硅烷改性聚氨酯密封膠聚體的合成

發(fā)布時(shí)間 : 2022-10-31 10:48:41
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(Summary description)Customized SILICONE STRUCTURAL SEALANT from China manufacturer refers to the adhesive with high strength, can bear large load, aging resistance, fatigue resistance and corrosion resistance, and has stable performance within the expected life. It is suitable for bearing the bonding of strong structural parts. Non structural adhesive has low strength and poor durability. It can only be used for bonding, sealing and fixing of ordinary and temporary properties, and cannot be used for structural adhesive bonding. NEUTRAL SILICONE WETHERPROOF SEALANT from China manufacturer is a structural adhesive with waterproof function. Silicone glue refers to the adhesive based on silicone rubber. According to different functions, it can be divided into structural adhesive, potting adhesive, sealant, thermal conductive adhesive, flame retardant adhesive and so on.

硅烷改性聚氨酯密封膠聚體的合成

發(fā)布時(shí)間 : 2022-10-31 10:48:41
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硅烷改性聚氨酯密封膠預(yù)聚體合成一般分兩步:首先合成硅烷改性聚氨酯密封膠預(yù)聚體，即通過調(diào)節(jié)異氛酸醋基(一NCO)與輕基(一OH)的比例(摩爾比大于或小于l)合成一NCO或一OH封端的硅烷改性聚氨酯密封膠預(yù)聚體。然后合成硅烷改性PTJ預(yù)聚體，即將第一步合成的硅烷改性聚氨酯密封膠預(yù)聚體與化學(xué)計(jì)量的硅烷反應(yīng)(硅烷過量)，生成硅烷封端的硅烷改性聚氨酯密封膠預(yù)聚體。若是一N封端的硅烷改性聚氨酯密封膠預(yù)聚體，選用含活性氫的有機(jī)官能團(tuán)(羚基或氨基)的硅烷;若是一OH封端，則選用帶一NCO官能團(tuán)的硅烷。硅烷改性聚氮酸密封膠的合成硅烷改性聚氨酯密封膠預(yù)聚體為液態(tài)流體，濕氣可固化為柔軟橡膠狀材料，延伸率相對(duì)較低，剪切和拉伸強(qiáng)度也不高，在硅烷改性PI3預(yù)聚體中加人補(bǔ)強(qiáng)劑、填料、增塑劑、顏料、固化催化劑和其他助劑后得到性能優(yōu)良的密封膠。影響硅烷改性聚氨酯密封膠性能的因素很多，存在于每個(gè)合成階段，但對(duì)其性能影響較大的是原材料的選擇和工藝配方。

用來制備PIJ預(yù)聚體的異佩酸醋大多為甲苯二異氛酸a(TDI)、二苯基甲烷二異氛酸醋(MDI)和異佛爾酮二異氛酸醋(IPDI)，其中又以TDI和MICI居多。相對(duì)來講，以3I為原料合成的PST密封膠比以MDI為原料合成的PIE密封膠成本低，戮度低且容易控制，綜合性能較優(yōu)。以前C硅烷改性聚氨酯密封膠的制備多以iDI為原料，但因以II合成P密封膠過程中存在TICI的安全操作和揮發(fā)問題(3I毒性較大)，TDI的使用量受到限制川。近年來國外很多公司采用IVII或IPII為原料，通過對(duì)它們進(jìn)行特殊改性，制得性能同樣優(yōu)良的硅烷改性聚氨酯密封膠。www.caffertyclinic.com

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上一篇: 硅烷改性聚氨酯密封膠的合成原理

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