JP2801436B2 - Release film with antistatic performance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film having antistatic performance, and more particularly, to a release film using a polyester film having a specific antistatic layer on one or both sides thereof, and further using a curable silicone. The present invention relates to a release film provided with a layer to provide stable antistatic performance and excellent release properties.

[0002]

2. Description of the Related Art In recent years, with the wide application of pressure-sensitive adhesives and adhesives, the use of silicone-coated paper and films for protecting the pressure-sensitive adhesive surface has been remarkably growing.
It is indispensable for a protective layer such as a masking tape and a dicing tape in electric equipment. In addition, among materials such as plastics and rubbers, silicone-coated papers and films are applied to the molding of vinyl chloride, epoxy, polyurethane, polyester resin, etc., in order to maintain the moldability before curing and cooling and curing. ing. In addition, attention has been paid to the lubricity of silicone, and silicone-coated films having a low coefficient of friction on the surface have been widely used as slip sheets for audio cassettes.

[0003] The silicone used in these silicone-coated papers and films is generally required to prevent surface sticking and to minimize the migration of silicone to the backside. Therefore, as a silicone, polydimethylsiloxane having an -OH group at a terminal and-
Condensation reaction of H-group-containing polydimethylsiloxane (hydroxypolydimethylsiloxane) using an organotin catalyst to form a three-dimensional cross-linked structure, or polydimethylsiloxane and hydroxypolydimethylsiloxane with a vinyl group introduced into the terminal Are mainly used in which an addition reaction is carried out using an organic catalyst.

[0004] However, the silicone thin film thus formed has a drawback that charge is not leaked due to its silicone main chain bond and three-dimensional structure, and it is easily charged. Therefore, the film coated with the silicone thin film naturally has high chargeability and causes various obstacles. For example, when used as a mold film of various resins as a release film, the amount of peeling charge is large, adhesion of dust and the like occurs,
When used repeatedly, these may cause defects on the surface of the molded resin due to adhered foreign matter.

[0005]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to develop a release film having stable antistatic properties against temperature and excellent release properties, and as a result, have reached the present invention. It was done.

[0006]

That is, the present invention provides an antistatic layer using a tetraalkoxysilane and / or a partially hydrolyzed product thereof, which forms a charge transfer complex with a metal compound, on one or both surfaces of a plastic film. A release film having antistatic performance, characterized in that a release layer using a curable silicone is formed through the release film.

As the plastic film in the present invention, a transparent film (including a sheet) made of, for example, polystyrene, polymethyl acrylate, polycarbonate, polysulfone, polyester or the like can be preferably mentioned. Among these, a polyester biaxially stretched film is preferred. Polyester film can be easily controlled for transparency by adjusting the particle size and amount of lubricants, such as clay, kaolin, silica, calcium carbonate, etc., added and formed by the film forming stage, and the coating can be easily applied to the surface. In carrying out, solvent resistance, heat resistance,
It has the advantage of excellent mechanical properties.

[0008] The antistatic layer in the present invention uses a coating liquid of tetraalkoxysilane and / or a partial hydrolyzate thereof which forms a charge transfer complex with a metal compound, and is applied to one or both surfaces of a plastic film. Then, it is formed by heating and drying. In the heating and drying, the coating compound is hydrolyzed by moisture in the atmosphere, and the generated silanol causes a condensation reaction to form a three-dimensionally bonded silicon oxide film. These reactions are known and are shown schematically below.

[0009]

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The metal compound is preferably a divalent metal compound (eg, a halogen compound, an oxide, a hydroxide, a lower fatty acid salt, etc.) in view of the reaction yield of the complex and by-products. Mg, Ca, Sr, Mn, Co,
Ni, Fe, Cu, Zn, Cd, Hg, Sn, Pb, A
and the like. Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, and the like.

The complex formation reaction in the case of using an acetate is schematically shown as follows.

[0012]

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The tetraalkoxysilane forming a charge transfer complex with the metal compound and / or a partial hydrolyzate thereof can be obtained from the market.
C920, Colcoat EC851, and the like. These have an advantage that they are superior in long-term durability and stability of surface resistivity as compared with tetraalkoxysilane and / or a partial hydrolyzate thereof which does not form a charge transfer complex.

The release layer in the present invention is formed by using a coating liquid of a curable silicone, applying the coating liquid on the antistatic layer, and curing the coating. As the curable silicone, for example, any of a reaction system such as a condensation reaction system, an addition reaction system, a radical reaction system, an ultraviolet or electron beam curing system, and an alcohol addition reaction system of silyl isocyanate can be used. Can also be used. The curing reaction of silicone is as follows.

[0015]

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[0016]

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[0017]

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Electron beams have higher energy than ultraviolet rays.
A radical crosslinking reaction occurs without using an initiator as in the case of ultraviolet curing.

As the silicone of the condensation reaction system, for example, a polydimethylsiloxane having a terminal OH group and a polydimethylsiloxane having a terminal -H group (hydroxypolydimethylsiloxane) may be an organic tin catalyst (for example, an organic tin acylate catalyst). To form a three-dimensional crosslinked structure by a condensation reaction. Examples of the addition reaction type silicone include those which form a three-dimensional crosslinked structure by performing an addition reaction between polydimethylsiloxane having a vinyl group introduced at a terminal and hydroxypolydimethylsiloxane using a platinum catalyst. Examples of the UV-curable silicone include, for example, the most basic types which utilize the same radical reaction as ordinary silicone rubber crosslinking, those which are photocured by introducing an acrylic group, and those which decompose onium salts by ultraviolet rays to form strong acids. Examples thereof include those which are generated and crosslinked by opening the epoxy group with this, and those which are crosslinked by the addition reaction of thiol to vinyl siloxane. The alcohol-addition reaction type silicone utilizes a reaction between a silicon-functional silyl isocyanate and an alcohol. The silyl isocyanate reacts promptly with an alcohol but does not form a stable urethane compound, and the Si—N bond is cleaved to form a three-dimensional crosslinked structure.

The curable silicone has a degree of polymerization of 5
Desirable is about 0 to 50,000. Specific examples of these are DK-Q8-701, manufactured by Dow Corning.
-770, -778, -779; K manufactured by Shin-Etsu Chemical Co., Ltd.
S-774, -778, -841, -837, X-62
-2087, -2113, X-24-8301, X-2
2-343, -160C; T made by Toshiba Silicone Co., Ltd.
PR-6721, -6700, -6720, XS-56
-707, -619, YSR-3022, TUV600
0; SRX-211, -34 manufactured by Toray Silicone Co., Ltd.
5, SD-7220, -7223, -7229; SIC-003, SI-130, -2 manufactured by Matsumoto Pharmaceutical Co., Ltd.
20, -310, and -400.

In providing an antistatic undercoat layer on a plastic film and a cured silicone layer on the coating film, the coating method includes a bar coating method, a doctor blade method, a reverse roll coating method, a gravure roll coating method and the like. Can be used.

Drying and curing (thermal curing, ultraviolet curing, etc.) of the coating film can be performed individually or simultaneously. The simultaneous treatment is preferably carried out at 120 ° C. or higher, although it depends on the heat resistance (thermal dimensional stability) of the plastic film.

The release film of the present invention has the following features. 1) Due to the low surface energy of the overcoating layer of the cured silicon film, it has good releasability without adhering to various other substances. 2) The undercoat layer formed of a tetraalkoxysilane and / or a partial hydrolyzate thereof which forms a charge transfer complex with the metal compound can reduce the surface resistivity of the cured silicone overcoat layer surface to 1 × 10 ⁸ -1. × 10 ¹³ Ω /
It can be reduced to □, and charging failure can be avoided.

[0024]

The present invention will be described in more detail with reference to the following examples. The measurement of various characteristics of the film was performed by the following methods.

(1) Surface Specific Resistance The surface specific resistance is measured with a super insulation resistance meter (RM-214, manufactured by Huanghe Electric) conforming to ASTM D-257.

(2) Release Property A polyester adhesive tape (nit-31B) was stuck on the cured silicone overcoat layer, left to stand for 20 minutes after being pressed by a 2 kg pressure roller, and cut into a tape width (1 inch). It is peeled in the direction of 180 ° by an Instron type tensile tester, and the resistance value (g / inch) at that time is indicated.

(3) Coefficient of friction According to ASTM D-1894, the static friction (μs) and the dynamic friction coefficient (μd) between the treated surface and the non-treated plastic film are measured.

[0028]

Comparative Example 1 Colcoat P (trade name, manufactured by Colcoat Co., Ltd.), which is a partial hydrolyzate of polysiloxane, was diluted with isopropyl alcohol (IPA) to prepare a solution having a solid content of 1.5%.

This coating solution was applied to a polyester film (thickness 5
(0 μm) film was coated at a coating amount of 6 g / m ² (wet), and dried at a drying temperature of 120 ° C. and a residence time of 1 minute.

Further, 2 parts by weight of a curing agent [Toshiba Silicone Co., Ltd. CM-670] was added to 100 parts by weight of a curable silicone [Toshiba Silicone Co., Ltd. TPR-6700], and methyl ethyl ketone (MEK) and toluene were added. Dilute with a solvent to prepare a 1.5% solids solution,
A coating amount of 12 g on the film coated with Colcoat P
/ M ² (wet) and dried at a drying temperature of 140 ° C. for a residence time of 1 minute.

Table 1 shows the properties of the release film thus obtained.

[0032]

Example 1 Colcoat EC-620 (trade name), which is a partial hydrolyzate of tetraalkoxysilane containing a metal compound, was diluted with IPA to obtain a solid content of 1.
A 5% solution was prepared.

This coating solution was applied to a polyester film (thickness 5
(0 μm) film was coated at a coating amount of 6 g / m ² (wet), and dried at a drying temperature of 120 ° C. and a residence time of 1 minute.

Further, 2 parts by weight of a curing agent [trade name: CM-670, trade name of Toshiba Silicone Co., Ltd.] is added to 100 parts by weight of addition reaction type silicone [TPR-6700, trade name of Toshiba Silicone Co., Ltd.], and a solvent of MEK and toluene is used. The solution was diluted to prepare a solution having a solid content of 1.5%.
-920 g / m on a film coated with -920
² (wet) and dried at a drying temperature of 120 ° C. for a residence time of 1 minute.

Table 1 shows the characteristics of the obtained release film.

[0036]

Example 2 To 100 parts by weight of a condensation reaction type silicone [Toshiba Silicone Co., Ltd. trade name YSR-3022], 5 parts by weight of a curing agent [Toshiba Silicone Co., Ltd. trade name YC-6831] were added, and MEK, methyl isobutyl ketone was added. (MIB
K), and diluted with a solvent of xylene to prepare a solution having a solid content of 1.5%. In the same manner as in Example 1, this coating solution was coated on a film provided with the above-mentioned Colcoat EC-920.

Table 1 shows the properties of the release film thus obtained.

[0038]

Example 3 An isocyanate silicone [Matsumoto Pharmaceutical Co., Ltd. product name, Orgatics SIC-003], which is a mixture of a silane triisocyanate compound and polydimethylsiloxane, was used as the alcohol-reaction type silicone.
A was diluted with A to prepare a solution having a solid content of 1.5%. In the same manner as in Example 1, this coating solution was applied to the Colcoat EC-92.
0 was coated on the coated film.

Table 1 shows the characteristics of the obtained release film.

[0040]

Example 4 UV curable silicone [TUV6000 (Toshiba Silicone Co., Ltd.)] was coated on Colcoat EC-920 film coated in Example 1 to a thickness of 1 μm, and 8 KW (160 W / cm) ozone was generated. UV from a distance of 10cm in the high-pressure mercury lamp of 2000mj / cm ²
For 2 seconds to cure.

Table 1 shows the properties of the obtained release film.

[0042]

[Table 1]

As apparent from Table 1, the release film of the present invention is a film having both stable antistatic properties and release properties.

[0044]

According to the present invention, it is possible to provide a release film having a stable antistatic property against humidity and excellent release properties.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B32B 1/00-35/00 C08J 7/04 C09J 7/02-7/04 C09K 3/16

Claims (1)

(57) [Claims] A curable silicone is used on one or both surfaces of a plastic film via an antistatic layer using a tetraalkoxysilane and / or a partial hydrolyzate thereof forming a charge transfer complex with a metal compound. A release film having antistatic performance, wherein a release layer is formed.