Urethane prepolymer composition

Abstract

To provide a urethane prepolymer composition that contributes to forming polyurethane, with high cohesive power, and markedly good flexibility and cold resistance; a cured urethane product formed by using the urethane prepolymer composition; and a urethane adhesive sheet composed of the polyurethane.SOLUTION: A urethane prepolymer composition (G) includes hydroxyl-terminated urethane prepolymer (E) and polyalkylene oxide (B). The urethane prepolymer (E) is a reaction product of polyol and polyisocyanate (C), including at least one urethane group and at least one hydroxy group in one molecule. The polyalkylene oxide (B) includes polyalkylene oxide (B1) with three or more hydroxy groups. The urethane prepolymer composition (G) has a degree of unsaturation of less than 0.020 meq / g, a number average molecular weight of less than 70,000, and the polyalkylene oxide (B) content of 1-79 wt.%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to urethane prepolymer compositions. [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 a smaller molecular weight compared to acrylic adhesives, and have the advantage of being able to easily adapt to changes in the shape of the adherend.

[0006] On the other hand, polyalkylene oxides containing a large amount of by-product monools with an unsaturated group at one end (hereinafter referred to as unsaturated monools), and urethane prepolymers using them, are used as raw materials for polyurethane. However, polyalkylene oxides containing a large amount of such unsaturated monools, and urethane prepolymers using them, have the problem that the curing (solidification) process that occurs when they react with isocyanate compounds takes a long time, which reduces productivity.

[0007] Patent Document 1 discloses a urethane-forming composition and its prepolymer, which uses a polyalkylene oxide with a narrow molecular weight distribution and significantly low unsaturated monool content, resulting in low viscosity, excellent handling properties, and high curability when manufacturing urethane adhesives. By using these polyalkylene oxides, the curability issues associated with polyalkylene oxides containing a large amount of unsaturated monool are improved, and stain resistance during re-peeling is enhanced. However, there was also a need to ensure a certain viscosity for coating purposes and to achieve high solid differentiation for low VOC reduction.

[0008] Patent Document 2 discloses a hydroxyl-terminated urethane prepolymer solution consisting of a polyol such as a polyalkylene oxide with a relatively low degree of unsaturation and an isocyanate, having a solid content of 80% by mass or more and a constant viscosity of 800 to 8000 mPa·s. However, because cohesive force is imparted by a two-stage polymerization method in which a low molecular weight polyol with a high amount of hydroxyl groups and a molecular weight of 600 or less is added in the second stage after forming an NCO-terminated urethane prepolymer, the resulting urethane cured product tends to have many urethane groups, making the adhesive hard, and the glass transition temperature tends to be high due to the influence of the low molecular weight polyol. As a result, the design does not allow for the expectation of shape changes of the adherend, conformability to steps, or significantly good low-temperature properties derived from the significantly low glass transition temperature of the high molecular weight polyether skeleton, and the adhesive strength of the resulting urethane adhesive is also low. Furthermore, there was a concern that bleeding would occur if a large amount of plasticizer was included and unreacted low molecular weight polyol remained.

[0009] Therefore, there has been a demand for a urethane prepolymer composition that uses a polyalkylene oxide having a certain viscosity, capable of high solid content conversion, and having a small amount of unsaturated monool, and that contributes to the development of cohesive force, significantly good flexibility and cold resistance in the urethane cured product.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] One aspect of the present invention is directed to providing a urethane prepolymer composition that contributes to the formation of a polyurethane having high cohesive force, and significantly good flexibility and cold resistance.

[0012] Another aspect of the present invention is directed to providing a urethane cured product obtained by using the urethane prepolymer composition.

[0013] Still another aspect of the present invention is directed to providing a polyurethane adhesive comprising the polyurethane.

Means for Solving the Problems

[0014] As a result of intensive studies to solve the above problems, the present inventors have surprisingly found that by combining a prepolymer of a specific composition and a specific polyol in a specific ratio, it is possible to achieve high solid content conversion with an appropriate viscosity, and to develop significantly high flexibility and cold resistance, and to contribute to the formation of a urethane cured product capable of developing high cohesive force, thus completing the present invention.

[0015] That is, each aspect of the present invention is as shown in [1] to

[14] below. [1] A urethane prepolymer composition (G) containing a urethane prepolymer (E) with a terminal hydroxyl group and a polyalkylene oxide (B), wherein the urethane prepolymer (E) is a reaction product of a polyol and a polyisocyanate (C), and has at least one urethane group and at least one hydroxyl group in one molecule, the polyalkylene oxide (B) contains a polyalkylene oxide (B1) having three or more hydroxyl groups, the unsaturation of the urethane prepolymer composition (G) is less than 0.020 meq / g, the number average molecular weight calculated by gel permeation chromatography is less than 70,000, and the content of the polyalkylene oxide (B) in the urethane prepolymer composition is in the range of 1 to 79% by weight. The urethane prepolymer composition (G). [2] The urethane prepolymer composition (G) according to [1] above, wherein the molecular weight distribution of the urethane prepolymer (E) calculated by gel permeation chromatography is less than 1.50. [3] The urethane prepolymer composition (G) according to [1] or [2] above, wherein the polyalkylene oxide (B) has a molecular weight calculated from the hydroxyl value of 700 or more and 30,000 or less. [4] The urethane prepolymer composition (G) according to any one of [1] to [3] above, wherein the polyalkylene oxide (B) has an unsaturation of less than 0.070 meq / g. [5] The urethane prepolymer composition (G) according to any one of [1] to [4] above, having a non-volatile content concentration in the range of 80 to 100% by weight and a viscosity at 25 ° C in the range of 0.1 to 30 Pa·s. [6] In the urethane prepolymer (E), the alkylene oxide residue is in the range of 90 to 99.9% by weight, the polyisocyanate residue is in the range of 0.1 to 10% by weight, and the unsaturated group is in the range of 0.03% by weight or less. The urethane prepolymer composition (G) according to any one of [1] to [5] above. [7] A urethane prepolymer composition (G) according to any one of [1] to [6] above, wherein the polyol forming the urethane prepolymer (E) comprises a bifunctional polyalkylene oxide (A) having a degree of unsaturation of less than 0.010 meq / g and a number average molecular weight calculated from the hydroxyl value in the range of 3000 to 10000. [8] A urethane prepolymer composition (G) according to any one of [1] to [7] above, wherein the average number of functional groups fave of the total polyols forming the urethane prepolymer (E) is in the range of 1.85 to 2.20. [9] The urethane prepolymer composition (G) according to [7] above, wherein the polyalkylene oxide (A) forming the urethane prepolymer (E) contains a primary hydroxyl group.

[10] A urethane prepolymer composition (G) according to any one of the above [1] to [9], wherein the polyisocyanate (C) comprises an aliphatic isocyanate, an alicyclic isocyanate, or a modified thereof, forming a urethane prepolymer (E), and the average number of functional groups fave of the total polyisocyanates is in the range of 1.90 to 2.79.

[11] A urethane prepolymer composition (G) according to any one of [1] to

[10] above, comprising 0.01 to 1.0% by weight of a ketoenol tautomer compound (D).

[12] A urethane-forming composition (H) comprising a urethane prepolymer composition (G) described in any of [1] to

[11] above and an isocyanate compound (F).

[13] A urethane cured product (I) containing a reactant of the urethane-forming composition (H) described above

[12] .

[14] A urethane adhesive containing the urethane cured product (I) described in

[13] above. [Effects of the Invention]

[0016] One embodiment of the present invention is a urethane prepolymer composition that can achieve high solid differentiation at a constant viscosity, enabling low VOC content. It exhibits excellent coatability as it is less prone to liquid flow when coated, dried, and cured using a coating machine to obtain polyurethane. It also has good moldability by promoting curing (solidification) through reaction with an isocyanate compound without using a large amount of urethane catalyst, and furthermore, it can produce a highly transparent, adhesive urethane cured product with high cohesive force.

[0017] One embodiment of the present invention is a urethane cured product that exhibits excellent cohesive strength and strength, is expected to improve the stain resistance of the adherend when peeled off again, and shows remarkably good flexibility and low-temperature properties, so it is expected to follow the movement and shape changes of the adherend and is suitable for a wide range of applications such as sealants, paints, adhesives, and bonding agents.

[0018] In particular, a urethane adhesive using a cured urethane product, one embodiment of the present invention, exhibits moderate adhesive strength, re-peelability, and good tackiness, making it suitable for use as a re-peelable adhesive characterized by its wettability to the adherend. Furthermore, it is highly transparent, exhibits cohesive strength, high flexibility, and low-temperature properties, making it suitable for applications in low-temperature environments, such as bending, deformation, movement following, and printing step following. It can be suitably used as an optical adhesive or a biological adhesive. [Modes for carrying out the invention]

[0019] The following describes in detail exemplary embodiments for carrying out the present invention. <Urethane prepolymer composition (G)> A urethane prepolymer composition (G) according to one aspect of the present invention is a urethane prepolymer composition (G) comprising a hydroxyl-terminated urethane prepolymer (E) and a polyalkylene oxide (B), Polyalkylene oxide (B) comprises polyalkylene oxide (B1) having three or more hydroxyl groups, The number average molecular weight of the urethane prepolymer composition (G), calculated by gel permeation chromatography, is less than 70,000, and the degree of unsaturation is less than 0.020 meq / g, and the polyalkylene oxide (B) content in the urethane prepolymer composition is in the range of 1 to 79% by weight.

[0020] When the number-average molecular weight of the urethane prepolymer composition (G), calculated by gel permeation chromatography, is 70,000 or higher, it is easier to increase the cohesive strength of the cured urethane product. However, gelation and the generation of insoluble matter are more likely to occur during urethane prepolymer synthesis, making it necessary to dilute or concentrate with solvents for stable production. Furthermore, viscosity tends to increase and the thixotropy index rises, making it difficult to achieve high solid differentiation with a certain viscosity and handling properties, thus making it difficult to reduce VOCs associated with high solid differentiation.

[0021] Furthermore, if the degree of unsaturation of the urethane prepolymer composition (G) is 0.020 meq / g or higher, the urethane prepolymer (E) and polyalkylene oxide (B) contain a large amount of unsaturated groups. This tends to seal the ends during the formation of the cured urethane product, easily forming low molecular weight material. As a result, curability is poor, cohesive force is reduced, and stain resistance and re-peelability deteriorate, making it difficult to use. Moreover, if the amount of urethane groups or crosslinking components is increased to compensate for this, the cured urethane product becomes hard, making it difficult to exhibit significant flexibility, and low-temperature properties tend to deteriorate. Therefore, it is difficult to adapt it to applications where such properties are required.

[0022] Furthermore, if the weight ratio of polyalkylene oxide (B) in the urethane prepolymer composition (G) is less than 1% by weight, or if polyalkylene oxide (B) does not contain polyalkylene oxide (B1) having three or more hydroxyl groups, the resulting cured urethane will lack sufficient cohesive strength and will have poor re-peelability, making it difficult to use. If the weight ratio exceeds 79% by weight, the resulting cured urethane will not stably exhibit the desired flexibility, and the reaction may proceed unevenly during curing of the urethane, potentially leading to a deterioration in the appearance of the coating film, making it difficult to use.

[0023] The number average molecular weight of the urethane prepolymer composition (G), calculated by gel permeation chromatography, is not particularly limited as long as it is less than 70,000. However, it is preferable that the number average molecular weight be less than 60,000, as this reduces the likelihood of gelation and insoluble matter formation during urethane prepolymer synthesis, allows for a reduction in the amount of solvent and concentration used in manufacturing, and enhances the low-VOC effect. In particular, a number-average molecular weight of 6,000 or more and less than 50,000 is preferred, most preferably 8,000 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 a stable and high cohesive force. The number-average molecular weight of the urethane prepolymer composition (G) calculated by gel permeation chromatography was measured in the same manner as for polyalkylene oxide described later. In this embodiment, the number-average molecular weight of the urethane prepolymer composition (G) was calculated excluding 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.

[0024] Furthermore, the molecular weight distribution of the urethane prepolymer composition (G) is expressed as the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn), and is usually preferably less than 10. More preferably, it is in the range of 1.1 to less than 3.0, and most preferably in the range of 1.3 to less than 2.0, because this tends to lower the thixotropy index, resulting in lower liquid elasticity regardless of viscosity, excellent fluidity, and better moldability. In particular, it is preferable to exhibit a bimodal distribution consisting of a relatively high molecular weight urethane prepolymer component that easily exhibits appropriate viscosity and a relatively low molecular weight polyalkylene oxide component that does not contain urethane groups and contains a trifunctional or higher polyalkylene oxide (B1) that easily exhibits better curability. More preferably, it is preferable to exhibit a bimodal distribution consisting of a residue of polyol components that do not contain urethane groups when forming the urethane prepolymer. By using a relatively high molecular weight urethane prepolymer component and a polyalkylene oxide component containing three or more functional polyalkylene oxides (B1), a bimodal structure is achieved, resulting in a moderate viscosity and a lower thixotropy index, which provides excellent handling properties and high curability, making it preferable to form urethane cured products with better productivity.

[0025] The molecular weight distribution of the urethane prepolymer composition (G) was calculated by excluding 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, in the same manner as the calculation of the number-average molecular weight.

[0026] The content of unsaturated groups in the urethane prepolymer composition (G) is not particularly limited as long as it is less than 0.020 meq / g, but it is preferably 0.015 meq / g or less, more preferably 0.010 meq / g or less, and most preferably in the range of 0.0001 to 0.009 meq / g, as this tends to increase the strength and cohesiveness of the resulting cured urethane. In this embodiment, the content of unsaturated groups was measured by the same method as for polyalkylene oxide (A) described later.

[0027] The polyalkylene oxide (B) content in the urethane prepolymer composition (G) is not particularly limited as long as it is in the range of 1 to 79% by weight, but it is preferably in the range of 5 to 70% by weight because it is easier to achieve both high cohesive strength and high flexibility, and more preferably in the range of 10 to 60% by weight because it is easier to achieve good coating properties with appropriate viscosity regardless of crosslinking conditions, and it is easier to achieve both high cohesive strength and high flexibility, and most preferably in the range of 20 to 55% by weight. This ratio can be calculated from the area ratio of the peak derived from polyalkylene oxide (B) and the relatively high molecular weight peak derived from the urethane prepolymer (E) by gel permeation chromatography analysis of the urethane prepolymer composition (G), and this may be substituted as the weight ratio.

[0028] Furthermore, the urethane prepolymer (G) may contain polyol components that do not contain urethane groups, such as polyol components remaining after the formation of the urethane prepolymer (E). Although these are included in the polyalkylene oxide (B), the proportion of polyalkylene oxide (B1) having three or more hydroxyl groups in the urethane prepolymer composition (G) is preferably in the range of 1 to 50% by weight, and more preferably in the range of 1.5 to 45% by weight, as it is easier to achieve both high cohesiveness and high flexibility. In particular, it is even more preferable that the proportion is in the range of 2 to 35% by weight, and most preferably in the range of 2 to 30% by weight, as it is easier to achieve stable and excellent coating properties regardless of the crosslinking conditions, and is easier to achieve both high cohesiveness and high flexibility. The ratio can sometimes be calculated by determining the proportion in polyalkylene oxide (B) from various structural analyses such as NMR of the preparative components.

[0029] In particular, when the molecular weight of polyalkylene oxide (B) is low, a lower weight ratio of polyalkylene oxide (B) makes it easier to achieve both high cohesiveness and high flexibility, and when the molecular weight of polyalkylene oxide (B) is high, a higher weight ratio of polyalkylene oxide (B) makes it easier to achieve both high cohesiveness and high flexibility. Therefore, it is preferable that the number average molecular weight and weight ratio calculated from the hydroxyl value of polyalkylene oxide (B) satisfy the following general formula. Number average molecular weight of (B) / 2000 < Weight ratio of (B) < Number average molecular weight of (B) / 50 (1 ≤ (B) weight ratio ≤ 79) In particular, it is preferable that the following general formula is satisfied, as this makes it easier to achieve both high cohesive force and high flexibility. Number average molecular weight of (B) / 1000 < Weight ratio of (B) < Number average molecular weight of (B) / 100 (1 ≤ (B) weight ratio ≤ 79) Furthermore, it is preferable that the following general formula is satisfied, as this allows the crosslinking reaction to proceed more uniformly, making it easier to mold with a beautiful coating appearance, and that the material exhibits stable physical properties such as durability regardless of environmental conditions while maintaining flexibility. Number average molecular weight of (B) / 750 < Weight ratio of (B) < Number average molecular weight of (B) / 200 (10 ≤ (B) weight ratio ≤ 60) The relationship between the ratio of polyalkylene oxide (B1) having three or more hydroxyl groups in the urethane prepolymer composition (G) and the number-average molecular weight is also preferably within the above range for the same reasons as the preferred weight ratio of polyalkylene oxide (B), and it is preferable that it satisfies the following general formula. Number average molecular weight of (B1) / 2000 < Weight ratio of (B1) < Number average molecular weight of (B1) / 50 (1 ≤ (B1) weight ratio ≤ 50) In particular, it is preferable that the following general formula is satisfied, as this makes it easier to achieve both high cohesive force and high flexibility. Number average molecular weight of (B1) / 1000 < Weight ratio of (B1) < Number average molecular weight of (B1) / 100 (1 ≤ (B1) weight ratio ≤ 50) Furthermore, it is preferable that the following general formula is satisfied, as this allows the crosslinking reaction to proceed more uniformly, making it easier to mold with a beautiful coating appearance, and that the material exhibits stable physical properties such as durability regardless of environmental conditions while maintaining flexibility. Number average molecular weight of (B1) / 750 < Weight ratio of (B1) < Number average molecular weight of (B1) / 200 (2 ≤ (B1) weight ratio ≤ 35) The content of urethane prepolymer (E) in the urethane prepolymer composition (G) is not particularly limited, but is preferably in the range of 10 to 90% by weight, as it is easier to achieve both high cohesiveness and high flexibility. More preferably, it is in the range of 20 to 85% by weight, as it is easier to achieve both high cohesiveness and high flexibility with a moderate viscosity and excellent coating properties regardless of crosslinking conditions. Most preferably, it is in the range of 40 to 80% by weight. This ratio can be calculated from the area ratio of the peak derived from polyalkylene oxide (B) and the relatively high molecular weight peak derived from urethane prepolymer (E) by gel permeation chromatography analysis of the urethane prepolymer composition (G), and this may be substituted as the weight ratio.

[0030] The urethane prepolymer composition (G) preferably contains 60% by weight or more alkylene oxide residues, more preferably 80-99.9% by weight, and most preferably 95-99.8% by weight, because the resulting cured urethane tends to have significantly good wettability and exhibit a characteristically low glass transition temperature, resulting in excellent low-temperature properties. The content of each residue can be calculated by NMR or the like, but it may also be calculated by analyzing each fraction after separating each component or performing alkaline decomposition as needed. If the raw materials in the composition are known, it may also be calculated from the charging ratio of each raw material and the content of alkylene oxide residues in each raw material. For example, it may be calculated from the number average molecular weight calculated from the hydroxyl value of polyalkylene oxide (A) when forming the urethane prepolymer (E), and polyalkylene oxides (B) and (B1) to be mixed, divided by each initiator residue and unsaturated group, and the charging ratio of each raw material.

[0031] 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 urethane cured product with good mechanical properties. For example, propylene oxide residues and ethylene oxide residues are more preferable alkylene oxide residues, with propylene oxide residues being the most preferred.

[0032] In particular, it is preferable that the urethane prepolymer composition (G) contains 70% by weight or more of propylene oxide residues, more preferably 90 to 99.9% by weight, and most preferably in the range of 95 to 99.8% by weight, as this easily improves the mechanical properties of the cured urethane product. Furthermore, ethylene oxide residues may also be included as they easily improve resistance to humid heat. If included, the content is preferably 0.1% by weight or more, more preferably 0.5 to 15% by weight, and most preferably in the range of 1 to 13% by weight, as this easily maintains cohesive force after humid heat conditions and tackiness after holding humid heat conditions.

[0033] In particular, the resulting urethane cured product is more likely to exhibit significantly better wettability and low-temperature properties, therefore, the urethane prepolymer composition (G) 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 weight or more in the urethane prepolymer composition (G), more preferably 70 to 99.9% by weight, and most preferably in the range of 95 to 99.8% by weight.

[0034] Furthermore, in order for the resulting urethane cured product to exhibit significantly better low-temperature properties and flexibility, the residues derived from low molecular weight polyols with a molecular weight of 600 or less are preferably in the range of 25% by weight or less, more preferably 4% by weight or less, and most preferably intentionally omitted.

[0035] Furthermore, if residues remain during the formation of the urethane cured product, contamination due to bleeding is likely to occur. Therefore, the amount of residues derived from low molecular weight polyols with a molecular weight of 300 or less is preferably in the range of 10% by weight or less, more preferably 1.5% by weight or less, and most preferably intentionally omitted.

[0036] Furthermore, although not particularly limited, aromatic structures such as aromatic amine residues, sugar residues with 6 or more carbon atoms, polyester residues, polyoxytetramethylene residues, and polycarbonate residues are preferably in the range of 20% by weight or less, more preferably 5% by weight or less, and most preferably intentionally omitted, as they tend to exhibit significantly higher ball tack and wettability. The preferred content range for the above structures does not include the above structures in solvents that are removed by volatilization, such as benzene and toluene, or in additives that are non-reactive with isocyanates, such as ester-based plasticizers. Furthermore, although not particularly limited, alicyclic structures are preferably in the range of 20% by weight or less, more preferably 5% by weight or less, and most preferably intentionally omitted, as they tend to exhibit higher flexibility stably.

[0037] While not particularly limited, the urethane prepolymer composition (G) preferably contains polyisocyanate residues in the range of 0.1 to 20% by weight, and more preferably in the range of 0.3 to 10% by weight, because it provides an excellent balance of wettability and cohesiveness in the resulting urethane cured product, and makes it easier to achieve both remarkably high ball tack and re-peelability. In particular, the cohesiveness of the resulting urethane cured product is maintained while the viscosity does not increase easily when mixed with the crosslinking agent even in small amounts of 1.0% by weight or less of the ketoenol tautomer compound, and it is easier to exhibit a characteristically long pot life, so it is even more preferably in the range of 0.5 to 5% by weight, and most preferably in the range of 0.7 to 3% by weight.

[0038] Furthermore, the polyisocyanate residues preferably include bifunctional or more polyisocyanate residues, and examples include aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, aromatic polyisocyanate residues, or modified residues thereof, such as 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, 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. In particular, it is preferable to include aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, or modified residues thereof, as this tends to reduce the coloration of the urethane prepolymer composition (G) and makes it easier to obtain a urethane cured product with better flexibility. More preferably, it is preferable to include aliphatic polyisocyanate residues or modified residues thereof, as this makes it easier to obtain a urethane cured product that is remarkably flexible while maintaining high cohesive strength. Furthermore, while there are no particular limitations on the modified polyisocyanate residues, examples include residues of modified products containing a urethane group, carbodiimide group, allophanate group, urea group, biuret group, isocyanurate group, amide group, imide group, uretonimine group, uretdione group, or oxazolidone group, 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 a modified material, it is preferable to include one or more urethane-modified and allophanate-modified structures, as these tend to exhibit remarkably good wettability.

[0039] The content of each residue in the urethane prepolymer composition (G) 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.

[0040] The viscosity of the urethane prepolymer composition (G) 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 1.5 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 films 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 80% or more and the viscosity is in the range of 0.1 to 30 Pa·s, more preferably in the range of 1.5 to 20 Pa·s with a non-volatile content of 99% or more, and most preferably in the range of 3 to 15 Pa·s with a non-volatile content of 99% 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. It is also preferable that it be a uniform liquid at 0 to 25°C and that it does not separate upon standing.

[0041] Furthermore, although not particularly limited, it is preferable that the fluidity of the liquid is always high, as this makes the actual coating process easier. The thixotropy index (TI value) is preferably 1.5 or less, more preferably 1.3 or less, and most preferably in the range of 1.0 to 1.2. The thixotropy index (TI) was measured at 25°C using a B-type viscometer and spindle No. 21, and calculated according to the following formula. TI=1.2rpm viscosity / 12rpm viscosity When the viscosity and thixotropy index are within this range, the urethane prepolymer composition (G) can be easily mixed uniformly with the isocyanate compound (F) to form the urethane-forming composition (H), degassing is also easier, resulting in excellent handling properties and good coatability when applied using coating machines, thus making it easy to handle.

[0042] The urethane prepolymer composition (G) is preferably transparent to the naked eye, as it has good visibility, making it easy to detect foreign matter, and the resulting cured urethane product tends to be transparent. In particular, the haze value at a width of 100 μm is preferably 5% or less, more preferably 3% or less, and most preferably 1% or less. Alternatively, the haze value of the urethane prepolymer composition (G) may be calculated by coating it onto a PET substrate or the like and dividing by the haze value of the substrate.

[0043] The urethane prepolymer composition (G) may contain other active hydrogen compounds in addition to the urethane prepolymer (E) and polyalkylene oxide (B), and is not particularly limited. For example, to further improve the wettability of the cured urethane, it may contain polyalkylene oxides having two hydroxyl groups or polyalkylene oxides having one hydroxyl group. To impart cohesive force, it may contain polyols different from polyalkylene oxides, such as polyoxytetramethylene glycol, polyester polyols, and polycarbonate polyols, as well as polyols such as amine-initiated polyols, sugar-initiated polyols having 4 or more carbon atoms, amino alcohols, and polyamines. Furthermore, to impart resistance to humid heat, it may contain polyalkylene oxides having one or more hydroxyl groups and ethylene oxide residues. In particular, to further improve wettability while maintaining low-temperature properties and re-peelability, it is preferable to use polyalkylene oxides with two hydroxyl groups and a molecular weight of 3000 or more in combination.

[0044] When other active hydrogen compounds are included in addition to the urethane prepolymer (E) and polyalkylene oxide (B), it is preferable that the amount is in the range of 45% by weight or less, as this makes it easier to maintain and improve better wettability and re-peelability. In particular, excluding the polyol residue that forms the urethane prepolymer (E), the amount is preferably in the range of 25% by weight or less, more preferably 8% by weight or less, and most preferably in the range of 0.01 to 4% by weight.

[0045] On the other hand, if any remains during the formation of the urethane cured product, contamination due to bleeding may easily occur. Therefore, the amount of low molecular weight polyols with a molecular weight of 300 or less is preferably in the range of 10% by weight or less, more preferably 1.5% by weight or less, and most preferably intentionally omitted.

[0046] The urethane prepolymer composition (G) may contain various known additives, such as ketoenol tautomer compounds, acid retarders, other retarders, urethane catalysts, antistatic agents, plasticizers, antioxidants, leveling agents, solvents, chain extenders, fillers, stabilizers, and other additives.

[0047] In particular, although not particularly limited, 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, due to the significant environmental impact. Similarly, although not particularly limited, it is preferable that the solvent does not contain 30% by weight or more, more preferably 10% by weight or more, due to the significant environmental impact. In particular, it is preferable that the solvent does not contain 5% by weight or more, and more preferably 1% by weight 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, do not contain 1% by weight or more, and the urethane prepolymer composition (G) of the present invention is easily obtained with such properties.

[0048] The method for producing the urethane prepolymer composition (G) is not particularly limited, but can be adjusted by, for example, forming a hydroxyl-terminated urethane prepolymer (E) in advance at a temperature ranging from room temperature to 150°C and then mixing it with polyalkylene oxide (B) and additives as needed at any temperature, or by forming a hydroxyl-terminated urethane prepolymer (E) with additives already mixed in at a temperature ranging from room temperature to 150°C and then mixing it with polyalkylene oxide (B) and other additives as needed at any temperature. Furthermore, to adjust the solid content concentration, viscosity, and thixotropy index, dilution, concentration, dehydration, etc., may be performed at any timing, such as before, during, or after the formation of the urethane prepolymer (E). Furthermore, when polyalkylene oxide (B) is added before or during the formation of the hydroxyl-terminated urethane prepolymer (E), the thixotropy index of the urethane prepolymer composition (G) may increase, making coating difficult, or gel-like substances and insoluble matter may be more likely to form. Therefore, it is preferable to add polyalkylene oxide (B) after the formation of the urethane prepolymer (E). However, it is also possible to add it in the middle to late stages of the reaction, or to add a portion beforehand to allow for a coordinated reaction, and the method is not particularly limited.

[0049] The non-volatile content concentration of the urethane prepolymer composition (G) is not particularly limited, but is usually in the range of 10 to 100% by weight, preferably 50 to 100% by weight, in order to obtain good coatability when coating with a coating machine or the like.

[0050] In particular, the urethane prepolymer composition (G) of the present invention has excellent coating properties because the molecular weight of the urethane prepolymer (E) is low, so the viscosity does not become too high even with a high solid content. Furthermore, because it mainly contains polyalkylene oxide (B), a polyfunctional component, as a mixture rather than as an intramolecular component, it easily exhibits a long pot life even with a high solid content, and a significantly long pot life is easily achieved even with the use of a small amount of ketoenol tautomer compound. As a result, it is possible to further differentiate into higher solids and easily exhibit the characteristics of low VOCs, the non-volatile content concentration of the urethane prepolymer composition (G) can be more preferably used in the range of 80 to 100% by weight, even more preferably in the range of 95 to 100% by weight, which makes it easier to take advantage of the characteristics of a longer pot life, and most preferably in the range of 99 to 99.9% by weight.

[0051] Furthermore, although not particularly limited, because it has the characteristic of being remarkably easy to solidify without using a large amount of additives, the urethane prepolymer composition (G) of the present invention preferably contains a component comprising urethane prepolymer (E), polyalkylene oxide (B), and other polyols in a range of 70 to 100% by weight, and more preferably in a range of 80 to 100% by weight. <Urethane prepolymer (E)> The urethane prepolymer (E) is a reaction product of a polyol and a polyisocyanate (C), and refers to a compound having at least one urethane group and at least one hydroxyl group in one molecule, and may also contain amines, thiols, etc., and may contain urea groups, thiourethane groups, etc. In particular, the urethane prepolymer (E) is preferably a reaction product of a component containing at least a polyalkylene oxide (A) and an isocyanate compound (C). If the urethane prepolymer (E) does not contain any hydroxyl groups in a single molecule, its cohesive strength does not increase even when crosslinking agents such as polyisocyanates are used, making it difficult to obtain the desired cured urethane product. Furthermore, if it contains isocyanate groups instead of hydroxyl groups, the reaction proceeds easily due to moisture in the air, making stable production difficult and thus difficult to use. Additionally, if it does not contain any urethane groups in a single molecule, it is difficult to achieve the desired viscosity, resulting in poor moldability, and the cohesive strength of the resulting cured urethane product tends to decrease, making it difficult to use.

[0052] The total sum of the hydroxyl groups (M) of the polyols that form the urethane prepolymer (E) OH The sum of the NCO groups (M) of the polyisocyanate relative to the (M) NCO ) molar ratio (M NCO / M OH The sum of the hydroxyl groups (M) of the polyol is preferably less than 1.0, is easily obtained as hydroxyl group termini, and the urethane prepolymer composition (G) 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 OH The value of ) 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.

[0053] The urethane prepolymer (E) preferably contains alkylene oxide residues, polyisocyanate residues, and unsaturated groups of 0.010 meq / g or less as constituent components.

[0054] The content of unsaturated groups in the urethane prepolymer (E) is not particularly limited, but it is preferable if it is 0.010 meq / g or less, as this tends to increase the strength and cohesive force of the resulting polyurethane. More preferably, it is 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 by the same method as for polyalkylene oxide (A) described later.

[0055] The alkylene oxide residue content in the urethane prepolymer (E) is preferably 70% by weight or more, more preferably 90-99.9% by weight, and most preferably in the range of 95-99.8% by weight, because this tends to result in significantly better wettability of the resulting urethane cured product and a characteristically low glass transition temperature. Furthermore, while the alkylene oxide residue is not particularly limited, for example, alkylene oxide residues having 2 to 20 carbon atoms can be used. However, it is preferable to include alkylene oxide residues having 2 to 3 carbon atoms because this tends to result in a liquid urethane prepolymer composition that is highly transparent and a urethane cured product with good mechanical properties can be easily obtained. For example, propylene oxide residues and ethylene oxide residues are more preferred alkylene oxide residues. In particular, it is preferable that the urethane prepolymer (E) contains 70% by weight or more of propylene oxide residues, more preferably 90 to 99.9% by weight, and most preferably in the range of 95 to 99.8% by weight, as this easily improves the mechanical properties of the cured urethane product. Furthermore, since it easily improves the heat and humidity resistance, ethylene oxide residues may also be included, and if included, the content is preferably 0.1% by weight or more, more preferably 1 to 20% by weight, and most preferably in the range of 5 to 18% by weight.

[0056] 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 60% by weight or more in the urethane prepolymer (E), more preferably 80 to 99.9% by weight, and most preferably in the range of 95 to 99.8% by weight. 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.

[0057] Furthermore, it is preferable to have primary hydroxyl group residues in the urethane prepolymer (E) because it is easier to shorten and suppress the induction period in the initial stages of the reaction during the formation of the urethane prepolymer, and easier to suppress overshoot due to exothermic reaction, thereby stabilizing the quality and improving productivity, which tends to reduce the burden on the environment. In particular, it is preferable to include primary hydroxyl group residues at the end of a polyalkylene oxide with a number average molecular weight of 3000 or more, which has relatively low reactivity, as it is easier to accelerate the initiation reaction and shorten and suppress the induction period. Preferably, the urethane prepolymer (E) contains 0.1% or more primary hydroxyl group residues, and more preferably 0.5% or more primary hydroxyl group residues. There is no particular upper limit to the ratio of primary hydroxyl groups in the hydroxyl group residues, but it is preferably 92% or less, and more preferably 86% or less, because raw materials are easily available, crystallinity tends to be low, and handling is easy. The polyalkylene oxides that contain a small amount or more of primary hydroxyl groups at the termini forming such residues are not particularly limited, but examples include polyalkylene oxides obtained using an iminophosphazenium salt catalyst and a Lewis acid catalyst, and polyalkylene oxides obtained using a boron-based Lewis acid catalyst. Using the above-mentioned polyalkylene oxides makes it easier to obtain the urethane prepolymer (E) and is therefore preferred. The ratio of the primary hydroxyl group residues may be determined by decomposing the urethane prepolymer and analyzing the polyol fraction.

[0058] In order for the resulting urethane cured product to exhibit significantly better low-temperature properties and flexibility, the residues derived from low molecular weight polyols with a molecular weight of 600 or less are preferably in the range of 25% by weight or less, more preferably 4% by weight or less, and most preferably intentionally omitted. In particular, in order for the urethane cured product to exhibit significantly better flexibility, the residues derived from low molecular weight polyols with a molecular weight of 200 or less are preferably in the range of 10% by weight or less, more preferably 1.5% by weight or less, and most preferably intentionally omitted.

[0059] Furthermore, since the resulting urethane cured product tends to exhibit significantly better wettability and low-temperature properties, although not particularly limited, the aromatic structures such as aromatic amine residues, sugar residues with 6 or more carbon atoms, polyester residues, polyoxytetramethylene residues, and polycarbonate residues in the urethane prepolymer (E) are preferably in the range of 20% by weight or less, more preferably 5% by weight or less, and most preferably intentionally omitted. Also, although not particularly limited, the alicyclic structures tend to exhibit higher flexibility more stably, so they are preferably in the range of 20% by weight or less, more preferably 5% by weight or less, and most preferably intentionally omitted.

[0060] 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 to include them in a range where the average number of functional groups of the raw material polyol used for prepolymer formation is less than 2.5, and more preferably in the range of 1.90 to 2.20, most preferably in the range of 1.97 to 2.10, because it is easier to obtain a urethane-forming composition (H) that exhibits a low thixotropy index (TI value), is less likely to produce gel-like substances or insoluble matter, can be differentiated into high solids, and has good coating properties regardless of conditions. Furthermore, the weight content of polyol residues having three or more active hydrogen groups in the urethane prepolymer (E) is preferably in the range of 20% by weight or less, and more preferably in the range of 0 to 10% by weight, for the same reasons as the effect of the preferred average number of functional groups in the raw material polyol used for prepolymer formation. In particular, the weight content of initiator residues of polyols having three or more active hydrogen groups in the urethane prepolymer (E) is preferably in the range of 0 to 3% by weight, most preferably in the range of 0 to 0.3% by weight, and examples of such initiator residues include trimethylolpropane residues, glycerol residues, and pentaerythritol residues. While not particularly limited, the urethane prepolymer (E) preferably contains polyisocyanate residues in the range of 0.01 to 20% by weight, more preferably in the range of 0.1 to 10% by weight, 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 weight is most preferable, as it makes the material more remarkably flexible while maintaining cohesiveness and improves conformability.

[0061] Furthermore, while the polyisocyanate residue is not particularly limited, examples of usable polyisocyanate residues 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 urethane prepolymer composition (G) and makes it easier to obtain a urethane cured product with higher flexibility. More preferably, it is 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.

[0062] 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. 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.

[0063] 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, as this allows the thixotropy index of the urethane prepolymer composition (G) to decrease further, resulting in excellent liquid handling regardless of viscosity, significantly improved fluidity, and thus superior moldability. 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 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. The urethane prepolymer (E) is easily obtained and preferred when using the above-mentioned polyalkylene oxide.

[0064] 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 urethane prepolymer composition (G) using gel permeation chromatography (GPC) and removing peaks such as polyalkylene oxide (B).

[0065] 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 the urethane prepolymer composition may be prepared as is, with some components remaining, or each component may be removed.

[0066] 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 a polyol is added and reacted to form a hydroxyl-terminated urethane prepolymer in two steps, can all be used. 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 single-step polymerization, the significantly good flexibility and significantly low glass transition temperature characteristics tend to be milder, but this can be adapted within a range that does not impair the properties.

[0067] 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. 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. (Urethane prepolymer raw material) The urethane prepolymer (E) is not particularly limited, but it is preferably a reaction product of at least a polyalkylene oxide (A) and a polyisocyanate compound (C).

[0068] The polyalkylene oxide (A) preferred for use in forming the urethane prepolymer (E) 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 in the range of 3000 to 10000 calculated from the hydroxyl value, as this tends to result in good re-peelability, wettability, flexibility, and low-temperature properties.

[0069] The degree of unsaturation of the polyalkylene oxide (A) is preferably 0.010 meq / g or less, as this facilitates faster curing (solidification) of the urethane prepolymer (E) obtained using it in reaction with isocyanate crosslinking agents, etc., and improves 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.

[0070] Here, the "degree of unsaturation (meq / g)" of polyalkylene oxide (A) 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.

[0071] In this embodiment, the degree of unsaturation of polyalkylene oxide (A) 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 (A) which has significantly fewer unsaturated monools, the number of integration cycles in the NMR measurement was set to 500 or more in order to improve the measurement accuracy. The polyalkylene oxide (A) preferred for use in forming the urethane prepolymer (E) is not particularly limited, but is preferred if its number average molecular weight calculated from its hydroxyl value is in the range of 3,000 to 10,000, as this allows the resulting urethane prepolymer composition (G) to easily undergo high solid differentiation at a constant viscosity and improves the wettability, flexibility, and low-temperature properties of the cured urethane. More preferably, it is between 4,000 and 9,000, and most preferably between 4,500 and 7,000.

[0072] The number-average molecular weight of polyalkylene oxide (A) 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 (A).

[0073] The polyalkylene oxide (A) 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 using gel permeation chromatography (GPC) with polystyrene as the standard substance.

[0074] The polyalkylene oxide (A) preferably used in forming the urethane prepolymer (E) preferably contains a bifunctional polyalkylene oxide having two hydroxyl groups. By including a bifunctional polyalkylene oxide (A), the resulting urethane prepolymer (E) becomes linear and has a high molecular weight, exhibiting a low thixotropy index (TI value), and is less likely to produce gel-like substances or insoluble matter, making it easy to obtain a urethane prepolymer composition (G) and a urethane-forming composition (H) with good coating properties under any conditions.

[0075] In particular, the polyalkylene oxide (A) used in the formation of the urethane prepolymer (E) preferably contains primary hydroxyl groups. Even a very small amount of primary hydroxyl groups accelerates the rate of the initial reaction during the formation of the urethane prepolymer, shortening and suppressing the induction period in the initial stages of the reaction, and making it easier to suppress exothermic overshoot, resulting in stable quality, improved productivity, and reduced environmental impact.

[0076] In particular, it is preferable to have a primary hydroxyl group at the terminus of a polyalkylene oxide with a relatively low reactivity and a number-average molecular weight of 3000 or more, as this makes it easier to accelerate the initiation reaction and shorten or suppress the induction period. It is more preferable that the primary hydroxyl group ratio of polyalkylene oxide (A) is 0.1% or more, and even more preferable that it is 0.5% or more.

[0077] The polyalkylene oxide containing a small or more primary hydroxyl groups at the molecular ends is not particularly limited, but examples include polyalkylene oxides obtained using an iminophosphazenium salt catalyst and a Lewis acid catalyst. Using the above-mentioned polyalkylene oxide makes it easier to obtain the urethane prepolymer (E) and is therefore preferred. The upper limit of the proportion of primary hydroxyl groups is not particularly limited, but it is preferably 92% or less, and more preferably 86% or less, because it is easy to produce, readily available, has low crystallinity, and is easy to handle. The proportion of primary hydroxyl groups in the polyalkylene oxide can be measured by known methods such as adding a fluorine compound such as trifluoroacetic anhydride to the hydroxyl groups and measuring NMR, or the polyol component after decomposition of the urethane prepolymer may be analyzed.

[0078] The polyalkylene oxide (A) preferred for use in forming the urethane prepolymer (E) 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 (A) has high industrial value.

[0079] Furthermore, polyalkylene oxide (A) 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 (A) may contain alkylene oxide residues with 3 or more carbon atoms, and may also contain ethylene oxide residues with 2 carbon atoms. The content of ethylene oxide residues in polyalkylene oxide (A) is preferably 50% by weight or less, more preferably 30% by weight or less, and most preferably not included, because it results in low crystallinity, poor solidification at low temperatures, and good moldability.

[0080] The isocyanate compound (C) 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 isocyanate compounds (C) 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).

[0081] Among these, aliphatic isocyanates, alicyclic isocyanates, or modified versions thereof are preferred because they make it easier to obtain a highly transparent and low-coloration urethane prepolymer composition (G). 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. The urethane prepolymer (E) may use different active hydrogen compounds than polyalkylene oxide (A) or different isocyanate compounds than polyisocyanate compound (C) as raw materials, depending on the required properties and viscosity, and is not particularly limited.

[0082] For example, to increase cohesive force, a urethane prepolymer (E) may be formed by reacting polyalkylene oxide (A) and polyisocyanate compound (C) with other polyols such as trifunctional or more polyalkylene oxides or bifunctional polyalkylene oxides with a molecular weight of less than 3000. However, this tends to result in a low thixotropy index (TI value), and further reduces the formation of gel-like substances and insoluble matter, making it easier to obtain a urethane-forming composition (H) with good coating properties regardless of the conditions. Therefore, it is preferable that the total number of functional groups of all polyols used in forming the urethane prepolymer (E) be within a range of less than 2.5, more preferably in the range of 1.85 to 2.20, and most preferably in the range of 1.95 to 2.10. Note that the average number of functional groups of the raw material polyols in this embodiment does not take into account the reduction in the actual number of functional groups due to unsaturated monools produced as by-products during the production of polyalkylene oxide. Furthermore, because the resulting urethane cured product has good flexibility and low-temperature properties that are easily maintained, when used, it is preferable that the amount in the urethane prepolymer (E) be 30% by weight or less, more preferably 10% by weight or less, and most preferably in the range of 0.01 to 4% by weight. For reasons such as increasing cohesive force, polyols with relatively rigid structures, such as polyoxytetramethylene glycol, polyester polyols, aromatic amine-initiated polyols, aliphatic amine polyols, polyols initiated from sugar residues with 6 or more carbon atoms, and polycarbonate polyols, may also be included. However, when used, the amount is preferably in the range of 20% by weight or less, more preferably 5% by weight or less, and most preferably in the range of 0.001 to 1% by weight, as this helps maintain the good flexibility and low-temperature properties of the resulting urethane cured product.

[0083] 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 weight or less, and most preferably in the range of 0.001 to 0.5% by weight.

[0084] Furthermore, for reasons such as improving cohesiveness and moldability, a urethane prepolymer (E) may be formed by reacting polyalkylene oxide (A) and isocyanate compound (C) in combination with other polyisocyanates such as trifunctional or monofunctional isocyanate compounds. However, it is preferable that the average number of functional groups fave of all polyisocyanates used to form the urethane prepolymer (E) be less than 2.8, as this tends to result in a low thixotropy index (TI value), less formation of gel-like substances and insoluble matter, and easier to obtain a urethane-forming composition (H) with good coating properties regardless of the conditions. In particular, it is preferable that the fave be in the range of 1.90 to 2.79, more preferably in the range of 1.98 to 2.49, and most preferably in the range of 2.0 to 2.09, as this reduces the number of components that encapsulate 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. <Polyalkylene oxide (B)> The urethane prepolymer composition (G) of the present invention contains polyalkylene oxide (B) as an essential component. It also contains polyalkylene oxide (B1) having three or more hydroxyl groups in polyalkylene oxide (B) as an essential component.

[0085] If the urethane prepolymer composition does not contain polyalkylene oxide (B), the amount of urethane groups will be low, resulting in insufficient cohesive force and adhesive residue, or the adhesive force will be too high, making the adherend prone to damage, thus making stable re-peelability difficult and the composition difficult to use. Furthermore, if the polyalkylene oxide (B) does not contain polyalkylene oxide (B1) having three or more hydroxyl groups, the cohesive force will be insufficient, resulting in adhesive residue, or the adhesive force will be too high, making the adherend prone to damage, thus making stable re-peelability difficult and the composition difficult to use.

[0086] The polyalkylene oxide (B) is preferable because, even if the molecular weight of the polyalkylene oxide (B) is low, the crosslinked structure of the polyurethane obtained by the reaction between the urethane prepolymer (E) obtained using the polyalkylene oxide (B) and an isocyanate crosslinking agent is less likely to become dense, thus making it easier to achieve better wettability and appropriate tackiness.

[0087] Here, polyalkylene oxide (B1), which has three or more hydroxyl groups in one molecule, can be obtained, for example, by ring-opening polymerization of an alkylene oxide using three or more active hydrogen-containing compounds as initiators in the presence of an alkylene oxide polymerization catalyst. Therefore, polyalkylene oxide (B) will have alkylene oxide residues.

[0088] The degree of unsaturation of the polyalkylene oxide (B) is preferably 0.070 meq / g or less, more preferably 0.050 meq / g or less, and most preferably 0.001 to 0.010 meq / g or less. A degree of unsaturation of 0.070 meq / g or less of polyalkylene oxide (B) is preferable because it tends to accelerate the curing (solidification) of the urethane prepolymer (E) obtained using it in reaction with isocyanate crosslinking agents, etc., and the resulting polyurethane tends to have higher strength and cohesive force.

[0089] Here, the "degree of unsaturation (meq / g)" of polyalkylene oxide (B) 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 a larger amount of unsaturated monools, and a lower degree of unsaturation means a smaller amount of unsaturated monools. In this embodiment, the measurement was performed according to the method of JIS-K1557-6.

[0090] The polyalkylene oxide (B) is not particularly limited as long as it contains polyalkylene oxide (B1) having three or more hydroxyl groups in one molecule. However, in order to exhibit better wettability in addition to good curability, the average number of functional groups of polyalkylene oxide (B1) is preferably in the range of 2.40 to 4.99, and more preferably in the range of 2.55 to 3.99.

[0091] Furthermore, while it is desirable to have fewer unsaturated monools in the urethane prepolymer (E) because a high concentration of unsaturated monools tends to seal the ends during urethane prepolymer formation, resulting in long dangling chains and degrading physical properties, polyalkylene oxide (B) contains polyalkylene oxide (B1) having three or more hydroxyl groups in one molecule. Even when the average number of functional groups decreases due to unsaturated monools, wettability in ball tack and other conditions tends to improve, and better wettability is more easily achieved in addition to good curability. Therefore, it is most preferable that the average number of functional groups of polyalkylene oxide (B1) be in the range of 2.65 to 2.98. Examples of such polyalkylene oxides include those obtained using cesium hydroxide catalysts, iminophosphazenium catalysts, phosphazene catalysts, and complex metal cyanide catalysts (DMC catalysts). Using the above-mentioned polyalkylene oxides is preferable as it makes it easier to obtain the polyalkylene oxide (B) with the above average number of functional groups. However, if the number-average molecular weight is low, such as 1900 or less, general-purpose catalysts such as potassium hydroxide can also be used.

[0092] The polyalkylene oxide (B) is not particularly limited, but it is preferable that it has both moldability and curability when reacting with the urethane prepolymer (E) and isocyanate crosslinking agents, and that the resulting polyurethane tends to have high strength and cohesive force, so that its number average molecular weight calculated from the hydroxyl value is 700 to 30,000, and more preferably 800 to 12,000.

[0093] In particular, it is preferable that the number average molecular weight calculated from the hydroxyl value is 900 to 4500, and more preferably 1000 to 1900, because it has three or more functionalities and a large number of hydroxyl groups, exhibits high reactivity, and is less likely to remain in the resulting urethane cured product.

[0094] On the other hand, although reactivity tends to decrease, the resulting urethane cured product tends to exhibit more pronounced flexibility and wettability. Therefore, in applications where such properties are required, the number average molecular weight calculated from the hydroxyl value is preferably between 4,500 and 12,000, and more preferably between 6,500 and 10,000. Similarly, for the same reason, the number average molecular weight of polyalkylene oxide (B1) in polyalkylene oxide (B) is also preferably within the above range.

[0095] The number-average molecular weight of polyalkylene oxide (B) can be calculated from the hydroxyl value of polyalkylene oxide (B) and the number of hydroxyl groups in one molecule of polyalkylene oxide (B), as calculated by the method described in JIS K-1557-1. Furthermore, this number-average molecular weight was calculated without considering the substantial decrease in the average number of hydroxyl groups due to the unsaturated monool. The polyalkylene oxide (B) preferably has a molecular weight distribution (weight-average molecular weight (Mw) / number-average molecular weight (Mn); Mw / Mn) of 1.1 or less, and more preferably 1.06 or less. A Mw / Mn within this range is preferable because it reduces the amount of low-molecular-weight substances that cause contamination, thus leading to superior stain resistance. Similarly, the polyalkylene oxide (B1) in polyalkylene oxide (B) is also preferably within this molecular weight distribution range for the same reason.

[0096] The molecular weight distribution (Mw / Mn) can be measured using gel permeation chromatography (GPC) with polystyrene as the standard substance.

[0097] The polyalkylene oxide (B) 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 (B) are readily available and the resulting polyalkylene oxide (B) has high industrial value.

[0098] Furthermore, polyalkylene oxide (B) 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 (B) may contain alkylene oxide residues with 3 or more carbon atoms, and may also contain ethylene oxide residues with 2 carbon atoms. The content of ethylene oxide residues in polyalkylene oxide (B) is preferably 50% by weight or less, and more preferably 30% by weight or less, because it is less likely to solidify at low temperatures and has good moldability.

[0099] There are no particular restrictions on the method for producing polyalkylene oxide (B), and it can be produced by conventionally known production methods. For example, it can be produced by ring-opening polymerization of alkylene oxide using a polyvalent initiator with three or more functions and in the presence of a ring-opening polymerization catalyst.

[0100] While there are no particular limitations on the three- or more-functional polyvalent initiators, one or more compounds having three or more active hydrogens can be used, such as triols like glycerin, trimethylolpropane, 1,2,6-hexanetriol, and trifunctional low molecular weight polyols with a molecular weight of 1000 or less, such as Sanyo Chemical Industries' Sannix GP-250, GP-400, GP-600, and GP-1000; tetraols like pentaerythritol and diglycerin; hexol, ammonia, ethanolamine, diethanolamine, and triethanolamine; and amines. In particular, it is preferable to include residues of triols such as glycerin, trimethylolpropane, 1,2,6-hexanetriol, and trifunctional low molecular weight polyols with a molecular weight of 1000 or less. <Additives> The urethane prepolymer composition (G) may contain various known additives, such as ketoenol tautomer compounds, acid retarders, other retarders, urethane catalysts, antistatic agents, plasticizers, antioxidants, leveling agents, solvents, chain extenders, fillers, stabilizers, and other additives.

[0101] In particular, the urethane prepolymer composition (G) of the present invention preferably contains a urethane catalyst containing a metal component and a ketoenol tautomer compound, and more preferably contains both a urethane catalyst containing a metal component and a ketoenol tautomer compound.

[0102] By including a urethane catalyst containing metal components, compared to using only urethane catalysts that do not contain metal components, such as amine catalysts, or catalyst-free systems, the reactivity during prepolymer formation is improved, leading to increased productivity. Furthermore, when forming a urethane cured product using an isocyanate crosslinking agent, the reaction between the urethane prepolymer (E) and polyalkylene oxide (B) and the isocyanate crosslinking agent proceeds preferentially over the reaction between moisture in the air and the isocyanate crosslinking agent, resulting in a significantly improved curability.

[0103] The amount of the urethane catalyst containing a metal component in the urethane prepolymer composition (G) is not particularly limited, but it is preferably in the range of 0.001 to 0.5 parts by weight per 100 parts by weight of the urethane prepolymer (E) because it exhibits appropriate curability and moldability and easily extends the pot life. In particular, the amount of the urethane catalyst containing a metal component is more preferably in the range of 0.001 to 0.1 parts by weight, and most preferably in the range of 0.005 to 0.07 parts by weight, because it easily achieves both curability and a significantly long pot life.

[0104] The urethane catalyst containing a metal component is not particularly limited as long as it is a compound containing a metal component and exhibiting urethane activity. However, it is preferable that it be an organometallic compound containing one or more of the metals Fe, Zr, Ti, and Al, because the catalytic activity can be easily adjusted with various additives to extend the moldable time. In particular, it is preferable that it be one or more of metal chelate catalysts such as Fe chelate catalysts, Zr chelate catalysts, Ti chelate catalysts, and Al chelate catalysts, as they easily extend the pot life, balance curability, and result in good moldability. More preferably, it is an Fe chelate catalyst that easily exhibits a significantly longer pot life.

[0105] While not particularly limited, examples of Fe chelating catalysts include iron trisacetylacetonate, Zr chelating catalysts include zirconium tetraacetylacetonate and zirconium ethylacetoacetate, Ti chelating catalysts include titanium acetylacetonate and titanium ethylacetoacetate, and Al chelating catalysts include aluminum trisacetylacetonate.

[0106] The urethane prepolymer composition (G) preferably contains one or more ketoenol tautomer compounds from among methyl acetoacetate, ethyl acetoacetate, and acetylacetone, as this reduces the catalytic activity of the urethane catalyst containing metal components in liquid and synergistically extends the pot life. Most preferably, it contains acetylacetone, as it can be removed in the drying process and its catalytic activity can be easily reactivated. The content of acetylacetone in the urethane prepolymer composition (G) is preferably in the range of 0.001 to 20 parts by weight, and more preferably in the range of 0.005 to 10 parts by weight.

[0107] In particular, although not limited to the present invention, the urethane prepolymer composition (G) of the present invention has a low molecular weight urethane prepolymer (E) and mainly contains polyalkylene oxide (B) containing polyfunctional components as a mixture rather than intramolecularly. Therefore, it is easier to exhibit a significantly longer pot life even with the use of a small amount of ketoenol tautomer compound, and it is easier to exhibit the characteristics of higher solid differentiation and lower VOCs. For this reason, it is more preferable that the content of the ketoenol tautomer compound in the urethane prepolymer composition (G) is in the range of 0.01 to 1.0% by weight, even more preferably in the range of 0.01 to 0.7% by weight, and most preferably in the range of 0.01 to 0.3% by weight. Furthermore, when the ketoenol tautomer compound is included, the molar ratio (ketoenol tautomer compound / metal catalyst) to the urethane catalyst containing the metal component is preferably in the range of 3 to 1000 times, and even more preferably in the range of 5 to 100 times, in order to further extend the pot life.

[0108] In particular, it is preferable that the content of the ketoenol tautomer compound in the urethane prepolymer composition (G) is in the range of 0.01 to 1.0% by weight, and that the time required for a 20% increase in viscosity when the isocyanate crosslinking agent C2770 is mixed so that the amount of NCO groups is 1.3 equivalents relative to the total amount of hydroxyl groups in the urethane prepolymer composition (G) is 10 hours or more, and that such properties are easily obtained. More preferably, the content of the ketoenol tautomer compound is in the range of 0.01 to 0.7% by weight, and the time required for a 20% increase in viscosity when the isocyanate crosslinking agent C2770 is mixed with the urethane prepolymer composition (G) in an amount of 1.3 equivalents of NCO groups relative to the total amount of hydroxyl groups is 24 hours or more. Most preferably, the content of the ketoenol tautomer compound is in the range of 0.01 to 0.3% by weight, and the time required for a 20% increase in viscosity when the isocyanate crosslinking agent C2770 is mixed with the urethane prepolymer composition (G) in an amount of 1.3 equivalents of NCO groups relative to the total amount of hydroxyl groups is 48 hours or more, and such properties are easily obtained.

[0109] 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 between reactivity and physical properties.

[0110] Antistatic agents are not particularly limited, but examples include alkali metal salts and ionic liquids. For example, lithium salts such as lithium bis(trifluoromethanesulfonylimide), quaternary ammonium salts, imidazolium salts, phosphonium salts, and pyridinium salts are examples.

[0111] 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.

[0112] Examples of organic solvents include methyl ethyl ketone, ethyl acetate, butyl acetate, toluene, xylene, acetone, benzene, dioxane, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, glycol ether solvents such as triethylene glycol dimethyl ether and diethylene glycol diethyl ether, or mixtures thereof. From the viewpoint of solubility and boiling point of the organic solvent, ethyl acetate, toluene, methyl ethyl ketone, glycol ether solvents, or mixtures thereof are particularly preferred. These solvents can be added at any stage. <Urethane-forming composition (H)> The urethane-forming composition (H) is a composition comprising the above-mentioned urethane prepolymer composition (G) and an isocyanate compound (F).

[0113] The isocyanate compound (F) is not particularly limited, but it can be the same as the isocyanate compound (C), and the preferred isocyanate is also the same. The isocyanate compound (F) and the isocyanate compound (C) may be the same or different.

[0114] In particular, it is preferable to include an allophanate structure in the isocyanate compound (F) because it improves compatibility, resulting in a more transparent urethane-forming composition (H), which is significantly more flexible, has excellent wettability, and makes it easier to obtain a highly transparent cured urethane.

[0115] The allophanate structure is not particularly limited, but for example, the structure shown in the following chemical formula (1) is preferably included.

[0116] [ka]

[0117] [In the above chemical formula (1), R1 is a monool residue or a polyol residue.] Furthermore, when R1 in the above chemical formula (1) is a polyol residue, there are no particular limitations, but for example, the structure shown in the following chemical formula (2) is preferably included.

[0118] [ka]

[0119] [In the above chemical formula (2), 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.] In chemical formula (2), R1 is preferably a monool residue or polyol residue having 1 to 50 carbon atoms, as this exhibits superior compatibility.

[0120] In chemical formula (2), 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.

[0121] Furthermore, the isocyanate compound (F) 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 superior 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.

[0122] Among them, it preferably contains an allophanate-modified product of 1,6-hexamethylene diisocyanate because it has high reactivity, good productivity of the urethane cured product, and the resulting urethane cured product is more remarkably flexible and tends to have excellent wettability.

[0123] The average number of isocyanate functional groups calculated by the gel permeation chromatography (GPC) method of the polyisocyanate (F) is preferably in the range of 1.90 to 2.99, more preferably in the range of 1.95 to 2.79, still more preferably in the range of 1.98 to 2.49, and most preferably in the range of 2.00 to 2.19 because it can exhibit more flexibility and wettability while maintaining cohesion. As a method for calculating the average number of isocyanate functional groups of the polyisocyanate (F), it is calculated by the following formula using the number average molecular weight and isocyanate content (isocyanate group concentration) of the polyisocyanate calculated by gel permeation chromatography (GPC). Number of isocyanate functional groups = (Polyisocyanate number average molecular weight × Isocyanate group concentration) / (42 × 100) When using a plurality of polyisocyanates, the average number of isocyanate functional groups of the entire polyisocyanate (F) may be determined from the usage amount of each raw material, the average number of isocyanate functional groups of each raw material, and the polyisocyanate number average molecular weight. The content of the isocyanate compound (F) in the urethane-forming composition (H) is not particularly limited, but the amount (M NCO ) of isocyanate groups derived from the isocyanate compound (F) relative to all the hydroxyl groups in the urethane prepolymer composition (G) NCO / M OH ) is preferably 0.5 or more and less than 4.0 in molar ratio, more preferably in the range of 0.9 or more and less than 2.5 because the curability is better and it is less likely to generate carbon dioxide gas foaming marks due to the reaction of excess NCO groups in the resulting urethane cured product with moisture in the air, etc., and most preferably in the range of 1.0 or more and less than 1.7.

[0124] Furthermore, the weight ratio (weight of (G) / weight of (F)) of the urethane prepolymer composition (G) to the isocyanate compound (F) in the urethane-forming composition (H) is not particularly limited, but is usually in the range of 99 / 1 to 20 / 80, and preferably in the range of 98 / 2 to 50 / 50. In particular, the urethane prepolymer composition (G) of the present invention readily forms a urethane cured product that exhibits good cohesive strength and re-peelability without mixing in a large amount of low molecular weight polyol with a high hydroxyl value. Therefore, curing with a small amount of isocyanate compound (F) is more preferable, and the weight ratio of the urethane prepolymer composition (G) to the isocyanate compound (F) (weight of (G) / weight of (F)) is preferably in the range of 97 / 3 to 85 / 15, and most preferably in the range of 96 / 4 to 90 / 10. By including it in the above ratio, a urethane cured product that is more remarkably flexible while maintaining cohesive strength is easily obtained. Furthermore, because curing is possible with a small amount of isocyanate compound (F) without mixing in a large amount of low molecular weight polyol with a high hydroxyl value, the thickening after mixing with the crosslinking agent is gradual, the pot life is extended, and handling properties are more easily improved.

[0125] The urethane-forming composition (H) may contain, and may also contain, additives as exemplified in the urethane prepolymer composition (G), and additional additives may be added as needed. The range of preferred types and contents of additives is the same as the range of preferred types and contents of additives in the urethane prepolymer composition (G). When the types and contents of additives are within this range, good coatability can be obtained when coating the urethane-forming composition (H) with a coating machine, and it can be made easy to handle by exhibiting good pot life and curing properties, and the resulting cured urethane product is more likely to exhibit remarkable flexibility.

[0126] 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.

[0127] 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.

[0128] 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 urethane prepolymer composition (G) are those exemplified. The preferred concentration range and solution viscosity are also equivalent to those of the urethane prepolymer composition (G). 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.

[0129] The urethane-forming composition (H) has a low molecular weight of less than 100,000 for the urethane prepolymer (E), and mainly contains polyalkylene oxide (B), a polyfunctional component, as a mixture rather than as an intramolecular component. Therefore, it exhibits gradual thickening after mixing with the isocyanate compound (F), a long pot life, excellent handling properties, a non-volatile content of 80% by weight or more, and preferably takes 4 hours or more to increase viscosity by 20%, and is easily obtained with such properties.

[0130] In particular, it is preferable that the urethane-forming composition (H) has a non-volatile content of 80% by weight or more and a ketoenol tautomer compound content in the range of 0.01 to 1.0% by weight, and that the time required for a 20% increase in viscosity is 15 hours or more, and that such properties are easily obtained. More preferably, the non-volatile content is 90% by weight or more, the ketoenol tautomer compound content is in the range of 0.01 to 0.7% by weight, and the time required for a 20% viscosity increase is 24 hours or more. Most preferably, the non-volatile content is 95% by weight or more, the ketoenol tautomer compound content is in the range of 0.01 to 0.3% by weight, and the time required for a 20% viscosity increase is 48 hours or more. Such properties are easily obtained.

[0131] <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 urethane prepolymer (E) or polyalkylene oxide (B) in the urethane-forming composition (H) and an isocyanate compound (F).

[0132] 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.

[0133] Furthermore, in order to achieve good curability, 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.

[0134] 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.

[0135] <urethane sheet> The urethane-forming composition (H) exhibits remarkably excellent coatability when applied using a coating machine, etc., allowing for the production of urethane-cured sheets (I) with uniform thickness ranging from thin films to thicker films.

[0136] In the case of urethane sheets, there are no particular limitations 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 1000 μm, because the appearance of the coating film is particularly good. In particular, a thickness of 45 to 300 μm is preferred because it is easy to obtain a urethane-forming composition (H) with a high solid content and appropriate viscosity, making it easy to obtain a urethane cured product (I) sheet with a uniform thickness up to a high thickness.

[0137] 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.

[0138] <Urethane adhesive> Because the cured urethane product (I) exhibits excellent re-peelability, remarkably good flexibility, and low-temperature properties, it can be particularly suitably used as a urethane adhesive when included in the product. Furthermore, it is easy to form from a high-solids-content raw material, and tends to result in a low-VOC product with a small environmental impact, which is preferable.

[0139] The urethane adhesive of the present invention uses a polyalkylene oxide with a low degree of unsaturation, which makes it easy to maintain crosslinking points even when the molecular weight is increased, and it easily exhibits good flexibility and adhesive properties, as well as impact resistance from low to high temperatures. Furthermore, since the adhesive-forming composition has an appropriate viscosity and is easily obtained with a uniform composition, it tends to have excellent transparency.

[0140] The urethane adhesive of the present invention has an elastic modulus of 2 × 10 at a frequency of 1 Hz and 25°C. 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~1.5×10 5 The range is Pa. 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 the adhesive to conform to uneven surfaces of the adherend while exhibiting adhesive properties such as holding power and tackiness, thus suppressing the generation of air bubbles.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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 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, the peeling mode is preferably interfacial peeling.

[0145] 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 25 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 test specimens in accordance with JIS Z0237. Using an Orientec RTG-1210 tensile testing machine, the adhesive strength was measured at 180° peel (N / 25 mm) in accordance with JIS Z0237 under conditions of 23°C, 50% RH atmosphere, peel angle of 180°, and tensile speed of 300 mm / min.

[0146] The ball tack of urethane adhesive, measured according to the JIS Z0237 method, is not particularly limited, but is preferably 6 or higher. In particular, a range of 21 or higher is preferred because it adheres instantly and easily follows uneven surfaces, more preferably 25 or higher, and most preferably 32 or higher. A ball tack of 21 or higher exhibits significantly superior wettability, which can be expected to shorten bonding time and further improve productivity by suppressing misalignment.

[0147] The ball tack of the urethane adhesive of the present invention is a value evaluated in accordance with JIS Z0237, and specifically, it is the ball number of a steel ball that stopped within a 10 cm distance of the adhesive under the conditions of an inclination angle of 30 degrees and a run-up distance of 10 cm.

[0148] The holding power of the urethane adhesive used in the present invention, as measured by the JIS Z0237 method, is not particularly limited, but is preferably 100 minutes or more at 40°C, more preferably 24 hours or more, and most preferably 24 hours or more with a displacement of less than 1 mm and virtually no creep.

[0149] The holding power of the urethane adhesive was evaluated according to JIS Z0237. Specifically, a 25mm x 25mm adhesive surface was bonded to a SUS substrate, and the time it took for a weight to fall was evaluated under conditions of 40°C and a static load of 1kg. If the holding power is 100 minutes or more under 40°C conditions, it indicates that there are few migrating components, and re-peelability can be expected due to high cohesive force.

[0150] 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 80 μm, more preferably less than 0.4%, and most preferably less than 0.2%. A haze of less than 1% at a thickness of 80 μm is preferable because it provides high transparency, excellent visibility, and a good appearance. While 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 an adhesive with a haze of less than 1% at a thickness of 80 μm is 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.

[0151] 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%.

[0152] 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%. Urethane adhesives are flexible at room temperature and retain their elasticity even at high temperatures. They offer excellent vibration absorption, adhesion, low-temperature properties, and tackiness, and are expected to conform to printing surface irregularities, provide impact resistance, and maintain adhesion from low to high temperatures.

[0153] Urethane adhesives can be provided in any shape, such as film, sheet, plate, or block.

[0154] <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.

[0155] 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.

[0156] 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.

[0157] 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 10 μm to 1000 μm, more preferably in the range of 15 μm to 500 μm, and most preferably in the range of 45 μm to 300 μm. In particular, for optical adhesive sheets for film sensors, a range of 15 μm to 150 μm is preferred, and for optical adhesive sheets for glass sensors between touch panels and cover panels, a range of 50 μm to 300 μm is preferred.

[0158] 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.

[0159] 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 urethane prepolymer composition (G) 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.

[0160] 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 preferably in the range of 50 to 200°C, more preferably 70 to 180°C, and even more preferably 80 to 150°C. When a thermoplastic resin is used as the base material, 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 deterioration of the base material or change in color.

[0161] 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, and other home appliances; optical adhesive sheets used for adhesion of liquid crystal displays and touch panels; surface protection tapes in manufacturing processes; waterproof tapes; conductive tapes; and heat dissipation tapes. These can be suitably used in these applications.

[0162] The urethane adhesive and adhesive sheet of the present invention can be suitably used in applications requiring flexibility, such as adhesion and shatter prevention of fragile substrates like glass, adhesion of equipment susceptible to vibration and shock, applications requiring conformability to bending of foldable materials and conformability to printed steps in touch panels, and applications requiring conformability to moving biological materials. Specifically, it can be used in optical applications such as touch panels, electrical and electronic component applications, and biomedical tapes. 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 aforementioned electronic devices.

[0163] Specific optical applications of optical adhesive sheets are not limited, but examples include adhesive sheets used for touch panels and displays in mobile phones, smartphones, tablets, foldable terminals, car navigation systems, personal computers, ticket vending machines, etc., and for bonding surrounding functional films such as ITO film, silver mesh, copper mesh, and polarizing plates. The operating method of the touch panel is not particularly limited, and it can be suitably used with resistive, capacitive, optical, ultrasonic, and electromagnetic induction types. [Examples]

[0164] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. The raw materials and evaluation methods used in the following examples and comparative examples are as shown below. (Raw material 1) Polyalkylene oxide (A1 or AC1) used in the examples and comparative examples The properties of the polyalkylene oxides used in the examples and comparative examples were determined by the following method. <Hydroxyl value and number-average molecular weight of polyalkylene oxides> The hydroxyl value of the polyalkylene oxide was measured in accordance with the method described in JIS-K1557-1. Further, the number average molecular weight of the polyalkylene oxide was calculated from the hydroxyl value of the polyalkylene oxide and the number of hydroxyl groups in one molecule of the polyalkylene oxide. <GPC number average molecular weight, weight average molecular weight, molecular weight distribution> GPC measurement was performed on the polyalkylene oxide, or urethane prepolymer, or urethane-forming composition 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.

[0165] An amount of 10 mg of solid content and 10 ml of THF were added to a sample bottle, dissolved by standing overnight, and the sample was obtained by filtering with a PTFE cartridge filter (0.5 μm). As a detector, an RI detector RI8020 was used, and as measurement columns, two TSKgel GMR-HHR columns in series were used (both manufactured by Tosoh Corporation). The measurement conditions were as follows: measurement was performed at a column temperature of 40 °C, a flow rate of 1.0 ml / min, and a solvent of THF. Analysis of the number average molecular weight and weight average molecular weight was performed using a third-order approximation curve calibration curve with standard polystyrene manufactured by Tosoh Corporation. Further, the ratio Mw / Mn was used as the molecular weight distribution. For the measuring device, HLC-8320GPC manufactured by Tosoh was used, and for the analysis, HLC-8320GPC-ECOSEC-WorkStation manufactured by Tosoh was used. <Degree of unsaturation and average functionality of polyalkylene oxide> The degree of unsaturation of the polyalkylene oxide was measured in accordance with the NMR method described in Polymer Journal 1993, 50, 2, 121-126 with 800 scans. Further, the degree of unsaturation was converted to the amount of monool having an unsaturated group at one end, and the average functionality of the actual hydroxyl groups was calculated. In addition, since the raw materials are known, the degree of unsaturation in the urethane prepolymer and urethane-forming composition was calculated from the degree of unsaturation and the amount ratio of each polyalkylene oxide used. <Ethylene oxide content (wt%)> Nuclear magnetic resonance (NMR) spectroscopy was used to measure 1H NMR using tetramethylsilane-containing deuterated chloroform 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). <Ratio of primary hydroxyl groups> Nuclear magnetic resonance (NMR) spectroscopy was used to measure the 1H NMR of samples treated with trifluoroacetic anhydride using tetramethylsilane-containing deuterated chloroform as the deuterated solvent. The primary hydroxyl group ratio of the polyol was calculated from the integral values ​​at approximately 4.3 ppm (methylene with esters derived from primary OH groups) and approximately 5.2 ppm (methine with esters derived from secondary OH groups) of the samples treated with trifluoroacetic anhydride. (Raw material 1-1) Polyalkylene oxide (A1) used in the example, polyalkylene oxide (AC1) used in the comparative example. Polyalkylene oxides (A1), (A3), (AC2): These were polyoxypropylene glycols obtained by adding a sufficiently dehydrated propylene oxide to a bifunctional polyoxypropylene glycol with a molecular weight of 400, using an imino group-containing phosphazenium salt (IPZ) catalyst and triisopropoxyaluminum to thoroughly dehydrate and desolvate the mixture. The resulting polyalkylene oxides contained a small amount of primary hydroxyl groups. Polyalkylene oxide (A2): This polyoxyethylene-propylene glycol was obtained by thoroughly dehydrating and desolvating a difunctional polyoxypropylene glycol with a molecular weight of 400 by using an imino group-containing phosphatazenium salt (IPZ) catalyst in combination with triisopropoxyaluminum, and adding thoroughly dehydrated propylene oxide and ethylene oxide. It was a polyalkylene oxide with a high primary hydroxyl group ratio. Polyalkylene oxides (AC1), (AC3): Polyalkylene oxides produced by adding propylene oxide using a potassium hydroxide catalyst by a conventional method. Table 1 shows the properties of polyalkylene oxides (A1), (A2), (A3), and (AC2). All of them had extremely low unsaturated monool content (very low degree of unsaturation), a narrow molecular weight distribution, and possessed a small or more primary hydroxyl groups, making them polyalkylene oxides that could be expected to shorten or suppress the induction period. Furthermore, (AC2) had a high molecular weight, making it a relatively viscous polyalkylene oxide, and therefore, a urethane prepolymer composition obtained mainly using it could not be expected to have a certain viscosity, low thixotropy, and high solid differentiation.

[0166] Table 1 shows the properties of polyalkylene oxide (AC1). It has a high amount of unsaturated monool (high degree of unsaturation) and a broad molecular weight distribution. Therefore, urethane prepolymer compositions obtained mainly using it are polyalkylene oxides that cannot be expected to achieve a degree of unsaturation of less than 0.020 meq / g and a molecular weight distribution of less than 1.50.

[0167] [Table 1]

[0168] (Raw material 1-2) Polyalkylene oxide (B1) having three or more hydroxyl groups used in the example. Polyalkylene oxide (B1-1): A commercially available trifunctional polyalkylene oxide, which is a polyoxyethylene propylene oxide with a relatively low degree of unsaturation and a small amount of monool.

[0169] Polyalkylene oxides (B1-2), (B1-3): These are commercially available trifunctional polyalkylene oxides with a relatively low molecular weight, resulting in a slightly lower degree of unsaturation. Polyalkylene oxide (B1-4): This polyoxypropylene glycol is obtained by adding a well-dehydrated propylene oxide to a trifunctional, glycerin-initiated polyoxypropylene glycol with a molecular weight of 400, using an imino group-containing phosphatazenium salt (IPZ) catalyst and triisopropoxyaluminum to thoroughly dehydrate and desolvate the material. It has a remarkably low amount of unsaturated monools and is a polypropylene oxide with a high average number of functional groups, approximately 3.

[0170] Polyalkylene oxide (BC1-1): This is a commercially available polyalkylene oxide with a high molecular weight, resulting in a high degree of unsaturation. It contains polyalkylene oxides with three hydroxyl groups, but the actual average number of functional groups is close to 2, making it a polypropylene oxide.

[0171] [Table 2]

[0172] The polyalkylene oxides (A), (AC), (B1), and (BC-1) used in the examples and comparative examples were all used after heating and vacuum dehydration. Furthermore, polyalkylene oxides prepared using or in combination with the IPZ catalyst were used after the catalyst was removed. (Raw material 2) Isocyanate compounds (C), (I) used in the examples and comparative examples Isocyanate (C1):1,6-Hexamethylene diisocyanate (HDI) Isocyanate (C2): Isophorone diisocyanate (IPDI) Isocyanate (I): Allophanate-modified bifunctional HDI-based crosslinking agent (Tosoh Corporation's Coronate 2770) (Raw material 3) Ketoenol tautomer compound (D) used in the examples and comparative examples Ketoenol tautomer compound (D1): Acetylacetone (Ingredient 4) Additive Urethane catalyst: Iron trisacetylacetonate (Fe(acac)3) (Preparation of urethane prepolymer (E) and urethane prepolymer composition (G)) A four-necked round-bottom flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer was used to add a polyol such as polyalkylene oxide (A) and a 10% MEK masterbatch of iron trisacetylacetonate (Fe(acac)3) as a urethane catalyst, in the amount specified in the table based on solid content. Vacuum dehydration and solvent removal were then performed at 100°C for 2 hours.

[0173] After cooling, a predetermined amount of isocyanate compound (C) was added, and the reaction was carried out by raising the temperature to 70°C in a substantially solvent-free and plasticizer-free manner. 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 urethane prepolymer (E). After cooling, polyalkylene oxide (B1) was added, and if necessary, ketoenol tautomer compound (D) was added, and the mixture was prepared to obtain urethane prepolymer composition (G).

[0174] The molecular weight distribution of the urethane prepolymer (E) was measured using the GPC method with tetrahydrofuran as the solvent and polystyrene as the standard substance before the addition of polyalkylene oxide (B1), and calculated from the peak after excluding the residual polyalkylene oxide. The content of residual polyalkylene oxide (A) and urethane prepolymer (E) was calculated from the area ratio of the polyalkylene oxide component to the prepolymer component obtained from the above measurement. The number-average molecular weight of the urethane prepolymer composition (G) was calculated by GPC using tetrahydrofuran as the solvent and polystyrene as the standard substance, after the addition of polyalkylene oxide (B1) and before the addition of the ketoenol tautomer compound (D1).

[0175] The thixotropy index (TI value) of the urethane prepolymer composition (G) was measured using a B-type viscometer after adding polyalkylene oxide (B1) and ketoenol tautomer compound (D1).

[0176] The content of each component in the urethane prepolymer composition (G) was calculated from the content of the urethane prepolymer (E), the remaining polyalkylene oxide component, and the weight of the added polyalkylene oxide-ketoenol tautomer compound (D1). Note that the urethane catalyst and absorbed moisture, which may be used during urethane prepolymer formation, were not considered in the calculation of the composition ratio. (Preparation of urethane-forming composition (H) and urethane cured product (I)) In the examples and comparative examples, predetermined amounts of each raw material (urethane prepolymer composition (G), isocyanate (F)) 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). (Performance evaluation) A urethane-forming composition (H) was coated onto a 38 μm thick PET film using a baker-type applicator to a dry thickness of 80 μm. The mixture was then held in an explosion-proof oven set to 130°C for 5 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.

[0177] In that process, the performance of the urethane prepolymer composition (G) and the urethane-forming composition (H) was evaluated according to the following evaluation criteria. <High solid differentiation> ◎(Low VOC compliant): Non-volatile content of 99% or more, and viscosity at 25°C in the range of 1.5 to 20 Pa·s. ○ (Low VOC Pass): Excluding those with a ◎ rating, non-volatile content of 80% or more, and viscosity at 25°C in the range of 0.1 to 30 Pa·s. × (Low VOC Failure): Non-volatile content is less than 80%, or 80% or more, with a viscosity at 25°C outside the range of 0.1 to 30 Pa·s. Due to the high solid content and lack of consistent viscosity, it was determined that low VOC production is difficult. <Curability> ◎(Curing performance passed): At 130℃, it exhibits high cohesive strength immediately after curing in 5 minutes, and no adhesive residue remains on the fingers when touched. ○ (Curing performance passed): When touched immediately after curing at 130℃ for 5 minutes, adhesive residue remains on the finger. However, after aging for one week in an environment of 23℃ and 50% relative humidity after bonding with release PET, the adhesive does not spread and no adhesive residue remains on the finger when touched. × (Curing performance failure): Cures at 130°C for 5 minutes, and after aging for one week in an environment of 23°C and 50% relative humidity after bonding with release PET, the adhesive spreads, but no adhesive remains on the finger when touched. Curing is judged to be slow. ×× (Curing Failure): After curing at 130°C for 5 minutes and aging for one week in an environment of 23°C and 50% relative humidity after bonding with release PET, adhesive residue remains on the finger when touched. Insufficient curing was determined. <Moldability> ◎ (Moldability Passed): The curing performance was evaluated as ◎, and there was no repulsion during coating and curing, and the thickness variation due to flow was within 5%. ○ (Moldability Passed): The curing performance was evaluated as ○, and there was no repulsion during coating and curing, and the thickness variation due to flow was within 5%. × (Moldability Failure): The curability evaluation was ○ or higher, and the thickness variation due to flow exceeded 5%. It was judged to be prone to coating defects and liquid flow due to high temperatures during curing. ×× (Moldability Failure): Other than the above (e.g., curability evaluation is × or lower, high thixotropy index and poor coating properties). <Pot life> ◎(Pot life: remarkably good): After mixing with the hardener, the viscosity increase rate after 48 hours is 20% or less. ○ (Pot life: Good): After mixing with the hardener, the viscosity increase rate after 24 hours is 20% or less, and after 48 hours, the viscosity increase rate is more than 20%. △(Working time: normal): After mixing with the hardener, the viscosity increase rate after 10 hours is 20% or less, and the viscosity increase rate after 24 hours is more than 20%. × (Pot life failure): After mixing with the hardener, the viscosity increase rate after 10 hours exceeds 20%. Mixing and standing were performed under 23°C conditions, and viscosity was measured at 25°C using a B-type viscometer.

[0178] Compositions that meet the criteria for high solid differentiation, curability, and moldability were judged to be urethane prepolymer compositions (G) and urethane-forming compositions (H) that can differentiate into high solids at a certain viscosity, exhibit good curability, have a low environmental impact, and contribute to the formation of urethane cured products with high cohesive strength. Furthermore, those with a pot life of ◎ were judged to have a characteristically long pot life in addition to their curability, and were determined to be urethane prepolymer composition (G) and urethane-forming composition (H) that exhibit the aforementioned properties while having excellent productivity, particularly suitable for the continuous production of urethane cured products.

[0179] Furthermore, the urethane cured product (I) obtained in the above process was evaluated for its coating properties according to the following evaluation criteria, and these criteria were used as indicators of performance. <Removability> The adhesive was applied to alkali-free glass and peeled off at 300 mm / min after 20 minutes, and the peeling state was evaluated. Furthermore, Nitto Denko 31B tape was applied to the peeled adherend glass with a 5 kg roller in three passes, and after standing for 20 minutes, the peeling force was measured at 300 mm / min, and the ratio of this to the peeling force of the 31B tape on a clean glass surface was evaluated as the residual adhesion rate (31B peeling force on the glass surface after re-peeling off the urethane cured material / 31B peeling force on a clean glass surface). ◎(Removable adhesive properties passed): No visible contamination or adhesive residue, and residual adhesion rate is in the range of 90-110%. ○ (Removable adhesive properties passed): No visible contamination or adhesive residue, residual adhesion rate of less than 90% or more than 110%. Removable, and although a very small amount of a component that alters the adhesive strength remains, it is judged to be relatively good. × (Removable properties not met): If visible contamination, partial adhesive residue, or clouding is clearly present. Removable properties are deemed unsuitable due to contamination of the adherend. ×× (Curing failure): When adhesive residue is generated due to cohesive failure. <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 4Pa or higher, 2.0×10 5 Less than Pa·s. ○(Flexibility passed): 2.0×10 5 Pa·s super, 3.0×10 5 Less than Pa·s. ×(flexibility failure):3.0×10 5 Pa·s super. *In this evaluation, no test specimens with elastic moduli outside the above range were found. <Cold resistance> ◎(Cold resistance passed): Tg -80℃ or higher to -50℃ or lower. ○(Cold resistance passed): Tg over -50℃~-30℃ or less. × (Failure of cold resistance): Tg over -30℃. *In this evaluation, no specimens with glass transition temperatures (Tg) outside the above range were found. <Practical Characteristics> ◎(Practical performance meets requirements): Adhesive strength of 0.5~10N / 25mm, holding power of 24 hours or more with displacement of less than 1mm. ○ (Practical performance passing): Adhesion is between ◎ and ×, and holding power is 100 minutes or more. × (Failure to meet practical performance standards): Adhesion less than 0.1 N / 25 mm or 30 N / 25 mm, or holding power less than 100 minutes. <Ball Tack> ◎ (Possesses cohesive force and remarkably good wettability): 21 or higher ○ (Good): 6 or more and 20 or less × (normal): 5 or less Materials that meet the requirements for re-peelability, flexibility, cold resistance, and practical properties were judged to be urethane cured products (I) with excellent cohesiveness, remarkably good flexibility and cold resistance, and were judged to be urethane cured products that can be expected to be developed into urethane sheets with good adhesive properties and stain resistance when re-peeled.

[0180] Furthermore, those with a ball tack rating of ◎ were judged to possess excellent coating properties, as well as outstanding wettability in addition to cohesive force, and to exhibit characteristically high adhesive strength instantaneously. They were judged to be urethane cured products (I) and urethane sheets that exhibit various properties while having particularly good wettability to the adherend, and are especially expected to have good conformability to bending, deformation, and printing steps. <Example 1 of urethane prepolymer synthesis> Synthesis Example 1 involves mixing 100 parts by weight of polyalkylene oxide (A1) with a 10% methyl ethyl ketone solution of iron trisacetylacetonate as a urethane catalyst, using the masterbatch so that the iron trisacetylacetonate component is 0.02 parts by weight. The polyol composition is then dehydrated and desolvated under reduced pressure at 100°C for 2 hours, and an isocyanate compound (C1) is added, with the amount of hydroxyl groups derived from (A1) being (M OH ) and the amount of isocyanate groups derived from (C1) (M NCO ) is the molar ratio of (C1) M NCO / ((A1)'s M OH The reaction was carried out by raising the temperature to 70°C with a coefficient of 0.40.

[0181] 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 the NCO groups, yielding a composition containing urethane prepolymer (E1). The composition was analyzed by GPC and found to contain 32 area of ​​unreacted polyalkylene oxide (A1) and 68 area of ​​urethane prepolymer (E1) having urethane groups. The molecular weight distribution of the urethane prepolymer (E1) component was less than 1.35, indicating a remarkably narrow degree of dispersion.

[0182] Because the reaction was carried out after dehydration and solvent removal of the raw materials, the residual solvent and water content combined was less than 1000 ppm, resulting in a virtually solvent-free composition. Furthermore, the degree of unsaturation calculated from the raw materials used was a remarkably low 0.0018 meq / g. <Example 1 of manufacturing a urethane prepolymer composition and a urethane-forming composition> A urethane prepolymer composition (G1) was obtained by mixing a composition containing 68 area of ​​the urethane prepolymer (E1) synthesized in Synthesis Example 1, 32 area of ​​unreacted polyalkylene oxide (A1), 84.7% by weight of this composition, 0.3% by weight of a ketoenol tautomer compound (D1), and 15% by weight of polyalkylene oxide (B1-1) containing three hydroxyl groups.

[0183] The urethane prepolymer composition (G1) contains 42.1% by weight of polyalkylene oxide components, including polyalkylene oxide (A1) and polyalkylene oxide (B1-1) containing three hydroxyl groups. The degree of unsaturation calculated from the raw materials used was 0.0056 meq / g, indicating a remarkably low amount of monool components capable of encapsulating the ends. In addition, a volatile ketoenol tautomer compound (D1) was added at 0.3% by weight. The non-volatile content of this composition was remarkably high at 99.7% by weight, suggesting that it could be expected to have low VOCs.

[0184] The urethane prepolymer composition (G1) was analyzed by GPC and showed a bimodal distribution of the urethane prepolymer (E1) component and two polyalkylene oxide components. The combined number average molecular weight was 14,800, which is between 8,000 and 40,000, indicating a suitable molecular weight for coating with high solids content. It did not become excessively viscous even with high solids content, and a constant viscosity could be expected from room temperature to drying temperature during coating. The viscosity of the urethane prepolymer composition (G1) at 25°C was 9.6 Pa·s, indicating a constant viscosity even with high solids content, and the thixotropy index was also sufficiently low at 1.03.

[0185] A urethane-forming composition (H1) was prepared by mixing an isocyanate compound (F1) having allophanate groups in a ratio of 1.3 equivalents of NCO groups to the total amount of hydroxyl groups in the obtained urethane prepolymer composition (G1). The viscosity of the urethane-forming composition (H1) at 25°C was 8.2 Pa·s, indicating a high solids content and consistent viscosity, and excellent handling properties during coating and curing.

[0186] Furthermore, in Synthesis Example 1 and Production Example 1, iron trisacetylacetonate was added as a masterbatch using a solvent and then the solvent was removed to make it solvent-free. However, it can also be produced similarly by adding it as a powder without using a solvent and then performing dehydration and solvent removal, resulting in a urethane prepolymer composition with similar properties and a cured urethane product with similar characteristics.

[0187] (Synthesis Examples 2-16) Synthesis Examples 2-16 also involved changing various raw materials, and the synthesis and property evaluation of urethane prepolymers were carried out in the same manner as in Synthesis Example 1. Below, Table 3 shows the raw material composition and properties of compositions containing the synthesized urethane prepolymers (E) and (EC).

[0188] [Table 3]

[0189] Synthesis examples 2, 4-7, and 9, synthesized by changing various raw materials, showed remarkably low degrees of unsaturation calculated from the raw materials used, similar to synthesis example 1, and significantly fewer monool components capable of encapsulating the ends. They also contained unreacted polyalkylene oxides, and the molecular weight distribution of the urethane prepolymer (E) component having urethane groups was remarkably narrow, at less than 1.35. Compared to Synthesis Example 1, Synthesis Example 3, which had a slightly longer polymer chain with an NCO / OH ratio of 0.60, and Synthesis Example 8, which used a small amount (10 parts) of high molecular weight polyalkylene oxide (B1-1) having three hydroxyl groups and prepolymerized it with a shorter polymer chain and an NCO / OH ratio of 0.15, showed a slightly wider molecular weight distribution than Synthesis Example 1, but maintained a narrow dispersion range of less than 1.35 to 1.50.

[0190] Synthesis examples 10 and 11 are examples of chain extension using polyalkylene oxide (AC1) with a high degree of unsaturation. The high degree of unsaturation calculated from the raw materials used resulted in a broad dispersion due to by-products, which are thought to be due to the sealing of molecular ends with monool during prepolymerization. Synthesis Example 12, which primarily consisted of a polyalkylene oxide having three hydroxyl groups and was chain-extended using only polyalkylene oxide (B1-1) containing a certain amount of unsaturated monool, exhibited a broad molecular weight distribution, likely due to the influence of both the polyfunctional component and the monool. Synthesis Example 14 uses a solvent, a design based on conventional technology, and combines a relatively high molecular weight 29,000 bifunctional polyalkylene oxide (AC2) with a trifunctional polyalkylene oxide to create a high molecular weight prepolymer with enhanced cohesive strength. This design exhibits a remarkably low degree of unsaturation and is expected to provide good stain resistance at high molecular weight, but it has a broad molecular weight distribution exceeding 5.5 and low solids content.

[0191] In synthesis example 15, to achieve a lower VOC content compared to synthesis example 14, the non-volatile content was significantly increased from 30% to 80% during synthesis, resulting in a gel-like substance.

[0192] Synthesis Example 16 involves forming a first-stage NCO-terminated urethane prepolymer using relatively high molecular weight polyalkylene oxide (A1) and polyisocyanate (C2) with an NCO / OH ratio of 2.7, followed by the second stage of forming a low molecular weight polyalkylene oxide (AC) with a high hydroxyl group content and a molecular weight of 400. 3 This design significantly increases the amount of urethane groups by a two-stage polymerization method that adds a large amount of ), thereby imparting cohesive force, and uses low molecular weight polyalkylene oxide (AC) with a molecular weight of 400. 3 The composition contained 38 area of ​​) alone, and the urethane prepolymer (EC6) also had a broader molecular weight distribution than that of Synthesis Example 1.

[0193] The urethane prepolymers (E1) to (E9) used in the examples all had a relatively low average number of polyol functional groups in the range of 1.90 to 2.20, a narrow molecular weight distribution, and a weight-average molecular weight of 8000 or more. As a result, the urethane prepolymer composition (G) easily achieved both good thixotropy and a certain viscosity, and exhibited excellent moldability at high solid content.

[0194] (Manufacturing Example 1, Example 1) Example 1, which used a urethane-forming composition (H1) containing the urethane prepolymer composition (G1) obtained in Production Example 1, is shown in Table 5. It has a remarkably high non-volatile content of 99.7%, enabling low VOC reduction, a constant viscosity of 8.2 Pa·s at 25°C, a narrow molecular weight distribution of the urethane prepolymer (E1), and low thixotropy of the liquid, resulting in excellent coating properties. Due to its low degree of unsaturation, it exhibited excellent curability when volatile content was removed and curing reaction was performed in an explosion-proof oven at 130°C for 5 minutes.

[0195] Furthermore, the urethane-forming composition (H1) contains a polyalkylene oxide (B1-1) with three or more hydroxyl groups, not in a prepolymer but alone, and the molecular weight of the polyfunctional component is small. As a result, even with the use of a small amount of ketoenol tautomer compound, the viscosity increase immediately after preparation is remarkably gradual, and the viscosity increase rate after 72 hours is 20% or less, demonstrating remarkably excellent pot life.

[0196] Furthermore, the resulting urethane cured product (I1) coating film contains a polyalkylene oxide (B1-1) containing three or more hydroxyl groups alone in the urethane-forming composition, which makes it easier for the crosslinking points in the urethane cured product to detach, and because there are few unsaturated monools sealing the ends, it easily forms a loose network with few defects, and the storage modulus at 25°C is 1.0 × 10⁻⁶. 5 Despite being remarkably flexible with Pa, it was re-peelable without contamination of the adherend or leaving any adhesive residue. Furthermore, its glass transition temperature was remarkably low at -56°C, demonstrating excellent low-temperature characteristics and promising good cold resistance, which is expected to allow for impact peeling at low temperatures.

[0197] Furthermore, the urethane cured product obtained by the above design showed a remarkably high ball tack value of 32 or higher, and because it maintained cohesive force while exhibiting excellent wettability, it instantly exhibited adhesive properties to the adherend, and was a urethane cured product (I1) that was characterized by good conformability to deformation such as bending, movement, and steps.

[0198] (Manufacturing Examples 2-7, Examples 2-7) Production Examples 2-7 are examples of producing urethane prepolymer compositions (G2)-(G7) and urethane-forming compositions (H2)-(H7) by changing the type and quantity ratio of polyalkylene oxide (B) containing three or more hydroxyl groups, which is the same as in Production Example 1, while still containing the same urethane prepolymer (E1). As shown in Table 4, all of the urethane prepolymer compositions (G2)-(G7) contain polyalkylene oxide (B1) with three or more hydroxyl groups and a urethane prepolymer (E), and the sum of the unsaturated group amounts is remarkably low. The non-volatile content of these compositions is remarkably high at 99.5% by weight or more, and low VOCs can be expected.

[0199] The urethane prepolymer compositions (G2) to (G7) were analyzed by GPC and showed a bimodal to trimodal distribution of the urethane prepolymer (E) component and two polyalkylene oxide components. The combined number average molecular weight was between 8,000 and 40,000, indicating an appropriate molecular weight, preventing high viscosity even with high solids content, and allowing for a consistent viscosity from room temperature to drying temperature during coating. The viscosity of all urethane prepolymer compositions (G2) to (G7) at 25°C was in the range of 1 to 20 Pa·s, demonstrating consistent viscosity even with high solids content, and furthermore, the thixotropy index was sufficiently low at 1.2 or less.

[0200] Urethane-forming compositions (H2) to (H7) were prepared by mixing an isocyanate compound (F) with the obtained urethane prepolymer compositions (G2) to (G7) in a ratio such that the amount of NCO groups was 1.3 equivalents relative to the total amount of hydroxyl groups.

[0201] Examples 2 to 7, using urethane-forming compositions (H2) to (H7), are shown in Table 5. In all cases, the non-volatile content concentration was remarkably high at 99.5% by weight or more, enabling low VOC reduction. The viscosity at 25°C was in the range of 1 to 20 Pa·s, indicating a constant viscosity. The molecular weight distribution of the urethane prepolymer was narrow, and the liquid had low thixotropy, resulting in excellent coating properties. Due to the low degree of unsaturation, the curing properties were excellent when volatile content was removed and curing was performed in an explosion-proof oven at 130°C for 5 minutes.

[0202] Furthermore, the urethane-forming compositions (H2) to (H7) contain polyalkylene oxide (B1) with three or more hydroxyl groups, not in a prepolymer but alone, and the molecular weight of the polyfunctional component is small. As a result, despite the use of small amounts of ketoenol tautomer compounds, the viscosity increase immediately after preparation was remarkably gradual, and the viscosity increase rate after 48 hours was 20% or less, demonstrating remarkably excellent pot life.

[0203] Furthermore, the resulting urethane cured products (I2) to (I7) contain a polyalkylene oxide (B1) containing three or more hydroxyl groups in the urethane-forming composition alone, which makes it easier for the crosslinking points in the urethane cured product to detach, and because there are few unsaturated monools sealing the ends, a loose network with fewer defects is easily formed. The urethane-forming compositions (H2) to (H6) all contain 2.0 × 10⁻⁶ 5 It is flexible with a pressure of less than Pa, is re-peelable without contamination or adhesive residue, and has excellent low-temperature properties with a remarkably low glass transition temperature of -50°C or below. (H7), which contains a relatively high amount of polyalkylene oxide with three or more hydroxyl groups (50 parts by weight), showed slightly lower flexibility than (H2) to (H6), but still achieved 3.0 × 10⁻⁶ 5 It exhibits somewhat good flexibility with a Pa·s or lower, is re-peelable without contamination or adhesive residue, and has a remarkably low glass transition temperature of -50°C or lower, demonstrating excellent low-temperature properties.

[0204] The urethane cured products (I2) to (I7) obtained by the above design all exhibited high ball tack properties and excellent wettability while maintaining cohesive force. As a result, they instantly exhibited adhesive properties to the adherend, and urethane cured product (I) was characterized by its excellent conformability.

[0205] (Manufacturing Examples 8-9, Examples 8-9) Production Examples 8-9 are examples of production in which the urethane prepolymer obtained in Synthesis Example 2 (E2), which has a lower NCO / OH ratio when forming the urethane prepolymer from the prepolymer (E1) obtained in Synthesis Example 1, was used, in contrast to Production Example 1. These are urethane prepolymer compositions (G8) and (G9), and urethane-forming compositions (H8) and (H9), which have a relatively large amount of unreacted polyalkylene oxide (A1) and a low proportion of urethane prepolymer (E). As shown in Table 4, both urethane prepolymer compositions (G8) and (G9) contain polyalkylene oxide (B1) having three or more hydroxyl groups and urethane prepolymer (E), and the sum of unsaturated groups is remarkably low. The non-volatile content of these compositions is remarkably high at 99.5% by weight or more, and low VOC content can be expected.

[0206] Examples 8 and 9, using urethane-forming compositions (H8) and (H9), are shown in Table 5. In all cases, the non-volatile content concentration was remarkably high at 99.5% by weight or more, enabling low VOC reduction. However, due to the relatively high amount of unreacted polyalkylene oxide (A1) and the low ratio of urethane prepolymer (E) in the composition, the moldability in coating was slightly lower than that of (H1) to (H7). Nevertheless, the viscosity at 25°C was in the range of 1 to 20 Pa·s, indicating a constant viscosity. Furthermore, the molecular weight distribution of the urethane prepolymer was narrow, and the thixotropy of the liquid was low, resulting in generally good coating properties. Due to the low degree of unsaturation, the curability was excellent when volatile content removal and curing reaction were carried out in an explosion-proof oven at 130°C for 5 minutes.

[0207] (Manufacturing Examples 10-11, Examples 10-11) Production Examples 10-11 are examples of production in which the urethane prepolymer obtained in Synthesis Example 3, which has a slightly broader molecular weight distribution than (E1), was modified from the prepolymer (E1) obtained in Synthesis Example 1 to a urethane prepolymer (E3) with a higher NCO / OH ratio. These are urethane prepolymer compositions (G10) and (G11), and urethane-forming compositions (H10) and (H11). Table 4 shows the composition and properties. Both urethane prepolymer compositions (G10) and (G11) contain a polyalkylene oxide (B1) having three or more hydroxyl groups and a urethane prepolymer (E), and the sum of the unsaturated group amounts is remarkably low. The non-volatile content of these compositions is remarkably high at 99.5% by weight or more, and low VOC content can be expected.

[0208] Examples 10 and 11, using urethane-forming compositions (H10) and (H11), are shown in Table 5. In all cases, the non-volatile content concentration was remarkably high at 99.5% by weight or more, enabling low VOC reduction. Because the molecular weight distribution of the urethane prepolymer (E3) was slightly broader than that of (E1), the moldability in coating was slightly lower than that of (H1) to (H7). However, the viscosity at 25°C was in the range of 20 to 30 Pa·s, indicating a constant viscosity. The molecular weight distribution of the urethane prepolymer was also somewhat narrower, and the thixotropy of the liquid was low, resulting in generally good coating properties. Due to the low degree of unsaturation, the curability was excellent when volatile content removal and curing reaction were carried out in an explosion-proof oven at 130°C for 5 minutes.

[0209] [Table 4]

[0210] [Table 5]

[0211] (Manufacturing Examples 12-19, Examples 12-19) Production Examples 12 to 19 are urethane prepolymer compositions (G12) to (G19) and urethane-forming compositions (H12) to (H19), which are obtained by changing the type from the prepolymer (E1) obtained in Synthesis Example 1 to the urethane prepolymers obtained in Synthesis Examples 4 to 9, and adjusting the ratio of the amount of the polyalkylene oxide (B1) used according to the amount of the keto-enol tautomeric compound and the molecular weight of the polyalkylene oxide (B1) used in combination. Table 6 shows the composition and properties. All of the urethane prepolymer compositions (G12) to (G7) contain a polyalkylene oxide (B1) having three or more hydroxyl groups and a urethane prepolymer (E), and the total amount of unsaturated groups is significantly low. The non-volatile content concentration of this composition is significantly high at 99.5% by weight or more, and low VOC can be expected.

[0212] The urethane prepolymer compositions (G12) to (G19) were analyzed by the GPC method, showing a two- to three-peak distribution of two components, namely the urethane prepolymer (E) component and the polyalkylene oxide component. The number average molecular weight obtained by combining them was 8000 or more and less than 40000, having an appropriate molecular weight, not becoming highly viscous even at a high solid content, and a constant viscosity could be expected from room temperature to the drying temperature during coating. The viscosity of the urethane prepolymer compositions (G12) to (G19) at 25°C was in the range of 1 to 20 Pa·s, having a constant viscosity at a high solid content, and the thixotropy index was also sufficiently low at 1.2 or less.

[0213] Urethane-forming compositions (H12) to (H19) were produced by mixing an isocyanate compound (F1) at a ratio such that the amount of NCO groups was 1.3 equivalents with respect to the total amount of hydroxyl groups of the obtained urethane prepolymer compositions (G12) to (G19).

[0214] Examples 12 to 19 using the urethane-forming compositions (H12) to (H19) are shown in Table 7. All of them have a significantly high non-volatile content concentration of 99.5% by weight or more, enabling low VOC, and have a viscosity at 25°C in the range of 0.1 to 30 Pa·s, having a certain viscosity. The molecular weight distribution of the urethane prepolymer is also narrow and the thixotropy of the liquid is low, so it has excellent coating properties. Since the unsaturation is low, it has excellent curability when the volatile component removal and curing reaction are carried out in an explosion-proof oven at 130°C for 5 minutes.

[0215] Also, the urethane-forming compositions (H12) to (H19) contain a polyalkylene oxide (B1) having three or more hydroxyl groups alone rather than in the prepolymer. Since the molecular weight of the polyfunctional component is small, regardless of the amount of the keto-enol tautomeric compound used in each case, the increase in viscosity immediately after adjustment is significantly gentle, and the viscosity increase rate after 48 hours is 20% or less, showing excellent pot life.

[0216] Furthermore, the coating films of the obtained urethane cured products (I12) to (I19) contain a polyalkylene oxide (B1) having three or more hydroxyl groups alone in the urethane-forming composition. Since it is easy to leave the cross-linking points in the urethane cured product and there are few unsaturated monools that seal the ends, it is easy to form a gentle network with few defects. All of the urethane-forming compositions (H12), (H13), (H15) to (H19) are significantly flexible at 2.0×10 5 Pa or less, have no contamination or glue residue and are re-peelable, and also have a significantly low glass transition temperature of -50°C or less, showing excellent low-temperature characteristics.

[0217] In (H14) where the molecular weight of the polyalkylene oxide (B1) having three or more hydroxyl groups is short at 1900 and is relatively large at 20 parts by weight and it is easy to have more cross-linking points, the flexibility is slightly lower than that of (H2) to (H6), but it shows somewhat good flexibility at 3.0×10 5 Pa·s or less, has no contamination or glue residue and is re-peelable, and also has a significantly low glass transition temperature of -50°C or less, showing excellent low-temperature characteristics.

[0218] Furthermore, in (H16) to (H19), where the total amount of polyalkylene oxide (B) alone, including polyalkylene oxide (B1), was relatively high at 69.4-75.9% by weight, and the prepolymer (E) content was low, the high solids content and constant viscosity were observed. However, because the polyalkylene oxide component, which has a lower molecular weight than the prepolymer component, was more abundant, the liquid flowed slightly more easily during the coating and curing reaction than in (H2) to (H6). In addition, in (H16), where the amount of polyalkylene oxide (B1) having three or more hydroxyl groups was low at 1% by weight, the curability was slightly lower than in (H2) to (H6). Nevertheless, all samples showed good moldability and curability.

[0219] The urethane cured products (I12) to (I19) obtained by the above design exhibit excellent wettability while maintaining cohesive force, and all of them show remarkably high ball tack properties, instantly developing adhesive properties to the adherend, and are characterized by their high conformability.

[0220] Furthermore, both the urethane prepolymer composition (G) and the urethane-forming composition (H) obtained in the above examples did not contain a large amount of plasticizer, showed high compatibility, remained liquid and did not separate, and the cured urethane products all had a haze content of less than 2% and were highly transparent.

[0221] Furthermore, both the urethane prepolymer composition (G) and the urethane-forming composition (H) obtained in the above examples can be manufactured without intentionally including urethane catalysts or the like, and without containing 10% or more by weight of solvents as raw materials. This results in significantly lower environmental impact and a remarkably better working environment.

[0222] [Table 6]

[0223] [Table 7]

[0224] (Manufacturing Example 20, Comparative Example 1) Production Example 20 is a production example obtained by including a urethane prepolymer (E1) similar to that in Production Example 1, but without including a polyalkylene oxide (B1) having three or more hydroxyl groups, and consists of a urethane prepolymer composition (GC1) and a urethane-forming composition (HC1). Comparative Example 1, which used the urethane-forming composition (HC1), is shown in Table 9. Similar to Production Example 1, it contained a urethane prepolymer (E1) made of polyalkylene oxide with a remarkably low degree of unsaturation. The degree of unsaturation calculated from the raw materials used was 0.0018 meq / g, indicating a remarkably low amount of monool components that can encapsulate the ends. The non-volatile content was also remarkably high at 99.7% by weight. The number average molecular weight was 27,600, between 8,000 and 40,000. It had a moderate molecular weight, did not become highly viscous even with a high solid content, and a constant viscosity could be expected from room temperature to drying temperature during coating. However, because it did not contain polyalkylene oxide (B1) having three or more hydroxyl groups, it had poor curability and insufficient moldability, making it difficult to use.

[0225] Furthermore, the resulting urethane cured product (IC1) does not contain polyalkylene oxide (B1) having three or more hydroxyl groups. Therefore, although it is highly flexible, it lacks cohesive strength and leaves adhesive residue upon peeling, resulting in poor stain resistance and making it difficult to use. While it has good wettability, its cohesive strength is insufficient and its ball tack is low, so its conformability cannot be expected.

[0226] (Manufacturing Examples 21, 22, Comparative Examples 2, 3) Production Examples 21 and 22 are urethane prepolymer compositions (GC2) and (GC3), and urethane-forming compositions (HC2) and (HC3), which were prepared by adding 30% by weight and 15% by weight, respectively, of a polyalkylene oxide (BC1-1) having three or more hydroxyl groups with a high degree of unsaturation, respectively, to production Example 20 in order to impart cohesive force.

[0227] Comparative Examples 2 and 3, which used urethane-forming compositions (HC2) and (HC3), are shown in Table 9. Similar to Production Example 1, they contain a urethane prepolymer (E1) consisting of a polyalkylene oxide with a significantly low degree of unsaturation. However, they contain a large amount of polyalkylene oxide (BC1-1) having three or more hydroxyl groups with a high degree of unsaturation. As a result, the degree of unsaturation of the urethane prepolymer composition (GC2) calculated from the raw materials used exceeds 0.020 meq / g, reaching 0.027 and 0.023 meq / g respectively. These compositions contain a large amount of monool components that can encapsulate the ends, resulting in insufficient curability and moldability, making them difficult to use.

[0228] Furthermore, the resulting urethane cured products (IC2) and (IC3) had a degree of unsaturation exceeding 0.020 meq / g in the urethane prepolymer composition and contained a large amount of monool components that could seal the ends. As a result, they had poor cohesive strength and staining properties, and some adhesive residue or contamination occurred on the adherend when they were peeled off, making them difficult to use.

[0229] (Manufacturing Example 23, Comparative Example 4) Production Example 23 is a urethane prepolymer composition (GC4) and urethane-forming composition (HC4) in which, compared to Example 1 of Production Example 1, the urethane prepolymer (E1) is changed to a urethane prepolymer (E2) with a large amount of unreacted polyalkylene oxide (A1), and furthermore, a large amount of polyalkylene oxide (B1-1) having three or more hydroxyl groups is added at 50% by weight, resulting in a urethane prepolymer composition with a polyalkylene oxide (B) content exceeding 79% by weight.

[0230] Comparative Example 4 using the urethane-forming composition (HC4) is shown in Table 9. It contains a urethane prepolymer composed of a polyalkylene oxide with a significantly low degree of unsaturation, similar to that in Production Example 1. The degree of unsaturation calculated from the raw materials used is 0.0119 meq / g, and there is a small amount of a monoalcohol component that can cap the terminals. The non-volatile content concentration is also significantly high at 99.7% by weight. However, it contains more than 79% by weight of a polyalkylene oxide (B) that easily acts as a diluent, and the content of the urethane prepolymer, which easily exhibits a certain viscosity even at high temperatures, is as low as 13.4% by weight. Therefore, during the coating and curing reactions, the liquid flow was intense, the formability was poor, and it was difficult to use.

[0231] Also, the obtained urethane cured product (IC4) had good re-peelability because the degree of unsaturation in the urethane prepolymer composition (GC4) was less than 0.020 meq / g and it contained a polyalkylene oxide (B1) having three or more hydroxyl groups. However, since a large amount of the polyalkylene oxide (B) containing a large amount of the polyalkylene oxide (B1) having three hydroxyl groups was used, the characteristic of flexibility was insufficient, and it was difficult to expand to applications that require followability. The ball tackiness was also insufficient.

[0232] (Production Examples 24, 25, Comparative Examples 5, 6) Production Example 24 was produced by changing from the urethane prepolymer (E1) obtained using a polyalkylene oxide with a significantly low degree of unsaturation to the urethane prepolymer (EC1) obtained using a polyalkylene oxide with a high degree of unsaturation, compared to Example 1 of Production Example 1. They are urethane prepolymer compositions (GC5), (GC5), urethane-forming compositions (HC5), and (HC6).

[0233] Comparative Examples 5 and 6, which used urethane-forming compositions (HC5) and (HC6), are shown in Table 9. Similar to Production Example 1, they contain polyalkylene oxides (B1) having three or more hydroxyl groups with a low degree of unsaturation. However, they contain a large amount of urethane prepolymer (EC1) obtained using polyalkylene oxides with a high degree of unsaturation. As a result, the degree of unsaturation of the urethane prepolymer composition (GC5) calculated from the raw materials used exceeds 0.020 meq / g, reaching 0.1116 and 0.0452 meq / g, respectively. This indicates a high concentration of unsaturated monool components that seal the ends during crosslinking. Therefore, regardless of the type and amount of polyalkylene oxide (B1), the curability and moldability were insufficient, making them difficult to use.

[0234] (Manufacturing Example 26, Comparative Example 7) Production Example 26 is a production example containing a polyalkylene oxide (B1) having three or more hydroxyl groups, but without a urethane prepolymer (E), and consists of composition (GC7) and a urethane-forming composition (HC7). The degree of unsaturation of composition (GC7), calculated from the raw materials used, is less than 0.020 meq / g, but because it does not contain a urethane prepolymer component containing urethane groups, the number-average molecular weight of the composition is low at less than 8000, resulting in severe liquid flow during the coating and curing reaction, poor moldability, and difficulty in use.

[0235] The resulting urethane cured product (IC7) contained polyalkylene oxide (B1) with a degree of unsaturation of less than 0.020 meq / g in the urethane prepolymer composition and containing three or more hydroxyl groups, but did not contain any urethane prepolymer components. As a result, it had good re-peelability, but its flexibility and ball tack were reduced, making it difficult to apply to applications requiring conformability.

[0236] (Manufacturing Example 27, Comparative Example 8) Production Example 27 is a urethane prepolymer composition (GC8) and a urethane-forming composition (HC8) produced using a urethane prepolymer (EC2) obtained by using a polyalkylene oxide (AC1) with a high degree of unsaturation and a small amount of polyalkylene oxide (B1) with three hydroxyl groups in order to increase the average number of functional groups, and a polyalkylene oxide (B1) having three hydroxyl groups.

[0237] Comparative Example 8, which used the urethane-forming composition (HC8), is shown in Table 9. Although it contains a polyalkylene oxide (B1) with three or more hydroxyl groups and a low degree of unsaturation in the prepolymer and on its own, it contains a large amount of urethane prepolymer (EC2) obtained using a large amount of polyalkylene oxide with a high degree of unsaturation. As a result, the degree of unsaturation of the urethane prepolymer composition (GC8) calculated from the raw materials used exceeds 0.020 meq / g, reaching 0.1115 meq / g, and there is a large amount of unsaturated monool components that seal the ends during crosslinking. Therefore, even when polyalkylene oxide (B1) with three or more hydroxyl groups is used in combination with the prepolymer, the curability and moldability are insufficient, making it difficult to use. Furthermore, because the prepolymer contains a large amount of polyalkylene oxide (B1) with three or more hydroxyl groups, the molecular weight distribution is broad, and a remarkably good pot life was not achieved. The resulting urethane cured product (IC8) also lacked sufficient stain resistance and flexibility, making it difficult to apply to applications requiring re-peelability and conformability.

[0238] (Manufacturing Example 28, Comparative Example 9) Production Example 28 is a urethane prepolymer (EC3) consisting of a polyol with an average number of two functional groups using a polyalkylene oxide (B1-1) with a slightly lower degree of unsaturation, and a urethane prepolymer composition (GC9) and a urethane-forming composition (HC9) produced using a polyalkylene oxide (B1-1) with an even lower degree of unsaturation.

[0239] Comparative Example 9, which used the urethane-forming composition (HC9), is shown in Table 9. Although both the urethane prepolymer (EC3) and polyalkylene oxide (B1) had relatively low degrees of unsaturation, the overall degree of unsaturation of the urethane prepolymer composition (GC9), calculated from the raw materials used, exceeded 0.020 meq / g. This was due to the presence of an unsaturated monool component that encapsulates the ends, resulting in insufficient moldability and making it difficult to use. Furthermore, because the prepolymer contained a large amount of polyalkylene oxide (B1) with three or more hydroxyl groups, the molecular weight distribution was broad, and a remarkably good pot life was not achieved. The resulting cured urethane product (IC9) also lacked sufficient stain resistance, re-peelability, and flexibility because the overall unsaturation of the urethane prepolymer composition (GC9) exceeded 0.020 meq / g. This made it difficult to develop applications requiring re-peelability and conformability.

[0240] (Manufacturing Example 29, Comparative Example 10) Production Example 29 is a composition (GC10) and a urethane-forming composition (HC10) produced by mixing a polyalkylene oxide (A) with a remarkably low degree of unsaturation with a polyalkylene oxide (B1) having three or more hydroxyl groups, without prepolymerization. Comparative Example 10, which used a urethane-forming composition (HC10), is shown in Table 9. It contains a polyalkylene oxide with a remarkably low degree of unsaturation, and the overall degree of unsaturation calculated from the raw materials used was 0.0031 meq / g. Although it contains a remarkably small amount of monool components that can encapsulate the ends, it does not contain urethane prepolymer components, and therefore does not contain urethane prepolymer components containing urethane groups. As a result, the number-average molecular weight of the composition is low, less than 8000, leading to severe liquid flow during the coating and curing reaction, making it difficult to form a urethane cured product with a good coating appearance.

[0241] (Manufacturing Example 30, Comparative Example 11) Production Example 30 is a design based on the prior art of Synthesis Example 14, in which a solvent is used to prepolymerize a relatively high molecular weight of over 70,000 by combining a bifunctional polyalkylene oxide (AC2) with a relatively high molecular weight of 29,000 and a trifunctional polyalkylene oxide to enhance cohesive strength. It is a design that has a remarkably low degree of unsaturation and can be expected to have good stain resistance at high molecular weight, and has a broad molecular weight distribution of over 5.5, as well as a low non-volatile content concentration and is a urethane prepolymer composition (GC11) and urethane forming composition (HC11) containing a urethane prepolymer (EC5).

[0242] Comparative Example 9, which used a urethane-forming composition (HC11), is shown in Table 9. Both the urethane prepolymer (EC5) and polyalkylene oxide (B1) had significantly low degrees of unsaturation, exhibiting good curability and promising high stain resistance. However, the non-volatile content of the urethane prepolymer composition (GC11) was less than 80%, and its viscosity at 25°C was less than 0.1 Pa·s, resulting in a tendency to flow easily and making it difficult to mold to high thicknesses. Furthermore, although the non-volatile content of the urethane prepolymer composition (GC11) was adjusted to 80% by concentration, the number-average molecular weight of the urethane prepolymer composition (GC11) exceeded 70,000, resulting in a viscosity at 25°C exceeding 30 Pa·s. Similarly, the thixotropy index was also high, exceeding 1.5, resulting in a design with poor moldability, making it difficult to maintain good handling properties while achieving high solid differentiation.

[0243] (Manufacturing Example 31, Comparative Example 12) In manufacturing example 31, a relatively high molecular weight polyalkylene oxide (A1) with a significantly low degree of unsaturation and a polyisocyanate (C2) was used to form a first-stage NCO-terminated urethane prepolymer with an NCO / OH ratio of 2.7. Then, a low molecular weight polyalkylene oxide (AC) with a high hydroxyl group content and a molecular weight of 400 was added in the second stage. 3 This is a production example obtained by a two-step polymerization method that adds many ) and does not contain polyalkylene oxide (B1) having three or more hydroxyl groups, but does contain low molecular weight polyalkylene oxide (AC) with a molecular weight of 400. 3 These are urethane prepolymer compositions (GC12) and urethane-forming compositions (HC12) in which the amount of urethane groups is significantly increased to impart cohesive force.

[0244] Comparative Example 12, which used a urethane-forming composition (HC12), is shown in Table 9. It contained a urethane prepolymer (EC6) made of a polyalkylene oxide with a remarkably low degree of unsaturation. The degree of unsaturation calculated from the raw materials used was 0.0055 meq / g, indicating a remarkably low amount of monool components that can encapsulate the ends. The non-volatile content was also remarkably high at 99.7% by weight, and the curability was good. However, it contained a highly reactive low molecular weight polyalkylene oxide (AC 3The product contains a large amount of the specified component and has a relatively short pot life of less than 24 hours. Therefore, improvement would likely require increasing the amount of volatile acetylacetone or diluting it with plasticizers.

[0245] (Manufacturing Example 31, Comparative Example 12) The resulting urethane cured product (IC12) also does not contain polyalkylene oxides (B1) having three or more hydroxyl groups, but rather low molecular weight polyalkylene oxides (AC 3 Although the residual adhesion rate was slightly reduced due to the use of a large amount of ), it was still good, and the overall unsaturation of the urethane prepolymer composition (GC9) was less than 0.020 meq / g, making re-peelability possible. However, low molecular weight polyalkylene oxide (AC) 3 The material uses a large amount of the ) component and has many urethane groups, resulting in poor flexibility and glass transition temperatures exceeding -24°C and -30°C. It does not exhibit significantly better cold resistance compared to Example 1, making it difficult to use in applications requiring such properties.

[0246] [Table 8]

[0247] [Table 9]

[0248] As shown in the examples above, the urethane prepolymer composition (G) developed in this study uses a polyalkylene oxide with a certain viscosity, capable of high solid differentiation, and low unsaturated monool content. The cured urethane product exhibits high cohesive strength, good stain resistance and re-peelability, and contributes to the development of remarkably good flexibility and cold resistance. By utilizing these characteristics, it has been shown that the composition exhibits remarkably good flexibility and low-temperature properties, as well as the ability to follow changes in the shape of the adherend, making it suitable for a wide range of applications such as sealants, paints, adhesives, and bonding agents.

[0249] In particular, the urethane sheet using the urethane cured product (I) of the present invention exhibits moderate adhesive strength, re-peelability, flexibility, cold resistance, and good tackiness, making it suitable for use as a urethane adhesive. Furthermore, it is highly transparent, exhibits cohesive strength, and remarkably high flexibility and cold resistance, making it promising for applications in bending and deformation, as well as in applications involving printing steps, low-temperature environments, and re-peelability. It has been shown to be suitable for use as an optical adhesive for foldable materials and as an adhesive for biomedical applications.

Claims

1. A urethane prepolymer composition (G) comprising a hydroxyl-terminated urethane prepolymer (E) and a polyalkylene oxide (B), The urethane prepolymer (E) is a reaction product of a polyol and a polyisocyanate (C), and has at least one urethane group and at least one hydroxyl group in one molecule. Polyalkylene oxide (B) comprises polyalkylene oxide (B1) having three or more hydroxyl groups, A urethane prepolymer composition (G) having a degree of unsaturation of less than 0.020 meq / g, a number-average molecular weight calculated by gel permeation chromatography of less than 70,000, and a polyalkylene oxide (B) content in the urethane prepolymer composition in the range of 1 to 79% by weight.

2. The urethane prepolymer composition (G) according to claim 1, wherein the urethane prepolymer (E) has a molecular weight distribution of less than 1.50 as calculated by gel permeation chromatography.

3. The urethane prepolymer composition (G) according to claim 1, wherein the polyalkylene oxide (B) has a molecular weight of 700 or more and 30,000 or less, calculated from its hydroxyl value.

4. The urethane prepolymer composition (G) according to claim 1, wherein the polyalkylene oxide (B) has an unsaturation degree of less than 0.070 meq / g.

5. The urethane prepolymer composition (G) according to claim 1, wherein the non-volatile content concentration is in the range of 80 to 100% by weight and the viscosity at 25°C is in the range of 0.1 to 30 Pa·s.

6. The urethane prepolymer composition (G) according to claim 1, wherein the urethane prepolymer (E) contains alkylene oxide residues in a range of 90 to 99.9% by weight, polyisocyanate residues in a range of 0.1 to 10% by weight, and unsaturated groups in a range of 0.03% by weight or less.

7. The urethane prepolymer composition (G) according to claim 1, wherein the polyol forming the urethane prepolymer (E) comprises a bifunctional polyalkylene oxide (A) having a degree of unsaturation of less than 0.010 meq / g and a number average molecular weight calculated from the hydroxyl value in the range of 3,000 to 10,000.

8. The urethane prepolymer composition (G) according to claim 1, wherein the average number of functional groups fave of the total polyols forming the urethane prepolymer (E) is in the range of 1.85 to 2.

20.

9. The urethane prepolymer composition (G) according to claim 7, wherein the polyalkylene oxide (A) forming the urethane prepolymer (E) contains a primary hydroxyl group.

10. The urethane prepolymer composition (G) according to claim 1, wherein the polyisocyanate (C) comprises any aliphatic isocyanate, an alicyclic isocyanate, or a modified thereof, and forms a urethane prepolymer (E), wherein the average number of functional groups fave of the total polyisocyanates is in the range of 1.90 to 2.

79.

11. The urethane prepolymer composition (G) according to claim 1, comprising 0.01 to 1.0% by weight of a ketoenol tautomer compound (D).

12. A urethane-forming composition (H) comprising a urethane prepolymer composition (G) according to any one of claims 1 to 11 and an isocyanate compound (F).

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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