国外专利EVA--Titre du document

Titre du document / Document titleFactors that affect the EVA encapsulant discoloration rate upon accelerated exposureAuteur(s) / Author(s) PERN F. J. (1) ;Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)(1) Measurements and Characterization Branch, Photovoltaics Division, National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401,ETATS-UNISRésumé / Abstract Copyright (c) 1996 Elsevier Science B.V. All rights reserved. Several factors that affect the discoloration rate of the ethylene-vinyl acetate (EVA) copolymer encapsulants used in crystalline-Si photovoltaic (PV) modules upon accelerated exposure have been investigated primarily by employing UV-visible spectrophotometry, spectrocolorimetry, and fluorescence analysis. A variety of film samples including the two typical (unprimed) EVA formulations, A9918 and 15295, were studied. The films were laminated, cured, and exposed to either a concentrated 1-kW Xe or an enhanced-UV light source. The results indicate that the extent of EVA discoloration can be affected by factors of two general categories:chemical and physical. Inthe chemical category, thedegradative factors include(1) EVA formulation, (2)presence and concentrationof curing-generated,UV-excitable chromophoresthat depend on the type ofcuring agent used, (3) lossrate of the UV absorber,Cyasorb UV 531TM, (4)curing agent and curingconditions, and (5)photobleaching reactionsdue to diffusion of air intothe laminated films. In thephysical category, thefactors involve (6) UV lightintensity, (7) UV-filteringeffect of glass superstrates,(8) gas permeability ofpolymeric superstrates, (9)film thickness, and (10)lamination−delamination(maybe chemical and/ormechanical effect, too).Photodecomposition of theCyasorb was first verified incyclohexane solutions andthen in Elvax 150TM (EVX)films (the copolymer withoutany additives and curingagent). Cyasorbdecomposition rates incyclohexane solutions areexponentially proportionalto the light intensity, but canbe greatly reduced by afree-radical scavenger,Tinuvin 770TM, andfurthermore by anantioxidant, Naugard P TM.The discoloration rate ofEVA increases withincreasing loss of CyasorbUV 531 and is faster for theEVA A9918 films that havea greater concentration ofUV-excitable chromophoresgenerated from a slowercuring than for the EVA15295 films that are fastcured. In general, the lossrate of the UV absorber andthe rate of discolorationfrom light yellow to brownfollow a sigmoidal pattern. Areasonably good correlationfor changes intransmittance at 420 nm,yellowness index, andfluorescence peak area (orintensity ratio) is obtainedas the extent of EVAdiscoloration progresses.No discoloration wasobserved for the laminatedEVX films that contain nostabilizers andcuring-generatedchromophores. Thediscoloration rate of bothtypes of EVA can be largelyreduced by UV-filteringglass superstrates thatremove UV<320 nm.Photobleaching reactionsare responsible for thenon-discoloration ofunlaminated EVA, thevisually clear perimeteraround the edges oflaminated samples, and theEVA films laminated withgas-permeable polymer filmsuperstrates. Delaminationof EVA films from the topglass superstrate wasobserved after prolongedUV exposure.Revue / Journal TitleSolar energy materials andsolarcells ISSN 0927-0248Source / Source1996, vol. 41-42, pp. 587-615Langue / LanguageAnglaisEditeur / PublisherElsevier, Amsterdam,PAYS-BAS (1992) (Revue)Mots-clés anglais /English KeywordsPhotovoltaic array ;Photovoltaic conversion ;Silicon ; Discoloration ;Irradiance ; Experimentalstudy ; Reactionmechanism ; Stabilization ;INIST-CNRS, Cote INIST :18016, 35400006008917.0098Copyright 2007INIST-CNRS. All rightsreservedToute reproduction oudiffusion même partielle,par quelque procédé ou surtout support que ce soit, nepourra être faite sansl'accord préalable écrit del'INIST-CNRS.No part of these recordsmay be reproduced ofdistributed, in any form orby any means, without theprior written permission ofINIST-CNRS.Nº notice refdoc (ud4) :3119483/pat ents/5447576/description.htmlDescriptionFIELD OF THE INVENTIONThis invention pertains to encapsulants for solar cells. More particularly, this invention pertains to a composition of an EVA encapsulant which minimizes thermal discoloration.BACKGROUND OF THE INVENTIONEncapsulants used to protect solar cells from the environment must possessseveral characteristics. First, the encapsulant must be easily deformable, prior to being cured, so it can conform to the shape of the solar cell forproper sealing without breaking the relatively fragile solar cell. Also, the cured formulation of the encapsulant must be a thermoset compound,i.e. a compound which is resistant to flow when exposed to heat. Because a solar cell is exposed to heat during its normal operation, a compound which readily flows when exposed to heat, i.e. a thermoplastic compound, would not be suitable for use as an encapsulant. Athermoplastic compoundwould likely flow off ofthe solar cell, therebycausing the solar cell tobecome exposed during itsnormal operation.Additionally, theencapsulantmust be adhesive to adhereto the cell and othercomponents duringoperation. Finally, theencapsulant must beoptically transparent.Ethylene-vinyl acetate(EVA) co-polymers areamong the most widely usedencapsulants for themanufacture of solar cells,or solar modules.However, field experienceshows that a gradualdiscoloration developswithin the encapsulant.This discoloration lowersthe power output of themodule by approximately 5%.This discoloration effecthas been primarilynoticed in hotenvironments; however,EVA encapsulants in otherenvironments also tend toeventually showdiscoloration. Thisdiscoloration may becaused by exposure to heat,i.e. thermaldiscoloration, and/or byexposure to light, such asultraviolet light. Thediscoloration appears as ayellowing of the EVAencapsulant, which is anabsorption in the blue endof the spectrum, anddecreases the powerconversion in this range.In the past, someadditives have been usedto attempt to minimizeencapsulant discoloration.One such additive is thecompoundBis-(Tetramethylpiperidinyl sebacate),produced by Ciba-GeigyCorporationof Hawthorne, N.Y. andsold under the trademark"TINUVIN 770". However, aneed still exists tofurther minimize thermaldiscoloration.SUMMARY OF THE INVENTIONThe present invention isdirected to a compositionfor encapsulating asolar cell and minimizingthermal discoloration ofthe encapsulant. Thecomposition includes anethylene-vinyl acetate(EVA) copolymer, a curingagent and one of twoparticularly well-suitedhindred amine lightstabilizers, either0,0-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl)mono-peroxycarbonate orPoly[(4-hydroxy-2,2,6,6-tetramethyl-l-piperidine-ethanol) -co-dimethylsuccinate]. The curingagent may be either2,5-Dimethyl-2,5-Di-t-Butylperoxyhexane; orO,O-t-Butyl-O-(2-ethylhexyl)mono-peroxycarbonate orany other conventionalcuring agent.In an alternativeembodiment of the presentinvention, thecompositionincludes only an EVAcopolymer andO,O-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl) mono-peroxycarbonate,which serves the functionsof both the curing agentand the hindered aminelight stabilizer.In one embodiment of thepresent invention, aprimer may be added to theformulation to serve toenhance adherence of theencapsulant to the solarcell.In another alternativeembodiment of the presentinvention, the selectedhindered amine lightstabilizer is added in anamount in the range of 0.1to 0.5 parts per hundredparts by weight ofethylene-vinyl acetatecopolymer and the curingagent is added in an amountequivalent to 1.5parts per hundred partsethylene-vinyl acetatecopolymer.The present inventionincludes a method ofproducing an encapsulant for asolar cell. This method includes mixing one of the two above-mentioned hindered amine light stabilizers with an ethylene-vinyl acetate copolymer,a curing agent and, optionally, a primer. Then, the method includes applying the mixture to the solar cell and curing the applied mixture to form a thermoset encapsulant for the solar cell. Alternatively, if theselected hindered amine light stabilizer isO,O-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl) mono-peroxycarbonate, the curing agent need not be included.The present invention also includes the product produced by the above method. This product is a cured, transparent encapsulant for a solar celland includes across-linkedethylene-vinyl acetate copolymer and ahindered amine light stabilizer selected from the group consisting of O,O-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl)mono-peroxycarbonateorPoly[(4-hydroxy-2,2,6,6-tetramethyl-1-piperidine-ethanol) -co-dimethylsuccinate].BRIEF DESCRIPTION OF THEDRAWINGSFIGS. 1 through 6 plot thetime it takes for theoptical transmission todegrade to a particularvalue at a specifiedwavelength.DESCRIPTION OF THEINVENTIONThis invention is directedto a composition forminimizing thediscoloration in anencapsulant for a solarcell. The compositionincludesan ethylene-vinyl acetate(EVA) copolymer, a curingagent and a hinderedamine light stabilizerselected from the groupconsisting ofO,O-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl)mono-peroxycarbonate orPoly[(4-hydroxy-2,2,6,6-tetramethyl-1-piperidine-ethanol) -co-dimethylsuccinate]. Alternatively,if the selected hinderedamine light stabilizeris0,0-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl)mono-peroxycarbonate, thecuring agent need not beincluded. Thiscomposition is cured andthe subsequently formedproduct shows improvedresistance to thermaldiscoloration.Ethylene-vinyl acetatecopolymer, commonly knownin the art as EVA, refersto a whole class ofpolymers (or "resins")which are generally usedtoimprove adhesionproperties of hot-melt andpressure sensitiveadhesives.One particular use of EVAis as an encapsulant for asolar cell.In the present invention,the EVA copolymer used maybe any EVA copolymerknown in the art for thisparticular use.Preferably, the EVAcopolymerhas a vinyl acetatecontent between 25% and35%. One such EVAcopolymerwhich can be used in thepresent invention is soldunder the trademark"ELVAX-150" by DuPont ofWilmington, Del.A formulated version ofthe "ELVAX-150" EVA is"EVA A-9918", whichcontainsthe required curing agentsand stabilizers necessaryfor solar modulefabrication. Inparticular, the EVA-9918formulation which isproduced bySpringborn Laboratoriesof Enfield, Conn. consistsof the followingmixture:______________________________________"phr"______________________________________ELVAX-150 EVA (DuPont)100.0LUPERSOL-101 Peroxide(Atochem)1.5CYASORB UV-531 (Am.Cyanamide)0.3NAUGARD-P (Uniroyal) 0.2TINUVIN-770 (Ciba-Geigy)0.1______________________________________Other suitableformulations are made byRichmond Industries ofRedland Ca.;Bridgestone Tire & Rubberof Tokyo, Japan; andEtimex Gmbh of Germany. Anadditional modificationof this compound,designated A-9918-Pincludes theprimer "Z-6030" at a levelof 0.25 phr. SpringbornLaboratories alsoproduces "EVA 15295" alsoknown as the "fast cure" version, in which the LUPERSOL-101 peroxide curing agent is replaced by LUPERSOL-TBEC.The curing agent used in the present invention may be any curing agentknown in the art. A purpose of the curing agent is to serve tosufficiently cross-link the EVA during the cure cycle. The cured encapsulant should be a thermoset compound so that the integrity of thesolar cell is not breached when exposed to heat. Two curing agents whichhave been used with successful results are2,5-Dimethyl-2,5-Di-t-Bu tylperoxyhexane, which is sold under the trademark "LUPERSOL 101", andO,O-t-Butyl-O-(2-ethylhe xyl) mono-peroxycarbonate, which is sold under the trademark "LUPERSOL TBEC" by Atochem of Buffalo, N.Y.The amount of curing agent used may vary widely depending on theparticularapplication. In experiments disclosed in the examples below, the amount ofcuring agent added was 1.5 parts per hundred parts of the EVA resin"ELVAX-150". The designation "phr" will be used hereinafter toindicateparts per hundred parts ofthe EVA copolymer.One embodiment of theinvention is directed to acomposition forminimizingthermal discoloration inan EVA encapsulant. Thiscomposition includes anEVA copolymer, a curingagent and a discolorationstabilizer (one of thetwo particularlywell-suited hinderedamine light stabilizersdiscussed inmore detail below).According to anotherembodiment of theinvention, a primer isalso added toserve to enhance adherenceof the encapsulant to thesolar cell. Theprimer used in the presentinvention may be anyprimer known in the art.Primers well known in thestate-of-the-art includecompounds in the broadclass of chemistry knownas "organo-silanes".Chemically, this group ofprimers may be representedby the formula (R--O)3--Si--(C3H6)--R'. Primers useful inEVA encapsulant formulashave twochemically functionalparts, R and R'. The first("R") is the part thatreacts with glass, solarcells and other inorganicsurfaces. "R" may bemethyl (CH3--), ethyl (CH3CH2 --), or acetyl (CH3--CO--) The otherfunctional part, R',reacts with the EVApolymer duringthe cure and may be any ofthe following chemicalgroups: methacrylate,acrylate, vinyl, maleate,itaconate, cinnamate orany other chemical groupin which a double bondedcarbon structure isavailable forfree-radicalattack.One primer which may beused isgamma-Methacryloxypropyltrimethoxysilane,which is sold under thetrademark "Z-6030" by DowCorning of Midland Mich.The amount of primer usedmay vary widely dependingon the particularapplication. In variousexperiments withsuccessful results, theamount ofprimer used varied from0.1 to 1.0 phr.The final element of thecomposition of the presentinvention is a hinderedamine light stabilizer(also known as "HALS")selected from the groupconsisting ofO,O-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl)mono-peroxycarbonate andPoly[(4-hydroxy-2,2,6,6-tetramethyl-1-piperidine-ethanol) -co-dimethylsuccinate]. The completechemical characteristicsof these two compounds,along with other testedHALS compounds, aredisclosed on the attachedTable 1. As indicated onTable 1, these two HALScompounds arerespectively sold underthe trademarks"LUPERSOLHA-505" byAtochem and"TINUVIN 622LD" byCiba-Geigy Corporation ofHawthorne, N.Y.As indicated from Table I,the LUPERSOL HA-505 HALSactually representsO,O-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl) mono-peroxycarbonateina fifty percent mixturewith a solvent sold underthe trademark"AROMATIC-100" solvent byShell ChemicalCorporation. The"AROMATIC-100"solvent by Shell ChemicalCorporation consistsprimarily of meta-xylene,para-xylene, ethylbenzene and similarcompounds. It isformulated to be anon-oxygenated highboiling point solvent forcompatibility withacrylicpolymers for automotive topcoats.TABLE 1______________________________________COMMERCIAL HINDERED AMINE LIGHTSTABILIZERS("HALS" Type Stabilizers) Compound Chemistry______________________________________Ciba-Geigy CorporationHawthorne, NY1. TinuvinBis-(Tetramethyl piperidinyl sebacate)770 m.w. = 481, m.p. = 84° C., pKb = 5.0, pKa = 9.0 TMP = 63%2. TinuvinBis-(N-octyloxy-tetramet hyl piperidinyl123 sebacate), liquid, bp. = 367 C. at 760 mm;mw. = 737.2; pKb = 9.6; pKa = 4.2. TMP =41.2% Low basicity, claimed to be synergistic w/ benzotriazole UV absorbers.3. TinuvinPoly(4-hydroxy-tetramethyl piperidino-622D dimethyl succinate), m.w. = (283)n, Mn =>2500, m.p. = 60° C., pKa = 6.5, TMP =53.7%4. ChimassorbComplex polymer ofs-triazine with944FL (tetramethyl-piperidinyl)amino adipatem.w. = (579)n, Mn = >2500,m.p. = 55-70° C.pKa = 9.7, TMP = 52.5%American CyanamidBridgewater, New Jersey1. Cyasorb Oligomer ofN,N'-Bis(tetramethylUV-3346 piperidinyl)1,6-hexanediamine w/dichloromorpholinyl-triazine.M.W = appx. 1600, m.p. =110° C.-130° C.Moderately strong base.Recommended forEVA, and olefinsrequiring extendedweatherability.2. Cyasorb ProprietaryHALS (liquid), mw. = 406.6,UV-3581 b.p. = 212°C./0.7 torr. Moderatelystrongbase, pH = 8.13. CyasorbDodecyl-N-(1,2,2,6,6-pentamethyl-4-UV-3604piperidinyl)-succinimide(liquid),mw. = 420.66, bp. = 220C./0.7 torr; pH = 7.5,TMP = 72.3%4. Cyasorb Proprietaryexperimental HALS(liquid),UV-3668 mw. = 448.67, b.p.= n/a, pH = n/aLow basicityAtochem/Lucidol(previously PennwaltCorporation)Buffalo, New York1. Lupersol(Pentamethyl-4-piperidinyl)-O,O-t-Amyl-HA-505 monoperoxycarbonate, assay: 50%,remainder"Aromatic 100" solvent.Liquid, 32° F.storage required. M.W. =301, m.p. -13° F.TMP = 50.4% Reactive withpolymers;chemically binds HALSgroup.2. Luchem (Tetramethylpiperidinyl)-methylHA-B-phthalimido-oxamide. NOTreactive withHMPA polymer, but haspowerful metaldeactivation properties;m.w. = 392,m.p. = 115° C., TMP =38.7%______________________________________Note:"TMP" indicates theweight percent of thecompound that is theactivetetramethyl piperidinylgroup; the basis if HALSstabilization chemistry.*Material Safety DataSheets (MSDS) areavailable for all thecompoundsinvestigated in thisstudy.Before the utility ofthese two HALS compoundswas discovered, ananalysisof the causes ofencapsulant discolorationwas performed. An initialassumption was made thatthermal exposure, which isan unavoidablecondition for a solar cell,is the dominant stress onthe encapsulationsystem.Although light inducedreactions may alsoaggravate degradation,they aremore difficult toincorporate into testchambers, and much moredifficultto interpret. Regardlessof the relative importancebetween thermaldiscoloration and photodiscoloration, it can besaid that an encapsulantin accordance with thepresent invention reducesoverall discoloration byreducing thediscoloration fromexposure to heat.It was discovered that thethermal discoloration ofEVA is stronglycatalyzed by the presenceof oxygen. Therefore,compounds which interferewith oxygen radicalreactions should improvethe stability of the EVA.Some of the known causes ofdegradation of EVApolymers are shown belowonTable 2.TABLE 2________________________ ________________________ ________________________ __GENERALIZED EVA DEGRADATION PATHWAYS________________________ ________________________ ________________________ __Path 1. Conjugation: (discoloration)##STR1##Path 2.Absorption/Excitation: ##STR2##Path 3. Free-radical Formation:##STR3##Path 4. Reactions with Oxygen (Peroxidation): ##STR4##Path 5. Hydroperoxidation:##STR5##Path 6. Hydroperoxide Scission/Free-Radical Generation:##STR6##Path 7. Norrish Degradation:##STR7##________________________ ________________________ ________________________ __Although Table 2 represents a highly generalized scheme, it does provide some useful guidance. Forexample, the reactions ofall seven paths areinteractive with eachother and may eitherincrease or decrease theirrespective rates, as wellas cause each other torepeat. These reactionsmay, therefore, becompetitive.As stated above, one of thekey discoveries is thatthe thermaldiscoloration of EVA isstrongly catalyzed by thepresence of oxygen.Accordingly, several HALScompounds, which arepowerful antioxidants andfree radical traps, werestudied to determine theireffect ondiscoloration.HALS compounds are a classof compounds, known in theart, which are usedspecifically for thepurpose of stabilizingpolymers. They are usuallytertiary amines, but insome cases may besecondary amines. HALScompoundsare effective compoundsfor interrupting a numberof pathways of thermaldegradation. For example,HALS compounds interruptPath 3 (of Table 2) byradical scavenging, Path 2by excited state quenchingand Path 6 byperoxide decomposition.Additionally, HALScompounds offer thefollowingadvantages:1. HALS compounds do notinterfere with the curechemistry of EVA;2. Very highconcentrations of HALScompounds are possible formaximumlifetime;3. HALS compounds havevery high "molarefficiency" asantioxidants;4. HALS compounds arenon-sacrificial andregenerate themselves in acyclical process, known inliterature as the DenisovCycle, as discussedbelow;5. There may be asynergistic behavior ofcertain UV screeningadditives,in which the UV screen isprotected by the HALScompound; and6. Most HALS compoundshave low volatility andtwo compounds (one for EVA)are available that willchemically graft to thepolymer backbones duringcure.Regarding item 4, HALScompounds, as free radicalscavengers, participatein a cyclic chemicalprocess in which theyregenerate themselves.Themechanism ofstabilization andregeneration is stilldisputed, but ageneral theoretical modelappears to be correct.This theoretical modelindicates that thehindered amine (>N--H)oxides form nitroxylradicals(>N--O.), which in turnreact with polymerfree-radicals (P.) toform an amine-ether,thereby terminating theradical reaction. Theamine-ether then goes onto decomposepolymer-bound peroxyradicals,terminating anotherdegradation reaction andregenerating the nitroxylgroup again. The nitroxylgroup then repeats thisprocess, which is knownas the Denisov cycle (asmodified by Klemchuck)shown as follows in Table3:TABLE 3______________________________________##STR8##______________________________________HALS compounds areavailable as low molecular weight compounds, polymers,and as co-reactive compounds. The source and description of some HALS which were tested is given in Table 1, with some chemical structures being shown in Table 4. Commercially available compounds vary in: (a) molecularweight, (b) base strength (pH), and (c) the ability to graft to thepolymer backbone.TABLE 4________________________ ________________________ ________________________ __CHEMICAL STRUCTURESHINDERED AMINE LIGHT STABILIZERS; - Tinuvin 144##STR9##Tinuvin 770##STR10##Tinuvin 765##STR11##Tinuvin 123##STR12##Tinuvin 622 D##STR13##Chimassorb 944FL##STR14##Lupersol HA-505##STR15##LUCHEM HA-B-HMPA##STR16##________________________ __________________________________________________The molecular weight ofthe HALS compound controlsvolatility, solubilityand diffusion. The rate ofdiffusion frequentlycorrelates to theeffectiveness of theantioxidants, as it mustdiffuse to the chemicalsitewhere it is needed. Thisnormally limits theeffectiveness ofchemicallybound additives; however,some recent work onpolymer bound HALScompoundsshows some improvementover monomeric species,especially in combinationwith phenolic typeantioxidants.The basicity (pH, orcorrectly, pKa) of HALScompounds is now believedtohave a strong influence onstabilization. Stronglybasic HALS compoundsmay have an antagonisticreaction with acidiccomponents in polymerformulations. Lowerbasicity means lessinteraction withprotonatedspecies (acids). Stronglybasic HALS compounds inacidic environments mayprotonate at the aminenitrogen and form inactivequarternary ammoniumsalts, with no stabilizingactivity at all. However,tests confirming thishypothesis have not yetbeen conducted.Only one HALS compoundthat may reactivelycombine with EVA isavailable,manufactured by AtochemCorporation, Buffalo, NewYork. This chemicalcompound is sold under thetrademark "LUPERSOLHA-505", and is shown inTables 1 and 4. Thismaterial likely reactswith EVA during cure togive apolymerically boundstabilizer.The second reactive HALS,sold under the trademark"LUCHEM HA-RiO0", isdesigned to react onlywith maleate modifiedresins and is consequentlyofno use in EVA systems. Itis the basis of a relatedcompound, however,sold under the trademark"HA-B18" which is designedto be compatible withother polyolefins. It maybe of possible benefit inEVA resins.A caution is that theevaluation of HALSstabilizers by certainacceleratedaging devices, e.g. lamps,may underrate theirperformance. This may bedue to an unrealisticallylarge number of radicalsbeing generated whichmay kinetically "swamp"the stabilizer. Foraccuracy, thesestabilizersshould be evaluated byactual field trials. Dueto the differing kineticrates of radicaltermination, a mixture oftwo HALS may even bedesirable.One may function better athigher temperatures, andthe other moreeffectively at lowertemperatures.The method ofencapsulating a solar cellaccording to the presentinventioninvolves first mixing theelements together. Theelements include an EVAcopolymer, a curing agentand an HALS. Alternatively,if the selectedhindered amine lightstabilizer isO,O-t-Amyl-O-(1,2,2,6,6-Pentamethyl-4-piperidinyl) mono-peroxycarbonate,the curing agent need notbe included. These areincorporated byconventional milling andcompounding operations asare other additives.Then, this mixture isapplied to a solar cell ina conventional manner,such as by molding.Finally, the applied。