TWI677545B - Surface protection film - Google Patents

Abstract

The surface protection film of the present invention is used for protecting an optical member or an electronic member and is used to protect the surface. The surface protective film includes a substrate and an adhesive layer provided on one side of the substrate. The adhesive layer is made of acrylic acid. The acrylic copolymer (A) is a copolymer of an energy ray-curable adhesive composition of the copolymer (A). The acrylic copolymer (A) copolymerizes an alkyl group having 1 or 2 carbon atoms containing at least 5 to 50% by mass of an alkyl group ( A meth) acrylic acid ester is obtained without a carboxyl group-containing monomer or a monomer component containing less than 5% by mass of the carboxyl group-containing monomer.

Description

Surface protection film

The present invention relates to a surface protection film formed by laminating an adhesive on one side of a substrate, and is particularly a surface protection film for bonding to the surface of various optical components or electronic components for protecting the surface.

For the lens unit and communication of the camera. Motor units such as induction modules and vibrators, image modules, etc. For example, when unitized optical or electronic components are processed, assembled, inspected, or conveyed to prevent damage to the surface, they may be attached to the exposed surface. Surface protection film. The surface protection film can be peeled off from an optical member or an electronic member when no surface protection is required.

The optical member or the electronic member may be bonded under a surface protection film and connected to another member such as a substrate. However, a thermosetting adhesive may be used for the connection. At this time, when the optical member or the electronic member is to be cured by the adhesive, the surface protective film is generally heated under bonding, so for the surface protective film, it is required that the adhesive property or peeling property does not change much even if heated. By. For example, in order to meet such required characteristics, it is known to use acrylic acid as a main agent on the adhesive layer. Adhesive of a nitrogen-containing monomer of a copolymer (refer to Patent Document 1).

[Prior technical literature] [Patent Literature]

[Patent Document 1] JP 2006-332419

[Summary of Invention]

Therefore, the surface protection film may be inadvertently peeled off by punching or the like in the step. Therefore, in order to properly protect the bonded body, a high adhesive force is required and an optical member or an electronic member can be bonded. Especially in recent years, as the above-mentioned optical components or electronic components are gradually miniaturized, the size of the surface protection film is also reduced, so the surface protection film may be inadvertently peeled off, and its requirements are increasing.

In addition, the bonding and peeling of the surface protection film are generally performed manually, and even a small-sized film requires good workability. Specifically, it is required that the peeling performance at the time of peeling of the surface protective film be good. In addition, since the film has a small size, the position at the time of bonding is likely to vary, and the frequency of re-bonding correction is increased. Therefore, the ease of so-called reworkable bonding correction is also required.

In addition, the performance of optical components and electronic components is being improved, and it is required to reduce contamination caused by adhesives such as paste residues. For example, even a small amount of paste residue in lens parts such as image modules can cause a significant decrease in performance, so it is necessary to further improve the peeling performance.

For example, the surface protection film using the adhesive disclosed in Patent Document 1 does not have excellent adhesion, peelability, and reworkability, and the surface protection film must be further improved.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a surface protective film for an optical member or an electronic member having excellent adhesiveness, peelability, and reworkability.

As a result of detailed review, the present inventors found that when the energy ray hardening type of the adhesive for the surface protection film is used and the composition of the acrylic copolymer of the adhesive component is specified, the above problems can be solved and the following invention has been completed.

(1) A surface protection film, which is adhered to an optical member or an electronic member and is used to protect the surface, and is characterized by including a base material and an adhesive layer provided on one side of the base material, and the aforementioned adhesive The layer is made of an energy ray-curable adhesive composition containing an acrylic copolymer (A), and the acrylic copolymer (A) is copolymerized with at least 5 to 50% by mass of an alkyl group having a carbon number of 1 or The alkyl (meth) acrylate of 2 is obtained without a carboxyl group-containing monomer or a monomer component containing less than 5 mass% of the carboxyl group-containing monomer.

(2) The surface protection film according to the above (1), wherein the energy ray-curable adhesive composition further contains an energy ray polymerizable compound (B).

(3) The surface protection film according to the above (1), wherein the acrylic copolymer (A) is an energy ray-curable acrylic copolymer having an unsaturated group in a side chain.

(4) The surface protective film according to the above (1), wherein the acrylic copolymer (A) is an energy ray-curable acrylic copolymer having an unsaturated group in a side chain, and the energy ray-curable adhesive The composition further contains an energy ray polymerizable compound (B).

(5) The surface protective film according to the above (2) or (4), wherein the energy ray polymerizable compound (B) is a urethane acrylate-based oligomer.

(6) The surface protection film according to any one of (1) to (5) above, wherein the acrylic copolymer (A) is further copolymerized with a carbon number of 3 or more containing 30 to 85% by mass of an alkyl group. A monomer component of an alkyl (meth) acrylate.

(7) The surface protective film according to the above (6), wherein the alkyl (meth) acrylate having an alkyl group having a carbon number of 3 or more is an alkyl (meth) acrylic acid having an alkyl group having a carbon number of 3 to 8 ester.

(8) The surface protective film according to any one of (1) to (7) above, wherein the acrylic copolymer (A) is further copolymerized with a hydroxyl group-containing (meth) acrylic acid containing 0.2 to 40% by mass The monomer component of the ester.

(9) The surface protection film according to any one of (1) to (8) above, wherein the adhesive layer is an adhesive force before the energy ray irradiation is 1000 to 20000 mN / 25mm, and an adhesive force after the energy ray irradiation 0.1 ~ 100mN / 25mm.

(10) The surface protective film according to any one of (1) to (9) above, wherein the aforementioned adhesive layer is one whose initial adhesive force before energy beam irradiation is less than 10,000 mN / 25 mm.

(11) The surface protective film according to any one of (1) to (10) above, wherein after the aforementioned adhesive layer is colored, the light transmittance of the surface protective film becomes less than 50%.

(12) The surface protection film according to any one of (1) to (11) above, which is adhered to an image module and is used to protect a light receiving portion of the image module.

(13) A member with a surface protection film, comprising any member selected from an optical member or an electronic member, and any one of (1) to (12) described above bonded to the surface of the member. Surface protection film.

(14) A method for protecting a surface, which is characterized in that a surface protection film according to any one of (1) to (12) above is bonded to a surface of an optical member or an electronic member to protect the surface.

The present invention is to provide a surface protection film for an optical member or an electronic member having excellent adhesion, peelability, and reworkability.

[Mode for Carrying Out the Invention]

In the following description, "weight average molecular weight" The polystyrene conversion value measured by the gel permeation chromatography (GPC) method is specifically a value measured according to the method described in the examples.

For the description in this specification, for example, "(meth) acrylate" means both "acrylate" and "methacrylate", and other similar terms are also the same.

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

〔Surface protection film〕

The surface protection film of the present invention is adhered to an optical member or an electronic member, and is used for protecting the surface, and includes a substrate and an adhesive layer provided on one side of the substrate. Each component of the adhesive sheet is described below.

<Adhesive layer>

The adhesive layer of the present invention is made of an energy ray-curable adhesive composition containing an acrylic copolymer (A). The energy ray-curable adhesive composition is one that is hardened by irradiating the energy ray to reduce the adhesion. Specific examples of the energy rays include ultraviolet rays and electron rays, and ultraviolet rays are preferably used.

The acrylic copolymer (A) is generally a compound that imparts adhesiveness to an adhesive layer. The acrylic copolymer (A) is a copolymerized monomer component (hereinafter also referred to as a "copolymer component") containing an alkyl (meth) acrylate as a main monomer. Examples of the alkyl (meth) acrylate include those having 1 to 18 carbon atoms, and meth (meth) acrylate, ethyl (meth) acrylate, and isopropyl (methyl) Base) acrylate, n-propyl (meth) acrylate, butyl (meth) methacrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (methyl Acrylate), nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, and the like.

As the copolymer component of the acrylic copolymer (A), the content of the alkyl (meth) acrylate is generally 50% by mass or more, preferably 50 to 95% by mass, and more preferably the total content of the copolymer component. 60 to 90% by mass.

The acrylic copolymer (A) is used as a copolymer component, and the content of the alkyl (meth) acrylate having 1 or 2 carbon atoms in the alkyl (meth) acrylate is included in the total amount of the copolymer component. 5 to 50% by mass. When the content is less than 5% by mass, the adhesive force is particularly high after irradiation with energy rays, and there is a concern that the peeling performance may be reduced. If the initial adhesion is too high, sufficient reworkability cannot be obtained. When the content is higher than 50% by mass, the adhesive force may be insufficient, and the surface protective film may be inadvertently peeled off from the electronic member and the optical member in each step described later, and there is a concern that the electronic member and the optical member cannot be fully protected.

From the above viewpoint, as the copolymer component, the content of the alkyl (meth) acrylate having 1 or 2 carbon atoms in the alkyl group as the copolymer component is 10 based on the total amount of the copolymer component. It is preferably 40% by mass, and more preferably 15 to 35% by mass.

Examples of the alkyl (meth) acrylate having 1 or 2 carbon atoms in the alkyl group include meth (meth) acrylate and ethyl (meth) acrylate Among these, methacrylate and methmethacrylate are also preferable.

The acrylic copolymer (A) has a content of an alkyl (meth) acrylate having an alkyl group of 3 or more in the alkyl (meth) acrylate as a copolymer component with respect to the copolymer component. The total amount is preferably 30 to 85% by mass. When the content of the alkyl (meth) acrylate having an alkyl group having 3 or more carbon atoms is within such a range, it is possible to easily and appropriately impart adhesive properties and peeling properties to a surface protective film. From such a viewpoint, the content of the alkyl (meth) acrylate having 3 or more carbon atoms is preferably 40 to 80% by mass, and more preferably 45 to 75% by mass.

The alkyl (meth) acrylate having a carbon number of 3 or more is preferably an alkyl (meth) acrylate having a carbon number of 3 to 8 and the carbon number of the alkyl group is 4 Alkyl (meth) acrylates of 8 to 8 are more preferred, and alkyl acrylates of 4 to 8 carbons are more preferred. Specifically, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate and the like are preferable.

The acrylic copolymer (A) preferably contains a polymerizable monomer other than an alkyl (meth) acrylate as a copolymer component, and particularly preferably contains a functional group-containing monomer. The functional group-containing monomer is a functional group necessary to provide an unsaturated group-containing compound in the acrylic copolymer (A) as described later, or to react with a crosslinking agent as described later. The functional group-containing monomer is a monomer having a polymerizable double bond and functional groups such as a hydroxyl group, a carboxyl group, an amine group, a substituted amine group, and an epoxy group in the molecule.

Among them, the acrylic copolymer (A) of the present invention does not contain a carboxyl group-containing monomer as a copolymer component, or even contains a carboxyl group-containing monomer. The content of the monomer is less than 5% by mass based on the total amount of the copolymer component. When the carboxyl group-containing monomer is contained in an amount of 5% by mass or more, the adhesive force of the adhesive layer after irradiation with energy rays is excessively high, and there is a concern that the peelability of the surface protective film is deteriorated. In addition, if the initial adhesion is too high, there is a concern that the reworkability will decrease.

From these viewpoints, it is known that the content of the carboxyl group-containing monomer in the copolymer component is preferably less than 3% by mass, more preferably less than 1% by mass, and does not contain a carboxyl group-containing monomer as a copolymer component. Body time is optimal. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, and itaconic acid.

As the functional group-containing monomer, a hydroxyl-containing compound is preferably used, and a (meth) acrylate containing a hydroxyl group is preferably used. The acrylic copolymer (A) is preferably one obtained by copolymerizing a copolymer component having a hydroxyl group-containing (meth) acrylate content of 0.2 to 40% by mass based on the total amount of the copolymer component. When the content of the hydroxyl group-containing (meth) acrylate is within the above range, the acrylic copolymer (A) can be appropriately crosslinked by a crosslinking agent described later.

The content of the hydroxyl group-containing (meth) acrylate is preferably 1 to 30% by mass, and more preferably 5 to 30% by mass. When the (meth) acrylic acid ester containing a hydroxyl group is 1 to 30% by mass, suitable adhesive properties can be ensured, and a compound containing an unsaturated group described later can be appropriately introduced into a side chain, and acrylic acid can be further added with a crosslinking agent. The copolymer (A) is appropriately crosslinked.

As a specific example of the (meth) acrylate containing a hydroxyl group, Examples include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and the like.

The above functional group-containing monomers may be used alone or in combination of two or more.

The acrylic copolymer (A) may be an alkyl (meth) acrylate or a (meth) acrylic acid ester other than the functional group-containing monomer, or a dialkyl (meth) acrylamide in addition to the monomers described above. , Vinyl formate, vinyl acetate, styrene, vinyl acetate and the like are contained as copolymer components. As the (meth) acrylic acid ester other than the (meth) acrylic acid alkyl ester and the functional group-containing monomer, an alkoxyalkyl (meth) acrylate or an alkyloxyalkyl (meth) acrylate can be used. Esters, nonylphenoxy polyethylene glycol (meth) acrylate, tetrahydrofuran acrylate, diacrylates of polyether and acrylic esters, and the like.

Examples of the dialkyl (meth) acrylamide include dimethyl (meth) acrylamide, diethyl (meth) acrylamide, and the like. Dialkyl (meth) acrylamide is an energy ray hardening type adhesive composition, and it is preferable to use it in the X-Y type mentioned later. By using dialkyl (meth) acrylamide as a constituent monomer, the phase of an energy ray-curable acrylic copolymer of an energy ray polymerizable compound (B) such as a highly polar urethane acrylate is used. Solubility will increase.

The weight average molecular weight of the acrylic copolymer is preferably 100,000 or more, more preferably 100,000 to 1,500,000, and still more preferably 150,000 to 1,000,000. In addition, the average weight of the so-called acrylic polymer The sub-quantity is an acrylic copolymer before the reaction when a compound containing an unsaturated group described later becomes an energy ray-curable acrylic polymer through reaction.

The energy ray-curable adhesive composition is only required to have energy ray-curable properties, and is not particularly limited, and an X-type is preferred. The so-called X-type energy ray hardening adhesive composition means that the acrylic copolymer (A) itself has energy ray curability, and specifically, at least a part of the acrylic copolymer (A) has an unsaturated group in a side chain. Energy ray hardening acrylic copolymer.

The energy ray-curable acrylic copolymer is an acrylic copolymer obtained by copolymerizing the above-mentioned copolymer components and reacted with a compound containing an unsaturated group.

The unsaturated group-containing compound is a substituent having a function capable of reacting with a functional group of a functional group-containing monomer constituting the acrylic copolymer. This substituent has various kinds depending on the kind of the functional group which the functional monomer has. For example, when the functional group is a hydroxyl group or a carboxyl group, an isocyanate group or an epoxy group is preferred as the substituent. When the functional group is a carboxyl group, an isocyanate group or an epoxy group is preferred as the substituent. If the functional group is In the case of an amine group or a substituted amine group, an isocyanate group or the like is preferred as the substituent. When the functional group is an epoxy group, a carboxyl group is more preferred as the substituent, and an isocyanate group is more preferred among them. In this way, one substituent is contained in one molecule of the unsaturated group-containing compound.

In the compound containing an unsaturated group, the energy ray polymerizable carbon-carbon double bond preferably contains 1 to 5 molecules per molecule, and more preferably contains 1 ~ 2. The energy ray polymerizable carbon-carbon double bond is preferably a (meth) acrylfluorenyl group. Specific examples of such an unsaturated group-containing compound include (meth) acryloxyethyl isocyanate, methyl-isopropenyl-α, α-dimethylbenzyl isocyanate, and (methyl) Acrylic fluorenyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate, (meth) acrylic acid, and the like. In addition, there may be mentioned an acrylfluorenyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a hydroxyethyl (meth) acrylate; a diisocyanate compound or a polyisocyanate compound, a polyol compound, and Acrylic fluorenyl monoisocyanate compounds and the like obtained by the reaction of hydroxyethyl (meth) acrylate.

As the unsaturated group-containing compound, a polymerizable group-containing polyalkyleneoxy compound such as the following formula (1) can also be used.

In the formula, R ¹ is hydrogen or methyl, preferably methyl, and R ² to R ^{5 are} each independently hydrogen or an alkyl group having 1 to 4 carbons, preferably hydrogen, and n is an integer of 2 or more. It is preferably 2 to 4. The plural R ² to R ⁵ may be the same or different from each other. That is, since n is 2 or more, the polyalkyleneoxy group containing a polymerizable group represented by the above formula (1) contains two or more R ² . In this case, two or more R ² may be the same or different. The same applies to R ³ to R ⁵ . NCO represents an isocyanate group.

Compounds containing unsaturated groups In terms of 100 equivalents of the functional group of the polymer, it is usually about 10 to 100 equivalents. If it is less than the equivalents of the functional group, the crosslinking by the cross-linking agent can be appropriately performed, and it is preferable to use 15 to 95 equivalent , It is more preferable to use a ratio of about 20 to 90 equivalents.

As the unsaturated group-containing compound, a compound having a (meth) acrylfluorenyl group and an isocyanate group is preferably used, and a (meth) acrylfluorenyl ethyl isocyanate is particularly preferable.

The energy ray-curable adhesive composition may be a Y-type energy ray-curable adhesive composition. The Y-type energy ray-curable adhesive composition is different from the acrylic copolymer (A) in that it imparts energy ray curability by adding an energy ray polymerizable compound (B).

As the energy ray polymerizable compound (B), an energy ray polymerizable oligomer or energy such as epoxy acrylate type, urethane acrylate type, polyester acrylate type, polyether acrylate type can be used. Linear polymerizable monomer.

As the energy ray polymerizable monomer, a low-molecular-weight compound having at least two or more photopolymerizable carbon-carbon double bonds in a molecule, and a low molecular weight compound is used, and specifically, trimethylolpropane tri (meth) acrylate can be used , Tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (methyl) ) Acrylate or 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and the like.

Among these, it is particularly preferable to use a urethane acrylate-based oligomer. The urethane acrylate-based oligomer is a compound containing an isocyanate unit and a polyol unit and having a (meth) acrylfluorene group at a terminal. Examples of the urethane acrylate-based oligomer include a polyol having a hydroxyl group at a terminal thereof such as a polyether polyol, a polyester polyol, and the like, and reacting with a polyisocyanate to generate a terminal isocyanate urethane Ester oligomers, compounds obtained by reacting compounds having a (meth) acrylfluorenyl functional group at the terminal. In this way, the urethane acrylate-based oligomer has energy ray-hardenability by the action of a (meth) acrylfluorenyl group.

Examples of the polyisocyanate used in the urethane acrylate-based oligomer include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, and 1,3-diisocyanate. Xylene cyanate, 1,4-diisocyanate xylene, diphenylmethane 4,4-diisocyanate, isophorone diisocyanate, 1,3-bis- (isocyanatomethyl) -cyclohexyl Alkanes, 4,4'-dicyclohexylmethane diisocyanate and the like. Examples of the compound having a (meth) acrylfluorenyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and polyethylene glycol (meth) acrylate (Meth) acrylates having a hydroxyl group. Examples of the (meth) acrylic acid ester having a hydroxyl group include a partial ester of a polyhydric alcohol such as pentaerythritol and (meth) acrylic acid.

The urethane acrylate oligomer is preferably one having two or more (meth) acrylfluorene groups in one molecule and having two or more functional groups, but when not used in combination with the X type, one having three or more functional groups More preferably, it is a tetrafunctional group or more. When using more than three functional groups, energy can be easily reduced The adhesive force after the irradiation of the radiation makes the peeling performance of the surface protection film easy and good. The urethane acrylate-based oligomer is generally one having 12 or less functional groups.

In addition, the urethane acrylate-based oligomer is preferably one having a weight average molecular weight of 1,000 to 15,000, and more preferably 1500 to 8500.

The energy ray polymerizable compound (B) is usually added in an amount of 5 to 200 parts by mass to 100 parts by mass of the acrylic copolymer (A), but when not used in combination with the X type, it is preferably 40 to 200 parts by mass, and 70 to 70 parts by mass. 150 parts by mass is preferred. When the content of the energy ray polymerizable compound (B) is within the above range, not only the adhesive force of the adhesive layer before energy ray irradiation can be appropriately maintained, but also the adhesive force hardened by energy ray can be appropriately reduced.

As the energy ray-curable adhesive composition, X-type and Y-type, that is, contained in the acrylic polymer (A) and added to the energy ray polymerizable compound (B), at least a part of the acrylic copolymer (A) is An energy ray-curable acrylic copolymer having an unsaturated group in a side chain (hereinafter also referred to as an XY type) can also be used as a preferred embodiment. By using the X-Y type, it is possible to improve the breaking strength and elongation at break of the adhesive layer, and it is easy to make it easier to reduce the paste residue of the adherend when peeling the surface protection film.

When the X-Y type is used, the same energy ray-curable acrylic copolymer can be used as the X-type type.

The energy ray polymerizable compound (B) is the same as that used for the Y-form, and preferably a urethane acrylate oligomer. As the polyisocyanate at this time, isophorone can be used. Diisocyanate Esters, 1,3-bis- (isocyanatomethyl) -cyclohexane, 4,4'-dicyclohexylmethane diisocyanate and the like are preferred. In addition, as a polyol forming a polyol unit in the urethane acrylate, polypropylene glycol (PPG), polyethylene glycol (PEG), polytetramethylene glycol, polycarbonate diol, etc. are used as The number average molecular weight of these polyols is preferably from 300 to 2000, and particularly preferably from 500 to 1,000.

In addition, since the polyhydric alcohol can make the fracture stress and elongation of the adhesive layer better, it is more preferable to contain two or more kinds of polyhydric alcohol. As the polyhydric alcohol, it is particularly preferable to contain PPG and PEG. Become the best with PEG. The molar ratio of PPG to PEG is preferably 9: 1 to 1: 9, more preferably 9: 1 to 1: 4, more preferably 4: 1 to 3: 2, and 7.5: 2.5 to 6.5: 3.5. For the best.

The urethane acrylate oligomer in the X-Y type is preferably one having two (meth) acrylfluorenyl bifunctional groups in one molecule. By using a bifunctional group, not only the peelability and the adhesiveness are good, but also it is easy to improve the breaking strength and elongation at break.

The energy ray polymerizable compound (B) in the X-Y type is preferably 1 to 50 parts by mass, and more preferably 5 to 30 parts by mass for 100 parts by mass of the acrylic copolymer (A).

The adhesive layer may have a crosslinked structure which crosslinks the acrylic copolymer (A). Examples of the crosslinking agent (C) contained in the energy ray-curable adhesive composition to be crosslinked include organic polyvalent isocyanate compounds, organic polyvalent epoxy compounds, and organic polyvalent imine compounds, and the like. Organic polyvalent isocyanate compounds (isocyanate-based crosslinking agents) are also used as good.

Examples of the organic polyvalent isocyanate compound include an aromatic polyvalent isocyanate compound, an aliphatic polyvalent isocyanate compound, an alicyclic polyvalent isocyanate compound, a trimer of these organic polyvalent isocyanate compounds, and the organic polyvalent isocyanate. A terminal isocyanate urethane prepolymer and the like obtained by reacting a compound with a polyol compound.

Further specific examples of the organic polyvalent isocyanate compound include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, 1,3-diisocyanate, and 1,4-diisocyanate. Toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylidene diisocyanate, isophor Ketone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, the addition of toluene diisocyanate and trimethylolpropane.

Specific examples of the organic polyvalent epoxy compound include 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, N, N, N ', N'-tetrashrink Glyceryl-m-xylylene diamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline , Diglycidylamine, etc.

Specific examples of the organic polyvalent imine compound include N, N'-diphenylmethane-4,4'-bis (1-azacyclopropanecarboxyamidoamine), and trimethylolpropane-tri- β-aziridine propionate, tetramethylolmethane-tri-β-aziridine propionate, and N, N'-toluene-2,4-bis (1-azetidinyl carboxyfluorene Amine) triethylene melamine and the like.

The content of the cross-linking agent (C) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.5 to 8 parts by mass for 100 parts by mass of the acrylic copolymer (A). Used at the ratio. When the content of the cross-linking agent (C) is below the above-mentioned upper limit, excessive cross-linking of the adhesive layer can be prevented, and an appropriate adhesive force can be easily obtained. Moreover, when the usage-amount of a crosslinking agent is more than the said lower limit, it can prevent the adhesive agent from remaining on an electronic member or an optical member.

The energy ray-curable adhesive composition is preferably one containing a photopolymerization initiator (D).

Examples of the photopolymerization initiator include a photoinitiator such as a benzoin compound, an acetophenone compound, a fluorenylphosphine oxide compound, a titanocene compound, a thioxanthone compound, or a peroxide compound, and a photosensitizer such as an amine or a quinone. Specific examples include 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, and tetramethylthiuram monomer. Sulfides, azobisisobutyronitrile, diphenylmethyl, diethylhydrazone, β-chloroanthraquinone, 2,4,6-trimethylbenzylidene diphenylphosphine oxide, and the like. By adding a photopolymerization initiator (D), the irradiation time and amount of energy rays used for curing can be reduced.

The content of the photopolymerization initiator (D) is not particularly limited, but it is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, for 100 parts by mass of the acrylic copolymer (A).

In addition, if the light transmittance of the surface protection film is less than 50%, the adhesive layer can be colored. By coloring the adhesive layer, it can improve Since the surface protection film is distinguishable, for example, the surface protection film can be easily peeled off from a peeling sheet described later by humans. The light transmittance of the so-called surface protection film was measured at a wavelength of 600 nm using a UV-3600 spectrophotometer manufactured by Shimadzu Corporation. The light transmittance is preferably about 10 to 40%.

To color the adhesive layer, the energy ray-curable adhesive composition may generally contain dyes and pigments, and among them, blue dyes and blue pigments are also preferred.

The energy ray-curable adhesive composition may suitably contain components other than the above-mentioned components such as an anti-deterioration agent, an antistatic agent, a flame retardant, a polysiloxane, and a chain transfer agent.

The adhesive force before the energy ray irradiation of the adhesive layer is preferably 1000 to 20,000 mN / 25 mm, and more preferably 4000 to 16000 mN / 25 m. When the adhesive force before the energy ray irradiation is more than 1000mN / 25m, the adhesion force to the optical member or electronic member of the surface protection film will be high, and the protection performance will be good. Moreover, when it is 20000mN / 25mm or less, the adhesive force after irradiation with an energy ray can be easily made into a desired magnitude. The adhesive force before energy ray irradiation can be adjusted by the type and mixing ratio of the alkyl (meth) acrylate, the amount of cross-linking agent used, and the like.

In addition, the adhesive force after the energy ray irradiation of the adhesive layer is preferably 0.1 to 100 mN / 25 mm, and more preferably 20 to 90 mN / 25 mm. If the adhesive force after the energy ray irradiation is in this range, the surface protection film can be easily peeled off by the optical member or the electronic member after the energy ray irradiation.

Energy ray polymerizable compound The type or amount of (B) and the amount of unsaturated groups introduced into the acrylic copolymer are controlled.

The initial adhesive force before the energy ray irradiation of the adhesive layer is preferably less than 10,000 mN / 25 mm. When the initial adhesive force is set to this relatively low value, the adhesion of the surface protective film is easily corrected, and reworkability can be improved. The lower limit of the initial adhesive force is not particularly limited, but is usually 500 mN / 25 mm or more. The initial adhesion is preferably 3000 ~ 9500mN / 25mm.

In addition, the initial adhesive force can be adjusted by the type and mixing ratio of the alkyl (meth) acrylate, the type and mixing ratio of the functional group-containing monomer, the amount of the crosslinking agent used, and the like.

The method for measuring the adhesive force and the initial adhesive force is a value measured according to the method described in the examples.

The thickness of the adhesive layer is not particularly limited, but is preferably 3 to 50 μm, and more preferably 5 to 30 μm. When the thickness of an adhesive layer exists in the said range, it will become easy to improve the adhesiveness with respect to an adhesive body.

<Substrate>

The material of the substrate is not particularly limited. Polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, chlorinated vinyl copolymer film, Polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, vinyl acetate film, ionomer resin film, ethylene. (Meth) acrylic copolymer film, polystyrene film, Films such as polycarbonate films and fluororesin films. Moreover, these may be a crosslinked film and a laminated film.

In addition, the substrate must be transmissive to the wavelength of the energy ray used. That is, when ultraviolet rays are used as the energy ray, a light-transmitting film is used as the base material. When an electron beam is used as the energy ray, the substrate does not need to be light-transmissive, and a film to be colored can be used. In addition, the thickness of the substrate can be adjusted according to the required properties of the surface protection film, etc., preferably 10 to 300 μm, and particularly preferably 30 to 150 μm.

The film area of the surface protection film is preferably 100 mm ² or less, and more preferably about 10 to 80 mm ² . The surface protection film can be reduced in size in accordance with the optical member and the electronic member. However, if the peeling performance is desired as described above, even if the size is reduced, it can be easily peeled by manual operation. The shape of the surface protection film is not limited, and it can be processed into, for example, a circle, a ring, a square, a rectangle, or the like.

A release sheet is attached to the adhesive layer side of the surface protection film, and can be protected by the release sheet. As a release sheet, one side of a film such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, and polyethylene can be subjected to a release treatment with a release agent such as silicone resin. Etc., but it is not limited to these. In addition, a plurality of surface protection films may be provided on one release sheet having a sufficiently larger size than the surface protection film.

The method for forming the adhesive layer is not particularly limited. The energy-ray-curable adhesive composition diluted with an appropriate solvent as necessary is applied to a release sheet to a predetermined dry film thickness, and then dried to form an adhesive layer. , Formed by bonding a substrate to an adhesive layer. Also, as necessary, The diluted energy ray-curable adhesive composition is directly coated on the substrate by the solvent, and then dried to form an adhesive layer.

In addition, the surface protection film is an adhesive layer partially provided on the substrate, and an adhesive portion and a non-adhesive portion can be formed on the substrate at the same time. To create a surface protection film with a partially-adhesive layer, it is possible to form an adhesive part and a non-adhesive part by screen printing or inkjet printing. The pattern of at least one of the adhesive part and the non-adhesive part and the adhesive part is selected from a plurality of shapes arranged in a stripe shape, a lattice shape, a dot shape, a wave line shape, a plurality of arranged in a checkered pattern, and various shapes It is better to have other shapes.

Moreover, for each pattern, the interval between the patterns (that is, the interval between adjacent adhering portions or the interval between adjacent non-adhesive portions) is preferably 10 to 500 μm, more preferably 10 to 300 μm, and particularly preferably 10 ~ 250μm.

That is, the width of each stripe, the width of each wave line, and the interval between wave lines and wave lines, the width of each line that becomes a grid, and the interval between the lines and lines adjacent to the grid, the interval between points, and the point width and height, Alternatively, the height and width of each of the squares constituting the checkered pattern are preferably 10 to 500 μm, more preferably 10 to 300 μm, and particularly preferably 10 to 250 μm.

In addition, before or after the formation of the adhesive layer, press processing is possible. The pressing process may be performed on, for example, a laminate of a substrate and an adhesive layer provided on a release sheet, and the surface protection film may be formed into a circular shape as described above by the pressing process. In addition, suitable irregularities can be formed on the surface protective film by embossing or the like at any time.

[Optical or electronic components]

Examples of optical or electronic components protected by the surface protection film of the present invention include image modules in which one or more lenses and image sensors such as CCD and CMOS are housed in a frame or package; multiple lenses Lens units stored in lens barrels and stored in frames or packages as necessary; light-emitting element units with light-emitting elements such as LEDs; motor units such as vibrators; communication modules, induction modules, etc. These optical members or electronic members are preferably members connected to other members such as a substrate and used.

In addition, the so-called optical member may be an optical component that is capable of subjecting light to light or emitting light, or transmitting light. Among the aforementioned image modules, lens units, light-emitting element units, communication modules that transmit or receive optical signals, and light sensors, Modules and the like can be given as specific examples of the optical member. The electronic component generally constitutes at least a part of an electrical circuit, and includes electronic components that transmit or receive electrical signals, electronic components that process electrical signals, and electronic components that operate by electrical signals or electricity. The above-mentioned image module, light-emitting element unit, motor unit such as a vibrator, a communication module that transmits or receives electrical signals, various induction modules, and the like can be cited as specific examples of electronic components. In addition, a communication module or a light-sensing module, an image module, and a light-emitting element unit that transmit or receive optical signals may generally be electronic components or optical component components.

The optical member or the electronic member is preferably, for example, a case in which the electronic component or the optical component is housed in a package or a housing, or a support member is supported by the support member. In addition, it is preferable that a part of the electronic component or the optical component is exposed on the surface, and the surface protective film can be used to protect the exposed component, for example.

〔How to use surface protection film〕

The surface protection film of the present invention is used to adhere to a surface of an optical member or an electronic member, thereby protecting the surface. Specifically, an optical member or an electronic member with a surface protective film (hereinafter referred to as a member with a surface protective film) is processed, mounted on another member, inspected or transported, etc. The surface protective film is for these The surface of the optical or electronic component is protected in the step. In addition, at the end of these steps, the surface protection film is peeled from the optical member or the electronic member after the adhesive force is reduced by irradiation with energy rays when the surface protection is not required.

In addition, the member with a surface protective film can be heated in the above-mentioned steps of processing, installation, inspection, or transportation. The heating temperature at this time is not particularly limited, but is preferably about 60 to 200 ° C, and more preferably about 70 to 150 ° C. The adhesive layer improves its adhesive force by heating, but even if the adhesive layer of the surface protection film of the present invention improves its adhesive force by heating, it can reduce the adhesive force after being irradiated with energy rays, so it is not easy to peel off. Insufficient peeling or paste residue during surface protection film.

An optical member or an electronic member (a member with a surface protective film) bonded with a surface protection film is preferably one that is mounted on another member such as a substrate with an adhesive. In this case, the adhesive may be a thermosetting material. To harden the adhesive, the member with a surface protective film is usually heated at a temperature of 60 to 200 ° C or higher, preferably 70 to 150 ° C. After that, when surface protection is not required, after the surface protection film is irradiated with energy rays to reduce the adhesive force, the surface protection film is peeled from the optical member or the electronic member.

Further, the surface protection film is particularly suitable for a user of a surface protection film for an image module among the above-mentioned optical members or electronic members.

An image module is usually provided with a light receiving portion. The light receiving portion is a light receiving portion used when one side of the image module receives light from the outside and guides the light through the lens inside the module to the image element. The light receiving portion is a portion (for example, the center) provided on one surface of the image module, and is made of glass or transparent resin. The surface protection film preferably covers the light receiving portion and is adhered to the surface of the light receiving portion provided with the image module. The surface protection film is attached to the light receiving part and the surface of the frame or package around the light receiving part with high adhesion before the energy ray is irradiated. Therefore, the light receiving part provided on one side of the image module can be appropriately protected. In addition, since the surface protection film has a reduced adhesive force after being irradiated with energy rays, it can be easily peeled off from the image module, and it is possible to prevent generation of paste residue in the light receiving portion and the like.

In addition, as described above, the image module to which the surface protection film is bonded is preferably one that can be mounted on a heated substrate such as a heated substrate in order to harden the thermosetting adhesive.

[Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

The measurement method and evaluation method in the present invention are as follows.

[Weight average molecular weight (Mw)]

The measurement was performed under the following conditions using a gel permeation chromatography apparatus, The measured value converted from standard polystyrene was used.

(Measurement conditions)

Measuring device: Product name "HLC-8220GPC", manufactured by Tosoh Corporation)

Column: Product name "TSKGel SuperHZM-M", manufactured by Tosoh Co., Ltd.)

Development solvent: tetrahydrofuran

Column temperature: 40 ℃

Flow rate: 1.0mL / min

〔Adhesiveness〕

The adhesive sheet was cut into a 25 mm wide sample, and the silicon wafer was bonded to the bonded body with a 2 kg roller under an environment of 23 ° C and 50% relative humidity. After standing for 20 minutes in an environment of 23 ° C and 50% relative humidity, the adhesive force at the time of peeling at a tensile speed of 300 mm / min and 180 ° was measured as the adhesive force before energy ray irradiation. In addition, the sample bonded to the silicon wafer after standing for 20 minutes was irradiated with ultraviolet rays (illuminance 230 mW / cm ² , light quantity 190 mJ / cm) under a nitrogen environment using an ultraviolet irradiation device (RAD-2000m / l2 manufactured by Lintec Corporation). ² ). Thereafter, in an environment of 23 ° C and 50% relative humidity, the adhesive force at the time of peeling at a tensile speed of 300 mm / min and 180 ° was measured as the adhesive force after energy ray irradiation.

[Initial adhesion]

The adhesive sheet was cut into a 25 mm wide sample, and the silicon wafer was bonded to the bonded body with a 2 kg roller under an environment of 23 ° C and 50% relative humidity. After this lamination (within 1 minute), measure under the environment of 23 ° C and 50% relative humidity The adhesive force at the time of peeling at a tensile speed of 300 mm / min at 180 ° was used as the initial adhesive force.

〔assessment method〕

A surface protective film with a diameter of 5 mm and a film area of 19.6 mm ² was attached to the side of the light receiving part provided with the image module and evaluated according to the following evaluation criteria.

<Reworkability>

A: After the surface protection film is attached to the image module, it is easy to attach the corrected reworkability.

B: Once the surface protection film is attached to the image module, it is difficult to attach the correction and the reworkability is insufficient.

<Protective>

A: Those with good adhesion to the surface protection film of the image module are excellent.

B: There is a concern that the surface protection film of the surface protection film with a low adhesion of the surface protection film may inadvertently peel off.

<Peelability>

A: After the surface protection film attached to the image module is irradiated with ultraviolet rays, it can be easily peeled when peeled from the image module, and when visually observed, there is no paste residue in the image module.

B: After the surface protection film attached to the image module is irradiated with ultraviolet rays, when peeling from the image module, the peel resistance is high due to high peel resistance, and the time required for manual peeling is longer. Image module sees ambiguity Residual.

[Example 1]

69.5 parts by mass of n-butyl acrylate, 30 parts by mass of methacrylate, and 0.5 parts by mass of 2-hydroxyethyl acrylate were polymerized in an ethyl acetate solvent to obtain an acrylic copolymer having a weight average molecular weight of 460,000. 120 parts by mass of pentaerythritol-based 5-9 functional urethane acrylate-based oligomer having a weight average molecular weight of 2300 was mixed with 100 parts by mass of the acrylic copolymer (solid content conversion) diluted with the ethyl acetate solvent. 2.0 mass parts of IRGACURE184 (manufactured by BASF) as a photopolymerization initiator, and 8 mass parts of an organic polyvalent isocyanate compound (product name "BHS8515", manufactured by Toyokemu Co., Ltd.) as a cross-linking agent, energy ray hardening was obtained A dilute solution of ethyl acetate with an adhesive composition (type Y). The diluted solution was applied to a substrate made of a polyethylene terephthalate film having a thickness of 50 μm to a thickness of 20 μm after drying, and then heated and dried at 100 ° C. for 1 minute on the substrate. A surface protective film is obtained after forming the adhesive layer.

[Example 2]

52 parts by mass of n-butyl acrylate, 20 parts by mass of methmethacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate were polymerized in an ethyl acetate solvent to obtain an acrylic copolymer having a weight average molecular weight of 500,000. In 100 parts by mass of acrylic copolymer, methacryloxyethyl isocyanate (MOI) containing 33.7 mass of unsaturated compound is reacted. Parts by weight (90 equivalents for 100 equivalents of 2-hydroxyethyl acrylate) to obtain an ethyl acetate dilution solution of the energy ray-curable acrylic copolymer. Next, 3.3 parts by mass of IRGACURE 184 (manufactured by BASF) as a photopolymerization initiator was mixed with 100 parts by mass (solid content conversion) of the energy ray-curable acrylic copolymer diluted with ethyl acetate, and used as a crosslinking agent. 0.5 parts by mass of an organic polyvalent isocyanate compound (product name "BHS8515", Toyokemu Co., Ltd.), to obtain a dilute solution of an energy ray-curable adhesive composition (type X). Thereafter, an adhesive layer was formed on the substrate in the same manner as in Example 1 to obtain a surface protective film.

[Example 3]

The difunctional urethane acrylate-based oligomer having a weight average molecular weight of 5,500 was further diluted in the dilute solution of the energy ray-curable adhesive composition of Example 2, and the energy ray-curable acrylic copolymer was removed. The addition of 100 parts by mass to 10 parts by mass was carried out in the same manner as in Example 2 (XY type). In addition, as the bifunctional urethane acrylate-based oligomer, 3 parts by mass of polymerized isophorone diisocyanate, 1.4 parts by mass of polypropylene glycol, and 0.6 parts by mass of polyethylene glycol were used. Those who react with 2 parts by mass of hydroxypropyl acrylate.

[Comparative Example 1]

90 parts by mass of n-butyl acrylate and 10 parts by mass of acrylic acid were polymerized in an ethyl acetate solvent to obtain a weight average molecular weight of 550,000. Acrylic copolymer. In 100 parts by mass (in terms of solid content) of the acrylic copolymer diluted with this ethyl acetate, 120 parts by mass of a 5 to 9 functional urethane acrylate oligomer having a weight average molecular weight of 2,300 was mixed as the photocatalyst. A polymerization initiator containing 2.0 parts by mass of IRGACURE184 (manufactured by BASF) and 17 parts by mass of an organic polyvalent isocyanate compound (product name "BHS8515", manufactured by Toyokemu Co., Ltd.) as a cross-linking agent were used as energy The step of diluting the linear curing adhesive composition (Y type) was carried out in the same manner as in Example 1.

[Comparative Example 2]

90 parts by mass of n-butyl acrylate and 10 parts by mass of acrylic acid were polymerized in an ethyl acetate solvent to obtain an acrylic copolymer having a weight average molecular weight of 550,000. 100 parts by mass of the ethyl acetate-diluted acrylic copolymer (in terms of solid content) and 120 parts by mass of a 3 to 4-functional urethane acrylate oligomer having a weight average molecular weight of 8,000 were mixed as photopolymerization. 2.0 parts by mass of IRGACURE184 (manufactured by BASF) as an initiator and 11 parts by mass of an organic polyvalent isocyanate compound (product name "BHS8515", manufactured by Toyokemu Co., Ltd.) as a crosslinking agent, except for use as an energy ray hardening adhesive The step of diluting the composition (Y type) was carried out in the same manner as in Example 1.

[Comparative Example 3]

A weight average was obtained by polymerizing 80 parts by mass of 2-ethylhexyl acrylate and 20 parts by mass of 2-hydroxyethyl acrylate in an ethyl acetate solvent. An acrylic copolymer having a molecular weight of 470,000 is further added to 100 parts by mass of the acrylic copolymer (in terms of solid content) and 21 parts by mass of methacryloxyethyl isocyanate (MOI) of the unsaturated group-containing compound (for 2- 100 equivalents of hydroxyethyl acrylate were reacted) to obtain an energy ray-curable acrylic copolymer. 100 parts by mass of the energy ray-curable acrylic copolymer (solid content conversion) used for diluting with this ethyl acetate was removed, and 2.0 parts by mass of IRGACURE184 (manufactured by BASF) as a photopolymerization initiator was mixed and used as a crosslinking agent An energy ray-curable adhesive composition (type X) obtained by diluting 1 part by mass of an organic polyvalent isocyanate compound (product name "BHS8515", manufactured by Toyokemu Co., Ltd.) was implemented in the same manner as in Example 1.

[Comparative Example 4]

85 parts by mass of butyl acrylate, 9 parts by mass of methacrylate, 5 parts by mass of hydroxyacrylate, and 1 part by mass of acrylic acid were polymerized in an ethyl acetate solvent to obtain an acrylic copolymer having a weight average molecular weight of 460,000. Thing. 8 parts by mass of an organic polyvalent isocyanate compound (product name "BHS8515", manufactured by Toyokemu Co., Ltd.) as a crosslinking agent was mixed with 100 parts by mass of the acrylic copolymer (solid content conversion) diluted with the ethyl acetate solvent. Parts to obtain a diluent of the non-energy ray-curable adhesive composition. This diluent of the non-energy-ray-curable adhesive composition was used in the same manner as in Example 1 except that the diluent of the energy-ray-curable adhesive composition was used instead.

In the above Examples 1 to 3, the acrylic copolymer was an alkyl (meth) acrylate having a carbon number of 1 or 2 as the amount of the alkyl group as a copolymer component. Monomer, so the adhesion and initial adhesion before UV irradiation are good values, and a surface protective film with excellent reworkability and protection can be obtained. In addition, since the adhesive force becomes low after UV irradiation, the peeling performance is also good.

On the other hand, in Comparative Examples 1 to 3, the acrylic copolymer did not contain an alkyl (meth) acrylate having a carbon number of 1 or 2 as a specified amount of the alkyl group as a copolymer component, or contained The carboxyl monomer is 5 mass% or more, so the adhesive force after UV irradiation is not sufficiently reduced, and the peeling performance is not good. Moreover, in Comparative Example 2, it was not the case where the initial adhesion was also high and the reworkability was also good. Moreover, in Comparative Example 4, since a non-energy ray hardening type was used, it was difficult to be a person with good protective properties and peelability.

Claims (11)

A surface protection film, which is used for protecting an optical member or an electronic member and is used for protecting the surface, is characterized by having a substrate, and an adhesive layer provided on one side of the substrate. The aforementioned adhesive layer is composed of It is made of an energy ray hardening adhesive composition containing an acrylic copolymer (A). The acrylic copolymer (A) is an alkane having a carbon number of 1 or 2 which copolymerizes at least 5 to 50% by mass of an alkyl group. (Meth) acrylic acid ester, a monomer component containing no carboxyl group-containing monomer or a monomer component containing less than 5% by mass of the carboxyl group-containing monomer, wherein the aforementioned energy ray-curable adhesive composition is further An energy ray polymerizable compound (B) is contained, the energy ray polymerizable compound (B) is a urethane acrylate oligomer, and the weight average molecular weight of the urethane acrylate oligomer is 1000 ~ 15000. The surface protective film according to claim 1, wherein the acrylic copolymer (A) is an energy ray-curable acrylic copolymer having an unsaturated group in a side chain. For example, the surface protection film of claim 1 or 2, wherein the aforementioned acrylic copolymer (A) is a unit of further copolymerizing an alkyl (meth) acrylate containing 30 to 85% by mass of an alkyl group having a carbon number of 3 or more Body composition income. For example, the surface protection film of claim 3, wherein the alkyl (meth) acrylate having an alkyl group having a carbon number of 3 or more is an alkyl (meth) acrylate having an alkyl group having a carbon number of 3 to 8. The surface protection film according to claim 1 or 2, wherein the acrylic copolymer (A) is obtained by further copolymerizing a monomer component containing a hydroxyl group-containing (meth) acrylate in an amount of 0.2 to 40 parts by mass. For example, the surface protection film of item 1 or 2 in which the adhesive force before the energy ray irradiation is 1000 ~ 20,000mN / 25mm, and the adhesive force after the energy ray irradiation is 0.1 ~ 100mN / 25mm. For example, the surface protection film of claim 1 or 2, in which the initial adhesive force before energy ray irradiation is less than 10000mN / 25mm. For example, the surface protection film of claim 1 or 2, wherein the aforementioned adhesive layer is colored so that the light transmittance of the surface protection film becomes less than 50%. If the surface protection film of claim 1 or 2 is attached to the image module, it is used to protect the light receiving part of the image module. A member with a surface protection film, comprising any member selected from an optical member or an electronic member, and a surface protection film according to any one of claims 1 to 9 attached to the surface of the member. A method for protecting a surface, which is characterized in that a surface protection film according to any one of claims 1 to 9 is attached to a surface of an optical member or an electronic member to protect the surface.