影响胶粘剂粘接强度的化学因素

发布时间:2019/04/22    发布人:

全自动封胶机厂家提示大家░,影响胶粘剂粘接强度的化学要素主要指分子的极性•●、分子量•●、分子外形(侧基几及大小)•●、分子量散布•●、分子的结晶性•●、分子对环境的稳定性(转变温度和降解)以及胶粘剂和被粘体中其它组份性质PH值等。
The manufacturer of automatic sealing machine reminds us that the chemical factors affecting the bonding strength of adhesives mainly refer to the polarity, molecular weight, molecular shape (side group number and size), molecular weight dispersion, molecular crystallinity, molecular stability to the environment (transition temperature and degradation), and the properties of adhesives and other components in the adhesives, such as PH value.
1•●、极性。胶粘剂和被粘体分子的极性影响着粘接强度░,但并不意味着这些分子极性的增加就一定会进步粘接强度。从极性的角度动身为了进步粘接强度░,与其改动胶粘剂和被粘体全局部子的极性░,还不如改动界面区外表的极性。例如聚乙烯•●、聚丙烯•●、聚四氟乙烯经等离子外表处置后░,外表上产生了许多极性基团░,如羟基•●、羰基或羧基等░,从而显着地进步了可粘接性。
1. Polarity. The polarity of adhesives and adhesives affects the bonding strength, but it does not mean that the increase of the polarity of these molecules will certainly improve the bonding strength. In order to improve the bonding strength, it is better to change the exterior polarity of the interface area than to change the polarity of the adhesive and the global part of the adhesives. For example, polyethylene, polypropylene and polytetrafluoroethylene (PTFE) have been treated by plasma. Many polar groups, such as hydroxyl, carbonyl or carboxyl groups, have been produced on the surface, which greatly improves the bondability.
2•●、分子量。聚合物的分子量(或聚合度)直接影响聚合物分子间的作用力░,而分子间作用力的大小决议物质的熔点和沸点的上下░,决议聚合物的玻璃化转变温度Tg和熔点Tm。聚合物无论是作为胶粘剂还是作为被粘体░,其分子量都影响着粘接强度。
2. Molecular weight. Molecular weight (or degree of polymerization) of polymers directly affects the intermolecular forces of polymers, and the magnitude of intermolecular forces determines the melting point and boiling point of materials, and the glass transition temperature (Tg) and melting point (Tm) of polymers. Whether polymer is used as adhesives or as adhesives, its molecular weight affects the bonding strength.
3•●、侧链。长链分子上的侧基是决议聚合物性质的重要要素。从分子间作用力思索░,聚合物支链的影响是░,当支链小时░,增加支链长度░,降低分子间作用力。当支链到达一定长度后░,开端结晶░,增加支链长度░,进步分子间作用力。这应当是降低或进步粘接强度的缘由。
3. Side chain. The side groups on long chain molecules are important factors to determine the properties of polymers. Considering the intermolecular forces, the effect of polymer branched chains is to increase the length of branched chains and reduce the intermolecular forces when the branched chains are small. When the branched chain reaches a certain length, it begins to crystallize, increases the length of the branched chain, and improves the intermolecular force. This should be the reason for reducing or improving the bonding strength.
4•●、PH值。关于某些胶粘剂░,其PH值与胶粘剂的适用期有较为亲密的关系░,影响到粘接强度和粘接寿命。普通强酸•●、强碱░,特别是当酸碱对粘接资料有很大影响时░,对粘接常是有害的░,特别是多孔的木材•●、纸张等纤维类材更容易受影响。

全自动封胶机
4, pH value. As for some adhesives, their PH value has a close relationship with the application life of the adhesives, which affects the bonding strength and bonding life. Ordinary strong acid and alkali, especially when acid and alkali have a great impact on bonding data, are often harmful to bonding, especially porous wood, paper and other fibers are more vulnerable.
由于像热固性的酚醛树脂和脲醛树脂的固化过程受PH值的影响很大░,常常请求酸度较大。例如░,固化时在酚醛树脂中参加对甲苯磺酸或磷酸░,在脲醛树脂中参加氯化铵或盐酸。因而░,在不希望酸度大又要粘接的场所░,选用中性的间苯酚甲醛树脂是适合的。
Because the curing process of phenolic and urea-formaldehyde resins, such as thermosetting resins, is greatly affected by the PH value, the acidity is often requested. For example, p-toluene sulfonic acid or phosphoric acid is added to phenolic resin during curing, and ammonium chloride or hydrochloric acid is added to urea-formaldehyde resin. Therefore, it is suitable to use neutral m-phenol formaldehyde resin in places where acidity is not expected to be high and adhesion is required.
将木材外表预先用碱处置░,普通可得到结实的接头。但还必需留意胶层的PH值░,它对胶层比对被胶接外表更有影响。
The wood appearance can be pre-treated with alkali, and generally a strong joint can be obtained. However, it is necessary to pay attention to the PH value of the adhesive layer, which has more influence on the surface of the adhesive layer than on the bonded surface.
5•●、填料。在胶粘剂中配合填料有如下作用:(1)增加胶粘剂的内聚强度;(2)调理黏度或工艺性(例如触变性);(3)进步耐热性;(4)调整热收缩系数或收缩性;(5)增大间隙的可填充性;(6)给予导电性;(7)降低价钱;(8)改善其他性质。
5. Filling. The fillers in the adhesives have the following functions: (1) increasing the cohesive strength of the adhesives; (2) adjusting the viscosity or technological properties (such as thixotropy); (3) improving the heat resistance; (4) adjusting the thermal shrinkage coefficient or shrinkage; (5) increasing the fillability of the gap; (6) giving conductivity; (7) reducing the price; (8) improving other properties.
本文精彩内容由全自动封胶机整理提供!希望通过小编的介绍对大家有所帮助░,我们的官网是:多谢大家的阅读观看!
The wonderful content of this article is provided by automatic sealing machine. Hope to help you through the introduction of the edition, our official website is: Thank you for reading and watching!

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