WO2020189724A1

WO2020189724A1 - Adhesive tape and adhesive tape roll

Info

Publication number: WO2020189724A1
Application number: PCT/JP2020/012022
Authority: WO
Inventors: 大平杉田
Original assignee: 積水化学工業株式会社
Priority date: 2019-03-20
Filing date: 2020-03-18
Publication date: 2020-09-24
Also published as: TW202045661A; KR20210142086A; CN113316623A; JP2020180302A; CN113316623B; JP2020158756A; JP6749464B1

Abstract

The purpose of the present invention is to provide an adhesive tape in which the problem of unwinding from a roll during prolonged storage can be suppressed even when the adhesive tape has a thick adhesive layer, and an adhesive tape roll comprising said adhesive tape. The present invention is a long adhesive tape in which a base material, an adhesive layer, and a release film are layered in this order, wherein the ratio (exudation after 24 hours/exudation after 1 hour) of the amount of exudation of the adhesive layer after 1 hour and the amount of exudation of the adhesive layer after 24 hours when the adhesive tape is sandwiched by two SUS304 sheets and a load of 1 kg is placed thereon at 23°C is 4 or less.

Description

Adhesive tape and adhesive tape roll

The present invention relates to an adhesive tape and an adhesive tape roll composed of the adhesive tape.

Adhesive tapes are used in various industrial fields because they can be easily joined. In the construction field, temporary fixing of curing sheets, bonding of interior materials, etc., in the automobile field, fixing of interior parts such as seats and sensors, fixing of exterior parts such as side moldings and side visors, etc., in the electrical and electronic field, module assembly, Adhesive tape is used to attach the module to the housing. More specifically, for example, an adhesive tape is widely used as a surface protective tape for temporarily protecting the surface of a member such as an optical device, a metal plate, a painted metal plate, a resin plate, or a glass plate (adhesive tape). For example, Patent Documents 1 to 3).

Japanese Unexamined Patent Publication No. 1-129085 Japanese Unexamined Patent Publication No. 6-1958 Japanese Unexamined Patent Publication No. 8-12952

Usually, the adhesive tape is shipped in the form of an adhesive tape roll that is wound into a roll after being manufactured, is appropriately rewound from the adhesive tape roll, and is cut into an appropriate shape and provided. However, the conventional adhesive tape roll may not be able to be rewound from the roll when stored for a long period of time, or a large force may be required for rewinding. FIG. 1 shows an example of a conventional adhesive tape roll. When the conventional adhesive tape 1 is wound in a roll shape, stress is applied in the core direction of the roll, so that the adhesive 2 of the adhesive tape may seep out to the side surface of the roll when stored for a long period of time. Since the exuded adhesive 2 adheres to another exuded adhesive 2, the adhesive tape cannot be rewound from the roll, or a large force is required for rewinding. In particular, when the adhesive tape is stored at a high temperature, the adhesive tends to seep out to the side surface, so that the above phenomenon may easily occur.

On the other hand, when an adhesive tape is used to protect the surface of an electronic component or the like, the adhesive tape is required to have the ability to follow the unevenness of the adherend. For example, in order to make the adhesive tape follow the high unevenness of the adherend, it is necessary to make the adhesive layer of the adhesive tape thicker. However, when the adhesive tape having such a thick adhesive layer is rolled. Since the adhesive oozes out to the side surface more than the normal adhesive tape, it may be more difficult to rewind from the roll.

In view of the above problems, the present invention provides an adhesive tape capable of suppressing rewinding failure from the roll when stored for a long time even when having a thick adhesive layer, and an adhesive tape roll made of the adhesive tape. The purpose is.

The present invention is a long adhesive tape in which a base material, an adhesive layer and a release film are laminated in this order. The adhesive tape is sandwiched between two SUS304 plates, and a load of 1 kg is applied at 23 ° C. The ratio of the amount of exudation of the adhesive layer after 1 hour and the amount of exudation of the adhesive layer after 24 hours (the amount of exudation after 24 hours / the amount of exudation after 1 hour) when applied is 4 or less. It is an adhesive tape.
Hereinafter, the present invention will be described in detail.

The adhesive tape of the present invention is a long adhesive tape in which a base material, an adhesive layer, and a release film are laminated in this order.
Here, the long shape refers to a shape having a long side long enough to form a roll shape or a shape rewound from the roll shape. In the present specification, the direction orthogonal to the long side direction is referred to as the width direction. In addition, a roll-shaped body that is rewound and cut is also included in a long shape. When the adhesive tape is rewound from a roll and cut, the long side is the side that hits the long side before cutting, regardless of the size after cutting. In a preferred embodiment, the side corresponding to the long side before cutting coincides with the long side of the adhesive tape.

In the adhesive tape of the present invention, when the adhesive tape is sandwiched between two SUS304 plates and a load of 1 kg is applied at 23 ° C., the amount of exudation of the adhesive layer after 1 hour and the adhesive after 24 hours The ratio to the amount of exudation of the layer (amount of exudation after 24 hours / amount of exudation after 1 hour) is 4 or less.
The ratio of the amount of exudation of the adhesive layer after 1 hour when a load of 1 kg is applied to the adhesive tape and the amount of exudation of the adhesive layer after 24 hours (hereinafter referred to as the exudation amount ratio) is 4 or less. Therefore, even when the adhesive tape is stored in a roll form for a long period of time, it is possible to suppress the seepage of the adhesive layer to the roll side surface and suppress the rewinding failure. From the viewpoint of further suppressing unwinding failure, the preferable upper limit of the exudation amount ratio is 3.8, the more preferable upper limit is 3.5, the further preferable upper limit is 3.2, the further preferable upper limit is 3, and the particularly preferable upper limit is 2. 8.8, a particularly preferred upper limit is 2.7, and a very preferred upper limit is 2.6. The lower limit of the exudation amount ratio is not particularly limited, but if the adhesive slightly exudes to the side surface, the interleaving paper to be attached to both sides of the roll can be more reliably fixed to prevent unwinding, and the unwinding can be prevented. It is preferably 1, more preferably 1.2, still more preferably 1.5, and even more preferably 1.8, because it can suppress the above. The exudation amount ratio can be adjusted by the type of the pressure-sensitive adhesive layer and the combination of two or more types of pressure-sensitive adhesives. Specifically, the exudation amount ratio can be measured by the following method.

Here, FIG. 2 shows a schematic diagram illustrating the method for measuring the exudation amount ratio. In the measurement of the exudation amount ratio, first, the adhesive tape is cut into 5 cm × 5 cm. Next, as shown in FIG. 2A, the cut adhesive tape 3 is sandwiched between two 10 cm × 10 cm × 1 cm SUS304 plates 4 so that the adhesive tape 3 is located at the center of the SUS304 plate 4. .. Then, a 1 kg weight 5 (suitable for JIS B 7609: 2008 weight. For example, brass chrome-plated F2 grade (first grade) weight manufactured by Shinko Denshi Co., Ltd.) is placed in the center of the laminate of the SUS304 plate 4 and the adhesive tape 3. And let stand for 1 hour in an environment of 23 ° C. and 50% RH. After standing, the adhesive tape 3 is taken out, and as shown in FIG. 2B, the length of the adhesive layer exuded from the base material at the midpoints 6 (4 points) on each side of the adhesive tape using an optical microscope. Is measured, and the average value is taken as the amount of exudation after 1 hour. Subsequently, the same measurement is performed except that the standing time is set to 24 hours, and the amount of exudation after 24 hours is obtained. The exudation amount ratio is calculated from the obtained 1-hour post-ooze amount and 24-hour post-ooze amount.

The adhesive tape of the present invention preferably has a gel fraction of 50% or more.
When the gel fraction of the adhesive tape is within the above range, even when the adhesive tape is stored in a roll form for a long period of time, the adhesive layer is suppressed from seeping out to the roll side surface, and rewinding failure is suppressed. be able to. From the viewpoint of further suppressing the seepage of the pressure-sensitive adhesive layer to the roll side surface and increasing the adhesive strength, the more preferable lower limit of the gel fraction of the adhesive tape is 55%, the further preferable lower limit is 60%, and the further preferable lower limit is 62%. A particularly preferred lower limit is 65%, and a particularly preferred lower limit is 70%. The preferable upper limit of the gel fraction of the adhesive tape is 95%, the more preferable upper limit is 90%, the further preferable upper limit is 85%, and the further preferable upper limit is 80%. The gel fraction can be measured by the following method.

The adhesive tape cut to 50 mm × 50 mm is immersed in 100 ml of ethyl acetate, and shaken with a shaker at a temperature of 23 ° C. and 200 rpm for 24 hours. After shaking, a metal mesh (opening # 200 mesh) is used to absorb ethyl acetate and ethyl acetate and separate the swollen adhesive tape. The separated adhesive tape is dried under the condition of 110 ° C. for 1 hour. The weight of the adhesive tape containing the metal mesh after drying is measured, and the gel fraction of the adhesive tape is calculated using the following formula.
Gel fraction (% by weight) = 100 x (W _1- W ₂ ) / W ₀
(W ₀ : Weight of initial adhesive tape, W ₁ : Weight of adhesive tape including metal mesh after drying, W ₂ : Initial weight of metal mesh)

The adhesive tape of the present invention preferably has a thickness of 100 μm or more and 500 μm or less.
When the thickness of the adhesive tape of the present invention is within the above range, the adherend can be reliably protected by sufficiently following the irregularities even when used on an adherend having large irregularities. From the same viewpoint, the more preferable lower limit of the thickness of the adhesive tape is 150 μm, the more preferable lower limit is 200 μm, the more preferable upper limit is 480 μm, and the further preferable upper limit is 450 μm.

The base material is not particularly limited, and for example, a polyolefin resin film, a polyester resin film, an ethylene-vinyl acetate copolymer, a modified olefin resin film, a polyvinyl chloride resin film, a polyurethane resin film, and a cycloolefin polymer. Examples thereof include a resin film, an acrylic resin film, a polycarbonate film, an ABS (acrylonitrile-butadiene-styrene) resin film, a polyamide film, a polyurethane film, and a polyimide film. Examples of the polyolefin-based resin film include polyethylene films and polypropylene films. Examples of the polyester-based resin film include polyethylene terephthalate (PET) film and polyethylene naphthalate (PEN) film. Examples of the modified olefin resin film include ethylene-acrylic acid ester copolymers. When the present invention is used as a protective film, a substrate having a high elastic modulus is preferable because it can exhibit higher peelability. Further, when it is desired to confirm the state of the adherend through the adhesive tape, a substrate having a relatively low haze value (haze is preferably 2 or less, more preferably 1.5 or less) is preferable.

The thickness of the base material is not particularly limited, but a preferable lower limit is 10 μm and a preferable upper limit is 250 μm. When the thickness of the base material is within this range, the adhesive tape has an appropriate elasticity and is excellent in handleability. From the same viewpoint, the more preferable lower limit of the thickness of the base material is 12 μm, the more preferable upper limit is 230 μm, the further preferable lower limit is 20 μm, the further preferable upper limit is 200 μm, the further preferable lower limit is 25 μm, and the further preferable upper limit is 188 μm, particularly. The preferred lower limit is 30 μm, and the particularly preferred upper limit is 180 μm.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include an acrylic pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive. Of these, acrylic adhesives are preferable because their physical properties can be easily adjusted and they can be applied to a wide range of adherends. Further, the adhesive may be a curable adhesive or a non-curable adhesive, but the adhesive tape can be easily peeled off by stimulating and curing the adhesive tape. It is preferably a curable pressure-sensitive adhesive.

Examples of the curable pressure-sensitive adhesive include a photo-curable pressure-sensitive adhesive that is cross-linked and cured by light irradiation, and a thermosetting pressure-sensitive adhesive that is cross-linked and cured by heating.
Examples of the photocurable pressure-sensitive adhesive include a photo-curable pressure-sensitive adhesive containing a polymerizable polymer as a main component and a photopolymerization initiator.
Examples of the thermosetting pressure-sensitive adhesive include a thermosetting pressure-sensitive adhesive containing a polymerizable polymer as a main component and a thermosetting initiator.

For the polymerizable polymer, for example, a (meth) acrylic polymer having a functional group in the molecule (hereinafter, referred to as a functional group-containing (meth) acrylic polymer) is synthesized in advance and reacts with the functional group in the molecule. It can be obtained by reacting a functional group to be subjected to a compound having a radically polymerizable unsaturated bond (hereinafter referred to as a functional group-containing unsaturated compound).

The functional group-containing (meth) acrylic polymer comprises an acrylic acid alkyl ester and / or a methacrylate alkyl ester, a functional group-containing monomer, and, if necessary, another modifying monomer copolymerizable with these. It is obtained by copolymerizing by a conventional method. The acrylic acid alkyl ester and / or methacrylic acid alkyl ester preferably has an alkyl group having an alkyl group usually in the range of 2 to 18 (preferably in the range of 4 to 12). The weight average molecular weight of the functional group-containing (meth) acrylic polymer is usually about 200,000 to 2,000,000.

Examples of the functional group-containing monomer include a carboxyl group-containing monomer such as acrylate and methacrylic acid, a hydroxyl group-containing monomer such as hydroxyethyl acrylate and hydroxyethyl methacrylate, and an epoxy such as glycidyl acrylate and glycidyl methacrylate. Group-containing monomers can be mentioned. Further, isocyanate group-containing monomers such as isocyanate ethyl acrylate and ethyl methacrylate and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate can also be mentioned.
In the present invention, acrylic acid and / or methacrylic acid may be contained as the functional group-containing monomer from the viewpoint of improving heat resistance.

Examples of the other copolymerizable monomer for modification include various monomers used in general (meth) acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

As the functional group-containing unsaturated compound to be reacted with the functional group-containing (meth) acrylic polymer, the same one as the above-mentioned functional group-containing monomer is used depending on the functional group of the functional group-containing (meth) acrylic polymer. it can. For example, when the functional group of the functional group-containing (meth) acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used. When the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used. When the functional group is an amino group, an epoxy group-containing monomer is used.

Examples of the photopolymerization initiator include those that are activated by irradiating light having a wavelength of 250 to 800 nm. Examples of such photopolymerization initiators include acetophenone derivative compounds such as methoxyacetophenone, benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether, ketal derivative compounds such as benzyl dimethyl ketal and acetophenone diethyl ketal, and the like. Examples include phosphine oxide derivative compounds. Further, bis (η5-cyclopentadienyl) titanosen derivative compound, benzophenone, Michler ketone, chlorothioxanthone, todecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexylphenylketone, 2-hydroxymethylphenylpropane and the like can also be mentioned. These photopolymerization initiators may be used alone or in combination of two or more.

Examples of the thermal polymerization initiator include those that generate active radicals that are decomposed by heat and initiate polymerization curing. Specifically, for example, dicumyl peroxide, di-t-butyl peroxide, t-butylperoxybenzoale, t-butylhydroperoxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, etc. Examples thereof include paramentan hydroperoxide and di-t-butyl peroxide.
Of these thermal polymerization initiators, those commercially available are not particularly limited, but for example, perbutyl D, perbutyl H, perbutyl P, perpenta H (all of which are manufactured by NOF CORPORATION) and the like are suitable. These thermal polymerization initiators may be used alone or in combination of two or more.

The photocurable pressure-sensitive adhesive and the thermosetting pressure-sensitive adhesive preferably further contain a radically polymerizable polyfunctional oligomer or monomer. By containing a radically polymerizable polyfunctional oligomer or monomer, photocurability and thermosetting are improved.
The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5000 or less so that the pressure-sensitive adhesive layer can be efficiently reticulated by heating or irradiation with light. Moreover, the number of radically polymerizable unsaturated bonds in the molecule is 2 to 20.

The polyfunctional oligomer or monomer is, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or the same methacrylate as above. Kind and the like. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and the same methacrylates as described above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

The curable pressure-sensitive adhesive may contain a silicone compound having a functional group that can be crosslinked with the curable pressure-sensitive adhesive. By blending the silicone compound, the silicone compound bleeds out to the interface of the adherend at the time of peeling, and the peeling can be facilitated. Further, since the silicone compound has a functional group that can be crosslinked with the curable pressure-sensitive adhesive, it chemically reacts with the curable pressure-sensitive adhesive by light irradiation or heating and is incorporated into the curable pressure-sensitive adhesive. The silicone compound does not adhere to the adherend and contaminate it. Further, by blending the silicone compound, the effect of preventing the adhesive residue on the adherend is also exhibited. Examples of functional groups that can be crosslinked with the curable pressure-sensitive adhesive include double bonds.

The pressure-sensitive adhesive layer may further contain an inorganic filler such as fumed silica. By blending an inorganic filler, the cohesive force of the pressure-sensitive adhesive layer is increased. Therefore, when the pressure-sensitive adhesive layer contains an inorganic filler such as fumed silica, the pressure-sensitive adhesive tape can be more easily peeled off from the adherend without leaving adhesive residue when the pressure-sensitive adhesive tape is no longer needed.

The pressure-sensitive adhesive layer preferably contains a cross-linking agent. When the pressure-sensitive adhesive layer contains a cross-linking agent, the cohesive force of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is enhanced, and the exudation amount ratio can be easily satisfied. Examples of the above-mentioned cross-linking agent include isocyanate-based cross-linking agents and epoxy-based cross-linking agents.

The content of the cross-linking agent in the pressure-sensitive adhesive layer is not particularly limited, but is preferably 0.01 to 20% by weight. When the cross-linking agent is contained in the above range, the cohesive force of the pressure-sensitive adhesive component can be enhanced to further improve the initial adhesive force, and the exudation amount ratio can be easily satisfied. A more preferable lower limit of the blending amount of the cross-linking agent in the pressure-sensitive adhesive layer is 2% by weight, a further preferable lower limit is 3% by weight, a more preferable upper limit is 10% by weight, a further preferable upper limit is 7.5% by weight, and further. A more preferred upper limit is 5% by weight.

The pressure-sensitive adhesive layer may contain known additives such as plasticizers, resins, surfactants, waxes, and fine particle fillers. The above additives may be used alone or in combination of two or more.

The pressure-sensitive adhesive layer preferably has a sol component having a weight average molecular weight of 300,000 or more.
The pressure-sensitive adhesive usually contains a gel component and a sol component, and when a force is applied, the pressure-sensitive adhesive is deformed and flows mainly by the movement of the sol component. In the adhesive tape of the present invention, by increasing the weight average molecular weight of the sol component, the sol component becomes difficult to move even when a force is applied, and it is possible to suppress the exudation of the pressure-sensitive adhesive layer over time. A more preferable lower limit of the weight average molecular weight of the sol component is 300,000, a further preferable lower limit is 500,000, and a further preferable lower limit is 700,000. The upper limit of the weight average molecular weight of the sol component is not particularly limited, but is preferably 1.5 million or less from the viewpoint of adhesive strength. The weight average molecular weight of the sol component can be measured by the following method.

Only 0.1 g of the adhesive layer of the adhesive tape is scraped off, immersed in 50 ml of ethyl acetate, and shaken with a shaker at a temperature of 23 ° C. and 200 rpm for 24 hours (hereinafter, the scraped adhesive layer). This is called an adhesive composition). After shaking, a metal mesh (opening # 200 mesh) is used to separate the ethyl acetate-soluble component and the ethyl acetate-absorbing and swollen pressure-sensitive adhesive composition. By performing gel permeation chromatography (GPC) on the ethyl acetate-soluble content after separation, the weight average molecular weight of the sol component of the pressure-sensitive adhesive layer is obtained as the polystyrene-equivalent molecular weight. The GPC can be measured by using, for example, the following devices and conditions.
Gel Permeation Chromatograph: 2690 Separations Module, Waters Column: GPC LF-804, Showa Denko Detector: Differential Refractometer Sample Flow Rate: 1 ml / min
Column temperature: 40 ° C

The method of setting the weight average molecular weight of the sol component of the pressure-sensitive adhesive layer in the above range is not particularly limited, and for example, a method of adjusting the number of crosslinkable functional groups of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer and the amount of the cross-linking agent , A method of using two types of a pressure-sensitive adhesive having a crosslinkable functional group (for example, a curable pressure-sensitive adhesive as described above) and a pressure-sensitive adhesive having no crosslinkable functional group can be mentioned as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer. .. Among them, since only the weight average molecular weights of the gel component and the sol component can be adjusted separately, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer includes a pressure-sensitive adhesive having a crosslinkable functional group and a pressure-sensitive adhesive having no crosslinkable functional group. The method using the kind is preferable.
In the case of the method using the above two types of pressure-sensitive adhesives, the pressure-sensitive adhesive having a crosslinkable functional group becomes a gel component, and the pressure-sensitive adhesive having no crosslinkable functional group becomes a sol component. The blending ratio of the pressure-sensitive adhesive having a crosslinkable functional group and the pressure-sensitive adhesive having no crosslinkable functional group is not particularly limited, but from the viewpoint of suppressing the exudation of the pressure-sensitive adhesive layer over time, the crosslinkable functional group accounts for the entire pressure-sensitive adhesive. The preferable lower limit of the content of the pressure-sensitive adhesive having is 50% by weight, the preferable upper limit is 90% by weight, the more preferable lower limit is 65% by weight, and the more preferable upper limit is 80% by weight.

The pressure-sensitive adhesive having no crosslinkable functional group is not particularly limited, and examples thereof include acrylic pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and urethane-based pressure-sensitive adhesives. Of these, an acrylic pressure-sensitive adhesive is preferable because it is easy to adjust the weight average molecular weight.
The weight average molecular weight of the pressure-sensitive adhesive having no crosslinkable functional group is not particularly limited, but a preferable lower limit is 300,000, a more preferable lower limit is 500,000, and a further preferable lower limit is 700,000. The upper limit of the weight average molecular weight of the pressure-sensitive adhesive having no crosslinkable functional group is not particularly limited, but is preferably 1.5 million or less from the viewpoint of adhesive strength.

The thickness of the pressure-sensitive adhesive layer is preferably 20 μm or more, more preferably 30 μm or more, further preferably 40 μm or more, and even more preferably 50 μm or more. The thickness of the pressure-sensitive adhesive layer is particularly preferably 70 μm or more, particularly preferably 80 μm or more, very preferably 100 μm or more, still more preferably 150 μm or more, still more preferably 200 μm or more. Most preferred.
When the thickness of the adhesive layer is equal to or greater than the above lower limit, even when the adherend has large irregularities, the adhesive tape can be reliably attached by sufficiently following the irregularities. You can fully protect your body. In the conventional adhesive tape, when such a thick adhesive layer is formed to form a roll, the adhesive layer exudes to the side surface of the roll after long-term storage, and the roll rewinding failure is likely to occur. The adhesive tape of the present invention is less likely to cause rewinding failure even if a thick adhesive layer is formed. The upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1000 μm, more preferably 700 μm, still more preferably 500 μm, still more preferably, from the viewpoint of preventing wrinkles from being generated due to bending deformation when passing through a transport roller during processing. Is 400 μm.

The release film is laminated on the surface of the pressure-sensitive adhesive layer in contact with the adherend, and has a role of reducing the charge generated when the roll-shaped pressure-sensitive adhesive tape is rewound and making it difficult to attract foreign substances in the environment. Further, by laminating the release film, the adhesive surface does not come into contact with the transport roller during manufacturing, so that the smoothness of the adhesive surface can be maintained and the adhesion of foreign matter can be suppressed.

The thickness of the release film is not particularly limited, but a preferable lower limit is 15 μm, a more preferable lower limit is 25 μm, a preferable upper limit is 188 μm, and a more preferable upper limit is 125 μm. When the thickness of the release film is within the above range, an adhesive tape having excellent handleability can be obtained.

The material of the release film is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate and polyethylene naphthalate, and polyolefins such as polypropylene and polyethylene. Of these, polyethylene terephthalate is preferable.

The method for producing the adhesive tape of the present invention is not particularly limited. For example, the above-mentioned polymerizable polymer, the above-mentioned pressure-sensitive adhesive having no crosslinkable functional group, a light or thermal polymerization initiator, and various additives as necessary are added to the solvent and mixed to obtain adhesion. Examples thereof include a method of preparing an agent solution, applying the pressure-sensitive adhesive solution on the substrate, and drying the pressure-sensitive adhesive solution to form a pressure-sensitive adhesive layer, and then laminating a release film on the pressure-sensitive adhesive layer.

The use of the adhesive tape of the present invention is not particularly limited, but it can be suitably used as a protective tape for protecting electronic components in the manufacture of electronic components such as semiconductor wafers. Among them, the adhesive tape of the present invention is particularly suitable as a protective tape for a high bump wafer having a high bump height because rewinding failure does not occur when the adhesive layer is made into a roll shape even if the adhesive layer is thickened. Can be used. The bump height of the high bump wafer is not particularly limited, but is preferably 100 μm or more, more preferably 150 μm or more, still more preferably 200 μm or more, and usually 400 μm or less. In the case of a high bump wafer having such a bump height, the effect of the present invention is greatly exhibited.

The adhesive tape of the present invention can suppress rewinding defects that occur when the adhesive tape is made into a roll. An adhesive tape roll made of the adhesive tape of the present invention is also one of the present inventions.
The roll width of the adhesive tape roll of the present invention is not particularly limited, but is preferably 20 mm or more, more preferably 30 mm or more, and further preferably 40 mm or more. The roll width of the adhesive tape roll of the present invention is preferably 1500 mm or less, more preferably 1300 mm or less, still more preferably 1100 mm or less, still more preferably 900 mm or less, particularly preferably 700 mm or less, particularly preferably 500 mm or less, very much. It is preferably 300 mm or less. The diameter of the adhesive tape roll of the present invention is not particularly limited, but is preferably 5000 mm or less, more preferably 3000 mm or less, still more preferably 1000 mm or less, and usually 25 mm or more.

The method for producing the adhesive tape roll of the present invention is not particularly limited, and for example, it can be produced by winding the adhesive tape produced by the above-mentioned method for producing an adhesive tape around a winding core.

The application of the adhesive tape roll of the present invention is not particularly limited, but it can be suitably used as a protective tape for protecting electronic components in the manufacture of electronic components such as semiconductor wafers. Among them, the adhesive tape roll of the present invention can be particularly preferably used as a protective tape for a high bump wafer having a high bump height because rewinding failure does not occur even if the adhesive layer is thickened. The bump height of the high bump wafer is not particularly limited, but when it is preferably 100 μm or more, more preferably 150 μm or more, and further preferably 200 μm or more, the effect of the present invention is largely exhibited.

According to the present invention, it is possible to provide an adhesive tape capable of suppressing rewinding failure from the roll when stored for a long time even when having a thick adhesive layer, and an adhesive tape roll made of the adhesive tape. ..

It is a figure which showed an example of the conventional adhesive tape roll. It is a schematic diagram explaining the measuring method of the exudation amount ratio.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Manufacturing of adhesive A)
A reactor equipped with a thermometer, a stirrer, and a cooling tube was prepared, and 94 parts by weight of 2-ethylhexyl acrylate as the (meth) acrylic acid alkyl ester and 6 parts by weight of hydroxyethyl methacrylate as the functional group-containing monomer were prepared in the reactor. , 0.01 part by weight of lauryl mercaptan and 80 parts by weight of ethyl acetate were added, and then the reactor was heated to start reflux. Subsequently, 0.01 part by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added as a polymerization initiator into the reactor, and the polymerization was started under reflux. It was. Next, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added 1 hour and 2 hours after the start of the polymerization, and further, the polymerization was started. After 4 hours from the above, 0.05 parts by weight of t-hexyl peroxypivalate was added to continue the polymerization reaction. Then, 8 hours after the start of the polymerization, an ethyl acetate solution of a functional group-containing (meth) acrylic polymer having a solid content of 55% by weight and a weight average molecular weight of 600,000 was obtained.
To 100 parts by weight of the resin solid content of the obtained ethyl acetate solution containing a functional group-containing (meth) acrylic polymer, 3.5 parts by weight of 2-isocyanatoethyl methacrylate was added as a functional group-containing unsaturated compound to react. To obtain a polymerizable polymer. Then, 1 part by weight of the photopolymerization initiator and 0.15 parts by weight of the isocyanate curing agent were mixed with 100 parts by weight of the resin solid content of the ethyl acetate solution of the obtained polymerizable polymer, and the ethyl acetate solution of the pressure-sensitive adhesive A was mixed. Got The following photopolymerization initiators and isocyanate curing agents were used.
Photopolymerization initiator: Nippon Sibel Hegner, Esacure One Isocyanate Hardener: Tosoh, Coronate L

(Manufacturing of adhesive B)
(Manufacturing method of adhesive having no crosslinkable functional group)
A reactor equipped with a thermometer, a stirrer, and a cooling tube is prepared, and 100 parts by weight of 2-ethylhexyl acrylate, 0.1 part by weight of lauryl mercaptan, and 80 parts by weight of ethyl acetate are contained in the reactor as (meth) acrylic acid alkyl ester. After adding parts by weight, the reactor was heated to initiate reflux. Subsequently, 0.01 part by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added as a polymerization initiator into the reactor, and the polymerization was started under reflux. It was. Next, 0.01 parts by weight of 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane was added 1 hour and 2 hours after the start of the polymerization, and further, the polymerization was started. After 4 hours from the above, 0.05 parts by weight of t-hexyl peroxypivalate was added to continue the polymerization reaction. Then, 8 hours after the start of the polymerization, an ethyl acetate solution of a (meth) acrylic polymer (adhesive B) having a solid content of 55% by weight and a weight average molecular weight of 300,000 was obtained.
(Manufacturing of adhesive C)
An ethyl acetate solution of the pressure-sensitive adhesive C having a weight average molecular weight of 500,000 was obtained in the same manner as the pressure-sensitive adhesive B except that lauryl mercaptan was added to 0.05 parts by weight.
(Manufacturing of adhesive D)
An ethyl acetate solution of the pressure-sensitive adhesive D having a weight average molecular weight of 700,000 was obtained in the same manner as the pressure-sensitive adhesive B except that lauryl mercaptan was added to 0.02 parts by weight.
(Manufacturing of adhesive E)
An ethyl acetate solution of the pressure-sensitive adhesive E having a weight average molecular weight of 150,000 was obtained in the same manner as the pressure-sensitive adhesive B except that the lauryl mercaptan was added to 0.15 parts by weight.

(Example 1)
(1) Production of Adhesive Tape The ethyl acetate solution of the adhesive B is added to 50 parts by weight of the solid content of the ethyl acetate solution of the adhesive A and mixed so that the solid content is 50 parts by weight. An adhesive solution was obtained. The obtained pressure-sensitive adhesive solution is applied on the release-treated surface of a polyethylene terephthalate film (release film) having a thickness of 50 μm on one side with a comma coater so that the thickness of the dry film is 50 μm. , 110 ° C. for 5 minutes. Next, the base material and the pressure-sensitive adhesive surface coated and dried on the above-mentioned release film were bonded together. Then, it was statically cured at 40 ° C. for 3 days to obtain an adhesive tape composed of a base material / adhesive layer / release film.

(2) Measurement of exudation amount ratio First, the adhesive tape was cut into 5 cm × 5 cm. Next, as shown in FIG. 2A, the cut adhesive tape 3 is sandwiched between two 10 cm × 10 cm × 1 cm SUS304 plates 4 so that the adhesive tape 3 is located at the center of the SUS304 plate 4. That's it. Then, a 1 kg weight 5 (manufactured by Shinko Denshi Co., Ltd., brass chrome-plated F2 grade (first grade) weight, conforming to JIS B 7609: 2008 weight) is placed in the center of the laminate of the SUS304 plate 4 and the adhesive tape 3. , 23 ° C., and allowed to stand for 1 hour in an environment of 50% RH. After standing, the adhesive tape 3 is taken out, and as shown in FIG. 2B, the length of the adhesive layer exuded from the base material at the midpoint (measurement point) 6 on each side of the adhesive tape using an optical microscope. Was measured, and the average value was taken as the amount of exudation after 1 hour. Subsequently, the same measurement was performed except that the standing time was set to 24 hours, and the amount of exudation after 24 hours was obtained. The exudation amount ratio was calculated from the obtained 1-hour post-ooze amount and 24-hour post-ooze amount.

(3) Measurement of Gel Fragment of Adhesive Tape An adhesive tape cut to 50 mm × 50 mm was immersed in 100 ml of ethyl acetate, and shaken with a shaker at a temperature of 23 ° C. and 200 rpm for 24 hours. After shaking, the adhesive tape that absorbed ethyl acetate and ethyl acetate and swollen was separated using a metal mesh (opening # 200 mesh). The separated adhesive tape was dried under the condition of 110 ° C. for 1 hour. The weight of the adhesive tape containing the metal mesh after drying was measured, and the gel fraction of the adhesive tape was calculated using the following formula.
Gel fraction (% by weight) = 100 x (W _1- W ₂ ) / W ₀
(W ₀ : Weight of initial adhesive tape, W ₁ : Weight of adhesive tape including metal mesh after drying, W ₂ : Initial weight of metal mesh)

(4) Measurement of weight average molecular weight of sol component of adhesive layer Only 0.1 g of the adhesive layer of the adhesive tape was scraped off and immersed in 50 ml of ethyl acetate, and the temperature was 23 ° C. and 200 rpm with a shaker. It was shaken for 24 hours (hereinafter, the scraped adhesive layer is referred to as an adhesive composition). After shaking, a metal mesh (opening # 200 mesh) was used to separate the ethyl acetate-soluble component and the ethyl acetate-absorbed and swollen pressure-sensitive adhesive composition. Gel permeation chromatography (GPC) was performed on the ethyl acetate-soluble content after separation to obtain the weight average molecular weight of the sol component of the pressure-sensitive adhesive layer as the polystyrene-equivalent molecular weight. The details of GPC are as follows.
Gel Permeation Chromatograph: 2690 Separations Module, Waters Column: GPC LF-804, Showa Denko Detector: Differential Refractometer Sample Flow Rate: 1 ml / min
Column temperature: 40 ° C

(Examples 2 to 12, Comparative Examples 1 to 3)
An adhesive tape was obtained in the same manner as in Example 1 except that the composition of the adhesive and the thickness of the adhesive layer were as shown in Tables 1 and 2, and the exudation amount ratio, the gel fraction of the adhesive tape, and the adhesive layer were obtained. The weight average molecular weight of the sol component was measured.

<Evaluation>
The adhesive tapes obtained in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Tables 1 and 2.

(Evaluation of rewindability)
The obtained adhesive tape was wound around a core of 6-inch ABS resin to form a roll-shaped body having a width of 550 mm and a winding length of 30 m (winding tension: 80 N / m). Then, the obtained adhesive tape roll was allowed to stand for 1 month under the condition of 40 ° C. The roll-shaped body after standing was rewound, and the rewindability was evaluated according to the following criteria.
◎: All can be smoothly rewound without adhesion on the side of the roll. ○: Although there is partial adhesion on the core side of the side of the roll, it can be rewound by applying light force. ×: Side of the roll Adhesive and all rewinding is impossible

1 Conventional adhesive tape 2 Adhesive 3 Adhesive tape 4 SUS304 plate 5 Weight 6 Midpoint of each side of adhesive tape

Claims

A long adhesive tape in which a base material, an adhesive layer, and a release film are laminated in this order.
The amount of exudation of the adhesive layer after 1 hour and the amount of exudation of the adhesive layer after 24 hours when the adhesive tape was sandwiched between two SUS304 plates and a load of 1 kg was applied at 23 ° C. Adhesive tape having a ratio (amount of exudation after 24 hours / amount of exudation after 1 hour) of 4 or less.
The adhesive tape according to claim 1, wherein the adhesive tape has a gel fraction of 50% or more.
The adhesive tape according to claim 1 or 2, wherein the weight average molecular weight of the sol component of the adhesive layer is 300,000 or more.
An adhesive tape roll comprising the adhesive tape according to claim 1, 2 or 3.