TW201546229A - Substrate-free double-sided adhesive sheet - Google Patents

Abstract

The present invention is to provide a substrate-free double-sided adhesive sheet with improved cutting processability and, even after long-term storage, capable of inhibiting the overflow of the adhesive layer and improving the adhesion workability. This invention provides a substrate-free double-sided adhesive sheet 1 with the two sides of adhesive layer 2 protected by a release liner 3 and a release liner 4. A dry edge portion 5 without an adhesive layer is provided at two ends of the width direction of the substrate-free double-sided adhesive sheet, wherein the length at the width direction of each dry edge portion is more than 20 times the thickness of the adhesive layer.

Description

Substrate-free double-sided adhesive sheet

The present invention relates to a substrateless double-sided adhesive sheet.

In the case where the two members are bonded to each other in the prior art, it is excellent in workability, workability, adhesion and the like, and is widely used as an adhesive on both sides of the substrate to be a support. The double-sided adhesive sheet of the layer. In particular, in recent years, the above-mentioned double-sided adhesive sheet has been used for fixing small electronic parts such as mobile phones or the like.

For a small electronic component that is light, small, and thin, or a peripheral device thereof, a thin film of a double-sided adhesive sheet is required. According to such a request, there is proposed a double-sided adhesive sheet which is a double-sided adhesive sheet which does not have a substrate as a support and which has only an adhesive layer (see Patent Documents 1 and 2).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-348236

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-169281

The substrate-free double-sided adhesive sheet which has existed before has no basis for being a support Therefore, the adhesive layer is easily deformed, and is particularly remarkable in the case where the thickness of the adhesive layer is thinned. In this case, it is considered that when the substrate is a support, the deformation of the adhesive layer is suppressed by the substrate.

Therefore, when the non-substrate double-sided adhesive sheet is cut into a specific width, the adhesive adheres to the cutting blade due to the deformation of the adhesive layer, and the adhesive is removed by adhering the adhesive to the cut surface. The shape of the face is deformed. Further, in order to remove the adhesive adhering to the cutting blade, it is necessary to temporarily interrupt the cutting process and perform the cleaning of the cutting blade, and the cutting workability is remarkably lowered. In particular, it is more remarkable when the non-substrate double-sided adhesive sheet is cut into finer. On the other hand, it is understood that if the peeling liner is peeled off after long-term storage of the substrate-free double-sided adhesive sheet which has been subjected to the cutting process, unintentional separation occurs, and workability is remarkably lowered. The reason for this is that the adhesive layer overflows from the side of the double-sided adhesive sheet without the substrate, and the adhesive is adhered to the side of the release liner.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a substrate-free double-sided adhesive sheet which is improved in cutting workability and which suppresses overflow of an adhesive layer even after long-term storage and improves adhesion.

The inventors of the present invention have diligently studied to solve the above problems, and as a result, have found that focusing on the structure of the substrate-free double-sided adhesive tape, a dry edge portion having no adhesive layer is provided on both ends of the substrate-free double-sided adhesive tape. With attention to the relationship between the dry edge portion and the thickness of the adhesive layer, by providing a specific dry edge portion, it is possible to provide an improvement in cutting workability when a substrate-free double-sided adhesive sheet is obtained, and even if it is stored for a long period of time It can also suppress the overflow of the adhesive layer, thereby improving the adhesive-free substrate-free double-sided adhesive sheet.

That is, the present invention relates to the invention disclosed below.

[1] A substrate-free double-sided adhesive sheet which is protected by a release liner on both sides of the adhesive layer, and has no adhesive at both ends of the width of the substrate-free double-sided adhesive sheet. The dry edge of the layer, the length of each of the above-mentioned dry edges is the thickness of the adhesive layer More than 20 times the degree.

[2] In a further preferred embodiment, the elastic storage modulus of the adhesive layer at 25 ° C is 10 ⁷ Pa or less.

[3] In a further preferred embodiment, the elastic storage modulus of the adhesive layer at 80 ° C is 10 ⁶ Pa or less.

[4] As a further preferred embodiment, the adhesive constituting the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive.

[5] In a further preferred embodiment, the acrylic adhesive is an acrylic acid obtained by polymerizing a monomer component having an alkyl (meth)acrylate having an alkyl group having 4 to 20 carbon atoms as a main monomer. Is a polymer.

[6] In a further preferred embodiment, the length of the adhesive layer in the width direction is 1 mm to 30 mm.

[7] In a further preferred embodiment, the thickness of the adhesive layer is from 1 μm to 100 μm.

[8] In a further preferred embodiment, the length of each of the dry side portions in the width direction is 1 mm or more.

Since the substrateless double-sided adhesive sheet of the present invention has the above-described configuration, it is possible to prevent the adhesive from adhering to the cut blade when cutting the substrate-free double-sided adhesive sheet of the present invention having a specific width. Improve cutting processability. Moreover, since the above-described configuration is provided, even if the substrate-free double-sided adhesive sheet is stored for a long period of time, the overflow of the adhesive layer can be suppressed. In addition, the cooperation with the industry has also improved.

1‧‧‧Uncoated double-sided adhesive sheet

2‧‧‧Adhesive layer

3‧‧‧Release liner

4‧‧‧Release liner

5‧‧‧dry side

6‧‧‧Drying Department

101‧‧‧ Direction of travel

102‧‧‧width direction

201‧‧‧The length of the width of the dry edge

202‧‧‧ Length of the width of the dry edge

203‧‧‧The length of the width of the dryer section

301‧‧‧The length of the adhesive layer in the width direction

401‧‧‧The length of the width direction of the substrate-free double-sided adhesive sheet

Fig. 1 is a schematic view (top view) showing an example of a substrate-free double-sided adhesive sheet of the present invention.

Fig. 2 is a schematic cross-sectional view showing the width direction of the substrate-free double-sided adhesive sheet of the present invention.

Figure 3 is a schematic cross-sectional view showing the traveling direction of the substrate-free double-sided adhesive sheet of the present invention.

Fig. 4 is a schematic view (top view) showing another example of the substrateless double-sided adhesive sheet of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as needed.

Fig. 1 is a schematic view (top view) showing an example of a substrate-free double-sided adhesive sheet of the present invention. The both sides of the adhesive layer 2 in the substrateless double-sided adhesive sheet 1 are protected by the release liner 3 and the release liner 4. Here, the longitudinal direction of the substrate-free double-sided adhesive sheet is referred to as the traveling direction 101, and the direction perpendicular to the traveling direction is referred to as the width direction 102. The dry side portion 5 having no adhesive layer is provided at both ends of the width-free direction 102 of the substrate-free double-sided adhesive sheet 1.

Fig. 2 is a schematic cross-sectional view (a schematic cross-sectional view in the width direction) as seen from the traveling direction of the substrate-free double-sided adhesive sheet of the present invention. The double-sided adhesive sheet 2 of the substrate-free double-sided adhesive sheet 1 is protected on both sides by a release liner 3 and a release liner 4, and has dry edges 5 having no adhesive layer at both ends.

Fig. 3 is a schematic cross-sectional view (a schematic cross-sectional view of the traveling direction) as seen from the width direction of the substrate-free double-sided adhesive sheet of the present invention. The both sides of the adhesive layer 2 in the substrateless double-sided adhesive sheet 1 are protected by the release liner 3 and the release liner 4.

[No substrate double-sided adhesive sheet]

The substrateless double-sided adhesive sheet 1 of the present invention has a structure of an adhesive layer 2. Further, the adhesive layer 2 may have one or more adhesive layers. Here, "without a substrate" means that there is no substrate (especially a substrate film).

The substrateless double-sided adhesive sheet 1 of the present invention has a structure in which both sides of the adhesive layer 2 are protected by a release liner 3 and a release liner 4.

The shape of the substrate-free double-sided adhesive sheet 1 of the present invention may be a sheet shape, and may be, for example, a shape wound in a roll shape or a single plate shape.

The substrateless double-sided adhesive sheet 1 of the present invention has no width at both ends of the width direction 102 The dry edge portion 5 of the adhesive layer is provided. Further, the lengths 201 and 202 of the dry side portion 5 in the width direction are each 20 times or more the thickness of the adhesive layer 2. By thus having the dry edge portion 5 as described above at both ends of the substrate-free double-sided adhesive sheet 1, the substrate-free double-sided adhesive sheet is cut into a specific width to obtain a substrate-free double-sided When the sheet 1 is adhered, adhesion of the adhesive to the cutting blade can be suppressed, and deformation of the shape of the cut surface can be remarkably suppressed. Further, since the adhesion of the adhesive to the cutting blade can be suppressed, it is not necessary to temporarily stop the cutting process in order to clean the blade, and the cutting workability is remarkably improved. Further, it is possible to suppress the overflow of the adhesive layer in the case where the substrate-free double-sided adhesive sheet is stored for a long period of time, and it is possible to suppress adhesion of the adhesive to the side surface of the release liner or the like, and to improve workability. In particular, it is preferable to perform the cutting process so that the length 401 of the width direction 102 of the substrate-free double-sided adhesive sheet 1 is shorter and thinner. This is because the adhesive is more likely to adhere to the cutting blade when the length 401 of the width direction 102 of the double-sided adhesive sheet 1 is cut to be shorter and thinner. The both sides of the non-substrate double-sided adhesive sheet 1 have the dry side portion 5 as described above, and the deformation of the shape of the cut surface is further suppressed, and the workability and the workability are also improved.

The preferred range of the lengths 201, 202 of the width direction 102 of the dry side portion 5 having no adhesive layer at both ends of the substrateless double-sided adhesive sheet 1 of the present invention is relative to the adhesive layer 2 The thickness is 30 times or more, and more preferably 50 times or more, more preferably 80 times or more, and most preferably 95 times or more. The upper limit of the lengths 201 and 202 in the width direction of the dry side portion 5 is not particularly limited, but is preferably 500 times or less, more preferably 300 times or less, still more preferably 200 times or less, and most preferably 150 times or less. By setting such a range, when the substrate-free double-sided adhesive sheet 1 processed to a specific width is cut, the adhesion of the adhesive to the cutting blade can be further suppressed, and the deformation of the shape of the cut surface can be further suppressed. . Further, since the adhesion of the adhesive to the cutting blade can be further suppressed, it is not necessary to temporarily stop the cutting process in order to clean the blade, and the cutting workability can be further improved. Further, it is possible to further suppress the overflow of the adhesive layer in the case where the substrate-free double-sided adhesive sheet is stored for a long period of time, and it is possible to further suppress adhesion of the adhesive to the side surface of the release liner or the like, and to further improve workability.

The lengths 201 and 202 of the width direction 102 of the dry side portion 5 having no adhesive layer at both ends of the substrate-free double-sided adhesive sheet 1 of the present invention may be the same or different. The lengths 201 and 202 of the dry side portion 5 in the width direction are preferably 1 mm or more from the viewpoint of cutting workability and workability. More preferably, it is 1 mm to 10 mm, further preferably 1 mm to 8 mm, and most preferably 2 mm to 5 mm. Moreover, the ratio of the length of each of the lengths 201 and 202 in the width direction of the dry side portion 5 (the length 201 of the width direction of the dry side portion 5: dry side portion) from the viewpoint of cutting workability and workability The length 202 of the width direction of 5 is preferably 1:10 to 10:1, more preferably 1:5 to 5:1, further preferably 1:2 to 2:1, and particularly preferably 1:1. Moreover, the ratio of the length of the width of the dry side portion 5 which does not have the adhesive layer to the both ends of the non-substrate double-sided adhesive sheet 1 from the viewpoint of cutting workability or workability (total The ratio) is preferably from 4% to 90%, more preferably from 10% to 90%, even more preferably from 10% to 80%, relative to the length of the entire substrate-free double-sided adhesive sheet 1 in the width direction. Good is 20%~80%, especially 50%~80%.

The length 301 of the width direction 102 of the adhesive layer of the substrate-free double-sided adhesive sheet 1 of the present invention is preferably from 1 mm to 30 mm, more preferably from 1 mm to 10 mm, still more preferably from 1 mm to 5 mm. By setting it as such a range, cutting workability and workability can be improved, and the adhesiveness with respect to a to-be-attached body can be improved.

The length 401 of the width direction 102 of the substrate-free double-sided adhesive sheet 1 of the present invention is preferably from 3 mm to 50 mm, more preferably from 3 mm to 30 mm, from the viewpoint of the adhesion of the adherend. Good for 5mm~15mm.

Fig. 4 is a schematic view (top view) showing another example of the substrateless double-sided adhesive sheet of the present invention. The substrateless double-sided adhesive sheet 1 has a plurality of adhesive layers 2, and the both sides thereof are protected by a release liner 3 and a release liner 4. The dry side portion 5 having no adhesive layer is provided at both ends of the width-free direction 102 of the substrate-free double-sided adhesive sheet 1. Further, a drying portion 6 having no adhesive layer is provided between the plurality of adhesive layers 2.

In another embodiment of the substrateless double-sided adhesive sheet of the present invention, there are a plurality of The adhesive layer 2 is protected by the release liner 3 and the release liner 4, and has a dry edge portion 5 having no adhesive layer at both ends of the width-free direction 102 of the substrate-free double-sided adhesive sheet 1 Further, a drying portion 6 having no adhesive layer is provided between the plurality of adhesive layers 2. By having the drying portion 6 having no adhesive layer between the plurality of adhesive layers 2, the non-substrate double-sided adhesive sheet 1 can be stored for a long period of time, and the adhesion of the adhesive layer 2 can be further suppressed. . Moreover, even when external pressure is applied to the substrate-free double-sided adhesive sheet 1, the overflow of the adhesive layer 2 can be suppressed. Then, when the non-substrate double-sided adhesive sheet 1 is bonded to the adherend, the release liner is also easily peeled off, and the unintentional separation of the adhesive layer 2 can be suppressed, and the adherend can be further improved. Stick to cooperation. In particular, when the shape of the substrate-free double-sided adhesive sheet 1 is wound into a roll shape, the adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 is liable to overflow due to external pressure, but by With the configuration described above, the overflow of the adhesive layer 2 can be suppressed.

The number of the adhesive layer 2 of the present invention is not particularly limited as long as it is set according to various uses of the substrate-free double-sided adhesive sheet 1, and the substrate-free double-sided adhesive sheet 1 is bonded to the bonded body. From the viewpoint of sex, it is preferably two or three.

The length 203 of the width direction 102 of the drying portion 6 having no adhesive layer of the present invention is preferably from 0.5 mm to 10 mm, more preferably from 0.5 mm to 8 mm, still more preferably from 0.5 mm to 5 mm. When the substrate-free double-sided adhesive sheet 1 is stored for a long period of time, the overflow of the adhesive layer 2 can be further suppressed, and even if the substrate-free double-sided adhesive sheet is adhered to 1 When the external pressure is applied, the overflow of the adhesive layer 2 can also be suppressed. Further, when the non-substrate double-sided adhesive sheet 1 is bonded to the adherend, the release liner is further easily peeled off, and the unintentional separation of the adhesive layer 2 can be suppressed, and the attachment to the adherend can be further improved. Cooperative nature. Further, the length 203 of the width direction 102 of the drying portion 6 not having the adhesive layer and the length of the width direction 102 of the dry side portion 5 having no adhesive layer on both ends of the substrate-free double-sided adhesive sheet 1 201 and 202 may be the same or different.

From the viewpoint of operability, the length 203 of the width direction 102 of the drying portion 6 having no adhesive layer of the present invention is preferably 20 times or more the thickness of the adhesive layer 2. More preferably 30 The ratio is more than 50 times, more preferably 50 times or more, and most preferably 95 times or more. The upper limit of the length 203 of the width direction 102 of the drying unit 6 is not particularly limited, but is preferably 500 times or less, more preferably 300 times or less, still more preferably 200 times or less, and most preferably 150 times or less.

From the viewpoint of cutting workability, workability, and workability, the width of the dry side portion 5 having no adhesive layer is provided at both ends of the substrate-free double-sided adhesive sheet 1 of the present invention. The ratio of the length to the total length of the drying portion 6 having no adhesive layer in the width direction is preferably 4% to 90% with respect to the length of the entire substrate-free double-sided adhesive sheet 1 in the width direction. It is 20% to 80%, more preferably 50% to 80%.

[Adhesive layer]

When the substrate-free double-sided adhesive sheet 1 of the present invention is bonded to the adherend, the adhesion to the adherend is important, but it is understood that the adhesive layer is suppressed from the viewpoint of cutting workability and the like. In the case where the adhesive itself is deformed to a small extent (for example, an adhesive having a high modulus of elasticity), the adhesion to the adherend is lowered, and the workability is remarkably lowered. According to this case, the shear storage elastic modulus G' of the adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 of the present invention at 25 ° C is preferably 10 ⁷ Pa or less, more preferably 10 ⁴ to 10 ⁷ Pa, further preferably 10 ⁴ to 10 ⁶ Pa, most preferably 10 ⁴ to 10 ⁵ Pa. By setting it as such a range, the adhesiveness of the non-substrate double-sided adhesive sheet 1 to the to-be-attached body can be improved. The shear storage elastic modulus G' of the above adhesive layer 2 may be composed of an adhesive constituting the adhesive layer (for example, a copolymerization of an acrylic polymer in the case of an acrylic adhesive) or a molecular weight , cross-linking agents and other additives to adjust. Further, the shear storage elastic modulus G' of the present invention is a value measured by the following method.

<Measurement of Shear Storage Elastic Modulus G'>

A measurement sample (adhesive layer or adhesive layer) was prepared to a thickness of 1.5 mm to 2 mm, and then punched with a punch having a diameter of 7.9 mm to prepare a sample for measurement. A viscoelastic spectrometer (trade name "ARES", manufactured by Rheometric Scientific Co., Ltd.) was used, and the chuck pressure was set to 100 g, the shear was set to a frequency of 1 Hz, and the temperature was measured at a temperature increase rate of 5 ° C / min. set. The apparatus was a stainless steel 8 mm parallel plate (manufactured by TA Instruments, model 708.0157).

The adhesive layer 2 of the substrateless double-sided adhesive sheet 1 of the present invention preferably has a shear storage elastic modulus G' of 10 ⁶ Pa or less at 80 °C. More preferably, it is 10 ⁴ to 10 ⁶ Pa, further preferably 10 ⁴ to 10 ⁶ Pa, and most preferably 10 ⁴ to 10 ⁵ Pa. By setting it as such a range, the adhesiveness of the non-substrate double-sided adhesive sheet 1 to the to-be-attached body can be improved. The shear storage elastic modulus G' of the above adhesive layer 2 may be composed of an adhesive constituting the adhesive layer (for example, a copolymerization of an acrylic polymer in the case of an acrylic adhesive) or a molecular weight , cross-linking agents and other additives to adjust. Further, the shear storage elastic modulus G' of the present invention is a value measured by the above method.

The thickness of the adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 of the present invention is preferably from 1 μm to 100 μm, more preferably from 5 μm to 80 μm, still more preferably from 10 μm to 50 μm. By setting it as such a range, it is possible to further suppress the overflow of the adhesive layer in the case where the substrate-free double-sided adhesive sheet is stored for a long period of time, and it is possible to further suppress adhesion of the adhesive to the side surface of the release liner or the like, thereby further improving the operation. Sex.

The adhesive (base polymer) constituting the adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 of the present invention is not particularly limited, and examples thereof include an acrylic adhesive, a rubber adhesive, and a polyfluorene. Oxygen adhesives, etc. These may be used alone or in combination of two or more.

The content of the adhesive constituting the adhesive layer 2 used in the present invention is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 90% by mass or more based on the mass (100% by mass) of the adhesive layer 2. 95% by mass or more. The upper limit of the content of the adhesive constituting the adhesive layer 2 is preferably 100% by mass or less, more preferably 98% by mass or less, still more preferably 97% by mass or less.

The gel fraction of the adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 of the present invention is not particularly limited, and is, for example, preferably 20% by mass to 90% by mass, more preferably 20% by mass to 60% by mass. Further, it is preferably 40% by mass to 50% by mass. By setting this range, it is possible to improve the non-base The double-sided adhesive sheet of the material is bonded to the adherend. Further, in the case where the adhesive constituting the adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 is a rubber-based adhesive, the gel fraction of the adhesive layer 2 is preferably from 0% by mass to 20% by mass. It is more preferably 0% by mass to 10% by mass, still more preferably 0% by mass to 5% by mass. By setting it as such a range, the adhesiveness of the non-substrate double-sided adhesive sheet 1 to the to-be-attached body can be improved. Further, the gel fraction of the present invention is a value measured by the following method.

<Measurement of gel fraction>

The gel fraction was obtained by wrapping a measurement sample of the weight W1 on a porous sheet made of a tetrafluoroethylene resin, immersing it in ethyl acetate at room temperature for one week, and drying the measurement sample. The weight W2 of the ethyl acetate insoluble component was measured, and W1 and W2 were substituted into the following formula: gel fraction [%] = W2 / W1 × 100. As the porous sheet made of the above-mentioned tetrafluoroethylene resin, the product name "NITOFLON (registered trademark)" manufactured by Nitto Denko Corporation can be used.

The acrylic adhesive used in the present invention is preferably a polymer (acrylic polymer) obtained by polymerizing a monomer component containing an alkyl (meth)acrylate as a main monomer.

The main monomer used in the present invention is not particularly limited, and examples thereof include n-butyl (meth)acrylate, isobutyl (meth)acrylate, and second butyl (meth)acrylate. Base) tert-butyl acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, ( 2-ethylhexyl methacrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylate Isodecyl ester, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, (a) Pentadecyl acrylate, cetyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, hexadecane (meth) acrylate A (meth)acrylic acid alkyl ester having a linear or branched alkyl group having an alkyl group having 4 to 20 carbon atoms, such as a group ester or an amyl (meth)acrylate. Furthermore, in this specification, The term "(meth)acrylic" means "acrylic acid" and/or "methacrylic acid". In the above, from the viewpoint of adhesion or adhesion of the adherend, an alkyl (meth)acrylate having an alkyl group having a carbon number of 5 to 12 is preferred, and more preferably an acrylic acid 2- Ethylhexyl ester (2EHA).

The content of the main monomer used in the present invention is preferably 50 to 100% by weight, and more preferably 70 to 100% by weight based on the total amount of the monomer component (100% by weight) constituting the acrylic pressure-sensitive adhesive.

The acrylic pressure-sensitive adhesive of the present invention may contain other monomer components copolymerizable with the above (meth)acrylic acid alkyl ester, if necessary, in order to modify the cohesive force and crosslinkability. Examples of such a monomer component include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and carboxyethyl acrylate; An acid anhydride group-containing monomer such as dianhydride or itaconic anhydride; a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate or hydroxybutyl (meth)acrylate; Acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-methylol a acetamide monomer such as propane (meth) acrylamide or the like (N-substituted or unsubstituted); a vinyl ester monomer such as vinyl acetate or vinyl propionate; styrene, α-methyl styrene, etc. Styrene monomer; vinyl ether monomer such as vinyl methyl ether or vinyl ether; cyanoacrylate monomer such as acrylonitrile or methacrylonitrile; epoxy group such as glycidyl (meth)acrylate Acrylic monomer; olefin or diene monomer such as ethylene, propylene, isoprene, butadiene, isobutylene; aminoethyl (meth)acrylate, N,N-di(meth)acrylate Amino group-containing monomer (substituted or unsubstituted) amine group-containing monomer; (meth)acrylic acid methoxyethyl ester, (methyl) (A) alkoxyalkyl (meth)acrylate monomer such as ethoxyethyl acrylate; N-vinylpyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinyl Piperidone, N-vinylpyrimidine, N-vinylpiperidone N-vinylpyrene , N-vinylpyrrole, N-vinylimidazole, N-vinyl Oxazole, N-vinyl a monomer having a ring containing a nitrogen atom such as a porphyrin or an N-vinyl caprolactam; a decylamine N-vinylcarboxylate; a styrenesulfonic acid, an allylsulfonic acid, or a (meth)acrylamide a sulfonic acid group-containing monomer such as a sulfonic acid or a sulfopropyl (meth)acrylate; a phosphate group-containing monomer such as 2-hydroxyethyl acrylate; N-cyclohexylmethyleneimine, N- Isobutyleneimine monomer such as isopropyl maleimide, N-lauryl maleimide, N-phenyl maleimide, etc.; N-methyl Ikonium imine, N-ethyl Ikonium imine, N-butyl Ikonide, N-octyl Icinoimine, N-2-ethylhexylkkonium imine, N - Isopreneimine monomer such as cyclohexyl ikonide imine, N-lauryl Icinoimide; N-(methyl) propylene oxymethylene amber succinimide, N-(A Butyldiamine, such as acrylonitrile-6-oxyhexamethylenebutaneimine, N-(methyl)propenyl-8-oxyoctamethylenebutylimine Monomer; glycol acrylate monomer such as polyethylene glycol (meth) acrylate or polypropylene glycol (meth) acrylate; tetrahydrofurfuryl (meth) acrylate a monomer having a hetero ring containing an oxygen atom; an acrylate monomer containing a fluorine atom such as a fluorine (meth) acrylate; and an acrylate monomer containing a ruthenium atom such as a polyfluorene (meth) acrylate Hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, Pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, multifunctional epoxy acrylate, polyfunctional A polyfunctional monomer such as a polyester acrylate, a polyfunctional polyacrylic acid urethane, divinylbenzene, butyl di(meth)acrylate, or hexyl di(meth)acrylate. These monomer components may be used alone or in combination of two or more. Among the above monomer components, from the viewpoint of improving cohesive strength and crosslinkability, a hydroxyl group-containing or carboxyl group-containing monomer is preferred, and 2-hydroxyethyl (meth)acrylate or hydroxybutyl (meth)acrylate is more preferred. Or acrylic (AA). The content of the hydroxyl group-containing monomer is preferably less than 10% by weight, more preferably 5% by weight or less, even more preferably 2% by weight or less based on the total amount of the monomer component (100% by weight) constituting the acrylic pressure-sensitive adhesive. . The content of the carboxyl group-containing monomer is preferably less than 20% by weight, and more preferably 5% by weight or less based on the total amount of the monomer component (100% by weight) constituting the acrylic pressure-sensitive adhesive.

The acrylic adhesive of the present invention can be prepared by polymerizing the above monomer components, and has no special The solution polymerization method, the emulsion polymerization method, the bulk polymerization method, the polymerization method by active energy ray irradiation (active energy ray polymerization method), and the like are exemplified. Among them, in terms of transparency, water resistance, cost, and the like, a solution polymerization method, an active energy ray polymerization method, and a solution polymerization method are more preferable.

When the solution is polymerized, various usual solvents can be used. Examples of such a solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; and cyclohexane and methylcyclohexane. An alicyclic hydrocarbon; an organic solvent such as a ketone such as methyl ethyl ketone or methyl isobutyl ketone. The solvent may be used singly or in combination of two or more.

In the polymerization of the acrylic adhesive of the present invention, a polymerization initiator can be used. The polymerization initiator is not particularly limited, and can be appropriately selected and used, and examples thereof include 2,2'-azobisisobutyronitrile and 2,2'-azobis(4-methoxy-2). , 4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1 '-Azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-A Azo-based polymerization initiators such as methyl propyl propionate; benzamidine peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, diisobutyl peroxide Peroxidation of propylbenzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclododecane An oil-soluble polymerization initiator such as an organic polymerization initiator. These may be used singly or in combination of two or more. The amount of the polymerization initiator to be used is not particularly limited, and may be any range that can be used as a polymerization initiator.

Further, the acrylic pressure-sensitive adhesive may be crosslinked by adding a crosslinking agent. Examples of the crosslinking agent include an epoxy compound, an isocyanate compound, a metal chelate compound, a metal alkoxide, a metal salt, an amine compound, a ruthenium compound, and an aldehyde compound, and these may be based on an acrylic acid system. The functional group contained in the adhesive is suitably used for selection. Among these, from the viewpoint of imparting cohesiveness to the acrylic pressure-sensitive adhesive, an epoxy compound or an isocyanate compound is preferable. The amount of the crosslinking agent used, for example, relative to the above propylene The acid-based adhesive is preferably used in an amount of from 0.01 to 10 parts by weight, preferably from 0.05 to 5 parts by weight, per 100 parts by weight.

Specific examples of the isocyanate compound used in the present invention include lower aliphatic polyisocyanates such as butyl diisocyanate and hexamethylene diisocyanate; cyclopentylene diisocyanate and cyclohexyl diisocyanate; An alicyclic isocyanate such as isophorone diisocyanate; an aromatic isocyanate such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate or benzodimethyl diisocyanate; trimethylolpropane /Toluene diisocyanate trimer adduct (trade name "Coronate L", manufactured by Tosoh Corporation), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate" HL"), an isocyanate adduct such as an isocyanurate body of hexamethylene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate HX").

Specific examples of the epoxy compound used in the present invention include N, N, N', N'-tetraglycidyl metaxylylenediamine, diglycidylaniline, and 1,3-double. (N,N-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd.) , product name "Epolight 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500NP"), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 70P"), polyethylene glycol diglycidyl ether (manufactured by Nippon Oil Co., Ltd., trade name "EPIOL E-400") Polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "EPIOL P-200"), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX, trade name "DENACOL EX-611"), glycerol polyglycidol Ether (manufactured by Nagase ChemteX, trade name "DENACOL EX-314"), pentaerythritol polycondensation Oleic ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX, trade name "DENACOL EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl Ester, diglycidyl phthalate, three (2- Hydroxyethyl) isocyanuric acid triglycidyl ester, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and the like.

Examples of the rubber-based adhesive used in the present invention include natural rubber-based adhesives; isoprene rubber, polyisobutylene rubber, butyl rubber, ethylene-propylene rubber, styrene-butadiene rubber, and styrene. -isoprene rubber, styrene-ethylene-propylene-styrene rubber, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene- Synthetic rubber such as ethylene-butylene-styrene block copolymer, styrene-ethylene-propylene-styrene block copolymer, styrene-ethylene-propylene block copolymer, recycled rubber, or modified bodies thereof Adhesive (including block copolymer, and random copolymer). These may be used alone or in combination of two or more. Among them, a butyl rubber or a polyisobutylene rubber is preferred from the viewpoint of the adhesion of the adherend.

The weight average molecular weight of the acrylic pressure-sensitive adhesive used in the present invention is not particularly limited, but is preferably from 10,000 to 5,000,000, more preferably from 100,000 to 2,000,000, still more preferably from 200,000 to 1,500,000. The above weight average molecular weight can be obtained, for example, by gel permeation chromatography and converted to standard polystyrene.

The rubber-based adhesive (for example, butyl rubber or polyisobutylene rubber) used in the present invention preferably has the following molecular weight distribution. Preferably, the rubber-based adhesive having a molecular weight of 300,000 or more and 5,000,000 or less (preferably having a molecular weight of 300,000 to 4.8 million, particularly preferably having a molecular weight of 300,000 to 4.5 million) is 50% by mass to 95% by mass, more preferably 52% by mass. The mass % to 95% by mass, further preferably 55% by mass to 95% by mass, more preferably MW of 10,000 or more and less than 300,000 (preferably having a molecular weight of 10,000 to 280,000, particularly preferably a molecular weight of 10,000). The content of the rubber-based adhesive of 250,000) is 5% by mass or more and less than 50% by mass, more preferably 5% by mass to 48% by mass, and particularly preferably 5% by mass to 45% by mass. Further, the content of the rubber-based adhesive is based on the mass (100% by mass) of the adhesive layer. By using a rubber-based adhesive having such a molecular weight distribution, the adhesion to the adherend can be improved. The molecular weight of the rubber-based adhesive of the present invention is measured by the following method.

<Measurement of molecular weight distribution>

After the measurement sample was taken by selection, a solution of THF (tetrahydrofuran, tetrahydrofuran) was prepared and allowed to stand overnight. The solution was filtered through a 0.45 μm membrane filter, and the filtrate was subjected to gel permeation chromatography (GPC measurement) (HLC-8120GPC, manufactured by Tosoh Corporation) to calculate the molecular weight ranges of the GPC differential molecular weight distribution curve in terms of standard polystyrene. The area ratio is taken as the mass fraction (% by mass).

Measuring condition

Column: TSKgel

Column size: 6.0mmI.D.×150mm

Dissolution: THF

Flow rate: 0.6mL/min

Detector: RI

Column temperature: 40 ° C

Injection volume: 20μL

As the rubber-based pressure-sensitive adhesive having the above molecular weight distribution, one type of rubber-based pressure-sensitive adhesive may be used alone, or two or more types of rubber-based pressure-sensitive adhesives having different weight average molecular weights may be used in combination. From the viewpoint of improving the workability of the cutting property or the overflow of the adhesive layer and the adhesion to the adherend, it is preferred to use a combination of two or more kinds of rubber-based adhesives having different weight average molecular weights. When a combination of two or more kinds of adhesives having different weight average molecular weights is used, for example, it is preferred to have a weight average molecular weight of 300,000 to 1.5 million (preferably 400,000 to 1.1 million, particularly preferably 450,000 to 100). 10,000) high molecular weight adhesive, and a low molecular weight adhesive with a weight average molecular weight of 10,000 or more and less than 300,000 (preferably 10,000 to 200,000, especially preferably 10,000 to 100,000) 95/5~65 /35 (preferably 90/10~68/32, especially preferably 85/15~70/30) [The former/the latter (mass ratio)] is mixed and used.

Examples of the polyoxynoxy adhesive which can be used in the present invention include a polyoxyxylene rubber or a polyoxyxylene resin containing an organic polysiloxane as a main component, or an oxygen peroxide added thereto. A crosslinking agent such as an alkane crosslinking agent or a peroxide crosslinking agent is crosslinked or polymerized.

In the adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 of the present invention, in addition to the above-mentioned adhesive (base polymer), other components (for example, a suitable adhesion-imparting agent or a plasticizer (for example, A trimellitate-based plasticizer, a pyromellie-based plasticizer, or the like, a filler, an antioxidant, and the like may be used alone or in combination of two or more.

As the adhesion-imparting agent used in the present invention, any appropriate adhesion-imparting agent can be used. As the adhesion-imparting agent, for example, an adhesive-imparting resin can be used. Specific examples of the adhesion-imparting resin include a rosin-based adhesion-imparting resin (rosin-based resin), a rosin-based resin, a petroleum-based resin, a terpene-based resin, and a ketone-based resin. One type or two or more types may be used. Use in combination. The amount of the adhesion-imparting agent added is preferably 5 parts by mass to 50 parts by mass, more preferably 10 parts by mass to 50 parts by mass, per 100 parts by mass of the base polymer.

Examples of the rosin-based resin used in the present invention include rosin gum, wood rosin, and tall rosin. As the rosin-based resin, a stabilized rosin obtained by disproportionating or hydrogenating any appropriate rosin can be used. Further, as the rosin-based resin, a polymerized rosin which is a polymer of any appropriate rosin (typically a dimer) may be used, and any appropriate rosin may be modified (for example, by an unsaturated acid) Modification of the modified rosin obtained.

The rosin-derived resin to be used in the present invention may, for example, be an esterified product of the above rosin-based resin, a phenol-modified product of a rosin-based resin, or an esterified product of a phenol-modified rosin-based resin.

Examples of the petroleum-based resin used in the present invention include an aliphatic petroleum resin, an aromatic petroleum resin, a copolymerized petroleum resin, an alicyclic petroleum resin, and the like.

Examples of the terpene-based resin used in the present invention include an α-pinene resin, a β-pinene resin, an aromatic modified terpene resin, and a phenol resin.

Examples of the ketone resin used in the present invention include ketones (for example, fats). A ketone resin obtained by condensing an aliphatic ketone or an alicyclic ketone with formaldehyde.

[release liner]

The double-sided adhesive layer 2 of the substrate-free double-sided adhesive sheet 1 of the present invention has a double layer protected by a release liner 3 and a release liner 4. The release liner used in the present invention is not particularly limited, and for example, a plastic film or paper surface-treated with a release agent such as polyfluorene-based, long-chain alkyl, fluorine or molybdenum sulfide can be used. a substrate having a release layer; comprising polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chlorofluoroethylene-vinylidene fluoride copolymer A low-adhesive substrate of a fluorine-based polymer; a low-adhesive substrate containing a nonpolar polymer such as an olefin resin (for example, polyethylene or polypropylene). Among them, from the viewpoint of the adhesion of the substrate-free double-sided adhesive sheet 1, a plastic film or a low-adhesive substrate which is surface-treated by a release agent is preferred.

The thickness of the release liner used in the present invention is not particularly limited, and is preferably from 20 μm to 200 μm, more preferably from 25 μm to 150 μm, even more preferably 25 μm from the viewpoint of adhesion to the adherend. 100 μm.

The peeling force in the 180° peeling test of the release liner used in the present invention with respect to the adhesive layer 2 is not particularly limited, and is preferably 0.03 from the viewpoint of the adhesion of the adherend. N/50mm~1N/50mm, more preferably 0.03~0.6N/50mm. Further, the peeling force was measured by a 180° peeling test in accordance with JIS Z 0237:2009, and the measurement conditions were in an environment of 23° C. and 50% RH, a peeling angle of 180°, and a stretching speed of 300 mm/min. Further, the peeling force of each of the release liners provided on both sides of the adhesive layer 2 is preferably poor, and more specifically, preferably has a difference of 0.05 to 0.90 N/50 mm. By making the peeling force of the release liner provided on both sides of the adhesive layer 2 poor, the unintended separation of the adhesive layer 2 can be suppressed, and the adhesion to the adherend can be further improved.

Further, in FIGS. 1 to 4, the double-sided layer of the adhesive layer 2 is protected by two separate release liners (release liner 3 and release liner 4), but the substrate-free double of the present invention The surface-adhesive sheet is not limited to this form. For example, the substrateless double-sided adhesive sheet of the present invention In addition, the adhesive layer may be one form of a release liner which is a release surface on both sides, and is wound in a form of a roll (rolled body). In this case, the both sides of the adhesive layer are in a form protected by one release liner.

[Method for manufacturing non-substrate double-sided adhesive sheet]

The substrateless double-sided adhesive sheet 1 of the present invention can be produced by various known methods. For example, a plurality of stripe-shaped adhesive layers are formed by performing stripe coating or pattern coating on a release liner, and the release liner is bonded. Thereafter, the obtained adhesive sheet of the adhesive sheet is cut into a specific width or the like. Various known methods can be used for the cutting process, and examples thereof include a method of cutting by cutting a blade, and the like.

As the method of forming the above adhesive layer, any appropriate coating method can be employed. For example, it can be dried after coating to form an adhesive layer. Examples of the coating method include a coating method using, for example, a multi-coater, a die coater, a gravure coater, and an applicator. Examples of the drying method include natural drying, heat drying, and the like. The heating temperature in the case of performing heat drying can be set to any appropriate temperature depending on the characteristics of the substance to be dried.

The substrate-free double-sided adhesive sheet 1 of the present invention is not particularly limited, and for example, an electrochemical device such as an electronic device, an electronic device, an electrolytic capacitor, or a non-aqueous secondary battery (particularly, a lithium ion secondary battery) can be used. It is preferably used for the purpose of fixing the constituent members used inside.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by the examples. The evaluation methods of the examples are as follows. Further, in the examples, "parts" and "%" are quality standards unless otherwise specified.

Example 1

2-ethylhexyl acrylate/acrylic acid (mass ratio: 95 parts by mass/5 parts by mass) as a constituent monomer of an acrylic copolymer (weight average molecular weight: 1,000,000), 100 parts by mass, isocyanide 3 parts by mass of an acid ester-based crosslinking agent (trade name "Coronate L", manufactured by Tosoh Corporation) and 100 parts by mass of toluene were mixed to prepare a composition (A1) for forming an adhesive layer.

The obtained adhesive layer-forming composition (A1) was applied to a release liner such that the width of the adhesive layer was 2 mm and the distance between the adhesive layers was 6 mm (trade name "Cerapeel MDAR", Toray Advanced Film A release-treated surface of a thickness of 38 μm was produced by the company to form an adhesive layer having a thickness of 30 μm. A release liner (trade name "Diafoil MRF38", manufactured by Mitsubishi Plastics Co., Ltd., thickness: 38 μm) was attached to the formed adhesive layer to obtain a substrate-free double-sided adhesive sheet (B1). Then, the cutting blade (trade name "NT Spare Blade DISPENSER A", manufactured by NT) was cut so that the width of the adhesive layer was 2 mm, and the both ends had a dry edge portion and the width of each of the adhesive layers was 3 mm. A substrate-free double-sided adhesive sheet (C1) having dry edges at both ends is obtained.

Example 2

80 parts by mass of polyisobutylene rubber (trade name "Oppanol B80", manufactured by BASF Japan Co., Ltd.), 20 parts by mass of polyisobutylene rubber (trade name "Oppanol B12SFN", manufactured by BASF Japan), and 100 parts by mass of toluene. The composition for forming an adhesive layer (A2) was prepared by mixing.

A substrate-free double-sided adhesive sheet (C2) having dry edges at both ends was obtained in the same manner as in Example 1 except that the obtained adhesive layer-forming composition (A2) was used.

Example 3

2-ethylhexyl acrylate/ethyl acrylate/methyl methacrylate/2-hydroxyethyl acrylate (mass ratio: 40 parts by mass/60 parts by mass/5 parts by mass/4 parts by mass) as a constituent monomer 100 parts by mass of an acrylic copolymer (weight average molecular weight: 400,000), 2 parts by mass of an isocyanate-based crosslinking agent (trade name "Coronate L", manufactured by Tosoh Corporation), and dioctyltin dilaurate as a crosslinking accelerator (Product name "EMBILIZER OL-1", manufactured by Tokyo Fine Chemical Co., Ltd.) 0.05 parts by mass and 100 parts by mass of toluene were mixed to prepare a composition (A3) for forming an adhesive layer.

A substrate-free double-sided adhesive sheet (C3) having dry edges at both ends was obtained in the same manner as in Example 1 except that the obtained adhesive layer-forming composition (A3) was used.

Example 4

The adhesive layer-forming composition (A1) was applied to a release liner (trade name "Cerapeel MDAR", manufactured by Toray Advanced Film Co., Ltd.) in such a manner that the width of the adhesive layer was 2 mm and the interval between the adhesive layers was 6 mm. The release treated surface having a thickness of 38 μm was formed into an adhesive layer having a thickness of 100 μm. A release liner (trade name "Diafoil MRF38", manufactured by Mitsubishi Plastics Co., Ltd., thickness: 38 μm) was attached to the formed adhesive layer to obtain a substrate-free double-sided adhesive sheet (B4). Then, the cutting blade (trade name "NT Spare Blade DISPENSER A", manufactured by NT) was cut so that the width of the adhesive layer was 2 mm, and the both ends had a dry edge portion and the width of each of the adhesive layers was 3 mm. A substrate-free double-sided adhesive sheet (C4) having dry edges at both ends was obtained.

Comparative example 1

The adhesive layer-forming composition (A1) was applied to a release-treated surface of a release liner (trade name "Cerapeel MDAR", manufactured by Toray Advanced Film Co., Ltd., thickness: 38 μm) over the entire width direction to form an adhesive having a thickness of 30 μm. Floor. A release liner (trade name "Diafoil MRF38", manufactured by Mitsubishi Plastics Co., Ltd., thickness: 38 μm) was attached to the formed adhesive layer to obtain a substrate-free double-sided adhesive sheet (C5).

Comparative example 2

A substrate-free double-sided adhesive sheet (C6) was obtained in the same manner as in Comparative Example 1, except that the composition (A2) for forming an adhesive layer was used.

Comparative example 3

A substrate-free double-sided adhesive sheet (C7) was obtained in the same manner as in Comparative Example 1, except that the composition (A3) for forming an adhesive layer was used.

With respect to the substrate-free double-sided adhesive sheet obtained in the examples and the comparative examples, the shear storage elastic modulus, the cutting workability, the overflow amount of the adhesive layer, and the fit were evaluated by the following methods. Workability.

(1) Weight average molecular weight

The measurement of the weight average molecular weight of the acrylic copolymer used in the compositions (A1) and (A3) for forming an adhesive layer was carried out by the method described below.

[weight average molecular weight]

The measurement was carried out by a gel permeation chromatography (GPC) method. More specifically, the product name "HLC-8120GPC" (manufactured by Tosoh Corporation) can be used as a GPC measuring device, and the weight average molecular weight in terms of polystyrene can be measured under the following GPC measurement conditions.

(GPC measurement conditions)

Sample concentration: 0.2% by weight (tetrahydrofuran solution)

Sample injection amount: 10 μL

Dissolved solution: tetrahydrofuran (THF)

Flow rate (flow rate): 0.6mL/min

V column temperature (measuring temperature): 40 ° C

Pipe column: trade name "TSKgelSuperHM-H/H4000/H3000/H2000 (manufactured by Tosoh Corporation)

Detector: Differential Refractometer (RI)

(2) Shear storage elastic modulus

The adhesive layer-forming compositions (A1) to (A3) were applied to a release-treated surface of a release liner (trade name "Cerapeel MDAR", manufactured by Toray Advanced Film Co., Ltd., thickness: 38 μm) throughout the entire width direction. A release liner (trade name "Diafoil MRF38", manufactured by Mitsubishi Plastics Co., Ltd., thickness: 38 μm) was used to prepare an adhesive layer. The obtained adhesive was laminated to a thickness of 1.5 mm to 2 mm, and punched with a punch having a diameter of 7.9 mm to prepare a sample for measurement. A viscoelastic spectrometer (trade name "ARES", manufactured by Rheometric Scientific Co., Ltd.) was used, and the chuck pressure was set to 100 g, the shear was set to a frequency of 1 Hz, and the measurement was performed at a temperature increase rate of 5 ° C / min. The device is made of stainless steel 8mm flat Line plate (manufactured by TA Instruments, model 708.0157).

(3) Cutting processability

With respect to Examples 1 to 4, the contamination of the cutting blade for cutting was obtained by visual observation of the substrate-free double-sided adhesive sheets (C1) to (C4). Further, the observation of the cut surface of the cut sample (the substrate-free double-sided adhesive sheet) was visually observed. In addition, in the comparative examples 1 to 3, the non-substrate double-sided adhesive sheets (C5) to (C7) were cut into 5 mm using a cutting blade (trade name "NT Spare Blade DISPENSER A", manufactured by NT). The width was visually observed to be contaminant to the cutting blade at a 50 cm cut. Further, the observation of the cut surface of the cut sample was visually observed. The adhesion of the adhesive layer to the cutting blade and the observation of the cut surface of the sample were evaluated according to the following criteria.

[Contamination of the cutting blade]

○: There is no attachment on the cutting blade, and no defect of the adhesive layer is observed.

△: There is no deposit on the cut surface, and some defects of the adhesive layer are visible.

×: visible deposits on the cut surface

[Observation of the cut surface of the sample]

○: The shape of the cut surface is good.

△: a case where the shape of the cut surface is partially rough

×: The shape of the cut surface is rough

[Overview]

In the observation of the contamination of the cutting blade and the cut surface of the sample, it is assumed to be ○, and the other is set to ×.

(4) The amount of adhesive layer overflow

For Examples 1 to 4, a substrate-free double-sided adhesive sheet (C1) to (C4) having dry edges at both ends was used as a sample, and for Comparative Examples 1 to 3, a substrate-free double-sided adhesive sheet was used ( C5)~(C7) As a sample, place the sample in the center of the slide, and place a slide of the same shape on it, using a hot press (trade name "TP701-B HEAT SEAL TESTER", Tester Industrial (manufacturing)) Heating and pressurization were carried out at 50 ° C for 1 minute and at a pressure of 0.1 MPa. Thereafter, the distance between the apexes of the adhesive layer overflowing from both ends of the sample was measured by a projector, and the maximum length was defined as the amount of overflow of the adhesive layer.

(5) Sticking cooperation

The substrateless double-sided adhesive sheets (C1) to (C7) obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were used as samples. Two pieces of a 5 mm thick SUS430BA plate were fixed in a staggered manner to prepare a adherend having a step of 5 mm. The sample was bonded to the adherend without bulging, and was set to an initial state. After 30 minutes in an environment of 25 ° C × 50% RH, the state of the gap between the sample and the adherend was observed. In the case of no gap, it is set to ○, and when the gap is less than 1 mm, it is ○, and when the gap is 1 mm or more and less than 2 mm, it is Δ, and when the gap is 2 mm or more, it is set to ×.

The above evaluation results are summarized and shown in the following table.

As is clear from Table 1, the non-substrate double-sided adhesive sheets having the dry edges of Examples 1 to 4 can be cut by a dry edge portion having no adhesive layer, as compared with the comparative example. Significantly improved, can also inhibit the overflow of the adhesive layer. Moreover, the followability to the adherend can be improved, and the cooperation property can be improved.

The specific examples of the present invention have been described in detail above, but these are merely examples and are not intended to limit the scope of the claims. The technology described in the patent application scope includes various changes and modifications of the specific examples described above.

Claims (8)

A non-substrate double-sided adhesive sheet, which is protected by a release liner on both sides of the adhesive layer, and has no adhesive layer at both ends of the width of the substrate-free double-sided adhesive sheet In the side portion, the length in the width direction of each of the dry side portions is 20 times or more the thickness of the adhesive layer. The substrate-free double-sided adhesive sheet of claim 1, wherein the adhesive layer has a shear storage elastic modulus of 10 ⁷ Pa or less at 25 ° C. The substrate-free double-sided adhesive sheet according to claim 1 or 2, wherein the adhesive layer has a shear storage elastic modulus of 10 ⁶ Pa or less at 80 ° C. The substrate-free double-sided adhesive sheet according to claim 1 or 2, wherein the adhesive constituting the adhesive layer is an acrylic adhesive. The substrate-free double-sided adhesive sheet according to claim 4, wherein the acrylic adhesive is a monomer component having a (meth)acrylic acid alkyl ester having an alkyl group having 4 to 20 carbon atoms as a main monomer. The obtained acrylic polymer was polymerized. The substrate-free double-sided adhesive sheet according to claim 1 or 2, wherein the length of the adhesive layer in the width direction is 1 mm to 30 mm. The substrate-free double-sided adhesive sheet according to claim 1 or 2, wherein the thickness of the adhesive layer is from 1 μm to 100 μm. The substrate-free double-sided adhesive sheet according to claim 1 or 2, wherein each of the dry side portions has a length in the width direction of 1 mm or more.