Adhesive tape protected by 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 by a release film.

Background Art

[0002] In mobile electronic devices such as mobile phones and personal digital assistants (PDAs), adhesive tapes are used to fix components to a housing or the like (for example, Patent Documents 1 and 2). Adhesive tapes are also used for applications such as fixing in-vehicle electronic device components such as in-vehicle panels to a vehicle body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Display devices such as liquid crystal displays are manufactured by laminating a plurality of optical components as materials, and a non-support type transparent adhesive tape (OCA) is used for bonding these optical components. Conventionally, acrylic adhesives have been used in OCA from the viewpoint of transparency. However, since optical components are vulnerable to moisture and static electricity, an adhesive excellent in low moisture permeability and low dielectric properties is required. Therefore, rubber adhesives are being studied as adhesives excellent in low moisture permeability and low dielectric properties.

[0005] On the one hand, the OCA is manufactured with release films laminated on both sides of the adhesive tape. After being punched into a desired shape at the manufacturing site, they are stacked and stored. At this time, if a rubber-based adhesive is used for the adhesive tape, the adhesive that oozes out to the outside of the release film due to the pressure during punching, or the adhesive that gradually oozes out to the outside of the release film due to the weight and self-weight of the stacked adhesive tapes, may enter between the release films of the stacked adhesive tapes and cause contamination.

[0006] An object of the present invention is to provide an adhesive tape protected by a release film capable of suppressing the bleeding of the adhesive.

Means for Solving the Problems

[0007] The present invention is an adhesive tape protected by a release film composed of an adhesive tape and a pair of release films sandwiching the adhesive tape, wherein the adhesive tape has a shear storage modulus G'(23°C) at 23°C of 1.0×10 6 Pa or less, and a shear storage modulus G'(130°C) at 130°C of 3.0×10 4 Pa or more. The adhesive tape has a moisture permeability of 100 g / m when the thickness is 50 μm 2 ·24 hr or less. The adhesive tape has a dielectric constant at 10 kHz of 3 or less. The adhesive tape is an adhesive tape protected by a release film with a thickness of 1 μm or more and 300 μm or less. Hereinafter, the present invention will be described in detail.

[0008] As a result of intensive studies, the inventors have found that the lower the shear storage modulus G' of the adhesive at high temperatures, the greater the fluidity over a long period, that is, the easier it is for the adhesive to ooze out. In the case of an adhesive tape using a conventional rubber-based adhesive, the shear storage modulus G' decreases at high temperatures, so the adhesive easily oozes out to the outside of the release film during storage. Based on this finding, the inventors conducted further studies. As a result, by setting the shear storage modulus at 23°C and the shear storage modulus at 130°C of an adhesive tape having specific moisture permeability and dielectric constant within specific ranges, it was found that an adhesive tape that is difficult to ooze out and has excellent adhesive strength can be obtained while using a rubber-based adhesive, leading to the completion of the present invention.

[0009] The adhesive tape protected by the release film of the present invention comprises an adhesive tape and a pair of release films sandwiching the adhesive tape. By satisfying the shear storage modulus described below, the adhesive tape of the present invention can be made an adhesive tape that is difficult to ooze out to the outside of the release film.

[0010] In the present invention, the shear storage modulus G'(23°C) of the adhesive tape at 23°C is 1.0×10 6 Pa or less. When the shear storage modulus G' of the adhesive tape at 23°C is within the above range, it 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 the above G'(23°C) is 8.0×10 5 Pa, and a more preferable upper limit is 5.0×10 5 Pa. The lower limit of the above G'(23°C) is not particularly limited, but is preferably 1.0×10 4 Pa from the viewpoint of adhesive strength. The above G'(23°C) can be adjusted according to the type of adhesive used for the adhesive tape. Note that the above G'(23°C) can be obtained by the following method. Stack the adhesive tape up to 1000 μm to prepare a measurement sample. For the prepared measurement sample, using a viscoelastic spectrometer (for example, DVA-200 manufactured by IT Measurement & Control Co., Ltd.), the storage modulus at 23 °C can be obtained when measuring the dynamic viscoelastic spectrum from -50 °C to 200 °C under the conditions of a slow temperature rise shear deformation mode of 5 °C / min and 1 Hz.

[0011] In the present invention, the shear storage modulus G'(130 °C) of the above-mentioned adhesive tape is 3.0×10 4 Pa or more. The shear storage modulus at high temperature is correlated with the fluidity over a long period. The lower the shear storage modulus at high temperature, the greater the fluidity over a long period. That is, the adhesive is more likely to ooze out to the outside of the release film. The adhesive tape protected by the release film of the present invention can suppress the oozing out of the adhesive tape to the outside of the release film even when the adhesive tape is stored for a long period by setting the shear storage modulus of the adhesive tape at 130 °C within the above range. The preferable lower limit of the above G'(130 °C) is 5.0×10 4 Pa, and the more preferable lower limit is 1.0×10 5 Pa. The upper limit of the above G'(130 °C) is not particularly limited, but from the viewpoint of handleability, it is preferably 1.0×10 6 Pa. The above G'(130 °C) can be adjusted according to the type of the adhesive used for the adhesive tape. In addition, the above G'(130 °C) can be obtained as the storage modulus at 130 °C when measuring the dynamic viscoelastic spectrum in the same manner as the above G'(23 °C).

[0012] In the adhesive tape protected by the release film of the present invention, the moisture permeability of the above-mentioned adhesive tape when it is 50 μm thick is 100 g / m 2 ·24 hr or less. Since the moisture permeability of the adhesive tape is within the above range when it is 50 μm thick, it can be suitably used for applications where the adhesive tape is used to fix components that are vulnerable to moisture, such as components of electronic devices. The preferable upper limit of the above moisture permeability is 80 g / m 2· 24 hours, more preferably the upper limit is 50 g / m 2 · 24 hours. The lower limit of the above moisture permeability is not particularly limited, and the lower it is, the better. However, the practical limit is about 5 g / m 2 · 24 hours. The above moisture permeability can be adjusted according to the type of adhesive used for the adhesive tape. In addition, the above moisture permeability can be obtained by measuring with a water vapor transmission rate measuring device (for example, PERMATRAN-W 1 / 50 manufactured by MOCON) under the conditions of 40 °C and 90% RH.

[0013] In the adhesive tape protected by the release film of the present invention, the above adhesive tape has a dielectric constant of 3 or less at 10 kHz. When the dielectric constant of the adhesive tape at 10 kHz is within the above range, sufficient insulation can be exhibited to fix the parts of electronic devices that are vulnerable to electricity. The preferable upper limit of the dielectric constant at 10 kHz is 2.8, and the more preferable upper limit is 2.5. The lower limit of the dielectric constant at 10 kHz is not particularly limited, but the practical limit is about 2.0. The above dielectric constant at 10 kHz can be adjusted according to the type of adhesive used for the adhesive tape. In addition, the above dielectric constant at 10 kHz can be measured under the condition of 23 °C using a measuring device composed of an LCR meter (for example, E4980AL manufactured by Keysight), a capacitance-type dielectric constant / dissipation factor measuring system (for example, DPT-2141-01 manufactured by Keycom), and a constant temperature high-temperature and high-humidity machine (for example, SH-242 manufactured by ESPEC).

[0014] It is preferable that the above adhesive tape has G’(23 °C) / G’(130 °C) < 15. The difference between G’(130°C) and G’(23°C) of the above-mentioned pressure-sensitive adhesive tape is small, that is, G’ is less likely to decrease even at high temperatures, so that the seepage of the pressure-sensitive adhesive tape to the outside of the release film can be further suppressed. It is more preferable that G’(23°C) / G’(130°C) of the above-mentioned pressure-sensitive adhesive tape is less than 10, and it is even more preferable that it is less than 8. Note that the lower limit of G’(23°C) / G’(130°C) of the above-mentioned pressure-sensitive adhesive tape is not particularly limited, and the smaller the better, but the limit is about 2 substantially. G’(23°C) / G’(130°C) of the above-mentioned pressure-sensitive adhesive tape can be adjusted according to the type of the adhesive.

[0015] In the present invention, the adhesive constituting the above-mentioned pressure-sensitive adhesive tape is not particularly limited, and examples thereof include rubber-based adhesives, silicone-based adhesives, acrylic-based adhesives, urethane-based adhesives, and the like. Among them, it is preferable that it is a rubber-based adhesive because it satisfies the above-mentioned moisture permeability and the dielectric constant at 10 kHz and is easily available.

[0016] The above-mentioned rubber-based adhesive is preferably a radial styrene-based elastomer. The radial styrene-based elastomer is a branched styrene-based block copolymer having a structure in which a plurality of styrene-based block copolymers (styrene-based elastomers) protrude radially around a coupling agent. The styrene-based block copolymer is composed of a hard segment and a soft segment, and the shear storage modulus G’ at high temperatures can be increased by increasing the content of the hard segment. In addition, since the cross-linked structure in which a plurality of styrene-based block copolymers protrude radially can suppress the relaxation of molecules at high temperatures, the shear storage modulus G’ at high temperatures can be further increased. Furthermore, when the molecular weight of the hard segment of the styrene-based block copolymer is increased, there is a problem that the viscosity becomes too high and the pressure-sensitive adhesive tape cannot be manufactured by the coating method. However, by using a radial styrene-based elastomer, the viscosity can be kept low enough to be manufactured by the coating method even when the molecular weight of the hard segment is increased.

[0017] The above-mentioned radial styrenic elastomer has a structure represented by the general formula (A-B)nC. In the above general formula, A represents an aromatic alkenyl polymer block (hard segment), B represents a conjugated diene polymer block (soft segment), A-B represents a styrenic block copolymer, C represents a component derived from a coupling agent, and n represents an integer of 3 or more. Since it can suppress the bleeding to the outside of the release film of the adhesive tape, n is preferably 4 or more. The upper limit of n is not particularly limited, but from the viewpoint of suppressing the gelation of the above-mentioned radial styrenic elastomer, it is usually 8 or less. The above-mentioned styrenic block copolymer refers to a diblock structure in which one hard segment and one soft segment are bonded.

[0018] The aromatic alkenyl polymer block represented by A above is a repeating unit derived from an aromatic alkenyl compound. Examples of the above-mentioned 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, and the like. Among them, styrene is preferred because it is easily available industrially.

[0019] The conjugated diene polymer block represented by B above is a repeating unit derived from a conjugated diene compound. Examples of the above-mentioned 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, chloroprene, and the like. 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 of their high polymerization reactivity and easy availability industrially.

[0020] Examples of the styrenic block copolymer include styrene-ethylene-propylene-styrene block copolymer (SEPS), hydrogenated styrene-butadiene rubber (HSBR), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene block copolymer (SEP), styrene-ethylene-butylene block copolymer (SEB), styrene-isoprene block copolymer (SI), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene block copolymer (SB), styrene-butadiene-styrene block copolymer (SBS), and the like, as well as combinations thereof. Among them, SEBS is preferred because the shear storage modulus at a higher temperature can be increased.

[0021] It is preferable that the content of the aromatic alkenyl polymer block in the styrenic block copolymer is 50% by weight or less. When the content of the aromatic alkenyl polymer block contained in the styrenic block copolymer is within the above range, a rubber-based pressure-sensitive adhesive excellent in the balance between the shear storage modulus at a high temperature and the adhesive strength at room temperature can be obtained. A more preferable upper limit of the content of the aromatic alkenyl polymer block in the styrenic block copolymer is 35% by weight, and a further preferable upper limit is 20% by weight. The lower limit of the content of the aromatic alkenyl polymer block in the styrenic 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 enhancing optical colorless transparency, the hydrogenation rate of the styrenic block copolymer is preferably 95% or more, and more preferably 96% or more. The hydrogenation rate of the styrenic block copolymer is usually 100% or less.

[0023] The coupling agent serving as a raw material for the component derived from the coupling agent represented by C above is a polyfunctional compound that radially bonds the styrenic block copolymer. Examples of the coupling agent include silane compounds such as halogenated silane and alkoxysilane, tin compounds such as tin halide, epoxy compounds such as polycarboxylic acid ester and epoxidized soybean oil, acrylic esters such as pentaerythritol tetraacrylate, and divinyl compounds such as epoxy silane and divinylbenzene. More specific examples include, for example, trichlorosilane, tribromosilane, tetrachlorosilane, tetrabromosilane, methyltrimethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, tin tetrachloride, diethyl adipate, and the like.

[0024] The molecular weight of the above-mentioned radial styrene-based elastomer is not particularly limited, but the preferable lower limit is 50,000, and the more preferable lower limit is 100,000. When the molecular weight of the radial styrene-based elastomer is within the above range, the adhesive strength and handleability of the obtained pressure-sensitive adhesive tape can be further improved. The upper limit of the above molecular weight is not particularly limited, and the larger the molecular weight, the more the bleeding of the adhesive can be suppressed. However, since the viscosity increases as the molecular weight increases, the limit for practical production is about 700,000.

[0025] The above-mentioned pressure-sensitive adhesive tape preferably contains the above-mentioned radial styrene-based elastomer and a polymer having a crosslinkable functional group. By blending a polymer having a crosslinkable functional group with the 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 the bleeding to the outside of the release film of the pressure-sensitive adhesive tape can be further suppressed. In addition, by blending a polymer having a crosslinkable functional group, the elongation during processing of the radial styrene-based elastomer can also be suppressed, so that the deformation due to the pressure during punching of the pressure-sensitive adhesive tape can be suppressed.

[0026] The polymer having the 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 copolymers, etc. Among them, amine-modified SEBS is preferable from the viewpoint of compatibility with the base resin.

[0027] The content of the polymer having the crosslinkable functional group is preferably 5 parts by weight or more with respect to 100 parts by weight of the above-mentioned radial styrene-based elastomer. When the content of the polymer having the crosslinkable functional group is within the above range, the radial styrene-based elastomer can be sufficiently crosslinked, and bleeding to the outside 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 the crosslinkable functional group is 8 parts by weight, and a further preferable lower limit is 10 parts by weight. The upper limit of the content of the polymer having the crosslinkable functional group is not particularly limited, but is preferably 50 parts by weight from the viewpoint of compatibility with the base resin and suppressing a decrease in adhesiveness due to an increase in the gel fraction and hardening of the paste.

[0028] In the present invention, the above-mentioned adhesive tape has an SP value of 8.5 or less and may contain a liquid softening agent at 23°C. By blending the above softening agent, the adhesive strength and water vapor barrier property of the resulting pressure-sensitive adhesive tape at room temperature can be further improved. In addition, since radial styrene-based elastomers are hardly compatible with additives usually used in pressure-sensitive adhesive tapes, there is a problem that the transparency decreases. However, since the above softening agent has the above SP value, it is easily compatible with the conjugated diene polymer block in the styrene-based block copolymer. Therefore, even when a radial styrene-based elastomer is used as the rubber-based pressure-sensitive adhesive, a decrease in the transparency of the resulting pressure-sensitive adhesive tape can be suppressed. Examples of the above softening agent include polybutene, polyisoprene, paraffinic oil, etc. Among them, polybutene is preferable because there is little bleed to the surface of the adherend over time. Note that while the above softening agent improves the adhesive strength and water vapor barrier property at room temperature, if used in too large an amount, the shear storage modulus at high temperature may be decreased. Therefore, when more importance is attached to suppressing the bleeding of the pressure-sensitive adhesive rather than the adhesive strength and water vapor barrier property at room temperature, it is preferable to use the minimum amount possible. In this specification, the SP value is called the solubility parameter and is an index that can represent the ease of dissolution. In this specification, the Fedors method (R.F. Fedors, Polym. Eng. Sci., 14(2), 147-154(1974)) is used to calculate the SP value.

[0029] Examples of the softening agent that satisfies the above SP value include polybutene, polyisoprene, paraffinic oil, etc. Among them, polybutene is preferable because it is well compatible with the above radial styrene-based elastomer and can further suppress a decrease in transparency.

[0030] The content of the above softening agent is not particularly limited, but the preferable upper limit with respect to 100 parts by weight of the above radial styrene-based elastomer is 100 parts by weight, and the more preferable upper limit is 50 parts by weight. As described above, the higher the content of the above softening agent, the better the adhesive force and the water vapor barrier property at room temperature, but the bleeding suppression property decreases. Therefore, when the content of the above softening agent is within the above range, an adhesive tape with a better balance between the adhesive force and the water vapor barrier property and the bleeding suppression property at room temperature can be obtained.

[0031] In the present invention, it is preferable that the above adhesive tape 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 into the adhesive tape, the adhesive force at high temperature can be further improved. Further, since the SP value of the tackifier resin is within the above range, the tackifier resin is compatible with the above radial styrene-based elastomer, so that a decrease in the transparency of the obtained adhesive tape can be suppressed. The upper limit of the softening point of the above tackifier resin is not particularly limited, but considering the temperature used, it is preferably 140°C. In addition, the above softening point can be measured according to JIS K2207.

[0032] Examples of the tackifier resin include natural tackifier resins containing an aromatic ring. Among the tackifier resins containing an aromatic ring, natural tackifier resins have an SP value of 9.0 or less, and thus are compatible with the aromatic alkenyl 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 tackifier resin containing an aromatic ring is more preferably 8.0 or more, still more preferably 8.5 or more, particularly preferably 8.6 or more, and more preferably 8.9 or less. Note that if the SP value is 9.0 or less, even a petroleum-based tackifier resin may be compatible with the aromatic alkenyl polymer block in the radial styrene-based elastomer. However, since a 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 is not suitable because the haze increases. Examples of the natural tackifier resin containing an aromatic ring include aromatic-modified terpene, aromatic-modified hydrogenated terpene, terpene phenol, hydrogenated terpene phenol, rosin ester, and the like. Among them, aromatic-modified terpene and aromatic-modified hydrogenated terpene are preferable because they are more likely to form an aromatic alkenyl polymer block and can suppress a decrease in the transparency of the resulting pressure-sensitive adhesive tape.

[0033] Examples of the tackifier resin also include natural or petroleum resin-based tackifier resins that do not contain an aromatic ring. Since the natural or petroleum resin-based tackifier resin that does not contain an aromatic ring has an SP value in the range of 7.5 to 8.5, it is 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 or petroleum resin-based tackifier resin that does not contain an aromatic ring is more preferably 7.8 or more, and still more preferably 8.0 or more. Examples of the tackifying resin that does not contain an aromatic ring and is a natural product-based or petroleum resin-based include C5 petroleum resin, alicyclic petroleum resin, terpene, hydrogenated terpene, etc. Among them, alicyclic petroleum resin, terpene, hydrogenated terpene, and ultra-light-colored rosin ester are preferred because they are more easily compatible with the conjugated diene polymer block and can suppress the decrease in transparency of the resulting pressure-sensitive adhesive tape.

[0034] The content of the above-mentioned tackifying resin is not particularly limited, but the preferable lower limit with respect to 100 parts by weight of the above-mentioned radial styrene-based elastomer resin is 10 parts by weight, the more preferable lower limit is 20 parts by weight, the preferable upper limit is 100 parts by weight, and the more preferable upper limit is 80 parts by weight. When the content of the above-mentioned tackifying resin is within the above range, a pressure-sensitive adhesive tape having better transparency and high-temperature adhesiveness can be obtained.

[0035] In the present invention, the above-mentioned pressure-sensitive adhesive tape has a lower limit of thickness of 1 μm and an upper limit of 300 μm. When the thickness of the above-mentioned pressure-sensitive adhesive tape is within this range, bleeding to the outside of the release film of the pressure-sensitive adhesive tape can be suppressed while exhibiting sufficient adhesiveness. The preferable lower limit of the thickness of the above-mentioned pressure-sensitive adhesive tape is 2.5 μm, and the preferable upper limit is 100 μm. The thickness of the above-mentioned pressure-sensitive adhesive tape can be measured by the following formula using a dial gauge (for example, Mitutoyo Corporation, Digital Indicator ID-S1012S). (Pressure-sensitive adhesive tape thickness) = (Total tape thickness) - (Thickness of both-sided release film)

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

[0037] The method for manufacturing the pressure-sensitive 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, a solution in which the above-mentioned pressure-sensitive adhesive and additives such as the above-mentioned tackifier resin and the above-mentioned softening agent are blended as necessary is applied and dried on a film subjected to a release treatment to form a pressure-sensitive adhesive tape, and a film subjected to a release treatment is laminated on the pressure-sensitive adhesive tape. It can be manufactured by overlaying.

[0038] The use of the pressure-sensitive adhesive tape protected by the release film of the present invention is not particularly limited, but it has excellent low moisture permeability and low dielectric properties, and the pressure-sensitive adhesive tape is difficult to ooze out to the outside of the release film during storage. Therefore, it can be particularly preferably used for fixing electronic device parts, fixing in-vehicle parts, fixing base station antennas, fixing base station transceivers, and fixing smart glasses. The pressure-sensitive adhesive tape of the present invention used for such uses as fixing electronic device parts, fixing in-vehicle parts, fixing base station antennas, fixing base station transceivers, and fixing smart glasses is also one of the present inventions. Examples of the above-mentioned electronic device parts and in-vehicle parts include optical parts such as liquid crystal displays.

Effects of the Invention

[0039] According to the present invention, it is possible to provide a pressure-sensitive adhesive tape protected by a release film that can suppress the bleeding of the pressure-sensitive adhesive.

Modes for Carrying Out the Invention

[0040] Examples will be given below to explain the aspects of the present invention in more detail, but the present invention is not limited to these examples only.

[0041] <Base Resin> In Examples and Comparative Examples, a radial styrene-based elastomer synthesized by the following method and a commercially available elastomer were used as base resins.

[0042] (Synthesis of Radial Styrene-Based Elastomer) Into a nitrogen-substituted reaction vessel, 500 parts by weight of degassed and dehydrated cyclohexane, 15 parts by weight of styrene, and 5 parts by weight of tetrahydrofuran were charged. 0.13 parts by weight of n-butyllithium was added at a polymerization start temperature of 40 °C, and temperature-rising polymerization was carried out to obtain an aromatic alkenyl polymer block (block A). After the polymerization conversion rate of the aromatic alkenyl polymer block reached about 100%, the reaction solution was cooled to 15 °C, then 85 parts by weight of 1,3-butadiene was added, and further temperature-rising polymerization was carried out to obtain a conjugated diene polymer block (block B). After the polymerization conversion rate reached almost 100%, 0.06 parts by weight of tetrachlorosilane was added as a coupling agent, and a coupling reaction was carried out. After the coupling reaction was completed, the reaction solution was left for 10 minutes while supplying hydrogen gas at a pressure of 0.4 MPa-Gauge.

[0043] Thereafter, 0.03 parts by weight of diethylaluminum chloride and 0.06 parts by weight of bis(cyclopentadienyl)titanium furfuryloxy chloride 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 normal temperature and normal pressure and withdrawn from the reaction vessel to obtain a radial styrene-based elastomer (A-B) with n = 4 4 C.

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

[0045] <Softening agent> In the examples and comparative examples, the following softening agents were used. · Nisseki Polybutene HV-300 (HV-300 in the table): n-butene-isobutylene copolymer, SP value 7.0 - 8.5, pour point -55°C, softening point [unit not specified], manufactured by JXTG Energy Corporation · NOF Polybutene 30N (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 (200N in the table): n-butene-isobutylene copolymer, SP value 7.0 - 8.5, pour point 15°C, manufactured by NOF Corporation · Kuraprene LIR290 (LIR290 in the table): polyisoprene, SP value 7.0 - 8.5, glass transition point -59°C, softening point [unit not specified], manufactured by Kuraray Co., Ltd.

[0046] <Adhesion - promoting resin> The following adhesion - promoting resins were used in the examples and comparative examples. (Natural product - based) · 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 (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 - colored rosin ester resin, SP value 8.5 - 9.0, softening point 100°C, manufactured by Arakawa Chemical Industries, Ltd. (Petroleum resin - based) · 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°C, manufactured by Mitsui Chemicals, Inc. · FMR0150: styrene copolymer, SP value 8.7 - 9.2, softening point 145°C, manufactured by Mitsui Chemicals, Inc. · YS Resin SX100 (SX100 in the table): styrene copolymer - based, SP value 9.0 - 9.5, softening point 100°C, manufactured by Yasuhara Chemical Co., Ltd.

[0047] (Example 1) (1) Manufacture of an adhesive tape protected by a release film 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 (solvent) toluene to obtain an adhesive solution. A polyethylene terephthalate (PET) film with a thickness of 50 μm and subjected to a release treatment was prepared as a release film. The obtained adhesive solution was coated on the release-treated surface of the PET film so that the thickness after drying was 25 μm, and then dried at 100 °C for 10 minutes to form an adhesive tape. Then, a similar PET film was laminated on the surface of the adhesive tape where the PET film was not laminated, with the release-treated surface facing the adhesive tape side, to obtain an adhesive tape protected by a release film. For the obtained adhesive tape, the thickness of the 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 tapes were laminated up to 1000 μm to prepare measurement samples. For the prepared measurement samples, a dynamic viscoelastic spectrum from -50 °C to 200 °C was measured using a viscoelastic spectrometer (IT Measurement & Control Co., Ltd., DVA-200) under the conditions of a slow heating rate of 5 °C / min and 1 Hz in a shear deformation mode. From the values at 23 °C and 130 °C of the obtained dynamic viscoelastic 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 water vapor permeability The release film of the adhesive tape sample was peeled off, and four layers were stacked to prepare a measurement sample with a thickness of 100 μm. The prepared measurement sample was cut into a size of about 10 cm × 10 cm and installed in the measurement part of a water vapor transmission rate measuring device (MOCON, PERMATRAN-W 1 / 50), and then the water vapor transmission rate was measured under the conditions of 40 °C and 90% RH. Generally, since the water vapor transmission rate is approximately inversely proportional to the thickness of the adhesive, the result at a thickness of 50 μm was calculated by doubling the measured result of the water vapor transmission rate at a thickness of 100 μm obtained. The results are shown in Table 1.

[0050] (4) Measurement of dielectric constant The obtained adhesive tape was cut into 55×55 mm to obtain test pieces. Next, a laminate was prepared by laminating an aluminum plate (0.1×60×60 mm), a test piece, and a copper foil (e.g., 0.1×55×55 mm) in this order without air bubbles, and used as a measurement sample. The prepared measurement sample was measured for the dielectric constant under the conditions of 10 kHz and 23 °C using a measuring device composed of an LCR meter (manufactured by Keysight Technologies, E4980AL), a capacitance method non-dielectric constant / dissipation factor measurement system (manufactured by Keycom, DPT-2141-01), and a constant temperature high-temperature and high-humidity machine (manufactured by ESPEC, SH-242). The results are shown in Table 1.

[0051] (Examples 2 to 20, Comparative Examples 1 to 4) An adhesive tape protected by a release film was obtained and each measurement was carried out 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.

[0052] (Evaluation) The following evaluations were performed on the adhesive tapes protected by the release films obtained in the examples and comparative examples. The results are shown in Tables 1 and 2.

[0053] (Evaluation of adhesive strength at 23 °C) The adhesive tape protected by the release film was cut into 25 mm widths to prepare test pieces. 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 pressure-bonded by reciprocating once with a 1 kg rubber roller on the test piece to prepare a measurement sample. Then, for the obtained measurement sample, a 180° peel test was performed according to JIS Z 0237:2009 under the condition of a tensile speed of 300 mm / min, and the adhesive strength (N / 25 mm) at 23 °C was measured.

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

[0055]

Table 1

[0056]

Table 2

Industrial Applicability

[0057] According to the present invention, it is possible to provide a pressure-sensitive adhesive tape protected by a release film that can suppress the bleeding 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 has a shear storage modulus G' (23°C) of 1.0 x 10 ６ Pa or less, and Shear storage modulus G'(130°C) is 3.0 x 10 ４ Pa or more, The adhesive tape has a moisture permeability of 100 g / m when it is 50 μm thick. ２ - 24 hours or less, The pressure-sensitive adhesive tape has a dielectric constant of 3 or less at 10 kHz, The adhesive tape has a thickness of 1 μm or more and 300 μm or less.

1. An adhesive tape protected with a release film.

2. 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.

1. An adhesive tape protected with a release film.

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

4. 4. The adhesive tape protected by a release film according to claim 2 or 3, 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

5. The adhesive tape protected by a release film according to claim 1, 2, 3 or 4, 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.

6. 3. The pressure-sensitive adhesive tape protected by a release film according to claim 1, 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.

7. 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.

7. An adhesive tape protected by the release film according to claim 4, 5 or 6.

8. The adhesive tape protected by the release film according to claim 1, 2, 3, 4, 5, 6 or 7, 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.

Images