(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2014/0315016 A1
`(43) Pub. Date:
`Oct. 23, 2014
`Dollase et al.
`
`US 20140315016A1
`
`(54)
`
`(71)
`
`(72)
`
`ADHESIVE SUBSTANCE, IN PARTICULAR
`FORENCAPSULATING AN ELECTRONIC
`ASSEMBLY
`
`Applicant: tesa SE. Hamburg (DE)
`
`Inventors: Thilo Dollase, Hamburg (DE); Thorsten
`Krawinkel, Hamburg (DE); Minyoung
`Bai, Hamburg (DE)
`
`(21)
`
`Appl. No.:
`
`14/351,800
`
`(22)
`
`PCT Filed:
`
`Oct. 19, 2012
`
`(86)
`
`PCT NO.:
`S371 (c)(1),
`(2), (4) Date:
`
`PCT/EP2012/070779
`
`Apr. 14, 2014
`
`Foreign Application Priority Data
`
`(30)
`Oct. 21, 2011 (DE) ...................... 10 2011 O85 030.9
`Feb. 16, 2012 (DE) ...................... 10 2012 202 377.1
`
`Publication Classification
`
`(2006.01)
`(2006.01)
`(2006.01)
`
`(51) Int. Cl.
`HOIL 23/29
`C09J 7/02
`C09. I53/00
`(52) U.S. Cl.
`CPC ............. HOIL 23/293 (2013.01); C09J 153/00
`(2013.01); C09J 7/0221 (2013.01); C09J
`2203/326 (2013.01); C09J 2453/00 (2013.01)
`USPC ......... 428/339; 522/109; 428/355 EP; 427/58
`ABSTRACT
`(57)
`An adhesive and method for encapsulating an electronic
`arrangement with respect to permeants, wherein the adhesive
`and method have (a) at least one copolymer comprising at
`least isobutylene or butylene as comonomer kind and at least
`one comonomer kind which, considered as hypothetical
`homopolymer, has a softening temperature of greater than
`40°C., (b) at least one kind of an at least partly hydrogenated
`tackifier resin, (c) at least one kind of a reactive resin based on
`cyclic ethers having a softening temperature of less than 40°
`C., preferably less than 20°C., and (d) at least one kind of a
`photoinitiator for initiating cationic curing
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`Ex.1009
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`Patent Application Publication
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`Oct. 23, 2014 Sheet 2 of 2
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`US 2014/031501.6 A1
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`US 2014/031501.6 A1
`
`Oct. 23, 2014
`
`ADHESIVE SUBSTANCE, IN PARTICULAR
`FORENCAPSULATING AN ELECTRONIC
`ASSEMBLY
`0001. The present invention relates to an adhesive particu
`larly for encapsulating an electronic arrangement.
`0002 (Opto)electronic arrangements are being used with
`ever-increasing frequency in commercial products or are
`close to market introduction. Such arrangements comprise
`organic or inorganic electronic structures, examples being
`organic, organometallic or polymeric semiconductors or else
`combinations of these. Depending on the desired application,
`these arrangements and products are rigid or flexible inform,
`there being an increasing demand for flexible arrangements.
`Arrangements of this kind are produced, for example, by
`printing techniques, such as relief, gravure, Screen or plano
`graphic printing, or elsewhat is called “non-impact printing.
`Such as, for instance, thermal transfer printing, inkjet printing
`or digital printing. In many cases, however, vacuum tech
`niques are used as well. Such as chemical vapour deposition
`(CVD), physical vapour deposition (PVD), plasma-enhanced
`chemical or physical deposition techniques (PECVD), sput
`tering, (plasma) etching or vapour coating, with patterning
`taking place generally through masks.
`0003. Examples of (opto)electronic applications that are
`already commercial or are of interest in terms of their market
`potential include electrophoretic or electrochromic construc
`tions or displays, organic or polymeric light-emitting diodes
`(OLEDs or PLEDs) in readout and display devices, or as
`illumination, electroluminescent lamps, light-emitting elec
`trochemical cells (LEECs), organic solarcells, preferably dye
`or polymer Solar cells, inorganic Solar cells, preferably thin
`film Solar cells, more particularly those based on silicon,
`germanium, copper, indium and/or selenium, organic field
`effect transistors, organic Switching elements, organic optical
`amplifiers, organic laser diodes, organic or inorganic sensors
`or else organic- or inorganic-based RFID transponders.
`0004. A perceived technical challenge for realization of
`Sufficient lifetime and function of (opto)electronic arrange
`ments in the area of organic and/or inorganic (opto)electron
`ics, especially in the area of organic (opto)electronics, is the
`protection of the components they contain against permeants.
`Permeants may be a large number of low molecular mass
`organic or inorganic compounds, more particularly water
`Vapour and oxygen.
`0005. A large number of (opto)electronic arrangements in
`the area of organic and/or inorganic (opto)electronics, espe
`cially where organic raw materials are used, are sensitive not
`only to water vapour but also to oxygen, and for many
`arrangements the penetration of water vapour is classed as a
`relatively severe problem. During the lifetime of the elec
`tronic arrangement, therefore, it requires protection by means
`of encapsulation, since otherwise the performance drops off
`over the period of application. For example, oxidation of the
`components, in the case of light-emitting arrangements such
`as electroluminescent lamps (EL lamps) or organic light
`emitting diodes (OLEDs) for instance, may drastically reduce
`the luminosity, the contrast in the case of electrophoretic
`displays (EP displays), or the efficiency in the case of solar
`cells, within a very short time.
`0006. In organic and/or inorganic (opto)electronics, par
`ticularly in the case of organic (opto)electronics, there is a
`particular need for flexible bonding solutions which consti
`tute a permeation barrier to permeants. Such as oxygen and/or
`water vapour. In addition there are a host of further require
`
`ments for Such (opto)electronic arrangements. The flexible
`bonding solutions are therefore intended not only to achieve
`effective adhesion between two substrates, but also, in addi
`tion, to fulfil properties such as high shear strength and peel
`strength, chemical stability, ageing resistance, high transpar
`ency, ease of processing, and also high flexibility and pliabil
`ity.
`0007. One approach common in the prior art, therefore, is
`to place the electronic arrangement between two Substrates
`that are impermeable to water vapour and oxygen. This is then
`followed by sealing at the edges. For non-flexible construc
`tions, glass or metal Substrates are used, which offer a high
`permeation barrier but are very susceptible to mechanical
`loads. Furthermore, these substrates give rise to a relatively
`high thickness of the arrangement as a whole. In the case of
`metal Substrates, moreover, there is no transparency. For flex
`ible arrangements, in contrast, sheetlike Substrates are used,
`Such as transparent or non-transparent films, which may have
`a multi-ply configuration. In this case it is possible to use not
`only combinations of different polymers, but also organic or
`inorganic layers. The use of such sheetlike Substrates allows a
`flexible, extremely thin construction. For the different appli
`cations there are a very wide variety of possible substrates,
`Such as films, wovens, nonwovens and papers or combina
`tions thereof, for example.
`0008. In order to obtain the most effective sealing, specific
`barrier adhesives are used. A good adhesive for the sealing of
`(opto)electronic components has a low permeability for oxy
`gen and particularly for water vapour, has sufficient adhesion
`to the arrangement, and is able to flow well onto the arrange
`ment. Owing to incomplete wetting of the Surface of the
`arrangement and owing to pores that remain, low capacity for
`flow on the arrangement may reduce the barrier effect at the
`interface, since it permits lateral ingress of oxygen and water
`vapour independently of the properties of the adhesive. Only
`if the contact between adhesive and substrate is continuous
`are the properties of the adhesive the determining factor for
`the barrier effect of the adhesive.
`0009 For the purpose of characterizing the barrier effect it
`is usual to state the oxygen transmission rate OTR and the
`water vapour transmission rate WVTR. Each of these rates
`indicates the flow of oxygen or water vapour, respectively,
`through a film per unit area and unit time, under specific
`conditions of temperature and partial pressure and also,
`optionally, further measurement conditions such as relative
`atmospheric humidity. The lower the values the more suitable
`the respective material for encapsulation. The statement of
`the permeation is not based solely on the values of WVTR or
`OTR, but instead also always includes an indication of the
`average path length of the permeation, Such as the thickness
`of the material, for example, or a standardization to a particu
`lar path length.
`0010. The permeability P is a measure of the perviousness
`of a body for gases and/or liquids. A low P values denotes a
`good barrier effect. The permeability P is a specific value for
`a defined material and a defined permeant under steady-state
`conditions and with defined permeation path length, partial
`pressure and temperature. The permeability P is the product
`of diffusion term D and solubility term S:
`P=D:S
`0011. The solubility term S describes in the present case
`the affinity of the barrier adhesive for the permeant. In the
`case of water vapour, for example, a low value for S is
`
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`achieved by hydrophobic materials. The diffusion term D is a
`measure of the mobility of the permeant in the barrier mate
`rial, and is directly dependent on properties, such as the
`molecular mobility or the free volume. Often, in the case of
`highly crosslinked or highly crystalline materials, relatively
`low values are obtained for D. Highly crystalline materials,
`however, are generally less transparent, and greater crosslink
`ing results in a lower flexibility. The permeability P typically
`rises with an increase in the molecular mobility, as for
`instance when the temperature is raised or the glass transition
`point is exceeded.
`0012. A low solubility term S is usually insufficient for
`achieving good barrier properties. One classic example of
`this, in particular, are siloxane elastomers. The materials are
`extraordinarily hydrophobic (low solubility term), but as a
`result of their freely rotatable Si-O bond (large diffusion
`term) have a comparatively low barrier effect for water
`vapour and oxygen. For a good barrier effect, then, a good
`balance between solubility term S and diffusion term D is
`necessary.
`0013 Approaches at increasing the barrier effect of an
`adhesive must take account of the two parameters D and S.
`with a view in particular to their influence on the permeability
`of water vapour and oxygen. In addition to these chemical
`properties, thought must also be given to consequences of
`physical effects on the permeability, particularly the average
`permeation path length and interface properties (flow-on
`behaviour of the adhesive, adhesion). The ideal barrier adhe
`sive has low D values and S values in conjunction with very
`good adhesion to the Substrate.
`0014 For this purpose use has hitherto been made in par
`ticular of liquid adhesives and adhesives based on epoxides
`(WO 98/21287 A1; U.S. Pat. No. 4,051, 195A; U.S. Pat. No.
`4.552,604 A). As a result of a high degree of crosslinking,
`these adhesives have a low diffusion term D. Their principal
`field of use is in the edge bonding of rigid arrangements, but
`also moderately flexible arrangements. Curing takes place
`thermally or by means of UV radiation. Full-area bonding is
`hard to achieve, owing to the contraction that occurs as a
`result of curing, since in the course of curing there are stresses
`between adhesive and substrate that may in turn lead to
`delamination.
`0015 Using these liquid adhesives harbours a series of
`disadvantages. For instance, low molecular mass constituents
`(VOCs—volatile organic compounds) may damage the sen
`sitive electronic structures in the arrangement and may hinder
`production operations. The adhesive must be applied, labori
`ously, to each individual constituent of the arrangement. The
`acquisition of expensive dispensers and fixing devices is nec
`essary in order to ensure precise positioning. Moreover, the
`nature of application prevents a rapid continuous operation,
`and the laminating step that is Subsequently needed may also
`make it more difficult, owing to the low viscosity, to achieve
`a defined layer thickness and bond width within narrow lim
`its.
`0016 Furthermore, the residual flexibility of such highly
`crosslinked adhesives after curing is low. In the low tempera
`ture range or in the case of 2-component systems, the use of
`thermally crosslinking systems is limited by the potlife, in
`other words the processing life until gelling has taken place.
`In the high temperature range, and particularly in the case of
`long reaction times, in turn, the sensitive (opto)electronic
`structures limit the possibility of using Such systems—the
`maximum temperatures that can be employed in the case of
`
`(opto)electronic structures are often 60°C., since above even
`this temperature there may be initial damage. Flexible
`arrangements which comprise organic electronics and are
`encapsulated using transparent polymer films or assemblies
`of polymer films and inorganic layers, in particular, have
`narrow limits here. The same applies to laminating steps
`under high pressure. In order to achieve improved durability,
`it is advantageous here to forgo a temperature loading step
`and to carry out lamination under a relatively low pressure.
`0017. As an alternative to the thermally curable liquid
`adhesives, radiation-curing adhesives as well are now used in
`many cases (US 2004/0225025 A1). The use of radiation
`curing adhesives prevents long-lasting thermal load on the
`electronic arrangement.
`0018 Particularly if the (opto)electronic arrangements are
`to be flexible, it is important that the adhesive used is not too
`rigid and brittle. Accordingly, pressure-sensitive adhesives
`(PSAs) and heat-activatedly bondable adhesive sheets are
`particularly suitable for such bonding. In order to flow well
`onto the Substrate but at the same time to attaina high bonding
`strength, the adhesives ought initially to be very soft, but then
`to be able to be crosslinked. As crosslinking mechanisms it is
`possible, depending on the chemical basis of the adhesive, to
`implement thermal cures and/or radiation cures. While ther
`mal curing is very slow, radiation cures can be initiated within
`a few seconds. Accordingly, radiation cures, more particu
`larly UV curing, are preferred, especially in the case of con
`tinuous production processes.
`0019. DE 10 2008 060 113 A1 describes a method for
`encapsulating an electronic arrangement with respect to per
`meants, using a PSA based on butylene block copolymers,
`more particularly isobutylene block copolymers, and
`describes the use of Such an adhesive in an encapsulation
`method. In combination with the elastomers, defined resins,
`characterized by DACP and MMAP values, are preferred.
`The adhesive, moreover, is preferably transparent and may
`exhibit UV-blocking properties. As barrier properties, the
`adhesive preferably has a WVTR of <40 g/m"d and an OTR
`of <5000 g/m·d bar. In the method, the PSA may be heated
`during and/or after application. The PSA may be
`crosslinked by radiation, for example. Classes of Substance
`are proposed via which Such crosslinking can be advanta
`geously performed. However, no specific examples are given
`that lead to particularly low Volume permeation and interfa
`cial permeation in conjunction with high transparency and
`flexibility.
`(0020 EP 1518 912 A1 teaches an adhesive for encapsu
`lating an electroluminescent element which comprises a pho
`tocationically curable compound and a photocationic initia
`tor. Curing takes place as a dark reaction following light
`stimulation. The adhesive is preferably epoxy-based. Ali
`phatic hydroxides and polyethers may be added as
`co-crosslinking components. Moreover, a tackifier resin may
`be present in order to adjust adhesion and cohesion. This may
`also include polyisobutylene. No specific information is
`given regarding the compatibility of the individual constitu
`ents, and there are also no indications of the molar masses of
`the polymers.
`(0021 JP 4,475,084 B1 teaches transparent sealants for
`organic electroluminescent elements, that may be based on
`block copolymer. Examples listed are SIS and SBS and also
`the hydrogenated versions. Not specified, however, are con
`stituents which permit crosslinking after application. Nor are
`
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`US 2014/031501.6 A1
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`Oct. 23, 2014
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`the barrier properties of the sealants addressed. The sealing
`layer apparently does not take on any specific barrier func
`tion.
`0022 US 2006/100299 A1 discloses a PSA which com
`prises a polymer having a softening temperature, as defined in
`US 2006/100299 A1, ofgreater than +60° C., a polymerizable
`resin having a softening temperature, as defined in US 2006/
`100299 A1 of less than +30°C., and an initiator which is able
`to lead to a reaction between resin and polymer. Reactively
`equipped polymers, however, are not available universally,
`and so there are restrictions on the selection of this polymer
`basis when other properties and costs are an issue. Moreover,
`any kind of functionalization (for the purpose of providing
`reactivity) is accompanied by an increase in basic polarity and
`hence by an unwanted rise in water vapour permeability. No
`copolymers based on isobutylene or butylene are identified,
`and no information is given on molar masses of the polymers.
`0023 US 2009/026934 A1 describes layers of adhesive
`for the encapsulation of organic electroluminescent elements.
`The adhesives comprise polyisobutylene and a hydrogenated
`hydrocarbon resin. For crosslinking after application it is
`possible to use various reactive resins, including epoxides.
`WVTR values in the examples are typically between 5 and 20
`g/m·d. OTR values are not stated. As copolymerit is possible
`to utilize polyisobutylene polymers, generated by copolymer
`ization with other soft monomers. The molar masses of the
`polymers are typically >500 000 g/mol.
`0024 WO 2008/144080 A1 teaches constructions with
`sensitive organic layers that are encapsulated. Encapsulation
`takes place by a cured elastomeric laminating adhesive.
`Adhesives employed are mixtures of reactive oligomers and/
`or polymers and reactive monomers. Curing may be accom
`plished via radiation or heat. The reactivity, according to the
`description, is introduced via (meth)acrylate groups. Cationic
`curing of epoxy resins is not mentioned explicitly. Copoly
`mers as an elastomer basis are not specified, and nor is any
`information given concerning molar masses of the polymers.
`0025 US 2010/013.7530 A1 discloses curable adhesive
`layers based on epoxy resin mixtures. One kind of epoxy resin
`has a low molar mass, another kind a relatively high molar
`mass. Cationic curing is carried out, initiated by UV. No
`elastomer base is provided.
`0026. It is an object of the invention to provide an adhesive
`which is able to prevent the harmful influence of oxygen and
`water vapour on sensitive functional layerS Such as, for
`example, in the area of organic photoelectric cells for Solar
`modules, or in the area of organic light-emitting diodes
`(OLEDs), by means of a good barrier effect with respect to the
`harmful substances; which is able to join different compo
`nents of the functional elements to one another, which is
`readily manageable in adhesive bonding operations; which
`allows a flexible and tidy processing; and which is neverthe
`less easy to use for the producer.
`0027. This object is achieved by means of an adhesive as
`characterized in more detail in the main claim. The dependent
`claims describe advantageous embodiments of the invention.
`Also encompassed is the use of the adhesive of the invention.
`0028. The invention accordingly provides an adhesive,
`preferably a pressure-sensitive adhesive, comprising
`0029 (a) at least one copolymer comprising at least
`isobutylene or butylene as comonomer kind and at least
`one comonomer kind which—considered as hypotheti
`cal homopolymer—has a softening temperature of
`greater than 40°C.,
`
`0030 (b) at least one kind of an at least partly hydroge
`nated tackifier resin,
`0.031
`(c) at least one kind of a reactive resin based on a
`cyclic ether having a softening temperature of less than
`40° C., preferably of less than 20° C.
`0.032
`(d) at least one kind of a photoinitiator for initi
`ating cationic curing.
`0033. In the case of amorphous substances, the softening
`temperature here corresponds to the glass transition tempera
`ture; in the case of (semi-)crystalline Substances, the soften
`ing temperature here corresponds to the melting temperature.
`0034. In the adhesives sector, pressure-sensitive adhesives
`(PSAs) are notable in particular for their permanent tack and
`flexibility. A material which exhibits permanent pressure
`sensitive tack must at any given point in time feature a Suitable
`combination of adhesive and cohesive properties. For good
`adhesion properties it is necessary to formulate PSAs for an
`optimum balance between adhesive and cohesive properties.
`0035. The adhesive is preferably a PSA, in other words a
`Viscoelastic mass which remains permanently tacky and
`adhesive in the dry state at room temperature. Bonding is
`accomplished by gentle applied pressure, immediately, to
`virtually every substrate.
`0036. According to one preferred embodiment of the
`invention, the copolymer or copolymers is or are random,
`alternating, block, star and/or graft copolymers having a
`molar mass M (weight average) of 300 000 g/mol or less,
`preferably 200 000 g/mol or less. Smaller molar weights are
`preferred here on account of their better processing qualities.
`0037 Copolymers used are, for example, random copoly
`mers of at least two different monomer kinds, of which at least
`one is isobutylene or butylene and at least one other is a
`comonomer having viewed as hypothetical homopoly
`mer—a softening temperature of greater than 40°C. Advan
`tageous examples of this second comonomer kind are viny
`laromatics (including partly or fully hydrogenated versions),
`methyl methacrylate, cyclohexyl methacrylate, isobornyl
`methacrylate and isobornyl acrylate.
`0038 Particularly preferred examples are styrene and
`a-methylstyrene, with this enumeration making no claim to
`completeness.
`0039. With further preference, the copolymer or copoly
`mers is or are block, star and/or graft copolymers which
`contain at least one kind of first polymer block (“soft block')
`having a softening temperature of less than -20° C. and at
`least one kind of a second polymer block (“hard block')
`having a softening temperature of greater than +40° C.
`0040. The soft block here is preferably apolar in construc
`tion and preferably comprises butylene or isobutylene as
`homopolymer block or copolymer block, the latterpreferably
`copolymerized with itself or with one another or with further
`comonomers, more preferably apolar comonomers.
`Examples of Suitable apolar comonomers are (partly) hydro
`genated polybutadiene, (partly) hydrogenated polyisoprene
`and/or polyolefins.
`0041. The hard block is preferably constructed from viny
`laromatics (including partly or fully hydrogenated versions),
`methyl methacrylate, cyclohexyl methacrylate, isobornyl
`methacrylate and/or isobornyl acrylate. Particularly preferred
`examples are styrene and a-methylstyrene, this enumeration
`making no claim to completeness. The hard block thus com
`prises the at least one comonomer kind which viewed as
`hypothetical homopolymer—has a softening temperature of
`greater than 40°C.
`
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`0042. In one particularly advantageous embodiment, the
`preferred soft blocks and hard blocks described are actualized
`simultaneously in the copolymer or copolymers.
`0043. It is advantageous if the at least one block copoly
`mer is a triblock copolymer constructed from two terminal
`hard blocks and one middle soft block. Diblock copolymers
`are likewise highly suitable, as are mixtures of triblock and
`diblock copolymers.
`0044. It is very preferred to use triblock copolymers of the
`polystyrene-block-polyisobutylene-block-polystyrene type.
`Systems of this kind have been disclosed under the names
`SIBStar from Kaneka and Oppanol IBS from BASF. Other
`systems which can be used advantageously are described in
`EP 1 743928A1.
`0045. The fact that the copolymers include a fraction of
`isobutylene or butylene as at least one comonomer kind
`results in anapolar adhesive which offers advantageously low
`volume barrier properties especially with respect to water
`vapour.
`0046. The low molar masses of the copolymers, in contrast
`to the prior art, permit good processing properties for the
`producer, especially in formulating and coating operations.
`Low molar mass leads to better and faster solubility, if sol
`vent-based operations are desired (for isobutylene polymers
`and butylene polymers particularly, the selection of suitable
`Solvents is Small). Moreover, higher copolymer concentra
`tions in the solution are possible. In solvent-free operations as
`well, an inventively low molar mass proves to be an advan
`tage, since the melt viscosity is lower than with comparative
`systems of higher molar mass.
`0047 Merely reducing the molar mass does lead, of
`course, to better solubility and lower solution and melt vis
`cosities. However, with the lower molar mass, there is detri
`ment to other properties important from a performance stand
`point, such as the cohesion of an adhesive, for example. Here,
`the inventive use of the at least second comonomer kind, with
`the softening temperature, for a hypothetical homopolymer,
`of more than 40°C., is an effective counter.
`0048. The adhesive of the invention comprises at least one
`kind of an at least partly hydrogenated tackifier resin, advan
`tageously of the sort which are compatible with the copoly
`mer or, where a copolymer constructed from hard blocks and
`soft blocks is used, compatible primarily with the soft block
`(Soft resins).
`0049. It is advantageous if this tackifier resin has a tacki
`fier resin softening temperature of greater than 25°C. It is
`advantageous, furthermore, if additionally at least one kind of
`tackifier resin having a tackifier resin softening temperature
`of less than 20° C. is used. In this way it is possible, if
`necessary, to fine-tune not only the technical bonding behav
`iour but also the flow behaviour on the bonding substrate.
`0050 Resins in the PSA may be, for example, partially or
`fully hydrogenated resins based on rosin and rosin deriva
`tives, hydrogenated polymers of dicyclopentadiene, partially,
`selectively or fully hydrogenated hydrocarbon resins based
`on Cs, Cs/Co or Co. monomer Streams, polyterpene resins
`based on a-pinene and/or R-pinene and/or Ö-limonene, and
`hydrogenated polymers of preferably pure Cs and Co aromat
`ics. Aforementioned tackifier resins may be used either alone
`or in a mixture.
`0051. It is possible here to use both room-temperature
`Solid resins and liquid resins. In order to ensure high ageing
`
`stability and UV stability, hydrogenated resins with a degree
`of hydrogenation of at least 90%, preferably of at least 95%,
`are preferred.
`0.052
`Preference is given, furthermore, to apolar resins
`having a DACP (diacetone alcohol cloud point) of more than
`30° C. and an MMAP (mixed methylcylohexane aniline
`point) of greater than 50° C., more particularly having a
`DACP of more than 37° C. and an MMAP of greater than 60°
`C. The DACP and the MMAP each indicate the solubility in
`a particular solvent. Through the selection of these ranges, the
`resulting permeation barrier, especially with respect to water
`vapour, is particularly high.
`0053. The adhesive of the invention further comprises at
`least one kind of a reactive resin based on a cyclic ether, for
`radiation crosslinking and optionally thermal crosslinking,
`having a softening temperature of less than 40°C., preferably
`of less than 20° C.
`0054 The reactive resins based on cyclic ethers are more
`particularly epoxides, i.e. compounds which carry at least one
`oxirane group, or oxetanes. They may be aromatic or more
`particularly aliphatic or cycloaliphatic in nature.
`0055 Reactive resins that can be used may be monofunc
`tional, difunctional, trifunctional, tetrafunctional or of higher
`functionality up to polyfunctional, where the functionality
`relates to the cyclic ether group.
`0056. Examples, without any intention to impose a restric
`tion, are 3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexan
`ecarboxylate (EEC) and derivatives, dicyclopentadiene diox
`ide and derivatives, 3-ethyl-3-oxetanemethanol and
`derivatives, diglycidyl tetrahydrophthalate and derivatives,
`diglycidyl hexahydrophthalate and derivatives, 1.2-ethane
`diglycidyl ether and derivatives, 1,3-propane diglycidyl ether
`and derivatives, 1,4-butanediol diglycidyl ether and deriva
`tives, higher 1,n-alkane diglycidyl ethers and derivatives, bis
`(3.4-epoxycyclohexyl)methyl adipate and derivatives,
`vinylcyclohexyl dioxide and derivatives, 1,4-cyclohex
`anedimethanol bis(3,4-epoxycyclohexanecarboxylate) and
`derivatives, diglycidyl 4.5-epoxytetrahydrophthalate and
`derivatives, bis1-ethyl(3-oxetanyl)methyl ether and deriva
`tives, pentaerythrity1 tetraglycidyl ether and derivatives,
`bisphenol A diglycidyl ether (DGEBA), hydrogenated
`bisphenol A diglycidyl ether, bisphenol F diglycidyl ether,
`hydrogenated bisphenol F diglycidyl ether, epoxyphenol
`novolaks, hydrogenated epoxyphenol novolaks, epoxycresol
`novolaks, hydrogenated epoxycresol novolaks, 2-(7-Oxabi
`cyclospiro (1,3-dioxane-5.3'-(7-Oxabicyclo4.1.0 heptane)),
`1,4-bis(2,3-epoxypropoxy)-methyl)cyclohexane.
`0057 Reactive resins can be used in their monomeric form
`or else dimeric form, trimeric form, etc., up to and including
`their oligomeric form.
`0.058 Mixtures of reactive resins with one another, but
`also with other coreactive compounds such as alcohols
`(monofunctional or polyfunctional) or vinyl ethers (mono
`functional or polyfunctional) are likewise possible.
`0059. The adhesive formulation additionally comprises at
`least one kind of photoinitiator for the cationic curing of the
`reactive resins. Among the initiators for cationic UV curing,
`more particularly, Sulphonium-, iodonium- and metallocene
`based systems are usable.
`0060. As examples of sulphonium-based cations, refer
`ence is made to the details in U.S. Pat. No. 6,908,722 B1
`(especially columns 10 to 21).
`0061
`Examples of anions which serve as counterions to
`the abovementioned cations include tetrafluoroborate, tet
`
`Ex.1009
`APPLE INC. / Page 7 of 19
`
`

`

`US 2014/031501.6 A1
`
`Oct. 23, 2014
`
`raphenylborate, hexafluorophosphate, perchlorate, tetrachlo
`roferrate, hexafluoroarsenate, hexafluoroantimonate, pen
`tafluorohydroxyantimonate,
`hexachloro-antimonate,
`tetrakispentafluorophenylborate, tetrakis(pentafluorometh
`ylphenyl)borate, bi(trifluoromethylsulphonyl)amide and tris
`(trifluoromethylsulphonyl)methide. Additionally conceiv
`able as anions, especially for iodonium-based initiators, are
`also chloride, bromide or iodide, although preference is given
`to initiators essentially free of chlorine and bromine.
`0062 More specifically, the usable systems include
`0063 sulphonium salts (see, for example, U.S. Pat. No.
`4,231,951 A, U.S. Pat. No. 4,256,828 A, U.S. Pat. No.
`4,058,401 A, U.S. Pat. No. 4,138,255 A and US 2010/
`063221 A1) such as triphenylsulphonium hexafluoro
`arsenate, triphenylsulphonium hexafluoroborate, triph
`enylsulphonium tetrafluoroborate, triphenylsulphonium
`tetrakis(pentafluorobenzyl)borate, met