Acetalized product of ethylene vinyl alcohol copolymer, resin composition containing said acetalized product, resin sheet, interlayer film for laminated glass, and laminated glass

Abstract

The present invention relates to an acetalized product of an ethylene vinyl alcohol copolymer, the acetalized product containing 0.1-80 mol% of ethylene units, 0.1-94.9 mol% of vinyl alcohol units, and 5-50 mol% of acetal units with respect to all monomer units constituting the acetalized product. The acetalized product has a half-value width W0.5h of 1.10-1.35 as determined by reversed phase distribution gradient high performance liquid chromatography analysis based on a water-ethanol eluent in accordance with JIS K 0124 (2011).

Description

Acetalized ethylene vinyl alcohol copolymer and resin compositions containing the acetalized ethylene vinyl alcohol copolymer, resin sheets, interlayers for laminated glass, and laminated glass. 【0001】 This patent application claims priority under the Paris Convention with respect to Japanese Patent Application No. 2024-214306 (filing date: December 9, 2024), which is incorporated herein by reference in its entirety. The present invention relates to acetalized ethylene vinyl alcohol copolymers, compositions containing said acetalized compounds, resin sheets comprising said compositions, interlayers for laminated glass comprising said resin sheets, and laminated glass having said interlayers. 【0002】 Laminated glass is a composite glass in which an interlayer for laminated glass containing a thermoplastic resin such as polyurethane, ethylene-vinyl acetate copolymer, or polyvinyl acetal resin is interposed between multiple sheets of glass. 【0003】 Laminated glass is safer because even if it breaks due to an external impact, the glass fragments are less likely to scatter. Therefore, it is widely used as windshields, side windows, and rear windows in vehicles such as automobiles, as well as windows in aircraft and buildings. 【0004】 Patent Document 1 describes an acetalized ethylene vinyl alcohol copolymer in which the symmetry coefficient representing the degree of acetalization distribution and the melting peak temperature / midpoint glass transition temperature ratio representing the degree of crystallinity are each adjusted to a specific range. The acetalized product of Patent Document 1 and compositions containing the acetalized product are said to be able to form a resin sheet that maintains transparency and puncture resistance while exhibiting excellent self-supporting and creep resistance in high-temperature environments. 【0005】Patent Document 2 describes a modified vinyl acetal resin for laminated glass interlayers, which contains 25 to 60 mol% ethylene units and 24 to 71 mol% vinyl alcohol units, and has a degree of acetalization defined as the proportion of acetalized vinyl alcohol units among structural units other than ethylene units (5 mol% to less than 40 mol%). The modified vinyl acetal resin of Patent Document 2 is said to have a good balance of transparency, impact strength, heat resistance, and moldability required for laminated glass interlayers. 【0006】 International Publication No. 2022 / 220085, International Publication No. 2020 / 196186 【0007】 In recent years, the performance requirements for laminated glass have increased, and the interlayers that make up laminated glass are now required to have excellent transparency, excellent heat resistance, and excellent penetration resistance. In particular, regarding transparency, in addition to low haze, excellent hue is required. Furthermore, regarding heat resistance in particular, higher heat resistance is required, such as high self-support even in high-temperature environments, and high creep resistance, allowing high strength to be maintained even after a long period of time. 【0008】 Patent Document 1 does not describe the hue. According to the inventors' research, it was found that there is room for improvement regarding the hue of the resin sheet containing the acetalized product described in Patent Document 1. 【0009】 According to our investigations, the modified vinyl acetal resin described in Patent Document 2 may not have sufficient self-supporting properties and creep resistance under high-temperature environments, and there is room for improvement. 【0010】 The present invention solves the aforementioned problems and aims to provide an acetalized ethylene vinyl alcohol copolymer and a resin composition containing said acetalized copolymer that can form a resin sheet with excellent hue, self-supporting properties and creep resistance in high-temperature environments. 【0011】 The present invention provides the following embodiments. 【0012】 [Aspect 1] An acetalized ethylene vinyl alcohol copolymer comprising, based on the total monomer units constituting the acetalized, 0.1 to 80 mol%, preferably 20 to 60 mol%, more preferably 25 to 55 mol%, even more preferably 30 to 50 mol%, most preferably 34 to 44 mol% of ethylene units, 0.1 to 94.9 mol%, preferably 30 to 80 mol%, more preferably 35 to 75 mol%, even more preferably 40 to 70 mol%, particularly preferably 40 to 65 mol% of vinyl alcohol units, and 5 to 50 mol%, preferably 10 to 45 mol%, more preferably 15 to 35 mol%, even more preferably 18 to 30 mol%, particularly preferably 18 to 25 mol% of acetal units, wherein the full width at half maximum (FWHM) W is determined by reverse-phase partition gradient high-performance liquid chromatography analysis using a water-ethanol eluent in accordance with JIS K0124:2011. ０．５ｈ However, the acetal compound has a concentration of 1.10 to 1.35, preferably 1.15 to 1.32, and more preferably 1.20 to 1.30. 【0013】 [Aspect 2] The acetalized product according to [Aspect 1], wherein the melting peak temperature measured in accordance with JIS K7121:2012 is 105°C or higher, for example, 105 to 180°C, preferably 120 to 170°C, more preferably 130 to 160°C, and even more preferably 135 to 157°C. 【0014】 [Aspect 3] The acetal compound according to [Aspect 1] or [Aspect 2], wherein the heat of fusion measured in accordance with JIS K7122:2012 is 5 to 100 mJ / mg, preferably 8 to 40 mJ / mg, more preferably 10 to 30 mJ / mg, and even more preferably 13 to 25 mJ / mg. 【0015】 [Aspect 4] The acetalized product according to any one of [Aspect 1] to [Aspect 3], wherein the meso / racemo ratio of the acetal ring structure is less than 5, preferably 1.0 or more and less than 5, more preferably 1.2 to 4, even more preferably 1.4 to 3, particularly preferably 1.4 to 2.5, and most preferably 1.4 to 2. 【0016】[Aspect 5] The acetal compound according to any one of [Aspect 1] to [Aspect 4], wherein the haze at a sheet thickness of 0.8 mm, measured in accordance with JIS K7136:2000, is less than 1%, for example, 0.01% or more and less than 1%, preferably 0.01 to 0.6%, more preferably 0.01% or more and less than 0.5%. 【0017】 [Aspect 6] A composition comprising an acetal compound according to any of [Aspect 1] to [Aspect 5] and a plasticizer, wherein the content of the acetal compound is 70% by mass or more, for example 70 to 99% by mass, more preferably 75 to 96% by mass or more, and even more preferably 80 to 90% by mass. 【0018】 [Aspect 7] The composition according to [Aspect 6], wherein the haze at a sheet thickness of 0.8 mm, as measured in accordance with JIS K7136:2000, is less than 1%, for example, 0.01% or more and less than 1%, preferably 0.01 to 0.9%, more preferably 0.01 to 0.8%, and even more preferably 0.01 to 0.7%. 【0019】 [Aspect 8] A resin sheet comprising one or more layers containing an acetal compound according to any of [Aspect 1] to [Aspect 5], or a composition according to [Aspect 6] or [Aspect 7]. 【0020】 [Aspect 9] An interlayer for laminated glass, comprising the resin sheet described in [Aspect 8]. 【0021】 [Aspect 10] Laminated glass including the interlayer for laminated glass described in [Aspect 9]. 【0022】[Aspect 11] A method for producing an acetalized product of an ethylene vinyl alcohol copolymer according to any one of [Aspect 1] to [Aspect 5], comprising the steps of preparing a dispersion containing a solid ethylene vinyl alcohol copolymer and a dispersion medium, and an acetalization step of carrying out an acetalization reaction of the ethylene vinyl alcohol copolymer, wherein the acetalization reaction is carried out by a solid-liquid reaction in the presence of an acidic catalyst, and the concentration of the acidic catalyst after the acetalization reaction is 0.05 mol / L or less, preferably 0.001 to 0.05 mol / L, more preferably 0.005 to 0.04 mol / L, even more preferably 0.01 to 0.03 mol / L, and even more preferably 0.015 to 0.03 mol / L. 【0023】 According to the present invention, it is possible to provide an acetalized ethylene vinyl alcohol copolymer and a resin composition containing said acetalized copolymer that can form a resin sheet with excellent hue, as well as self-supporting properties and creep resistance in high-temperature environments. In this specification, a resin sheet with excellent hue means a resin sheet with suppressed discoloration, or more specifically, a resin sheet with low YI (yellowness). 【0024】 Figure 1 shows the full width at half maximum (FWHM) W. ０．５ｈ Figure 2 shows an example of measurement results from high-performance liquid chromatography (HPLC) to explain the phenomenon. Figure 2 shows an example of measurement results from a titration curve obtained by neutralization titration. 【0025】 The following describes in detail one embodiment of the present invention, but the scope of the present invention is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the invention. Furthermore, if multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range. 【0026】[Acetalized Ethylene Vinyl Alcohol Copolymer] The acetalized ethylene vinyl alcohol copolymer of the present invention refers to an acetalized ethylene vinyl alcohol copolymer having ethylene units in the main chain. Examples of ethylene vinyl alcohol copolymers include those obtained by copolymerizing ethylene with a vinyl ester monomer and saponifying the resulting copolymer. Examples of the ethylene vinyl alcohol copolymer include the ethylene vinyl alcohol copolymer described in the section [Method for Producing Acetalized Products] as a raw material for the acetalized product of the present invention. In this specification, ethylene vinyl alcohol copolymer may be referred to as "EVOH". Also, the acetalized ethylene vinyl alcohol copolymer may be simply referred to as "acetalized product". A resin composition containing the acetalized ethylene vinyl alcohol copolymer may be simply referred to as "resin composition". 【0027】 The acetalized compound contains ethylene units. The ethylene unit content of the acetalized compound is 0.1 to 80 mol%, based on the total monomer units constituting the acetalized compound. When the ethylene unit content is within the above range, it is easier to improve the puncture resistance and self-supporting properties of the resulting resin sheet, particularly its self-supporting properties in high-temperature environments, and the moldability of the acetalized compound. The ethylene unit content is preferably 20 to 60 mol%, more preferably 25 to 55 mol%, even more preferably 30 to 50 mol%, and most preferably 34 to 44 mol%. 【0028】The acetalized material contains vinyl alcohol units. The vinyl alcohol unit content of the acetalized material is 0.1 to 94.9 mol%, based on the total monomer units constituting the acetalized material. From the viewpoint of easily improving glass adhesion, the vinyl alcohol unit content is preferably 30 mol% or more, more preferably 35 mol% or more, and even more preferably 40 mol% or more. From the viewpoint of easily improving puncture resistance and moldability, it is preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less, and particularly preferably 65 mol% or less. The vinyl alcohol unit content is preferably 30 to 80 mol%, more preferably 35 to 75 mol%, even more preferably 40 to 70 mol%, and particularly preferably 40 to 65 mol%. 【0029】 Acetalized compounds contain acetal units. The acetal units in acetalized compounds represent acetalized vinyl alcohol units. The acetal unit content of acetalized compounds is 5 to 50 mol%, based on the total monomer units constituting the acetalized compound. From the viewpoint of easily increasing the transparency of the acetalized compound, the acetal unit content is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 18 mol% or more. From the viewpoint of improving self-supporting properties and creep resistance in high-temperature environments, it is preferably 45 mol% or less, more preferably 35 mol% or less, even more preferably 30 mol% or less, and particularly preferably 25 mol% or less. The acetal unit content is preferably 10 to 45 mol%, more preferably 15 to 35 mol%, even more preferably 18 to 30 mol%, and particularly preferably 18 to 25 mol%. 【0030】The acetalized product may contain vinyl ester units. Examples of vinyl ester units include vinyl acetate units (hereinafter also referred to as "remaining acetic acid groups"). The content of vinyl ester units in the acetalized product, particularly the content of vinyl acetate units (hereinafter also referred to as "amount of remaining acetic acid groups"), is not particularly limited. However, from the perspective of suppressing the deterioration of hue due to deacetylation, it is preferably 10 mol% or less, more preferably 3 mol% or less, still more preferably 1 mol% or less, and particularly preferably 0.5 mol% or less. In one embodiment, from the perspective of hue, it is preferable that the acetalized product does not contain vinyl ester units such as remaining acetic acid groups. 【0031】 The contents of ethylene units, vinyl alcohol units, acetal units, and optionally remaining acetic acid groups in the acetalized product can be determined by NMR measurement, for example, by the method described in the examples. 【0032】 The acetalized product of the present invention has a half-width W ０．５ｈ (hereinafter simply referred to as "half-width W ０．５ｈ ") of 1.10 to 1.35, which is determined by reverse-phase partition gradient high-performance liquid chromatography analysis using a water-ethanol eluent in accordance with JIS K0124:2011. The W ０．５ｈ of the acetalized product is an index representing the distribution of the degree of acetalization in the acetalized product. When the half-width W ０．５ｈ of the acetalized product is less than 1.10, it is difficult to ensure sufficient self-supporting property and creep resistance in a high-temperature environment. Also, when the half-width W ０．５ｈ of the acetalized product exceeds 1.35, coloring occurs during molding, and the hue of the resulting resin sheet tends to deteriorate, so it is difficult to obtain a resin sheet with excellent hue. 【0033】 By setting the half-width W ０．５ｈ of the acetalized product within the above range, although the mechanism by which an acetalized product capable of forming a resin sheet excellent in self-supporting property and creep resistance in a high-temperature environment and excellent in hue can be obtained is not clear, it is considered to be because an appropriate acetalization distribution is imparted to the acetalized product. Specifically, the half-width W ０．５ｈAcetalized compounds with a value of less than 1.10 indicate acetalized compounds with a narrow acetalization distribution. Acetalized compounds with a narrow acetalization distribution have low crystallinity, which tends to reduce their self-supporting ability and creep resistance in high-temperature environments. Also, the full width at half maximum (FWHM) W ０．５ｈ Acetalized compounds with a value greater than 1.35 indicate a broad acetalization distribution. Acetalized compounds with a broad acetalization distribution exhibit high crystallinity and excellent self-supporting properties and creep resistance in high-temperature environments. On the other hand, acetalized compounds with a broad acetalization distribution have a high proportion of low-acetalization regions. Since the low-acetalization region deteriorates and discolors easily due to heat and oxidation, a higher proportion of the low-acetalization region tends to worsen the hue. Therefore, the half-width W is important. ０．５ｈ By setting the ratio to 1.10 to 1.35, the acetalization distribution, such as the ratio of crystallinity to low-acetalization portion of the acetalized material, can be adjusted to an appropriate range. As a result, it is believed that an acetalized material can be obtained that has excellent self-supporting properties and creep resistance in high-temperature environments, as well as excellent coloration, for forming a resin sheet. 【0034】 The full width at half maximum (W) of the acetal compound. ０．５ｈ From the viewpoint of improving hue, as well as self-supporting and creep-resistant properties in high-temperature environments, the half-width W of the acetalized material is preferably 1.13 to 1.34, more preferably 1.14 to 1.33, even more preferably 1.15 to 1.32, and even more preferably 1.20 to 1.30, or 1.22 to 1.29. ０．５ｈ If the value is within the above range, and especially below the upper limit, a resin sheet with low haze and excellent transparency can be formed. 【0035】 In the present invention, the acetal compound W ０．５ｈ This can be determined by reverse-phase partition gradient high-performance liquid chromatography (HPLC) analysis using a water-ethanol eluent, in accordance with JIS K0124:2011. Full width at half maximum (FWHM) W ０．５ｈThis represents the peak width at half the peak height from the baseline of the measured peak obtained by HPLC analysis. Specifically, in the measured peak in Figure 1, which is an example of the measurement result of high-performance liquid chromatography (HPLC), the full width at half maximum (FWHM) W is used. ０．５ｈ The peak width W shown in Figure 1 is shown here. ０．５ｈ This represents the baseline. In Figure 1, the dotted line parallel to the horizontal axis represents the baseline. 【0036】 The above HPLC analysis can be performed using the following measurement conditions and procedure. 【0037】 (HPLC analysis measurement conditions) Sample concentration: 1.5 mg / 1 g Sample solvent: EtOH (99.5%) / ion-exchanged water = 90 / 10 wt% mixed solvent injection volume: 20 μL Detector: Varian 380-LC, EVAP 80°C (pre-heating), NEB 50°C (second-stage heating), Gas 1.5 (SLM), data acquisition interval 1000 msec, filter 1 μm ODS silica column: Shimadzu Corporation "Shimpack G-ODS (octadecyl group modified spherical fully porous silica gel, inner diameter 4 mm × length 10 mm, particle size 5 μm)" Column temperature: 45°C Flow rate: Total flow rate 0.4 mL / min 【0038】 (HPLC Analysis Procedure) Water is used as mobile phase A and ethanol (99.5%) as mobile phase B. Before sample injection, the column of the HPLC system is filled with a mixed solvent of mobile phase A / mobile phase B in a volume ratio of 95 / 5. The sample is then injected. The solvent is then flowed under the following conditions: 0-5 minutes (B concentration: constant 5%) 5-25 minutes (B concentration: 5-100%) 25-30 minutes (B concentration: constant 100%) 30-31 minutes (B concentration: 100-5%) 31-55 minutes (B concentration: constant 5%) 【0039】 The full width at half maximum (W) of the acetal compound. ０．５ｈ This can be adjusted by controlling the distribution of the degree of acetalization by the manufacturing conditions of the acetalized product. For example, by manufacturing the acetalized product using the manufacturing method described later, the full width at half maximum W can be adjusted. ０．５ｈ The range can be adjusted to the aforementioned range. 【0040】 In one embodiment of the present invention, the acetalized material preferably has a melting peak temperature (hereinafter also referred to as "Tm") of 105°C or higher, as measured in accordance with JIS K7121:2012. When the melting peak temperature Tm of the acetalized material is 105°C or higher, it is easier to improve its self-supporting properties and creep resistance in high-temperature environments. Furthermore, it is possible to produce laminated glass with low residual stress. Tm may be, for example, 105 to 180°C, preferably 120 to 170°C, more preferably 130 to 160°C, and even more preferably 135 to 157°C, 140 to 155°C, or 141 to 150°C. 【0041】 In one embodiment of the present invention, the acetalized material may have a glass transition temperature (hereinafter also referred to as "Tg") measured in accordance with JIS K7121:2012, which may be, for example, 0 to 80°C, preferably 10 to 60°C, more preferably 30 to 50°C, and even more preferably 40 to 55°C, 42 to 52°C, or 43 to 49°C. When the glass transition temperature Tg of the acetalized material is within the above range, it becomes easier to achieve both puncture resistance and self-supporting and creep resistance in high-temperature environments. 【0042】 In one embodiment of the present invention, the acetalized material preferably has a heat of fusion (hereinafter also referred to as "ΔH") of 5 to 100 mJ / mg, measured in accordance with JIS K7122:2012, from the viewpoint of improving self-supporting and creep resistance in high-temperature environments. ΔH is preferably 8 to 40 mJ / mg, more preferably 10 to 30 mJ / mg, and even more preferably 13 to 25 mJ / mg, 18 to 24 mJ / mg, or 21 to 23 mJ / mg. In this specification, ΔH represents the heat of fusion of crystals measured using a differential scanning calorimeter (DSC) when the temperature is raised from 25°C to 140°C at a heating rate of 10°C / min, held at 140°C for 30 minutes, then cooled from 140°C to -30°C at a cooling rate of 4°C / min, and then raised again from -30°C to 200°C at a heating rate of 10°C / min. 【0043】In one embodiment of the present invention, the acetalized product preferably has a meso / racemo ratio of less than 5 in its acetal ring structure, from the viewpoint of improving transparency and self-supporting and creep resistance in high-temperature environments. In this specification, the meso / racemo ratio of the acetal ring structure is the ratio of the amount of acetal groups having a mesoacetal ring to the amount of acetal groups having a racemoacetal ring in the stereostructure of the acetal ring. The racemoacetal ring is an acetal ring structure formed from hydroxyl groups having a syndiotactic structure, and the mesoacetal ring is an acetal ring structure formed from hydroxyl groups having an isotactic structure. 【0044】 The meso / racemo ratio is preferably less than 5, more preferably 4 or less, even more preferably 3 or less, particularly preferably 2.5 or less, and most preferably 2 or less, from the viewpoint of improving transparency and self-supporting and creep resistance in high-temperature environments. From the viewpoint of productivity, it is preferably 1.0 or more, more preferably 1.2 or more, and even more preferably 1.4 or more. When the meso / racemo ratio is less than or equal to the above upper limit, the syndiotactic hydroxyl groups are relatively reduced, the hydrogen bonding between hydroxyl groups is reduced, the compatibility with plasticizers is improved, and a moderate crystallinity is imparted to the acetal derivative that can achieve both transparency and self-supporting and creep resistance in high-temperature environments. Thus, it is easier to improve self-supporting and creep resistance in high-temperature environments while maintaining transparency. The meso / racemo ratio is preferably 1.0 or more and less than 5, more preferably 1.2 to 4, even more preferably 1.4 to 3.5, particularly preferably 1.6 to 3.0, most preferably 1.8 to 2.9, 1.9 to 2.8, or 2.0 to 2.5. 【0045】 The aforementioned meso / racemo ratio is, １３ The peak can be determined by performing a 1C-NMR measurement and calculating the intensity ratio of the peak originating from the methine C atom of the acetal portion of a meso-type 6-membered acetal ring and the peak originating from the methine C atom of the acetal portion of a racemo-type 6-membered acetal ring from the obtained spectrum. For example, it can be determined by the method described in the examples. 【0046】 The meso / racemo ratio can be adjusted by appropriately adjusting the degree of acetalization of the acetalized product (i.e., the content of acetal units), the reaction time, the reaction method, and other production conditions for the acetalized product. For example, the meso / racemo ratio can be adjusted to within the above range by producing the acetalized product by a heterogeneous method, for example, by producing the acetalized product by the production method described later. 【0047】 The melt mass flow rate (MFR) of the acetalized material at 190°C and a load of 2.16 kg is, for example, 0.1 to 50 g / 10 min, preferably 1.0 to 20 g / 10 min, more preferably 1.9 to 10 g / 10 min, even more preferably 2 to 8 g / 10 min, and even more preferably 3 to 7 g / 10 min, 3 to 6 g / 10 min, or 3 to 5 g / 10 min. By satisfying this range of MFR, the MFR of the resin composition described later can be adjusted to a suitable range. The MFR can be measured by a method in accordance with JIS K7210-1:2014. 【0048】 The acetalized material preferably has a haze of less than 1% at a sheet thickness of 0.8 mm, for example, 0.01% or more and less than 1%, more preferably 0.8% or less, even more preferably 0.6% or less, and particularly preferably less than 0.5%, from the viewpoint of transparency. Since transparency increases as the haze decreases, the lower limit is not particularly limited and may be, for example, 0.01% or more. The haze of the acetalized material at a sheet thickness of 0.8 mm can be measured using a haze meter in accordance with JIS K7136:2000. Furthermore, the acetalized material with a sheet thickness of 0.8 mm can be prepared by forming the acetalized material into a sheet with a thickness of 0.8 mm, for example, by the method described in the examples. 【0049】The acetalized material preferably has a YI (Yield Inclusion) of 0.01% or more and less than 1.4% at a sheet thickness of 0.8 mm, from the viewpoint of hue. The smaller the YI, the better the hue of the resin sheet. From the viewpoint of even better hue, the YI is preferably 1.3% or less, more preferably 1.1% or less, even more preferably less than 1%, even more preferably 0.8% or less, and particularly preferably 0.5% or less. The YI of the acetalized material at a sheet thickness of 0.8 mm is measured using a haze meter in accordance with JIS K7373. Furthermore, the acetalized material with a sheet thickness of 0.8 mm can be prepared by molding the acetalized material into a sheet with a thickness of 0.8 mm, for example, by the method described in the examples. 【0050】 [Method for Producing Acetalized Products] The method for producing acetalized products of the ethylene vinyl alcohol copolymer of the present invention is not particularly limited and can be produced by known production methods. Examples of methods for producing acetalized products include a method in which the ethylene vinyl alcohol copolymer is dissolved in a solvent and acetalized in a homogeneous solution (homogeneous method), and a method in which a solid ethylene vinyl alcohol copolymer is immersed in an acetalization bath and acetalized in a heterogeneous system (hereinafter also referred to as the heterogeneous method). The heterogeneous method includes a method in which the acetalization reaction is carried out by a solid-liquid reaction and a method in which it is carried out by a dissolution reaction. In this specification, carrying out the acetalization reaction by a solid-liquid reaction means carrying out the reaction without dissolving EVOH and the resulting acetalized product in a solvent (or dispersion medium) during the acetalization reaction. Carrying out the acetalization reaction by a dissolution reaction means carrying out the reaction by dissolving the acetalized product generated as the acetalization reaction progresses in a solvent. 【0051】 The full width at half maximum (W) of the acetal compound. ０．５ｈ From the viewpoint of easily adjusting the ratio to 1.10 or higher and easily improving self-supporting properties and creep resistance in high-temperature environments, it is preferable to manufacture acetalized products by a heterogeneous method, and in particular, it is preferable to carry out the acetalization reaction by a solid-liquid reaction. Furthermore, when carried out by a heterogeneous method, it is easier to adjust the meso / racemo ratio of the acetal ring structure to less than 5. 【0052】A preferred embodiment will be described below. 【0053】 In one embodiment, the acetalized product can be produced by a method comprising the steps of preparing a dispersion containing a solid ethylene vinyl alcohol copolymer and a dispersion medium, and an acetalization step in which the ethylene vinyl alcohol copolymer is subjected to an acetalization reaction. 【0054】 <Dispersion Preparation Process> In the dispersion preparation process, a dispersion containing a solid ethylene vinyl alcohol copolymer and a dispersion medium is prepared. 【0055】 The ethylene vinyl alcohol copolymer is not particularly limited, and examples include those obtained by copolymerizing ethylene with a vinyl ester monomer and saponifying the resulting copolymer. 【0056】 Conventional methods known as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization can be applied to copolymerize ethylene and vinyl ester monomers. Depending on the polymerization method, azo initiators, peroxide initiators, redox initiators, etc., can be appropriately selected as polymerization initiators. For saponification reactions, conventional methods known as alcohol decomposition using alkaline or acid catalysts, hydrolysis, etc., can be applied, and among these, saponification reactions using methanol as a solvent and caustic soda (NaOH) as a catalyst are simple. 【0057】 Examples of vinyl ester monomers used as raw materials for ethylene vinyl alcohol copolymers include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, and vinyl benzoate, but vinyl acetate is particularly preferred. 【0058】 There are no particular restrictions on the degree of saponification of the ethylene vinyl alcohol copolymer, but it is preferably 95 to 100 mol%, more preferably 98 mol% or higher, even more preferably 99 mol% or higher, and particularly preferably 99.9 mol% or higher. 【0059】Ethylene vinyl alcohol copolymers contain ethylene units. The ethylene unit content of an ethylene vinyl alcohol copolymer is, for example, 0.1 to 80 mol%, based on the total monomer units constituting the ethylene vinyl alcohol copolymer. When the ethylene unit content is within the above range, it is easier to improve the puncture resistance and self-supporting properties of the resulting resin sheet, particularly its self-supporting properties under high-temperature environments, and the moldability of the acetalized product. The ethylene unit content is preferably 20 to 60 mol%, more preferably 25 to 55 mol%, even more preferably 30 to 50 mol%, and most preferably 34 to 44 mol%. By ensuring that the ethylene unit content of EVOH is within this range, the ethylene unit content of the acetalized product can be adjusted to a suitable range. 【0060】 The ethylene vinyl alcohol copolymer contains vinyl alcohol units. The vinyl alcohol unit content of the ethylene vinyl alcohol copolymer may be, for example, 20 to 99.9 mol%, preferably 50 to 80 mol%, more preferably 53 to 70 mol%, and particularly preferably 55 to 65 mol%, based on the total monomer units constituting the ethylene vinyl alcohol copolymer. 【0061】 The ethylene vinyl alcohol copolymer may contain vinyl ester units. Examples of vinyl ester units include vinyl acetate units (hereinafter also referred to as "residual acetate groups"). The content of vinyl ester units in the acetalized product, particularly the content of vinyl acetate units (hereinafter also referred to as "residual acetate group amount"), is not particularly limited, but may be, for example, 5 mol% or less, preferably 2 mol% or less, and more preferably 1 mol% or less. From the viewpoint of hue, the ethylene vinyl alcohol copolymer does not need to contain vinyl ester units such as residual acetate groups. 【0062】 The content of ethylene units, vinyl alcohol units, and optionally residual acetate groups in the ethylene vinyl alcohol copolymer can be determined by NMR measurement, for example, by the method described in the examples. 【0063】The melt mass flow rate (MFR) of the ethylene vinyl alcohol copolymer at 190°C and a 2.16 kg load is, for example, 0.1 to 50 g / 10 min, preferably 1 to 20 g / 10 min, and more preferably 5 to 10 g / 10 min. By satisfying this MFR range, the MFR of the resulting acetal and the resin composition described later can be adjusted to a suitable range. The MFR can be measured by a method in accordance with JIS K7210-1:2014. 【0064】 Ethylene vinyl alcohol copolymer has a specific surface area of ​​0.05 m². ２ / g or more, for example, 0.05 to 50 m ２ / g, or 0.1-50m ２ It is preferable that the amount is / g. An ethylene vinyl alcohol copolymer with a large specific surface area, for example, one with a specific surface area of ​​0.05 m², is preferred. ２ By using ethylene vinyl alcohol copolymer at a concentration of 1 / g or more as a raw material, the ethylene vinyl alcohol copolymer can be uniformly acetalized, improving the uniformity of the acetalization reaction. Improved uniformity of the acetalization reaction allows for a narrower acetalization distribution in the resulting acetalized product, thus improving the full width at half maximum (FWHM) of the resulting acetalized product. ０．５ｈ It is easy to adjust this to 1.35 or less. The specific surface area is more preferably 0.5 m². ２ / g or more, more preferably 1m ２ / g or more, more preferably 1.5m ２ / g or more, particularly preferably 5m ２ / g or more, particularly more preferably 10m ２ / g or more, especially more preferably 20m ２ / g, most preferably 30m ２The specific surface area is greater than or equal to / g. The specific surface area can be adjusted by known methods. For example, the specific surface area can be adjusted to above the lower limit by reducing the average particle size of the ethylene vinyl alcohol copolymer by pulverizing or spray-drying the ethylene vinyl alcohol copolymer, or by making the ethylene vinyl alcohol copolymer porous. Note that if the ethylene vinyl alcohol copolymer is a porous material, the pore surface area and the specific surface area of ​​the ethylene vinyl alcohol copolymer are the same. The specific surface area of ​​the ethylene vinyl alcohol copolymer can be measured by a pore distribution measuring device, for example, by the method for measuring pore surface area described in the examples. 【0065】 The ethylene vinyl alcohol copolymer may be a porous body having numerous pores or a non-porous body. If the ethylene vinyl alcohol copolymer is a porous body, it is preferable that some or all of the pores have openings on the surface of the porous body. 【0066】 The method for producing a porous ethylene vinyl alcohol copolymer is not particularly limited and can be produced by known methods. For example, a pellet-shaped porous ethylene vinyl alcohol copolymer can be produced by, for example, the steps described in Japanese Patent Publication No. 11-293077 and Japanese Patent Publication No. 2002-121290, which include the steps of: preparing a composition containing an ethylene vinyl alcohol copolymer and at least one solvent selected from water and alcohol; extruding the composition in a strand shape into a solidification liquid and allowing it to solidify, then cutting the resulting strand-shaped solidified material to a predetermined length with a strand cutter or the like; or directly cutting the composition in a molten state. 【0067】 When the ethylene vinyl alcohol copolymer is a porous body, the median diameter of the pores in the porous body may be, for example, 0.005 to 1 μm. The median diameter improves the uniformity of the acetalization reaction and the full width at half maximum W of the resulting acetalized product. ０．５ｈFrom the viewpoint of easily adjusting to 1.35 or less, it is preferably 0.005 μm or more, more preferably 0.01 μm or more, and even more preferably 0.02 μm or more. Furthermore, the median diameter is preferably 1 μm or less, more preferably 0.5 μm or less, even more preferably 0.2 μm or less, even more preferably less than 0.2 μm, particularly preferably 0.18 μm or less, particularly more preferably 0.15 μm or less, and especially preferably 0.12 μm or less. The median diameter of the pores is the median diameter (d50) for all pores in the range of pore diameter from 0.005 to 100 μm in the log differential pore volume (log differential pore volume) distribution. The reason the pore diameter range for the pore distribution was set to 0.005 to 100 μm is that pore distributions with a pore diameter greater than 100 μm mainly consist of voids between particles, while pore distributions with a pore diameter less than 0.005 μm, which is near the lower limit of measurement, include pseudopores caused by compression, etc. 【0068】 The median diameter of the pores in a porous material can be adjusted by the manufacturing conditions of the porous material. For example, when an ethylene vinyl alcohol copolymer porous material is produced by preparing a composition containing an ethylene vinyl alcohol copolymer and at least one solvent selected from water and alcohol, extruding the composition in a strand shape into a solidification liquid to solidify it, and then cutting the resulting strand-shaped solidified material, the median diameter of the porous material can be adjusted by the type and content of the solvent contained in the composition, the linear velocity when extruding the composition, the extrusion temperature, and the cooling rate. Furthermore, the median diameter of these pores can be measured using a pore distribution measuring device, for example, by the method described in the examples. 【0069】 When the ethylene vinyl alcohol copolymer is a porous material, the pore surface area (specific surface area) of the porous material with a pore diameter in the range of 0.005 to 100 μm, as measured by the mercury intrusion method, is, for example, 25 to 45 m². ２The ratio may be / g, improving the homogeneity of the acetalization reaction, and the full width at half maximum (FWHM) of the resulting acetal product. ０．５ｈ From the viewpoint of easily adjusting to 1.35 or less, 25m is preferable. ２ / g or more, more preferably 30m ２ It is 1 / g or more. Furthermore, the pore surface area is preferably 45m, from the viewpoint of easily suppressing adhesion between ethylene vinyl alcohol copolymer porous bodies during high-temperature washing in the manufacturing process of ethylene vinyl alcohol copolymer porous bodies. ２ / g or less, more preferably 41m ２ / g or less, more preferably 39m ２ It is less than / g. 【0070】 The pore surface area of ​​the ethylene vinyl alcohol copolymer porous body in the 0.005 to 100 μm range can be adjusted by the manufacturing conditions of the porous body. For example, similar to the method for adjusting the median diameter of the pores of the porous body, it can be adjusted by the type and content of the solvent contained in the composition, the linear velocity when extruding the composition into the solidification liquid, the extrusion temperature, and the cooling rate. Furthermore, the pore surface area of ​​the ethylene vinyl alcohol copolymer porous body can be measured using a pore distribution measuring device, for example, by the method described in the examples. 【0071】 When the ethylene vinyl alcohol copolymer is a porous body, the average particle size of the porous body may be preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 3 mm or more, from the viewpoint of handling. Furthermore, the average particle size improves the uniformity of the acetalization reaction and the full width at half maximum W of the resulting acetalized product. ０．５ｈ From the viewpoint of easily adjusting to 1.35 or less, the particle size may be preferably 10 mm or less, more preferably 7 mm or less, and even more preferably 5 mm or less. The average particle size can be measured, for example, by the method described in the examples. 【0072】 When the ethylene vinyl alcohol copolymer is nonporous, the nonporous material improves the uniformity of the acetalization reaction, and the full width at half maximum (FWHM) of the resulting acetalized product is increased. ０．５ｈ From the viewpoint of easily adjusting it to 1.35 or less, a specific surface area above the above lower limit, for example, 0.05 m². ２It is preferable that the specific surface area is greater than or equal to / g, and it is preferable that the specific surface area is increased by known methods, such as wet-ground, dry-ground, or freeze-ground products of ethylene vinyl alcohol copolymer, or spray-dried products of ethylene vinyl alcohol copolymer solutions. 【0073】 When the ethylene vinyl alcohol copolymer is a nonporous material, the average particle size of the nonporous material is preferably, for example, 1 to 500 μm. If the average particle size is below the upper limit, the specific surface area increases, which in turn improves the uniformity of the acetalization reaction and the full width at half maximum (FWHM) of the resulting acetalized product. ０．５ｈ It is easy to adjust this to 1.35 or less. The average particle diameter may be preferably 5 μm or more, and more preferably 10 μm or more, from the viewpoint of ease of handling. Furthermore, the average particle diameter may be preferably 300 μm or less, more preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less, from the viewpoint of facilitating more uniform acetalization of the ethylene vinyl alcohol copolymer. The average particle diameter of the non-porous material can be measured in the same way as the average particle diameter of the porous material. 【0074】 The shape of the ethylene vinyl alcohol copolymer is not particularly limited and can be in the form of powder, pellets, flakes, beads, or irregular shapes. Among these, the shape is preferably powder or pellet, and more preferably pellet. In this invention, the pellet shape refers to a solid porous body having a substantially constant size, such as a spherical, cylindrical, elliptical prism, or polygonal prism, and its cross-section may be circular, elliptical, polygonal, etc. 【0075】 The dispersion medium is not particularly limited, but examples include a mixed solvent of water and an organic solvent. Examples of organic solvents include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetonitrile, acetone, and dimethyl sulfoxide. Methanol, ethanol, acetonitrile, and acetone are particularly preferred as organic solvents from the viewpoint of being easy to remove. More preferably, it is preferable to use only water as the dispersion medium, as this has a low environmental impact. 【0076】The concentration of the ethylene vinyl alcohol copolymer in the dispersion is not particularly limited and can be adjusted as appropriate, but may be, for example, 1 to 50% by mass, preferably 5 to 25% by mass, and more preferably 10 to 20% by mass. 【0077】 <Acetalization Process> In the acetalization process, the solid ethylene vinyl alcohol copolymer contained in the dispersion obtained in the dispersion preparation process is subjected to an acetalization reaction. 【0078】 The acetalization reaction is carried out in the presence of an aldehyde and an acidic catalyst. 【0079】 The aldehyde used in the acetalization reaction is not particularly limited and includes, for example, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, hexylaldehyde, benzaldehyde, isobutyraldehyde, 2-ethylhexylaldehyde, 2-methylbutyraldehyde, trimethylacetaldehyde, 2-methylpentylaldehyde, 2,2-dimethylbutyraldehyde, 2-ethylbutyraldehyde, 3,5,5-trimethylhexylaldehyde, 7-octenal, citral, citronellal, and acro Examples of aldehydes used include lein, crotonaldehyde, 2,3,4-trihydroxybenzaldehyde, 3,4,5-trihydroxybenzaldehyde, 2,4,5-trihydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, and 5-hydroxybenzaldehyde. In terms of heat resistance and optical properties, butyraldehyde, benzaldehyde, and isobutylaldehyde are preferred. These aldehydes may be used individually or in combination of two or more. 【0080】 The amount of aldehyde used is not particularly limited and can be adjusted as appropriate according to the desired degree of acetalization. In one embodiment of the present invention, the amount of aldehyde used is the full width at half maximum W. ０．５ｈFrom the viewpoint of adjusting it to the above range, the amount may be preferably 1 to 45 parts by mass, more preferably 5 to 40 parts by mass, even more preferably 10 to 35 parts by mass, or 10 to 30 parts by mass, per 100 parts by mass of ethylene vinyl alcohol copolymer. 【0081】 In the acetalization step, it is preferable to add an aldehyde to the dispersion obtained in the dispersion preparation step, impregnate at least a portion of the aldehyde into the ethylene vinyl alcohol copolymer, and then add an acidic catalyst (acetalization catalyst) to the dispersion to acetalize the ethylene vinyl alcohol copolymer. By adding the aldehyde to the dispersion before adding the acidic catalyst, and impregnating the ethylene vinyl alcohol copolymer with the aldehyde, which is the acetalizing agent, it becomes easier to uniformly acetalize EVOH. As a result, the full width at half maximum W of the resulting acetalized product ０．５ｈ It is easy to adjust it within the above range. 【0082】 The acetalization reaction is preferably carried out by a solid-liquid reaction in the presence of an acidic catalyst. By carrying out the acetalization reaction by a solid-liquid reaction, it is possible to suppress the excessive narrowing of the acetalization distribution of the resulting acetal, and the full width at half maximum (FWHM) of the resulting acetal is reduced. ０．５ｈ The ratio can be adjusted to 1.10 or higher. The acetalization reaction can be carried out as a solid-liquid reaction by using a poor solvent for the ethylene vinyl alcohol copolymer and the resulting acetalized product as the dispersion medium. The poor solvent for the ethylene vinyl alcohol copolymer and the resulting acetalized product may be a solvent containing water, for example, and preferably water. 【0083】 The acidic catalyst used for the acetalization reaction is not particularly limited, and either an organic or inorganic Brønsted acid may be used. However, it is preferable that the neutralization point of the catalyst determined by the neutralization titration described in the examples does not overlap with the neutralization point of the carboxylic acid, which is the oxidized form of the aldehyde used in the acetalization reaction. Examples of acidic catalysts include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, p-toluenesulfonic acid, and carbonic acid. Inorganic Brønsted acids such as hydrochloric acid, sulfuric acid, and nitric acid are particularly preferred because they are easy to wash off after the reaction, and hydrochloric acid is especially preferred. 【0084】 The method of adding the acidic catalyst is not particularly limited; it may be added all at once, in installments, or sequentially. 【0085】 The acetalization reaction is characterized by the full width at half maximum (W) of the resulting acetal product. ０．５ｈ From the viewpoint of easily adjusting the acid catalyst concentration within the above range, particularly below the upper limit, it is preferable to carry out the reaction at a low acid catalyst concentration. Therefore, the concentration of the acid catalyst after the acetalization reaction is preferably 0.05 mol / L or less, more preferably 0.001 to 0.05 mol / L, even more preferably 0.005 to 0.04 mol / L, and particularly preferably 0.010 to 0.03 mol / L, or 0.015 to 0.03 mol / L. In this specification, the concentration of the acid catalyst after the acetalization reaction refers to the concentration of the acid catalyst immediately after the acetalization reaction, and if the acetalization step includes subsequent steps such as washing, neutralization, or solvent removal, it refers to the concentration of the acid catalyst before these subsequent steps are performed. 【0086】 The concentration of the acidic catalyst after the acetalization reaction is determined by neutralization titration of the acetalization reaction solution. Neutralization titration can be performed using a commercially available automatic titrator, such as the "COM-1760" automatic titrator from HIRANUMA Corporation. A 1 mol / L sodium hydroxide aqueous solution is typically used as the alkali for titration. In the case of an automatic titrator, the neutralization point of the measurement result is displayed as an inflection point on the display device. Figure 2 shows an example of the measurement result of a titration curve obtained by neutralization titration. The amount of titration required to reach the first inflection point is D. １ The concentration of the acid neutralized by the first inflection point is C. １ The amount of titration required up to the second inflection point is D. ２ The concentration of the acid neutralized by the first inflection point is C. ２ In this case, the acid concentration can be calculated using the following formula. Normally, C １ This is the concentration of the acidic catalyst used in the acetalization reaction, and C ２This represents the concentration of the carboxylic acid, which is the oxidized form of the aldehyde used in the acetalization reaction. However, this does not apply if the acidic catalyst used in the acetalization reaction is weaker than the carboxylic acid. Therefore, if a stronger acid than the carboxylic acid is used as the acidic catalyst, such as hydrochloric acid, the C concentration should be calculated by measuring the reaction solution after the acetalization reaction. １ This represents the concentration of the acidic catalyst after the acetalization reaction. 【0087】 C １ = (D １ -B)×F×M / S C ２ = (D ２ -D １ -B) × F × M / S 【0088】 C １ : Acid concentration (moles / L) neutralized by the first inflection point C ２ : Acid concentration (moles / L) neutralized by the second inflection point D １ : Titration volume required to reach the first inflection point (mL) D ２ : Titration volume required to reach the second inflection point (mL) B: Titration volume determined by blank measurement (mL) F: Factor of sodium hydroxide solution M: Concentration of sodium hydroxide solution (mol / L) S: Volume of reaction solution after acetalization reaction measured (mL) 【0089】 The titration volume (mL) B determined by the blank measurement is typically used when the neutralization point is obtained by titrating only the solvent used in the acetalization reaction. If the neutralization point is not obtained, the value should be 0. 【0090】 The factor F and concentration M of the sodium hydroxide aqueous solution should normally be those listed on the purchased reagent, but the factor determined in accordance with JIS K8001 may also be used. 【0091】 If the reaction solution used for the acetalization reaction is a solid-liquid reaction, the volume S of the solution is measured after solid-liquid separation and then a neutralization titration is performed. If it is not a solid-liquid reaction, the volume S of the solution is measured when the ethylene vinyl alcohol copolymer and the acetalized product of the ethylene vinyl alcohol copolymer are mixed together and then a neutralization titration is performed. 【0092】The reaction temperature for acetalization is not particularly limited and may be, for example, 5 to 90°C, preferably 25 to 80°C, more preferably 35 to 70°C, and even more preferably 45 to 65°C. The reaction time for acetalization is also not particularly limited and may be, for example, 0.5 to 50 hours, preferably 2 to 30 hours, and even more preferably 8 to 25 hours. Furthermore, acetalization may be carried out in air or in an inert gas such as nitrogen gas or argon gas, and may be carried out under normal pressure, under pressurized pressure, or under reduced pressure. 【0093】 The method for producing acetalized products may include subsequent steps such as washing, neutralization, and solvent removal after the acetalization step. The presence, order, and number of these steps are not particularly limited. 【0094】 In the neutralization step, the resulting reaction solution is neutralized with an alkali. The alkali used in the neutralization step is not particularly limited and includes, for example, sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium bicarbonate, potassium carbonate, etc. 【0095】The washing step is a step to remove, for example, the acidic catalyst used in the acetalization reaction, the neutralized salt produced in the neutralization step, and the alkali after neutralization. The substances to be removed in one washing step may be at least one of the following: the acidic catalyst, the neutralized salt, and the alkali after neutralization, or two or more. Therefore, the washing step may be performed multiple times depending on the substances to be removed. For example, one or more washing steps may be performed before the neutralization step to mainly remove the acidic catalyst, and one or more washing steps may be performed after the neutralization step to mainly remove the neutralized salt produced in the neutralization step and the alkali after neutralization. Including one or more washing steps before the neutralization step can further improve the hue. There are no particular restrictions on the solvent used as the washing solution in the washing step, but examples include a mixed solvent of water and an organic solvent. Examples of organic solvents include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetonitrile, acetone, and dimethyl sulfoxide. In particular, methanol, ethanol, acetonitrile, and acetone are preferred as mixed solvents from the viewpoint of being easy to remove, and more preferably, only water, which has a low environmental impact, is used as the washing solution. 【0096】 When the acetalization reaction is carried out by a solid-liquid reaction, the acetal obtained as a filtrate by removing the solvent from the reaction solution, for example by filtration, will have the same shape, specific surface area, average particle size, pore structure, etc. as the ethylene vinyl alcohol copolymer used as the raw material. However, its shape and other characteristics can be changed by melt kneading, etc. For example, melt kneading can yield a sheet-shaped, non-porous acetal from a pellet-shaped, porous acetal. Even if the shape and other characteristics are changed by melt kneading, etc. after the acetalization reaction, the content of each unit of the acetal and the full width at half maximum (FWHM) will not change. ０．５ｈ Characteristics such as Tm, Tg, ΔH, and meso / racemo ratio remain unchanged. 【0097】The uses of the acetalized product of the present invention are not particularly limited, and it can be used in various fields, for example, as a packaging material. Such packaging materials can be used, for example, as containers with excellent oxygen barrier properties in the form of bags, tubes, cups, pouches, etc., for food, cosmetics, medical chemicals, toiletries, vacuum insulation boards, etc., or as gas barrier films for food packaging, gasoline tanks, vacuum insulation boards, heat pipes, etc. Furthermore, the acetal compounds of the present invention are also useful as paper processing agents such as fiber adhesives, fiber treatment agents, fiber processing agents, sizing agents for textile products, clear coating agents for paper, pigment coating agents for paper, internal sizing agents for paper, binders for thermal paper overcoats, pressure-sensitive adhesives, anti-fogging agents, paints, dispersants for organic and inorganic pigments, polymerization dispersion stabilizers for emulsions, polymerization dispersion stabilizers for PVC, adhesives for paper, wood and plastics, binders for nonwoven fabrics, binders for fibers, binders for ceramics, binders for electrodes, binders for various building materials such as gypsum board and fiberboard, additives for cement and mortar, hot melt adhesives, interlayer adhesives, resins for 3D printers, etc. In addition, because the acetal compounds of the present invention have high transparency, they are also useful as interlayer films for laminated glass, protective films for glass surfaces, and various transparent containers for cosmetic applications. 【0098】 [Composition] The acetal compound of the present invention may be further enriched with additives such as plasticizers, antioxidants, ultraviolet absorbers, light stabilizers, adhesion modifiers, adhesion improvers, blocking inhibitors, silane coupling agents, pigments, dyes, functional inorganic compounds, and resins other than the acetal compound of the present invention, as needed, to form a composition. Preferably, the composition contains at least a plasticizer as an additive. Therefore, the present invention encompasses compositions containing the acetal compound of the present invention and a plasticizer. 【0099】The composition of the present invention contains the acetal compound of the present invention. The content of the acetal compound of the present invention in the composition of the present invention is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more. When the content of the acetal compound is above the lower limit, transparency, especially hue, and self-supporting properties and creep resistance in high-temperature environments are easily improved. The upper limit is not particularly limited and may be 99% by mass or less. The content of the acetal compound may be, for example, 70 to 99% by mass, more preferably 75 to 96% by mass, and even more preferably 80 to 90% by mass. 【0100】The composition of the present invention contains a plasticizer. Examples of plasticizers include triethylene glycol-di-2-ethylhexanoate, tetraethylene glycol-di-2-ethylhexanoate, di-(2-butoxyethyl)-adipate (DBEA), di-(2-butoxyethyl)-sebacate (DBES), di-(2-butoxyethyl)-azelaic acid, di-(2-butoxyethyl)-glutaric acid, di-(2-butoxyethoxyethyl)-adipate (DBEEA), di-(2-butoxyethoxyethyl)-sebacate (DBEES), di-(2-butoxyethoxyethyl)-azelaic acid, di-(2-butoxyethoxyethyl)-glutaric acid, di-(2-hexoxyethyl)-adipate, di-(2-hex Examples include hexoxyethyl sebacate, di-(2-hexoxyethyl) azelaate, di-(2-hexoxyethyl) glutarate, di-(2-hexoxyethoxyethyl) adipate, di-(2-hexoxyethoxyethyl) sebacate, di-(2-hexoxyethoxyethyl) azelaate, di-(2-hexoxyethoxyethyl) glutarate, di-(2-butoxyethyl) phthalate and / or di-(2-butoxyethoxyethyl) phthalate, polypropylene glycol (PPG), monopropylene glycol dibenzoate, triethylene glycol di-2-ethylhexoate, glycerin mono-12-hydroxystearate, etc. Among these plasticizers, in one embodiment of the present invention, it is preferable that the plasticizer has a sum of 28 or more carbon atoms and oxygen atoms in its molecule.Examples of such plasticizers include triethylene glycol-di-2-ethylhexanoate, tetraethylene glycol-di-2-ethylhexanoate, di-(2-butoxyethyl)-adipate (DBEA), di-(2-butoxyethoxyethyl)-adipate, di-(2-butoxyethoxyethyl)-sebacate, polypropylene glycol (PPG: average molecular weight 400) polyoxyethylene hexyl ether, polyoxyethylene heptyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene allyl ether, polyoxypropylene allyl ether, polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, polyoxyethylene diglyceryl ether, polyoxypropylene diglyceryl ether, polyoxyalkylene pentaerythritol ether, and polycaprolactone triol. These plasticizers may be used individually or in combination of two or more types. 【0101】 In one embodiment of the present invention, the SP value (solubility parameter) of the plasticizer is, for example, 9.2 to 12.0 (cal / cm³). ３ ) １／２ It may be, preferably 9.2 (cal / cm³) ３ ) １／２ More preferably 9.3 (cal / cm³) ３ ) １／２ More preferably 9.5 (cal / cm³) ３ ) １／２ The above is true, and preferably 12.0 (cal / cm³). ３ ) １／２ More preferably, 11.8 (cal / cm³) ３ ) １／２ More preferably, 11.5 (cal / cm³) ３ ) １／２ The following is particularly preferred: 11.2 (cal / cm³) ３ ) １／２The following applies: When the SP value is above the lower limit and / or below the upper limit, it is easier to suppress plasticizer bleed-out and to further improve the puncture resistance of the resulting resin sheet. The SP value is calculated according to Fedors' calculation method (R.F. Fedors, Polym.Eng.Sci., 14, 147 (1947)). 【0102】 The plasticizer content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of acetal, from the viewpoint of easily improving self-supporting properties and creep resistance in high-temperature environments, as well as water resistance, and easily improving adhesion to substrates such as glass, especially low-temperature adhesion. Furthermore, from the viewpoint of easily suppressing plasticizer bleed-out and easily improving puncture resistance, the plasticizer content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 13 parts by mass or more, per 100 parts by mass of acetal. The plasticizer content is preferably 1 to 40 parts by mass, more preferably 5 to 30 parts by mass, even more preferably 10 to 20 parts by mass, and particularly preferably 13 to 20 parts by mass, per 100 parts by mass of acetal. 【0103】 The composition of the present invention may contain additives other than plasticizers. Examples of additives other than plasticizers include antioxidants, ultraviolet absorbers, light stabilizers, adhesion modifiers, adhesion improvers, blocking inhibitors, silane coupling agents, pigments, dyes, and functional inorganic compounds. These additives other than plasticizers may be used individually or in combination of two or more. The composition of the present invention may contain, as additives other than plasticizers, at least one additive selected from the group consisting of antioxidants, ultraviolet absorbers, light stabilizers, adhesion modifiers, adhesion improvers, blocking inhibitors, silane coupling agents, pigments, dyes, and functional inorganic compounds, and preferably at least one additive selected from the group consisting of antioxidants, ultraviolet absorbers, light stabilizers, adhesion modifiers, and adhesion improvers. 【0104】Examples of antioxidants include phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants, with phenolic antioxidants being preferred. These antioxidants may be used individually or in combination of two or more types. 【0105】Examples of phenolic antioxidants include acrylate compounds such as 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate or 2,4-di-t-amyl-6-(1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl)phenyl acrylate, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, octadecyl-3-(3,5-)di-t-butyl-4-hydroxyphenyl)propionate, and 2,2'-methylene-butyl 4-methyl-6-t-butylphenol, 4,4'-butylidene-bis(4-methyl-6-t-butylphenol), 4,4'-butylidene-bis(6-t-butyl-m-cresol), ethylenebis(oxyethylene)bis(3-(5-t-butyl-4-hydroxy-m-tolyl)propionate, 4,4'-thiobis(3-methyl-6-t-butylphenol), bis(3-cyclohexyl-2-hydroxy-5-methylphenyl)methane, 3,9-bis(2-(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate (Nyloxy)-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate)methane, triethylene glycol bis(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate), or alkyl-substituted phenol compounds such as hexamethylenebis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 6-(4-hydroxy-3,5-di-t-butylanilino)-2,4-bis-octylthio-1,3,5-triazine, 6-(4-hydroxy-3,5-dimethylanilino)-2,4-bis-octylthio-1,3,5-triazine, 6-(4-hydroxy-3-methyl-5-t-butylanilino)-2,4-bis-octylthio-1,3,5-triazine or 2-octylthio-4,6-bis-(3,Examples include triazine group-containing phenolic compounds such as 5-di-t-butyl-4-oxyanilino)-1,3,5-triazine, and alkyl-substituted phenolic antioxidants are preferred. These may be used individually or in combination of two or more. 【0106】 Examples of phosphorus-based antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl) phosphite, tris(dinonylphenyl) phosphite, tris(2-t-butyl-4-methylphenyl) phosphite, tris(cyclohexylphenyl) phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. Examples include monophosphite compounds such as 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, and diphosphite compounds such as 4,4'-butylidene-bis(3-methyl-6-t-butylphenyl-di-tridecyl phosphite), 4,4'-isopropylidene-bis(phenyl-di-alkyl(C12-C15) phosphite), 4,4'-isopropylidene-bis(diphenylmonoalkyl(C12-C15) phosphite), 1,1,3-tris(2-methyl-4-di-tridecyl phosphite-5-t-butylphenyl)butane or tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene phosphite. These may be used individually or in combination of two or more. Among these, monophosphite compounds are preferred. 【0107】Examples of sulfur-based antioxidants include dilauryl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, laurylstearyl 3,3'-thiodipropionate, pentaerythritol-tetrakis-(β-lauryl-thiopropionate), and 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane. These may be used individually or in combination of two or more. 【0108】 The antioxidant content in the composition is preferably 0 to 5 parts by mass, more preferably 0.001 to 5 parts by mass, and even more preferably 0.01 to 1 part by mass, per 100 parts by mass of the acetal. 【0109】 Examples of UV absorbers include 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α'dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, Examples include benzotriazole-based ultraviolet absorbers such as 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, or 2-(2-hydroxy-5-t-octylphenyl)benzotriazole, and benzoate-based ultraviolet absorbers such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate or hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate. These may be used individually or in combination of two or more. 【0110】 The amount of ultraviolet absorber in the composition is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 1 part by mass, and even more preferably 0.1 to 0.5 parts by mass, relative to the acetal. 【0111】Examples of light stabilizers include hindered amine compounds such as 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate, 4-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)-1-(2-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl)-2,2,6,6-tetramethylpiperidine, or bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidine) sebacate. These may be used individually or in combination of two or more. 【0112】 Adhesion modifiers are additives that reduce adhesive strength. Examples of adhesion modifiers include those disclosed in International Publication No. 03 / 033583, preferably alkali metal salts and / or alkaline earth metal salts of organic acids. More preferably, they may be potassium salts, magnesium salts, or calcium salts of carboxylic acids having 1 to 16 carbon atoms, such as potassium acetate, magnesium acetate, magnesium propionate, magnesium butyrate, magnesium 2-ethylbutyrate, magnesium 2-ethylhexanoate, magnesium octoate, magnesium decanoate, magnesium neodecanoate, or calcium stearate. These may be used individually or in combination of two or more. 【0113】 Examples of adhesion enhancers include silane coupling agents. Examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyldiethoxysilane. These silane coupling agents may be used individually or in combination of two or more. 【0114】If the composition contains an adhesion modifier or adhesion improver, its content should be appropriately selected depending on the type of adhesion improver (adhesion modifier, adhesion improver) and the environment in which the laminated glass is used when the composition is used as an interlayer raw material for laminated glass. For example, the content of the adhesion improver is preferably adjusted so that the adhesion strength of the resulting resin sheet to glass is generally 3 to 10 in the Pummel test (described in International Publication No. 03 / 033583, etc.), and is preferably adjusted to 3 to 6 when high penetration resistance is required, and to 7 to 10 when high glass shatter resistance is required. When high glass shatter resistance is required, it is also a useful method not to add an adhesion improver. If the composition contains an adhesion improver, its content may preferably be 0.001 to 5 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of acetal. 【0115】 The content of various additives other than plasticizers can be appropriately selected within a range that does not impair the effects of the present invention, and the total content of various additives other than plasticizers may be, for example, 0.01 to 10% by mass, preferably 7% by mass or less, more preferably 5% by mass or less, and even more preferably 4% by mass or less, based on the total mass of the composition. 【0116】The composition of the present invention may contain resins other than the acetal compound of the present invention. The resins other than the acetal compound of the present invention are not particularly limited and include, for example, polyolefin resins such as polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, and polynorbornene; ethylene-based ionomers; styrene-based resins such as polystyrene, styrene-maleic anhydride copolymer, high-impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, and MBS resin; methyl methacrylate polymers and methyl methacrylate-styrene copolymers; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; nylon 6 and nylon 66. Examples include polyamides such as polyamide elastomers; polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyacetal, polyvinylidene fluoride, polyurethane, modified polyphenylene ether, polyphenylene sulfide, silicone-modified resin, acrylic rubber, acrylic thermoplastic elastomer, silicone rubber; styrene-based thermoplastic elastomers such as SEPS, SEBS, and SIS; olefin-based rubbers such as IR, EPR, and EPDM; ethylene vinyl alcohol copolymers and acetalized ethylene vinyl alcohol copolymers other than the acetalized product of the present invention. These resins may be used individually or in combination of two or more types. 【0117】 The content of the resin other than the acetal in the present invention may be, for example, 1 to 25 parts by mass or 5 to 25 parts by mass per 100 parts by mass of the acetal, and is 25 parts by mass or less from the viewpoint of easily improving the self-supporting and creep resistance of the resulting resin sheet in a high-temperature environment. Furthermore, from the viewpoint of increasing the fluidity of the composition and easily improving moldability, the content may be, for example, 0 parts by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more, per 100 parts by mass of the acetal. 【0118】The method for producing the compositions of the present invention is not particularly limited, and they can be produced by adding a plasticizer, an additive other than a plasticizer, and a resin other than the acetal of the present invention to the acetal of the present invention by known methods. For example, as an addition method, kneading by melt kneading is preferable, and this can be done by supplying the acetal of the present invention, a plasticizer, and optionally the above-mentioned additives and a resin other than the acetal of the present invention to a known mixing or kneading device such as a kneader-ruder, extruder, mixing roll, or Banbury mixer. The temperature when kneading these compositions is not particularly limited, but is usually between 120°C and 280°C. 【0119】 The MFR of the composition at 190°C and a 2.16 kg load is, for example, 1 to 50 g / 10 min, preferably 2 to 30 g / 10 min, more preferably 3 to 30 g / 10 min, 4 to 28 g / 10 min, 5 to 25 g / 10 min, 10 to 25 g / 10 min, 15 to 22 g / 10 min, 17 to 21 g / 10 min, or 18 to 21 g / 10 min. If the MFR is less than 1 g / 10 min, sufficient processability (fluidity) cannot be obtained within the appropriate molding temperature range during molding, requiring an increase in the molding temperature, and as a result, the resulting molded article tends to be prone to discoloration. If the MFR exceeds 50 g / 10 min, sufficient melt tension cannot be obtained within the appropriate molding temperature range during molding, and problems such as deterioration of film formation stability and surface texture of the molded article tend to occur. 【0120】 In one embodiment of the present invention, the composition may have a melting peak temperature Tm, measured in accordance with JIS K7121:2012, preferably 100 to 170°C, more preferably 120 to 160°C, even more preferably 130 to 155°C, 137 to 153°C, 141 to 149°C, or 143 to 148°C. When Tm is within the above range, it is easier to improve the self-supporting and creep-resistant properties of the resulting resin sheet in high-temperature environments. Furthermore, it is possible to produce laminated glass with low residual stress. 【0121】In one embodiment of the present invention, the composition may have a glass transition temperature Tg measured in accordance with JIS K7121:2012, for example, -10 to 60°C, preferably 0 to 45°C, more preferably 5 to 35°C, and even more preferably 10 to 30°C, 17 to 29°C, 19 to 28°C, 20 to 27°C, or 21 to 25°C. When the glass transition temperature Tg of the composition is within the above range, it becomes easier to achieve both puncture resistance and self-supporting and creep resistance in high-temperature environments. 【0122】 In one embodiment of the present invention, the composition is preferably such that, from the viewpoint of improving self-supporting and creep resistance in high-temperature environments, the heat of fusion ΔH measured in accordance with JIS K7122:2012 is, for example, 5 to 40 mJ / mg. ΔH is preferably 10 to 30 mJ / mg, more preferably 12 to 25 mJ / mg, and even more preferably 14 to 21 mJ / mg, 15 to 20 mJ / mg, or 18 to 20 mJ / mg. 【0123】 In one embodiment, the composition exhibits the same haze and YI values ​​at a sheet thickness of 0.8 mm as those of the resin sheet of the present invention described in the section on [resin sheet] below. 【0124】The uses of the composition of the present invention are not particularly limited, and it can be used in various fields, for example, as a packaging material. Such packaging materials can be used, for example, as containers with excellent oxygen barrier properties in the form of bags, tubes, cups, pouches, etc., for food, cosmetics, medical chemicals, toiletries, vacuum insulation boards, etc., or as gas barrier films for food packaging, gasoline tanks, vacuum insulation boards, heat pipes, etc. Furthermore, the compositions of the present invention are also useful as paper processing agents such as fiber adhesives, fiber treatment agents, fiber processing agents, sizing agents for textile products, clear coating agents for paper, pigment coating agents for paper, internal sizing agents for paper, binders for thermal paper overcoats, pressure-sensitive adhesives, anti-fogging agents, paints, dispersants for organic and inorganic pigments, polymerization dispersion stabilizers for emulsions, polymerization dispersion stabilizers for PVC, adhesives for paper, wood and plastics, binders for nonwoven fabrics, binders for fibers, binders for ceramics, binders for electrodes, binders for various building materials such as gypsum board and fiberboard, additives for cement and mortar, hot melt adhesives, interlayer adhesives, resins for 3D printers, etc. In addition, because the compositions of the present invention have high transparency, they are also useful as interlayers for laminated glass, protective films for glass surfaces, and various transparent containers for cosmetic applications. 【0125】 [Resin Sheet] The present invention also includes resin sheets comprising one or more layers containing the acetal compound or composition of the present invention. The resin sheet of the present invention may consist only of layers (x) containing the acetal compound or composition of the present invention, or it may be a multilayer film (laminated) comprising at least one layer (x). The multilayer film is not particularly limited, but examples include a two-layer film in which layer (x) and other layers are laminated, or a three-layer film in which other layers are arranged between two layers (x). When layer (x) or other layers are multiple layers, the resin or resin composition constituting each layer may be the same or different. 【0126】Other layers include layers containing known resins. Examples of such resins include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polytetrafluoroethylene, acrylic resin, polyamide, polyacetal, polycarbonate, and among polyesters, polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, polyarylate, liquid crystal polymer, and polyimide. The other layers may also contain additives such as plasticizers, antioxidants, ultraviolet absorbers, light stabilizers, antiblocking agents, pigments, dyes, heat-shielding materials (e.g., inorganic or organic heat-shielding materials with infrared absorption capabilities), and functional inorganic compounds, as needed. 【0127】 In order to prevent the resin sheets of the present invention from adhering to each other and to improve degassing during the lamination process, it is preferable to have irregularities on the surface of the resin sheet. Conventional known methods can be used to create the irregularities, such as a method of creating a melt fracture structure by adjusting the extrusion conditions, or a method of imparting an embossed structure to the extruded sheet. Conventional known methods can be used for the depth and shape of the embossing. 【0128】 The thickness of one layer (x) in the resin sheet is preferably 0.1 to 3.0 mm, or 0.1 to 2.5 mm, more preferably 0.4 to 2.0 mm, even more preferably 0.7 mm to 1.5 mm, and particularly preferably 0.7 mm to 1.0 mm. If the resin sheet consists of multiple layers (x), the thickness of each of the multiple layers (x) in the resin sheet may be the same or different. 【0129】The thickness of the resin sheet of the present invention is not particularly limited, but is preferably 0.1 to 3.0 mm, or 0.1 to 2.5 mm, more preferably 0.4 to 2.0 mm, even more preferably 0.7 mm to 1.5 mm, and particularly preferably 0.7 mm to 1.0 mm. If the resin sheet is thinner than 0.10 mm, it tends to be difficult to satisfy the penetration resistance performance of the laminated glass, and if it is thicker than 3.0 mm, the cost of the sheet itself is high, and the cycle time of the lamination process also tends to be long, which is undesirable. The resin sheet may be used as a single molded sheet, or two or more molded sheets can be stacked to adjust to the desired thickness. 【0130】 The thickness of one layer (x) in a resin sheet and the thickness of the resin sheet are measured using conventionally known methods, such as contact or non-contact thickness gauges. 【0131】 The resin sheet of the present invention has a storage modulus (E') of, for example, 9 to 100 MPa, preferably 10 to 50 MPa, and more preferably 12 to 30 MPa, under the conditions of a measurement temperature of 80°C and a frequency of 1 Hz. When the storage modulus (E') is within the above range, the self-supporting properties in high-temperature environments are good. The storage modulus (E') can be measured by a method in accordance with JIS K0129:2005. 【0132】 Regarding the resin sheet of the present invention, when a master curve was created at 50°C, the result was 3.2 × 10 ８ The long-term relaxation modulus after 2 seconds (approximately 10 years) is preferably 0.5 MPa or more, more preferably 1.0 MPa or more, even more preferably 1.5 MPa or more, and particularly preferably 2.0 MPa or more. The upper limit of the long-term relaxation modulus is not particularly limited, but may be, for example, 20 MPa or less. When the long-term relaxation modulus is within the above range, creep resistance is further improved. The long-term relaxation modulus can be measured by the method described in the examples. In one embodiment, the long-term relaxation modulus may be, for example, 0.5 to 20 MPa, preferably 1.0 to 20 MPa, more preferably 1.5 to 10 MPa, and even more preferably 2.0 to 5.0 MPa. 【0133】The penetration energy of the resin sheet of the present invention is preferably 10 to 30 J, more preferably 12 to 25 J, and even more preferably 14 to 20 J. The penetration energy can be measured in accordance with ASTM D3763 using a drop-weight impact tester, for example, by the method described in the examples. 【0134】 The YI of the resin sheet of the present invention, with a sheet thickness of 0.8 mm, is 0.01% or more and less than 1.4%. The smaller the YI, the better the hue of the resin sheet. From the viewpoint of even better hue, the YI is preferably 1.3% or less, more preferably 1.1% or less, and even more preferably less than 1%. The YI of the resin sheet is measured using a haze meter in accordance with JIS K7373. 【0135】 The haze of the resin sheet of the present invention with a sheet thickness of 0.8 mm may be 0.01% or more and less than 1%. The smaller the haze, the better the transparency of the resin sheet. From the viewpoint of achieving better transparency, the haze is preferably 0.9% or less, more preferably 0.8% or less, and even more preferably 0.7% or less. The haze of the resin sheet is measured using a haze meter in accordance with JIS K7136:2000. 【0136】 There are no particular limitations on the method for producing the resin sheet of the present invention, and known methods can be used. Specifically, the acetalized material or composition can be formed into a sheet by extrusion molding, press molding, blow molding, injection molding, solution casting, etc. In particular, a method is preferred in which the acetalized material, composition, and additives are supplied to an extruder, kneaded, melted, discharged from a die, and taken up by a take-up machine to form a plate. The resin temperature during extrusion is preferably 130 to 230°C, more preferably 140 to 220°C, and even more preferably 150 to 200°C. By keeping the resin temperature within the above range, the decomposition of the acetalized material is suppressed, and a resin sheet with excellent color can be obtained. Furthermore, in order to efficiently remove volatile substances, it is preferable to remove volatile substances by reducing the pressure from the vent port of the extruder. 【0137】[Interlayer for Laminated Glass] The resin sheet of the present invention is useful as an interlayer for laminated glass (hereinafter also simply referred to as an interlayer). This interlayer for laminated glass is particularly preferred as an interlayer for laminated glass for structural materials due to its excellent adhesion to substrates such as glass, transparency, and self-supporting properties. Furthermore, it is suitable not only as an interlayer for laminated glass for structural materials, but also as an interlayer for laminated glass in various applications such as mobile bodies such as automobiles, buildings, and solar cells. In addition, due to its adhesion to various substrates, it is also useful as an adhesive or interlayer adhesive for paper, wood, and plastics, as well as a protective film for glass surfaces, but its applications are not limited to these. 【0138】 [Laminated Glass] Laminated glass can be produced by inserting and laminating the resin sheet of the present invention between two or more sheets of glass, including inorganic glass or organic glass. There are no particular restrictions on the glass to be laminated with the interlayer for laminated glass of the present invention, but in addition to inorganic glass such as float glass, tempered glass, wired glass, and heat-absorbing glass, conventionally known organic glass such as polymethyl methacrylate and polycarbonate can be used. There are no particular restrictions on the thickness of the glass, but 1 to 10 mm is preferred, and 2 to 6 mm is more preferred. 【0139】 The laminated glass of the present invention can be manufactured by conventionally known methods. Examples include methods using a vacuum laminator, a vacuum bag, a vacuum ring, or a nip roll. Additionally, a method of immersion in an autoclave after temporary bonding can also be performed. 【0140】 When using a nip roll, for example, one method is to perform the first temporary bonding at a temperature below the flow initiation temperature of the resin composition, and then perform another temporary bonding under conditions close to the flow initiation temperature. Specifically, for example, one method is to heat to 30 to 70°C with an infrared heater, then degas with a roll, and then heat again to 50 to 120°C before pressing and bonding or temporary bonding with a roll. 【0141】 The autoclave process, which is performed as an additional step after the initial bonding, is carried out for approximately 2 hours at a temperature of 130 to 145°C under a pressure of approximately 1 to 1.5 MPa, although this varies depending on the thickness and configuration of the module and laminated glass. 【0142】 The laminated glass containing the resin sheet of the present invention has excellent hue. The YI of the laminated glass of the present invention is preferably 0.01 to 2.5, more preferably 2 or less, even more preferably 1.5 or less, and even more preferably 1.2 or less. The smaller the YI, the better the hue of the laminated glass. The YI of the laminated glass is measured using a haze meter in accordance with JIS K7373. 【0143】 The laminated glass containing the resin sheet of the present invention has excellent transparency. The haze of the laminated glass of the present invention is preferably 0.01 to 1.2%, more preferably 1.1% or less, and even more preferably 1% or less. The smaller the haze, the better the transparency of the laminated glass. The haze of the laminated glass is measured using a haze meter in accordance with JIS K7136:2000. 【0144】 The laminated glass of the present invention has excellent transparency, hue, penetration resistance, and heat resistance, and can therefore be suitably used in automotive windshields, automotive side windows, automotive sunroofs, automotive rear windows, head-up display glass, laminates for facades, exterior walls and roofs, panels, doors, windows, walls, roofs, sunroofs, soundproof walls, display windows, balconies, railing walls and other building materials, partition glass members for conference rooms, solar panels, and the like. 【0145】 The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto. 【0146】 The measurement and evaluation methods are described below. 【0147】 [Measurement Method] <Content of Each Monomer Unit> The ethylene vinyl alcohol copolymer used as a raw material in the Examples and Comparative Examples, and the acetalized ethylene vinyl alcohol copolymer obtained in the Examples and Comparative Examples, were analyzed for the content (degree of acetalization) (unit: mol%) of ethylene units, vinyl alcohol units, and acetal units, which are acetalized vinyl alcohol units, in the ethylene vinyl alcohol copolymer and its acetalized product as follows. 【0148】 Ethylene vinyl alcohol copolymer was dissolved in dimethyl sulfoxide (DMSO) (manufactured by Kanto Chemical Co., Ltd.) at 120°C, and the resulting DMSO solution was cooled to room temperature. Then, N,N-dimethyl-4-aminopyridine and acetic anhydride (both manufactured by Tokyo Chemical Industry Co., Ltd.) were added to the DMSO solution and stirred for 1 hour to react. The copolymer was reprecipitated from the resulting reaction solution using deionized water and acetone, washed, and then dried to obtain ethylene vinyl acetate copolymer. The obtained ethylene vinyl acetate copolymer was then converted to deuterated dimethyl sulfoxide (DMSO-d ６ The sample was dissolved in (manufactured by Kanto Chemical Co., Ltd.) and measured using a 400 MHz proton NMR analyzer with 256 cumulative measurements. From the obtained spectrum, the content of ethylene units (n) relative to the total monomer units constituting the ethylene vinyl alcohol copolymer was calculated from the intensity ratio of the methine proton peaks (peaks of 1.1 to 1.9 ppm) derived from ethylene units and vinyl acetate units, and the terminal methyl proton peak (peak of 2.0 ppm) derived from vinyl acetate units in the ethylene vinyl acetate copolymer. 【0149】 Since ethylene units are not affected by the acetalization reaction, the ethylene unit content (n) in an ethylene vinyl alcohol copolymer is equal to the ethylene unit content (n) relative to the total monomer units constituting the acetalized product of the ethylene vinyl alcohol copolymer obtained after acetalization of the ethylene vinyl alcohol copolymer. 【0150】 The content of vinyl alcohol units (l), vinyl acetate units (m), and acetal units (k) relative to the total monomer units constituting the acetalized product of ethylene vinyl alcohol copolymer was determined by the following method. DMSO-d acetalized product of ethylene vinyl alcohol copolymer ６The solution was measured using a 400 MHz proton NMR analyzer with 256 cumulative measurements. From the obtained spectra, the intensity ratios of the methine proton peaks (peaks from 1.0 to 1.8 ppm) derived from ethylene units, vinyl alcohol units, and vinyl acetate units, and the terminal methyl proton peaks (peaks from 0.8 to 1.0 ppm) derived from acetal units, as well as the ethylene unit content (n) of the ethylene vinyl alcohol copolymer, were used to calculate the content of each monomer unit. 【0151】 <Half-width (W) ０．５ｈ )> Full width at half maximum W of the acetal compounds obtained in the examples and comparative examples ０．５ｈ The full width at half maximum (FWHM) was determined by reverse-phase partition gradient high-performance liquid chromatography (HPLC) analysis using a water-ethanol eluent under the following conditions, in accordance with JIS K0124:2011. ０．５ｈ This represents the peak width at half the peak height from the baseline of the measured peak obtained by HPLC analysis. 【0152】 (HPLC analysis measurement conditions) Sample concentration: 1.5 mg / 1 g Sample solvent: EtOH (99.5%) / ion-exchanged water = 90 / 10 wt% mixed solvent injection volume: 20 μL Detector: Varian 380-LC, EVAP 80°C (pre-heating), NEB 50°C (second-stage heating), Gas 1.5 (SLM), data acquisition interval 1000 msec, filter 1 μm ODS silica column: Shimadzu Corporation "Shimpack G-ODS (octadecyl group modified spherical fully porous silica gel, inner diameter 4 mm × length 10 mm, particle size 5 μm)" Column temperature: 45°C Flow rate: Total flow rate 0.4 mL / min 【0153】(Procedure for HPLC analysis) Water was used as mobile phase A and ethanol (99.5%) as mobile phase B. Before sample injection, the inside of the column of the HPLC system was filled with a mixed solvent of mobile phase A / mobile phase B at a volume ratio of 95 / 5. The sample was injected in this state. Then, the solvent was flowed under the following conditions. 0 - 5 minutes (B concentration; constant at 5%) 5 - 25 minutes (B concentration; 5 - 100%) 25 - 30 minutes (B concentration; constant at 100%) 30 - 31 minutes (B concentration; 100 - 5%) 31 - 55 minutes (B concentration; constant at 5%) 【0154】 <Glass transition temperature Tg and melting peak temperature Tm> The acetalized product or resin composition obtained in the examples and comparative examples was heated from 25°C to 230°C at a heating rate of 10°C / min using a differential scanning calorimeter (DSC) (TGA / DSC1 Star System manufactured by Mettler Toledo) to melt the sample, cooled from 230°C to -30°C at a cooling rate of 10°C / min, and then heated again from -30°C to 230°C at a heating rate of 10°C / min. The melting peak temperature Tm (°C) and the midpoint glass transition temperature Tg (°C) were measured in accordance with JIS K7121:2012. 【0155】 <Heat of fusion ΔH> The acetalized product or resin composition obtained in the examples and comparative examples was heated from 25°C to 230°C at a heating rate of 10°C / min using a differential scanning calorimeter (DSC) (TGA / DSC1 Star System manufactured by Mettler Toledo) to melt the sample, cooled from 230°C to -30°C at a cooling rate of 10°C / min, and then heated again from -30°C to 230°C at a heating rate of 10°C / min. The heat of fusion (ΔH) was measured in accordance with JIS K7122:2012. 【0156】 <Meso / racemo ratio (m / r ratio)> Using a Bruker spectrometer AV600 type, １３ 13C-NMR measurement was carried out. In a 10 mm diameter NMR tube, the acetalized product obtained in the examples and comparative examples was dissolved in deuterated dimethyl sulfoxide (DMSO-d ６A 12% by mass acetal solution was prepared by dissolving the acetal in ). 0.9% by mass of chromium(III) acetylacetonate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added as a mitigating agent. NMR measurements were performed at 80°C in gate decoupling mode. From the obtained spectra, the meso / racemo ratio was calculated from the intensity ratio of the peaks originating from the methine C atoms of the acetal portion of the meso-type six-membered acetal ring (peaks from 98.0 to 102 ppm) and the peaks originating from the methine C atoms of the acetal portion of the racemo-type six-membered acetal ring (peaks from 91.0 to 95.0 ppm). 【0157】 <Melt Mass Flow Rate (MFR)> The melt mass flow rates of the ethylene vinyl alcohol copolymers used in the examples and comparative examples, the acetalized products and resin compositions obtained in the examples and comparative examples were measured in accordance with JIS K7210-1:2014 under conditions of 190°C and a 2.16 kg load. 【0158】 <Average Particle Size> For 100 g of ethylene vinyl alcohol copolymer obtained in Production Examples 1 to 6 described below, the average particle size of the measurement sample (porous pellets of freeze-dried ethylene vinyl alcohol copolymer) was measured using the "CAMSIZER XT" from Verder Scientific. The average particle size was defined as the particle size at which the cumulative particle size distribution from the smallest particle size side of the circle equivalent particle size calculated by dynamic image analysis in accordance with ISO 13322-2 (2006) was 50% (by volume) (Q3 50.0%). 【0159】<Median pore diameter, pore surface area (specific surface area)> The porous body of the ethylene-vinyl alcohol copolymer obtained in each of the production examples described below or the acetalized product obtained in the examples and comparative examples was freeze-dried at -80°C, and then 0.5 g was taken into a standard 5 cc powder cell (stem volume 0.4 cc). Under the condition of an initial pressure of 2.6 kPa, using a micromeritics pore size distribution measuring device (manufactured by Shimadzu Corporation, Autopore V9620), the median pore diameter and pore surface area of pores within the range of 0.005 to 100 μm in pore diameter were measured. The median pore diameter is the median diameter (d50) for all pores within the range of 0.005 to 100 μm in pore diameter in the Log differential pore volume distribution. The mercury parameters were a mercury contact angle of 130 degrees and a mercury surface tension of 485 dynes / cm. For the non-porous body of the ethylene-vinyl alcohol copolymer obtained in Production Example 7, voids between particle sizes were detected, and the specific surface area could not be calculated in the above measurement. Therefore, the specific surface area was calculated from the average particle diameter obtained in the measurement of <average particle diameter> described above. 【0160】 <Acidic catalyst concentration after acetalization reaction> The acidic catalyst concentration after the acetalization reaction was carried out by a solid-liquid reaction was determined by neutral titration of the reaction solution after the acetalization reaction. The neutral titration was carried out using an automatic titrator "COM-1760" of Hiranuma Co., Ltd. As the alkali for titration, a 1 mol / L aqueous sodium hydroxide solution was used. By the automatic titrator, the neutralization point of the measurement result was displayed as an inflection point on the display device. From the displayed inflection point, the titration volume (mL) D １ required to reach the first inflection point was determined. The acid concentration (mol / L) C １ neutralized up to the first inflection point was defined as the concentration of the acidic catalyst used in the acetalization reaction, and C １ was calculated from the following formula. 【0161】 The acidic catalyst concentration C after the acetalization reaction １ =(D １ -B)×F×M / S C １ : Acid concentration (mol / L) neutralized up to the first inflection point D １: Titration volume required to reach the first inflection point (mL) B: Titration volume determined by blank measurement (mL) = 0 (mL) F: Factor of sodium hydroxide aqueous solution = 1.000 M: Concentration of sodium hydroxide aqueous solution (mol / L) = 1 (mol / L) S: Volume of reaction solution after acetalization reaction measured (mL) = 50 (mL) 【0162】 [Evaluation Method] <Self-supporting properties under high-temperature conditions (storage modulus at 80°C)> The self-supporting properties of the resin sheets obtained in the examples and comparative examples under high-temperature conditions were evaluated by the storage modulus at 80°C. Test pieces measuring 20 mm in length and 5 mm in width were cut from the resin sheets obtained in the examples and comparative examples, and the storage modulus (E') was measured using a dynamic viscoelasticity measuring device (manufactured by UBM Co., Ltd.) under the conditions of a measurement temperature of 80°C and a frequency of 1 Hz. 【0163】 <Creep Resistance in High-Temperature Environments (Long-Term Relaxation Modulus)> The creep resistance of the resin sheets obtained in the examples and comparative examples in high-temperature environments was evaluated by determining the long-term relaxation modulus. After leaving the resin sheets obtained in the examples and comparative examples to stand in a 23°C, 50% RH atmosphere for more than one week, a 40 mm x 5 mm test piece was cut out, and the long-term relaxation modulus was determined from a composite curve (master curve) at a reference temperature of 50°C, obtained from dynamic viscoelasticity measurement and the time-temperature conversion rule, using a dynamic viscoelasticity measuring device manufactured by UBM Co., Ltd. This value was used as an indicator of the strength of the resin sheet after a long period of time. A higher long-term relaxation modulus indicates higher strength of the resin sheet after a long period of time. 【0164】 Dynamic viscoelasticity measurements were performed according to the method compliant with JIS K0129:2005, with tensile measurements conducted under conditions of temperature 50-100°C and frequencies of 0.1, 0.5, 1, 5, 10, 50, and 100 Hz. From the obtained storage modulus measurement results, a master curve was created using the temperature-time conversion rule, with the reference temperature set to 50°C, and the frequency was set to 3.2 × 10⁻⁶. －９ Storage modulus (E'(t1)) at Hz, and frequency 1.6 × 10 －９ The loss modulus of elasticity (E''(t²)) at Hz is read, Poisson's ratio is fixed at 0.5, and the following formula (A) is used: 50°C, 3.2 × 10 ８The relaxation modulus G(t) after 2 seconds was calculated. G(t) = E'(t1) / 3 - 0.4 × E''(t2) / 3 ... (A) These calculations were performed using the calculation software "RheoStation" (UBM Corporation) attached to the dynamic viscoelasticity measuring device manufactured by UBM Corporation. 【0165】 <Penetration Resistance (Penetration Energy)> Penetration resistance was evaluated by penetration energy. The molten kneaded acetalized or resin composition obtained in the examples and comparative examples was heated at 200°C and subjected to a penetration energy of 50 kgf / cm². ２ A 0.8 mm thick resin sheet was obtained by compression molding at a pressure of 5 minutes. A 60 mm x 60 mm test piece was cut from the resin sheet, and a drop-weight impact test was performed using an Instron "CEAST9350" machine in accordance with ASTM D3763-18, under the conditions of a measurement temperature of 23°C, a load of 2 kg, and an impact velocity of 9 m / sec. The penetration energy was calculated from the area of ​​the SS curve from the moment the striker tip touched the test piece (sensing the test force) to the moment of penetration (when the test force returned to zero). 【0166】 <Transparency> (YI and haze of resin sheets) Test specimens measuring 50 mm in length and 50 mm in width were cut from the resin sheets obtained in the examples and comparative examples. The YI of the obtained test specimens was measured in accordance with JIS K7373 using a haze meter (SH7000, manufactured by Nippon Denshoku Industries Co., Ltd.). The haze of the obtained test specimens was measured in accordance with JIS K7136:2000 using the same apparatus as for the YI measurement. 【0167】 (YI and haze of laminated glass) The YI of the laminated glass obtained in the examples and comparative examples was measured in accordance with JIS K7373 using a haze meter (SH7000, manufactured by Nippon Denshoku Industries Co., Ltd.). The haze of the obtained laminated glass was measured in accordance with JIS K7136:2000 using the same apparatus as for the YI measurement. 【0168】 In the examples and comparative examples, pelletized ethylene vinyl alcohol copolymers (EVOH1 to EVOH8) produced by the following methods were used as raw materials, respectively. 【0169】<Production Example 1> An ethylene vinyl alcohol copolymer solution containing 100 parts by mass of ethylene vinyl alcohol copolymer with an ethylene unit content of 32 mol% and a degree of saponification of 99.98 mol%, 60 parts by mass of methanol, and 40 parts by mass of water was continuously supplied from the top of a 10-stage tray column with a column diameter of 0.3 m, and steam was blown in from the bottom of the column to bring the ethylene vinyl alcohol copolymer solution into contact with the steam in a countercurrent. The temperature inside the column was 130°C and the pressure inside the column was 0.3 MPa. The hydrated ethylene vinyl alcohol copolymer obtained by contacting it with steam in a countercurrent was withdrawn from the bottom of the column. The temperature of the obtained hydrated ethylene vinyl alcohol copolymer was 120°C and the water content was 52.4% by mass. The methanol content was 0.02% by mass. The hydrated ethylene vinyl alcohol copolymer was supplied at 42 kg / hr to a twin-screw extruder with a back slit and extruded under the following conditions from a die with a hole diameter of 3.0 mm and 8 holes attached to the tip of the extruder. 【0170】 (Twin-screw extruder specifications) L / D: 14 ​​Bore: 30 mm Screw: Full flight RPM: 300 rpm Cylinder temperature: 90°C Die temperature: 120°C 【0171】 The extruded molten material was cut with a hot cutter having two blades at a distance of 0.05 mm from the die to obtain a porous body of ethylene vinyl alcohol copolymer in the shape of a flattened spherical pellet. The flow rate of the cutter circulating water was 300 liters / minute, and the rotation speed of the cutter blades was 3000 rpm. At this time, the resin temperature (outlet) was 95°C, and the water content was 34% by mass. 【0172】 The porous ethylene vinyl alcohol copolymer obtained was washed with water at 50°C until the sodium acetate content was 0.002% by mass or less (sodium equivalent), and the washing water was filtered off to obtain a flattened spherical pellet-shaped porous ethylene vinyl alcohol copolymer (EVOH1). The obtained EVOH1 was a flattened spherical pellet with an average particle diameter of 3.2 mm. EVOH1 had pores ranging in diameter from 0.003 μm to 100 μm, with a median pore diameter of 0.11 μm. Table 1 shows the median pore diameter, pore surface area (specific surface area), and average particle diameter of the obtained EVOH1. 【0173】 <Production Example 2> A porous body of ethylene vinyl alcohol copolymer (EVOH2) in pellet form was obtained in the same manner as in Production Example 1, except that an ethylene vinyl alcohol copolymer with an ethylene content of 38 mol% was used. The obtained EVOH2 pellets were flattened spherical with an average particle diameter of 3.2 mm. The EVOH2 pellets had pores ranging in diameter from 0.003 μm to 100 μm, with a median pore diameter of 0.09 μm. Table 1 shows the median pore diameter, average particle diameter, and pore surface area (specific surface area) of the obtained EVOH2. 【0174】 <Production Example 3> A porous body of ethylene vinyl alcohol copolymer (EVOH3) in pellet form was obtained in the same manner as in Production Example 1, except that an ethylene vinyl alcohol copolymer with an ethylene content of 44 mol% was used. The obtained EVOH3 pellets were flattened spherical with an average particle diameter of 3.0 mm. The EVOH3 pellets had pores with diameters ranging from 0.03 μm to 100 μm, and the median diameter of the pores was 0.07 μm. Table 1 shows the median diameter of the pores, the average particle diameter, and the pore surface area (specific surface area) of the obtained EVOH3. 【0175】 <Production Example 4> A porous body of ethylene vinyl alcohol copolymer (EVOH4) in pellet form was obtained in the same manner as in Production Example 1, except that an ethylene vinyl alcohol copolymer with an ethylene content of 27 mol% was used. The obtained EVOH4 pellets were flattened spherical with an average particle diameter of 3.2 mm. The EVOH4 pellets had pores with diameters ranging from 0.03 μm to 100 μm, and the median diameter of the pores was 0.11 μm. Table 1 shows the median diameter of the pores, the average particle diameter, and the pore surface area (specific surface area) of the obtained EVOH4. 【0176】<Production Example 5> A porous body of ethylene vinyl alcohol copolymer (EVOH5) in pellet form was obtained in the same manner as in Production Example 1, except that ethylene vinyl alcohol copolymers with different MFRs and an ethylene content of 32 mol% were used. The obtained EVOH5 pellets were flattened spherical with an average particle diameter of 2.9 mm. The EVOH5 pellets had pores ranging in diameter from 0.03 μm to 100 μm, with a median pore diameter of 0.11 μm. Table 3 shows the median pore diameter, average particle diameter, and pore surface area (specific surface area) of the obtained EVOH5. <Production Example 6> The EVOH2 pellets obtained in Production Example 2 were classified using a stainless steel sieve with a mesh opening of 2.8 mm to obtain a porous body of ethylene vinyl alcohol copolymer (EVOH6) in pellet form. The obtained EVOH6 pellets were flattened spherical with an average particle diameter of 4.8 mm. The EVOH6 pellets had pores ranging in diameter from 0.003 μm to 100 μm, with a median pore diameter of 0.10 μm. Table 3 shows the median pore diameter, average particle diameter, and pore surface area (specific surface area) of the obtained EVOH6 pellets. 【0177】 <Manufacturing Example 7> Using "EVAL® E105B (manufactured by Kuraray Co., Ltd.)" as an ethylene vinyl alcohol copolymer with an ethylene content of 44 mol%, freeze-milling was performed using an ultracentrifuge ZM300 (manufactured by Verder Scientific Co., Ltd.) to obtain a non-porous ethylene vinyl alcohol copolymer (EVOH7). The obtained EVOH7 powder had an average particle size of 0.091 mm, and no pores were observed. The average particle size of the obtained EVOH7 and the specific surface area calculated from the average particle size are shown in Table 3. 【0178】 <Production Example 8> A porous body of ethylene vinyl alcohol copolymer (EVOH8) in pellet form was obtained in the same manner as in Production Example 1, except that the ethylene content was set to 15 mol%. The obtained EVOH8 pellets were flattened spherical with an average particle diameter of 3.2 mm. The EVOH8 pellets had pores ranging in diameter from 0.003 μm to 100 μm, with a median pore diameter of 0.05 μm. Table 3 shows the median pore diameter, average particle diameter, and pore surface area (specific surface area) of the obtained EVOH8. 【0179】<Example 1> As a raw material resin, 100 parts by mass of EVOH1 obtained in Production Example 1 was dispersed in 377 parts by mass of water, and 26 parts by mass of isobutyraldehyde (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The resulting dispersion was heated to 60°C under stirring. Stirring was continued for 6 hours to impregnate the ethylene vinyl alcohol copolymer with isobutyraldehyde. Then, at 60°C, 1.7 parts by mass of 20% hydrochloric acid (manufactured by Takasugi Pharmaceutical Co., Ltd.) was added to the dispersion as an acidic catalyst, and the acetalization reaction was carried out for 22 hours. The acetalized product produced by acetalization was in a solid state. That is, the acetalization reaction was a solid-liquid reaction. The concentration of the acidic catalyst after the acetalization reaction by solid-liquid reaction, i.e., the hydrochloric acid concentration, was determined by neutralization titration. The results are shown in Table 1. 【0180】 Subsequently, the obtained acetalized material was filtered off, and 500 parts by mass of deionized water was added to the acetalized material. The mixture was then stirred at 75°C for 6 hours to wash the acetalized material. After that, 2.0 parts by mass of 1 M sodium hydroxide (manufactured by Takasugi Pharmaceutical Co., Ltd.) was added to neutralize the mixture. To neutralize the solid interior of the acetalized material, the dispersion was stirred at 60°C for a further 8 hours. 【0181】 The neutralized acetal was collected by filtration, and 500 parts by mass of deionized water was added to the acetal. The mixture was stirred at 75°C for 4 hours to perform a second wash of the acetal. The wash water was filtered off, and vacuum drying was carried out at 60°C for 8 hours to obtain 113 parts by mass (100% yield) of pelletized acetal (A-1). The obtained acetal was a porous material having a pore structure similar to that of the raw material EVOH1. The measurement results for the obtained acetal are shown in Table 1. 【0182】 The acetalized material obtained above was melt-kneaded for 3 minutes at a chamber temperature of 200°C and a rotation speed of 100 rpm using a Laboplast Mill (Toyo Seiki Seisakusho Co., Ltd., "4M150"). The contents of the chamber were removed and cooled to obtain a molten mixture. The obtained molten mixture was heated at 210°C at a rate of 50 kgf / cm² using a release film (Upirex®-S (UBE Corporation)) with a maximum roughness height (Rz) of less than 100 nm. ２The material was compressed and molded at a pressure of 50 MPa for 5 minutes to obtain a sheet-like acetalized resin sheet with a thickness of 0.8 mm. The evaluation results are shown in Table 1. 【0183】 <Examples 2-3> Acetalized products (A-2 and A-3) were obtained in the same manner as in Example 1, except that the ethylene vinyl alcohol copolymer used was changed to EVOH2 and EVOH3, respectively, and the reaction conditions were changed as shown in Table 1. The obtained acetalized products were porous bodies having a pore structure similar to that of the ethylene vinyl alcohol copolymer used as the raw material. The measurement results for each of the obtained acetalized products are shown in Table 1. Using the obtained acetalized products, melt-kneaded products and resin sheets were obtained in the same manner as in Example 1. The evaluation results for each are shown in Table 1. 【0184】<Comparative Example 1> Following the method described in Example 16 of International Publication No. 2022 / 220085, an acetalized product (A-4) was obtained. Specifically, 100 parts by mass of EVOH4 obtained in Production Example 4 was dispersed in 377 parts by mass of water, and 23.3 parts by mass of isobutyraldehyde (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The resulting dispersion was heated to 60°C under stirring. Stirring was continued for 2 hours to impregnate the ethylene vinyl alcohol copolymer with isobutyraldehyde. Then, at 60°C, 10 parts by mass of 1 M hydrochloric acid (manufactured by Takasugi Pharmaceutical Co., Ltd.) was added to the dispersion, and the acetalization reaction was carried out for 2 hours. After that, 40 parts by mass of 1 M hydrochloric acid was added, and the acetalization reaction was carried out for a further 6 hours. Then, the acetalization reaction was stopped by neutralizing the dispersion with 75 parts by mass of 1 M sodium hydroxide. To neutralize the solid interior of the acetal, the dispersion was stirred at 60°C for a further 8 hours. The neutralized acetal was filtered off, and 500 parts by mass of deionized water was added to the acetal and stirred at 60°C for 6 hours to wash it. The acetal was filtered off again, and 500 parts by mass of deionized water was added to the acetal and stirred at 60°C for 6 hours to wash it a second time. The washing water was filtered off, and the acetal was vacuum dried at 60°C for 8 hours to obtain pelletized ethylene vinyl alcohol copolymer acetal. The acetal produced by acetalization was in a solid state. The obtained acetal was a porous material with a pore structure similar to that of EVOH4 used as a raw material. Using the synthesized ethylene vinyl alcohol copolymer acetal (A-4), a melt kneaded product and a resin sheet were obtained in the same manner as in Example 1. The evaluation results are shown in Table 1. 【0185】<Comparative Example 2> EVOH1 obtained in Production Example 1 was dispersed in 100 parts by mass and 377 parts by mass of water, and 26 parts by mass of isobutyraldehyde (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The resulting dispersion was heated to 60°C under stirring. Stirring was continued for 3.5 hours to impregnate the ethylene vinyl alcohol copolymer with isobutyraldehyde. Then, at 60°C, 10 parts by mass of 1 M hydrochloric acid (manufactured by Takasugi Pharmaceutical Co., Ltd.) was added to the dispersion, and an acetalization reaction was carried out for 2 hours. After that, 40 parts by mass of 1 M hydrochloric acid was added, and the acetalization reaction was carried out for a further 6 hours. The acetalized product produced by acetalization was in a solid state. The obtained acetalized product was a porous body having a pore structure similar to that of EVOH1 used as a raw material. The measurement results of the obtained acetalized product (A-5) are shown in Table 1. Using the obtained acetalized product, a molten compound and a resin sheet were obtained in the same manner as in Example 1. The results of each evaluation are shown in Table 1. 【0186】 <Comparative Example 3> An acetal (A-6) was obtained in the same manner as in Comparative Example 2, except that the ethylene vinyl alcohol copolymer used was changed to EVOH2 and the reaction conditions were changed as shown in Table 1. The obtained acetal was a porous body having a pore structure similar to that of EVOH2 used as a raw material. The measurement results for the obtained acetal are shown in Table 1. Using the obtained acetal, a melt-kneaded product and a resin sheet were obtained in the same manner as in Example 1. The evaluation results for each are shown in Table 1. 【0187】 <Comparative Example 4> Acetalized product (A-7) was obtained in the same manner as in Example 2, except that the reaction conditions were changed as shown in Table 1. The obtained acetalized product was a porous body having a pore structure similar to that of EVOH2 used as a raw material. The measurement results for each of the obtained acetalized products are shown in Table 1. Using the obtained acetalized products, a molten compound and a resin sheet were obtained in the same manner as in Example 1. The evaluation results for each are shown in Table 1. 【0188】<Comparative Example 5> EVOH3 obtained in Manufacturing Method 3 was dispersed in 100 parts by mass and 315 parts by mass of 1-propanol. The solution was heated to 60°C under stirring, then 40 parts by mass of 1 M hydrochloric acid was added, followed by 16.7 parts by mass of n-butyraldehyde, which was dispersed. The acetalization reaction was then carried out while maintaining the temperature at 60°C. As the reaction progressed, the chips dissolved and a homogeneous solution was obtained. After 36 hours from the start of the reaction, 6.4 parts by mass of sodium carbonate was added to stop the reaction. 500 parts by mass of 1-propanol was added to the reaction solution to homogenize it, and then 2000 parts by mass of water was added dropwise to precipitate the resin. The filtration and washing operations were repeated three times, and the acetalized product (A-8) was obtained by vacuum drying at 60°C for 8 hours. The measurement results of the obtained acetalized product are shown in Table 1. Using the obtained acetalized product, a molten compound and a resin sheet were obtained in the same manner as in Example 1. The results of each evaluation are shown in Table 1. 【0189】 <Comparative Example 6> The EVOH3 obtained in Manufacturing Method 3 was dispersed in 100 parts by mass, 120 parts by mass of water, and 195 parts by mass of 1-propanol. The temperature of the solution was raised to 60°C under stirring and dissolved until homogeneous. After dissolution, 40 parts by mass of 1 M hydrochloric acid was added, followed by 16.7 parts by mass of n-butyraldehyde, which was dispersed. The acetalization reaction was then carried out while maintaining the temperature at 60°C. After maintaining the temperature for 4 hours from the start of the reaction, 6.4 parts by mass of sodium carbonate was added to stop the reaction. 500 parts by mass of 1-propanol was added to the reaction solution to homogenize it, and then it was added dropwise to 2000 parts by mass of water to precipitate the resin. The filtration and washing operations were repeated three times, and the acetalized product (A-9) was obtained by vacuum drying at 60°C for 8 hours. The measurement results of the obtained acetalized product are shown in Table 1. Using the obtained acetalized product, a molten compound and a resin sheet were obtained in the same manner as in Example 1. The results of each evaluation are shown in Table 1. 【0190】 <Example 4> 100 parts by mass of the acetal compound (A-1) obtained in Example 1 was mixed with a polyoxyethylene alkyl ether (Dow Chemical Japan Ltd. "Targitol 15-S-5" (product name)) as a plasticizer, with an SP value of 9.5 (cal / cm³). ３ ) １／２20 parts by mass of ) and 0.15 parts by mass of Tinuvin 234 (manufactured by BASF Japan Ltd.) as an ultraviolet absorber were added to prepare a resin composition, and a resin sheet was obtained in the same manner as in Example 1. The obtained resin sheet was sandwiched between two 2.7 mm thick float glass sheets and placed in a vacuum laminator (1522N manufactured by Nisshinbo Mechatronics Inc.), and the inside of the vacuum laminator was reduced in pressure at 100°C for 1 minute. A temporary bond was obtained by pressing at 30 kPa for 5 minutes while maintaining the reduced pressure and temperature. The obtained temporary bond was placed in an autoclave and treated at 140°C and 1.2 MPa for 30 minutes to obtain laminated glass. 【0191】 <Examples 5-6> Resin compositions, resin sheets, and laminated glass were obtained in the same manner as in Example 4, except that the acetal compounds used were changed as shown in Table 2. 【0192】 <Comparative Examples 7-12> Resin compositions, resin sheets, and laminated glass were obtained in the same manner as in Example 4, except that the acetal compounds and / or plasticizers used were changed as shown in Table 2. Note that the plasticizer PPG#400 in Table 2 is polypropylene glycol with an average molecular weight of 400 (PPG#400 (trade name) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and its SP value is 10.1 (cal / cm³). ３ ) １／２ That is the case. 【0193】 <Examples 7-11> Acetalized products (A-10 to A-14) were obtained in the same manner as in Example 1, except that the ethylene vinyl alcohol copolymers used were changed to EVOH4, EVOH5, EVOH2, EVOH2, and EVOH6, respectively, and the reaction conditions were changed as shown in Table 3. The obtained acetalized products were porous bodies having a pore structure similar to that of the ethylene vinyl alcohol copolymers used as raw materials. The measurement results for each of the obtained acetalized products are shown in Table 3. Using the obtained acetalized products, melt-kneaded products and resin sheets were obtained in the same manner as in Example 1. The evaluation results for each are shown in Table 3. 【0194】<Example 12> Acetalized product (A-15) was obtained in the same manner as in Example 1, except that the ethylene vinyl alcohol copolymer used was changed to EVOH7 and the reaction conditions were changed as shown in Table 3. The obtained acetalized product was non-porous, similar to the ethylene vinyl alcohol copolymer used as the raw material. The measurement results for the obtained acetalized product are shown in Table 3. Using the obtained acetalized product, a molten kneaded product and a resin sheet were obtained in the same manner as in Example 1. The evaluation results for each product are shown in Table 3. 【0195】 <Comparative Examples 13-14> Acetalized products (A-16 and A-17) were obtained in the same manner as in Example 1, except that the ethylene vinyl alcohol copolymer used was changed to EVOH4 and EVOH2, respectively, and the reaction conditions were changed as shown in Table 3. The obtained acetalized products were porous bodies having a pore structure similar to that of the ethylene vinyl alcohol copolymer used as the raw material. The measurement results for each of the obtained acetalized products are shown in Table 3. Using the obtained acetalized products, melt-kneaded products and resin sheets were obtained in the same manner as in Example 1. The evaluation results for each are shown in Table 3. 【0196】<Comparative Example 15> The ethylene vinyl alcohol copolymer used was changed to EVOH8, and an acetal (A-18) was obtained following the method described in Example 1 of Patent Document 2011-57737. Specifically, 100 parts by mass of EVOH8 obtained in Production Example 8 was dissolved in 900 parts by mass of water to obtain an aqueous solution of ethylene vinyl alcohol copolymer with a concentration of 10% by weight. With this aqueous solution at 40°C, 32 parts by mass of 35% hydrochloric acid was added while stirring with an anchor-type stirring blade, followed by the dropwise addition of 64 parts by mass of n-butyraldehyde (manufactured by Mitsubishi Chemical Corporation). After confirming that the acetal of the ethylene vinyl alcohol copolymer had precipitated 30 minutes after the end of the dropwise addition, the temperature was raised to 50°C while adding another 64 parts by mass of 35% hydrochloric acid and the mixture was stirred for 4 hours to complete the reaction. The obtained dispersion was cooled, and the pH of the dispersion was neutralized to 7.5 with 30 parts by mass of aqueous sodium hydroxide solution. After filtration, it was washed with 2000 parts by mass of water and dried to obtain acetalized material (A-18). The measurement results of the obtained acetalized material are shown in Table 3. Using the obtained acetalized material, a molten compound and a resin sheet were obtained in the same manner as in Example 1. The evaluation results are shown in Table 3. 【0197】 <Examples 13-21> Resin compositions, resin sheets, and laminated glass were obtained in the same manner as in Example 4, except that the acetal compounds and / or plasticizers used were changed as shown in Table 4. Note that the plasticizer ethylene alkyl ether (Berol 260) in Table 4 is Berol 260 (trade name) manufactured by Noryon Co., Ltd., and its SP value is 9.8 (cal / cm³). ３ ) １／２ Furthermore, the plasticizer di-(2-butoxyethoxyethyl)-adipate ester (DBEEA) is manufactured by Sigma-Aldrich Co., Ltd., and its SP value is 9.3 (cal / cm³). ３ ) １／２ That is the case. 【0198】 <Comparative Examples 16-18> Resin compositions, resin sheets, and laminated glass were obtained in the same manner as in Example 4, except that the acetal compounds and / or plasticizers used were changed as shown in Table 4. The evaluation results for each are shown in Table 4. 【0199】 【0200】 As shown in Tables 1 and 3, Examples 1-3 and Examples 7-12 had lower YI and haze compared to Comparative Examples 1-4 and Comparative Examples 13 and 14, confirming that the resin sheets formed with the acetal derivative of the present invention exhibited superior transparency and hue, particularly in hue. Furthermore, Examples 1-3 and Examples 7-12 had higher storage modulus at 80°C and relaxation modulus at 50°C compared to Comparative Examples 5, 6, and 15, confirming that the resin sheets formed with the acetal derivative of the present invention exhibited superior self-supporting ability and creep resistance in high-temperature environments. In addition, Examples 1-3 and Examples 7-12 possessed sufficient penetration energy and were confirmed to have excellent penetration resistance. On the other hand, Comparative Examples 1-4 and 13 and 14 had high YI and poorer hue compared to Examples 1-3. Furthermore, Comparative Examples 5, 6, and 15 had low storage modulus at 80°C and relaxation modulus at 50°C, resulting in poor self-supporting ability and creep resistance in high-temperature environments. 【0201】 【0202】 As shown in Tables 2 and 4, Examples 4-6 and 13-21 showed lower YI and haze compared to Comparative Examples 7-10 and 16-18, confirming that the resin sheets and laminated glass formed with the compositions of the present invention exhibited superior hue and transparency. Furthermore, Examples 4-6 and 13-21 showed higher storage modulus at 80°C and relaxation modulus at 50°C compared to Comparative Examples 11, 12, and 16-18, confirming that the resin sheets formed with the compositions of the present invention exhibited superior self-supporting properties and creep resistance in high-temperature environments. In addition, Examples 4-6 and 13-21 were confirmed to have sufficient penetration energy and excellent penetration resistance. On the other hand, Comparative Examples 7-10 and 16-18 showed high YI and haze, and inferior hue and / or transparency compared to Examples 4-6. Furthermore, in Comparative Examples 11, 12, and 16-18, the storage modulus at 80°C and the relaxation modulus at 50°C were low, resulting in poor self-support and creep resistance in high-temperature environments. 【0203】 【0204】

Claims

1. An acetalized ethylene vinyl alcohol copolymer, comprising 0.1 to 80 mol% ethylene units, 0.1 to 94.9 mol% vinyl alcohol units, and 5 to 50 mol% acetal units, based on the total monomer units constituting the acetalized, and having a full width at half maximum (FWHM) W determined by reverse-phase partition gradient high-performance liquid chromatography analysis using a water-ethanol eluent in accordance with JIS K0124:2011. ０．５ｈ However, the acetal compounds have a ratio of 1.10 to 1.

35.

2. The acetalized product according to claim 1, wherein the melting peak temperature measured in accordance with JIS K7121:2012 is 105°C or higher.

3. The acetal compound according to claim 1, wherein the heat of fusion measured in accordance with JIS K7122:2012 is 5 to 100 mJ / mg.

4. The acetalized product according to claim 1, wherein the meso / racemo ratio of the acetal ring structure is less than 5.

5. The acetal compound according to claim 1, wherein the haze at a sheet thickness of 0.8 mm is less than 1%, as measured in accordance with JIS K7136:2000.

6. A composition comprising the acetal compound described in claim 1 and a plasticizer, wherein the content of the acetal compound is 70% by mass or more.

7. The composition according to claim 6, wherein the haze at a sheet thickness of 0.8 mm, as measured in accordance with JIS K7136:2000, is less than 1%.

8. A resin sheet comprising one or more layers containing the acetal compound described in claim 1 or the composition described in claim 6.

9. An interlayer for laminated glass comprising the resin sheet described in claim 8.

10. Laminated glass comprising the interlayer for laminated glass described in claim 9.

11. A method for producing an acetalized product of an ethylene vinyl alcohol copolymer according to any one of claims 1 to 5, comprising the steps of preparing a dispersion containing a solid ethylene vinyl alcohol copolymer and a dispersion medium, and an acetalization step of carrying out an acetalization reaction of the ethylene vinyl alcohol copolymer, wherein the acetalization reaction is carried out by a solid-liquid reaction in the presence of an acidic catalyst, and the concentration of the acidic catalyst after the acetalization reaction is 0.05 mol / L or less.

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