44947226 adhesive bonding

MIL-HDBK-691B 12 Match 1987 SUPERSEDING M IL-HDBK-691A 17 May 1965 MILITARY STANDARDIZATION HANDBOOK ADHESIVE BONDING NO DELIVERABLE DATA REQUlREO B Y THIS DOCUMENT AMSC N/A CiSTRIBL'TXOS STlTEYfST A ~ p p r o v e dfor p ~ ~ b l irce l e a s e ; distribution- t unl i n i r e d Department of Defense Washington, D.C MIL-HDBK-691B Adhesive Bonding Date This standardization handbook was developed by the Department of Defense in accordance with the established procedures This publication was approved on the military standardization handbook series for printing and inclusion in This handbook provides basic and fundamental information on adhesives and related bonding processes for the guidance of engineers and designers of military materiel It should provide valuable information on most of the factors that must be considered in adhesive bonding, and should be of value in the preparation of specifications, including process specifications The handbook is not intended to be referenced in purchase specifications, except for informational purposes, nor shall it supersede any specification requirements Every effort has been made to reflect the latest information on adhesives and adhesive bonding and closely related techniques It is the intent to review this handbook periodically to insure its completeness and accuracy, Beneficial comments (recommendations, additions, or deletions) and any pertinent data which may be of use in improving this document should be addressed to: Director, Army Materials Technology Laboratory ATTN: SLCMT-MSE, Watertown, MA 02172-0001, by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document, or by letter 4, , Thia handbook i s one of a group which covere m e t a l l i c a n d w n m e t a l l i c m a t e r i a l s used i n t h e design and conetruction of m i l i t a r y equipment The purpose of these handbooks i e t o provide up-to-date i n f o m a t i o n and design d a t e of d i r e c t ueefulneae t o engineers and deeignere of m i l i t a r g equipment The i n t e n t of t h i a handbook i a t o provide d e t a i l e d information ueeful t o engineera and designera concerned with adhesive bonding of m i l i t a r y materiel The e a r l i e r versions of t h i e document concentrated on fundamental guidelines, but i t was f e l t t h a t such information uas too general t o be useful Coneequently, the handbook has been completely r e w r i t t e n and expanded Even with the considerable amount of i n f o m a t i o n given i n t h i e handbook and i n o t h e r eourcee, i t is nevertheless reconmended t h a t deaignere and engineere with adhesive bonding problema seek the aeeiatance of a q u a l i f i e d adheeives technologis t The p r o p e r t i e s and d a t a presented i n t h i s handbook come from many sources and ere not intended t o be ueed f o r purpose8 of providilrg mamafacturiag o r procurement 8pecifications Such requirements are adequately covered bg applicable s p e c i f i c a t i o n s Comments on this handbook a r e invited This document was prep8red f o r the A r m y Materials Technology Laboratory, (NTL), by the DoD P l a s t i c s Technical Evaluation Center, (PLAsTEC) , U.S Army Awament Reeearch, Development end Engineering Center (ARDEC) a t Dover, N J 07801-15001 U.S Foreword Paragraph IWTRODUCTION TO A D M l V Y , BONDING I Definition of adhesive bonding Functions of adhesives Advantages and disadvantwes of adhesive bonds Ad ventages Disadvantages Theories of adhesion Mechanical theory Adsorption theory E l e c t m ~ t a t i ctheory Diffusion theory Yealc-boundary l a y e r theory Requirements f o r a good bond Cleanliness YettiSolidification Adhesive choice J o i n t design Mechanism of bond f a i l u r e Basic adhesive materials c l a e s i f i c a t i o n Function Major types Thermosetting adhesives Themoplaatic adhesives Elastomeric adhesives Adheeive a l l o y s Mode of a p p l i c a t i o n end s e t t i n g Physical form Cost S p e c i f i c adherends o r a p p l i c a t i o n s Adhesive compoeition Baae o r binder Hardener Fatalyet Solveats Diluent Pillere C a r r i e r s o r reinforcements a Adhesive b n d i a g proceee Reference8 ~ Basic p r i n c i p l e s Types of s t r e s s Compression JOINTDESIGN iii COIPTEtITS Continued Shear Tensile Peel Cleavage Hethods of *proving joint efficiency J o i n t deeign c r i t e r i a Typical Joint deeigne J o i n t s f o r f l a t adherends Buttjointa Lapjoints Strap j o i n t s Peelin$ of adhesive j o i n t s Stiffening j o i n t s Cylindrical Joint8 Angle and comer j o i n t s P l a e t i c and elastomer joint8 Flexible p l a a t i c and elastomers Rigid p l a a t i c e Wood j o i n t s Metal j o i n t s J o i n t s combining different adherend types J o i n t s with adherende differimg i n r i g i d i t y dointe with adherende differing i n coefficient of thermal expaneion Stresa analyeis General principles Theoretical analyses of etreseea and s t r a i n s Experimental analyses Failure analyses Hethode Volkersen Coland and Reiesner Fomet product8 laboratory review References * ~ General diecueeion Similar aubstretee Poroue materials Nonporoue materials Diaeimilar subatratee Poroue materials Nonporoue materials References COWTENTS Continued Page STRUCTURAL ADHESIVE TYPES & SELECTION OUXDglIIES General discussion C l a s s i f i c a t i o n of SHE ,handbook Chemically r e a c t i v e types Catalytic plural c chemical cure Epoxy adhesives Phenolic adhesives Reeorcinol-formald Polyesters P03yaulfides Polyurethanes C a t a l y t i c p l u r a l components moiature c u r e Silicones Urethanes Other adhesives Heet-activated eystem (one-part system) Poly beneimidazoles (PBI) and polyimides (PI) Epoxies Nylon Phenolics Polyvinyl a c e t e l s Urethanes Evaporetion or diffusion adhesives Natural rubber Peclaimed rubber Synthetic rubbers l i t r i l e rubber Neoprene o r polychloroprene Butyl x u b k r Stywne-butediene rubber Phenolice Urethanes Miscellaneous resins ~ ' W a t e ~ b a e e deyetems Natural rubber ~ Reclaimed rubber Synthetic rubbers Vinyl Resins A c r y l i c ~ l4iecellaneoua Resins 47 47 47 47 47 47 48 49 49 49 49 50 51 51 52 52 52 CONTENTS Continued Additional claaeificationa ~dhesive/eealante Types of eealants Hardening types lon-hardening typea primer^ Microencapauleted edbesivee Electrically and tbemally conductive adheeives Electrically-conductive adheeivee Thermally-conduc t i v e adhesive8 Preaired froeeo adheeivee Anaerobic sdheeives Paet eet tiag adheeivee Elaetomeric edheaivee Natural glues Vegetable glues Starch DertrLns Soyabean glue Boein Clues of animal o r i g i n Casein glue Blood albumen (blood gluee) Animal gluee Fish glue8 Shellac Inorganic glues Soluble s i l i c a t e s Phoephate cementa Basic s a l t (sore1 cemeota) Litharge cemente Sulphur cementa Hydreulic cement6 Factor8 t o be coaeidered i n adheeive selection Adheeive subetratee (adberende) Service requirenente * requireneate life Uorking life time) (taok-fne Curing Coat requirements Time-related Stomi8e (ehelf l i f e ) (pot l i f e ) Tack r w e (open time) (open tack (tack time) time) Aeeembly time the COMTEflTS Continued Dryiagtime J o i n t conditioning time ( j o i n t aging time) S e t t i n g time E a r l i e s t handling time Adhesives f o r metals Adhesives f o r p l a s t i c s Solvent cementing Adhesive bonding Thennal w e l d i n g techniques Direct heetiag method8 Hot-platewelding Hot-gas welding Heated-tool w e l d i n g Radiant-heat welding Reeietance-wire welding Molten-polymer (extruded bead) s e a l i n g Indirect h e e t i w methods D i e l e c t r i c bonding (high frequency bonding) Induction heating (electromagnetic bonding) Ultraaonic welding Ultrasonic adhesive bonding Spin o r f r i c t i o n welding Adhesives f o r elastomers Vulcanized elastomers ~ n v u l c a n i ~ eelastomers d Adheeivee f o r wood Adheeivea f o r g l a a s Checkliat f o r adhesives s e l e c t i o n References ADHEREHD General diecuesion Primers Surface preparation Importance of surface preparatiom Genera3 cleaning methods Solvent uipiw Vapor degreaeing Abrasive cleaning Chemical cleaning ( a l k a l i n e c l e a n i q ) Water p u r i t y Other cleaning methods Chenical e t c h SURFACE PREPARATION viii Page WR'E8RTS Continued Page Combined cleaning methods Activated-gaa eurface treatment of polymer Evaluetion o f cleaned p a r t s before and after bonding Watercbreaktest Contact angle test Mode of f a i l u r e of adheaive j o i n t Surface expoeure time S p e c i f i c s u r f a c e treatments Metals General diecuesf on Aluminum and e l l o y a Beryllium Brass Bronze Cadmium Copper and a l l o y s Magnesium and a l l o y s Nickel and a l l o y e S t e e l (mild carbon) i r o n Steel (staimlees) Tin T~taniumaod alloys Tungsten and a l l o y s Zinc and alloys Plated metals Weldbonding Aluminum T i taniun Plastics General diecueeion Thermoplaetice Acetal copolymer Acetal homopolymer Acrylanitrile-butadiane-styrene Belluloefcs Ethylene-tetrafluoroethylene copolymer Ethylene-vinylacetate Fluorinated etbylene propylene lonomere Nylon (polyamide) Perf luoroelkoxy resin Pheaylene oxide-baaed r e s i n s Polyargl e t h e r Polyaryl s u l f o n t Polycerbonate Polychlorotrif~uoroethylene 120 122 124 124 124 125 125 126 126 126 126 131 135 135 135 136 1% 140 140 142 144 144 146 146 147 148 148 149 150 150 150 150 151 152 153 153 153 154 154 154 155 155 155 156 157 19 APPENDIX GLOSSARY OF TERMS The d e f i n i t i o n s g i v e n i n t h i s Appendix a r e t a k e n from a number o f s o u r c e s , which have been c i t e d They i n c l u d e t h e l a t e s t ASTM Committee D-14 and IS0 TC 61 definitions I n some c a s e s s e v e r a l O e f i n i t i o n s a r e given A few d e f i n i t i o n s found i n l i t e r a t u r e s o u r c e s have been used t o supplement o r r e p l a c e more complicated d e f i n i t i o n s from g l o s s a r i e s A-Stage An e a r l y s t a g e i n t h e r e a c t i o n of c e r t a i n t h e e g o s e t t i n g r e s i n s i n which t h e m a t e r i a l i s f u s i b l e and s t i l l s o l u b l e i n c e r t a i n l i q u i d s Sometimes r e f e r r e d t o as Resol ( s e e a l s o B-stage and C - s t a g e ) ( ) a b h e s i v e A m a t e r i a l which i s a d h e s i v e - r e s i s t a n t and a p p l i c a b l e a s a nonsticking s u r f a c e coating; r e l e a s e agent (2) f a d h e r e , v To cause two s u r f a c e s t o be h e l d t o g e t h e r by a d h e s i o n (q.v ) ( ) adherence o - m The s t a t e i n which two s u r f a c e s a r e h e l d t o g e t h e r by i n t e r f a c i a l adherend A body which i s h e l d t o a n o t h e r body by an a d h e s i v e ( a narrower term t h a n s u b s t r a t e , q.v.) ( ) a d h e s i o n The s t a t e i n which two s u r f a c e s a r e h e l d t o g e t h e r by chemical, o r p h y s i c a l f o r c e s , o r both, with t h e a i d of a n adhesive ( ) a d h e s i v e A s u b s t a n c e c a p a b l e of h o l d i n g m a t e r i a l s t o g e t h e r by s u r f a c e a t t a c h m e n t Adhesive is t h e g e n e r a l term and i n c l u d e s , among o t h e r , cement, g l u e , mucilage, and p a s t e (q.v.) A l l of t h e s e terms a r e used i n t e r c h a n g e a b l y a d h e s i v e , a n a e r o b i c An a d h e s i v e t h a t c u r e s spontaneously i n t h e absence of oxygen, t h e c u r i n g being i n h i b i t e d by t h e presence of oxygen and c a t a l y s e d by m e t a l l i c ions (3) adhesive, cold-setting ( 0 ~ ) (1) An a d h e s i v e t h a t s e t s a t t e m p e r a t u r e s below ~ a d h e s i v e , c o n t a c t An a d h e s i v e t h a t i s a p p a r e n t l y dry t o t h e touch and which w i l l a d h e r e t o i t s e l f i n s t a n t a n e o u s l y upon c o n t a c t ; a l s o c a l l e d c o n t a c t bond adhesive ( ) ,An a d h e s i v e t h a t i s a p p l i e d t o both adherends and allowed t o become d r y and t h e n develops a bond when t h e adherends a r e brought t o g e t h e r w i t h o u t s u s t a i n e d p r e s s u r e (3) a d h e s i v e , d i s p e r s i o n ( o r emulsion) A two-phase system w i t h one phase ( t h e a d h e s i v e m a t e r i a l ) i n a l i q u i d suspension (3) a d h e s i v e , e n c a p s u l a t e d An a d h e s i v e i n which t h e p a r t i c l e s o r d r o p l e t s of one of t h e r e a c t i v e components a r e e n c l o s e d i n a -p r o t e c t i v e f i l m ( m i c r o c a p s u l e s ) t o p r e v e n t c u r e u n t i l t h e f i l m i s d e s t r o y e d by s u i t a b l e means (3) adhesive, film An adhesive i n f i l m form, with o r without a c a r r i e r , use-ans of h e a t and pressure ( ) The main advantage i s uniformity of g l u e l i n e thickness adhesive, g a p f i l l i n g An adhesive s u b j e c t t o low shrinkage i n s e t t i n g , employed a s a s e a l a n t ( ) adhesive, heat-activated A dry adhesive t h a t i s rendered tacky o r f l u i d by a p p l i c a t i o n of h e a t , o r h e a t and pressure, t o the assembly ( ) ( ) adhesive, heat-sealing A thermoplastic f i l m adhesive which i s melted between t h e adherend s u r f a c e s by h e a t a p p l i c a t i o n t o one o r both of t h e a d j a c e n t adherend s u r f a c e s ( ) A thermoplastic adhesive t h a t i s applied i n a molten adhesive, hot-melt s t a t e and forms a bond on cooling t o a s o l i d s t a t e adhesive, h o t - s e t t i n g ( 0 ~ ) (1) An adhesive t h a t s e t s a t temperatures above 680F adhesive, intermediate-temperature s e t t i n g An adhesive t h a t s e t s i n the temperature range from 870 t o 211°F (310 t o 9 ~ ) (1) adhesive, l a t e x An emulsion of rubber o r thermoplastic rubber t o water ( ) adhesive, one-component An adhesive m a t e r i a l i n c o r p o r a t i n g a l a t e n t hardener o r c a t a l y s t a c t i v a t e d by h e a t Usually r e f e r s t o thermosetting m a t e r i a l s , but a l s o d e s c r i b e s anaerobic, hot-melt adhesive, o r those dependent on s o l v e n t l o s s f o r adherence ( ) Thermosetting one-component adhesives r e q u i r e heat t o cure adhesive, pressure-sensitive An adhesive which, i n the dry s t a t e , is a g g r e s s i v e l y and permanently tacky a t room temperature and f i r m l y adheres t o a v a r i e t y of d i s s i m i l a r s u r f a c e s upon c o n t a c t without the need f o r more than f i n g e r o r hand pressure adhesive, room-temperature s e t t i n g An adhesive t h a t s e t s i n t h e temperature range from 680 t o 860F (200 t o 300C) adhesive, solvent -ev An adhesive having a v o l a t i l e organic l i q u i d a s a excludes water-based adhesives ( ) adhesive, solvent a c t i v a t e d A d ~ adhesive y o r adherend t h a t i s rendered t a c k y j u s t p r i o r t o use by a p p l i c a t i o n of a solvent ( ) adhesive, s t r u c t u r a l An adhesive of proven r e l i a b i l i t y i n engineering s t r u c t u r a l a p p l i c a t i o n s i n which t h e bond can be s t r e s s e d t o a high proportion of i t s maximum f a i l i n g load f o r long periods without f a i l u r e (3) adhesive, two-component An adhesive supplied i n two p a r t s which a r e mixed before a p p l i c a t i o n ( ) Such adhesives u s u a l l y cure a t room temperature A term t h a t i s sometimes used a s a synonym f o r adhesive, warm-setting intermediate-temperature-setting adhesive (q.v ) ( ) amylaceous, a d j - Pertaining t o or of, t h e n a t u r e of s t a r c h ; s t a r c h y * ( ) ( f o r a d h e s i v e ) A group of m a t e r i a l s o r p a r t s , i n c l u d i n g a d h e s i v e , which h a s been placed t o g e t h e r f o r bonding, o r which h a s been bonded t o g e t h e r (1)(3) -0 a u t o c l a v e A closed c o n t a i n e r which p r o v i d e s c o n t r o l l e d h e a t and p r e s s u r e conditions (2) B-stage An i n t e r m e d i a t e s t a g e i n t h e r e a c t i o n of c e r t a i n t h e r m o s e t t i n g r e s i n s i n which t h e m a t e r i a l s o f t e n s when h e a t e d t o a rubbery s t a t e and s w e l l s when i n c o n t a c t with c e r t a i n l i q u i d s , b u t may not e n t i r e l y f u s e o r d i s s o l v e i n some of t h e s o l v e n t s which w i l l d i s s o l v e r e s i n s i n t h e A-stage The r e s i n i n a n uncured t h e r m o s e t t i n g a d h e s i v e i s u s u a l l y i n t h i s s t a g e Sometimes r e f e r r e d t o as R e s i t o l ( ) ( ) backing The f l e x i b l e s u p p o r t i n g m a t e r i a l f o r an adhesive P r e s s u r e s e n s i t i v e a d h e s i v e s a r e commonly backed w i t h p a p e r , p l a s t i c f i l m s , f a b r i c , o r m e t a l f o i l ; h e a t - c u r i n g t h e r m o s e t t i n g a d h e s i v e s a r e o f t e n supported on g l a s s c l o t h backing bag molding ( b l a n k e t molding) A method of molding o r bonding i n v o l v i n g t h e a p p l i c a t i o n of f l u i d p r e s s u r e , u s u a l l y by means of a i r , steam, w a t e r o r vacuum, t o a f l e x i b l e c o v e r which, sometimes, i n c o n j u n c t i o n with t h e r i g i d d i e , completely e n c l o s e s t h e m a t e r i a l t o be bonded ( ) bag, vacuun A f l e x i b l e bag by which p r e s s u r e may be a p p l i e d t o an assembly i n s i d e t h e bag by means of e v a c u a t i o n of t h e bag (3) b i n d e r A component of an a d h e s i v e composition t h a t i s p r i m a r i l y r e s p o n s i b l e f o r t h e adhesive f o r c e s which h o l d two bodies t o g e t h e r b i t e , n The p e n e t r a t i o n o r d i s s o l u t i o n of adherend s u r f a c e s by an adhesive (2) - body The c o n s i s t e n c y of a n a d h e s i v e which i s a f u n c t i o n of v i s c o s i t y , p l a s t i c i t y , and r h e o l o g i c a l f a c t o r s ( ) , bond, v bond l i n e The union o r j o i n i n g o f m a t e r i a l s by adhesives ( , modified) See g l u e l i n e bond s t r e n g t h The u n i t l o a d ( f o r c e ) s u p p l i e d i n t e n s i o n , f l e x u r e , p e e l , impact, c l e a v a g e , o r s h e a r , r e q u i r e d t o break assembly, w i t h f a i l u r e o c c u r r i n g i n o r n e a r t h e plane of t h e interface) The term adherence (q.v.) i s f r e q u e n t l y used i n s t r e n g t h ( , modified]bond, s t r u c t u r a l See s t r u c t u r a l bond compression, a n adhesive bond ( t h e p l a c e of bond C-stage The f i n a l s t a g e i n t h e r e a c t i o n of c e r t a i n t h e r m o s e t t i n g r e s i n s i n which t h e m a t e r i a l is r e l a t i v e l y i n s o l u b l e and i n f u s i b l e C e r t a i n t h e r m o s e t t i n g r e s i n s i n a f u l l y cured a d h e s i v e l a y e r a r e i n t h i s s t a g e Sometimes r e f e r r e d t o as R e s i t e ( ) c a t a l y s t A s u b s t a n c e t h a t markedly speeds up t h e c u r e o f an adhesive when added i n minor q u a n t i t y , a s compared t o t h e amounts of t h e primary r e a c t a n t s ( ) M a t e r i a l which promotes c r o s s l i n k i n g i n a polymer o r a c c e l e r a t e s drying (2 cement, n (See a d h e s i v e and s o l v e n t cement ) cement, v To bond w i t h a cement A synonym f o r adhesive cohesion The s t a t e i n which t h e p a r t i c l e s of a s i n g l e s u b s t a n c e a r e held t o g e t h e r by primary- o r secondary-valence f o r c e s I n a d h e s i v e s , cohesion i s t h e s t a t e i n which t h e p a r t i c l e s of t h e a d h e s i v e o r adherend a r e h e l d together (1) c o l l a g e n The p r o t e i n d e r i v e d from bone and s k i n used t o p r e p a r e animal g l u e and g e l a t i n ( ) colophony The r e s i n o b t a i n e d from v a r i o u s s p e c i e s of pine t r e e s ( ) c o n t a c t bonding The d e p o s i t i o n o f c o h e s i v e m a t e r i a l s on b o t h adherend s u r f a c e s and t h e i r assemby under p r e s s u r e (2) copolymer See polymer copolymerization core - See p o l y m e r i z a t i o n The honeycomb s t r u c t u r e used i n sandwich-panel c o n s t r u c t i o n c o r r o s i o n The chemical r e a c t i o n between t h e adhesive o r contamination and t h e adherend s u r f a c e s , due t o r e a c t i v e components i n t h e a d h e s i v e f i l m , l e a d i n g t o d e t e r i o r a t i o n of t h e bond s t r e n g t h ( ) coverage The s p r e a d i n g power of an a d h e s i v e o v e r t h e s u r f a c e a r e a of t h e ,adherend ( , modified) c r o s s - l i n k i n g ( c r o s s l i n k i n g ) The union of a d j a c e n t molecules of uncured a d h e s i v e ( o f t e n e x i s t i n g as long polymer c h a i n s ) by c a t a l y t i c o r c u r i n g agents (2) c u r e , v To change t h e p h y s i c a l p r o p e r t i e s of an a d h e s i v e , u s u a l l y by chemical r e a c t i o n , which may be c o n d e n s a t i o n , p o l y m e r i z a t i o n , v u l c a n i z a t i o n , o r c r o s s l i n k i n g Such change i s u s u a l l y accomplished by t h e a c t i o n of h e a t and c a t a l y s t , a l o n e o r i n combination, w i t h o r without , p r e s s u r e ( , modified) c u r e ( c u r i n g ) temperature The t e m p e r a t u r e t o which an a d h e s i v e o r an assembly i s s u b j e c t e d t o c u r e t h e a d h e s i v e ( ) c u r e ( c u r i n g ) time The p e r i o d of time n e c e s s a r y f o r an a d h e s i v e o r an assembly t o c u r e under s p e c i f i e d c o n d i t i o n s of t e m p e r a t u r e , o r p r e s s u r e , o r both ( ) c u r i n g a g e n t ( h a r d e n e r ) A s u b s t a n c e o r m i x t u r e of s u b s t a n c e s added t o an a d h e s i v e t o promote o r c o n t r o l t h e c u r i n g r e a c t i o n An a g e n t which does n o t e n t e r i n t o t h e r e a c t i o n i s known a s a c a t a l y t i c h a r d e n e r o r c a t a l y s t A r e a c t i v e c u r i n g a g e n t o r h a r d e n e r i s g e n e r a l l y used i n much g r e a t e r amounts t h a n a c a t a l y s t , and a c t u a l l y e n t e r s i n t o t h e r e a c t i o n (5) degrease To remove o i l and g r e a s e from adherend s u r f a c e s ( ) d e x t r i n e A water-based p r o d u c t d e r i v e d from t h e a c i d i f i c a t i o n and/or r o a s t i n g of s t a r c h (2) d i e l e c t r i c c u r i n g The u s e o f a high-frequency e l e c t r i c f i e l d through a j o i n t t o c u r e a s y n t h e t i c t h e r m o s e t t i n g adhesive A c u r i n g p r o c e s s f o r wood and o t h e r nonconductive j o i n t m a t e r i a l s d i l u e n t * A l i q u i d a d d i t i v e whose s o l e f u n c t i o n i s t o reduce t h e c o n c e n t r a t i o n o f s o l i d s and t h e v i s c o s i t y o f an a d h e s i v e composition d i l u e n t , r e a c t i v e A l o w - v i s c o s i t y l i q u i d added t o a h i g h - v i s c o s i t y s o l v e n t f r e e t h e r m o s e t t i n g a d h e s i v e which r e a c t s chemically w i t h t h e a d h e s i v e during c u r i n g The advantage of lowered v i s c o s i t y i s gained with minimum l o s s of other properties (3) d o c t o r r o l l A r o l l e r mechanism t h a t r e v o l v e s a t a d i f f e r e n t s u r f a c e speed, i n a d i r e c t i o n o p p o s i t e t o t h a t of t h e s p r e a d e r r o l l , r e s u l t i n g i n a wiping a c t i o n t o c o n t r o l t h e amount of a d h e s i v e s u p p l i e d t o t h e s p r e a d e r r o l l ( ) ( ) d r y , v To change t h e p h y s i c a l s t a t e of a n adhesive o r a n adherend by t h e l o s s of s o l v e n t c o n s t i t u e n t s by e v a p o r a t i o n , o r a b s o r p t i o n , o r both (1) e l a s t i c i t y , modulus o f deformed m a t e r i a l ( ) The r a t i o of s t r e s s t o s t r a i n i n e l a s t i c a l l y e l a s t o m e r A macromolecular m a t e r i a l which, a t room t e m p e r a t u r e , i s capable of r e c o v e r i n g s u b s t a n t i a l l y i n s i z e and shape a f t e r removal of deforming force (1) e x t e n d e r A s u b s t a n c e , g e n e r a l l y having some a d h e s i v e a c t i o n , added t o an a d h e s i v e t o reduce t h e amount of t h e primary b i n d e r r e q u i r e d p e r u n i t a r e a ( ) f a i l u r e , adherend J o i n t f a i l u r e by c o h e s i v e f a i l u r e of t h e adherend ( ) f a i l u r e , a d h e s i v e Rupture of an a d h e s i v e bond a t t h e i n t e r f a c e between t h e a d h e s i v e and adherend ( , m o d i f i e d ) f a i l u r e , c o h e s i v e Rupture of a n a d h e s i v e bond i n such a way t h a t t h e s e p a r a t i o n a p p e a r s t o be w i t h i n t h e adhesive (1, m o d i f i e d ) f a i l u r e , c o n t a c t The f a i l u r e of a n adhesive j o i n t a s a r e s u l t of incomplete c o n t a c t d u r i n g assembly, between adherend and a d h e s i v e s u r f a c e s o r between a d h e s i v e s u r f a c e s ( ) The s u r f a c e o f a n adherend which makes c o n t a c t with a n o t h e r adherend f e a t h e r i n g The t a p e r i n g of a n adherend on one s i d e t o form a wedge s e c t i o n , a s used i n a s c a r f j o i n t ( ) f i l l e r A r e l a t i v e l y nonadhesive s u b s t a n c e added t o a n a d h e s i v e t o improve t h e working p r o p e r t i e s , permanence, s t r e n g t h , o r o t h e r q u a l i t i e s (1) f i l l e t That p o r t i o n o f a n a d h e s i v e which f i l l s t h e c o r n e r o r a n g l e formed where two adherends a r e joined ( ) The t e r n f o r j u n c t i o n of t h e o u t e r s k i n and i n n e r c o r e i n honeycomb a s s e m b l i e s ( ) g l u e , n O r i g i n a l l y a hard g e l a t i n o b t a i n e d from h i d e s , tendons, c a r t i l a g e , bones, e t c o f animals Also, a n a d h e s i v e prepared from t h i s s u b s t a n c e by h e a t i n g with water Through g e n e r a l u s e t h e term i s now synonymous with t h e term "adhesive." ( ) The term i s most commonly used f o r wood a d h e s i v e s , however g l u e l i n e (bond l i n e ) The l a y e r o f adhesive which a t t a c h e s two adherends (1) The i n t e r f a c e between a n a d h e s i v e and a n adherend (3) g r e e n s t r e n g t h The a b i l i t y of an a d h e s i v e t o hold two s u r f a c e s t o g e t h e r when brought i n t o c o n t a c t and b e f o r e t h e a d h e s i v e d e v e l o p s i t s u l t i m a t e bond p r o p e r t i e s when f u l l y c u r e d (6) gum Any of a c l a s s of c o l l o i d a l s u b s t a n c e s exuded by, o r prepared from p l a n t s S t i c e when m o i s t , composed of complex c a r b o h y d r a t e s and organic a c i d s which a r e s o l u b l e o r s w e l l i n water ( ) hardener A s u b s t a n c e o r m i x t u r e of s u b s t a n c e s added t o a n adhesive t o promote o r c o n t r o l t h e c u r i n g r e a c t i o n by t a k i n g p a r t i n i t by c a t a l y s i s o r crosslinking ' h e a t r e a c t i v a t i o n The u s e of h e a t t o e f f e c t a d h e s i v e a c t i v i t y , e.g., hot-melt a d h e s i v e ; completion o f t h e c u r i n g p r o c e s s of a 3-staged r e s i n ( ) honeycomb c o r e A s h e e t m a t e r i a l , which may be m e t a l , foamed i n t o c e l l s ( u s u a l l y hexagonal) and used f o r sandwich c o n s t r u c t i o n i n s t r u c t u r a l a s s e m b l i e s , e s p e c i a l l y i n a i r c r a f t c o n s t r u c t i o n ( , modified) i n h i b i t o r A s u b s t a n c e t h a t slows down chemical r e a c t i o n I n h i b i t o r s a r e sometimes used i n c e r t a i n a d h e s i v e s t o prolong s t o r a g e o r working l i f e ( ) interface The c o n t a c t a r e a between adherend and a d h e s i v e s u r f a c e s ( ) Jig* A former used t o h o l d a bonded assembly u n t i l t h e a d h e s i v e has cured joint The l o c a t i o n a t which two adherends a r e h e l d t o g e t h e r with a l a y e r of a d h e s i v e ( ) j o i n t , b u t t A j o i n t made by bonding two s u r f a c e s t h a t a r e p e r p e n d i c u l a r t o t h e main s u r f a c e of t h e adherends ( ) j o i n t , la^ A j o i n t made by p l a c i n g one adherend p a r t l y o v e r a n o t h e r and bonding t o g e t h e r t h e p o r t i o n s of t h e adherends Double-lap j o i n t s involve t h e o v e r l a p p i n g by opposing f a c e s of one adherend ( ) j o i n t , s c a r f - , A j o i n t made by c u t t i n g away s i m i l a r segments of two a d h e r e n d s a t an a n g l e l e s s than 45 d e g r e e s t o t h e major a x i s o f two adherends and bonding t h e adherends with t h e c u t a r e a s f i t t e d t o g e t h e r t o be coplanar ( ) (3) j o i n t , s t a r v e d A j o i n t t h a t h a s a n i n s u f f i c i e n t amount o f a d h e s i v e t o produce a s a t i s f a c t o r y bond T h i s c o n d i t i o n may r e s u l t from t o o t h i n a spread t o f i l l t h e g a p between t h e adherends, e x c e s s i v e p e n e t r a t i o n of t h e adhesive i n t o t h e adherend (when porous), t o o s h o r t a n assembly time, o r t h e use of e x c e s s i v e p r e s s u r e ( , modified) l a m i n a t e , n o A product made by bonding t o g e t h e r two o r more l a y e r s of material o r materials (1) l a m i n a t e , v To u n i t e l a y e r s of m a t e r i a l w i t h adhesive ( ) l a m i n a t e , c r o s s , n A l a m i n a t e i n which some of t h e l a y e r s of m a t e r i a l a r e o r i e n t e d a t r i g h t a n g l e s t o t h e remaining l a y e r s w i t h r e s p e c t t o t h e g r a i n o r s t r o n g e s t d i r e c t i o n i n tension (1, modified) l a m i n a t e , p a r a l l e l , n A l a m i n a t e i n which t h e g r a i n of a l l l a y e r s of m a t e r i a l a r e o r i e n t e d approximately p a r a l l e l t o each o t h e r ( ) l e g g i n g The drawing of f i l a m e n t s o r s t r i n g s when a d h e s i v e bonded s u b s t r a t e s a r e separated (1) m a t r i x The p a r t of a n adhesive which s u r r o u n d s o r e n g u l f s embedded f i l l e r o r r e i n f o r c i z g p a r t i c l e s and f i l a m e n t s ( ) modifier Any c h e m i c a l l y i n e r t i n g r e d i e n t added t o an adhesive formulation t h a t changes i t s p r o p e r t i e s ( ) moduluso S e e e l a s t i c i t y , madulus o f monomer A r e l a t i v e l y simple compound which can r e a c t t o form a polymer (1) mucilage An a d h e s i v e prepared from a gum and water Also, i n a more g e n e r a l s e n s e , a l i q u i d adhesive which h a s a low o r d e r of bonding s t r e n g t h ( ) Newtonian f l u i d A f l u i d i n which t h e s h e a r i n g r a t e is d i r e c t l y p r o p o r t i o n a l t o t h e applied torque (2) novalak A phenolic-aldehydic r e s i n t h a t , u n l e s s a s o u r c e of methyleae g r o u p s i s added, remains permanently t h e r m o p l a s t i c ( ) open time See open assembly t i m e under time, assembly, p a s t e , n An a d h e s i v e composition h a v i n g a c h a r a c t e r i s t i c p l a s t i c - t y p e c o n s i s t e n c y , t h a t i s , a h i g h o r d e r o f y i e l d v a l u e , such as t h a t of an a d h e s i v e p r e p a r e d by h e a t i n g m i x t u r e of s t a r c h and w a t e r and s u b s e q u e n t l y c o o l i n g t h e hydrolyzed product (1, m o d i f i e d ) penetration ermanence The passage of a n a d h e s i v e i n t o a n adherend (2) The r e s i s t a n c e of a n a d h e s i v e bond t o d e t e r i o r a t i n g i n f l u e n c e s (-1 p l a s t i c i t y A p r o p e r t y of a d h e s i v e s t h a t a l l o w s t h e m a t e r i a l t o be deformed c o n t i n u o u s l y and permanently w i t h o u t r u p t u r e upon t h e a p p l i c a t i o n of a f o r c e t h a t exceeds t h e y i e l d v a l u e of t h e m a t e r i a l ( ) p l a s t i c i z e r A m a t e r i a l , such as a h i g h - b o i l i n g - p o i n t o r g a n i c s o l v e n t , incorporated i n a n adhesive t o i n c r e a s e i t s f l e x i b i l i t y , workability, o r d i s t e n s i b i l i t y (1) polymer A compound formed by t h e r e a c t i o n of simple molecules having f u n c t i o n a l groups which permit t h e i r combination t o proceed t o h i g h e r m o l e c u l a r weights under s u i t a b l e c o n d i t i o n s ( ) p o l y m e r i z a t i o n A chemical r e a c t i o n i n which t h e molecules o f a monomer a r e l i n k e d t o g e t h e r t o form l a r g e m o l e c u l e s whose m o l e c u l a r weight is a m u l t i p l e of t h a t i n t h e o r i g i n a l s u b s t a n c e When two o r more monomers a r e i n v o l v e d , the process i s c a l l e d copolymerization o r heteropolymerization (1) porosity The a b i l i t y of an adherend t o a b s o r b an adhesive ( ) p o s t c u r e , v To expose an a d h e s i v e assembly t o a n a d d i t i o n a l c u r e , f o l l o w i n g t h e i n i t i a l c u r e , f o r t h e purpose of modifying s p e c i f i c p r o p e r t i e s (1) p o s t - v u l c a n i z a t i o n bonding Conventional a d h e s i v e bonding of p r e v i o u s l y v u l c a n i z e d e l a s t o m e r i c adherends p o t l i f e (working l i f e ) The p e r i o d of time d u r i n g which a n adhesive o r r e s i n p r e p a r e d f o r a p p l i c a t i o n a f t e r mixing w i t h c a t a l y s t , s o l v e n t , o r o t h e r compounding i n g r e d i e n t s , remains u s a b l e ( ) ( ) prebond t r e a t m e n t See s u r f a c e p r e p a r a t i o n p r e s s u r e - s e n s i t i v e a d h e s i v e s (PSA'S) Adhesive m a t e r i a l s which bond t o adherend s u r f a c e s a t room t e m p e r a t u r e immediately a s low p r e s s u r e i s a p p l i e d (3) p r i m e r A c o a t i n g a p p l i e d t o a s u r f a c e of a n adherend p r i o r t o t h e a p p l i c a t i o n o f a n adhesive t o improve a d h e s i o n and/or d u r a b i l i t y of t h e bond (3) release agent resite resitol resol An adhesive material which prevents bond formation ( ) An alternative term for C-stage (q.v.) (1) An alternative term for 8-stage (q.v.1 An alternative term for A-stage (q.v.1 (1) (1) sagging Run or flow-off of adhesive from an adherend surface due to application of excess or low viscosity material ( ) sandwich panel An assembly composed of metal skins (facings) bonded to both sides of a lightweight core (2) sealant A gap-filling material to prevent excessive absorption of adhesive, or penetration of liquid or gaseous substances (2) self-vulcanizing, adi Pertaining to an adhesive that undergoes vulcanization without the application of heat (1) service conditions The environmental conditions to which a bonded structure is exposed, e.g., heat, cold, humidity, radiation, vibration, etc (2) set, v To convert an adhesive into a fixed or hardened state by chemical or physical action, such as condensation, polymerization, oxidation, vulcanization, gelation, hydration, or evaporation of volatile constituents (1) The term is usually used for thermoplastic adhesives, unless a chemical process, such as polymerization, is involved ( ) shear, tensile The apparent stress applied to an adhesive in a lap joint (2) shelf life See storage life shrinkage The volume reduction occurring during adhesive curing, sometimes expressed as a percentage volume or linear shrinkage: size reduction of adhesive layer due to solvent loss or catalytic reaction ( ) , slippage The movement of adherends with respect to each other during the bonding process (1) solids content adhesive (1) solvent bonding The percentage by weight of the nonvolatile matter in an See solvent welding solvent cement An.adhesive utilizing an organic solvent as the means of depositing the adhesive constituent ( ) solvent cementinq See solvent welding s o l v e n t r e a c t i v a t i o n The a p p l i c a t i o n o f s o l v e n t t o a d r y a d h e s i v e l a y e r t o regenerate its wetting p r o p e r t i e s (2) s o l v e n t welding ( s o l v e n t bonding) ( s o l v e n t cementing) The p r o c e s s of j o i n i n g a r t i c l e s made of t h e r m o p l a s t i c r e s i n s by a p p l y i n g a s o l v e n t capable of s o f t e n i n g t h e s u r f a c e s t o be j o i n e d , and p r e s s i n g t h e s o f t e n e d s u r f a c e s t o g e t h e r Adhesion i s a t t a i n e d by means o f e v a p o r a t i o n of t h e s o l v e n t , a b s o r p t i o n o f t h e s o l v e n t i n t o a d j a c e n t m a t e r i a l and/or p o l y m e r i z a t i o n of t h e s o l v e n t cement ( ) squeeze-out Excess a d h e s i v e p r e s s e d o u t a t t h e bond l i n e due t o p r e s s u r e a p p l i e d i n t h e adherends ( , m o d i f i e d ) s t a b i l i z e r An a d h e s i v e a d d i t i v e which p r e v e n t s o r minimizes change i n p r o p e r t i e s , e.g., by adherend a b s o r p t i o n , d e m u l s i f i c a t i o n , o r r a p i d chemical reaction s t o r a g e l i f e The p e r i o d of time d u r i n g which a packaged a d h e s i v e can be s t o r e d under s p e c i f i e d t e m p e r a t u r e c o n d i t i o n s and remain s u i t a b l e f o r use Sometimes c a l l s h e l f l i f e ( ) R e f r i g e r a t e d s t o r a g e o f t e n e x t e n d s s t o r a g e l i f e considerably s t r e n g t h , cleavage The t e n s i l e l o a d expressed i n f o r c e p e r u n i t of width of bond r e q u i r e d t o cause c l e a v a g e s e p a r a t i o n of a t e s t specimen of u n i t length (2) s t r e n g t h , f a t i g u e The maximum l o a d t h a t a j o i n t w i l l s u s t a i n when subjected t o repeated s t r e s s a p p l i c a t i o n a f t e r drying, o r a f t e r a conditioning p e r i o d under s p e c i f i e d c o n d i t i o n s ( ) s t r e n g t h , impact A b i l i t y o f a n a d h e s i v e m a t e r i a l t o r e s i s t shock by a sudden p h y s i c a l blow d i r e c t e d a g a i n s t i t Impact shock i s t h e t r a n s m i s s i o n of s t r e s s t o an a d h e s i v e i n t e r f a c e by sudden v i b r a t i o n o r j a r r i n g blow of t h e assembly, measured i n work u n i t s p e r u n i t a r e a ( ) s t r e n g t h , l o n g i t u d i n a l - s h e a r ( l a p - j o i n t s t r e n g t h ) The f o r c e n e c e s s a r y t o r u p t u r e a n a d h e s i v e j o i n t by means o f s t r e s s a p p l i e d p a r a l l e l t o t h e plane o f ' t h e bond (3) s t r e n g t h , p e e l The f o r c e p e r u n i t w i d t h n e c e s s a r y t o b r i n g a n a d h e s i v e t o t h e p o i n t of f a i l u r e and/or t o m a i n t a i n a s p e c i f i e d r a t e of f a i l u r e by means of a s t r e s s a p p l i e d i n a p e e l i n g mode ( ) , s t r e n g t h , s h e a r The r e s i s t a n c e o f a n a d h e s i v e j o i n t t o s h e a r i n g s t r e s s e s ; the force per u n i t area sheared, a t f a i l u r e (2) s t r e n g t h , t e n s i l e The r e s i s t a n c e of a n adhesive j o i n t t o t e n s i l e s t r e s s ; t h e f o r c e p e r u n i t a r e a under t e n s i o n a t f a i l u r e ( ) s t r u c t u r a l adhesive See a d h e s i v e , s t r u c t u r a l and s t r u c t u r a l bond s t r u c t u r a l bond A bond which s t r e s s e s t h e adherend t o t h e y i e l d p o i n t , t h e r e b y t a k i n g f u l l advantage o f t h e s t r e n g t h of t h e adherend On the b a s i s of t h i s d e f i n i t i o n , a d e x t r i n a d h e s i v e used with p a p e r (e.g., p o s t a g e stamps, e n v e l o p e s , e t c ) and which c a u s e s f a i l u r e of t h e paper, forms a s t r u c t u r a l bond The s t r o n g e r t h e adherend, t h e g r e a t e r t h e demands p l a c e d on t h e a d h e s i v e Thus, few a d h e s i v e s q u a l i f y a s " s t r u c t u r a l " f o r m e t a l s A f u r t h e r requirement f o r a s t r u c t u r a l a d h e s i v e i s t h a t i t be a b l e t o s t r e s s t h e adherend t o i t s y i e l d p o i n t a f t e r exposure t o i t s i n t e n d e d environment (8) s u b s t r a t e A m a t e r i a l upon t h e s u r f a c e of which a n a d h e s i v e - c o n t a i n i n g s u b s t a n c e i s spread f o r any p u r p o s e , such a s bonding o r c o a t i n g A broader term t h a n adherend, q.v ( ) s u r f a c e p r e p a r a t i o n ( s u r f a c e t r e a t m e n t ) A p h y s i c a l , o r chemical p r e p a r a t i o n , o r b o t h , o f a n adherend t o r e n d e r i t s u i t a b l e f o r adhesive j o i n i n g ( ) The term prebond t r e a t m e n t i s sometimes used, b u t i s deprecated (2) t a c k The p r o p e r t y of a n a d h e s i v e t h a t e n a b l e s i t t o form a bond of measurable s t r e n g t h immediately a f t e r a d h e s i v e and adherend a r e brought i n t o c o n t a c t under low p r e s s u r e ( ) t a c k , aggressive See t a c k , dry t a c k d r y , n The p r o p e r t y of c e r t a i n a d h e s i v e s , p a r t i c u l a r l y nonvulcanizing r u b b e r a d h e s i v e s , t o a d h e r e on c o n t a c t t o themselves a t some s t a g e i n t h e e v a p o r a t i o n of v o l a t i l e c o n s t i t u e n t s , even though t h e y seem d r y t o t h e touch Sometimes c a l l e d a g g r e s s i v e t a c k ( ) ( ) t a c k - d r y ( t a c k y - d r y ) , a d j The s t a t e of an a d h e s i v e which h a s l o s t s u f f i c i e n t v o l a t i l e s (by e v a p o r a t i o n o r a b s o r p t i o n i n t o t h e adherend) t o l e a v e i t i n t h e r e q u i r e d s t i c k y ( t a c k y ) c o n d i t i o n (3) t a c k i f i e r An a d d i t i v e i n t e n d e d t o improve t h e s t i c k i n e s s of a c a s t a d h e s i v e f i l n ; u s u a l l y a c o n s t i t u e n t of rubber based and s y n t h e t i c - r e s i n adhesives ( ) t a c k range ( t a c k s t a g e ) The p e r i o d of time i n which an a d h e s i v e w i l l remain i n t h e tacky-dry c o n d i t i o n a f t e r a p p l i c a t i o n t o a n adherend under s p e c i f i e d c o n d i t i o n s o f t e m p e r a t u r e and humidity ( ) ( ) tape A film form o f a d h e s i v e which may be supported on c a r r i e r m a t e r i a l (2 f - - t e m p e r a t u r e , curing The t e m p e r a t u r e t o which an a d h e s i v e o r a n assembly i s s u b j e c t e d t o c u r e t h e a d h e s i v e The temperature a t t a i n e d by t h e adhesive i n t h e p r o c e s s o f c u r i n g i t ( a d h e s i v e c u r i n g temperature) may d i f f e r from t h e t e m p e r a t u r e of t h e atmosphere s u r r o u n d i n g t h e assembly (assembly c u r i n g temperature), (1) temperature, drying The temperature t o which an adhesive on a n adherend, o r i n an assembly, o r t h e assembly i t s e l f , i s subjected t o dry t h e adhesive The temperature a t t a i n e d by t h e adhesive i n t h e process of drying it (adhesive drying temperature) may d i f f e r from the temperature of t h e atmosphere surrounding t h e assembly (assembly drying temperature) (1) temperature, s e t t i n g The temperature t o which an adhesive assembly i s s u b j e c t e d t o s e t the adhesive The temperature a t t a i n e d by t h e adhesive i n t h e process of s e t t i n g i t (adhesive s e t t i n g temperature) may d i f f e r from t h e temperature of t h e atmosphere surrounding t h e assembly (assembly s e t t i n g temperature) ( ) t e s t s , d e s t r u c t i v e T e s t s involving the d e s t r u c t i o n of assemblies i n order t o 'evaluate t h e maximum performance of t h e adhesive bond ( ) t e s t s , nondestructive I n s p e c t i o n t e s t s f o r t h e e v a l u a t i o n of bond q u a l i t y without damaging the assembly, e.g., u l t r a s o n i c s , v i s u a l i n s p c t i o n , e t c ( ) t h e r m o p l a s t i c , adj Capable of being repeatedly softened by heat and hardened by cooling ( ) thermoset ( t h e r m o s e t t i n g ) , ad j Having t h e property of undergoing a chemical r e a c t i o n by t h e a c t i o n of h e a t , c a t a l y s i s , u l t r a v i o l e t l i g h t , e t c l e a d i n g t o a r e l a t i v e l y i n f u s i b l e s t a t e (1, modified) t h i n q l e r , n A v o l a t i l e l i q u i d added t o an adhesive t o modify t h e consistkncy o r o t h e r p r o p e r t i e s ( ) ( a l s o c a l l e d d i l u e n t ) t h i x o t r o p i c , adj t h i x o t r o p y (q.v ) A term a p p l i e d t o m a t e r i a l s having t h e property of thixotropy A property of m a t e r i a l s which d i s p l a y a reduction i n v i s c o s i t y when a shearing a c t i o n i s applied Some adhesive systems become t h i n n e r i n consistency on a g i t a t i o n and t h i c k e r again when l e f t undisturbed (2) time, assembly, The time i n t e r v a l between t h e spreading of t h e adhesive on t h e ad.herend and the a p p l i c a t i o n of pressure o r h e a t , o r both, t o t h e assembly For assemblies involving m u l t i p l e l a y e r s o r p a r t s , t h e assembly time begins with the spreading of t h e adhesive on t h e f i r s t adherend Assembly time i s t h e sum of the open and closed assembly times Open assembly time i s the time i n t e r v a l between t h e spreading of the adhesive on the adherend and the completion of t h e assembly of t h e p a r t s f o r bonding During t h i s period t h e adhesive-coated s u r f a c e s a r e exposed t o t h e a i r before being brought i n t o contact Closed assembly time is t h e time i n t e r v a l between completion of assembly of the p a r t s f o r bonding and t h e a p p l i c a t i o n of p r e s s u r e o r h e a t , o r both, t o c u r e o r s e t t h e adhesive ( , modified) (3) time, curing The period of time during which an assembly i s subjected t o h e a t o r pressure, o r both, t o cure t h e adhesive F u r t h e r cure may take place a f t e r removal of t h e assembly from t h e c o n d i t i o n s of h e a t , o r pressure, o r both (1) t i m e , d r y i n g The p e r i o d of time d u r i n g which an a d h e s i v e on an adherend o r a n assembly i s allowed t o dry w i t h o r w i t h o u t t h e a p p l i c a t i o n of h e a t , o r p r e s s u r e , o r both ( ) time, joint-conditioning The time i n t e r v a l between t h e removal of the j o i n t from t h e c o n d i t i o n s of h e a t , o r p r e s s u r e , o r both, used t o accomplish bonding and t h e a t t a i n m e n t o f a p p r o x i m a t e l y maximum bond s t r e n g t h Sometimes c a l l e d j o i n t a g i n g time ( ) t i m e , s e t t i n g The p e r i o d of time d u r i n g which an assembly i s s u b j e c t e d t o h e a t , o r p r e s s u r e , o r b o t h , t o s e t t h e adhesive ( ) v e h i c l e The c a r r i e r medium ( l i q u i d ) f o r a n a d h e s i v e m a t e r i a l which improves i t s e a s e of a p p l i c a t i o n t o adherends; s o l v e n t component of an adhesive (2) v i s c o s i t y A measure of t h e r e s i s t a n c e t o flow of a l i q u i d For Newtonian l i q u i d s , t h e s h e a r r a t e is p r o p o r t i o n a l t o t h e s h e a r s t r e s s between laminae of moving f l u i d ; f o r non-Newtonian l i q u i d s i t i s n o t p r o p o r t i o n a l ( ) v u l c a n i z a t i o n A chemical r e a c t i o n i n which t h e p h y s i c a l p r o p e r t i e s of a r u b b e r a r e changed i n t h e d i r e c t i o n of d e c r e a s e d p l a s t i c flow, l e s s s u r f a c e t a c k i n e s s , and i n c r e a s e d t e n s i l e s t r e n g t h by r e a c t i n g i t w i t h s u l f u r o r o t h e r s u i t a b l e agents (1) weldbonding A p r o c e s s i n which a j o i n t i s formed by s p o t welding through a n uncured a d h e s i v e bond l i n e , o r by f l o w i n g an a d h e s i v e i n t o a spot-welded joint (4) w e t t i n g A s u r f a c e i s s a i d t o be c o m p l e t e l y wet by a l i q u i d i f t h e c o n t a c t a n g l e i s z e r o , and i n c o m p l e t e l y wet i f i t i s a f i n i t e angle S u r f a c e s a r e commonly regarded a s u n w e t t a b l e i f t h e a n g l e exceeds 90 degrees ( ) working l i f e See p o t l i f e REFERENCES American Society for Testing and Materials (ASTM), ASTM D907-82, "Standard Definitions of Terms Relating to ~dhesives', 1982, publish4 in volume 15.06 (~dhesives), Annual Book of ASTM Standards Shields, J., ADHESIVES HANDBOOK, 2nd Edition, Newnes-Butterworth, London, 1976 (available from Butterworths, Woburn, HA 01801) International Organization for Standardization (ISO), International Standard (IS) 6354, "Adhesives - Vocabulary", First Edition, 1982 Available from American National Standards Institute (ANSI), 1430 Broadway, MIC, NY 10018 Rodgson, W E., Chapter 13, "Pressure Sensitive Adhesives and Their Applications", ADHESION 3, (K.w Allen, Ed ) , Applied Science Publishers, Ltd Available from the International Ideas, Inc., Philadelphia, PA Whittington, LOR., WHITTINGTON's DICTIONARY OF PLASTICS, 2nd Edition, Technomic Publishing Co., Wes tport, CT, 1978 (sponsored by the Society of Plastics ~ngineers) Synthetic Surfaces, Inc., Scotch Plains, NJ, "The 1mportanc.e of Green Strength in Adhesive Selection", Tech Sheet 472A, 1982 Rayner, C.A.A., Chapter 4, "Synthetic Organic Adhesives", ADHESION AND ADHESIVES, 2nd Edition, gVol - Adhesives, (R Houwink and G Salomon, eds ) , Elsevier Publishing Co , 1965 DeLollis, NJ, ADHESIVES, ADHERENDS, ADHESION, Robert E Krieger Publishing Co., Huntington, NY, 1980 Bolger, J.C., "Single-Component Epoxy Adhesives for Sheet Steel and Aluminum Bonding", pp 369-387 in APPLIED POLYMER SYMPOSIA No 32, Durability of Adhesive Bonded Structures, 1977, (M J Bodnar, Ed ) Paper presented at Symposium at Picatinny Arsenal, Dover, NJ, Oct 27-29, 1976 NOTES Subject term (key word) listing Adherends Adhesives Adhesive Bonding Durability Handbook Joint Design Specifications Surface Preparation Test Methods Preparing activity: Custodians: - Army Army MR Navy AS Air Force 99 Army ME, GL, MI Navy AS, SH Air Force 20 User activities: - AT, 2ik YD (WP# ID-741lA/DISC-0038~, MR Project No 8040-0347 Review activities: Army Navy FOR MTL USE ONLY) ... i e l e c t r i c bonding (high frequency bonding) Induction heating (electromagnetic bonding) Ultraaonic welding Ultrasonic adhesive bonding Spin o r f r i c t i o n welding Adhesives f o r elastomers... Paragraph IWTRODUCTION TO A D M l V Y , BONDING I Definition of adhesive bonding Functions of adhesives Advantages and disadvantwes of adhesive bonds Ad ventages Disadvantages... time) S e t t i n g time E a r l i e s t handling time Adhesives f o r metals Adhesives f o r p l a s t i c s Solvent cementing Adhesive bonding Thennal w e l d i n g techniques Direct heetiag