JP2001311057A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet developing no unevenness of its own in liquid crystal display panel manufacturing process, giving high adhesion and enabling precision work to processed smoothly. SOLUTION: This adhesive sheet is so designed as to firmly and integratedly adhere to a translucent plastic film placed thereon and intended for a liquid crystal display panel and to a fixing base body placed on the underside thereof prior to ultraviolet irradiation, on the contrary, to decline in the adhesive force to the translucent plastic film only so as to enable the above film to be released easily from both the base body and the adhesive sheet after ultraviolet irradiation; wherein the adhesive sheet is composed of a base resin sheet, a UV-curable adhesive layer A formed on one side of the base resin sheet, and an adhesive layer B formed on the other side, and the adhesive layer A comprises 100 pts.wt. of an elastic polymer, 5-150 pts.wt. of an ultraviolet-crosslinkable resin, 1-100 pt(s).wt. of a tackifier, 0.1-20 pt(s).wt. of a polymerization initiator and 0.01-5 pt(s).wt. of a polymerization inhibitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive sheet used for producing a liquid crystal display panel.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal display panel,
Glass, resin sheets, and the like are used for substrates, but the amount of resin sheets used has been gradually increasing due to recent demands for lighter, thinner and smaller electronic devices.

[0003] When a liquid crystal display panel is manufactured using a resin sheet, a "material for a liquid crystal display" (Electronic Materials, February 1988, pp. 37-44) or an image of a liquid crystal which is difficult to see is used. Renewed Black and White STN Panel "(Nikkei Microdevices, October 1987, p. 78-
P. 98) was used. That is, a light-transmitting metal oxide electrode, an alignment film, and the like are formed directly on two resin sheets to form a laminate, rubbing treatment and the like are performed, and then spacers are sprayed. Performs processes such as superimposition of two laminates and sealing of the peripheral part with an adhesive, injection of liquid crystal and sealing of the injection port, lamination of deflection plates and color filters, and connection of IC chips and electrodes on a resin sheet. I was

However, when a high-precision, large-area liquid crystal display panel is manufactured on a flexible resin sheet, when electrodes are directly formed on the resin sheet as in the conventional case, the base is not provided. Since the material resin sheet is likely to bend, it is difficult to maintain a constant shape in a three-dimensional sense, so that it is not possible to perform processing with high precision like processing on a glass substrate, There has been a problem that it is difficult to secure the accuracy of alignment and to achieve automation.

[0005] Therefore, an extremely flat translucent plastic film is placed on a predetermined substrate and brought into close contact with the substrate, and various layers such as a translucent metal oxide electrode are formed on the translucent plastic film. The way was being taken. In this method, first, a light-transmitting metal oxide electrode is formed on a light-transmitting plastic film adhered to a substrate, and then an alignment film and the like are formed to form a first laminated substrate. And a spacer is placed on the alignment film. On the other hand, except that the spacers are not sprayed, a second laminated substrate is prepared in the same manner as the above method, a sealing agent layer or the like is formed therearound, and the second laminated substrate on which the sealing agent layer is formed is formed. Then, a liquid crystal display panel is manufactured by laminating and bonding a first laminated substrate, and injecting a liquid crystal and sealing an injection port.

The substrate used in the above process does not basically constitute a liquid crystal display panel, and must be removed by peeling off at any stage of the manufacturing process. Therefore, after laminating the second laminated substrate and the first laminated substrate and then bonding and removing the two substrates, or
The substrate is peeled off and removed from one of the laminated substrates in a process before bonding, and after laminating the second laminated substrate and the first laminated substrate, the other laminated substrate is peeled off and removed. Was taking the way.

In the manufacturing process of such a liquid crystal display panel, after a light-transmitting plastic film is brought into close contact with a substrate, a process of removing the substrate from the laminated substrate is performed.
A transparent plastic film must be firmly fixed on the substrate in order to smoothly carry out precise work.

If the translucent plastic film is weakly fixed to the substrate, the translucent plastic film may be wrinkled or broken, making precise work difficult. On the other hand, after the injection of the liquid crystal and the sealing of the injection port are performed, the substrate is not required. Therefore, it is necessary to easily peel the substrate from the translucent plastic film and the laminated substrate formed thereon. There is.

Therefore, when performing various operations on the light-transmitting plastic film, the adhesiveness to the light-transmitting plastic film is high. Thus, an adhesive sheet that can be easily peeled off is inserted between the translucent plastic film and the base to fix the adhesive sheet. However, even when such an adhesive sheet is used, unevenness occurs in the adhesive sheet at the interface between the light-transmitting plastic film and the adhesive sheet in the heating step for forming the alignment film, and thus the adhesive sheet is formed. There is a problem that the surface smoothness of the optical plastic is deteriorated.

[0010]

SUMMARY OF THE INVENTION In view of the above situation, the present invention has a high adhesiveness to a light-transmitting plastic even when heated, so that the adhesive sheet may be displaced, wrinkled or broken. Since there is no unevenness due to heating, the surface smoothness of the translucent plastic film can be kept good, and the adhesiveness that allows the precision work in the process of manufacturing the liquid crystal display panel to proceed smoothly. It is intended to provide a seat.

[0011]

SUMMARY OF THE INVENTION According to the present invention, prior to irradiation with ultraviolet light, a transparent plastic film for a liquid crystal display panel to be mounted thereon and a fixing substrate to be disposed thereunder are firmly bonded. On the other hand, after the ultraviolet irradiation, the adhesive force with only the light-transmitting plastic film is reduced so that the light-transmitting plastic film can be easily separated from the substrate and the adhesive sheet. An adhesive sheet configured, wherein the adhesive sheet is
A base resin sheet, a UV-curable pressure-sensitive adhesive layer A formed on one surface of the base resin sheet, and a pressure-sensitive adhesive layer B formed on another surface, the pressure-sensitive adhesive layer A, 100 parts by weight of an elastic polymer, 5 to 150 parts by weight of an ultraviolet crosslinkable resin, 1 to 100 parts by weight of a tackifier, 0.1 to 0.1 parts by weight of a polymerization initiator
An adhesive sheet comprising 20 parts by weight and 0.01 to 5 parts by weight of a polymerization inhibitor. Hereinafter, the present invention will be described in detail.

The adhesive sheet of the present invention comprises a base resin sheet and an adhesive layer A formed on one surface of the base resin sheet.
And a pressure-sensitive adhesive layer B formed on another surface, and before irradiation with ultraviolet light, a light-transmitting plastic film for a liquid crystal display panel mounted thereon and a fixing base disposed thereunder. After being irradiated with ultraviolet light, the adhesive strength with only the light-transmitting plastic film is reduced, and the light-transmitting plastic film can be easily separated from the substrate and the adhesive sheet of the present invention. It is an adhesive sheet configured to be peelable.

The base resin sheet is not particularly limited as long as it is a resin sheet capable of transmitting ultraviolet rays. Examples thereof include vinyl chloride resin, vinyl chloride / vinylidene chloride copolymer resin, and vinyl chloride / vinyl acetate copolymer. Examples of the resin sheet include resin, polyvinylidene chloride resin, polyolefin, polyvinyl alcohol, polyamide, polyester, polycarbonate, acetylcellulose, polyethylene terephthalate, and polyether sulfone.

An adhesive layer A is formed on one surface of the base resin sheet. The pressure-sensitive adhesive layer A is UV-curable, 100 parts by weight of an elastic polymer, and a UV-crosslinkable resin 5 to 5.
It comprises 150 parts by weight, 1 to 100 parts by weight of a tackifier, 0.1 to 20 parts by weight of a polymerization initiator, and 0.01 to 5 parts by weight of a polymerization inhibitor.

Examples of the elastic polymer include an acrylic resin-based pressure-sensitive adhesive and a saturated polyester resin. Above all, in the adhesive sheet of the present invention, an acrylic resin-based pressure-sensitive adhesive is preferable as the elastic polymer. Examples of the acrylic resin-based pressure-sensitive adhesive include a copolymer of an acrylate monomer and another copolymerizable monomer. The copolymer of the acrylate monomer and another copolymerizable monomer is mainly composed of the acrylate monomer capable of forming a polymer having a low glass transition point in order to impart tackiness. A monomer capable of forming a hard polymer having a high glass transition point in order to impart cohesiveness, as the other copolymerizable monomer described above, It can be obtained by using a monomer having a functional group such as a carboxylic acid group, an amide group, a glycidyl group, and a hydroxyl group for improvement.

The acrylate monomer is not particularly limited, and examples thereof include alkyl acrylates such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. These may be used alone or in combination of two or more.

Examples of the monomer capable of forming a hard polymer having a high glass transition point include vinyl acetate, acrylonitrile, styrene, methyl acrylate, methyl methacrylate and the like. These may be used alone or in combination of two or more.

Examples of the monomer having a functional group such as a carboxylic acid group, an amide group, a glycidyl group and a hydroxyl group include acrylic acid, methacrylic acid, itaconic acid and the like.
Examples thereof include hydroxylethyl methacrylate, hydroxylpropyl methacrylate, acrylamide, glycidyl methacrylate and the like. These may be used alone or in combination of two or more.

Examples of the UV-crosslinkable resin include, for example,
Acrylic esters or methacrylic esters which are oligomers or monomers that are cross-linked by irradiation with ultraviolet light in a specific wavelength range can be given, and these preferably have at least two acryloyl groups or methacryloyl groups in the molecule. .

Examples of the oligomer include oligoester acrylate. Examples of the monomer include an ester of acrylic acid with a polyhydric alcohol such as 1,6-hexanediol acrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, and dipentaerythritol hexaacrylate; 1,6-hexanediol Esters of polyhydric alcohols such as diacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dipentaerythritol hexaacrylate and methacrylic acid; urethane acrylate; epoxy acrylate and the like. These may be used alone or in combination of two or more.

When preparing the pressure-sensitive adhesive layer A, 5-150 parts by weight of the ultraviolet-crosslinkable resin is mixed with 100 parts by weight of the elastic polymer. If the blending amount of the UV-crosslinkable resin is less than 5 parts by weight, the adhesive force of the pressure-sensitive adhesive layer A does not substantially change before and after irradiation with ultraviolet light, whereas if it exceeds 150 parts by weight, the pressure-sensitive adhesive layer A after irradiation with ultraviolet light However, when the light-transmitting plastic film is separated from the pressure-sensitive adhesive layer A, the pressure-sensitive adhesive remains on the light-transmitting plastic film. Preferably, the compounding amount of the ultraviolet crosslinking resin is 10 to 10 parts by weight based on 100 parts by weight of the elastic polymer.
0 parts by weight. In addition, a weight part shows the ratio of the weight of a solid content.

The tackifier is not particularly limited.
Conventionally used adhesives can be used, for example, xylene resin; rosin; modified rosin resin such as polymerized rosin, hydrogenated rosin, rosin ester; terpene resin, terpene phenol resin, rosin phenol resin Terpene resins such as aliphatic, aromatic and alicyclic petroleum resins; coumarone resins; styrene resins; alkylphenol resins.
These may be used alone or in combination of two or more.

The amount of the tackifier is 1 to 100 parts by weight based on 100 parts by weight of the elastic polymer. If the amount of the tackifier is less than 1 part by weight, the adhesive strength of the pressure-sensitive adhesive layer A will be insufficient. When the compounding amount of the tackifier exceeds 100 parts by weight, the adhesive layer A remains on the translucent plastic film when the translucent plastic film is peeled off from the adhesive layer A. Preferably, the compounding amount of the tackifier is 5 to 50 parts by weight based on 100 parts by weight of the elastic polymer.

The above-mentioned polymerization initiator is used for accelerating the crosslinking of the above-mentioned ultraviolet-crosslinkable resin by irradiation with ultraviolet rays.
In the adhesive sheet of the present invention, conventionally known polymerization initiators can be used as the polymerization initiator, and examples thereof include benzoin alkyl ethers such as benzoin methyl ether and benzoin propyl ether; and aromatic compounds such as benzoin, benzyl and benzophenone. Oxyketones and aromatic ketones; benzyldimethyl ketal; polyvinylbenzophenone, and the like. These may be used alone or in combination of two or more.

The amount of the polymerization initiator is 0.1 to 20 parts by weight based on 100 parts by weight of the elastic polymer. If the amount of the polymerization initiator is less than 0.1 parts by weight, the crosslinking of the ultraviolet-crosslinkable resin does not progress even when irradiated with ultraviolet rays, so that the degree of decrease in the adhesive strength of the pressure-sensitive adhesive layer A is small, and
Even if the amount exceeds the weight part, the effect as a polymerization initiator does not change so much and it is not economical, so that it is limited to the above range. Preferably, the compounding amount of the polymerization initiator is the same as that of the elastic polymer 10
It is 0.5 to 10 parts by weight with respect to 0 parts by weight.

The polymerization inhibitor is used to prevent the ultraviolet-crosslinkable resin from being polymerized by factors other than ultraviolet irradiation, for example, heating. The addition of the polymerization inhibitor makes it difficult for the pressure-sensitive adhesive layer A to be polymerized even in a high-temperature working step, so that the surface of the pressure-sensitive adhesive layer A is unlikely to have irregularities, and the adhesive sheet and the light-transmitting plastic film The flatness of the interface with the substrate is maintained. As a result, the adhesiveness between the adhesive sheet and the light-transmitting plastic film does not decrease, and the surface smoothness of the light-transmitting plastic film can be kept good. The polymerization inhibitor is not particularly limited, and a conventionally known polymerization inhibitor can be used, and examples thereof include picric acid, phenol, hydroquinone, and hydroquinone monomethyl ether. These may be used alone or in combination of two or more.

The compounding amount of the polymerization inhibitor is 0.01 to 5 parts by weight based on 100 parts by weight of the elastic polymer.
If the amount is less than 0.01 part by weight, polymerization may be caused by factors other than irradiation with ultraviolet rays such as heating. If the amount exceeds 5 parts by weight, no further improvement in the effect of preventing polymerization is observed. Preferably, the compounding amount of the polymerization inhibitor is the above-mentioned elastic polymer 10
It is 0.05 to 2 parts by weight with respect to 0 parts by weight.

A surface of the light-transmitting plastic film which is in contact with the adhesive sheet is usually provided with a chemical-resistant layer for imparting solvent resistance. As the chemical resistant layer, an inorganic compound or an organic compound is surface-coated to protect the gas barrier layer. As the inorganic compound, for example, alumina, silicon oxide and the like are used.
As the organic compound, for example, an acrylic polymer, a polyamide polymer, or the like is used. When the adhesive sheet of the present invention is applied to a translucent plastic film in which an inorganic compound is not blended in the chemical resistant layer, the pressure-sensitive adhesive layer A of the adhesive sheet of the present invention further contains a silicone resin. Is preferred. In this case, if the silicone resin is not blended, the decrease in the adhesive strength after the heating step becomes insufficient.

The silicone resin is not particularly limited, and includes, for example, a silicone resin having a highly three-dimensionally crosslinked network structure, a silicone resin having a structure in which a plurality of OH groups and methyl groups are bonded to Si atoms, and the like. be able to. These silicone resins are preferably added as fine powder when preparing the pressure-sensitive adhesive layer. Of these, silicone resin powders soluble in various organic solvents and silicone oils having a small number of SiOH groups and a large number of methyl groups are preferred. Specific examples of the silicone resin powder soluble in the organic solvent include Trefil R-910 (manufactured by Dow Corning Toray).

The amount of the silicone resin is preferably 0.1 to 30 parts by weight based on 100 parts by weight of the elastic polymer. The compounding amount of the silicone resin is
If the amount is less than 0.1 part by weight, the degree of decrease in adhesive strength after UV irradiation after a high-temperature working process is small, and if it exceeds 30 parts by weight, the surface of the pressure-sensitive adhesive layer becomes considerably cloudy and UV irradiation is performed. However, UV may not be transmitted, and a decrease in adhesive strength may not be observed. The blending amount of the silicone resin is more preferably 0.5 to 100 parts by weight of the elastic polymer.
20 parts by weight.

It is preferable that the pressure-sensitive adhesive layer A further contains 1 to 50 parts by weight of silica based on 100 parts by weight of the elastic polymer. If the amount of the silica is less than 1 part by weight, the pressure-sensitive adhesive layer A may remain on the light-transmitting plastic film when peeled off, and if it exceeds 50 parts by weight, the initial adhesive strength is insufficient. Prone. The amount of the silica is more preferably 3 to 30 parts by weight based on 100 parts by weight of the elastic polymer. Further, the pressure-sensitive adhesive layer A may further contain a filler, an antioxidant, a coloring agent, and the like, if necessary.

An appropriate amount of an organic solvent for dissolving the components, such as aromatic hydrocarbons, ketones, or a mixture thereof, is added to each of the components constituting the pressure-sensitive adhesive layer A, and the mixture is dissolved. A solution composition having a uniform composition for forming an agent layer (hereinafter, also referred to as solution composition A) can be obtained, and this solution composition A is applied onto a base resin sheet by a conventionally known method, By drying
The pressure-sensitive adhesive layer A can be formed. As the organic solvent, a mixed solvent of toluene and methyl ethyl ketone is preferable.

The acrylic resin-based pressure-sensitive adhesive and tackifier used as the elastic polymer are usually commercially available in the form of a solution. Therefore, it is convenient to use these commercially available products. , Mixed solutions of these commercial products, the UV-crosslinkable resin, the polymerization initiator,
The above-mentioned polymerization inhibitor and, if necessary, other additives are added and uniformly dissolved to obtain a solution composition A.
May be prepared. The amount of the elastic polymer in the solution composition A is not particularly limited, but is usually 10 to 50.
% By weight is preferred.

The pressure-sensitive adhesive layer A formed on one surface of the adhesive sheet of the present invention firmly adheres to a light-transmitting plastic film placed thereon before irradiation with ultraviolet rays, while The structure is such that the adhesive strength is reduced and the light-transmitting plastic film can be easily peeled off.

An adhesive layer B is formed on the other surface of the base resin sheet. The pressure-sensitive adhesive layer B preferably comprises 100 parts by weight of an elastic polymer and 5 to 150 parts by weight of an ultraviolet-crosslinkable resin. As the elastic polymer, the acrylic resin-based adhesive is preferably used. Since the adhesive sheet of the present invention contains an elastic polymer such as the acrylic resin-based adhesive and an ultraviolet-crosslinkable resin in the adhesive layer B, a liquid crystal display panel is produced using the adhesive sheet of the present invention. When manufactured, the base and the adhesive sheet are firmly adhered to each other, and as a result, the flatness between the light-transmitting plastic film and the adhesive sheet is increased. Examples of the acrylic resin-based pressure-sensitive adhesive and the ultraviolet-crosslinkable resin include, for example, those similar to the acrylic resin-based pressure-sensitive adhesive and the ultraviolet-crosslinkable resin used in the pressure-sensitive adhesive layer A.

When preparing the pressure-sensitive adhesive layer B, the UV-crosslinkable resin 5 to 100 parts by weight of the elastic polymer is used.
It is preferable to add 150 parts by weight. If the amount of the ultraviolet-crosslinkable resin is less than 5 parts by weight, bubbles may easily be generated between the light-transmitting plastic film and the adhesive sheet. On the other hand, if it exceeds 150 parts by weight,
Sufficient adhesiveness may not be obtained between the pressure-sensitive adhesive layer B and the substrate. More preferably, the elastic polymer 100
10 to 100 parts by weight of the ultraviolet-crosslinkable resin is added to the parts by weight. In addition, a weight part shows the ratio of the weight of a solid content.

The pressure-sensitive adhesive layer B further comprises an elastic polymer 10
It is preferable to contain 0.01 to 5 parts by weight of a polymerization inhibitor with respect to 0 parts by weight. By containing the polymerization inhibitor, the polymerization hardly proceeds by heating or the like, so that the adhesiveness between the adhesive sheet and the substrate does not decrease even after the working process at a high temperature. When the amount of the polymerization inhibitor is less than 0.01 part by weight based on 100 parts by weight of the elastic polymer,
Polymerization may be caused by factors other than ultraviolet irradiation such as heating, and even if the amount exceeds 5 parts by weight, no further improvement in the effect of preventing polymerization is observed. The amount of the polymerization inhibitor is more preferably 0.05 to 100 parts by weight of the elastic polymer.
~ 2 parts by weight.

The pressure-sensitive adhesive layer B further comprises an elastic polymer 10
It is preferable to contain 1 to 50 parts by weight of silica with respect to 0 parts by weight. If the amount of the silica is less than 1 part by weight or more than 50 parts by weight, the adhesive strength tends to be insufficient. More preferably, the amount of the silica is 3 to 30 parts by weight based on 100 parts by weight of the elastic polymer.

The pressure-sensitive adhesive layer B may further contain, if necessary, a tackifier, a filler, an antioxidant, a coloring agent and the like. As the tackifier, polymerization inhibitor and silica, for example, a tackifier used in the pressure-sensitive adhesive layer A,
Examples thereof include those similar to the polymerization inhibitor and silica.

The pressure-sensitive adhesive layer B formed on the other side of the adhesive sheet of the present invention does not change its adhesiveness before and after irradiation with ultraviolet light, and firmly adheres to the base resin sheet and the fixing base. It is configured as follows.

The fixing base is not particularly limited as long as it can hold the translucent plastic film in a fixed shape in a three-dimensional sense, and examples thereof include a glass plate.

The adhesive sheet of the present invention is used for preparing a liquid crystal display panel after forming the pressure-sensitive adhesive layer A on one surface of the base resin sheet and forming the pressure-sensitive adhesive layer B on the other surface. Or the above-mentioned pressure-sensitive adhesive layer A and pressure-sensitive adhesive layer B,
A release film may be attached to the surface opposite to the surface in contact with the base resin sheet. By sticking the release film in this way, once the adhesive sheet is produced, it is protected so that dust or dust does not adhere to the adhesive layer when it is stored or transported. be able to.
Examples of the release film include a polyethylene terephthalate film and a silicone film.

In the manufacturing process of the liquid crystal display panel, when various layers are formed on the translucent plastic film by using a physical method or a chemical method, various forces are applied to the translucent plastic film. The transparent plastic film acts on the transparent plastic film, but the transparent plastic film needs to be firmly fixed to the base in order to smoothly carry out the above-mentioned manufacturing process. Since the adhesive sheet of the present invention is configured so as to be firmly bonded to and integrated with the translucent plastic film for the liquid crystal display panel and the fixing base disposed thereunder, The plastic film does not shift, wrinkle, break or the like.

In the adhesive sheet of the present invention, the adhesive strength between the adhesive sheet and the translucent plastic film and the fixing substrate at room temperature before irradiation with ultraviolet light is 1N / 25.
mm or more. This is because various large forces act at room temperature in the process of manufacturing the liquid crystal display panel.

On the other hand, even if the adhesive sheet of the present invention is adhered to the above-mentioned substrate even when irradiated with ultraviolet rays, the adhesive sheet of the present invention and the above-mentioned substrate remain firmly adhered. By this ultraviolet irradiation, the adhesive strength between the adhesive sheet of the present invention and the translucent plastic film is reduced, and the adhesive sheet of the present invention can be easily peeled from the translucent plastic film. In order to perform peeling more easily, the adhesive force between the adhesive sheet and the translucent plastic film at room temperature after irradiation with ultraviolet light is
It is preferably 0.2 N / 25 mm or less.

As described above, only the adhesive force between the adhesive sheet and the light-transmitting plastic film is reduced after the irradiation with the ultraviolet light. As a result, for example, a plurality of layers are formed on the light-transmitting plastic film and the liquid crystal is formed. When the step of manufacturing the display panel is completed, for example, the adhesive sheet of the present invention can be easily peeled off by irradiating ultraviolet rays using a high-pressure mercury lamp, and the intended lamination for a liquid crystal display panel is performed. A body or the like can be easily obtained.

The method of irradiating the pressure-sensitive adhesive layer with ultraviolet light is not particularly limited, and a conventionally used method can be used. For example, a xenon lamp, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, or an ultra-high pressure A method of irradiating for several seconds to several minutes using an ultraviolet light source such as a mercury lamp can be used.

Since the adhesive sheet of the present invention has the above-described structure, it has a strong adhesiveness to the substrate and the translucent plastic film even when heated, and does not generate irregularities. Therefore, when a liquid crystal display panel is manufactured using the adhesive sheet of the present invention, even after passing through a high-temperature atmosphere during the heating step, the adhesiveness between the translucent plastic film and the adhesive sheet is strong, and Since the interface between the adhesive sheet and the translucent plastic film is kept flat, the surface smoothness of the translucent plastic film is also kept well.

[0049]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, the compounding amount of each component in the following Examples and Comparative Examples is parts by weight of the solid content.

Examples 1 to 3 and Comparative Examples 1 and 2 The amounts of the elastic polymer, the UV-crosslinkable resin, the photopolymerization initiator, the tackifier, the polymerization inhibitor, the silica and the silicone resin in the amounts shown in Table 1 were used in containers. Then, methyl ethyl ketone (MEK) was added and mixed so that the solid content became 35% by weight to prepare a solution composition A for forming the pressure-sensitive adhesive layer A.

Separately from the above-mentioned solution composition A, an acrylic resin-based pressure-sensitive adhesive, an ultraviolet-crosslinkable resin, a polymerization inhibitor and silica having the compounding amounts shown in Table 1 were used as containers, and the solid content was 3%.
MEK was added and mixed at 5% by weight to prepare a solution composition B for forming the pressure-sensitive adhesive layer B.

Next, the solution composition A was coated on one surface of a polyethylene terephthalate film (PET film) having a thickness of 38 μm and dried at 120 ° C. for 1 minute to form an adhesive layer A having a thickness of 20 μm. Thereafter, a release PET film was attached to protect the pressure-sensitive adhesive layer A.

Separately, the solution composition B was coated on a release PET film and dried at 120 ° C. for 1 minute to form an adhesive layer B having a thickness of 10 μm. An adhesive sheet was produced by attaching the B side to another surface of the PET film on which the pressure-sensitive adhesive layer A was formed by lamination transfer.

Preparation of Test Piece for Surface Smoothness Measurement The obtained adhesive sheet was cut into a width of 50 mm and a length of 100 mm, and the release PET film was peeled off.
The side is overlapped on a glass plate so as not to form bubbles, and adhered to each other. Thereafter, a polycarbonate film (PC film) having a chemical resistant layer containing no inorganic compound on the pressure-sensitive adhesive layer A is laminated so as not to form bubbles, A test piece was prepared by reciprocating 5 times with a 3 kg roller and pressing and contacting it, and left at room temperature for 20 minutes.

The obtained test pieces were evaluated for surface smoothness (with or without irregularities) at a temperature of 120 ° C. before irradiation with ultraviolet rays by the following method. The results are shown in Table 1. Evaluation method (1) Evaluation of surface smoothness in an atmosphere of 120 ° C. before irradiation with ultraviolet rays A test piece was placed in an oven at 120 ° C. for 2 hours, taken out, and visually observed for surface smoothness (presence or absence of irregularities) using a loupe. Observed. Evaluation criteria A: No unevenness is observed. O: Slight unevenness is observed. X: Unevenness is generated.

[0056]

[Table 1]

The description in Table 1 is as follows. 1) SK Dyne 1823 (manufactured by Soken Kagaku) 2) Aronix M400 (manufactured by Toagosei Co., Ltd.) 3) Pencel D-135 (manufactured by Arakawa Chemical) 4) Irgacure 184 (manufactured by Ciba Specialty Chemicals) 5) Q 1301 (manufactured by Wako Pure Chemical Industries, Ltd.) 6) POLICIC 410SA (manufactured by Sanyo Chemical Industries) 7) Sartomer SR454 (manufactured by Sartomer) 8) Aerosil # 200 (manufactured by Nippon Aerosil) 9) Byron 30SS (manufactured by Toyobo Co., Ltd.) 10) Trefill R-910 (manufactured by Dow Corning Toray)

As shown in Table 1, the adhesive sheets produced in Examples 1 to 3 did not have any irregularities on the surface even when left in a high-temperature atmosphere, and showed no decrease in adhesive strength. Since there was no PC film, the surface smoothness of the PC film was good.
In contrast, the adhesive sheets produced in Comparative Examples 1 and 2
Irregularities occurred when left in a high-temperature atmosphere. this is,
In Comparative Examples 1 and 2, it is considered that the polymerization proceeded by heating and the curing shrinkage occurred because no polymerization inhibitor was added to the pressure-sensitive adhesive layer A.

Examples 4 to 6 and Comparative Examples 3 and 4 The amounts of the elastic polymer, the UV-crosslinkable resin, the photopolymerization initiator, the tackifier, the polymerization inhibitor, the silica and the silicone resin in the amounts shown in Table 2 were placed in a container. Then, methyl ethyl ketone (MEK) was added and mixed so that the solid content became 35% by weight to prepare a solution composition A for forming the pressure-sensitive adhesive layer A.

Separately from the solution composition A, the acrylic resin-based pressure-sensitive adhesive, the UV-crosslinkable resin, the polymerization inhibitor and the silica in the amounts shown in Table 2 were used as containers, and the solid content was 3%.
MEK was added and mixed at 5% by weight to prepare a solution composition B for forming the pressure-sensitive adhesive layer B.

Next, the solution composition A was applied to one surface of a polyethylene terephthalate film (PET film) and dried at 120 ° C. for 1 minute to obtain a 20 μm
After forming the pressure-sensitive adhesive layer A having a thickness of 5 mm, a release PET film was adhered to protect the pressure-sensitive adhesive layer A.

Separately, the above-mentioned solution composition B was applied on a release PET film, and dried at 120 ° C. for 1 minute to form an adhesive layer B having a thickness of 20 μm. An adhesive sheet was produced by attaching the B side to another surface of the PET film on which the pressure-sensitive adhesive layer A was formed by lamination transfer.

Using the obtained adhesive sheet, a test piece was prepared in the same manner as in Example 1 except that a PC film having a chemical-resistant layer containing an inorganic compound was used as a PC film. Was evaluated in the same manner as in Example 1.

[0064]

[Table 2]

The description in Table 2 is as follows. 1) SK Dyne 1823 (manufactured by Soken Kagaku) 2) Aronix M400 (manufactured by Toagosei Co., Ltd.) 3) Pencel D-135 (manufactured by Arakawa Chemical) 4) Irgacure 184 (manufactured by Ciba Specialty Chemicals) 5) Q 1301 (manufactured by Wako Pure Chemical Industries, Ltd.) 6) POLICIC 410SA (manufactured by Sanyo Chemical Industries) 7) Sartomer SR454 (manufactured by Sartomer) 8) Aerosil # 200 (manufactured by Nippon Aerosil) 9) Byron 30SS (manufactured by Toyobo Co., Ltd.) 10) Trefill R-910 (manufactured by Dow Corning Toray)

As shown in Table 2, the adhesive sheets produced in Examples 4 to 6 did not have irregularities on the surface when left in a high-temperature atmosphere, and there was no decrease in adhesive strength. ,
The surface smoothness of the PC film was good. In contrast, the adhesive sheets produced in Comparative Examples 3 and 4 had irregularities when left in a high-temperature atmosphere. This is because, in Comparative Example 3, the polymerization inhibitor was not blended in the pressure-sensitive adhesive layer A,
It is considered that polymerization progressed due to the heating, and curing shrinkage occurred.

[0067]

As described above, the adhesive sheet of the present invention has good adhesion to the translucent plastic film and the substrate even when heated. Also, even if heated,
Since the adhesive sheet does not have unevenness and the flatness of the interface between the adhesive sheet and the light-transmitting plastic film is maintained, the surface smoothness of the light-transmitting plastic film is kept good. As a result, precise operations in the process of manufacturing the liquid crystal display panel can be smoothly performed, and a product having no bending of the final product and excellent surface smoothness can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Taguchi 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical Co., Ltd. (72) Inventor Akihiro Ikeguchi 3-2-15 Meiwadori, Hyogo-ku, Kobe Bando Chemical F term in reference (reference) 2H088 FA03 FA04 MA20 4F100 AA20C AA20E AA20H AK01D AK01E AK42D AK52E AL05C AL05E AL09C AR00A AR00C AR00E AS00A AT00B BA03 BA05 BA10A BA10B BA10C BA10E J14 CA23C14J14 CA23E JN01A YY00C YY00E 4J004 AA10 AA11 AA15 AA18 AB01 AB07 5G435 AA17 BB12 HH02 KK05 KK10

Claims (6)

[Claims] Before irradiation with ultraviolet light, a transparent plastic film for a liquid crystal display panel placed thereon and a fixing base placed thereunder are firmly bonded and integrated, while ultraviolet light is applied. After the irradiation, the adhesive sheet is configured so that the adhesive force with only the light-transmitting plastic film is reduced and the light-transmitting plastic film can be easily peeled off from the substrate and the adhesive sheet. The adhesive sheet comprises a base resin sheet and a UV-curable pressure-sensitive adhesive layer A formed on one surface of the base resin sheet.
And an adhesive layer B formed on the other surface,
The pressure-sensitive adhesive layer A comprises 100 parts by weight of an elastic polymer, 5 to 150 parts by weight of an ultraviolet-crosslinkable resin, 1 to 100 parts by weight of a tackifier, 0.1 to 20 parts by weight of a polymerization initiator, and 0.1 to 20 parts by weight of a polymerization inhibitor.
An adhesive sheet comprising from 0.01 to 5 parts by weight. 2. The adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer A further contains 0.1 to 30 parts by weight of a silicone resin. 3. The adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer A further contains 1 to 50 parts by weight of silica. 4. The adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer B comprises 100 parts by weight of an elastic polymer and 5 to 150 parts by weight of a UV-crosslinkable resin. 5. The pressure-sensitive adhesive layer B further comprises a polymerization inhibitor 0.0
Claim 1 characterized by containing 1 to 5 parts by weight.
The adhesive sheet according to 2, 3 or 4. 6. The pressure-sensitive adhesive layer B further comprises 1 to 50 parts by weight of silica.
Or the adhesive sheet according to 5.