鍍鋅鋼板用水性聚氨酯塗層的防護性測試及探討

A Study of the Anticorrosion Properties of Waterbrone Polyurethane Coatings on Galvanized Steel Sheets

謝欣盛(Hsin-Sheng Hsieh)

指導教授 ： 戴宏哲

義守大學/理工學院/化學工程學系暨生物技術與化學工程研究所/碩士(2015年)

https://doi.org/10.6343/ISU.2015.00142

摘要

本研究主要於水性聚氨酯中引入不同劑量矽烷偶合劑、二氧化矽與架橋劑進行改質，並將水性聚安酯塗料塗佈於鍍鋅鋼板表面上，並探討其防護性。
第一部分是於水性聚氨酯中引入矽烷偶合劑 ：3－胺基丙基三乙氧基矽烷(3-aminopropyltrimethoxysilane,APTMS)，於室溫固化成膜探討其含膠量，ATPMS 的目的是將 WPU 顆粒外圍的(－COOH)基團與基材連接，使其增強有機相與無機相的表面附著力，作為接合劑與無機相鍍鋅鋼板連接，塗佈後於室溫固化後進行高溫交聯，其中隨加入不同劑量的 APTMS 進行一系列的防護性測試。
第二部分是引入二氧化矽(SiO2)，二氧化矽已在很多文獻上證明可改善 WPU 的耐水性、硬度、耐磨性等特性，此部分同樣於水性聚氨酯中引入矽烷偶合劑(APTMS)，並於引入矽烷偶合劑(APTMS)後再加入二氧化矽(SiO2)，於室溫固化成膜探討其含膠量，並塗佈於鍍鋅鋼板，並於室溫固化後進行高溫交聯，其中以不同劑量的 APTMS加入不同劑量的二氧化矽以測試其防護性。
第三部分則是以 WPU 加入ATPMS 與SiO2後，額外引入架橋劑於系統中，所選用的架橋劑為碳化二亞胺(Carbodiimide)型的 XL－29SE，利用多官能團的小分子結構與分子鏈之間進行連接，提供架橋功能，以改善耐水性、耐磨性、附著力與抗溶劑性等，一樣於室溫固化成膜探討其含膠量，並塗佈於鍍鋅鋼板上於室溫固化後進行高溫交聯，以進行含膠量測試、粘著性測試、硫酸銅測試、鉛筆硬度測試、接觸角測試、鹽霧測試等實驗測試。
在含膠量測試中顯示，隨 APTMS 引入量增加，由純 WPU 的0%可提高至最高46.71%，額外引入SiO2 可使含膠量上升至60.65%，並在XL－29SE 的作用下可小幅提升至61.96%，在黏著力方面也表現出相當不錯的性能，薄膜的硬度由最初的 6B，隨APTMS 的引入提高到 HB，在SiO2與XL－29SE 的作用下可到達 H，而薄膜在阻隔硫酸銅的防護性，由阻隔時間15分可隨系統一中 APTMS 的引入最高可阻隔到25分，於引入 SiO2 的系統二最高可阻隔到30分，於引入 XL－29SE 的系統三最高可阻隔到35分，接觸角也由純 WPU 的70.8°，由系統一中 APTMS 的加入，提升到了75.06°，而在系統二中除 APTMS 的加入外額外再加入SiO2 ，接觸角提升到了77.2°，最後在架橋劑 XL－29SE 引入下，接觸角最高提升至78.42°，在鹽霧測試方面純 WPU 由24hr 開始受到了鹽霧的腐蝕，隨著第一系統中 APTMS 與系統二中引入的SiO2，隨引入量的增加，鋼板上出現黑點的時間有延後的情況，其防護效果皆有小幅提高的現象。

關鍵字

水性聚氨酯 ； 矽烷 ； 二氧化矽

並列摘要

The purpose of this research is to study the corrosion protection effectiveness of waterborne polyurethane (WPU) coatings modified with a silane, nano-SiO2 particles and a crosslinking agent on galvanized steel sheets.
In the first part, 3-aminopropyltrimethoxysilane (APTMS), was used to bind the WPU particles and the metal substrate by reacting simultaneously with the COOH moiety of WPU and the pedant OH group on metal surface. The silane was used to promote the adhesion between the organic polymer and the inorganic galvanized steel sheet. The coatings were dried at room temperature and then cured at a high temperature. The coatings with various amounts of APTMS were then subjected to a series of corrosion protection tests.
In the second part, additional nano-SiO2 particles were added to the WPU/APTMS mixtures. SiO2 particles were reported in many papers to be able to improve moisture resistance, hardness and abrasion resistance of WPU. SiO2 particles were added after mixing WPU with APTMS. The fabrication steps and tests were similar to those for WPU/TMPMA mixtures.
In the third part, a carbodiimide crosslinker, XL-29SE, was further added into the WPU/APTMS/SiO2 mixtures. The crosslinker was to promote the crosslink density to further improve moisture resistance, abrasion resistance, adhesion and solvent resistance. The fabrication steps and tests were similar to those for the above mixtures.
The gel content results show that the highest gel content value reaches 46.7% at the highest APTMS dosage, the value increases to 60.7% with the further addition of SiO2, then the value further increases to 62% with the further addition of XL-29SE. The pencil hardness value for the WPU coating is 6B, it increases to HB with the addition of APTMS, it further increases to H with the addition of SiO2 and/or XL-29SE. In the aqueous copper sulfate solution drop tests, the penetration time is 25 min for the WPU/APTMS coating, it improves to 30 min for the WPU/APTMS/SiO2 coating, it further improves to 35 min for the WPU/APTMS/SiO2/XL-29SE coating. In the contact angle tests, the value is 70.8° for WPU, 75.1° for WPU/APTMS, 77.2° for WPU/APTMS/SiO2 and 78.4° for WPU/APTMS/SiO2/XL-29SE. The salt spray tests show that the surface of WPU-coated sheet deteriorate after 24h, while the surfaces of WPU/APTMS- and WPU/APTMS/SiO2-coated sheets show little sign of deterioration after 72h.

並列關鍵字

waterborne polyurethane ； silane ； SiO2

參考文獻

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