硅橡膠是指主鏈由硅和氧原子交替(ti)構成,硅原子上(shang)通常連有兩個有機基(ji)團的(de)橡(xiang)膠(jiao)(jiao)(jiao)(jiao)。普通的(de)硅橡(xiang)膠(jiao)(jiao)(jiao)(jiao)主要由含甲(jia)基(ji)和少量乙烯基(ji)的(de)硅氧鏈節(jie)組成。苯基(ji)的(de)引入可提高(gao)硅橡(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)耐(nai)(nai)高(gao)、低(di)溫(wen)(wen)性(xing)(xing)(xing)能(neng),三(san)氟丙基(ji)及(ji)氰基(ji)的(de)引入則可提高(gao)硅橡(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)耐(nai)(nai)溫(wen)(wen)及(ji)耐(nai)(nai)油性(xing)(xing)(xing)能(neng)。硅橡(xiang)膠(jiao)(jiao)(jiao)(jiao)耐(nai)(nai)低(di)溫(wen)(wen)性(xing)(xing)(xing)能(neng)良好,一(yi)般在-55℃下仍(reng)能(neng)工(gong)作。引入苯基(ji)后(hou),可達-73℃。硅橡(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)耐(nai)(nai)熱性(xing)(xing)(xing)能(neng)也很突(tu)出,在180℃下可長(chang)(chang)期工(gong)作,稍高(gao)于(yu)200℃也能(neng)承受數周(zhou)或更長(chang)(chang)時間仍(reng)有彈性(xing)(xing)(xing),瞬時可耐(nai)(nai)300℃以上(shang)的(de)高(gao)溫(wen)(wen)。硅橡(xiang)膠(jiao)(jiao)(jiao)(jiao)的(de)透氣(qi)性(xing)(xing)(xing)好,氧氣(qi)透過率在合成聚合物中是較高(gao)的(de)。此(ci)外(wai),硅橡(xiang)膠(jiao)(jiao)(jiao)(jiao)還(huan)具有生理惰性(xing)(xing)(xing)、不會導致(zhi)凝血的(de)突(tu)出特性(xing)(xing)(xing),因(yin)此(ci)在醫用領(ling)域應用廣泛。
主要品種
硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)分(fen)類(lei)的方法很(hen)多,通(tong)常按固化(hua)前的形態(tai)分(fen)為(wei)固體(ti)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)和(he)液體(ti)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao);按硫化(hua)溫度分(fen)為(wei)室溫硫化(hua)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao),高溫硫化(hua)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao);按所(suo)用(yong)單體(ti)的不同(tong),可分(fen)為(wei)甲(jia)基(ji)乙(yi)烯(xi)基(ji)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao),甲(jia)基(ji)苯基(ji)乙(yi)烯(xi)基(ji)硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)、氟硅,腈硅橡(xiang)(xiang)膠(jiao)(jiao)(jiao)等(deng);按性能(neng)和(he)用(yong)途的不同(tong)又可分(fen)為(wei)通(tong)用(yong)型(xing)、超耐低溫型(xing)、超耐高溫型(xing)、高強力型(xing)、耐油型(xing)、醫用(yong)型(xing)等(deng)等(deng)。
發展史
硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)早期是由美國以(yi)三氯化(hua)鐵為催化(hua)劑合成的。1945年,硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)產品問世。1948年,采用高比(bi)表面積的氣相法白炭黑補強的硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)研制(zhi)成功,使硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)的性能躍升到(dao)實用階段(duan),奠定了(le)現(xian)代(dai)硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)生(sheng)產技術的基礎。從二甲基二氯硅(gui)烷合成開始(shi)(shi)生(sheng)產硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)的國家有(you)美國。俄羅(luo)斯(si)、德國、日本、韓國和(he)中(zhong)國等。中(zhong)國硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)的工業化(hua)研究(jiu)始(shi)(shi)于1957年,多家研究(jiu)所(suo)和(he)企業陸續(xu)開發出(chu)各種硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)。到(dao)2003年底,中(zhong)國硅(gui)橡(xiang)(xiang)(xiang)膠(jiao)生(sheng)產能力(li)為135千噸,其中(zhong)高溫(wen)膠(jiao)100千噸。
高溫硫化硅橡膠
高(gao)溫硫(liu)化(hua)(hua)(hua)(hua)硅橡膠是指(zhi)聚(ju)硅氧烷變成(cheng)彈性體的(de)(de)過程(cheng)是經過高(gao)溫(110-170℃)硫(liu)化(hua)(hua)(hua)(hua)成(cheng)型的(de)(de)。它主(zhu)要以高(gao)分(fen)子(zi)量(liang)的(de)(de)聚(ju)甲基(ji)乙烯基(ji)硅氧烷為生膠,混入(ru)補強填料、硫(liu)化(hua)(hua)(hua)(hua)劑(ji)等,在(zai)加熱加壓(ya)下硫(liu)化(hua)(hua)(hua)(hua)成(cheng)彈性體。硅橡膠的(de)(de)補強主(zhu)要是各(ge)種(zhong)類(lei)型的(de)(de)白炭黑(hei),可使硫(liu)化(hua)(hua)(hua)(hua)膠的(de)(de)強度增(zeng)加數十倍。有時為了降低成(cheng)本或改善(shan)膠料性能及賦(fu)予硫(liu)化(hua)(hua)(hua)(hua)膠各(ge)種(zhong)特(te)殊(shu)的(de)(de)性能,也加入(ru)相應的(de)(de)各(ge)種(zhong)添(tian)加劑(ji)。硫(liu)化(hua)(hua)(hua)(hua)劑(ji)是各(ge)種(zhong)有機過氧化(hua)(hua)(hua)(hua)物或加成(cheng)反(fan)應催化(hua)(hua)(hua)(hua)劑(ji)。
加工成型(xing)方法如圖所示。一(yi)次硫化(hua)的(de)目的(de)是(shi)進(jin)行高分子鏈的(de)交聯反(fan)應;二次硫化(hua)的(de)目的(de)是(shi)進(jin)行補充(chong)交聯、驅(qu)除(chu)硫化(hua)劑分解產物和其他揮發性(xing)化(hua)合(he)物以穩定硫化(hua)膠的(de)各項性(xing)能。常用的(de)設(she)備(bei)有開放式(shi)煉(lian)膠機、捏合(he)機及(ji)真空密煉(lian)機。
主要性能
(1)高(gao)(gao)(gao)(gao)溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)。硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)顯著的特征是(shi)高(gao)(gao)(gao)(gao)溫(wen)(wen)穩(wen)定(ding)性(xing)(xing)(xing)(xing)(xing)(xing)(xing),雖然(ran)(ran)常(chang)溫(wen)(wen)下硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的強度僅是(shi)天然(ran)(ran)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)或(huo)某些合成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的一半,但在(zai)(zai)200℃以上的高(gao)(gao)(gao)(gao)溫(wen)(wen)環境下,硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)仍(reng)能(neng)(neng)(neng)保持(chi)一定(ding)的柔(rou)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,且力學性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)無明(ming)顯變化(hua)。(2)低溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)的玻璃化(hua)溫(wen)(wen)度一般為-70~-50℃,特殊配(pei)方可達-100℃,表明(ming)其低溫(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)優異。這(zhe)對航(hang)空、宇航(hang)工業的意(yi)義重大。(3)耐(nai)(nai)(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)(xing)硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)中(zhong)Si-O-Si鍵對氧(yang)、臭氧(yang)及紫外線等十分(fen)穩(wen)定(ding),在(zai)(zai)不加(jia)任(ren)何添加(jia)劑的情況下,就具(ju)(ju)有(you)(you)優良(liang)的耐(nai)(nai)(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)(xing)。(4)電(dian)氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)。硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)具(ju)(ju)有(you)(you)優異的絕緣性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng),耐(nai)(nai)(nai)(nai)電(dian)暈性(xing)(xing)(xing)(xing)(xing)(xing)(xing)和(he)耐(nai)(nai)(nai)(nai)電(dian)弧(hu)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)也(ye)非(fei)(fei)常(chang)好(hao)。(5)物理(li)機械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)。硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)常(chang)溫(wen)(wen)下的物理(li)機械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)比(bi)通(tong)用橡(xiang)(xiang)膠(jiao)(jiao)(jiao)差,但在(zai)(zai)150℃的高(gao)(gao)(gao)(gao)溫(wen)(wen)和(he)-50℃的低溫(wen)(wen)下,其物理(li)機械性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)優于通(tong)用橡(xiang)(xiang)膠(jiao)(jiao)(jiao)。(6)耐(nai)(nai)(nai)(nai)油及化(hua)學試劑性(xing)(xing)(xing)(xing)(xing)(xing)(xing)。普(pu)通(tong)硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)具(ju)(ju)有(you)(you)中(zhong)等的耐(nai)(nai)(nai)(nai)油、耐(nai)(nai)(nai)(nai)溶劑性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)。(7)氣(qi)體(ti)(ti)透(tou)(tou)過性(xing)(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)(neng)。室(shi)溫(wen)(wen)下硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)對空氣(qi)、氮、氧(yang)、二氧(yang)化(hua)碳(tan)等氣(qi)體(ti)(ti)的透(tou)(tou)氣(qi)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)比(bi)天然(ran)(ran)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)高(gao)(gao)(gao)(gao)出30-50倍(bei)。(8)生理(li)惰性(xing)(xing)(xing)(xing)(xing)(xing)(xing)。硅(gui)(gui)(gui)橡(xiang)(xiang)膠(jiao)(jiao)(jiao)無毒,無味,無嗅,與(yu)人(ren)體(ti)(ti)組織(zhi)(zhi)不粘(zhan)連,具(ju)(ju)有(you)(you)抗凝血作用,對肌體(ti)(ti)組織(zhi)(zhi)的反應性(xing)(xing)(xing)(xing)(xing)(xing)(xing)非(fei)(fei)常(chang)少(shao)。特別適(shi)合作為醫用材(cai)料(liao)。
硅橡膠的用量
據中國汽(qi)(qi)(qi)(qi)車(che)(che)工(gong)業協會統(tong)計,2012年(nian),汽(qi)(qi)(qi)(qi)車(che)(che)產銷(xiao)分別達到1927.18萬(wan)(wan)輛(liang)和(he)1930.64萬(wan)(wan)輛(liang),同比分別增長4.63%和(he)4.33%,汽(qi)(qi)(qi)(qi)車(che)(che)工(gong)業硅橡膠(jiao)的(de)(de)用(yong)(yong)(yong)量約達2.0萬(wan)(wan)t。根據觀研天下(xia)的(de)(de)新(xin)研究(jiu),增加(jia)有機硅材料在(zai)汽(qi)(qi)(qi)(qi)車(che)(che)零部(bu)件(jian)方面的(de)(de)用(yong)(yong)(yong)量,可(ke)以(yi)大(da)幅度(du)提高汽(qi)(qi)(qi)(qi)車(che)(che)的(de)(de)安全(quan)性能,因此,汽(qi)(qi)(qi)(qi)車(che)(che)產量和(he)單車(che)(che)用(yong)(yong)(yong)量水平(ping)的(de)(de)提高都將推動汽(qi)(qi)(qi)(qi)車(che)(che)工(gong)業對硅橡膠(jiao)需求的(de)(de)增加(jia)。國家(jia)鼓(gu)勵自主品(pin)牌(pai)(pai)的(de)(de)汽(qi)(qi)(qi)(qi)車(che)(che)發展,關鍵汽(qi)(qi)(qi)(qi)車(che)(che)零部(bu)件(jian)實(shi)現自主化,《2012年(nian)度(du)黨政機關公務(wu)用(yong)(yong)(yong)車(che)(che)選用(yong)(yong)(yong)車(che)(che)型目錄(征求意見稿)》為自主品(pin)牌(pai)(pai)擴大(da)在(zai)政府(fu)采(cai)購的(de)(de)市場份額,為改變目前國內政府(fu)采(cai)購以(yi)合(he)資品(pin)牌(pai)(pai)產品(pin)為主的(de)(de)局面提供了保障。促進自主品(pin)牌(pai)(pai)發展,國產汽(qi)(qi)(qi)(qi)車(che)(che)業的(de)(de)繁榮(rong)將為汽(qi)(qi)(qi)(qi)車(che)(che)膠(jiao)的(de)(de)應用(yong)(yong)(yong)提供有力保障。預測(ce)未來3年(nian),我(wo)國室溫硫化硅橡膠(jiao)在(zai)汽(qi)(qi)(qi)(qi)車(che)(che)行業將以(yi)年(nian)均20%增長。
此外,硅(gui)(gui)橡(xiang)(xiang)膠(jiao)是重要的(de)(de)非石(shi)(shi)油(you)(you)(you)基合(he)(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao),約(yue)占非石(shi)(shi)油(you)(you)(you)基合(he)(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao)消(xiao)費量(liang)的(de)(de)98%。但因(yin)為(wei)(wei)石(shi)(shi)油(you)(you)(you)價格的(de)(de)大幅上(shang)漲,同時我國在(zai)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)關鍵原料(liao)有(you)機硅(gui)(gui)單體(ti)的(de)(de)生產(chan)技(ji)術方(fang)面(mian)取得突破,有(you)機硅(gui)(gui)單體(ti)的(de)(de)生產(chan)技(ji)術在(zai)2005年前(qian)被幾(ji)家跨國公司壟斷,但目(mu)前(qian)我國已(yi)發展(zhan)(zhan)成(cheng)(cheng)為(wei)(wei)全球有(you)機硅(gui)(gui)單體(ti)第1大國,這2個方(fang)面(mian)原因(yin)使(shi)硅(gui)(gui)橡(xiang)(xiang)膠(jiao)的(de)(de)價格從2011年起開始(shi)低于(yu)石(shi)(shi)油(you)(you)(you)基合(he)(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao),僅約(yue)為(wei)(wei)大宗石(shi)(shi)油(you)(you)(you)基橡(xiang)(xiang)膠(jiao)的(de)(de)80%~90%,成(cheng)(cheng)為(wei)(wei)廉價的(de)(de)合(he)(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao),并開始(shi)大規模替代(dai)石(shi)(shi)油(you)(you)(you)基合(he)(he)(he)成(cheng)(cheng)橡(xiang)(xiang)膠(jiao)。這將(jiang)極大拓展(zhan)(zhan)有(you)機硅(gui)(gui)產(chan)業的(de)(de)市(shi)場空間,同時將(jiang)帶(dai)動硅(gui)(gui)油(you)(you)(you)、硅(gui)(gui)烷偶聯劑和硅(gui)(gui)樹脂(zhi)等其(qi)他有(you)機硅(gui)(gui)產(chan)品的(de)(de)消(xiao)費。