KR102031658B1 - Adhesive composition for optical use and adhesive film comprising the same - Google Patents

Abstract

The present invention relates to an optical pressure-sensitive adhesive composition and an adhesive film containing the same, and more particularly, a monofunctional urethane acrylate oligomer having a hydroxyl group (-OH), a monofunctional acrylate monomer, and three or more functional groups. By containing an isocyanate-based crosslinking agent and a free radical initiator, it is not only adhesive strength but also high crosslinking density, excellent cohesiveness, excellent durability such as heat and moisture resistance, etc. It relates to an adhesive composition and an adhesive film containing the same.

Description

Optical adhesive composition and adhesive film containing same {ADHESIVE COMPOSITION FOR OPTICAL USE AND ADHESIVE FILM COMPRISING THE SAME}

The present invention relates to an optical pressure-sensitive adhesive composition excellent in adhesive strength and cohesion and excellent pressure-sensitive adhesive film containing the same.

Recently, in the rapidly developing display industry, a touch panel or a touch screen is mounted, or an optically transparent pressure-sensitive adhesive is frequently used to obtain high brightness and high transparency.

A touch panel or a touch screen is a device that finds position coordinates by recognizing a change in potential generated by using a predetermined input means such as a pen or a finger. Specifically, when pressing any point of the upper substrate, the upper electrode formed of a transparent conductive film on the lower portion of the upper substrate and the lower electrode formed of a transparent conductive film on the lower substrate are in contact with each other to generate a potential difference, the change in the generated potential difference To be aware of.

Recently, the touch panel or the touch screen has been used as a device for inputting information in combination with a display device.

The pressure-sensitive adhesive used to attach the transparent conductive film of the touch screen or the touch panel can suppress the occurrence of curls or bubbles even when exposed to harsh conditions such as high temperature and high humidity conditions at the same time as adhesiveness to various substrates. Durability is required.

In general, acrylic or urethane acrylic pressure-sensitive adhesives are used to secure the visibility of the display, which requires a separate thickening process (thickness: 50 μm to 1000 mm).

The acrylate pressure sensitive adhesive has a problem that the curing process is too slow and the processability is low, and the urethane acrylate pressure sensitive adhesive has a problem that the curing process is fast during photopolymerization, but the physical properties such as adhesive strength are relatively lower than that of the acrylate oligomer.

Although a method of using a monofunctional urethane acrylate oligomer has been proposed [Korean Patent Laid-Open No. 2005-0021977], the urethane acrylate pressure sensitive adhesive has a problem that peeling failure occurs under heat conditions because the adhesive force is not high enough.

In addition, a method of using a bifunctional urethane acrylate oligomer has also been proposed (Korean Patent Laid-Open Publication No. 2005-0021977), but has a disadvantage in that surface tack is poor and cohesiveness is too high, so that adhesiveness is not easily expressed. .

The present invention is to provide an optical pressure-sensitive adhesive composition having high adhesion and cohesion, and excellent durability such as heat and moisture resistance.

In order to achieve the above object, the present invention is an optical containing a monofunctional urethane acrylate oligomer having a hydroxyl group (-OH), a monofunctional acrylate monomer, an isocyanate-based crosslinking agent having three or more functional groups and a free radical initiator It provides a pressure-sensitive adhesive composition.

The monofunctional urethane acrylate oligomer may include a main chain derived from a polyol having at least one molecular structure selected from the group consisting of polyethers, polyesters, polyolefins, polyacrylates, and polycarbonates.

Preferably, the monofunctional urethane acrylate oligomer may include a main chain derived from a polyol having a molecular structure of a polyolefin.

More preferably, the molecular structure of the polyolefin may be polyalkylene glycol.

The isocyanate-based crosslinking agent is an adduct in which 3 mol of the diisocyanate compound and 1 mol of the polyhydric alcohol compound are reacted; Isocyanurate body which self-condensed 3 mol of diisocyanate compounds; A burette body in which 1 mole of diisocyanate is condensed to diisocyanate urea obtained from 2 moles of 3 moles of diisocyanate compound; Triphenylmethanetriisocyanate; And it may be at least one selected from the group consisting of methylene bistriisocyanate.

Preferably the diisocyanate compound may be tolylene diisocyanate or xylene diisocyanate.

40 to 80% by weight of monofunctional urethane acrylate oligomer having a hydroxyl group (-OH) at the terminal, 5 to 55% by weight of monofunctional acrylate monomer, 0.1 to 5% by weight of isocyanate crosslinking agent having 3 or more functional groups and free It may contain 0.1 to 5% by weight of radical initiator.

In addition, the present invention provides a pressure-sensitive adhesive of the pressure-sensitive adhesive composition.

In addition, the present invention is a transparent substrate film; It provides an adhesive film comprising the pressure-sensitive adhesive formed on one surface of the transparent base film.

The pressure-sensitive adhesive may have a thickness of 25 to 1000㎛.

The pressure-sensitive adhesive composition of the present invention has the advantage of excellent adhesive strength as well as high crosslinking density and excellent durability such as heat and moisture resistant heat. The adhesive force is excellent not only for plastic materials but also for inorganic materials.

In addition, since the pressure-sensitive adhesive composition of the present invention does not contain a separate solvent, it is possible to manufacture a thick-film pressure-sensitive adhesive film.

The present invention relates to an optical pressure-sensitive adhesive composition excellent in adhesive strength and cohesion and excellent pressure-sensitive adhesive film containing the same.

Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive composition of the present invention contains a monofunctional urethane acrylate oligomer having a hydroxyl group (-OH), a monofunctional acrylate monomer, an isocyanate crosslinking agent having three or more functional groups, and a free radical initiator.

Monofunctional urethane acrylate oligomer having a hydroxyl group (-OH) at the end serves to maintain the viscoelasticity and storage modulus by giving the physical properties and flexibility of the pressure-sensitive adhesive.

The monofunctional urethane acrylate oligomer includes a main chain portion due to the molecular structure of the polyol, a urethane bond group produced by the reaction of the isocyanate with the polyol, and an acrylate monomer including the isocyanate to bind a reactive group of the acryloyl group at the terminal thereof. It is done by

The hydroxyl group (-OH) formed at the terminal may form a hydrogen bond between the urethane acrylate oligomers, and is bonded to an isocyanate-based crosslinking agent having three or more functional groups, thereby increasing the crosslinking density of the pressure-sensitive adhesive composition to increase cohesion. .

The main chain may be derived from a polyol having at least one molecular structure selected from the group consisting of polyethers, polyesters, polyolefins, polyacrylates and polycarbonates. In terms of price and ease of viscosity control, the polyol having a molecular structure of a polyolefin, preferably polyalkylene glycol, may be derived from a polyol having a polyester, a polyether, or a mixed structure thereof. It is good.

The monofunctional urethane acrylate oligomer according to the present invention can be produced by a known method for polymerizing a polyol and a diisocyanate compound. The polyol can be prepared by using an cyclic ether monomer such as oxirane such as ethylene oxide, propylene oxide or tetrahydrofuran, for example, to prepare an oligomer having an ether main chain. In addition, the use of cyclic esters such as ε-caprolactone or pivalolactone can produce oligomers having an ester backbone.

When the diisocyanate compound is reacted with the prepared polyol, a polyol structure having a urethane bond group can be obtained. The diisocyanate compound is 1,4-butylene diisocyanate, 1,6-hexamethylene diisocyanate, cyclopentylene-1,3-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate , Cyclohexene-1,4-diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-methylenebis (phenyl isocyanate), 2,2-diphenylpropane-4 , 4'- diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, xylene diisocyanate, 1,4-naphthylene diisocyanate, 1,5-naphthylene diisocyanate 4,4'-diphenyl diisocyanate And an aliphatic diisocyanate compound selected from the group consisting of azobenzene-4,4'-diisocyanate, m- or p-tetramethylxylene diisocyanate and 1-chlorobenzene-2,4-diisocyanate It is preferable.

The polyol and the diisocyanate are reacted in a single ratio, and it is preferable to use an equivalent polyol or more in order to leave a hydroxyl group at the terminal.

In addition, the urethane acrylate oligomer may be prepared by reacting 2-isocyanatoethyl (meth) acrylate having an isocyanate group to further connect the acryloyl group to the reactant. It is preferable to add isocyanatoalkyl acrylate corresponding to half of the excess hydroxyl group equivalent of the polyol added in excess in order to contain a hydroxyl group at one end and introduce an acrylic group only at the other end during the reaction.

In consideration of the tackiness and heat resistance of the pressure-sensitive adhesive, the monofunctional urethane acrylate oligomer may maintain a glass transition temperature (Tg) of -60 to 0 ° C, preferably -60 to -20 ° C. In addition, the weight average molecular weight is 1,000 to 40,000, preferably 1,000 to 35,000.

Such monofunctional urethane acrylate oligomer may contain 40 to 80% by weight, preferably 50 to 70% by weight. When the content is less than 40% by weight, the viscosity of the pressure-sensitive adhesive composition may be difficult to coat, and when it exceeds 80% by weight, it may be difficult to control the balance of the pressure-sensitive adhesive composition and optical properties.

The monofunctional acrylate monomer provides durability to the film including the pressure-sensitive adhesive composition and maintains viscoelasticity, and serves to improve the coatability of the composition by adjusting the viscosity.

Specifically, ethyl acrylate, methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, t-butyl acrylate, isobornyl acrylate, isobutyl acrylate, allyl methacrylate, 2-ethoxyethyl ( Meth) acrylate, isodecyl (meth) acrylate, 2-dodecylthioethyl methacrylate, octyl acrylate, isooctyl acrylate, 2-methoxyethyl acrylate, hydroxyethyl (meth) acrylate, hydrate Oxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, stearyl (meth) acrylate, tetraperfuryl (meth) acrylate, Group consisting of phenoxyethyl (meth) acrylate, octadecyl methacrylate, tetrahydrofuryl acrylate, acrylic acid, cyclohexyl acrylate and acryloyl morpholine The book selected one or more may be used.

Preferably, the glass transition temperature (Tg) is preferably 0 ° C. or higher, and specifically one selected from the group consisting of acrylomorpholine, acrylic acid, t-butyl acrylate, tetrahydrofurfuryl methacrylate, and cyclohexyl acrylate. It is better to use the above.

Such monofunctional acrylate monomer may contain 5 to 55% by weight, preferably 5 to 40% by weight. If the content is less than 5% by weight, it may be difficult to expect an increase in adhesion with the plastic material, and when the content exceeds 55% by weight, the hardening shrinkage may be severe or the prepared pressure-sensitive adhesive may become hard.

In addition, a bifunctional or higher polyfunctional acrylate monomer may be further included within the scope without departing from the object of the present invention. The polyfunctional acrylate monomer may be used in an appropriate amount in consideration of the target curing rate to play a role of controlling the curing rate.

Specific examples of the polyfunctional acrylate monomer include 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, and ethylene glycol di (Meth) acrylate, bisphenol A-ethylene glycol diacrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) Acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (Meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, di (acryloxyethyl) iso Cyanurate, allylated cyclohexyldi (meth) acrylate, dimethyloldicyclopentanediacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol modified trimethylolpropanediacryl Difunctional monomers such as acrylate and adamantane diacrylate; Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane Trifunctional monomers such as tri (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; Pentafunctional monomers such as propionic acid-modified dipentaerythritol penta (meth) acrylate; Hexafunctional monomers, such as dipentaerythritol hexa (meth) acrylate and caprolactone modified dipentaerythritol hexa (meth) acrylate, etc. can be used.

Such a polyfunctional acrylate monomer is preferably contained within 5% by weight in the pressure-sensitive adhesive composition.

Isocyanate-based crosslinking agents having three or more functional groups combine with the hydroxy group (-OH) group of the monofunctional urethane acrylate oligomer to induce crosslinking density to increase cohesion.

The isocyanate-based crosslinking agent is an adduct in which 3 mol of the diisocyanate compound and 1 mol of the polyhydric alcohol compound are reacted; Isocyanurate body which self-condensed 3 mol of diisocyanate compounds; A burette body in which 1 mole of diisocyanate is condensed to diisocyanate urea obtained from 2 moles of 3 moles of diisocyanate compound; Triphenylmethanetriisocyanate; And it may be at least one selected from the group consisting of methylene bistriisocyanate.

The diisocyanate compound is tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate and naphthalene It may be at least one selected from the group consisting of diisocyanate. It is preferable that they are tolylene diisocyanate or xylene diisocyanate.

In addition, the polyhydric alcohol compound may be used, such as trimethylolpropane.

The isocyanate crosslinking agent having three or more such functional groups may contain 0.1 to 5% by weight, preferably 0.2 to 1% by weight. If the content is less than 0.1% by weight, the effect of improving cohesion may be insignificant, and when the content exceeds 5% by weight, the cohesion may be reduced due to excessive crosslinking.

The free radical photoinitiator plays a role of sufficiently advancing the internal and surface hardening of the pressure-sensitive adhesive, and the type is not particularly limited as long as it is known in the art.

Specific examples of the free radical photoinitiator include 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-chronolo Cetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenylketone, 1-hydroxycyclohexylphenylketone, 2-methyl -1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzo Phenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t -Butyl anthra Paddy, 2-aminoanthraquinone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chlorothioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyldimethyl Ketal, diphenyl ketone benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, fluorene, triphenylamine, carbazole and the like. have. Moreover, as a commercially available product, brand names Darocur 1173, Igacure 184, Igacure 907 (Ciba company), etc. can also be used. These can be used individually or in combination of 2 or more types.

The free radical photoinitiator may be used in an appropriate range in consideration of the emission characteristics, the intensity, the content of each component, etc. of the light source, and preferably contains 0.1 to 5% by weight.

The adhesive composition of the present invention can be cured to form an adhesive. In addition, transparent substrate film; An adhesive film may be formed by including the adhesive formed on at least one surface of the transparent base film.

The pressure-sensitive adhesive may have a thickness of 25 to 1000㎛.

The transparent base film is not particularly limited to those excellent in transparency, mechanical strength, thermal stability, moisture shielding, isotropy, and the like.

The curing is used in the art, but is not particularly limited, photocuring using ultraviolet light is generally. Usually, the photocuring is followed by thermosetting of 1 to 10 days at room temperature or warming to prepare a fully cured pressure-sensitive adhesive.

In the polymerization using ultraviolet rays, the light source has a light emission distribution having a wavelength of 400 nm or less, preferably 150 to 400 nm, more preferably 200 to 380 nm. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, and a chemical lamp , Black light lamps, microwave excited mercury lamps and metal halide lamps.

The intensity of light irradiation can be appropriately adjusted according to the required physical properties of the pressure-sensitive adhesive, the amount of accumulated light useful for the activity of the free radical photoinitiator is preferably 10 to 5000mJ / ㎠, more preferably 200 to 2000mJ / ㎠. It is preferable to have an appropriate curing reaction time within the above range, and do not cause a decrease in cohesion, yellowing or deterioration of the support of the cured product produced by the heat radiated from the lamp and the exotherm during the polymerization reaction.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely to illustrate the present invention, and various changes and modifications within the scope and spirit of the present invention are apparent to those skilled in the art, It is natural that such variations and modifications fall within the scope of the appended claims.

Production Example : urethane Acrylate Oligomer

Production Example  One: Monofunctional  urethane Acrylate Oligomer (Containing a hydroxyl group at the end, A-1)

100 g of polypropylene glycol was added to a 2 L reactor equipped with a reflux condenser, a thermometer, and a stirrer, and the temperature of the solution was raised to 60 ° C., and 0.1 g of dibutyltin dilaurate (DBTDL) was added thereto. After confirming that all of the added DBTDL was dissolved, 7 g of isophorone diisocyanate was slowly added using a dropping funnel for 30 minutes, and reacted for 4 hours while maintaining the reactor temperature at 60 ° C. Thereafter, 1 g of 2-methacryloyloxyethyl isocyanate (MOI) was added thereto, and reacted for an additional 4 hours at the same temperature to prepare a monofunctional urethane acrylate oligomer having a hydroxyl group at the terminal.

The remaining NCO peak was not observed by IR analysis by taking a part of the reaction product, and when the part of the reaction product was taken and reacted with additional isophorodiisocyanate, the viscosity increased, so that the reaction product was monofunctional having a hydroxyl group at the terminal. It was confirmed that it was a urethane acrylate oligomer.

The monofunctional urethane acrylate oligomer had a weight average molecular weight of 33,000 and a glass transition temperature of -57 ° C.

Production Example  2: 2-functional  urethane Acrylate Oligomer (At the end Acrylic group  Containing, A-2)

The same procedure as in Preparation Example 1 was carried out except that 8 g of isophorone diisocyanate was used and 2 g of 2-hydroxyethyl acrylate (HEA) was used instead of 1 g of 2-methacryloyloxyethyl isocyanate (MOI). A bifunctional urethane acrylate oligomer having an acryl group was prepared.

The remaining NCO peak was not observed in the IR analysis by taking a portion of the reaction product, and when taking a portion of the reaction product and reacting with an additional isophorodiisocyanate, the viscosity did not increase, so that the reaction product had acryl groups at both ends. It was confirmed that it was a bifunctional urethane acrylate oligomer.

The monofunctional urethane acrylate oligomer had a weight average molecular weight of 31,000 and a glass transition temperature of -55 ° C.

Production Example  3: Monofunctional  urethane Acrylate Oligomer (Contains alkoxy group at the end, A-3)

1 g of 2-hydroxyethyl acrylate (HEA) and n-butanol 0.8 instead of 1 g of 2-methacryloyloxyethyl isocyanate (MOI), using 8 g of isophorone diisocyanate (MOI) The monofunctional urethane acrylate oligomer which has butoxy group at the terminal was prepared using g.

The remaining NCO peak was not observed in the IR analysis by taking a part of the reaction product, and when the part was taken and reacted with an additional isophorodiisocyanate, the viscosity increased. It was confirmed that it was a functional urethane acrylate oligomer.

The monofunctional urethane acrylate oligomer had a weight average molecular weight of 31,000 and a glass transition temperature of -57 ° C.

Production Example  4: Monofunctional  urethane Acrylate Oligomer (Hydroxy group at the end, A-4)

A monofunctional urethane acrylate oligomer having a hydroxyl group at the end was prepared in the same manner as in Preparation Example 1, but using 100 g of polyethylene-propylene copolymer glycol instead of 100 g of polypropylene glycol.

The monofunctional urethane acrylate oligomer had a weight average molecular weight of 35,000 and a glass transition temperature of -37 ° C.

Example  1-6 and Comparative example  1-6

(1) adhesive composition

As shown in Table 1 below, a pressure-sensitive adhesive composition was prepared by mixing a urethane acrylate oligomer, an acrylate monomer, an isocyanate-based crosslinking agent, and a free radical initiator.

division
(weight%) Urethane acrylate oligomer Acrylate
Monomer Crosslinking agent Free radical initiator A-1 A-2 A-3 A-4 B-1 B-2 B-3 B-4 C-1 C-2 C-3 C-4 Example 1 60 - - - 28 9.5 - - 0.5 - - - 2 Example 2 60 - - - 28 - 9.5 - 0.5 - - - 2 Example 3 60 - - - 28 9.5 - - - 0.5 - - 2 Example 4 - - - 60 28 9.5 - - 0.5 - - - 2 Example 5 45 - - - 43 9.5 - - 0.5 - - - 2 Example 6 75 - - - 13 9.5 - - 0.5 - - - 2 Comparative Example 1 60 - - - 28 10 - - - - - - 2 Comparative Example 2 - 60 - - 28 9.5 - - 0.5 - - - 2 Comparative Example 3 - - 60 - 28 9.5 - - 0.5 - - - 2 Comparative Example 4 60 - - - - - - 37.5 0.5 - - - 2 Comparative Example 5 60 - - - 28 9.5 - - - - 0.5 - 2 Comparative Example 6 60 - - - 28 9.5 - - - - - 0.5 2 B-1: isobornyl acrylate, Tg = 94 ° C
B-2: t-butyl acrylate, Tg = 41 ° C.
B-3: Acryloyl morpholine, Tg = 145 degreeC
B-4: hexanediol diacrylate
C-1: TDI-trimethylolpropane adduct (Nippon urethane company coronate-L)
C-2: HDI-trimer (Nippon urethane coronate-HXR)
C-3: tolylene diisocyanate
C-4: hexamethylene diisocyanate
Free radical initiator: Ciba, Darocur-1173

(2) Preparation of Adhesive Film

The pressure-sensitive adhesive composition prepared in (1) was applied on a transparent base film coated with a silicone release agent to have a thickness of 300 μm, and the same transparent base film was laminated thereon, followed by a speed of 4 m / min (600 mJ / cm 2) It was irradiated and completely cured to form an adhesive.

Test Example

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

1.Adhesion (N / 25 mm )

① glass Glass ) Adhesion

After peeling off the base film coated with a release agent laminated on the adhesive film, the PET base film was not laminated. The adhesive sheet was cut into a size of 25 mm × 250 mm using a super cutter, bonded to glass, fixed to an autograph, and then peeled by 180 ° PEEL at a speed of 300 m / min.

② Triacetylcellulose ( TAC Film adhesion

A triacetyl cellulose (TAC) film was attached to the glass using a double-sided tape to prepare a TAC film-attached glass. After peeling the base film coated with the release agent on the prepared adhesive film, it was laminated on the TAC film. The adhesive sheet was cut into a size of 25 mm × 250 mm using a super cutter, bonded to a TAC film-attached glass, fixed to an autograph, and peeled by 180 ° PEEL at a speed of 300 m / min.

③ Polyethylene terephthalate ( PET Film adhesion

PET film was attached to the glass using a double-sided tape to prepare a glass to which the PET film adhered. After peeling the base film coated with the release agent on the prepared adhesive film, it was laminated on the PET film. The adhesive sheet was cut into a size of 25 mm × 250 mm using a super cutter, bonded to a PET film-attached glass, and then fixed to an autograph, and then peeled by 180 ° PEEL at a speed of 300 m / min.

2. Heat resistance

After peeling, the base film coated with the release agent laminated on the adhesive film was laminated on the unreleased PET (38um Toray Advanced Materials, Inc.) film. The pressure-sensitive adhesive sheet was cut into A4 size using a super cutter, bonded to glass, and then treated in an autoclave for 20 minutes at 50 ° and 5 atm, and then left in an 80 ° heat oven for 100 hours.

<Evaluation Criteria>

(Double-circle): There is no defect, such as air bubble, after heat resistance evaluation.

○: After the heat resistance evaluation, less than 10 bubbles of less than 1 μm were generated on the outside.

(Triangle | delta): More than 10 bubbles of 1 micrometer or less generate | occur | produce in the outer side after heat resistance evaluation.

X: Bubbles and lifting are severe after heat resistance evaluation.

3. Moisture and Heat Resistance

After peeling off the base film coated with a release agent laminated on the adhesive film, it was laminated on the unreleased PET film. The pressure-sensitive adhesive sheet was cut into A4 size using a super cutter, bonded to glass, and then treated in an autoclave for 20 minutes at 50 ° and 5 atm, followed by 100 hours in a 60 °, 60 RH% moisture resistant oven.

<Evaluation Criteria>

(Double-circle): There is no defect, such as air bubble, after a heat-and-moisture evaluation.

(Circle): Less than 10 bubbles of less than 1um generate | occur | produce in the outer side after evaluating moisture-heat.

(Triangle | delta): More than 10 bubbles of 1 micrometer or less generate | occur | produce in the outer side after evaluation of heat-and-moisture heat.

X: The bubble and the generation | occurrence | production of a float are severe after heat-and-moisture evaluation.

division Adhesion (N / 25mm) Heat resistance Moisture and Heat Resistance Glass TAC PET Example 1 25.5 17.6 19.3 ◎ ◎ Example 2 27.3 16.9 18.6 ◎ ◎ Example 3 24.8 17.2 18.3 ◎ ◎ Example 4 23.1 15.3 17.7 ◎ ◎ Example 5 24.8 15.9 17.1 ◎ ◎ Example 6 23.1 14.7 16.7 ◎ ◎ Comparative Example 1 21.0 13.5 15.0 × △ Comparative Example 2 5.7 2.5 3.7 × × Comparative Example 3 18.3 10.2 13.7 △ × Comparative Example 4 1.6 1.7 1.2 × × Comparative Example 5 21.1 14.4 16.9 △ △ Comparative Example 6 20.7 13.6 15.2 ○ ×

As shown in Table 2, the optical pressure-sensitive adhesive composition of Examples 1 to 6 according to the present invention has excellent adhesion durability, such as moisture and heat resistance and heat resistance at the same time as the adhesive strength to glass, TAC and PET, compared to Comparative Examples 1 to 5 I could confirm that.

Claims (10)

A non-solvent type optical pressure-sensitive adhesive composition containing a monofunctional urethane acrylate oligomer having a hydroxyl group (-OH) at a terminal, a monofunctional acrylate monomer, an isocyanate crosslinking agent having three or more functional groups, and a free radical initiator, and a hydroxyl group at the terminal. The monofunctional urethane acrylate oligomer having (-OH) has a glass transition temperature of -60 to -20 ° C.
The method according to claim 1, wherein the monofunctional urethane acrylate oligomer comprises a main chain derived from a polyol having at least one molecular structure selected from the group consisting of polyethers, polyesters, polyolefins, polyacrylates and polycarbonates. A solvent-free optical pressure-sensitive adhesive composition.
The pressure-sensitive adhesive composition for a solvent-free optical type according to claim 2, wherein the monofunctional urethane acrylate oligomer comprises a main chain derived from a polyol having a molecular structure of polyolefin.
The solvent-free optical pressure-sensitive adhesive composition of claim 3, wherein the polyolefin has a molecular structure of polyalkylene glycol.
The method of claim 1, wherein the isocyanate-based crosslinking agent is an adduct in which 3 mol of the diisocyanate compound and 1 mol of the polyhydric alcohol compound; Isocyanurate body which self-condensed 3 mol of diisocyanate compounds; A burette body in which 1 mole of diisocyanate is condensed to diisocyanate urea obtained from 2 moles of 3 moles of diisocyanate compound; Triphenylmethanetriisocyanate; And at least one solvent-free optical pressure-sensitive adhesive composition selected from the group consisting of methylene bistriisocyanate.
The solvent-free optical pressure-sensitive adhesive composition of claim 5, wherein the diisocyanate compound is tolylene diisocyanate or xylene diisocyanate.
The isocyanate crosslinking agent according to claim 1, wherein 40 to 80% by weight of a monofunctional urethane acrylate oligomer having a hydroxy group (-OH) at the terminal, 5 to 55% by weight of a monofunctional acrylate monomer, and three or more functional groups A solvent-free optical pressure-sensitive adhesive composition containing 5% by weight and 0.1 to 5% by weight of free radical initiator.
The adhesive which hardened the adhesive composition of any one of Claims 1-7.
Transparent substrate film;
An adhesive film comprising the adhesive of claim 8 formed on one surface of the transparent substrate film.
The pressure-sensitive adhesive film of claim 9, wherein the pressure-sensitive adhesive has a thickness of 25 to 1000 μm.