TWI798348B - Adhesive sheet, optical member, and display device - Google Patents

Abstract

The object of the present invention is to provide an adhesive sheet (surface protection film) that can be adhered by combining a substrate with poor toughness and an adhesive layer that easily follows bends or unevenness. Optical components or display devices with curved or concave-convex parts of the body, and the display constituting the display device follow and fully protect the adherend during manufacturing, processing, handling, shipment inspection, and transportation. The solution is the adhesive sheet of the present invention, which is characterized in that: there is an adhesive layer formed of an adhesive composition on one or both sides of the base film; in the adhesive sheet, the base film is non-polyolefin It is a film; after cutting the above-mentioned adhesive sheet into a width of 50mm and a length of 100mm, fix it on a horizontal platform so that it protrudes 50mm in the direction of length, and its vertical sagging distance L at this time is more than 30mm; and, the above-mentioned After the surface of the adhesive layer is bonded to the glass, the peeling force when stretched in the direction of 90 degrees at a peeling speed of 1mm/min is more than 3.0gf/50mm.

Description

Adhesive sheet, optical member, and display device

The present invention relates to an adhesive sheet, especially a surface protection film. The surface protection film is suitable for the use of sticking to the surface of an optical member or a display device to protect the surface, and the like. Optical components include ITO films, polarizers, diffusion plates, brightness enhancement films, cover glass, organic EL panels, liquid crystal panels, etc., which are laminated together. Examples of the display device include a monitor, a television, a smartphone, and the like.

Background of the invention Generally, a surface protection film has the structure which provided the adhesive agent layer on the film-form base film (support body). The surface protection film is bonded to an optical member of an adherend or a display device including an optical member through the above-mentioned adhesive layer, and its purpose of use is to manufacture, process, etc. an optical member or an electronic member constituting a display device, etc. Protect the surface of optical components, etc. from damage or dirt during handling, shipment inspection, and transportation. Then, when actually the surface of the adhesive layer of the surface protection film is attached to an optical member or a display device for use, the surface protection film can be peeled off at a stage where it is no longer needed.

In addition, when attaching the surface protection film to an optical member or a display device including an optical member, or a display (screen) constituting a display device, from the viewpoints of handling properties during manufacturing and processing and attaching the surface protection film to a display, etc. , Substrates with thickness (such as polyethylene terephthalate, etc.) have been used.

However, when a surface protection film using a thick substrate is bonded to a display constituting a display device having a curved portion or a concave-convex portion, the surface protection film cannot follow the curved portion or the concave-convex portion due to the strong toughness of the substrate. bad condition.

On the other hand, as shown in Patent Documents 1 and 2, when non-stretched polypropylene (CPP) or polyethylene (PE) with poor toughness is used as the base material of the surface protection film, the defective appearance of so-called fish eyes has also occurred. characteristics, or defects cannot be confirmed during shipment inspection.

In addition, in recent years, the number of optical members or display devices having curved parts or concave-convex parts, and displays constituting the display devices have been increasing. In the manufacturing process or shipping process of displays, etc., it is necessary to follow and protect the above-mentioned curved parts or concave-convex parts. surface protection film.

prior art literature patent documents Patent Document 1: Japanese Patent No. 5326469 Patent Document 2: Japanese Patent No. 3936922

Summary of the invention The problem to be solved by the invention Therefore, the inventors of the present invention have found an adhesive sheet (surface protection film) as a result of intensive research in view of the above-mentioned facts. Or the adhesive layer on the curved surface of the concave-convex part can be combined in the optical member or display device with a curved part or concave-convex part of the adherend, and the display constituting the display device is equal to the manufacturing process, handling, shipment inspection, transportation, etc. Follow the adherend and fully protect the surface, so as to achieve the completion of the present invention.

means to solve problems That is, the adhesive sheet of the present invention is characterized in that it has an adhesive layer formed of an adhesive composition on one or both sides of the base film; in the adhesive sheet, the base film is a non-polyolefin film; After cutting the aforementioned adhesive sheet into a width of 50 mm and a length of 100 mm, fix it on a horizontal platform so that it protrudes 50 mm in the longitudinal direction, and its vertical sagging distance L at this time is more than 30 mm; and, the aforementioned adhesive layer After the surface is bonded to glass, the peeling force when stretched in a 90-degree direction at a peeling speed of 1mm/min is 3.0gf/50mm or more.

In the adhesive sheet of the present invention, the adhesive layer is preferably formed of an adhesive composition containing at least one adhesive selected from acrylic adhesives, urethane adhesives, and silicone adhesives.

In the adhesive sheet of the present invention, the tensile elastic modulus of the aforementioned non-polyolefin film is preferably lower than 1.5×10 ⁹ Pa.

In the adhesive sheet of the present invention, the aforementioned non-polyolefin-based film is preferably a polyester film.

The optical member of the present invention is preferably protected by the aforementioned adhesive sheet.

The display device of the present invention is preferably protected by the aforementioned adhesive sheet.

Invention effect The adhesive sheet of the present invention is an adhesive sheet by combining a substrate film that has poor toughness and can follow a curved surface such as a curved portion or a concave-convex portion, and an adhesive layer that has good adhesive properties to a curved surface such as a curved portion or a concave-convex portion. Adhesive sheet (surface protection film) with excellent protection performance can be obtained by following the optical member or display device of the curved part or concave-convex part, the display device constituting the display device, etc. it works.

form for carrying out the invention Embodiments of the present invention will be described in detail below.

＜Overall structure of adhesive sheet (surface protection film)＞ The adhesive sheet (surface protection film) disclosed here is generally suitable for the surface of the adhesive layer in the form of an adhesive tape, an adhesive label, an adhesive film, etc., as an optical member or a display device (or a display constituting a display device) etc. In particular, a surface protection film that protects the surface of a display during manufacturing, handling, shipment inspection, and transportation of a display having a curved portion or a concave-convex portion. The adhesive layer in the aforementioned adhesive sheet is typically formed continuously, but it is not limited to this form, and the adhesive layer may be formed in regular or random patterns such as dots and stripes. In addition, the adhesive sheet disclosed here may also be in the form of a roll or a sheet.

＜Base Film＞ The adhesive sheet of the present invention is characterized by having a base film, and the base film is a non-polyolefin film. The toughness of polyolefin-based films is worse than that of non-polyolefin-based films. We speculate that the reason for the poor toughness is due to the lack of unsaturated bonds and the failure to restrict the rotation of carbon chains. However, when a polyolefin-based film is used as a base film constituting a surface protection film, it is not suitable because of poor appearance characteristics called fish eyes or failure to identify defects during shipment inspection. In addition, fish-eye refers to transparent or translucent fish-eye-like particles remaining in the base film during the film-forming step of the base film, which is caused by gel or unmelted resin. When polyolefin film is used as the base film, the melt viscosity of the resin is high, and it cannot pass through a high-precision filter during the film forming step, so unmelted material cannot be removed and there is a tendency to contain many fish eyes, so it is not suitable. Especially in the case of polyethylene, if free radicals are generated in the molecules when the resin is melted, the polyethylene molecules will react with each other and tend to gel, so many fish eyes will be produced, making it difficult to apply to optical applications, so it is not suitable. On the other hand, the non-polyolefin film has a low melt viscosity, so it can pass through a high-precision filter during film formation, so it can remove unmelted matter that causes fisheyes, so it can obtain a film with excellent appearance characteristics and is suitable for optical applications. use.

The above-mentioned base film (substrate, support) is a non-polyolefin-based film, such as a resin containing the following substances as the main resin component (the main component of the resin component, typically accounting for 50% by mass or more) It is better to use a plastic film made of materials as the aforementioned substrate film: polyester series such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, etc. Polymers; cellulosic polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate polymers; acrylic polymers such as polymethyl methacrylate, etc. Among them, the above-mentioned non-polyolefin-based film is preferably a polyester film using a polyester-based polymer, and among them, optical properties (transparency, etc.), mechanical strength, thermal stability, moisture shielding properties, isotropy, A film with excellent properties such as flexibility and dimensional stability. In particular, by imparting flexibility to a polyester film that is not too tough as a base film, the adhesive composition can be applied with a roll coater or the like and wound up into a roll, which is very useful. Moreover, the polyester film which has 2 or more types of ester bonds can also be used, and what combined polyethylene terephthalate and polybutylene terephthalate is used suitably.

Other examples of the aforementioned resin materials include the following materials as resin materials: styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers; vinyl chloride-based polymers; nylon 6, nylon 6,6, aromatic Amide-based polymers such as polyamide, etc. Other examples of the aforementioned resin material include imide-based polymers, sulfide-based polymers, polyether-sulfur-based polymers, polyetheretherketone-based polymers, polyphenylene sulfide-based polymers, vinyl alcohol-based polymers, Chlorinated vinylene-based polymers, vinyl butyral-based polymers, arylate-based polymers, polyoxymethylene-based polymers, epoxy-based polymers, and the like. A base film composed of a blend of two or more of the aforementioned polymers may also be used.

In the adhesive sheet of the present invention, the tensile elastic modulus of the aforementioned non-polyolefin-based film is preferably lower than 1.5×10 ⁹ Pa, preferably below 1.3×10 ⁹ Pa, more preferably 1.0×10 ⁷ ~1.3×10 ⁹ Pa , 1.0×10 ⁸ ~1.3×10 ⁹ Pa is preferred. Since the aforementioned tensile modulus of elasticity is lower than 1.5×10 ⁹ Pa, a substrate film with poor toughness can be used to some extent, so that it can easily follow the curved portion or concave-convex portion of the display, etc., making it an ideal aspect . In addition, if the tensile elastic modulus of the above-mentioned non-polyolefin-based film is more than 1.5×10 ⁹ Pa, the toughness of the base film will become too strong, and it may not be able to follow the curved portion or concave-convex portion of the display. suitable.

Various additives such as antioxidants, ultraviolet absorbers, plasticizers, colorants (pigments, dyes, etc.) may also be mixed with the resin material constituting the aforementioned base film as required. For example, well-known or customary surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and primer coating can be applied. The surface treatment may be, for example, a treatment for improving the adhesion between the base film and the adhesive layer (the anchoring property of the adhesive layer).

Aforesaid substrate film also can use the polyester film that has been made through antistatic treatment. The antistatic treatment can be applied to either the surface of the substrate film that is in contact with the adhesive layer or the surface of the substrate film that is not in contact with the adhesive layer. By using the above-mentioned base film, since the static electricity of the adhesive sheet (surface protection film) itself is suppressed at the time of peeling, it is preferable. In addition, the base film is a polyester film, and by applying antistatic treatment to the above polyester film, the static electricity of the adhesive sheet (surface protection film) itself can be reduced, and the antistatic performance to the adherend can be obtained. Adhesive sheet (surface protection film). In addition, the method of imparting antistatic function is not particularly limited, and conventional methods can be used, such as coating an antistatic resin composed of an antistatic agent and a resin component, or a conductive resin containing a conductive polymer or a conductive substance method, or the method of vapor-depositing or electroplating conductive substances, and the method of mixing antistatic agents.

The thickness of the aforementioned substrate film is usually 5-200 μm, preferably about 8-150 μm, more preferably 10-100 μm, more preferably about 13-100 μm. When the thickness of the aforementioned base film is within the aforementioned range, it is preferable in terms of workability of attaching to a to-be-attached object, detachability and workability from an adhering object.

＜Adhesive layer＞ The adhesive sheet of the present invention is characterized in having an adhesive layer formed of an adhesive composition on one or both sides of the base film. The adhesive layer used in the present invention is not particularly limited as long as it is formed of an adhesive composition containing an adhesive polymer having adhesive properties. For the aforementioned adhesive composition, for example, acrylic adhesives, urethane adhesives, synthetic rubber adhesives, natural rubber adhesives, silicone adhesives, polyester adhesives, etc. can be used. (Containing) At least one kind selected from the group consisting of acrylic adhesives, urethane adhesives, and silicone adhesives is preferable, and it is particularly preferable to use ( Adhesive composition of meth)acrylic polymer.

＜Acrylic adhesive＞ When an acrylic adhesive is used for the aforementioned adhesive layer, in terms of the (meth)acrylic polymer constituting the adhesive polymer of the aforementioned acrylic adhesive, a raw material monomer constituting the polymer can use a carbon number of 1 to 14. Alkyl (meth)acrylic monomers are used as main monomers. Moreover, the said (meth)acrylic-type monomer can use 1 type or 2 or more types. By using the above-mentioned (meth)acrylic monomer having an alkyl group having 1 to 14 carbons, it is easy to control the peeling force (adhesive force) to the adherend (protected body) to a low adhesive force, and it is possible to An adhesive sheet (surface protection film) excellent in light peelability or re-peelability is obtained. In addition, the (meth)acrylic polymer in the present invention means an acrylic polymer and/or a methacrylic polymer, and the methacrylate means an acrylate and/or a methacrylate.

Specific examples of the above-mentioned (meth)acrylic monomers having an alkyl group having 1 to 14 carbons can be enumerated such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, Secondary butyl (meth)acrylate, tertiary butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ( n-octyl methacrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, iso-(meth)acrylate Decyl ester, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, etc.

Among them, when the adhesive sheet of the present invention is used as a surface protection film, n-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylate, Base) n-octyl acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate (meth)acrylic monomers with alkyl groups with 4~14 carbons, such as ester, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, etc. . In particular, by using a (meth)acrylic monomer having an alkyl group having 4 to 14 carbons, it is easy to control the peeling force (adhesive force) to the adherend to a low adhesive force, and become re-peelable Excellence.

In particular, the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms contains at least 40% by weight relative to 100% by weight of the total monomer components constituting the (meth)acrylic polymer. Preferably, more than 45% by weight, more preferably 45-99% by weight, most preferably 50-98% by weight. If it is outside the above range, the moderate wettability of the adhesive composition or the cohesion of the adhesive layer will be poor, which is not ideal.

Moreover, the said (meth)acrylic-type polymer can use the (meth)acrylic-type monomer containing a hydroxyl group as a raw material monomer. The aforementioned hydroxyl group-containing (meth)acrylic monomers may be used alone or in combination of two or more. By using the aforementioned hydroxyl group-containing (meth)acrylic monomer, it is possible to easily control the cross-linking of the adhesive composition, etc., and even improve the wettability due to flow and reduce the peeling force (adhesive force) at the time of peeling. The balance of the player can also be easily controlled.

The aforementioned hydroxyl-containing (meth)acrylic monomers can be exemplified as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylate base) 6-hydroxyhexyl acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl ) methacrylate, N-methylol (meth)acrylamide, etc.

The hydroxyl-containing (meth)acrylic monomer preferably contains not more than 20% by weight, more preferably not more than 0.1 to 15% by weight, relative to 100% by weight of the total monomer components constituting the (meth)acrylic polymer. , more preferably 1 to 10% by weight. When it is within the aforementioned range, the balance between the wettability of the adhesive composition and the cohesive force of the obtained adhesive layer can be easily controlled, so it is preferable.

Also, other polymerizable monomer components can be used to adjust the glass transition temperature of (meth)acrylic polymer or Exfoliating polymerizable monomers and the like are used so that the Tg is 0°C or lower (usually -100°C or higher).

In addition, the aforementioned (meth)acrylic polymer can use a carboxyl group-containing (meth)acrylic monomer as a raw material monomer. By using the above-mentioned carboxyl group-containing (meth)acrylic monomer, the adhesive force of the adhesive layer (adhesive sheet, surface protection film) can be suppressed from increasing over time, so that it has excellent re-peelability and prevents the increase in adhesive force. sex and workability. Also, the cohesive force and shearing force of the adhesive layer are good, which is very suitable.

Examples of the aforementioned carboxyl group-containing (meth)acrylic monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate. In particular, the carboxyl group-containing (meth)acrylic monomer contains acrylic acid, so the glass transition temperature (Tg) becomes higher and the cohesive force can be improved. The material has toughness so it will rebound, but the adhesive with high cohesion is not easy to deform and has excellent rebound resistance, so it is suitable.

Relative to 100% by weight of the total amount of monomer components constituting the aforementioned (meth)acrylic polymer, the aforementioned carboxyl group-containing (meth)acrylic monomer is preferably 20% by weight or less, preferably 1 to 15% by weight, and 2 ~12% by weight is more preferred. When it is within the aforementioned range, the balance between the wettability of the adhesive composition and the cohesive force of the obtained adhesive layer can be easily controlled, so it is preferable.

啉、乙烯基醚單體等有提升剝離力(黏著力)或作為交聯化基點功用之官能基的成分。其中，以使用含氰基之單體、含醯胺基之單體、含醯亞胺基之單體、含胺基之單體、及含N-丙烯醯基

啉等含氮之單體為佳。藉由使用含氮之單體，可確保適當的剝離力(黏著力)而不會產生浮起或剝落等，更可獲得具優異剪切力之黏著片材(表面保護薄膜)，故為有利。該等聚合性單體可使用1種或2種以上。In addition, other polymerizable monomers other than the above-mentioned raw material monomers can be used for the aforementioned (meth)acrylic polymer without particular limitation, as long as the characteristics of the present invention are not impaired. For example, other polymerizable monomers mentioned above can be used appropriately: cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, etc. Monomers containing amine groups, monomers containing amine groups, monomers containing epoxy groups, N-acryl groups

There are functional groups such as phenoline and vinyl ether monomers that enhance peeling force (adhesion) or serve as cross-linking base points. Among them, monomers containing cyano groups, monomers containing amide groups, monomers containing imide groups, monomers containing amine groups, and monomers containing N-acryl groups can be used.

Nitrogen-containing monomers such as morphine are preferred. By using a nitrogen-containing monomer, an appropriate peeling force (adhesive force) can be ensured without floating or peeling, and an adhesive sheet (surface protection film) with excellent shear force can be obtained, so it is advantageous . These polymerizable monomers may be used alone or in combination.

The aforementioned cyano group-containing monomers may, for example, be acrylonitrile or methacrylonitrile.

The aforementioned amide group-containing monomers include, for example, acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, N,N -Dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N,N'-methylenebisacrylamide, N,N -Dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, diacetoneacrylamide, etc.

The above-mentioned monomers containing imide groups include, for example: cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, methylene Succinimide, etc.

The aforementioned amine-containing monomers, for example: amine ethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl ( Meth)acrylate, etc.

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

The aforementioned aromatic vinyl monomers include, for example, styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrenes.

The aforementioned epoxy group-containing monomers may, for example, be glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, allyl glycidyl ether, and the like.

The aforementioned vinyl ether monomers include, for example, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

In the present invention, the other polymerizable monomer is preferably 0 to 30% by weight, more preferably 0 to 10% by weight, based on 100% by weight of the total monomer components constituting the (meth)acrylic polymer. The aforementioned other polymerizable monomers should be properly adjusted to obtain desired properties.

The monomer component of the above-mentioned (meth)acrylic polymer may further contain a reactive monomer containing an epoxy group.

Also, from the viewpoint of the compatibility of the compound containing the oxyalkylene group, the average addition mole number of the oxyalkylene unit of the above-mentioned reactive monomer containing the epoxy group group is preferably 1~40, 3~40 40 is better, 4~35 is more preferable, and 5~30 is especially preferable. When the above-mentioned average molar number of addition is 1 or more, the pollution reduction effect of the adherend (protected body) tends to be obtained more effectively. Also, when the above-mentioned average added mole number exceeds 40, the interaction with the oxyalkylene group-containing compound is large, and the viscosity of the adhesive composition tends to increase, making it difficult to apply, so it is not suitable. Furthermore, the end of the oxyalkylene chain can be the original hydroxyl group or be substituted with other functional groups.

The above-mentioned reactive monomers containing epoxy group can be used alone, or two or more kinds can be used in combination, and the overall content should be 0-20 wt. %, preferably 0 to 10% by weight. When the content of the reactive monomer containing an epoxy group exceeds 20% by weight, the pollution to the adherend will be increased, so it is not suitable.

The oxyalkylene units of the above-mentioned reactive monomers containing epoxy groups can include those with 1 to 6 carbon atoms, such as oxymethylene, oxyethylene, oxypropyl, oxy Butyl, etc. The hydrocarbon group of the oxyalkylene chain may be a straight chain or a branched chain.

In addition, the above-mentioned reactive monomer containing an oxirane group is preferably a reactive monomer having an oxirane group. By using a (meth)acrylic polymer containing a reactive monomer with an oxirane group as the base polymer, the compatibility between the base polymer and the compound containing an oxyalkylene group can be improved, and the infiltrated The condition of the sticky body will be appropriately suppressed, and a low-pollution adhesive composition can be obtained.

The aforementioned reactive monomers containing alkylene oxides can be, for example, alkylene oxide adducts of (meth)acrylic acid, or reactive substituents such as acryl, methacryl, and allyl in the molecule. Reactive surfactants, etc.

Specific examples of the aforementioned (meth)acrylic acid alkylene oxide adducts include, for example: polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, polyethylene glycol-polypropylene glycol (methyl) ) acrylate, polyethylene glycol-polybutylene glycol (meth)acrylate, polypropylene glycol-polybutylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxy Polyethylene glycol (meth)acrylate, butoxypolyethylene glycol (meth)acrylate, octyloxypolyethylene glycol (meth)acrylate, lauryloxypolyethylene glycol (meth)acrylate ) acrylate, stearoxy polyethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, octyloxy polyethylene glycol Diol-polypropylene glycol (meth)acrylate, etc.

Also, specific examples of the aforementioned reactive surfactants include, for example: anionic reactive surfactants with (meth)acryl or allyl groups, nonionic reactive surfactants, cationic reactive surfactants, Surfactants, etc.

The weight average molecular weight (Mw) of the aforementioned (meth)acrylic polymer is preferably 100,000 to 2 million, more preferably 200,000 to 1.5 million, more preferably 300,000 to 1.2 million, and especially preferably 300,000 to 1 million. , the most appropriate is 400,000 to 800,000. When the weight-average molecular weight is less than 100,000, the cohesive force of the adhesive layer tends to decrease, resulting in residual adhesive. On the other hand, when the weight-average molecular weight exceeds 2 million, the fluidity of the polymer decreases, and the wetting of the adherend (such as a polarizing plate) becomes insufficient, and there is a risk of a discrepancy between the adherend and the adhesive sheet (surface protection film). The tendency to cause swelling between adhesive layers. In addition, the weight average molecular weight refers to the one measured by GPC (Gel Permeation Chromatography).

Also, the glass transition temperature (Tg) of the aforementioned (meth)acrylic polymer is preferably -60 to 0°C, more preferably -50 to -10°C. When the glass transition temperature is higher than 0°C, the polymer is not easy to flow, and for example, the wetting of the polarizing plate of the optical member becomes insufficient, and there is a possibility of expansion between the polarizing plate and the adhesive layer of the adhesive sheet (surface protection film) The tendency of the cause. When the glass transition temperature (Tg) is lower than -60°C, the cohesive force of the adhesive becomes low, and for example, when it is attached to a curved surface such as a curved or concave-convex surface, the adhesive layer will float due to the repulsion of the substrate Propensity. By adjusting the aforementioned glass transition temperature (Tg) to the aforementioned range, an adhesive layer with balanced wettability and cohesive force can be easily obtained. In addition, the glass transition temperature of the (meth)acrylic polymer can be adjusted within the aforementioned range by appropriately changing the monomer components used or the composition ratio.

The polymerization method of the above-mentioned (meth)acrylic polymer is not particularly limited, and it can be polymerized by well-known methods such as solution polymerization, emulsion polymerization, block polymerization, suspension polymerization, etc., but especially from the viewpoint of workability, Or in terms of the characteristics of the adherend (protected body) such as low pollution, solution polymerization is a better form. In addition, the obtained polymer may be any of random copolymers, block copolymers, alternating copolymers, graft copolymers, and the like.

＜Urethane adhesive＞ When a urethane-based adhesive is used for the aforementioned adhesive layer, any appropriate urethane-based adhesive can be used. Such urethane-based adhesives are preferably those composed of urethane-based polymers that are adhesive polymers obtained by reacting polyols and polyisocyanate compounds. Examples of polyols include polyether polyols, polyester polyols, polycarbonate polyols, and polycaprolactone polyols. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, toluene diisocyanate, and hexamethylene diisocyanate.

＜Polysilicone Adhesive＞ When a silicone-based adhesive is used in the aforementioned adhesive layer, any appropriate silicone-based adhesive may be used. The polysiloxane-based adhesive is preferably a polysiloxane-based polymer obtained by blending or coagulating an adhesive polymer.

In addition, examples of the aforementioned silicone-based adhesives include addition reaction-curable silicone-based adhesives and peroxide-curable silicone-based adhesives. Among these polysiloxane-based adhesives, addition reaction-curable polysiloxane-based adhesives are preferable in view of not using peroxides (benzoyl peroxide, etc.) and generating no decomposition products.

For the hardening reaction of the aforementioned addition reaction-curable polysiloxane-based adhesive, if the case of obtaining a polyalkylpolysiloxane-based adhesive is taken as an example, it is generally used to make polyalkylhydrogensiloxane through a platinum catalyst. method of hardening.

<Oxyalkylene-Containing Compounds> The adhesive composition used in the present invention may also contain an oxyalkylene group-containing compound. With the compound containing an oxyalkylene group, the light release property can be exhibited. The oxyalkylene-containing compound may be an organopolysiloxane having an oxyalkylene chain or an oxyalkylene-containing compound not containing an organopolysiloxane.

Specific examples of the aforementioned organopolysiloxanes having an oxyalkylene chain, that is, specific examples of organopolysiloxanes having an oxyalkylene chain in the main chain, can be cited as commercially available under the trade name X-22- 4952, X-22-4272, X-22-6266, KF-6004, KF-889 (manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (manufactured by TORAY-Dow Corning Co., Ltd.), IM22 (manufactured by Asahi Kasei WACKER company), etc. In addition, the organosiloxanes having an oxyalkylene chain in the side chain include commercially available product names KF-351A, KF-352A, KF-353, KF-354L, KF-355A, and KF-615A. , KF-945, KF-640, KF-642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X -22-2516 (the above are made by Shin-Etsu Chemical Industry Co., Ltd.); FZ-2203, FZ-7001, SH8400, SH8700, SF8410, SF8422 (the above are manufactured by TORAY-Dow Corning); TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460 (manufactured by Momentive Performance Materials); BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (manufactured by BIG Chemie Japan), etc. These compounds may be used alone or in combination of two or more.

Specific examples of the aforementioned organopolysiloxane-free oxyalkylene-containing compounds include, for example: polyoxyalkylene alkylamines, polyoxyalkylene diamines, polyoxyalkylene fatty acid esters, Polyoxyalkylene sorbitol fatty acid ester, polyoxyalkylene alkyl phenyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene alkyl allyl ether, polyoxyalkylene alkyl Nonionic surfactants such as phenyl allyl ether; polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkyl ether phosphates, polyoxyalkylene alkylphenyl ether sulfates Salt, polyoxyalkylene alkyl phenyl ether phosphate salt and other anionic surfactants; others, cationic surfactants with polyoxyalkylene chains (polyoxyalkylene chains) or amphoteric surfactants Agents, polyether compounds with polyoxyalkylene chains (and derivatives thereof), acrylic compounds with polyoxyalkylene chains (and derivatives thereof), etc. In addition, a polyoxyalkylene chain-containing monomer can also be blended as a polyoxyalkylene chain-containing compound. These polyoxyalkylene chain-containing compounds may be used alone or in combination of two or more.

Specific examples of the polyether compound (polyether component) having the aforementioned polyoxyalkylene chain include block copolymers of polypropylene glycol (PPG)-polyethylene glycol (PEG), and block copolymers of PPG-PEG-PPG. Copolymer, PEG-PPG-PEG block copolymer, etc. Derivatives of the aforementioned polyether compounds with polyoxyalkylene chains include compounds containing oxypropylidene groups (PPG monoalkyl ethers, PEG-PPG monoalkyl ethers, etc.) Examples include acylated oxypropylidene-containing compounds (terminal acetylated PPG, etc.).

In addition, specific examples of the aforementioned acrylic compound having a polyoxyalkylene chain include (meth)acrylate polymers having an oxyalkylene chain. As for the aforementioned oxyalkylene group, the number of moles added to the oxyalkylene unit is preferably 1-50, preferably 2-30, and more preferably 2-20. In addition, the terminal of the aforementioned oxyalkylene chain may be an original hydroxyl group, or may be substituted with an alkyl group, a phenyl group, or the like.

The monomer component of the above-mentioned (meth)acrylate polymer having an oxyalkylene group is preferably a polymer containing (meth)acrylic alkylene oxide. As a specific example of the above-mentioned (meth)acrylic alkylene oxide, : The (meth)acrylic ester containing ethylene glycol can be exemplified as methoxy-diethylene glycol (meth)acrylate, methoxy-triethylene glycol (meth)acrylate and other methoxy- Polyethylene glycol (meth)acrylate type; Ethoxy-polyethylene glycol such as ethoxy-diethylene glycol (meth)acrylate, ethoxy-triethylene glycol (meth)acrylate, etc. (Meth)acrylate type; butoxy-diethylene glycol (meth)acrylate, butoxy-triethylene glycol (meth)acrylate, etc. Butoxy-polyethylene glycol (meth) Acrylate type; phenoxy-polyethylene glycol (meth)acrylate type such as phenoxy-diethylene glycol (meth)acrylate, phenoxy-triethylene glycol (meth)acrylate, etc.; 2-Ethylhexyl-polyethylene glycol (meth)acrylate, nonylphenol-polyethylene glycol (meth)acrylate type; methoxy-dipropylene glycol (meth)acrylate and other methoxy- Polypropylene glycol (meth)acrylate type, etc.

Moreover, other monomer components other than the said alkylene oxide (meth)acrylate can also be used for the said monomer component. Specific examples of other monomer components include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, secondary butyl (meth)acrylate, and tributyl (meth)acrylate. Grade butyl ester, 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, (meth) ) Acrylate and/or methacrylate having an alkyl group with 1 to 14 carbons, such as n-tridecyl acrylate and n-tetradecyl (meth)acrylate.

啉、乙烯基醚類等。Furthermore, other monomer components other than the aforementioned alkylene oxide (meth)acrylate can be suitably used, for example: carboxyl group-containing (meth)acrylate, phosphoric acid group-containing (meth)acrylate, cyano group-containing (meth)acrylates, vinyl esters, aromatic vinyl compounds, (meth)acrylates containing anhydride groups, (meth)acrylates containing hydroxyl groups, (meth)acrylates containing amide groups, Amino-containing (meth)acrylate, epoxy-containing (meth)acrylate, N-acryl

phylloline, vinyl ethers, etc.

＜Crosslinking agent＞ The adhesive sheet of the present invention preferably contains a crosslinking agent in the aforementioned adhesive composition. Also, in the present invention, the above-mentioned adhesive composition can be used as an adhesive layer. For example, when the aforementioned adhesive composition is an acrylic adhesive containing the aforementioned (meth)acrylic polymer, it is appropriate to adjust the constituent units, constituent ratios, crosslinking agent selection and By adding ratios and crosslinking, an adhesive layer (adhesive sheet, surface protection film) that is more excellent in heat resistance and conformability to curved surfaces such as curved parts or uneven parts can be obtained.

The crosslinking agent used in the present invention can use isocyanate compounds, epoxy compounds, melamine resins, aziridine derivatives and metal chelate compounds, etc., especially the use of epoxy compounds can improve the cohesive force of the adhesive, which is an ideal form. . Moreover, these compounds may be used individually, and may mix and use 2 or more types.

二

三酮(oxadiazinetrione)鍵等改質之聚異氰酸酯改質體。市售品可舉如商品名TAKENATE300S、TAKENATE500、TAKENATE600、TAKENATED165N、TAKENATED178N(以上為三井化學公司製)、Sumidur T80、Sumidur L、Desmodur N3400(以上、住化Bayer Urethane公司製)、Millionate MR、Millionate MT、Coronate L、Coronate HL、Coronate HX(以上為TOSOH CO.製)等。該等異氰酸酯化合物可單獨使用，亦可混合2種以上使用，亦可併用2官能異氰酸酯化合物與3官能以上之異氰酸酯化合物使用。藉由併用交聯劑，能兼顧黏著性與耐反彈性(對如彎曲部或凹凸部之曲面的黏著性)，可獲得黏著可靠性更優異的黏著劑層(黏著片材、表面保護薄膜)。The aforementioned isocyanate compounds include, for example, aliphatic polyisocyanates such as trimethylene diisocyanate, butanediol diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, cyclopentylene diisocyanate, Cyclohexyl diisocyanate, isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane and other alicyclic isocyanates, 2,4-toluene diisocyanate, 4,4'- Aromatic isocyanates such as diphenylmethane diisocyanate and diisocyanate (XDI), the aforementioned isocyanate compounds in the form of allophanate bonds, diurea bonds, isocyanuric acid bonds, uretdione bonds, urea bonds, Carbodiamide bond, uretone imine bond,

two

Modified polyisocyanate modified by triketone (oxadiazinetrione) bond. Commercially available products include trade names TAKENATE300S, TAKENATE500, TAKENATE600, TAKENATED165N, TAKENATED178N (manufactured by Mitsui Chemicals), Sumidur T80, Sumidur L, Desmodur N3400 (manufactured by Sumika Bayer Urethane), Millionate MR, Millionate MT , Coronate L, Coronate HL, Coronate HX (the above are manufactured by TOSOH CO.), etc. These isocyanate compounds may be used alone or in combination of two or more, or a bifunctional isocyanate compound and a trifunctional or higher isocyanate compound may be used in combination. By using a crosslinking agent in combination, both adhesiveness and rebound resistance (adhesion to curved surfaces such as curved parts or uneven parts) can be achieved, and an adhesive layer (adhesive sheet, surface protection film) with better adhesion reliability can be obtained .

Aforementioned epoxy compounds can be for example: N, N, N ', N'-tetraepoxypropyl-m-xylylenediamine (trade name TETRAD-X, manufactured by Mitsubishi Gas Chemical Co.) or 1,3-bis( N,N-Diglycidylaminomethyl)cyclohexane (trade name TETRAD-C, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and the like.

The aforementioned melamine-based resin can be exemplified by hexamethylolmelamine and the like. Examples of the aziridine derivatives include commercially available products under the trade names of HDU, TAZM, and TAZO (above, manufactured by Mutual Pharmaceutical Co., Ltd.).

The metal components of the aforementioned metal chelate compounds can be exemplified by aluminum, iron, tin, titanium, nickel, etc., and the chelated components can be exemplified by acetylene, acetyl methyl acetate, ethyl lactate, etc.

The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 20 parts by weight relative to 100 parts by weight of the aforementioned (meth)acrylic polymer, preferably 0.1 to 18 parts by weight, more preferably 0.5 to 15 parts by weight, and 1 ~12 parts by weight is optimal. When the aforementioned content is less than 0.01 parts by weight, the formation of crosslinks by the crosslinking agent is not sufficient, the cohesive force of the obtained adhesive layer becomes small, and sufficient heat resistance may not be obtained, and it may cause residual glue. And when it is attached to a curved surface such as a curved portion or a concave-convex portion, the rebound resistance tends to be poor. On the other hand, when the content is greater than 20 parts by weight, the cohesive force of the polymer is large, the fluidity is reduced, and the wetting of the adherend (such as a polarizing plate) becomes insufficient, and there is a tendency to form a bond between the adherend and the adhesive layer (adhesive). The tendency to cause swelling between agent composition layers). In addition, by using the crosslinking agent within the above range, it is possible to achieve a balance between wettability and rebound resistance, and to easily obtain an adhesive layer excellent in followability to curved portions or concave-convex portions, which is an ideal aspect. These crosslinking agents may be used individually, or may mix and use 2 or more types.

＜Crosslinking catalyst＞ The aforementioned adhesive composition may further contain a cross-linking catalyst, which can make any of the above-mentioned cross-linking reactions proceed more efficiently. The cross-linking catalyst can be, for example, tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, ginseng (acetylacetonate) iron, ginseng (hexa-2,4-dione) iron, ginseng (Heptyl-2,4-dione) iron, ginseng (heptyl-3,5-dione) iron, ginseng (5-methylhexan-2,4-dione) iron, ginseng (octyl-2,4- Diketone) iron, ginseng (6-methylheptan-2,4-dione) iron, ginseng (2,6-dimethylheptane-3,5-dione) iron, ginseng (nonyl-2,4- Diketone) iron, ginseng (nonyl-4,6-dione) iron, ginseng (2,2,6,6-tetramethylheptane-3,5-dione) iron, ginseng (tridecane-6, 8-diketone) iron, ginseng (1-phenylbutyl-1,3-dione) iron, ginseng (hexafluoroacetylacetone) iron, ginseng (ethyl acetate) iron, ginseng (acetoacetate- n-Propyl) iron, ginseng (isopropyl acetoacetate) iron, ginseng (acetoacetate-n-butyl) iron, ginseng (acetoacetate-second butyl) iron, ginseng (acetoacetate-third Butyl) iron, ginseng (methyl propionyl acetate) iron, ginseng (ethyl propionyl acetate) iron, ginseng (propionyl acetate-n-propyl) iron, ginseng (isopropyl propionyl acetate) iron, ginseng ( Propionyl acetate - n-butyl) iron, ginseng (propionyl acetate - second butyl) iron, ginseng (propionyl acetate - third butyl) iron, ginseng (acetyl acetate benzyl) iron, ginseng (propionyl acetate) iron Dimethyl) iron diacid, ginseng (diethyl malonate) iron, trimethoxy iron, triethoxy iron, triisopropoxy iron, second iron chloride and other iron-based catalysts. These crosslinking catalysts may be used alone or in combination of two or more.

The content of the aforementioned crosslinking catalyst is not particularly limited, for example, relative to 100 parts by weight of the aforementioned (meth)acrylic polymer, it is preferably about 0.0001-1 part by weight, more preferably 0.001-0.5 part by weight. When it is within the above-mentioned range, the crosslinking reaction speed is fast when forming the adhesive layer, and the service life of the adhesive composition is also prolonged, which is a preferable aspect.

Furthermore, the aforementioned adhesive composition may also contain other well-known additives, such as powders such as slip agents, colorants, pigments, plasticizers, tackifiers, low molecular weight polymers, etc., depending on the application. Surface lubricant, leveling agent, antioxidant, preservative, light stabilizer, ultraviolet absorber, polymerization inhibitor, silane coupling agent, antistatic agent, inorganic or organic filler, metal powder, granular, foil wait.

＜Adhesive sheet (surface protection film)＞ The adhesive sheet (surface protection film) of the present invention is characterized in that it has an adhesive layer formed of an adhesive composition on one or both sides of the base film. At this time, the crosslinking of the adhesive composition generally depends on coating After the adhesive composition is carried out, the cross-linked adhesive layer composed of the adhesive composition can also be transferred to the base film or the like.

Also, the method of forming the adhesive layer on the base film is not particularly limited, for example, by coating the above-mentioned adhesive composition (solution) on the base film, drying and removing the polymerization solvent, etc., and then forming the adhesive on the base film layer to make. Thereafter, curing may be performed for the purpose of adjusting the migration of components of the adhesive layer or adjusting the crosslinking reaction. In addition, when coating the adhesive composition on the base film to produce an adhesive sheet, one or more solvents other than the polymerization solvent may be added to the above adhesive composition to uniformly coat the base film.

Moreover, the well-known method used for the manufacture of adhesive tapes can be used for the formation method of the adhesive layer at the time of manufacturing the adhesive sheet of this invention. Specifically, examples thereof include roll coating, gravure coating, reverse roll coating, roll brush, spray coating, air knife coating, extrusion coating using a die coater, and the like.

In the adhesive sheet of the present invention, the thickness of the aforementioned adhesive layer is usually made to be 3-100 μm, preferably about 5-30 μm. When the thickness of the adhesive layer is within the above-mentioned range, it is easy to obtain an appropriate balance between re-peelability and adhesiveness.

Also, the total thickness of the adhesive sheet of the present invention is preferably 8-300 μm, more preferably 10-200 μm, most preferably 20-100 μm. When it is in the said range, adhesive characteristics (removability, adhesiveness, etc.), workability, and appearance characteristics are excellent, and it becomes a preferable aspect. In addition, the above-mentioned total thickness means the total thickness value of all layers including a base film, an adhesive layer, a separator, and other layers.

＜Separate parts＞ The adhesive sheet disclosed here can take the form of an adhesive product with a separator (release liner) attached to the surface of the adhesive layer for the purpose of protecting the adhesive surface. Therefore, according to the present specification, there can be provided an adhesive sheet with a separator (adhesive product) comprising any one of the adhesive sheets disclosed herein and a separator for protecting the adhesive surface of the adhesive sheet.

The separator is not particularly limited. For example, it can be used: a separator with a release layer on the surface of a substrate such as a resin film or paper (it can be paper laminated with a resin such as polyethylene), or a separator made of a fluorine-based polymer (polyethylene). Tetrafluoroethylene, etc.) or polyolefin-based resins (polyethylene, polypropylene, etc.) low-adhesion materials such as separators made of resin films. Depending on the superior surface smoothness, a separator having a release layer on the surface of a resin film as a substrate, or a separator made of a resin film formed of a low-adhesion material can be suitably used. The resin film is not particularly limited as long as it can protect the adhesive layer, examples include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, Vinyl chloride copolymer film, polyester film (PET film, PBT film, etc.), polyurethane film, ethylene-vinyl acetate copolymer film, etc. For the formation of the above-mentioned peeling layer, for example, silicone-based peeling agents, long-chain alkyl-based peeling agents, olefin-based peeling agents, fluorine-based peeling agents, fatty acid amide-based peeling agents, molybdenum sulfide, Known release treatment agents such as silicon powder. It is especially advisable to use a polysiloxane-based release treatment agent. The thickness of the peeling treatment agent is not particularly limited, and it is usually about 0.01-1 μm, preferably about 0.1-1 μm.

The thickness of the separator is not particularly limited, and generally about 5-200 μm (for example, about 10-100 μm, preferably about 20-80 μm) is appropriate. When the thickness of the separator is within the above-mentioned range, it is preferable because the bonding workability to the adhesive layer and the peeling workability from the adhesive layer are excellent.

The base material for the aforementioned separator may be subjected to various surface treatments such as corona discharge treatment or various surface treatments such as embossing as required. Also, fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, colorants (pigments, dyes, etc.) ) and other additives.

Antistatic treatment may also be applied to the release treatment agent surface or the surface to which the release treatment agent has not been applied of the aforementioned separator.

The adhesive sheet (surface protection film) disclosed herein may also include other layers in addition to the base film, the adhesive layer, and the separator. Examples of the above-mentioned other layers include a primer layer (anchor layer) that can improve the anchoring properties of the antistatic layer or the adhesive layer.

The adhesive sheet of the present invention is characterized in that: after the aforementioned adhesive sheet is cut into a width of 50 mm and a length of 100 mm, it is fixed on a horizontal platform so that it protrudes 50 mm toward the length direction, and its vertical drooping distance L at this time is 30mm or more; and, after bonding the surface of the adhesive layer to glass, the peeling force (low-speed peeling force) when stretched in a 90-degree direction at a peeling speed of 1mm/min is 3.0gf/50mm or more. By setting the vertical sag distance L above 30mm, a base film with poor toughness will be used. Therefore, when it is attached to a curved surface such as a curved part or a concave-convex part, the rebound of the base film will be poor and the followability will be improved. , is more appropriate. In addition, the greater the low-speed peeling force, the higher the cohesive force of the adhesive, so when it is attached to a curved surface such as a curved part or a concave-convex part, it has excellent rebound resistance and good adhesion to curved surfaces. In particular, by setting the low-speed peeling force to 3.0gf/50mm or more, even if it is bonded to a curved surface such as a curved portion or a concave-convex portion, it is suitable to be in a state of being able to adhere without floating. In addition, the aforementioned vertical drooping distance L is preferably more than 32 mm, preferably 32-50 mm, and more preferably 34-49 mm. Moreover, the aforementioned peeling force should be above 4gf/50mm, preferably 6~30gf/50mm, and more preferably 8~15gf/50mm. If the upper limit of the aforementioned peeling force is 30 gf/50 mm or less, the peeling force (adhesive force) will not become too high, and the re-peelability is excellent, which is a preferable aspect.

＜Optical components＞ The optical member of the present invention is preferably protected by the aforementioned adhesive sheet. In the present invention, the surface of the pressure-sensitive adhesive layer of the aforementioned pressure-sensitive adhesive sheet (surface protection film) is attached to the optical member to protect the optical member. Moreover, since the followability with respect to a curved part or a concave-convex part is good, it can be used effectively for protecting the surface of the optical member which has a curved part or a concave-convex part.

＜Display device＞ The display device of the present invention is preferably protected by the aforementioned adhesive sheet. In the present invention, the display device or the display can be protected by attaching the surface of the adhesive layer of the above-mentioned adhesive sheet (surface protection film) to the surface of the display device or the display (screen) constituting the display device. Moreover, since the followability to the curved portion or the concave-convex portion is good, the surface of the display device or the display having the curved portion or the concave-convex portion can be effectively protected. Example

Various embodiments related to the present invention will be described below, but those shown in these specific examples are not intended to limit the present invention. In addition, the "part" and the symbol "%" in the following description are based on weight unless otherwise specified. It also indicates the blending amount (addition amount) in the table. In addition, in the measurement (evaluation), unless the measurement conditions (temperature, humidity, and time) are specified, the measurement (evaluation) was performed after standing at 23° C.×50% RH for 30 minutes.

In addition, each characteristic in the following description was measured and evaluated in the following manner, respectively.

＜Measurement of glass transition temperature (Tg) of (meth)acrylic polymer＞ The glass transition temperature (Tg) (° C.) was obtained by the following formula using the following document value of the glass transition temperature Tgn (° C.) of the homopolymer of each monomer. Formula: 1/(Tg+273)=Σ[Wn/(Tgn+273)] (In the formula, Tg (°C) represents the glass transition temperature of the copolymer, Wn (-) represents the weight fraction of each monomer, Tgn (°C) represents the glass transition temperature of the homopolymer of each monomer, n represents the type of body). Literature value: 2-ethylhexyl acrylate (2EHA): -70°C Butyl Acrylate (BA): -55°C Vinyl acetate (VAc): 32°C 2-Hydroxyethyl Acrylate (HEA): -15°C Acrylic acid (AA): 106°C In addition, the literature value refers to "Synthetic Design and New Application Development of Acrylic Resin" (issued by the Publishing Department of the Central Management and Development Center).

<Measurement of weight average molecular weight (Mw) of (meth)acrylic polymer> The weight average molecular weight (Mw) of the (meth)acrylic polymer used was measured using the GPC apparatus (HLC-8220GPC) by Tosoh Corporation. The measurement conditions are as follows. Sample concentration: 0.2% by weight (THF solution) Sample injection volume: 10μl Eluent: THF Flow rate: 0.6ml/min Measuring temperature: 40°C String: Sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2) Reference column; TSKgel SuperH-RC (1 piece) Detector: Differential Refractometer (RI) In addition, weight average molecular weight was calculated|required as the polystyrene conversion value.

＜Tensile modulus of base film＞ After cutting various substrate films into samples with a width of 15 mm and a length of 50 mm, tensile tests were performed on the samples at an environment of 23°C×50% RH with a distance between clamps of 20 mm and a tensile speed of 100 mm/min (Shimadzu Manufactured by Seisakusho, Tensile Testing Machine (Universal Testing Machine AG-20kNX), the amount of change (mm) caused by the elongation of the sample was measured. In this way, in the obtained S-S (Strain-Strength) curve, draw a tangent line on the initial rising part, and divide the tangent line equivalent to the tensile strength at 100% elongation by the cross-sectional area of each substrate film , with the obtained value as the tensile modulus of elasticity (Pa).

＜Bending stress of adhesive sheet＞ After cutting various adhesive sheets into 6mm in width and 50mm in length to make samples, put the samples on a 3-point bending fixture with a distance between fulcrums of 25mm, press-in speed 0.5 under the environment of 23℃×50%RH Indentation test (manufactured by TA Instruments, dynamic viscoelasticity measuring device RSA-III) was performed at mm/sec, and the load (g) when the sample was pressed into 5mm was measured as the bending stress of the adhesive sheet (evaluation ).

In the adhesive sheet of the present invention, the bending stress (load) of the aforementioned adhesive sheet is preferably 0.01-0.20 g, more preferably 0.03-0.18 g, more preferably 0.05-0.15 g. When the bending stress (load) of the adhesive sheet is within the aforementioned range, the toughness of the adhesive sheet is not too strong, and the followability becomes good, which is a preferable aspect. In addition, if the bending stress (load) exceeds 0.20 g, the toughness will become too strong and the followability will decrease, so it is not suitable.

<Vertical sagging distance L of the adhesive sheet> As shown in Figure 1, after standing in an environment of 23°C×50%RH for 30 minutes, the obtained adhesive sheet 1 was cut into a width of 50 mm and a length of 100 mm, and the surface of the adhesive layer constituting the adhesive sheet was attached to the Make it protrude 50mm toward the length direction on the horizontal fixing table 3, and place a 100g weight 2 on the adhesive sheet to fix it. Then, align the viewing angle with the height of the adhesive sheet from the thickness direction of the adhesive sheet, and use a ruler to measure the vertical sag distance L (mm). The measurement is carried out under the environment of 23°C×50%RH. Since the aforementioned vertical sagging distance L is more than 30mm, it is more suitable to use a base film with poor toughness. When it is attached to a curved surface such as a curved part or a concave-convex part, the rebound of the base film will be poor and the followability will become better.

＜Measurement of low-speed peel force＞ After cutting the obtained adhesive sheet into a width of 50 mm and a length of 100 mm, the surface of the adhesive layer constituting the adhesive sheet was bonded to the glass of the adherend at a speed of 0.25 MPa and 0.3 m/min. Qingban edge abrasive (OF1)), making evaluation samples. After bonding, let it stand in an environment of 23°C×50%RH for 30 minutes, and peel it off at a tensile speed of 1mm/min (low speed) with a tensile testing machine (Tensile compression testing machine TCM-1kNB manufactured by MinebeaMitsumi Inc.). Peel force (gf/50mm) was measured at an angle of 90 degrees. The measurement is carried out under the environment of 23°C×50%RH. Since the low-speed adhesive force is above 3.0gf/50mm, even if it is bonded to a curved surface such as a curved part or a concave-convex part, it will not float and become an adherent state.

＜Followability to the bending part＞ Using curved glass (manufactured by Nippon Sheet Glass Co., Ltd.) with a long side of 120 mm, a short side of 65 mm, a thickness of 0.55 mm, and a radius of curvature R=5 mm at the end and bent (downward) by 2 mm in the height direction, the evaluation of the followability of the curved part was performed. . First, cut the obtained adhesive sheet into the same size as the curved glass to make a sample, then attach the sample with a manual roller in an environment of 23°C×50%RH, and then observe with the naked eye whether there is any adhesion. Bend the curved part of the glass and evaluate it according to the following criteria. (Assessment basis) ○: The bent portion does not rise and is adhered. ×: A case where the bent portion floated up.

＜Appearance (whether there are dents or gels)＞ In order to visually observe the surface of the base film constituting the obtained adhesive sheet, measure the number of defects (dents and gels) within the observed range of 10 cm vertically x 10 cm horizontally of the obtained adhesive sheet, and evaluate according to the following criteria. The number of defects is 0 to 50: the appearance is good (○). The number of defects is 51 or more: Defective appearance (×).

＜Adjustment of (meth)acrylic polymer (A)＞ Feed 54 parts by weight of 2-ethylhexyl acrylate (2EHA), 43 parts by weight of vinyl acetate (VAc), and 3 parts by weight of acrylic acid (AA) into a four-necked flask equipped with stirring blades, a thermometer, a nitrogen gas inlet pipe, and a cooler , 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, 186 parts by weight of toluene, introducing nitrogen gas while slowly stirring, and keeping the liquid temperature in the flask at around 63°C A (meth)acrylic polymer (A) solution (about 35% by weight) was prepared by polymerization reaction for about 4 hours. The (meth)acrylic polymer (A) had a weight average molecular weight (Mw) of 470,000, and a glass transition temperature (Tg) of -21°C.

＜Preparation of (meth)acrylic polymer (B)＞ Feed 95 parts by weight of butyl acrylate (BA), 5 parts by weight of acrylic acid (AA), and 2,2'-azobis 0.1 parts by weight of isobutyronitrile, 234 parts by weight of ethyl acetate, introducing nitrogen gas while slowly stirring, and keeping the liquid temperature in the flask at around 65°C for 6 hours of polymerization reaction to prepare (meth)acrylic polymer ( B) Solution (about 30% by weight). The (meth)acrylic polymer (B) had a weight average molecular weight (Mw) of 600,000, and a glass transition temperature (Tg) of -47°C.

＜Adjustment of (meth)acrylic polymer (C)＞ 90 parts by weight of butyl acrylate (BA), 10 parts by weight of acrylic acid (AA), and 2,2'-azobis 0.1 parts by weight of isobutyronitrile, 234 parts by weight of ethyl acetate, introducing nitrogen gas while slowly stirring, and keeping the liquid temperature in the flask at around 65°C for 6 hours of polymerization reaction to prepare (meth)acrylic polymer ( C) Solution (about 30% by weight). The (meth)acrylic polymer (C) had a weight average molecular weight (Mw) of 610,000, and a glass transition temperature (Tg) of -40°C.

＜Preparation of (meth)acrylic polymer (D)＞ Feed 96 parts by weight of 2-ethylhexyl acrylate (2EHA) and 4 parts by weight of 2-hydroxyethyl acrylate (HEA) into a four-necked flask equipped with stirring blades, a thermometer, a nitrogen gas inlet pipe, and a cooler, as a polymerization initiator 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) and 205 parts by weight of ethyl acetate, introduce nitrogen gas while stirring slowly, and keep the liquid temperature in the flask at around 63°C for about 4 hours A (meth)acrylic polymer (D) solution (about 35% by weight) was prepared by a polymerization reaction. The (meth)acrylic polymer (D) had a weight average molecular weight (Mw) of 650,000, and a glass transition temperature (Tg) of -68°C.

[Preparation of acrylic adhesive (1) solution] 100 parts by weight of the solid content of the above-mentioned (meth)acrylic polymer (A) solution (about 35% by weight) was added as an epoxy-based cross-linking agent (1,3-bis(N,N-di Glycidylaminomethyl) cyclohexane, epoxy equivalent: 110, number of functional groups: 4, trade name "TETRAD-C": T/C, manufactured by MITSUBISHI GAS CHEMICAL) 2 parts by weight, and kept at 25 Mix and stir for about 1 minute at around °C to prepare an acrylic adhesive (1) solution.

[Preparation of acrylic adhesive (2) solution] Add the epoxy series crosslinking agent (1,3-bis(N,N-bicyclo Oxypropylaminomethyl)cyclohexane, epoxy equivalent: 110, number of functional groups: 4, trade name "TETRAD-C": T/C, manufactured by MITSUBISHI GAS CHEMICAL) 10 parts by weight, and kept at 25°C Mix and stir for about 1 minute to prepare an acrylic adhesive (2) solution.

[Preparation of acrylic adhesive (3) solution] Add an epoxy-based cross-linking agent (1,3-bis(N,N-bicyclo Oxypropylaminomethyl)cyclohexane, epoxy equivalent: 110, number of functional groups: 4, trade name "TETRAD-C": T/C, manufactured by MITSUBISHI GAS CHEMICAL) 6 parts by weight, and kept at 25°C Mix and stir for about 1 minute to prepare an acrylic adhesive (3) solution.

[Preparation of acrylic adhesive (4) solution] Add the epoxy series cross-linking agent (1,3-bis(N,N-bicyclo Oxypropylaminomethyl)cyclohexane, epoxy equivalent: 110, number of functional groups: 4, trade name "TETRAD-C": T/C, manufactured by MITSUBISHI GAS CHEMICAL) 11 parts by weight, and kept at 25°C Mix and stir for about 1 minute to prepare an acrylic adhesive (4) solution.

[Preparation of acrylic adhesive (5) solution] Add an isocyanate-based cross-linking agent (trimethylolpropane/toluene diisocyanate 3 polymer addition product, trade name "Coronate L": C/L, manufactured by TOSOH CO.) 4 parts by weight, dibutyltin dilaurate (manufactured by Tokyo Fine Chemical CO., LTD., trade name: EMBILIZER OL- 1. "Sn" in Table 3, 0.5% by weight ethyl acetate solution): 0.015 parts by weight, and kept at around 25°C for about 1 minute for mixing and stirring to prepare an acrylic adhesive (5) solution.

[Preparation of urethane-based adhesive (6) solution] Add 100 parts by weight of PREMINOL S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000) as a polyol having three hydroxyl groups, and an adduct of hexamethylene diisocyanate (Coronate HL: C/HL, manufactured by TOSOH CO.) 7.4 parts by weight, iron (III) acetylacetonate as a catalyst (see (acetylacetonate) iron), "Fe" in Table 4, manufactured by Tokyo Chemical Industry Co., Ltd.) 0.12 parts by weight, 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 210 parts by weight of ethyl acetate as a diluting solvent were kept at around 25°C for about 1 minute and mixed to obtain a urethane-based adhesive (6) Solution.

[Preparation of silicone adhesive (7) solution] SD4587 L PSA (solid content 40% by weight, manufactured by TORAY-Dow Corning Co., Ltd.) to which 100 parts by weight of a silicone-based polymer was added as a silicone-based adhesive, NX-35 Catalyst (TORAY-Dow Corning Co.) 0.5 parts by weight as a catalyst and 100 parts by weight of toluene as a diluting solvent were kept at around 25° C. and mixed for about 1 minute to obtain a polysiloxane-based adhesive (7) solution.

<Example 1> The above-mentioned acrylic adhesive solution (1) was coated on the substrate film I (polyethylene terephthalate, thickness: 19 μm, tensile elastic modulus: 1.2×10 ⁹ Pa, trade name : DIAFOIL T100-19B: manufactured by Mitsubishi Chemical Corporation), and heated at 130° C. for 2 minutes to form an adhesive layer with a thickness of 10 μm to prepare an adhesive sheet.

＜Example 2~4＞ As shown in Table 6, except that the acrylic adhesive (2)-(4) solution was used instead of the acrylic adhesive (1) solution used in Example 1, an adhesive sheet was prepared in the same manner as in Example 1.

<Example 5> As shown in Table 6, except that the substrate film II (polyethylene terephthalate, thickness: 12 μm, tensile elastic modulus: 1.0×10 ⁹ Pa, trade name: Lumirror #12S10 was used: Toray Co., Ltd.) was substituted for the substrate film used in Example 1, and an adhesive sheet in which the heating conditions, etc., and the thickness of the obtained adhesive layer were adjusted was produced in the same manner as in Example 1.

<Example 6> As shown in Table 6, except that the substrate film III (polyethylene terephthalate, thickness: 25 μm, tensile elastic modulus: 7.0×10 ⁸ Pa, trade name: ESR: Daizo Kogyo In the same manner as in Example 1, except that the substrate film used in Example 1 was replaced by the company (manufactured by the company), an adhesive sheet in which the heating conditions, etc., and the thickness of the obtained adhesive layer were adjusted was produced.

<Examples 7 and 8> As shown in Table 6, except that the solution of the acrylic adhesive (1) used in Example 1 was replaced by the solution of the urethane adhesive (6) or the solution of the polysiloxane adhesive (7), the same method as in the implementation In the same manner as in Example 1, an adhesive sheet was prepared in which the heating conditions, etc., and the thickness of the obtained adhesive layer were adjusted.

<Comparative Example 1> As shown in Table 6, except that the substrate film IV (polyethylene terephthalate, thickness: 38 μm, tensile elastic modulus: 2.0×10 ⁹ Pa, trade name: DIAFOIL T100C-38 : manufactured by Mitsubishi Chemical Corporation) except that the substrate film used in Example 1 was replaced, an adhesive sheet in which the heating conditions and the thickness of the obtained adhesive layer were adjusted was produced in the same manner as in Example 1.

<Comparative Example 2> After coating the acrylic adhesive (1) solution on a 38 μm polyethylene terephthalate film coated with silicone release treatment, dry it at 130°C for 2 minutes To obtain an adhesive layer. Then, the obtained adhesive layer was bonded (transferred) to the base film V (non-stretched polypropylene, thickness: 40 μm, tensile elastic modulus: 4.5×10 ⁸ Pa, trade name: MK-12: SunTox Co. , Ltd.) to obtain an adhesive sheet.

＜Comparative example 3＞ As shown in Table 6, except that the acrylic adhesive (5) solution was used instead of the acrylic adhesive (1) solution used in Example 1, the heating conditions, etc., and the obtained adhesive layer were prepared in the same manner as in Example 1. Adhesive sheet whose thickness has been adjusted.

Regarding the adhesive sheets of Examples and Comparative Examples, Table 1 to Table 6 list the above-mentioned content of blending, and the results of various measurements and evaluations. In addition, the blending amount in the table represents the active ingredient. In addition, the thickness of the adhesive layer was the same as in Example 1, and all of Examples and Comparative Examples were adjusted to be 10 μm.

[Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

It can be confirmed from the above Table 6 that in all the examples, the vertical sag distance L of the adhesive sheet is more than 30 mm, the low-speed peeling force is also within the expected range, and the bending stress of the adhesive sheet and the bending part (curved surface) ) is also good in followability. At the same time, the appearance of the substrate film is also good.

On the other hand, in Comparative Example 1, the vertical sagging distance L was less than 30 mm, and the bending stress of the adhesive sheet was also poor, so that the followability to the bent portion deteriorated. In Comparative Example 2, since a non-stretched polypropylene film of a polyolefin-based film was used, it was confirmed that the appearance was poor. In Comparative Example 3, although the vertical sag distance L was 30 mm or more, the low-speed peeling force was less than 3.0 gf/50 mm, and it was confirmed that the followability to the bending portion was poor.

Industrial availability The adhesive sheet disclosed here is suitable for manufacturing and transporting optical members used as components of liquid crystal display panels, plasma display panels (PDP), organic electroluminescence (EL) displays, etc., and display devices including optical members, etc. , as a surface protective film to protect the optical member.

1‧‧‧Adhesive sheet (surface protection film) 2‧‧‧weight 3‧‧‧fixed table L‧‧‧Vertical droop distance

Fig. 1 is a schematic diagram when measuring the vertical sag distance L of the adhesive sheet.

Claims (4)

An adhesive sheet, characterized in that: an adhesive layer formed of an adhesive composition is provided on one or both sides of a base film; in the adhesive sheet, the aforementioned base film is a non-polyolefin film; the aforementioned adhesive After the sheet is cut into a width of 50 mm and a length of 100 mm, fix it on a horizontal platform so that it protrudes 50 mm in the length direction, and its vertical sag distance L at this time is more than 30 mm; After reaching the glass, the peeling force when stretched in a 90-degree direction at a peeling speed of 1mm/min is more than 3.0gf/50mm and less than 30gf/50mm; the aforementioned adhesive layer is composed of acrylic adhesives, urethane Formed from an adhesive composition of at least one adhesive selected from adhesives and polysiloxane-based adhesives; the tensile elastic modulus of the aforementioned non-polyolefin-based film is lower than 1.5×10 ⁹ Pa. The adhesive sheet according to claim 1, wherein the non-polyolefin-based film is a polyester film. An optical member, characterized in that it is protected by the adhesive sheet according to claim 1 or 2. A display device, characterized in that it is protected by the adhesive sheet according to claim 1 or 2.

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