JP2015131886A - Urethane adhesive and surface protective film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a urethane adhesive which can sufficiently inhibit whitening of an adherend and has excellent reworkability, provide a surface protection film with such a urethane adhesive used as an adhesive layer, wherein the surface protection film can sufficiently inhibit whitening of the adherend and has excellent reworkability, and provide an optical member and an electronic member with such a surface protection film stuck thereto.SOLUTION: A urethane adhesive of the invention is a urethane adhesive that comprises a polyurethane resin. The polyurethane resin is a polyurethane resin obtained by curing a composition comprising a polyol (A), a polyfunctional isocyanate compound (B) and a catalyst (C). The catalyst (C) is a catalyst that satisfies a molar ratio (Sn catalyst/Fe catalyst)≤0.3.

Description

  The present invention relates to a urethane-based pressure-sensitive adhesive. The present invention also relates to a surface protective film using such a urethane-based adhesive. The surface protective film of this invention has a base material layer and an adhesive layer, for example, is preferably used for the use which affixes on the surface of an optical member or an electronic member, and protects this surface. The present invention further relates to an optical member and an electronic member to which the surface protective film of the present invention is thus attached.

  LCDs, organic EL, touch panels using these, lens parts of cameras, optical members and electronic members such as electronic devices are generally exposed to prevent scratches on the surface during processing, assembly, inspection, transportation, etc. A surface protective film is attached to the surface side. Such a surface protective film is peeled off from the optical member or the electronic member when the surface protection is no longer necessary.

  In many cases, such surface protection films continue to use the same surface protection film from the manufacturing process of optical members and electronic members, through the assembly process, inspection process, transportation process, etc. until final shipment. Yes. In this case, such a surface protective film is often attached, peeled off and reattached manually in each step.

  When the surface protective film is attached manually, air bubbles may be caught between the adherend and the surface protective film. For this reason, some techniques which improve the wettability of a surface protection film are reported so that a bubble may not be involved in the case of sticking. For example, a surface protective film using a silicone resin having a high wetting speed as an adhesive layer is known. However, when silicone resin is used for the pressure-sensitive adhesive layer, the pressure-sensitive adhesive component easily contaminates the adherend, and surface protection for protecting the surface of members that require particularly low contamination such as optical members and electronic members. There is a problem in using it as a film.

  As a surface protective film with little contamination derived from the pressure-sensitive adhesive component, a surface protective film using an acrylic resin for the pressure-sensitive adhesive layer is known. However, the surface protective film using acrylic resin for the adhesive layer is inferior in wettability, so when sticking the surface protective film manually, air bubbles are involved between the adherend and the surface protective film. There is. In addition, when an acrylic resin is used for the adhesive layer, there is a problem that glue residue is likely to be generated at the time of peeling, and a surface protection film for protecting the surface of a member that is particularly apt to be mixed with foreign substances such as an optical member and an electronic member. There is a problem to use as.

  As a surface protective film excellent in wettability, a surface protective film using a urethane-based pressure-sensitive adhesive in a pressure-sensitive adhesive layer has been reported (for example, see Patent Document 1).

  However, when a surface protective film using a conventional urethane pressure-sensitive adhesive for the pressure-sensitive adhesive layer is attached to the adherend and then peeled off, there is a problem that the adherend tends to be whitened.

  Moreover, when sticking a surface protection film to a to-be-adhered body by hand, it is requested | required that it is excellent in wettability, and light peelability is requested | required. This is because the surface protective film attached to the adherend may be reattached to the adherend after being peeled and used again as a surface protective film. Even if the wettability is excellent, if the peeling is heavy, when the surface protective film is peeled off, the surface protective film is deformed and cannot be used again as the surface protective film. In order to avoid such problems, the surface protective film used for optical members and electronic members can be stuck many times without entrainment of bubbles, and can be peeled lightly without deformation, so-called reworkability is strong. Desired. However, the conventional urethane-based pressure-sensitive adhesive has a high increase in adhesive strength over time, and in the surface protective film using such a conventional urethane-based pressure-sensitive adhesive for the pressure-sensitive adhesive layer, it is attached to the adherend. However, if it continues for a long time, heavy peeling occurs and there is a problem that reworkability is poor.

JP 2006-18295 A

  The subject of this invention is providing the urethane type adhesive which can fully suppress the whitening of a to-be-adhered body, and was excellent in rework property. Another object of the present invention is to provide a surface protective film using such a urethane-based pressure-sensitive adhesive for the pressure-sensitive adhesive layer, which can sufficiently suppress whitening of the adherend and has excellent reworkability. There is to do. Moreover, the subject of this invention is providing the optical member and electronic member by which such a surface protection film was stuck.

The urethane adhesive of the present invention is
A urethane-based adhesive containing a polyurethane-based resin,
The polyurethane resin is a polyurethane resin obtained by curing a composition containing a polyol (A), a polyfunctional isocyanate compound (B) and a catalyst (C),
The catalyst (C) is a catalyst system satisfying (Sn-based catalyst / Fe-based catalyst) ≦ 0.3 in molar ratio.

  In preferable embodiment, the content rate of the said catalyst (C) with respect to the said polyol (A) is 0.0005 weight%-0.5 weight%.

  In a preferred embodiment, the polyol (A) is two or more kinds of polyols.

  In a preferred embodiment, the polyol (A) is a polyol having a number average molecular weight Mn of 400 to 20000.

  In a preferred embodiment, the polyol (A) is a polyether polyol.

  In preferable embodiment, the content rate of the said polyfunctional isocyanate compound (B) with respect to the said polyol (A) is 5 to 60 weight%.

The surface protective film of the present invention is
Having a base material layer and an adhesive layer,
The pressure-sensitive adhesive layer contains the urethane pressure-sensitive adhesive of the present invention.

  The optical member of the present invention has the surface protective film of the present invention attached thereto.

  The electronic member of the present invention is obtained by attaching the surface protective film of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the urethane type adhesive which can fully suppress the whitening of a to-be-adhered body and was excellent in rework property can be provided. Further, according to the present invention, there is provided a surface protective film using such a urethane-based pressure-sensitive adhesive for the pressure-sensitive adhesive layer, which can sufficiently suppress whitening of the adherend and has excellent reworkability. can do. Moreover, according to this invention, the optical member and electronic member to which such a surface protection film was stuck can be provided.

It is a schematic sectional drawing of the surface protection film by preferable embodiment of this invention.

≪A. Urethane adhesive >>
The urethane-based pressure-sensitive adhesive of the present invention contains a polyurethane-based resin.

  The content ratio of the polyurethane resin in the urethane-based pressure-sensitive adhesive of the present invention is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and still more preferably 90% by weight to 100% by weight. % By weight, particularly preferably 95% by weight to 100% by weight, and most preferably 98% by weight to 100% by weight. To provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of an adherend and has excellent reworkability by adjusting the content ratio of the polyurethane-based resin in the urethane-based pressure-sensitive adhesive of the present invention within the above range. Can do.

  The polyurethane-based resin is a polyurethane-based resin obtained by curing a composition containing a polyol (A), a polyfunctional isocyanate compound (B), and a catalyst (C).

  As long as the polyol (A) is a polyol having two or more OH groups, any appropriate polyol can be adopted as long as the effects of the present invention are not impaired.

  Only one type of polyol (A) may be used, or two or more types may be used. In order to express the effect of the present invention more preferably, the polyol (A) is preferably two or more kinds of polyols. When the polyol (A) is two or more kinds of polyols, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability.

  The number average molecular weight Mn of the polyol (A) is preferably 400-20000. When the number average molecular weight Mn of the polyol (A) is within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability.

  The polyol (A) preferably contains a polyol (A1) having three OH groups and a number average molecular weight Mn of 8000 to 20000. Only one type of polyol (A1) may be used, or two or more types may be used.

  The content ratio of the polyol (A1) in the polyol (A) is preferably 70% by weight or more, more preferably 70% by weight to 100% by weight, still more preferably 70% by weight to 90% by weight, Particularly preferred is 70 to 80% by weight. By adjusting the content ratio of the polyol (A1) in the polyol (A) within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability. . When the content ratio of the polyol (A1) in the polyol (A) is out of the above range, there is a risk that the time-dependent increase in adhesive strength may be particularly high, and the excellent reworkability may not be exhibited.

  The number average molecular weight Mn of the polyol (A1) is 8000 to 20000, preferably 8000 to 18000, more preferably 8500 to 17000, still more preferably 9000 to 16000, and particularly preferably 9500 to 15500. Most preferably, it is 10000-15000. By adjusting the number average molecular weight Mn of the polyol (A1) within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability.

  The polyol (A) may contain a polyol (A2) having 3 or more OH groups and a number average molecular weight Mn of 5000 or less. Only one type of polyol (A2) may be used, or two or more types may be used. The number average molecular weight Mn of the polyol (A2) is preferably 500 to 5000, more preferably 800 to 4500, still more preferably 1000 to 4000, particularly preferably 1000 to 3500, and most preferably 1000. ~ 3000. By adjusting the number average molecular weight Mn of the polyol (A2) within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability. When the number average molecular weight Mn of the polyol (A2) is out of the above range, the adhesive strength may increase with time, and excellent reworkability may not be exhibited.

  The polyol (A2) preferably has a polyol (triol) having 3 OH groups, a polyol (tetraol) having 4 OH groups, a polyol (pentaol) having 5 OH groups, and 6 OH groups. Polyol (hexaol). As the polyol (A2), a total amount of at least one of a polyol having 4 OH groups (tetraol), a polyol having 5 OH groups (pentaol), and a polyol having 6 OH groups (hexaol) is: The content ratio in the polyol (A) is preferably 10% by weight or less, more preferably 7% by weight or less, still more preferably 6% by weight or less, and particularly preferably 5% by weight or less.

  The content ratio of the polyol (A2) in the polyol (A) is preferably 30% by weight or less, more preferably 0% by weight to 30% by weight. By adjusting the content ratio of the polyol (A2) in the polyol (A) within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability. .

  In the polyol (A2), the content ratio of the polyol having 4 or more OH groups and a number average molecular weight Mn of 5000 or less is preferably less than 10% by weight, more preferably 8% by weight based on the whole polyol (A). % Or less, more preferably 7% by weight or less, particularly preferably 6% by weight or less, and most preferably 5% by weight or less. By adjusting the content ratio of the polyol having 4 or more OH groups in the polyol (A2) having a number average molecular weight Mn of 5000 or less within the above range, whitening of the adherend can be more sufficiently suppressed and reworkability can be achieved. An excellent urethane-based pressure-sensitive adhesive can be provided. When the content ratio of the polyol having 4 or more OH groups in the polyol (A2) having a number average molecular weight Mn of 5000 or less is out of the above range, the urethane pressure-sensitive adhesive of the present invention is easily whitened and has transparency. May decrease.

  Examples of the polyol (A) include polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, castor oil-based polyol, and the like. In the present invention, the polyol (A) is preferably a polyether polyol. In the present invention, when the polyol (A) is a polyether polyol, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability.

  The polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

  Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 2-butyl-2-ethyl-1. , 3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl Examples include -1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol.

  Examples of the acid component include succinic acid, methyl succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-biphenyl dicarboxylic acid, acid anhydrides thereof Etc.

  Examples of polyether polyols include water, low molecular weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcin, hydroquinone, etc.), etc. And polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

  Examples of the polycaprolactone polyol include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

  Examples of the polycarbonate polyol include a polycarbonate polyol obtained by polycondensation reaction of the polyol component and phosgene; the polyol component, dimethyl carbonate, diethyl carbonate, diprovir carbonate, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, ethylene carbonate, Polycarbonate polyol obtained by ester exchange condensation with carbonic acid diesters such as propylene carbonate, diphenyl carbonate and dibenzyl carbonate; copolymerized polycarbonate polyol obtained by using two or more of the above polyol components in combination; Polycarbonate polyol obtained by esterification reaction with a compound; the above-mentioned various polycarbonate polyols and a hydroxyl group-containing compound A polycarbonate polyol obtained by a reaction of tellurization; a polycarbonate polyol obtained by a transesterification reaction between the above various polycarbonate polyols and an ester compound; a polycarbonate polyol obtained by a transesterification reaction between the various polycarbonate polyols and a hydroxyl group-containing compound; And polyester polycarbonate polyols obtained by polycondensation reaction of the various polycarbonate polyols with dicarboxylic acid compounds; copolymer polyether polycarbonate polyols obtained by copolymerizing the various polycarbonate polyols and alkylene oxides;

  An example of the castor oil-based polyol is a castor oil-based polyol obtained by reacting a castor oil fatty acid with the polyol component. Specific examples include castor oil-based polyols obtained by reacting castor oil fatty acid with polypropylene glycol.

  One type of polyfunctional isocyanate compound (B) may be sufficient, and two or more types may be sufficient as it.

  As the polyfunctional isocyanate compound (B), any appropriate polyfunctional isocyanate compound that can be used in the urethanization reaction can be adopted. Examples of such a polyfunctional isocyanate compound (B) include polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanate compounds, polyfunctional aromatic isocyanate compounds, and the like.

  Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4 Examples include 4-trimethylhexamethylene diisocyanate.

  Examples of the polyfunctional alicyclic isocyanate compound include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, Examples include hydrogenated tolylene diisocyanate and hydrogenated tetramethylxylylene diisocyanate.

  Examples of the polyfunctional aromatic diisocyanate compound include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2 ′ monodiphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4. Examples include '-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

  Examples of the polyfunctional isocyanate compound (B) include trimethylolpropane adducts of various polyfunctional isocyanate compounds as described above, burettes reacted with water, and trimers having an isocyanurate ring. These may be used in combination.

  The content ratio of the polyfunctional isocyanate compound (B) is preferably 5% by weight to 60% by weight and more preferably 8% by weight to 60% by weight of the polyfunctional isocyanate compound (B) with respect to the polyol (A). %, More preferably 10% to 60% by weight. By adjusting the content ratio of the polyfunctional isocyanate compound (B) within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability.

  In the polyol (A) and the polyfunctional isocyanate compound (B), the equivalent ratio of the NCO group to the OH group is preferably 1.0 to 5.0, more preferably 1.2 to NCO group / OH group. It is 4.0, More preferably, it is 1.5-3.5, Most preferably, it is 1.8-3.0. By adjusting the equivalent ratio of NCO group / OH group within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability.

  The catalyst (C) is a catalyst system satisfying (Sn-based catalyst / Fe-based catalyst) ≦ 0.3 by molar ratio. By employing such a catalyst (C), it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability. When the catalyst (C) is not a catalyst system satisfying (Sn-based catalyst / Fe-based catalyst) ≦ 0.3 in terms of molar ratio, the urethane-based pressure-sensitive adhesive of the present invention is particularly likely to be whitened.

  The catalyst (C) may include only an Fe-based catalyst or may include both an Sn-based catalyst and an Fe-based catalyst. In any of these cases, the catalyst (C) is a catalyst system that satisfies a specific ratio of (Sn-based catalyst / Fe-based catalyst) ≦ 0.3 in terms of molar ratio, thereby whitening the adherend. It is possible to provide a urethane-based pressure-sensitive adhesive that is more sufficiently suppressed and has excellent reworkability. In the present invention, the catalyst (C) preferably includes both an Sn-based catalyst and an Fe-based catalyst.

  Examples of the Sn-based catalyst include an organometallic compound containing tin. Specific examples include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, and dibutyltin. Examples include diacetate, dibutyltin sulfide, tributyltin methoxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate, etc. .

  There may be only one type of Sn-based catalyst, or two or more types.

  Examples of the Fe-based catalyst include an organometallic compound containing iron, and specific examples include iron acetylacetonate and iron 2-ethylhexanoate.

  Only one Fe-based catalyst may be used, or two or more Fe-based catalysts may be used.

  The amount of the catalyst (C) is preferably 0.0005% by weight to 0.5% by weight, more preferably 0.001% by weight to 0.3% by weight, based on the polyol (A). Preferably they are 0.01 weight%-0.1 weight%, Especially preferably, they are 0.02 weight%-0.08 weight%, Most preferably, they are 0.02 weight%-0.06 weight%. By adjusting the amount of the catalyst (C) within the above range, it is possible to provide a urethane-based pressure-sensitive adhesive that can sufficiently suppress whitening of the adherend and has excellent reworkability.

  The polyurethane-based resin is obtained by curing a composition containing a polyol (A), a polyfunctional isocyanate compound (B), and a catalyst (C). In such a composition, in the range which does not impair the effect of this invention, arbitrary appropriate other components other than a polyol (A), a polyfunctional isocyanate compound (B), and a catalyst (C) may be included. Examples of such other components include other resin components other than polyurethane resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, plasticizers, and anti-aging agents. Agents, conductive agents, antioxidants, ultraviolet absorbers, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, and the like.

  The polyurethane-based resin preferably contains a deterioration inhibitor such as an antioxidant, an ultraviolet absorber, and a light stabilizer. When the polyurethane-based resin contains a deterioration preventing agent, the adhesive residue can be prevented from remaining on the adherend, for example, even when the polyurethane resin is attached to the adherend and stored in a heated state, and thus the adhesive residue hardly occurs on the adherend. There may be only one type of deterioration preventing agent, or two or more types. As the deterioration preventing agent, an antioxidant is particularly preferable.

  The content ratio of the deterioration preventing agent is preferably 0.01% by weight to 10% by weight, more preferably 0.05% by weight to 7% by weight, and still more preferably 0.8% with respect to the polyol (A). It is 1% by weight to 5% by weight, particularly preferably 0.1% by weight to 3% by weight, and most preferably 0.1% by weight to 1% by weight. By adjusting the content ratio of the deterioration preventive agent within the above range, adhesive residue is less likely to remain on the adherend even if it is stored in a heated state after being attached to the adherend. Can become better. If the content ratio of the deterioration inhibitor is too small, there is a possibility that the adhesive residue preventing property cannot be sufficiently exhibited. If the content of the deterioration inhibitor is too large, there may be a problem that the cost is disadvantageous, a problem that the adhesive property cannot be maintained, or a problem that the adherend is contaminated may occur. .

  Examples of the antioxidant include a radical chain inhibitor and a peroxide decomposer.

  Examples of the radical chain inhibitor include phenolic antioxidants and amine antioxidants.

  Examples of the peroxide decomposer include a sulfur-based antioxidant and a phosphorus-based antioxidant.

  Examples of phenolic antioxidants include monophenolic antioxidants, bisphenolic antioxidants, and high-molecular phenolic antioxidants.

  Examples of the monophenol antioxidant include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearin-β- ( 3,5-di-t-butyl-4-hydroxyphenyl) propionate and the like.

  Examples of the bisphenol antioxidant include 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4 ′. -Thiobis (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- ( 3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane.

  Examples of the polymeric phenolic antioxidant include 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4, 6-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane Bis [3,3′-bis- (4′-hydroxy-3′-t-butylphenyl) butyric acid] glycol ester, 1,3,5-tris (3 ′, 5′-di-t-butyl) -4′-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione, tocophenol and the like.

  Examples of the sulfur-based antioxidant include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate.

  Examples of phosphorus antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, and phenyl diisodecyl phosphite.

  Examples of UV absorbers include benzophenone UV absorbers, benzotriazole UV absorbers, salicylic acid UV absorbers, oxalic anilide UV absorbers, cyanoacrylate UV absorbers, and triazine UV absorbers. It is done.

  Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2 ′. -Dihydroxy-4-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenyl) ) Methane.

  Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, 2- ( 2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2 -(2'-hydroxy-3 ', 5'-di-tert-butylphenyl) 5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-di-tert-amylphenyl) benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2- [2′-hydroxy-3 ′-(3 ', 4' ', 5' ', 6' ',-tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2'methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], [2 (2′-hydroxy-5′-methacryloxyphenyl) -2H-benzotriazole, and the like.

  Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

  Examples of the cyanoacrylate-based ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3′-diphenyl acrylate, ethyl-2-cyano-3,3′-diphenyl acrylate, and the like.

  Examples of the light stabilizer include hindered amine light stabilizers and ultraviolet light stabilizers.

  Examples of the hindered amine light stabilizer include [bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate], bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate. Methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate and the like.

  Examples of the ultraviolet stabilizer include nickel bis (octylphenyl) sulfide, [2,2′-thiobis (4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-tert- Examples thereof include butyl-4-hydroxybenzyl-phosphate monoethylate, nickel-dibutyldithiocarbamate, benzoate type quencher, and nickel-dibutyldithiocarbamate.

  The polyurethane-based resin preferably contains a fatty acid ester. When the polyurethane resin contains a fatty acid ester, the wetting speed can be improved. Only one type of fatty acid ester may be used, or two or more types may be used.

  The content ratio of the fatty acid ester is preferably 5% by weight to 50% by weight, more preferably 7% by weight to 40% by weight, and further preferably 8% by weight to 35% by weight with respect to the polyol (A). And particularly preferably 9 to 30% by weight, most preferably 10 to 35% by weight. By adjusting the content ratio of the fatty acid ester within the above range, the wetting rate can be further improved. If the content of the fatty acid ester is too small, the wetting rate may not be sufficiently improved. When the content ratio of the fatty acid ester is too large, there may be a problem that the cost becomes disadvantageous, a problem that the adhesive property cannot be maintained, or a problem that the adherend is contaminated.

  The number average molecular weight Mn of the fatty acid ester is preferably 200 to 400, more preferably 210 to 395, still more preferably 230 to 380, particularly preferably 240 to 360, and most preferably 270 to 340. It is. By adjusting the number average molecular weight Mn of the fatty acid ester within the above range, the wetting rate can be further improved. If the number average molecular weight Mn of the fatty acid ester is too small, the wetting rate may not be improved even if the number of added parts is large. If the number average molecular weight Mn of the fatty acid ester is too large, the curability of the pressure-sensitive adhesive at the time of drying deteriorates, and there is a possibility that it may not only affect the wettability but also adversely affect other adhesive properties.

  As the fatty acid ester, any appropriate fatty acid ester can be adopted as long as the effects of the present invention are not impaired. Examples of such fatty acid esters include polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, monoglyceride behenate, cetyl 2-ethylhexanoate, and myristic acid. Isopropyl, isopropyl palmitate, cholesteryl isostearate, lauryl methacrylate, coconut fatty acid methyl, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate , Pentaerythritol tetrapalmitate, stearyl stearate, isotridecyl stearate, triglyceride 2-ethylhexanoate , Butyl laurate, and the like octyl oleate.

  Examples of a method for obtaining a polyurethane resin by curing a composition containing a polyol (A), a polyfunctional isocyanate compound (B) and a catalyst (C) include a urethanization reaction method using bulk polymerization, solution polymerization, and the like. Any appropriate method can be adopted as long as the effects of the present invention are not impaired.

  The urethane-based pressure-sensitive adhesive of the present invention may contain any appropriate other component within the range not impairing the effects of the present invention, in addition to the polyurethane-based resin as described above. Examples of such other components include other resin components other than polyurethane resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, plasticizers, and anti-aging agents. Agents, conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents and the like.

  In the urethane-based pressure-sensitive adhesive of the present invention, the adhesive strength to the glass plate is preferably 0.5 N / 25 mm or less, more preferably 0.005 N / 25 mm to 0 as the initial adhesive force immediately after sticking to the glass plate. 0.5 N / 25 mm, more preferably 0.005 N / 25 mm to 0.4 N / 25 mm, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, and most preferably 0.01 N / 25 mm to 0.2 N / 25 mm. When the initial adhesive force is within the above range, the urethane pressure-sensitive adhesive of the present invention has appropriate initial adhesiveness and can exhibit further excellent reworkability. The measurement of the initial adhesive strength will be described later.

  The urethane-based pressure-sensitive adhesive of the present invention has an adhesive strength to a glass plate of 50 N.times.7 days after being adhered to the glass plate, preferably 0.5 N / 25 mm or less, more preferably 0.005 N / 25 mm to 0.5 N / 25 mm, more preferably 0.005 N / 25 mm to 0.4 N / 25 mm, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, most preferably 0.01 N / 25 mm. It is -0.2N / 25mm. When the pressure-sensitive adhesive strength is within the above range, the urethane-based pressure-sensitive adhesive of the present invention can exhibit further excellent reworkability. The measurement of the adhesive strength will be described later.

  The urethane-based pressure-sensitive adhesive of the present invention has an adhesive force to a glass plate of preferably 0.5 N / 25 mm or less after 60 ° C. × 90% RH × 7 days after sticking to the glass plate, more preferably 0. 005N / 25mm to 0.5N / 25mm, more preferably 0.005N / 25mm to 0.4N / 25mm, particularly preferably 0.005N / 25mm to 0.3N / 25mm, most preferably 0. .01N / 25mm to 0.2N / 25mm. When the pressure-sensitive adhesive strength is within the above range, the urethane-based pressure-sensitive adhesive of the present invention can exhibit further excellent reworkability. The measurement of the adhesive strength will be described later.

  The urethane-based pressure-sensitive adhesive of the present invention has an adhesive strength to a glass plate of 85 N ° C x 7 days after sticking to the glass plate, preferably 0.5 N / 25 mm or less, more preferably 0.005 N / 25 mm to 0.5 N / 25 mm, more preferably 0.005 N / 25 mm to 0.4 N / 25 mm, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, most preferably 0.01 N / 25 mm. It is -0.2N / 25mm. When the pressure-sensitive adhesive strength is within the above range, the urethane-based pressure-sensitive adhesive of the present invention can exhibit further excellent reworkability. The measurement of the adhesive strength will be described later.

  The urethane-based pressure-sensitive adhesive of the present invention has an adhesive force to a glass plate immediately after sticking to the glass plate, after sticking to the glass plate, 50 ° C. × 7 days, 60 ° C. × 90% RH × 7 days, 85 ° C. × In any case after 7 days, it is preferably 0.5 N / 25 mm or less, more preferably 0.005 N / 25 mm to 0.5 N / 25 mm, and still more preferably 0.005 N / 25 mm to 0.4 N / 25 mm. Yes, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, and most preferably 0.01 N / 25 mm to 0.2 N / 25 mm. When the pressure-sensitive adhesive strength is within the above range, the urethane-based pressure-sensitive adhesive of the present invention can exhibit further excellent reworkability.

  The urethane pressure-sensitive adhesive of the present invention preferably has high transparency. Due to the high transparency of the urethane-based pressure-sensitive adhesive of the present invention, it becomes possible to accurately inspect the surface of the optical member or the electronic member while it is adhered. The urethane-based pressure-sensitive adhesive of the present invention has a haze of preferably 5% or less, more preferably 4% or less, still more preferably 3% or less, particularly preferably 2% or less, and most preferably 1% or less.

≪B. Surface protection film >>
The surface protective film of this invention is a surface protective film preferably used for the surface protection of an optical member or an electronic member. The surface protective film of this invention has a base material layer and an adhesive layer, and this adhesive layer contains the urethane type adhesive of this invention.

  FIG. 1 is a schematic cross-sectional view of a surface protective film according to a preferred embodiment of the present invention. The surface protective film 10 includes a base material layer 1 and an adhesive layer 2. The surface protective film of the present invention may further have any appropriate other layer as required (not shown).

  For the purpose of forming a wound body that can be easily rewound on the surface of the base material layer 1 that is not provided with the pressure-sensitive adhesive layer 2, for example, the base material layer includes a fatty acid amide, polyethyleneimine, and a long-chain alkyl series. A release treatment can be performed by adding an additive or the like, or a coating layer made of any appropriate release agent such as silicone, long-chain alkyl, or fluorine can be provided.

  The surface protective film of the present invention may be bonded with a release liner having releasability.

  The thickness of the surface protective film of the present invention can be set to any appropriate thickness depending on the application. From the viewpoint of sufficiently expressing the effects of the present invention, the thickness is preferably 10 μm to 300 μm, more preferably 15 μm to 250 μm, still more preferably 20 μm to 200 μm, and particularly preferably 25 μm to 150 μm.

  In the surface protective film of the present invention, the adhesive strength of the pressure-sensitive adhesive layer to the glass plate is preferably 0.5 N / 25 mm or less, more preferably 0.005 N / as the initial adhesive strength immediately after being attached to the glass plate. 25 mm to 0.5 N / 25 mm, more preferably 0.005 N / 25 mm to 0.4 N / 25 mm, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, most preferably 0.01 N. / 25 mm to 0.2 N / 25 mm. When the initial adhesive strength is within the above range, the surface protective film of the present invention has appropriate initial adhesiveness and can exhibit more excellent reworkability. The measurement of the initial adhesive strength will be described later.

  In the surface protective film of the present invention, the adhesive strength of the pressure-sensitive adhesive layer to the glass plate is preferably 0.5 N / 25 mm or less, more preferably 0.005 N, after 50 ° C. × 7 days after sticking to the glass plate. / 25 mm to 0.5 N / 25 mm, more preferably 0.005 N / 25 mm to 0.4 N / 25 mm, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, and most preferably 0.8. The range is 01 N / 25 mm to 0.2 N / 25 mm. When the adhesive strength is within the above range, the surface protective film of the present invention can exhibit more excellent reworkability. The measurement of the adhesive strength will be described later.

  In the surface protective film of the present invention, the adhesive strength of the pressure-sensitive adhesive layer to the glass plate is preferably 0.5 N / 25 mm or less after 60 ° C. × 90% RH × 7 days after being adhered to the glass plate, more preferably. Is 0.005 N / 25 mm to 0.5 N / 25 mm, more preferably 0.005 N / 25 mm to 0.4 N / 25 mm, and particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm. Preferably they are 0.01N / 25mm-0.2N / 25mm. When the adhesive strength is within the above range, the surface protective film of the present invention can exhibit more excellent reworkability. The measurement of the adhesive strength will be described later.

  In the surface protective film of the present invention, the adhesive strength of the pressure-sensitive adhesive layer to the glass plate is preferably 0.5 N / 25 mm or less, more preferably 0.005 N, after 85 ° C. × 7 days after sticking to the glass plate. / 25 mm to 0.5 N / 25 mm, more preferably 0.005 N / 25 mm to 0.4 N / 25 mm, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, and most preferably 0.8. The range is 01 N / 25 mm to 0.2 N / 25 mm. When the adhesive strength is within the above range, the surface protective film of the present invention can exhibit more excellent reworkability. The measurement of the adhesive strength will be described later.

  In the surface protective film of the present invention, the adhesive strength of the pressure-sensitive adhesive layer to the glass plate is immediately after being attached to the glass plate, after being attached to the glass plate, 50 ° C. × 7 days, 60 ° C. × 90% RH × 7 days later, In any case after 85 ° C. × 7 days, it is preferably 0.5 N / 25 mm or less, more preferably 0.005 N / 25 mm to 0.5 N / 25 mm, and still more preferably 0.005 N / 25 mm to 0.4 N. / 25 mm, particularly preferably 0.005 N / 25 mm to 0.3 N / 25 mm, and most preferably 0.01 N / 25 mm to 0.2 N / 25 mm. When the adhesive strength is within the above range, the surface protective film of the present invention can exhibit more excellent reworkability.

  The surface protective film of the present invention preferably has high transparency. Due to the high transparency of the surface protective film of the present invention, it becomes possible to accurately inspect the surface of the optical member or the electronic member while it is adhered. The surface protective film of the present invention has a haze of preferably 5% or less, more preferably 4% or less, still more preferably 3% or less, particularly preferably 2% or less, and most preferably 1 % Or less.

<B-1. Adhesive layer>
An adhesive layer contains the urethane type adhesive of this invention. The content of the urethane-based pressure-sensitive adhesive of the present invention in the pressure-sensitive adhesive layer is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, and still more preferably 90% to 100%. % By weight, particularly preferably 95% by weight to 100% by weight, and most preferably 98% by weight to 100% by weight. By adjusting the content of the urethane-based pressure-sensitive adhesive of the present invention in the pressure-sensitive adhesive layer within the above range, it is possible to more sufficiently suppress whitening of the adherend and to provide a urethane-based pressure-sensitive adhesive that is superior in reworkability Can do.

  As the thickness of the pressure-sensitive adhesive layer, any appropriate thickness can be adopted depending on the application. The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 100 μm, more preferably 3 μm to 50 μm, and further preferably 5 μm to 30 μm.

  The pressure-sensitive adhesive layer can be produced by any appropriate production method. Examples of such a production method include a method in which a composition that is a material for forming the pressure-sensitive adhesive layer is applied onto the base material layer, and the pressure-sensitive adhesive layer is formed on the base material layer. Examples of such coating methods include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

<B-2. Base material layer>
Any appropriate thickness can be adopted as the thickness of the base material layer depending on the application. The thickness of the base material layer is preferably 5 μm to 300 μm, more preferably 10 μm to 250 μm, still more preferably 15 μm to 200 μm, and particularly preferably 20 μm to 150 μm.

  The base material layer may be a single layer or a laminate of two or more layers. The base material layer may be stretched.

  Any appropriate material can be adopted as the material of the base material layer depending on the application. For example, a plastic, paper, a metal film, a nonwoven fabric, etc. are mentioned. Preferably, it is a plastic. The base material layer may be composed of one kind of material, or may be composed of two or more kinds of materials. For example, you may be comprised from 2 or more types of plastics.

  Examples of the plastic include a polyester resin, a polyamide resin, and a polyolefin resin. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of the polyolefin resin include olefin monomer homopolymers, olefin monomer copolymers, and the like. Specific examples of polyolefin resins include homopolypropylene; block-type, random-type, and graft-type propylene copolymers having an ethylene component as a copolymer component; reactor TPO; low density, high density, linear Low density, ultra-low density, etc. ethylene polymers; ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / acrylic acid And ethylene copolymers such as butyl copolymer, ethylene / methacrylic acid copolymer, and ethylene / methyl methacrylate copolymer.

  The base material layer may contain any appropriate additive as required. Examples of the additive that can be contained in the base material layer include an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a filler, and a pigment. The kind, number, and amount of additives that can be contained in the base material layer can be appropriately set according to the purpose. In particular, when the material of the base material layer is plastic, it is preferable to contain some of the above additives for the purpose of preventing deterioration. From the viewpoint of improving weather resistance and the like, particularly preferred additives include antioxidants, ultraviolet absorbers, light stabilizers, and fillers.

  Any appropriate antioxidant can be adopted as the antioxidant. Examples of such antioxidants include phenol-based antioxidants, phosphorus-based processing heat stabilizers, lactone-based processing heat stabilizers, sulfur-based heat-resistant stabilizers, phenol-phosphorus-based antioxidants, and the like. The content of the antioxidant is preferably 1% by weight or less with respect to the base resin of the base layer (when the base layer is a blend, the blend is the base resin), more preferably It is 0.5 weight% or less, More preferably, it is 0.01 weight%-0.2 weight%.

  Arbitrary appropriate ultraviolet absorbers can be employ | adopted as a ultraviolet absorber. Examples of such UV absorbers include benzotriazole UV absorbers, triazine UV absorbers, and benzophenone UV absorbers. The content ratio of the ultraviolet absorber is preferably 2% by weight or less based on the base resin forming the base layer (when the base layer is a blend, the blend is the base resin), Preferably it is 1 weight% or less, More preferably, it is 0.01 weight%-0.5 weight%.

  Any appropriate light stabilizer can be adopted as the light stabilizer. Examples of such light stabilizers include hindered amine light stabilizers and benzoate light stabilizers. The content ratio of the light stabilizer is preferably 2% by weight or less based on the base resin forming the base layer (when the base layer is a blend, the blend is the base resin). Preferably it is 1 weight% or less, More preferably, it is 0.01 weight%-0.5 weight%.

  Any appropriate filler can be adopted as the filler. Examples of such fillers include inorganic fillers. Specific examples of the inorganic filler include carbon black, titanium oxide, and zinc oxide. The content of the filler is preferably 20% by weight or less with respect to the base resin forming the base layer (when the base layer is a blend, the blend is the base resin), and more preferably Is 10% by weight or less, more preferably 0.01% by weight to 10% by weight.

  Furthermore, as the additive, for the purpose of imparting antistatic properties, inorganic, low molecular weight and high molecular weight antistatic agents such as surfactants, inorganic salts, polyhydric alcohols, metal compounds, carbon and the like are also preferred. In particular, a high molecular weight antistatic agent and carbon are preferable from the viewpoint of contamination and adhesiveness maintenance.

<B-3. Manufacturing method of surface protective film>
The surface protective film of the present invention can be produced by any appropriate method. As such a manufacturing method, for example,
(1) A solution of a pressure-sensitive adhesive layer forming material (for example, a composition containing a polyol (A), a polyfunctional isocyanate compound (B) and a catalyst (C), which is a raw material of the urethane-based pressure-sensitive adhesive of the present invention) A method of applying the hot melt on the base material layer,
(2) A method of transferring the pressure-sensitive adhesive layer applied and formed in the form of a separator onto the base material layer according to that,
(3) A method of forming and applying the forming material of the pressure-sensitive adhesive layer onto the base material layer,
(4) A method of extruding a base material layer and an adhesive layer in two layers or multiple layers,
(5) A method of laminating a pressure-sensitive adhesive layer on a base material layer, or a method of laminating two pressure-sensitive adhesive layers together with a laminate layer,
(6) A method of laminating a pressure-sensitive adhesive layer and a base material layer forming material such as a film or a laminate layer in two or multiple layers,
It can be performed according to any appropriate production method.

≪C. Application >>
The urethane type adhesive of this invention can be used for arbitrary appropriate uses. Preferably, since the urethane-based pressure-sensitive adhesive of the present invention can sufficiently suppress whitening of the adherend and is excellent in reworkability, the surface protective film can be optically used by being used as the pressure-sensitive adhesive layer of the surface protective film. It can use suitably for the surface protection of a member or an electronic member.

  The optical member and the electronic member to which the surface protective film of the present invention is attached can be bonded and peeled many times manually.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. In addition, the test and evaluation method in an Example etc. are as follows. Note that “parts” means “parts by weight” unless otherwise noted, and “%” means “% by weight” unless otherwise noted.

<Measurement of initial adhesive strength to glass plate>
The surface protective film was cut into a width of 25 mm and a length of 150 mm to obtain a sample for evaluation.
Under an atmosphere of temperature 23 ° C. and humidity 50% RH, the pressure-sensitive adhesive layer surface of the sample for evaluation is attached to a glass plate (Matsunami Glass Industry Co., Ltd., trade name: Micro Slide Glass S) by one reciprocating 2.0 kg roller. It was. After curing for 30 minutes in an atmosphere of a temperature of 23 ° C. and a humidity of 50% RH, peeling is performed at a peeling angle of 180 ° and a pulling speed of 300 mm / min using a universal tensile tester (manufactured by Minebea Co., Ltd., product name: TCM-1kNB). The adhesive strength was measured.

<Measurement of adhesive strength after 50 ° C. × 7 days for glass plate>
A sample for evaluation was prepared by the same method as the initial adhesive strength to the glass plate, and the adhesive strength after storage for 7 days at a temperature of 50 ° C. and a humidity of 50% RH was measured by the same method as the initial adhesive strength.

<Measurement of adhesive strength after 60 ° C. × 90% RH × 7 days with respect to glass plate>
A sample for evaluation was prepared in the same manner as the initial adhesive strength to the glass plate, and the adhesive strength after storage for 7 days at a temperature of 60 ° C. and a humidity of 90% RH was measured by the same method as the initial adhesive strength.

<Measurement of Adhesive Force after 85 ° C. × 7 Days for Glass Plate>
A sample for evaluation was prepared by the same method as the initial adhesive strength to the glass plate, and the adhesive strength after storage for 7 days at a temperature of 85 ° C. and a humidity of 50% RH was measured by the same method as the initial adhesive strength.

<Confirmation of bleaching of adherend>
The surface protective film was cut into a width of 25 mm and a length of 150 mm to obtain a sample for evaluation.
Under an atmosphere of temperature 23 ° C. and humidity 50% RH, the pressure-sensitive adhesive layer surface of the sample for evaluation is attached to a glass plate (Matsunami Glass Industry Co., Ltd., trade name: Micro Slide Glass S) by one reciprocating 2.0 kg roller. It was. After curing for 24 hours in an atmosphere of a temperature of 23 ° C. and a humidity of 50% RH, the attached surface protective film is peeled off, and the glass plate on which the surface protective film is attached is visually observed by transmission or reflection in a dark room. The presence or absence of whitening of the surface was confirmed.

[Example 1]
As the polyol (A), Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) which is a polyol having 3 OH groups: 85 parts by weight, Sanniks GP-3000 (Sanyo Chemical Co., Ltd.) which is a polyol having 3 OH groups Sanix GP-1000 (manufactured by Sanyo Chemical Co., Ltd., Mn = 1000): 2 parts by weight using 13 parts by weight and a polyol having 3 OH groups, polyfunctional isocyanate compound (B ) Coronate HX which is a trifunctional alicyclic isocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd., Mn = 504): 18 parts by weight, and as catalyst (C), Nersem ferric iron (iron acetylacetonate, Nippon Chemical Industry Co., Ltd.) (Made by company): 0.04 parts by weight, Irganox 1010 (made by BASF) as an antioxidant: .50 parts by weight of ethyl acetate as a diluting solvent: by blending 210 parts by weight, and stirred with a disper, to obtain a urethane-based pressure-sensitive adhesive composition. The obtained urethane pressure-sensitive adhesive composition was applied to a base material “Lumirror S10” (thickness 38 μm, manufactured by Toray Industries, Inc.) made of a polyester resin so that the thickness after drying with a fountain roll was 12 μm, and the drying temperature was 130 ° C. It was cured and dried under the condition of a drying time of 2 minutes. Thus, the adhesive layer which consists of urethane type adhesives (1) on a base material was produced.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.
Next, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (1).
The evaluation results are shown in Table 1.

[Example 2]
As a component of the urethane-based pressure-sensitive adhesive composition, fatty acid ester (isopropyl palmitate, manufactured by Kao Corporation, trade name: Exepearl IPP, Mn = 299): Except for adding 30 parts by weight, the same as in Example 1, A pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (2) was produced on the substrate.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.
Next, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (2).
The evaluation results are shown in Table 1.

Example 3
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): A pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (3) was produced on the substrate except that 0.005 part by weight was used.
The molar ratio of (Sn catalyst / Fe catalyst) in the catalyst (C) was 0.06.
Next, the surface of the pressure-sensitive adhesive layer was pasted with the silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (3).
The evaluation results are shown in Table 1.

Example 4
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): A pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (4) was produced on the substrate except that 0.005 part by weight was used.
The molar ratio of (Sn catalyst / Fe catalyst) in the catalyst (C) was 0.06.
Next, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (4).
The evaluation results are shown in Table 1.

Example 5
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): A pressure-sensitive adhesive layer made of a urethane pressure-sensitive adhesive (5) was produced on the base material except that 0.01 part by weight was used.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.12.
Next, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (5).
The evaluation results are shown in Table 2.

Example 6
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): A pressure-sensitive adhesive layer made of a urethane pressure-sensitive adhesive (6) was produced on the base material except that 0.01 part by weight was used.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.12.
Next, the surface of the pressure-sensitive adhesive layer was pasted with the silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (6).
The evaluation results are shown in Table 2.

Example 7
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): A pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (7) was produced on the substrate except that 0.02 part by weight was used.
The molar ratio of (Sn catalyst / Fe catalyst) in the catalyst (C) was 0.24.
Next, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (7).
The evaluation results are shown in Table 2.

Example 8
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): A pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (8) was produced on the substrate except that 0.02 part by weight was used.
The molar ratio of (Sn catalyst / Fe catalyst) in the catalyst (C) was 0.24.
Next, the surface of the pressure-sensitive adhesive layer was pasted with the silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (8).
The evaluation results are shown in Table 2.

[Comparative Example 1]
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): Except for using 0.04 parts by weight, the same procedure as in Example 1 was performed to prepare a pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (C1) on the substrate.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.47.
Next, the surface of the pressure-sensitive adhesive layer was pasted with the silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (C1).
The evaluation results are shown in Table 3.

[Comparative Example 2]
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): A pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (C2) was produced on the substrate except that 0.04 part by weight was used.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.47.
Subsequently, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (C2).
The evaluation results are shown in Table 3.

[Comparative Example 3]
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): Except for using 0.08 parts by weight, the same procedure as in Example 1 was performed to prepare a pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (C3) on the substrate.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.95.
Next, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (C3).
The evaluation results are shown in Table 3.

[Comparative Example 4]
As a component of the urethane-based pressure-sensitive adhesive composition, as a catalyst (C), nasem ferric iron (iron acetylacetonate, manufactured by Nippon Kagaku Sangyo Co., Ltd.): 0.04 parts by weight and an equalizer OL-1 (dioctyltin dilaurate type) Catalyst, manufactured by Tokyo Fine Chemical Co., Ltd.): Except for using 0.08 parts by weight, the same procedure as in Example 2 was performed to prepare a pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (C4) on the substrate.
The molar ratio of (Sn-based catalyst / Fe-based catalyst) in the catalyst (C) was 0.95.
Next, the surface of the pressure-sensitive adhesive layer was pasted with a silicone-treated surface of a base material made of a polyester resin having a thickness of 25 μm and subjected to silicone treatment on one surface to obtain a surface protective film (C4).
The evaluation results are shown in Table 3.

Example 9
The surface protective film (1) obtained in Example 1 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 10
The surface protective film (2) obtained in Example 2 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 11
The surface protective film (3) obtained in Example 3 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 12
The surface protective film (4) obtained in Example 4 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 13
The surface protective film (5) obtained in Example 5 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 14
The surface protective film (6) obtained in Example 6 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 15
The surface protective film (7) obtained in Example 7 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 16
The surface protective film (8) obtained in Example 8 was attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name “TEG1465DUHC”) which is an optical member, and the optical member to which the surface protective film was attached was attached. Obtained.

Example 17
The surface protective film (1) obtained in Example 1 was attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film was attached. An electronic member was obtained.

Example 18
The surface protective film (2) obtained in Example 2 is attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film is attached. An electronic member was obtained.

Example 19
The surface protective film (3) obtained in Example 3 was attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film was attached. An electronic member was obtained.

Example 20
The surface protective film (4) obtained in Example 4 was attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film was attached. An electronic member was obtained.

Example 21
The surface protective film (5) obtained in Example 5 was attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film was attached. An electronic member was obtained.

[Example 22]
The surface protective film (6) obtained in Example 6 was attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film was attached. An electronic member was obtained.

Example 23
The surface protective film (7) obtained in Example 7 was attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film was attached. An electronic member was obtained.

Example 24
The surface protective film (8) obtained in Example 8 was attached to a conductive film (Nitto Denko Corporation, trade name “Electrista V270L-TFMP”) which is an electronic member, and the surface protective film was attached. An electronic member was obtained.

  By using the urethane-based pressure-sensitive adhesive of the present invention as, for example, a pressure-sensitive adhesive layer of a surface protective film, the surface protective film can be suitably used for surface protection of optical members and electronic members.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Adhesive layer 10 Surface protection film

Claims (9)

A urethane-based adhesive containing a polyurethane-based resin,
The polyurethane resin is a polyurethane resin obtained by curing a composition containing a polyol (A), a polyfunctional isocyanate compound (B) and a catalyst (C),
The catalyst (C) is a catalyst system satisfying (Sn-based catalyst / Fe-based catalyst) ≦ 0.3 by molar ratio.
Urethane adhesive.   The urethane-based pressure-sensitive adhesive according to claim 1, wherein the content ratio of the catalyst (C) to the polyol (A) is 0.0005 wt% to 0.5 wt%.   The urethane-based pressure-sensitive adhesive according to claim 1 or 2, wherein the polyol (A) is two or more kinds of polyols.   The urethane-based pressure-sensitive adhesive according to any one of claims 1 to 3, wherein the polyol (A) is a polyol having a number average molecular weight Mn of 400 to 20000.   The urethane-based pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the polyol (A) is a polyether polyol.   The urethane-based pressure-sensitive adhesive according to any one of claims 1 to 5, wherein a content ratio of the polyfunctional isocyanate compound (B) to the polyol (A) is 5% by weight to 60% by weight. Having a base material layer and an adhesive layer,
The pressure-sensitive adhesive layer contains the urethane-based pressure-sensitive adhesive according to any one of claims 1 to 6.
Surface protective film.   An optical member to which the surface protective film according to claim 7 is attached. An electronic member to which the surface protective film according to claim 7 is attached.

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