Background technology
For by adhesive layer by the optical member adhering such as Polarizer, polarizer liquid crystal cells etc. by adherend on, various adhesive films (for example,, with reference to patent documentation 1~2) have been proposed.
In patent documentation 1, record a kind of monomer using butyl acrylate etc. as main component, and the optics adhesive composition that contains acrylamide compound etc.
In patent documentation 2, recorded a kind of using have carbonatoms be (methyl) acrylate of 4~8 alkyl as main component monomer, and the optics adhesive composition that contains carboxylic monomer and nitrogenous vinyl monomer.
In addition, in order to improve the specific refractory power of adhesive layer, through repeatedly having researched and proposed multiple adhesive film (for example,, with reference to patent documentation 3~8).
In patent documentation 3, record and a kind ofly there is aromatic ring and contain the optics adhesive composition that specific refractory power is 1.51~1.75 tackifier.
In patent documentation 4, recorded a kind of bonding sheet having used containing the adhesive composition of copolymerizable polymkeric substance, described copolymerizable polymkeric substance is the copolymerizable polymkeric substance containing the acrylic acid modified monomer of aromatic ring.
In patent documentation 5, having recorded a kind of containing has the tackifying resin of aromatic ring and the optics adhesive composition of aromatic phosphoric ester class softening agent.
In patent documentation 6, recorded a kind of binding agent forming that solidified by adhesive composition, described adhesive composition comprises: acrylic resin; And containing the aromatics of an ethene unsaturated group.
In patent documentation 7, recorded a kind of by containing the acrylic adhesive of aromatic monomer by phase retardation film and the birefringent plate optical element forming that interfixes.
In patent documentation 8, recorded a kind of adhesive composition that contains urethane resin, described urethane resin is that aromatic diisocyanate and the reaction of aromatic polyester glycol are formed.
In recent years, in order to realize the filming of optics, requiring the adhesive film of fitting for the interlayer of optics is that adhesive layer is the adhesive film of the following thin layer of thickness 20 μ m.
Conventionally, the cohesive force of adhesive layer and the thickness of adhesive layer are roughly proportional, therefore, if by the thickness attenuation of adhesive layer, can reduce cohesive force thereupon.
But, require in recent years adhesive film to there is following performance: even by the thickness attenuation of adhesive layer, also there is the cohesive force equal with adhesive film (adhesive layer is the thick-layer that thickness is about 30 μ m) in the past, and for the weather resistance after long-time placement under high temperature, high humidity environment, also have and the equal above performance of adhesive film in the past.
In addition, from can and forming the viewpoint without the adhesive layer of enforcement ageing treatment (implementing slaking under constant temperature) by the thickness attenuation of adhesive layer, requirement is formed as NCF(Non Carrier Film, non-bearing film) form, it has parts adhesive layer, " mold release film/adhesive layer/mold release film " that comprise after the base material that has removed adhesive film and forms.
In addition, in adhesive film in the past, owing to implementing ageing treatment after the adhesive film of fitting on by adherend, therefore, can improve by the tack between adherend and adhesive layer.
But the adhesive film of employing NCF form has completed the ageing treatment of adhesive layer, therefore by the tack deficiency between adherend and adhesive layer.Based on this, existence need to be to being carried out the surface-treated problems such as corona treatment by the surface of adherend.
Therefore need a kind of adhesive film that meets these requirements and overcome these problems.
[prior art document]
[patent documentation]
[patent documentation 1] TOHKEMY 2012-177022 communique
[patent documentation 2] TOHKEMY 2012-201734 communique
[patent documentation 3] TOHKEMY 2007-084762 communique
[patent documentation 4] TOHKEMY 2011-153169 communique
[patent documentation 5] TOHKEMY 2012-167188 communique
[patent documentation 6] TOHKEMY 2012-021148 communique
[patent documentation 7] TOHKEMY 2006-293281 communique
[patent documentation 8] TOHKEMY 2009-091522 communique
Embodiment
Below, according to preferred embodiment the present invention will be described.
Adhesive layer of the present invention is crosslinked the forming of adhesive composition that makes to comprise acrylic polymers, wherein, more than described adhesive composition contains at least one in (methyl) alkyl acrylate monomer that alkyl carbon atoms number is C1~C14 as (methyl) acrylate monomer of main component and more than containing at least one in (methyl) acrylate monomer of aryl, and more than containing at least one in nitrogenous vinyl monomer as other copolymerization monomer, more than at least one in the copolymerization sex ethylene base monomer of carboxylic copolymerization sex ethylene base monomer and/or hydroxyl, and, the thickness of described adhesive layer is 1 μ m~20 μ m, cohesive force when thickness 5 μ m is 4.0(N/25mm) more than.
(methyl) alkyl acrylate monomer that is C1~C14 as alkyl carbon atoms number, can enumerate (methyl) methyl acrylate, (methyl) ethyl propenoate, (methyl) propyl acrylate, (methyl) isopropyl acrylate, (methyl) butyl acrylate, (methyl) isobutyl acrylate, (methyl) vinylformic acid pentyl ester, (methyl) Ethyl acrylate, (methyl) vinylformic acid heptyl ester, (methyl) Octyl acrylate, (methyl) Isooctyl acrylate monomer, (methyl) 2-EHA, (methyl) vinylformic acid ester in the ninth of the ten Heavenly Stems, (methyl) vinylformic acid ester in the different ninth of the ten Heavenly Stems, (methyl) decyl acrylate, (methyl) vinylformic acid undecyl ester, (methyl) dodecylacrylate, (methyl) tridecyl acrylate, (methyl) vinylformic acid tetradecyl ester, (methyl) vinylformic acid ring pentyl ester, more than at least one in (methyl) cyclohexyl acrylate etc.Alkyl in (methyl) alkyl acrylate monomer can be any one in straight chain, side chain, ring-type.With respect to acrylic polymers (multipolymer) 100 weight parts of binder composition, the ratio of (methyl) acrylate monomer that alkyl carbon atoms number is C1~C14 is preferably 50~95 weight parts.
As containing (methyl) acrylate monomer of aryl, can enumerate (methyl) benzyl acrylate, (methyl) vinylformic acid naphthalene ester, (methyl) phenoxyethyl acrylate, (methyl) vinylformic acid benzene oxygen butyl ester, (methyl) vinylformic acid 2-(1-naphthyloxy) ethyl ester, (methyl) vinylformic acid 2-(2-naphthyloxy) ethyl ester, (methyl) vinylformic acid 6-(1-naphthyloxy) own ester, (methyl) vinylformic acid 6-(2-naphthyloxy) own ester, (methyl) vinylformic acid 8-(1-naphthyloxy) monooctyl ester, (methyl) vinylformic acid 8-(2-naphthyloxy) monooctyl ester etc.In order to obtain the adhesive layer that specific refractory power is high, preferably coordinate at least more than one (methyl) acrylate monomer containing aryl.
By using these containing (methyl) acrylate monomers of aryl be that alkyl carbon atoms number is that (methyl) alkyl acrylate monomer of C1~C14 is mixed as the monomer of main component, can make the specific refractory power of obtained adhesive layer improve and adjust, reduce the refringence between optics, reduce total reflection, can improve thus total light transmittance.In adhesive layer of the present invention, when adhesive composition contains in the situation containing (methyl) acrylate monomer of aryl, its content, with respect to (methyl) acrylate monomer 100 weight parts as main component, is preferably 5~30 weight parts.
As nitrogenous vinyl monomer, for example, can enumerate the ring-type nitrogen vinyl compounds such as NVP, N-caprolactam, (methyl) acryloyl morpholine; N-ethyl-N-methyl (methyl) acrylamide, N-methyl-N-propyl group (methyl) acrylamide, N-methyl-N-isopropyl propyl group (methyl) acrylamide, N, N-dimethyl (methyl) acrylamide, N, N-diethyl (methyl) acrylamide, N, N-dipropyl (methyl) acrylamide, N, N-di-isopropyl (methyl) acrylamide, N, the dialkyl group such as N-dibutyl (methyl) acrylamide replace (methyl) acrylamide; (methyl) vinylformic acid N-ethyl-N-methyl ammonia ethyl ester, (methyl) vinylformic acid N-methyl-N-propyl group ammonia ethyl ester, (methyl) vinylformic acid N-methyl-N-isopropyl propyl group ammonia ethyl ester, (methyl) vinylformic acid N, N-dimethylamino methyl esters, (methyl) vinylformic acid N, N-dimethylamino ethyl ester, (methyl) vinylformic acid N, N-dimethylamino propyl ester, (methyl) vinylformic acid N, N-dimethylamino butyl ester, (methyl) vinylformic acid N, N-dipropyl ammonia ethyl ester, (methyl) vinylformic acid N, (methyl) propenoic acid dialkyl ammonia esters such as N-dibutylamine ethyl ester; N-ethyl-N-methyl aminopropyl (methyl) acrylamide, N-methyl-N-propyl group aminopropyl (methyl) acrylamide, N-methyl-N-isopropyl propyl group aminopropyl (methyl) acrylamide, N, N-dimethyl aminopropyl (methyl) acrylamide, N, N-diethyl amino propyl group (methyl) acrylamide, N, N-dipropyl aminopropyl (methyl) acrylamide, N, N-dimethylaminoethyl (methyl) acrylamide, N, more than at least one in dialkyl group substituted-amino alkyl (methyl) acrylamides such as N-diethyl aminoethyl (methyl) acrylamide etc.
In order to distinguish with the compound of aftermentioned (D), as above-mentioned nitrogenous vinyl monomer, preferably do not contain hydroxyl, more preferably do not contain hydroxyl and carboxyl.As this monomer, preferably above-mentioned illustrative monomer, for example, contains N, N-dialkyl group substituted-amino or N, the acrylic monomer of N-dialkyl group substituted amido; The N-vinyl substituted lactams such as NVP, N-caprolactam; N-(methyl) the N-(methyl such as acryloyl morpholine) acryl substituted cyclic amine.
In addition,, in adhesive layer of the present invention, the nitrogenous vinyl monomer that adhesive composition is contained, can give cohesive force and the weather resistance of adhesive layer necessity.In adhesive layer of the present invention, the content of the nitrogenous vinyl monomer containing in adhesive composition is preferably 5~50 weight parts with respect to (methyl) acrylate monomer 100 weight parts of main component.
In addition, in adhesive layer of the present invention, the nitrogenous vinyl monomer containing as adhesive composition, particularly preferably use NVP, N, N-dimethyl (methyl) acrylamide, N, N-diethyl (methyl) acrylamide, N, N-dipropyl (methyl) acrylamide, N, N-di-isopropyl (methyl) acrylamide, N, N-dibutyl (methyl) acrylamide, N, N-dimethyl aminopropyl (methyl) acrylamide, N, N-diethyl amino propyl group (methyl) acrylamide, N, N-dimethylaminoethyl (methyl) acrylamide, N-caprolactam etc.
As the copolymerization sex ethylene base monomer (monomer that contains carboxyl) that contains carboxyl, for example can enumerate (methyl) vinylformic acid, (methyl) vinylformic acid carboxylic ethyl ester, (methyl) vinylformic acid carboxylic pentyl ester, 2-(methyl) acryloxy ethyl hexahydrophthalic acid, 2-(methyl) acryloxy propyl group hexahydrophthalic acid, 2-(methyl) acryloxy ethyl phthalic acid, 2-(methyl) acryloxy ethyl succsinic acid, 2-(methyl) acryloxy ethyl toxilic acid, carboxyl polycaprolactone list (methyl) acrylate, 2-(methyl) more than at least one in acryloxy ethyl tetrahydrophthalic acid etc.
In addition,, in adhesive layer of the present invention, the contained carboxylic monomer of adhesive composition can be given the cohesive force of adhesive layer necessity.In adhesive layer of the present invention, the content of the carboxylic monomer containing in adhesive composition is preferably 0.1~5 weight part with respect to (methyl) acrylate monomer 100 weight parts of main component.
As the copolymerization sex ethylene base monomer (monomer of hydroxyl) of hydroxyl, for example can enumerate (methyl) vinylformic acid hydroxyalkyl acrylate classes such as (methyl) vinylformic acid 8-hydroxyl monooctyl ester, the own ester of (methyl) vinylformic acid 6-hydroxyl, (methyl) vinylformic acid 4-hydroxyl butyl ester, (methyl) Hydroxyethyl Acrylate, more than at least one in (methyl) acrylic amide of the hydroxyls such as N-hydroxyl (methyl) acrylamide, N-methylol (methyl) acrylamide, N-hydroxyethyl (methyl) acrylamide etc.
In addition, in adhesive layer of the present invention, the monomer of the hydroxyl that adhesive composition contains is to use as the copolymerization monomer of the content for reducing carboxylic monomer, and described carboxylic monomer exerts an influence the corrosion-prone corrodibility by adherend such as the ITO surface of obtained adhesive layer to transparent and electrically conductive film.Therefore, the monomer of hydroxyl can contribute to improve the cohesive force of adhesive layer, and contributes to reduce corrodibility.In adhesive layer of the present invention, the content of the monomer of the hydroxyl containing in adhesive composition is preferably 0.1~5 weight part with respect to (methyl) acrylate monomer 100 weight parts of main component.
For the multipolymer of the adhesive composition for adhesive layer of the present invention, (methyl) acrylate monomer with respect to 100 weight parts as main component, more than preferably containing at least one in more than one and (D) carboxylic copolymerization sex ethylene base monomer of 0.1~5 weight part and/or the copolymerization sex ethylene base monomer of hydroxyl in the nitrogenous vinyl monomer of (C) of 5~50 weight parts, more than more than at least one in (methyl) alkyl acrylate monomer that described (A) alkyl carbon atoms number that contains 70~95 weight parts as (methyl) acrylate monomer of main component is C1~C14 containing at least one in (methyl) acrylate monomer of aryl with (B) of 5~30 weight parts.
In addition, with respect to (methyl) acrylate monomer 100 weight parts as main component, preferably contain more than one carboxylic copolymerization sex ethylene base monomer 2.0 weight parts following and/or below more than one copolymerization sex ethylene base monomer 5.0 weight parts of hydroxyl.
To the polymerization process of multipolymer, there is no particular limitation, can use the suitable known polymerization process such as solution polymerization process, emulsion polymerization.The weight-average molecular weight of multipolymer is preferably 200,000~2,000,000.
Above-mentioned multipolymer is preferably acrylic polymers, preferably contains acrylic monomer 50~100 % by weight such as (methyl) acrylate monomer or (methyl) vinylformic acid, (methyl) acrylic amide.
In above-mentioned adhesive composition, by above-mentioned multipolymer being coordinated to linking agent, suitable any additive, can adjust the characteristics such as required physical properties.
As linking agent, for example, can enumerate biuret modified body or the isocyanurate-modified body of the diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, '-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene vulcabond; Polyisocyanate compounds with affixture of the polyvalent alcohol more than trivalent such as TriMethylolPropane(TMP) or glycerine etc.; Metal species inner complex; More than at least one in epoxy compounds etc.In addition, also can binding agent be cross-linked by photo-crosslinkings such as ultraviolet rays.
In the situation that making crosslinking copolymers with linking agent, preferred copolymer has can carry out with linking agent functional group's (can select hydroxyl or carboxyl etc. according to the kind of linking agent) of crosslinking reaction, and preferably contains the monomer at side chain with these functional groups.In addition, preferred binder composition contains 0.01~5 weight part (E) linking agent.In addition, the benchmark of weight part is identical to (D) with (A) in above-mentioned multipolymer.
As other any compositions, can coordinate aptly the known additives such as silane coupling agent, antioxidant, tensio-active agent, curing catalyst, softening agent, weighting agent, crosslinking catalyst, cross-linked inhibitor, curing inhibitors, processing aid, protective agent.These additives can use separately or also use two or more uses.
Adhesive layer of the present invention can be by being coated with after above-mentioned adhesive composition in base material or mold release film, adhesive composition is cross-linked and obtains.
Wish that the adhesive layer of fitting for the interlayer of optics is thin adhesive layer, the thickness of preferred above-mentioned adhesive layer is 1 μ m~20 μ m.And conventionally the cohesive force of adhesive layer and the thickness of adhesive layer are roughly proportional, but cohesive force when preferred thickness 5 μ m is 4.0(N/25mm) more than.In addition, when the thickness of adhesive layer is not in the situation of 5 μ m, " cohesive force when thickness 5 μ m " is (N/25mm) that the thickness of adhesive layer is designated as to T(μ m), the cohesive force of adhesive layer is designated as to F(N/25mm), and calculate by formula " (cohesive force when thickness 5 μ m)=5F/T ".
When in the situation for the interlayer laminating of optics etc. by adhesive layer of the present invention, in order to reduce the reflection of the light on the interface of adhesive layer and optics, wish that refringence is as far as possible little.Therefore, the specific refractory power of above-mentioned adhesive layer is preferably 1.47~1.50.
Adhesive film of the present invention can be prepared by forming adhesive layer of the present invention at the one side of base material or mold release film.
As be used to form adhesive layer base material film or protection adhesive surface mold release film (barrier film), can use the resin moldings such as polyester film etc.
For base material film, can be on the face contrary with being formed with adhesive layer one side of resin molding, implement the antifouling processing undertaken by releasing agent or coating-forming agent, the silicon dioxide microparticle etc. of silicone, fluorine class, the antistatic treatment that can implement the coating by static inhibitor or sneak into etc. carried out.
For stripping film, fitting on the face of a side with the adhesive surface of adhesive layer, implement the demoulding processing that releasing agent by silicone, fluorine class etc. carries out.
By the two sides at an adhesive layer fit respectively mold release film enforcement the face of demoulding processing, can form the formation of " mold release film/adhesive layer/mold release film ".In the case, by the mold release film of both sides is peeled off and exposed adhesive surface successively or simultaneously, thereby can with the optical member adherings such as blooming.As blooming, can enumerate light polarizing film, phase retardation film, antireflection film, anti-dazzle (antiglare) film, ultraviolet-absorbing film, infrared absorbing film, optical compensation films, brightness raising film etc.
Adhesive film of the present invention can be used for various bloomings for peripheral components take Polarizer as main liquid-crystal display, various bloomings for touch panel, for Electronic Paper in the laminating of various bloomings, the various bloomings of organic EL etc.
In addition, can be at least one side of these bloomings stacked above-mentioned adhesive layer and prepare the blooming with adhesive layer.Particularly, can enumerate the formations such as " blooming/adhesive layer/blooming ", " blooming/adhesive layer/mold release film ", " blooming/adhesive layer ", " blooming/adhesive layer/blooming/adhesive layer/blooming ", " blooming/adhesive layer/blooming/adhesive layer/mold release film ", " mold release film/adhesive layer/blooming/adhesive layer/mold release film ".
For example; as " blooming/adhesive layer/mold release film "; in the case of having the adhesive layer of being protected by mold release film; expose the adhesive layer as " blooming/adhesive layer " by peeling mold release film off; and fit with other blooming, can obtain by adhesive layer for interlayer laminating as the formation of " blooming/adhesive layer/blooming ".
Embodiment
Illustrate the present invention by embodiment below.
The preparation > of < acrylic copolymer
[embodiment 1]
Import nitrogen to having in the reaction unit of stirrer, thermometer, reflux exchanger and nitrogen ingress pipe, thereby be nitrogen by the air displacement in reactor.Afterwards, in reaction unit, add butyl acrylate 90 weight parts, phenoxyethyl acrylate 10 weight parts, diethyl acrylamide 10 weight parts, vinylformic acid 1.0 weight parts, vinylformic acid 4-hydroxyl butyl ester 1.0 weight parts and solvent (ethyl acetate) 60 weight parts.Afterwards, through within 2 hours, splashing into the Diisopropyl azodicarboxylate as polymerization starter of 0.1 weight part, at 65 ℃, make its reaction 6 hours, to have obtained weight-average molecular weight be 500,000, for the acrylic acid copolymer soln 1 of embodiment 1.Get a part for acrylic copolymer, as determination of acid value sample described later.
[embodiment 2~5 and comparative example 1~3]
Except having adjusted respectively the composition of each monomer described in (D-2) as (A) of table 1, (B), (C), (D-1), similarly operate with the above-mentioned acrylic acid copolymer soln 1 for embodiment 1, obtained the acrylic acid copolymer soln for embodiment 2~5 and comparative example 1~3.At this, though measurement result is not shown especially, the weight-average molecular weight of the multipolymer containing in the acrylic acid copolymer soln of embodiment 2~5 and comparative example 1~3 is in 200,000~2,000,000 scope.
The preparation > of < adhesive composition, adhesive layer and adhesive film
[embodiment 1]
As the acrylic acid copolymer soln 1 of the embodiment 1 of above-mentioned preparation in add the affixture of Coronate L-45(tolylene diisocyanate (TDI) compound) 0.1 weight part and aluminum chelate (praseodynium aluminium) 0.1 weight part be uniformly mixed, obtained the adhesive composition of embodiment 1.This adhesive composition is coated on the stripping film being made up of the polyethylene terephthalate that scribbles silicone resin (PET) film, then at 90 ℃, be dried and remove solvent.Afterwards, by implement the ageing treatment of 7 days under 23 ℃, the environment of 50%RH, obtained the adhesive film at the one side of stripping film with the embodiment 1 of adhesive layer, described adhesive layer is to make that adhesive composition is crosslinked to be formed.
[embodiment 2~5 and comparative example 1~3]
Except having adjusted respectively the composition of additive as described in (E) of table 1, similarly operate with the adhesive film of above-described embodiment 1, obtain the adhesive film of embodiment 2~5 and comparative example 1~3.
[table 1]
In table 1, the numeric representation in bracket is made as 100 weight parts with (A) group and the total weight of (B) organizing and obtains (C) group~(E) numerical value of the weight part of group.
In addition, the compound title corresponding with the abbreviation of the each composition using in table 1 is shown in Table 2.At this, Coronate(コ ロ ネ ー ト, registered trademark) L-45 be Nippon Polyurethane Industry Co., Ltd. trade name, the trade name that D-11ON is Mitsui Chemicals, Inc.TDI nail phenylene diisocyanate, XDI refers to xylylene vulcabond.
[table 2]
< test method and evaluation >
Peel stripping film (scribbling the PET film of silicone resin) off and expose adhesive layer from the adhesive film of embodiment 1~5 and comparative example 1~3, and adhesive layer is transferred on the one side of Polarizer (film).
The measuring method > of < cohesive force
Adhesive layer is transferred to the one side of the Polarizer (film) of thickness 180 μ m, thereby has obtained the adhesive film (with the blooming of adhesive layer) as sample.
With pressure roller, this adhesive film is fitted on the non-tin face of the soda-lime glass cleaning with acetone.Afterwards, under the condition of 50 ℃, 0.5MPa × 20 minute, carry out after pressure kettle processing, getting back to the environment of 23 ℃ × 50%RH, the stripping strength of the adhesive film by stretching test machine determination after 1 hour.Measure according to JIS Z0237 " adhesive tape, bonding sheet test method ", the stripping strength when speed using 300mm/min is peeled off to 180 ° of directions is as the cohesive force of the adhesive layer of adhesive film.
The test method > of < tack
Measure the adhesive layer of the adhesive film of the sample after cohesive force with Visual Confirmation, and the state coming off with the Polarizer from substrate layer (film), judge its tack.
Zero adhesive layer does not come off from substrate layer completely.
A part for △ adhesive layer separates and comes off from substrate layer.
× adhesive layer comes off and is attached on glass by adherend from substrate layer.
The test method > of < weather resistance
By the adhesive film square 10cm preparing by the method same with the mensuration of cohesive force, use the same method and be fitted on the non-tin face of soda-lime glass, thereby obtained sample.The environment that this sample is placed on to 60 ℃ × 90%RH, after lower 250 hours, is taken out to the environment of 23 ℃ × 50%RH, the state of the adhesive film with visual observation after 1 hour, thus judge weather resistance.
Zero adhesive film does not completely produce and peels off and foam.
A part for △ adhesive film has produced to be peeled off and foams.
The entirety of × adhesive film has produced to be peeled off and foams.
The measuring method > of < specific refractory power
The specific refractory power of the adhesive layer at measuring 23 ℃ with Abbe refractometer (manufacturers: ERMA, model: ER-2S).
Evaluation result has been shown in table 3.
[table 3]
In the adhesive film of embodiment 1~5, the cohesive force of the adhesive layer of thickness 5 μ m is that 4.0N/25mm is above, the specific refractory power of adhesive layer in 1.47~1.50 scope and tack and weather resistance also excellent., the adhesive film of embodiment 1~5 can meet necessary requirement and overcome problem.
Use the adhesive composition of embodiment 1, and to have prepared adhesive layer thickness by identical method be the adhesive film of 3 μ m, 5 μ m, 10 μ m, 15 μ m, 20 μ m, and measured the cohesive force of adhesive layer, the results are shown in table 4.The cohesive force of the adhesive layer of the known adhesive composition that has used embodiment 1 is roughly proportional with the thickness of adhesive layer as is well known.
[table 4]
Perhaps, the adhesive film of comparative example 1 is because do not contain nitrogenous monomer in adhesive composition, a little less than the cohesive force of the adhesive layer of its thickness 5 μ m.In addition, due to (methyl) acrylate monomer not containing containing aryl, the specific refractory power of adhesive layer is low.And tack and weather resistance are also poor.
Perhaps, the adhesive film of comparative example 2 is because the use level of the copolymerization sex ethylene base monomer that contains carboxyl in adhesive composition is too much, a little less than the cohesive force of the adhesive layer of thickness 5 μ m.In addition, due to (methyl) acrylate monomer not containing containing aryl, the specific refractory power of adhesive layer is low.And sticking power and weather resistance are also poor.
Perhaps, the adhesive film of comparative example 3 is because neither contain the copolymerization sex ethylene base monomer that carboxylic copolymerization sex ethylene base monomer does not contain hydroxyl yet in adhesive composition, a little less than the cohesive force of the adhesive layer of its thickness 5 μ m, and tack and weather resistance also poor.
So, the adhesive film of comparative example 1~3 can not meet necessary requirement and overcome problem in the past.