KR20120138481A - Adhesive sheet for optical use and preparing method the same - Google Patents

Abstract

PURPOSE: An optical adhesive sheet for optics is provided to have excellent adhesion, heat resistance, and moisture resistance, and good reworkability, and to be easily re-separated during an attaching process. CONSTITUTION: An optical adhesive sheet for optics has a different separation to the glass of an upper side and a lower side of an adhesive layer. A manufacturing method of the optical adhesive sheet comprises: a step of spreading an adhesive composition on the top of a release film to have the thickness of a 25-1,000 micron after hardening; a step of photo-polymerizing by radiating a light of 10-5000 mJ/cm^2 to one surface of the top and bottom of the release film; and a step of varying the peeling force of the top and the bottom of the cured adhesive layer. [Reference numerals] (a) Peeling force A; (b) Peeling force B

Description

Optical adhesive sheet and manufacturing method thereof {ADHESIVE SHEET FOR OPTICAL USE AND PREPARING METHOD THE SAME}

The present invention relates to an optical adhesive sheet capable of easily re-peeling various image display device members and devices during a bonding process, as well as having excellent adhesion, heat resistance, heat and moisture resistance, and a reworking property, and a method of manufacturing the same.

Various image display devices including liquid crystal display devices (LCDs) are digital devices that transmit information of a specific content as well as various small devices such as mobile phones, portable game consoles, car navigation systems, digital cameras, small music or video players, and the like. As information display (DID), its use is expanding to advertisement, interior, electronic blackboard, three-dimensional image display, and the like.

As the use of the image display device is expanded, various functional materials such as a touch screen panel for inputting various information, a polymer film having good impact resistance to prevent the display panel from being damaged by an external environment such as weather change or shock, or It is required to be provided with a protective plate such as a glass plate.

The functional material or the protective plate is bonded onto the display panel using the adhesive sheet. The adhesive sheet is a thick film type adhesive, unlike a thin film type adhesive used for laminating various optical films including a polarizing plate, and is usually a solvent type or a solventless type containing an acrylate oligomer or a urethane acrylate oligomer between two release films. It is a structure in which the adhesive layer formed by photopolymerization hardening of an adhesive composition is interposed.

The pressure-sensitive adhesive (layer) must satisfy physical properties such as adhesion, reworkability, as well as adhesion, heat and moisture resistance. However, since the properties of the pressure-sensitive adhesives required for satisfying these physical properties are mutually conflicting, satisfying all of them is not completely solved. Thus, in the bonding process, expensive image display device members and devices such as display panels are discarded. Treatment causes problems of productivity loss and huge cost increase.

An object of the present invention is to provide an adhesive sheet for optics that is not only excellent in adhesiveness, heat resistance, and heat resistance and moisture resistance, but also has good rework property and is easily re-peeled during the bonding process.

Moreover, another object of this invention is to provide the manufacturing method of the said adhesive sheet for optics.

1. The adhesive sheet for optics from which the peeling force with respect to the glass of the upper surface and lower surface of an adhesive layer mutually differs.

2. In the above 1, the adhesive sheet for optics is a ratio of the peel force of the upper and lower glass to the glass of 1.35 or more.

3. In the above 1 or 2, any one of the peeling force on the glass of the upper surface and the lower surface is 10N / 25mm or more, the other is 5N / 25mm or more adhesive sheet for optics.

4. In the above 1, wherein the pressure-sensitive adhesive layer is formed by photopolymerization curing of the pressure-sensitive adhesive composition comprising 30 to 80% by weight monofunctional urethane acrylate oligomer, 10 to 60% by weight reactive diluent monomer and 0.1 to 10% by weight photopolymerization initiator Adhesive sheet for optics.

5. In the above 4, the monofunctional urethane acrylate oligomer is an optical pressure sensitive adhesive sheet having a weight average molecular weight of 5,000 to 50,000.

6. In the above 1, the thickness of the pressure-sensitive adhesive layer is 25 to 1,000㎛ optical adhesive sheet.

7. In the above 1, the optical pressure-sensitive adhesive sheet laminated on both sides of the pressure-sensitive adhesive layer.

8. coating the pressure-sensitive adhesive composition to the thickness of 25 to 1,000㎛ after curing on the upper surface of the release film; And irradiating light with an accumulated light amount of 10 to 5000 mJ / cm 2 in the direction of one of the upper and lower surfaces of the release film so as to cause the peeling force of the upper and lower surfaces of the cured pressure-sensitive adhesive layer to be different from each other. The manufacturing method of the adhesive sheet for optics which is done.

9. In the above 8, after the step of coating the pressure-sensitive adhesive composition, a method for manufacturing an optical pressure-sensitive adhesive sheet further comprising the step of laminating a release film on the coated pressure-sensitive adhesive composition.

10. The method of claim 8, further comprising the step of laminating a release film on the cured pressure-sensitive adhesive layer after the step of making the peeling force of the upper and lower surfaces different from each other.

Optical adhesive sheet according to the present invention is configured so that the peeling force on the glass of the upper and lower surfaces of the pressure-sensitive adhesive layer is different from each other, excellent adhesion, heat resistance and heat and moisture resistance, yet good reworking properties and high price including the display panel during the bonding process The member and apparatus for an image display device can be easily re-peeled. This can increase productivity and reduce costs.

1 is a cross-sectional view of the adhesive sheet for optics of the present invention,
It is sectional drawing for demonstrating the peeling force of the adhesive layer interposed in the optical adhesive sheet of this invention.

The present invention relates to an optical pressure-sensitive adhesive sheet and a method for manufacturing the same, which are excellent in adhesion, heat resistance, and moisture resistance, as well as good reworkability.

Hereinafter, the present invention will be described in detail.

The adhesive sheet for optics of this invention differs from each other in peeling force with respect to the glass of the upper surface and the lower surface of an adhesive layer.

More specifically, the pressure-sensitive adhesive layer is interposed between the two release films 11 and 12, and the peeling force A on the glass of the upper surface a and the peeling force B on the glass of the lower surface b are Different from each other.

The release films 11 and 12 are not particularly limited as long as they are excellent in transparency, mechanical strength, thermal stability, moisture shielding, isotropy, and the like. For example, polyester-based resins, such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene terephthalate; Cellulose-based resins such as diacetylcellulose and triacetylcellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, cycloolefin, or polyolefin having a norbornene structure, and an ethylene-propylene copolymer; Vinyl chloride resin; Amide resins such as nylon and aromatic polyamides; Imide resin; Polyether sulfone type resin; Sulfone resins; Polyether sulfone type resin; Polyether ether ketone resins; Sulfided polyphenylene resins; Vinyl alcohol type resin; Vinylidene chloride resins; Vinyl butyral resin; Allylate series resin; Polyoxymethylene type resin; Epoxy resin, and the like, and a film composed of the blend of the thermoplastic resin may also be used. Moreover, you may use the film which consists of thermosetting resins, such as a (meth) acrylic-type, a urethane type, an acryl urethane type, an epoxy type, a silicone type, or an ultraviolet curable resin. The release film may be one that is appropriately released by silicon-based, fluorine-based, silica powder, or the like.

The pressure-sensitive adhesive layer 20 may be formed by photopolymerization curing of the pressure-sensitive adhesive composition containing 30 to 80% by weight of the monofunctional urethane acrylate oligomer, 10 to 60% by weight of the reactive diluent monomer and 0.1 to 10% by weight of the photopolymerization initiator.

The monofunctional urethane acrylate oligomer is a component that maintains the viscoelasticity and storage modulus by providing physical properties and flexibility as an adhesive, and in the case of the polyfunctional urethane acrylate oligomer, the surface tacky is reduced and the cohesive force is excessively high, thereby increasing the adhesive properties. Monofunctional urethane acrylate oligomers are selected and used in view of their ease of expression.

The monofunctional urethane acrylate oligomer may be one obtained by generally reacting a (meth) acrylate monomer having a polyol, a diisocyanate compound and a hydroxy group. Specifically, a (meth) acrylic monomer having a hydroxy group and a urethane functional group generated by the reaction of the main chain portion, the polyol and the isocyanate compound due to the molecular structure of the polyol is bonded to produce an acryloyl functional group at the terminal.

The polyols include polyols, polyesters, polyolefins, polyacrylates, polycarbonates, polycaprolactones, or polyols having a mixed molecular structure thereof, and among these, in terms of ease of viscosity control and price Polyols, polyesters or polyols having a mixed molecular structure thereof are preferred. For example, when using a cyclic ether polyol such as ethylene oxide, propylene oxide or tetrahydrofuran, a urethane acrylate oligomer having an ether main chain can be prepared. In addition, when using a cyclic ester polyol such as ε-caprolactone or pivalolactone, an oligomer having an ester backbone can be prepared.

As the diisocyanate compound, 1,4-butylene diisocyanate, 1,6-hexamethylene diisocyanate, cyclopentylene-1,3-diisocyanate, 4,4'-dicyclohexyl methane diisocyanate, isophorone diisocyanate , Cyclohexene-1,4-diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-methylenebis (phenylisocyanate), 2,2-diphenylpropane-4,4 '-Diisocyanate, p-phenylenedi isocyanate, m-phenylene diisocyanate, xylene diisocyanate, 1,4-naphthylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenyl diisocyanate, azobenzene And aliphatic diisocyanate compounds such as -4,4'-diisocyanate, m- or p-tetramethylxylene diisocyanate, 1-chlorobenzene-2,4-diisocyanate, and these may be used alone or in combination of two or more. It can be mixed and used.

As an acrylic monomer which has a hydroxy group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate Hydroxyalkylene (2-4) glycol (meth) such as 6-hydroxyhexyl (meth) acrylate, 2 hydroxyethylene glycol (meth) acrylate and 2-hydroxypropylene glycol (meth) acrylate An acrylate etc. are mentioned, These can be used individually or in mixture of 2 or more types.

The manufacturing method of a monofunctional urethane acrylate oligomer is not specifically limited. For example, a polyol and a diisocyanate compound are reacted in excess in an appropriate equivalence ratio, preferably in order to improve the reaction efficiency, so as to obtain a prepolymer having a urethane group, and the (meth) acrylate monomer having a hydroxy group. By reacting in an appropriate equivalence ratio, a monofunctional urethane acrylate oligomer in which one end is formed with an acryloyl group and the other end is formed with an alcohol group can be prepared. At this time, an appropriate amount of alcohol (eg, butanol) can be added.

The monofunctional urethane acrylate oligomer preferably has a weight average molecular weight (Mw) of 3,000 to 50,000, more preferably 5,000 to 35,000. When the weight average molecular weight is less than 3,000, the durability may not be sufficient and problems such as bubbles or lifting may occur, and when the weight average molecular weight is more than 50,000, the viscosity may be increased and workability may be reduced.

The monofunctional urethane acrylate oligomer is preferably included in 30 to 80% by weight, more preferably 50 to 75% by weight in 100% by weight of the total pressure-sensitive adhesive composition. If the content is less than 30% by weight, the viscosity of the pressure-sensitive adhesive composition is low, the coating property is not good, if the content is more than 80% by weight the viscosity is increased, the processability may be lowered and it is difficult to satisfy the adhesive properties at the same time.

The reactive dilution monomer is a component that provides durability to the pressure-sensitive adhesive composition and maintains a storage modulus, and dilutes the solvent-free pressure-sensitive adhesive composition to control viscosity to facilitate coating.

The kind of reactive dilution monomer is not specifically limited, Usually, 1-6 functional monomers which can be hardened by photopolymerization are mentioned. Specifically, n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl ( Meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylic Latex, isooctyl (meth) acrylate, 2-methylbutyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, isoamyl (meth) acrylate, n-decyl (meth ) Acrylate, isodecyl (meth) acrylate, isobonyl (meth) acrylate, 4-methyl-2-pentyl (meth) acrylate, dodecyl (meth) acrylate, 2-dodecylthioethyl (meth) Acrylate, lauryl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methok Ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, allyl (meth) acrylate, stearyl (meth) acrylate, phenoxy Cethyl (meth) acrylate, tetraperfuryl (meth) acrylate, tetrahydrofuryl (meth) acrylate, acryloyl morpholine, (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, 3- ( Monofunctional monomers such as meta) acryloylpropionic acid; 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, 2-butyl-2-ethyl-1,3-propane Diol diacrylate, 1,9-nonanediol diacrylate, ethylene glycol di (meth) acrylate, bisphenol A-ethylene glycol diacrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) Acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylic Dicyclopentanyldi (meth) acrylate, caprolactone modified dicyclopentenyldi (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di ( Meta) acrylate , Di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, dimethyloldicyclopentanediacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neo Difunctional monomers such as pentyl glycol modified trimethylolpropanediacrylate and adamantanediacrylate; Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified trimethylolpropane tri (meth) acrylate, propylene oxide modified trimethylolpropane tree Trifunctional monomers such as (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, and glycerol tri (meth) acrylate; Tetrafunctional monomers such as diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and tetramethylolpropane tetra (meth) acrylate; Pentafunctional monomers such as dipentaerythritol penta (meth) acrylate and propionic acid-modified dipentaerythritol penta (meth) acrylate; Hexafunctional monomers, such as dipentaerythritol hexa (meth) acrylate and caprolactone modified dipentaerythritol hexa (meth) acrylate, etc. are mentioned. Among these, 2-ethylhexyl (meth) acrylate and isobonyl (meth) acrylate are preferable. These can be used individually or in mixture of 2 or more types.

The reactive diluent monomer may be included in 10 to 60% by weight in 100% by weight of the pressure-sensitive adhesive composition, preferably 20 to 50% by weight, more preferably 20 to 45% by weight. If the content is less than 10% by weight, the storage modulus may be too low and the curing may not be sufficient. If the content is more than 60% by weight, the coatability may not be good and curing shrinkage may occur.

A photoinitiator is a component for fully advancing hardening of the surface as well as the inside of the coated adhesive composition, If it is known in the art, the kind is not specifically limited. Specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, Dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chronolocetophenone, 4, 4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenylketone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4 -(Methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenyl Benzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-meth Tyl thioxanthone, 2-ethyl thioxanthone, 2-chloro thioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, diphenyl ketone benzyl dimethyl ketal, acetophenone Dimethyl ketal, p-dimethylaminobenzoic acid ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, fluorene, triphenylamine, carbazole and the like. Moreover, as a commercially available product, brand names Darocur 1173, Irgacure 184, Irgacure 907, Irgacure 1700, Irgacure OXE01 (Ciba company), etc. can also be used. These can be used individually or in combination of 2 or more types.

The photopolymerization initiator may be adjusted according to the content of other components included in the pressure-sensitive adhesive composition, and may be generally included in 0.1 to 10% by weight in 100% by weight of the total pressure-sensitive adhesive composition, preferably 0.1 to 5% by weight. If the content is less than 0.1% by weight, the curing speed may be slow and sufficient curing may be difficult to proceed, and when the content is more than 10% by weight, yellowing may occur, and haze occurs due to the presence of uninitiated photopolymerization initiator, resulting in decreased light transmittance. It may also be less durable.

In addition to the components as described above, the pressure-sensitive adhesive composition in order to adjust the adhesion, cohesion, viscosity, elastic modulus, glass transition temperature, color, antistatic properties, etc. required according to the application, adhesiveness-providing resin, silane coupling agent, antioxidant, corrosion Known additives such as inhibitors, leveling agents, surface lubricants, dyes, pigments, antifoams, fillers, light stabilizers, antistatic agents and the like may be further included.

The pressure-sensitive adhesive layer 20 is formed in the photopolymerization curing of the pressure-sensitive adhesive composition as described above, and in particular, in the present invention, the peeling force (A) on the glass of the upper surface (a) and the lower surface (b), which are two bonding surfaces of the pressure-sensitive adhesive layer 20, B) is different from each other.

It is preferable that the ratio of the peeling force with respect to the glass of the upper surface (a) and the lower surface (b) of the adhesive layer 20 is 1.35 or more, More preferably, it is 1.35-2. At this time, the ratio of peeling force shows the ratio of large peeling force / small peeling force. When the peeling force ratio is less than 1.35, cohesive failure of the pressure-sensitive adhesive layer may occur upon re-peeling during the bonding process, and thus the pressure-sensitive adhesive remains on the substrate bonded to both sides of the pressure-sensitive adhesive layer, resulting in poor workability.

While the pressure-sensitive adhesive layer 20 satisfies the above peeling force ratio, any one of the upper and lower peeling force on the glass, that is, the large peeling force is 10 N / 25 mm or more, and the other, that is, the small peeling force is 5 N / It is preferable that it is 25 mm or more. If the large peeling force is less than 10N / 25mm, the difference between the absolute value of the peeling force of the upper and lower surfaces is not so large that the effect of improving the workability is insignificant, and if the small peeling force is less than 5N / 25mm, the durability is not good. This can happen.

Although the thickness of the adhesive layer 20 is not specifically limited, It is good that it is 25-1,000 micrometers as a thick film type.

The optical adhesive sheet configured as described above has excellent adhesion, heat resistance, and heat resistance and moisture resistance, and has good rework property, so that an expensive image display device member and an apparatus including a display panel can be easily re-peeled during the bonding process. This increases productivity and reduces costs.

The optical adhesive sheet of the present invention is applicable to various image display apparatuses including liquid crystal displays, and is particularly useful when bonding various functional materials such as a touch panel or a protective plate onto a display panel. At this time, one of the upper and lower surfaces of the pressure-sensitive adhesive layer can be selected and bonded according to the substrate to be bonded. For example, when the protective plate and the display panel are bonded to each other, the surface of the adhesive layer having the smaller peeling force to the glass is bonded to the display panel, and the surface having the higher peeling force to the glass is bonded to the protective plate to configure the image display apparatus. Can be.

The present invention provides a method for producing the optical adhesive sheet.

Method for producing an optical pressure-sensitive adhesive sheet is a step of coating the pressure-sensitive adhesive composition to the thickness of 25 to 1,000㎛ after curing on the upper surface of the release film; And irradiating light with an accumulated light amount of 10 to 5000 mJ / cm 2 in the direction of one of the upper and lower surfaces of the release film so as to cause the peeling force of the upper and lower surfaces of the cured pressure-sensitive adhesive layer to be different from each other. Characterized in that.

According to one embodiment of the present invention, after the step of coating the pressure-sensitive adhesive composition may further comprise the step of laminating a release film on the coated pressure-sensitive adhesive composition.

In addition, according to another embodiment of the present invention, after the step of making the peel force of the upper and lower surfaces different from each other may further comprise the step of laminating a release film on the cured pressure-sensitive adhesive layer.

The method of coating the pressure-sensitive adhesive composition is not particularly limited, and for example, a method such as a bar coater, air knife, gravure, reverse roll, kiss roll, spray, blade, die coater, casting, spin coating, etc. is used on one release film. To coat the pressure-sensitive adhesive composition. At this time, the pressure-sensitive adhesive composition is coated so that the thickness becomes 25 to 1,000 µm after curing.

Although the hardening method is not specifically limited, Hardening using an ultraviolet-ray is mainly used. Light source having a luminescence distribution of 400 nm or less, preferably 150 to 400 nm, more preferably 200 to 380 nm when cured using ultraviolet light, such as low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, chemical lamp, black Light lamps, microwave excited mercury lamps, metal halide lamps and the like can be used.

Although the curing strength can be appropriately adjusted according to the required physical properties of the pressure-sensitive adhesive layer, the amount of accumulated light useful for the activity of the photopolymerization initiator is preferably 10 to 5000 mJ / cm 2, and more preferably 200 to 800 mJ / cm 2. Within the above range, it can be cured so that the peeling force on the glass of the upper surface and the lower surface of the pressure-sensitive adhesive layer is different from each other as desired in the present invention. In addition, it is preferable that the curing rate is easily controlled and does not cause a decrease in cohesion of the pressure-sensitive adhesive layer, yellowing or deterioration of the release film due to heat generated during heat or photopolymerization radiated from a lamp.

In the optical adhesive sheet manufactured by such a method, the peeling force (A) with respect to the glass of one direction to which light is irradiated, for example, the upper surface (a), is the glass of the bonding surface of the opposite direction, for example, the lower surface (b) It will have a value smaller than the peeling force (B). That is, the adhesive sheet which has a peeling force with respect to an asymmetric glass is manufactured.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but these examples are merely illustrative of the present invention and are not intended to limit the scope of the appended claims. It is apparent to those skilled in the art that various changes and modifications can be made to the present invention, and such modifications and changes belong to the appended claims.

Example

Example 1-10

To the pressure-sensitive adhesive composition was prepared in the component and content (% by weight) as shown in Table 1.

The prepared pressure-sensitive adhesive composition is coated onto a release film coated with a silicone release agent on one side of a polyethylene terephthalate (PET) film to have a thickness of 300 μm, and ultraviolet rays (600 mJ / cm 2) at a speed of 4 m / min in the upper direction of the release film. After irradiating and curing completely, the same release film was bonded to prepare an adhesive sheet.

Comparative Example 1

Example 1 was carried out in the same manner, but irradiated with ultraviolet (600mJ / ㎠) at a rate of 4m / min in both directions of the release film to prepare a pressure-sensitive adhesive sheet.

division Monofunctional urethane acrylate oligomer Reactive diluent monomer Photopolymerization Initiator Kinds content Kinds content Kinds content Example 1 A1 70 B1 28 C1 2 Example 2 A1 70 B1 / B2 25/3 C1 2 Example 3 A1 70 B3 28 C1 2 Example 4 A2 63 B1 35 C1 2 Example 5 A3 60 B3 38 C1 2 Example 6 A3 60 B4 38 C1 2 Example 7 A4 70 B1 28 C1 2 Example 8 A1 70 B5 28 C1 2 Example 9 A5 60 B1 38 C1 2 Example 10 A6 70 B1 / B6 20/8 C1 2 Comparative Example 1 A1 70 B1 28 C1 / C2 1/1 A1: DFCN-7, Negami chemistry (monofunctional, ether backbone, Mw 23,000)
A2: DFCN-13, negamine chemistry (monofunctional, carbonate backbone, Mw 18,500)
A3: DFCN-16, negamine chemistry (monofunctional, ether backbone, Mw 10,000)
A4: DFCN-5, Negami chemistry (monofunctional, ether backbone, Mw 31,000)
A5: KY-101, Negami Chemical (bifunctional, ester backbone, Mw 3,000)
A6: UN-9000PEP, Negami Chemical (monofunctional, with carbonate group, Mw 5,000)
B1: isobornyl acrylate
B2: trimethylolpropane triacrylate (M3160, Miwon)
B3: hydroxypropyl acrylate
B4: dipropylene glycol diacrylate
B5: trimethylolpropane triacrylate (M300, Miwon)
B6: acrylic acid
C1: photopolymerization initiator Darocur 1173 (Ciba)
C2: photopolymerization initiator Irgacure OXE01 (Ciba)

Test Example

The physical properties of the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 2 below.

One. Peel force N / 25mm)

After cutting from the adhesive sheet to the size of 25 mm x 250 mm using a super cutter, one release film was peeled off, it bonded to the glass plate, and the test piece was produced. The prepared specimen was fixed to a universal testing machine (UTM), and then peeled at 180 ° at a speed of 300 m / min to measure adhesive force.

2. heat resistant and Wet heat  durability

The pressure-sensitive adhesive sheet was cut into A4 size using a super cutter, one release film was peeled off, and then bonded to a glass plate, and then treated in an autoclave at 50 ° C. and 5 atmospheres for 20 minutes to prepare a specimen. The prepared specimens were then left to stand in an oven at 80 ° C. for 100 hours to measure heat resistance, and were left to stand at 60 ° C. for 60 hours in an oven at 60% RH to measure moisture resistance to heat resistance. After standing, the bonding surface of the glass plate and the adhesive layer of the test piece was visually observed and evaluated based on the following criteria.

<Evaluation Criteria>

(Circle): There is no bubble and peeling phenomenon in a joining surface.

(Triangle | delta): There exists a bubble or peeling phenomenon on the joining surface a little.

X: There are many lifting and peeling phenomenon in the joining surface.

3. Reworkability

The adhesive sheet was cut into the size of 25 mm x 250 mm using the super cutter, and the test piece was produced. Peel off one release film from the surface with high peeling force to the glass of the specimen made using the adhesive device (Ramipakka, Fujipura Co., Ltd.) and bond it to the unreleased PET film. The remaining one release film was peeled off from the small side and bonded to the glass plate to prepare a laminate. The prepared laminate was treated at 50 ° C., 5 kg / cm 2 (490.3 kPa) in an autoclave, and then stored in an oven at 50 ° C. for 48 hours. Then, the glass plate and the adhesive layer were peeled at 180 degrees at the speed | rate of 300 mm / min, and the surface of the glass plate after peeling was observed. The results were evaluated based on the following criteria.

<Evaluation Criteria>

(Circle): An adhesive does not remain on the glass plate surface.

(Triangle | delta): A small amount of adhesive exists in the glass plate surface.

X: There exist many peeling residues of an adhesive on the glass plate surface.

division Peel force against glass (N / 25 mm) durability Reworkability A B A / B Heat resistance Wet heat Example 1 20.1 12 1.68 ○ ○ ○ Example 2 11 8 1.38 ○ ○ ○ Example 3 18.3 12 1.53 ○ ○ ○ Example 4 19 12 1.58 ○ ○ ○ Example 5 19 12.7 1.50 ○ ○ ○ Example 6 17.1 11 1.55 ○ ○ ○ Example 7 20 15 1.33 ○ ○ △ Example 8 7 3.4 2.06 ○ △ ○ Example 9 4.8 2 2.40 ○ △ ○ Example 10 19.6 9 2.18 ○ ○ △ Comparative Example 1 4 4 One △ △ × A: Large peel force between upper and lower surfaces
B: Small peel force between upper and lower surfaces

As shown in Table 2, according to the present invention, the adhesive sheets of Examples 1 to 10 having the adhesive layers configured to have different peeling forces on the upper and lower surfaces of the glass from each other are not only excellent in adhesive force, heat resistance, and moisture resistance. It was found that the reworkability was good and re-peeling was easy. In particular, when the ratio of large peeling force and small peeling force is 1.35 to 2, it is more preferable in that all physical properties can be satisfied evenly.

11, 12: release film 20: pressure-sensitive adhesive layer
a: upper surface b: lower surface

Claims (10)

The adhesive sheet for optics which differs in peeling force with respect to the glass of the upper surface and the lower surface of an adhesive layer mutually.
The adhesive sheet for optics of Claim 1 whose ratio of the peeling force with respect to the glass of an upper surface and a lower surface is 1.35 or more.
The adhesive sheet for optics of Claim 1 or 2 in which peeling force with respect to the glass of an upper surface and a lower surface is 10 N / 25 mm or more, and the other is 5 N / 25 mm or more.
2. The optical of claim 1, wherein the pressure-sensitive adhesive layer is formed by photopolymerization curing of a pressure-sensitive adhesive composition comprising 30 to 80 wt% of monofunctional urethane acrylate oligomer, 10 to 60 wt% of reactive diluent monomer, and 0.1 to 10 wt% of photopolymerization initiator. Adhesive sheet for.
The adhesive sheet for optics according to claim 4, wherein the monofunctional urethane acrylate oligomer has a weight average molecular weight of 5,000 to 50,000.
The adhesive sheet for optics of Claim 1 whose thickness of an adhesive layer is 25-1,000 micrometers.
The adhesive sheet for optics of Claim 1 in which the release film was laminated | stacked on both surfaces of an adhesive layer.
Coating the pressure-sensitive adhesive composition on the upper surface of the release film to have a thickness of 25 to 1,000 μm after curing; And
And irradiating light with an accumulated light amount of 10 to 5000 mJ / cm 2 in the direction of one of the upper and lower surfaces of the release film to photopolymerize curing so that the peeling forces of the upper and lower surfaces of the cured pressure-sensitive adhesive layer are different from each other. The manufacturing method of the adhesive sheet for optics.
The method of manufacturing an adhesive sheet for optics according to claim 8, further comprising laminating a release film on the coated adhesive composition after the step of coating the adhesive composition.
The method of claim 8, further comprising laminating a release film on the cured pressure-sensitive adhesive layer after the peeling force of the upper and lower surfaces are different from each other.

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