JPH1044336A - Mold releasing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent adherence of dust or the like by reducing a release charg ing voltage of a surface to be released (release surface of the base film material) at the time of releasing a mold releasing film. SOLUTION: In the mold releasing film comprising a release layer containing silicone composition as a main body and provided at least on one side surface of a plastic film, the layer contains ion-conductive composition, and its surface specific resistance is 5×10<13> to 1×10<16> Ω/square. The thickness of the layer is normally in a range of 0.1 to 3μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film, and more particularly, to a release film having an effect of reducing peeling charge on a surface to be released.
The present invention relates to a release film that is effective in preventing dust from adhering to a release surface after the release film is peeled off.

[0002]

2. Description of the Related Art Conventionally, as a release film, a polyester film is provided with a silane coupling agent cross-linking layer and a silicone release layer is provided (Japanese Patent Laid-Open No. Sho 64-5).
No. 838), a curable silicone cured film provided on a plastic film via a thin layer of isocyanate silane and a specific surface resistance value within a specific range (Japanese Patent Application Laid-Open No. 3-106645). Release film in which a curable silicone release layer is formed via an antistatic layer using a tetraalkoxysilane forming a charge transfer complex with a metal complex and a hydrolyzate thereof (Japanese Patent Application Laid-Open No. H05-24156) ), A release film provided with a curable silicone layer via a conductive layer containing antimony-doped tin oxide (JP-A-6-344514), and the like.

[0003]

However, the above composition and composition have the following problems.

That is, a release film is generally used as a film for protecting the surface of an adhesive layer of acrylic, vinyl chloride, vinyl acetate, natural or synthetic rubber, etc., and is used after peeling off the release film in a practical stage. There are many cases. Among these, applications that dislike the attachment of dust due to charging of the release surface after release film release, such as the polarization substrate material, when dust adheres due to charging of the adhesive layer side after release, the performance after substrate assembly This can cause drawbacks. Therefore, it is desired that the surface to be separated be made non-charged after the release film is peeled off from the antistatic function of the release film itself.

However, in the above-mentioned prior art, since the surface of the silicone layer is present, the surface to be released is generally strongly negatively charged in the peeling step. Even if a layer having an antistatic function is interposed, the phenomenon is not caused. does not change. Although the above-described prior art is effective in making the release film non-chargeable, it does not make the release surface non-chargeable.

An object of the present invention is to provide a release film which has improved the above disadvantages and has a low charged voltage on the surface to be released after the release film is peeled off and which prevents adhesion of dust and the like.

[0007]

According to the present invention, there is provided a release film having a release layer mainly composed of a silicone composition provided on at least one surface of a plastic film, wherein the ionic conductive composition is contained in the release layer. The present invention relates to a release film which is contained and has a surface resistivity of more than 5 × 10 ¹³ Ω / □ and 1 × 10 ¹⁶ Ω / □ or less.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The plastic film of the release film in the present invention is not particularly limited as long as it is formed by molding a thermoplastic resin into a film. Nor is it limited.

Examples of the thermoplastic resin forming the plastic film include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polyamide, polycarbonate, polyvinyl chloride, polyurethane, acrylic, fluorine and polyphenylene. Sulfides and the like can be used. These may be homopolymers or copolymers. Of these, polyester films are preferably used in terms of mechanical strength, dimensional stability, and the like.

[0010] The thickness of the plastic film is not particularly limited and can be arbitrarily selected according to the intended use.
The range from m to 150 μm is preferably used.

Various additives such as a heat stabilizer, a weathering agent, a coloring agent such as an antistatic agent, a pigment and a dye, organic and inorganic fine particles, and the like are contained in the plastic film within a range not to impair the effects of the present invention. A plasticizer or the like may be added.

The surface of the plastic film on which the release layer is formed may be subjected to various treatments for improving the adhesion to the release layer, for example, in an arbitrary atmosphere such as air, nitrogen gas or carbon dioxide gas. Corona discharge treatment, chemical treatment, physical etching treatment, anchor treatment, or the like may be performed. In particular, anchor treatment using a silane coupling agent can be effectively used.

Next, the release layer of the present invention will be described. The release layer in the present invention is composed of a composition that reduces the amount of charge on the surface to be released (counterpart material) when used as a release film. Here, in order to have an original function of the release film, that is, a release function, it is essential to use a silicone-based composition as one component thereof. As the silicone to be used, any one of a condensation reaction type, an addition reaction type, a radical reaction type, and a curable one with heat, ultraviolet rays, electron beams or the like can be used. It is preferable to use a platinum compound catalyst when using addition type silicone among these, and to use an organotin catalyst or an organotitanium catalyst when using condensation silicone.

The above-mentioned silicone is obtained by applying a coating solution obtained by dissolving or dispersing the same using various solvents on a base film by any coating method such as gravure coating, reverse coating, bar coating and curing. Can be.

In order to reduce the amount of charge on the surface to be released, ie, the surface of the mating material from which the release film has been peeled, which is the gist of the present invention, an ionic conductive composition is added to the release layer composition. Is what you do. Here, the ionic conductive composition may be any composition of an anion, a cation, and a zwitterion, and a low molecular weight type surfactant,
Any of high molecular weight type and the like may be used. Alkyl sulfonate, alkyl benzene sulfonate, alkyl phosphate, polystyrene sulfonate as the anionic type, tetraalkylammonium salt, trialkylbenzylammonium salt, quaternary ammonium base-containing (meth) acrylate, quaternary as the cationic type Use of an ammonium base-containing maleimide copolymer, a quaternary ammonium base-containing methacrylimide copolymer, and an amphoteric type such as an alkyl betaine, an alkyl imidazolium betaine, a carbobetaine graft copolymer, and a polymer charge transfer type conjugate Can be.

Of these, the cationic type is particularly preferred in view of the effect of reducing the charged voltage. These ionic conductive compositions are mixed with a silicone composition having a release function to form a release layer, and the surface resistivity of the release layer surface layer exceeds 5 × 10 ¹³ Ω / □. It is necessary to be 1 × 10 ¹⁶ Ω / □ or less. That is, the present inventors add an ionic conductive material and lower the surface specific resistance, instead of a so-called conventionally known method for reducing a charged voltage by imparting conductivity. The specific resistance achieves its effect at a surface specific resistance much higher than 10 ¹⁰ Ω / □, which is generally a level for providing antistatic properties. Of course, even if an antistatic layer is provided on the release layer as in the above-mentioned known example and the surface specific resistance on the release layer side is lowered, the release surface after separation of the release film is still charged due to the difference in the charging sequence. You do it. Although the surface resistivity changes depending on the amount of the antistatic agent added, the present inventors demold the surface resistivity so as to be more than 5 × 10 ¹³ Ω / □ and not more than 1 × 10 ¹⁶ Ω / □. It has been found that by adding an ionic conductive composition to the layer, the charged voltage on the non-release surface (the surface of the opposite material from which the release film has been peeled) can be reduced. The amount of the ionic conductive composition to be added in such a range of the surface specific resistance is, for example, when the ionic conductive substance is added so that the surface specific resistance is 5 × 10 ¹³ Ω / □ or less. , 1
When the ion conductive material is reduced so as to exceed × 10 ¹⁶ Ω / □, there is a problem that the charged voltage on the parting surface becomes large. The effect of the present invention is exhibited only when added so that the resistance value falls within the range of the present invention. The amount of addition is not particularly limited as long as it is within the above-mentioned range of the surface resistivity, but is usually preferably 0.1 to 15 parts by weight, more preferably 0.2 to 1 part by weight, per 100 parts by weight of the silicone composition.
0 parts by weight, more preferably 0.5 to 5 parts by weight. In the present invention, the effect of reducing the peeling charge of the release surface is preferably such that the absolute value of the charged voltage of the release surface immediately after the release film peeling is preferably 5 kV or less, more preferably 3 kV or less.
It is more preferably 1 kV or less, and within this range, the effect of preventing adhesion of dust due to charging is exhibited. The silicone composition and the ionic conductive composition are preferably mixed on the surface of the release layer, and the more densely the mixed, the more effective. The effect may not be obtained if the release layer is separated in the thickness direction (so-called lamination state) or is roughly mixed.

The thickness of the release layer is not particularly limited and can be set arbitrarily, but is usually formed in the range of 0.1 to 3 μm.

Various additives such as heat stabilizers, weathering agents, antistatic agents, coloring agents such as pigments and dyes, organic and inorganic materials are contained in the release layer as long as the effects of the present invention are not impaired. Fine particles and a plasticizer may be added.

Next, an example of the method for producing a release film of the present invention will be described, but it is needless to say that the present invention is not limited to this. A coating composed of a coating composed of addition type silicone and a platinum catalyst and a quaternary ammonium salt type cationic antistatic agent was prepared on a biaxially oriented polyethylene terephthalate film having a thickness of 15 μm, and applied by a gravure coating method. After application, the composition is cured at 130 ° C. for 2 minutes to obtain a release film having a release layer laminated thereon. The release film thus obtained is usefully used as a cover film for various substrates, and can reduce the charge on the release surface after the release film is peeled off, thereby preventing dust from adhering.

[0020]

[Method for measuring characteristics and method for evaluating effects] The method for measuring characteristics and the method for evaluating effects in the present invention are as follows.

(1) Thickness of coating layer Transmission electron microscope (HU-12, manufactured by Hitachi, Ltd.)
Was used to observe the cross section of the release layer of the release film, and the thickness of the coating layer was determined from the photograph. The thickness was measured at an average value of 30 measurement points.

(2) Surface specific resistance value After the measurement sample was left in an atmosphere of 20 ° C. and 50% RH for 24 hours, a digital ultra-high resistance / microammeter R8340 (manufactured by Advantest Corporation) was used in the same atmosphere. The surface resistivity of the release layer surface was measured.

(3) Peeling stress An acrylic pressure-sensitive adhesive tape (Nitto polyester tape 31B, manufactured by Nitto Denko Corporation) having a width of 19 mm was attached to the release layer surface of the release film so as to have a length of 200 mm. (1 kg / cm). The stress when this adhesive tape was peeled at a pulling speed of 300 mm / min and a peel angle of 90 ° was determined. The measurement was an average value of 10 measurements.

(4) Peeling Charging Property The same adhesive tape was used in the same manner as in (3) above, and a laminated sample was prepared so as to have a width of 100 mm and a length of 150 mm, with the overlap of the adhesive tape being 2 mm. Place the adhesive tape of this sample in the direction of 180 degrees for 150
The adhesive tape was peeled at a stretch at a speed of mm / sec, and the charged voltage of the adhesive surface of the adhesive tape immediately after the peeling was measured using a STATILON TH-type static electricity measuring device (manufactured by Shisido Electrostatic Co., Ltd.). The measurement was performed at 20 ° C. and 50% RH. The measured value was an average value of ten measurements.

[0025]

Next, the present invention will be described based on examples.
It is not necessarily limited to this.

Example 1 A biaxially oriented polyethylene terephthalate film having a thickness of 50 μm was used as a base film, and one surface of the film was subjected to a corona discharge treatment in air. The following coating agent was applied to the treated surface so that the thickness after drying was 0.5 μm, and dried and cured at 130 ° C. for 2 minutes to prepare a release film.

Coating composition: 100 parts by weight of addition reaction type silicone (SD72 29 manufactured by Dow Corning Silicone Toray Co., Ltd.) 0.6 parts by weight of catalyst (SRX212CAT manufactured by Dow Corning Toray Silicone Co., Ltd.) Acrylic quaternary 0.5 parts by weight of ammonium salt type cationic antistatic agent These were dissolved and diluted in toluene to obtain a coating solution having a solid content of 5%. Table 1 shows the properties of the obtained release film.

Comparative Example 1 A release film was prepared in the same manner as in Example 1, except that the acrylic quaternary ammonium salt type antistatic agent was removed. Table 1 shows the results.

Examples 2 to 5, Comparative Example 2 0.2 part (Example 2), 1 part (Example 3), 5 parts (Example) of the acrylic quaternary ammonium salt type antistatic agent of Example 1. 4) A release film was prepared in the same manner except that 10 parts (Example 5) and 30 parts (Comparative Example 2) were used. Table 1 shows the results.

Example 6 The addition type silicone of Example 1 was replaced with a condensation type silicone (SRX29 manufactured by Dow Corning Toray Silicone Co., Ltd.).
A release film was prepared in the same manner except that the amount was changed to 0, 100 parts by weight and the catalyst: SRX242AC, 4 parts by weight. Table 1 shows the results.

Comparative Example 3 An antimony-doped tin oxide conductive film was provided on the film substrate of Example 1, and the addition type silicone of Example 1 (excluding the quaternary ammonium salt type cationic antistatic agent) was provided through the layer. A release film provided with was prepared. Table 1 shows the results.

[0032]

[Table 1]

[0033]

The release film obtained by the present invention is used as a protective film, and reduces the peeling voltage of the surface to be released (the release surface of the counterpart material) when the release film is peeled off. It has the effect of preventing the adhesion of water.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08K 5/00 C08K 5/00 C09D 183/00 PMM C09D 183/00 PMM C09J 9/02 JKV C09J 9 / 02 JKV // B32B 27/36 B32B 27/36 C08L 83/00 LRT C08L 83/00 LRT

Claims (3)

[Claims] 1. A release film having a release layer mainly composed of a silicone-based composition provided on at least one surface of a plastic film, wherein the release layer contains an ionic conductive composition and has a surface resistivity. Is more than 5 × 10 ¹³ Ω / □ and 1 × 10 ¹⁶ Ω / □ or less. 2. The release film according to claim 1, wherein the ionic conductive composition is a cationic antistatic agent. 3. The release film according to claim 1, wherein the absolute value of the charged voltage on the surface to be released immediately after the release film is peeled off is 5 kV or less.