硅橡膠是(shi)指主鏈由(you)硅(gui)和(he)氧原子(zi)交替(ti)構(gou)成,硅(gui)原子(zi)上通常(chang)連有(you)兩個有(you)機基團(tuan)的(de)(de)(de)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)。普(pu)通的(de)(de)(de)硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)主要由(you)含甲基和(he)少量(liang)乙烯基的(de)(de)(de)硅(gui)氧鏈節組成。苯基的(de)(de)(de)引入(ru)可(ke)提(ti)高硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)(de)(de)耐(nai)高、低溫(wen)性(xing)能(neng)(neng)(neng),三氟丙基及(ji)氰基的(de)(de)(de)引入(ru)則可(ke)提(ti)高硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)(de)(de)耐(nai)溫(wen)及(ji)耐(nai)油性(xing)能(neng)(neng)(neng)。硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)耐(nai)低溫(wen)性(xing)能(neng)(neng)(neng)良好,一般在(zai)-55℃下仍能(neng)(neng)(neng)工(gong)作。引入(ru)苯基后(hou),可(ke)達-73℃。硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)(de)(de)耐(nai)熱性(xing)能(neng)(neng)(neng)也很突出,在(zai)180℃下可(ke)長(chang)期(qi)工(gong)作,稍高于200℃也能(neng)(neng)(neng)承受(shou)數(shu)周(zhou)或更長(chang)時間仍有(you)彈性(xing),瞬時可(ke)耐(nai)300℃以(yi)上的(de)(de)(de)高溫(wen)。硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)(de)(de)透氣性(xing)好,氧氣透過(guo)率在(zai)合(he)(he)成聚(ju)合(he)(he)物中是(shi)較(jiao)高的(de)(de)(de)。此外(wai),硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)還具有(you)生理惰性(xing)、不會導致凝血的(de)(de)(de)突出特性(xing),因此在(zai)醫用(yong)(yong)領域應(ying)用(yong)(yong)廣泛。
主要品種
硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)分類(lei)的(de)(de)方法很多(duo),通(tong)(tong)常按(an)(an)固化前的(de)(de)形(xing)態分為(wei)(wei)固體(ti)硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)和(he)液體(ti)硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao);按(an)(an)硫化溫(wen)度分為(wei)(wei)室溫(wen)硫化硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao),高溫(wen)硫化硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao);按(an)(an)所用單體(ti)的(de)(de)不同,可(ke)分為(wei)(wei)甲(jia)基(ji)(ji)乙烯(xi)基(ji)(ji)硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao),甲(jia)基(ji)(ji)苯(ben)基(ji)(ji)乙烯(xi)基(ji)(ji)硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)、氟硅(gui)(gui)(gui),腈硅(gui)(gui)(gui)橡(xiang)膠(jiao)(jiao)等;按(an)(an)性能和(he)用途的(de)(de)不同又可(ke)分為(wei)(wei)通(tong)(tong)用型、超耐低溫(wen)型、超耐高溫(wen)型、高強力型、耐油型、醫用型等等。
發展史
硅橡(xiang)(xiang)膠早期是由美國(guo)以三氯化(hua)鐵為催化(hua)劑合成的(de)(de)(de)(de)。1945年,硅橡(xiang)(xiang)膠產(chan)(chan)品問世(shi)。1948年,采用(yong)高比表(biao)面積的(de)(de)(de)(de)氣相(xiang)法白炭黑補強(qiang)的(de)(de)(de)(de)硅橡(xiang)(xiang)膠研(yan)制成功,使(shi)硅橡(xiang)(xiang)膠的(de)(de)(de)(de)性(xing)能躍升(sheng)到(dao)實(shi)用(yong)階(jie)段(duan),奠(dian)定了現代硅橡(xiang)(xiang)膠生產(chan)(chan)技術的(de)(de)(de)(de)基(ji)礎。從(cong)二甲基(ji)二氯硅烷合成開(kai)始生產(chan)(chan)硅橡(xiang)(xiang)膠的(de)(de)(de)(de)國(guo)家有(you)美國(guo)。俄羅斯、德國(guo)、日本、韓國(guo)和(he)中國(guo)等。中國(guo)硅橡(xiang)(xiang)膠的(de)(de)(de)(de)工業化(hua)研(yan)究(jiu)始于1957年,多家研(yan)究(jiu)所和(he)企(qi)業陸續開(kai)發出各(ge)種硅橡(xiang)(xiang)膠。到(dao)2003年底,中國(guo)硅橡(xiang)(xiang)膠生產(chan)(chan)能力(li)為135千噸(dun),其中高溫膠100千噸(dun)。
高溫硫化硅橡膠
高溫硫(liu)化硅橡(xiang)(xiang)膠(jiao)(jiao)是指(zhi)聚(ju)硅氧(yang)(yang)(yang)烷(wan)變成(cheng)(cheng)彈(dan)性體的過程(cheng)是經過高溫(110-170℃)硫(liu)化成(cheng)(cheng)型的。它主要以(yi)高分子量(liang)的聚(ju)甲基(ji)乙(yi)烯基(ji)硅氧(yang)(yang)(yang)烷(wan)為生膠(jiao)(jiao),混入(ru)補(bu)強(qiang)(qiang)填料(liao)、硫(liu)化劑(ji)(ji)(ji)等,在加熱加壓下(xia)硫(liu)化成(cheng)(cheng)彈(dan)性體。硅橡(xiang)(xiang)膠(jiao)(jiao)的補(bu)強(qiang)(qiang)主要是各種類型的白炭黑(hei),可使(shi)硫(liu)化膠(jiao)(jiao)的強(qiang)(qiang)度(du)增(zeng)加數十(shi)倍(bei)。有時為了降低成(cheng)(cheng)本或改善膠(jiao)(jiao)料(liao)性能及賦予硫(liu)化膠(jiao)(jiao)各種特殊的性能,也加入(ru)相應的各種添(tian)加劑(ji)(ji)(ji)。硫(liu)化劑(ji)(ji)(ji)是各種有機(ji)過氧(yang)(yang)(yang)化物或加成(cheng)(cheng)反應催(cui)化劑(ji)(ji)(ji)。
加(jia)工成型方(fang)法如(ru)圖所(suo)示(shi)。一(yi)次硫化(hua)(hua)的目(mu)的是進(jin)行高分子鏈的交聯反(fan)應;二(er)次硫化(hua)(hua)的目(mu)的是進(jin)行補(bu)充交聯、驅除硫化(hua)(hua)劑分解產物(wu)和其他揮發性(xing)化(hua)(hua)合物(wu)以(yi)穩定硫化(hua)(hua)膠的各項性(xing)能。常用的設備有開(kai)放(fang)式煉(lian)膠機、捏(nie)合機及真空密(mi)煉(lian)機。
主要性能
(1)高溫(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)顯(xian)著的(de)(de)(de)特征是高溫(wen)(wen)(wen)穩定性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing),雖然常(chang)溫(wen)(wen)(wen)下(xia)(xia)硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)(de)(de)強度僅是天(tian)然橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)或某些(xie)合成橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)(de)(de)一(yi)半,但在(zai)200℃以上(shang)的(de)(de)(de)高溫(wen)(wen)(wen)環境下(xia)(xia),硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)仍能(neng)(neng)保持一(yi)定的(de)(de)(de)柔韌性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)、回彈性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)和表面硬度,且力學(xue)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)無(wu)明顯(xian)變化(hua)。(2)低溫(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)(de)(de)玻璃(li)化(hua)溫(wen)(wen)(wen)度一(yi)般為-70~-50℃,特殊配方可達-100℃,表明其低溫(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)優(you)異。這對航(hang)空、宇航(hang)工業(ye)的(de)(de)(de)意義重大。(3)耐(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)中(zhong)Si-O-Si鍵對氧、臭(chou)氧及(ji)紫外線等(deng)十分穩定,在(zai)不加任(ren)何(he)添加劑(ji)(ji)的(de)(de)(de)情況下(xia)(xia),就具有(you)優(you)良的(de)(de)(de)耐(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)。(4)電(dian)氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)具有(you)優(you)異的(de)(de)(de)絕緣性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng),耐(nai)(nai)電(dian)暈性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)和耐(nai)(nai)電(dian)弧性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)也非常(chang)好。(5)物理(li)機械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)常(chang)溫(wen)(wen)(wen)下(xia)(xia)的(de)(de)(de)物理(li)機械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)比(bi)通(tong)(tong)用(yong)(yong)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)差,但在(zai)150℃的(de)(de)(de)高溫(wen)(wen)(wen)和-50℃的(de)(de)(de)低溫(wen)(wen)(wen)下(xia)(xia),其物理(li)機械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)優(you)于通(tong)(tong)用(yong)(yong)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)。(6)耐(nai)(nai)油及(ji)化(hua)學(xue)試劑(ji)(ji)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)。普通(tong)(tong)硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)具有(you)中(zhong)等(deng)的(de)(de)(de)耐(nai)(nai)油、耐(nai)(nai)溶劑(ji)(ji)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。(7)氣(qi)體透(tou)過性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。室(shi)溫(wen)(wen)(wen)下(xia)(xia)硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)對空氣(qi)、氮、氧、二氧化(hua)碳等(deng)氣(qi)體的(de)(de)(de)透(tou)氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)比(bi)天(tian)然橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)高出(chu)30-50倍(bei)。(8)生理(li)惰性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)。硅橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)無(wu)毒,無(wu)味,無(wu)嗅,與(yu)人體組織不粘連,具有(you)抗凝血作用(yong)(yong),對肌(ji)體組織的(de)(de)(de)反應性(xing)(xing)(xing)(xing)(xing)(xing)(xing)(xing)非常(chang)少。特別適合作為醫用(yong)(yong)材(cai)料(liao)。
硅橡膠的用量
據中國(guo)汽(qi)車工業(ye)協會(hui)統計,2012年(nian)(nian),汽(qi)車產銷(xiao)分別達到1927.18萬(wan)輛(liang)和(he)1930.64萬(wan)輛(liang),同比分別增(zeng)長4.63%和(he)4.33%,汽(qi)車工業(ye)硅橡膠(jiao)的(de)用(yong)量約(yue)達2.0萬(wan)t。根據觀(guan)研天下的(de)新研究,增(zeng)加有(you)機硅材料在汽(qi)車零(ling)部件方面的(de)用(yong)量,可以(yi)(yi)大(da)幅度(du)提(ti)高汽(qi)車的(de)安全性(xing)能,因此,汽(qi)車產量和(he)單車用(yong)量水平(ping)的(de)提(ti)高都將推動汽(qi)車工業(ye)對硅橡膠(jiao)需求(qiu)的(de)增(zeng)加。國(guo)家(jia)鼓勵自(zi)(zi)主品(pin)牌的(de)汽(qi)車發展,關鍵汽(qi)車零(ling)部件實現(xian)自(zi)(zi)主化(hua),《2012年(nian)(nian)度(du)黨政(zheng)機關公務用(yong)車選用(yong)車型目錄(征求(qiu)意見稿)》為(wei)自(zi)(zi)主品(pin)牌擴大(da)在政(zheng)府采(cai)購的(de)市(shi)場(chang)份(fen)額,為(wei)改變目前(qian)國(guo)內政(zheng)府采(cai)購以(yi)(yi)合資品(pin)牌產品(pin)為(wei)主的(de)局面提(ti)供(gong)了保(bao)障。促進自(zi)(zi)主品(pin)牌發展,國(guo)產汽(qi)車業(ye)的(de)繁榮將為(wei)汽(qi)車膠(jiao)的(de)應用(yong)提(ti)供(gong)有(you)力保(bao)障。預測未來3年(nian)(nian),我(wo)國(guo)室溫硫化(hua)硅橡膠(jiao)在汽(qi)車行(xing)業(ye)將以(yi)(yi)年(nian)(nian)均20%增(zeng)長。
此外,硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)是重要的非石油(you)基(ji)(ji)合(he)(he)成(cheng)(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao),約占非石油(you)基(ji)(ji)合(he)(he)成(cheng)(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)消費量的98%。但因(yin)為(wei)(wei)石油(you)價格的大(da)幅(fu)上漲(zhang),同(tong)時(shi)我(wo)國(guo)在(zai)硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的關鍵原料有機硅(gui)(gui)單(dan)體(ti)(ti)的生(sheng)產(chan)技術方面取(qu)得(de)突破(po),有機硅(gui)(gui)單(dan)體(ti)(ti)的生(sheng)產(chan)技術在(zai)2005年(nian)前被幾家跨國(guo)公司壟斷,但目前我(wo)國(guo)已發展(zhan)成(cheng)(cheng)(cheng)為(wei)(wei)全球有機硅(gui)(gui)單(dan)體(ti)(ti)第(di)1大(da)國(guo),這2個(ge)方面原因(yin)使硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的價格從2011年(nian)起開始(shi)低于(yu)石油(you)基(ji)(ji)合(he)(he)成(cheng)(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao),僅約為(wei)(wei)大(da)宗石油(you)基(ji)(ji)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)的80%~90%,成(cheng)(cheng)(cheng)為(wei)(wei)廉價的合(he)(he)成(cheng)(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao),并(bing)開始(shi)大(da)規模(mo)替代石油(you)基(ji)(ji)合(he)(he)成(cheng)(cheng)(cheng)橡(xiang)(xiang)(xiang)膠(jiao)(jiao)(jiao)(jiao)。這將極(ji)大(da)拓展(zhan)有機硅(gui)(gui)產(chan)業的市(shi)場空間,同(tong)時(shi)將帶動(dong)硅(gui)(gui)油(you)、硅(gui)(gui)烷偶(ou)聯劑和硅(gui)(gui)樹脂等其(qi)他有機硅(gui)(gui)產(chan)品的消費。