Polyester polyol, polyurethane resin, and method for producing polyurethane resin

Abstract

To provide polyester polyol which enables production of a reaction product having enhanced solvent resistance.SOLUTION: Polyester polyol contains a polyhydric carboxylic acid residue, and a polyhydric alcohol residue. The polyhydric carboxylic acid residue contains a 2,6-naphthalenedicarboxylic acid residue.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a polyester polyol, a polyurethane resin, and a method for producing a polyurethane resin.

Background Art

[0002] Patent Document 1 discloses a polyester polyol containing, as constituent components, 1,3-propanediol having an alicyclic skeleton in a side chain and a dibasic acid component, and having an alkali metal content of 20 mass ppm or less. It is disclosed that the above polyester polyol can suppress gelation in the case of performing a urethanization reaction and can produce a polyurethane resin with stable quality.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Reaction products such as polyurethane resins produced from polyester polyols are used, for example, to produce a coating film covering the outermost surface of a molded article or a material. Depending on the use environment, the molded article or the coating film may come into contact with a material containing a solvent. Therefore, it is desirable that the reaction product has high solvent resistance.

[0005] An object of the present disclosure is to provide a polyester polyol, a polyurethane resin, and a method for producing a polyurethane resin that can produce a reaction product with enhanced solvent resistance.

Means for Solving the Problems

[0006] A polyester polyol according to one aspect of the present disclosure contains a polyvalent carboxylic acid residue and a polyvalent alcohol residue. The polyvalent carboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue.

[0007] A polyurethane resin according to one aspect of the present disclosure includes a reaction product of the polyester polyol and an isocyanate compound.

[0008] A method for producing a polyurethane resin according to one aspect of the present disclosure includes reacting a hydroxyl group of the polyester polyol with an isocyanate group of the isocyanate compound. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a polyester polyol, a polyurethane resin, and a method for producing a polyurethane resin that can produce a reaction product with enhanced solvent resistance. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will now be described. Note that the embodiments described below are only a selection of the various embodiments of this disclosure. Furthermore, the embodiments described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. While the mechanisms of operation in the embodiments may be described below, these descriptions include speculative explanations, and this disclosure is not bound by these descriptions of mechanisms of operation.

[0011] 1. Overview The polyester polyol according to the embodiment (hereinafter also referred to as polyester polyol (A)) contains a polyvalent carboxylic acid residue and a polyvalent alcohol residue. The polyvalent carboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue. With this configuration, polyester polyol (A) according to the embodiment can produce reaction products with enhanced solvent resistance.

[0012] In the present disclosure, the polyvalent carboxylic acid residue refers to the portion obtained by removing OH from the carboxy group of the polyvalent carboxylic acid represented by formula (1). In formula (1), R , , , , , ,

[0019] , ,

[0018] is a substituted or unsubstituted hydrocarbon group having 1 to 50 carbon atoms.

[0013] [Chemical formula]

[0014] The polyhydric alcohol residue refers to the portion obtained by removing a hydrogen atom from the hydroxyl group of the polyhydric alcohol represented by formula (2). In formula (2), R 2 is a substituted or unsubstituted hydrocarbon group having 1 to 50 carbon atoms.

[0015] [Chemical formula]

[0016] In addition, in formulas (1) and (2), * indicates the site where it binds to the group adjacent to the residue represented by formula (1) or (2) or the adjacent residue.

[0017] The polyester polyol (A) is particularly preferably used for producing a polyurethane resin. Therefore, the reaction product according to the embodiment is a polyurethane resin (hereinafter also referred to as polyurethane resin (B)).

[0018] 2. Polyester polyol The polyester polyol according to the embodiment will be described in detail.

[0019] 2.1 Characteristics [[ID=W44]](Solubility) The polyester polyol (A) has enhanced solubility in general-purpose organic solvents. In particular, the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents is likely to be enhanced. In this case, using non-halogenated solvents and non-pyrrolidone solvents, the polyester polyol (A) can be efficiently reacted with a compound capable of reacting with the hydroxyl groups of the polyester polyol (A). That is, by using the polyester polyol (A) according to the embodiment, there is an advantage that various reaction products can be produced from the polyester polyol (A) without using solvents with a large environmental load such as halogenated solvents and pyrrolidone solvents.

[0020] Note that the above characteristics of the polyester polyol (A) can be realized by appropriately adjusting the polyvalent carboxylic acid residues and polyhydric alcohol residues contained in the polyester polyol (A) within the range described below.

[0021] 2.2 Composition (Polyvalent carboxylic acid residue) As described above, the polyester polyol (A) contains polyvalent carboxylic acid residues. And the polyvalent carboxylic acid residues include 2,6-naphthalenedicarboxylic acid residues. The ratio of the 2,6-naphthalenedicarboxylic acid residues to the total polyvalent carboxylic acid residues contained in the polyester polyol (A) is preferably 30 mol% or more and 80 mol% or less. If this ratio is 30 mol% or more, the solvent resistance of the reaction product produced from the polyester polyol (A) can be further enhanced. If this ratio is 80 mol% or less, the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents can be easily enhanced. This ratio is preferably 35 mol% or more, and more preferably 45 mol% or more. This ratio is more preferably 75 mol% or less, and even more preferably 70 mol% or less.

[0022] Furthermore, the polyvalent carboxylic acid residue includes, for example, a 2,6-naphthalenedicarboxylic acid residue, as well as at least one selected from the group consisting of aromatic dicarboxylic acid residues other than 2,6-naphthalenedicarboxylic acid residues and aliphatic dicarboxylic acid residues. The aromatic dicarboxylic acid residues other than 2,6-naphthalenedicarboxylic acid include, for example, at least one selected from the group consisting of terephthalic acid residues, isophthalic acid residues, orthophthalic acid residues, diphenic acid residues, naphthalic acid residues, 1,2-naphthalenedicarboxylic acid residues, 1,4-naphthalenedicarboxylic acid residues, 1,5-naphthalenedicarboxylic acid residues, and 2,7-naphthalenedicarboxylic acid residues.

[0023] Furthermore, the polycarboxylic acid residue preferably further includes at least one selected from the group consisting of isophthalic acid residues and terephthalic acid residues. In this case, the solvent resistance of the reaction product produced from polyester polyol (A) can be further enhanced. Preferably, the total ratio of terephthalic acid residues and isophthalic acid residues to the total polycarboxylic acid residues contained in polyester polyol (A) is 20 mol% or more and 70 mol% or less. If this ratio is 20 mol% or more, the solvent resistance of the reaction product produced from polyester polyol (A) can be further enhanced. If this ratio is 70 mol% or less, the solubility of polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents can be further enhanced. This ratio is more preferably 25 mol% or more, and even more preferably 35 mol% or more. This ratio is more preferably 65 mol% or less, and even more preferably 55 mol% or less.

[0024] Furthermore, it is preferable that the total proportion of 2,6-naphthalenedicarboxylic acid residues, terephthalic acid residues, and isophthalic acid residues relative to the total polycarboxylic acid residues contained in polyester polyol (A) is 50 mol% or more and 100 mol% or less. If this proportion is 50 mol% or more, the solvent resistance of the reaction product produced from polyester polyol (A) can be further improved. This proportion is more preferably 60 mol% or more, and even more preferably 70 mol% or more. It should be noted that these polycarboxylic acid residues do not contain orthophthalic acid residues, as orthophthalic acid esters, which are of concern due to their harmfulness, may be produced as by-products.

[0025] The aliphatic dicarboxylic acid residues include, for example, at least one selected from the group consisting of oxalic acid residues, malonic acid residues, succinic acid residues, maleic acid residues, fumaric acid residues, itaconic acid residues, glutaric acid residues, adipic acid residues, pimelic acid residues, 2,2-dimethylglutaric acid residues, suberic acid residues, azelaic acid residues, sebaciic acid residues, dodecanediic acid residues, 1,3-cyclopentanedicarboxylic acid residues, 1,4-cyclohexanedicarboxylic acid residues, diglycolic acid residues, and thiodipropionic acid residues. Preferably, the proportion of aliphatic dicarboxylic acid residues to the total polycarboxylic acid residues contained in polyester polyol (A) is 50 mol% or less. In this case, the solvent resistance of the reaction product produced from polyester polyol (A) can be easily improved.

[0026] Furthermore, the aliphatic dicarboxylic acid residue may include a linear or branched polycarboxylic acid residue having 2 to 10 carbon atoms excluding the carboxyl group carbon atoms, from the viewpoint of adjusting the glass transition temperature (Tg). Since the carbon number is 2 or more, it is possible to easily lower the glass transition temperature (Tg) of the polyester polyol (A). It is also possible to easily improve solubility in non-halogenated solvents and non-pyrrolidone solvents. Since the carbon number is 10 or less, it is possible to easily improve the solvent resistance of the reaction product produced from the polyester polyol (A). It is preferable that the carbon number is 8 or less. Specifically, the linear polycarboxylic acid residue includes at least one selected from the group consisting of succinic acid residues, adipic acid residues, azelaic acid residues, sebaciic acid residues, and dodecanediic acid residues. Furthermore, it is preferable that the ratio of linear polycarboxylic acid residues to the total polycarboxylic acid residues contained in the polyester polyol (A) is 0 mol% to 50 mol%. If this ratio is 50 mol% or less, the solvent resistance of the reaction product produced from polyester polyol (A) can be easily improved. This ratio is more preferably 40 mol% or less, and even more preferably 30 mol% or less.

[0027] Furthermore, it is preferable that the polycarboxylic acid residues do not include polycarboxylic acid residues with a valency of 3 or higher. In this case, the branched structure of polyester polyol (A) can be reduced. Therefore, the solubility of polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents can be particularly easily improved. The polycarboxylic acid residues with a valency of 3 or higher include, for example, at least one selected from the group consisting of hemimellitic acid residues, trimellitic acid residues, trimesic acid residues, pyromellitic acid residues, benzenepentacarboxylic acid residues, melliotic acid residues, cyclopropane-1,2,3-tricarboxylic acid residues, cyclopentane-1,2,3,4-tetracarboxylic acid residues, and ethanetetracarboxylic acid residues. When polycarboxylic acid residues with a valency of 3 or higher are included, it is preferable that the proportion of polycarboxylic acid residues with a valency of 3 or higher to the total polycarboxylic acid residues contained in polyester polyol (A) is 10 mol% or less, and more preferably 5 mol% or less.

[0028] (Polyhydric alcohol residue) As described above, polyester polyol (A) contains polyhydric alcohol residues. The polyhydric alcohol residues include, for example, at least one selected from the group consisting of ethylene glycol residues, polyethylene glycol residues, 1,2-propanediol residues, 1,3-propanediol residues, polypropylene glycol residues, 1,3-butanediol residues, 1,4-butanediol residues, 1,5-pentanediol residues, 1,6-hexanediol residues, neopentyl glycol residues, 2-ethyl-2-butyl-1,3-propanediol residues, 2-ethyl-2-isobutyl-1,3-propanediol residues, 2,2,4-trimethyl-1,6-hexanediol residues, 1,2-cyclohexanedimethanol residues, 1,3-cyclohexanedimethanol residues, 1,4-cyclohexanedimethanol residues, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues. It is preferable that these polyhydric alcohol residues do not contain bisphenol residues, which are of concern due to their harmful effects.

[0029] Furthermore, from the viewpoint of adjusting the glass transition temperature (Tg), the polyhydric alcohol residue preferably includes a linear or branched polyhydric alcohol residue having 3 to 6 carbon atoms. Having 3 or more carbon atoms makes it easier to improve the solubility of the polyester polyol (A) in non-halogenated and non-pyrrolidone solvents. Having 6 or fewer carbon atoms makes it easier to improve the solvent resistance of the reaction product produced from the polyester polyol (A). Specifically, the linear polyhydric alcohol residue includes at least one selected from the group consisting of 1,2-propanediol residues, 1,3-propanediol residues, 1,3-butanediol residues, 1,4-butanediol residues, 1,6-hexanediol residues, and neopentyl glycol residues.

[0030] Furthermore, it is preferable that the proportion of chain-like polyhydric alcohol residues to the total polyhydric alcohol residues contained in polyester polyol (A) is 20 mol% or more and 70 mol% or less. If this proportion is 20 mol% or more, the solubility of polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents can be easily increased. If this proportion is 70 mol% or less, the solvent resistance of the reaction product produced from polyester polyol (A) can be increased. This proportion is more preferably 30 mol% or more, and even more preferably 40 mol% or more. This proportion is more preferably 60 mol% or less, and even more preferably 55 mol% or less.

[0031] Furthermore, it is preferable that the polyhydric alcohol residues do not contain polyhydric alcohol acid residues with a valency of 3 or higher. In this case, the branched structure of polyester polyol (A) can be reduced. Therefore, the solubility of polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents can be easily improved. The polyhydric alcohol residues with a valency of 3 or higher include, for example, at least one selected from the group consisting of aliphatic triol residues such as glycerol residues, trimethylolpropane residues, and pentaerythritol residues; alicyclic triol residues such as 1,2,4-cyclohexanetrimethanol residues; and aromatic triol residues such as benzenetrimethanol residues. When the polyhydric alcohol residues include polyhydric alcohol residues with a valency of 3 or higher, it is preferable that the proportion of polyhydric alcohol residues with a valency of 3 or higher to the total polyhydric alcohol residues contained in polyester polyol (A) is 10 mol% or less, and more preferably 5 mol% or less.

[0032] With respect to the polyester polyol (A) according to the embodiment, it is particularly preferable that the polycarboxylic acid residues do not contain polycarboxylic acid residues of trivalent or higher, and that the polyhydric alcohol residues do not contain polyhydric alcohol acid residues of trivalent or higher. In this case, the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents can be particularly easily improved.

[0033] 2.3 Physical Properties The physical properties of polyester polyol (A) are preferably adjusted to a specific range. The following physical properties can be achieved by appropriately adjusting the polycarboxylic acid residues and polyalcohol residues contained in polyester polyol (A) within the range described above.

[0034] (Acid value) The acid value of the polyester polyol (A) according to the embodiment is preferably 5 mg KOH / g or less. In this case, the polyester polyol (A) can react efficiently with the isocyanate compound. The acid value is more preferably 4 mg KOH / g or less, and even more preferably 3 mg KOH / g or less. The lower the acid value of the polyester polyol (A), the better, and it may even be 0 mg KOH / g. In this disclosure, the acid value refers to the number of mg of potassium hydroxide required to neutralize 1 g of a sample such as polyester polyol (A).

[0035] (Hydroxyl value) The hydroxyl value of the polyester polyol (A) according to the embodiment is preferably 18 mg KOH / g or more and 225 mg KOH / g or less. If the hydroxyl value is 18 mg KOH / g or more, the polyester polyol (A) can react more efficiently with the isocyanate compound. If the hydroxyl value is 225 mg KOH / g or less, the proportion of the polyester polyol (A) skeleton contained in the polyurethane resin (B) can be increased. This makes it possible to further improve the solvent resistance of the polyurethane resin (B) produced from the polyester polyol (A). The hydroxyl value is more preferably 25 mg KOH / g or more, and even more preferably 35 mg KOH / g or more. The hydroxyl value is more preferably 170 mg KOH / g or less, and even more preferably 130 mg KOH / g or less. In this disclosure, the hydroxyl value refers to the number of mg of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl group when 1 g of a sample such as polyester polyol (A) is acetylated.

[0036] (number average molecular weight) The number-average molecular weight of the polyester polyol (A) according to the embodiment is, for example, 500 to 6200. If the number-average molecular weight is within the above range, the polyester polyol (A) can react more efficiently with the isocyanate, and the solvent resistance of the polyurethane resin (B) produced from the polyester polyol (A) can be further improved. The number-average molecular weight is preferably 650 or more, and more preferably 850 or more. The number-average molecular weight is more preferably 4500 or less, and even more preferably 3200 or less. In this disclosure, the number-average molecular weight of the polyester polyol (A) is a calculated value obtained from the hydroxyl value of the polyester polyol (A).

[0037] (Glass transition temperature) The glass transition temperature (Tg) of the polyester polyol (A) according to the embodiment is preferably 10°C or higher and 100°C or lower. If the Tg of polyester polyol (A) is 10°C or higher, the reaction product produced from polyester polyol (A) is less likely to become excessively sticky, resulting in better handling and, in addition, better suppression of tack formation. If the Tg of polyester polyol (A) is 100°C or lower, the reaction product produced from polyester polyol (A) has better film-forming properties, resulting in improved adhesion to the substrate and improved priming properties. The Tg of polyester polyol (A) is more preferably 20°C or higher, and even more preferably 30°C or higher. The Tg of polyester polyol (A) is more preferably 80°C or lower, and even more preferably 70°C or lower.

[0038] 2.4 Manufacturing method A method for producing polyester polyol (A) according to the embodiment will now be described. Polyester polyol (A) can be produced by polycondensation of monomer components containing a polycarboxylic acid component and a polyhydric alcohol component. For example, if the polycarboxylic acid component is a polycarboxylic acid and the polyhydric alcohol component is a polyhydric alcohol, a direct esterification reaction can be used to react the polycarboxylic acid and the polyhydric alcohol in a single step. Alternatively, if the polycarboxylic acid component is an esterifying derivative of a polycarboxylic acid such as terephthalic acid ester and the polyhydric alcohol component is a polyhydric alcohol, polyester polyol (A) can be produced by a first-stage reaction which is a transesterification reaction between the esterifying derivative of the polycarboxylic acid and the polyhydric alcohol, and a second-stage reaction in which the reaction product from the first-stage reaction undergoes polycondensation. The raw materials used to produce polyester polyol (A) in the reaction system may be added in stages, or all raw materials may be included from the beginning.

[0039] A method for producing polyester polyol (A) through a first-stage reaction and a second-stage reaction will be described in detail.

[0040] First, the transesterification reaction, which is the first stage of the reaction, is carried out by gradually raising the temperature to 150-260°C under atmospheric pressure and in an inert gas atmosphere such as nitrogen gas, while the ester-forming derivative of the polycarboxylic acid and the polyhydric alcohol are held in a reaction vessel.

[0041] Next, the second reaction, polycondensation, is carried out. The reaction conditions at this stage are, for example, a reduced pressure of 6.7 hPa (5 mmHg) or less, and a temperature within the range of 150 to 260°C.

[0042] Furthermore, catalysts may be used in the first and second reactions. The catalyst includes at least one selected from the group consisting of, for example, titanium, antimony, lead, zinc, magnesium, calcium, manganese, and alkali metal compounds.

[0043] By the method described above, the polyester polyol (A) according to the embodiment can be produced. However, the method described above is merely an example, and the manufacturing method is not particularly limited as long as it can produce the polyester polyol (A) according to the embodiment.

[0044] 3. Application Examples An example of the application of the polyester polyol (A) according to the embodiment will be described.

[0045] Polyester polyol (A) can be used as a reactant to produce various reaction products. In this case, reaction products with enhanced solvent resistance can be produced from polyester polyol (A).

[0046] For example, the reaction product can be obtained by reacting a polyester polyol (A) with a compound that can react with the hydroxyl groups of the polyester polyol (A). The compound that can react with the hydroxyl groups of the polyester polyol (A) is not particularly limited, but isocyanate compounds are preferably used. In other words, the polyester polyol (A) according to the embodiment is preferably used to synthesize a polyurethane resin (B), and in the embodiment, the polyurethane resin (B) obtained by reacting the polyester polyol (A) with an isocyanate compound will be described.

[0047] 3.1 Polyurethane resin The properties of the polyurethane resin (B) according to the embodiment will be described.

[0048] As described above, the polyurethane resin (B) according to the embodiment uses polyester polyol (A), and therefore the solvent resistance of the polyurethane resin (B) is enhanced.

[0049] Furthermore, the polyurethane resin (B) according to the embodiment is manufactured from a polyester polyol (A) having the composition and physical properties described above, thereby improving the adhesion of the polyurethane resin (B) to the PET substrate.

[0050] Furthermore, the tensile strength of polyurethane resin (B) has been increased. Although the exact reason for this property has not been clarified, it is presumed that it is possible to incorporate a structure derived from 2,6-naphthalenedicarboxylic acid into polyurethane resin (B).

[0051] Thus, the polyurethane resin (B) according to the embodiment can simultaneously achieve improved solvent resistance, adhesion to PET substrates, and tensile strength.

[0052] The composition of the polyurethane resin (B) according to the embodiment will be described.

[0053] As described above, the polyurethane resin (B) according to the embodiment is obtained by the reaction of a polyester polyol (A) and an isocyanate compound. In other words, the polyurethane resin (B) may contain the reaction product of the polyester polyol (A) and the isocyanate compound.

[0054] The isocyanate compound includes, for example, at least one selected from the group consisting of aliphatic isocyanate compounds, alicyclic isocyanate compounds, aromatic isocyanate compounds, and aromatic aliphatic isocyanate compounds. The aliphatic isocyanate compound includes, for example, at least one selected from the group consisting of tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,4-butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, and 3-methylpentane-1,5-diisocyanate. Alicyclic isocyanate compounds include, for example, at least one selected from the group consisting of isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-cyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, and 1,3-bis(isocyanatemethyl)cyclohexane. Aromatic isocyanate compounds include, for example, at least one selected from the group consisting of tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyle diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, and 1,4-phenylene diisocyanate. The aromatic aliphatic isocyanate compound includes, for example, at least one selected from the group consisting of alkyldiphenylmethane diisocyanate and tetraalkyldiphenylmethane diisocyanate.

[0055] Thus, the polyurethane resin (B) according to this embodiment is obtained by the reaction of a polyester polyol (A) and an isocyanate compound, and may contain the reaction product of the polyester polyol (A) and the isocyanate compound.

[0056] The specific procedure for manufacturing polyurethane resin (B) is as follows:

[0057] First, a mixture containing polyester polyol (A) and a solvent is held in a reaction vessel. Then, under atmospheric pressure and an inert gas atmosphere such as nitrogen gas, the mixture is gradually heated while being stirred to dissolve the polyester polyol (A) in the solvent. Subsequently, an isocyanate compound is added to the solution held in the reaction vessel, and the urethane reaction is carried out by stirring the solution within a temperature range of 60 to 90°C.

[0058] In this way, polyurethane resin (B) can be manufactured. The manufacturing method described above is merely one example, and the manufacturing method is not particularly limited as long as it can produce polyurethane resin (B).

[0059] The solvent used in the production of the polyurethane resin (B) is not particularly limited, but it is preferable that it is a solvent that does not react with the isocyanate compound. Furthermore, the polyester polyol (A) according to the embodiment has enhanced solubility in non-halogenated solvents and non-pyrrolidone solvents. Therefore, non-halogenated solvents and non-pyrrolidone solvents can be used as solvents. Accordingly, when producing the polyurethane resin (B) according to the embodiment, at least one selected from the group consisting of ester solvents such as ethyl acetate, butyl acetate, and ethyl cellosolve acetate; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ether solvents such as dioxane, tetrahydrofuran, and propylene glycol monomethyl ether; and amide solvents such as dimethylformamide can be suitably used.

[0060] Furthermore, a catalyst may be used in the production of polyurethane resin (B). The catalyst includes at least one selected from the group consisting of amine catalysts such as triethylamine, N-ethylmorpholine, and triethylenediamine; tin-based catalysts such as dibutyltin dilaurate, dioctyltin dilaurate, and tin octoate; and titanium-based catalysts such as tetrabutyl titanate.

[0061] The polyurethane resin (B) produced by the above manufacturing method is recovered dissolved in the solvent used during the reaction, but the solution in which the polyurethane resin (B) is dissolved can be used as is for various purposes. In other words, according to the above manufacturing method, a polyurethane resin composition containing polyurethane resin (B) can be obtained and used for various purposes. For example, the polyurethane resin composition can be used to produce molded products, adhesives, or coatings for plastic films. Alternatively, the polyurethane resin composition may be produced by first extracting only the polyurethane resin (B) from the solution produced when the polyurethane resin (B) was manufactured, and then adding a solvent to the polyurethane resin (B).

[0062] 3.2 Polyurethane resin aqueous dispersion The applications of the polyurethane resin (B) according to this embodiment will be further explained with specific examples.

[0063] For example, polyurethane resin (B) can be dispersed in water. That is, a polyurethane resin composition (hereinafter also referred to as a polyurethane resin aqueous dispersion) containing polyurethane resin (B) dispersed in water can be obtained. The polyurethane resin (B) contained in the polyurethane resin aqueous dispersion may include components obtained by the reaction of a polyester polyol (A) and an isocyanate compound and an additive. That is, the polyurethane resin (B) according to the embodiment may contain only the reaction product of polyester polyol (A) and an isocyanate compound, but is not limited thereto. For example, polyurethane resin (B) may contain at least one selected from the group consisting of the reaction product of polyester polyol (A) and an isocyanate compound and components obtained by further reaction of the reaction product with a compound different from polyester polyol (A) and the isocyanate compound.

[0064] For example, the additive includes at least one selected from the group consisting of neutralizing agents and chain extenders.

[0065] The neutralizing agent can neutralize the reaction product formed by the reaction of polyester polyol (A) and isocyanate compound. This makes it easier to disperse the polyurethane resin (B) in water. The neutralizing agent includes, for example, at least one selected from the group consisting of ammonia, N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolamine, morpholine, tripropylamine, ethanolamine, triisopropanolamine, and 2-amino-2-methyl-1-propanol.

[0066] The chain extender can react with isocyanate groups. For example, if the reaction product formed by the reaction of polyester polyol (A) and an isocyanate compound has an isocyanate group, that isocyanate group can react with the chain extender. This allows the reaction products formed by the reaction of polyester polyol (A) and the isocyanate compound to be linked together via the chain extender. As a result, the molecular weight of the polyurethane resin (B) can be increased. Examples of chain extenders include dimethylolalkanoates such as dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, and dimethylolpentanoic acid; N-alkyldialkanolamines such as N-methyldiethanolamine and N-ethyldiethanolamine; N-alkyldiaminoalkylamines such as N-methyldiaminoethylamine and N-ethyldiaminoethylamine; ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, and 1,3-butane. It comprises at least one selected from the group consisting of: diols, glycols such as 1,4-butanediol, neopentyl glycol, pentanediol, 1,6-hexanediol, and propylene glycol; aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine, and aminoethylethanolamine; alicyclic diamines such as isophoronediamine and 4,4'-dicyclohexylmethanediamine; and aromatic diamines such as xylylenediamine and tolylenediamine.

[0067] Although polyurethane resin aqueous dispersions may contain water, water can be added to the polyurethane aqueous dispersion, for example, by adding water to a solution containing the reaction product of polyester polyol (A) and an isocyanate compound during the manufacturing process of the polyurethane aqueous dispersion.

[0068] The polyurethane resin aqueous dispersion is manufactured by the following method.

[0069] First, a mixture containing polyester polyol (A) and a solvent is held in a reaction vessel. Then, under atmospheric pressure and an inert gas atmosphere such as nitrogen gas, the mixture is gradually heated while being stirred to dissolve the polyester polyol (A) in the solvent. Subsequently, an isocyanate compound is added to the solution held in the reaction vessel, and the urethane reaction is carried out by stirring the solution within a temperature range of 60 to 90°C.

[0070] Next, the aforementioned solution is cooled and neutralized by adding a neutralizing agent. Then, water is added to the neutralized solution to disperse the reaction product of polyester polyol (A) and isocyanate compound in water. Finally, the solvent used in the reaction between polyester polyol (A) and isocyanate compound is removed by distillation under reduced pressure.

[0071] A polyurethane resin aqueous dispersion can be produced using this procedure. Alternatively, the reaction can be carried out by adding a chain extender after adding the neutralizing agent and water, and then the solvent used in the reaction of polyester polyol (A), isocyanate compound, and chain extender can be removed under reduced pressure.

[0072] The polyurethane resin aqueous dispersion contains polyurethane resin (B) according to the embodiment. Therefore, a coating film formed from the polyurethane resin aqueous dispersion can simultaneously achieve improved solvent resistance, adhesion to PET substrates, and tensile strength.

[0073] 4. Appearance A polyester polyol (A) according to a first aspect of this disclosure contains a polycarboxylic acid residue and a polyalcohol residue. The polycarboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue.

[0074] According to this embodiment, a polyester polyol (A) can be provided that can produce a reaction product with enhanced solvent resistance.

[0075] In the second aspect of the present disclosure, the polyester polyol (A) is such that, in the first aspect, the proportion of 2,6-naphthalenedicarboxylic acid residues to the total polycarboxylic acid residues contained in the polyester polyol (A) is 30 mol% or more and 80 mol% or less.

[0076] A polyester polyol (A) according to a third aspect of the present disclosure further comprises, in the first or second aspect, at least one polycarboxylic acid residue selected from the group consisting of terephthalic acid residues and isophthalic acid residues.

[0077] In the fourth embodiment, the polyester polyol (A) is such that, in the third embodiment, the total proportion of terephthalic acid residues and isophthalic acid residues to the total polycarboxylic acid residues contained in the polyester polyol (A) is 20 mol% or more and 70 mol% or less.

[0078] The polyester polyol (A) according to the fifth embodiment has a hydroxyl value of 18 mg KOH / g or more and 225 mg KOH / g or less in any one of the first to fourth embodiments.

[0079] The polyester polyol (A) according to the sixth embodiment has a glass transition temperature of 10°C or more and 100°C or less in any one of the first to fifth embodiments.

[0080] The polyester polyol (A) according to the seventh embodiment is such that, in any one of the first to sixth embodiments, the polycarboxylic acid residue does not contain a polycarboxylic acid residue with three or more valent

[0081] The polyester polyol (A) according to the eighth embodiment, in any one of the first to seventh embodiments, includes a chain-like polyhydric alcohol residue having a linear or branched chain with 3 to 6 carbon atoms.

[0082] In the ninth embodiment, the polyester polyol (A) is characterized in that, in the eighth embodiment, the proportion of chain-like polyhydric alcohol residues to the total polyhydric alcohol residues contained in the polyester polyol (A) is 20 mol% or more and 70 mol% or less.

[0083] The polyester polyol (A) according to the tenth embodiment is used to synthesize a polyurethane resin (B) in any one of the first to ninth embodiments.

[0084] The polyurethane resin (B) according to the 11th embodiment includes a reaction product of a polyester polyol (A) according to the first to tenth embodiments and an isocyanate compound.

[0085] A method for producing polyurethane resin (B) according to the twelfth embodiment includes reacting a hydroxyl group of a polyester polyol (A) according to any one of the first to tenth embodiments with an isocyanate group of an isocyanate compound. [Examples]

[0086] The present disclosure will be further described below with reference to examples. However, the present disclosure is not limited to these examples.

[0087] 1. Polyester polyol 1.1 Synthesis of polyester polyols Following the description of the reaction materials shown in Table 1, a mixture was prepared by adding potassium titanium oxalate, the catalyst, and the components indicated in the "Polyhydric Carboxylic Acid Component" and "Polyhydric Alcohol Component" sections of the reaction materials column, in a 1000 ml reaction vessel equipped with a stirrer, nitrogen gas inlet, thermometer, rectification column, and condenser, such that their total mass was equal to the "Total Charge Amount / g". The molar ratio of polyhydric carboxylic acid component to polyhydric alcohol component was 1:2. This mixture was heated to 190°C under atmospheric pressure and a nitrogen atmosphere while being stirred, and then gradually heated to 240°C over 6.5 hours to allow the transesterification reaction to proceed. Next, this mixture was cooled to 170-205°C while being stirred in the reaction vessel, and at that temperature, the pressure was gradually reduced from atmospheric pressure to 0.67 hPa (0.5 mmHg), and this state was maintained for 4 hours to allow the polycondensation reaction to proceed. This yielded a polyester polyol.

[0088] 1.2 Physical Properties The hydroxyl value, number-average molecular weight, glass transition temperature, and acid value of polyester polyols were measured, and the results are shown in Table 1.

[0089] (Hydroxyl value) The hydroxyl value of polyester polyols was determined in accordance with JIS K 0070:1992 by acetylating the hydroxyl groups of the polyester polyol with an acetylating reagent, and then titrating the excess acetylating reagent with an ethanol solution of potassium hydroxide.

[0090] (number average molecular weight) The number-average molecular weight of polyester polyols was calculated from the hydroxyl value of the polyester polyols.

[0091] (Glass transition temperature) The glass transition temperature of polyester polyols was determined from the results of differential scanning calorimetry using a differential scanning calorimetry analyzer (DSCvesta, Rigaku Corporation) in accordance with JIS K 7121:2012.

[0092] (Acid value) The acid value of the polyester polyol was determined from the results of titration using a potassium hydroxide ethanol solution, in accordance with JIS K 0070:1992.

[0093] 1.3 rating We evaluated polyester polyols, and the results are shown in Table 1.

[0094] (Solubility) The obtained polyester polyols were added to glass bottles (225 mL) containing each solvent shown in Table 1 at a ratio of 50% by mass, and dissolved under stirring conditions of 60°C or 70°C for 1 hour. The appearance of the solutions containing the dissolved polyester polyols was evaluated according to the following criteria and is shown in Table 1. A: No turbidity is observed in the solution. B: The solution appears cloudy. C: Undissolved residue is visible.

[0095] [Table 1]

[0096] 2. Polyurethane resin composition 2.1 Synthesis of Polyurethane Resin Compositions According to the reaction raw materials and solvents shown in Table 2, the polyester polyol described in "1. Synthesis of Polyester Polyol" and N,N-dimethylformamide were added to a 1000 ml reaction vessel equipped with a stirrer, nitrogen gas inlet, thermometer, and cooling condenser, and the mixture was stirred at 80°C for 1 hour to homogeneously mix and dissolve. Next, an isocyanate compound was added and reacted at 80°C for 6 hours, after which ethanol was added to quench the mixture and obtain a polyurethane resin composition.

[0097] In Comparative Example 4, polytetramethylene glycol (number average molecular weight 1000) was used instead of the polyester polyol shown in "1. Synthesis of Polyester Polyol".

[0098] 2.2 Physical Properties The weight-average molecular weight, number-average molecular weight, glass transition temperature, and acid value of the polyurethane resin were measured, and the results are shown in Table 2.

[0099] (Weight average molecular weight) The weight-average molecular weight of the polyurethane resin was determined from the results of gel permeation chromatography (polystyrene equivalent). The measurement conditions are as follows. • Equipment: Shodex SYSTEM 11, manufactured by Resonaq Corporation. • Columns: Three "Shodex GPC KF-805" columns manufactured by Resonaq Corporation. • Guard column: Shodex GPC KF-G 4A, manufactured by Resonaq Corporation. • Sample concentration: Dilute with tetrahydrofuran so that the polyurethane resin concentration is 0.5% by mass. • Mobile phase solvent: tetrahydrofuran ·Flow rate: 1mL / min • Detector: Differential refractive index detector Column temperature: 40°C

[0100] (number average molecular weight) The number-average molecular weight of the polyurethane resin was determined from the results of gel permeation chromatography (polystyrene equivalent). The measurement conditions were the same as those for the weight-average molecular weight.

[0101] (Glass transition temperature) The glass transition temperature of polyurethane resin was determined from the results of differential scanning calorimetry using a differential scanning calorimetry analyzer (DSCvesta, Rigaku Corporation) in accordance with JIS K 7121:2012.

[0102] (Acid value) The acid value of the polyurethane resin was determined from the results of titration using a potassium hydroxide ethanol solution, in accordance with JIS K 0070:1992.

[0103] 2.3 rating The polyurethane resin compositions were evaluated, and the results are shown in Table 2.

[0104] (Solvent resistance) A polyurethane resin composition was applied to a PET substrate (product name "Lumirror T60#25," manufactured by Toray Industries, Inc.) to a thickness of 3 μm, and a coating film was prepared by drying at 120°C for 5 minutes. After rubbing the surface of this coating film 10 times with a cotton swab soaked in each solvent shown in Table 2, the condition of the coating film was visually observed, and the solvent resistance of the polyurethane resin was evaluated according to the following criteria. A: No changes are observed on the surface of the coating. B: Part of the coating surface turns white, or part of it dissolves. C: The majority of the coating surface turns white, or most of it dissolves.

[0105] (Adhesion) A polyurethane resin composition was applied to a PET substrate (product name "Lumirror T60#25," manufactured by Toray Industries, Inc.) to a thickness of 3 μm, and a coating film was prepared by drying at 120°C for 5 minutes. The presence or absence of peeling of the coating film was checked when Nichiban's cellophane tape (registered trademark) was applied to the coating film and then peeled off forcefully, and evaluated according to the following criteria. A: No peeling was observed in the paint film. B: Peeling was observed in part of the coating, or migration of the coating was observed in part of the cellophane tape surface. C: Peeling was observed over a large portion of the coating, or migration of the coating was observed over a large portion of the cellophane tape surface.

[0106] (Tuck-type) Similar to the above (adhesion), a coating film was prepared on a PET film. The polyurethane resin composition was applied to a PET substrate (product name "Lumirror T60#25", manufactured by Toray Industries, Inc.) to a thickness of 3 μm, and dried at 120°C for 5 minutes to prepare the coating film. An unused piece of the same PET substrate was placed on top of the coating film, and 500 g / cm² was applied from above. 2 After applying a load and holding at 20°C for 12 hours, the tackiness of the PET substrate was evaluated according to the following criteria. A: When peeling off the PET substrate, no resistance is felt. B: When peeling off the PET substrate, some resistance can be felt. C: Resistance is felt when peeling off the PET substrate.

[0107] [Table 2]

[0108] 3. Polyurethane resin aqueous dispersion 3.1 Synthesis of polyurethane resin aqueous dispersion According to the reaction raw materials and solvents shown in Table 3, the polyester polyol described in "1. Synthesis of Polyester Polyol," dimethylolpropionic acid, and methyl ethyl ketone were added to a 1000 ml reaction vessel equipped with a stirrer, nitrogen gas inlet, thermometer, and cooling condenser, and the mixture was stirred at 75°C for 1 hour to ensure uniform mixing and dissolution. Next, the isocyanate compound was added and the mixture was reacted with stirring at 75°C for 3 hours to obtain a reaction solution containing polyurethane resin. This reaction solution was then cooled to 35°C, and after neutralization with the addition of triethylamine as a neutralizing agent, the polyurethane resin was dispersed in water by gradually adding water. Subsequently, the methyl ethyl ketone was removed by distillation under reduced pressure to obtain an aqueous dispersion of polyurethane resin.

[0109] In Comparative Example 4, polypropylene glycol (number average molecular weight 1000) was used instead of the polyester polyol shown in "1. Synthesis of Polyester Polyol".

[0110] 3.2 Physical Properties The weight-average molecular weight, number-average molecular weight, glass transition temperature, and acid value of the polyester resin contained in the polyurethane resin aqueous dispersion were measured, and the results are shown in Table 3.

[0111] (Weight average molecular weight) The weight-average molecular weight of the polyurethane resin was determined from the results of gel permeation chromatography (polystyrene equivalent). The measurement conditions are as follows. • Equipment: Shodex SYSTEM 11, manufactured by Resonaq Corporation. • Columns: Three "Shodex GPC KF-805" columns manufactured by Resonaq Corporation. • Guard column: Shodex GPC KF-G 4A, manufactured by Resonaq Corporation. • Sample concentration: Dilute with tetrahydrofuran so that the polyurethane resin concentration is 0.5% by mass. • Mobile phase solvent: tetrahydrofuran ·Flow rate: 1mL / min • Detector: Differential refractive index detector Column temperature: 40°C

[0112] (number average molecular weight) The number-average molecular weight of the polyurethane resin was determined from the results of gel permeation chromatography (polystyrene equivalent). The measurement conditions were the same as those for the weight-average molecular weight.

[0113] (Glass transition temperature) The glass transition temperature of polyurethane resin was determined from the results of differential scanning calorimetry using a differential scanning calorimetry analyzer (DSCvesta, Rigaku Corporation) in accordance with JIS K 7121:2012.

[0114] (Acid value) The acid value of the polyurethane resin was determined from the results of titration using a potassium hydroxide ethanol solution, in accordance with JIS K 0070:1992.

[0115] 3.3 rating We evaluated polyurethane resin aqueous dispersions, and the results are shown in Table 3.

[0116] (Solvent resistance) A polyurethane resin aqueous dispersion was applied to a PET substrate (product name "Lumirror T60#25," manufactured by Toray Industries, Inc.) to a thickness of 3 μm, and a coating film was prepared by drying at 120°C for 10 minutes. After rubbing the surface of this coating film 10 times with a cotton swab soaked in each solvent shown in Table 2, the condition of the coating film was observed visually, and the solvent resistance of the polyurethane resin aqueous dispersion was evaluated according to the following criteria. A: No changes are observed on the surface of the coating. B: Part of the coating surface turns white, or part of it dissolves. C: The majority of the coating surface turns white, or most of it dissolves.

[0117] (Adhesion) A polyurethane resin aqueous dispersion was applied to a PET substrate (product name "Lumirror T60#25," manufactured by Toray Industries, Inc.) to a thickness of 3 μm, and a coating film was prepared by drying at 120°C for 10 minutes. The presence or absence of peeling of the coating film was checked when Nichiban's cellophane tape (registered trademark) was applied to the coating film and then peeled off forcefully, and evaluated according to the following criteria. A: No peeling was observed in the paint film. B: Peeling was observed in part of the coating, or migration of the coating was observed in part of the cellophane tape surface. C: Peeling was observed over a large portion of the coating, or migration of the coating was observed over a large portion of the cellophane tape surface.

[0118] (Tuck-type) Similar to the above (adhesion), a coating film was prepared on a PET film. The polyurethane resin composition was applied to a PET substrate (product name "Lumirror T60#25", manufactured by Toray Industries, Inc.) to a thickness of 3 μm, and dried at 120°C for 10 minutes to prepare the coating film. An unused piece of the same PET substrate was placed on top of the coating film, and 500 g / cm² was applied from above. 2 After applying a load and holding at 20°C for 12 hours, the tackiness of the PET substrate was evaluated according to the following criteria. A: When peeling off the PET substrate, no resistance is felt. B: When peeling off the PET substrate, some resistance can be felt. C: Resistance is felt when peeling off the PET substrate.

[0119] [Table 3]

Claims

1. It contains polycarboxylic acid residues and polyalcohol residues, The polyvalent carboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue. The proportion of the 2,6-naphthalenedicarboxylic acid residue to the total polycarboxylic acid residues contained in the polyester polyol is 35 mol% or more and 75 mol% or less. The polycarboxylic acid residue further comprises a terephthalic acid residue and an isophthalic acid residue, The polyhydric alcohol residue comprises an ethylene glycol residue and a linear or branched polyhydric alcohol residue having 3 to 6 carbon atoms (excluding 2-methyl-1,3-propanediol). The proportion of the chain-like polyhydric alcohol residues to the total amount of polyhydric alcohol residues contained in the polyester polyol is 20 mol% or more and 70 mol% or less. Polyester polyol.

2. The total proportion of the terephthalic acid residues and isophthalic acid residues to the total polycarboxylic acid residues contained in the polyester polyol is 20 mol% or more and 65 mol% or less. The polyester polyol according to claim 1.

3. The hydroxyl value is between 18 mg KOH / g and 225 mg KOH / g. The polyester polyol according to claim 1.

4. The glass transition temperature is between 10°C and 100°C. The polyester polyol according to claim 1.

5. The polycarboxylic acid residue does not contain a polycarboxylic acid residue with three or more valent The polyester polyol according to claim 1.

6. Used to synthesize polyurethane resin, The polyester polyol according to claim 1.

7. The reaction product comprises a polyester polyol according to any one of claims 1 to 6 and an isocyanate compound. Polyurethane resin.

8. The method involves reacting a hydroxyl group of a polyester polyol according to any one of claims 1 to 6 with an isocyanate group of an isocyanate compound. A method for manufacturing polyurethane resin.

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