有機改質黏土應用於螢光粉分散劑及封裝流變助劑

Organically Modified Clays as Dispersing Agents and Rheology Modifying Agents for Facilitating Epoxy Encapsulation of LED Lights

蔡育庭(Yu-Ting Tsai)

指導教授 ： 林江珍

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10181

摘要

為解決業界白光二極體 (white light-emitting diode, WLEDs) 於環氧樹脂封裝過程中，螢光粉易沉降之現象為主要研究。本實驗設計一新型有機改質黏土，藉由高分子型有機胺鹽與奈米黏土進行離子交換所得之，其可均勻分散於酸酐型環氧樹脂中。有機改質黏土於樹脂中屬於非牛頓流體具有剪切稀力之特性，可作為新型流變助劑與增稠劑，其能有效避免螢光粉於樹脂加熱固化過程中沉降，成功克服高密度無機顆粒材料於高分子材料中不易分散且易沈澱之問題。系統於高剪切力低黏度 (約250 cP) 下，螢光粉能夠均勻分散於樹脂中，幫助螢光粉均勻分散於樹脂中，扮演分散劑之角色；然當樹脂靜置後，系統則瞬間回至高黏度 (約1,500 cP)，有效避免螢光粉之沉降現象發生。
合成之有機改質黏土經 X-光散射 (X-ray Diffraction, XRD) 鑑定後，黏土層間距由原始之 12 Å 達 52 Å，證實高分子型有機胺鹽與鈉離子交換進入黏土層間，得到一插層型有機改質黏土；利用流變儀則可分析有機改質黏土於樹脂中之流體性質與黏度變化，最後利用掃描式電子顯微鏡 (Scanning Electron Microscope, SEM) 觀察螢光粉於封裝樹脂中之分散情形。

關鍵字

有機黏土 ； 螢光粉 ； 分散劑 ； 流變助劑 ； 發光二極體

並列摘要

We discovered a new class of polyetheramine-modified organoclays enabling the homogenously dispersing inorganic phosphorescent phosphor powder (Y3Al5O12; yttrium aluminum garnet; YAG) in the epoxy encapsulation of light-emitting diode (LED) devices. The organoclays were prepared from the ionic exchange reaction of sodium montmorillonite (Na+-MMT) with alkyl-amines (C12, C14 and C18 fatty amine) and various polyether-amines including poly(oxypropylene) (POP) and poly(oxyethylene) (POE) diamines, and characterized by using X-ray diffraction (XRD). The organoclays were screened for the function of dispersing YAG in the two-component epoxy system involving an anhydride curing agent and an aliphatic resin. The organoclays from the POP-diamines intercalation, MMT-POP2000, at the basal spacing structure of 52 Å (in reference to 12 Å for Na+-MMT), was found to be effective for homogenizing YAG in the epoxy. With the addition of 1.0 wt% of MMT-POP2000, the viscosity of the epoxy system was increased up to 1,500 cP at standing but decreased to 250 cP under high shear force, indicating a strong non-Newtonian shear-thinning behavior. As a result, the micrometer size of YAG particles (13 ~ 14 μm) was well distributed in the epoxies without aggregation during the curing process owing to the high viscosity. The behavior of organoclays as the thickening agent was investigated and applied to the fabrication of white LED illumination by emitting blue light then mixing yellow light of YAG particles. Furthermore, the homogeneous dispersion of YAG particles in cured epoxy was confirmed by scanning electron microscope (SEM).

並列關鍵字

organoclays ； phosphorescent phosphor powder (Y3Al5O12 ； Yttrium Aluminum Garnet ； YAG) ； dispersant ； rheology modifying agents ； light-emitting diode (LED)

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