KR20180101316A - Double-sided adhesive tape - Google Patents

Abstract

It is an object of the present invention to provide a double-faced pressure-sensitive adhesive tape having excellent shear adhesion, which is used for adhesive fixation of components constituting a portable electronic device, adhesive fixation of automobile members, and the like. A double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a substrate, wherein the substrate is made of a foam and has an interlaminar strength of 10 N / 5 mm or more and 30 N / 5 mm or less, Layer is a double-sided pressure-sensitive adhesive tape having a storage elastic modulus G 'at 20 캜 of 2.5 x 10 ⁵ Pa or more and a loss elastic modulus G "at 20 캜 of 2 x 10 ⁵ Pa or more.

Description

Double-Sided Adhesive Tape {DOUBLE-SIDED ADHESIVE TAPE}

The present invention relates to a double-sided pressure-sensitive adhesive tape having excellent shear adhesive strength, which is used for adhesion fixing of parts constituting a portable electronic device, adhesive fixing of automobile members, and the like.

Portable electronic devices, such as portable telephones and personal digital assistants (PDA), are designed to prevent the components from being separated or damaged even when an impact is applied in consideration of falling from the user's fingertips to the feet, Is being studied. Therefore, double-sided pressure-sensitive adhesive tapes used for fixing components to the main body of the apparatus are required to have no separation of parts even when an impact is applied, and also to provide a double-sided pressure-sensitive adhesive tape that does not exert a strong impact on the components.

BACKGROUND ART A double-sided pressure-sensitive adhesive tape having a base made of, for example, a polyolefin foam has been studied as an impact-absorbing tape for fixing a component constituting a portable electronic device to an apparatus main body.

Patent Documents 1 and 2 disclose a shock absorbing tape which is a crosslinked polyolefin resin foam sheet having an acrylic pressure-sensitive adhesive layer laminated and integrated on at least one surface of a base layer and a base layer having a specific crosslinking degree and an aspect ratio of bubbles .

In addition, double-sided adhesive tape is also used for fixing automobile members (e.g., vehicle-use panel) to the automobile body. Double-sided adhesive tape having a base made of a polyolefin foam excellent in impact absorption performance is also used as such double- have.

BACKGROUND ART [0002] In recent years, in applications such as fixing a component in a large portable electronic device or fixing an automobile member, it is necessary to bond a large-sized component or member, As shown in Fig. For this reason, the conventional double-sided pressure-sensitive adhesive tape has a problem that it can not withstand the load in the large shear direction and peels off.

Japanese Patent Application Laid-Open No. 2009-242541 JP-A-2009-258274

It is an object of the present invention to provide a double-faced pressure-sensitive adhesive tape having excellent shear adhesion, which is used for adhesive fixation of components constituting a portable electronic device, adhesive fixation of automobile members, and the like.

A double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a substrate, wherein the substrate is made of a foam and has an interlaminar strength of 10 N / 5 mm or more and 30 N / 5 mm or less, Layer is a double-sided pressure-sensitive adhesive tape having a storage elastic modulus G 'at 20 캜 of 2.5 x 10 ⁵ Pa or more and a loss elastic modulus G "at 20 캜 of 2 x 10 ⁵ Pa or more.

Hereinafter, the present invention will be described in detail.

The present inventors have found that by adjusting the storage elastic modulus G 'and the loss elastic modulus G "of the acrylic pressure-sensitive adhesive layer at 20 ° C. to a specific range in a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a substrate, The inventors of the present invention have found that when the base material is a foamed material, the base material can not withstand the load in the shearing direction and breakage (interlaminar fracture) occurs. It has been found that interlayer fracture of such a substrate can be prevented by adjusting the interlaminar strength of the substrate to a specific range, and the present invention has been accomplished.

The double-sided pressure-sensitive adhesive tape of the present invention has a substrate made of a foam. The foam is not particularly limited as long as it is a foam in which bubbles are present in the resin, but a polyolefin foam is preferable.

The substrate has an interlaminar strength of 10 N / 5 mm or more and 30 N / 5 mm or less.

By adjusting the interlaminar strength of the base material to the above range, it is possible to prevent the base material from being subjected to the load in the shearing direction and to prevent breakage (interlaminar fracture), thereby obtaining a double-sided pressure-sensitive adhesive tape having excellent shear adhesive strength.

When the interlaminar strength of the base material is less than 10 N / 5 mm, if a load in a large shear direction is applied to the double-faced pressure-sensitive adhesive tape, interlaminar fracture of the base material occurs. The interlaminar strength of the substrate is preferably 15 N / 5 mm or more.

If the interlaminar strength of the base material exceeds 30 N / 5 mm, the flexibility of the base material is impaired. The interlayer strength of the substrate is preferably 20 N / 5 mm or less.

The interlaminar strength of the base material can be measured as follows. Fig. 1 is a schematic view showing a method of measuring the interlaminar strength of the base material.

As shown in Fig. 1, a pressure-sensitive adhesive (not shown) was coated on both sides of a substrate (width 5 mm) 1 to a thickness of 50 탆, and one side of the substrate was backed with a PET film having a thickness of 23 탆 And the other side is bonded to the SUS plate 2 and cured for 48 hours to prepare a test sample. Subsequently, the base material 1 is peeled off at a rate of 100 m / min in a direction of 180 ° at 23 ° C and 50% RH, and the peel strength when the base material 1 causes interlayer fracture is taken as the interlaminar strength.

The interlaminar strength of the base material can be adjusted to a desired range based on the density, expansion ratio, crosslinking degree, and stretching ratio of the base material.

The thickness of the substrate is not particularly limited, but the lower limit is preferably 80 占 퐉, and the upper limit is preferably 300 占 퐉. If the thickness of the base material is less than 80 탆, the strength of the base material is lowered, the base material tends to be interlayer-fractured, or the impact resistance of the double-sided pressure-sensitive adhesive tape may be deteriorated. If the thickness of the base material exceeds 300 m, the flexibility of the base material is deteriorated to lower the impact resistance of the double-sided adhesive tape, and the total thickness of the double-sided adhesive tape is increased, It may become unsuitable for applications such as adhesion fixing and adhesive bonding of automobile members. A more preferable lower limit of the substrate thickness is 100 mu m, and a more preferable upper limit is 200 mu m.

The density of the base material is preferably 0.35 g / cm3 or more and 0.7 g / cm3 or less. Since the density of the base material is 0.35 g / cm 3 or more, even when a load in a large shearing direction is applied to the double-faced pressure-sensitive adhesive tape, interlayer fracture of the base material does not occur well. The density of the base material is more preferably 0.45 g / cm 3 or more, and still more preferably 0.5 g / cm 3 or more.

When the density of the base material is 0.7 g / cm 3 or less, the impact resistance of the double-sided pressure-sensitive adhesive tape can be further increased. A more preferable upper limit of the substrate density is 0.6 g / cm 3.

The density of the base material can be measured and measured by using an electronic specific gravity meter (trade name " ED120T ") manufactured by Miraji Co., Ltd. in accordance with JIS K-6767.

The foaming magnification of the base material is preferably 1.2 times lower and 2.8 times higher than the upper limit. Since the expansion ratio of the base material is 1.2 times or more, the flexibility and impact resistance of the double-sided pressure-sensitive adhesive tape can be improved. When the expansion ratio of the base material is 2.8 times or less, it is possible to prevent the base material from being able to withstand a load in the shearing direction and to prevent breakage (interlaminar fracture), thereby obtaining a double-sided pressure-sensitive adhesive tape having excellent shear adhesion. A more preferable lower limit of the expansion ratio of the base material is 1.4 times, and a more preferable upper limit is 2.2 times, more preferably a lower limit is 1.7 times, and a more preferable upper limit is 2 times.

The foaming magnification of the base material can be calculated from the reciprocal of the base material density.

As a method for producing a substrate made of a foamed material having an interlaminar strength of 10 N / 5 mm or more and 30 N / 5 mm or less, a conventionally known method such as a method of foaming after crosslinking the resin composition as a raw material Can be used.

Specifically, for example, when the substrate is a polyolefin-based resin composition, it can be produced by a method having the following steps (1) to (3).

Step (1): A step of obtaining a sheet-shaped polyolefin resin composition by feeding a polyolefin resin, a thermally decomposable foaming agent and other additives to an extruder, melt-kneading the same,

Step (2): Step of crosslinking the sheet-shaped polyolefin resin composition

Step (3): a step of heating the cross-linked polyolefin-based resin composition in a sheet form to foam the thermally decomposable foaming agent and stretching it in one or both directions of the MD direction or the TD direction

As a method for producing a crosslinked polyolefin-based resin foam, it is also possible to produce the crosslinked polyolefin-based resin foam by the method described in International Publication No. 2005/007731.

Examples of the polyolefin-based resin in the step (1) include a polyethylene-based resin, a polypropylene-based resin, and mixtures thereof.

The polyethylene-based resin may be an ethylene homopolymer, but is preferably a polyethylene-? -Olefin copolymer obtained by copolymerizing ethylene with a small amount of? -Olefin, and among these, a linear low density polyethylene is more preferable. By making the polyethylene-based resin a copolymer of ethylene and a small amount of -olefin, the flexibility of the foam can be enhanced and the impact resistance can be further improved.

Examples of the? -Olefin in the polyethylene-? -Olefin copolymer include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, And the like. Of these,? -Olefins having 4 to 10 carbon atoms are preferred.

The preferable lower limit of the? -Olefin in the polyethylene -? - olefin copolymer is 30% by weight, and the lower limit is more preferably 10% by weight.

As the polyethylene-based resin, an ethylene-vinyl acetate copolymer is also preferable. The ethylene-vinyl acetate copolymer is a copolymer containing at least 50% by weight of constituent units derived from ethylene.

The polyethylene-based resin is preferably low in density from the viewpoint of enhancing the flexibility of the foam and enhancing the impact resistance. The density of the polyethylene resin is preferably 0.920 g / cm3 or less, more preferably 0.880 to 0.915 g / cm3, and even more preferably 0.885 to 0.910 g / cm3.

The density is a value measured in accordance with ASTM D792.

Examples of the polypropylene-based resin include a propylene homopolymer and a propylene-? -Olefin copolymer containing 50% by weight or more of a constituent unit derived from propylene. These may be used alone or in combination of two or more.

Examples of the? -Olefin in the propylene-? -Olefin copolymer include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, . Among them, an? -Olefin having 6 to 12 carbon atoms is preferable.

The polyolefin-based resin is preferably a polyethylene-based resin, a polypropylene-based resin, or a mixture thereof polymerized by using a metallocene compound, a chi-gracilanating compound, or a chromium oxide compound as a catalyst from the viewpoint of improving flexibility and impact- , And more preferably a linear low density polyethylene.

The metallocene compound is preferably a compound such as a bis (cyclopentadienyl) metal complex having a structure in which a transition metal is sandwiched between? Electrostatic unsaturated compounds. Concretely, for example, a tetravalent transition metal such as titanium, zirconium, nickel, palladium, hafnium and platinum, and one or more cyclopentadienyl rings or derivatives thereof as a ligand And the like.

Such a metallocene compound has uniform properties of active points and each active point has the same activity. As a result, the polymer synthesized by using the above metallocene compound has high uniformity in molecular weight, molecular weight distribution, composition, composition distribution, and the like. Therefore, a sheet containing a polymer synthesized using the metallocene compound is crosslinked In one case, crosslinking proceeds uniformly. Since the homogeneously crosslinked sheet is easily stretched uniformly, it is easy to make the thickness of the crosslinked polyolefin-based resin foam uniform.

Examples of the ligand include cyclic compounds such as cyclopentadienyl ring and indenyl ring. The cyclic compound may have a substituent such as a hydrocarbon group, a substituted hydrocarbon group or a hydrocarbon-substituted metalloid group. Examples of the hydrocarbon group include a methyl group, an ethyl group, various propyl groups, various butyl groups, various amyl groups, various hexyl groups, 2-ethylhexyl groups, various heptyl groups, various octyl groups, various nonyl groups, , Various cetyl groups, phenyl groups and the like. Here, the term " various " means various isomers such as n-, sec-, tert-, iso- and the like.

Further, a polymer obtained by polymerizing the cyclic compound as an oligomer may be used as a ligand.

In addition to the π-electropneumatic compound, a monovalent anion ligand such as chlorine or bromine, a divalent anion chelating ligand, a hydrocarbon, an alkoxide, an arylamide, an aryloxide, an amide, an arylamide, a phosphide or an arylphosphide .

Examples of the metallocene compound containing the tetravalent transition metal or the ligand include cyclopentadienyltitanium tris (dimethylamido), methylcyclopentadienyltitanium tris (dimethylamido), bis (cyclopentadienyl) Nyl) titanium dichloride, dimethylsilyltetramethylcyclopentadienyl-t-butylamide zirconium dichloride, and the like.

The above metallocene compound exerts its action as a catalyst in the polymerization of various olefins by combining with a specific co-catalyst (co-catalyst). Examples of the cocatalyst include methylaluminoxane (MAO), boron-based compounds, and the like. The use ratio of the cocatalyst to the metallocene compound is preferably from 10 to 100 million moles, more preferably from 50 to 5,000 moles.

When a polyethylene resin, an ethylene-vinyl acetate copolymer, or a mixture thereof obtained by using the above metallocene compound as a catalyst is used, the content thereof is preferably 40% by weight or more, more preferably 50% by weight or less based on the total weight of the polyolefin- Or more, more preferably 60 wt% or more, and particularly preferably 100 wt%. When the content of the polyethylene-based resin, ethylene-vinyl acetate copolymer or mixture thereof obtained by using the metallocene compound as a catalyst is 40% by weight or more, a high compressive strength can be obtained even when the thickness of the polyolefin foam is small have.

The chiglitanium compound is a triethylaluminum-titanium tetrachloride solid composite comprising a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound and treating with various electron donors and electron acceptors, an organoaluminum compound, (Japanese Unexamined Patent Application Publication No. 56-100806, Japanese Unexamined Patent Application Publication No. 56-120712, Japanese Unexamined Patent Publication No. 58-104907), a method of combining titanium tetrachloride and various kinds of magnesium halide A method of using a supported catalyst in which an electron donor is brought into contact (JP-A-57-63310, JP-A-63-43915, JP-A-63-83116) .

The polyolefin-based resin composition may contain an optional component such as a resin other than the polyolefin-based resin described above.

Examples of the optional components include resins other than polyolefin-based resins and rubbers. These optional components are preferably contained in a total amount less than that of the polyolefin-based resin. Specifically, the amount is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, based on 100 parts by weight of the polyolefin-based resin.

The thermally decomposable foaming agent is not particularly limited and includes, for example, azodicarbonamide, N, N'-dinitrosopentamethylenetetramine, p-toluenesulfonylsemicarbazide, and the like. Of these, azodicarbonamide is preferred. The thermally decomposable foaming agent may be used singly or in combination of two or more kinds.

The content of the thermally decomposable foaming agent is preferably 1 to 12 parts by weight, more preferably 1 to 8 parts by weight, per 100 parts by weight of the polyolefin resin. When the content of the thermally decomposable foaming agent is within the above range, the foamability of the polyolefin-based resin composition is improved, a polyolefin-based resin foam having a desired expansion ratio and interlaminar strength is easily obtained, and tensile strength and compressive recovery Can be improved.

Examples of the other additives include a decomposition temperature regulator, a crosslinking aid, and an antioxidant.

The decomposition temperature adjusting agent is compounded by adjusting the surface condition of the foam or the like by lowering the decomposition temperature or accelerating the decomposition rate of the thermally decomposable foaming agent. Examples of the decomposition temperature adjusting agent include zinc oxide, zinc stearate, urea and the like.

The content of the decomposition temperature adjusting agent relative to 100 parts by weight of the polyolefin-based resin is preferably 0.01 to 5 parts by weight.

The crosslinking aid is added to the polyolefin resin so as to reduce the amount of ionizing radiation to be irradiated in the crosslinking of the polyolefin resin to be described later and to prevent cutting and deterioration of resin molecules caused by irradiation with ionizing radiation, do.

Examples of the crosslinking aid include polyfunctional monomers and the like. Specific examples include trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimellitic acid triallyl ester, 1,2,4-benzenetricarboxylic acid triallyl ester, and triallyl isocyanurate. A compound having three functional groups in the molecule, a compound having one functional group such as 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, , Diallyl phthalate, diallyl terephthalate, diallyl isophthalate, ethylvinylbenzene, neopentyl glycol dimethacrylate, lauryl methacrylate, stearyl methacrylate, and the like.

These crosslinking assistants may be used alone or in combination of two or more.

The amount of the crosslinking aid to be added is preferably from 0.2 to 10 parts by weight, more preferably from 0.3 to 5 parts by weight, and still more preferably from 0.5 to 5 parts by weight, based on 100 parts by weight of the polyolefin resin. By adding the crosslinking aid in an amount of 0.2 parts by weight or more, a foam having desired degree of crosslinking can be stably obtained. When the addition amount of the crosslinking aid is 10 parts by weight or less, the degree of crosslinking of the foam can be easily controlled.

The antioxidant is compounded to prevent oxidation deterioration due to heat. Examples of the antioxidant include phenol-based antioxidants such as 2,6-di-t-butyl-p-cresol and the like.

Examples of the method of crosslinking the polyolefin-based resin composition in the step (2) include a method of irradiating the polyolefin-based resin composition with ionizing radiation such as electron beam,? -Ray,? -Ray and? -Ray, A method in which an organic peroxide is mixed in advance when the resin composition is formed and then the polyolefin resin composition is heated to decompose the organic peroxide. These methods may be used alone or in combination of two or more, but from the viewpoint of homogeneously crosslinking, a method of irradiating with ionizing radiation is preferable.

In the method for irradiating the ionizing radiation, it is preferable that the dose of the ionizing radiation is adjusted so that the gel fraction is 5 to 45% by weight. The specific dose is preferably 0.5 to 20 Mrad, more preferably 3 to 12 Mrad.

Examples of the organic peroxide in the method of previously compounding the organic peroxide with the resin composition include 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1- Bis (t-butylperoxy) cyclohexane, and the like. These may be used singly or in combination of two or more kinds.

The amount of the organic peroxide to be added is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 3 parts by weight per 100 parts by weight of the polyolefin resin. When the addition amount of the organic peroxide is in the above range, crosslinking of the resin composition is easy to proceed, and the amount of decomposition residue of the organic peroxide present in the obtained polyolefin foam can be suppressed.

The method of foaming the polyolefin-based resin composition in the step (3) is not particularly limited, and examples thereof include a method of heating the polyolefin-based resin composition by hot air, a method of heating by infrared rays, , A method of heating by an oil bath, and the like, and these may be used in combination.

The foaming method of the polyolefin resin composition is not limited to the method using the thermal decomposition type foaming agent, and physical foaming with butane gas or the like may be used.

Examples of the method for stretching the polyolefin-based resin composition in the step (3) include a method in which a polyolefin-based resin composition is foamed to obtain a foam, followed by stretching, and a method in which a polyolefin-based resin composition is stretched while foaming . When the polyolefin resin composition is subjected to stretching after foaming by obtaining a foam, it is preferable that the foam is continuously stretched while keeping the molten state at the time of foaming without cooling the foam. However, The foam may be stretched after heating and melting or softening.

The draw ratio of the polyolefin-based resin composition in the MD direction is preferably 1.1 to 3.0 times, more preferably 1.7 to 2.8 times. When the stretching magnification of the polyolefin-based resin composition in the MD direction is set to the lower limit value or more, flexibility and tensile strength of the polyolefin-based resin composition become easy to be improved. By setting the stretching magnification to not more than the upper limit value, it is prevented that the base material is broken during stretching, the foaming gas escapes from the resin composition during foaming and the foaming magnification is lowered, so that the flexibility and tensile strength of the foam become good, And it becomes easy to be uniform. The polyolefin-based resin composition may also be stretched in the TD direction at a draw ratio in the above range.

Here, the MD direction (Machine Direction) refers to the extrusion direction when the polyolefin foam is extruded in the form of a sheet, and the TD direction (Transverse Direction) refers to the direction perpendicular to the MD direction.

The acrylic pressure-sensitive adhesive layer of at least one of the acrylic pressure-sensitive adhesive layers has a storage elastic modulus G 'at 20 ° C of 2.5 x 10 ⁵ Pa or more and a loss elastic modulus G "at 20 ° C of 2 x 10 ⁵ Pa or more.

By adjusting the storage elastic modulus G 'and the loss elastic modulus G "of the acrylic pressure-sensitive adhesive layer at 20 ° C. to the above-mentioned range, the acrylic pressure-sensitive adhesive layer has an appropriate hardness and an excellent shear adhesive strength can be obtained. In the double-sided pressure-sensitive adhesive tape, if at least one acrylic pressure-sensitive adhesive layer has the storage elastic modulus G 'and the loss elastic modulus G "in the above range, the acrylic pressure-sensitive adhesive layers on both sides may have the same composition or different compositions.

If the storage elastic modulus G 'at 20 DEG C is less than 2.5 x 10 < ⁵ > Pa, the shear adhesive strength of the double-faced pressure sensitive adhesive tape is lowered and the double-faced pressure sensitive adhesive tape peels off if a load in a large shear direction is applied. The storage elastic modulus G 'at 20 ° C is preferably 4.0 × 10 ⁵ Pa or more, more preferably 6.0 × 10 ⁵ Pa or more.

The upper limit of the storage elastic modulus G 'at 20 캜 is not particularly limited, but if it is too high, the acrylic pressure-sensitive adhesive layer tends to be lost and the initial tackiness may be lowered. Therefore, the upper limit is preferably 5.0 x 10 ⁶ Pa, The upper limit is 3.0 x 10 < ⁶ > Pa.

When the loss elastic modulus G "at 20 DEG C is less than 2 x 10 < ⁵ > Pa, the double-sided pressure-sensitive adhesive tape has a reduced shear adhesive strength and a double-sided adhesive tape is peeled off when a load in a large shear direction is applied. a loss modulus G "is preferably not less than 4.0 × 10 ⁵ Pa, and, 6.0 × 10 ⁵ Pa or more is more preferable.

The upper limit of the loss elastic modulus G "at 20 ° C is not particularly limited, but if it is too high, the tackiness of the acrylic pressure-sensitive adhesive layer may be lost and the initial tackiness may be lowered. Therefore, the upper limit is preferably 5.0 × 10 ⁶ Pa, The upper limit is 3.0 x 10 < ⁶ > Pa.

The storage elastic modulus G 'and the loss elastic modulus G "at 20 ° C were measured at a frequency of 10 Hz and a temperature raising rate of 3 ° C / min using a dynamic viscoelasticity measuring device (for example, DVA-200 manufactured by Haitian Corporation) min from -40 ° C to 140 ° C and reading the storage modulus G 'and loss modulus G "at 20 ° C.

As a method of adjusting the storage elastic modulus G 'and the loss elastic modulus G "of the acrylic pressure-sensitive adhesive layer at 20 ° C to a desired range, for example, a method of adjusting the composition, weight average molecular weight, molecular weight distribution and the like of the acrylic copolymer , A method of mixing an acrylic copolymer such as a different composition, a weight average molecular weight and a molecular weight distribution, a method of adjusting a softening point and a content of a tackifier resin, a method of adjusting the degree of crosslinking of the acrylic pressure sensitive adhesive layer and the like.

The acrylic copolymer constituting the acrylic pressure-sensitive adhesive layer is preferably obtained by copolymerizing a monomer mixture containing butyl acrylate and 2-ethylhexyl acrylate.

The preferred content of butyl acrylate in the total monomer mixture is 40 to 80% by weight. If the content of butyl acrylate is less than 40% by weight, the acryl pressure-sensitive adhesive layer becomes too soft and the cohesive force is lowered, and the shear adhesive strength of the double-sided pressure-sensitive adhesive tape may be lowered. If the content of butyl acrylate exceeds 80% by weight, the acryl pressure-sensitive adhesive layer becomes hard and the adhesive strength or tack is lowered, so that the shear adhesive strength of the double-sided pressure-sensitive adhesive tape may be lowered.

The preferable content of 2-ethylhexyl acrylate in the entire monomer mixture is 10 to 40% by weight. If the content of 2-ethylhexyl acrylate is less than 10% by weight, the adhesive strength of the acryl pressure-sensitive adhesive layer is lowered, and the shear adhesive strength of the double-sided pressure-sensitive adhesive tape may be lowered. When the content of 2-ethylhexyl acrylate is more than 40% by weight, the acryl pressure-sensitive adhesive layer becomes too soft and the cohesive force is lowered, so that the shear adhesive strength of the double-sided pressure-sensitive adhesive tape may be lowered.

The monomer mixture may contain other copolymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate if necessary.

Examples of the other polymerizable monomer that can be copolymerized include monomers having an alkyl group of 1 to 3 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, (Meth) acrylic acid alkyl ester having 13 to 18 carbon atoms in the alkyl group such as alkyl (meth) acrylate, tridecyl methacrylate and stearyl (meth) acrylate, hydroxyalkyl (meth) acrylate, glycerin dimethacrylate, ) Functional monomers such as glycidyl acrylate, 2-methacryloyloxyethyl isocyanate, (meth) acrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid and fumaric acid.

In order to obtain the acrylic copolymer by copolymerizing the monomer mixture, the monomer mixture may be subjected to a radical reaction in the presence of a polymerization initiator. As a method of radical reaction of the monomer mixture, that is, a polymerization method, conventionally known methods are used. For example, a solution polymerization (non-point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization .

The polymerization initiator is not particularly limited, and examples thereof include organic peroxides and azo compounds. As the organic peroxide, for example, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxy pivalate, t-butyl peroxypivalate, Hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, T-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy laurate, and the like. As the azo compound, for example, azobisisobutyronitrile, azobiscyclohexanecarbonitrile and the like can be given. These polymerization initiators may be used alone or in combination of two or more.

The weight average molecular weight (Mw) of the acrylic copolymer is preferably 400,000, and the upper limit is preferably 1,000,000. If the weight average molecular weight is less than 400,000, the cohesive force of the acryl pressure-sensitive adhesive layer is lowered, and the shear adhesive strength of the double-stick pressure-sensitive adhesive tape may be lowered. If the weight average molecular weight exceeds 1 million, the adhesive strength of the acryl pressure-sensitive adhesive layer is lowered, and the shear adhesive strength of the double-sided pressure-sensitive adhesive tape may be lowered. A more preferred lower limit of the weight average molecular weight is 500,000, and a more preferable upper limit is 700,000.

In order to adjust the weight average molecular weight to the above range, polymerization conditions such as polymerization initiator and polymerization temperature may be adjusted.

The weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene as measured by Gel Permeation Chromatography (gel permeation chromatography).

The acrylic pressure-sensitive adhesive layer may contain a tackifier resin.

Examples of the tackifier resin include rosin ester resin, hydrogenated rosin resin, terpene resin, terpene phenol resin, coumarone indene resin, alicyclic saturated hydrocarbon resin, C5 petroleum resin, C9 petroleum resin Resin, a C5-C9 copolymer based petroleum resin, and the like. These tackifier resins may be used alone or in combination of two or more.

The content of the tackifier resin is not particularly limited, but a preferable lower limit is 10 parts by weight and a preferable upper limit is 60 parts by weight based on 100 parts by weight of the acrylic copolymer. If the content of the tackifier resin is less than 10 parts by weight, the adhesive strength of the acryl pressure-sensitive adhesive layer is lowered, and the shear adhesive strength of the double-sided pressure-sensitive adhesive tape may be lowered. If the content of the tackifier resin exceeds 60 parts by weight, the acrylic pressure-sensitive adhesive layer becomes hard and the adhesive strength or tack is lowered, so that the shear adhesive strength of the double-sided pressure-sensitive adhesive tape may be lowered.

It is preferable that a cross-linking structure is formed between the main chain of the resin (the acrylic copolymer and / or the tackifier resin) constituting the acrylic pressure-sensitive adhesive layer by adding a crosslinking agent to the acrylic pressure-sensitive adhesive layer.

The crosslinking agent is not particularly limited, and examples thereof include an isocyanate crosslinking agent, an aziridine crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent. Of these, isocyanate-based crosslinking agents are preferred. By adding an isocyanate crosslinking agent to the acryl pressure-sensitive adhesive layer, the isocyanate group of the isocyanate crosslinking agent reacts with the alcoholic hydroxyl group in the resin constituting the acrylic pressure-sensitive adhesive layer, and the crosslinking of the acrylic pressure-sensitive adhesive layer becomes gentle. Therefore, the acrylic pressure-sensitive adhesive layer can disperse the exfoliation stress applied intermittently, and the shear adhesive strength of the double-faced pressure-sensitive adhesive tape is further improved.

The amount of the crosslinking agent to be added is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the acrylic copolymer.

The crosslinking degree of the acrylic pressure-sensitive adhesive layer is preferably from 5 to 40% by weight, more preferably from 10 to 40% by weight, even though the crosslinking degree of the acrylic pressure-sensitive adhesive layer is too high or too low, By weight, and particularly preferably 15 to 35% by weight.

The crosslinking degree of the acrylic pressure-sensitive adhesive layer was measured by taking W1 (g) of the acrylic pressure-sensitive adhesive layer, immersing the acrylic pressure-sensitive adhesive layer in ethyl acetate at 23 DEG C for 24 hours, filtering the insoluble fractions with a wire mesh of 200 mesh, The residue is vacuum dried to determine the weight W2 (g) of the dried residue, and is calculated by the following formula (1).

Crosslinking degree (% by weight) = 100 x W2 / W1 (One)

The thickness of the acryl pressure-sensitive adhesive layer is not particularly limited, but it is preferable that the thickness of the acrylic pressure-sensitive adhesive layer on one side is 10 to 100 占 퐉. If the thickness of the acryl pressure-sensitive adhesive layer is less than 10 m, the impact resistance or shear adhesion of the double-sided pressure-sensitive adhesive tape may be lowered. If the thickness of the acryl pressure-sensitive adhesive layer exceeds 100 占 퐉, the reworkability or re-release property of the double-sided pressure-sensitive adhesive tape may be impaired.

In the double-sided pressure-sensitive adhesive tape of the present invention, the total thickness of the double-sided pressure-sensitive adhesive tape is preferably 50 to 400 탆. If the total thickness of the double-sided pressure-sensitive adhesive tape is less than 50 占 퐉, the impact resistance or shear adhesion strength of the double-sided pressure-sensitive adhesive tape may be lowered. If the total thickness of the double-sided pressure-sensitive adhesive tape exceeds 400 占 퐉, it may become unsuitable for applications such as fixing of components constituting a portable electronic device, adhesion of an automobile member, and the like. A more preferable lower limit of the total thickness of the double-sided pressure-sensitive adhesive tape is 100 m, and a more preferable upper limit is 300 m.

As a method for producing the double-faced pressure-sensitive adhesive tape of the present invention, for example, the following method can be mentioned.

First, a solution of the pressure-sensitive adhesive A is prepared by adding a solvent to an acrylic copolymer, a pressure-sensitive adhesive resin and, if necessary, a crosslinking agent, and the solution of the pressure-sensitive adhesive A is coated on the surface of the substrate, Layer A is formed. Next, the releasing film is superimposed on the formed acrylic pressure-sensitive adhesive layer A in such a state that the release-treated surface faces the acrylic pressure-sensitive adhesive layer A.

Subsequently, a release film separate from the release film was prepared, the solution of the pressure-sensitive adhesive B was coated on the release-treated surface of the release film, and the solvent in the solution was completely dried to remove the acrylic pressure- Thereby forming a laminated film. The obtained laminated film is laminated on the rear surface of the base material on which the acrylic pressure-sensitive adhesive layer A is formed and the acrylic pressure-sensitive adhesive layer B on the back surface of the base material so as to face each other. The double-sided pressure-sensitive adhesive tape having the acrylic pressure-sensitive adhesive layer on both sides of the substrate and the surface of the acrylic pressure-sensitive adhesive layer covered with the release film can be obtained by pressing the laminate with a rubber roller or the like.

In addition, two sets of laminated films were prepared in the same manner, and these laminated films were laminated on both sides of the substrate in such a manner that the acrylic pressure-sensitive adhesive layer of the laminated film was opposed to the substrate so as to produce a laminate, Sensitive adhesive tape having an acryl pressure-sensitive adhesive layer on both sides of the substrate and the surface of the acrylic pressure-sensitive adhesive layer covered with the release film.

The use of the double-faced pressure sensitive adhesive tape of the present invention is not particularly limited, but is preferably used for adhering and fixing components constituting a portable electronic device to the main body of the apparatus, or for adhering and fixing an automobile member to an automobile body . Specifically, the double-faced pressure-sensitive adhesive tape of the present invention can be used for fixation of parts in a large portable electronic device, adhesion fixation of an automobile member (e.g., a vehicle-use panel), and the like.

The shape of the double-faced pressure-sensitive adhesive tape of the present invention in these applications is not particularly limited, and examples thereof include a rectangular shape, a frame shape, a circular shape, an elliptical shape, and a donut shape.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a double-sided pressure-sensitive adhesive tape excellent in shear adhesion, which is used for adhesive fixing of parts constituting a portable electronic device, adhesion fixing of an automobile member,

1 is a schematic view showing a method of measuring the interlaminar strength of a substrate.
2 is a schematic view showing a method of measuring the shear adhesive strength of the double-sided pressure-sensitive adhesive tape.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Preparation of pressure-sensitive adhesive (A)) [

70 parts by weight of butyl acrylate, 27 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, 0.2 part by weight of 2-hydroxyethyl acrylate, and 80 parts by weight of ethyl acetate were added to a reactor equipped with a thermometer, After nitrogen substitution, the reactor was heated to initiate reflux. Subsequently, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added to the reactor. And refluxed at 70 DEG C for 5 hours to obtain a solution of the acrylic copolymer (a). The obtained acrylic copolymer (a) had a weight average molecular weight of 770,000 as determined by GPC method using "2690 Separations Model" manufactured by Water Corporation as a column.

15 parts by weight of a polymerized rosin ester having a softening point of 150 DEG C, 10 parts by weight of terpene phenol having a softening point of 145 DEG C, and 10 parts by weight of a softening point of 70 DEG C were added to 100 parts by weight of the solid content of the acrylic copolymer (a) , 10 parts by weight of rosin ester, 125 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.), and 2.2 parts by weight of an isocyanate-based crosslinking agent (trade name "Colonate L45", trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) were added and stirred to obtain a pressure-sensitive adhesive (A).

(Preparation of pressure-sensitive adhesive (B)) [

(B) was obtained in the same manner as in the case of the pressure-sensitive adhesive (A) except that 15 parts by weight of polymerized rosin ester having a softening point of 130 DEG C, 10 parts by weight of terpene phenol having a softening point of 130 DEG C and 10 parts by weight of rosin ester having a softening point of 100 DEG C were used as the tackifier resin. .

(Preparation of pressure-sensitive adhesive (C)) [

(C) was obtained in the same manner as in the case of the pressure-sensitive adhesive (A) except that 12 parts by weight of polymerized rosin ester having a softening point of 130 DEG C, 10 parts by weight of terpene phenol having a softening point of 150 DEG C and 10 parts by weight of rosin ester having a softening point of 100 DEG C were used as the tackifier resin. .

(Preparation of pressure-sensitive adhesive (D)) [

(C) having a weight-average molecular weight of 670,000 was obtained in the same manner as in the acrylic copolymer (a) except that the amount of 2-ethylhexyl acrylate added was changed to 20 parts by weight and 7 parts by weight of ethyl acrylate was further added. Solution.

Except that 15 parts by weight of polymerized rosin ester having a softening point of 150 DEG C, 10 parts by weight of terpene phenol having a softening point of 130 DEG C and 10 parts by weight of rosin ester having a softening point of 70 DEG C were used as the tackifier resin A pressure-sensitive adhesive (D) was obtained in the same manner as the pressure-sensitive adhesive (A).

(Preparation of pressure-sensitive adhesive (E)) [

Except that the amount of 2-ethylhexyl acrylate added was changed to 15 parts by weight, and 7 parts by weight of ethyl acrylate and 5 parts by weight of vinyl acetate were added. In the same manner as the acrylic copolymer (a) To obtain a solution of the copolymer (d).

Except that 10 parts by weight of polymerized rosin ester having a softening point of 130 DEG C, 8 parts by weight of terpene phenol having a softening point of 130 DEG C and 6 parts by weight of rosin ester having a softening point of 70 DEG C were used as the tackifier resin A pressure-sensitive adhesive (E) was obtained in the same manner as the pressure-sensitive adhesive (A).

(Preparation of pressure-sensitive adhesive (F)) [

A pressure-sensitive adhesive (F) was obtained in the same manner as in pressure-sensitive adhesive (A) except that 15 parts by weight of polymerized rosin ester having a softening point of 150 캜 was used as the pressure-sensitive adhesive resin.

(Preparation of pressure-sensitive adhesive (G)) [

Except that the addition amount of 2-ethylhexyl acrylate was changed to 20 parts by weight and the addition amount of ethyl acrylate was changed to 7 parts by weight and the amount of azobisisobutyronitrile was changed to 0.05 part by weight. To obtain a solution of the acrylic copolymer (f) having a weight average molecular weight of 1,220,000.

Except that 15 parts by weight of polymerized rosin ester having a softening point of 150 DEG C, 10 parts by weight of terpene phenol having a softening point of 150 DEG C and 10 parts by weight of rosin ester having a softening point of 100 DEG C were used as the tackifier resin A pressure-sensitive adhesive (G) was obtained in the same manner as the pressure-sensitive adhesive (A).

(Preparation of pressure-sensitive adhesive (H)) [

A pressure-sensitive adhesive (H) was obtained in the same manner as the pressure-sensitive adhesive (A) except that 10 parts by weight of polymerized rosin ester having a softening point of 150 캜 and 8 parts by weight of rosin ester having a softening point of 100 캜 were used as the tackifier resin.

(Preparation of pressure-sensitive adhesive (I)) [

Butyl acrylate was changed to 77 parts by weight and 20 parts by weight of methyl methacrylate was added instead of 27 parts by weight of 2-ethylhexyl acrylate, the weight average molecular weight (Mw) of the acrylic copolymer A solution of an acrylic copolymer (h) of 60,000 was obtained.

A pressure-sensitive adhesive (I) was obtained in the same manner as in the pressure-sensitive adhesive (A) except that the solution of the obtained acrylic copolymer (h) was used and the pressure-sensitive adhesive resin was not used.

(Preparation of pressure-sensitive adhesive (J)) [

Butyl acrylate was changed to 77 parts by weight and 20 parts by weight of methyl acrylate was added instead of 27 parts by weight of 2-ethylhexyl acrylate to obtain a copolymer having a weight average molecular weight of 60 To obtain a solution of the acrylic copolymer (h) alone.

Except that 15 parts by weight of polymerized rosin ester having a softening point of 150 DEG C, 15 parts by weight of terpene phenol having a softening point of 150 DEG C and 15 parts by weight of rosin ester having a softening point of 100 DEG C were used as the tackifier resin A pressure-sensitive adhesive (J) was obtained in the same manner as the pressure-sensitive adhesive (A).

(Preparation of polyolefin foam (A)) [

100 parts by weight of a linear low density polyethylene (trade name "Exact3027", trade name: Exact3027, density: 0.900 g / cm3) as a polyolefin resin, 2 parts by weight of azodicarbonamide as a thermally decomposable foaming agent, And 0.5 part by weight of 2,6-di-t-butyl-p-cresol as an antioxidant were supplied to an extruder and melt-kneaded at 130 DEG C to obtain a polyolefin resin composition having a thickness of about 0.3 mm, Respectively.

Next, the elongated sheet-like polyolefin-based resin composition was irradiated with electron beams having an acceleration voltage of 500 kV at 4.5 Mrad on both sides thereof and crosslinked, and then continuously fed into a foaming furnace maintained at 250 占 폚 by hot air and an infrared heater, And stretching the polyolefin foam (A) having a thickness of 0.14 mm by stretching the polyolefin foam (A) at a stretching ratio of MD of 1.5 and a stretch ratio of TD of 2.0 while foaming. The density and interlaminar strength of the obtained foam were measured. The density of the polyolefin foam was measured and calculated by using an electronic specific gravity meter (trade name " ED120T ") manufactured by Miraji Co., Ltd. in accordance with JIS K-6767. The interlayer strength of the polyolefin foam was measured by the measuring method shown in Fig. 1 as described above.

(Preparation of polyolefin foam (B)) [

A polyolefin foam (B) was obtained in the same manner as in the production of the polyolefin foam (A) except that the draw ratio of TD was changed to 2.2 times. The density and interlaminar strength of the obtained foam were measured.

(Preparation of Polyolefin Foam (C)) [

A polyolefin foam (C) was obtained in the same manner as in the production of the polyolefin foam (A), except that the amount of the azodicarbonamide to be blended was changed to 2.2 parts by weight and the TD stretching ratio was changed to 1.8. The density and interlaminar strength of the obtained foam were measured.

(Preparation of Polyolefin Foam (D)) [

A polyolefin foam (D) was obtained in the same manner as in the production of the polyolefin foam (A) except that the amount of the azodicarbonamide to be blended was 1.9 parts by weight and the stretching ratio of TD was 1.9 times. The density and interlaminar strength of the obtained foam were measured.

(Preparation of polyolefin foam (E)) [

A polyolefin foam (E) was obtained in the same manner as in the production of the polyolefin foam (A) except that the amount of the azodicarbonamide to be blended was changed to 3 parts by weight and the stretching magnification of the TD was tripled. The density and interlaminar strength of the obtained foam were measured.

(Preparation of polyolefin foam (F)) [

A polyolefin foam (F) was obtained in the same manner as in the production of the polyolefin foam (A), except that the amount of the azodicarbonamide to be blended was 2.8 parts by weight and the TD stretching ratio was 2.8 times. The density and interlaminar strength of the obtained foam were measured.

(Example 1)

A releasing paper having a thickness of 150 占 퐉 was prepared, a releasing treated surface of the releasing paper was coated with a pressure-sensitive adhesive (J), and dried at 100 占 폚 for 5 minutes to form an acrylic pressure-sensitive adhesive layer having a thickness of 50 占 퐉. This acrylic pressure-sensitive adhesive layer was bonded to the surface of the polyolefin foam (A). Then, in the same manner, the same acrylic pressure-sensitive adhesive layer as above was bonded to the opposite surface of the polyolefin foam. Thereafter, curing was carried out by heating at 40 DEG C for 48 hours. Thus, a double-sided pressure-sensitive adhesive tape having a total thickness shown in Table 1 covered with a release paper having a thickness of 150 mu m was obtained.

The acrylic pressure-sensitive adhesive layer was measured at -40 ° C to 140 ° C at a frequency of 10 Hz and a temperature raising rate of 3 ° C / min using a dynamic viscoelasticity measuring apparatus (DVA-200 manufactured by Haitian Instrumentation Control Co.) The storage elastic modulus G 'and the loss elastic modulus G "

(Example 2)

Except that the kind of the pressure-sensitive adhesive was changed to the pressure-sensitive adhesive (A) so that the acrylic pressure-sensitive adhesive layer having the storage elastic modulus G 'and the loss elastic modulus G "at 20 ° C as shown in Table 1 was changed to double- I got a tape.

(Example 3)

A double-faced pressure-sensitive adhesive tape was obtained in the same manner as in Example 2 except that the polyolefin foam was changed to polyolefin foam (B) to have the density, thickness and interlaminar strength shown in Table 1.

(Example 4)

A double-faced pressure-sensitive adhesive tape was obtained in the same manner as in Example 3, except that the polyolefin foam was changed to a polyolefin foam (C) so that the polyolefin foam had the density, thickness and interlaminar strength shown in Table 1. [

(Example 5)

Except that the kind of the pressure-sensitive adhesive was changed to the pressure-sensitive adhesive (B) to change to an acrylic pressure-sensitive adhesive layer having a storage elastic modulus G 'and a loss elastic modulus G "at 20 캜 shown in Table 1, I got a tape.

(Example 6)

Except that the pressure-sensitive adhesive (C) was changed to the acrylic pressure-sensitive adhesive layer having the storage elastic modulus G 'and the loss elastic modulus G "at 20 ° C as shown in Table 1, I got a tape.

(Example 7)

By changing the kind of the polyolefin foam to the polyolefin foam (D), the polyolefin foam was changed to have the density, thickness and interlaminar strength shown in Table 1 and the kind of the pressure-sensitive adhesive to the pressure-sensitive adhesive (D) Sensitive adhesive tape was obtained in the same manner as in Example 3, except that the acrylic pressure-sensitive adhesive layer was changed to an acrylic pressure-sensitive adhesive layer having a storage elastic modulus G 'and a loss elastic modulus G'

(Example 8)

By changing the kind of the polyolefin foam to the polyolefin foam (D), the polyolefin foam was changed to have the density, thickness and interlaminar strength shown in Table 1, and the kind of the pressure-sensitive adhesive was changed to the pressure-sensitive adhesive (E) Sensitive adhesive tape was obtained in the same manner as in Example 3, except that the acrylic pressure-sensitive adhesive layer was changed to an acrylic pressure-sensitive adhesive layer having a storage elastic modulus G 'and a loss elastic modulus G'

(Comparative Example 1)

By changing the kind of the polyolefin foam to the polyolefin foam (E), the polyolefin foam was changed to having the density, thickness and interlaminar strength shown in Table 2 and the kind of the pressure-sensitive adhesive to the pressure-sensitive adhesive (F) Sensitive adhesive tape was obtained in the same manner as in Example 3, except that the acrylic pressure-sensitive adhesive layer was changed to an acrylic pressure-sensitive adhesive layer having a storage elastic modulus G 'and a loss elastic modulus G'

(Comparative Example 2)

Except that the type of the pressure-sensitive adhesive was changed to the pressure-sensitive adhesive (G) to change the acrylic pressure-sensitive adhesive layer having the storage elastic modulus G 'and the loss elastic modulus G "at 20 ° C as shown in Table 2, I got a tape.

(Comparative Example 3)

A double-faced pressure-sensitive adhesive tape was obtained in the same manner as in Comparative Example 1 except that the polyolefin foam was changed to a polyolefin foam (F), and the polyolefin foam was changed to have the density, thickness and interlaminar strength shown in Table 2.

(Comparative Example 4)

A pressure-sensitive adhesive was prepared in the same manner as in Example 4, except that the pressure-sensitive adhesive was changed to a pressure-sensitive adhesive (H) to change the acrylic pressure-sensitive adhesive layer having a storage elastic modulus G 'and a loss elastic modulus G " I got a tape.

(Comparative Example 5)

Except that the pressure-sensitive adhesive (I) was changed to an acrylic pressure-sensitive adhesive layer having a storage elastic modulus G 'and a loss elastic modulus G "at 20 ° C as shown in Table 2, in the same manner as in Comparative Example 3, I got a tape.

<Evaluation>

The double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Table 1 and Table 2.

(1) Measurement of Shear Adhesion

2 is a schematic view showing a method of measuring the shear adhesive strength of the double-stick adhesive tape.

2, two polycarbonate plates (PC plates) 3 each having a thickness of 2 mm were bonded with a double-faced adhesive tape (1 cm long x 1 cm wide) 4, pressed for 10 seconds at 5 kg, And allowed to stand at 23 占 폚 for 24 hours to prepare test pieces. Then, two polycarbonate plates (PC plates) 3 each having a thickness of 2 mm were peeled off at a rate of 10 mm / min in the front end direction of the double-stick adhesive tape 4 (arrow direction in Fig. 2) The maximum value of the peeling force at the time of peeling was regarded as shear adhesion.

A case where the shear adhesive strength was 175 N / cm 2 or more was evaluated as?, A case where it was 100 N / cm 2 or more and less than 175 N / cm 2 as?, And a case where the shear adhesion was less than 100 N / Further, the peeling state was observed to evaluate whether the peeling mode was interface peeling or interlayer peeling.

Industrial availability

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a double-sided pressure-sensitive adhesive tape excellent in shear adhesion, which is used for adhesive fixing of parts constituting a portable electronic device, adhesion fixing of an automobile member,

1: substrate
2: SUS plate
3: Polycarbonate plate (PC plate) having a thickness of 2 mm
4: Double-sided adhesive tape

Claims (7)

A double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a substrate,
The substrate is made of a foam, and has an interlaminar strength of 10 N / 5 mm or more and 30 N / 5 mm or less,
Wherein the at least one acrylic pressure-sensitive adhesive layer has a storage elastic modulus G 'at 20 ° C of 2.5 x 10 ⁵ Pa or more and a loss elastic modulus G "at 20 ° C of 2 x 10 ⁵ Pa or more. The method according to claim 1,
Wherein the double-sided pressure-sensitive adhesive tape has a total thickness of 50 to 400 占 퐉. 3. The method according to claim 1 or 2,
Wherein the thickness of the acrylic pressure-sensitive adhesive layer on one side is 10 to 100 占 퐉. The method according to claim 1, 2, or 3,
Wherein the foam is a polyolefin foam. The method according to claim 1, 2, 3, or 4,
Wherein the density of the substrate is 0.35 g / cm3 or more and 0.7 g / cm3 or less. The method of claim 1, 2, 3, 4, or 5,
Wherein the adhesive tape is used for adhering and fixing a component constituting a portable electronic device to an apparatus main body. The method of claim 1, 2, 3, 4, or 5,
Wherein the adhesive tape is used for adhering and fixing an automobile member to an automobile body.

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