adhesive tape

Abstract

The present invention relates to an adhesive tape which has a layered structure wherein an adhesive layer, a first film layer (I), a base material layer and a second film layer (II) are sequentially arranged in this order. The base material layer satisfies a specific requirement; the ratio of the thickness (a) from the first film layer (I)-side surface of the base material layer to the outer surface of the adhesive layer to the thickness (b) from the second film layer (II)-side surface of the base material layer to the outer surface of the second film layer (II), namely (a) / (b) is not less than 1.7 or not more than 0.6; and at least one layer in the layered structure contains a flame retardant (C).

Description

[Technical Field]

[0001] The present invention relates to an adhesive tape, and more particularly to an adhesive tape suitable for use in temporarily or permanently fixing aircraft members, for example. [Background technology]

[0002] BACKGROUND ART Pressure-sensitive adhesive tapes have been used to fasten components in various fields, such as electrical and electronic equipment, office automation equipment, home appliances, aircraft, ships, and vehicles. In recent years, rapid advances in research and applications of electronics, semiconductors, and magnetic technologies have led to the increasing integration, miniaturization, and performance of electrical, electronic, and office automation equipment, which has increased the risk of fire due to high temperatures and heat accumulation inside the equipment.To prevent such dangers, high levels of flame retardancy are required for the various parts inside the equipment and their adhesive materials.

[0003] Furthermore, in various fields such as aircraft and home appliances, various research efforts are being actively conducted to make plastic materials flame-retardant, and naturally, the adhesive materials used to fasten these materials are also required to have high flame retardancy.

[0004] Conventionally, flame retardancy has been imparted to flame-retardant pressure-sensitive adhesive tapes by adding a flame retardant to the adhesive layer. For example, Patent Documents 1 and 2 disclose flame-retardant pressure-sensitive adhesive tapes in which a phosphorus-based flame retardant is added to the adhesive layer. Furthermore, Patent Document 3 describes a double-sided pressure-sensitive adhesive tape in which flame retardancy is improved by changing the thickness of the adhesive layers provided on both sides of the substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-323269 [Patent Document 2] Japanese Patent Publication No. 2008-24827 [Patent Document 3] International Publication No. 2018 / 117264 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional single-sided adhesive tapes such as those disclosed in Patent Documents 1 and 2, even if a flame retardant is added to the adhesive layer, the flame retardancy is insufficient, and in order to further improve the flame retardancy, it is conceivable to increase the amount of flame retardant added. However, there is a problem that increasing the amount of flame retardant added reduces adhesive performance.

[0007] An object of the present invention is to provide an adhesive tape having an adhesive layer on one side of the tape and containing a flame retardant, which has improved flame retardancy without increasing the amount of flame retardant added. [Means for solving the problem]

[0008] However, in light of these circumstances, the present inventors have conducted extensive research and have found that the flame retardancy of an adhesive tape can be improved by configuring the multilayer support, i.e., the base layer, which has not previously received much attention, to satisfy certain requirements and by specifying the correlation between the thicknesses of each layer in the multilayer structure to a predetermined value or by configuring the multilayer structure to a predetermined configuration.

[0009] That is, the pressure-sensitive adhesive tape according to the first embodiment of the present invention is a pressure-sensitive adhesive tape having a layer structure in which a pressure-sensitive adhesive layer, a first film layer (I), a base layer, and a second film layer (II) are arranged in this order, The base material layer satisfies at least one of the following (X) and (Y): a ratio (a) / (b) of a thickness (a) from the surface of the base layer on the first film layer (I) side to the outer surface of the PSA layer to a thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less; At least one layer constituting the layer structure contains a flame retardant (C). (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0010] When the ratio (a) / (b) is 1.7 or more or 0.6 or less, the pressure-sensitive adhesive tape is more likely to curl up in a specific direction when exposed to flame than when the ratio (a) / (b) is in any other range, i.e., when the ratio (a) / (b) is greater than 0.6 and less than 1.7. In this case, if the base layer satisfies at least one of (X) and (Y) above, the base layer will shrink not only in one direction but in multiple directions when the temperature rises when exposed to flame. The pressure-sensitive adhesive tape according to the first embodiment has such a configuration, so that the pressure-sensitive adhesive tape moves away from the fire source (fire origin) before the pressure-sensitive adhesive tape catches fire, thereby suppressing flame ignition of the pressure-sensitive adhesive tape, and as a result, the flame retardancy can be further improved. When the ratio (a) / (b) is greater than 0.6 and less than 1.7, the pressure-sensitive adhesive tape does not curl up when exposed to flame, but rather moves closer to the fire source, making it more likely to catch fire.

[0011] In the pressure-sensitive adhesive tape according to the first embodiment, the first film layer (I) preferably has a thickness of 30 μm or more. In the pressure-sensitive adhesive tape according to the first embodiment, the thickness of the first film layer (I) is preferably greater than the thickness of the second film layer (II). In the pressure-sensitive adhesive tape according to the first embodiment, the pressure-sensitive adhesive layer preferably comprises a pressure-sensitive adhesive composition containing an acrylic resin (A). In the pressure-sensitive adhesive tape according to the first embodiment, the pressure-sensitive adhesive composition preferably further contains a crosslinking agent (B). In the pressure-sensitive adhesive tape according to the first embodiment, it is preferable that the pressure-sensitive adhesive layer contains the flame retardant (C), and the content of the flame retardant (C) in the pressure-sensitive adhesive layer is 1 to 25 parts by weight per 100 parts by weight of the acrylic resin (A). The pressure-sensitive adhesive tape according to the first embodiment is preferably used for fixing aircraft members.

[0012] A pressure-sensitive adhesive tape according to a second embodiment of the present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer and a base layer, The base material layer satisfies at least one of the following (X) and (Y): At least one of the pressure-sensitive adhesive layer and the base layer contains a flame retardant (C). (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0013] In the pressure-sensitive adhesive tape according to the second embodiment, it is preferable that no other layers are present between the pressure-sensitive adhesive layer and the base layer and on the surface of the base layer opposite the pressure-sensitive adhesive layer. By configuring the pressure-sensitive adhesive tape as described above, the pressure-sensitive adhesive tape is more likely to curl up in a specific direction when exposed to flame. In this case, if the base layer satisfies at least one of (X) and (Y) above, the base layer will shrink not only in one direction but in multiple directions when the temperature rises due to exposure to flame. By having such a configuration, the pressure-sensitive adhesive tape according to the second embodiment is prevented from catching fire by moving the pressure-sensitive adhesive tape away from the fire source (fire origin) before the pressure-sensitive adhesive tape catches fire, thereby improving flame retardancy.

[0014] A pressure-sensitive adhesive tape according to a third embodiment of the present invention is a pressure-sensitive adhesive tape having a layer structure in which a pressure-sensitive adhesive layer, a first film layer (I), and a base layer are arranged in this order, The base material layer satisfies at least one of the following (X) and (Y): At least one layer constituting the layer structure contains a flame retardant (C). (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0015] In the pressure-sensitive adhesive tape according to the third embodiment, it is preferable that no other layer is present on the surface of the base layer opposite the pressure-sensitive adhesive layer. By configuring the pressure-sensitive adhesive tape as described above, the pressure-sensitive adhesive tape is more likely to curl up in a specific direction when exposed to flame. In this case, if the base layer satisfies at least one of (X) and (Y) above, the base layer will shrink not only in one direction but in multiple directions when the temperature rises due to exposure to flame. By having such a configuration, the pressure-sensitive adhesive tape according to the third embodiment is moved away from the fire source (fire origin) before the pressure-sensitive adhesive tape catches fire, thereby suppressing the ignition of the pressure-sensitive adhesive tape, and as a result, flame retardancy can be improved.

[0016] A pressure-sensitive adhesive tape according to a fourth embodiment of the present invention is a pressure-sensitive adhesive tape having a layer structure in which a pressure-sensitive adhesive layer, a base layer, and a second film layer (II) are arranged in this order, wherein the ratio (a) / (b) of the thickness (a) from the surface of the base layer on the pressure-sensitive adhesive layer side to the outer surface of the pressure-sensitive adhesive layer to the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less, the base layer satisfies at least one of the following (X) and (Y), and at least one layer constituting the layer structure contains a flame retardant (C): (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0017] The pressure-sensitive adhesive tape according to the fourth embodiment preferably has no other layer between the base layer and the pressure-sensitive adhesive layer. When the base layer satisfies at least one of the above (X) and (Y), the base layer shrinks not only in one direction but also in multiple directions when exposed to flame and its temperature rises. In this case, the flame retardancy of the pressure-sensitive adhesive tape is improved when the ratio (a) / (b) of the thickness (a) from the surface of the base layer on the pressure-sensitive adhesive layer side to the outer surface of the pressure-sensitive adhesive layer to the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less. Specifically, when the ratio (a) / (b) is 1.7 or more, the surface on which the pressure-sensitive adhesive layer is located is less likely to shrink relative to the base layer. Therefore, the pressure-sensitive adhesive tape shrinks so as to curl with the surface on which the second film layer (II) is located inward, and thus moves away from the fire source more quickly, suppressing flame exposure and improving flame retardancy. Furthermore, when the ratio (a) / (b) is 0.6 or less, the surface on which the second film layer (II) is located is less likely to shrink relative to the base layer, and the adhesive tape shrinks so that it curls up with the surface on which the adhesive layer is located facing inward, thereby moving away from the fire source more quickly, suppressing flame ignition and improving flame retardancy. [Effects of the Invention]

[0018] The pressure-sensitive adhesive tape of the present invention can further improve flame retardancy without increasing the amount of flame retardant added compared to conventional methods. Therefore, the pressure-sensitive adhesive tape of the present invention is excellent in both flame retardancy and adhesiveness, and has a good balance between the two, and can be used, for example, for temporarily or permanently fixing aircraft components such as interior materials and fixtures in aircraft cabins. Specifically, the pressure-sensitive adhesive tape of the present invention can be suitably used for permanently fixing mirrors and guide signs in aircraft cabins, or for temporarily fixing decorative panels and overhead compartments. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below. However, the following description shows an example of a preferred embodiment, and the present invention is not limited to the contents of the following description. In the present invention, "(meth)acrylic" means acrylic or methacrylic, "(meth)acryloyl" means acryloyl or methacryloyl, and "(meth)acrylate" means acrylate or methacrylate. Furthermore, "acrylic resin" refers to a resin obtained by polymerizing a polymerization component containing at least one (meth)acrylate monomer. Numerical ranges defined using the symbol "~" are inclusive. For example, "2~10" means 2 to 10 inclusive. When a concentration or amount is specified, any higher concentration or amount can be related to any lower concentration or amount. For example, the descriptions "2 to 10 wt%" and "preferably 4 to 8 wt%" also include the descriptions "2 to 8 wt%" and "4 to 10 wt%." Furthermore, in this specification, a ratio by weight (percentage, part, etc.) is the same as a ratio by mass (percentage, part, etc.).

[0020] (First embodiment) The pressure-sensitive adhesive tape according to the first embodiment of the present invention will be described in detail. The pressure-sensitive adhesive tape according to the first embodiment has a layer structure in which a pressure-sensitive adhesive layer and a support layer are arranged (laminated) in this order, and the support layer has a layer structure in which a first film layer (I), a base layer, and a second film layer (II) are arranged (laminated) in this order from the pressure-sensitive adhesive layer side. That is, the pressure-sensitive adhesive tape according to the first embodiment has a layer structure in which a pressure-sensitive adhesive layer, a first film layer (I), a base layer, and a second film layer (II) are arranged (laminated) in this order. Each layer constituting the pressure-sensitive adhesive tape according to the first embodiment and each component contained therein will be described.

[0021] [Support layer] The support layer used in the adhesive tape according to the first embodiment is a multilayer support layer having a base material layer in the middle, with a first film layer (I) on one side and a second film layer (II) on the other side.

[0022] The substrate layer satisfies at least one of the following (X) and (Y). (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0023] When the substrate layer satisfies the above (X), the substrate layer includes at least a first uniaxially oriented film and a second uniaxially oriented film. A uniaxially oriented film refers to a film oriented in a uniaxial direction, for example, a film oriented in the machine direction or width direction of the film. The method for uniaxially orienting a film is not particularly limited, but an example is a method of uniaxially stretching an unstretched film. By uniaxially stretching, a uniaxially oriented film whose orientation direction is the stretching direction is obtained. As the uniaxially oriented film, it is preferable to use a film stretched in, for example, the machine direction or width direction. Methods for confirming whether a film is uniaxially oriented include infrared absorption dichroism, birefringence, SHG, X-ray diffraction, etc. Among these, infrared absorption dichroism is preferably used as a relatively simple method.

[0024] If the degree of orientation measured by infrared absorption dichroism is 0.01 or more, the film can be determined to be uniaxially oriented. The degree of orientation of a uniaxially oriented film is more preferably 0.03 or more, and particularly preferably 0.05 or more.

[0025] The material of the uniaxially oriented film is not particularly limited, but is preferably an olefin resin such as polyethylene or polypropylene, more preferably polyethylene, and particularly preferably low-density polyethylene. The thickness of the uniaxially oriented film is preferably 10 to 150 μm, more preferably 15 to 100 μm, and even more preferably 20 to 60 μm.

[0026] The first uniaxially oriented film and the second uniaxially oriented film may be the same as or different from each other in terms of material, thickness, etc., as long as the effects of the present invention are not impaired.

[0027] When the substrate layer satisfies the above (X), the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. The intersection angle is preferably 60 degrees or more, more preferably 75 degrees or more. Furthermore, the intersection angle is preferably 120 degrees or less, more preferably 105 degrees or less. When the intersection angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is within the above range, when the temperature rises upon contact with a flame, the shrinking force of the uniaxially oriented film contained in the substrate layer is more likely to act on the entire substrate. This causes the adhesive tape to bend away from the fire source (fire origin), thereby suppressing flame catching on the adhesive tape and improving flame retardancy. Furthermore, when the intersection angle is within the above range, the substrate layer is more likely to shrink in multiple directions, not just one direction, when the temperature rises upon contact with a flame.

[0028] Examples of configurations that can satisfy the above (X) include a configuration in which at least two uniaxially oriented films are bonded together, etc. More specifically, examples include a configuration in which at least two uniaxially oriented films with different stretching directions are bonded together, or a configuration in which at least two uniaxially oriented films stretched in the same direction are bonded together so that the stretching directions are different from each other.

[0029] The stretching ratio of such a stretched film is preferably 2 times or more, more preferably 3 times or more, even more preferably 4 times or more, and particularly preferably 5 times or more.

[0030] In such a configuration, the angle at which the stretching directions (orientation directions) of the uniaxially oriented films intersect can be adjusted to fall within the above-mentioned range, thereby achieving a configuration that satisfies (X) above. A particularly preferred configuration that satisfies (X) above is a configuration in which a uniaxially oriented film stretched in the machine direction of the film and a uniaxially oriented film stretched in the width direction are bonded together so that the angle at which the stretching directions intersect is 90 degrees.

[0031] In a pressure-sensitive adhesive tape, a method for checking whether the base layer satisfies the above (X) can be exemplified by taking out each film, checking whether each film is uniaxially oriented by the above-mentioned method, and determining the angle at which the orientation directions intersect by birefringence measurement or the like.

[0032] Furthermore, when the base layer satisfies the above (Y), the base layer contains at least a first flat yarn and a second flat yarn. The flat yarn is a flat thread produced by cutting a film into strips. The flat yarn is preferably stretched in the machine direction to improve strength.

[0033] When the base material layer satisfies the above (Y), the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0034] Furthermore, when the base material layer satisfies the above (Y), the base material layer preferably includes a first group of flat yarns and a second group of flat yarns, which are arranged so that the angle between the first group of flat yarns and the second group of flat yarns is 45 degrees or more and 135 degrees or less. Here, the first group of flat yarns includes the first flat yarn and one or more flat yarns arranged substantially parallel to the first flat yarn. Furthermore, the second group of flat yarns includes the second flat yarn and one or more flat yarns arranged substantially parallel to the second flat yarn.

[0035] The above-mentioned crossing angle is preferably 60 degrees or more, more preferably 75 degrees or more. Furthermore, the crossing angle is preferably 120 degrees or less, more preferably 105 degrees or less. When the crossing angle between the first flat yarn (first flat yarn group) and the second flat yarn (second flat yarn group) is within the above range, when the temperature rises upon contact with flame, the force of the flat yarns trying to shrink acts on the entire substrate, causing the adhesive tape to bend away from the fire source (fire origin), thereby suppressing flame catching on the adhesive tape and improving flame retardancy. Furthermore, when the crossing angle is within the above range, when the temperature rises upon contact with flame, the substrate layer is more likely to shrink in multiple directions, not just one direction.

[0036] An example of a configuration that can satisfy the above condition (Y) is a configuration that includes a woven fabric of flat yarns. For example, a woven fabric can be formed by weaving at least two flat yarns or groups of flat yarns so that the crossing angle is within the above range, thereby satisfying the above condition (Y). A particularly preferred configuration that satisfies the above condition (Y) is a woven fabric formed by weaving at least two flat yarns or groups of flat yarns in the warp and weft directions of the woven fabric so that the crossing angle is 90 degrees. Furthermore, when the base layer contains such a woven fabric, it is preferable that the first flat yarn or the second flat yarn in the woven fabric be arranged parallel to the machine direction of the adhesive tape. Furthermore, it is preferable that the woven fabric is one in which the intersections of the flat yarns are fixed by heat fusion to prevent misalignment. A woven fabric of flat yarns has the advantage of being able to increase the tensile strength of the adhesive tape in the longitudinal direction.

[0037] As the material for the flat yarn, olefin resins such as polyethylene and polypropylene are preferred, polyethylene is more preferred, and high density polyethylene is particularly preferred.

[0038] The thickness of the flat yarn woven fabric is preferably 10 to 150 μm, particularly preferably 15 to 100 μm, and further preferably 20 to 60 μm.

[0039] The first flat yarn (first flat yarn group) and the second flat yarn (second flat yarn group) may be the same or different in terms of material, thickness, etc., as long as the effects of the present invention are not impaired.

[0040] In a pressure-sensitive adhesive tape, a method for checking whether the base layer satisfies the above (Y) includes a method of observing with an optical microscope or the like and determining the crossing angle of the flat yarns using image analysis or the like.

[0041] Compared with woven substrates such as flat yarn woven fabrics, substrates reinforced with non-woven fibers have very low tensile strength. Therefore, in order to compensate for the tensile strength, it is conceivable to improve the tensile strength by laminating a biaxially oriented polyester film or a biaxially oriented polypropylene film using an adhesive. However, there are problems with adhesive tapes using substrates obtained by such methods, such as being difficult to tear in the width direction, and the substrate tends to be heavy because an adhesive is required to bond the warp and weft yarns.

[0042] In contrast, hand-tearability can be achieved by using a base layer that satisfies the above-mentioned (Y), such as a woven fabric of flat yarn, and a support layer laminated on both sides with a first film layer (I) and a second film layer (II). This is thought to be because laminating the woven fabric of flat yarn with a film layer such as a plastic film allows the break point to propagate smoothly, improving the linearity of the fracture surface. Furthermore, the support layer can be made lighter by laminating, for example, a thin plastic film as the first film layer (I) or the second film layer (II) to a base material layer that satisfies at least one of the above-mentioned (X) and (Y) without using an adhesive.

[0043] Materials that can be used to form the base layer, the first film layer (I), and the second film layer (II) include, for example, olefin polymers such as high-density polyethylene, linear low-density polyethylene, polypropylene, and ethylene-propylene block copolymer; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic resins; vinylidene chloride resins, etc. The materials that form the base layer, the first film layer (I), and the second film layer (II) may be different from each other, or any two or three of the layers may be the same. As a method for laminating the first film layer (I) and the second film layer (II) onto the base layer, extrusion lamination is preferred because it does not use an adhesive and can reduce weight.

[0044] The first film layer (I) and the second film layer (II) may each be a single layer or a multilayer. The thickness of the first film layer (I) and the second film layer (II) is, for example, preferably 10 to 150 μm, more preferably 20 to 100 μm.

[0045] As will be described in detail later, in the pressure-sensitive adhesive tape according to the first embodiment, the ratio (a) / (b) of the thickness (a) from the surface of the base layer on the first film layer (I) side to the outer surface of the pressure-sensitive adhesive layer to the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less. In this case, it is preferable for the thickness (a) to be greater than the thickness (b), i.e., for the ratio (a) / (b) to be 1.7 or more, in terms of the balance of the design of the pressure-sensitive adhesive tape. From this perspective, it is preferable for the thickness of the first film layer (I) to be greater than the thickness of the second film layer (II). Therefore, the thickness of the first film layer (I) is more preferably 30 μm or more, and particularly preferably 50 μm or more.

[0046] The thickness of the support layer having the first film layer (I), the base layer, and the second film layer (II) is preferably 10 to 200 μm, more preferably 50 to 170 μm, and even more preferably 60 to 150 μm. If the thickness is too thin, the hand-tearability of the adhesive tape will improve, but defects such as the introduction of wrinkles during the production of the adhesive tape will tend to increase, while if the thickness is too thick, defects during the production of the adhesive tape will decrease, but a greater force will be required to cut it, and the hand-tearability will tend to decrease.

[0047] When the pressure-sensitive adhesive tape of the present invention is used as a double-sided pressure-sensitive adhesive tape for fixing aircraft members, the weight per unit area of ​​the pressure-sensitive adhesive tape is 400 g / m 2 It is preferable that the weight per unit area of ​​the support layer is 200 g / m or less, and the support layer is also preferably light. 2 It is preferable that the weight is less than 100 g / m 2 It is more preferable that the weight per unit area of ​​the support layer is 200 g / m or less. 2 When the content is equal to or less than 100%, the flame retardancy tends to be good. The lower limit of the weight per unit area of ​​the support layer is, for example, 10 g / m 2 is preferred.

[0048] [Adhesive layer] The pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer on the first film layer (I) side of the support layer. The pressure-sensitive adhesive layer can be obtained by crosslinking (curing) a pressure-sensitive adhesive composition made of various resins.

[0049] Examples of resins that serve as the base of such pressure-sensitive adhesive compositions include synthetic rubbers such as acrylic resins, natural rubber, isoprene rubber, styrene-butadiene copolymer rubber (SBR), butadiene rubber, isobutylene-isoprene rubber, acrylic rubber, acrylonitrile-butadiene copolymer rubber, styrene-isoprene block copolymer rubber (SIS), styrene-butadiene block copolymer rubber (SBS), chloroprene rubber, and butyl rubber, as well as recycled rubber. The pressure-sensitive adhesive composition preferably contains an acrylic resin (A) because it is excellent in weather resistance, removability and heat resistance, and further the adhesive properties can be adjusted relatively easily.

[0050] The acrylic resin (A) preferably contains at least (meth)acrylic acid alkyl ester monomer (a1) units. More preferably, the acrylic resin (A) mainly contains (meth)acrylic acid alkyl ester monomer (a1) units, and further contains functional group-containing monomer (a2) units, and optionally contains other polymerizable monomer (a3) ​​units.

[0051] The acrylic resin (A) can be obtained, for example, by polymerizing a polymerization component containing at least a (meth)acrylic acid alkyl ester monomer (a1). More preferably, the polymerization component contains a (meth)acrylic acid alkyl ester monomer (a1) as the main component, further contains a functional group-containing monomer (a2), and optionally contains another polymerizable monomer (a3).

[0052] The number of carbon atoms in the alkyl group in the monomer ((meth)acrylic acid alkyl ester monomer (a1)) for forming the (meth)acrylic acid alkyl ester monomer (a1) unit is, for example, preferably 1 to 20, more preferably 1 to 12, even more preferably 1 to 8, and particularly preferably 4 to 8.

[0053] Specific examples of the (meth)acrylic acid alkyl ester monomer (a1) include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-propyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso-octyl acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, iso-stearyl acrylate, etc. These may be used alone or in combination of two or more. Among these, n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred in terms of copolymerizability, adhesive properties, ease of handling, and availability of raw materials.

[0054] The content of the (meth)acrylic acid alkyl ester monomer (a1) units in the acrylic resin (A) is preferably 10 to 100% by weight, more preferably 50 to 95% by weight, and even more preferably 70 to 95% by weight. If the content of the (meth)acrylic acid alkyl ester monomer (a1) units is too low, the adhesive strength of the pressure-sensitive adhesive layer tends to decrease.

[0055] Examples of copolymerizable monomers (functional group-containing monomers (a2)) for forming functional group-containing monomer (a2) units include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, acetoacetyl group-containing monomers, isocyanate group-containing monomers, glycidyl group-containing monomers, etc. Among these, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferred as the functional group-containing monomers (a2) because they allow efficient crosslinking reactions.

[0056] Examples of hydroxyl group-containing monomers include hydroxyalkyl acrylates such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate; caprolactone-modified monomers such as caprolactone-modified 2-hydroxyethyl (meth)acrylate; oxyalkylene-modified monomers such as diethylene glycol (meth)acrylate and polyethylene glycol (meth)acrylate; primary hydroxyl group-containing monomers such as 2-acryloyloxyethyl-2-hydroxyethyl phthalate; secondary hydroxyl group-containing monomers such as 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-chloro 2-hydroxypropyl (meth)acrylate; and tertiary hydroxyl group-containing monomers such as 2,2-dimethyl 2-hydroxyethyl (meth)acrylate. Among these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are particularly preferred as the hydroxyl group-containing monomer because of their excellent reactivity with the crosslinking agent (B). By using a hydroxyl group-containing monomer as a copolymerization monomer, the acrylic resin (A) can be made into an acrylic resin having a hydroxyl group-containing monomer unit.

[0057] Examples of carboxyl group-containing monomers include (meth)acrylic acid, acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamido-N-glycolic acid, and cinnamic acid. Among these, (meth)acrylic acid is preferred as the carboxyl group-containing monomer. By using a carboxyl group-containing monomer as a copolymerization monomer, the acrylic resin (A) can be made into an acrylic resin having a carboxyl group-containing monomer unit.

[0058] Examples of amino group-containing monomers include tert-butylaminoethyl (meth)acrylate, ethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and diethylaminoethyl (meth)acrylate.

[0059] Examples of acetoacetyl group-containing monomers include 2-(acetoacetoxy)ethyl (meth)acrylate and allyl acetoacetate.

[0060] Examples of the isocyanate group-containing monomer include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and alkylene oxide adducts thereof.

[0061] Examples of the glycidyl group-containing monomer include glycidyl (meth)acrylate and allyl glycidyl (meth)acrylate.

[0062] These functional group-containing monomers (a2) may be used alone or in combination of two or more.

[0063] The content of the functional group-containing monomer (a2) units in the acrylic resin (A) is preferably 0.01 to 30 wt%, more preferably 0.05 to 10 wt%, even more preferably 0.1 to 10 wt%, and particularly preferably 2 to 5 wt%. If the content of the functional group-containing monomer (a2) units is too low, the cohesive strength tends to decrease, resulting in a decrease in durability. On the other hand, if the content of the functional group-containing monomer (a2) units is too high, the viscosity tends to increase and the stability of the resin tends to decrease.

[0064] Examples of copolymerizable monomers for forming other polymerizable monomer (a3) ​​units (other polymerizable monomers (a3)) include (meth)acrylate compounds containing an alicyclic structure, such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; monomers containing one aromatic ring, such as phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyldiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, styrene, and α-methylstyrene; (meth)acrylic acid ester monomers containing a biphenyloxy structure, such as biphenyloxyethyl (meth)acrylate; ethoxymethyl (meth)acrylamide, n-butoxymethyl (meth)acrylamide, (meth)acryloylmorpholine, dimethyl (meth)acrylamide, diethyl (meth)acrylamide, (meth)acrylamides, and the like. (meth)acrylamide-based monomers such as N-methylol (meth)acrylamide; monomers containing an alkoxy group or an oxyalkylene group such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and polypropylene glycol mono(meth)acrylate; acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ethers, vinyl toluene, vinylpyridine, vinylpyrrolidone, dialkyl itaconate esters, dialkyl fumarate esters, allyl alcohol, acrylic chloride, methyl vinyl ketone, allyl trimethylammonium chloride, and dimethyl allyl vinyl ketone.

[0065] Among these, as the other polymerizable monomer (a3), an alicyclic structure-containing (meth)acrylate compound is preferred in terms of excellent adhesive strength to adherends with low polarity.

[0066] The content of the other polymerizable monomer (a3) ​​units in the acrylic resin (A) is preferably 40% by weight or less, more preferably 30% by weight or less, and even more preferably 25% by weight or less. If the content of the other polymerizable monomer (a3) ​​units is too high, it tends to be difficult to obtain the desired adhesive properties.

[0067] As an example, the acrylic resin (A) can be produced by copolymerizing the above-mentioned (meth)acrylic acid alkyl ester monomer (a1), if necessary, a functional group-containing monomer (a2), and other polymerizable monomers (a3) ​​as polymerization components. In order to safely and stably produce the acrylic resin (A) with any monomer composition, it is preferable to produce the acrylic resin (A) by solution polymerization.

[0068] In solution polymerization, for example, monomer components such as (meth)acrylic acid alkyl ester monomer (a1), functional group-containing monomer (a2), other polymerizable monomer (a3), and a polymerization initiator are mixed or dropped into an organic solvent, and polymerization is carried out for 0.1 to 20 hours, for example, under reflux or at 50 to 98° C. The acrylic resin (A) obtained by the above polymerization method is an organic solvent-based acrylic resin.

[0069] Examples of the polymerization initiator include azo-based polymerization initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile, which are general radical polymerization initiators, and peroxide-based polymerization initiators such as benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide and cumene hydroperoxide.

[0070] The weight-average molecular weight of the acrylic resin (A) is, for example, preferably 100,000 to 5,000,000, more preferably 300,000 to 1,500,000, and even more preferably 500,000 to 900,000. If the weight-average molecular weight is too small, durability tends to decrease, while if it is too large, production tends to become difficult.

[0071] The dispersity (weight average molecular weight / number average molecular weight) of the acrylic resin (A) is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, and particularly preferably 7 or less. If the dispersity is too high, the durability of the pressure-sensitive adhesive layer tends to decrease and foaming and the like tends to occur. In view of production limitations, the lower limit of the dispersity is preferably, for example, 1.1 or more.

[0072] The glass transition temperature of the acrylic resin (A) is, for example, preferably −80 to 10° C., more preferably −70 to −10° C., and even more preferably −65 to −20° C. If the glass transition temperature is too high, tack tends to be insufficient, and if it is too low, heat resistance tends to decrease.

[0073] The weight-average molecular weights mentioned above are those calculated in terms of standard polystyrene molecular weights. The samples were analyzed using high-performance liquid chromatography (Waters Japan, "Waters 2695 (main unit)" and "Waters 2414 (detector)") with a Shodex GPC KF-806L column (exclusion limit molecular weight: 2 × 10 7 Separation range: 100 to 2 × 10 7 Measurements can be performed using three columns in series (theoretical plate number: 10,000 / column, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm). The number average molecular weight can also be measured using a similar method. The dispersity is determined from the weight average molecular weight and number average molecular weight. The glass transition temperature is calculated using the Fox formula below. The glass transition temperature of the homopolymer obtained using the monomers constituting the acrylic resin (A) can usually be measured by a differential scanning calorimeter (DSC), but a catalog value may also be used.

[0074]

number

[0075] Tg: Glass transition temperature of the copolymer (K) Tga: Glass transition temperature of the homopolymer of monomer A (K) Wa: weight fraction of monomer A Tgb: Glass transition temperature of the homopolymer of monomer B (K) Wb: weight fraction of monomer B Tgn: Glass transition temperature (K) of the homopolymer of monomer N Wn: weight fraction of monomer N (Wa+Wb+···+Wn=1)

[0076] [Crosslinking agent (B)] The pressure-sensitive adhesive composition preferably further contains a crosslinking agent (B). The pressure-sensitive adhesive composition is preferably crosslinked and cured by the crosslinking agent (B) to form a pressure-sensitive adhesive layer.

[0077] Examples of the crosslinking agent (B) include isocyanate-based crosslinking agents, metal chelate-based crosslinking agents, epoxy-based crosslinking agents, metal salt-based crosslinking agents, metal alkoxide-based crosslinking agents, aldehyde-based crosslinking agents, non-amino resin-based amino-based crosslinking agents, urea-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, etc. The crosslinking agent (B) is preferably a metal chelate-based crosslinking agent.

[0078] The content of the crosslinking agent (B) is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, per 100 parts by weight of the acrylic resin (A). If the content is too low, the cohesive strength tends to decrease and the adhesive tends to be weak against shear. On the other hand, if the content of the crosslinking agent (B) is too high, the crosslinking reaction tends to be excessive, and the adhesive strength tends to decrease.

[0079] In particular, when the crosslinking agent (B) is a metal chelate crosslinking agent, the content thereof is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of the acrylic resin (A).

[0080] When the crosslinking agent (B) is an epoxy-based crosslinking agent, the content thereof is preferably 0.01 to 1 part by weight, more preferably 0.01 to 0.5 parts by weight, based on 100 parts by weight of the acrylic resin (A).

[0081] [Flame retardant (C)] In the pressure-sensitive adhesive tape according to the first embodiment, at least one layer constituting the layer structure contains a flame retardant (C). The layer containing the flame retardant (C) is not particularly limited as long as it is one or more of the above-mentioned pressure-sensitive adhesive layer, first film layer (I), base layer, and second film layer (II). However, from the viewpoint of maintaining the tensile strength of the pressure-sensitive adhesive tape, it is preferable that the pressure-sensitive adhesive layer contains the flame retardant (C). Note that, below, a preferred embodiment of the flame retardant (C) will be described using the case where the pressure-sensitive adhesive layer contains the flame retardant (C) as an example, but the flame retardant (C) is not limited to the following. For example, when a layer other than the pressure-sensitive adhesive layer contains the flame retardant (C), the flame retardant (C) may have a different embodiment as appropriate depending on the material of each layer, etc.

[0082] That is, in the pressure-sensitive adhesive tape according to the first embodiment, the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition) preferably contains a flame retardant (C). The flame retardant (C) may be a known flame retardant that is generally used as a flame retardant for adhesives, such as a phosphorus-based flame retardant, a metal hydroxyl-based flame retardant, a metal phosphinate-based flame retardant, a halogen-based flame retardant, a combination of a halogen-based flame retardant and antimony trioxide, a nitrogen-containing compound such as melamine cyanurate or a triazine compound, or sodium polyphosphate.

[0083] Examples of phosphorus-based flame retardants include non-halogen phosphate esters such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, 2-naphthyl diphenyl phosphate, and cresyl di-2,6-xylenyl phosphate; aromatic condensed phosphate esters such as those manufactured by Daihachi Chemical Industry Co., Ltd. under the trade names "CR-733S," "CR-741," and "PX-200"; non-halogen condensed phosphate esters such as those manufactured by Daihachi Chemical Industry Co., Ltd. under the trade names "DAIGUARD-580," "DAIGUARD-610," and "DAIGUARD-880"; amine phosphate salts such as melamine polyphosphate; and ammonium polyphosphate that is not coated with a resin or is coated with melamine or the like.

[0084] Among these, ammonium polyphosphate is preferred as the phosphorus-based flame retardant because it does not contain halogen but has a high phosphorus concentration, resulting in high flame retardancy, and can impart flame retardancy without reducing adhesive properties when added in small amounts. Furthermore, ammonium polyphosphate coated with melamine or the like is particularly preferred because it inhibits hydrolysis and has excellent moist heat resistance.

[0085] Examples of metal hydroxyl group-based flame retardants include magnesium hydroxide and aluminum hydroxide.

[0086] Examples of the metal phosphinate flame retardant include those available under the trade names "Exolit OP1230" and "Exolit OP930" manufactured by Clariant.

[0087] Examples of halogen-based flame retardants include bromine-based flame retardants such as tetrabromobisphenol A, hexabromocyclodecane, dibromodiphenyl oxide, tetrabromobisphenol A polycarbonate oligomer, brominated polystyrene, and ethylene bistetrabromophthalimide; chlorine-based flame retardants such as chlorinated paraffin and perchlorocyclopentadecane; halogen-containing phosphate esters such as tris(tribromoneopentyl)phosphate and tris(chloropropyl)phosphate; and halogen-containing condensed phosphate esters such as those sold under the trade names "CR-504L," "CR-570," and "DAIGUARD-540" by Daihachi Chemical Industry Co., Ltd.

[0088] Among these, halogen-containing flame retardants may generate toxic halogen gases or corrode metals when incinerated, and therefore, it is preferable that the flame retardant (C) is a halogen-free flame retardant.

[0089] Furthermore, it is said that a synergistic effect can be obtained by using flame retardants (C) in combination with other flame retardants having different mechanisms of action, for example, when they are made into a compound product (composite, composite material), rather than using them alone. However, in the present invention, it is preferable to use them alone, from the viewpoint of not reducing adhesive strength or compatibility with the adhesive. As the flame retardant (C), the phosphorus-based flame retardants exemplified above are particularly preferred, and ammonium polyphosphate coated with melamine or the like is particularly preferred because it provides excellent flame retardancy with little deterioration in adhesive properties, inhibits hydrolysis, and has excellent moist heat resistance.

[0090] The content of the flame retardant (C) in the pressure-sensitive adhesive layer is preferably 1 to 25 parts by weight, more preferably 1.5 to 20 parts by weight, even more preferably 2 to 15 parts by weight, and particularly preferably 3 to 8 parts by weight, relative to 100 parts by weight of the acrylic resin (A). If the content of the flame retardant (C) is too high, the adhesive properties of the adhesive tape tend to decrease and the tape weight tends to increase.

[0091] The content of the flame retardant in the entire pressure-sensitive adhesive tape is 0.5 to 5 parts by weight, more preferably 1 to 4 parts by weight, and particularly preferably 1.5 to 3 parts by weight, per 100 parts by weight of the pressure-sensitive adhesive tape. If the content of the flame retardant is too high, the adhesive properties of the pressure-sensitive adhesive tape tend to deteriorate and the tape weight tends to increase. If the content is too low, the flame retardancy tends to deteriorate.

[0092] The pressure-sensitive adhesive layer may contain, in addition to a base resin such as an acrylic resin (A), a crosslinking agent (B), and a flame retardant (C), a tackifier, an ultraviolet absorber, an antioxidant, a plasticizer, a pigment, a stabilizer, a filler, etc. as appropriate.

[0093] Examples of tackifiers include rosin-based resins, terpene-based resins, xylene-based resins, phenol-based resins, coumarone-based resins, and petroleum-based resins. When the base resin is an acrylic resin (A), the tackifier is preferably a rosin-based resin, a terpene-based resin, or a xylene-based resin, and when the base resin is a rubber-based resin, the tackifier is preferably a rosin-based resin, a terpene-based resin, or a petroleum-based resin.

[0094] As described above, the adhesive containing the organic solvent-based acrylic resin is an organic solvent-based adhesive.

[0095] [Ratio (a) / (b)] In the pressure-sensitive adhesive tape according to the first embodiment, the ratio (a) / (b) of the thickness (a) from the surface of the base layer on the first film layer (I) side to the outer surface of the pressure-sensitive adhesive layer to the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less. By setting the ratio (a) / (b) within this range, the tape is more likely to curl up in a specific direction when exposed to flame, and the adhesive tape moves away from the fire source (fire origin) before the flame ignites, thereby suppressing the tape from catching fire, compared with adhesive tapes in which the ratio (a) / (b) is greater than 0.6 and less than 1.7. In this case, by having the base layer satisfy at least one of the above (X) and (Y), the base layer contracts not only in one direction but in multiple directions when the temperature rises due to exposure to flame. That is, by setting the difference between the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) and the thickness (a) from the surface of the base layer on the first film layer (I) side to the outer surface of the adhesive layer to a ratio of 1.7 or more or 0.6 or less, when the base layer tries to shrink in multiple directions, the thicker side of thickness (a) or thickness (b) is less likely to shrink and the thinner side is more likely to shrink, causing the adhesive tape to shrink and curl up. This allows the adhesive tape to move away from the fire source more quickly, suppressing flame ignition and improving flame retardancy. Therefore, the adhesive tape according to the first embodiment has the effect of providing excellent and well-balanced flame retardancy and adhesiveness.

[0096] The "outside" in "outer surface" refers to the side of the second film layer (II) or the adhesive layer opposite the substrate layer. The "surface" does not necessarily mean the exposed surface, but refers to the interface between the adhesive layer and another layer if the adhesive layer is in contact with the other layer. For example, if a release liner with an adhesive layer is attached to the substrate, the interface with the release liner may be the surface of the adhesive layer.

[0097] In the pressure-sensitive adhesive tape according to the first embodiment, the first film layer (I) and the second film layer (II) may each have a multilayer structure, and a layer other than a plastic film may be interposed between the first film layer (I) and the substrate layer, or between the second film layer (II) and the substrate layer. When another layer is interposed, the thickness (a) or thickness (b) includes the thickness of the other layer. For example, if there is an adhesive layer between the substrate layer and the first film layer (I), the thickness (a) is the total thickness of the first film layer, the adhesive layer, and the adhesive layer. Furthermore, if the second film layer (II) is a laminated film of two films and there is an adhesive layer between the two films, the thickness (b) is the total thickness of the two film layers and the adhesive layer.

[0098] When the ratio (a) / (b) is 1.7 or more, the ratio (a) / (b) is preferably 2.0 or more, more preferably 2.5 or more, and even more preferably 3.0 or more. When the ratio (a) / (b) is 0.6 or less, the ratio (a) / (b) is preferably 0.55 or less, more preferably 0.50 or less, and even more preferably 0.40 or less. Typically, the upper limit of the ratio (a) / (b) is preferably 5.85, and the lower limit is preferably 0.30. Furthermore, it is preferable that the thickness (a) is greater than the thickness (b) in terms of the balance of the design of the adhesive tape.

[0099] The thickness of the pressure-sensitive adhesive layer is preferably 20 to 150 μm, more preferably 30 to 130 μm, even more preferably 40 to 120 μm, and particularly preferably 45 to 115 μm, from the viewpoint of providing sufficient adhesive strength to the adherend.

[0100] In order to ensure sufficient adhesion to the adherend, for example, when a test plate of a SUS-BA plate (bright annealed stainless steel plate) that has been subjected to a heat drying treatment at 175°C for 1 hour is used as the adherend, the adhesive strength of the adhesive layer is preferably 10 to 200 N / 25 mm, more preferably 15 to 150 N / 25 mm, and even more preferably 20 to 120 N / 25 mm.

[0101] Furthermore, for example, when carpet (manufactured by Lantal, for AIRCRAFT, material: wool / polyamide) is used as the adherend, the adhesive strength of the adhesive layer is preferably 3 to 100 N / 25 mm, more preferably 4 to 75 N / 25 mm, and even more preferably 5 to 50 N / 25 mm. The adhesive strength varies depending on the composition (material) and surface condition (surface roughness) of the adherend, treatment (cleaning) conditions, etc., and is not limited to the above-mentioned adhesive strength range.

[0102] If the adhesive strength is higher than the above range, the thickness of the adhesive layer will increase, which tends to make the tape heavier, and if it is lower, sufficient adhesive strength will not be obtained and the fixed member will tend to fall off easily.

[0103] In this specification, the adhesive strength is a value measured in accordance with JIS Z0237.

[0104] [Adhesive tape] If the pressure-sensitive adhesive tape according to the first embodiment has not only excellent flame retardancy but also strong adhesiveness over the medium to long term, including the initial period, it can be used, for example, for permanently fixing mirrors, carpets, etc. in aircraft cabins. Furthermore, if the pressure-sensitive adhesive tape according to the first embodiment has not only excellent flame retardancy but also appropriate adhesiveness and removability, it can be used for various applications, for example, for temporarily fixing decorative panels and overhead compartments in aircraft cabins. Thus, the pressure-sensitive adhesive tape according to the first embodiment is suitably used for fixing aircraft components.

[0105] In the pressure-sensitive adhesive tape according to the first embodiment, the total weight per unit area of ​​the support layer and the pressure-sensitive adhesive layer is 400 g / m 2 It is preferable that the weight is not more than 300 g / m 2 More preferably, it is 250 g / m or less. 2 or less, and particularly preferably 225 g / m 2 The following is the result. The lower limit of the weight is, for example, 50 g / m 2 is preferred.

[0106] The thickness of the pressure-sensitive adhesive tape according to the first embodiment is preferably 15 to 400 μm, more preferably 30 to 300 μm, and even more preferably 40 to 250 μm. If the thickness is too thick, the weight range suitable for use in aircraft tends to be exceeded, whereas if the thickness is too thin, it tends to be difficult to obtain sufficient flame retardancy and adhesiveness.

[0107] The ratio of the thickness of the adhesive layer to the thickness of the support layer of the adhesive tape according to the first embodiment (adhesive layer / support layer) is preferably 0.1-50, more preferably 0.2-25, and even more preferably 0.4-15. If this ratio is too small, the adhesive layer will be too thin relative to the support layer, which tends to make it difficult to obtain sufficient adhesive strength, and if this ratio is too large, the adhesive layer will be too thick relative to the support layer, which tends to cause inconveniences such as foaming in the adhesive layer during the production of the adhesive tape and increases costs.

[0108] [Method for manufacturing adhesive tape] The pressure-sensitive adhesive tape according to the first embodiment can be produced by a known method for producing a pressure-sensitive adhesive tape, for example, by applying a pressure-sensitive adhesive composition to one surface of a backing layer and drying the composition, and then overlaying a release liner on the surface of the pressure-sensitive adhesive layer that has been formed, or by applying a pressure-sensitive adhesive composition to one surface of a release liner and drying the composition, and then overlaying a support layer on the surface of the pressure-sensitive adhesive layer that has been formed.

[0109] When providing the pressure-sensitive adhesive layer on the support layer, the surface of the support layer may be appropriately subjected to a known and commonly used surface treatment, for example, a physical treatment such as corona discharge treatment or plasma treatment, or a chemical treatment such as a primer treatment.

[0110] Examples of release liners include plastic films made from plastics such as polyolefin resins such as polyethylene, polyester resins such as polyethylene terephthalate, vinyl acetate resins, polyimide resins, fluorine-containing resins, and cellophane; paper such as kraft paper and Japanese paper; rubber sheets made from natural rubber, butyl rubber, and the like; foam sheets obtained by foaming polyurethane, polychloroprene rubber, and the like; metal foils such as aluminum foil and copper foil; and composites of these. These may also be subjected to a surface treatment such as corona treatment on one or both sides.

[0111] Further, examples of release liners include paper obtained by laminating a film such as polyethylene onto fine paper, glassine paper, kraft paper, or clay-coated paper; paper coated with a resin such as polyvinyl alcohol or an acrylic ester copolymer; and synthetic resin films such as polyester or polypropylene coated with a release agent such as a fluororesin or silicone resin.

[0112] Among these, paper release liners are preferred because they are easy to tear by hand, and in particular, release liners with a paper basis weight of 40 to 120 g / m 2 Preferably, the paper release liner has a basis weight of 50 to 80 g / m. 2 Furthermore, the thickness of such a release liner is preferably 40 to 180 μm, more preferably 60 to 140 μm, and even more preferably 80 to 120 μm. If the thickness is too thin, wrinkles may occur during winding, making production difficult, while if the thickness is too thick, hand tearability may decrease.

[0113] A commonly used coating device can be used as a coating device for coating various sheet-like substrates with a pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive, such as a roll knife coater, a die coater, a roll coater, a bar coater, a gravure roll coater, a reverse roll coater, a dipping coater, a blade coater, etc.

[0114] The drying conditions after coating the pressure-sensitive adhesive composition may be any conditions that allow the solvent and residual monomers in the pressure-sensitive adhesive composition to be dried and removed. When a crosslinking agent (B) is used, in addition to the above, the conditions may also be any conditions that allow the functional groups of the base resin to react with the crosslinking agent (B) to form a crosslinked structure. Specific drying conditions, for example, preferably include drying at 60 to 120°C for 1 to 20 minutes. After drying, the pressure-sensitive adhesive layer is covered with a sheet-like substrate and aged to further promote the crosslinking reaction. Aging is preferably performed, for example, at 30 to 50°C for 96 hours to 7 days.

[0115] The pressure-sensitive adhesive tape according to the first embodiment may be in a roll state, or in a sheet state, or may be processed into various shapes.

[0116] The adhesive tape according to the first embodiment preferably has a high tensile strength. Specifically, for example, the strength is required to be such that the adhesive tape does not tear when pulled without distortion when affixing it to a floor or a wall, when peeled off to be re-applied, or when pulled to peel off the adhesive tape after use.

[0117] The tensile strength of the pressure-sensitive adhesive tape is preferably 20 N / 25 mm or more, more preferably 30 N / 25 mm or more, and even more preferably 50 N / 25 mm or more. The upper limit of the tensile strength is preferably 250 N / 25 mm, for example.

[0118] As described above, the pressure-sensitive adhesive tape of the present invention is preferably used for fixing aircraft components, such as interior materials and fixtures in aircraft cabins, specifically carpets, flooring materials, decorative panels, resin parts, resin sheets, and resin coatings. Particularly preferred aircraft components are carpets, flooring materials, decorative panels, and resin parts.

[0119] Examples of the carpet include well-known general carpets used in aircraft cabins, specifically carpets using nylon fibers or olefin fibers.

[0120] Examples of flooring materials include metal alloys such as aluminum alloys and titanium alloys, composite materials of glass reinforced fiber and epoxy resin, and composite materials of glass reinforced fiber and phenolic resin.

[0121] Examples of decorative panels include those obtained by laminating an aluminum alloy plate with a polyvinyl fluoride film, a polytetrafluoroethylene film, or a melamine resin film.

[0122] Examples of resin parts include parts made by molding aromatic polyamide, polycarbonate, acrylonitrile-butadiene-styrene resin, polyphenylsulfone, etc. into a desired shape.

[0123] Examples of the resin sheet include well-known general resin sheets used in aircraft, and specific examples include resin sheets made of polyvinylidene fluoride.

[0124] Examples of the resin coating film include known general resin coating films used inside aircraft, and specific examples include resin coating films made of acrylic-styrene resin, polycarbonate, fluororesin, and polyurethane.

[0125] Furthermore, the combination of aircraft components that can be bonded together using the pressure-sensitive adhesive tape according to the first embodiment is not particularly limited, and for example, carpets, flooring materials, decorative panels, resin parts, resin sheets, resin coatings, etc. can be bonded together in any appropriate combination.

[0126] (Second embodiment) The pressure-sensitive adhesive tape according to the second embodiment of the present invention will be described below. The pressure-sensitive adhesive tape according to the second embodiment has a pressure-sensitive adhesive layer and a base layer, and the base layer satisfies at least one of the following (X) and (Y), and at least one of the pressure-sensitive adhesive layer and the base layer contains a flame retardant (C). (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0127] In the pressure-sensitive adhesive tape according to the second embodiment, it is preferable that no other layer is present between the pressure-sensitive adhesive layer and the base layer and on the surface of the base layer opposite the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive tape according to the second embodiment, when the base layer satisfies at least one of the above (X) and (Y), the base layer shrinks not only in one direction but also in multiple directions when the temperature rises due to contact with flame. At that time, the surface with the pressure-sensitive adhesive layer is less likely to shrink, so the pressure-sensitive adhesive tape shrinks by curling with the surface without the pressure-sensitive adhesive layer facing inward, allowing it to move away from the fire source more quickly, suppressing flame contact and improving flame retardancy.

[0128] The base material layer and adhesive layer used in the second embodiment of the present invention are the same as those described in the first embodiment, and their preferred aspects are also the same. Furthermore, the preferred configurations, manufacturing methods, uses, etc. of the adhesive tape according to the second embodiment other than those described above are the same as those of the adhesive tape according to the first embodiment. In the second embodiment, the base material layer corresponds to the support layer described above.

[0129] (Third embodiment) The pressure-sensitive adhesive tape according to the third embodiment of the present invention will be described below. The pressure-sensitive adhesive tape according to the third embodiment has a layer structure in which a pressure-sensitive adhesive layer, a first film layer (I), and a base layer are arranged in this order, and the base layer satisfies at least one of the following (X) and (Y), and at least one layer constituting the layer structure contains a flame retardant (C): (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0130] In the pressure-sensitive adhesive tape according to the third embodiment, it is preferable that no other layer is present on the surface of the base layer opposite to the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive tape according to the third embodiment, when the base layer satisfies at least one of the above (X) and (Y), the base layer shrinks not only in one direction but also in multiple directions when the temperature rises due to contact with flame. At that time, the surface of the base layer on which the pressure-sensitive adhesive layer and the first film layer (I) are present is less likely to shrink, so the pressure-sensitive adhesive tape shrinks by curling with the surface without the pressure-sensitive adhesive layer and the first film layer (I) facing inward, thereby moving away from the fire source more quickly, suppressing flame contact and improving flame retardancy.

[0131] The base material layer, first film layer (I), and pressure-sensitive adhesive layer used in the third embodiment of the present invention are the same as those described in the first embodiment, and preferred aspects thereof are also the same. Furthermore, the preferred configurations, manufacturing methods, and uses of the pressure-sensitive adhesive tape according to the third embodiment other than those described above are the same as those of the pressure-sensitive adhesive tape according to the first embodiment. In the third embodiment, the base material layer and first film layer (I) correspond to the support layer described above.

[0132] (Fourth embodiment) A pressure-sensitive adhesive tape according to a fourth embodiment of the present invention will be described. The pressure-sensitive adhesive tape according to the fourth embodiment has a layer structure in which a pressure-sensitive adhesive layer, a base layer, and a second film layer (II) are arranged in this order, wherein the ratio (a) / (b) of the thickness (a) from the surface of the base layer on the pressure-sensitive adhesive layer side to the outer surface of the pressure-sensitive adhesive layer to the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less, the base layer satisfies at least one of the following (X) and (Y), and at least one layer constituting the layer structure contains a flame retardant (C): (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn intersects with the second flat yarn is 45 degrees or more and 135 degrees or less.

[0133] In the pressure-sensitive adhesive tape according to the fourth embodiment, it is preferable that no other layer is present between the base layer and the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive tape according to the fourth embodiment, when the base layer satisfies at least one of the above (X) and (Y), the base layer shrinks not only in one direction but also in multiple directions when the temperature rises due to contact with a flame. In this case, the flame retardancy of the pressure-sensitive adhesive tape is improved when the ratio (a) / (b) of the thickness (a) from the surface of the base layer on the pressure-sensitive adhesive layer side to the outer surface of the pressure-sensitive adhesive layer to the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less. Specifically, when the ratio (a) / (b) is 1.7 or more, the surface on which the pressure-sensitive adhesive layer is present is less likely to shrink relative to the base layer. Therefore, the pressure-sensitive adhesive tape shrinks so as to curl with the surface on which the second film layer (II) is present inward, and thus moves away from the fire source more quickly, suppressing flame contact and improving flame retardancy. Furthermore, when the ratio (a) / (b) is 0.6 or less, the surface on which the second film layer (II) is located is less likely to shrink relative to the base layer, and the adhesive tape shrinks so that it curls up with the surface on which the adhesive layer is located facing inward, thereby moving away from the fire source more quickly, suppressing flame ignition and improving flame retardancy.

[0134] In the fourth embodiment, when the ratio (a) / (b) is 1.7 or more, the ratio (a) / (b) is preferably 2.0 or more, more preferably 2.5 or more, and even more preferably 3.0 or more. When the ratio (a) / (b) is 0.6 or less, the ratio (a) / (b) is preferably 0.55 or less, more preferably 0.50 or less, and even more preferably 0.40 or less. Typically, the upper limit of the ratio (a) / (b) is preferably 5.85, and the lower limit is preferably 0.30. Furthermore, it is preferable that the thickness (a) is greater than the thickness (b) in terms of the balance of the design of the adhesive tape.

[0135] The base material layer, adhesive layer, and second film layer (II) used in the fourth embodiment of the present invention are the same as the base material layer, adhesive layer, and second film layer (II) described in the first embodiment, and their preferred aspects are also the same. Furthermore, the preferred configurations, manufacturing methods, uses, etc. of the adhesive tape according to the fourth embodiment other than those described above are the same as the preferred configurations, manufacturing methods, uses, etc. of the adhesive tape according to the first embodiment. In the fourth embodiment, the base material layer and second film layer (II) correspond to the support layer described above. [Example]

[0136] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, "parts" and "%" refer to proportions by weight.

[0137] First, an acrylic resin (A) was prepared as follows, and other raw materials for preparing a pressure-sensitive adhesive composition were also prepared. The weight average molecular weight, polydispersity, and glass transition temperature of the acrylic resin (A) were measured according to the methods described above. The viscosity was measured in accordance with JIS K5400 (1990) 4.5.3 Rotational Viscometer Method.

[0138] [Manufacturing Example 1] <Preparation of Acrylic Resin (A-1)> In a reactor equipped with a thermometer, a stirrer, and a reflux condenser, 51 parts of 2-ethylhexyl acrylate, 40 parts of butyl acrylate, 5 parts of vinyl acetate, 3.9 parts of acrylic acid, 0.1 parts of 2-hydroxyethyl methacrylate, 40 parts of ethyl acetate, and 0.18 parts of azobisisobutyronitrile as a polymerization initiator were charged, and the mixture was heated with stirring and polymerized at the ethyl acetate reflux temperature for 7 hours. After that, the mixture was diluted with ethyl acetate to obtain a 50% solution of acrylic resin (A-1). The weight average molecular weight of the resulting acrylic resin (A-1) was 600,000, the dispersity was 5.0, the viscosity was 10,000 mPa·s / 25°C, and the glass transition temperature was -59°C.

[0139] Example 1 To 100 parts of the solids content of the acrylic resin (A-1) prepared in Production Example 1, 5 parts of a melamine resin-coated ammonium polyphosphate (type II) flame retardant (manufactured by BUDENHEIM, INC., product name "TERRAJU C-80") as the flame retardant (C), 0.412 parts of an aluminum chelate crosslinker (manufactured by Mitsubishi Chemical Corporation, product name "N-2128") as the crosslinker (B), and an appropriate amount of ethyl acetate were added and mixed until homogeneous to prepare a pressure-sensitive adhesive composition. This pressure-sensitive adhesive composition was applied to a paper release liner (manufactured by Sumika Kakoshi Co., Ltd., product name "SLB-50KWD"; base paper basis weight 53 g / m²). 2 ) was coated using an applicator so that the thickness after coating was 60 μm, and dried at 80°C for 5 minutes to produce a paper release liner with an adhesive layer of 60 μm thickness.

[0140] A base layer was made of a plain-woven cloth (40 μm thick) made of stretched flat yarns made of high-density polyethylene, and low-density polyethylene was extrusion laminated to both sides of the base layer to produce a support layer in which a first film layer (I), the base layer, and a second film layer (II) were arranged in this order. The thickness of the first film layer (I) was 68 μm, and the thickness of the second film layer (II) was 24 μm. The plain-woven flat yarn cloth included a first group of flat yarns and a second group of flat yarns, and the first group of flat yarns and the second group of flat yarns were arranged so that the crossing angle between them was 90 degrees.

[0141] The adhesive surface of the paper release liner with an adhesive layer was attached to the surface of the first film layer (I) of the composite sheet (support layer), and then heat aging treatment was carried out in a 40°C dryer for 7 days to obtain an adhesive tape.

[0142] In this adhesive tape, the low-density polyethylene film on the adhesive layer side of the base layer becomes the first film layer (I), and the low-density polyethylene film on the opposite side via the base layer becomes the second film layer (II). Therefore, the thickness (a) from the surface of the base layer on the first film layer (I) side to the outer surface of the adhesive layer is 128 μm, and the thickness (b) from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 24 μm, so the ratio (a) / (b) is 5.3.

[0143] [Flammability test (FAR25)] The adhesive tape obtained above was subjected to the flammability test described in 14CFR Part 25 Appendix F Part I Section (a)(1)(ii) Amendment 25-116, and the burning time and burning length were evaluated. The burning time was evaluated as the time it took for the fire to be extinguished after the fire source was moved away from the test piece. Test pieces that were not extinguished were considered to have burned completely. Test pieces that were extinguished within 15 seconds were evaluated as passing. Test pieces that were extinguished immediately after the fire source was moved away were rated as having a burning time of 0 seconds. The fire length was 20cm or less and was deemed to have passed. The fire that was not extinguished was completely burned and the fire length was 20cm or more. The product that passed the flammability test was deemed to have passed both the burning time and burning length within the standards. The results are shown in Table 1.

[0144] Examples 2 to 4 Pressure-sensitive adhesive tapes were prepared in the same manner as in Example 1, except that the thicknesses of the first film layer (I), the second film layer (II), and the pressure-sensitive adhesive layer were changed as shown in Table 1. Flammability tests were carried out on these pressure-sensitive adhesive tapes. The results are shown in Table 1.

[0145] Example 5 A pressure-sensitive adhesive composition was prepared by adding 5 parts of a halogen-containing orthophosphate ester flame retardant (manufactured by Daihachi Chemical Industry Co., Ltd., product name "CR-900"), 0.072 parts of an aluminum chelate crosslinker (manufactured by Mitsubishi Chemical Corporation, product name "N-2128"), and an appropriate amount of ethyl acetate to 100 parts solids of the acrylic resin (A-1) prepared in Production Example 1, and mixing until homogeneous. This pressure-sensitive adhesive composition was applied to the light-release surface of a paper release liner (manufactured by Sumika Kakoshi Co., Ltd., product name "SLB-50KWD"; base paper basis weight 53 g / m²) using an applicator to a thickness of 45 µm after coating, and then dried at 80°C for 5 minutes to produce a paper release liner with a pressure-sensitive adhesive layer having a thickness of 45 µm.

[0146] A base layer was made of a plain-woven cloth (40 μm thick) made of stretched flat yarns made of high-density polyethylene, and low-density polyethylene was extrusion laminated to one side of the base layer to produce a support layer in which the base layer and second film layer (II) were arranged in that order. The thickness of the second film layer (II) was 20 μm. The plain-woven flat yarn cloth included a first group of flat yarns and a second group of flat yarns, and the first group of flat yarns and the second group of flat yarns were arranged so that the crossing angle between them was 90 degrees.

[0147] The adhesive surface of the paper release liner with an adhesive layer was attached to the surface of the base layer of the composite sheet (support layer), and then heat aging was performed in a 40°C dryer for 7 days to obtain an adhesive tape.

[0148] The thickness (a) of the pressure-sensitive adhesive tape from the surface of the base layer to the outer surface of the pressure-sensitive adhesive layer is 45 μm, and the thickness (b) of the pressure-sensitive adhesive tape from the surface of the base layer on the second film layer (II) side to the outer surface of the second film layer (II) is 20 μm, so the ratio (a) / (b) is 2.3. A flammability test was conducted on this pressure-sensitive adhesive tape, and the results are shown in Table 1.

[0149] [Comparative Examples 1 and 2] Pressure-sensitive adhesive tapes were prepared in the same manner as in Example 1, except that the thicknesses of the first film layer (I), the second film layer (II), and the pressure-sensitive adhesive layer were changed as shown in Table 1. Flammability tests were carried out on these pressure-sensitive adhesive tapes, and the results are shown in Table 1.

[0150] Comparative Example 3 An adhesive tape was produced in the same manner as in Example 1, except that the substrate layer was a single layer of biaxially oriented PET film, and the thicknesses of the first film layer (I), second film layer (II), and adhesive layer were changed as shown in Table 1. A flammability test was carried out on this adhesive tape, and the results are shown in Table 1.

[0151] [Comparative Examples 4 and 5] Pressure-sensitive adhesive tapes were produced in the same manner as in Example 1, except that the flame retardant (C) was not contained in the pressure-sensitive adhesive layer and the thicknesses of the first film layer (I), the second film layer (II) and the pressure-sensitive adhesive layer were changed as shown in Table 1. Flammability tests were carried out on these pressure-sensitive adhesive tapes. The results are shown in Table 1.

[0152] [Table 1]

[0153] The evaluation results shown in Table 1 indicate that the pressure-sensitive adhesive tapes of the examples, in which the ratio (a) / (b) of the sum (a) of the thickness of the first film layer (I) and the pressure-sensitive adhesive layer to the thickness (b) of the second film layer (II) is 1.7 or more, pass the flammability test described in 14CFR Part 25 Appendix F Part I Section (a)(1)(ii) within the standards for burn time and burn length, and therefore have excellent flame retardancy. Furthermore, the pressure-sensitive adhesive tapes of the examples have good flame retardancy even when the content of flame retardant in the pressure-sensitive adhesive layer is 5 parts, which is lower than conventional levels.

[0154] On the other hand, the pressure-sensitive adhesive tapes of Comparative Examples 1 and 2, in which the ratio (a) / (b) is less than 1.7 and exceeds 0.6, failed the flammability test described in 14CFR Part 25 Appendix F Part I Section (a)(1)(ii) Amendment 25-116 because the burn time and burn length were above the standard, indicating poor flame retardancy. Similarly, Comparative Example 3, in which a single layer of biaxially oriented PET film was used as the substrate layer, also showed poor flame retardancy. Furthermore, Comparative Examples 4 and 5, in which the ratio (a) / (b) is 1.7 or greater but no flame retardant is used, showed poor flame retardancy because either both the burn time and burn length were above the standard or one of them was above the standard and failed.

[0155] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2020-055205) filed on March 25, 2020, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0156] The pressure-sensitive adhesive tape of the present invention has excellent flame retardancy and adhesiveness, and the two properties are well balanced, making it suitable for applications involving temporary or permanent fixing of aircraft components. For example, the pressure-sensitive adhesive tape of the present invention can be used for applications involving temporary or permanent fixing of interior materials and fixtures in aircraft cabins. Specifically, the pressure-sensitive adhesive tape of the present invention can be used for applications involving permanent fixing of mirrors and guide signs in aircraft cabins, or for temporary fixing of decorative panels and overhead compartments.

Claims

1. A pressure-sensitive adhesive tape having a layer structure in which a pressure-sensitive adhesive layer, a first film layer (I), a base layer, and a second film layer (II) are arranged in this order, The substrate layer satisfies at least one of the following (X) and (Y): a ratio (a) / (b) of a thickness (a) from the surface of the base layer on the side of the first film layer (I) to the outer surface of the PSA layer to a thickness (b) from the surface of the base layer on the side of the second film layer (II) to the outer surface of the second film layer (II) is 1.7 or more or 0.6 or less; The pressure-sensitive adhesive layer contains a flame retardant (C), The content of the flame retardant (C) is 3 to 15 parts by weight relative to 100 parts by weight of the resin of the pressure-sensitive adhesive layer, and The pressure-sensitive adhesive tape has a content of the flame retardant (C) of 1.5 to 5 parts by weight per 100 parts by weight of the pressure-sensitive adhesive tape. (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn and the second flat yarn intersect is 45 degrees or more and 135 degrees or less.

2. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the first film layer (I) has a thickness of 30 μm or more.

3. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the thickness of the first film layer (I) is greater than the thickness of the second film layer (II).

4. The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive composition containing an acrylic resin (A).

5. The pressure-sensitive adhesive tape according to claim 4, wherein the pressure-sensitive adhesive composition further contains a crosslinking agent (B).

6. The pressure-sensitive adhesive tape according to any one of claims 1 to 5, which is used for fixing aircraft members.

7. A pressure-sensitive adhesive tape having a layer structure in which a pressure-sensitive adhesive layer, a base layer, and a second film layer (II) are arranged in this order, wherein a ratio (a) / (b) of a thickness (a) from a surface of the base layer on the pressure-sensitive adhesive layer side to an outer surface of the pressure-sensitive adhesive layer to a thickness (b) from a surface of the base layer on the second film layer (II) side to an outer surface of the second film layer (II) is 1.7 or more or 0.6 or less, The substrate layer satisfies at least one of the following (X) and (Y): The pressure-sensitive adhesive layer contains a flame retardant (C), The content of the flame retardant (C) is 3 to 15 parts by weight relative to 100 parts by weight of the resin of the pressure-sensitive adhesive layer, and The pressure-sensitive adhesive tape has a content of the flame retardant (C) of 1.5 to 5 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive tape. (X) At least a first uniaxially oriented film and a second uniaxially oriented film are included, and the first uniaxially oriented film and the second uniaxially oriented film are arranged so that the angle between the orientation direction of the first uniaxially oriented film and the orientation direction of the second uniaxially oriented film is 45 degrees or more and 135 degrees or less. (Y) At least a first flat yarn and a second flat yarn are included, and the first flat yarn and the second flat yarn are arranged so that the angle at which the first flat yarn and the second flat yarn intersect is 45 degrees or more and 135 degrees or less.

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