WO2016121875A1 - Optical surface protective film with separator - Google Patents

Abstract

Provided is an optical surface protective film with a separator comprising: a polyester film on one surface of an adhesive layer; and the separator on the surface opposite the polyester film of the adhesive layer; wherein an Si-K alpha x-ray strength in a fluorescent x-ray of the surface of the adhesive layer after peeling the separator is at most 2.5 kcps; and wherein a peeling force of the separator with respect to the optical surface protective film is at most 0.5 N/50mm in a tension speed of 0.3 m/minute. The optical surface protective film with the separator can prevent the phenomenon of other layers provided on the surface of the adherend, such as an interlayer filler (layer), from peeling easily after peeling the surface protective film from the adherend.

Description

Optical surface protection film with separator

The present invention relates to an optical surface protective film with a separator.

The optical surface protective film with a separator of the present invention is an optical member such as glass, polarizing plate, wavelength plate, retardation plate, optical compensation film, reflection sheet, brightness enhancement film, and transparent conductive film used for liquid crystal displays. It is useful as an optical surface protective film used for the purpose of protecting the surface.

Conventionally, in order to prevent scratches on the surface of optical members, electronic members, etc. during processing, assembly, inspection, transportation, etc., a surface protective film is generally adhered to the exposed surface of the member. The surface protective film is composed of a base film and an adhesive layer. If necessary, a separator (release film or release film) is provided on the adhesive surface for the purpose of protecting the adhesive layer before sticking (use). (Also referred to as a liner) is bonded together (Patent Document 1). The surface protective film with a separator is attached to an optical member that is an adherend after the separator is peeled off.

The attached surface protective film may be provided with a layer having another function (another layer) on the surface of the optical member after peeling off after being peeled off from the optical member when it is no longer needed. Yes (Patent Document 2).

JP2012-224811 JP2014-208756

However, depending on the state of the surface of the optical member (adhered body) after the surface protective film is peeled off, other layers may be peeled off from the optical member due to poor wettability or adhesion to other layers. There was a problem that the product became defective. In particular, when a surface protective film with a separator is used, another layer (for example, an interlayer filler (layer) provided on an adherend (for example, a glass surface constituting an optical member) after peeling the optical surface protective film. )) Has a problem that it is easily peeled off. Therefore, when other layers such as an interlayer filler (layer) are provided on an adherend such as a glass surface after the surface protective film is peeled off, an optical surface protective film with a separator that can secure a state in which it is difficult to peel off. Development is required.

The object of the present invention is to protect the optical member as an adherend from dirt and scratches, and to provide an interlayer filling provided on the adherend surface after the surface protective film is peeled from the adherend. It is to provide an optical surface protective film with a separator that can prevent a phenomenon that other layers such as an agent (layer) are easily peeled off.

In light of the above circumstances, the present inventors have conducted intensive research. In the optical surface protective film with a separator, the adhesive layer after peeling the separator is peeled off after being attached to an adherend such as glass. Then, the adhesive layer component remains on the adherend and the surface of the adherend is contaminated, so that other layers such as an interlayer filler (layer) provided on the adherend are peeled off. I thought it would have influenced the ease. Therefore, when using an optical surface protective film with a separator having a specific parameter, since the influence of contamination of the surface of the adherend after peeling the optical surface protective film can be reduced compared to the conventional case, for example, The present inventors have found that an optical surface protective film with a separator that can prevent peeling of other layers such as an interlayer filler (layer) can be provided.

That is, the present invention is an optical surface protective film with a separator having a polyester film on one side of the pressure-sensitive adhesive layer and a separator on the opposite side of the polyester film of the pressure-sensitive adhesive layer, after the separator is peeled off The surface of the pressure-sensitive adhesive layer has a fluorescent X-ray Si-Kα ray intensity of 2.5 kcps or less, and the peeling force of the separator with respect to the optical surface protective film is 0.5 N at a tensile speed of 0.3 m / min. It is related with the optical surface protection film with a separator which is / 50 mm or less.

In the optical surface protective film with a separator of the present invention, the separator has a release layer and a substrate, and the release layer contains a long-chain alkyl-based material and / or an aliphatic carboxylic acid ester. It is preferably formed from an agent composition.

In the optical surface protective film with a separator of the present invention, the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer (A) and an aliphatic polyisocyanate-based crosslinking agent (B). The (meth) acrylic polymer (A) contains at least an alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms and a hydroxyl group-containing (meth) acrylic monomer as a monomer component, and has a glass transition temperature. Is 2-50 parts by weight of the hydroxyl group-containing (meth) acrylic monomer with respect to 100 parts by weight of the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms. Is preferred.

The optical surface protective film with a separator of the present invention preferably contains 1 to 30 parts by weight of the aliphatic polyisocyanate crosslinking agent (B) with respect to 100 parts by weight of the (meth) acrylic polymer (A). .

In the optical surface protective film with a separator of the present invention, it is preferable that the pressure-sensitive adhesive composition further contains a catalyst (C) having iron or tin as an active center.

In the optical surface protective film with a separator of the present invention, 0.002 to 0.5 weight of the catalyst (C) having iron or tin as an active center with respect to 100 weight parts of the (meth) acrylic polymer (A). It is preferable to contain a part.

The optical surface protective film with a separator of the present invention is excellent in the peelability between the optical surface protective film and the separator, and the optical surface protective film after the separator is peeled off is excellent in the peelability to the adherend. When the surface protective film for optics is peeled off, the influence of contamination of the surface of the adherend by the pressure-sensitive adhesive layer is small, so that other layers such as an interlayer filler (layer) provided on the adherend thereafter are attached. It is useful because it can be prevented from peeling off.

It is a typical sectional view showing an example of 1 composition of an optical surface protection film with a separator concerning the present invention.

Hereinafter, embodiments of the present invention will be described in detail.

<Overall structure of optical surface protective film with separator>
The optical surface protective film of the present invention is an optical component (for example, glass used for a liquid crystal display, a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a reflective sheet, a brightness enhancement film, a transparent conductive film, etc. Optical surface protective film that protects the surface of optical components during processing and transport of optical components), and is generally referred to as an optical adhesive sheet, optical adhesive tape, optical adhesive label, optical adhesive film, etc. It is a thing of the form. The pressure-sensitive adhesive layer in the optical surface protective film is typically formed continuously, but is not limited to such a form, and is formed in a regular or random pattern such as a dot or stripe. It may be a pressure-sensitive adhesive layer. The optical surface protective film may be in the form of a roll or a single wafer.

A typical configuration example of the optical surface protective film with a separator of the present invention is schematically shown in FIG. This optical surface protective film 3 with a separator is a form in which a separator 1 and an optical surface protective film 2 are laminated. The separator 1 includes a substrate 11 and a release layer 12, the optical surface protective film 2 includes a polyester film 22, and an adhesive layer 21 provided on one surface thereof, and the lamination is performed with the release layer 12 and the adhesive layer. The agent layer 21 is bonded together. After the separator 1 is peeled off, the optical surface protective film 3 with a separator is an optical member (an object to be protected, for example, glass used for a liquid crystal display, a polarizing plate, a wave plate, a retardation, etc.). It is used by being attached to the surface of an optical component such as a plate, an optical compensation film, a reflection sheet, a brightness enhancement film, and a transparent conductive film, and is peeled off from the optical member when it becomes unnecessary. Further, the optical surface protective film 3 with a separator has a pressure-sensitive adhesive layer 2 on both sides of the polyester film 22, or has an antistatic layer on the opposite side of the surface of the polyester film 22 to which the pressure-sensitive adhesive layer 2 is attached. Is mentioned.

<Optical surface protective film>
The optical surface protective film of the present invention comprises a polyester film and an adhesive layer.

<Polyester film>
The polyester film of the present invention includes a polymer material (polyester resin) having a main skeleton based on an ester bond such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate as a main resin component. Can be mentioned. The polyester film is excellent in optical properties and dimensional stability, but has the property of being easily charged as it is.

The resin material constituting the polyester film may contain various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, and a colorant (pigment, dye, etc.) as necessary. The first surface of the polyester film may be subjected to known or common surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer. Such a surface treatment can be, for example, a treatment for improving the adhesion between the polyester film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer). A surface treatment in which polar groups such as hydroxyl groups (—OH groups) are introduced on the surface of the polyester film can be preferably employed. Further, the second surface of the polyester film may be subjected to the same surface treatment as described above, and an adhesive layer or an antistatic layer may be provided.

The surface protective film for optics of the present invention can be provided with an antistatic function by providing the antistatic layer on the surface opposite to the surface to which the pressure-sensitive adhesive layer of the polyester film is attached. Moreover, you may use the polyester film by which antistatic treatment was made beforehand. It is preferable to use the polyester film because charging is suppressed when the separator is peeled off or when the pressure-sensitive adhesive layer is peeled off from the optical member as an adherend. In addition, there is no restriction | limiting in particular as a method to provide an antistatic function, A conventionally well-known method can be used, for example, antistatic resin which consists of an antistatic agent and a resin component, a conductive polymer, and a conductive substance. Examples thereof include a method of applying a conductive resin, a method of depositing or plating a conductive material, a method of kneading an antistatic agent, and the like.

The thickness of the polyester film is usually about 5 to 200 μm, preferably about 10 to 100 μm. When the thickness of the polyester film is within the above range, it is preferable because the workability of bonding to an optical member as an adherend and the workability of peeling from the optical member are excellent.

<Adhesive layer>
The pressure-sensitive adhesive layer of the present invention is formed from a pressure-sensitive adhesive composition that does not substantially contain a silicone material. The phrase “substantially free of silicone material” means that the Si—Kα ray intensity of fluorescent X-rays on the surface of the pressure-sensitive adhesive layer is 2.5 kcps or less. The pressure-sensitive adhesive composition can be used without particular limitation as long as it has adhesiveness, for example, acrylic pressure-sensitive adhesive composition, urethane-based pressure-sensitive adhesive composition, synthetic rubber-based pressure-sensitive adhesive composition, natural rubber-based An adhesive composition or the like can also be used, and among them, an acrylic adhesive composition can be preferably used.

<(Meth) acrylic polymer (A)>
The acrylic pressure-sensitive adhesive composition contains a (meth) acrylic polymer (A). The (meth) acrylic polymer refers to an acrylic polymer and / or a methacrylic polymer.

<C2-C14 alkyl group-containing (meth) acrylic monomer>
The (meth) acrylic polymer (A) is not particularly limited as long as it is an adhesive (meth) acrylic polymer. However, the main component of the monomer component is an alkyl group-containing (meth) having 2 to 14 carbon atoms. It is preferable to use an acrylic monomer. As the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms, one or more kinds can be used as a main component. The main component means that the blending ratio is the highest.

Specific examples of the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms include, for example, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl ( (Meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) ) Acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate and the like.

Among them, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) ) Acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. It is mentioned as a suitable thing. By using the (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend to be low, and the pressure-sensitive adhesive layer is excellent in removability.

The (meth) acrylic polymer (A) contains the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms based on the total amount of monomer components constituting the (meth) acrylic polymer (A). 50 to 99% by weight, more preferably 60 to 98% by weight, still more preferably 70 to 97% by weight, and most preferably 80 to 96% by weight. By being in this range, the pressure-sensitive adhesive composition has an appropriate wettability and is excellent in cohesive force of the pressure-sensitive adhesive layer, which is preferable.

<Hydroxyl group-containing (meth) acrylic monomer>
The (meth) acrylic polymer (A) preferably contains a hydroxyl group-containing (meth) acrylic monomer as a monomer component. By including the hydroxyl group-containing (meth) acrylic monomer, the hydroxyl group can easily control the cross-linking, and as a result, the improvement of wettability by flow and the balance of the cohesive force and shear force of the pressure-sensitive adhesive layer. It becomes easy to control. Further, when an antistatic agent is added to the pressure-sensitive adhesive layer, the hydroxyl group has a moderate interaction with an ionic compound as an antistatic agent, unlike a carboxyl group or a sulfonate group that can generally act as a crosslinking site. Therefore, it can be suitably used also in terms of antistatic properties.

Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate. , 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide and the like. The hydroxyl group-containing (meth) acrylic monomers may be used alone or in combination of two or more.

When the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms and the hydroxyl group-containing (meth) acrylic monomer are used in the (meth) acrylic polymer (A), the hydroxyl group-containing ( The (meth) acrylic monomer is preferably 2 to 20 parts by weight, more preferably 3 to 15 parts by weight with respect to 100 parts by weight of the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms. More preferably, it is 4 to 12 parts by weight. Within this range, it is easy to control the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force and shearing force of the pressure-sensitive adhesive layer, which is preferable.

<Carboxyl group-containing (meth) acrylic monomer>
The (meth) acrylic polymer (A) preferably contains a carboxyl group-containing (meth) acrylic monomer as a monomer component. By including the carboxyl group-containing (meth) acrylic monomer, the carboxyl group can improve the shearing force, and further prevent the adhesive force from increasing over time. It becomes an excellent pressure-sensitive adhesive layer. In particular, by improving the shearing force of the pressure-sensitive adhesive layer, it is possible to suppress curling based on the adherend by bonding the pressure-sensitive adhesive layer to the adherend, and between the pressure-sensitive adhesive layer and the adherend. It is possible to suppress the occurrence of slippage and deviation at the (interface).

Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, carboxylethyl (meth) acrylate, carboxylpentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2 -(Meth) acryloyloxypropyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl maleic acid, carboxy Examples thereof include polycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid. The carboxyl group-containing (meth) acrylic monomer may be used alone or in combination of two or more.

When the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms and the carboxyl group-containing (meth) acrylic monomer are used in the (meth) acrylic polymer (A), the carboxyl group-containing ( The (meth) acrylic monomer is preferably 0.01 to 1 part by weight, more preferably 0.001 part by weight with respect to 100 parts by weight of the (meth) acrylic monomer having an alkyl group having 2 to 14 carbon atoms. The amount is from 01 to 0.8 parts by weight, more preferably from 0.01 to 0.5 parts by weight, most preferably from 0.02 to 0.2 parts by weight. Within this range, the pressure-sensitive adhesive layer can be prevented from increasing in adhesive force over time, excellent in removability, adhesive force-preventing property, and workability, and the pressure-sensitive adhesive layer is agglomerated. Since it is excellent in shear force with force, it is preferable.

<Other polymerizable monomers>
In the (meth) acrylic polymer (A), other polymerizable monomers can be used as a monomer component without particular limitation as long as they do not impair the characteristics of the present invention. The other polymerizable monomer has a glass transition temperature in particular such that the Tg of the (meth) acrylic polymer (A) is −50 ° C. or lower and −100 ° C. or higher because the adhesive performance is easily balanced. And can be used to adjust the peelability.

Examples of the other polymerizable monomer include, for example, a cohesive force / heat resistance improving component such as a cyano group-containing monomer, a vinyl ester monomer, an aromatic vinyl monomer, an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, Components having a functional group that functions as an adhesive (adhesive) force-improving and crosslinking base point, such as an epoxy group-containing monomer, N-acryloylmorpholine, and vinyl ether monomer, can be appropriately used. These polymerizable monomers may be used alone or in combination of two or more.

Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, and vinyl laurate.

Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrene.

Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, and N, N-diethyl. Examples include methacrylamide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, diacetone acrylamide, and the like.

Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

The other polymerizable monomer is preferably 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight, based on the total amount of monomer components constituting the (meth) acrylic polymer (A). More preferably. By using the other polymerizable monomer within this range, for example, when using an ionic compound of an antistatic agent, appropriately adjust a good interaction with this compound and a good removability. Can do.

The (meth) acrylic polymer (A) has a weight average molecular weight (Mw) of 100,000 to 5,000,000, preferably 200,000 to 4,000,000, more preferably 300,000 to 3,000,000. When the weight average molecular weight is smaller than 100,000, the adhesive force tends to be generated due to a decrease in the cohesive force of the pressure-sensitive adhesive composition. On the other hand, when the weight average molecular weight (Mw) exceeds 5,000,000, the fluidity of the polymer is lowered, and the wettability to the adherend (for example, a polarizing plate as an optical member) becomes insufficient, and the adherend adheres to the adherend. There is a tendency to cause blisters occurring between the agent layer and the agent layer. In addition, a weight average molecular weight (Mw) says what was obtained by measuring by GPC (gel permeation chromatography).

The glass transition temperature (Tg) of the (meth) acrylic polymer (A) is preferably −50 ° C. or lower, more preferably −55 ° C. or lower, and further preferably −60 ° C. or lower. The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably −100 ° C. or higher. When the glass transition temperature is higher than −50 ° C., the polymer does not flow easily. For example, the adherend (for example, a polarizing plate which is an optical member) is insufficiently wetted, and the adherend and the adhesive layer There is a tendency to cause blisters that occur in between. In particular, when the glass transition temperature is −61 ° C. or lower, an adhesive composition excellent in wettability to the adherend and light peelability can be easily obtained. In addition, the glass transition temperature of the said (meth) acrylic-type polymer (A) can be adjusted in the said range by changing suitably the monomer component and composition ratio to be used.

The polymerization method of the (meth) acrylic polymer (A) is not particularly limited and can be polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. From the viewpoint of characteristics such as low contamination to the adherend, solution polymerization is a more preferable embodiment. Further, the polymer obtained may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, and the like.

It is preferable that the pressure-sensitive adhesive composition contains a crosslinking agent. As the crosslinking agent, an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative, a metal chelate compound, or the like may be used. In particular, the use of an isocyanate compound is a preferred embodiment. Moreover, these compounds may be used independently and may be used in mixture of 2 or more types.

<Aliphatic polyisocyanate crosslinking agent (B)>
Among the isocyanate compounds, the pressure-sensitive adhesive composition preferably contains an aliphatic polyisocyanate-based crosslinking agent (B). For example, when the said adhesive composition contains the said (meth) acrylic-type polymer (A), the structural unit of the said (meth) acrylic-type polymer (A), a structural ratio, an aliphatic polyisocyanate type crosslinking agent (B The pressure-sensitive adhesive layer having more excellent heat resistance can be obtained by appropriately adjusting the selection and addition ratio and the like.

Examples of the aliphatic polyisocyanate crosslinking agent (B) include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, Aliphatic isocyanates such as isophorone diisocyanate (IPDI), modified polyisocyanate modified from the above isocyanate compounds with allophanate bonds, biuret bonds, isocyanurate bonds, uretdione bonds, urea bonds, carbodiimide bonds, uretonimine bonds, oxadiazine trione bonds, etc. Is mentioned. For example, as commercial products, the brand names Takenate 300S, Takenate 500, Takenate D165N, Takenate D178N (above, Takeda Pharmaceutical Company Limited), Sumijoule T80, Sumijoule L, Death Module N3400 (above, Sumika Bayer Urethane Co., Ltd.) Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (above, manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. The aliphatic polyisocyanate-based crosslinking agent (B) may be used alone or in combination of two or more, and a bifunctional isocyanate compound and a trifunctional or higher isocyanate compound may be used in combination. Is also possible. By using a cross-linking agent in combination, it becomes possible to achieve both tackiness and resilience resistance (adhesiveness to a curved surface), and a surface protective film with better adhesion reliability can be obtained.

The content of the aliphatic polyisocyanate crosslinking agent (B) is, for example, preferably 1 to 30 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer (A). It is more preferably 20 parts by weight, further preferably 2 to 10 parts by weight, and most preferably 3 to 6 parts by weight. When the content is less than 1 part by mass, the crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the resulting pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained, and the adhesive residue There is a tendency to cause. On the other hand, when the content exceeds 30 parts by weight, the cohesive force of the polymer is large, the fluidity is lowered, and the adherend (for example, glass, polarizing plate, wave plate, retardation plate, optical material used for liquid crystal displays, etc.) Compensation film, reflection sheet, brightness enhancement film, and transparent conductive film and other optical members) are not sufficiently wetted, and tend to cause blisters occurring between the adherend and the adhesive layer. is there. Furthermore, when the amount of the crosslinking agent is large, the peeling charging property tends to be lowered.

<Catalyst (C)>
The pressure-sensitive adhesive composition can further contain a catalyst (C) in order to make the crosslinking reaction proceed more effectively. Examples of the catalyst (C) include tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonate) iron, tris (hexane-2,4-dionato) iron, tris (heptane-2,4). -Dionato) iron, tris (heptane-3,5-dionato) iron, tris (5-methylhexane-2,4-dionato) iron, tris (octane-2,4-dionato) iron, tris (6-methylheptane) -2,4-dionato) iron, tris (2,6-dimethylheptane-3,5-dionato) iron, tris (nonane-2,4-dionato) iron, tris (nonane-4,6-dionato) iron, Tris (2,2,6,6-tetramethylheptane-3,5-dionato) iron, tris (tridecan-6,8-dionato) iron, tris (1-phenylbutane-1,3 Diato) iron, tris (hexafluoroacetylacetonato) iron, tris (ethyl acetoacetate) iron, tris (acetoacetate-n-propyl) iron, tris (isopropyl acetoacetate) iron, tris (acetoacetate-n-butyl) Iron, tris (acetoacetate-sec-butyl) iron, tris (acetoacetate-tert-butyl) iron, tris (methyl propionylacetate) iron, tris (ethyl propionylacetate) iron, tris (propionylacetate-n-propyl) iron , Tris (propionyl acetate-isopropyl) iron, tris (propionyl acetate-n-butyl) iron, tris (propionyl acetate-sec-butyl) iron, tris (propionyl acetate-tert-butyl) iron, tris (benzyl acetoacetate) iron, Tris (dimethyl malonate) iron, tris (diethyl malonate) iron, trimethoxy iron, Iron-based catalysts such as triethoxy iron, triisopropoxy iron, and ferric chloride can be used. One type of catalyst (C) may be used, or two or more types may be used in combination.

Further, as the iron-based catalyst, an iron chelate compound can be suitably used, and for example, it can be expressed as a general formula Fe (X) (Y) (Z). The iron chelate compound is a combination of (X) (Y) (Z), Fe (X) ₃ , Fe (X) ₂ (Y), Fe (X) (Y) ₂ , Fe (X) (Y) (Z ). In the iron chelate compound Fe (X) (Y) (Z), (X) (Y) (Z) is a ligand for Fe, respectively. For example, when X, Y or Z is a β-diketone, β -As diketones, acetylacetone, hexane-2,4-dione, heptane-2,4-dione, heptane-3,5-dione, 5-methyl-hexane-2,4-dione, octane-2,4-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane-3,5-dione, nonane-2,4-dione, nonane-4,6-dione, 2,2,6,6-tetramethyl Examples include heptane-3,5-dione, tridecane-6,8-dione, 1-phenyl-butane-1,3-dione, hexafluoroacetylacetone, ascorbic acid and the like.

When X, Y or Z is β-ketoester, β-ketoester is methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, isopropyl acetoacetate, acetoacetate-n-butyl, acetoacetate-sec-butyl. , Acetoacetate-tert-butyl, methyl propionyl acetate, ethyl propionyl acetate, propionyl acetate-n-propyl, isopropyl propionyl acetate, propionyl acetate-n-butyl, propionyl acetate-sec-butyl, propionyl acetate-tert-butyl, acetoacetate Examples include benzyl, dimethyl malonate, diethyl malonate and the like.

Further, an iron-based catalyst other than the iron chelate compound can be used. For example, a compound of iron and an alkoxy group, a halogen atom, or an acyloxy group can be used. In the case of a compound of iron and an alkoxy group, the alkoxy group includes methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, pentyloxy group, hexyloxy Group, heptyloxy group, octyloxy group, 2-ethylhexyl group, phenoxy group, cyclohexyloxy group, benzyloxy group, 1-benzylnaphthyloxy group and the like.

In the case of the compound of iron and a halogen atom, examples of the halogen atom include fluorine, chlorine, bromine and iodine.

In the case of the compound of iron and acyloxy group, 2-ethylhexylic acid, octylic acid, naphthenic acid, resin acid (abietic acid, neoabietic acid, d-pimalic acid, iso-d-pimalic acid, podocarpic acid) , Gluconic acid, fumaric acid, citric acid, aspartic acid, α-ketoglutamic acid, malic acid, succinic acid, aliphatic organic acids mainly composed of amino acids such as glycine and histidine, benzoic acid, cinnamic acid, p -Aromatic fatty acids mainly composed of oxycinnamic acid and the like.

Among the iron-based catalysts, an iron chelate compound having a β-diketone as a ligand is preferable from the viewpoint of reactivity and curability, and tris (acetylacetonate) iron is particularly preferable.

The content (usage amount) of the catalyst (C) is preferably 0.002 to 0.5 parts by mass, for example, 0.005 to 0.005 parts per 100 parts by mass of the (meth) acrylic polymer (A). 3 parts by mass is more preferable, and 0.01 to 0.1 part by mass is even more preferable. Within this range, when the pressure-sensitive adhesive layer is formed, the speed of the cross-linking reaction is high, and the pot life of the pressure-sensitive adhesive composition is increased, which is a preferred embodiment.

Furthermore, the pressure-sensitive adhesive composition may contain a compound that causes keto-enol tautomerism as a crosslinking retarder. For example, in the pressure-sensitive adhesive composition containing the aliphatic polyisocyanate-based crosslinking agent (B) or the pressure-sensitive adhesive composition that can be used by blending the aliphatic polyisocyanate-based crosslinking agent (B), the keto-enol tautomerism is exhibited. An embodiment including the resulting compound can be preferably employed. Thereby, the effect which suppresses the excessive viscosity raise and gelatinization of an adhesive composition after mix | blending an aliphatic polyisocyanate type crosslinking agent (B), and extends the pot life of an adhesive composition can be implement | achieved. This technique can be preferably applied when, for example, the pressure-sensitive adhesive composition is in an organic solvent solution or a solvent-free form.

As the compound that produces the keto-enol tautomerism, various β-dicarbonyl compounds can be used. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane- Β-diketones such as 3,5-dione; acetoacetates such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, propionyl acetate propionyl acetates such as tert-butyl; isobutyryl acetates such as ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, tert-butyl isobutyryl acetate; malonic acid esters such as methyl malonate and ethyl malonate; etc. And the like. Among these, acetylacetone and acetoacetic acid esters are preferable compounds. Compounds that produce keto-enol tautomerism may be used alone or in combinations of two or more.

The content of the compound causing keto-enol tautomerism can be, for example, 0.1 to 20 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer (A). 5 to 15 parts by weight (for example, 1 to 10 parts by weight) is appropriate. If the amount of the compound is too small, it may be difficult to achieve a sufficient use effect. On the other hand, if the compound is used more than necessary, it may remain in the pressure-sensitive adhesive layer and reduce the cohesive force.

Furthermore, the pressure-sensitive adhesive composition may contain other known additives, such as powders such as colorants and pigments, surfactants, plasticizers, antistatic agents, tackifiers, Low molecular weight polymer, surface lubricant, leveling agent, antioxidant, corrosion inhibitor, light stabilizer, ultraviolet absorber, polymerization inhibitor, silane coupling agent, inorganic or organic filler, metal powder, particulate, foil It can be added as appropriate depending on the intended use of the product.

<Preparation of optical surface protective film>
The optical surface protective film has a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition on one side of the polyester film. In this case, the pressure-sensitive adhesive composition is crosslinked. However, it is also possible to transfer a pressure-sensitive adhesive layer comprising a crosslinked pressure-sensitive adhesive composition to a substrate or the like.

The method for forming the pressure-sensitive adhesive layer on the polyester film is not particularly limited. For example, the solution of the pressure-sensitive adhesive composition is applied to the film, and the polymerization solvent is dried and removed to form the pressure-sensitive adhesive layer on the film. It is produced by forming. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. In addition, when the pressure-sensitive adhesive composition is applied on a polyester film to produce a pressure-sensitive adhesive layer, one or more solvents other than the polymerization solvent are newly added to the pressure-sensitive adhesive composition so that the pressure-sensitive adhesive composition can be uniformly applied on the film. You may add to.

In addition, as a method for forming the pressure-sensitive adhesive layer, a known method used for manufacturing the pressure-sensitive adhesive layer is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

The thickness of the pressure-sensitive adhesive layer is preferably 3 to 100 μm, more preferably about 5 to 50 μm. When the thickness of the pressure-sensitive adhesive layer is within this range, it is preferable because it is easy to obtain an appropriate balance between removability and adhesion (adhesion).

<Separator>
In the optical surface protective film of the present invention, a separator is bonded to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive layer surface. The separator includes a base material and a release layer.

<Base material>
Examples of the substrate include paper and plastic film, and a plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer Examples thereof include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the substrate is usually about 5 to 200 μm, preferably about 10 to 100 μm. Within this range, it is preferable because it is excellent in workability for bonding to the pressure-sensitive adhesive layer and workability for peeling from the pressure-sensitive adhesive layer.

The surface of the substrate can be subjected to various surface treatments such as corona discharge treatment or various surface treatments such as embossing as necessary. If necessary, fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, UV absorbers, antistatic agents, lubricants, plasticizers, colorants (pigments, dyes, etc.), etc. These various additives may be blended.

<Release layer>
The release layer is formed from a release agent composition that has adhesiveness to the substrate and has releasability with respect to the pressure-sensitive adhesive layer, and does not substantially contain a silicone material. The phrase “substantially free of silicone material” means that the surface of the release layer of the separator has a Si—Kα ray intensity (a) with fluorescent X-rays and a substrate having no release layer of the separator. The difference [(b)-(a)] in the Si-Kα ray intensity (b) with fluorescent X-rays on the surface (untreated surface) is 0.3 kcps or less.

The release agent composition preferably contains a long-chain alkyl material and / or an aliphatic carboxylic acid ester. These compounds can be effectively peeled even if incorporated in a small amount in the release agent composition, and the coating layer formed from the release layer composition has an appearance with no unevenness or whitening. This is preferable. These compounds may be used alone or in combination of two or more.

<Long-chain alkyl materials>
The long-chain alkyl material is a compound having a linear or branched alkyl group having 6 or more carbon atoms, preferably 8 or more carbon atoms, more preferably 12 or more carbon atoms. Examples of the alkyl group include octyl group, decyl group, lauryl group, octadecyl group, and behenyl group. Examples of the compound having an alkyl group include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary ammonium salts. . In view of heat resistance and contamination, a polymer compound is preferable. Further, from the viewpoint that moderate water repellency can be effectively obtained with a small content, a polymer compound having a long-chain alkyl group in the side chain is more preferable.

The polymer compound having a long-chain alkyl group in the side chain is a (meth) acrylic polymer obtained by polymerizing a monomer component containing an alkyl group-containing (meth) acrylic monomer having 6 or more carbon atoms, or a reactive property. Examples thereof include a polymer that can be obtained by reacting a polymer having a group with a compound having an alkyl group capable of reacting with the reactive group. Examples of the reactive group include a hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Examples of compounds having these reactive groups include polyvinyl alcohol, butyral resin, ethylene-vinyl alcohol resin, polyethyleneimine, polyethyleneamine, reactive group-containing polyester resin, and reactive group-containing poly (meth) acrylic resin. Can be mentioned. Among these, in view of releasability and ease of handling, (meth) acrylic polymers, polyvinyl alcohol, butyral resins, and ethylene vinyl alcohol resins are preferable.

<Alkyl group-containing (meth) acrylic polymer having 6 or more carbon atoms>
The (meth) acrylic polymer obtained by polymerizing a monomer component containing an alkyl group-containing (meth) acrylic monomer having 6 or more carbon atoms is based on the total amount of monomer components constituting the (meth) acrylic polymer. The alkyl group-containing (meth) acrylic monomer having 6 or more carbon atoms is preferably contained in an amount of 10 to 80% by weight, more preferably 20 to 70% by weight, still more preferably 30 to 70% by weight, most preferably Preferably, it is 30 to 60% by weight. By being in this range, the obtained release layer is excellent in light release property to the pressure-sensitive adhesive layer.

Examples of other polymerizable monomers other than the alkyl group-containing (meth) acrylic monomer having 6 or more carbon atoms include hydroxyl group-containing (meth) acrylic monomers, carboxyl group-containing (meth) acrylic monomers, and cyano. A group-containing monomer, vinyl ester monomer, aromatic vinyl monomer, amide group-containing monomer, imide group-containing monomer, amino group-containing monomer, epoxy group-containing monomer, N-acryloylmorpholine, vinyl ether monomer, and the like can be used as appropriate. These polymerizable monomers may be used alone or in combination of two or more.

Among them, it is preferable to use a carboxyl group-containing (meth) acrylic monomer and a cyano group-containing monomer from the viewpoint of excellent light peelability to the adhesive layer and excellent adhesion to the substrate. Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, carboxylethyl (meth) acrylate, carboxylpentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (Meth) acryloyloxypropyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl maleic acid, carboxypoly Examples include caprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid. Examples include acrylonitrile and methacrylonitrile. Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

<Polymer obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group>
Examples of the compound having an alkyl group capable of reacting with the reactive group include, for example, long-chain alkyl group-containing isocyanates such as octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, and behenyl isocyanate, octyl chloride, decyl chloride, Examples include long-chain alkyl group-containing acid chlorides such as lauryl chloride, octadecyl chloride, and behenyl chloride, long-chain alkyl group-containing amines, and long-chain alkyl group-containing alcohols. Among these, long chain alkyl group-containing isocyanates are preferable, and octadecyl isocyanate is particularly preferable in consideration of releasability and ease of handling.

The compound having an alkyl group capable of reacting with the reactive group is preferably reacted in an amount of 100 to 1000 parts by weight, more preferably 200 to 800 parts by weight, per 100 parts by weight of the polymer having the reactive group. 300 to 700 parts by weight are more preferable. When it exists in this range, since the light peelability with respect to an adhesive layer and the contamination to the adhesive layer of the surface protection film for optics can be suppressed, it is preferable.

<Aliphatic carboxylic acid ester>
The aliphatic carboxylic acid ester is obtained by reacting an aliphatic carboxylic acid with an alcohol. The aliphatic carboxylic acid component is preferably a mono- or dicarboxylic acid having 6 to 36 carbon atoms, and more preferably an aliphatic saturated monocarboxylic acid having 6 to 36 carbon atoms. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, valeric acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, mellic acid, and tetrariacontanoic acid. , Montanic acid, glutaric acid, adipic acid, azelaic acid and the like.

On the other hand, examples of the alcohol include saturated or unsaturated monohydric alcohols and saturated or unsaturated polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Of these alcohols, monovalent or polyvalent saturated alcohols having 30 or less carbon atoms are preferable, and aliphatic saturated monohydric alcohols or polyhydric alcohols having 30 or less carbon atoms are more preferable. Here, the aliphatic alcohol also includes an alicyclic alcohol. Specific examples of these alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol. Etc. These aliphatic carboxylic acid esters may contain an aliphatic carboxylic acid and / or alcohol as impurities, and may be a mixture of a plurality of compounds.

Specific examples of the aliphatic carboxylic acid ester include beeswax (mixture based on myristyl palmitate), stearyl stearate, behenyl behenate, octyldodecyl behenate, glycerin monopalmitate, glycerin monostearate, Examples thereof include glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, and pentaerythritol tetrastearate.

The carboxylic acid ester is preferably contained in the release agent composition in an amount of 70 to 99% by weight, more preferably 80 to 99% by weight, and still more preferably 90 to 99% by weight. When it exists in this range, it is preferable from the point which is excellent in the light peelability with respect to an adhesive layer.

Furthermore, the release agent composition may contain other known additives such as antistatic agents, powders such as colorants, pigments, surfactants, plasticizers, and tackifiers. , Low molecular weight polymers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, UV absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particulates, etc. Can be added as appropriate according to the intended use.

<Preparation of separator>
The separator is formed on the base material using the release agent composition.

The method for forming the release layer on the substrate is not particularly limited. For example, the release agent composition solution is applied to the substrate, and the polymerization solvent is dried and removed to remove the release layer on the substrate. It is produced by forming. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the release layer. Further, when the release agent composition is applied onto the substrate to produce a release layer, the release agent composition contains at least one polymerization solvent other than the polymerization solvent so that it can be uniformly applied onto the substrate. A new solvent may be added.

Further, as a method for forming the release layer, a known method used for manufacturing the release layer is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

The thickness of the release layer is typically 1 to 200 nm, preferably 5 to 100 nm, more preferably 10 to 50 nm. When the thickness of the release layer is too small, it is difficult to peel the separator, and therefore, the work of attaching the optical surface protective film may be difficult. On the other hand, if it is too thick, it may affect the contamination of the pressure-sensitive adhesive layer of the optical surface protective film.

<Lamination of optical surface protective film and separator>
The optical surface protective film with a separator of the present invention is a form in which the pressure-sensitive adhesive layer of the optical surface protective film and the release layer of the separator are bonded together. A known manufacturing method is used for the bonding.

<Measurement of Si-Kα intensity by fluorescent X-ray>
In the optical surface protective film with a separator of the present invention, the surface of the pressure-sensitive adhesive layer is determined by the intensity of the Si—Kα ray in the fluorescent X-rays on the surface of the pressure-sensitive adhesive layer after peeling off the separator bonded to the surface protective film for optical use. The silicon atomic weight of can be measured. The Si—Kα ray intensity of fluorescent X-rays on the pressure-sensitive adhesive layer surface is 2.5 kcps or less, preferably 2.4 or less, more preferably 2.2 or less, and most preferably 2.0. It is as follows. In this range, when the optical surface protective film from which the separator has been peeled is attached to an adherend (for example, a glass plate) and then peeled off, the surface of the adherend is contaminated by the adhesive layer. (For example, an organosilicone compound such as polydimethylsiloxane contained in the release layer of the separator for improving the peelability is applied to the surface of the pressure-sensitive adhesive layer by sticking the separator and the optical surface protective film.) And the transferred organic silicone compound can be further prevented from being transferred to the adherend). As a result, peeling of other layers such as an interlayer filler (layer) provided on the adherend can be prevented.

<Measurement of difference in peel strength of adhesive tape>
The influence of surface contamination on the adherend can be measured by the difference in the peel strength of the adhesive tape. The difference in the peel strength of the pressure-sensitive adhesive tape is obtained by the formula (1): difference in peel strength of the pressure-sensitive adhesive tape (N / 50 mm) = F ₀ −F (N / 50 mm).
Here, F denotes an optical surface protective film from which the separator has been peeled off, and is bonded to a glass plate as an adherend, heated at 70 ° C. for 48 hours, and then left at room temperature for 1 hour. Nitto Denko Co., Ltd. single-sided adhesive tape product number “No. 31B” (width 19 mm) was bonded to the surface of the glass plate to which the optical surface protective film had been bonded using a 2 kg roller at 23 ° C., 50 The peel strength (N / 19 mm) of the pressure-sensitive adhesive tape when peeled at a peel angle of 180 ° and a tensile speed of 0.3 m / min for 20 minutes under the condition of% RH was converted into a measured value at a width of 50 mm. Peeling force (N / 50 mm).
In addition, F ₀ is not directly bonded to the glass plate with the optical surface protective film, but directly bonded to the surface of the glass plate using a 2 kg roller with the Nitto Denko Corporation single-sided adhesive tape product number “No. 31B”. The peeling force (N / 19 mm) of the pressure-sensitive adhesive tape when peeled at a peeling angle of 180 ° and a tensile speed of 0.3 m / min for 20 minutes under the conditions of 23 ° C. and 50% RH The peel force (N / 50 mm) converted to a measured value.

The difference in peel strength of the adhesive tape is an index of adhesion with other layers (for example, interlayer filler (layer)) provided on the optical member after peeling the optical surface protective film, The degree of contamination of the surface of the adherend can be evaluated.

The difference in peel strength between the adhesive tapes is preferably 4.0 N / 50 mm or less, more preferably 3.6 N / 50 mm or less, still more preferably 3.2 N / mm or less, and most preferably 2.8 or less. In this range, after the optical protective film is peeled off, the influence of contamination on the adherend surface by the adhesive layer is small, and other layers such as an interlayer filler (layer) provided on the adherend Can be prevented.

<Measurement of peel strength of separator on optical surface protective film>
The optical surface protective film with a separator of the present invention is bonded to an optical surface protective film and a separator, and is allowed to stand for 20 minutes under conditions of 23 ° C. and 50% RH, and then has a peeling angle of 180 ° and a peeling speed of 0.3 m / min. The peeling force with respect to the optical surface protective film of a separator can be calculated | required by peeling according to conditions. The peeling force of the separator with respect to the optical surface protective film is 0.5 N / 50 mm or less, preferably 0.4 N / 50 mm or less, more preferably 0.3 N / 50 mm or less, and still more preferably 0.2 N / 50 mm or less. 0.1 N / 50 mm or less is most preferable. Moreover, 0.03 N / 50 mm or more is preferable, 0.05 N / 50 mm or more is more preferable, and 0.08 N / 50 mm or more is further more preferable. When it is within this range, the separator is excellent in releasability from the pressure-sensitive adhesive layer and is excellent in workability during bonding.

<Measurement of peel strength of optical surface protective film for glass>
The optical surface protective film with a separator of the present invention is an optical surface protective film from which the separator has been peeled off and is bonded to the surface of a glass plate with a 2 kg roller, and then 20 minutes have passed under conditions of 23 ° C. and 50% RH. The peeling force with respect to the glass of the surface protection film for optics can be calculated | required by peeling on conditions with a peeling angle of 180 degrees and a tensile speed of 0.3 m / min. The peel strength of the optical surface protective film for glass is preferably 0.08 N / 25 mm or less, preferably 0.07 N / 25 mm or less, more preferably 0.06 N / 25 mm or less, and 0.05 N / 25 mm or less. Is more preferable, and 0.04 N / 25 mm or less is most preferable. Moreover, 0.01 N / 25 mm or more is preferable, 0.02 N / 25 mm or more is more preferable, and 0.03 N / 25 mm or more is further more preferable. When in this range, the pressure-sensitive adhesive layer is excellent in releasability from an adherend such as glass.

<Measurement of element ratio of silicon atom by X-ray photoelectron spectroscopy (ESCA)>
In the optical surface protective film with a separator of the present invention, the surface of the pressure-sensitive adhesive layer after the separation of the separator bonded to the optical surface protective film is measured by X-ray photoelectron spectroscopy, whereby The element ratio (atomic%) about the silicon atom (Si) on the surface can be calculated. The element ratio (atomic%) with respect to the silicon atom (Si) on the outermost surface of the pressure-sensitive adhesive layer is preferably 0.5 or less, more preferably 0.3 or less, and most preferably 0.2 or less. is there. In this range, when the optical surface protective film from which the separator has been peeled is attached to an adherend (for example, a glass plate) and then peeled off, the surface of the adherend is contaminated by the adhesive layer. (For example, an organosilicone compound such as polydimethylsiloxane contained in the release layer of the separator for improving the peelability is applied to the surface of the pressure-sensitive adhesive layer by sticking the separator and the optical surface protective film.) And the transferred organic silicone compound can be further prevented from being transferred to the adherend). As a result, peeling of other layers such as an interlayer filler (layer) provided on the adherend can be prevented.

Examples of other layers provided on the adherend after peeling off the optical surface protective film of the present invention include an interlayer filler (layer). The interlayer filler (layer) is used for the purpose of, for example, filling between a cover glass and a liquid crystal panel to improve visibility. Specifically, the SVR7000 series, SVR1120, SVR1150, SVR1320, SVR1241H (manufactured by Dexerials), WORLD ROCK 700 series, WORLD ROCK801, A-350 series, WORLD ROCK HRJ-40, HRJ-203, HRJ-300, and HRJ-302 (manufactured by Kyoritsu Chemical Industry Co., Ltd.).

Hereinafter, examples and the like specifically showing the configuration and effects of the present invention will be described, but the present invention is not limited thereto. In addition, the evaluation item in an Example etc. measured as follows.

<Example 1>
<Preparation of (meth) acrylic polymer (A1)>
To a four-flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by weight of 2-ethylhexyl acrylate (2EHA, manufactured by Toagosei Co., Ltd., 2-ethylhexyl acrylate), 2-hydroxyethyl acrylate (HEA, Toa Gosei Co., Ltd., Acrix HEA) 4 parts by weight, 2,2′-azobisisobutyronitrile (Wako Pure Chemical Industries, AIBN) 0.2 part by weight as a polymerization initiator, ethyl acetate (Showa Denko, ethyl acetate) ) 205 parts by weight, nitrogen gas was introduced with gentle stirring, and the polymerization temperature was kept at around 63 ° C. for about 4 hours to carry out the polymerization reaction, and the (meth) acrylic polymer (A1) solution (about 35% by weight) was prepared. The (meth) acrylic polymer (A1) had a weight average molecular weight of 650,000 and Tg of −68.3 ° C.

<Preparation of pressure-sensitive adhesive composition>
The (meth) acrylic polymer (A1) solution (about 35% by weight) was diluted to 29% by weight with ethyl acetate, and hexamethylene was added to 100 parts by weight (solid content) of the (meth) acrylic polymer in this solution. 4 parts by weight of isocyanurate of diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX), 0.015 part by weight of dioctyltin laurate (manufactured by Tokyo Fine Chemical Co., Ltd., Encapsulator OL-1), keto-enol tautomerism 0.69 parts by weight of acetylacetone was added as a compound that yields a pressure-sensitive adhesive composition, and the mixture was stirred at about 25 ° C. for about 1 minute to prepare an adhesive composition (1).

<Preparation of separator A>
100 parts by weight of a resin obtained by drying butyral resin (manufactured by Sekisui Chemical Co., Ltd., ESREC KW-10) is dissolved in 900 parts by weight of xylene (manufactured by Taiyo Chemical Co., Ltd., xylol), followed by octadecyl isocyanate (manufactured by Ohara Paradium Chemical Co., Ltd.). , R-NCO) was added at 480 parts by weight. Further, this solution was diluted with toluene (manufactured by Idemitsu Petrochemical Co., Ltd.) so that the solid content became 0.3% by weight to obtain a release agent composition. This release agent composition was applied to a PET film having a thickness of 38 μm (manufactured by Mitsubishi Plastics, Diafoil T100C38) and dried at 130 ° C. for 1 minute to prepare separator A. The thickness of the release layer after drying was 20 nm.

<Preparation of optical surface protective film with separator>
The pressure-sensitive adhesive composition (1) is applied to one side of a PET substrate (Mitsubishi Resin, Diafoil T100C38, thickness 38 μm) and heated at 130 ° C. for 60 seconds to form a pressure-sensitive adhesive layer having a thickness of 10 μm. Thus, an optical surface protective film was produced. Subsequently, the release layer of the separator A was bonded to the surface of the pressure-sensitive adhesive layer with a hand roller to prepare an optical surface protective film with a separator. In addition, at the time of sticking (use) to a to-be-adhered body, the said separator was removed and used.

<Preparation of separator B>
In a reaction vessel equipped with a cooler, 100 parts by weight of acrylonitrile (manufactured by Showa Denko KK, acrylonitrile), 62.5 parts by weight of stearyl methacrylate (manufactured by Mitsubishi Gas Chemical Co., Ltd., SMA), methacrylic acid (Mitsubishi Rayon Co., Ltd.) 18 parts by weight of methacrylic acid), 1.8 parts by weight of 1-dodecanethiol (manufactured by Wako Pure Chemical Industries, Ltd., 1-dodecanethiol), and 0.1% of benzoyl peroxide (manufactured by NOF Corporation, Nyper BW). 55 parts by weight, diluted with toluene (made by Idemitsu Petrochemical Co., Ltd.) to 24% by weight, and reacted at 70 ° C. for 7 hours under a nitrogen stream. The obtained liquid was diluted to 0.3% by weight with toluene to obtain a release agent composition, and then separator B was produced in the same manner as separator A.

<Separator C>
Toyobo's Toyobo Ester Film TN101 (thickness 38 μm) was used. The release layer constituting the separator C is formed by a release agent composition containing pentaerythritol fatty acid ester.

<Preparation of separator D>
In a reaction vessel equipped with a cooler, 200 parts by weight of xylene (manufactured by Taiyo Chemical Co., Ltd., xylol) and 600 parts by weight of octadecyl isocyanate (manufactured by Ohara Palladium Chemical Co., Ltd., R-NCO) are added and heated with stirring to reflux the xylene. From the beginning, 100 parts by weight of polyvinyl alcohol (manufactured by Kuraray, Kuraray Poval 205) was added in small portions at intervals of 10 minutes over 2 hours. After the addition of polyvinyl alcohol, the reaction was further refluxed for 2 hours to complete the reaction. When the reaction mixture was cooled to about 80 ° C. and added to methanol, the reaction product was precipitated as a white precipitate. This precipitate was filtered off, added with 140 parts by weight of xylene, and heated to dissolve completely. After repeating the operation of adding methanol again to precipitate several times, the precipitate was washed with methanol, dried and pulverized, and the powder obtained was diluted with water to 0.3% by weight. Separator D was prepared in the same manner as separator A using the obtained solution.

<Separator E>
A film binder 50E-0010NSD (thickness 50 μm) manufactured by Fujimori Kogyo was used. The release layer constituting the separator E is formed of a release agent composition containing pentaerythritol fatty acid ester.

<Separator F>
100 parts by weight of a silicone release agent (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847H), 3.3 parts by weight of a silicone curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T), toluene (manufactured by Idemitsu Petrochemical), Hexane (manufactured by Maruzen Petrochemical Co., Ltd., normal hexane) and methyl ethyl ketone (manufactured by Idemitsu Kosan Co., Ltd., MEK) were diluted to 0.3% by weight with a solvent having a weight ratio of 1: 2: 1 to obtain a release agent composition. A separator F was produced in the same manner as the separator A using the obtained release agent composition.

<Examples 2 to 8, Comparative Examples 1 to 3, Blank 1>
As shown in Tables 1 and 2, in the same manner as in Example 1 except that the monomer components constituting the (meth) acrylic polymer and the treatment of the separator were changed, Examples 2 to 8, and Optical surface protective films with separators of Comparative Examples 1 to 3 were prepared. As blank 1, an optical surface protective film that does not use a separator was produced. As the iron catalyst, tris (acetylacetonate) iron (manufactured by Nippon Kagaku Sangyo Co., Ltd., trade name “Nursem Ferric Iron”) was used.

<Measurement / Evaluation>
Hereinafter, specific blending amounts and measurement / evaluation methods are described, and the results are shown in Tables 1 and 2.

<Measurement of weight average molecular weight (Mw) of (meth) acrylic polymer (A)>
The weight average molecular weight of the produced polymer was measured by GPC (gel permeation chromatography). The conditions are shown below.

Equipment: Tosoh Corporation, HLC-8220GPC
Sample column: TSK guard column Super HZ-H manufactured by Tosoh Corporation
(1) + TSKgel Super HZM-H (2)
Reference column: TSKgel Super H-RC (1 piece), manufactured by Tosoh Corporation
Flow rate: 0.6ml / min
Injection volume: 10 μl
Column temperature: 40 ° C
Eluent: THF
Injection sample concentration: 0.2% by weight
Detector: differential refractometer The weight average molecular weight was calculated in terms of polystyrene.

<Measurement of glass transition temperature (Tg) of (meth) acrylic polymer (A)>
The glass transition temperature (Tg) (° C.) was determined by the following formula using the following literature values as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.

Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
(Wherein Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the weight fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer. Represents.)
2-Ethylhexyl acrylate (2EHA): -70 ° C
Hydroxyethyl acrylate (HEA): -15 ° C
4-hydroxybutyl acrylate (HBA): -32 ° C
Acrylic acid (AA): 106 ° C
In addition, as a reference value, “Synthesis / design of acrylic resin and development of new application” (published by Central Management Development Center Publishing Department) was referred.

<Measurement of Si-Kα line intensity>
From the obtained optical surface protective film with a separator, the amount of silicon atoms on the surface of the pressure-sensitive adhesive layer was measured under the following conditions by the Si—Kα ray intensity of fluorescent X-rays on the surface of the pressure-sensitive adhesive layer after peeling the separator. .
Equipment: XRF ZSX100e manufactured by Rigaku
X-ray source: Vertical Rh tube analysis area: 30mmφ
Analytical element: Si
Spectroscopic crystal: RX4
Output: 50kv, 70mA
The sample (area = 30 mmφ) was irradiated with excitation X-rays (radiation source = vertical Rh tube, output = 50 kv, 70 mA), and the intensity of X-ray fluorescence of Si dispersed with a spectral crystal (= RX4) was measured. .

Further, the Si—Kα ray intensity with fluorescent X-rays was also measured on the pressure-sensitive adhesive layer surface of the optical surface protective film (blank 1) without using a separator under the above conditions. As a result, the amount of silicon atoms is not limited to the use of a silicone material for the pressure-sensitive adhesive layer or the release layer, but also for silicon atoms of polyester films and substrates (for example, silica (SiO ₂ ) of filler in PET film). In order to detect, the Si-Kα ray intensity did not become 0 kcps, and the pressure-sensitive adhesive layer of the optical surface protective film (blank 1) without using a separator showed 1.9 kcps.

The Si—Kα line intensity on the pressure-sensitive adhesive layer surface after peeling off the separator is preferably 2.5 kcps or less. Within this range, the optical surface protective film from which the separator has been peeled off is less affected by the contamination of the glass surface by the pressure-sensitive adhesive layer after peeling from the glass plate (for example, the release layer of the separator is peelable). An organic silicone compound such as polydimethylsiloxane contained for improvement is transferred to the surface of the pressure-sensitive adhesive layer by sticking a separator and an optical surface protective film, and the transferred organic silicone compound is further applied. For example, it is possible to prevent peeling of another layer such as an interlayer filler (layer) from the adherend.

<Measurement of difference in peel strength of adhesive tape>
The separator was peeled off from the obtained optical surface protective film with a separator and bonded to a glass plate (manufactured by Matsunami Glass, blue plate edge polished product OF1), and heated in an oven at 70 ° C. for 48 hours. After removing from the oven and leaving at room temperature for 1 hour, the optical surface protective film was peeled off, and an acrylic adhesive tape (Nitto Denko Corporation, No. 31B, width 19 mm) was applied to the surface on which the optical surface protective film was pasted. They were stuck together using a roller and left in an environment of 23 ° C. and 50% relative humidity for about 20 minutes. The film was peeled off at an angle of 180 ° at a speed of 0.3 m / min, the peeling force was measured, converted into a measured value at a width of 50 mm, and this was taken as the value of F in the following formula (1).
In addition, No. was directly applied to the glass plate without attaching an optical surface protective film. 31B was bonded and the peel force was measured in the same manner, and converted to a measured value at a width of 50 mm to obtain a value of F _{0 in} the following formula (1). In this case, no. The peel strength of 31B was 18.7 N / 50 mm.
And the difference of the peeling force of these adhesive tapes was computed by following formula (1).
Formula (1): Difference in peel strength of adhesive tape (N / 50 mm) = F ₀ −F (N / 50 mm)

The difference in the peel strength of the adhesive tape is preferably 4.0 N / 50 mm or less. The smaller this value is, the less the influence of the contamination of the glass surface by the pressure-sensitive adhesive layer after peeling off the optical protective film. For example, other layers such as an interlayer filler (layer) provided on the glass surface Can be prevented.

<Measurement of peel strength of separator on optical surface protective film>
The obtained optical surface protective film with a separator was cut into a width of 50 mm, and the surface (polyester film) opposite to the surface on which the adhesive layer was adhered was fixed to the SUS plate (SUS304BA). After leaving for about 20 minutes in an environment of 23 ° C. and 50% relative humidity, the separator is peeled off at an angle of 180 ° at a speed of 0.3 m / min, and the peeling force of the separator against the optical surface protective film (N / 50 mm) Was measured.

The peel strength of the separator with respect to the optical surface protective film is preferably 0.5 N / 50 mm or less. When it is within this range, the separator is excellent in releasability from the pressure-sensitive adhesive layer and is excellent in workability at the time of bonding.

<Evaluation of separator peelability>
The separator peelability was evaluated as good (◯) when the peel strength of the separator with respect to the optical surface protective film was 0.5 N / 50 mm or less, and poor (X) when it was larger than 0.5 N / 50 mm.

<Measurement of peel strength of optical surface protective film for glass>
The obtained optical surface protective film with a separator was cut to a width of 25 mm, the separator was peeled off, and the glass plate (made by Matsunami Glass, blue plate edge polished product, OF1) was bonded using a 2 kg roller. It was left in an environment with a humidity of 50% for about 20 minutes. The optical surface protective film was peeled off at an angle of 180 ° at a speed of 0.3 m / min, and the peel force (N / 25 mm) of the optical surface protective film to the glass was measured.

The peel strength of the optical surface protective film for glass is preferably 0.08 N / 25 mm or less. When in this range, an optical protective film having a pressure-sensitive adhesive layer excellent in peelability from an adherend such as glass is obtained.

<Measurement of element ratio of silicon atom by X-ray photoelectron spectroscopy (ESCA)>
The element ratio of silicon atoms (Si) on the outermost surface of the pressure-sensitive adhesive layer was measured by X-ray photoelectron spectroscopy on the surface of the pressure-sensitive adhesive layer after peeling the separator from the obtained optical surface protective film with a separator. It was calculated according to the conditions of
Equipment: PHI Quantera SXM manufactured by ULVAC PHI
X-ray source: Monochrome AlKα
XRay Setting: 100 μmφ [15 kV, 25 W]
Photoelectron extraction angle: 45 ° to the sample surface
The obtained optical surface protective film with a separator was appropriately cut out, measured by X-ray photoelectron spectroscopy, and the element ratio (atomic%) was calculated for silicon atoms.

The element ratio of the silicon atom is preferably 0.5 atomic% or less. Within this range, the optical surface protective film from which the separator has been peeled off is less affected by the contamination of the glass surface by the pressure-sensitive adhesive layer after peeling from the glass plate (for example, the release layer of the separator is peelable). An organic silicone compound such as polydimethylsiloxane contained for improvement is transferred to the surface of the pressure-sensitive adhesive layer by sticking a separator and an optical surface protective film, and the transferred organic silicone compound is further applied. For example, it is possible to prevent peeling of another layer such as an interlayer filler (layer) from the adherend.

<Measurement of difference in Si-Kα ray intensity by fluorescent X-ray between the surface of the release layer of the separator and the surface of the base material of the separator>
According to the above-mentioned measurement conditions for the Si-Kα ray intensity, the Si-Kα ray intensity (a) in the fluorescent X-ray on the surface of the release layer of the separator and the surface of the substrate not having the release layer of the separator (not yet) The Si—Kα intensity (b) of the treated surface) with fluorescent X-rays was measured, and the difference [(b) − (a)] was determined. As a result, the Si—Kα line intensity (a) of the separator C was 3.78 kcps, and the Si—Kα line intensity (b) of the separator C was 3.98 kcps, so the difference [(b) − (A)] was 0.20 kcps. Further, since the Si-Kα line intensity (a) of the separator E was 6.52 kcps and the Si-Kα line intensity (b) of the separator E was 6.73 kcps, the difference [(b) − ( a)] was 0.21 kcps. Further, since the Si-Kα line intensity (a) of the separator F was 75.5 kcps and the Si-Kα line intensity (b) of the separator F was 7.36 kcps, the difference [(b) − ( a)] was 68.14 kcps.

 

 

From the results of Table 2 above, in all Examples, the Si—Kα line intensity is 2.5 kcps or less, so that the contamination resistance is excellent, and the peeling force of the separator against the optical surface protective film is 0.5 N / Since it is 50 mm or less, it was confirmed that the workability at the time of bonding was excellent. On the other hand, in Comparative Examples 1 and 3, the Si—Kα line intensity is larger than 2.5 kcps, and in Comparative Example 2, the peeling force of the separator against the adhesive layer is larger than 0.5 N / 50 mm. It was confirmed that No. 3 was inferior in these performances compared with the Example.

In addition, from the results of Table 2 above, in all examples, the difference in the peel strength of the adhesive tape is 4.0 N / 50 mm or less, and therefore the glass of the adhesive layer when the optical protective film is peeled off. Since the influence of the surface contamination is small, for example, peeling of other layers such as an interlayer filler (layer) can be prevented, and the peel strength of the surface protective film to the glass is 0.08 N / 25 mm or less. It was confirmed that the film was excellent in peelability. Moreover, the separator peelability was good. In addition, since the element ratio of the silicon atom (Si) on the outermost surface of the pressure-sensitive adhesive layer is 0.5 atomic% or less, it was confirmed that the contamination resistance was excellent. On the other hand, in Comparative Examples 1 and 3, the difference in the peel strength of the adhesive tape is greater than 4.0 N / 50 mm, and the element ratio of silicon atoms on the outermost surface of the adhesive layer is 2.0 atomic% or more. Yes, in Comparative Example 2, the peel strength of the optical surface protective film to the glass is greater than 0.08 N / 25 mm, and the separator peelability is poor. Comparative Examples 1 to 3 are compared with the Examples, It was confirmed that these performances were inferior.

1: Separator 2: Optical surface protective film 3: Optical surface protective film with separator 11: Base material 12: Release layer 21: Adhesive layer 22: Polyester film

Claims (6)

1. An optical surface protective film with a separator having a polyester film on one side of the pressure-sensitive adhesive layer and having a separator on the opposite side of the polyester film of the pressure-sensitive adhesive layer,
   The Si—Kα ray intensity with fluorescent X-rays on the pressure-sensitive adhesive layer surface after peeling the separator is 2.5 kcps or less,
   An optical surface protective film with a separator, wherein a peeling force of the separator with respect to the optical surface protective film is 0.5 N / 50 mm or less at a tensile speed of 0.3 m / min.
2. The separator has a release layer and a substrate;
   The optical surface protective film with a separator according to claim 1, wherein the release layer is formed from a release agent composition containing a long-chain alkyl material and / or an aliphatic carboxylic acid ester.
3. The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer (A) and an aliphatic polyisocyanate-based crosslinking agent (B),
   The (meth) acrylic polymer (A) contains at least an alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms and a hydroxyl group-containing (meth) acrylic monomer as a monomer component, and glass The transition temperature is −50 ° C. or lower,
   The separator according to claim 1 or 2, comprising 2 to 20 parts by weight of the hydroxyl group-containing (meth) acrylic monomer with respect to 100 parts by weight of the alkyl group-containing (meth) acrylic monomer having 2 to 14 carbon atoms. Surface protective film for optics.
4. The optical surface protective film with a separator according to claim 3, comprising 1 to 30 parts by weight of the aliphatic polyisocyanate crosslinking agent (B) with respect to 100 parts by weight of the (meth) acrylic polymer (A).
5. The optical surface protective film with a separator according to claim 3 or 4, wherein the pressure-sensitive adhesive composition further contains a catalyst (C) having iron or tin as an active center.
6. The optical with separator according to claim 5, comprising 0.002 to 0.5 parts by weight of the catalyst (C) having iron or tin as an active center with respect to 100 parts by weight of the (meth) acrylic polymer (A). Surface protective film.
   

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