TWI759411B - Adhesive composition, adhesive layer, surface protection film, and optical member - Google Patents

Abstract

The present invention provides an adhesive composition, an adhesive layer obtained by crosslinking the adhesive composition, a surface protective film obtained by forming the adhesive layer on a support, and an optical member protected by the surface protective film, the adhesive The pot life of the adhesive composition is long enough, the crosslinking property (degree of crosslinking) of the adhesive composition immediately after the curing treatment and after the aging treatment is high, the color change of the adhesive layer is small, and the adhesive layer can be prevented from sticking after storage. adhesive force increased. The adhesive composition of the present invention is characterized in that, with respect to 100 parts by mass of the polymer (A) having an active hydrogen functional group, the adhesive composition contains an isocyanate-based crosslinking agent (B) in an amount of 0.001 parts by mass to 0.4 parts by mass. 0.001 to 0.4 parts by mass of the compound (C) containing tin as an active center, and 0.001 to 0.4 parts by mass of the compound (D) containing iron as an active center.

Description

Adhesive composition, adhesive layer, surface protective film, and optical member

FIELD OF THE INVENTION The present invention relates to an adhesive composition, an adhesive layer, a surface protective film, and an optical member. More specifically, it relates to an adhesive composition having a sufficiently long pot life and high crosslinkability (degree of crosslinking) immediately after curing treatment and after aging treatment, and an adhesive composition capable of suppressing changes in color tone and preventing an increase in adhesive strength after sticking and storage. An adhesive layer, and a surface protection film obtained by forming the above-mentioned adhesive layer on a support. In particular, it is useful as a surface protection film used for the purpose of protecting the surface of optical members (for example, polarizing plates, wave plates, retardation plates, optical compensation films, reflection sheets, brightness enhancement films used in liquid crystal displays, etc.) of.

Background of the Invention In recent years, adhesive sheets have been used in various aspects such as fixation (bonding), transportation, protection, and decoration of adherends. As a typical example of the said adhesive sheet, the adhesive sheet which has the adhesive bond layer formed using the acrylic adhesive composition which uses an acrylic polymer as a base polymer is mentioned. As the acrylic polymer, a copolymer containing an alkyl (meth)acrylate as a main component and a monomer containing an appropriate functional group is usually used. As an acrylic polymer having a functional group, an acrylic polymer obtained by copolymerizing a monomer component having a functional group such as a hydroxyl group is widely known, and an isocyanate compound or the like is blended as a crosslinking agent that reacts with the functional group to obtain an adhesive combination. The acrylic polymer is cross-linked, thereby forming an adhesive layer.

Incidentally, in the crosslinking reaction of an acrylic polymer having a hydroxyl group or the like and an isocyanate compound, a metal catalyst such as a tin compound such as dibutyltin dilaurate is generally used (see Patent Document 1).

In addition, the adhesive composition used for forming the adhesive layer may be kept as it is for a certain period of time according to the production plan, and crosslinking may be performed at this stage. When the crosslinking is performed at the stage of the adhesive composition, the viscosity of the adhesive composition increases or insoluble matter is generated, which causes surface roughness and thickness variation of the adhesive layer in the subsequent formation of the adhesive layer. In addition, it sometimes affects the adhesive properties. Therefore, an adhesive composition that does not undergo crosslinking at the stage of the adhesive composition, has a so-called pot life that is sufficiently long, and is rapidly crosslinked when an adhesive layer is formed is desired.

However, for an adhesive layer using a metal catalyst such as a tin compound, it is difficult to obtain a high crosslinkability (degree of crosslinking) immediately after curing treatment (heat treatment) or to obtain an adhesive combination having a sufficiently long pot life thing.

In addition, an attempt has been made to use a metal catalyst such as a compound containing an iron atom as a crosslinking catalyst in place of the tin compound (see Patent Document 2).

An adhesive layer obtained by using a compound containing an iron atom as a metal catalyst can obtain a high crosslinkability (degree of crosslinking) immediately after curing treatment (heat treatment), but on the other hand, it is difficult to obtain a high degree of crosslinking during aging treatment. Crosslinkability (degree of crosslinking) or difficulty in suppressing coloration of the adhesive layer due to coloration by the iron atom-containing compound (coloration based on the metal complex in the iron atom-containing compound). Prior Art Documents Patent Documents

Patent Document 1: Japanese Patent Laid-Open No. 2005-314513 Patent Document 2: Japanese Patent Laid-Open No. 2011-1440

SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION Therefore, in the present invention, in view of the above-mentioned circumstances, intensive research was conducted, and as a result, an object of the present invention is to use an isocyanate-based crosslinking agent (B) to provide a base polymer with reactive The hydrogen-functional polymer (A) cross-linked adhesive composition is used in combination as a cross-linking catalyst with a specific ratio of a compound (C) with an active center of tin and a compound (D) with an active center of iron to provide a binder. The pot life of the composition is sufficiently long, the crosslinkability (degree of crosslinking) immediately after the curing treatment (heat treatment) of the adhesive composition and after the aging treatment is high, and the occurrence of the compound (D) having iron as an active center can be suppressed. An adhesive composition capable of preventing a change in color tone of the adhesive layer (based on the coloring of the metal complex in the iron atom-containing compound) and preventing the adhesive force from increasing after the adhesive layer is adhered and stored, and the adhesive composition An adhesive layer obtained by crosslinking, a surface protective film obtained by forming an adhesive layer on a support, and an optical member protected by the surface protective film. means of solving problems

That is, the adhesive composition of the present invention is characterized in that the adhesive composition contains the isocyanate-based crosslinking agent (B), 0.001 parts by mass to 100 parts by mass of the polymer (A) having an active hydrogen functional group 0.4 parts by mass of compound (C) having tin as an active center, and 0.001 to 0.4 parts by mass of compound (D) having iron as active center.

In the adhesive composition of the present invention, preferably, the above-mentioned active hydrogen-containing functional group is a hydroxyl group and/or a carboxyl group.

The adhesive composition of the present invention preferably contains the crosslinking agent (B) in an amount of 0.1 to 20 parts by mass relative to 100 parts by mass of the polymer (A).

In the adhesive composition of the present invention, the polymer (A) preferably contains at least one selected from the group consisting of an acrylic polymer, a polyurethane-based polymer, and a polysiloxane-based polymer.

The adhesive layer of the present invention is preferably obtained by crosslinking the above-mentioned adhesive composition.

The surface protective film of the present invention is preferably obtained by forming the above-mentioned adhesive layer on at least one surface of the support.

The optical member of the present invention is preferably protected by the above-mentioned surface protection film. Invention effect

The adhesive composition of the present invention does not undergo a cross-linking reaction at the stage of the adhesive composition, can obtain a sufficiently long pot life, can be stored for a certain period of time, and can formulate a production plan with a surplus. In addition, after the adhesive layer is formed, the crosslinking proceeds rapidly, the crosslinkability (degree of crosslinking) is high, the crosslinking stability is excellent, and the surface protection of the adhesive layer-containing layer during production or storage can be prevented. The effects of deformation and damage caused by the external pressure of the film. In addition, it is possible to suppress the color change of the adhesive layer (coloration by the metal complex in the iron atom-containing compound) caused by the compound (D) containing iron as an active center, which can be used for optical applications, and can prevent the adhesive Since the adhesive force after the sticking and storage of the layer increases, it is excellent in re-peelability, which is useful.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. <Overall structure of surface protection film>

The surface protection film disclosed herein is generally called an adhesive sheet, an adhesive tape, an adhesive label, an adhesive film, or the like, and is particularly suitable for use as a liquid crystal display panel in an optical member (for example, a polarizer, a wave plate, etc.) A surface protection film that protects the surface of the optical member at the time of processing and transportation of the optical member constituting the element and the optical member used in the touch panel display such as the hard coat film. The adhesive layer in the above-mentioned surface protection film is typically formed continuously, but is not limited to this form, and may be, for example, an adhesive layer formed in a regular or random pattern such as dots and stripes. In addition, the surface protective film disclosed here may be in a roll shape or a paper shape (leaf shape). ＜Adhesive composition＞

The adhesive composition of the present invention is characterized in that, with respect to 100 parts by mass of the polymer (A) having an active hydrogen functional group, the adhesive composition contains an isocyanate-based crosslinking agent (B) in an amount of 0.001 parts by mass to 0.4 parts by mass. 0.001 to 0.4 parts by mass of the compound (C) containing tin as an active center, and 0.001 to 0.4 parts by mass of the compound (D) containing iron as an active center. By using a specific ratio of the compound (C) with tin as the active center (hereinafter sometimes referred to as "tin catalyst (C)") and the compound (D) with iron as the active center (hereinafter sometimes referred to as "iron catalyst") (D)") as a cross-linking catalyst, the pot life of the adhesive composition is sufficiently long, the cross-linkability (degree of cross-linking) of the adhesive composition immediately after the curing treatment and after the aging treatment is high, and iron can be suppressed The color change of the adhesive layer caused by the catalyst (D) (coloration by the metal complex in the iron catalyst (D)) can be suppressed, and the color change of the adhesive layer can be suppressed, and the adhesion of the adhesive layer can be prevented. Adhesive compositions with increased adhesive force are therefore preferred. (Polymer (A) having active hydrogen-containing functional group)

The adhesive composition of the present invention is characterized by containing a polymer (A) having an active hydrogen-containing functional group, and preferably, the active hydrogen-containing functional group of the polymer (A) is a hydroxyl group and/or a carboxyl group. The active hydrogen-containing functional group of the above-mentioned polymer (A) can react with the isocyanate-based crosslinking agent (B) described later, and the polymer having the above-mentioned active hydrogen-containing functional group on the main chain or side chain can react with the isocyanate-based crosslinking agent. It is preferable because the reaction proceeds efficiently.

Moreover, in the adhesive composition of this invention, it is preferable that the said polymer (A) contains at least 1 sort(s) chosen from the group which consists of an acrylic polymer, a urethane type polymer, and a polysiloxane type polymer. Among them, the above-mentioned polymer (A) is more preferably an acrylic polymer having an active hydrogen-containing functional group from the viewpoint of the degree of freedom of adhesive design.

The acrylic polymer having an active hydrogen-containing functional group is an acrylic polymer having an active hydrogen-containing functional group, such as a hydroxyl group and a carboxyl group, which can react with the isocyanate-based crosslinking agent (B) described later, in the main chain or side chain. Such an acrylic polymer having an active hydrogen-containing functional group may contain at least an alkyl (meth)acrylate as a main component and an active hydrogen-containing functional group monomer (hereinafter, sometimes referred to as an "active hydrogen functional group-containing monomer"). ) as a monomer component and obtained by copolymerization thereof.

In the present invention, the alkyl (meth)acrylate as the main monomer constituting the acrylic polymer having an active hydrogen functional group is preferably an alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms base ester. Specific examples thereof include, for example, butyl (meth)acrylate, isobutyl (meth)acrylate, 3rd butyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate Amyl acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylate 2-ethylhexyl acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecane (meth)acrylate base ester, dodecyl (meth)acrylate, etc.

These alkyl (meth)acrylates having an alkyl group having 4 to 12 carbon atoms may be used alone or in combination, and the overall content ratio is preferably 70% by mass to 99.9% in the monomer components % by mass, more preferably 80% by mass to 99.5% by mass, and still more preferably 85% by mass to 99% by mass. When the content ratio of the above-mentioned alkyl (meth)acrylate is less than 70% by mass, the content of the functional group-containing monomer described later or other monomers increases, the glass transition temperature of the acrylic polymer increases, and the fluidity decreases. A sufficient bonding area cannot be obtained to fix the adherend. In addition, it may be difficult to adjust the degree of crosslinking (the amount of gel). On the other hand, when content of the said alkyl (meth)acrylate exceeds 99.9 mass %, since the content rate of a functional group containing monomer falls, crosslinking formation becomes insufficient, and the cohesion force of an adhesive composition may not be acquired.

As the active hydrogen functional group-containing monomer, an active hydrogen functional group-containing monomer having an active hydrogen-containing functional group, such as a hydroxyl group and a carboxyl group, which can react with a crosslinking agent such as an isocyanate compound, is used. Specific examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. -Hydroxybutyl, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, ( Hydroxyl-containing monomers such as hydroxyalkyl (meth)acrylates such as 12-hydroxylauryl meth)acrylate and [4-(hydroxymethyl)cyclohexyl]methyl acrylate.

In addition, as other active hydrogen functional group-containing monomers, carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, β-carboxyethyl acrylate, etc.; N-methylol acrylamide , N-Methylolmethacrylamide, N-(2-hydroxyethyl)acrylamide, N-(2-hydroxyethyl)methacrylamide, N-(2-hydroxypropyl)propene Amide, N-(2-Hydroxypropyl) Methacrylamide, N-(1-Hydroxypropyl) Acrylamide, N-(1-Hydroxypropyl) Methacrylamide, N-(3 -Hydroxypropyl) acrylamide, N-(3-hydroxypropyl) methacrylamide, N-(2-hydroxybutyl) acrylamide, N-(2-hydroxybutyl) methacrylamide Amine, N-(3-hydroxybutyl)acrylamide, N-(3-hydroxybutyl)methacrylamide, N-(4-hydroxybutyl)acrylamide, N-(4-hydroxybutyl) group) methacrylamides etc. N-hydroxyalkyl (meth)acrylamides etc.

These active hydrogen functional group-containing monomers may be used alone or in combination, and the overall content ratio in the monomer component is preferably 0.1% by mass to 30% by mass, more preferably 0.5% by mass to 20% by mass, and still more Preferably it is 1 mass % - 15 mass %. When the content of the active hydrogen functional group-containing monomer is less than 0.1% by mass, the formation of crosslinks is insufficient, the cohesion of the adhesive composition cannot be obtained, and the surface protective film may be biased when the adherend (for example, an optical member) is fixed. migration, or glue residue occurs when the surface protection film is peeled off. On the other hand, when the content ratio of the active hydrogen functional group-containing monomer exceeds 30% by mass, the cohesive force of the acrylic polymer increases, so the fluidity decreases, and a sufficient adhesion area may not be obtained and the adherend may not be fixed. .

In the present invention, monomers other than the above-mentioned alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms and active hydrogen functional group-containing monomers can be used as monomer components. Examples of such other monomers include (meth)acrylic acid alkyl esters having an alkyl group other than 4 to 12 carbon atoms. As a specific example of the alkyl (meth)acrylate which has an alkyl group other than C4-C12 used for this invention, methyl (meth)acrylate, (methyl) Ethyl acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate Alkyl ester, cetyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, (meth)acrylate base) eicosyl acrylate, etc.

In addition, as other monomers that can be used in the present invention, cyclic (meth)acrylamides such as N-(meth)acrylomorpholine and N-acrylopyrrolidine; ) acrylamide, N-substituted (meth) acrylamide (for example, N-alkyl (methyl) ) acrylamide; N,N-dimethyl (meth) acrylamide, N,N-diethyl (meth) acrylamide, N,N-dipropyl (meth) acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-di-n-butyl(meth)acrylamide, N,N-di-3-butyl(meth)acrylamide, etc. N , N-dialkyl (meth) acrylamide and other acyclic (meth) acrylamide; N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl- 3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholindione, etc. N- Vinyl cyclic amide; (meth)acrylate aminoethyl ester, (meth)acrylate N,N-dimethylaminoethyl ester, (meth)acrylate N,N-dimethylaminopropyl ester Monomers with amine groups such as N-cyclohexylmaleimide, N-phenylmaleimide and other monomers with maleimide skeleton; N-methylitaconimide, N -Ethyl itaconimide, N-butyl itaconimide, N-2-ethylhexyl itaconimide, N-lauryl itaconimide, N-cyclohexyl itaconimide Amines and other itaconic imide monomers; etc. nitrogen atom-containing monomers, etc.

Other examples of monomers that can be used as other monomers include monomers having epoxy groups such as glycidyl (meth)acrylate and allyl glycidyl ether; methoxy (meth)acrylate Monomers with alkoxy groups such as methyl ethyl ester, methoxypropyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; acrylonitrile 2- Monomers with isocyanate groups such as methacryloyloxyethyl isocyanate; Vinyl ester monomers such as vinyl acetate and vinyl propionate; Vinyl ether monomers such as vinyl ether; (meth)acrylic acid tetrakis Heterocyclic (meth)acrylates such as hydrofurfuryl; monomers with halogen atoms such as fluoro(meth)acrylates; 3-methacryloyloxypropyltrimethoxysilane, vinyltrimethoxysilane Monomers with alkoxysilyl groups such as siloxane; Monomers with siloxane bonds such as polysiloxane (meth)acrylates; Cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate (meth)acrylates having alicyclic hydrocarbon groups, such as esters, bornyl (meth)acrylate, isobornyl (meth)acrylate, etc.; phenyl (meth)acrylate, benzyl (meth)acrylate, (meth)acrylate (meth)acrylate having an aromatic hydrocarbon group, such as phenoxyethyl acrylate, phenoxydiethylene glycol (meth)acrylate, etc.; and the like.

In addition, as other monomers, for example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate can be used. (Meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate Esters, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester Acrylate, urethane acrylate, divinylbenzene, butyl di(meth)acrylate, hexyl di(meth)acrylate and other multifunctional monomers.

These other monomers may be used alone or in combination, and the overall content of the monomer components is preferably 29.9 mass % or less, more preferably 19.5 mass % or less, and still more preferably 14 mass % or less. When the content ratio of other monomers exceeds 29.9% by mass, the content of the alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms decreases, the glass transition temperature of the acrylic polymer increases, and the fluidity increases. If it falls, a sufficient bonding area may not be obtained and the adherend may not be fixed.

For the acrylic polymer used in the present invention, the preferred weight average molecular weight (Mw) is 100,000 to 3,000,000, more preferably 200,000 to 2,000,000, and still more preferably 300,000 to 1,500,000. When the weight average molecular weight (Mw) is less than 100,000, the cohesive force of the adhesive layer tends to decrease, and the surface protective film may be displaced when the adherend (for example, an optical member) is fixed, or the surface protective film may be peeled off. A glue residue is produced. On the other hand, when the weight-average molecular weight (Mw) exceeds 3 million, the cohesive force tends to increase due to the effect of entanglement of the polymer, and the fluidity tends to decrease, and a sufficient adhesion area may not be obtained, and the adhesion may not be performed. fixation of things. In the present invention, the weight average molecular weight (Mw) of the acrylic polymer refers to a value in terms of standard polystyrene measured by GPC (gel permeation chromatography).

The acrylic polymer used in the present invention preferably has a glass transition temperature (Tg) of 0°C or lower (usually -100°C or higher), more preferably -10°C or lower, and even more preferably -20°C or lower. When the glass transition temperature is higher than 0°C, the cohesive force increases and the fluidity decreases, and a sufficient adhesion area may not be obtained, and the adherend may not be fixed. In addition, the glass transition temperature of an acrylic polymer can be adjusted to the said range by suitably changing the monomer component and composition ratio used. As the glass transition temperature of the acrylic polymer in the present invention, a measurement method using a dynamic viscoelasticity apparatus, a calculated value obtained from the FOX equation, and the like can be used.

The polymerization method of the acrylic polymer used in the present invention is not particularly limited, and the polymerization can be carried out by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. In addition, the obtained copolymer may be any of a random copolymer, a block copolymer, and the like.

The urethane-based polymer having an active hydrogen-containing functional group is a urethane-based polymer having an active hydrogen-containing functional group such as a hydroxyl group and a carboxyl group that can react with the isocyanate-based crosslinking agent (B) described later in the main chain or side chain. As said urethane type polymer, the thing containing the urethane resin (polyurethane type polymer) obtained by making a polyol and a polyisocyanate compound react is mentioned preferably.

The above-mentioned polysiloxane-based polymer having an active hydrogen-containing functional group is a polysiloxane having an active hydrogen-containing functional group such as a hydroxyl group and a carboxyl group that can react with the isocyanate-based crosslinking agent (B) described later in the main chain or side chain. Alkane polymers. As said polysiloxane type polymer, the thing obtained by blending or agglomerating polysiloxane resin (polysiloxane type polymer, polysiloxane component) is mentioned preferably. (Isocyanate-based crosslinking agent (B))

The adhesive composition of the present invention is characterized by containing an isocyanate-based crosslinking agent (B). Examples of the crosslinking agent (B) include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), and dimer acid diisocyanate; Alicyclic isocyanates such as amyl diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane; 2,4-toluene diisocyanate Aromatic isocyanates such as isocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate (XDI); using allophanate bond, biuret bond, isocyanurate bond, A modified polyisocyanate obtained by modifying the above-mentioned isocyanate compound, such as a uretdione bond, a urea bond, a carbodiimide bond, a uretonimine bond, and an oxadiazinetrione bond. For example, commercially available products include Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (the above are manufactured by Mitsui Chemicals Co., Ltd.), Sumidule T80, Sumidule L, Desmodur N3400 (the above, Sumika Bayer Polyurethane (Sumika Bayer Polyurethane) Bayer Urethane), Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (the above are manufactured by Tosoh Corporation of Japan), etc. These isocyanate compounds may be used alone or in combination of two or more, and a difunctional isocyanate compound and a trifunctional or more isocyanate compound may be used in combination. By using a crosslinking agent in combination, both adhesiveness and resilience resistance (adhesion to a curved surface) can be achieved, and an adhesive sheet with more excellent adhesive reliability can be obtained.

In addition, when the above-mentioned isocyanate compounds (difunctional isocyanate compounds and trifunctional or higher isocyanate compounds) are used in combination, the compounding ratio (mass ratio) of the two compounds is preferably [difunctional isocyanate compound]/[ The trifunctional or higher isocyanate compound] (mass ratio) is blended in a range of 0.1/99.9 to 50/50, more preferably 0.1/99.9 to 20/80, still more preferably 0.1/99.9 to 10/90, still more preferably 0.1/99.9~5/95, the best is 0.1/99.9~1/99. It is a preferable aspect to obtain an adhesive layer excellent in adhesiveness and resilience resistance by adjusting and mixing within the above-mentioned range.

In the present invention, the content of the crosslinking agent (B) is preferably 0.1 parts by mass to 20 parts by mass, more preferably 1 part by mass to 10 parts by mass, and still more preferably based on 100 parts by mass of the polymer (A). Preferably it is 2 mass parts - 8 mass parts. When the content of the above-mentioned crosslinking agent (B) is less than 0.1 part by mass, the crosslinking formation is insufficient, the cohesion of the adhesive layer cannot be obtained, the surface protective film may be displaced when the adherend is fixed, or the surface protective film may be peeled off Glue residues are produced. On the other hand, when content of the said crosslinking agent (B) exceeds 20 mass parts, crosslinking progresses excessively and cohesion increases, fluidity falls, and a sufficient adhesion area may not be obtained, and it may not be able to fix a to-be-adhered body.

In addition to the said isocyanate type crosslinking agent (B), other crosslinking agents may be contained in the adhesive composition of this invention as needed. As another crosslinking agent, an epoxy-type crosslinking agent, a melamine-type resin, an aziridine derivative, a metal chelate compound, etc. can be used, for example. These compounds may be used alone or in combination.

As the epoxy-based crosslinking agent, for example, N,N,N',N'-tetraglycidyl m-xylylenediamine (trade name TETRAD-X, manufactured by Mitsubishi Gas Chemical Co., Ltd.), 1, 3-bis(N,N-diglycidylaminomethyl)cyclohexane (trade name TETRAD-C, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and the like. These compounds may be used alone or in combination.

As said melamine type-resin, hexamethylol melamine etc. are mentioned. Examples of the above-mentioned aziridine derivatives include commercially available trade names HDU (manufactured by Mutual Pharmaceutical Co., Ltd.), trade names TAZM (manufactured by Mutual Pharmaceutical Co., Ltd.), and trade names TAZO (manufactured by Mutual Pharmaceutical Co., Ltd.) )Wait. These compounds may be used alone or in combination.

As the metal chelate compound, aluminum, titanium, nickel, zirconium, etc. are mentioned as the metal component, and acetylene, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, acetone acetone, etc. are mentioned as the chelate compound. material composition. These compounds may be used alone or in combination.

When these cross-linking agents other than the above-mentioned cross-linking agent (B) are used in combination, the usage amount thereof is not particularly limited as long as the effect of the present invention is not impaired. The total amount of the linking agent (B) is preferably 0.1 parts by mass to 20 parts by mass, more preferably 1 part by mass to 10 parts by mass, and still more preferably 2 parts by mass to 8 parts by mass. (Compound (C) with tin as active center)

The adhesive composition of the present invention is characterized in that, with respect to 100 parts by mass of the polymer (A) having an active hydrogen functional group, the adhesive composition contains 0.001 part by mass to 0.4 part by mass of a compound having tin as an active center (C). By blending the compound (C) having tin as an active center (tin catalyst (C)), the color change of the adhesive layer can be suppressed compared with the case where only the iron catalyst (D) described later is used, and the sticking can be suppressed. The adhesive strength after storage is improved, and the re-peelability is excellent, which is a preferable form. Examples of the tin catalyst (C) include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, and diacetic acid. Dibutyltin, dibutyltin sulfide, tributylmethoxytin, tributyltin acetate, triethylethoxytin, tributylethoxytin, dioctyltin oxide, dioctyltin dilaurate, tributyltin Butyl tin chloride, tributyl tin trichloroacetate, tin 2-ethylhexanoate, etc. These tin catalysts (C) may be used alone or in combination.

With respect to 100 parts by mass of the polymer (A), the binder composition contains the tin catalyst (C) in an amount of 0.001 part by mass to 0.4 part by mass, preferably 0.002 part by mass to 0.3 part by mass, more preferably 0.003 part by mass ~0.2 part by mass, more preferably 0.004 part by mass to 0.1 part by mass. When content of the said tin catalyst (C) is less than 0.001 mass part, the crosslinking property (crosslinking degree) after an aging process may become inadequate. On the other hand, when it exceeds 0.4 parts by mass, it is difficult to suppress the increase in the viscosity of the adhesive composition (mixed solution) during storage, and the pot life of the adhesive composition may not be sufficiently obtained. Deterioration of stability over time. (Compound (D) with iron as active center)

The adhesive composition of the present invention is characterized in that, with respect to 100 parts by mass of the polymer (A) having an active hydrogen functional group, the adhesive composition contains 0.001 parts by mass to 0.4 parts by mass of a compound having iron as an active center (D). By compounding the above-mentioned compound (D) containing iron as an active center (iron catalyst (D)), unlike the case of using only the tin catalyst (C), it is possible to obtain a high crosslinkability (degree of crosslinking) immediately after curing treatment. And an adhesive composition with a long enough pot life is a better way. As said iron catalyst (D), an iron chelate compound can be used suitably, For example, it can be represented by general formula Fe(X)(Y)(Z). Fe(X)3, Fe(X)2(Y), Fe(X)(Y)2, Fe(X)(Y) Any one of (Z) represents. In the iron chelate compound Fe(X)(Y)(Z), (X)(Y)(Z) is a ligand for Fe, for example, when X, Y or Z is a β-diketone, as β-diketones, acetone acetone, hexane-2,4-dione, heptane-2,4-dione, heptane-3,5-dione, 5-methyl-hexane- 2,4-dione, octane-2,4-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane-3,5-dione, nonane -2,4-dione, nonane-4,6-dione, 2,2,6,6-tetramethylheptane-3,5-dione, tridecane-6,8-dione, 1-Phenylbutane-1,3-dione, hexafluoroacetone, ascorbic acid, etc.

When X, Y or Z is a β-ketoester, examples of the β-ketoester include methyl acetoacetate, ethyl acetate, n-propyl acetoacetate, isopropyl acetoacetate, ethyl acetate n-Butyl Acetate, 2-Butyl Acetate, 3-Butyl Acetate, Methyl Acetate, Ethyl Acetate, N-Propyl Acetate, Isopropyl Acetate, Propyl Acetate n-Butyl acetate, 2-butyl propionate acetate, 3rd-butyl propionate acetate, benzyl acetyl acetate, dimethyl malonate, diethyl malonate, etc.

In the present invention, iron catalysts other than iron chelate compounds can also be used, and for example, compounds of iron and an alkoxy group, a halogen atom, and an alkoxy group can also be used. In the case of a compound of iron and an alkoxy group, examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, the second butoxy group, the third Butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, 2-ethylhexyl, phenoxy, cyclohexyloxy, benzyloxy, 1-benzylnaphthyloxy and the like.

In the case of the compound of iron and a halogen atom, fluorine, chlorine, bromine, iodine, etc. are mentioned as a halogen atom.

In the case of a compound of iron and an acyloxy group, examples of the acyloxy group include 2-ethylhexanoic acid, octanoic acid, naphthenic acid, resin acids (rosin acid, neoabietic acid, d-pimaric acid, iso- Amino acids such as d-pimaric acid, morohanic acid, gluconic acid, fumaric acid, citric acid, aspartic acid, α-ketoglutaric acid, malic acid, succinic acid, glycine or histidine are aliphatic organic acids as main components; aromatic fatty acids with benzoic acid, cinnamic acid, p-hydroxycinnamic acid, etc. as main components), etc.

In the present invention, among these iron catalysts (D), from the viewpoints of reactivity and curability, iron chelate compounds having β-diketones as ligands are preferred, especially those using tris(acetylacetone) ) iron is preferred. These iron catalysts (D) may be used alone or in combination of two or more.

In the present invention, the binder composition of the present invention contains the iron catalyst (D) in an amount of 0.001 to 0.4 parts by mass, preferably 0.002 to 0.3 parts by mass, relative to 100 parts by mass of the polymer (A). , more preferably 0.003 parts by mass to 0.2 parts by mass, and still more preferably 0.004 parts by mass to 0.1 parts by mass. When the content of the iron catalyst (D) is less than 0.001 parts by mass, the crosslinking properties (degree of crosslinking and curability) immediately after the curing treatment are insufficient, and the appearance of the adhesive layer due to external pressure may easily occur. Defective (pits in the adhesive layer). On the other hand, when it exceeds 0.4 mass part, since the color tone change of an adhesive bond layer arises and it becomes difficult to carry out the inspection in the state stuck to an optical member, it is undesired. (Compound (E) causing keto-enol tautomerism)

The adhesive composition of the present invention may contain a keto-enol tautomer-generating compound (E) (hereinafter, sometimes referred to as "tautomeric compound (E)"). The tautomeric compound (E) refers to a compound that generates tautomerism between a ketone compound (ketone, aldehyde) and an enol, and is a compound that functions as a chelating agent with respect to the iron catalyst (D) described above. By using the above-mentioned tautomeric compound (E), excessive viscosity increase and gelation of the adhesive composition after blending of the crosslinking agent can be suppressed, and the effect of prolonging the pot life of the adhesive composition can be achieved. In particular, when the above-mentioned isocyanate-based crosslinking agent (B) is used as the crosslinking agent, it is particularly meaningful to contain the above-mentioned tautomeric compound (E). This technique can be preferably applied, for example, when the above-mentioned adhesive composition is in the form of an organic solvent solution or a solvent-free form.

As the above-mentioned tautomeric compound (E), various β-dicarbonyl compounds can be used. Specific examples include acetone acetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane β-diketones such as alkane-2,4-dione, 2,6-dimethylheptane-3,5-dione; methyl acetonitrile, ethyl acetate, isopropyl acetoacetate , Acetyl acetates such as 3-butyl acetyl acetate; Acetyl acetates such as ethyl acetate, ethyl acetate, isopropyl acetate, 3-butyl acetyl acetate; Isobutyl acetate Isobutyryl acetates such as ethyl acetate, ethyl isobutyrate, isopropyl isobutyrate acetate, 3rd butyl isobutyrate acetate, etc.; propylene glycol such as methyl malonate, ethyl malonate, etc. acid esters; etc. Among them, acetylacetone and acetylacetate are mentioned as preferable compounds. The compounds that produce keto-enol tautomerism may be used alone or in combination of two or more.

The content of the tautomeric compound (E) is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the polymer (A). When the content of the tautomeric compound (E) is less than 0.5 parts by mass, there may be a problem that a sufficient pot life cannot be obtained. When the content of the tautomeric compound (E) exceeds 10 parts by mass, although the increase in viscosity can be suppressed, the cohesive force of the adhesive layer may be prevented. insufficient. This is presumably because the above-mentioned tautomeric compound remaining in the adhesive layer after the curing treatment acts as a plasticizer and reduces the cohesive force.

In addition, the adhesive composition of the present invention may contain other known additives. For example, powders such as colorants and pigments, surfactants, plasticizers, and tackifiers may be appropriately added according to the intended use. , low molecular weight polymers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powder, particulate , foil, etc. <Adhesive layer and surface protection film>

The adhesive layer of the present invention is preferably obtained by crosslinking the above-mentioned adhesive composition. By appropriately adjusting the structural unit of the polymer (A), the composition ratio, the selection of the crosslinking agent, the addition ratio, etc., the crosslinking can be carried out, and the adhesive force stability, releasability, low contamination and heat resistance can be obtained. adhesive layer and surface protection film.

The surface protective film of the present invention is preferably obtained by forming the above-mentioned adhesive layer on at least one surface of the support. The above-mentioned surface protective film is a material obtained by forming the above-mentioned adhesive layer on at least one side of the support. At this time, the cross-linking of the adhesive composition is usually carried out after the coating of the adhesive composition, but it can also be applied on the separator. The adhesive composition is prepared and dried, and then the adhesive layer containing the cross-linked adhesive composition on the separator is transferred to the support.

In addition, the method of forming the adhesive layer on the support is not particularly limited. For example, it can be prepared by applying the above-mentioned adhesive composition (solution) to the support, drying and removing the polymerization solvent, etc. An adhesive layer is formed. Then, curing may be performed for the purpose of adjusting the component transfer of the adhesive layer, adjusting the crosslinking reaction, and the like. In addition, when applying the adhesive composition on the support to produce a surface protection film, one or more solvents other than the polymerization solvent may be newly added to the above-mentioned adhesive composition in order to allow the adhesive composition to be uniformly coated on the support.

Moreover, as a formation method of the adhesive bond layer of this invention, the well-known method used for manufacture of a surface protection film (adhesive sheet) can be used. Specifically, for example, roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating method, etc. are mentioned.

The thickness of the adhesive layer of the present invention is usually 1 μm to 100 μm, preferably 3 μm to 50 μm, and more preferably 5 μm to 30 μm. When the thickness of the pressure-sensitive adhesive layer is within the above-mentioned range, it is easy to obtain an appropriate balance between releasability and adhesiveness, which is preferable. ＜Support body＞

The above-mentioned support is not particularly limited as long as it can be formed into a sheet or film, and examples thereof include polyethylene, polypropylene, poly-1-butene, and poly-4-methyl-1-pentane. ethylene, ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene-vinyl alcohol copolymers, polymers with cyclic or norbornene structures Polyolefin films such as olefins, polyester films such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyacrylate films, polystyrene films, nylon 6. Polyamide films such as nylon 6,6, some aromatic polyamides, polyvinyl chloride films, polyvinylidene chloride films, polycarbonate films, polyvinyl fluoride films, polyimide films, polyvinyl alcohol film etc.

The thickness of the support body in this invention is about 5 micrometers - about 200 micrometers normally, Preferably it is about 10 micrometers - about 100 micrometers, More preferably, it is about 20 micrometers - about 75 micrometers.

The above-mentioned support can also be subjected to mold release and antifouling treatment using polysiloxane-based, fluorine-containing, long-chain alkyl-based or aliphatic amide-based mold release agents, silica powder, etc. Acid treatment, alkali treatment, primer treatment, corona treatment, plasma treatment, UV treatment and other easy-adhesion treatments, coating type, kneading type, vapor deposition type and other antistatic treatments.

The surface protective film of the present invention may be formed in a form wound up in a roll shape, or may be formed in a form in which sheets are laminated. That is, the surface protective film of this invention may have arbitrary forms, such as a sheet shape, a tape shape, and a film shape. In addition, according to the purpose of use, it may be cut into an appropriate form, punched, or the like may be performed. ＜Spacer＞

The surface protection film of the present invention can be attached to a separator for the purpose of protecting the surface of the adhesive layer as needed.

As a material constituting the separator, there are paper and a plastic film, and from the viewpoint of excellent surface smoothness, a plastic film is preferably used. The film is not particularly limited as long as it can protect the adhesive layer, and examples thereof include polyethylene films, polypropylene films, polybutene films, polybutadiene films, and polymethylpentene films. , polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

The thickness of the spacer is usually 5 μm to 200 μm, preferably 8 μm to 100 μm, and more preferably 10 μm to 50 μm. The separator can also be subjected to mold release and antifouling treatment using polysiloxane-based, fluorine-containing, long-chain alkyl-based or aliphatic amide-based mold release agents, silica powder, etc., as required, or Antistatic treatment such as coating type, kneading type, vapor deposition type, etc.

The surface protection film disclosed here may be implemented to include other layers in addition to the support and the pressure-sensitive adhesive layer. As said other layer, the primer layer (anchor layer) etc. which can improve the anchoring property of an antistatic layer and an adhesive bond layer are mentioned.

The optical member of the present invention is preferably protected by the above-mentioned surface protection film. The above-mentioned surface protective film can prevent an increase in the adhesive force after sticking and storage of the adhesive layer, and has excellent re-peelability, so it can be used for surface protection purposes (surface protective film) during processing, transportation, and shipping, etc. The surface protection film useful for the surface of the said optical member (polarizing plate etc.). Moreover, since the color tone change of the adhesive bond layer which comprises a surface protection film is suppressed, inspection can be performed in the state which bonded the surface protection film to an optical member, and it can contribute to quality improvement. Example

Hereinafter, although the Example etc. which show the structure and effect of this invention concretely are demonstrated, this invention is not limited to these Examples. In addition, the evaluation item in an Example etc. was measured as follows. <Preparation of Acrylic Polymer 1>

96.2 parts by mass of 2-ethylhexyl acrylate (2EHA), 3.8 parts by mass of hydroxyethyl acrylate (HEA), 2 , 0.2 parts by mass of 2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate, nitrogen was introduced while stirring slowly, the liquid temperature in the flask was maintained at about 65°C, and a polymerization reaction was carried out for 6 hours to prepare Acrylic polymer 1 solution (40 mass %). The weight average molecular weight (Mw) of the said acrylic polymer 1 was 540,000, and the glass transition temperature (Tg) was -68 degreeC. <Preparation of Acrylic Polymer 2>

98.5 parts by mass of 2-ethylhexyl acrylate (2EHA) and 1.5 parts by mass of 4-hydroxybutyl acrylate (4HBA) were put into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a condenser as polymerization initiators 0.2 parts by mass of 2,2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate, nitrogen was introduced while stirring slowly, the liquid temperature in the flask was maintained at about 60°C, and a polymerization reaction was carried out for 6 hours, thereby An acrylic polymer 2 solution (40 mass %) was prepared. The weight average molecular weight (Mw) of the said acrylic polymer 2 was 500,000, and the glass transition temperature (Tg) was -70 degreeC. <Preparation of Acrylic Polymer 3>

98.48 parts by mass of 2-ethylhexyl acrylate (2EHA), 1.5 parts by mass of 4-hydroxybutyl acrylate (4HBA), and acrylic acid (AA) were put into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a condenser. 0.02 part by mass, 0.2 part by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 150 parts by mass of ethyl acetate, nitrogen gas was introduced while stirring slowly, and the liquid temperature in the flask was kept at about 60°C And the polymerization reaction was performed for 6 hours, and the acrylic polymer 3 solution (40 mass %) was prepared. The weight average molecular weight (Mw) of the said acrylic polymer 3 was 500,000, and the glass transition temperature (Tg) was -70 degreeC. <Preparation of Acrylic Polymer 4>

98.494 parts by mass of 2-ethylhexyl acrylate (2EHA), 1.5 parts by mass of 4-hydroxybutyl acrylate (4HBA), and acrylic acid (AA) were put into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a condenser. 0.006 part by mass, 0.2 part by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 150 parts by mass of ethyl acetate, nitrogen gas was introduced while stirring slowly, and the liquid temperature in the flask was kept at about 60°C And the polymerization reaction was performed for 6 hours, and the acrylic polymer 4 solution (40 mass %) was prepared. The weight average molecular weight (Mw) of the said acrylic polymer 4 was 470,000, and the glass transition temperature (Tg) was -70 degreeC. <Preparation of Acrylic Polymer 5>

90.893 parts by mass of 2-ethylhexyl acrylate (2EHA), 9.089 parts by mass of 4-hydroxybutyl acrylate (4HBA), and acrylic acid (AA) were put into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a condenser. 0.018 parts by mass, 0.2 parts by mass of 2,2'-azobisisobutyronitrile as polymerization initiators, and 150 parts by mass of ethyl acetate, nitrogen gas was introduced while stirring slowly, and the liquid temperature in the flask was kept at about 60°C And the polymerization reaction was performed for 6 hours, and the acrylic polymer 5 solution (40 mass %) was prepared. The weight average molecular weight (Mw) of the said acrylic polymer 5 was 640,000, and the glass transition temperature (Tg) was -67 degreeC. <Example 1> [Preparation of acrylic adhesive solution]

The above-mentioned acrylic polymer 1 solution (40 mass %) was diluted to 25 mass % with ethyl acetate, and 400 mass parts of the solution (solid content 100 mass parts) was added as a crosslinking agent as a trifunctional isocyanate compound. Trimethylolpropane adduct of toluene diisocyanate (Tosoh Corporation, Coronate L) 5.33 parts by mass (4 parts by mass of solid content), dioctyltin dilaurate (dioctyltin dilaurate) as a crosslinking catalyst as a tin catalyst ( Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) 2 mass parts (solid content 0.02 mass parts), tris(acetylacetonate) iron as iron catalyst (Nihon Chemical Industry Co., Ltd., Nacem Fe(III), 1 mass % ethyl acetate solution) 1 mass part (solid content 0.01 mass part), and 3 mass parts of acetylacetone were mixed and stirred, and the acrylic adhesive solution was prepared. [Production of surface protective film]

The above-mentioned acrylic adhesive solution was applied to the surface opposite to the antistatic treated surface of a polyethylene terephthalate film with an antistatic treatment layer (manufactured by Mitsubishi Plastics Corporation, DIAFOIL T100G38, thickness 38 μm), and heated at 130°C. Under heating for 20 seconds, an adhesive layer with a thickness of 15 μm was formed. Next, the polysiloxane-treated surface of a polyethylene terephthalate film (thickness: 25 μm) whose one side had been polysiloxane-treated was bonded to the surface of the above-mentioned adhesive layer to prepare a surface protection film. . <Example 2>

A surface protection film was produced by the same method as in Example 1, except that the acrylic polymer 2 was used in place of the acrylic polymer 1 used in Example 1. <Example 3>

A surface protection film was produced by the same method as in Example 1, except that the acrylic polymer 3 was used in place of the acrylic polymer 1 used in Example 1. <Example 4>

A surface protection film was produced by the same method as in Example 1, except that the acrylic polymer 4 was used in place of the acrylic polymer 1 used in Example 1. <Example 5>

Instead of 2 parts by mass (solid content) used in Example 1, 3 parts by mass (0.03 parts by mass of solid content) of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) was used. component 0.02 mass part), using tris(acetylacetonate) iron (manufactured by Nippon Chemical Industries, Ltd., Nacem Fe (III), 1 mass % ethyl acetate solution) 0.5 mass part (solid content 0.005 mass part) instead of 1 mass part A surface protection film was produced by the same method as in Example 1, except for (0.01 parts by mass of solid content). <Example 6>

In place of 1 part by mass used in Example 1, 3 parts by mass (solid content: 0.03 part by mass) of tris(acetylacetonate) iron (manufactured by Nippon Chemical Industries, Ltd., Nacem Fe(III), 1 mass % ethyl acetate solution) was used A surface protection film was produced by the same method as in Example 1, except for (0.01 parts by mass of solid content). <Example 7>

In place of 1 part by mass used in Example 1, 5 parts by mass (solid content 0.05 part by mass) of tris(acetylacetonate) iron (manufactured by Nippon Chemical Industries, Ltd., Nacem Fe(III), 1 mass % ethyl acetate solution) was used A surface protection film was produced by the same method as in Example 1, except for (0.01 parts by mass of solid content). <Example 8>

In place of 1 part by mass used in Example 1, 8 parts by mass (solid content: 0.08 part by mass) of tris(acetylacetonate) iron (manufactured by Nippon Chemical Industries, Ltd., Nacem Fe(III), 1 mass % ethyl acetate solution) was used A surface protection film was produced by the same method as in Example 1, except for (0.01 parts by mass of solid content). <Example 9>

Instead of 2 parts by mass (solid content) used in Example 1, 3 parts by mass (0.03 parts by mass of solid content) of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) was used. A surface protection film was produced by the same method as in Example 1, except that the composition was 0.02 parts by mass). <Example 10>

5 parts by mass (solid content 0.05 parts by mass) of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) was used instead of 2 mass parts (solid content) used in Example 1. A surface protection film was produced by the same method as in Example 1, except that the composition was 0.02 parts by mass). <Example 11>

8 parts by mass (solid content 0.08 parts by mass) of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) was used instead of 2 mass parts (solid content) used in Example 1. A surface protection film was produced by the same method as in Example 1, except that the composition was 0.02 parts by mass). <Example 12>

Instead of 2 parts by mass (solid content) used in Example 1, 3 parts by mass (0.03 parts by mass of solid content) of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) was used. A surface protection film was produced by the same method as in Example 1, except that 9 parts by mass of acetone acetone was used instead of 3 parts by mass. <Example 13>

8 parts by mass (solid content 0.08 parts by mass) of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) was used instead of 2 mass parts (solid content) used in Example 1. A surface protection film was produced by the same method as in Example 1, except that 9 parts by mass of acetone acetone was used instead of 3 parts by mass. <Example 14>

In place of the acrylic polymer 1 used in Example 1, acrylic polymer 5 was used, and as a crosslinking agent, a trimethylolpropane adduct of toluene diisocyanate (manufactured by Tosoh Corporation, manufactured by Tosoh Corporation) was used as a trifunctional isocyanate compound. A surface protection film was produced by the same method as in Example 1, except that Coronate L) 2.72 parts by mass (2 parts by mass of solid content) instead of 5.33 parts by mass (4 parts by mass of solid content). <Example 15>

In place of the trifunctional isocyanate compound used in Example 14, 2 parts by mass (2 parts by mass of solid content) of the isocyanurate form of hexamethylene diisocyanate (manufactured by Mitsui Chemicals, Ltd., Coronate HX) was used. A surface protection film was produced in the same manner as in Example 14, except for 2.72 parts by mass (2 parts by mass of solid content) of a trimethylolpropane adduct (manufactured by Tosoh Corporation, Coronate L). <Comparative Example 1>

Except for not using 1 part by mass (solid content 0.01 part by mass) of tris(acetylacetonate) iron (manufactured by Nippon Chemical Industries, Ltd., Nacem Fe(III), 1 mass % ethyl acetate solution) used in Example 1, A surface protection film was produced by the same method as Example 1. <Comparative Example 2>

In place of 2 parts by mass (solid content) used in Example 1, 50 parts by mass (0.5 parts by mass of solid content) of dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) was used. component 0.02 mass parts), and 1 mass part (solid content 0.01 mass parts) is not used (Nihon Chemical Industry Co., Ltd., Nacem Fe (III), 1 mass % ethyl acetate solution), except Other than that, a surface protection film was produced by the same method as Example 1. <Comparative Example 3>

Except not using the dioctyltin dilaurate used in Example 1 (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) 2 mass parts (solid content 0.02 mass parts), by A surface protection film was produced in the same manner as in Example 1. <Comparative Example 4>

Instead of using dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., EMBILIZER OL-1, 1 mass % ethyl acetate solution) 2 mass parts (solid content 0.02 mass parts) used in Example 1, three ( Acetate acetone) iron (manufactured by Nippon Chemical Industries, Ltd., Nacem Fe(III), 1 mass % ethyl acetate solution) 50 mass parts (solid content 0.5 mass parts) instead of 1 mass part (solid content 0.01 mass parts), except Otherwise, a surface protection film was produced by the same method as Example 1. <Measurement of weight average molecular weight (Mw) of acrylic polymer>

The weight average molecular weight (Mw) of the acrylic polymer was measured by GPC (gel permeation chromatography). Apparatus: Tosoh Corporation, HLC-8220GPC Column: Sample column: Tosoh Corporation, TSKguardcolumn Super HZ-H (1) + TSKgel Super HZM-H (2) Reference column: Tosoh Corporation, TSKgel Super H-RC (1 piece) Flow rate: 0.6ml/min Injection volume: 10μl Column temperature: 40℃ Eluent: THF Injection concentration: 0.2% by mass Detector: Differential refractometer The molecular weight (Mw) was calculated in terms of polystyrene. <Theoretical value of glass transition temperature (Tg)>

Regarding the glass transition temperature (Tg) (° C.) of the acrylic polymers obtained in the examples and comparative examples, the following literature values were used as the glass transition temperature Tgn (° C.) of the homopolymer obtained from each monomer, and the It is calculated|required by the following formula.

Formula: 1/(Tg+273)=Σ[Wn/(Tgn+273)] [In the formula, Tg(°C) represents the glass transition temperature of the copolymer, Wn(-) represents the mass fraction of each monomer, Tgn (° C.) represents the glass transition temperature of the homopolymer obtained from each monomer, and n represents the type of each monomer. ] Literature values: 2-ethylhexyl acrylate (2EHA): -70°C Hydroxyethyl acrylate (HEA): -15°C 4-hydroxybutyl acrylate (4HBA): -32°C acrylic acid (AA): 106°C

Note that, as literature values, "Synthesis, Design, and Development of New Applications of Acrylic Resins" (published by the Central Business Development Center Publishing Department) and "Polymer Handbook" (John Wiley & Sons) were referred to. <Measurement of pot life>

The binder solution was prepared, sealed in a 1 mL glass sample vial, and left at room temperature for 8 hours. After that, the "pot life" was judged by visually observing the fluidity of the adhesive solution. The criteria for determination are as follows. ○: The binder solution flows when the sample vial is inverted. ×: The adhesive solution did not flow when the sample vial was inverted. <Reaction rate of isocyanate group by catalyst>

The surface of the adhesive layer was measured by the ATR (Attenuated Total Reflection) method using a Fourier transform infrared spectrometer (FT-IR) analyzer (manufactured by PerkinElmer, model "Frontier FT-IR"). IR peak. As "IR peak intensity of isocyanate group", the peak intensity at 2275 cm-1 was used. In addition, the said isocyanate group is an isocyanate group derived from an isocyanate type crosslinking agent (isocyanate compound). In this evaluation, the ratio (reaction rate) used (disappeared) in the crosslinking reaction of the isocyanate group was evaluated based on the change in the IR peak intensity of the isocyanate group. Immediately after the production of the surface protection film (immediately after curing the adhesive composition), the "IR peak intensity (immediately after production)" on the surface of the adhesive layer was measured, and aged at room temperature (23°C) for 7 days. The "IR peak intensity (after 7 days at room temperature)" was then measured. The "reaction rate of the isocyanate group based on the catalyst (immediately after production)" was calculated by the following formula. "Reaction rate of isocyanate group based on catalyst (immediately after production)" = 100×{(IR peak intensity of adhesive layer that is the same except that no catalyst is used) - (IR peak intensity of adhesive layer (immediately after production) )}/(IR peak intensity of the same adhesive layer except that the catalyst was not used) The "reaction rate of the isocyanate group based on the catalyst (after 7 days at room temperature)" was calculated from the following formula. "Reaction rate of isocyanate group based on catalyst (after 7 days at room temperature)"=100×{(IR peak intensity of adhesive layer that is the same except that no catalyst is used)-(IR peak intensity of adhesive layer (room temperature) After 7 days))}/(IR peak intensity of the same adhesive layer except that no catalyst was used)

In addition, 10 or more are preferable as the reaction rate (immediately after production) of the isocyanate group by the said catalyst, 20 or more are more preferable, and 25 or more are especially preferable. It is preferable that the reaction rate by the catalyst (immediately after production) is within the above range, since the occurrence of poor appearance of the adhesive (dimples on the surface of the adhesive) due to external pressure can be reduced.

Moreover, 80 or more are preferable as the reaction rate (after 7 days of room temperature) of the isocyanate group by the said catalyst, 85 or more are more preferable, and 90 or more are especially preferable. When the reaction rate by the catalyst (after 7 days at room temperature) is within the above range, the increase in the adhesive force due to the reaction between the unreacted and remaining isocyanate-based crosslinking agent and the adherend can be suppressed, which is preferable. <Hue b value>

The surface protective film of each example was aged for 7 days at room temperature, then cut into a size of 50 mm in width and 50 mm in length, the separator was peeled off from the surface of the adhesive layer of the surface protective film, and then a high-speed integrating sphere type transmittance meter was used. (Model "DOT-3C" manufactured by Murakami Color Institute Co., Ltd.) The "b value" was measured. The b value refers to the Hunter Lab value. In addition, the said b value becomes like this. Preferably it is 2.00 or less, More preferably, it is 1.50 or less, More preferably, it is 1.00 or less. When the above-mentioned b value is within the above-mentioned range, it is preferable that the change in the color tone of the adhesive layer is a level that does not cause problems in practical use (the adhesive layer is not colored yellow or red) when used for an optical member. <Measurement of Adhesion>

The surface protective film of each example was aged for 7 days at room temperature, then cut into a size of 25 mm in width and 100 mm in length, and the separator was peeled off from the surface of the adhesive layer of the surface protective film, and then temporarily crimped and bonded with a manual roller. On the surface of the polarizing plate of the glass plate (manufactured by Nitto Denko Co., Ltd., triacetyl cellulose-based polarizing plate, width: 70 mm, length: 100 mm), a small laminator (pressure of 0.25 MPa, pressure of 0.3 m/min) was used speed) was crimped to prepare a sample for evaluation. The above-mentioned sample was left at room temperature (23°C) for 30 minutes, and then peeled off with a universal tensile tester at a peeling angle of 180° and a tensile speed of 30 m/min, as "initial adhesion". Force" (N/25mm) was measured. In addition, after the above-mentioned sample was left to stand in an environment of 70° C. for 1 day (after aging treatment), it was peeled with a universal tensile tester so that the peeling angle was 180° and the tensile speed was 30 m/min, and the measurement was carried out. "Adhesion after pasting and saving" (N/25mm). The measurement was performed in an environment of 23°C and 50% RH.

The initial adhesive force is preferably 0.1N/25mm~7.0N/25mm, more preferably 0.1N/25mm~5.0N/25mm, still more preferably 0.1N/25mm~4.0N/25mm. It is preferable that the said adhesive force is excellent in temporary fixability and releasability when it exists in the said range.

As for the adhesive force after sticking and storing, it is preferably 0.3N/25mm~10.0N/25mm, more preferably 0.3N/25mm~8.0N/25mm, still more preferably 0.3N/25mm~4.0N/25mm . If the above-mentioned adhesive force is within the above-mentioned range, the increase in the adhesive force can be suppressed even after sticking and storage, and the re-peelability is excellent, which is preferable.

In addition, the abbreviations in Table 1 are as follows. <Crosslinking agent (B)> C/L: Trimethylolpropane/toluene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate L") C/HX: isocyanurate of hexamethylene diisocyanate Form (manufactured by Tosoh Corporation, trade name "Coronate HX") <Tin catalyst (C) and iron catalyst (D)> OL-1: Dioctyltin dilaurate (manufactured by Tokyo Fine Chemical Co., Ltd., trade name "EMBILIZER OL" -1") Nacem Fe(III): Tris(acetylacetonate)iron (manufactured by Nippon Chemical Industries, Ltd., trade name "Nacem Fe(III)")

Table 1

Table 2

From Table 2, it can be confirmed that in all the examples, the pot life of the adhesive composition is sufficiently long, even after the adhesive composition is cured (immediately after production and after drying) and after the aging treatment, based on The reaction rate of the isocyanate group of the catalyst was also high, and it was also confirmed that an adhesive layer with high crosslinkability (degree of crosslinking) was obtained, and the adhesive force was suppressed even after the adhesive layer was pasted and stored. It is excellent in re-peelability and can also prevent the color tone of the adhesive layer from changing, and can be inspected even in the state of being adhered to an optical member.

On the other hand, it was confirmed from Table 2 that in Comparative Example 1, since the iron catalyst (D) was not compounded, the crosslinkability (degree of crosslinking) immediately after the curing treatment (after the drying treatment) was insufficient, and the catalyst-based The reaction rate of the isocyanate group was low, and the reaction with the crosslinking agent (B) did not proceed sufficiently. In addition, in Comparative Example 2, since the tin catalyst (C) was blended in an amount larger than the predetermined amount and the iron catalyst (D) was not blended, it was confirmed that the crosslinking reaction in the binder solution proceeded and the pot life was short. In addition, in Comparative Example 3, since the tin catalyst (C) was not compounded, it was confirmed that the reaction between the isocyanate crosslinking agent and the adherend proceeded after aging at room temperature, the adhesive strength after the sticking and storage was high, and the increase in the adhesive strength was prevented. Poor performance and re-peelability. In Comparative Example 4, since the tin catalyst (C) was not compounded and the iron catalyst (D) was compounded in an amount larger than a predetermined amount, it was confirmed that b related to the change in color tone caused by the iron catalyst that causes red coloration The value is very high and does not have a level practically used as a surface protection film for optical members.

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Claims (5)

An adhesive composition, characterized in that, with respect to 100 parts by mass of a polymer (A) having an active hydrogen functional group, the adhesive composition contains an isocyanate-based crosslinking agent (B), 0.001 parts by mass to 0.4 parts by mass The compound (C) with tin as the active center and the compound (D) with iron as the active center of 0.001 parts by mass to 0.4 parts by mass; with respect to 100 parts by mass of the polymer (A), the binder combination The product contains 0.1 parts by mass to 20 parts by mass of the crosslinking agent (B); the polymer (A) is an acrylic polymer. The adhesive composition according to claim 1, wherein the active hydrogen-containing functional group is a hydroxyl group and/or a carboxyl group. An adhesive layer, characterized in that the adhesive layer is obtained by crosslinking the adhesive composition of claim 1 or 2. A surface protection film, characterized in that the surface protection film is obtained by forming the adhesive layer of claim 3 on at least one side of a support. An optical member, characterized in that the optical member is protected by the surface protection film of claim 4.