WO2022224819A1

WO2022224819A1 - Urethane prepolymer and cured urethane obtained therefrom

Info

Publication number: WO2022224819A1
Application number: PCT/JP2022/017117
Authority: WO
Inventors: 清水義久; 山本敏秀
Original assignee: 東ソー株式会社
Priority date: 2021-04-22
Filing date: 2022-04-05
Publication date: 2022-10-27
Also published as: JP2022166968A

Abstract

Provided are: a highly transparent urethane prepolymer having excellent curability and contributing to formation of polyurethanes having high strength; and a cured urethane which is highly transparent and has high strength and little surface tack.　The urethane prepolymer is a urethane prepolymer (E) terminated by an active-hydrogen group, the urethane polymer (E) having a C3 or higher, alkylene oxide residue, an aromatic amine residue, and a polyisocyanate residue and a polyol structure locally having an aromatic amine residue at a molecular end.

Description

Urethane prepolymer and urethane cured product using the same

The present disclosure relates to urethane prepolymers.

A polyalkylene oxide containing a large amount of a by-product monool having an unsaturated group at one end (hereinafter referred to as an unsaturated monool) is used as a raw material for polyurethane. However, when an attempt is made to obtain a polyurethane using this polyalkylene oxide, there arises a problem that the curing (solidification) associated with the reaction with the isocyanate compound takes a long time, impairing the productivity.

Furthermore, the polyurethane obtained from the polyalkylene oxide containing a large amount of unsaturated monool is difficult to have a high molecular weight, has a low tensile elongation at break, and a low tensile strength at break. On the other hand, even a polyalkylene oxide containing a large amount of unsaturated monool can be reacted with an isocyanate compound having a large average number of isocyanate functional groups to obtain a high molecular weight polyurethane. However, in this case, the polyurethane does not have a linearly high molecular weight, but becomes a crosslinked body having a densely crosslinked structure, so that the obtained polyurethane has a low tensile elongation at break and a low tensile strength at break.

On the other hand, since unsaturated monools have relatively low molecular weights, compositions containing conventional polyalkylene oxides containing large amounts of unsaturated monools have low viscosities, and coating machines are used to obtain polyurethanes from these compositions. etc., there is an advantage that it is easy to apply.

Here, Patent Document 1 discloses a urethane-forming composition containing a polyalkylene oxide having less unsaturated monools, a polyalkylene oxide having an aromatic amine residue, a polyalkylene oxide having one hydroxyl group and an ethylene oxide residue, and It discloses that a polyurethane having good coatability and productivity and high tensile strength can be obtained by using a urethane-forming composition containing a urethane prepolymer using the same.

However, these polyurethane-forming compositions described in Patent Document 1 and urethane prepolymers using the same contain as an essential component a polyalkylene oxide containing a small amount of low-molecular-weight unsaturated monools that tend to act as a compatibilizer, and a catalyst. Since active and rigid aromatic amine polyols are used, transparency tends to deteriorate depending on reaction conditions such as stirring conditions, reactor, and solvent amount due to poor compatibility with polyalkylene oxides, which have particularly low unsaturated monools. In addition, particulate deposits and gel-like substances may adhere, and the obtained urethane cured product may become hard and difficult to wet, resulting in poor handleability.

Therefore, the urethane prepolymer has good coatability and productivity regardless of the use of polyalkylene oxide with less unsaturated monools, and contributes to the formation of a highly transparent polyurethane containing a rigid aromatic amine polyol structure and having high strength. It is a urethane prepolymer that stably has no precipitates or gels regardless of conditions such as the amount of solvent and has good curability and transparency, and a highly transparent, high-strength urethane prepolymer obtained using it. Polyurethane with less tack was desired.

Japanese Patent Application Laid-Open No. 2020-158551

Provide a highly transparent urethane prepolymer that contributes to the formation of polyurethane with excellent curability and high strength, and a cured urethane product that is highly transparent, has high strength, and has little surface tack.

Each aspect of the present invention is [1] to [11] shown below.
[1] Active hydrogen having a polyalkylene oxide structure having an alkylene oxide residue having 3 or more carbon atoms, an aromatic amine residue and a polyisocyanate residue, and having an aromatic amine residue locally at the molecular end A terminal urethane prepolymer (E).
[2] NCO-terminated prepolymer (D) which is a reaction product of polyalkylene oxide (A) and polyisocyanate (C), and polyalkylene oxide (B) having an aromatic amine residue and two or more hydroxyl groups The urethane prepolymer (E) according to [1], which is a reactant.
[3] The urethane prepolymer (E) according to [1] or [2], containing 5 to 70% by weight of a polyalkylene oxide structure having an aromatic amine residue or a residue thereof.
[4] as aromatic amine residues, one or more residues selected from the group consisting of 4,4′-diphenylmethanediamine residues, 2,4-tolylenediamine residues and 2,6-tolylenediamine residues; The urethane prepolymer (E) according to any one of [1] to [3], containing a group.
[5] The polyisocyanate residue includes an aliphatic isocyanate residue, an alicyclic isocyanate residue, a modified residue thereof, or two or more of these residues [1] to [ 4], the urethane prepolymer (E) according to any one of the above.
[6] One or more residues selected from the group consisting of polypropylene oxide residues, polypropylene/ethylene oxide residues and polyethylene oxide residues as the polyalkylene oxide structure having an aromatic amine residue localized at the molecular end. The urethane prepolymer (E) according to any one of [1] to [5], containing a group.
[7] A urethane prepolymer composition solution containing the urethane prepolymer (E) according to any one of [1] to [6], an organic solvent and an additive,
A urethane prepolymer composition solution, wherein the urethane prepolymer concentration in the urethane prepolymer composition solution is 60% by weight or more and 99% by weight or less.
[8] A urethane-forming composition comprising the urethane prepolymer (E) according to any one of [1] to [6] and an isocyanate compound (F).
[9] A urethane-forming composition solution containing the urethane prepolymer composition solution described in [7] and an isocyanate compound (F).
[10] A cured urethane product containing the urethane-forming composition according to [8] or a reaction product of the urethane-forming composition in the urethane-forming composition solution according to [9].
[11] A polyurethane sheet made of the cured urethane product of [10].

The urethane prepolymer, which is one aspect of the present invention, is a rigid aromatic amine polyol necessary to develop high strength regardless of the presence or absence of the use of polyalkylene oxide with less unsaturated monools, reaction conditions, solvent amount, etc. Provide a urethane prepolymer that has excellent storage stability without deposits or gels even when used, and has good compatibility, transparency, and curability, and a highly transparent and high-strength urethane cured product using the same. can do.

Exemplary embodiments for carrying out the present invention are described in detail below.

A urethane prepolymer according to one aspect of the present invention has an alkylene oxide residue having 3 or more carbon atoms, an aromatic amine residue and a polyisocyanate residue, and has an aromatic amine residue locally at the end of the molecule. It is an active hydrogen group-terminated urethane prepolymer (E) having a polyol structure.
<Urethane prepolymer (E)>
The urethane prepolymer (E), which is one aspect of the present invention, has an alkylene oxide residue having 3 or more carbon atoms, an aromatic amine residue and a polyisocyanate residue, and localized aromatic amine residues at the molecular ends. It is an active hydrogen group-terminated urethane prepolymer having a polyalkylene oxide structure having a group.

The urethane prepolymer (E) contains an alkylene oxide residue having 3 or more carbon atoms as an essential component. When the alkylene oxide residue having 3 or more carbon atoms is not contained, the strength of the resulting urethane cured product tends to be increased, but the flexibility is significantly deteriorated, and the storage stability and handling properties are deteriorated, making it difficult to use. When the alkylene oxide residue containing only alkylene oxide residues having 2 carbon atoms and not containing alkylene oxide residues having 3 or more carbon atoms is used, the crystallinity is increased, and the transparency of the urethane prepolymer (E) and the obtained urethane cured product is deteriorated. The storage stability and handleability of the urethane prepolymer (E) deteriorate, making it difficult to use.

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 and the like. Among these alkylene oxide residues, polyalkylene oxide as a raw material is easily available, and it is easy to produce a liquid urethane prepolymer (E) with low crystallinity and moderate viscosity, and has high industrial value. Oxide residues are preferred.

In addition, the alkylene oxide residue having 3 or more carbon atoms may contain only a single alkylene oxide residue, or may contain two or more types of alkylene oxide residues. When two or more kinds of alkylene oxide residues are included, for example, one kind of alkylene oxide residue is linked in a chain, and another alkylene oxide residue is linked in a chain. or two or more alkylene oxide residues randomly linked together. Furthermore, it is sufficient that it contains an alkylene oxide residue with 3 or more carbon atoms, and in addition, it may contain an ethylene oxide residue with 2 carbon atoms. When it contains an ethylene oxide residue with 2 carbon atoms, its content is not particularly limited, but since the fluidity of the liquid is likely to be excellent and high coatability is likely to be expressed, the alkylene oxide residue with 3 or more carbon atoms and carbon The weight ratio of the ethylene oxide residue of number 2 (alkylene oxide residue having 3 or more carbon atoms/ethylene oxide residue having 2 carbon atoms) is preferably in the range of 10/90 to 99.9/0.1, more preferably is in the range 30/70 to 99.7/0.3, most preferably in the range 50/50 to 99.5/0.5. If it contains an ethylene oxide residue with 2 carbon atoms, it is not particularly limited, but it has a chain structure of ethylene oxide residues with 2 carbon atoms such as polyoxyethylene glycol monoalkyl ether residues because it tends to improve coatability. preferably.

The content of the alkylene oxide residue having 3 or more carbon atoms contained in the urethane prepolymer (E) is not particularly limited, but it is 30% by weight or more and 99% by weight because it tends to exhibit good coatability and high transparency. It is preferably below, more preferably in the range of 50% by weight or more and 95% by weight or less, most preferably in the range of 70% by weight or more and 90% by weight or less because it is easy to achieve both higher transparency and high strength. is. The content can be calculated by the NMR method or the analysis by Corish decomposition, but if the raw material is known, it may be calculated from the addition amount.

The urethane prepolymer (E) contains an aromatic amine residue as an essential component. When the aromatic amine residue is not contained, the transparency of the urethane prepolymer (E) and the obtained urethane cured product tends to be improved, but the strength of the urethane cured product is insufficient, and the strength such as easy peelability and durability is affected. It is difficult to use because the physical properties are significantly deteriorated, and the curability of the urethane prepolymer is insufficient, resulting in poor productivity and difficulty in use. That is, by having an aromatic amine residue having a rigid skeleton and moderate catalytic activity, the curability of the urethane prepolymer and the strength of the resulting urethane cured product are improved.

Among them, the urethane prepolymer (E) is characterized by having a polyalkylene oxide structure (hereinafter referred to as an aromatic amine polyol structure) having an aromatic amine residue locally at the molecular end. Localization in this specification refers to ``being in a certain limited place. It suffices that the polyol structure is contained excessively from the inside of the molecule so as to be biased, and it may also be contained inside the molecule.

Although it is not particularly limited as long as the aromatic amine polyol structure is locally contained around the molecular end, preferably, the aromatic amine polyol structure in the molecular end relative to the content of the aromatic amine polyol structure in the whole is high, that is, the molar ratio of the aromatic amine polyol structure at the molecular end is high with respect to the molar ratio of the aromatic amine polyol structure in the entire polyol constituting the urethane prepolymer (E). is preferred.

Aromatic amine residues generally have catalytic activity for urethanization and often have a structure similar to that of a cross-linking agent. Because of deterioration of compatibility and reactivity of urethane, stable formation of highly transparent and high strength urethane cured product regardless of the use of polyalkylene oxide with less unsaturated monol, reaction conditions, solvent amount, etc. It is difficult to Further, depending on the reaction conditions, the urethane prepolymer (E) may deteriorate in transparency or generate particulate precipitates or gels, and the obtained urethane cured product also deteriorates in transparency, making it difficult to use. That is, by including an excess polyol structure having an aromatic amine residue at the molecular end, compatibility and curability are improved, highly transparent and excellent curability urethane prepolymer (E), and obtained using it The urethane cured product stably becomes highly transparent and has high strength.

The content ratio of the aromatic amine polyol structure at the molecular end to the content of the aromatic amine polyol structure in the entire polyol (molar ratio of the aromatic amine polyol at the molecular end/molar ratio of the aromatic amine polyol in the entire polyol) is Although it is preferable if it exceeds 1.0, it is not particularly limited. Among them, it is preferably more than 1.01 and less than 10, more preferably more than 1.03 and less than 2.5, because it is likely to exhibit remarkably high transparency regardless of the reaction conditions, solid content, etc. Most preferably, it is more than 1.10 and less than 1.7.

The urethane prepolymer (E) is obtained by adding an aromatic amine polyol to the terminal. The proportion of groups may decrease according to the amount added. For example, 90 mol% of a polyol having an aromatic amine residue and 10 mol% of another polyol having no aromatic amine residue are added to the end in combination, and if there is no difference in reactivity, approximately at the molecular end The proportion of aromatic amine polyol structures contained is 90%. Monools often seal the ends of molecules regardless of the timing of the reaction, but since they do not have reactive hydroxyl groups after the reaction, they are not included in the polyol structural residues at the ends of the molecules.

The ratio of the aromatic amine polyol structure contained at the molecular terminal is not particularly limited, but if the ratio of the aromatic amine polyol structure contained at the molecular terminal decreases, compatibility with the cross-linking agent may deteriorate and reactivity may decrease. It is easy to form a highly transparent and strong urethane cured product regardless of the use of polyalkylene oxide with low unsaturated monools, reaction conditions, solvent amount, etc., so the aromatic amine polyol structure ratio at the molecular end is It is preferably 30% or more. Among them, it is preferable that the aromatic amine polyol structure ratio at the molecular terminal is 60% or more, more preferably the urethane prepolymer (E) contains 20% by weight or more of the aromatic amine polyol structure, and The structural ratio of the aromatic amine polyol is 80% or more and 100% or less, and most preferably, the structural ratio of the aromatic amine polyol at the molecular terminal is 90% or more and 99.99% or less.

In addition, for example, polyols having a molecular weight of less than 2000 and having aromatic amine residues usually exhibit significantly higher reactivity than polyols having a molecular weight of more than 2000 and not having aromatic amine residues. Although it varies somewhat depending on the method, when a polyol having a molecular weight of more than 2000 and a polyol having a molecular weight of less than 2000 having an aromatic amine residue are used in the same molar ratio (1:1) by a conventional method, the molecular The aromatic amine polyol structure ratio at the terminal is less than 50%, and a polyol having a molecular weight of more than 2000 containing no aromatic amine residue and a polyol having a molecular weight of less than 2000 having an aromatic amine residue were used at a molar ratio of 1:9. In this case, the aromatic amine polyol structure ratio at the molecular end is less than 90%. Therefore, the content ratio of the aromatic amine polyol structure at the molecular end is lower than the content ratio of the aromatic amine polyol structure as a whole.

The polyol structural ratio at the end of the molecule may be obtained from the analysis of the primary ratio of terminal hydroxyl groups, the analysis of residues such as alkylene oxides adjacent to hydroxyl groups, and the analysis of various decomposition products. In addition, after forming an isocyanate-terminated prepolymer, when adding only a polyol having an aromatic amine residue at the terminal until the NCO group disappears, theoretically almost all the molecular terminals are aromatic amine polyol structures, and the molecular terminals was determined to have an aromatic amine polyol structure ratio of 100%.

When a polyol having an aromatic amine residue and another polyol not having an aromatic amine residue are used in combination and added to the terminal, when the terminal has the same alkylene oxide residue with a molecular weight of at least the same level, usually, Polyols with aromatic amine residues have higher reactivity, and the structural ratio of the terminals correlates with the ratio of combined use. Calculated, when 90 mol% of a polyol having an aromatic amine residue and 10 mol% of another polyol having no aromatic amine residue are used in combination to add to the end, the aromatic amine polyol structural ratio at the molecular end is 90. % or more.

The aromatic amine polyol structure having a molecular terminal is not particularly limited, but since it is more compatible and tends to be highly transparent, the polyalkylene oxide residue includes a polypropylene oxide residue, a polypropylene oxide/polyethylene oxide residue, and a polyethylene oxide residue. More preferably, it contains one or more types of residues selected from the group consisting of residues, and includes any of block structures, random structures, gradient structures, and the like. Among them, it is preferable to have a propylene oxide residue as an alkylene oxide residue, and most preferably 40% by weight or more of the alkylene oxide residue is propylene oxide because it is difficult to crystallize from low temperature to high temperature and is particularly easy to have excellent fluidity. A residue is preferred. The content can be calculated by the NMR method or the analysis by Corish decomposition, but if the raw material is known, it may be calculated from the structure of the raw material.

The structure of the aromatic amine residue contained in the urethane prepolymer (E) is not particularly limited. It is an aromatic amine residue having 1 or more and 3 or less rings.

Although the content of the aromatic amine residue contained in the urethane prepolymer (E) is not particularly limited, it is preferably 0.5% by weight or more and 25% by weight or less, more preferably more than 0.5% by weight, in order to easily develop high strength. It is in the range of 1% by weight or more and 15% by weight or less, and most preferably in the range of 3% by weight or more and 10% by weight or less, because it is easy to achieve both high strength and handleability of the cured product. The content can be calculated by the NMR method or analysis by Corish decomposition, but if the raw material is known, it may be calculated from the molecular weight of the polyalkylene oxide calculated from the hydroxyl value, the nominal initiator structure, and the amount added.

Examples of such aromatic amine residues include aniline residues, 2,4-tolylenediamine residues, 2,6-tolylenediamine residues, 2,2′-diphenylmethanediamine residues, 2,4 '-diphenylmethanediamine residue, 4,4'-diphenylmethanediamine residue, polyphenylenepolyamine residue, 1,5-naphthalenediamine residue, tolidinediamine residue, xylylenediamine residue, 1,3-phenylenediamine residue , 1,4-phenylenediamine residues, and residues of two or more of these, preferably 2,4-triamine, which is easy to obtain raw materials and tends to exhibit good curability and high strength. diamine residues, 2,6-tolylene diamine residues, and two or more of these residues. The structure of aromatic amine residues can be analyzed by MALDI-TOF-MS or the like.

The aromatic amine residue contained in the urethane prepolymer (E) is usually obtained by adding an aromatic amine or an aromatic amine polyol to the terminal or inside the molecule, but it tends to have excellent compatibility and high transparency. Therefore, it preferably contains a polyol structure having an aromatic amine residue or a residue thereof. The content of the polyol structure having an aromatic amine residue or the residue thereof is preferably 5 to 70% by weight, more preferably 5 to 70% by weight, because it tends to exhibit remarkably high strength and easily improve coatability. is in the range of 10-55% by weight, most preferably in the range of 20-50% by weight. The polyol structure having an aromatic amine residue or the content of the residue thereof can be calculated by analysis using alkali decomposition, Kolish decomposition, or the like, but if the raw material is known, it may be calculated from the added amount.

The urethane prepolymer (E) contains a polyisocyanate residue as an essential component. If the urethane prepolymer (E) does not contain a polyisocyanate residue, the urethane prepolymer (E) does not contain any urethane groups with cohesive strength and curability is lowered, making it difficult to use. The wettability to the surface is lowered, making it difficult to use. Moreover, it is difficult to form a polyol structure selectively having an aromatic amine residue at the terminal.

The polyisocyanate residue contained in the urethane prepolymer (E) is not particularly limited as long as the average number of functional groups of the isocyanate residue is 2.0 or more.

The structure of the polyisocyanate residue is not particularly limited. 4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate , tetramethylxylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate , 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, and modifications obtained by reacting these with polyalkylene oxide Isocyanates, as well as residues of mixtures of two or more of these, are included. Furthermore, these isocyanates contain modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups, uretdione groups or oxazolidone groups, and polymethylene polyphenylene polyisocyanates. Condensate residues such as (polymeric MDI) can be mentioned.

Among these, aliphatic isocyanate residues, alicyclic isocyanate residues and modified residues thereof are used as polyisocyanate residues in order to easily obtain a urethane-forming composition with excellent productivity and high transparency and little coloration. It preferably contains one or more residues selected from the group consisting of

The residue of such a polyisocyanate (C) is not particularly limited. isocyanate-containing prepolymers, alicyclic isocyanate-containing prepolymers, or urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups of these isocyanates, Modified residues containing uretdione groups or oxazolidone groups are more preferred. These isocyanate residues may contain one type alone, or two or more types of residues.

Above all, it is preferable to contain 1,6-hexamethylene diisocyanate and residues of modified products thereof because the increase in viscosity of the urethane prepolymer with time is small and the storage stability is excellent. In addition, having a primary NCO group and a secondary NCO group with different reactivity, it is easy to suppress the increase in molecular weight due to chain reaction, and it is easy to suppress the deterioration of coating properties and the increase in viscosity. It is also preferable to contain a residue of isophorone diisocyanate because the transparency of the urethane cured product obtained using is likely to be remarkably improved. Therefore, it preferably contains at least one residue selected from 1,6-hexamethylene diisocyanate, modified products thereof, and isophorone diisocyanate.

Although the content of the polyisocyanate residue contained in the urethane prepolymer (E) is not particularly limited, it is preferably 0.5% by weight or more and 30% by weight or less, more preferably higher, because high strength is likely to be expressed. Since it is easy to achieve both transparency and high strength, it is in the range of 2% by weight or more and 20% by weight or less, and most preferably in the range of 4% by weight or more and 12% by weight or less.

The content can be calculated by the NMR method or analysis by Corish decomposition, but if the raw material is known, it may be calculated from the added amount.

The urethane prepolymer (E) contains, as essential components, an alkylene oxide residue having 3 or more carbon atoms, an aromatic amine residue, a polyisocyanate residue, and the exemplified ethylene oxide residue having 2 carbon atoms, as well as other It may contain residues. Examples include, but are not limited to, carbonate residues, oxytetramethylene residues, sugar residues, ester residues, oxetane residues, caprolactone residues, isobutylene residues, butadiene residues, alkyl ether residues, Mannich polyol residues. , an acrylic residue, a silicone residue, a fluorine residue, a phosphate residue, an aliphatic amine residue, an imine residue, a quaternary ammonium residue, an isocyanurate residue, etc., and can be suitably included. . Among them, the urethane prepolymer (E) expresses higher curability and coatability, making it easier to obtain a high-strength urethane cured product. It preferably contains residues, carbonate residues, aliphatic amine residues. The content of the exemplified residue is not particularly limited, but it is preferably in the range of 0.01% to 70% by weight, more preferably in the range of 0.01% by weight to 70% by weight because it is easy to achieve both high curability and coatability. is in the range of 0.1% to 50% by weight, most preferably in the range of 0.5% to 20% by weight.

In addition, the urethane prepolymer (E) may contain a monool structure having an unsaturated group in the polyalkylene oxide used, and may contain an unsaturated group which is the residue thereof.

The urethane prepolymer (E) is not particularly limited because it exhibits high curability regardless of the use or non-use of polyalkylene oxide with a small amount of unsaturated monools. The unsaturated group content is preferably in the range of 0.0001 meq/g to 100 meq/g. If it does not have a highly reactive unsaturated group such as a urethane acrylate group or a urethane methacrylate group that can substantially act as a reactive group, it tends to exhibit higher curability. 0003 meq/g to 0.050 meq/g, more preferably 0.0005 meq/g to 0.010 meq/g, most preferably 0.0007 meq/g to 0.002 meq/g is in the range of The content of unsaturated groups can be analyzed by various analytical methods such as NMR.

The ratio of primary hydroxyl groups in the urethane prepolymer (E) is not particularly limited as it varies depending on the ratio of primary hydroxyl groups in each raw material polyol. . The ratio of primary hydroxyl groups in the urethane prepolymer (E) can be calculated from the peak shift of 1H NMR by reacting trifluoroacetic anhydride with hydroxyl groups using trifluoroacetic anhydride, similar to the calculation of the ratio of primary hydroxyl groups in polyalkylene oxide. There is a method of reacting phthalic anhydride with a hydroxyl group and calculating from the peak shift of 1H NMR, and in the present invention, the approximate ratio was calculated by applying the above method.

In the urethane prepolymer (E), the residual amount of the aromatic amine polyol and the polyol itself used in combination is preferably small, and is not particularly limited, but is within 20% by weight because remarkably high transparency tends to be exhibited. More preferably, it is in the range of 10% by weight or less. Among them, the residual amount of polyalkylene oxide having no aromatic amine polyol residue is preferably in the range of 5% by weight or less, more preferably in the range of 2% by weight or less, because it tends to achieve higher transparency. is. The residual amount of the aromatic amine polyol and the polyol used in combination in the urethane prepolymer (E) may be determined by a peak integration ratio (aromatic amine polyol and polyol used in combination/main peak×100) such as by GPC method.

The urethane prepolymer (E) is not particularly limited. Such a urethane prepolymer (E) can be produced efficiently and easily.

Among them, the preferred properties are that additives can be easily mixed in the post-process, the handling of the cross-linking agent and coating is excellent, and the urethane cured product tends to be stably highly transparent. Therefore, the viscosity is in the range of 3 to 50 Pa·s, more preferably in the range of 5 to 30 Pa·s. When the viscosity is high, a solvent or additive may be added to reduce the viscosity, and when the viscosity is low, the viscosity may be increased by concentration or the like.

The transparency of the urethane prepolymer (E) is not particularly limited. % or less.

The molecular weight of the urethane prepolymer (E) is not particularly limited, but the weight average molecular weight measured by gel permeation chromatography is preferably in the range of 2500 or more and 500000 or less, since the handleability tends to be better, and 5000 It is more preferably in the range of 200,000 or more, and more preferably in the range of 10,000 or more and 100,000 or less.

The active hydrogen group-terminated urethane prepolymer (E) is characterized by containing a polyol structure having an aromatic amine residue locally around the molecular end. The production method is not particularly limited as long as it can be introduced excessively. For example, although not particularly limited, a method of adding a polyol having an aromatic amine residue at the end or end of the process to add it to the end, a polyol having an aromatic amine residue by adjusting the reactivity of the raw material used is added at the end or end to introduce it at the end, which can be suitably applied.

Examples of adjusting the reactivity of the raw material used include reducing the reactivity of polyols having aromatic amine residues and/or improving the reactivity of polyols used in combination, and forming block structures by protecting reactive groups. For example, reducing the reactivity of a polyol having an aromatic amine residue with a solid content of 70% or more includes increasing the molecular weight of the polyol having an aromatic amine residue (for example, 500 or more) or increasing the number of secondary hydroxyl groups. Introduction, addition of an acid compound, and improvement of the reactivity of the polyol used in combination include lowering the molecular weight of the polyol used in combination (for example, 6000 or less), ethylene oxide residue, tetrahydrofuran residue, and propylene oxide residue having a primary hydroxyl group at the end. (for example, ethylene oxide residue 16% by weight or more, primary conversion rate 75% or more), etc., but the structure of the polyol used in combination and the structure of the aromatic amine polyol , the reactivity of each material differs depending on the solid content, etc., and the terminal structure ratio changes, so there is no particular limitation.

The most preferred method for producing the active hydrogen group-terminated urethane prepolymer (E) is not particularly limited. By adding a polyalkylene oxide having a hydroxyl group as described above, a polyol structure having an aromatic amine residue at the end can be stably formed regardless of the reactivity of the raw material, and significantly regardless of the reaction conditions. It is preferable because it stably exhibits high transparency. That is, an NCO-terminated urethane prepolymer (D) which is a reaction product of at least a polyalkylene oxide (A) and a polyisocyanate (C), and a polyalkylene oxide (B) having an aromatic amine residue and two or more hydroxyl groups. is preferably a reactant of
<Polyalkylene oxide (A)>
The number average molecular weight of the polyalkylene oxide (A), which is preferably used for the urethane prepolymer (E) and the NCO-terminated urethane prepolymer (D), is not particularly limited. In addition, it is preferably 2,000 or more because the coatability and wettability tend to be good. Among them, the polyalkylene oxide (A) preferably has a number average molecular weight of 2,500 or more and less than 30,000, more preferably 3,000 or more and less than 13,000, and most preferably 3,500 or more and less than 9,000. The number average molecular weight of the polyalkylene oxide (A) is 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). , can be calculated from The hydroxyl value (mgKOH/g) of the polyalkylene oxide (A) is not particularly limited, but is preferably 3 or more and 250 or less, more preferably 5 or more and 180 or less, and most preferably 8 or more and 70 or less. .

The viscosity of the polyalkylene oxide (A) at 25° C. is not particularly limited and is appropriately selected depending on the application, but is preferably 100 mPa·s or more and 200000 mPa·s or less, more preferably 200 mPa·s or more and 10000 mPa·s or less. is. If the viscosity of the polyalkylene oxide (A) at 25° C. is 100 mPa·s or more and 200000 mPa·s or less, it is preferable because it is easy to apply with a coating machine or the like to obtain a polyurethane product. Here, the "viscosity" at 25°C is measured at a shear rate of 0.1 (1/s) using a cone/plate rotational viscometer in accordance with JIS K1557-5 Section 6.2.3. value.

The polyalkylene oxide (A) preferably contains an alkylene oxide residue having 3 or more carbon atoms because it has excellent fluidity from low to high temperatures. 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 and the like. Among these alkylene oxide residues, a propylene oxide residue is preferred because the starting material for obtaining the polyalkylene oxide (A) is readily available and the resulting polyalkylene oxide (A) has a high industrial value.

Further, 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. When two or more kinds of alkylene oxide residues are included, for example, one kind of alkylene oxide residue is linked in a chain, and another alkylene oxide residue is linked in a chain. or two or more alkylene oxide residues randomly linked together. Furthermore, the polyalkylene oxide (A) may contain an ethylene oxide residue with 2 carbon atoms in addition to the alkylene oxide residue with 3 or more carbon atoms.

In addition, the number of hydroxyl groups in the polyalkylene oxide (A) is not particularly limited, but it preferably has two or more hydroxyl groups in one molecule, more preferably two or more and six or less, and most preferably one. The number of hydroxyl groups in the molecule is 2 or more and 3 or less. When the number of hydroxyl groups in one molecule of the polyalkylene oxide (A) is 6 or less, the crosslinked structure of the resulting urethane cured product is difficult to be dense, and the tensile elongation at break and strength are further increased, which is preferable.

Although the primary ratio of hydroxyl groups in the polyalkylene oxide (A) is not particularly limited, it is preferably in the range of 0 to 90%. When synthesizing with a cationic polymerization system such as trifluoroborane or trispentafluorophenylborane as a catalyst, even if propylene oxide or the like other than ethylene oxide is used as the alkylene oxide, the primary ratio tends to increase, and a basic catalyst such as potassium hydroxide is used. When using a metal-based catalyst such as a double metal cyanide (DMC) catalyst, the primary ratio tends to be low, but there are no particular limitations including the terminal structure, and any of them can be suitably used.

In addition, the polyalkylene oxide (A) is preferably liquid at room temperature because it facilitates the production of the urethane prepolymer.
The degree of unsaturation of the polyalkylene oxide (A) is not particularly limited because it is easy to make the prepolymer or urethane cured product highly transparent regardless of whether or not a polyalkylene oxide with less unsaturated monools is used. It is preferable that it is 0.010 meq / g or less, more preferably 0.010 meq / g or less because it is likely to require an increase in the amount of polyfunctional polyol such as polyalkylene oxide (B) having a bifunctional polyol having a more rigid skeleton than polypropylene oxide. It is 0.007 meq/g or less, most preferably 0.004 meq/g or less. Such polyalkylene oxide (A) having a low degree of unsaturation is not particularly limited, but can be produced by adding an alkylene oxide to an active hydrogen compound using an iminophosphazenium salt and a Lewis acid catalyst. .
The molecular weight distribution (Mw/Mn) of the polyalkylene oxide (A) is not particularly limited because it is easy to make the prepolymer or urethane cured product highly transparent regardless of whether a polyalkylene oxide having a narrow molecular weight distribution is used, but the molecular weight of the prepolymer Since the distribution tends to be narrow and the handleability tends to be excellent, it is preferably 1.059 or less, more preferably 1.039 or less, and most preferably 1.004 to 1.029 or less.
The polyalkylene oxide (A) preferably has a water content of 2,000 ppm or less.

<Polyisocyanate (C)>
The polyisocyanate (C) preferably used for the urethane prepolymer (E) and the NCO-terminated urethane prepolymer (D) preferably has an average functional group number of isocyanate groups of 2.0 or more, but is particularly limited. is not. Examples of the polyisocyanate (C) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and tolidine. Diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate , isophorone diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3,6-hexamethylenetri Examples include isocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, modified isocyanate obtained by reacting these with polyalkylene oxide, and mixtures of two or more thereof. Furthermore, these isocyanates contain modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups, uretdione groups or oxazolidone groups, and polymethylene polyphenylene polyisocyanates. Condensates such as (polymeric MDI) can be mentioned.

Among these, aliphatic isocyanate, alicyclic isocyanate, Alternatively, modified forms thereof are preferred. 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 singly or in combination of two or more.

Among them, 1,6-hexamethylene diisocyanate and modified products thereof are used because of high reactivity, good productivity, and excellent storage stability with little increase in viscosity of the urethane prepolymer (E) over time. It is preferable to use In addition, having a primary NCO group and a secondary NCO group with different reactivity, it is easy to suppress the increase in molecular weight due to chain reaction, and it is easy to be excellent in coatability and viscosity. It is also preferred to use isophorone diisocyanate, since the transparency of the product tends to be significantly better. Therefore, it is preferable to contain at least one selected from 1,6-hexamethylene diisocyanate, modified products thereof, and isophorone diisocyanate.
<Polyalkylene oxide (B)>
A polyalkylene oxide (B) preferably used in the urethane prepolymer (E) is a polyol having an aromatic amine residue. By having an aromatic amine residue in the polyalkylene oxide (B), the hardness and tensile strength of the obtained polyurethane tend to be remarkably increased. Among them, it exhibits good fluidity and is easy to mold, and it has high hardness and tensile strength and is easy to have excellent urethane physical properties. Polyols having two or more hydrogen groups are preferred, and those in which one type of alkylene oxide is linked to an aromatic amine in a chain, those in which a plurality of alkylene oxides are linked to an aromatic amine in a chain or randomly, Anything is fine.

Among them, since alkylene oxides are easily available industrially and the synthesis tends to be simple, those in which only propylene oxide is linked to an aromatic amine in a chain, those in which only ethylene oxide is linked to an aromatic amine in a chain, It is preferable that propylene oxide and ethylene oxide are linked in a chain or randomly linked to an aromatic amine, and more preferably, the propylene oxide residue is not easily crystallized from low temperature to high temperature and tends to be particularly excellent in fluidity. More preferably, 40% by weight or more of the alkylene oxide residues contained in the polyalkylene oxide (B) are propylene oxide residues.

The polyalkylene oxide (B) preferably has 2 or more hydroxyl groups per molecule, more preferably 3 or more and less than 15 hydroxyl groups, and most preferably 4 or more and less than 6 hydroxyl groups.

When the number of hydroxyl groups in one molecule of the polyalkylene oxide (B) containing an aromatic amine residue in one molecule is 3 or more and less than 15, the crosslinked structure of the resulting urethane cured product tends to be uniform, and tensile rupture occurs. It is preferable because the strength is further increased.

The number average molecular weight of polyalkylene oxide (B) is preferably less than 2,000. When the number average molecular weight is less than 2000, the content of the aromatic amine residue tends to increase, the strength tends to be further improved, and the reactivity is improved, so that a large amount of unreacted polyalkylene oxide (B) is less likely to remain, making it more stable. easily exhibit high transparency.

Among them, it is not particularly limited and is appropriately selected depending on the application. It is preferably 200 or more and less than 1,800, more preferably 400 or more and less than 1,300, and most preferably 450 or more and less than 1,000.

The number average molecular weight of the polyalkylene oxide (B) is the hydroxyl value of the polyalkylene oxide (B) calculated by the method described in JIS K-1557-1, the number of hydroxyl groups in one molecule of the polyol (A2), can be calculated from In the case of commercial products, the nominal number of functional groups and hydroxyl value can be used.

Although the structure of the aromatic amine residue of the polyalkylene oxide (B) is not particularly limited, it is preferably an aromatic amine residue having 1 or more and 20 or less aromatic rings in one molecule, more preferably an aromatic ring. It is an aromatic amine residue having a number of 1 or more and 3 or less. If the polyalkylene oxide (B) does not contain an aromatic amine residue, the tensile strength at break tends to be insufficient, and the aromatic amine itself is used to improve the strength, or a polyol containing a cyclic sugar residue having 6 or more carbon atoms. , polyester polyols, polyoxytetramethylene glycol, and other polyalkylene oxides (A) require relatively rigid polyols. and tack tends to be high.

The content of the aromatic amine residue in the polyalkylene oxide (B) is not particularly limited, but it is preferably 7% by weight or more, more preferably 7% by weight or more, because it tends to develop high strength, more preferably higher transparency and strength. Since compatibility is easily achieved, the range is 10% by weight or more and 50% by weight or less, and most preferably the range is 13% by weight or more and 30% by weight or less. The content can be calculated by the NMR method or the analysis by Corish decomposition, or it may be calculated from the molecular weight of the polyalkylene oxide calculated from the hydroxyl value and the nominal initiator structure.

Examples of such aromatic amine residues include aniline residues, 2,4-tolylenediamine residues, 2,6-tolylenediamine residues, 2,2′-diphenylmethanediamine residues, 2,4 '-diphenylmethanediamine residue, 4,4'-diphenylmethanediamine residue, polyphenylenepolyamine residue, 1,5-naphthalenediamine residue, tolidinediamine residue, xylylenediamine residue, 1,3-phenylenediamine residue , 1,4-phenylenediamine residues, and residues of two or more of these, preferably 4,4' which is easy to obtain raw materials and exhibits good curability and tensile strength at break. - is one or more residues selected from the group consisting of diphenylmethanediamine residues, 2,4-tolylenediamine residues and 2,6-tolylenediamine residues.

Polyalkylene oxide (B) is generally obtained by ring-opening polymerization of an alkylene oxide using an aromatic amine such as tolylenediamine or diphenylmethanediamine as an initiator. In some cases, a low-viscosity active hydrogen compound containing no aromatic amine residue, such as glycol, is used in combination with the initiator for synthesis, and may contain a component having the residue described above.

For example, tolylenediamine-initiated polyol usually has 4 hydroxyl groups and aniline-initiated polyol has 2 hydroxyl groups. The number of hydroxyl groups may decrease due to residual amino groups.

Examples of commercially available polyalkylene oxides (B) containing aromatic amine residues include Huntsman JEFFOLAD-310 (nominal functionality 3.2, hydroxyl value 310), JEFFOLAD-500 (nominal functionality 3.2, hydroxyl value 360 ), Toho Polyol AB-250 manufactured by Toho Chemical Industry Co., Ltd. (nominal functional group number 2.0, hydroxyl value 440), AR-2589 manufactured by Toho Chemical Industry Co., Ltd. (nominal functional group number 4.0, hydroxyl value 360), manufactured by Toho Chemical Industry Co., Ltd. AR-750 (nominal functional group number: 4.0, hydroxyl value: 300) and the like can be preferably used.

In addition to the polyalkylene oxide (B), other rigid polyols may be used in combination of two or more, and are not particularly limited. Examples thereof include a combination of a polyol containing a sugar residue with 6 or more carbon atoms and a polyol containing an aromatic amine residue.
The polyalkylene oxide (B) preferably has a water content of 2,000 ppm or less.
<Other polyols and monools>
The urethane prepolymer (E) and the NCO-terminated urethane prepolymer (D), which is preferably used, are not particularly limited. In order to improve the desired properties, adjust the NCO group ratio of the polyisocyanate (C) with respect to the total amount of active hydrogen groups of the polyol, etc., the exemplified polyalkylene oxide (A), polyalkylene oxide (B), and polyisocyanate (C) In addition, other polyols and monools (AC) may be used.

Other polyols and monools (AC) can be appropriately selected from those that do not impair the transparency and physical properties of the prepolymer, and are not particularly limited. Examples include polycarbonate polyols, polytetramethylene glycol, polyolefin polyols, acrylic Commercially available polyols such as polyols, polyester polyols, Mannich polyols, sucrose polyols, aliphatic diamine polyols, polyethylene glycols, polycaprolactone polyols, fluorinated polyols, silicone-containing polyols, phosphorus-based polyols, polyoxyalkylene glycol monoalkyl Ethers, polyoxyalkylene glycol monoalkenyl ethers, polyoxyalkylene glycol monophenyl ethers, monools such as silicone-containing monools, low molecular weight organic compounds such as cyclohexanedimethanol, tetraethylene glycol, tripropylene glycol, tripropylene glycol monobutyl ether compounds and the like.

Among them, it is selected from the group consisting of polyoxyalkylene glycol monoalkyl ethers, polyoxyalkylene glycol monoalkenyl ethers, and polyoxyalkylene glycol monophenyl ethers because of its particularly excellent coatability when applied with a coating machine or the like. Among them, it is preferable to use one or more kinds of urethanes having a molecular weight of 250 or more and 1300 or less. It is preferred to add polyoxyethylene glycol monomethyl ether.

It is preferable not to use a silicone component (monool, polyol, polyamine) having a reactive group or a fluorine component having a reactive group. This is preferable because it is easily incorporated into the molecular chain and the deterioration of the staining property is easily reduced.
<NCO-Terminated Urethane Prepolymer (D)>
The active hydrogen group-terminated urethane prepolymer (E) is not particularly limited, but it is preferable to use an NCO-terminated urethane prepolymer (D) comprising at least polyalkylene oxide (A) and polyisocyanate (C).

The NCO-terminated urethane prepolymer (D) has a ratio of NCO groups of the polyisocyanate (C) to the total amount of active hydrogen groups of the polyol containing the polyalkylene oxide (A) (NCO/OH ratio) of 1.30 to 5.00. It is preferable to mix at a quantity ratio that is the ratio of By mixing in an amount ratio that gives an NCO/OH ratio of 1.30 to 5.00, the urethane prepolymer (D) and the obtained urethane cured product have an appropriate viscosity and tend to have good handleability. transparency is easier to improve.

Among them, a high-molecular-weight substance chain-reacted in the NCO-terminated urethane prepolymer (D), mainly having a structure in which the polyalkylene oxide (A) and the polyisocyanate (C) reacted at a molar ratio of 1:2. or free (unreacted) polyisocyanate (C), and the transparency of the urethane prepolymer (E) and its urethane cured product even when using a polyalkylene oxide (B) having a polyfunctional aromatic amine residue is likely to be remarkably good, the ratio of the NCO groups of the polyisocyanate (C) to the total amount of active hydrogen groups of the polyol containing the polyalkylene oxide (A) (NCO/OH ratio) is in the range of 1.60 to 4.40. and more preferably in the range of 1.90 to 3.60.

Among them, when a polyisocyanate (C) such as hexamethylene diisocyanate or a derivative thereof having no difference in NCO group reactivity is used as the polyisocyanate (C), the NCO/OH ratio is in the range of 2.20 to 3.60. When isophorone diisocyanate is used as the polyisocyanate (C), forming the urethane prepolymer (D) with an NCO/OH ratio in the range of 2.00 to 3.10 suppresses gelation and high viscosity while maintaining transparency. It is most preferable because it tends to have good properties.

Furthermore, by using a small amount of polyalkylene oxide (B), free (unreacted) polyisocyanate (C) can be reduced, and when forming urethane prepolymer (E), polyalkylene oxide (B) and polyisocyanate It is preferable because the chain reaction of (C) can be easily suppressed, the coatability of the resulting urethane prepolymer (E) can be improved, and the cured urethane product can easily exhibit high transparency.

In addition, it is selected from the group consisting of polyoxyalkylene glycol monoalkyl ethers, polyoxyalkylene glycol monoalkenyl ethers, and polyoxyalkylene glycol monophenyl ethers for particularly excellent coatability when coated with a coating machine or the like. It is preferable to form a urethane prepolymer (D) by adding one or more of them. Among them, the urethane prepolymer (D) tends to be excellent in coatability, and while maintaining high transparency, the resulting urethane tends to have low staining resistance and low tackiness. Therefore, it is preferable to add polyoxyethylene glycol monomethyl ether having a molecular weight of 250 or more and 1300 or less.

It is preferable not to use a silicone component (monool, polyol, polyamine) having a reactive group or a fluorine component having a reactive group. This is preferable because it is easily incorporated into the molecular chain and the deterioration of the staining property is easily reduced.

When forming the urethane prepolymer (D), in addition to the polyalkylene oxide (A), when adding the polyalkylene oxide (B) and other polyols and monools (AC), if too much, the amount of hydroxyl groups in the system When the NCO/OH ratio becomes too low, it becomes difficult to form an NCO-terminated prepolymer, or gelation or thickening tends to occur, resulting in poor moldability and poor transparency of the resulting prepolymer or urethane cured product. Therefore, it is preferable to add the polyalkylene oxide (B) and other polyols and monools (AC) in a total amount of 30 parts by weight or less to 100 parts by weight of the polyalkylene oxide (A). Among them, the handling property is good, it is easy to express higher transparency, and it is easy to express higher strength. Adding in ranges is most preferred.

In addition, a urethanization catalyst, a solvent, a plasticizer, a leveling agent, and other additives may be added as necessary to form the urethane prepolymer (D). Among them, the polyalkylene oxide (A) and the polyisocyanate ( Based on the total amount of the polyol and polyisocyanate containing C), it is preferable that the urethanization catalyst containing the metal component is contained in the range of 0.001 to 0.2% by weight, and more preferably the urethanization catalyst containing the metal component is 0. 0.003 to 0.1 weight percent, most preferably 0.005 to 0.05 weight percent.

The urethanization catalyst containing a metal component is not particularly limited as long as it is a compound containing a metal component and exhibiting urethanization activity. An organometallic compound containing one or more metals selected from Fe, Sn, Zr, Ti, and Al. is preferably Among them, one of Sn catalysts that are easily available and have low temperature dependence of catalytic activity, and metal chelate catalysts such as Fe chelate catalysts, Zr chelate catalysts, Ti chelate catalysts, and Al chelate catalysts that are easy to adjust reactivity, or The use of two or more catalysts is more preferable because the NCO-terminated urethane prepolymer can be efficiently formed, and the use of the Fe chelate catalyst alone is most preferable.

Although the Sn catalyst is not particularly limited, examples thereof include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diversate, dibutyltin bis(acetylacetonate), and the like.

The Fe chelate catalyst is not particularly limited. Al chelate catalysts such as acetate include aluminum trisacetylacetonate and the like.

When the urethane prepolymer (D) is formed in advance, it is not particularly limited, but it is preferable to mix the organic solvent in an amount ratio such that the solid content concentration is in the range of 60 to 99% by weight, more preferably 70 to 97% by weight. %, most preferably in the range of 85-95% by weight.

Examples of solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, benzene, dioxane, acetonitrile, tetrahydrofuran, dimethylsulfoxide, N-methylpyrrolidone, dimethylformamide, glycol ether solvents, and the like. In addition to ease of handling such as solubility and the boiling point of organic solvents, the resulting urethane cured product tends to exhibit higher transparency. Solvents are preferred.

Among them, urethane that stays in the system during drying and curing for a long period of time to maintain compatibility and stably suppresses curing shrinkage that tends to occur during reaction curing, and has good moldability and a good appearance without wrinkles. Since it is easy to form, it is preferable to contain a glycol ether solvent with an sp value of 8.0 or more, such as diethylene glycol diethyl ether (sp value 8.2, boiling point 189 ° C.), triethylene glycol dimethyl ether (sp value 8.4, boiling point 216°C), diethylene glycol ethyl methyl ether (sp value 8.1, boiling point 176°C), diethylene glycol dimethyl ether (sp value 8.1, boiling point 162°C), tetraethylene glycol dimethyl ether (sp value 8.5, boiling point 275°C) , propylene glycol monomethyl ether acetate (sp value 8.7, boiling point 146 ° C.), ethylene glycol monomethyl ether acetate (sp value 9.0, boiling point 145 ° C.), ethylene glycol monobutyl ether acetate (sp value 8.9, boiling point 188° C.), methoxybutyl acetate (sp value 8.7, boiling point 171° C.), triacetin (sp value 10.2, boiling point 260° C.), among others diethylene glycol diethyl ether (sp value 8.2 , boiling point 189 ° C.), triethylene glycol dimethyl ether (sp value 8.4, boiling point 216 ° C.), ethylene glycol monobutyl ether acetate (sp value 8.9, boiling point 188 ° C.). preferable. Furthermore, by using ethyl acetate, toluene, and methyl ethyl ketone in combination, the moldability can be easily adjusted.

The preparation of the urethane prepolymer (D) is not particularly limited as long as it is a method capable of uniformly dispersing and reacting the raw materials. A method of stirring using a machine can be mentioned. Examples of the stirrer include a general-purpose stirrer, a rotation-revolution mixer, a disper disperser, a dissolver, a kneader, a mixer, a laboplastomill, a planetary mixer, and the like.

The molecular weight of the NCO-terminated urethane prepolymer (D) is not particularly limited, but the weight-average molecular weight measured by gel permeation chromatography is preferably in the range of 2,500 to 500,000, since the handling property tends to be better. , more preferably in the range of 5,000 to 200,000, and more preferably in the range of 10,000 to 100,000.
<Method for producing urethane prepolymer (E)>
The active hydrogen group-terminated urethane prepolymer (E), which is one aspect of the present invention, is not particularly limited, but is preferably a reaction product of an NCO-terminated urethane prepolymer (D) and a polyalkylene oxide (B). Urethane prepolymer (D) preferably comprises at least polyalkylene oxide (A) and polyisocyanate (C).

The method for producing the urethane prepolymer (E) is not particularly limited, but the total amount of NCO groups of the polyisocyanate (C) with respect to the total amount of active hydrogen groups containing the polyalkylene oxide (A) and the polyalkylene oxide (B). (NCO/OH molar ratio) of 0.10 to 0.70 to produce an active hydrogen group-terminated urethane prepolymer (E). That is, the molar ratio of the total amount of polyisocyanate groups of all raw materials to the total amount of active hydrogen groups of all raw materials including the raw materials of the urethane prepolymer (D) (total NCO/total OH molar ratio) is 0.10 to 0.70. It is preferable to mix each raw material containing the polyalkylene oxide (B) so that the ratio is the same.

A urethane prepolymer ( E) and it is easy to stably form a more highly transparent urethane cured product.

Above all, it has an appropriate viscosity, and the residual amount of unreacted polyalkylene oxide (B) in the urethane prepolymer (E) is reduced, so that the urethane prepolymer (E) and the urethane cured product become more transparent, Since a large amount of polyalkylene oxide (B) can be introduced and strength and low tackiness are likely to be exhibited more remarkably, the final NCO/OH ratio is mixed at a ratio of 0.15 to 0.60. is preferred, and more preferably in the range of 0.20 to 0.50.

Among them, when using a polyisocyanate (C) such as hexamethylene diisocyanate or a derivative thereof having no difference in reactivity of NCO groups as the polyisocyanate (C), the final NCO/OH ratio is 0.20 to 0.40. When isophorone diisocyanate is used as the polyisocyanate (C), if the final NCO/OH ratio is in the range of 0.20 to 0.49, transparency tends to be good while suppressing gelation and high viscosity. therefore most preferred.

The weight ratio of polyalkylene oxide (A) to polyalkylene oxide (B) of all raw materials (polyalkylene oxide (A)/polyalkylene oxide (B)) is preferably in the range of 10/90 to 90/10, More preferably, it is in the range of 25/75 to 80/20, and most preferably in the range of 40/60 to 75/25, because it tends to exhibit higher strength while stably expressing transparency.

The average number of functional groups of the polyol, which is a combination of polyalkylene oxide (A), polyalkylene oxide (B), other polyols, and monool (AC), is not particularly limited. It is preferably in the range of 5-4.5 functionality, more preferably in the range of 2.8-3.9 functionality, most preferably in the range of 3.1-3.8. The average functional group number of polyol refers to the value obtained from the molar fraction and content of each raw material.

When the polyalkylene oxide (B) is used to form the urethane prepolymer (D), the polyalkylene oxide (B) used to form the active hydrogen group-terminated urethane prepolymer (E) is the NCO-terminated urethane prepolymer (D). The weight ratio ((E)-forming polyalkylene oxide (B)/(D)-forming polyalkylene oxide (B)) to the added amount of the polyalkylene oxide (B) used for the formation is 70/30 to 99.9. /0.1, more preferably 80/10 to 99/1, and most preferably 90/10 to 97/3.

For the formation of the urethane prepolymer (E), other additives such as polyols, monools, urethanization catalysts, solvents, plasticizers, leveling agents, reaction retarders and other additives may be added as necessary. . Moreover, when forming the urethane prepolymer (D), the added additives may remain as they are.

The other raw materials that are preferably included when forming the urethane prepolymer (E) are not particularly limited, but the same raw materials and amounts used as the other raw materials that are preferably included when forming the urethane prepolymer (D). and can be suitably applied.

Among them, the urethane prepolymer (E) is easy to suppress the increase in viscosity over time, has excellent storage stability, and is easy to improve handleability and curability while adjusting the viscosity to an appropriate level. may be added and is preferred.

When an organic solvent is used, the solid content concentration of the urethane prepolymer (E) is not particularly limited, but it is likely to exhibit good viscosity and good handling properties, so it should be contained in an amount ratio in the range of 60 to 99% by weight. is preferred, more preferably in the range of 80-97% by weight, most preferably in the range of 85-95% by weight. The urethanization catalyst containing a metal component is preferably contained in the urethane prepolymer (E) in an amount of 0.001 to 0.2% by weight, more preferably 0.003 to 0.003%. 0.1% by weight, most preferably 0.005-0.05% by weight.

The method for preparing the urethane prepolymer (E) is not particularly limited as long as the method can uniformly disperse and react the raw materials. Suitable reaction conditions can be employed.

When preparing the urethane prepolymer (E), although not particularly limited, the ratio of the NCO groups of the polyisocyanate (C) to the total amount of active hydrogen groups of the final polyol can be adjusted, desired tensile strength, coatability, solution In addition to the urethane prepolymer (D) and the polyalkylene oxide (B), a small amount of other polyols and monools (BC) may be added for adjusting the composition to obtain viscosity.

When adding other polyols and monools (BC) to the preparation of the urethane prepolymer (E) in addition to the polyalkylene oxide (B), if it is too much, the residual amount of unreacted components increases, resulting in deterioration of moldability and contamination resistance. Since the transparency of the resulting prepolymer and urethane cured product may deteriorate, it is preferable to add other polyols and monools in a total amount of 15 parts by weight or less per 100 parts by weight of the polyalkylene oxide (B). A molecular weight of less than 2,000 is preferable because a high molecular weight tends to result in poor compatibility and poor transparency.

Other polyols and monools (BC) can be appropriately selected from those that do not impair the transparency and physical properties of the prepolymer, and are not particularly limited. Examples include polycarbonate polyols, polytetramethylene glycol, polyolefin polyols, acrylic Commercially available polyols such as polyols, polyester polyols, Mannich polyols, sucrose polyols, aliphatic diamine polyols, polyethylene glycols, polycaprolactone polyols, fluorinated polyols, silicone-containing polyols, phosphorus-based polyols, polyoxyalkylene glycol monoalkyl Ethers, polyoxyalkylene glycol monoalkenyl ethers, polyoxyalkylene glycol monophenyl ethers, monools such as silicone-containing monools, low molecular weight organic compounds such as cyclohexanedimethanol, tetraethylene glycol, tripropylene glycol, tripropylene glycol monomethyl ether compounds and the like.

Among them, when added, it is preferable to contain sucrose polyol or polytetramethylene glycol because it has relatively good compatibility, tends to exhibit high transparency, and tends to increase strength, and in that case, it is difficult to increase the viscosity. It is preferably added in the range of 0.1 to 13 parts by weight, more preferably in the range of 0.5 to 10 parts by weight, because of its excellent handleability. Most preferably, the sucrose polyol is added in the range of 1 to 10 parts by weight, since it facilitates development of higher strength.

In addition, it is preferable not to use silicone components (monools, polyols, polyamines) having reactive groups and fluorine components having reactive groups because they tend to remain and contaminate, but are not particularly limited.
<Urethane prepolymer (E) composition>
The urethane prepolymer (E) is not particularly limited, but if necessary, the viscosity is adjusted by concentration or solvent addition, and additives such as chain extenders, antistatic agents, plasticizers, reaction retarders, leveling agents, and other Additives may be added and mixed to prepare the urethane prepolymer composition.

The chain extender is not particularly limited, and examples thereof include ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, pentaerythritol, and low molecular weights with a molecular weight of 1000 or less. Glycols such as polyalkylene glycol; and polyvalent amines such as ethylenediamine, N-aminoethylethanolamine, piperazine, isophoronediamine and xylylenediamine. Among them, polyvalent amines are preferable because they form urethane urea and easily obtain urethane having good physical properties.

Examples of the antistatic agent include, but are not particularly limited to, alkali metal salts and ionic liquids. salts, pyridinium salts and the like.

Examples of plasticizers include, but are not limited to, fatty acid esters, alicyclic esters, and polyether esters. Examples include epoxidized fatty acid esters, myristate esters, polyalkylene glycol terminal ester-modified compounds, and the like. mentioned.

The reaction retarder is not particularly limited. Inhibitors, etc.), additives that reduce the reactivity of isocyanates and polyol prepolymers (acid retarders, stabilizers, etc.) can be used, and such retarders can be used in combination. preferable.

Among them, as a reaction retarder, it is preferable to use one or more of an acid retardant, a chelate compound, a thickening inhibitor, and a stabilizer, more preferably an acid retardant, a chelate compound, and a thickening inhibitor. It is preferable to use 2 to 4 of any one of the agent and the stabilizer, and most preferably, 3 to 4 types including one or more of each of the acid retarder, chelate compound, and anti-thickening agent are used in combination. . Moreover, each of the acid retarder, chelate compound, and thickening inhibitor is not limited to one type, and two or more types can be used in combination, which is preferable.

Among them, it becomes easier to suppress the catalytic activity derived from the amine structure of the polyalkylene oxide (B), which extends the pot life and makes it easier to suppress rapid gelation during drying, aging, and coating. In addition, it preferably contains an acid retardant because it suppresses wrinkles and tends to improve moldability, and although it is not particularly limited, it 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 them, it is preferable to use a phosphorus-based acid retardant because it tends to achieve a good balance between reactivity and physical properties. The content of the acid retarder when used is preferably in the range of 0.001 to 1 part by weight, more preferably 0.005 to 0.1 part by weight, relative to 100 parts by weight of the prepolymer (E). is in the range of In addition, the pH of the urethane prepolymer (E) when using an acid retarder is preferably in the range of pH 4 to 9 because the curability tends to be high and the liquid property tends to be low corrosive. The pH of the urethane prepolymer (E) refers to the value measured with a pH meter after dispersing it in a liquid mixture of water and IPA at a weight ratio of 5:3 at a solid content of 7% by mass.

As the chelate compound, one or more of a keto-enol tautomer compound and a triazole derivative are included because it is easy to adjust the catalytic activity to suppress thickening after mixing with the cross-linking agent and to improve moldability. is preferred, and it is more preferred to use one or more (total of two or more) each of a ketoenol tautomeric compound and a triazole derivative as the chelate compound.

Although the keto-enol tautomer compound is not particularly limited, it is preferably one or more of ethyl acetoacetate and acetylacetone, since it is easy to adjust the catalytic activity and improve moldability. When such a ketoenol tautomer compound is included, its content is such that the moldability tends to be better, so the molar ratio (ketoenol tautomer compound/metal catalyst) with respect to the urethanization catalyst containing the metal component is 10 times or more. preferably in the range of 50 to 5,000 times, preferably in the range of 0.01 to 20 parts by weight, more preferably 0 .5 to 10 parts by weight.

The triazole derivative is not particularly limited, but is preferably a benzotriazole derivative having a phenolic hydroxyl group, more preferably a urethane derivative, because it has a high effect of suppressing curing shrinkage and easily forms a urethane with a good coating film appearance. A benzotriazole derivative having a phenolic hydroxyl group in which an aryl group containing a phenolic hydroxyl group is directly linked to benzotriazole is preferable, since it is liquid at room temperature and has a molecular weight in the range of 300 to 700, since the transparency tends to be high. Examples include, but are not limited to, 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (BASF Tinuvin 571), 3-(2H-benzotriazol-2-yl)-5 -(1,1-dimethylethyl)-4-hydroxy-benzenepropionic acid having 7 to 9 carbon atoms (tinuvin 99-2, tinuvin 384-2 manufactured by BASF) and the like. When the triazole derivative is used, the content is preferably in the range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the urethane prepolymer (E). is more preferably in the range of 0.2 to 2 parts by weight, and most preferably in the range of 0.3 to 1.5 parts by weight.

When a ketoenol tautomer compound and a triazole derivative are used in combination as a chelate compound, the ratio of the mixed weight should be the weight of the ketoenol tautomer compound relative to the triazole derivative, since wrinkles in the resulting urethane are likely to be suppressed and moldability is likely to be good. The ratio (ketoenol tautomeric compound/triazole derivative) is preferably 0.5 or more and 50 or less, more preferably 2 or more and 20 or less.

Examples of thickening inhibitors include, but are not limited to, compounds that delay the increase in molecular weight and degree of cross-linking associated with thickening during reaction, and compounds that suppress thickening even when molecular weight increases due to reaction.

For example, a compound that has reactivity with an isocyanate cross-linking agent and retards the increase in molecular weight by proceeding with the reaction of the main prepolymer (E) and the isocyanate cross-linking agent (F) in parallel/or preferentially, the molecular weight increase compounds that suppress/or reduce the degree of increase in the viscosity of the system by improving the affinity or changing the structure associated with this.

Among them, the thickening inhibitor is preferably a compound having a lower molecular weight than the prepolymer (E) and having an active hydrogen group reactive with the isocyanate cross-linking agent (F). By including, the reaction of the main prepolymer (E) and the isocyanate cross-linking agent (F) proceeds in parallel / or preferentially, and the cross-linking between the prepolymers is suppressed, making it easy to suppress thickening.

Such a thickening inhibitor has a molecular weight of 1,000, which tends to increase the reactivity of active hydrogen groups, because the reaction tends to proceed preferentially over the main agent, and it is easy to suppress cross-linking between prepolymers to suppress thickening. The following compounds are preferred. Among them, if the molecular weight is too low, the reactivity of the active hydrogen group becomes too high, and the reaction is consumed at an early stage, the period during which thickening can be suppressed is shortened, and the reaction retardation effect is reduced. If the molecular weight is too high, the viscosity tends to increase during the reaction, and the reactivity of the active hydrogen groups also decreases, making it easier for the base resin to react with each other. Preferably, the molecular weight is in the range of 60-700, more preferably in the range of 90-300, and most preferably in the range of 100-160. In addition, as such a thickening inhibitor, the degree of cross-linking is less likely to decrease during the reaction and the tensile strength is less likely to decrease. preferable. Among them, if there are too many active hydrogen groups, the degree of cross-linking tends to increase during the reaction between the anti-thickening agent and the isocyanate cross-linking agent, and the anti-thickening effect tends to decrease. It preferably has an active hydrogen group such as a group, a thiol group, more preferably has 2 to 3 hydroxyl groups in one molecule, and most preferably has moderate reactivity and a remarkable effect of suppressing thickening. It is a diol having two primary hydroxyl groups in one molecule because it tends to have a high molecular weight. When using a thickening inhibitor, the content is preferably in the range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the urethane prepolymer (E). urethane is easily formed, it is more preferably in the range of 0.2 to 2 parts by weight, most preferably 0.3 to 1.5 parts by weight, relative to 100 parts by weight of the urethane prepolymer (E). Range. In addition, when the thickening inhibitor has an active hydrogen group, the thickening inhibitory effect tends to be high while maintaining the physical properties of the urethane. It is preferable to add an anti-thickening agent within the range, more preferably within the range of 5 to 20 mol %.

Examples of stabilizers include, but are not limited to, compounds that suppress the reactivity of isocyanates and polyol prepolymers, such as phenolic antioxidants. In addition, this embodiment does not contain a triazole derivative as a stabilizer. By increasing the amount of such an antioxidant to 1000 ppm or more, preferably 3000 ppm or more, and most preferably 5000 ppm to 20000 ppm, the isocyanate or polyol prepolymer is stabilized to reduce reactivity and increase viscosity. It is preferable because it is easy to suppress. Among them, it is preferable to use BHT, which is easily available and has good compatibility with urethane, or a hindered phenol-based antioxidant having a molecular weight of 1,000 or less (Irganox series, etc.). Irganox 1135, Irganox 1726, and the like are preferable because the transparency of the resulting urethane tends to be high if they are liquid at room temperature, but if they have a highly compatible structure such as BHT, Irganox 1076, and Irganox 1010, prepolymers can be used. It is suitable for use because it is dispersed uniformly in a liquid and does not easily deteriorate transparency during urethane formation.

The content of the stabilizer when used is preferably in the range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the urethane prepolymer (E). The content of the stabilizer is more preferably in the range of 0.2 to 2.5 parts by weight, most preferably in the range of 0.5 to 2 parts by weight, because urethane is easily formed.

The mixing process of these additives may be carried out at room temperature, since there is little change in weight due to volatilization, or may be carried out with heating to improve solubility and mixability. Also, the mixing method is not particularly limited. In the concentration step, which is performed as necessary, there is no particular limitation as long as the method can adjust the concentration to a predetermined level, such as bubbling with nitrogen or the like, heating, or pressure reduction.

A urethane prepolymer composition solution containing a urethane prepolymer (E), an organic solvent, and an additive, which is one aspect of the present invention, has excellent handling properties and is easy to handle. It is preferable to mix them in the same amount ratio, more preferably in the range of 70 to 97% by weight, and most preferably in the range of 85 to 95% by weight. In addition, it is more preferable that the viscosity is in the range of 3 to 50 Pa s at 25 ° C., because the urethane cured product tends to be stably highly transparent due to excellent handling properties such as mixing and coating of the cross-linking agent. is in the range of 5 to 30 Pa·s.

Although the transparency of the urethane prepolymer composition solution is not particularly limited, it is preferably transparent, and such a property can be easily obtained by containing the urethane prepolymer (E) of the present invention. In particular, the haze at a thickness of 1 cm is preferably 15% or less, more preferably 5% or less.
<Method for producing cured urethane and urethane coating>
The urethane prepolymer (E) and the urethane prepolymer composition using it can be reacted and cured (solidified) by various methods to produce a cured urethane product. The method for producing a cured urethane product is not particularly limited. It can be produced by carrying out a urethanization reaction, a urea formation reaction, and, if necessary, drying at room temperature or at a high temperature of 150° C. or lower in the presence of a stabilizer, a chain extender, a cross-linking agent, other additives, and the like.

Among them, it is preferable to contain an isocyanate compound (F) as a cross-linking agent because it is easy to exhibit high curability and high transparency more stably, and the urethane prepolymer (E) and the isocyanate compound (F) are included. It preferably contains a urethane-forming composition or a urethane-forming composition solution containing the aforementioned urethane prepolymer composition solution and the isocyanate compound (F).

The isocyanate compound (F) used as the cross-linking agent is not particularly limited, but the same polyisocyanate as the above-mentioned polyisocyanate (C) can be exemplified and can be preferably used. The isocyanate compound (F) and the isocyanate compound (C) may be the same or different.

Although the content of the isocyanate compound (F) in the urethane-forming composition and the urethane-forming composition solution is not particularly limited, the urethane prepolymer (E) has excellent curability and tends to be highly transparent. The ratio (M _NCO /M _OH ) of the amount (M _NCO ) of isocyanate groups derived from the isocyanate compound (F) to the total amount (M _OH ) of derived hydroxyl groups and hydroxyl groups derived from other active hydrogen compounds is 0. It is preferably 0.5 or more and less than 4.0, more preferably 0.7 or more and less than 2.5 in terms of molar ratio. In addition, the weight ratio of the urethane prepolymer (E) to the isocyanate compound (F) (weight of (E)/weight of (F)) is 99, since higher transparency, higher curability, and higher strength are likely to occur. /1 to 50/50, more preferably 90/10 to 70/30.

Although the viscosity of the urethane-forming composition and the urethane-forming composition solution at 25°C is not particularly limited, it is usually 0.001 Pa s or more and 100 Pa s or less. Therefore, it is 0.2 Pa·s or more and 30 Pa·s or less, more preferably 0.5 Pa·s or more and 10 Pa·s or less. Here, since the coatability is remarkably excellent when coated with a coating machine or the like, it is possible to obtain a urethane coating film with a uniform thickness, so it is not particularly limited, but it is preferable to form and cure the coating film. . In addition, a coating film of the cured urethane is formed on a base substrate such as a PET film or COP film by various methods, and if necessary, bonding or molding with another substrate such as release PET or release paper is performed. can form a polyurethane sheet having the urethane coating on the substrate.

Among them, a step of mixing the urethane prepolymer (E) obtained by the present invention with an additive and an isocyanate cross-linking agent (F), a step of coating a substrate with a thickness of 10 to 500 μm, and a temperature of 70 to 160° C. for 30 seconds. By passing through the step of drying and curing under conditions of up to 10 minutes, a urethane coating film with high transparency and low tackiness can be produced with high productivity, which is preferable. More preferably, it is excellent in curability, and it is easy to obtain a highly transparent coating film with a uniform thickness from a thin film to a high thickness. It is preferable to include the step of coating.

In addition, since the urethane prepolymer (E) has an aromatic amine residue around the molecular end, it has remarkably high initial curability, does not easily flow even at high temperatures, and is rapidly cured with little unevenness in thickness. It is preferable to dry and cure in the range of 1 minute to 8 minutes, and more preferably dry and cure in the range of 2 minutes to 6 minutes at 120 to 145 ° C. because the productivity of the urethane coating film is more likely to be excellent. .

Cured urethane products and urethane coatings are not particularly limited in their uses, and can be used in any application where ordinary polyurethanes are used, but they are particularly suitable for applications requiring mechanical properties, viscous/adhesive properties, etc. It can be used preferably. Specifically, sealing materials for construction and civil engineering, adhesives such as elastic adhesives for construction, packing tapes and surface protection films, various adhesives represented by optics, paints, elastomers, waterproof coating materials, flooring materials, Applications such as plasticizers, flexible polyurethane foams, semi-rigid polyurethane foams, and rigid polyurethane foams are exemplified and can be preferably used.

Among them, there are strong demands for mechanical properties and adhesion/adhesive properties for polyurethane, and workability and coatability are required, so it is particularly preferable to use it as a sealant, paint, pressure sensitive adhesive, or adhesive.

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention should not be construed as being limited to the following examples as long as the gist thereof is not exceeded. The raw materials and evaluation methods used in the following examples and comparative examples are as follows.
(Raw material 1) Polyalkylene oxide (A) used in Examples and Comparative Examples, or other polyols and monools (AC)
The properties of polyalkylene oxides, other polyols, and monools (AC) used in Examples and Comparative Examples were obtained by the following methods.
<Unsaturation of polyalkylene oxide>
The degree of unsaturation of the polyalkylene oxide was measured by scanning 800 times according to the NMR method described in Kobunshi Ronbunshu 1993, 50, 2, 121-126.
The NMR measurement was performed using deuterated chloroform as a heavy solvent and using a JEOL 400 MHz NMR ECZS as a measuring device.
<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. Also, 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.
<Molecular weight distribution (Mw/Mn) of polyalkylene oxide>
The molecular weight distribution (Mw/Mn) of polyalkylene oxide was measured by the following procedure using gel permeation chromatography (GPC).

10 mg of polyalkylene oxide and 10 ml of tetrahydrofuran (THF) are placed in a sample bottle, left to stand for one day to dissolve the polyalkylene oxide in THF, and filtered through a PTFE cartridge filter (0.5 μm) to obtain a sample for GPC measurement. A sample of

For GPC measurement, THF is used as a developing solvent, measurement is performed at a column temperature of 40 ° C., and a cubic approximate curve using 8 standard polystyrenes manufactured by Tosoh Corporation with a known molecular weight is used as a calibration curve to determine the molecular weight distribution (Mw / Mn). I did the analysis. HLC-8320GPC manufactured by Tosoh Corporation was used as a measurement apparatus, and HLC-8320GPC-ECOSEC-WorkStation manufactured by Tosoh Corporation was used for analysis.
<Viscosity of polyalkylene oxide>
The viscosity of polyalkylene oxide was determined according to the method described in JIS K-1557-5. Specifically, it was measured using a cone/plate rotational viscometer at a temperature of 25° C. and a shear rate of 0.1 (1/s).
(Raw Material 1-1) Polyalkylene oxide (A) used in Examples and Comparative Examples
The polyalkylene oxide (A1) uses an imino group-containing phosphazenium salt (hereinafter referred to as an IPZ catalyst) and triisopropoxyaluminum in combination to sufficiently dehydrate and remove the solvent, and is bifunctional polyoxypropylene having a molecular weight of 400. It was obtained by adding sufficiently dehydrated propylene oxide to glycol. (A1) is a polyoxypropylene glycol (diol) having only a propylene oxide group as an alkylene oxide group and two hydroxyl groups in one molecule.

The polyalkylene oxide (A2) uses an IPZ catalyst and triisopropoxyaluminum in combination in the same manner as in (A1), adds a propylene oxide group as an alkylene oxide group, removes the propylene oxide remaining in the system, and then blocks ethylene oxide. and is a diol with a low degree of unsaturation containing primary hydroxyl groups.

Polyalkylene oxide (A4) uses a trifunctional polyoxypropylene triol having a molecular weight of 600 as an initiator, uses an IPZ catalyst and triisopropoxyaluminum in combination in the same manner as in (A2), and adds a propylene oxide group as an alkylene oxide group. After removing the propylene oxide remaining in the system, ethylene oxide is added in blocks, and the triol contains a primary hydroxyl group and has a low degree of unsaturation.

For the polyalkylene oxide (A3), Sannics PP-3000 manufactured by Sanyo Chemical Industries, Ltd., which is a polypropylene glycol synthesized by adding only propylene oxide by a conventional method, was used.

The properties of (A1) to (A4) are shown in Table 1. (A1), (A2), and (A4) have an extremely small amount of unsaturated monol (extremely low degree of unsaturation) and a narrow molecular weight distribution. (A3) is a polyalkylene oxide having a general degree of unsaturation and molecular weight distribution.
All of the polyalkylene oxides (A1) to (A4) used in the examples were used after heating and vacuum dehydration. Moreover, the polyalkylene oxide produced using the IPZ catalyst was used after removing the catalyst including aluminum.
(Raw materials 1-2) Other polyols and monools (AC) used in Examples and Comparative Examples
Monool (AC1) is a bifunctional polyoxytetramethylene glycol having a molecular weight of 2,100 and having a molecular weight of 2,000 or more and having no alkylene oxide residue.

(Raw material 2) Polyalkylene oxide (B)
(Raw materials 2-1) Polyalkylene oxides (B1), (B2), and (B3) used in the examples
Polyalkylene oxide (B1) is a commercially available tolylenediamine-based polypropylene glycol, which has a nominal functionality of 4.0, a hydroxyl value of 356 mgKOH/g, and a viscosity of 9500 mPa s at 25°C. AR-2589 was used. The molecular weight calculated from this property is 630, and the aromatic amine residue content is 19%.

Polyalkylene oxide (B2) is a commercially available tolylenediamine-based polypropylene glycol/polyethylene glycol copolymer having a nominal functional group number of 4.0, a hydroxyl value of 413 mgKOH/g, and a viscosity of 15000 mPa s at 25°C. Sannics HM-551 manufactured by Sanyo Chemical Industries was used. The molecular weight calculated from this property is 540, and the aromatic amine residue content is 22%.

Polyalkylene oxide (B3) is a commercially available tolylenediamine/glycol combined initiation system polyalkylene oxide, which has a nominal functionality of 3.2, a hydroxyl value of 310 mgKOH/g, and a viscosity of 2200 mPa s at 25°C. JEFFOLAD-310 manufactured by the company was used. Calculated from this property, the initiator molar ratio is aromatic amine/glycol=6/4, the molecular weight is 580, and the aromatic amine residue content is 12%.
(Raw materials 2-1) Active hydrogen compounds (BC1), (BC2), and (BC3) used in Examples and Comparative Examples
As the active hydrogen compound (BC1), Sannics GP600 manufactured by Sanyo Chemical Industries, Ltd., which is a commercially available trifunctional polypropylene triol with a molecular weight of 600, was used.
As the active hydrogen compound (BC2), O-855W manufactured by Toho Chemical Industry Co., Ltd., which is a sucrose-based polyol having a nominal number of functional groups of 8.0 and a molecular weight of 1,190, was used.
2,4-tolylenediamine, which is an aromatic amine having 4 functional groups, was used as the active hydrogen compound (BC3).

The active hydrogen compound (BC1) is a polyalkylene oxide having a molecular weight equivalent to that of the polyalkylene oxide (B1) having an aromatic amine residue and having no aromatic amine residue, and the active hydrogen compound (BC2) is an aromatic amine. It is a polyalkylene oxide containing a sucrose residue that has no residue but has a rigid cyclic sugar structure with a high number of functional groups. is a compound that does not have
(Raw material 3) Isocyanate compounds (C) and (F) used in Examples and Comparative Examples
In Examples and Comparative Examples, the following three types were used as the isocyanate compounds (C) and (F).

Isocyanate compound (C1): isophorone diisocyanate (IPDI). (C1) is a diisocyanate having a primary NCO group and a secondary NCO group as isocyanate groups.

Isocyanate compound (C2): 1,6-hexamethylene diisocyanate (HDI). (C2) is a diisocyanate having only primary NCO groups as isocyanate groups.

Isocyanate compound (F1): Coronate HXLV manufactured by Tosoh Corporation, which is a modified isocyanate of 1,6-hexamethylene diisocyanate (HDI), and the average functionality of the isocyanate group in (F1) is 3.2.
(Raw Material 4) Urethane Catalyst In Examples and Comparative Examples, a urethanization catalyst was added as an additive. As the urethanization catalyst, Nasem iron manufactured by Nippon Kagaku Sangyo Co., Ltd., which is iron trisacetylacetonate (abbreviation: Fe(acac)3), was used. This catalyst was added as a masterbatch of 5% solution in order to improve workability. In the table, the added amount without solvent is described.
(Raw Material 5) Solvent In Examples and Comparative Examples, methyl ethyl ketone (abbreviation MEK) manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. and triethylene glycol dimethyl ether (abbreviation TEGDM) manufactured by Toho Chemical Industry Co., Ltd. were used as solvents.
(Production example of urethane prepolymer (D) and urethane prepolymer (E))
Polyalkylene oxide (A), which is a raw material for urethane prepolymer (D), polyalkylene oxide (B) and monool (AC) added as necessary are added to a four-neck eggplant flask and heated at 100 ° C. for 1 Vacuum dehydration was performed for more than 1 hour to remove water.
Then, in the system using a solvent after cooling to 50° C. or less, after adding the solvent, isocyanate, and catalyst masterbatch, the temperature was raised to a predetermined temperature, and the reaction was started when the predetermined temperature was reached. After the reaction for 3 hours, it was confirmed by FT-IR that NCO groups remained and no change was observed in liquid properties or no change was observed in the amount thereof, and an NCO group-terminated urethane prepolymer (D ).

After cooling to 60°C or less, a predetermined amount of polyalkylene oxide (B) was added to the urethane prepolymer (D). It was allowed to warm to initiate the reaction. After reacting for 3 hours, it was confirmed by FT-IR that the NCO groups had disappeared and that the liquid properties had not changed, to obtain an active hydrogen group-terminated urethane prepolymer (E). Concentration was performed as necessary to adjust the viscosity.
The internal temperature was cooled to 50° C. or less, various additives were mixed and uniformly dispersed as necessary, and insoluble matter was removed through a SUS wire mesh to obtain a urethane prepolymer (E) composition.
(Evaluation items of urethane prepolymer)
<Liquid Transparency>
The transparency of the urethane prepolymer was evaluated according to the following criteria.

◎ (pass): when visually transparent (liquid haze is 5% or less)
Good (acceptable): Slight turbidity is visually observed, but the haze of the liquid is 15% or less (substantially transparent).

x (failed): when visually clear strong turbidity is observed, or when the haze of the liquid exceeds 15%.
<Curability>
Add 1.1 equivalents of HDI isocyanurate cross-linking agent Coronate HXLV to the hydroxyl group of the active hydrogen group-terminated urethane prepolymer, apply it to the PET substrate at 80 μm or less, and dry at 130 ° C. for 5 minutes. The cured urethane product was evaluated by finger touch according to the following criteria.

◎ (Pass): Tack disappeared, and significantly higher strength and easy peelability can be expected.

○ (Pass): When tack is slight and remarkably high strength and easy peelability can be expected.

× (failed): When tackiness is large and curing is insufficient, and remarkably high strength and easy peelability cannot be expected.

In addition, a release PET Purex A31 of 20 cm×20 cm was attached to the urethane cured product obtained by the above curability evaluation, and the handleability of the urethane cured product was evaluated according to the following criteria.
<Handleability>
⊚: No lifting, peeling, or cracking even after bending within about 30°.

◯: When bent within about 30°, lift was observed, but there was no crack and no peeling.

△: When it is peeled off or cracked when it is bent within about 30°. Judged that winding misalignment, position misalignment during bonding, and brittle fracture are likely to occur.

Those that passed both the transparency and the curability were judged to pass because they were urethane prepolymers with active hydrogen group ends that could be expected to have high transparency, low tackiness, remarkably high strength, and easy peelability. In addition, it was judged that the cured urethane products with excellent handleability of ⊚ and ◯ were also excellent in handleability of the cured urethane products.
<Example>
(Example 1)
60 parts by weight of polyalkylene oxide (A1) is added according to the composition ratios described in Production Example 1 of Urethane Prepolymer (D) and Urethane Prepolymer (E) and Synthesis Example 1 in Table 2 for dehydration to give an isocyanate compound. (C1) and 0.02 parts by weight of iron trisacetylacetonato as a urethanization catalyst, the amount of hydroxyl groups derived from (A1) (M _OH ) and the amount of isocyanate groups derived from (C1) (M _NCO ) are The mixture was prepared so that the molar ratio of M _NCO of (C1)/M _OH of (A1) was 1.86, and reacted at a constant temperature of 70° C. for 3 hours to obtain an NCO group-terminated urethane prepolymer (D). got After cooling, 40 parts by weight of the polyalkylene oxide (B1) is added to the urethane prepolymer (D), the reaction is completed under the same reaction conditions as in the production of the urethane prepolymer (D), and the final isocyanate compound ( An active hydrogen group-terminated urethane prepolymer (E1) having an MNCO of C)/MOH of (A1) and (B1) of 0.15 was obtained.

The active hydrogen group-terminated urethane prepolymer (E1) is obtained by adding only the aromatic amine polyol after synthesizing the NCO group-terminated urethane prepolymer (D). % is the aromatic amine polyol structure, and the aromatic amine polyol content ratio in the total polyol is higher than 85.1 mol %. Table 3 shows the results of Example 1. The urethane prepolymer (E1) is highly transparent with no gels or precipitates, has remarkably good initial curability, and can be expected to have remarkably high strength. Cured urethane products also have good wettability and flexibility. It was excellent in handleability and had high transparency.
(Examples 2 to 13)
Manufactured by using various solvents according to the composition ratios described in Synthesis Examples 2 to 13 in Table 2 with respect to Example 1, and changing the types of polyalkylene oxides (A) and (B) and the ratio of the amount charged. It is. An NCO group-terminated urethane prepolymer (D) was produced in the same manner as in Example 1, and the reaction was completed by mixing with a polyalkylene oxide (B) having an aromatic amine residue to obtain an active hydrogen group-terminated urethane prepolymer. Since the polymer (E) was produced, theoretically, 100% of the molecular terminals having active hydrogen groups have an aromatic amine polyol structure, which is higher than the aromatic amine polyol content ratio in the total polyol. .

Table 3 shows the results of Examples 2-13. In Examples 5 and 13, the content and content ratio of the polyol structure having a rigid aromatic amine residue is high, and the urethane prepolymer (E) is slightly cloudy and has slightly low wettability. Although the content and content ratio of the polyol structure with rigid aromatic amine residues was low, slight tack was observed, but both were highly transparent with no gels or precipitates, and the initial curability was remarkable. Good and remarkably high strength can be expected, and all of the urethane cured products were highly transparent.

(Examples 14-16)
After synthesizing an NCO group-terminated urethane prepolymer (D) according to Synthesis Examples 14 to 16 shown in Table 4, a polyalkylene oxide (B3) containing glycol was added as a polyol having an aromatic amine residue. . The molar ratio of the tetrafunctional aromatic amine and the bifunctional glycol is 6/4, and the polyol having the tetrafunctional aromatic amine residue has a higher number of functional groups and has an amine structure with catalytic activity to react. Therefore, 60% or more of the molecular ends having active hydrogen groups are aromatic amine polyol structures, which is higher than the aromatic amine polyol content ratio in all polyols. Table 5 shows the results of Examples 14-16. The urethane prepolymer (E) is highly transparent with no gels or precipitates, has remarkably good initial curability, and can be expected to have remarkably high strength. The cured urethane product also has good wettability and flexibility. It was excellent in handleability and had high transparency.
(Examples 17-22)
After synthesizing an NCO group-terminated urethane prepolymer (D) according to Synthesis Examples 17 to 22 shown in Table 4, in addition to a polyol having an aromatic amine residue, a small amount of polyol not containing an aromatic amine residue is used in combination. It is added by None of the polyols used in combination has an amine structure with catalytic activity, and is presumed to have the same molecular weight or higher and low reactivity. Most of the molecular terminals having active hydrogen groups are aromatic amine polyol structures, and the aromatic amine polyol content ratio in all polyols is higher than that of all polyols. Table 5 shows the results of Examples 17-22. The urethane prepolymer (E) is highly transparent with no gels or precipitates, has remarkably good initial curability, and can be expected to have remarkably high strength. The cured urethane product also has good wettability and flexibility. It was excellent in handleability and had high transparency.
(Example 23)
According to Synthesis Example 23 described in Table 4, a polyalkylene oxide (A3) having a general degree of unsaturation and molecular weight distribution is used instead of a polyalkylene oxide (A1) having a low degree of unsaturation to produce a urethane prepolymer (E). It is manufactured. Table 5 shows the results. Even when polyalkylene oxide (A3), which has a general degree of unsaturation and molecular weight distribution, is used, it has a high polyalkylene oxide structure with an aromatic amine residue at the molecular end, so there are no gels or precipitates. It is a urethane prepolymer (E) that can be expected to have transparency, high curability, and strength of a cured urethane product.
(Example 24)
According to Synthesis Example 24 described in Table 4, in addition to polyalkyne oxide (B) having a rigid aromatic amine residue, a rigid cyclic sucrose structure with a high functional group is added to Example 23. By using a small amount of the polyalkylene oxide (BC1) having the polyalkylene oxide (BC1), it is possible to obtain a urethane prepolymer (E) that can be expected to have a higher degree of curability while maintaining a high degree of transparency, and that the urethane cured product will have a higher strength.
(Example 25)
After synthesizing an NCO group-terminated urethane prepolymer (D) using polyalkyloxide (A2) having an ethylene oxide residue at the molecular end and a high ratio of primary hydroxyl groups according to Synthesis Example 25 described in Table 4. , which is a urethane prepolymer (E25) synthesized by adding only a polyalkyloxide (B1) having only a propylene oxide residue and an aromatic amine residue with almost no primary hydroxyl groups.

Since the urethane prepolymer (E25) has almost no primary hydroxyl groups derived from the polyalkylene oxide (A2), it is shown that the polyalkyl oxide (B1) having aromatic amine residues is unevenly distributed at the molecular ends. It was shown to be higher than the aromatic amine polyol content ratio in all polyols. Table 5 shows the results of Example 25. The urethane prepolymer (E25) is highly transparent with no gels or precipitates, has remarkably good initial curability, and can be expected to have remarkably high strength. Cured urethane products also have good wettability and flexibility. It was excellent in handleability and had high transparency.

All of the urethane prepolymers (E) obtained in this example are highly transparent regardless of the reaction conditions such as the amount of solvent, and almost no gel-like matter, deposits on the flask wall, sedimented components, etc. are observed. Viscosity was also in the range of 1 to 100 Pa·s, and good fluidity was exhibited. Moreover, all of the urethane cured products obtained by the curability evaluation had no shrinkage and were visually highly transparent, and had a haze of 5% or less.

As described above, the localization and maldistribution of the aromatic amine polyol around the ends of the molecules makes the urethane prepolymer (E) highly transparent and exhibits remarkably good initial curability. It was shown by the appearance that a significantly higher strength can be expected.

<Comparative example>
(Comparative example 1)
A urethane prepolymer (EC1) having no polyalkylene oxide structure and having aromatic amine residues unevenly distributed at the molecular ends, synthesized according to the composition ratio shown in Synthesis Example 26 in Table 6 (EC1). A polyalkylene oxide (B2) having an ethylene oxide residue was used to form the urethane prepolymer (EC1). is shown to be a polyol structure derived from a polyalkylene oxide (A1) having no aromatic amine residue, and the content of the polyalkylene oxide structure having an aromatic amine residue in the entire molecular terminal It has a low content of polyalkylene oxide structures having aromatic amine residues. Table 7 shows the results of Comparative Example 1. In the composition ratio and solid content of Synthesis Example 26, significant cloudiness was observed due to deterioration of compatibility, and the urethane prepolymer with active hydrogen group ends was opaque and difficult to use, and the urethane cured product was stably highly transparent. was a urethane prepolymer that was difficult to produce.
(Comparative example 2)
After synthesizing an NCO group-terminated urethane prepolymer (DC2) according to the composition ratio described in Synthesis Example 27 in Table 6, only an active hydrogen compound (BC1) having an equivalent molecular weight and no aromatic amine residue was terminated. A urethane prepolymer (EC2) having no aromatic amine residue obtained by addition. Table 7 shows the results of Comparative Example 2. Since it does not have a rigid aromatic amine residue, it is poor in curability and difficult to use, and the strength of the cured urethane obtained cannot be expected.
(Comparative Example 3)
After synthesizing an NCO group-terminated urethane prepolymer (DC3) according to the composition ratio described in Synthesis Example 28 in Table 6, a sucrose residue having a rigid cyclic structure instead of having no aromatic amine residue was added. It is a urethane prepolymer (EC3) having no aromatic amine residue obtained by adding only an active hydrogen compound (BC2) having to the terminal. Table 7 shows the results of Comparative Example 3. Since it does not have aromatic amine residues and has many rigid sucrose residues, it has poor transparency and is difficult to use.
(Comparative Example 4)
According to the composition ratio described in Synthesis Example 29 in Table 6, after synthesizing an NCO group-terminated urethane prepolymer (DC4) using polytetramethylene glycol that does not have an alkylene oxide residue having 3 or more carbon atoms, An aromatic amine having no alkylene oxide residue having 3 or more carbon atoms obtained by adding an active hydrogen compound (BC3), which is an aromatic amine having no 3 or more alkylene oxide residues, to the terminal and having an aromatic amine at the molecular end A urethane prepolymer (EC4) that does not have a polyalkylene oxide structure with residues. Table 7 shows the results of Comparative Example 4. Since it does not contain alkylene oxide residues having 3 or more carbon atoms and does not have alkylene oxide residues in the aromatic amine, it has poor compatibility and is opaque and difficult to use, and the resulting urethane cured product cannot be expected to have transparency. It was something.
(Comparative Example 5)
After synthesizing an NCO group-terminated urethane prepolymer (DC5) according to the composition ratio described in Synthesis Example 30 in Table 6, an active hydrogen compound that is an aromatic amine having no alkylene oxide residue having 3 or more carbon atoms ( A urethane prepolymer (EC5) having no polyalkylene oxide structure and having an aromatic amine residue at the molecular terminal, obtained by adding BC3) to the terminal. Table 7 shows the results of Comparative Example 5. Since it does not have a polyalkylene oxide structure at the molecular terminal, it has poor compatibility, is opaque, and is difficult to use, and the obtained urethane cured product cannot be expected to have transparency.
(Comparative Example 6)
After synthesizing an NCO group-terminated urethane prepolymer (DC6) having a polyalkylene oxide structure having an aromatic amine residue according to the composition ratio described in Synthesis Example 31 in Table 6, it does not have an aromatic amine residue. A urethane prepolymer (EC6) obtained by adding only an active hydrogen compound (BC1) to the terminal and having a polyalkylene oxide structure having an aromatic amine residue only inside the molecule and not at the terminal. Table 7 shows the results of Comparative Example 6. Curability is poor because it does not have a polyalkylene oxide structure with an aromatic amine residue at the molecular end, compatibility is poor, opacity makes it difficult to use, and transparency of the cured urethane obtained cannot be expected. Met.
(Comparative Example 7)
After synthesizing an NCO group-terminated urethane prepolymer (DC7) having a polyalkylene oxide structure having an aromatic amine residue according to the composition ratio described in Synthesis Example 32 in Table 6, it does not have an aromatic amine residue. A urethane prepolymer (EC7) obtained by adding only an active hydrogen compound (BC2) to the terminal and having a polyalkylene oxide structure having an aromatic amine residue only inside the molecule and not at the terminal. Table 7 shows the results of Comparative Example 7. Since it does not have a polyalkylene oxide structure having an aromatic amine residue at the molecular end, the compatibility is remarkably poor and it is opaque and difficult to use.
(Comparative Example 8)
According to the composition ratio described in Synthesis Example 33 in Table 6, after synthesizing an NCO group-terminated urethane prepolymer (DC8) having a polyalkylene oxide structure having an aromatic amine residue, it does not have a polyalkylene oxide residue. A urethane prepolymer (EC8) obtained by adding only an active hydrogen compound (BC3) to the terminal and having a polyalkylene oxide structure having an aromatic amine residue only inside the molecule and not at the terminal. Table 7 shows the results of Comparative Example 8. Since it does not have a polyalkylene oxide structure at the molecular end, compatibility is remarkably poor, and it is opaque and difficult to use, and the obtained urethane cured product cannot be expected to have transparency.
(Comparative Examples 9-11)
According to the composition ratios described in Synthesis Examples 34 to 36 in Table 6, after synthesizing an NCO group-terminated urethane prepolymer (DC) having a polyalkylene oxide structure having an aromatic amine residue, a small amount of aromatic amine residue and a polyol (BC1) that does not contain excessive aromatic amine residues, and many of the molecular ends have a polyol structure that does not contain aromatic amine residues. Table 7 shows the results of Comparative Examples 9-11. Even if the content of the polyol structure containing the aromatic amine residue is slightly changed, since most of the molecular ends are polyol structures that do not contain the aromatic amine residue, the curability is insufficient and it is difficult to use. The strength of the obtained urethane cured product could not be expected.
(Comparative Example 12)
After synthesizing an NCO group-terminated urethane prepolymer (DC12) having a polyalkylene oxide structure having an aromatic amine residue according to the composition ratio described in Synthesis Example 37 in Table 6, it has a small amount of aromatic amine residue. A polyol and a polyol (BC2) containing a sucrose residue but not containing an excess aromatic amine residue are added in combination, and most of the molecular ends have a polyol structure containing a sucrose residue. . Table 7 shows the results of Comparative Example 12. Many of the molecular ends have a polyol structure containing a rigid sucrose residue that does not contain an aromatic amine residue. It was unexpected.

As shown in the comparative examples above, when the polyol structure having aromatic amine residues localized and unevenly distributed around the molecular end is not included, transparency and curability are stably affected by the amount of solvent and reaction conditions. However, it is difficult to use it because it is difficult to express it in the urethane, and it is difficult to stably form a highly transparent and high strength urethane cured product.

<Production example of urethane cured product>
Per 100 parts by weight of the solid content of the urethane prepolymers (E) of Examples 2, 12, 18, and 25, 5 parts by weight of acetylacetone as a reaction retarder and 600 ppm of an acidic phosphoric acid ester (JP508 manufactured by Johoku Kagaku Kogyo Co., Ltd.), triazole stable 0.8 parts by weight of the agent Tinuvin 99-2, 0.2 parts by weight of diethylene glycol, 10 parts by weight of hexadecyl 2-ethylhexanoate as a plasticizer, 1-ethyl-3-methylimidazolium bis(fluoromethanesulfonyl) as an antistatic agent ) 1.5 parts by weight of imide and 0.05 parts by weight of F-571 manufactured by DIC as a leveling agent are mixed and dispersed. A urethane coating film was prepared by coating a PET substrate with a thickness of 80 μm or less and drying at 130° C. for 5 minutes. The viscosity of the composition containing the urethane prepolymer (E) of any example was in the range of 1 to 100 Pa·s, and the residual liquid of the composition after sheet preparation showed good fluidity even after 24 hours. . The resulting urethane cured product had good wettability, high strength, and high transparency, and could be suitably used for sealants, paints, pressure-sensitive adhesives, adhesives, and the like.

As described above in the Examples, the urethane prepolymer (E) in the present invention is a highly transparent urethane prepolymer that does not contain gels or precipitates and has excellent curability. By using it, it is possible to stably form a highly transparent, high-strength, light-releasable urethane coating film with less surface tack.

By taking advantage of its characteristics, it was shown that the polyurethane obtained using the urethane prepolymer (E) can be suitably used for sealants, paints, adhesives, adhesives, etc.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

In addition, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-072434 filed on April 22, 2021 are cited here and incorporated as disclosure of the specification of the present invention. It is a thing.

Claims

Having an alkylene oxide residue having 3 or more carbon atoms, an aromatic amine residue and a polyisocyanate residue, and having a polyalkylene oxide structure having an aromatic amine residue locally at the molecular end, an active hydrogen group-terminated Urethane prepolymer (E).
A reaction product of an NCO-terminated prepolymer (D), which is a reaction product of a polyalkylene oxide (A) and a polyisocyanate (C), and a polyalkylene oxide (B) having an aromatic amine residue and two or more hydroxyl groups The urethane prepolymer (E) according to claim 1, wherein
The urethane prepolymer (E) according to claim 1 or claim 2, containing 5 to 70% by weight of polyol structures having aromatic amine residues or residues thereof.
As aromatic amine residues, one or more residues selected from the group consisting of 4,4′-diphenylmethanediamine residues, 2,4-tolylenediamine residues and 2,6-tolylenediamine residues. The urethane prepolymer (E) according to any one of claims 1 to 3, comprising:
Any one of claims 1 to 4, wherein the polyisocyanate residue contains one or more residues selected from the group consisting of aliphatic isocyanate residues, alicyclic isocyanate residues and modified residues thereof. The urethane prepolymer (E) described in .
The polyol structure having an aromatic amine residue at the molecular end contains a polyalkylene oxide residue, and the polyalkylene oxide residue is selected from the group consisting of a polypropylene oxide residue, a polypropylene-ethylene oxide residue and a polyethylene oxide residue. 6. The urethane prepolymer (E) according to any one of claims 1 to 5, comprising one or more types of residues.
A urethane prepolymer composition solution containing the urethane prepolymer (E) according to any one of claims 1 to 6, an organic solvent and an additive,
A urethane prepolymer composition solution, wherein the concentration of the urethane prepolymer (E) in the urethane prepolymer composition solution is 60% by weight or more and 99% by weight or less.
A urethane-forming composition comprising the urethane prepolymer (E) according to any one of claims 1 to 6 and an isocyanate compound (F).
A urethane-forming composition solution containing the urethane prepolymer composition solution according to claim 7 and an isocyanate compound (F).
A cured urethane product containing the urethane-forming composition according to claim 8 or a reaction product of the urethane-forming composition in the urethane-forming composition solution according to claim 9.
A polyurethane sheet made of the cured urethane material according to claim 10.