TW201903096A - Double-sided adhesive sheet, 3D liquid crystal panel and manufacturing method thereof capable of being peeled off without damaging the adherend - Google Patents

Abstract

The present invention provides a double-sided adhesive sheet comprising a transparent film substrate, a UV-curable first adhesive layer laminated on one side of the transparent film substrate, and a UV-curable second adhesive layer laminated on the other side of the transparent film substrate, wherein the first adhesive layer and the second adhesive layer contain urethane (meth)acrylate as a UV-curable prepolymer and a photopolymerization initiator; the content of the photopolymerization initiator is 0.5 part by mass or more based on 100 parts by mass of the urethane (meth)acrylate, the melt viscosity at 50 DEG C before UV curing of the first adhesive layer and the second adhesive layer is 1.0*10 <SP>5</SP> to 3.0*10 <SP>6</SP> poise individually, and the melt viscosity change rate from 50 DEG C to 100 DEG C is 75% to 95%.

Description

Double-sided adhesive sheet, 3D liquid crystal panel and manufacturing method thereof

The present invention relates to a double-sided adhesive sheet, a 3D liquid crystal panel, and a method of manufacturing the same.

At present, with the popularity of digital electronic devices, liquid crystal displays (LCDs) have become extremely popular display devices, and are used as liquid crystal televisions, PC (Personal Computer) displays, mobile phone terminals, portable game consoles, and computing. The display unit of various machines such as watches and clocks. In particular, in recent years, for example, a phase difference plate containing glass (hereinafter, simply referred to as "phase difference plate") is adhered to the LCD for the purpose of imparting a 3D function. Here, the LCD to which the phase difference plate is adhered has a case where it is recovered after use and only the LCD is reused. For example, it is required to peel the phase difference plate from the LCD and perform secondary processing on the LCD. At this time, the prior method is a method of peeling the phase difference plate from the LCD by cooling the entire LCD (in other words, cooling the adhesive). However, this method requires equipment for cooling, and the workability is not good. Further, since both the phase difference plate and the LCD have rigidity, there is a problem in that any of the phase difference plates is broken. That is, the previous adhesive sheet is difficult to adhere to the LCD and the phase difference plate, and is easily peeled off at normal temperature and the LCD is subjected to secondary processing.

In order to solve such a problem, an adhesive sheet which can be easily peeled off at room temperature and even if the adherend is as hard as glass is being studied. For example, Patent Document 1 proposes an adhesive material having a structure in which an internal peeling interface is sandwiched inside an adhesive layer. Patent Document 1 discloses that the adhesive material can have both the secondary workability and the reliability of the adhesion surface such as peeling or foaming. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5514817

[The problem that the invention wants to solve]

The adhesive described in Patent Document 1 includes two or more adhesives, and an internal peeling interface is provided inside the adhesive. However, the adhesive of this document is attached to various adherends without accompanying the desired chemical reaction (in other words, it is difficult to cause a change in the state of the adhesive), so that when the adhesive is attached to the phase difference plate or the LCD The followability of the unevenness on the surface of each adherend becomes insufficient, which causes display unevenness. On the other hand, in order to prevent display unevenness, it is also conceivable to reduce the melt viscosity of the adhesive, but in this case, the adhesive force becomes too strong and secondary processing becomes difficult. Further, when the melt viscosity is largely lowered, the following problems occur: the fluidity is too high and the cohesive force is insufficient, and the holding force and the adhesive force with various adherends are impaired, and in particular, it is impossible to ensure reliability in a high temperature environment. Sex.

In view of the above, an object of the present invention is to provide a secondary process for adhering an adherend without peeling off the adherend (for example, peeling off the adherend at normal temperature). A double-sided adhesive sheet having excellent reliability and fit, a 3D liquid crystal panel, and a method of manufacturing the same. [Technical means to solve the problem]

The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, have found that a double-sided adhesive sheet having a specific structure and physical properties can solve the above problems, and completed the present invention.

That is, the present invention is as follows. (1) A double-sided adhesive sheet comprising a transparent film substrate, a UV (Ultraviolet) curing type first adhesive layer laminated on one surface of the transparent film substrate, and a laminated layer on the transparent film base The UV-curable second adhesive layer on the other side of the material, the first adhesive layer and the second adhesive layer containing (meth)acrylic acid urethane as a UV-curable prepolymer, and photopolymerization The content of the photopolymerization initiator in the amount of 100 parts by mass of the (meth)acrylic acid urethane is 0.5 parts by mass or more, and the first adhesive and the second adhesive layer are each before UV curing. The melt viscosity at 50 ° C is 1.0 × 10 ⁵ to 3.0 × 10 ⁶ poise, and the melt viscosity change rate from 50 ° C to 100 ° C is 75 to 95%. (2) The double-sided adhesive sheet of (1), wherein the transparent film substrate is not subjected to release treatment. (3) The double-sided adhesive sheet according to (1) or (2), wherein each of the first adhesive layer and the second adhesive layer has a thickness of 10 to 75 μm. The double-sided adhesive sheet according to any one of (1) to (3), wherein the second adhesive layer further contains a UV-curable polyfunctional monomer. (5) The double-sided adhesive sheet according to (4), wherein the UV curable polyfunctional monomer is contained in an amount of 100 parts by mass based on the (meth)acrylic acid urethane in the second adhesive layer It is 15 to 60 parts by mass. (6) The double-sided adhesive sheet according to any one of (1) to (5), wherein the (meth)acrylic acid urethane has a weight average molecular weight of 10,000 to 120,000, and the above (meth)acrylic acid amine The double bond equivalent of the carbamate is from 1,000 to 5,000 g/eq. (7) The double-sided adhesive sheet according to any one of (1) to (6) wherein the photopolymerization initiator is a fluorenylphosphine oxide-based photopolymerization initiator. The double-sided adhesive sheet according to any one of (4) to (7), wherein the UV-curable polyfunctional monomer is a (meth)acrylic monomer having two or more functional groups. (9) A 3D liquid crystal panel comprising a patterned phase difference glass plate, a liquid crystal display, and a double side of any one of (1) to (8) which adheres the patterned phase difference glass plate to the liquid crystal display In the adhesive sheet, the first adhesive layer is disposed on the side of the patterned retardation glass plate, and the second adhesive layer is disposed on the liquid crystal display side. (10) The 3D liquid crystal panel according to (9), wherein the 180° peel strength between the first adhesive layer after UV curing and the patterned retardation glass plate is 400 mN/25 mm or more, after UV curing The 180° peel strength between the first adhesive layer and the transparent film substrate is 400 mN/25 mm or more. (11) The 3D liquid crystal panel according to (9) or (10), wherein the 180° peel strength between the second adhesive layer after UV curing and the transparent film substrate is 50 to 200 mN/25 mm, UV The 180° peel strength between the second adhesive layer after curing and the liquid crystal display is 400 mN/25 mm or more. (12) A method of manufacturing a 3D liquid crystal panel, which uses the double-sided adhesive sheet according to any one of (1) to (8), and which comprises the steps of: After the UV curing is performed, it is bonded between the patterned retardation glass plate and the liquid crystal display, and then UV-cured. [Effects of the Invention]

According to the present invention, it is possible to provide a method for peeling off an adherend (for example, peeling at a normal temperature without causing damage to the adherend), thereby achieving secondary processing of the adherend, and having excellent reliability. A double-sided adhesive sheet, a 3D liquid crystal panel and a method of manufacturing the same.

Hereinafter, the form for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail. The present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention.

[Double-sided adhesive sheet] The double-sided adhesive sheet of the present embodiment comprises a transparent film substrate, a UV-curable first adhesive layer laminated on one surface of the transparent film substrate, and a laminated layer on the transparent film base The UV-curable second adhesive layer on the other side of the material, the first adhesive layer and the second adhesive layer containing (meth)acrylic acid urethane as a UV-curable prepolymer, and photopolymerization The content of the photopolymerization initiator in the amount of 100 parts by mass of the (meth)acrylic acid urethane is 0.5 parts by mass or more, and the first adhesive and the second adhesive layer are each UV-cured. The melt viscosity at 50 ° C is 1.0 × 10 ⁵ to 3.0 × 10 ⁶ poise, and the melt viscosity change rate from 50 ° C to 100 ° C is 75 to 95%. By providing the above-described configuration, the double-sided adhesive sheet of the present embodiment can be peeled off without being damaged by the adherend, whereby secondary processing of the adherend can be achieved, and excellent reliability and adhesion can be achieved. The double-sided adhesive sheet of the present embodiment can be easily subjected to secondary processing by peeling off the LCD from the adherend at room temperature, for example, and can provide good reliability.

The double-sided adhesive sheet of the present embodiment has three or more layers including a transparent film substrate and two types of adhesive layers, and the first adhesive layer is formed on one area layer of the transparent film substrate, and the other adhesive layer is formed on the other surface layer. There is the above second adhesive layer.

[Transparent Film Substrate] The material constituting the transparent film substrate is not particularly limited, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, polyethylene, and polyurethane. Polypropylene, polycarbonate, triacetyl cellulose, polyvinyl alcohol, polystyrene, and the like. These materials may be used alone or in combination of two or more. Among the above materials, from the viewpoint of reliability and peelability, it is preferably one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene. More preferably, it is polyethylene terephthalate.

The thickness of the transparent film substrate is preferably from 10 to 100 μm, more preferably from 25 to 75 μm. When the thickness is 100 μm or less, for example, the image quality of the image is further improved, and the viewing angle of the 3D image is more sufficiently ensured, and the thickness is 10 μm or more, and the handleability tends to be further improved.

In the double-sided adhesive sheet of the present embodiment, since the first adhesive layer and the second adhesive layer are excellent in release property, the transparent film substrate has sufficient release property even if it is not subjected to release treatment. On the other hand, when the transparent film substrate is subjected to a release treatment, the release property is further superior to the case where the release treatment is not performed. The release treatment at this time includes a treatment using an alkyd type, a polyoxymethylene type, an unsaturated polyester type, a polyolefin type, a wax type, or the like.

[Adhesive Layer] The double-sided adhesive sheet of the present embodiment includes a first adhesive layer laminated on one surface of the transparent film substrate and a second adhesive layer laminated on the other surface. Each of the first adhesive layer and the second adhesive layer contains (meth)acrylic acid urethane (hereinafter also referred to as "(A) component)) as (A) UV curable prepolymer, and ( B) Photopolymerization initiator (hereinafter also referred to as "(B) component"). In view of further adjusting the peel strength of the interface between the second adhesive layer and the transparent film substrate to an appropriate range, the second adhesive layer is preferably in addition to the above components (A) and (B). Further, (C) a UV-curable polyfunctional monomer (hereinafter also referred to as "(C) component") is contained.

The first adhesive layer and the second adhesive layer contained in the double-sided adhesive sheet of the present embodiment have a melt viscosity at 50 ° C before UV curing of 1.0 × 10 ⁵ to 3.0 × 10 ⁶ poise, and UV hardening. The melt viscosity change rate from 50 ° C to 100 ° C is 75 to 95%. When the melt viscosity is in the above range, the followability to the unevenness of the surface of each of the adherends is improved at the time of bonding, and the adhesion is excellent. Moreover, since the rate of change in the melt viscosity from 50 ° C to 100 ° C is in the above range, it is possible to maintain the followability of the unevenness on the surface of various adherends after bonding, and to suppress uneven display when the LCD is lit and displayed. And, for example, when displaying a 3D image, it is possible to prevent a 3D deviation from occurring. Here, the "3D deviation" refers to a phenomenon in which the liquidity is excessively high when the alignment is performed by the autoclave treatment after performing the alignment of the 3D display of the patterned phase difference glass plate and the LCD. Offset, it becomes impossible to perform 3D display.

The melt viscosity change rate from 50 ° C to 100 ° C before the UV curing of the first and second adhesive layers is more preferably 80 to 90%. Here, the melt viscosity can be measured by the method described in the examples below, and the melt viscosity change rate is a value calculated by the following formula (1).

Melt viscosity change rate = (melt viscosity at 50 ° C - melt viscosity at 100 ° C) / (melt viscosity at 50 ° C) × 100 (1)

Further, the rate of change in melt viscosity can be adjusted, for example, by changing the molecular weight of (A) the UV-curable prepolymer and (C) the amount of the UV-curable polyfunctional monomer.

<(A) component> The (meth)acrylic acid urethane which is (A) UV hardening type prepolymer contains the urethane structure in the main chain, and contains (meth) in a side chain. Acrylic based prepolymer. The (meth)acrylic acid urethane is not particularly limited, and examples thereof include (meth)acrylic acid urethane having a polycarbonate skeleton and (meth)acrylic acid amine group having a polyether skeleton. An acid ester, a (meth)acrylic acid urethane having a polyester skeleton, and the like, wherein, in view of the fact that the hardened adhesive sheet is free from yellowing, a (meth)acrylic acid amine having a polycarbonate skeleton is preferred. Carbamate.

The (meth)acrylic acid urethane having a polycarbonate skeleton means a polycarbonate having a polycarbonate structure and a urethane structure in the main chain and having a (meth)acrylic group in the side chain. Things. The (meth)acrylic acid urethane having a polycarbonate skeleton can be obtained, for example, by reacting a polycarbonate diol, a diisocyanate and a carboxylic acid diol to shrink the (meth)acrylic acid. The glyceride is reacted.

The weight average molecular weight of the polycarbonate diol is preferably from 170 to 1,000, more preferably from 300 to 700, still more preferably from 400 to 600. When the weight average molecular weight of the polycarbonate diol is in the above range, there is a tendency to impart a film property required for secondary processing to the main chain of the urethane prepolymer.

The diisocyanate is not particularly limited, and examples thereof include 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), and 4,4'-diphenyl. Methane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, phenyldimethyl diisocyanate ( XDI), tetramethyl dimethyl diisocyanate (TMXDI), tolidine diisocyanate (TODI), aromatic isocyanate such as 1,5-naphthalene diisocyanate (NDI); hexamethylene isocyanate (HDI), three Aliphatic polyisocyanate such as methylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate methyl ester (NBDI); trans cyclohexane-1,4-diisocyanate, An alicyclic polyisocyanate such as isophorone diisocyanate (IPDI) or H6XDI (hydrogenated XDI) is preferred, and among them, hexamethylene diisocyanate is preferred from the viewpoint of optical properties (not easy to yellow).

The carboxylic acid diol is not particularly limited, and examples thereof include dimethylol butyric acid and dimethylolpropionic acid.

The (meth)acrylic acid urethane having a polyether skeleton means a prepolymer having a polyether structure and a urethane structure in a main chain and having a (meth)acrylic group in a side chain. The (meth)acrylic acid urethane having a polyester skeleton means a prepolymer having a polyester structure and a urethane structure in the main chain and having a (meth)acrylic group in the side chain. The prepolymers may be the same as the (meth)acrylic acid urethane having the above polycarbonate skeleton, except that a polyether diol or a polyester diol is used instead of the polycarbonate diol. obtain. In this case, the numerical range of the preferred weight average molecular weight of each of the polyether diol and the polyester diol is a numerical range of the preferred weight average molecular weight of the above polycarbonate diol.

The weight average molecular weight of the component (A) is preferably from 10,000 to 120,000, more preferably from 30,000 to 70,000, still more preferably from 40,000 to 60,000. When the weight average molecular weight of the component (A) is in the above range, film formability and hardenability are improved, and reliability (for example, long-term reliability) tends to be further improved. Here, the weight average molecular weight means a value measured by gel permeation chromatography (GPC) using standard polystyrene having an average molecular weight of from about 500 to about 1,000,000.

The double bond equivalent of the component (A) is preferably from 1,000 to 5,000 g/eq, more preferably from 1,500 to 2,500 g/eq, and still more preferably from 1,800 to 2,200 g/eq. When the double bond equivalent of the component (A) is in the above range, there is a tendency that the effect of curing shrinkage is small, reliability (for example, long-term reliability) is more excellent, and hardening is further facilitated, and secondary processing is further performed. It's easy. Here, the double bond equivalent means the mass of the solid component (g) by the carboxyl group-containing (meth) acrylate / the molar number of the compound having an oxirane ring and an ethylenically unsaturated bond (g/mol) ) Calculated value.

The glass transition temperature (Tg) of the component (A) is preferably -10 to 20 ° C, more preferably -5 to 15 ° C, still more preferably 0 to 10 ° C. When the glass transition temperature is within the above range, the balance between reliability (for example, long-term reliability) and secondary workability tends to be further improved. Here, the glass transition temperature means a value measured by dynamic viscoelasticity measurement (DMA).

<(B) component> The (B) photopolymerization initiator is not particularly limited, and examples thereof include a mercaptophosphine oxide photopolymerization initiator, a benzophenone photopolymerization initiator, and an intramolecular hydrogen abstraction type. Photopolymerization initiator and the like. These photopolymerization initiators may be used alone or in combination of two or more. Among these, a mercaptophosphine oxide-based photopolymerization initiator is preferred from the viewpoint of reactivity and uniformity of hardening. Specific examples of the fluorenylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzimidylphenylphosphine oxide and 2,2-dimethoxy-1,2-diphenyl. Ethane-1-one, methyl phenylglyoxylate, and the like. Among these, from the viewpoint of further improving the radical generating efficiency and further improving the deep curing property, 2,4,6-trimethylbenzimidylphenylphosphine oxide is preferred.

<(C) Component> The second adhesive layer of the present embodiment preferably contains (C) a UV curable polyfunctional monomer in addition to the components (A) and (B). In order to achieve secondary processing of the LCD, it is necessary to increase the viscoelasticity at normal temperature, and by further adding a UV-curable polyfunctional monomer to the UV-curable prepolymer, the hardening of the second adhesive layer can be further improved. The density is further increased to further improve the viscoelasticity at normal temperature.

The component (C) is not particularly limited as long as it is a monomer having two or more functional groups, and examples thereof include a (meth)acrylic monomer, wherein the crosslinking density is increased to improve secondary workability. From the viewpoint, a (meth)acrylic monomer having two or more functional groups is preferred.

Specific examples of the component (C) include 1,4-butanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, and glycerin as the monomer having two functional groups. (meth) acrylate, tricyclodecane dimethanol diacrylate, and as a monomer having three functional groups, trimethylolpropane triacrylate, trimethylol methane tri(meth)acrylate Trimethylolpropane propylene oxide modified tri(meth) acrylate, as a monomer having four functional groups, dipentaerythritol tetra (meth) acrylate, pentaerythritol ethylene oxide modified four ( Methyl) acrylate, pentaerythritol tetra(meth) acrylate, pentaerythritol ethylene oxide modified tetra (meth) acrylate, di-trimethylolpropane tetra (meth) acrylate, dipentaerythritol hexaacrylate Wait. Among these, a (meth)acrylic monomer having four or more functional groups is more preferable from the viewpoint of more excellent secondary workability, and further preferably dipentaerythritol hexaacrylic acid having six functional groups. ester.

The content of the component (B) contained in each layer of the first adhesive layer and the second adhesive layer is 0.5 parts by mass or more, preferably 1.0 part by mass or more, more preferably 1.0 part by mass or more, more preferably 100 parts by mass of the component (A). It is 1.5 parts by mass or more. When the content of the component (B) is 0.5 parts by mass or more, the curing reactivity is improved, and secondary workability and reliability (for example, long-term reliability) are improved. The upper limit of the content of the component (B) is not particularly limited. However, if it is too large, the optical properties tend to be lowered. Therefore, it is preferably 7.0 parts by mass or less.

The content of the component (C) contained in the second adhesive layer is preferably 15 to 60 parts by mass, more preferably 18 to 40 parts by mass, even more preferably 20 to 30 parts by mass per 100 parts by mass of the component (A). Share. When the content of the component (C) is 15 parts by mass or more, the secondary workability at room temperature tends to be further improved, and if it is 60 parts by mass or less, the adhesiveness is further improved, and reliability (for example, long-term reliability) Sex) a tendency to be more excellent. In addition, when the content of the component (C) is adjusted to the above range with respect to 100 parts by mass of the component (A), the melt viscosity of the resin composition constituting the second adhesive layer is maintained within a certain range, and thus It is not easy to produce the advantages of uneven fit or image disorder. In addition, the mass part of the above content means the mass part calculated by the solid content component.

<(D) decane coupling agent> The adhesive layer of the double-sided adhesive sheet of this embodiment may contain (D) a decane coupling agent other than the above-mentioned (A)- (C) component (it is also called " (D) Ingredients"). In particular, when the viscoelasticity of the second adhesive layer is high, the adhesion to the adherend tends to decrease, but in the case where the decane coupling agent is contained, the adhesion is maintained, in particular, the adhered body is glass. The reliability (for example, long-term reliability) in the case of a board is further increased.

The component (D) is not particularly limited, and for example, any of a decane coupling agent such as a monomeric decane coupling agent, an alkoxy oligomer decane coupling agent, or a polyfunctional decane coupling agent may be used. Among them, from the viewpoint of improving the adhesion in the case where the adherend is glass, and maintaining long-term reliability, a (meth)acrylic-based decane coupling agent is preferred, and 3-propenyloxy group is more preferred. Propyltrimethoxydecane.

The content of the component (D) to 100 parts by mass of the component (A) is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3.0 parts by mass, still more preferably 0.5 to 1.5 parts by mass. When the content of the component (D) is in the above range, the balance between the long-term reliability and the secondary workability tends to be further improved.

<Other components> In the adhesive layer of the present embodiment, various fillers such as cerium oxide, aluminum oxide, and hydrated alumina, antioxidants, ultraviolet absorbers, and light may be contained in addition to the above components (A) to (D). Stabilizers, antistatic agents, leveling agents, antifoaming agents, coloring pigments, organic solvents, and the like which are usually added to the adhesive.

The method for producing the double-sided adhesive sheet of the present embodiment is not particularly limited. For example, the resin composition constituting the first adhesive layer may be applied onto a transparent film substrate, dried, and then coated on the opposite side. The resin composition constituting the second adhesive layer was dried to obtain a double-sided adhesive sheet provided with an adhesive layer on both sides. In particular, it is preferred to apply a resin composition constituting the adhesive layer to a varnish using an organic solvent, apply it to a transparent film substrate, and dry it. The organic solvent which can be used at this time is not particularly limited, and examples thereof include toluene, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether, and dimethyl acetamide. These organic solvents may be used alone or in combination of two or more. Among these, methyl ethyl ketone is preferred from the viewpoint of solubility. Further, the content of the organic solvent in the varnish is preferably from 30 to 90 parts by mass, more preferably from 40 to 70 parts by mass, per 100 parts by mass of the component (A).

As a method of coating the resin composition on the transparent base film, a notch coater, a die coater, a gravure coater, or the like can be suitably used depending on the coating thickness. The drying of the resin composition can be carried out by an in-line dryer or the like, and the drying conditions at this time can be appropriately adjusted depending on the type and amount of each component.

The thickness of each of the first adhesive layer and the second adhesive layer is preferably from 10 to 75 μm, more preferably from 20 to 60 μm, still more preferably from 30 to 50 μm. Further, the thickness referred to herein means the thickness after drying. When the thickness is 10 μm or more, the adhesiveness is further improved, and the reliability (for example, long-term reliability) tends to be further improved. Specifically, the term "long-term reliability" includes a case where the adhesion between the LCD and the patterned phase difference glass plate is good, so that it is difficult to shift, and the observer can observe a good 3D image. On the other hand, when the thickness of the first and second adhesive layers is 75 μm or less, the distance between the LCD and the patterned retardation glass plate becomes appropriate, and an appropriate viewing angle can be ensured when the 3D image is observed.

In the double-sided adhesive sheet of the present embodiment, a protective film may be further provided on the outer side of each of the first adhesive layer and the second adhesive layer. The protective film is not particularly limited, and examples thereof include one or more selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. a film of resin. Among these, a film containing a polyethylene terephthalate resin is preferred from the viewpoint of reducing the production cost.

In the protective film, the release layer with the adhesive layer can also be subjected to release treatment. By performing the release treatment on the protective film, the protective film can be easily peeled off during use, and the handleability is improved. The release treatment is not particularly limited, and for example, it can be carried out by using a release agent such as a polyfluorene-based release agent, a fluorine-based release agent, a long-chain alkyl graft polymer release agent, or a plasma treatment. Surface treatment methods, etc.

[3D liquid crystal panel] The 3D liquid crystal panel of the present embodiment includes the double-sided adhesive sheet of the embodiment in which the patterned retardation glass plate and the liquid crystal display (LCD) are bonded together, and the first adhesive layer is disposed on the patterning layer. On the side of the retardation glass plate, the second adhesive layer is disposed on the liquid crystal display side.

The 3D liquid crystal panel of the present embodiment adheres the patterned retardation glass plate to the LCD by using the double-sided adhesive sheet, and the transparent film substrate and the second adhesive layer can be prevented from being damaged by the patterned retardation glass plate or the LCD. The interface is easily peeled off. Next, the LCD can be reused by peeling off the LCD from the second adhesive layer.

After the first adhesive layer is cured by UV, the storage modulus at normal temperature (25 ° C) is preferably 1.0 × 10 ⁵ to 1.0 × 10 ⁸ Pa, more preferably 5.0 × 10 ⁵ to 5.0 × 10 ⁷ Pa, and further Preferably, it is 1.0×10 ⁶ ~1.0×10 ⁷ Pa. When the storage modulus of the first adhesive layer is in the above range, the reliability tends to be further improved particularly in a high-temperature and high-humidity environment. After the UV curing of the second adhesive layer, the storage modulus at normal temperature (25 ° C) is preferably 1.0 × 10 ⁸ to 1.0 × 10 ¹⁰ Pa, more preferably 5.0 × 10 ⁸ to 5.0 × 10 ⁹ Pa, and further Good is 8.0×10 ⁸ ~2.0×10 ⁹ Pa. When the storage modulus of the second adhesive layer is 1.0 × 10 ⁸ or more, the adhesion to the transparent film substrate is further improved, and the secondary workability tends to be further improved. On the other hand, when the storage modulus of the second adhesive layer is 1.0 × 10 ¹⁰ Pa or less, the reliability in a high-temperature and high-humidity environment tends to be further improved.

The viscoelasticity of the adhesive layer can be measured by dynamic viscoelasticity measurement (DMA), and in detail, it can be measured by the method described in the examples to be described later.

Regarding the peel strength of the interface between the layers, from the viewpoint of the balance between the secondary workability and the reliability, the 180° peel strength between the first adhesive layer and the patterned retardation glass plate after UV curing is preferably 400 mN/25 mm or more, the peel strength between the first adhesive layer and the transparent film substrate after UV curing is 400 mN/25 mm or more (180° direction). On the other hand, it is preferred that the 180° peel strength between the second adhesive layer and the transparent film substrate after UV curing is 50 mN/25 mm or more and 200 mN/25 mm or less (180° direction), UV hardening. The peel strength between the second adhesive layer and the LCD is 400 mN/25 mm or more. The 180° peel strength was determined by the method described in the examples which will be described later.

The double-sided adhesive sheet of the present embodiment can be used not only for the use of a 3D liquid crystal panel, but also for all applications in which a display device such as an LCD or an organic EL (Electroluminescence) is subjected to secondary processing. Examples of such applications include touch sensor panels, digital signage, and the like.

[Manufacturing Method of 3D Liquid Crystal Panel] The method for producing a 3D liquid crystal panel of the present embodiment uses the double-sided adhesive sheet of the present embodiment, and includes the following steps: the double-sided adhesive sheet is not subjected to UV curing. After the state is bonded between the patterned phase difference glass plate and the liquid crystal display, UV curing is performed. As a specific example of this step, it is possible to obtain a method in which a double-sided adhesive sheet is bonded to a patterned phase difference glass plate, and thereafter, an LCD is attached, and UV is irradiated to UV-harden the double-sided adhesive sheet. The UV irradiation conditions are not particularly limited.

In addition, the physical properties and the like of the present embodiment can be measured in accordance with the methods shown in the following examples unless otherwise specified. [Examples]

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited to the examples.

The components and materials used in the examples and comparative examples are as follows. [Component (A): UV-curable prepolymer] The UV-curable prepolymers (a) to (h) were produced in accordance with the following Synthesis Examples 1 to 7 and Comparative Synthesis Example 1.

[(B) component: photopolymerization initiator] (1) Photopolymerization initiator (a) 2,4,6-trimethylbenzimidylphenylphosphine oxide manufactured by BASF, trade name "Irgacure TPO" , mercapto phosphine oxide photopolymerization initiator (2) photopolymerization initiator (b) 2,2-dimethoxy-1,2-diphenylethan-1-one BASF company, trade name " Irgacure 651", phenyl ketene photopolymerization initiator (3) photopolymerization initiator (c) phenyl glyoxylate methyl ester manufactured by BASF, trade name "Irgacure MBF", intramolecular hydrogen abstraction photopolymerization Primer

[(C) component: UV-curable polyfunctional monomer] (1) UV-curable polyfunctional monomer (a) Dipentaerythritol hexaacrylate manufactured by Daicel Allnex, product name "DPHA" (2) UV-curable polyfunctional monomer Monomer (b) Tricyclodecane dimethanol diacrylate manufactured by Daicel Allnex, under the product name "IRR214-K" (3) UV-curable polyfunctional monomer (c) Trimethylolpropane triacrylate Daicel Allnex Manufacturing, product name "TMPTA"

[Other Ingredients] Adhesive 3M Company, product name "Optically Clear Adhesive 8146"

The evaluation methods and measurement methods of the respective physical properties are as follows.

[Secondary processing property] (1) Sample preparation procedure The release PET film on the adhesive layer (A) side of the double-sided adhesive sheet was peeled off, and laminated to the patterned phase difference glass plate (0.7 t , 19吋), autoclave treatment. The lamination is carried out by roll lamination, with a laminating roll temperature of 25 to 40 ° C, a laminating roll line pressure of 1.0 to 2.0 kgf/cm, a laminating roll speed of 0.3 to 2.0 m/min, and an autoclave at a temperature of 60 ° C. The pressure was 0.6 MPa and the time was 10 minutes. Next, the release PET film on the side of the adhesive layer (B) was peeled off, bonded to the LCD by vacuum lamination, autoclaved again, and subjected to UV exposure, thereby obtaining a test sample. The vacuum lamination was carried out at a temperature of 25 to 50 ° C, a pressure of 0.01 to 0.05 MPa, a vacuuming time of 60 seconds, and a pressurization time of 30 seconds. The autoclave was carried out at a temperature of 60 ° C and a pressure of 0.6 MPa for 1 hour. The UV exposure was carried out using an ultrahigh pressure mercury lamp light source so that the cumulative light amount became 3000 mJ/cm ² . (2) Measurement method At a normal temperature, a doctor blade was inserted into the interface of an untreated PET (Polyethylene Terephthalate) film and an adhesive layer (B) to pry open the test sample, and the following contents were carried out. Evaluation. ◎: It is easy to perform secondary processing without causing damage to the adherend. ○: Secondary processing can be performed without damage to the adherend. ×: It is difficult to perform secondary processing due to damage of the adherend.

[Reliability] (1) Sample preparation procedure Test samples were prepared in the same order as the secondary workability. (2) Measurement method The test sample was placed in a humidifier in an upright state. The conditions were set to a temperature of 50 ° C, a humidity of 80%, and a time of 240 hours. Thereafter, it was allowed to stand at room temperature for 24 hours. The deviation, bulging or foaming of the glass bonding position when visually observing the presence or absence of the case when starting to be placed in the moist heat device was evaluated by the following. ○: The positional deviation, bulging, and foaming of the glass were not generated. ×: The positional shift, bulging, and foaming of the glass occurred.

[Fitability] (1) Sample preparation procedure A test sample was prepared in the same order as the secondary workability. (2) Measurement method The display for illuminating the test sample was evaluated by visual observation as follows. ○: The display image did not produce uneven bonding, 3D deviation (no ghosting occurred) ×: The display image produced uneven bonding and 3D deviation (ghosting occurred)

[Optical characteristics] (1) Sample preparation procedure The release PET film on the adhesive layer (A) side of the double-sided adhesive sheet was peeled off, and bonded to an optical glass (40 mm square) by vacuum lamination. The vacuum lamination was carried out at a temperature of 25 to 50 ° C, a pressure of 0.01 to 0.05 MPa, a vacuuming time of 60 seconds, and a pressurization time of 30 seconds. Next, the release PET film on the side of the adhesive layer (B) was peeled off, and bonded to an optical glass (40 mm square) under the same conditions as the vacuum lamination described above, and subjected to autoclave treatment and UV exposure. This obtained a test sample. The autoclave was carried out at a temperature of 60 ° C and a pressure of 0.6 MPa for 1 hour. The UV exposure was carried out using an ultrahigh pressure mercury lamp light source so that the cumulative light amount became 3000 mJ/cm ² . The yellow index (YI) of the test sample was measured using a spectrophotometer (U-4100 manufactured by Hitachi High-Technologies Corporation). The measurement conditions were C light source, transmission, and wavelength λ = 380 to 760 nm. ◎: YI value is less than 1.5 ○: YI value is 1.5 or more and less than 2 ×: YI value is 2 or more

[Melt Viscosity] (1) Sample preparation procedure The resin compositions (A) and (B) were respectively applied to both sides of a 25 μm release PET by drying to a thickness of 50 μm, and dried at 130 ° C. After 5 minutes, a 25 μm release PET was placed on the opposite side to make a double-sided adhesive sheet. The release sheet of the above-mentioned adhesive sheet was peeled off, and 20 double-sided adhesive sheets were bonded to each other to form an adhesive sheet having a thickness of 1.0 mm. At this time, the lamination is carried out by roll lamination at a laminating roll temperature of 25 to 40 ° C, a laminating roll line pressure of 1.0 to 2.0 kgf/cm, and a laminating roll speed of 0.3 to 2.0 m/min. (2) Measurement method The melt viscosity was measured using a dynamic viscoelasticity measuring apparatus (Rheosol-G3000 manufactured by UBM Co., Ltd.). The measurement conditions were carried out at a temperature increase rate of 5.0 ° C/min in a temperature range of 30 to 130 ° C, and the fundamental frequency was set to 1 Hz, the strain control was set to 0.12 deg, and the load control was set to 300 g. The melt viscosity at 50 ° C and 100 ° C was measured, and the melt viscosity change rate when the temperature was raised from 50 ° C to 100 ° C was calculated by setting the melt viscosity at 50 ° C to 100.

[Peel strength] (1) Sample preparation sequence (1-1) Peel strength between the adhesive layer A and the patterned phase difference glass plate The release PET film on the adhesive layer A side of the double-sided adhesive sheet was peeled off. The film was bonded to the patterned phase difference glass plate by lamination, and after autoclaving, it was cured by UV exposure. The lamination is carried out by roll lamination at a laminating roll temperature of 25 to 30 ° C, a laminating roll line pressure of 1.0 to 2.0 kgf/cm, and a laminating roll speed of 0.3 to 2.0 m/min. The autoclave is at a temperature of 60 ° C. The pressure was 0.6 MPa and the time was 1 hour. The UV exposure was carried out using an ultrahigh pressure mercury lamp light source so that the cumulative light amount became 3000 mJ/cm ² . (1-2) Peel strength between the adhesive layer A and the transparent film substrate The release PET film on the side of the adhesive layer A of the double-sided adhesive sheet is peeled off, and laminated by lamination to be easily adhered The treated PET (PETA4300 #100 manufactured by Toyobo Co., Ltd.) was subjected to autoclave treatment and then hardened by a UV exposure machine. The lamination is carried out by roll lamination at a laminating roll temperature of 25 to 30 ° C, a laminating roll line pressure of 1.0 to 2.0 kgf/cm, and a laminating roll speed of 0.3 to 2.0 m/min. The autoclave is at a temperature of 60 ° C. The pressure was 0.6 MPa and the time was 1 hour. The UV exposure was carried out using an ultrahigh pressure mercury lamp light source so that the cumulative light amount became 3000 mJ/cm ² . (1-3) Peeling strength between the adhesive layer B and the transparent film substrate The release PET film on the side of the adhesive layer B of the double-sided adhesive sheet is peeled off, and laminated by lamination to be easily adhered The treated PET (PETA4300 #100 manufactured by Toyobo Co., Ltd.) was subjected to autoclave treatment and then hardened by a UV exposure machine. The lamination is carried out by roll lamination at a laminating roll temperature of 25 to 30 ° C, a laminating roll line pressure of 1.0 to 2.0 kgf/cm, and a laminating roll speed of 0.3 to 2.0 m/min, and the autoclave is at a temperature of 60 ° C. The pressure was 0.6 MPa and the time was 1 hour. The UV exposure was carried out using an ultrahigh pressure mercury lamp light source so that the cumulative light amount became 3000 mJ/cm ² . (1-4) Peeling strength between the adhesive layer B and the LCD The release PET film on the side of the adhesive layer B of the double-sided adhesive sheet was peeled off, and laminated to the LCD panel by vacuum lamination, and the autoclave was carried out. After the treatment, it was hardened by a UV exposure machine. The vacuum lamination was carried out at a temperature of 25 to 50 ° C, a pressure of 0.01 to 0.05 MPa, a vacuuming time of 60 seconds, and a pressurization time of 30 seconds. The autoclave was carried out at a temperature of 60 ° C and a pressure of 0.6 MPa for 1 hour. The UV exposure was carried out using an ultrahigh pressure mercury lamp light source so that the cumulative light amount became 3000 mJ/cm ² .

(2) Measurement method (2-1) Peel strength between the adhesive layer A and the patterned phase difference glass plate The sample prepared in the above (1-1) was cut into a width of 25 mm, and the measurement was performed in a 180° direction. Peel strength when the sheet is adhered to the surface. At this time, the measurement was performed at a peeling speed of 300 m/min. (2-2) Peel strength between the adhesive layer A and the transparent film substrate The sample prepared in the above (1-2) was cut into a width of 25 mm, and peeling was measured when the double-sided adhesive sheet was peeled off in the 180° direction. strength. At this time, the measurement was performed at a peeling speed of 300 m/min. (2-3) Peel strength between the adhesive layer B and the transparent film substrate The sample prepared in the above (1-3) was cut into a width of 25 mm, and peeling was measured when the double-sided adhesive sheet was peeled off in the 180° direction. strength. At this time, the measurement was performed at a peeling speed of 300 m/min. (2-4) Peel strength between the adhesive layer B and the LCD The sample prepared in the above (1-4) was cut into a width of 25 mm, and the peel strength at the time of peeling the double-sided adhesive sheet in the 180° direction was measured. At this time, the measurement was performed at a peeling speed of 300 m/min.

(Synthesis Example 1) UV-curable prepolymer (a) In a four-necked flask equipped with a thermometer, a condenser, and a stirring device, hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name: HDI, referred to as: HDI) 33.4 parts by mass, 59.4 parts by mass of a polycarbonate diol having a weight average molecular weight of 400, 7.3 parts by mass of dimethylolbutanoic acid, 1 part by mass of an organic tin compound such as dibutyltin laurate as a catalyst, and organic 100 parts by mass of methyl ethyl ketone of the solvent was placed in a reaction vessel, and reacted at 70 ° C for 24 hours. In order to confirm the reaction state of the obtained composition, an IR (Infrared) measuring machine was used for the analysis. In the IR chart, it was confirmed that the NCO characteristic absorption (2270 cm ^-1 ) of the composition disappeared, and it was confirmed that the composition was a urethane urethane having a carboxyl group. Next, 100 parts by mass of the obtained urethane urethane having a carboxyl group, 7.1 parts by mass of glycidyl methacrylate, 0.7 parts by mass of triethylamine as a catalyst, and hydroquinone as a polymerization inhibitor. 0.05 parts of the polymer were placed in a reaction vessel, and the reaction was carried out at 75 ° C for 12 hours, whereby an addition reaction was carried out, whereby a UV-curable prepolymer (a) was obtained. Further, the addition reaction was terminated at a time point when the acid value measured by the following method became 5 mgKOH/g or less. Further, the obtained UV-curable prepolymer (a) had a weight average molecular weight of 50,000, a solid content concentration of 50% by mass, a double bond equivalent of 2,000 g/eq, and a Tg of 5 °C.

(Method for measuring acid value) 1 g of the solid content of the resin was weighed, and dissolved in a mixed solvent (mass ratio: toluene/methanol = 50/50), and then an appropriate amount of phenolphthalein solution was added as an indicator to utilize 0.1 N of hydrogen. The potassium hydroxide aqueous solution was titrated, and the acid value was measured by the following formula (α). x=10×Vf×56.1/(Wp×I) (α) (In the formula (α), x represents an acid value (mgKOH/g), and Vf represents a titration amount (mL) of a 0.1 N aqueous KOH solution, Wp Indicates the mass (g) of the resin solution measured, and I represents the ratio (% by mass) of the nonvolatile component in the measured resin solution)

(Synthesis Example 2) UV-curable prepolymer (b) The same method as in Synthesis Example 1 except that hexamethylene diisocyanate was reacted with a polycarbonate diol compound at 70 ° C for 18 hours. The reaction was carried out to obtain a UV-curable prepolymer (b). The obtained UV-curable prepolymer (b) had a weight average molecular weight of 10,000, a solid content concentration of 50% by mass, a double bond equivalent of 2,000 g/eq, and a Tg of 5 °C.

(Synthesis Example 3) UV-curable prepolymer (c) The same method as in Synthesis Example 1 except that hexamethylene diisocyanate was reacted with a polycarbonate diol compound at 70 ° C for 48 hours. The reaction was carried out to obtain a UV-curable prepolymer (c). The obtained UV-curable prepolymer (c) had a weight average molecular weight of 120,000, a solid content concentration of 50% by mass, a double bond equivalent of 2,000 g/eq, and a Tg of 5 °C.

(Synthesis Example 4) UV-curable prepolymer (d) A UV-curable prepolymer (d) was obtained by the same method as in Synthesis Example 1, except that a polyether diol was used instead of the polycarbonate diol. . The obtained UV-curable prepolymer (d) had a weight average molecular weight of 50,000, a solid content concentration of 50%, a double bond equivalent of 2,000 g/eq, and a Tg of 0 °C.

(Synthesis Example 5) UV-curable prepolymer (e) A UV-curable prepolymer (e) was obtained by the same method as in Synthesis Example 1, except that a polyester diol was used instead of the polycarbonate diol. . The obtained UV-curable prepolymer (b) had a weight average molecular weight of 50,000, a solid content concentration of 50%, a double bond equivalent of 2,000 g/eq, and a Tg of 0 °C.

(Synthesis Example 6) UV-curable prepolymer (f) The same method as in Synthesis Example 1 except that hexamethylene diisocyanate was reacted with a polycarbonate diol compound at 70 ° C for 12 hours. The reaction was carried out to obtain a UV-curable prepolymer (f). The obtained UV-curable prepolymer (f) had a weight average molecular weight of 5,000, a solid content concentration of 50% by mass, a double bond equivalent of 2,000 g/eq, and a Tg of 5 °C.

(Synthesis Example 7) UV-curable prepolymer (g) The same method as in Synthesis Example 1 except that hexamethylene diisocyanate was reacted with a polycarbonate diol compound at 70 ° C for 56 hours. The reaction was carried out to obtain a UV-curable prepolymer (g). The obtained UV-curable prepolymer (g) had a weight average molecular weight of 150,000, a solid content concentration of 50% by mass, a double bond equivalent of 2,000 g/eq, and a Tg of 5 °C.

(Comparative Synthesis Example 1) UV-curable prepolymer (h) In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen introduction tube, methoxypropanol propylene glycol monomethyl ether (PGM) was added as a polymerization solvent. 100.0 g was heated to 80 degrees while stirring under a nitrogen gas stream. 13.5 parts by mass of styrene previously mixed at room temperature, 67 parts by mass of ethyl acrylate, 11.5 parts by mass of acrylic acid, and 0.5 g of azobisisobutyronitrile as a radical polymerization initiator were kept at 80 ° C for a period of time. It was added dropwise to the dropping funnel over 3 hours. After the completion of the dropwise addition, the reaction solution was stirred while the temperature was raised to 90 ° C, and the temperature of the reaction solution was maintained at 90 degrees while stirring for further 2 hours to obtain a copolymer. Next, 100 parts by mass of the obtained copolymer, 7.8 parts by mass of glycidyl methacrylate, 0.8 parts by mass of triethylamine as a catalyst, and 0.05 part of hydroquinone as a polymerization inhibitor were placed in the reaction. The vessel was subjected to a reaction at 100 ° C for 12 hours, and an addition reaction was carried out, whereby a UV-curable prepolymer (h) was obtained. Further, the addition reaction is terminated at a time point when the acid value becomes 5 mgKOH/g or less. Further, the obtained UV-curable prepolymer (h) had a weight average molecular weight of 45,000, a solid content concentration of 47% by mass, and a Tg of 3 °C.

(Example 1) (1) Preparation of a UV-curable resin composition: 100 parts by mass of a UV-curable prepolymer (a) was added to a reaction container, and 0.5 part by mass of a photopolymerization initiator (a) was further added, and 140 parts by mass of methyl ethyl ketone of the solvent was stirred to obtain a resin composition (A). 100 parts by mass of the UV curable prepolymer (a) is added to the reaction vessel, and further 25 parts by mass of the UV curable polyfunctional monomer (a), 1.5 parts by mass of the photopolymerization initiator (a), and a solvent are added. 140 parts by mass of methyl ethyl ketone was stirred to obtain a resin composition (B). (2) Preparation of double-sided adhesive sheet The resin composition (A) obtained in the above (1) was applied to a 25 μm untreated PET film so as to have a thickness of 50 μm or more after drying, at 130 ° C. After drying for 5 minutes to form the adhesive layer (A), a 50 μm release PET film was placed on the opposite side to obtain a single-sided adhesive sheet. The resin composition (B) obtained in the above (1) was applied onto the untreated PET film of the above-mentioned single-sided adhesive sheet so as to have a thickness of 50 μm or more after drying, and dried at 130 ° C. After forming the adhesive layer (B) in minutes, a release film of 75 μm was placed to obtain a double-sided adhesive sheet. The obtained double-sided adhesive sheet was used for evaluation of secondary workability, reliability, fit, optical characteristics, melt viscosity, and peel strength.

(Examples 2 to 6) and (Comparative Examples 1 to 5)

In the fixed adhesive layer (B), the resin composition obtained by changing the type and content of each component as shown in Tables 1 and 2 was used to form the adhesive layer (A), and the same as in Example 1 except that The method obtained a double-sided adhesive sheet. The obtained adhesive sheet was used for evaluation of secondary workability, reliability, fit, optical characteristics, melt viscosity, and peel strength.

(Examples 7 to 20), (Comparative Examples 6 to 11) The adhesive layer (A) was fixed, and the resin composition obtained by changing the type and content of each component as described in Tables 3 to 5 was used to form an adhesive layer ( B), except that the double-sided adhesive sheet was obtained by the same method as in Example 1. The obtained adhesive sheet was used for evaluation of secondary workability, reliability, fit, optical characteristics, melt viscosity, and peel strength.

[Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

As shown in the above results, the double-sided adhesive sheet of the present embodiment can easily peel the LCD from the adherend at room temperature and perform secondary processing, and can provide good reliability and fit. [Industrial availability]

The double-sided adhesive sheet of the present invention has industrial applicability as an adhesive for liquid crystal display displays and the like.

Claims (12)

A double-sided adhesive sheet comprising a transparent film substrate, a UV-curable first adhesive layer laminated on one surface of the transparent film substrate, and a UV-curable layer laminated on the other surface of the transparent film substrate The second adhesive layer, the first adhesive layer and the second adhesive layer contain a (meth)acrylic acid urethane as a UV curable prepolymer, and a photopolymerization initiator, and the photopolymerization starts from The content of the starting agent relative to 100 parts by mass of the above (meth)acrylic acid urethane is 0.5 parts by mass or more, and the melt viscosity at 50 ° C of each of the first adhesive and the second adhesive layer before UV curing is 1.0 × 10 ⁵ ~ 3.0 × 10 ⁶ poise, and the melt viscosity change rate from 50 ° C to 100 ° C is 75 to 95%. The double-sided adhesive sheet of claim 1, wherein the transparent film substrate is not subjected to release treatment. The double-sided adhesive sheet according to claim 1 or 2, wherein each of the first adhesive layer and the second adhesive layer has a thickness of 10 to 75 μm. The double-sided adhesive sheet according to any one of claims 1 to 3, wherein the second adhesive layer further contains a UV-curable polyfunctional monomer. The double-sided adhesive sheet according to claim 4, wherein the content of the UV curable polyfunctional monomer relative to 100 parts by mass of the (meth)acrylic acid urethane in the second adhesive layer is 15~ 60 parts by mass. The double-sided adhesive sheet according to any one of claims 1 to 5, wherein the (meth)acrylic acid urethane has a weight average molecular weight of 10,000 to 120,000, and the above (meth)acrylic acid urethane The double bond equivalent is 1,000 to 5,000 g/eq. The double-sided adhesive sheet according to any one of claims 1 to 6, wherein the photopolymerization initiator is a fluorenylphosphine oxide-based photopolymerization initiator. The double-sided adhesive sheet according to any one of claims 4 to 7, wherein the UV-curable polyfunctional monomer is a (meth)acrylic monomer having two or more functional groups. A 3D liquid crystal panel comprising a patterned phase difference glass plate, a liquid crystal display, and a double-sided adhesive sheet according to any one of claims 1 to 8, wherein the patterned phase difference glass plate is bonded to the liquid crystal display. The first adhesive layer is disposed on the side of the patterned retardation glass plate, and the second adhesive layer is disposed on the liquid crystal display side. The 3D liquid crystal panel according to claim 9, wherein the 180° peel strength between the first adhesive layer after UV curing and the patterned retardation glass plate is 400 mN/25 mm or more, and the first 1 after UV curing The 180° peel strength between the adhesive layer and the above transparent film substrate is 400 mN/25 mm or more. The 3D liquid crystal panel according to claim 9 or 10, wherein the 180° peel strength between the second adhesive layer after UV curing and the transparent film substrate is 50 to 200 mN/25 mm, and the above after UV curing 2 The 180° peel strength between the adhesive layer and the above liquid crystal display is 400 mN/25 mm or more. A method of manufacturing a 3D liquid crystal panel, which uses the double-sided adhesive sheet according to any one of claims 1 to 8, and which comprises the steps of: drying the double-sided adhesive sheet without UV curing After bonding between the patterned phase difference glass plate and the liquid crystal display, UV curing is performed.