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目前為止，光引發(fā)自由基聚合體系應(yīng)用最為普遍，但是它也有自己不可克服的弊端限制了其應(yīng)用。自由基聚合在反應(yīng)過程中會有氧阻聚，反應(yīng)體系粘結(jié)性不好，體積收縮率高，導(dǎo)致產(chǎn)品尺寸精度降低，因應(yīng)力的產(chǎn)生使材料發(fā)生變形，易破裂，在基材上有比較差的附著力。

So far the photo-initiated free radical polymerization system is the most widely used, but it also has its own insurmountable drawbacks that limit its application. In the process of free radical polymerization, there will be oxygen inhibition. Besides, the reaction system has poor adhesion and high volume shrinkage, which may result in the reduction of dimensional accuracy of the product. The impact of stress may lead to material deformation, easy to break and poor adhesion on substrate.

對陽離子光固化體系的研究可以追溯到上個世紀(jì)，陽離子光固化有一系列自身獨(dú)特的優(yōu)點(diǎn)。首先，陽離子光聚合體系最大的優(yōu)點(diǎn)是沒有氧阻聚，不需要在一個惰性氣體氛圍中進(jìn)行反應(yīng)，既可以節(jié)省反應(yīng)成本，又可以簡化反應(yīng)條件，克服了一直限制自由基光聚合反應(yīng)的難題。陽離子光聚合是一個活性聚合反應(yīng)，一旦引發(fā)聚合即使撤離光源也不會中止反應(yīng)，有明顯的后固化反應(yīng)，使反應(yīng)進(jìn)行的更徹底，稱之為“不死聚合”，適合厚度較厚的涂層固化，而自由基聚合則十分依賴光源，一旦離開光源反應(yīng)立馬停止；陽離子光固化體系中反應(yīng)的單體或者聚合物一般不單能夠發(fā)生雙鍵聚合還能夠發(fā)生開環(huán)反應(yīng)，如環(huán)醚、乙縮醛、乙烯基醚類等等，反應(yīng)物種類增加，且毒性比丙烯酸酯類單體或聚合物要低；陽離子光固化體系發(fā)生聚合開環(huán)反應(yīng)體積會有一定膨脹，會補(bǔ)償減小聚合過程中產(chǎn)生的體積收縮，對基材的附著力大大提高，改善光固化涂層的機(jī)械性能和熱穩(wěn)定性。陽離子光固化體系中常用的單體或者低聚物為乙烯基醚類，氧雜環(huán)丁烷類和環(huán)氧類。

Research on cationic UV curing systems can be traced back to the last century, and cationic UV curing has a series of unique advantages. First of all, the biggest advantage of the cationic photopolymerization system is no oxygen inhibition. There is no need to carry out a reaction in an inert gas atmosphere, which not only saves the reaction cost, but also simplifies the reaction conditions. It also overcomes the problem that has always limited the free radical photopolymerization reaction. Cationic photopolymerization is a living polymerization reaction. Once the polymerization is initiated, the reaction will not stop even if the light source is removed. There is an obvious post-curing reaction, which makes the reaction more thorough. It is called "immortal polymerization" and suitable for thicker coatings. However, free radical polymerization is very dependent on the light source, because the reaction will stop immediately once it leaves the light source. The monomers or polymers reacted in the cationic UV curing system generally can not only undergo double-bond polymerization but also undergo ring-opening reaction, such as cyclic ethers, acetals, vinyl ethers, etc.. Reactant types are increased and the toxicity is lower than that of acrylate monomers or polymers. After polymerization and ring-opening reaction, the volume of the cationic UV curing system will expand to a certain extent, which will compensate for the reduction of the volume in the polymerization process. It also helps greatly increase the adhesion to substrate and improve the mechanical properties and thermal stability of the UV-cured coating. Commonly used monomers or oligomers in cationic UV curable systems are vinyl ethers, oxetanes and epoxies.

活性單體/Reactive monomers

在光固化體系中，活性單體雖然在反應(yīng)體系中占有比例不是最大的，但是它也是重要組成部分。一般活性單體的粘度比較低，它具有溶解光固化低聚物的作用，可以通過調(diào)節(jié)加入活性單體的量調(diào)整配方體系的粘度使其達(dá)到合適的狀態(tài)；而且活性單體擁有光固化活性基團(tuán)，可以作為反應(yīng)物參與到聚合反應(yīng)中，不會像溶劑一樣殘留在固化體系中，而且對光聚合反應(yīng)速率，固化成膜的性質(zhì)有很大的貢獻(xiàn)，減少了有機(jī)溶劑揮發(fā)對環(huán)境的污染。因?yàn)樽杂苫酆喜豢煽朔难踝杈蹎栴}，我們將重點(diǎn)介紹可進(jìn)行陽離子光固化的活性單體。

Although the active monomer does not occupy the largest proportion in the UV curing reaction system, it is still considered as an important part. Due to its relatively low viscosity, the active monomer has the function of dissolving the UV curable oligomer. The viscosity of the formulation system can be adjusted to a suitable state by adjusting the amount of the active monomer added. Moreover, the active monomer has UV curing active group, which can participate in the polymerization reaction as a reactant and it will not remain in the curing system like a solvent. Furthermore, it has a great contribution to the photopolymerization reaction rate and the properties of cured films. It also helps reduce the pollution of organic solvent on the environment. Because of the insurmountable oxygen inhibition problem of free radical polymerization, we will focus on reactive monomers that can undergo cationic UV curing.

活性單體的種類十分豐富，按照官能團(tuán)數(shù)量可以分為單、雙和多官能度三類。活性單體的反應(yīng)活性不但和官能度數(shù)相關(guān)而且與官能團(tuán)的種類也是相關(guān)，且都是正相關(guān)，光固化速率會隨之增大，轉(zhuǎn)化率增高，表面膜的交聯(lián)密度也會增大。

There are many kinds of reactive monomers. According to the number of functional groups, they can be divided into three types: mono-, bi- and multi-functional. The reactivity of reactive monomers is not only related to the number of functionalities, but also to the types of functional groups, and they are all positively related. The more functional groups they have, the higher the UV curing rate, conversion rate and cross-linking density of the surface film will be.

環(huán)氧類活性單體是現(xiàn)在應(yīng)用比較多的一類單體，環(huán)氧類單體在光固化反應(yīng)中, 發(fā)生開環(huán)反應(yīng)，且固化后固化膜體積收縮小。體積收縮會導(dǎo)致產(chǎn)品尺寸精度的下降，而且因收縮產(chǎn)生的應(yīng)力會引起材料的變形，破裂及在基材上較差的附著力，而環(huán)氧類活性光固化開環(huán)引起的體積膨脹剛好彌補(bǔ)了聚合產(chǎn)生的體積收縮，故其體積收縮小，具有優(yōu)異熱穩(wěn)定性和機(jī)械性能。但是，環(huán)氧類的活性單體因?yàn)榉磻?yīng)速率常數(shù)比較低，所以其反應(yīng)速率比同官能團(tuán)的丙烯酸酯類單體要低。但脂環(huán)族環(huán)氧反應(yīng)速率比較快，且聚合產(chǎn)物具有較好的耐候性和電絕緣性，在陽離子光固化體系中應(yīng)用十分廣泛。

Epoxy-based reactive monomers are a type of monomers which have been widely used now. These monomers will undergo a ring-opening reaction in the UV curing process and the volume shrinkage of the cured film is small. Volume shrinkage may lead to a decrease in dimensional accuracy of the product. The stress generated by shrinkage may cause material deformation, cracking and poor adhesion on substrate. However, the volume expansion caused by UV curing and ring opening of epoxy-based reactive monomers just makes up for the volume shrinkage produced by polymerization, so it has excellent thermal stability and mechanical properties in addition to small volume shrinkage. The reaction rate of epoxy-based reactive monomers is lower than that of acrylate-based monomers with the same functional group. However, the reaction rate of cycloaliphatic epoxies is relatively fast and the polymer product has good weather resistance and electrical insulation, so it is widely used in cationic UV curing system.

氧雜環(huán)丁烷類活性單體的環(huán)張力（107KJ/mol）類似于脂肪族環(huán)氧，只比脂環(huán)族環(huán)氧的環(huán)氧基的環(huán)張力略低一點(diǎn)，但氧雜環(huán)丁烷相比脂環(huán)族環(huán)氧的堿性強(qiáng)，因而氧雜環(huán)丁烷更容易發(fā)生陽離子開環(huán)聚合，其反應(yīng)速率更快。單官能度氧雜環(huán)丁烷反應(yīng)活性不低于雙官能度的環(huán)氧甚至比其更高，而且氧雜環(huán)丁烷的粘度、毒性、揮發(fā)性和體積收縮都比較低，機(jī)械性能和熱穩(wěn)定性都性能良好，應(yīng)用于UV涂料、油墨、電子封裝、牙科樹脂、3D打印等領(lǐng)域。

The ring tension (107KJ/mol) of oxetane-based reactive monomers is similar to that of cycloaliphatic epoxies. It is only slightly lower than the ring tension of the epoxy group of cycloaliphatic epoxies. However, the basicity of cycloaliphatic epoxies is stronger than that of the oxetane, so oxetane is more prone to cationic ring-opening polymerization and its reaction rate is higher. The reactivity of mono-functional oxetane is not lower than or even higher than that of bi-functional epoxy. Furthermore, the viscosity, toxicity, volatility and volume shrinkage of oxetane are relatively low, which attributes to excellent mechanical properties and thermal stability. Applications include UV coatings, inks, electrical encapsulation, dental resins, 3D printing and so on. 

S-101

CAS-3047-32-3

Syna-Epoxy 101是一種陽離子型、紫外線固化、活性、水溶性環(huán)氧稀釋劑。

Syna-Epoxy 101 is a cationic, UV-curable, reactive and water-soluble epoxy diluent.

規(guī)格參數(shù)

Specifications

產(chǎn)品應(yīng)用

用于粘膠樹脂和涂料，適用于電子和建筑材料的粘合劑，汽車涂料和其他絕緣材料。

Product application

For adhesive resins and coatings, adhesives for electronics and building materials, automotive coatings and other insulation materials.

南通新納希新材料有限公司可提供多款氧雜環(huán)丁烷類活性單體，如S-101、S-221等牌號已廣泛應(yīng)用于各行各業(yè)中，歡迎廣大客戶來電垂詢！

Nantong Synasia New Material Co., Ltd. can provide a variety of oxetane-based reactive monomers such as S-101, S-221 and other grades. These products have been widely used in many industries. Welcome all customers to inquire!