Flame Retardant Adhesive Tape

Abstract

To provide a fire-resistant adhesive tape capable of keeping an oxygen index of 26 or higher and showing an objective index of fire resistance.SOLUTION: A fire-resistant adhesive tape of the invention includes a substrate sheet 3 formed by laminating a film 2 on one surface or both surfaces of a cloth body 1 composed of striated bodies 11. A fire-resistant layer 4 and an adhesive layer 5 are laminated in that order on at least one surface of the substrate sheet 3. The fire-resistant layer 4 has a storage elastic modulus of 2.0×105 Pa or higher at 23°C. The adhesive layer 5 has a storage elastic modulus of 5.0×104 Pa or higher at 23°C and an oxygen index of 26 or higher.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flame-retardant pressure-sensitive adhesive tape, and more particularly to a flame-retardant pressure-sensitive adhesive tape that can always maintain an oxygen index of 26 or more and provide an objective indicator of flame retardancy. [Background technology]

[0002] Patent Document 1 discloses a non-halogen flame-retardant tape for bundling electric wires, which has layers in the following order on one side of an artificial silk woven fabric: a PE layer, a flame-retardant layer made of an acrylic resin binder, and an adhesive layer, and which exhibits flexibility, ease of tearing by hand, and the ability to prevent abnormal noise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-224822 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, by providing a flame-retardant layer / adhesive layer in that order, the flame-retardant layer is not the outermost layer, which prevents the adherend from being soiled when the flame-retardant adhesive tape attached to the adherend is peeled off. However, the oxygen index is insufficient, meaning that the flame retardant effect based on the flame retardant cannot be exerted, and therefore a flame-retardant adhesive tape that can ensure an oxygen index of 26 or higher is required.

[0005] An object of the present invention is to provide a flame-retardant pressure-sensitive adhesive tape that can consistently maintain an oxygen index of 26 or more and provide an objective indicator of flame retardancy.

[0006] Other objects of the present invention will become apparent from the following description. [Means for solving the problem]

[0007] The above-mentioned problem is solved by providing a base sheet having a film laminated on one or both sides of a cloth-like body made of a filament, a flame-retardant layer and a pressure-sensitive adhesive layer being provided in this order on at least one side of the base sheet, the thickness of said flame retardant layer is 2 to 150 μm, the amount of flame retardant in said flame retardant layer (based on solid content) is 15 to 70% by weight, said pressure-sensitive adhesive layer is substantially free of a flame retardant, and the combined thickness of said flame retardant layer and said pressure-sensitive adhesive layer is 3 to 200 μm, The storage modulus of the flame-retardant layer at 23° C. is 2.0×10 5 The pressure-sensitive adhesive layer has a storage modulus of 5.0×10 Pa or more at 23° C. 4 The problems are solved by a flame-retardant adhesive tape having a flame retardant viscosity of 10 Pa or more and an oxygen index of 26 or more. Effect of the Invention

[0008] According to the present invention, it is possible to provide a flame-retardant pressure-sensitive adhesive tape which can always maintain an oxygen index of 26 or more and provide an objective index of flame retardancy. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a vertical cross-sectional view illustrating a flame-retardant adhesive tape according to an embodiment of the present invention. [Diagram 2] A longitudinal cross-sectional view illustrating an example of a flat yarn DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the embodiments of the present invention will be described in detail.

[0011] FIG. 1 is a vertical cross-sectional view illustrating a flame-retardant pressure-sensitive adhesive tape according to one embodiment of the present invention. The flame-retardant adhesive tape shown in Figure 1 has a base sheet 3 formed by laminating a film 2 on both sides of a cloth-like body 1 consisting of a filament 11, a flame-retardant layer 4 provided on one side of the base sheet 3, and an adhesive layer 5 provided on the underside (top of the drawing) of the flame-retardant layer 4.

[0012] The flame-retardant layer 4 is a layer formed by blending a flame retardant with a binder resin, and the pressure-sensitive adhesive layer 5 is a layer containing a pressure-sensitive adhesive. This pressure-sensitive adhesive layer 5 does not substantially contain a flame retardant.

[0013] Here, the pressure-sensitive adhesive layer 5 being substantially free of flame retardant means that the pressure-sensitive adhesive layer 5 does not contain any flame retardant or contains a small amount of flame retardant within a range that does not impair the object of the present invention. By not containing substantially any flame retardant in the pressure-sensitive adhesive layer 5, contamination of the adherend by the flame retardant can be reliably prevented.

[0014] Even if a small amount of flame retardant is blended in the pressure-sensitive adhesive layer 5, the blending amount (on a solid content basis) is less than 0.1% by weight relative to the total weight of the flame-retardant layer. This amount can suitably prevent contamination of the adherend caused by the pressure-sensitive adhesive layer 5.

[0015] The adhesive used in the adhesive layer 5 is not particularly limited, but it is preferable to use at least one type selected from acrylic adhesives.

[0016] As the acrylic adhesive, an acrylic polymer obtained by polymerizing a carboxyl group-containing monomer and a (meth)acrylic acid alkyl ester monomer can be used.

[0017] The alkyl group desirably has about 1 to 12 carbon atoms. Specific examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isononyl (meth)acrylate. Of these, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.

[0018] Examples of the carboxyl group-containing monomer include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid; dicarboxylic acids such as fumaric acid and maleic acid; and monoesters of these. Of these carboxyl group-containing radical polymerizable monomers, acrylic acid and methacrylic acid are preferably used. The amount of the carboxyl group-containing polymerizable monomer is preferably about 1 to 20% by weight of the total monomers.

[0019] The acrylic adhesive may be copolymerized with a small amount of a modifying component monomer for the purpose of adjusting the glass transition temperature, polarity, etc. Examples of such monomers include methyl (meth)acrylate, ethyl (meth)acrylate, acrylamide, vinyl acetate, styrene, acrylonitrile, vinylpyrrolidone, etc.

[0020] The acrylic polymer may contain a polyfunctional compound having two or more functional groups reactive with a carboxyl group in the molecule, or a polyfunctional compound and a monofunctional compound having one of the functional groups in the molecule. Examples of this type of functional group-containing compound include an isocyanate group-containing compound, an epoxy group (or a glycidyl group)-containing compound, an aziridinyl group-containing compound, a metal complex, and a melamine-based compound.

[0021] Although there are no particular limitations on the solution viscosity and solid content of the acrylic pressure-sensitive adhesive in the present invention, the solution viscosity is preferably 5000 to 15000 mPa s, more preferably 8000 to 10000 mPa s, and the solid content is preferably 30 to 70%, more preferably 40 to 60%. The solution viscosity is measured using a Type H Brookfield viscometer at 25°C with a No. 4 rotor at 10 rpm for 60 seconds, after which the pointer reading is read and the solution viscosity is calculated using the following formula: Viscosity [mPa s] = Pointer reading x 200

[0022] The thickness of the pressure-sensitive adhesive layer 5 is not particularly limited, but is preferably 1 to 50 μm.

[0023] Next, the binder resin used in the flame-retardant layer 4 is not particularly limited, but an acrylic resin or a polyester resin is preferably used. Furthermore, by using a binder resin for the flame-retardant layer 4 that is the same as or similar to the adhesive used for the adhesive layer 5, interlayer peeling between the flame-retardant layer 4 and the adhesive layer 5 can also be suitably prevented. In this specification, the acrylic resin or polyester resin that is the binder resin is referred to as an acrylic adhesive or a polyester adhesive, as necessary.

[0024] As the acrylic resin, the compounds exemplified for the pressure-sensitive adhesive layer 5 can be used.

[0025] The polyester-based resin may be one constituted by a polyester obtained by polycondensation of a di- or higher functional carboxylic acid component and a diol component. Examples of the carboxylic acid component include sebacic acid, dimer acids derived from oleic acid, erucic acid, etc., adipic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dodecenylsuccinic anhydride, fumaric acid, succinic acid, dodecanedioic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic acid, maleic anhydride, itaconic acid, citraconic acid, and other aliphatic or alicyclic dicarboxylic acids, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid. The diol component includes an aliphatic diol, a polyether glycol, and the like.

[0026] Although there are no particular limitations on the solution viscosity and solid content of the polyester-based pressure-sensitive adhesive of the present invention, the solution viscosity is preferably 4000 to 13000 mPa s, more preferably 8000 to 10000 mPa s, and the solid content is preferably 30 to 70%, more preferably 40 to 60%. The solution viscosity was measured using a B-type viscometer, H type, at 25°C and a rotor. After rotating for 60 seconds at 10 rpm in No. 4, read the pointer reading and calculate using the following formula. do. Viscosity [mPa s] = Pointer reading x 200

[0027] In the flame-retardant layer 4, the flame retardant to be blended together with the binder resin is not particularly limited, and for example, a compound selected from a halogen-based flame retardant and a non-halogen-based flame retardant can be suitably used.

[0028] The halogen-based flame retardant is not particularly limited as long as it is a flame retardant containing a halogen element in the molecule, and examples thereof include bromine-based flame retardants.

[0029] The non-halogen flame retardant is not particularly limited as long as it is a flame retardant that does not contain a halogen element in the molecule, and examples thereof include phosphorus-based flame retardants, melamine-based flame retardants, etc. Examples of melamine-based flame retardants include melamine cyanurate, etc.

[0030] The amount of the flame retardant in the flame-retardant layer 4 (based on solids content) is preferably 15 to 70% by weight, and more preferably 20 to 60% by weight, based on the total weight of the flame-retardant layer.

[0031] The thickness of the flame-retardant layer 4 is preferably from 2 to 150 μm, and more preferably from 10 to 100 μm.

[0032] The thickness of the combined pressure-sensitive adhesive layer 5 and flame-retardant layer 4 is preferably 3 to 200 μm, and more preferably 15 to 150 μm.

[0033] As a specific method for forming the flame-retardant layer 4 and the pressure-sensitive adhesive layer 5, the flame-retardant layer 4 can be first formed on the base sheet 3, and then the pressure-sensitive adhesive layer 5 can be formed on the flame-retardant layer 4.

[0034] In this case, the method for forming each layer can be selected from direct coating and transfer, and the formation methods may be the same or different for the flame-retardant layer 4 and the pressure-sensitive adhesive layer 5. Alternatively, the pressure-sensitive adhesive layer 5 and the flame-retardant layer 4 may be formed in this order on a transfer process paper, and then transferred onto the base sheet 3 all at once.

[0035] In the present invention, the oxygen index of the flame-retardant pressure-sensitive adhesive tape is 26 or more, and the storage modulus of the flame-retardant layer 4 at 23° C. is 1.0×105 The storage modulus of the pressure-sensitive adhesive layer 5 at 23° C. is 5.0×10 Pa or more. 4 Pa or more.

[0036] The storage modulus was measured as follows. The test pieces used were a test piece of the flame-retardant layer and a test piece of the pressure-sensitive adhesive layer. Test piece: The flame-retardant layer was formed into a strip of 4 mm x 25 mm to serve as a test piece, while the pressure-sensitive adhesive layer was formed into a circular shape of 20 mm in diameter to serve as a test piece.

[0037] Measurement device 1: Measurement of adhesive layer test piece Equipment: "HAAKE MARS": Thermo Fisher Scientific Temperature...-50℃~200℃ Heating rate...3℃ / min Frequency: 1Hz Distortion: 0.1% Fixture: φ20 mm parallel plate Under the above measurement conditions, the storage modulus at 23°C was obtained.

[0038] Measurement device 2: Measurement of flame-retardant layer test pieces Equipment: "DVA-200" manufactured by IT Measurement and Control Co., Ltd. (tensile method) Temperature...-50℃~200℃ Heating temperature...3℃ / min Frequency: 1Hz Under the above measurement conditions, the storage modulus at 23°C was obtained.

[0039] It is preferable that layer 4 and / or layer 5 contain a crosslinking agent as a curing agent. As the crosslinking agent, for example, an isocyanate-based crosslinking agent is preferably used. In addition, the crosslinking agent is not limited to the above, and examples thereof include metal chelate-based compounds, epoxy-based compounds, metal salt compounds, metal alkoxide compounds, and aldehyde-based compounds.

[0040] The crosslinking agent to be added to the layers 4 and 5 is preferably contained in an amount of 0.01 to 15 parts by weight relative to 100 parts by weight of the resin component of the layers 4 and 5.

[0041] Although an example in which a crosslinking agent is blended in the layers 4 and 5 has been described, the present invention is not particularly limited thereto, and examples thereof include a method of photocuring the layers 4 and 5 using a photocuring means, a method of curing the layers 4 and 5 by irradiating an ultraviolet-curable resin with ultraviolet rays, and a method of thermally curing a thermosetting resin to cure the layers 4 and 5. In the case of these methods, it is sufficient to cure at least one of the layers 4 and 5.

[0042] This embodiment includes (1) an embodiment in which a crosslinking agent is blended into the flame-retardant layer 4 to harden the flame-retardant layer 4, (2) an embodiment in which a crosslinking agent is blended into the adhesive layer 5 to harden the adhesive layer 5, and (3) an embodiment in which a crosslinking agent is blended into both the flame-retardant layer 4 and the adhesive layer 5 to harden both the flame-retardant layer 4 and the adhesive layer 5.

[0043] Next, the fabric-like body 1 constituting the base sheet 3 will be described in detail. There are no particular limitations on the material of the filaments 11 constituting the fabric-like body 1, and for example, polymeric materials and the like can be preferably used, with thermoplastic resins being particularly suitable. Examples of such thermoplastic resins that can be used include high-density polyethylene, linear low-density polyethylene, propylene polymers, ethylene-propylene block copolymers and other olefin polymers, polyethylene terephthalate, polybutylene terephthalate and other polyesters, nylon 6, nylon 66 and other polyamides, polyacrylic resins, vinylidene chloride resins, and the like.

[0044] The shape of the filament 11 may be any shape selected from monofilament, tape, yarn, split yarn, multifilament, staple fiber, etc., among which a tape-like flat yarn is preferable. Such a flat yarn can also be made into a split yarn by making a large number of small cuts in the longitudinal direction (vertical direction).

[0045] The filament 11 may be unstretched, but is preferably stretched. The stretching may be either uniaxial or biaxial.

[0046] The cloth-like body 1 can be a woven or knitted fabric made of filaments 11. The cloth-like body 1 can also be a cross-bonded fabric formed by aligning filaments 11 along two or more axes, overlapping them, and heat-sealing the intersections between the filaments. The filaments 11 can be aligned, for example, along two axes (vertical and horizontal), three axes (vertical and both diagonals), or four axes (vertical, horizontal, and both diagonals). When the fabric-like body 1 is composed of filaments 11 made of flat yarn, the filaments 11 made of flat yarn are preferably woven in a flat state. Being a woven fabric made of flat yarn provides excellent hand-tearability.

[0047] Preferred embodiments of the cross-sectional shape of the filament 11 made of flat yarn are exemplarily shown in Figs. 2(a) to 2(g). Figure 2(a) is an example in which the flat yarn is configured as a single layer, Figure 2(b) is an example in which a bonding layer 13 is laminated on one side of a base layer 12, and Figure 2(c) is an example in which a bonding layer 13 is laminated on both sides of a base layer 12. 2(d) and 2(e) show examples of a core-sheath structure in which the base layer 12 is a core material and the bonding layer 13 is a sheath. FIG. 2(f) shows an example of a side-by-side structure in which bonding layers 13 are provided on both sides of a base layer 12 in the width direction. FIG. 2(g) shows an example of an island-in-sea structure in which the base layer 12 is an island and the bonding layer 13 is a sea.

[0048] The bonding layer 13 is preferably made of a thermoplastic resin having a lower melting point and excellent heat fusion property than the thermoplastic resin constituting the base layer 12. The bonding layer 13 can be made of a thermoplastic resin having a melting point 10° C. or more, preferably 15° C. or more lower than the thermoplastic resin constituting the base layer 12. When utilizing the difference in melting points described above to join filaments together or to join a cloth-like body and a film, heat is applied at a temperature between the melting points of bonding layer 13 and base layer 12 to perform heat fusion. This causes bonding layer 13 to melt and base layer 12 to remain unmelted, so that after filaments 11 have been made into a cloth-like body, filaments 11 can be suitably joined together or the cloth-like body 1 and film 2 can be suitably joined together.

[0049] The yarn density of the woven fabric-like body 1 is not particularly limited, but the warp yarns are preferably 10 to 80 yarns / 25.4 mm, and more preferably 20 to 60 yarns / 25.4 mm, and the weft yarns are preferably 5 to 40 yarns / 25.4 mm, and more preferably 10 to 30 yarns / 25.4 mm. Furthermore, it is preferable that the fineness of the warp yarns is lower than that of the weft yarns, and the number of warp yarns per weft is greater than the number of weft yarns per weft.

[0050] Next, film 2 will be described. The film 2 is preferably made of a thermoplastic resin. Examples of the thermoplastic resin include ethylene-α-olefin copolymers such as high-pressure low-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymers, and other olefin-based polymers, ethylene-vinyl acetate copolymers, polypropylene, and other ethylene-(meth)acrylic monomer copolymers, such as ethylene-methyl acrylate copolymers, ethylene-methyl methacrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-ethyl methacrylate copolymers, and ethylene-n-butyl acrylate copolymers, polyesters, such as polyethylene terephthalate and polybutylene terephthalate, polyamides, such as nylon 6 and nylon 66, polyvinyl chloride, and polyurethane. Among these, olefin-based polymers are preferred.

[0051] The density of olefin polymers is 0.870 to 0.942 g / cm 3 and preferably 0.875 to 0.936 g / cm 3 The flexural rigidity of the olefin polymer is preferably 10 to 200 MPa.

[0052] The thickness of the film 2 is not particularly limited, but is preferably 10 to 80 μm.

[0053] In the base sheet 3 of the present invention, the film 2 is laminated on one or both sides of the cloth-like body 1, but the method for laminating the cloth-like body 1 and the film 2 is not particularly limited, and for example, a lamination method can be used. Examples of the lamination method include a method in which the film 2 is formed in advance and laminated using an adhesive, a method in which the film is laminated using a dry lamination method or a thermal lamination method, a method in which a synthetic resin that will become the film 2 is coated on the surface of the cloth-like body 1, and a method in which the film 2 is extrusion laminated onto a cloth-like body 1 that has been formed in advance.

[0054] In the base sheet 3, it is also preferable that a part of the resin constituting the film 2 is impregnated into the gaps between the filaments 11 constituting the cloth-like body 1.

[0055] The flame-retardant pressure-sensitive adhesive tape of the present invention has excellent flame retardancy with an oxygen index of at least 26. The oxygen index is measured by the following method. In accordance with JIS K7201-2, a test piece made of flame-retardant adhesive tape was supported vertically in a combustion column to which a mixture of oxygen and nitrogen gas was supplied, and the oxygen concentration in the mixed gas was changed to measure the minimum oxygen concentration (volume %) at which the test piece could continue to burn, which was taken as the oxygen index (the unit (volume %) is omitted in the oxygen index). The criteria for continued burning are "burning for 3 minutes or more" or "burning distance of 50 mm or more."

[0056] The flame-retardant pressure-sensitive adhesive tape of the present invention can be widely used for various purposes such as connecting protective sheets across each other, fixing a sheet to a wall or floor, easily repairing holes in a sheet (repairing by closing holes, etc.), etc. Here, examples of the sheet include various sheets for sealing packages, fixing articles, protecting equipment, and partitioning buildings.

[0057] The flame-retardant adhesive tape of the present invention can also be used as a protective sheet for blocking pollutants, for temporarily fixing fireproof sheets for construction work to floors or walls, for application to articles to be loaded onto aircraft or the like, or as a masking tape when storing aircraft or other aircraft bodies, etc. EXAMPLES

[0058] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0059] Example 1 A cloth-like material was obtained by weaving flat yarns (filaments) made of high density polyethylene.

[0060] Next, a 35 μm-thick film made of polyethylene (PE) (low-density polyethylene) was laminated on both sides of the obtained cloth-like body to obtain a base sheet (K).

[0061] Next, a coating solution was prepared by mixing polyester-based adhesive A (solution viscosity 8000 mPa s, solids content 51%) with a non-halogen-based adhesive (melamine cyanurate) as flame retardant M and crosslinking agent X (isocyanate-based crosslinking agent, "Coronate L-55E" manufactured by Tosoh Corporation), and a flame-retardant layer 50 μm thick was formed on one side of the base sheet (K). The blending amount of the flame retardant M was 40% by weight based on the total weight of the flame retardant layer. The amount of crosslinking agent X was 0.7 parts by weight based on 100 parts by weight of polyester-based pressure-sensitive adhesive A.

[0062] Furthermore, an adhesive layer consisting of acrylic adhesive B (solution viscosity 8600 mPa s, solid content 40%) and crosslinking agent Y (isocyanate crosslinking agent, "Coronate L-45E" manufactured by Tosoh Corporation) was formed by coating on the flame-retardant layer to obtain a flame-retardant adhesive tape. The thickness of the adhesive layer was 30 μm. The amount of crosslinking agent Y blended was 1.0 part by weight based on 100 parts by weight of acrylic adhesive B.

[0063] (Measurement of storage modulus) For the flame-retardant layer and the pressure-sensitive adhesive layer of Example 1, the storage modulus was measured by the following method. The pressure-sensitive adhesive layer was formed into a circular test piece having a diameter of 20 mm. The flame-retardant layer was formed into a rectangular test piece measuring 4 mm x 25 mm. The storage modulus at 23°C was obtained by measuring the adhesive layer test pieces using measuring device 1: HAAKEMARS rheometer manufactured by Thermo Fisher SCIENTIFIC (temperature: -50°C to 200°C, heating rate: 3°C / min, frequency: 1 Hz, strain: 0.1%, jig: φ20 mm parallel plate). The storage modulus at 23°C was obtained by measuring the test pieces of the flame-retardant layer using a measuring device 2: a tensile method device DVA-200 (temperature: -50°C to 200°C, heating temperature: 3°C / min, frequency: 1 Hz) manufactured by IT Measurement and Control Co., Ltd.

[0064] Example 2 A flame-retardant adhesive tape was obtained in the same manner as in Example 1, except that the amount of crosslinking agent Y in the adhesive layer was changed to 3.0 parts by weight. The storage modulus of each layer was measured in the same manner as in Example 1.

[0065] Example 3 A flame-retardant adhesive tape was obtained in the same manner as in Example 1, except that the amount of crosslinking agent X in the flame-retardant layer was changed to 2.0 parts by weight and the amount of crosslinking agent Y in the adhesive layer was changed to 3.0 parts by weight. The storage modulus of each layer was measured in the same manner as in Example 1.

[0066] Example 4 A base sheet (K) similar to that in Example 1 was obtained. Next, a coating solution was prepared by blending acrylic adhesive D (solution viscosity 10,000 mPa s, solids content 50%) with a non-halogen-based adhesive (melamine cyanurate) as flame retardant M and crosslinker Z (a chelating crosslinker, "Coponyl 5792" manufactured by Mitsubishi Chemical Corporation), and a flame-retardant layer 50 μm thick was formed on one side of the base sheet (K). The blending amount of the flame retardant M was 40% by weight based on the total weight of the flame retardant layer. The amount of crosslinking agent Z was 3.1 parts by weight based on 100 parts by weight of acrylic pressure sensitive adhesive D.

[0067] Furthermore, a pressure-sensitive adhesive layer consisting of an acrylic pressure-sensitive adhesive D and a crosslinking agent Z was formed by coating on the flame-retardant layer to obtain a flame-retardant pressure-sensitive adhesive tape. The thickness of the pressure-sensitive adhesive layer was 30 μm. The amount of crosslinking agent Z was 3.1 parts by weight based on 100 parts by weight of acrylic pressure sensitive adhesive D.

[0068] The storage modulus of each layer was measured by the following method. The pressure-sensitive adhesive layer was formed into a circular test piece having a diameter of 20 mm. The flame-retardant layer was formed into a circular test piece having a diameter of 20 mm. The storage modulus at 23°C was obtained by measuring the test pieces of the flame-retardant layer and the adhesive layer using measuring device 1: a rheometer HAAKEMARS manufactured by Thermo Fisher SCIENTIFIC (temperature: -50°C to 200°C, heating rate: 3°C / min, frequency: 1 Hz, strain: 0.1%, jig: φ20 mm parallel plate).

[0069] Comparative Example 1 A flame-retardant adhesive tape was obtained in the same manner as in Example 1, except that no crosslinking agent was added to the flame-retardant layer, and the adhesive for the adhesive layer was changed to acrylic adhesive C (solution viscosity 10000 mPa s, solid content 53%) and no crosslinking agent was added. The storage modulus of each layer was measured in the same manner as in Example 1.

[0070] <Evaluation method> The flame retardancy of the flame-retardant pressure-sensitive adhesive tapes obtained in each Example was evaluated by the following evaluation method. The results are shown in Table 1. 1. Oxygen Index In accordance with JIS K7201-2, a test piece made of flame-retardant adhesive tape was supported vertically in a combustion column to which a mixture of oxygen and nitrogen gas was supplied, and the oxygen concentration in the mixed gas was changed to measure the minimum oxygen concentration (volume %) at which the test piece could continue to burn, which was taken as the oxygen index (the unit (volume %) is omitted in the oxygen index). The criteria for continued burning are "burning for 3 minutes or more" or "burning distance of 50 mm or more."

[0071] [Table 1]

[0072] (Evaluation Results) From Table 1, in Comparative Example 1, the storage modulus of the flame-retardant layer is 2.04 × 10 7 The storage modulus of the adhesive layer is 2.3×10 4 The blood pressure was 20.4 Pa and the oxygen index was 22.6. In contrast, the flame-retardant adhesive tapes of Examples 1 to 4 had a storage modulus of the flame-retardant layer of 1.0 × 10 5 Pa or more, and the storage modulus of the adhesive layer is 5.0×10 4 It can be seen that the storage modulus is equal to or greater than 20 Pa, and the oxygen index is equal to or greater than 26. In other words, it can be seen that by satisfying the above storage modulus, a flame-retardant pressure-sensitive adhesive tape having excellent flame retardancy can be provided. In addition, in Examples 1 to 4, the storage modulus of the pressure-sensitive adhesive layer was 5.0 × 10 4 It can be seen that the storage modulus of the adhesive layer is 5.0×10 Pa or more, and thus the oxygen index is ensured to be 26 or more. 4 It is understood that a flame-retardant adhesive tape having excellent flame retardancy can be provided by having a compressive strength of 10 Pa or more. [Explanation of symbols]

[0073] 1 Cloth-like object 11 Striatum 12 Base layer 13 Bonding layer 2. Film 3. Base sheet 4. Flame-retardant layer 5 Adhesive layer

Claims

1. A base sheet is provided in which a film is laminated on one or both sides of a cloth-like material made of a filament; a flame-retardant layer and a pressure-sensitive adhesive layer are provided in this order on at least one surface of the base sheet; The flame-retardant layer has a thickness of 2 to 150 μm, and the amount of the flame retardant in the flame-retardant layer (based on solids) is 15 to 70% by weight, The pressure-sensitive adhesive layer is substantially free of a flame retardant, The combined thickness of the flame-retardant layer and the pressure-sensitive adhesive layer is 3 to 200 μm, The storage modulus of the flame-retardant layer at 23° C. is 2.0×10 ５ Pa or more, The pressure-sensitive adhesive layer has a storage modulus at 23° C. of 5.0×10 ４ Pa or more, A flame-retardant adhesive tape having an oxygen index of 26 or more.

2. 2. The flame-retardant adhesive tape according to claim 1, wherein the flame retardant is a non-halogen flame retardant.

3. 3. The flame-retardant pressure-sensitive adhesive tape according to claim 1, wherein the flame-retardant layer comprises an acrylic resin or a polyester resin.

4. A flame-retardant adhesive tape as described in claim 1 or 2, wherein the flame-retardant layer contains a polyester-based resin.

5. The flame-retardant pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein both the flame-retardant layer and the pressure-sensitive adhesive layer contain a crosslinking agent.

6. 6. The flame-retardant adhesive tape according to claim 1, wherein the cloth-like material is woven from flat yarn.

7. The flame-retardant pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the film is made of a polyolefin resin.

8. The flame-retardant pressure-sensitive adhesive tape according to any one of claims 1 to 7, wherein the film has a thickness of 10 to 80 µm.

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