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聚氨酯密封胶增塑剂对固化性能的影响

  • 发布时间 : 2023-2-2 11:04:35
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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.

聚氨酯密封胶增塑剂对固化性能的影响

(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.

  • 发布时间 : 2023-2-2 11:04:35
  • Views:
Information

       由图2可以看出,聚氨酯密封胶二醋酸二丁基锡的活性高于新型有机锡,加入相同份数催化剂表干时间较短,但固化速度较小。其原因是催化剂中锡含量较高。但采用二醋酸二丁基锡与新型2价有机锡催化剂以质量比1:1配合使用时表干时间适中,固化速度要明显优于2者单独使用。原因可能是由于氧原子具有较强的吸电子能力,在2价有机锡的锡原子周围形成了氧原子的环绕结构(如图3所示),从而提高了有机锡的活性。过多会导致聚氨酯密封胶体系不稳定,在老化试验后有豁度增大增稠、其至固化的现象,见表10二醋酸二丁基锡与新型2价有机锡质量比分别为2:1, 1:2进行试验,结果如表2所示。

       本体系中选用配比2做为催化剂,添加量为z份,表干时间适中,固化速度为4.01 mmJ24 h,且聚氨酯密封胶贮存稳定性好。

       在聚氨酯密封胶固化过程中,水分的扩散速度对聚氨酯密封胶的固化速度有直接影响。水分的扩散速度受高分子结构的影响。在配方设计时会添加一定量的聚氨酯密封胶增塑剂以达到降低聚氨酯密封胶赫度、提高固化物的柔顺性、降低硬度、改善拉伸性能等目的。采用与预聚物结构相似的聚氨酯密封胶增塑剂,可使水分扩散速度加快。分别加入邻苯二甲酸二癸醋(P)、三乙二醇二异辛酸醋(3G0)及聚丙二醇3000 (PPG3000)试验对比其对固化性能的影响,结果见图4。硅烷改性聚醚的主链结构为聚环氧丙烯。

       3种聚氨酯密封胶增塑剂的结构式如图5所示,PPG3000与硅烷改性聚醚的主链结构一致,结构相似的聚氨酯密封胶增塑剂与硅烷改性聚醚相容性更好,水分在其中的扩散速度更快,固化速度也随之变快。www.sdyuantai.com

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