施強(qiáng) 任春穎 石教學(xué) 鄭雄 張須臻
摘 要:為實(shí)現(xiàn)一次浸膠滌綸工業(yè)絲與橡膠間界面粘合強(qiáng)度的可控增強(qiáng),在活化油劑中添加封端異氰酸酯,在橡膠的硫化過(guò)程中同步完成活化粘合。研究了活化油劑乳液質(zhì)量分?jǐn)?shù)、封端異氰酸酯添加量和活化工藝對(duì)滌綸工業(yè)絲/橡膠粘合性能的影響。結(jié)果表明:當(dāng)活化油劑乳液質(zhì)量分?jǐn)?shù)為5%、封端異氰酸酯質(zhì)量分?jǐn)?shù)為2%時(shí),滌綸工業(yè)絲表面間苯二酚-甲醛-膠乳(RFL)附著牢度、復(fù)合橡膠的H-抽出力與剝離強(qiáng)度達(dá)到最高;而隨活化溫度和活化時(shí)間的增加,H-抽出力先增大后減小。本文滌綸工業(yè)絲/橡膠的H-抽出力達(dá)21.1 N,接近常規(guī)一次浸膠樣品的2倍,顯著縮小了與二次浸膠樣品(H-抽出力27 N)的差距。相較于市場(chǎng)同類產(chǎn)品,含異氰酸酯活化油劑處理后滌綸工業(yè)絲/橡膠的H-抽出力和滌綸簾子線尺寸穩(wěn)定性明顯改善。
關(guān)鍵詞:滌綸工業(yè)絲;活化油劑;封端異氰酸酯;H-抽出力;剝離強(qiáng)度;尺寸穩(wěn)定性
中圖分類號(hào):TQ330.6+8
文獻(xiàn)標(biāo)志碼:A
文章編號(hào):1009-265X(2023)03-0163-09
基金項(xiàng)目:紹興市“揭榜掛帥”制科技項(xiàng)目(2021B41002)
作者簡(jiǎn)介:施強(qiáng)(1997—),男,安徽池州人,碩士研究生,主要從事滌綸工業(yè)絲的改性與應(yīng)用方面的研究。
通信作者:張須臻,E-mail:donghuaihe@163.com
簾子線的制備是滌綸工業(yè)絲的重要應(yīng)用之一[1]。當(dāng)前,滌綸工業(yè)絲與橡膠膠體之間的粘合[2-3]以二次浸膠法[4]和一次浸膠法[5]為主,其中二次浸膠法是通過(guò)對(duì)膠乳預(yù)處理后的滌綸工業(yè)絲進(jìn)行間苯二酚-甲醛-膠乳(RFL)二次上膠,然后與橡膠膠體復(fù)合的方法;而一次浸膠法是指纖維在紡絲過(guò)程中用活化油劑[6]上油,無(wú)需膠乳處理即可進(jìn)行RFL上膠、橡膠基體復(fù)合。與二次浸膠法相比,一次浸膠法具有工藝流程短,節(jié)能降耗的優(yōu)勢(shì),但相對(duì)于二次浸膠的增強(qiáng)橡膠,粘結(jié)強(qiáng)度較低。樓巧航等[4]研究同類纖維二次浸膠法,所得樣品H-抽出力為27 N,而一次浸膠法所得樣品的H-抽出力僅在14 N左右。如何有效提升一次浸膠法滌綸工業(yè)絲與橡膠膠體間的粘合強(qiáng)度,是目前行業(yè)內(nèi)亟待解決的問(wèn)題[7]。
為解決上述問(wèn)題,研究人員做了大量的研究。李華峰[8]研制出了改性間苯二酚-甲醛樹(shù)脂RF90,并將其用于185/60R14轎車子午線輪胎的制備,提高了簾線/橡膠的H-抽出力,但H-抽出力提升較小,僅提升了5.45%。Zhang等[9]合成出一種用于滌綸工業(yè)絲浸漬處理的新型間苯二酚無(wú)甲醛環(huán)保增黏劑來(lái)代替RFL中的有毒成分,改善了產(chǎn)品的綠色環(huán)保性能,但改性聚酯織物與橡膠之間的剝離粘合強(qiáng)度為17 N/mm,與未改性時(shí)相當(dāng)。此外,對(duì)滌綸工業(yè)絲的表面處理也是提高粘附性的重要改性方法,Luo等[10]用等離子體聚合涂層對(duì)滌綸工業(yè)絲表面進(jìn)行處理,顯著提高了簾線/橡膠的粘附性,但操作工藝繁瑣、加工成本高?,F(xiàn)在,關(guān)于異氰酸酯改性簾線與橡膠粘合強(qiáng)度的研究,主要是在二次浸膠法的基礎(chǔ)上,向預(yù)浸膠液中加入封端異氰酸酯,通過(guò)促進(jìn)預(yù)浸液層內(nèi)部及預(yù)浸液層與外層RFL膠乳間的粘合,改善簾線與橡膠的粘合性[4]。另外還可通過(guò)紫外線對(duì)PET進(jìn)行照射進(jìn)行物理活化,再將亞甲基二苯基二異氰酸酯(MDI)與PET進(jìn)行反應(yīng),最后直接與橡膠進(jìn)行復(fù)合,以此增強(qiáng)滌綸工業(yè)絲與橡膠的粘合強(qiáng)度[11]。然而,前者存在PET組分無(wú)法產(chǎn)生有效反應(yīng)性粘結(jié),粘結(jié)強(qiáng)度提升幅度有限的問(wèn)題;而后者工藝流程復(fù)雜,且紫外輻射極易引發(fā)PET裂解,降低工業(yè)絲的原有強(qiáng)度。為此,本文基于一次浸膠法,選擇封端的異氰酸酯對(duì)活化油劑進(jìn)行改性,通過(guò)可控?zé)崽幚砘罨惽杷狨ソM分,使活化后的異氰酸酯與RFL層及PET端羥基進(jìn)行反應(yīng),以解決滌綸工業(yè)絲與RFL膠乳層界面間黏附力的問(wèn)題。
1 實(shí) 驗(yàn)
1.1 實(shí)驗(yàn)原料
HMLS滌綸工業(yè)絲(1110 dtex/192f)、活化油劑,浙江古纖道綠色纖維有限公司;封端異氰酸酯,煙臺(tái)萬(wàn)華聚氨酯股份有限公司;RFL浸膠液、橡膠,新鄉(xiāng)市鼎誠(chéng)橡塑有限公司。橡膠的組分配置如表1所示。
1.2 儀器與設(shè)備
平板硫化(GT-7014-H50C),高鐵檢測(cè)儀器(東莞)有限公司;萬(wàn)能實(shí)驗(yàn)機(jī)(5843),美國(guó)INSTRON公司;真空干燥箱(DZF-6050),上海精宏實(shí)驗(yàn)設(shè)備有限公司;分析天平(AB265-S),瑞士METTLE TOLEDO公司;模具,揚(yáng)州市精卓試驗(yàn)機(jī)械廠;WIFI數(shù)顯顯微鏡(1000X),奧地利蘭精公司;熱空氣收縮檢測(cè)儀(TST2),上海戰(zhàn)晟機(jī)電設(shè)備有限公司。
1.3 實(shí)驗(yàn)方法
1.3.1 滌綸工業(yè)絲浸膠簾子線的制備
a)活化油劑(未加封端異氰酸酯)改性樣品:分別配置活化油劑水溶液,其中乳液質(zhì)量分?jǐn)?shù)為5%、10%、15%、20%,對(duì)滌綸工業(yè)絲進(jìn)行上油操作,保持絲束運(yùn)動(dòng)速度為10 cm/s。將上油后的滌綸工業(yè)絲束置于真空烘箱中干燥24 h,干燥溫度為60℃。將干燥上油絲進(jìn)行RFL乳液浸膠處理,浸膠時(shí)拉絲速度為10 cm/s,再放入60℃真空烘箱再次干燥24 h,制得滌綸工業(yè)絲浸膠簾子線。
b)封端異氰酸酯改性樣品:選取乳液質(zhì)量分?jǐn)?shù)為5%的活化油劑,分別配置含不同封端異氰酸酯質(zhì)量分?jǐn)?shù)的活化油劑,其中封端異氰酸酯質(zhì)量分?jǐn)?shù)為1%、2%、3%、4%,后續(xù)上油、浸膠與干燥操作與 a)樣品的制備相同。
1.3.2 滌綸工業(yè)絲/橡膠復(fù)合樣品的制備
根據(jù)國(guó)家標(biāo)準(zhǔn)GB/T 2942—2009《硫化橡膠與纖維簾線靜態(tài)粘合強(qiáng)度的測(cè)定 H抽出法》,將5 mm厚橡膠片剪成條狀后,填入上下模具的凹槽中,嵌入滌綸簾子線,纖維的一端固定在模具上,另一端則以砝碼賦予張力(載荷為50 g),然后合并上下模具,放入平板硫化儀中進(jìn)行熱壓硫化處理,同時(shí)引發(fā)封端異氰酸酯活化反應(yīng)。熱壓硫化參數(shù)設(shè)置為:循環(huán)排氣5次;預(yù)熱時(shí)間5 min;上下模溫度140℃;硫化壓力5 MPa;硫化時(shí)間30 min;冷卻溫度20℃。模具與H型試樣的示意圖如圖1所示。樣品在復(fù)合過(guò)程中,解封后產(chǎn)生高反應(yīng)活性的異氰酸酯基團(tuán)會(huì)與滌綸工業(yè)絲、RFL中的活性基團(tuán)發(fā)生反應(yīng)以增強(qiáng)滌綸工業(yè)絲與RFL層的粘合性,來(lái)達(dá)到增強(qiáng)粘合性能的目的[12]。封端異氰酸酯的改性原理示意如圖2所示。從圖2中可以看出,解封后活化油劑層的異氰酸酯基團(tuán)會(huì)與滌綸工業(yè)絲端羥基發(fā)生反應(yīng),并且反應(yīng)活性較強(qiáng)的異氰酸酯基團(tuán)也會(huì)與RFL膠乳層中的氨基、環(huán)氧基團(tuán)等發(fā)生反應(yīng),而RFL層中的膠乳則與橡膠中的不飽和鍵硫化時(shí)發(fā)生交聯(lián),使RFL與橡膠粘合更緊密。
1.3.3 撕裂測(cè)試用滌綸工業(yè)絲/橡膠復(fù)合樣品的制備
將滌綸工業(yè)絲簾子線往復(fù)平鋪在鐵板上,一端固定,另一端以50 cN載荷賦予張力,如圖3所示。在平鋪的簾線一端放入固定膠片,膠片上覆蓋隔離用耐熱塑料紙,然后放入混煉膠片,最后再在最上層覆蓋墊布。根據(jù)上述硫化工藝對(duì)試樣進(jìn)行硫化處理,硫化結(jié)束后立即取出樣品進(jìn)行冷卻。
1.4 測(cè)試方法
1.4.1 浸膠層附著牢度
將不同浸膠的簾線樣品分別用膠帶粘撕20次和50次,通過(guò)損失的質(zhì)量與初始質(zhì)量的比值計(jì)算質(zhì)量損失率,以表征浸膠層在纖維表面的附著牢度。
1.4.2 H-抽出力
根據(jù)國(guó)標(biāo)GB/T 2942—2009《硫化橡膠與纖維簾線靜態(tài)粘合強(qiáng)度的測(cè)定 H抽出法》,在萬(wàn)能實(shí)驗(yàn)機(jī)上對(duì)滌綸工業(yè)絲與橡膠復(fù)合材料進(jìn)行H-抽出力的測(cè)試。抽出速度為100 mm/min,每組樣品測(cè)試8次求平均值,單位為N。
1.4.3 表面形貌
通過(guò)WIFI數(shù)顯光學(xué)顯微鏡對(duì)剝離橡膠和H-抽出后的簾子線表面形貌進(jìn)行觀察,通過(guò)觀測(cè)圖像比較簾子線表面橡膠的附著量。
1.4.4 干熱收縮率
通過(guò)熱空氣收縮儀對(duì)未改性、活化油劑改性和異氰酸酯改性的滌綸簾子線作熱收縮率的測(cè)試。測(cè)試溫度:177℃;測(cè)試時(shí)間:10 min;預(yù)加張力:0.088 cN/dtex。
1.4.5 簾子線/橡膠界面剝離強(qiáng)度測(cè)試
根據(jù)國(guó)標(biāo)GB/T 40725—2021《浸膠簾線與橡膠粘合剝離性能試驗(yàn)方法》在萬(wàn)能實(shí)驗(yàn)機(jī)上進(jìn)行簾子線與橡膠間的界面撕裂實(shí)驗(yàn)。將寬度為25 mm的試樣固定在夾持器上,其中固定夾持器夾住混煉膠層,移動(dòng)的夾持器夾住帶有固定橡膠的滌綸簾線,保持剝離角度180°,夾具運(yùn)動(dòng)速率為100 mm/min。最后以實(shí)驗(yàn)得到的最大剝離力與滌綸簾線的束數(shù)之比為單束簾線的剝離力,取兩個(gè)試樣的算數(shù)平均值作為實(shí)驗(yàn)結(jié)果,單位為單束剝離力/N。
2 結(jié)果與討論
2.1 各因素的正交實(shí)驗(yàn)分析
對(duì)活化油劑乳液質(zhì)量分?jǐn)?shù)、活化時(shí)間、活化溫度以及封端異氰酸酯質(zhì)量分?jǐn)?shù)四大因素的正交實(shí)驗(yàn)分析如表2所示。通過(guò)極差分析可得對(duì)H-抽出力影響從大到小的順序依次為:封端異氰酸酯質(zhì)量分?jǐn)?shù)、活化溫度、活化時(shí)間、活化油劑乳液質(zhì)量分?jǐn)?shù)。
2.2 活化油劑乳液質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲/橡膠粘合力的影響
2.2.1 活化油劑乳液質(zhì)量分?jǐn)?shù)對(duì)簾子線表層RFL膠乳附著牢度的影響
在加工過(guò)程中,上油是纖維后處理加工的第一步,因此確定合適的活化油劑上油量是后續(xù)探討封端異氰酸酯質(zhì)量分?jǐn)?shù)、活化條件的前提條件。在討論封端異氰酸酯質(zhì)量分?jǐn)?shù)、活化條件前,首先對(duì)活化油劑(不含異氰酸酯)添加量進(jìn)行了探索實(shí)驗(yàn)。滌綸工業(yè)絲中活化油劑乳液質(zhì)量分?jǐn)?shù)對(duì)其表層RFL膠乳附著牢度的影響如圖4所示。由圖4中可知,大部分樣品隨著剝離次數(shù)從20次增加至50次,其RFL膠乳附著層質(zhì)量損失明顯加劇,而活化油劑乳液質(zhì)量分?jǐn)?shù)為5%和10%的兩組樣品質(zhì)量損失隨剝離次數(shù)的增加未有改變,表明該兩組樣品的RFL膠乳在滌綸工業(yè)絲表面的附著牢度較好。與10%活化油劑的滌綸工業(yè)絲相比,5%活化油劑的滌綸工業(yè)絲的質(zhì)量損失較低,表明在該條件下滌綸工業(yè)絲與RFL膠乳有著較好的復(fù)合效果。
2.2.2 活化油劑乳液質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲/橡膠H-抽出力的影響
滌綸工業(yè)絲中活化油劑乳液質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲/橡膠H-抽出力的影響(未加封端異氰酸酯,活化時(shí)間為0.5 h,活化溫度為140℃)如圖5所示。隨著活化油劑乳液質(zhì)量分?jǐn)?shù)的增加,復(fù)合樣品的H-抽出力先增大后減小的趨勢(shì),當(dāng)活化油劑乳液質(zhì)量分?jǐn)?shù)為5%時(shí)達(dá)到極大值12.9 N。隨著乳液質(zhì)量分?jǐn)?shù)進(jìn)一步增大,H-抽出力穩(wěn)定在10.5~11.5 N的范圍內(nèi),這表明滌綸工業(yè)絲表面以乳液質(zhì)量分?jǐn)?shù)為5%活化油劑上油較為合理,較高的活化油劑乳液質(zhì)量分?jǐn)?shù)反而降低滌綸工業(yè)絲與橡膠的粘合性。
2.3 封端異氰酸酯對(duì)滌綸工業(yè)絲/橡膠粘合力的影響
2.3.1 異氰酸酯質(zhì)量分?jǐn)?shù)對(duì)簾子線表層RFL膠乳附著牢度的影響
在5%活化油劑中異氰酸酯質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲簾子線表層RFL膠乳附著牢度的影響如圖6所示。由圖6中可知,隨著剝離次數(shù)從20次增加至50次,簾子線表面RFL膠乳附著層出現(xiàn)不同程度的質(zhì)量損失。隨封端異氰酸酯質(zhì)量分?jǐn)?shù)的增加,RFL膠乳附著層質(zhì)量損失先減小后增大。其中含2%封端異氰酸酯的滌綸工業(yè)絲的質(zhì)量損失較低,表明在該條件下,異氰酸酯改善滌綸工業(yè)絲與RFL膠乳間界面結(jié)合力的效果較好。值得注意的是,隨異氰酸酯質(zhì)量分?jǐn)?shù)進(jìn)一步增大,RFL膠乳含量被剝離程度持續(xù)加劇,說(shuō)明過(guò)量的異氰酸酯會(huì)削弱滌綸工業(yè)絲與RFL膠乳間界面結(jié)合力。這種現(xiàn)象可能是由于與RFL及PET端基中的活性基團(tuán)反應(yīng)徹底,多余的異氰酸酯與空氣中的活性成分如水等發(fā)生反應(yīng),形成性能穩(wěn)定的低聚物組分[13]。該低聚物組分摻雜于RFL與簾線界面層中,導(dǎo)致界面結(jié)合力降低。
2.3.2 異氰酸酯質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲/橡膠剝離強(qiáng)度的影響
5%活化油劑中封端異氰酸酯質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲/橡膠剝離力的影響(活化時(shí)間為1 h,活化溫度為140℃)如圖7所示。由圖7可知,在0%~2%封端異氰酸酯質(zhì)量分?jǐn)?shù)的區(qū)間中,滌綸工業(yè)絲/橡膠剝離力出現(xiàn)上升趨勢(shì),而在2%質(zhì)量分?jǐn)?shù)后樣品的剝離力出現(xiàn)明顯的下降趨勢(shì),其中在2%時(shí)達(dá)到單束最大剝離力1.37 N,相較于無(wú)封端異氰酸酯的樣品提升了14%,表明5%活化油劑(含2%封端異氰酸酯)處理的工業(yè)絲與橡膠的粘合性較好。該結(jié)果與上述圖6中簾子線表層RFL膠乳附著牢度結(jié)論相一致,表明簾子線表層RFL膠乳附著牢度密切影響滌綸工業(yè)絲與橡膠基體之間的粘合強(qiáng)度。
2.3.3 異氰酸酯質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲/橡膠H-抽出力的影響
在5%活化油劑中封端異氰酸酯質(zhì)量分?jǐn)?shù)對(duì)滌綸工業(yè)絲/橡膠H-抽出力的影響(活化時(shí)間為1 h,活化溫度為140℃)如圖8所示。從圖8中可以看出,隨封端異氰酸酯質(zhì)量分?jǐn)?shù)的增加,樣品H-抽出力出現(xiàn)先增大后降低的趨勢(shì),與圖7中所呈現(xiàn)的滌綸工業(yè)絲/橡膠剝離力變化趨勢(shì)相似。曲線兩端0%和4%質(zhì)量分?jǐn)?shù)封端異氰酸酯的滌綸工業(yè)絲/橡膠樣品H-抽出力明顯較低,當(dāng)封端異氰酸酯質(zhì)量分?jǐn)?shù)為2%時(shí),樣品的H-抽出力達(dá)到極大值21.1 N。該現(xiàn)象表明,當(dāng)質(zhì)量分?jǐn)?shù)為2%時(shí),封端異氰酸酯經(jīng)活化能夠與滌綸工業(yè)絲和RFL膠乳層發(fā)生良好的反應(yīng)性結(jié)合;而當(dāng)其質(zhì)量分?jǐn)?shù)進(jìn)一步增大時(shí),過(guò)量的封端異氰酸酯難以發(fā)生有效反應(yīng),弱化滌綸工業(yè)絲/橡膠基體間的粘合效果[12]。
2.3.4 異氰酸酯改性對(duì)滌綸簾子線尺寸穩(wěn)定性的影響
改性的滌綸簾子線與市面上其他滌綸簾子線的熱收縮率和定負(fù)荷伸長(zhǎng)率的比較[14] ,如表3所示。其中樣品1—3分別為未改性、活化油劑改性以及異氰酸酯改性的滌綸簾子線;樣品4—7為市面上的各類滌綸簾子線,分別為國(guó)產(chǎn)標(biāo)準(zhǔn)型、1W70型、日本HMLS型和荷蘭1125T型滌綸簾子線??梢钥闯龌罨蛣┖彤惽杷狨ジ男詴?huì)使滌綸簾子線的熱收縮率和定負(fù)荷伸長(zhǎng)率提升,尺寸穩(wěn)定性略微下降。而改性后的滌綸簾子線比國(guó)產(chǎn)標(biāo)準(zhǔn)型、1W70型和荷蘭1125T型熱收縮率要低;改性后的滌綸簾子線要比1W70型和日本HMLS型定負(fù)荷伸長(zhǎng)率要低,表明異氰酸酯改性的滌綸簾子線尺寸穩(wěn)定性能得到較好地保持。
2.3.5 異氰酸酯改性對(duì)滌綸工業(yè)絲與橡膠粘合界面的影響
未改性的原絲、只含活化油劑改性的工業(yè)絲以及含異氰酸酯改性的滌綸工業(yè)絲剝離橡膠后的表面粘附形貌如圖9所示,其中界面中深色區(qū)域(類似圈出來(lái)的部分)為剝離后工業(yè)絲粘附的橡膠組分。從圖9中可以看出,滌綸工業(yè)絲表面橡膠附著量依次增加,表明活化油劑和異氰酸酯的改性增強(qiáng)了滌綸工業(yè)絲與橡膠的粘附性,也與以上結(jié)論相對(duì)應(yīng)。
不同條件處理的滌綸工業(yè)絲與橡膠H-抽出后工業(yè)絲表面的粘附情況如圖10所示。這與剝離后工業(yè)絲表面粘附情況相似,進(jìn)一步表明活化油劑和異氰酸酯的改性都增強(qiáng)了滌綸工業(yè)絲與橡膠的粘附性。
2.4 活化工藝對(duì)滌綸工業(yè)絲/橡膠粘合力的影響
2.4.1 活化溫度對(duì)滌綸工業(yè)絲/橡膠H-抽出力的影響
用5%活化油劑乳液(含2%封端異氰酸酯)處理的滌綸工業(yè)絲在不同溫度(130~155℃)下與橡膠復(fù)合(活化時(shí)間為1 h)所制得樣品H-抽出力的變化如圖11所示。隨著活化溫度的升高,復(fù)合樣品的H-抽出力先增大后減小,在活化溫度為140℃時(shí)達(dá)到最大值,表現(xiàn)出良好的滌綸工業(yè)絲與橡膠間的界面粘合性能。該現(xiàn)象表明,封端異氰酸酯的解封端活性在140℃以下隨著處理溫度的升高而逐漸升高;當(dāng)溫度高于140℃時(shí),該解封端活性受到抑制。
2.4.2 活化時(shí)間對(duì)滌綸工業(yè)絲/橡膠H-抽出力的影響
以5%質(zhì)量分?jǐn)?shù)的活化油劑水溶液(含1%封端異氰酸酯)處理的滌綸工業(yè)絲在與橡膠在140℃活化溫度熱處理復(fù)合時(shí),活化時(shí)間對(duì)樣品H-抽出力的影響如圖12所示。從圖12中可以看出,在活化處理的前2 h內(nèi),增強(qiáng)橡膠的H-抽出力隨活化時(shí)間的延長(zhǎng)整體呈現(xiàn)上升趨勢(shì),但隨后出現(xiàn)高位波動(dòng)的變化。對(duì)于橡膠硫化規(guī)律而言,硫化(同時(shí)發(fā)生封端異氰酸酯活化)時(shí)間過(guò)長(zhǎng),可能會(huì)導(dǎo)致橡膠過(guò)硫化,進(jìn)而使得橡膠的斷裂強(qiáng)力降低[15]。綜合樣品H-抽出力和橡膠硫化后的力學(xué)性能,1~2 h應(yīng)為滌綸工業(yè)絲/橡膠體系合理的活化時(shí)間。
3 結(jié) 論
本文以規(guī)格為1110 dtex/192f的滌綸工業(yè)絲為基礎(chǔ)原料,在活化油劑中添加封端異氰酸酯對(duì)滌綸工業(yè)絲進(jìn)行上油,再通過(guò)一次浸膠滌綸工業(yè)絲,最后在與橡膠的復(fù)合的過(guò)程中同步完成活化粘合。研究了活化油劑乳液質(zhì)量分?jǐn)?shù)、異氰酸酯質(zhì)量分?jǐn)?shù)、活化條件對(duì)滌綸工業(yè)絲與橡膠之間粘附力以及滌綸簾子線尺寸穩(wěn)定性的影響,結(jié)論如下:
a)隨著封端異氰酸酯質(zhì)量分?jǐn)?shù)的增大,滌綸工業(yè)絲表面RFL膠乳附著牢度、滌綸工業(yè)絲復(fù)合橡膠的H-抽出力以及剝離強(qiáng)度均先增大后減小,并在封端異氰酸酯質(zhì)量分?jǐn)?shù)為2%時(shí)出現(xiàn)極大值(21.1 N),接近常規(guī)一次浸膠樣品的2倍,進(jìn)一步縮小了與二次浸膠法所得樣品(H-抽出力達(dá)27 N)的差距。此外,改性后,H-抽出力和尺寸穩(wěn)定性較市場(chǎng)上同類產(chǎn)品具有明顯優(yōu)勢(shì)。
b)隨著活化溫度的增加,滌綸工業(yè)絲/橡膠的H-抽出力先增大后減小,在140℃時(shí)到達(dá)峰值;通過(guò)對(duì)活化時(shí)間的研究表明,滌綸工業(yè)絲/橡膠體系合理的活化時(shí)間在1~2 h。
c)隨著活化油劑乳液質(zhì)量分?jǐn)?shù)的增加,RFL膠乳在滌綸工業(yè)絲表面的附著牢度先增后降,當(dāng)活化油劑乳液質(zhì)量分?jǐn)?shù)為5%時(shí)達(dá)到最大;滌綸工業(yè)絲/橡膠的H-抽出力也在活化油劑乳液質(zhì)量分?jǐn)?shù)為5%時(shí)達(dá)到極大值12.9 N,較原絲樣品(H-抽出力為11.2 N)提升較小。表明單純活化油劑對(duì)改性滌綸工業(yè)絲與橡膠粘合力的提升較小。所以,向活化油劑中添加封端異氰酸酯對(duì)滌綸工業(yè)絲進(jìn)行改性是有必要的。
參考文獻(xiàn):
[1]JI H, CHEN K, SONG M G, et al. Effect of flame retardant on the microfine structures and creep behavior of polyester industrial yarns[J]. The Journal of The Textile Institute, 2022, 113(2): 273-280.
[2]MOUSTAFA H, LAWANDY S N, RABEE M, et al. Effect of green modification of nanoclay on the adhesion behavior of EPDM rubber to polyester fabric[J]. International Journal of Adhesion and Adhesives, 2020, 100: 102617.
[3]HAN R J, SHAO Y R, QUAN X D, et al. Effects of titanate on the bonding properties of silicone rubber and polyester fabric[J]. Polymer Composites, 2021, 42(5): 2370-2379.
[4]樓巧航,韓建,丁新波,等.高模低縮滌綸簾子線二次浸膠工藝研究[J].浙江理工大學(xué)學(xué)報(bào),2012,29(6):823-826,832.
LOU Qiaohang, HAN Jian, DING Xinbo, et al. The two-step dipping process of HMLS PET cords[J]. Journal of Zhejiang Sci-Tech University, 2012, 29(6): 823-826, 832.
[5]許其軍,徐述科,季永中,等.用于一浴浸膠的粘合活化型滌綸工業(yè)絲的開(kāi)發(fā)[J].合成纖維,1998,27(5):45-48.
XU Qijun, XUShuke, JI Yongzhong, et al. Development of adhesive activated polyester industrial silk for one-bath dipping[J]. Synthetic Fiber in China, 1998, 27(5): 45-48.
[6]陳天陸,王鐘,薛淑云,等.油劑質(zhì)量分?jǐn)?shù)對(duì)高強(qiáng)低縮型聚酯活化絲性能的影響[J].現(xiàn)代絲綢科學(xué)與技術(shù),2020,35(4):4-6.
CHEN Tianlu, WANG Zhong, XUE Shuyun, et al.The effect of oil ratio on the properties of activated polyester filament with high modulus and low shrinkage[J]. Modern Silk Science & Technology, 2020, 35(4): 4-6.
[7]袁愛(ài)春,胡祖明,劉兆峰.滌綸簾子線與橡膠粘合性能的研究[J].產(chǎn)業(yè)用紡織品,2007,25(10):30-34.
YUAN Aichun, HU Zuming, LIU Zhaofeng. The research on the adhesion between PET cord and rubber[J]. Technical Textiles, 2007, 25(10): 30-34.
[8]李華峰.改性間苯二酚-甲醛樹(shù)脂RF90在轎車子午線輪胎帶束層膠中的應(yīng)用[J].橡膠科技,2014,12(12):38-40.
LI Huafeng. Application of modified resorcinol-formaldehyde resin RF90 in the belt compound of PCR tire[J]. Rubber Science and Technology, 2014, 12(12): 38-40.
[9]ZHANG B, CHEN S X, WANG W C, et al. Polyester (PET) fabrics coated with environmentally friendly adhesive and its interface structure and adhesive properties with rubber[J]. Composites Science and Technology, 2020, 195: 108171.
[10]LUO S J, VAN O W J, MADER E, et al. Surface modification of textile tire cords by plasma polymerization for improvement of rubber adhesion[J]. Rubber Chemistry and Technology, 2000, 73(1): 121-137.
[11]Razavizadeh M, Jamshidi M. Adhesion of nitrile rubber(NBR)to polyethylene terephthalate (PET) fabric. Part 1: PET surface modification by methylenediphenyl di-isocyanate (MDI)[J]. Applied Surface Science, 2016, 360: 429-435.
[12]許其軍,姚峻,程輝,等. 滌綸浸膠用封閉異氰酸酯的性能及應(yīng)用[J]. 產(chǎn)業(yè)用紡織品, 2002, 20(6): 37-39.
XU Qijun, YAO Jun, CHENG Hui,et al. Performance and application of blocked diisocyanate for polyester dipping[J]. Technical Textiles, 2002, 20(6): 37-39.
[13]WOLF M E, VANDEZANDE J E, SCHAEFER H F. Catalyzed reaction of isocyanates (RNCO) with water[J]. Physical Chemistry Chemical Physics, 2021, 23(34): 18535-18546.
[14]黃凱. 高模量低收縮聚酯工業(yè)絲和浸膠簾子布的工藝研究[D]. 蘇州:蘇州大學(xué), 2004.
HUANG Kai. Study on the Production Techniques of HMLS Polyester Industrial Yarn and Dipped Tire Cord Fabric[D]. Suzhou: Soochow University, 2004.
[15]WEI Y C, LIU G X, ZHANG H F, et al. Non-rubber components tuning mechanical properties of natural rubber from vulcanization kinetics[J]. Polymer, 2019, 183: 121911.
Abstract: In recent years, the demand for tires in China is increasing rapidly, in which radial tires are the main product. HMLS polyester industrial yarns have obvious advantages as the frame material of tire due to low cost, small elongation deformation, good dimensional stability, high modulus and low thermal shrinkage. However, the modulus and polarity of the HMLS polyester industrial yarn and rubber have great difference, leading to low interface adhesion, and a peeling failure. Therefore, it becomes an important research direction to enhance the bonding performance of the interface between the polyester industrial yarn and rubber.
In this paper, based on the existing conventional methods of preparing polyester cords by dipping polyester industrial yarns, the one-step dipping method is improved to make its performance close to that of the product by two-step dipping. In the two-step dipping method, resorcinol formaldehyde latex (RFL) is used to pretreat polyester industrial yarns and then compounded with rubber to achieve a high interface adhesion. While in the one-dip method, the yarn can be oiled with an activated oil agent during spinning, and RFL and rubber matrix compounding can be carried out without pre-treatment of polyester industrial yarns. Compared with the two-dip method, the one-dip method has the advantages of short process, energy saving and consumption reduction, but the bonding strength between the polyester industrial yarn and rubber is lower. In this paper, the blocked isocyanate is added to the activated oil agent and then oil is applied during spinning. The polyester industrial yarn is dipped in the one-dip method, and then compounded with rubber. During the subsequent vulcanization of rubber, the blocked isocyanate component is simultaneously activated by thermal effect to realize the interface reinforcement between the fiber and rubber. The effect of emulsion mass fraction of activating oil, amount of blocked isocyanate and activation technology on the interfacial adhesion between the polyester industrial yarn and rubber were systematically studied. The results show that, the adhesion fastness of RFL on the surface of the polyester industrial yarn increases at first and then decreases with the increase of emulsion mass fraction of activating oil. The maximum H-pull force of the polyester industrial yarn/rubber reaches its maximum value at an emulsion mass fraction of activating oil of 5%. With the increase of the blocked isocyanate content, the adhesion fastness of RFL on the surface of the polyester industrial yarn, the H-pull force and peeling strength of polyester industrial yarn/rubber increase at first and then decrease, and the maximum values are recorded at a blocked isocyanate content of 2%. With the increase of activation temperature or activation time, the H-pull force of polyester industrial yarn/rubber firstly increases and then decreases, and reaches the peak value at 140℃ or 2 h. The H-pull force of polyester industrial yarn/rubber treated with activating oil (containing isocyanate) is 21.1N, almost twice of the force for the similar samples obtained via the general one-dip method, and significantly reducing the difference with that of the two-dip treated samples (H-pull force 27 N). Compared with the similar commercial products, the H-pull force of polyester industrial yarn/rubber and the dimensional stability of polyester cord treated with activating oil containing isocyanates are significantly improved.
Based onthe one-dip method, the polyester industrial yarn is modified with activating oil (containing isocyanate) and contributes the adhesion between the polyester industrial yarn and rubber without affecting its dimensional stability. This study provides a new idea for the modification of polyester industrial yarns for cords, and also provides a reference for the modification of other tire frame materials.
Keywords: polyester industrial yarn; activating oil agent; blocked isocyanate; H-pull force; peel strength; dimensional stability