JP6519786B2 - Adhesive film - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive film that can be suitably used as a surface protective film.

  A surface protection film is used for the purpose of preventing dirt and scratches on the surface of glass, plastic and the like.

  As a structure of the said surface protective film, what laminated | stacked plastic films, such as a polyethylene terephthalate film, an adhesive layer, and a mold release film, for example is utilized (for example, refer patent document 1). Moreover, as an adhesive used for the said adhesive layer, a silicon adhesive, an acrylic adhesive, a urethane adhesive etc. are widely utilized.

  In the manufacturing process of the touch panel peripheral member especially used for a smart phone or a tablet, utilization of a protective film which uses a urethane adhesive increases from efficiency and price advantage of pasting work. However, when a urethane-based protective film is used, there is a problem in that the adherend is contaminated in a moist and heat-resistant environment at the time of the production process and the subsequent conveyance process.

JP 2013-124293 A

  The problem to be solved by the present invention is to provide a pressure-sensitive adhesive film which is excellent in paintability and which causes less contamination to the adherend even in a moist and heat resistant environment.

  The present invention provides a pressure-sensitive adhesive film characterized in that a polyethylene terephthalate substrate (i), an acrylic pressure-sensitive adhesive layer (ii) and a urethane pressure-sensitive adhesive layer (iii) are sequentially laminated.

  The pressure-sensitive adhesive film of the present invention is excellent in paintability, and has less contamination to the adherend even in a moist and heat resistant environment. The pressure-sensitive adhesive film of the present invention can be particularly suitably used as a surface protective film.

  The pressure-sensitive adhesive film of the present invention is obtained by sequentially laminating a polyethylene terephthalate substrate (i), an acrylic pressure-sensitive adhesive layer (ii) and a urethane pressure-sensitive adhesive layer (iii).

  The pressure-sensitive adhesive film of the present invention has excellent wettability due to the above-described constitution, and causes less contamination to the adherend even when used in a moist and heat resistant environment (hereinafter referred to as "stain resistance"). It is a thing. As a mechanism by which this effect can be obtained, by using a urethane adhesive excellent in flexibility as the adhesive surface to the adherend, excellent wettability to the adherend can be expressed, and the acrylic adhesive layer is made of polyethylene. A decomposition product derived from a polyethylene terephthalate substrate (a hydrolyzate of terephthalic acid, a plasticizer, etc.) that causes adherend contamination under high temperature and high humidity conditions by providing between a terephthalate substrate and a urethane adhesive layer Since additives, etc.) can be captured, excellent stain resistance can be developed.

  The total value of the thickness of the acrylic pressure-sensitive adhesive layer (ii) and the thickness of the urethane pressure-sensitive adhesive layer (iii) in the pressure-sensitive adhesive film of the present invention is in the range of 5 to 50 μm which can be suitably used as a surface protective film. Is preferably, and more preferably in the range of 8 to 20 μm. Although the total value of the thickness is a thick film as a pressure-sensitive adhesive layer for a surface protective film, the pressure-sensitive adhesive film of the present invention can achieve both excellent wettability and stain resistance even with the thickness.

  As the ratio [(ii) / (iii)] of the thickness of the acrylic pressure-sensitive adhesive layer (ii) and the urethane pressure-sensitive adhesive layer (iii), both wettability and stain resistance can be achieved at a high level; The range of 85 to 60/40 is preferred, the range of 20/80 to 55/45 is more preferred, and the range of 20/80 to 40/60 is even more preferred.

  The gel fraction (toluene) of the entire pressure-sensitive adhesive layer of the pressure-sensitive adhesive film is preferably 70% or more, and more preferably in the range of 72 to 85%, because it can achieve both wettability and stain resistance at high levels. . In addition, the measuring method of the gel fraction of the whole adhesive layer of the said adhesive film is described in the Example mentioned later.

  The polyethylene terephthalate substrate (i) is a non-release-treated substrate obtained using polyethylene terephthalate as a raw material, and a common polyethylene terephthalate substrate, a polyethylene terephthalate substrate subjected to a corona treatment, an easy adhesion treatment The applied polyethylene terephthalate base material etc. can be used.

  The thickness of the polyethylene terephthalate substrate (i) is, for example, in the range of 20 to 200 μm.

  The acrylic pressure-sensitive adhesive layer (ii) is formed of an acrylic pressure-sensitive adhesive containing a (meth) acrylic resin. In the present invention, “(meth) acrylic” indicates acrylic and / or methacrylic, “(meth) acrylate” indicates acrylate and / or methacrylate, and “(meth) acryloyl” indicates acryloyl. And / or methacryloyl is shown.

  As the acrylic pressure-sensitive adhesive, it is preferable to use one that can form a crosslinked structure, because it can further improve the capture ability of the decomposition product derived from the polyethylene terephthalate base material (i), specifically, hydroxyl group and / or hydroxyl group It is preferred to use one containing a (meth) acrylic resin (X-1) having a carboxyl group and a crosslinking agent (X-2).

  Examples of the (meth) acrylic resin (X-1) include (meth) acrylic acid alkyl ester (X-1-1) and a (meth) acrylic compound (X-1-2) having a hydroxyl group and / or What is obtained by polymerizing a (meth) acrylic compound (X) having a carboxyl group-containing (meth) acrylic compound (X-1-3) as an essential component can be used.

  The number of carbon atoms of the alkyl group of the (meth) acrylic acid alkyl ester (X-1-1) is in the range of 1 to 20 from the viewpoint of availability of raw materials and good initial tack. Is preferable, the range of 2 to 12 is more preferable, and the range of 4 to 8 is further preferable.

  Specific examples of the (meth) acrylic acid alkyl ester (X-1-1) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate and i-butyl (meth) acrylate. , T-butyl (meth) acrylate, n-propyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meta) ) Acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and the like. These compounds may be used alone or in combination of two or more. Among these, n-butyl (meth) acrylate and / or 2-ethylhexyl (meth) acrylate is preferably used in terms of the polymerizability and the initial tack.

  The amount of the (meth) acrylic acid alkyl ester (X-1-1) used is 50 to 99.5% by mass of the (meth) acrylic compound (X) from the viewpoint of obtaining a good initial tack. It is preferable that it is a range, and the range of 60-97 mass% is more preferable.

  Examples of the (meth) acrylic compound (X-1-2) having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyhexyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylic, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) Acrylate, 12-hydroxy lauryl (meth) acrylate, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, glycerol (meth) acrylate and the like can be used. These compounds may be used alone or in combination of two or more.

  In the case of using the (meth) acrylic compound (X-1-2) having a hydroxyl group, a good crosslinking reaction with the crosslinking agent (X-2) is formed, and a good initial tack and contamination resistance are formed. It is preferable that it is the range of 0.001-20 mass% in said (meth) acrylic compound (X) from the point in which property is obtained, and the range of 0.01-5 mass% is more preferable.

  As the (meth) acrylic compound (X-1-3) having a carboxyl group, for example, (meth) acrylic acid, methyl (meth) acrylate, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate and the like are used be able to. These compounds may be used alone or in combination of two or more.

  In the case of using the (meth) acrylic compound (X-1-3) having a carboxyl group, a good crosslinking reaction with the crosslinking agent (X-2) is formed, and a good initial tack and resistance are obtained. The range of 0.1 to 20% by mass in the (meth) acrylic compound (X) is preferable, and the range of 0.5 to 15% by mass is more preferable, from the viewpoint of obtaining the contamination property.

  When obtaining said (meth) acrylic resin (X-1), you may use another vinyl compound together.

  Examples of the other vinyl compounds include methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, vinyl acetate, vinyl propionate, vinyl laurate, styrene, chlorostyrene, chloromethyl styrene, α-methyl styrene Methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether and the like can be used. These compounds may be used alone or in combination of two or more.

  As a manufacturing method of said (meth) acrylic resin (X-1), the radical polymerization method resulting from the polymerizable double bond which the said (meth) acrylic compound (X) has is mentioned, for example. Specifically, the component (meth) acrylic compound (X), the other vinyl compound as required, and the radical polymerization initiator are preferably mixed and stirred at a temperature of 40 to 90 ° C. The method of advancing superposition | polymerization is mentioned.

  Examples of the polymerization initiator include inorganic peroxides such as hydrogen peroxide, potassium persulfate, sodium persulfate and ammonium persulfate; benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, cumene hydroperoxide Organic peroxides such as oxides; 2,2′-azobis- (2-aminodipropane) dihydrochloride, 2,2′-azobis- (N, N′-dimethylene isobutylamidine) dihydrochloride, 2, 2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, azobisisobutyronitrile, 2,2'-azobis (2-methylbutyro) An azo compound such as nitrile) can be used. These polymerization initiators may be used alone or in combination of two or more.

  The amount of the polymerization initiator used is preferably in the range of 0.001 to 5% by mass in the charged raw material of the (meth) acrylic resin (X-1), from the viewpoint of obtaining good polymerizability.

  The weight average molecular weight of the (meth) acrylic resin (X-1) is preferably in the range of 200,000 to 1,000,000 from the viewpoint of obtaining good initial tack and stain resistance. More preferably, it is in the range of 300,000 to 800,000. In addition, the weight average molecular weight of said (meth) acrylic resin (X-1) shows the value obtained by measuring on condition of the following by gel permeation chromatography (GPC) method.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were used in series connection.
"TSKgel G5000" (7.8 mm ID × 30 cm) × 1 "TSK gel G 4000" (7.8 mm ID × 30 cm) × 1 "TSK gel G 3000" (7.8 mm ID × 30 cm) × 1 This "TSKgel G2000" (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
Tosoh Corporation "TSKgel standard polystyrene A-500"
Tosoh Corporation "TSKgel standard polystyrene A-1000"
Tosoh Corporation "TSKgel standard polystyrene A-2500"
Tosoh Corporation "TSKgel standard polystyrene A-5000"
Tosoh Corporation "TSKgel standard polystyrene F-1"
Tosoh Corporation "TSKgel standard polystyrene F-2"
Tosoh Corporation "TSKgel standard polystyrene F-4"
Tosoh Corporation "TSKgel standard polystyrene F-10"
Tosoh Corporation "TSKgel standard polystyrene F-20"
Tosoh Corporation "TSKgel standard polystyrene F-40"
Tosoh Corporation "TSKgel standard polystyrene F-80"
Tosoh Corporation "TSKgel standard polystyrene F-128"
Tosoh Corporation "TSKgel standard polystyrene F-288"
Tosoh Corporation "TSKgel standard polystyrene F-550"

  The amount of the (meth) acrylic resin (X-1) used is preferably in the range of 50 to 99.5% by mass in the acrylic pressure-sensitive adhesive, from the viewpoint of being able to further improve the initial tack and stain resistance. The range of 80 to 95% by mass is more preferable.

  As said crosslinking agent (X-2), an epoxy crosslinking agent, a polyisocyanate crosslinking agent, a melamine crosslinking agent, a metal chelate crosslinking agent etc. can be used, for example. These crosslinking agents (X-2) may be used alone or in combination of two or more. Among these, an epoxy cross-linking agent and / or a polyisocyanate cross-linking agent are formed from the viewpoint of forming a good cross-linking structure with the (meth) acrylic resin (X-1) and obtaining good initial tack and stain resistance. It is preferred to use.

  Examples of the epoxy crosslinking agent include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol poly Glycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl -M-xylene diamine etc. can be used. These crosslinking agents may be used alone or in combination of two or more.

  Examples of the polyisocyanate crosslinking agent include polyisocyanates such as tolylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate and xylylene diisocyanate; trimethylolpropane of hexamethylene diisocyanate Adduct, trimethylolpropane adduct of tolylene diisocyanate, trimethylolpropane adduct of isophorone diisocyanate, trimethylolpropane adduct of xylylene diisocyanate, nurate of hexamethylene diisocyanate, nurate of tolylene diisocyanate, isophorone diisocyanate Isocyanurate of bets, isocyanurate of xylylene diisocyanate and the like can be used. These crosslinking agents may be used alone or in combination of two or more.

  The amount of the crosslinking agent (X-2) used is preferably in the range of 0.001 to 20% by mass in the acrylic pressure-sensitive adhesive, from the viewpoint of being able to further improve the initial tack and stain resistance. The range of 005 to 10% by mass is more preferable.

  The above-mentioned acrylic adhesive may contain other additives as needed.

  Examples of the other additives include organic solvents, photopolymerization initiators, antioxidants, leveling agents, tackifiers, waxes, heat stabilizers, antistatic agents, flame retardants, foam stabilizers, antifoam agents, An antiblocking agent, a silane coupling agent, etc. can be used. These additives may be used alone or in combination of two or more.

  As the organic solvent, for example, toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, hexane, acetone, cyclohexanone, 3-pentanone, acetonitrile, propionitrile, isobutyronitrile, valeronitrile, dimethyl sulfoxide, dimethylformamide or the like is used. be able to. These organic solvents may be used alone or in combination of two or more.

  Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2- Hydroxy-2-methyl-1-propan-1-one, thioxanthone, thioxanthone derivative, 2,2′-dimethoxy-1,2-diphenylethan-1-one, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl phosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- (4 -Morpholinophenyl) -butan-1-one etc. can be used. These photopolymerization initiators may be used alone or in combination of two or more.

  The gel fraction (toluene) of the acrylic pressure-sensitive adhesive is preferably 80% or more, and more preferably in the range of 85 to 93%, from the viewpoint of further improving the stain resistance. In addition, the measuring method of the gel fraction of the said acrylic adhesive is described in the Example mentioned later.

  The urethane adhesive layer (iii) is formed of a urethane adhesive containing a urethane resin.

  As the urethane adhesive, it is preferable to use one that can form a crosslinked structure, in order to achieve good adhesion and wettability at a high level, and specifically, a urethane resin having two or more hydroxyl groups ( It is preferable to use one containing A-1) and a crosslinking agent (A-2). Moreover, it is preferable to further contain a carbodiimide compound (A-3) from the point which can capture | acquire the decomposed material derived from the said polyethylene-terephthalate base material (i), and can improve stain resistance further.

  The said urethane resin (A-1) is obtained by making a polyol (A-1-1) and polyisocyanate (A-1-2) react.

  As said polyol (A-1-1), a polyether polyol, polyester polyol, a polycarbonate polyol, a polybutadiene polyol etc. can be used, for example. These polyols may be used alone or in combination of two or more.

  The number average molecular weight of the polyol (A-1-1) is preferably in the range of 500 to 5,000, and more preferably in the range of 800 to 3,000, from the viewpoint of obtaining good adhesion. preferable. The number average molecular weight of the polyol (A-1-1) is a value measured in the same manner as the weight average molecular weight of the (meth) acrylic resin (X-1).

  If necessary, a chain extender having a number average molecular weight of 50 to 400 may be used in combination with the polyol (A-1-1).

  Examples of the chain extender include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, and 1,3-butanediol. 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 3 -Methyl-1,5-pentanediol, 2-butyl-2-ethylpropanoldiol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like can be used. These chain extenders may be used alone or in combination of two or more.

  Examples of the polyisocyanate (A-1-2) include aromatic polyisocyanates such as xylylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate and naphthalene diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, Aliphatic or alicyclic polyisocyanates such as 4,4'-dicyclohexylmethane diisocyanate, diisocyanate methyl cyclohexane, tetramethyl xylylene diisocyanate and the like can be used. These polyisocyanates may be used alone or in combination of two or more.

  As a manufacturing method of the said urethane resin (A-1), the molar ratio of the hydroxyl group which the said polyol (A-1-1) has with respect to the molar ratio of the isocyanate group which polyisocyanate (A-1-2) has, for example The reaction is carried out so as to be in excess. The reaction may be carried out in an organic solvent described later. As the molar ratio (NCO / OH) of the hydroxyl group of the polyol (A-1-1) to the isocyanate group of the polyisocyanate (A-1-2), ease of reactivity control and crosslinking agent (NCO / OH) The range of 0.3 to 0.99 is preferable, and the range of 0.4 to 0.9 is more preferable, from the viewpoint that adhesion can be further improved by good crosslinkability with A-2). That is, the urethane resin (A-1) is preferably one having two or more hydroxyl groups, and more preferably one having two to four hydroxyl groups. After the production of the urethane resin (A-1), an alcohol solvent such as methanol or 1,3-butanediol may be added for the purpose of deactivating the remaining isocyanate group.

  The weight average molecular weight of the urethane resin (A-1) is preferably in the range of 50,000 to 200,000, from the viewpoint of achieving high levels of adhesion and wettability, and is preferably 70,000 to 150, A range of 000 is more preferred. In addition, the weight average molecular weight of the said urethane resin (A-1) shows the value obtained by measuring similarly to the weight average molecular weight of said (meth) acrylic resin (X-1).

  As said crosslinking agent (A-2), a polyisocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent etc. can be used, for example. These crosslinking agents may be used alone or in combination of two or more. Among these, it is preferable to use an isocyanate crosslinking agent from the viewpoint of obtaining good adhesion and wettability.

  As said polyisocyanate crosslinking agent, the thing similar to the polyisocyanate crosslinking agent which can be used by the above-mentioned crosslinking agent (X-2) can be used.

  The amount of the crosslinking agent (A-2) used is in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the urethane resin (A-1) from the viewpoint of adhesion and wettability. Preferably, the range of 0.1 to 5 parts by mass is more preferable.

  As said carbodiimide compound (A-3), for example, "Carbodilite V-02", "Carbodilite V-02-L2", "Carbodilite V-04", "Carbodilite V-05", "Carbodilite E-01" " Carbodilight E-02 "," Carbodilight E-03A "," Carbodilight E-04 "(all manufactured by Nisshinbo Chemical Co., Ltd.) and the like can be used. These compounds may be used alone or in combination of two or more.

  The amount of the carbodiimide compound (A-3) used is 0 with respect to 100 parts by mass of the urethane resin (A-1) in that good stain resistance can be obtained without reducing the adhesive strength and the wettability. It is preferable that it is the range of .005-5 mass parts, and the range of 0.01-3 mass parts is more preferable.

  As the urethane adhesive, other additives can be used as needed.

  Examples of the other additives include an antioxidant (A-4), a plasticizer (A-5), an organic solvent, an antirust agent, a thixotropic agent, a dispersant, a sensitizer, a urethanization catalyst, and polymerization. Inhibitors, leveling agents, tackifiers, foam stabilizers and the like can be used. These additives may be used alone or in combination of two or more. Among these, it is preferable to use the antioxidant (A-4) because the bleeding of the urethane adhesive itself can be suppressed and the stain resistance can be further reduced. Moreover, it is preferable to use a plasticizer (A-5) from the point which can reduce the surface tension of a urethane adhesive coating film, and can improve a wettability further.

Examples of the antioxidant (A-4) include triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, thiodiethylene bis [3- (3,5-di- tert-Butyl-4-hydroxyphenyl) propionate], benzenepropanoic acid-3,5-bis (1,1-dimethylethyl) -4-hydroxy-C ₇ -C ₉ side chain alkyl ester, 4,6-bis ( Dodecylthiomethyl) -o-cresol, N-phenylbenzenamine and 2,4,4-trimethylpentene Reaction product, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 3,9-bis [2- [3- (t-butyl) -4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro [5.5] undecane, 2,6-di-tert-butyl-4 Hindered phenol compounds such as -methylphenol, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,5-di-tert-amyl hydroquinone and the like; triphenylphosphine, bis (2,4-diphenol) -Tert-butyl-6-methylphenyl) = ethyl = phosphite, triphenyl phosphite, tris nonylphenyl phosphite, tris (2 4-dibutylphenyl) phosphite, tris (2,4-dibutyl-5-methylphenyl) phosphite, tris [2-tert-butyl-4- (3-butyl-4-hydroxy-5-methylphenylthio)- 5-methylphenyl] phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, di (tridecyl) pentaerythritol di- Phosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-dibutylphenyl) pentaerythritol diphosphite, bis (2,6-dibutyl-4-methylphenyl) pentaerythritol diphosphite, bis (bis (2,6-dibutyl-4-methylphenyl) pentaerythritol diphosphite) 2,4,6-Tributylphenyl) pen Taerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidene diphenol diphosphite, tetra (tridecyl) -4,4'-n-butylidene bis (2- Butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1,1,3-tris (2-methyl-4-hydroxy-5-butylphenyl) butane triphosphite, tetrakis (2,4-dibutylphenyl) biphenylene di Phosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis (4,6-butylphenyl) -2-ethylhexyl phosphite, 2,2 ' -Methylenebis (4,6-butylphenyl) -octadeci Phosphite, 2,2′-ethylidene bis (4,6-dibutylphenyl) fluorophosphite, tris (2-[(2,4,8,10-tetrakisbutyldibenzo [d, f] [1,3,2 Phosphorus compounds such as phosphites of dioxaphosphepin-6-yl) oxy] ethyl) amine, 2-ethyl-2-butylpropylene glycol and 2,4,6-tributylphenol; didodecyl-3,3'- Thiopropionate, dilauryl-3,3'-thiodipropionate, laurylylthiodithionate, ditridecyl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl- 3,3'-thiodipropionate, tetrakis-methylene-3-laurylthiopropionate methane, distearyl-3,3'-methyl 3,3'-thiodipropionate, lauryl stearyl-3,3'-thiodipropionate, bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide, Sulfur compounds such as β-laurylthiopropionate, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, dioctadecyl-3,3′-thiodiprothionate; bis (1,2,2,6 6,6-Pentamethyl-4-piperidyl) sebacate, cyclohexane and N-butyl 2,2,6,6-tetramethyl-4-piperidinamine peroxide-2,4,6-trichloro1,3,5-triazine Reaction product of reaction product with 2-aminoethanol, bis (2,2,6,6-tetramethyl-1- (octyl) decanedioate Oxy) -4-piperidinyl) ester, reaction product of 1,1-dimethylethyl hydroperoxide and octane, N-acetyl-3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidinyl) Pyrrolidine-2,5-dione, bis (1,2,2,6,6-pentamethyl-4-piperidyl) = decanedioate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) {[3,5-Bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl} butyl malonate, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6, 6-Tetramethylpiperidine polycondensate, propanedioic acid [{4-methoxyphenyl} methylene] -bis (1,2,2,6,6-pentamethyl-4-piperi) Or the like can be used hindered amine compound in Le) ester. These antioxidants may be used alone or in combination of two or more.

  The amount of the antioxidant (A-4) used is in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the urethane resin (A-1) from the viewpoint of further improving the contamination resistance. Is preferable, and the range of 1 to 7 parts by mass is more preferable.

  As the plasticizer (A-5), for example, an ester compound, diisononyl adipate, bis (2-ethylhexyl) adipate, isopropyl palmitate, isopropyl myristate and the like can be used. These plasticizers may be used alone or in combination of two or more.

  The amount of the plasticizer (A-5) used is preferably in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the urethane resin (A-1) from the viewpoint of further improving the wettability. The range of 10 to 40 parts by mass is more preferable.

  Examples of the organic solvent include ester solvents such as ethyl acetate, methyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as heptane, hexane, cyclohexane and methyl cyclohexane; toluene Aromatic hydrocarbon solvents such as o-xylene, m-xylene, p-xylene and the like can be used. These organic solvents may be used alone or in combination of two or more.

  Next, the manufacturing method of the adhesive film of this invention is demonstrated.

  As a method for producing the pressure-sensitive adhesive film, for example, the acrylic pressure-sensitive adhesive is coated on a polyethylene terephthalate substrate (i) and dried to form an acrylic pressure-sensitive adhesive layer (ii), and then it is formed thereon A method of forming a urethane pressure-sensitive adhesive layer (iii) by applying a urethane pressure-sensitive adhesive and drying the same; coating the acrylic pressure-sensitive adhesive on a polyethylene terephthalate substrate (i) and drying it; A layer (ii) is formed, the urethane pressure-sensitive adhesive is separately coated on a release paper and dried to form a urethane pressure-sensitive adhesive layer (iii), and the acrylic pressure-sensitive adhesive layer (ii) and the urethane The method etc. which bond together an adhesive layer (iii) is mentioned.

  As a method of coating the said acrylic adhesive and the said urethane adhesive, the method of using an applicator, a roll coater, a gravure coater, a reverse coater, a spray coater, an air knife coater, a die coater etc. is mentioned, for example.

  As a method of drying the said acrylic adhesive and the said urethane adhesive, the method of making it dry at 50-120 degreeC for 30 seconds-10 minutes is mentioned, for example. In addition, after producing the adhesive film, further aging may be performed in the range of 30 ° C. to 50 ° C. to accelerate the curing.

  The pressure-sensitive adhesive film of the present invention obtained by the above-described method is excellent in coating property and less in the contamination of the adherend even in a moist and heat resistant environment. The pressure-sensitive adhesive film of the present invention can be particularly suitably used as a surface protective film.

  Hereinafter, the present invention will be described in more detail using examples.

Synthesis Example 1
<Synthesis of Acrylic Adhesive (1)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen introduction pipe, and a thermometer, 89.7 parts by mass of 2-ethylhexyl acrylate (hereinafter abbreviated as "2EHA"), acrylic acid (hereinafter "AA") Abbreviated) 0.2 parts by mass, 10.1 parts by mass of 4-hydroxybutyl acrylate (hereinafter abbreviated as “4HBA”), 0.05 parts by mass of azobisisobutyronitrile, 73 parts by mass of ethyl acetate Then, 25 parts by mass of methyl ethyl ketone was charged, and the mixture was stirred at 72 ° C. for 10 hours while blowing in nitrogen. Cool down after the reaction and add 23 parts by mass of ethyl acetate. The contents were cooled and filtered through a 200-mesh wire mesh to obtain an acrylic resin having a nonvolatile content of 45% by mass, a viscosity of 2,000 mPa · s, and a weight average molecular weight of 300,000. Immediately before producing the adhesive film, 4 parts by mass of hexamethylene diisocyanate trimethylolpropane adduct (containing "Duranate P103-75E" manufactured by Asahi Kasei Co., Ltd., 25% by mass of ethyl acetate solution) as a crosslinking agent is added, followed by acrylic adhesion It is referred to as agent (1).

Synthesis Example 2
<Synthesis of Urethane Adhesive (1)>
A reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen introduction pipe, and a thermometer: 330 parts by mass of polyester polyol-1 ("Kuraray polyol P1010" manufactured by Kuraray Co., Ltd., number average molecular weight; 1,000), hexamethylene diisocyanate (below 100 parts by mass of "HDI", 0.004 parts by mass of dioctyltin dilaurate, and 433 parts by mass of ethyl acetate were charged in a separable flask and heated to 70.degree. After confirming that the isocyanate group content became the content calculated from the preparation amount by a titration method with dibutylamine and hydrochloric acid, the content was cooled to 40 ° C. 960 parts by mass of polyether triol-1 ("Sannicks GL-3000" manufactured by Sanyo Chemical Industries, Ltd., number average molecular weight: 3,000), 0.02 parts by mass of dioctyltin dilaurate, 317 parts by mass of ethyl acetate Charge into a bull flask and heat at 70 ° C. After completion of the reaction was confirmed by the titration method described above, the reaction was cooled. Here, 417 parts by mass of isopropyl myristate, 27.8 parts by mass of antioxidant "tinuvin 765" manufactured by BASF Japan Ltd., and 27.8 parts by mass of Irganox 1010, carbodiimide compound "carbodiimide light V-05 manufactured by Nisshinbo Co., Ltd." And 1 part by mass of ethyl acetate and 250 parts by mass of ethyl acetate were stirred until uniform, and a urethane resin having a nonvolatile content of 65% by mass, a viscosity of 5,000 mPa · s and a weight average molecular weight of 130,000 was obtained. . To this, 5 parts by mass of hexamethylene diisocyanate trimethylolpropane adduct (containing "Duranate P103-75E" manufactured by Asahi Kasei Co., Ltd., containing 25% by mass of ethyl acetate solution) as a crosslinking agent is added as a crosslinking agent, and a urethane adhesive is prepared. (1).

Synthesis Example 3
<Synthesis of Urethane Adhesive (2)>
A reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen introduction pipe, and a thermometer: 298 parts by mass of polyether polyol-1 ("Exenol 1020" manufactured by Asahi Glass Co., Ltd .; number average molecular weight; 1,000); 100 parts by mass of XDI 0.2 parts by mass of dioctyltin dilaurate and 398 parts by mass of ethyl acetate were charged into a separable flask and heated to 75.degree. After confirming that the isocyanate group content became the content calculated from the preparation amount by a titration method with dibutylamine and hydrochloric acid, the content was cooled to 40 ° C. 1,397 parts by mass of polyether triol-2 ("EXENOL 3030" manufactured by Asahi Glass Co., Ltd., number average molecular weight: 3,000) and 569 parts by mass of ethyl acetate were charged in a separable flask and heated at 70 ° C. After confirming that the isocyanate group content rate became the content rate calculated from the preparation amount by the above-mentioned titration method, it was cooled to 60 ° C. Next, 30 parts by mass of XDI and 16 parts by mass of ethyl acetate were charged, and the mixture was heated at 70 ° C. Confirm the end of the reaction by the titration method described above and cool it. Here, 547 parts by mass of "Monociser W260" manufactured by DIC Corporation, 36.5 parts by mass of tinuvin 765, 36.5 parts by mass of Irganox 1010, 18.2 parts by mass of Carbodilite V-05, 326 parts by mass of ethyl acetate The mixture was stirred until it became uniform, to obtain a urethane resin having a nonvolatile content of 65% by mass, a viscosity of 2,000 mPa · s, and a weight average molecular weight of 80,000. Immediately before producing the adhesive film, 5 parts by mass of hexamethylene diisocyanate trimethylolpropane adduct (containing "Duranate P103-75E" manufactured by Asahi Kasei Co., Ltd., 25% by mass of ethyl acetate solution) is added as a crosslinking agent, and urethane adhesion is performed. Agent (2).

Example 1
The acrylic adhesive (1) is applied to the surface of a 50 μm thick polyethylene terephthalate substrate (hereinafter abbreviated as “PET”) so that the film thickness after drying is 5 μm, and it is maintained at 80 ° C. for 3 minutes It was allowed to dry. Next, the urethane adhesive (1) is applied to the surface of a 38 μm-thick release-treated polyethylene terephthalate substrate (hereinafter, “release PET 38”) so that the film thickness after drying is 5 μm, and 80 Dried for 3 minutes at ° C. The formed pressure-sensitive adhesive layers were bonded to each other, and aged at 40 ° C. for 3 days to obtain a pressure-sensitive adhesive film.

Example 2
An adhesive film was obtained in the same manner as in Example 1 except that the types of the acrylic adhesive and urethane adhesive to be used and the thickness thereof were changed as shown in Table 1.

Comparative Example 1
The urethane pressure-sensitive adhesive (1) was applied to the surface of a 50 μm-thick PET so that the film thickness after drying was 10 μm, and dried at 80 ° C. for 3 hours. Thereafter, it was aged at 40 ° C. for 3 days to obtain an adhesive film.

Comparative Examples 2 and 3
An adhesive film was obtained in the same manner as in Comparative Example 1 except that the type of adhesive was changed as shown in Table 1.

[Method of measuring gel fraction]
(Gel fraction of whole adhesive layer of adhesive film)
The adhesive films obtained in Examples and Comparative Examples were cut into a width of 25 mm and a length of 80 mm, and those from which the release PET 38 was peeled off were used as test pieces. The test piece was placed in a sample bottle containing toluene and left at 23 ° C. for 24 hours. Thus, the gel fraction was calculated using the following formula (1).
Gel fraction (%) = (Test specimen mass after toluene immersion-Non-woven fabric mass-PET mass) / Test specimen mass before toluene immersion (1)
(Gel fraction of acrylic adhesive layer (ii))
The acrylic pressure-sensitive adhesive (1) is applied to the surface of a 50 μm-thick polyethylene terephthalate substrate so that the film thickness after drying is 5 μm, and the acrylic pressure-sensitive adhesive obtained in Synthesis Example is applied for 3 hours at 80 ° C. It dried and obtained the laminated body. What cut this into width 25 mm and length 80 mm was made into the test piece. After that, the gel fraction of the acrylic pressure-sensitive adhesive layer (ii) was calculated in the same manner as (the gel fraction of the pressure-sensitive adhesive film).

[Method of measuring adhesion]
The pressure-sensitive adhesive films obtained in Examples and Comparative Examples were cut to a width of 20 mm, and those from which release PET 38 was peeled off were used as test pieces. This was pasted twice with a 2 kg roll so that an adhesion area might be 20 mm x 60 mm with respect to a glass plate. Peeling strength was applied 180 degrees in an atmosphere of 23 ° C. and 50% humidity 24 hours after pasting to obtain adhesive strength (N / 25 mm). After the application, the film is left for 72 hours at 85 ° C. and 85% humidity, and then left for 24 hours in a 23 ° C. environment. 25 mm).

[Method for evaluating contamination resistance]
Release PET of the adhesive film obtained by the Example and the comparative example was peeled, and it affixed on the glass plate. At that time, air bubbles were introduced between the adhesive film and the glass plate. The test sample was left for 72 hours at 85 ° C. and 85% humidity. Thereafter, the adhesive film was peeled off from the glass plate by hand after standing for 24 hours under an environment of 23 ° C., the LED light was irradiated from the lower part of the glass plate, and the contamination state was visually observed and evaluated as follows.
"T": There is no contamination on the glass plate, or only partial contamination on the glass plate is confirmed.
"F": Contamination is confirmed on the entire surface of the glass plate.

[Method of evaluating wettability]
The adhesive films obtained in Examples and Comparative Examples were cut into rectangles of 5 cm in width and 15 cm in length, and those from which release PET was peeled were used as test pieces. After holding both ends of this test piece by hand, bending it, bonding the center of the exposed adhesive layer to the glass plate, releasing the hand and measuring the number of seconds until the adhesive film is attached to the glass plate by its own weight .

  The pressure-sensitive adhesive film of the present invention was found to be excellent in wettability and stain resistance.

  On the other hand, Comparative Examples 1 and 2 are adhesive films of only the urethane adhesive layer as the adhesive layer, but the contamination resistance was extremely poor. Moreover, although the comparative example 3 is an adhesive film of only an acrylic adhesive layer as an adhesive layer, the wettability was extremely bad.

Claims (6)

The polyethylene terephthalate substrate (i), the acrylic pressure-sensitive adhesive layer (ii), and the urethane pressure-sensitive adhesive layer (iii) are sequentially laminated ,
The urethane resin constituting the urethane pressure-sensitive adhesive layer (iii) contains a urethane resin (A-1) having two or more hydroxyl groups, a crosslinking agent (A-2), and a carbodiimide compound (A-3) adhesive film, wherein the at. The pressure-sensitive adhesive film according to claim 1, wherein the total of the thickness of the acrylic pressure-sensitive adhesive layer (ii) and the thickness of the urethane pressure-sensitive adhesive layer (iii) is in the range of 5 to 50 μm. The acrylic pressure-sensitive adhesive layer (ii) and the ratio of the thickness of the urethane adhesive layer (iii) [(ii) / (iii)], according to claim 1 or 2, wherein in the range of 15/85 to 60/40 Adhesive film. The pressure-sensitive adhesive film according to any one of claims 1 to 3, wherein the weight average molecular weight of the urethane resin (A-1) is in the range of 50,000 to 200,000. The pressure-sensitive adhesive film according to any one of claims 1 to 4, wherein the urethane pressure-sensitive adhesive further contains an antioxidant (A-4). The adhesive film according to any one of claims 1 to 5 , which is for surface protection.