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 polyester polyols, polyurethane resins, and methods for producing polyurethane resins. [Background technology]

[0002] Patent Document 1 discloses a polyester polyol containing 1,3-propanediol having an alicyclic skeleton in a side chain and a dibasic acid component as constituents, and having an alkali metal content of 20 ppm by mass or less. It is disclosed that the polyester polyol can suppress gelation during a urethanization reaction, and can produce polyurethane resins of stable quality. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 147202 Summary of the Invention [Problem to be solved by the invention]

[0004] Reaction products such as polyurethane resins produced from polyester polyols are used, for example, to produce coating films that cover the outermost surfaces of molded articles or materials. Depending on the usage environment, molded articles or coating films may come into contact with materials containing solvents. Therefore, it is desirable for the reaction products to have 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, which are capable of producing a reaction product with improved solvent resistance. [Means for solving the problem]

[0006] A polyester polyol according to one embodiment of the present disclosure contains a polycarboxylic acid residue and a polyhydric alcohol residue, wherein the polycarboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue.

[0007] A polyurethane resin according to one embodiment 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 embodiment of the present disclosure includes reacting a hydroxyl group of the polyester polyol with an isocyanate group of an isocyanate compound. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a polyester polyol, a polyurethane resin, and a method for producing a polyurethane resin, which are capable of producing a reaction product with improved solvent resistance. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present disclosure will be described. Note that the following embodiments are merely a portion of various embodiments of the present disclosure. Furthermore, the following embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Although the mechanism of action in the embodiments may be described below, the description of the mechanism of action includes an explanation based on speculation, and the present disclosure is not bound by the description of the mechanism of action.

[0011] 1. Overview The polyester polyol according to the embodiment (hereinafter also referred to as polyester polyol (A)) contains a polycarboxylic acid residue and a polyhydric alcohol residue. The polycarboxylic acid residue contains a 2,6-naphthalenedicarboxylic acid residue. Due to this configuration, the polyester polyol (A) according to the embodiment can produce a reaction product with improved solvent resistance.

[0012] In the present disclosure, the polycarboxylic acid residue refers to a moiety obtained by removing OH from a carboxy group of a polycarboxylic acid represented by formula (1). 1 is a substituted or unsubstituted hydrocarbon group having 1 to 50 carbon atoms.

[0013] [ka]

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

[0015] [ka]

[0016] In the formulas (1) and (2), * indicates a group adjacent to the residue represented by formula (1) or (2) or a bonding site to the adjacent residue.

[0017] The polyester polyol (A) is particularly suitable for use in producing a polyurethane resin, and therefore the reaction product according to this 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 (Solubility) The polyester polyol (A) has enhanced solubility in commonly used organic solvents. In particular, the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents is easily enhanced. In this case, the polyester polyol (A) can be efficiently reacted with a compound capable of reacting with the hydroxyl group of the polyester polyol (A) using a non-halogenated solvent and a non-pyrrolidone solvent. In other words, the use of the polyester polyol (A) according to the embodiment has the advantage that various reaction products can be produced from the polyester polyol (A) without using solvents that have a large environmental impact, such as halogenated solvents and pyrrolidone solvents.

[0020] The above-mentioned properties of the polyester polyol (A) can be achieved by appropriately adjusting the polycarboxylic acid residues and polyhydric alcohol residues contained in the polyester polyol (A) within the ranges explained below.

[0021] 2.2 Composition (polycarboxylic acid residue) As described above, the polyester polyol (A) contains a polycarboxylic acid residue. The polycarboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue. The proportion of the 2,6-naphthalenedicarboxylic acid residue relative to the total polycarboxylic acid residues contained in the polyester polyol (A) is preferably 30 mol% or more and 80 mol% or less. A proportion of 30 mol% or more can further enhance the solvent resistance of the reaction product produced from the polyester polyol (A). A proportion of 80 mol% or less can facilitate enhancing the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents. This proportion is preferably 35 mol% or more, more preferably 45 mol% or more. This proportion is more preferably 75 mol% or less, even more preferably 70 mol% or less.

[0022] Furthermore, the polycarboxylic acid residue includes, in addition to a 2,6-naphthalenedicarboxylic acid residue, at least one selected from the group consisting of an aromatic dicarboxylic acid residue other than a 2,6-naphthalenedicarboxylic acid residue and an aliphatic dicarboxylic acid residue. The aromatic dicarboxylic acid residue other than a 2,6-naphthalenedicarboxylic acid residue includes, for example, at least one selected from the group consisting of a terephthalic acid residue, an isophthalic acid residue, an orthophthalic acid residue, a diphenic acid residue, a naphthalic acid residue, a 1,2-naphthalenedicarboxylic acid residue, a 1,4-naphthalenedicarboxylic acid residue, a 1,5-naphthalenedicarboxylic acid residue, and a 2,7-naphthalenedicarboxylic acid residue.

[0023] The polycarboxylic acid residues preferably further include 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 the polyester polyol (A) can be further improved. The total proportion of terephthalic acid residues and isophthalic acid residues relative to the total polycarboxylic acid residues contained in the polyester polyol (A) is preferably 20 mol% or more and 70 mol% or less. A proportion of 20 mol% or more can further improve the solvent resistance of the reaction product produced from the polyester polyol (A). A proportion of 70 mol% or less can further increase the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents. This proportion is more preferably 25 mol% or more, and even more preferably 35 mol% or more. This proportion is more preferably 65 mol% or less, and even more preferably 55 mol% or less.

[0024] Furthermore, 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 the polyester polyol (A) is preferably 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 the 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 is preferable that the polycarboxylic acid residues do not contain orthophthalic acid residues, as this may result in the by-production of orthophthalic acid esters, which are of concern for their harmfulness.

[0025] The aliphatic dicarboxylic acid residue includes at least one selected from the group consisting of oxalic acid residue, malonic acid residue, succinic acid residue, maleic acid residue, fumaric acid residue, itaconic acid residue, glutaric acid residue, adipic acid residue, pimelic acid residue, 2,2-dimethylglutaric acid residue, suberic acid residue, azelaic acid residue, sebacic acid residue, dodecanedioic acid residue, 1,3-cyclopentanedicarboxylic acid residue, 1,4-cyclohexanedicarboxylic acid residue, diglycolic acid residue, and thiodipropionic acid residue. The proportion of aliphatic dicarboxylic acid residues relative to the total polycarboxylic acid residues contained in the polyester polyol (A) is preferably 50 mol % or less, which facilitates enhancing the solvent resistance of the reaction product produced from the polyester polyol (A).

[0026] Furthermore, from the viewpoint of adjusting the glass transition temperature (Tg), the aliphatic dicarboxylic acid residue may contain a linear or branched chain polycarboxylic acid residue having 2 or more and 10 or less carbon atoms, excluding the carbon atoms of the carboxy group. Having 2 or more carbon atoms facilitates lowering the glass transition temperature (Tg) of the polyester polyol (A). Furthermore, solubility in non-halogenated solvents and non-pyrrolidone solvents is facilitated. Having 10 or less carbon atoms facilitates improving the solvent resistance of a reaction product produced from the polyester polyol (A). Preferably, the carbon number is 8 or less. Specifically, the linear polycarboxylic acid residue contains at least one selected from the group consisting of succinic acid residue, adipic acid residue, azelaic acid residue, sebacic acid residue, and dodecanedioic acid residue. Furthermore, the proportion of the linear polycarboxylic acid residue relative to all polycarboxylic acid residues contained in the polyester polyol (A) is preferably 0 mol % or more and 50 mol % or less. If this proportion is 50 mol % or less, the solvent resistance of the reaction product produced from the polyester polyol (A) can be easily improved. This proportion is more preferably 40 mol % or less, and even more preferably 30 mol % or less.

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

[0028] (polyhydric alcohol residue) As described above, the polyester polyol (A) contains a polyhydric alcohol residue. The polyhydric alcohol residue may include at least one selected from the group consisting of ethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, polypropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Preferably, the polyhydric alcohol residue does not contain a bisphenol residue, which is considered to be harmful.

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

[0030] Furthermore, the proportion of linear polyhydric alcohol residues relative to the total polyhydric alcohol residues contained in the polyester polyol (A) is preferably 20 mol% or more and 70 mol% or less. A proportion of 20 mol% or more can easily increase the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents. A proportion of 70 mol% or less can improve the solvent resistance of the reaction product produced from the polyester polyol (A). 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, the polyhydric alcohol residue preferably does not contain a trihydric or higher polyhydric alcohol acid residue. In this case, the branched structure of the polyester polyol (A) can be reduced. Therefore, the solubility of the polyester polyol (A) in non-halogenated solvents and non-pyrrolidone solvents can be easily improved. The trihydric or higher polyhydric alcohol residue includes at least one selected from the group consisting of aliphatic triol residues such as glycerin residue, trimethylolpropane residue, and pentaerythritol residue; alicyclic triol residues such as 1,2,4-cyclohexanetrimethanol residue; and aromatic triol residues such as benzenetrimethanol residue. When the polyhydric alcohol residue contains a trihydric or higher polyhydric alcohol residue, the proportion of the trihydric or higher polyhydric alcohol residue relative to the total polyhydric alcohol residues contained in the polyester polyol (A) is preferably 10 mol% or less, more preferably 5 mol% or less.

[0032] It is particularly preferred that the polyester polyol (A) according to the embodiment does not contain a polycarboxylic acid residue having a valence of three or more and that the polyhydric alcohol residue does not contain a polyhydric alcohol acid residue having a valence of three or more, which makes it easier to particularly enhance the solubility of the polyester polyol (A) in non-halogen solvents and non-pyrrolidone solvents.

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

[0034] (acid number) 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 acid value of the polyester polyol (A) is preferably as small as possible, and may be 0 mg KOH / g. In the present disclosure, the acid value refers to the number of milligrams of potassium hydroxide required to neutralize 1 g of a sample such as the polyester polyol (A).

[0035] (Hydroxyl value) The hydroxyl value of the polyester polyol (A) according to the present invention is preferably 18 mgKOH / g or more and 225 mgKOH / g or less. A hydroxyl value of 18 mgKOH / g or more allows the polyester polyol (A) to react more efficiently with an isocyanate compound. A hydroxyl value of 225 mgKOH / g or less allows the proportion of the polyester polyol (A) skeleton contained in the polyurethane resin (B) to be increased. This allows the solvent resistance of the polyurethane resin (B) produced from the polyester polyol (A) to be further improved. The hydroxyl value is more preferably 25 mgKOH / g or more, and even more preferably 35 mgKOH / g or more. The hydroxyl value is more preferably 170 mgKOH / g or less, and even more preferably 130 mgKOH / g or less. The hydroxyl value in the present disclosure refers to the number of milligrams of potassium hydroxide required to neutralize acetic acid bonded to hydroxyl groups 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 present embodiment is, for example, 500 or more and 6200 or less. When the number average molecular weight is within the above range, the polyester polyol (A) can react with isocyanate more efficiently, 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. The number average molecular weight of the polyester polyol (A) in the present disclosure 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. When the Tg of the polyester polyol (A) is 10°C or higher, the reaction product produced from the polyester polyol (A) is less likely to develop excessive stickiness, resulting in better handleability and further suppressing the occurrence of tack. When the Tg of the polyester polyol (A) is 100°C or lower, the reaction product produced from the polyester polyol (A) has better film-forming properties, and the adhesion to substrates and primer properties are further improved. The Tg of the polyester polyol (A) is more preferably 20°C or higher, and even more preferably 30°C or higher. The Tg of the 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 a polyester polyol (A) according to an embodiment will now be described. The polyester polyol (A) can be produced by polycondensing a monomer component containing a polycarboxylic acid component and a polyhydric alcohol component. For example, when the polycarboxylic acid component is a polycarboxylic acid and the polyhydric alcohol component is a polyhydric alcohol, a direct esterification reaction can be employed in which the polycarboxylic acid and the polyhydric alcohol are reacted in a single reaction. When the polycarboxylic acid component is an ester-forming derivative of a polycarboxylic acid, such as a terephthalic acid ester, and the polyhydric alcohol component is a polyhydric alcohol, the polyester polyol (A) can be produced through a first-stage reaction, which is a transesterification reaction between the ester-forming derivative of the polycarboxylic acid and the polyhydric alcohol, and a second-stage reaction, in which the reaction product from the first-stage reaction is polycondensed. The raw materials used to produce the polyester polyol (A) may be added to the reaction system in stages, or all raw materials may be present from the beginning.

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

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

[0041] Subsequently, the second-stage reaction, that is, the polycondensation reaction, is carried out under the following reaction conditions: for example, a reduced pressure of 6.7 hPa (5 mmHg) or less, and a temperature range of 150 to 260°C.

[0042] A catalyst may be used in the first and second stage reactions, and the catalyst may contain at least one selected from the group consisting of titanium, antimony, lead, zinc, magnesium, calcium, manganese, and alkali metal compounds.

[0043] The polyester polyol (A) according to the embodiment can be produced by the method described above. Note that the above-mentioned methods are merely examples, and the production method is not particularly limited as long as the polyester polyol (A) according to the embodiment can be produced.

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

[0045] The polyester polyol (A) can be used as a reactant for producing various reaction products, in which case reaction products with increased solvent resistance can be produced from the polyester polyol (A).

[0046] For example, the reaction product can be obtained by reacting a polyester polyol (A) with a compound capable of reacting with the hydroxyl groups of the polyester polyol (A). The compound capable of reacting with the hydroxyl groups of the polyester polyol (A) is not particularly limited, but an isocyanate compound is preferably used. That is, 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 the 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 produced from the polyester polyol (A) having the composition and physical properties described above, which enhances the adhesion of the polyurethane resin (B) to the PET substrate.

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

[0051] In this way, the polyurethane resin (B) according to this embodiment can simultaneously achieve improvements in 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 reacting the polyester polyol (A) with an isocyanate compound. That is, the polyurethane resin (B) may contain a reaction product of the polyester polyol (A) with an isocyanate compound.

[0054] The isocyanate compound includes, for example, at least one selected from the group consisting of an aliphatic isocyanate compound, an alicyclic isocyanate compound, an aromatic isocyanate compound, and an araliphatic isocyanate compound. 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. The alicyclic isocyanate compound includes at least one selected from the group consisting of, for example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-cyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, etc. The aromatic isocyanate compound includes at least one selected from the group consisting of, for example, tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, etc. The araliphatic isocyanate compound includes, for example, at least one selected from the group consisting of alkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and the like.

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

[0056] The specific procedure for producing the polyurethane resin (B) is as follows.

[0057] First, a mixture containing polyester polyol (A) and a solvent is placed in a reaction vessel, and then the mixture is stirred under an inert gas atmosphere such as nitrogen gas and normal pressure conditions while gradually increasing the temperature to dissolve polyester polyol (A) in the solvent. Next, an isocyanate compound is added to the solution held in the reaction vessel, and the solution is stirred within a temperature range of 60 to 90°C to allow the urethanization reaction to proceed.

[0058] In this way, polyurethane resin (B) can be produced. Note that the production methods listed above are merely examples, and the production method is not particularly limited as long as polyurethane resin (B) can be produced.

[0059] The solvent used in producing the polyurethane resin (B) is not particularly limited, but is preferably a solvent that does not react with an isocyanate compound. 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 the solvent. Therefore, when producing the polyurethane resin (B) according to the embodiment, at least one solvent 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] A catalyst may be used in producing the polyurethane resin (B), including 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-described production method is recovered in a dissolved state in the solvent used during the reaction, and the solution containing the polyurethane resin (B) can be used directly for various applications. In other words, the above-described production method allows a polyurethane resin composition containing the polyurethane resin (B) to be obtained, which can be used for various applications. For example, the polyurethane resin composition can be used to produce a molded product, an adhesive, or a coating film for coating a plastic film. Alternatively, the polyurethane resin composition can be produced by extracting only the polyurethane resin (B) from the solution used to produce the polyurethane resin (B) and then adding a solvent or the like to the polyurethane resin (B).

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

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

[0064] For example, the additive includes at least one selected from the group consisting of a neutralizing agent, a chain extender, and the like.

[0065] The neutralizing agent neutralizes the reaction product formed by the reaction of the polyester polyol (A) with the isocyanate compound, thereby making it easier to disperse the polyurethane resin (B) in water. Examples of the neutralizing agent include 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 an isocyanate group. For example, if the reaction product formed by the reaction of polyester polyol (A) with an isocyanate compound contains an isocyanate group, the isocyanate group can react with the chain extender. This allows the reaction products formed by the reaction of polyester polyol (A) with the isocyanate compound to be bonded together via the chain extender. As a result, the molecular weight of the polyurethane resin (B) can be increased. Examples of chain extenders include dimethylolalkanoic acids 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-butanediol. The diamine contains at least one selected from the group consisting of glycols such as diols, 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] The polyurethane resin water dispersion may contain water. For example, water can be added to a solution containing a reaction product of the polyester polyol (A) and an isocyanate compound during the production process of the polyurethane water dispersion.

[0068] Specifically, the polyurethane resin aqueous dispersion is produced by the following method.

[0069] First, a mixture containing polyester polyol (A) and a solvent is placed in a reaction vessel, and then the mixture is stirred under an inert gas atmosphere such as nitrogen gas and normal pressure conditions while gradually increasing the temperature to dissolve polyester polyol (A) in the solvent. Next, an isocyanate compound is added to the solution held in the reaction vessel, and the solution is stirred within a temperature range of 60 to 90°C to allow the urethanization reaction to proceed.

[0070] The solution is then cooled and neutralized by adding a neutralizing agent. Water is then added to the neutralized solution to disperse the reaction product of the polyester polyol (A) and the isocyanate compound in water. The solvent used in the reaction of the polyester polyol (A) and the isocyanate compound is then distilled off under reduced pressure.

[0071] The polyurethane resin aqueous dispersion can be produced by the above procedure. Note that the reaction may be carried out by adding a chain extender after adding the neutralizing agent and water, and then the solvent used in the reaction of the polyester polyol (A), the isocyanate compound, and the chain extender may be distilled off under reduced pressure.

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

[0073] 4. Aspects The polyester polyol (A) according to the first aspect of the present disclosure contains a polycarboxylic acid residue and a polyhydric alcohol residue. The polycarboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue.

[0074] According to this embodiment, it is possible to provide a polyester polyol (A) that can produce a reaction product with improved solvent resistance.

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

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

[0077] The polyester polyol (A) according to the fourth aspect is the polyester polyol (A) according to the third aspect, wherein the total ratio of terephthalic acid residues and isophthalic acid residues to the total polyvalent carboxylic 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 a fifth aspect, in any one of the first to fourth aspects, has a hydroxyl value of 18 mgKOH / g or more and 225 mgKOH / g or less.

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

[0080] The polyester polyol (A) according to the seventh aspect is any one of the first to sixth aspects, in which the polyvalent carboxylic acid residue does not contain a trivalent or higher polyvalent carboxylic acid residue, or the polyhydric alcohol residue does not contain a trivalent or higher polyhydric alcohol residue.

[0081] The polyester polyol (A) according to an eighth aspect is any one of the first to seventh aspects, wherein the polyhydric alcohol residue includes a chain polyhydric alcohol residue having a linear or branched chain having 3 to 6 carbon atoms.

[0082] The polyester polyol (A) according to a ninth aspect is the polyester polyol (A) of the eighth aspect, in which the proportion of chain 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 aspect is used to synthesize the polyurethane resin (B) in any one of the first to ninth aspects.

[0084] The polyurethane resin (B) according to the eleventh aspect includes a reaction product of the polyester polyol (A) according to any one of the first to tenth aspects and an isocyanate compound.

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

[0086] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0087] 1. Polyester polyol 1.1 Synthesis of polyester polyol According to the list of reaction raw materials listed in Table 1, a 1000 ml reaction vessel equipped with a stirrer, nitrogen gas inlet, thermometer, rectification column, and condenser was charged with the catalyst potassium titanium oxalate and the components listed under "polycarboxylic acid component" and "polyhydric alcohol component" in the "reaction raw material" column, so that their total mass was "total charged amount / g." The molar ratio of polycarboxylic acid component to polyhydric alcohol component was 1:2. The mixture was heated to 190°C under atmospheric pressure with stirring in a nitrogen atmosphere, and then gradually heated to 240°C over 6.5 hours to allow the transesterification reaction to proceed. Next, the mixture was cooled to 170-205°C while stirring in the reaction vessel. At that temperature, the pressure was gradually reduced from atmospheric pressure to 0.67 hPa (0.5 mmHg), and the mixture was maintained at this temperature for 4 hours to allow the polycondensation reaction to proceed. This resulted in the production of a polyester polyol.

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

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

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

[0091] (glass transition temperature) The glass transition temperature of the polyester polyol was determined from the measurement results of differential scanning calorimetry using a differential scanning calorimeter (DSCvesta manufactured by Rigaku Corporation) in accordance with JIS K 7121:2012.

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

[0093] 1.3 Evaluation The polyester polyol was evaluated, and the results are shown in Table 1.

[0094] (Solubility) The obtained polyester polyol was added to a glass bottle (225 mL) containing each of the solvents shown in Table 1 in a proportion of 50% by mass, and dissolved under stirring for 1 hour at 60° C. or 70° C. The appearance of the solution containing the dissolved polyester polyol was evaluated according to the following criteria, and the results are shown in Table 1. A: The solution is not cloudy. B: The solution is cloudy. C: Some undissolved material is visible.

[0095] [Table 1]

[0096] 2. Polyurethane resin composition 2.1 Synthesis of polyurethane resin composition According to the reaction raw materials and solvents listed in Table 2, the polyester polyol shown 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 achieve a uniform mixture. Next, an isocyanate compound was added, and the mixture was reacted at 80°C for 6 hours, after which ethanol was added to quench the mixture, yielding 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 measurement by gel permeation chromatography (polystyrene equivalent). The measurement conditions are shown below. Equipment: Shodex SYSTEM 11 manufactured by Resonac Column: Resonac Shodex GPC KF-805, 3 columns in total Guard column: Shodex GPC KF-G 4A, manufactured by Resonac Sample concentration: Dilute with tetrahydrofuran so that the polyurethane resin concentration becomes 0.5% by mass. Mobile phase solvent: tetrahydrofuran ·Flow rate: 1mL / min Detector: Differential refractive index detector Column temperature: 40℃

[0100] (number average molecular weight) The number average molecular weight of the polyurethane resin was determined from the results of measurement by 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 the polyurethane resin was determined from the measurement results by differential scanning calorimetry using a differential scanning calorimeter (DSCvesta manufactured by Rigaku Corporation) in accordance with JIS K 7121:2012.

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

[0103] 2.3 Evaluation The polyurethane resin composition was evaluated, and the results are shown in Table 2.

[0104] (Solvent resistance) The polyurethane resin composition was applied to a PET substrate (trade name "Lumirror T60#25", manufactured by Toray Industries, Inc.) to a film thickness of 3 μm, and then dried at 120° C. for 5 minutes to produce a coating film. The surface of this coating film was rubbed 10 times with a cotton swab soaked in each of the solvents shown in Table 2, and then 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 change was observed on the coating surface. B: Part of the coating surface turns white or dissolves. C: Most of the coating surface turns white or dissolves.

[0105] (adhesion) The polyurethane resin composition was applied to a PET substrate (trade name "Lumirror T60#25", manufactured by Toray Industries, Inc.) to a film thickness of 3 μm, and then dried for 5 minutes at 120° C. to produce a coating film. Cellotape (registered trademark) manufactured by Nichiban was applied to this coating film and then quickly peeled off, and the presence or absence of peeling of the film was checked and evaluated according to the following criteria. A: No peeling was observed on the coating. B: Peeling was observed in part of the coating film, or transfer of the coating film was observed in part of the cellophane tape surface. C: Peeling was observed on most of the coating film, or transfer of the coating film was observed on most of the cellophane tape surface.

[0106] (tackiness) As in the case of the above (adhesion), a coating film was prepared on a PET film, and the polyurethane resin composition was applied to a PET substrate (trade 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 a coating film. An unused identical PET substrate was placed on top of the coating film, and a coating of 500 g / cm was applied from above. 2 After applying a load of 1.000 psi and maintaining the sample at 20° C. for 12 hours, the PET substrate was peeled off and the tackiness was evaluated according to the following criteria. A: No resistance is felt when peeling off the PET substrate. B: A slight resistance is felt when peeling off the PET substrate. C: Resistance is felt when peeling off the PET substrate.

[0107] [Table 2]

[0108] 3. Polyurethane resin water dispersion 3.1 Synthesis of polyurethane resin aqueous dispersion According to the reaction raw materials and solvents listed in Table 3, the polyester polyol shown 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 stirred at 75°C for 1 hour to achieve uniform mixing and dissolution. An isocyanate compound was then added, and the mixture was allowed to react with stirring at 75°C for 3 hours to obtain a reaction solution containing a polyurethane resin. This reaction solution was then cooled to 35°C, and neutralized by adding triethylamine as a neutralizing agent. Water was then gradually added to disperse the polyurethane resin in water. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a polyurethane resin aqueous dispersion.

[0109] In Comparative Example 4, polypropylene glycol (number average molecular weight 1000) was used in place 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. 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 measurement by gel permeation chromatography (polystyrene equivalent). The measurement conditions are shown below. Equipment: Shodex SYSTEM 11 manufactured by Resonac Column: Resonac Shodex GPC KF-805, 3 columns in total Guard column: Shodex GPC KF-G 4A, manufactured by Resonac Sample concentration: Dilute with tetrahydrofuran so that the polyurethane resin concentration becomes 0.5% by mass. Mobile phase solvent: tetrahydrofuran ·Flow rate: 1mL / min Detector: Differential refractive index detector Column temperature: 40℃

[0112] (number average molecular weight) The number average molecular weight of the polyurethane resin was determined from the results of measurement by 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 the polyurethane resin was determined from the measurement results by differential scanning calorimetry using a differential scanning calorimeter (DSCvesta manufactured by Rigaku Corporation) in accordance with JIS K 7121:2012.

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

[0115] 3.3 Evaluation The polyurethane resin aqueous dispersion was evaluated, and the results are shown in Table 3.

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

[0117] (adhesion) A coating film was produced by applying the polyurethane resin aqueous dispersion to a PET substrate (trade name "Lumirror T60#25", manufactured by Toray Industries, Inc.) to a film thickness of 3 μm and drying for 10 minutes at 120° C. Cellotape (registered trademark) manufactured by Nichiban was applied to the coating film and then forcefully peeled off, and the film was checked for peeling and evaluated according to the following criteria. A: No peeling was observed on the coating. B: Peeling was observed in part of the coating film, or transfer of the coating film was observed in part of the cellophane tape surface. C: Peeling was observed on most of the coating film, or transfer of the coating film was observed on most of the cellophane tape surface.

[0118] (tackiness) As in the case of the above (adhesion), a coating film was prepared on a PET film, and the polyurethane resin composition was applied to a PET substrate (trade name "Lumirror T60#25", manufactured by Toray Industries, Inc.) to a film thickness of 3 μm, and dried at 120° C. for 10 minutes to prepare a coating film. An unused identical PET substrate was placed on top of the coating film, and 500 g / cm 2 After applying a load of 1.000 psi and maintaining the sample at 20° C. for 12 hours, the PET substrate was peeled off and the tackiness was evaluated according to the following criteria. A: No resistance is felt when peeling off the PET substrate. B: A slight resistance is felt when peeling off the PET substrate. C: Resistance is felt when peeling off the PET substrate.

[0119] [Table 3]

Claims

1. Contains a polycarboxylic acid residue and a polyhydric alcohol residue, the polycarboxylic acid residue includes a 2,6-naphthalenedicarboxylic acid residue; Polyester polyol.

2. a ratio of the 2,6-naphthalenedicarboxylic acid residue to the total polycarboxylic acid residues contained in the polyester polyol is 30 mol % or more and 80 mol % or less; The polyester polyol according to claim 1 .

3. The polycarboxylic acid residue further includes at least one selected from the group consisting of a terephthalic acid residue and an isophthalic acid residue. The polyester polyol according to claim 1 .

4. a total ratio of the terephthalic acid residues and the isophthalic acid residues to the total polycarboxylic acid residues contained in the polyester polyol is 20 mol % or more and 70 mol % or less; The polyester polyol according to claim 3 .

5. The hydroxyl value is 18 mgKOH / g or more and 225 mgKOH / g or less. The polyester polyol according to claim 1 .

6. The glass transition temperature is 10°C or higher and 100°C or lower. The polyester polyol according to claim 1 .

7. the polycarboxylic acid residue does not contain a trivalent or higher polycarboxylic acid residue, or the polyhydric alcohol residue does not contain a trivalent or higher polyhydric alcohol residue; The polyester polyol according to claim 1 .

8. The polyhydric alcohol residue includes a linear or branched chain polyhydric alcohol residue having 3 to 6 carbon atoms. The polyester polyol according to claim 1 .

9. a ratio of the chain polyhydric alcohol residue to the total polyhydric alcohol residues contained in the polyester polyol is 20 mol % or more and 70 mol % or less; The polyester polyol according to claim 8.

10. Used to synthesize polyurethane resins, The polyester polyol according to claim 1 .

11. A reaction product of the polyester polyol according to any one of claims 1 to 10 and an isocyanate compound. Polyurethane resin.

12. A method for producing a polyester polyol comprising reacting a hydroxyl group of the polyester polyol according to any one of claims 1 to 10 with an isocyanate group of an isocyanate compound, A method for producing polyurethane resin.

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