JP6104500B2 - Double-sided adhesive tape - Google Patents

Description

  The present invention relates to a double-sided pressure-sensitive adhesive tape, and more particularly to a thin double-sided pressure-sensitive adhesive tape or sheet that is suitably used in a joint portion of a casing or component of a portable electronic device.

  The adhesive tape has excellent workability and is used as a bonding means with high adhesion reliability in parts fixing applications and the like in various industrial fields such as OA equipment and home appliances. These OA devices have been reduced in size and thickness in parallel with various advanced functions, such as personal computers, digital video cameras, electronic notebooks, mobile phones, PHS, smartphones, game machines, electronic books, etc. In particular, there is a high demand for downsizing and thinning of portable electronic terminals. In such portable electronic terminals and the like, it is required to reduce the thickness of the main component parts and the adhesive tape used for fixing them.

  For example, a double-sided adhesive tape or sheet having pressure-sensitive adhesive layers on both sides of the support, the total thickness including the thickness of the support and two pressure-sensitive adhesive layers formed on both sides of the support being 3 μm or more And the double-sided adhesive tape or sheet | seat which is less than 30 micrometers and whose breaking strength is 2-26MPa / 10mm width is disclosed (patent document 1). Further, for example, a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive on both surfaces of the core material, the total thickness of the core material and the pressure-sensitive adhesive layer on both surfaces is 30 μm or less, A double-sided pressure-sensitive adhesive tape having a thickness of 2 to 10 μm is disclosed (Patent Document 2).

  These pressure-sensitive adhesive tapes or sheets have a very thin total thickness, thereby achieving clearance suitability for portable terminal devices that are highly demanded to be thin. However, since such a thin adhesive tape tends to wrinkle during production, wrinkles are suppressed by a production method including a step of adjusting the tension applied to the support to be as low as possible, and the productivity is extremely low. It was a thing. In addition, in thin tapes, a certain level of strength is required for the support in order to prevent the support from being cut out at the time of production, cutting during use, and cutting during use, but a resin film is used as the support. Since the film is stretched when it is thin and has high strength, heat shrinkage may occur in a high temperature environment.

JP 2005-105212 A JP 2007-169327 A

  Under such circumstances, the present invention was made for the purpose of providing a thin double-sided adhesive tape excellent in productivity and heat resistance, which is used for a joint portion of a casing or component of a portable electronic device. It is.

  As a result of intensive studies to achieve the above object, the present inventors have found that this object can be achieved by using a core material having a specific thickness, frictional resistance, and heat shrinkage rate, thereby completing the present invention. It came to do.

  That is, the present invention is a double-sided pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on both sides of a support made of a resin film, the total thickness is 2 to 10 μm, the thickness of the support is 1 to 3 μm, and the heat shrinkage rate Is a double-sided pressure-sensitive adhesive tape having a dynamic friction coefficient of 0.20 to 0.28.

  ADVANTAGE OF THE INVENTION According to this invention, the double-sided adhesive tape excellent in productivity and heat resistance used for the junction part of the housing | casing of portable electronic devices or components can be provided.

It is the schematic which shows an example of the double-sided adhesive tape of this invention. It is a schematic process drawing which shows an example of the method of manufacturing the double-sided adhesive tape of this invention. It is a schematic process drawing which shows an example of the method of manufacturing the double-sided adhesive tape of this invention. It is the schematic of the dynamic friction coefficient measuring method.

(Double-sided adhesive tape)
As shown in FIG. 1, the double-sided pressure-sensitive adhesive tape of the present invention is a double-sided pressure-sensitive adhesive tape with a base material having a pressure-sensitive adhesive layer on both sides of the support, and the support and the two formed on both sides of the support The total thickness including the thickness with the pressure-sensitive adhesive layer is 2 μm to 10 μm. As described above, the pressure-sensitive adhesive tape of the present invention is very thin and can be suitably used in the case of an electronic device having a small space, particularly a portable electronic device and a joint part. Moreover, since it has a base material, it is excellent in workability even when the adhesive tape is continuously punched.

  FIG. 1 is a schematic view showing an example of the double-sided pressure-sensitive adhesive tape of the present invention. In the double-sided pressure-sensitive adhesive tape of FIG. 1, 1 is a support, 2-3 is an adhesive layer, and 4-5 are release liners. The double-sided pressure-sensitive adhesive tape has a structure in which pressure-sensitive adhesive layers 2 and 3 are formed on each surface of the support 1, and the pressure-sensitive adhesive layers 2 and 3 are protected by release liners 4 and 5, respectively. Moreover, the said double-sided adhesive tape can also be made into the form wound so that it might overlap | superpose so that the release liners 4 and 5 might contact, and it might roll.

  Although it will not restrict | limit especially if it is 2 micrometers-10 micrometers as total thickness (tape thickness) of the double-sided adhesive tape of this invention, Preferably they are 3 micrometers-7 micrometers, More preferably, they are 3 micrometers-5 micrometers. Here, the total thickness of the double-sided pressure-sensitive adhesive tape refers to the thickness used for attachment excluding the release liner, that is, the thickness from one adhesive layer surface to the other adhesive layer surface.

  The adhesive strength of the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited, but is preferably 0.5 N / 20 mm to 12 N / 20 mm. More preferably, it is 1-8N / 20mm. By setting it as the above range, it is easy to achieve both peeling at the time of adhesion and ease of peeling at the time of rework. The adhesive strength is measured according to JISZ0237. Specifically, an adhesive tape lined with PET 25 μm was bonded to a stainless steel plate (BA plate), pressed once with a 2 kg roller, left for 1 hour under conditions of 23 ° C. and 50% RH, and 300 mm / 180 ° in the 180 ° direction. The peel adhesion is measured at a rate of min.

  Moreover, although the shift | offset | difference distance of the holding force of the double-sided adhesive tape of this invention is not restrict | limited in particular, 2 mm or less is preferable, More preferably, it is 0.5 mm or less, More preferably, it is 0.1 mm or less. When the shift distance of the holding force is in the above range, there is sufficient cohesive force even when used at a high temperature, and it is possible to suppress the peeling or contraction of the component or the core material due to the repulsive force. Holding power is measured according to JISZ0237. Specifically, an adhesive tape lined with 50 μm aluminum foil is bonded to a stainless steel plate (hairline), pressed once with a 2 kg roller, and left at 23 ° C. and 50% RH for 1 hour. Further, a load of 100 g is applied in the vertical direction at 100 ° C., and the deviation distance after 24 hours is measured with a caliper.

  The breaking strength of the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited, but is preferably 30 MPa to 200 MPa, and more preferably 40 MPa to 120 MPa. The breaking strength can be measured by the following method. Cut the double-sided adhesive tape to 10mm width, make a test piece (10mm width) with marks on the surface at intervals of 50mm, use a tensile tester, room temperature (23 ° C) and 65% RH condition Below, the load (stress) at the time when the test piece was pulled and the test piece broke (at least when a crack occurred from a part) under the conditions of 50 mm of the test piece gripping distance (distance between chucks) and a pulling speed of 200 mm / min. And the load is taken as the breaking strength (MPa).

(Support)
The thickness of the support is 1 μm to 3 μm. Preferably they are 1.5 micrometers-2.5 micrometers. By setting it as the thickness of the said range, necessary and sufficient heat resistance and adhesiveness can be expressed, although it is thin.

  The dynamic friction coefficient of the support is 0.20 to 0.28. More preferably, it is 0.22-0.26. By being in the said range, moderate slipperiness exists in a support body, even if it is a thin film, it is hard to wrinkle and it is excellent in productivity of an adhesive tape. The dynamic friction coefficient of the support is measured by the following method.

(Dynamic friction coefficient of support)
According to JISK7125, the friction coefficient between the SUS mirror surface and the film surface is measured. As shown in FIG. 4, a film 22 backed by a single-sided adhesive tape “PET50SER made by DIC” 21 is applied and fixed so that a 63 mm × 63 mm slip piece (weight: 1.96 N) 23 and the single-sided adhesive tape 21 are in contact with each other. . Next, the film 22 fixed to the sliding piece was placed so as to contact the SUS mirror surface 25, and the sliding piece 23 was pulled and measured by a load cell 26 at 100 mm / min. The dynamic friction coefficient is calculated by the following equation.
Coefficient of dynamic friction [−] = Dynamic friction force [N] /1.96 [N]

  In the present invention, a support having the above dynamic friction coefficient may be appropriately selected and used, and the dynamic friction coefficient of the support can be controlled by a technique such as adding a trace amount of inorganic particles. As such inorganic particles, for example, particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, silicon oxide, kaolin, and aluminum oxide are preferably added.

  Although the average particle diameter of particle | grains is not specifically limited, 0.1 micrometer-3 micrometers are preferable. Among these, 0.2 μm to 2.5 μm is preferable. By setting it as this range, it becomes easy to adjust a dynamic friction coefficient to the said range, and it becomes easy to suppress suitably the generation | occurrence | production of the wrinkle at the time of tape manufacture. Moreover, by setting it as the said range, the unevenness | corrugation of a support body does not become large too much, it is easy to follow an adhesive layer at the time of lamination, and it becomes easy to contribute also to suppression of the heat shrink in a high temperature environment.

  The content of these particles is not particularly limited, but is preferably 0.01 to 1% by mass. More preferably, it is 0.02-0.5 mass%. If the amount is too small, the dynamic friction force becomes large. If the amount is too large, the dynamic friction force becomes too small.

  The thermal contraction rate of the support is 3% or less. More preferably, it is 2% or less, More preferably, it is 1% or less. By being in the above-mentioned range, when heat is applied to the film during lamination, shrinkage hardly occurs and the productivity is excellent. Moreover, the heat shrinkability as an adhesive tape can also be realized to a high degree. The thermal contraction rate of the support is measured by the following method.

Measured as follows according to JISC2151. A 100 mm × 100 m film is allowed to stand in a dryer at 150 ° C. for 30 minutes, and the size before and after placing in the dryer is measured with a caliper and calculated.
Heat shrinkage rate = 100 × (length before being put in the dryer−length after being put in the dryer) / length before being put in the dryer

  In the present invention, a support having the above heat shrinkage may be appropriately selected and used, and the heat shrinkage of the support can be controlled by a technique such as heat fixation. The heat setting is preferably performed at 160 ° C. to 240 ° C. for 1 second to 600 seconds with respect to the stretched resin film, more preferably 170 ° C. to 235 ° C., and particularly preferably 200 to 230 ° C. It is. By setting it as the said conditions, it becomes easy to adjust the thermal contraction rate of a support body to the said range, and it becomes easy to improve the hydrolysis resistance of a support body.

  Examples of the support having the thickness, the dynamic friction coefficient, and the thermal contraction rate include K100-2.0W and K583-2.5W manufactured by Mitsubishi Plastics.

  As a support to be used, various materials can be used as long as they have the above characteristics, and among them, a synthetic resin film can be suitably used. Specifically, for example, polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), amide resins such as polyamide (nylon) and wholly aromatic polyamide (aramid), polybutyl Polyacrylate resins such as acrylate and polyethyl acrylate, methacrylate resins such as methyl methacrylate (PMMA), polystyrene, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), etc. Polystyrene ketones such as styrene resins, polyether ether ketone (PEEK), and polyether ketone ketone, as well as polyether sulfone (PES), polysulfone, polyvinyl chloride (PVC), Rephenylene sulfide (PPS), polyimide (PI), polyamideimide, polyetherimide (PEI), polyesterimide, polycarbonate (PC), polyacetal, polyarylene ether (polyphenylene ether, etc.), polyphenylene sulfide, polyarylate, polyaryl, polyurethane And epoxy resins. These materials (plastic materials) can be used alone or in combination of two or more.

  Among these, from the viewpoints of thickness accuracy, economy (cost), tensile strength, workability, and the like, a polyester film can be preferably used, and a polyethylene terephthalate film can be particularly preferably used. The polyester film is preferably a biaxially stretched film. High strength can be expressed by biaxial stretching.

  Hereinafter, the manufacturing method of a polyester film is demonstrated concretely. A polyester chip (polyester component) dried or undried by a known method is supplied to a kneading extruder with a coloring pigment or a master batch containing a high concentration of the coloring pigment as necessary, and a temperature equal to or higher than the melting point of the polyester component. Heat to melt. Next, the melted polyester is extruded from a die, and rapidly cooled and solidified on a rotary cooling drum so that the temperature is equal to or lower than the glass transition temperature, thereby obtaining a substantially amorphous unoriented sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed. Also in the melt-extrusion step, shorten the residence time of the polyester in the extruder, and when using a single screw extruder, dry the raw material in advance so that the moisture content is 50 ppm or less, preferably 30 ppm or less. When a shaft extruder is used, a method is adopted in which a vent port is provided and a reduced pressure of 40 hectopascals or less, preferably 30 hectopascals or less, more preferably 20 hectopascals or less is maintained.

  The sheet thus obtained is stretched in the biaxial direction to form a film. Specifically describing the stretching conditions, the unstretched sheet is preferably stretched 2 to 6 times at 70 to 145 ° C. in the longitudinal direction to form a longitudinal uniaxially stretched film, and then 2 to 90 to 160 ° C. in the lateral direction. Perform ~ 6 times stretching and move to heat setting step. Further, at this time, a method of relaxing 0.1 to 20% in the longitudinal direction and / or the transverse direction in the maximum temperature zone of the heat treatment and / or the cooling zone at the heat treatment outlet is preferable. Further, it is possible to add re-longitudinal stretching and re-lateral stretching as necessary.

  The support may have any form of a single layer or a laminate, and is not subject to structural restrictions.

  The surface of the support (particularly, a support made of a plastic material) has a conventional surface treatment, for example, chromic acid treatment, ozone exposure, etc., in order to enhance the adhesion with the pressure-sensitive adhesive layer formed on the support. Oxidation treatment by a chemical or physical method such as flame exposure, high-voltage impact exposure, ionizing radiation treatment, or the like may be performed, or a coating treatment with a primer may be performed.

(Adhesive layer)
The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited. For example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, Appropriately selected from known adhesives such as styrene-diene block copolymer adhesives, vinyl alkyl ether adhesives, polyamide adhesives, fluorine adhesives, improved creep characteristics adhesives, and radiation curable adhesives. Can be used. An adhesive can be used individually or in combination of 2 or more types.

  As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive can be preferably used because it has high adhesion reliability. The acrylic pressure-sensitive adhesive has an acrylic polymer as a pressure-sensitive adhesive component or main ingredient and, as necessary, an appropriate agent such as a crosslinking agent, a tackifier, a softener, a plasticizer, a filler, an anti-aging agent, or a colorant. Additives are included. Acrylic polymer is a polymer that has (meth) acrylic acid alkyl ester as the main component of monomer and can be copolymerized with (meth) alkyl ester as needed (copolymerizable monomer) Body). Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-Methylhexyl acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate , Dodecyl (meth) acrylate, tridecyl (meth) acrylate, (me ) Tetradecyl acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate (meta) ) Acrylic acid C1-20 alkyl ester [preferably (meth) acrylic acid C4-18 alkyl (straight or branched alkyl) ester] and the like. The (meth) acrylic acid alkyl ester can be appropriately selected according to the intended tackiness and the like. The (meth) acrylic acid alkyl ester can be used alone or in combination of two or more.

  Examples of the copolymerizable monomer copolymerizable with the (meth) alkyl ester include carboxyl groups such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. -Containing monomers or anhydrides thereof; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; aromatic vinyl compounds such as styrene and substituted styrene; cyano group-containing monomers such as acrylonitrile; ethylene, propylene, butadiene, etc. Olefins; vinyl esters such as vinyl acetate; vinyl chloride; amide group-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, N, N-dimethyl (meth) acrylamide; hydroxyalkyl (meth) acrylate Contains hydroxyl groups such as glycerin dimethacrylate Monomers; amino group-containing monomers such as aminoethyl (meth) acrylate and (meth) acryloylmorpholine; imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; glycidyl (meth) acrylate and (meth) acrylic Epoxy group-containing monomers such as methyl glycidyl acid; isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate, triethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, ethylene glycol di (meta ) Acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, a polyfunctional copolymerizable monomer (polyfunctional monomer) such as divinylbenzene, and the like. A copolymerizable monomer can be used individually or in combination of 2 or more types. As the copolymerizable monomer, a modifying monomer having a functional group such as a carboxyl group can be suitably used.

  The mass average molecular weight (Mw) of the acrylic polymer is preferably 500,000 to 1,200,000. More preferably, it is 700,000 to 1,200,000. Most preferably, it is 1 million to 1.2 million. By being in the said range, even if it is a thin film, it is easy to express sufficient adhesiveness and heat resistance. The molecular weight is measured in terms of styrene by GPC.

  In the present invention, it is also preferable to add a tackifier resin in order to improve the adhesive strength of the adhesive layer. In addition, by adding these tackifying resins, it is possible to increase the tensile strength and tensile rupture strength, so depending on the acrylic copolymer used, by appropriately adding a tackifying resin, the tensile strength and The tensile breaking strength can be adjusted. Examples of the tackifying resin added to the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive tape of the present invention include rosin resins such as rosin and rosin ester compounds; terpene resins such as diterpene polymers and α-pinene-phenol copolymers. A petroleum resin such as an aliphatic (C5) or aromatic (C9); a styrene resin, a phenol resin, a xylene resin, and the like. In particular, in a pressure-sensitive adhesive composition using an acrylic copolymer having n-butyl (meth) acrylate as a main monomer component, a rosin-based resin and a styrene-based resin are used to achieve a thin and compatible adhesive force and heat resistance. Are preferably used in combination.

  In order to increase the initial adhesive force, it is preferable to mix and use a tackifying resin that is liquid at room temperature. Examples of the tackifying resin that is liquid at normal temperature include liquid resins of the above-described tackifying resin that is solid at normal temperature, and low molecular weight liquid rubbers such as process oil, polyester plasticizer, and polybutene. A terpene phenol resin is particularly preferable. Commercially available products include YP-90L manufactured by Yasuhara Chemical. The addition amount of the liquid crystal tackifying resin is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the acrylic copolymer.

  As addition amount of tackifying resin, it is preferable to add 20-60 mass parts with respect to 100 mass parts of acrylic copolymers. More preferably, it is 30-50 mass parts. Adhesive strength can be improved by adding a tackifying resin.

The gel fraction of the pressure-sensitive adhesive is not particularly limited, but it is preferably 5 to 50% because it is easy to express sufficient adhesiveness and heat resistance even in a thin film, and is preferably 10 to 30%. Is more preferable, and further preferably 15 to 25%. The gel fraction is expressed as a percentage with respect to the original mass by immersing the cured adhesive layer in toluene, measuring the mass after drying of the insoluble matter left after standing for 24 hours, and measuring the mass.
Gel fraction = [(mass after pressure-sensitive adhesive layer is immersed in toluene) / (weight of pressure-sensitive adhesive layer before immersion in toluene)] × 100

  The acrylic polymer can be prepared by a conventional polymerization method such as a solution polymerization method, an emulsion polymerization method, or an ultraviolet irradiation polymerization method.

  Although it does not restrict | limit especially as thickness of each adhesive layer, 0.5 micrometer-4 micrometers are preferable, More preferably, they are 1 micrometer-3 micrometers. It exists in the said range and it is easy to make thinness and adhesive physical property compatible. In particular, when it is less than 0.5 μm, the adhesive strength is remarkably reduced. Moreover, the thickness of the two adhesive layers formed on both surfaces of the support may be the same or different.

(Release liner)
In the double-sided pressure-sensitive adhesive tape of the present invention, a release liner may be provided on the surface of each pressure-sensitive adhesive layer in order to protect the pressure-sensitive adhesive layer. As the release liner, a known release liner may be appropriately selected and used, for example, an ethylene-α-olefin copolymer such as polyethylene, polypropylene, ethylene-propylene copolymer, or a polyolefin composed of a mixture thereof. A release liner made of various resin films such as resin can be preferably used, and these resin films may be foamed. In addition to the resin film, paper such as Japanese paper, western paper, glassine paper, non-woven fabric, metal foil, and the like can also be used. Furthermore, a composite sheet in which these are laminated may be used.

  The surface of these release liners is preferably provided with a release treatment layer in order to impart easy peelability. The release treatment layer can be formed of various release treatment agents used for release liners for double-sided pressure-sensitive adhesive tapes. Examples of such release treatment agents include silicone-based, fluorine-based, and long-chain alkyl-based agents. A release treatment agent or the like can be preferably used. The release treatment layer may be formed on the above resin film by lamination or coating.

  The release force of the release liner may be appropriately adjusted according to the use mode and the like, but the release force for the pressure-sensitive adhesive layer is 0.01 to 2 N / 20 mm, preferably 0.05 to 0.15 N / 20 mm. When peeling the release liner, it is preferable because deformation of the double-sided pressure-sensitive adhesive tape is easily suppressed. The peeling force can be measured by peeling a release liner or a 50 μm thick PET-backed pressure-sensitive adhesive layer in a 180 ° direction at a speed of 0.3 to 10 m / min.

(Production method)
The double-sided pressure-sensitive adhesive tape of the present invention can be produced by a known production method. For example, after the pressure-sensitive adhesive is applied to one surface of the support to form the first pressure-sensitive adhesive layer, or the first pressure-sensitive adhesive layer is formed. In addition, a manufacturing method in which a second pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive to the other surface of the support, or a pressure-sensitive adhesive is applied to the release liner to form a release liner with a pressure-sensitive adhesive layer. The manufacturing method etc. which stick together to both surfaces of a support are mention | raise | lifted.
In particular, in the present invention, a method for producing a double-sided pressure-sensitive adhesive tape comprising the following steps (A1), (B1), (A2), and (B2) is preferred.
Step (A1): A step of applying a pressure-sensitive adhesive to the release treatment surface of the release liner to form a pressure-sensitive adhesive layer on the release liner. Step (B1): formed on the release liner on one surface of the support. A step of forming a first pressure-sensitive adhesive layer on the support by laminating the pressure-sensitive adhesive layer Step (A2): A pressure-sensitive adhesive is applied to the release treatment surface of the other release liner, and the pressure-sensitive adhesive is formed on the release liner. Step (B2): The second pressure-sensitive adhesive layer is formed by laminating the pressure-sensitive adhesive layer formed on the release liner on the other surface of the pressure-sensitive adhesive layer and the support with the release liner. Forming process

  The schematic of the manufacturing method which has the said process is shown to FIGS. In the manufacturing method of FIGS. 2 to 3, an adhesive is applied to the release treatment surface of the release liner 11 by the adhesive coating device 12, and the adhesive is dried and / or cured by the drying and / or ultraviolet irradiation device 13. Thus, a release liner with a pressure-sensitive adhesive layer is obtained (step (A1)). The pressure-sensitive adhesive layer of the obtained release liner with a pressure-sensitive adhesive layer and the support 14 are bonded together through a laminate roll 15 to obtain a single-sided pressure-sensitive adhesive tape 16 in which the support / pressure-sensitive adhesive layer / release liner is laminated (step (step ( B1)). Next, the pressure-sensitive adhesive is applied to the release treatment surface of the other release liner 17 by the pressure-sensitive adhesive coating device 12, and the pressure-sensitive adhesive is dried and / or cured by the drying and / or ultraviolet irradiation device 13, and the pressure-sensitive adhesive layer. After the adhesive release liner is obtained (step (A2)), the adhesive layer of the release liner with the adhesive layer and the support / adhesive layer / release liner obtained through the step (B1) are laminated. The double-sided pressure-sensitive adhesive tape 18 having the pressure-sensitive adhesive layer on both sides of the support is obtained by pasting the support surface of the pressure-sensitive adhesive tape 16 through the laminate roll 15. In the manufacturing method, it is advantageous in the manufacturing process that the release liners 11 and 17, the support 14, the single-sided adhesive tape 16, and the double-sided adhesive tape 18 are each fed out from a roll or wound into a roll. preferable.

  The double-sided pressure-sensitive adhesive tape of the present invention has a tension applied to a support when a pressure-sensitive adhesive layer formed on a release liner is bonded to one side of the support to form a first pressure-sensitive adhesive layer on the support. Even if the thickness of the support is very thin, the double-sided pressure-sensitive adhesive tape can be produced in a good state without causing wrinkles or the like even if the thickness of the support is very thin.

  Therefore, as shown in FIGS. 2 to 3, the double-sided pressure-sensitive adhesive tape of the present invention is preferably produced by a production method comprising the step (A1), the step (B1), the step (A2) and the step (B2). be able to. In particular, by using a production method comprising these, it is possible to produce a double-sided pressure-sensitive adhesive tape or sheet that is stably wound into a roll without causing wrinkles or the like.

  In the step of bonding the adhesive on the release liner and the film, it is preferable to laminate by applying heat (thermal lamination). The temperature is preferably 40 ° C to 80 ° C. By applying heat, even a thin pressure-sensitive adhesive layer can easily follow the unevenness of a film having fine unevenness with good sliding properties. When the temperature is too low, the adhesiveness between the pressure-sensitive adhesive and the film is lowered, and when the temperature is too high, wrinkles are generated. In the pressure-sensitive adhesive tape of the present invention, since the film has a low heat shrinkage rate, wrinkles due to shrinkage hardly occur even when heat is applied, and the productivity is excellent.

  Normally, when a thin support of 3 μm or less is used, the support is not wrinkled when the support and the adhesive tape are bonded unless the tension of the support at the time of manufacture is extremely low (approximately 0). easy. Also, it is difficult to adjust the tension of the support in that way. However, in the present invention, since a support having a specific coefficient of friction is used, a double-sided pressure-sensitive adhesive tape wound in a roll state in a good state can be stably produced without causing special production wrinkles or the like. Can be manufactured. If it is a support body used for this invention, the tension | tensile_strength of 10-300 N / m can be applied. Of these, a tension of 30 to 120 N / m is preferable.

  When the double-sided pressure-sensitive adhesive tape of the present invention is obtained as a double-sided pressure-sensitive adhesive tape wound in a roll shape, the length is not particularly limited as long as it is a long belt-like length, but usually 5 m or more ( Preferably it is 10 m or more, more preferably 20 m or more. When the double-sided pressure-sensitive adhesive tape is wound and long, workability such as when the double-sided pressure-sensitive adhesive tape is cut into parts in advance, sealing, or pressing is improved.

  The double-sided pressure-sensitive adhesive tape of the present invention is a joining member that is required to be thinned, particularly when the clearance between joining parts is extremely small as in the case where the conventional double-sided pressure-sensitive adhesive tape has not been joined (for example, the clearance is 10 μm). The present invention can be suitably applied to joining between parts in the following areas). In particular, for fixing parts such as OA devices such as personal computers, digital cameras and digital video cameras that generate heat during use, and electronic electronic notebooks, mobile phones, PHS, smartphones, game devices, electronic books and other portable electronic terminals, for example It can be suitably used for fixing components such as LCD modules, backlight units, reflection, light shielding, heat dissipation, and magnetic sheets. In particular, since the double-sided pressure-sensitive adhesive tape of the present invention is extremely thin and has good heat resistance, it can be particularly suitably used for fixing a heat-dissipating sheet or a magnetic sheet that is attached to an electronic component that generates heat when used. In addition, the double-sided pressure-sensitive adhesive tape of the present invention is a thin tape excellent in heat resistance that can be applied to such an extremely narrow clearance, but uses a special production method such as reducing the tension applied to the support during production. Even if it does not, it can manufacture suitably, without producing wrinkles etc.

(Usage for fixing heat dissipation sheet)
By installing the heat-dissipating sheet in a local high-temperature part, the heat-dissipating sheet dissipates heat to the entire surface of the electronic device, thereby solving a so-called hot spot. There are two types of graphite sheets used for the heat dissipation sheet: artificial graphite sheets and natural graphite sheets. As the artificial graphite sheet, there is a pyrolytic graphite sheet obtained by pyrolyzing an organic film such as a polyimide film in a high-temperature inert gas atmosphere. In addition, there is a natural graphite sheet in which natural graphite is acid-treated and then heated and expanded into graphite powder. As the graphite sheet used for the heat dissipation sheet, an artificial graphite sheet with less wrinkles is preferably used because heat dissipation is better when there are fewer wrinkles. The thickness of the graphite sheet used for the heat radiating sheet is preferably 10 to 100 μm, and more preferably 15 to 50 μm. By setting the thickness within this range, it can be suitably used for a thin portable electronic terminal device.

  By bonding with the adhesive tape of the present invention, the thermal resistance of the tape can be reduced and the thermal conductivity in the thickness direction can be improved, so that the heat dissipation can be improved. Thinning is also possible.

(Usage for fixing magnetic sheet)
The magnetic sheet is affixed to places where electromagnetic waves are to be blocked, such as the inner surface of the casing of electronic devices and the outer surfaces of various electronic components, thereby preventing external electromagnetic waves from penetrating into the electronic device or inside the electronic device. It is possible to prevent electromagnetic waves from leaking from the outside. Magnetic sheets are Ni-based ferrite magnetic powder, Mg-based ferrite magnetic powder, Mn-based ferrite magnetic powder, Ba-based ferrite magnetic powder, Sr-based ferrite magnetic powder, Fe-Si alloy powder, Fe-Ni alloy powder. , Fe-Co alloy powder, Fe-Si-Al alloy powder, Fe-Si-Cr alloy powder, iron powder, Fe-based amorphous, Co-based amorphous, Fe-based nanocrystal, etc. Easy to demonstrate magnetic performance. An adhesive tape is used for this fixing. By fixing with the adhesive tape of the present invention, even if the magnetic sheet is thickened, it can be thinned as a composite (bonded product of magnetic sheet and adhesive tape).

  Examples of the present invention will be described below in more detail.

(Adhesive Preparation Example 1)
n-butyl acrylate: 97.98 parts, acrylic acid: 2 parts, 4-hydroxybutyl acrylate: 0.02 part, azobisisobutyronitrile: 0.2 part as a polymerization initiator, ethyl acetate In the solution, solution polymerization was performed at 80 ° C. for 8 hours to obtain an acrylic polymer having a weight average molecular weight of 900,000. The acrylic polymer: 100 parts, polymerized rosin ester (trade name “D-135” manufactured by Arakawa Chemical Co., Ltd.): 5 parts, and disproportionated rosin ester (trade name “KE-100” manufactured by Arakawa Chemical Co., Ltd.): 20 Part, petroleum resin (trade name “FTR6100”: 25 parts) was added, and ethyl acetate was added to prepare an adhesive solution having a solid content of 40%. Further, an adhesive A was prepared by adding 0.8 parts of an isocyanate-based crosslinking agent (trade name “NC40” manufactured by DIC), and stirring and mixing so as to be uniform. The gel fraction was 20%.

(Adhesive Preparation Example 2)
n-butyl acrylate: 97.98 parts, acrylic acid: 2 parts, 4-hydroxybutyl acrylate: 0.02 part, azobisisobutyronitrile: 0.3 part as a polymerization initiator, ethyl acetate In the solution, solution polymerization was performed at 90 ° C. for 6 hours to obtain an acrylic polymer having a weight average molecular weight of 500,000. The acrylic polymer: 100 parts, polymerized rosin ester (trade name “D-135” manufactured by Arakawa Chemical Co., Ltd.): 5 parts, and disproportionated rosin ester (trade name “KE-100” manufactured by Arakawa Chemical Co., Ltd.): 20 Part, petroleum resin (trade name “FTR6100”: 25 parts) was added, and ethyl acetate was added to prepare an adhesive solution having a solid content of 40%. Furthermore, 1.5 parts of isocyanate-based crosslinking agent (trade name “NC40” manufactured by DIC) was added, and the mixture was stirred and mixed uniformly to prepare an adhesive B. The gel fraction was 30%.

Example 1
First, the pressure-sensitive adhesive A is applied to a release film (trade name “PET38 × 1K0”) with a roll coater so that the dry thickness is 1.5 μm, and dried at 100 ° C. for 1 minute, and this is a support. A polyester film (trade name “K100-2.0W” manufactured by Mitsubishi Chemical Polyester Co., Ltd .; thickness: 2 μm, dynamic friction coefficient: 0.26, heat shrinkage ratio: 1.4%) is bonded. At this time, the feeding tension of the support was 50 N / m, and the bonding tension of the release film was 300 N / m. Next, the pressure-sensitive adhesive A was applied to a release film (trade name) “PET25 × 1A3” with a roll coater so that the dry thickness was 1.5 μm, and dried at 100 ° C. for 1 minute. A double-sided pressure-sensitive adhesive tape (thickness: 5 μm) was obtained by pasting on the surface that was not provided.

(Example 2)
A double-sided pressure-sensitive adhesive tape (thickness: 10 μm) was obtained in the same manner as in Example 1 except that the dry thickness of the pressure-sensitive adhesive A was changed to 4 μm instead of 1.5 μm.

(Example 3)
A double-sided pressure-sensitive adhesive tape (thickness: 3 μm) was obtained in the same manner as in Example 1 except that the dry thickness of the pressure-sensitive adhesive A was changed to 0.5 μm instead of 1.5 μm.

Example 4
Instead of a polyester film (trade name “K100-2.0W” manufactured by Mitsubishi Chemical Polyester; thickness: 2 μm, dynamic friction coefficient: 0.26, thermal shrinkage: 1.4%) as a support, a polyester film ( The product name “K583-2.5W” manufactured by Mitsubishi Chemical Polyester; thickness: 2.5 μm, dynamic friction coefficient: 0.27, heat shrinkage ratio: 1.5%) was used in the same manner as in Example 1. A double-sided pressure-sensitive adhesive tape (thickness: 5.5 μm) was obtained.

(Example 5)
A double-sided pressure-sensitive adhesive tape (thickness: 5.0 μm) was obtained in the same manner as in Example 1 except that the amount of the isocyanate-based crosslinking agent added was 1.5 parts instead of 0.8 parts. The gel fraction was 30%.

(Example 6)
A double-sided pressure-sensitive adhesive tape (thickness: 5.0 μm) was obtained in the same manner as in Example 1 except that the amount of the isocyanate-based crosslinking agent added was 5.0 parts instead of 0.8 parts. The gel fraction was 50%.

(Example 7)
A double-sided pressure-sensitive adhesive tape (thickness: 5.0 μm) was obtained in the same manner as in Example 1 except that the addition amount of the isocyanate crosslinking agent was changed to 0.5 part instead of 0.8 part. The gel fraction was 5%.

(Example 8)
A double-sided pressure-sensitive adhesive tape (thickness: 5.0 μm) was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive B was used instead of the pressure-sensitive adhesive A. The gel fraction was 30%.

(Comparative Example 1)
Instead of a polyester film (trade name “K100-2.0W” manufactured by Mitsubishi Chemical Polyester; thickness: 2 μm, dynamic friction coefficient: 0.26, thermal shrinkage: 1.4%) as a support, a polyester film ( Product name “C660-2.0W” manufactured by Mitsubishi Chemical Polyester; thickness: 2 μm, dynamic friction coefficient: 0.30, heat shrinkage: 1.6%) An adhesive tape (thickness: 5 μm) was obtained.

(Comparative Example 2)
Instead of a polyester film (trade name “K100-2.0W” manufactured by Mitsubishi Chemical Polyester; thickness: 2 μm, dynamic friction coefficient: 0.26, thermal shrinkage: 1.4%) as a support, a polyester film ( Product name “2DC61” manufactured by Toray Industries, Inc .; thickness: 1.8 μm, dynamic friction coefficient: 0.32, heat shrinkage: 1.5%) : 4.8 μm).

(Comparative Example 3)
Instead of a polyester film (trade name “K100-2.0W” manufactured by Mitsubishi Chemical Polyester; thickness: 2 μm, dynamic friction coefficient: 0.26, thermal shrinkage: 1.4%) as a support, a polyester film ( Product name “K917-1.5W” manufactured by Mitsubishi Chemical Polyester; thickness: 1.5 μm, dynamic friction coefficient: 0.27, heat shrinkage ratio: 30%) An adhesive tape (thickness: 4.5 μm) was obtained.

(Comparative Example 4)
Instead of a polyester film (trade name “K100-2.0W” manufactured by Mitsubishi Chemical Polyester; thickness: 2 μm, dynamic friction coefficient: 0.26, thermal shrinkage: 1.4%) as a support, a polyester film ( Double-sided pressure-sensitive adhesive tape (thickness: 28 μm) in the same manner as in Example 1 except that the product name “S25” manufactured by Unitika Co., Ltd .; thickness: 25 μm, dynamic friction coefficient: 0.28, heat shrinkage rate: 1.0% was used. )

(Dynamic friction coefficient of support)
In accordance with JISK7125, the friction coefficient between the SUS mirror surface and the film surface was measured. As shown in FIG. 4, a film 22 backed with a single-sided adhesive tape “PET50SER made by DIC” 21 was applied and fixed so that a 63 mm × 63 mm slip piece (weight: 1.96 N) 23 and the single-sided adhesive tape 21 were in contact with each other. . Next, the film 22 fixed to the sliding piece was placed so as to contact the SUS mirror surface 25, and the sliding piece 23 was pulled and measured by a load cell 26 at 100 mm / min. The dynamic friction coefficient was calculated by the following equation.
Coefficient of dynamic friction [−] = Dynamic friction force [N] /1.96 [N]

(Shrinkage rate of support)
It measured according to JISC2151. A 100 mm × 100 m film was left in a drier at 150 ° C. for 30 minutes, and the size before and after placing in the drier was measured with a caliper and calculated. The table shows the maximum values of flow (MD) and width (TD).
Heat shrinkage rate = 100 × (length before being put in the dryer−length after being put in the dryer) / length before being put in the dryer

(Gel fraction)
The pressure-sensitive adhesive used in Examples and Comparative Examples is applied to a PET 25 μm film (S25 manufactured by Unitika) so as to have a dry thickness of 30 μm. After curing, it is immersed in toluene and the mass after drying of the insoluble matter remaining after standing for 24 hours is measured and expressed as a percentage of the original mass.
Gel fraction = [(mass after pressure-sensitive adhesive layer is immersed in toluene) / (weight of pressure-sensitive adhesive layer before immersion in toluene)] × 100

(Evaluation)
About the double-sided adhesive tape which concerns on an Example and a comparative example, productivity, the suitability of clearance, adhesive force, high temperature holding power, and heat-resistant shrinkage were measured or evaluated by the following measuring method or evaluation method, respectively. The evaluation results are shown in Table 1.

(productivity)
Judgment was made based on whether or not a double-sided pressure-sensitive adhesive tape could be produced in a roll and in a good form without wrinkles, and evaluation was made as “◯” for those that could be produced and “×” for those that could not be produced. The evaluation results are shown in the column of “productivity availability” in Table 1.

(Evaluation method of clearance suitability)
Apply double-sided adhesive tape to the part where the clearance between parts is 10 μm or less, and judge whether it can be adapted to the clearance. As evaluated. The evaluation results are shown in the “clearance suitability” column of Table 1.

(Measurement method of adhesive strength)
A double-sided adhesive tape was cut to a width of 20 mm, and a test piece backed with 25 μm of PET was prepared. The test piece (20 mm width) was peeled off using a Tensilon tensile tester according to JISZ-0237. : 180 °, tensile speed: 300 mm / min, 23 ° C. × 65% RH, adherend: stainless steel plate). The measurement results are shown in the column of “Adhesive strength (N / 20 mm)” in Table 1.

(High temperature holding power)
A double-sided pressure-sensitive adhesive tape was cut to a width of 20 mm, and a test piece backed with PET 25 μm was produced. A load of 100 g (20 mm × 20 mm) was applied to the test piece (20 mm width) in the vertical direction according to JISZ-0237. The sample was left in an atmosphere of 100 ° C. for 24 hours, and the deviation distance after 24 hours was measured. The measurement results are shown in the column of “Adhesive strength (N / 20 mm)” in Table 1.

(Heat-resistant shrinkage)
The double-sided adhesive tape was cut into 50 mm × 50 mm, bonded to an aluminum plate, left at 100 ° C. for 72 hours, the shrinkage distance was measured, and evaluated according to the following evaluation criteria.
A: Less than 0.1 mm O: 0.1-0.5 mm
×: Over 0.5 mm

  As is clear from Table 1, the double-sided pressure-sensitive adhesive tapes of the present invention of Examples 1 to 8 were excellent in heat shrinkage and productivity even if they were very thin films with a thickness of 10 μm or less. On the other hand, the tapes of Comparative Examples 1 and 2 were inferior in productivity because wrinkles were easily formed on the support during production. The pressure-sensitive adhesive tape of Comparative Example 3 was extremely poor in heat shrinkage. The tape of Comparative Example 4 was thick and could not be used where there was no space.

DESCRIPTION OF SYMBOLS 1 Support body 2,3 Adhesive layer 4,5 Release liner 11,17 Release liner 12 Adhesive coating apparatus 13 Drying and / or ultraviolet irradiation apparatus 14 Support body 15 Laminating roll 16 Single-sided adhesive tape 18 Double-sided adhesive tape 21 Backing Single-sided adhesive tape 22 film (test piece)
23 Sliding piece 24 Pedestal 25 SUS plate 26 Load cell (tensile testing machine)

Claims (8)

A method for producing a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a support made of a polyester film,
Step (A1): Applying an adhesive to the release treatment surface of the release liner to form the adhesive layer on the release liner;
Step (B1): The pressure-sensitive adhesive layer formed on the release liner obtained in the step (A1) is bonded to one surface of the support, and the first pressure-sensitive adhesive layer is formed on the support. Forming a step;
Step (A2): a step of applying an adhesive to the other release treatment surface of the release liner to form an adhesive on the release liner;
Step (B2): The pressure-sensitive adhesive layer of the release liner with the pressure-sensitive adhesive layer obtained through the step (A2) and the support / pressure-sensitive adhesive layer / release liner obtained through the step (B1) were laminated. The both surfaces which have an acrylic adhesive layer on both surfaces of the support body which consists of a polyester film which have the process of bonding together the support body surface of a single-sided adhesive tape through a laminate roll, and forming a 2nd adhesive layer. In the method for producing an adhesive tape,
The total thickness is 2 to 10 μm, the thickness of the support is 1 to 3 μm, the heat shrinkage rate is 3% or less, the dynamic friction coefficient is 0.20 to 0.28, and it is used for fixing the heat dissipation sheet or the magnetic sheet. A method for producing a double-sided pressure-sensitive adhesive tape , comprising: The method for producing a double-sided pressure-sensitive adhesive tape according to claim 1, wherein the support is a support made of a polyethylene terephthalate film. The method for producing a double-sided pressure-sensitive adhesive tape according to claim 2, wherein the acrylic pressure-sensitive adhesive layer is obtained using an acrylic pressure-sensitive adhesive, and the gel fraction of the acrylic pressure-sensitive adhesive layer is 5 to 50%. The method for producing a double-sided pressure-sensitive adhesive tape according to claim 3, wherein the acrylic pressure-sensitive adhesive contains an acrylic polymer having a molecular weight (Mw) of 500,000 to 1,200,000. A double-sided adhesive tape was cut to a width of 20 mm and a test piece backed with an aluminum foil of 50 μm was prepared. A load of 100 g (20 mm × 20 mm) was applied to the test piece (20 mm width) in the vertical direction according to JISZ-0237. The manufacturing method of the double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein a deviation distance when left for 24 hours in an atmosphere of 100 ° C is 2.0 mm or less. The method for producing a double-sided pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 0.5 μm to 4 μm. The method for producing a double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the support is a film containing inorganic particles and polyester. The method for producing a double-sided pressure-sensitive adhesive tape according to any one of claims 1 to 7 , wherein the total thickness is 2 to 5.5 µm.

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