韓雨蘭 宋兵 李春霖 杜遠(yuǎn)遠(yuǎn) 牛家?guī)V
摘 要:與傳統(tǒng)溶劑型聚氨酯相比,水性聚氨酯(WPU)大大減少了有機(jī)溶劑的使用,可有效降低環(huán)境污染,正越來越受到人們的關(guān)注。然而,WPU中親水基團(tuán)的引入會影響其力學(xué)性能,限制了WPU產(chǎn)品的使用范圍。本文對WPU組成結(jié)構(gòu)和力學(xué)性能之間的關(guān)系進(jìn)行了闡述,并對WPU染色方面的研究現(xiàn)狀做了介紹和總結(jié),以期為水性聚氨酯超纖革的開發(fā)提供借鑒和參考。
關(guān)鍵詞:水性聚氨酯;親水基團(tuán);組成結(jié)構(gòu);力學(xué)性能;超細(xì)纖維合成革;染色
中圖分類號:TS193.8
文獻(xiàn)標(biāo)志碼:A
文章編號:1009-265X(2023)03-0225-12
基金項(xiàng)目:技術(shù)開發(fā)類橫向合作項(xiàng)目(21-02-101-0375)
作者簡介:韓雨蘭(1998—),女,江蘇鹽城人,碩士研究生,主要從事水性聚氨酯及超纖革染色方面的研究。
通信作者:牛家?guī)V, E-mail:niujiarong@tiangong.edu.cn
聚氨酯(Polyurethane, PU)是以氨基甲酸酯基(—NHCOO—)為重復(fù)單元,由異氰酸酯和帶有活潑氫的二元醇、多元醇化合物等加聚而成的一類聚合物[1]。聚氨酯在合成過程中結(jié)構(gòu)易于調(diào)控,性能多樣,能滿足皮革、家具、建筑等多領(lǐng)域的需求。聚氨酯根據(jù)分散介質(zhì)的不同,可分為溶劑型聚氨酯和水性聚氨酯,由于溶劑型聚氨酯在合成和使用過程中用到大量的有機(jī)溶劑,會產(chǎn)生大量易揮發(fā)有機(jī)化合物(VOCs),容易對環(huán)境造成嚴(yán)重污染,而水性聚氨酯(Waterborne polyurethane, WPU)是以水為分散介質(zhì)的乳液,在生產(chǎn)和使用過程中減少了有機(jī)溶劑的使用,比傳統(tǒng)的溶劑型聚氨酯更環(huán)保[2],越來越受到研究者的關(guān)注。
WPU成膜力、柔順性和耐磨性好,且耐低溫、黏度易于調(diào)節(jié)、成本較低,在涂料、油墨、黏合劑、紡織品整理等方面都有著廣泛的應(yīng)用[3-4]。Fang等[5]合成了具有低玻璃化轉(zhuǎn)變溫度(Tg)的納米水性聚氨酯,該材料具有良好的熱穩(wěn)定性和低結(jié)晶度,適合做水性油墨黏合劑。Zhang等[3]制備了一種耐腐蝕的水性聚氨酯改性環(huán)氧樹脂。經(jīng)固化處理的固化膜相較于原始膜具有更高的耐熱性,能經(jīng)受約60天的鹽霧腐蝕實(shí)驗(yàn),在對金屬材料的保護(hù)上有著許多潛在應(yīng)用。WPU在羊毛表面形成薄膜可以降低定向摩擦效應(yīng)[4],因此能夠用作羊毛織物的防氈縮整理劑[6-8]。
WPU主鏈結(jié)構(gòu)與天然皮革中的膠原蛋白相似,生產(chǎn)和使用工藝環(huán)保,因此在超細(xì)纖維合成革(超纖革)的開發(fā)與應(yīng)用上受到廣泛的關(guān)注。超細(xì)纖維聚氨酯合成革作為新一代的合成革,經(jīng)過不斷的完善,其外觀和性能可以與天然皮革相媲美,在鞋服、箱包、家具、汽車等行業(yè)有著廣泛的應(yīng)用。但是,由于親水性單體的引入,水性聚氨酯制備的超纖革在很多性能上與傳統(tǒng)的溶劑型聚氨酯超纖革有明顯區(qū)別,尤其在力學(xué)和染色性能方面的差異更為突出。為進(jìn)一步提高水性聚氨酯超纖革的性能,為高物性產(chǎn)品的開發(fā)提供參考,本文介紹了水性聚氨酯的構(gòu)成、對力學(xué)性能的影響及相關(guān)研究進(jìn)展,總結(jié)了水性聚氨酯及其超纖革在染色、著色方面的研究現(xiàn)狀。
1 水性聚氨酯的主要合成原料
聚氨酯由二(多)異氰酸酯和二(多)元醇交替排列組成,微觀結(jié)構(gòu)上由軟、硬段形成嵌段共聚物[9]。區(qū)別于溶劑型聚氨酯,WPU的分子結(jié)構(gòu)中引入了離子側(cè)基或親水鏈段,使其具有自乳化性能,且能夠以水取代有機(jī)溶劑作為分散介質(zhì),使水性聚氨酯在生產(chǎn)和加工過程中符合綠色環(huán)保的要求。異氰酸酯、小分子多元醇、擴(kuò)鏈劑及親水基團(tuán)作為WPU主要合成原料,其性能的差異對最終所制備的水性聚氨酯均會產(chǎn)生不同的影響。
1.1 異氰酸酯
水性聚氨酯硬段結(jié)構(gòu)中的異氰酸酯大都含有兩個或兩個以上的異氰酸酯基(—NCO),主要分為芳香族異氰酸酯和脂肪族異氰酸酯。芳香族異氰酸酯含有苯環(huán)結(jié)構(gòu),反應(yīng)活性較高,在制備過程中需嚴(yán)格控制反應(yīng)條件。芳香族聚氨酯中的剛性苯環(huán)結(jié)構(gòu)及
生成的氨基甲酸酯結(jié)構(gòu),使聚氨酯大分子具有較強(qiáng)的內(nèi)聚力,因此其力學(xué)性能及耐溶劑性能優(yōu)于脂肪族聚氨酯[10],但因分子中存在苯環(huán)雙鍵發(fā)色結(jié)構(gòu),其抗紫外線性能差,易變黃[11-13]。在水性聚氨酯的合成工藝中,較為常用的芳香族異氰酸酯是甲苯二異氰酸酯(TDI)和二苯基甲烷二異氰酸酯(MDI),在早期的研究中也有對亞苯基二異氰酸酯(PPDI)。此外,脂肪族異氰酸酯的常見結(jié)構(gòu)有異佛爾酮二異氰酸酯(IPDI)、六亞甲基二異氰酸酯(HDI)、二聚酸二異氰酸酯(DDI)和4,4′-二環(huán)乙基甲烷二異氰酸酯(HMDI)等[14-16]。異氰酸酯結(jié)構(gòu)及對WPU性能的影響見表1[17-21]。
1.2 低聚物多元醇
水性聚氨酯的軟段結(jié)構(gòu)主要為官能度2~3的低聚物多元醇類,一般可分為聚酯多元醇和聚醚多元醇兩大類[22-23]。目前較為常見的WPU用聚酯多元醇有己二酸系列聚酯多元醇、聚己內(nèi)酯二醇(PCL)和聚碳酸酯二醇(PCDL)等。通常聚酯多元醇的分子量較低,且具有支鏈結(jié)構(gòu),含有的酯基、羥基、羧基等基團(tuán)可在后續(xù)反應(yīng)中進(jìn)行交聯(lián)反應(yīng)[24],其中酯鍵可賦予水性聚氨酯良好的力學(xué)性能和機(jī)械強(qiáng)度[11],但酯鍵易水解,其耐水性能相較于聚醚多元醇差。常用的聚醚多元醇主要有聚四氫呋喃(PTMGE)、聚丙二醇PPG、聚乙二醇(PEG)等。一般來說,聚醚多元醇中醚鍵的內(nèi)聚能低、且易于旋轉(zhuǎn),由其制備的水性聚氨酯具有較好的低溫柔順性和疏水性[11],但其機(jī)械強(qiáng)度低,易老化。
1.3 擴(kuò)鏈劑
在聚氨酯合成過程中,小分子擴(kuò)鏈劑不僅能夠調(diào)節(jié)聚氨酯分子量,還可以調(diào)節(jié)軟硬段之間的比例,改善材料性能。小分子擴(kuò)鏈劑主要分為醇類和胺類,醇類擴(kuò)鏈劑是預(yù)聚反應(yīng)中常用的擴(kuò)鏈劑,較為常見的有乙二醇(EG)、1,4-丁二醇(1,4-BDO)、三羥甲基丙烷(TMP)等;胺類擴(kuò)鏈劑與異氰酸酯基團(tuán)反應(yīng)速度快,能夠生成極性較強(qiáng)的脲鍵[14],由二元胺擴(kuò)鏈生成的聚氨酯強(qiáng)度大、模量高,黏附性和耐低溫性能優(yōu)良。胺類擴(kuò)鏈劑主要有脂肪族和脂環(huán)族二胺或三胺、以氨封端的聚醚、肼及其衍生物。
1.4 親水單體
水性聚氨酯的制備過程需要引入親水性基團(tuán),常用的方法有擴(kuò)鏈法、接枝法和多元醇親水改性等。其中,親水單體擴(kuò)鏈法因操作簡便、適用性強(qiáng)等優(yōu)點(diǎn),是目前較為常用的方法。
依據(jù)親水基團(tuán)的離子特性,親水?dāng)U鏈劑可分為陽離子、陰離子、非離子和兩性離子親水?dāng)U鏈劑[25]。陽離子聚氨酯一般可選用叔胺化合物進(jìn)行親水?dāng)U鏈,或利用含鹵素化合物通過親核反應(yīng)將陽離子引入到主鏈上[26]。陽離子水性聚氨酯具有抗菌性能,使其在衛(wèi)生健康領(lǐng)域有著廣泛應(yīng)用,但陽離子型親水?dāng)U鏈劑中的季銨鹽會降低水性聚氨酯的耐熱性。而非離子型擴(kuò)鏈劑中的環(huán)氧乙烯基會對水性聚氨酯的耐水性能造成一定的影響[27]。目前較為常見的水性聚氨酯大都為陰離子型WPU,引入的親水基團(tuán)主要包含磺酸型、羧酸型兩大類水性單體[25,28,29]。常用的水性單體及性能見表2。
2 水性聚氨酯力學(xué)性能影響
聚氨酯是軟、硬段交替排列的嵌段共聚物,軟、硬段間的不相容性使聚氨酯存在微相分離[30]。離子基團(tuán)的類型和含量、多元醇結(jié)構(gòu)、擴(kuò)鏈劑類型等因素對水性聚氨酯性能均有著重要的影響。
2.1 硬段對WPU性能的影響
在聚氨酯分子結(jié)構(gòu)中,硬段約占40%,主要是由異氰酸酯基參與合成反應(yīng)后所生成。異氰酸酯基化學(xué)性質(zhì)活潑,能夠與羥基、氨基、氨基甲酸酯基、脲基、水等反應(yīng)[31]。其常見反應(yīng)如圖1所示。
聚氨酯硬段易形成氫鍵,有緊湊的晶體結(jié)構(gòu),使聚合物具有一定的剛性,賦予聚氨酯良好的拉伸強(qiáng)度和彈性恢復(fù)力。異氰酸酯結(jié)構(gòu)及含量對水性聚氨酯的結(jié)晶及機(jī)械性能影響較為顯著[20,32]。如二苯基甲基二異氰酸酯分子鏈段規(guī)整,由此制備的聚氨酯結(jié)晶性能較高,機(jī)械性能較為優(yōu)良。Xiao等[33]以二苯基甲基二異氰酸酯為原料,二羥甲基丙酸(DMPA)為親水基團(tuán),采用兩步聚合法合成了水性聚氨酯(MWPU),與異佛爾酮二異氰酸酯型水性聚氨酯(IWPU)進(jìn)行了對比和分析。研究發(fā)現(xiàn)二苯基甲基二異氰酸酯的雙苯環(huán)結(jié)構(gòu)使WPU鏈段間的相分離程度增大,鏈段間的氫鍵作用增強(qiáng),從而使得MWPU的機(jī)械性能和耐水性均高于IWPU。
王珂等[34]以異佛爾酮二異氰酸酯和聚酯多元醇為反應(yīng)物,采用預(yù)聚混合法合成了一系列硬段含量不同的脂肪族WPU,發(fā)現(xiàn):當(dāng)親水基團(tuán)DMPA含量固定時,隨著硬段含量的增加,分子中的氨基甲酸酯基和脲基增多,微相分離程度也增加。拉伸強(qiáng)度隨硬段含量的增加先增大后減小,在30%時達(dá)到最高值52 MPa;斷裂伸長率隨硬段含量增加而減小。吸水率也出現(xiàn)先增大后減小的趨勢,在硬段含量為40%時耐水性最好,吸水率低于8%。
擴(kuò)鏈劑在聚氨酯合成過程中不僅能夠有效調(diào)節(jié)分子量,也可以參與硬段的形成,影響聚氨酯的力學(xué)性能。Orgiles-Calpena等[35]分別以1,4-丁二醇、1,6-己二醇和肼作為擴(kuò)鏈劑研究擴(kuò)鏈劑類型對聚氨酯性能的影響。經(jīng)DSC測試發(fā)現(xiàn),擴(kuò)鏈劑的類型對玻璃化轉(zhuǎn)變溫度、結(jié)晶度、相分離程度均有一定程度的影響:以肼為擴(kuò)鏈劑時,因硬段結(jié)構(gòu)中脲基的存在,聚合物剛度大,結(jié)晶分?jǐn)?shù)?。辉谝远甲鳛閿U(kuò)鏈劑時,隨著擴(kuò)鏈劑長度的增加,聚氨酯的軟、硬段相分離程度增加,從而導(dǎo)致聚氨酯結(jié)晶度較高,力學(xué)性能較好。
2.2 軟段對WPU性能的影響
構(gòu)成水性聚氨酯軟段的低聚多元醇,一般都具有較低的玻璃化轉(zhuǎn)變溫度(Tg),軟段結(jié)構(gòu)的變化會引起聚氨酯不同程度的相分離。薛振華等[31]以6種分子量相同、結(jié)構(gòu)不同的多元醇(見表4)制備了含有不同軟段結(jié)構(gòu)的WPU乳液。研究發(fā)現(xiàn),以聚酯多元醇為軟段的WPU膠膜的100%模量和拉伸強(qiáng)度普遍高于聚醚型WPU。這是因?yàn)榫埘ブ械聂驶扛撸軌蛱峁└玫慕Y(jié)晶性能,且酯鍵剛性較醚鍵強(qiáng),從而使其力學(xué)性能有所提升。含支鏈的WPU相較于直鏈WPU耐熱性和綜合力學(xué)性能低,但膜表面更光滑。
聚碳酸酯二醇通常具有較高的水解穩(wěn)定性和耐低溫性能,在水性聚氨酯中作為軟段結(jié)構(gòu)可賦予其更好的性能。Garcia等[36]比較了分子量近似的聚碳酸酯、聚酯、聚醚多元醇對WPU涂層性能的影響。研究發(fā)現(xiàn),因聚碳酸酯WPU的相分離程度高,涂層具有較短的干燥時間和較好的剪切附著力,涂層光澤性更好,耐乙醇化學(xué)性及泛黃度均優(yōu)于其它WPU。
2.3 親水單體對WPU性能的影響
在水性聚氨酯的制備過程中,親水單體所占比例較小,但其對WPU的分散穩(wěn)定性、耐溶劑性和耐水性能等影響很大。
二羥甲基丙酸(DMPA)中—OH與異氰酸酯基的反應(yīng)溫和,常作為羧酸型親水單體用于WPU的制備[37]。DMPA增加了聚氨酯軟、硬段間的微相分離,可影響水性聚氨酯的結(jié)晶性[38]。Hu等[39]以IPDI、PCDL、DMPA為原料,通過預(yù)聚法制備了DMPA含量不同的水性聚氨酯,研究了親水單體含量對WPU力學(xué)性能的影響,如圖2所示。
由圖2可知,隨著DMPA含量的增加,抗拉伸強(qiáng)度先增加后降低,斷裂伸長率不斷減小。這是因?yàn)殡S著分子鏈中DMPA的增加,硬段增加,分子柔性下降,分子內(nèi)氫鍵和內(nèi)聚能增加,分子結(jié)構(gòu)中的微相分離明顯,從而導(dǎo)致拉伸強(qiáng)度提高,斷裂伸長率下降。另外,熱重分析表明,隨著DMPA的增加,WPU的初始熱分解溫度降低,這是因?yàn)橛捕蜗扔谲浂畏纸?,硬段的增加降低了材料分解溫度?/p>
磺酸型水性聚氨酯固含量高、穩(wěn)定性好、耐熱性好,在水性聚氨酯領(lǐng)域中受到廣泛的研究。Honarkar等[28]以N,N-二(2-羥乙基)-2氨基乙磺酸鈉(BES)為親水單體,通過預(yù)聚體法制備WPU,研究了磺酸基的引入量對WPU熱穩(wěn)定性和力學(xué)性能的影響(見表5)。由表5可以看到,隨著BES含量的增加,WPU的各熱分解溫度不斷提升,熱穩(wěn)定性提高。這是由于磺酸鈉基團(tuán)可通過庫侖力和氫鍵引起鏈間作用,從而使穩(wěn)定性提升。
力學(xué)性能測試可知,WPU膜的拉伸斷裂強(qiáng)度隨著BES的增加也不斷的提高。這是因?yàn)锽ES中的—SO-3Na+可完全電離,當(dāng)BES含量增加時氨基甲酸酯鍵間的氫鍵作用力及離子中心的庫侖力增加,使聚氨酯熱穩(wěn)定性和拉伸強(qiáng)度提高。
郭旭東[25]以BES-Na、1,2-二羥基-3-丙酯磺酸鈉(DEPS)為親水?dāng)U鏈劑,含磺酸基的聚酯多元醇(BY-3033)為親水軟鏈段,制備了3種高固含量的WPU。并探討磺酸鹽親水?dāng)U鏈劑的分子結(jié)構(gòu)及親水基位置對WPU性能的影響。研究發(fā)現(xiàn):當(dāng)3種反應(yīng)物質(zhì)量分?jǐn)?shù)分別為8%、5%和50%時所制備的水性聚氨酯固含量均可達(dá)到45%以上;3種水性聚氨酯均具有較高的熱穩(wěn)定性、透明度和耐水性。BES-Na制備的WPU相比于DEPS制備的WPU結(jié)晶度更高,這是因?yàn)閷ΨQ結(jié)構(gòu)的小分子親水?dāng)U鏈劑有利于WPU結(jié)晶度的提高;含有磺酸根的聚酯多元醇制備的WPU具有更高的結(jié)晶性。力學(xué)性能測試顯示親水基團(tuán)位于軟段時更有利于WPU強(qiáng)力的提高。
2.4 改性材料對WPU性能的影響
在水性聚氨酯的制備過程中,為了獲得更好的應(yīng)用性能,往往會對其進(jìn)行適當(dāng)?shù)母男浴3S玫母男圆牧峡偨Y(jié)于表6。
除上述高分子化合物外,納米材料和生物質(zhì)材料對WPU的改性也受到廣泛的研究。通過共混、原位聚合等方法將納米材料引入WPU或使WPU納米化,利用納米材料的表面效應(yīng)、光學(xué)效應(yīng)、小尺寸效應(yīng)等特性,可使改性后的水性聚氨酯獲得新功能或更好的性能[48-49]。生物質(zhì)材料資源豐富,可再生性和生物相容性好,價格低廉。近年來不少研究將生物質(zhì)材料如纖維素、植物油、角蛋白等應(yīng)用到水性聚氨酯的改性中,有效的改善了水性聚氨酯的穩(wěn)定性、生物可降解性,在提高WPU的應(yīng)用性能方面取得了明顯的進(jìn)展[50-51]。
3 水性聚氨酯的染色
近年來,隨著合成工藝的不斷進(jìn)步和成熟,WPU的性能不斷提高,尤其在超細(xì)纖維合成革的開發(fā)上日益受到相關(guān)產(chǎn)業(yè)的重視。通過顏料(或染料)共混著色和染色的方式,可使超纖革獲得豐富的色彩,更好的滿足市場需求。
3.1 聚氨酯超纖革的染色
常見的溶劑型聚氨酯因結(jié)構(gòu)中缺少離子基團(tuán),對染料的吸附能力較差,易造成染色不勻,色牢度差等問題[52]。超纖革因PU和基布纖維兩組分染色性能的差異易出現(xiàn)勻染性、滲透性和色牢度等染色問題[53]。在溶劑型PU超纖革的染色中,常從染料類型[54]、染色助劑(勻染劑、滲透劑、固色劑)[55-57]、染色工藝[58-59]、基布改性[60-63]等方面來改善。關(guān)于溶劑型聚氨酯合成革的染色,雖然實(shí)際生產(chǎn)中還存在一些問題,但是總體而言染色工藝比較成熟,國內(nèi)外有很多相關(guān)的研究和文獻(xiàn),本文不再贅述。
水性聚氨酯由于分子中親水性單體的引入,染色性能發(fā)生了很大的變化。首先,離子型WPU電離的親水性基團(tuán)可以作為能夠與染料結(jié)合的染座,通過庫侖力與染料結(jié)合,從這個角度來看其染色性能得到了改善。其次,根據(jù)反應(yīng)物的不同,受軟硬鏈段比例和水性側(cè)基的影響,WPU的微觀結(jié)構(gòu)不同于溶劑型PU,染料與WPU的親和力不同,染料在染色過程中對WPU的吸附和擴(kuò)散行為不同,這會導(dǎo)致很多適合溶劑型PU超纖革染色的染料或上染條件不再適用。另外,在筆者的實(shí)踐中發(fā)現(xiàn),WPU超纖革透染性差,染色濕牢度、色遷移牢度差,固色困難。因此,對于WPU超纖革的染色需做深入而系統(tǒng)的研究。
3.2 有色WPU
無論染料還是顏料,色素都需要通過一定的工藝和設(shè)備才能與被染物結(jié)合。在染色過程中,大多數(shù)染料與被染物之間基本是物理結(jié)合,存在各種各樣的色牢度問題。將發(fā)色基團(tuán)或染料通過化學(xué)方法引入WPU,使之與WPU分子形成化學(xué)結(jié)合,可以有效改善牢度問題,使用方便。
異氰酸酯基反應(yīng)性能活潑,將含有活潑氫的有機(jī)染料接枝到聚氨酯中,可以得到含發(fā)色基團(tuán)的WPU[64]。發(fā)色基團(tuán)可在聚氨酯鏈的主鏈或側(cè)鏈上引入。
Zheng等[65]以異佛爾酮二異氰酸酯、聚醚乙二醇、二羥甲基丙酸為原料,以自制的N,N-2-(2-羥基乙基)-4-苯基偶氮苯胺(HPB)為擴(kuò)鏈劑,成功地將偶氮發(fā)色基團(tuán)通過共價鍵連接到了聚氨酯大分子中,制備出有色WPU,且水性聚氨酯的熱穩(wěn)定性和耐水性因HPB的剛性芳香結(jié)構(gòu)而有所提高。
Zhao等[66]將2,6-二氨基蒽醌結(jié)構(gòu)引入到水性聚氨酯結(jié)構(gòu)中,制備了黃色WPU,并對WPU薄膜和用其染色的棉布的顏色特征進(jìn)行了評價。棉布耐干、濕摩擦色牢度可達(dá)到4~5級,并且經(jīng)皂洗后無明顯褪色。
Wang等[67]以端羥基水性聚氨酯和活性染料反應(yīng),制得自著色水性聚氨酯,并將其應(yīng)用到超細(xì)纖維合成革的制備中。使用自著色WPU制備的超纖革表面顏色比以傳統(tǒng)染色方法染色的超纖革顏色深,且超纖革耐水洗牢度可達(dá)到3級以上。
Wang等[68]將T/N非織造布浸入含硅陰離子水性聚氨酯并與活性染料“接枝”,反應(yīng)機(jī)理如圖3所示。由于活性染料能夠與水性聚氨酯中的—OH反應(yīng),影響了水性聚氨酯的交聯(lián),從而使有色合成革的最大斷裂強(qiáng)度和拉伸率有所下降。在染料用量為6% (o.w.f)的時候,具有側(cè)—OH的水性聚氨酯的上染率在80%以上,最高可達(dá)到96.1%,且耐水洗牢度可達(dá)4~5級。
通過接枝的方法將發(fā)色基團(tuán)或染料引入到聚氨酯結(jié)構(gòu)中,一定程度上提高了WPU的耐水洗牢度和上染率,改善了WPU產(chǎn)品染色工藝面臨的問題,但產(chǎn)品暗淡而單一。
還有研究者從化學(xué)結(jié)構(gòu)入手,調(diào)整、改善聚氨酯的染色性能。Liu等[69]研究了一種酸性可染聚氨酯,此類聚氨酯可通過對軟、硬段間相分離程度的調(diào)控使聚氨酯呈現(xiàn)完全無定形狀態(tài),使染料擴(kuò)散到聚合物中。與普通聚氨酯相比,酸性可染聚氨酯對酸性染料的染色速度快,上染率高,且具有更好的濕摩擦牢度和耐洗滌牢度,在超纖革上有著較好的應(yīng)用前景。
4 結(jié) 語
聚氨酯的嵌段結(jié)構(gòu)使其具有良好的拉伸強(qiáng)度和彈性,通過對軟、硬鏈段比例和微晶相分離程度的調(diào)控能夠有效調(diào)整其力學(xué)性能。在陰離子水性聚氨酯中,通過對羧酸鹽、磺酸鹽種類及含量的調(diào)控可以改善其力學(xué)性能及熱穩(wěn)定性。水性超纖革的透染性及色牢度差,固色困難。通過染料接枝的方法,將含有活潑氫的有機(jī)染料接枝到水性聚氨酯中,可改善色牢度。但產(chǎn)品顏色過于單一,無法大范圍的應(yīng)用于超纖革的染色中。
目前,對水性聚氨酯的合成及構(gòu)效關(guān)系的研究較多,但對水性聚氨酯及WPU超纖革染色性能和機(jī)理的研究甚少。在筆者的實(shí)踐過程中發(fā)現(xiàn),水性聚氨酯在染色過程中存在一定程度的“凝膠化”,這種結(jié)構(gòu)變化直接影響其染透性、染色牢度、染色效率。對WPU及其超纖革的染色不能僅做工藝方面的研究,而要進(jìn)行深入而系統(tǒng)的研究,這樣才能滿足高質(zhì)量、高物性產(chǎn)品的開發(fā),推動WPU相關(guān)產(chǎn)業(yè)的發(fā)展。
參考文獻(xiàn):
[1]劉長偉,史穎,馬馳,等.異氰酸酯硬段對聚氨酯結(jié)構(gòu)及性能的影響[J].高分子材料科學(xué)與工程,2021,37(3):79-84.
LIU Changwei, SHI Ying, MA Chi, et al. Effect of isocyanate hard segment on structure and property of polyurethane[J]. Polymer Materials Science & Engineering, 2021,37(3): 79-84.
[2]凡永利,鄭水蓉,蘇航,等.水性聚氨酯改性及其應(yīng)用研究進(jìn)展[J].中國膠粘劑,2011,20(5):56-60.
FAN Yongli, ZHENG Shuirong, SU Hang, et al. Research progress of modification and application of waterborne polyurethane[J]. China Adhesives 2011, 20(5): 56-60.
[3]ZHANG J J, HUANG H, MA J, et al. Preparation andproperties of corrosion-resistant coatings from waterborne polyurethane modified epoxy emulsion[J]. Frontiers in Materials, 2019, 6: 185.
[4]杜壯.羊毛織物防氈縮整理及羊毛角蛋白的生物醫(yī)用研究[D].上海:東華大學(xué),2019.
DU Zhuang. Research on Anti-taping Treatment of Wool Fabric and Biomedical Application of Wool Keratin[D]. Shanghai: Donghua university, 2019.
[5]FANG C Q, ZHOU X, YU Q, et al. Synthesis and characterization of low crystalline waterborne polyurethane for potential application in water-based ink binder[J]. Progress in Organic Coatings, 2014, 77(1): 61-71.
[6]謝珍,杜壯,閻克路.蛋白酶和有機(jī)硅改性聚氨酯聯(lián)合防氈縮工藝[J].毛紡科技,2017,45(9):27-33.
XIE Zhen, DU Zhuang, YAN Kelu. Anti-felting process of wool fabric by protease and polysiloxane modified waterborne polyurethane[J]. Wool Textile Journal, 2017, 45(9):27-33.
[7]丁會會.功能性羊絨針織制品聚氨酯整理劑的研發(fā)與應(yīng)用[D].西安:西安工程大學(xué),2020.
DING Huihui. Development and Application of Functional Cashmere Knitted Polyurethane Finishing Agent[D]. Xi'an: Xi'an Polytechnic University, 2020.
[8]張冰,張弛,肖升木,等.改性蛋白酶的制備及其在羊毛防氈縮整理中的應(yīng)用[J].紡織學(xué)報,2012,33(5):74-80.
ZHANG Bing, ZHANG Chi, XIAO Shengmu, et al. Preparation of modified protease and its application on antifelting finishing of wool[J]. Journal of Textile Research, 2012, 33(5): 74-80.
[9]杜鵑.聚氨基甲酸酯彈性纖維的染色性能及染色原理研究[D].蘇州:蘇州大學(xué),2001.
DU Juan. A Study on the Behaviours and Principles of Dyeing for Polyurethane Fibers[D]. Suzhou: Suzhou University, 2001.
[10]SHAMSI R, MAHYARI M, KOOSHA M. Synthesis of CNT-polyurethane nanocomposites using ester-based polyols with different molecular structure: Mechanical, thermal, and electrical properties[J]. Journal of Applied Polymer Science, 2017, 134(10): 13.
[11]張賽楠.芳香族水性聚氨酯材料的合成及其性能研究[D].哈爾濱:黑龍江大學(xué),2018.
ZHANG Sainan. Synthesis and Properties of Aromatic Waterborne Polyurethane Materials[D]. Harbin: Heilongjiang University, 2018.
[12]邱峻,韋軍,王寶總,等.親水性封閉型芳香族異氰酸酯交聯(lián)劑的合成及性能研究[J].聚氨酯工業(yè),2011,26(6):39-42.
QIU Jun, WEI Jun, WANG Baozong, et al. Synthesis and performance research of waterborne blocked aromatic isocyanate crosslinking agent[J]. Polyurethane industry, 2011, 26(6): 39-42.
[13]崔海世.無溶劑型脂肪族聚氨酯合成與性能研究[D].長春:吉林大學(xué),2008.
CUI Haishi. Study on the Preparation and Properties of Aliphatic Polyurethane without Imprgnant[D]. Chang-chun: Jilin University, 2008.
[14]張基智.脂環(huán)族雙組分水性聚氨酯材料的合成及固化研究[D].哈爾濱:黑龍江大學(xué),2018.
ZHANG Jizhi. Study on Synthesis and Curing of Aliphatic Cyclic Two-component Aqueous Polyurethane[D]. Harbin: Heilongjiang University, 2018.
[15]夏會華.水性聚氨酯性能的影響因素[D].合肥:安徽大學(xué),2013.
XIA Huihua. Influencing Factors of Properties of Water-borne Polyurethane[D]. Hefei: Anhui University, 2013.
[16]YUAN F, LIU W B, Yang F, et al. Preparation and properties of MDI-based polyester polyurethane elastomer[J]. Polymers & Polymer Composites, 2014, 22(3): 341-346.
[17]常偉林,王建偉,池俊杰,等.二聚酸二異氰酸酯在水性聚氨酯中的應(yīng)用進(jìn)展[J].化學(xué)推進(jìn)劑與高分子材料,2017,15(1):35-39.
CHANG Weilin, WANG Jianwei, CHI Junjie, et al. Application progress of dimer acid diisocyanate in waterborne polyurethane[J]. Chemical Propellants and Polymer Materials, 2017, 15(1): 35-39.
[18]高喜平,王勃,曹光宇,等.異佛爾酮二異氰酸酯分子中異氰酸酯基團(tuán)活性比較[J].河南科技大學(xué)學(xué)報(自然科學(xué)版),2009,30(2):101-104,115.
GAO Xiping, WANG Bo, CAO Guangyu, et al. Active comparison of isocyanates in isophorone diisocyanatek[J]. Journal of Henan University of Science and Technology(Natural Science Edition), 2009, 30(2): 101-104,115.
[19]陳卓.六亞甲基二異氰酸酯固化劑的合成及結(jié)構(gòu)表征[D].廣州:華南理工大學(xué),2014.
CHEN Zhuo. The Synthesis and Characterization of HDI-based Curing Agent[D]. Guangzhou: South China University of Technology, 2014.
[20]BARIKANI M, EBRAHIMI M V, MOHAGHEGH S M S. Influence of diisocyanate structure on the synthesis and properties of ionic polyurethane dispersions[J]. Polymer-Plastics Technology and Engineering, 2007, 46(11): 1087-1092.
[21]冼文琪.二氧化碳基多元醇(PPCD)及水性聚氨酯的合成與應(yīng)用研究[D].廣州:廣東工業(yè)大學(xué),2021.
XIAN Wenqi. Synthesis and Application of CO2 based Polyols(PPCD) and Waterborne Polyurethane[D]. Guangzhou: Guangdong University of Technology, 2021.
[22]石磊,楊浩,沈連根,等.無溶劑聚氨酯合成革技術(shù)的研究進(jìn)展[J].現(xiàn)代紡織技術(shù),2021,29(1):76-81.
SHI Lei, YANG Hao, SHEN Liangen, et al. Research progress of solvent-free polyurethane synthetic leather technology[J]. Advanced Textile Technology, 2021, 29(1): 76-81.
[23]SUN Z, FAN H J, Chen Y, et al. Synthesis of self-matting waterborne polyurethane coatings with excellent transmittance[J]. Polymer International, 2018, 67(1): 78-84.
[24]龐燦.聚酯多元醇合成工藝研究及其在水性聚氨酯塑料涂層中的應(yīng)用[D].合肥:合肥工業(yè)大學(xué),2017.
PANG Cai. Study on Synthesis of Polyester Polyol and Its Application in Waterborne Polyurethane Plastic Coatings[D]. Hefei: Hefei University of Technology, 2017.
[25]郭旭東.基于羥基磺酸型親水?dāng)U鏈劑制備高固含量水性聚氨酯及其性能研究[D].西安:陜西科技大學(xué),2021.
GUO Xudong. Preparation and Performance of High solid Content Waterborne Polyurethane Based on Hydroxysulfonic Acid Hydrophilic Chain Extender[D]. Xi'an: Shaanxi University of Science and Technology, 2021.
[26]張淼.側(cè)鏈胺基型陽離子擴(kuò)鏈劑的合成及其合成水性聚氨酯的研究[D].合肥:安徽大學(xué),2020.
ZHANG Miao. Synthesis of Side Chain Amino Type Cationic Chain Extender and Study on Synthesis of Waterborne[D]. Hefei: Anhui university, 2020.
[27]葉青萱.親水基團(tuán)對水性聚氨酯性能的影響[J].聚氨酯工業(yè),2007,22(6):1-5.
YE Qingxuan. Effect of hydrophilic radicals on property of waterborne polyurethane[J]. Polyurethane industry, 2007, 22(6): 1-5.
[28]HONARKAR H, BARMAR M, BARIKANI M. Newsul-fonated waterborne wolyurethane dispersions: Preparation and characterization[J]. Journal of Dispersion Science and Technology, 2016, 37(8): 1219-1225.
[29]曾俊,王武生,阮德禮,等.DMBA與DMPA聚氨酯乳液主要性能比較[J].皮革化工,1999,16(5):19-22.
ZENG Jun, WANG Wusheng, RUAN Deli, et al. Comparison between main properties of polyurethane dispersions based on DMBA and DMPA [J]. Leather and Chemicals, 1999, 16(5): 19-22.
[30]Zhang Q Q, Lin X Q, Chen W S, et al. Applications of characterization methods in polyurethane materials: analysis of microphase-separated structures[J]. Applied Spectroscopy Reviews, 2022, 57(2): 153-176.
[31]薛振華.水性聚氨酯中不同二元醇結(jié)構(gòu)對性能的影響[D].濟(jì)南:齊魯工業(yè)大學(xué),2019.
XUE Zhenhua. A Thesis Submitted for the Application of the Master's Degree of Engineering[D]. Jinan: Qilu University of Technology, 2019.
[32]徐恒志.硬段含量和類型對水性聚氨酯性能的影響[D].合肥:安徽大學(xué),2012.
XU Hengzhi. Influence of Hard Segment Content and Type on the Performance of Waterborne Polyurethane[D]. Hefei: Anhui University, 2012.
[33]XIAO Y, ZHAO H B, WU B, et al. Preparation and characterization of waterborne polyurethane based on diphenylmethane diisocyanate-50[J]. Advances in Polymer Technology, 2018, 37(2): 596-605.
[34]王柯,彭婭,王燕.硬段含量對脂肪族陰離子水性聚氨酯性能的影響[J].化工進(jìn)展,2010,29(1):119-123.
WANG Ke, PENG Ya, WANG Yan. Effect of hard segment content on the properties of aliphatic anionic waterborne polyurethanes[J]. Chemical Industry and Engineering Progress, 2010, 29(1): 119-123.
[35]ORGILES-CALPENA E, ARAN-AIS F, TORRO-PALAU A M, et al. Influence of thechain extender nature on adhesives properties of polyurethane dispersions[J]. Journal of Dispersion Science and Technology, 2012, 33(1-3): 147-154.
[36]GARCIA P V, COLERA M, IWATA Y, et al. Incidence of the polyol nature in waterborne polyurethane dispersions on their performance as coatings on stainless steel[J]. Progress in Organic Coatings, 2013, 76(12): 1726-1729.
[37]LEE H T, WU S Y, JENG R J. Effects of sulfonated polyol on the properties of the resultant aqueous polyurethane dispersions[J]. Colloids and Surfaces a-Physicochemical and Engineering Aspects, 2006, 276(1-3): 176-185.
[38]LIU X H, HONG W, CHEN X D. Continuousproduction of water-borne polyurethanes: A Review[J]. Polymers, 2020, 12(12): 2875.
[39]HU L Q, PU Z J, ZHONG Y Q, et al. Effect of different carboxylic acid group contents on microstructure and properties of waterborne polyurethane dispersions[J]. Journal of Polymer Research, 2020, 27(5): 9.
[40]QIU F X, ZHANG J L, WU D M, et al. Waterborne polyurethane and modified polyurethane acrylate compo-sites[J]. Plastics Rubber and Composites, 2010, 39(10): 454-459.
[41]劉思彤.含氟丙烯酸酯/環(huán)氧樹脂復(fù)合改性水性聚氨酯的制備及性能研究[D].長春:長春工業(yè)大學(xué),2021.
LIU Sitong. Preparation and Properties of Waterborne Polyurethane Modified by Fluorinated Acrylate/Epoxy Resin Composite[D]. Changchun: Changchun University of Technology, 2021.
[42]王芳芳,錢年龍,商杭,等.硅改性疏水型水性聚氨酯的制備及性能研究[J].中國皮革,2021,50(5):55-63.
WANG Fangfang, QIAN Nianlong, SHANG Hang. Preparation and properties of silicon modified hydrophobic waterborne polyurethane[J]. China Leather, 2021, 50(5): 55-63.
[43]張曉靜.有機(jī)硅改性水性聚氨酯的制備及性能探究[D].杭州:浙江大學(xué),2021.
ZHANG Xiaojing. Preparation and Properties of Silicone Modified Waterborne Polyurethane[D]. Hangzhou: Zhejiang University, 2021.
[44]王雪.有機(jī)氟和交聯(lián)雙重改性水性聚氨酯的制備及性能研究[D].長春:長春工業(yè)大學(xué),2020.
WANG Xue. Study on the Preparation and Properties of Organic Fluorine and Crosslinked Double Modified Waterborne Polyurethane[D]. Changchun: Changchun University of Technology, 2020.
[45]LIM C H, CHOI H S, NOH S T. Surface modification with waterborne fluorinated anionic polyurethane disper-sions[J]. Journal of Applied Polymer Science, 2002, 86(13): 3322-3330.
[46]蘭芬芬.聚氨酯改性水性環(huán)氧樹脂及其在防腐涂料中的應(yīng)用[D].合肥:安徽大學(xué),2021.
LAN Fenfen. Polyurethane Modified Waterborne Epoxy Resin and Its Application in Anticorrosive Coatings[D]. Hefei: Anhui university, 2021.
[47]趙明恩.合成革用水性聚氨酯/環(huán)氧樹脂/丙烯酸酯IPN結(jié)構(gòu)構(gòu)筑及性能研究[D].青島:青島科技大學(xué),2019.
ZHAO Ming'en. Structuralconstruction and Properties of Waterborne Polyurethane/Epoxy Resin/Acrylate IPN for Synthetic Leather[D]. Qingdao: Qingdao University of Science and Technology, 2019.
[48]丁曉丹.納米SiO2改性水性聚氨酯的制備及性能研究[D].長春:長春工業(yè)大學(xué),2020.
DING Xiaodan. Study on Preparation and Properties of Waterborne Polyurethane Modified Polyurethane by Nano-SiO2[D]. Changchun: Changchun University of Tech-nology, 2020.
[49]宋永華.水性聚氨酯基納米復(fù)合材料的制備及其性能研究[D].西安:西安理工大學(xué),2021.
SONG Yongha. Preparation and Properties of Waterborne Polyurethane-Based Nanocomposites[D]. Xi'an: Xi'an University of Technology, 2021.
[50]WU G F, LI Y C, YANG Z H, et al. Preparation andcharacterization of glucose and sulfamate double-modified biodegradable waterborne polyurethane[J]. Chemistryselect, 2021, 6(31): 8140-8149.
[51]TRAVINSKAYA T, SAVELYEV Y, MISHCHUK E. Waterborne polyurethane based starch containing materials: Preparation, properties and study of degradability[J]. Polymer Degradation and Stability, 2014, 101: 102-108.
[52]TRET'YAKOVA A E, SAFONOV V V, YUSINA A Y. Study of processes of dyeing polyurethane fibres by various classes of dyes[J]. Fibre Chemistry, 2013, 44(5):284-287.
[53]LEE S K, LEE H Y, KIM S D. Dyeing properties ofmixture of ultrafine nylon and polyurethane with different types of dye[J]. Fibers and Polymers, 2013, 14(12): 2020-2026.
[54]潘笑娟,王利民,楊柳波,等.超細(xì)PA/PU合成革用酸性染料的染色性能研究[J].染料與染色,2006,43(4):27-31,40.
PAN Xiaojuan, WANG Limin, YANG Liubo, et al. A Study on dyeing properties of superfine fiber PA/PU syntheticleather[J]. Dyestuffs and Coloration, 2006, 43(4): 27-31, 40.
[55]胡雪麗,馬興元,郭夢亞,等.固色劑SLA在超細(xì)纖維合成革染色中的應(yīng)用研究[J].中國皮革,2014,43(23):24-27.
HU Xueli, MA Xingyuan, GUO Mengya, et al. Appli-cation of fixing agent SLA in microfiber synthetic leather dyeing[J]. China Leather, 2014, 43(23): 24-27.
[56]李崢嶸,涂偉萍,賴應(yīng)光,等.超細(xì)錦綸PU革增深勻染劑IntratexLPUA[J].印染,2010,36(21):27-29.
LI Zhengrong, TU Weiping, LAI Yingguang, et al. Deepening and leveling agent intratex LPUA for supermicro PA/PU leatheroid [J]. China Dyeing & Finishing, 2010, 36(21): 27-29.
[57]白剛,劉艷春.苯甲醇對超細(xì)纖維合成革染色性能的影響[J].紡織學(xué)報,2011,32(1):78-81.
BAI Gang, LIU Yanchun. Effect of benzoic alcohol on dyeing properties of microfiber synthetic leather[J]. Journal of Textile Research, 2011, 32(1): 78-81.
[58]李金華,李曉霞,張悅.超纖錦綸PU合成革的涂料染色工藝研究[J].皮革與化工,2014,31(5):28-30.
LI Jinhua, LI Xiaoxiao, ZHANG Yue. Research on pigment dyeing process for microfiber Nylon PU synthetic leather[J]. Leather and Chemicals, 2014, 31(5): 28-30.
[59]胡忠杰.超纖染色牢度的工藝優(yōu)化[J].印染,2018,44(15):32-34.
HU Zhongjie. Process optimization for improving color fastness of microfiber leather[J]. China Dyeing & Finishing, 2018, 44(15): 32-34.
[60]強(qiáng)濤濤,王曉芹,王學(xué)川,等.水解膠原蛋白對超細(xì)纖維合成革基布染色性能影響的研究[J].功能材料,2014,45(14):14066-14071.
QIANG Taotao, WANG Xiaoqin, WANG Xuechuan, et al. Study on the effect of dyeing properties of microfiber synthetic leather base by hydrolyzed collagen[J]. Journal of Functional Materials, 2014, 45(14): 14066-14071.
[61]龔燕燕,吉婉麗,徐欣欣,等.易染色超細(xì)纖維合成革用聚氨酯樹脂的研制[J].聚氨酯工業(yè),2007,22(4):34-37.
GONG Yanyan, JI Wanli, XU Xinxin, et al. Study on the preparation of polyurethane resin applied in superfine synthetic leather[J]. Polyurethane Industry, 2007, 22(4): 34-37.
[62]張衛(wèi)東.易染色超細(xì)纖維合成革用聚氨酯樹脂的合成與表征[D].上海:華東理工大學(xué),2012.
ZHANG Weidong. Preparation and Characterization of Easy Dying Polyurethane for Micro Fiber Leather[D]. Shanghai: East China University of Science and Technology, 2012.
[63]黃玲,成松濤,符曉蘭.殼聚糖/乙二醛交聯(lián)體系對超細(xì)纖維合成革染色性能的影響[J].陜西科技大學(xué)學(xué)報(自然科學(xué)版),2010,28(4):52-55.
HUANG Ling, CHEN Songtao, FU Xiaolan. Influence of chitosan-glyoxal cross-link on performance of dyeing in superfine fiber synthetic leather[J]. Journal of Shaanxi University of Science and Technology (Natural Science Edition), 2010, 28(4): 52-55.
[64]祝彬.超細(xì)纖維合成革用水性聚氨酯的研究進(jìn)展[J].中國皮革,2020,49(4):32-36.
ZHU Bin. Research progress of waterborne polyurethane for superfine fiber synthetic leather[J]. China Leather, 2020, 49(4): 32-36
[65]ZHENG Y, ZHANG X Y, LI J P. Synthesis and photochromism properties of anionic waterborne polyure-thane containing azobenzene chromophores[J]. Journal of Macromolecular Science Part a-Pure and Applied Chemi-stry, 2015, 52(11): 942-949.
[66]ZHAO J, HOU J H, CHAI C P, et al. Preparation and characterization of yellow waterborne polyurethane with 2,6-diaminoanthraquinone structure[J]. Polymer Testing, 2022, 106: 107451.
[67]WANG Y L, JIN L Q. Preparation andcharacterization of self-colored waterborne polyurethane and its application in eco-friendly manufacturing of microfiber synthetic leather base[J]. Polymers, 2018, 10(3): 289.
[68]WANG H H, TZAI G M, CHANG C C. Alkali reduction and reactive dye dyeing of T/N nonwoven fabrics dipped into silicon-containing, water-borne polyurethane[J]. Journal of Applied Polymer Science, 2005, 96(6): 2324-2335.
[69]LIU R W, CHEN Y, FAN H J. Design,characterization, dyeing properties, and application of acid-dyeable polyure-thane in the manufacture of microfiber synthetic eather[J]. Fibers and Polymers, 2015, 16(9): 1970-1980.
Abstract: With the shortage of natural leather resources and the continuous development of synthetic leather products, synthetic leather products have a wider application prospect on home furnishing, automotive decoration and other aspects. Microfiber synthetic leather is the most closely imitated product to natural leather. Although its physical and chemical properties are comparable to those of natural leather, its moisture permeability and dyeing properties are still far behind those of natural leather. Solvent-based polyurethane synthetic leather has been gradually replaced by environmental-friendly waterborne polyurethane due to the use of a lot of organic solvents in the production process.
Polyurethane is a kind of block copolymer with alternating hard and soft segments. The hard segments are mainly composed of isocyanates and small molecular chain extenders, which are easy to form hydrogen bonds, so that the polymer has fair rigidity and shows good tensile strength and elastic recovery force. The soft segments are mainly composed of polyester type or polyether type polyols, which are easily to form amorphous region, so that the polymer shows excellent flexibility. Compared with solvent-based polyurethane, hydrophilic monomers with carboxylic acid groups or sulfonic acid groups are introduced into the molecular structure during the polymerization of water-based polyurethane, which can make the product self-emulsified in water and effectively reduce the use of organic solvents. However, due to the introduction of hydrophilic monomer into the polymer chains, the mechanical properties and dyeing properties of waterborne polyurethane are significantly different from those of solvent-based polyurethane.
In the structure of waterborne polyurethane, the composition of soft and hard segments and the type and content of hydrophilic monomers would affect the degree of microphase separation, which have certain influence on its mechanical properties such as elongation at break and tensile strength. The dyeing properties and application properties can be effectively improved by regulating its composition and structure.
The difference of dyeing properties between microfiber and polyurethane leads to poor levelness and penetration of microfiber synthetic leather in the dyeing process. For the solvent-based polyurethane microfiber leather,the current dyeing methods and technological conditions can meet the market demand. But because of the introduction of hydrophilic groups in the macromolecules, the microstructure and packing state of waterborne polyurethane are different from those of solvent-based polyurethane, and the adsorption and diffusion behavior of dyes of the waterborne polyurethane microfiber leather has been changed. Although there are some studies on preparing the microfiber synthetic leather with colored waterborne polyurethanes, the dyeing mechanism and dyeing properties of the waterborne polyurethane microfiber leather are still few.
Keywords: waterborne polyurethane; hydrophilic group; composition and structure; mechanical property; the microfiber synthetic leather; dyeing