JP2022166969A - Urethane prepolymer composition solution - Google Patents

Abstract

To provide a highly transparent urethane prepolymer composition solution having moderate coloration and good visibility which contributes to rapid formation of a cured urethane material having high strength with good curability, and to provide a highly transparent cured urethane material having good appearance, moderate coloration and high visibility.SOLUTION: There is provided a urethane prepolymer composition solution which comprises an NCO group-terminated urethane prepolymer (D), a urethanization catalyst comprising a metal component, and a glycol ether solvent having an SP value of 8.0 or more, wherein the urethane prepolymer (D) is at least a reaction product of a polyol (A) and a polyisocyanate (C), a content of the glycol ether solvent having an SP value of 8.0 or more in the urethane prepolymer composition solution is in a range of 0.1 to 20 wt.%, a concentration of the urethane prepolymer (D) is 75 wt.% to 99.9 wt.% and the urethane prepolymer composition solution has a Gardner color number of 2 to 13.SELECTED DRAWING: None

Description

The present disclosure relates to urethane prepolymer composition solutions.

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.

Further, polyurethanes obtained from polyalkylene oxides containing a large amount of unsaturated monools are unlikely to have a high molecular weight, low tensile elongation at break, and 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, the polyurethane-forming composition described in Patent Document 1 and the urethane prepolymer using the same exhibit high strength and use a large amount of highly colored aromatic amine polyol. In some cases, the coloring was too strong, and the visibility of insoluble matter and residue was not sufficient.

Further, Patent Document 2 describes a urethane-forming composition containing a polyalkylene oxide and polytetramethylene glycol with less unsaturated monools, a polyalkylene oxide having one hydroxyl group and an ethylene oxide residue, and a urethane prepolymer using the same. By using a urethane-forming composition containing, it is disclosed that a polyurethane having good coatability and productivity and high tensile strength can be obtained. On the other hand, the polyurethane-forming composition described in Patent Document 2 and the urethane prepolymer using it use a large amount of polytetramethylene glycol in order to develop high strength, but the resulting composition is colorless. However, there was a problem with the visibility of the coating film, such as the smoothness of the coated surface.

Therefore, the urethane prepolymer composition is a highly transparent urethane prepolymer composition solution having moderate coloring and good visibility, and capable of forming a highly transparent urethane cured product with good appearance, high transparency, and high strength. solution was sought.

JP 2020-158551 A Japanese Patent Application Laid-Open No. 2020-76011

A highly transparent urethane prepolymer composition solution that has moderate coloring and good visibility for insoluble matter and residue, and the resulting urethane cured product has moderate coloring, good visibility, and good appearance. To provide a urethane prepolymer composition solution that contributes to the rapid formation of a highly transparent urethane cured product with high strength.

Each aspect is [1] to [6] shown below.
[1] A urethane prepolymer composition solution containing an NCO group-terminated urethane prepolymer (D), a urethanization catalyst containing a metal component, and a glycol ether solvent having an sp value of 8.0 or more,
The urethane prepolymer (D) is a reaction product of at least polyol (A) and polyisocyanate (C),
The content of the glycol ether solvent having an sp value of 8.0 or more in the urethane prepolymer composition solution is in the range of 0.1 to 20% by weight, and the concentration of the urethane prepolymer (D) is 75% by weight or more. 9% by weight or less,
The Gardner color number of the urethane prepolymer composition solution is in the range of 2 or more and 13 or less,
Urethane prepolymer composition solution.
[2] The molar ratio (NCO/OH ratio) of the sum of the hydroxyl groups of the polyol (A) forming the urethane prepolymer (D) and the sum of the NCO groups of the polyisocyanate is in the range of 1.30 to 5.00. The urethane prepolymer composition solution according to [1].
[3] The urethane prepolymer composition solution according to [1] or [2], wherein the urethane prepolymer composition solution has a viscosity of 0.1 to 30 Pa·s at 70°C.
[4] Described in [1] to [3], wherein the content of the urethanization catalyst containing a metal component is in the range of 0.001 to 0.05 parts by weight with respect to 100 parts by weight of the urethane prepolymer (D). of the urethane prepolymer composition solution.
[5] A cured polyurethane product obtained by using the urethane prepolymer composition solution described in [1] to [4].
[6] A polyurethane sheet made of the cured urethane product of [5].

Highly transparent and moderately colored, providing good visibility for insoluble matter and residue. A urethane prepolymer composition solution that contributes to rapid formation of a cured urethane product can be provided.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS Illustrative modes for carrying out the invention are set forth in detail below.

A urethane prepolymer composition solution according to one embodiment is a urethane prepolymer composition solution containing an NCO group-terminated urethane prepolymer (D), a urethanization catalyst containing a metal component, and a glycol ether solvent having an sp value of 8.0 or more. and
The urethane prepolymer (D) is a reaction product of at least polyol (A) and polyisocyanate (C),
The content of the glycol ether solvent having an sp value of 8.0 or more in the urethane prepolymer composition solution is in the range of 0.1 to 20% by weight, and the concentration of the urethane prepolymer (D) is 75% by weight or more. 9% by weight or less,
The Gardner color number of the urethane prepolymer composition solution is in the range of 2 or more and 13 or less,
It relates to a urethane prepolymer composition solution.

<Urethane prepolymer (D)>
The urethane prepolymer (D) contained as an essential component in the urethane prepolymer composition solution is characterized by being a reaction product of at least polyol (A) and polyisocyanate (C) and having an NCO group terminal. In forming the urethane prepolymer (D), a urethanization catalyst, solvent, plasticizer, leveling agent, and other additives may be added as necessary.

The molar ratio (NCO/OH ratio) of the sum of the hydroxyl groups of the polyol forming the NCO-terminated urethane prepolymer (D) and the sum of the NCO groups of the polyisocyanate is not particularly limited, but is from 1.30 to 5.00. A range is preferred. By mixing in an amount ratio in which the NCO/OH ratio is in the range 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, mainly the structure in which the polyol (A) and the polyisocyanate (C) reacted at a molar ratio of 1:2, the chain-reacted high molecular weight and free (Unreacted) polyisocyanate (C) is less likely to be contained, and the transparency of the resulting urethane cured product tends to be remarkably good. The NCO group ratio (NCO/OH ratio) is preferably in the range of 1.60 to 4.40, 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 polyalkylene oxide (B) having a rigid structure such as a small amount of aromatic amine residue or sucrose residue, free (unreacted) polyisocyanate (C) can be reduced, and the urethane cured product and active hydrogen group-terminated urethane prepolymers, chain reactions are easily suppressed, and the obtained urethane cured product tends to exhibit high transparency. In addition, by using a small amount of one or more monools (AC) selected from the group consisting of polyoxyalkylene glycol monoalkyl ethers, polyoxyalkylene glycol monoalkenyl ethers, and polyoxyalkylene glycol monophenyl ethers, free (not It is preferable because the amount of the polyisocyanate (C) in the reaction) can be reduced, and the coatability when coating with a coating machine or the like is particularly excellent.

It is preferable not to use a silicone component (monool, polyol, polyamine) having a reactive group or a fluorine component having a reactive group. It is preferable because it is likely to be incorporated into a chain and less likely to cause deterioration in staining properties.

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 content of the residue of the polyol (A) contained in the urethane prepolymer (D) is not particularly limited, but it should be 30% by weight or more and 99% by weight or less in order to easily exhibit good coatability and high transparency. More preferably, the content is in the range of 50% by weight or more and 95% by weight or less, and 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. 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 content of the residue of the polyisocyanate (C) contained in the urethane prepolymer (D) is not particularly limited. Preferably, 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, because it is easy to achieve both higher transparency and high strength. 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.

When forming the urethane prepolymer (D), in addition to the polyol (A), a polyalkylene oxide (B) having a rigid structure such as an aromatic amine residue or a sucrose residue and a monool (AC) are added. When added, the total amount of residues of polyalkylene oxide (B) and other monools (AC) is preferably in the range of 30% by weight or less. Among them, the content is preferably 0.1 to 20% by weight or less, and 0.5 to 15% by weight, because the handling property is good, the transparency is easy to express, and the strength is easy to express. A range is more preferred, and a range of 0.5 to 8% by weight is most preferred.

In addition, since the coloration tends to be strong and the visibility in the urethane prepolymer composition solution tends to deteriorate, the polyalkylene oxide (B) residue having a rigid structure such as an aromatic amine residue or a sucrose residue is It is preferably 10% by weight or less.

The urethane prepolymer (D) contains residues of the polyol (A), residues of the polyisocyanate (C), residues of the exemplified polyalkylene oxide (B) and residues of the monool (AC), as well as other Although it is not particularly limited, the residue is preferably 5% by weight or less because compatibility is deteriorated and viscosity increases, transparency is easily reduced and handling property is deteriorated.

The urethane prepolymer (D) may contain a monool structure having an unsaturated group in the polyol used, and may contain an unsaturated group which is the residue thereof, but is not particularly limited, depending on the raw material used. Although different, the unsaturated group content is preferably in the range of 0.0001 meq/g to 100 meq/g because it tends to exhibit higher curability. 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 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.

<Polyol (A)>
The polyol (A) used in the urethane prepolymer (D) is not particularly limited, but examples include polycarbonate polyol, polytetramethylene glycol, polyolefin polyol, acrylic polyol, polyester polyol, Mannich polyol, and aliphatic polyamine. Commercially available polyols such as polyols, polyethylene glycols, polycaprolactone polyols, fluorinated polyols, silicone-containing polyols, phosphorus-based polyols, polyalkylene oxides, and mixtures of two or more thereof.

Among these, polytetramethylene glycol, polyester polyols, aliphatic polyamine polyols, polyalkylene oxides are used in order to easily obtain a urethane-forming composition having excellent productivity, high transparency, moderate viscosity, and good handling properties. , and mixtures of two or more thereof.

The number average molecular weight of the polyol (A) is not particularly limited, but it is preferably 2000 or more because it has an appropriate viscosity, is excellent in handleability, and tends to have good coatability and wettability. Among them, the polyol (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 polyol (A) is calculated from the hydroxyl value of polyol (A) calculated by the method described in JIS K-1557-1 and the number of hydroxyl groups in one molecule of polyol (A). can be done. The hydroxyl value (mgKOH/g) of the polyol (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 polyol (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. . If the viscosity of the polyol (A) at 25° C. is 100 mPa·s or more and 200,000 mPa·s or less, it is preferable because it is easy to coat 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 polyol (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 raw materials for obtaining the polyol (A) are readily available and the resulting polyol (A) has a high industrial value. More preferably, it contains 50% by weight or more of a polyalkylene oxide having an alkylene oxide residue with 3 or more carbon atoms.

Moreover, the polyol (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. 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 polyol (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 polyol (A) is not particularly limited, but it preferably has two or more hydroxyl groups in one molecule, more preferably two to six hydroxyl groups, and most preferably one molecule. has 2 or more and 3 or less hydroxyl groups. When the number of hydroxyl groups in one molecule of the polyol (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.

The ratio of primary hydroxyl groups in the polyol (A) is not particularly limited, but 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 polyol (A) is preferably liquid at room temperature because it facilitates the production of the urethane prepolymer (D).

The degree of unsaturation of the polyol (A) is not particularly limited because it is easy to make the prepolymer or urethane cured product highly transparent regardless of the use of a polyol with less unsaturated monools, but polyalkylene oxide having an aromatic amine residue Since it is likely to require an increased amount of polyfunctional polyol such as (B) and a large amount of polyol having a more rigid skeleton than polypropylene oxide, even if it is bifunctional, it is preferably 0.010 meq/g or less, more preferably 0.007 meq/g. g or less, most preferably 0.004 meq/g or less. Such polyol (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 polyol (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 distribution of the prepolymer is It is preferably 1.059 or less, more preferably 1.039 or less, and most preferably 1.004 to 1.029 or less, because it tends to be narrow and tends to be excellent in handleability.

The polyol (A) preferably has a water content of 2,000 ppm or less.

The polyalkylene oxide (B) having a rigid structure that is preferably used in a small amount in the urethane prepolymer (D) is not particularly limited, but examples include sorbitol polyol, sucrose polyol, aromatic amine polyol, or A mixture of two or more of these can be mentioned and preferably used.

The monool (AC) preferably used in a small amount in the urethane prepolymer (D) is not particularly limited, but examples include polyoxyalkylene glycol monoalkyl ether, polyoxyalkylene glycol monoalkenyl ether, polyoxyalkylene It is preferably one or more selected from the group consisting of glycol monophenyl ether. Among them, it tends to be excellent in coatability, and while maintaining high transparency, the obtained urethane tends to have low staining resistance and low tackiness. Therefore, polyoxyethylene glycol monomethyl ether having a molecular weight of 250 or more and 1300 or less is preferable.

<Polyisocyanate (C)>
The polyisocyanate (C) used in the urethane prepolymer (D) is not particularly limited, but examples thereof include the polyisocyanates exemplified below. diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, 1,6-hexamethylene diisocyanate, 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 reaction of these with polyols and monools and a mixture 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, in order to easily obtain a urethane-forming composition with excellent productivity and high transparency and little coloration, as the polyisocyanate (C), an aliphatic isocyanate, an alicyclic isocyanate, or a modified product thereof, or preferably contains a mixture of two or more of

Such polyisocyanate (C) is not particularly limited, but includes, for example, the following exemplified polyisocyanates (C), 1,6-hexamethylene diisocyanate, isophorone diisocyanate, aliphatic isocyanate-containing prepolymers, Prepolymers containing cycloaliphatic isocyanates or containing urethane, carbodiimide, allophanate, urea, biuret, isocyanurate, amide, imide, uretonimine, uretdione or oxazolidone groups of these isocyanates Modified products are more preferred. These isocyanates may be contained singly or as a mixture of two or more.

Among them, 1,6-hexamethylene diisocyanate and modified products thereof are preferably contained because the viscosity of the urethane prepolymer does not increase with time 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 isophorone diisocyanate because the transparency of the urethane cured product obtained using is likely 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.

<Urethane catalyst containing metal component>
The urethane prepolymer composition solution contains a urethanization catalyst containing a metal component as an essential component. When adjusting the number of Gardner colors in the range of 2 to 13 to improve visibility without including a urethanization catalyst containing a metal component, it is difficult to achieve both rapid formation (curability) and visibility of the urethane cured product. becomes difficult to use.

Among them, it is easy to efficiently form the NCO-terminated urethane prepolymer (D), has few side reactions, and is easy to obtain a urethane prepolymer composition and a urethane cured product having higher transparency and moderate coloring. The content of the urethanization catalyst containing a metal component is preferably in the range of 0.001 to 0.05 parts by weight with respect to 100 parts by weight of the urethane prepolymer (D), more preferably urethane containing a metal component. The conversion catalyst ranges from 0.003 to 0.045 parts by weight, most preferably from 0.005 to 0.03 parts by weight.

The urethanization catalyst containing a metal component is not particularly limited as long as it is a compound that contains a metal component and exhibits urethanization activity. Even if a retarder such as acetylacetone is added at the time of mixing, the pot life tends to be shortened. Therefore, an organometallic compound containing at least one metal selected from Fe, Zr, Ti, and Al is preferable. Among them, one or more of metal chelate catalysts such as Fe chelate catalysts, Zr chelate catalysts, Ti chelate catalysts, Al chelate catalysts, which have moderate coloring and catalytic activity and are easy to adjust the degree of coloring and reactivity. More preferably, the Fe chelate catalyst alone is used because it provides appropriate coloring to easily improve visibility and exhibits good catalytic activity to facilitate rapid curing.

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

<Glycol ether solvent>
The urethane prepolymer composition solution contains a glycol ether solvent with an sp value of 8.0 or more as an essential component, and the content of the glycol ether solvent with an sp value of 8.0 or more in the urethane prepolymer composition solution. is in the range of 0.1 to 20% by weight, and the concentration of the urethane prepolymer (D) is 75% by weight or more and 99.9% by weight or less. Note that the sp value refers to a value calculated by the Fedors method obtained from the cohesive energy and molar molecular volume of each atomic group (Reference: "Paint Research, No. 152, October 2010"). In the Fedors method, the sp value is defined as the square root of the cohesive energy density. Specifically, the sp value is defined by the following formula.

δ=(ΔE/V) ^1/2
In the above formula, δ is the sp value ((cal/cm ³ ) ^1/2 ), ΔE is the cohesive energy (cal/mol), and V is the molar volume of the solvent (cm ³ /mol).

In the Fedors method, both the cohesive energy and the molar molecular volume are considered to depend on the type and number of substituents contained in the solvent. Therefore, the cohesive energy is calculated from the cohesive energy and molecular volume of each substituent, taking into consideration the number of substituents.

The urethane prepolymer composition solution contains a glycol ether solvent with an sp value of 8.0 or more, and the content of the glycol ether solvent with an sp value of 8.0 or more in the urethane prepolymer composition solution is 0.1. ~20% by weight, and the concentration of the urethane prepolymer (D) is 75% by weight or more and 99.9% by weight or less, so that even if a urethanization catalyst containing a metal component is used, it can be contained in the system during drying and curing. It is possible to stably suppress curing shrinkage that tends to occur during reaction curing due to a longer period of retention and compatibility, and to form urethane with good moldability and wrinkle-free appearance, resulting in high solidity. If the glycol ether solvent with an sp value of 8.0 or more per minute is less than 0.1% by weight, wrinkles may occur when the Gardner color number is adjusted to a range of 2 or more and 13 or less in order to improve visibility with a high solid content. is likely to occur, and the coating film becomes cloudy, making it difficult to stably obtain a cured urethane product with a good appearance. In addition, when the content of the glycol ether solvent having an sp value of 8.0 or more in the urethane prepolymer composition solution exceeds 20% by weight, the glycol ether solvent tends to remain in the urethane cured product during drying and curing, resulting in poor curability. It is difficult to use due to the fear of bleed contamination as well as reduced strength.

The content of the glycol ether solvent having an sp value of 8.0 or more in the urethane prepolymer composition solution is not particularly limited as long as it is in the range of 0.1 to 20% by weight. 0.5 to 15% by weight because the period during which the solubility is retained becomes longer, and the curing shrinkage that tends to occur during reaction curing is more stably suppressed, and the physical properties are less likely to deteriorate due to remaining in the urethane cured product. is preferably in the range of , more preferably in the range of 1.0 to 10% by weight, and most preferably in the range of 3.0 to 8.0% by weight.

The structure of the glycol ether-based solvent is not particularly limited as long as the sp value is 8.0 or more, and can include any terminal structure and any glycol ether structure. It is preferable not to contain an active hydrogen group such as a hydroxyl group or an amino group because the transparency tends to be deteriorated by being incorporated as a 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). Most preferably included. Furthermore, by using ethyl acetate, toluene, and methyl ethyl ketone in combination, the moldability can be easily adjusted.

<Urethane prepolymer composition solution>
The urethane prepolymer composition solution contains, as essential components, an NCO group-terminated urethane prepolymer (D), a urethanization catalyst containing a metal component, and a glycol ether solvent having an sp value of 8.0 or more. Gardner color number is in the range of 2 or more and 13 or less.

When the Gardner color number of the urethane prepolymer composition solution is less than 2, the visibility of the remaining liquid amount of the urethane prepolymer composition solution is poor, and rapid solution management and rapid detection of insoluble matter and deposits in the solution. However, it is difficult to use because it is difficult to quickly evaluate the smoothness of the coating film because the resulting urethane coating film and urethane cured product do not have an appropriate coloration, and the Gardner color number is less than 13. If it exceeds, the coloration is too strong and the visibility in the solution is lowered, so that it is difficult to quickly detect the residue, which makes it difficult to use.

Furthermore, if the urethane prepolymer composition solution contains a urethanization catalyst (Bi, Sn, etc.) containing a metal component with low coloring and the Gardner color number of the urethane prepolymer composition solution is less than 2, it is necessary to contain a coloring component, but it deteriorates the physical properties of the urethane. Even if a reaction retarder such as acetylacetone is added, the pot life after mixing with the isocyanate cross-linking agent will not be long, depending on the amount of catalyst used. is.

In addition, when the Gardner color number is adjusted to the range of 2 or more and 13 or less by using a large amount of highly colored polyol or amine catalyst without containing a urethanization catalyst containing a metal component, visibility is good with moderate coloring. However, it is difficult to use because the transparency tends to deteriorate due to side reactions caused by moisture and the like, and the curability is insufficient to stably obtain a high-strength urethane cured product.

Among them, the visibility of the urethane prepolymer composition solution is better, and the visibility of the resulting urethane coating film is likely to be better, so the Gardner color number is preferably in the range of 2 to 10, and more preferably. is in the range of 3 to 8, most preferably in the range of 4 to 7. When the Gardner color number of the urethane prepolymer composition solution is within the above range, the visibility of the composition solution is improved with appropriate coloring, and the degree of coloring of the urethane coating immediately after coating affects the appearance and smoothness of the coating surface. Gender can be determined quickly. Therefore, the insoluble matter and residue in the urethane prepolymer composition solution can be determined more quickly, and the visibility of the coated surface is also improved.

The concentration of the urethane prepolymer (D) in the urethane prepolymer composition solution is not particularly limited as long as it is 75% by weight or more and 99.9% by weight or less. Since it is easy to handle and has good handling properties, it is easy to achieve both visibility and handling properties. It is in the range of 96% by weight. If the concentration of the urethane prepolymer (D) is less than 75% by weight, a large amount of solvent is used, which worsens economic efficiency, and it is difficult to form a thick and uniform coating film due to a decrease in viscosity and an increase in elasticity of the liquid. Therefore, it becomes difficult to use.

In the formation of the urethane prepolymer (D), other urethanization catalysts, other solvents, plasticizers, leveling agents, and other additives may be added as necessary, and these may remain in the urethane prepolymer composition solution. may contain Although not particularly limited, the urethane prepolymer composition solution may contain coloring components other than polyols, polyisocyanates, urethanization catalysts containing metal components, and triazole derivatives, but there is concern about bleeding. It is preferably not contained, and if it is contained, the amount added is preferably 10% by weight or less, more preferably 3% by weight or less.

The urethane prepolymer composition solution has better handling properties, mainly during reactions including curing, such as the formation of hydroxyl-terminated urethane prepolymers with excellent storage stability and excellent moldability due to less liquid flow during curing reactions. The viscosity at 70° C. is preferably in the range of 0.1 to 30 Pa·s, more preferably in the range of 0.3 to 20 Pa·s.

The urethane prepolymer composition solution is not particularly limited, but preferably has a viscosity of 1 to 100 Pa·s at 25° C. and a transparent liquid appearance (haze of 15% or less at a thickness of 1 cm). Among them, the preferable properties are that additives can be easily mixed, the mixing of the cross-linking agent and the handling of coating are excellent, and the cured urethane product tends to be stably highly transparent. 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 composition solution is not particularly limited. % or less.

The urethane prepolymer composition solution 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.

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, when the polyalkylene oxide (B) is used, it becomes easier to suppress the catalytic activity derived from the amine structure, which extends the pot life and suppresses rapid gelation during drying, aging, and coating. It preferably contains an acid retardant because it stably 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 retardant 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 (D). is in the range of In addition, the pH of the urethane prepolymer (D) 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 (D) 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.

The keto-enol tautomeric compound is not particularly limited, but is preferably one or more of ethyl acetoacetate and acetylacetone, since the catalyst activity is more easily adjusted to 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. It is preferably 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 (D). is more preferably in the range of 0.2 to 2 parts by weight, 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 stabilizers include, but are not limited to, isocyanates and compounds that suppress the reactivity of 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.

When the stabilizer 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 (D). 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 step of these additives may be carried out at room temperature because the weight change due to volatilization is small, or may be carried out with heating in order 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.

The NCO group-terminated urethane prepolymer composition solution may be reacted with a polyol cross-linking agent, a polyamine cross-linking agent, a cross-linking agent having an active hydrogen group such as moisture in the air, or a curing agent to form a cured urethane product directly. In addition, by utilizing the reactivity of the NCO group, various excess active hydrogen compounds such as polyols and polyamines are added to the end to prevent gelation, thereby enhancing storage stability. may be reacted with to form a urethane cured product.

<Method for producing cured urethane and urethane coating>
The NCO group-terminated urethane prepolymer composition solution and the active hydrogen group-terminated urethane prepolymer composition solution obtained using the same are reacted by various methods and cured (solidified) to produce a cured urethane product. can do. The method for producing the cured urethane product is not particularly limited. , In the presence of urethanization catalysts, solvents, antioxidants, light stabilizers, chain extenders, cross-linking agents, other additives, etc., at room temperature or at a high temperature of 150 ° C or less, urethanization reaction, urea formation reaction, if necessary It can be manufactured by proceeding with drying.

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 (D) composition solution and the excessive polyalkylene oxide (B) having a rigid structure to form an active hydrogen group-terminated urethane prepolymer composition solution, agent and an isocyanate cross-linking agent (F), a step of coating a substrate with a thickness of 10 to 500 μm, and a step of drying and curing at 70 to 160 ° C. for 30 seconds to 10 minutes. , is preferable because a urethane coating film with high transparency and low tackiness can be produced with high productivity. 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, the urethane prepolymer (D) has a moderate degree of coloration, has remarkably good visibility, does not flow easily even at high temperatures, and cures quickly with little thickness unevenness. It is preferable to dry and cure in the range of 120 to 145° C. for 2 to 6 minutes, more preferably in the range of 2 to 6 minutes, 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, polyurethanes are particularly preferably used as sealants, paints, pressure-sensitive adhesives, and adhesives because they are strongly required to have mechanical properties and tackiness/adhesive properties, and are required to have workability and coatability.

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) Polyol (A) used in Examples and Comparative Examples, or other monool (AC)
(Raw material 1-1) Polyol (A) used in Examples and Comparative Examples
The polyol (A1) uses an imino group-containing phosphazenium salt (hereinafter referred to as an IPZ catalyst) and triisopropoxyaluminum in combination to sufficiently perform dehydration and solvent removal to obtain a bifunctional polyoxypropylene glycol having a molecular weight of 400. was obtained by addition of sufficiently dehydrated propylene oxide. (A1) is a polyoxypropylene glycol (diol) having only a propylene oxide group as an alkylene oxide group and two hydroxyl groups in one molecule.

Polyol (A2) uses an IPZ catalyst and triisopropoxyaluminum in combination in the same manner as (A1), and after adding a propylene oxide group as an alkylene oxide group to polyoxypropylene triol having a molecular weight of 600, propylene remaining in the system It is a polyoxyalkylene triol with a low degree of unsaturation containing primary hydroxyl groups, which is obtained by adding ethylene oxide in blocks after removing the oxide.

Polyol (A3) used NIPPOLAN 5711 manufactured by Tosoh, which is a commercially available polyester polyol.

All the polyols (A1) to (A3) used in the examples were used after heating and vacuum dehydration. Polyol (A) produced using an IPZ catalyst was used after removing the catalyst including aluminum.
(Raw material 1-2) Monool (AC) used in Examples and Comparative Examples
Monool (AC1) is a polyethylene glycol monomethyl ether, which has a methyl group at one end and consists of one hydroxyl group and an ethylene oxide group in one molecule.

Table 1 shows the properties of polyols (A1) to (A3) and monool (AC1).

(Raw material 2) Polyalkylene oxide (B)
(Raw materials 2-1) Polyalkylene oxides (B1) and (B2) used in the examples
Polyalkylene oxide (B1) is a commercially available tolylenediamine-based polypropylene glycol, and NJ-410HN manufactured by Ningwu Kako with a hydroxyl value of 340 mgKOH/g was used. Calculated from these properties, the polyol has a molecular weight of 660, an aromatic amine residue content of 19%, and is colored.

The polyalkylene oxide (B2) is a commercially available sucrose-based polypropylene glycol, and Toho Polyol O-855W manufactured by Toho Chemical Industry Co., Ltd. having a nominal functional group number of 8.0 and a hydroxyl value of 377 mgKOH/g was used. The molecular weight calculated from this property is 1190, the sucrose residue content is 29%, and the polyol is colored.
(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), and Neostan U-810, manufactured by Nitto Kasei Co., Ltd., which is octyltin dilaurate (DOTDL), were 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 TEGD) manufactured by Toho Chemical Industry Co., Ltd. were used as solvents.

In Comparative Examples, dipropylene glycol dimethyl ether (abbreviated as DPGD, sp value 7.9, boiling point 175° C.) manufactured by Nippon Nyukazai Co., Ltd. was used.

(Production example of urethane prepolymer composition solution)
Polyol (A), which is a raw material for urethane prepolymer (D), and optionally added polyalkylene oxide (B) and monool (AC) are added to a four-neck eggplant flask and heated at 100° C. for 1 hour or more. Vacuum dehydration was performed to remove moisture.

After that, the mixture was cooled to 50° C. or less, and the solvent, isocyanate, and catalyst masterbatch were added, and then the temperature was raised to a predetermined temperature. 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 ) was obtained.

(Evaluation items of urethane prepolymer composition solution)
<Transparency>
The transparency of the urethane prepolymer composition solution 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%.

<Liquid Visibility>
The urethane prepolymer composition solution was transferred to a glass container, and visibility was evaluated according to the following criteria.

⊚ (acceptable): Appropriate coloring allows the amount of remaining liquid to be determined at a glance, and foreign matter in the solution in the 0.5 L medium bottle (8.6 cmφ) can be detected quickly.

Good (acceptable): Coloring is strong, but foreign matter in the solution in the 0.5 L medium bottle (8.6 cmφ) can be detected, and the remaining liquid amount can be determined at a glance.

Δ (failure): The coloring is too strong, and the amount of remaining liquid can be determined at a glance, but it is difficult to visually detect foreign matter in the solution in the 0.5 L medium bottle (8.6 cmφ).

× (failed): Colorless and insufficiently visible (judging that the amount of residual liquid cannot be determined at a glance)

<Curability>
To the NCO group-terminated urethane prepolymer composition solution, the polyalkylene oxide (B1) is added at a ratio of 30 parts by weight with respect to 100 parts by weight of the urethane prepolymer (D) and reacted to form active hydrogen with high storage stability. Forms terminal urethane prepolymer. 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 to determine whether the urethane prepolymer contributed to the formation of a cured urethane product with high strength.

⊚ (accepted): tack disappeared and remarkably high strength and easy peelability can be expected.

◯ (accepted): Slight tack, and remarkably high strength and easy peelability can be expected.

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

In addition, the visibility and appearance of the urethane sheet having the urethane cured product layer obtained by the above curability evaluation were evaluated according to the following criteria.

<Visibility and Appearance of Cured Urethane Layer>
⊚ (Pass): The presence or absence of the coating film can be seen at a glance, the smoothness of the urethane coating film can be quickly determined by the shade of color tone, and the appearance is good with no wrinkles or white turbidity.

○ (acceptable): The urethane coating film has a light coloration, and the smoothness can be judged.

△ (unacceptable): Visibility is good, but the appearance is poor due to wrinkles and cloudiness × (unacceptable): Almost colorless without moderate coloring, visual recognition of the coating film such as smoothness of the coated surface less sexual

The above-mentioned transparency, liquid visibility, curability, visibility of the urethane cured product layer, and appearance all pass, and a highly transparent urethane resin that has moderate coloring, good visibility for insoluble matter and residue, and high transparency. Determined to be a urethane prepolymer composition solution that contributes to the rapid formation of a cured urethane product of good appearance and high strength, with the resulting urethane cured product having moderate coloring and good visibility. and passed.

<Example>
(Example 1)
According to the production example of the urethane prepolymer composition solution and the composition ratio described in Example 1 in Table 1, 100 parts by weight of polyol (A1) was added for dehydration, and triethylene glycol dimethyl ether was used as a glycol ether solvent for the final pretreatment. Prepared so that the polymer concentration was 95%, the isocyanate compound (C1) and 0.025 parts by weight of iron trisacetylacetonate as a urethanization catalyst were mixed with the amount (M _OH ) of hydroxyl groups derived from (A1) and (C1). The amount of isocyanate groups (M _NCO ) derived from is charged so that the molar ratio of M _NCO of (C1) / M _OH of (A1) = 2.75, and reacted at a constant temperature of 70 ° C. for 3 hours. Thus, a urethane prepolymer composition solution containing the NCO group-terminated urethane prepolymer (D1) was obtained. Table 2 shows the results of Example 1. The composition solution containing the urethane prepolymer (D1) was highly transparent with no gel or precipitate, had a moderate coloration with a Gardner color number of 4, and was free from turbidity, thus exhibiting good visibility of the solution. Further, the initial curability was remarkably good, and remarkably high strength could be expected, and the coating film of the cured urethane was also highly transparent, moderately colored, and remarkably good in visibility.
(Examples 2-4)
According to the composition ratios described in the examples in Table 2, a small amount of colored polyalkylene oxide (B1) having a rigid aromatic amine residue was used in addition to polyol (A1), polyol (A), polyalkylene oxide (B) and polyisocyanate (C) were produced by changing the charging ratio. Table 2 shows the results of Examples 2-4. As the content of the polyalkylene oxide (B1) increased, the visibility decreased very slightly, but in the range of 15 parts by weight or less, the composition solution containing the NCO group-terminated urethane prepolymer (D) was a gel-like product. It was remarkably highly transparent with no sediment or deposits, and had moderate coloration, all of which showed good visibility of the solution. In addition, both of them have good initial curability and can be expected to have significantly higher strength. In the range of 15 parts by weight or less, all of them were highly transparent, moderately colored, and had good visibility.
(Example 5)
According to the composition ratio described in Example 5 in Table 2, the polyol (A1) of Example 1 was changed to a polyol (A2) having a trifunctional ethylene oxide residue. Table 2 shows the results of Example 5. The composition solution containing the urethane prepolymer (D5) was highly transparent with no gel or precipitate, had a moderate coloration with a Gardner color number of 4, and was free from turbidity, thus exhibiting good visibility of the solution. Further, the initial curability was remarkably good, and remarkably high strength could be expected, and the coating film of the cured urethane was also highly transparent, moderately colored, and remarkably good in visibility.
(Example 6)
It was produced by changing the polyol (A1) of Example 1 to polyol (A3) according to the composition ratio described in Example 6 in Table 2. Table 2 shows the results of Example 6. The composition solution containing the urethane prepolymer (D6) was highly transparent with no gel or precipitate, had a moderate coloration with a Gardner color number of 4, and was free from turbidity, thus exhibiting good visibility of the solution. In addition, the initial curability is remarkably good, and remarkably high strength can be expected. Although the coating film of the cured urethane material was slightly cloudy, it was highly transparent and usable, and had moderate coloring. and visibility was good.
(Examples 7-9)
Compared to Example 1, it was produced by adjusting the Gardner color number by changing the content of iron trisacetylacetonato, which is a urethanization catalyst containing a metal component and has coloring properties. Table 2 shows the results of Examples 7-9. The composition solution containing the urethane prepolymer (D) is highly transparent with no gels or precipitates. Although it decreased, it showed high visibility in the usable range, and if the amount of urethanization catalyst containing a metal component was small, the curability decreased very slightly, but it exhibited good curability in the usable range. Both high solution visibility and good curability can be expected, and remarkably high strength can be expected. It was something.
(Examples 10 and 11)
According to the composition ratios described in the examples in Table 2, a small amount of a polyalkylene oxide (B2) having a rigid sucrose residue and having a coloring is used in Example 5, and the polyol (A) and the polyalkylene oxide (B) and polyisocyanate (C) were produced by changing the charging ratio. Table 2 shows the results of Examples 10 and 11. The composition solution containing the urethane prepolymer (D) was highly transparent with no gel or precipitate, had a moderate coloration with a Gardner color number of 5, and was free from turbidity, thus exhibiting good visibility of the solution. Further, the initial curability was remarkably good, and remarkably high strength could be expected, and the coating film of the cured urethane was also highly transparent, moderately colored, and remarkably good in visibility.
(Example 12)
According to the composition ratio described in Example 12 in Table 2, a monool (AC1) which is a monol having a methyl group at one end and having one hydroxyl group and an ethylene oxide group in one molecule, in contrast to Example 2 It is manufactured using a small amount of Table 2 shows the results of Example 12. The composition solution containing the urethane prepolymer (D) was highly transparent with no gel or precipitate, had a moderate coloration with a Gardner color number of 5, and was free from turbidity, thus exhibiting good visibility of the solution. In addition, the coatability is particularly good, and the initial curability is remarkably good, and remarkably high strength can be expected. was good.
(Example 13)
According to the composition ratio described in Table 2, the type of urethanization catalyst containing a metal component was changed from that of Example 4. Table 2 shows the results of Example 13. As compared with Example 4, the Gardner color number at 15 parts by weight of the polyalkylene oxide (B1) was slightly lowered and the visibility was improved. The composition solution containing the NCO group-terminated urethane prepolymer (D) had no gels or precipitates and was slightly turbid (especially at low temperatures), but was highly transparent and had a moderate coloration. showed visibility. In addition, the initial curability is remarkably good, and remarkably high strength can be expected. It had a moderate coloration and good visibility.
(Examples 14-17)
According to the composition ratios described in the examples in Table 2, the polyisocyanate (C2) was used, the polyol (A), the polyalkylene oxide (B), the type of the urethanization catalyst containing the metal component, and the ratio of the amounts charged were changed. It is manufactured by Table 2 shows the results of Examples 14-17. The composition solution containing the NCO group-terminated urethane prepolymer (D) was remarkably highly transparent without gels or precipitates, had moderate coloring, and exhibited good visibility of the solution. In Example 15, in which the amount of the urethanization catalyst containing the metal component was small, and in Example 16, in which the amount of the high-boiling glycol ether solvent was large, the initial curability was slightly lowered and the coating film became slightly cloudy, but it can be used. All of them exhibit good curability and transparency in the range of 0.5%, and both of them have good initial curability and can be expected to have significantly higher strength. and visibility was good.

All of the urethane prepolymer composition solutions 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. The viscosity at 70° C., which is the reaction temperature, was in the range of 0.3 to 20 Pa·s, indicating good handleability and good fluidity. 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.

From the above, in addition to the NCO group-terminated urethane prepolymer (D), a urethanization catalyst containing a metal component and a glycol ether solvent with an sp value of 8.0 or more are included to obtain a specific Gardner color number. It is a highly transparent urethane prepolymer composition solution with good properties, and it has good curability and can be expected to have significantly higher strength. It was shown that the visibility becomes good as a result.

<Comparative example>
(Comparative example 1)
According to the production example of the urethane prepolymer composition solution and the composition ratio described in Comparative Example 1 in Table 3, a urethanization catalyst containing a metal component with a composition that does not give a specific Gardner color number, an sp value of 8.0 or more It is a urethane prepolymer composition solution containing a glycol ether solvent and an NCO group-terminated urethane prepolymer (DC). Table 3 shows the results of Comparative Example 1. The composition solution containing NCO group-terminated urethane prepolymer (DC) was highly transparent with no gels or precipitates. was inferior and difficult to use. In addition, the initial curability is remarkably good and remarkably high strength can be expected, but the cured urethane coating film does not have appropriate coloration and has poor visibility, making it difficult to use. Met.
(Comparative example 2)
Compared to Comparative Example 1, a colored polyalkylene oxide (B1) was added to give a specific Gardner color number. Table 3 shows the results of Comparative Example 2. Although the composition has a specific Gardner color number, the urethane prepolymer composition solution is cloudy and precipitates, so the composition solution is poor in transparency and difficult to use. However, it was cloudy and had a poor appearance, making it difficult to use.
(Comparative Example 3)
In comparison with Comparative Example 2, the active hydrogen group-terminated urethane prepolymer (DC2) was changed to an NCO group-terminated urethane prepolymer (DC3) with a similar composition, and did not contain a glycol ether solvent with an sp value of 8.0 or more. A urethane prepolymer composition. Table 3 shows the results of Comparative Example 2. Although the composition contains an NCO group-terminated urethane prepolymer and has a specific Gardner color number, it does not contain a glycol ether solvent with an sp value of 8.0 or more, so the compatibility is poor and the composition has poor transparency. The wrinkles of the resulting urethane cured product could not be suppressed, and the appearance was poor, making it difficult to use.
(Comparative Example 4)
A urethane prepolymer composition solution containing a urethanization catalyst containing a metal component, a glycol ether solvent having an sp value of 8.0 or more, and an NCO group-terminated urethane prepolymer, but having a composition exceeding a specific Gardner color number. . Table 3 shows the results of Comparative Example 4. Since the specific Gardner color number was exceeded, the coloring of the solution was too strong, the visibility inside the solution was poor, and the visibility of insolubles and residues was insufficient, making it difficult to use the urethane prepolymer composition solution.
(Comparative Example 5)
Compared to Comparative Example 3, the amount of polyalkylene oxide (B1) having a rigid aromatic amine residue was reduced in order to improve compatibility while maintaining a specific Gardner color number range, but sp value is 8.0 or more and does not contain a glycol ether solvent. Table 3 shows the results of Comparative Example 4. Since the amount of polyalkylene oxide (B1) used is not too large at a specific Gardner color number, the solution has good transparency, moderate coloring, and good visibility, but the sp value is 8.0 or more. Since it does not contain a glycol ether solvent, the wrinkles of the resulting urethane cured product cannot be suppressed, resulting in inferior appearance and difficulty in use.
(Comparative Example 6, Comparative Example 7)
According to the composition ratio described in Comparative Examples in Table 3, a urethanization catalyst containing a metal component with a composition that does not give a specific Gardner color number, a glycol ether solvent with an sp value of 8.0 or more, an NCO group-terminated urethane prepolymer (DC ) containing polyol (A) and polyalkylene oxide (B) obtained by changing the type of urethane prepolymer composition solution. Table 3 shows the results of Comparative Examples 6 and 7. Since the composition solution containing the NCO group-terminated urethane prepolymer (DC) is below the specific Gardner color number, it does not have appropriate coloration and the visibility of the solution is poor, making it difficult to use. In addition, the coating film of the cured urethane obtained was not appropriately colored and had poor visibility, making it difficult to use.
(Comparative Example 8)
In contrast to Comparative Example 4, a urethanization catalyst containing a colored metal component was not used, and instead a poly having a rigid aromatic amine residue that was colored within the range of a specific Gardner color number and had catalytic activity was used. This is a urethane prepolymer composition solution obtained by increasing the amount of alkylene oxide (B1) and increasing the amount of solvent. Table 3 shows the results of Comparative Example 8. A urethane prepolymer composition solution that is strongly colored but exhibits good visibility within the usable range, but has insufficient curability and is difficult to use because it does not contain a urethanization catalyst containing a metal component. there were.
(Comparative Example 9)
This is a urethane prepolymer composition solution obtained by adding a urethanization catalyst containing a metal component in order to improve curability as compared with Comparative Example 8, and exceeds a specific Gardner color number. Table 3 shows the results of Comparative Example 9. The curability was improved compared to Comparative Example 8, but since the specific Gardner color number was exceeded, the visibility of the solution was insufficient and it was difficult to use. It was a urethane prepolymer composition solution that was difficult to use due to its poor appearance.
(Comparative Examples 10-12)
It is a urethane prepolymer composition solution obtained by changing the ratio of polyisocyanate (C), the use or non-use of a glycol ether solvent, and the use or non-use of polyalkylene oxide (B1) or monool (AC1) with respect to Comparative Example 1. , are all below a certain Gardner color number. Table 3 shows the results of Comparative Examples 10-12. The composition solution containing the NCO group-terminated urethane prepolymer (DC) was highly transparent with no gels or precipitates. Regardless of whether or not B1) or monool (AC1) was used, the color was less than the specific Gardner color number, and thus the solution did not have appropriate coloration and the visibility of the solution was poor, making it difficult to use. In addition, both of them had remarkably good initial curability and could be expected to have remarkably high strength, but the cured urethane coating film did not have appropriate coloring and had poor visibility, making it difficult to use. It was something.
(Comparative Example 13)
In contrast to Comparative Example 10, a urethanization catalyst containing a metal component was added instead of containing a polyalkylene oxide (B2) having a sucrose residue having a colored and rigid structure in order to obtain a specific Gardner color number. It is a urethane prepolymer composition solution that does not contain Table 3 shows the results of Comparative Example 13. It was a urethane prepolymer composition solution that had moderate coloring and good visibility, but had insufficient curability and was difficult to use because it did not contain a urethanization catalyst containing a metal component.
(Comparative Example 14)
A polyisocyanate (C2) is used as the polyisocyanate (C), and a urethanization catalyst containing a metal component and a urethane prepolymer having an NCO group end are included in a composition ratio that provides a specific Gardner color number, but the sp value is 8.0 or more. is a urethane prepolymer composition solution using methyl ethyl ketone with an sp value of 9.0 and containing no glycol ether structure instead of containing no glycol ether solvent. Table 3 shows the results of Comparative Example 14. Since it does not contain a glycol ether solvent having an sp value of 8.0 or more, wrinkles in the resulting urethane cured product cannot be suppressed, resulting in inferior appearance and difficulty in use.
(Comparative Example 15)
A urethanization catalyst containing a metal component in a composition ratio that provides a specific Gardner color number, a glycol ether solvent with an sp value of 8.0 or more, and a glycol with an sp value of 8.0 or more, including an NCO group-terminated urethane prepolymer. A urethane prepolymer composition solution containing more than 20% by weight of an ether solvent. Table 3 shows the results of Comparative Example 15. Since it contains a large amount of glycol ether solvent with good compatibility and a high boiling point sp value of 8.0 or more, there is a decrease in curability and an odor, which is thought to be due to insufficient drying and curing, and remarkably high strength can be expected. Therefore, it was a urethane prepolymer composition solution that was difficult to use.
(Comparative Example 16)
In contrast to Comparative Example 5, polyisocyanate (C2) was used as polyisocyanate (C), and a urethanization catalyst containing a metal component in a composition ratio that gave a specific Gardner color number, and an NCO group-terminated urethane prepolymer. but does not contain a glycol ether solvent with an sp value of 8.0 or more. Table 3 shows the results of Comparative Example 16. Although the transparency of the solution is good, the coloration is appropriate, and the visibility is good, since it does not contain a glycol ether solvent with an sp value of 8.0 or more, wrinkles in the resulting urethane cured product cannot be suppressed, resulting in poor appearance. It was inferior and difficult to use.
(Comparative Example 17)
A urethane prepolymer composition that uses dipropylene glycol dimethyl ether, which is a glycol ether solvent with an sp value of less than 8.0, and does not contain a glycol ether solvent with an sp value of 8.0 or more, as compared with Comparative Example 3. solution. Table 3 shows the results of Comparative Example 17. Although the composition contains an NCO group-terminated urethane prepolymer and has a specific Gardner color number, it does not contain a glycol ether solvent with an sp value of 8.0 or more, so the compatibility is poor and the composition has poor transparency. The wrinkles of the resulting urethane cured product could not be suppressed, and the appearance was poor, making it difficult to use.

As described above, as shown in the comparative examples, urethanization catalysts containing metal components, glycol ether solvents having an sp value of 8.0 or more, those not containing NCO group-terminated urethane prepolymers (D), and specific Gardner colors Those with an innumerable composition, those with a specific composition and solid content ratio that do not contain a glycol ether solvent, are expected to have transparency and high visibility of the solution, and high strength of the resulting urethane cured product. It was difficult to satisfy all visibility requirements.

<Production example 1 of cured urethane>
For 100 parts by weight of the solid content of the urethane prepolymer composition solutions of Examples 3 and 6, 5 parts by weight of acetylacetone as a reaction retarder and 600 ppm of acidic phosphate ester (JP508 manufactured by Johoku Kagaku Kogyo Co., Ltd.), and tinuvin as a triazole stabilizer. 0.8 parts by weight of 99-2, 10 parts by weight of hexadecyl 2-ethylhexanoate as a plasticizer, 1.5 parts by weight of 1-ethyl-3-methylimidazolium bis(fluoromethanesulfonyl)imide as an antistatic agent, leveling 0.05 parts by weight of DIC F-571 is mixed and dispersed as an agent, coated on a PET substrate at a thickness of 80 μm or less, dried at 130° C. for 5 minutes, and aged at room temperature for 1 week. A coating film was prepared. The viscosity of the composition solution containing the urethane prepolymer (D) of any of the examples was in the range of 1 to 100 Pa·s, and the residual liquid of the composition after sheet formation exhibited good fluidity even after 24 hours. rice field. 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.

<Production example 2 of cured urethane>
The polyalkylene oxide (B1) was added at a ratio of 30 parts by weight to 100 parts by weight of the solid content of the urethane prepolymer composition solutions of Examples 1 and 12, and reacted to form an active hydrogen group terminal with high storage stability. Forms urethane prepolymer.

5 parts by weight of acetylacetone as a reaction retarder and 600 ppm of acidic phosphoric ester (JP508 manufactured by Johoku Kagaku Kogyo Co., Ltd.) and 0.8 parts by weight of triazole stabilizer Tinuvin 99-2 with respect to 100 parts by weight of the urethane prepolymer terminated with an active hydrogen group. , 0.2 parts by weight of diethylene glycol, 10 parts by weight of hexadecyl 2-ethylhexanoate as a plasticizer, 1.5 parts by weight of 1-ethyl-3-methylimidazolium bis(fluoromethanesulfonyl)imide as an antistatic agent, and as a leveling agent 0.05 parts by weight of F-571 manufactured by DIC was mixed and dispersed, and 1.1 equivalent of coronate HXLV, which is an isocyanate compound (F1) as a cross-linking agent, was mixed with respect to hydroxyl groups, and the mixture was coated on a PET substrate at a thickness of 80 μm or less. and dried at 130° C. for 5 minutes to prepare a urethane coating film. The viscosity of the urethane prepolymer composition solution of each 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 (D) in the present invention has no gel-like substance or precipitate, is highly transparent and has good visibility, has good curability and high strength. It is a urethane prepolymer composition solution that contributes to the formation of a cured product, and by using the urethane prepolymer (D), a highly transparent and highly visible urethane coating film can be stably formed.

It was shown that the polyurethane obtained using the urethane prepolymer (D) can be suitably used for sealants, paints, pressure-sensitive adhesives, adhesives and the like by making use of its characteristics.

Claims (6)

A urethane prepolymer composition solution containing an NCO group-terminated urethane prepolymer (D), a urethanization catalyst containing a metal component, and a glycol ether solvent having an sp value of 8.0 or more,
The urethane prepolymer (D) is a reaction product of polyol (A) and polyisocyanate (C),
The content of the glycol ether solvent having an sp value of 8.0 or more is in the range of 0.1 to 20% by weight,
The concentration of the urethane prepolymer (D) is 75% by weight or more and 99.9% by weight or less,
Gardner color number is in the range of 2 or more and 13 or less,
Urethane prepolymer composition solution. The molar ratio (NCO/OH ratio) of the sum of the hydroxyl groups of the polyol (A) forming the urethane prepolymer (D) and the sum of the NCO groups of the polyisocyanate is in the range of 1.30 to 5.00. The urethane prepolymer composition solution according to claim 1. 3. The urethane prepolymer composition solution according to claim 1, wherein the viscosity at 70° C. is in the range of 0.1 to 30 Pa·s. The urethane according to any one of claims 1 to 3, wherein the content of the urethanization catalyst containing a metal component is in the range of 0.001 to 0.05 parts by weight with respect to 100 parts by weight of the urethane prepolymer (D). Prepolymer composition solution. A cured polyurethane product obtained by using the urethane prepolymer composition solution according to any one of claims 1 to 4. A polyurethane sheet comprising the cured urethane material according to claim 5 .