別(bie)紗(sha)線(xian)皮芯捻(nian)(nian)數不(bu)同(tong)甚至不(bu)同(tong)捻(nian)(nian)向。應設法(fa)分(fen)(fen)層(ceng)分(fen)(fen)別(bie)測試并(bing)分(fen)(fen)別(bie)發(fa)展不(bu)同(tong)的(de)測試方法(fa)。