KR20210143867A - Hydroxyl-terminated urethane prepolymer-containing solution and manufacturing method thereof, pressure-sensitive adhesive and pressure-sensitive adhesive sheet and manufacturing method thereof - Google Patents

Abstract

The present invention provides a solution containing a hydroxyl-terminated urethane prepolymer for an adhesive having a reduced amount of organic solvent used, a relatively high solid content concentration, and a relatively low viscosity. Provided is an adhesive having a reduced amount of organic solvent used, a relatively high solids concentration, and a relatively low viscosity at the time of application so as to have good coating aptitude. The hydroxyl-terminated urethane prepolymer-containing solution for an adhesive of the present invention is a hydroxyl-terminated urethane which is a reaction product of at least one active hydrogen group-containing compound (HX) having a plurality of active hydrogen groups in one molecule and at least one polyisocyanate (N). A prepolymer (UPH) is included, solid content concentration is 80 mass % or more, and the viscosity in 25 degreeC after leaving still at 25 degreeC immediately after preparation is 8000 mPa*s or less. The pressure-sensitive adhesive of the present invention contains the hydroxyl-terminated urethane prepolymer-containing solution of the present invention and the polyfunctional isocyanate compound (I).

Description

Hydroxyl-terminated urethane prepolymer-containing solution and manufacturing method thereof, pressure-sensitive adhesive and pressure-sensitive adhesive sheet and manufacturing method thereof

The present invention relates to a solution containing a hydroxyl-terminated urethane prepolymer for an adhesive, a manufacturing method thereof, an adhesive, and an adhesive sheet and a manufacturing method thereof.

DESCRIPTION OF RELATED ART Conventionally, the adhesive sheet in which the adhesive layer was formed on the base material sheet is widely used as a surface protection sheet of various members. Examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive. Although the acrylic pressure-sensitive adhesive has excellent adhesive strength, re-peelability after adhering to an adherend is not good because of its strong adhesive strength. In particular, after time has elapsed in a high-temperature, high-humidity environment, the re-peelability is further lowered due to an increase in adhesive force, and there is a tendency to easily cause contamination of the adherend in which the adhesive remains on the surface of the adherend after re-peelling. Silicone pressure-sensitive adhesives tend to cause contamination on adherends, and silicone resins having a relatively low molecular weight may volatilize and adsorb to the surface of devices such as electronic devices, which may cause problems. On the other hand, the urethane-based pressure-sensitive adhesive has good adhesion to an adherend, and has relatively excellent re-peelability and is difficult to volatilize.

In the present specification, "adhesive" is a pressure-sensitive adhesive having re-peelability (re-peelable pressure-sensitive adhesive), and "adhesive sheet" is a pressure-sensitive adhesive sheet having re-peelability (re-peelable pressure-sensitive adhesive sheet).

Flat panel displays, such as liquid crystal displays (LCDs) and organic electroluminescent displays (OELDs), and touch panel displays combining such flat panel displays and touch panels, televisions (TVs), personal computers (PCs) ), is widely used in electronic devices such as mobile phones and portable information terminals.

The urethane-based pressure-sensitive adhesive sheet is a flat panel display and a touch panel display, and a substrate manufactured or used in their manufacturing process (a glass substrate and an ITO/glass substrate having an ITO (indium tin oxide) film formed on the glass substrate, etc.) and an optical member It is preferably used as a surface protection sheet, such as.

As a method for producing a urethane-based pressure-sensitive adhesive, a method using a hydroxyl-terminated urethane prepolymer and a polyfunctional isocyanate compound, which are reaction products of an active hydrogen group-containing compound such as polyol and polyisocyanate, and a polyol and polyfunctional isocyanate without using a hydroxyl-terminated urethane prepolymer There is a method in which the compounds are reacted at once (one-shot method).

A general method for producing a pressure-sensitive adhesive sheet includes a coating step of coating the pressure-sensitive adhesive on a base sheet, a heating step of heat-drying the formed coating layer to form a pressure-sensitive adhesive layer containing a cured product of the pressure-sensitive adhesive, and winding the obtained pressure-sensitive adhesive sheet.芯), the winding process made into the form of an adhesive sheet roll, and the curing process of curing an adhesive sheet roll are included.

Japanese Patent Publication No. 5194801 Japanese Patent Publication No. 6270818 Japanese Patent Publication No. 5466366 Japanese Patent Publication No. 6070633

Urethane-based pressure-sensitive adhesives are cured immediately after manufacturing, but if the initial curability is too high, the pot life is shortened, and the viscosity of the pressure-sensitive adhesive becomes too high until the pressure-sensitive adhesive is coated on the base sheet. There is a risk that it may become impossible. When the initial curability of the urethane-based pressure-sensitive adhesive is too low, the coating layer or the pressure-sensitive adhesive layer is affected by the mechanical stress received during winding and curing of the pressure-sensitive adhesive sheet obtained after heating and drying the hot air or heat drying of the coated layer, and the pressure-sensitive adhesive layer There is a risk of surface appearance defects such as step marks on the winding core, orange peel, and curls that occur when folded and placed. It is preferable that a urethane-type adhesive has favorable initial stage curability while having a favorable pot life.

In general, urethane-based pressure-sensitive adhesives contain an organic solvent, thereby adjusting to a relatively low viscosity suitable for coating. However, the use of volatile organic compounds (VOCs) is not preferable from an environmental point of view and the like, and the amount of the volatile organic compounds (VOCs) is preferably small. In the conventional urethane-based pressure-sensitive adhesive, when the amount of the organic solvent is reduced, the viscosity of the pressure-sensitive adhesive increases. There exists a tendency for coatability to fall.

It is preferable that a urethane-based pressure-sensitive adhesive having a relatively low viscosity suitable for coating can be provided even if the amount of the organic solvent is reduced and the solid content concentration is increased. Conventionally, although the solid content concentration of a urethane type adhesive is less than 70 mass % in general, from a viewpoint of VOC reduction, Preferably it is 70 mass % or more, More preferably, it is 80 mass % or more.

Patent Documents 1 to 4 are mentioned as related documents of the present invention.

In patent document 1,

Preparation of a urethane resin in which a polyol and a polyisocyanate compound are reacted in an excess ratio of isocyanate groups to obtain an isocyanate group-terminated prepolymer, then a chain extender is reacted with this isocyanate group-terminated prepolymer, and further, if necessary, a terminal terminator is reacted As a method,

The chain extender includes a polyfunctional compound (X) having three or more functional groups capable of reacting with an isocyanate group, two of the functional groups of the polyfunctional compound (X) are primary hydroxyl groups, and the remaining functional groups are secondary hydroxyl groups or tertiary groups is a hydroxyl group,

The polyfunctional compound (X) is at least one selected from the group consisting of a compound represented by the formula (1) and a compound represented by the formula (2), a method for producing a urethane resin for a pressure-sensitive adhesive is disclosed (claim 1).

Patent Document 1 discloses an adhesive containing a urethane resin obtained by the above-mentioned manufacturing method (claim 5).

Patent Document 1 discloses a method for producing a hydroxyl-terminated urethane prepolymer-containing solution by two-step polymerization and a urethane-based pressure-sensitive adhesive comprising the hydroxyl-terminated urethane prepolymer-containing solution.

Patent Document 1 describes, "In the pressure-sensitive adhesive of the present invention, since the urethane resin is not gelled, it is not necessary to lower the solid content concentration in order to lower the viscosity.” (Paragraph 0055). However, the polyurethane solutions obtained in Examples 1 to 8 had a low solid content concentration of 47 to 50% by mass (Table 1), and a viscosity at 24° C. as low as 3700 to 5100 mPa·s (Table 1), and this poly The adhesive using a urethane solution is estimated to have low solid content concentration, and it cannot be said that the VOC reduction effect is sufficient. That is, Patent Document 1 does not specifically mention a solution containing a hydroxyl-terminated urethane prepolymer having a high solid content concentration and an adhesive having a high solid content concentration containing the same.

In patent document 2,

(A) an active hydrogen compound having an average molecular weight of 1.2×10 ⁴ or more and an average functional group number of 3;

(B) an active hydrogen compound having an average molecular weight of 0.1 × 10 ⁴ or more and an average number of functional groups of 2;

(C) an organic polyisocyanate having an average functional group number of 2

A solvent-free polyurethane pressure-sensitive adhesive obtained by reacting is disclosed (claim 1).

In Patent Document 2, "The polyurethane-based adhesive of the present invention obtained by combining the active hydrogen compound (A) and the active hydrogen compound (B) has moderate cohesive force, and is preferable at the point of becoming a polymer having a flexible structure. In the polyurethane pressure-sensitive adhesive obtained in this way, the mixture has a suitable viscosity at the time of coating, which is advantageous also in terms of coatability. ' (paragraph 0019).

However, the urethane-type adhesive of patent document 2 is a urethane-type adhesive by a one-shot method. In general, an adhesive layer using a urethane-based adhesive obtained by a one-shot method is hard, and the surface smoothness of the adhesive layer tends to deteriorate due to curing shrinkage. Since diluents, such as a solvent and a plasticizer, are not especially contained in the urethane-type adhesive of patent document 2, coatability cannot be said to be good, but said tendency is remarkable. The viscosity of the urethane-type adhesive of patent document 2 is unclear.

Patent Document 3 discloses (A) a urethane prepolymer containing terminal isocyanate groups obtained by reacting a polyol with an excess of a polyisocyanate compound, (B) a fine powder coated amine, and (C) a tackifier. A liquid solvent-free urethane-based pressure-sensitive adhesive composition is disclosed (Claim 1).

In patent document 3, "it is a solvent-free type adhesive composition which does not contain a solvent substantially. Therefore, in the case of manufacturing an adhesive from the pressure-sensitive adhesive composition of the present invention, it is possible to prevent environmental pollution due to odors or volatile organic compounds (VOCs).” (Paragraph 0025). However, since the urethane-type adhesive of patent document 3 does not contain diluents, such as a solvent and a plasticizer, coatability is not good. The viscosity of the urethane-type adhesive of patent document 3 is unclear.

In Patent Document 4, 100 parts by weight of a polyurethane resin (A) having a primary hydroxyl group at the terminal and having a hydroxyl value of 10 to 40 mgKOH/g, 1 to 20 parts by weight of a polyfunctional isocyanate compound (B), and polyalkylene glycol A releasable urethane-based pressure-sensitive adhesive composition containing 25 to 100 parts by weight of at least one (C) selected from a compound, an epoxy compound, and a phosphate ester compound is disclosed (Claim 1).

In Synthesis Examples 1 to 5 and Examples 1 to 18 of Patent Document 4, a polyurethane resin solution having a nonvolatile content of 60% by mass and a urethane pressure-sensitive adhesive containing the same are manufactured.

The solid content concentration of the polyurethane resin solution obtained in Synthesis Examples 1 to 5 is a conventional general level, and the urethane-based pressure-sensitive adhesive described in Examples 1 to 18 including it has a solid content concentration at a conventional general level, and the VOC reduction effect is not sufficient. , the viscosity is also unclear.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solution containing a hydroxyl-terminated urethane prepolymer for an adhesive having a reduced amount of organic solvent used, a relatively high solid content concentration, and a relatively low viscosity.

Another object of the present invention is to provide a pressure-sensitive adhesive having a relatively low viscosity at the time of application so as to reduce the amount of organic solvent used, to have a relatively high solid content, and to have good coating ability.

The hydroxyl-terminated urethane prepolymer-containing solution for the pressure-sensitive adhesive of the present invention,

It comprises a hydroxyl-terminated urethane prepolymer (UPH) which is a reaction product of at least one active hydrogen group-containing compound (HX) having a plurality of active hydrogen groups in one molecule and at least one polyisocyanate (N),

Solid content concentration is 80 mass % or more, and the viscosity in 25 degreeC after leaving still at 25 degreeC immediately after preparation is 8000 mPa*s or less.

In the solution containing the hydroxyl-terminated urethane prepolymer for the pressure-sensitive adhesive of the present invention,

The at least one active hydrogen group-containing compound (HX) is preferably at least one polyol (HA) having a number average molecular weight of 1000 or more, and at least one active hydrogen group having a plurality of active hydrogen groups in one molecule having a number average molecular weight of less than 1000. hydrogen group-containing compound (HB).

The adhesive of this invention contains the hydroxyl-terminal urethane prepolymer containing solution of said this invention, and polyfunctional isocyanate compound (I).

Preferably, the adhesive of this invention has a solid content concentration of 80 mass % or more, and the viscosity in 25 degreeC after leaving still at 25 degreeC immediately after preparation is 5000 mPa*s or less.

The adhesive sheet of this invention contains the adhesive layer which consists of a base material sheet and the hardened|cured material of the said adhesive of this invention.

According to the present invention, it is possible to provide a solution containing a hydroxyl-terminated urethane prepolymer for an adhesive having a reduced amount of the organic solvent used, a relatively high solid content concentration, and a relatively low viscosity.

According to the present invention, it is also possible to provide a pressure-sensitive adhesive having a relatively low viscosity at the time of application so as to reduce the amount of the organic solvent used, to have a relatively high solid content, and to have good coating ability.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the adhesive sheet of 1st Embodiment which concerns on this invention,
It is a schematic cross section of the adhesive sheet of 2nd Embodiment which concerns on this invention.

The hydroxyl-terminated urethane prepolymer-containing solution for the pressure-sensitive adhesive of the present invention,

and a hydroxyl-terminated urethane prepolymer (UPH) which is a reaction product of at least one active hydrogen group-containing compound (HX) having a plurality of active hydrogen groups in one molecule and at least one polyisocyanate (N).

The pressure-sensitive adhesive of the present invention is a urethane-based pressure-sensitive adhesive comprising the hydroxyl-terminated urethane prepolymer-containing solution of the present invention and the polyfunctional isocyanate compound (I).

The pressure-sensitive adhesive sheet of the present invention is a urethane pressure-sensitive adhesive sheet comprising a base sheet and an adhesive layer composed of a cured product of the pressure-sensitive adhesive of the present invention.

The solution containing hydroxyl-terminated urethane prepolymer for adhesives of this invention reduces the usage-amount of an organic solvent, and has a comparatively high solid content concentration, and has a comparatively low viscosity. By using this hydroxyl-terminated urethane prepolymer-containing solution, the amount of the organic solvent used is reduced, the solid content concentration is relatively high, and the urethane-based pressure-sensitive adhesive of the present invention having a relatively low viscosity at the time of application to have good coating ability can be provided. . The pressure-sensitive adhesive of the present invention has a small amount of volatile organic compound (VOC), which is preferable from an environmental point of view.

The hydroxyl-terminal urethane prepolymer containing solution for adhesives of this invention is 80 mass % or more in solid content concentration, and the viscosity at 25 degreeC after leaving still at 25 degreeC immediately after preparation is 8000 mPa*s or less.

Solid content concentration of the adhesive of this invention becomes like this. Preferably it is 70 mass % or more, More preferably, it is 80 mass % or more, Especially preferably, it is 90 mass % or more. The viscosity in 25 degreeC of the adhesive of this invention after leaving still at 25 degreeC for 3 hours immediately after preparation becomes like this. Preferably it is 8000 mPa*s or less, More preferably, it is 7000 mPa*s or less, Especially preferably, it is 5000 mPa*s or less.

Although the preferable viscosity range differs with the coating method, the one with a low viscosity tends to be excellent in coatability. Although the viscosity of the adhesive of this invention changes with time from immediately after preparation, "the viscosity at 25 degreeC after standing still at 25 degreeC from immediately after preparation" assumes "the viscosity at the time of coating".

In this specification, unless otherwise specified, "solid content concentration" and "viscosity" shall be obtained by the method described in the item of [Example].

[adhesive]

(Solution containing hydroxyl-terminated urethane prepolymer)

The hydroxyl-terminated urethane prepolymer-containing solution of the present invention is a hydroxyl-terminated urethane prepolymer obtained by copolymerizing at least one active hydrogen group-containing compound (HX) having a plurality of active hydrogen groups in one molecule and at least one polyisocyanate (N). (UPH) solution. The copolymerization reaction may be carried out in the presence of one or more catalysts, if necessary. One or more types of solvents can be used for a copolymerization reaction as needed.

In order to realize a high solid content concentration and low viscosity of the pressure-sensitive adhesive, the hydroxyl-terminated urethane prepolymer (UPH) preferably has a lower molecular weight than the conventional hydroxyl-terminated urethane prepolymer. The weight average molecular weight (Mw) of the hydroxyl-terminated urethane prepolymer (UPH) is preferably 10000 to 10000, more preferably 13000 to 80000. Mw becomes like this. Preferably it is 60000 or less, More preferably, it is 15000-60000, Especially preferably, it is 10000-60000.

In this specification, "Mw" is a polystyrene conversion weight average molecular weight calculated|required by gel permeation chromatography (GPC) measurement. "Mn" is a polystyrene conversion number average molecular weight calculated|required by GPC measurement. These can be measured by the method described in the item of [Example].

The hydroxyl-terminated urethane prepolymer-containing solution of the present invention has a solid content concentration of 80% by mass or more, preferably 85% by mass or more, more preferably 90% by mass or more, particularly preferably 95% by mass or more, from the viewpoint of reducing VOC of the adhesive. mass % or more.

The hydroxyl-terminated urethane prepolymer-containing solution of the present invention has a viscosity of 8000 mPa·s or less at 25° C. immediately after preparation from the viewpoint of pot life and coatability of the pressure-sensitive adhesive and after standing at 25° C. for 1 hour, preferably 7000 mPa·s Hereinafter, more preferably, it is 6000 mPa*s or less, Especially preferably, it is 5000 mPa*s or less.

At least one active hydrogen group-containing compound (HX), which is a raw material of hydroxyl-terminated urethane prepolymer (UPH), has a number average molecular weight of 1000 at least one polyol (HA) (a relatively high molecular weight component) of at least one It is preferable to do

That is, as a hydroxyl-terminated urethane prepolymer (UPH), Mn is 1000 or more types of polyols (HA), Mn is less than 1000 types of active hydrogen group containing compounds (HB) containing multiple types of active hydrogen group containing compounds A hydroxyl-terminated urethane prepolymer (UPH-S), which is a reaction product of (HX) and at least one polyisocyanate (N), is preferred.

From the viewpoint of pot life and initial curability, at least one active hydrogen group-containing compound (HX), which is a raw material of hydroxyl-terminated urethane prepolymer (UPH), contains an active hydrogen group containing a primary hydroxyl group having a suitable reactivity as an active hydrogen group It is preferred to include a compound. In particular, it is preferable that at least one active hydrogen group-containing compound (HB) contains a primary hydroxyl group having appropriate reactivity as an active hydrogen group.

By adjusting the mass ratio of at least one polyol (HA), which is a relatively high molecular weight component, and at least one polyisocyanate (N), the weight average molecular weight (Mw) of the hydroxyl-terminated urethane prepolymer (UPH) is relatively small, and the high solid content of the pressure-sensitive adhesive Concentration and low viscosity can be realized. In general, a relatively low molecular weight hydroxyl-terminated urethane prepolymer (UPH) tends to have poor initial curability, so as one of the hydroxyl-terminated urethane prepolymer (UPH) raw materials, a relatively low molecular weight active hydrogen group-containing compound (HB) is used. By using it, initial hardenability can be improved.

In addition to the above-mentioned effects, by using a relatively high molecular weight polyol (HA) as one of the hydroxyl-terminated urethane prepolymer (UPH) raw materials, an effect of improving the wettability of the adhesive layer can be obtained.

Lowering the viscosity of the pressure-sensitive adhesive and improving the wettability of the pressure-sensitive adhesive layer can also be realized by adding a plasticizer (P) to the pressure-sensitive adhesive. When a plasticizer (P) is used, a solution containing a hydroxyl-terminated urethane prepolymer containing the plasticizer (P) may be prepared, and an adhesive may be prepared using this, and a solution containing a hydroxyl-terminated urethane prepolymer that does not contain the plasticizer (P) can also be prepared, and an adhesive can also be manufactured using this and a plasticizer (P). Since it is easy to realize both high solids and low viscosity of the hydroxyl-terminated urethane prepolymer-containing solution, it is preferable to prepare a hydroxyl-terminated urethane prepolymer-containing solution containing a plasticizer (P), and use it to prepare an adhesive.

In addition, by using a relatively low molecular weight active hydrogen group-containing compound (HB) as one of the hydroxyl-terminated urethane prepolymer (UPH) raw materials, the effect of improving the re-peelability of the adhesive layer can be obtained.

<Polyol (HA)>

The number average molecular weight (Mn) of the polyol (HA), which is a relatively high molecular weight component, is 1000 or more, preferably 1000 to 7000, more preferably 2000 to 6000, particularly preferably 3000 to 5000. When Mn is 1000 or more, the cohesive force of a hydroxyl-terminated urethane prepolymer (UPH) becomes preferable, and the initial stage curability of an adhesive and the wettability of an adhesive layer become favorable. When Mn is 7000 or less, the molecular weight of a hydroxyl-terminal urethane prepolymer (UPH) becomes preferable, and the pot life of an adhesive becomes favorable.

The type of polyol (HA) is not particularly limited, and examples thereof include polyester polyol, polyether polyol, polyacryl polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol. Among them, polyester polyols, polyether polyols, and combinations thereof are preferred. It is more preferable that one or more types of polyols (HA) contain polyether polyol which has moderate cohesive force from a viewpoint of wettability of an adhesive layer.

A well-known thing can be used as a polyester polyol, The compound (esterified product) obtained by the esterification reaction of 1 or more types of polyol components and 1 or more types of acid components is mentioned.

As the polyol component of the raw material, 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, glycerin, trimethylolpropane, pentaerythritol , and hexanetriol.

As the acid component of the raw material, succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanoic 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, 4,4'-biphenyldicarboxylic acid, and these of acid anhydride, etc. are mentioned.

A known polyether polyol can be used, and a compound (addition polymer) obtained by addition polymerization of one or more oxirane compounds using an active hydrogen group-containing compound having two or more active hydrogen groups in one molecule as an initiator is mentioned. can

As an initiator, a hydroxyl-containing compound, an amine, etc. are mentioned. Specifically, bifunctional initiators such as ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethylpentanediol, N-aminoethylethanolamine, isophoronediamine, and xylenediamine ; trifunctional initiators such as glycerin, trimethylolpropane, and triethanolamine; tetrafunctional initiators such as pentaerythritol, ethylenediamine, and aromatic diamine; 5 functional initiators, such as diethylenetriamine, etc. are mentioned.

Examples of the oxirane compound include alkylene oxides (AO) such as ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO); Tetrahydrofuran (THF), etc. are mentioned.

As the polyether polyol, an alkylene oxide adduct (also referred to as "polyoxyalkylene polyol") of an active hydrogen group-containing compound is preferable. Among them, bifunctional polyether polyols such as polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene glycol; Trifunctional polyether polyols, such as an alkylene oxide adduct of glycerol, etc. are preferable.

<Active hydrogen group-containing compound (HB)>

The number average molecular weight (Mn) of the active hydrogen group-containing compound (HB), which is a relatively low molecular weight component, is less than 1000, preferably 50 to 900, more preferably 50 to 300, particularly more preferably 50 to 200. As described above, in general, a relatively low-molecular-weight hydroxyl-terminated urethane prepolymer (UPH) tends to have poor initial curability. By using the containing compound (HB), initial curability can be improved.

Examples of the active hydrogen group include a hydroxyl group, a mercapto group, and an amino group (in this specification, unless otherwise specified, an amino group includes an imino group). Examples of the active hydrogen group-containing compound (HB) include a polyol having a plurality of hydroxyl groups in one molecule, a polyamine having a plurality of amino groups in one molecule, an amino alcohol having an amino group and a hydroxyl group in one molecule, and a plurality of mercapto groups in one molecule. polythiol which has, etc. are mentioned. These can be used 1 type or 2 or more types. The active hydrogen group-containing compound (HB) may be either a non-polymer or a polymer.

Among them, polyols are preferable. Since polyamines and polythiols have high reactivity and short pot life, when using them, it is preferable to use them together with polyols. In addition, when the polyol contains a secondary hydroxyl group, since the initial curability of the urethane-based pressure-sensitive adhesive is not improved, from the viewpoint of pot life and initial curability, the active hydrogen group-containing compound (HB) is an active hydrogen group having a suitable reactivity. It is preferable that a primary hydroxyl group is included, and it is more preferable that only primary hydroxyl group is included as an active hydrogen group.

Examples of the non-polymer polyol include ethylene glycol (EG), propylene glycol (PG), diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 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 (also referred to as “1,3-octanediol”), 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol , 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane (TMP), pentaerythritol, and hexanetriol.

Examples of the polymer polyol that can be used as the active hydrogen group-containing compound (HB) include polyester polyol, polyether polyol, polyacrylic polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol. Among them, polyester polyols, polyether polyols, and combinations thereof are preferred.

Examples of polyester polyols and polyether polyols are the same as those given for polyols (HA).

Examples of the polyamine that can be used as the active hydrogen group-containing compound (HB) include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6 -Hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1, 16-hexadecanediamine, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, methyliminobispropylamine, 1,5-diamino-2-methylpentane, isophoronediamine, 1,3-bisaminomethylcyclo Hexane, 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3,3,5-trimethyl-cyclohexylamine, norborneine skeleton dimethyleneamine, metaxylenediamine (MXDA), hexamethylenediaminecar aliphatic polyamines such as barmate, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 3,3'-diamino Diphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, 3,3'-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 aromatic polyamines such as diethyltoluenediamine; and the like.

Examples of the amino alcohol that can be used as the active hydrogen group-containing compound (HB) include monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tri(hydroxymethyl)aminomethane, and 2-amino- monoamines having a hydroxyl group such as 2-ethyl-1,3-propanediol; diamines having a hydroxyl group such as N-(2-hydroxypropyl)ethanolamine; and the like.

Examples of the polythiol that can be used as the active hydrogen group-containing compound (HB) include methanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, and 1,2-benzenedithiol. ol, 1,3-benzenedithiol, 1,4-benzenedithiol, 1,10-decanedithiol, 1,2-ethanedithiol, 1,6-hexanedithiol, 1,9-nonanedithiol, 1,8-octane dithiol, 1,5-pentanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, toluene-3,4-dithiol, 3,6-dichloro-1,2 -Benzene dithiol, 1,5-naphthalenedithiol, 1,2-benzene dimanethiol, 1,3-benzene dimanethiol, 1,4-benzene dimanethiol, 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, a thiol group terminal polymer (polysulfide polymer etc.), etc. are mentioned.

The number of functional groups (number of hydroxyl groups) of one or more types of polyols (HA) is arbitrary, and multiple types of polyols (HA) from which the number of functional groups differ can also be used together as needed. Similarly, the number of functional groups (the number of active hydrogen groups) of at least one active hydrogen group-containing compound (HB) is arbitrary, and a plurality of active hydrogen group-containing compounds (HB) having different functional groups may be used in combination as needed.

The at least one polyol (HA) may include a bifunctional polyol and/or a trifunctional or higher polyol. Likewise, the at least one active hydrogen group-containing compound (HB) may include a bifunctional 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 pressure-sensitive adhesive layer. The trifunctional or more active hydrogen group-containing compound has three-dimensional crosslinking and can impart appropriate hardness to the pressure-sensitive adhesive layer. According to the selection of the number of functional groups (the number of active hydrogen groups) of at least one polyol (HA) and at least one active hydrogen group-containing compound (HB), the properties such as adhesion, cohesion, and re-peelability of the urethane-based pressure-sensitive adhesive Can be adjusted. Depending on the use and the like, the number of functional groups of each material can be selected so that properties such as adhesive force, cohesive force, and re-peelability are within a preferable range.

Since it is easy to make adhesive force and re-peelability compatible, it is preferable that the 1 or more types of polyols (HA) contains a trifunctional or more than trifunctional polyol, It is preferable that it contains trifunctional or more than trifunctional polyether polyol. Since it is easy to make reaction stability and cohesion force compatible, it is preferable that at least 1 type of active hydrogen group containing compound (HB) contains a bifunctional active hydrogen group containing compound.

A plurality of active hydrogen group-containing compounds (HX), which are raw materials for hydroxyl-terminated urethane prepolymers (UPH), contain at least one known active hydrogen group-containing compound other than the above polyol (HA) and active hydrogen group-containing compound (HB). may contain

<Polyisocyanate (N)>

As polyisocyanate (N), a well-known thing can be used, An aromatic polyisocyanate, an aliphatic polyisocyanate, an alicyclic polyisocyanate, etc. are mentioned.

Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4′,4″-triphenylmethanetriisocyanate, ω,ω′-diisocyanate-1,3-dimethylbenzene, ω,ω′-diisocyanate-1,4-dimethylbenzene, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylenediisocyanate, 1,3-tetramethylxylylenediisocyanate, etc. are mentioned.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, and 1,3-butylene diisocyanate. isocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate, etc. are mentioned.

Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexanediisocyanate, and methyl-2,4-cyclohexanedi. isocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis(cyclohexylisocyanate), and 1,4-bis(isocyanatemethyl)cyclohexane.

Other examples of the polyisocyanate include a trimethylolpropane adduct, biuret, allophanate, and trimer of the polyisocyanate (this trimer includes an isocyanurate ring) .) and the like.

As polyisocyanate (N), 4,4'- diphenylmethane diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), etc. are preferable. Although the details will be described later, the at least one polyisocyanate (N) preferably contains isophorone diisocyanate (IPDI).

The preferable raw material mixing ratio of a hydroxyl-terminated urethane prepolymer (UPH) is as follows.

The ratio (NCO/H) of the number of moles of the isocyanate group (NCO) of the polyisocyanate (N) to the total number of moles of the active hydrogen groups (H) of the plurality of active hydrogen group-containing compounds (HX) is 0.20 to 0.84, It is preferable to determine the raw material compounding ratio so that it may become more preferably 0.40-0.80. As NCO/H approaches 1, it tends to become easier to gel at the time of synthesizing a hydroxyl-terminated urethane prepolymer (UPH). When NCO/H is 0.84 or less, gelation at the time of synthesizing a hydroxyl-terminated urethane prepolymer (UPH) can be effectively suppressed.

The amount of the at least one active hydrogen group-containing compound (HB) with respect to 100 parts by mass of the at least one polyol (HA) from the viewpoint of improving the initial curability of the pressure-sensitive adhesive while implementing a high solid content concentration and low viscosity of the pressure-sensitive adhesive, Preferably it is 0.5-40 mass parts, More preferably, it is 2-40 mass parts, Especially preferably, it is 1-25 mass parts.

The amount of the at least one polyisocyanate (N) with respect to 100 parts by mass of the at least one polyol (HA) is preferably It is 1-50 mass parts, More preferably, it is 3-30 mass parts.

<Catalyst>

For polymerization of the hydroxyl-terminated urethane prepolymer (UPH), one or more catalysts may be used as needed. A well-known thing can be used as a catalyst, A tertiary amine type compound, an organometallic compound, etc. are mentioned.

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

Examples of the organometallic compound include a tin-based compound and a non-tin-based compound.

Examples of the tin-based compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, Tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin dilaurate, dioctyltin oxide, tributyltin chloride, tributyltin trichloro loacetate, and 2-ethyl tin hexanoate.

Examples of the non-tin-based compound include titanium-based compounds such as dibutyl titanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead systems such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron systems such as iron 2-ethylhexanoate and iron acetylacetate; cobalt type such as cobalt benzoate and cobalt 2-ethylhexanoate; Zinc types, such as zinc naphthenate and zinc 2-ethylhexanoate; Zirconium systems, such as zirconium naphthenate, are mentioned.

The kind and addition amount of the catalyst can be appropriately designed within the range in which the reaction proceeds favorably.

When a plurality of active hydrogen group-containing compounds (HX) are used simultaneously, gelation or cloudiness of the reaction solution may easily occur in a single catalyst system due to differences in the reactivity of each active hydrogen group-containing compound (HX). . In this case, by using two types of catalysts, it becomes easy to control reaction (for example, reaction rate, etc.), and the said problem can be solved. The combination of the two types of catalysts is not particularly limited, and examples thereof include tertiary amine/organometallic, tin/non-tin, and tin/tin. Preferred are tin-based/tin-based, more preferably dibutyltin dilaurate and tin 2-ethylhexanoate.

The mass ratio of tin 2-ethylhexanoate to dibutyltin dilaurate (tin 2-ethylhexanoate/dibutyltin dilaurate) is not particularly limited, and is preferably more than 0 and less than 1, more preferably 0.2 ~0.6. When the mass ratio is less than 1, the catalyst activity is well balanced, gelation and cloudiness of the reaction solution are effectively suppressed, and polymerization stability is further improved.

<solvent>

One or more solvents can be used for polymerization of the hydroxyl-terminated urethane prepolymer (UPH) as needed. As a solvent, a well-known thing can be used, In general, organic solvents, such as methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone, are used.

Since the hydroxyl-terminated urethane prepolymer containing solution of this invention can have a low viscosity even at high solid content concentration, the usage-amount of the organic solvent can be reduced. Content of the organic solvent in the hydroxyl-terminal urethane prepolymer containing solution of this invention becomes like this. Preferably it is 20 mass % or less, More preferably, it is 10 mass % or less, and 0 mass % may be sufficient. The hydroxyl-terminated urethane prepolymer-containing solution of the present invention is preferable from an environmental point of view because the amount of volatile organic compounds (VOCs) used is small.

<Method for producing a solution containing hydroxyl-terminated urethane prepolymer>

The hydroxyl-terminated urethane prepolymer-containing solution is, if necessary, in the presence of one or more solvents, using one or more catalysts as necessary, and at least one active hydrogen group-containing compound (HX) and at least one polyisocyanate (N) It can be prepared by copolymerization reaction. It does not restrict|limit especially as a polymerization method, Well-known polymerization methods, such as a block polymerization method and a solution polymerization method, are applicable. The polymerization reaction can be carried out in one step or in multiple steps.

Reaction temperature in the case of using a catalyst becomes like this. Preferably it is less than 100 degreeC, More preferably, it is 50-95 degreeC, Especially preferably, it is 60-85 degreeC. When the reaction temperature is 100° C. or higher, it becomes difficult to control the reaction rate and polymerization stability, and there is a fear that it becomes difficult to produce a hydroxyl-terminated urethane prepolymer (UPH) having a desired molecular weight. Reaction temperature in the case of not using a catalyst becomes like this. Preferably it is 100 degreeC or more, More preferably, it is 110 degreeC or more.

Hereinafter, a plurality of types comprising at least one polyol (HA) having an Mn of 1000 or more, preferably 1000 to 7000, and at least one active hydrogen group-containing compound (HB) having an Mn of less than 1000, preferably 50 to 900 A preferred method for producing a hydroxyl-terminated urethane prepolymer (UPH-S), which is a reaction product of an active hydrogen group-containing compound (HX) and at least one polyisocyanate (N), will be described.

As the polymerization procedure of the hydroxyl-terminated urethane prepolymer (UPH-S),

Procedure 1) at least one polyol (HA), at least one active hydrogen group-containing compound (HB), at least one polyisocyanate (N), optionally at least one catalyst, and optionally at least one solvent the order of input into the flask;

Step 2) At least one polyol (HA), at least one active hydrogen group-containing compound (HB), at least one catalyst as required, and at least one solvent as required are added to a flask, and at least one solvent is added thereto. The procedure of adding polyisocyanate (N) dropwise;

Step 3) At least one polyol (HA), at least one polyisocyanate (N), at least one catalyst if necessary, and at least one solvent as necessary are put into the flask at once, and at least one polyol ( HA) by reacting at least one polyisocyanate (N) in an excess ratio of isocyanate groups to produce an isocyanate group-terminated urethane prepolymer (UPN-S), and then adding at least one active hydrogen group-containing compound (HB) sequence; and the like.

In Step 1) and Step 2), a relatively high molecular weight polyol (HA) and a relatively low molecular weight active hydrogen group-containing compound (HB) are simultaneously mixed with the polyisocyanate (N). In this method, a relatively low molecular weight active hydrogen group-containing compound (HB) with high reactivity tends to react preferentially with polyisocyanate (N) rather than a relatively high molecular weight polyol (HA) with low reactivity. In this case, a relatively high molecular weight polyol (HA) having low reactivity may remain unreacted and the reaction solution may become cloudy. In order to eliminate the relatively high molecular weight polyol (HA) remaining unreacted, when the number of moles of isocyanate groups is excessive with respect to the total number of moles of active hydrogen groups, a relatively low molecular weight active hydrogen group-containing compound (HB) There is a risk that an undesired reaction between an isocyanate group-terminated urethane prepolymer produced by first reacting with a polyisocyanate (N) and a relatively low molecular weight active hydrogen group-containing compound (HB) with high reactivity occurs, resulting in gelation of the reaction solution .

Since the reaction is easy to control, step 3) is preferable. The polymerization according to this procedure is a step of reacting at least one polyol (HA) and at least one polyisocyanate (N) in an excess ratio of isocyanate groups to produce an isocyanate group-terminated urethane prepolymer (UPN); and reacting a urethane prepolymer (UPN) with at least one active hydrogen group-containing compound (HB).

In step 3), only a relatively high molecular weight polyol (HA) having a low reactivity is first reacted with a polyisocyanate (N) in a state in which a relatively low molecular weight active hydrogen group-containing compound (HB) does not coexist, and then the obtained isocyanate A group-terminated urethane prepolymer (UPN) and an active hydrogen group-containing compound (HB) are reacted. In this method, gelation and cloudiness of the reaction solution can be suppressed, and a desired hydroxyl-terminated urethane prepolymer (UPH-S) can be stably synthesized.

Therefore, the hydroxyl-terminated urethane prepolymer (UPH-S) is a reaction product of an isocyanate-terminated urethane prepolymer (UPN), which is a reaction product of a polyol (HA) and a polyisocyanate (N), and an active hydrogen group-containing compound (HB). it is preferable

In step 3), it is preferable that the at least one polyisocyanate (N) contains isophorone diisocyanate (IPDI). In this case, the reaction is easy to control, and a desired hydroxyl-terminated urethane prepolymer (UPH-S) can be stably synthesized.

(Polyfunctional isocyanate compound (I))

A well-known thing can be used as polyfunctional isocyanate compound (I), The compound illustrated as polyisocyanate (N) which is a raw material of a hydroxyl-terminated urethane prepolymer (UPH) (specifically, an aromatic polyisocyanate, an aliphatic polyisocyanate, an aromatic aliphatic poly isocyanate, alicyclic polyisocyanate, and their trimethylolpropane adduct/biuret/allophanate/trimer) can be used.

(plasticizer (P))

The pressure-sensitive adhesive of the present invention may include one or more plasticizers (P), if necessary. The plasticizer (P) may function as a diluent together with the solvent. By adding the plasticizer (P) to the pressure-sensitive adhesive of the present invention, it is preferable to realize a low viscosity even at a high solid content concentration. When the pressure-sensitive adhesive of the present invention contains a plasticizer (P), the pressure-sensitive adhesive layer has good wettability to an adherend such as glass, and when the pressure-sensitive adhesive sheet is attached to the adherend, it suppresses the entrainment of air bubbles at the adhesion interface. effect can be obtained.

The quantity of the plasticizer (P) with respect to 100 mass parts of hydroxyl-terminal urethane prepolymer (UPH) becomes like this. Preferably it is 0-200 mass parts, More preferably, it is 20-200 mass parts. The amount of the plasticizer (P) with respect to 100 parts by mass of the hydroxyl terminal urethane prepolymer (UPH) is particularly preferably 50 to 200 parts by mass or 20 to 150 parts by mass, and most preferably 50 to 150 parts by mass.

It does not restrict|limit especially as a plasticizer (P), From a viewpoint of compatibility with other components, etc., the organic acid ester of molecular weight 250-1,000 is preferable.

Esters of monobasic or polybasic acids and alcohols include, for example, isostearyl laurate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isostearyl palmitate, and isocetyl stearate. , octyldodecyl oleate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, diisodecyl adipate, diisostearyl adipate, dibutyl sebacate, diisocetyl sebacate, Tributyl acetyl citrate, tributyl trimellitate, trioctyl trimellitate, trihexyl trimellitate, trioleyl trimellitate, and triisocetyl trimellitate etc. are mentioned.

As esters of other acids and alcohols, for example, unsaturated fatty acids or branched acids such as myristic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, and isostearic acid, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, penta Ester with alcohol, such as erythritol and sorbitan, is mentioned.

Examples of esters of monobasic acid or polybasic acid and polyalkylene glycol include polyethylene glycol dihexylate, polyethylene glycol di-2-ethylhexyl acid, polyethylene glycol dilauryl acid, polyethylene glycol dioleate, and dipolyethylene adipic acid. Glycol methyl ether etc. are mentioned.

From a viewpoint of wettability improvement etc., the molecular weight (formula or Mn) of organic acid ester becomes like this. Preferably it is 250-1,000, More preferably, it is 400-900, Especially preferably, it is 500-850. When molecular weight is 250 or more, the heat resistance of an adhesion layer becomes favorable. The wettability of an adhesive becomes favorable that molecular weight is 1,000 or less, and an adhesive can be effectively reduced in viscosity.

(β-diketone compound (X))

The pressure-sensitive adhesive of the present invention may contain at least one β-diketone compound (X), if necessary. The β-diketone compound (X) is not particularly limited, and acetylacetone, 2,4-pentanedione, 3-methyl-2,4-pentanedione, 2,4-hexanedione, 1,3-cyclohexanedione, 2,2-dimethyl-3,5-hexanedione, 2,4-heptanedione, 3,5-heptanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 1,3-cyclo Heptanedione, 2,4-octanedione, 2,2,7-trimethyl-3,5-octanedione, 2,4-nonanedione, 3-methyl-2,4-nonanedione, 2-methyl-4,6 -nonanedione, 1-phenyl-1,3-butanedione, spirodecanedione, etc. are mentioned. Especially, acetylacetone etc. are preferable. The beta -diketone compound (X), such as acetylacetone, functions as a curing retardant, and can adjust a pot life favorably by adding to an adhesive.

(solvent)

The pressure-sensitive adhesive of the present invention may contain one or more solvents as needed. A well-known thing can be used as a solvent, Organic solvents, such as methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone, are mentioned.

Since the adhesive of this invention has a comparatively high solid content concentration and has a comparatively low viscosity at the time of coating so that it may have favorable coating aptitude, the usage-amount of the organic solvent can be reduced.

Content of the organic solvent in the adhesive of this invention becomes like this. Preferably it is 20 mass % or less, More preferably, it is 10 mass % or less, and 0 mass % may be sufficient. The pressure-sensitive adhesive of the present invention has a small amount of volatile organic compound (VOC), which is preferable from an environmental point of view.

(discoloration inhibitor)

The pressure-sensitive adhesive of the present invention may include one or more anti-change agents, if necessary. Accordingly, it is possible to suppress deterioration of various properties due to long-term use of the adhesive layer. Examples of the deterioration inhibitor include a hydrolysis-resistant agent, an antioxidant, an ultraviolet absorber, and a light stabilizer.

<Hydrolysis resistant agent>

When a carboxyl group is generated due to a hydrolysis reaction in the adhesive layer under a high-temperature, high-humidity environment, etc., a hydrolysis-resistant agent may be used to block the carboxyl group. Examples of the hydrolysis-resistant agent include carbodiimide-based, isocyanate-based, oxazoline-based, and epoxy-based agents. In particular, the carbodiimide type is preferable from the viewpoint of the hydrolysis inhibitory effect.

A carbodiimide-based hydrolysis inhibitor 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 Naphthyl carbodiimide etc. are mentioned.

The polycarbodiimide compound can be produced by subjecting diisocyanate to a decarboxylation condensation reaction in the presence of a carbodiimidization catalyst. Here, as the diisocyanate, for example, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4 '-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolyl Rendiisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, etc. are mentioned. Examples of the carbodiimidization catalyst include 1-phenyl-2-phosphorene-1-oxide, 3-methyl-2-phosphorene-1-oxide, 1-ethyl-3-methyl-2-phosphorene-1-oxide; phosphorene oxides such as 1-ethyl-2-phosphoene-1-oxide and 3-phosphoene isomers thereof; and the like.

As the isocyanate-based hydrolysis inhibitor, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4 '-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6 - Hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylene diisocyanate, tetramethylxylylene diisocyanate, hydrogen Added xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate etc. are mentioned. have.

Examples of the oxazoline-based hydrolysis inhibitor include 2,2'-o-phenylenebis(2-oxazoline), 2,2'-m-phenylenebis(2-oxazoline), 2,2' -p-phenylenebis(2-oxazoline), 2,2'-p-phenylenebis(4-methyl-2-oxazoline), 2,2'-m-phenylenebis(4-methyl-2 -oxazoline), 2,2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4,4'-dimethyl-2-oxa) zoline), 2,2'-ethylenebis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline), 2,2 '-octamethylenebis(2-oxazoline), 2,2'-ethylenebis(4-methyl-2-oxazoline), and 2,2'-diphenylenebis(2-oxazoline). have.

Examples of the epoxy-based hydrolysis inhibitor include diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, and polyalkylene glycol; polyglycidyl ethers of aliphatic polyols 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 polyhydric carboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid; Resorcinol, bis-(p-hydroxyphenyl)methane, 2,2-bis-(p-hydroxyphenyl)propane, tris-(p-hydroxyphenyl)methane, and 1,1,2,2- diglycidyl ether or polyglycidyl ether of polyhydric phenols such as tetrakis(p-hydroxyphenyl)ethane; N of amines such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, and N,N,N',N'-tetraglycidyl-bis-(p-aminophenyl)methane -glycidyl derivatives; triglycidyl derivatives of aminophenols; Epoxy resins, such as triglycidyl tris (2-hydroxyethyl) isocyanurate and triglycidyl isocyanurate; Orthocresol type|mold epoxy resin, and a phenol novolak type|mold epoxy resin, etc. are mentioned.

The amount of the hydrolysis resistant agent added is not particularly limited, and with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH), preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4.5 parts by mass, particularly preferably 0.5 to 3 parts by mass. is the mass part.

<Antioxidant>

Examples of the antioxidant include a radical scavenger and a peroxide decomposing agent. As a radical scavenger, a phenol-type compound, an amine-type compound, etc. are mentioned. Examples of the peroxide decomposing agent include sulfur-based compounds and phosphoric acid-based compounds.

Examples of the phenolic compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearin-β-( 3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4- ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol) ), 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetra Oxaspiro [5,5] undecane, benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4-hydroxy-, C7-C9 branched alkyl ester, 1,1,3-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, bis[3,3'-bis-(4'-hydroxy -3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3'5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4, 6-(1H,3H,5H)trione, and tocopherol; and the like.

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

As the phosphorus compound, for example, triphenylphosphite, diphenylisodecylphosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenylditridecyl)phosphite, cyclic Neopentanetetraylbis(octadecylphosphite), tris(nonylphenyl)phosphite, tris(monononylphenyl)phosphite, tris(dinonylphenyl)phosphite, diisodecylpentaerythritol 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, tris(2,4-di-tert-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,4-di-tert-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,6-di-tert-butyl-4-methylphenyl)phosphite, and 2, 2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite etc. are mentioned.

By using the antioxidant, thermal deterioration of the hydroxyl-terminated urethane prepolymer (UPH) can be prevented. Moreover, the bleed-out of the plasticizer (P) from the adhesion layer in the case of using a plasticizer (P) can be suppressed effectively.

The amount of the antioxidant added is not particularly limited, and with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH), preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, particularly preferably 0.2 to 2 parts by mass. is wealth

As the antioxidant, from the viewpoint of stability and antioxidant effect, it is preferable to use at least one phenolic compound as a radical scavenger, and at least one phenolic compound as a radical scavenger and at least one phosphorus compound as a peroxide decomposing agent. more preferably. In addition, as the antioxidant, a phenol-based compound as a radical scavenger and a phosphorus compound as a peroxide decomposing agent are used in combination, and it is particularly preferable to use these antioxidants and the above-mentioned hydrolysis-resistant agent in combination.

<Ultraviolet absorbent>

Examples of the ultraviolet absorber include a benzophenone-based compound, a benzotriazole-based compound, a salicylic acid-based compound, an oxalic acid anilide-based compound, a cyanoacrylate-based compound, and a triazine-based compound.

The amount of the ultraviolet absorber added is not particularly limited, and with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH), preferably 0.01 to 3 parts by mass, more preferably 0.1 to 2.5 parts by mass, particularly preferably 0.2 to 2 parts by mass. is wealth

<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, and with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH), preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1.5 parts by mass, particularly preferably 0.2 to 1 parts by mass. is wealth

(Antistatic agent (AS-made))

The pressure-sensitive adhesive of the present invention may include at least one antistatic agent (AS agent), if necessary. Examples of the antistatic agent include inorganic salts, polyhydric alcohol compounds, ionic liquids, ionic solids, and surfactants, and among them, ionic liquids and/or ionic solids are preferable. In addition, "ionic liquid" is also called room temperature molten salt, and it is a salt with fluidity|liquidity at 25 degreeC.

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

Examples of the polyhydric alcohol compound include propanediol, butanediol, hexanediol, polyethylene glycol, trimethylolpropane, and pentaerythritol.

Examples of the ionic liquid containing imidazolium ions include 1-ethyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide, 1,3-dimethylimidazoliumbis(trifluoro methylsulfonyl)imide and 1-butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide.

Examples of the ionic liquid containing pyridinium ions include 1-methylpyridiniumbis(trifluoromethylsulfonyl)imide, 1-butylpyridiniumbis(trifluoromethylsulfonyl)imide, 1- Hexylpyridiniumbis(trifluoromethylsulfonyl)imide, 1-octylpyridiniumbis(trifluoromethylsulfonyl)imide, 1-hexyl-4-methylpyridiniumbis(trifluoromethylsulfonyl) ) imide, 1-hexyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-octyl-4-methylpyridinium bis ( Fluorosulfonyl)imide, 1-methylpyridiniumbis(perfluoroethylsulfonyl)imide, 1-methylpyridiniumbis(perfluorobutylsulfonyl)imide, etc. are mentioned.

Examples of the ionic liquid containing ammonium ions include trimethylheptylammonium bis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl-N-propylammoniumbis(trifluoromethanesulfonyl) Ponyl) imide, N,N-diethyl-N-methyl-N-pentylammoniumbis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl-N-heptylammoniumbis(tri Fluoromethanesulfonyl)imide, tri-n-butylmethylammonium bistrifluoromethanesulfonimide, etc. are mentioned.

In addition, commercially available ionic liquids, such as a pyrrolidinium salt, a phosphonium salt, and a sulfonium salt, can be used suitably.

An ionic solid is a salt of a cation and an anion like an ionic liquid, but it is a substance that exhibits the properties of a solid at 25°C under normal pressure. As a cation, an alkali metal ion, a phosphonium ion, a pyridinium ion, an ammonium ion, etc. are preferable, for example.

Examples of the ionic solid containing alkali metal ions include lithium bisfluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium bispentafluoroethylsulfonylimide, lithium bisheptafluoro Ropropylsulfonylimide, lithium bisnonanefluorobutylsulfonylimide, sodium bisfluorosulfonylimide, sodium bistrifluoromethylsulfonylimide, sodium bispentafluoroethylsulfonylimide, Sodium bisheptafluoropropylsulfonylimide, sodium bisnonanefluorobutylsulfonylimide, potassium bisfluorosulfonylimide, potassium bistrifluoromethylsulfonylimide, potassium bispentafluoroethylsulf Ponylimide, potassium bisheptafluoropropylsulfonylimide, potassium bisnonanefluorobutylsulfonylimide, etc. are mentioned.

Examples of the ionic solid containing phosphonium ions include tetrabutylphosphoniumbisfluorosulfonylimide, tetrabutylphosphoniumbistrifluoromethylsulfonylimide, tetrabutylphosphoniumbispentafluoroethyl Sulfonylimide, tetrabutylphosphoniumbisheptafluoropropylsulfonylimide, tetrabutylphosphoniumbisnonanefluorobutylsulfonylimide, tributylhexadecylphosphoniumbisfluorosulfonylimide, tributyl Hexadecylphosphoniumbistrifluoromethylsulfonylimide, tributylhexadecylphosphoniumbispentafluoroethylsulfonylimide, tributylhexadecylphosphoniumbisheptafluoropropylsulfonylimide, tributylhexadecyl Phosphoniumbisnonanefluorobutylsulfonylimide, tetraoctylphosphoniumbisfluorosulfonylimide, tetraoctylphosphoniumbistrifluoromethylsulfonylimide, tetraoctylphosphoniumbispentafluoroethylsulfonyl imide, tetraoctylphosphoniumbisheptafluoropropylsulfonylimide, and tetraoctylphosphoniumbisnonanefluorobutylsulfonylimide; and the like.

Examples of the ionic solid containing pyridinium ions include 1-hexadecyl-4-methylpyridiniumbisfluorosulfonylimide, 1-hexadecyl-4-methylpyridiniumbistrifluoromethylsulfonyl. Imid, 1-hexadecyl-4-methylpyridiniumbispentafluoroethylsulfonylimide, 1-hexadecyl-4-methylpyridiniumbisheptafluoropropylsulfonylimide, and 1-hexadecyl-4 -Methylpyridiniumbisnonanefluorobutylsulfonylimide etc. are mentioned.

Examples of the ionic solid containing ammonium ions include lauryl trimethylammonium chloride, tributylmethylbistrifluoromethylsulfonylimide, tributylmethylbispentafluoroethylsulfonylimide, and tributylmethylbis. Heptafluoropropylsulfonylimide, tributylmethylbisnonanefluorobutylsulfonylimide, octyltributylbistrifluoromethylsulfonylimide, octyltributylbispentafluoroethylsulfonylimide , octyltributylbisheptafluoropropylsulfonylimide, octyltributylbisnonanefluorobutylsulfonylimide, tetrabutylbisfluorosulfonylimide, tetrabutylbistrifluoromethylsulfonyl imide, tetrabutylbispentafluoroethylsulfonylimide, tetrabutylbisheptafluoropropylsulfonylimide, and tetrabutylbisnonanefluorobutylsulfonylimide; and the like.

In addition, a well-known ionic solid whose cation is a pyrrolidinium ion, an imidazolium ion, a sulfonium ion, etc. can be used suitably.

Surfactants are classified into low molecular weight surfactants and high molecular weight surfactants. In either type, there are nonionic, anionic, cationic, and amphoteric types.

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

Examples of the anionic low-molecular surfactant include alkylsulfonates, alkylbenzenesulfonates, and alkylphosphates.

Examples of the cationic low molecular surfactant include tetraalkylammonium salts and trialkylbenzylammonium salts.

Examples of the amphoteric low molecular surfactant include alkyl betaine and alkyl imidazolium betaine.

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

Polystyrene sulfonic acid type|mold etc. are mentioned as anionic polymer surfactant.

Examples of the cationic polymer surfactant include a quaternary ammonium salt-containing acrylate polymer type.

Examples of the amphoteric polymeric surfactant include amino acid-type amphoteric surfactants such as higher alkylaminopropionate, betaine-type amphoteric surfactants such as higher alkyldimethylbetaine and higher alkyldihydroxyethylbetaine.

To [ the addition amount of antistatic agent / 100 mass parts of hydroxyl-terminal urethane prepolymer (UPH)], Preferably it is 0.01-10 mass parts, More preferably, it is 0.03-5 mass parts.

(leveling agent)

The pressure-sensitive adhesive of the present invention may include a leveling agent, if necessary. By adding a leveling agent, the leveling property of an adhesion layer can be improved. As a leveling agent, an acryl-type leveling agent etc. are preferable from a viewpoint of suppressing the to-be-adhered body contamination after adhesive sheet re-peeling, which includes an acryl-type leveling agent, a fluorine-type leveling agent, and a silicone-type leveling agent.

The weight average molecular weight (Mw) of the leveling agent is not particularly limited, preferably 500 to 20,000, more preferably 1,000 to 15,000, particularly preferably 2,000 to 10,000. When Mw is 500 or more, the amount of vaporization from a coating layer at the time of heat-drying of a coating layer is small enough, and surrounding contamination is suppressed. When Mw is 20,000 or less, the leveling property improvement effect of an adhesion layer is expressed effectively.

The amount of the leveling agent to be added is not particularly limited, and from the viewpoint of suppressing contamination of the adherend after peeling the pressure-sensitive adhesive sheet and improving the leveling property of the pressure-sensitive adhesive layer, relative to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH), preferably 0.001 to 2 mass part, More preferably, it is 0.01-1.5 mass part, Especially preferably, it is 0.1-1 mass part.

(other optional ingredients)

The pressure-sensitive adhesive of the present invention may contain other optional components as needed within a range that does not impair the effects of the present invention. Examples of other optional components include catalysts, resins other than urethane-based resins, fillers (talc, calcium carbonate, titanium oxide, etc.), metal powder, colorants (pigments, etc.), foil-like materials, softeners, conductive agents, silane coupling agents, lubricants, and corrosion inhibitors. , a heat-resistant stabilizer, a weather-resistant stabilizer, a polymerization inhibitor, and an antifoaming agent.

(mixture ratio)

The pressure-sensitive adhesive of the present invention contains at least one hydroxyl group-terminated urethane prepolymer (UPH) and at least one polyfunctional isocyanate compound (I) as essential components, and also contains at least one optional component as necessary. Although these compounding ratios in particular are not restrict|limited, Preferred compounding ratios are as follows.

The amount of the at least one polyfunctional isocyanate compound (I) relative to 100 parts by mass of the at least one hydroxyl-terminated urethane prepolymer (UPH) is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass. If the quantity of 1 or more types of polyfunctional isocyanate compound (I) is 3 mass parts or more, the cohesive force of an adhesion layer will become favorable, and if it is 20 mass parts or less, a pot life will become favorable.

(Manufacturing method of adhesive)

The manufacturing method of the adhesive of this invention is not restrict|limited in particular.

With respect to the hydroxyl-terminated urethane prepolymer-containing solution synthesized by one-step or multiple-step copolymerization reaction, one or more polyfunctional isocyanate compounds (I) and, if necessary, one or more optional components are added and mixed to prepare the pressure-sensitive adhesive of the present invention can be manufactured.

[Adhesive sheet]

The pressure-sensitive adhesive sheet of the present invention includes a base sheet and an adhesive layer made of a cured product of the pressure-sensitive adhesive of the present invention. The adhesive layer may be formed on one or both surfaces of the base sheet. If necessary, the exposed surface of the pressure-sensitive adhesive layer may be covered with a release sheet. Further, the release sheet is peeled off when the pressure-sensitive adhesive sheet is adhered to the adherend.

A schematic cross-sectional view of the pressure-sensitive adhesive sheet of the first embodiment according to the present invention is shown in FIG. 1 . 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 in which an adhesive layer is formed on one surface of the base sheet.

The schematic cross section of the adhesive sheet of 2nd Embodiment which concerns on this invention in FIG. 2 is shown. In Fig. 2, reference numeral 20 denotes an adhesive sheet, reference numeral 21 denotes a base sheet, reference numerals 22A and 22B denote an adhesive layer, and reference numeral 23A and 23B denote a release sheet.

It does not restrict|limit especially as a base material sheet, A resin sheet, paper, metal foil, etc. are mentioned. The base sheet may be a laminated sheet in which any one or more layers are laminated on at least one side of these base sheets. If necessary, the surface of the base 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 application of an anchor coating agent.

It does not restrict|limit especially as structural resin of a resin sheet, Ester-type resins, such as a polyethylene terephthalate (PET); olefin resins such as polyethylene (PE) and polypropylene (PP); vinyl-based resins such as polyvinyl chloride; amide resins such as nylon 66; urethane-based resins (including foams); combinations thereof, and the like.

The thickness in particular of the resin sheet except a polyurethane sheet is not restrict|limited, Preferably it is 15-300 micrometers. The thickness of the polyurethane sheet (including foam) is not particularly limited, and is preferably 20 to 50,000 µm.

It does not restrict|limit especially as paper, Plain paper, coated paper, art paper, etc. are mentioned.

It does not restrict|limit especially as a structural metal of metal foil, Aluminum, copper, these combinations, etc. are mentioned.

It does not restrict|limit especially as a release sheet, A well-known release sheet in which the well-known peeling process, such as a release agent application|coating, was given to the surface of base material sheets, such as a resin sheet or paper, can be used.

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

First, the adhesive of this invention is coated on the surface of a base material sheet, and the coating layer which consists of adhesive of this invention is formed. As the coating method, a known method can be applied, and examples include a roll coater method, a comma coater method, a die coater method, a reverse coater method, a silk screen method, and a gravure coater method.

Next, the coating layer is dried and cured to form a pressure-sensitive adhesive layer made of a cured product of the pressure-sensitive adhesive of the present invention. Heat drying temperature in particular is not restrict|limited, About 60-150 degreeC is preferable. Although the thickness (thickness after drying) of an adhesion layer changes with a use, Preferably it is 0.1-200 micrometers.

Then, if necessary, a release sheet is affixed to the exposed surface of the pressure-sensitive adhesive layer by a known method.

As mentioned above, a single-sided adhesive sheet can be manufactured.

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

Contrary to the above method, the adhesive of the present invention is coated on the surface of a release sheet to form a coating layer made of the adhesive of the present invention, and then the coating layer is dried and cured to adhere to the cured product of the adhesive of the present invention After forming the layer, a base sheet may be laminated on the exposed surface of the pressure-sensitive adhesive layer.

The method for producing the pressure-sensitive adhesive sheet preferably includes a coating step of coating the pressure-sensitive adhesive on the base sheet, a heating step of heat-drying the formed coating layer to form a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive, and the obtained pressure-sensitive adhesive sheet. The winding process which winds around a core to make it into the form of an adhesive sheet roll, and the curing process of curing an adhesive sheet roll are included.

As described above, according to the present invention, it is possible to provide a solution containing a hydroxyl-terminated urethane prepolymer for a pressure-sensitive adhesive having a reduced amount of the organic solvent used, a relatively high solid content concentration, and a relatively low viscosity. According to the present invention, the solid content concentration is 80% by mass or more, preferably 85% by mass or more, particularly preferably 90% by mass or more, and most preferably 95% by mass or more. A solution containing a hydroxyl-terminated urethane prepolymer for an adhesive having a viscosity at 25° C. of 8000 mPa·s or less, preferably 7000 mPa·s or less, more preferably 6000 mPa·s or less, and particularly preferably 5000 mPa·s or less at 25° C. can be provided. have.

According to the present invention, it is possible to provide a pressure-sensitive adhesive having a relatively low viscosity at the time of application in which the amount of the organic solvent used is reduced, the solid content concentration is relatively high, and has good coating ability. According to the present invention, the solid content concentration is preferably 70% by mass or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more. A pressure-sensitive adhesive having a viscosity of preferably 8000 mPa·s or less, more preferably 7000 mPa·s or less, and particularly preferably 5000 mPa·s or less can be provided. Since the viscosity at 25 degreeC after leaving still at 25 degreeC from immediately after preparation is in the said range, favorable coating aptitude can be acquired.

In order to realize a high solid content concentration and low viscosity of the pressure-sensitive adhesive, the hydroxyl-terminated urethane prepolymer (UPH) used in the present invention preferably has a lower molecular weight than the conventional hydroxyl-terminated urethane prepolymer.

In order to achieve high solid content concentration and low viscosity of the pressure-sensitive adhesive and to improve initial curability of the pressure-sensitive adhesive, as a hydroxyl-terminated urethane prepolymer (UPH), Mn is 1000 or more, preferably 1000 to 7000, at least one polyol (HA) and a plurality of active hydrogen group-containing compounds (HX) including at least one active hydrogen group-containing compound (HB) having an Mn of less than 1000, preferably 50 to 900, and at least one polyisocyanate (N); A hydroxyl-terminated urethane prepolymer (UPH-S), which is a reaction product, is preferred.

By adjusting the mass ratio of at least one polyol (HA), which is a relatively high molecular weight component, and at least one polyisocyanate (N), the number average molecular weight (Mn) of the hydroxyl-terminated urethane prepolymer (UPH) is relatively small, and the high solid content of the pressure-sensitive adhesive Concentration and low viscosity can be realized. In general, a relatively low molecular weight hydroxyl-terminated urethane prepolymer (UPH) tends to have poor initial curability, so a relatively low molecular weight active hydrogen group-containing compound (HB) is used as one of the hydroxyl-terminated urethane prepolymer (UPH) raw materials. By doing so, initial hardenability can be improved. Moreover, preferably, by using the active hydrogen group containing compound (HB) containing the primary hydroxyl group which has moderate reactivity, pot life and initial stage curability can be made favorable.

If the pot life of an adhesive is favorable, uniform coating of an adhesive is possible, without the viscosity of an adhesive from becoming high too much until it coats an adhesive on a base material sheet. When the initial curability of the pressure-sensitive adhesive is good, the coating layer or the pressure-sensitive adhesive layer is not easily affected by the mechanical stress received during winding and curing of the pressure-sensitive adhesive sheet obtained after heat drying or hot air during heat drying of the coated layer, and It is suppressed from the occurrence of surface appearance defects such as winding core step marks, orange peel, and curls that occur when rolled up.

In addition to the above effects, by using a relatively high molecular weight polyol (HA) as one of the hydroxyl-terminated urethane prepolymer (UPH) raw materials, an effect of improving the wettability of the adhesive layer is obtained. In addition, by using a relatively low molecular weight active hydrogen group-containing compound (HB) as one of the hydroxyl-terminated urethane prepolymer (UPH) raw materials, the effect of improving the re-peelability of the adhesive layer is obtained.

When the wettability of an adhesive layer is favorable, when an adhesive sheet is adhere|attached to to-be-adhered bodies, such as glass, it will be suppressed that a bubble is drawn in to an adhesive interface. When the re-peelability of the pressure-sensitive adhesive layer is good, contamination of the adherend in which the pressure-sensitive adhesive component remains on the surface of the adherend after re-peeling of the pressure-sensitive adhesive sheet is effectively suppressed.

[purpose]

The adhesive sheet of the present invention may be used in the form of a tape, a label, a seal, and a double-sided tape. The pressure-sensitive adhesive sheet of the present invention is suitably used as a surface protection sheet, a cosmetic sheet, an anti-slip sheet, and the like.

Flat panel displays, such as liquid crystal displays (LCDs) and organic electroluminescent displays (OELDs), and touch panel displays combining such flat panel displays and touch panels are widely used in televisions (TVs), personal computers (PCs), mobile phones, and It is widely used in electronic devices, such as a portable information terminal.

The pressure-sensitive adhesive sheet of the present invention is a flat panel display and a touch panel display (collectively referred to as simply "display"), and a substrate manufactured or used in their manufacturing process (a glass substrate, and ITO (indium tin oxide) on a glass substrate ) Film-formed ITO/glass substrate etc.) and it is preferably used as surface protection sheets, such as an optical member.

Example

Hereinafter, manufacturing examples, examples according to the present invention, and comparative examples will be described. In addition, in the following description, unless otherwise specified, "part" means a mass part, "%" means mass %, and "RH" shall mean a relative humidity.

[Evaluation items and evaluation method]

The evaluation items and evaluation methods are as follows.

(Mn, Mw)

The number average molecular weight (Mn) and weight average molecular weight (Mw) of the urethane prepolymer were measured by gel permeation chromatography (GPC). The measurement conditions are as follows. In addition, both Mn and Mw are polystyrene conversion values.

<Measurement conditions>

Device: SHIMADZU Prominence (manufactured by Shimadzu Corporation),

column; Two TSKgelGMH made from TOSOH are connected in series,

Detector: Differential refractive index detector (RID-10A),

Solvent: tetrahydrofuran (THF),

Flow rate: 1mL/min,

Solvent temperature: 40℃,

Sample concentration: 0.1%,

Sample injection volume: 100μL.

(Viscosity at 25°C)

For measuring the viscosity at 25°C of the urethane prepolymer-containing solution, the polyol-containing solution, and the pressure-sensitive adhesive, the sample is placed in a glass bottle with a lid, the glass bottle is immersed in a constant temperature water bath at 25°C, and taken out after a predetermined time has elapsed, B It implemented using the type|mold viscometer ("TVB10 type|mold viscometer" made by the earthenware industry company).

The urethane prepolymer-containing solution and the polyol-containing solution were immediately put into a glass bottle with a lid after preparation and immersed in a constant temperature water bath at 25° C., and the viscosity was measured 1 hour later.

About the adhesive, after preparation, it was put into a glass bottle with a lid, and it was immersed in a constant temperature water bath at 25 degreeC, and measurement was performed 3 hours later. The viscosity after 3 hours from immediately after preparation assumes "the viscosity at the time of coating".

In addition, in the actual method for producing the pressure-sensitive adhesive sheet, the time from immediately after preparation of the pressure-sensitive adhesive to the application is not particularly limited, and from the viewpoint of desirability of the viscosity at the time of application of the pressure-sensitive adhesive, preferably within 6 hours, more preferably 3 within an hour

(solids concentration)

The solid content concentration of the urethane prepolymer-containing solution, the polyol-containing solution, and the pressure-sensitive adhesive was determined from the change in mass after drying with respect to before drying after heating and drying about 1 g of a sample at 120° C. for 20 minutes.

(VOC reduction effect of adhesive)

By measuring the solid content concentration of the pressure-sensitive adhesive by the above method, the VOC reduction effect of the pressure-sensitive adhesive was evaluated. It can be said that the usage-amount of an organic solvent is reduced, and the reduction effect of a volatile organic compound (VOC) is high, so that solid content concentration is high. The evaluation criteria are as follows.

(double-circle): Solid content concentration 90 mass % or more, excellent.

(circle): Solid content concentration 80 mass % or more and less than 90 mass %, good.

(triangle|delta): The solid content concentration is 70 mass % or more and less than 80 mass %, practical use.

×: Solid content concentration is less than 70% by mass, impractical.

(Port Life)

The pressure-sensitive adhesive immediately after preparation was placed in a glass bottle with a lid, and the glass bottle was immersed in a constant temperature water bath at 25°C, and the viscosity after 1 hour and 6 hours from the start of immersion was measured, respectively. The viscosity increase rate after 6 hours (viscosity after 6 hours/viscosity [times] after 1 hour) with respect to 1 hour was calculated. The evaluation criteria are as follows.

(double-circle): Viscosity increase rate is less than 200%, excellent.

○: A viscosity increase rate of 200% or more and less than 300%, good.

(triangle|delta): Viscosity increase rate 300% or more and less than 400%, practical use.

x: A viscosity increase rate is 400% or more, and it is impractical.

(Initial curing)

In Examples 1 to 54 and Comparative Examples 1 to 4, samples cured for 3 hours in an atmosphere of 23° C.-50% RH with respect to the pressure-sensitive adhesive sheet obtained by coating and drying the pressure-sensitive adhesive on the base sheet (3 hours) Curing adhesive sheet) and the sample (120-hour curing adhesive sheet) cured for 120 hours in the atmosphere of 23 degreeC-50%RH were provided.

For each sample, the gel fraction (mass %) was calculated as follows.

A test piece having a width of 30 mm and a length of 100 mm was cut out from the adhesive sheet after curing for a predetermined time, and this was affixed to a SUS mesh (eye size: 0.077 mm, wire diameter: 0.05 mm). This was immersed in ethyl acetate, extracted at 50° C. for 24 hours, and dried at 100° C. for 30 minutes to calculate the gel fraction (mass %) according to the following formula (1).

Gel fraction (mass %) = (G2/G1) x 100... (One)

In the above formula, each symbol represents the following parameters.

G1: the mass of the adhesive layer before extraction with ethyl acetate,

G2: The mass of the adhesive layer after extraction with ethyl acetate and drying.

In addition, according to the following formula (2), the gel fraction change rate between the 3-hour curing and the 120-hour curing was calculated.

Gel fraction change rate (%) = (H1/H2) × 100… (2)

In the above formula, each symbol represents the following parameters.

H1: Gel fraction of the adhesive layer of the adhesive sheet cured for 3 hours,

H2: Gel fraction of the adhesive layer of the adhesive sheet cured for 120 hours.

The evaluation criteria are as follows.

○: The gel fraction change rate is 70% or more, good.

(triangle|delta): The gel fraction change rate is 30% or more and less than 70%, practical use.

x: The gel fraction change rate is less than 30 %, and it is not practical.

(wettability)

In Examples 1 to 54 and Comparative Examples 1 to 4, after curing the pressure-sensitive adhesive sheet obtained by coating and drying the pressure-sensitive adhesive on the base sheet for 120 hours in an atmosphere of 23°C-50% RH, the width from the pressure-sensitive adhesive sheet A 50 mm length 100 mm test piece was cut out and left to stand for 30 minutes in an atmosphere of 23°C-50% RH, and then the release sheet was peeled from the test piece. At the end of the glass plate, one end in the longitudinal direction of the test piece from which the release sheet was peeled was fixed, and the other end, which was not fixed, was lifted by hand to a position of 5 cm in height from the surface of the glass plate. The hand was released in this state, and the time until the entire adhesive layer (length 100 mm) adhered to the surface of the glass plate was measured. The evaluation criteria are as follows.

(circle): Time until the whole adhesive layer closely_contact|adheres is less than 3 second, good.

(triangle|delta): The time until the whole adhesive layer closely_contact|adheres is 3 seconds or more and less than 6 seconds, practical use.

x: The time until the whole adhesive layer closely_contact|adheres is 6 second or more, and it is not practical.

(Re-peelability)

In Examples 1 to 54 and Comparative Examples 1 to 4, after curing the pressure-sensitive adhesive sheet obtained by coating and drying the pressure-sensitive adhesive on the base sheet for 120 hours in an atmosphere of 23°C-50% RH, the width from the pressure-sensitive adhesive sheet Two test pieces of 70 mm in length and 100 mm in length were cut out. For each of the two test pieces, the release sheet was peeled off under an atmosphere of 23°C-50% RH, and a caustic soda glass plate was adhered to the exposed surface of the adhesive layer, followed by compression with a laminator. The two obtained laminates were left to stand for 72 hours (condition 1) and 120 hours (condition 2), respectively, in the oven set to 60 degreeC-90%RH. After heating in an oven for a predetermined time, each of the two laminates was taken out and air-cooled under an atmosphere of 23°C-50% RH for 3 hours, and then the pressure-sensitive adhesive sheet was peeled from the glass plate, and re-peelability was evaluated by visual observation. . The evaluation criteria are as follows.

○: No adhesion of the adhesive layer component to the glass surface under all conditions, excellent.

Δ: In condition 1, there is no adhesion of the adhesive layer component to the glass surface, but in condition 2, adhesion of the adhesive layer component to the glass surface occurs, and practical use is possible.

x: Adhesion of the adhesive layer component to the glass surface occurs under all conditions, and it is not practical.

[ingredient]

The materials used are as follows.

<Polyol (HA) having a number average molecular weight (Mn) of 1000 or more>

(HA-1): Kuraray polyol P-1010 (abbreviation in the table: P-1010), manufactured by Kuraray Co., Ltd., bifunctional polyester polyol, Mn1000, number of hydroxyl groups 2, hydroxyl number 112;

(HA-2): Kuraray polyol F-3010 (abbreviation in the table: F-3010), manufactured by Kuraray Co., Ltd., trifunctional polyester polyol, Mn3000, number of hydroxyl groups 3 , hydroxyl value 56

(HA-3): PEG-1000, manufactured by Sanyo Chemical Co., Ltd., bifunctional polyether polyol (polyethylene glycol), Mn1000, number of hydroxyl groups 2, hydroxyl value 112,

(HA-4): Poly bd, manufactured by Idemitsu Co., Ltd., bifunctional polyolefin polyol, Mn2800, number of hydroxyl groups 2, hydroxyl value 40,

(HA-5): PP-2000, manufactured by Sanyo Kasei Co., Ltd., bifunctional polyether polyol, Mn2000, number of hydroxyl groups 2, hydroxyl value 56,

(HA-6): Exenol 5030 (abbreviation in the table: EXCE5030), manufactured by Asahi Glass Co., Ltd., trifunctional polyether polyol, Mn5100, 3 hydroxyl groups, 33 hydroxyl groups,

(HA-7): Exenol 851 (abbreviation in the table: EXCE851), manufactured by Asahi Glass Co., Ltd., trifunctional polyether polyol, Mn6700, 3 hydroxyl groups, 25 hydroxyl groups.

(HA-8): Preminol S4013F (abbreviation in the table: PREM S4013F), manufactured by Asahi Glass Co., Ltd., bifunctional polyether polyol, Mn12000, number of hydroxyl groups 2, hydroxyl number 9,

(HA-9): Preminol S3011 (abbreviation in the table: PREM S3011), manufactured by Asahi Glass Co., Ltd., trifunctional polyether polyol, Mn10000, 3 hydroxyl groups, 17 hydroxyl groups.

<The active hydrogen group-containing compound (HB) having a number average molecular weight (Mn) of less than 1000>

(HB-1): ethylene glycol (EG), including only primary hydroxyl,

(HB-2): 1,5-pentanediol, including only primary hydroxyl,

(HB-3): 2-ethyl-1,3-hexanediol (also called 1,3-octanediol), including primary and secondary hydroxyl groups,

(HB-4): PPG200 (numbers represent Mn, the same applies to PEG), polypropylene glycol, manufactured by Sanyo Kasei Corporation, contains only secondary hydroxyl;

(HB-5): PEG300, polyethylene glycol, manufactured by Sanyo Kasei, contains only primary hydroxyl;

(HB-6): PEG600, polyethylene glycol, manufactured by Sanyo Kasei, contains only primary hydroxyl;

(HB-7): glycerin, including primary and secondary hydroxyl groups,

(HB-8): trimethylolpropane (TMP), containing only primary hydroxyl,

(HB-9): 1-methylamino-2,3-propanediol (MAPD), manufactured by Tokyo Chemical Industry Co., Ltd., a polyol containing a trifunctional amino group, Mn105, a primary hydroxyl group, a secondary hydroxyl group, and an amino group.

<Polyisocyanate (N)>

(N-1): isophorone diisocyanate (IPDI), manufactured by Tokyo Kasei Co., Ltd.,

(N-2): hexamethylene diisocyanate (HDI), manufactured by Tokyo Chemical Industry Co., Ltd.,

(N-3): tolylene diisocyanate (a mixture of 2,4-tolylene diisocyanate (80 mass %) and 2,6-tolylene diisocyanate (20 mass %)) (TDI), the Tosoh Corporation make.

<Organic solvent (B)>

(B-1): Ethyl acetate, the Daicel company make.

<Plasticizer (P)>

(P-1): maleic acid ester plasticizer, DOM (dioctyl maleate), Daihachi Chemical Co., Ltd.;

(P-2): Orthophosphoric acid ester plasticizer, TOP (tris(2-ethylhexyl)phosphate), manufactured by Daihachi Chemical Co., Ltd.

(P-3): A polyether ester plasticizer, RS-700, the Adeka company make.

<Antioxidant (D)>

(D-1): IRGANOX 1135, manufactured by BASF.

<β-diketone compound (X) (curing retardant)>

(X-1): Acetylacetone, manufactured by Tokyo Chemical Industry Co., Ltd.

<Antistatic agent (AS-made) (F)>

(F-1): Erexel AS-804, made by Daiichi Kogyo Seiyaku.

<Polyfunctional isocyanate compound (I)>

(I-1): Sumidul N-3300, manufactured by Sumika Bayer Urethane, hexamethylene diisocyanate (HDI)/isocyanurate, solid content 100% by mass;

(I-2): Coronate HL, manufactured by Tosoh Corporation, hexamethylene diisocyanate (HDI)/trimethylolpropane (TMP) adduct, solid content 75% by mass;

(I-3): Desmodule Z4470BA, the Sumika Bayer Urethane company make, isophorone diisocyanate (IPDI)/isocyanurate, 70 mass % of solid content.

[Preparation of urethane prepolymer-containing solution or polyol-containing solution]

(Preparation Example 1) (Two-stage polymerization method)

100 parts by mass of polyol (HA-1), 40 parts by mass of polyisocyanate (N-1), and an organic solvent (B) as a diluent in a four-neck flask equipped with a stirrer, reflux cooling pipe, nitrogen inlet pipe, thermometer, and dropping funnel -1) 10 parts by mass, 100 parts by mass of a plasticizer (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were introduced and mixed. The temperature of the internal solution was gradually increased to 80°C, and reaction was performed for 2 hours to obtain an isocyanate group-terminated urethane prepolymer (reaction in the first stage). Next, the inner solution was cooled to 60°C, and 20 parts by mass of an active hydrogen group-containing compound (HB-2) was added, followed by mixing and reaction (reaction in the second stage).

In the entire reaction of the first and second stages, the total number of moles of active hydrogen groups (H) of all the active hydrogen group-containing compounds (HX) (in this example, (HA-1) and (HB-2)) used in the reaction Ratio (NCO/H) of the number of moles of the isocyanate group (NCO) which the polyisocyanate (N) used for the reaction with respect has was 0.62.

After confirming the disappearance of the remaining isocyanate groups by infrared spectroscopy (IR analysis), the solution was cooled and the reaction was terminated, and then 1 part by mass of antioxidant (D-1) and 3 parts by mass of β-diketone compound (X-1) parts were added and mixed.

As described above, a solution containing a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-1) was obtained.

Main manufacturing conditions and evaluation results are shown in Table 1-1 and Table 2-1.

Tables 1-1 to 1-7 show the raw material composition of the urethane prepolymer alone or the polyol mixture alone, NCO/H, and Mn and Mw of the urethane prepolymer.

Tables 2-1 to 2-2 show the composition of the urethane prepolymer-containing solution or polyol-containing solution, the solid content concentration, and the viscosity at 25°C immediately after preparation and after standing at 25°C for 1 hour.

The unit of the compounding quantity in a table|surface is "mass part" (it is the same also in another table|surface).

(Preparation Examples 2-40, 42-45) (two-stage polymerization method)

In the same manner as in Production Example 1 except for changing the type and blending ratio of the raw materials to be used, a solution containing hydroxyl-terminated urethane prepolymers (UPH-2) to (UPH-45) was obtained by a two-stage polymerization method.

100 parts by mass of one or more polyols (HA) or one or more polyols (HL), one or more polyisocyanates (N) in a four-neck flask equipped with a stirrer, reflux cooling tube, nitrogen introduction tube, thermometer, and dropping funnel , an organic solvent (B) and/or a plasticizer (P) as a diluent, and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were added and mixed. The temperature of the internal solution was gradually increased to 80°C, and reaction was performed for 2 hours to obtain an isocyanate group-terminated urethane prepolymer (reaction in the first stage). Then, the inner solution was cooled to 60°C, and at least one active hydrogen group-containing compound (HB) was added, mixed and reacted (reaction in the second stage).

After confirming the disappearance of the remaining isocyanate groups by infrared spectroscopy (IR analysis), the solution is cooled and the reaction is terminated, then an antioxidant (D-1) and a β-diketone compound (X-1) are added, and optionally AS agent (F-1) was further added and mixed. As described above, colorless and transparent hydroxyl-terminated urethane prepolymers (UPH-2) to (UPH-32) and (UPH-34) (UPH-37) containing solutions were obtained.

Main manufacturing conditions and evaluation results are shown in Table 1-1 - Table 1-6, and Table 2-1 - Table 2-2.

(Production Example 41) (Two-stage polymerization method)

In the same manner as in Production Example 1 except for changing the type and compounding ratio of the raw materials to be used, a two-stage polymerization method was used to obtain a solution containing a hydroxyl-terminated urethane prepolymer (UPH-33).

100 parts by mass of polyol (HB-6), 80 parts by mass of polyisocyanate (N-1), and an organic solvent (B) as a diluent in a four-necked flask equipped with a stirrer, reflux cooling pipe, nitrogen inlet pipe, thermometer, and dropping funnel -1) 10 parts by mass, 100 parts by mass of a plasticizer (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were added and mixed. An isocyanate group terminal urethane prepolymer was obtained by raising the temperature of an internal solution gradually to 80 degreeC, and performing reaction for 2 hours (1st stage reaction). Next, the inner solution was cooled to 60° C., an active hydrogen group-containing compound (HB-2) was added, and the mixture was mixed and reacted (reaction in the second stage).

After confirming the disappearance of the remaining isocyanate groups by infrared spectroscopy (IR analysis), the solution was cooled to terminate the reaction, and then an antioxidant (D-1) and a β-diketone compound (X-1) were added and mixed. . As described above, a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-41) containing solution was obtained.

The main production conditions and evaluation results are shown in Tables 1-6 and 2-2.

(Preparation Example 46) (Single-stage polymerization method)

100 parts by mass of polyol (HA-6), 8 parts by mass of active hydrogen group-containing compound (HB-2), organic as a diluent in a four-necked flask equipped with a stirrer, reflux cooling pipe, nitrogen inlet pipe, thermometer, and dropping funnel 10 parts by mass of a solvent (B-1), 100 parts by mass of a plasticizer (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were added and mixed, and the temperature of the inner solution was gradually increased to 80°C. Next, 13 mass parts of polyisocyanate (N-1) was added, and it was made to react for 2 hours. After confirming the disappearance of the remaining isocyanate groups by infrared spectroscopy (IR analysis), the solution was cooled and the reaction was terminated, and then 1 part by mass of antioxidant (D-1) and 3 parts by mass of β-diketone compound (X-1) parts were added and mixed. As described above, a solution containing a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-38) was obtained.

The main production conditions and evaluation results are shown in Tables 1-6 and 2-2.

(Preparation Examples 47 and 48) (single-stage polymerization method)

30 parts by mass of polyol (HA-1), 70 parts by mass of polyol (HA-7), and polyisocyanate (N-2) in a four-neck flask equipped with a stirrer, reflux cooling pipe, nitrogen inlet pipe, thermometer, and dropping funnel 5 parts by mass, 90 parts by mass or 30 parts by mass of an organic solvent (B-1) as a diluent, 40 parts by mass of a plasticizer (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were added and mixed. The reaction was carried out for 2 hours by gradually increasing the temperature of the solution to 80°C.

After confirming the disappearance of the remaining isocyanate groups by infrared spectroscopy (IR analysis), the solution was cooled and the reaction was terminated, and then 1 part by mass of antioxidant (D-1) and 3 parts by mass of β-diketone compound (X-1) parts were added and mixed. As described above, a colorless and transparent solution containing a hydroxyl-terminated urethane prepolymer (UPH-39) for comparison was obtained.

Main manufacturing conditions and evaluation results are shown in Table 1-7 and Table 2-2.

(Production Example 49) (Single-stage polymerization method)

100 parts by mass of polyol (HA-6), 5 parts by mass of active hydrogen group-containing compound (HB-2), polyisocyanate ( N-1) 40 parts by mass, 10 parts by mass of an organic solvent (B-1) as a diluent, 100 parts by mass of a plasticizer (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were added and mixed. The reaction was carried out for 2 hours by gradually increasing the temperature of the solution to 80°C.

After completing the reaction by cooling the inner solution, 1 part by mass of antioxidant (D-1) and 3 parts by mass of β-diketone compound (X-1) were added and mixed. As described above, a colorless and transparent solution containing an isocyanate group terminal urethane prepolymer (UPN-1) for comparison was obtained.

Main manufacturing conditions and evaluation results are shown in Table 1-7 and Table 2-2.

(Production Example 50)

100 parts by mass of a polyol (HA-6), 5 parts by mass of an active hydrogen group-containing compound (HB-2), 10 parts by mass of an organic solvent (B-1) as a diluent and 100 parts by mass of a plasticizer (P-1) as a catalyst By mixing 0.01 parts by mass of octyltin dilaurate, 1 part by mass of antioxidant (D-1), and 3 parts by mass of β-diketone compound (X-1), a colorless and transparent polyol (PO-1) containing solution got

Main manufacturing conditions and evaluation results are shown in Table 1-7 and Table 2-2.

[Production of urethane-based adhesive and adhesive sheet]

(Examples 1-54, Comparative Examples 1-4)

A urethane prepolymer-containing solution or polyol-containing solution obtained in any one of the above production examples, a polyfunctional isocyanate compound (I), and optionally an organic solvent (B) were blended and stirred with a disper to obtain a urethane pressure-sensitive adhesive.

About the obtained adhesive, solid content concentration and the viscosity after leaving still at 25 degreeC from immediately after preparation for 3 hours, and pot life were evaluated.

As the base sheet, a 50 µm thick polyethylene terephthalate (PET) film (Lumira T-60, manufactured by Toray Corporation) was prepared. Using a comma coater (registered trademark), a urethane-based pressure-sensitive adhesive that was left still at 25° C. for 3 hours or less immediately after preparation was coated on one side of this base sheet so that the thickness after drying might be set to 12 µm. Then, the formed coating layer was dried at 100 degreeC for 2 minutes, and the adhesive layer was formed. On this adhesive layer, a 38-micrometer-thick peeling sheet (Superstack SP-PET38, the Lintec company make) was pasted, and the adhesive sheet was obtained. After curing for a predetermined time under the conditions of 23°C-50% RH, evaluation of initial curability, wettability, and re-peelability was performed. In addition, Comparative Example 4 is an example in which the pressure-sensitive adhesive was manufactured by the one-shot method.

The mixing composition of the pressure-sensitive adhesive and the evaluation results of the pressure-sensitive adhesive and the pressure-sensitive adhesive sheet are shown in Tables 3-1 to 3-2, and Tables 4-1 to 4-2.

[Evaluation results]

In Production Examples 1 to 46, a hydroxyl group-terminated urethane prepolymer (UPH), which is a reaction product of one or more active hydrogen group-containing compounds (HX) and one or more polyisocyanates (N), is included, and the solid content concentration is 80% by mass or more. , a hydroxyl-terminated urethane prepolymer containing solution having a viscosity of 8000 mPa·s or less at 25°C after standing at 25°C for 1 hour immediately after preparation was prepared. In all of these production examples, it was possible to synthesize a solution containing a hydroxyl-terminated urethane prepolymer having a reduced amount of the organic solvent used, a relatively high solid content concentration, and a relatively low viscosity.

In Examples 1-54, the solution containing the hydroxyl-terminated urethane prepolymer obtained in any one of Production Examples 1-46 and the polyfunctional isocyanate compound (I) were included, and the solid content concentration was 70% by mass or more or 80% by mass or more, and prepared The adhesive whose viscosity in 25 degreeC after leaving still at 25 degreeC for 3 hours from immediately after was 9000 mPa*s or less, or 5000 mPa*s or less was able to be prepared. In these Examples, pressure-sensitive adhesive sheets were manufactured using the pressure-sensitive adhesive that was left still at 25° C. for 3 hours immediately after preparation. In any Example, the coatability of the adhesive was favorable.

In all of Examples 1 to 54, an adhesive having a relatively low viscosity at the time of application was able to be manufactured with a reduced amount of the organic solvent used, a relatively high solid content concentration, and good coating ability. In all of these Examples, an adhesive with a good pot life could be manufactured, and an adhesive sheet with good initial stage curability, wettability, and re-peelability was able to be manufactured.

The hydroxyl-terminated urethane prepolymer-containing solution obtained in Preparation Example 47 had a low solids concentration, and the pressure-sensitive adhesive of Comparative Example 1 using the same had a low solids concentration and had a poor VOC reduction effect.

The hydroxyl-terminated urethane prepolymer-containing solution obtained in Preparation Example 48 had a high viscosity, and the pressure-sensitive adhesive of Comparative Example 2 using the same had high viscosity, poor pot life, and poor coatability.

The pressure-sensitive adhesive of Comparative Example 3 using the isocyanate group-terminated urethane prepolymer-containing solution obtained in Preparation Example 49 had poor pot life, and the pressure-sensitive adhesive sheet using the same had poor initial curability.

In Preparation Example 50, a polyol-containing solution was obtained, and in Comparative Example 4, an adhesive was prepared by a one-shot method using it. The adhesive sheet using this had poor initial curability.

[Table 1-1]

[Table 1-2]

[Table 1-3]

[Table 1-4]

[Table 1-5]

[Table 1-6]

[Table 1-7]

[Table 2-1]

[Table 2-2]

[Table 3-1]

[Table 3-2]

[Table 4-1]

[Table 4-2]

This invention is not limited to the said embodiment and an Example, A design change is possible as appropriate within the range which does not deviate from the meaning of this invention.

This application claims priority on the basis of Japanese Patent Application No. 2019-091953 for which it applied on May 15, 2019, and takes in all the indication here.

10, 20: adhesive sheet
11, 21: base material sheet
12, 22A, 22B: adhesive layer
13, 23A, 23B: release sheet

Claims (16)

It comprises a hydroxyl-terminated urethane prepolymer (UPH) which is a reaction product of at least one active hydrogen group-containing compound (HX) having a plurality of active hydrogen groups in one molecule and at least one polyisocyanate (N),
The hydroxyl-terminal urethane prepolymer containing solution for adhesives whose solid content concentration is 80 mass % or more, and the viscosity in 25 degreeC after leaving still at 25 degreeC immediately after preparation is 8000 mPa*s or less.
According to claim 1,
The at least one active hydrogen group-containing compound (HX) contains at least one polyol (HA) having a number average molecular weight of 1000 or more, and at least one active hydrogen group having a plurality of active hydrogen groups in one molecule having a number average molecular weight of less than 1000. A solution containing a hydroxyl-terminated urethane prepolymer comprising compound (HB).
3. The method of claim 1 or 2,
A solution containing a hydroxyl group-terminated urethane prepolymer, wherein the at least one polyol (HA) comprises a trifunctional or higher polyether polyol.
4. The method according to any one of claims 1 to 3,
The ratio (NCO/H) of the number of moles of isocyanate groups (NCO) of the at least one polyisocyanate (N) to the total number of moles of active hydrogen groups (H) of the compound (HX) having at least one active hydrogen group is 0.20-0.84, a solution containing hydroxyl-terminated urethane prepolymer.
5. The method according to any one of claims 1 to 4,
The hydroxyl-terminated urethane prepolymer (UPH) is a reaction product of an isocyanate-terminated urethane prepolymer (UPN), which is a reaction product of a polyol (HA) and a polyisocyanate (N), and an active hydrogen group-containing compound (HB), a hydroxyl-terminated urethane Solutions containing prepolymers.
6. The method according to any one of claims 1 to 5,
A solution containing a hydroxyl-terminated urethane prepolymer, wherein the at least one polyisocyanate (N) comprises isophorone diisocyanate.
7. The method according to any one of claims 1 to 6,
The active hydrogen group-containing compound (HB) is a hydroxyl-terminated urethane prepolymer-containing solution containing a primary hydroxyl group.
The adhesive containing the hydroxyl-terminal urethane prepolymer containing solution in any one of Claims 1-7, and a polyfunctional isocyanate compound (I).
9. The method of claim 8,
The adhesive whose solid content concentration is 80 mass % or more, and the viscosity in 25 degreeC after leaving still at 25 degreeC immediately after preparation is 5000 mPa*s or less.
10. The method according to claim 8 or 9,
The adhesive further comprising a plasticizer.
11. The method according to any one of claims 8 to 10,
Further comprising a β-diketone compound, the pressure-sensitive adhesive.
12. The method according to any one of claims 8 to 11,
Further comprising an antistatic agent, the pressure-sensitive adhesive.
13. The method according to any one of claims 8 to 12,
The pressure-sensitive adhesive, which further comprises one or more deterioration inhibitors selected from the group consisting of antioxidants, hydrolysis resistance, ultraviolet absorbers, and light stabilizers.
An adhesive sheet comprising a base sheet and an adhesive layer made of a cured product of the pressure-sensitive adhesive according to any one of claims 8 to 13.
A step of reacting at least one polyol (HA) having a number average molecular weight of 1000 or more and at least one polyisocyanate (N) in an excess ratio of isocyanate groups to produce an isocyanate group-terminated urethane prepolymer (UPN);
A step of reacting the obtained isocyanate group-terminated urethane prepolymer (UPN) with at least one active hydrogen group-containing compound (HB) having a plurality of active hydrogen groups in one molecule having a number average molecular weight of less than 1000;
The method for producing a solution containing a hydroxyl-terminated urethane prepolymer according to claim 2 .
A step of mixing at least the hydroxyl-terminated urethane prepolymer-containing solution and the polyfunctional isocyanate compound (I) to prepare an adhesive having a solid content concentration of 80% by mass or more;
forming a coating layer by coating the pressure-sensitive adhesive on the base sheet;
having a process of drying the coating layer,
The manufacturing method of the adhesive sheet of Claim 14 whose viscosity in 25 degreeC of the said adhesive at the time of coating is 5000 mPa*s or less.

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