硅橡膠是指主鏈由硅和氧原子交替構成(cheng),硅原子上(shang)通常連有(you)兩個有(you)機基團的(de)(de)橡(xiang)(xiang)(xiang)膠(jiao)。普通的(de)(de)硅橡(xiang)(xiang)(xiang)膠(jiao)主要由含(han)甲基和少量乙(yi)烯基的(de)(de)硅氧鏈節組成(cheng)。苯(ben)基的(de)(de)引入(ru)可(ke)(ke)(ke)提高硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)耐(nai)(nai)高、低(di)溫(wen)(wen)性(xing)能(neng)(neng),三(san)氟丙基及氰基的(de)(de)引入(ru)則(ze)可(ke)(ke)(ke)提高硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)耐(nai)(nai)溫(wen)(wen)及耐(nai)(nai)油性(xing)能(neng)(neng)。硅橡(xiang)(xiang)(xiang)膠(jiao)耐(nai)(nai)低(di)溫(wen)(wen)性(xing)能(neng)(neng)良好,一(yi)般在-55℃下仍(reng)能(neng)(neng)工(gong)作(zuo)。引入(ru)苯(ben)基后(hou),可(ke)(ke)(ke)達-73℃。硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)耐(nai)(nai)熱性(xing)能(neng)(neng)也很突出(chu),在180℃下可(ke)(ke)(ke)長(chang)期工(gong)作(zuo),稍高于(yu)200℃也能(neng)(neng)承受數周或更長(chang)時間(jian)仍(reng)有(you)彈(dan)性(xing),瞬時可(ke)(ke)(ke)耐(nai)(nai)300℃以上(shang)的(de)(de)高溫(wen)(wen)。硅橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)透氣(qi)(qi)性(xing)好,氧氣(qi)(qi)透過(guo)率在合(he)成(cheng)聚合(he)物中是較高的(de)(de)。此外,硅橡(xiang)(xiang)(xiang)膠(jiao)還具(ju)有(you)生理(li)惰性(xing)、不會導致(zhi)凝血的(de)(de)突出(chu)特性(xing),因此在醫用領域(yu)應(ying)用廣(guang)泛。
主要品種
硅(gui)橡(xiang)膠(jiao)(jiao)分(fen)(fen)類(lei)的方法很多,通常按(an)固化前(qian)的形態分(fen)(fen)為(wei)固體(ti)硅(gui)橡(xiang)膠(jiao)(jiao)和液體(ti)硅(gui)橡(xiang)膠(jiao)(jiao);按(an)硫化溫(wen)度分(fen)(fen)為(wei)室溫(wen)硫化硅(gui)橡(xiang)膠(jiao)(jiao),高(gao)溫(wen)硫化硅(gui)橡(xiang)膠(jiao)(jiao);按(an)所用(yong)(yong)單體(ti)的不(bu)同,可(ke)分(fen)(fen)為(wei)甲(jia)基(ji)乙(yi)烯基(ji)硅(gui)橡(xiang)膠(jiao)(jiao),甲(jia)基(ji)苯(ben)基(ji)乙(yi)烯基(ji)硅(gui)橡(xiang)膠(jiao)(jiao)、氟硅(gui),腈硅(gui)橡(xiang)膠(jiao)(jiao)等(deng)(deng);按(an)性能(neng)和用(yong)(yong)途的不(bu)同又可(ke)分(fen)(fen)為(wei)通用(yong)(yong)型(xing)(xing)、超耐低溫(wen)型(xing)(xing)、超耐高(gao)溫(wen)型(xing)(xing)、高(gao)強力(li)型(xing)(xing)、耐油型(xing)(xing)、醫用(yong)(yong)型(xing)(xing)等(deng)(deng)等(deng)(deng)。
發展史
硅(gui)(gui)橡(xiang)膠(jiao)(jiao)早期是由美(mei)國(guo)以三氯(lv)化鐵為催化劑合(he)(he)成(cheng)(cheng)的(de)。1945年,硅(gui)(gui)橡(xiang)膠(jiao)(jiao)產品問世。1948年,采用高比(bi)表面積的(de)氣(qi)相法白炭黑補(bu)強的(de)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)研(yan)制(zhi)成(cheng)(cheng)功,使硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)性能躍升到實用階(jie)段,奠定了(le)現代硅(gui)(gui)橡(xiang)膠(jiao)(jiao)生產技術的(de)基(ji)礎。從(cong)二甲(jia)基(ji)二氯(lv)硅(gui)(gui)烷合(he)(he)成(cheng)(cheng)開始生產硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)國(guo)家(jia)有美(mei)國(guo)。俄(e)羅斯、德(de)國(guo)、日本、韓(han)國(guo)和中(zhong)國(guo)等。中(zhong)國(guo)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)工業化研(yan)究始于1957年,多家(jia)研(yan)究所(suo)和企業陸續開發出各(ge)種硅(gui)(gui)橡(xiang)膠(jiao)(jiao)。到2003年底,中(zhong)國(guo)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)生產能力為135千噸,其中(zhong)高溫膠(jiao)(jiao)100千噸。
高溫硫化硅橡膠
高溫(wen)硫(liu)(liu)(liu)化(hua)(hua)硅橡膠是(shi)(shi)(shi)指聚硅氧(yang)烷變成彈性體(ti)的過(guo)程是(shi)(shi)(shi)經過(guo)高溫(wen)(110-170℃)硫(liu)(liu)(liu)化(hua)(hua)成型的。它主(zhu)要以高分子量的聚甲基(ji)乙烯(xi)基(ji)硅氧(yang)烷為生膠,混入補(bu)強(qiang)(qiang)填料、硫(liu)(liu)(liu)化(hua)(hua)劑等,在加(jia)熱加(jia)壓下(xia)硫(liu)(liu)(liu)化(hua)(hua)成彈性體(ti)。硅橡膠的補(bu)強(qiang)(qiang)主(zhu)要是(shi)(shi)(shi)各(ge)種類型的白炭黑,可(ke)使(shi)硫(liu)(liu)(liu)化(hua)(hua)膠的強(qiang)(qiang)度增(zeng)加(jia)數(shu)十倍。有(you)時(shi)為了降低成本或改善膠料性能(neng)及賦予(yu)硫(liu)(liu)(liu)化(hua)(hua)膠各(ge)種特殊的性能(neng),也加(jia)入相應的各(ge)種添(tian)加(jia)劑。硫(liu)(liu)(liu)化(hua)(hua)劑是(shi)(shi)(shi)各(ge)種有(you)機過(guo)氧(yang)化(hua)(hua)物(wu)或加(jia)成反(fan)應催(cui)化(hua)(hua)劑。
加工成型方法如圖所示。一次(ci)硫化(hua)的(de)(de)目的(de)(de)是進行高分(fen)子鏈的(de)(de)交(jiao)聯(lian)反應;二次(ci)硫化(hua)的(de)(de)目的(de)(de)是進行補充交(jiao)聯(lian)、驅除硫化(hua)劑分(fen)解產物和(he)其他揮發性化(hua)合物以穩定硫化(hua)膠(jiao)的(de)(de)各項性能。常用的(de)(de)設備有(you)開(kai)放式煉(lian)(lian)膠(jiao)機(ji)(ji)、捏合機(ji)(ji)及(ji)真(zhen)空(kong)密煉(lian)(lian)機(ji)(ji)。
主要性能
(1)高(gao)溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)顯著的(de)特(te)征是高(gao)溫(wen)(wen)穩定(ding)性(xing)(xing)(xing)(xing)(xing)(xing)(xing),雖(sui)然(ran)常(chang)(chang)溫(wen)(wen)下(xia)(xia)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)的(de)強度(du)僅是天然(ran)橡(xiang)(xiang)膠(jiao)(jiao)或(huo)某些合(he)成橡(xiang)(xiang)膠(jiao)(jiao)的(de)一(yi)半,但在200℃以上的(de)高(gao)溫(wen)(wen)環(huan)境下(xia)(xia),硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)仍能(neng)(neng)保持一(yi)定(ding)的(de)柔韌性(xing)(xing)(xing)(xing)(xing)(xing)(xing)、回彈性(xing)(xing)(xing)(xing)(xing)(xing)(xing)和(he)表面硬度(du),且力學(xue)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)無(wu)(wu)明顯變(bian)化(hua)。(2)低(di)溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)的(de)玻璃化(hua)溫(wen)(wen)度(du)一(yi)般為(wei)-70~-50℃,特(te)殊配(pei)方可達-100℃,表明其(qi)低(di)溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)優異(yi)。這對(dui)航空(kong)、宇航工(gong)業(ye)的(de)意義重(zhong)大。(3)耐(nai)候(hou)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)中Si-O-Si鍵對(dui)氧(yang)(yang)、臭氧(yang)(yang)及(ji)紫外線等(deng)十分穩定(ding),在不加任何添(tian)加劑的(de)情況(kuang)下(xia)(xia),就(jiu)具(ju)(ju)(ju)有(you)(you)(you)優良的(de)耐(nai)候(hou)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)。(4)電氣性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)具(ju)(ju)(ju)有(you)(you)(you)優異(yi)的(de)絕緣性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng),耐(nai)電暈性(xing)(xing)(xing)(xing)(xing)(xing)(xing)和(he)耐(nai)電弧性(xing)(xing)(xing)(xing)(xing)(xing)(xing)也非常(chang)(chang)好。(5)物理(li)機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)常(chang)(chang)溫(wen)(wen)下(xia)(xia)的(de)物理(li)機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)比通(tong)(tong)用橡(xiang)(xiang)膠(jiao)(jiao)差(cha),但在150℃的(de)高(gao)溫(wen)(wen)和(he)-50℃的(de)低(di)溫(wen)(wen)下(xia)(xia),其(qi)物理(li)機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)優于通(tong)(tong)用橡(xiang)(xiang)膠(jiao)(jiao)。(6)耐(nai)油(you)及(ji)化(hua)學(xue)試劑性(xing)(xing)(xing)(xing)(xing)(xing)(xing)。普通(tong)(tong)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)具(ju)(ju)(ju)有(you)(you)(you)中等(deng)的(de)耐(nai)油(you)、耐(nai)溶劑性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。(7)氣體透過性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。室溫(wen)(wen)下(xia)(xia)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)對(dui)空(kong)氣、氮、氧(yang)(yang)、二氧(yang)(yang)化(hua)碳等(deng)氣體的(de)透氣性(xing)(xing)(xing)(xing)(xing)(xing)(xing)比天然(ran)橡(xiang)(xiang)膠(jiao)(jiao)高(gao)出(chu)30-50倍。(8)生理(li)惰(duo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)。硅(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)無(wu)(wu)毒,無(wu)(wu)味,無(wu)(wu)嗅,與(yu)人體組織不粘連,具(ju)(ju)(ju)有(you)(you)(you)抗凝血(xue)作(zuo)用,對(dui)肌體組織的(de)反應性(xing)(xing)(xing)(xing)(xing)(xing)(xing)非常(chang)(chang)少。特(te)別適合(he)作(zuo)為(wei)醫用材料。
硅橡膠的用量
據中國(guo)汽(qi)(qi)(qi)車工業(ye)協(xie)會(hui)統計,2012年(nian),汽(qi)(qi)(qi)車產銷分別達到1927.18萬(wan)輛(liang)和(he)1930.64萬(wan)輛(liang),同比(bi)分別增長4.63%和(he)4.33%,汽(qi)(qi)(qi)車工業(ye)硅橡膠(jiao)的(de)用(yong)(yong)(yong)量(liang)約達2.0萬(wan)t。根據觀研天下(xia)的(de)新研究,增加(jia)(jia)有機(ji)硅材(cai)料在汽(qi)(qi)(qi)車零部(bu)(bu)件方面的(de)用(yong)(yong)(yong)量(liang),可以大幅(fu)度提高汽(qi)(qi)(qi)車的(de)安全性能,因此,汽(qi)(qi)(qi)車產量(liang)和(he)單車用(yong)(yong)(yong)量(liang)水平(ping)的(de)提高都將(jiang)推動汽(qi)(qi)(qi)車工業(ye)對硅橡膠(jiao)需求(qiu)的(de)增加(jia)(jia)。國(guo)家鼓勵自(zi)主(zhu)品(pin)牌(pai)的(de)汽(qi)(qi)(qi)車發展,關鍵汽(qi)(qi)(qi)車零部(bu)(bu)件實現自(zi)主(zhu)化,《2012年(nian)度黨(dang)政(zheng)(zheng)機(ji)關公務用(yong)(yong)(yong)車選(xuan)用(yong)(yong)(yong)車型目錄(征求(qiu)意(yi)見稿)》為(wei)(wei)(wei)自(zi)主(zhu)品(pin)牌(pai)擴大在政(zheng)(zheng)府采(cai)購(gou)(gou)的(de)市場份額(e),為(wei)(wei)(wei)改(gai)變目前國(guo)內政(zheng)(zheng)府采(cai)購(gou)(gou)以合資品(pin)牌(pai)產品(pin)為(wei)(wei)(wei)主(zhu)的(de)局面提供了保障。促(cu)進自(zi)主(zhu)品(pin)牌(pai)發展,國(guo)產汽(qi)(qi)(qi)車業(ye)的(de)繁榮將(jiang)為(wei)(wei)(wei)汽(qi)(qi)(qi)車膠(jiao)的(de)應(ying)用(yong)(yong)(yong)提供有力保障。預(yu)測未來(lai)3年(nian),我國(guo)室溫硫化硅橡膠(jiao)在汽(qi)(qi)(qi)車行業(ye)將(jiang)以年(nian)均20%增長。
此外,硅(gui)(gui)橡(xiang)(xiang)膠(jiao)是重要的(de)(de)非(fei)石油基(ji)(ji)合(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao),約占非(fei)石油基(ji)(ji)合(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao)消(xiao)費量的(de)(de)98%。但(dan)因為(wei)(wei)(wei)石油價格的(de)(de)大(da)幅(fu)上(shang)漲,同(tong)時我國(guo)(guo)在(zai)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)關鍵原料有(you)(you)機(ji)硅(gui)(gui)單(dan)體(ti)的(de)(de)生產技(ji)術方(fang)面取得突破,有(you)(you)機(ji)硅(gui)(gui)單(dan)體(ti)的(de)(de)生產技(ji)術在(zai)2005年前(qian)被(bei)幾家跨國(guo)(guo)公司壟斷,但(dan)目前(qian)我國(guo)(guo)已發展成(cheng)(cheng)為(wei)(wei)(wei)全球有(you)(you)機(ji)硅(gui)(gui)單(dan)體(ti)第1大(da)國(guo)(guo),這2個方(fang)面原因使硅(gui)(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)價格從(cong)2011年起開始低于石油基(ji)(ji)合(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao),僅約為(wei)(wei)(wei)大(da)宗石油基(ji)(ji)橡(xiang)(xiang)膠(jiao)的(de)(de)80%~90%,成(cheng)(cheng)為(wei)(wei)(wei)廉(lian)價的(de)(de)合(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao),并(bing)開始大(da)規模(mo)替代石油基(ji)(ji)合(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao)。這將極大(da)拓展有(you)(you)機(ji)硅(gui)(gui)產業的(de)(de)市場空間,同(tong)時將帶動硅(gui)(gui)油、硅(gui)(gui)烷偶聯劑(ji)和(he)硅(gui)(gui)樹脂(zhi)等其他有(you)(you)機(ji)硅(gui)(gui)產品的(de)(de)消(xiao)費。