JPH0676347U - Double-sided adhesive - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a double-sided pressure-sensitive adhesive body that can be peeled off even if two adherends have smooth surfaces and are hard. [Structure] In a double-sided pressure-sensitive adhesive body in various forms such as a tape shape, a film shape, and a sheet shape, at least one pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive containing a large amount of a plasticizer to have weak adhesion. [Effect] Although it adheres to the smooth surface of the hard adherend by wetting due to the use of a large amount of plasticizer, it can be easily peeled off if necessary.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a double-sided pressure-sensitive adhesive body. Here, the “adhesive body” is a concept that includes an adhesive tape, an adhesive sheet, an adhesive film, an adhesive plate, and the like.

[0002]

[Prior art]

 Various adhesive tapes are used in the manufacturing process of a liquid crystal display module using a TFT of a notebook personal computer. For example, the glass TFT substrate of the liquid crystal cell and the backlight structure are adhered to each other by using double-sided adhesive tape on the periphery of each piece so as to prevent misalignment in the subsequent steps. In this case, it is often the case that dust is present between the TFT substrate and the backlight structure after adhesion, or a defect is found in either the liquid crystal cell or the backlight structure. In such a case, peel off both of the above to remove dust or reuse the one with no defects.

However, the double-sided pressure-sensitive adhesive tape that has been used conventionally has a high adhesive strength measured according to “JIS Z0237” of about 300 g / 25 mm width on both sides, which makes it difficult to separate the liquid crystal cell from the backlight structure. It may take a long time and the parts may be destroyed as described above.

[0004]

[Problems to be solved by the device]

 The present invention solves the above-mentioned drawbacks of the conventional double-sided adhesive tape.

[0005]

[Means for solving problems]

 According to the present invention, in a double-sided pressure-sensitive adhesive body having pressure-sensitive adhesive layers on both sides of a substrate and having a separator on the outer surface of each pressure-sensitive adhesive layer, at least one of the two pressure-sensitive adhesive layers is a mirror surface. Provided is a double-sided pressure-sensitive adhesive body, which has a weak adhesiveness such that even a finish hard adherend can be peeled off.

The present invention will be described in detail below. Substrates used for the double-sided adhesive of the present invention include films of various polymers such as polyester, rigid or semi-rigid polyvinyl chloride, acetate plastic, polycarbonate and polypropylene, sheets of various polymers as described above, and various papers. Examples thereof include various foam sheets such as neoprene foam, polyethylene foam, and urethane foam, and in some cases, various plates such as glass plate and acrylic plate may be used.

The surface of the substrate on which the slightly tacky pressure-sensitive adhesive layer is provided is such that the outer surface of the pressure-sensitive adhesive layer applied is as smooth as possible (this also depends on the thickness of the pressure-sensitive adhesive layer). ), And it may be preferable that the mirror surface is formed. From this point of view, when a foamed sheet is used, it may be preferable to provide a film having a smooth surface by fusion bonding, adhesion or adhesion on the surface on which the weak adhesive layer is provided. In this case, when both pressure-sensitive adhesive layers of the double-sided pressure-sensitive adhesive body of the present invention have weak adhesiveness, it may be preferable to similarly provide a surface smooth film on both surfaces of the foamed sheet. The advantage of using the foamed sheet is that the unevenness can be absorbed when the adherend is not smooth. In this case, the substrate means a structure including the foam sheet and the film attached thereto.

For the strong pressure-sensitive adhesive layer that may be used in the double-sided pressure-sensitive adhesive body of the present invention, various pressure-sensitive adhesives usually used in various fields may be used, and examples thereof include acrylic-based, rubber-based, and silicone-based adhesives. These adhesives may be crosslinked, may not be crosslinked, and may contain various additives such as a tackifier.

The slightly adhesive PSA layer used in the double-sided PSA of the present invention uses various polymers such as acrylic, rubber, silicone, polyvinyl chloride and alkyd resin as the main polymer. However, if a large amount of plasticizer is added to this, the adhesive force is extremely weak, but so-called "stickiness" occurs, and the stickiness causes the adhesion to a smooth surface such as a mirror surface (due to airtightness). It was used. Therefore, even if the adherends on both surfaces are hard materials, they can be peeled off on the surface of this weakly adhesive pressure-sensitive adhesive layer. The main material polymer may be crosslinked to some extent.

As the above-mentioned plasticizer, although the type may vary depending on the main material polymer, a wide variety of commercially available plasticizers can be used. Examples thereof include phthalic acid ester-based, phosphoric acid ester-based, fatty acid ester-based, chlorine compound-based, epoxidized oil-based, polyester-based, low molecular weight silicone-based and the like. For polyvinyl chloride, low molecular weight saturated polyesters, dibutyl phthalate (DBP), dioctyl phthalate (DOP), etc. can be used, to name but a few. For the alkyd resin, DOP, dioctyl adipate (DOA) or the like can be used. Low molecular weight silicones can be used as plasticizers for silicone based polymers. Needless to say, two or more plasticizers may be used in combination.

If these plasticizers are added in an amount of 40 to 400 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the main polymer, a weak tackiness is obtained, but the amount of the plasticizer is limited to the above range. It depends on the type and molecular weight of the main polymer, and the desired adhesive strength.

The adhesive force of such a weakly adhesive pressure-sensitive adhesive layer is preferably in the range of more than 0 g / 25 mm width to 200 g / 25 mm width, more than 0 g / 25 mm width of 50 g as measured by “JIS Z0237”. A range up to / 25 mm width is more preferable, and a range exceeding 0 g / 25 mm width and up to 20 g / 25 mm width is further preferable.

The thickness of the substrate is not particularly limited, but can be selected within a wide range, for example, from about 5 μm in the case of a film to about 5 mm in the case of a foamed sheet or plate. The thickness of the two pressure-sensitive adhesive layers is not particularly limited, but can be selected from the range of, for example, about 3 μm to about 300 μm.

A known method can be used to form each pressure-sensitive adhesive layer, and examples thereof include a method of applying a pressure-sensitive adhesive solution, heating and drying, and calender coating. As is well known in the art, it is preferable that the substrate is subjected to a primer treatment or a corona treatment prior to the formation of the pressure-sensitive adhesive layer to improve the adhesion between the substrate and the pressure-sensitive adhesive layer.

[0015]

[Action]

 If the double-sided adhesive body of the present invention is used in the form of a tape to manufacture the liquid crystal display module of the notebook personal computer described in the prior art, at least one adhesive layer has a weak adhesiveness, At least the TFT substrate has a smooth glass surface, so if the two are adhered with a weak adhesive layer, the position of the backlight structure will be fixed sufficiently, and if necessary. It can be peeled off.

[0016]

【Example】

 Hereinafter, the present invention will be described in more detail by way of examples with reference to FIGS. 1 and 2, but the present invention is not limited to the examples.

Example 1 On both sides of a double-sided corona-treated expanded polyethylene sheet 1 having a thickness of about 550 μm, crosslinked acrylic strong adhesive layers 2 and 3 having a thickness of about 40 μm are provided. Specifically, about 30% by weight of a cross-linkable acrylic adhesive solution was used on the separator 4 and another separator (ethyl acetate was used as the solvent. Instead, methyl ethyl ketone, methyl isobutyl ketone, and toluene were used instead. Etc. may be used, or a mixed solvent thereof may be applied, and the mixture is heated and dried, and then laminated on both surfaces of a foamed polyethylene sheet to form strong adhesive layers 2 and 3.

On the other hand, on one side of a semi-rigid polyvinyl chloride film 5 having a thickness of about 50 μm, for example, 200 parts by weight of DOP is added to 100 parts by weight of a relatively low molecular weight polyvinyl chloride to prepare a weak tacky adhesive. The agent is subjected to calendar coating to provide a weak adhesive layer 6 having a thickness of about 55 μm. A special separator 7 with a mirror surface is stuck on it. In addition, a thin foreign layer may be provided on one surface of the semi-rigid polyvinyl chloride 5 so as to almost completely prevent DOP migration.

Next, the separator on the strong adhesive layer 2 on the foamed polyethylene sheet 1 is peeled off, and the other surface of the semi-rigid polyvinyl chloride 5 is bonded on the strong adhesive layer 2, The double-sided pressure-sensitive adhesive sheet of the present invention as shown in FIG.

The adhesive force of the weak pressure-sensitive adhesive layer 6 thus formed was about 10 g / 25 mm width when measured according to “JIS Z0237”.

Example 2 The same crosslinkable acrylic pressure-sensitive adhesive solution as that used in Example 1 was applied onto the vapor-deposited surface of an aluminum vapor-deposited polyethylene terephthalate film 8 having a thickness of about 30 μm, followed by heating and drying to a thickness of about 30 μm. The crosslinked acrylic strong adhesive layer 9 is formed, and the separator 10 is attached thereon.

On the opposite side of the film 8, a weakly tacky adhesive prepared by adding about 150 parts by weight of a low molecular weight silicone as a plasticizer to 100 parts by weight of a high molecular weight silicone was calender coated, A weak pressure-sensitive adhesive layer 11 having a thickness of about 50 μm is formed, and a special separator 12 having a mirror surface is bonded on the weak pressure-sensitive adhesive layer 11 to obtain a double-sided pressure-sensitive adhesive body of the present invention as shown in FIG.

The adhesive force of the weak pressure-sensitive adhesive layer 11 thus formed was about 15 g / 25 mm width when measured according to “JIS Z0237”.

[0024]

[Effect of device]

 If the double-sided adhesive body of the present invention is used for manufacturing a liquid crystal display module of a notebook personal computer, for example, after the TFT substrate of the liquid crystal cell and the backlight structure are attached, dust may be found between them. When a defect is found in either the liquid crystal cell or the backlight structure, both can be separated at the weak adhesive layer of the double-sided adhesive, and reused without discarding parts without defects. it can.

Also, the weak adhesive layer adheres to glass, ceramics, plastics, etc. if it is a smooth surface, so hard materials can be joined with the double-sided adhesive body of the present invention, and peeled off if necessary. You can This is an effect that the conventional double-sided pressure-sensitive adhesive body does not have. Therefore, it can be used for various applications such as joining nameplates with smooth back surfaces. When the nameplate is bonded to a smooth door, the two adhesive layers may have weak adhesion.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of an example of a double-sided pressure-sensitive adhesive body of the present invention.

FIG. 2 is a sectional view showing the structure of another example of the double-sided pressure-sensitive adhesive body of the present invention.

[Explanation of symbols]

1 Foamed Polyethylene Sheet 2 Strong Adhesive Layer 3 Strong Adhesive Layer 4 Separator 5 Semi-Hard Polyvinyl Chloride Film 6 Weak Adhesive Layer 7 Specular Separation Special Separator 8 Aluminum Deposition Polyethylene Terephthalate Film (Substrate) 9 Strong Adhesive Layer 10 Separator 11 Weak adhesive layer 12 Mirror surface forming special separator

Claims (3)

[Scope of utility model registration request] 1. In a double-sided pressure-sensitive adhesive body having pressure-sensitive adhesive layers on both sides of a substrate and having a separator on the outer surface of each pressure-sensitive adhesive layer, at least one of the two pressure-sensitive adhesive layers is a mirror-finish hard coating. A double-sided pressure-sensitive adhesive body characterized by having a weak adhesiveness such that it can be peeled off even when attached. 2. The double-sided pressure-sensitive adhesive body according to claim 1, wherein one pressure-sensitive adhesive layer has strong adhesiveness. 3. The double-sided pressure-sensitive adhesive body according to claim 1, wherein the substrate is formed by fusing, adhering or sticking a foamed sheet and a film on at least one surface thereof.