KR20150039714A - Adhesive - Google Patents

Abstract

The present invention provides a pressure-sensitive adhesive comprising a polyurethane resin excellent in initial reworkability when bonded to an adherend and having excellent adhesion reliability over time. Also provided is a pressure-sensitive adhesive sheet or a surface protective film having a pressure-sensitive adhesive layer containing such a pressure-sensitive adhesive. In addition, an optical member or an electronic member to which such a pressure-sensitive adhesive sheet or a surface protective film is adhered is provided. When the initial adhesive force immediately after bonding to an acrylic plate is A and the adhesive force after adhesion at 70 DEG C x 1 day is B, the initial adhesive force A Is from 0.001 N / 20 mm to 2.0 N / 20 mm, and the adhesive force B after 70 ° C × 1 day is 2.0 times or more of the initial adhesive force A.

Description

Adhesive {ADHESIVE}

The present invention relates to a pressure-sensitive adhesive. The pressure-sensitive adhesive of the present invention has excellent initial reworkability when bonded to an adherend, and is excellent in adhesion reliability after a lapse of time. The present invention also relates to an adhesive sheet having a pressure-sensitive adhesive layer containing such a pressure-sensitive adhesive on at least one side of a base layer. The present invention also relates to a surface protective film having a pressure-sensitive adhesive layer containing such a pressure-sensitive adhesive on one surface of a base layer. The pressure-sensitive adhesive sheet of the present invention is preferably used, for example, for the purpose of adhesively fixing various members such as optical members and electronic members. The surface protective film of the present invention is suitably used, for example, for the purpose of protecting the surface by bonding to the surface of an optical member or an electronic member, for example.

Optical members and electronic members such as LCDs, organic ELs, touch panels using them, lens parts of cameras, electronic devices, etc., are generally arranged on the exposed surface side in order to prevent surface scratches during processing, assembly, The surface protective film is bonded. Such a surface protective film is peeled off from the optical member or the electron member at the time when the need for surface protection is eliminated.

When the surface protective film is adhered manually by hand, bubbles may be mixed in between the adherend and the surface protective film. Therefore, several techniques for improving the wettability of the surface protective film so as not to incorporate bubbles at the time of bonding have been reported. For example, a surface protective film using a silicone resin having a high wetting speed as a pressure-sensitive adhesive layer is known. However, when a silicone resin is used for the pressure-sensitive adhesive layer, the pressure-sensitive adhesive component tends to contaminate the adherend and is used as a surface protective film for protecting the surface of a member requiring particularly low contamination such as optical members and electronic members .

BACKGROUND ART [0002] As a surface protective film having little contamination derived from a pressure-sensitive adhesive component, a surface protective film using an acrylic resin as a pressure-sensitive adhesive layer is known. However, since the surface protective film using an acrylic resin as a pressure sensitive adhesive layer is poor in wettability, when a surface protective film is adhered by hand, air bubbles may be mixed between the adherend and the surface protective film. Further, when an acrylic resin is used for the pressure-sensitive adhesive layer, there is a problem that the pressure-sensitive adhesive residue tends to be generated at the time of peeling, and is used as a surface protective film for protecting the surface of a member, There is a problem.

A surface protective film using a polyurethane resin as a pressure-sensitive adhesive layer has recently been reported as a surface protective film capable of achieving excellent wettability, low staining property and reduction in pressure-sensitive adhesive residue (see, for example, Patent Document 1).

Here, depending on the application, when the surface protective film is manually bonded to an adherend, excellent wettability as well as excellent initial reworkability are required. The surface protective film adhered to the adherend may need to be peeled immediately after bonding in order to correct the positional deviation and the like. In this case, the surface protective film can be lightly peeled without being deformed, It is required to be able to re-adhere to it. In addition, in applications where re-peeling is not frequently performed after re-bonding as described above, excellent adhesion reliability is required after a lapse of time in order to avoid troubles that are easily peeled off.

As described above, there is a demand for a pressure-sensitive adhesive comprising a polyurethane resin which is excellent in initial reworkability when bonded to an adherend, and has excellent adhesion reliability over time. The adhesive sheet using such a pressure-sensitive adhesive can be provided, for example, for the purpose of adhering and fixing various members such as optical members and electronic members. Further, if a surface protective film using such a pressure-sensitive adhesive can be provided, it is effective, for example, for the purpose of protecting the surface by bonding to the surface of an optical member or an electronic member.

Japanese Patent Application Laid-Open No. 2006-182795

An object of the present invention is to provide a pressure-sensitive adhesive comprising a polyurethane resin excellent in initial reworkability when bonded to an adherend and having excellent adhesion reliability over time. Another object of the present invention is to provide a pressure-sensitive adhesive sheet or a surface protective film having a pressure-sensitive adhesive layer containing such a pressure-sensitive adhesive. Another object of the present invention is to provide an optical member or an electronic member to which such a pressure-sensitive adhesive sheet or a surface protective film is adhered.

In the pressure-sensitive adhesive of the present invention,

A pressure-sensitive adhesive comprising a polyurethane resin,

Assuming that the initial adhesive force immediately after bonding to the acrylic plate is A and the adhesive force after bonding at 70 DEG C x 1 day is B,

The initial adhesive force A is 0.001 N / 20 mm to 2.0 N / 20 mm,

The adhesive strength B after 70 ° C × 1 day is 2.0 times or more of the initial adhesion strength A.

In a preferred embodiment, the polyurethane resin is a polyurethane resin obtained by curing a composition containing a polyol (A) having two or more OH groups and a polyfunctional isocyanate compound (B).

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

In a preferred embodiment, at least one of the two or more polyols is a polyol having two OH groups, and at least one of them is a polyol having three or more OH groups.

In a preferred embodiment, the polyol having two OH groups has a number average molecular weight Mn of 6,000 or more, and the number average molecular weight Mn of the polyol having three or more OH groups is 2,000 or more.

In a preferred embodiment, the number average molecular weight Mn of the polyol having two OH groups is less than 6,000, the number average molecular weight Mn of the polyol having three or more OH groups is less than 2000, and the polyol (A) The equivalent ratio of the NCO group and the OH group in the isocyanate compound (B) is less than 1.3 as the NCO group / OH group.

In a preferred embodiment, the polyol (A) contains at least 50% by weight of a polyol having two OH groups.

In a preferred embodiment, the amount of the catalyst (C) used for obtaining the polyurethane resin by curing is 0.01 part by weight or more based on 100 parts by weight of the polyol (A).

The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive of the present invention on at least one side of the base layer.

The optical member of the present invention is obtained by adhering the adhesive sheet of the present invention.

The electronic member of the present invention is one to which the adhesive sheet of the present invention is adhered.

The surface protective film of the present invention has a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive of the present invention on one side of the base layer.

In a preferred embodiment, the surface protective film of the present invention is used for surface protection of optical members or electronic members.

The optical member of the present invention is one to which the surface protective film of the present invention is adhered.

The electronic member of the present invention is one to which the surface protective film of the present invention is adhered.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a pressure-sensitive adhesive comprising a polyurethane resin excellent in initial reworkability when bonded to an adherend and having excellent adhesion reliability over time. It is also possible to provide a pressure-sensitive adhesive sheet or a surface protective film having a pressure-sensitive adhesive layer containing such a pressure-sensitive adhesive. Further, an optical member or an electronic member to which such a pressure-sensitive adhesive sheet or a surface protective film is adhered can be provided.

1 is a schematic sectional view of a surface protective film according to a preferred embodiment of the present invention.

"A. adhesive"

The pressure-sensitive adhesive of the present invention contains a polyurethane resin as a main component. The content of the polyurethane resin in the pressure-sensitive adhesive of the present invention is preferably 90 wt% to 100 wt%, more preferably 95 wt% to 100 wt%, and further preferably 98 wt% to 100 wt% . The pressure-sensitive adhesive may be of only one type, or may be two or more types.

The initial adhesive force A of the pressure-sensitive adhesive of the present invention is 0.001 N / 20 mm to 2.0 N / 20 mm, preferably 0.005 N / 20 mm to 1.8 N / 20 mm, more preferably 0.01 N / 20 mm to 1.5 N / 20 mm, particularly preferably 0.1 N / 20 mm to 1.3 N / 20 mm, and most preferably 0.15 N / N / 20 mm. Since the initial adhesive force A is in the above range, the pressure-sensitive adhesive of the present invention is excellent in initial reworkability when adhered to an adherend. The measurement of the initial adhesive force A will be described later.

The pressure-sensitive adhesive of the present invention has an adhesive force B at 70 ° C x 1 day, preferably 0.1 N / 20 mm or more, more preferably 0.5 N / 20 mm or more, more preferably 1.0 N / 20 mm or more, particularly preferably 1.5 N / 20 mm or more. The upper limit value of the adhesive force B after 70 ° C × 1 day is preferably 10 N / 20 mm or less. Since the adhesive strength B after 70 ° C × 1 day is within the above range, the pressure-sensitive adhesive of the present invention is excellent in adhesion reliability over time after being adhered to an adherend. The measurement of the adhesive force B after 70 占 폚 for 1 day will be described later.

In the pressure-sensitive adhesive of the present invention, the adhesive strength B after 70 ° C × 1 day is 2.0 times or more, preferably 3.0 times or more, more preferably 4.0 times or more, particularly preferably 5.0 times or more , And most preferably 10 times or more. The upper limit of the magnification with respect to the initial adhesion force A of the adhesive force B after 70 ° C × 1 day is preferably 100 times or less. Since the magnification of the adhesive force B after 70 ° C × 1 day with respect to the initial adhesive force A is within the above range, the pressure-sensitive adhesive of the present invention is excellent in adhesion reliability after the passage of time when adhered to an adherend. The measurement of the adhesive force B after 70 占 폚 for 1 day will be described later.

The polyurethane resin is preferably obtained by curing a composition containing a polyol (A) having at least two OH groups and a polyfunctional isocyanate compound (B). By employing such a polyurethane resin, the pressure-sensitive adhesive of the present invention has excellent initial reworkability when bonded to an adherend, and is excellent in adhesion reliability after a lapse of time. Further, by employing such a polyurethane resin, the pressure-sensitive adhesive of the present invention can achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue.

The polyol (A) may be of only one kind or two or more kinds. Preferably, the polyol (A) is at least two kinds of polyols. Since the polyol (A) is at least two kinds of polyols, the pressure-sensitive adhesive of the present invention has excellent initial reworkability when bonded to an adherend, and is excellent in adhesion reliability after a lapse of time. Further, since the polyol (A) is at least two kinds of polyols, the pressure-sensitive adhesive of the present invention can both achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue.

The polyol (A) is preferably at least two kinds of polyols. In this case, at least one kind of the polyol is preferably a polyol having two OH groups, and at least one kind thereof is a polyol having three or more OH groups Lt; / RTI > By employing such a polyol (A), the pressure-sensitive adhesive of the present invention has excellent initial reworkability when bonded to an adherend, and is excellent in adhesion reliability after a lapse of time. Further, by employing such a polyol (A), the pressure-sensitive adhesive of the present invention can achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue.

The number average molecular weight Mn of the polyol having two OH groups contained in the polyol (A) is preferably 6,000 or more, more preferably 7,000 or more, still more preferably 8,000 or more, 9000 or more. The upper limit value of the number average molecular weight Mn is preferably 20,000 or less. By adjusting the number average molecular weight Mn of the polyol having two OH groups contained in the polyol (A) within the above-mentioned range, the pressure-sensitive adhesive of the present invention has an excellent early riser property when adhered to an adherend, Excellent adhesion reliability. Further, by adjusting the number average molecular weight Mn of the polyol having two OH groups contained in the polyol (A) to fall within the above range, the pressure-sensitive adhesive of the present invention can achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue.

The number average molecular weight Mn of the polyol having three or more OH groups contained in the polyol (A) is preferably 2000 or more, more preferably 2,500 or more, still more preferably 3,000 or more, Is more than 3500. The upper limit value of the number average molecular weight Mn is preferably 20,000 or less. By adjusting the number average molecular weight Mn of the polyol having three or more OH groups contained in the polyol (A) to fall within the above range, the pressure-sensitive adhesive of the present invention exhibits excellent early riser properties when adhered to an adherend, Adhesion reliability is excellent. Further, by adjusting the number average molecular weight Mn of the polyol having three or more OH groups contained in the polyol (A) to fall within the above range, the pressure-sensitive adhesive of the present invention can achieve both excellent wettability, low staining property and reduced pressure-sensitive adhesive residue.

The polyol (A) preferably contains 50% by weight or more, more preferably 55% by weight or more, still more preferably 60% by weight or more, and still more preferably 62% by weight or more of a polyol having two OH groups By weight or more, particularly preferably 65% by weight or more, and most preferably 67% by weight or more. By employing such a polyol (A), the pressure-sensitive adhesive of the present invention has excellent initial reworkability when bonded to an adherend, and is excellent in adhesion reliability after a lapse of time. Further, by employing such a polyol (A), the pressure-sensitive adhesive of the present invention can achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue.

Examples of the polyol (A) include a polyester polyol, a polyether polyol, a polycaprolactone polyol, a polycarbonate polyol, and a castor oil-based polyol.

The polyester polyol can be obtained, for example, by an esterification reaction of 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, 1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, -Methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polypropylene glycol and the like.

Examples of the acid component include organic acids such as succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, 4-cyclohexane dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalene dicarboxylic acid, 4-cyclohexane dicarboxylic acid, 4'-biphenyldicarboxylic acid, and their acid anhydrides.

Examples of the polyether polyol include water, low molecular polyols (propylene glycol, ethylene glycol, glycerin, trimethylol propane, pentaerythritol, etc.), bisphenols (such as bisphenol A), dihydroxybenzenes , Hydroquinone and the like) as an initiator and addition polymerization of an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide and the like. Specific examples thereof include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Examples of the polycaprolactone polyol include caprolactone polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as? -Caprolactone and? -Valerolactone.

The polycarbonate polyol includes, for example, polycarbonate polyol obtained by polycondensation reaction of the polyol component and phosgene; The above-mentioned polyol component is mixed with the carbonic acid di (methane) carbonate such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, Polycarbonate polyols obtained by ester exchange condensation of esters; A copolymerized polycarbonate polyol obtained by using two or more of the above polyol components in combination; A polycarbonate polyol obtained by esterifying the above various polycarbonate polyols and a carboxyl group-containing compound; A polycarbonate polyol obtained by etherifying the various polycarbonate polyols and a hydroxyl group-containing compound; A polycarbonate polyol obtained by transesterifying various polycarbonate polyols and an ester compound; A polycarbonate polyol obtained by transesterifying the various polycarbonate polyols and a hydroxyl group-containing compound; A polyester polycarbonate polyol obtained by polycondensation reaction of the various polycarbonate polyols and a dicarboxylic acid compound; A copolymerized polyether polycarbonate polyol obtained by copolymerizing the various polycarbonate polyols and an alkylene oxide; And the like.

Examples of the castor oil-based polyol include a castor oil-based polyol obtained by reacting a castor oil fatty acid with the polyol component. Specifically, there may be mentioned, for example, castor oil-based polyols obtained by reacting castor oil fatty acid with polypropylene glycol.

The polyfunctional isocyanate compound (B) may be one kind or two or more kinds.

As the polyfunctional isocyanate compound (B), any suitable polyfunctional isocyanate compound which can be used for the urethanization reaction can be employed. Examples of the polyfunctional isocyanate compound (B) include a polyfunctional aliphatic isocyanate compound, a polyfunctional alicyclic isocyanate, and a polyfunctional aromatic isocyanate compound.

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

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

Examples of the polyfunctional aromatic diisocyanate compound include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, '-Diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylylenedi Isocyanate and the like.

Examples of the polyfunctional isocyanate compound (B) include trimethylolpropane adducts of various polyfunctional isocyanate compounds as described above, burettes obtained by reacting with water, and trimesters having isocyanurate rings. They may also be used in combination.

The polyfunctional isocyanate compound (B) is preferably a polyfunctional aromatic diisocyanate compound. By employing a multifunctional aromatic diisocyanate compound as the polyfunctional isocyanate compound (B), whitening of the resulting pressure-sensitive adhesive can be suppressed and high transparency can be imparted. When the pressure-sensitive adhesive of the present invention can be imparted with high transparency, the transparency of the surface protective film of the present invention having the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive of the present invention can be enhanced. It is possible to perform the inspection or the like accurately in a state of being adhered to the substrate.

The polyurethane resin is preferably obtained by curing a composition containing the polyol (A) and the polyfunctional isocyanate compound (B). Such a composition may contain any other appropriate components other than the polyol (A) and the polyfunctional isocyanate compound (B) within a range that does not impair the effect of the present invention. Examples of such other components include a catalyst, a resin component other than a polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a foaming agent, a softener, a plasticizer, an antioxidant, a conductive agent, Antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents and the like.

The weight ratio of the polyol (A) to the polyfunctional isocyanate compound (B) is preferably 30 parts by weight or less, more preferably 28 parts by weight or less, and still more preferably 30 parts by weight or less, per 100 parts by weight of the polyol (A) More preferably 25 parts by weight or less, particularly preferably 23 parts by weight or less. The lower limit of the weight ratio of the polyfunctional isocyanate compound (B) to the polyol (A) is preferably 5 parts by weight or more based on 100 parts by weight of the polyol (A). By adjusting the weight ratio of the polyol (A) to the polyfunctional isocyanate compound (B) within the above-mentioned range, the pressure-sensitive adhesive of the present invention has excellent initial reworkability when bonded to an adherend and has excellent adhesion reliability over time . Further, by adjusting the weight ratio of the polyol (A) to the polyfunctional isocyanate compound (B) within the above range, the pressure-sensitive adhesive of the present invention can achieve excellent wettability, low staining property and reduced pressure-sensitive adhesive residue.

The equivalent ratio of the NCO group and the OH group in the polyol (A) and the polyfunctional isocyanate compound (B) is preferably from 0.1 to 5.0, more preferably from 0.2 to 4.0, Is 0.3 to 3.0. By adjusting the equivalent ratio of the NCO group / OH group within the above range, the pressure-sensitive adhesive of the present invention is excellent in initial reworkability when bonded to an adherend, and is excellent in adhesion reliability over time. Further, by adjusting the equivalent ratio of the NCO group / OH group within the above range, the pressure-sensitive adhesive of the present invention can achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue. When a polyol having two OH groups having a number average molecular weight Mn of less than 6000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2000 are used in combination as the polyol (A), the equivalent ratio of the NCO group and the OH group is The NCO group / OH group is preferably less than 1.3, more preferably from 0.1 to 1.2, still more preferably from 0.1 to 1.1, and particularly preferably from 0.1 to 1.0. When the polyol having two OH groups having a number average molecular weight Mn of less than 6000 and the polyol having three or more OH groups having a number average molecular weight Mn of less than 2000 are used as the polyol (A), the equivalent ratio of the NCO group / , The pressure-sensitive adhesive of the present invention is excellent in initial reworkability when bonded to an adherend, and is excellent in adhesion reliability after a lapse of time. When a polyol having two OH groups having a number average molecular weight Mn of less than 6000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2000 are used in combination as the polyol (A), the equivalent ratio of NCO group / OH group Is adjusted within the above-mentioned range, the pressure-sensitive adhesive of the present invention can achieve both excellent wettability, low staining property, and pressure-sensitive adhesive residue reduction.

As a method of curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B) to obtain a polyurethane-based resin, a method of reacting with a polyurethane resin such as a urethane-forming reaction method using bulk polymerization, Any suitable method in the range may be employed.

In order to cure the composition containing the polyol (A) and the polyfunctional isocyanate compound (B), the catalyst (C) is preferably used. Examples of the catalyst (C) include organic metal compounds, tertiary amine compounds and the like.

Examples of the organometallic compounds include iron compounds, tin compounds, titanium compounds, zirconium compounds, lead compounds, cobalt compounds, zinc compounds and the like. Of these, iron-based compounds are preferred because of their high reactivity.

Examples of the iron-based compound include iron acetylacetonate and 2-ethylhexanoate.

The tin compound includes, for example, dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin diacetate, Tributyltin acetate, tributyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, tributyltin trichloroacetate, 2-ethylhexanoate tin and the like.

Examples of the titanium-based compound include dibutyltitanium dichloride, tetrabutyl titanate, butoxy titanium trichloride and the like.

Examples of the zirconium-based compound include zirconium naphthenate, zirconium acetylacetonate, and the like.

Examples of lead-based compounds include lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, and the like.

Examples of the cobalt-based compound include cobalt 2-ethylhexanoate and cobalt benzoate.

Examples of zinc-based compounds include zinc naphthenate and zinc 2-ethylhexanoate.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo- (5,4,0) -undecene-7, and the like.

The catalyst (C) may be one kind or two or more kinds. The amount of the catalyst (C) to be used is preferably 0.01 parts by weight or more, more preferably 0.08 parts by weight or more, still more preferably 0.1 parts by weight or more, and particularly preferably 0.15 parts by weight or less per 100 parts by weight of the polyol (A) Parts by weight or more. The upper limit value of the amount of the catalyst (C) to be used is preferably 5 parts by weight or less. By adjusting the amount of the catalyst (C) to fall within the above range, the pressure-sensitive adhesive of the present invention is excellent in initial reworkability when bonded to an adherend, and has excellent adhesion reliability after a lapse of time. Further, by adjusting the amount of the catalyst (C) within the above-mentioned range, the pressure-sensitive adhesive of the present invention can both achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue. When a polyol having two OH groups having a number average molecular weight Mn of less than 6000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2000 are used in combination as the polyol (A), the amount of the catalyst (C) Is adjusted within the above range, the pressure-sensitive adhesive of the present invention exhibits excellent initial reworkability when bonded to an adherend, and is excellent in adhesion reliability after a lapse of time. When a polyol having two OH groups having a number average molecular weight Mn of less than 6000 and a polyol having three or more OH groups having a number average molecular weight Mn of less than 2000 are used in combination as the polyol (A), the amount of the catalyst (C) Is adjusted to fall within the above range, the pressure-sensitive adhesive of the present invention can achieve excellent wettability, low staining property, and reduced pressure-sensitive adhesive residue.

The pressure-sensitive adhesive of the present invention may contain, in addition to the polyurethane resin as described above, any other suitable components as long as the effect of the present invention is not impaired. Examples of such other components include a resin component other than the polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a foil, a softener, a plasticizer, an antioxidant, a conductive agent, A light stabilizer, a surface lubricant, a leveling agent, a corrosion inhibitor, a heat stabilizer, a polymerization inhibitor, a lubricant, and a solvent.

The pressure-sensitive adhesive layer containing the pressure-sensitive adhesive of the present invention can be formed by any suitable method. Such a pressure-sensitive adhesive layer can be obtained by applying a pressure-sensitive adhesive material on an arbitrary suitable support to form a pressure-sensitive adhesive. In this case, the member to be the base layer of the surface protective film may be used as a support, and the pressure sensitive adhesive formed on any other suitable support may be finally transferred onto a member to be a base layer of the surface protective film, .

Examples of the method of applying the pressure-sensitive adhesive material include roll coating, gravure coating, reverse coating, roll brush, spray coating, air knife coating, extrusion coating by a die coater and the like.

"B. Adhesive sheet and surface protective film "

The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive of the present invention on at least one side of the base layer. The surface protective film of the present invention has a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive of the present invention on one side of the base layer. The pressure-sensitive adhesive sheet of the present invention is preferably used, for example, for the purpose of adhesively fixing various members such as optical members and electronic members. The surface protective film of the present invention is suitably used, for example, for the purpose of protecting the surface by bonding to the surface of an optical member or an electronic member, for example.

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

1 is a schematic sectional view of a pressure-sensitive adhesive sheet or a surface protective film according to a preferred embodiment of the present invention. The adhesive sheet or the surface protection film (10) comprises a base layer (1) and a pressure-sensitive adhesive layer (2). The pressure-sensitive adhesive sheet or surface protective film of the present invention may further comprise any other suitable layer (not shown) if necessary.

The pressure-sensitive adhesive sheet of the present invention may have a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive of the present invention on both sides of the base layer. That is, in FIG. 1, the pressure-sensitive adhesive layer may be further provided on the opposite side of the pressure-sensitive adhesive layer 2 of the base layer 1.

When there is a surface of the substrate layer 1 on which the pressure-sensitive adhesive layer 2 is not laid, for the purpose of forming a roll easily rewound, etc., for example, a fatty acid amide, polyethylene Imine, long-chain alkyl-based additive or the like may be added to perform the release treatment, or a coating layer containing any appropriate releasing agent such as a silicone type, a long chain alkyl type or a fluorine type may be formed.

The pressure-sensitive adhesive sheet and the surface protective film of the present invention may be bonded to a release liner having releasability.

The thickness of the pressure-sensitive adhesive sheet and the surface protective film of the present invention can be set to any suitable thickness depending on the application. From the viewpoint of fully manifesting the effect of the present invention, it is preferably from 10 탆 to 300 탆, more preferably from 15 탆 to 250 탆, still more preferably from 20 탆 to 200 탆, particularly preferably from 25 탆 To 150 mu m.

The pressure-sensitive adhesive sheet and the surface protective film of the present invention preferably have high transparency. The high transparency of the pressure-sensitive adhesive sheet and the surface protective film of the present invention makes it possible to conduct an inspection or the like accurately in a state of being adhered to the surface of an optical member or an electronic member. The pressure-sensitive adhesive sheet and surface protective film of the present invention preferably have a haze of 5% or less, more preferably 4% or less, still more preferably 3% or less, particularly preferably 2% or less, Is less than 1%.

As the thickness of the base layer, any appropriate thickness may be adopted depending on the application. The thickness of the base layer is preferably 5 to 300 탆, more preferably 10 to 250 탆, still more preferably 15 to 200 탆, and particularly preferably 20 to 150 탆.

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

As the material of the base layer, any suitable material may be employed depending on the application. For example, plastic, paper, metal film, non-woven fabric, and the like. It is preferably a plastic. The base layer may be composed of one kind of material or may be composed of two or more kinds of materials. For example, two or more kinds of plastics.

Examples of the plastic include a polyester-based resin, a polyamide-based resin, and a polyolefin-based resin. Examples of the polyester-based resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of the polyolefin-based resin include a homopolymer of an olefin monomer, a copolymer of an olefin monomer, and the like. Specific examples of the polyolefin-based resin include homopolypropylene; Propylene-based copolymers such as a block system, a random system and a graft system having an ethylene component as a copolymerization component; Reactor TPO; Ethylene polymers such as low density, high density, linear low density and ultra low density; Ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / methyl acrylate copolymer, ethylene · ethyl acrylate copolymer, ethylene · butyl acrylate copolymer, ethylene · methacrylic acid copolymer, ethylene · methyl methacrylate copolymer And the like; And the like.

The base layer may contain any suitable additives as required. Examples of additives that can be contained in the base layer include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, pigments and the like. The kind, quantity, and amount of the additive that may be contained in the base layer may be appropriately set according to the purpose. Particularly, in the case where the material of the substrate layer is plastic, it is preferable to contain some of the additives in order to prevent deterioration or the like. From the viewpoint of improving weatherability and the like, additives such as an antioxidant, an ultraviolet absorber, a light stabilizer and a filler are particularly preferable.

As the antioxidant, any suitable antioxidant may be employed. Examples of such antioxidants include phenol-based antioxidants, phosphorus-based heat stabilizers, lactone-based heat stabilizers, sulfur-based heat stabilizers, and phenol-phosphorus antioxidants. The content of the antioxidant is preferably 1 part by weight or less, more preferably 0.5 part by weight or less based on 100 parts by weight of the base resin of the base layer (when the base layer is a blend, the amount of the blend is base resin) , And more preferably 0.01 part by weight to 0.2 part by weight.

Any suitable ultraviolet absorber may be employed as the ultraviolet absorber. Examples of such ultraviolet absorbers include benzotriazole ultraviolet absorbers, triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and the like. The content of the ultraviolet absorber is preferably 2 parts by weight or less, more preferably 1 part by weight or less, more preferably 1 part by weight or less, based on 100 parts by weight of the base resin forming the base layer (when the base layer is a blend, By weight and more preferably 0.01 part by weight to 0.5 part by weight.

As the light stabilizer, any suitable light stabilizer may be employed. Examples of such light stabilizers include hindered amine light stabilizers, benzoate light stabilizers, and the like. The content of the light stabilizer is preferably 2 parts by weight or less, more preferably 1 part by weight or less, and still more preferably 1 part by weight or less, based on 100 parts by weight of the base resin forming the base layer (when the base layer is a blend, By weight and more preferably 0.01 part by weight to 0.5 part by weight.

Any suitable filler may be employed as the filler. Examples of such a filler include an inorganic filler and the like. Specific examples of the inorganic filler include carbon black, titanium oxide, zinc oxide and the like. The content of the filler is preferably 20 parts by weight or less, more preferably 10 parts by weight or less based on 100 parts by weight of the base resin forming the base layer (when the base layer is a blend, the blend is base resin) More preferably 0.01 part by weight to 10 parts by weight.

As the additive, inorganic, low molecular weight and high molecular weight antistatic agents such as surfactants, inorganic salts, polyhydric alcohols, metal compounds and carbon are preferably used for the purpose of imparting antistatic properties. Particularly, from the viewpoints of keeping contamination and tackiness, high molecular weight antistatic agents and carbon are preferable.

The pressure-sensitive adhesive sheet and surface protective film of the present invention can be used in any suitable application. The pressure-sensitive adhesive sheet of the present invention is preferably used, for example, for the purpose of adhesively fixing various members such as optical members and electronic members. The surface protective film of the present invention is suitably used, for example, for the purpose of protecting the surface by bonding to the surface of an optical member or an electronic member, for example.

The optical member to which the pressure-sensitive adhesive sheet of the present invention is adhered can be bonded and peeled by hand several times.

The electronic member to which the adhesive sheet of the present invention is adhered can be bonded and peeled by hand several times.

The optical member to which the surface protective film of the present invention is adhered can be bonded and peeled by hand several times.

The electronic member to which the surface protective film of the present invention is adhered can be bonded and peeled by hand several times.

The pressure-sensitive adhesive sheet and the surface protecting film of the present invention can be produced by any suitable method. Such manufacturing methods include, for example,

(1) a method of applying a solution or thermal melt of a material for forming a pressure-sensitive adhesive layer (for example, a composition containing a polyurethane resin)

(2) a method of adhering (transferring) the pressure-sensitive adhesive layer coated and formed in the form of a separator on the base layer,

(3) a method of extruding and forming a pressure-sensitive adhesive layer forming material on a base layer,

(4) a method of extruding the base layer and the pressure-sensitive adhesive layer into two layers or multiple layers,

(5) a method in which the pressure-sensitive adhesive layer is laminated on the base layer or a method in which the pressure-sensitive adhesive layer is laminated on the two layers together with the laminate layer,

(6) a method of laminating a pressure-sensitive adhesive layer and a base layer forming material such as a film or a laminate layer in two layers or in multiple layers,

And the like.

[Example]

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples at all. Tests and evaluation methods in Examples and the like are as follows. Unless otherwise noted, the term "part" means "part by weight" unless otherwise specified, and "%" means "% by weight" unless otherwise specified.

≪ Measurement of initial adhesive force to acrylic plate >

The pressure-sensitive adhesive sheet or the surface protection film was cut into a width of 20 mm and a length of 100 mm to obtain a sample for evaluation.

The pressure-sensitive adhesive layer side of the sample for evaluation was attached to an acrylic plate (trade name: Acrylite L manufactured by Mitsubishi Rayon Co., Ltd.) under an atmosphere of a temperature of 23 캜 and a humidity of 50% RH by reciprocating one 2.0 kg roller. After curing for 30 minutes in an atmosphere at a temperature of 23 캜 and a humidity of 50% RH, a peel angle of 180 °, a tensile rate of 300 mm / min (manufactured by Minebeagahashi Kikai K.K., trade name: TCM-1kNB) , And the adhesive strength was measured.

≪ Measurement of Adhesive Force at 70 캜 for 1 day after Acrylic Sheet >

An evaluation sample was prepared in the same manner as the initial adhesion to an acrylic plate, and the adhesion after storage at 70 ° C for 1 day was measured by the same method as the initial adhesion.

<Evaluation of early reworkability>

The pressure-sensitive adhesive sheet or the surface protection film was cut into a width of 20 mm and a length of 100 mm to obtain a sample for evaluation. The pressure-sensitive adhesive layer side of the evaluation sample was attached to an acrylic plate (manufactured by Mitsubishi Rayon, trade name: acrylite) under a condition of a temperature of 23 캜 and a humidity of 50% RH by a reciprocation of 2 kg roller.

After curing for 30 minutes in an atmosphere at a temperature of 23 DEG C and a humidity of 50% RH, the end portion of the sample for evaluation was picked up with the hand of the evaluator and peeled at a peeling angle of 100 to 120 deg. Mm / min to observe deformation of the substrate. The reworkability was evaluated according to the following criteria.

?: Peeled off without deformation of the substrate.

X: The substrate was deformed.

&Lt; Evaluation of adhesion reliability after elapse of time &

The pressure-sensitive adhesive sheet or the surface protective film was cut into a width of 20 mm and a length of 50 mm to obtain a sample for evaluation. An acryl plate (trade name: Acrylite L, manufactured by Mitsubishi Rayon Co., Ltd.) cut in a width of 25 mm in width and a length of 200 mm in the pressure-sensitive adhesive layer side of the evaluation sample in an atmosphere of a temperature of 23 캜 and a humidity of 50% RH, The longitudinal direction of the plate was aligned and attached by reciprocation of 2 kg roller.

After being stored at 70 DEG C for 1 day, the sample was allowed to stand for 30 minutes in an atmosphere of a temperature of 23 DEG C and a humidity of 50% RH. Thereafter, an acrylic plate with an evaluation sample was fixed inside the curved inner side with a width of 190 mm And the adhesion of the adhesion surface of the evaluation sample and the acrylic plate was observed. The adhesion reliability after the lapse of time was evaluated according to the following criteria.

○: No adhesion on the bonding surface between the sample for evaluation and the acrylic plate.

X: Flocculation occurred on the bonding surface between the evaluation sample and the acrylic plate.

&Lt; Evaluation of wettability &

The surface protective film was cut into 2.5 cm x 10.0 cm to obtain a test piece. The specimen was bonded manually to an acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: Acrylite L) at a speed of 10 m / min to confirm the presence or absence of air bubbles between the test piece and the acrylic plate. The evaluation was carried out according to the following criteria.

○: No bubbles.

B: A little bubbles were mixed, but they can be easily removed.

X: A large number of bubbles are mixed, and bubbles can not be easily removed.

<Evaluation of transparency>

(%) = (Td / Tt) x 100 (Td: diffusion transmittance, Tt: Tt) in accordance with JIS-K-7136 was measured using a haze meter HM-150 (manufactured by Murakami Shikisai Seisaku- Total light transmittance). The transparency was evaluated according to the following criteria.

○: Haze is less than 3%.

X: Haze exceeds 3%.

(Example 1)

As the polyol (A), 70 parts by weight of a polyol having two OH groups, that is, FREMINOL S4006 (manufactured by Asahi Kasei Corporation, Mn = 5500), and a polyol SANONIX GP-1500 having three OH groups 12 parts by weight of EDP-1100 (manufactured by ADEKA CORPORATION, Mn = 1100), which is a polyol having four OH groups, and 12 parts by weight of trimethylol (B) as a polyfunctional isocyanate compound (B) 12 parts by weight of a propane / tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by NIPPON POLYURETHANE CHEMICAL INDUSTRY CO., LTD.), A catalyst (trade name: Nasem ferric iron, Ethyl acetate was added as a diluting solvent so that the solid content concentration became 50% by weight, and the mixture was stirred with a disper to obtain a urethane pressure-sensitive adhesive composition. The obtained urethane pressure-sensitive adhesive composition was coated on a substrate "LM Mirror S10" (thickness 38 μm, manufactured by Doreya Co., Ltd.) comprising a polyester resin so as to have a thickness of 10 μm after drying with a fountain roll and dried under conditions of a drying temperature of 130 ° C. and a drying time of 30 seconds And dried.

Subsequently, the surface of the pressure-sensitive adhesive layer was covered with a release film obtained by surface-treating with a mold releasing agent, left at a temperature of 50 占 폚 for 12 hours and then left at room temperature (25 占 폚) for 1 hour to obtain a surface protective film (1). The obtained surface protective film 1 can also be used as a pressure sensitive adhesive sheet.

The evaluation results are shown in Table 1.

(Example 2)

A surface protective film (2) having a pressure-sensitive adhesive layer was obtained in the same manner as in Example 1 except that the amount of the polyfunctional isocyanate compound (B) used was changed to 24 parts by weight (NCO group / OH group = 1.0). The obtained surface protective film 2 can also be used as a pressure-sensitive adhesive sheet.

The evaluation results are shown in Table 1.

(Example 3)

As the polyol (A), 70 parts by weight of a polyol having two OH groups, that is, FREMINOL S4006 (manufactured by Asahi Kasei Corporation, Mn = 5500), and a polyol SANONIX GP-1500 having three OH groups 30 parts by weight of the polyfunctional isocyanate compound (B) (NCO group / OH group = 1.3) and 0.1 part by weight of the catalyst were used in the same manner as in Example 1, Except that, the procedure of Example 1 was repeated to obtain a surface protective film (3) having a pressure-sensitive adhesive layer. The obtained surface protective film 3 can also be used as a pressure sensitive adhesive sheet.

The evaluation results are shown in Table 1.

(Example 4)

As the polyol (A), 75 parts by weight of a polyol having two OH groups, that is, FRONINOL S4011 (manufactured by Asahi Kasei Corporation, Mn = 10000), a polyol having three OH groups, Except that the amount of the polyfunctional isocyanate compound (B) used was changed to 13 parts by weight (NCO group / OH group = 2.0) and the amount of the catalyst used was changed to 0.6 part by weight (manufactured by Kabushiki Kaisha, Mn = 5000) The procedure of Example 1 was otherwise repeated to obtain a surface protective film (4) having a pressure-sensitive adhesive layer. The obtained surface protective film 4 can also be used as a pressure-sensitive adhesive sheet.

The evaluation results are shown in Table 1.

(Example 5)

As the polyol (A), 50 parts by weight of FRONINOL S4011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having two OH groups, a polyol SANONIX GP-5000 Except that the amount of the multifunctional isocyanate compound (B) used was changed to 17 parts by weight (NCO group / OH group = 2.0) and the amount of the catalyst used was changed to 0.8 part by weight (manufactured by Kabushiki Kaisha, Mn = 5000) The procedure of Example 1 was otherwise repeated to obtain a surface protective film (5) having a pressure-sensitive adhesive layer. The obtained surface protective film 5 can also be used as a pressure-sensitive adhesive sheet.

The evaluation results are shown in Table 1.

(Example 6)

As the polyol (A), 25 parts by weight of FROMINOL S4011 (Mn = 10000, manufactured by Asahi Kasei Corporation), which is a polyol having two OH groups, and 4 parts by weight of SANONICS GP-5000 Except that the amount of the polyfunctional isocyanate compound (B) used was changed to 22 parts by weight (NCO group / OH group = 2.0) and the amount of the catalyst used was changed to 1.0 part by weight (manufactured by Kabushiki Kaisha, Mn = 5000) The procedure of Example 1 was otherwise repeated to obtain a surface protective film 6 having a pressure-sensitive adhesive layer. The obtained surface protective film 6 can also be used as a pressure-sensitive adhesive sheet.

The evaluation results are shown in Table 1.

(Comparative Example 1)

A surface protective film (C1) having a pressure-sensitive adhesive layer was obtained in the same manner as in Example 1 except that the amount of the polyfunctional isocyanate compound (B) used was changed to 30 parts by weight (NCO group / OH group = 1.3). The obtained surface protective film (C1) can also be used as a pressure-sensitive adhesive sheet.

The evaluation results are shown in Table 1.

(Comparative Example 2)

100 parts by weight of the polyfunctional isocyanate compound (B) was used in an amount of 4.4 parts by weight (manufactured by Asahi Glass Co., Ltd., Mn = 10000) (NCO group / OH group = 1.0) and the amount of the catalyst used was 0.39 part by weight, to obtain a surface protective film (C2) having a pressure-sensitive adhesive layer. The obtained surface protective film (C2) can also be used as an adhesive sheet.

The evaluation results are shown in Table 1.

(Example 7)

The surface protective film (1) obtained in Example 1 was adhered to a polarizing plate (trade name: "TEG1465DUHC" manufactured by Nitto Denka Kabushiki Kaisha) as an optical member to obtain an optical member to which a surface protective film was adhered.

(Example 8)

The surface protective film (1) obtained in Example 1 was adhered to a conductive film (trade name: "ELEKTRAST V270L-TFMP", manufactured by Nitto Denka Kabushiki Kaisha) as an electronic member to obtain an electronic member to which a surface protective film was adhered.

The pressure-sensitive adhesive sheet or surface-protective film of the present invention can be used for the purpose of protecting the surface by bonding to the surface of an optical member or an electronic member.

1: substrate layer
2: Pressure-sensitive adhesive layer
10: Adhesive sheet or surface protective film

Claims (15)

A pressure-sensitive adhesive comprising a polyurethane resin,
Assuming that the initial adhesive force immediately after bonding to the acrylic plate is A and the adhesive force after bonding at 70 DEG C x 1 day is B,
The initial adhesive force A is 0.001 N / 20 mm to 2.0 N / 20 mm,
Wherein the adhesive force B after 70 占 폚 for 1 day is 2.0 times or more the initial adhesive force A. The pressure-sensitive adhesive according to claim 1, wherein the polyurethane resin is a polyurethane resin obtained by curing a composition containing a polyol (A) having two or more OH groups and a polyfunctional isocyanate compound (B). The pressure-sensitive adhesive according to claim 2, wherein the polyol (A) is at least two kinds of polyols. 4. The pressure-sensitive adhesive according to claim 3, wherein the at least one polyol is a polyol having two OH groups and at least one of the polyols is a polyol having three or more OH groups. The pressure-sensitive adhesive according to claim 4, wherein the number average molecular weight Mn of the polyol having two hydroxyl groups is 6,000 or more and the number average molecular weight Mn of the polyol having three or more OH groups is 2000 or more. The polyol according to claim 4, wherein the polyol having two OH groups has a number average molecular weight Mn of less than 6000, and the number average molecular weight Mn of the polyol having three or more OH groups is less than 2000, Wherein the equivalent ratio of the NCO group and the OH group in the isocyanate compound (B) is less than 1.3 as the NCO group / OH group. The pressure-sensitive adhesive according to claim 2, wherein the polyol (A) contains at least 50% by weight of a polyol having two OH groups. The pressure-sensitive adhesive according to claim 1, wherein the amount of the catalyst (C) used for obtaining the polyurethane resin by curing is 0.01 parts by weight or more based on 100 parts by weight of the polyol (A). A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive according to claim 1 on at least one surface of a base layer. An optical member to which the pressure-sensitive adhesive sheet according to claim 9 is adhered. An electronic member to which the pressure-sensitive adhesive sheet according to claim 9 is adhered. A surface protective film having a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive according to claim 1 on one side of the base layer. The surface protecting film according to claim 12, wherein the surface protecting film is used for protecting the surface of the optical member or the electronic member. An optical member to which the surface protective film according to claim 13 is adhered. An electronic member to which the surface protecting film according to claim 13 is adhered.

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