| 塑料中常用的添加剂之紫外线吸收剂 |
| 添加时间：2018/1/16 14:44:39 浏览次数： |
| 紫外线吸收剂是塑料制品中非常重要的添加剂，是一种起光稳定作用的稳定剂，其主要是借吸收和转化太阳光中具有破坏性的紫外光部分而产生稳定效果。紫外线吸收剂主要应用于塑料制品中，如板材、线缆、管材等厚制品，在很多情况下，塑料薄膜中也会加入紫外线吸收剂，以抑制或延缓紫外光对被防护物品或物质的负面作用。 Ultraviolet absorber is a very important additive in plastic products. It is a stabilizer that plays the role of light stability. It mainly produces stable effect by absorbing and converting destructive ultraviolet parts in sunlight. UV absorbers are mainly used in plastic products, such as plates, cables, pipes and other thick products. In many cases, ultraviolet absorbers are added to plastic films to inhibit or postpone the negative effects of ultraviolet light on the protected articles or substances. 紫外线及其对塑料等聚合物的破坏作用 UV and its damage to polymers such as plastics 我们都知道，从太阳发射出来的辐射线，其电磁波是非常宽的，能够到达地面的主要包括紫外线、可见光和红外线等。辐射线的能量与波长成反比，波长越短，能量越大。其中290nm-400nm波长范围内的紫外线，波长最短，能量也最高，其对塑料等聚合物的破坏性也最大，有机聚合物的键能通常在290~400kJ/mol范围内，故很容易为紫外线所破坏。因此，紫外线是影响塑料光老化的主要因素。但要注意的是不同结构的高分子化合物对紫外线各种不同长短波段的敏感程度是不一样的。 We all know that the electromagnetic radiation emitted from the sun is very wide, and it can reach the ground mainly including ultraviolet, visible and infrared. The energy of the radiant line is inversely proportional to the wavelength. The shorter the wavelength, the greater the energy. Ultraviolet radiation in the 290nm-400nm wavelength range is the shortest and the energy is the highest. It has the most destructive effect on polymers such as plastics. The bond energy of organic polymers is usually within 290~400kJ/mol range, so it is easy to destroy by ultraviolet radiation. Therefore, UV is the main factor affecting the optical aging of plastics. However, it is important to note that different structures of polymer compounds have different sensitivity to various wavelengths of ultraviolet light. 塑料等高分子材料之所以具有许多优良性能，归结于其具有足够长的大分子链，但由于紫外线波长短、能量高，在紫外线作用（大多数还有氧的参与）下，高分子材料吸收紫外线后，容易形成电子激发态，这种激发态的分子可以引起一系列的光化学反应，即自由基链式反应，并同时与氧化相伴发生“光氧老化”或“光氧化反应”。高分子大分子链被切断或产生一定的交联，直接影响到了高分子材料的性能，于是就出现了一系列老化现象。如颜色变深、发脆、变硬、表面龟裂以及机械性能与电性能下降等，以致最后丧失其使用价值。 Plastic and other polymer materials have many excellent properties due to its large molecular chain is long enough, but due to UV wave length, high energy, in the ultraviolet (and most oxygen involved), polymer materials absorb ultraviolet light, easy to form electronic excited states, the excited molecules can cause photochemical reaction a series of free radical chain reaction, and at the same time and oxidation associated "aging" or "photooxygenation". The macromolecule chain of macromolecule is cut off or produced a certain cross-linking, which directly affects the properties of polymer materials, so a series of aging phenomena appear. For example, the color becomes deep, brittle, hardened, surface cracked, and the mechanical and electrical properties decrease, and the use value is lost at last. 紫外线吸收剂的概念及其作用 The concept and function of ultraviolet absorbents 高分子材料具有不同的分子结构，对紫外光的抵抗能力也自然不同,也就是说不同高分子材料的“光稳定性”不同。对于ABS、SBS等含有双键等不饱和键的高分子材料，其及容易吸收紫外光而发生光氧化反应，因此它们的光稳定性不好。但对于仅含饱和化学键的纯聚合物来说，则不吸收或几乎不吸收紫外线，因此对紫外光是稳定的。 Polymer materials have different molecular structures and different resistance to ultraviolet light, that is to say, different polymers have different optical stability. For ABS, SBS and other polymer materials containing double bonds and other unsaturated bonds, they are easy to absorb ultraviolet light and photooxidation reaction, so their optical stability is not good. But for pure polymers containing only saturated chemical bonds, they do not absorb or almost do not absorb ultraviolet light, so it is stable for ultraviolet light. ABS紫外老化前后对比图 Contrast diagram of ABS before and after ultraviolet aging 但实际情况是，这种具有饱和键的纯聚合物是不存在的，因为在聚合物的工业化生产过程中，如聚合、挤出造粒、注塑、储存等过程中不可避免的引入催化剂残留、微量氢过氧化物等一些杂质，这些杂质对光敏感，在吸收紫外线后，进而会引发材料的光老化反应。 But the reality is that this is pure polymer saturated bond does not exist, because in the process of industrial production of polymer, unavoidable processes such as polymerization, extruding and injection and storage in residual catalyst, hydrogen peroxide and some trace impurities, these impurities are sensitive to light, in the absorption of ultraviolet light, and the materials bring light aging reaction. 紫外线吸收剂是目前应用最广的一类光稳定剂。它能强烈地、选择性地吸收高能量的紫外光，并以能量转换形式，将吸收的能量以热能或无害的低能辐射释放出来或耗掉，从而防止塑料中的发色团吸收紫外线能量随之发生激发。 Ultraviolet absorbent is one of the most widely used light stabilizers. It can strongly and selectively absorb ultraviolet light with high energy, and the energy conversion form, absorption of energy to heat or harmless low-energy radiation released or consumed, thereby preventing plastic chromophores absorb ultraviolet energy with excitation. 紫外线吸收剂的分类 Classification of ultraviolet absorbents 紫外线吸收剂所包括的化合物类型比较广泛。按结构来划分，主要包括二苯甲酮类、水杨酸酯类、苯并三唑类、取代丙烯腈类、三嗪类等。塑料工业中应用最多的当属二苯甲酮类和苯并三唑类等。 The types of compounds included in ultraviolet absorbents are widely used. According to the structure, it mainly includes two benzophenones, salicylic acid esters, benzo and three azole, substituted acrylonitrile and three azine. The most widely used plastics industry is the two benzophenone class and the benzo - three azolol. 二苯甲酮类紫外线吸收剂是目前应用最广的一类紫外线吸收剂，它对整个紫外光区域几乎都有吸收作用，光稳定机理是其分子中苯环上的羟基氢和相邻的羰基氧之间形成了分子内氢键，构成了一个鳌合环，而当吸收紫外光能量后，分子发生热振动，氢键破坏，鳌合环打开，这样就能把有害的紫外光变成无害的热能而释出来。二笨甲酮类紫外线吸收剂中，必须要有一邻位的羟基，否则不能作为聚合物的光稳定剂。这一类紫外线吸收剂的典型代表品种有UV-531、UV-9等等。 Two benzophenone UV absorber is a kind of ultraviolet absorbent is currently the most widely used, it in the ultraviolet region almost all absorption, light stabilizing mechanism is intramolecular hydrogen bonds were formed between the carbonyl oxygen and hydroxyl hydrogen adjacent on the benzene ring in the molecule, forming a chelate ring, and when the absorption of UV molecular energy, thermal vibration, destruction of hydrogen bonds, chelate ring open, so that the harmful ultraviolet light into harmless heat and release out. Two of the UV Absorbents of ketones must have a neighborhood of the hydroxyl group, otherwise it can not be used as a light stabilizer for the polymer. The typical varieties of this type of ultraviolet absorbents are UV-531, UV-9 and so on. UV-531分子结构式及物状 UV-531 molecular structural transitivity 水杨酸酯类紫外线吸收剂为应用最早的一类紫外线吸收剂。它可在分子内形成氢键，其本身对紫外线吸收能力很低，而且吸收的波长范围极窄(小于340nm )。但在吸收一定能量后，由于发生分子重排。形成了吸收紫外线能力强的二苯甲酮结构，从而产生强的光稳定作用。 The UV Absorbents of salicylic acid esters are the earliest type of ultraviolet absorbent. It can form a hydrogen bond within the molecule, which itself has a very low absorption capacity for ultraviolet light, and the wavelength range of absorption is very narrow (less than 340nm). But after a certain amount of energy is absorbed, the rearrangement of molecules occurs. The structure of two benzophenone with strong ultraviolet absorptive capacity is formed, thus producing strong light stabilization. 邻羟基苯甲酸苯酯分子结构式 Molecular structural formula of phthalate benzoate 苯并三唑类紫外线吸收剂，其光稳定机理与二苯甲酮类相似，其分子中也存在氢键鳌合环，由羟基氧与三唑基上的氮所形成。当吸收紫外光后，氢键破坏或变为光互变异构体，把有害的紫外光能变成无害的热能。这一类紫外线吸收剂的典型代表品种有UV-P、UV-326、UV-327、UV-329等等。 Benzo three azole ultraviolet absorbers are similar to two benzophenones in light stabilization mechanism. There are also hydrogen bonding rings in their molecules, formed by hydroxyl oxygen and nitrogen on three azolyl groups. When ultraviolet light is absorbed, the hydrogen bond destroys or turns into a light cross - variant structure, turning harmful ultraviolet light into harmless heat. The typical varieties of this type of UV Absorbents are UV-P, UV-326, UV-327, UV-329 and so on. UV-327分子结构式 UV-327 molecular structure UV-326分子结构式 UV-326 molecular structure 紫外线吸收剂使用建议 Recommendations for the use of ultraviolet absorbents 在实际应用中，为了改善和提高塑料及其制品的光稳定性，单单添加紫外线吸收剂是达不到预期效果的。因为塑料等高分子材料的光老化 In practical applications, in order to improve and improve the optical stability of plastic and its products, a single addition of UV absorbers can not reach the desired effect. Photoaging of polymer materials such as plastics |
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