Adhesive tape protected with release film

Abstract

To provide an adhesive tape protected by a release film capable of suppressing the outflow of an adhesive.SOLUTION: There is provided an adhesive tape protected by a release film composed of an adhesive tape and a set of release films for sandwiching the adhesive tape, wherein the adhesive tape has a shear storage elastic modulus G' (23°C) at 23°C of 1.0×106 Pa or less, a shear storage elastic modulus G' (130°C) at 130°C of 3.0×104 Pa or more, a moisture vapor transmission rate at a thickness of 50 μm of 100 g / m2 24hr or less and a dielectric constant at 10 kHz of 3 or less and a thickness of 1 μm or more and 300 μm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an adhesive tape protected with a release film. [Background technology]

[0002] In portable electronic devices such as mobile phones and personal digital assistants (PDAs), adhesive tapes are used to fix components to housings, etc. (For example, Patent Documents 1 and 2). Adhesive tapes are also used to fix in-vehicle electronic device components, such as in-vehicle panels, to vehicle bodies. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-242541 A [Patent Document 2] JP 2009-258274 A Summary of the Invention [Problem to be solved by the invention]

[0004] Display devices such as liquid crystal displays are manufactured by laminating multiple optical components, and non-support type transparent adhesive tape (OCA) is used to bond these optical components. Conventionally, acrylic adhesives have been used for OCA from the viewpoint of transparency, but because optical components are vulnerable to moisture and static electricity, adhesives with low moisture permeability and low dielectric properties are required. Therefore, rubber-based adhesives are being considered as adhesives with low moisture permeability and low dielectric properties.

[0005] On the other hand, OCA is manufactured with release films laminated on both sides of the adhesive tape, and after punching out to the desired shape at the manufacturing site, it is stacked and stored. In this case, if a rubber-based adhesive is used for the adhesive tape, the adhesive may seep out to the outside of the release film due to the pressure during punching, or the adhesive may gradually seep out to the outside of the release film due to the weight or dead weight of the stacked adhesive tapes, and get between the release films of the stacked adhesive tapes, causing contamination.

[0006] An object of the present invention is to provide an adhesive tape protected with a release film that can suppress the seepage of the adhesive. [Means for solving the problem]

[0007] The present invention provides an adhesive tape protected by a release film, the release film comprising an adhesive tape and a pair of release films sandwiching the adhesive tape, the adhesive tape having a shear storage modulus G'(23°C) of 1.0×10 6 Pa or less, and the shear storage modulus G'(130°C) at 130°C is 3.0 x 10 4 Pa or more, and the pressure-sensitive adhesive tape has a moisture permeability of 100 g / m when it is 50 μm thick. 2 The adhesive tape has a dielectric constant of 3 or less at 10 kHz, and is an adhesive tape protected with a release film having a thickness of 1 μm or more and 300 μm or less. The present invention will be described in detail below.

[0008] As a result of intensive research, the inventors have found that the lower the shear storage modulus G' of the adhesive at high temperatures, the greater the long-term fluidity, that is, the more likely the adhesive is to ooze out. In the case of conventional adhesive tapes using rubber-based adhesives, the shear storage modulus G' decreases at high temperatures, so that the adhesive is more likely to ooze out of the release film during storage. Based on this knowledge, the inventors have conducted research and found that by setting the shear storage modulus at 23°C and the shear storage modulus at 130°C of an adhesive tape having a specific moisture permeability and dielectric constant within a specific range, an adhesive tape that is less likely to ooze out and has excellent adhesive strength can be obtained even though it uses an adhesive having rubber properties, and have completed the present invention.

[0009] The adhesive tape protected by a release film of the present invention comprises an adhesive tape and a pair of release films that sandwich the adhesive tape. By allowing the pressure-sensitive adhesive tape to satisfy the shear storage modulus described below, the pressure-sensitive adhesive tape of the present invention can be made to be one that is less likely to seep out to the outside of the release film.

[0010] In the present invention, the pressure-sensitive adhesive tape has a shear storage modulus G'(23°C) of 1.0 x 10 6 Pa or less. When the shear storage modulus G' at 23°C of the pressure-sensitive adhesive tape is in the above range, the tape can be attached to an adherend with sufficient adhesive strength at room temperature. From the viewpoint of further improving the adhesive strength at room temperature, the preferable upper limit of G'(23°C) is 8.0 × 10 5 Pa, more preferably 5.0×10 5 The lower limit of the G'(23°C) is not particularly limited, but is 1.0 x 10 Pa from the viewpoint of adhesive strength. 4 It is preferable that the G'(23°C) is 1 Pa. The above G'(23°C) can be adjusted by the type of adhesive used in the adhesive tape. The above G'(23°C) can be obtained by the following method. A measurement sample is prepared by laminating adhesive tape to a thickness of 1000 μm. The dynamic viscoelasticity spectrum of the measurement sample is measured from −50° C. to 200° C. using a viscoelasticity spectrometer (e.g., DVA-200 manufactured by IT Measurement & Control Co., Ltd.) under conditions of 5° C. / min and 1 Hz in a slow heating shear deformation mode, and the storage modulus at 23° C. can be obtained.

[0011] In the present invention, the pressure-sensitive adhesive tape has a shear storage modulus G'(130°C) of 3.0 × 10 4 Pa or more. The shear storage modulus at high temperatures correlates with long-term fluidity, and the lower the shear storage modulus at high temperatures, the greater the long-term fluidity, i.e., the more easily the adhesive seeps out of the release film. By setting the shear storage modulus at 130°C within the above range, the adhesive tape protected by the release film of the present invention can be prevented from seeping out of the release film even when the adhesive tape is stored for a long period of time. The preferable lower limit of the above G'(130°C) is 5.0 x 10 4 Pa, more preferably the lower limit is 1.0×10 5 The upper limit of G'(130°C) is not particularly limited, but is preferably 1.0 x 10 Pa from the viewpoint of ease of handling. 6 It is preferable that the G'(130°C) is 1 Pa. The above G'(130°C) can be adjusted by the type of adhesive used in the adhesive tape. The above G'(130°C) can be obtained as the storage modulus at 130°C when the dynamic viscoelasticity spectrum is measured in the same manner as for the above G'(23°C).

[0012] In the pressure-sensitive adhesive tape protected by a release film of the present invention, the pressure-sensitive adhesive tape has a moisture permeability of 100 g / m when the tape has a thickness of 50 μm. 2 Less than 24 hours. When the pressure-sensitive adhesive tape has a thickness of 50 μm, the pressure-sensitive adhesive tape can be suitably used for fixing components that are vulnerable to moisture, such as components of electronic devices. The preferred upper limit of the pressure-sensitive adhesive tape is 80 g / m 224hr, more preferable upper limit is 50g / m 2 The lower limit of the moisture permeability is not particularly limited, and the lower the better. 2 The moisture permeability is limited to about 24 hours. The moisture permeability can be adjusted by the type of adhesive used in the adhesive tape. The moisture permeability can be obtained by measuring under conditions of 40° C. and 90% RH using a water vapor transmission rate measuring device (for example, PERMATRAN-W 1 / 50 manufactured by MOCON).

[0013] In the pressure-sensitive adhesive tape protected with a release film of the present invention, the pressure-sensitive adhesive tape has a dielectric constant of 3 or less at 10 kHz. By setting the dielectric constant at 10 kHz of the adhesive tape within the above range, the adhesive tape can exhibit sufficient insulation to fix electronic components that are weak against electricity. The upper limit of the dielectric constant at 10 kHz is preferably 2.8, and more preferably 2.5. The lower limit of the dielectric constant at 10 kHz is not particularly limited, but is substantially limited to about 2.0. The dielectric constant at 10 kHz can be adjusted by the type of adhesive used in the adhesive tape. The dielectric constant at 10 kHz can be measured at 23° C. using a measuring device consisting of an LCR meter (e.g., E4980AL manufactured by Keysight Corporation), a capacitance type dielectric constant / dielectric loss tangent measuring system (e.g., DPT-2141-01 manufactured by Keycom Corporation), and a constant temperature, high temperature and high humidity chamber (e.g., SH-242 manufactured by ESPEC Corporation).

[0014] The pressure-sensitive adhesive tape preferably has a G'(23°C) / G'(130°C)<15. The difference between G'(130°C) and G'(23°C) of the adhesive tape is small, in other words, G' is not easily decreased even at high temperatures, so that the adhesive tape can be further prevented from bleeding out of the release film. G'(23°C) / G'(130°C) of the adhesive tape is more preferably less than 10, and even more preferably less than 8. There is no particular lower limit for G'(23°C) / G'(130°C) of the adhesive tape, and the smaller the better, but the practical limit is about 2. G'(23°C) / G'(130°C) of the adhesive tape can be adjusted depending on the type of adhesive.

[0015] In the present invention, the adhesive constituting the adhesive tape is not particularly limited, and examples thereof include rubber-based adhesives, silicon-based adhesives, acrylic-based adhesives, urethane-based adhesives, etc. Among them, rubber-based adhesives are preferred because they satisfy the above moisture permeability and dielectric constant at 10 kHz and are easily available.

[0016] The rubber-based pressure-sensitive adhesive is preferably a radial type styrene-based elastomer. A radial styrene elastomer is a branched styrene block copolymer having a structure in which multiple styrene block copolymers (styrene elastomers) protrude radially from the coupling agent. The styrene block copolymer is composed of hard and soft segments, and the shear storage modulus G' at high temperatures can be increased by increasing the content of the hard segments. In addition, the styrene block copolymer has a crosslinked structure in which multiple radial protrusions are formed, which suppresses the loosening of the molecules at high temperatures, and therefore the shear storage modulus G' at high temperatures can be further increased. Furthermore, when the molecular weight of the hard segment of a styrene block copolymer is increased, the viscosity becomes too high, making it impossible to manufacture an adhesive tape by a coating method. However, by using a radial styrene elastomer, the viscosity can be kept low enough to be manufactured by a coating method even when the molecular weight of the hard segment is increased.

[0017] The radial styrene-based elastomer has a structure represented by the general formula (AB)nC. In the above general formula, A represents an aromatic alkenyl polymer block (hard segment), B represents a conjugated diene polymer block (soft segment), AB represents a styrene-based block copolymer, C represents a component derived from a coupling agent, and n represents an integer of 3 or more. n is preferably 4 or more in order to further suppress bleeding out of the release film of the pressure-sensitive adhesive tape. There is no particular upper limit for n, but it is usually 8 or less in order to suppress gelation of the radial styrene-based elastomer. The styrene-based block copolymer refers to a diblock structure in which one hard segment and one soft segment are bonded together.

[0018] The aromatic alkenyl polymer block represented by A is a repeating unit derived from an aromatic alkenyl compound. Examples of the aromatic alkenyl compound include styrene, tert-butylstyrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1,1-diphenylethylene, vinylnaphthalene, vinylanthracene, N,N-diethyl-p-aminoethylstyrene, vinylpyridine, etc. Among these, styrene is preferred because it is easily available industrially.

[0019] The conjugated diene polymer block represented by B is a repeating unit derived from a conjugated diene compound. Examples of the conjugated diene compound include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-octadiene, 1,3-hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, myrcene, and chloroprene. These conjugated diene compounds may be used alone or in combination of two or more. Among them, 1,3-butadiene and isoprene are preferred because they have high polymerization reactivity and are easily available industrially.

[0020] Examples of the styrene-based block copolymer include styrene-ethylene-propylene-styrene-based block copolymer (SEPS), hydrogenated styrene-butadiene rubber (HSBR), styrene-ethylene-butylene-styrene-based block copolymer (SEBS), styrene-ethylene-propylene block copolymer (SEP), styrene-ethylene-butylene block copolymer (SEB), styrene-isoprene block copolymer (SI), styrene-isoprene-styrene-based block copolymer (SIS), styrene-butadiene block copolymer (SB), and styrene-butadiene-styrene-based block copolymer (SBS), as well as combinations thereof. Among these, SEBS is preferred because it can increase the shear storage modulus at higher temperatures.

[0021] The styrene-based block copolymer preferably has a content of the aromatic alkenyl polymer block of 50% by weight or less. By setting the content of the aromatic alkenyl polymer block in the styrene-based block copolymer within the above range, a rubber-based pressure-sensitive adhesive having an excellent balance between the shear storage modulus at high temperature and the adhesive strength at room temperature can be obtained. The upper limit of the content of the aromatic alkenyl polymer block in the styrene-based block copolymer is more preferably 35% by weight, and even more preferably 20% by weight. The lower limit of the content of the aromatic alkenyl polymer block in the styrene-based block copolymer is not particularly limited, but is preferably 5% by weight from the viewpoint of further preventing bleeding of the pressure-sensitive adhesive.

[0022] From the viewpoint of increasing optical colorless transparency, the hydrogenation rate of the styrene-based block copolymer is preferably 95% or more, and more preferably 96% or more. The hydrogenation rate of the styrene-based block copolymer is usually 100% or less.

[0023] The coupling agent which is the raw material of the component derived from the coupling agent represented by C above is a polyfunctional compound which radially bonds the styrene-based block copolymer. Examples of the coupling agent include silane compounds such as halogenated silane and alkoxysilane, tin compounds such as tin halides, epoxy compounds such as polycarboxylate and epoxidized soybean oil, acrylic esters such as pentaerythritol tetraacrylate, and divinyl compounds such as epoxysilane and divinylbenzene. More specific examples include trichlorosilane, tribromosilane, tetrachlorosilane, tetrabromosilane, methyltrimethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrachlorotin, and diethyl adipate.

[0024] The molecular weight of the radial styrene elastomer is not particularly limited, but the preferred lower limit is 50,000, and the more preferred lower limit is 100,000. By having the molecular weight of the radial styrene elastomer in the above range, the adhesive strength and handling properties of the resulting adhesive tape can be further improved. The upper limit of the molecular weight is not particularly limited, and the larger it is, the more the adhesive can be prevented from bleeding out, but the higher the molecular weight, the higher the viscosity increases, so the limit that can actually be produced is about 700,000.

[0025] The pressure-sensitive adhesive tape preferably contains the radial styrene-based elastomer and a polymer having a crosslinkable functional group. By blending a polymer having a crosslinkable functional group with a radial styrene-based elastomer, the crosslinkable functional group crosslinks the radial styrene-based elastomer and suppresses the flow of the radial styrene-based elastomer, so that it is possible to further suppress the bleeding out of the release film of the pressure-sensitive adhesive tape. In addition, by blending a polymer having a crosslinkable functional group, it is possible to suppress the elongation of the radial styrene-based elastomer during processing, so that it is also possible to suppress deformation due to pressure when punching the pressure-sensitive adhesive tape.

[0026] The polymer having a crosslinkable functional group is not particularly limited as long as it has a crosslinkable functional group, and examples thereof include amine-modified SEBS, maleic acid-modified SEBS, styrene-acrylic copolymer, etc. Among these, amine-modified SEBS is preferred because of its compatibility with the base resin.

[0027] The content of the polymer having a crosslinkable functional group is preferably 5 parts by weight or more based on 100 parts by weight of the radial styrene-based elastomer. By setting the content of the polymer having a crosslinkable functional group within the above range, the radial styrene-based elastomer can be sufficiently crosslinked, and the bleeding out of the release film of the adhesive tape and deformation during punching can be suppressed. A more preferable lower limit of the content of the polymer having a crosslinkable functional group is 8 parts by weight, and an even more preferable lower limit is 10 parts by weight. The upper limit of the content of the polymer having a crosslinkable functional group is not particularly limited, but is preferably 50 parts by weight from the viewpoint of compatibility with the base resin and from the viewpoint of suppressing a decrease in adhesion due to an increase in gel fraction and a hardening of the paste.

[0028] In the present invention, the pressure-sensitive adhesive tape has an SP value of 8.5 or less, and may contain a softener that is liquid at 23°C. By blending the softener, the adhesive strength and water vapor barrier properties of the obtained pressure-sensitive adhesive tape at room temperature can be further improved. In addition, the radial styrene-based elastomer is poorly compatible with additives usually used in pressure-sensitive adhesive tapes, so there is a problem that the transparency decreases. However, since the softener has the above SP value, it is easily compatible with the conjugated diene polymer block in the styrene-based block copolymer, so that even when a radial styrene-based elastomer is used as a rubber-based adhesive, the decrease in transparency of the obtained pressure-sensitive adhesive tape can be suppressed. Examples of the softener include polybutene, polyisoprene, and paraffin-based oil. Among them, polybutene is preferred because it bleeds less onto the adherend surface over time. Note that while the softener improves the adhesive strength and water vapor barrier properties at room temperature, if used in an excessive amount, it may reduce the shear storage modulus at high temperatures. Therefore, when more importance is placed on suppressing the bleeding of the adhesive than on the adhesive strength and water vapor barrier properties at room temperature, it is preferable to use as little as possible. In this specification, the SP value is called the solubility parameter and is an index that can express the ease of solubility. In this specification, the Fedors method (RF Fedors, Polym. Eng. Sci., 14(2), 147-154(1974)) is used to calculate the SP value.

[0029] Examples of softeners that satisfy the above SP value include polybutene, polyisoprene, paraffin oil, etc. Among them, polybutene is preferred because it is highly compatible with the radial styrene elastomer and can further suppress the decrease in transparency.

[0030] The content of the softener is not particularly limited, but a preferred upper limit relative to 100 parts by weight of the radial styrene-based elastomer is 100 parts by weight, and a more preferred upper limit is 50 parts by weight. As described above, the higher the content of the softener, the better the adhesive strength and water vapor barrier property at room temperature, but the lower the exudation suppression property, so by keeping the content of the softener within the above range, a pressure-sensitive adhesive tape with an excellent balance between adhesive strength and water vapor barrier property at room temperature and exudation suppression property can be obtained.

[0031] In the present invention, the pressure-sensitive adhesive tape preferably contains a tackifier resin having an SP value of 7.5 to 9.0 and a softening point of 80° C. or higher. By blending a tackifier resin having a softening point of 80°C or higher in the adhesive tape, the adhesive strength at high temperatures can be further improved. In addition, by having the SP value of the tackifier resin within the above range, the tackifier resin is compatible with the radial styrene-based elastomer, so that the decrease in transparency of the resulting adhesive tape can be suppressed. The upper limit of the softening point of the tackifier resin is not particularly limited, but is preferably 140°C in consideration of the temperature at which it is used. The softening point can be measured in accordance with JIS K2207.

[0032] The tackifier resin may be, for example, a natural product-based tackifier resin containing an aromatic ring. Among the tackifier resins containing an aromatic ring, the natural product-based tackifier resin has an SP value of 9.0 or less, and is therefore compatible with the aromatic alkenyl polymer block in the radial styrene-based elastomer, and can suppress the decrease in transparency of the resulting adhesive tape. The SP value of the natural product-based tackifier resin containing an aromatic ring is more preferably 8.0 or more, even more preferably 8.5 or more, particularly preferably 8.6 or more, and more preferably 8.9 or less. Note that even if the tackifier resin is petroleum-based, if the SP value is 9.0 or less, it may be compatible with the aromatic alkenyl polymer block in the radial styrene-based elastomer, but since the general petroleum-based tackifier resin containing an aromatic ring has an SP value of 9.0 or more, it is not compatible with the aromatic alkenyl polymer block and increases the haze, so it is not suitable. Examples of the above-mentioned natural product-based tackifier resin containing an aromatic ring include aromatic modified terpenes, aromatic modified hydrogenated terpenes, terpene phenols, hydrogenated terpene phenols, rosin esters, etc. Among these, aromatic modified terpenes and aromatic modified hydrogenated terpenes are preferred because they are more easily converted into aromatic alkenyl polymer blocks and can suppress a decrease in the transparency of the resulting pressure-sensitive adhesive tape.

[0033] The tackifier resin may be, for example, a natural product-based or petroleum resin-based tackifier resin that does not contain an aromatic ring. The natural product-based or petroleum resin-based tackifier resin that does not contain an aromatic ring has an SP value within the range of 7.5 to 8.5, and is therefore compatible with the conjugated diene polymer block in the radial styrene-based elastomer, and can suppress a decrease in the transparency of the resulting pressure-sensitive adhesive tape. The SP value of the natural product-based or petroleum resin-based tackifier resin that does not contain an aromatic ring is more preferably 7.8 or more, and even more preferably 8.0 or more. Examples of natural product-based or petroleum resin-based tackifier resins not containing an aromatic ring include C5 petroleum resins, alicyclic petroleum resins, terpenes, hydrogenated terpenes, etc. Among these, alicyclic petroleum resins, terpenes, hydrogenated terpenes, and ultra-light-colored rosin esters are preferred because they are more compatible with the conjugated diene polymer block and can suppress a decrease in the transparency of the resulting pressure-sensitive adhesive tape.

[0034] The content of the tackifier resin is not particularly limited, but a preferred lower limit relative to 100 parts by weight of the radial styrene-based elastomer resin is 10 parts by weight, more preferably 20 parts by weight, and a preferred upper limit is 100 parts by weight, more preferably 80 parts by weight. By having the content of the tackifier resin within the above range, a pressure-sensitive adhesive tape having better transparency and high-temperature adhesive strength can be obtained.

[0035] In the present invention, the pressure-sensitive adhesive tape has a thickness of 1 μm at its lower limit and 300 μm at its upper limit. When the thickness of the adhesive tape is within this range, it is possible to suppress the adhesive tape from bleeding out of the release film while exerting sufficient adhesive strength. The preferable lower limit of the thickness of the adhesive tape is 2.5 μm, and the preferable upper limit is 100 μm. The thickness of the adhesive tape can be measured by the following formula using a dial gauge (for example, Mitutoyo Corporation, Digimatic Indicator ID-S1012S) or the like. (Adhesive tape thickness) = (total tape thickness) - (thickness of release film on both sides)

[0036] In the present invention, the release film is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate film and polyethylene naphthalate, polyolefins such as polypropylene and polyethylene, etc. Among these, polyethylene terephthalate is preferred from the viewpoints of cost and strength.

[0037] The method for producing the adhesive tape protected by the release film of the present invention is not particularly limited, and a conventionally known method can be used. For example, the adhesive tape can be produced by coating a solution containing the above-mentioned adhesive and, if necessary, additives such as the above-mentioned tackifier resin and the above-mentioned softener on a film that has been subjected to a release treatment, drying the solution to form an adhesive tape, and then overlaying the film that has been subjected to a release treatment on the adhesive tape.

[0038] The applications of the adhesive tape protected by the release film of the present invention are not particularly limited, but since the adhesive tape has excellent low moisture permeability and low dielectric properties while being less likely to seep out to the outside of the release film during storage, it can be particularly suitably used for fixing electronic device components, fixing in-vehicle components, fixing base station antennas, fixing base station transceivers, and fixing smart glasses. The pressure-sensitive adhesive tape of the present invention used for fixing such electronic device components, vehicle-mounted components, base station antennas, base station transceivers, and smart glasses also constitutes one aspect of the present invention. Examples of the electronic device parts and vehicle-mounted parts include optical parts such as liquid crystal displays. Effect of the Invention

[0039] According to the present invention, it is possible to provide an adhesive tape protected with a release film that can suppress the seepage of the adhesive. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0041] <Base resin> In the examples and comparative examples, radial styrene-based elastomers synthesized by the following methods and commercially available elastomers were used as base resins.

[0042] (Synthesis of radial styrene elastomer) A reaction vessel purged with nitrogen was charged with 500 parts by weight of degassed and dehydrated cyclohexane, 15 parts by weight of styrene, and 5 parts by weight of tetrahydrofuran, and 0.13 parts by weight of n-butyllithium was added at the polymerization initiation temperature of 40°C to carry out temperature-raised polymerization to obtain an aromatic alkenyl polymer block (block A). After the polymerization conversion rate of the aromatic alkenyl polymer block reached approximately 100%, the reaction liquid was cooled to 15°C, and then 85 parts by weight of 1,3-butadiene was added, and temperature-raised polymerization was further carried out to obtain a conjugated diene polymer block (block B). After the polymerization conversion rate reached approximately 100%, 1,3-butadiene was added as a coupling agent, and the polymerization was further carried out at a higher temperature to obtain a conjugated diene polymer block (block B). Tetra 0.06 parts by weight of chlorosilane was added to carry out a coupling reaction. After the coupling reaction was completed, the mixture was left for 10 minutes while hydrogen gas was supplied at a pressure of 0.4 MPa-Gauge.

[0043] Then, 0.03 parts by weight of diethylaluminum chloride and 0.06 parts by weight of bis(cyclopentadienyl)titanium furfuryloxychloride were added to the reaction vessel and stirred. The hydrogenation reaction was started at a hydrogen gas supply pressure of 0.7 MPa-Gauge and a reaction temperature of 80°C. When the absorption of hydrogen was completed, the reaction solution was returned to room temperature and pressure, and the solution was extracted from the reaction vessel to obtain a radial styrene-based elastomer (AB) 4C with n=4.

[0044] (Commercially available elastomer) Septon 2063: SEPS block copolymer, manufactured by Kuraray SIBSTAR 102T: SIBS block copolymer, manufactured by Kaneka Corporation OPPANOL 80: Polyisobutylene, manufactured by BASF <Polymer having crosslinkable functional group> In the examples, the following polymers having crosslinkable functional groups were used. FBP002: Styrene-acrylic acid copolymer, manufactured by Fujikura Chemical Co., Ltd. 8660P:SEBS copolymer, manufactured by JSR

[0045] <Softener> The following softeners were used in the examples and comparative examples. Nisseki Polybutene HV-300 (HV-300 in the table): n-butene-isobutylene copolymer, SP value 7.0-8.5, pour point -55℃ softening point ℃, manufactured by JXTG Nippon Oil & Energy Corporation NOF Polybutene 30N (referred to as 30N in the table): n-butene-isobutylene copolymer, SP value 7.0-8.5, pour point -5°C, manufactured by NOF Corporation NOF Polybutene 200N (referred to as 200N in the table): n-butene-isobutylene copolymer, SP value 7.0-8.5, pour point 15°C, manufactured by NOF Corporation Kuraray LIR290 (LIR290 in the table): Polyisoprene, SP value 7.0-8.5, glass transition point -59℃, softening point ℃, manufactured by Kuraray

[0046] <Tackifier resin> The following tackifying resins were used in the examples and comparative examples. (natural products) YS Resin PX100 (PX100 in the table): Terpene resin, SP value 8.0-8.5, softening point 100°C, manufactured by Yasuhara Chemical Co., Ltd. YS Resin TO105 (referred to as TO105 in the table): Aromatic modified terpene resin, SP value 8.5-9.0, softening point 105°C, manufactured by Yasuhara Chemical Co., Ltd. Rosin Ester KE311 (KE311 in the table): Ultra-light color rosin ester resin, SP value 8.5-9.0, softening point 100°C, manufactured by Arakawa Chemical Industries, Ltd. (Petroleum resin type) Alcon P100: Hydrogenated petroleum resin (alicyclic hydrocarbon resin), SP value 8.0-8.5, softening point 100°C, manufactured by Arakawa Chemical Industries, Ltd. FTR2120: styrene copolymer, SP value 8.7-9.2, softening point 120℃, manufactured by Mitsui Chemicals FMR0150: Styrene copolymer, SP value 8.7-9.2, softening point 145℃, manufactured by Mitsui Chemicals YS Resin SX100 (referred to as SX100 in the table): styrene copolymer, SP value 9.0-9.5, softening point 100°C, manufactured by Yasuhara Chemical Co., Ltd.

[0047] Example 1 (1) Manufacturing of adhesive tapes protected with release films 100 parts by weight of SIBSTAR 102T, 50 parts by weight of LIR290, 20 parts by weight of TO105, and 10 parts by weight of FTR2120 were added to 350 parts by weight of toluene (solvent) to obtain an adhesive solution. A polyethylene terephthalate (PET) film with a release treatment of 50 μm in thickness was prepared as a release film. The obtained adhesive solution was applied to the release-treated surface of the PET film so that the thickness after drying would be 25 μm, and then dried at 100 ° C for 10 minutes to form an adhesive tape. Thereafter, a similar PET film was laminated on the surface of the adhesive tape on which the PET film was not laminated, so that the release-treated surface faced the adhesive tape side, to obtain an adhesive tape protected by a release film. The thickness of the obtained adhesive tape, excluding the release film, was measured using a dial gauge (Mitutoyo Corporation, Digimatic Indicator ID-S1012S). The results are shown in Table 1.

[0048] (2) Measurement of shear storage modulus G' The obtained adhesive tape was laminated to 1000 μm to prepare a measurement sample. The prepared measurement sample was subjected to dynamic viscoelasticity spectrum measurement from -50°C to 200°C under the conditions of 5°C / min and 1Hz in a slow heating shear deformation mode using a viscoelasticity spectrometer (IT Measurement and Control Co., Ltd., DVA-200). From the values ​​of 23°C and 130°C of the obtained dynamic viscoelasticity spectrum, G'(23°C) and G'(130°C) of the adhesive tape were obtained. From the obtained G'(23°C) and G'(130°C), G'(23°C) / G'(130°C) was calculated. The results are shown in Table 1.

[0049] (3) Measurement of moisture permeability The release film was removed from the adhesive tape sample, and four sheets were stacked to prepare a measurement sample with a thickness of 100 μm. The measurement sample was cut into a size of approximately 10 cm x 10 cm, and placed in the measurement section of a water vapor transmission rate measurement device (MOCON, PERMATRAN-W 1 / 50), after which the water vapor transmission rate was measured under conditions of 40°C and 90% RH. Generally, water vapor transmission rate is roughly inversely proportional to the thickness of the adhesive, so the water vapor transmission rate measured at a thickness of 100 μm was doubled to calculate the result at a thickness of 50 μm. The results are shown in Table 1.

[0050] (4) Measurement of dielectric constant The obtained adhesive tape was cut to 55 × 55 mm to obtain a test piece. Next, an aluminum plate (0.1 × 60 × 60 mm), a test piece, and a copper foil (e.g., 0.1 × 55 × 55 mm) were laminated in this order without any air bubbles to prepare a laminate for use as a measurement sample. The dielectric constant of the prepared measurement sample was measured at 10 kHz and 23°C using a measuring device consisting of an LCR meter (Keysight, E4980AL), a capacitance type dielectric constant / dielectric loss tangent measuring system (Keycom, DPT-2141-01), and a thermostatic high temperature and humidity chamber (ESPEC, SH-242). The results are shown in Table 1.

[0051] (Examples 2 to 20, Comparative Examples 1 to 4) An adhesive tape protected with a release film was obtained in the same manner as in Example 1, except that the composition of the adhesive solution and the thickness of the adhesive tape were as shown in Tables 1 and 2, and each measurement was carried out.

[0052] <Evaluation> The adhesive tapes protected with the release films obtained in the Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0053] (Adhesive strength evaluation at 23℃) The adhesive tape protected with a release film was cut to a width of 25 mm to prepare a test piece. Next, the release film on one side of the obtained test piece was peeled off and attached to a glass plate, and the test piece was pressed by rolling a 1 kg rubber roller back and forth once to prepare a measurement sample. After that, the obtained measurement sample was subjected to a 180° peel test at a tensile speed of 300 mm / min according to JIS Z 0237:2009, and the adhesive strength (N / 25 mm) at 23°C was measured.

[0054] (Evaluation of adhesive bleeding) The adhesive tape protected by the release film was cut to 40 mm x 40 mm to obtain a test piece. Next, a 1 kg weight was placed on the center of the obtained test piece and left to stand at 120 ° C for 72 hours. After standing, the width of the adhesive tape protruding from the end of the release film was measured. The bleeding of the adhesive was evaluated as follows: when the maximum protruding width was 0.1 mm or less, it was marked as "◎", when it was more than 0.1 mm and less than 0.2 mm, it was marked as "○", when it was more than 0.2 mm and less than 0.5 mm, it was marked as "△", and when it was more than 0.5 mm, it was marked as "×".

[0055] [Table 1]

[0056] [Table 2] [Industrial Applicability]

[0057] According to the present invention, it is possible to provide an adhesive tape protected with a release film that can suppress the seepage of the adhesive.

Claims

1. The adhesive tape is composed of an adhesive tape and a pair of release films that sandwich the adhesive tape, The adhesive tape contains a rubber-based adhesive, The pressure-sensitive adhesive tape has a shear storage modulus G' (23°C) of 1.0 x 10 ６ Pa or less, and Shear storage modulus G'(130°C) at 130°C is 3.0 x 10 ４ Pa or more, The adhesive tape has a thickness of 1 μm or more and 300 μm or less, The adhesive tape protected with a release film is characterized in that the rubber-based adhesive is a radial styrene-based elastomer having a structure represented by the general formula (A-B)nC. A: Aromatic alkenyl polymer block B: Conjugated diene polymer block C: Component derived from coupling agent n: an integer of 3 or more

2. 2. The adhesive tape protected by a release film according to claim 1, wherein the adhesive tape has a G'(23° C.) / G'(130° C.)<15.

3. The adhesive tape protected by a release film according to claim 1 or 2, characterized in that the adhesive tape contains a softener having an SP value of 8.5 or less and being liquid at 23°C and / or a tackifier resin having an SP value of 8.0 to 9.0 and a softening point of 80°C or higher.

4. The adhesive tape has an SP value of 8.5 or less and contains a softener that is liquid at 23°C; 4. The pressure-sensitive adhesive tape protected by a release film according to claim 1, 2 or 3, wherein the content of the softener is 50 parts by weight or less based on 100 parts by weight of the radial styrene-based elastomer.

5. The pressure-sensitive adhesive tape contains the radial styrene-based elastomer and a polymer having a crosslinkable functional group, The content of the polymer having a crosslinkable functional group is 5 parts by weight or more based on 100 parts by weight of the radial styrene-based elastomer.

5. An adhesive tape protected by the release film according to claim 1.

6. The adhesive tape protected by the release film according to claim 1, 2, 3, 4 or 5, characterized in that it is used for fixing electronic device components, fixing in-vehicle components, fixing base station antennas, fixing base station transceivers, and fixing smart glasses.

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