TWI510589B - Double sided pressure sensitive adhesive tape and display device having a touch panel - Google Patents

Description

Double-sided adhesive tape and display device with touch panel

The present invention relates to a double-sided adhesive tape and a display device having the touch panel. Specifically, the present invention relates to a double-sided adhesive tape and a display device having the touch panel using the double-sided adhesive tape, which is a laminated body in which a specific property is present On both sides of the core material, an adhesive layer having a specific property is provided, and the tape is suitable for use in a case where a member in a mobile product such as a mobile phone or a touch panel is fixed, and the appropriateness of the step is applied. It is excellent in adhesiveness and water resistance, and has an unevenness adaptability in the case of waterproofing or the like in an action information terminal having a narrow frame edge provided around the display screen.

In an action information terminal device such as a mobile phone, a PHS, a music player, or the like, a double-sided adhesive tape is used for fixing various parts of the information display portion and the casing, the camera, and the key pad. In recent years, mobile information terminal devices having various functions have been developed, and for one of various functions, waterproof performance is required.

As a double-sided tape having water repellency, a double-sided adhesive tape having a foam base material and an adhesive layer has been developed (for example, refer to Patent Documents 1 and 2).

The double-sided adhesive tape for waterproofing described in Patent Documents 1 and 2 has a polyolefin-based foam base material and an acrylic pressure-sensitive adhesive. Since the substrate is foamed, the substrate and the adhesive are firmly bonded at the interface. Further, since the foam base material has a separate foam structure, even when one surface of the double-sided adhesive tape is wetted by water, the water does not permeate to the other surface and exhibits water repellency. Further, the foam base material is excellent in unevenness.

However, in the case of a very narrow tape having a width of 1 mm, in the double-sided tape for waterproofing using a foam, there is a risk of not sufficiently securing the bubble wall of the closed cells for controlling the penetration of water in the width direction. Waterproof. In addition, the size of the foam shape has a limit, and it is difficult to finely control its size.

In recent mobile phones, it has been demanded from the viewpoint of appearance and function that the type of display screen is increased, and in this case, the frame portion around the display screen is designed to be as narrow as possible. Although it is assumed that the double-sided tape used in the same manner is used in the form of a narrow frame edge having a width of 2 mm or less, it is difficult to use the double-sided tape for waterproofing described above because of the foam structure as explained above. It is difficult to apply the problem of a mobile phone having a large display screen because the width of the frame edge is narrowed. Further, even in the case of a narrow frame edge pattern, it is necessary to firmly fix the member. However, since the base material is foamed, there is a problem that the strength of the base material is low and the adhesion is difficult.

Prior art literature

Patent Document 1 Japanese Patent Laid-Open Publication No. 2009-108314

Patent Document 2 Japanese Patent Laid-Open Publication No. 2009-242541

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a double-sided adhesive tape which is a laminated body obtained by providing an adhesive layer on both faces of a core material, and is suitable for use, for example, in a mobile phone. In the case where the member of the mobile product such as a touch panel is fixed or the like, the gap is suitable for adhesion, adhesion, and water resistance, and the bumper is used for waterproofing or the like in the mobile information terminal having a narrow frame edge. Adaptability.

In order to achieve the above object, the inventors of the present invention conducted intensive studies, and as a result, the following findings were obtained.

As the core material, the core material is a film formed of a synthetic resin having specific properties, and preferably an olefin polymer such as an ethylene-methacrylic acid copolymer or an ethylene-vinyl acetate copolymer. The formed film can achieve the above object by a double-sided adhesive tape obtained by providing a laminate having an acrylic adhesive layer having specific properties on both surfaces.

The present invention has been completed in view of the above points.

(1) A double-sided adhesive tape formed of a laminated body having a core material and an adhesive layer disposed on both faces of the core material, wherein

(a) The 5% tensile stress of the above core material is in the range of 3 to 100 N, and the hardness (Gorefa) is 0.2 mN or less;

(b) the above two adhesive layers respectively comprise a (meth) acrylate copolymer and an adhesive-imparting resin, and are formed by thermally crosslinking an adhesive composition containing a crosslinking agent, wherein 100 parts by mass of the (meth) acrylate copolymer, and the adhesive resin is in the range of 1 to 60 parts by mass.

(2) The double-sided adhesive tape according to the above item (1), wherein the core material is a film formed using an olefin polymer having 60 to 100% by mass of an olefin monomer unit.

(3) The double-sided adhesive tape according to the above item (2), wherein the olefin polymer is an ethylene-methacrylic acid copolymer and/or an ethylene-vinyl acetate copolymer.

(4) The double-sided adhesive tape according to any one of the above (1) to (3) wherein the thickness of the core material is in the range of 2 to 400 μm, and the thicknesses of the two adhesive layers are respectively 2 ~80μm range.

The double-sided adhesive tape according to any one of the above aspects (1) to (4), wherein the double-sided adhesive tape has a shape of a frame shape of 0.1 to 2 mm width.

(6) The double-sided adhesive tape according to any one of the above (1) to (5), which is used for fixing inside the mobile information terminal device.

(7) The double-sided adhesive tape according to any one of the above (1) to (6), which is for waterproofing.

(8) A display device comprising a touch panel, wherein the frame is fixed by the double-sided adhesive tape according to any one of the above (1) to (7).

According to the present invention, there can be provided a double-sided adhesive tape and a display device with the touch panel using the double-sided adhesive tape, the double-sided adhesive tape being a laminated body in which the laminated body is composed of two faces of the core material It is obtained by providing an adhesive layer which is suitable for use in fixing a member in a mobile product such as a mobile phone or a touch panel, and the like, the adhesion of the step, the adhesion and the water resistance are excellent, and the tape is provided at the frame edge. The concave-convex adaptability in the case of waterproofing or the like in the narrow mobile phone information terminal.

First, the double-sided adhesive tape of the present invention will be described.

[double-sided adhesive tape]

The double-sided adhesive tape of the present invention is a laminate comprising a core material and an adhesive layer disposed on both faces thereof, wherein

(a) The 5% tensile stress of the above core material is in the range of 3 to 100 N, and the hardness (Gorefa) is 0.2 mN or less;

(b) the above two adhesive layers each comprise a (meth) acrylate copolymer and an adhesive-imparting resin, and are formed by thermally crosslinking an adhesive composition containing a crosslinking agent, wherein 100 parts by mass of the (meth) acrylate copolymer, and the adhesive resin is in the range of 1 to 60 parts by mass.

(Core)

In the double-sided adhesive tape of the present invention, it is required that the 5% tensile stress of the core material constituting the laminate is in the range of 3 to 100 N, and the hardness (Gorefa) is 0.2 mN or less.

Since the 5% tensile stress of the core material is in the range of 3 to 100 N, high surface bonding force is obtained, and excellent workability and narrow frame-like workability are maintained, and suitable flexibility is obtained, so that the unevenness is adapted. Excellent sex. The tensile stress is preferably in the range of 4 to 80 N, and particularly preferably in the range of 5 to 50 N.

On the other hand, since the softness (Gore method) of the core material is 0.2 mN or less and has a suitable softness, the unevenness is excellent.

Although the thickness of the core material is not particularly limited, it is preferably in the range of 2 to 400 μm, more preferably in the range of 10 to 200 μm, and particularly preferably in the range of 50 to 150 μm in consideration of the processing type and thickness reduction. . When the thickness is 2 μm or more, the workability of the core material itself, the shear processing suitability of the double-sided tape, the press workability and the strength can be ensured, and the flexibility can be ensured by making the thickness 400 μm or less.

Moreover, the 5% tensile stress of the core material and the softness of the core material (Gore method) are values measured by the following method.

<Method for Measuring 5% Tensile Stress of Core Material>

The core material was cut to a size of 15 mm in width and 50 mm in length to prepare a sample for measurement, and 10 mm of both ends of the sample for measurement was set by a tensile compression tester, and the measurement was performed at a tensile speed of 200 mm/min. Stress at a measurement site having a width of 15 mm and a length of 30 mm.

<Measurement Method of Softness of Core Material (Gore Method)>

The core material was cut in a size of 38 mm in length and 25 mm in width to prepare a sample for measurement, and the softness was measured in accordance with "JIS L 1085 (1998) 6.10.3 Gore method" using a GRAY type softness tester.

The core material constituting the laminated body of the double-sided adhesive tape of the present invention is not particularly limited as long as it satisfies the above properties, and can be appropriately selected and used from a synthetic resin film known in the past.

The synthetic resin film having the above properties constituting the core material is, for example, contained in an amount of 60 to 100% by mass, preferably 70 to 97% by mass, more preferably 80 to 94% by mass. A film formed of an olefin polymer of a monomer unit.

Specific examples of such an olefin polymer include an ethylene-methacrylic acid copolymer, an ethylene-vinyl acetate copolymer, and the like. These olefin polymers may be used singly or in combination of two or more kinds.

In order to improve the adhesion of the adhesive layer provided on the both surfaces of the film, the synthetic resin film constituting the core material may be oxidized or embossed, or the like, on both sides as needed. Surface treatment or primer treatment. Examples of the oxidation method include, for example, a corona discharge treatment, a plasma discharge treatment, a chromic acid treatment (wet), a hot air treatment, an ozone ‧ an ultraviolet ray treatment, and the like. Solvent treatment method, etc. These surface treatment methods are appropriately selected depending on the type of the synthetic resin film, but it is preferable to use a corona discharge treatment method from the viewpoints of effects and workability.

Further, the color of the core material is not particularly limited, and it may be colorless or colored in an appropriate color.

Further, it is preferred that the core material is not a foam structure. In the double-sided tape for waterproofing using a core material having a foam structure, it is impossible to sufficiently ensure the bubble walls of the closed cells which control the penetration of water with respect to the width direction.

(adhesive layer)

In the double-sided tape of the present invention, the two adhesive layers provided on both surfaces of the synthetic resin film constituting the core material respectively contain a (meth) acrylate copolymer and a resin for imparting adhesion, and The adhesive composition containing a crosslinking agent is formed by thermal crosslinking, and the adhesive resin is contained in an amount of from 1 to 60 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer.

In the double-sided adhesive tape of the present invention, if the respective properties of the two adhesive layers satisfy the above conditions, they may have the same composition and properties, or may have different compositions and properties, but from the viewpoint of productivity In other words, it is preferred to have the same composition and properties.

<(Meth)acrylate copolymer>

The (meth) acrylate copolymer contained as a main component is not particularly limited in the acrylic pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer, and is conventionally used as a main component of a conventional acrylic pressure-sensitive adhesive ( In the methyl acrylate copolymer, any type can be appropriately selected and used. Examples of the (meth) acrylate copolymer include, for example, a (meth) acrylate having an alkyl group of an ester moiety in a range of from 1 to 20; a monomer including a functional group having an active hydrogen; Copolymers of other monomers which are required to be used. Further, (meth) acrylate means methacrylate and/or acrylate.

Here, examples of the (meth) acrylate having an alkyl group in the ester moiety in the range of 1 to 20 include methyl (meth)acrylate and ethyl (meth)acrylate. Base) propyl acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, amyl (meth) acrylate, hexyl (meth) acrylate, (A) Base) cyclohexyl acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, lauric (meth) acrylate Ester, tetradecyl (meth)acrylate, cetyl (meth)acrylate, octadecyl (meth)acrylate, and the like. These may be used singly or in combination of two or more kinds.

On the other hand, examples of the monomer including a functional group having an active hydrogen include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate. a (meth)acrylic acid hydroxyalkyl ester such as ester, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; (meth)acrylic acid (meth)acrylic acid such as monomethylaminoethyl ester, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, monoethylaminopropyl (meth)acrylate An alkylaminoalkyl ester; an ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid or citraconic acid. These may be used singly or in combination of two or more kinds.

Moreover, examples of other monomers used as needed include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene, and isobutylene; and vinyl chloride, vinylidene chloride, and the like. Halogenated olefins; styrene monomers such as styrene and α-methylstyrene; diene monomers such as butadiene, isoprene, and chloroprene; acrylonitrile, methacrylonitrile, etc. Nitrile monomers; acrylamides such as acrylamide, N-methyl acrylamide, N,N-dimethyl decylamine, and the like. These may be used singly or in combination of two or more kinds.

The copolymerization form of the above (meth) acrylate copolymer used as a main component in the propylene-based pressure-sensitive adhesive composition is not particularly limited, and may be any of random, block, and graft copolymers. Further, the molecular weight, the weight average molecular weight is preferably in the range of 300,000 or more, more preferably in the range of 5 to 2.5 million. When the weight average molecular weight is less than 300,000, the adhesion to the bonded body and the durability adhesiveness may be insufficient. The weight average molecular weight is preferably in the range of 60 to 1.8 million in consideration of adhesiveness, durability, and the like.

Further, the above weight average molecular weight is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

Further, in the (meth) acrylate copolymer, the content of the monomer unit having a functional group having active hydrogen is preferably in the range of 0.01 to 10% by mass. When the content is less than 0.01% by mass, the crosslinking point is too small, the crosslinking is insufficient, and the adhesion of the adhesive is likely to be broken. When the content is more than 10% by mass, the viscosity is increased and the coating suitability is lowered. A more preferable content of the monomer unit including a functional group having the active hydrogen is in the range of 0.05 to 6.0% by mass, particularly preferably in the range of 0.2 to 5.0% by mass.

<resin imparting adhesive>

In the double-sided adhesive tape of the present invention, in order to improve the adhesion to the object, the adhesive for forming the adhesive layer is required to have sufficient unevenness, adhesion, and workability. A resin that imparts adhesion is used. The resin to which the adhesion is imparted is not particularly limited, and can be appropriately selected from resins conventionally used as a resin for imparting adhesion to conventional adhesives. Examples of the tackifying resin include rosin-based resins (raw rosin, water-added rosin, polymerized rosin, and rosin ester), xylene resin, terpene phenol resin, petroleum resin, coumarone-indene resin, and terpene resin. , styrene resin, etc.

Specific examples of the products on the market include PINECRYSTAL KE-359 (produced by Arakawa Chemical Industries Co., Ltd.), SUPER ESTER A-75 (produced by Arakawa Chemical Industries, Ltd.), SUPER ESTER A-100 (produced by Arakawa Chemical Industries, Ltd.), and SUPER ESTER. Aromatic esters of A-125 (produced by Arakawa Chemical Industries Co., Ltd.), PENSELD 125 (produced by Arakawa Chemical Industries, Ltd.), PENSELD 160 (produced by Arakawa Chemical Industries, Ltd.), and polymerized rosin esters such as Rikatack PCJ (manufactured by Physicochemical FINE TECH); NIKANOL HP -100 (manufactured by Mitsubishi Gas Chemical Co., Ltd.), NIKANOL HP-150 (manufactured by Mitsubishi Gas Chemical Co., Ltd.), xylene resin such as NIKANOL H-80, YS POLYSTER T-115 (manufactured by YASUHARA CHEMICAL Co., Ltd.), and MYTECH G125 (YASUHARA CHEMICAL Co., Ltd.) Terpene phenol resin such as production; petroleum resin such as FTR-6120 (manufactured by Mitsui Chemicals, Inc.) and FTR-6100 (manufactured by Mitsui Chemicals Co., Ltd.).

These adhesively-adhering resins may be used singly or in combination of two or more kinds. However, among these resins, rosin esters are preferred from the viewpoint of imparting adhesiveness and the like.

In the adhesive composition, the resin to be adhered is required to be in the range of 1 to 60 parts by mass, preferably 3 to 50 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer. Inside, it is particularly good in the range of 5 to 40 parts by mass. When the content of the resin for imparting adhesion is within the above range, the adhesion to the object to be joined is good.

<Crosslinking agent>

The crosslinking agent to be contained in the acrylic pressure-sensitive adhesive composition is not particularly limited, and any of the compositions conventionally used as a crosslinking agent in the conventional acrylic pressure-sensitive adhesive composition can be appropriately selected and used. Types of. Examples of such a crosslinking agent include a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, an aziridine compound, a metal chelate compound, and a metal alkoxide ( Alkoxide, a metal salt or the like is preferably a polyisocyanate compound.

Here, examples of the polyisocyanate compound include an aromatic polyisocyanate such as tolylene diisocyanate, diphenylmethane diisocyanate or xylylene diisocyanate, and an aliphatic polyisocyanate such as hexamethylene diisocyanate. An alicyclic polyisocyanate such as phorone diisocyanate or hydrogenated diphenylmethane diisocyanate, and a biuret or isocyanurate thereof; and further, ethylene glycol, propylene glycol, and neopentyl An adduct of a reactant of a low molecular weight active hydrogen-containing compound such as an alcohol, trimethylolpropane or castor oil.

In the present invention, the crosslinking agent may be used singly or in combination of two or more. Further, the amount thereof is also dependent on the kind of the crosslinking agent, and is usually selected in the range of 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass of the solid content of the (meth) acrylate copolymer. Selected within the scope.

If necessary, various additives such as a decane coupling agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a softener, and a filler may be contained in the acrylic adhesive composition within a range not impairing the object of the present invention. Agents, colorants, etc.

In the double-sided tape of the present invention, the thickness of the two adhesive layers formed by using the acrylic adhesive composition is not limited, but is preferably in the range of 2 to 80 μm, particularly preferably 5 to 60 μm. Within the scope. When the thickness is 2 μm or more, the adhesion between the unevenness and the adherend is excellent, and the thickness is 80 μm or less, and the workability is excellent.

<release sheet>

In the double-sided adhesive tape of the present invention, it is preferable to have a type of a release sheet stacked from the viewpoint of convenience in transportation or use. The double-sided adhesive tape of the present invention may be in the form of being sandwiched by two release sheets, or may be stacked on one side with one release sheet having mold release property, and the form of winding in this state .

The release sheet used in the double-sided adhesive tape of the present invention may be various release sheets, but as a representative embodiment, it is composed of a release sheet substrate having release properties on the surface. Examples of the substrate for a release sheet include polyethylene terephthalate, polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, and vinyl chloride copolymer. Polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, ethylene (meth)acrylic copolymer, polystyrene, polycarbonate, fluororesin, low density polyethylene, A resin film such as a linear low-density polyethylene or a triethyl fluorenyl cellulose; a high-grade paper, a coated paper, a cellophane, a laminated paper, or the like. Among these, a film of polyethylene terephthalate which is inexpensive and tough is preferable. The thickness of the substrate for release sheet is preferably in the range of 5 μm to 300 μm, more preferably in the range of 10 μm to 200 μm.

In order to impart release property to the surface of the release sheet substrate, a release agent such as an fluorenone resin, a fluorine resin, or a long-chain alkyl resin is applied to the surface thereof. Among these, an anthrone-based resin which is low in cost and which has stable properties is preferable. The thickness of the release agent layer is preferably in the range of 0.05 μm to 2.0 μm, more preferably in the range of 0.1 μm to 1.5 μm.

In the manufacture of the double-sided adhesive tape of the present invention, it is preferred to make the release force of the corresponding release sheet different. If the release force is different, the risk of the adhesive layer floating from the side of the release sheet and the release sheet accompanying both sides, the adhesive layer being stretched and deformed may be prevented when only the light release sheet side is peeled off. . In addition, in the case of a double-sided adhesive tape which is wound on one side and has a release property on both sides, the release force of the inner and outer surfaces of the release sheet is different, Get the same effect.

(Manufacture of double-sided adhesive tape)

Next, a method of manufacturing the double-sided adhesive tape of the present invention will be described.

First, in the above-mentioned acrylic pressure-sensitive adhesive composition, a solvent is added as needed, and the viscosity suitable for coating is adjusted to prepare a coating liquid.

Next, on the release-treated surface of the light release sheet (or the release sheet), the film thickness after drying is in the range of 2 to 80 μm, preferably 5 to 60 μm, for example, by Coating the coating liquid by a conventionally known coating method such as a bar coating method, a reverse roll coating method, a doctor blade coating method, a roll blade coating method, a gravure coating method, a gas knife coating method, or a blade coating method, The film is heated and dried at a temperature of 80 to 120 ° C for several tens of seconds to several minutes to thermally crosslink the adhesive composition layer, and then the core material is bonded thereto to form a single-sided adhesive film.

Thereafter, on the release-treated surface of the release sheet (or the light release sheet), the film thickness after drying is in the range of 2 to 80 μm, preferably in the range of 5 to 60 μm, and is the same as before. The coating liquid is applied, heat-dried, thermally crosslinked, and then bonded to the core surface of the single-sided adhesive film to obtain the double-sided adhesive tape of the present invention.

With respect to the double-sided adhesive tape of the present invention obtained as described above, the surface joint strength measured by the measurement conditions described later is preferably 120 N or more, and particularly preferably 170 N or more. By setting the surface bonding strength to 120 N or more, it is possible to obtain excellent adhesion when the member is used in a fixed manner.

The use of the double-sided adhesive tape will be described below.

[Use of double-sided adhesive tape]

The double-sided adhesive tape of the present invention is a laminate in which an acrylic adhesive layer having a specific property is provided on both faces of a core material having a specific property, and the tape is suitable for use, for example, in action When the components in the mobile product such as a telephone or a touch panel are fixed, the gap is suitable for adhesion, the adhesion and the water resistance are excellent, and the double-sided adhesive tape for waterproofing is used in the mobile information terminal having a narrow frame edge. .

In the double-sided adhesive tape of the present invention, the core material adopts a synthetic resin film having specific properties, thereby having no pores and excellent water resistance, and the width is in the range of 0.1 to 2 mm, particularly in the range of 0.2 to 1 mm. Used for waterproofing. That is, in the action information terminal of the narrow frame type, it can be used as a double-sided adhesive tape for waterproofing.

The double-sided adhesive tape of the present invention may be in the form of a frame-like shape in which the release sheets are adhered on both faces.

Further, in the double-sided adhesive tape of the present invention, any or all of the core layer and the adhesive layer may be black. In particular, in the case where the double-sided adhesive tape is in the form of a frame, it is preferably black.

The black treatment of the core material and the adhesive layer can be carried out by mixing carbon black or black pigments, dyes, or the like.

The present invention also provides a display device including a touch panel, characterized in that the frame is fixed by the double-sided adhesive tape of the present invention described above.

Example

The present invention will be more specifically described below based on the examples, but the present invention is not limited to these examples.

Further, each characteristic of the double-sided adhesive tape obtained in each example was determined by the following method.

(1) Thickness of core material and adhesive layer

The thickness of the core material and the adhesive layer obtained in each example was measured by a constant pressure thickness measuring device (manufactured by TECLOCK, product name "PG-02") in accordance with JIS K 7130.

(2) 5% tensile stress of the core material

The core material obtained in each example was cut to a size of 15 mm in width and 50 mm in length to prepare a sample for measurement. Then, a tensile tester (manufactured by Shimadzu Corporation, model "AG-IS") was used, and both ends of the sample for measurement were set to 10 mm, and the measurement was carried out at a tensile speed of 200 mm/min and a width of 15 mm according to a temperature of 23 ° C. The measurement portion having a length of 30 mm was a stress at 5% stretching.

(3) Softness of core material (Gorefa)

The core material was cut according to the length of 38 mm and the width of 25 mm, and a sample for measurement was produced. The product was produced by Toyo Seiki Co., Ltd., product name 'Gore Softness Tester', according to JIS L 1085 (1998) 6.10.3. Gorefa", the measurement was carried out.

(4) Water resistance test

The evaluation was carried out in accordance with JIS C 0920 (2003) 14.2.7, Test of the second characteristic number 7 of the temporary diving state with a depth of 0.15 to 1 m. 1 is a plan view of a sample for measurement, FIG. 2 is a cross-sectional view taken along line A-A in the plan view, and FIG. 3 is a cross-sectional view taken along line B-B in the plan view. At the time of the test, the following measurement samples were prepared, in which two transparent acrylate plates 1a and 1b having a longitudinal direction of 70 mm, a lateral direction of 50 mm, and a thickness of 2 mm were frame-like in shape of a longitudinal direction of 60 mm × a width of 40 mm and a width of 1 mm. The laminate member 2 is laminated. The one acrylate plate 1a of the sample for measurement has a step of a black print 3 having a cross shape of a height of 10 μm and a width of 5 mm. The other acrylate plate was made of a smooth acrylate plate 1b having no step (see Figs. 1 to 3). After the test sample was prepared, the measurement sample was allowed to sink to a depth of 1 m and allowed to stand for 30 minutes. Then, the presence or absence of water intrusion in the sample piece was confirmed by visual observation, and the following criteria were used. To evaluate water repellency.

○: There is no intrusion of water inside the sample piece (qualified)

×: Intrusion of water inside the sample piece (failed)

(5) Surface bonding force

Equipped with acrylate board (produced by Mitsubishi RAYON Co., Ltd., product name "ACRYLITE L001", 70 × 50 × 2mm), fully coated with UV-curable ink on one side (produced by Imperial Ink Company, product name "POS-911 Ink") ). Next, a plate having a hole having a diameter of 2 cm was inserted in the middle of a stainless steel plate (manufactured by PALTEK, product name "SUS304 #600", 150 x 70 x 0.5 mm, single side #600 grinding).

Next, the ink layer of the acrylate plate and the #600 polished surface of the stainless steel plate were bonded to each other using a double-sided tape processed in a frame shape of 60 mm in the longitudinal direction, 40 mm in the lateral direction, and 2 mm in width. Then, at a speed of 10 mm/min, in a universal tensile compression tester (manufactured by INSTRON, product name "INSTRON 5581"), the clamp is fixed on the measuring portion of the universal tensile compression tester. 10 mm of a cube made of a polycarbonate resin is fixed to the bottom surface of the measuring portion by an adhesive tape, and the contact portion of the measuring portion and the acrylate plate is a square of 10 mm × 10 mm), and a hole is pressed in the surface direction. The exposed portion of the ink-coated surface of the acrylate plate was used to measure the stress (peak value of the load) when the double-faced tape was peeled off.

4 is an explanatory view showing a method of measuring a surface joining force. In Fig. 4, Fig. 4(a) is a cross-sectional view, Fig. 4(b) is a perspective view, reference numeral 10 is a double-sided adhesive tape, reference numeral 11 denotes a stainless steel plate having a hole, and reference numeral 12 denotes an ink layer on the double-sided adhesive tape side. The acrylate plate of 14, the numeral 13 indicates the press-in direction.

(6) Strict width processability

When the NT cutter is used for cutting in a shape of a width of 1 mm and a length of 50 mm, the microgauge is used to confirm that the sample width is 1 mm ± 0.2 mm, and if it is within the range of 1 mm ± 0.2 mm, it is expressed as ○, if it is outside the range, it is represented as ×.

Preparation Example 1 Preparation of Coating Liquid 1 for Adhesive Formation

Acrylate copolymer with butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), acrylic acid (AAc) as monomer component (2EHA/BA/AAc mass ratio = 80/19/1, weight average) 5 parts by mass of a resin (available under the name "PINECRYSTAL KE-359", manufactured by Arakawa Chemical Industries Co., Ltd.), and an isocyanate crosslinking agent (Toyo Ink Co., Ltd.) Production, product name "BHS-8515", solid content: 37.5 mass%) 3.6 parts by mass (2.45 parts by mass based on 100 parts by mass of the solid content of the acrylate copolymer), and a coating liquid 1 for forming an adhesive was prepared.

Preparation Example 2 Preparation of Coating Liquid 2 for Adhesive Formation

Acrylate copolymer with butyl acrylate (BA), acrylic acid (AAc) and 2-hydroxyethyl acrylate (HEA) as monomer components (BA/AAc/HEA mass ratio = 98/1.5/0.5, weight average molecular weight 20 parts by weight of a solid resin (40% by mass) of a resin (available under the name "PINECRYSTAL KE-359" by Arakawa Chemical Industries Co., Ltd.) and an isocyanate crosslinking agent (produced by Toyo Ink Co., Ltd.) In the product name "BHS-8515", the solid content (37.5 mass%) was 1 part by mass (0.94 parts by mass based on 100 parts by mass of the solid component of the acrylate copolymer), and the coating liquid 2 for forming an adhesive was prepared.

Preparation Example 3 Preparation of Coating Liquid 3 for Adhesive Formation

An acrylate copolymer containing butyl acrylate (BA), methyl acrylate (MA), and acrylic acid (AAc) as a monomer component (BA/MA/AAc mass ratio = 77/20/3, weight average molecular weight of 800,000 In an amount of 28 parts by mass of the copolymer and the solid component, 100 parts by mass of an isocyanate-based crosslinking agent (produced by Toyo Ink Co., Ltd., product name "BHS-8515", solid content: 37.5 mass%) 1.8 parts by mass (relative to acrylate copolymer) 1.8 parts by mass of the solid component (2.41 parts by mass) and 1.8 parts by mass of the aluminum chelate crosslinking agent (M-5A, solid component: 4.95 parts by mass) (relative to the solid content of the acrylate copolymer 100 mass) In the amount of 0.32 parts by mass, the coating liquid 3 for forming an adhesive was prepared.

Preparation Example 4 Modulation of Coating Liquid 4 for Adhesive Formation

Acrylate copolymer with butyl acrylate (BA), methyl acrylate (MA) and 4-hydroxybutyl acrylate (4HBA) as monomer components (BA/MA/4HBA mass ratio = 79/20/1, weight In an amount of 100 parts by mass of a copolymer having an average molecular weight of 900,000 and a solid content of 30% by mass, 0.05 parts by mass of a mixture of isocyanate-based cross-linking agents (product name "TD-75", solid content: 75 mass%) The 100 parts by mass of the solid content of the acrylate copolymer was 0.13 parts by mass, and the coating liquid 4 for forming an adhesive was prepared.

Example 1

A film of an ethylene-methacrylic acid copolymer (manufactured by Mitsui ‧DU PONT POLYCHEMICALS Co., Ltd., product name "N0903HC", olefin monomer unit 91% by mass) was produced in a thickness of 100 μm, and corona treatment was performed on both surfaces to obtain a core material. membrane. Then, a coating liquid for applying an adhesive is applied by a doctor blade coater at a thickness of 50 μm after drying on a release-treated surface of a light release sheet (manufactured by LINTEC Co., Ltd., trade name "SP-PET381031"). 1. Heat and dry at 100 ° C for about 2 minutes to carry out thermal crosslinking. Then, the above core film was laminated on the adhesive layer to obtain a single-sided adhesive tape.

Then, a release coating surface of a release sheet (manufactured by LINTEC Co., Ltd., trade name "SP-PET3811") was coated with an applicator according to a thickness of 50 μm after drying. The liquid 1 was dried by heating at 100 ° C for about 2 minutes to carry out thermal crosslinking. Then, it was bonded to the surface of the core material film of the above-mentioned single-sided adhesive film to prepare a double-sided adhesive tape.

Example 2

In the same manner as in Example 1, except that the coating liquid 1 for forming an adhesive was used instead of the coating liquid 1 for forming an adhesive, the double-sided adhesive tape was produced.

Example 3

In the same manner as in Example 1, except that the core material film was a film which was subjected to corona treatment on both surfaces of a polyethylene film (manufactured by TAMAPOLY Co., product name "A-1", thickness: 100 μm). The way is to make a double-sided adhesive tape. Further, Example 3 is a reference example.

Example 4

With respect to Example 1, except that the core material film was formed to have a thickness of 100 μm, an ethylene-vinyl acetate copolymer (produced by Sumitomo Chemical Co., Ltd., product name "EVATATE D2045", olefin monomer unit: 95% by mass) was formed. A double-sided adhesive tape was produced in the same manner as in Example 1 except that the film was subjected to corona treatment on both surfaces.

Comparative example 1

In the same manner as in Example 1, except that the coating liquid 1 for forming an adhesive was used instead of the coating liquid 1 for forming an adhesive, a double-sided adhesive tape was produced.

Comparative example 2

In the same manner as in Example 1, except that the coating liquid 1 for forming an adhesive was used instead of the coating liquid 1 for forming an adhesive, a double-sided adhesive tape was produced.

Comparative example 3

In the same manner as in Example 1, except that the core material film was a black polyolefin foam (manufactured by Sekisui Chemical Co., Ltd., trade name "BO LA LA") having a thickness of 100 μm, a double-sided adhesive was produced. band.

Comparative example 4

A double-sided fabric was produced in the same manner as in Example 1 except that a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., product name "Lumirror T-60") having a thickness of 100 μm was used. Adhesive tape.

Comparative Example 5

The coating agent for forming an adhesive is applied to the release-treated surface of the release sheet (LINTEC, trade name "SP-PET3811") by a blade applicator so as to have a thickness of 50 μm after drying. 1. Heat and dry at 120 ° C for 2 minutes to carry out thermal crosslinking, and then apply a light release sheet (manufactured by LINTEC, trade name "SP-PET381031"). Next, the three obtained adhesives were bonded together to form a double-sided adhesive tape. The middle layer of the three was used as a core material, and the 5% tensile stress and softness of Comparative Example 5 were measured.

Table 1 shows the evaluation results of the respective characteristics of the double-sided adhesive tape produced in accordance with the above Examples 1 to 4 and Comparative Examples 1 to 5.

Industrial use possibilities

The double-sided adhesive tape of the present invention is a laminate formed by providing an adhesive layer on both surfaces of a core material, and the tape is suitable for use in a case where a member in a mobile product such as a mobile phone or a touch panel is fixed, or the like. The step of the tape is excellent in suitability, adhesion, and water resistance, and is used for waterproofing or the like in an action information terminal having a narrow frame edge.

1a. . . Transparent acrylate board

1b. . . Transparent acrylate board

2. . . Frame-like laminated member

3. . . Cross-shaped black printing

10. . . Double-sided adhesive tape

11. . . Acrylate board with holes

12. . . Acrylate board with ink layer on the side of the double-sided adhesive tape

13. . . Pressing direction

14. . . Ink layer

1 is a plan view of a sample for measurement used in a waterproof evaluation test of a double-sided adhesive tape;

Figure 2 is a cross-sectional view taken along line A-A of Figure 1;

Figure 3 is a cross-sectional view taken along line B-B of Figure 1;

4(a) and 4(b) are explanatory views showing a method of measuring the surface joining force.

Claims (8)

A double-sided adhesive tape comprising a laminated body having a core material and an adhesive layer disposed on both faces of the core material, wherein (a) the core material has a 5% tensile stress of 3 Within the range of ~100N, and the hardness of the Gore method is below 0.2 mN; (b) the above two adhesive layers respectively comprise a (meth) acrylate copolymer and an adhesive-imparting resin, and The adhesive composition of the joint agent is formed by thermal crosslinking, wherein the adhesive material is contained in an amount of from 1 to 60 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer, and the core material is A film formed using an olefin polymer, which is an ethylene-methacrylic acid copolymer and/or an ethylene-vinyl acetate copolymer. The double-sided adhesive tape of claim 1, wherein the olefin polymer has 60 to 100% by mass of an olefin monomer unit. The double-sided adhesive tape of claim 1 or 2, wherein the thickness of the core material is in the range of 2 to 400 μm, and the thickness of the two adhesive layers is in the range of 2 to 80 μm, respectively. A double-sided adhesive tape according to claim 1 or 2, which has a shape which is punched in a frame shape of 0.1 to 2 mm width. A double-sided adhesive tape according to the third aspect of the patent application, wherein the double-sided adhesive tape has a shape of a frame shape of 0.1 to 2 mm width. For example, the double-sided adhesive tape of claim 1 or 2 is used for fixing the inside of the mobile information terminal device. A double-sided adhesive tape as claimed in claim 1 or 2, which is used for waterproofing. A display device having a touch panel, which is fixed to the frame by a double-sided adhesive tape according to any one of claims 1 to 7.