TWI706021B - Adhesive tape - Google Patents

Abstract

Disclosed is an adhesive tape having a laminated substrate and an adhesive layer 5 on at least one side of the laminated substrate, wherein a laminate comprising at least one black print layer 2 on a support 1 and a laminate comprising at least one light colored print layer 3 on a support 1 are bonded to each other on each print layer side via an adhesive layer 4 to form the laminated substrate. The blocking of the laminated substrate and the pinhole caused by peeling of the print layers hardly occur, the properties such as adhesive force can be easily adjusted, the reworkability is excellent, and for example, a silicone based adhesive layer can be easily applied.

Description

Adhesive tape

The present invention relates to a liquid crystal (LCD) display device used in, for example, mobile devices. It is used between the backlight frame and the LCD module and has a single-sided or double-sided adhesive tape with both functions of light reflection and shading.

For example, liquid crystal display devices used in image display devices such as mobile communication terminals, tablet computers, car navigation, mobile game consoles, etc., have an adhesive tape between the liquid crystal display unit and the backlight unit to fix the two components. In addition, the adhesive tape has, for example, a white light reflection layer and a black light-shielding layer, and contributes to the improvement of the brightness of the backlight surface and the prevention of reduced visibility due to light leakage from the backlight. Such an adhesive tape that contributes to both brightness enhancement and light-shielding properties is disclosed in Patent Documents 1 to 6, for example.

The light reflection layer of the adhesive tape disclosed in Patent Document 1 is composed of a biaxially stretched resin film of polyester resin containing a white colorant. However, such a light reflection layer composed of a resin film containing a coloring agent has poor productivity, and adjustment of brightness (reflectance) is also difficult.

The light reflection layer of the adhesive tape disclosed in Patent Document 2 is a white printing layer, and the light-shielding layer is a black printing layer. Compared with the resin film containing the colorant, the printed layer has better productivity and easier adjustment of brightness (reflectance). Therefore, it has been revealed that the white printing layer and the black printing layer are arranged on one side of the transparent plastic substrate. It also discloses a laminated substrate with a white printing layer on one side of the transparent plastic substrate and a black printing layer on the other side. However, when this type of laminated substrate is wound in a roll shape, adhesion occurs between the printed layer and its contact surface. When the next step (adhesive coating step) is rolled back and unfolded, there will be a printed layer in it. A part of it adheres to the contact surface and remains as a spot.

The adhesive tape disclosed in Patent Document 3 is attached to a laminated base material composed of a black printing layer/resin film/white printing layer, and a thin coating layer composed of synthetic rubber, acrylic resin or polyester resin is provided. The thin coating layer is wound to prevent adhesion and peeling of the printed layer. However, because one of the printed surfaces is exposed, the printed layer will adhere to the drive roller, guide roller, or conveyor made of rubber or other materials when it is transported to the adhesive coating part, causing the printed layer to separate from the substrate. Peeling off makes the place a pinhole, which may reduce the shading or light reflectivity.

Defects caused by peeling of the printed layer will also pose a problem when the adhesive tape is peeled off from the LCD panel and other components and re-attached (re-processing). In the adhesive tape of Patent Document 4, in order to improve the adhesion between the substrate and the printing layer, an intermediate layer containing synthetic rubber is provided between the substrate and the printing layer. This prevents interlayer peeling between the substrate and the printed layer when performing heavy processing, and prevents the printed layer and the adhesive layer from remaining on the component. On the other hand, in the adhesive tape disclosed in Patent Document 5, in order to improve the adhesion between the printed layer and the adhesive layer, the adhesive resin of the printed layer uses a polyurethane resin with Tg (tan δ peak temperature) -30°C to 30°C And the hardening agent is aliphatic or cycloaliphatic isocyanate, which can prevent the printing layer from cracking and causing the tape to break during heavy processing.

However, in the adhesive tapes disclosed in Patent Document 4 and Patent Document 5, because the adhesive layer directly contacts the printed layer, there is a gap between the adhesive component and the printed layer component. Interaction occurs, and there may be situations where the required adhesion cannot be obtained. For example, in the adhesive tape disclosed in Patent Document 4, it is described that a crosslinking agent is blended in an acrylic adhesive as necessary. In this case, the cross-linking agent added to the adhesive will be absorbed by the printing layer, resulting in a decrease in the degree of hardening of the adhesive, which may cause the adhesive force to be greater than the product design preset value. In addition, in the adhesive tape disclosed in Patent Document 5, the hardener contained in the adhesive of the printing layer migrates into the adhesive layer, resulting in an increase in the degree of hardening of the adhesive, which may cause the adhesive force to be lower than the product design preset value. Sex. Accordingly, if the adhesive force of only one side of the double-sided adhesive tape changes, resulting in unequal adhesive force on the two sides, the product performance will pose a problem, and there will also be a decrease in reworkability.

The influence of the interaction between the adhesive components and the printing layer components will not only affect the above-mentioned adhesive force, but also almost the necessary physical properties of the adhesive tape such as the retention force and the viscosity of the adhesion index. In addition, because the temperature, humidity, storage time and other environment of the location of the adhesive tape are also affected by the interaction, the verification experiment is complicated. Therefore, the inventors of the present invention believe that it will be more difficult to solve the problem when the adhesive layer is in contact with the printed layer.

However, from the viewpoint of stability against thermal degradation or degradation over time, there are cases in which silicone adhesives with higher durability than general acrylic adhesives are expected. In the case of using silicone adhesives, in order to improve the adhesion to the substrate, the substrate must be primed. However, if a solution in which the primer components have been dissolved is applied to the printed layer, the printed layer will swell due to the organic solvent contained in the primer solution, causing the printed layer to peel off the substrate and cause pinholes.

Patent Document 6 describes that it avoids conduction caused by the coloring components (carbon black, etc.) contained in the light-shielding layer (black printing layer) of the adhesive tape, and focuses on the type of substrate, the type of adhesive layer, the type of light-shielding layer, and the reflective layer. Types, and the order of layers, etc. Make various combinations. However, in the various layer structures of the adhesive tape, for example, the layer structure when the white printing layer and the black layer printing layer are in direct contact, because the white printing layer is formed on one substrate, and the black layer is formed by many times of printing on it. Layer printing layer (refer to the example), as the number of printing increases, the smoothness of the printing layer surface will be lost. As a result, there may be changes in the adhesion characteristics or sagging (gap between layers) when winding on a roller. Sex.

[Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2004-156015

Patent Document 2: Japanese Patent Laid-Open No. 2009-197124

Patent Document 3: Japanese Patent Laid-Open No. 2011-95764

Patent Document 4: International Publication No. 2009/020043

Patent Document 5: Japanese Patent Laid-Open No. 2010-53240

Patent Document 6: Japanese Patent Laid-Open No. 2011-214010

The purpose of the present invention is to provide: an adhesive tape with both light reflectivity and light-shielding functions, is not prone to build-up substrate adhesion, pinholes due to peeling of the printed layer, easy to adjust physical properties such as adhesion, and excellent in reworkability. It can be easily applied to adhesive tapes such as silicone adhesive layers.

The inventors of the present invention have intensively studied to achieve the above-mentioned object and found that the use of a laminated base material with a specific layer composition is very effective, and completed the present invention.

That is, the adhesive tape of the present invention is provided with: a laminated base material and an adhesive layer provided on at least one side of the laminated base material; wherein the laminated base material is a layer in which at least one black printing layer is laminated on a support A laminated body and a laminated body in which at least one bright-color printing layer is laminated on a support body are formed by joining one side of the printed layer side to each other via an adhesive layer.

Because the printed layer of the adhesive tape of the present invention exists on the inner side of the support, it is not prone to sticking or pinholes due to peeling of the printed layer. As a result, the light shielding property or the reduction of light reflectivity can be prevented. In addition, because the printed layer and the adhesive layer are not in contact, there will be no component migration between the adhesive layer and the printed layer, and the physical properties such as the adhesive force can be easily adjusted. The reworkability is also excellent, and it can be easily applied to substrates such as substrates. The surface is treated with a primer layer of silicone adhesive.

1a, 1b‧‧‧Support

2‧‧‧Black printing layer

3‧‧‧Bright color printing layer

4‧‧‧Adhesive layer

5a, 5b‧‧‧Adhesive layer

6‧‧‧Primer treatment layer

7‧‧‧Polycarbonate board

8‧‧‧Test piece (adhesive tape)

9‧‧‧hammer

10‧‧‧Test piece (adhesive tape)

11‧‧‧Adhesive film

Fig. 1 is a schematic cross-sectional view of an embodiment of the adhesive tape (double-sided) of the present invention.

Fig. 2 is a schematic cross-sectional view of an embodiment of the adhesive tape (single side) of the present invention.

Fig. 3 is a schematic cross-sectional view for explaining the constant-weight peel test of the embodiment and the comparative example.

Fig. 4 (a) and (b) are schematic plan views for explaining the method of evaluating the adhesion of the substrates of the examples and the comparative examples.

Figure 1 shows a schematic cross-sectional view of an embodiment when the adhesive tape of the present invention is a double-sided adhesive tape. In this embodiment, the laminated base material is composed of a laminated body in which a black printing layer 2 is laminated on a support 1a, and a laminated body in which a bright color printing layer 3 is laminated on a support 1b, so that the printed layers 2 and 3 are mutually close to each other. One side, through the adhesive layer 4 Joined together. Then, the adhesive layers 5a and 5b are provided on both sides of the laminated base material. This type of laminated structure, because the black printing layer 2 (light-shielding layer) and the bright color printing layer 3 (light reflection layer) are not directly in contact with the adhesive layers 5a and 5b, respectively, so the adhesive layer 5 and the printing layers 2 and 3 There will be no component migration between the components, which can solve the problem of interaction between the components of the adhesive layer and the components of the printing layer. As a result, the adjustment of the adhesive composition to obtain the desired adhesive force tends to be easy, and yellowing of the adhesive layer is less likely to occur. Moreover, it is easy to adjust the thickness of the printed layer of the black printed layer 2 (light-shielding layer) and the bright-colored printed layer 3 (light reflection layer), and the addition amount of ink components.

Furthermore, because the laminated base material of the present invention has the above-mentioned specific layer structure, immediately after the laminated base material is manufactured (before the formation of the adhesive layer 5), when the laminated base material is wound up in a roll, the printed layers are still different from each other. It will touch, it is not easy to cause adhesion and pinholes due to peeling of the printed layer. As a result, it is possible to prevent the reduction in light-shielding properties or reflectivity, and it is also excellent in heavy workability.

The adhesive tape shown in FIG. 1 is a preferred embodiment of the present invention, but the present invention is not limited to this. For example, the adhesive tape shown in Figure 1 is a double-sided adhesive tape with adhesive layers 5a and 5b on both sides of the laminated substrate, but it can also be shown in Figure 2 where the adhesive layer 5a is provided only on one side Single-sided adhesive tape. In addition, in the adhesive tape shown in FIG. 2, a primer treatment 6 is provided between the adhesive layer 5a and the black printing layer 2. When an adhesive layer composed of a silicone adhesive is formed on the substrate, the surface of the substrate coated with the silicone adhesive must be primed. However, it is generally quite difficult to perform primer treatment on the printed layer. On the other hand, because the laminated substrate of the present invention has a structure in which the printed layers 2 and 3 are sandwiched by the supports 1a and 1b, the primer treatment is relatively easy, and it can be easily applied to the silicone adhesive layer.

Furthermore, for example, the adhesive tape shown in Figure 1 is composed of 1 black printing layer 2 It is a light-shielding layer, but if necessary, the light-shielding layer may be composed of two or more black printing layers 2. In addition, the adhesive tape shown in FIG. 1 consists of a light-reflecting layer composed of one bright-color printing layer 3, but a laminate of two or more bright-color printing layers 3 may constitute the light-reflecting layer if necessary.

Furthermore, the adhesive tape shown in FIG. 1 is attached to the support 1a or 1b, and the black printing layer 2 or the bright color printing layer 3 is directly laminated, but it can also be between the support 1a and the black printing layer 2, or on the support There are other arbitrary layers between 1b and the bright color printing layer 3. In addition, the adhesive tape shown in FIG. 1 is tied to the outer surface of the support 1a or 1b to directly laminate the adhesive layer 5a or 5b, but any other layer may be present between each outer surface and the adhesive layer 5a or 5b.

[Support 1a and 1b]

The supports 1a and 1b of the present invention are not particularly limited, and the adhesive tape can be used to enable users. For example, resin film, non-woven fabric, paper, cloth, etc., and combinations thereof can be used. Among them, a resin film is preferred, and a transparent or semi-transparent plastic film is more preferred. Specific examples include polyester resins, polypropylene resins, polycarbonate resins, polystyrene resins, polyethylene resins, acrylic resins, polyacetal resins, acetate resins, and polyether resins. Resin, polyolefin resin, fluorine resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin. Especially from the viewpoints of economy, processability, ease of use, etc., polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate are preferred, and From the viewpoint of market versatility (grade richness), etc., polyethylene terephthalate is more preferable.

The thickness of the supports 1a and 1b is usually 2-100 μm, preferably 3-50 μm, more preferably 6-25 μm, particularly preferably 6-12 μm.

[Black Printing Layer 2]

The black printing layer 2 of the present invention is not particularly limited, and various known black printing layers that can impart necessary light-shielding functions to this type of adhesive tape can be used. The black printing layer 2 is usually formed by a known printing method using an ink composition. The ink composition contains, for example, a coloring component (ink component), a binder resin, and a curing agent.

Specific examples of the coloring component (ink component) used in the black printing layer 2 include carbon black, acetylene black, graphite, iron oxide, copper oxide, aniline black, and activated carbon. Specific examples of binder resins include, for example, polyurethane resins, phenol resins, epoxy resins, acrylic resins, polyester resins, polyolefin resins, natural rubber, styrene butadiene rubber, butylene Diene rubber, ethylene propylene rubber. Among them, polyurethane resins are preferred. Specific examples of the curing agent include isocyanate curing agents, epoxy curing agents, melamine curing agents, and aziridine curing agents. The composition ratio of each component can be a known composition ratio, and it may be appropriately determined as necessary.

The ink composition used in the black printing layer 2 can be obtained, for example, by blending a curing agent with a commercially available printing ink containing a coloring component (ink component) and a binder resin.

The thickness of the black printing layer 2 is usually 0.5 to 10 μm, preferably 0.5 to 6 μm, more preferably 1 to 5 μm, and most preferably 2 to 4 μm. The black printing layer 2 may be a single layer to form a light-shielding layer, or a plurality of black printing layers 2 may be laminated to form a light-shielding layer.

Specific examples of the printing method of the ink composition include, for example, gravure printing, elastic printing, offset printing, relief printing, screen printing, stencil printing, and letterpress printing.

[Bright color printing layer 3]

The bright color printing layer 3 of the present invention is not particularly limited, and various known bright color printing layers that can impart the necessary light reflection function to the adhesive tape can be used. The bright color printing layer 3 can adjust the brightness (reflectance) of the light reflection layer more easily than the light reflection layer composed of a resin film containing a colorant as described in Patent Document 1. The so-called "bright color" here refers to colors such as white and light colors that can impart light reflection functions. Especially good white. Specifically, the L* (luminance) specified by the L*a*b* chromaticity system of the bright-color printing layer 3 is preferably 65 or more, more preferably 75 or more. The reflectance of the bright printing layer 3 to a wavelength of 550 nm is preferably 45% or more, more preferably 65% or more. In addition, the average reflectance for a wavelength of 380 to 780 nm is preferably 40% or more, and more preferably 60% or more.

The bright color printing layer 3 is usually formed by using an ink composition and a known printing method. The ink composition contains, for example, a coloring component (ink component), a binder resin, and a curing agent.

Specific examples of the coloring component (ink component) used in the bright printing layer 3 include, for example, titanium oxide and zinc oxide. Specific examples of the binder resin and curing agent are the same as the specific examples of the black printing layer 2. The composition ratio of each component may adopt a known composition ratio, and may be appropriately determined as necessary.

The ink composition system used in the bright color printing layer 3 can be obtained, for example, by blending a hardener in a commercially available printing ink containing a coloring component (ink component) and a binder resin.

The thickness of the bright color printing layer 3 is usually 0.5-10 μm, preferably 0.5-6 μm, more preferably 1-5 μm, particularly preferably 2-4 μm. The bright color printing layer 3 can be a single layer to constitute a light reflection layer, or a plurality of bright color printing layers 3 can be laminated to constitute a light reflection layer.

[Adhesive layer 4]

The present invention consists of a laminated body in which a black printing layer 2 is laminated on a support 1a and a laminated body in which a bright-color printing layer 3 is laminated on a support 1b, with the adhesive layer 4 interposed on one side of the printed layers 2 and 3 Join. Therefore, compared to, for example, the black layer printed layer 2 is formed by sequentially stacking printing on the white printed layer 3, the smoothness of the printed layer surface can be improved, and as a result, there will be no change in adhesion characteristics or winding on the roller. The possibility of sagging (the gap between layers) occurs at times.

The adhesive used in the adhesive layer 4 of the present invention is not particularly limited, and various well-known adhesives can be used within a range that does not hinder the function of the adhesive tape. Specific examples include, for example, polyurethane-based adhesives, polyester-based adhesives, acrylic-based adhesives, and epoxy-based adhesives. Especially from the point of view of adhesion with the printing layers 2 and 3, it is best to use the same type of adhesive as the binder resin of the printing layer. That is, when the binder resin of the printing layers 2 and 3 is a polyurethane resin, it is preferably a urethane adhesive, and when the binder resin is a polyester resin, it is preferably a polyester adhesive. . However, under the premise that sufficient adhesive force can be obtained, an adhesive in a form different from the binder resin can also be used.

The adhesive layer 4 can also be colored if necessary. In particular, it is preferable to add the same coloring component (ink component) as the coloring component (ink component) used in the bright-color printing layer 3 which is a light reflection layer, which can be colored into a bright color. Thereby, the light reflectivity, which is more difficult to adjust than the light shielding property, can be easily adjusted.

A well-known coating method can be used for the coating method of the adhesive agent. Specific examples include, for example, a direct gravure method, a roll anastomosis method, a chamber doctor method, and a lithographic/gravure method. Among them, from the use of the depth of the plate (the depth of the concave portion of the plate) From the viewpoint of selecting and easily controlling the coating thickness, the direct gravure coating method is preferred.

The thickness of the adhesive layer 4 is usually 0.5 to 10 μm, preferably 0.5 to 6 μm, more preferably 1 to 5 μm, particularly preferably 2 to 4 μm.

[Adhesive layer 5a and 5b]

The adhesives used in the adhesive layers 5a and 5b of the present invention are not particularly limited, and various known adhesives that can be used with such adhesive tapes can be used. Specific examples include transparent adhesives such as acrylic adhesives, rubber adhesives, urethane adhesives, polyester adhesives, and silicone adhesives. Among them, acrylic adhesives, urethane adhesives, and silicone adhesives with high transparency are preferred.

Specific examples of acrylic adhesives used in the adhesive layers 5a and 5b include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, ( (Meth) butyl acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, etc. ) Acrylate monomer as the main component, by combining it with monomers containing functional groups such as (meth)acrylic acid, crotonic acid, fumaric acid, itaconic acid, (anhydrous) maleic acid, etc. Or an acrylic adhesive obtained by copolymerizing monomers such as vinyl acetate, acrylonitrile, styrene, 2-hydroxyethyl (meth)acrylate, 2-hydroxymethylethacrylamide, etc., if necessary.

A specific example of the urethane-based adhesive used in the adhesive layers 5a and 5b is an adhesive whose main component can be obtained by curing a polyol and a polyfunctional isocyanate compound to obtain a polyurethane-based resin. Specific examples of polyols include polyester polyols, polyether polyols, polycaprolactone polyols, and polycarbonate polyols. As the polyfunctional isocyanate compound system, known polyfunctional aliphatic isocyanate compounds and polyfunctional aromatic isocyanate compounds that can be used in the amination reaction can be used.

The silicone adhesives used in the adhesive layers 5a and 5b are generally adhesives based on a mixture of silicone rubber and silicone resin. Specific examples of the silicone rubber include, for example, organopolysiloxane containing dimethylsiloxane as a constituent unit. Functional groups (for example, vinyl groups) can also be introduced into the organopolysiloxane as necessary. A specific example of the polysiloxane resin may be, for example, a polysiloxane resin in which a polyfunctional organosiloxane constituent unit is condensed with a monofunctional organopolysiloxane.

Especially when it is not a silicone adhesive, a tackifying resin or a crosslinking agent (hardener) may be added to the adhesive layers 5a and 5b as necessary. Specific examples of the tackifier resin include, for example, rosin resin, polyterpene resin, petroleum resin, terpene phenol resin, and polystyrene resin. Specific examples of the curing agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. In addition, if necessary, you can also add such as: vulcanizing agent, plasticizer, pigment, dye, filler, anti-aging agent, conductive material, antistatic agent, ultraviolet absorber, light stabilizer, peeling regulator, softening agent, interface active Additives such as agents, flame retardants, and antioxidants.

The adhesive layers 5a and 5b can also be colored as needed. For example, the adhesive layer 5a on the side of the black printing layer 2 may be colored black, and the adhesive layer 5b on the side of the bright printing layer 3 may be colored in a bright color.

A well-known method can be used for the coating method of the adhesive agent. Specific examples include: direct gravure method, roll anastomosis method, precision doctor blade method, lithography/gravure method, roll coating method, reverse light touch method, top feed reverse method, bottom feed reverse method, mold coating Cloth method, lip coating method, hot melt coating method, knife coating method, Rolling method. Among them, from the viewpoint of easy layer thickness control, a roll coating method, a die coating method, a lip coating method, and a hot melt coating method are preferred.

The thickness of the adhesive layers 5a and 5b is usually 1 to 200 μm, preferably 3 to 80 μm, more preferably 5 to 50 μm, particularly preferably 10 to 30 μm.

[Laminated base material]

The laminated base material of the present invention is composed of a laminated body in which at least one black printing layer 2 is laminated on the support 1 described above, and a laminated body in which at least one bright color printing layer 3 is laminated on another support 1 so as to be mutually The printed layer 2 and 3 sides are a substrate formed by bonding through the adhesive layer 4. The thickness of the laminated base material is appropriately determined according to the required thickness of the adhesive tape. The thickness of the laminated substrate is preferably 5.5 to 230 μm, more preferably 18 to 36 μm.

The surface of the laminated base material can be primed if necessary. Especially when at least one of the adhesive layers contains a silicone-based adhesive, in order to improve the adhesion between the laminated substrate and the adhesive layer, the surface of the laminated substrate is preferably treated with a primer. The kind of primer is not particularly limited, and for example, a commercially available silicone primer can be used.

[Adhesive tape]

The adhesive tape of the present invention is provided with the above-described laminated base material and an adhesive tape having an adhesive layer 5 provided on at least one surface of the laminated base material. The adhesive tape of the present invention may be provided with layers or members other than the laminated base material and the adhesive layer within the range that does not impair the effects of the present invention. For example: release liners such as release paper or release film; back treatment layer for single-sided tape; antistatic layer for obtaining antistatic properties; functional layer for improving shielding characteristics, heat dissipation characteristics, etc. Wait.

[Example]

Hereinafter, the present invention will be further described by the embodiments, but the present invention is not limited to this. In the following description, "parts" means "parts by mass".

<Example 1>

(Preparation of black ink composition)

To 100 parts of commercially available black ink (manufactured by Toyo Ink Co., Ltd., trade name E039PETAK94 ink) containing coloring components and binder resin, blended with an isocyanate-based hardener (manufactured by Toyo Ink Co., Ltd., trade name TK HARDENERXB) 8.0 It was diluted with 9 parts of a mixed solvent (mass ratio=1:1) of toluene and MEK (methyl ethyl ketone) to obtain a black ink composition.

(Preparation of bright color ink composition)

To 100 parts of commercially available white ink (manufactured by Toyo Ink Co., Ltd., trade name E039PET63 white) containing coloring components and binder resin, blended with an isocyanate-based hardener (manufactured by Toyo Ink Co., Ltd., trade name TK HARDENERXB) 6.0 It was diluted with 26 parts of a mixed solvent of toluene and MEK (mass ratio=1:1) to obtain a bright ink composition.

(Preparation of Adhesive Composition)

With respect to 100 parts of a commercially available polyester adhesive (manufactured by Toyo-Morton Co., Ltd., trade name AD-76P1), a commercially available white ink (manufactured by Toyo Ink Co., Ltd., product E039PET63 white) 40 parts, and isocyanate-based hardener (Toyo-Morton Co., Ltd. product, trade name CAT-RT85) 12.0 Part, diluted with 110 parts of toluene to obtain an adhesive composition A colored white.

(Preparation of adhesive composition)

With respect to 100 parts of acrylic adhesive material (manufactured by Saiden Chemical Co., Ltd., SAIVINOL (registered trademark) SN-007), 0.9 part of isocyanate-based hardener (manufactured by Saiden Chemical Co., Ltd., brand name hardener AL) is blended, Dilute with 90 parts of ethyl acetate to obtain an adhesive composition.

(Production of laminated base material A)

On one side of a transparent PET film with a thickness of 6μm used as the support 1a, gravure printing was performed using the black ink composition prepared previously (gravure roll: 75 lines/plate depth 140μm), and matured at 40°C for 2 days The black printing layer 2 with a thickness of 5 μm is formed. On the other hand, on one side of a transparent PET film with a thickness of 6 μm used as the support 1b, gravure printing was performed using the bright ink composition prepared therefrom (gravure roll: 110 lines/plate depth 90 μm), and the thickness was 40 After aging at ℃ and 2 days, a bright color printing layer 3 with a thickness of 3μm is formed [L*(brightness)=65, average reflectivity to wavelength 380~780nm=61%]. Next, on the bright color printing layer 3, the previously prepared adhesive composition was coated with a gravure coater (gravure roll: 110 lines/plate depth 95 μm) to form an adhesive layer 4 with a thickness of 3 μm. Then, the adhesive layer 4 and the black printing layer 2 of the support 1a are bonded together, and aged at 40°C for 3 days to obtain the support 1a/black printing layer 2/adhesive layer 4/bright color printing layer 3/ The supporting body 1b is composed of a laminated base material A with a total thickness of 23 μm.

(Making of double-sided adhesive tape)

On the release surface of the release film (manufactured by Nakamoto Packs Co., Ltd., trade name MA25) treated with silicone on one side of the resin film, apply the previously prepared adhesive composition by roll coating. The thickness of the adhesive layers 5a and 5b after drying was set to 18.5 μm, and the solvent (ethyl acetate) was removed by drying in a drying oven. The adhesive composition layer on the release film was attached to both sides of the previously produced laminated base material A, and aged at 40°C for 3 days to obtain the adhesive layer 5a/ shown in Figure 1 Support 1a/black printing layer2/adhesive layer 4/bright color printing layer3/support 1b/adhesive layer 5b is a double-sided adhesive tape.

<Comparative Example 1>

(Production of laminated base material B)

On one side of a transparent PET film with a thickness of 12 μm used as the support 1b, the bright ink composition prepared in Example 1 was used for gravure printing (gravure roll: 110 lines/plate depth 90 μm), and the temperature was heated at 40°C and 2 After maturation, the bright color printing layer 3 with a thickness of 6 μm is formed. Next, on the bright color printing layer 3, gravure printing was performed using the black ink composition adjusted in Example 1 (gravure roll: 75 lines/plate depth 140μm), and after aging at 40°C for 2 days, a thickness of 5μm was formed. The black printing layer 2 obtains a laminated base material B formed by a configuration of the color printing layer 2 / bright color printing layer 3 / support 1 b.

(Making of double-sided adhesive tape)

On both sides of the laminated base material B, the adhesive layers 5a and 5b were formed in the same manner as in Example 1, to obtain the adhesive layer 5a/black printing layer 2/bright color printing layer 3/support 1b/adhesive layer Double-sided adhesive tape formed by the composition of 5b.

<Comparative Example 2>

(Making of double-sided adhesive tape)

Except that the thickness of the dried adhesive layer 5a was changed to 15 μm, and the thickness of the dried adhesive layer 5b was changed to 22 μm, the rest were obtained in the same manner as in Comparative Example 1. The adhesive layer 5a/ Black printing layer 2 / bright color printing layer 3 / support 1b / adhesive layer 5b is formed by a double-sided adhesive tape.

For the double-sided adhesive tapes obtained in Example 1 and Comparative Examples 1 and 2, evaluation was performed according to the following methods. The results are shown in Table 1.

(Adhesion to SUS)

According to JIS Z 0237 (2000), the adhesion to the SUS board was measured.

(Penetration concentration)

Using a portable black and white transmission densitometer (manufactured by Ihara Electronics Co., Ltd., trade name TM-5), the penetration concentration of the double-sided adhesive tape was measured. Because the measurement range of the device is 0.0 to 6.0, the penetration concentration exceeding this range is marked as "6.0 or above".

(Reflectivity)

Using an ultraviolet-visible-infrared spectrophotometer (manufactured by JASCO Corporation, trade name V-670), the average reflectance was measured in the wavelength range of 380 to 780 nm.

(Holding power, stickiness)

According to JIS Z 0237 (2000), the retention and viscosity are measured. However, the relevant retention force is measured under the conditions of an adhesive area of 20×20 mm, a load of 1 kg, a heating temperature of 70°C, and a heating time of 60 minutes.

(Adhesion to PC)

The adhesion to the polycarbonate board was measured in accordance with JIS Z 0237 (2000).

<evaluation>

From the results shown in Table 1, it was found that the adhesive tape of Example 1 was excellent in all physical properties, and the black side and the bright side had almost the same adhesion, retention, and tack. In addition, the layer structure does not cause print peeling or pinholes during the manufacturing process. In addition, heavy processing can be performed without worry.

On the other hand, the adhesive tape of Comparative Example 1 where the black printing layer 2 is in contact with the adhesive layer 5a, the adhesion, retention, and tackiness of the adhesive layers 5a and 5b on both sides appear Great deviation. This phenomenon can be thought to be due to the fact that part of the hardener added to the acrylic adhesive of the adhesive layer 5a is absorbed by the black printing layer 2, resulting in a decrease in the degree of hardening of the adhesive layer 5a. As a result, the adhesive tape of Comparative Example 1 may have adhesive residue on the black side (adhesive layer 5a side) (part of the adhesive remains during peeling) or poor initial adhesion, and may also have poor reworkability.

The adhesive tape of Comparative Example 2 is the same as Comparative Example 1. The black printing layer 2 will contact the adhesive layer 5a, but there are also attempts to adjust the thickness of the two adhesive layers 5a and 5b to make the adhesive force on both sides equal的例。 Examples. As a result, the adhesion to SUS becomes equal. However, the black side (adhesive layer 5a side) has too low adhesion and tackiness to PC, and the bright side (thick adhesive layer 5b side) has too high adhesion. As a result, the adhesive tape of Comparative Example 2 has the possibility that the black side (adhesive layer 5a side) may have poor initial adhesion and peeling, while the bright side (thick adhesive layer 5b side) may cause work due to adhesion. Possibility of poor sex.

Next, with respect to the double-sided adhesive tape obtained in Example 1 and Comparative Example 2, the following constant-load peel test was performed. The results are shown in Table 2.

(Constant load peel test)

As shown in Figure 3, a test piece 8 (adhesive tape) with a width of 20 mm × a length of 50 mm is pasted on the polycarbonate plate 7, and 1 reciprocating pressure bonding is performed with a 2 kg roller. The normal condition is maintained for 20 minutes, and then the angle is 90° Use 100g hammer 9 to hang. In this state, it was stored in a 70° C. dryer for 60 minutes, and the deviation distance (mm) of the test piece 8 or the drop time of the hammer 9 at this time was measured. This measurement was carried out in the initial stage, after 3 days, 7 days, and 14 days. The results are shown in Table 2.

[Table 2]

<evaluation>

From the results shown in Table 2, it is known that the adhesive tape of Example 1 caused less deviation with time. Therefore, even during secondary processing such as punching processing, no adhesive will adhere to the guide roller together with the printed layer, and it is predicted that even after long-term storage, there will be no defects in the process in use. On the other hand, in the adhesive tape of Comparative Example 2, the black side (adhesive layer 5a side) has a large deviation over time.

<Example 2>

(Preparation of adhesive composition)

With respect to 100 parts of silicone adhesive raw material (Toray‧Dow Corning Co., Ltd. product, trade name SD-4580), 0.9 part of catalyst (Toray‧Dow Corning Co., Ltd. product, trade name NC25) is added, An appropriate amount of toluene is used to obtain an adhesive composition.

(Preparation of primer composition)

With respect to 100 parts of polysiloxane-based primer raw material main agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KR-3006A), 10 parts of auxiliary agent (manufactured by Shin-Etsu Chemical Co., Ltd. trade name KR-3006BT) is blended , Catalyst (Shin-Etsu Chemical Industry Co., Ltd. Manufacture, trade name CAT-PS-8S) 0.5 part, add appropriate amount of toluene, obtain primer composition.

(Production of laminated base material A')

On the surface of the support 1a of the laminated base material A produced in Example 1, the previously prepared primer composition was coated with a roll kiss film to form a primer treatment layer 6 to obtain a laminated base材A'.

(Production of single-sided adhesive tape)

On the primer treatment layer 6 of the laminated base material A', the thickness of the adhesive layer 5a after drying becomes 30μm. The adhesive composition prepared previously is coated by a roller coating method, and then the solvent (toluene) is dried by a dryer. ) To obtain a single side formed by the composition of adhesive layer 5a/primer treatment layer 6/support 1a/black printing layer 2/adhesive layer 4/bright printing layer 3/support 1b as shown in Figure 2. Adhesive tape.

<Reference example 1>

(Production of single-sided adhesive tape)

Except that the primer treatment layer 6 is not formed, everything else is the same as in Example 2. The composition of the adhesive layer 5a/support 1a/black printing layer 2/adhesive layer 4/bright printing layer 3/support 1b is obtained The formed single-sided adhesive tape.

<Comparative Example 3>

(Production of laminated base material B')

Except that the support 1b uses a transparent PET film with a thickness of 6 μm, the rest is the same as the laminated base material B of Comparative Example 1, and a black printing layer 2 / bright color printing layer 3 / The laminated base material B'formed by the structure of the support 1b.

(Production of single-sided adhesive tape)

Except for using the build-up base material B', everything else was the same as in Example 2. A single sheet formed by the composition of the adhesive layer 5a/primer treatment layer 6/black printing layer 2/bright printing layer 3/support 1b was obtained. Face adhesive tape.

<Comparative Example 4>

(Production of single-sided adhesive tape)

Except that the primer treatment layer 6 is not formed, everything else is the same as in Comparative Example 3, and a single-sided adhesive tape formed by the composition of the adhesive layer 5a/black printing layer2/bright color printing layer3/support 1b is obtained.

The adhesive tapes obtained in the above Example 2, Reference Example 1, Comparative Examples 3 and 4 were evaluated according to the following methods. The results are shown in Table 3.

(Adhesion to SUS under normal conditions and after heating)

According to JIS Z 0237 (2000), the adhesion to the SUS board was measured. However, the adhesive force after heating was heated in a heating furnace at 120°C for 2 hours, and after standing at room temperature for 2 hours, the adhesive force was measured under the conditions specified in JIS Z 0237 (2000).

(Residue)

The adhesion to SUS after heating is to confirm whether there is any residual glue when peeling off the adhesive tape (the state where part of the adhesive layer is attached to the adherend).

(Substrate adhesion)

First, as shown in FIG. 4(a), at the center of a test piece 10 (adhesive tape) having a size of 25×50 mm, a 2 mm cut mark is made with a cutter. Next, as shown in FIG. 4(b), the test piece 10 was split to 20 mm from the cut mark, and the length of the adhesive film 11 remaining unbroken was measured, and evaluation was performed according to the following criteria.

"○": The length of the adhesive film 11 is 2 mm or less.

"×": The length of the adhesive film 11 exceeds 2 mm.

(Retentivity)

According to JIS Z 0237 (2000), it is measured under the conditions of an adhesive area of 10×20 mm, a load of 200 g, a heating temperature of 150°C, and a heating time of 30 minutes.

<evaluation>

From the results shown in Table 3, it was found that the adhesive tape of Example 2 was excellent in all physical properties such as the adhesiveness of the base material. This phenomenon can be considered to be the use of the black printed layer 2 which has poor compatibility with silicone adhesives as the laminated base material A formed on the inside of the support 1a, and the primer treatment layer is provided on the surface of the support 1a Due to 6 reasons. On the other hand, the reference example 1 where the primer treatment layer 6 is not provided, the comparative example 3 where the primer treatment layer 6 is directly in contact with the black printing layer 2, and the comparison example where the black printing layer 2 is in direct contact with the silicone adhesive layer 5a In Comparative Example 4, the adhesion and retention of the substrate were poor, and residual glue was also generated. In addition, since Reference Example 1 has the same layer structure as Example 1, for example, the effect of the layer structure is excellent, such as the migration of components between the adhesive layer and the printed layer.

<Reference example 2~6>

(Preparation of Adhesive Composition)

With respect to 100 parts of a commercially available polyester adhesive (manufactured by Toyo-Morton Co., Ltd., trade name AD-76P1), 12.0 parts of an isocyanate-based curing agent (manufactured by Toyo-Morton Co., Ltd. trade name CAT-RT85) is blended , Diluted with 110 parts of toluene to obtain an adhesive composition (Reference Example 2). In addition, 10 parts of white ink (manufactured by Toyo Ink Co., Ltd., trade name E039PET63 white), 30 parts (reference example 4), and 50 parts (reference example) were added to 222 parts of the adhesive composition. 5) 100 parts (Reference Example 6), and then add an appropriate amount of toluene to obtain each adhesive composition with different white ink addition amounts.

(Production of laminated base material)

Except for using each adhesive composition with different addition amounts of white ink obtained as described above, the rest are the same as in Example 1, and the support 1a/black printing layer 2/adhesive A laminated base material with a total thickness of 23 μm formed by the composition of the adhesive layer 4/bright color printing layer 3/support 1b.

For the adhesive tapes obtained in Reference Examples 2 to 6, the average reflectance was measured according to the aforementioned measurement method. The results are shown in Table 4.

<evaluation>

According to the results shown in Table 4, the adhesive tape of the present invention can easily control the light reflectivity by coloring the adhesive layer into a bright color.

(Industrial availability)

The adhesive tape of the present invention is an adhesive tape with both light reflectivity and light-shielding functions. It is not prone to build-up substrate adhesion or pinhole formation due to peeling of the printed layer, and it is easy to adjust the physical properties such as adhesion and has excellent reworkability. , Can be easily applied to, for example, silicone adhesive layers, so it is more suitable for applications such as: mobile phones, touch panels, computers, car navigation, game consoles, TVs and other liquid crystal display devices used in liquid crystal display panels, and Fixing between backlight units.

1a‧‧‧Support

1b‧‧‧Support

2‧‧‧Black printing layer

3‧‧‧Bright color printing layer

4‧‧‧Adhesive layer

5a‧‧‧Adhesive layer

5b‧‧‧Adhesive layer

Claims (6)

An adhesive tape comprising: a laminated base material and an adhesive layer provided on at least one of the laminated base materials; characterized in that the laminated base material is a laminated body in which at least one black printing layer is laminated on a support , And a laminate with at least one bright-color printing layer laminated on a support, joined to each other on one side of the printed layer side with an adhesive layer interposed. Such as the adhesive tape of claim 1, wherein the supporting system resin film. Such as the adhesive tape of claim 1, wherein at least one of the adhesive layers contains a silicone-based adhesive. Such as the adhesive tape of claim 3, wherein the surface of the laminated base material provided with the adhesive layer containing the silicone adhesive is primed. Such as the adhesive tape of claim 1, wherein the adhesive layer is colored brightly. Such as the adhesive tape of claim 1, which is used for fixing between the liquid crystal display panel and the backlight unit.

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