JP6003037B2 - Colored adhesive tape - Google Patents

Description

  The present invention relates to a colored pressure-sensitive adhesive tape, and more particularly to a thin colored pressure-sensitive adhesive tape suitably used for protecting components used in portable electronic devices.

  The adhesive tape has excellent workability and is used as a joining means with high adhesion reliability for fixing and protecting parts in various industrial fields such as office automation 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, the main component parts are required to be thinned, and the pressure-sensitive adhesive tape used for protection thereof is also required to be thinned.

  In addition, these adhesive tapes are required to have very thin colored adhesive tapes of 15 μm or less in order to protect the parts and improve the blinding and appearance of the appearance defects (unevenness, point defects, etc.). Yes.

  As the colored thin adhesive tape, for example, a double-sided adhesive tape comprising a transparent plastic substrate having a thickness of 1 μm or more and less than 10 μm, the total thickness of the tape is less than 30 μm, and the transmittance is 0.3% or less. And the double-sided adhesive tape which has the reflection and light-shielding function in which the reflectance of at least one surface is 55% or more is disclosed (patent document 1). The pressure-sensitive adhesive layer is laminated and integrated on at least one surface of the tape substrate. The tape substrate has a light-shielding layer on one surface of a substrate film having a thickness of 10 μm or less via an intermediate layer containing a rubber compound. A pressure-sensitive adhesive tape for assembling a display device characterized by being laminated and integrated is disclosed (Patent Document 2).

  These adhesive tapes have a very thin total thickness, aiming at clearance compatibility of portable terminal devices that are highly demanded of thinning. However, the thickness of the tapes is still as thick as 20 μm to 54 μm. It was.

  Further, such a colored thin adhesive tape has a markedly poor productivity because the film is easily wrinkled in the process of coloring a thin resin film.

JP 2009-197124 A JP2009-197041

  Under such circumstances, the present invention has been made for the purpose of providing a colored pressure-sensitive adhesive tape having excellent concealability and adhesiveness even in an extremely thin shape and excellent in productivity.

  As a result of intensive studies to achieve the above object, the present inventors have found that the object of the present invention can be achieved by using a resin film having a specific thickness and a specific dynamic friction coefficient, and the present invention has been completed. It came to do.

  That is, the present invention is a colored pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is provided on at least one surface of a colored substrate having a resin film layer and a colored layer, and the resin film layer has a thickness of 2 to 5 μm and a dynamic friction coefficient of 0. Provided is a colored adhesive tape having a total thickness of 15 μm or less.

  The colored pressure-sensitive adhesive tape of the present invention is a colored pressure-sensitive adhesive tape having excellent concealability and adhesiveness and excellent productivity while having an extremely thin configuration with a total thickness of 15 μm or less. Therefore, the colored pressure-sensitive adhesive tape of the present invention can be suitably applied to parts fixing applications for portable electronic devices that have a high demand for downsizing and thinning, and high environmental friendliness, and for protecting thin parts of portable electronic devices. Therefore, it can be suitably applied to a heat-dissipating sheet protecting application and a magnetic sheet protecting application, which are highly demanded to make the tape thinner.

It is a schematic sectional drawing which shows an example of the single-sided colored adhesive tape which has an adhesive layer in the colored layer side of a colored base material. It is a schematic sectional drawing which shows an example of the single-sided colored adhesive tape which has an adhesive layer in the other surface of the colored layer of a colored base material. It is a schematic sectional drawing which shows an example of the double-sided colored adhesive tape which has an adhesive layer on both surfaces of a colored base material. It is the schematic which shows the measuring method of the dynamic friction coefficient of the resin film used for the colored adhesive tape of this invention. It is a schematic process drawing which shows an example of the method of manufacturing the colored base material used for the colored adhesive tape of this invention. It is a schematic process drawing which shows an example of the method of manufacturing the colored adhesive tape of this invention.

  The colored adhesive tape of the present invention is a very thin tape having a total thickness of 15 μm or less, and is a colored adhesive tape in which an adhesive layer is provided on at least one surface of a colored substrate having a resin film layer and a colored layer. In this colored adhesive tape, the resin film layer has a thickness of 2 to 5 μm and a dynamic friction coefficient of 0.1 to 0.4.

[Colored substrate]
The colored substrate used in the present invention has a resin film layer and a colored layer. The colored base material has a total light transmittance of preferably 10% or less, more preferably 3% or less, and most preferably 1% or less, from the viewpoint of securing concealability and light shielding properties. The total light transmittance is a total light transmittance Tt measured according to JIS K7105.

(Resin film layer)
The resin film layer of the colored substrate has a thickness of 2 to 5 μm and a dynamic friction coefficient of 0.1 to 0.4. By setting the thickness and the coefficient of dynamic friction within the range, even when the total thickness of the tape is 15 μm, good productivity, concealability and adhesiveness can be obtained. The dynamic friction coefficient is a value measured in FIG. 4 according to JIS K7125. Specifically, as shown in FIG. 4, the resin film 11 used in the present invention is lined with a single-sided adhesive tape “PET50SER made by DIC” 12, and a slip piece (weight: 0.98 N) 13 of 11 mm × 11 mm is used. And the single-sided adhesive tape 12 were in contact with each other. In addition, the resin film 11 used in the present invention was lined with a single-sided adhesive tape 12 for lining and placed on a pedestal 14. The resin film 11 fixed to the sliding piece was placed in contact with the resin film 11 fixed to the pedestal, and the sliding piece 13 was pulled and measured by the load cell 16 at 100 mm / min. The dynamic friction coefficient was calculated by the following equation.
Coefficient of dynamic friction [-] = Dynamic friction force [N] /0.98 [N]
Here, the single-sided adhesive tape for lining was used to increase the reproducibility of data because the film was thin.

  Since the thickness of the resin film layer can be reduced, it is preferably 2 to 4 μm. More preferably, it is 2-3 micrometers. The coefficient of dynamic friction of the resin film is preferably 0.2 to 0.35, more preferably 0.2 to 0.3, from the viewpoint of productivity. The static friction coefficient is preferably 0.1 to 0.4.

  Various resin films used as the base material of the adhesive tape can be used as the resin film constituting the resin film layer. Among them, a resin film having a tensile strength of 1.5 N / 10 mm to 15 N / 10 mm is preferable because it is difficult to cut even in an extremely thin configuration. Further, the type of resin to be used is not particularly limited, but a polyester film having good dimensional stability and strength can be preferably used. A preferred tensile strength is 2.5 N / 10 mm to 15 N / 10 mm. The tensile strength is measured by pulling at a pulling speed of 300 mm / min according to JIS Z0237-2000.

  Various polyester films can be used as the polyester film. Specifically, for example, a film obtained by singly or copolymerizing polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polybutylene terephthalate (PBT) can be used. The polyester film is preferably a biaxially stretched film from the viewpoint of dimensional stability and strength. Among these, a biaxially stretched PET film is preferable.

  Various color pigments may be mixed in the polyester film, but a transparent film containing no colorant is preferable in order to achieve high strength with a thin film of 2 to 5 μm.

(Lubricant)
In order to realize the above dynamic friction coefficient, it is preferable to blend a lubricant in the resin film. As the lubricant, a particulate material or a non-particulate material is used. As particles, fine particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, silicon sulfate, and aluminum oxide are used. As non-particulate ones, fatty acid amides and alkylene bis fatty acid amides are used. Among them, it is preferable to use a particle size lubricant having an average particle size of 3.0 μm to 7.0 μm because it has little influence on the ink and the pressure-sensitive adhesive and can exhibit slipperiness. More preferably, silica having an average particle size of 3.0 μm to 7.0 μm is preferable. Among these, colloidal silica is particularly preferable. The content of the lubricant is preferably 0.01 to 10% by mass, more preferably 0.02 to 1% by mass in the resin film. The average particle diameter may be measured by any of various measurement methods, but the above numerical values are average particles obtained from an average value obtained by measuring the maximum particle diameter of 50 to 200 particles, preferably 100 particles, from a micrograph. Is the diameter.

  Hereinafter, taking a polyester film as an example, a method for producing a resin film will be specifically described. Supply dried or undried polyester chips (polyester component) by a known method to a kneading extruder with a lubricant, a coloring pigment, or a master batch containing a high concentration of coloring pigment, if necessary. Heat to a certain temperature and 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.

  In addition, the resin film layer may have any form of a single layer or a laminate, and is not subject to structural restrictions.

  The surface of the resin film layer (especially a support made of a plastic material) has a conventional surface treatment, for example, chromic acid, in order to enhance adhesion with a colored layer or an adhesive layer formed on the resin film layer. Oxidation treatment by chemical or physical methods such as treatment, exposure to ozone, exposure to flame, exposure to high piezoelectric impact, ionizing radiation treatment, or the like may be performed, and coating treatment with a primer may be performed.

(Colored layer)
Although the colored layer in the colored adhesive tape of this invention is not specifically limited, It is preferable that it is a layer which consists of colored inks. The ink layer is preferably a layer made of a polyester urethane-based ink whose main binder component is a polyester urethane-based resin having a glass transition temperature (Tg) of −30 to 10 ° C. Polyester urethane inks are less likely to curl even with thin films than polyester and acrylic inks, and can disperse pigments at high concentrations.

  The surface roughness Ra of the colored layer is preferably 0.05 μm to 0.4 μm. More preferably, it is 0.1 micrometer-0.3 micrometer, Most preferably, it is 0.2 micrometer-0.3 micrometer. When Ra is 0.05 μm or more, the productivity in the coloring step is improved, and when it is 0.4 μm or less, the followability of the adhesive to the colored layer surface is easily improved. Ra is measured according to JIS B0601.

  In order to achieve Ra in the above range, it is preferable to add a particle-based antiblocking agent such as silica, calcium carbonate, calcium phosphate, talc, urethane beads, acrylic beads, silicone beads. The average particle size of the particle size blocking inhibitor is preferably 1.0 μm to 3.0 μm by the Coulter method. Among these, silica having an average particle size of 1.0 μm to 3.0 μm is preferable, and silica having an average particle size of 1.5 μm to 2.0 μm is more preferable.

(Ink composition)
As the composition of the colored ink, polyester, acrylic, urethane and the like can be used, and among them, polyester urethane is preferable. The polyester urethane resin preferably has a glass transition temperature of -30 to 10 ° C. By using the polyester urethane-based resin, there is little curl even if it is applied to a thin film, even if it is an ultra-thin adhesive tape configuration, and it is strong even for thin resin films that are difficult to easily adhere to such as corona treatment. Adhesion and good adhesion and reworkability can be realized. More preferably, it is -25 degreeC-0 degreeC, Most preferably, it is -20 degreeC--5 degreeC. The glass transition temperature of the polyester urethane resin is a peak temperature of tan δ of the dynamic viscoelastic spectrum at a frequency of 1 Hz measured as follows.

(Measurement of dynamic viscoelasticity of polyester urethane resin)
Polyester urethane resin is formed to a thickness of 50 μm with a bar coater. Next, from a specimen cut to a sample length of 20 mm (sample length of 20 mm, film thickness of 50 μm) using a viscoelasticity tester from −150 ° C. to 250 ° C. at a frequency of 1 Hz and a temperature increase time of 3 ° C./1 minute. The storage elastic modulus (G ′) and the loss elastic modulus (G ″) are measured. The loss tangent tan δ is calculated by the following calculation formula.
Loss tangent tan δ = G ″ / G ′
Examples of the viscoelasticity tester include DMS210, DMS220, and DMS6100 manufactured by Seiko Instruments Inc.

  The polyester urethane resin is obtained by a polycondensation reaction of a diisocyanate compound, a polyester polyol compound, a low molecular weight chain extender, and the like, and is a resin having high flexibility and elasticity having many urethane bonds in the molecule. The polyester polyol compound contains a dicarboxylic acid as a monomer component, and the aromatic dicarboxylic acid in the dicarboxylic acid is preferably 30 to 90% by mass because the tan δ peak temperature of the polyester urethane resin can be easily controlled within the above range. The molecular weight of the polyester polyol is not particularly limited, but is preferably 800 to 6,000 in terms of number average molecular weight. When the number average molecular weight of the polyester polyol is 800 or more, the printability and coating suitability of the resulting polyester urethane resin are likely to be suitable, and when it is 6,000 or less, the drying property and the blocking resistance are easily improved. . The polyester urethane resin preferably has a mass average molecular weight of 1,000 to 500,000, more preferably 20,000 to 150,000.

  The average mass molecular weight is a standard polystyrene conversion by gel permeation chromatography (GPC). As measurement conditions, TSKgel GMHXL [manufactured by Tosoh] is used as the column, the column temperature is 40 ° C., the eluent is tetrahydrofuran, the flow rate is 1.0 mL / min, and the standard polystyrene is TSK standard polystyrene.

  Specific examples of the diisocyanate compound suitably used for the polyester urethane resin include, for example, methylene diisocyanate, isopropylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and dimer. Chain aliphatic diisocyanates such as dimerisocyanate in which the carboxyl group of the acid is substituted with an isocyanate group; cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-di (isocyanate methyl) Cycloaliphatic diisocyanates such as cyclohexane and methylcyclohexane diisocyanate; 4,4′-diphenyldimethylmethane diiso Dialkyldiphenylmethane diisocyanate such as anate, tetraalkyldiphenylmethane diisocyanate such as 4,4′-diphenyltetramethylmethane diisocyanate, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, Aromatic diisocyanates such as 4,4′-dibenzyl isocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, m-tetramethylxylylene diisocyanate; amino acid diisocyanates such as lysine diisocyanate Etc. These polyisocyanate compounds including these diisocyanate compounds are used alone or in admixture of two or more. Of these, isophorone diisocyanate is preferable because it has an appropriate elasticity.

  Polyester polyol compounds include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentane. Saturated or unsaturated low molecular weight such as diol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4-butynediol, dipropylene glycol, bisphenol A, hydrogenated bisphenol A Diols such as glycols and adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid Or their corresponding acids Compounds obtained dehydration condensation etc. anhydride and the like. Among these, those obtained by dehydration condensation of aromatic dicarboxylic acid and diol are preferable, and those obtained by dehydration condensation of adipic acid and neopentyl glycol are preferable because they have appropriate elasticity.

  Examples of the chain extender include various known diamines and glycols. Examples of diamines include ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4′-diamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di- Diamines having a hydroxyl group in the molecule such as 2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and the carboxyl group of dimer acid are converted to amino groups. A typical example is dimer diamine.

  Furthermore, a reaction terminator can be used in the urethanization reaction. Examples of such a reaction terminator include dialkylamines such as di-n-butylamine, aromatic amines such as benzylamine and dibenzylamine, alkanolamines such as diethanolamine, and alcohols such as techanol and isopropanol alcohol. Is mentioned.

  The polyester urethane resin is preferably a polyester urethane urea resin provided with a urea bond.

  There is no restriction | limiting in particular about the method of manufacturing a polyester urethane urea resin, What is necessary is just to manufacture according to the method similar to the manufacturing method of a general polyester urethane urea resin. For example, a diisocyanate component and a polyol component are reacted at an equivalent ratio of excess isocyanate groups to form a prepolymer of both terminal isocyanate groups, which are then reacted with a chain extender and optionally a reaction terminator in a suitable solvent. However, the compounds can also be reacted together.

  Examples of the solvent used in the production method include solvents that are generally known as solvents for printing inks. For example, aromatic solvents such as toluene and xylene, alcohol solvents such as methanol, ethanol, isopropanol and n-butanol, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and ester solvents such as ethyl acetate and butyl acetate These can be used alone or in a mixture of two or more. In particular, it is preferable to use toluene as an aromatic solvent.

  The ink used for the colored layer has the above-mentioned polyester urethane resin as a main binder component, and other resins may be used in combination as long as the effects of the present invention are not impaired. However, the polyester urethane resin is 90% by mass in the binder component. It is preferable to contain the above, more preferably 95% by mass or more, and particularly preferably one containing substantially no other resin.

  In the ink, various isocyanate curing agents can be used as a curing agent. Among them, an aliphatic or alicyclic isocyanate curing agent has little curling due to curing shrinkage and is suitable for use in a thin film.

  Aliphatic or alicyclic isocyanates include hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, trimethylhexamethylene isocyanate, 1,6,11-undecane triisocyanate, lysine diisocyanate, lysine ester triisocyanate, 1,8-diisocyanate-4 -Isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate are used. Further, trimers of these isocyanates can be preferably used, and among them, diisocyanate adducts, biurets, and nurates are preferable. Among these, hexamethylene diisocyanate or isophorone diisocyanate adduct, biuret, or nurate is preferable because the elastic modulus is easily controlled, and biuret or nurate is particularly preferable. A hardening | curing agent may be added independently and may add 2 or more types.

  In addition, it is preferable to add a cellulose-based resin having high dispersibility as a dispersant because high concealability is obtained. Examples of the cellulose resin include nitrified cotton and cellulose acetate propionate. The addition amount of the resin is preferably 0.05 to 10% by mass with respect to the solid content of the ink. More preferably, it is 0.1-3 mass%.

  The ink used for the colored layer contains a binder resin and a coloring material. As the coloring material, known and commonly used pigments and dyes not containing halogen can be used, carbon black in the case of black, titanium oxide, calcium carbonate, barium sulfate in the case of white, yellow iron oxide in the case of yellow, Red is preferred for brown, blue for cyanine blue, silver for aluminum powder, and pearl for mica titanium powder from the viewpoint of weather resistance, heat resistance, and dispersibility in ink resins. Of these, carbon black is preferable because of its excellent concealability.

  What is necessary is just to adjust suitably according to a use etc. as addition amount of a coloring material, and 10 to 70% in the ink solid content containing a coloring material is preferable. More preferably, it is 40 to 50%. If it is 10% or more, concealment properties are suitably exhibited, and if it is 70% or less, dispersion is good.

  The ink constituting the colored layer preferably contains an anti-blocking agent. Generation | occurrence | production of the pinhole by blocking can be suppressed by containing an antiblocking agent. Anti-blocking agents include particulate anti-blocking agents such as silica, calcium carbonate, calcium phosphate, talc, urethane beads, acrylic beads, and silicone beads, and organics such as polyethylene wax (PE wax), fatty acid amides, fatty acid esters, and higher fatty acids. It is preferable to use a compound-based antiblocking agent. The particle-based anti-blocking agent prevents the blocking by forming irregularities on the surface of the ink layer and reducing the contact area between the ink surface and the back surface. On the other hand, the organic compound-based antiblocking agent prevents blocking by bleeding out on the surface of the ink layer. Therefore, it is preferable to use a particle-based anti-blocking agent and an organic compound-based anti-blocking agent in combination. In particular, silica having excellent slipperiness is preferable as the particle-based antiblocking agent. The average particle size of the particle size blocking inhibitor is preferably 1.0 μm to 3.0 μm by the Coulter method, because it is easy to achieve both high slipperiness and concealment. Among these, 1.5 micrometers-2.0 micrometers are preferable.

  The addition amount of the particle size blocking inhibitor is preferably 0.5 to 10% by mass with respect to the ink solid content. Among these, 1-5 mass% is more preferable. If it is 0.5% by mass or more, the effect of preventing blocking is suitably exhibited, and if it is 10% by mass or less, the cohesiveness of the ink film can be sufficiently ensured, and scratches are hardly scratched. On the other hand, the addition amount of the organic blocking inhibitor is preferably 0.5 to 10% by mass with respect to the ink solid content. Among these, 2-7 mass% is more preferable. If it is 0.5 mass% or more, the effect of blocking prevention is acquired suitably, and the adhesiveness and rework property with an adhesive will become favorable in it being 10 mass% or less. Moreover, you may contain other various additives as needed.

  The ink layer has a thickness of 0.5 to 5 μm. More preferably, it is 1-4 micrometers. More preferably, it is 1-3 micrometers. By being in the said range, concealability and thinness can be highly compatible.

(Halogen content)
The colored layer in the colored adhesive tape of the present invention preferably has a halogen content in the colored layer of 0.3% by mass or less. The content is preferably 0.05% by mass or less, and particularly preferably contains substantially no halogen. Here, the halogen content is a detection amount when analyzed by fluorescent X-rays. For example, as a fluorescent X-ray analyzer, “ZSX Primus”, “ZSX Primus II”, etc. manufactured by Rigaku are listed.

[Adhesive layer]
Although the thickness of the adhesive layer of the colored adhesive tape of this invention is not specifically limited, It is preferable that they are 0.5 micrometer-5 micrometers. More preferably, it is 1 micrometer-3 micrometers. By being in the above range, good adhesive properties can be realized even when an extremely thin configuration is adopted. In particular, when the thickness is less than 0.5 μm, the adhesive force tends to be remarkably reduced.

  The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the colored pressure-sensitive adhesive tape of the present invention is not particularly limited. For example, an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyester 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. What contains 30% or more of butyl acrylate is preferable because of excellent adhesion and heat resistance.

  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. What contains 0.5-4.0% of acrylic acid is preferable since it is excellent in adhesiveness and heat resistance.

  The mass average molecular weight (Mw) of the acrylic polymer is preferably 500,000 to 1,200,000. More preferably, it is 500,000 to 1,000,000. 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. It is preferable to use a mixture of

  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 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 10-70 mass parts with respect to 100 mass parts of acrylic copolymers. More preferably, it is 20-60 mass parts. Adhesive strength can be improved by adding a tackifying resin.

The gel fraction of the pressure-sensitive adhesive layer is not particularly limited, but it is preferably 5 to 50% because it is easy to express sufficient adhesion and heat resistance even in a thin film, and is preferably 10 to 40%. More preferably, it is 13 to 35%. 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 storage elastic modulus of the pressure-sensitive adhesive layer is preferably 10 ⁴ to 4 × 10 ⁵ Pa at 25 ° C. at a frequency of 1 Hz. More preferably, it is 5 * 10 < ⁴ > -2 * 10 < ⁵ > Pa. By being in the said range, even if it is a thin adhesive layer, wettability (initial tack) and adhesive force are highly compatible easily.

  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.

[Colored adhesive tape]
The colored adhesive tape of the present invention is a colored adhesive tape in which an adhesive layer is provided on at least one surface of a colored substrate having a resin film layer and a colored layer. For example, FIG. 1 (single-sided tape: colored colored substrate) Configuration having a pressure-sensitive adhesive layer on the layer side), configuration of a single-sided pressure-sensitive adhesive tape as shown in FIG. 2 (single-sided tape: a configuration having a pressure-sensitive adhesive layer on the other surface side of the colored substrate), or FIG. A double-sided pressure-sensitive adhesive tape such as (double-sided tape) may be used. The colored pressure-sensitive adhesive tape has a total thickness of 15 μm or less. Thus, the colored pressure-sensitive adhesive tape of the present invention is extremely thin and can be suitably used for protecting and joining parts used in electronic devices with little space, particularly portable electronic devices. Moreover, since the base material is colored, it is excellent in visibility and concealment. In addition, as long as it is within the thickness range of the colored adhesive tape of the present invention, each layer may have a configuration in which a plurality of layers are laminated, or may have a configuration in which other functional layers are included between each layer. .

The colored pressure-sensitive adhesive tape of the present invention may be a single-sided tape or a double-sided pressure-sensitive adhesive tape as described above, but in a single-sided pressure-sensitive adhesive tape, more suitable depending on the laminated surface of the pressure-sensitive adhesive layer. It is possible to achieve effects and impart functions. For example, in the structure having the pressure-sensitive adhesive layer on the colored layer side of the colored substrate, the colored layer used in the present invention has good adhesion to the pressure-sensitive adhesive layer, so that the colored layer / pressure-sensitive adhesive layer interface at the time of reworking Can be suitably suppressed, and excellent reworkability can be realized even when a strongly adhesive pressure-sensitive adhesive layer is used.
In addition, in the structure having the adhesive layer on the surface side other than the colored layer of the colored substrate, the colored layer with a matte feeling becomes the tape surface, so a transparent protective film is provided on the tape surface during transportation, etc. It is easy to prevent forgetting to remove the glossy protective film. That is, when the glossy protective film is peeled off, a colored layer with a matte appearance appears, so that forgetting to peel off can be prevented. In this application, the effect can be easily achieved by improving the matte feeling of the colored layer.

(Release liner)
In the 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. A known release liner may be appropriately selected and used as the release liner. A resin film that has been subjected to a release treatment is preferred because of its excellent smoothness. Of these, a polyester film having excellent heat resistance is preferably subjected to a release treatment. In addition, the total thickness of the colored adhesive tape as used in the field of this invention means the thickness of the adhesive tape itself which does not contain the said release liner.

  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 process)
The production process of the colored adhesive tape of the present invention includes a process of providing a colored layer on a resin film and a process of providing an adhesive layer on a colored resin film. Direct gravure printing, reverse gravure printing, and small-diameter gravure printing are used as the step of providing the colored layer on the resin film. As shown in FIG. 5, when the film is separated from the sleeve roll or when the colored film is wound, when a thin resin film is used, wrinkles are generated and the productivity is remarkably deteriorated. Since the colored adhesive tape of the present invention uses a resin film having a specific thickness and dynamic friction coefficient, wrinkles are less likely to occur and the productivity is excellent.

  The step of providing the pressure-sensitive adhesive layer on the colored resin film is preferably a step of providing the pressure-sensitive adhesive layer on the release liner and laminating it on the colored resin film (FIG. 6). Since the colored pressure-sensitive adhesive tape of the present invention has good slipperiness of the resin film, it is less prone to wrinkling during lamination and has excellent productivity.

  The pressure-sensitive adhesive tape of the present invention can be suitably applied to the protection or joining of members that are required to have a thin layer and concealability / visibility. 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 adhesive tape of the present invention is extremely thin and has good heat resistance, it can be particularly suitably used for protecting and fixing a heat-dissipating sheet or a magnetic sheet to be attached to an electronic component that generates heat by use. .

(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. Since these graphite sheets are very brittle, an adhesive tape is used to protect them.

  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. Furthermore, since the pressure-sensitive adhesive tape of the present invention is excellent in concealability, it is possible to make it difficult to see unevenness in the appearance of the heat dissipation sheet, and to improve the productivity of the heat dissipation sheet.

(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. Since these magnetic sheets are very brittle, an adhesive tape is used to protect them, but even if the magnetic sheet is thickened by protecting with the adhesive tape of the present invention, 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, styrene-based resin (trade name “FTR6100”: 25 parts), terpene phenol resin (trade name “YP90LL”: manufactured by Mitsui Chemicals): 1 part, ethyl acetate is added, and the pressure-sensitive adhesive has a solid content of 40%. The solution was adjusted. 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% and the storage elastic modulus at 25 ° C. was 9 × 10 ⁴ Pa.

[Production example of polyester urethane resin]
(Polyester urethane resin A)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube is provided with 223.1 parts of polyester diol of Mn = 1,000 obtained from adipic acid and neopentyl glycol and 64.4 parts of isophorone diisocyanate. Was reacted at 90 ° C. for 15 hours under a nitrogen stream. Next, 11.3 parts of isophorone diamine, 1.2 parts of di-n-butylamine, 175 parts of toluene, 315 parts of ethyl acetate, and 210 parts of isopropylene alcohol were added and reacted at 40 ° C. for 3 hours under a stirring frame. A polyester urethane resin A having a partial concentration of 30.0%, a Gardner viscosity ST (25 ° C), an amine value of 0.5, and Mw of 100,000 was obtained. The obtained resin had a glass transition temperature of −20 ° C.

(Measurement of dynamic viscoelasticity of polyester urethane resin)
Polyester urethane resin is formed to a thickness of 50 μm with a bar coater. Next, a test piece (sample length 20 mm, film thickness 50 μm) cut to a sample length of 20 mm was used with a viscoelasticity tester (trade name: DMS210, manufactured by Seiko Instruments Inc.), with a frequency of 1 Hz and a heating time of 3 ° C. / The storage elastic modulus (G ′) and loss elastic modulus (G ″) from −150 ° C. to 250 ° C. were measured under the condition of 1 minute. The loss tangent tan δ was calculated from the following calculation formula. The glass transition temperature was taken.
Loss tangent tan δ = G ″ / G ′

[Black ink production example 1]
4 parts of “Carbon Degussa Special 4A” manufactured by Degussa, 6 parts of “Carbon Special 250P” manufactured by Degussa, 40 parts of polyester urethane resin A (glass transition temperature = −20 ° C.), silica “Silicia 350D” manufactured by Fuji Silysia Chemical (Average particle size = 1.8 μm (Coulter method)) 1 part, 23 parts methyl ethyl ketone, 13 parts toluene, 6 parts ethyl acetate, 3 parts N-propyl acetate, 3 parts isopropyl alcohol, sand mill 4 parts of a curing agent “KR90” (biuret form of hexamethylene didiisocyanate) manufactured by DIC and 35 parts of a diluent “Die Reducer V No. 20” manufactured by DIC Black ink A was prepared. In addition, resin represents solid content ratio.

[Black ink production example 2]
The silica “Silicia 350D” (average particle size = 1.8 μm) manufactured by Fuji Silysia Chemical in Production Example 1 of black ink was replaced with the silica “Silicia 310” manufactured by Fuji Silysia Chemical (average particle size = 1.5 μm (Coulter method)). A black ink B was prepared in the same manner except for the above.

[Black ink production example 3]
The silica “Silicia 350D” (average particle size = 1.8 μm) manufactured by Fuji Silysia Chemical in Production Example 1 of black ink was replaced with silica “Silicia 430” (average particle size = 2.5 μm (Coulter method)) manufactured by Fuji Silysia Chemical. A black ink C was prepared in the same manner except that.

[Creation of base material]
(Black ink coat film A)
A polyester film K100-2.0W (thickness: 2.0 μm, dynamic friction coefficient: 0.36) made of Mitsubishi resin is gravure-coated with the gravure coater of FIG. A roll having a length of 1000 m was wound and aged at 40 ° C. for 1 day to obtain a black ink coat film A. The surface roughness Ra of the ink surface was 0.15 μm.

(Black ink coat film B)
Similar to the black ink coat film A except that the polyester film K330-2.0W (thickness: 4.5 μm, dynamic friction coefficient: 0.22) made of Mitsubishi resin is used instead of the polyester film K100-2.0W made of Mitsubishi resin. A black ink coat film B was obtained. The surface roughness Ra of the ink surface was 0.15 μm.

(Black ink coat film C)
Black ink coat film C as well as black ink coat film A except that Toray polyester film 5AF53 (thickness: 4.5 μm, dynamic friction coefficient: 0.33) was used instead of Mitsubishi resin polyester film K100-2.0W Got. The surface roughness Ra of the ink surface was 0.15 μm.

(Black ink coat film D)
Black ink coat film D, similar to black ink coat film A, except that Toray polyester film 4AF53 (thickness: 4.5 μm, dynamic friction coefficient: 0.35) was used in place of Mitsubishi resin polyester film K100-2.0W Got. The surface roughness Ra of the ink surface was 0.15 μm.

(Black ink coat film E)
A black ink coat film E was obtained in the same manner as the black ink coat film B except that the black ink B was used instead of the black ink A. The surface roughness Ra of the ink surface was 0.1 μm.

(Black ink coat film F)
A black ink coat film F was obtained in the same manner as the black ink coat film B except that the black ink C was used instead of the black ink A. The surface roughness Ra of the ink surface was 0.3 μm.

(Black ink coat film G)
Black ink coat film G in the same manner as black ink coat film A, except that Toray polyester film Y808 (thickness: 4.5 μm, dynamic friction coefficient: 0.42) was used instead of Mitsubishi resin polyester film K100-2.0W. Got. The surface roughness Ra of the ink surface was 0.15 μm.

(Black ink coat film H)
Black ink coat film H in the same manner as black ink coat film A, except that Toray polyester film 2DC61 (thickness: 1.8 μm, dynamic friction coefficient: 0.41) was used instead of Mitsubishi resin polyester film K100-2.0W Got. The surface roughness Ra of the ink surface was 0.15 μm.

(Black ink coat film I)
A black ink coat film I was obtained in the same manner as the black ink coat film A, except that Toray polyester film S25 (thickness: 25 μm, dynamic friction coefficient: 0.37) was used instead of Mitsubishi resin polyester film K100-2.0W. It was. The surface roughness Ra of the ink surface was 0.15 μm.

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 4.0 μm, and dried at 100 ° C. for 1 minute. The black ink coat film A was bonded to the ink surface and further aged at 40 ° C. for 2 days.

(Example 2)
An adhesive tape of Example 2 was obtained in the same manner as in Example 1 except that the black ink coat film B was used instead of the black ink coat film A.

(Example 3)
An adhesive tape of Example 3 was obtained in the same manner as in Example 1 except that the black ink coat film C was used instead of the black ink coat film A.

Example 4
An adhesive tape of Example 4 was obtained in the same manner as in Example 1 except that the black ink coat film D was used instead of the black ink coat film A.

(Example 5)
An adhesive tape of Example 5 was obtained in the same manner as in Example 1 except that the black ink coat film E was used instead of the black ink coat film A.

(Example 6)
An adhesive tape of Example 6 was obtained in the same manner as in Example 1 except that the black ink coat film F was used instead of the black ink coat film A.

(Comparative Example 1)
A pressure-sensitive adhesive tape of Comparative Example 1 was obtained in the same manner as in Example 1 except that the black ink coat film G was used instead of the black ink coat film A.

(Comparative Example 2)
A pressure-sensitive adhesive tape of Comparative Example 2 was obtained in the same manner as in Example 1 except that the black ink-coated film H was used instead of the black ink-coated film A.

(Comparative Example 3)
A pressure-sensitive adhesive tape of Comparative Example 3 was obtained in the same manner as in Example 1 except that the black ink coat film I was used instead of the black ink coat film A.

(Evaluation)
The following evaluation was performed about the adhesive tape which concerns on an Example and a comparative example. The evaluation results are shown in Tables 1 and 2.

(Thickness)
The thickness was measured with a Nikon thickness meter “DIGIMICRO MFC-101”.

(Dynamic friction coefficient of resin film)
The friction coefficient between the film surface and the film surface was measured according to JISK7125. As shown in FIG. 6, a film 22 backed with a single-sided adhesive tape “PET50SER made by DIC” 21 was applied, and the 11 mm × 11 mm slip piece (weight: 0.98N) 23 and the single-sided adhesive tape 21 were fixed in contact with each other. . Next, the film 22 fixed to the slip piece was placed in contact with the film surface 25, and the slide 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] /0.98 [N]

(Average particle size of lubricant in resin film)
The surface of the resin film is magnified 1000 times in a transmission mode with a microscope (digital microscope KH-7700 manufactured by HIROX), photographed, and the particle size of the largest particle is measured. A photograph of 100 sheets (100 particles) is observed, and the average value obtained by measuring the maximum particle diameter of the particles is obtained.

(Ink layer surface roughness)
Using the surface shape analyzer (Tokyo Seimitsu Co., Ltd., Surfcom 575A), the black ink coat film obtained above according to JIS-B0651 (2001), stylus tip radius 5 μm, stylus tip taper angle 90 °, The arithmetic average roughness (Ra) when the surface contour curve was measured under conditions of a measuring force of 4 mN, a cutoff value of 0.8 mm, a measuring speed of 0.3 mm / s, and a reference length of 5 mm was measured.

(Adhesive strength)
The adhesive tape is cut to a width of 25 mm and peel adhesive strength (peeling angle: 180 °, tensile speed: 300 mm / min, 23 ° C. × 50% RH, adherend) using a Tensilon tensile tester according to JIS Z0237. : Stainless steel plate, sticking time: 1 hour). The measurement results are shown in the column of “Adhesive strength (N / 25 mm)” in Table 1.

(Holding power)
The adhesive tape was cut into a width of 25 mm, a load of 100 g (25 mm × 25 mm) was applied in the vertical direction according to JIS Z0237, and the drop time was measured in an atmosphere of 100 ° C. The measurement results are shown in the “holding power” column of Table 1.

(Transmittance)
The total light transmittance of the adhesive tape was measured with “HR-100” manufactured by Murakami Color Research Laboratory according to JIS K7105.

(Concealment)
A black Mackie (thin) line is drawn on the aluminum plate, and a tape is pasted after 1 day. Further, it is evaluated whether or not a line can be seen from the tape surface after being left at 23 ° C. for 1 day.
A: The line is not visible at all. O: The line is slightly visible. X: The line is clearly visible.

(Halogen content)
The halogen content was measured by FP method using wavelength dispersion type fluorescent X-ray “ZSX Primus” manufactured by Rigaku.
○: Less than 0.01% ×: 0.01% or more

(productivity)
When a black ink coat film was produced at 60 m / min using the gravure coater of FIG. 5, it was evaluated by the condition of wrinkles.
(Double-circle): Wrinkles do not enter at all. (0 locations / 1000m)
○: Almost no wrinkles. (1-10 locations / 1000m)
X: Wrinkles enter and cannot be wound. (11 locations / 1000m)

  As is clear from Table 1, the pressure-sensitive adhesive tapes of the present invention of Examples 1 to 6 were excellent in concealability, adhesiveness, and productivity even when the thickness was 15 μm or less, which was a very thin film. On the other hand, the tapes of Comparative Examples 1 and 2 were inferior in productivity. Moreover, since the tape of Comparative Example 3 was thick, it was not suitable for the demand for thinness.

DESCRIPTION OF SYMBOLS 1 Colored base material 2 Colored layer 3 Resin film layer 4 Adhesive layer 11 Resin film 12 Single-sided adhesive tape for backing 13 Sliding piece 14 Base 15 Load cell (tensile tester)
DESCRIPTION OF SYMBOLS 21 Resin film 22 Colored base material 23 Colored ink 24 Sleeve roll 25 Drying device and / or ultraviolet irradiation device 31 Release liner 32 Adhesive coating device 33 Drying and / or ultraviolet irradiation device 34 Colored substrate 35 Laminating roll 36 Single-sided adhesive tape

Claims (6)

And the graphite sheet, a radiating sheet, characterized in that it comprises a colored adhesive tape and is bonded together configuration, the pressure-sensitive adhesive layer on one surface of the colored substrate the colored adhesive tape and a resin film layer and the colored layer A single-sided colored adhesive tape provided, wherein the resin film layer has a thickness of 2 to 5 μm, a dynamic friction coefficient of 0.1 to 0.3 , the colored layer is an ink layer, and the thickness of the ink layer is A heat dissipating sheet having a thickness of 0.5 μm to 3 μm and a total tape thickness of 15 μm or less. The heat dissipation sheet according to claim 1, wherein the resin film layer is a polyester film layer. The heat radiation sheet according to claim 1 or 2, wherein the colored substrate has a total light transmittance of 10% or less. The heat dissipation sheet according to any one of claims 1 to 3, wherein the resin film layer contains a lubricant having an average particle diameter of 3 µm to 7 µm. The heat-radiating sheet according to claim 1, wherein the colored layer is made of colored ink, and the surface roughness Ra of the colored layer surface is 0.05 to 0.4 μm. The heat-radiation sheet according to any one of claims 1 to 5, wherein the colored ink contains a particle-based antiblocking agent having an average particle diameter (Coulter method) of 1.0 to 3.0 µm.

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