Polyol compositions, urethane cured products, and urethane adhesives

Abstract

To provide a polyol composition that exhibits superior curability irrespective of polyol type, thickness, or curing temperature, contributing to polyurethane formation with exceptional moisture and heat resistance, a urethane cured product prepared with the polyol composition, and a urethane adhesive composed of the urethane cured product.SOLUTION: A polyol composition (F) comprises a polyol (A), a triazole derivative (C), and a hindered phenolic compound (D) with a molecular weight of 250 or more and 1000 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to polyol compositions. More specifically, to urethane cured products obtained from polyol compositions, and urethane adhesives containing urethane cured products. [Background technology]

[0002] Adhesives are used in various applications such as tapes, labels, stickers, decorative sheets, anti-slip sheets, and double-sided adhesive tapes. In recent years, they have also been used in a wide range of fields, including the adhesion of liquid crystal displays and touch panels in personal computers, televisions, and mobile phones.

[0003] Examples of adhesives include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, and oxyalkylene adhesives. In particular, recently, acrylic adhesives have been used in a wide range of applications, from strong adhesives with high tackiness to very weak adhesives with minimal tackiness.

[0004] However, acrylic adhesives present problems such as odor, skin irritation, and substrate contamination if acrylic monomers remain in the adhesive. Furthermore, acrylic adhesives tend to increase in adhesive strength and transferability over time after being applied to the substrate. This can easily lead to adhesive residue on the substrate and insufficient re-peelability. Additionally, because acrylic adhesives use comonomers with high glass transition temperatures to exhibit cohesive force, they suffer from insufficient impact resistance at low temperatures and poor cold resistance.

[0005] In contrast, urethane-based adhesives have the advantage of having a smaller molecular weight compared to acrylic adhesives and can easily adapt to changes in the shape of the adherend. Polyols such as polyalkylene oxides and urethane prepolymers using them are particularly widely used as raw materials for polyurethane.

[0006] Patent Document 1 discloses a urethane-forming composition which uses a polyalkylene oxide having a narrow molecular weight distribution and a remarkably low content of unsaturated monool, has low viscosity and excellent handleability, and a urethane pressure-sensitive adhesive having high flexibility and low-temperature properties obtained by using the same.

[0007] However, although cured urethane products obtained from various polyols including these and urethane prepolymers thereof exhibit heat resistance and moist heat resistance when used in normal environments, durability may not be sufficient in applications that require remarkably high moist heat resistance, and problems such as contamination of adherends, impairment of mechanical properties and adhesiveness may occur in use environments that become high-temperature and high-humidity during production processes or use environments. Therefore, there has been a demand for improving moist heat durability. In addition, when high temperature or long-time heating is required for curing to achieve increased thickness during curing, curability may become insufficient due to heat history, which tends to reduce the cohesive force of the cured urethane product, and thus there has also been a demand for improvement.

[0008] Therefore, there has been a demand for a polyol composition that contributes to the development of high curability and moist heat durability of cured urethane products regardless of the type of polyol, thickness, curing temperature, and the like. [Prior Art Literature] [Patent Literature]

[0009] [Patent Document 1] Japanese Patent No. 6891412 [Summary of the Invention] [Problem to be Solved by the Invention]

[0010] The present invention provides a polyol composition that has good curability regardless of the type of polyol, thickness, curing temperature and the like, and contributes to the formation of a polyurethane having remarkably excellent moist heat durability, a cured urethane product obtained by using the polyol composition, and a polyurethane pressure-sensitive adhesive composed of the cured urethane product. [Means for Solving the Problem]

[0011] As a result of intensive studies to solve the above problems, the present inventors have surprisingly found that by combining two specific compounds in addition to a polyol, a polyol composition that contributes to forming a urethane cured product having good curability regardless of conditions such as the use of a polyol having relatively low moist heat resistance, high thickness, and high temperature, and exhibiting remarkably excellent moist heat resistance durability, and have completed the present invention.

[0012] That is, each aspect of the present invention is the following [1] to

[16] . [1] A polyol composition (F) comprising a polyol (A), a triazole derivative (C), and a hindered phenol compound (D) having a molecular weight of 250 or more and 1000 or less [2] The polyol composition (F) according to [1], wherein the content of the triazole derivative (C) in the polyol composition (F) is 0.001% by mass or more and less than 0.1% by mass, the content of the hindered phenol compound (D) is 0.1% by mass or more and less than 0.7% by mass, and the mass ratio of the hindered phenol compound (D) to the triazole derivative (C) (hindered phenol compound (D) / triazole derivative (C)) is in the range of 1.5 to 30 times [3] The polyol composition (F) according to [1] or [2], which has an alkylene oxide residue having 3 carbon atoms, and has a number average molecular weight calculated by gel permeation chromatography of less than 100,000 [4] The polyol composition (F) according to any one of [1] to [3], which has an unsaturation degree of less than 0.020 meq / g [5] The polyol composition (F) according to any one of [1] to [4], wherein the triazole derivative (C) is a benzotriazole derivative having one or more phenolic hydroxyl groups [6] The polyol composition (F) according to any one of [1] to [5], wherein the hindered phenol compound (D) has a long-chain alkyl group having 8 or more carbon atoms and an ester group [7] The polyol composition (F) according to any one of [1] to [6], which has a non-volatile content concentration of 90% by mass or more [8] A polyol composition (F) according to any one of [1] to [7], comprising a urethane prepolymer (E) of a polyol (A) and a polyisocyanate (B). [9] Polyol composition (F) according to [8], comprising a urethane prepolymer (E) containing alkylene oxide residues in the range of 50 to 99.5% by mass and polyisocyanate residues in the range of 0.5 to 10% by mass.

[10] Polyol composition (F) according to [8] or [9], comprising a urethane prepolymer (E) containing unsaturated groups in an amount of less than 0.03% by mass.

[11] Polyol composition (F) according to any one of [8] to

[10] , wherein the urethane prepolymer (E) is a reaction product of a bifunctional polyalkylene oxide (A1) having an unsaturation degree of less than 0.010 meq / g and a molecular weight calculated from the hydroxyl value in the range of 3000 to 20000 and a polyisocyanate (B).

[12] A polyol composition (F) according to any one of [8] to

[11] , wherein the average number of functional groups fave of the total polyols forming the urethane prepolymer (E) is in the range of 1.90 to 2.20.

[13] Polyol composition (F) according to any one of [8] to

[12] , wherein the polyisocyanate (B) comprises an aliphatic isocyanate, an alicyclic isocyanate, or a modified thereof, and forms a urethane prepolymer (E), and the average number of functional groups fave of the total polyisocyanates is in the range of 2.00 to 3.19. A urethane-forming composition (H) comprising a polyol composition (F) and an isocyanate compound (G) as described in any of

[14] [1] to

[13] . A urethane cured product (I) containing the reactants of the urethane forming composition described in

[15] and

[14] . A urethane adhesive comprising the urethane cured product described in

[16]

[15] . [Effects of the Invention]

[0013] The polyol composition of the present invention exhibits good curability regardless of the polyol type, thickness, curing temperature, etc., by promoting curing (solidification) through reaction with an isocyanate compound to obtain polyurethane, and can yield a urethane cured product with high moisture and heat resistance.

[0014] The urethane cured product of the present invention can be used in humid and hot environments regardless of the polyol type, and by using polyalkylene oxides, which have relatively low resistance to humid and hot conditions, it is easy to exhibit remarkably good flexibility and low-temperature properties. Therefore, it can be used in applications with large fluctuations in temperature and humidity, and is expected to follow the movement and shape changes of the adherend, as well as exhibiting remarkably good low-temperature properties. It can be suitably used in a wide range of applications such as sealants, paints, adhesives, and bonding agents.

[0015] In particular, the urethane adhesive using the urethane cured product of the present invention exhibits remarkably good moisture and heat resistance even with a flexible composition, making it especially suitable for use as a flexible, moisture and heat resistant urethane adhesive that offers excellent wettability and conformability to the adherend. [Modes for carrying out the invention]

[0016] A polyol composition (F) according to one aspect of the present invention will be described in detail below.

[0017] <Polyol composition (F)> The polyol composition (F) of the present invention comprises a polyol (A), a triazole derivative (C), and a hindered phenol compound (D) having a molecular weight of 250 to 1000.

[0018] By including a triazole derivative (C) in addition to a hindered phenol compound (D) with a molecular weight of 250 to 1000 in the polyol composition, the triazole derivative (C) acts as a compatibilizer for the hindered phenol compound (D), improving dispersibility in the urethane resin. This is thought to be due to the appropriate coordination of nitrogen to the metal catalyst, etc., resulting in milder catalytic activity and decomposition reactions during thermal curing at high thicknesses and high temperatures. This suppresses thermal degradation during curing and improves durability under humid heat conditions, resulting in remarkably good resistance to humid heat. Regardless of the use of polyols such as polyalkylene oxides and polyester polyols, which are particularly prone to becoming flexible and are susceptible to high temperatures and high humidity conditions, the resulting urethane cured product exhibits remarkably good resistance to humid heat. Furthermore, regardless of the use of polyols that are similarly susceptible to high temperatures and high humidity conditions, good curability is achieved even at high thicknesses and high temperatures. On the other hand, if the polyol composition (F) does not contain a hindered phenol compound (D) with a molecular weight of 250 to 1000, the heat and humidity resistance will be insufficient even if a triazole derivative is added. Therefore, depending on the curing conditions, the curing ability is likely to be insufficient due to thermal degradation, and it is difficult to significantly improve the heat and humidity resistance of the resulting urethane cured product. In other words, if the polyol composition (F) does not contain a triazole derivative (C) or a hindered phenol compound (D) with a molecular weight of 250 to 1000, a synergistic effect will not be observed. Even if the hindered phenol compound (D) or triazole derivative (C) is added alone, the curing ability will be insufficient under certain polyol species, high thickness, and high temperature conditions. Furthermore, it is difficult to significantly improve the heat and humidity resistance of the resulting urethane cured product, making it difficult to use in applications with large temperature and humidity fluctuations.

[0019] The number-average molecular weight of the polyol composition (F) is preferably less than 100,000. This makes it easier to lower the viscosity of the polyol composition (F), improves handling, and allows for a reduction in the amount of solvent and concentration used during manufacturing, resulting in a high VOC reduction effect.

[0020] In particular, a number-average molecular weight of 5,000 or more and less than 60,000 is preferred, most preferably 6,000 or more and less than 40,000, because it is easier to maintain a constant viscosity even when highly solidified, further suppressing molding defects due to liquid flow, and the resulting cured urethane is more likely to exhibit stable and high cohesive force.

[0021] Here, the number-average molecular weight of the polyol composition (F) was measured and calculated by gel permeation chromatography of the polyol composition (F) itself, using the same method as for polyalkylene oxides described later. Components with a molecular weight of 600 or less, such as solvents, ketoenol tautomers, phenolic antioxidants, and other additives with a molecular weight of 600 or less, were excluded from the calculation.

[0022] The unsaturated group content of the polyol composition (F) is preferably less than 0.020 meq / g, more preferably 0.015 meq / g or less, and most preferably in the range of 0.0001 to 0.010 meq / g, because this tends to increase the strength and cohesiveness of the resulting urethane cured product. Here, the unsaturated group content is measured or calculated for the composition even when it contains multiple polyol components, and can be measured in the same way as for polyalkylene oxide (A1) described later. However, if it contains multiple polyol components and the raw materials are known, it may be calculated from the amount of unsaturated groups in each raw material.

[0023] The polyol (A) content in the polyol composition (F) is preferably in the range of 1 to 99.9% by mass, as this makes it easier to achieve both high cohesiveness and high flexibility. More preferably, it is in the range of 60 to 99.8% by mass, as this provides a moderate viscosity, resulting in superior coating properties that are more stable regardless of crosslinking conditions, and also makes it easier to achieve both high cohesiveness and high flexibility. Most preferably, it is in the range of 80 to 99.7% by mass. Furthermore, when the polyol composition (F) contains a urethane prepolymer (E) consisting of polyol (A) and polyisocyanate (B), it is preferable that the content of the above components includes the content of the polyol (A) component in the urethane prepolymer (E), and it is preferable that the sum of the content of the polyol (A) structure in the urethane prepolymer (E) and the content of polyol (A) that does not form the urethane prepolymer falls within the above preferred content range.

[0024] The polyol composition (F) preferably contains 60% by mass or more alkylene oxide residues, more preferably 80-99.9% by mass, and most preferably 95-99.8% by mass, because the resulting urethane cured product tends to have remarkably good wettability and exhibits a characteristically low glass transition temperature, resulting in excellent low-temperature properties. Here, the alkylene oxide residue content refers to the content within the molecule if the polyol is a single component, or the content relative to the multiple components if it contains multiple components. The content of each residue can be calculated by NMR or the like, but it may also be calculated by separating each component or performing alkaline decomposition and analyzing each fraction as needed. If the raw materials in the composition are known, the content may also be calculated from the charging ratio of each raw material and the alkylene oxide residue content of each raw material. For example, the alkylene oxide residue content may be calculated by dividing the number average molecular weight, which is calculated from the hydroxyl value of the polyalkylene oxide (A1) used to form the urethane prepolymer (E), and the polyalkylene oxide (A1) mixed with it, by the amount of each initiator residue and the amount of unsaturated group, and the charging ratio of each raw material.

[0025] Furthermore, while the alkylene oxide residue is not particularly limited, examples include alkylene oxide residues having 2 to 20 carbon atoms. It is preferable to include alkylene oxide residues having 2 to 3 carbon atoms because the polyol composition (F) tends to be liquid and highly transparent, and a urethane cured product with good mechanical properties is easily obtained. For example, propylene oxide residues and ethylene oxide residues are more preferable alkylene oxide residues, and the most preferred is an alkylene oxide residue having 3 carbon atoms, specifically a propylene oxide residue.

[0026] In particular, to easily improve the mechanical properties of the cured urethane, the polyol composition (F) preferably contains 60% by mass or more of C3 alkylene oxide residues, more preferably 80 to 99.9% by mass, and most preferably in the range of 95 to 99.8% by mass. Furthermore, to easily improve resistance to humid heat, ethylene oxide residues, which are C2 alkylene oxide residues, may also be included. If included, the content is preferably 0.1% by mass or more, more preferably 0.5 to 15% by mass, and most preferably in the range of 1 to 13% by mass, as this makes it easier to maintain cohesive force after humid heat conditions and tackiness after holding humid heat conditions.

[0027] In particular, the resulting urethane cured product is more likely to exhibit significantly better wettability and low-temperature properties, therefore, the polyol composition (F) preferably contains a polyalkylene oxide structure with a number average molecular weight of 3000 or more, and especially preferably contains a bifunctional polyalkylene oxide structure with a number average molecular weight of 3000 or more. The content of the polyalkylene oxide structure with a number average molecular weight of 3000 or more is not particularly limited, but it is preferably 50% by mass or more in the polyol composition (F), more preferably 70 to 99.9% by mass, and most preferably in the range of 95 to 99.8% by mass. The polyalkylene oxide structure with a number average molecular weight of 3000 or more is a structure derived from either the polyol (A) or the urethane prepolymer (E) in the polyol composition, or both, and its content can be measured and calculated in the same way as the alkylene oxide residue.

[0028] Furthermore, although not particularly limited, the polyol composition (F) preferably contains aromatic structures such as aromatic amine residues, sugar residues with 6 or more carbon atoms, polyoxytetramethylene residues, and polycarbonate residues in a range of 50% by mass or less, more preferably 20% by mass or less, and most preferably intentionally omitted, as these components tend to exhibit better flexibility. The preferred content range for the above structures does not include solvents that are removed by volatilization, such as benzene and toluene, or additives that are non-reactive with isocyanates, such as ester-based plasticizers. As for alicyclic structures, although not particularly limited, they preferably contain a range of 20% by mass or less, more preferably 5% by mass or less, and most preferably intentionally omitted, as these components tend to exhibit higher flexibility more stably.

[0029] The content of each residue in the polyol composition (F) may be determined by decomposing it into individual raw materials by methods such as Corish decomposition or alkaline decomposition as needed, and determining the composition ratio. Alternatively, if the charging ratio of each raw material is known, it may be calculated from the charging ratio and the proportion in the chemical structure of each raw material.

[0030] The viscosity of the polyol composition (F) at 25°C is not particularly limited, but is preferably in the range of 0.1 to 30 Pa·s, more preferably in the range of 0.5 to 20 Pa·s, and most preferably in the range of 3 to 15 Pa·s, as it makes it less prone to liquid flow and easier to form uniformly from thin to thick films. In particular, it is preferable that the viscosity remains constant even when volatile components evaporate during the drying process or when heated, as this makes it less likely for molding defects such as liquid flow, void formation, and increased thickness at the coating end to occur during the coating and curing processes. Therefore, although not particularly limited, it is preferable that the non-volatile content is 90% by mass or more and the viscosity is in the range of 0.1 to 30 Pa·s, more preferably in the range of 0.5 to 20 Pa·s with a non-volatile content of 99% by mass or more and the viscosity is in the range of 3 to 15 Pa·s with a non-volatile content of 99.5% by mass or more. For similar reasons, the viscosity at 80°C is preferably in the range of 0.05 to 20 Pa·s, more preferably in the range of 0.1 to 15 Pa·s, and most preferably in the range of 0.5 to 10 Pa·s. Such properties are easily obtained by using relatively high molecular weight polyols or their urethane prepolymers, and it is particularly preferable to include urethane prepolymer (E) because the viscosity does not change easily even at high temperatures and it exhibits excellent high-thickness moldability.

[0031] The polyol composition (F) is preferably a uniform liquid at 25°C and does not separate upon standing. It is particularly preferable that it is transparent to the naked eye, as this improves visibility, makes it easier to detect foreign matter, and tends to result in a transparent cured urethane product. In particular, it is preferable that the haze value at a width of 100 μm be 5% or less, more preferably 3% or less, and most preferably 1% or less. Alternatively, the haze value of the polyol composition (F) may be calculated by coating it onto a PET substrate or the like and dividing by the haze value of the substrate.

[0032] The polyol composition (F) may contain other active hydrogen compounds in addition to the polyol (A), and is not particularly limited. For example, it may contain monools such as polyalkylene oxides having one hydroxyl group to improve coating properties and leveling properties, and it may also contain amine compounds such as amino alcohols and polyamines, thiol compounds such as mercaptoethanol and dithiols, water, and carboxylic acid compounds to impart adhesion and tackiness.

[0033] When other active hydrogen compounds are included in addition to polyol (A), it is preferable that the amount be in the range of 45% by mass or less, as this makes it easier to maintain and improve better flexibility and moisture and heat resistance. In particular, it is preferable that the amount be in the range of 25% by mass or less, more preferably 8% by mass or less, and most preferably in the range of 0.01 to 4% by mass.

[0034] The polyol composition (F) may contain a triazole derivative (C), a hindered phenol compound (D) with a molecular weight of 250 to 1000, and various known additives such as ketoenol tautomer compounds, acid retarders, other retarders, urethane catalysts, antistatic agents, plasticizers, leveling agents, rheology control agents, lubricants, solvents, chain extenders, fillers, stabilizers, antioxidants, and other additives.

[0035] In particular, it is preferable to include a urethane catalyst containing a metal component because it is easier to achieve better curability, and a ketoenol tautomer compound because the catalytic activity can be adjusted to improve moldability.

[0036] The urethane catalyst containing a metal component is not particularly limited as long as it is a compound that contains a metal component and exhibits urethane activity, but examples include organometallic compounds containing one or more of the following metals: Fe, Sn, Zr, Ti, and Al.

[0037] As a urethane catalyst containing a preferred metal component, it is even more preferable to use one or more metal chelate catalysts such as Fe chelate catalysts, Zr chelate catalysts, Ti chelate catalysts, and Al chelate catalysts, as these allow for easy adjustment of reactivity and suppress the decrease in curability when adding triazole derivatives and hindered phenol compounds, thereby improving moisture and heat resistance. Most preferably, an Fe chelate catalyst is used.

[0038] The Sn catalyst is not particularly limited, but examples include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diversate, and dibutyltin bis(acetylacetonate).

[0039] While not particularly limited, examples of metal chelating catalysts include iron trisacetylacetonate as an Fe chelating catalyst, zirconium tetraacetylacetonate and zirconium ethylacetoacetate as Zr chelating catalysts, titanium acetylacetonate and titanium ethylacetoacetate as Ti chelating catalysts, and aluminum trisacetylacetonate as an Al chelating catalyst.

[0040] The content of the urethane catalyst containing a metal component in the polyol composition (F) is not particularly limited, but is preferably 0.001% by mass or more and 0.5% by mass or less. In particular, the content of the urethane catalyst containing a metal component is preferably in the range of 0.001% by mass to 0.1% by mass, and more preferably in the range of 0.005% by mass to 0.07% by mass, as this improves moldability and tends to result in a better appearance of the resulting urethane coating film.

[0041] The ketoenol tautomer compounds that are preferably included in the polyol composition (F) of the present invention are preferably one or more of methyl acetoacetate, ethyl acetoacetate, and acetylacetone, as these are good for adjusting catalytic activity and improving moldability.

[0042] When a ketoenol tautomer compound is included, its content is preferably such that the molar ratio (ketoenol tautomer compound / metal catalyst) to the urethane catalyst containing the metal component is 1 or more, more preferably in the range of 3 to 5000, as this tends to improve moldability. The content in the polyol composition (F) is preferably in the range of 0.001% to 20% by mass, and more preferably in the range of 0.05% to 5% by mass.

[0043] The acid retarder is not particularly limited, but it is preferable to include an acid with a pKa of 5.0 or less. Examples of such acids with a pKa of 5.0 or less include hydrochloric acid, nitric acid, phosphoric acid, and phosphorus-based acid retarders such as acid phosphate esters having 2 to 20 carbon atoms, such as ethyl acid phosphate and 2-ethylhexyl acid phosphate. Among these, phosphorus-based acid retarders are preferred because they tend to have a good balance of reactivity and physical properties. The content of the acid retarder in the polyol composition (F) when using it is preferably in the range of 0.001% to 1% by mass, and more preferably in the range of 0.005% to 0.1% by mass.

[0044] The chain extender is not particularly limited and includes, for example, glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, pentaerythritol, and low molecular weight polyalkylene glycols with a molecular weight of 1000 or less; and polyhydric amines such as ethylenediamine, N-aminoethylethanolamine, piperazine, isophoronediamine, and xylylenediamine. Among these, polyhydric amines are preferred because they form urethane urea and make it easy to obtain urethanes with good physical properties.

[0045] Antistatic agents are not particularly limited, but examples include alkali metal salts and ionic liquids, such as lithium salts like lithium bis(trifluoromethanesulfonylimide), quaternary ammonium salts, imidazolium salts, phosphonium salts, and pyridinium salts.

[0046] Examples of plasticizers are not limited to fatty acid esters, alicyclic esters, and polyether esters, and include epoxidized fatty acid esters, myristic acid esters, and terminal ester-modified compounds of polyalkylene glycols.

[0047] Examples of rheology control agents include organic rheology control agents such as urea derivatives and lecithin, and inorganic rheology control agents such as fumed silica.

[0048] Examples of stabilizers, antioxidants, and other additives are not limited to those mentioned above, but include benzophenone-based UV absorbers, triazine-based UV absorbers, cyanoacrylate-based UV absorbers, hindered amine-based light stabilizers, phosphite-based processing stabilizers, sulfur-based heat-resistant stabilizers, hydroxylamine-based processing stabilizers, melamine-based flame retardants, imidazole-based antioxidants, quinoline-based antioxidants, hydroquinone-based antioxidants, etc. Examples include commercially available products from BASF such as the Ilgastab series, Irgaphos series, Irganox series, Simasorb series, Ubinal series, Tinuvin series, and Melapool series, which can be appropriately selected and used depending on the application and required properties.

[0049] Furthermore, although not particularly limited, due to the significant environmental impact, it is preferable that the urethane catalyst and the like contain no tin compounds at a concentration of 1000 ppm or more, more preferably 50 ppm or more, and most preferably intentionally omitted. Similarly, although not particularly limited, due to the significant environmental impact, it is preferable that the solvent contains no solvents at a concentration of 30% by mass or more, more preferably 10% by mass or more. In particular, it is even more preferable that the solvent contains no solvents at a concentration of 5% by mass or more, and especially preferable that it contains no solvents at a concentration of 1% by mass or more, as this significantly reduces the environmental impact and also significantly improves the working environment. In this embodiment, volatile additives such as ketoenol tautomer compounds with a boiling point of 200°C or less are not included in the solvent, but it is most preferable that the volatile compounds, including volatile additives, contain no volatile compounds at a concentration of 1% by mass or more, and the polyol composition (F) of the present invention is easily obtained with such properties.

[0050] The method for producing the polyol composition (F) is not particularly limited, but is not limited as long as it can uniformly disperse the polyol and raw materials, and can be any conventionally known stirring method. Examples of stirring machines include general-purpose stirrers, rotary-orbit mixers, disperser dispersers, dissolvers, kneaders, mixers, laboplast mills, planetary mixers, etc. If the polyol composition is liquid at the stirring temperature, general-purpose stirrers, rotary-orbit mixers, disperser dispersers, and dissolvers are preferably used. Furthermore, in order to uniformly and quickly dissolve and disperse each raw material, the mixture may be dispersed by heating from room temperature to high temperature, and since the polyol composition (F) of the present invention has high resistance to humid heat and heat, such preparation can be suitably adapted, and good curability can be maintained.

[0051] Furthermore, when the polyol composition (F) contains a urethane prepolymer (E), it can be prepared by first forming it at a temperature ranging from room temperature to 150°C and then mixing it with a polyol or triazole derivative (C), a hindered phenol compound (D) with a molecular weight of 250 to 1000, and any additives as needed at any temperature; or by first mixing the urethane prepolymer with the additives and then forming it at a temperature ranging from room temperature to 150°C and then mixing it with a polyol or triazole derivative (C), a hindered phenol compound (D) with a molecular weight of 250 to 1000, and any other additives as needed at any temperature. In addition, to adjust the non-volatile content, viscosity, and thixotropy index, dilution, concentration, dehydration, etc., may be performed at any time before, during, or after the formation of the urethane prepolymer.

[0052] The non-volatile content concentration of the polyol composition (F) is not particularly limited, but is usually in the range of 10 to 100% by mass, preferably in the range of 50 to 100% by mass, in order to obtain good coating properties when coating with a coating machine or the like.

[0053] In particular, the polyol composition (F) of the present invention is more suitable for use in a range of 80% by mass or more for nonvolatile content, as it allows for higher solid content differentiation and easily exhibits the characteristics of low VOC. More preferably, the nonvolatile content of the polyol composition (F) is in a range of 90% by mass or more, more preferably in a range of 95 to 99.9% by mass, and most preferably in a range of 99 to 99.9% by mass, as it allows for easy thickening with a high solid content and exhibits high curability and remarkably high resistance to moisture and heat even at high thicknesses, making it suitable for use regardless of the environment.

[0054] Furthermore, although not particularly limited, it is preferable that the polyol composition (F) of the present invention contains a component comprising a polyol (A), a triazole derivative (C), and a hindered phenol compound (D) with a molecular weight of 250 to 1000 in an amount of 70 to 100% by mass, and more preferably in an amount of 80 to 100% by mass, because it is highly likely to undergo high solid differentiation without the use of a large amount of additives such as plasticizers.

[0055] <Polyol (A)> Polyol (A) is not particularly limited, as long as it has at least one hydroxyl group at the polymer end, branched chain end, etc., but it is preferable that it has 2 to 8 hydroxyl groups in the molecule because the polyurethane obtained by reaction with an isocyanate compound tends to exhibit a good balance of physical properties, including flexibility. More preferably, it is a polyol having 2 to 4 hydroxyl groups in the molecule because it is readily available, offers a wide range of design possibilities, and is highly versatile, and most preferably, it is a polyfunctional polyol having 2 to 3 hydroxyl groups. When the average number of functional groups of polyol (A) is 1.0 or more and less than 2.0, it is preferable to use a polyfunctional isocyanate with 3 or more isocyanate functional groups, and optionally include a component having 2 or more active hydrogens that react with the isocyanate, such as water or diamine, to make the crosslinked structure denser.

[0056] While not particularly limited, polyurethane raw materials are preferably those with a hydroxyl value of 1 to 1000 (mgKOH / g), and more preferably in the range of 10 to 800 (mgKOH / g). The hydroxyl value can be calculated according to the method of JIS K1557 or other methods.

[0057] The molecular weight of polyol (A) is not particularly limited, but it is preferable that the number average molecular weight calculated by gel permeation chromatography is in the range of 1,000 to 50,000, more preferably in the range of 3,000 to 20,000, and most preferably in the range of 4,000 to 10,000, as this tends to result in significantly superior curability and flexibility.

[0058] Polyol (A) refers to commercially available polyols used in the production of polyurethanes. While not particularly limited, examples include polyether polyols obtained by ring-opening polymerization of alkylene oxides or tetrahydrofurans, polymer polyols obtained by radical polymerization of vinyl monomers in polyether polyols, polyester polyols obtained by polycondensation of polyhydric alcohols and polycarboxylic acids, polyesteramide polyols obtained by polycondensation of polyhydric alcohols, polycarboxylic acids, and amino alcohols, polylactone polyols obtained by ring-opening polymerization of lactones, polycarbonate polyols obtained by polycondensation of polyhydric alcohols and carbonates, acrylic polyols, polybutadiene polyols and their hydrogenated derivatives, polyisoprene polyols and their hydrogenated derivatives, partially saponified ethylene-vinyl acetate copolymers, natural oil-based polyols such as soybean oil and castor oil, halogen and / or phosphorus-based polyols, phenolic polyols, and the like. These polyols may be used individually or in mixtures of two or more.

[0059] Examples of polyester polyols include compounds derived from dibasic acids and polyhydric alcohols. While not particularly limited, examples include polyester polyols derived from adipic acid, orthophthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, succinic acid, azelaic acid, sebacic acid, linosylic acid, dimethyl terephthalate, and polyethylene terephthalate. Also, lactone-based polyester polyols obtained by ring-opening polymerization of cyclic esters such as ε-caprolactone and methylvalerolactone are also examples.

[0060] Examples of polyether polyols include polyether polyol compounds obtained by ring-opening addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, epichlorohydrin, or tetrahydrofuran to initiators such as ethylenediamine, tolylenediamine, sucrose, amino alcohol, butanol, glycerin, diethylene glycol, or low molecular weight polypropylene glycol with a molecular weight of 1000 or less.

[0061] Examples of halogenated and / or phosphorus-based polyols include halogenated polyols obtained by ring-opening polymerization of trichlorobutylene oxide, epichlorohydrin, epibromohydrin, etc., halogenated polyols such as brominated pentaerythritol / sucrose polyols and tetrabromophthalate polyesters, and phosphorus-based polyols obtained by adding alkylene oxide to phosphoric acid compounds.

[0062] Examples of phenolic polyols include Mannich polyols obtained by Mannich modification of phenol or phenol derivatives such as nonylphenol and alkylphenol using formaldehyde and secondary amines such as diethanolamine, ammonia, or primary amines, followed by ring-opening addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide.

[0063] In particular, polyalkylene oxide residues and polyester residues tend to have low resistance to moisture and heat in conventional formulations, but the addition of a triazole derivative (C) and a hindered phenol compound (D) with a molecular weight of 250 to 1000 significantly improves resistance to moisture and heat. Since these compounds are highly versatile and readily available, it is preferable to include one or more polyester polyols or polyether polyols. The proportion of polyester polyols and / or polyether polyols is preferably in the range of 10 to 100 parts by weight per 100 parts by weight of polyol (A).

[0064] Furthermore, flexibility is significantly improved, and although resistance to humid and heat is usually low, the addition of a triazole derivative (C) and a hindered phenol compound (D) with a molecular weight of 250 to 1000 significantly improves resistance to humid and heat. Therefore, it is particularly preferable to include a polyalkylene oxide (A1) obtained by ring-opening addition polymerization of an alkylene oxide with respect to an initiator as the polyol (A).

[0065] A more preferable polyalkylene oxide (A1) is not particularly limited, but it is preferable to include a polyalkylene oxide having two hydroxyl groups, having a degree of unsaturation of less than 0.010 meq / g and a molecular weight calculated from the hydroxyl value in the range of 3000 to 20000, as this tends to result in good re-peelability, wettability, flexibility, and low-temperature properties.

[0066] The degree of unsaturation of the polyalkylene oxide (A1) is preferably 0.010 meq / g or less. This allows the curing (solidification) of the urethane prepolymer (E) obtained using it to be faster when reacted with isocyanate crosslinking agents, etc., improving curability and thus improving the strength and cohesiveness of the resulting cured urethane product. More preferably, it is 0.007 meq / g or less, and most preferably 0.004 meq / g or less, as this significantly reduces the amount of low molecular weight components and characteristically improves stain resistance and re-peelability.

[0067] Here, the "degree of unsaturation (meq / g)" of polyalkylene oxide (A1) refers to the amount of unsaturated groups contained per gram of polyalkylene oxide, and corresponds to the number of unsaturated monools contained in the polyalkylene oxide. In other words, a higher degree of unsaturation means there are more unsaturated monools, and a lower degree of unsaturation means there are fewer unsaturated monools.

[0068] In this embodiment, the degree of unsaturation of polyalkylene oxide (A1) was measured in accordance with the NMR method described in Polymer Science, 1993, 50, 2, 121-126. In this embodiment, since the target of measurement is polyalkylene oxide (A1) with significantly low unsaturated monool content, the number of integration cycles in the NMR measurement was set to 500 or more in order to improve the measurement accuracy.

[0069] When using polyalkylene oxide (A1), although not particularly limited, it is preferable that the number average molecular weight calculated from the hydroxyl value is in the range of 3,000 to 20,000, as this tends to increase the cohesive force of the resulting polyurethane. More preferably, it is 3,500 to 15,000, and most preferably 4,000 to 10,000, as this allows the resulting polyol composition (F) to easily undergo high solid differentiation at a constant viscosity and further improves the wettability, flexibility, and low-temperature properties of the cured urethane.

[0070] The number-average molecular weight of polyalkylene oxide (A1) can be calculated from the hydroxyl value of polyalkylene oxide (A) calculated by the method described in JIS K-1557-1, and the number of hydroxyl groups in one molecule of polyalkylene oxide (A1).

[0071] The polyalkylene oxide (A1) preferably has a molecular weight distribution (weight-average molecular weight (Mw) / number-average molecular weight (Mn); Mw / Mn) of 1.1 or less, more preferably 1.06 or less, and most preferably in the range of 1.005 to 1.039. A Mw / Mn within this range is preferable because it reduces the amount of low-molecular-weight substances that cause contamination, thus leading to better stain resistance. The molecular weight distribution (Mw / Mn) can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0072] The polyalkylene oxide (A1) preferably contains a bifunctional polyalkylene oxide having two hydroxyl groups. Including the bifunctional polyalkylene oxide (A1) makes it easier for the resulting urethane cured product (H) to become linearly high in molecular weight, resulting in a more significantly flexible urethane cured product. Furthermore, the inclusion of a triazole derivative (C) and a hindered phenol compound (D) with a molecular weight of 250 to 1000 results in high curability, making it easier to improve mechanical properties such as good tackiness, adhesion, and elongation.

[0073] The polyalkylene oxide (A1) preferably contains an alkylene oxide residue with 3 or more carbon atoms in one molecule. The alkylene oxide residue with 3 or more carbon atoms is not particularly limited, and examples include alkylene oxide residues with 3 to 20 carbon atoms. Specifically, examples include propylene oxide residues, 1,2-butylene oxide residues, 2,3-butylene oxide residues, isobutylene oxide residues, butadiene monooxide residues, pentene oxide residues, styrene oxide residues, cyclohexene oxide residues, etc. Among these alkylene oxide residues, propylene oxide residues are preferred because the raw materials for obtaining polyalkylene oxide (A) are readily available and the resulting polyalkylene oxide (A1) has high industrial value.

[0074] Furthermore, polyalkylene oxide (A1) may contain only a single alkylene oxide residue with 3 or more carbon atoms, or it may contain two or more types of alkylene oxide residues. When two or more types of alkylene oxide residues are included, for example, one type of alkylene oxide residue may be linked in a chain, and the other alkylene oxide residues may be linked in a chain, or two or more types of alkylene oxide residues may be linked randomly. In addition, polyalkylene oxide (A1) may contain ethylene oxide residues with 2 carbon atoms in addition to alkylene oxide residues with 3 or more carbon atoms. The content of ethylene oxide residues in polyalkylene oxide (A1) is preferably 50% by mass or less, more preferably 30% by mass or less, and most preferably not included, because it results in low crystallinity, poor solidification at low temperatures, and good moldability.

[0075] <Triazole derivative (C)> The polyol composition (F) of the present invention contains a triazole derivative (C).

[0076] The polyol composition contains a hindered phenol compound (D) with a molecular weight of 250 to 1000, in addition to a triazole derivative (C). This acts as a compatibilizer for the hindered phenol compound (D), improving dispersibility in the urethane resin. Furthermore, nitrogen is appropriately coordinated to the metal catalyst, which is thought to have a milder catalytic activity and decomposition reaction during thermal curing at high thicknesses and high temperatures. This suppresses thermal degradation during curing and improves durability under humid conditions, resulting in remarkably good resistance to humid heat. Regardless of the use of polyols, which are conventionally sensitive to heat and high humidity conditions, the resulting urethane cured product exhibits excellent resistance to humid heat. Similarly, good curability is achieved even at high thicknesses and high temperatures, regardless of the use of polyols, which are also sensitive to heat and high humidity conditions.

[0077] If the polyol composition does not contain a triazole derivative (C), even if a hindered phenol compound (D) with a molecular weight of 250 to 1000 is used, it is difficult to achieve good curability under high thickness and high temperature conditions, and the resulting urethane cured product does not exhibit the desired moisture and heat resistance. Furthermore, it is difficult to suppress contamination of the adherend and reduction of resin strength while maintaining flexibility, making it difficult to use.

[0078] The content of the triazole derivative (C) in the polyol composition (F) is not particularly limited, but is preferably 0.0001% by mass or more and less than 3.0% by mass. In particular, it is preferably 0.001% by mass or more and less than 0.1% by mass, more preferably 0.001% by mass or more and 0.090% by mass or less, even more preferably 0.001% by mass or more and 0.07% by mass or less, and most preferably 0.01% by mass or more and 0.05% by mass or less, as this provides a greater effect in improving moisture and heat resistance, and reduces bleeding from the urethane cured product and provides excellent stain resistance.

[0079] The weight ratio of the hindered phenol compound (D) to the triazole derivative (C) in the polyol composition (F) (hindered phenol compound (D) / triazole derivative (C)) is not particularly limited, but is preferably in the range of 0.01 to 100 times. In particular, the range is more preferably in the range of 1.5 to 30 times, even more preferably in the range of 2.0 to 30 times, especially preferably in the range of 6.0 to 25 times, and most preferably in the range of 5 to 20 times, because the hindered phenol compound (D) and the triazole derivative (C) are more compatible, less prone to bleeding under humid heat conditions, have excellent stain resistance, and more remarkably good curability and humid heat durability are more easily and stably exhibited.

[0080] The triazole derivative (C) in the polyol composition (F) is not particularly limited as long as it contains a triazole structure with three nitrogen atoms in a five-membered ring. Compounds that do not contain three nitrogen atoms, such as triazole derivatives, have little effect in suppressing thermal degradation during curing and improving durability under humid heat conditions, which is thought to be due to the effect of nitrogen appropriately coordinating to metal catalysts, etc., and thus moderating catalytic activity and decomposition reactions during thermal curing at high thickness and high temperature. As a result, they are difficult to use due to insufficient curability and humid heat resistance.

[0081] Examples of triazole derivatives (C) include 1,2,4-triazole derivatives and 1,2,3-triazole derivatives, which can be suitably used.

[0082] In particular, it is preferable to include one or more benzotriazole derivatives, which are a type of 1,2,3-triazole derivative, because they exhibit less thermal degradation during curing, maintain higher curability, and easily form urethane cured products with high resistance to moisture and heat. Furthermore, it is preferable for benzotriazole derivatives to have one or more phenolic hydroxyl groups because they exhibit better curability, and it is even preferable for them to have a substituent at the ortho position of the phenolic hydroxyl group because they are less likely to be deactivated by reaction with isocyanates and stably improve resistance to moisture and heat. Preferred substituents at the ortho position of the phenolic hydroxyl group include quaternary substituents such as t-butyl groups, tertiary substituents such as triazolyl groups, and secondary substituents such as methylene groups. It is also preferable for the triazole derivative to have an alkyl group or ester group at the para position of the phenolic hydroxyl group because it makes it easier to liquefy the triazole derivative, has good compatibility, is less prone to coating unevenness, and easily forms a urethane with a transparent appearance.

[0083] Triazole derivatives (C) are less prone to volatilization and bleeding from urethane during curing, which improves curability and stain resistance. They also have better affinity with hindered phenol compounds, improving compatibility and enhancing moisture and heat resistance. Therefore, their molecular weight is preferably in the range of 100 to 2000, more preferably in the range of 200 to 1000, and most preferably in the range of 300 to 700. While not particularly limited, these triazole derivatives (C) are preferably liquid at room temperature because they have excellent compatibility with hindered phenol compounds (D) and urethane resins, and the resulting urethane tends to have stable and good moisture and heat resistance.

[0084] Examples of 1,2,4-triazole derivatives include compounds represented by the following general formula (1). These also include their tautomers.

[0085] [ka]

[0086] (In formula (1), R1, R2, and R3 are not particularly limited, and the type and presence or absence of substituents can be arbitrarily selected.)

[0087] Examples of R1, R2, and R3 include alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, hydroxy, halogen, polyoxyalkylene, and hydrogen atoms.

[0088] Examples of 1,2,4-triazole derivatives include 4-amino-1,2,4-triazole, 1,2,4-triazole, and 3-mercapto-1,2,4-triazole, which can be suitably used.

[0089] Examples of 1,2,3-triazole derivatives include compounds represented by the following general formula (2). These also include their tautomers.

[0090] [ka]

[0091] (In formula (2), R1, R2, and R3 are not particularly limited, and the type and presence or absence of substituents can be arbitrarily selected.)

[0092] Examples of R1, R2, and R3 include alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, hydroxy, halogen, polyoxyalkylene, and hydrogen atoms. Furthermore, R1 and R2 in the formula may be independent or bonded together to form rings such as aryl, heteroaryl, cycloalkyl, and cycloalkenyl.

[0093] Benzotriazole derivatives are 1,2,3-triazole derivatives that have a benzene ring structure containing the carbon atoms at positions 4 and 5 of the triazole molecule, and are not particularly limited, but include compounds represented by the general formula (3) below. These also include tautomers.

[0094] [ka]

[0095] (In formula (3), R1, R2, R3, R4, and R5 are not particularly limited, and the type and presence or absence of substituents can be arbitrarily selected.)

[0096] Examples of R1, R2, R3, R4, and R5 include alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, hydroxy, halogen, polyoxyalkylene, and hydrogen atoms. In particular, it is preferable to have a phenyl ring structure directly attached to R5 because it has high resistance to moisture and heat and tends to result in good mechanical properties.

[0097] Examples of benzotriazole derivatives include 2,2'-[[(methyl-1H-benzotriazole-1-yl)methyl]imino]bisethanol (TT-LYK, manufactured by Johoku Chemical Industry Co., Ltd.), 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole (TT-LX, manufactured by Johoku Chemical Industry Co., Ltd.), carboxybenzotriazole (CBT-1, manufactured by Johoku Chemical Industry Co., Ltd.), 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole (BT-LX, manufactured by Johoku Chemical Industry Co., Ltd.), 1,2,3-benzotriazole, 6-(2-benzotriazolyl)-4-tert-octyl-6'-tert-butyl-4'-methyl-2,2'-methylenebisphenol (JAST-500, manufactured by Johoku Chemical Industry Co., Ltd.), and 2,2'-methylenebis[6-(2H-benzo Examples include triazole-2-yl)-4-tert-octylphenol (JF-832, manufactured by Johoku Chemical Industry), 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole (JF-83, manufactured by Johoku Chemical Industry), 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole (JF-80, manufactured by Johoku Chemical Industry), 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (JF-79, manufactured by Johoku Chemical Industry), 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (JF-77, manufactured by Johoku Chemical Industry), and 2-(2'-hydroxy-3',5'-bis(methylbenzyl)phenol)benzotriazole (Tinuvin 234, manufactured by BASF).

[0098] In particular, triazole derivatives (C) have better affinity with hindered phenol compounds (D), improving compatibility and enhancing the effect of improving moisture and heat resistance. Furthermore, they tend to be less prone to volatilization during curing and bleeding from urethane, resulting in improved curability and stain resistance. Therefore, it is preferable that they have one or more phenolic hydroxyl groups.

[0099] Examples of benzotriazole derivatives having a phenolic hydroxyl group include compounds in which one or more of R1, R2, R3, R4, and R5 in the above general formula (3) contain a phenolic hydroxyl group. The phenolic hydroxyl group refers to a hydroxyl group directly attached to the benzene ring. The aryl group containing the phenolic hydroxyl group may or may not be directly attached to the benzotriazole. However, it is preferable that the aryl group containing the phenolic hydroxyl group is directly attached to the benzotriazole because it promotes coordination of the triazole to metals, etc., making it easier to adjust the reactivity and suppressing thermal degradation and moist heat degradation, thereby exhibiting better curability.

[0100] In particular, compounds in which the isocyanate and phenolic hydroxyl group do not react easily and tend to have high curability are preferred, and although not particularly limited, examples include compounds represented by the following general formula (4). These also include tautomers.

[0101] [ka]

[0102] (In formula (4), R1, R2, R3, R4, R5, R6, R7, and R8 are not particularly limited, and the type and presence or absence of substituents can be arbitrarily selected.)

[0103] Examples of R1, R2, R3, R4, R5, R6, R7, and R8 include alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, hydroxy, halogen, polyoxyalkylene, and hydrogen. In particular, it is even more preferable that R8 in the general formula be a quaternary substituent such as a t-butyl group, a tertiary substituent such as a triazolyl group, or a secondary substituent such as a methylene group.

[0104] In particular, it is most preferable for R6 to have substituents such as alkyl ester groups, as it exhibits remarkably good compatibility with hindered phenol compounds, especially those with resins, and is more likely to exhibit remarkably high moisture and heat resistance when in liquid form. The alkyl ester structure that is most preferable to be included in R6 is an ester structure having an alkyl group with 8 or more carbon atoms and less than 30 carbon atoms, similar to the structure of the most preferable hindered phenol compound.

[0105] Compounds represented by general formula (4) include 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (BASF Tinuvin 571) and 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxybenzenepropionic acid (alkyl ester with 7 to 9 carbon atoms) (BASF Tinuvin 99-2). These compounds have good compatibility, and their curability improvement effect and humidity and heat resistance improvement effect are more significantly higher, making them the most suitable for use.

[0106] <Hindered phenol compound (D)> The polyol composition (F) is characterized by containing a hindered phenol compound (D). By including a hindered phenol compound (D) with a molecular weight of 250 to 1000 in addition to a triazole derivative (C) in the polyol composition, the affinity between the triazole derivative (C) and the hindered phenol compound (D) with a molecular weight of 250 to 1000 is increased, improving compatibility and making it easier to mix with the resulting urethane resin. This allows for remarkably good resistance to humidity and heat, and regardless of whether or not a polyol, which is relatively weak under high temperature and high humidity conditions, is used, the resulting urethane cured product can exhibit good resistance to humidity and heat. Similarly, regardless of whether or not a polyol, which is relatively weak under high temperature and high humidity conditions, is used, good curability is also achieved even at high thicknesses and high temperatures.

[0107] If the polyol composition does not contain a hindered phenol compound (D), the heat resistance is insufficient even when a triazole derivative (C) is used. Therefore, depending on the polyol used and the usage conditions, it is difficult to achieve stable and remarkably good curability regardless of the thermal history, such as high thickness or high temperature conditions. Furthermore, the resulting urethane cured product does not stably exhibit the desired heat resistance and lacks resistance to humid heat. In particular, it is difficult to suppress contamination of the adherend and reduction of resin strength while maintaining flexibility, making it difficult to use.

[0108] Furthermore, when the molecular weight of the hindered phenol compound (D) is less than 250, bleeding is likely to occur under humid heat conditions, making it difficult to consistently achieve significantly good resistance to humid heat. Moreover, it is prone to volatilization at high temperatures, contributing to VOCs and fog, and easily contaminating the environment and the substrate, making it difficult to use. On the other hand, when the molecular weight exceeds 1000, the affinity with the triazole derivative (C) and the resin decreases, reducing the effect of improving resistance to humid heat. In addition, dispersibility and compatibility with the resin tend to decrease, and the melting point tends to increase, resulting in poor handling and making it difficult to consistently achieve significantly good resistance to humid heat.

[0109] The content of the hindered phenol compound (D) in the polyol composition (F) is not particularly limited, but is usually less than 3% by mass. It is preferable that it be between 0.1% by mass and less than 0.7% by mass, as this allows for stable and more economical provision of moisture and heat resistance. In particular, it is preferable that it be between 0.15% by mass and less than 0.6% by mass, and more preferably between 0.2% by mass and less than 0.5% by mass, as this allows for significantly better moisture and heat resistance, reduces bleeding from the cured urethane product, and provides excellent stain resistance.

[0110] Hindered phenol compounds (D) with a molecular weight of 250 to 1000 are compounds having a bulky substituent as a sterically hindered substituent at the ortho position relative to the hydroxyl group of phenol, and in this embodiment, refer to compounds that do not contain a triazole structure. In other words, triazole (C) and hindered phenol (D) are different compounds. Furthermore, as long as a bulky substituent as a sterically hindered substituent is present at one ortho position relative to the hydroxyl group of phenol, the compound is not particularly limited. For example, a compound may have a bulky substituent as a secondary or higher sterically hindered substituent such as a t-butyl group at one ortho position, and a substituent with insufficient bulk, such as a primary alkyl group such as a methyl group, at the other ortho position. Such compounds can be suitably used in applications requiring short-term resistance to humidity and heat, and can be appropriately selected depending on the usage environment. In particular, it is preferable to have bulky substituents at both ortho positions because they tend to exhibit high resistance to humidity and heat over the long term.

[0111] Examples of bulky substituents include secondary or higher substituents such as quaternary substituents like t-butyl groups, tertiary substituents like isopropyl groups, and long-chain secondary substituents. For example, in addition to t-butyl groups, branched alkyl groups with 5 or more carbon atoms include linear or branched alkyl groups with one or two terminal alkyl groups being methyl groups and the others being linear or branched alkyl groups with 2 to 20 carbon atoms, linear or branched alkyl groups with 2 to 20 carbon atoms in all terminal alkyl groups, cycloalkyl groups with 5 to 10 carbon atoms, alkylcycloalkyl groups with 6 to 24 carbon atoms, aryl groups, heteroaryl groups, etc. In particular, bulky substituents are preferably tertiary or quaternary substituents, and most preferably quaternary substituents such as t-butyl groups, because they are bulky and sterically hindered near the hydroxyl group of phenol, making it easier to exhibit stable and high resistance to moisture and heat.

[0112] While not particularly limited, it is preferable to use more hindered phenol compounds (D) compared to triazole derivatives (C) in terms of economy and bleed resistance. However, it is preferable to have substituents at the para position of the phenolic hydroxyl group because they have higher compatibility, are less prone to coating unevenness, and easily form urethane with a transparent appearance. In particular, it is preferable to have alkyl groups, ester groups, phosphonate groups, amide groups, and alkylaryl groups. In particular, it is preferable to have long-chain alkyl groups with 8 or more carbon atoms and ester groups because they are more compatible with urethane resins and more significantly improve moisture and heat resistance.

[0113] The hindered phenol compound (D) is not particularly limited as long as its molecular weight is between 250 and 1000, but it is preferably in the range of 300 to 900, more preferably in the range of 350 to 800, and most preferably in the range of 380 to 700, because it is less prone to volatilization and bleeding from the urethane during curing, more significantly improves moisture and heat resistance, has good compatibility, is less likely to cause uneven coating of the resulting urethane, and easily forms a urethane with a transparent appearance.

[0114] While not particularly limited, these hindered phenol compounds (D) have excellent compatibility and dispersibility, dissolve and disperse easily at room temperature or relatively low temperatures, do not precipitate easily in polyol compositions, have excellent handling properties, disperse more uniformly in the resulting urethane, exhibit more stable moisture and heat resistance, and tend to have good coating film appearance such as transparency. Therefore, it is preferable that the melting point is 170°C or lower, more preferably 100°C or lower, and most preferably in the range of 30°C to 100°C, as this tends to result in less bleeding in the resulting cured urethane regardless of environmental conditions such as moisture and heat, and tends to have better stain resistance. For example, BASF's Chinuvin 99-2, which has a melting point of 50°C, is an example. In addition, if necessary, a trace amount of diluent of 10% by mass or less relative to the hindered phenol compound may be included to make it liquid or to improve dispersibility.

[0115] While not particularly limited, hindered phenol compounds include those represented by the following general formula (5). These also include their dimer and oligomer forms.

[0116] [ka]

[0117] (In formula (5), at least one of R1 and R5 is a secondary or higher sterically hindered substituent, and R2, R3, and R4 are not particularly limited, and the type and presence or absence of substituents can be arbitrarily selected.)

[0118] At least one of R1 and R5 is a secondary or higher sterically hindered substituent, such as secondary alkyl, tertiary alkyl, quaternary alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, or polyoxyalkylene. If only one of R1 or R5 has a secondary or higher sterically hindered substituent, the other R1 or R5 may be a hydrogen atom or a methyl group.

[0119] Examples of R2, R3, and R4 include alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, hydroxy, halogen, polyoxyalkylene, and hydrogen atoms.

[0120] R1, R2, R3, R4, and R5 in the formula may be independent or bonded together to form rings such as aryl, heteroaryl, cycloalkyl, or cycloalkenyl rings. The formula may also contain any substituents such as ether, thioether, ester, phosphonate, urethane, amide, or urea groups.

[0121] Examples of such hindered phenol compounds include 4-methyl-2,6-di-tert-butylphenol (BHT), [3-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]propyl], 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (Irganox 1010), 3-(3,5-di-t-butyl-4-hydroxyphenyl)stearyl propionate (Irganox 1076), 2,4-bis(octylthiomethyl)-6-methylphenol (Irganox 1520), isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (Irganox 1135), and 2,4-bis(dodecylthiomethyl) (L)-6-methylphenol, 2,2'-thiodiethylbis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propanamide], octyl-3,5-di-t-butyl-4-hydroxy-hydrocinnamic acid, 2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)mesitylene, calciumbis[3,5-di(t-butyl)-4- [Hydroxybenzyl(ethoxy)phosphinate], bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylenebis(oxyethylene)], 1,6-hexanediolbis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione , 4-[[4,6-bis(octylthio)-1,3,5-triazine-2-yl]amino]-2,6-di-t-butylphenol, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 4,4'-butylidenebis(6-t-butyl-m-cresol), 3,9-bis[1,1-dimethyl-2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.Examples include BASF's "Irganox" series and Adeka Corporation's "Adeka Stab" series, such as undecane and pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]. Of these, compounds with molecular weights between 250 and 1000 are suitable for use as hindered phenol compounds (D), excluding 4-methyl-2,6-di-tert-butylphenol (BHT), which has a molecular weight of 220 and high volatility and bleeding properties at high temperatures, and [3-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]propyl] 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (Irganox 1010), which has a high molecular weight of 1178 and a tetramer structure with low compatibility. Furthermore, it is sufficient to include one or more of these hindered phenol compounds (D), and two or more hindered phenol compounds (D), or a mixture of one or more hindered phenol compounds (D) and other hindered phenol compounds, etc., may also be used.

[0122] The hindered phenol compound (D) is preferably one that contains an ester structure, as it exhibits good compatibility and more stable resistance to moisture and heat. While not particularly limited, compounds represented by the following general formula (6) are preferably used. Dimer and oligomer forms of these compounds are also included and are even more preferable as they tend to exhibit better resistance to moisture and heat.

[0123] [ka]

[0124] (In formula (6), R1 and R5 are secondary or higher sterically hindered substituents, R3 is an alkyl group having 1 or more carbon atoms, and n is any value from 1 to 50. R2 and R4 are not particularly limited, and the type and presence or absence of substituents can be arbitrarily selected.)

[0125] R1 and R5 are secondary or higher sterically hindered substituents, such as secondary alkyl, tertiary alkyl, quaternary alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, and polyoxyalkylene. R2 and R3 are such as alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl or alkyl-substituted aryl, heteroaryl or alkyl-substituted heteroaryl, alkoxyalkyl, acyloxyalkyl, hydroxy, halogen, polyoxyalkylene, and hydrogen. Furthermore, R1, R2, R3, R4, and R5 in the formula may be independent or bonded together to form rings such as aryl, heteroaryl, cycloalkyl, and cycloalkenyl. The formula may also contain any substituents such as ether groups, thioether groups, ester groups, phosphonate groups, urethane groups, amide groups, and urea groups.

[0126] Preferred R1 and R5 include, in addition to t-butyl and isopropyl groups, branched alkyl groups having 5 or more carbon atoms, such as linear or branched alkyl groups with one or two terminal alkyl groups being methyl groups and the others being linear or branched alkyl groups with 2 to 20 carbon atoms, linear or branched alkyl groups with 2 to 20 carbon atoms in all terminal alkyl groups, cycloalkyl groups with 5 to 10 carbon atoms, alkylcycloalkyl groups with 6 to 24 carbon atoms, aryl groups, heteroaryl groups, etc. Among these, R1 in the general formula is preferably a quaternary or tertiary substituent with significant steric hindrance, as this facilitates the development of good moisture and heat resistance over a longer period.

[0127] In general formula (6), R3 preferably has an alkyl group having 2 or more carbon atoms, as this results in significantly better compatibility and dispersibility in polyol compositions, and when a urethane is formed, it is more likely to be uniform and exhibit good moisture and heat resistance more stably. More preferably, it has a long-chain alkyl group having 8 or more carbon atoms, as this results in significantly better compatibility. More preferably, it has a long-chain alkyl group having 8 to less than 30 carbon atoms, and most preferably, it has a long-chain alkyl group having 8 to less than 20 carbon atoms. Furthermore, by including one or more hindered phenol structures in R3, dimer or oligomer forms can be formed and are suitably used.

[0128] While R2 and R4 are not particularly limited, hydrogen atoms are preferred because they are readily available.

[0129] In general formula (6), n is preferably in the range of 2 to 10, and most preferably 2, because it is easier to achieve good compatibility and less prone to bleeding.

[0130] Such more preferred hindered phenol compounds (D) are not particularly limited, but compounds represented by the following general formula (7) are preferably used. These also include dimer and oligomer compounds.

[0131] [ka]

[0132] (In formula (7), R1 and R3 are quaternary or tertiary substituents, and R2 is an alkyl group having 8 or more carbon atoms and less than 30 carbon atoms.)

[0133] In particular, R1 and R3 are most preferably t-butyl groups because they do not react easily with isocyanate groups and tend to exhibit longer-term resistance to moisture and heat.

[0134] The above compounds are not particularly limited, but examples include stearyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (Irganox 1076) and isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (Irganox 1135). These compounds exhibit more significant improvements in curability and resistance to humid and heat, making them the most suitable for use.

[0135] <Urethane prepolymer (E)> The polyol composition (F) has a moderate viscosity and is excellent in terms of coating properties, handling properties, thick film coating, and thick film moldability. Therefore, it is preferable to include a urethane prepolymer of polyol and polyisocyanate, and in particular, it is preferable to include a urethane prepolymer (E) of polyol (A) and polyisocyanate (B).

[0136] The urethane prepolymer (E) is preferably hydroxyl-terminated because it does not thicken easily over time, the properties of the polyol composition are stable, and it is easy to handle. However, it is not particularly limited and may also be amino-terminated or other active hydrogen-terminated groups.

[0137] When forming a urethane prepolymer (E), the total sum of hydroxyl groups (M) of the polyol OH The sum of the NCO groups (M) of the polyisocyanate relative to the (M) NCO ) molar ratio (M NCO / M OH The total hydroxyl group (M) of the polyol is preferably less than 1.0, is easily obtained as a hydroxyl group terminus, and the polyol composition (F) has good storage stability and easily forms a urethane with excellent coating appearance stably. In particular, it is easy to obtain a urethane-forming composition (H) that exhibits a low thixotropy index (TI value), is less likely to generate gel-like substances or insoluble matter, has a constant viscosity, and has good coating properties regardless of conditions, thus making it easy to obtain a urethane-forming composition (H) with good coating properties. OH The sum of the NCO groups (M) of the polyisocyanate relative to the (M) NCO ) molar ratio (M NCO / M OHThe ratio is preferably 0.05 or more and 0.69 or less, more preferably 0.10 or more and 0.49 or less, and most preferably 0.15 or more and 0.45 or less.

[0138] The urethane prepolymer (E) can contain any residues, including various polyol residues as exemplified by polyol (A). In particular, the urethane prepolymer (E) is particularly suitable for use because it exhibits remarkably good resistance to moisture and heat even when it contains alkylene oxide residues or polyester residues, which tend to reduce resistance to moisture and heat. However, it is not particularly limited as it tends to exhibit remarkably good resistance to moisture and heat regardless of the presence or absence of such residues. Furthermore, it is preferable that the urethane prepolymer (E) contains one or more of either alkylene oxide residues or polyester residues, and a polyisocyanate residue as constituent components. It is more preferable to contain 30% by mass or more of alkylene oxide residues because the resulting urethane cured product tends to have remarkably good wettability and exhibits a remarkably low glass transition temperature. It is also preferable to contain polyisocyanate residues in the range of 0.01 to 20% by mass because it provides an excellent balance between the flexibility and cohesiveness of the urethane cured product, and makes it easy to achieve both curability and resistance to moisture and heat.

[0139] In particular, it is preferable that the alkylene oxide residues are contained in a range of 50 to 99.5% by mass and polyisocyanate residues in a range of 0.5 to 10% by mass, as this results in greater flexibility and superior conformability. Furthermore, the urethane prepolymer (E) is preferably contained in an unsaturated group of less than 0.03% by mass, and more preferably in an unsaturated group of less than 0.01% by mass, as this results in better curability.

[0140] The degree of unsaturation in the urethane prepolymer (E) is not particularly limited, but is preferably 0.010 meq / g or less because it tends to increase the strength and cohesive force of the resulting polyurethane, more preferably 0.007 meq / g or less, more preferably 0.003 meq / g or less, and most preferably in the range of 0.0001 to 0.0018 meq / g. In this embodiment, the content of unsaturated groups can be measured in the same way as the polyalkylene oxide (A1) exemplified in the polyol (A) above, but if each raw material is known, it may also be calculated from the degree of unsaturation of the raw materials and their composition ratio.

[0141] The alkylene oxide residue content in the urethane prepolymer (E) is preferably 50 to 99.5% by mass, more preferably in the range of 70 to 99.5% by mass, and most preferably in the range of 90 to 99.5% by mass.

[0142] Furthermore, while the alkylene oxide residue is not particularly limited, examples include alkylene oxide residues having 2 to 20 carbon atoms, which can be used. However, it is preferable to include alkylene oxide residues having 2 to 3 carbon atoms, as this makes it easier to obtain a liquid and highly transparent polyol composition (F) and a urethane cured product with good mechanical properties. For example, propylene oxide residues and ethylene oxide residues are more preferred alkylene oxide residues. In particular, to easily improve the mechanical properties of the cured urethane product, it is preferable that the urethane prepolymer (E) contains 30% by mass or more of propylene oxide residues, more preferably 50 to 99.5% by mass, especially preferably 70 to 99.5% by mass, and most preferably in the range of 90 to 99.5% by mass. Furthermore, to easily improve the resistance to moisture and heat, ethylene oxide residues may also be included, and if included, the content is preferably 0.1% by mass or more, more preferably 1 to 20% by mass, and most preferably in the range of 5 to 18% by mass.

[0143] In particular, the resulting urethane cured product is more likely to exhibit significantly better wettability and low-temperature properties, therefore, the urethane prepolymer (E) preferably contains a polyalkylene oxide structure with a number average molecular weight of 3000 or more. The content of the polyalkylene oxide structure with a number average molecular weight of 3000 or more is not particularly limited, but it is preferably 30% by mass or more in the urethane prepolymer (E), more preferably 50 to 99.5% by mass, particularly preferably 70 to 99.5% by mass, and most preferably in the range of 90 to 99.5% by mass. In particular, the polyalkylene oxide structure with a number average molecular weight of 3000 or more is preferably a polyol residue having two hydroxyl groups.

[0144] Furthermore, the urethane prepolymer (E) may contain polyol residues having three or more active hydrogen groups, and is not particularly limited, but it is preferable that the average number of functional groups of the raw material polyol used for prepolymer formation be low within the range in which cohesive force can be expressed, and the content of polyol residues having three or more active hydrogen groups in the urethane prepolymer (E) is preferably in the range of 50% by mass or less, and more preferably in the range of 0 to 10% by mass. In particular, the content of the initiator residue of a polyol having three or more active hydrogen groups in the urethane prepolymer (E) is preferably in the range of 0 to 5% by mass, most preferably in the range of 0 to 3% by mass, because it is more stable, has a high solid content and moderate viscosity, has excellent coating properties and productivity, and the resulting cured urethane product is flexible while maintaining cohesive force and exhibits better conformability. Examples of such initiator residues include trimethylolpropane residues, glycerol residues, and pentaerythritol residues.

[0145] While not particularly limited, the urethane prepolymer (E) preferably contains polyisocyanate residues in the range of 0.1 to 10% by mass, more preferably in the range of 0.3 to 5% by mass, as this provides an excellent balance of wettability and cohesiveness in the resulting cured urethane, and makes it easier to achieve both remarkably high ball tack and re-peelability. Among these, the range of 0.5 to 3% by mass is most preferable, as it makes the material more remarkably flexible while maintaining cohesiveness and improves conformability.

[0146] Furthermore, while the polyisocyanate residues are not particularly limited, examples include aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, aromatic polyisocyanate residues, or modified versions thereof. However, it is preferable to include aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, or modified versions thereof, as this tends to reduce the coloration of the polyol composition (F) and makes it easier to obtain a urethane cured product with higher flexibility. More preferably, it is preferable to use aliphatic polyisocyanate residues or modified versions thereof, as this makes it easier to obtain a urethane cured product that is remarkably flexible while maintaining high cohesive strength. Furthermore, while not particularly limited, the modified polyisocyanate residues include residues of modified products containing urethane groups such as adduct-type groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups, uretdione groups, or oxazolidone groups, as well as residues of condensates such as polymethylene polyphenylene polyisocyanate (polymeric MDI). Modified residues containing two or more of these modified structures, such as urethane / nurate modification or nurate / allophanate modification, can also be suitably used. In particular, when using modified products, it is preferable to include one or more urethane-modified and allophanate-modified structures because they tend to exhibit remarkably good wettability.

[0147] Such polyisocyanate residues preferably include bifunctional or multifunctional polyisocyanate residues, and include aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, aromatic polyisocyanate residues, or modified residues thereof. Examples include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and lysine diisocyanate. Examples include residues such as triphenylmethane triisocyanate, tetramethylxylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, or residues of modified forms thereof.

[0148] The content of each residue in the urethane prepolymer (E) may be determined by decomposing it into individual raw materials by methods such as Corish decomposition or alkaline decomposition as needed, and determining the composition ratio. Alternatively, if the charging ratio of each raw material is known, it may be calculated from the charging ratio and the composition of each raw material.

[0149] The urethane prepolymer (E) preferably has a weight-average molecular weight of 3000 or more, as it has a moderate viscosity, good moldability, and a good coating appearance. In particular, it is preferable that the weight-average molecular weight is in the range of 5000 to 200000, which has good fluidity and excellent moldability, more preferably in the range of 8000 to 50000, and most preferably in the range of 15000 to 40000.

[0150] The molecular weight distribution of the urethane prepolymer (E) is usually preferably less than 6.0, but more preferably less than 1.50, even more preferably less than 1.35, and most preferably in the range of 1.05 to less than 1.35. The urethane prepolymer (E) exhibiting a narrow molecular weight distribution that significantly improves the fluidity of the liquid is easily obtained by using a bifunctional polyalkylene oxide (A1) with a low degree of unsaturation, particularly a bifunctional polyalkylene oxide with a remarkably low degree of unsaturation of 0.004 meq / g or less and a remarkably narrow molecular weight distribution of less than 1.039. Examples include polyalkylene oxides obtained using an iminophosphazenium salt catalyst and a Lewis acid catalyst, and the urethane prepolymer (E) is easily obtained and preferred by using the above-mentioned polyalkylene oxide.

[0151] The weight-average molecular weight and molecular weight distribution of the urethane prepolymer (E) can be measured using gel permeation chromatography (GPC) with polystyrene as the standard substance and tetrahydrofuran as the eluent, according to a conventional method. Alternatively, the weight-average molecular weight and molecular weight distribution of the urethane prepolymer (E) may be calculated by measuring the polyol composition (F) using gel permeation chromatography (GPC) and removing peaks such as those of polyol (A).

[0152] The method for producing the urethane prepolymer (E) is not particularly limited, but it can be produced by reacting raw materials containing a polyol and a polyisocyanate in various ways. For example, it can be produced by reacting at a temperature from room temperature to 150°C to allow the urethane formation reaction to proceed. Alternatively, it may be produced using known solvents, catalysts, various additives, etc., and a polyol composition containing the urethane prepolymer may be prepared and left as is, or each component may be removed.

[0153] Furthermore, methods such as polymerizing an active hydrogen compound such as a polyol with a polyisocyanate in excess of hydroxyl groups to directly form a hydroxyl-terminated urethane prepolymer, or a two-step polymerization method in which an active hydrogen compound such as a polyol with a polyisocyanate is polymerized in excess of NCO groups to form an NCO-terminated urethane prepolymer, and then an additional polyol is added and reacted to form a hydroxyl-terminated urethane prepolymer in two steps, can be used.

[0154] While not particularly limited, in a method where a urethane prepolymer with NCO group terminology is formed, and then a polyol is added and reacted to form a urethane prepolymer with hydroxyl group terminology in two steps, a low molecular weight polyol with a high hydroxyl value may be required when converting from NCO group terminology to hydroxyl group terminology. Compared to production by one step polymerization, this method tends to result in more urethane groups, improved cohesiveness, and easier control from light peeling to high adhesion. However, the flexibility and low glass transition temperature characteristics tend to be milder, and this method can be adapted within a range that does not impair the properties.

[0155] Most preferably, the amount of urethane groups can be easily reduced, and significantly better flexibility and low-temperature properties can be easily achieved. This involves polymerizing an active hydrogen compound such as a polyol and a polyisocyanate in a single step with an excess of hydroxyl groups to directly form a urethane prepolymer with hydroxyl group-terminated structures. Alternatively, it is also preferable to polymerize in two or more steps by adding small amounts of the active hydrogen compound such as a polyol or polyisocyanate in divided portions.

[0156] When manufacturing urethane prepolymer (E), it is preferable to dehydrate the polyol and polyisocyanate compounds by vacuum heating or the like before use; however, if the process becomes complicated, they may be used without dehydration.

[0157] (Urethane prepolymer raw material) The urethane prepolymer (E) is not particularly limited, but it is preferable that the urethane prepolymer (E) be obtained from at least the polyol (A) and the polyisocyanate (B).

[0158] The polyol (A) preferred for use in forming the urethane prepolymer (E) is the polyol described in the section on polyol (A) of the polyol composition, and can be suitably used. The preferred polyol is also a polyol of the same type and properties, but it is preferable to include a polyol having two hydroxyl groups in order to easily obtain a urethane-forming composition (H) with good coating properties regardless of conditions. It is particularly preferable to include one or more polyester polyols or polyether polyols in order to significantly improve moisture and heat resistance, and because they are highly versatile and readily available. Most preferably, polyalkylene oxide (A1), which is a type of polyether polyol, is used.

[0159] In particular, the polyol (A) preferred for use in forming the urethane prepolymer (E) is not particularly limited, but it is preferable that it is included in a range where the average number of functional groups of the raw material polyol used for prepolymer formation is less than 2.5, because it tends to exhibit a low thixotropy index (TI value), is less likely to produce gel-like substances or insoluble matter, can differentiate into high solids, and makes it easy to obtain a urethane-forming composition (H) with good coating properties regardless of conditions. More preferably, it is included in a range of 1.90 to 2.20, and most preferably in a range of 1.97 to 2.10, because it is more stable, has a high solid content and appropriate viscosity, has excellent coating properties and productivity, and the resulting cured urethane is more flexible while maintaining cohesive force and exhibits better conformability. Note that the average number of functional groups of the raw material polyol in this embodiment is a value that takes into account the reduction in the actual number of functional groups due to unsaturated monool produced as a by-product during manufacturing when polyalkylene oxide is used.

[0160] The polyol (A) preferred for use in forming the urethane prepolymer (E) is not particularly limited, but it is more preferable to include a polyalkylene oxide (A1) having two hydroxyl groups with an unsaturation degree of less than 0.010 meq / g and a molecular weight in the range of 3000 to 20000 calculated from the hydroxyl value, as this improves cohesiveness and makes it easier to re-peel off. Even more preferable is to include a polyalkylene oxide having two hydroxyl groups with an unsaturation degree of less than 0.004 meq / g and a molecular weight in the range of 4000 to 12000 calculated from the hydroxyl value, as this maintains cohesiveness while easily exhibiting better wettability, flexibility, and low-temperature properties. Most preferably, it is to include a polyalkylene oxide having two hydroxyl groups with an unsaturation degree of less than 0.003 meq / g and a molecular weight in the range of 5500 to 10000 calculated from the hydroxyl value.

[0161] The polyisocyanate (B) preferred for use in forming the urethane prepolymer (E) is preferably one with an average number of functional groups of isocyanate groups of 2.0 or more, but is not particularly limited. Examples of polyisocyanates (B) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, 1,6-hexamethylene diisocyanate, and 4,4'-dicyclohexyl Examples include xylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, and modified isocyanates obtained by reacting these with polyalkylene oxides, as well as mixtures of two or more of these. Furthermore, examples include modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups, uretdione groups, or oxazolidone groups in these isocyanates, as well as condensates such as polymethylene polyphenylene polyisocyanate (polymeric MDI).

[0162] Among these, aliphatic isocyanates, alicyclic isocyanates, or modified versions thereof are preferred because they make it easier to obtain a highly transparent polyol composition (F) with little coloration. More preferably are 1,6-hexamethylene diisocyanate, isophorone diisocyanate, aliphatic isocyanate-containing prepolymers, alicyclic isocyanate-containing prepolymers, or modified versions of these isocyanates containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups, uretdione groups, or oxazolidone groups. These isocyanates may be used individually or in combination of two or more.

[0163] Furthermore, for reasons such as improving cohesiveness and moldability, other polyisocyanates such as trifunctional or monofunctional isocyanate compounds may be reacted in combination with polyisocyanate (B) to form a urethane prepolymer (E). However, it is preferable that the average number of functional groups fave of all polyisocyanates used to form the urethane prepolymer (E) be in the range of 1.90 to 5.00, as this tends to result in a lower thixotropy index (TI value), less formation of gel-like substances and insoluble matter, easier to obtain a urethane-forming composition (H) with good coating properties regardless of conditions, and easier to exhibit better curability. In particular, it is preferable that the average number of functional groups fave of all polyisocyanates used to form the urethane prepolymer (E) be in the range of 2.00 to 3.19, more preferably in the range of 2.00 to 2.79, and most preferably in the range of 2.00 to 2.19, as this reduces the amount of components that seal the ends with monofunctional isocyanates, etc., contained in impurities, making it easier for the prepolymer chain to lengthen and increase cohesiveness, and also makes it easier to improve moldability by achieving a constant viscosity with a high solid content.

[0164] The urethane prepolymer (E) may use active hydrogen compounds different from polyols (A), such as polyamines, polythiols, amino alcohols, and hydroxyacrylates, or isocyanate compounds different from polyisocyanates (B), such as acrylate group-containing monoisocyanates, as raw materials, depending on the desired properties and viscosity. While not particularly limited, when used, it is preferable that the amount of the urethane prepolymer (E) be in the range of 30% by mass or less, more preferably 10% by mass or less, and most preferably in the range of 0.01 to 4% by mass, as this helps maintain the good flexibility and low-temperature properties of the resulting cured urethane.

[0165] Furthermore, monofunctional polyols such as polyoxyethylene glycol alkyl ethers may be used to improve coating properties, but since their cohesive strength tends to decrease, when used, the amount is preferably in the range of 5% by weight or less in the urethane prepolymer (E), more preferably 2% by mass or less, and most preferably in the range of 0.001 to 0.5% by mass.

[0166] <Urethane-forming composition (H)> The urethane-forming composition (H) is a composition comprising the above-mentioned polyol composition (F) and isocyanate compound (G).

[0167] The isocyanate compound (G) is not particularly limited, but may be the same as the polyisocyanate (B), and the preferred isocyanate may also be the same. The isocyanate compound (G) and the polyisocyanate (B) may be the same or different.

[0168] In particular, it is preferable to include an allophanate structure in the isocyanate compound (G) because it results in a urethane-forming composition (H) with good compatibility and higher transparency, making it easier to obtain a urethane cured product that is significantly more flexible, has excellent wettability, and is highly transparent.

[0169] The allophanate structure is not particularly limited, but for example, the structure shown in the following chemical formula (8) is preferably included.

[0170] [ka]

[0171] [In the above chemical formula (8), R1 is a monool residue or a polyol residue.]

[0172] Furthermore, when R1 in the above chemical formula (8) is a polyol residue, there are no particular limitations, but for example, the structure shown in the following chemical formula (9) is preferably included.

[0173] [ka]

[0174] [In the above chemical formula (9), R1 is a polyol residue, which is typically a polyol with an n-valent hydroxyl group removed, and the value of n is usually in the range of 2 to 100.]

[0175] In chemical formula (9), R1 is preferably a monool residue or polyol residue having 1 to 50 carbon atoms, as this exhibits superior compatibility.

[0176] In chemical formula (9), n is preferably an integer in the range of 1 to 2 (where R1 is a monool residue or a diol residue) because it increases mobility and improves wettability.

[0177] Furthermore, the isocyanate compound (G) is more preferably one or more of the following: aromatic isocyanate residues, aliphatic isocyanate residues, alicyclic isocyanate residues, or residues of modified forms of these isocyanates, due to its high versatility and tendency to exhibit good physical properties. More preferably, it is one or more of the following: aliphatic isocyanate residues, alicyclic isocyanate residues, or residues of modified forms of these isocyanates, due to its tendency to exhibit excellent transparency. Most preferably, it is one or more of the following: 1,6-hexamethylene diisocyanate, isophorone diisocyanate, allophanate modified forms of these isocyanates, and / or isocyanurate modified forms.

[0178] In particular, it is preferable to include an allophanate-modified 1,6-hexamethylene diisocyanate because it exhibits high reactivity, good productivity of urethane cured products, and the resulting urethane cured products are significantly more flexible and have excellent wettability.

[0179] When the isocyanate compound (G) is a polyisocyanate, the average number of isocyanate functional groups calculated by gel permeation chromatography (GPC) is preferably in the range of 1.90 to 2.99, more preferably in the range of 1.95 to 2.69, and most preferably in the range of 2.00 to 2.19, in order to maintain cohesive force while exhibiting greater flexibility and wettability.

[0180] When the isocyanate compound (G) is a polyisocyanate, the average number of isocyanate functional groups was calculated using the number-average molecular weight and isocyanate content (isocyanate group concentration) of the polyisocyanate, which were calculated by gel permeation chromatography (GPC), and the following formula. Number of isocyanate functional groups = (number-average molecular weight of polyisocyanate × isocyanate group concentration) / (42 × 100)

[0181] When a plurality of polyisocyanates are used, the average number of isocyanate functional groups of the entire polyisocyanate (G) may be obtained from the amount of each raw material used, the average number of isocyanate functional groups of each raw material, and the number average molecular weight of the polyisocyanate.

[0182] The content of the isocyanate compound (G) in the urethane-forming composition (H) is not particularly limited, but the amount of isocyanate groups derived from the isocyanate compound (G) relative to all hydroxyl groups in the polyol composition (F) is M NCO ) the ratio (M NCO / M OH ) is preferably 0.5 or more and less than 4.0 in terms of molar ratio, more preferably in the range of 0.9 or more and less than 2.5, since this results in better curability and makes it less likely for carbon dioxide foaming marks caused by the reaction between excess NCO groups in the obtained urethane cured product and moisture in the air to occur, and most preferably 1.0 or more and less than 1.7.

[0183] In addition, the mass ratio of the polyol composition (F) to the isocyanate compound (G) (mass of (F) / mass of (G)) in the urethane-forming composition (H) is not particularly limited, but is usually in the range of 99 / 1 to 20 / 80, preferably in the range of 98 / 2 to 50 / 50, and more preferably in the range of 97 / 3 to 85 / 15. When contained in the above ratio, it is easy to obtain a more significantly flexible urethane cured product while maintaining cohesive force, the viscosity increase after mixing the crosslinking agent is gradual, the pot life is prolonged, and handling properties are more likely to be improved.

[0184] The urethane-forming composition (H) may contain the additives and the like exemplified for the polyol composition (F), and may be additionally added as necessary. Preferred types and content ranges of additives are also the same as the preferred types and content ranges of additives for the polyol composition (F). When the type and content of the additives are within this range, good coatability can be obtained when applying the urethane-forming composition (H) with a coater or the like, good pot life and curability can be exhibited, handling can be facilitated, and the obtained urethane cured product also tends to exhibit more remarkable flexibility.

[0185] The preparation of the urethane-forming composition (H) is not particularly limited as long as it can uniformly disperse the prepolymer and raw materials, and can be done using various conventionally known stirring methods. Examples of stirrers include general-purpose stirrers, rotary-orbit mixers, disperser dispersers, dissolvers, kneaders, mixers, laboplast mills, planetary mixers, etc. When the urethane-forming composition (H) is liquid at the stirring temperature, general-purpose stirrers, rotary-orbit mixers, disperser dispersers, and dissolvers are preferably used.

[0186] The viscosity of the urethane-forming composition (H) at 25°C is not particularly limited, but it is preferably in the range of 0.1 to 30 Pa·s, more preferably in the range of 1 to 20 Pa·s, and most preferably in the range of 3 to 15 Pa·s, as it makes it less prone to liquid flow and easier to form uniform thin to thick films. Furthermore, although not particularly limited, the viscosity at 80°C is preferably in the range of 0.05 to 20 Pa·s, more preferably in the range of 0.1 to 15 Pa·s, and most preferably in the range of 0.5 to 10 Pa·s, as it makes it less likely for molding defects such as liquid flow, void formation, and increased thickness at the coating end to occur even under high-temperature conditions such as drying processes. It is also preferable that it is a uniform liquid at 0 to 25°C and does not separate upon standing.

[0187] Furthermore, the organic solvent used in the urethane-forming composition (H) is not particularly limited, and examples of organic solvents that may be included in the polyol composition (F) are those exemplified. The preferred concentration range and solution viscosity are also the same as those of the polyol composition (F). When the concentration range and solution viscosity are within this range, the urethane-forming composition (H) can be easily handled, such as by obtaining good coatability when coating it with a coating machine.

[0188] The urethane-forming composition (H) contains a triazole derivative (C) and a hindered phenol compound (D), which results in a longer pot life and excellent handling properties. Preferably, the non-volatile content is 80% by mass or more, and the time required for a 20% viscosity increase is 4 hours or more, and such properties are easily obtained. In particular, it is preferable that the urethane-forming composition (H) has a non-volatile content of 80% by weight or more, a ketoenol tautomer compound content in the range of 0.001 to 2.0% by mass, and the time required for a 20% viscosity increase is 15 hours or more, and such properties are easily obtained. Even more preferably, the non-volatile content is 90% by mass or more, a ketoenol tautomer compound content in the range of 0.003 to 0.5% by mass, and the time required for a 20% viscosity increase is 24 hours or more, and such properties are easily obtained.

[0189] <Cured urethane product (I)> The urethane cured product (I) is a reaction product of the urethane-forming composition (H), and includes a reaction product of an active hydrogen compound such as a polyol (A) or urethane prepolymer (E) in the urethane-forming composition (H) and an isocyanate compound (G).

[0190] The urethane cured product (I) is obtained by reacting the urethane-forming composition (H) by various methods and allowing it to harden (solidify). The method for producing these urethane cured products (I) is not particularly limited. For example, the urethane-forming composition (H) can be produced by carrying out a urethane reaction and a urea reaction at room temperature or a high temperature of 150°C or lower, in the presence of a urethane catalyst, antioxidant, stabilizer, filler, crosslinking agent, and other additives as needed.

[0191] Furthermore, in order to achieve good curing properties, the process may include steps for activation at high temperatures or removal of solvents as needed. The applications of urethane cured product (I) are not particularly limited and can be used in any application where ordinary polyurethane is used, but it is particularly suitable for applications where mechanical properties and adhesive properties are required. Specifically, examples of suitable applications include sealing materials for construction and civil engineering, adhesives such as elastic adhesives for construction, gum tape and surface protective films, various adhesives such as those for optical applications, release agents, vibration damping materials, paints, elastomers, waterproof coating materials, flooring materials, plasticizers, flexible polyurethane foam, semi-rigid polyurethane foam, and rigid polyurethane foam.

[0192] Among these, polyurethane is particularly preferred for use as a sealant, paint, adhesive, or bonding agent, given the strong demands for its adhesive properties, stain resistance, low VOC content, cold resistance, and flexibility, as well as its environmental adaptability, workability, coating properties, and conformability to the substrate.

[0193] <urethane sheet> The urethane-forming composition (H) exhibits high solid differentiation and remarkably excellent coating properties, allowing for the production of urethane-cured sheets (I) with uniform thickness ranging from thin films to thicker materials.

[0194] In the case of urethane sheets, there are no particular restrictions on the thickness, but the thickness of the coating film is preferably in the range of 0.1 to 3000 μm, and more preferably in the range of 5 to 1500 μm, because the appearance of the coating film is particularly good. In particular, a thickness of 10 to 700 μm is preferable because it is easy to obtain a urethane-forming composition (H) with a high solid content and appropriate viscosity, exhibits remarkably good curability uniformly even up to high-thickness products which tend to require strict curing conditions, and makes it easy to obtain a sheet of characteristic urethane cured product (I) that does not easily leave adhesive residue on the fingers when molded at such thicknesses.

[0195] Furthermore, to facilitate application to various uses, the urethane sheet may have a configuration of two or more layers, comprising at least one base material and a urethane cured product (I) layer provided on that base material; a configuration of three or more layers including a release film layer in addition to at least one base material and a urethane cured product (I) layer provided on that base material; a configuration of three layers having a urethane cured product (I) layer on both sides of the base material; or a configuration of five or more layers including a release film layer in addition to the urethane cured product (I) layer. Additionally, the adhesive layer may be encapsulated to form a sheet.

[0196] <Urethane adhesive> Because the cured urethane product (I) exhibits excellent re-peelability and remarkably good resistance to moisture and heat, it can be particularly suitably used as a urethane adhesive when included in the product. Furthermore, it is easy to form from raw materials with high solid content, and tends to result in a low-VOC product with a small environmental impact, which is preferable.

[0197] The urethane adhesive of the present invention exhibits remarkably good moisture and heat resistance, even when using polyether polyols, polyester polyols, and especially polyalkylene oxides. In addition to moisture and heat resistance, it easily exhibits good flexibility and adhesive properties, as well as impact resistance from low to high temperatures. Furthermore, because the adhesive-forming composition has an appropriate viscosity and is easily obtained with a uniform composition, it tends to have excellent transparency.

[0198] The urethane adhesive of the present invention has the characteristic of not degrading easily after standing in a high-temperature, high-humidity environment and easily retaining its cohesive force. Therefore, although not particularly limited, it is preferable that it be possible to peel off the interface after standing for 120 hours at 85°C and 85%RH conditions after bonding to a glass substrate, and it easily exhibits such good re-peelability. Furthermore, the urethane adhesive of the present invention easily achieves a characteristic balance between good humidity and heat resistance and good flexibility, and its elastic modulus at a frequency of 1 Hz and 25°C is 2 × 10⁻⁶. 4 Pa~3×10 5 It is preferably Pa or less, and more preferably 3 × 10 4 Pa~2×10 5 The range is Pa, most preferably 5 × 10 4 Pa~1.5×105 It is in the Pa range and is easily obtained while maintaining good resistance to moisture and heat. The modulus of elasticity at a frequency of 1 Hz and 25°C is 2 × 10⁻⁶. 4 Pa~3×10 5 Within the Pa range, the adhesive is more easily deformed while maintaining cohesive force, which is preferable because it allows it to conform to uneven surfaces of the adherend while exhibiting adhesive properties such as interfacial peelability and adhesive strength, thus suppressing the generation of air bubbles.

[0199] In this invention, the modulus of elasticity at 25°C is measured using a Rheogel E-4000 dynamic viscoelasticity measuring instrument manufactured by UBM, under conditions of a measurement temperature of -100°C to 200°C, a heating rate of 2°C / min, a frequency of 1 Hz, and shear mode, and represents the value of the storage modulus of elasticity G' at each temperature.

[0200] The glass transition temperature of the urethane adhesive is not particularly limited, but is preferably in the range of -30°C or lower. More preferably, it is in the range of -80°C to -50°C. A glass transition temperature of -30°C or lower is preferable because it does not leave adhesive residue or reduce heat resistance, and peeling and cracking are suppressed when dropped even at low temperatures, and high adhesion at low temperatures can be expected.

[0201] In this invention, the glass transition temperature was measured using a dynamic viscoelasticity measuring device, the Rheogel E-4000 manufactured by UBM, under shear mode conditions with a measurement temperature of -100°C to 200°C, a heating rate of 2°C / min, a frequency of 1 Hz, and the temperature at which the peak value of tanδ, which is the ratio of the loss modulus G'' to the storage modulus G', was obtained was evaluated as the glass transition temperature.

[0202] The adhesive strength of the urethane adhesive to alkali-free glass, as measured by the JIS Z0237 method, is not particularly limited, but is preferably in the range of 0.1 N / 25 mm to less than 30 N / 25 mm, and more preferably in the range of 0.5 N / 25 mm to less than 20 N / 25 mm, and particularly preferably in the range of 1 N / 25 mm to less than 10 N / 25 mm, as this allows for moderate adhesive strength while exhibiting remarkably excellent re-peelability. Furthermore, although not particularly limited, from the viewpoint of re-peelability, interfacial peeling is preferred.

[0203] The adhesive strength of the urethane adhesive was measured using Corning Eagle XG, a 0.7 mm thick alkali-free glass, in accordance with JIS Z0237. Specifically, a 38 μm thick PET film, Toray Lumirror S-10, was backed onto the adhesive surface, cut to a width of 25 mm, and roll-pressed to prepare a test specimen in accordance with JIS Z0237. Using an Orientec RTG-1210 tensile testing machine, the adhesive strength was measured in accordance with JIS Z0237 under conditions of 23°C, 50% RH, a peel angle of 180°, and a tensile speed of 300 mm / min. The 180° peel adhesive strength (N / 25 mm) was defined as the adhesive strength.

[0204] The haze of the urethane adhesive, as measured by the JIS K7136 method, is not particularly limited, but preferably less than 2% haze at a thickness of 90 μm, more preferably less than 0.4%, and most preferably less than 0.2%. A haze of less than 1% at a thickness of 90 μm is preferable because it provides high transparency, excellent visibility, and a good appearance. Although not particularly limited, when used in optical applications such as optical adhesive sheets, a haze of less than 1% at a thickness of 80 μm is preferable. Such adhesives with a haze of less than 1% at a thickness of 80 μm are preferably manufactured under conditions where the molar ratio ([total NCO groups] / [total OH groups]) of the total amount of NCO groups to the total amount of active hydrogen groups constituting the adhesive-forming composition is in the range of 0.9 to less than 1.3.

[0205] In this invention, Haze is the value excluding the substrate used for measurement. Specifically, if the Haze of the PMMA substrate is 0.2% and the Haze of the two-layer structure of PMMA and adhesive is 0.5%, then the Haze of the adhesive is assumed to be 0.5 - 0.2 = 0.3%.

[0206] The urethane adhesive is less prone to whitening after being removed from the humid and heat-resistant environment, demonstrating good resistance to humid and heat-induced whitening. Specifically, after being kept at 85°C and 85%RH for 5 days and then placed in a constant temperature room at 25°C and 50%RH, the change in haze value tends to be less than 1%.

[0207] Urethane adhesives exhibit good moisture and heat resistance regardless of polyol type or thickness. By utilizing this characteristic, they can maintain flexibility at room temperature and elasticity even at high temperatures, offering excellent vibration absorption, adhesion, low-temperature properties, and tackiness. They can also be expected to conform to printing steps, have impact resistance, and maintain adhesion from low to high temperatures.

[0208] The urethane adhesive can be provided in any shape, such as film, sheet, plate, or block.

[0209] <Urethane adhesive sheet> The urethane adhesive sheet of the present invention is characterized by having at least one substrate and an adhesive layer provided on that substrate, wherein the adhesive layer contains the urethane cured product (I) of the present invention.

[0210] Examples of substrates used in the urethane adhesive sheet of the present invention include release films and core materials. Examples of such release films include PET, PP, TPX, and films of these materials that have been treated with silicone, fluorine, etc. Examples of commercially available release PETs include Toyobo's Purex A31, A33, A35, and A43. Examples of core materials include nonwoven fabrics, PET films, and PP films.

[0211] The lamination structure of the urethane adhesive sheet of the present invention is not particularly limited, but examples include a three-layer substrate-less adhesive sheet with both sides sandwiched between release PET, and a five-layer double-sided adhesive sheet with a core material in the adhesive layer.

[0212] The thickness of the adhesive layer in the urethane adhesive sheet of the present invention is not particularly limited, but is preferably in the range of 0.1 μm to 3000 μm, more preferably in the range of 1 μm to 1500 μm, and most preferably in the range of 10 μm to 700 μm. In particular, for adhesive sheets that need to conform to curved surfaces, uneven surfaces, folds, etc., a range of 90 μm to 700 μm is preferred.

[0213] The shape of the urethane adhesive sheet using the urethane adhesive can be any desired shape. While not particularly limited, it may be in roll form or cut into sheets.

[0214] The method for manufacturing a urethane adhesive sheet is not particularly limited, but for example, a method can be used in which a component containing the polyol composition (F) of the present invention and a component containing a crosslinking agent are mixed in a predetermined ratio to form a urethane-forming composition, and then coated using, for example, a roll coater, gravure coater, microgravure coater, reverse coater, air knife coater, comma coater, die coater, etc. When using these coating methods, it is desirable to apply the urethane-forming composition to one or both sides of the substrate, and then degas, heat, and dry as necessary.

[0215] As for heating methods, commonly used methods such as hot air drying, hot roll drying, and infrared irradiation can be used. The drying temperature is not particularly limited, but is usually in the range of 50 to 200°C, more preferably 70 to 150°C, and even more preferably in the range of 110 to 150°C, as this temperature makes it less prone to degradation even under high temperature conditions and tends to exhibit characteristically high curability, thus allowing for the production of adhesive sheets with good productivity at high temperatures. When a thermoplastic resin is used as the substrate, it is desirable that the drying temperature be below its melting point. A drying temperature in the range of 50 to 200°C is preferable because it is less likely to cause degradation of the substrate or change in color.

[0216] The heating time is not particularly limited and can be arbitrarily selected depending on the thickness, amount of catalyst, etc., but is usually 10 seconds to less than 30 minutes, preferably 1 minute to less than 15 minutes. In particular, the urethane-forming composition using the polyol composition of the present invention exhibits remarkably good moisture and heat resistance and high curability regardless of conditions such as high temperature and high thickness, making it easier to speed up the coating line even at high thicknesses, and is more preferable because it takes advantage of its characteristics by being heat-cured with an adhesive layer thickness of 90 μm or more in 3 minutes to less than 8 minutes, resulting in excellent productivity, and is easy to cure under such conditions.

[0217] The applications of urethane adhesives and urethane adhesive sheets are not particularly limited and include, for example, tapes, labels, seals, cosmetic sheets, anti-slip sheets, and double-sided adhesive tapes. Specifically, examples include packaging tapes, label tapes, masking tapes, and kraft tapes for packaging, office and household use; medical tapes such as bandages; biomedical tapes such as those for skin application; wallpaper tapes, foam tapes, and building elastic adhesives; tapes for electronic materials used in personal computers, televisions, mobile phones, automobiles, solar cells, semiconductors, and other home appliances; optical adhesive sheets used for adhesion of liquid crystal displays and touch panels; surface protection tapes, waterproof tapes, conductive tapes, and heat dissipation tapes used in shipping and manufacturing processes. These can be suitably used in these applications.

[0218] The urethane adhesive and adhesive sheet of the present invention can be suitably used in applications requiring particularly high humidity and heat resistance, or applications requiring high thickness and conformability, such as substrates and semiconductors for electronic devices, automotive components, and biomedical applications; applications requiring adhesion to curved and uneven surfaces and compatibility with humid and hot environments; applications requiring conformability to bending of foldable materials, etc., and conformability to printed steps in touch panels, etc., where use in humid and hot environments is anticipated. Specifically, it can be used in optical applications such as touch panels, electrical and electronic component applications, automotive applications, biomedical tapes, and various binding applications. Specific applications are not limited to these, but examples include optical adhesive sheets used in electronic devices such as smartphones, tablet PCs, and laptop computers, and protective tapes for electronic components. Among these, it can be suitably used for adhesion of various films inside the above-mentioned electronic devices.

[0219] Specific electronic and optical applications of the adhesive sheet for electronic and optical use are not particularly limited, and examples include adhesive sheets used for adhesion of touch panels and displays of mobile phones, smartphones, tablets, foldable terminals, car navigation systems, personal computers, ticket vending machines, etc., and surrounding functional films such as ITO films, silver meshes, copper meshes, polarizing plates, and semiconductors. The operation method of the touch panel is not particularly limited, and the adhesive sheet can be suitably used for resistive film type, capacitive type, optical type, ultrasonic type, electromagnetic induction type, and the like. [Examples]

[0220] Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not to be construed as being limited by the following examples unless it exceeds the gist of the present invention. The raw materials used in the following examples and comparative examples and the evaluation methods are as described below.

[0221] (Raw Material 1) Polyol (A) and polyalkylene oxide (A1) used in Examples and Comparative Examples Properties of polyalkylene oxides and the like used in Examples and Comparative Examples were determined by the following methods.

[0222] <Hydroxyl Value and Number Average Molecular Weight of Polyol> The hydroxyl value of the polyol was measured in accordance with the method described in JIS-K1557-1. The number average molecular weight of the polyol was calculated from the hydroxyl value of the polyol and the number of hydroxyl groups in one molecule of the polyol. <GPC Number Average Molecular Weight, Weight Average Molecular Weight, Molecular Weight Distribution> GPC measurement was performed on polyols, polyol compositions, or urethane-forming compositions under standard conditions using THF as a solvent, and the number average molecular weight and weight average molecular weight in terms of standard polystyrene were evaluated. A sample vial was filled with 10 mg of solids and 10 ml of THF, and allowed to stand overnight to dissolve. The sample was then filtered through a PTFE cartridge filter (0.5 μm) to obtain the sample. An RI detector RI8020 was used as the detector, and two TSKgelGMR-HHRL columns were used in series as the measurement column (both manufactured by Tosoh Corporation). Measurements were performed under the following conditions: column temperature 40°C, flow rate 1.0 ml / min, and solvent THF. Number-average molecular weight and weight-average molecular weight were analyzed using a cubic approximation calibration curve with standard polystyrene manufactured by Tosoh Corporation. The ratio of these two values, Mw / Mn, was defined as the molecular weight distribution. A Tosoh HLC-8320GPC was used for measurement, and a Tosoh HLC-8320GPC-ECOSEC-WorkStation was used for analysis. <Degree of unsaturation and average number of functional groups of polyalkylene oxide (A1)> The degree of unsaturation of polyalkylene oxide (A1) was measured using the NMR method described in Polymer Science, 1993, 50, 2, 121-126, with 800 scans. Furthermore, this degree of unsaturation was converted to the amount of monool with an unsaturated group at one end, and the average number of functional groups of hydroxyl groups was calculated. In addition, the degree of unsaturation in the urethane prepolymer and urethane-forming composition was calculated from the degree of unsaturation and quantitative ratio of each polyalkylene oxide used, since the raw materials were known. <Ethylene oxide content (wt%)> Nuclear magnetic resonance (NMR) spectroscopy was used to measure 1H NMR using deuterated chloroform containing tetramethylsilane as the deuterated solvent. The ethylene oxide content in the polyol was calculated from the integrated values ​​in the range of 0.8–1.5 ppm (propylene oxide chain) and the integrated values ​​in the range of 3.2–3.9 ppm (propylene oxide chain and ethylene oxide chain).

[0223] (Raw material 1-1) Polyol (A) used in the example and comparative example. Polyalkylene oxides (A1-1), (A1-2): Polypropylene oxides obtained by adding thoroughly dehydrated propylene oxide to a bifunctional polyoxypropylene glycol with a molecular weight of 400, using an imino group-containing phosphatazenium salt (IPZ) catalyst and triisopropoxyaluminum to perform sufficient dehydration and solvent removal. Polyalkylene oxide (A1-3): A commercially available trifunctional polyalkylene oxide with a relatively low degree of unsaturation, an ethylene oxide added to the terminal, and containing a glycerol initiator residue; polyoxyethylene propylene oxide. Polyalkylene oxide (A1-4): A trifunctional polyalkylene oxide having a glycerol initiator residue, produced by adding propylene oxide using a potassium hydroxide catalyst by a conventional method. Polyol (A2): Commercially available polyester polyol (Nipporan 4009, manufactured by Tosoh Corporation) The polyol (A) and polyalkylene oxide (A1) used in the examples and comparative examples were both used after heating and vacuum dehydration. Furthermore, polyalkylene oxides prepared using or in combination with a catalyst were used after the catalyst was removed.

[0224] The properties of polyol (A) are shown in Table 1.

[0225] [Table 1]

[0226] (Raw material 2) Triazole derivative (C), other compounds (CC) Triazole derivative (C1): 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (BASF Tinuvin 571) Triazole derivative (C2): Triazole derivative C2: C7-C9 alkyl ester of 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxybenzenepropionic acid (BASF Tinuvin 99-2) Triazole derivative (C3): 2-(2'-hydroxy-3',5'-bis(methylbenzyl)phenol)benzotriazole (BASF Tinuvin 234) Triazole without long-chain alkyl ester Other compound (CC1): 1,2-dimethylimidazole Other compound (CC2): N,N'-dimethylpiperazine

[0227] (Raw material 3) Hindered phenol compounds (D) with a molecular weight of 250 or more and less than 1000, and other phenol compounds (DC) Hindered phenol compound (D1): Isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, Irganox 1135 Hindered phenol compound (D2): Stearyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, Irganox 1076 Other phenolic compounds (DC1): 4-methyl-2,6-di-tert-butylphenol, BHT (molecular weight 220) Other phenolic compounds (DC2): [3-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]propyl] 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, Irganox 1010 (molecular weight 1178)

[0228] (Raw material 4) Additive Ketoenol tautomer compounds: Acetylacetone Urethane catalyst: Iron trisacetylacetonate (Fe(acac)3) (Raw material 5) Isocyanate compounds (B) and (F) used in the examples and comparative examples. Isocyanate (B1): 1,6-Hexamethylene diisocyanate (HDI) Isocyanate (B2): Isophorone diisocyanate (IPDI) Isocyanate (F1): Allophanate-modified bifunctional HDI-based crosslinking agent (Tosoh Corporation's Coronate 2770)

[0229] (Preparation of polyol composition (F)) A 10% MEK masterbatch of polyol (A) and iron trisacetylacetonate (Fe(acac)3) as a urethane catalyst was added to a sample bottle in the amount indicated in the table based on solid content, mixed, and then dehydrated and desolvent-removed.

[0230] After cooling, a triazole derivative (C), a hindered phenol compound (D), and acetylacetone were added as needed. Subsequently, the mixture was dissolved and dispersed by heating to approximately 50°C as needed, to obtain a polyol composition (F).

[0231] (Preparation of urethane prepolymer (E) and polyol composition (F) containing urethane prepolymer) A four-necked round-bottom flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer was used to add polyol (A) and a 10% MEK masterbatch of iron trisacetylacetonate (Fe(acac)3) as a urethane catalyst, in amounts corresponding to the amounts shown in the table based on solid content. Vacuum dehydration and solvent removal were then performed at 100°C for 2 hours.

[0232] After cooling, a predetermined amount of isocyanate compound (B1) was added, and the reaction was carried out by raising the temperature to 70°C under nitrogen. The amount of NCO groups in the reactor contents was tracked using an infrared spectrophotometer, and the completion of the reaction was confirmed by the disappearance of NCO groups, confirming the formation of OH-terminated urethane prepolymer (E).

[0233] After cooling, a triazole derivative (C), a hindered phenol compound (D), and, if necessary, a polyol (A) or acetylacetone were added. The mixture was then heated to approximately 50°C and mixed to dissolve and disperse the components, resulting in a polyol composition (F). The polyol composition was also confirmed by GPC (Geochemical Propagation) if necessary.

[0234] (Preparation of urethane-forming composition (H) and urethane cured product (I)) In the examples and comparative examples, predetermined amounts of each raw material (polyol composition (F), isocyanate (G)) were placed in 30 ml sample bottles, and the mixture was stirred and degassed at room temperature using a pencil mixer to obtain a urethane-forming composition (H).

[0235] (Performance evaluation) A urethane-forming composition (H) was coated onto a 38 μm thick PET film using a baker-type applicator to achieve a high thickness of 120 μm after drying. The mixture was then held in an explosion-proof oven set to 140°C for 7 minutes to remove volatile components and allow the curing reaction to proceed, forming a cured urethane product (I) on the PET film. A release PET sheet was then laminated to form a three-layer sheet structure. Finally, the sheet was left to stand for one week at 23°C and 50% relative humidity to obtain a polyurethane sheet.

[0236] In that process, the performance of the polyol composition (F) and the urethane-forming composition (H) was evaluated according to the following evaluation criteria.

[0237] <Curing properties at high temperatures and high thicknesses> ◎(Curing performance passed): The urethane cured product has no odor immediately after being removed from the oven, exhibits high cohesiveness including in thicker sections, and leaves no adhesive residue on the fingers when touched. ○ (Curing performance passed): The cured urethane material had no odor immediately after being removed from the oven, and although some residue was present when touched, no adhesive residue remained on the fingers after curing at room temperature for one week. × (Curing performance failure): The cured urethane has an odor immediately after being removed from the oven and shows slight signs of deterioration, or when touched after curing at room temperature for one week after being removed from the oven, a small amount of adhesive remains on the finger in some areas (judged to be a decrease in curing performance due to thermal degradation during curing). Products marked with ◎ or ○ were judged to have cured without thermal degradation even when heated and cured under high temperature and high thickness conditions, and to exhibit remarkably good curability regardless of the conditions, thus passing this item.

[0238] <Heat and moisture resistance> The polyurethane sheet was peeled off its PET release layer, bonded to a glass substrate, and left to stand for 120 hours in a constant temperature and humidity chamber at 85°C and 85%RH. After removal, it was left to stand for 2 days at 23°C and 50%RH to stabilize the moisture content. The sheet was then peeled from the glass substrate using a tensile testing machine at a rate of 300 mm / min and evaluated according to the following criteria. ◎(Humidity and heat resistance pass): The adhesive is odorless immediately after being removed from a high temperature and high humidity environment, and after standing at 23℃ and 50%RH, a tensile test shows an adhesive strength of 0.5N / 25mm or more and complete interface peeling is achieved. ○ (Humidity and heat resistance pass): A slight odor was present immediately after removal from a high-temperature, high-humidity environment, but after standing at 23°C and 50% RH, a tensile test showed complete interface delamination. Alternatively, the adhesive had no odor immediately after removal from a high-temperature, high-humidity environment, and after standing at 23°C and 50% RH, a tensile test showed a bonding strength of less than 0.5 N / 25 mm and complete interface delamination. (Judged to have remarkably high practical humidity and heat resistance.) × (Failure to meet moisture and heat resistance standards): Cases other than ◎ and ○ (If a strong odor is present immediately after removal from a high-temperature, high-humidity environment, or if some / all of the material fails to cohere during a tensile test, it is determined that the cohesion strength has decreased due to deterioration and that the material does not have high resistance to humidity and heat.) Products marked with ◎ or ○ showed no thermal degradation even under harsh high-temperature and high-humidity conditions of 85°C and 85%RH for 120 hours, and were judged to exhibit remarkably good humidity and heat resistance regardless of the conditions, thus passing this item. Products marked with ◎ in particular were judged to be especially suitable as intermediate release adhesives, which are particularly difficult to achieve in combination with high humidity and heat resistance. Products that passed both the curing properties at high temperatures and high thicknesses, and the moisture and heat resistance and durability tests were deemed acceptable. These products showed no moisture and heat degradation even under harsh high temperature and high humidity conditions, and were judged to exhibit remarkably good moisture and heat resistance and curing properties regardless of the conditions, thus passing the test.

[0239] <Flexibility> In the performance evaluation section above, a urethane sheet was fabricated using double-sided release PET. Only the resulting cured urethane was extracted, and its dynamic viscoelasticity was measured in shear mode. The modulus of elasticity (G') at 25°C was evaluated according to the following criteria. This was used as an indicator of step-following ability and bending-following ability. ◎(Flexibility passed): 3.0×10 4 Pa or higher, 2.0×10 5Pa·s or less. ○ (flexibility qualified): 2.0×10 5 Pa·s more than, 4.0×10 5 Pa·s or less. △ (no advantage in flexibility): 4.0×10 5 Pa·s more than. * In this evaluation, there were no test specimens with an elastic modulus outside the above range. Those that passed both curability at high temperature and high thickness and moist-heat resistance durability, and also passed this evaluation are judged to be capable of achieving both remarkably good flexibility and remarkably good moist-heat resistance durability, which are normally in a trade-off relationship, and are judged to be particularly characteristic flexible urethane cured products with high moist-heat resistance that can be expected to have followability etc. in addition to moist-heat resistance.

[0240] <Formability at High Thickness> (Evaluated in a system containing a prepolymer) ◎ (high-thickness formability qualified): When coated at a dry thickness of 500 µm, thickness unevenness due to flow during curing is within 10%, and no adhesive remains on the finger when touching the urethane cured product immediately after heat curing taken out of the oven. ○ (high-thickness formability qualified): When coated at a dry thickness of 500 µm, thickness unevenness due to flow during curing is more than 10% and within 20%, and no adhesive remains on the finger when touching the urethane cured product immediately after heat curing taken out of the oven. × (no advantage in high-thickness formability): When coated at a dry thickness of 500 µm, thickness unevenness due to flow during curing is more than 20%, or adhesive remains on the finger when touching the urethane cured product immediately after heat curing taken out of the oven. It is judged that coating defects are likely to occur, liquid flow easily occurs at high temperature during curing, or thermal degradation and curing defects easily occur at a thickness of 500 µm.

[0241] <High Solid Content Conversion> ◎ (low VOC qualified): Non-volatile content is 99% or more, and the viscosity at 25°C is in the range of 3 to 15 Pa·s ○ (low VOC qualified): Excluding those with ◎ judgment, non-volatile content is 80% or more, and the viscosity at 25°C is in the range of 0.5 to 20 Pa·s × (no advantage): Non-volatile content is less than 80%, or the non-volatile content is 80% or more but the viscosity at 25°C is outside the range of 0.5 to 20 Pa·s. It is judged that low VOC conversion is difficult because it does not have a constant viscosity at high solid content. The polyol composition that passed both the high-temperature and high-thickness curing properties and the moisture-heat resistance test was judged to be a polyol composition that has a high solid content, appropriate viscosity, and excellent high-thickness moldability, and is characterized by its ability to exhibit high-thickness moldability and moisture-heat resistance.

[0242] <Pot life> ◎(Good pot life): After mixing with the hardener, the viscosity increase rate after 48 hours is 20% or less. ○ (Good pot life): After mixing with the hardener, the viscosity increase rate after 10 hours is 20% or less, and the viscosity increase rate after 48 hours is more than 20%. △ (Usable): When mixed with a hardener, the viscosity increase rate after 4 hours is 20% or less, and the viscosity increase rate after 10 hours is more than 20%. △× (No special features): After mixing with a hardener, the viscosity increase rate after 4 hours exceeds 20%. Mixing and standing were performed under 23°C conditions, and viscosity was measured at 25°C using a B-type viscometer.

[0243] <Adhesive properties> ◎(Good adhesion): Adhesion strength of 0.5~20N / 25mm, holding power for 24 hours or more with displacement of less than 1mm. ○ (Good adhesion): Adhesion is between ◎ and ×, and holding power is 100 minutes or more. △(Other): Adhesion less than 0.1 N / 25 mm or greater than 30 N / 25 mm, or holding power less than 100 minutes. Not suitable for light peeling applications or non-re-peelable, high-adhesion applications, or judged to have insufficient cohesive force. In addition to moisture and heat resistance, a polyol composition (F) that meets the requirements for pot life and adhesive properties was judged to have a characteristically long pot life and practical, appropriate adhesive properties, and was determined to be a polyol composition (F) that exhibits the aforementioned properties while having excellent productivity, particularly suitable for the continuous production of urethane cured products.

[0244] (Example 1) In Example 1, 85 parts by weight of polyol (A1-1), 15 parts by weight of polyol (A1-3), and a 10% MEK masterbatch of iron trisacetylacetonate (Fe(acac)3) as a urethane catalyst were added to a sample bottle in the amount indicated in the table on a solid content basis. After thorough mixing, dehydration and solvent removal were performed using an evaporator.

[0245] After cooling, 0.03 parts by weight of a triazole derivative (C1), 0.3 parts by weight of a hindered phenol compound (D1), and 0.3 parts by weight of acetylacetone were added, and the mixture was heated to approximately 50°C and mixed to dissolve and disperse, thereby obtaining a polyol composition (F1). The polyol composition (F1) was a uniformly transparent liquid at room temperature, exhibited good compatibility, and was expected to produce a urethane cured product with good transparency. Furthermore, the non-volatile content of the polyol composition (F1) was remarkably high at 99.7% by weight, suggesting low VOCs. However, because it did not contain a urethane prepolymer (E), it exhibited significant flow during curing at high thicknesses.

[0246] The obtained polyol composition (F1) and isocyanate compound (G1) are used to determine the amount of hydroxyl groups derived from (F1) (M OH ) and the amount of isocyanate groups derived from (G1) (M NCO ) is the molar ratio of (G1) M NCO / ((F1) M OH The mixture was prepared using a pencil mixer so that the ratio of the components was 1.15, and then mixed and degassed using a rotary-orbit mixer to obtain a urethane-forming composition (H1).

[0247] A urethane-forming composition (H1) was coated onto a 38 μm thick PET film using a baker-type applicator to achieve a high thickness of 120 μm after drying. The mixture was then held in an explosion-proof oven set to 140°C for 7 minutes to remove volatile components and allow the curing reaction to proceed, forming a cured urethane product (I1) on the PET film. A release PET sheet was then laminated to create a three-layer sheet structure. Finally, the sheet was left to stand for one week at 23°C and 50% relative humidity to obtain a polyurethane sheet.

[0248] Table 2 shows the composition and evaluation results. The urethane-forming composition (H1) contains a triazole derivative (C1) and a hindered phenol compound (D1). As a result, it exhibits excellent curability at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes to remove volatile components. Despite the use of a small amount of ketoenol tautomer compound, the viscosity increase rate after 48 hours is less than 20%, demonstrating remarkably excellent pot life. The resulting urethane cured product (I1) coating film exhibits remarkably excellent resistance to moisture and heat.

[0249] Furthermore, the resulting urethane cured product (I1) coating film contains a polyalkylene oxide structure mainly composed of bifunctional groups, and because it has few unsaturated monools sealing the ends, it easily forms a flexible and loose network with few defects, and its storage modulus at 25°C is 1.3 × 10⁻⁶. 5 This urethane cured product (I1) exhibits remarkable flexibility with Pa, and in addition to its resistance to moisture and heat, it is expected to have good conformability to deformation such as bending, movement, and steps. Furthermore, its glass transition temperature is remarkably low at -56°C, demonstrating excellent low-temperature characteristics and promising good cold resistance, including resistance to impact peeling at low temperatures.

[0250] (Examples 2-6) To observe synergistic effects with respect to Example 1, polyol compositions (F2) to (F6) were prepared by changing the amount of triazole derivative (C1) and hindered phenol compound (D1) added and the mixing mass ratio. Similarly, urethane-forming compositions (H2) to (H6) and urethane sheets containing urethane cured products (I2) to (I6) on PET films were prepared.

[0251] Table 2 shows the composition and evaluation results. In all of the additive amounts and mixing mass ratios in Examples 2 to 6, volatile matter removal and curing reaction were performed in an explosion-proof oven at 140°C for 7 minutes, demonstrating excellent curing performance at high temperatures and thicknesses. The resulting urethane cured coatings (I2) to (I6) exhibited remarkably superior moisture and heat resistance. Furthermore, the resulting urethane cured coatings (I2) to (I6), similar to Example 1, contain a polyalkylene oxide structure mainly composed of bifunctional compounds, and because they contain few unsaturated monools that seal the ends, they easily form a flexible and loose network with few defects, and their storage modulus at 25°C is 2.0 × 10⁻⁶. 5 The urethane cured products (I2) to (I6) were remarkably flexible, with a Pa of less than 1.

[0252] (Example 7) A urethane sheet containing a polyol composition (F7), a urethane-forming composition (H7), and a cured urethane product (I7) on a PET film was prepared under the same conditions as in Example 2, except that the polyol (A1-1) with a molecular weight of 5400 was changed to a polyol (A1-2) with a molecular weight of 8500, and the amount of polyfunctional polyol (A1-3) added was changed from 15 parts by weight to 25 parts by weight.

[0253] Table 2 shows the composition and evaluation results. Even with the composition of Example 7, the curing reaction at high temperature and thickness was excellent when volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes. The resulting urethane cured product (I7) coating film exhibited remarkably excellent resistance to moisture and heat. Furthermore, the resulting urethane cured product (I7) coating film contained a polyalkylene oxide structure mainly composed of bifunctional groups, similar to Example 2, and had few unsaturated monools sealing the ends, making it easy to form a flexible and loose network with few defects. The storage modulus at 25°C was 2.0 × 10⁻⁶. 5 The cured urethane product (I7) was remarkably flexible, with a Pa rating of less than 1.

[0254] (Example 8) Compared to Example 2, the composition of polyol (A1-1) with low unsaturation and polyfunctional polyol (A1-3) was changed to only polyfunctional polyalkylene oxide (A1-3), which has high unsaturation and contains a large amount of monool, and a polyol composition (F8), a urethane-forming composition (H8), and a urethane sheet including a cured urethane product (I8) on a PET film were produced under the same conditions, except that the substantial number of functional groups in consideration of monool was set to approximately the same level as 2.25. Table 2 shows the composition and evaluation results. Compared to Example 2, although the substantial number of functional groups was at the same level, there was a slight curing delay tendency that is considered to be caused by the increase in relatively low-molecular-weight components. However, even under high temperature and large thickness conditions when devolatilization and curing reaction were performed in an explosion-proof oven at 140°C for 7 minutes, somewhat good curability was exhibited. The coating film of the obtained cured urethane product (I8), although slightly lower in performance than that of Example 2, was remarkably excellent in moist-heat resistance durability. Additionally, since it is based on trifunctional polyol (A1-4, although flexibility was slightly lowered compared to Example 2, good flexibility was exhibited.

[0255] (Example 9) Compared to Example 2, a polyol composition (F9), a urethane-forming composition (H9), and a urethane sheet including a cured urethane product (I9) on a PET film were produced under the same conditions, except that the polyol (A1) having a polyalkylene oxide structure with a molecular weight of 5400 was changed to polyol (A2), which is a polyester polyol with a molecular weight of 1000. Table 2 shows the composition and evaluation results. Compared to Example 2, there were slight tendencies of curing delay and decreased moist-heat resistance durability, which are considered to be caused by the effect of mainly having a polyester structure with only difunctional components. However, even under high temperature and large thickness conditions when devolatilization and curing reaction were performed in an explosion-proof oven at 140°C for 7 minutes, somewhat good curability was exhibited. The coating film of the obtained cured urethane product (I9), although slightly lower in performance than that of Example 2, was remarkably excellent in moist-heat resistance durability. In addition, since it is based on polyester polyol, no particular advantage in flexibility was observed, but it had low tack and was suitable for light release.

[0256] (Example 10) In comparison to Example 2, the polyfunctional polyol (A1-3) was omitted, and the amount of the crosslinking agent polyisocyanate (G1) was increased from 1.15 equivalents to 1.3 equivalents. The only other difference was that acetylacetone was not added. Under the same conditions, a polyol composition (F10) with a nearly 100% non-volatile content, a urethane-forming composition (H10), and a urethane-cured product (I10) on a PET film were prepared.

[0257] Table 2 shows the composition and evaluation results. Even with the composition of Example 10, the curing reaction at high temperature and thickness was excellent when volatile components were removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes. The resulting urethane cured product (I10) coating film exhibited remarkably excellent resistance to moisture and heat. Furthermore, the resulting urethane cured product (I10) coating film, like Example 2, contains a polyalkylene oxide structure mainly composed of bifunctional groups, and because it has few unsaturated monools sealing the ends, it easily forms a flexible and loose network with few defects, and its storage modulus at 25°C is 2.0 × 10⁻⁶. 5 The cured urethane material (I10) was remarkably flexible, with a Pa rating of less than 1.

[0258] [Table 2]

[0259] (Comparative Example 1) A urethane sheet containing a polyol composition (FC1), a urethane-forming composition (HC1), and a cured urethane product (IC1) on a PET film was prepared under the same conditions as in Example 4, except that a hindered phenol compound (D1) was not added.

[0260] Table 3 shows the composition and evaluation results. However, because it does not contain hindered phenol compound (D1), even when using the same amount as in Example 4, which used the highest amount of triazole derivative (C1), the curing performance at high temperatures and thicknesses was inferior when volatile matter was removed and curing reaction was performed in an explosion-proof oven at 140°C for 7 minutes. The resulting urethane cured product (IC1) coating film deteriorated in humid and hot environments, exhibiting odor and resin dissolution. Furthermore, the cohesive force decreased, and the adhesive strength upon re-peeling was less than 0.5 N / 25 mm, resulting in complete cohesive failure. Therefore, it is difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0261] (Comparative Example 2) A urethane sheet containing a polyol composition (FC2), a urethane-forming composition (HC2), and a cured urethane product (IC2) on a PET film was prepared under the same conditions as in Example 5, except that a triazole derivative (C1) was not added.

[0262] Table 3 shows the composition and evaluation results. However, because it does not contain a triazole derivative (C1), even when using the same amount as in Example 5, which used the highest amount of hindered phenol compound (D1), the resulting urethane cured product (IC2) coating film deteriorated in humid and hot environments, exhibiting odor and resin degradation. Furthermore, its cohesive strength decreased, leading to cohesive failure. Its humid and hot durability was insufficient, making it difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0263] (Comparative Example 3) A urethane sheet containing a polyol composition (FC3), a urethane-forming composition (HC3), and a urethane cured product (IC3) on a PET film was prepared under the same conditions as in Example 7, except that a hindered phenol compound (D1) was not added.

[0264] Table 3 shows the composition and evaluation results. However, because it does not contain hindered phenol compounds (D1), when volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes, the curing performance at high temperatures and thicknesses was poor. The resulting urethane cured product (IC3) coating film deteriorated in humid and hot environments, exhibiting odor and resin dissolution. Furthermore, the cohesive force decreased, and the adhesive strength upon re-peeling was less than 0.5 N / 25 mm, resulting in complete cohesive failure. Therefore, it is difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0265] (Comparative Example 4) A urethane sheet containing a polyol composition (FC4), a urethane-forming composition (HC4), and a urethane cured product (IC4) on a PET film was prepared under the same conditions as in Example 7, except that a triazole derivative (C1) was not added.

[0266] Table 3 shows the composition and evaluation results. However, because it does not contain a triazole derivative (C1) and the polyol (A1) used has a larger molecular weight than in Comparative Example 2, the amount of urethane groups is small and the content of hindered phenol compound (D1) is also small. As a result, when volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes, the curing performance at high temperature and thickness was poor. The resulting urethane cured product (IC4) coating film deteriorated in humid and hot environments, exhibiting odor and resin dissolution, as well as reduced cohesive strength and cohesive failure, making it difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0267] (Comparative Examples 5 and 6) Urethane sheets containing polyol compositions (FC5), (FC6), urethane-forming compositions (HC5), (HC6), and urethane cured products (IC5), (IC6) on PET films were prepared under the same conditions as in Example 8, except that a triazole derivative (C1) or a hindered phenol compound (D1) was not added to each.

[0268] Table 3 shows the composition and evaluation results. However, because it does not contain triazole derivatives (C1) or hindered phenol compounds (D1), it exhibited poor curing performance at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes to remove volatile components. The resulting urethane cured products (IC5) and (IC6) showed deterioration in humid and hot environments, exhibiting odor and resin dissolution, as well as reduced cohesive strength and cohesive failure, making them unsuitable for applications requiring resistance to high temperatures and humidity.

[0269] (Comparative Examples 7, 8) Under the same conditions as in Example 9, except that a triazole derivative (C1) or a hindered phenol compound (D1) was not added, urethane sheets containing polyol compositions (FC7), (FC8), urethane-forming compositions (HC7), (HC8), and urethane cured products (IC7), (IC8) on a PET film were prepared.

[0270] Table 3 shows the composition and evaluation results. Although it does not contain a flexible polyalkylene oxide structure and instead contains a polyester structure, the curing performance at high temperatures and thicknesses when curing and volatile components were removed in an explosion-proof oven at 140°C for 7 minutes was only slightly reduced. However, because it does not contain a triazole derivative (C1) or a hindered phenol compound (D1), the resulting urethane cured products (IC7) and (IC8) showed deterioration in humid and hot environments, exhibiting odor and resin dissolution, as well as reduced cohesive strength and cohesive failure, making them unsuitable for applications requiring resistance to high temperatures and humidity.

[0271] [Table 3]

[0272] (Examples 11-13) A urethane sheet containing polyol compositions (F11) to (F13), urethane-forming compositions (H11) to (H13), and urethane cured products (I11) to (I13) on a PET film was prepared under the same conditions as in Example 7, except that the types of hindered phenol compounds (D1) were changed to hindered phenol compounds (D2) and triazole derivatives (C1) to (C2).

[0273] Table 4 shows the composition and evaluation results. Similar to Example 7, in addition to the triazole derivative (C), it contains a hindered phenol compound (D) with a molecular weight of 250 to less than 1000. Similarly, all compositions of Examples 11 to 13 exhibited excellent curability at high temperatures and thicknesses when volatile matter was removed and cured in an explosion-proof oven at 140°C for 7 minutes. The resulting urethane cured coatings (I11) to (I13) showed remarkably excellent resistance to moisture and heat. Furthermore, the resulting urethane cured coatings (I11) to (I13), similar to Example 7, contain a polyalkylene oxide structure mainly composed of bifunctional groups, and because there are few unsaturated monools sealing the ends, they easily form a flexible and loose network with few defects, and the storage modulus at 25°C is 2.0 × 10⁻⁶. 5 The urethane cured products (I11) to (I13) were remarkably flexible, with a Pa level below 1.5.

[0274] (Example 14) A urethane sheet containing a polyol composition (F14), a urethane-forming composition (H14), and a urethane cured product (I14) on a PET film was prepared under the same conditions as in Example 9, except that the types of hindered phenol compounds (D1) were changed to hindered phenol compounds (D2) and triazole derivatives (C1) were changed to triazole derivatives (C2).

[0275] Table 4 shows the composition and evaluation results. Similar to Example 9, there was a slight tendency for delayed curing and decreased resistance to moisture and heat, which is thought to be due to the polyester structure being the main factor, as it consists only of two functionalities. However, even at high temperatures and thicknesses, when volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes, the curing reaction showed somewhat good curing properties. The resulting urethane cured product (I14) coating film showed a slight decrease, similar to Example 9, but remarkably superior resistance to moisture and heat. Furthermore, because it is based on polyester polyol, no special features were observed in terms of flexibility, but it had low tack and was suitable for light peeling.

[0276] (Comparative Examples 9 and 10) In the same conditions as in Example 11, except that the type of triazole derivative (C1) was changed to other compounds (CC1) and (CC2) that do not contain a triazole structure but instead have an imidazole structure or a piperazine structure, a urethane sheet containing a polyol composition (FC9) and (FC10), a urethane-forming composition (HC9) and (HC10), and a urethane cured product (IC9) and (IC10) on a PET film was prepared.

[0277] Table 4 shows the composition and evaluation results. However, because it does not contain a triazole derivative (C), no synergistic effect was observed even when a hindered phenol compound (D1) was used. It is thought that the compound acts as a compatibilizer to improve dispersibility in the urethane resin and appropriately coordinates nitrogen to the metal catalyst, etc., which may have a milder catalytic activity and decomposition reaction during thermal curing at high thickness and high temperature. No effect was observed in suppressing thermal degradation during curing or improving durability under humid heat conditions. When volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes, the curing performance at high temperature and high thickness was poor. The resulting urethane cured products (IC9) and (IC10) showed deterioration in humid heat environments, exhibiting odor and resin degradation. Furthermore, cohesive force decreased and cohesive failure occurred. The humid heat durability was insufficient, making it difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0278] (Comparative Examples 11 and 12) In comparison to Example 12, the hindered phenol compound (D1) with a molecular weight of 250 or more and less than 1000 was changed to a low molecular weight phenol derivative (DC3) that is prone to volatilization and bleeding, and a high melting point phenol derivative (DC4) with a high molecular weight that tends to have low compatibility. Under the same conditions, urethane sheets containing polyol compositions (FC11), (FC12), urethane-forming compositions (HC11), (HC12), and urethane cured products (IC11), (IC12) on a PET film were prepared.

[0279] Table 4 shows the composition and evaluation results. As it does not contain hindered phenol compounds (D) with a molecular weight of 250 or more and less than 1000, the resulting urethane cured products (IC11) and (IC12) showed deterioration after being left standing for 5 days in a humid and hot environment. This deterioration was thought to be due to volatilization, bleeding, phase separation, and a reduction in heat resistance due to the effects of a high melting point, resulting in odor and resin degradation. Furthermore, the cohesive force decreased and cohesive failure occurred, resulting in insufficient humid and heat resistance and making it difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0280] (Comparative Example 13) A urethane sheet containing a polyol composition (FC13), a urethane-forming composition (HC13), and a urethane cured product (IC13) on a PET film was prepared under the same conditions as in Example 14, except that the type of compound was changed from a triazole derivative (C1) to another compound (CC1) that does not contain a triazole structure.

[0281] Table 4 shows the composition and evaluation results. Although it cured well at high thicknesses because it did not contain polyalkylene oxide structures, which are considered to have low heat resistance, and contained many polyester structures, it did not contain triazole derivatives (C). Therefore, even when hindered phenol compounds (D1) were used, no synergistic effect was observed. It is thought that the compound acts as a compatibilizer to improve dispersibility in urethane resin and appropriately coordinates nitrogen to metal catalysts, etc., which may have mildened catalytic activity and decomposition reactions during thermal curing at high thicknesses and high temperatures. However, no improvement in durability under humid heat conditions was observed. The resulting urethane cured product (IC13) coating film deteriorated in humid heat environments, exhibiting odor and resin degradation. Furthermore, its cohesive strength decreased, leading to cohesive failure. Its humid heat durability was insufficient, making it difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0282] [Table 4]

[0283] (Example 15) In contrast to Example 1, in order to exhibit properties such as high solid content, appropriate viscosity, and high-thickness moldability with minimal thickness unevenness at high thicknesses, a urethane prepolymer (E1) consisting of polyol (A1-1) and polyisocyanate (B1) was formed according to the example of preparing a urethane prepolymer (E) and a polyol composition (F) containing a urethane prepolymer. The composition was analyzed by GPC and found to contain 32 area% of unreacted polyol (A1-1), and the molecular weight distribution of the urethane prepolymer (E1) component having urethane groups was remarkably narrow at less than 1.35. Furthermore, the degree of unsaturation calculated from the raw materials used was remarkably low at 0.0018 meq / g.

[0284] Furthermore, 0.03 parts by weight of polyfunctional polyols (A1-3), a triazole derivative (C2), 0.3 parts by weight of a hindered phenol compound (D2), and 0.3 parts by weight of acetylacetone were added, and the mixture was heated to approximately 50°C and mixed to dissolve and disperse, thereby obtaining a polyol composition (F15) containing a urethane prepolymer (E1). The polyol composition (F15) was a homogeneous, transparent liquid at room temperature, exhibited good compatibility, and was expected to produce a urethane cured product with good transparency.

[0285] The polyol composition (F15) has a number average molecular weight of 15,000, which is moderately between 6,000 and 40,000, and a remarkably high non-volatile content of 99.7% by weight, making it promising for low VOCs. Because it contains a urethane prepolymer (E), it has a viscosity of 9.8 Pa·s at 25°C, exhibiting a consistent viscosity with high solid content. It exhibits low flow during curing at high temperatures and thicknesses, and has excellent handling properties when coating and curing with high solid content and thickness, making it promising for high-thickness moldability.

[0286] The obtained polyol composition (F15) and isocyanate compound (G1) are used to determine the amount of hydroxyl groups derived from (F15) (M OH ) and the amount of isocyanate groups derived from (G1) (M NCO ) is the molar ratio of (G1) M NCO / ((F15) M OH The mixture was prepared using a pencil mixer to obtain a ratio of 1.15, and then mixed and degassed using a rotary-orbit mixer to obtain a urethane-forming composition (H15). The urethane-forming composition (H15) was applied to a 38 μm thick PET film using a baker-type applicator to achieve high thicknesses of 120 μm and 500 μm after drying. Subsequently, the mixture was held in an explosion-proof oven set to 140°C for 7 minutes to remove volatile components and allow the curing reaction to proceed, forming a cured urethane product (I15) on the PET film. A release PET sheet was then laminated to form a three-layer sheet structure. After that, the sheet was left to stand for one week in an environment of 23°C and 50% relative humidity to obtain a polyurethane sheet.

[0287] Table 5 shows the composition and evaluation results. The urethane-forming composition (H15) contains a triazole derivative (C2) and a hindered phenol compound (D2). Therefore, at both 120 μm and 500 μm thicknesses, it exhibited excellent curing performance at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes to remove volatile components. It also showed minimal thickness unevenness and excellent high-thickness moldability. Despite the use of a small amount of ketoenol tautomer compound, the viscosity increase rate after 48 hours was less than 20%, demonstrating remarkably good pot life. The resulting urethane cured product (I15) coating film exhibited remarkably excellent moisture and heat resistance.

[0288] Furthermore, the resulting urethane cured product (I1) coating film contains a polyalkylene oxide structure mainly composed of bifunctional groups, and because it has few unsaturated monools sealing the ends, it easily forms a flexible and loose network with few defects, and its storage modulus at 25°C is 1.0 × 10⁻⁶. 5 This urethane cured product (I15) exhibits remarkable flexibility with Pa, and in addition to its resistance to moisture and heat, it is expected to have good conformability to deformation such as bending, movement, and steps. Furthermore, its glass transition temperature is remarkably low at -56°C, demonstrating excellent low-temperature characteristics and good cold resistance, which is expected to provide good impact peel resistance at low temperatures.

[0289] Furthermore, due to the structure in which a urethane prepolymer (E) with relatively linearly extended chains of high molecular weight polyalkylene oxide is crosslinked, the resulting cured urethane product exhibits good adhesive strength of 6 N / 25 mm and good holding power without slippage for more than 1440 minutes at 40°C and a 1 kg load, thus demonstrating practical and excellent adhesive properties.

[0290] (Examples 16-20) Using a urethane prepolymer (E1) containing 32 area of ​​the unreacted polyol (A1-1) obtained in Example 15, polyol compositions (F16) to (F20) were prepared by changing the amount of triazole derivative (C2) and hindered phenol compound (D2) added and the mixing mass ratio to observe synergistic effects. Similarly, urethane-forming compositions (H16) to (H20) and urethane sheets containing urethane cured products (I16) to (I20) on PET films were prepared. The viscosity, appearance, and other properties of each obtained composition were similar to those of Example 15, and high solid differentiation, high thickness moldability, and high transparency could be expected.

[0291] Table 5 shows the composition and evaluation results. In all of the additive amounts and mixing mass ratios in Examples 16-20, both the 120 μm and 500 μm thicknesses exhibited excellent curing performance at high temperatures and thicknesses when volatile matter was removed and curing reactions were carried out in an explosion-proof oven at 140°C for 7 minutes. The coatings also showed minimal thickness unevenness and excellent high-thickness moldability. The resulting urethane cured products (I16)-(I20) coatings exhibited remarkably excellent moisture and heat resistance. Furthermore, the resulting urethane cured products (I16)-(I20) coatings, similar to Example 15, contained a polyalkylene oxide structure mainly composed of bifunctional molecules, and because they contained few unsaturated monools sealing the ends, they easily formed a flexible and loose network with few defects, and the storage modulus at 25°C was 2.0 × 10⁻⁶. 5 The cured urethane products (I16) to (I20) were remarkably flexible, with a Pa of less than 1.

[0292] Furthermore, similar to Example 15, the structure involves crosslinking a urethane prepolymer (E) with relatively linearly extended chains of high molecular weight polyalkylene oxide. As a result, the resulting cured urethane product exhibits good adhesive strength of 0.5 N / 25 mm or more and good holding power, demonstrating practical and excellent adhesive properties.

[0293] (Example 21) For Example 7, a urethane prepolymer (E2) consisting of polyols (A1-2) and polyisocyanate (B1) was formed, and a urethane sheet containing a polyol composition (F21), a urethane-forming composition (H21), and a urethane cured product (I21) on a PET film was prepared under the same conditions.

[0294] The viscosity, appearance, and other properties of each obtained composition were similar to those of Examples 16-20, suggesting promising characteristics such as high solid differentiation, high thickness moldability, and high transparency.

[0295] Table 5 shows the composition and evaluation results. Both the 120 μm and 500 μm thicknesses exhibited excellent curing properties at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes, with minimal thickness unevenness and excellent high-thickness moldability. The resulting urethane cured product (I21) coating film showed remarkably superior moisture and heat resistance. Furthermore, the resulting urethane cured product (I21) coating film contained a polyalkylene oxide structure mainly composed of bifunctional groups, and because it contained few unsaturated monools sealing the ends, it easily formed a flexible and loose network with few defects, and its storage modulus at 25°C was 2.0 × 10⁻⁶. 5 The cured urethane material (I21) was remarkably flexible, with a Pa rating of less than 1.

[0296] Furthermore, because the structure involves crosslinking a urethane prepolymer (E2) with relatively linearly extended chains of high molecular weight polyalkylene oxide, the resulting cured urethane product exhibits good adhesive strength of 0.5 N / 25 mm or more and good holding power, demonstrating practical and excellent adhesive properties.

[0297] (Example 22) For Example 9, a urethane prepolymer (E3) consisting of a polyol (A2) containing a polyester structure and a polyisocyanate (B1) was formed, and a urethane sheet containing a polyol composition (F22), a urethane-forming composition (H22), and a urethane cured product (I22) on a PET film was prepared under the same conditions.

[0298] The properties of each obtained composition, such as viscosity and appearance, were similar to those of Example 21, with high solid content and viscosity despite containing a polyester structure, suggesting potential for low VOC content and high-thickness moldability.

[0299] Table 5 shows the composition and evaluation results. Although there was a slight tendency for delayed curing and decreased resistance to heat and humidity, which is thought to be due to the influence of the polyester structure being the main component of the bifunctional material, both the 120 μm and 500 μm thicknesses exhibited excellent curing performance at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes to remove volatile components. The thickness was also uniform and the moldability at high thicknesses was excellent. The resulting urethane cured product (I22) coating film was slightly inferior to that of Example 21, but showed significantly superior resistance to heat and humidity. Furthermore, because it is based on polyester polyol, it did not exhibit any particular flexibility characteristics, and the adhesive strength was 0.5 N / 25 mm or less, but it had low tack and was suitable for light peeling.

[0300] (Example 23) In contrast to Example 21, a urethane prepolymer (E2) consisting of an aliphatic polyisocyanate (B1) and a polyol (A1-2) mainly composed of a difunctional component was used. Instead, a urethane prepolymer (E4) containing a small amount of a trifunctional component, obtained by combining an alicyclic polyisocyanate (B2), a polyol (A1-2) mainly composed of a difunctional component, and a polyfunctional polyol (A1-3) in a mass ratio of 95:5 was used. Under the same conditions as in Example 21, a polyol composition (F23), a urethane-forming composition (H23), and a urethane sheet containing a cured urethane product (I23) on a PET film were prepared. The properties of each obtained composition, such as viscosity and appearance, showed good handling properties because the trifunctional component was present in small amounts in the prepolymer. Similar to Example 21, high solid differentiation, high thickness moldability, and high transparency could be expected.

[0301] Table 5 shows the composition and evaluation results. Both the 120 μm and 500 μm thicknesses exhibited excellent curing properties at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes, with minimal thickness unevenness and excellent high-thickness moldability. The resulting urethane cured product (I23) coating film showed remarkably superior moisture and heat resistance. Furthermore, the resulting urethane cured product (I23) coating film contained a polyalkylene oxide structure mainly composed of bifunctional groups, and because it contained few unsaturated monools sealing the ends, it easily formed a flexible and loose network with few defects, and its storage modulus at 25°C was 2.0 × 10⁻⁶. 5 The cured urethane material (I23) was remarkably flexible, with a Pa rating of less than 1.

[0302] Furthermore, although it contains small amounts of polyfunctional components, the structure is one in which a urethane prepolymer (E4) is crosslinked with a generally linearly chain-extended high molecular weight polyalkylene oxide. As a result, the resulting cured urethane product has good adhesive strength of 0.5 N / 25 mm or more and good holding power, exhibiting practical and excellent adhesive properties.

[0303] (Example 24) Using the urethane prepolymer (E1) obtained in Example 15, and under similar conditions as in Example 15, except that the polyfunctional polyols (A1-3) were not added, the amount of the crosslinking agent polyisocyanate (G1) was increased from 1.15 equivalents to 1.3 equivalents, and acetylacetone was not added, a polyol composition (F24) with a nearly 100% non-volatile content, a urethane-forming composition (H24), and a urethane sheet containing a cured urethane product (I24) on a PET film were prepared.

[0304] Table 5 shows the composition and evaluation results. Both the 120 μm and 500 μm thicknesses exhibited excellent curing properties at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes, with minimal thickness unevenness and excellent high-thickness moldability. The resulting urethane cured product (I24) coating film showed remarkably superior moisture and heat resistance. Furthermore, the resulting urethane cured product (I24) coating film contained a polyalkylene oxide structure mainly composed of bifunctional groups, and because it contained few unsaturated monools sealing the ends, it easily formed a flexible and loose network with few defects, and its storage modulus at 25°C was 2.0 × 10⁻⁶. 5 The cured urethane material (I24) was remarkably flexible, with a Pa rating of less than 1.

[0305] Furthermore, because the structure involves crosslinking a urethane prepolymer (E1) with relatively linearly extended chains of high molecular weight polyalkylene oxide, the resulting cured urethane product exhibits good adhesive strength of 0.5 N / 25 mm or more and good holding power, demonstrating practical and excellent adhesive properties.

[0306] Furthermore, the compositions containing the urethane prepolymer (E) obtained in Examples 21, 22, and 23 all contain unreacted polyol (A), similar to the composition containing the urethane prepolymer (E1) obtained in Example 15, because they are all formed by chain-extending a bifunctional polyisocyanate (G) to the hydroxyl groups in a bifunctional polyol (F) at an amount of less than 0.5 equivalents.

[0307] [Table 5]

[0308] (Comparative Example 14) Using the composition containing the urethane prepolymer (E1) obtained in Example 15, a urethane sheet containing a polyol composition (FC14), a urethane-forming composition (HC14), and a urethane cured product (IC14) on a PET film was prepared under the same conditions as in Example 18, except that the hindered phenol compound (D2) was not added.

[0309] Table 6 shows the composition and evaluation results. However, because it does not contain hindered phenol compound (D), even when using the same amount as in Example 18, which used the most triazole derivative (C2), the curing performance at high temperatures and thicknesses was inferior when volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes. The resulting urethane cured product (IC14) coating film deteriorated in humid and hot environments, exhibiting odor and resin dissolution. Furthermore, the cohesive force decreased, and the adhesive strength upon re-peeling was less than 0.5 N / 25 mm, resulting in complete cohesive failure. Therefore, it is difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0310] (Comparative Example 15) Using the composition containing the urethane prepolymer (E1) obtained in Example 15, a urethane sheet containing a polyol composition (FC15), a urethane-forming composition (HC15), and a urethane cured product (IC15) on a PET film was prepared under the same conditions as in Example 19, except that the triazole derivative (C2) was not added.

[0311] Table 6 shows the composition and evaluation results. However, because it does not contain the triazole derivative (C), even when using the same amount as in Example 18, which used the highest amount of hindered phenol compound (D2), the resulting urethane cured product (IC15) coating film deteriorated in humid and hot environments, exhibiting odor and resin degradation. Furthermore, its cohesive strength decreased, leading to cohesive failure. Its humid and hot durability was insufficient, making it difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0312] (Comparative Examples 16, 17) Using the urethane prepolymer (E2) obtained in Example 21, urethane sheets containing polyol compositions (FC16), (FC17), urethane-forming compositions (HC16), (HC17), and urethane cured products (IC16), (IC17) on PET films were prepared under the same conditions as in Example 20, except that a triazole derivative (C2) or a hindered phenol compound (D2) was not added, respectively.

[0313] Table 6 shows the composition and evaluation results. However, because it does not contain triazole derivatives (C2) or hindered phenol compounds (D2), it exhibited poor curing performance at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes to remove volatile components. The resulting urethane cured products (IC16) and (IC17) showed deterioration in humid and hot environments, exhibiting odor and resin dissolution, as well as reduced cohesive strength and cohesive failure, making them unsuitable for applications requiring resistance to high temperatures and humidity.

[0314] (Comparative Examples 18, 19) Using the urethane prepolymer (E3) obtained in Example 22, urethane sheets containing polyol compositions (FC18), (FC19), urethane-forming compositions (HC18), (HC19), and urethane cured products (IC18), (IC19) on PET films were prepared under the same conditions as in Example 21, except that triazole derivatives (C2) or hindered phenol compounds (D2) were not added, respectively.

[0315] Table 6 shows the composition and evaluation results. Because it does not contain a flexible polyalkylene oxide structure but instead contains a polyester structure, the curing performance at high temperatures and thicknesses when curing and volatile components were removed in an explosion-proof oven at 140°C for 7 minutes was only slightly reduced. However, because it does not contain a triazole derivative (C2) or a hindered phenol compound (D2), the resulting urethane cured products (IC18) and (IC19) showed deterioration in humid and hot environments, exhibiting odor and resin dissolution, as well as reduced cohesive strength and cohesive failure, making them unsuitable for applications requiring resistance to high temperatures and high humidity.

[0316] [Table 6]

[0317] (Examples 25, 26) Using a composition containing the urethane prepolymer (E2) obtained in Example 21, urethane sheets containing polyol compositions (F25), (F26), urethane-forming compositions (H25), (H26), and urethane cured products (I25), (I26) on a PET film were prepared under the same conditions as in Example 21, except that the types of hindered phenol compounds (D2) were changed to hindered phenol compounds (D1) and triazole derivatives (C2) were changed to triazole derivatives (C1).

[0318] Table 7 shows the composition and evaluation results. Similar to Example 21, in addition to the triazole derivative (C), it contains a hindered phenol compound (D) with a molecular weight of 250 to less than 1000. Similarly, for both compositions in Examples 25 and 26, both at 120 μm and 500 μm thicknesses, the curing reaction at high temperatures and thicknesses was excellent when volatile matter was removed and cured in an explosion-proof oven at 140°C for 7 minutes. The resulting urethane cured coatings (I25) and (I26) exhibited remarkably excellent resistance to moisture and heat. Furthermore, the resulting urethane cured coatings (I25) and (I26), similar to Example 21, contain a polyalkylene oxide structure mainly composed of bifunctional compounds, and because there are few unsaturated monools sealing the ends, they easily form a flexible and loose network with few defects, and the storage modulus at 25°C is 2.0 × 10⁻⁶. 5 The urethane cured products (I25) and (I26) were remarkably flexible, with a Pa of less than 1.

[0319] Furthermore, because the structure involves crosslinking a urethane prepolymer (E2) with relatively linearly extended chains of high molecular weight polyalkylene oxide, the resulting cured urethane product exhibits good adhesive strength of 0.5 N / 25 mm or more and good holding power, demonstrating practical and excellent adhesive properties.

[0320] (Example 27) In comparison to Example 21, the composition was changed from one containing a urethane prepolymer (E2) using only the bifunctional polyol (A1-2) obtained in Example 21 to a composition containing a urethane prepolymer (E5) formed by using a small amount of polyfunctional polyol (A1-3) in combination with polyol (A1-2). The only other changes were the use of acetylacetone and the types of triazole derivative (C) and hindered phenol compound (D). Under similar conditions, a urethane sheet containing a polyol composition (F27), a urethane-forming composition (H27), and a urethane cured product (I27) on a PET film was prepared.

[0321] Table 7 shows the composition and evaluation results. Similar to Example 21, in addition to the triazole derivative (C), it contains a hindered phenol compound (D) with a molecular weight of 250 to less than 1000. Therefore, both the 120 μm and 500 μm thicknesses exhibited excellent curing properties at high temperatures and thicknesses when volatile matter was removed and cured in an explosion-proof oven at 140°C for 7 minutes. The resulting urethane cured product (I27) coating film showed remarkably excellent resistance to moisture and heat. Furthermore, the resulting urethane cured product (I27) coating film, similar to Example 21, contains a polyalkylene oxide structure mainly composed of bifunctional compounds, and because it has few unsaturated monools sealing the ends, it easily forms a flexible and loose network with few defects, and its storage modulus at 25°C is 2.0 × 10⁻⁶. 5 The cured urethane material (I27) was remarkably flexible, with a Pa rating of less than 1.

[0322] Furthermore, although it contains small amounts of polyfunctional components, the structure is one in which a urethane prepolymer (E5) is crosslinked with a generally linearly chain-extended high molecular weight polyalkylene oxide. As a result, the resulting cured urethane product has good adhesive strength of 0.5 N / 25 mm or more and good holding power, exhibiting practical and excellent adhesive properties.

[0323] (Example 28) Using a composition containing the urethane prepolymer (E3) obtained in Example 22, a urethane sheet containing a polyol composition (F28), a urethane-forming composition (H28), and a urethane cured product (I28) on a PET film was prepared under the same conditions as in Example 22, except that the triazole derivative (C) was changed to a triazole derivative (C3) that does not have a well-compatible long-chain alkyl ester structure, and the type of hindered phenol compound (D2) was changed.

[0324] Table 7 shows the composition and evaluation results. In addition to a tendency for delayed curing and decreased resistance to humid heat, which is thought to be due to the influence of the predominantly bifunctional polyester structure, there was a slight tendency for decreased high-thickness moldability, which is thought to be due to the lack of a long-chain alkyl ester structure that is compatible with the triazole derivative (C). However, both the 120 μm and 500 μm thicknesses exhibited excellent curing at high temperatures and thicknesses when cured in an explosion-proof oven at 140°C for 7 minutes, with minimal thickness unevenness and excellent high-thickness moldability. The resulting urethane cured product (I28) coating film showed slightly lower resistance to humid heat than Example 27, but significantly better resistance to humid heat. Furthermore, because it is based on a polyester polyol, it did not exhibit any distinctive flexibility, and the adhesive strength was 0.5 N / 25 mm or less, but it had low tack and was suitable for light peeling.

[0325] (Comparative Examples 20-23) Using the compositions containing the urethane prepolymer (E2) and urethane prepolymer (E3) obtained in Examples 21 and 22, polyol compositions (FC20) to (FC23), urethane-forming compositions (HC20) to (HC23), and urethane sheets containing urethane cured products (IC20) to (IC23) on PET films were prepared under the same conditions, except that the triazole derivative (C2) was changed to a different other compound (CC), and the hindered phenol compound (D2) with a molecular weight of 250 to less than 1000 was changed to a low molecular weight phenol derivative (DC3) that is prone to volatilization and bleeding, or a high molecular weight phenol derivative (DC4) that has a high melting point and tends to have low compatibility.

[0326] Table 7 shows the composition and evaluation results. Comparative Examples 20 and 21, which do not contain the triazole derivative (C), did not exhibit a synergistic effect even when the hindered phenol compound (D1) was used. This is thought to be due to the compound acting as a compatibilizer to improve dispersibility in the urethane resin and the appropriate coordination of nitrogen to the metal catalyst, etc., which moderates the catalytic activity and decomposition reaction during thermal curing at high thickness and high temperature. No effect was observed in suppressing thermal degradation during curing or improving durability under humid heat conditions. When volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes, the curing performance at high temperature and high thickness was poor. The resulting urethane cured products (IC20) and (IC21) showed deterioration in humid heat environments, exhibiting odor and resin degradation. Furthermore, cohesive force decreased and cohesive failure occurred, resulting in insufficient humid heat durability and making them unsuitable for use in applications requiring resistance to high temperature and high humidity environments.

[0327] Furthermore, in Comparative Examples 22 and 23, which did not contain hindered phenol compounds (D) with a molecular weight of 250 or more and less than 1000, even when using a triazole derivative (C1), the resulting urethane cured coatings (IC22) and (IC23) showed deterioration after long-term standing for 5 days in a humid and hot environment. This deterioration was thought to be due to volatilization, bleeding, phase separation, and reduced heat resistance due to high melting point, resulting in odor and resin degradation. Moreover, the cohesive force decreased, leading to cohesive failure. The resulting humid and heat resistance was insufficient, making them unsuitable for use in applications requiring resistance to high temperature and high humidity environments.

[0328] (Comparative Example 24) Using the composition containing the urethane prepolymer (E3) obtained in Example 22, a urethane sheet containing a polyol composition (FC24), a urethane-forming composition (HC24), and a urethane cured product (IC24) on a PET film was prepared under the same conditions as in Example 22, except that the triazole derivative (C2) was changed to a different compound (CC).

[0329] Table 7 shows the composition and evaluation results. Because it does not contain a flexible polyalkylene oxide structure but instead contains a polyester structure, the curing performance at high temperatures and thicknesses was only slightly reduced when volatile matter was removed and curing was performed in an explosion-proof oven at 140°C for 7 minutes. However, because it does not contain a triazole derivative (C2), no synergistic effect was observed even when a hindered phenol compound (D2) was used. It is thought that the compound acts as a compatibilizer to improve dispersibility in the urethane resin and appropriately coordinates nitrogen to the metal catalyst, etc., which may have a milder catalytic activity and decomposition reaction during thermal curing at high thicknesses and high temperatures. No effect was observed in suppressing thermal degradation during curing or improving durability under humid heat conditions. The resulting urethane cured product (IC24) coating film deteriorated in humid heat environments, exhibiting odor and resin dissolution, and furthermore, cohesive force decreased, leading to cohesive failure. This made it difficult to use in applications requiring resistance to high temperature and high humidity environments.

[0330] [Table 7]

[0331] The polyol compositions (F) of the examples of the present invention, all of which contain polyalkylene oxide (A1), have a number average molecular weight of 5,000 to less than 60,000 and are in the range of 0.5 to 20 Pa·s. They tend to maintain a constant viscosity even when highly solidified, and tend to suppress molding defects due to liquid flow. The urethane cured products all have a glass transition temperature of less than -50°C and exhibit excellent cold resistance, which can be expected to prevent peeling under low-temperature impact.

[0332] In these examples, those containing polyalkyle oxide (A1) and acetylacetone all showed a viscosity increase of less than 20% after 48 hours and exhibited excellent pot life. Even in the examples without acetylacetone, the inclusion of a triazole derivative and a hindered phenol compound resulted in a longer pot life, and in all cases, the viscosity increase after 4 hours was less than 20%.

[0333] As shown in the examples above, the polyol composition (F) used in this development is a polyol composition that contributes to the formation of urethane cured products that exhibit remarkably high resistance to moisture and heat, regardless of whether or not a polyol with high moisture and heat resistance is used. By taking advantage of these characteristics, it has been shown that polyurethane can be suitably used in a wide range of applications such as sealants, paints, adhesives, and bonding agents, exhibiting remarkably good curability at high temperatures and high thicknesses, as well as resistance to moisture and heat.

[0334] In particular, the urethane sheet using the urethane cured product (I) of the present invention has been shown to be suitable for use as a urethane adhesive because, in addition to curability and moisture and heat resistance, it has moderate adhesive strength and exhibits re-peelability, flexibility, and cold resistance. Furthermore, because it tends to be highly transparent and exhibits cohesive strength and remarkably high flexibility, it is expected to be suitable for applications such as bending and deformation following ability, printing step following ability, low temperature, high temperature environment, high temperature and high humidity environment, and re-peelability applications, and has been shown to be suitable for use as an adhesive for optical applications such as foldable materials, adhesive for biomedical applications, and adhesive for electronic materials.

Claims

1. A polyol composition (F) comprising a polyol (A), a triazole derivative (C) which is a benzotriazole derivative having one or more phenolic hydroxyl groups represented by the following general formula (1), a hindered phenol compound (D) having a molecular weight of 250 to 1000 and having a long-chain alkyl group with 8 or more carbon atoms and an ester group, and a urethane catalyst containing a metal component, The polyol composition (F) has a triazole derivative (C) content of 0.001% by mass or more and less than 0.1% by mass, and a hindered phenol compound (D) content of 0.1% by mass or more and less than 0.7% by mass. A polyol composition (F) in which the mass ratio of a hindered phenol compound (D) to a triazole derivative (C) (hindered phenol compound (D) / triazole derivative (C)) is in the range of 1.5 to 30 times. 【Chemistry 1】 (In general formula (1), R1, R2, R3, R4, and R5 are selected from alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, cycloalkenyl groups, aryl groups, alkyl-substituted aryl groups, heteroaryl groups, alkyl-substituted heteroaryl groups, alkoxyalkyl groups, acyloxyalkyl groups, hydroxyl groups, halogen atoms, polyoxyalkylene groups, and hydrogen atoms, and one or more of R1, R2, R3, R4, and R5 are substituents having a phenolic hydroxyl group.)

2. The polyol composition (F) according to claim 1, wherein the urethane catalyst containing a metal component is an organometallic compound containing at least one metal selected from the group consisting of Fe, Sn, Zr, Ti, and Al.

3. The polyol composition (F) according to claim 1, having an alkylene oxide residue with 3 carbon atoms, and having a number-average molecular weight of less than 100,000 as calculated by gel permeation chromatography.

4. The polyol composition (F) according to claim 1, wherein the degree of unsaturation is less than 0.020 meq / g.

5. The polyol composition (F) according to claim 1, wherein the non-volatile content concentration is 90% by mass or more.

6. The polyol composition (F) according to claim 1, comprising a urethane prepolymer (E) of a polyol (A) and a polyisocyanate (B).

7. The polyol composition (F) according to claim 6, comprising a urethane prepolymer (E) containing alkylene oxide residues in a range of 50 to 99.5% by mass and polyisocyanate residues in a range of 0.5 to 10% by mass.

8. The polyol composition (F) according to claim 6, wherein the urethane prepolymer (E) contains unsaturated groups in an amount of less than 0.03% by mass.

9. The polyol composition (F) according to claim 6, wherein the urethane prepolymer (E) is a reaction product of a bifunctional polyalkylene oxide (A1) having an unsaturation degree of less than 0.010 meq / g and a molecular weight calculated from its hydroxyl value in the range of 3,000 to 20,000, and a polyisocyanate (B).

10. The polyol composition (F) according to claim 6, wherein the average number of functional groups fave of the total polyols forming the urethane prepolymer (E) is in the range of 1.90 to 2.

20.

11. The polyol composition (F) according to claim 6, wherein the polyisocyanate (B) comprises any aliphatic isocyanate, an alicyclic isocyanate, or a modified thereof, and forms a urethane prepolymer (E), and the average number of functional groups fave of the total polyisocyanates is in the range of 2.00 to 3.

19.

12. A urethane-forming composition (H) comprising the polyol composition (F) and an isocyanate compound (G) as described in claim 1.

13. A urethane cured product (I) comprising a reactant of the urethane-forming composition (H) described in claim 12.

14. A urethane adhesive comprising the urethane cured product (I) described in claim 13.

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