KR101813846B1 - Urethane pressure-sensitive adhesive, manufacturing method thereof, pressure-sensitive adhesive sheet, and display - Google Patents

Abstract

The present invention provides a urethane pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer capable of coating a thick film and having excellent anti-wet heat resistance. The urethane pressure-sensitive adhesive of the present invention is characterized in that it comprises at least one polyol (a-1) excluding a polyether polyol having at least one EO group in one molecule and at least one polyether polyol (a- 2) and at least one polyisocyanate (b). In one embodiment, the urethane pressure-sensitive adhesive of the present invention may comprise a urethane prepolymer (A) and a β-diketone compound (X).

Description

TECHNICAL FIELD [0001] The present invention relates to a urethane adhesive, a production method thereof, a pressure-sensitive adhesive sheet, and a display,

The present invention relates to a urethane pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet and a display using the same.

A flat panel display such as a liquid crystal display (LCD) and an organic electroluminescence display (OELD), and a touch panel display in which a flat panel display and a touch panel are combined is used as a television (TV), a personal computer Telephones, and portable information terminals.

2. Description of the Related Art In recent years, various types of displays have been made thinner and thinner (thinner). Among the above, OELDs that can be expected to be thin and lightweight are attracting attention because they can obtain high brightness with low power. The OELD has a laminated structure in which a plurality of organic layers of one or more layers such as an organic light emitting layer and an organic charge transporting layer are laminated on a substrate. The OELD can also be made flexible by using a plastic film as a substrate.

In general, after using the organic EL device for a long period of time, characteristics such as light emission luminance, luminous efficiency, and uniformity of light emission tend to be lowered. It is considered that the characteristics of the organic EL device are reduced due to the thinness of the whole, the oxidation of the electrode due to oxygen and moisture, the denaturation of the organic substance, and the oxidative decomposition of the organic material due to the heat generation during driving. In addition, interface delamination may occur between the constituent elements due to the interface stress generated between the constituent elements due to the difference in thermal expansion coefficient of each constituent element. In order to solve such a problem, improvement of an encapsulation and a barrier layer has been studied. For example, it has been studied to construct a sealing agent, a barrier layer, and the like by a coating film.

There is a possibility that cracks, breakage, etc. occur in the sealing agent and the barrier layer made of the coating film due to impact and vibration generated in the manufacturing process, and they may cause deterioration of the organic EL element. Therefore, it is preferable that the thin film / fragile member is protected from impact, vibration and the like. BACKGROUND ART [0002] A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed on a base sheet is widely used as a surface protective sheet for protecting various optical members from damage and dust adhesion. However, It has not been reviewed. In the present specification, the "adhesive sheet" is a pressure-sensitive adhesive sheet (re-release pressure-sensitive adhesive sheet) having re-release properties.

Patent Document 1 discloses an acrylic pressure-sensitive adhesive containing an acrylate-based derivative, an acrylate-based derivative polymer, and a high molecular weight crosslinking agent (claim 1).

As means for increasing the impact resistance, thickening of the pressure-sensitive adhesive layer (thickening of the pressure-sensitive adhesive layer) may be considered, besides design of the pressure-sensitive adhesive composition. Patent Document 2 discloses an acrylic pressure-sensitive adhesive comprising a monofunctional urethane acrylate oligomer having a specific weight average molecular weight (Mw), an acrylate monomer, and a free radical photoinitiator as a pressure-sensitive adhesive capable of applying a thick film ). Patent Document 3 discloses a pressure-sensitive adhesive capable of applying a thick film, comprising a modified polyisocyanate and a polyol, wherein the modified polyisocyanate has a polyisocyanate having an NCO functional group, at least one terminal active hydrogen functional group per molecule and at least 6 ethyleneoxy groups (EO) unit, and the polyol includes a liquid polycarbonate diol. (Claim 1) The present invention provides a urethane pressure-sensitive adhesive comprising a modified polyisocyanate and a polyether compound.

Patent Document 4 discloses a pressure-sensitive adhesive sheet for fixing a fragile member comprising a pressure-sensitive adhesive layer in which a urethane pressure-sensitive adhesive containing a polyol and a polyfunctional isocyanate compound is cured by a so-called one-shot method (claim 1).

Patent Document 1: Japanese Patent Laid-Open Publication No. 2015-17278 Patent Document 2: Japanese Unexamined Patent Publication No. 144726 Patent Document 3: Japanese Patent Laid-Open Publication No. 2013-136731 Patent Document 4: Japanese Patent Laid-Open Publication No. 2014-172989

Patent Document 1 discloses that the acrylic pressure-sensitive adhesive contains a polymer having a high molecular weight at a relatively high concentration and has excellent impact absorbability even in a thin film (paragraph 0027). In general, when the pressure-sensitive adhesive sheet is adhered to an adherend such as an optical member, it is preferable that the pressure-sensitive adhesive layer spreads satisfactorily without wetting the air at the interface with the adherend. This property is also called " wetting property ". For example, the optical member may be inspected in a state in which the adhesive sheet is attached. In this case, the air entrained between the optical member and the pressure sensitive adhesive sheet interferes with the inspection. Generally, acrylic pressure-sensitive adhesives are not suitable for optical applications such as those which are less wettable than the urethane pressure-sensitive adhesive and are reluctant to curl air.

In Patent Document 2, it is described that the acrylic pressure-sensitive adhesive can have a uniform thickness with less hardening and shrinkage during light curing, thereby obtaining a pressure-sensitive adhesive sheet having excellent surface appearance (paragraph 0012). However, the acrylic pressure-sensitive adhesive has a similar problem as described above. In addition, in the acrylic pressure-sensitive adhesive described in Patent Document 2, the amount of light such as ultraviolet light reaching from the surface to the inside of the coating layer gradually decreases during the photo-curing of the coating layer (coating layer) In the layer, hardening unevenness in the thickness direction tends to easily occur. Further, it can not be said that suppression of the curing shrinkage is sufficient. Therefore, the thick film coating is not easy.

The urethane pressure-sensitive adhesive described in Patent Document 3 has high adhesive strength and is not suitable for re-peeling applications.

In Patent Document 4, nothing is mentioned about the ability to protect an adherend such as an optical member from impact or vibration, but in general, the one-shot method tends to deteriorate the surface smoothness of the adhesive layer due to curing shrinkage, Not suitable for anger.

In general, when the adhesive layer is exposed to a high temperature and high humidity environment, the adhesive layer may become cloudy (also referred to as whitening) due to the influence of moisture in the external environment, resulting in deterioration of the appearance. Therefore, it is preferable that the adhesive layer has good anti-wet heat resistance.

In general, the pressure sensitive adhesive sheet can protect an adherend such as an optical member from dust adhesion, but it is preferable that the pressure sensitive adhesive sheet used for various displays is antistatic in itself and has low dust adhesion.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a urethane pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer capable of coating a thick film and having excellent anti-wet heat resistance and an adhesive sheet using the same. The present invention also provides a urethane pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer capable of coating a thick film, having excellent anti-wet heat and whitening resistance, antistatic property and low dust adhesion, and a pressure- .

The inventors of the present invention have conducted intensive studies in order to achieve the above object, and have completed the present invention.

In the urethane pressure-sensitive adhesive of the first embodiment according to the present invention,

(A-1) excluding at least one polyether polyol having at least one ethyleneoxy (EO) group in one molecule and at least one polyether polyol having at least one ethyleneoxy (EO) group in a molecule Urethane prepolymer (A) which is a reaction product of a polyisocyanate (b-2) and at least one polyisocyanate (b)

beta -diketone compound (X).

In the urethane adhesive of the second embodiment of the present invention,

(A-1) excluding at least one polyether polyol having at least one ethyleneoxy (EO) group in one molecule and at least one polyether polyol having at least one ethyleneoxy (EO) group in a molecule -2) and at least one polyisocyanate (b), and a urethane prepolymer (A)

Fatty acid ester (B).

The urethane pressure-sensitive adhesive of the first embodiment is preferably a pressure-

(A-1) excluding at least one polyether polyol having at least one ethyleneoxy (EO) group in a molecule and at least one polyether polyol having at least one ethyleneoxy (EO) group in a molecule -2) and at least one polyisocyanate (b), and a urethane prepolymer (A)

can be produced by a production method of compounding? -diketone compound (X).

The pressure-sensitive adhesive sheet of the present invention comprises a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive of the first or second embodiment of the present invention.

The display of the present invention includes a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive of the first or second embodiment of the present invention.

In the present specification, the "ethyleneoxy group" is a group represented by the chemical formula "-CH ₂ CH ₂ O-" and may be briefly described as "EO group". Similarly, the ethylene oxide forming the EO group by the ring opening reaction (ring opening reaction) may be briefly described as " EO ".

In general, the sheet material (object) is referred to as a " tape ", " film ", or " sheet " depending on its thickness and width. In the present specification, the terms " sheet " is used as the term indicating the concept including them without particularly distinguishing them.

In the present specification, various physical properties are to be measured by the method described in [Examples] unless otherwise specified.

According to the present invention, there can be provided a urethane pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer capable of coating a thick film and having excellent anti-wet heat resistance, and an adhesive sheet using the same.

The pressure-sensitive adhesive according to the first embodiment of the present invention comprising the urethane prepolymer (A) and the? -Diketone compound (X) is excellent in heat resistance and anti-static properties, It is possible to form a pressure-sensitive adhesive layer with low dust adhesion.

1 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to a first embodiment of the present invention.
2 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to a second embodiment of the present invention.

"Urethane adhesive"

The urethane pressure-sensitive adhesive of the present invention comprises at least one specific urethane prepolymer (A).

The urethane pressure-sensitive adhesive of the first embodiment of the present invention comprises at least one specific urethane prepolymer (A) and at least one? -Diketone compound (X).

The urethane pressure-sensitive adhesive of the second embodiment of the present invention comprises at least one specific urethane prepolymer (A) and at least one fatty acid ester (B).

(Urethane prepolymer (A))

The urethane prepolymer (A) is a reaction product which can be obtained by a copolymerization reaction between various kinds of polyol (a) and at least one polyisocyanate (b). The urethane prepolymer (A) is a copolymer containing various kinds of monomer units derived from various polyols (a) and one or more polyisocyanates (b).

In the present invention, the polyols (a) of various kinds are obtained by reacting one or more polyols (a-1) excluding a polyether polyol having at least one ethyleneoxy (EO) group in one molecule and at least one ethyleneoxy (A-2) having at least one polyether polyol (EO) group.

≪ Polyol (a-1) >

The polyol (a-1) is any polyol excluding a polyether polyol having at least one EO group in one molecule. Examples of the polyol (a-1) include a polyacryl polyol, a polyester polyol, a polyether polyol having no EO group, a polycaprolactone polyol, a polycarbonate polyol, and a castor oil polyol. Among them, a polyester polyol, a polyether polyol having no EO group, a polycaprolactone polyol, and a polycarbonate polyol are preferable, and a polyester polyol and a polyether polyol having no EO group are more preferable.

The polyester polyol is a polyol having a polyester structure. The polyol is a polycondensation product of at least one acid component and at least one polyol component and can be obtained by an esterification reaction of at least one acid component with at least one polyol component.

Examples of the acid component of the raw material include polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, phthalic anhydride, isophthalic acid and trimellitic acid.

Examples of the polyol component of the starting material include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl- (Also referred to as glycol or diol) having two hydroxyl groups such as dimethylolheptane, 3'-dimethylolheptane, butylethylpentanediol, polyoxyethylene glycol, and polyoxypropylene glycol; glycerin, trimethylolpropane Trifunctional or higher polyols having three or more hydroxyl groups such as trimethylolpropane and pentaerythritol.

Generally, the polyether polyol is a polyol having a polyether structure, and is a ring-opening polymer of at least one active hydrogen-containing compound having two or more active hydrogens and at least one cyclic ether.

The polyether polyol used as the polyol (a-1) has no EO group. As the polyether polyol having no EO group, a cyclic ether which does not form an EO group is used as a raw material cyclic ether.

Examples of the active hydrogen-containing compound include a compound having a hydroxyl group, an amine, and a compound having a hydroxyl group and an NH group.

Examples of the compound having a hydroxyl group include compounds having two hydroxyl groups such as water and glycol (also referred to as a diol) (specifically, propylene glycol, 1,4-butanediol, neopentyl glycol, and butyl ethyl pentanediol) Functional polyols; trifunctional or higher polyols having three or more hydroxyl groups such as glycerin, trimethylol propane, and pentaerythritol; and the like.

Examples of the amine include polyamines such as ethylenediamine, isophoronediamine, and xylylenediamine.

Examples of the compound having a hydroxyl group and an NH group include N-aminoethylethanolamine and the like.

Examples of the cyclic ether which does not form an EO group include alkylene oxides (AO) excluding ethylene oxide (EO) such as propylene oxide and butylene oxide; and tetrahydrofuran.

As the polyether polyol having no EO group, an alkylene oxide adduct of an active hydrogen-containing compound (excluding an EO adduct) (also referred to as a polyoxyalkylene polyol) is preferable. Specific examples thereof include bifunctional polyalkylene glycols such as polypropylene glycol (PPG) and polytetramethylene glycol; and polyfunctional polyols having three or more functional groups such as alkylene oxide adducts of glycerin.

The polycaprolactone polyol is a polyol having a polyester structure and is a ring-opening polymer of at least one cyclic ester such as? -Caprolactone and? -Valerolactone. This polyol can be obtained by ring-opening polymerization of at least one cyclic ester.

The polycarbonate polyol is a polyol having a carbonate structure. The polyol can be obtained by a polycondensation of a polyol and a phosgene, a polycondensation of a polyol and a bisoxychloroformate of a dioxy compound, a polycondensation of a polyol and a carbonic acid diester, and a polycondensation of a polycarbonate of a polyol and a dioxy compound And so on.

The polyol (a-1) other than the polyether polyol may have an EO group, but it is preferable that the polyol (a-1) is a polyol having no EO group, regardless of the kind of the polyol (a-1). That is, the polyol (a-1) is at least one selected from the group consisting of a polyester polyol having no EO group, a polyether polyol having no EO group, a polycaprolactone polyol having no EO group, and a polycarbonate polyol having no EO group Is preferably a polyol of the species. Among them, a polyester polyol having no EO group and a polyether polyol having no EO group are more preferable.

The number average molecular weight (Mn) of the polyol (a-1) is not particularly limited, and preferable ranges are as follows.

The Mn of the polyester polyol is preferably 500 to 5,000, more preferably 1,000 to 4,000, and particularly preferably 1,000 to 3,000.

The Mn of the polyether polyol having no EO group is preferably 500 to 5,000, more preferably 1,000 to 4,000.

The Mn of the polycaprolactone polyol is preferably 500 to 5,000, more preferably 1,000 to 4,000, and particularly preferably 1,000 to 3,000.

The Mn of the polycarbonate polyol is preferably 500 to 5,000, more preferably 1,000 to 4,000, and particularly preferably 1,000 to 3,000.

With respect to each of the polyols, Mn is at least the lower limit, gelation of the urethane prepolymer (A) is effectively inhibited, and the cohesive force of the urethane prepolymer (A) becomes favorable because the upper limit is not exceeded.

≪ Polyether polyol (a-2) >

As the polyether polyol (a-2) having at least one EO group in one molecule, a compound (additional polymer) obtainable by addition polymerization of at least one cyclic ether containing ethylene oxide (EO) to the active hydrogen- . Examples of the cyclic ether other than the active hydrogen-containing compound and ethylene oxide (EO) are the same as the polyol (a-1).

Examples of the bifunctional polyether polyol having at least one EO group in one molecule include polyolefins obtained by addition polymerization of at least one alkylene oxide (AO) containing an active hydrogen-containing compound having two active hydrogen groups (EO) Alkylene glycols. Examples of the related polyalkylene glycols include polyethylene glycol (PEG) and the like.

The trifunctional or higher functional polyether polyol having at least one EO group in one molecule includes at least one alkylene oxide (AO) containing an ethylene oxide (EO) in an active hydrogen-containing compound having three or more active hydrogen groups, (Additional polymer) can be given. Examples of the trifunctional or higher functional polyether polyol having at least one EO group in one molecule include a glycerin EO adduct obtained by addition polymerization of at least one ethylene oxide (EO) to glycerin, at least one propylene oxide (PO) (Hereinafter also referred to as " glycerin polypropylene glycol end-terminated ethylene glycol modification ") obtained by addition polymerization of one or more ethylene oxide (EO) in this order.

The number average molecular weight (Mn) of the polyether polyol (a-2) having at least one EO group in one molecule is not particularly limited and is preferably 500 to 5,000, more preferably 1,000 to 5,000, particularly preferably 1,500 ~ 5,000. Mn is 500 or more, gelation of the urethane prepolymer (A) is effectively suppressed. Mn is not more than 5,000, the cohesive force of the urethane prepolymer (A) becomes favorable.

The urethane prepolymer (A) obtained by using the polyether polyol (a-2) having at least one EO group in one molecule is liable to be relatively hardened. Therefore, after the pressure-sensitive adhesive of the present invention is coated on the base sheet, the coating layer is cured relatively quickly, so that it is easy to coat the thick film. In addition, even when the thick film is coated, the coated layer is cured relatively quickly. Therefore, the coated layer and the adhesive layer are affected by the mechanical stress and the like, which are caused by hot air during heating and drying of the coated layer, It is difficult to receive. Therefore, defects such as rolls and warpage are suppressed, and a pressure-sensitive adhesive layer having good surface smoothness can be formed. The pressure-sensitive adhesive layer can thicken the pressure-sensitive adhesive layer, so that the pressure-sensitive adhesive layer is excellent in impact resistance and excellent in the function of protecting an adherend such as various optical members from impact and vibration.

In general, the pressure-sensitive adhesive layer may become cloudy (whitened) when exposed to a high temperature and high humidity environment. The EO group is a hydrophilic group. By using the urethane prepolymer (A) obtained by using the polyether polyol (a-2) having at least one EO group in one molecule, hydrophilicity of the pressure-sensitive adhesive layer can be improved and heat whitening can be suppressed. The migration (migration) of moisture between the adhesive layer and the external environment is apt to occur due to the improvement of the hydrophilic property of the adhesive layer, so that even if moisture penetrates into the adhesive layer from the outside, moisture is likely to be discharged from the adhesive layer to the external environment, It is considered that the water content in the layer can be kept relatively low.

Further, the urethane prepolymer (A) obtained by using the polyether polyol (a-2) having at least one EO group in one molecule has a little conductivity, so that the pressure-sensitive adhesive layer using the urethane prepolymer has relatively low surface resistance, You can have a little. However, the inventors of the present invention have found that the urethane prepolymer (A) alone can not exhibit antistatic properties to such an extent that the adhesion of the adhesive layer can be effectively suppressed. When the urethane prepolymer (A) and the? -Diketone compound (X) are used in combination, the surface resistance value of the pressure-sensitive adhesive layer is effectively lowered and the antistatic property is effectively exhibited, and the surface of the adherend after peeling off the pressure- The adhesion can be effectively suppressed.

As the polyol (a-1), any of a bifunctional polyol having two hydroxyl groups and a trifunctional or more polyol having three or more hydroxyl groups may be used. These may be used in combination.

Similarly, as the polyol (a-2), any of a bifunctional polyol having two hydroxyl groups and a trifunctional or more polyol having three or more hydroxyl groups may be used. These may be used in combination.

In general, the bifunctional polyol has a two-dimensional crosslinking property and can impart appropriate flexibility to the pressure-sensitive adhesive layer. The polyol having three or more functionalities has three-dimensional crosslinkability, and the hardness can be imparted to the adhesive layer.

By selecting the number of hydroxyl groups of at least one polyol (a-1) and the number of hydroxyl groups of at least one polyol (a-2), properties such as adhesion, cohesion, and re-peelability of the urethane pressure- have. It is preferable that at least one of the various kinds of polyols (a) is a trifunctional or more polyol because it is easy to achieve both adhesion and re-peeling property.

The mass ratio of the at least one polyether polyol (a-1) to the at least one polyether polyol (a-2) is not particularly limited. The total amount of at least one polyether polyol (a-1) and at least one polyether polyol (a-2) is 100 parts by mass. The amount of the at least one polyether polyol (a-1) is preferably from 0 to 50 parts by mass, more preferably from 20 to 50 parts by mass. The amount of the at least one polyether polyol (a-2) is preferably 50 parts by mass or more and less than 100 parts by mass, and more preferably 50 to 80 parts by mass. The amount of the at least one polyether polyol (a-2) is 50 parts by mass or more, whereby the anti-wet heat and anti-static properties can be effectively exhibited. Since the amount of the at least one polyol (a-1) is more than 0 part by mass, the effect of the thick film coating can be effectively exhibited.

≪ Polyisocyanate (b) >

Examples of the polyisocyanate (b) include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic (alicyclic) polyisocyanates.

Examples of the aromatic polyisocyanate include aromatic polyisocyanates such as 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4, 6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4, 4'-toluene diisocyanate, 4'-diphenyl ether diisocyanate, 4,4 ', 4 "-triphenylmethane triisocyanate, omega, diisocyanate-1,3-dimethylbenzene, omega, omega-diisocyanate- -Dimethylbenzene,?,? '- diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate.

Examples of the aliphatic polyisocyanate include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, , Dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4- Cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylene bis (cyclohexyl isocyanate), and 1,4-bis (isocyanate methyl) cyclohexane. have.

In addition, examples of the polyisocyanate (b) include trimethylolpropane adduct, biuret, and trimer of the above polyisocyanate (the trimer is an isocyanurate ring). ) And the like.

As the polyisocyanate (b), an aliphatic polyisocyanate and an alicyclic polyisocyanate are preferable, and an aliphatic polyisocyanate is more preferable.

(A) (specifically, a combination of at least one polyol (a-1) and at least one polyether polyol (a-2)) in the polymerization of the urethane prepolymer (A) The above polyisocyanate (b) means a polyisocyanate (b) having a functional group ratio (NCO / OH ratio) of the molar number of hydroxyl groups (OH) in the various polyols (a) to the number of moles of isocyanate (NCO) groups in one or more polyisocyanates ) Is in the range of 0.5 to 0.9.

<Catalyst>

In the polymerization of the urethane prepolymer (A), one or more kinds of catalysts may be used, if necessary. As the catalyst, known catalysts can be used, and tertiary amine compounds and organometallic compounds can be mentioned.

Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo (5,4,0) undec (5,4,0) undecene-7 -7-ene, DBU).

Examples of the organometallic compounds include tin compounds and non-saponified compounds.

Examples of the tin compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dioctyltin dilaurate, dibutyltin Diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride , Tributyltin trichloroacetate, and 2-ethylhexanoate (Tin (II) 2-Ethylhexanoate).

Examples of non-saponified compounds include titanium-based compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxy titanium trichloride; lead oleate (lead), lead (II) 2-ethylhexanoate, Lead, and lead naphthenate; iron-based compounds such as iron 2-ethylhexanoate and iron acetylacetonate; and cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate ; Zinc-based compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and other metal-based compounds such as zirconium naphthenate and bismuth carboxylate.

When the reactivities of various polyols (a) are different from each other, gelation or clouding of the reaction solution tends to occur easily in a single catalyst system due to the difference in reactivity. In this case, by using two or more kinds of catalysts, it is easy to control the reaction (for example, the reaction rate), and the above problem can be solved, and the degree of freedom of the polyol (a) is also increased. That is, in the present invention, it is preferable to use two or more catalysts.

The combination of two or more catalysts is not particularly limited, and examples thereof include a tertiary amine / organometallic system, a tin system / non-silicon system, and a tin system / tin system. Preferably a tin base / tin base, more preferably dibutyltin dilaurate / 2-ethylhexanoate tin.

The mass ratio of 2-ethylhexanoate tin / dibutyltin dilaurate is not particularly limited, and is preferably more than 0 and less than 1, more preferably 0.2 to 0.6. If the mass ratio is less than 1, the balance of the catalytic activity is good and the gelation can be effectively suppressed.

The amount of the at least one catalyst to be used is not particularly limited and is preferably 0.01 to 1% by mass, based on the total amount of the polyol (a) and the polyisocyanate (b).

<Solvent>

In the polymerization of the urethane prepolymer (A), one or more kinds of solvents may be used, if necessary. As the solvent, known ones can be used, and ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; aromatic hydrocarbons such as toluene and xylene. From the viewpoints of the solubility of the urethane prepolymer (A) and the boiling point of the solvent, ethyl acetate and toluene are preferred.

<Polymerization method>

The polymerization method of the urethane prepolymer (A) is not particularly limited, and known polymerization methods such as bulk polymerization (bulk polymerization) and solution polymerization can be applied.

The order of polymerization is not particularly limited,

Step 1) a step of batchwise mixing and reacting various kinds of polyol (a), at least one polyisocyanate (b), optionally at least one catalyst, and optionally at least one solvent;

Step 2) A procedure of mixing various kinds of polyol (a), optionally at least one catalyst, and optionally at least one solvent, and adding at least one polyisocyanate (b) have.

Since the reaction is easy to control, step 2) is preferable.

The reaction temperature in the case of using the catalyst is preferably less than 100 占 폚, more preferably 85 to 95 占 폚. If the reaction temperature is less than 100 캜, it is easy to control the reaction rate and crosslinking structure, and the urethane prepolymer (A) having a desired molecular weight is easily produced.

When the catalyst is not used, the reaction temperature is preferably not lower than 100 ° C, more preferably not lower than 110 ° C, and the reaction time is preferably not lower than 3 hours.

The urethane prepolymer (A) has a weight average molecular weight (Mw) of preferably from 30,000 to 500,000, more preferably from 50,000 to 400,000, and a molecular weight distribution (Mw / Mn ) Is preferably 4 to 12, more preferably 6 to 10.

(? -diketone compound (X))

The pressure-sensitive adhesive of the present invention may contain at least one? -Diketone compound (X) in the first embodiment.

The β-diketone compound (X) is not particularly limited and includes, for example, 2,2,4-pentanedione, 3-methyl-2,4-pentanedione, 2,4- Heptanedione, 2,5-heptanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 1,3-heptanedione, 2, 4-hexanedione, 2, 4-octanedione, 2,2,7,tetramethyl-3, 5-octanedione, , 1-phenyl-1, 3-butanedione, and spirodecanedione. Among them, 2, 4-pentanedione and 2, 2-dimethyl-3, 5-hexanedione are preferred.

The β-diketone compound (X) has a dielectric polarity because it is easy to form an enol form among the keto-enol tautomers and accordingly has a small conductivity. Therefore, the pressure-sensitive adhesive layer containing this compound has a relatively low surface resistance value and can have a little antistatic property. However, the inventors of the present invention have found that the antistatic property of the? -Diketone compound (X) alone can not exhibit an antistatic property to such an extent that the adhesion of the adhesive layer can be effectively suppressed. When the urethane prepolymer (A) having at least one EO group is used in combination with the? -Diketone compound (X), the surface resistance value of the pressure-sensitive adhesive layer is effectively lowered and the antistatic property is effectively exhibited, The adhesion can be effectively suppressed.

The amount of the at least one? -Diketone compound (X) to be added is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 10 parts by mass, more preferably 0.05 to 10 parts by mass, relative to 100 parts by mass of the at least one urethane prepolymer (A) Preferably 0.1 to 5 parts by mass, and most preferably 0.5 to 5 parts by mass. When the addition amount is 0.01 parts by mass or more, the effect of suppressing dust adhesion of the pressure-sensitive adhesive layer can be effectively exhibited. When the addition amount is 10 parts by mass or less, the amount of the urethane prepolymer (A), which is the main effective ingredient of the original necessary pressure-sensitive adhesive, is sufficiently secured, and the required performance as a pressure-sensitive adhesive is secured.

(Fatty acid ester (B))

The pressure-sensitive adhesive of the present invention may contain at least one kind of fatty acid ester (B) in the second embodiment. The fatty acid ester (B) acts as a plasticizer to improve the wetting property of the adhesive layer. The fatty acid ester (B) can also be obtained by increasing the hydrophobicity of the surface layer on the adherend such as the optical member of the adhesive layer, in particular, the adhesive layer to prevent the moisture penetration from the external environment into the adhesive layer when the adhesive sheet is exposed to a high- (Whitening) of the adhesive layer can be suppressed.

The fatty acid ester (B) is not particularly restricted but includes esters obtainable by reacting a monobasic acid or a polybasic acid having 8 to 18 carbon atoms with a branched alcohol having a carbon number of 18 or less, an unsaturated fatty acid having 14 to 18 carbon atoms, Esters obtainable by the reaction of an alcohol are preferable.

Examples of the ester that can be obtained by the reaction of a monobasic acid or a polybasic acid having 8 to 18 carbon atoms and a branched alcohol having 18 or less carbon atoms include isostearyl laurate, isopropyl myristate, isocetyl myristate, Octyldodecyl stearate, isostearyl palmitate, isocetyl stearate, octyldodecyl oleate, diisostearyl adipate, diisocetyl sebacate, trimellitic trioleate, and triisostearyl trimellitate. . Of these, isopropyl myristate, isocetyl myristate, and octyldodecyl myristate are preferable, and isopropyl myristate is particularly preferable.

Examples of the unsaturated fatty acid having 14 to 18 carbon atoms include misteroleic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid and isostearic acid. Examples of alcohols having four or less hydroxyl groups include ethylene glycol, propylene glycol, glycerin, trimethylol propane, pentaerythritol, and sorbitan.

The number average molecular weight (Mn) of the fatty acid ester (B) is not particularly limited, and is preferably 200 or more, and preferably 600 or less, from the viewpoint of improving the wetting speed.

The amount of the at least one fatty acid ester (B) to be added is not particularly limited and is preferably 5 to 50 parts by mass, more preferably 20 to 40 parts by mass, relative to 100 parts by mass of the at least one urethane prepolymer (A) . When the addition amount is 5 parts by mass or more, the addition effect (wetting property improving effect) of the fatty acid ester (B) can be effectively exhibited. When the addition amount is 50 parts by mass or less, the amount of the urethane prepolymer (A), which is the main effective ingredient of the originally necessary pressure-sensitive adhesive, is sufficiently secured, and the required performance as a pressure-sensitive adhesive is secured.

The urethane pressure-sensitive adhesive of the present invention may be a third embodiment in which the first embodiment and the second embodiment are combined. That is, the urethane pressure-sensitive adhesive of the present invention may be the third embodiment including the urethane prepolymer (A), the β-diketone compound (X) and the fatty acid ester (B).

(Isocyanate curing agent (I))

The pressure-sensitive adhesive of the present invention may contain one or more isocyanate curing agents (I) as required. From the pressure-sensitive adhesive of the present invention, the urethane prepolymer (A) is cured by the isocyanate curing agent (I) to finally become a cured film.

As the isocyanate curing agent (I), known ones can be used, and the compounds exemplified as the polyisocyanate (b) which is the material of the urethane prepolymer (specifically, aromatic polyisocyanate, aliphatic polyisocyanate, aromatic aliphatic polyisocyanate, alicyclic Polyisocyanate, and trimethylolpropane duct / burette / trimer thereof) can be used.

The content of the at least one isocyanate curing agent (I) in the urethane pressure-sensitive adhesive of the present invention is not particularly limited and is preferably 3 to 30 parts by mass, more preferably 3 to 30 parts by mass, per 100 parts by mass of the at least one urethane prepolymer (A) 10 to 20 parts by mass. When the content is 3 parts by mass or more, the cohesive strength of the pressure-sensitive adhesive layer becomes good, and when the content is 30 parts by mass or less, the pressure-sensitive adhesive layer has good adhesion.

(Hardening accelerator)

The pressure-sensitive adhesive of the present invention may contain one or more curing accelerators as required. As the curing accelerator, known catalysts can be used, and catalysts exemplified by the synthesis of the urethane prepolymer (A) can be exemplified.

The amount of the one or more curing accelerators to be added is not particularly limited and is preferably 0.0005 to 0.5 parts by mass, more preferably 0.001 to 0.1 parts by mass, per 100 parts by mass of the urethane prepolymer (A) from the viewpoint of promoting effective curability Particularly preferably 0.003 to 0.05 part by mass, and most preferably 0.005 to 0.03 part by mass.

(solvent)

The pressure-sensitive adhesive of the present invention may contain at least one solvent as required. As the solvent, known ones can be used, and examples thereof include acetone, methyl ethyl ketone, ethyl acetate, toluene, and xylene. From the viewpoints of the solubility of the urethane prepolymer (A) and the boiling point of the solvent, ethyl acetate, toluene and the like are particularly preferable.

(Other optional components)

The pressure-sensitive adhesive of the present invention may contain one or more other optional components as needed, so long as the effect of the present invention is not impaired. Other optional components may include any resin other than the urethane prepolymer (A), a curing retarder, a filler, a metal powder, a colorant, a foil, a softener, a conductive agent, an antioxidant, A surface lubricant, a leveling agent, a corrosion inhibitor, a heat stabilizer, a polymerization inhibitor, a defoaming agent, and a lubricant.

<Filler>

Examples of the filler include talc, calcium carbonate, and titanium oxide.

<Antioxidant>

Examples of the antioxidant include a radical chain inhibitor (primary antioxidant) and a peroxide releasing agent (secondary antioxidant). Examples of the radical chain inhibitor (primary antioxidant) include phenol-based antioxidants and amine-based antioxidants. Examples of the peroxide releasing agent (secondary antioxidant) include sulfur-based antioxidants and phosphorus-based antioxidants.

Examples of the phenol-based antioxidant include monophenol-based, bisphenol-based, and polymer-based phenol-based antioxidants. Examples of the monophenol antioxidant include 2, 6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6- 3, 5-di-t-butyl-4-hydroxyphenyl) propionate.

Examples of the bisphenol-based antioxidant include 2, 2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'- (3-methyl-6-t-butylphenol), 4,4'-butylidenebis Dimethyl-2- [β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] .

Examples of the polymer type phenolic antioxidant include 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl- (3, 5'-di-t-butyl-4'-hydroxyphenyl) propionate ] Methane, bis [3,3'-bis- (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, and 1,3,5- -Butyl-4'-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione and tocopherol. For example, IRGANOX L 135 (manufactured by BASF) is preferable because of its good compatibility with the urethane prepolymer (A).

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

Examples of the phosphorus antioxidant include triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite.

&Quot; Method for producing urethane pressure-sensitive adhesive &quot;

The urethane pressure-sensitive adhesive of the present invention can be produced by applying a known method.

The urethane pressure-sensitive adhesive of the first embodiment is preferably a pressure-

(A-1) excluding at least one polyether polyol having at least one ethyleneoxy group in one molecule, at least one polyether polyol (a-2) having at least one ethyleneoxy group in one molecule and one or more polyether polyols Urethane prepolymer (A) obtained by reacting polyisocyanate (b)

can be produced by a production method of compounding? -diketone compound (X).

The urethane pressure-sensitive adhesive of the second embodiment is preferably a pressure-

(A-1) excluding at least one polyether polyol having at least one ethyleneoxy group in one molecule, at least one polyether polyol (a-2) having at least one ethyleneoxy group in one molecule and one or more polyether polyols (A) obtained by reacting the above polyisocyanate (b) with a urethane prepolymer

And fatty acid ester (B).

&Quot; Adhesive sheet &quot;

The pressure-sensitive adhesive sheet of the present invention comprises a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive of the present invention. The pressure-sensitive adhesive sheet of the present invention preferably includes a pressure-sensitive adhesive layer comprising a base sheet and a cured product of the pressure-sensitive adhesive of the present invention. The adhesive layer can be formed on one or both surfaces of the substrate sheet. If necessary, the exposed surface of the adhesive layer can be covered with a release sheet (also referred to as release liner). Further, the release sheet is peeled off when the pressure-sensitive adhesive sheet is adhered to the adherend.

1 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet of a first embodiment according to the present invention. In Fig. 1, reference numeral 10 denotes an adhesive sheet, reference numeral 11 denotes a base sheet, reference numeral 12 denotes an adhesive layer, and reference numeral 13 denotes a release sheet. The adhesive sheet 10 is a single-sided adhesive sheet having an adhesive layer formed on the end face of the base sheet.

2 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to a second embodiment of the present invention. 2, reference numeral 20 denotes an adhesive sheet, reference numeral 21 denotes a base sheet, reference numerals 22A and 22B denote adhesive layers, and reference numerals 23A and 23B denote peeling sheets.

The substrate sheet is not particularly limited, and examples thereof include a resin sheet, paper, metal foil and the like. The base sheet may be a laminated sheet in which any one or more layers are laminated on at least one side of the base sheet. The side of the substrate sheet on which the adhesive layer is formed may be subjected to a reverse adhesion (easy adhesion) treatment such as corona discharge treatment and application of an anchor coating agent, if necessary.

Examples of the resin constituting the resin sheet include, but are not limited to, ester resins such as polyethylene terephthalate (PET); olefin resins such as polyethylene (PE) and polypropylene (PP); vinyl resins such as poly And the like; urethane-based resins (including foams); combinations of these; and the like.

The thickness of the resin sheet excluding the polyurethane sheet is not particularly limited, and is preferably 15 to 300 占 퐉. The thickness of the polyurethane sheet (including the foam) is not particularly limited, and is preferably 20 to 50,000 탆.

The paper is not particularly limited, and examples thereof include plain paper, coated paper, and art paper.

The constituent metal of the metal foil is not particularly limited, and examples thereof include aluminum, copper, and combinations thereof.

The release sheet is not particularly limited, and a known release sheet on which a known release treatment such as application of a release agent is applied to the surface of a resin sheet or paper can be used.

The pressure-sensitive adhesive sheet can be produced by a known method.

First, the pressure-sensitive adhesive of the present invention is coated on the surface of the substrate sheet to form a coating layer made of the urethane pressure-sensitive adhesive of the present invention. As a coating method, known methods can be applied, and examples thereof include a roll coating method, a comma coating method, a die coating method, a reverse coating method, a silk screen processing method, and a gravure coating method.

Next, the coating layer is dried and cured to form an adhesive layer comprising a cured product of the urethane pressure-sensitive adhesive of the present invention. The heating and drying temperature is not particularly limited, and is preferably about 60 to 150.

Then, if necessary, the release sheet is attached to the exposed surface of the adhesive layer by a known method.

By performing the above procedure, a single-sided pressure-sensitive adhesive sheet can be produced.

The double-sided pressure-sensitive adhesive sheet can be produced by carrying out the above operation on both sides.

In contrast to the above method, the pressure-sensitive adhesive of the present invention is coated on the surface of the release sheet to form a coating layer comprising the pressure-sensitive adhesive of the present invention, and then the coating layer is dried and cured to obtain a pressure- And the base sheet may be laminated on the exposed surface of the adhesive layer at the end.

The urethane pressure-sensitive adhesive of the present invention can be used suitably for thin film coating or thick film coating, and the degree of freedom in designing the thickness of the pressure-sensitive adhesive layer is higher than in the past. The thickness of the pressure-sensitive adhesive layer can be appropriately designed according to the use of the pressure-sensitive adhesive sheet, and may be a conventional level (5 to 30 占 퐉) or a thick film level of 30 占 퐉 or more. By thickening the pressure-sensitive adhesive layer, it is possible to form an pressure-sensitive adhesive layer excellent in impact resistance and excellent in the function of protecting the adherend from shock and vibration. The upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited and is about 200 占 퐉 because a pressure-sensitive adhesive layer having a good surface smoothness can be formed. From the viewpoints of improvement in impact resistance and surface smoothness, the thickness of the pressure-sensitive adhesive layer is preferably 30 to 200 占 퐉, more preferably 40 to 150 占 퐉, and particularly preferably 50 to 150 占 퐉. In the present specification, the &quot; thickness of the adhesive layer &quot; is the thickness after drying unless otherwise specified.

As described above, by using the pressure-sensitive adhesive of the first embodiment according to the present invention comprising the urethane prepolymer (A) and the? -Diketone compound (X), the surface resistance value of the pressure-sensitive adhesive layer is reduced, So that dust adhesion of the pressure-sensitive adhesive sheet can be effectively suppressed. The antistatic property can be evaluated by the surface resistance value.

The surface resistance value of the pressure-sensitive adhesive layer which can be obtained by using the urethane pressure-sensitive adhesive of the present invention is preferably less than 1.0 × 10 ¹¹ (Ω / □). If the surface resistance value is at this level, dust adhesion is effectively suppressed. The &quot; surface resistance value &quot; can be measured by the method described in [Example].

The adhesive sheet of the present invention can be used in the form of a tape, a label, a seal, a double-sided tape or the like. The pressure-sensitive adhesive sheet of the present invention is suitably used as a surface protective sheet, a cosmetic sheet, a non-slip sheet, and the like.

The pressure-sensitive adhesive sheet of the present invention is suitably used as a surface protective sheet such as various displays (such as a flat panel display and a touch panel display) and substrates and optical members manufactured or used in such a manufacturing process.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to provide a urethane pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer capable of coating a thick film and having excellent anti-wet heat resistance, and an adhesive sheet using the same.

The pressure-sensitive adhesive of the first embodiment according to the present invention, which comprises the urethane prepolymer (A) and the? -Diketone compound (X), is capable of thick coating, It is possible to form a pressure-sensitive adhesive layer with low dust adhesion.

The pressure-sensitive adhesive of the second embodiment according to the present invention, which comprises the urethane prepolymer (A) and the fatty acid ester (B), forms a pressure-sensitive adhesive layer having a good wetting property, .

"display"

The display of the present invention includes a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive of the present invention. The display of the present invention may preferably include a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive of the present invention.

Examples of the display include a flat panel display such as a liquid crystal display (LCD) and an organic electroluminescence display (ELD), and a touch panel display in which a related flat panel display and a touch panel are combined.

Example

Hereinafter, Synthesis Examples, Examples according to the present invention, and Comparative Examples will be described. Unless specifically stated otherwise in the following description, "part" means "part by mass" and "%" means "% by mass".

[Measurement of Mw, Mn and Mw / Mn]

The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) were measured by gel permeation chromatography (GPC). The measurement conditions are as follows. Further, both Mw and Mn are in terms of polystyrene conversion.

<Measurement Conditions>

Device: Three serial connection is made between SHIMADZU Prominence (manufactured by Shimadzu Corporation), column: SHODEX LF-804 (manufactured by SHOWA DENKO K.K.), detector: differential refraction index detector,

Solvent: Tetorohydrofuran (THF),

Flow rate: 0.5 mL / min,

Solvent temperature: 40,

Sample density: 0.1%

Sample injection amount: 100 (intact ~).

[material]

The materials used are as follows.

&Lt; Polyol (a-1) &gt;

(a-1-1): Kuraray Polyol P-1010 (product of KURARAY CO., LTD.), bifunctional polyester polyol having no EO group, Mn1000,

(a-1-2): Kuraray Polyol P-2010 (product of KURARAY CO., LTD.), bifunctional polyester polyol having no EO group, Mn2000,

(a-1-3): Kuraray Polyol P-3010 (product of KURARAY CO., LTD.), bifunctional polyester polyol having no EO group, Mn3000,

(a-1-4): SANNIX GP-1500 (manufactured by Sanyo Chemical Industries, Ltd.), a trifunctional polyether polyol having no EO group, Mn1500,

(a-1-5): SANNIX PP-2000 (manufactured by Sanyo Chemical Industries, Ltd.), bifunctional polyether polyol having no EO group, Mn2000,

(a-1-6): SANNIX GP-3000 (manufactured by Sanyo Chemical Industries, Ltd.), trifunctional polyether polyol having no EO group, Mn3000,

(a-1-7): PLACCEL 220 N (manufactured by Daicel Corporation), bifunctional polycaprolactone polyol having no EO group, Mn2000, hydroxyl number 2,

(a-1-8): Desmophen 2020 E (manufactured by Covestro Japan Ltd.), bifunctional polycarbonate polyol having no EO group, Mn2000, hydroxyl number 2,

(a-1-9): PREMINOL S4006 (manufactured by ASAHI GLASS CO., LTD.), bifunctional polyether polyol having no EO group, Mn5500,

(a-1-10): EDP-1100 (manufactured by ADEKA CORPORATION), tetrafunctional polyether polyol having no EO group, Mn1100, hydroxyl number 4.

<Polyether polyol (E-2) having EO group>

(a-2-1) Adeka polyether AM-302 (product of ADEKA CORPORATION), trifunctional polyether polyol, glycerin PO.EO adduct, Mn3000, hydroxyl number 3,

(a-2-2) Adeka polyether GR-3308 (product of ADEKA CORPORATION), trifunctional polyether polyol, glycerin PO.EO adduct, Mn3400, hydroxyl number 3.

&Lt; Polyisocyanate (b) &gt;

(b-1): hexamethylene diisocyanate (product of TOSOH CORPORATION),

(b-2): Takenate (registered trademark) 500 (manufactured by Mitsui Chemicals, Inc.), 1,3-xylylene diisocyanate.

<Fatty acid ester (B)>

(B-1): NIKKOL IPP (product of Nikko Chemicals Co., Ltd.), isopropyl palmitate,

(B-2): NIKKOL IPM-100 (product of Nikko Chemicals Co., Ltd.), isopropyl myristate.

&Lt;? -Diketone compound (X)

(X-1): 2, 4-pentanedione,

(X-2): 2,2-dimethyl-3, 5-hexanedione.

&Lt; Isocyanate curing agent (I) &gt;

(I-1): CORONATE HL (manufactured by TOSOH CORPORATION), hexamethylene diisocyanate / trimethylolpropane adduct,

(I-2) Desmodur N-3300 (a product of Covestro Japan Ltd., manufactured by Sumitomo Bayer Urethane Co., Ltd.), hexamethylene diisocyanate / isocyanurate,

(I-3): CORONATE L (manufactured by TOSOH CORPORATION), toluene diisocyanate / trimethylolpropane.

[Synthesis of urethane prepolymer (A)]

(Synthesis Example 1)

50 parts of a polyester polyol (a-1-1) and 50 parts of a polyether polyol (a-2-a) having at least one EO group were placed in a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel. 1). Here, 650 parts of toluene was added. Further, 0.25 part of dibutyltin dilaurate and 0.1 part of 2-ethylhexanoic acid tin were added as a catalyst. The temperature was gradually raised to 90 under nitrogen and polyisocyanate (b-1) was added dropwise in an amount (48 parts) such that the NCO / OH ratio (functional group ratio) became 0.6, and the reaction was carried out for 2 hours. The urethane prepolymer (A-1) solution (nonvolatile component: 60%) was obtained by confirming disappearance of the residual isocyanate group by infrared absorption (IR) spectrum and then cooling the reaction solution to terminate the reaction. The weight average molecular weight (Mw) of the resulting urethane prepolymer (A-1) was 78,000.

The types of the polyol (a) and the polyisocyanate (b) used, the blending ratio thereof, and the Mw of the urethane prepolymer obtained are shown in Table 1-1. In Table 1-1, the unit of the amount of the polyol (a) is [parts] and the blending amount of the polyisocyanate (b) is represented by the NCO / OH ratio (functional group ratio) 5).

The amount of polyisocyanate (b-1) was calculated in accordance with the following calculation formula (the same applies to other synthesis examples).

(Quantity of (b-1)) [Part] =

(NCO / OH ratio) x (molecular weight of (b-1)) / (number of NCO of (b-1)

× (number of hydroxyl groups in (x1-1)) / ((x1-1)) × (number of hydroxyl groups in x1-1)

(Number of hydroxyl groups in (x2-1)) / ((x2-1)) x (number of hydroxyl groups in (x2-1))]

= 0.6 x 168.2 / 2 x (50/1000 x 2 + 850/3000 x 3)

= 48

(Synthesis Examples 2 to 22)

In Synthesis Examples 2 to 22, in the same manner as in Synthesis Example 1, except that the kind of the polyol (a) and the polyisocyanate (b) used and the blending ratio thereof were changed as shown in Tables 1-1 to 1-5, Urethane prepolymers (A-1) to (A-19) and comparative urethane prepolymers (D-1) to (D-3) were obtained. Mw of the obtained urethane prepolymer and non-volatile matter concentration of the urethane prepolymer solution are shown in Tables 1-1 to 1-5 in each synthesis example.

[Example 1]

100 parts of the urethane prepolymer (A-1) obtained in Synthesis Example 1, 30 parts of the fatty acid ester (B-1), 0.3 parts of the antioxidant IRGANOX L 135 (product of BASF SE), ultraviolet absorbent TINUVIN 571 , 0.3 part of a light stabilizer (product of BASF SE), 0.3 part of a light stabilizer "TINUVIN 765" (product of BASF SE), 15 parts of an isocyanate curing agent (I-1) and 100 parts of ethyl acetate as a solvent were mixed and stirred with a disper A urethane pressure-sensitive adhesive was obtained. The amount of each material except for the solvent represents the nonvolatile matter equivalent value (the same applies to other examples and comparative examples). Table 2-1 shows the types of materials used and their blending ratios.

[Examples 2 to 26]

In Examples 2 to 26, a urethane pressure-sensitive adhesive was obtained in the same manner as in Example 1, except that the kind of the material used and the blending ratio were changed as shown in Tables 2-1 to 2-4 and Tables 3-1 to 3-2 .

[Comparative Examples 1 to 3]

In Comparative Examples 1 to 3, a urethane pressure-sensitive adhesive was obtained in the same manner as in Example 1, except that the kind of the material used and the blending ratio were changed as shown in Tables 2-5 and 3-3.

[Comparative Example 4]

100 parts of the urethane prepolymer (A-2) obtained in Synthesis Example 2, 20 parts of "MONOCIZER-W-260" (polyalkylene glycol compound, product of DIC CORPORATION) as the hydrophilic additive, "IRGANOX L 135 0.3 part of ultraviolet absorber "TINUVIN 571" (product of BASF SE), 0.3 part of light stabilizer "TINUVIN 765" (product of BASF SE), 15 parts of isocyanate curing agent (I-1) And 100 parts of ethyl acetate as a solvent were mixed and stirred with a disper to obtain a urethane pressure-sensitive adhesive. Table 2-5 shows the types and blend ratios of the materials used.

[Comparative Example 5]

, 70 parts of a polyether polyol (a-1-9), 18 parts of a polyether polyol (a-1-4), 12 parts of a polyether polyol (a-1-10) (I-3) as a solvent, 0.006 part of a polyisocyanate compound (I-1) as a catalyst, 0.04 parts of "Nashematic iron" (product of NIHON KAGAKU SANGYO CO., LTD., Tris (acetylacetone) , And the mixture was stirred with a disper to obtain a urethane pressure-sensitive adhesive.

In Comparative Example 5, instead of the urethane prepolymer, three kinds of polyols were used as they were. Table 3-3 shows the types and mixing ratios of the materials used.

[Production and evaluation of first pressure-sensitive adhesive sheet for evaluation (release sheet / pressure-sensitive adhesive layer / base sheet)] [

In each of Examples 1 to 26 and Comparative Examples 1 to 5, a first pressure-sensitive adhesive sheet for evaluation (release sheet / adhesive layer / base sheet) was obtained as follows.

A polyethylene terephthalate (PET) sheet (Lumirror T-60, manufactured by TORAY INDUSTRIES, INC.) Having a thickness of 50 mu m was prepared as a base sheet. Comma Coater (registered trademark) was used to coat the surface of the substrate sheet with the obtained urethane pressure-sensitive adhesive at a coating speed of 30 m / min to a thickness of 80 탆 after drying. The formed coating layer was dried at 100 for 2 minutes to form an adhesive layer. The formed pressure-sensitive adhesive layer was evaluated for suitability for thick film coating.

Then, a release sheet (SPASTIC SP-PET38, manufactured by Lintec Corporation) having a thickness of 38 mu m was attached to the formed pressure-sensitive adhesive layer and cured for one week under the condition of 23 · 50% RH, Sensitive adhesive sheet (release sheet / pressure-sensitive adhesive layer / base sheet) was obtained. The first adhesive sheet for evaluation was evaluated for adhesion, wet heat-resistance whitening property, wetting property, and surface resistance value. In this specification, &quot; RH &quot; represents relative humidity.

[Production and evaluation of second pressure-sensitive adhesive sheet for evaluation (second release sheet / pressure-sensitive adhesive layer / first release sheet)

In each of Examples 1 to 26 and Comparative Examples 1 to 5, a second pressure-sensitive adhesive sheet for evaluation (release sheet / adhesive layer / base sheet) was obtained as follows.

A urethane adhesive obtained on a first peel sheet (Filmbyna 50 E0010-DG3, manufactured by FUJIMORI KOGYO CO., LTD.) Having a thickness of 50 탆 was coated with a Comma Coater (registered trademark) at a coating speed of 3 m / min , And the thickness after drying was 80 占 퐉. The formed coating layer was dried at 100 for 2 minutes to form an adhesive layer. A second release sheet (SPASTIC SP-PET38, manufactured by Lintec Corporation) having a thickness of 38 mu m was adhered onto the adhesive layer and cured for 30 minutes under the condition of 23 · 50% RH, (Second release sheet / adhesive layer / first release sheet). The gel fraction of the second pressure-sensitive adhesive sheet for evaluation was evaluated.

[Evaluation Items and Evaluation Methods]

(adhesiveness)

A test sample having a width of 25 mm and a length of 100 mm was cut from the first pressure-sensitive adhesive sheet for evaluation. The release sheet was peeled off from the measurement sample under the condition of 23 · 50% RH. The surface of the exposed adhesive layer was adhered to a stainless steel plate (SUS304), pressed with a 2 kg roll on the side of the base sheet, and allowed to stand for 24 hours. Thereafter, the adhesive strength of the adhesive layer was measured using a tensile tester in accordance with JIS Z 0237 at a peeling speed of 300 mm / min and a peeling angle of 180 °. The evaluation criteria are as follows.

Good: Less than 20 mN / 25 mm.

?: 20 to 100 mN / 25 mm, practically usable.

×: 100 mN / 25 mm sec, practically impossible.

(Anti-wet heat whitening)

A test sample having a width of 25 mm and a length of 100 mm was cut from the first pressure-sensitive adhesive sheet for evaluation. The release sheet was peeled off from the measurement sample under the condition of 23 · 50% RH, and the surface of the exposed adhesive layer was adhered to the glass plate and allowed to stand for 1 hour. This was allowed to stand under the condition of 60 · 90% RH for 72 hours and left under the condition of 23 · 50% RH for 1 hour. Thereafter, using a dumbbell system (haze meter) NDH5000W (manufactured by NIPPON DENSHOKU INDUSTRIES Co., Haze (biliary) was measured according to K7136. The evaluation criteria are as follows.

○: Haze less than 2%, good.

?: Less than 5% haze, practicable.

X: haze 5% or more, practically inapplicable.

(Wetting property)

A test sample having a width of 100 mm and a length of 200 mm was cut from the first pressure-sensitive adhesive sheet for evaluation. The measurement sample was allowed to stand under a condition of 23 · 50% RH for 30 minutes, and the release sheet was peeled from the measurement sample. Then, both ends of the adhesive sheet in the longitudinal direction were gripped by both hands, and the center of the exposed surface of the adhesive layer was brought into contact with the glass plate, and both hands were separated. The time until the entirety of the adhesive layer adhered to the glass plate was measured by the self-weight of the adhesive sheet, and the wetting property to the glass was evaluated. The shorter the time until bonding with the glass plate is, the better the affinity to the glass is. Therefore, it is easy to protect the glass member in the manufacturing process of various optical members using the glass member. The evaluation criteria are as follows.

○: Less than 3 seconds, good.

?: Less than 3 seconds and less than 5 seconds, practicable.

×: more than 5 seconds, practically impossible.

(Suitability for thick film coating)

In the production step of the first pressure-sensitive adhesive sheet for evaluation, the surface of the pressure-sensitive adhesive layer formed was visually observed on the basis of the following criteria in the step before the release sheet was bonded. The evaluation criteria are as follows.

Good: The surface is smooth.

△: Smoothness was observed on the surface, which is practically usable.

X: Drying force or distortion was observed on the surface, which is not practical.

(Gel fraction (thick film coatability))

The gel fraction was measured as an index of the suitability of the thick film coating. When the state of high fluidity before full curing is continued for a long time during curing in the adhesive layer, the surface smoothness may be lowered. When the adhesive layer obtained after the heat drying treatment has a high gel fraction in a relatively short time, it is suitable for thick film coating due to rapid curing.

A test sample having a width of 30 mm and a length of 100 mm was cut from the second pressure-sensitive adhesive sheet for evaluation. Then, the first release sheet was peeled off from the measurement sample, and the surface of the exposed adhesive layer was adhered to a 200 mesh wire netting. Further, after peeling off the second release sheet, the entire adhesive layer was encased in the above-described wire netting. The mass of this structure was measured to remove the mass of the wire mesh, and the initial mass of the adhesive layer was obtained. Next, this structure was immersed in a sealed container containing 250 g of ethyl acetate at 50 for 24 hours, and then taken out. After drying the structure at 100 for 30 minutes, the mass was again measured to remove the mass of the wire mesh, and the mass of the adhesive layer was obtained. The gel fraction was obtained by the following calculation.

(Gel fraction) (%) = (mass of adhesive layer after immersion drying) / (mass of adhesive layer before immersion) 占 100

The evaluation criteria are as follows.

Good: 60% by mass or more.

?: 40 mass% or more and less than 60 mass%, practically usable.

X: less than 40% by mass, practically useless.

(Surface resistance value)

The surface resistance value was measured as an index of dust adhesion. A test sample having a width of 100 mm and a length of 100 mm was cut from the first pressure-sensitive adhesive sheet for evaluation. Then, the measurement sample was allowed to stand under the condition of 23 · 50% RH for 30 minutes, and the release sheet was peeled from the measurement sample. The measurement terminal was brought into contact with the exposed surface of the adhesive layer using a resistivity meter Hiresta UX MCP-HT800 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and the surface resistance value (? /?) Was measured. The evaluation criteria are as follows.

Good: Less than 1.0 x 10 &lt; ¹¹ &gt; ohm / square, good (dust adhesion is effectively suppressed).

?: 1 x 10 ¹¹ ? /? Or more and 1.0 x 10 ¹² ? /?, Practically usable.

×: Not less than 1 × 10 ¹² Ω / □, practically impossible.

[Evaluation results]

The evaluation results of Examples 1 to 26 and Comparative Examples 1 to 5 are shown in Tables 2-1 to 2-5 and Tables 3-1 to 3-3.

In Examples 1 to 19,

(A-1) excluding a polyether polyol having at least one EO group in one molecule, at least one polyether polyol (a-2) having at least one EO group in one molecule, Urethane prepolymer (A) which is a reaction product with polyisocyanate (b)

A urethane adhesive containing a fatty acid ester (B) was prepared.

In Examples 20 to 22,

(A-1) excluding a polyether polyol having at least one EO group in one molecule, at least one polyether polyol (a-2) having at least one EO group in one molecule, A urethane prepolymer (A) containing a reaction product of the above polyisocyanate (b) and a urethane pressure-sensitive adhesive containing a? -Diketone compound (X) was prepared.

In Examples 23 to 26,

(A-1) excluding at least one polyether polyol having at least one EO group in one molecule, at least one polyether polyol (a-2) having at least one EO group in one molecule, Urethane prepolymer (A) which is a reaction product with polyisocyanate (b)

A urethane adhesive containing a? -diketone compound (X) and a fatty acid ester (B) was prepared.

All of the pressure-sensitive adhesive sheets obtained in Examples 1 to 26 had good or comparatively good results for all evaluation items of adhesive strength, anti-wet heat wettability, wetting property, thick film coatability, gel fraction, and surface resistance value.

The pressure-sensitive adhesive sheet obtained in Examples 20 to 26, in which a urethane pressure-sensitive adhesive containing urethane prepolymer (A) and a? -Diketone compound (X) was produced, exhibited remarkably reduced surface resistance values of the pressure- The resistance value was a level at which dust adhesion was effectively suppressed.

In each of Examples 1 to 26, the production and evaluation of the pressure-sensitive adhesive sheet were carried out in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was changed from 80 μm to 10 μm and 30 μm. Evaluation results were obtained.

In Comparative Examples 1 to 3,

(D), which is a reaction product of at least one polyol (a-1) excluding one polyether polyol having at least one EO group in one molecule and at least one polyisocyanate (b) A polyether polyol (a-2) having at least one EO group is not used)

A urethane adhesive containing a fatty acid ester (B) was produced.

All of the pressure-sensitive adhesive sheets obtained in Comparative Examples 1 to 3 had poor adhesiveness and curability of the pressure-sensitive adhesive layer, and the results were unsatisfactory with respect to the evaluation items of anti-wet heat and whiteness, thick coatability, gel fraction and surface resistance.

In Comparative Example 4,

(A-1) excluding a polyether polyol having at least one EO group in one molecule, at least one polyether polyol (a-2) having at least one EO group in one molecule, A urethane adhesive containing urethane prepolymer (A), which is a reaction product of polyisocyanate (b), but not containing any of? -Diketone compound (X) and fatty acid ester (B) was prepared.

In Comparative Example 4, a polyalkylene glycol compound as a hydrophilic additive was added to the urethane pressure-sensitive adhesive, but the effect of improving hydrophilicity was insufficient. This reason is not necessarily clear, but there is a possibility that the hydrophobic part of the additive is surface-oriented. Thus, the resultant pressure-sensitive adhesive sheet had poor results with respect to the evaluation items of anti-wet heat heating.

In addition, since the amount of the hydrophilic additive added is large, the curing property is not good even when the urethane prepolymer (A) as in Examples 1 to 26 is used, and the obtained pressure sensitive adhesive sheet has the following results for evaluation items of the thick film coatability and gel fraction It was bad.

In Comparative Example 5, a urethane pressure-sensitive adhesive containing no urethane prepolymer and three kinds of polyether polyols having no EO group and a? -Diketone compound (X) was produced.

The pressure-sensitive adhesive sheet obtained in Comparative Example 5 had poor hydrophilicity and curability of the pressure-sensitive adhesive layer, and the results were unsatisfactory with respect to the evaluation items of the adhesive strength, anti-wet heat resistance, thick film coatability and gel fraction. Further, even with the use of the? -Diketone compound (X), the pressure-sensitive adhesive sheet obtained in Comparative Example 5 in which the urethane prepolymer (A) having an EO group was not used had poor results with respect to the evaluation items of the surface resistance value.

[Table 1-1]

[Table 1-2]

[Table 1-3]

[Table 1-4]

[Table 1-5]

[Table 2-1]

[Table 2-2]

[Table 2-3]

[Table 2-4]

[Table 2-5]

[Table 3-1]

[Table 3-2]

[Table 3-3]

The present invention is not limited to the above-described embodiments and examples, and appropriate design changes are possible without departing from the spirit of the present invention.

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2015-183508, filed September 17, 2015, the entire disclosure of which is hereby incorporated by reference.

10, 20 adhesive sheet
11, 21 Base sheet
12, 22 A, 22 B adhesive layer
13, 23 A, 23 B Peeling sheet

Claims (10)

At least one polyol (a-1) excluding a polyether polyol having at least one ethyleneoxy group in a molecule, at least one polyether polyol (a-2) having at least one ethyleneoxy group in one molecule, A urethane prepolymer (A) which is a reaction product with at least one polyisocyanate (b);
Isocyanate curing agent (I); And
? -diketone compound (X); &Lt; / RTI &gt;
The method according to claim 1,
The amount of the at least one polyether polyol (a-2) is preferably 50 parts by mass or more per 100 parts by mass of the total of 100 parts by mass of the at least one polyol (a-1) and the at least one polyether polyol (a- Urethane pressure-sensitive adhesive of less than 100 parts by mass.
3. The method according to claim 1 or 2,
Wherein the at least one polyol (a-1) is at least one selected from the group consisting of a polyester polyol having no ethyleneoxy group, a polyether polyol having no ethyleneoxy group, a polycaprolactone polyol having no ethyleneoxy group, and a polycarbonate polyol having no ethyleneoxy group And at least one polyol selected from the group consisting of polyurethane,
At least one polyol (a-1) excluding a polyether polyol having at least one ethyleneoxy group in a molecule, at least one polyether polyol (a-2) having at least one ethyleneoxy group in one molecule, A urethane prepolymer (A) which is a reaction product with at least one polyisocyanate (b);
Isocyanate curing agent (I); And
A urethane adhesive comprising a fatty acid ester (B).
The method according to claim 1 or 4,
Wherein the urethane prepolymer (A) has a weight average molecular weight of 30,000 to 500,000.
The method according to claim 1 or 4,
Wherein the polyisocyanate (b) is an aliphatic polyisocyanate.
The method according to claim 1 or 4,
A urethane pressure-sensitive adhesive further comprising an antioxidant.
At least one polyol (a-1) excluding a polyether polyol having at least one ethyleneoxy group in a molecule, at least one polyether polyol (a-2) having at least one ethyleneoxy group in one molecule, A urethane prepolymer (A) obtained by reacting one or more polyisocyanates (b); And
wherein at least one compound selected from the group consisting of a? -diketone compound (X) and a fatty acid ester (B) is blended.
A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer comprising a cured product of the urethane pressure-sensitive adhesive according to any one of claims 1 to 4.
A display comprising a pressure-sensitive adhesive layer comprising a cured product of the urethane pressure-sensitive adhesive according to any one of claims 1 to 4.

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