JP2023155601A - Urethane prepolymer composition - Google Patents

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

The present disclosure relates to urethane prepolymer compositions.

Adhesives are used, for example, in tapes, labels, stickers, decorative sheets, anti-slip sheets, double-sided adhesive tapes, etc.In recent years, adhesives have been used in various applications such as adhesives for liquid crystal displays and touch panels of computers, televisions, mobile phones, etc. used in the field.

As adhesives, for example, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, oxyalkylene adhesives, etc. are known. Acrylic adhesives tend to be used in a wide range of applications, from mold adhesives to slightly adhesive adhesives with minute adhesive strength.

However, acrylic adhesives pose problems such as odor, skin irritation, and contamination of the base material when the acrylic monomer remains in the adhesive. Furthermore, after acrylic adhesives are applied to an adherend, their adhesive strength tends to increase and their migration properties tend to increase due to changes over time. Therefore, there is a problem that adhesive residue is likely to be left on the adherend and removability is likely to be insufficient. In addition, acrylic pressure-sensitive adhesives use comonomers with a high glass transition temperature in order to develop cohesive force, which causes problems such as insufficient impact resistance at low temperatures and poor cold resistance.

On the other hand, urethane adhesives have a lower molecular weight than acrylic adhesives and have the advantage of being able to easily follow changes in the shape of the adherend.

On the other hand, polyalkylene oxides containing large amounts of by-product monools having an unsaturated group at one end (hereinafter referred to as unsaturated monools) and urethane prepolymers using the same are used as raw materials for polyurethane. However, polyalkylene oxides containing large amounts of unsaturated monools and urethane prepolymers using them have the problem of slow curing (solidification) due to reaction with isocyanate compounds, which impairs productivity. arise.

Patent Document 1 discloses a urethane-forming composition that uses a polyalkylene oxide with a narrow molecular weight distribution and significantly less unsaturated monool, has low viscosity, has excellent handling properties, and has high curability when producing a urethane adhesive. and prepolymers thereof. By using these polyalkylene oxides, the problem of curability faced by polyalkylene oxides containing a large amount of unsaturated monools is improved, and the stain resistance upon re-peeling is improved. However, there was also a desire to ensure a certain viscosity in terms of coatability and to have a high solidity fraction in order to reduce VOC.

Patent Document 2 discloses a hydroxyl group-terminated urethane prepolymer solution having a solid content concentration of 80% by mass or more and a constant viscosity of 800 to 8000 mPa·s, which is composed of a polyol such as a polyalkylene oxide with a somewhat low degree of unsaturation and an isocyanate. has been done. However, since cohesive strength is imparted by a two-stage polymerization method in which a low molecular weight polyol with a molecular weight of 600 or less and a large amount of hydroxyl groups is added in the second stage after forming an NCO group-terminated urethane prepolymer, the resulting cured urethane product In some cases, the adhesive tends to become hard due to an increase in the number of urethane groups in the adhesive, or the glass transition point tends to increase due to the influence of low molecular weight polyols, etc. It was a design that could not be expected to have significantly good low-temperature properties derived from the significantly low glass transition point of the polyether skeleton, and the resulting urethane pressure-sensitive adhesive had low adhesive strength. Further, if the polyol contains a large amount of plasticizer and low molecular weight polyol remains unreacted, there is a concern that it may bleed.

Therefore, we use polyalkylene oxide that has a certain viscosity, can be highly solidified, and has a low amount of unsaturated monool, and the urethane cured product has cohesive strength, a urethane that contributes to the expression of significantly good flexibility and cold resistance. A prepolymer composition was needed.

Patent No. 6891412 WO2020-230648

One aspect of the present invention is directed to providing urethane prepolymer compositions that are conducive to forming polyurethanes that have high cohesive strength and have significantly better flexibility and cold resistance.

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

Yet another aspect of the present invention is directed to providing a polyurethane adhesive comprising the polyurethane.

As a result of intensive studies to solve the above problems, the present inventors have surprisingly found that by combining a prepolymer with a specific composition and a specific polyol in a specific ratio, it is possible to achieve high solid fractionation with a moderate viscosity. Therefore, the present inventors have discovered a urethane prepolymer composition that contributes to the formation of a cured urethane product that exhibits significantly high flexibility and cold resistance, and is capable of exhibiting high cohesive strength, and has completed the present invention.

That is, each aspect of the present invention is [1] to [14] shown below.
[1] A urethane prepolymer composition (G) containing a hydroxyl group-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,
The polyalkylene oxide (B) contains a polyalkylene oxide (B1) having three or more hydroxyl groups,
The degree of unsaturation of the urethane prepolymer composition (G) is less than 0.020 meq/g, the number average molecular weight calculated by gel permeation chromatography method is less than 70,000, and the polyalkylene oxide ( A urethane prepolymer composition (G) in which the content of B) is in the range of 1 to 79% by weight.
[2] The urethane prepolymer composition (G) according to [1] above, wherein the urethane prepolymer (E) has a molecular weight distribution calculated by gel permeation chromatography of 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 a 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 degree of less than 0.070 meq/g.
[5] The urethane preform according to any one of [1] to [4] above, which has a nonvolatile 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. Polymer composition (G).
[6] 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. The urethane prepolymer composition (G) according to any one of [1] to [5] above, containing 03% by weight or less.
[7] The polyol forming the urethane prepolymer (E) is a difunctional polyalkylene oxide (A ) The urethane prepolymer composition (G) according to any one of [1] to [6] above.
[8] The urethane prepolymer according to any one of [1] to [7] above, which forms the urethane prepolymer (E) and has an average functional group number fave of all polyols in the range of 1.85 to 2.20. Composition (G).
[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]
The polyisocyanate (C) contains an aliphatic isocyanate, an alicyclic isocyanate, or a modified product thereof, and the average number of functional groups fave of all the polyisocyanates forming the urethane prepolymer (E) is 1.90 to 2. The urethane prepolymer composition (G) according to any one of [1] to [9] above, which has a molecular weight in the range of 79.
[11] The urethane prepolymer composition (G) according to any one of [1] to [10] above, which contains the ketoenol tautomer compound (D) in a range of 0.01 to 1.0% by weight.
[12]
A urethane-forming composition (H) comprising the urethane prepolymer composition (G) according to any one of [1] to [11] above and an isocyanate compound (F).
[13]
A cured urethane product (I) containing a reactant of the urethane-forming composition (H) described in [12] above.
[14]
A urethane adhesive comprising the cured urethane product (I) according to [13] above.

The urethane prepolymer composition, which is one aspect of the present invention, can be highly solidified with a constant viscosity, making it possible to reduce VOC. It has excellent coating properties due to its resistance to liquid flow, and has good moldability by proceeding with curing (solidification) due to the reaction with isocyanate compounds without using large amounts of urethanization catalysts. Furthermore, it has high transparency. A sticky cured urethane product with high cohesive force can be obtained.

The cured urethane product, which is an embodiment of the present invention, has excellent cohesive force and strength, and can be expected to improve the stain resistance of adherends during re-peeling. It can be expected to follow the movement and shape changes of the material, and has remarkably good low-temperature properties, making it suitable for a wide range of applications such as sealants, paints, pressure-sensitive adhesives, and adhesives.

Among these, the urethane adhesive using the cured urethane product, which is one aspect of the present invention, has moderate adhesive strength and exhibits removability and good tackiness, so it is characterized by wettability to adherends. It can be suitably used as a removable adhesive. Furthermore, it is highly transparent, exhibits cohesive strength, high flexibility, and low-temperature properties, so it can be expected to be used in bending, deformation, movement tracking, printing step tracking, and applications in low-temperature environments. It can be suitably used as a biological adhesive.

Exemplary embodiments for carrying out the invention will be described in detail below.
<Urethane prepolymer composition (G)>
The urethane prepolymer composition (G) which is one aspect of the present invention is a urethane prepolymer composition (G) containing a hydroxyl group-terminated urethane prepolymer (E) and a polyalkylene oxide (B),
The polyalkylene oxide (B) contains a polyalkylene oxide (B1) having three or more hydroxyl groups,
The polyalkylene oxide ( The content of B) is in the range of 1 to 79% by weight.

If the number average molecular weight of the urethane prepolymer composition (G) calculated by gel permeation chromatography is 70,000 or more, the cohesive force of the cured urethane product is likely to increase, but gelation and insoluble matter formation may occur during urethane prepolymer synthesis. As a result, stable production requires dilution and concentration with a solvent, and the viscosity and thixotropy index tend to increase, making it difficult to achieve high solidity with a constant viscosity and handling. Therefore, it becomes difficult to reduce VOC due to high solid differentiation.

In addition, when the degree of unsaturation of the urethane prepolymer composition (G) is 0.020 meq/g or more, the urethane prepolymer (E) and polyalkylene oxide (B) contain a large amount of unsaturated groups. When forming a cured product, the ends are easily sealed and a low molecular weight product is easily formed, resulting in poor curability, reduced cohesive force, and poor stain resistance and removability, making it difficult to use. In addition, if the amount of urethane groups or crosslinking components is increased to compensate for this, the cured urethane product will become hard, making it difficult to develop remarkable flexibility, and the low-temperature properties will likely deteriorate. Difficult to adapt to applications that require specific characteristics.

In addition, when the weight ratio of the polyalkylene oxide (B) in the urethane prepolymer composition (G) is less than 1% by weight, or when the polyalkylene oxide (B) has a polyalkylene oxide (B1) having three or more hydroxyl groups, If it is not contained, the resulting cured urethane will lack cohesive strength and removability will deteriorate, making it difficult to use. If the weight ratio exceeds 79% by weight, the resulting cured urethane will not stably reach the desired level. It is difficult to use because it does not exhibit flexibility, and when curing urethane, the reaction tends to proceed unevenly, which may easily deteriorate the appearance of the coating film.

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, but gelation and insoluble matter formation are less likely to occur during urethane prepolymer synthesis. The number average molecular weight is preferably less than 60,000 because the amount of solvent and concentration during production can be further reduced and the VOC reduction effect is high.
Among these, it is easy to maintain a constant viscosity even with high solidification, and molding defects due to liquid flow can be further suppressed, and the resulting cured urethane product is more likely to stably exhibit high cohesive strength, so the number average molecular weight is It is preferably 6,000 or more and less than 50,000, most preferably 8,000 or more and less than 40,000. Note that the number average molecular weight of the urethane prepolymer composition (G) calculated by gel permeation chromatography is measured in the same manner as for polyalkylene oxide, which will be described later. The number average molecular weight was calculated by excluding components with a molecular weight of 600 or less, such as solvents, ketoenol tautomer compounds, phenolic antioxidants, and other additives with a molecular weight of 600 or less.

Further, the molecular weight distribution of the urethane prepolymer composition (G) is expressed by the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), and is usually preferably less than 10, but Preferably, the thixotropy index is in the range of 1.1 to less than 3.0, most preferably 1. It is in the range of .3 to less than 2.0. In particular, it contains a relatively high molecular weight urethane prepolymer component that tends to develop appropriate viscosity and a relatively low molecular weight urethane group that includes trifunctional or higher functional polyalkylene oxide (B1) that tends to exhibit better curability. It is preferable to exhibit bimodality or more consisting of a polyalkylene oxide component containing no urethane group, and more preferably to exhibit bimodality or more consisting of a polyol component containing no urethane group when forming the urethane prepolymer. . By creating bi- or tri-modal properties using a relatively high molecular weight urethane prepolymer component and a polyalkylene oxide component containing trifunctional or higher functional polyalkylene oxide (B1), it has an appropriate viscosity and a lower thixotropy index, making it easy to handle. It is preferable because it has excellent properties and exhibits high curability, making it easier to form a cured urethane product with better productivity.

In addition, the molecular weight distribution of the urethane prepolymer composition (G) is similar to the calculation of the number average molecular weight. The components were excluded from the calculation.

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; /g or less, more preferably 0.010 meq/g or less, and most preferably 0.0001 to 0.009 meq/g. In this embodiment, the content of unsaturated groups was measured in the same manner as for polyalkylene oxide (A) described below.

The content of polyalkylene oxide (B) 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 since it is easier to achieve both high cohesive force and high flexibility. , is preferably in the range of 5 to 70% by weight, and more preferably has a moderate viscosity, which facilitates stable coating properties regardless of the crosslinking conditions, and facilitates achieving both high cohesive force and high flexibility. It ranges from 10 to 60% by weight, most preferably from 20 to 55% by weight. The ratio was determined by gel permeation chromatography analysis of the urethane prepolymer composition (G) to determine the difference between the peak derived from the polyalkylene oxide (B) and the relatively high molecular weight peak derived from the urethane prepolymer (E). In some cases, it can be calculated from the area ratio, and the weight ratio may be used instead.

In addition, it may contain a single polyol component that does not contain a urethane group, such as a polyol component that remained during the formation of the urethane prepolymer (E), and although it is included in the polyalkylene oxide (B), it has a higher cohesive force and higher flexibility. In order to be compatible, 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, more preferably 1. It ranges from 5 to 45% by weight. Among these, the range of 2 to 35% by weight is more preferable, and the most preferable is 2 to 35% by weight, because it is easy to achieve stable coating properties regardless of the crosslinking conditions, and it is easy to achieve both high cohesive force and high flexibility. ~30% by weight. Note that the ratio may be calculated by performing various structural analyzes such as NMR of the fractionated components and determining the proportion in the polyalkylene oxide (B).

In particular, when the molecular weight of polyalkylene oxide (B) is low, it is easier to achieve both high cohesive force and high flexibility when the weight ratio of polyalkylene oxide (B) is low; In this case, the higher the weight ratio of polyalkylene oxide (B), the easier it is to achieve both high cohesive force and high flexibility, so the number average molecular weight and weight ratio calculated from the hydroxyl value of polyalkylene oxide (B) are as follows: It is preferable that the formula is satisfied.
Number average molecular weight of (B)/2000<weight ratio of (B)<number average molecular weight of (B)/50
(1≦(B) weight ratio≦79)
Among these, it is more preferable to satisfy the following general formula because it is 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, the crosslinking reaction proceeds more uniformly, making it easier to mold with a beautiful coating appearance, and maintaining flexibility and stably exhibiting physical properties such as durability regardless of environmental conditions. It is more preferable to satisfy.
Number average molecular weight of (B)/750<weight ratio of (B)<number average molecular weight of (B)/200
(10≦(B) weight ratio≦60)
The preferred weight ratio of the polyalkylene oxide (B) is that the relationship between the ratio of the polyalkylene oxide (B1) having three or more hydroxyl groups in the urethane prepolymer composition (G) and the number average molecular weight is also within the above range. It is preferable for the same reason as above, and it is preferable that the following general formula is satisfied.
Number average molecular weight of (B1)/2000<weight ratio of (B1)<number average molecular weight of (B1)/50
(1≦(B1) weight ratio≦50)
Among these, it is more preferable to satisfy the following general formula because it is 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, the crosslinking reaction proceeds more uniformly, making it easier to mold with a beautiful coating appearance, and maintaining flexibility and stably exhibiting physical properties such as durability regardless of environmental conditions. It is more preferable to satisfy.
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 the urethane prepolymer (E) in the urethane prepolymer composition (G) is not particularly limited, but is in the range of 10 to 90% by weight since it is easier to achieve both high cohesive force and high flexibility. It is preferable that the amount is in the range of 20 to 85% by weight, and more preferably it is in the range of 20 to 85% by weight, because it has a moderate viscosity and tends to have excellent coating properties in a stable manner regardless of the crosslinking conditions, and it is easy to achieve both high cohesive force and high flexibility. The most preferred range is 40-80% by weight. The ratio was determined by gel permeation chromatography analysis of the urethane prepolymer composition (G) to determine the difference between the peak derived from the polyalkylene oxide (B) and the relatively high molecular weight peak derived from the urethane prepolymer (E). In some cases, it can be calculated from the area ratio, and the weight ratio may be used instead.

The urethane prepolymer composition (G) contains alkylene oxide residues because the wettability of the resulting cured urethane product tends to be significantly improved, and it also tends to exhibit a characteristically low glass transition point and has excellent low-temperature properties. The content is preferably 60% by weight or more, more preferably 80 to 99.9% by weight, and most preferably 95 to 99.8% by weight. The content of each residue can be calculated by NMR method or the like, but it may also be calculated by separating each component, performing alkaline decomposition, etc., and analyzing each fraction, if necessary. Further, when each raw material in the composition is known, it may be calculated from the charging ratio of each raw material and the content rate of alkylene oxide residue in each raw material. For example, from the number average molecular weight calculated from the hydroxyl value of the polyalkylene oxide (A) used to form the urethane prepolymer (E) and the polyalkylene oxides (B) and (B1) to be mixed, each initiator residue and It may be calculated from the alkylene oxide residue content calculated by dividing the saturated group content and the charging ratio of each raw material.

Further, the alkylene oxide residue is not particularly limited, and for example, alkylene oxide residues having 2 to 20 carbon atoms can be used, but the urethane prepolymer composition (G) tends to be liquid and highly transparent, Since it is easy to obtain a cured urethane product with good mechanical properties, it is preferable to contain an alkylene oxide residue having 2 to 3 carbon atoms, and examples of more preferable alkylene oxide residues include propylene oxide residue, ethylene oxide residue, etc. Most preferred is a propylene oxide residue.

Among these, it is preferable that the urethane prepolymer composition (G) contains 70% by weight or more of propylene oxide residue, more preferably 90 to 99.9% by weight, since it is easy to improve the mechanical properties of the cured urethane product. , most preferably in the range of 95 to 99.8% by weight. In addition, it may contain an ethylene oxide residue because it tends to improve the heat and humidity resistance, and when it is included, it is preferably contained in an amount of 0.1% by weight or more, and more preferably, the cohesive force after the heat and humidity conditions is The amount is preferably 0.5 to 15% by weight, and most preferably 1 to 13% by weight since it is easy to maintain adhesive strength.

In particular, the urethane prepolymer composition (G) should contain a polyalkylene oxide structure with a number average molecular weight of 3000 or more, since the resulting cured urethane product tends to exhibit significantly better wettability and low-temperature properties. is preferable, and it is particularly preferable to include a bifunctional polyalkylene oxide structure having a number average molecular weight of 3000 or more. The content of the polyalkylene oxide structure having a number average molecular weight of 3000 or more is not particularly limited, but it is preferably contained in the urethane prepolymer composition (G) at 50% by weight or more, more preferably from 70 to 99.9% by weight. most preferably in the range of 95 to 99.8% by weight.

In addition, since the resulting cured urethane product tends to exhibit significantly better low-temperature properties and flexibility, the amount of residue derived from a low molecular weight polyol with a molecular weight of 600 or less is preferably in the range of 25% by weight or less. , more preferably 4% by weight or less, and most preferably not intentionally included.

Furthermore, if it remains during the formation of a cured urethane product, it is likely to cause contamination due to bleeding, so the residue derived from a low molecular weight polyol with a molecular weight of 300 or less is preferably in the range of 10% by weight or less; Preferably it is 1.5% by weight or less, and most preferably it is not intentionally included.

In addition, although not particularly limited, since they tend to exhibit significantly higher ball tack properties and wettability, aromatic structures such as aromatic amine residues, sugar residues with 6 or more carbon atoms, polyester residues, polyoxytetra The content of methylene residues and polycarbonate residues is preferably 20% by weight or less, more preferably 5% by weight or less, and most preferably not intentionally included. Note that the preferred content range of the above structure does not include the above structure in additives that are non-reactive with isocyanates such as solvents that are removed by volatilization such as benzene and toluene, and ester plasticizers. Although the alicyclic structure is not particularly limited, it is preferably in the range of 20% by weight or less, more preferably 5% by weight or less, and most preferably is intentionally not included.

Although not particularly limited, the urethane prepolymer composition (G) contains: The polyisocyanate residue is preferably contained in a range of 0.1 to 20% by weight, more preferably in a range of 0.3 to 10% by weight. Among these, while maintaining the cohesive strength of the resulting cured urethane product, the viscosity does not easily increase when mixed with a crosslinking agent even when the ketoenol tautomer compound is contained in a small amount of 1.0% by weight or less, resulting in a characteristically long pot life. Since it is easy to develop, the amount is 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.

Furthermore, the polyisocyanate residue preferably includes a bifunctional or more functional polyisocyanate residue, such as an aliphatic polyisocyanate residue, an alicyclic polyisocyanate residue, an aromatic polyisocyanate residue, or a modified product thereof. For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine, etc. Diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tetramethylxylylene 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 Examples include residues of isocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, and residues of modified products thereof. Among these, aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, or these It is preferable that the polyisocyanate contains a residue of a modified product, and more preferably it is an aliphatic polyisocyanate residue or a modified product thereof, since it is easy to obtain a cured urethane product that is significantly flexible while maintaining high cohesive strength. is more preferable. In addition, the residue of the modified polyisocyanate is not particularly limited, but may include a urethane group, a carbodiimide group, an allophanate group, a urea group, a biuret group, an isocyanurate group, an amide group, an imide group, a uretonimine group, a uretdione group, or Examples include residues of modified products containing oxazolidone groups and 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 and nurate/allophanate modification, can also be suitably used. Among these, when using a modified product, it is preferable to include one or more of urethane-modified and allophanate-modified structures because it tends to exhibit significantly good wettability.

The content of each residue in the urethane prepolymer composition (G) may be determined by decomposing it into each raw material by Kolish decomposition or alkaline decomposition as necessary, and determining the composition ratio of each raw material. If it is known, it may be calculated from the charging ratio and the proportion of each raw material in the chemical structure.

The viscosity of the urethane prepolymer composition (G) at 25°C is not particularly limited, but it should be in the range of 0.1 to 30 Pa·s because it is less likely to flow and can be uniformly formed into thin to thick films. is preferably in the range of 1.5 to 20 Pa·s, and most preferably in the range of 3 to 15 Pa·s. In particular, it maintains a constant viscosity even when volatile components are volatilized or heated during the drying process, which prevents molding defects such as liquid flow and voids occurring during the coating and curing process, and increased thickness at the coating end. Since it is difficult to generate, it is preferable that the non-volatile content is 80% or more and the temperature is in the range of 0.1 to 30 Pa・s, and more preferably the non-volatile content is 99% or more and the temperature is in the range of 1.5 to 20 Pa・s, although it is not particularly limited. Most preferably, the nonvolatile content is 99% or more and the pressure is in the range of 3 to 15 Pa·s. Furthermore, for the same reason, 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 20 Pa·s. The range is 10 Pa·s. Further, it is preferable that it is a uniform liquid at 0 to 25°C and that there is no separation upon standing.

Further, although not particularly limited, it is preferable that the fluidity of the liquid is always high because actual coating becomes easier, and the thixotropy index (TI value) is preferably 1.5 or less, more preferably 1.3 or less. and is most preferably in the range of 1.0 to 1.2. The thixotropy index (TI) was determined using a B-type viscometer and spindle No. 25°C. 21, and calculated according to the following formula.
TI = 1.2 rpm viscosity / 12 rpm viscosity When the viscosity and thixotropy index are in this range, when the urethane prepolymer composition (G) is mixed with the isocyanate compound (F) to form the urethane-forming composition (H). It is easy to mix uniformly with the liquid, and the defoaming operation is easy, so it has excellent handling properties, and when applied with a coating machine, good coating properties can be obtained, making it easy to handle.

The urethane prepolymer composition (G) has good visibility, making it easy to find foreign substances, and the obtained cured urethane product also tends to be transparent, so it is preferably visually transparent. Among these, 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. Note that the haze value of the urethane prepolymer composition (G) may be calculated by applying it to a PET base material or the like and dividing the haze value for the base material.

The urethane prepolymer composition (G) can contain other active hydrogen compounds in addition to the urethane prepolymer (E) and the polyalkylene oxide (B), and is not particularly limited. For example, in order to further improve the wettability of the cured urethane product, polyalkylene oxide having two hydroxyl groups or polyalkylene oxide having one hydroxyl group may be included, and polyoxytetramethylene glycol may be added to impart cohesive force. It can contain polyols different from polyalkylene oxides such as polyester polyols, polycarbonate polyols, amine-initiated polyols, sugar-initiated polyols having 4 or more carbon atoms, amino alcohols, polyamines, and the like. Further, in order to impart heat-and-moisture resistance, a polyalkylene oxide having one or more hydroxyl groups and an ethylene oxide residue can be included. Among these, a polyalkylene oxide having two hydroxyl groups and a molecular weight of 3,000 or more may be used in combination, which is preferred, in order to further improve wettability while maintaining low-temperature properties and removability.

When containing other active hydrogen compounds in addition to the urethane prepolymer (E) and polyalkylene oxide (B), it is easier to maintain and improve better wettability and removability, so the content is in the range of 45% by weight or less. It is preferable. Among these, the content is preferably 25% by weight or less, more preferably 8% by weight or less, and most preferably 0.01 to 4% by weight, excluding the residue of the polyol forming the urethane prepolymer (E). is within the range of

On the other hand, if it remains during the formation of a cured urethane product, it may easily cause contamination due to bleeding, so the content of the low molecular weight polyol with a molecular weight of 300 or less is preferably 10% by weight or less, more preferably 1% by weight or less. .5% by weight or less, and most preferably intentionally not included.

The urethane prepolymer composition (G) contains as additives a ketoenol tautomer compound, an acid retarder, other retarders, a urethanization catalyst, an antistatic agent, a plasticizer, an antioxidant, a leveling agent, a solvent, and a chain extender. , fillers, stabilizers, and other additives.

Among them, although not particularly limited, it is preferable that the urethanization catalyst etc. does not contain tin compounds in an amount of 1000 ppm or more, more preferably 50 ppm or more, and most preferably intentionally, because of the large environmental burden. It is not included in Further, although there is no particular limitation, it is preferable that the solvent is not contained in an amount of 30% by weight or more, and more preferably not in an amount of 10% by weight or more because of the large burden on the environment. Among them, it is preferable not to contain more than 5% by weight, and more preferably not more than 1% by weight, since it has a significantly small burden on the environment and also tends to significantly improve the working environment. In this embodiment, the solvent does not contain volatile additives such as ketoenol tautomer compounds with a boiling point of 200°C or less, but the volatile compounds, including volatile additives, are 1% by weight or more. It is most preferable not to contain it, and the urethane prepolymer composition (G) of the present invention can easily be obtained with such properties.

The method for producing the urethane prepolymer composition (G) is not particularly limited, but for example, the urethane prepolymer (E) with a hydroxyl group terminal is formed in advance at a temperature in the range of room temperature to 150°C, and the polyalkylene oxide composition is prepared at an arbitrary temperature. A method of mixing (B) and additives as necessary is to form a hydroxyl-terminated urethane prepolymer (E) at a temperature in the range of room temperature to 150°C in a state where it is mixed with additives in advance, and then to form a polyurethane prepolymer at an arbitrary temperature. It can be adjusted by a method of mixing alkylene oxide (B) and other additives as necessary. Further, in order 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 forming the urethane prepolymer (E). Furthermore, when adding polyalkylene oxide (B) before or during the formation of the hydroxyl-terminated urethane prepolymer (E), the thixotropy index of the urethane prepolymer composition (G) increases, making it difficult to coat. However, it is preferable to add the polyalkylene oxide (B) after the urethane prepolymer (E) is formed, since gel-like substances and insoluble matters may be easily formed. A portion may be added in advance to cause a concerted reaction, and there is no particular limitation.

The nonvolatile content concentration of the urethane prepolymer composition (G) is not particularly limited, but it is usually in the range of 10 to 100% by weight since it is easy to obtain good coating properties when coating with a coating machine. , preferably in the range of 50 to 100% by weight.

Among these, the urethane prepolymer composition (G) of the present invention has excellent coatability without becoming too high in viscosity even at a high solid content because the molecular weight of the urethane prepolymer (E) is low, and also has excellent coatability due to the low molecular weight of the urethane prepolymer (E). Because it mainly contains alkylene oxide (B) as a mixture rather than within the molecule, it is easy to achieve a long pot life even with a high solids content, and even with a small amount of ketoenol tautomer compound used, a significantly long pot life can be achieved. Because of its easy-to-use characteristics, higher solid fractionation is possible and low VOC characteristics are more easily expressed, the nonvolatile content concentration of the urethane prepolymer composition (G) can be more preferably used in the range of 80 to 100% by weight. More preferably, the content is in the range of 95 to 100% by weight, which makes it easier to take advantage of the feature of longer pot life, and most preferably in the range of 99 to 99.9% by weight.

In addition, although not particularly limited, since the urethane prepolymer composition (G) of the present invention has the characteristic that it can be easily differentiated into solids without using many additives, the urethane prepolymer (E) and polyalkylene oxide (B) and other polyols are preferably contained in an amount of 70 to 100% by weight, more preferably 80 to 100% by weight.
<Urethane prepolymer (E)>
Urethane prepolymer (E) is a reaction product of polyol and polyisocyanate (C), and refers to a compound having at least one urethane group and at least one hydroxyl group in one molecule. or a thiourethane group. Among these, 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 have any hydroxyl group in one molecule, it is difficult to use because the cohesive force does not increase even if a crosslinking agent such as polyisocyanate is used and the desired cured urethane product cannot be obtained. Moreover, when it has an isocyanate group instead of a hydroxyl group, it is difficult to use because the reaction tends to proceed due to moisture in the air and stable production is difficult. Furthermore, if there is no urethane group in one molecule, it is difficult to develop the desired viscosity and the moldability is poor, and the cohesive strength of the resulting cured urethane product tends to decrease, making it difficult to use.

The molar ratio (M _NCO /M _OH ) of the sum of NCO groups possessed by the polyisocyanate (M _NCO ) to the sum of hydroxyl groups possessed by the polyol (M _OH ) forming the urethane prepolymer (E) is less than 1.0. It is preferable that the urethane prepolymer composition (G) has a good storage stability and is easy to obtain as a hydroxyl group terminal, and it is easy to form a urethane that stably has an excellent coating film appearance. Among these, urethane-forming compositions that tend to exhibit a low thixotropy index (TI value), are less likely to generate gel-like substances or insoluble matters, tend to have a constant viscosity, and have good coating properties regardless of conditions ( In order to easily obtain H), the molar ratio (M _NCO /M _OH ) of the sum of NCO groups possessed by the polyisocyanate (M _NCO ) to the sum of hydroxyl groups possessed by the polyol (M _OH ) is 0.05 or more and 0.69 It is preferably the following, more preferably 0.10 or more and 0.49 or less, and most preferably 0.15 or more and 0.45 or less.

The urethane prepolymer (E) preferably contains an alkylene oxide residue, a polyisocyanate residue, and an unsaturated group of 0.010 meq/g or less as constituent components.

The content of unsaturated groups in the urethane prepolymer (E) is not particularly limited, but it is preferably 0.010 meq/g or less because the strength and cohesive force of the resulting polyurethane tend to be high, and 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 below.

The content of alkylene oxide residue in the urethane prepolymer (E) is determined because the wettability of the resulting cured urethane product tends to be markedly good and it tends to exhibit a characteristically low glass transition point. The content of the group is preferably 70% by weight or more, more preferably 90 to 99.9% by weight, and most preferably 95 to 99.8% by weight. Further, the alkylene oxide residue is not particularly limited, but for example, alkylene oxide residues having 2 to 20 carbon atoms can be used, but the urethane prepolymer composition tends to be liquid and highly transparent, and has good mechanical properties. Since it is easy to obtain a cured urethane product with good physical properties, it is preferable to contain an alkylene oxide residue having 2 to 3 carbon atoms, and examples of more preferable alkylene oxide residues include propylene oxide residue and ethylene oxide residue.
Among these, it is preferable that the urethane prepolymer (E) contains 70% by weight or more of propylene oxide residue, more preferably 90 to 99.9% by weight, and most preferably The preferred range is 95 to 99.8% by weight. In addition, it may contain ethylene oxide residue because it tends to improve the heat and humidity resistance, and when containing it, the content is preferably 0.1% by weight or more, more preferably 1 to 20% by weight, and most preferably It ranges from 5 to 18% by weight.

Among these, the urethane prepolymer (E) preferably contains a polyalkylene oxide structure having a number average molecular weight of 3000 or more, since the resulting cured urethane product tends to exhibit significantly better wettability and low-temperature properties. The content of the polyalkylene oxide structure having a number average molecular weight of 3000 or more is not particularly limited, but it is preferably contained in the urethane prepolymer (E) at 60% by weight or more, more preferably from 80 to 99.9% by weight. , most preferably in the range of 95 to 99.8% by weight. Among these, the polyalkylene oxide structure having a number average molecular weight of 3000 or more is preferably a residue of a polyol having two hydroxyl groups.

In addition, it is easier to shorten and suppress the induction period at the initial stage of the reaction when forming the urethane prepolymer, and it is easier to suppress overshoot due to heat generation, resulting in stable quality and improved productivity, which reduces the burden on the environment. It is preferable that the urethane prepolymer (E) has a residue of a primary hydroxyl group because it is easy to use. Among these, it is preferable that a polyalkylene oxide with relatively low reactivity and a number average molecular weight of 3000 or more contains a residue of a primary hydroxyl group at the end because it is easier to accelerate the initiation reaction and shorten and suppress the induction period. is that the hydroxyl group residues of the urethane prepolymer (E) contain 0.1% or more of primary hydroxyl residues, more preferably 0.5% or more of primary hydroxyl group residues. . The upper limit of the ratio of primary hydroxyl groups in the hydroxyl group residues is not particularly limited, but it is preferably 92% or less, more preferably 92% or less, because raw materials are easily available and crystallinity tends to be low and handling properties are easy to be excellent. is less than 86%. Polyalkylene oxides containing a very small amount or more of primary hydroxyl groups at the terminals that form such residues are not particularly limited, but include, for example, polyalkylene oxides obtained using iminophosphazenium salt catalysts and Lewis acid catalysts, Examples include polyalkylene oxides obtained using boron-based Lewis acid catalysts, and the use of the above-mentioned polyalkylene oxides is preferred because the urethane prepolymer (E) can be easily obtained. Note that the ratio of the primary hydroxyl group residues may be determined by decomposing the urethane prepolymer and analyzing the polyol fraction.

Since the resulting cured urethane product tends to exhibit significantly better low-temperature properties and flexibility, the amount of residue derived from a low molecular weight polyol having a molecular weight of 600 or less is preferably in the range of 25% by weight or less; It is preferably 4% by weight or less, and most preferably not intentionally included. Among these, since the urethane cured product tends to exhibit significantly better flexibility, the amount of residue derived from a low molecular weight polyol with a molecular weight of 200 or less is preferably in the range of 10% by weight or less, and more preferably It is 1.5% by weight or less, and most preferably it is not intentionally included.

In addition, since the resulting cured urethane product tends to exhibit significantly better wettability and low-temperature properties, the aromatic structure such as aromatic amine residues and the number of carbon atoms in the urethane prepolymer (E) may be The content of 6 or more sugar residues, polyester residues, polyoxytetramethylene residues, and polycarbonate residues is preferably 20% by weight or less, more preferably 5% by weight or less, and most preferably intentionally It is not included in Although the alicyclic structure is not particularly limited, it is preferably in the range of 20% by weight or less, more preferably 5% by weight or less, and most preferably is intentionally not included.

In addition, the urethane prepolymer (E) may contain a polyol residue having three or more active hydrogen groups, which, although not particularly limited, tends to exhibit a low thixotropy index (TI value), and furthermore may cause gel-like substances or insoluble substances. The average number of functional groups of the raw material polyol used for prepolymer formation is less than 2.5 because it is difficult to form a urethane-forming composition (H) that is difficult to form, can be highly solidified, and has good coating properties regardless of conditions. It is preferable that the urethane is contained in a range such that it is more stable, has a high solid content, has an appropriate viscosity, has excellent coatability and productivity, and the resulting cured urethane product is flexible while maintaining cohesive force. The range is from 1.90 to 2.20, most preferably from 1.97 to 2.10, since it is easy to exhibit excellent followability. Note that the average number of functional groups of the raw material polyol in this embodiment is a value that takes into account the reduction in the actual number of functional groups due to unsaturated monool produced as a by-product during the production of polyalkylene oxide. In addition, the content weight of polyol residues having three or more active hydrogen groups in the urethane prepolymer (E) is 20 to The amount is preferably within the range of 0 to 10% by weight, and more preferably 0 to 10% by weight. Among these, the content of the initiator residue of the polyol 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 0 to 3% by weight. The amount is in the range of 0.3% by weight, and examples of such initiator residues include trimethylolpropane residues, glycerin residues, and pentaerythritol residues.
Although not particularly limited, the urethane prepolymer (E) may contain polyisocyanate residues because the resulting cured urethane has an excellent balance between wettability and cohesive force, and can easily achieve both significantly high ball tack and removability. It is preferable to contain the group in the range of 0.01 to 20% by weight, more preferably in the range of 0.1 to 10% by weight, and among them, it is easy to become more flexible and conformable while maintaining cohesive force. The most preferable range is 0.5 to 3% by weight because it tends to have a good content.

Furthermore, the polyisocyanate residue is not particularly limited, but examples of the polyisocyanate residue that can be used include aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, aromatic polyisocyanate residues, and modified products thereof. , aliphatic polyisocyanate residues, alicyclic polyisocyanate residues, or modified products thereof, because the coloring of the urethane prepolymer composition (G) is likely to be reduced and a cured urethane product with higher flexibility is likely to be obtained. It is preferable that the polyisocyanate residue is contained, and more preferably it is an aliphatic polyisocyanate residue or a modified product thereof, since it is easy to obtain a significantly flexible urethane cured product while maintaining high cohesive force. . In addition, the residues of the modified polyisocyanate include, but are not particularly limited to, urethane groups such as adduct types, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, and uretonimine groups. , residues of modified products containing uretdione groups or oxazolidone groups, and 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 and nurate/allophanate modification, can also be suitably used. Among these, when using a modified product, it is preferable to include one or more of urethane-modified and allophanate-modified structures because it tends to exhibit significantly good wettability.

As for the content of each residue in the urethane prepolymer (E), the composition ratio may be determined by decomposing each raw material by Collish decomposition, alkaline decomposition, etc., if necessary, and the composition ratio of each raw material can be determined. If so, 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 because it has a suitable viscosity, tends to have good moldability, and provides a good coating film appearance. Among them, it is preferable that the weight average molecular weight is in the range of 5,000 to 200,000, more preferably in the range of 8,000 to 50,000, and most preferably in the range of 15,000 to 40,000. It is.

The molecular weight distribution of the urethane prepolymer (E) is usually preferably less than 6.0, but it is more preferable that the thixotropy index of the urethane prepolymer composition (G) is more likely to decrease, and the handling property of the liquid is improved regardless of the viscosity. It is less than 1.50, more preferably less than 1.35, and most preferably in the range of 1.05 to less than 1.35, because it tends to have excellent flowability and excellent moldability. be. The urethane prepolymer (E) exhibiting a narrow molecular weight distribution that tends to significantly improve the fluidity of the liquid mentioned above is a polyalkylene oxide that is difunctional and has a low degree of unsaturation, particularly a polyalkylene oxide that is difunctional and has a degree of unsaturation of 0.004 meq/g. It is easy to obtain by using a polyalkylene oxide which has a significantly low molecular weight distribution of less than 1.039 and a significantly narrow molecular weight distribution of less than 1.039. Alkylene oxides are mentioned, and the use of the above-mentioned polyalkylene oxides is preferred because the urethane prepolymer (E) can be easily obtained.

The weight average molecular weight and molecular weight distribution of the urethane prepolymer (E) can be measured according to a conventional method using gel permeation chromatography (GPC) using polystyrene as a standard substance and tetrahydrofuran as an eluent. In addition, the urethane prepolymer composition (G) was measured using a gel permeation chromatography (GPC) method, and the weight average of the urethane prepolymer (E) was determined by removing peaks such as polyalkylene oxide (B). The molecular weight and molecular weight distribution may be calculated.

The method for producing the urethane prepolymer (E) is not particularly limited, but it can be produced by reacting raw materials containing polyol and polyisocyanate using various methods. For example, it can be produced by reacting at a temperature from room temperature to 150°C to proceed with the urethanization reaction. Further, the urethane prepolymer composition may be manufactured using known solvents, catalysts, various additives, etc., the urethane prepolymer composition may be prepared as it is, and the remaining components may be removed, or each component may be removed.

In addition, there is a method in which an active hydrogen compound such as a polyol and a polyisocyanate are polymerized with an excess of hydroxyl groups to directly form a urethane prepolymer with hydroxyl group terminals, and an active hydrogen compound such as a polyol and a polyisocyanate are polymerized with an excess of NCO groups to form a urethane prepolymer with an excess of NCO groups. A two-stage polymerization method may be used, in which after forming a urethane prepolymer with terminal ends, a polyol is additionally added and reacted to form a urethane prepolymer with hydroxyl groups in two steps, and any of these methods can be used.
Although not particularly limited, in the method of forming an NCO group-terminated urethane prepolymer, additionally adding polyol and reacting to form a hydroxyl group-terminated urethane prepolymer in two stages, when converting from NCO group end to hydroxyl group end, Low molecular weight polyols with a high hydroxyl value may be required, and the characteristics of significantly better flexibility and significantly lower glass transition temperature tend to be milder than those produced by one-stage polymerization. However, it can be adapted as long as the characteristics are not impaired.

Most preferably, an active hydrogen compound such as a polyol and a polyisocyanate are polymerized in one step with an excess of hydroxyl groups, and the hydroxyl groups are directly terminated, since it is easy to reduce the amount of urethane groups and exhibit significantly better flexibility and low-temperature properties. urethane prepolymer. Further, it is also possible to suitably add a small amount of an active hydrogen compound such as a polyol or a polyisocyanate in portions to carry out polymerization in two or more stages.
The polyol and polyisocyanate compound used in producing the urethane prepolymer (E) are preferably used after being dehydrated by vacuum heating, etc., but if the work becomes complicated, they may be used without dehydration. .
(Urethane prepolymer raw material)
The urethane prepolymer (E) is not particularly limited, but the urethane prepolymer (E) is preferably a reaction product of at least a polyalkylene oxide (A) and a polyisocyanate compound (C).

The polyalkylene oxide (A) preferably used for forming the urethane prepolymer (E) is not particularly limited, but it tends to have good removability, wettability, flexibility, and low-temperature properties. It is preferable to contain a polyalkylene oxide having two hydroxyl groups with a molecular weight of less than 0.010 meq/g and a molecular weight calculated from the hydroxyl value in the range of 3,000 to 10,000.

If the degree of unsaturation of the polyalkylene oxide (A) is 0.010 meq/g or less, the urethane prepolymer (E) obtained using it will be cured (solidified) due to the reaction with an isocyanate crosslinking agent, etc. It is preferable because it tends to be faster and the strength and cohesive force of the obtained cured urethane product are more easily improved, but it is more preferably 0.007 meq/g or less, and most preferably the low molecular weight components are significantly less and the characteristics are improved. It is 0.004 meq/g or less because stain resistance and removability are easily improved.

Here, the "degree of unsaturation (meq/g)" of polyalkylene oxide (A) is the amount of unsaturated groups contained per 1 g of polyalkylene oxide, and the amount of unsaturated monols contained in polyalkylene oxide. corresponds to a number. That is, the higher the degree of unsaturation, the more unsaturated monols there are, and the lower the degree of unsaturation, the less unsaturated monols.

In this embodiment, the degree of unsaturation of the polyalkylene oxide (A) was measured in accordance with the NMR method described in Kobunshi Ronsen 1993, 50, 2, 121-126. In this embodiment, since the polyalkylene oxide (A) with significantly less unsaturated monool is to be measured, the number of integrations in the NMR measurement was set to 500 or more in order to improve measurement accuracy.
The polyalkylene oxide (A) preferably used to form the urethane prepolymer (E) is not particularly limited, but as long as the number average molecular weight calculated from the hydroxyl value is in the range of 3,000 to 10,000, the resulting urethane prepolymer composition It is preferable because the product (G) has a constant viscosity and is easily divided into high solids, and the wettability, flexibility, and low-temperature properties of the cured urethane product are more likely to be improved. 7000 or less.

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

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, The most preferred range is 1.005 to 1.039. When Mw/Mn is within the above range, it is preferable because the amount of low-molecular-weight substances that cause contamination is reduced, which facilitates the development of better stain resistance. The molecular weight distribution (Mw/Mn) can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

The polyalkylene oxide (A) preferably used for forming the urethane prepolymer (E) preferably contains a bifunctional polyalkylene oxide having two hydroxyl groups. By including the bifunctional polyalkylene oxide (A), the resulting urethane prepolymer (E) has a linear high molecular weight, exhibits a low thixotropy index (TI value), and produces gel-like substances and insoluble matter. It is easy to obtain a urethane prepolymer composition (G) and a urethane-forming composition (H) that have good coating properties regardless of conditions.

Among these, the polyalkylene oxide (A) preferably used for forming the urethane prepolymer (E) preferably contains a primary hydroxyl group. Having even a very small amount of primary hydroxyl groups speeds up the initiation reaction during the formation of the urethane prepolymer, making it easier to shorten and suppress the initial induction period of the reaction, making it easier to suppress overshoot of heat generation, and stabilizing the quality. , it is easy to improve productivity and reduce the burden on the environment.

Among these, it is preferable to contain a primary hydroxyl group at the end of a polyalkylene oxide having a relatively low reactivity and a number average molecular weight of 3000 or more, since this makes it easier to accelerate the initiation reaction and shorten and suppress the induction period. The primary ratio of hydroxyl groups in A) is more preferably 0.1% or more, and even more preferably 0.5% or more.

Such polyalkylene oxides containing a very small amount or more of primary hydroxyl groups at the molecular terminals are not particularly limited, but include, for example, polyalkylene oxides obtained using an iminophosphazenium salt catalyst and a Lewis acid catalyst; The urethane prepolymer (E) can be easily obtained by using the polyalkylene oxide, which is preferable. The upper limit of the ratio of primary hydroxyl groups is not particularly limited, but it is preferably 92% or less, more preferably 86% or less, because it is easy to produce, easy to obtain, and has low crystallinity and is easy to handle. % or less. The primary ratio of hydroxyl groups in polyalkylene oxide may be measured by a known method such as adding a fluorine compound such as trifluoroacetic anhydride to the hydroxyl group and measuring NMR. may be analyzed.

The polyalkylene oxide (A) preferably used for forming the urethane prepolymer (E) preferably contains an alkylene oxide residue having 3 or more carbon atoms in one molecule. The alkylene oxide residue having 3 or more carbon atoms is not particularly limited, and examples thereof include alkylene oxide residues having 3 to 20 carbon atoms. Specifically, propylene oxide residue, 1,2-butylene oxide residue, 2,3-butylene oxide residue, isobutylene oxide residue, butadiene monoxide residue, pentene oxide residue, styrene oxide residue, cyclohexene Examples include oxide residues. Among these alkylene oxide residues, propylene oxide residues are preferred because raw materials for obtaining polyalkylene oxide (A) are easily available and the obtained polyalkylene oxide (A) has high industrial value.

Moreover, the polyalkylene oxide (A) may contain only a single alkylene oxide residue as the alkylene oxide residue having 3 or more carbon atoms, or may contain two or more types of alkylene oxide residues. good. In addition, when two or more types of alkylene oxide residues are included, for example, one type of alkylene oxide residue is connected in a chain, and other alkylene oxide residues are connected in a chain. Alternatively, two or more alkylene oxide residues may be randomly connected. Furthermore, the polyalkylene oxide (A) only needs to contain an alkylene oxide residue having 3 or more carbon atoms, and may also contain an ethylene oxide residue having 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 because it has low crystallinity and is difficult to solidify at low temperatures and tends to have excellent moldability. Yes, and most preferably not.

The isocyanate compound (C) preferably used for forming the urethane prepolymer (E) is not particularly limited, although it is preferable if the average number of functional groups in the isocyanate group is 2.0 or more. Examples of the isocyanate compound (C) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and tolizine. Diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tetramethylxylylene 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 Examples include isocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, modified isocyanate obtained by reacting these with polyalkylene oxide, and mixtures of two or more of these. Furthermore, modified products containing a urethane group, a carbodiimide group, an allophanate group, a urea group, a biuret group, an isocyanurate group, an amide group, an imide group, a uretonimine group, a uretdione group, or an oxazolidone group in these isocyanates, and polymethylene polyphenylene polyisocyanates. Examples include condensates such as (polymeric MDI).

Among these, aliphatic isocyanates, alicyclic isocyanates, or modified products thereof are preferred because they are easy to obtain a highly transparent urethane prepolymer composition (G) with little coloring. 1,6-hexamethylene diisocyanate, isophorone diisocyanate, aliphatic isocyanate-containing prepolymers, alicyclic isocyanate-containing prepolymers, or urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups of these isocyanates, Modified products containing an isocyanurate group, an amide group, an imide group, a uretonimine group, a uretdione group, or an oxazolidone group are more preferred. These isocyanates may be used alone or in combination of two or more.
The urethane prepolymer (E) may be made of an active hydrogen compound different from the polyalkylene oxide (A) or an isocyanate compound different from the polyisocyanate compound (C) depending on the required properties and viscosity, and is not particularly limited. .

For example, in addition to polyalkylene oxide (A) and polyisocyanate compound (C), other polyols such as trifunctional or higher functional polyalkylene oxide or bifunctional polyalkylene oxide with a molecular weight of less than 3,000 are added to increase the cohesive force. Although it is possible to react in combination to form urethane prepolymer (E), it tends to show a low thixotropy index (TI value), and it is difficult to generate gel-like substances and insoluble matters, so it is good regardless of the conditions. Since it is easy to obtain a urethane-forming composition (H) with good coating properties, it is preferable that the average functional group number fave of all polyols used for forming the urethane prepolymer (E) is less than 2.5; It is preferably in the range of 1.85 to 2.20, most preferably in the range of 1.95 to 2.10. Note that the average number of functional groups of the raw material polyol in this embodiment is a value that does not take into account the reduction in the actual number of functional groups due to unsaturated monool produced as a by-product during polyalkylene oxide production. In addition, since good flexibility and low-temperature properties of the obtained cured urethane product can be easily maintained, when used, the amount is preferably 30% by weight or less in the urethane prepolymer (E), and more preferably 10% by weight or less. % by weight or less, most preferably in the range of 0.01 to 4% by weight.
For reasons such as increasing cohesion, relatively rigid structures such as polyoxytetramethylene glycol, polyester polyols, aromatic amine-initiated polyols, aliphatic amine polyols, sugar residue-initiated polyols with 6 or more carbon atoms, and polycarbonate polyols are used. However, since it is easy to maintain good flexibility and low-temperature properties of the resulting cured urethane product, the amount is preferably 20% by weight or less, more preferably 5% by weight or less. most preferably in the range of 0.001 to 1% by weight.

Monofunctional polyols such as polyoxyethylene glycol alkyl ether may be used for reasons such as improving coatability, but since the cohesive force tends to decrease, when used, 5% by weight of the urethane prepolymer (E) % or less, more preferably 2% by weight or less, and most preferably 0.001 to 0.5% by weight.

In addition, in addition to polyalkylene oxide (A) and isocyanate compound (C), other polyisocyanates such as trifunctional or higher functional isocyanate compounds and monofunctional isocyanate compounds may be used in combination for reasons such as increasing cohesive force and moldability. Although the urethane prepolymer (E) may be formed by reaction, it tends to show a low thixotropy index (TI value), is less likely to generate gel-like substances or insoluble matter, and has good coating properties regardless of the conditions. In order to easily obtain the urethane-forming composition (H), it is preferable that the average number of functional groups fave of all the polyisocyanates used for forming the urethane prepolymer (E) is less than 2.8, especially 1 contained in impurities etc. 1.90 to 2.0 because the amount of terminal-blocking components such as functional isocyanate is reduced, and the prepolymer is chain-extended to easily increase cohesive force, and the high solids content provides a constant viscosity and improves moldability. It is preferably in the range of 79, more preferably in the range of 1.98 to 2.49, and most preferably in the range of 2.0 to 2.09.
<Polyalkylene oxide (B)>
The urethane prepolymer composition (G) of the present invention contains polyalkylene oxide (B) as an essential component. Further, the polyalkylene oxide (B) contains a polyalkylene oxide (B1) having three or more hydroxyl groups as an essential component.

If polyalkylene oxide (B) is not included in the urethane prepolymer composition, the amount of urethane groups may be reduced and the cohesive force may be insufficient, resulting in adhesive residue, or the adhesion may become too high and damage the adherend. This makes stable re-peeling difficult and difficult to use. In addition, if the polyalkylene oxide (B) does not contain the polyalkylene oxide (B1) having three or more hydroxyl groups, the cohesive force may be insufficient and adhesive residue may occur, or the adhesive force may be too high and the adherend may This makes it difficult to achieve stable removability, making it difficult to use.

The upper limit of the number of hydroxyl groups in polyalkylene oxide (B) is not particularly limited as long as it contains polyalkylene oxide (B1) having three or more hydroxyl groups in one molecule, but the number of hydroxyl groups in one molecule is 6 or less. The number of hydroxyl groups in one molecule is preferably 4 or less, and the average number of hydroxyl groups in one molecule is most preferably in the range of 2.1 to 3. If the number of hydroxyl groups in one molecule of polyalkylene oxide (B) is 6 or less, even if the molecular weight of polyalkylene oxide (B) is low, the urethane prepolymer (E) obtained using it, This is preferable because the crosslinked structure of polyurethane obtained by reaction with an isocyanate crosslinking agent or the like is less likely to become dense and tends to exhibit better wettability and appropriate adhesiveness.

Here, the polyalkylene oxide (B1) having three or more hydroxyl groups in one molecule is prepared by, for example, opening the alkylene oxide with a compound containing three or more active hydrogens as an initiator in the presence of an alkylene oxide polymerization catalyst. Obtained by ring polymerization. Therefore, the polyalkylene oxide (B) will have alkylene oxide residues.

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. . If the degree of unsaturation of the polyalkylene oxide (B) is 0.070 meq/g or less, the urethane prepolymer (E) obtained using it will be cured (solidified) quickly due to the reaction with the isocyanate crosslinking agent, etc. This is preferable because the resulting polyurethane tends to have high strength and cohesive force.

Here, the "degree of unsaturation (meq/g)" of polyalkylene oxide (B) is the amount of unsaturated groups contained per 1 g of polyalkylene oxide, and the amount of unsaturated monools contained in polyalkylene oxide. corresponds to a number. That is, the higher the degree of unsaturation, the more unsaturated monols there are, and the lower the degree of unsaturation, the less unsaturated monols. In this embodiment, the measurement was performed according to the method of JIS-K1557-6.

Polyalkylene oxide (B) is not particularly limited as long as it contains polyalkylene oxide (B1) having three or more hydroxyl groups in one molecule, but it exhibits better wettability in addition to good curability. For ease of use, the average number of functional groups of the polyalkylene oxide (B1) is preferably in the range of 2.40 to 4.99, more preferably in the range of 2.55 to 3.99.

In addition, if the polyol in the urethane prepolymer (E) contains a large amount of unsaturated monool, it will be easy to end-block when forming the urethane prepolymer, resulting in long dangling chains and deteriorating the physical properties. Although it is desirable to have less monool, polyalkylene oxide (B) contains polyalkylene oxide (B1) having three or more hydroxyl groups in one molecule, and even if the average number of functional groups is lowered by unsaturated monool, the ball The average number of functional groups of the polyalkylene oxide (B1) is within the range of 2.65 to 2.98 because it is easy to improve the wettability with tack etc., and it is easy to exhibit better wettability in addition to good curability. Most preferably. Examples of such polyalkylene oxides include polyalkylene oxides obtained using cesium hydroxide catalysts, iminophosphazenium catalysts, phosphazene catalysts, double metal cyanide complex catalysts (DMC catalysts), etc. It is preferable to use polyalkylene oxide (B) having the above-mentioned average number of functional groups because it is easy to obtain the polyalkylene oxide (B), but when the number average molecular weight is as low as 1900 or less, a general-purpose catalyst such as potassium hydroxide can also be used.

Polyalkylene oxide (B) is not particularly limited, but it is easy to achieve both moldability and curability during the reaction between urethane prepolymer (E) and isocyanate crosslinking agent, etc., and the resulting polyurethane has high strength and cohesive force. Since it tends to become large, the number average molecular weight calculated from the hydroxyl value is preferably 700 or more and 30,000 or less, more preferably 800 or more and 12,000 or less.

Among them, it has a large number of trifunctional or higher functional groups and hydroxyl groups, and also tends to show higher reactivity and is less likely to remain in the resulting cured urethane product, so the number average molecular weight calculated from the hydroxyl value is 900 or more and 4500 or less. It is preferably 1000 or more and 1900 or less.

On the other hand, although the reactivity tends to decrease, the resulting cured urethane product tends to exhibit more remarkable flexibility and wettability, so in applications that require such characteristics, the number average molecular weight calculated from the hydroxyl value is 4500. It is preferably from 6,500 to 10,000, more preferably from 6,500 to 10,000. Moreover, it is preferable that the polyalkylene oxide (B1) in the polyalkylene oxide (B) also has a number average molecular weight within the above range for the same reason.

The number average molecular weight of the polyalkylene oxide (B) is determined by the hydroxyl value of the polyalkylene oxide (B) calculated by the method described in JIS K-1557-1 and the number of hydroxyl groups in one molecule of the polyalkylene oxide (B). It can be calculated from. Further, the number average molecular weight was calculated without taking into account the actual decrease in the average number of hydroxyl groups derived from unsaturated monools.
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, more preferably 1.06 or less. When Mw/Mn is within the above range, it is preferable because the amount of low molecular weight substances that cause contamination is reduced, so that better stain resistance is easily exhibited. Moreover, it is preferable that the polyalkylene oxide (B1) in the polyalkylene oxide (B) also has a molecular weight distribution within the above range for the same reason.

The molecular weight distribution (Mw/Mn) can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

It is preferable that the polyalkylene oxide (B) contains an alkylene oxide residue having 3 or more carbon atoms in one molecule. The alkylene oxide residue having 3 or more carbon atoms is not particularly limited, and examples thereof include alkylene oxide residues having 3 to 20 carbon atoms. Specifically, propylene oxide residue, 1,2-butylene oxide residue, 2,3-butylene oxide residue, isobutylene oxide residue, butadiene monoxide residue, pentene oxide residue, styrene oxide residue, cyclohexene Examples include oxide residues. Among these alkylene oxide residues, propylene oxide residues are preferred because raw materials for obtaining polyalkylene oxide (B) are easily available and the obtained polyalkylene oxide (B) has high industrial value.

Further, the polyalkylene oxide (B) may contain only a single alkylene oxide residue as the alkylene oxide residue having 3 or more carbon atoms, or may contain two or more types of alkylene oxide residues. good. In addition, when two or more types of alkylene oxide residues are included, for example, one type of alkylene oxide residue is connected in a chain, and other alkylene oxide residues are connected in a chain. Alternatively, two or more alkylene oxide residues may be randomly connected. Furthermore, the polyalkylene oxide (B) only needs to contain an alkylene oxide residue having 3 or more carbon atoms, and may also contain an ethylene oxide residue having 2 carbon atoms. The content of ethylene oxide residues in the polyalkylene oxide (B) is preferably 50% by weight or less, more preferably 30% by weight or less since it is difficult to solidify at low temperatures and tends to have excellent moldability.

There are no particular limitations 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 in the presence of a ring-opening polymerization catalyst using a trifunctional or higher-functional polyvalent initiator.

Examples of trifunctional or higher-functional polyvalent initiators include, but are not limited to, glycerin, trimethylolpropane, 1,2,6-hexanetriol, Sanyo Chemical Co., Ltd. Sunnix GP-250, GP-400, and GP-600. , triols such as trifunctional low molecular weight polyols with a molecular weight of 1000 or less such as GP-1000, tetraols such as pentaerythritol and diglycerin, and amines such as hexol, ammonia, ethanolamine, diethanolamine, and triethanolamine. One or more kinds of compounds having the above active hydrogen can be used. Among these, it is preferable to contain residues of triols such as glycerin, trimethylolpropane, 1,2,6-hexanetriol, and trifunctional low molecular weight polyols having a molecular weight of 1000 or less.
<Additives>
The urethane prepolymer composition (G) contains as additives a ketoenol tautomer compound, an acid retarder, other retarders, a urethanization catalyst, an antistatic agent, a plasticizer, an antioxidant, a leveling agent, a solvent, and a chain extender. , fillers, stabilizers, and other additives.

Among these, the urethane prepolymer composition (G) of the present invention preferably contains a urethanization catalyst containing a metal component and a ketoenol tautomer compound, more preferably a urethanization catalyst containing a metal component and a ketoenol tautomer compound. It is preferable to contain a compound together.

By including a urethanization catalyst containing a metal component, the reactivity during prepolymer formation is improved compared to using only a urethanization catalyst that does not contain a metal component such as an amine catalyst, or a non-catalytic system. In addition, when forming a cured urethane product using an isocyanate crosslinking agent, etc., the reaction between the moisture in the air and the isocyanate crosslinking agent takes precedence over the reaction between the urethane prepolymer (E) and polyalkylene oxide (B). Since the reaction of the isocyanate crosslinking agent progresses, the curability tends to be significantly improved.

The content of the urethane catalyst containing a metal component in the urethane prepolymer composition (G) is not particularly limited. The amount is preferably in the range of 0.001 to 0.5 parts by weight per 100 parts by weight of prepolymer (E). Among these, it is more preferable that the content of the urethanization catalyst containing a metal component is in the range of 0.001 to 0.1 parts by weight, most preferably in order to achieve both curability and a significantly long pot life. The range is from 0.005 to 0.07 parts by weight.

The urethanization catalyst containing a metal component is not particularly limited as long as it is a compound that contains a metal component and exhibits urethanization activity, but since it is easy to adjust the catalyst activity and extend the molding time with various additives, Fe, Zr, etc. , Ti, and Al. Among them, one or two types of metal chelate catalysts such as Fe chelate catalyst, Zr chelate catalyst, Ti chelate catalyst, and Al chelate catalyst are used because they are easy to extend pot life, have good curability, and have good moldability. The above is preferred, and more preferred is an Fe chelate catalyst that tends to exhibit a significantly long pot life.

Although not particularly limited, examples of Fe chelate catalysts include iron trisacetylacetonate, Zr chelate catalysts include zirconium tetraacetylacetonate and zirconium ethylacetoacetate, and Ti chelate catalysts include titanium acetylacetonate and titanium ethylacetonate. Examples of Al chelate catalysts such as acetate include aluminum trisacetylacetonate.

The urethane prepolymer composition (G) reduces the catalytic activity of the urethanization catalyst containing metal components in the liquid and synergistically extends the pot life. The urethane prepolymer composition (G) preferably contains one or more ketoenol tautomer compounds, most preferably contains acetylacetone because it can be removed in a drying step and the catalyst activity can be easily reactivated. The content thereof is preferably in the range of 0.001 to 20 parts by weight, more preferably in the range of 0.005 to 10 parts by weight.

Among them, although not particularly limited, the urethane prepolymer composition (G) of the present invention has a urethane prepolymer (E) having a low molecular weight and a polyalkylene oxide (B) containing a polyfunctional component not in the molecule but as a mixture. The urethane prepolymer composition ( The content of the ketoenol tautomer compound in G) is more preferably in the range of 0.01 to 1.0% by weight, still more preferably in the range of 0.01 to 0.7% by weight, and most preferably ranges from 0.01 to 0.3% by weight. In addition, if a ketoenol tautomer compound is included, the molar ratio (ketoenol tautomer compound/metal catalyst) to the urethanization catalyst containing a metal component is 3 to 1000 times, since the pot life tends to be longer. The range is preferably 5 times to 100 times, more preferably 5 times to 100 times.

Among these, 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 the isocyanate crosslinking agent C2770 is added to the urethane prepolymer composition (G). ) It is preferable that the time required for a 20% increase in viscosity when mixed so that the amount of NCO groups is 1.3 equivalents to the total amount of hydroxyl groups in Cheap. More preferably, the content of the ketoenol tautomer compound is in the range of 0.01 to 0.7% by weight, and the isocyanate crosslinking agent C2770 is added to the total amount of hydroxyl groups in the urethane prepolymer composition (G). It is preferable that the time required for a 20% increase in viscosity when mixed to have an NCO group amount of 1.3 equivalents is 24 hours or more, and most preferably, the content of the ketoenol tautomer compound is 0.01 ~0.3% by weight, and when the isocyanate crosslinking agent C2770 is mixed so that the amount of NCO groups is 1.3 equivalents based on the total amount of hydroxyl groups in the urethane prepolymer composition (G). It is preferable that the time required to increase the viscosity by 20% is 48 hours or more, and such properties can be easily obtained.

The acid retarder is not particularly limited, but preferably contains an acid with a pKa of 5.0 or less. Examples of such acids with a pKa of 5.0 or less include phosphoric acid retarders such as hydrochloric acid, nitric acid, phosphoric acid, and acidic phosphoric acid esters having 2 to 20 carbon atoms such as ethyl acid phosphate and 2-ethylhexyl acid phosphate. Among these, it is preferable to use a phosphorus acid retarder because it tends to provide a good balance between reactivity and physical properties.

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

Examples of plasticizers include, but are not limited to, fatty acid esters, alicyclic esters, polyether esters, etc., such as epoxidized fatty acid esters, myristate esters, terminal ester-modified compounds of polyalkylene glycol, etc. Can be mentioned.

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

The isocyanate compound (F) is not particularly limited, but the same compounds as the above-mentioned isocyanate compound (C) can be mentioned, and the same preferred isocyanates can also be mentioned. The isocyanate compound (F) and the isocyanate compound (C) may be the same or different.

Among these, isocyanate compounds are preferred because their compatibility improves, resulting in a more transparent urethane-forming composition (H), which makes it easier to obtain a highly transparent cured urethane product that is significantly more flexible and has excellent wettability. It is preferable that (F) contains an allophanate structure.

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

[R1 in the chemical formula (1) is a monool residue or a polyol residue. ]
In addition, when R1 in the chemical formula (1) is a polyol residue, it is not particularly limited, but for example, a structure shown in the following chemical formula (2) can be mentioned and preferably included.

[R1 in the chemical formula (2) is a polyol residue, and usually has a structure obtained by removing an n-valent hydroxyl group from a polyol, and n is usually in the range of 2 to 100. ]
R1 in the chemical formula (2) is preferably a monool residue or a polyol residue having 1 to 50 carbon atoms because it tends to have better compatibility.

In the chemical formula (2), n is preferably an integer in the range of 1 to 2 (R1 is a monol residue or a diol residue) because it increases the mobility and tends to have better wettability.

In addition, since the isocyanate compound (F) has high versatility and tends to exhibit good physical properties, aromatic isocyanate residues, aliphatic isocyanate residues, alicyclic isocyanate residues, or modified products of these isocyanates are used. It is more preferable to use one or more of the following: aliphatic isocyanate residues, alicyclic isocyanate residues, or residues of modified products of these isocyanates because they tend to have excellent transparency. It is any one or more of them, and most preferably it is any one or more of the residues of 1,6-hexamethylene diisocyanate, isophorone diisocyanate, and allophanate-modified and/or isocyanurate-modified products of these isocyanates.

Among them, allophanate modified products of 1,6-hexamethylene diisocyanate are used because they have high reactivity, good productivity of cured urethane products, and the resulting cured urethane products are more easily flexible and have excellent wettability. It is preferable to include.

The average number of isocyanate functional groups calculated by the gel permeation chromatography (GPC) method of polyisocyanate (F) is 1.90 to 2.0, because it is easier to develop flexibility and wettability while maintaining cohesive force. It is preferably in the range of 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. range.
The average number of isocyanate functional groups of polyisocyanate (F) is calculated by the following formula using the number average molecular weight and isocyanate content (isocyanate group concentration) of polyisocyanate calculated by gel permeation chromatography (GPC). did.
Number of isocyanate functional groups = (polyisocyanate number average molecular weight x isocyanate group concentration) / (42 x 100)
In addition, 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; It is preferable that the ratio (M _NCO /M _OH ) of the amount (M _NCO ) is 0.5 or more and less than 4.0 in terms of molar ratio, and more preferably, the curability is better and the resulting urethane cured product has a The range is 0.9 or more and less than 2.5, and most preferably 1.0 or more and less than 1.7 because carbon dioxide gas bubbles are less likely to occur due to the reaction between excess NCO groups and moisture in the air. .

Further, the weight ratio of the urethane prepolymer composition (G) and the isocyanate compound (F) in the urethane-forming composition (H) (weight of (G)/weight of (F)) is not particularly limited, but is usually 99. The range is from /1 to 20/80, preferably from 98/2 to 50/50.
Among these, the urethane prepolymer composition (G) of the present invention is easy to form a cured urethane product that exhibits removability with good cohesive force without mixing a large amount of low molecular weight polyol with a high hydroxyl value. isocyanate compound (F), and the weight ratio of the urethane prepolymer composition (G) to the isocyanate compound (F) (weight of (G)/weight of (F)) is 97/3. The range is preferably 85/15 to 85/15, and most preferably 96/4 to 90/10. By containing it in the above ratio, it is easy to obtain a cured urethane product that is significantly more flexible while maintaining cohesive force. In addition, since it is possible to cure with a small amount of isocyanate compound (F) without mixing a large amount of low molecular weight polyol with a high hydroxyl value, the viscosity increase after mixing the crosslinking agent is gradual, resulting in a long pot life. This makes it easier to improve handling.

The urethane-forming composition (H) may contain the additives and the like exemplified in the urethane prepolymer composition (G), and may be added as necessary. The preferable types and content ranges of the additives are also the same as the preferable types and content ranges of the urethane prepolymer composition (G). When the type and content of the additive is within this range, good coating properties can be obtained when applying the urethane-forming composition (H) with a coating machine, and good pot life and curability can be obtained. The urethane cured product obtained also tends to exhibit more remarkable flexibility.

The preparation of the urethane-forming composition (H) is not particularly limited as long as the prepolymer and raw materials can be uniformly dispersed, and various conventionally known stirring methods may be used. can be mentioned. Examples of the stirrer include a general-purpose stirrer, a rotation-revolution mixer, a disperser disperser, a dissolver, a kneader, a mixer, a laboplast mill, a planetary mixer, and the like. When the urethane-forming composition (H) is liquid at the stirring temperature, a general-purpose stirrer, a rotation-revolution mixer, a disperser disperser, or a dissolver is suitably used.

The viscosity of the urethane-forming composition (H) at 25°C is not particularly limited, but it should be in the range of 0.1 to 30 Pa·s because it is less likely to flow and can be uniformly formed into thin to thick films. is preferably in the range of 1 to 20 Pa·s, and most preferably in the range of 3 to 15 Pa·s. In addition, although not particularly limited, even under high temperature conditions such as during the drying process, molding defects such as liquid flow, generation of voids, and increased thickness at the coating end are less likely to occur, so the viscosity at 80°C is 0.05 to 20 Pa・s. It is preferably in the range of , 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. Further, it is preferable that it is a uniform liquid at 0 to 25°C and that there is no separation upon standing.

In addition, when an organic solvent is used in the urethane-forming composition (H), the organic solvent is not particularly limited, and examples thereof include the organic solvents exemplified as organic solvents that may be included in the urethane prepolymer composition (G). . The preferred concentration range and solution viscosity are also the same as the preferred concentration range and solution viscosity of the urethane prepolymer composition (G). When the concentration range and solution viscosity are within this range, good coating properties can be obtained when the urethane-forming composition (H) is applied with a coating machine, etc., making it easy to handle. .

The urethane-forming composition (H) has a low molecular weight of less than 100,000 urethane prepolymer (E), and mainly contains polyalkylene oxide (B), which is a polyfunctional component, not in the molecule but as a mixture. The viscosity increases slowly after mixing with the isocyanate compound (F), has a long pot life and is easy to handle, has a non-volatile content concentration of 80% by weight or more, and takes 4 hours to increase the viscosity by 20%. It is preferable that it is above, and it is easy to obtain such a property.

Among them, the urethane-forming composition (H) has a nonvolatile content concentration of 80% by weight or more, a ketoenol tautomer compound content in the range of 0.01 to 1.0% by weight, and a viscosity of 20%. It is preferable that the time required for the rise is 15 hours or more, and such properties are likely to be obtained.
More preferably, the concentration of nonvolatile matter is 90% by weight or more, the content of the ketoenol tautomer compound is in the range of 0.01 to 0.7% by weight, and the time required to increase the viscosity by 20% is 24 hours or more. Most preferably, the concentration of nonvolatile matter is 95% by weight or more, 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 It is preferable that the period of time is 48 hours or more, and it is easy to obtain such properties.

<Urethane cured product (I)>
The urethane cured product (I) is a reaction product of the urethane-forming composition (H), and is a reaction product of the urethane-forming composition (H), which contains active hydrogen such as the urethane prepolymer (E) and polyalkylene oxide (B). Contains a reaction product of a compound and an isocyanate compound (F).

The cured urethane product (I) can be obtained by reacting the urethane-forming composition (H) by various methods and curing (solidifying) it. The method for producing the cured urethane (I) is not particularly limited. For example, the urethane-forming composition (H) is heated at room temperature or at a high temperature of 150° C. or lower in the presence of a urethanization catalyst, antioxidant, stabilizer, filler, crosslinking agent, other additives, etc. as necessary. It can be produced by proceeding with a urethanization reaction or a ureation reaction.

Further, in order to exhibit good curability, it may include a step of activating at a high temperature and a step of removing the solvent, if necessary.
The use of the cured urethane product (I) is not particularly limited, and it can be used in any application where ordinary polyurethane is used, but it is particularly suitable for applications that require mechanical properties, adhesive properties, etc. Can be used for Specifically, our products include sealants for construction and civil engineering, adhesives such as elastic adhesives for construction, gummed tape and surface protection films, various adhesives for optical applications, release materials, vibration damping materials, paints, elastomers, and coatings. Applications include membrane waterproofing materials, flooring materials, plasticizers, flexible polyurethane foams, semi-rigid polyurethane foams, rigid polyurethane foams, etc., and can be suitably used.

Among these, there are strong demands on polyurethane for adhesive properties, stain resistance, low VOC, cold resistance, flexibility, etc., and environmental adaptability, workability, coatability, and conformability to the substrate are required. Therefore, it is particularly preferable to use it as a sealant, paint, pressure-sensitive adhesive, or adhesive.

<Urethane sheet>
Since the urethane-forming composition (H) has significantly excellent coating properties when applied with a coating machine, it is possible to obtain a sheet of the cured urethane product (I) with a uniform thickness from a thin film to a high thickness. .

The thickness of the urethane sheet is not particularly limited, but the thickness of the coating film is preferably in the range of 0.1 to 3000 μm, and preferably in the range of 5 to 1000 μm, since the appearance of the coating film is particularly good. More preferably. In particular, since the urethane-forming composition (H) tends to have a high solid content and an appropriate viscosity, it is easy to obtain a sheet of the urethane cured product (I) with a uniform thickness up to a high thickness, and it should be in the range of 45 to 300 μm. is preferred.

Further, in order to facilitate application to various uses, a urethane sheet may have a structure of two or more layers including at least one base material and a layer of cured urethane (I) provided on the base material; In addition to the seed base material and the urethane cured product (I) layer provided on the base material, there are three or more layers including a release film layer, etc., or the urethane cured product (I) layer is provided on both sides of the base material. The urethane sheet may have a three-layer structure, or a five or more layer structure including a release film layer in addition to the urethane cured product (I) layer. Alternatively, a core material may be included in the adhesive layer to form a sheet.

<Urethane adhesive>
The cured urethane product (I) has excellent removability and exhibits significantly good flexibility and low-temperature properties, so it can be particularly suitably used as a urethane pressure-sensitive adhesive by including the cured urethane product (I). Also, it is preferable because it is derived from a raw material with a high solid content and is easy to form, resulting in a low-VOC product with a small impact on the environment.

The urethane adhesive of the present invention uses polyalkylene oxide with a low degree of unsaturation, easily retains crosslinking points even when the molecular weight is increased, and exhibits good flexibility and adhesive properties, and impact resistance from low to high temperatures. It's easy to do. Further, since the adhesive-forming composition has a suitable viscosity and is easily obtained with a uniform composition, it tends to have excellent transparency.

The urethane adhesive of the present invention preferably has an elastic modulus ^of 2×10 ⁴ Pa to 3×10 5 Pa or less, more preferably 3×10 ⁴ Pa to 2×10 ⁵ Pa, at a frequency of 1 Hz and 25° C. It is most preferably in the range of 5×10 ⁴ Pa to 1.5×10 ⁵ Pa. If the modulus of elasticity at a frequency of 1 Hz and 25°C is within the range of 2 x 10 ⁴ Pa to 3 x 10 ⁵ Pa, the adhesive will easily deform while maintaining cohesive force, so the adhesive such as holding power and adhesive force will be affected. This is preferable because it can easily suppress the generation of bubbles by following the steps of the adherend while exhibiting its characteristics.

In the present invention, the elastic modulus at 25°C is measured using a dynamic viscoelasticity measuring device Rheogel E-4000 manufactured by UBM, at a measurement temperature of -100°C to 200°C, a heating rate of 2°C/min, a frequency of 1Hz, and a shear mode. It means the value of storage elastic modulus G' at each temperature, measured under the following conditions.

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, the temperature is in the range of -80°C to -50°C. A glass transition temperature in the range of −30° C. or below is preferable because there will be no adhesive residue or a decrease in heat resistance, and peeling and cracking can be suppressed when dropped even at low temperatures, and high adhesion at low temperatures can be expected.

In the present invention, the glass transition temperature is measured using a dynamic viscoelasticity measurement device, Rheogel E-4000 manufactured by UBM, under measurement temperature of -100°C to 200°C, heating rate of 2°C/min, frequency of 1Hz, and shear mode conditions. The temperature at which the peak value of tan δ, which is the ratio of the loss modulus G" to the storage modulus G', was taken was evaluated as the glass transition temperature.

The adhesive strength of the urethane adhesive to alkali-free glass measured by the method of JIS Z0237 is not particularly limited, but it is preferably in the range of 0.1 N/25 mm to less than 30 N/25 mm, and more preferably a moderate adhesive strength. The removability is likely to be significantly excellent while exhibiting the following properties, so the range is from 0.5 N/25 mm to less than 10 N/25 mm. Further, although not particularly limited, from the viewpoint of removability, it is preferable that the form of peeling is interfacial peeling.

The adhesive strength of the urethane adhesive is a value measured according to JIS Z0237 using Eagle XG manufactured by Corning Inc. with a thickness of 0.7 mm as alkali-free glass. Specifically, the adhesive surface was lined with a PET film Lumirror S-10 manufactured by Toray Industries, Inc. with a thickness of 25 μm, cut into a width of 25 mm, and rolled crimped according to JIS Z0237 to prepare a test piece. 180° peeling was performed using a tensile tester RTG-1210 manufactured by Orientech Co., Ltd. in accordance with JIS Z0237 in an atmosphere of 23°C and 50% RH, a peeling angle of 180°, and a tensile speed of 300 mm/min. The adhesive force (N/25 mm) was defined as the adhesive force.

The ball tack of the urethane adhesive measured by the JIS Z0237 method is not particularly limited, but is preferably 6 or more. Among these, the range is preferably 21 or more, more preferably 25 or more, and most preferably 32 or more because it is easy to adhere instantaneously and follow steps. If the ball tack is 21 or more, the wettability is markedly excellent, and therefore the bonding time can be expected to be shortened, and furthermore, positional deviation etc. are suppressed, so productivity is likely to be improved.

The ball tack of the urethane adhesive of the present invention is a value evaluated according to JIS Z0237. Specifically, the ball tack of the urethane adhesive of the present invention is a value evaluated according to JIS Z0237. No. It is.

The holding power of the urethane adhesive used in the present invention measured by the method of JIS Z0237 is not particularly limited, but it is preferably 100 minutes or more at 40°C, more preferably 24 hours or more, and most preferably 24 hours or more. time or more, the deviation is less than 1 mm, and there is substantially no creep.

The holding power of the urethane adhesive is a value evaluated according to JIS Z0237. Specifically, it is pasted on a SUS base material with an adhesive surface of 25 mm x 25 mm, and maintained at 40°C and a static load of 1 kg until a weight is dropped. The time was evaluated. If the holding power is 100 minutes or more at 40° C., removability can be expected due to less migration components and high cohesive strength.

The haze of the urethane adhesive measured by the method of JIS K7136 is not particularly limited, but preferably the haze at a thickness of 80 μm is less than 2%, more preferably the haze is less than 0.4%, and most preferably the haze is less than 0.4%. Less than 0.2%. It is preferable that the haze at a thickness of 80 μm is less than 1% because transparency is high, visibility is excellent, and a good appearance can be expected. Although not particularly limited, when used for optical applications such as optical pressure-sensitive adhesive sheets, it is preferable that the haze at a thickness of 80 μm is less than 1%. Such an adhesive with a Haze of less than 1% at a thickness of 80 μm has a molar ratio of the total amount of NCO groups and the total amount of active hydrogen groups constituting the adhesive-forming composition ([total amount of NCO groups]/[total amount of OH groups]). It is preferable to manufacture under conditions such that 0.9 to less than 1.3.

In the present invention, Haze is a value excluding the base material used for measurement. Specifically, when the Haze of the PMMA base material is 0.2% and the Haze of the two-layer structure of PMMA and adhesive is 0.5%, the Haze of the adhesive is 0.5-0.2=0. It was set at 3%.

The urethane adhesive maintains moisture and heat resistance, does not easily whiten after being removed, and has good moisture and heat whitening resistance. Specifically, after being held for 5 days at 85° C. and 85% RH, it is taken out and left in a constant temperature room at 25° C. and 50% RH, after which 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, and have excellent vibration absorption, adhesion, low-temperature properties, and tackiness. Adhesion can be expected.

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

<Urethane adhesive sheet>
The urethane adhesive sheet of the present invention has at least one base material and an adhesive layer provided on the base material, and the adhesive layer contains the cured urethane product (I) of the present invention. shall be.

Examples of the base material used in the urethane adhesive sheet of the present invention include a release film, a core material, and the like. Examples of such a release film include PET, PP, TPX, silicone thereof, films subjected to release treatment such as fluorine, and the like. Commercially available products include, for example, releasable PET such as Purex A31, A33, A35, and A43 manufactured by Toyobo. Examples of the core material include nonwoven fabric, PET film, and PP film.

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

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. be. In particular, in the case of an optical adhesive sheet for film sensors, the range is preferably from 15 μm to 150 μm, and in the case of the optical adhesive sheet for glass sensors for use between a touch panel and a cover panel, the range is preferably from 50 μm to 300 μm.

The shape of the urethane adhesive sheet using the urethane adhesive may be any desired shape. Although not particularly limited, it may be in the form of a roll or may be cut into a sheet.

The method for producing the urethane adhesive sheet is not particularly limited, but for example, 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 obtain urethane-forming properties. After forming the composition, the composition may be coated using, for example, a roll coater, a gravure coater, a microgravure coater, a reverse coater, an air knife coater, a comma coater, a die coater, or the like. When using these coating methods, it is desirable to apply the urethane-forming composition to one or both sides of the substrate, and then defoam, heat, and dry as necessary.

As the heating method, commonly used methods such as hot air drying, hot roll drying, infrared irradiation, etc. 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 still more preferably 80 to 150°C. When using a thermoplastic resin as a base material, the drying temperature is desirably below its melting point. A drying temperature in the range of 50 to 200°C is preferable because deterioration of the base material and change in color tone are less likely to occur.

The uses of urethane adhesives and urethane adhesive sheets are not particularly limited, and include, for example, tapes, labels, stickers, decorative sheets, anti-slip sheets, double-sided adhesive tapes, and the like. Specifically, packaging tapes, label tapes, masking tapes, craft tapes, and other adhesive tapes for packaging, office work, and household use, medical tapes such as bandages, biological tapes for skin application, wallpaper tapes, and foam tapes. , construction tapes such as elastic adhesives for construction, tapes for electronic materials used in computers, televisions, mobile phones, automobiles, solar cells, and other home appliances, optical adhesive sheets used for adhesion of liquid crystal displays, touch panels, etc., manufacturing process. Surface protection tapes, waterproof tapes, conductive tapes, heat dissipating tapes, etc. are exemplified and can be suitably used.

The urethane adhesive and adhesive sheet of the present invention are particularly suitable for applications that require flexibility, such as adhesion to fragile substrates such as glass and prevention of shatter, adhesion to electronic equipment and other devices that are susceptible to vibrations and shocks, and foldable materials. It can be suitably used in applications where it is necessary to follow bending, such as in the case of touch panels, etc., where it is necessary to follow printing steps on touch panels, etc., and applications where it is necessary to follow moving living organisms.Specifically, touch panel applications. It can be used for optical applications such as electrical and electronic components, biological tapes, etc. Specific applications include, but are not limited to, optical adhesive sheets used in electronic devices such as smartphones, tablet PCs, and notebook computers, and protective tapes for electronic components. Among these, it can be suitably used for adhesion of various films inside the above-mentioned electronic devices.

Specific optical applications of optical adhesive sheets are not particularly limited, but include, but are not limited to, touch panels and displays for mobile phones, smartphones, tablets, foldable terminals, car navigation systems, personal computers, ticket vending machines, ITO films, and silver mesh. Examples include pressure-sensitive adhesive sheets used for adhesion of peripheral functional films such as , copper mesh, and polarizing plates. The operation method of the touch panel is not particularly limited, and a resistive film type, a capacitance type, an optical type, an ultrasonic type, an electromagnetic induction type, etc. can be suitably used.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention should not be construed as being limited by the following Examples unless the gist of the present invention is exceeded. In addition, 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 Examples and Comparative Examples
The properties of the polyalkylene oxide used in the Examples and Comparative Examples were determined by the following methods.
<Hydroxyl value and number average molecular weight of polyalkylene oxide>
The hydroxyl value of the polyalkylene oxide was measured according to 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>
The polyalkylene oxide, urethane prepolymer, or urethane-forming composition was subjected to GPC measurement 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.

To a sample bottle, an amount to give a solid content of 10 mg and 10 ml of THF were added, and the solution was dissolved by standing overnight, and a sample was obtained by filtering with a PTFE cartridge filter (0.5 μm). RI detector RI8020 was used as a detector, and TSKgel GMR-HHRL x 2 in series was used as a measurement column (both manufactured by Tosoh Corporation).
The measurement conditions were a column temperature of 40°C, a flow rate of 1.0 ml/min, and a solvent of THF.The number average molecular weight and weight average molecular weight were analyzed using a cubic approximate curve calibration curve using Tosoh's standard polystyrene. went. Further, the ratio Mw/Mn was defined as the molecular weight distribution. Tosoh's HLC-8320GPC was used as the measuring device, and Tosoh's HLC-8320GPC-ECOSEC-WorkStation was used for analysis.
<Unsaturation degree and average number of functional groups of polyalkylene oxide>
The degree of unsaturation of the polyalkylene oxide was measured by scanning 800 times in accordance with the NMR method described in Kobunshi Ronsenshu 1993, 50, 2, 121-126. Furthermore, the degree of unsaturation was converted into the amount of monool having an unsaturated group at one end, and the average number of actual functional groups of hydroxyl groups was calculated. Moreover, since the raw materials were known, the degree of unsaturation in the urethane prepolymer and the urethane-forming composition was calculated from the degree of unsaturation and the quantitative ratio of each polyalkylene oxide used.
<Ethylene oxide content (wt%)>
1H NMR was measured using a nuclear magnetic resonance apparatus (NMR) using deuterated chloroform containing tetramethylsilane as a heavy solvent. The ethylene oxide content in the polyol was calculated from the integral value in the range of 0.8 to 1.5 ppm (propylene oxide chain) and the integral value in the range of 3.2 to 3.9 ppm (propylene oxide chain and ethylene oxide chain).
<Primary ratio of hydroxyl groups>
Using a nuclear magnetic resonance apparatus (NMR), 1H NMR of a sample treated with trifluoroacetic anhydride was measured using deuterated chloroform containing tetramethylsilane as a heavy solvent. Integral value around 4.3 ppm of sample treated with trifluoroacetic anhydride (methylene bound to ester derived from primary OH group), integral value around 5.2 ppm (methine bound to ester derived from secondary OH group) The primary ratio of polyol hydroxyl groups was calculated from
(Raw material 1-1) Polyalkylene oxide (A1) used in Examples, polyalkylene oxide (AC1) used in Comparative Examples
Polyalkylene oxide (A1), (A3), (AC2): Using an imino group-containing phosphazenium salt (IPZ) catalyst and triisopropoxyaluminum together, sufficient dehydration and solvent removal are performed, and a bifunctional molecular weight of 400 is obtained. It was a polyoxypropylene glycol obtained by adding sufficiently dehydrated propylene oxide to polyoxypropylene glycol, and was a polyalkylene oxide having a small amount of primary hydroxyl groups.
Polyalkylene oxide (A2): Using a combination of imino group-containing phosphazenium salt (IPZ) catalyst and triisopropoxyaluminum, sufficient dehydration and solvent removal are performed to obtain polyoxypropylene glycol with a bifunctional molecular weight of 400. It was a polyoxyethylene propylene glycol to which ethylene oxide was added, and a polyalkylene oxide with a high proportion of primary hydroxyl groups.
Polyalkylene oxide (AC1), (AC3): Polyalkylene oxide produced by adding propylene oxide by a conventional method using a potassium hydroxide catalyst.
The properties of polyalkylene oxides (A1), (A2), (A3), and (AC2) are shown in Table 1, and all have extremely low amounts of unsaturated monools (very low degree of unsaturation) and narrow molecular weight distributions. It was a polyalkylene oxide that had a small amount or more of primary hydroxyl groups and was expected to shorten and suppress the induction period. In addition, (AC2) is a polyalkylene oxide with a relatively high viscosity due to its high molecular weight, and it is expected that the urethane prepolymer composition obtained mainly using it will have a constant viscosity, low thixotropy, and high solid content. It was a polyalkylene oxide that could not be used.

The properties of polyalkylene oxide (AC1) are shown in Table 1. It has a large amount of unsaturated monool (high degree of unsaturation) and a wide molecular weight distribution, and the urethane prepolymer composition obtained mainly by using it. The product was a polyalkylene oxide that could not be expected to have an unsaturation level of less than 0.020 meq/g and a molecular weight distribution of less than 1.50.

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

Polyalkylene oxide (B1-2), (B1-3): Commercially available trifunctional polyalkylene oxide, polypropylene oxide with a slightly lower degree of unsaturation due to its lower molecular weight.
Polyalkylene oxide (B1-4): Glycerin-initiated polyoxypropylene glycol with a trifunctional molecular weight of 400, prepared by using a combination of an imino group-containing phosphazenium salt (IPZ) catalyst and triisopropoxyaluminum, and thoroughly dehydrating and removing the solvent. It is a polyoxypropylene glycol to which sufficiently dehydrated propylene oxide is added, and it is a polypropylene oxide with significantly less unsaturated monool and a high actual average number of functional groups of approximately 3.

Polyalkylene oxide (BC1-1): A commercially available polyalkylene oxide, which has a high degree of unsaturation due to its high molecular weight, and contains polyalkylene oxide with three hydroxyl groups, but the actual average number of functional groups is close to 2. Polypropylene oxide It is.

Note that the polyalkylene oxides (A), (AC), (B1), and (BC-1) used in Examples and Comparative Examples were all used after being heated and dehydrated in vacuum. Furthermore, polyalkylene oxides prepared using or in combination with an IPZ catalyst were used after removing the catalyst.
(Raw material 2) Isocyanate compounds (C) and (I) used in Examples and Comparative Examples
Isocyanate (C1): 1,6-hexamethylene diisocyanate (HDI)
Isocyanate (C2): Isophorone diisocyanate (IPDI)
Isocyanate (I): Allophanate-modified bifunctional HDI crosslinking agent (Coronate 2770 manufactured by Tosoh Corporation)
(Raw material 3) Ketoenol tautomer compound (D) used in Examples and Comparative Examples
Ketoenol tautomer compound (D1): acetylacetone (raw material 4) additive urethanization catalyst: trisacetylacetonate iron (Fe(acac)3)
(Preparation of urethane prepolymer (E) and urethane prepolymer composition (G))
In a four-neck eggplant flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, a polyol such as polyalkylene oxide (A) and 10% of trisacetylacetonate iron (Fe(acac)3) as a urethanization catalyst were placed. % MEK masterbatch was added in the amount shown in the table in terms of solid content, and vacuum dehydration and solvent removal were performed at 100° C. for 2 hours.

After cooling, a predetermined amount of isocyanate compound (C) was added, and the reaction was carried out by raising the temperature to 70° C. substantially without solvent and without plasticizer. The amount of NCO groups in the contents of the reactor was monitored using an infrared spectrophotometer, and completion of the reaction was confirmed by the disappearance of NCO groups, thereby confirming the formation of urethane prepolymer (E). After cooling, polyalkylene oxide (B1) was added, and if necessary, a ketoenol tautomer compound (D) was added and mixed to obtain a urethane prepolymer composition (G).

The molecular weight distribution of the urethane prepolymer (E) was measured by GPC using tetrahydrofuran as a solvent and polystyrene as a standard substance before adding polyalkylene oxide (B1), and was calculated from the peak excluding the remaining polyalkylene oxide. The content of the remaining polyalkylene oxide (A) and urethane prepolymer (E) was calculated from the area ratio of the polyalkylene oxide component and the prepolymer component as determined above.
The number average molecular weight of the urethane prepolymer composition (G) was calculated by GPC using tetrahydrofuran as a solvent and polystyrene as a standard substance after adding the polyalkylene oxide (B1) and before adding the ketoenol tautomer compound (D1).

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

The content of each component in the urethane prepolymer composition (G) is determined by the content of the urethane prepolymer (E) and the remaining polyalkylene oxide component, and the weight of the added polyalkylene oxide and ketoenol tautomer compound (D1). More calculated. Note that the composition ratio was calculated without taking into account the urethane-forming catalyst that may be used when forming the urethane prepolymer and the absorbed moisture, since the amount of absorbed water was very small.
(Preparation of urethane-forming composition (H) and cured urethane product (I))
In the Examples and Comparative Examples, a predetermined amount of each raw material (urethane prepolymer composition (G), isocyanate (F)) was placed in a 30 ml sample bottle, and by stirring and defoaming at room temperature using a pencil mixer. A urethane-forming composition (H) was obtained.
(Performance evaluation)
The urethane-forming composition (H) was applied onto a PET film having a thickness of 38 μm using a Baker applicator so that the thickness after drying was 80 μm. Thereafter, the oven was kept in an explosion-proof oven set at 130°C for 5 minutes to remove volatile matter and advance the curing reaction, forming a cured urethane material (I) on the PET film and releasing the mold-release PET. They were pasted together to form a three-layer sheet structure. Thereafter, the polyurethane sheet was obtained by allowing it to stand for one week in an environment of 23° C. and 50% relative humidity.

In the process, the urethane prepolymer composition (G) and the urethane-forming composition (H) were evaluated based on the following evaluation criteria as performance indicators.
<High solid differentiation>
◎ (Low VOC pass): Non-volatile content of 99% or more and viscosity at 25°C of 1.5 to 20 Pa・s ○ (Low VOC pass): ◎ Non-volatile content of 80% or more and at 25°C, excluding judgment Viscosity in the range of 0.1 to 30 Pa·s x (low VOC failure): Non-volatile content is less than 80% or 80% or more and the viscosity at 25°C is outside the range of 0.1 to 30 Pa·s. It is considered difficult to reduce VOC because it has a high solid content and does not have a constant viscosity.
<Curability>
◎ (Cureability passed): High cohesive force is developed immediately after curing at 130°C for 5 minutes, and no adhesive remains on fingers when touched.
○ (Cureability passed): Adhesive remains on the finger when touched immediately after curing at 130°C for 5 minutes, but the adhesive remains after one week of aging at 23°C and 50% relative humidity after bonding the release PET. Does not spread and leaves no adhesive on your fingers when you touch it.
× (Failure of curing): After curing at 130℃ for 5 minutes and aging for one week at 23℃ and 50% relative humidity after laminating the release PET, the adhesive spreads on the finger when touched. There's nothing left. It was determined that curing was slow.
XX (curability 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 the release PET, adhesive remains on the finger when touched. It was determined that the curing was insufficient.
<Moldability>
◎ (Moldability passed): Curability evaluation is ◎, and there is no repellency during coating and curing, and thickness unevenness due to flow is within 5%.
○ (Moldability passed): Curability evaluation is ○, and there is no repellency during coating and curing, and thickness unevenness due to flow is within 5%.
× (Failure of moldability): The evaluation of hardenability is ◯ or higher, and the thickness unevenness due to flow is more than 5%. It was determined that the coating was defective and the liquid was likely to flow due to high temperatures during curing.
XX (Failure of moldability): Other than the above (curability evaluation is × or less, thixotropy index is high and coatability is poor, etc.).
<Pot life>
◎ (Pot life: Remarkably good): The viscosity increase rate is 20% or less after 48 hours after mixing the curing agent.
○ (Pot life: Good): After mixing the curing agent, the viscosity increase rate is 20% or less after 24 hours, and the viscosity increase rate after 48 hours is over 20%.
Δ (Pot life: Normal): After mixing the curing agent, the viscosity increase rate is 20% or less after 10 hours, and the viscosity increase rate after 24 hours is over 20%.
× (Poor pot life): The viscosity increase rate exceeds 20% after 10 hours after mixing the curing agent.
The mixing and standing were performed at 23°C, and the viscosity was measured at 25°C using a B-type viscometer.

A urethane that can be highly solidified at a constant viscosity, exhibits good curability, and contributes to the formation of cured urethane products with low environmental impact and high cohesive strength, if it passes the criteria of high solidification, curability, and moldability. They were determined to be a prepolymer composition (G) and a urethane-forming composition (H).
Furthermore, we judged that those with a pot life of ◎ not only have good curability but also have a characteristically long pot life. It was judged that the urethane prepolymer composition (G) and the urethane-forming composition (H) were excellent in productivity.

Further, the physical properties of the coating film of the cured urethane product (I) obtained in the above step were evaluated using the following evaluation criteria, and used as an index of performance.
<Removability>
20 minutes after pasting on alkali-free glass, peeling was performed at 300 mm/min and the peeling condition was evaluated. Furthermore, Nitto Denko's 31B tape was pasted on the peeled adherend glass three times with a 5 kg roller, and after standing still for 20 minutes, the peeling force was measured at 300 mm/min, and the ratio with the 31B tape peeling force on a clean glass surface was measured. was evaluated as the residual adhesion rate (31B peel force on a glass surface after re-peeling the urethane cured product/31B peel force on a clean glass surface).
◎ (removability passed): There is no visible stain or adhesive residue, and the residual adhesion rate is in the range of 90 to 110%.
○ (removability passed): There is no visible stain or adhesive residue, and the residual adhesion rate is less than 90% or more than 110%. It is removable, and although there is a very small amount of components that change the adhesive strength remaining, it is judged to be relatively good.
× (removability failed): When visual contamination such as visual contamination, some adhesive residue, or clouding clearly occurs. It was determined that re-peel was added due to contamination of the adherend.
XX (hardening failure): When adhesive residue is generated due to cohesive failure.
<Flexibility>
In the performance evaluation section above, a urethane sheet was prepared using double-sided release molded PET, and only the obtained cured urethane product was taken out and its dynamic viscoelasticity was measured in shear mode. G') was evaluated using the following criteria. This was used as an index for level difference followability and bending followability.
◎ (Flexibility passed): 3.0×10 ⁴ Pa or more, 2.0×10 ⁵ Pa・s or less.
○ (Flexibility passed): More than 2.0×10 ⁵ Pa・s, 3.0×10 ⁵ Pa・s or less.
× (Flexibility failure): More than 3.0×10 ⁵ Pa·s.
*In this evaluation, there were no test pieces with elastic modulus outside the above range.
<Cold resistance>
◎ (Cold resistance passed): Tg -80℃ or higher to -50℃ or lower.
○ (cold resistance passed): Tg over -50℃ to -30℃ or less.
× (Failure of cold resistance): Tg exceeding -30°C.
*In this evaluation, there were no test pieces with glass transition points (Tg) outside the above range.
<Practical characteristics>
◎ (Practical properties passed): Adhesive strength is 0.5 to 10 N/25 mm, and retention strength is less than 1 mm for 24 hours or more.
○ (Practical properties passed): Adhesive strength is between ◎ and ×, and holding power is 100 minutes or more.
× (Practical properties failed): Adhesive force is less than 0.1 N/25 mm or 30 N/25 mm, or holding force is less than 100 minutes.
<Ball tuck>
◎ (Possesses cohesive force and remarkably good wettability): 21 or more ○ (Good): 6 or more and 20 or less × (Normal): 5 or less Good removability, flexibility, cold resistance, and practical properties. Those that passed the test were judged to be cured urethane products (I) with excellent cohesive strength, remarkably good flexibility and cold resistance, and were used to produce urethane sheets that were expected to have good adhesive properties and stain resistance upon re-peeling. It was determined that this is a cured urethane product that can be expected to be developed.

Furthermore, we determined that those with ball tack of ◎ not only have good physical properties of the coating film but also have significantly good wettability in addition to cohesive force, and characteristically exhibit high adhesive strength instantly. The urethane cured product (I) was determined to be a urethane sheet that exhibits various physical properties, has particularly good wettability to adherends, and is particularly promising for bending, deformation, tracking of printing steps, etc.
<Urethane prepolymer synthesis example 1>
In Synthesis Example 1, 100 parts by weight of polyalkylene oxide (A1) and a 10% methyl ethyl ketone solution of iron trisacetylacetonate as a urethanization catalyst were mixed as a masterbatch so that the iron component of trisacetylacetonate was 0.02 parts by weight. The polyol composition and isocyanate compound (C1), which were dehydrated and desolvated under reduced pressure at 100°C for 2 hours, were divided into the amount of hydroxyl groups derived from (A1) (M _OH ) and the amount of isocyanate groups derived from (C1). The reaction was carried out at a molar ratio of (M _NCO ) of (C1) M _NCO /((A1) M _OH )=0.40 and the temperature was raised to 70°C.

The amount of NCO groups in the contents of the reactor was monitored using an infrared spectrophotometer, completion of the reaction was confirmed by the disappearance of NCO groups, and a composition containing the urethane prepolymer (E1) was obtained.
The composition was analyzed by GPC method and was found to be a composition containing 32 area% of unreacted polyalkylene oxide (A1) and 68 area% of urethane prepolymer (E1) having urethane groups. The molecular weight distribution of component (E1) was less than 1.35, which was a significantly narrow dispersity.

Because the reaction is performed after dehydrating and removing solvents from the raw materials, the composition is virtually solvent-free, with a combined residual solvent and water content of less than 1000 ppm, and the degree of unsaturation calculated from the raw materials used is 0.0018 meq/g. were significantly less.
<Production Example 1 of urethane prepolymer composition and urethane-forming composition>
The 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, and 0.0% of the ketoenol tautomer compound (D1). A polyalkylene oxide (B1-1) containing 3% by weight and 3 hydroxyl groups was mixed at a ratio of 15% by weight to obtain a urethane prepolymer composition (G1).

The urethane prepolymer composition (G1) contains a total of 42.1% by weight of polyalkylene oxide (A1) and polyalkylene oxide containing three hydroxyl groups (B1-1) as a polyalkylene oxide component, and contains 42.1% by weight of polyalkylene oxide (A1) and polyalkylene oxide (B1-1) containing three hydroxyl groups. The calculated degree of unsaturation was 0.0056 meq/g, which showed that the monool component capable of capping the terminals was significantly small. In addition, a volatile ketoenol tautomer compound (D1) is added at a concentration of 0.3% by weight, and the non-volatile concentration of this composition is significantly high at 99.7% by weight, resulting in low VOC. It was something to look forward to.

The urethane prepolymer composition (G1) was analyzed by the GPC method and showed a bimodal distribution of two components, the urethane prepolymer (E1) component and the polyalkylene oxide component, and the number average molecular weight of the two components was 14,800 and 8,000. It has an appropriate molecular weight that is less than 40,000 and is suitable for coating with high solids content, does not become highly viscous even with high solids content, and can be expected to maintain a constant viscosity from room temperature to drying temperature during coating. there were. The urethane prepolymer composition (G1) had a constant viscosity at 25° C. with a high solids content of 9.6 Pa·s, and also had a sufficiently low thixotropy index of 1.03.

By mixing the isocyanate compound (F1) having an allophanate group in a ratio such that the amount of NCO groups is 1.3 equivalents with respect to the total amount of hydroxyl groups in the obtained urethane prepolymer composition (G1), a urethane-forming composition is obtained. Product (H1) was produced. The urethane-forming composition (H1) has a viscosity of 8.2 Pa·s at 25°C, a constant viscosity with a high solids content, and has excellent handling properties during coating and curing with a high solids content. Ta.

In addition, in Synthesis Example 1 and Production Example 1, trisacetylacetonate iron was added as a masterbatch using a solvent and the solvent was removed to make it solvent-free, but it was added as a powder without using a solvent, dehydrated and It can be produced in the same manner by removing the solvent, and the same properties as the urethane prepolymer composition and the same properties as the cured urethane product were obtained.

(Synthesis examples 2 to 16)
In Synthesis Examples 2 to 16, various raw materials were changed, and urethane prepolymers were synthesized and properties evaluated in the same manner as in Synthesis Example 1. Table 3 below shows the raw material composition and properties of the compositions containing the synthesized urethane prepolymers (E) and (EC).

In Synthesis Examples 2, 4 to 7, and 9, which were synthesized by changing various raw materials, the degree of unsaturation calculated from the raw materials used was significantly lower, similar to Synthesis Example 1, and the monool component that can end-capped was significantly lower. The molecular weight distribution of the urethane prepolymer (E) component containing unreacted polyalkylene oxide and having urethane groups was less than 1.35, which was a significantly narrow degree of dispersion.
For Synthesis Example 1, Synthesis Example 3 has an NCO/OH ratio of 0.60 and the polymer chain is slightly extended, and a small amount of 10 parts of high molecular weight polyalkylene oxide (B1-1) having three hydroxyl groups is used instead. Synthesis Example 8, in which the NCO/OH ratio was 0.15 and the polymer chain was prepolymerized, had a slightly wider molecular weight distribution than Synthesis Example 1, but it was narrower in the range of 1.35 to less than 1.50. The degree of dispersion was maintained.

Synthesis Examples 10 and 11 are synthesis examples in which chain extension was performed using polyalkylene oxide (AC1) with a high degree of unsaturation. The degree of dispersion was wide, possibly due to the effects of silencing and by-products.
Synthesis Example 12 is a polyalkylene oxide with three hydroxyl groups as the main component, which is chain-extended using only polyalkylene oxide (B1-1) containing a certain amount of unsaturated monool. There was a broadening of the molecular weight distribution, which is thought to be due to the influence of odor.
Synthesis Example 14 uses a solvent designed in the prior art, and uses a combination of a bifunctional polyalkylene oxide (AC2) with a relatively high molecular weight of 29,000 and a trifunctional polyalkylene oxide to form a prepolymer with a high molecular weight and increase the cohesive force. Although it is a design with a high degree of unsaturation and a high molecular weight that can be expected to have good stain resistance, the molecular weight distribution was wide at over 5.5 and the solid content was low.

In Synthesis Example 15, in order to achieve lower VOC than Synthesis Example 14, the non-volatile content concentration was greatly increased from 30% to 80%, resulting in a gel-like material.

In Synthesis Example 16, a relatively high molecular weight polyalkylene oxide (A1) and polyisocyanate (C2) were used at an NCO/OH ratio of 2.7 to form an NCO-terminated urethane prepolymer in the first stage, and then in the second stage. The design uses a two-stage polymerization method in which a large amount of low-molecular-weight polyalkylene oxide (AC2) with a molecular weight of 400 and a large amount of hydroxyl groups is added to greatly increase the amount of urethane groups and impart cohesive strength. The composition contained 38 area% of alkylene oxide (AC2) alone, and the urethane prepolymer (EC6) also had a broader molecular weight distribution than Synthesis Example 1.

The urethane prepolymers (E1) to (E9) used in the examples all had polyols with a low average functional group number in the range of 1.90 to 2.20, a narrow molecular weight distribution, and a weight average molecular weight of 8000 or more. It was found that the urethane prepolymer composition (G) easily achieved both good thixotropy and a constant viscosity, and easily had excellent moldability at a high solid content.

(Production Example 1, Example 1)
Example 1 using the urethane-forming composition (H1) containing the urethane prepolymer composition (G1) obtained in Production Example 1 is shown in Table 5, and the nonvolatile content concentration is remarkable at 99.7%. The urethane prepolymer (E1) has a constant viscosity of 8.2 Pa・s at 25°C, and the urethane prepolymer (E1) has a narrow molecular weight distribution and low thixotropy, making it easy to coat. Because of its low degree of unsaturation, it exhibited excellent curability when volatile matter was removed and a curing reaction was carried out in an explosion-proof oven at 130°C for 5 minutes.

In addition, since the urethane-forming composition (H1) contains polyalkylene oxide (B1-1) containing three or more hydroxyl groups alone rather than in a prepolymer and the molecular weight of the polyfunctional component is small, a small amount of ketoenol tautomer Regardless of the amount of the compound used, the increase in viscosity immediately after adjustment was remarkably gradual, and the rate of increase in viscosity after 72 hours was 20% or less, indicating a significantly excellent pot life.

Furthermore, the coating film of the obtained cured urethane product (I1) contains polyalkylene oxide (B1-1) containing three or more hydroxyl groups alone in the urethane-forming composition, leaving crosslinking points in the cured urethane product. It is easy to form a loose network with few defects due to the small amount of unsaturated monool that seals the ends, and the storage modulus at 25°C is 1.0 × 10 ⁵ Pa, which is extremely flexible. There was no adherend contamination or adhesive residue, and re-peelability was possible. In addition, the glass transition temperature was extremely low at -56°C, indicating excellent low-temperature properties, and good cold resistance that could be expected to improve impact peeling resistance at low temperatures.

In addition, the cured urethane product obtained with the above design exhibits a significantly high ball tack of 32 or more, and has excellent wettability while maintaining cohesive force, so it instantly develops adhesive properties to adherends, and has the following characteristics: It was a cured urethane product (I1) that could be expected to have good deformation and movement such as bending, and followability to steps and the like.

(Production Examples 2-7, Examples 2-7)
Production Examples 2 to 7 are urethane prepolymers containing the same urethane prepolymer (E1) as Production Example 1, but by changing the type and quantity ratio of the polyalkylene oxide (B) containing three or more hydroxyl groups. This is an example of producing polymer compositions (G2) to (G7) and urethane-forming compositions (H2) to (H7). The compositions and properties are shown in Table 4. Urethane prepolymer compositions (G2) to (G7) all contain polyalkylene oxide (B1) having three or more hydroxyl groups and urethane prepolymer (E), and are unsaturated. The total amount of bases was significantly low, and the nonvolatile content concentration of this composition was significantly high at 99.5% by weight or more, and low VOC could be expected.

The urethane prepolymer compositions (G2) to (G7) were analyzed by the GPC method and showed a two- to three-modal distribution of the urethane prepolymer (E) component and the polyalkylene oxide component, and the combined number It had an average molecular weight of 8,000 or more and less than 40,000, had a moderate molecular weight, did not become highly viscous even with a high solid content, and could be expected to have a constant viscosity from room temperature at the time of coating to drying temperature. The viscosity of the urethane prepolymer compositions (G2) to (G7) at 25°C is in the range of 1 to 20 Pa·s, and the viscosity is high and constant, and the thixotropy index is also 1.2 or less. was sufficiently low.

By mixing the isocyanate compound (F) in a ratio such that the amount of NCO groups is 1.3 equivalents with respect to the total amount of hydroxyl groups of the obtained urethane prepolymer compositions (G2) to (G7), a urethane-forming composition is obtained. Products (H2) to (H7) were produced.

Examples 2 to 7 using urethane-forming compositions (H2) to (H7) are shown in Table 5, and in all of them, the nonvolatile content concentration was significantly high at 99.5% by weight or more, making it possible to reduce VOC. It has a constant viscosity in the range of 1 to 20 Pa・s at 25°C, and the urethane prepolymer has a narrow molecular weight distribution and low thixotropy, so it has excellent coating properties and has a low degree of unsaturation. Therefore, it exhibited excellent curability when volatile matter was removed and the curing reaction was carried out in an explosion-proof oven at 130°C for 5 minutes.

In addition, since the urethane-forming compositions (H2) to (H7) contain polyalkylene oxide (B1) containing three or more hydroxyl groups alone rather than in a prepolymer and the molecular weight of the polyfunctional component is small, all of them are present in small amounts. Despite the amount of ketoenol tautomer compound used, the increase in viscosity immediately after adjustment was significantly slow, and the rate of increase in viscosity after 48 hours was less than 20%, which resulted in a significantly superior pot life. .

Further, the coating films of the obtained cured urethane products (I2) to (I7) contain polyalkylene oxide (B1) containing three or more hydroxyl groups solely in the urethane-forming composition, and the crosslinking points in the cured urethane product are The urethane-forming compositions (H2) to (H6) all have 2.0×10 ⁵ It is flexible with Pa or less, can be re-peeled without staining or adhesive residue, and has a significantly low glass transition temperature of -50°C or less, giving it excellent low-temperature properties. (H7), which contained a large amount of polyalkylene oxide containing three or more hydroxyl groups at 50 parts by weight, had slightly lower flexibility than (H2) to (H6), but it was less than 3.0 × 10 ⁵ Pa・s. It exhibited somewhat good flexibility, was removable without staining or adhesive residue, and had a significantly low glass transition temperature of -50° C. or less, exhibiting excellent low-temperature properties.

The cured urethane products (I2) to (I7) obtained with the above design all exhibit high ball tack properties and have excellent wettability while maintaining cohesive force, so they instantly develop adhesive properties to adherends. It was a cured urethane product (I) that could be expected to have good followability.

(Production Examples 8-9, Examples 8-9)
Production Examples 8 to 9 are different from Production Example 1 to the urethane prepolymer (E1) obtained in Synthesis Example 2, which has a lower NCO/OH ratio when forming the urethane prepolymer from the prepolymer (E1) obtained in Synthesis Example 1. This is an example produced by changing to urethane prepolymer composition (E2), in which the amount of unreacted polyalkylene oxide (A1) in the composition is large and the amount ratio of urethane prepolymer (E) is low. G8), (G9), and urethane-forming compositions (H8) and (H9). The composition and properties are shown in Table 4, and both urethane prepolymer compositions (G8) and (G9) contain polyalkylene oxide (B1) having three or more hydroxyl groups and urethane prepolymer (E), and are unsaturated. The total amount of bases was significantly low, and the nonvolatile content concentration of this composition was significantly high at 99.5% by weight or more, and low VOC could be expected.

Examples 8 and 9 using urethane-forming compositions (H8) and (H9) are shown in Table 5, and both have significantly high nonvolatile content concentrations of 99.5% by weight or more, making it possible to reduce VOC. However, since the amount of unreacted polyalkylene oxide (A1) in the composition is large and the amount ratio of urethane prepolymer (E) is low, the moldability during coating is lower than that of (H1) to (H7). Although it decreased slightly, the viscosity at 25°C was in the range of 1 to 20 Pa·s, which was a constant viscosity, and the urethane prepolymer had a narrow molecular weight distribution and low thixotropy, so the coating properties were generally good. Because of its low degree of unsaturation, it had excellent curability when volatile matter was removed and the curing reaction was carried out in an explosion-proof oven at 130°C for 5 minutes.

(Production Examples 10-11, Examples 10-11)
Production Examples 10 to 11 were obtained in Synthesis Example 3, in which the NCO/OH ratio was higher when forming the urethane prepolymer from the prepolymer (E1) obtained in Synthesis Example 1, compared to Production Example 1. ) This is an example of manufacturing by changing to a urethane prepolymer (E3) with a slightly wider molecular weight distribution than that of urethane prepolymer compositions (G10), (G11), urethane-forming compositions (H10), (H11). It is. Table 4 shows the composition and properties, and both urethane prepolymer compositions (G10) and (G11) contain polyalkylene oxide (B1) having three or more hydroxyl groups and urethane prepolymer (E), and are unsaturated. The total amount of bases was significantly low, and the non-volatile concentration of this composition was significantly high at 99.5% by weight or more, and low VOC could be expected.

Examples 10 and 11 using urethane-forming compositions (H10) and (H11) are shown in Table 5, and in both cases, the nonvolatile content concentration was significantly high at 99.5% by weight or more, making it possible to reduce VOC. Yes, because the molecular weight distribution of the urethane prepolymer (E3) was slightly wider than that of (E1), the moldability during coating was slightly lower than that of (H1) to (H7), but the viscosity at 25°C was 20 to 30 Pa.・The urethane prepolymer has a constant viscosity in the range of Excellent curing properties when the volatile matter was removed and the curing reaction was carried out in an explosion-proof oven.

(Production Examples 12-19, Examples 12-19)
Production Examples 12 to 19 differ from Production Example 1 in that the type was changed from the prepolymer (E1) obtained in Synthesis Example 1 to the urethane prepolymer obtained in Synthesis Examples 4 to 9, and the amount of the ketoenol tautomer compound was changed. , urethane prepolymer compositions (G12) to (G19), urethane-forming compositions obtained by adjusting the ratio of the amount of polyalkylene oxide (B1) used according to the molecular weight of the polyalkylene oxide (B1) used in combination (H12) to (H19). The composition and properties are shown in Table 6, and the urethane prepolymer compositions (G12) to (G7) all contain a polyalkylene oxide (B1) having three or more hydroxyl groups and a urethane prepolymer (E), and are unsaturated. The total amount of bases was significantly low, and the nonvolatile content concentration of this composition was significantly high at 99.5% by weight or more, and low VOC could be expected.

The urethane prepolymer compositions (G12) to (G19) were analyzed by the GPC method and showed a two- to three-modal distribution of the urethane prepolymer (E) component and the polyalkylene oxide component, and the combined number It had an average molecular weight of 8,000 or more and less than 40,000, had a moderate molecular weight, did not become highly viscous even with a high solid content, and could be expected to have a constant viscosity from room temperature at the time of coating to drying temperature. The viscosity of the urethane prepolymer compositions (G12) to (G19) at 25°C is in the range of 1 to 20 Pa·s, and they have a high solid content and a constant viscosity, and the thixotropy index is also 1.2 or less. was sufficiently low.

By mixing the isocyanate compound (F1) at a ratio such that the amount of NCO groups is 1.3 equivalents with respect to the total amount of hydroxyl groups of the obtained urethane prepolymer compositions (G12) to (G19), a urethane-forming composition can be obtained. Products (H12) to (H19) were produced.

Examples 12 to 19 using urethane-forming compositions (H12) to (H19) are shown in Table 7, and in all of them, the nonvolatile content concentration was significantly high at 99.5% by weight or more, making it possible to reduce VOC. It has a constant viscosity in the range of 0.1 to 30 Pa・s at 25°C, and the urethane prepolymer has a narrow molecular weight distribution and low thixotropy, so it has excellent coating properties and has a low degree of unsaturation. Because of its low temperature, it exhibited excellent curability when volatile matter was removed and the curing reaction was carried out in an explosion-proof oven at 130°C for 5 minutes.

In addition, since the urethane-forming compositions (H12) to (H19) contain polyalkylene oxide (B1) containing three or more hydroxyl groups alone rather than in a prepolymer and the molecular weight of the polyfunctional component is small, all of them are present in small amounts. Despite the amount of ketoenol tautomer compound used, the increase in viscosity immediately after adjustment was significantly slow, and the rate of increase in viscosity after 48 hours was less than 20%, which resulted in a significantly superior pot life. .

Furthermore, the coating films of the obtained cured urethane products (I12) to (I19) contain polyalkylene oxide (B1) containing three or more hydroxyl groups alone in the urethane-forming composition, and the crosslinking points in the cured urethane product are urethane-forming compositions (H12), (H13), and (H15) to (H19). It was also extremely flexible, with a strength of 2.0×10 ⁵ Pa or less, and could be re-peeled without staining or adhesive residue, and the glass transition temperature was also extremely low, at -50° C. or less, giving it excellent low-temperature properties.

Polyalkylene oxide (B1) containing three or more hydroxyl groups has a short molecular weight of 1900 and a relatively high molecular weight of 20 parts by weight, which tends to increase the number of crosslinking points (H14), which is slightly more flexible than (H2) to (H6). However, it exhibits somewhat good flexibility at 3.0×10 ⁵ Pa・s or less, can be re-peeled without staining or adhesive residue, and has a significantly low glass transition temperature of -50°C or less. Excellent characteristics.

In addition, the total amount of single polyalkylene oxide (B) including polyalkylene oxide (B1) is relatively large at 69.4 to 75.9% by weight, and the prepolymer (E) content is relatively small (H16) to (H19). has a high solids content and a constant viscosity, but because it contains more polyalkylene oxide components with lower molecular weight than the prepolymer component, the liquid flows slightly more easily during coating and curing reactions than (H2) to (H6). Furthermore, in (H16), which contained a small amount of polyalkylene oxide (B1) having three or more hydroxyl groups at 1% by weight, the curability was slightly lower than that in (H2) to (H6), but all had good moldability. , showed curability.

The cured urethane products (I12) to (I19) obtained with the above design have excellent wettability while maintaining cohesive strength, so they all exhibit significantly high ball tack properties and instantly develop adhesive properties to adherends. However, it was a cured urethane product with a characteristically high followability.

In addition, both the urethane prepolymer composition (G) and the urethane-forming composition (H) obtained in the above examples do not contain a large amount of plasticizer, exhibit high compatibility, are liquid and do not separate, and the cured urethane composition All had haze of less than 2% and were highly transparent.

Furthermore, neither the urethane prepolymer composition (G) nor the urethane-forming composition (H) obtained in the above examples intentionally contained a urethanization catalyst, etc., and contained 10% by weight or more of a solvent as a manufacturing raw material. In addition to being able to be manufactured without containing any substances and having a significantly lower environmental impact, the work environment was also significantly better.

(Production Example 20, Comparative Example 1)
Production Example 20 is a production example that contains the same urethane prepolymer (E1) as Production Example 1 but does not contain the polyalkylene oxide (B1) having three or more hydroxyl groups, and the urethane prepolymer composition ( GC1), a urethane-forming composition (HC1).
Comparative Example 1 using the urethane-forming composition (HC1) is shown in Table 9, and like Production Example 1, it contains a urethane prepolymer (E1) consisting of a polyalkylene oxide with a significantly low degree of unsaturation. The degree of unsaturation calculated from the raw materials is 0.0018 meq/g, which is a significantly low amount of monool components that can cap the terminals, and the concentration of nonvolatile matter is significantly high at 99.7% by weight, and the number average molecular weight is 27,600. 8,000 or more and less than 40,000, it has an appropriate molecular weight, does not become highly viscous even with a high solid content, and can be expected to have a constant viscosity from the room temperature at the time of coating to the drying temperature. Since it does not contain the polyalkylene oxide (B1) having the above hydroxyl groups, it has poor curability and insufficient moldability, making it difficult to use.

Furthermore, the obtained cured urethane product (IC1) does not contain polyalkylene oxide (B1) having three or more hydroxyl groups, so it has high flexibility but lacks cohesive strength and leaves adhesive residue when peeled off, resulting in poor staining properties. It was difficult to use, and although the wettability was good, the cohesive force was insufficient and the ball tack was low, so the followability could not be expected.

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

Comparative Examples 2 and 3 using urethane-forming compositions (HC2) and (HC3) are shown in Table 9, and like Production Example 1, urethane preforms made of polyalkylene oxide with a significantly low degree of unsaturation were used. The degree of unsaturation of the urethane prepolymer composition (GC2) calculated from the raw materials used is The amount exceeds 0.020 meq/g, 0.027 meq/g, and 0.023 meq/g, which means that there are many monool components that can block the terminals, and the curability and moldability are also insufficient, making it difficult to use.

In addition, the obtained urethane cured products (IC2) and (IC3) have a degree of unsaturation in the urethane prepolymer composition exceeding 0.020 meq/g and contain many monool components that can block terminals. It was difficult to use because it had poor cohesive force and staining properties, and some adhesive residue and staining occurred on the adherend upon re-peeling.

(Production Example 23, Comparative Example 4)
Production Example 23 differs from Example 1 in Production Example 1 in that the urethane prepolymer (E1) is changed to a urethane prepolymer (E2) containing a large amount of unreacted polyalkylene oxide (A1), and further contains three or more hydroxyl groups. A urethane prepolymer composition (GC4) in which the content of polyalkylene oxide (B) in the urethane prepolymer composition is more than 79% by weight, which contains as much as 50% by weight of polyalkylene oxide (B1-1) having It is a urethane-forming composition (HC4).

Comparative Example 4 using the urethane-forming composition (HC4) is shown in Table 9, and as in Production Example 1, it contains a urethane prepolymer made of polyalkylene oxide with a significantly low degree of unsaturation, and the amount calculated from the raw materials used. The degree of unsaturation is 0.0119 meq/g, which is low in monool components that can cap the terminals, and the concentration of nonvolatile matter is significantly high at 99.7% by weight. However, polyalkylene oxide, which easily acts as a diluent, (B) in a range exceeding 79% by weight and the content of the urethane prepolymer, which tends to maintain a constant viscosity even at high temperatures, is as low as 13.4% by weight, resulting in strong liquid flow during coating and curing reactions. It had poor moldability and was difficult to use.

In addition, the obtained cured urethane product (IC4) has a degree of unsaturation in the urethane prepolymer composition (GC4) of less than 0.020 meq/g and contains polyalkylene oxide (B1) containing three or more hydroxyl groups, so it cannot be recycled. The peelability was good, but since a large amount of polyalkylene oxide (B) containing a large amount of polyalkylene oxide (B1) having three hydroxyl groups was used, the flexibility was insufficient and the followability was poor. It was difficult to develop it into necessary applications, and its ball tack properties were also insufficient.

(Production Examples 24 and 25, Comparative Examples 5 and 6)
Production Example 24 differs from Example 1 in Production Example 1 in that the urethane prepolymer (E1) obtained using a polyalkylene oxide with a significantly low degree of unsaturation is changed from the urethane prepolymer (E1) obtained using a polyalkylene oxide with a high degree of unsaturation. Urethane prepolymer compositions (GC5), (GC5), urethane-forming compositions (HC5), and (HC6) were produced by changing the obtained urethane prepolymer (EC1).

Comparative Examples 5 and 6 using urethane-forming compositions (HC5) and (HC6) are shown in Table 9, but like Production Example 1, polyalkylenes having three or more hydroxyl groups with a low degree of unsaturation were used. Although it contains oxide (B1), since it contains a large amount of urethane prepolymer (EC1) obtained using polyalkylene oxide with a high degree of unsaturation, the degree of unsaturation of the urethane prepolymer composition (GC5) calculated from the raw materials used is Regardless of the type and amount of polyalkylene oxide (B1), since it has a large amount of unsaturated monool components that cap the terminals during crosslinking with 0.1116 and 0.0452 meq/g exceeding 0.020 meq/g, The curability and moldability used were also insufficient, making it difficult to use.

(Production Example 26, Comparative Example 7)
Production Example 26 is a production example containing a polyalkylene oxide (B1) having three or more hydroxyl groups but not containing a urethane prepolymer (E), a composition (GC7), a urethane-forming composition (HC7) It is. The degree of unsaturation of the composition (GC7) calculated from the raw materials used is less than 0.020 meq/g, but it does not contain a urethane prepolymer component containing urethane groups, and the number average molecular weight of the composition is as low as less than 8000, making it difficult to coat. The liquid flowed violently during the processing and curing reactions, resulting in poor moldability and difficulty in use.

The obtained urethane cured product (IC7) has a degree of unsaturation in the urethane prepolymer composition of less than 0.020 meq/g, and contains a polyalkylene oxide (B1) containing three or more hydroxyl groups, but does not contain a urethane prepolymer component. Because it does not contain any of the following, removability was good, but flexibility and ball tack were reduced, making it difficult to apply it to applications that require followability.

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

Comparative Example 8 using the urethane-forming composition (HC8) is shown in Table 9, and contains a polyalkylene oxide (B1) having three or more hydroxyl groups with a low degree of unsaturation in the prepolymer or alone. Since it contains a large amount of urethane prepolymer (EC2) obtained by using a large amount of polyalkylene oxide with a high degree of unsaturation, the degree of unsaturation of the urethane prepolymer composition (GC8) calculated from the raw materials used exceeds 0.020 meq / g 0.1115 meq/g and contains a large amount of unsaturated monool components that end-block during crosslinking, so even if polyalkylene oxide (B1) having three or more hydroxyl groups is used in the prepolymer, the curability will be low. It is difficult to use due to insufficient moldability and moldability.Furthermore, because the prepolymer contains a large amount of polyalkylene oxide (B1) having three or more hydroxyl groups, the molecular weight distribution is wide and it exhibits a significantly good pot life. I didn't.
The resulting cured urethane product (IC8) also had insufficient stain resistance and flexibility, making it difficult to apply it to applications requiring removability and conformability.

(Production Example 28, Comparative Example 9)
Production Example 28 is a urethane prepolymer (EC3) consisting of a polyol with an average number of functional groups exceeding 2 functional groups using a polyalkylene oxide (B1-1) with a slightly lower degree of unsaturation, and a polyol with a slightly lower degree of unsaturation. These are a urethane prepolymer composition (GC9) and a urethane-forming composition (HC9) produced using alkylene oxide (B1-1).

Comparative Example 9 using the urethane-forming composition (HC9) is shown in Table 9, and both the urethane prepolymer (EC3) and polyalkylene oxide (B1) have a slightly lower degree of unsaturation, but the degree of unsaturation is calculated from the raw materials used. The overall degree of unsaturation of the urethane prepolymer composition (GC9) exceeds 0.020 meq/g. Because it contains an unsaturated monool component that seals the terminals, the moldability is insufficient and it is difficult to use. Since the prepolymer contained a large amount of the polyalkylene oxide (B1) having the above hydroxyl groups, the molecular weight distribution was wide and the pot life was not particularly good.
The obtained cured urethane product (IC9) also has insufficient stain resistance, removability, and flexibility because the degree of unsaturation of the entire urethane prepolymer composition (GC9) exceeds 0.020 meq/g, and it cannot be recycled. It has been difficult to develop it into applications that require peelability and followability.

(Production Example 29, Comparative Example 10)
Production Example 29 is a composition (GC10) produced by mixing a polyalkylene oxide (A) with a significantly low degree of unsaturation with a polyalkylene oxide (B1) having three or more hydroxyl groups without prepolymerizing it. , a urethane-forming composition (HC10).
Comparative Example 10 using the urethane-forming composition (HC10) is shown in Table 9, and contains a polyalkylene oxide with a significantly low degree of unsaturation, and the total degree of unsaturation calculated from the raw materials used was 0.0031 meq/ Although the monool component that can cap the terminals of the composition is significantly less, it does not contain a urethane prepolymer component, so it does not contain a urethane prepolymer component containing urethane groups, and the number average molecular weight of the composition is as low as less than 8,000. During the coating and curing reactions, the liquid flowed violently, making it difficult to form a cured urethane product with a good coating film appearance.

(Production Example 30, Comparative Example 11)
Production Example 30 is the conventional design of Synthesis Example 14, using a solvent and using a combination of a difunctional polyalkylene oxide (AC2) with a relatively high molecular weight of 29,000 and a trifunctional polyalkylene oxide with a number average molecular weight of 7. It is designed to be a prepolymer with a molecular weight of over 1,000,000, which increases cohesive force, and the degree of unsaturation is significantly low.It is a design that can be expected to have good stain resistance due to its high molecular weight, and has a wide molecular weight distribution of over 5.5. In addition, they are a urethane prepolymer composition (GC11) containing a urethane prepolymer (EC5) with a low nonvolatile content concentration, and a urethane-forming composition (HC11).

Comparative Example 9 using the urethane-forming composition (HC11) is shown in Table 9, and both the urethane prepolymer (EC5) and the polyalkylene oxide (B1) have a significantly low degree of unsaturation, and exhibit good curability. However, since the nonvolatile content of the urethane prepolymer composition (GC11) was less than 80% and the viscosity at 25°C was less than 0.1 Pa·s, The liquid flowed easily, making it difficult to mold with high thickness. In addition, the urethane prepolymer composition (GC11) was concentrated to have a nonvolatile content concentration of 80%, but since the number average molecular weight of the urethane prepolymer composition (GC11) exceeded 70,000, the viscosity at 25°C was 30 Pa・s. The thixotropy index was similarly high, exceeding 1.5, so the design was poor in moldability, and it was difficult to maintain good handling properties and achieve high solidification.

(Production Example 31, Comparative Example 12)
In Production Example 31, the first stage NCO-terminated urethane prepolymer was prepared by using a relatively high molecular weight polyalkylene oxide (A1) with a significantly low degree of unsaturation and a polyisocyanate (C2) with an NCO/OH ratio of 2.7. This is a production example obtained by a two-stage polymerization method in which a large amount of low-molecular-weight polyalkylene oxide (AC2) with a molecular weight of 400 and a large amount of hydroxyl groups is added in the second stage after formation. A urethane prepolymer composition (GC12) that does not contain B1) but has a cohesive force by significantly increasing the amount of urethane groups using a low molecular weight polyalkylene oxide (AC2) with a molecular weight of 400, and a urethane-forming composition (HC12). ).

Comparative Example 12 using the urethane-forming composition (HC12) is shown in Table 9, and contains a urethane prepolymer (EC6) consisting of polyalkylene oxide with a significantly low degree of unsaturation, and has a high degree of unsaturation calculated from the raw materials used. The concentration was 0.0055 meq/g, which was a significantly low amount of monool component capable of capping the terminals, and the nonvolatile content was 99.7% by weight, which was significantly high, and the curability was good, but the reactivity was It contains a large amount of low molecular weight polyalkylene oxide (AC2) components, and has a rather short pot life of less than 24 hours, so it is thought that increasing the amount of volatile acetylacetone or diluting with a plasticizer, etc. is necessary to improve it. It was something.

The resulting cured urethane product (IC12) also did not contain polyalkylene oxide (B1) having three or more hydroxyl groups and contained a large amount of low molecular weight polyalkylene oxide (AC2), so the residual adhesion rate was slightly lower. Although the unsaturation degree of the entire urethane prepolymer composition (GC9) was less than 0.020 meq/g, re-peelability was possible. Due to the large number of groups, it has poor flexibility, and its glass transition point exceeds -24°C and -30°C, so it does not exhibit significantly better cold resistance than Example 1, and is used in applications that require such characteristics. was difficult.

As shown in the examples above, the urethane prepolymer composition (G) in this development uses a polyalkylene oxide that has a certain viscosity, can be highly solidified, and has less unsaturated monool, This is a urethane prepolymer composition (G) in which the urethane cured product has high cohesive strength, good stain resistance and removability, and contributes to the development of significantly good flexibility and cold resistance. It has been shown that it can be suitably used in a wide range of applications such as sealants, paints, pressure-sensitive adhesives, and adhesives due to its characteristics such as good flexibility and low-temperature properties, and the ability to follow changes in the shape of adherends.

Among these, the urethane sheet using the cured urethane product (I) of the present invention is suitable as a urethane adhesive because it has appropriate adhesive strength and exhibits removability, flexibility, cold resistance, and good tackiness. In addition, it is highly transparent, exhibits cohesive strength, remarkable flexibility, and cold resistance, making it suitable for use in bending and deformation, printing step tracking, low-temperature environments, and repeelability. It has been shown that it can be used suitably as an optical adhesive for foldable materials and as a biological adhesive.

Claims (14)

A urethane prepolymer composition (G) containing a hydroxyl group-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,
The polyalkylene oxide (B) contains a polyalkylene oxide (B1) having three or more hydroxyl groups,
The degree of unsaturation of the urethane prepolymer composition (G) is less than 0.020 meq/g, the number average molecular weight calculated by gel permeation chromatography method is less than 70,000, and the polyalkylene oxide ( A urethane prepolymer composition (G) in which the content of B) is in the range of 1 to 79% by weight. The urethane prepolymer composition (G) according to claim 1, wherein the urethane prepolymer (E) has a molecular weight distribution calculated by gel permeation chromatography of less than 1.50. The urethane prepolymer composition (G) according to claim 1, wherein the polyalkylene oxide (B) has a molecular weight calculated from a hydroxyl value of 700 to 30,000. 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. The urethane prepolymer composition (G) according to claim 1, wherein the nonvolatile 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. In the urethane prepolymer (E), alkylene oxide residues are contained in a range of 90 to 99.9% by weight, polyisocyanate residues are contained in a range of 0.1 to 10% by weight, and unsaturated groups are contained in a range of 0.03% by weight. The urethane prepolymer composition (G) according to claim 1, comprising the following range. The polyol forming the urethane prepolymer (E) contains a bifunctional polyalkylene oxide (A) with an unsaturation degree 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. , the urethane prepolymer composition (G) according to claim 1. The urethane prepolymer composition (G) according to claim 1, wherein the average functional group number fave of all polyols forming the urethane prepolymer (E) is in the range of 1.85 to 2.20. The urethane prepolymer composition (G) according to claim 7, wherein the polyalkylene oxide (A) forming the urethane prepolymer (E) contains a primary hydroxyl group. The polyisocyanate (C) contains an aliphatic isocyanate, an alicyclic isocyanate, or a modified product thereof, and the average number of functional groups fave of all the polyisocyanates forming the urethane prepolymer (E) is 1.90 to 2. 79. The urethane prepolymer composition (G) according to claim 1, wherein the composition is in the range of 79. The urethane prepolymer composition (G) according to claim 1, which contains the ketoenol tautomer compound (D) in a range of 0.01 to 1.0% by weight. A urethane-forming composition (H) comprising the urethane prepolymer composition (G) according to any one of claims 1 to 11 and an isocyanate compound (F). A cured urethane product (I) comprising a reactant of the urethane-forming composition (H) according to claim 12. A urethane adhesive comprising the cured urethane product (I) according to claim 13.