JP2015124262A - Adsorption film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorption film which, even after a long time since being adhered to a glass surface as an adherend, does not leave a silicone resin fastened on the glass surface and can be easily repeeled.SOLUTION: Provided is an adsorption film having an adsorption layer laminated on at least one surface of a substrate film, the adsorption layer containing a silicone resin as a main component. The absorption layer is one obtained by coating and curing a silicone resin formed by curing a silicone composition by an addition reaction in the presence of a platinum catalyst, the silicone composition comprising a diorganopolysiloxane having at least two hexenyl groups in one molecule and an organohydrogensiloxane-diorganosiloxane copolymer.

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.

With the advancement of the information industry and electronics technology, display devices such as CRT displays, liquid crystal displays, and plasma displays have become widely used not only for televisions and personal computers, but also for copy machines, facsimiles, watches, telephones, etc. .

On the display screens in these display devices, there are protective films for protecting the surface from damage and scratches due to impact, and functional films for imparting functions such as antireflection, antistatic, antifouling, and antiglare. Affixing is done. Such various films have a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive, but the pressure-sensitive adhesive layer made of a pressure-sensitive adhesive usually used is the surface of the pressure-sensitive adhesive layer when peeled off. Since the shape of the adherend remains on the surface and does not restore to a flat state or takes time to restore, it is difficult to exhibit sufficient holding power when it is applied again.

On the other hand, the silicone rubber pressure-sensitive adhesive sheet in which a silicone rubber layer is provided on the surface of the transparent substrate film has an excellent cushioning property because the silicone rubber layer has an excellent cushioning property. Used in combination with. The silicone rubber layer of this silicone rubber pressure-sensitive adhesive sheet is usually blended with additives such as an adhesion improver in order to improve the adhesion between the base film and the polysiloxane, the catalyst, and the crosslinking agent. It is made of silicone rubber. (Patent Document 1).

However, since the adhesiveness is increased by blending such an additive, it is practically necessary to use a separator having an expensive fluorine-based release treatment applied to the silicone rubber layer. Moreover, at the time of pasting, the free silicone component may migrate to the adherend and contaminate the adherend.

On the other hand, a release film or sheet comprising a silicone composition for forming a solvent-type peelable cured film that forms a cured film with little silicone component migration to the back surface of the film has been proposed. The silicone composition includes an organopolysiloxane having at least two alkenyl groups in one molecule, an organohydrogenpolysiloxane having silicon-bonded hydrogen atoms bonded to at least three molecular chain side chains in one molecule, It contains a linear organohydrogenpolysiloxane having silicon-bonded hydrogen atoms at both ends of the molecular chain, a platinum-based catalyst and an organic solvent, and a photopolymerization initiator. (Patent Document 2).

In the prior art, a silicone rubber adhesive film provided with a silicone rubber layer made of a silicone resin on a base film, which can be reworked on or peeled off from an adherend having a smooth surface, is applied to an adherend such as glass. It was possible to some extent to reduce the migration of the silicone component to the adherend when pasted on. However, when pasted on a glass plate as an adherend for a long time, the SiH group derived from the unreacted silicone component in the silicone rubber reacts with the SiOH group on the glass surface over time, so that the silicone rubber layer becomes a glass surface. It has been found that there arises a problem of occurrence of a so-called silicone fixing phenomenon in which the silicone rubber layer remains on the glass surface. Until now, there have been no proposals for raising the above-mentioned problems and presenting effective solutions to the problems.

JP 2000-56694 A JP 2009-114285 A

The present invention has been made in view of the prior art as described above, and has sufficient adhesiveness and removability to an adherend such as a display screen at the time of sticking, and is repeatedly stuck. The unreacted silicone component in the adsorption layer does not migrate to the glass surface even when it is attached to the glass substrate of the display device as an adherend for a long time, and the adsorption layer over time It aims at providing the adsorption film which can be peeled again without adhering to a glass surface.

As a result of intensive studies to achieve the above object, the present inventor has been based on a silicone composition comprising a silicone containing an addition type organopolysiloxane having a specific functional group and an organohydrogensiloxane-diorganosiloxane copolymer. It has been found that the object can be achieved by forming an adsorption layer made of a silicone resin by applying a predetermined amount to a material film. The present invention has been completed based on such findings.

1st invention is the adsorption film formed by laminating | stacking the adsorption layer which has a silicone resin as a main component on the at least one surface of a base film, The said adsorption layer has at least 2 or more hexenyl group in 1 molecule. It is obtained by applying and curing a silicone resin obtained by curing a silicone composition containing a diorganopolysiloxane having an organohydrogensiloxane-diorganosiloxane copolymer in the presence of a platinum catalyst. It is an adsorption film characterized by being.

2nd invention is the adsorption film of 1st invention characterized by the thickness of the said adsorption layer being 5-100 micrometers.

The third invention relates to the molar ratio (A) of the number of moles of hexenyl group (A) of the diorganopolysiloxane having a hexenyl group to the number of moles of SiH group (B) of the organohydrogensiloxane-diorganosiloxane copolymer. ) / (B) is in the range of 0.4 to 1.5. The adsorption film according to any one of the first to second inventions.

According to a fourth aspect of the present invention, an anchor layer mainly composed of at least one resin selected from an acrylic resin, a polyester resin, and a urethane resin is provided between the base film and the adsorption layer. The adsorption film according to any one of the first to third inventions.

5th invention is an adsorption film in any one of 1st invention-4th invention, Comprising: It sticks and uses for the glass substrate of a display apparatus, It is an adsorption film for glass substrates characterized by the above-mentioned.

In the adsorption film of the present invention, the adsorption layer is added with a silicone composition containing a diorganopolysiloxane having at least two hexenyl groups in one molecule and an organohydrogensiloxane-diorganosiloxane copolymer. Since it is formed of a silicone resin that is cured by reaction, almost no SiH groups derived from free silicone components and unreacted organohydrogensiloxane-diorganosiloxane copolymer remain in the adsorption layer. Even when pasted on a glass substrate of a display device as an adherend for a long time, the unreacted silicone component in the adsorption layer does not migrate to the glass surface, and the adsorption layer adheres to the glass surface over time. It is possible to obtain an adsorption film that can be re-peeled without performing.

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 substrate may be appropriately selected according to the use, but is usually in the range of 5 to 400 μm, particularly 20 to 250 μm.

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.

(Silicone resin)
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. It is necessary to crosslink. For this purpose, a diorganopolysiloxane having a hexenyl group, which is transparent, excellent in heat resistance, compression set properties, low viscosity and liquid type, and an organohydro having a SiH group as a crosslinking agent under a platinum catalyst or the like. Preference is given to the use of addition-type liquid silicone resins which are thermally cross-linked by a hydroxyl reaction with a disiloxane-diorganosiloxane copolymer.

As such a silicone composition, a linear diorganopolysiloxane having a hexenyl group only at both ends of the molecular chain, a linear diorganopolysiloxane having a hexenyl group at both ends and side chains of the molecular chain, When a product obtained by crosslinking at least one selected from a branched diorganopolysiloxane having a hexenyl group only at the molecular chain end and a branched diorganopolysiloxane having a hexenyl group at the molecular chain end and side chain is used. good.

As one form of these diorganopolysiloxanes having hexenyl groups, linear polyorganosiloxanes having hexenyl groups only at both ends of the molecular chain are compounds represented by the following general formula (Formula 1).

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

A silicone comprising a linear polyorganosiloxane having hexenyl groups at both molecular chain terminals and side chains is a compound in which a part of R in the above general formula (Formula 1) is a hexenyl group. Silicone composed of a branched polyorganosiloxane having a hexenyl group only at the terminal is a compound represented by the following general formula (Formula 2). A silicone comprising a branched polyorganosiloxane having a hexenyl group at the molecular chain terminal and side chain is a compound in which a part of R in the following general formula (Formula 2) is a hexenyl group.

(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 hexenyl group may be different or of the same type. Specific examples include an alkyl group such as a methyl group, an ethyl group, and a propyl group, or bonded to a carbon atom of these groups. A monovalent hydrocarbon group excluding the same or different type of unsubstituted or substituted aliphatic unsaturated group in which part or all of the hydrogen atoms are substituted with a halogen atom, a cyano group, etc., preferably at least 50 mol% of which is methyl The diorganopolysiloxane may be a single group or a mixture of two or more types.

The hexenyl group-containing diorganopolysiloxane undergoes an addition reaction with the SiH group in the organohydrogensiloxane-diorganosiloxane copolymer component to form a polymer network. The amount of hexenyl groups in the polyorganosiloxane is at least 2 in one molecule, and the number of moles in 100 g of the diorganopolysiloxane is preferably 0.002 to 0.05, more preferably 0.00. 002 to 0.04. When the amount of hexenyl groups is less than 2 in one molecule, a polysiloxane network structure is not formed. Moreover, when the number of moles of hexenyl groups in the diorganopolysiloxane is less than 0.002, silicone adhesion tends to occur, and when it exceeds 0.05, the adhesion is insufficient.

Here, examples of the crosslinking agent used for the crosslinking reaction include organohydrogensiloxane-diorganosiloxane copolymers. A copolymer having at least three hydrogen atoms bonded to silicon atoms in one molecule is preferably used, and a copolymer having two ≡SiH bonds in the molecule is practically up to 50% by weight of the total amount. And the remainder preferably contains at least three ≡SiH bonds in the molecule.

The amount of the crosslinking agent used is a ratio between the number of moles of hexenyl groups (A) in the hexenyl group-containing diorganopolysiloxane component and the number of moles of SiH groups (B) in the organohydrogensiloxane-diorganosiloxane copolymer component, That is, (A) / (B) is in the range of 0.4 to 1.5, more preferably 0.5 to 1.0. When the amount of (A) / (B) is less than 0.4, crosslinking is insufficient, which may lead to an increase in adhesive force, a decrease in holding force, or an increase in silicone adhesion. On the other hand, when (A) / (B) exceeds 1.5, the crosslink density increases and sufficient adhesive strength and tack may not be obtained. Moreover, when the said upper limit is exceeded, the usable time of a composition may become short.

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

The shape of the commercially available silicone product according to the present invention includes a solventless type, a solvent type, and an emulsion type, but any type can be used. Especially, since the solventless type does not use a solvent, it is very advantageous in terms of safety, hygiene, and air pollution. However, even in the solventless type, as necessary to adjust the viscosity to obtain a desired film thickness, aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic carbonization such as hexane, heptane, octane, and isoparaffin are used. Hydrogen solvents, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and isobutyl acetate, ether solvents such as diisopropyl ether and 1,4-dioxane, or mixed solvents thereof are 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 adhesive film is used as the protective film for the display screen or the protective film for windows, the film thickness of the adsorption layer is at least 5 μm or more in order to ensure the shearing force in the adhesion surface direction of the adsorption layer with respect to the adherend. Usually, 5 to 200 μm is required. More preferably, it is 5-100 micrometers. Moreover, when using as a sealing material or a cushioning material, the film thickness of several 100 micrometers may be requested | required depending on the case. When the thickness is 5 μm or less, the shearing force in the adhesion surface direction of the functional film with respect to the adherend cannot be ensured, and the adsorbing film is easily peeled off from the adherend, particularly when applied for a long time.

(Anchor layer)
In the present invention, after the adhesion of the base film and the adsorbing layer is improved and the self-adhesive film is attached to the adherend, the adherend surface and the adsorbing layer surface are removed over time when the film is peeled off. An anchor layer may be provided between the base film and the adsorbing layer for the purpose of ensuring that the adhesive force of the substrate does not increase and can be peeled off smoothly and that no silicone residue is produced on the adherend.

Examples of the material for the anchor layer include polyester resins, acrylic resins, and urethane resins. Of these, acrylic resins are preferred, and acrylic polyol resins are particularly preferred from the viewpoint of antistatic properties and film 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 exceeds 5.0 μm, the anchor layer becomes inflexible and becomes a hard layer, resulting in poor adhesion to the base film.

As the coating 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.

A resin film separator can be bonded to the surface of the adsorption layer in order to prevent the adsorption layer surface from being contaminated or foreign matter adhered, or to improve the handling of the adsorption film.

The material of the adherend is generally glass, resin, metal, metal oxide or the like, and the surface of the adherend needs to be as smooth as possible. If the surface irregularities are large, it will be difficult for the silicone rubber layer to follow the irregularities, making it impossible to adhere.

The adsorption film of the present invention is useful when used as an adherend on a glass material, particularly a glass substrate of a display device. In the adsorption layer of the present invention, since the free silicone component and the SiH groups derived from the unreacted organohydrogensiloxane-diorganosiloxane copolymer hardly remain, the adsorption layer reacts with the SiOH groups on the glass surface to form the glass. It does not adhere firmly to the surface. Therefore, even when it is attached to the glass substrate of the display device as an adherend for a long time, the unreacted silicone component in the adsorption layer does not migrate to the glass surface, and the adsorption layer adheres to the glass surface over time. Re-peeling is possible without doing.

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 1-5, Comparative Examples 1-4)
The following anchor layer coating solution was applied with a gravure coater on one side of a plasma-treated polyethylene terephthalate film having a thickness of 100 μm and dried to form an anchor layer having a thickness of 0.2 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 to 5 and Comparative Examples 1 to 4 After the adsorption layer having the coating thickness in the table was provided on the anchor layer, the components in Table 1 were crosslinked in an oven at 150 ° C. for 100 seconds. An adsorption film of the present invention was produced.

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

(Evaluation method)
(Silicone transferability)
Evaluation procedure Clean the acrylic plate surface with a paper cloth soaked with ethanol.
2. The adsorbed film is bonded to the cleaned acrylic plate and allowed to stand at room temperature for 72 hours.
3. The attached adsorbing film is peeled off, and the water contact angle on the acrylic plate surface is measured.
Evaluation criteria It judged by the raise value of the contact angle from an untreated product (acrylic board). The water contact angle of the untreated acrylic plate was 64.7 °.
○: Increased value is less than + 5 °.
Δ: Increased value is + 5 ° or more and less than + 15 °.
X: Increased value is + 15 ° or more.

(Silicone fixing)
Evaluation procedure An adsorbent film was bonded to soda lime glass and allowed to stand at 50 ° C. and a humidity of 85% for 96 hours.
2. After the above laminated body was allowed to stand at room temperature for 2 hours, the adsorbed film was peeled off, and the silicone adhesion to the glass surface was visually confirmed.
Evaluation criteria ◎: No silicone sticking ○: Little silicone sticking ×: Silicone sticking

(Attachability / Bubble mixing)
The adsorption film was bonded to the acrylic plate, and the presence of bubbles was visually confirmed.
Evaluation criteria ◎: No air bubbles mixed ○: Almost no air bubbles mixed ×: Air bubbles mixed

Claims (5)

A diorganopolysiloxane having an adsorption film in which an adsorption layer mainly composed of a silicone resin is laminated on at least one surface of a base film, wherein the adsorption layer has at least two hexenyl groups in one molecule. And a silicone composition containing an organohydrogensiloxane-diorganosiloxane copolymer in the presence of a platinum catalyst, and a silicone resin formed by addition reaction, and is obtained by curing. Adsorption film. The adsorption film according to claim 1, wherein the adsorption layer has a thickness of 5 to 100 μm. Mole ratio (A) / (B) of mole number (A) of hexenyl group of diorganopolysiloxane having hexenyl group and mole number of SiH group (B) of organohydrogensiloxane-diorganosiloxane copolymer Is in the range of 0.4 to 1.5, the adsorption film according to any one of claims 1 to 2. An anchor layer mainly composed of one or more kinds of resins selected from acrylic resins, polyester resins, and urethane resins is provided between the base film and the adsorption layer. The adsorption film according to claim 1. It is an adsorption film in any one of Claims 1-4, Comprising: It sticks and uses for the glass substrate of a display apparatus, The adsorption film for glass substrates characterized by the above-mentioned.