以水性聚胺酯為基底引入壓克力多元醇及二氧化矽 合成可熱交聯之抗腐蝕塗料

Abstract

本研究是以水性聚胺酯的合成系統為骨幹，調整合成方法和配方並引入自行合成的壓克力型多元醇以製備不同種類的機能性加熱成膜型表面保護塗料。所合成的塗料分為外加架橋劑型和可自交聯型兩個種類；外加架橋劑型即先行合成水性PU乳液，再直接加入和親水離子基能夠在加熱後進行反應的架橋劑形成一液型水性塗料；使用的架橋劑共有兩種，一種是具有可快速成膜特性的多官能團碳化二亞胺型架橋劑XL-29SE；一種是可將無機SiO2引入膜中的有機矽烷GPTMS；可自交聯型則是改變合成方法將SiOH基團直接接在PU顆粒外圍，具有不須外加架橋劑即可自行交聯的特性。並對成型薄膜進行各式測試以評估表面保護能力。 實驗的第一部分合成壓克力型多元醇並引入水性PU之合成系統，製備須外加架橋劑的水性PU，討論壓克力多元醇引入對乳液分散粒徑和Zeta potential造成的改變，以及對薄膜硬度和接觸角造成的影響。 實驗的第二部分將兩種不同的架橋劑加入水性PU中形成一液型塗料，XL-29SE是以二亞胺官能基團和親水離子基反應交聯，可快速成膜；GPTMS則是先以矽烷官能基團之間在低溫進行sol-gel反應轉化成兩端為環氧基的具有架橋功能的單元，再升溫進行開環反應。之後對所成薄膜進行熱性質、硬度、接觸角和表面保護能力等測試，比較兩種架橋劑的不同表現並探討成因，以及討論以小分子架橋劑的方式將無機的SiO2引入高分子塗料中的可行性。 第三部分和前兩部分合成水性PU塗料的策略不同，在合成過程中使用過量的異氰酸鹽，預聚物乳化形成顆粒後再使用帶有一級胺基的有機矽烷和剩餘的異氰酸基反應，使合成的水性PU表面即帶有Si-OH基團。所成水性塗料塗佈完後再經過低溫sol-gel和高溫乾燥兩段式加熱成膜。之後對所成薄膜進行熱性質、硬度、接觸角和表面保護能力等測試，和前一部份結果比較兩種無機SiO2的引入方法所造成的差異。

In this research, two kinds of water-borne polyurethane dispersion which can be applied as an anti-corrosion coating on galvanized steel sheets by thermal treatment have been prepared by adjusting the synthesis process and composition and introducing of polyacrylate. The paints can be divided into two types, the one need additive adding of crosslink agent before using and the one with the ability of self-crosslinking. The are two kinds of crosslinking agents been used in the first type, XL-29SE, a kind of carbodiimide with multi-functional group which has the advantage of fast curing and GPTMS, a kind of silane which can introduce the inorganic SiO2 group into coating. The second type with the ability of self-crossinking is prepared by changing the synthesis process to let SiOH group directly sticked to the surface of the particles. The first part of my research is about the preparing and introducing into polyurethane system of polyacrylate , and the synthesis of water-borne polyurethane dispersion. By the characterizing of the particle size and zeta potential of the dispersion、the hardness and contact angle of the film to find out the effect of the introducing of polyacrylate. In the second part of my research, two kinds of crosslinking agents were added into the WPU forming two different one-part paints. In XL-29SE series , the film was forming by the fast crosslink reaction of diimide group and carboxylic group, another end in GPTMS series the film was forming by two-stage thermo treating including low V temperature sol-gel reaction to form a unit with epoxy group on both end which indeed the crosslinkable part, and high temperature ring-opening crosslink reaction. In the second section of this research, we develop new liquid coatings mixed by two various crosslink agents with WPU. XL-29SE, which can reduce the time for film formation, reacts with hydrophilic functional group via diimide group. By contrast, GPTMS, via silanol group, undertakes sol-gel reaction in low temperature and forms epoxy groups at both ends. The epoxy groups can serve as a crosslinker in high temperature by an ring-opening reaction. Therefore, we compare the characteristic (e.g., thermal property, hardness, contact angle, and protective ability) of thin films from two different mechanisms to demonstrate the effect of two crosslinkers, and discuss the possibility of the addition of inorganic part by small molecular crosslinker(i.e., SiO2) in polymer coating. In the third section, we use excess NCO group to form the pre-polymer, after the emulsion process we add a kind silane with primary amine group in one end to react with the remained NCO group, forming a particle with silanol group on the surface. After the synthesis of the paint, we form thin films through two steps, sol-gel in low temperature and dry in high temperature. We test the characteristic of thin films and compare these two inorganic methods mentioned in the second section.