JP2003080638A - Release liner and double-faced tape using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel low silicone migration release liner which reduces the migration of silicone without changing a conventional silicone release liner, performance, and costs and a double-faced tape using the release liner. SOLUTION: In the release liner, the release layer contains poly (dimethyl siloxane) having a vinyl group or a hexenyl group as a functional group as a main agent. Moreover, the release liner is cured by using poly (methylhydrodiene siloxane) as a crosslinking agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release liner for a label, tape or sheet using a pressure sensitive adhesive (adhesive), a heat sensitive adhesive, a prepreg adhesive, etc., and a double-sided tape using the same. Adhesive tapes, adhesive labels, adhesive sheets, prepreg adhesive sheets, heat-sensitive adhesive tapes that are suitable for manufacturing and assembling processes and products of hard disk drives (HDD), semiconductors, relays and other electronic parts and devices that do not like silicone contamination. The present invention relates to a release liner used for sheets and the like and a double-sided tape using the release liner.

[0002]

2. Description of the Related Art Today, pressure-sensitive adhesive tapes, pressure-sensitive adhesive labels, pressure-sensitive adhesive sheets, heat-sensitive adhesive tapes, sheets and prepreg adhesive sheets are widely used in various industrial fields. In these tapes, labels and sheets, a release liner is laminated on the surface of an adhesive (pressure-sensitive adhesive, heat-sensitive adhesive, prepreg adhesive, etc.) layer for the purpose of protecting the adhesive layer until use. As such a release liner, a silicone-based release liner in which a silicone-based release agent is applied to a base material such as paper, a plastic film, or a polyolefin laminated paper is generally widely used, and has a structure schematically shown in FIG. Has become. This silicone-based release liner has been used for over 50 years due to its excellent release performance, stability over time, and little adverse effect on adhesives, and its production amount has been steadily increasing.

However, in recent years, HDDs, semiconductors, relays,
In the industrial field of switches and other precision electronic devices (parts), transfer of silicone release liner to the adhesive side of tapes, labels and sheets, and the secondary transfer of this transferred silicone to electronic parts and devices. It has been found that the mixture due to the above causes problems such as a head crash of the HDD and a contact failure. Therefore, a release liner using a non-silicone release agent that does not cause these problems, such as a fluorine release agent or a polyolefin release agent, has been developed in recent years.

However, the fluorine-based release liner has a problem that toxic hydrofluoric acid is generated during incineration, and there is an economical problem that the release agent is expensive to produce. On the other hand, the polyolefin-based release liner does not generate harmful gas, but it still has an economical problem that the manufacturing cost is higher than that of the conventional silicone-based release liner, and the release performance is slightly higher than that of the silicone-based release liner. There is also the problem of being inferior.

Further, Japanese Unexamined Patent Publication No. 2001-3010 discloses an invention relating to a pressure-sensitive double-sided adhesive sheet and a pressure-sensitive adhesive member. As a double-sided tape for HDD, a non-silicone type release layer is formed on one surface of the pressure-sensitive adhesive layer. A liner having a silicone-based release liner laminated on the other surface has been proposed. However, use of a conventional silicone-based release liner on one side is not preferable because the silicone may migrate to the adhesive surface in many cases.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a novel silicone-based release liner in which the transfer of silicone is greatly reduced in the above-mentioned industrial fields where the transfer of silicone is a problem, while the performance and cost are not significantly different from those of the conventional silicone-based release liner. It is an object of the present invention to provide a silicone low migration release liner and a double-sided tape using the release liner.

[0007]

As a result of various studies to achieve the above object, the inventors of the present invention have found that the silicone composition of the release liner and the coating amount of the release layer are limited, so that the conventional silicone type The inventors have invented a release liner capable of significantly reducing the migration amount of silicone as compared with the migration amount of silicone in the release liner. Further, in the double-sided tape, by using this novel release liner as at least one release liner,
The present invention has been completed for a double-sided tape that can be suitably used in the manufacturing / assembling process of equipment and products.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the first invention of the present application, the release layer is mainly composed of polydimethylsiloxane having a vinyl group or a hexenyl group as a functional group, and the coating amount of the release layer is 0.07 g / m 2 as a solid content. ^The release liner is characterized by being ² or less. The main agent in the present invention is
Polydimethylsiloxane containing a vinyl group or a hexenyl group may be used, and although not particularly limited, addition reaction type silicone is usually used.

The release liner of the present invention is produced by laminating the above-mentioned main component on a release liner substrate.
The release liner substrate is not particularly limited,
Known release liner base materials that are commonly used can be used. Examples of the release liner base material include paper base materials such as glassine paper, coated paper, dust-free paper, cast coated paper, and polyethylene (P
E), laminated paper laminated with a thermoplastic resin such as polypropylene (PP), polyester film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polypropylene (OPP,
Examples thereof include polyolefin films such as CPP) and polymethylpentene, polycarbonate films, polyvinyl acetate films, and the like. Among them, PET film, PEN film, polypropylene (OPP, C
PP) film, PE laminated paper, PP laminated paper are suitable. The base paper of PE laminated paper or PP laminated paper is not particularly limited, but dust-free paper is most suitable when used in a clean room. The thickness of the release liner base material is not particularly limited and is appropriately selected depending on the application of the release sheet, but is usually 5 to 300 μm, preferably 10 to 200 μm.

The release layer in the present invention is prepared by a usual curing method. For example, a crosslinking agent is mixed with the main agent, diluted with a solvent such as a hydrocarbon compound such as toluene, hexane, heptane, ethyl acetate, methyl ethyl ketone, or a mixture thereof, and a platinum catalyst and a photosensitizer are added thereto. The coating solution prepared in this manner is a known coating method, for example, a Mayer bar coating method, a gravure coating method, a spray coating method, a spin coating method, or the like is applied to a base material, and a method of curing by heating in an oven is used. Can be used.

As the cross-linking agent, for example, polyorganosiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule can be preferably used, but polymethylhydrogensiloxane is particularly preferable. The amount of the crosslinking agent used is 0.1 to 100 parts by weight with respect to 100 parts by weight of the main agent.
The range of parts by weight is preferable, and the range of 0.3 to 50 parts by weight is particularly preferable. If the amount is less than 0.1 parts by weight, the main component may not be sufficiently cured, and if it is added in excess of 100 parts by weight, the effect corresponding to the addition amount cannot be obtained, which is not only economically disadvantageous, Further, it may cause a bad influence on the curability or a bad influence on the performance of the obtained release liner.

A platinum compound is usually used as the catalyst. Examples of the platinum compound include fine particle platinum, fine particle platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complex of chloroplatinic acid, palladium, rhodium catalyst and the like. . The amount of the catalyst used is based on the total amount of the main agent and the crosslinking agent.
The amount of metal is about 1 to 1000 ppm.

It is also possible to use a curing method in which a photosensitizer is further added and UV irradiation is carried out after heating in an oven. As the photosensitizer, α-hydroxyketones and / or α-diketone dialkyl acetals are preferably used. Here, as the α-hydroxyketone, for example, 2-hydroxy-1- (4-isopropylphenyl) -2-methylpropan-1-one, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
Preference is given to on, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methylpropan-1-one and 1-hydroxycyclohexylphenylketone. Examples of the α-diketone dialkyl acetals include benzyl dimethyl acetal (2,2-dimethoxy-1,2-diphenylethane-1-one) and benzyl diethyl acetal (2,2-diethoxy-1,2-diphenylethane). -1
-ON) can be preferably mentioned. These photosensitizers may be used alone or in combination of two or more. The photosensitizer is used in an amount of usually 0.01 to 10 parts by weight, preferably 0.1 to 2.0 parts by weight, based on 100 parts by weight of the total amount of the main agent and the crosslinking agent. If it is less than 0.01 parts by weight, the effect may not be sufficiently exhibited, and if it exceeds 10 parts by weight, the curability may be adversely affected or the performance of the release liner obtained may be adversely affected. is there.

In either case, it is preferable that the silicone is sufficiently cured. Further, a reaction inhibitor is usually preliminarily blended in the silicone release agent, but if the pot life of the coating liquid is insufficient, a reaction inhibitor may be added. Further, as the addition reaction type silicone, a solventless type and an emulsion type can be used in addition to the above solvent type.

The smaller the coating amount of the release layer of the present invention is, the less the migration of silicone is. On the other hand, the larger the coating amount is, the more the peeling force tends to increase. However, the coating amount is set depending on the kind of the adhesive used. Preferably. In conventional release liners, the coating amount of silicone is generally about 0.1 to 1.0 g / m ² ("Silicone Handbook" by Kunio Ito, published by Nikkan Kogyo Shimbun).
1990.519), in the present invention, the coating amount of the release layer needs to be 0.07 g / m ² or less in terms of solid content from the viewpoint of suppressing migration of silicone, and 0.0
It is preferably 5 g / m ² or less. Further, in consideration of the balance between suppression of silicone migration and release force, the coating amount is most preferably in the range of 0.005 g / m ^{2 to} 0.05 g / m ² .

In the present invention, the materials used as the main agent and the cross-linking agent are preferably substantially free of silicone resin, silicone gum made of non-functional polydimethylsiloxane, oil made of non-functional polydimethylsiloxane and the like. This is because if these are substantially contained, the desired low migration of silicone may be hindered.

As the adhesive which comes into contact with the release liner of the present invention, known pressure-sensitive adhesives, heat-sensitive adhesives and prepreg adhesives can be used. The pressure-sensitive adhesive is preferably an acrylic adhesive, and more preferably a specific acrylic adhesive that produces a small amount of gas when heated. The heat-sensitive adhesive may be a known one such as ethylene-vinyl acetate-based adhesive or acrylonitrile-based adhesive, and the prepreg adhesive may be epoxy-based adhesive or the like.

The amount of silicone transferred from the release liner to the adhesive surface is S when the silicone element (Si) and carbon element (C) on the adhesive surface are measured by XPS surface analysis method.
The i / Si + C (number of atoms) is preferably 3.0% or less. This is because the effect of the present invention may not be achieved if the silicone transfer amount exceeds 3.0%. The measurement conditions of the XPS surface analysis method are normal conditions for detecting Si and C.

The release liner of the present invention, as shown in FIG. 1, has a release liner base material 2 on which one side is subjected to a release treatment and a silicone release layer 1 is laminated, and as shown in FIG. It includes a mode in which both sides of the base material 2 are subjected to a release treatment and the silicone-based release layer 1 is laminated.

Next, a second invention of the present application is a double-sided tape having a release liner provided on both sides of an adhesive layer, wherein at least one release liner is the release liner according to the first invention. It is a double-sided tape. One surface of the double-sided tape according to the present invention has an essential constitutional requirement that the release liner is laminated,
The release liner on the other surface is not particularly limited. That is, a conventional silicone-based release liner, a release liner according to the present invention, or a silicone-free non-silicone release liner may be used. However, from the viewpoint of migration of silicone to the surface of the adhesive, it is preferable to use the release liner according to the present invention or a non-silicone release liner containing no silicone as the release liner on the other surface.

Specifically, as shown in FIG. 3, the release liner 3 of the present invention is arranged on one side of an adhesive layer having, for example, an acrylic adhesive 5 on both sides of a double-sided tape substrate 4. However, a mode in which the non-silicone release liner 6 is arranged on the other surface is preferable. Further, as shown in FIG. 4, a double-sided tape which does not have a double-sided tape base material and in which the pressure-sensitive adhesive 5 is sandwiched between the release liner 3 and the non-silicone release liner 6 of the present invention is also mentioned as a preferable embodiment.

As the non-silicone release liner, an ethylene-α-olefin copolymer elastomer,
Specifically, an ethylene-propylene copolymer elastomer, an ethylene-butene copolymer elastomer as a release layer, a low-density polyethylene or an ultra-low-density polyethylene as a release layer, or an ethylene-α-olefin copolymer A material obtained by blending an elastomer with low-density polyethylene, ultra-low-density polyethylene, or metallocene polyethylene can be used as the release layer. A non-silicone release liner having an alkyd release agent (fatty acid-modified alkyd) or a long-chain alkyl release agent (polycarbamate etc.) as a release layer can also be used.

[0023]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Evaluation test 1) Measurement of amount of transferred silicone The amount of transferred silicone on the surface of the adhesive was measured by the XPS method under the following conditions. Measurement conditions Measuring device Perkin Elmer ESCA5600 X-ray source Mg standard (15KV, 400W) Extraction angle 45 degrees Measuring time 3 minutes Measuring element Silicon (Si) and carbon (C) Silicon migration amount is 100 for the value of Si / Si + C It was multiplied and displayed in%.

2) Peeling force measurement According to JIS Z-0237, the peeling force when the release liner of the pressure-sensitive adhesive label was peeled by 180 degrees was measured with Tensilon. 3) Evaluation of Silicone Deposition on Semiconductor The release liner of the adhesive label was peeled off, and the adhesive surfaces of the adhesive sheet were bonded together. This was cut into a square of 20 × 1 cm, and 200 sets of the cut adhesive sheets were put in a stainless box having an internal size of 20 × 11 × 10 cm. Further, a Ga-As wafer having a very clean surface was placed in this box. Then, put a lid on the box, and place this box at 60 ° C, 25% R
It was left standing for 30 days under the condition of H. Then, from the box, Ga
-The As wafer was taken out, and the presence or absence of silicone was examined using a wavelength dispersive X-ray analyzer.

Example 1 A commercially available silicone [polydimethylsiloxane having a vinyl group as a functional group and substantially free of silicone resin, polydimethylsiloxane gum and silicone oil component] and polymethylhydrogensiloxane as a cross-linking agent. KS847; Shin-Etsu Chemical Co., Ltd. (silicone concentration 30%)] was diluted with a solvent, and a platinum catalyst [PL-50T; manufactured by the same company] was added at a ratio of 1 part by weight to 100 parts by weight of the silicone. It was used as a coating liquid. This coating solution was applied to a polyethylene terephthalate film having a thickness of 38 μm, which is a release liner substrate, using a Meyer bar so that the coating amount after drying would be 0.05 g / m ² . Curing was performed at 135 ° C. for 45 seconds to prepare a release liner. This release liner was coated on its silicone-coated side with a low gas-evolving acrylic pressure-sensitive adhesive [PL Shin (manufactured by Lintec Co., Ltd.) so that the coating amount after drying was 25 g / m ² and the temperature was 100 ° C. for 2 minutes. The adhesive label was dried and laminated with polyethylene terephthalate (PET) having a thickness of 50 μm from the upper side of the adhesive surface to give an adhesive label. For this sample, the amount of silicone transferred from the release layer to the pressure-sensitive adhesive surface was measured by XPS. The results are shown in Table 1.

Example 2 A pressure-sensitive adhesive label was prepared in the same manner as in Example 1 except that the coating amount of silicone after drying was 0.03 g / m ^2, and the amount of silicone transferred to the surface of the pressure-sensitive adhesive was measured by XPS. It was measured. The results are shown in Table 1.

Example 3 An adhesive label was prepared in the same manner as in Example 1 except that the release substrate was a polyethylene-laminated dustless paper, and the amount of silicone transferred to the surface of the adhesive was measured by XPS. The results are shown in Table 1.

Example 4 A commercially available silicone [polydimethylsiloxane having a hexenyl group as a functional group and substantially free of a silicone resin, a polydimethylsiloxane gum and a silicone oil component] and a polymethylhydrogensiloxane as a cross-linking agent. Silicone LTC-852-1 (heat / UV combined curing type) (manufactured by Toray Dow Corning Silicone (silicone concentration 30%))] 100 parts by weight is diluted with a solvent and a platinum catalyst [BY24-835 (manufactured by the same company)] is diluted. ] 2 parts by weight was added to obtain a coating solution. This coating solution was applied to a polyethylene terephthalate film having a thickness of 38 μm, which is a release liner substrate, using a Meyer bar so that the coating amount after drying would be 0.05 g / m ² . The curing is 240 w / c after heating at 90 ° C for 20 seconds.
The release liner was obtained by performing irradiation under the mUV lamp at 40 m / min. Then, an adhesive label was produced in the same manner as in Example 1, and the amount of silicone transferred to the adhesive surface was measured by XPS. The results are shown in Table 1.

Example 5 A double-sided tape base material was made of a polyester film having a thickness of 50 μm, and an acrylic adhesive [PL
Shin (manufactured by Lintec Co., Ltd.)]
A non-silicone release liner prepared by the method described in 0-59465 (a liner having a release layer made of a mixture of ethylene-α-olefin elastomer and low density polyethylene provided on dust-free paper) was laminated. Next, in the same manner as in Example 1, the same adhesive was applied to a silicone-based release liner,
This was laminated to prepare a double-sided tape, and the transfer amount of silicone on the pressure-sensitive adhesive surface was measured by XPS. The results are shown in Table 1.

Comparative Example 1 Silicone-based polyethylene terephthalate film liner, which is a commercially available release liner [Cerapeal BK (manufactured by Toyo Metallizing Co., Ltd., silicone coating amount 0.10 g / m 2
² )] was used, an adhesive label was prepared in the same manner as in Example 1, and the amount of silicone transferred to the adhesive surface was measured by XPS. The results are shown in Table 1.

[0031]

[Table 1] Note 1) Adhesive surface that was in contact with the silicone release liner Note 2) Adhesive surface that was in contact with the non-silicone release liner

The release liners of the present invention shown in Examples 1 to 5 showed no migration of silicone, and the release force was comparable to that of the conventional silicone release liners and was good. On the other hand, in the conventional silicone-based release liner shown in Comparative Example 1, migration of silicone was observed.

[0033]

The release liner of the present invention can significantly reduce the amount of transferred silicone as compared with the conventional silicone release liner without changing its performance and manufacturing cost. Further, in the double-sided tape, by using this novel release liner as at least one release liner, a double-sided tape suitable for electronic devices / parts can be manufactured.

[Brief description of drawings]

FIG. 1 is a release liner having a release layer on one side.

FIG. 2 is a release liner having release layers on both sides.

FIG. 3 is a double-sided tape having a release layer of the present invention on one side and a non-silicone release liner on the other side, which has a substrate.

FIG. 4 is a double-sided tape having a release layer of the present invention on one surface and a non-silicone release liner on the other surface, which has no base material.

[Explanation of symbols]

1; Silicone release layer 2; Release liner base material 3; Silicone release liner of the present invention 4; Double-sided tape base material 5: Acrylic adhesive 6; Non-silicone release liner

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F100 AK04 AK25G AK42 AK52A                       AK52C AK52H AT00B BA02                       BA03 BA04 BA05 BA06 BA07                       BA10A BA10C CA02A CA02C                       CB00B CB05 CC00A CC00C                       DG10 EH46 EJ05A EJ05C                       EJ08A EJ08C EJ54 GB90                       JL02 JL13 JL14A JL14C                       YY00A YY00C                 4J004 AA07 AA09 AA10 AB01 AB03                       CA06 CC02 DA02 DA04 DA05                       DB02 DB03 EA05 EA06 FA05

Claims (6)

[Claims] 1. A release layer is mainly composed of polydimethylsiloxane having a vinyl group or a hexenyl group as a functional group,
Moreover, the coating amount of the release layer is 0.07 g / m ² as solid content.
A release liner characterized by: 2. The release liner according to claim 1, which is obtained by curing polymethyl hydrogen siloxane as a crosslinking agent. 3. The release liner according to claim 1, which is substantially free of a silicone resin, a silicone gum composed of a non-functional polydimethylsiloxane, and an oil component composed of a non-functional polydimethylsiloxane. 4. The amount of silicone transferred from the release liner to the adhesive surface is S when measured by XPS surface analysis method.
The release liner according to any one of claims 1 to 3, wherein i / (Si + C) (number of atoms) is 3.0% or less. 5. A double-sided tape having a release liner provided on both surfaces of an adhesive layer, wherein at least one release liner is the release liner according to any one of claims 1 to 4. . 6. A double-sided tape having release liners on both sides of an adhesive layer, wherein one release liner is the release liner according to any one of claims 1 to 4 and the other release liner is a non-silicone type. A double-sided tape which is a release liner.