Adhesive tape, manhole structure, and method for protecting the foundation adjustment section of a manhole.

Abstract

To ensure good workability while suppressing deterioration of the manhole foundation adjustment section. [Solution] An adhesive tape comprising a base material and an adhesive layer provided on at least one side of the base material, wherein the adhesive tape is used for the purpose of protecting the foundation adjustment portion of a manhole.

Description

Technical Field

[0001] The present invention relates to an adhesive tape, a manhole structure including the tape, and a method for protecting a base adjustment part of a manhole using the tape.

Background Art

[0002] The structure of a manhole provided in an underground sewer of a sewage system is a structure provided with a bottom member such as a cylindrical concrete inclined wall or a cylindrical concrete adjustment ring on a cylindrical concrete straight wall, a base adjustment part for supporting a receiving frame to which a manhole cover is fixed, and a manhole cover fixed to the receiving frame. Generally, the base adjustment part is often constituted by filling with mortar or the like. However, when such a manhole is used for many years, the mortar constituting the base adjustment part may deteriorate. In the sewer, hydrogen sulfide is generated from sewage, and the hydrogen sulfide is oxidized to generate sulfuric acid, and this sulfuric acid is a factor causing the deterioration of the mortar. Thus, when the deterioration of the mortar progresses, the manhole cover and the receiving frame cannot be sufficiently supported, and there is a risk that the manhole cover sinks together with the receiving frame.

[0003] In order to repair the deteriorated base adjustment part, it is conceivable to reapply mortar. However, in that case, the reapplied mortar will deteriorate in a short period, and it is necessary to reapply the mortar frequently. Therefore, it is required that the mortar constituting the base adjustment part be suppressed from deteriorating even after a long period. As a method for suppressing the deterioration of mortar or concrete, for example, it is conceivable to apply a protective material to the surface of mortar or concrete. As a specific example thereof, a silicate-based surface impregnating material containing an alkali metal silicate is applied to form a base layer on the concrete, and a concrete protective material containing a lithium compound and sodium silicate and / or potassium silicate is applied on the base layer to form a glassy protective layer, thereby imparting excellent durability to the concrete (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-016947 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, applying protective coatings to the surface of mortar or concrete has the drawback of being time-consuming and not being easy to work with.

[0006] Therefore, the present invention aims to suppress deterioration of the foundation adjustment section of a manhole while maintaining good workability. [Means for solving the problem]

[0007] As a result of diligent research, the inventors of the present invention have found that the above problems can be solved by having the following configuration, and have completed the present invention. The present invention provides the following [1] to

[13] . [1] An adhesive tape comprising a base material and an adhesive layer provided on at least one side of the base material, wherein the adhesive tape is used for protecting the foundation adjustment portion of a manhole. [2] The adhesive tape according to [1], wherein the adhesive strength of the adhesive tape at 23°C is 10 N / 25 mm or more. [3] The adhesive tape according to [1] or [2], wherein the total light transmittance of the adhesive tape is 50% or more. [4] The adhesive tape according to any one of [1] to [3], wherein the adhesive layer is formed of an acrylic adhesive. [5] The adhesive tape according to any one of [1] to [4], wherein the adhesive layer is formed of a photocurable resin. [6] The adhesive tape according to any one of [1] to [5], wherein the thickness of the adhesive layer is 50 to 2500 μm. [7] The adhesive tape according to any one of [1] to [6], wherein the storage modulus of the adhesive layer at 23°C is 50,000 to 1,000,000 Pa. [8] The adhesive tape according to any one of [1] to [7], wherein the base material comprises a fluororesin, polyvinyl chloride resin, or acrylic resin. [9] The adhesive tape according to any one of [1] to [8], wherein the thickness of the base material is 20 to 300 μm.

[10] The adhesive tape according to any one of [1] to [9], which is used in an application where the adhesive tape is applied to the foundation adjustment section and to at least one of the receiving frame and the lower box.

[11] An adhesive tape comprising a base material and an adhesive layer provided on at least one side of the base material, wherein the adhesive tape is used in applications where it is adhered to a mortar surface and at least one of a metal surface and a concrete surface. A manhole structure comprising an adhesive tape as described in any of

[12] [1] to

[11] and a manhole foundation adjustment section, wherein the adhesive tape covers at least the manhole foundation adjustment section.

[13] A method for protecting the foundation adjustment portion of a manhole, comprising applying an adhesive tape, which comprises a base material and an adhesive layer provided on at least one side of the base material, to at least the foundation adjustment portion of the manhole for protection. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress deterioration of the manhole foundation adjustment section while maintaining good workability. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing one embodiment of the adhesive tape of the present invention. [Figure 2] This is a perspective view showing the foundation adjustment section of a manhole. [Figure 3] This is a cross-sectional view showing the foundation adjustment section of a manhole. [Figure 4] This is a perspective view showing how to apply adhesive tape to a mortar board. [Figure 5] This is a cross-sectional view showing a method for immersing mortar boards in sulfuric acid. [Modes for carrying out the invention]

[0010] [Adhesive tape] The adhesive tape of the present invention comprises a base material and an adhesive layer provided on at least one side of the base material, and is used to protect the foundation adjustment section of a manhole (hereinafter also simply referred to as the "foundation adjustment section"). In the present invention, by applying the adhesive tape to the foundation adjustment section, particularly the mortar constituting the foundation adjustment section, the deterioration of the foundation adjustment section is suppressed, and the need to repeatedly pour mortar or apply protective materials in a short period of time is eliminated, thus the adhesive tape of the present invention offers excellent workability.

[0011] <Total light transmittance> The adhesive tape of the present invention preferably has a total light transmittance of 50% or more. A total light transmittance of 50% or more improves visibility, making it easier to check the condition of the base adjustment part through the adhesive tape even when it is attached. From the viewpoint of improving visibility after the adhesive tape is attached, the total light transmittance is more preferably 60% or more, and even more preferably 70% or more. The higher the total light transmittance, the better, and it is sufficient if it is 100% or less, but in practical terms, it is sufficient if it is around 95% or less. The total light transmittance can be obtained by the measurement method described in the examples. Furthermore, the total light transmittance can be adjusted within the above range by appropriately selecting the thickness of the adhesive layer and substrate, the composition of the adhesive layer, and the material of the substrate.

[0012] <Adhesive strength> The adhesive tape of the present invention preferably has an adhesive strength of 10 N / 25 mm or more at 23°C, more preferably 11 N / 25 mm or more, and even more preferably 20 N / 25 mm or more. When the adhesive strength at 23°C is equal to or greater than the above lower limit, the adhesion between the adhesive tape and the foundation adjustment part increases, making it easier to suppress the deterioration of the foundation adjustment part by the adhesive tape. The higher the adhesive strength at 23°C, the better, but in practical terms, it is 200 N / 25 mm or less. The adhesive tape of the present invention preferably has an adhesive force of 5 N / 25 mm or more, more preferably 10 N / 25 mm or more, and even more preferably 20 N / 25 mm or more at one or both of 0°C and 40°C. When the adhesive force is not less than the above lower limit value, it can stably adhere to the adherend even in the construction environment in summer or winter. Although the higher the adhesive force, the better, in practical use, it is 200 N / 25 mm or less.

[0013] The adhesive force of the adhesive tape is measured as follows. The adhesive tape of the present invention is attached to a stainless steel plate (SUS plate) to prepare a sample for evaluating the adhesive force. At this time, the sample for evaluating the adhesive force is prepared by attaching it so that the surface of the SUS plate and the adhesive layer of the adhesive tape are in contact. The size of the adhesive tape is 100 mm in length and 25 mm in width. The bonding of the adhesive tape to the SUS plate is carried out by reciprocating a 2 kg roller at a speed of 10 ± 0.5 mm / s twice. For the sample for evaluating the adhesive force obtained by the above procedure, the adhesive force is measured by a peeling test of the adhesive tape. The peeling test is carried out by a tensile testing machine under the conditions of 0°C, 23°C, or 40°C and 50 RH%, with a peeling angle of 90° and a speed of 300 mm / min, and pulling for 60 mm or more. The interval average value of the detected load (N) is taken as the adhesive force. In addition, when measuring the adhesive force, if there is a high possibility that the base material breaks due to insufficient base material strength, the base material may be appropriately changed to measure the adhesive force in order to prevent breakage. In that case, for example, it is preferable to use a PET film.

[0014] <Base material> As the base material constituting the adhesive tape of the present invention, it is preferable to use one having acid resistance. Since the base material has acid resistance, excellent acid resistance can be imparted to the adhesive tape. Therefore, even when the adhesive tape is exposed to hydrogen sulfide generated in the manhole, the deterioration of the adhesive tape is suppressed, and it becomes easier to protect the foundation adjustment part of the manhole.

[0015] A resin film is preferred as the base material, and as the resin constituting the resin film, for example, from the viewpoint of acid resistance, polyolefin resins, polyester resins, acrylic resins, fluororesins, polycarbonate resins, polyvinyl chloride resins, AES resins, ASA resins, etc., can be preferably used. These resins may be used individually or in combination of two or more. As the above resin, from the viewpoint of easily imparting excellent weather resistance and conformability to irregularities on the surface of the adherend to the adhesive tape, it is preferable that the resin contains a fluororesin, polyvinyl chloride resin, or acrylic resin, and more preferably an acrylic resin. That is, the base material is preferably a fluororesin film composed of a fluororesin, a polyvinyl chloride resin film composed of a polyvinyl chloride resin, or an acrylic resin film composed of an acrylic resin, and among these, an acrylic resin film is more preferable. The resin film used as the base material may be single-layer or multi-layer. In the case of multi-layer, only resin films of the same type may be laminated, or two or more types of resin films may be laminated.

[0016] The thickness of the substrate is preferably 20 to 300 μm, more preferably 30 to 200 μm, and even more preferably 40 to 150 μm. The substrate can function as a support when its thickness is above the lower limit. Furthermore, by making the thickness below the upper limit, it becomes easier to improve the conformability of the adhesive tape to the base adjustment section.

[0017] <Adhesive layer> The adhesive tape of the present invention comprises an adhesive layer on at least one surface of the substrate. The adhesive layer will be described in detail below.

[0018] (Adhesive) The adhesive layer is formed by an adhesive. The type of adhesive is not particularly limited, but examples include acrylic adhesives, rubber adhesives, urethane adhesives, and silicone adhesives. These may be used individually or in combination. Furthermore, it is preferable that the adhesive layer be formed from a photocurable resin. By using a photocurable resin for the adhesive layer, a relatively large thickness, such as 100 μm or more, can be achieved. As a result, it becomes easier to conform to the irregularities of the adherend surface, increasing the adhesion area with the adherend and suppressing the risk of peeling. The adhesive layer is more preferably formed from an acrylic adhesive among photocurable resins. The adhesive layer can be formed by using a photocurable polymer as the main polymer constituting the adhesive; for example, in the case of an acrylic adhesive, the acrylic polymer can be of photocurable type.

[0019] (Acrylic adhesive) Acrylic adhesives are adhesives that contain an acrylic polymer obtained by polymerizing polymerizable monomers, including (meth)acrylate alkyl ester monomer (A). In this specification, the term "(meth)acrylate alkyl ester" refers to a concept that includes both alkyl acrylates and alkyl methacrylates, and the same applies to other similar terms. Furthermore, the term "polymerizable monomer" refers to a concept that may include not only compounds without repeating units, but also compounds copolymerized with (meth)acrylate alkyl ester monomers (A), including olefin polymers (C) described later, in which the monomer itself has repeating units.

[0020] ((meth)acrylate alkyl ester monomer (A)) The alkyl ester monomer (A) is an ester of (meth)acrylic acid and an aliphatic alcohol, wherein the alkyl group of the aliphatic alcohol has preferably 2 to 14 carbon atoms, more preferably 4 to 10 carbon atoms. Having the alkyl group within this range makes it easier to increase tackiness and to adjust the storage modulus of the adhesive at 23°C to a predetermined range. Furthermore, the alkyl ester monomer (A) is preferably an ester of acrylic acid and an aliphatic alcohol.

[0021] Specific examples of alkyl (meth)acrylate monomers (A) include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, and tetradecyl (meth)acrylate. Among these, n-butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-octyl (meth)acrylate are preferred, with n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, or combinations thereof being more preferred. Considering adhesion at low temperatures, the use of 2-ethylhexyl (meth)acrylate alone is even more preferable. (Meth)acrylate alkyl ester monomer (A) may be used alone or in combination of two or more types.

[0022] The constituent units derived from the alkyl methacrylate monomer (A) constitute the main component in the adhesive layer, and their content is generally 30% by mass or more, preferably 50% by mass or more, and more preferably 70% by mass or more, based on the total amount of the adhesive layer. In this way, increasing the content of the alkyl methacrylate monomer (A) makes it possible to impart the desired adhesive strength to the adhesive layer. Furthermore, the above content of the constituent units derived from the alkyl methacrylate monomer (A) is, for example, 97% by mass or less, preferably 95% by mass or less, and more preferably 90% by mass or less, in order to include a certain amount or more of other components. Furthermore, the content of constituent units derived from (meth)acrylate alkyl ester monomer (A) in the adhesive layer is substantially the same as the content of (meth)acrylate alkyl ester monomer (A) in the adhesive composition described later, and can therefore be expressed interchangeably. The same applies to components other than component (A), such as components (B) and (C) described below.

[0023] (Polar group-containing vinyl monomer (B)) The polymerizable monomer preferably contains a polar group-containing vinyl monomer (B) in addition to an alkyl (meth)acrylate monomer (A). The polar group-containing vinyl monomer (B) has a polar group and a vinyl group. Using the polar group-containing monomer (B) makes it easier to improve the adhesion to the adherend. Examples of polar group-containing vinyl monomers (B) include vinyl carboxylate esters such as vinyl acetate, vinyl group-containing carboxylic acids such as (meth)acrylic acid and itaconic acid, and their anhydrides, vinyl monomers having hydroxyl groups such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone-modified (meth)acrylate, polyoxyethylene (meth)acrylate, and polyoxypropylene (meth)acrylate, and nitrogen-containing vinyl monomers such as (meth)acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyllauricolactam, (meth)acryloylmorpholine, (meth)acrylamide, dimethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylamide, and dimethylaminomethyl (meth)acrylate. Among these, from the viewpoint of improving adhesion to the base preparation part which is the adherend, vinyl group-containing carboxylic acids such as (meth)acrylic acid and itaconic acid, and their anhydrides are preferred, (meth)acrylic acid is more preferred, and acrylic acid is even more preferred. These polar group-containing vinyl monomers (B) may be used alone or in combination of two or more.

[0024] When using polar group-containing vinyl monomer (B), the content of constituent units derived from polar group-containing vinyl monomer (B) in the adhesive layer is preferably 1 to 15 parts by mass, more preferably 2 to 10 parts by mass, even more preferably 3 to 10 parts by mass, and even more preferably 3 to 6 parts by mass, per 100 parts by mass of constituent units derived from alkyl (meth)acrylate monomer (A). By keeping the content of polar group-containing vinyl monomer (B) below the above upper limit, it becomes easier to improve the adhesive strength of the adhesive tape, especially the low-temperature adhesive strength, and by keeping it above the above lower limit, it can be applied with good workability even in summer environments.

[0025] (Olefin polymer (C)) The polymerizable monomer preferably further contains an olefin polymer (C) having a polymerizable bond at one end. Using such an olefin polymer (C) makes it easier to improve the adhesive strength of the adhesive tape. A polymerizable bond refers to an unsaturated carbon-carbon bond that can polymerize with polymerizable monomers. Examples include unsaturated double bonds, and preferably (meth)acryloyl groups. Examples of olefin polymers (C) include polyolefins having a (meth)acryloyl group at one end. Polyolefins are polymers of aliphatic hydrocarbon compounds having double bonds, such as ethylene, propylene, butane, butadiene, and isoprene, or their hydrogenated products.

[0026] Examples of polyolefins having a (meth)acryloyl group at one end include polyethylene having a (meth)acryloyl group at one end, prepared by reacting polyethylene having an epoxy group at one end with (meth)acrylic acid. Other examples include polybutadiene having a (meth)acryloyl group at one end or its hydrogenated products, with "L-1253" manufactured by Kuraray Co., Ltd. being a commercially available example.

[0027] The olefin polymer (C) preferably has a number-average molecular weight of 500 to 20,000, more preferably 1,000 to 10,000. The number-average molecular weight can be measured by gel permeation chromatography (GPC) and calculated using a calibration curve for standard polystyrene. Furthermore, the content of constituent units derived from the olefin polymer (C) in the adhesive layer is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 4 to 15 parts by mass, per 100 parts by mass of constituent units derived from the alkyl (meth)acrylate monomer (A).

[0028] (Crosslinking agent (D)) The polymerizable monomer preferably further contains a crosslinking agent. Examples of crosslinking agents include polyfunctional monomers having two or more vinyl groups, and preferably polyfunctional (meth)acrylates having two or more (meth)acryloyl groups. Using polyfunctional monomers makes it easier to adjust the tackiness of the adhesive layer to an appropriate range. The polyfunctional (meth)acrylate is not particularly limited and includes hexanediol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, proxiated trimethylolpropane triacrylate, proxiated glyceryl triacrylate, neopentyl glycol adipate diacrylate, and polymers such as polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and liquid hydrogenated 1,2-polybutadiene di(meth)acrylate. Among these polyfunctional (meth)acrylates, polymers or difunctional alkyl acrylates are preferred, with difunctional alkyl acrylates being more preferred. Liquid hydrogenated 1,2-polybutadiene diacrylate is more preferred as a polymer, and hexanediol di(meth)acrylate is more preferred as a difunctional alkyl acrylate. Examples of commercially available liquid hydrogenated 1,2-polybutadiene diacrylate include "TEAI-1000" manufactured by Nippon Soda Co., Ltd., and examples of commercially available bifunctional alkyl acrylate include "NK Ester A-HD-N" manufactured by Shin Nakamura Chemical Industry Co., Ltd. Furthermore, the content of the crosslinking agent-derived structural units in the adhesive layer is preferably 0.01 to 4 parts by mass, more preferably 0.02 to 3 parts by mass, even more preferably 0.03 to 2 parts by mass, even more preferably 0.03 to 1 part by mass, even more preferably 0.03 to 0.5 parts by mass, and particularly preferably 0.03 to 0.1 parts by mass, per 100 parts by mass of structural units derived from (meth)acrylate alkyl ester monomer (A). When the crosslinking agent content is within the above range, it becomes easier to adjust the adhesive strength of the adhesive layer, especially the low-temperature adhesive strength, to an appropriate range.

[0029] (Adhesive-forming resin) Acrylic adhesives may contain a tackifying resin to improve adhesive strength. Preferred tackifying resins include those with low polymerization inhibitory properties, such as hydrogenated terpene resins, hydrogenated rosin, disproportionated rosin resins, and petroleum resins. Among these, hydrogenated resins are preferred, and hydrogenated petroleum resins are particularly preferred, as tackifying resins with many double bonds inhibit the polymerization reaction. The softening point of the tackifying resin should be approximately 95°C or higher from the viewpoint of improving the cohesive force and adhesive strength of the adhesive, but it is preferable to include resins with a softening point of 120°C or higher. Furthermore, from the viewpoint of improving adhesion to the adherend, for example, a combination of resins with a softening point of 95°C or higher but less than 120°C and resins with a softening point of 120°C or higher but less than 150°C may be used. The softening point should be measured by the ring-and-ball method specified in JIS K2207. The content of the tackifying resin in the acrylic adhesive is preferably 3 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 7 to 25 parts by mass, per 100 parts by mass of constituent units derived from the alkyl ester monomer (A) (meth)acrylate.

[0030] (fine particles) Acrylic adhesives may contain fine particles. The inclusion of fine particles can improve adhesive strength. Examples of fine particles include inorganic hollow particles such as glass balloons, shirasu balloons, and fly ash balloons; organic hollow particles made of polymethyl methacrylate, acrylonitrile-vinylidene chloride copolymer, polystyrene, and phenolic resin; inorganic fine particles such as glass beads, silica beads, and synthetic mica; and organic fine particles such as ethyl polyacrylate, polyurethane, polyethylene, and polypropylene. The content of fine particles in the acrylic adhesive is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 10 parts by mass, and even more preferably 0.5 to 5 parts by mass, per 100 parts by mass of constituent units derived from the alkyl ester monomer (A) (meth)acrylate.

[0031] (Other ingredients) The acrylic adhesive used in the adhesive layer may also contain various additives conventionally used in adhesives, such as plasticizers, softeners, pigments, dyes, dispersants, photopolymerization initiators, and flame retardants, in addition to the components mentioned above.

[0032] (Rubber-based adhesive) Rubber-based adhesives contain a rubber component and a tackifying resin, and it is preferable to use a styrene-isoprene block copolymer as the rubber component. The styrene-isoprene block copolymer has a diblock ratio of preferably 25 to 70% by mass, more preferably 30 to 65% by mass, and even more preferably 45 to 60% by mass. Here, a diblock refers to a diblock composed of styrene and isoprene. Setting the diblock ratio within the above range makes it easier to increase the adhesive strength. In addition to diblocks, styrene-isoprene block copolymers also include those having three or more blocks, such as triblocks composed of styrene, isoprene, and a styrene block.

[0033] The amount of styrene in the styrene-isoprene block copolymer is not particularly limited, but is preferably 14 to 24% by mass, and more preferably 15 to 18% by mass. When the amount of styrene is 14% by mass or more, it tends to become an adhesive with high cohesiveness. On the other hand, when the amount of styrene is 24% by mass or less, the cohesive force becomes of an appropriate magnitude, making it easier to exhibit adhesiveness. The molecular weight of the styrene-isoprene block copolymer is not particularly limited, but is preferably 100,000 to 400,000 by weight-average molecular weight, and more preferably 150,000 to 250,000. Here, weight-average molecular weight refers to the molecular weight measured as polystyrene-equivalent molecular weight by GPC (gel permeation chromatography).

[0034] Various tackifying resins can be used in rubber-based adhesives, but petroleum-based resins, terpene resins, and coumarone resins are preferred. The tackifying resin may be used alone or in combination of two or more, but it is preferable to use a combination of petroleum-based resin and at least one selected from terpene resins and coumarone resins. Such a combination of tackifying resins makes it easier to improve the adhesive strength. Examples of petroleum-based resins include aliphatic petroleum resins (C5 petroleum resins), alicyclic petroleum resins, and aromatic petroleum resins, with aliphatic petroleum resins being preferred from the viewpoint of compatibility with styrene-isoprene block copolymers. Furthermore, it is preferable to use petroleum-based resins with a softening point of approximately 90 to 120°C. Furthermore, while terpene resins with a softening point of approximately 80 to 120°C can be used, those with a softening point of less than 100°C are preferred from the viewpoint of ensuring adhesive strength. In addition, for coumarone resins, those with a softening point of preferably 110 to 130°C, and more preferably 115 to 125°C, are used to ensure cohesive strength.

[0035] The tackifying resin is preferably in an amount of 60 to 250 parts by mass, more preferably 100 to 200 parts by mass, and even more preferably 110 to 180 parts by mass, per 100 parts by mass of the rubber component. By setting the amount of tackifying resin within the above range, it becomes possible to improve the cohesive force and impart appropriate tackiness. Furthermore, when using petroleum-based resin in combination with at least one selected from terpene resin and coumarone resin, the amount of petroleum-based resin is preferably 50 to 200 parts by mass, preferably 60 to 150 parts by mass, and more preferably 60 to 110 parts by mass, per 100 parts by mass of rubber component. On the other hand, the amount of terpene resin is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, per 100 parts by mass of rubber component. Furthermore, the amount of coumarone resin is preferably 10 to 60 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of rubber component. The rubber-based adhesive may contain the aforementioned fine particles, similar to the acrylic-based adhesive, and may also contain softeners, antioxidants, fillers, etc., as needed.

[0036] (Urethane-based adhesive) The urethane adhesive is not particularly limited and includes, for example, a urethane resin obtained by reacting at least a polyol with a polyisocyanate compound. Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, and polycaprolactone polyol. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate. These urethane adhesives may be used individually or in combination of two or more. Furthermore, as a urethane-based adhesive, a urethane resin obtained by reacting a polyurethane polyol with a polyfunctional isocyanate-based curing agent may be used. Examples of polyurethane polyols include those obtained by reacting the above-mentioned polyol with a polyisocyanate compound, or those obtained by reacting a polyol with a polyisocyanate compound and a chain extender such as a diamine. As the polyfunctional isocyanate-based curing agent, any compound having two or more isocyanate groups is acceptable, and the above-mentioned isocyanate compounds can be used. The urethane-based adhesive may contain the above-mentioned fine particles in addition to the urethane resin, and may also contain, if necessary, tackifying resins, softeners, antioxidants, fillers, etc.

[0037] (Silicone-based adhesive) Examples of silicone-based adhesives include addition reaction type, peroxide curing type, or condensation reaction type silicone-based adhesives. Among these, addition reaction type silicone-based adhesives are preferred from the viewpoint of being able to cure at low temperatures and in a short time. Addition reaction type silicone-based adhesives cure when the adhesive layer is formed. When an addition reaction type silicone-based adhesive is used as the silicone-based adhesive, the silicone-based adhesive may contain a catalyst such as a platinum catalyst. Furthermore, silicone-based adhesives may contain fine particles, and may also contain crosslinking agents and various additives to control adhesive strength.

[0038] (Method for manufacturing acrylic adhesive and adhesive layer) The adhesive layer can be manufactured using a general method for forming an adhesive layer. Below, we will describe in detail the manufacturing method of an acrylic adhesive and an adhesive layer, using the case where the adhesive is an acrylic adhesive and of the photocurable type as an example. Acrylic adhesives can be obtained by irradiating an adhesive composition containing the polymerizable monomers described above, and other components other than polymerizable monomers, such as tackifying resins and fine particles, which are used as needed, with light to polymerize the polymerizable monomers. More specifically, first, polymerizable monomers, tackifying resins (if necessary), and other components such as fine particles are placed in a reaction vessel such as a glass container and mixed to obtain an adhesive composition. Next, to remove dissolved oxygen from the adhesive composition, an inert gas such as nitrogen gas is generally supplied to purge the oxygen. Then, the adhesive composition is applied to a release sheet, or after applying it to a substrate, light is irradiated to polymerize the polymerizable monomers and an adhesive layer can be obtained. At this time, the adhesive strength can be adjusted to an appropriate range by adjusting the light irradiation intensity. It is preferable that the steps from applying or impregnating the adhesive composition to irradiating it with light be carried out under an inert gas atmosphere or in a state where oxygen is blocked by a film or the like. In this manufacturing method, the adhesive composition obtained by mixing each component may be prepolymerized before being applied to a release sheet or support in order to increase its viscosity.

[0039] (Storage modulus) Preferably, the storage modulus of the adhesive layer at 23°C is 50,000 to 1,000,000 Pa. When the storage modulus of the adhesive layer at 23°C is within this range, it becomes easier to set the adhesive strength within an appropriate range, the adhesive layer is less likely to be damaged even when subjected to external impacts, and deterioration of the foundation adjustment part is more easily suppressed. From the viewpoint of setting the adhesive strength within an appropriate range while suppressing deterioration of the foundation adjustment part, the storage modulus of the adhesive layer at 23°C is more preferably 200,000 to 800,000 Pa, and even more preferably 300,000 to 700,000 Pa. The storage modulus at 40°C should be 50,000 Pa or higher, and more preferably 100,000 Pa or higher. Keeping it within this range allows for easy application to the adjustment part even in high-temperature environments such as summer. The storage modulus at 0°C should be 1.5 million Pa or less, more preferably 1.3 million Pa or less, and even more preferably 1.1 million Pa or less. Keeping it within this range ensures that the material exhibits strong adhesion to the adjustment part even in low-temperature environments such as winter. The storage modulus can be calculated by measuring the dynamic viscoelastic spectrum.

[0040] (Thickness) The thickness of the adhesive layer is preferably 50 to 2500 μm, more preferably 80 to 2200 μm, and even more preferably 100 to 1500 μm. By setting the thickness to above the lower limit, a certain level of adhesive strength is achieved, making it easier to cover the base adjustment area with adhesive tape and suppress deterioration of the base adjustment area. Furthermore, by setting the thickness of the adhesive layer to below the upper limit, it becomes easier to improve the transparency of the adhesive tape and the conformability of the adhesive tape to the adherend.

[0041] <Composition of adhesive tape> In the present invention, as shown in Figure 1, the adhesive tape 10 is preferably a single-sided adhesive tape having a base material 12 and an adhesive layer 11 provided on one side of the base material 12. Such a configuration of the adhesive tape makes it easier to apply and prevents dust from inside the manhole from adhering to the adhesive tape after application. The adhesive tape is used by attaching it to the object to be adhered, with the surface 11A of the adhesive layer 11 serving as the adhesive surface. Furthermore, although not shown in the illustration, the adhesive tape may also be a double-sided adhesive tape having a base material and adhesive layers on both sides of the base material.

[0042] The adhesive tape of the present invention may have a release sheet attached to the surface of the adhesive layer. The release sheet is preferably peeled off from the adhesive layer before the adhesive tape is used, exposing the adhesive layer, which then adheres to the substrate. More specifically, the release sheet is preferably attached to the surface 11A of the adhesive layer that is opposite to the surface on which the substrate is provided. A resin film is suitable as the release sheet, but it is preferable that the surface that adheres to the adhesive layer is a release-treated surface that has been treated with a silicone release agent or the like. Furthermore, if a release liner is attached, the various physical properties of the adhesive tape, such as the total light transmittance, shall be those measured after the release liner has been removed.

[0043] <How to use> As described above, the adhesive tape of the present invention is used to protect the foundation adjustment portion of a manhole. Specifically, it is preferable that the adhesive tape be applied to at least the foundation adjustment portion of the manhole. That is, the present invention can also provide a manhole structure comprising an adhesive tape and a manhole foundation adjustment portion covered by the adhesive tape. Furthermore, the present invention can also provide a method for protecting the foundation adjustment portion of a manhole by applying adhesive tape to at least the foundation adjustment portion of the manhole. Here, as shown in Figure 2 or 3, it is preferable that the adhesive tape 10 be attached to at least one of the mortar 26 constituting the foundation adjustment section, and the receiving frame 20 and the lower manhole 27. That is, it is preferable that the adhesive tape of the present invention be used by being attached to at least one of the mortar surface constituting the foundation adjustment section, and the metal surface constituting the receiving frame and the concrete surface constituting the lower manhole. Furthermore, it is even more preferable that the adhesive tape of the present invention be used by being attached to any of the mortar 26, the receiving frame 20, and the lower manhole 27, i.e., the mortar surface, the metal surface, and the concrete surface. By attaching the adhesive tape to all of these, the foundation adjustment section of the manhole becomes even more easily protected. The foundation adjustment section is a component that supports the receiving frame on which the manhole cover is fixed.

[0044] The structure of a manhole to which the adhesive tape of the present invention is attached will be described in more detail below. As shown in Figure 2 or 3, the manhole consists of a receiving frame 20 to which the manhole cover 28 is fixed, and a lower box 27, which are connected by predetermined fasteners consisting of fastening bolts 21, fastening nuts 22, frame holders 23, bolt sleeves 25, etc. The lower box 27 is composed of, for example, a cylindrical concrete inclined wall, or a concrete inclined wall and a cylindrical concrete adjustment ring. The receiving frame 20 and the lower box 27 are fastened together with fasteners to form a cavity, and mortar 26 is filled into the cavity between the receiving frame 20 and the lower box 27. The frame holder 23 consists of an upper holder 23A and a lower holder 23B fixed to the fastening bolt 21, and holds the receiving frame 20. A holder sleeve 24 made of an elastic material such as rubber is attached to the outer circumference of the lower holder 23B. A bolt sleeve 25 is attached to the outer circumference of the fastening bolt 21 below the lower holder 23B to protect the fastening bolt 21 from the mortar 26.

[0045] In the manhole, by filling the above-mentioned cavity with mortar 26, the mortar 26 acts as a connector between the receiving frame 20 and the lower box 27, preventing the manhole cover 28 from collapsing together with the receiving frame 20 even when a vehicle or other object passes over the manhole and puts a load on the manhole cover 28. The mortar 26 is formed in a cylindrical shape, with its inner surface exposed to the inside of the manhole. The shape of the mortar 26 can be cylindrical, or it can be a shape other than cylindrical, such as a square cylinder.

[0046] In the present invention, it is preferable that the adhesive tape 10 be attached to at least the mortar 26 as the adherend. Here, the adhesive tape 10 is preferably attached to the inner circumferential surface of the mortar 26. This makes it possible to suppress the deterioration of the mortar 26 from hydrogen sulfide generated in the manhole, or from sulfuric acid generated when hydrogen sulfide condenses in the manhole. The adhesive tape 10 may be attached so as to cover a part of the mortar 26, or it may be attached so as to completely cover the mortar 26. Furthermore, as described above, it is preferable that a part of the adhesive tape 10 adheres to at least one of the receiving frame 20 and the lower manhole 27, in which case, for example, it is preferable that it be attached from the inner circumferential surface of the receiving frame 20 to the inner circumferential surface of the lower manhole 27, as shown in Figure 3.

[0047] Furthermore, the above-mentioned manhole may be constructed by injecting mortar 26 into the cavity between the pre-installed receiving frame 20 and the lower manhole 27, and then attaching adhesive tape 10 to the inner surface of the mortar. In this case, the adhesive tape 10 should be attached after at least a portion of the mortar has hardened. Specifically, it is preferable to attach the adhesive tape 10 to the mortar after it has hardened to a degree that allows for the application of the adhesive tape 10. The manhole construction described above may be applied to newly installed manholes or to repair existing manholes; for example, it may be applied when replacing the mortar in an existing manhole. Furthermore, when repairing a manhole, it may be acceptable to simply reapply adhesive tape without removing the existing mortar. In the above description, adhesive tape has been used to protect the foundation adjustment section of a manhole, but it may be used for other purposes. However, even in those cases, the adhesive tape is often applied to a mortar surface and used for purposes such as protecting the mortar, and preferably applied to mortar and at least one of a metal surface and a concrete surface. [Examples]

[0048] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0049] [Evaluation Method] In the examples and comparative examples, the adhesive tapes were evaluated using the following evaluation method.

[0050] <Total light transmittance> The adhesive tapes obtained in each example and comparative example were processed into measurement samples measuring 50 mm in width and 30 mm in length, and the total light transmittance was measured. The total light transmittance was measured in accordance with JIS K7361-1. Specifically, it was measured using a haze meter (Haze Meter NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd.) under conditions of 23°C and 50% humidity.

[0051] <Storage modulus at 0°C, 23°C, and 40°C> The storage modulus of the adhesive layer of the adhesive tape was calculated by measuring the dynamic viscoelastic spectrum using a dynamic viscoelasticity measuring device (manufactured by IT Measurement Control Co., Ltd., product name "DVA-200") under the following conditions: shear mode: 10 Hz, strain: 0.1%, temperature range: -100°C to 100°C, and heating rate: 10°C / min. The storage modulus of the adhesive layer was also measured separately after peeling it from the substrate.

[0052] <Adhesive strength> 1. Sample preparation The adhesive tapes obtained in each example and comparative example were cut to a width of 25 mm and a length of 100 mm, and then left to stand with the test plate for one day at each temperature. The tapes were then bonded to a SUS plate (width 50 mm, length 125 mm) via the adhesive layer to create the measurement samples. Bonding to the SUS plate was performed by using a 2 kg roller at a speed of 10 ± 0.5 mm / s for two back-and-forth passes. The adhesive strength was measured using these measurement samples. 2.Measurement method To measure the adhesive strength, a peel test was performed using the measurement sample obtained by the procedure described in 1. above, one hour after the measurement sample was prepared, as follows. Each measurement sample was fixed to the chuck of a tensile testing machine (Tensilon Universal Material Testing Machine, manufactured by A&D Co., Ltd.). Then, under conditions of 23°C and 50RH, the adhesive tape was pulled for more than 60mm at a peel angle of 90° and a speed of 300mm / min, and the interval average value of the load (N) detected by the load cell was recorded and defined as the adhesive strength. Furthermore, the adhesive strengths at 0°C and 40°C were measured using the same method as described above, except that the temperature was set to 0°C or 40°C from sample preparation to measurement.

[0053] <Acid resistance> As shown in Figure 4, dust was removed from the surface (one side and all four sides) of a mortar board 30 measuring 70 mm in length, 150 mm in width, and 20 mm in height, in accordance with JIS R 5201, using commercially available masking tape. As a standard, stretched polypropylene tape with a total light transmittance of 86% or more was applied to the surface, and the surface was cleaned until the total light transmittance of the stretched polypropylene tape after removal was 86% or more. The adhesive tape 10 obtained in each example was applied to the cleaned mortar board, overlapping it to prevent penetration through gaps, and this was used as a sample for evaluating acid resistance. The samples obtained using the above procedure were immersed in sulfuric acid, and their acid resistance was evaluated based on the samples after immersion. When immersing the mortar board in sulfuric acid, in order to ensure that the lower part of the mortar board was also sufficiently exposed to the sulfuric acid, as shown in Figure 5, stainless steel feet 31 with a height of 5 mm or more were placed inside the container, and the sample was placed inside the container with the sheet surface facing downwards on top of the feet 31. Then, a sulfuric acid aqueous solution 32 adjusted to 5 g / L was poured so that the lower surface (bottom) of the mortar was submerged to a depth of 5 to 10 mm. As described above, after immersing the samples for one week, the samples were removed, the immersed portions were washed with running water, and the appearance was evaluated after drying for three days at 23°C and 50RH. During the immersion period, sulfuric acid was added to the container as needed to ensure that the sulfuric acid level did not fall below 5 mm from the bottom of the mortar board due to the evaporation of sulfuric acid. Furthermore, for the samples after immersion, we evaluated whether there were any abnormalities by checking the degree of swelling, cracking, and lifting of the adhesive tape on the surface from the mortar board. In addition, regarding the appearance of the mortar, we evaluated whether there were any abnormalities by checking whether it had whitened compared to the initial state (before immersion in sulfuric acid) due to the reaction with sulfuric acid. However, the underside of the mortar board was used as the evaluation surface, and the 10 mm from all four edges of the evaluation surface, which is the part that comes into contact with the foot, was excluded from the evaluation, and only the inner 130 mm x 50 mm portion was evaluated. The appearance and acid resistance of the mortar were evaluated according to the following evaluation criteria. No abnormalities found in adhesive tape and mortar: ○ rating Abnormalities found in at least one of the adhesive tape and / or mortar: × Rating <Alkali resistance> For a mortar board 30 measuring 70 mm in length, 150 mm in width, and 20 mm in height, conforming to JIS R 5201, dust was removed from the surface (one side and all four sides) using commercially available masking tape. As a standard, stretched polypropylene tape with a total light transmittance of 86% or more was applied to the surface, and the surface was cleaned until the total light transmittance of the stretched polypropylene tape after removal was 86% or more. The adhesive tapes obtained in each example were applied to the cleaned mortar board, overlapping them to prevent penetration through gaps, and these were used as samples for evaluating alkali resistance. Note that the alkali resistance evaluation samples obtained were obtained separately from the acid resistance evaluation samples mentioned above. The samples obtained using the above procedure were immersed in a saturated calcium hydroxide solution, and their alkali resistance was evaluated based on the samples after immersion. When immersing the mortar board in a saturated calcium hydroxide solution, stainless steel feet at least 5 mm high were placed inside the container, and the sample was placed inside the container with the sheet surface facing downwards, resting on the feet. Then, the saturated calcium hydroxide solution was poured so that 15 mm of the lower surface (bottom) of the mortar board was submerged. As described above, after immersing the samples for one week, the samples were removed, the immersed portions were washed with running water, and the appearance was evaluated after drying for three days at 23°C and 50RH. During the immersion period, calcium hydroxide solution was added to the container as needed to ensure that the liquid level of the calcium hydroxide solution did not fall below 15 mm from the bottom of the mortar board due to evaporation. Furthermore, the samples after immersion were examined for swelling, cracking, and lifting of the adhesive tape from the mortar board to assess whether any abnormalities were present. The appearance and alkali resistance of the mortar were evaluated according to the following evaluation criteria. No abnormalities with the adhesive tape: ○ rating Adhesive tape has defects: × rating

[0054] [Materials used] The following materials were used in each example and comparative example.

[0055] <Adhesive layer> • 2-Ethylhexylacrylate n-butyl acrylate Acrylic acid • ACMO (4-acryloylmorpholine) • DMAA (N,N-dimethylacrylamide) • Olefin polymer: Product name "L-1253", manufactured by Kuraray Co., Ltd., hydrogenated polybutadiene having a (meth)acryloyl group at one end. • Tackifying resin 1: Product name "Alcon P140", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 140℃ • Tackifying resin 2: Product name "Alcon P100", manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point 100℃ • Microparticles: Product name "Cellstar Z-27", manufactured by Tokai Kogyo Co., Ltd., glass balloon • Crosslinking agent (1): Product name "TEAI-1000", manufactured by Nippon Soda Co., Ltd. • Crosslinking agent (2): Product name "NK Ester A-HD-N", manufactured by Shin Nakamura Chemical Industry Co., Ltd. • Photopolymerization initiator: 2,2-dimethoxy-2-phenylacetophenone

[0056] <film> • Soft acrylic sheet: Product name "Soft Acrylic Sheet", manufactured by Tatsuta Chemical Co., Ltd. • PET: Product name "Lumirror S10", manufactured by Toray Industries, Inc. • Fluorine-based: Product name "50NS", manufactured by AGC Inc. • Polyvinyl chloride: Product name: "HP 080040M", Nippon Carbide Industries Co., Ltd.

[0057] [Example 1] An adhesive composition was prepared according to the formulations shown in Table 1. Dissolved oxygen was removed from this adhesive composition by purging it with nitrogen. Next, a spacer with the same thickness as the adhesive layer was placed on the release surface of the release sheet, and the adhesive composition was applied to the release surface of the release sheet. Then, another release sheet was covered over the applied adhesive composition so that the release surface was in contact with the adhesive composition. A silicone-release treated PET film (thickness 50 μm) was used as the release sheet. In this state, the UV irradiation intensity on the release sheet on the covering side is 5 mW / cm². 2 The lamp intensity of the chemical lamp was adjusted accordingly, and ultraviolet light was irradiated from one side for 15 minutes to obtain an adhesive layer consisting of an adhesive layer alone with release sheets attached to both sides. Then, after peeling off one of the release sheets, the film (substrate) described in Table 1 was bonded to the adhesive layer obtained by the above method to obtain an adhesive tape. Before performing various physical properties or evaluations on the adhesive tape, the other release sheet was also peeled off. Using the adhesive tape obtained as described above, we performed evaluations of various physical properties.

[0058] [Examples 2-11] The same procedure as in Example 1 was followed, except that the thickness of the adhesive layer, the formulation of the adhesive composition, and the substrate film were changed as shown in Tables 1 and 2.

[0059] [Comparative Example 1] The mortar board was immersed in sulfuric acid without any adhesive tape being applied.

[0060] [Table 1]

[0061] [Table 2] *In the table, "part" refers to the part by mass.

[0062] As is clear from the above examples, the adhesive tape of the present invention has excellent acid and alkali resistance, so that the mortar board to which the tape is attached can maintain a good appearance even after being immersed in sulfuric acid and calcium hydroxide. In contrast, in the comparative example, when the mortar board was immersed in sulfuric acid without adhesive tape being attached to it, the appearance of the mortar board could not be maintained in good condition. Furthermore, the adhesive tape used in the example was applied to the receiving frame, the foundation adjustment section (mortar), and the lower manhole, and the work was carried out without any problems. [Explanation of Symbols]

[0063] 10 Adhesive Tapes 11 Adhesive layer 11A Surface of the adhesive layer 12 Base material 20 slots 21 Fastening bolts 22 Fastening nuts 23 Frame Holder 23A Upper Holder 23B Lower holder 24 Holder Sleeves 25 Bolt Sleeves 26 Mortar 27 Shimomasu 28 Manhole cover 30 Mortar boards 31 Feet for supporting mortar boards 32 Sulfuric acid

Claims

1. An adhesive tape comprising a base material and an adhesive layer provided on at least one side of the base material, The aforementioned adhesive tape is used for protecting the foundation adjustment section of a manhole.

2. The adhesive tape according to claim 1, wherein the adhesive strength of the adhesive tape at 23°C is 10 N / 25 mm or more.

3. The adhesive tape according to claim 1 or 2, wherein the total light transmittance of the adhesive tape is 50% or more.

4. The adhesive tape according to claim 1 or 2, wherein the adhesive layer is formed of an acrylic adhesive.

5. The adhesive tape according to claim 1 or 2, wherein the adhesive layer is formed of a photocurable resin.

6. The adhesive tape according to claim 1 or 2, wherein the thickness of the adhesive layer is 50 to 2500 μm.

7. The adhesive tape according to claim 1 or 2, wherein the storage modulus of the adhesive layer at 23°C is 50,000 to 1,000,000 Pa.

8. The adhesive tape according to claim 1 or 2, wherein the base material comprises a fluororesin, a polyvinyl chloride resin, or an acrylic resin.

9. The adhesive tape according to claim 1 or 2, wherein the thickness of the substrate is 20 to 300 μm.

10. The adhesive tape according to claim 1 or 2, wherein the adhesive tape is used for applications in which it is applied to the foundation adjustment section and to at least one of the receiving frame and the lower manhole.

11. An adhesive tape comprising a base material and an adhesive layer provided on at least one side of the base material, wherein the adhesive tape is used in applications where it is adhered to a mortar surface, and at least one of a metal surface and a concrete surface.

12. A manhole structure comprising the adhesive tape described in claim 1 or 2 and a manhole foundation adjustment section, wherein the adhesive tape covers at least the manhole foundation adjustment section.

13. A method for protecting the foundation adjustment portion of a manhole, comprising applying an adhesive tape, which comprises a base material and an adhesive layer provided on at least one side of the base material, to at least the foundation adjustment portion of the manhole for protection.

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