WO2019069541A1

WO2019069541A1 - Pressure-sensitive adhesive tape

Info

Publication number: WO2019069541A1
Application number: PCT/JP2018/027688
Authority: WO
Inventors: 悠介山成; 齋藤　誠; 真覚樋口; 健太定司
Original assignee: 日東電工株式会社
Priority date: 2017-10-02
Filing date: 2018-07-24
Publication date: 2019-04-11
Also published as: JP7312299B2; JP2022118138A

Abstract

Provided is a pressure-sensitive adhesive tape having excellent conformability to rugged portions. The pressure-sensitive adhesive tape of the present invention comprises a base layer and a pressure-sensitive adhesive layer disposed on at least one surface of the base layer, and has a dimensional change at 23°C of 0.20-0.39.

Description

Adhesive tape

The present invention relates to an adhesive tape.

Adhesive tapes have been used to fix structures of various shapes (eg, Patent Documents 1 to 3). However, when an adhesive tape is attached to a corner (for example, a corner of a wall) or a bent portion (for example, a movable bent portion of a folding member), stress is generated in the adhesive tape. Uneven follow-up can not be achieved sufficiently.

Specifically, when an adhesive tape is attached to a corner or a bent portion, the following problems occur.

When the pressure-sensitive adhesive tape is bent at an angle, a pressure is exerted on the bent inner diameter side, so that deformation of the pressure-sensitive adhesive tape itself occurs in an attempt to relieve the force. Specifically, for example, wrinkles are likely to occur.

When the adhesive tape is bent at an angle, a tensile stress acts on the bent outer diameter side. For this reason, when the stress is relieved, floating from the adherend occurs.

The thickness of the portion where the pressure-sensitive adhesive tape is bent or pulled is greatly changed, and even in such a state, wrinkles may easily occur or lifting may occur. For example, when the pressure-sensitive adhesive tape is pulled, the thickness of the pressure-sensitive adhesive tape is significantly reduced, and a float from an adherend easily occurs.

As described above, in the case of the conventional pressure-sensitive adhesive tape, follow-up can not be sufficiently achieved.

In particular, when the adhesive tape is attached to the movable bending portion, the bending is repeated, so that the adhesive tape has a broken mark (so-called "squeeze") on the movable bending portion.

JP, 2015-165023, A JP, 2016-029155, A JP, 2016-113506, A

An object of the present invention is to provide a pressure-sensitive adhesive tape excellent in unevenness followability.

The adhesive tape of the present invention is
A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one side of a substrate layer,
The dimensional change at 23 ° C. is 0.20 to 0.39.

In one embodiment, the pressure-sensitive adhesive tape of the present invention has a Young's modulus at 23 ° C. of 0.2 MPa to 25 MPa.

In one embodiment, the pressure-sensitive adhesive tape of the present invention has a maximum stress at 100% tension at a tension rate of 300 mm / min at 23 ° C. of 0.1 MPa to 6.0 MPa.

In one embodiment, the pressure-sensitive adhesive tape according to the present invention has a stress B after maintaining the 100% tension state for 1 second against a stress A applied immediately after 100% tension at a tension rate of 300 mm / min at 23 ° C. Ratio (B / A) is 0.7 to 1.0.

In one embodiment, the adhesive strength of the pressure-sensitive adhesive layer to a SUS plate at a tensile speed of 300 mm / min and 180 degrees peel at 23 ° C. is 5 N / 20 mm or more.

In one embodiment, the adhesive tape of the present invention has a total thickness d of 1 μm to 500 μm.

In one embodiment, the ratio (d1 / d) of the total thickness d1 of the pressure-sensitive adhesive layer to the total thickness d is 0.7 or less.

In one embodiment, the base layer contains at least one polar functional group-containing polymer selected from condensation polymers and polyaddition polymers.

In one embodiment, the polar functional group-containing polymer is at least one selected from polyamides, polyurethanes and polyureas.

In one embodiment, the polar functional group-containing polymer has at least one selected from an ether bond and an ester bond.

In one embodiment, the pressure-sensitive adhesive layer contains at least one selected from an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive tape excellent in uneven | corrugated followable | trackability can be provided.

FIG. 1 is a schematic cross-sectional view showing an embodiment in which the pressure-sensitive adhesive tape of the present invention is a single-sided pressure-sensitive adhesive tape. FIG. 2 is a schematic sectional view showing an embodiment in which the pressure-sensitive adhesive tape of the present invention is a double-sided pressure-sensitive adhesive tape. FIG. 3 is an explanatory view for calculating the dimensional change rate.

«« Adhesive tape »»
The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one side of a substrate layer. That is, as shown in FIG. 1, the pressure-sensitive adhesive tape 1000 of the present invention may be a pressure-sensitive adhesive tape (single-sided pressure-sensitive adhesive tape) having the pressure-sensitive adhesive layer 200 only on one side of the base material layer 100. As shown, it may be a pressure-sensitive adhesive tape (double-sided pressure-sensitive adhesive tape) having the pressure-sensitive adhesive layers 200 a and 200 b on both sides of the base material layer 100.

The base material layer may be a single layer or two or more layers. The base material layer is preferably a single layer in that the effect of the present invention can be further developed.

The pressure-sensitive adhesive layer may be one layer or two or more layers in the pressure-sensitive adhesive layer provided on one side of the base material layer. The pressure-sensitive adhesive layer is preferably a single layer in that the effects of the present invention can be further developed.

The pressure-sensitive adhesive tape of the present invention may have any appropriate other layer other than the base material layer and the pressure-sensitive adhesive layer, as long as the effects of the present invention are not impaired.

The pressure-sensitive adhesive tape of the present invention may be provided with any suitable release liner on the surface of the pressure-sensitive adhesive layer opposite to the substrate layer for protection before use.

As the release liner, for example, the surface of a substrate (liner substrate) such as paper or plastic film is treated with silicone, the surface of the substrate (liner substrate) such as paper or plastic film is made of a polyolefin resin And laminated release liners. Examples of plastic films as liner substrates include polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, Polyurethane films, ethylene-vinyl acetate copolymer films and the like can be mentioned.

The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, still more preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

The adhesive tape of the present invention has a total thickness d of preferably 1 to 500 μm, more preferably 5 to 400 μm, still more preferably 10 to 350 μm, particularly preferably 15 to 300 μm, most preferably 20 μm to 250 μm. If the total thickness d of the pressure-sensitive adhesive tape of the present invention is within the above range, the effects of the present invention can be further exhibited.

In the pressure-sensitive adhesive tape of the present invention, the ratio (d1 / d) of the total thickness d1 of the pressure-sensitive adhesive layer to the total thickness d is preferably 0.7 or less, more preferably 0.01 to 0.65, and further It is preferably 0.05 to 0.6, particularly preferably 0.1 to 0.57, and most preferably 0.2 to 0.55. If the ratio (d1 / d) of the total thickness d1 of the pressure-sensitive adhesive layer to the total thickness d of the pressure-sensitive adhesive tape of the present invention is within the above range, the effects of the present invention can be further exhibited. The units of d and d1 are the same.

The pressure-sensitive adhesive tape of the present invention has a dimensional change at 23 ° C. of 0.20 to 0.39, preferably 0.22 to 0.37, more preferably 0.24 to 0.35, and further, It is preferably 0.25 to 0.33, particularly preferably 0.26 to 0.32, and most preferably 0.27 to 0.31. If the dimensional change rate at 23 ° C. of the pressure-sensitive adhesive tape of the present invention is within the above range, the pressure-sensitive adhesive tape of the present invention can be excellent in the followability to irregularities. When the dimensional change rate of the adhesive tape at 23 ° C. is too small outside the above range, the following property of the convex portion may be deteriorated when sticking to the convex portion of the adherend, and a float from the adherend occurs. There is a fear. If the dimensional change rate at 23 ° C. of the pressure-sensitive adhesive tape is too large outside the above range, the adhesive tape may easily flow and wrinkles may easily occur. The method of measuring the dimensional change rate will be described in detail later.

The pressure-sensitive adhesive tape of the present invention preferably has a Young's modulus at 23 ° C. of 0.2 MPa to 25 MPa, more preferably 1.0 MPa to 20 MPa, still more preferably 1.0 MPa to 15 MPa, particularly preferably 1 It is from 0 MPa to 10 MPa. If the Young's modulus at 23 ° C. of the pressure-sensitive adhesive tape of the present invention is within the above range, the effects of the present invention can be further exhibited. When the Young's modulus at 23 ° C of the adhesive tape is less than 0.2 MPa, if the adhesive tape is bent at an angle, there is a possibility that the tension on the outer diameter side can not be sufficiently maintained against the compression on the inner diameter side. It tends to change, and there is a possibility that floating from the adherend may easily occur. When the Young's modulus at 23 ° C. of the pressure-sensitive adhesive tape exceeds 25 MPa, the pressure-sensitive adhesive tape may not be easily deformed. The method of measuring Young's modulus will be described in detail later.

The adhesive tape of the present invention has a maximum stress at 100% tension at a tension rate of 300 mm / min at 23 ° C. of preferably 0.1 MPa to 6.0 MPa, more preferably 0.2 MPa to 5.8 MPa. , More preferably 0.3 MPa to 5.3 MPa, still more preferably 0.5 MPa to 4.8 MPa, particularly preferably 1.1 MPa to 4.5 MPa, and most preferably 1.7 MPa to 4.3 MPa It is. If the maximum stress at 100% tension at a tensile speed of 300 mm / min at 23 ° C. of the pressure-sensitive adhesive tape of the present invention is within the above range, the effects of the present invention can be further exhibited. If the maximum stress under 100% tension at a tension speed of 300 mm / min at 23 ° C is less than 0.1 MPa, the adhesive tape may be easily deformed, which causes problems in handleability such as processability. There is a fear. When the maximum stress at 100% tension at a tension speed of 300 mm / min at 23 ° C. exceeds 6.0 MPa, a large force may be required when the adhesive tape is bent at an angle, and the inner diameter There is a possibility that the side compressive stress may become large and wrinkles may easily occur. The method of measuring the maximum stress will be described in detail later.

The pressure-sensitive adhesive tape of the present invention has a ratio of stress B after holding the 100% tension state for 1 second to stress A applied immediately after 100% tension at a tensile speed of 300 mm / min at 23 ° C. (B / A) Is preferably 0.7 to 1.0, more preferably 0.73 to 0.97, still more preferably 0.75 to 0.95, and particularly preferably 0.77 to 0.93. And most preferably 0.80 to 0.90. Ratio of stress B after holding the 100% tension state for 1 second to stress A applied immediately after 100% tension at a tension rate of 300 mm / min at 23 ° C. of the adhesive tape of the present invention (B / A) However, within the above range, the effects of the present invention can be more manifested. The ratio (B / A) of stress B after holding the 100% tension state for 1 second to the stress A applied immediately after 100% tension at a tension rate of 300 mm / min at 23 ° C. of the adhesive tape is 0. If it is less than 7, the film may be stretched immediately, and even if it can follow, there is a possibility that it can not be re-laid in case of a wrinkle, or the thickness of the adhesive tape may be changed. The method of measuring the ratio (B / A) will be described in detail later.

The pressure-sensitive adhesive tape of the present invention has an adhesive strength to a SUS plate at a tensile speed of 300 mm / min and 180 degree peel at 23 ° C., preferably 5 N / 20 mm or more, more preferably 5 N / 20 mm. It is -100 N / 20 mm, more preferably 5 N / 20 mm to 50 N / 20 mm, particularly preferably 5 N / 20 mm to 30 N / 20 mm, most preferably 5 N / 20 mm to 20 N / 20 mm. If the adhesive strength of the pressure-sensitive adhesive layer of the present invention to the SUS plate at a tensile speed of 300 mm / min and 180 degrees peel at 23 ° C. within the above range, the effects of the present invention can be expressed more .

«Base material layer»
The thickness of the substrate layer is preferably 1 μm to 500 μm, more preferably 5 μm to 400 μm, still more preferably 10 μm to 300 μm, particularly preferably 15 μm to 200 μm, and most preferably 20 μm to 150 μm. . If the thickness of the base material layer is within the above range, the effects of the present invention can be further exhibited.

Any appropriate material may be adopted as the material of the base layer as long as the effects of the present invention are not impaired. Such materials preferably include at least one polar functional group-containing polymer selected from condensation polymers and polyaddition polymers. That is, the substrate layer preferably contains at least one polar functional group-containing polymer selected from condensation polymers and polyaddition polymers.

The content ratio of the at least one polar functional group-containing polymer selected from the condensation polymer and the polyaddition polymer in the base material layer is preferably 50% by weight to 100% in that the effect of the present invention can be further developed. % By weight, more preferably 70% by weight to 100% by weight, still more preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, most preferably 98% by weight It is up to 100% by weight.

At least one polar functional group-containing polymer selected from condensation polymers and polyaddition polymers has a polar functional group such as a carbonyl group in the polymer main chain, and is stronger in intermolecular force than radical polymerization polymers. Can work to have a network structure that does not rely on covalent bonding. A polymer having a network structure with many covalent bonds may be too elastic, and the unevenness followability may be reduced. In condensation polymers and polyaddition polymers having a network structure that does not rely on covalent bonding, the intermolecular force due to the polar functional group is weaker than the intermolecular force caused by covalent bonding, and the smaller energy (work done by stress etc. Even with energy (such as energy), it is easy to relieve stress by deformation etc., and after relaxation intermolecular force works again between polar functional groups (for example, combination of polar functional groups causing intermolecular force changes), for example, it is bent The unevenness followability can be improved, for example, by making it possible to maintain the shape.

The polar functional group-containing polymer is preferably at least one selected from polyamides, polyurethanes and polyureas. Hydrogen-bondable polar functional groups (more precisely, hydrogen-bondable polar functional groups having hydrogen donor property) -containing polymers such as polyamides, polyurethanes and polyureas have an intermolecular force of about 1/10 the energy of covalent bonds It is considered that the cleavage is possible (the combination of hydrogen bonding functional groups that produces intermolecular force changes), and the heat energy given at around room temperature or the energy generated by the work caused by stress caused by bending etc. effectively Breakage of intermolecular forces can occur. For this reason, the unevenness followability can be further improved.

The base layer more preferably includes a polar functional group-containing polymer which is a polyaddition polymer. In polyaddition polymers, monomers having various functional groups can be adopted, operations for converting monomers into polymers are easy, and various properties are imparted to polyaddition polymers by taking advantage of these features. It becomes possible.

The polar functional group-containing polymer which is a polyaddition-based polymer may have at least one selected from an ether bond and an ester bond. An ether bond can be introduced by employing a monomer having an ether bond in obtaining a polyaddition-based polymer. An ester bond can be introduced by employing a monomer having an ester bond in obtaining a polyaddition-based polymer. For example, when a polyurethane is employed as the polar functional group-containing polymer, examples of the polyurethane having an ether bond include ether-based polyurethanes. As polyurethane which has an ester bond, ester-type polyurethane is mentioned, for example.

When a monomer having an ether bond is employed in obtaining a polyaddition-based polymer, the elasticity of the polyaddition-based polymer can be weakened and molecular flexibility can be imparted. The use of a monomer having an ester bond in obtaining a polyaddition-based polymer can impart rigidity to the polyaddition-based polymer. Therefore, for example, when obtaining a polyaddition-based polymer, the elasticity and rigidity of the polyaddition-based polymer can be adjusted by appropriately combining or independently using a monomer having an ether bond and a monomer having an ester bond. As a result, the effects of the present invention can be expressed more.

When polyurethane is employed as the polar functional group-containing polymer, a hydroxyl group-containing monomer may be employed when obtaining the polyurethane. When a hydroxyl group-containing monomer is employed in obtaining a polyurethane, an isocyanate monomer and a hydroxyl group-containing monomer used in a polyaddition reaction in obtaining a polyurethane can be reacted to introduce a covalent network structure. Moreover, a hydroxyl-containing monomer can be provided collectively as a raw material of a polyurethane, and the effort of applying the raw material of a polyurethane after preparation can be simplified.

As a polar functional group containing polymer, a polyurethane is preferable at the point which can express the effect of this invention more. Polyurethane is a polymer compound synthesized by polyaddition reaction of a polyol (for example, diol) and a polyisocyanate (for example, diisocyanate) in a predetermined ratio.

As a polyol which may be used for the synthesis of polyurethane, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol And diols such as 1, 8-octanediol, polyoxytetramethylene glycol, diethylene glycol, polyethylene glycol and polypropylene glycol; polyesters which are polycondensates of the above diols with dicarboxylic acids (eg, adipic acid, azelaic acid, sebacic acid) Polyol; carbonate diol such as polyalkylene carbonate diol; and the like. These may be only 1 type and may be 2 or more types.

As polyisocyanate which may be used for synthesis of polyurethane, aromatic, aliphatic and alicyclic diisocyanates, multimers (for example, dimers and trimers) of these diisocyanates, and the like can be mentioned. Examples of the diisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,5-naphthyl diisocyanate, 1,3-phenylene diisocyanate 1,4-phenylene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4 2,4-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methyl cyclohexene Down diisocyanate, m- tetramethylxylylene diisocyanate. These may be only 1 type and may be 2 or more types.

In the polyurethane, other copolymerization components may be introduced in addition to the polyol and the polyisocyanate. Other copolymerization components include monocarboxylic acids and dicarboxylic acids, trifunctional or higher functional polycarboxylic acids, hydroxycarboxylic acids, alkoxycarboxylic acids, and derivatives thereof. The other copolymer component may be only one type or two or more types. The content of the other copolymerization component is preferably less than 30% by weight, more preferably less than 10% by weight, and still more preferably less than 5% by weight in the polyurethane.

The range of 100% modulus of the base material layer is preferably 0.5 Mpa to 10 Mpa, more preferably 1 Mpa to 9 Mpa, and still more preferably 1.5 Mpa to 8 Mpa, from the viewpoint of ease of deformation. Particularly preferably, it is 2 MPa to 7 MPa.

«Adhesive layer»
The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 500 μm, more preferably 3 μm to 300 μm, still more preferably 5 μm to 200 μm, particularly preferably 7 μm to 100 μm, and most preferably 10 μm to 70 μm. . If the thickness of the pressure-sensitive adhesive layer is within the above range, the effects of the present invention can be further developed.

The pressure-sensitive adhesive layer contains a base polymer. The base polymer may be only one type or two or more types. The content ratio of the base polymer in the pressure-sensitive adhesive layer is preferably 30% by weight to 95% by weight, more preferably 40% by weight to 90% by weight, in that the effect of the present invention can be more developed. Preferably, it is 50% by weight to 80% by weight.

The base polymer is preferably at least one selected from an acrylic polymer, a rubber polymer, a silicone polymer, and a urethane polymer from the viewpoint of achieving the effects of the present invention. That is, the pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive containing an acrylic polymer, a rubber-based pressure-sensitive adhesive containing a rubber-based polymer, a silicone-based pressure-sensitive adhesive containing a silicone-based polymer, and a urethane-based pressure-sensitive adhesive containing a urethane polymer It contains at least one selected. In the following, an acrylic pressure-sensitive adhesive will be described in detail as a representative example.

<Acrylic adhesive>
An acrylic adhesive contains an acrylic polymer as a base polymer. The acrylic pressure-sensitive adhesive may contain a tackifying resin. The acrylic pressure-sensitive adhesive may contain a crosslinking agent.

When the acrylic pressure-sensitive adhesive contains an acrylic polymer, a tackifying resin, and a crosslinking agent, the content ratio of the total amount of the acrylic polymer, the tackifying resin, and the crosslinking agent to the total amount of the acrylic pressure-sensitive adhesive is It is preferably 95% by weight or more, more preferably 97% by weight or more, and still more preferably 99% by weight or more, in that the effects can be further developed.

(Acrylic polymer)
As the acrylic polymer, for example, a polymer of a monomer component which contains an alkyl (meth) acrylate as a main monomer and can further contain a submonomer having a copolymerizability with the main monomer is preferable. Here, the main monomer means a component that accounts for more than 50% by weight of the total monomer components.

As the alkyl (meth) acrylate, for example, a compound represented by the following formula (1) can be suitably used.
CH ₂ = C (R ¹ ) COOR ² (1)

Here, R ¹ in the above formula (1) is a hydrogen atom or a methyl group, and R ² is a chain alkyl group having 1 to 20 carbon atoms (hereinafter, such a range of the number of carbon atoms is “C1- 20)). From the viewpoint of storage elastic modulus of the pressure-sensitive adhesive layer, R ² is preferably a C 1-14 linear alkyl group, more preferably a C 2-10 linear alkyl group, and still more preferably C 4-8 It is a chain alkyl group. Here, the term "linear" is meant to include linear and branched.

Examples of alkyl (meth) acrylates in which R ² is a C1-20 linear alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate and n-butyl (Meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) Acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate , Nonadecyl (meth) acrylate, eicosyl (meth) acrylate and the like. These alkyl (meth) acrylates may be used alone or in combination of two or more.

Preferred examples of the alkyl (meth) acrylate include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) in that the effects of the present invention can be further developed.

The content ratio of the alkyl (meth) acrylate to the total monomer components used for the synthesis of the acrylic polymer is preferably 70% by weight or more, more preferably 85% by weight in that the effect of the present invention can be further developed. It is the above, More preferably, it is 90 weight% or more. The upper limit of the content ratio of the alkyl (meth) acrylate is preferably 99.5 wt% or less, more preferably 99 wt% or less. However, the acrylic polymer may be one obtained by polymerizing substantially only alkyl (meth) acrylate.

When R ² using the alkyl (meth) acrylate is a linear alkyl group of C4-8, alkyl R ² is a linear alkyl group of C4-8 among alkyl (meth) acrylates contained in the monomer components The proportion of (meth) acrylate is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 90% by weight or more, from the viewpoint of achieving the effects of the present invention. It is preferably 95% by weight or more, and most preferably 99% by weight to 100% by weight.

One embodiment of the acrylic polymer is an acrylic polymer in which 50% by weight or more of the total monomer components is n-butyl acrylate (BA). In this case, the content ratio of n-butyl acrylate (BA) in all the monomer components is preferably more than 50% by weight and not more than 100% by weight, more preferably 55, in that the effects of the present invention can be more developed. % To 95% by weight, more preferably 60% to 90% by weight, particularly preferably 63% to 85% by weight, and most preferably 65% to 80% by weight. The total monomer component may further contain 2-ethylhexyl acrylate (2EHA) in a proportion smaller than that of n-butyl acrylate (BA).

One embodiment of the acrylic polymer is an acrylic polymer in which less than 50% by weight of all monomer components are 2-ethylhexyl acrylate (2EHA). In this case, the content ratio of 2-ethylhexyl acrylate (2EHA) in all the monomer components is preferably more than 0% by weight and not more than 48% by weight, more preferably 5 in that the effects of the present invention can be more developed. % To 45% by weight, more preferably 10% to 43% by weight, particularly preferably 15% to 40% by weight, and most preferably 20% to 35% by weight. The total monomer component may further contain n-butyl acrylate (BA) in a proportion greater than 2-ethylhexyl acrylate (2EHA).

Other monomers may be copolymerized with the acrylic polymer as long as the effects of the present invention are not impaired. The other monomers can be used, for example, for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer, adjusting the adhesive performance, and the like. For example, as a monomer capable of improving the cohesive strength and heat resistance of the pressure-sensitive adhesive, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl esters, aromatic vinyl compounds and the like can be mentioned Is preferred. Specific examples of vinyl esters include, for example, vinyl acetate (VAc), vinyl propionate, vinyl laurate and the like, with preference given to vinyl acetate (VAc).

The “other monomer” may be only one kind or two or more kinds. The content ratio of the other monomers in the total monomer component is preferably 0.001 wt% to 40 wt%, more preferably 0.01 wt% to 40 wt%, still more preferably 0.1 wt% to It is 10% by weight, particularly preferably 0.5% by weight to 5% by weight, and most preferably 1% by weight to 3% by weight.

As other monomers that can introduce a functional group that can be a crosslinking point into an acrylic polymer, or that can contribute to the improvement of adhesion, for example, hydroxyl group (OH group) containing monomers, carboxy group containing monomers, acid anhydride group containing monomers, amides Group-containing monomers, amino group-containing monomers, imide group-containing monomers, epoxy group-containing monomers, (meth) acryloyl morpholine, vinyl ethers and the like can be mentioned.

Another embodiment of the acrylic polymer includes an acrylic polymer in which a carboxy group-containing monomer is copolymerized as the other monomer. Examples of carboxy group-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, etc. Can be mentioned. Among these, preferred are, as the carboxy group-containing monomer, acrylic acid (AA) and methacrylic acid (MAA) from the viewpoint of achieving the effects of the present invention, and acrylic acid (AA) is more preferable. is there.

When a carboxy group-containing monomer is employed as the other monomer, the content ratio of the other monomer in all the monomer components is preferably 0.1% by weight to 10% by weight in that the effect of the present invention can be further developed. More preferably, it is 0.2 wt% to 8 wt%, still more preferably 0.5 wt% to 5 wt%, particularly preferably 0.7 wt% to 4 wt%, most preferably 1 wt%. % To 3% by weight.

An acrylic polymer in which a hydroxyl group-containing monomer is copolymerized as another monomer is mentioned as one embodiment of an acrylic polymer. As a hydroxyl group containing monomer, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) A) hydroxyalkyl (meth) acrylates such as acrylates; polypropylene glycol mono (meth) acrylates; N-hydroxyethyl (meth) acrylamides; and the like. Among these, as the hydroxyl group-containing monomer, preferred is a hydroxyalkyl (meth) acrylate in which the alkyl group is a linear group having 2 to 4 carbon atoms, in that the effect of the present invention can be further expressed. Specifically, examples thereof include 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA), and more preferred is 4-hydroxybutyl acrylate (4HBA).

When a hydroxyl group-containing monomer is employed as the other monomer, the content ratio of the other monomer in all the monomer components is preferably 0.001% by weight to 10% by weight in that the effect of the present invention can be further developed. Preferably, it is 0.01 wt% to 5 wt%, more preferably 0.02 wt% to 2 wt%, particularly preferably 0.03 wt% to 1 wt%, most preferably 0.05 % By weight to 0.5% by weight.

The Tg of the base polymer may be, for example, −80 ° C. or higher in that the effect of the present invention can be further developed. The base polymer (preferably an acrylic polymer) is designed to have a Tg of preferably −15 ° C. or less, from the viewpoint of enhancing the deformability of the pressure-sensitive adhesive layer in the shear direction. In some embodiments, the Tg of the base polymer is, for example, preferably −25 ° C. or less, more preferably −40 ° C. or less, and still more preferably −50 ° C. or less. The Tg of the base polymer is, for example, designed to be preferably -70 ° C. or more (more preferably -65 ° C. or more, still more preferably -60 ° C. or more) from the viewpoint of enhancing the cohesion and shape recovery. It is done.

The Tg of the base polymer is calculated from the formula of Fox based on the Tg of the homopolymer (homopolymer) of each monomer constituting the base polymer and the weight fraction of the monomer (the copolymerization ratio on a weight basis). Refers to the required value. The Fox equation, as shown below, is a relationship between the Tg of the copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer.
1 / Tg = Σ (Wi / Tgi)

In the above Fox equation, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio by weight), Tgi is a homopolymer of monomer i Represents the glass transition temperature (unit: K) of As the Tg of the homopolymer, the value described in the known data is adopted.

As the Tg of the homopolymer, for example, specifically, the following values can be used.
2-ethylhexyl acrylate -70 ° C
n-Butyl acrylate -55 ° C
Acrylic acid 106 ° C
2-hydroxyethyl acrylate-15 ° C
4-hydroxybutyl acrylate -40 ° C

As for the Tg of homopolymers other than those exemplified above, the numerical values described in “Polymer Handbook” (Third Edition, John Wiley & Sons, Inc., 1989) can be used. When a plurality of numerical values are described in the above-mentioned "Polymer Handbook", the conventional value is adopted. For monomers that are not described in the above "Polymer Handbook", the catalog values of monomer manufacturing companies are adopted. As a Tg of a homopolymer of a monomer which is not described in the above-mentioned "Polymer Handbook" and for which a catalog value of a monomer manufacturing company is not provided, a value obtained by the measuring method described in JP-A-2007-51271 is used Do.

As a method of obtaining an acrylic polymer, for example, appropriately adopt various polymerization methods known as synthetic methods of acrylic polymers such as solution polymerization method, emulsion polymerization method, bulk polymerization method, suspension polymerization method and the like. Can. Among these polymerization methods, a solution polymerization method can be preferably used. As a monomer supply method at the time of performing solution polymerization, a batch preparation method, a continuous supply (dropping) method, a divisional supply (dropping) method or the like can be suitably adopted which supplies the entire amount of the monomer components at one time. The polymerization temperature can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc., preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and still more preferably 40 ° C. It is the above, Preferably it is 170 degrees C or less, More preferably, it is 160 degrees C or less, More preferably, it is 140 degrees C or less. As a method of obtaining an acrylic polymer, photopolymerization (typically performed in the presence of a photopolymerization initiator) performed by irradiating light such as UV or radiation such as β-ray or γ-ray is performed. Alternatively, active energy ray irradiation polymerization such as radiation polymerization may be employed.

As a solvent (polymerization solvent) used for solution polymerization, it can select suitably from arbitrary appropriate organic solvents. For example, aromatic compounds such as toluene (typically, aromatic hydrocarbons), acetates such as ethyl acetate, and aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane can be mentioned.

The initiator (polymerization initiator) used for polymerization can be appropriately selected from any appropriate polymerization initiator according to the type of polymerization method. The polymerization initiator may be only one type, or two or more types. Examples of such a polymerization initiator include azo polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN); persulfates such as potassium persulfate; benzoyl peroxide, hydrogen peroxide and the like Peroxide initiators; substituted ethane initiators such as phenyl-substituted ethane; aromatic carbonyl compounds; and the like. Other examples of polymerization initiators include redox initiators based on a combination of peroxide and reducing agent.

The amount of the polymerization initiator to be used is preferably 0.005 part by weight to 1 part by weight, more preferably 0.01 part by weight to 1 part by weight with respect to 100 parts by weight of all the monomer components.

The Mw of the acrylic polymer is preferably 10 × 10 ⁴ to 500 × 10 ⁴ , more preferably 10 × 10 ⁴ to 150 × 10 ⁴ , and still more preferably 20 × 10 ⁴ to 75 × 10 ⁴ And particularly preferably 35 × 10 ⁴ to 65 × 10 ⁴ . Here, Mw refers to a value in terms of standard polystyrene obtained by GPC (gel permeation chromatography). As the GPC apparatus, for example, a model name “HLC-8320 GPC” (column: TSKgel GMH-H (S), manufactured by Tosoh Corporation) can be used.

(Tackifying resin)
The acrylic pressure-sensitive adhesive may contain a tackifying resin in that the effect of the present invention can be further developed. As tackifying resin, for example, rosin-based tackifying resin, terpene-based tackifying resin, hydrocarbon-based tackifying resin, epoxy-based tackifying resin, polyamide-based tackifying resin, elastomer-based tackifying resin, phenol-based tackifying resin And ketone-based tackifying resins. The tackifying resin may be only one kind or two or more kinds.

The amount of tackifier resin used is preferably 5 parts by weight to 70 parts by weight, and more preferably 10 parts by weight to 60 parts by weight, with respect to 100 parts by weight of the base polymer in that the effects of the present invention can be exhibited more Parts, more preferably 15 parts by weight to 50 parts by weight, still more preferably 20 parts by weight to 45 parts by weight, particularly preferably 25 parts by weight to 40 parts by weight, and most preferably 25 parts by weight 35 parts by weight.

The tackifying resin preferably includes a tackifying resin TL having a softening point of less than 105 ° C. in that the effect of the present invention can be further developed. The tackifying resin TL can effectively contribute to the improvement of the deformability in the plane direction (shearing direction) of the pressure-sensitive adhesive layer. The softening point of the tackifying resin used as the tackifying resin TL is preferably 50 ° C. to 103 ° C., more preferably 60 ° C. to 100 ° C., and still more preferably from the viewpoint of obtaining a higher deformability improvement effect. C. to 95.degree. C., particularly preferably 70.degree. C. to 90.degree. C., most preferably 75.degree. C. to 85.degree.

The softening point of the tackifying resin is defined as a value measured based on the softening point test method (ring and ball method) defined in JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible at a low temperature, and it is carefully filled in a ring placed on a flat metal plate so that bubbles can not occur. After cooling, use a slightly heated knife to cut off the raised part from the plane containing the top of the ring. Next, the support (ring base) is placed in a glass container (heating bath) having a diameter of 85 mm or more and a height of 127 mm or more, and glycerin is poured to a depth of 90 mm or more. Next, immerse the steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample in glycerin so as not to contact each other, and keep the temperature of the glycerin at 20 ° C plus or minus 15 ° C for 15 minutes . Next, place a steel ball in the center of the surface of the sample in the ring and place it in place on the support. Next, the distance from the upper end of the ring to the glycerin surface is maintained at 50 mm, a thermometer is placed, and the center of the mercury bulb in the thermometer is positioned at the same height as the center of the ring to heat the container. The flame of the Bunsen burner used for heating is located halfway between the center and the edge of the bottom of the container to equalize the heating. The rate of increase of the bath temperature after reaching 40 ° C. after the start of heating should be 5.0 plus / minus 0.5 ° C./min. The temperature at which the sample gradually softens and flows out of the ring and finally contacts the bottom plate is read and taken as the softening point. Two or more samples of softening point are measured at the same time, and the average value is adopted.

The amount of tackifier resin TL used is preferably 5 parts by weight to 50 parts by weight, and more preferably 10 parts by weight to 100 parts by weight of the base polymer in terms of achieving the effects of the present invention. It is 45 parts by weight, more preferably 15 parts by weight to 40 parts by weight, particularly preferably 20 parts by weight to 35 parts by weight, and most preferably 25 parts by weight to 32 parts by weight.

Among the tackifying resins exemplified above, one or two or more types appropriately selected from those having a softening point of less than 105 ° C. can be adopted as the tackifying resin TL. The tackifying resin TL preferably comprises a rosin resin.

Examples of rosin-based resins that can be preferably adopted as the tackifying resin TL include rosin esters such as unmodified rosin esters and modified rosin esters. Examples of modified rosin esters include hydrogenated rosin esters.

The tackifying resin TL preferably contains a hydrogenated rosin ester in that the effect of the present invention can be further developed. As a hydrogenated rosin ester, the softening point is preferably less than 105 ° C., more preferably 50 ° C. to 100 ° C., still more preferably 60 ° C. to 90 ° C. in that the effect of the present invention can be exhibited more. C., particularly preferably 70.degree. C. to 85.degree. C., most preferably 75.degree. C. to 85.degree.

The tackifying resin TL may comprise a non-hydrogenated rosin ester. Here, the non-hydrogenated rosin ester is a concept that comprehensively refers to the above-described rosin esters other than the hydrogenated rosin ester. Non-hydrogenated rosin esters include unmodified rosin esters, disproportionated rosin esters, polymerized rosin esters, and the like.

As a non-hydrogenated rosin ester, the softening point is preferably less than 105 ° C., more preferably 50 ° C. to 100 ° C., still more preferably 60 ° C. to 90 ° C. in that the effect of the present invention can be more developed. ° C., particularly preferably 70 ° C. to 85 ° C., most preferably 75 ° C. to 85 ° C.

The tackifying resin TL may contain another tackifying resin in addition to the rosin resin. Among the tackifying resins exemplified above, one or two or more types appropriately selected from those having a softening point of less than 105 ° C. can be adopted as other tackifying resins. The tackifying resin TL may contain, for example, a rosin resin and a terpene resin.

The content ratio of the rosin-based resin in the entire tackifying resin TL is preferably more than 50% by weight, more preferably 55% by weight to 100% by weight in that the effect of the present invention can be further developed. Is 60% to 99% by weight, particularly preferably 65% to 97% by weight, and most preferably 75% to 97% by weight.

The tackifier resin includes, in combination, the tackifier resin TL and the tackifier resin TH having a softening point of 105 ° C. or higher (preferably 105 ° C. to 170 ° C.) in that the effect of the present invention can be further developed. Good.

Among the tackifying resins exemplified above, one or two or more types appropriately selected from those having a softening point of 105 ° C. or higher may be employed as the tackifying resin TH. The tackifying resin TH may include at least one selected from rosin-based tackifying resins (eg, rosin esters) and terpene-based tackifying resins (eg, terpene phenolic resin).

(Crosslinking agent)
The acrylic pressure-sensitive adhesive can contain a crosslinking agent. The crosslinking agent may be only one type, or two or more types. The use of the crosslinking agent can impart an appropriate cohesive force to the acrylic pressure-sensitive adhesive. The crosslinker can also help to control the offset distance and return distance in retention testing. An acrylic pressure-sensitive adhesive containing a crosslinking agent can be obtained, for example, by forming a pressure-sensitive adhesive layer using a pressure-sensitive adhesive composition containing the crosslinking agent. The crosslinking agent may be included in the acrylic pressure-sensitive adhesive in a form after the crosslinking reaction, a form before the crosslinking reaction, a form after the partial crosslinking reaction, an intermediate or composite form of these, and the like. The crosslinking agent is typically contained in the acrylic pressure-sensitive adhesive exclusively in the form after the crosslinking reaction.

The amount of the crosslinking agent used is preferably 0.005 parts by weight to 10 parts by weight, and more preferably 0.01 parts by weight, with respect to 100 parts by weight of the base polymer in that the effects of the present invention can be further developed. The amount is about 7 parts by weight, more preferably 0.05 parts by weight to 5 parts by weight, particularly preferably 0.1 parts by weight to 4 parts by weight, and most preferably 1 part by weight to 3 parts by weight.

As a crosslinking agent, for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, a silicone crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a silane crosslinking agent, an alkyl etherified melamine crosslinking agent, a metal chelate crosslinking agent And cross-linking agents such as peroxides, and the like, and from the viewpoint of achieving the effects of the present invention, an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent are preferable, and an isocyanate-based cross-linking agent is more preferable. .

As the isocyanate-based crosslinking agent, a compound having two or more isocyanate groups (including an isocyanate regenerated functional group in which an isocyanate group is temporarily protected by a blocking agent or quantification or the like) can be used. Examples of the isocyanate crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate; and the like.

More specifically, as the isocyanate-based crosslinking agent, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2 Aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (eg, Tosoh Corporation Trade name Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (for example, Tosoh Corp. trade name: Coronate HL) Isocyanate adducts such as isocyanurate of samethylene diisocyanate (eg, Tosoh Co., trade name: Coronate HX); trimethylolpropane adduct of xylylene diisocyanate (eg, Mitsui Chemical Co., trade name: Takenate D110N), Trimethylolpropane adduct of xylylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D120N), Isophorone diisocyanate, trimethylolpropane adduct (for example, Mitsui Chemicals, trade name: Takenate D140N), hexamethylene diisocyanate Trimethylolpropane adduct (eg Mitsui Chemicals, Inc., trade name: Takenate D160N); polyether polyisocyanate, polyester polyisocyanate, and various polycarbonates Adducts with; and the like; isocyanurate bond, biuret bond, polyisocyanates polyfunctionalized with allophanate bond. Among these, aromatic isocyanates and alicyclic isocyanates are preferable in that they can achieve both deformability and cohesion in a well-balanced manner.

The amount of the isocyanate-based crosslinking agent used is preferably 0.005 parts by weight to 10 parts by weight, and more preferably 0.01 parts by weight, with respect to 100 parts by weight of the base polymer in that the effects of the present invention can be exhibited more. Parts by weight to 7 parts by weight, more preferably 0.05 parts by weight to 5 parts by weight, particularly preferably 0.1 parts by weight to 4 parts by weight, most preferably 1 part by weight to 3 parts by weight is there.

When the monomer component constituting the acrylic polymer contains a hydroxyl group-containing monomer, the weight ratio of the isocyanate-based crosslinking agent / hydroxyl group-containing monomer is preferably more than 20 and less than 50 in that the effect of the present invention can be expressed more. More preferably, it is 22 to 45, more preferably 25 to 40, particularly preferably 27 to 40, and most preferably 30 to 35.

When the acrylic pressure-sensitive adhesive contains the tackifying resin TL having a softening point of 105 ° C. or less, the weight ratio of the tackifying resin TL / isocyanate-based crosslinking agent is preferably more than 2 in that the effect of the present invention can be expressed more. It is less than 15, more preferably 5 to 13, still more preferably 7 to 12, and particularly preferably 7 to 11.

As an epoxy type crosslinking agent, the polyfunctional epoxy compound which has an epoxy group two or more in 1 molecule can be used. Examples of epoxy crosslinking agents include N, N, N ', N'-tetraglycidyl-m-xylenediamine, diglycidyl aniline, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, penta Erythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl Ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, two epoxy groups in the molecule The epoxy resin etc. which have the above are mentioned. As a commercial item of an epoxy-type crosslinking agent, the brand name "Tetraded C" by "Mitsubishi Gas Chemical Company", "Tetrad X" etc. are mentioned, for example.

The amount of the epoxy-based crosslinking agent used is preferably 0.005 parts by weight to 10 parts by weight, and more preferably 0.01 parts by weight, with respect to 100 parts by weight of the base polymer in that the effects of the present invention can be further developed. Parts by weight to 5 parts by weight, more preferably 0.015 parts by weight to 1 part by weight, still more preferably 0.015 parts by weight to 0.5 parts by weight, particularly preferably 0.015 parts by weight to It is 0.3 parts by weight, most preferably 0.15 to 0.3 parts by weight.

(Other ingredients)
The acrylic pressure-sensitive adhesive is, if necessary, an adhesive such as a leveling agent, a crosslinking aid, a plasticizer, a softener, a filler, an antistatic agent, an antiaging agent, an ultraviolet absorber, an antioxidant, a light stabilizer, etc. Various additives common in the field of agents may be contained. With regard to such various additives, conventionally known ones can be used by a conventional method.

«« Applications »»
The pressure-sensitive adhesive tape of the present invention is excellent in unevenness followability. Taking advantage of this feature, it can be preferably used in a mode of being stuck to a member having a movable bending portion.

Hereinafter, the present invention will be more specifically described by way of examples and comparative examples. However, the present invention is not at all limited thereto. In the following description, "parts" and "%" are by weight unless otherwise specified.

<Dimensional change rate>
The adhesive tape was cut into a strip of width 20 mm to prepare a test sample. About this measurement sample, the initial distance between chucks is set to 20 mm using a tensile tester (made by Shimadzu Corp., name: Autograph AG-IS type) in an environment of 23 ° C. and 50% RH, and measurement is performed. The sample was pulled at a tensile speed of 300 mm / min in the longitudinal direction so as to have a deformation of 100% (that is, twice the original length), and the dimensional change was calculated according to the following equation. As shown in FIG. 3, L is the length in the longitudinal direction (tension direction) after tension, and D is the length in the transverse direction (direction perpendicular to the tension direction) after tension.
Dimension change rate = {(D−D0) / D0} / {(L−L0) / L0}

<Young's modulus>
Young's modulus is calculated based on the results of 20% elongation test conducted under the following conditions. The same method is adopted for Examples and Comparative Examples described later.
[20% extension test]
Sample shape: 10 mm wide strip Initial chuck distance: 20 mm
Tension speed: 300 mm / min Tension deformation: 20%
Procedure: Under the measurement environment of 23 ° C. and 50% RH, the above sample is clamped in the chuck of the tensile tester such that the above-mentioned initial chuck distance is 20 mm. Then, Young's modulus was calculated from the results of displacement and stress obtained by stretching (20% elongation) the sample until the distance between chucks became 24 mm at the above-mentioned tensile speed.
In addition, although the tension direction in the said test is not specifically limited, It is preferable to make it correspond with the longitudinal direction of an adhesive sheet. As a tensile tester, product name "Autograph AG-10G tensile tester" manufactured by Shimadzu Corporation can be used.

<Maximum stress>
The maximum stress is calculated based on the results of a 100% elongation test conducted under the following conditions. The same method is adopted for Examples and Comparative Examples described later.
[100% extension test]
Sample shape: 10 mm wide strip Initial chuck distance: 20 mm
Tension speed: 300 mm / min Tension deformation: 100%
Procedure: Under the measurement environment of 23 ° C. and 50% RH, the above sample is clamped in the chuck of the tensile tester such that the above-mentioned initial chuck distance is 20 mm. Then, the maximum stress (tensile stress) (MPa) was measured when the sample was stretched (100% elongation) until the distance between chucks was 40 mm at the above-mentioned tensile speed, and this was taken as the maximum stress.

<Stress ratio (B / A)>
The ratio of the tensile stress (A) immediately after 100% elongation in the 100% elongation test to the tensile stress after 1 s while maintaining the 100% elongation was taken as a stress ratio (B / A).

<Adhesiveness>
The adhesion refers to the 180 degree peel strength (180 degree peel adhesion) to the stainless steel plate. The 180 degree peel strength is a size of 20 mm in width and 100 mm in length after sticking a single-sided adhesive tape (trade name "No. 31 B" manufactured by Nitto Denko Corp., total thickness 50 μm) on the back of the adhesive sheet. In the environment of 23 ° C. and 50% RH, the adhesive surface of the measurement sample is crimped by causing one reciprocation of a 2 kg roll to the surface of a stainless steel plate (SUS304BA plate) under an environment of 23 ° C. and 50% RH. After leaving this for 30 minutes in the same environment, using a universal tensile compression tester, according to JIS Z 0237: 2000, under the conditions of 300 mm / min tensile speed and 180 ° peel angle, the peel strength (N / N 20 mm) was measured. As a universal tensile and compression tester, for example, a “tensile compression tester, TG-1 kN” manufactured by Minebea Co., Ltd. can be used.

<Break resistance evaluation>
The adhesive tape was cut into a strip of 10 mm in width to prepare a test sample. In an environment of 23 ° C. and 50% RH, the release liner is peeled off from the test sample, and the exposed adhesive surface is made 10 mm wide and 20 mm long on a PET film (S10, 200 μm thick) as an adherend. A 2 kg roller was reciprocated once in the pasting area of (1) and crimped. After leaving the test sample attached to the adherend in this way for 5 minutes in the same environment, the PET film is bent 180 degrees in the direction perpendicular to the longitudinal direction of the tape, and then opposite to the direction in which it was bent. It was again folded 180 degrees in the direction (ie, it was folded 180 degrees and then folded 180 degrees). At least two of these are generated, with no visible color change such as float (void), wrinkles, whitening, etc. being visible between the tape and PET at the twice-folded point. The thing was x.

Example 1
In a reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet pipe and condenser, 30 parts of 2-ethylhexyl acrylate (2EHA) as a monomer component, 70 parts of n-butyl acrylate (BA), acrylic acid (AA) 2 parts, and 0.1 parts of 4-hydroxybutyl acrylate (4HBA), 0.08 parts of 2,2'-azobisisobutyro nitrile (AIBN) as a polymerization initiator, and as a polymerization solvent Toluene: 150 parts were charged, and solution polymerization was carried out at 65 ° C. for 8 hours to obtain a toluene solution of an acrylic polymer (A). The weight average molecular weight of this acrylic polymer (A) was 440,000.
Tackifying resin TA (Halima Chemicals, Inc., hydrogenated rosin glycerin ester, trade name "Harritac SE10", softening point 75 to 85 ° C.): 30 relative to 100 parts of the acrylic polymer (A) contained in the above toluene solution A pressure-sensitive adhesive composition (A) was prepared by adding 2.7 parts of an isocyanate-based crosslinking agent (Tosoh, trade name "Corronate L").
Two commercially available release liners (manufactured by Sumika Kako Paper Co., Ltd., trade name "SLB-80W3D") were prepared. The pressure-sensitive adhesive composition (A) was applied to one surface (release surface) of each release liner so that the thickness after drying was 50 μm, and dried at 100 ° C. for 5 minutes. Thus, a 50 μm-thick pressure-sensitive adhesive layer (a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer) composed of the acrylic pressure-sensitive adhesive (A) corresponding to the pressure-sensitive adhesive composition (A) Each was formed on the release surface of a release liner.
A caprolactam-based (ester-based) polyurethane resin film (A) (100% modulus = 6.5 MPa) having a thickness of 100 μm was prepared as a base material layer. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the two release liners were attached to the first surface and the second surface of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer. The resulting structure was passed once through an 80 ° C. laminator (0.3 MPa, speed 0.5 m / min) and then aged in an oven at 50 ° C. for 1 day. Thus, an adhesive tape (1) was obtained.

Example 2
The adhesive composition was prepared in the same manner as in the preparation of the pressure-sensitive adhesive composition (A) in Example 1, except that the amount of the isocyanate-based crosslinking agent (Tosoh Co., Ltd., trade name "Coronato L") was changed to 1.8 parts. The product (B) was prepared.
Two commercially available release liners (manufactured by Sumika Kako Paper Co., Ltd., trade name "SLB-80W3D") were prepared. The pressure-sensitive adhesive composition (B) was applied to one surface (release surface) of each release liner so that the thickness after drying was 20 μm, and dried at 100 ° C. for 5 minutes. Thus, the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer and second pressure-sensitive adhesive layer) having a thickness of 20 μm, which is composed of the acrylic pressure-sensitive adhesive (B) corresponding to the pressure-sensitive adhesive composition (B) Each was formed on the release surface of a release liner.
A caprolactam-based (ester-based) polyurethane resin film (A) (100% modulus = 6.5 MPa) having a thickness of 60 μm was prepared as a base material layer. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the two release liners were attached to the first surface and the second surface of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer. The resulting structure was passed once through an 80 ° C. laminator (0.3 MPa, speed 0.5 m / min) and then aged in an oven at 50 ° C. for 1 day. Thus, an adhesive tape (2) was obtained.

[Example 3]
The procedure of Example 1 was repeated to prepare a pressure-sensitive adhesive composition (A).
Two commercially available release liners (manufactured by Sumika Kako Paper Co., Ltd., trade name "SLB-80W3D") were prepared. The pressure-sensitive adhesive composition (A) was applied to one surface (release surface) of each release liner so that the thickness after drying was 10 μm, and dried at 100 ° C. for 5 minutes. Thus, a 10 μm thick pressure-sensitive adhesive layer (a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer) composed of the acrylic pressure-sensitive adhesive (A) corresponding to the pressure-sensitive adhesive composition (A) Each was formed on the release surface of a release liner.
As a base material layer, an ether-based polyurethane resin film (B) (100% modulus = 5.6 MPa) having a thickness of 30 μm was prepared. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the two release liners were attached to the first surface and the second surface of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer. The resulting structure was passed once through an 80 ° C. laminator (0.3 MPa, speed 0.5 m / min) and then aged in an oven at 50 ° C. for 1 day. Thus, an adhesive tape (3) was obtained.

Example 4
The procedure of Example 1 was repeated to prepare a pressure-sensitive adhesive composition (A).
Two commercially available release liners (manufactured by Sumika Kako Paper Co., Ltd., trade name "SLB-80W3D") were prepared. The pressure-sensitive adhesive composition (A) was applied to one surface (release surface) of each release liner so that the thickness after drying was 10 μm, and dried at 100 ° C. for 5 minutes. Thus, a 10 μm thick pressure-sensitive adhesive layer (a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer) composed of the acrylic pressure-sensitive adhesive (A) corresponding to the pressure-sensitive adhesive composition (A) Each was formed on the release surface of a release liner.
As a base material layer, an ether-based polyurethane resin film (C) (100% modulus = 2.3 MPa) having a thickness of 30 μm was prepared. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the two release liners were attached to the first surface and the second surface of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer. The resulting structure was passed once through an 80 ° C. laminator (0.3 MPa, speed 0.5 m / min) and then aged in an oven at 50 ° C. for 1 day. Thus, an adhesive tape (4) was obtained.

Comparative Example 1
The procedure of Example 1 was repeated to prepare a pressure-sensitive adhesive composition (A).
Two commercially available release liners (manufactured by Sumika Kako Paper Co., Ltd., trade name "SLB-80W3D") were prepared. The pressure-sensitive adhesive composition (A) was applied to one surface (release surface) of each release liner so that the thickness after drying was 19 μm, and dried at 100 ° C. for 5 minutes. Thus, a pressure-sensitive adhesive layer (a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer) having a thickness of 19 μm constituted of the acrylic pressure-sensitive adhesive (A) corresponding to the pressure-sensitive adhesive composition (A) Each was formed on the release surface of a release liner.
As a base material layer, a PET base material (D) (made by Toray, trade name "Lumirror S10") with a thickness of 12 μm was prepared. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the two release liners were attached to the first surface and the second surface of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer. The resulting structure was passed once through an 80 ° C. laminator (0.3 MPa, speed 0.5 m / min) and then aged in an oven at 50 ° C. for 1 day. Thus, an adhesive tape (C1) was obtained.

The pressure-sensitive adhesive tape of the present invention is excellent in unevenness followability, and thus can be preferably used, for example, as a pressure-sensitive adhesive tape to be attached to a member having a movable bending portion.

1000 adhesive tape 100 base layer 200 adhesive layer 200 a adhesive layer 200 b adhesive layer

Claims

A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one side of a substrate layer,
The dimensional change rate at 23 ° C. is 0.20 to 0.39,
Adhesive tape.
The pressure-sensitive adhesive tape according to claim 1, wherein the Young's modulus at 23 ° C is 0.2 MPa to 25 MPa.
The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the maximum stress at 100% tension at a tension rate of 300 mm / min at 23 ° C is 0.1 MPa to 6.0 MPa.
The ratio (B / A) of stress B after holding the 100% tensile state for 1 second to the stress A applied immediately after 100% tensile at a tensile speed of 300 mm / min at 23 ° C. is 0.7 to 1. The adhesive tape in any one of Claim 1 to 3 which is 0.
The pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein the adhesive strength of the pressure-sensitive adhesive layer to a SUS plate at a tensile speed of 300 mm / min and 180 degree peel at 23C is 5 N / 20 mm or more.
The pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein the total thickness d is 1 μm to 500 μm.
The adhesive tape according to claim 6, wherein a ratio (d1 / d) of the total thickness d1 of the pressure-sensitive adhesive layer to the total thickness d is 0.7 or less.
The pressure-sensitive adhesive tape according to any one of claims 1 to 7, wherein the base material layer contains at least one polar functional group-containing polymer selected from condensation polymers and polyaddition polymers.
The pressure-sensitive adhesive tape according to claim 8, wherein the polar functional group-containing polymer is at least one selected from polyamide, polyurethane and polyurea.
The adhesive tape according to claim 8 or 9, wherein the polar functional group-containing polymer has at least one selected from an ether bond and an ester bond.
The adhesive tape in any one of Claim 1 to 10 in which the said adhesive layer contains at least 1 sort (s) chosen from an acrylic adhesive, a rubber adhesive, a silicone adhesive, and a urethane adhesive.