JP7480925B1 - 1,6-Hexanediol composition, polymer, curable resin composition and coating material - Google Patents

Abstract

The present invention aims to provide a 1,6-hexanediol composition which, in a thermosetting resin composition, can extend the pot life without causing poor curing, and which, in an oxidative polymerization type curable resin composition, can maintain the curing (drying) time without delay even without blending a curing accelerator or even if the blending amount is reduced, as well as a polymer, a curable resin composition, and a coating material using the same. The present invention also relates to a 1,6-hexanediol composition which contains either one or both of 1,6-hexanediol and a 1,6-hexanediol derivative, and an alkali metal element, and in which the total content of the alkali metal element relative to the total amount of the composition is in the range of 1 to 5,000 ppm by mass.

Description

The present invention relates to a 1,6-hexanediol composition, a polymer, a curable resin composition and a coating material.

1,6-Hexanediol (1,6-HD) compositions are useful intermediates for the production of polymers such as polyesters, polyurethanes, and the like. 1,6-Hexanediol compositions can generally be produced by (1) hydrogenation of adipic acid or an adipic acid-containing feed stream, (2) hydrogenation of hydroxycaproic acid or its esters, or (3) hydrogenation of caprolactone.

Applications of the polymer obtained by reacting the 1,6-hexanediol composition include paints, adhesives, etc. (for example, Patent Document 1).

JP 2020-196900 A

The present invention aims to provide a 1,6-hexanediol composition, a polymer, a curable resin composition, and a coating material that, when used as a thermosetting resin composition, can extend the pot life without causing poor curing. Another object of the present invention is to provide a 1,6-hexanediol composition, a polymer, a curable resin composition, and a coating material that, when used as an oxidative polymerization type curable resin composition, can maintain the curing (drying) time without delay even without blending a curing accelerator or even if the blending amount is reduced.
In this specification, the pot life means the usable time of the mixture, for example, the time until the thermosetting resin composition gels at 50°C.

As a result of intensive research, the present inventors have found that in a thermosetting resin composition containing a polymer such as a polyester, which is made from a 1,6-hexanediol composition containing a specific amount of an alkali metal element as a reaction raw material, the pot life can be extended without causing curing failure, and have completed the present invention. In addition, in an oxidative polymerization type curable resin composition containing the polymer, the curing (drying) time can be maintained without delay even without blending a curing accelerator or by reducing the blending amount, and have completed the present invention.
Furthermore, the present inventors have found that the trihydric or tetrahydric alcohol in the 1,6-hexanediol composition of the present invention affects the pot life of the thermosetting resin composition and, in some cases, affects the synthesis of polymers such as polyesters.

That is, the present invention provides the following inventions.
[1] A 1,6-hexanediol composition containing 1,6-hexanediol, a 1,6-hexanediol derivative, or both, and an alkali metal element, wherein the total content of the alkali metal element relative to the total amount of the composition is in the range of 1 to 5,000 ppm by mass.

[2] A 1,6-hexanediol composition of [1] further containing a trihydric or tetrahydric alcohol, wherein the content of the alcohol relative to the total amount of the 1,6-hexanediol composition is in the range of 0.1 to 2,000 ppm by mass.

[3] A 1,6-hexanediol composition of [2], wherein the alcohol is a trihydric aliphatic alcohol.

[4] A 1,6-hexanediol composition of [3], wherein the alcohol is glycerin.

[5] A 1,6-hexanediol composition according to any of [1] to [4], characterized in that the 1,6-hexanediol composition is derived from a biomass resource.

[6] A polymer using any of the 1,6-hexanediol compositions [1] to [5] as a reaction raw material.

[7] A polymer of [5], wherein the polymer is a polyester.

[8] A curable resin composition containing a polymer of [5] or [6].

[9] A paint containing the curable resin composition described in [8].

The 1,6-hexanediol composition of the present invention has a total alkali metal element content of 1 to 5,000 ppm by mass, so that in a thermosetting resin composition containing a polymer such as a polyester obtained by reacting the 1,6-hexanediol composition, the pot life can be extended without causing poor curing, and in an oxidative polymerization type curable resin composition containing the polymer, the curing (drying) time can be maintained without delay even without blending a curing accelerator or by reducing the amount of the accelerator blended.

<1,6-Hexanediol Composition>
The 1,6-hexanediol composition of the present invention (hereinafter, may be simply referred to as the composition) contains either one or both of 1,6-hexanediol and a 1,6-hexanediol derivative, and an alkali metal element, and the total content of the alkali metal elements relative to the total amount of the composition is in the range of 1 to 5,000 ppm by mass.

<<1,6-Hexanediol and 1,6-Hexanediol Derivatives>>
The 1,6-hexanediol contained in the composition of the present invention is preferably unmodified 1,6-hexanediol, but may be a 1,6-hexanediol derivative. That is, the composition of the present invention contains at least one of 1,6-hexanediol and a 1,6-hexanediol derivative.

The 1,6-hexanediol derivative contained in the composition of the present invention is a compound in which one or both of the two hydroxyl groups of the 1,6-hexanediol contained in the 1,6-hexanediol composition of the present invention have been modified. Here, as a method for modifying the hydroxyl groups of 1,6-hexanediol, a known method for modifying a hydroxyl group can be used, such as an etherification reaction, an esterification reaction, modification with (meth)acrylic acid, etc.

Examples of the 1,6-hexanediol derivatives include epoxy group-containing 1,6-hexanediol derivatives such as 1,6-hexanediol diglycidyl ether and 6-hydroxyhexyl glycidyl ether; (meth)acryloyl group-containing 1,6-hexanediol derivatives such as 1,6-hexanediol di(meth)acrylate, 6-hydroxyhexyl acrylate, and 1,6-hexanediol monoacrylate monomethacrylate; vinyl ether group-containing 1,6-hexanediol derivatives such as 1,6-hexanediol divinyl ether and 1,6-hexanediol monovinyl ether; aliphatic alkyl ether group-containing 1,6-hexanediol derivatives such as 6-propyloxy-1-hexanol, 1,6-dipropoxy-hexane, 1,6-hexanediol methyl ether, and 1,6-dimethoxyhexane; fatty acid ester group-containing 1,6-hexanediol derivatives such as propyl 6-hydroxyhexanoate, di-n-propyl adipate, methyl 6-hydroxycaproate, and dimethyl adipate. These may be used alone or in combination of two or more.

In this specification, a (meth)acryloyl group means either or both of an acryloyl group and a methacryloyl group, and a (meth)acrylate means either or both of an acrylate and a methacrylate.

In the composition of the present invention, the total content of either one or both of 1,6-hexanediol and 1,6-hexanediol derivatives is preferably 95.00 to 99.99 mass%, more preferably 96.00 to 99.99 mass%, and even more preferably 99.00 to 99.99 mass%. By keeping the total content of alkali metal elements and, if necessary, the content of trihydric or tetrahydric alcohol within the above ranges and the purity of the 1,6-hexanediol composition within the above ranges, the effects of the present invention tend to be more favorably obtained.
In this specification, the total content of either or both of 1,6-hexanediol and 1,6-hexanediol derivatives is a value measured by gas chromatography mass spectrometry (GC-MS).

<<Alkali metal elements>>
The alkali metal element contained in the composition of the present invention is not particularly limited, and examples thereof include lithium, sodium, potassium, rubidium, cesium, etc. These may be used alone or in combination of two or more. Among these, sodium and potassium are preferred.

The state of the alkali metal element contained in the composition of the present invention is not particularly limited, and may be an alkali metal element, an alkali metal compound, an alkali metal ion, or the like.
Specific examples of the alkali metal compound include metal salts of the above alkali metal elements and acids such as acetic acid, phosphoric acid, and nitric acid.

In the 1,6-hexanediol composition of the present invention, the upper limit of the total content of alkali metal elements (preferably the total content of either or both of sodium metal element and potassium metal element) is preferably 5,000 mass ppm or less. The lower limit of the total content is not particularly limited, and is preferably 1 mass ppm or more, more preferably 100 mass ppm or more, even more preferably 500 mass ppm or more, and particularly preferably 800 mass ppm or more. Any combination of these upper and lower limits can be used.
In the 1,6-hexanediol composition of the present invention, the total content of alkali metal elements (preferably the total content of sodium metal element and potassium metal element) is 1 to 5,000 ppm by mass, preferably 100 to 5,000 ppm by mass, more preferably 500 to 5,000 ppm by mass, and even more preferably 800 to 5,000 ppm by mass. If the total content of alkali metals is within the above range, the above-mentioned effects are exhibited, and in a curable resin composition using a polymer such as a polyester obtained by reacting the 1,6-hexanediol composition, the curing (drying) property is good.
In this specification, the total content of alkali metals is a value measured by inductively coupled plasma mass spectrometry (ICP-MS).

<<Trihydric or tetrahydric alcohol>>
The composition of the present invention may further contain a trihydric or tetrahydric alcohol. Specific examples of the trihydric or tetrahydric alcohol include pentaerythritol, hexane tetrol, 2,-bis(hydroxymethyl)-1,3-propanediol (pentaerythritol), benzenetriol, 3-methylpentane-1,3,5-triol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and the like. Examples of the hydroxyethyl ether include 1,2,3-butanetriol, 1,2,4-butanetriol, 2-hydroxymethyl-2-methyl-1,3-propanediol (trimethylolethane), 2-ethyl-2-hydroxymethyl-1,3-propanediol (trimethylolpropane), 3-hydroxyethyl-3-methyl-1,5-pentanediol (triethylolethane), 3-ethyl-3-hydroxyethyl-1,5-pentanediol (triethylolpropane), etc. These may be used alone or in combination of two or more.
Among the above, trihydric aliphatic alcohols are more preferred, trihydric aliphatic alcohols having 3 to 10 carbon atoms are even more preferred, trihydric aliphatic alcohols having 3 to 8 carbon atoms are particularly preferred, and glycerin is the most preferred. By including these alcohols in the composition of the present invention, when a thermosetting resin composition containing a polymer made from the composition of the present invention as a raw material is prepared, the pot life can be extended without causing poor curing. Furthermore, when an oxidative polymerization type curable resin composition containing a polymer made from the composition of the present invention as a raw material is prepared, the curing (drying) time can be maintained without delay even without blending a curing accelerator or by reducing the blending amount.

In the 1,6-hexanediol composition of the present invention, the upper limit of the content of trihydric or tetrahydric alcohol is preferably 2,000 mass ppm or less. The lower limit of the content is not particularly limited, and is preferably 0.1 mass ppm or more, more preferably 10 mass ppm or more, even more preferably 100 mass ppm or more, and particularly preferably 500 mass ppm or more. Any combination of these upper and lower limits can be used. In other words, the content of trihydric or tetrahydric alcohol is preferably 0.1 to 2,000 mass ppm, more preferably 10 to 2,000 mass ppm, even more preferably 100 to 2,000 mass ppm, and particularly preferably 500 to 2,000 mass ppm.
When the content of the trihydric or tetrahydric alcohol is within the above range, when a 1,6-hexanediol composition is reacted to synthesize a polymer such as a polyester, the amount of branched structures of the polymer chain due to the trihydric or tetrahydric alcohol can be adjusted, and gelation can be suitably suppressed while obtaining the effects of the present invention.
In this specification, the content of trihydric or tetrahydric alcohol is a value measured by gas chromatography mass spectrometry (GC-MS).

The 1,6-hexanediol composition of the present invention may be produced so that the total content of alkali metal elements falls within the above range. For example, since a commercially available 1,6-hexanediol composition has a total alkali metal content of less than 1 ppm by mass, a commercially available 1,6-hexanediol composition may be produced so that the total alkali metal content falls within the above range by adding an acid such as acetic acid, phosphoric acid, or nitric acid and a metal salt of an alkali metal to the commercially available 1,6-hexanediol composition.
Similarly, since the content of trihydric or tetrahydric alcohol in commercially available 1,6-hexanediol compositions is less than 0.1 ppm by mass, a trihydric or tetrahydric alcohol may be added to the commercially available 1,6-hexanediol composition so that the content of the trihydric or tetrahydric alcohol falls within the above range.

The reason why the effect is exhibited in polymers such as polyesters obtained by reacting the 1,6-hexanediol composition and in curable resin compositions (particularly thermosetting resin compositions or oxidative polymerization type curable resin compositions) containing the above-mentioned polymers by setting the content of alkali metal elements contained in the composition of the present invention within the above-mentioned range is not clear, but is presumed to be as follows.

The thermosetting resin composition contains at least a base agent containing a polymer such as polyester, and a curing agent, and optionally further contains an acid curing catalyst such as a sulfonic acid-based catalyst. By containing an appropriate amount of alkali metal element (derived from the raw material 1,6-hexanediol composition) in the thermosetting resin composition, the acid curing catalyst is appropriately neutralized, and the pot life can be extended without causing poor curing.

In addition, by setting the content of trihydric or tetrahydric alcohol to 0.1 to 2,000 ppm by mass, the increase in the branching degree of polymers such as polyesters can be suppressed, making it possible to further extend the pot life.

In the oxidative polymerization type curable resin composition, a dryer such as cobalt, manganese, or iron is used for curing acceleration, but a curing acceleration assistant, so-called an auxiliary dryer, is also used in combination. The curing acceleration assistant includes metal salts (metal soaps) of at least one metal selected from the group consisting of alkali metals such as potassium and sodium, alkaline earth metals such as calcium and strontium, and heavy metals such as zirconium and lead, and various carboxylic acids.
On the other hand, when an alkali metal is contained in the 1,6-hexanediol composition, the alkali metal is also contained in a polymer such as a polyester obtained by reacting the 1,6-hexanediol composition, and in an oxidative polymerization type curable resin composition containing the polymer. Therefore, even if a curing accelerator is not blended or the blending amount is reduced, the curing (oxidative polymerization) reaction is accelerated, and the drying time can be maintained without delay.

<1,6-Hexanediol Composition Derived from Biomass Resources>
In recent years, environmental awareness has increased, and raw materials derived from biomass resources such as plants are desired, rather than petroleum-derived raw materials that affect global warming. Biomass resources are reusable organic resources derived from animals and plants, and preferred resources are plant resources such as wood, rice straw, rice husks, rice bran, old rice, corn, sugar cane, cassava, soybeans, soybean pulp, bagasse, vegetable oil, oils and fats, waste paper, and papermaking residues. These biomass resources generally contain many alkali metals and alkaline earth metals such as nitrogen elements, sodium, potassium, magnesium, and calcium. In addition, a method for obtaining raw materials derived from biomass resources using microorganisms such as Corynebacterium and Escherichia coli from biomass resources has also been disclosed, and in the present invention, for example, a 1,6-hexanediol composition derived from a biomass resource, such as a 1,6-hexanediol composition derived from a biomass resource obtained by the manufacturing method described in JP 2020-114227 A, can be suitably used. When fermentation by microorganisms is used, the hydrogen ion concentration (pH) of the fermentation liquid is usually adjusted by a neutralizing agent in order to efficiently proceed with fermentation. The neutralizing agent and culture liquid contain many alkali metals and alkaline earth metals. In addition, the inventors have found that 1,6-hexanediol derived from biomass resources obtained by the manufacturing method described in JP 2020-114227 A contains trihydric or tetrahydric alcohols as impurities as a result of intensive research. These impurities are considered unnecessary and are removed by utilizing a purification method as far as costs allow. However, the inventors have found that alkali metals are not unnecessary as a component to be coexisted with 1,6-hexanediol, and that the coexistence of a specific amount is rather an essential component for exerting the above-mentioned effect when a polymer such as a polyester obtained by reacting a 1,6-hexanediol composition is used in a curable resin composition. As for trihydric or tetrahydric alcohols, as described above, the inventors have found through extensive research that when a polymer such as a polyester obtained by reacting a 1,6-hexanediol composition is used in a curable resin composition, the pot life is not affected or shortened even if the impurities are not removed within a certain range. By combining known purification methods, a 1,6-hexanediol composition can be obtained in which the total content of alkali metals and the content of trihydric or tetrahydric alcohols are within the above ranges.

<Polymer>
The polymer of the present invention is obtained by reacting the 1,6-hexanediol composition of the present invention. The polymer is not particularly limited as long as it is a polymer having a structural unit derived from the 1,6-hexanediol composition of the present invention, and also includes oligomers. Examples of the polymer include polyester, polyurethane, polycarbonate, polyether, epoxy-based polymers made from the epoxy group-containing 1,6-hexanediol derivative as a raw material, and acrylic-based polymers made from the (meth)acryloyl group-containing 1,6-hexanediol derivative as a raw material. These may be used alone or in combination of two or more.
Among these, polyester, polyurethane, polycarbonate, and polyether are preferred, polyester, polyurethane, and polyether are more preferred, polyester and polyurethane are even more preferred, and polyester is particularly preferred, because the above-mentioned effects are more easily exhibited.
The polymer of the present invention has at least structural units derived from the 1,6-hexanediol composition of the present invention, contains an alkali metal derived from the 1,6-hexanediol composition, and further has structural units derived from a trihydric or tetrahydric alcohol, as necessary. Here, the trihydric or tetrahydric alcohol contained in the 1,6-hexanediol composition as necessary is incorporated into the polymer skeleton during polymerization.

The content of the structural unit derived from the 1,6-hexanediol composition of the present invention in 100% by mass of the polymer of the present invention is preferably 10 to 100% by mass, more preferably 20 to 100% by mass. This tends to make it possible to more suitably obtain the effects.
In this specification, the content of each structural unit in a polymer is measured by NMR.

In the polymer of the present invention, the total content of alkali metals (preferably the total content of either or both of sodium metal element and potassium metal element) is preferably 0.1 to 5,000 ppm by mass, more preferably 0.2 to 5,000 ppm by mass. This tends to make the effect more suitable.

The content of structural units derived from trihydric or tetrahydric alcohols in 100% by mass of the polymer of the present invention is preferably 0.01 to 2,000 ppm by mass, more preferably 0.02 to 2,000 ppm by mass. This tends to make the effect more suitable.

The polymer may be modified. The modification is not particularly limited, and examples include the modifications described for 1,6-hexanediol derivatives. These may be used alone or in combination of two or more. Of these, modification with (meth)acrylic acid is preferred. In particular, when the polymer is a polyester, modification with (meth)acrylic acid is preferred.

The weight average molecular weight (Mw) of the polymer of the present invention is preferably 2,000 to 1,000,000, and more preferably 3,000 to 50,000. In this specification, the weight average molecular weight (Mw) of the polymer is a value measured by gel permeation chromatography (GPC). In addition, when the polymer is a polyester, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) under the conditions described below.

In the following, we will explain in detail about polyester among the above polymers, but the above polymers are not limited to polyester.

<<Polyester>>
The polyester of the present invention is obtained by reacting the 1,6-hexanediol composition of the present invention.
Specifically, the polyester of the present invention is a polycondensate synthesized by dehydration condensation of a carboxylic acid and an alcohol to form an ester bond, and at least the 1,6-hexanediol composition of the present invention is used as the alcohol. Thus, the polyester of the present invention is a reaction product (polycondensate) obtained by a polycondensation reaction of a carboxylic acid and an alcohol, and the polyester of the present invention has at least a structural unit derived from the 1,6-hexanediol composition of the present invention, contains an alkali metal derived from the 1,6-hexanediol composition, and further has a structural unit derived from a trihydric or tetrahydric alcohol as necessary.

The polyester of the present invention is preferably a polyester polyol.
Examples of the polyester polyol include condensation polyester polyols and lactone polyester polyols. Condensation polyester polyols are, for example, reaction products of low molecular weight polyhydric alcohols (ethylene glycol (EG), diethylene glycol, propylene glycol (PG), dipropylene glycol, (1,3- or 1,4-)butanediol, pentanediol, neopentyl glycol, hexanediol, cyclohexanedimethanol, glycerin, 1,1,1-trimethylolpropane (TMP), 1,2,5-hexanetriol, pentaerythritol, 1,4-cyclohexanedimethanol, and other low molecular weight polyols, sorbitol, and other sugars) and polybasic carboxylic acids (glutaric acid, adipic acid, azelaic acid, fumaric acid, maleic acid, pimelic acid, suberic acid, sebacic acid, phthalic acid, terephthalic acid, isophthalic acid, dimer acid, pyromellitic acid, oligomer acid, hexahydrophthalic anhydride, 1,4-cyclohexanedicarboxylic acid, and the like). The lactone polyester polyol is, for example, a polycaprolactone polyol obtained by ring-opening polymerization of lactone such as ε-caprolactone, α-methyl-ε-caprolactone, or ε-methyl-ε-caprolactone.

Examples of the carboxylic acid include aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, pimelic acid, suberic acid, dodecanedicarboxylic acid, maleic acid, and fumaric acid; alicyclic polycarboxylic acids such as 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydrophthalic anhydride, and 1,4-cyclohexanedicarboxylic acid; orthophthalic acid, isophthalic acid, and terephthalic acid. , aromatic polycarboxylic acids such as naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and trimellitic acid; aliphatic monocarboxylic acids such as acetic acid, propionic acid, 2-ethylhexanoic acid, acrylic acid, and methacrylic acid; aromatic monocarboxylic acids such as benzoic acid, p-tertiary butyl benzoic acid, and p-hydroxybenzoic acid; fatty acids derived from various animal and vegetable oils such as soybean oil fatty acid, tall oil fatty acid, linoleic acid, and eicosapentaenoic acid; and anhydrides thereof. These may be used alone or in combination of two or more. Among these, aromatic polycarboxylic acids and their anhydrides, and fatty acids derived from animal and vegetable oils are preferred, and phthalic anhydride and soybean oil fatty acid are more preferred.

The alcohol that can be used in addition to the 1,6-hexanediol composition of the present invention is not particularly limited as long as it is a compound having a hydroxyl group (alcoholic hydroxyl group or phenolic hydroxyl group). Examples of the alcohol include aliphatic monoalcohols such as ethanol, butanol, and 2-ethylhexanol; aliphatic polyols such as ethylene glycol, neopentyl glycol, and trimethylolpropane; aromatic monohydric and polyhydric phenols such as phenol, cresol, and bisphenol-A; and ethylene oxide-extended products thereof, hydrogenated alicyclic alcohols, and the like. These may be used alone or in combination of two or more kinds. Among them, aliphatic polyols are preferred, and neopentyl glycol and trimethylolpropane are more preferred.

The content of the 1,6-hexanediol composition of the present invention in 100% by mass of the alcohol is preferably 1 to 100% by mass, more preferably 10 to 100% by mass. This tends to make the effect more favorable.

The polyester of the present invention can be obtained by a known polyester manufacturing method. Specifically, it can be synthesized by a manufacturing method in which the carboxylic acid and the alcohol are reacted at a reaction temperature of 150 to 280°C while removing the water produced from the system. In addition, a reaction catalyst, an antioxidant, etc. may be used in combination during the synthesis.

The content of the structural unit derived from the 1,6-hexanediol composition of the present invention in 100% by mass of the polyester of the present invention is preferably 10 to 70% by mass, more preferably 20 to 70% by mass. This tends to make it possible to more suitably obtain the effects.
In this specification, the content of each structural unit in the polyester is measured by NMR.

In the polyester of the present invention, the total content of alkali metal elements (preferably the total content of either or both of sodium metal element and potassium metal element) is preferably 0.1 to 3,500 ppm by mass, more preferably 0.2 to 3,500 ppm by mass. This tends to make the effect more suitable.

The content of structural units derived from trihydric or tetrahydric alcohols in 100% by mass of the polyester of the present invention is preferably 0.01 to 1,400 ppm by mass, more preferably 0.02 to 1,400 ppm by mass. This tends to make the effect more suitable.

The weight average molecular weight (Mw) of the polyester of the present invention is preferably 2,000 to 120,000, and more preferably 3,000 to 50,000.

The polymer of the present invention can be used in a wide range of applications, including coating applications such as paints, inks, and adhesives, binder applications for nonwoven fabrics, fibers, and paper, plastic structural material applications for automobile parts, housings for electrical appliances, and sports goods, and rubber applications such as vibration-proofing and vibration-damping materials.

The polyester of the present invention can be used in a wide range of applications, including coating applications such as paints, inks, and adhesives, binder applications such as nonwoven fabrics, fibers, and paper, plastic structural material applications such as housings for automobile parts and electrical appliances and sports goods, and rubber applications such as vibration-proofing and vibration-damping materials.

<Curable resin composition>
The curable resin composition of the present invention contains the polymer of the present invention (preferably the polyester of the present invention). In this specification, the curable resin composition is not limited as long as it contains the polymer of the present invention (preferably the polyester of the present invention) and is a curable composition. The curing method is also not particularly limited, and examples of the curable resin composition of the present invention include a thermosetting resin composition that is cured by heat, an energy ray curable resin composition that is cured by energy rays, an oxidative polymerization type curable resin composition that is cured by oxidative polymerization, and a moisture curable resin composition that is cured by chemical reaction with moisture. Among them, a thermosetting resin composition and an oxidative polymerization type curable resin composition are preferred.

In the curable resin composition of the present invention, the content of the polymer of the present invention (preferably the polyester of the present invention) in 100% by mass of the composition is preferably 20 to 99.99% by mass, more preferably 50 to 99.9% by mass. This tends to make it possible to more suitably obtain the effects.
Here, the content of the polymer of the present invention means the total content when a plurality of polymers of the present invention are contained. The same applies to the contents of other components.

In the curable resin composition of the present invention, the total content of alkali metals (preferably the total content of either or both of sodium metal and potassium metal) is preferably 0.02 to 3,496.5 ppm by mass, more preferably 0.1 to 3,496.5 ppm by mass. This tends to make the effect more suitable.

In the following, among the curable resin compositions, a thermosetting resin composition and an oxidative polymerization type curable resin composition will be described in detail, however, the curable resin composition is not limited to a thermosetting resin composition and an oxidative polymerization type curable resin composition.

<<Thermosetting resin composition>>
An example of the thermosetting resin composition of the present invention is a composition containing a base agent containing the polymer (preferably polyester) of the present invention and a curing agent. This composition is generally used for thermosetting cured products, and can be applied to applications such as bake-cured paints, printing inks, and molded products.

The base agent may contain other resins other than the polymer of the present invention (preferably polyester). Examples of other resins include other polyol resins other than the polymer of the present invention. When using these other resins, it is preferable to use 20% by mass or more of the polymer of the present invention (preferably polyester) out of 100% by mass of the resin components contained in the base agent, and more preferably 50% by mass or more.

In the thermosetting resin composition, the content of the main agent in 100% by mass of the composition is preferably 20 to 99.9% by mass, and more preferably 50 to 90% by mass. This tends to make the effect more suitable.

In the thermosetting resin composition, the content of the polymer of the present invention (preferably the polyester of the present invention) in 100% by mass of the composition is preferably 20 to 99.9% by mass, more preferably 50 to 90% by mass. This tends to make the effect more suitable.

The curing agent may contain a component capable of undergoing a curing reaction with the polymer of the present invention (preferably polyester), and examples of such components include amino resins, polyisocyanate resins, resol resins, and epoxy resins. These may be used alone or in combination of two or more. The components of the curing agent are appropriately selected depending on the application and use environment of the curable resin composition, the desired physical properties of the cured product, etc., but as long as the polymer of the present invention (preferably the polyester of the present invention) is used as the main agent, the effects of the present invention will be fully exerted regardless of which curing agent is used. Among them, amino resins are preferred.

Specific examples of the amino resin include methylolated amino resins synthesized from at least one of melamine, urea, and benzoguanamine and formaldehydes; and methylolated amino resins in which some or all of the methylol groups have been alkyl-etherified with lower monohydric alcohols such as methanol, ethanol, propanol, isopropanol, butanol, and isobutanol. These may be used alone or in combination of two or more. Of these, melamine is preferred, and butylated melamine is more preferred.

In the thermosetting resin composition, the content of the curing agent in 100% by mass of the composition is preferably 0.1 to 80% by mass, and more preferably 1 to 50% by mass. This tends to make the effect more suitable.

The thermosetting resin composition may contain a curing catalyst (acid curing catalyst).
Examples of the curing catalyst include acid compounds such as p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, monoalkyl phosphoric acid, dialkyl phosphoric acid, monoalkyl phosphorous acid, dialkyl phosphorous acid, and dodecylbenzenesulfonic acid, and derivatives thereof such as neutralized salts. These may be used alone or in combination of two or more. Among these, dodecylbenzenesulfonic acid is preferred.

In the thermosetting resin composition, the content of the curing catalyst in 100% by mass of the composition is preferably 0.001 to 10% by mass, and more preferably 0.01 to 5% by mass. This tends to make the effect more suitable.

<<Oxidative polymerization type curable resin composition>>
An example of the oxidative polymerization type curable resin composition of the present invention is a composition containing the polymer of the present invention (preferably polyester) and a curing accelerator. This composition is generally used for oxidative polymerization type cured products, and can be applied to applications such as oxidative polymerization paints, printing inks, and molded products.

In the oxidative polymerization type curable resin composition, the content of the polymer of the present invention (preferably polyester) in 100% by mass of the composition is preferably 20 to 99.99% by mass, more preferably 50 to 99.9% by mass. This tends to make the effect more suitable.

Examples of the curing accelerator (dryer) include metal salts (metal soaps) of heavy metals that can have multiple valences, such as cobalt, manganese, and iron, and various carboxylic acids, such as 2-ethylhexanoic acid (octylic acid) and neodecanoic acid. These may be used alone or in combination of two or more. Of these, cobalt salts are preferred, and cobalt 2-ethylhexanoate is more preferred.

In the oxidative polymerization type curable resin composition, the content of the curing accelerator in 100% by mass of the composition is preferably 0.001 to 10% by mass, and more preferably 0.01 to 5% by mass. This tends to make the effect more suitable.

The oxidative polymerization type curable resin composition may contain a curing accelerator (auxiliary drier). Examples of the curing accelerator (auxiliary drier) include metal salts (metal soaps) of at least one metal selected from the group consisting of alkali metals such as potassium and sodium; alkaline earth metals such as calcium and strontium; and heavy metals such as zirconium and lead; and various carboxylic acids such as 2-ethylhexanoic acid (octylic acid) and neodecanoic acid. These may be used alone or in combination of two or more.

In the present invention, the content of the curing accelerator assistant can be reduced without delaying the drying time. In the oxidative polymerization type curable resin composition, the content of the curing accelerator assistant in 100% by mass of the composition is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, particularly preferably 0.5% by mass or less, and most preferably 0.1% by mass or less.

In addition to the above components, the curable resin composition of the present invention may contain pigments, pigment dispersants, matting agents, leveling agents, drying inhibitors, UV absorbers, defoamers, thickeners, anti-settling agents, organic solvents, etc. These may be used alone or in combination of two or more. The blending ratio of each of these components and the type of blend are appropriately adjusted depending on the application and desired performance of the curable resin composition. The curable resin composition of the present invention may be a one-component type or a two-component type. When the curable resin composition of the present invention is a two-component type, the various additives can be added to either the base agent or the curing agent, or both.

<Paint>
The coating material of the present invention contains at least the curable resin composition of the present invention, and may appropriately contain other optional components such as pigments. Among the curable resin compositions of the present invention, the above-mentioned thermosetting resin composition can be used as a baking coating material, and the above-mentioned oxidative polymerization type curable resin composition can be used as an oxidative polymerization type coating material.
The coating material of the present invention can be produced, for example, by mixing the curable resin composition of the present invention and other optional components with various mixers such as a Homodisper.

The coating material of the present invention can be applied to a substrate by conventional methods and then dried and cured to obtain a coating film. Examples of substrates (substrates) to which the coating material of the present invention can be applied include steel, plastic, wood, and concrete. The coating material (coating film) of the present invention can be used in a wide range of applications, including various metals such as home appliances and automobile parts, building materials, plastic parts, precoated metal for metal moldings, can manufacturing, woodwork such as furniture, and concrete materials such as floors and walls.

In this specification, the notation "~" means greater than or equal to the value before "~" and less than or equal to the value after "~". In addition, when multiple numerical ranges are disclosed for a certain characteristic, etc., in this specification using the notation "~", the upper and lower limits of each numerical range can be used in any combination. For example, when two numerical ranges, 0.001 to 500 ppm by mass and 0.05 to 250 ppm by mass, are disclosed for the content of a certain compound, this means that in addition to 0.001 to 500 ppm by mass and 0.05 to 250 ppm by mass, the numerical ranges 0.001 to 250 ppm by mass and 0.05 to 500 ppm by mass are also disclosed.

The present invention will be explained in detail below with reference to examples and comparative examples, but the present invention is not limited to these.

(Example 1: Preparation of 1,6-Hexanediol Composition 1 (1,6-HD Composition 1))
1,6-hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of sodium of 0.02 ppm by mass as determined by ICP-MS analysis, was heated and melted at 80° C., potassium acetate was added so that the potassium content became 500 ppm by mass, and 800 ppm by mass of glycerin was further added. The mixture was then cooled to obtain 1,6-hexanediol composition 1.

(Example 2: Preparation of 1,6-Hexanediol Composition 2 (1,6-HD Composition 2))
1,6-hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of sodium of 0.02 ppm by mass as determined by ICP-MS analysis, was heated and melted at 80° C., sodium acetate was added so that the sodium content became 995 ppm by mass, and 300 ppm by mass of glycerin was further added. The mixture was then cooled to obtain 1,6-hexanediol composition 2.

(Example 3: Preparation of 1,6-Hexanediol Composition 3 (1,6-HD Composition 3))
1,6-hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of sodium of 0.02 ppm by mass as determined by ICP-MS analysis, was heated and melted at 80° C., potassium acetate was added so that the potassium content became 998 ppm by mass, and 1,900 ppm by mass of glycerin was further added. The mixture was then cooled to obtain 1,6-hexanediol composition 3.

(Example 4: Preparation of 1,6-Hexanediol Composition 4 (1,6-HD Composition 4))
1,6-hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of sodium of 0.02 ppm by mass as determined by ICP-MS analysis, was heated and melted at 80° C., potassium acetate was added so that the potassium content became 998 ppm by mass, and 1,900 ppm by mass of 3-methylpentane-1,3,5-triol was further added, and the mixture was cooled to obtain 1,6-hexanediol composition 4.

(Example 5: Preparation of 1,6-Hexanediol Composition 5 (1,6-HD Composition 5))
1,6-Hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of sodium of 0.02 ppm by mass as determined by ICP-MS analysis, was heated and melted at 80° C., potassium acetate was added so that the potassium content was 998 ppm by mass, and 1,900 ppm by mass of pentaerythritol was further added. The mixture was then cooled to obtain 1,6-Hexanediol Composition 5.

(Production Example 1) (Creation of Genetically Modified E. coli)
Plasmid A was prepared by inserting the glycerol dehydratase α, β, and γ subunit genes and the dehydratase reactivator gene derived from Citrobacter freundii between the BamHI and HindIII restriction enzyme cleavage sites of pACYC184 (Nippon Gene Co., Ltd.).
The HpaI gene derived from Escherichia coli was used as the 4,6-dihydroxy-2-oxo-hexanoic acid aldolase, the HpcG gene derived from Escherichia coli was used as the 4,6-dihydroxy-2-oxo-hexanoic acid 4-dehydratase, and the NADPH-dependent oxidoreductase 2-alkenal derived from Arabidopsis thaliana was used as the 6-hydroxy-3,4-dehydro-2-oxohexanoic acid 3-reductase. A plasmid B was prepared by introducing the Lactococcus lactis reductase (GenBank: CAC01710.1) gene as 6-hydroxy-2-oxohexanoic acid 2-reductase, the PanE gene of Lactococcus lactis as 2,6-dihydroxy-hexanoic acid CoA-transferase and the HadA gene derived from Clostridium difficile as 6-hydroxyhexanoyl-CoA-transferase between the BamHI and EcoRI restriction enzyme cleavage sites of the multiple cloning site (MCS) of pUC19 (Nippon Gene Co., Ltd.).
The HadB and HadC genes derived from Clostridium difficile were used as the α and β subunit genes of 2-hydroxyisocaproyl-CoA dehydratase, the HadI gene derived from Clostridium difficile was used as the 2-hydroxyisocaproyl-CoA dehydratase activating enzyme, and the trans-2-enoyl-CoA reductase derived from Treponema denticola was used as the 6-hydroxy-2,3-dehydro-hexanoyl-CoA 2,3-reductase (GenBank: A plasmid C was prepared by introducing the HadB, HadC, and HadI genes into MCS1 and the other genes into MCS2 into pCOLADuet-1 (Novagen) containing the Nocardia iowensis-derived carboxylic acid reductase (GenBank: AAR91681.1) gene as a 6-hydroxyhexanoate 1-reductase, the Nocardia iowensis-derived carboxylic acid reductase (GenBank: AAR91681.1) gene as a 6-hydroxyhexanoate 1-reductase, and the Rhodococcus-derived 6-hydroxyhexanoate dehydrogenase (GenBank: AAN37489.1) gene as a 6-hydroxyhexanal 1-reductase.
In this section, the gene refers to an open reading frame containing a stop codon that codes for each enzyme, and each gene is introduced into a plasmid in such a manner that a sequence containing a T7 promoter and a ribosome binding site is present upstream and a sequence containing a T7 terminator is present downstream. Each gene can be expressed in large amounts in a host strain of Escherichia coli that expresses T7 RNA polymerase by appropriate expression induction.
Plasmids A, B, and C were successively transformed into chemically competent BL21 Star (DE3) cells (Invitrogen) by the heat shock method, and the cells were selected on LB plates containing appropriate antibiotics. As a result, a BL21 Star (DE3) strain containing all of plasmids A, B, and C was obtained.
As a result, 4,6-dihydroxy-2-oxo-hexanoic acid aldolase (2A in the figure of Japanese Patent No. 6680671), 4,6-dihydroxy-2-oxo-hexanoic acid 4-dehydratase (2B in the figure of Japanese Patent No. 6680671), 6-hydroxy-3,4-dehydro-2-oxohexanoic acid 3-reductase (2C in the figure of Japanese Patent No. 6680671), 6-hydroxy-2-oxohexanoic acid 2-reductase (2D in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2E in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2F in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2G in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2H in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2I in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2J in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2K in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2L in the figure of Japanese Patent No. 6680671), 2,6-dihydroxy-hexanoic acid CoA-transferase (2L in the figure of Japanese Patent No. 6680 The inventors have constructed Escherichia coli having genes encoding 10 enzymes in the 1,6-hexanediol pathway, including 6-hydroxy-2,3-dehydro-hexanoyl-CoA 2-dehydratase (2F in the diagram of Japanese Patent No. 6,680,671), 6-hydroxy-2,3-dehydro-hexanoyl-CoA 2,3-reductase (2G in the diagram of Japanese Patent No. 6,680,671), 6-hydroxyhexanoyl-CoA-transferase (4F3 in the diagram of Japanese Patent No. 6,680,671), 6-hydroxyhexanoic acid 1-reductase (5R in the diagram of Japanese Patent No. 6,680,671), and 6-hydroxyhexanal 1-reductase (5S in the diagram of Japanese Patent No. 6,680,671).

(Example 6: Preparation of 1,6-Hexanediol Composition 6 (1,6-HD Composition 6))
The Escherichia coli was inoculated into an autoclave-sterilized medium (carbon source: glucose, glycerin, nitrogen source: enzyme extract, inorganic salts: potassium phosphate, potassium hydroxide, vitamin B12, antibiotics: carbenicillin, kanamycin, chloramphenicol, pH: 7.0, among the above components, glucose and glycerin were raw materials derived from biomass resources), and cultured under aerobic conditions at 30°C for 2 to 3 hours. Thereafter, when the optical density at 600 nm of the Escherichia coli reached 0.3 to 0.6, isopropyl-β-thiogalactopyranoside was added to a final concentration of 0.5 mM and iron (II) sulfate to a final concentration of 10 μM, and the culture was further continued for 3 hours at 30°C to express the enzymes of the 1,6-HD pathway. After the expression, an appropriate amount of carbon source (glucose, glycerin) was added, and the inside of the culture vessel was placed under a nitrogen atmosphere to create anaerobic conditions. Under these conditions, 1,6-hexanediol was produced by culturing at 30° C. for 48 hours. The culture solution was centrifuged at 4° C. for 20 minutes, and the supernatant was collected and filtered using a membrane filter with an appropriate pore size of 0.2 to 0.4 μm to obtain a 1,6-hexanediol composition as the filtrate.

[Purification of 1,6-hexanediol composition]
<Step (a): Ion exchange to remove cations>
Cations contained in the 1,6-hexanediol composition were removed. In step (a), cation exchange was performed in a batch manner. The temperature for contact with the cation exchange resin was set to 40°C, and DIAION SK1BH manufactured by Mitsubishi Chemical Corporation was added as a cation exchange resin to the 1,6-hexanediol composition, followed by stirring for 1 hour. After stirring, filtration was performed to obtain 1,6-hexanediol composition A as the filtrate.
<Step (b): Ion exchange to remove anions>
Anions contained in the 1,6-hexanediol composition A were removed. In the step (b), anion exchange was carried out in a batch manner. The temperature for contact with the anion exchange resin was set to 40° C., and DIAION SA10AOH manufactured by Mitsubishi Chemical Corporation was added as an anion exchange resin to the 1,6-hexanediol composition, followed by stirring for 3 hours. After stirring, filtration was carried out to obtain a 1,6-hexanediol composition B as a filtrate.

<Step (c): Step of Removing Water>
Water contained in the 1,6-hexanediol composition was removed. A thin-film distiller was used as the apparatus for step (c). The jacket temperature was set to 70° C., the 1,6-hexanediol-containing composition was continuously introduced, and water was distilled off from the top. Simultaneously with the distillation of water, the dehydrated 1,6-hexanediol composition C was continuously withdrawn from the bottom as a bottom product. The water concentration in this 1,6-hexanediol composition C was 0.020% by mass (200 ppm by mass).

<Step (d): Distillative separation of low boiling point components>
Components having a boiling point lower than that of 1,6-hexanediol contained in the 1,6-hexanediol composition C were removed in a continuous distillation column. An Oldershaw distillation column was used as the distillation column in the step (d). The 1,6-hexanediol composition C obtained in the step (c) was continuously fed to the distillation column, and the column top temperature was controlled at a constant temperature of 240°C. Continuous distillation was performed from the top of the column, and continuous withdrawal was performed from the bottom of the column to remove the low boiling point components in the 1,6-hexanediol composition C, and a 1,6-hexanediol composition D from which the components having a boiling point lower than that of 1,6-hexanediol had been removed was taken out from the bottom of the column.

<Step (e): Distillative separation of high boiling point components>
Components having a higher boiling point than 1,6-hexanediol contained in 1,6-hexanediol composition D were removed in a continuous distillation column. An Oldershaw distillation column was used as the distillation column in step (e). 1,6-hexanediol composition D obtained in step (d) was continuously fed to the distillation column, and the column bottom temperature was controlled to be constant at 260°C. Continuous extraction was performed from the column bottom to remove the high boiling point components in 1,6-hexanediol composition D. 1,6-hexanediol composition E (1,6-HD composition 6) from which components having a higher boiling point than 1,6-hexanediol were removed was obtained from the column top (column top distillate).

The analytical results of the obtained 1,6-HD composition 6 are shown below. The glycerin content was measured by GC analysis, and the contents of potassium metal element and sodium metal element were measured by ICP-MS analysis.
Glycerin: 800 ppm by mass
Potassium metal element: 3,080 ppm by mass
Sodium metal element: 1,890 ppm by mass
GC analysis details
Apparatus: Agilent GC-MS (GC7890B/MSD5977B)
Column: Agilent J&W GC Column-DB-1
Carrier gas: He
Flow rate: 0.966 mL / min
Linear velocity: 99.5 cm/sec
Injection volume: 1 μL
Split ratio: 50
Column temperature: 75°C (hold: 2 min) - 10°C/min (heating rate, 22.5 min) - 300°C (hold: 5.5 min)
Detector: FID

(Comparative Example 1: Preparation of 1,6-Hexanediol Composition 7 (1,6-HD Composition 7))
1,6-hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of sodium of 0.02 ppm by mass as determined by ICP-MS analysis, was used as 1,6-hexanediol composition 7.

(Comparative Example 2: Preparation of 1,6-Hexanediol Composition 8 (1,6-HD Composition 8))
1,6-hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of 0.02 ppm by mass of sodium by ICP-MS analysis, was heated and melted at 80° C., and 800 ppm by mass of glycerin was added and mixed, and the mixture was cooled to obtain 1,6-hexanediol composition 8.

(Comparative Example 3: Preparation of 1,6-Hexanediol Composition 9 (1,6-HD Composition 9))
1,6-hexanediol manufactured by Ube Industries, Ltd., which had an alkali metal element content of sodium of 0.02 ppm by mass as determined by ICP-MS analysis, was heated and melted at 80°C, sodium acetate was added so that the sodium element content was 3,500 ppm by mass, potassium acetate was further added so that the potassium element content was 3,500 ppm by mass, and 800 ppm by mass of glycerin was further added, and the mixture was cooled to obtain 1,6-hexanediol composition 9.

The analytical results of the 1,6-hexanediol compositions obtained in the above Examples and Comparative Examples are shown in Tables 1 and 2.
In addition, in Tables 1 and 2, the detection limits for potassium metal element and sodium metal element were 0.003 mass ppm, respectively, and the detection limit for trihydric or tetrahydric alcohol was 1 mass ppm. In Tables 1 and 2, the 1,6-hexanediol composition to which potassium acetate was added was marked with an O, and the one to which potassium acetate was not added was marked with a -. The same applies to sodium acetate, glycerin, 3-methylpentane-1,3,5-triol, and pentaerythritol. In the tables, "alcohol" refers to trihydric or tetrahydric alcohol, and in this embodiment, the contents of glycerin, 3-methylpentane-1,3,5-triol, or pentaerythritol are shown.

<Polyester synthesis example>
(Synthesis of polyester resin (A-1))
A flask having a stirring rod, a temperature sensor, and a rectifying tube was charged with 276.9 parts by mass of 1,6-HD composition 1, 67.2 parts by mass of neopentyl glycol, 124.5 parts by mass of trimethylolpropane, 500.4 parts by mass of phthalic anhydride, and 415.4 parts by mass of soybean oil fatty acid, and dry nitrogen was flowed into the flask and heated to 210 to 230 ° C. while stirring, to carry out a dehydration condensation reaction. The reaction was stopped when the acid value reached 8.0 mg KOH / g, and after cooling to 150 ° C., xylene was added dropwise to dilute to a solid content of 60 mass%, to obtain a polyester resin A-1 solution. The weight average molecular weight (Mw) of the obtained polyester resin A-1 was 19,300, the hydroxyl value was 30 mg KOH / g, and the acid value was 8.0 mg KOH / g.
(Synthesis of Polyester Resins A-2 to A-9)
Regarding 1,6-HD compositions 2 to 9, polyester resins A-2 to A-9 were synthesized in the same manner.

The analytical results of the polyesters obtained in the above examples and comparative examples are shown in Tables 3 and 4. The acid value and hydroxyl value of the polyesters were measured in accordance with JIS K 0070-1992.

<Preparation of baking (amino resin curing) paint and evaluation of its physical properties>
A baking paint sample A-1 was prepared by blending 300 parts by mass of the polyester A-1, 75 parts by mass of butylated melamine AMIDIR L-117-60 as an amino resin curing agent, and 0.75 parts by mass of NACURE 5225 (dodecylbenzenesulfonic acid) as a curing catalyst. Baking paint samples A-2 to A-9 were prepared in the same manner, except that the polyester was changed to A-2 to A-9.
For each baking paint sample, the time until gelation at 50°C (pot life) was measured, and the sample was coated on an SPCC steel plate with a bar coater, cured at 150°C for 20 minutes, and the pencil hardness of the coating was measured in accordance with JIS K5600-5-4-1999. The evaluation results are shown in Tables 5 and 6.

As can be seen from Tables 5 and 6, in Comparative Example 3, in which a polyester was used with a 1,6-hexanediol composition having a total alkali metal content of more than 5,000 ppm by mass, the coating did not harden, with a hardness of 6B or less. Also, in Comparative Examples 1 and 2, in which a polyester was used with a 1,6-hexanediol composition having a total alkali metal element content of less than 1 ppm by mass, the pot life could not be sufficiently extended. On the other hand, in the examples in which a polyester was used with a 1,6-hexanediol composition having a total alkali metal element content of 1 to 5,000 ppm by mass, it was found that the pot life could be extended without causing poor curing.

<Creation of oxidative polymerization type (dryer curing) paint and evaluation of its physical properties>
The oxidative polymerization paint sample A-1 was prepared by mixing 300 parts by mass of the polyester A-1 with the parts by mass of cobalt dryer (DICNATE Co-OCTOATE 12%) shown in the table below. The oxidative polymerization paint samples A-2 to A-7 were prepared in the same manner, except that the polyester A-1 was changed to A-2 to A-8.
A potassium drier (DICNATE K-OCTOATE 17%) was added as a hardening accelerator (auxiliary drier) to the oxidative polymerization type paint sample A-7-1 of Comparative Example 1 (Comparative Example 1-2).
The prepared coating compositions were applied to SPCC steel plates using a bar coater, and the drying time (time until the coating became tack-free) and the pencil hardness of the coating film after drying at room temperature for one day were measured in accordance with JIS K5600-5-4-1999. The evaluation results are shown in Tables 7 and 8.

From Tables 7 and 8, it can be seen that in the Examples using polyesters using 1,6-hexanediol compositions with a total content of alkali metal elements of 1 to 5,000 ppm by mass, even without blending a curing accelerator (auxiliary drier), curing could be achieved in a short time (drying time (tack-free) of about 2 hours, pencil hardness after curing of about 3B) similarly to the system (Comparative Example 1-2) using a 1,6-HD composition of a petrochemical product blended with a curing accelerator (auxiliary drier).
On the other hand, in Comparative Examples 1 and 2, in which polyesters were used with a 1,6-hexanediol composition having a total alkali metal element content of less than 1 ppm by mass, the curing (drying) time was longer than in the system (Comparative Example 1-2) in which a 1,6-HD composition, a petrochemical product, containing a curing accelerator (auxiliary drier) was used, and in the Examples in which polyesters were used with a 1,6-hexanediol composition having a total alkali metal content of 1 to 5,000 ppm by mass.

In the examples of this specification, the weight average molecular weight (Mw) of the polyester is a value measured by gel permeation chromatography (GPC) under the following conditions.
Measuring device: HLC-8320GPC manufactured by Tosoh Corporation
Columns: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, and TSKgel 1000HXL manufactured by Tosoh Corporation were used in series connection.
Detector: RI (differential refractometer)
Data processing: Multistation GPC-8020 model II manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40°C
Solvent: Tetrahydrofuran Flow rate: 0.1 ml/min Standard: Monodisperse polystyrene Sample: 0.2% tetrahydrofuran solution (based on resin solids) filtered through a microfilter (100 μl)
Standard sample: A calibration curve was prepared using the following standard polystyrene.
(Standard polystyrene)
"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

Claims (8)

A 1,6-hexanediol composition containing 1,6-hexanediol and an alkali metal element,
the total content of the alkali metal elements relative to the total amount of the composition is in the range of 1 to 5,000 ppm by mass;
A 1,6-hexanediol composition further comprising a trihydric or tetrahydric alcohol, the content of the alcohol being in the range of 0.1 to 2,000 ppm by mass relative to the total amount of the 1,6-hexanediol composition. The 1,6-hexanediol composition according to claim 1, wherein the alcohol is a trihydric aliphatic alcohol. The 1,6-hexanediol composition according to claim 2, wherein the alcohol is glycerin. A method for producing the 1,6-hexanediol composition according to claim 1 or 2 from a biomass resource using a microorganism . A polymer using the 1,6-hexanediol composition according to claim 1 or 2 as a reaction raw material. The polymer of claim 5, wherein the polymer is a polyester. A curable resin composition containing the polymer according to claim 5. A coating material containing the curable resin composition according to claim 7.