Propylene glycol monomethyl ether acetate composition

Abstract

A propylene glycol monomethyl ether acetate composition containing propylene glycol 1-monomethyl ether 2-acetate, acetic acid, propionic acid, and water, wherein the propionic acid content is 2-30 ppm with respect to 100 mass% of the propylene glycol monomethyl ether acetate composition, the total content of the acetic acid and the propionic acid is 5-80 ppm with respect to 100 mass% of the propylene glycol monomethyl ether acetate composition, and the water content is 17-250 ppm with respect to 100 mass% of the propylene glycol monomethyl ether acetate composition.

Description

Propylene glycol monomethyl ether acetate composition

[0001] The present invention relates to propylene glycol monomethyl ether acetate compositions.

[0002] Propylene glycol monomethyl ether acetate (hereinafter also referred to as "PMA") is known as an organic solvent used in various applications. PMA is produced, for example, by a direct esterification reaction of propylene glycol monomethyl ether (hereinafter also referred to as "PM") with acetic acid under specific conditions (see, for example, Patent Document 1).

[0003] Chinese Patent Application Publication No. 1515537

[0004] When PMA obtained by the method described in Patent Document 1 was stored for a long period of time and its composition was confirmed, it was found that the purity of the PMA tended to decrease.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a propylene glycol monomethyl ether acetate composition having excellent storage stability.

[0006] The present inventors have found that a propylene glycol monomethyl ether acetate composition containing specific components can solve the above problems, and have completed the present invention.

[0007] That is, the present invention encompasses the following aspects: [1] A propylene glycol monomethyl ether acetate composition comprising propylene glycol 1-monomethyl ether 2-acetate, acetic acid, propionic acid, and water, wherein the propionic acid content is 2 ppm or more and 30 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition, the sum of the acetic acid and propionic acid contents is 5 ppm or more and 80 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition, and the water content is 17 ppm or more and 250 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition. [2] The propylene glycol monomethyl ether acetate composition according to [1], wherein the content of propylene glycol monomethyl ether is 4.0 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition. [3] The propylene glycol monomethyl ether acetate composition according to [1] or [2], wherein the content of water is 20 ppm or more and 100 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition. [4] The propylene glycol monomethyl ether acetate composition according to any one of [1] to [3], wherein, when the propylene glycol monomethyl ether acetate composition is subjected to the following test and then subjected to gas chromatography analysis under the following conditions, when the relative retention time of the peak of propylene glycol 1-monomethyl ether 2-acetate is set to 1.00, the area ratio of the peak appearing in the relative retention time range of 0.64 to 0.72 is 800 ppm or less. (Test) The propylene glycol monomethyl ether acetate composition is heated to 80° C. in a borosilicate glass vessel under a nitrogen atmosphere and maintained for 5 days.(Gas chromatography analysis conditions) Analytical column: a column with a stationary phase of polyethylene glycol, length 30 m × inner diameter 0.25 mm × film thickness 0.25 μm Heating conditions: held at 50°C for 10 minutes, then heated to 250°C at 5°C / min Sample introduction temperature: 250°C Carrier gas: nitrogen Column gas flow rate: 1.0 mL / min Detector and detection temperature: hydrogen flame ionization detector, 250°C Control mode: column flow rate Split ratio: 50:1 Injection volume: 2.0 μL

[0008] According to the present invention, a propylene glycol monomethyl ether acetate composition having excellent storage stability can be provided.

[0009] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0010] <Propylene glycol monomethyl ether acetate composition> The propylene glycol monomethyl ether acetate composition (hereinafter also referred to as "PMA composition") of the present embodiment is a propylene glycol monomethyl ether acetate composition containing propylene glycol 1-monomethyl ether 2-acetate (hereinafter also referred to as "PGMEA"), acetic acid, propionic acid, and water, wherein the content of the propionic acid is 2 ppm or more and 30 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition, the sum of the contents of the acetic acid and the propionic acid is 5 ppm or more and 80 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition, and the content of the water is 17 ppm or more and 250 ppm or less, based on 100% by mass of the propylene glycol monomethyl ether acetate composition. The PMA composition of the present embodiment has such a structure and therefore has excellent storage stability.

[0011] The reason why the PMA composition of this embodiment has excellent storage stability is not entirely clear, and while it is not intended to limit the reason, it is speculated as follows. During long-term storage of a propylene glycol monomethyl ether acetate composition, decomposition of PGMEA and the generation of impurities are thought to be one of the factors affecting storage stability. Examples of causes of decomposition of carboxylic acid esters such as PGMEA include hydrolysis. Generally, in the presence of acid and water, carboxylic acid esters hydrolyze to form carboxylic acids and alcohols. It is also believed that carboxylic acid esters tend to hydrolyze more when the acid content is high. However, in the PMA composition of this embodiment, by having the propionic acid content, the sum of the acetic acid content and the propionic acid content, and the water content within the above ranges, transesterification between alcohols that may be generated by hydrolysis of PGMEA and the acetyl groups of PGMEA is suppressed, which is thought to result in suppression of hydrolysis of PGMEA, contrary to the aforementioned tendency. However, the above is merely one possible reason why the PMA composition of this embodiment has excellent storage stability, and the mechanism of action of this embodiment is not limited to this.

[0012] The PMA composition of this embodiment can be used for industrial purposes, including, but not limited to, inks, thinners, pharmaceuticals and agricultural chemicals, plasticizers, surfactants, polymeric materials, lubricants, adhesives, detergents, electronic materials, and paints. Electronic materials include, but are not limited to, liquid crystal displays (LCDs) and semiconductor devices. Because of its excellent storage stability, the PMA composition of this embodiment is preferably used in the manufacture of semiconductor devices. Specific examples of applications related to the manufacture of semiconductor devices include, but are not limited to, cleaning solutions (e.g., treatment solutions for cleaning substrate surfaces after resist stripping), prewet solutions (e.g., treatment solutions used before resist coating to reduce resist solvent consumption), resist solvents (e.g., treatment solutions for dissolving photosensitizers and resins), developers (e.g., treatment solutions for removing soluble resins after exposure of negative resists), and strippers (e.g., treatment solutions used to remove hardened resists after etching). From the viewpoint of preventing product defects in the manufacture of semiconductor devices, the PMA composition of the present embodiment is preferably used as a resist solvent, a pre-wet liquid, a solvent for an edge rinse (rinse for removing resist from the outer periphery of a wafer) and a back rinse (rinse for removing resist from the back surface of a wafer) used during resist coating, a developer used during negative resist development, a rinse liquid used during rinsing of a negative resist after development, a cleaning liquid or rinse liquid used for removing resist after etching, and the like.

[0013] (Propylene glycol 1-monomethyl ether 2-acetate) The propylene glycol 1-monomethyl ether 2-acetate in the PMA composition of the present embodiment can be identified and quantified, for example, by the following gas chromatography (hereinafter also referred to as "GC") analysis. (Gas Chromatography Analysis) Analytical column: a column having a polyethylene glycol stationary phase and a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 0.25 μm Heating conditions: maintained at 50° C. for 10 minutes, and then heated to 250° C. at 5° C. / min Sample introduction temperature: 250° C. Carrier gas: nitrogen Column gas flow rate: 1.0 mL / min Detector and detection temperature: flame ionization detector, 250° C. Control mode: column flow rate Split ratio: 50:1 Injection amount: 2.0 μL The content of PGMEA in the PMA composition of this embodiment can be appropriately determined depending on the application of the PMA composition of this embodiment, and is not particularly limited. However, from the viewpoint of use in applications requiring high purity, the peak area ratio to the total peak area in the chart obtained as a result of GC analysis is preferably 99.94% or more, more preferably 99.95% or more, and even more preferably 99.96% or more. In this embodiment, the "total peak area" refers to the sum of the areas of all peaks appearing in the chart obtained as a result of GC analysis. In this embodiment, "all peaks" can be specified as meaning all peaks that appear when the analysis is continued and stopped from a relative retention time of 0.14 to 2.95, assuming that the relative retention time of the PGMEA peak is 1.00.

[0014] (Acetic Acid) The PMA composition of this embodiment contains acetic acid. From the viewpoint of storage stability, the content of acetic acid in the PMA composition of this embodiment is preferably 3 ppm to 78 ppm, more preferably 5 ppm to 72 ppm, and even more preferably 7 ppm to 69 ppm, based on 100% by mass of the PMA composition of this embodiment. The content can be measured based on the method described in the Examples below. The content can be adjusted to the above-mentioned range, for example, by appropriately adding acetic acid after performing the adsorption treatment described below. The content can also be adjusted to the above-mentioned range, for example, by appropriately changing the conditions of the adsorption treatment and dehydration treatment (e.g., treatment time, etc.).

[0015] (Propionic Acid) The PMA composition of this embodiment contains propionic acid. From the viewpoint of storage stability, the propionic acid content in the PMA composition of this embodiment is 2 ppm to 30 ppm, preferably 3 ppm to 25 ppm, and more preferably 3 ppm to 20 ppm, relative to 100% by mass of the PMA composition of this embodiment. The content can be measured based on the method described in the Examples below. The content can be adjusted to the above-mentioned range, for example, by appropriately adding propionic acid after performing the adsorption treatment described below. The content can also be adjusted to the above-mentioned range, for example, by appropriately changing the conditions of the adsorption treatment and dehydration treatment (e.g., treatment time, etc.).

[0016] (Sum of Acetic Acid and Propionic Acid Contents) In this embodiment, from the viewpoint of storage stability, the sum of the contents of acetic acid and propionic acid in the PMA composition of this embodiment is 5 ppm to 80 ppm, preferably 8 ppm to 75 ppm, and more preferably 10 ppm to 72 ppm, based on 100% by mass of the PMA composition of this embodiment. The above contents can be measured based on the method described in the Examples below. The above contents can be adjusted to the above ranges, for example, by appropriately adding acetic acid and / or propionic acid after performing the adsorption treatment described below. The above contents can also be adjusted to the above ranges, for example, by appropriately changing the conditions of the adsorption treatment and dehydration treatment (e.g., treatment time, etc.).

[0017] (Water) The PMA composition of this embodiment contains water. From the viewpoint of storage stability, the water content in the PMA composition of this embodiment is 17 ppm to 250 ppm, preferably 18 ppm to 200 ppm, and more preferably 20 ppm to 100 ppm, based on 100% by mass of the PMA composition of this embodiment. The water content can be measured based on the method described in the Examples below. The water content can be adjusted to the above-mentioned range, for example, by adding water appropriately after performing the dehydration treatment described below. The water content can also be adjusted to the above-mentioned range, for example, by appropriately changing the dehydration treatment conditions (e.g., treatment time, etc.).

[0018] (PM) The PMA composition of this embodiment may contain propylene glycol monomethyl ether (PM). PM tends to undergo intramolecular dehydration reactions in the presence of acid, which can affect the storage stability of the PMA composition. Therefore, a low PM content is preferable. That is, from the viewpoint of storage stability, the PM content in the PMA composition of this embodiment is preferably 4.0 ppm or less, based on 100% by mass of the PMA composition of this embodiment, and more preferably below the detection limit (2 ppm or less by GC analysis). The PM content can be measured based on the method described in the Examples below. The PM content can be adjusted to the above-mentioned range, for example, by azeotropic dehydration after esterification, subsequent distillative purification, adsorption treatment, or the like. In particular, in the adsorption treatment (step (c) described below), the PM content can be controlled by appropriately selecting an adsorbent, for example. In this embodiment, various ion exchange resins can be used as the adsorbent, such as Kyoward 500 (registered trademark) manufactured by Kyowa Chemical Industry Co., Ltd. and ORLITE DS-6 manufactured by Organo Corporation. However, since the use of a weakly basic ion exchange resin tends to be more effective in reducing the amount of PM than the use of a general inorganic synthetic adsorbent, it is preferable to carry out the adsorption treatment using a weakly basic ion exchange resin such as ORLITE DS-6 manufactured by Organo Corporation.

[0019] (Component A) From the viewpoint of storage stability, when the PMA composition of this embodiment is subjected to the following test and then subjected to the above-mentioned GC analysis, the area ratio of a peak appearing in the relative retention time range of 0.64 to 0.72 (the substance corresponding to this peak is also referred to as "Component A"), where the relative retention time of the peak of propylene glycol 1-monomethyl ether 2-acetate is taken as 1.00, is preferably 800 ppm or less, more preferably 700 ppm or less, and even more preferably 600 ppm or less. (Test) The propylene glycol monomethyl ether acetate composition is heated to 80°C in a nitrogen atmosphere in a borosilicate glass container and maintained for 5 days. The area ratio can be measured based on the method described in the Examples below. The area ratio can be adjusted to the above-mentioned range, for example, by performing the adsorption treatment and / or dehydration treatment described below and then appropriately adding acetic acid, propionic acid, and / or water. The area ratio can also be adjusted to fall within the above range by, for example, appropriately changing the conditions (for example, the treatment time) of the adsorption treatment and / or dehydration treatment.

[0020] (Ethyl Acetate) From the viewpoint of storage stability, when the PMA composition of this embodiment is subjected to the above-described test and then subjected to the above-described GC analysis, the area ratio of the ethyl acetate peak is preferably 120 ppm or less, more preferably 100 ppm or less, and even more preferably 70 ppm or less. The area ratio can be measured based on the method described in the Examples below. The area ratio can be adjusted to the above-described range, for example, by appropriately adding acetic acid, propionic acid, and / or water after performing the below-described adsorption treatment and / or dehydration treatment. The area ratio can also be adjusted to the above-described range, for example, by appropriately changing the conditions of the adsorption treatment and / or dehydration treatment (e.g., treatment time, etc.).

[0021] (Component B) From the viewpoint of storage stability, when the PMA composition of the present embodiment is subjected to the above-described test and then subjected to the above-described GC analysis, the area ratio of a peak appearing in the relative retention time range of 0.37 to 0.44 (the substance corresponding to this peak is also referred to as "Component B"), where the relative retention time of the peak of propylene glycol 1-monomethyl ether 2-acetate is taken as 1.00, is preferably 70 ppm or less, more preferably 65 ppm or less, and even more preferably 60 ppm or less. The area ratio can be measured based on the method described in the Examples below. The area ratio can be adjusted to the above-described range, for example, by appropriately adding acetic acid, propionic acid, and / or water after performing the adsorption treatment and / or dehydration treatment described below. The area ratio can also be adjusted to the above-described range, for example, by appropriately changing the conditions of the adsorption treatment and / or dehydration treatment (e.g., treatment time, etc.).

[0022] (2-Acetoxy-1-propanol) From the viewpoint of storage stability, when the PMA composition of this embodiment is subjected to the above-described test and then subjected to the above-described GC analysis, the area ratio of the 2-acetoxy-1-propanol peak is preferably 240 ppm or less, more preferably 200 ppm or less, and even more preferably 150 ppm or less. The area ratio can be measured based on the method described in the Examples below. The area ratio can be adjusted to the above-described range, for example, by performing the adsorption treatment and / or dehydration treatment described below, followed by appropriately adding acetic acid, propionic acid, and / or water. The area ratio can also be adjusted to the above-described range, for example, by appropriately changing the conditions of the adsorption treatment and / or dehydration treatment (e.g., treatment time, etc.).

[0023] From the viewpoint of storage stability, when the PMA composition of this embodiment is subjected to the above-described test and then subjected to the above-described GC analysis, the area ratio of the PGMEA peak is preferably 99.80% or more, more preferably 99.82% or more, and even more preferably 99.85% or more of the total peak area. The area ratio can be measured according to the method described in the Examples below. The area ratio can be adjusted to the above-described range, for example, by appropriately adding acetic acid, propionic acid, and / or water after performing the adsorption treatment and / or dehydration treatment described below. The area ratio can also be adjusted to the above-described range by, for example, appropriately changing the conditions of the adsorption treatment and / or dehydration treatment (e.g., treatment time, etc.).

[0024] <Method for Producing PMA Composition> The method for producing the PMA composition of this embodiment is not particularly limited, but the following method (hereinafter also referred to as "Method A") is preferred. Method A preferably includes the following steps: (a) obtaining a first product containing PGMEA; (b) distilling the first product to obtain a second product; (c) subjecting the organic acid contained in the second product to an adsorption treatment to obtain a third product; (d) desalting the third product to obtain a fourth product; and (e) dehydrating the fourth product to obtain a PMA composition. The amounts of acetic acid, propionic acid, and water in the PMA composition can be adjusted by steps (c) and (e), but the method may further include a step (f) of adding acetic acid, propionic acid, and / or water to the product obtained via step (e) to obtain a PMA composition.

[0025] (Step (a)) In step (a), a first product containing PGMEA is obtained. Step (a) may include an operation for producing PGMEA based on a conventionally known method. The method for producing PGMEA is not particularly limited, but examples thereof include the method described in Chinese Patent Application Publication No. 1515537. Specifically, PGMEA can be produced by carrying out a direct esterification reaction between PM and acetic acid. The first product may contain raw materials, catalysts, by-products, etc. that can be used in the reaction for producing PGMEA.

[0026] (Step (b)) In step (b), the first product is distilled to obtain a second product. The specific distillation procedure is not particularly limited, and examples thereof include atmospheric distillation and reduced pressure distillation, and such distillation may be performed repeatedly. In this step, raw materials, catalysts, by-products, etc. that may be contained in the first product and that can be used in the reaction to produce PGMEA can be removed. The distillation conditions are not particularly limited, and the distillation can be performed with reference to the conditions described in Chinese Patent Application Publication No. 1515537, for example. The amounts of PM, acetic acid, propionic acid, and water that may be contained in the second product may be greater than 4 ppm, greater than 78 ppm, greater than 30 ppm, and greater than 250 ppm, respectively, based on 100% by mass of the second product.

[0027] (Step (c)) In step (c), the second product is subjected to an adsorption treatment to obtain a third product. The conditions for the adsorption treatment are preferably conditions that can reduce the amounts of acetic acid and propionic acid contained in the second product, and are not particularly limited. For example, the second product may be subjected to an adsorption treatment using ORLITE DS-6 manufactured by Organo Corporation. In this case, the amounts of PM, acetic acid, and propionic acid that may be contained in the third product can be adjusted by adjusting, for example, the amount of ORLITE DS-6 used and the treatment time. The adsorbent such as ORLITE DS-6 used in the adsorption treatment can be removed by filtration using a PTFE (polytetrafluoroethylene) membrane filter or the like.

[0028] (Step (d)) In step (d), the third product is desalted to obtain a fourth product. Specific procedures for the desalting treatment are not particularly limited, and examples include flash distillation or water washing, and such treatments may be repeated. In this step, various amine salts and inorganic salts that may be contained in the third product can be removed. The conditions for flash distillation are not particularly limited, and the distillation can be carried out, for example, by supplying the third product at a linear velocity (LV) of 55 to 65 m / Hr to a flash drum heated to about 65 to 75°C under a reduced pressure (absolute pressure in the system during distillation; the same applies hereinafter) of 2.5 to 3.5 kPa.

[0029] (Step (e)) In step (e), the fourth product is subjected to a dehydration treatment to obtain a PMA composition. The conditions for the dehydration treatment are preferably conditions that can reduce the amount of water contained in the fourth product, and are not particularly limited, but examples include dehydration treatment by nitrogen bubbling. In this case, the amount of water contained in the PMA composition can be adjusted, for example, by adjusting the treatment time, etc.

[0030] (Step (f)) In step (f), acetic acid, propionic acid, and / or water can be added to the product obtained through step (e) to adjust the amount of acetic acid, propionic acid, and / or water in the PMA composition. The amount of acetic acid, propionic acid, and / or water to be added is not particularly limited, but can be determined, for example, based on the difference between the acetic acid content C1, propionic acid content C2, and water content C3 in the desired PMA composition and the acetic acid content C1', propionic acid content C2', and water content C3' in the product obtained through step (e). Each content can be measured based on the method described in the Examples below.

[0031] The present embodiment will be described in more detail below based on examples, but the present embodiment is not limited to these examples.

[0032] [Example 1] (Step (a)) A first product containing PGMEA was synthesized by referring to the method described in Chinese Patent Application Publication No. 1515537. That is, the first product containing PGMEA was obtained by direct esterification of PM with acetic acid.

[0033] (Step (b)) Next, the first product containing PGMEA was introduced into a distillation column and subjected to atmospheric distillation. That is, the reflux ratio was set to 1 to 9, and unreacted raw materials and the like were first distilled off, and then a fraction containing PGMEA was recovered.

[0034] Next, the fraction containing PGMEA obtained by atmospheric distillation was introduced into a distillation column and subjected to reduced pressure distillation. That is, the degree of vacuum in the distillation column was set to 21.3 kPa, the temperature in the distillation column was controlled to be 110°C or less, the reflux ratio was set to 1 to 6, and the fraction at the top of the column (temperature 98 to 100°C) was recovered as the second product. The amounts of PM, acetic acid, propionic acid, and water contained in the obtained second product were below the detection limit (below the detection limit in GC analysis), 90 ppm, 50 ppm, and 300 ppm, respectively, based on 100% mass of the second product.

[0035] The contents of PM, acetic acid, propionic acid, and water in the second product, and the contents of PGMEA, PM, acetic acid, propionic acid, and water in the PMA composition of Example 1 described below were confirmed by the following methods. That is, the water content was measured with a Karl Fischer moisture meter (product name "AQ-2200A", manufactured by Hiranuma Corporation, Karl Fischer coulometric titration method). The contents of PGMEA, PM, acetic acid, and propionic acid were measured by GC analysis under the following conditions. (Gas Chromatography Analysis) Analytical apparatus: Nexis GC-2030 manufactured by Shimadzu Corporation Analytical column: DB-WAX manufactured by Agilent Technologies (a column having a stationary phase of polyethylene glycol, a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 0.25 μm) Heating conditions: After holding at 50° C. for 10 minutes, the temperature was increased to 250° C. at 5° C. / min Sample introduction temperature: 250° C. Carrier gas: nitrogen Column gas flow rate: 1.0 mL / min Detector and detection temperature: hydrogen flame ionization detector, 250° C. Control mode: column flow rate Split ratio: 50:1 Injection amount: 2.0 μL In the above GC analysis, the content of PGMEA was calculated as the area percentage of the PGMEA peak relative to the total peak area of ​​the chart obtained as a result of GC analysis. The PM content was calculated as the percentage of the PM peak area relative to the total peak area in the chart obtained as a result of GC analysis. The contents of acetic acid and propionic acid were calculated by the absolute calibration curve method using GC analysis.

[0036] (Step (c)) To the second product (100% by volume) obtained above, 5.0% by volume of ORLITE DS-6 manufactured by Organo Corporation was added and stirred for 30 minutes to adsorb and remove acetic acid and propionic acid. This was filtered through a PTFE membrane filter (model: T020A047A, pore size: 0.20 μm) manufactured by ADVANTEC to obtain a third product.

[0037] (Step (d)) Next, the third product was introduced into a distillation column and subjected to flash distillation. That is, the third product was supplied to a flash drum heated to about 70°C under a reduced pressure of 3 kPa at a linear velocity (LV) of 59 m / Hr, and 90 mass% (relative to 100 mass% of the third product) was distilled from the top of the flash drum, resulting in a product called a fourth product.

[0038] (Step (e)) Nitrogen passed through a Kinoshita Ball Filter (model number: 501G-1, filter diameter: 10 mm, filter pores: 100-120 μm) manufactured by Kinoshita Rika Kogyo Co., Ltd. was bubbled through the fourth product at 3-5 L / min for 110 minutes for dehydration, yielding the PMA composition of Example 1. The resulting PMA composition was subjected to GC analysis and moisture analysis under the same conditions as above. The amounts of PGMEA, PM, acetic acid, propionic acid, and water contained in the PMA composition were 99.966 area %, below the detection limit, 10 ppm, 5 ppm, and 20 ppm, respectively, based on 100% by mass of the PMA composition. Details of the analysis results are shown in Table 1. In the following examples and comparative examples, the amounts of PGMEA, PM, acetic acid, propionic acid, and water in the PMA composition were confirmed in the same manner as above.

[0039] The PMA composition was then subjected to the following test. That is, the PMA composition was placed in a 110 mL borosilicate glass container, nitrogen was sealed inside, and the container was heated in an incubator (product name "ST-110B1", manufactured by ESPEC) and maintained at 80°C for 5 days. After the test, the PMA composition was subjected to GC analysis under the conditions described above.

[0040] GC Chart A obtained by GC analysis before the test was compared with GC Chart B obtained by GC analysis after the test. Substances that had a peak area ratio of less than 5 ppm in Chart A but had a peak area ratio of 5 ppm or more in Chart B were deemed to have a significant effect on the storage stability of the PMA composition, and their amounts were evaluated. That is, when the relative retention time of the peak of propylene glycol 1-monomethyl ether 2-acetate in GC Chart B was set to 1.00, the area ratios of the peak appearing at relative retention times of 0.64 to 0.72 and the peak appearing at relative retention times of 0.37 to 0.44 were 567.6 area ppm and 53.1 area ppm, respectively. Furthermore, the area ratios of the peaks of ethyl acetate and 2-acetoxy-1-propanol in GC Chart B were 51.7 area ppm and 126.8 area ppm, respectively. In GC chart A, the peak in the range of relative retention time 0.62 to 0.64 corresponding to propylene glycol monomethyl ether (PM) was below the detection limit (2 ppm or less). Details of the analysis results are shown in Table 1.

[0041] Example 2 The PMA composition of Example 2 was obtained in the same manner as in Example 1, except that 4.0% by volume of ORLITE DS-6 manufactured by Organo Corporation was added to the second product (100% by volume) in step (c) in Example 1, and nitrogen was bubbled through the fourth product in step (e) at the aforementioned supply rate for 105 minutes. This PMA composition was subjected to the same tests as in Example 1 and then to the same gas chromatography analysis as in Example 1. Details of the analysis results are shown in Table 1.

[0042] Example 3 The PMA composition of Example 3 was obtained in the same manner as in Example 1, except that 5.1% by volume of ORLITE DS-6 manufactured by Organo Corporation was added to the second product (100% by volume) in step (c) in Example 1, and nitrogen was bubbled through the fourth product in step (e) at the aforementioned supply rate for 90 minutes. This PMA composition was subjected to the same tests as in Example 1 and then to the same gas chromatography analysis as in Example 1. Details of the analysis results are shown in Table 1.

[0043] Example 4 The PMA composition of Example 4 was obtained in the same manner as in Example 1, except that 3.4% by volume of ORLITE DS-6 manufactured by Organo Corporation was added to the second product (100% by volume) in step (c) in Example 1, and nitrogen was bubbled through the fourth product in step (e) at the aforementioned supply rate for 80 minutes. This PMA composition was subjected to the same tests as in Example 1 and then to the same gas chromatography analysis as in Example 1. Details of the analysis results are shown in Table 1.

[0044] Example 5 The PMA composition of Example 5 was obtained in the same manner as in Example 1, except that 2.5% by volume of ORLITE DS-6 manufactured by Organo Corporation was added to the second product (100% by volume) in step (c) in Example 1, and nitrogen was bubbled through the fourth product in step (e) at the aforementioned supply rate for 80 minutes. This PMA composition was subjected to the same tests as in Example 1 and then to the same gas chromatography analysis as in Example 1. Details of the analysis results are shown in Table 1.

[0045] Comparative Example 1 A PMA composition of Comparative Example 1 was obtained in the same manner as in Example 1, except that 5.0% by volume of ORLITE DS-6 manufactured by Organo Corporation was added to the second product (100% by volume) in step (c) in Example 1, and that nitrogen was bubbled through the fourth product in step (e) at the aforementioned supply rate for 115 minutes. This PMA composition was subjected to the same tests as in Example 1 and then to the same gas chromatography analysis as in Example 1. Details of the analysis results are shown in Table 1.

[0046]

Claims

1. A propylene glycol monomethyl ether acetate composition comprising propylene glycol 1 - monomethyl ether 2 - acetate, acetic acid, propionic acid, and water, wherein the content of the propionic acid is 2 ppm or more and 30 ppm or less with respect to 100% by mass of the propylene glycol monomethyl ether acetate composition, the sum of the contents of the acetic acid and the propionic acid is 5 ppm or more and 80 ppm or less with respect to 100% by mass of the propylene glycol monomethyl ether acetate composition, and the content of the water is 17 ppm or more and 250 ppm or less with respect to 100% by mass of the propylene glycol monomethyl ether acetate composition.

2. The propylene glycol monomethyl ether acetate composition according to claim 1, wherein the content of propylene glycol monomethyl ether is 4.0 ppm or less with respect to 100% by mass of the propylene glycol monomethyl ether acetate composition.

3. The propylene glycol monomethyl ether acetate composition according to claim 1 or 2, wherein the content of the water is 20 ppm or more and 100 ppm or less with respect to 100% by mass of the propylene glycol monomethyl ether acetate composition.

4. When the propylene glycol monomethyl ether acetate composition is subjected to the following test and then subjected to gas chromatographic analysis under the following conditions, when the relative retention time of the peak of propylene glycol 1-monomethyl ether 2-acetate is taken as 1.00, the area ratio of the peak appearing in the range of relative retention time of 0.64 to 0.72 is 800 ppm or less. The propylene glycol monomethyl ether acetate composition according to claim 1 or 2. (Test) The propylene glycol monomethyl ether acetate composition is heated to 80° C. in a container made of borosilicate glass under a nitrogen atmosphere and held for 5 days. (Conditions for gas chromatographic analysis) Analysis column: A column with a polyethylene glycol stationary phase, a length of 30 m × an inner diameter of 0.25 mm × a film thickness of 0.25 μm Temperature rising condition: Hold at 50° C. for 10 minutes, then raise the temperature to 250° C. at 5° C. / min Sample introduction temperature: 250° C. Carrier gas: Nitrogen Gas flow rate of the column: 1.0 mL / min Detector and detection temperature: Flame ionization detector, 250° C. Control mode: Column flow Split ratio: 50:1 Injection volume: 2.0 μL

Images