不干胶的动作原理（医学资料）.PPTVIP

* 不乾胶的定义Definition of PSA 拥有持久的高黏度Aggressively and permanently tacky 应用时只需用手或手指施压Adheres with finger or hand pressure 不需水, 溶剂或加热过程Requires no activation by water, solvent or heat 有牢靠的粘黏力Exerts a strong holding force 有足够的内聚力和弹性Has sufficient cohesiveness and elasticity Pressure Sensitive Tape Council 不干胶的好处Advantages of PSA抯 不须涂布，混合等预处理步骤 Ready to use, no mixing or brushing is required 一贯性的胶量 Consistent amount of adhesive 使用上方便，快捷Less messy than super glue and contact cement 可以模切成各种形状 Can be die cut into specific shapes 持久的黏弹性可以避免脆化，断裂等现象Stays viscoelastic which eliminates brittle fracture possible with epoxies, hot melts and cyanoacrylates 无臭，无味和溶剂 Less odor during use 粘黏力和内聚力Adhesion and Cohesion 内聚力Cohesion 材料自身的力量 Internal strength of material Adhesive Substrate Substrate Adhesive Substrate Substrate 粘黏力Adhesion  存在两种表面之间的力量 Force between dissimilar surfaces 黏性与剪力Viscosity and Shear Strength 低黏性材料Low Viscous Materials (e.g. Water 水) 高流动性Flow easily 不须施加压力Do not need rub down pressure 无剪力No shear strength 高黏性材料Higher Viscous Materials (e.g. Oil, Honey 油, 蜂蜜) 只需少许压力便可以流动Require moderate pressure to flow 低剪力Little shear strength 无法持久承受荷重Fail under continuous shear load 黏性与剪力Viscosity and Shear Strength 黏弹性材料Visco-elastic Materials (e.g. Pressure Sensitive Adhesive 不乾胶) 使用时须施加压力Require considerable rub-down pressure 需驻留时间发挥效能Require dwell time 有优良的剪力Well balanced shear properties 非黏性材料Non-viscous Materials (e.g. cured adhesives 作用后的粘黏剂) 无流动性No flow characteristics 无黏性Not sticky 有极高的剪力Maximum shear strength 黏性和黏弹性Viscosity and Visco-elasticity 粘黏 性Adhesion Properties 内 聚 力 特 性Cohesion Properties 软Soft 韧Firm 不 乾 胶Pressure Sensitive Adhesives 黏 性Viscous 黏 弹 性Visco-elastic 弹性Elastic 固 体 状 Solid 不 乾 胶 的 运 作 原理How PSA Bonds ? 不 乾 胶 具 有 流 动 性, 能 与 背 材 紧 密 接 合Adhesive must FLOW to CONTACT substrate 不乾胶与背材间的相互作用Adhesive - Substrate INTERACTION 初 期 与 最 终 粘 黏 力Initial and Ultimate Adhesion 初 期 粘 黏 力 无 驻 留 时 间 Initi