CN114206459A

CN114206459A - Adhesive and adhesive sheet

Info

Publication number: CN114206459A
Application number: CN202180003780.3A
Authority: CN
Inventors: 戸根嘉孝; 坪井优季; 柏村岳; 宫沢豪; 斋藤秀平
Original assignee: Toyo Ink SC Holdings Co Ltd; Toyochem Co Ltd
Current assignee: Toyochem Co Ltd; Artience Co Ltd
Priority date: 2020-06-30
Filing date: 2021-06-01
Publication date: 2022-03-18
Also published as: JP2022011609A; TW202202540A; WO2022004243A1; KR20230026238A; JP6879414B1

Abstract

The invention provides an adhesive and an adhesive sheet using the same, wherein the adhesive has good initial hardening performance, can form an adhesive layer which inhibits the increase of adhesive force even under the condition of being exposed to a thermal environment, particularly a damp and hot environment and has good re-peeling performance. The adhesive of the present invention comprises: a hydroxyl-terminated Urethane Prepolymer (UPH) which is a reaction product of one or more active hydrogen group-containing compounds (H) having a plurality of active hydrogen groups in one molecule and one or more polyisocyanates (N); and a polyfunctional isocyanate compound (I), wherein the adhesive is a urethane adhesive having a branching degree of 0.2 to 0.8 as measured by GPC-MALS method in a hydroxyl-terminated Urethane Prepolymer (UPH).

Description

Adhesive and adhesive sheet

Technical Field

The present invention relates to an adhesive and an adhesive sheet.

Background

Conventionally, as surface protection sheets for various members, adhesive sheets having an adhesive layer formed on a base sheet have been widely used. Examples of the adhesive include acrylic adhesives, silicone adhesives, and urethane adhesives. Acrylic adhesives have excellent adhesive strength, but have high adhesive strength, and therefore have poor removability after being attached to an adherend. Regarding the silicone adhesive, there are also the following concerns: the silicone resin having a relatively low molecular weight is easily contaminated in an adherend, and is volatilized and adsorbed on the surface of a device such as an electronic component, which causes a problem. In contrast, the urethane adhesive has good adhesion to an adherend, is relatively excellent in removability, and is not easily volatilized.

In the present specification, unless otherwise specified, "adhesive" refers to an adhesive having removability (removable adhesive), and "adhesive sheet" refers to an adhesive having removability (removable adhesive sheet).

The following methods are known as a method for producing a urethane adhesive: a method of using a hydroxyl-terminated urethane prepolymer which is a reaction product of an active hydrogen group-containing compound such as a polyol and a polyisocyanate, and a polyfunctional isocyanate compound; and a method of reacting a polyol with a polyfunctional isocyanate compound in one shot (one shot method) without using a hydroxyl-terminated urethane prepolymer.

A general method for producing an adhesive sheet includes: a coating step of coating an adhesive on a base sheet; a heating step of forming an adhesive layer containing a cured product of an adhesive by heating and drying the formed coating layer; a winding step of winding the obtained adhesive sheet around a core to form an adhesive sheet roll; and a curing step of curing the adhesive sheet roller.

Flat panel displays such as Liquid Crystal Displays (LCDs) and organic electroluminescent displays (OELDs), and touch panel displays in which the flat panel displays and a touch panel are combined are widely used in electronic devices such as Televisions (TVs), Personal Computers (PCs), mobile phones, and portable information terminals.

The urethane adhesive sheet can be preferably used as a surface protective sheet for flat panel displays, touch panel displays, and substrates produced or used in the production steps of these (glass substrates, ITO/glass substrates having an Indium Tin Oxide (ITO) film formed on a glass substrate, and the like), optical members, and the like.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. Hei 11-256124

Patent document 2: international publication No. 2015/141380

Patent document 3: japanese patent laid-open publication No. 2017-193601

Patent document 4: international publication No. 2015/141379

Disclosure of Invention

Problems to be solved by the invention

The urethane adhesive is cured immediately after the production. If the initial curing property of the urethane adhesive is too low, the releasability of the adhesive layer is reduced, and the components of the adhesive layer are likely to adhere to fingers, an adherend, and the like in contact with the adhesive layer. In such a case, after the pressure-sensitive adhesive sheet is peeled off from the fingers, the adherend, and the like, so-called "adhesive residue" (also referred to as "adherend contamination") is likely to occur in which the components of the pressure-sensitive adhesive layer remain on the fingers, the adherend, and the like. The urethane adhesive preferably has good initial curability.

When the adhesive sheet is exposed to a hot environment, particularly a moist heat environment, the anchoring strength between the adherend and the adhesive layer increases, and as a result, the adhesive force of the adhesive layer tends to increase, and the removability tends to decrease. The pressure-sensitive adhesive sheet preferably has good removability even when exposed to a hot environment, particularly a moist heat environment, and is contaminated with an adherend in which no adhesive layer component remains on the surface of the adherend after removability.

Related techniques of the present invention include patent documents 1 to 4.

Patent document 1 discloses a water-dispersible pressure-sensitive adhesive (acrylic pressure-sensitive adhesive) for repeeling, which comprises an aqueous dispersion of a polymer of a monomer containing an alkyl (meth) acrylate ester having 4 to 12 carbon atoms in the alkyl group as a main component, wherein the polymer has a weight average molecular weight of 250 ten thousand or more and the number of branches per molecule of a polymer having a molecular weight of 500 ten thousand or less (first invention).

Patent document 2 discloses an adhesive composition (acrylic adhesive) for a polarizing plate, which contains:

(A) a (meth) acrylic copolymer obtained by copolymerizing monomer components including an alkyl (meth) acrylate having an alkyl group and 4 to 18 carbon atoms and a carboxyl group-containing monomer, and having a branching degree of 0.55 or less and an acid value of 0.1 to 7.8mgKOH/g, as measured by gel permeation chromatography/multi-angle laser light scattering (GPC-MALS);

(B1) an isocyanate compound; and

(B2) a metal chelate compound (first invention).

Patent document 3 discloses a photocurable adhesive precursor composition containing an ethylenically unsaturated monomer, a prepolymer having a monomer unit derived from a hydrogen-donating monomer, and a hydrogen-abstracting photoinitiator (first invention).

The ethylenically unsaturated monomer is preferably (meth) acrylate (paragraph 0021).

The hydrogen-donating monomer preferably has an ethylenically unsaturated double bond and at least one selected from the group consisting of an amino group, an amide group, a hydroxyl group, a thiol group, a heterocycle, and an alkylene oxide chain (second invention).

Patent document 3 discloses a photocurable adhesive containing a randomly branched (co) polymer having a branching degree of 0.25 to 0.44 (fifth invention).

An acrylic pressure-sensitive adhesive was produced in examples 1 to 3 of patent document 3.

Patent document 4 discloses an adhesive composition (acrylic adhesive) for a polarizing plate, which contains: (A) a (meth) acrylic copolymer obtained by copolymerizing monomer components including an alkyl (meth) acrylate having an alkyl group with 4 to 18 carbon atoms and a hydroxyl group-containing monomer, and having a branching degree of 0.55 or less as measured by gel permeation chromatography/multi-angle laser light scattering detector (GPC-MALS); and (B) an isocyanate compound (first invention).

The symbols of the components described in patent documents 1 to 4 are those described in these documents, and are unrelated to the symbols used for the components of the present invention.

Patent documents 1 to 4 describe the branching number or branching degree of an acrylic (co) polymer. These patent documents all relate to acrylic adhesives, not to urethane adhesives. There is no document describing the branching degree of a prepolymer or a raw material thereof in a urethane adhesive.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive agent which has good initial curability, can form an adhesive layer which suppresses an increase in adhesive force even when exposed to a thermal environment, particularly a moist thermal environment, and has good removability, and an adhesive sheet using the adhesive agent.

Means for solving the problems

The adhesive of the present invention comprises:

a hydroxyl-terminated Urethane Prepolymer (UPH) which is a reaction product of one or more active hydrogen group-containing compounds (H) having a plurality of active hydrogen groups in one molecule and one or more polyisocyanates (N); and

a polyfunctional isocyanate compound (I),

the adhesive is a urethane adhesive having a branching degree of 0.2 to 0.8 as measured by GPC-MALS method in a hydroxyl-terminated Urethane Prepolymer (UPH).

In the adhesive of the first embodiment of the present invention,

the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HX) having a branching degree of 0.5 or less as measured by GPC-MALS method,

the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree of 0.2 to 0.6 as measured by GPC-MALS method.

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

the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HY) having a branching degree of more than 0.5 as measured by GPC-MALS method,

the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree of more than 0.6 and 0.8 or less as measured by GPC-MALS method.

The adhesive sheet of the present invention includes a substrate sheet and an adhesive layer containing a cured product of the adhesive of the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided an adhesive which has good initial curability, can form an adhesive layer which suppresses an increase in adhesive force even when exposed to a thermal environment, particularly a moist thermal environment, and has good removability, and an adhesive sheet using the adhesive.

According to the first embodiment of the present invention, an adhesive which has excellent initial curability and removability (an effect of suppressing an increase in adhesive force) when exposed to a thermal environment, particularly a moist thermal environment, and which can form an adhesive layer having excellent substrate adhesiveness, scratch resistance, and curved surface adhesiveness, and an adhesive sheet using the adhesive can be provided.

According to the second embodiment of the present invention, there can be provided an adhesive which is excellent in initial curability and removability (effect of suppressing increase in adhesive force) when exposed to a thermal environment, particularly a moist thermal environment, and which can form an adhesive layer excellent in folding resistance, cuttability, and heat resistance, and an adhesive sheet using the adhesive.

Drawings

Fig. 1 is a schematic cross-sectional view of an adhesive sheet according to a first embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of an adhesive sheet according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram of an example of production of a prepolymer.

Detailed Description

[ Adhesives ]

The adhesive of the present invention comprises:

a hydroxyl-terminated Urethane Prepolymer (UPH) (also simply referred to as "prepolymer") which is a reaction product of one or more active hydrogen group-containing compounds (H) having a plurality of active hydrogen groups in one molecule and one or more polyisocyanates (N); and

a polyfunctional isocyanate compound (I),

the adhesive is a re-peelable urethane adhesive having a degree of branching α (also simply referred to as "degree of branching α") of 0.2 to 0.8 as measured by GPC-MALS method in a hydroxyl-terminated Urethane Prepolymer (UPH).

The adhesive sheet of the present invention is a urethane adhesive sheet comprising a substrate sheet and an adhesive layer containing a cured product of the adhesive of the present invention.

The "degree of branching α" is measured by a known method using a device (also referred to as "GPC-MALS" or "GPC-MALS-VISCO") in which a multi-angle light scattering detector (MALS) is combined with a viscosity detector (VISCO) and a Gel Permeation Chromatograph (GPC). For the measurement of the branching degree α by GPC-MALS, refer to patent documents 1 to 4 listed in [ background art ].

The GPC method is a method in which a solution of a sample whose molecular weight is to be measured is passed through a column filled with a porous material such as silica, and the molecular weight is measured from the elution time. The sample having a smaller molecular size passes through a deeper portion in the pores of the porous material, and thus the dissolution time becomes longer. The molecular weight of the sample is determined by comparing the dissolution time with a standard of known molecular weight.

The length of the elution time of the sample in the GPC method corresponds to the size of the molecular size, but the size of the molecular size and the size of the molecular weight are not strictly related. Since the molecular size varies depending on the affinity with the eluent, the molecular weight cannot be accurately measured depending on the polarity of the sample. The molecular size also differs depending on the branching state of the molecule. The more branches, the smaller the molecular size, even if the molecular weight is the same. Even in the case of samples having the same elution time, the actual molecular weight (absolute molecular weight) may differ depending on the polarity or branching state of the molecule, but in the GPC method, the measured molecular weight is the same in the samples having the same elution time.

In GPC-MALS, in addition to general GPC measurement, a sample solution is irradiated with laser light of a specific wavelength to measure the intensity of scattered light caused by rayleigh scattering. The scattered light intensity varies depending on the molecular size and branching state. For example, in the case of a sample having a small molecular size and no branching, the scattering point is one, and the intensity of scattered light is low. In the case of a sample having a large molecular size and many branches, the number of scattering points increases, and the intensity of scattered light increases. In GPC-MALS, the intrinsic viscosity of the sample was also measured by VISCO. The absolute molecular weight can also be determined by GPC-MALS.

The relationship among intrinsic viscosity, density, weight average molecular weight (Mw) and degree of branching α is represented by the formula (below) calculated in Mark-Houwink-Sakurad.

[ number 1]

log[η]＝logK+αlogMw

Wherein log [ η ] represents the intrinsic viscosity, logK represents the density, Mw represents the weight-average molecular weight, and α represents the degree of branching. In the (pre) polymer molecule, the smaller the α value, the more branched (high branched) and the spherical or nearly spherical shape (range of approximately α < 0.5), and the larger the α value, the less branched (low branched) and the rod-like or nearly rod-like shape (range of approximately α > 0.8).

For example, as shown in fig. 3, when 3 molecules of a relatively high branched polyol (PO1), 5 molecules of a relatively low branched polyol (PO2), and 7 molecules of a relatively low branched polyisocyanate (P11) are reacted, a relatively high branched prepolymer (PP1), a relatively low branched prepolymer (PP2), or a prepolymer in a branched state in the middle of these may be produced. The prepolymer (PP1) and the prepolymer (PP2) have the same molecular weight, but different branching states, molecular sizes and molecular morphologies. FIG. 3 is a schematic diagram of a reaction example.

As described in the section of [ problem to be solved by the invention ], there has been no document describing the branching degree α of a prepolymer or a raw material thereof in a urethane adhesive.

In the present invention, the branching degree α of the prepolymer or the raw material thereof is optimized, and the properties of the adhesive are optimized.

The degree of branching α of the prepolymer can be adjusted depending on the degree of branching α of each of the plural raw materials used, the combination of the plural raw materials used, the amount ratio of the plural raw materials used, the reaction conditions, the reaction procedure, and the like.

The degree of branching alpha of a hydroxyl-terminated Urethane Prepolymer (UPH) contained in the adhesive of the present invention is 0.2 to 0.8.

When the degree of branching α is less than 0.2, the prepolymer molecules are highly branched (highly branched) and have a spherical or nearly spherical shape. In the adhesive containing a highly branched hydroxyl-terminated Urethane Prepolymer (UPH), when the hydroxyl-terminated Urethane Prepolymer (UPH) is reacted with a curing agent, an intramolecular reaction excessively proceeds to suppress the progress of an intermolecular crosslinking reaction, and thus the initial curing property is easily lowered. Further, since the repeelability of the adhesive layer is reduced around a portion having a low degree of intermolecular crosslinking, so-called "adhesive residue" (also referred to as "adherend contamination") is likely to occur in which a component of the adhesive layer remains on a finger, an adherend, and the like after the adhesive sheet is peeled from the finger, the adherend, and the like. In addition, when exposed to a thermal environment, particularly a moist thermal environment, the increase in adhesive force becomes large, and removability is easily lowered.

When the degree of branching α exceeds 0.8, the prepolymer has few branches (low branches) and has a rod-like or rod-like shape. In the adhesive containing a low-branched hydroxyl-terminated Urethane Prepolymer (UPH), since the hydroxyl-terminated Urethane Prepolymer (UPH) is rod-like or nearly rod-like in shape, it is difficult to form a crosslinked structure with high density, and initial curability is easily lowered. Further, the crosslinked structure becomes insufficient, and as a result, the re-peelability of the adhesive layer is lowered, and after the adhesive sheet is peeled from the fingers, the adherend, and the like, so-called "adhesive residue" (adherend contamination) in which the components of the adhesive layer remain on the fingers, the adherend, and the like is likely to occur. In addition, when exposed to a thermal environment, particularly a moist thermal environment, the increase in adhesive force becomes large, and removability is easily lowered.

By using a hydroxyl-terminated Urethane Prepolymer (UPH) having a branching degree alpha within the range of 0.2 to 0.8, when the hydroxyl-terminated Urethane Prepolymer (UPH) is reacted with a curing agent, an intramolecular reaction and an intermolecular crosslinking reaction proceed moderately, and a high-density crosslinked structure is formed at an early stage, so that an adhesive having good initial curing properties, which can form an adhesive layer having good removability while suppressing an increase in adhesive force even when exposed to a thermal environment, particularly a moist-heat environment, can be provided.

(first embodiment)

In the adhesive of the first embodiment of the present invention, the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less as measured by GPC-MALS method, and the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree α of 0.2 to 0.6 as measured by GPC-MALS method.

In the adhesive of the first embodiment, since the intramolecular cross-linking reaction proceeds early and predominantly while the progress of the intermolecular cross-linking reaction is maintained, the initial curability and the removability (effect of suppressing the increase in adhesive force) when exposed to a thermal environment, particularly a moist thermal environment are excellent, and further the dense structure formed by the intramolecular cross-linking and the sparse structure formed by the intermolecular cross-linking can be simultaneously satisfied, and therefore, an adhesive layer having excellent substrate adhesiveness, scratch resistance, and curved surface adhesiveness can be formed.

In the adhesive of the first embodiment, in order to effectively obtain the above-mentioned action and effect, the degree of branching α of the hydroxyl-terminated Urethane Prepolymer (UPH) measured by GPC-MALS method is preferably 0.3 to 0.6, and more preferably 0.4 to 0.6.

In the pressure-sensitive adhesive of the first embodiment, the one or more active hydrogen group-containing compounds (H) are preferably an active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less as measured by GPC-MALS method, which is contained in an amount of 50% by mass or more and less than 100% by mass, and an active hydrogen group-containing compound (HY) having a branching degree α of more than 0.5 as measured by GPC-MALS method, which is contained in an amount of more than 0% by mass and less than 50% by mass, in order to effectively obtain the above-described action and effect.

When the active hydrogen group-containing compound (H) satisfies the above-mentioned regulation, the produced urethane bond has a stronger contrast between a sparse part and a dense part, and therefore the above-mentioned action and effect by the expression of the sea-island structure are effectively enhanced.

In the adhesive of the first embodiment, the one or more active hydrogen group-containing compounds (H) preferably contain an active hydrogen group-containing compound (HX-S) having a branching degree α of 0.3 or less as measured by GPC-MALS method, and more preferably contain an active hydrogen group-containing compound having a branching degree α of 0.2 or less, from the viewpoint of effectively obtaining the above-described action and effect.

The adhesive of the first embodiment more preferably contains 70% by mass or more of one or more active hydrogen group-containing compounds (HX) having a branching degree α of 0.5 or less. The adhesive of the first embodiment more preferably contains more than 0% by mass and less than 30% by mass of one or more active hydrogen group-containing compounds (HY) having a branching degree α of more than 0.5, and particularly preferably contains more than 10% by mass and less than 30% by mass.

When the active hydrogen group-containing compound (H) satisfies the above-mentioned requirements, a more dense urethane bond is formed, and the above-mentioned action and effect due to the expression of the sea-island structure are effectively enhanced.

(second embodiment)

In the adhesive of the second embodiment of the present invention, the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HY) having a branching degree α of more than 0.5 as measured by GPC-MALS method, and the branching degree α of the hydroxyl-terminated Urethane Prepolymer (UPH) as measured by GPC-MALS method is more than 0.6 and 0.8 or less.

In the adhesive of the second embodiment, since the crosslinked structure is formed at an early stage by the moderate branched structure contained in the hydroxyl-terminated Urethane Prepolymer (UPH), an adhesive layer having excellent initial curability and removability (effect of suppressing increase in adhesive force) when exposed to a thermal environment, particularly, a moist thermal environment can be formed. In addition, since the adhesive of the second embodiment has a structure with a relatively low crosslinking density, an adhesive layer having excellent folding endurance, cuttability, and heat resistance can be formed.

In the adhesive of the second embodiment, the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree α of 0.7 to 0.8 as measured by GPC-MALS method, in order to form a uniform and moderate crosslinked structure and to effectively obtain the above-mentioned effects.

In the adhesive of the second embodiment, in order to form a uniform and moderate crosslinked structure and to effectively obtain the above-described action and effect, the one or more active hydrogen group-containing compounds (H) preferably contain 50% by mass or more and less than 100% by mass of an active hydrogen group-containing compound (HY) having a branching degree α of more than 0.5 as measured by GPC-MALS method, and contain more than 0% by mass and less than 50% by mass of an active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less as measured by GPC-MALS method.

In the adhesive of the second embodiment, the one or more active hydrogen group-containing compounds (H) preferably contain 50 mass% or more of an active hydrogen group-containing compound (HY-L) having a branching degree α of more than 0.6 as measured by GPC-MALS method, in order to form a uniform and moderate crosslinked structure and to effectively obtain the above-described action and effect.

In the adhesive of the second embodiment, the branching degree α of the active hydrogen group-containing compound (HY) is more preferably 0.8 or more.

The adhesive of the second embodiment more preferably contains 70% by mass or more of one or more active hydrogen group-containing compounds (HY). The adhesive of the second embodiment more preferably contains more than 0% by mass and less than 30% by mass of one or more active hydrogen group-containing compounds (HX) having a branching degree α of 0.5 or less, and particularly preferably contains 10% by mass or more and less than 30% by mass.

(hydroxyl-terminated Urethane Prepolymer (UPH))

The hydroxyl-terminated Urethane Prepolymer (UPH) is a reaction product obtained by copolymerizing one or more active hydrogen group-containing compounds (H) with one or more polyisocyanates (N). The copolymerization reaction may be carried out in the presence of one or more catalysts as required. If necessary, one or more solvents may be used in the copolymerization reaction.

In the present invention, the degree of branching α of each of the plurality of raw materials used, the combination of the plurality of raw materials used, the amount ratio of the plurality of raw materials used, the reaction conditions, the reaction procedure, and the like are adjusted so that the degree of branching α of the hydroxyl-terminated Urethane Prepolymer (UPH) is in the range of 0.2 to 0.8.

In the adhesive of the first embodiment, the weight average molecular weight (Mw) of the hydroxyl-terminated Urethane Prepolymer (UPH) is preferably 4 ten thousand or more, more preferably 6 ten thousand or more, and particularly preferably 8 ten thousand or more. When Mw is not less than the lower limit, initial hardenability and removability are improved.

In the adhesive of the second embodiment, the weight average molecular weight (Mw) of the hydroxyl-terminated Urethane Prepolymer (UPH) is preferably 1 ten thousand or more, more preferably 2 ten thousand or more, and particularly preferably 3 ten thousand or more. When Mw is not less than the lower limit, initial hardenability, removability, and heat resistance are improved.

< Compound (H) containing active Hydrogen group >

The active hydrogen group-containing compound (H) is a compound having a plurality of active hydrogen groups in one molecule.

As the active hydrogen group, there can be mentioned: a hydroxyl group (hydroxyl group), a mercapto group, and an amino group (in the present specification, an amino group includes an imino group unless otherwise specified). As the active hydrogen group-containing compound (H), there can be mentioned: polyols having a plurality of hydroxyl groups in one molecule, polyamines having a plurality of amino groups in one molecule, aminoalcohols having an amino group and a hydroxyl group in one molecule, polythiols having a plurality of mercapto groups in one molecule, and the like. These active hydrogen group-containing compounds (H) may be non-polymeric or polymeric. These may be used singly or in combination.

Among them, polyhydric alcohols are preferable. Since polyamines and polythiols have high reactivity with polyisocyanates and a short pot life, when these are used, they are preferably used in combination with polyols.

As the polyol usable as the active hydrogen group-containing compound (H), there can be exemplified: polyester polyols, polyether polyols, polyacrylic polyols, polycaprolactone polyols, polycarbonate polyols, castor oil polyols, and the like. Among them, polyester polyols, polyether polyols, and combinations thereof are preferable in terms of having appropriate flexibility, adhesion of the adhesive layer, folding resistance, and curved surface adhesiveness. Further, the one or more active hydrogen group-containing compounds (H) are particularly preferably polyether polyols in terms of having a high hydrolysis resistance.

As the polyester polyol usable as the active hydrogen group-containing compound (H), known polyester polyols can be used. Examples of the polyester polyol include compounds (esterified products) obtained by esterification of one or more polyol components and one or more acid components.

As the polyol component of the raw material, there can be mentioned: ethylene Glycol (EG), Propylene Glycol (PG), diethylene glycol, 1, 3-butanediol, 1, 4-butanediol, neopentyl glycol, 3-methyl-1, 5-pentanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2, 4-diethyl-1, 5-pentanediol, 1, 2-hexanediol, 1, 6-hexanediol, 2-ethyl-1, 3-hexanediol, 1, 8-octanediol, 1, 9-nonanediol, 2-methyl-1, 8-octanediol, 1, 8-decanediol, octadecanediol, glycerol, trimethylolpropane, pentaerythritol, and the like.

As the acid component of the raw material, there can be mentioned: succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1, 12-dodecanedioic acid, 1, 14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1, 4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 1, 4-naphthalenedicarboxylic acid, 4' -biphenyldicarboxylic acid, acid anhydrides thereof, and the like.

As the polyether polyol usable as the active hydrogen group-containing compound (H), known polyether polyols can be used. The polyether polyol includes a compound (addition polymer) obtained by addition polymerization of one or more types of oxirane compounds using an active hydrogen group-containing compound having a plurality of active hydrogen groups in one molecule as an initiator.

Examples of the initiator include hydroxyl group-containing compounds and amines. Specifically, there may be mentioned: difunctional initiators such as Ethylene Glycol (EG), Propylene Glycol (PG), 1, 4-butanediol, neopentyl glycol, butylethylpentanediol, N-aminoethylethanolamine, isophoronediamine, and xylylenediamine; trifunctional initiators such as glycerin, trimethylolpropane and triethanolamine; and tetrafunctional initiators such as pentaerythritol, ethylenediamine, and aromatic diamines.

Examples of the oxirane compound include: alkylene Oxide (AO) such as Ethylene Oxide (EO), Propylene Oxide (PO), and Butylene Oxide (BO); tetrahydrofuran (THF), and the like.

The polyether polyol is preferably an alkylene oxide adduct of an active hydrogen group-containing compound (also referred to as polyoxyalkylene-based polyol). Among them, bifunctional polyether polyols such as polyethylene glycol (PEG), polypropylene glycol (PPG), PPG (PPG-EO) having Ethylene Oxide (EO) added to the end thereof, and polyalkylene glycol such as polytetramethylene glycol are preferable; and trifunctional polyether polyols such as alkylene oxide adducts of glycerin.

As polyamines usable as the active hydrogen group-containing compound (H), there can be exemplified: ethylenediamine, 1, 2-propylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, 1, 5-pentylenediamine, 1, 6-hexylenediamine, 1, 7-heptylenediamine, 1, 8-octylenediamine, 1, 9-nonylenediamine, 1, 10-decyldiamine, 1, 12-dodecyldiamine, 1, 14-tetradecylenediamine, 1, 16-hexadecyldiamine, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, methyliminobispropylamine, 1, 5-diamino-2-methylpentane, isophoronediamine, 1, 3-bisaminomethylcyclohexane, 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3, 3, 5-trimethyl-cyclohexylamine, 1, 4-butylenediamine, 1, 5-tetramethylenediamine, 1, 6-dodecyldiamine, 1, 14-tetradecylenediamine, 1, 16-hexadecyldiamine, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, 1, 5-trimethyl-cyclohexylamine, 3-aminopropane, 3-aminomethyl-cyclohexylamine, 2-diamine, and mixtures thereof, Aliphatic polyamines such as dimethylene diamine (MXDA), hexamethylene diamine carbamate, diethylene triamine, triethylene tetramine, tetraethyl pentamine, and pentaethylene hexamine of norbornane skeleton; aromatic polyamines such as 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane (MOCA), 4 '-diaminodiphenylmethane, 2, 4' -diaminodiphenylmethane, 3 '-diaminodiphenylmethane, 3, 4' -diaminodiphenylmethane, 2 '-diaminobiphenyl, 3' -diaminobiphenyl, 2, 4-diaminophenol, 2, 5-diaminophenol, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2, 3-tolylenediamine, 2, 4-tolylenediamine, 2, 5-tolylenediamine, 2, 6-tolylenediamine, 3, 4-tolylenediamine, and diethyltolylenediamine.

As the amino alcohol usable as the active hydrogen group-containing compound (H), there can be mentioned: monoamines having a hydroxyl group such as monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tris (hydroxymethyl) aminomethane, and 2-amino-2-ethyl-1, 3-propanediol; diamines having a hydroxyl group such as N- (2-hydroxypropyl) ethanolamine, and the like.

As polythiols usable as the active hydrogen group-containing compound (H), there can be exemplified: methanedithiol, 1, 3-butanedithiol, 1, 4-butanedithiol, 2, 3-butanedithiol, 1, 2-benzenedithiol, 1, 3-benzenedithiol, 1, 4-benzenedithiol, 1, 10-decanedithiol, 1, 2-ethanedithiol, 1, 6-hexanedithiol, 1, 9-nonanedithiol, 1, 8-octanedithiol, 1, 5-pentanedithiol, 1, 2-propanedithiol, 1, 3-propanedithiol, toluene-3, 4-dithiol, 3, 6-dichloro-1, 2-benzenedithiol, 1, 5-naphthalenedithiol, 1, 2-benzenedimethanethiol, 1, 3-benzenedimethanethiol, 1, 4-benzenedimethanethiol, 1, 3-benzenedithiol, 1, 4-benzenedimethanethiol, 1, 2-benzenedithiol, 1, 2-benzenedimethanethiol, 1, 2, 1, 2, 1, and benzene dimethanethiol, 4, 4' -thiobisbenzenethiol, 2, 5-dimercapto-1, 3, 4-thiadiazole, 1, 8-dimercapto-3, 6-dioxaoctane, 1, 5-dimercapto-3-thiapentane, 2-di-n-butylamino-4, 6-dimercapto-s-triazine, and thiol group-terminated polymers (polythioether polymers and the like).

The one or more active hydrogen group-containing compounds (H) may contain a difunctional active hydrogen group-containing compound and/or a trifunctional or more active hydrogen group-containing compound. In general, the bifunctional active hydrogen group-containing compound has two-dimensional crosslinkability and can impart appropriate flexibility to the adhesive layer. The trifunctional or higher active hydrogen group-containing compound has three-dimensional crosslinkability and can impart an appropriate hardness to the adhesive layer. By selecting the number of functional groups (the number of active hydrogen groups) of each active hydrogen group-containing compound (H), the properties of the urethane adhesive, such as adhesive force, cohesive force, and removability, can be adjusted. The number of functional groups of each material can be selected according to the application, etc., so that the properties such as adhesive force, cohesive force, and removability are in a preferable range.

The one or more active hydrogen group-containing compounds (H) are preferably a bifunctional active hydrogen group-containing compound and a trifunctional or more active hydrogen group-containing compound, from the viewpoint of facilitating both the adhesion and removability.

The active hydrogen group-containing compound (H) preferably contains an active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less as measured by GPC-MALS and an active hydrogen group-containing compound (HY) having a branching degree α of more than 0.5 as measured by GPC-MALS.

The branching degree α of the active hydrogen group-containing compound (H) can be adjusted depending on the structures of the plural raw materials used, the amount ratio of the plural raw materials used, the combination of the plural raw materials used, the reaction conditions, the reaction procedure, and the like.

Even if the raw material composition is the same, when the molecular weight of the active hydrogen group-containing compound (H) is changed, the branching degree α is also changed. Even if the molecular weight of the active hydrogen group-containing compound (H) is the same, the branching degree α changes if the branching structure changes. When the branch structure of the active hydrogen group-containing compound (H) is changed, the number of functional groups may be changed depending on the composition.

The number of functional groups of the active hydrogen group-containing compound (H) is not particularly limited. The number of functional groups of the active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less is preferably three or more in terms of easy availability of a highly branched structure. The number of functional groups of the active hydrogen group-containing compound (HY) having a branching degree α of more than 0.5 is preferably two or less in terms of easy availability of a low branching structure.

The number average molecular weight (Mn) of the active hydrogen group-containing compound (H) is not particularly limited. The Mn of the active hydrogen group-containing compound (H) is preferably 50 to 20000, more preferably 100 to 15000, and particularly preferably 400 to 10000, from the viewpoint of preferable adhesion and wettability of the adhesive layer.

The Mn of the active hydrogen group-containing compound (H) exerts an influence on the branching degree α. As described above, the branching degree α is also affected by factors other than Mn.

The active hydrogen group-containing compound (H) is preferably an active hydrogen group-containing compound having a primary hydroxyl group. In this case, the initial hardenability of the adhesive can be improved.

< polyisocyanate (N) >

As the polyisocyanate (N), known polyisocyanates (N) can be used, and there can be mentioned: aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate.

Examples of the aromatic polyisocyanate include: 1, 3-phenylene diisocyanate, 4 '-diphenyl diisocyanate, 1, 4-phenylene diisocyanate, 4' -diphenylmethane diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4 '-toluidine diisocyanate, 2, 4, 6-triisocyanate toluene, 1, 3, 5-triisocyanate benzene, dianisidine diisocyanate, 4' -diphenyl ether diisocyanate, and 4, 4 ', 4 "-triphenylmethane triisocyanate, omega' -diisocyanate-1, 3-dimethylbenzene, omega '-diisocyanate-1, 4-dimethylbenzene, omega' -diisocyanate-1, 4-diethylbenzene, 1, 4-tetramethylxylylene diisocyanate, and 1, 3-tetramethylxylylene diisocyanate.

Examples of the aliphatic polyisocyanate include: trimethylene diisocyanate, tetramethylene diisocyanate, Hexamethylene Diisocyanate (HDI), pentamethylene diisocyanate, 1, 2-propylene diisocyanate, 2, 3-butylene diisocyanate, 1, 3-butylene diisocyanate, dodecamethylene diisocyanate, and 2, 4, 4-trimethylhexamethylene diisocyanate, and the like.

Examples of the alicyclic polyisocyanate include: isophorone diisocyanate (IPDI), 1, 3-cyclopentane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, methyl-2, 6-cyclohexane diisocyanate, 4' -methylenebis (cyclohexyl isocyanate), and 1, 4-bis (isocyanotomethyl) cyclohexane, and the like.

Further, as the polyisocyanate, there can be mentioned: trimethylolpropane adduct, biuret (biuret) form, allophanate (allophanate) form, and trimer (the trimer including an isocyanurate ring) of the polyisocyanate.

Preferred raw material formulations of the hydroxyl-terminated Urethane Prepolymer (UPH) are as follows.

The raw material compounding ratio is preferably determined so that the ratio (NCO/H ratio) of the number of moles of the isocyanate group (NCO) in the polyisocyanate (N) to the total number of moles of the active hydrogen groups (H) in the plurality of active hydrogen group-containing compounds (H) is 0.20 to 0.95, preferably 0.40 to 0.85. The following tendency is exhibited: the closer the NCO/H ratio is to 1, the more likely it is to gel during synthesis of a hydroxyl-terminated Urethane Prepolymer (UPH). If the NCO/H ratio is 0.95 or less, gelation at the time of synthesizing the hydroxyl-terminated Urethane Prepolymer (UPH) can be effectively suppressed.

< catalyst >

If desired, more than one catalyst may be used in the polymerization of the hydroxyl-terminated Urethane Prepolymer (UPH). As the catalyst, known catalysts can be used, and examples thereof include tertiary amine compounds, organometallic compounds, and the like.

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

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

Examples of the tin-based compound include: dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate (dibutyl tin dimaleate), dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dioctyltin dilaurate, dibutyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide (triethyl tin ethoxide), tributyltin ethoxide (tributyl tin ethoxide), dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate, and the like.

Examples of the non-tin compound include: titanium systems such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead-based materials such as lead oleate, lead 2-ethylhexoate, lead benzoate, and lead naphthenate; iron series such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt systems such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc systems such as zinc naphthenate and zinc 2-ethylhexanoate; zirconium-based compounds such as zirconium naphthenate.

The kind and amount of the catalyst to be added can be suitably designed within a range in which the reaction proceeds well.

When a plurality of active hydrogen group-containing compounds (H) having different reactivities are used in combination, there is a possibility that a polymerization stability failure or clouding of the reaction solution may occur in a single catalyst system due to the difference in reactivity between these compounds. In such a case, by using two or more catalysts, it is easy to control the reaction (for example, reaction rate) and thus the problem can be solved. In the system using a plurality of active hydrogen group-containing compounds (H) having different reactivities in combination, it is preferable to use two or more catalysts. The combination of two or more catalysts is not particularly limited, and examples thereof include: tertiary amine/organic metal system, tin system/non-tin system, and tin system/tin system, etc. Tin-based/tin-based is preferred, and dioctyltin dilaurate and tin 2-ethylhexanoate are more preferred.

The mass ratio of tin 2-ethylhexanoate to dioctyltin dilaurate (tin 2-ethylhexanoate/dioctyltin dilaurate) is not particularly limited, but is preferably more than 0 and less than 1, and more preferably 0.2 to 0.8. If the mass ratio is less than 1, the balance of the catalyst activity is good, gelation and clouding of the reaction solution are effectively suppressed, and the polymerization stability is further improved.

The amount of the one or more catalysts used is not particularly limited, but is preferably 0.01 to 1.0% by mass based on the total amount of the one or more active hydrogen group-containing compounds (H) and the one or more polyisocyanates (N).

< solvent >

If necessary, one or more solvents may be used for the polymerization of the hydroxyl-terminated Urethane Prepolymer (UPH). As the solvent, known solvents can be used, and there can be mentioned: methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, and the like. In terms of solubility of the hydroxyl-terminated Urethane Prepolymer (UPH), boiling point of the solvent, and the like, ethyl acetate, toluene, and the like are particularly preferable.

< method for polymerizing hydroxyl-terminated Urethane Prepolymer (UPH) >

The polymerization method of the hydroxyl-terminated Urethane Prepolymer (UPH) is not particularly limited, and known polymerization methods such as bulk polymerization and solution polymerization can be used.

As the polymerization procedure of the hydroxyl-terminated Urethane Prepolymer (UPH), there can be mentioned:

procedure 1) procedure of charging one or more active hydrogen group-containing compounds (H), one or more polyisocyanates (N), optionally one or more catalysts, and optionally one or more solvents into a flask together;

procedure 2) procedure in which one or more active hydrogen group-containing compounds (H), optionally one or more catalysts, and optionally one or more solvents are charged into a flask, and one or more polyisocyanates (N) are added dropwise thereto, and the like.

In the polymerization method of the procedure 1), the reaction may partially progress rapidly, and a polymer having a low branching degree may be formed as a main component, or a gel may be formed. On the other hand, in the polymerization method of the procedure 2), the reaction can be controlled gently, and a polymer having a preferable branching degree can be easily produced. Therefore, the polymerization method of the procedure 2) is more preferable.

In the case of using a plurality of active hydrogen group-containing compounds (H) and/or polyisocyanates (N), the reaction may be carried out in multiple stages.

For example, in the reaction example shown in fig. 3, when a relatively high-branched polyol (PO1), a relatively low-branched polyol (PO2), and a relatively low-branched polyisocyanate (PI1) are reacted together, there is a high possibility that a prepolymer in a branched state is formed between the relatively high-branched prepolymer (PP1) and the relatively low-branched prepolymer (PP 2). By reacting a relatively high branched polyol (PO1) with a relatively low branched polyisocyanate (P11) first and then with a relatively low branched polyol (PO2), a relatively high branched prepolymer is readily obtained.

The reaction temperature when the catalyst is used is preferably less than 100 ℃, more preferably 50 to 95 ℃, and particularly preferably 60 to 85 ℃. If the reaction temperature is 100 ℃ or higher, the following concerns may arise: it is difficult to control the reaction rate, polymerization stability, etc., and it is difficult to produce a hydroxyl-terminated Urethane Prepolymer (UPH) having a desired molecular weight. The reaction temperature when no catalyst is used is preferably 100 ℃ or higher, more preferably 110 ℃ or higher.

(polyfunctional isocyanate Compound (I))

As the polyfunctional isocyanate compound (I), known polyfunctional isocyanate compounds (I) can be used, and compounds exemplified as the polyisocyanate (N) which is a raw material of the hydroxyl-terminated Urethane Prepolymer (UPH) (specifically, aromatic polyisocyanate, aliphatic polyisocyanate, aromatic aliphatic polyisocyanate, alicyclic polyisocyanate, and trimethylolpropane adduct/biuret/urea/trimer thereof) can be used.

The blending amount of the polyfunctional isocyanate compound (I) is not particularly limited. The raw material compounding ratio is preferably determined so that the ratio (NCO/H ratio) of the number of moles of isocyanate groups (NCO) in the polyisocyanate (I) to the total number of moles of active hydrogen groups (H) in the hydroxyl-terminated Urethane Prepolymer (UPH) is 0.20 to 4.00, preferably 0.40 to 3.00.

(plasticizer (P))

The adhesive of the present invention may further contain one or more plasticizers (P) as necessary from the viewpoint of reducing the adhesive force of the adhesive layer and improving the wettability. The plasticizer (P) is not particularly limited, and is preferably an organic acid ester from the viewpoint of compatibility with other components and the like.

The content of the plasticizer (P) is preferably 10 parts by mass or more with respect to 100 parts by mass of the hydroxyl-terminated Urethane Prepolymer (UPH). The upper limit of the content of the plasticizer (P) is not particularly limited, and is preferably 300 parts by mass or less, and more preferably 150 parts by mass or less. When the content of the plasticizer (P) is within the above range, removability becomes good.

Examples of esters of mono-or polybasic acids with alcohols include: isostearyl laurate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isostearyl palmitate, isocetyl stearate, octyldodecyl oleate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, diisodecyl adipate, diisostearyl adipate, dibutyl sebacate, diisocetyl sebacate, tributyl acetylcitrate, tributyl trimellitate, trioctyl trimellitate, trihexyl trimellitate, triolenyl trimellitate, and triisocetyl trimellitate.

Examples of esters of other acids with alcohols include: esters of unsaturated fatty acids or branched acids such as myristoleic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, and isostearic acid with alcohols such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, and sorbitan.

Examples of esters of mono-or polybasic acids with polyalkylene glycols include: polyethylene glycol dihexanoate, polyethylene glycol di-2-ethylhexanoate, polyethylene glycol dilaurate, polyethylene glycol dioleate, and diethylene glycol monomethyl adipate.

The molecular weight (formula weight or Mn) of the organic acid ester is preferably 250 to 1,000, more preferably 400 to 900, and particularly preferably 500 to 850, from the viewpoint of improving wettability. When the molecular weight is 250 or more, the heat resistance of the adhesive layer is good, and when the molecular weight is 1,000 or less, the wettability of the adhesive is good.

(solvent)

The adhesives of the invention may optionally contain more than one solvent. As the solvent, known solvents can be used, and there can be mentioned: methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, and the like. From the viewpoints of solubility of the hydroxyl-terminated Urethane Prepolymer (UPH), boiling point of the solvent, and the like, ethyl acetate, toluene, and the like are particularly preferable.

(anti-deterioration agent)

The adhesive of the present invention may optionally contain more than one anti-deterioration agent. This can suppress deterioration of various properties due to long-term use of the adhesive layer. As the deterioration preventing agent, there can be mentioned: hydrolysis resistance agents, antioxidants, ultraviolet absorbers, light stabilizers, and the like.

< hydrolysis resistance agent >

In the case where a carboxyl group is generated by hydrolysis of the adhesive layer under (moist) heat environment or the like, a hydrolysis resistant agent may be used for blocking the carboxyl group. As hydrolysis resistance agents, there can be mentioned: carbodiimide, oxazoline, and epoxy. Among them, a carbodiimide type is preferable from the viewpoint of the hydrolysis suppressing effect.

The carbodiimide-based hydrolysis resistance agent is a compound having one or more carbodiimide groups in one molecule.

Examples of the monocarbodiimide compound include: dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, diphenylcarbodiimide, and naphthylcarbodiimide, etc.

The polycarbodiimide compound may be produced by subjecting a diisocyanate to a decarbonylation condensation reaction in the presence of a carbodiimidization catalyst. Examples of the diisocyanate include: 4, 4 ' -diphenylmethane diisocyanate, 3 ' -dimethoxy-4, 4 ' -diphenylmethane diisocyanate, 3 ' -dimethyl-4, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylether diisocyanate, 3 ' -dimethyl-4, 4 ' -diphenylether diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1-methoxyphenyl-2, 4-diisocyanate, isophorone diisocyanate, 4 ' -dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, and the like. Examples of the carbodiimidization catalyst include: and phospholene oxides such as 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, and 3-phospholene isomers thereof.

Examples of the oxazoline-based hydrolysis resistance agent include: 2, 2 '-o-phenylbis (2-oxazoline), 2' -m-phenylbis (2-oxazoline), 2 '-p-phenylbis (4-methyl-2-oxazoline), 2' -m-phenylbis (4-methyl-2-oxazoline), 2 '-p-phenylbis (4, 4' -dimethyl-2-oxazoline), 2 '-m-phenylbis (4, 4' -dimethyl-2-oxazoline), 2 '-ethylidenebis (2-oxazoline), 2' -tetramethylenebis (2-oxazoline), 2 '-hexamethylenebis (2-oxazoline), 2' -octamethylenebis (2-oxazoline), 2, 2 '-ethylenebis (4-methyl-2-oxazoline), and 2, 2' -diphenylenebis (2-oxazoline).

Examples of the epoxy hydrolysis-resistant agent include: diglycidyl ethers of aliphatic diols such as 1, 6-hexanediol, neopentyl glycol, and polyalkylene glycol; polyglycidyl ethers of aliphatic polyhydric alcohols such as sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, and trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol; diglycidyl esters or polyglycidyl esters of aliphatic or aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid; diglycidyl ethers or polyglycidyl ethers of polyhydric phenols such as resorcinol, bis- (p-hydroxyphenyl) methane, 2, 2-bis- (p-hydroxyphenyl) propane, tris- (p-hydroxyphenyl) methane, and 1, 1, 2, 2-tetrakis (p-hydroxyphenyl) ethane; n-glycidyl derivatives of amines such as N, N-diglycidylaniline, N-diglycidyltoluidine, and N, N' -tetraglycidyl-bis- (p-aminophenyl) methane; triglycidyl derivatives of aminophenols; triglycidyl tris (2-hydroxyethyl) isocyanurate, and triglycidyl isocyanurate; epoxy resins such as o-cresol type epoxy resins and phenol novolac type epoxy resins.

The amount of the hydrolysis resistant agent to be added is not particularly limited, and is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4.5 parts by mass, and particularly preferably 0.5 to 3 parts by mass, based on 100 parts by mass of the hydroxyl-terminated Urethane Prepolymer (UPH).

< antioxidant >

Examples of the antioxidant include a radical scavenger and a peroxide decomposer. Examples of the radical scavenger include phenol compounds and amine compounds. Examples of the peroxide decomposer include sulfur compounds and phosphorus compounds.

Examples of the phenolic compound include: 2, 6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2, 6-di-tert-butyl-4-ethylphenol, stearyl β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, 2 '-methylenebis (4-methyl-6-tert-butylphenol), 2' -methylenebis (4-ethyl-6-tert-butylphenol), 4 '-thiobis (3-methyl-6-tert-butylphenol), 4' -butylidenebis (3-methyl-6-tert-butylphenol), 3, 9-bis [1, 1-dimethyl-2- [ β - (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy ] ethyl ]2, 4, 8, 10-tetraoxaspiro [5, 5] undecane, phenylpropionic acid, 3, 5-bis (1, 1-dimethylethyl) -4-hydroxy-, C7-C9 side chain alkyl ester, 1, 3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1, 3, 5-trimethyl-2, 4, 6-tris (3, 5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [ methylene-3- (3 ', 5' -di-t-butyl-4 '-hydroxyphenyl) propionate ] methane, ethylene glycol bis [3, 3' -bis- (4 '-hydroxy-3' -t-butylphenyl) butyrate ], 1, 3, 5-tris (3 ', 5 ' -di-tert-butyl-4 ' -hydroxybenzyl) -S-triazine-2, 4, 6- (1H, 3H, 5H) trione, tocopherol, and the like.

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

Examples of the phosphorus-based compound include: triphenyl phosphite, diphenylisodecyl phosphite, 4' -butylidene-bis (3-methyl-6-tert-butylphenyl ditridecyl) phosphite, cycloneopentanetetraylbis (octadecyl phosphite), tris (nonylphenyl) phosphite, tris (monononylphenyl) phosphite, tris (dinonylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3, 5-di-tert-butyl-4-hydroxybenzyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene, phosphorus, Tris (2, 4-di-tert-butylphenyl) phosphite, cycloneopentanetetraylbis (2, 6-di-tert-butyl-4-methylphenyl) phosphite, and octyl 2, 2-methylenebis (4, 6-di-tert-butylphenyl) phosphite.

Thermal deterioration of the hydroxyl-terminated Urethane Prepolymer (UPH) can be prevented by using an antioxidant.

The amount of the antioxidant to be added is not particularly limited, but is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and particularly preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the hydroxyl-terminated Urethane Prepolymer (UPH).

As the antioxidant, from the viewpoint of stability and antioxidant effect, it is preferable to use one or more phenol compounds as the radical scavenger, and more preferably to use one or more phenol compounds as the radical scavenger in combination with one or more phosphorus compounds as the peroxide decomposer. In addition, it is particularly preferable to use a phenol compound as a radical scavenger and a phosphorus compound as a peroxide decomposer in combination as the antioxidant, and to use these antioxidants and the hydrolysis resistance agent in combination.

< ultraviolet absorber >

Examples of the ultraviolet absorber include: benzophenone-based compounds, benzotriazole-based compounds, salicylic acid-based compounds, oxalanilide-based compounds, cyanoacrylate-based compounds, triazine-based compounds, and the like.

The amount of the ultraviolet absorber to be added can be suitably designed within a range that does not inhibit the initiation and progress of polymerization of the radical polymerizable Monomer (MX) by irradiation with active energy rays and does not easily initiate the reaction of the radical polymerizable Monomer (MX) by light of a fluorescent lamp or ambient light such as sunlight. When the radical polymerizable Monomer (MX) is ultraviolet-curable, the amount of the ultraviolet absorber to be added is designed according to the kind of the ultraviolet absorber, the wavelength range of ultraviolet rays to be irradiated to the adhesive layer, and the cumulative amount of light. The amount of the ultraviolet absorber added is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 2.5 parts by mass, and particularly preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the hydroxyl-terminated Urethane Prepolymer (UPH).

< light stabilizer >

Examples of the light stabilizer include hindered amine compounds and hindered piperidine compounds. The amount of the light stabilizer to be added is not particularly limited, but is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1.5 parts by mass, and particularly preferably 0.2 to 1 part by mass, based on 100 parts by mass of the hydroxyl-terminated Urethane Prepolymer (UPH).

(antistatic Agent (AS))

The adhesive of the present invention may optionally contain more than one antistatic Agent (AS). AS antistatic Agents (AS) there may be mentioned: inorganic salts, ionic liquids, ionic solids, surfactants, and the like, and among them, ionic liquids and ionic solids are preferable. The "ionic liquid" is also referred to as an ambient temperature molten salt, and is a salt having fluidity at 25 ℃.

Examples of the inorganic salt include: sodium chloride, potassium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, potassium nitrate, sodium carbonate, sodium thiocyanate and the like.

Examples of the ionic liquid containing an imidazolium ion include: 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1, 3-dimethylimidazolium bis (trifluoromethylsulfonyl) imide, and 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide.

Examples of the ionic liquid containing a pyridinium ion include: 1-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-butylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexylpyridinium bis (trifluoromethylsulfonyl) imide, 1-octylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide, 1-methylpyridinium bis (perfluoroethylsulfonyl) imide, and 1-methylpyridinium bis (perfluorobutylsulfonyl) imide, and the like.

Examples of the ionic liquid containing an ammonium ion include: 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, tri-N-butylmethylammonium bis (trifluoromethanesulfonyl) imide, and the like.

Further, commercially available ionic liquids such as pyrrolidinium salts, phosphonium salts, and sulfonium salts can be suitably used.

The ionic solid is a salt of a cation and an anion, as in the case of the ionic liquid, but shows a solid state at 25 ℃ under normal pressure. The cation is preferably an alkali metal ion, a phosphonium ion, a pyridinium ion, an ammonium ion, or the like.

Examples of the ionic solid containing an alkali metal ion include: lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethylsulfonyl imide, lithium bis-pentafluoroethylsulfonyl imide, lithium bis-heptafluoropropylsulfonyl imide, lithium bis-nonane fluorobutylsulfonyl imide, sodium bis-fluorosulfonyl imide, sodium bis-trifluoromethylsulfonyl imide, sodium bis-pentafluoroethylsulfonyl imide, sodium bis-heptafluoropropylsulfonyl imide, sodium bis-nonane fluorobutylsulfonyl imide, potassium bis-fluorosulfonyl imide, potassium bis-trifluoromethylsulfonyl imide, potassium bis-pentafluoroethylsulfonyl imide, potassium bis-heptafluoropropylsulfonyl imide, and potassium bis-nonane fluorobutylsulfonyl imide, and the like.

Examples of the ionic solid containing a phosphonium ion include: tetrabutylphosphonium difluoride sulfonyl imide, tetrabutylphosphonium bistrifluoromethylsulfonyl imide, tetrabutylphosphonium bistrifluoroethylsulfonyl imide, tetrabutylphosphonium bistheptafluoropropylsulfonyl imide, tetrabutylphosphonium bistonofluoroalkylfluorobutylsulfonyl imide, tributylhexadecylphosphonium bistrifluorosulfonyl imide, tributylhexadecylphosphonium bistrifluoromethylsulfonyl imide, tributylhexadecylphosphonium bistrifluoroethylsulfonyl imide, tributylhexadecyl phosphonium bis-heptafluoropropylsulfonyl imide, tributylhexadecyl phosphonium bis-nonane fluorobutylsulfonyl imide, tetraoctyl phosphonium bis-fluorosulfonyl imide, tetraoctyl phosphonium bis-trifluoromethyl sulfonyl imide, tetraoctyl phosphonium bis-pentafluoroethylsulfonyl imide, tetraoctyl phosphonium bis-heptafluoropropylsulfonyl imide, and tetraoctyl phosphonium bis-nonane fluorobutylsulfonyl imide, and the like.

Examples of the ionic solid containing a pyridinium ion include: 1-hexadecyl-4-methylpyridinium difluorosulfonyl imide, 1-hexadecyl-4-methylpyridinium bistrifluoromethylsulfonyl imide, 1-hexadecyl-4-methylpyridinium dipentafluoroethylsulfonyl imide, 1-hexadecyl-4-methylpyridinium bispentafluoropropylsulfonyl imide, and 1-hexadecyl-4-methylpyridinium dinonylfluorobutylsulfonyl imide, and the like.

Examples of the ionic solid containing an ammonium ion include: lauryl trimethyl ammonium chloride, tributylmethyl bis (trifluoromethylsulfonyl) imide, tributylmethyl bis (pentafluoroethylsulfonyl) imide, tributylmethyl bis (heptafluoropropylsulfonyl) imide, tributylmethyl bis (nonane fluorobutylsulfonyl) imide, octyl tributylbis (trifluoromethylsulfonyl) imide, octyl tributyl bis (pentafluoroethylsulfonyl) imide, octyl tributyl bis (heptafluoropropylsulfonyl) imide, octyl tributyl bis (nonane fluorobutylsulfonyl) imide, tetrabutyl bis (fluorosulfonyl) imide, tetrabutyl bis (trifluoromethyl sulfonyl) imide, tetrabutyl bis (pentafluoroethylsulfonyl) imide, tetrabutyl bis (heptafluoropropylsulfonyl) imide, tetrabutyl bis (nonane fluorobutylsulfonyl) imide, and the like.

In addition, known ionic solids having cations such as pyrrolidinium ion, imidazolium ion, and sulfonium ion can be suitably used.

The surfactant includes a nonionic surfactant and an anionic surfactant, and both types are classified into a low-molecular surfactant and a high-molecular surfactant.

Examples of the nonionic low-molecular-weight surfactant include: glycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine fatty acid ester, and fatty acid diethanolamide.

Examples of the anionic low-molecular-weight surfactant include: alkyl sulfonates, alkylbenzene sulfonates, and alkyl phosphates, and the like.

Examples of the amphoteric low-molecular-weight surfactant include alkyl betaines and alkyl imidazolium betaines.

Examples of the nonionic polymer surfactant include: polyether ester amide type, ethylene oxide-epichlorohydrin type, polyether ester type, and the like.

Examples of the anionic polymeric surfactant include polystyrene sulfonic acid type surfactants.

Examples of the amphoteric polymer surfactant include: and amino acid type amphoteric surfactants such as higher alkyl aminopropionates, and betaine type amphoteric surfactants such as higher alkyl dimethyl betaines and higher alkyl dihydroxyethyl betaines.

The amount of the antistatic Agent (AS) added is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, per 100 parts by mass of the hydroxyl-terminated Urethane Prepolymer (UPH).

(leveling agent)

The adhesive of the present invention may optionally contain a leveling agent. By adding the leveling agent, the leveling property of the adhesive layer can be improved. As the leveling agent, there can be mentioned: acrylic leveling agents, fluorine leveling agents, silicone leveling agents, and the like. From the viewpoint of suppressing contamination of an adherend after the adhesive sheet is peeled off again, an acrylic leveling agent or the like is preferable.

The amount of the leveling agent is not particularly limited, and is preferably 0.001 to 2 parts by mass, more preferably 0.01 to 1.5 parts by mass, and particularly preferably 0.1 to 1 part by mass, based on 100 parts by mass of the hydroxyl-terminated Urethane Prepolymer (UPH), from the viewpoints of suppressing contamination of an adherend after re-peeling of the adhesive sheet and improving the leveling property of the adhesive layer.

(other optional ingredients)

The adhesive of the present invention may optionally contain other optional components within a range not impairing the effects of the present invention. As other optional components, there may be mentioned: a catalyst, a resin other than the urethane resin, a filler (talc, calcium carbonate, titanium oxide, or the like), a metal powder, a colorant (pigment, or the like), a foil, a softening agent, a conductive agent, a silane coupling agent, a lubricant, an anticorrosive agent, a heat-resistant stabilizer, a weather-resistant stabilizer, a polymerization inhibitor, an antifoaming agent, or the like.

When the adhesive of the present invention contains a catalyst, it is preferable to add a known catalyst action inhibitor such as acetylacetone for the purpose of increasing the pot life of the adhesive.

(mixing ratio)

The adhesive of the present invention contains one or more hydroxyl-terminated Urethane Prepolymers (UPH) having a specific branching degree α and one or more polyfunctional isocyanate compounds (I) as essential components, and further contains one or more optional components as required. The blending ratio of these is not particularly limited, and preferable blending ratios are as follows.

The amount of the one or more polyfunctional isocyanate compounds (I) is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass, and particularly preferably 8 to 20 parts by mass, relative to 100 parts by mass of the one or more hydroxyl-terminated Urethane Prepolymers (UPH). When the amount of the one or more polyfunctional isocyanate compounds (I) is 1 part by mass or more, the cohesive force of the adhesive layer becomes good, and when it is 30 parts by mass or less, the pot life becomes good.

(method for producing adhesive)

The method for producing the adhesive of the present invention is not particularly limited.

The adhesive of the present invention can be produced by adding and mixing one or more polyfunctional isocyanate compounds (I) and optionally one or more other optional components to one or more hydroxyl-terminated Urethane Prepolymers (UPH) synthesized by the above method (which may be in the form of a solution containing a solvent).

[ adhesive sheet ]

The adhesive sheet of the present invention includes a substrate sheet and an adhesive layer containing a cured product of the adhesive of the present invention. The adhesive layer may be formed on one or both sides of the substrate sheet. The exposed surface of the adhesive layer may be covered with a release sheet as necessary. Further, the release sheet may be peeled off before the adhesive sheet is attached to the adherend.

Fig. 1 is a schematic cross-sectional view of an adhesive sheet according to a first embodiment of 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 one side of a base sheet.

Fig. 2 is a schematic cross-sectional view of an adhesive sheet according to a second embodiment of the present invention. In fig. 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 release sheets. The adhesive sheet 20 is a double-sided adhesive sheet in which adhesive layers are formed on both sides of a base sheet.

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

The structural resin of the resin sheet is not particularly limited, and includes: ester resins such as polyethylene terephthalate (PET); olefin resins such as Polyethylene (PE) and polypropylene (PP); vinyl resins such as polyvinyl chloride; amide resins such as nylon 66; urethane resin (including foam); combinations of these, and the like.

The thickness of the resin sheet other than the polyurethane sheet is not particularly limited, but is preferably 15 to 300 μm. The thickness of the polyurethane sheet (including the foam) is not particularly limited, and is preferably 20 μm to 50,000 μm.

The paper is not particularly limited, and includes: plain paper, coated paper, and the like.

The structural metal of the metal foil is not particularly limited, and includes: aluminum, copper, combinations of these, and the like.

The release sheet is not particularly limited, and a known release sheet obtained by subjecting the surface of a substrate sheet such as a resin sheet or paper to a known release treatment such as coating with a release agent can be used.

[ method for producing adhesive sheet ]

The adhesive sheet can be manufactured by a known method.

First, the adhesive of the present invention is applied to the surface of a substrate sheet to form a coating layer containing the adhesive of the present invention. The coating method may be any known method, and examples thereof include: a roll coater method, a comma coater method, a die coater method, a reverse coater method, a screen printing method, a gravure coater method, and the like.

Next, the coating layer is dried and cured to form an adhesive layer containing a cured product of the adhesive of the present invention. The heating and drying temperature is not particularly limited, but is preferably about 60 ℃ to 150 ℃. The thickness of the adhesive layer (thickness after drying) varies depending on the application, but is preferably 0.1 to 200 μm.

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

In this manner, a single-sided adhesive sheet can be produced.

By performing the above operation on both sides, a double-sided adhesive sheet can be manufactured.

In contrast to the above method, the adhesive of the present invention may be applied to the surface of a release sheet to form a coating layer containing the adhesive of the present invention, the coating layer may be dried and cured to form an adhesive layer containing a cured product of the adhesive of the present invention, and a substrate sheet may be laminated on the exposed surface of the adhesive layer.

The method for producing an adhesive sheet preferably includes: a coating step of coating an adhesive on a base sheet; a heating step of forming an adhesive layer containing a cured product of an adhesive by heating and drying the formed coating layer; a winding step of winding the obtained adhesive sheet around a core to form an adhesive sheet roll; and a curing step of curing the adhesive sheet roller.

As described above, according to the present invention, it is possible to provide an adhesive which has good initial curability, can form an adhesive layer which suppresses an increase in adhesive force even when exposed to a thermal environment, particularly a moist thermal environment, and has good removability, and an adhesive sheet using the adhesive.

[ use ]

The adhesive sheet of the present invention can be used in the form of a tape, a label, a sheet, a double-sided tape, or the like. The adhesive sheet of the present invention can be preferably used as a surface protective sheet, a cosmetic sheet, an anti-slip sheet, and the like.

In the present specification, unless otherwise specified, "sheet" includes "film" and "tape".

Flat panel displays such as Liquid Crystal Displays (LCDs) and organic electroluminescent displays (OELDs), and touch panel displays in which the flat panel displays and the touch panel are combined are widely used in electronic devices such as Televisions (TVs), Personal Computers (PCs), mobile phones, and portable information terminals.

The adhesive sheet of the present invention can be preferably used as a surface protective sheet for flat panel displays, touch panel displays (these are also collectively referred to simply as "displays"), substrates produced or used in the production steps thereof (glass substrates, and Indium Tin Oxide (ITO)/glass substrates having an ITO film formed on a glass substrate, etc.), optical members, and the like.

Examples

Synthetic examples, examples of the present invention, and comparative examples are described below. In the following description, "part" means part by mass, "%" means% by mass, and "RH" means relative humidity unless otherwise specified. The unit of the blending amount in the table is "part by mass" unless otherwise noted. Unless otherwise specified, the amount of components other than the solvent is a nonvolatile component equivalent.

[ evaluation items and evaluation methods of materials or hydroxyl-terminated urethane prepolymers ]

The evaluation items and evaluation methods of the materials and the hydroxyl-terminated urethane prepolymers are as follows.

(Mw、Mn)

The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by a Gel Permeation Chromatography (GPC) method. The measurement conditions were as follows. Furthermore, Mw and Mn are both polystyrene equivalent values.

The device comprises the following steps: shimadzu excellence (Shimadzu project) (manufactured by Shimadzu corporation),

Pipe column: three SHODEX L

LF-804 (manufactured by Showa Denko K.K.) connected in series,

A detector: a differential refractive index detector,

Solvent: tetrahydrofuran (THF),

Flow rate: 1mL/min,

Temperature of the solvent: at 40 deg.C,

Sample concentration: 0.2 percent of,

Sample injection amount: 200 μ L.

(degree of branching. alpha.)

The degree of branching α was measured using a device (GPC-MALS-VISCO) in which a multi-angle light scattering detector (MALS) was combined with a viscosity detector (VISCO) and a Gel Permeation Chromatograph (GPC).

(viscosity of hydroxyl-terminated urethane prepolymer solution)

The viscosity of the hydroxyl-terminated urethane prepolymer solution at 25 ℃ was measured by placing the solution in a glass bottle with a cap immediately after the preparation, immersing the solution in a water bath at 25 ℃ and then measuring the viscosity after 1 hour. The viscosity was measured using a B-type viscometer ("TVB 10-type viscometer" manufactured by eastern mechanical industries, inc.).

(nonvolatile component)

The nonvolatile content of the hydroxyl-terminated urethane prepolymer solution was determined from the change in mass after drying relative to that before drying, after heating and drying about 1g of the sample at 120 ℃ for 20 minutes.

[ Synthesis example of polyol ]

(Synthesis example Z-1)

An autoclave equipped with a stirrer and a temperature controller was charged with 100.0 parts of butylethylpropylene glycol (BEPD) as a first component and 4.0 parts of potassium hydroxide, heated to 100 ℃, and 150.0 parts of Propylene Oxide (PO) as a second component was continuously charged under stirring.

To the obtained reaction product, 40.0 parts of water and 40.0 parts of an alkali adsorbent "Kyoward (Kyoward) 600" (manufactured by Kyowa chemical industries Co., Ltd.) were added, and they were stirred and mixed at 90 ℃ for 1 hour. Thereafter, the added alkali adsorbent was removed using a filter with filter paper laid thereon. The reaction product passed through the filter paper was dehydrated at 130 ℃ under a pressure of 2.7 kPa.

As described above, a polyether polyol (HX-1) having a number average molecular weight (Mn) of 400, an average number of functional groups of 2 and a branching degree. alpha. of 0.45 was obtained. The raw material composition, and the kind and characteristics of the obtained polyol are shown in tables 1-1 and 1-2.

(Synthesis examples Z-3 and Z-11)

A polyol was obtained in the same manner as in Synthesis example z-1, except that the kinds and amounts of the first component and the second component were changed. The raw material composition, and the kind and characteristics of the obtained polyol are shown in tables 1-1 and 1-2.

(Synthesis example Z-2)

An autoclave equipped with a stirring device and a temperature control device was charged with 100 parts of terephthalic acid (TPA) as a first component, 27 parts of Trimethylolpropane (TMP) as a second component, and 74 parts of 1, 9-Nonanediol (ND) as a third component. The reaction mixture was heated to 200 ℃ under a nitrogen atmosphere at normal pressure, and the esterification reaction was carried out while removing the generated water by distillation out of the system. At a point when the removal of the generated water by distillation became small, 0.01 part of tetraisopropyl titanate was added, and the reaction was continued while reducing the pressure by a vacuum pump, thereby obtaining a polyester polyol (HX-2) having a number average molecular weight (Mn) of 1500, an average number of functional groups of 3, and a branching degree alpha of 0.35.

(Synthesis examples Z-7, Z-10 and Z-16)

A polyol was obtained in the same manner as in synthesis example Z-2, except that the kinds and amounts of the first component, the second component and the third component were changed. The raw material composition, and the kind and characteristics of the obtained polyol are shown in tables 1-1 and 1-2.

(Synthesis example Z-4)

An autoclave equipped with a stirring device and a temperature control device was charged with 100.0 parts of glycerin and 4.0 parts of potassium hydroxide as first components, heated to 100 ℃, and 334 parts of 1, 2-butylene oxide (1, 2-BO) as a second component was continuously charged under stirring.

The reaction product was charged into an autoclave equipped with a stirrer and a temperature controller, and 0.10 part of a zinc hexacyanocobaltate catalyst was further charged, and then the temperature in the reactor was increased to 130 ℃, and 282 parts of 1, 2-butylene oxide (1, 2-BO) as a third component (10 mass% of the total amount used) were added under stirring.

After the reaction for 2 hours and the activation of the catalyst, 2538 parts (90% by mass of the total amount used) of 1, 2-butylene oxide (1, 2-BO) as a third component was continuously added at 100 ℃ and mixed and stirred at 95 ℃ until the pressure became constant. The resulting mixture was vacuum deplating at 100 deg.f for 0.5 hours to remove unreacted third component from the reactor.

As described above, a polyether polyol (HX-S-2) having a number average molecular weight (Mn) of 3000, an average number of functional groups of 2, and a branching degree. alpha. of 0.05 was obtained. The raw material composition and the characteristics of the obtained polyol are shown in tables 1-1 and 1-2.

(Synthesis examples Z-5, Z-6, Z-9, Z-12 and Z-15)

A polyol was obtained in the same manner as in synthesis example Z-4, except that the kinds and amounts of the first component, the second component and the third component were changed. The raw material composition, and the kind and characteristics of the obtained polyol are shown in tables 1-1 and 1-2.

(Synthesis example Z-8)

A round-bottomed flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a condenser was charged with 1854g of polycarbonate diol (available from Daicel chemical industries, Ltd.; trade name: CD220, molecular weight 2011, hydroxyl value 55.8), 21g of trimethylolpropane, 126g of pentaerythritol, and 0.08g of tetrabutyltitanate as a catalyst. The mixture was heated while stirring at normal pressure. The reaction temperature was gradually increased to 220 ℃ and then maintained for 8 hours, thereby carrying out the reaction.

Sampling was carried out as needed during the reaction, and the residual diol component (1, 6-hexanediol in this case) and triol component (trimethylolpropane in this case) were quantified by gas chromatography, and it was confirmed that the transesterification reaction reached an equilibrium state, and the reaction was terminated.

As described above, a polycarbonate polyol (HX-S-6) having a number average molecular weight (Mn) of 1000, an average number of functional groups of 3, and a degree of branching α of 0.05 was obtained. The raw material composition, and the kind and characteristics of the obtained polyol are shown in tables 1-1 and 1-2.

The following compounds are shown in tables 1-1 and 1-2.

BEPD: butyl ethyl propylene glycol,

TPA: terephthalic acid,

AA: adipic acid,

PG: propylene glycol,

IPA: isophthalic acid,

PO: propylene oxide,

TMP: trimethylolpropane,

1, 2-BO: 1, 2-butylene oxide,

EO: ethylene oxide,

THF: tetrahydrofuran, tetrahydrofuran,

PD-9: 2, 4-diethyl-1, 5-pentanediol,

ND: 1, 9-nonanediol,

MPD: 2-methylpentane-2, 4-diol,

CD 220: polycarbonate diol (available under the trade name CD220, molecular weight 2011, hydroxyl value 55.8, from Daicel chemical industries, Ltd.),

PET: pentaerythritol.

[ Material ]

The materials used are as follows.

The kind, number of functional groups, Mn, average number of functional groups, and branching degree α of the active hydrogen group-containing compound (HX) and the active hydrogen group-containing compound (HY) to be used are shown in table 1-2. The kind, number of functional groups and Mn of the polyisocyanate (N) used are shown in Table 1-2.

< Compound containing active Hydrogen group (HX) >

(HX-1): a polyether polyol.

(HX-2): a polyester polyol.

(HX-S-1): a polycaprolactone polyol.

(HX-S-2): a polyether polyol.

(HX-S-3): a polyether polyol.

(HX-S-4): a polyether polyol.

(HX-S-5): a polyester polyol.

(HX-S-6): a polycarbonate polyol.

(HX-S-7): polyether polyol, "DK polyol (DK polyol) G480" manufactured by the first industrial pharmaceutical company.

(HX-S-8): polyether polyol, "Adeka polyether (Adeka polyether) AM-302" manufactured by Adeka (ADEKA) Inc.

< Compound containing active Hydrogen group (HY) >

(HY-1): a polyether polyol.

(HY-2): a polyester polyol.

(HY-L-1): a polyether polyol.

(HY-L-2): a polyether polyol.

(HY-L-3): a polyether polyol.

(HY-L-4): a polyether polyol.

(HY-L-5): a polyether polyol.

(HY-L-6): a polyester polyol.

(HY-L-7): polyether polyol, "poly gardner" D-100A "manufactured by first industrial pharmaceutical company.

(HY-L-8): polyester polyol, "Korea polyol (Kurarypolyol) P-1010" manufactured by Korea (Kuraray).

(HY-L-9): polyether polyol, "poly gardner" D-40 "manufactured by first industrial pharmaceutical company.

< polyisocyanate (N) >

(N-1): HDI, hexamethylene diisocyanate, Korsakochu Urethane (Sumika Covestro Urethane), Desmodur (Desmodur) H.

(N-2): IPDI, isophorone diisocyanate, Kanghua Korsakochu carbamate (Sumika Covestro Urethane), Desmodur (Desmodur) I.

(N-3): TDI, tolylene diisocyanate (a mixture of 2, 4-tolylene diisocyanate (80% by mass) and 2, 6-tolylene diisocyanate (20% by mass), manufactured by Tosoh corporation, Cronenate T-80.

(N-4): HDI urethanate, Sumido (Sumidur) N-3300, manufactured by Sumika Bayer Urethane, Hexamethylene Diisocyanate (HDI)/isocyanurate.

[ tables 1-1]

[ tables 1-2]

< polyfunctional isocyanate Compound (I) >

(I-1) HDI adduct, cronate HL, manufactured by Tosoh corporation, Hexamethylene Diisocyanate (HDI)/Trimethylolpropane (TMP) adduct.

(I-2) HDI urethanate, Sumido (Sumidur) N-3300, manufactured by Sumika Bayer Urethane, Hexamethylene Diisocyanate (HDI)/isocyanurate.

< antioxidant (O) >

(O-1): lyocell (IRGANOX)1010, pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], a phenolic antioxidant, and BASF.

< plasticizer (P) >

(P-1): adisk RS700 (Adeka sizer), polyether ester plasticizer, adisk (Adeka).

(P-2): elapipalu (Exceparl) MOL, methyl oleate, manufactured by Kao corporation.

< antistatic Agent (AS) >

(AS-1): ionic liquid, tri-n-butyl methyl ammonium bis (trifluoromethanesulfonyl) imide.

[ Synthesis example of a solution of a hydroxyl-terminated Urethane Prepolymer (UPH) ]

(Synthesis example 1) one-stage dropping method (method 1)

80.0 parts by mass of an active hydrogen group-containing compound (HX-S-1), 20.0 parts by mass of an active hydrogen group-containing compound (HY-L-5), 42.8 parts by mass of toluene, 0.020 parts by mass of dioctyltin dilaurate as a catalyst and 0.008 parts by mass of tin 2-ethylhexanoate were charged and mixed in a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer and a dropping funnel. Thereafter, the content liquid was gradually heated to 80 ℃.

25.0 parts by mass of polyisocyanate (N-1) and 24.5 parts by mass of toluene were charged into and mixed with a dropping funnel, and the mixture was dropped into a four-necked flask over 1 hour. After the completion of the dropwise addition, the reaction was carried out for 1 hour.

The ratio (NCO/H ratio) of the number of moles of isocyanate groups in the polyisocyanate (N) used in the reaction to the total number of moles of active hydrogen groups in all the active hydrogen group-containing compounds (H) used in the reaction was 0.78.

After the disappearance of the remaining isocyanate group was confirmed by infrared spectroscopic analysis (IR analysis), the reaction was terminated by cooling the content liquid to 40 ℃. Finally, 0.56 part by mass of acetylacetone was added.

As described above, a colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-1) having a nonvolatile content of 65% and a viscosity of 3200cps was obtained. The main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in Table 2-1. In each of the examples in tables 2-1, 2-2, 3-1, 3-2 and 4, the conditions not shown in the tables are common conditions.

(Synthesis examples 2 to 14, 19 to 33) one-stage dropping method (method 1)

Colorless and transparent solutions of hydroxyl-terminated urethane prepolymer (UPH-2) to hydroxyl-terminated urethane prepolymer (UPH-14), hydroxyl-terminated urethane prepolymer (UPH-19) to hydroxyl-terminated urethane prepolymer (UPH-33) were obtained in the same manner as in Synthesis example 1 except that the kind of active hydrogen group-containing compound (H), the kind of polyisocyanate (N) and the blending ratio thereof were changed in Synthesis examples 2 to 14 and 19 to 33. In each synthesis example, the main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in tables 2-1, 2-2, 3-1 and 3-2.

(Synthesis example 15) Co-charging method (method 2)

Into a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel were charged and mixed 32.0 parts by mass of an active hydrogen group-containing compound (HX-S-7), 68.0 parts by mass of an active hydrogen group-containing compound (HY-L-7), 26.0 parts by mass of a polyisocyanate (N-1), 67.8 parts by mass of toluene and 0.020 parts by mass of dioctyltin dilaurate as a catalyst. Thereafter, the content liquid was heated to 80 ℃ and reacted for 3 hours.

The ratio of the number of moles of isocyanate groups in the polyisocyanate (N) used in the reaction to the total number of moles of active hydrogen groups in all the active hydrogen group-containing compounds (H) used in the reaction (NCO/H ratio) was 0.75.

As described above, a colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-15) having a nonvolatile content of 65% and a viscosity of 1800cps was obtained. The main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in Table 2-2.

(Synthesis examples 16 and 34) Loading method (method 2)

Colorless and transparent solutions of a hydroxyl-terminated urethane prepolymer (UPH-16) and a hydroxyl-terminated urethane prepolymer (UPH-34) were obtained in the same manner as in Synthesis example 15 except that the kind of the active hydrogen group-containing compound (H), the kind of the polyisocyanate (N), and the blending ratio thereof were changed in Synthesis examples 16 and 34. In each synthesis example, the main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in tables 2-2 and 3-2.

(Synthesis examples 41 and 42) Loading method (method 2)

Colorless and transparent solutions of a hydroxyl-terminated urethane prepolymer (UPC-41) and a hydroxyl-terminated urethane prepolymer (UPC-42) were obtained in the same manner as in Synthesis example 14 except that the kind of the active hydrogen group-containing compound (H), the kind of the polyisocyanate (N) and the compounding ratio thereof were changed in Synthesis examples 41 and 42. In each synthesis example, the main formulation composition, NCO/H ratio, and Mw and Mn and the degree of branching α of the obtained hydroxyl-terminated urethane prepolymer are shown in table 4.

Synthesis example 17 two-stage reaction method (method 3)

80.0 parts by mass of an active hydrogen group-containing compound (HX-S-2), 50.5 parts by mass of toluene, 0.020 parts by mass of dioctyltin dilaurate as a catalyst, and 0.008 parts by mass of tin 2-ethylhexanoate were charged into a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel and mixed. Thereafter, the content liquid was gradually heated to 80 ℃.

4.0 parts by mass of polyisocyanate (N-1) and 4.0 parts by mass of toluene were charged into and mixed with a dropping funnel, and the mixture was dropped into a four-necked flask over 1 hour. After the completion of the dropwise addition, the reaction was carried out for 1 hour.

After the disappearance of the remaining isocyanate groups was confirmed by infrared spectroscopic analysis (IR analysis), the content liquid was cooled to 60 ℃ or lower. After 20.0 parts by mass of an active hydrogen group-containing compound (HY-L-6) was added and mixed to the content liquid, the content liquid was gradually heated to 80 ℃.

1.5 parts by mass of polyisocyanate (N-1) and 3.0 parts by mass of toluene were charged into and mixed with a dropping funnel, and the mixture was dropped into a four-necked flask over 1 hour. After the completion of the dropwise addition, the reaction was carried out for 1 hour.

The ratio of the number of moles of isocyanate groups in the polyisocyanate (N) used in the reaction to the total number of moles of active hydrogen groups in all the active hydrogen group-containing compounds (H) used in the reaction (NCO/H ratio) was 0.65.

After the disappearance of the remaining isocyanate group was confirmed by infrared spectroscopic analysis (IR analysis), the reaction was terminated by cooling the content liquid to 40 ℃. Finally, 0.46 part by mass of acetylacetone was added.

As described above, a colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-17) having a nonvolatile content of 65% and a viscosity of 7000cps was obtained. The main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in Table 2-2.

Synthesis example 35 two-stage reaction method (method 3)

A colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-35) was obtained in the same manner as in synthesis example 17, except that the kind of the active hydrogen group-containing compound (H), the kind of the polyisocyanate (N), and the blending ratio thereof were changed in synthesis example 35. The main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in Table 3-2.

Synthesis example 18 two-stage reaction method (method 4)

20.0 parts by mass of an active hydrogen group-containing compound (HY-L-6), 50.5 parts by mass of toluene, 0.020 part by mass of dioctyltin dilaurate as a catalyst, and 0.008 part by mass of tin 2-ethylhexanoate were charged and mixed into a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel. Thereafter, the content liquid was gradually heated to 80 ℃.

After the disappearance of the remaining isocyanate groups was confirmed by infrared spectroscopic analysis (IR analysis), the content liquid was cooled to 60 ℃ or lower. 80.0 parts by mass of an active hydrogen group-containing compound (HX-S-2) was added to and mixed with the content liquid, and the content liquid was gradually heated to 80 ℃.

As described above, a colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-18) having a nonvolatile content of 65% and a viscosity of 2800cps was obtained. The main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in Table 2-2.

Synthesis example 36 two-stage reaction method (method 4)

A colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-36) was obtained in the same manner as in synthesis example 18, except that the kind of the active hydrogen group-containing compound (H), the kind of the polyisocyanate (N), and the blending ratio thereof were changed in synthesis example 36. The main formulation composition, NCO/H ratio, Mw and Mn of the obtained hydroxyl-terminated urethane prepolymer, and degree of branching α are shown in Table 3-2.

[ tables 2-2]

[ tables 3-2]

[ Table 4]

[ production of adhesive and adhesive sheet ]

(example 1)

A urethane adhesive was obtained by mixing 100 parts by mass of a solution of the hydroxyl-terminated urethane prepolymer (UPH-1) obtained in Synthesis example 1, 15 parts by mass of the polyfunctional isocyanate compound (I-1), 1 part by mass of the antioxidant (O-1), 15 parts by mass of the plasticizer (P-1), and 100 parts by mass of ethyl acetate as a solvent, and stirring the mixture with a disperser. The amounts of the respective materials other than the solvent used are expressed as nonvolatile components (the same applies to the other examples and comparative examples). The main formulation compositions are shown in table 5.

A50 μm-thick polyethylene terephthalate film (PET film, produced by Lumiror T-60: Toray corporation) was prepared as a substrate sheet. The obtained adhesive was applied to one surface of the substrate sheet so that the thickness of the dried adhesive layer became 12 μm, and dried at 100 ℃ for two minutes to form an adhesive layer. A release sheet (Super Stik) SP-PET38 manufactured by Lintec) having a thickness of 38 μm was attached to the adhesive layer to obtain an adhesive sheet. After one week of curing at 23-50% RH, various evaluations were performed.

(examples 2 to 57 and comparative examples 1 and 2)

Urethane adhesives and adhesive sheets using the same were produced in the same manner as in example 1, except that the formulation composition of the adhesives was changed as shown in tables 5 and 7 in examples 2 to 57 and comparative examples 1 and 2. In each of the examples in tables 5 and 7, conditions not shown in the tables are common conditions.

[ evaluation items and evaluation methods of adhesive sheet ]

The evaluation items and evaluation methods of the adhesive sheet are as follows.

(substrate adhesion)

The adhesive layer of the obtained adhesive sheet was half-cut 11 times at 1mm intervals in two mutually orthogonal linear directions to form 100 cells in a 1mm square. After the 100-cell whole was rubbed with a finger back and forth 20 times, the number of remaining cells on the substrate sheet was visually counted. The evaluation criteria are as follows.

Very good: the number of remaining cells is preferably 71 to 100.

O: the number of remaining cells was 51 to 70, which was good.

And (delta): the number of remaining cells is 21 to 50, and this is practical.

X: the number of remaining cells is 0 to 20, and this is not practical.

(initial hardenability)

The release sheet is peeled from the obtained adhesive sheet. The exposed surface of the adhesive layer was rubbed with a fingertip, and the presence or absence of a trace of rubbing of the components having no adhesive layer on the fingertip and the surface of the adhesive layer was visually observed. The evaluation criteria are as follows.

Very good: the adhesive layer is excellent in that no component adheres to the fingertip, and no mark after rubbing remains on the surface of the adhesive layer.

O: the components of the adhesive layer were not attached to the finger tip, but traces of the adhesive layer after rubbing remained slightly, which was good.

And (delta): the adhesive layer is formed by adhering a plurality of components of the adhesive layer to a fingertip, and is sticky, and a trace after friction slightly remains on the surface of the adhesive layer, and thus the adhesive layer is practical.

X: the adhesive layer is clearly adhered to the finger tip, and the finger tip has a sticky feeling, and a mark after friction remains on the surface of the adhesive layer, which is not practical.

(scratch resistance)

The release sheet is peeled from the obtained adhesive sheet. The tip (pen tip) of a POM pen (pen tip diameter 0.8mm) inclined at an angle of 45 ° with respect to the exposed surface of the adhesive layer was brought into contact with the surface of the adhesive layer. The pen tip was moved horizontally by about 10cm so as to draw a straight line while maintaining the above state. The same operation was performed at a total of 10 sites by changing the position. The number of damaged portions was determined by visually observing the damage of each portion. The visual observation was carried out under a fluorescent lamp. The evaluation criteria are as follows.

Very good: no damage and high quality.

O: one to two sites had lesions, good.

And (delta): the three to five parts have damages, which is practical.

X: more than six parts are damaged, and the utility model is not practical.

(curved surface Tight-contact Property)

From the adhesive sheet thus obtained, a test piece having a width of 25mm and a length of 40mm was cut out. Then, the release sheet was peeled from the test piece in an atmosphere of 23 to 50% RH, and the exposed adhesive layer was attached along the peripheral surface of a cylindrical body (diameter: 30 mm. phi., height: 300mm) made of polypropylene. At this time, the width direction of the test piece and the height direction of the cylinder are combined. After the sample was left to stand in an environment of 23 to 50% RH for three days, the adhesion degree of the test piece to the cylinder was visually observed. The evaluation criteria are as follows.

O: the end of the test piece did not float and was good.

And (delta): the test piece has a floating end, and the width of the peeled portion is 1mm or more but less than 3mm, and is practical.

X: the end of the test piece was floated, and the width of the peeled portion was 3mm or more, which was not practical.

(Re-peelability (60 ℃ -90% RH, 24 hours))

From the adhesive sheet thus obtained, a test piece having a width of 25mm and a length of 100mm was cut out. Subsequently, the release sheet was peeled from the test piece in an environment of 23 to 50% RH, the exposed adhesive layer was attached to a caustic soda glass plate, and the pressure-bonding was performed by reciprocating a 2kg roller once from the test piece. Then, the mixture was left in an atmosphere of 60 to 90% RH for 24 hours and air-cooled in an atmosphere of 23 to 50% RH for 30 minutes. Then, the adhesion was measured under the conditions of a peeling speed of 300mm/min and a peeling angle of 180 ℃ using a tensile tester (Tencilon, manufactured by Orientec Co., Ltd.) in accordance with JIS Z0237. And easily peeled off again when the adhesive force is low. The evaluation criteria are as follows.

Very good: less than 50mN/25mm, and excellent.

O: it is preferably 50mN/25mm or more and less than 100mN/25 mm.

And (delta): more than 100mN/25mm and 300mN/25mm, and is practical.

X: more than 300mN/25mm, it is not practical.

(folding endurance)

From the adhesive sheet thus obtained, a test piece having a width of 25mm and a length of 40mm was cut out. Then, the release sheet was peeled from the test piece at 60 ℃ to adhere about half of the exposed adhesive layer in the longitudinal direction to a10 mm thick caustic soda glass plate, and the rest was folded back in the 180 ° direction to adhere. The mixture was left at 60 ℃ for three days. Then, the degree of adhesion to the caustic soda glass plate was visually observed at the bent portion and the end portion of the portion to which the test piece was attached. The evaluation criteria are as follows.

Very good: the bent portions and the end portions are free from floating and excellent.

O: the bent portion and/or the end portion is/are raised, and the width of the peeled portion is preferably less than 1 mm.

And (delta): the bent part and/or the end part are/is floated, and the width of the peeled part is more than 1mm and less than 3mm, so that the utility model can be realized.

X: the bent portion and/or the end portion are/is floated, and the width of the peeled portion is 3mm or more, which is not practical.

(tailorability)

A100 mm square test piece was cut out from the obtained adhesive sheet. As a punching machine, an SA1008 small punch type III (manufactured by TESTER sankyo) was prepared. Punching was continuously performed 50 times with a circular thomson blade having a diameter of 10mm, and the cuttability was evaluated. The evaluation criteria are as follows.

Very good: the adhesive component is not adhered to the blade, so that the release sheet can be cleanly released from the punched circular adhesive sheet with a light force, and the cutting tool is excellent.

O: the adhesive component slightly adheres to the blade, but the release sheet can be cleanly released from the punched circular adhesive sheet with a light force, which is good.

And (delta): the adhesive component is slightly adhered to the blade, or the release sheet is slightly resistant to peeling from the punched circular adhesive sheet, and therefore, the adhesive sheet is practically usable.

X: the adhesive component is clearly adhered to the blade, or the resistance when the release sheet is peeled from the punched circular adhesive sheet is large, and therefore, the method is not practical.

(Heat resistance (150 ℃ C., 1 hour))

From the adhesive sheet thus obtained, a test piece having a width of 25mm and a length of 100mm was cut out. Subsequently, the release sheet was peeled from the test piece in an environment of 23 to 50% RH, the exposed adhesive layer was attached to a caustic soda glass plate, and the pressure-bonding was performed by reciprocating a 2kg roller once from the test piece. Then, the mixture was left at 150 ℃ for 1 hour and air-cooled at 23 to 50% RH for 30 minutes. Then, the adhesion was measured under the conditions of a peeling speed of 300mm/min and a peeling angle of 180 ℃ using a tensile tester (Tencilon, manufactured by Orientec Co., Ltd.) in accordance with JIS Z0237. And easily peeled off again when the adhesive force is low. The evaluation criteria are as follows.

Very good: less than 500mN/25mm, and is excellent.

O: 500mN/25mm or more and less than 1000mN/25mm, good.

And (delta): 1000mN/25mm or more and 3000mN/25mm, and is practical.

X: more than 3000mN/25mm, it is not practical.

[ evaluation results ]

The evaluation results are shown in tables 6 and 8.

In Synthesis examples 1 to 36, hydroxyl-terminated urethane prepolymers (UPH-1) to (UPH-36) having a branching degree α of 0.2 to 0.8 were obtained by using a polyisocyanate (N) and at least one active hydrogen group-containing compound (H) containing an active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less and/or an active hydrogen group-containing compound (HY) having a branching degree α of more than 0.5.

In examples 1 to 57 using the hydroxyl-terminated urethane prepolymer (UPH-1) to hydroxyl-terminated urethane prepolymer (UPH-36) having a branching degree α of 0.2 to 0.8, the obtained pressure-sensitive adhesive sheet was excellent in the evaluation results of initial curability and removability (60 to 90% RH). The evaluation results were also good for other evaluation items.

In synthesis examples 1 to 13, 16 and 17, the one or more active hydrogen group-containing compounds (H) contain 50 mass% or more of an active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less, and the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree α of 0.2 to 0.6. The pressure-sensitive adhesive sheets obtained in examples 1 to 22, 25 and 26 using the hydroxyl-terminated Urethane Prepolymer (UPH) obtained in these synthesis examples were excellent in initial curing properties and removability (effect of suppressing increase in adhesive force) when exposed to a hot environment, particularly a moist-heat environment, and further excellent in substrate adhesiveness, scratch resistance and curved surface adhesiveness.

In synthesis examples 19 to 29, 31, 33, and 36, the one or more active hydrogen group-containing compounds (H) contained 50 mass% or more of an active hydrogen group-containing compound (HY) having a branching degree α of more than 0.5, and the hydroxyl-terminated Urethane Prepolymer (UPH) had a branching degree α of more than 0.6 and 0.8 or less. The adhesive sheets obtained in examples 28 to 46, 48, 50 and 53 using the hydroxyl-terminated Urethane Prepolymer (UPH) obtained in these synthesis examples were excellent in initial curing properties and removability (effect of suppressing increase in adhesive force) when exposed to a thermal environment, particularly a moist thermal environment, and further excellent in folding resistance, cuttability and heat resistance.

In Synthesis example 41, a hydroxyl-terminated urethane prepolymer (UPC-1) for comparison having a branching degree α of less than 0.2 was obtained by using an active hydrogen group-containing compound (HX) having a branching degree α of 0.5 or less and a polyisocyanate (N).

In Synthesis example 42, using an active hydrogen group-containing compound (HY) exceeding 0.5 and a polyisocyanate (N), a hydroxyl-terminated urethane prepolymer for comparison (UPC-2) having a branching degree α exceeding 0.8 was obtained.

In comparative examples 1 and 2 using the hydroxyl-terminated urethane prepolymer for comparison (UPC-1) or the hydroxyl-terminated urethane prepolymer for comparison (UPC-2), the adhesive sheets obtained were poor in the results of evaluation of initial curability and removability (60 ℃ to 90% RH). The evaluation results were also poor for many other evaluation items.

[ Table 5]

[ Table 6]

[ Table 7]

[ Table 8]

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

This application claims priority based on Japanese patent application No. 2020-112855, filed on 30/6/2020, the entire disclosure of which is incorporated herein by reference.

[ description of symbols ]

10. 20: adhesive sheet

11. 21: substrate sheet

12. 22A, 22B: adhesive layer

13. 23A, 23B: release sheet

Claims

1. An adhesive, comprising:

a polyfunctional isocyanate compound (I) in which, in the adhesive,

the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree of 0.2 to 0.8 as measured by a gel permeation chromatography-multi-angle laser light scattering method.

2. The adhesive according to claim 1, wherein the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HX) having a branching degree of 0.5 or less as measured by a gel permeation chromatography-multi-angle laser light scattering method,

the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree of 0.2 to 0.6 as measured by a gel permeation chromatography-multi-angle laser light scattering method.

3. The adhesive according to claim 2, wherein the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HX-S) having a branching degree of 0.3 or less as measured by a gel permeation chromatography-multi-angle laser light scattering method.

4. The adhesive according to claim 2, wherein the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more and less than 100% by mass of an active hydrogen group-containing compound (HX) having a branching degree of 0.5 or less as measured by a gel permeation chromatography-multi-angle laser light scattering method, and contain more than 0% by mass and less than 50% by mass of an active hydrogen group-containing compound (HY) having a branching degree of more than 0.5 as measured by a gel permeation chromatography-multi-angle laser light scattering method.

5. The adhesive according to claim 1, wherein the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HY) having a branching degree of more than 0.5 as measured by gel permeation chromatography-multi-angle laser light scattering,

the hydroxyl-terminated Urethane Prepolymer (UPH) has a branching degree of more than 0.6 and 0.8 or less as measured by a gel permeation chromatography-multi-angle laser light scattering method.

6. The adhesive according to claim 5, wherein the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more of an active hydrogen group-containing compound (HY-L) having a branching degree of more than 0.6 as measured by gel permeation chromatography-multi-angle laser light scattering method.

7. The adhesive according to claim 5, wherein the one or more active hydrogen group-containing compounds (H) contain 50% by mass or more and less than 100% by mass of an active hydrogen group-containing compound (HY) having a branching degree of more than 0.5 as measured by a gel permeation chromatography-multi-angle laser light scattering method, and contain more than 0% by mass and less than 50% by mass of an active hydrogen group-containing compound (HX) having a branching degree of 0.5 or less as measured by a gel permeation chromatography-multi-angle laser light scattering method.

8. The adhesive of any one of claims 1 to 7, further comprising a plasticizer.

9. The adhesive according to any one of claims 1 to 8, further comprising an antistatic agent.

10. The adhesive according to any one of claims 1 to 9, further comprising one or more deterioration preventing agents selected from the group consisting of an antioxidant, a hydrolysis resistance agent, an ultraviolet absorber, and a light stabilizer.

11. An adhesive sheet comprising a substrate sheet and an adhesive layer containing a cured product of the adhesive according to any one of claims 1 to 10.