JP2015140375A - Adsorption film - Google Patents

Abstract

An object of the present invention is to cut out an adsorbing layer at the cut end or to separate an adsorbing layer from a display surface such as a separator and liquid crystal at the time of punching of the adsorbing film and after adhering the adsorbing film to the display surface of liquid crystal or the like. To provide an adsorption film excellent in punching workability that does not cause floating.
In an adsorption film in which an adsorption layer mainly composed of a silicone resin is laminated on a base film, the breaking stress of the base film by a tensile test is 75 to 230 N / mm ^2. Adsorption film.
[Selection figure] None

Description

The present invention relates to an adsorbing film in which an adsorbing layer made of a silicone resin is provided on a base film that can be reworked to be adhered to or peeled off from an adherend having a smooth surface. They are protective films for flat panel displays used as display devices for devices, protective films for windows, and other sealing materials and cushioning materials used in a wide range of other industrial fields.

An adsorbing film provided with an adsorbing layer made of a silicone resin on a base film that can be reworked to be adhered to or peeled off from an adherend having a smooth surface is not limited to itself, and the adsorbing film has scratch resistance. By further providing functions such as UV blocking, electromagnetic blocking, conductivity, deodorizing, deodorizing, antibacterial, hydrophilic, antifogging, water repellency, thermal conductivity, ink acceptability, etc. Used in a wide field.

For example, when using an adsorption film with an adsorption layer made of silicone resin on a base film as a protective film for display screens such as liquid crystals, air bubbles are involved when affixing to an adherend having a smooth surface. Characteristics such as no generation of bubbles and good air bubble removal are required. In addition, it is necessary that the attached film does not shift or peel off over time. When the film is peeled off from the adherend, the adhesion between the adherend surface and the adsorption layer surface does not increase with time and is smooth. It is required to have a basic function such as being able to be peeled off and having no silicone residue on the adherend.

Conventionally, it is made of a laminate in which a pressure-sensitive adhesive layer made of silicone rubber or the like is laminated on at least one surface of a base film having a light transmittance of 80% or more for a film for the above use, and the light transmittance of the laminate is 80. % Or more of the protective film for display screens has been proposed. However, in the protective film for display screen, the adhesive protrudes from the end face of the cut part during punching, or the base film is deformed due to stress at the cut part, and the separator (release sheet) Punching workability was poor, for example, the pressure-sensitive adhesive layer was lifted off. In addition, when the film after punching is pasted on the display surface such as liquid crystal, the pressure-sensitive adhesive layer is lifted from the surface of the display such as liquid crystal due to the deformation of the base film during the punching process. It was found that this is not suitable for mass production of small-size display screen protective films. (Patent Document 1)

In order to improve the above punching processability, a specific amount of polyoxy is added to an acrylic copolymer containing a hydroxyl group-containing monomer as a copolymerization component and having a specific glass transition point (Tg) on the base film. A processing process protective film having a pressure-sensitive adhesive layer formed of a conductive composition comprising a dimethylsilicon compound having an alkylene group and an alkali metal ion and a pressure-sensitive adhesive composition containing a crosslinking agent having an isocyanate group has been proposed. . However, only by devising the pressure-sensitive adhesive layer, the sticking out of the pressure-sensitive adhesive and the adhesion from the surface of the display such as the separator (release sheet) and the liquid crystal during the above-described punching process and subsequent attachment to the display surface of the liquid crystal or the like. It has not been possible to solve the problems related to punching workability such as the floating of the agent layer. (Patent Document 2)

JP 2000-56694 A JP 2009-292958 A

The present invention allows rework to be applied to or peeled off from an adherend having a smooth surface, and also causes sticking of the adsorbing layer and separator (peeling) during punching and subsequent attachment to a display surface such as liquid crystal. It is an object of the present invention to provide an adsorbing film in which an adsorbing layer made of a silicone resin is provided on a base film, and the adsorbing layer is not lifted off from the display surface of a sheet or liquid crystal.

As a result of intensive studies, the present inventors have found that an adsorption film provided with an adsorption layer made of a silicone resin obtained by applying and thermally crosslinking an addition reaction type silicone composition on at least one surface of a plastic film having a specific breaking stress. It has been found that the adsorbing layer can be prevented from sticking out of the surface of the display, such as the separator (release sheet) and the liquid crystal, at the time of punching and after being attached to the display surface of the liquid crystal. The invention has been completed.

1st invention is the adsorption film which laminated | stacked the adsorption layer which has a silicone resin as a main component on a base film, The breaking stress by the tensile test of the said base film is 75-230 N / mm < ² >, It is characterized by the above-mentioned. It is an adsorption film.

In the second invention, the adsorption layer has a linear diorganopolysiloxane having vinyl groups only at both ends, a linear diorganopolysiloxane having vinyl groups at both ends and side chains, and a vinyl group only at the ends. A branched diorganopolysiloxane having at least one diorganopolysiloxane selected from branched diorganopolysiloxanes having vinyl groups at the ends and side chains, and an organohydrogenpolysiloxane having SiH groups, The adsorption film according to the first aspect of the invention is characterized in that an addition reaction type silicone composition that is thermally crosslinked by a hydroxyl reaction between the vinyl group and SiH group is applied and thermally crosslinked.

3rd invention is the adsorption film in any one of 1st invention-2nd invention, wherein the thickness of the said adsorption layer is 5-100 micrometers.

The adsorptive film of the present invention is stamped by providing an adsorbing layer made of a silicone resin obtained by applying an addition-reactive silicone composition and thermally cross-linking on at least one side of a plastic film having a specific breaking stress. Sometimes, the stress at the time of cutting is relieved in the punched portion, the deformation of the punched portion is reduced, and it is possible to suppress the sticking layer from sticking out or from the separator (release sheet). Further, even when the liquid crystal or the like is subsequently attached to the display surface, it is possible to continue to suppress the adsorption layer from floating from the display surface. Therefore, the present invention can be applied to mass production of a small-size display screen protective film as well as a large size.

Hereinafter, the adsorption film of the present invention will be described in more detail based on its constituent elements.

(Base film)
The base film used in the present invention is not particularly limited as long as it is a film made of various plastics. Examples include films made of polyolefin, polyester, polyamide, polycarbonate, triacetyl cellulose, fluororesin, polyphenylene oxide, polyimide, polyamideimide, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, etc. It is not limited. A polyester film and a polycarbonate film are preferable from the viewpoints of handleability and cost at the time of thermal crosslinking of silicone rubber. From the viewpoint of transparency, a polyester film, particularly polyethylene terephthalate is preferable. The thickness of the base film is preferably in the range of 50 to 125 μm in consideration of the punching workability as an adsorption film.

When the thickness of the base film is less than 50 μm, the handleability at the time of attaching the adsorption film is deteriorated. On the other hand, if the thickness of the substrate film exceeds 125 μm, the breaking stress due to the tensile test becomes large, and the adsorption layer tends to float from the separator (release sheet) during the punching process.

(Measurement method of breaking stress)
In the measurement of the breaking stress by the tensile test of the base film of the present invention, a 10 mm wide × 150 mm long sample is cut out from the base film, and the sample is measured so that the sample measurement site is 10 mm wide × 100 mm long (extension direction). The sample is set and stretched at a tensile rate of 200 mm / min using a tensile tester (manufactured by Shimadzu Corporation, Autograph) in an environment of 25 ° C. and 50% RH, and the breaking stress (N / mm ² ) is measured.

As the breaking stress by the tensile test of the base film, 75 to 230 N / mm ² is used in consideration of the punching workability as an adsorption film. When the breaking stress by the tensile test of the base film is less than 75 N / mm ² , at the time of punching, the adsorbing film is cut at a place other than the punched portion, or the handleability at the time of pasting is deteriorated. . On the other hand, when the breaking stress by the tensile test of the base film exceeds 230 N / mm ² , the adsorption layer tends to float from the separator (release sheet) during punching.

The surface of the base film may be subjected to corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, flame treatment, or may be provided with an anchor layer or the like as necessary. As a method for laminating the anchor layer or the like, either a so-called in-line method for laminating at the time of film formation or a so-called off-line method for laminating on the formed film may be used.

(Adsorption layer)
The properties of the silicone resin used in the adsorption layer of the present invention are high in transparency, have flexibility like rubber, and the surface of the adsorption layer is also along the adherend surface with respect to the adherend surface. Is required. Further, when peeling, it is required to be easily peeled with a small peeling force. In addition, in order to provide a crosslinked adsorption layer only by coating and heat treatment at least 5 μm in thickness and without using a basis weight processing method, in the curing reaction of the silicone composition, at a low temperature of not more than 150 ° C. in a short time. Cross-linked, transparent, heat-resistant, excellent compression set, low viscosity, liquid type, polyorganosiloxane with vinyl group and organohydrogenpolysiloxane with SiH group as cross-linking agent under platinum catalyst It is preferable to use an addition-type liquid silicone resin that is thermally crosslinked by a hydroxyl reaction with.

As such a silicone resin, linear polyorganosiloxane having vinyl groups only at both ends, linear polyorganosiloxane having vinyl groups at both ends and side chains, and vinyl groups only at the ends It is preferable to use a product obtained by crosslinking at least one polyorganosiloxane selected from a branched polyorganosiloxane and a branched polyorganosiloxane having vinyl groups at the terminals and side chains.

One form of these polyorganosiloxanes is a linear polyorganosiloxane having vinyl groups only at both ends, and is a compound represented by the following general formula (Formula 1).

(In the formula, R represents the following organic group, and n represents an integer.)

(In the formula, R represents the following organic group, and m represents an integer.)

The organic group (R) bonded to the silicon atom other than the vinyl group may be different or of the same type. Specific examples include alkyl groups such as methyl, ethyl and propyl groups, and aryl groups such as phenyl and tolyl groups. Or a monovalent hydrocarbon group other than the same or different unsubstituted or substituted aliphatic unsaturated group in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms, cyano groups, or the like. The diorganopolysiloxane may be used singly or as a mixture of two or more, preferably at least 50 mol% of which is a methyl group.

The linear polyorganosiloxane having vinyl groups at both ends and side chains is a compound in which a part of R in the above general formula (Formula 1) is a vinyl group. The branched polyorganosiloxane having a vinyl group only at the terminal is a compound represented by the above general formula (Formula 2). The branched polyorganosiloxane having vinyl groups at the terminals and side chains is a compound in which a part of R in the above general formula (Formula 2) is a vinyl group. As the shape, a linear, branched or cyclic shape can be used.

In the present invention, a known crosslinking agent may be used for the crosslinking reaction in combination with the above polyorganosiloxane having a vinyl group. Examples of the crosslinking agent include organohydrogenpolysiloxane having a SiH group in the molecule. The organohydrogenpolysiloxane preferably has at least three hydrogen atoms bonded to silicon atoms in one molecule, but for practical purposes, the total amount of those having two ≡SiH bonds in the molecule. It is preferable that the remaining amount be at least 3 ≡SiH bonds in the molecule.

The organic group (R) bonded to the silicon atom other than the hydrogen atom may be different or the same, and specific examples thereof include an alkyl group such as a methyl group, an ethyl group and a propyl group, and an aryl group such as a phenyl group and a tolyl group. Or a monovalent hydrocarbon group other than the same or different unsubstituted or substituted aliphatic unsaturated group in which part or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms, cyano groups, or the like. Preferably, at least 50 mol% of them is a methyl group.

The platinum-based catalyst used for the crosslinking reaction of the addition reaction type silicone composition may be a known one, and includes chloroplatinic acid such as chloroplatinic acid and chloroplatinic acid, alcohol compounds of chloroplatinic acid, Examples thereof include chain salts of aldehyde compounds or chloroplatinic acid and various olefins. The adsorption layer subjected to the crosslinking reaction has flexibility such as silicone rubber, and this flexibility facilitates the close contact with the adherend.

Commercially available shapes of the silicone composition according to the present invention include a solventless type, a solvent type, and an emulsion type, and any type can be used. Among these, the solventless type is very advantageous in terms of safety, hygiene, and air pollution because it does not use a solvent, but even in the solventless type, as a viscosity adjustment for obtaining a desired film thickness, As needed, aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, heptane, octane and isoparaffin, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate and isobutyl acetate An ester solvent, an ether solvent such as diisopropyl ether or 1,4-dioxane, or a mixed solvent thereof is used.

As described above, the properties of the adsorbing layer are required to have a softness like rubber and follow the irregularities on the surface of the adherend to ensure adhesion when adhered to the adherend. For example, when an adsorption film is used as a protective film for the display screen or a protective film for windows, the thickness of the adsorption layer is 5 μm to 100 μm in order to secure a shearing force in the adhesion surface direction of the adsorption layer with respect to the adherend. Are preferred. When the thickness of the adsorbing layer is less than 5 μm, a shearing force in the direction of the adhesion surface of the functional film to the adherend cannot be secured, and the adsorbing film is easily peeled off from the adherend, particularly when applied for a long time. In addition, when the thickness of the adsorption layer exceeds 100 μm, the adsorption layer tends to protrude from the end face of the punched portion during the punching process.

(Anchor layer)
In the present invention, the adhesion force between the adherend surface and the adsorption layer surface over time is improved when the film is peeled off after the adhesion film is adhered to the adherend and the adhesion film is improved. An anchor layer may be provided between the base film and the adsorbing layer for the purpose of preventing peeling and smooth peeling and no silicone residue on the adherend.

Examples of the material for the anchor layer include acrylic resin, polyester resin, and urethane resin. The polyester resin is preferably an acrylic-modified or urethane-modified one, and a special acrylic polyol resin is preferable from the viewpoint of coating properties.

In addition, an antistatic agent can be added to the anchor layer as an additional compounding material to impart an antistatic function. Nonionic polyoxyethylene alkyl ether, polyoxyethylene alkylphenol, polyoxyethylene alkylamine, polyoxyethylene alkylamide, fatty acid polyethylene glycol ester, fatty acid sorbitan ester, polyoxyethylene fatty acid sorbitan ester, fatty acid glycerin ester, alkyl polyethyleneimine, etc. Can be mentioned. An acrylate compound having ethylene oxide as a skeleton can also be used. Polyaniline, polypyrrole, polythiophene, poly3,4-ethylenedioxythiophene, and derivatives thereof can be used as the conductive polymer. As the metal oxide, antimony-doped tin oxide (ATO), tin-doped indium oxide (ITO), aluminum-doped zinc oxide, antimony suboxide, or the like can be used.

The thickness of the anchor layer is in the range of 0.1 to 5.0 μm, more preferably in the range of 0.15 to 3.0 μm. When the thickness of the anchor layer is less than 0.1 μm, the thermally crosslinked adsorption layer is easily detached from the base film. Furthermore, the antistatic performance is not stable. On the other hand, when the thickness of the anchor layer exceeds 5.0 μm, the anchor layer becomes inflexible and becomes a hard layer, resulting in poor adhesion to the base film.

As an application method of the anchor layer coating solution and the adsorption layer coating solution, known methods such as a multi-stage roll coater represented by a three-offset gravure coater and a five-roll coater, a direct gravure coater, a bar coater, and an air knife coater are available. Used as appropriate.

In the adsorption film of the present invention, a separator made of a resin film (release sheet) can be bonded to the adsorption layer surface in order to prevent the surface of the adsorption layer from adhering to the foreign matter and to improve the handling of the adsorption film. The separator (release sheet) is made of a highly releasable resin film made of polyethylene terephthalate, polyethylene polyethylene, polypropylene, or the like, and if desired, a surface coated with a release agent such as a silicone material. Subsequent to the above-described process, cutting into any appropriate shape or size is performed. The formed adsorption film can be used after being cut or punched into a desired shape for further use.

The substrate film surface on the opposite side of the adsorption layer of the adsorption film of the present invention has scratch resistance, ultraviolet ray shielding property, electromagnetic wave shielding property, conductivity, deodorizing property, deodorizing property, antibacterial property, hydrophilic property, antifogging. A functional layer having properties such as water repellency, water repellency, and thermal conductivity can be further provided.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example. In the examples, “parts” indicates parts by weight unless otherwise specified.

(Examples 1-4, Comparative Examples 1-3)
The following anchor layer coating solution was applied with a gravure coater on one side of each substrate film (polyethylene terephthalate film) having the thickness described in Table 1 to form an anchor layer having a thickness of 3.0 μm. .

(Anchor layer coating solution)
20 parts of acrylic polyol resin (manufactured by Toray Fine Chemicals, Cotax LH455, solid content: 50%)
27 parts of polythiophene (manufactured by Shin-Etsu Polymer, Sepulzida OC-SC100, solid content: 3%)
MEK 40 parts Toluene 13 parts

(Examples 1-4, Comparative Examples 1-3)
On the anchor layer, the following adsorbing layer coating liquid components are provided with adsorbing layers having respective coating thicknesses (after drying) described in Table 1, and then crosslinked in an oven at 150 ° C. for 100 seconds. Thus, the adsorption films of Examples 1 to 4 of the present invention and the adsorption films of Comparative Examples 1 to 3 were produced.

(Adsorption layer coating solution)
Linear polyorganosiloxane having vinyl groups only at both ends 68.3 parts (solvent-free) / (Mw: 80,000)
Organohydrogenpolysiloxane 0.7 parts (solvent-free type) / (Mw: 2,000)
Platinum catalyst (trade name: PL-56, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part Toluene 30.0 parts

The evaluation results of each example and comparative example are shown in Table 1, and each evaluation method is shown below.

(Evaluation method)
(Measurement method of breaking stress)
The measurement of the breaking stress by the tensile test of the base film is to cut out a 10 mm wide × 150 mm long sample from the base film, and set the sample so that the sample measurement site is 10 mm wide × 100 mm long (extension direction), When the sample is stretched at a tensile rate of 200 mm / min using a tensile tester (manufactured by Shimadzu Corp., Autograph) in an environment of 25 ° C. and 50% RH, and when the sample breaks (at least when a crack occurs from a part) The breaking stress (N / mm ² ) was measured. Moreover, about the measurement of the breaking stress by the tensile test of an adsorption film, it carried out previously according to the measuring method of said base film.

(Punching process)
After adhering a polyethylene terephthalate film having a thickness of 25 μm to the adsorption layer surface of each of the produced adsorption films and leaving it in an environment of 25 ° C. and 50% RH for 24 hours,
Using a punching machine, a 60 mm wide × 125 mm long sample was punched at a pressure of 20 Kgf / cm to produce an adsorption film with a separator.

(Adsorption layer protruding)
The cut end surface of each of the punched samples was visually observed, and the protrusion of the adsorption layer was evaluated according to the following criteria.
Evaluation criteria for sticking out of adsorbing layer ◎: Adsorbing layer does not protrude from end face of base film ○: Adsorbing layer hardly protrudes from end face of base film ×: Adsorbing layer protrudes from end face of base film

(Adsorption layer floating)
The cut end face of each of the above punched samples was visually observed, and the float of the adsorption layer was evaluated according to the following criteria.
Evaluation standard of adsorption layer float ◎: Separator (release sheet) and adsorption layer are completely adhered ○: Separator (release sheet) and adsorption layer are hardly peeled ×: Adsorption layer from separator (release sheet) Peeled off

(Reworkability)
The prepared adsorbing film was cut to a width of 25 mm, and the adsorbing layer of the adsorbing film was pressure-bonded by reciprocating a 2 kg roller once on an acrylic plate having a thickness of 2 mm. Next, using a tensile tester, peeling was performed at a peeling angle of 180 ° and a peeling speed of 1200 mm / min, and the acrylic plate peeling force (mN / 25 mm) of the adsorption film was measured.
Evaluation criteria for reworkability ◎: Acrylic plate peeling force of 25 mN / 25 mm or more and less than 150 mN / 25 mm ○: Acrylic plate peeling force of 150 mN / 25 mm or more and less than 400 mN / 25 mm ×: Acrylic plate peeling force of less than 25 mN / 25 mm, 400 mN / 25mm or more

Claims (3)

An adsorptive film in which an adsorbing layer containing a silicone resin as a main component is laminated on a base film, wherein the base film has a breaking stress of 75 to 230 N / mm ² by a tensile test. The adsorbing layer is a linear diorganopolysiloxane having vinyl groups only at both ends, a linear diorganopolysiloxane having vinyl groups at both ends and side chains, and a branched diorganoorganism having vinyl groups only at the ends. Containing at least one diorganopolysiloxane selected from polysiloxane, branched diorganopolysiloxane having vinyl groups at the terminals and side chains, and polyorganohydrogensiloxane having SiH groups, and the vinyl group The adsorptive film according to claim 1, which is obtained by applying and thermally crosslinking an addition reaction type silicone composition that is thermally crosslinked by a hydroxyl reaction with a SiH group. The thickness of the said adsorption layer is 5-100 micrometers, The adsorption film in any one of Claims 1-2 characterized by the above-mentioned.