不干胶的动作原理

No shear strength
Fail under continuous shear
load
黏性与剪力
Viscosity and Shear Strength
• 黏弹性材料
• 非黏性材料
Visco-elastic Materials (e.g. Pressure Sensitive Adhesive 不 乾胶)
Elastic
Solid
软
不乾胶
Pressure Sensitive
韧
Soft
Adhesives
Firm
粘黏 性
Adhesion Properties
内聚力特性
Cohesion Properties
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
adhesive viscosity
– 促进胶的流动性
Accelerates adhesive flow
– 促进胶的 Improve wetting
• 压 力Pressure
– 促进胶的流动性
Accelerates adhesive flow
– 促进胶的
Improves surface wetting
temperature range (-40 to 350 F) •Excellent chemical & UV resistance
In door & •Significantly improved Out door “WETTING” properties
•Excellent bond to LSE plastics
Require dwell time
– 有极高的剪力
– 有优良的剪力
Maximum shear strength
Well balanced shear
properties
黏性和黏弹性
Viscosity and Visco-elasticity
黏性
Viscous
黏弹性
Visco-elastic
弹性 固 体 状
•Good aging characteristics •Fills gap between Acrylic
and Rubber adhesives
In door & •Broad temperature Out door performance
(-100 to 500 F) •Excellent Durability
最大接触面积
Maximum Contact
粗糙的表面
Textured Surface
不乾胶的化学构成
Pressure Sensitive Adhesive
• 橡胶类 Rubber Adhesives
– 天然胶 Natural Rubber – 人造胶 Synthetic Rubber
• 丙烯酸类 Acrylic Adhesives
Substrate
Substrate Adhesive
Substrate
黏性与剪力
Viscosity and Shear Strength
• 低黏性材料
• 高黏性材料
Low Viscous Materials (e.g. Higher Viscous Materials (e.g.
Water 水)
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
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
Polyvinyl Acetate 聚乙烯 Polyethylene 聚苯 Polystyrene 聚丙烯 Polypropylene 聚氟Teflon
表 面 结 构与不乾胶的厚薄度
Surface Texture
薄
Thin Adhesive
有限度的接触
Limited Contact
厚
Thick Adhesive
Non-viscous Materials (e.g. cured adhesives 作用后的 粘黏剂)
– 使用时须施加压力 Require considerable rub-
– 无流动性 No flow characteristics
down pressure
– 无黏性
– 需驻留时间发挥效能
Not sticky
Crosslinking vs Shear
#200 #400 1,000 20
#220 9502, 9505
6,000 4,000
#100 #200MP 10,000+ 10,000+
Increased Crosslinking
Static Shear Area : 0.5?X 1?
Load : 1,000g @ room temp. 500g @ 158 deg. F
Disadvantages •Limited temperature
performance (-20 to 200 F) •Poorer durability •Poorer chemical and U.V. resistance •Limited “WETTING” characteristics •Lower initial bond strength •Limited to HSE materials
• Tie polymer strands together
No crosslinking
Highly crosslinked
Increasing Crosslinking : • Improves temperature resistance • Provides short dwell repositionability on plastics • Increases solvent resistance • Improves die cutting and handling
韧性胶 Firm
软性胶 SБайду номын сангаасft
Adhesion Level
粘黏力
驻留时间 Dwell Time
如何取得最大的接触面积
Maximisation of Contact Area
压力
• 时 间 Time
– 胶需要时间流动For adhesive to flow
• 温 度Temperature
– 高温可以减低胶的黏性 Decrease
• 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
Initial Adhesion No Dwell Time
最终粘黏力 驻留时间:
Ultimate Adhesion 72 小 时/ 70 癈
•Limited chemical and U.V. resistance
•Limited temperature performance (-40 to 250 F)
•High cost
Rubber vs Acrylic Adhesives Bond Build Up
丙烯酸类 Acrylic
Adhesion Level
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
橡胶类 Rubber
粘黏力
驻留时间 Dwell Time
丙烯酸胶的化学
Acrylic Adhesive Chemistry
• 交连结构 Crosslinking • 增粘处理 Tackification • 不同的聚合物基体
Various polymer backbones
Crosslinking
Crosslinking vs Shear
Oil, Honey 油, 蜂蜜)
– 高流动性
– 只需少许压力便可以流动
Flow easily
Require moderate pressure
– 不须施加压力 Do not need rub down
to flow – 低剪力
pressure
Little shear strength
– 无剪力
– 无法持久承受荷重
In door •Effective “WETTING” properties
•High initial bond strength •Good adhesion to various
substrates •Low cost In door & •Excellent durability Out door •Broad performance
• 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
– 纯丙烯酸类 Standard Acrylic – 改良丙烯酸类 Modified Acrylic
• 矽胶类 Silicone Elastomer Adhesives
Rubber
Acrylic (Tackified)
Acrylic (Nontackified)
Silicone
Advantages
软性与韧性的不乾胶
Soft and Firm Adhesives
• 韧性不乾胶 Firm Adhesive
– 较小的初期接触面积
Less immediate contact
– 较低的初期粘黏力
Low initial bond strength
– 须较长的驻留时间
Requires longer dwell time
• 无臭，无味和溶剂 Less odor during use
粘黏力和内聚力
Adhesion and Cohesion
粘黏力Adhesion
存在两种表面之间的力量 Force between dissimilar surfaces
Substrate Adhesive
内聚力Cohesion
材料自身的力量 Internal strength of material
– 避免汽泡的产生
Eliminates trapped air
表面能
Surface Energy
高表面能 High Surface Energy
容易黏接
Easy-to-adhere
低表面能 Low Surface Energy
难以黏接
Hard-to-adhere
金属Metals 聚碳Polycarbonate 聚酯Polyester 聚氯乙烯PVC 聚氨Polyurethane 丙烯酸Acrylic
Tackification
• Adding resins to increase the adhesion to low surface energy materials
No tackifier
Maximum tackifier
Increasing Tackifier: • Increases adhesion • Decreases temperature resistance • Decreases solvent resistance • Increases softness/oozing
• 软性不乾胶 Soft Adhesive
– 良好的初期接触面积
Good immediate contact
– 较高的初期粘黏力
High initial bond strength
– 较短或不须驻留时间
Needs little or no dwell time
软性与韧性的不乾胶
Soft and Firm Adhesives