JP2008050471A - Adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet enabling easy peeling of a release film and preventing undesirable adhesion of the adhesive layer to a release film. <P>SOLUTION: The pressure-sensitive adhesive sheet 1 includes a release film 3 laminated to at least one surface of a pressure-sensitive adhesive layer 4 composed of an adhesive or a pressure-sensitive adhesive agent. A cut line 2 is formed along the circumference of the release film 3 to enable the separate peeling of the outer side 2a and the inner side 2b of the cut line 2 from the pressure-sensitive adhesive layer 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive sheet used for bonding windows of automobiles, railway vehicles, ships, buildings, mechanical devices, etc., and display panels of flat-type image devices.

  A flat panel used for a liquid crystal television or a plasma television is formed by laminating optical films such as a polarizing film, a retardation film, an optical compensation film, and a brightness enhancement film. Recently, a pressure-sensitive adhesive sheet made of a transparent adhesive or pressure-sensitive adhesive has been used for laminating these optical films. As this type of pressure-sensitive adhesive sheet, for example, a pressure-sensitive adhesive sheet in which a release film is laminated on both sides of a pressure-sensitive adhesive layer made of a transparent pressure-sensitive adhesive is disclosed, and this pressure-sensitive adhesive sheet is continuously bonded to an optical film or the like. In addition, it is convenient because it can be cut out to a required size and then bonded to an optical film or the like (see Patent Document 1 below).

JP 2001-234129 A

However, as shown in FIG. 16, the conventional pressure-sensitive adhesive sheet as described above is bonded to the end surfaces of the release film 101 and the pressure-sensitive adhesive layer 102 by the adhesive or pressure-sensitive adhesive 102a that protrudes from the pressure-sensitive adhesive layer 102, thereby releasing the mold. It was sometimes difficult to lift the film 101.
Further, when the release film 101 on one side is peeled off, as shown in FIG. 17, the adhesive layer 102 is pulled by the release film 101 on one side and peels off from the release film 103 on the other side. ”Occurred and the adhesive sheet was wasted.

  In view of the above-described problems, the present invention is intended to provide a pressure-sensitive adhesive sheet that can easily lift up a release film and preferably can prevent crying separation.

  The present invention provides a pressure-sensitive adhesive sheet having a structure in which a release film is laminated on at least one surface side of an adhesive layer formed of an adhesive or a pressure-sensitive adhesive, and forms a score line along the peripheral edge of the release film, Provided is a pressure-sensitive adhesive sheet having a configuration in which an outer side and an inner side of a score line can be separately separated from a pressure-sensitive adhesive layer.

  In the pressure-sensitive adhesive sheet, since the pressure-sensitive adhesive does not easily protrude onto the cut line, the release film can be easily lifted using the cut line as a peeling start point, and the release films on the inner side and the outer side of the cut line can be easily peeled off.

  The present invention relates to a pressure-sensitive adhesive sheet having a structure in which a release film is laminated on both sides of an adhesive layer formed of an adhesive or a pressure-sensitive adhesive, and a score line along the peripheral edge of the release film on one side or both sides. And a release film on one side of the pressure-sensitive adhesive layer formed of an adhesive or pressure-sensitive adhesive, characterized in that the outer portion and the inner portion of the score line can be separately peeled from the pressure-sensitive adhesive layer In an optical member having a configuration in which an optical film is laminated on the other surface side, a score line is formed along the peripheral edge of the release film, and the outer side and the inner side of the score line are separated from the adhesive layer separately. An optical member characterized by a possible configuration is also provided.

  By peeling the inner part from the cut line, it is possible to peel the release film from the inside to the outside, and therefore, it is possible to peel it without lifting up the adhesive layer together. Moreover, since the outer portion is formed narrow along the peripheral portion, the adhesive area with the adhesive layer is small, and it can be peeled off with a small peeling force, so that the release film does not roll up the adhesive layer together Can be peeled off. For this reason, this invention becomes an adhesive sheet in which crying separation does not occur.

Furthermore, the present invention provides an adhesive sheet having a configuration in which a release film is laminated on both sides of an adhesive layer formed of an adhesive or an adhesive, and an edge portion of the adhesive layer on an edge portion of the release film. A pressure-sensitive adhesive sheet in which a bulging portion that projects outward is formed, and the bulging portion of the release film on one side and the bulging portion of the release film on the other surface are projected in an intersecting direction. Also provide.
Even in this pressure-sensitive adhesive sheet, the adhesive sheet can be used as a work table by holding the protruding part of the release film on one side with one hand and the protruding part of the release film on the other side with the other hand. It can be easily peeled off while being placed, and can be peeled off without causing crying separation. This is because the overhang is formed at the edge of the release film, so even if the adhesive sticks out, the end face is not hardened and the release film and the adhesive layer are easy to peel off, so that no tearing occurs. It seems to be.

  In addition, this pressure-sensitive adhesive sheet may be formed in a substantially rectangular shape in accordance with the shape of a display or the like. In this case, the short side of the release film on one side is used as an overhanging portion, and the release film on the other side is used. The long side should be an overhang.

  In any one of the above pressure-sensitive adhesive sheets, when the release films are formed on both sides, the thicknesses of both release films are preferably different. Since the thicker release film is easier to peel off, it is possible to further prevent tearing. Moreover, it is preferable to make the release force between the release film on one side and the adhesive layer different from the release force between the release film on the other side and the adhesive layer. Since the one where peeling force is smaller is easy to peel, it is possible to further prevent crying.

  In the pressure-sensitive adhesive sheet, it is preferable that a cut-out is formed in the release film and the adhesive layer with a laser to form the overhang portion. Conventionally, cutting was performed by pressing with a Thomson press blade mold, but the end face can be finished more precisely and cleanly with a laser.

  In general, a “sheet” is a thin product that is thin and generally has a thickness that is small instead of length and width, and “film” is thicker than its length and width as defined by JIS. A thin flat product with an extremely small thickness and a maximum thickness that is arbitrarily limited, usually supplied in the form of a roll (Japanese Industrial Standard JIS K6900). However, the boundary between the sheet and the film is not clear, and it is not necessary to distinguish between the two in terms of the present invention. Therefore, in the present invention, even when the term “film” is used, it includes “sheet” and is referred to as “sheet”. In some cases, “film” is included.

Hereinafter, the present invention will be described based on embodiments.
However, the embodiment described below is an example of the embodiment of the present invention, and the scope of the present invention is not limited to the following embodiment.

  As shown in FIG. 1, the pressure-sensitive adhesive sheet 1 of the first embodiment of the present invention is obtained by laminating a substantially rectangular release film 3 on one surface side of a substantially rectangular pressure-sensitive adhesive layer 4. The cut line 2 is formed along the peripheral edge.

  The cut line 2 divides the release film 3 and is formed in a substantially L shape along one short side and one long side of the peripheral edge of the release film 3. The portion of the release film 3 on the outer edge side of the release film 3 that is substantially L-shaped when viewed from the top is the outer portion 3a, the portion that is substantially rectangular when viewed from the top is the inner portion 3b, and the outer portion 3a and the inner portion. 3b can be separated separately. A bent portion of the cut line 2 is a corner portion 2a.

In the present embodiment, the cut line 2 is formed in a substantially L shape, but the present invention is not limited to this. The adhesive sheet 11 shown in FIG. Is formed into a substantially U-shape and has a cut line 12 having two corners 12a, or along the entire periphery of the peripheral portion of the release film 23 as in the adhesive sheet 21 shown in FIG. Thus, the cut line 22 having four corners 22a can be formed. In this way, the cut line may be formed so that it can be divided into two parts, the outer part and the inner part, along the peripheral edge of the release film, and one corner part so that the inner part can be easily peeled off. It is preferable to form so that it has.
However, the corner may be bent so as to be curved, or may be bent at an acute angle.

The release film 3 covers one surface of the pressure-sensitive adhesive layer 4 and is divided into the outer part 3a and the inner part 3b by the cut line 2 as described above.
The width of the outer portion 3a (the dimension indicated by L in FIG. 1) is preferably 1 mm or more, more preferably 3 mm or more, and preferably 20 mm or less, more preferably 10 mm or less.

  In this embodiment, the outer part 3a and the inner part 3b are divided into two parts, but the outer part 3a or the inner part 3b may be further divided into a plurality of parts.

  As a material of the release film 3, a synthetic resin film such as polyethylene, polypropylene, polyethylene terephthalate, paper, or the like can be used. The release film 3 is not particularly limited, but is preferably transparent from the standpoint of ease of alignment and easy inspection of defective products. The release film 3 may be subjected to a release treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment in order to facilitate the release from the adhesive layer 4. The peeling treatment may be performed on both sides of the release film 3.

  The thickness of the release film 3 is not particularly limited, but is 12 μm or more, preferably 25 μm or more and 250 μm or less, preferably 100 μm or less.

The pressure-sensitive adhesive layer 4 is a layer formed of an adhesive or a pressure-sensitive adhesive, and is preferably transparent or translucent.
Although it does not specifically limit as an adhesive agent thru | or an adhesive, A polymer material can be used, For example, using an acrylic adhesive, a rubber adhesive, an acrylic adhesive, a silicone adhesive etc. is used. it can. From the viewpoint of transparency and durability, a polymer material using an acrylic polymer is preferable.
As an example, a pressure-sensitive adhesive containing a base polymer, a crosslinking monomer, a crosslinking initiator, and a plasticizer can be used.

Examples of the base polymer include (meth) acrylic acid alkyl ester copolymers.
However, it is not intended to exclude all resins other than (meth) acrylic acid alkyl ester copolymers, and similar results can be obtained with resins other than (meth) acrylic acid alkyl ester copolymers. It can be assumed that there is a resin to be obtained.

The (meth) acrylate used for forming the (meth) acrylic acid alkyl ester copolymer, that is, as the alkyl acrylate or alkyl methacrylate component, the alkyl group is n-octyl, isooctyl, 2-ethylhexyl, n-butyl, One of alkyl acrylate or alkyl methacrylate which is any one of isobutyl, methyl, ethyl and isopropyl, or a mixture of two or more selected from these is preferable.
As other components, an acrylate or methacrylate having an organic functional group such as a carboxyl group, a hydroxyl group, or a glycidyl group may be copolymerized. Specifically, a monomer component obtained by appropriately and selectively combining the alkyl (meth) acrylate component and the (meth) acrylate component having an organic functional group as a starting material is subjected to heat polymerization to form a (meth) acrylate ester copolymer. A polymer polymer can be obtained.

  Among them, a (meth) acrylic acid ester-based copolymer containing α and β unsaturated carboxylic acid is preferable, for example, at least from iso-octyl acrylate, n-octyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and the like. The thing which copolymerized 1 or more types and acrylic acid can be mentioned.

  The glass transition temperature (Tg) of the base polymer is preferably −10 ° C. or less, particularly preferably −60 ° C. to −40 ° C., and its melt viscosity at 130 ° C. is 50,000 mPa · s or more, particularly 200,000 mPa · s to It is preferably 700,000 mPa · s, particularly preferably 200,000 mPa · s to 500,000 mPa · s.

  In addition, said glass transition temperature (Tg) and melt viscosity can be measured using a viscoelasticity measuring apparatus (For example, dynamic analyzer RDA-II by a rheometrics company). At that time, the melt viscosity may be measured by reading the viscosity (ηγ) value measured at a parallel plate 25 mmφ, strain 2%, 130 ° C., 0.02 Hz, and Tg was measured at a parallel plate 25 mmφ, strain 2%, frequency 1 Hz. What is necessary is just to read the temperature which shows the maximum value of Tanδ at the time.

As the cross-linking monomer, it is preferable to use an acrylic cross-linking monomer, and it is particularly preferable to use a polyfunctional (meth) acrylate. Specific examples include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and the like.
In addition, an organic functional group-containing (meth) acrylate monomer may be used. Examples of the organic functional group-containing (meth) acrylate monomer include a glycidyl group-containing (meth) acrylate monomer, a hydroxyl group-containing (meth) acrylate monomer, and an isocyanate group-containing (meth) acrylate monomer.

  In general, the content of the crosslinking monomer is preferably adjusted within a range of 0.01 to 1.0 part by weight with respect to 100 parts by weight of the base polymer. However, this range may be exceeded in balance with other elements.

Examples of the crosslinking initiator include a photoinitiator and a thermal polymerization initiator, and a photoinitiator is preferable.
As the photoinitiator, any of a cleavage type photoinitiator and a hydrogen abstraction type photoinitiator can be used, but preferably a hydrogen abstraction type, for example, benzophenone, Michler ketone, dibenzosuberone, 2-ethylanthraquinone. , Isobutylthioxanthone, or a mixed component composed of a combination of two or more of these is preferably used. However, the hydrogen abstraction type photoinitiator is not limited to the substances listed above.

  In general, the amount of the photoinitiator added is preferably adjusted within a range of 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the base polymer. However, this range may be exceeded in balance with other elements.

  The plasticizer can lower the overall storage shear modulus of the pressure-sensitive adhesive sheet.

  The plasticizer is preferably a liquid having a freezing point of −20 ° C. or less, particularly a liquid having a freezing point of −80 to −40 ° C., for example, adipic acid ester, phthalic acid ester, phosphoric acid ester, trimellitic acid A mixed component consisting of any one of ester-based, citrate-based, epoxy-based, polyester-based plasticizers, or a combination of two or more of these can be used and is compatible with (meth) acrylic acid ester-based copolymer polymers. Those that do are preferred. In the case of ultraviolet photocrosslinking, it is preferable to use a plasticizer that does not absorb ultraviolet rays.

  Moreover, generally the compounding quantity of a plasticizer is good to adjust within the range of the ratio of 0.1-200 weight part with respect to 100 weight part of base polymers.

In addition to the above components, pigments such as pigments and dyes having near-infrared absorption properties, tackifiers, antioxidants, anti-aging agents, hygroscopic agents, natural and synthetic resins, glass fibers, Various additives such as glass beads can be appropriately blended.
The adhesive or pressure-sensitive adhesive contains a polyisocyanate compound, polyamine compound, melamine compound, urea resin, epoxy resin, organic functional group-containing (meth) acrylate monomer, organic functional group-containing (meth) acrylate oligomer and other crosslinking agents. Alternatively, a photoinitiator, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, inorganic fine particles, and the like may be contained.

  The thickness of the adhesive layer 4 is not particularly limited, but is 5 μm or more, preferably 15 μm or more and 5 mm or less, preferably 2 mm or less. In particular, the thickness is preferably 0.25 mm.

Hereinafter, an example of the manufacturing method of the adhesive sheet 1 will be described.
An adhesive is applied to one side surface of the rectangular release film 3 to form an adhesive layer 4, and a substantially L-shaped cut is made at an appropriate position along the peripheral edge of the release film 3 to the depth of the release film 3. The adhesive sheet 1 can be formed by forming the cut line 2 by putting it.

In order to form the cut line 2, for example, a Thomson press blade mold or a laser cutter capable of adjusting the cut depth freely and accurately can be used. As the laser, a solid laser, a semiconductor laser, a liquid laser, a gas laser or the like is preferably used, and a CO ₂ laser or an Nd-YAG laser is particularly preferable.

  It is preferable to form the cut line 2 after the pressure-sensitive adhesive layer 4 is crosslinked. In this way, the pressure-sensitive adhesive does not easily protrude onto the cut line 2 and the release film 3 is more easily lifted.

When forming the cut line 2 with a laser, it is preferable to form the cut using an ultraviolet laser (for example, excimer laser) after forming the adhesive layer 4 with an adhesive to which an ultraviolet crosslinking agent is added.
Thereby, since the cut end face of the pressure-sensitive adhesive layer 4 is cross-linked by the ultraviolet rays and solidified at the same time as the cut is made, the release film 3 is further easily lifted.

  Moreover, it is preferable to irradiate the edge part of the adhesion layer 4 with the ultraviolet-ray containing 200-280 nm. Thereby, bridge | crosslinking of the edge part surface of the adhesion layer 4 advances, the stickiness of the edge part surface is suppressed, and handling of the adhesive sheet 1 can be made easy with buffer property and adhesive force maintained. Such an effect is particularly remarkable when an acrylic pressure-sensitive adhesive containing a hydrogen abstraction type photoinitiator is used as the pressure-sensitive adhesive layer 4.

  In order to obtain the pressure-sensitive adhesive sheets 11 and 21 shown in FIGS. 2 and 3, the adhesive layer 4 is formed by applying an adhesive to the rectangular release films 13 and 23 in the same manner as described above. , 23 may be cut into a substantially U shape or a substantially U shape to the depth of the release film to form the cut lines 12 and 22.

The adhesive sheet 1 can be used as follows.
As shown in FIG. 4, after the inner part 3b is lifted from the corner 2a and completely peeled off, the outer part 3a is raised from the corner of the peripheral edge of the release film 3 as shown in FIG. Can be peeled off. Conventionally, the end surfaces of the release film 3 and the adhesive layer 4 were fixed by an adhesive or the like protruding from the adhesive layer 4, but the adhesive sheet 1 was difficult to lift up. Since the cut line 2 is formed after being laminated on the pressure-sensitive adhesive layer 4, it is difficult for the adhesive to protrude from the cut line 2, and the adhesive layer 4 and the release film 3 are not easily fixed. For this reason, the inner part 3b can be easily lifted from the line, and the release film 3 can be easily peeled off. Moreover, since the inner part 3b is peeled from the inner side to the outer side of the pressure-sensitive adhesive sheet 1, the adhesive layer 4 is not lifted up and crying is not caused.
The outer portion 3a is formed with a narrow width along the peripheral edge portion, so that the adhesive strength with the adhesive layer is small, the adhesive portion 4 can be peeled off with a small peeling force, and the adhesive layer 4 can be lifted together. There is no crying separation.

Although the said adhesive sheet 1 can also be provided as an adhesive sheet with the form as it is, it is good also as the adhesive sheet 5 which stuck the release film and laminated | stacked on the other surface side of the adhesive layer 4 practically. In this case, it is preferable to laminate a release film 6 having a size larger than that of the adhesive layer 4 as shown in FIG. By doing in this way, since the end surface of the adhesion layer 4 is located inside the peripheral part of the release film 6, even if an adhesive protrudes, it can work without touching an adhesive.
Thus, when laminating the release films 3 and 6 on both sides of the pressure-sensitive adhesive layer 4, the cut lines 2 may be formed on each of the release films 3 and 6 on both sides. Is the same as that described in the pressure-sensitive adhesive sheet 1.

Moreover, the optical film 7 can be stuck and laminated | stacked on the other surface side of the adhesion layer 4 of the said adhesive sheet 1, and it can also be set as the optical member 8 as shown to FIG. 7A. Examples of the optical film 7 include a polarizing film, a polarization conversion element, a reflecting plate, a transflective plate, a retardation film, a brightness enhancement film, a protective film, an antireflection film, an electromagnetic wave shielding film, an optical compensation film, a near infrared cut film, Toning films and the like can be mentioned.
When it is set as the optical member 8, it is more preferable to laminate | stack the optical film 7a of a size larger than the adhesion layer 4 as shown to FIG. 7B. By doing in this way, since the end surface of the adhesion layer 4 is located inside the peripheral part of the release film 7a, even if an adhesive protrudes, it can work without touching an adhesive.

  When peeling off the release film of the pressure-sensitive adhesive sheet 5 or the optical member 8, the inner part 3b peels off the release film 3 from the inside by peeling off from the cut line, so that the pressure-sensitive adhesive layer 4 is peeled off without pulling up together. And crying does not occur. Moreover, since the outer side part 3a is formed narrow along the peripheral part, the adhesive force with the adhesive layer is small, it can be peeled off with a small peeling force, and it is difficult to cause crying separation.

  In the said form, when the peeling force by the side of the release film 3 is made smaller than the peeling force by the side of the release film 6, the release film 3 will peel easily and it will become difficult to produce a crying separation. Moreover, in the case of the optical member 8, since the adhesion layer is stuck directly on the optical film 7, the release film 3 becomes easy to peel more reliably.

In order to make the peel force different, it is preferable to make the release film 3 and the release film 6 have different thicknesses and materials, or make the peel force on both sides of the adhesive layer itself different.
For example, a pressure-sensitive adhesive composition is prepared by blending a (meth) acrylic acid ester copolymer polymer and a hydrogen abstraction type photoinitiator, and applied to a thickness of 20 μm to 2000 μm, preferably 50 μm to 1000 μm. The surface to be formed and lower in adhesive strength is harder than the other surface by increasing the irradiation amount of ultraviolet rays in the region of 200 nm to 280 nm (especially 254 nm) to promote cross-linking compared to the other surface. Thus, the adhesive force can be further reduced, and the peel forces on both sides can be made different.

  At this time, the difference in peel force between the release force on the release film 3 side and the release force on the release film 6 side or the optical film 7 side is preferably 5 mN or more, more preferably 15 mN or more, and even more preferably 150 mN or more. To do.

In addition, the peeling force in this case can be measured as follows.
Peel off the release paper on one side of the double-sided tape (No. 502 manufactured by Nitto Denko Corporation) cut to a width of 50 mm, apply a load of 2 kg with a rubber roller, and apply the double-sided tape to the measurement surface (release surface) of the release film. to paste together. The release film is cut according to the width of the double-sided tape, and heat-treated at 100 ° C. for 1 hour in a hot air circulating thermostat. After that, the release paper on the other side of the double-sided tape is peeled off and bonded to a 5 cm x 5 cm x 5 mm vinyl chloride auxiliary plate under a 2 kg load with a rubber roller. The release film and lower chuck are attached to the upper chuck of the tensile tester. Auxiliary plate is fixed to the two, and the load to be peeled is measured by pulling both chucks in the opposite direction at a speed of 300 mm / min.

  In addition, although the adhesive sheet 1 is formed in the substantially rectangular shape, it is not limited to this, It can also form in an ellipse shape.

  Next, the adhesive sheet of 2nd embodiment is demonstrated.

  The pressure-sensitive adhesive sheet 31 of the second embodiment of the present invention is formed by laminating substantially rectangular release films 33 and 36 on both sides of a pressure-sensitive adhesive layer 34 formed in a substantially rectangular shape. There are overhang portions 33a and 36a formed so that the edge portions of the films 33 and 36 protrude outward from the end edge portion 34a of the adhesive layer 34. The projecting part of the release film on the surface side is formed so as to project in a different direction.

  For example, as shown in FIG. 8, both short sides of the release film 36 of the substantially rectangular pressure-sensitive adhesive sheet 31 are projected outward from the end edge part 34a of the adhesive layer 34 to form a projecting part 36a. Both long sides of the substantially rectangular shaped release film 33 are projected outward from the edge portion 34a of the adhesive layer 34 to form an extended portion 33a, and the extended portions 33a and 36a of the release films 33 and 36 are provided. It is good to form so that it may protrude in the direction which mutually cross | intersects.

  The overhanging portion 33a (36a) is projected from the end edge portion 34a of the adhesive layer 34 by 1.0 mm or more, preferably 3.0 mm or more. Moreover, the length of the overhang of the release films 33 and 36 may be different.

  As a material of the release film 33 (36), the same material as that used in the release film 3 of the pressure-sensitive adhesive sheet 1 of the first embodiment can be used.

  The thickness of the release film 33 (36) is not particularly limited, but is 12 μm or more, preferably 25 μm or more and 250 μm or less, preferably 100 μm or less.

The thicknesses of the release films on both sides are preferably different from each other.
If it does in this way, the direction of a thick release film will become easy to peel, and it can prevent crying parting further.
For example, when the side to be peeled first is the release film 33, it is preferable that the release film 33 has a thickness of 100 μm and the release film 36 has a thickness of 38 μm.

The pressure-sensitive adhesive layer 34 is a layer formed of an adhesive or a pressure-sensitive adhesive, and is preferably transparent or translucent.
As an adhesive thru | or adhesive, the thing similar to what was used with the adhesive layer 4 of the adhesive sheet 1 of said 1st embodiment can be used.

  The thickness of the adhesive layer 34 is not particularly limited, but is 5 μm or more, preferably 15 μm or more, and 5 mm or less, preferably 2 mm or less. In particular, 0.5 mm is preferable.

Hereinafter, the manufacturing method of the adhesive sheet 31 is shown.
As a method for producing the pressure-sensitive adhesive sheet 31, for example, a pressure-sensitive adhesive is applied to one surface of the release film 33 except for the overhanging portion 33a, and the release film 36 is overlaid thereon except for the overhanging portion 36a. The adhesive sheet 31 can be formed.

  Further, after applying a pressure-sensitive adhesive to the entire surface of the release film and pasting the release film having the same size as the release film on the pressure-sensitive adhesive, the release film is released from one release film side. It is also possible to make a cut in the film and the pressure-sensitive adhesive layer, and then make a cut in the release film and the pressure-sensitive adhesive layer from the side of the other release film, and peel off the outer part to form an overhanging portion.

  For example, as shown in FIG. 9A, cuts 9 are made along the long sides to the depths of the release film 36 and the adhesive layer 34 so as not to cut the release film 33 from the release film 36 side. The release film 33 and the adhesive layer 34 are cut along both short sides so as not to cut the release film 36 from the release film 33 side. And as shown in FIG.9 (B), if the outer edge part side 10 which made the cut is peeled, it can be set as the adhesive sheet 31 which has the overhang | projection parts 33a and 36a.

In order to make the cut, for example, a Thomson press blade mold or the like can be used, but it is preferable to use a laser cutter because the finish of the end face and the depth of cut can be adjusted freely and accurately. As the laser, a solid laser, a semiconductor laser, a liquid laser, a gas laser or the like is preferably used, and a CO ₂ laser or an Nd: YAG laser is particularly preferable.
When a laser cutter is used, the stickiness of the surface of the edge of the adhesive layer 34 is temporarily suppressed (for example, about one day) by the action of heat and the like, and the adhesive sheet 31 is easily handled.

When forming a cut with a laser, it is particularly preferable to form the cut using an ultraviolet laser (for example, excimer laser) after forming the adhesive layer 34 with an adhesive to which an ultraviolet crosslinking agent is added.
Thereby, at the same time as making the cut, the cut end surface of the adhesive layer 34 is cross-linked and solidified by the ultraviolet rays, so that the release film 33 (36) is more easily raised.

  Moreover, in the said embodiment, it is good to form so that the peeling force of the release film of one surface side and an adhesive layer may differ from the release film of an other surface side, and the peeling force of an adhesive layer.

  In order to make the peel force different, as shown in the pressure-sensitive adhesive sheet of the first embodiment, the thickness and material of the release film on both sides are made different, or the peel force on both the front and back sides of the adhesive layer itself is made different. That's fine. However, it is not limited to these.

  The edge 34a of the adhesive layer 34 is preferably irradiated with ultraviolet rays including 200 to 280 nm. Thereby, the bridge | crosslinking of the edge part surface of the adhesion layer 4 advances, the stickiness of the edge part surface is suppressed, and handling of the adhesive sheet 31 can be made easy, maintaining buffer property and adhesive force. Such an effect is particularly remarkable when an acrylic pressure-sensitive adhesive containing a hydrogen abstraction type photoinitiator is used as the pressure-sensitive adhesive layer 34.

  Although the said adhesive sheet 31 is exhibiting substantially rectangular shape, it is not limited to this, It can also form in ellipse shape etc.

  Moreover, a release film can be laminated | stacked on the one surface side of the adhesion layer 34, and an optical film can also be laminated | stacked on the other surface side, and it can also be set as an optical member. Examples of the optical film include a polarizing film, a polarization conversion element, a reflecting plate, a transflective plate, a retardation film, a brightness enhancement film, a protective film, an antireflection film, an electromagnetic wave shielding film, an optical compensation film, a near-infrared cut film, a control film, and the like. Various materials used for a display panel of a flat-type image device such as a color film or a laminate obtained by combining them can be used.

  Hereinafter, examples will be described, but the present invention is not limited thereto.

(Example 1)
As the release film on the one side, a release PET film (Mitsubishi Chemical Polyester Film Co., Ltd .; trade name MRF38) having a thickness of 38 μm was used. A 5 mm adhesive layer was formed. As an adhesive, 100 parts by weight of an acrylic ester copolymer, 1.0 part by weight of benzophenone as a hydrogen abstraction type photoinitiator, 0.8 part by weight of 1,4-butanediol diacrylate as a crosslinking monomer are added, What was melt-stirred at 130 ° C. was used. Furthermore, a 100 μm-thick release PET film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd .; trade name MRF100) is pasted on this adhesive layer as a release film on the other side, and laminated in a sheet form. Molded. Next, a laminated sheet A was obtained by irradiating a single-side accumulated light amount of 2000 mJ / cm ² from both sides through a release film using a high-pressure mercury lamp.
The composition of the acrylic ester copolymer is a copolymer of 78.4 parts by weight of n-butyl acrylate, 19.6 parts by weight of 2-ethylhexyl acrylate, and 2.0 parts by weight of acrylic acid. -35 ° C. and 130 ° C. melt viscosity was 250,000 (mPa · sec). Further, the integrated light amount was measured by attaching a 365 nm sensor to UIT-150 manufactured by USHIO.

The laminated sheet A was cut with a laser cutter from the one surface side so as to have an outer dimension of 590 × 1000 mm.
Next, a cut was made to the depth of the adhesive layer with a laser cutter along the entire peripheral edge of the film at a position 5 mm inside from the outer edge of the release film on the one surface side. This half cut can change the depth of cut by adjusting the laser output and the cutting speed according to the thickness and material of the adhesive layer and the release film, and can be half cut.

  As shown in FIG. 10, the outer periphery of the release film on the one surface side is peeled off from the outer edge side of the cut of the adhesive layer, and the outer periphery of the release film on the other surface is outside the end surface of the adhesive layer. It was made into the shape which protrudes in the direction. After that, at the position 3 mm inside from the outer edge of the release film on the one surface side, cut into the depth of the release film with a laser cutter in an L shape along the peripheral edge of the two sides to form a cut line, It was set as the adhesive sheet which has a substantially L-shaped cut line as shown in FIG.

(Example 2)
As the release film on the one side, a release PET film (Mitsubishi Chemical Polyester Film Co., Ltd .; trade name MRF38) having a thickness of 38 μm was used. An 8 mm adhesive layer was formed. As an adhesive, 25 parts by weight of DIDP as a plasticizer, 100 parts by weight of a hydrogen abstraction type photoinitiator (manufactured by Lam-Berti; trade name Esacure TZT) as a crosslinking agent with respect to 100 parts by weight of an acrylic polymer A mixture prepared by adding 1.0 part by weight of 1,9-nonanediol diacrylate and melting and stirring at 130 ° C. was used. Further, a 75 μm-thick release PET film (Mitsubishi Chemical Polyester Film Co., Ltd .; trade name: MRF75) is pasted on the adhesive layer as a release film on the other side, and laminated in a sheet form and hot melt molded did. Next, a laminated sheet B was obtained by irradiating a single-side integrated light amount of 3600 mJ / cm ² from both sides through a release film using a high-pressure mercury lamp.
The composition of the acrylic polymer was obtained by polymerizing 100 parts by weight of 2-ethylhexyl acrylate, Tg was −45 ° C., and the melt viscosity at 130 ° C. was 260,000 (mPa · sec). Further, the integrated light amount was measured by attaching a 365 nm sensor to UIT-150 manufactured by USHIO.

The laminated sheet B was cut with a laser cutter from the one side so as to have an outer dimension of 590 × 1000 mm.
Next, a cut was made to the depth of the adhesive layer with a laser cutter along the entire circumference of the film at a position 5 mm inside from the outer edge of the release film on the one surface side.

  The release film on the one surface side and the outer edge side of the cut of the adhesive layer are peeled off, and as shown in FIG. 11, the outer edge portion of the release film on the other surface side is more than the end surface of the adhesive layer over the entire circumference. The shape was formed to project outward. Then, in the release film on the one surface side, at a position 3 mm inside from the outer edge, along the peripheral edge of the three sides, a U-shaped cut with a laser cutter to the depth of the release film, forming a cut line, It was set as the adhesive sheet which has a notch line as shown in FIG.

(Comparative Example 1)
The laminated sheet A produced in Example 1 was punched out with the same dimensions as the release film and the adhesive layer with a Thomson press blade so that the outer dimensions would be 580 × 990 mm, to obtain an adhesive sheet as shown in FIG. .

(Comparative Example 2)
The laminated sheet B produced in Example 2 was punched out with the same dimensions as the release film and the adhesive layer with a Thomson press blade so that the outer dimensions would be 580 × 990 mm, to obtain an adhesive sheet as shown in FIG. .

(Evaluation)
Ten release sheets of Examples 1 and 2 and Comparative Examples 1 and 2 were used, and the release film having a thickness of 38 μm was peeled off.
In Examples 1 and 2, the inner part is peeled off from the corner of the cut line, and then the outer part is peeled off. In Comparative Examples 1 and 2, the film is peeled from one corner of the peripheral part of the release film. I did it.
The results are shown in Table 1 below.

(result)
In all of the pressure-sensitive adhesive sheets of Examples 1 and 2, the release film could be peeled off without causing crying separation.
In Comparative Example 1, crying separation occurred in 4 sheets, and in Comparative Example 2, crying separation occurred in 7 sheets.

(Example 3)
As the release film on the one side, a release PET film (Mitsubishi Chemical Polyester Film Co., Ltd .; trade name MRF38) having a thickness of 38 μm was used. A 25 mm adhesive layer was formed. As an adhesive, 100 parts by weight of an acrylic ester copolymer, 1.0 part by weight of benzophenone as a hydrogen abstraction type photoinitiator, 0.8 part by weight of 1,4-butanediol diacrylate as a crosslinking monomer are added, An adhesive was obtained by melting and stirring at 130 ° C. A release PET film having a thickness of 100 μm (manufactured by Fujimori Kogyo Co., Ltd .; trade name film binder 100E_0010BD) was pasted thereon as a release film on the other side, laminated in a sheet shape, and hot melt molded. Next, using a high-pressure mercury lamp, a laminated sheet C was obtained by irradiating both sides with a one-side integrated light quantity of 2000 mJ / cm ² through a release film.
The composition of the acrylic ester copolymer is a copolymer of 78.4 parts by weight of n-butyl acrylate, 19.6 parts by weight of 2-ethylhexyl acrylate, and 2.0 parts by weight of acrylic acid. -35 ° C. and 130 ° C. melt viscosity was 250,000 (mPa · sec). Further, the integrated light amount was measured by attaching a 365 nm sensor to UIT-150 manufactured by USHIO.

The laminated sheet C was cut with a laser cutter so as to have an outer dimension of 590 × 1000 mm.
Next, after cutting with the laser cutter to the depth of the release film and the adhesive layer at a position 5 mm inside from the outer edge along both opposing long sides of the release film on the one surface side, A cut was made to the depth of the release film and the adhesive layer at a position 5 mm inside from the outer edge along both short sides opposite to the release film.
The outer edge side of the release film and adhesive layer with a cut is peeled off, and has a protruding portion with a width of 5 mm on both short sides of the release film with a thickness of 38 μm as shown in FIG. 14, and has a thickness of 100 μm. An adhesive sheet having a protruding portion having a width of 5 mm was formed on both long sides of the release film.

(Comparative Example 3)
The laminated sheet C produced in Example 3 was punched out of the release film and the adhesive layer with the same dimensions so that the outer dimensions were 590 × 1000 mm with a Thomson press blade, and the adhesive sheet as shown in FIG. did.

(result)
Using 10 sheets of each of Example 3 and Comparative Example 3, the release PET film on the 100 μm side was peeled off to evaluate whether tearing occurred.
In the examples, all the release PET films on the 100 μm side could be peeled without causing crying separation. On the other hand, in the comparative example, crying separation occurred with 7 sheets.

1st Embodiment of the adhesive sheet of this invention is shown, (A) is a side view, (B) is a top view. 1 shows another embodiment of the pressure-sensitive adhesive sheet of FIG. 1, (A) is a side view, and (B) is a top view. 1 shows another embodiment of the pressure-sensitive adhesive sheet of FIG. 1, (A) is a cross-sectional view, and (B) is a top view. It is the top view which showed the state which peels the inner side part of the release film of the adhesive sheet shown in FIG. It is the top view which showed the state which peels the outer side part of the release film of the adhesive sheet shown in FIG. One Embodiment of the adhesive sheet which laminated | stacked the release film on both surfaces side is shown, (A) is a side view, (B) is a top view. One Embodiment of the optical member which laminated | stacked the release film on the one surface side and laminated | stacked the optical film on the other surface side is shown, (A) is a side view, (B) is a top view. The modification of the optical member shown to FIG. 7A is shown, (A) is a side view, (B) is a top view. 2nd embodiment of the adhesive sheet of this invention is shown, (A) is a side view, (B) is a top view, (C) is a front view. It is an example of the manufacturing method of the adhesive sheet of FIG. 8, (A) is sectional drawing which showed the state which put the notch | incision, (B) is sectional drawing which showed the state which peeled the outer edge part side. . The adhesive sheet of Example 1 used in the Example of this invention is shown, (A) is a side view, (B) is a top view. The adhesive sheet of Example 2 used in the Example of this invention is shown, (A) is a side view, (B) is a top view. The adhesive sheet of the comparative example 1 used in the Example of this invention is shown, (A) is a side view, (B) is a top view. The adhesive sheet of the comparative example 2 used in the Example of this invention is shown, (A) is a side view, (B) is a top view. The adhesive sheet of Example 3 used in the Example of this invention is shown, (A) is a side view, (B) is a top view, (C) is a front view. The adhesive sheet of the comparative example 3 used in the Example of this invention is shown, (A) is a side view, (B) is a top view. It is the schematic side view which showed the protrusion of the adhesive which had arisen with the conventional adhesive sheet. It is the schematic perspective view which showed the crying separation which had arisen with the conventional adhesive sheet.

Explanation of symbols

1, 11, 21, 31 Adhesive sheet 2, 12, 22 Cut line 2a, 12a, 22a Corner part 3, 13, 23, 33 Release film 3a, 13a, 23a Outer part 3b, 13b, 23b Inner part 33a Overhang Part 4, 34 Adhesive layer 5 Adhesive sheet 6, 36 Release film 36a Overhang part 7 Optical film 8 Optical member 9 Notch 10 Outer edge side

Claims (8)

  In a pressure-sensitive adhesive sheet having a structure in which a release film is laminated on at least one surface side of a pressure-sensitive adhesive layer formed of an adhesive or a pressure-sensitive adhesive, a cut line is formed along the peripheral edge of the release film, and the outside of the cut line A pressure-sensitive adhesive sheet characterized in that the inner part and the inner part can be separated from the pressure-sensitive adhesive layer separately.   In a pressure-sensitive adhesive sheet having a structure in which a release film is laminated on both sides of an adhesive layer formed with an adhesive or a pressure-sensitive adhesive, a score line is formed along the peripheral edge of the release film on one side or both sides, A pressure-sensitive adhesive sheet, characterized in that an outer portion and an inner portion of the cut line can be separately separated from the pressure-sensitive adhesive layer.   In an optical member having a configuration in which a release film is laminated on one side of an adhesive layer formed of an adhesive or an adhesive and an optical film is laminated on the other side, a score line is formed along the peripheral edge of the release film. An optical member characterized in that the outer part and the inner part of the score line can be separated from the adhesive layer separately.   In a pressure-sensitive adhesive sheet having a configuration in which release films are laminated on both sides of a pressure-sensitive adhesive layer formed of an adhesive or pressure-sensitive adhesive, the edge of the release film projects outward from the edge of the pressure-sensitive adhesive layer. A pressure-sensitive adhesive sheet in which an overhanging portion is formed, and the overhanging portion of the release film on one side and the overhanging portion of the release film on the other side are overhanging.   The pressure-sensitive adhesive sheet according to claim 4, wherein the short side of the release film on the one surface side of the substantially rectangular shape is the overhang portion, and the long side of the release film on the other surface side of the substantially rectangular shape is the overhang portion.   The pressure-sensitive adhesive sheet according to any one of claims 2, 4, and 5, wherein the thicknesses of the release films on both sides are made different.   The release film on the one side and the release force between the adhesive layers are different from the release force on the other side and the release force between the adhesive layers. Adhesive sheet.   The pressure-sensitive adhesive sheet according to any one of claims 4 to 7, wherein a protruding portion is formed by cutting a release film and a pressure-sensitive adhesive layer with a laser.

Images