JP2019172821A - Adhesive tape - Google Patents

Abstract

To provide a novel adhesive tape that has a high flame resistance.SOLUTION: The adhesive tape 1 comprises a base film 2 and an adhesive layer 3, the base film 2 contains a polyolefin resin and a flame retardant and has a plurality of grooves 2c along the side along the longitudinal direction of a face 2a, the adhesive layer 3 contains a cross-link type adhesive and the gelation fraction of the adhesive is in the range of 35 mass% to 100 mass%, and the ratio t/tof the thickness tof the base film 2 to the thickness tof the adhesive layer 3 is in the range of 4.3 to 50.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive tape.

  Conventionally, a flame-retardant pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer containing a flame retardant has been known (for example, Patent Documents 1 and 2).

JP 2002-69400 A (published March 8, 2002) JP 2013-112788 A (released on June 10, 2013)

  In recent years, further improvement in the flame retardancy of adhesive tapes has been demanded.

  This invention is made | formed in view of the said subject, The objective is to provide the novel adhesive tape provided with high flame retardance.

  In order to solve the above problems, an adhesive tape according to one embodiment of the present invention includes a base material layer and an adhesive layer, and the base material layer includes a polyolefin resin and a flame retardant, and includes at least one of them. The adhesive layer has a plurality of recesses along one direction of the surface, the adhesive layer contains a cross-linkable adhesive, and the gelation fraction of the adhesive layer is in the range of 35% by mass to 100% by mass, The ratio of the thickness of the base material layer to the thickness of the adhesive layer is in the range of 4.3 to 50.

  According to one embodiment of the present invention, an adhesive tape having high flame retardancy can be provided.

It is a perspective view explaining the outline of adhesive tape 1 concerning one mode of the present invention. It is a perspective view explaining the outline of the base film 2 with which the adhesive tape 1 which concerns on 1 aspect of this invention is provided.

<Adhesive tape>
As shown in FIGS. 1 and 2, an adhesive tape 1 according to one embodiment of the present invention includes a base film 2 and an adhesive layer 3.

  The pressure-sensitive adhesive tape according to one embodiment of the present invention uses a polyolefin resin film having a recess as a base film, and can be easily cut in the width direction without using a cutting tool such as a scissors. Excellent workability in work. Furthermore, since the pressure-sensitive adhesive tape according to one embodiment of the present invention includes only two layers, it can be manufactured at low cost.

[Base film (base layer)]
A base film (base material layer) 2 shown in FIG. 1 is a film molded from a resin composition containing a polyolefin resin and a flame retardant.

(Polyolefin resin)
The base material film which is a base material layer is a film obtained by shape | molding polyolefin resin, and can mention well-known polyolefin resin as an olefin resin. Examples of the polyolefin resin include a homopolymer or copolymer of an olefin monomer, or a copolymer of an olefin monomer and another monomer. Examples of the olefin monomer include ethylene, propylene, and α-olefin monomers other than propylene. Hereinafter, in the present specification, α-olefin means an α-olefin monomer other than propylene. Examples of the α-olefin monomer include butene-1, pentene-1, hexene-1, heptene-1, octene-1, nonene-1, 4-methylpentene-1, and decene-1. . The olefin resin may contain two or more olefin monomers as structural units.

  Examples of the other monomer other than the olefin monomer include vinyl ester monomers such as vinyl acetate, and acrylate monomer such as methyl acrylate. it can. In addition, the various acrylic acid ester described in this specification can be replaced with the methacrylic acid ester provided with the same functional group.

  More specifically, the olefin resin includes polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-α-olefin copolymer, propylene-α-olefin copolymer, ethylene-propylene-α-olefin copolymer. , Ethylene-vinyl acetate polymer, ethylene-methyl acrylate copolymer, etc., where polyethylene includes high density polyethylene (HDPE) and low density polyethylene (LDPE).

  The melt flow rate (hereinafter referred to as MFR) of the polyolefin resin constituting the base film is in the range of 5 g / 10 min or more and 20 g / 10 min or less. If the MFR of the polyolefin resin is 5 g / 10 min or more, it can be cut successfully by human hands, in other words, the base film 2 having high hand cutting properties can be obtained, and as a result, the hand of the adhesive tape 1 Cutting performance can be improved. Moreover, if MFR of polyolefin resin is 20 g / 10min or less, it can prevent by the intensity | strength of polyolefin resin itself that the intensity | strength with respect to the stress added along the process direction of the adhesive tape 1 falls excessively. This is also advantageous from the viewpoint that when the base film is molded, the base film can be sufficiently tensioned and a base film having a uniform film thickness can be produced. .

  When the resin composition for molding the base film contains two or more polyolefin resins, the melt flow rate (MFR) value of the polyolefin resin obtained by melt-kneading two or more polyolefin resins is 5 g. / 10 minutes or more and 20 g / 10 minutes or less. In one aspect, the polyolefin resin is obtained by melting and kneading high-density polyethylene and low-density polyethylene from the viewpoint that both high mechanical strength and high hand cutting properties can be imparted to the base film 2 in a balanced manner. It is preferable that the polyolefin resin component has an MFR in the range of 5 g / 10 min or more and 20 g / 10 min or less. The polyolefin resin may have a ratio of high density polyethylene to low density polyethylene in the range of 1/4 to 4/1. The melt flow rate of the polyolefin resin is measured under the conditions of a temperature of 190 ° C. and a load of 21.18N.

(Flame retardants)
The flame retardant is an additive for imparting flame retardancy to the pressure-sensitive adhesive tape 1, and a known flame retardant can be used.

  The flame retardant is typically but not limited to melamine cyanurate. Melamine cyanurate is a preferable flame retardant because it can impart high flame retardancy to the adhesive tape and can be suitably dispersed in the polyolefin resin, and in particular, when the adhesive tape after use is burned and disposed of, For example, it is a more preferable flame retardant because it does not generate corrosive gas due to halogen and does not leave fuel ash. For this reason, the adhesive tape which concerns on 1 aspect of this invention can be used for the periodic repair etc. in a nuclear facility by utilizing a flame retardance and workability | operativity by using a melamine cyanurate as a flame retardant. It can be suitably used as a flame retardant curing material.

The content of melamine cyanurate contained in the base film is within the range of 20% by mass or more and 70% by mass or less, assuming that the total of the polyolefin resin and melamine cyanurate constituting the base film is 100. Is preferred. When the blending amount of melamine cyanurate is 20% by mass or more, the flame retardancy of the adhesive tape can be suitably increased,
If the blending amount of melamine cyanurate is 70% by mass or less, the tension of the molten film of the resin composition containing the flame retardant is lowered when the base film is molded from the olefin resin containing melamine cyanurate. This can be prevented, whereby the base film can be suitably formed.

  In addition, as a flame retardant other than melamine cyanurate, flame retardancy can be imparted, and the type thereof is not limited as long as it can be suitably dispersed in a polyolefin resin. For example, melamine, urea, urea compound, guanidine, And nitrogen-containing compounds such as guanidine compounds, and inorganic flame retardants such as antimony trioxide, antimony pentoxide, zinc sulfide, and zinc borate, and hexabromobenzene, bis (dibromopropyl) tetrabromobisphenol A, Examples thereof include halogen-based flame retardants such as bis (dibromopropyl isocyanurate), tris (tribromoneopentyl) phosphate, and decabromodiphenyl oxide, and phosphate ester-based flame retardants. In addition, also when using flame retardants other than melamine cyanurate, the compounding quantity is based on content of melamine cyanurate.

  In addition, the base film is selected from additives such as antioxidants, dispersants, fillers, colorants such as pigments and dyes, lubricants, and antistatic agents, as long as the effects of the present invention are not significantly impaired. At least one additive may be appropriately blended. The content of these additives in the base film is not particularly limited as long as the content is within the range not impairing the effect of the present invention.

(Adhesive layer)
The pressure-sensitive adhesive layer is a layer formed from a pressure-sensitive adhesive for attaching a pressure-sensitive adhesive tape to an adherend (not shown), and includes a cross-linking pressure-sensitive adhesive. The pressure-sensitive adhesive layer provided in the pressure-sensitive adhesive tape according to one aspect has a gelation fraction in the range of 35% by mass to 100% by mass, preferably in the range of 40% by mass to 98% by mass, More preferably, it is in the range of 45 mass% or more and 96 mass% or less. When the gel fraction of the adhesive layer is 35% by mass or more, it is preferable that the adhesive layer softens and flows when exposed to a high temperature, thereby reducing the flame retardancy of the adhesive tape. Can be prevented. Moreover, the said adhesion layer can maintain suitably the adhesiveness to a to-be-adhered body because a gelling fraction is 100 mass% or less.

The gelation fraction can be determined as the ratio of the insoluble component (gelled product) in the adhesive layer of the adhesive tape. More specifically, a pressure-sensitive adhesive tape whose mass has been measured in advance is wrapped with a SUS wire mesh, and immersed in a room temperature organic solvent for about 2 hours, so that soluble components contained in the pressure-sensitive adhesive layer are extracted from the pressure-sensitive adhesive tape. Next, the pressure-sensitive adhesive tape immersed in the organic solvent is dried, and the mass of the pressure-sensitive adhesive tape from which the soluble component contained in the pressure-sensitive adhesive layer is extracted is measured. Then, the mass of the base film peeled from the adhesive tape is measured. Thus, from the mass corresponding to the following X, Y, and Z, the gelation fraction of the adhesion layer is measured based on the following formula (1). In addition, it cannot be overemphasized that the flame retardant is contained in the base film in an adhesive tape.
Gelation fraction (% by mass) = [(Y−Z) / (X−Z)] × 100 (1)
In formula (1), X, Y, and Z are as shown below.
X: Weight of adhesive tape consisting of base film and adhesive layer before immersion treatment Y: Weight of adhesive tape consisting of base layer remaining in wire mesh after immersion and insoluble adhesive layer component Z: After immersion treatment The weight of the base film from which the adhesive component has been removed

  In the Examples, the method for measuring the gelation fraction in the acrylic pressure-sensitive adhesive is described in detail, so please refer to it. However, the evaluation method used in Examples and Comparative Examples is an example of a method for measuring the gelation fraction in the acrylic pressure-sensitive adhesive, and the gelation fraction of the adhesive layer is a known gelation fraction measurement. You may measure by the method.

(Acrylic adhesive)
The pressure-sensitive adhesive layer is not limited, but can typically be a layer formed from an acrylic pressure-sensitive adhesive that is a cross-linkable pressure-sensitive adhesive. It is more preferable to use an acrylic pressure-sensitive adhesive from the viewpoint that high pressure-sensitive adhesiveness can be imparted to the pressure-sensitive adhesive layer, and that a pressure-sensitive adhesive tape with low ash content after incineration can be formed.

  Acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing as a main component an acrylate copolymer obtained by copolymerization of various acrylate monomers and copolymerizable monomers as required, and contains a crosslinking agent. It is a pressure-sensitive adhesive that can be gelled.

  Examples of the acrylate monomer include, for example, methyl acrylate, ethyl butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, benzyl acrylate, alkyl acrylate, butyl methacrylate, methacryl Methacrylic acid alkyl esters such as 2-ethylhexyl acid, cyclohexyl methacrylate, and benzyl methacrylate are used, and these acrylate monomers are used alone or in combination of two or more.

  As the copolymerizable monomer copolymerized with the acrylate monomer, a monomer having a functional group is preferably used. For example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, N-methylol acrylamide, allyl Hydroxyl group-containing monomers such as alcohol; tertiary amino group-containing monomers such as dimethylaminopropyl acrylate; N-substituted amide group-containing monomers such as acrylamide, N-methylacrylamide, N-methoxymethylacrylamide, N-octylacrylamide; glycidyl methacrylate And the like, and the like. Moreover, the monomer which does not have a functional group can also be copolymerized suitably, and a vinyl acetate, vinyl propionate, vinyl ether, styrene, acrylonitrile etc. are mentioned as a monomer which does not have these functional groups, for example.

  Commercially available products of the above acrylic copolymers include Nisset (registered trademark) (manufactured by Nippon Carbide Industries Co., Ltd.), Olivevine (registered trademark) (manufactured by Toyochem Co., Ltd.), Aron Tac (registered trademark) (manufactured by Toagosei Co., Ltd.). , Cybinol (registered trademark) (manufactured by Seiden Chemical Co., Ltd.), SK Dyne (registered trademark) (manufactured by Soken Chemical Co., Ltd.), Acryset (registered trademark) (manufactured by Nippon Shokubai Co., Ltd.), Vinzole (registered trademark) (one company) And fats and oils industry), vinylol (registered trademark) (made by Showa Denko KK), Coponil (registered trademark) (made by Nippon Synthetic Chemical Industry Co., Ltd.), and the like.

  In addition, examples of the pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive layer include vinyl ether-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and rubber-based pressure-sensitive adhesives, and resins included in these pressure-sensitive adhesives. Examples thereof include those into which a functional group such as a hydroxyl group, a carboxyl group, a hydroxyalkyl group, an amino group, or an epoxy has been introduced. By reacting the functional group contained in these pressure-sensitive adhesives with a crosslinking agent, the gel fraction may be adjusted to form a pressure-sensitive adhesive layer.

  In these pressure-sensitive adhesives, in addition to the crosslinking agent described later, tackifiers, softeners, plasticizers, anti-aging agents, stabilizers, antioxidants, dispersants, fillers, wetting agents, viscosity modifiers, pigments, It may also contain at least one additive selected from colorants such as dyes, lubricants, antistatic agents, and additives such as solvents. The content of these additives in the pressure-sensitive adhesive layer is not particularly limited as long as the content is within the range not impairing the effect of the present invention.

  The adhesive resin used when the adhesive layer is formed by laminating an adhesive resin on the base film by extrusion lamination is not particularly limited, and a known adhesive resin can be used. Examples of adhesive resins include copolymer elastomers of ethylene and propylene, or α-olefins such as butene, copolymer elastomers of propylene and butene, ethylene-vinyl acetate copolymers, and ethylene-acrylic ester copolymers. And the like, a block copolymer of styrene and olefin, and a hydrogenated product thereof.

(Crosslinking agent)
Examples of the crosslinking agent that can be reacted with the crosslinkable functional group copolymerized in the acrylic ester copolymer include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, and amines. A crosslinking agent, an amino resin type crosslinking agent, etc. can be mentioned.

  Examples of the isocyanate-based crosslinking agent include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2 , 4'-diphenylmethane diisocyanate, 3-methyldiphenylmethane diisocyanate and other aromatic isocyanates, and hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis (cyclohexyl isocyanate) ), 2,4′-methylenebis (cyclohexyl isocyanate), diisocyanate compounds such as aliphatic isocyanates such as lysine isocyanate, and these diisocyanates. Modified products of sulfonate compounds. Here, the modified form of the diisocyanate compound includes a trimethylolpropane adduct-type modified body, a burette-type modified body reacted with water, and an isocyanurate-type modified body containing an isocyanurate ring.

  Epoxy crosslinking agents include, for example, diglycidyl ether of bisphenol A and oligomers thereof, diglycidyl ether of hydrogenated bisphenol A and oligomers thereof, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p -Oxybenzoic acid glycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, ethylene glycol diglycidyl ether, propylene glycol di- Glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol Cole diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolpropane di or triglycidyl ether, pentaerythritol di or Examples thereof include triglycidyl ether, triglycidyl ether of glycerol alkylene oxide adduct, and diglycidyl amine such as diglycidyl aniline.

  Although it does not specifically limit as an aziridine type crosslinking agent, As the specific example, 1,1'- (methylene-di-p-phenylene) bis-3,3- aziridinyl urea, 1,1'- (hexamethylene) bis -3,3-aziridinyl urea, 2,4,6-triaziridinyl-1,3,5-triazine, trimethylolpropane-tris- (2-aziridinylpropionate) and the like.

  Examples of the metal chelate-based crosslinking agent include compounds in which acetylacetone, ethyl acetoacetate, and the like are coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. Etc.

  Examples of amine-based crosslinking agents include polyamines such as aliphatic polyamines (for example, triethylenetetramine, tetraethylenepentamine, ethylenediamine, N, N-dicinnamylidene-1,6-hexanediamine, trimethylenediamine, hexamethylenediamine carbamate, ethanolamine. 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxa-2-spiro [5.5] undecane and the like) and salts thereof; aromatic polyamines (for example, diaminodiphenylmethane, xylylenediamine) , Phenylenediamine, diaminodiphenylsulfone and the like.

  Examples of amino resin-based crosslinking agents include methoxylated methylol urea, methoxylated methylol N, N-ethyleneurea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine, and the like. Preferably, methoxylated methylol melamine, butoxylated methylol melamine, methylolated benzoguanamine and the like can be mentioned.

  Among these, from the viewpoint of obtaining high adhesive force even when the pressure-sensitive adhesive layer is thinned, an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent is preferable. In addition, you may use said crosslinking agent individually or in combination of 2 or more types.

  The content of the cross-linking agent is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the adhesive containing the acrylic ester copolymer from the viewpoint of obtaining high adhesive strength even if the adhesive layer is thinned. Preferably it is 0.05-8 mass parts, More preferably, it is 0.1-6 mass parts.

  In addition, since the flame retardant performance of the pressure-sensitive adhesive tape is further enhanced, the pressure-sensitive adhesive layer may contain a flame retardant to the extent that the adhesiveness is not impaired.

  The flame retardant compounded in the adhesive layer should contain melamine cyanurate, for example, because it does not generate corrosive gas caused by halogen and does not leave fuel ash when burning the adhesive tape after use. preferable.

(Shape of adhesive tape: ratio of thickness of base film and adhesive layer)
As shown in FIG. 1, the pressure-sensitive adhesive in tape 1, the thickness _{t 1} of the substrate film 2, the ratio between the thickness _{t 2} of the adhesive layer 3 _(t 1 / _{t 2)} is in the range of 4.3 to 50. More preferably, it is in the range of 4.4 to 50. Adhesive tape 1 has a thickness _{t 1} of the substrate film 2, the ratio between the thickness _{t 2} of the adhesive layer 3 _(t 1 / _{t 2)} is in the range of 4.3 to 50., wherein the adhesive When the gelling fraction of the layer 3 is in the range of 35% by mass or more and 100% by mass or less, the adhesive layer softens and flows when the adhesive layer is exposed to a high temperature as described above. In addition to being able to suitably prevent the flame retardancy of the pressure-sensitive adhesive tape from being lowered, the oxygen index (%) is as high as 26 or higher without the addition of a flame retardant in the pressure-sensitive adhesive layer. Flame retardancy can be achieved. The oxygen index may be measured according to JIS K7201.

  Although the adhesive tape which concerns on one aspect is an adhesive tape which consists of two layers of a base film and an adhesive layer, it has high flame retardance and is an adhesive tape which an operator can cut | disconnect successfully by hand. is there.

The thickness t ₁ of the base film 2 is defined as the thickness between the surface (first surface) 2a of the recess is provided side surface on the side facing away from the surface 2a (the second surface) 2b Is done. Moreover, the thickness of the adhesion layer 3 is prescribed | regulated as thickness between the surface (1st surface) 3a facing 2a of the base film 2, and the surface (2nd surface) 3b for affixing on a to-be-adhered body. The The thickness _{t 2} of the adhesive layer is 10 m to 60 m, more preferably 10Myuemu～40myuemu.

  As shown in FIG. 1, the base film 2 is in each of two sides facing each other along the longitudinal direction (x direction, also referred to as MD) in one surface (first surface) 2 a of the base film 2. A plurality of recesses are provided along these sides. A recessed part is a recessed part formed as a hollow which divides each of these two sides into a plurality. When it is assumed that the recess has a side having the same length as the width w of the recess separating each of the two sides, the depth d along the thickness direction of the base film 2 is set with the side of the width w as the base. It is shaped like an inverted triangle with a height. A plurality of recesses are provided for each interval l on each of two sides along the longitudinal direction (one direction) of the base film 2. Thereby, the operator who uses the adhesive tape 1 can cut the adhesive tape 1 successfully. Moreover, the recessed part provided in the base film 2 in the adhesive tape 1 which concerns on one aspect is a groove-shaped recessed part along the width direction (y direction, TD) of the surface 2a, and the surface 2a is made into several surface. It is molded as a groove 2c that is divided into two (FIG. 2). Thereby, the operator who uses the adhesive tape 1 can cut the adhesive tape straight and successfully in the width direction perpendicular to the longitudinal direction of the adhesive tape 1. In addition, the shape of the concave portion seen from the side, that is, horizontal to one surface of the adhesive tape 1 and seen from the line of sight along the width direction is assumed to have a side with a width w along the longitudinal direction. For example, a rectangular shape having one side of the width w as a side and a semicircular shape having a side having the width w as a radius may be used. An inverted isosceles triangle is preferable.

  The width w of the groove 2c is 0.01 to 0.7 mm, preferably 0.02 to 0.5 mm, and more preferably 0.01 to 0.3 mm. When the width w of the groove 2c is 0.01 mm or more, when the groove 2c of the base film 2 is formed by a roll (not shown), the width from the roll is reduced due to the narrow width of the groove 2c. It can prevent that the mold release property of the base film 2 falls. Moreover, when the width w of the groove 2c is narrower than 0.7 mm, the stress concentration on the deepest part of the groove 2c tends to be improved.

  The depth d of the groove 2c is 0.03 to 0.3 mm, preferably 0.03 to 0.12 mm. If the depth d of the groove 2c is 0.03 mm or more, an operator who uses the adhesive tape 1 can successfully cut the adhesive tape 1 along the width direction by hand. If it is 0.3 mm or less, the mechanical strength in the longitudinal direction of the pressure-sensitive adhesive tape 1 can be suitably maintained.

  The interval 1 between the groove portions 2c is 0.5 to 5 mm, preferably 0.6 to 1.4 mm. If the distance l is 0.5 mm or more, high hand cutting properties can be imparted to the adhesive tape 1, and if it is 5 mm or less, the mechanical strength in the longitudinal direction of the adhesive tape 1 can be suitably maintained. , Can be cut successfully at the location intended by the operator. Here, the interval 1 between the groove portions 2c is defined on the basis of the apex in the triangular shape which is the deepest portion of the groove portion 2c.

In the pressure-sensitive adhesive tape 1 according to one aspect, the difference between the thickness t ₁ of the base film 2 and the depth d of the groove 2 c is 10 to 90 μm. Thereby, irrespective of the thickness of the base film 2, it becomes an adhesive film in which the tensile strength and tear strength in the longitudinal direction and the hand cutting property in the width direction are balanced. Since the difference between the thickness t ₁ of the base film 2 and the depth d of the groove 2c is 10 to 90 μm, it is possible to suitably maintain hand cutting along the width direction. A suitable strength can be achieved while designing the type of polyolefin resin constituting the base film and the thickness of the base film so that the required strength in the longitudinal direction is expressed.

  Further, an extremely fine uneven pattern (not shown) having a mesh shape of about 60 to 250 mesh may be further formed on the surface 2 a of the base film 2. By forming an extremely minute uneven pattern on the surface 2 a of the base film 2, the adhesion between the adhesive layer 3 and the base film 2 can be enhanced. The extremely minute uneven pattern may be formed only on the surface 2a of the base film 2 or may be formed on the entire surface including the inside of the groove 2c.

(Adhesive tape shape: reinforced bridge in base film)
As shown in FIG. 2, the groove 2c of the base film 2 is provided with a reinforcing bridge 2d for compensating the strength to the extent that the adhesive tape is not damaged by hand on the inner side along the longitudinal direction. Good. By providing the reinforcing bridge 2d, the strength against the stress applied so as to be pulled along the longitudinal direction can be supplemented. In addition, although the reinforcement bridge 2d shown in FIG. 2 is provided in three places inside the groove part 2c, if the reinforcement bridge provided in one groove part can supplement the intensity | strength of the base film 2, the number will be limited. Not.

  The surface substantially parallel to the surface 2a of the reinforcing bridge 2d may be flush with the surface 2a of the base film 2, but is preferably a base for making the adhesive tape 1 easy to cut straight along the width direction. It is preferable that it exists in the position lower than the surface 2a of a material film.

(Manufacturing method of adhesive tape)
Although it will not be limited if the base film 2 can provide a recessed part in at least one surface, Typically, it is an unstretched film obtained without extending | stretching at the time of manufacture. Since the base film 2 is an unstretched film, it has high hand cutting properties. The unstretched film means a film manufactured without going through an intentional stretching process, and is stretched slightly by the extension of the film extrusion direction, which occurs during the general film manufacturing take-up, so-called pull-down, etc. It may be.

  The method for forming the groove 2c on the surface 2a of the base film 2 is not particularly limited. For example, a previously manufactured film having smooth both surfaces is heated and passed between the squeeze rolls to form grooves or microscopic features. A method of forming a concavo-convex pattern, or after extruding a molten resin from an extruder through a T-shaped die into a film shape, this is passed between a squeeze roll and a rubber roll with a smooth surface, whereby the film is made into a squeeze roll with a rubber roll There is a method of forming by pressing and transferring the surface shape of the squeezing roll onto a film. There is no particular limitation on the method for forming an extremely fine uneven pattern on the uneven surface of the base film, and the same method as that for forming grooves can be applied.

  As a method for producing a substrate film having a reinforcing bridge, for example, there is a method of transferring to a film using a roll having a shape imprinted on the surface so that a groove shape having a reinforcing bridge can be transferred.

  The method of providing the adhesive layer 3 on the base film 2 is not particularly limited, and examples thereof include a method of applying an adhesive to the surface 2 a of the base film 2. The coating method is not particularly limited, and examples of the coating method include a comma coater method, a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method. Known methods such as Needless to say, the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer 3 is mixed with a crosslinking agent in advance. Moreover, after apply | coating an adhesive to the base film 2, it is good to dry an adhesive and to form the adhesion layer 3. FIG. Other methods include laminating an adhesive resin on one side of the base film by an extrusion lamination method.

  In order to improve the adhesion between the pressure-sensitive adhesive layer 3 and the base film 1 or the wettability of the pressure-sensitive adhesive to the base film 2, the surface of the base film 2 on which the pressure-sensitive adhesive layer 3 is provided is subjected to corona discharge or the like. It is preferable to perform processing.

  In addition, from the viewpoint of optimizing the feeding workability of the pressure-sensitive adhesive tape 1, a release agent (release agent) may be applied to the surface 2b of the base film 2 on which the pressure-sensitive adhesive layer 3 is not laminated. preferable. In this case, it is preferable to perform surface treatment on both surfaces of the base film 2.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited the range by these Examples.

[Density (Unit: kg / m ³ )]
The density was measured at 23 ° C. according to A method (underwater substitution method) in JISK7112-1980. In addition, the sample which measures a density was annealed according to the method prescribed | regulated to JISK6760-1995 previously.

[Melt flow rate (MFR) (unit: g / 10 min)]
The melt flow rate was measured under the conditions of a load of 2.16 kg and a temperature of 190 ° C. according to the method defined in JIS K7210-1995.

[Uneven shape (unit: mm)]
Using a stylus type surface roughness measuring machine (Surf Test, manufactured by Mitutoyo Corporation), the concavo-convex surface side of the base film is moved in a direction perpendicular to the vertical direction (TD), and the groove width W, groove depth D, and groove interval 1 (el) were measured. Further, the depth of the groove was subtracted from the thickness of the base film to obtain a difference (μm) between the thickness and the groove depth.

[Gel fraction (unit: mass%)]
After measuring the weight: X of the pressure-sensitive adhesive tape comprising the base material layer (base material film) and the pressure-sensitive adhesive layer, the pressure-sensitive adhesive tape was wrapped in a 200-mesh SUS wire mesh and immersed in ethyl acetate at 23 ° C. for 2 hours. . The weight after drying the adhesive tape composed of the base material layer remaining in the wire mesh after immersion and the insoluble adhesive component was measured. Next, the pressure-sensitive adhesive component was removed, and the weight Z of the base material layer was measured. The gelation fraction was determined from the following formula.
Gelation fraction (mass%) = [(YZ) / (XZ)] × 100
In formula (1), X, Y, and Z are as shown below.
X: Weight of pressure-sensitive adhesive tape before dipping treatment Y: After drying a pressure-sensitive adhesive tape comprising a base material layer remaining in the wire mesh after dipping and an insoluble pressure-sensitive adhesive component Z: Weight of pressure-sensitive adhesive tape before dipping treatment, The above method is a method for measuring the acrylic pressure-sensitive adhesive used in the examples and comparative examples of the present application, and may be measured by a known gelation fraction measuring method suitable for the pressure-sensitive adhesive.

[Tear strength (unit: cN)]
The tear strength was measured according to the method defined in JISP8116. A base film was cut in the vertical direction (TD), and a test piece not cut in the test direction was prepared as a test piece, and the tear strength of one test piece was measured using an Elmendorf-type tear tester.

[Oxygen index (unit:%)]
The oxygen index was measured according to the method defined in JISK7201-2.
The shape of the test piece was V-shaped, and the one obtained by cutting 140 mm in the processing direction (MD) of the adhesive tape and 50 mm in the vertical direction (TD) was used.

[Adhesive strength (unit: N / 25 mm)]
The adhesive strength was measured according to the method defined in JISZ0237-2000. The adhesive strength was measured at a test speed of 300 mm / min. A SUS304 steel plate was used as a test plate (adhered body), and the adherend surface of the test plate was water-polished with water-resistant abrasive paper (# 360, manufactured by Riken Corundum Co., Ltd.).

<Example 1>
First, 30% by mass of polyethylene resin A (density: 958 kg / m ³ , MFR: 20.0 g / 10 min) and 70% by mass of polyethylene resin B (density: 922 g / m ³ , MFR: 5.0 g / min) A resin composition (MFR: 7.6 g / 10 min) was prepared by mixing, and the prepared resin composition was 70% by mass, and melamine cyanurate (particle diameter 2 μm) was 30% by mass. And these were heated and kneaded at 180 ° C. with a twin-screw extruder kneader to obtain flame retardant-containing pellets. The pellets were supplied to an extruder and extruded at 160 to 190 ° C.

  Next, as shown in FIG. 1, the molten sheet is cooled and solidified while being pressed with a rubber roll that can form a smooth surface 2 b of the extruded molten sheet and a crest roll having a surface that can form a groove 2 c on the surface 2 a. A base film 2 having a thickness of 100 μm was obtained. The surface 2a of the polyethylene base film 2 obtained above is subjected to a corona discharge treatment so as to have a wetting tension of 45 dyne / cm or more, and a commercially available acrylate copolymer is a main component on the treated surface 2a. A pressure-sensitive adhesive solution in which 6 parts by weight of a crosslinking agent (L-45E manufactured by Soken Chemical Co., Ltd.) is mixed with a 100% acrylic pressure-sensitive adhesive (non-volatile content 44%, viscosity 8.9 Pa · s / 25 ° C.) The pressure-sensitive adhesive layer after drying was applied to a thickness of 20 μm using a coater and dried to form a pressure-sensitive adhesive layer 3 of an acrylic pressure-sensitive adhesive. Table 1 shows the physical properties of the obtained base film 2 and the pressure-sensitive adhesive tape 1.

<Example 2>
Adhesive layer after drying a pressure-sensitive adhesive solution containing 2 parts by weight of a crosslinking agent (E-5CM manufactured by Soken Chemical Co., Ltd.) with respect to 100 parts by mass of the acrylic pressure-sensitive adhesive used in Example 1 using a comma coater A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive layer was formed by applying and drying to a thickness of 20 μm. Table 1 shows the physical properties of the obtained base film and adhesive tape.

<Example 3>
A pressure-sensitive adhesive tape was obtained in the same manner as in Example 2 except that the pressure-sensitive adhesive layer after drying was applied and dried to form an acrylic pressure-sensitive adhesive layer. Table 1 shows the physical properties of the obtained base film and adhesive tape.

<Example 4>
A resin composition in which 30% by mass of polyethylene resin A (density: 958 kg / m3, MFR: 20.0 g / 10 min) and 70% by mass of polyethylene resin C (density: 924 g / m3, MFR: 3.7 g / min) are mixed. Melamine cyanurate was blended into the product (MFR: 6.1 g / 10 min) so that the resin composition was 80% by mass and melamine cyanurate (particle diameter 2 μm) was 20% by mass, and these were biaxially extruded. The mixture was heated and kneaded at 180 ° C. with a kneader to obtain flame retardant-containing pellets. The pellets were supplied to an extruder and extruded at 160 to 190 ° C. The extruded molten sheet is cooled and solidified while being pressed with a rubber roll that can form the surface 2b shown in FIG. A base film 2 having a thickness of 100 μm was obtained. A pressure-sensitive adhesive tape 1 was obtained in the same manner as in Example 3 except for the polyethylene base film obtained above. Table 1 shows the physical properties of the obtained base film 2 and the pressure-sensitive adhesive tape 1.

<Comparative Example 1>
The acrylic pressure-sensitive adhesive solution used in Example 1 was applied with a comma coater so that the thickness of the pressure-sensitive adhesive layer after drying was 20 μm and dried to form an acrylic pressure-sensitive adhesive layer. In the same manner, an adhesive tape was obtained. Table 2 shows the physical properties of the obtained base film and adhesive tape.

<Comparative example 2>
The pressure-sensitive adhesive layer thickness after drying a pressure-sensitive adhesive solution containing 2 parts by weight of a crosslinking agent (L-45E, manufactured by Soken Chemical Co., Ltd.) with respect to the acrylic pressure-sensitive adhesive 100 used in Example 1 is 20 μm. A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive layer was formed by coating and drying. Table 2 shows the physical properties of the obtained base film and adhesive tape.

<Comparative Example 3>
A pressure-sensitive adhesive tape was obtained in the same manner as in Example 2, except that the pressure-sensitive adhesive layer after drying was applied and dried to form an acrylic pressure-sensitive adhesive layer. Table 2 shows the physical properties of the obtained base film and adhesive tape.

<Comparative Example 4>
A base film was obtained in the same manner as in Example 1 except that the thickness was 125 μm. The concavo-convex surface side of the polyethylene base film obtained above was subjected to corona discharge treatment so as to have a wetting tension of 45 dyne / cm or more, and on the treated surface, the acrylic pressure-sensitive adhesive 100 used in Example 1, A pressure-sensitive adhesive solution containing 1 part by weight of a cross-linking agent (E-5CM manufactured by Soken Chemical Co., Ltd.) was applied using a comma coater so that the thickness of the pressure-sensitive adhesive layer after drying was 30 μm, and dried to obtain an acrylic pressure-sensitive adhesive. A layer was formed to obtain an adhesive tape. Table 2 shows the physical properties of the obtained base film and adhesive tape.

The adhesive tape which concerns on 1 aspect of this invention can be utilized suitably as a flame-retardant curing material in the periodic repair etc. in a nuclear power related facility, for example.

1 Adhesive tape 2 Base film (base layer)
2a surface (first surface)
2b surface (second surface)
2c Groove (recess)
2d Reinforcement bridge 3 Adhesive layer t ₁ Substrate film thickness t ₂ Adhesive layer thickness w Width (groove)
d Depth (groove)
l Spacing (groove)

Claims (6)

A base material layer and an adhesive layer;
The base material layer includes a polyolefin resin and a flame retardant, and has a plurality of recesses along a side along one direction of at least one surface,
The pressure-sensitive adhesive layer contains a cross-linkable pressure-sensitive adhesive, and the gelation fraction of the pressure-sensitive adhesive layer is in the range of 35% by mass to 100% by mass,
The adhesive tape whose ratio of the thickness of the base material layer with respect to the thickness of the said adhesive layer exists in the range of 4.3 or more and 50 or less.   The pressure-sensitive adhesive tape according to claim 1, wherein the content of the flame retardant in the base material layer is within a range of 20% by mass or more and 70% by mass or less.   The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the flame retardant is melamine cyanurate.   The polyolefin resin contains high-density polyethylene and low-density polyethylene, and the melt flow rate measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N of the polyolefin resin is 5 g / 10 min or more, 20 g / 10 min. The pressure-sensitive adhesive tape according to any one of claims 1 to 3, which is within the following range.   The pressure-sensitive adhesive tape according to claim 1, wherein the cross-linking pressure-sensitive adhesive contains an acrylic pressure-sensitive adhesive.   The pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein the concave portion is a groove-shaped concave portion along a direction intersecting the one direction, and divides the at least one surface into a plurality of portions.