Acetate of ethylene vinyl alcohol copolymer, composition and barrier material comprising same

Abstract

The present invention relates to an acetalate of an ethylene-vinyl alcohol copolymer, the acetalate comprising 20-80 mol% of ethylene units and 4-76 mol% of vinyl alcohol units based on the total monomer units constituting the acetalate, the acetalate having a degree of acetalation of 3-80 mol%, and satisfies formula (1): 0.71 < = W0.05 h / 2f < = 1.09 (W0.05 h / 2f represents a symmetry coefficient determined by reversed phase partition gradient high performance liquid chromatography based on a water-ethanol eluent in accordance with JIS K 0124: 2011) and formula (2): 1.20 < = Tm / Tg < = 1.35 (Tm and Tg respectively represent a melting peak temperature (K) and an intermediate point glass transition temperature (K) measured in accordance with JIS K7121: 2012), and the oxygen permeation rate at 20 DEG C and 65% RH is 150 cc.20 [mu] m / m2. Day. Atm or less.

Description

Technical Field

[0001] This patent application claims Paris Convention priority based on Japanese Patent Application No. 2022-166255 (filing date: October 17, 2022), which is incorporated herein in its entirety by reference.

[0002] The present invention relates to an acetalized product of an ethylene vinyl alcohol copolymer and a method for producing the same, a composition containing the acetalized product, a resin film comprising a layer containing the acetalized product, a resin film comprising a layer containing the composition, a barrier material comprising the resin film, and a molded product comprising the resin film. Background Art

[0003] Ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as EVOH) has excellent transparency and gas barrier properties, but has the disadvantage of lacking stretchability and flexibility. In order to improve this disadvantage, a method of blending a soft resin such as ethylene-vinyl acetate copolymer or ethylene-propylene copolymer into EVOH is known. However, this method has the disadvantage of significantly reducing heat resistance and transparency.

[0004] In addition, Patent Document 1 discloses an ethylene-vinyl alcohol copolymer modified with a monovalent epoxy compound having a molecular weight of 500 or less (e.g., 1,2-butylene oxide or propylene oxide), and states that the modified ethylene-vinyl alcohol copolymer has excellent barrier properties, transparency, stretchability, flexibility, and bending resistance. Patent Document 2 discloses an ethylene-vinyl alcohol-vinyl acetal copolymer having excellent combined properties of hot water resistance and oxygen barrier properties, and a packaging material formed of an olefin-vinyl alcohol-vinyl acetal copolymer and having excellent combined properties of hot water resistance and oxygen barrier properties.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2006-233222

[0008] Patent Document 2: Japanese Patent Publication No. 55-46642 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] However, according to the research conducted by the present inventors, it has been found that the barrier properties, transparency, stretchability, flexibility and heat resistance of the films made of copolymers in the above-mentioned prior art are not always sufficient and there is still room for improvement.

[0011] Therefore, an object of the present invention is to provide an acetalized product of an ethylene vinyl alcohol copolymer capable of forming a resin film having excellent barrier properties, transparency, stretchability, flexibility, and heat resistance.

[0012] Solutions for solving problems

[0013] The present inventors have conducted intensive studies to solve the above-mentioned problems and have achieved the present invention. That is, the present invention includes the following preferred aspects.

[0014] [1] An acetalized product of an ethylene vinyl alcohol copolymer, comprising 20 to 80 mol% of ethylene units and 4 to 76 mol% of vinyl alcohol units based on all monomer units constituting the acetalized product,

[0015] The acetalization degree of the acetalized product is 3 to 80 mol %, and satisfies formula (1) and formula (2):

[0016] 0.71≤W 0.05h / 2f≤1.09 (1)

[0017] In formula (1), W 0.05h / 2f represents the symmetry coefficient determined by reverse phase partition gradient HPLC analysis using a water-ethanol eluent in accordance with JIS K 0124:2011]

[0018] 1.20≤Tm / Tg≤1.35 (2)

[0019] [In formula (2), Tm and Tg represent the melting peak temperature (absolute temperature) and the midpoint glass transition temperature (absolute temperature) measured in accordance with JIS K7121:2012, respectively]

[0020] The oxygen permeability of the acetal compound at 20°C and 65% RH is 150cc·20μm / m 2 ·day·atm or less.

[0021] [2] The acetal compound according to [1] above, which satisfies the formula (3):

[0022] {ΔH (J / g)×Tm (absolute temperature)×amount of vinyl alcohol units (mol%) / 100} / (oxygen permeation rate at 20°C and 65%RH)≥30 (3).

[0023] [3] The acetalized product according to [1] or [2] above, wherein the degree of acetalization is 40 mol% or less.

[0024] [4] The acetal compound according to any one of [1] to [3] above, which has a melting peak temperature Tm measured in accordance with JIS K7121:2012 of 136° C. or higher.

[0025] [5] The acetal compound according to any one of [1] to [4], which has a tensile modulus of elasticity at 23°C and 50% RH of 2000 MPa or less.

[0026] [6] A composition comprising:

[0027] (A) the acetal compound described in any one of [1] to [5] above; and

[0028] (B) one or more resins selected from the group consisting of (B-1) acetalized products of ethylene vinyl alcohol copolymers other than (A), (B-2) ethylene vinyl alcohol copolymers, and (B-3) resins other than (B-1) and (B-2).

[0029] [7] The method for producing an acetal compound according to any one of [1] to [5], comprising:

[0030] (i) preparing a dispersion liquid containing an ethylene vinyl alcohol copolymer, an aldehyde, and a solvent, and allowing at least a portion of the aldehyde to permeate the ethylene vinyl alcohol copolymer; and

[0031] (ii) after step (i), a step of adding a catalyst to the dispersion to acetalize the ethylene vinyl alcohol copolymer,

[0032] The acetalization is performed by a solid-liquid reaction.

[0033] [8] A resin film comprising one or more layers containing the acetalized product according to any one of [1] to [5] above.

[0034] [9] A resin film comprising one or more layers containing the composition according to [6].

[0035]

[10] The resin film according to [8] above, further comprising one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes.

[0036]

[11] The resin film according to [9] above, further comprising one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes.

[0037]

[12] A barrier material comprising the resin film according to any one of [8] to

[11] above.

[0038]

[13] A molded article comprising the resin film according to any one of [8] to

[11] above.

[0039] Effects of the Invention

[0040] According to the present invention, there is provided an acetalized product of an ethylene vinyl alcohol copolymer capable of forming a resin film having excellent barrier properties, transparency, stretchability, flexibility and heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is an example of the measurement result of high performance liquid chromatography (HPLC) for explaining the symmetry coefficient. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the scope of the present invention is not limited to the embodiments described herein, and various changes can be made within the scope of the gist of the present invention. In addition, when multiple upper and lower limits are recorded about specific parameters, any upper and lower limits among these upper and lower limits can be combined to form a suitable numerical range.

[0043] [Acetalized product of ethylene vinyl alcohol copolymer]

[0044] The acetalized product of the ethylene vinyl alcohol copolymer of the present invention (hereinafter also referred to as "acetalized product") satisfies the following formulas (1) and (2), and has an oxygen permeability of 150 cc·20 μm / m at 20°C and 65% RH. 2 ·day·atm or less.

[0045] 0.71≤W 0.05h / 2f≤1.09 (1)

[0046] In formula (1), W 0.05h / 2f represents the symmetry coefficient determined by reverse phase partition gradient HPLC analysis using a water-ethanol eluent in accordance with JIS K 0124:2011]

[0047] 1.20≤Tm / Tg≤1.35 (2)

[0048] [In formula (2), Tm and Tg represent the melting peak temperature (absolute temperature) and the midpoint glass transition temperature (absolute temperature) measured in accordance with JIS K7121:2012, respectively]

[0049] The present inventors prepared a product that satisfies both the above formula (1) and the formula (2) and has an oxygen permeability of 150 cc·20 μm / m at 20°C and 65% RH. 2 ·day·atm or less, it was surprisingly found that a resin film (resin sheet) comprising the acetalized product had excellent barrier properties, transparency, stretchability, flexibility and heat resistance.

[0050] The acetal compound of the present invention has a symmetry coefficient W calculated according to JIS K 0124:2011. 0.05h / 2f is 0.71 to 1.09, so the obtained resin film is likely to have high transparency. It can be considered that this is because: by setting the symmetry coefficient within the above range, a moderate acetalization degree distribution is given to the acetalized product. On the other hand, if the symmetry coefficient is outside the above range, there is a tendency that the deviation of the acetalization degree of the obtained acetalized product becomes larger and the transparency decreases. In addition, if the symmetry coefficient exceeds the above upper limit, the proportion of the acetalized product with a high acetalization degree (high acetalization degree component) in the obtained acetalized product increases, and the transparency is likely to decrease. If the symmetry coefficient is less than the above lower limit, the proportion of the acetalized product with a low acetalization degree (low acetalization degree component) in the obtained acetalized product increases, and the transparency and formability are likely to decrease.

[0051] From the viewpoint of easily improving transparency and formability, the aforementioned symmetry coefficient is preferably 1.05 or less, more preferably 1.00 or less, further preferably 0.95 or less, further preferably 0.92 or less, and particularly preferably 0.90 or less. In addition, from the viewpoint of easily improving transparency and formability, the aforementioned symmetry coefficient is preferably 0.73 or more, more preferably 0.75 or more, further preferably 0.77 or more, further preferably 0.79 or more, and particularly preferably 0.80 or more. Here, the symmetry coefficient is a coefficient indicating the degree of symmetry of the measured peak obtained using high performance liquid chromatography, and the closer the symmetry coefficient is to 1.0, the higher the symmetry of the peak.

[0052] The aforementioned symmetry coefficient W 0.05h / 2f can be determined by performing reverse phase partition gradient HPLC analysis using a water-ethanol eluent in accordance with JIS K 0124:2011. 0.05h " represents the peak width at a height of 1 / 20 of the peak height from the baseline of the measured peak obtained by HPLC analysis (peak 5% height position), and "f" represents the distance on the rising side of the peak when the peak width at the peak 5% height position is divided into two parts by a vertical line including the peak apex. Specifically, in the example of the measurement result of high performance liquid chromatography (HPLC), Figure 1 Among the peaks measured, “W 0.05h "express Figure 1 The peak width W shown in 0.05h , "f" means Figure 1 The distance f between ab shown in FIG. Figure 1 In the figure, a is the starting point at the 5% height position of the peak, and b is the intersection of the horizontal line including the peak starting point a and the vertical line including the peak apex. Figure 1 In the figure, the dotted line parallel to the horizontal axis represents the baseline.

[0053] The above-mentioned HPLC analysis can generally be performed under the following measurement conditions.

[0054] Sample concentration: 1.5mg / 1g

[0055] Sample solvent: ethanol (99.5%) / ion exchange water = 9 / 1 wt% mixed solvent

[0056] Injection volume: 20 μL

[0057] Detector: Varian 380-LC, EVAP 80℃ (front stage heating), NEB 50℃ (second stage heating), Gas 1.5 (SLM), data reading interval: 1000ms, filter: 1μm

[0058] ODS silica gel column: "Shimpack G-ODS (octadecyl-modified spherical fully porous silica gel, inner diameter 4 mm × length 10 mm, particle size: 5 μm)" manufactured by Shimadzu Corporation

[0059] Column temperature: 45°C

[0060] Liquid delivery flow rate: total flow rate is 0.4mL / min

[0061] In addition, the HPLC analysis of the present invention can be performed according to the following steps. Liquids of different polarities are used as mobile phases. Water is used as mobile phase A, and ethanol (99.5%) is used as mobile phase B. Before the sample is injected, the column of the HPLC system is filled with a mixed solvent of mobile phase A / mobile phase B at a volume ratio of 95 / 5. The sample is injected in this state. And the solvent is circulated under the following conditions.

[0062] 0~5 minutes (B concentration: 5% constant)

[0063] 5 to 25 minutes (B concentration: 5 to 100%)

[0064] 25-30 minutes (B concentration; 100% constant)

[0065] 30-31 minutes (B concentration: 100-5%)

[0066] 31~55 minutes (B concentration: _5% constant)

[0067] The symmetry coefficient can be adjusted by appropriately adjusting the distribution of the degree of acetalization in the acetalized product and / or the production conditions of the acetalized product, etc. For example, the symmetry coefficient can be adjusted to the above range by selecting the production method of the acetalized product of the ethylene vinyl alcohol copolymer described later, especially the acetalization method described as a preferred embodiment in the description described later, etc.

[0068] The ratio Tm / Tg of the melting peak temperature (absolute temperature) and the midpoint glass transition temperature (absolute temperature) measured according to JIS K7121:2012 of the acetal compound of the present invention is 1.20 to 1.35, so the transparency of the obtained resin film can be maintained and the flexibility and heat resistance can be ensured. It can be considered that this is because: generally, there is a tendency that the higher the crystallinity, the higher the heat resistance, but the lower the flexibility and transparency. By setting the aforementioned Tm / Tg of the acetal compound to the above range, the acetal compound is given appropriate crystallinity that can take into account transparency, flexibility and heat resistance. On the other hand, if Tm / Tg (K / K) exceeds the above upper limit, the transparency is easily reduced, and if it is less than the above lower limit, the heat resistance is easily reduced.

[0069] From the viewpoint of easily improving transparency, the aforementioned Tm / Tg (K / K) is preferably 1.34 or less, more preferably 1.33 or less, and further preferably 1.32 or less. In addition, from the viewpoint of easily improving heat resistance, Tm / Tg (K / K) is preferably 1.22 or more, and more preferably 1.25 or more. The aforementioned Tm / Tg (K / K) can be obtained by using a differential scanning calorimeter (DSC) and measuring the melting peak temperature (absolute temperature) and the midpoint glass transition temperature (absolute temperature) in accordance with JIS K7121:2012. In addition, it can be obtained by measuring the melting peak temperature Tm (°C) and the midpoint glass transition temperature Tg (°C), and converting these values ​​into absolute temperature (K). For example, it can be obtained by the method described in the examples.

[0070] The melting peak temperature Tm (°C) of the acetal compound of the present invention measured in accordance with JIS K7121:2012 is preferably 136°C or higher, more preferably 138°C or higher, further preferably 140°C or higher, further preferably 142°C or higher, particularly preferably 145°C or higher, and is preferably 180°C or lower, more preferably 175°C or lower, further preferably 170°C or lower, further preferably 165°C or lower. When the melting peak temperature Tm is at least the above lower limit, heat resistance such as retort resistance is easily improved, and when it is at most the above upper limit, transparency and moldability are easily improved.

[0071] The midpoint glass transition temperature Tg (°C) of the acetal compound of the present invention measured in accordance with JIS K7121:2012 is preferably 20°C or higher, more preferably 30°C or higher, and even more preferably 40°C or higher, and is preferably 80°C or lower, more preferably 60°C or lower, and even more preferably 50°C or lower. When the midpoint glass transition temperature Tg is at least the above lower limit, the moldability (for example, film forming property) is easily improved, and when it is at most the above upper limit, the flexibility of the obtained resin film is easily improved.

[0072] The Tm / Tg(K / K) can be adjusted by appropriately adjusting the distribution of the degree of acetalization in the acetalized product and / or the production conditions of the acetalized product, etc. For example, the Tm / Tg(K / K) can be adjusted to be within the above range by selecting a production method of the acetalized product of the ethylene vinyl alcohol copolymer described later, particularly an acetalization method described as a preferred embodiment in the description described later, etc.

[0073] The acetal compound of the present invention has an ethylene unit content of 20 to 80 mol% relative to all monomer units constituting the acetal compound. When the ethylene unit content is within the above range, the flexibility and barrier properties of the resulting resin film and the molding processability of the acetal compound are easily improved.

[0074] From the viewpoint of easily improving the flexibility, barrier properties and transparency of the obtained resin film, and the molding processability of the acetal product, the content of the aforementioned ethylene unit is preferably 25 mol% or more, more preferably 27 mol% or more, further preferably 30 mol% or more, and further preferably 32 mol% or more. In addition, from the viewpoint of easily improving the heat resistance, it is preferably 60 mol% or less, more preferably 55 mol% or less, further preferably 50 mol% or less, further preferably 48 mol% or less, particularly preferably 46 mol% or less, and more particularly preferably 44 mol% or less.

[0075] The content of the vinyl alcohol unit in the acetalized product of the present invention is 4 to 76 mol% based on the total monomer units constituting the acetalized product. When the content of the vinyl alcohol unit is within the above range, the transparency and barrier properties of the obtained resin film are easily improved.

[0076] From the viewpoint of easily improving the barrier properties, the content of the vinyl alcohol unit is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 25 mol% or more, further preferably 30 mol% or more, particularly preferably 33 mol% or more, further preferably 36 mol% or more, further particularly preferably 38 mol% or more, further particularly preferably 40 mol% or more, and from the viewpoint of easily improving the transparency of the obtained acetalized product, it is preferably 75 mol% or less, more preferably 70 mol% or less, further preferably 65 mol% or less, particularly preferably 60 mol% or less, further particularly preferably 58 mol% or less.

[0077] The content of the acetal unit (acetalized vinyl alcohol unit) in the acetal of the present invention is preferably 1 mol% or more, more preferably 1.5 mol% or more, further preferably 2.5 mol% or more, further preferably 3 mol% or more, particularly preferably 4 mol% or more, further preferably 5 mol% or more, further preferably 7 mol% or more, based on all monomer units constituting the acetal, from the viewpoint of easily suppressing the crystallinity of the acetal and easily improving the flexibility and transparency. Furthermore, from the viewpoint of easily improving the heat resistance and barrier properties (gas barrier properties), it is preferably 70 mol% or less, more preferably 60 mol% or less, further preferably 50 mol% or less, further preferably 40 mol% or less, particularly preferably 30 mol% or less, further preferably 25 mol% or less, further preferably 20 mol% or less.

[0078] The acetal compound of the present invention may contain vinyl ester units such as vinyl acetate units. From the viewpoint of thermal decomposition resistance, the content of the vinyl ester units is preferably 0 to 5 mol %, more preferably 0 to 2 mol %, and even more preferably 0 to 1 mol %.

[0079] The acetal compound of the present invention may further contain other monomer units in addition to the ethylene unit, vinyl alcohol unit and acetal unit, and the vinyl ester unit contained as required, within the scope that does not impair the effect of the present invention. As other monomer units, for example, α-olefins such as propylene, isobutylene, α-octene, and α-dodecene; unsaturated acids such as acrylic acid, methacrylic acid, methyl methacrylate, crotonic acid, maleic acid, and itaconic acid, or anhydrides, salts, or monoalkyl esters or dialkyl esters thereof; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methylallyl sulfonic acid, or salts thereof; alkyl vinyl ethers, vinyl ketones, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, etc. When the ethylene vinyl alcohol copolymer contains other monomer units, the content thereof is preferably 15 mol% or less, and more preferably 10 mol% or less.

[0080] The content of each unit in the acetal compound can be determined by NMR measurement, for example, by the method described in Examples.

[0081] The acetalization degree of the acetalized product is 3 to 80 mol%. If the acetalization degree is within the above range, the transparency, flexibility, heat resistance and barrier properties of the obtained resin film can be easily improved. From the viewpoint of easily suppressing the crystallinity of the acetalized product to a low level and easily improving transparency and flexibility, the acetalization degree is preferably 4 mol% or more, more preferably 5 mol% or more, further preferably 7 mol% or more, and further preferably 10 mol% or more. In addition, from the viewpoint of easily improving heat resistance and barrier properties, it is preferably 70 mol% or less, more preferably 62 mol% or less, further preferably 60 mol% or less, further preferably 50 mol% or less, particularly preferably 40 mol% or less, and further particularly preferably 35 mol% or less (for example, 30 mol% or less, 28 mol% or less, 26 mol% or less, 24 mol% or less, 22 mol% or less, less than 22 mol%, 20 mol% or less, 18 mol% or less, 16 mol% or less, and less than 16 mol%).

[0082] The degree of acetalization in the present invention refers to the ratio of the acetal unit to the total content of the acetal unit, vinyl alcohol unit, and vinyl ester unit such as vinyl acetate unit in the acetalized product. Specifically, when the content of the acetal unit is k, the content of the vinyl alcohol unit is l, and the content of the vinyl ester unit is m, the degree of acetalization in the present invention can be calculated by the following formula:

[0083] Acetalization degree (mol %)={k / (k+l+m)}×100.

[0084] The oxygen permeability rate (hereinafter also referred to as "OTR") of the acetal compound at 20°C and 65% RH is 150cc·20μm / m 2 ·day·atm or less. The above oxygen permeability rate is 150cc·20μm / m 2 ·day·atm or less indicates that the obtained resin film has high barrier properties to gases (especially oxygen). The above oxygen permeation rate is preferably 120cc·20μm / m 2 ·day·atm or less, more preferably 100cc·20μm / m 2 ·day·atm or less, more preferably 75cc·20μm / m 2 ·day·atm or less, more preferably 50cc·20μm / m 2 ·day·atm or less, particularly preferably 40cc·20μm / m 2 ·day·atm or less, more preferably 35cc·20μm / m 2 ·day·atm or less, more preferably 30cc·20μm / m 2The lower limit of the oxygen permeation rate is not particularly limited, and may be, for example, 0 cc·20 μm / m 2 ·day·atm or more.

[0085] The oxygen permeation rate at 20°C and 65% RH can be adjusted by appropriately adjusting the production conditions of the acetalized product, etc. For example, the oxygen permeation rate can be adjusted to be below the upper limit by selecting the production method of the acetalized product of the ethylene vinyl alcohol copolymer described later, especially the acetalization method described as a preferred embodiment in the description described later.

[0086] The oxygen permeation rate at 20° C. and 65% RH can be measured using an oxygen permeation measuring device, and can be measured by, for example, the method described in the examples described later.

[0087] In one embodiment of the present invention, the acetal compound of the present invention preferably satisfies the following formula (3) from the viewpoint of easily improving the properties of the obtained resin film, especially the heat resistance and barrier properties:

[0088] {ΔH (J / g) × Tm (absolute temperature) × vinyl alcohol unit amount (mol%) / 100} / OTR (cc·20μm / m 2 ·day·atm)≥30 (3).

[0089] In formula (3), ΔH is the crystal melting heat of the acetal compound measured in accordance with JIS K7121: 2012. More specifically, it represents the crystal melting heat measured by using DSC, heating from 25°C to 140°C at a heating rate of 10°C / min, maintaining at 140°C for 30 minutes, cooling from 140°C to -30°C at a cooling rate of 4°C / min, and heating from -30°C to 200°C again at a heating rate of 10°C / min.

[0090] The vinyl alcohol unit amount can be determined by NMR measurement, for example, by the method described in Examples.

[0091] From the viewpoint of making it easier to improve the properties of the obtained resin film, the value of {ΔH×Tm×amount of vinyl alcohol units / 100} / OTR is preferably 50 or more, more preferably 70 or more, and even more preferably 100 or more (for example, 150 or more, 250 or more). The reason why the value of {ΔH×Tm×amount of vinyl alcohol units / 100} / OTR is easier to improve the properties of the obtained resin film, especially the heat resistance and barrier properties, is not yet clear and is not limited to the following reasons, but it is considered that this is because the acetal compound has a suitable crystal structure to achieve heat resistance and barrier properties. The upper limit of {ΔH×Tm×amount of vinyl alcohol units / 100} / OTR is not particularly limited, and is usually 10,000 or less.

[0092] The value of {ΔH×Tm×amount of vinyl alcohol units / 100} / OTR can be adjusted by appropriately adjusting the conditions for producing the acetalized product, etc. For example, the value of {ΔH×Tm×amount of vinyl alcohol units / 100} / OTR can be adjusted to be above the lower limit by selecting the method for producing the acetalized product of the ethylene vinyl alcohol copolymer described later, especially the acetalization method described as a preferred embodiment in the description described later (especially the acetalization method using the preferred specific surface area and / or the preferred average particle size and / or the preferred aldehyde impregnation time and / or the preferred acetalization reaction time and / or the preferred acetalization catalyst concentration of the raw material EVOH).

[0093] The tensile modulus of the acetalized product in the tensile strength and elongation measurement at 23°C and 50%RH is preferably 2000 MPa or less, more preferably 1800 MPa or less, and further preferably 1600 MPa or less. The lower limit of the tensile modulus is not particularly limited, but from the viewpoint of the handleability as a film, it is preferably 10 MPa or more, more preferably 100 MPa or more, further preferably 300 MPa or more, further preferably 500 MPa or more, particularly preferably 650 MPa or more, and further preferably 800 MPa or more.

[0094] The tensile elongation at break of the acetalized product in the tensile strength and elongation measurement at 23°C and 50%RH is preferably 150% or more, more preferably 200% or more, further preferably 250% or more, and particularly preferably 300% or more. The upper limit of the tensile elongation at break is not particularly limited, but is usually 1000% or less.

[0095] By using the acetal compound, a soft film or a molded product can be obtained, and when these are stretched or thermoformed, secondary processing can be performed well.

[0096] The tensile elastic modulus and the tensile elongation at break can be measured by the method described in the examples described later.

[0097] The tensile modulus and tensile elongation at break can be adjusted by appropriately adjusting the production conditions of the acetalized product, etc. For example, with respect to the tensile modulus and tensile elongation at break, the tensile modulus can be adjusted to be below the upper limit, and the tensile elongation at break can be adjusted to be above the lower limit, by selecting the production method of the acetalized product of the ethylene vinyl alcohol copolymer described later, especially the acetalization method described as a preferred embodiment in the description described later.

[0098] In one embodiment of the present invention, from the viewpoint of easily suppressing the degradation of the acetalized product due to heat during the molding process, the melt flow rate (MFR) of the acetalized product measured under the conditions of 190° C. and 2.16 kg in accordance with JIS K7210:2014 is preferably 1 to 30 g / 10 min, more preferably 1.5 to 20 g / 10 min, further preferably 2 to 10 g / 10 min, and further preferably 2.5 to 9 g / 10 min.

[0099] As described above, the acetal compound of the present invention exhibits a low oxygen permeation rate, a low tensile elastic modulus, a high tensile elongation at break, and a high melting peak temperature. In addition, the resin film obtained from the acetal compound of the present invention exhibits the same values ​​of haze and stretchability as the resin film of the present invention described in the section [resin film, barrier material, molded article] described later. Therefore, the acetal compound of the present invention can form a resin film having excellent barrier properties, transparency, stretchability, flexibility, and heat resistance.

[0100] [Method for producing acetalized product of ethylene vinyl alcohol copolymer]

[0101] The method for producing the acetal compound of the present invention is not particularly limited, and the acetal compound can be produced, for example, by the following method, which comprises:

[0102] (i) preparing a dispersion liquid containing an ethylene vinyl alcohol copolymer, an aldehyde, and a solvent, and allowing at least a portion of the aldehyde to permeate the ethylene vinyl alcohol copolymer; and

[0103] (ii) after step (i), a step of adding a catalyst to the dispersion to acetalize the ethylene vinyl alcohol copolymer,

[0104] The acetalization is performed by a solid-liquid reaction.

[0105] <Step (i)>

[0106] Step (i) is a step of preparing a dispersion containing an ethylene vinyl alcohol copolymer, an aldehyde and a solvent (hereinafter also referred to as an "EVOH dispersion"), and impregnating at least a portion of the ethylene vinyl alcohol copolymer with the aldehyde.

[0107] By mixing the ethylene vinyl alcohol copolymer and the aldehyde in a dispersion and bringing them into sufficient contact, at least a portion of the aldehyde can be impregnated into the ethylene vinyl alcohol copolymer.

[0108] In the method of the present invention, the EVOH contained in the EVOH dispersion may be a porous body or a non-porous body.

[0109] When a porous body of ethylene vinyl alcohol copolymer (hereinafter also referred to as "EVOH porous body" or simply "porous body") is used as a raw material, it is easy to uniformly acetalize EVOH and to adjust the symmetry coefficient of the obtained acetalized product to the above range. Therefore, even if solid EVOH is acetalized by a non-uniform method, intermolecular crosslinking of EVOH is not likely to occur, and an acetalized product with excellent transparency can be obtained. This is considered to be because: by using an EVOH porous body, when at least a portion of the aldehyde described later is impregnated into EVOH, the aldehyde as an acetalizing agent not only impregnates into the solid surface of EVOH but also impregnates into the solid interior of EVOH through the pores, thereby enabling EVOH to be uniformly acetalized. As a result, the difference in the degree of acetalization between the solid surface and the solid interior of the acetalized product obtained by acetalization becomes small, and an acetalized product with a narrow distribution of the degree of acetalization is obtained.

[0110] In the present invention, the EVOH porous body is preferably EVOH having a plurality of pores, and a part or all of the pores preferably have openings on the surface of the porous body.

[0111] In one embodiment of the present invention, from the viewpoint of uniformly acetalizing EVOH and easily improving the transparency of the obtained acetalized EVOH, the median particle size of the pores in the aforementioned EVOH porous body is preferably 0.005 μm or more, more preferably 0.01 μm or more, and further preferably 0.02 μm or more. In addition, since the porous body is easy to maintain strength, the porous body is not easy to collapse and become powdery in the production process of the acetalized EVOH, and as a result, the production line is not easy to be blocked, and the acetalized product is easy to be efficiently produced. From the above viewpoint, the aforementioned median particle size is preferably 1 μm or less, more preferably 0.5 μm or less, further preferably 0.2 μm or less, further preferably less than 0.2 μm, particularly preferably 0.18 μm or less, particularly preferably 0.15 μm or less, and particularly preferably 0.12 μm or less. The median diameter of pores refers to the median diameter (d50) of all pores in the Log differential pore volume distribution with respect to the pore diameter range of 0.005 to 100 μm. It should be noted that the pore diameter used as a reference is set within the range of 0.005 to 100 μm because the pore distribution with a pore diameter greater than 100 μm is mainly the gaps between particles, and the pore distribution with a pore diameter less than the lower limit of the measurement, i.e., 0.005 μm, includes pseudo pores caused by compression, etc.

[0112] The median particle size of the pores of the porous body can be adjusted according to the manufacturing conditions of the porous body. For example, when an EVOH porous body is manufactured by preparing a composition containing EVOH and at least one solvent selected from water and alcohol, and extruding the composition into a coagulation liquid in the form of strands to coagulate it, and cutting the obtained strand-shaped coagulated material, the median particle size of the porous body can be adjusted according to the type and content of the solvent contained in the composition, the linear speed when extruding the composition, the extrusion temperature, the cooling rate, etc.

[0113] The median diameter of these pores can be measured by a pore distribution measuring device, for example, by the method described in Examples.

[0114] In one embodiment of the present invention, from the viewpoint of easily improving the transparency of the acetalized product of EVOH, the pore surface area (specific surface area) of the EVOH porous body within the range of 0.005 to 100 μm measured by mercury intrusion porosimetry is preferably 25 m 2 / g or more, more preferably 30m 2 In addition, from the viewpoint of easily suppressing the adhesion of EVOH porous bodies during high-temperature washing in the production process of the EVOH porous body, the pore surface area of ​​the EVOH porous body is preferably 45 m 2 / g or less, more preferably 41m 2 / g or less, more preferably 39m 2 / g or less.

[0115] The surface area of ​​pores within 0.005 to 100 μm of the EVOH porous body can be adjusted by the manufacturing conditions of the porous body. For example, in the same way as the method for adjusting the median particle size of the pores of the porous body, it can be adjusted by the type and content of the solvent contained in the aforementioned composition, the linear speed when the aforementioned composition is extruded into the coagulation liquid, the extrusion temperature, the cooling rate, etc. In addition, the aforementioned pore surface area of ​​the EVOH porous body can be measured using a pore distribution measuring device.

[0116] In one embodiment of the present invention, from the viewpoint of uniformly acetalizing EVOH and easily improving the transparency of the obtained acetalized EVOH, the pore volume of the EVOH porous body is preferably 0.1 mL / g or more, more preferably 0.2 mL / g or more, and further preferably 0.25 mL / g or more. In addition, from the viewpoint of easy handling, the pore volume is preferably 1.0 mL / g or less, more preferably 0.5 mL / g or less, and further preferably 0.3 mL / g or less.

[0117] The pore volume of the EVOH porous body can be adjusted by the manufacturing conditions of the porous body. For example, similar to the method for adjusting the median particle size of the pores of the porous body, it can be adjusted by the type and content of the solvent contained in the aforementioned composition, the linear speed when the aforementioned composition is extruded into the solidification liquid, the extrusion temperature, and the cooling rate when it is solidified. In addition, the pore volume of the porous body can be measured using a pore distribution measuring device.

[0118] In one embodiment of the present invention, from the viewpoint of handling, the average particle size of the EVOH porous body is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. In addition, from the viewpoint of uniformly acetalizing EVOH and easily improving the transparency of the acetalized product obtained thereby, the average particle size is preferably 10 mm or less, more preferably 7 mm or less, and further preferably 5 mm or less. The average particle size can be measured by the method described in the examples, for example.

[0119] The shape of the EVOH porous body is not particularly limited, and examples thereof include powder, granular, flake, bead, irregular shapes, etc. Among these, the porous body is preferably in a powder or granular form, and more preferably in a granular form. It should be noted that in the present invention, the granular porous body refers to a solid porous body with a substantially constant size such as a sphere, a cylinder, an elliptical cylinder, a polygonal column, and the like, and the cross section thereof may be circular, elliptical, polygonal, etc.

[0120] When the EVOH porous body in the present invention is in the form of pellets, the pellet-shaped porous body can be produced by the following methods as described below: a method in which the ethylene vinyl alcohol copolymer composition is extruded into a coagulation liquid, coagulated in the form of strands, and then the obtained strand-shaped coagulated material is cut into a specified length by a strand cutter; or a method in which the ethylene vinyl alcohol copolymer composition is directly cut in a molten state, etc.

[0121] As ethylene vinyl alcohol copolymer, for example, copolymers obtained by copolymerizing ethylene and vinyl ester monomers and saponifying the obtained copolymer can be listed. In one embodiment of the present invention, the ethylene content of the ethylene vinyl alcohol copolymer (hereinafter also referred to as the content of ethylene units) is preferably 20 to 80 mol% relative to all monomer units constituting EVOH. In addition, from the viewpoint of easily improving the molding processability of the obtained acetalized product or the softness, barrier properties and transparency of the obtained resin film, the ethylene content is preferably 20 mol% or more, more preferably 25 mol% or more, further preferably 30 mol% or more, and particularly preferably 32 mol% or more (for example, 35 mol% or more), and from the viewpoint of easily improving the heat resistance of the obtained acetalized product, it is preferably 80 mol% or less, more preferably 60 mol% or less, further preferably 55 mol% or less, particularly preferably 50 mol% or less, further preferably 48 mol% or less, more particularly preferably 44 mol% or less, further particularly preferably 42 mol% or less, further particularly preferably 38 mol% or less, and most preferably 36 mol% or less.

[0122] The saponification degree of EVOH is not particularly limited, and for example, from the viewpoint of thermal decomposition resistance, it is preferably 95 mol% or more, more preferably 98 mol% or more, further preferably 99 mol% or more, and particularly preferably 99.9 mol% or more. The upper limit of the saponification degree is not particularly limited, and for example, it may be 100 mol% or less.

[0123] From the viewpoint of easily improving the barrier properties of the obtained acetalized product, the content of the vinyl alcohol unit of the ethylene vinyl alcohol copolymer is preferably 40 mol% or more, more preferably 45 mol% or more, and further preferably 50 mol% or more, based on the total monomer units constituting EVOH. From the viewpoint of easily improving the transparency of the obtained acetalized product, it is preferably 80 mol% or less, more preferably 75 mol% or less, further preferably 70 mol% or less, particularly preferably 65 mol% or less, and further particularly preferably 55 mol% or less.

[0124] In the present invention, the ethylene vinyl alcohol copolymer may further contain monomer units derived from monomers copolymerizable with these units (hereinafter also referred to as other monomer units) in addition to containing ethylene units, vinyl alcohol units and vinyl ester units, within the scope of not impairing the effects of the present invention. As the aforementioned other monomer units, the same monomer units as the other monomer units that may be contained in the acetal compound may be cited. When the ethylene vinyl alcohol copolymer contains other monomer units, the content thereof is preferably 15 mol % or less, more preferably 10 mol % or less.

[0125] The contents of the ethylene unit, the vinyl alcohol unit, and other monomer units contained as needed in the EVOH of the present invention can be determined by NMR measurement, for example, by the method described in Examples.

[0126] The copolymerization form of the ethylene vinyl alcohol copolymer is not particularly limited, and may be any of a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer, and the like.

[0127] In one embodiment of the present invention, from the viewpoint of easily suppressing the degradation of the obtained acetal product due to heat during the molding process, the melt flow rate of the ethylene vinyl alcohol copolymer measured under the conditions of 190° C. and 2.16 kg in accordance with JIS K7210:2014 is preferably 1 to 30 g / 10 min, more preferably 1.5 to 20 g / 10 min, further preferably 2 to 10 g / 10 min, and particularly preferably 2.5 to 9 g / 10 min.

[0128] The method for producing the ethylene vinyl alcohol copolymer as a porous body is not particularly limited, and the ethylene vinyl alcohol copolymer can be produced by a known method. As an example, a method for producing a pellet-like EVOH porous body will be described.

[0129] The pelletized EVOH porous body can be manufactured, for example, as described in Japanese Patent Publication No. 11-293077 or Japanese Patent Publication No. 2002-121290, by the following operations: a process of preparing a composition containing an ethylene vinyl alcohol copolymer and containing at least one solvent selected from water and alcohol; a process of extruding the aforementioned composition into a coagulation liquid in the form of strands, and then cutting it after coagulation; or a method of directly cutting the aforementioned composition in a molten state.

[0130] The EVOH contained in the aforementioned composition can be obtained by copolymerizing ethylene and a vinyl ester-based monomer and saponifying the resulting copolymer.

[0131] Examples of vinyl ester monomers used as raw materials for EVOH include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl octanoate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, and vinyl benzoate. Among these, vinyl acetate is preferred.

[0132] The method for copolymerizing ethylene and vinyl ester monomers is not particularly limited, and the copolymerization can be carried out by a conventionally known method, such as solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, etc. The polymerization initiator that can be used in the above-mentioned copolymerization can be appropriately selected from conventionally known polymerization initiators such as azo initiators, peroxide initiators, and redox initiators according to the polymerization method.

[0133] The saponification of the copolymer of ethylene and vinyl ester monomers can be carried out by alcoholysis or hydrolysis using a conventionally known alkali catalyst or acid catalyst. Among them, saponification using methanol as a solvent and a caustic soda (NaOH) catalyst is simple and therefore preferred.

[0134] The alcohol that can be included in the composition is not particularly limited as long as it is a solvent that can dissolve EVOH, and examples thereof include methanol, ethanol, propanol, isopropanol, etc. Among these alcohols, alcohols with a boiling point of 100° C. or less are preferred, and methanol is particularly preferred, because they have a low boiling point and are easily removed.

[0135] When the composition contains water as a solvent, the composition can be prepared by directly adding water to EVOH or a composition containing EVOH and an alcohol, or by concentrating an EVOH alcohol solution obtained by dissolving EVOH in an alcohol as needed, and then adding water to the EVOH alcohol solution to such an extent that EVOH does not precipitate. In addition, water vapor can be introduced into EVOH or a composition containing EVOH and an alcohol, and at least a part of the alcohol can be discharged together with the water vapor to obtain a composition containing EVOH and water or a composition containing EVOH, water and an alcohol.

[0136] The alcohol that can be used to prepare the EVOH alcohol solution is not particularly limited as long as it is a solvent that can dissolve EVOH. Examples include the same alcohols that can be included in the aforementioned composition. From the perspective of low boiling point and easy removal, alcohols with a boiling point of 100°C or less are preferred, and methanol is particularly preferred.

[0137] The alcohol content in the EVOH alcohol solution is preferably 1 to 500 parts by mass, more preferably 5 to 200 parts by mass, based on 100 parts by mass of EVOH.

[0138] In the case where the aforementioned composition contains water, the water content is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 50 parts by mass or more relative to 100 parts by mass of EVOH, from the viewpoint of easily acetalizing EVOH uniformly and easily removing the neutralized salt generated by neutralization after the acetalization reaction. In addition, from the viewpoint of easily improving the strength of the obtained porous body and facilitating the efficient production of acetalized products, the water content is preferably 500 parts by mass or less, more preferably 300 parts by mass or less, and further preferably 200 parts by mass or less.

[0139] In the case where the aforementioned composition contains alcohol, the content of alcohol is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 50 parts by mass or more relative to 100 parts by mass of EVOH, from the viewpoint of easily acetalizing EVOH uniformly and easily removing the neutralized salt generated by neutralization after the acetalization reaction. In addition, from the viewpoint of easily improving the strength of the obtained porous body and facilitating the efficient production of acetalized products, the content of alcohol is preferably 500 parts by mass or less, more preferably 300 parts by mass or less, and further preferably 200 parts by mass or less.

[0140] The coagulation liquid for coagulating the composition is not particularly limited as long as it is a solvent capable of coagulating EVOH, but water, alcohol, or a mixed solvent of water and alcohol is preferably used as the coagulation liquid.

[0141] From the viewpoint of easily coagulating the composition sufficiently, the temperature of the coagulation liquid is preferably 0 to 50° C., more preferably 0 to 30° C. From the viewpoint of fluidity of EVOH, the temperature of the composition when extruding the composition into the coagulation liquid is preferably 90 to 150° C., more preferably 95 to 140° C.

[0142] As described above, by extruding the composition into a coagulation liquid and coagulating it, the obtained coagulated body becomes a porous body with oriented pores.

[0143] The obtained strand-shaped solidified body may be cut by, for example, a strand cutter or the like. By cutting the obtained strand-shaped solidified body by a strand cutter or the like, a pellet-shaped EVOH porous body can be obtained.

[0144] Examples of a method for directly cutting the composition in a molten state to obtain pelletized EVOH porous bodies include a method of obtaining pelletized EVOH porous bodies from a melt of the composition using an extruder by heat cutting or heat cutting in water.

[0145] As described above, the melt of the composition is extruded and granulated, whereby the obtained pellets are formed into a porous body in which pores are oriented.

[0146] The method for producing the powdery EVOH porous body is not particularly limited, and the powdery EVOH porous body can be obtained, for example, by pulverizing the pelletized porous body obtained by the above method using a pulverizer or the like.

[0147] The EVOH porous body may contain a solvent. When the contained solvent is a good solvent for EVOH, it is preferred to reduce the amount of the good solvent in EVOH by drying, etc. to a level where the pores of the EVOH porous body are not clogged. In addition, when the contained solvent is a poor solvent for EVOH such as water, the EVOH porous body may contain 5 to 200 parts by mass of a poor solvent such as water relative to 100 parts by mass of the EVOH porous body.

[0148] In the method of the present invention, when a non-porous body (a non-porous body refers to a body without pores) of ethylene vinyl alcohol copolymer (hereinafter also referred to as "EVOH non-porous body" or simply "non-porous body") is used as a raw material, by selecting an acetalization method (especially an acetalization method using the preferred specific surface area and / or preferred average particle size and / or preferred aldehyde impregnation time and / or preferred acetalization reaction time and / or preferred acetalization catalyst concentration of the raw material EVOH), etc., the EVOH can be uniformly acetalized and the symmetry coefficient of the obtained acetalized product can be adjusted to the above-mentioned range. Therefore, even if solid EVOH is acetalized by a non-uniform method, intermolecular cross-linking of EVOH is not likely to occur, and an acetalized product with excellent transparency can be obtained.

[0149] In one embodiment of the present invention, from the viewpoint of handling, the average particle size of the EVOH non-porous body is preferably 0.8 μm or more, more preferably 1.0 μm or more, further preferably 10 μm or more, and particularly preferably 50 μm or more. In addition, the above-mentioned average particle size is preferably 1 mm or less, more preferably 0.5 mm or less, further preferably 0.4 mm or less, and particularly preferably 0.3 mm or less. If the average particle size of the EVOH non-porous body is below the above-mentioned upper limit, it is easy to uniformly acetalize the EVOH, and it is easy to improve the transparency of the acetalized product obtained thereby. This is considered to be because: by using an EVOH non-porous body having a larger specific surface area due to an average particle size below the above upper limit, the proportion of the central part of the EVOH non-porous body that does not or is not easily acetalized can be reduced. In addition, when at least a portion of the aldehyde described later is impregnated into EVOH, the aldehyde as an acetalizing agent will enter the concave-convex or gaps that are usually present on the surface of the EVOH non-porous body, thereby even the inside of the EVOH non-porous body will be acetalized, and more uniform acetalization can be achieved, and as a result, an acetalized product with a narrow distribution of acetalized products can be obtained. The average particle size can be measured by the method described in the examples, for example.

[0150] The shape of the EVOH non-porous body is not particularly limited, and examples thereof include powder, granular, flake, bead, irregular shapes, etc. Among these, the non-porous body is preferably in a powder or granular shape. It should be noted that in the present invention, the granular non-porous body refers to a solid non-porous body with a substantially constant size such as a sphere, a cylinder, an elliptical column, a polygonal column, and the like, and its cross section may be circular, elliptical, polygonal, etc.

[0151] When the EVOH non-porous body in the present invention is in the form of pellets, the pellet-shaped non-porous body can be produced by the following methods as described below: a method in which the ethylene vinyl alcohol copolymer composition is extruded into a coagulation liquid to coagulate it into a strand shape, and then the obtained strand-shaped coagulated material is cut into a specified length using a strand cutter or the like; or a method in which the ethylene vinyl alcohol copolymer composition is directly cut in a molten state, etc.

[0152] As ethylene vinyl alcohol copolymer, for example, a substance obtained by copolymerizing ethylene with a vinyl ester monomer and saponifying the obtained copolymer can be cited. In one embodiment of the present invention, the ethylene content of the ethylene vinyl alcohol copolymer (hereinafter also referred to as the content of the ethylene unit) is preferably 20 to 80 mol% relative to all monomer units constituting EVOH. In addition, from the viewpoint of easily improving the molding processability of the obtained acetalized product or the softness, barrier properties and transparency of the obtained resin film, the ethylene content is preferably 20 mol% or more, more preferably 25 mol% or more, further preferably 30 mol% or more, and particularly preferably 32 mol% or more (for example, 35 mol% or more), and from the viewpoint of easily improving the heat resistance of the obtained acetalized product, it is preferably 80 mol% or less, more preferably 60 mol% or less, further preferably 55 mol% or less, particularly preferably 50 mol% or less, further preferably 48 mol% or less, more particularly preferably 44 mol% or less, further particularly preferably 42 mol% or less, and further particularly preferably 38 mol% or less.

[0153] The saponification degree of EVOH is not particularly limited, and for example, from the viewpoint of thermal decomposition resistance, it is preferably 95 mol% or more, more preferably 98 mol% or more, further preferably 99 mol% or more, and particularly preferably 99.9 mol% or more. The upper limit of the saponification degree is not particularly limited, and for example, it may be 100 mol% or less.

[0154] From the viewpoint of easily improving the barrier properties of the obtained acetalized product, the content of the vinyl alcohol unit of the ethylene vinyl alcohol copolymer is preferably 40 mol% or more, more preferably 45 mol% or more, and further preferably 50 mol% or more, based on the total monomer units constituting EVOH. From the viewpoint of easily improving the transparency of the obtained acetalized product, it is preferably 80 mol% or less, more preferably 75 mol% or less, further preferably 70 mol% or less, particularly preferably 65 mol% or less, and further particularly preferably 55 mol% or less.

[0155] In the present invention, the ethylene vinyl alcohol copolymer may further contain monomer units derived from monomers copolymerizable with these units (hereinafter also referred to as other monomer units) in addition to containing ethylene units, vinyl alcohol units and vinyl ester units, within the scope of not impairing the effects of the present invention. As the aforementioned other monomer units, the same monomer units as the other monomer units that may be contained in the acetal compound may be cited. When the ethylene vinyl alcohol copolymer contains other monomer units, the content thereof is preferably 15 mol % or less, more preferably 10 mol % or less.

[0156] The contents of the ethylene unit, the vinyl alcohol unit, and other monomer units contained as needed in the EVOH of the present invention can be determined by NMR measurement, for example, by the method described in Examples.

[0157] The copolymerization form of the ethylene vinyl alcohol copolymer is not particularly limited, and may be any of a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer, and the like.

[0158] In one embodiment of the present invention, from the viewpoint of easily suppressing the degradation of the obtained acetal product due to heat during the molding process, the melt flow rate of the ethylene vinyl alcohol copolymer measured under the conditions of 190° C. and 2.16 kg in accordance with JIS K7210:2014 is preferably 1 to 30 g / 10 min, more preferably 1.5 to 20 g / 10 min, further preferably 2 to 10 g / 10 min, and particularly preferably 2.5 to 9 g / 10 min.

[0159] The method for producing the non-porous ethylene vinyl alcohol copolymer is not particularly limited, and the non-porous ethylene vinyl alcohol copolymer can be produced by a known method.

[0160] The method for producing the powdery EVOH non-porous body is not particularly limited, and the non-porous body or porous body obtained by a known method can be obtained by pulverizing the non-porous body or porous body, for example, using a pulverizer, etc. The pulverized porous body is a powdery EVOH non-porous body, i.e., it has no pores, which can be confirmed by, for example, electron microscopic observation.

[0161] In one embodiment of the present invention, the content of EVOH contained in the EVOH dispersion prepared by step (i) is preferably 5 mass% or more, more preferably 10 mass% or more, further preferably 15 mass% or more, and is preferably 70 mass% or less, more preferably 60 mass% or less, further preferably 50 mass% or less, relative to the total mass of the dispersion.

[0162] The aldehyde contained in the EVOH dispersion is not particularly limited. Examples thereof include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, hexanal, benzaldehyde, isobutylaldehyde, 2-ethylhexylaldehyde, 2-methylbutylaldehyde, trimethylacetaldehyde, 2-methylpentylaldehyde, 2,2-dimethylbutylaldehyde, 2-ethylbutylaldehyde, 3,5,5-trimethylhexylaldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, and n-dodecylaldehyde.

[0163] In addition, it may be an aldehyde having a reactive carbon-carbon double bond, and examples thereof include acrolein, methacrolein, crotonaldehyde, 3-butenal, 2-methyl-2-butenal, 2-methyl-3-butenal, 2,2-dimethyl-3-butenal, 3-methyl-2-butenal, 3-methyl-3-butenal, 2-pentenal, 2-methyl-2-pentenal, 3-pentenal, 3-methyl-4-pentenal, 4-pentenal, 4-methyl-4-pentenal, 2-hexenal, 3-hexenal, 4-hexenal, 5-hexenal, 7-octenal, 10-undecenal, 2-ethylcrotonaldehyde, 3-(dimethylamino)acrolein, myristenal, palmitomyraldehyde, olealdehyde, anti-olealdehyde, iso-olealdehyde, gadaldehyde, Alkenals having 3 to 30 carbon atoms, such as mustardaldehyde, neuraldehyde, linolealdehyde, citronellal, cinnamaldehyde and vanillin, are preferably alkenals having 3 to 25 carbon atoms; alkadienals having 5 to 30 carbon atoms, such as 2,4-pentadienal, 2,4-hexadienal, 2,6-nonadienal and citral, are preferably alkanadienals having 5 to 25 carbon atoms; alkadienals having 7 to 30 carbon atoms, such as linolenic acid and octadecatrienal, are preferably alkantrienals having 7 to 25 carbon atoms; alkanetraenals having 9 to 30 carbon atoms, such as octadecatetraenal and arachidonic acid, are preferably alkantetraenals having 9 to 25 carbon atoms; unsaturated aldehydes such as alkanepentaenals having 11 to 30 carbon atoms, such as eicosapentaenal, are preferably alkanenepentaenals having 11 to 25 carbon atoms.

[0164] The aldehyde contained in the EVOH dispersion may be an aldehyde derivative. As an aldehyde derivative, a substance obtained by forming an acetal or hemiacetal with a hydroxyl group and an aldehyde group in a molecule can be exemplified. An aldehyde derivative obtained by forming an acetal or hemiacetal with a hydroxyl group and an aldehyde group in a molecule has a cyclic structure, and one or two of the carbon atoms constituting the ring are optionally substituted with an alkyl group, preferably substituted with a methyl group or an ethyl group, and more preferably substituted with a methyl group. As examples of specific aldehyde derivatives, 2-hydroxytetrahydrofuran, 2-hydroxytetrahydropyran, 4-methyl-2-hydroxytetrahydrofuran and 4-methyl-2-hydroxytetrahydropyran can be cited.

[0165] These aldehydes can be used alone or in combination of two or more. In one embodiment of the present invention, from the viewpoint of easily improving the flexibility, heat resistance and transparency of the obtained acetal compound, the aldehyde is preferably butyl aldehyde, isobutyl aldehyde, or n-octyl aldehyde. From the aspect of being able to balance the flexibility, heat resistance and barrier properties of the obtained acetal compound with a high dimension, isobutyl aldehyde and n-octyl aldehyde are particularly preferred.

[0166] The content of aldehyde contained in the EVOH dispersion is not particularly limited, and can be appropriately adjusted according to the desired degree of acetalization. In one embodiment of the present invention, from the viewpoint of easily improving the transparency and flexibility of the obtained acetalized product, the content of aldehyde is preferably 1 to 40 parts by mass, more preferably 1.5 to 35 parts by mass, and further preferably 2 to 30 parts by mass relative to 100 parts by mass of EVOH.

[0167] The method of the present invention performs acetalization by solid-liquid reaction. Therefore, the solvent contained in the EVOH dispersion is a poor solvent for EVOH and its acetalate, preferably a solvent containing water, more preferably water.

[0168] The method for preparing the EVOH dispersion is not particularly limited, and for example, the dispersion may be prepared by adding aldehyde to a dispersion obtained by dispersing EVOH in a solvent, or by adding a solvent to a mixture of EVOH and aldehyde.

[0169] In the method of the present invention, after preparing the aforementioned EVOH dispersion and before adding the catalyst, at least a portion of the aldehyde is impregnated into the ethylene vinyl alcohol copolymer, thereby allowing the aldehyde to penetrate into the interior of the EVOH porous body or allowing the aldehyde to enter the concave and convex parts or gaps on the surface of the EVOH non-porous body, thereby enabling the EVOH to be uniformly acetalized. Therefore, it is easy to adjust the symmetry coefficient of the obtained acetalized product within the above-mentioned range, and it is easy to improve the transparency.

[0170] The temperature for impregnating EVOH with aldehyde is not particularly limited. From the viewpoint of enabling faster impregnation of EVOH with aldehyde, the temperature may be, for example, 20° C. or higher, preferably 30° C. or higher, more preferably 40° C. or higher, and further preferably 50° C. or higher. From the viewpoint of inhibiting fusion of EVOHs, the temperature is preferably 100° C. or lower, more preferably 90° C. or lower, and further preferably 80° C. or lower.

[0171] The time for impregnating the aldehyde into the EVOH porous body can be appropriately selected according to the impregnation temperature and the pore structure of the EVOH porous body, and is preferably more than 2 hours, more preferably more than 2.5 hours, further preferably more than 3 hours, further preferably more than 4 hours, and particularly preferably more than 5 hours. In addition, the upper limit is not particularly limited, and for example, it can be 10 hours. The impregnation time of the aldehyde in the EVOH non-porous body can be appropriately selected according to the impregnation temperature and the average particle size of the EVOH non-porous body, and is preferably more than 4 hours, more preferably more than 5 hours, further preferably more than 6 hours, further preferably more than 8 hours, and particularly preferably more than 10 hours. In addition, the upper limit is not particularly limited, and for example, it can be 24 hours.

[0172] <Step (ii)>

[0173] Step (ii) is a step of acetalizing EVOH by adding a catalyst to the EVOH dispersion prepared by step (i) after impregnating EVOH with aldehyde. In the method of the present invention, the acetalization is carried out by solid-liquid reaction. By using solid-liquid reaction to carry out acetalization, it is easy to adjust the Tm / Tg (K / K) of the obtained acetalized product to the above range, so it is easy to maintain transparency and improve flexibility and heat resistance. In addition, by using solid-liquid reaction to carry out acetalization, the generated acetalized product can be separated from the reaction solution by filtering operation, and the acetalized product can be easily produced efficiently. In addition, it is easy to produce the acetalized product with a high yield. It should be noted that in the present invention, the method of acetalization by solid-liquid reaction refers to: by using a poor solvent for EVOH and the acetalized product of EVOH generated by acetalization as a solvent for the acetalization reaction, EVOH and the acetalized product are not dissolved in the solvent in the acetalization process, but the generated acetalized product is dispersed in the dispersion to obtain the solid form.

[0174] The catalyst for acetalization is not particularly limited and may be an inorganic acid or an organic acid, and examples thereof include acidic catalysts such as acetic acid, p-toluenesulfonic acid, nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and carbonic acid. Among these catalysts, inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid are preferred from the viewpoints of easily increasing the reaction rate of the acetalization reaction, easily washing out the generated acetalized product, and easily producing the acetalized product efficiently.

[0175] The amount of catalyst added to the EVOH dispersion can be appropriately selected according to the type of catalyst and / or the reaction temperature. The catalyst concentration in the EVOH dispersion is preferably 0.001 to 1.0 mol / L, more preferably 0.01 to 0.8 mol / L, further preferably 0.02 to 0.25 mol / L, and further preferably 0.02 to 0.1 mol / L.

[0176] The amount of the catalyst in the EVOH dispersion is preferably 1 to 75 parts by mass, 5 to 50 parts by mass, and more preferably 7.5 to 35 parts by mass based on 100 parts by mass of EVOH.

[0177] The method of adding the catalyst to the EVOH dispersion is not particularly limited. For example, the catalyst may be added to the EVOH dispersion at once or in multiple times. From the viewpoint of easily obtaining an acetalized product with low haze, excellent transparency and barrier properties, the catalyst is preferably added to the EVOH dispersion in multiple times, particularly preferably in two times.

[0178] When the catalyst is added to the EVOH dispersion in multiple times, the amount of the catalyst added in the first time is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less relative to the total amount added. If the amount of the catalyst added in the first time is below the above upper limit, the distribution of the acetalization degree becomes narrow, and the transparency of the obtained acetalized product is easily improved.

[0179] From the viewpoint of easily maintaining the pores of the EVOH porous body and preventing the fusion of the EVOH porous body and the EVOH non-porous body during the reaction, the reaction temperature of the acetalization is preferably below the glass transition temperature of EVOH. The above reaction temperature is more preferably 10 to 80°C, more preferably 20 to 70°C, and further preferably 30 to 60°C. In addition, the acetalization can be carried out in the air, in an inert gas such as nitrogen or argon, and can be carried out under any conditions of normal pressure, pressurized pressure, or reduced pressure.

[0180] After the acetalization reaction, the obtained reaction solution can be neutralized with a base as needed, and then the acetal product can be separated and purified from the reaction solution by conventional methods, such as filtration, concentration, reprecipitation, recrystallization and other separation means. The neutralization salt produced by neutralization is preferably removed by washing or the like. The base that can be used for neutralization is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium bicarbonate, potassium carbonate and the like.

[0181] The acetalization reaction time, i.e., the time from the addition of the catalyst to the completion of the acetalization reaction (until neutralization or separation and purification), is preferably 2 hours or more, more preferably 6 hours or more, further preferably 8 hours or more, and particularly preferably 12 hours or more. The upper limit of the acetalization reaction time is not particularly limited, and may be, for example, 30 hours.

[0182] The present inventors have discovered that by adopting the above-mentioned preferred acetalization method, in particular by adjusting at least one, preferably at least two, and more preferably all of the specific surface area and / or average particle size, aldehyde impregnation time, acetalization catalyst concentration, and acetalization reaction time of the raw material EVOH resin to the above-mentioned preferred ranges, it is possible to produce an acetalized product capable of forming a resin film having better barrier properties, transparency, stretchability, flexibility, and heat resistance.

[0183] 〔Composition〕

[0184] The present invention also relates to a composition comprising: the acetalized product of the present invention (hereinafter also referred to as "acetalized product (A)" or "(A)"); and (B) one or more resins selected from the group consisting of (B-1) an acetalized product of an ethylene vinyl alcohol copolymer other than (A), (B-2) an ethylene vinyl alcohol copolymer, and (B-3) a resin other than (B-1) and (B-2).

[0185] The composition of the present invention contains an acetal compound (A), and therefore, can form a resin film having excellent barrier properties, transparency, stretchability, flexibility and heat resistance. The content of the acetal compound (A) in the composition of the present invention is preferably 5% by mass or more, more preferably 7.5% by mass or more, further preferably 10% by mass or more, further preferably 20% by mass or more, further preferably 25% by mass or more. If the content of the acetal compound (A) is above the above lower limit, it is easy to obtain a resin film having excellent barrier properties, transparency, stretchability, flexibility and heat resistance. The upper limit is not particularly limited, for example, it can be less than 100% by mass.

[0186] Examples of the acetalized product (B-1) of ethylene vinyl alcohol copolymer other than (A) include those not satisfying the formula (1), the formula (2), and 150 cc·20 μm / m 2Acetals of ethylene vinyl alcohol copolymers having one or more of the oxygen permeability rates at 20°C and 65%RH below ·day·atm. The acetal (B-1) may be a resin comprising ethylene units, vinyl alcohol units, acetal units and, depending on the circumstances, vinyl ester units. The content of each unit of the acetal (B-1), degree of acetalization, Tm, Tg, MFR and tensile modulus may be the same as or different from those described in the item [Acetals of ethylene vinyl alcohol copolymers]. The acetal (B-1) may be used alone or in combination of two or more different units having different contents, etc.

[0187] In one embodiment of the present invention, from the viewpoint of easily improving the transparency of the composition, the Tm / Tg(K / K) of the acetal compound (B-1) is preferably less than 1.27, more preferably 1.25 or less, further preferably 1.23 or less, and particularly preferably 1.21 or less, and from the viewpoint of easily improving the heat resistance of the composition, it is preferably 1.10 or more, more preferably 1.12 or more, and further preferably 1.15 or more. The above Tm / Tg(K / K) can be obtained by the same method as that of the acetal compound (A).

[0188] From the viewpoint of easily improving the gas barrier properties of the obtained resin film, the content of the resin (B-1) in the composition of the present invention is preferably 75 parts by mass or less relative to 100 parts by mass of the acetalized product (A). From the viewpoint of easily improving the transparency and / or flexibility, the content of the resin (B-1) relative to 100 parts by mass of the acetalized product (A) can be, for example, 0 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, further preferably 20 parts by mass or more, and particularly preferably 25 parts by mass or more.

[0189] Examples of ethylene vinyl alcohol copolymers (B-2) include ethylene vinyl alcohol copolymers described in the section [Method for producing acetalized products of ethylene vinyl alcohol copolymers] as raw materials for the acetalized products of the present invention. Among them, the ethylene vinyl alcohol copolymer as the resin (B-2) may be a porous body or may not be a porous body. The ethylene vinyl alcohol copolymer (B-2) may be used alone or in combination of two or more different units having different contents.

[0190] From the viewpoint of easily improving the flexibility of the obtained resin film, the content of the resin (B-2) in the composition of the present invention is preferably 350 parts by mass or less relative to 100 parts by mass of the acetalized product (A). From the viewpoint of easily improving the gas barrier properties and / or heat resistance of the composition, the content of the resin (B-2) relative to 100 parts by mass of the acetalized product (A) may be, for example, 0 parts by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, and particularly preferably 100 parts by mass or more.

[0191] Examples of the resin (B-3) other than (B-1) and (B-2) include 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 copolymers, high-impact polystyrene, AS resins, ABS resins, AES resins, AAS resins, ACS resins, and MBS resins; methyl methacrylate-based polymers, and methyl methacrylate-styrene copolymers; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyamides such as nylon 6, nylon 66, and 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 thermoplastic elastomers such as SEPS, SEBS, and SIS; olefin rubbers such as IR, EPR, and EPDM. These resins may be used alone or in combination of two or more.

[0192] As the polyamide elastomer, thermoplastic elastomers including hard segments formed by polyamide and soft segments formed by polyethers can be listed. As polyamide constituting the hard segment, nylon 6, nylon 66, nylon 11 and nylon 12 can be listed, among which nylon 12 is preferred. As polyether constituting the soft segment, polyethylene glycol, polypropylene glycol and polytetramethylene glycol can be listed. As the polyamide elastomer, commercially available products can be used. As examples of commercially available products of polyamide elastomers, "UBESTA" (registered trademark) XPA manufactured by Ube Industries, Ltd., "Pebax" (registered trademark) 33 series, 53 series, MV series, MH series, HD series, MP series, etc. manufactured by Arkema can be listed.

[0193] From the viewpoint of easily improving the gas barrier properties of the obtained resin film, the content of the resin (B-3) in the composition of the present invention is preferably 100 parts by mass or less relative to 100 parts by mass of the acetalized product (A). From the viewpoint of easily improving the flexibility and / or adhesiveness of the composition, the content of the resin (B-3) relative to 100 parts by mass of the acetalized product (A) may be, for example, 0 parts by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, and particularly preferably 100 parts by mass or more.

[0194] Among the resins (B-1) to (B-3), from the viewpoint of easily improving the heat resistance, transparency and barrier properties of the obtained resin film, acetals of ethylene vinyl alcohol copolymers (B-1) and ethylene vinyl alcohol copolymers (B-2) other than (A) are preferred, and ethylene vinyl alcohol copolymers (B-2) are more preferred.

[0195] Various additives may be blended into the composition of the present invention as required. Examples of such additives include antioxidants, ultraviolet absorbers, light stabilizers, alkali metal salts, alkaline earth metal salts, carboxylic acid compounds, phosphoric acid compounds, plasticizers, heat stabilizers, antistatic agents, lubricants, colorants, and fillers. In addition, as described later, when crosslinking is applied to the resin film of the present invention, the barrier material of the present invention, or the composition of the present invention in the molded body, it is preferred to blend a crosslinking aid as an additive. The additives may be blended alone or in combination of two or more.

[0196] The content of various additives varies according to their types and can be appropriately selected within the range that does not damage the effect of the present invention. When the additives are mixed, the total content thereof can be, for example, 9% by mass or less, preferably 7% by mass or less, more preferably 5% by mass or less, and further preferably 4% by mass or less relative to the total mass of the composition.

[0197] Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. These antioxidants may be used alone or in combination of two or more.

[0198] Examples of phenolic antioxidants include acrylate compounds such as 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate and 2,4-di-tert-amyl-6-(1-(3,5-di-tert-amyl-2-hydroxyphenyl)ethyl)phenyl acrylate; 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(4-methyl- 6-tert-butylphenol), 4,4'-butylidenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butylm-cresol), ethylenebis(oxyethylene)bis(3-(5-tert-butyl-4-hydroxym-tolyl)propionate, 4,4'-thiobis(3-methyl-6-tert-butylphenol), bis(3-cyclohexyl-2-hydroxy-5-methylphenyl)methane, 3,9-bis(2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl)-2 , 4,8,10-tetraoxaspiro[5,5]undecane, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetrakis(methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate)methane, triethylene glycol bis(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate) or hexamethylene bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate Alkyl-substituted phenol compounds; phenol compounds containing triazine groups such as 6-(4-hydroxy-3,5-di-tert-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-tert-butylanilino)-2,4-bis-octylthio-1,3,5-triazine or 2-octylthio-4,6-bis(3,5-di-tert-butyl-4-oxyanilino)-1,3,5-triazine, etc.

[0199] Examples of the phosphorus antioxidant include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl)phosphite, tris(dinonylphenyl)phosphite, tris(2-tert-butyl-4-methylphenyl)phosphite, tris(cyclohexylphenyl)phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or 10-decylphosphite. Monophosphite compounds such as oxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene; diphosphite compounds such as 4,4'-butylidenebis(3-methyl-6-tert-butylphenyl-di(tridecyl)phosphite), 4,4'-isopropylidenebis(phenyl-dialkyl(C12-C15)phosphite), 4,4'-isopropylidenebis(diphenylmonoalkyl(C12-C15)phosphite), 1,1,3-tris(2-methyl-4-di(tridecyl)phosphite-5-tert-butylphenyl)butane or tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenephosphite, etc. Among these, monophosphite compounds are preferred.

[0200] Examples of the sulfur-based antioxidant include dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, laurylstearyl-3,3'-thiodipropionate, pentaerythritol-tetrakis(β-laurylthiopropionate), and 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane.

[0201] The amount of the antioxidant to be added 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, based on 100 parts by mass of the acetalized product (A).

[0202] Examples of the ultraviolet absorber include 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α'-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-tert-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-tert-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, and 2-(3,5-di-tert-butyl-5-methyl-2-hydroxyphenyl)-5 Benzotriazole-based ultraviolet light absorbers such as 2-chlorobenzotriazole, 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole or 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole; benzoate-based ultraviolet light absorbers such as 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate or hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, etc.

[0203] The content of the ultraviolet absorber is preferably 0 to 50,000 ppm, more preferably 10 to 50,000 ppm, and even more preferably 100 to 10,000 ppm based on the mass of the acetalized product (A).

[0204] Examples of the light stabilizer 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-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonate, 4-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy)-1-(2-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy)ethyl)-2,2,6,6-tetramethylpiperidine, and bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) sebacate.

[0205] Examples of the plasticizer include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphoric acid ester, 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 ester, di(2-butoxyethyl) glutarate, di(2-butoxyethoxyethyl) adipate (DBEEA), di(2-butoxyethoxyethyl) sebacate (DBEES), ... Di(2-hexoxyethoxyethyl) azelaic acid ester, di(2-butoxyethoxyethyl) glutarate, di(2-hexyloxyethyl) adipate, di(2-hexyloxyethyl) sebacate, di(2-hexyloxyethyl) azelaic acid ester, di(2-hexyloxyethyl) glutarate, di(2-hexyloxyethoxyethyl) adipate, di(2-hexyloxyethoxyethyl) sebacate, di(2-hexyloxyethoxyethyl) azelaic acid ester, di(2-hexyloxyethoxyethyl) glutarate, di(2-butoxyethyl) phthalate and / or di(2-butoxyethoxyethyl) phthalate, polypropylene glycol (PPG), etc. Among these plasticizers, plasticizers having a total of 28 or more carbon atoms and oxygen atoms constituting the molecule are preferred. 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, and polypropylene glycol (PPG: average molecular weight 400). These plasticizers may be used alone or in combination of two or more.

[0206] Examples of the heat stabilizer include hydrotalcite compounds, hindered phenol-based heat stabilizers, hindered amine-based heat stabilizers, and metal salts of higher aliphatic carboxylic acids (eg, calcium stearate, magnesium stearate, etc.).

[0207] Examples of the antistatic agent include pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyolefins, polyethylene oxide, and carbowax.

[0208] Examples of the lubricant include ethylene bisstearic acid amide and butyl stearate.

[0209] Examples of the colorant include carbon black, phthalocyanine, quinacridone, indoline, azo pigments, and Indian red.

[0210] Examples of the filler include glass fiber, asbestos, barite, and calcium silicate.

[0211] Examples of crosslinking aids include multifunctional allyl compounds and multifunctional (meth) acrylic compounds. Specific examples include triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), pentaerythritol tetramethacrylate (PETMA), glutaraldehyde (GA), ethylene glycol dimethacrylate (EGDMA), diallyl maleate (DAM), dipropyl maleate (DPM), dipropyl monoallyl cyanurate (DPMAC), trimethylolpropane triacrylate (TMPTAT), tetraethylene glycol diacrylate (TEGDA), 1,6-hexanediol diacrylate, tetramethylolmethane tetraacrylate, dipropyl succinate, diallyl fumarate, diallyl phthalate, etc. Among these, triallyl cyanurate and triallyl isocyanurate are particularly preferred.

[0212] In one embodiment of the present invention, from the viewpoint of easily suppressing degradation caused by heat during molding processing, the melt flow rate of the composition of the present invention measured under the conditions of 190° C. and 2.16 kg in accordance with JIS K7210:2014 is preferably 1 to 30 g / 10 minutes, more preferably 2 to 20 g / 10 minutes, further preferably 3 to 10 g / 10 minutes, and particularly preferably 2.5 to 9 g / 10 minutes.

[0213] In one embodiment of the present invention, the oxygen permeability of the composition of the present invention at 20°C and 65% RH is preferably 150 cc·20 μm / m 2 ·day·atm or less, more preferably 120cc·20μm / m 2 ·day·atm or less, more preferably 100cc·20μm / m 2 ·day·atm or less, more preferably 75cc·20μm / m 2 ·day·atm or less, particularly preferably 30cc·20μm / m 2 The lower limit of the oxygen permeation rate is not particularly limited, and may be, for example, 0 cc·20 μm / m 2 ·day·atm or more.

[0214] The oxygen permeation rate can be adjusted by appropriately adjusting the blending ratio of the acetalized product (A) and the resin (B) in the composition.

[0215] The oxygen permeation rate can be measured by the same method as the oxygen permeation rate of the acetal compound of the present invention at 20° C. and 65% RH.

[0216] The tensile modulus of the composition of the present invention in the tensile strength and elongation measurement at 23°C and 50% RH is preferably 2000 MPa or less, more preferably 1900 MPa or less, further preferably 1800 MPa or less, further preferably 1700 MPa or less, particularly preferably 1600 MPa or less, and more particularly preferably 1500 MPa or less. The lower limit of the tensile modulus is not particularly limited, but is preferably 10 MPa or more, more preferably 100 MPa or more, and further preferably 1000 MPa or more.

[0217] The tensile elongation at break of the composition of the present invention in the tensile strength and elongation measurement at 23°C and 50%RH is preferably 150% or more, more preferably 170% or more, further preferably 180% or more, further preferably 200% or more, particularly preferably 250% or more, and further preferably 300% or more. The upper limit of the tensile elongation at break is not particularly limited, but is preferably 1000% or less, more preferably 700% or less, and further preferably 500% or less.

[0218] By using the composition, a soft film or molded product can be obtained, and when these are stretched or thermoformed, secondary processing can be performed well.

[0219] The tensile modulus and the tensile elongation at break can be adjusted by appropriately adjusting the blending ratio of the acetalized product (A) and the resin (B) in the composition.

[0220] The tensile elastic modulus and the tensile elongation at break can be measured by the same method as the tensile elastic modulus and the tensile elongation at break of the acetalized product (A) at 23° C. and 50% RH.

[0221] In the composition of the present invention, the melting peak temperature Tm (°C) measured in accordance with JIS K7121:2012 is preferably 136°C or higher, more preferably 138°C or higher, further preferably 140°C or higher, further preferably 142°C or higher, particularly preferably 145°C or higher, and is preferably 190°C or lower, more preferably 185°C or lower, further preferably 183°C or lower, particularly preferably 165°C or lower. When the melting peak temperature Tm is at least the above lower limit, heat resistance such as retort resistance is easily improved, and when it is at most the above upper limit, transparency and moldability are easily improved.

[0222] The above-mentioned melting peak temperature can be adjusted by appropriately adjusting the blending ratio of the acetalized product (A) and the resin (B) in the composition.

[0223] The above-mentioned melting peak temperature can be measured by the same method as the melting peak temperature of the acetalized product (A).

[0224] In a preferred embodiment of the present invention, the composition of the present invention shows a low oxygen permeability, a low tensile elastic modulus, a high tensile elongation at break, and a high melting peak temperature as described above. In addition, in a preferred embodiment of the present invention, a resin film obtained from the composition of the present invention shows the same values ​​of haze and stretchability as the resin film of the present invention described in the section [resin film, barrier material, molded article] described later. Therefore, the composition of the present invention can form a resin film having excellent barrier properties, transparency, stretchability, flexibility, and heat resistance.

[0225] The acetal compound and the composition of the present invention are not particularly limited in their uses, and can be used in various fields as barrier materials or molded articles. Since they have a low oxygen permeability, they are particularly suitable for use in packaging materials for food, cosmetics, and medical chemicals in the form of bags, tubes, cups, and soft bags, and in laminates with rubber such as tire innerliners.

[0226] 〔Resin films, barrier materials, molded products〕

[0227] The present invention includes a resin film comprising one or more layers containing the acetal compound of the present invention. In a preferred embodiment, the resin film is formed of one or more layers containing the acetal compound of the present invention. In a preferred embodiment, the layers do not contain any resin other than the acetal compound of the present invention.

[0228] The present invention also includes the aforementioned resin film, which further includes one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters, and polyurethanes. In a preferred embodiment, the aforementioned resin film is formed by one or more layers containing the acetal compound of the present invention and one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters, and polyurethanes. In a preferred embodiment, the aforementioned further included layer does not contain a resin other than one or more resins selected from the group consisting of polyolefins, polyamides, polyesters, and polyurethanes.

[0229] In addition, the present invention includes a resin film comprising one or more layers containing the composition of the present invention. In a preferred embodiment, the resin film is formed by one or more layers containing the composition of the present invention. In a preferred embodiment, the layer does not contain a resin other than the resin contained in the composition of the present invention.

[0230] The present invention also includes the aforementioned resin film, which further includes one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes. In a preferred embodiment, the aforementioned resin film is formed by one or more layers containing the composition of the present invention and one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes. In a preferred embodiment, the aforementioned layer further includes no resin other than one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes.

[0231] When the resin film includes a further layer in addition to the layer containing the acetal compound (A) of the present invention or the composition of the present invention, that is, as an example of the layer configuration in the case of a multilayer structure, the layer containing the acetal compound (A) of the present invention or the composition of the present invention, which is often used as a barrier material, is represented as "Barrier (barrier layer)", the adhesive resin is represented as "Ad", the above-mentioned further layer is represented as "R", and the recycled resin layer or recycled composition layer is represented as "Reg", Barrier / R, R / Barrier / R, Barrier / Ad / R, Reg / Barrier / R, R / Ad / Barrier / Ad / R, R / Reg / Ad / Barrier / Ad / Reg / R, etc. can be listed, but it is not limited to them. When the multilayer structure includes a plurality of Barriers, R, and Ad, they may be the same Barriers, R, and Ad, or different Barriers, R, and Ad. Each layer may be a single layer or a multilayer. In addition, R may include recycled resins and / or recycled compositions. Here, the recycled resin or recycled composition refers to a resin or composition obtained by recycling the resin film, barrier material or molded article of the present invention for the purpose of reuse and optionally pulverizing the recovered resin or recycled composition.

[0232] The layer containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes as a further layer may contain one or more of the above-mentioned various additives as necessary.

[0233] The polyolefin used in the present invention is not particularly limited. As examples thereof, homopolymers or copolymers of olefins such as linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymers, ethylene-propylene copolymers, polypropylene, propylene-α-olefin copolymers (α-olefins with 4 to 20 carbon atoms), polybutene, and polypentene can be cited. As examples of copolymer components other than these α-olefins, vinyl compounds such as dienes, N-vinyl carbazole, vinyl chloride, vinylidene chloride, styrene, acrylonitrile, and vinyl ether can be cited; unsaturated carboxylic acids such as maleic acid, acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, and itaconic acid, their esters, their anhydrides, or substances obtained by adding hydroxyl groups or epoxy groups to them, etc. For example, copolymers of graftable monomers and polyolefins, or various copolymers such as ionomer resins, which are reactants of α-olefin / α,β-unsaturated carboxylic acid copolymers and ionic metal compounds, can also be used. In addition, chlorinated polyethylene, chlorinated polypropylene, etc. can also be used as polyolefins. These polyolefins can be used alone, or two or more can be used in combination.

[0234] Among the above examples, polypropylene, polyethylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer are particularly preferably used.

[0235] Examples of the polyamide used in the present invention include polycaprolactam (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecanamide (nylon-11), polylaurolactam (nylon-12), polyethylene adipamide (nylon-2,6), polybutylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sebacate (nylon-6,10), polyhexamethylene dodecanediamide (nylon-6,12), polyoctane adipamide (nylon-8,6), polydecane adipamide (nylon-10,6), polydodecane adipamide (nylon-12,10), caprolactam / Lauryl lactam copolymer (nylon-6 / 12), caprolactam / ω-aminononanoic acid copolymer (nylon-6 / 9), caprolactam / hexamethylenediamine adipamide copolymer (nylon-6 / 6,6), lauryl lactam / hexamethylenediamine adipamide copolymer (nylon-12 / 6,6), hexamethylenediamine adipamide / hexamethylenediamine sebacate copolymer (nylon-6,6 / 6,10), ethylenediamine adipamide / hexamethylenediamine adipamide copolymer (nylon-2,6 / 6,6), caprolactam / hexamethylenediamine adipamide / hexamethylenediamine sebacate copolymer (nylon-6 / 6,6 / 6,10), polyhexamethyleneisophthalamide, polyhexamethyleneterephthalamide, hexamethyleneisophthalamide / hexamethyleneterephthalamide copolymer, etc. These polyamides may be used alone or in combination of two or more.

[0236] Among the above examples, polyamides containing a caprolactam component (for example, nylon-6, nylon-6,12, nylon-6 / 12, nylon-6 / 6,6, etc.) are preferred.

[0237] The polyester used in the present invention is not particularly limited. Preferred examples thereof include poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene terephthalate / ethylene isophthalate), poly(ethylene glycol / cyclohexanedimethanol / terephthalate), etc. Among these, poly(ethylene terephthalate) is particularly preferred. It should be noted that as the aforementioned polyester, polyesters containing glycols such as ethylene glycol, butanediol, cyclohexanedimethanol, neopentyl glycol, pentanediol, or dicarboxylic acids such as isophthalic acid, benzophenone dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, propylene bis(phenyl carboxylic acid), diphenyl ether dicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and diethylsuccinic acid as copolymer components may also be used.

[0238] The polyurethane used in the present invention is not particularly limited, and examples thereof include polyether polyurethane, polyester polyurethane, and the like.

[0239] As the resin contained in the above-mentioned further layer, an elastomer is also preferably used. Therefore, in one embodiment of the present invention, the resin film includes one or more layers containing the acetal compound or composition of the present invention and one or more layers containing the elastomer. In another embodiment of the present invention, the resin film is formed by one or more layers containing the acetal compound or composition of the present invention and one or more layers containing the elastomer. In one of these embodiments, the layer containing the acetal compound or composition of the present invention does not contain a resin other than the acetal compound of the present invention or a resin other than the resin contained in the composition of the present invention, and / or the layer containing the elastomer does not contain a resin other than the elastomer.

[0240] The elastomer used in the present invention is not particularly limited, but preferred examples thereof include polyurethane elastomers, polystyrene elastomers, polyamide elastomers, polyester elastomers, polyolefin elastomers, and elastomers formed from copolymers of vinyl aromatic compounds and conjugated diene compounds.

[0241] Among the exemplified elastomers, a polyurethane elastomer is preferably used from the viewpoint of excellent interlayer adhesion between a layer containing the acetalized product of the present invention or a layer containing the composition of the present invention and a layer containing a polyurethane elastomer.

[0242] The thickness of one layer of the layer in the resin film is preferably 0.5 μm or more, more preferably 1 μm or more, and further preferably 5 μm or more, and is preferably 250 μm or less, more preferably 200 μm or less, further preferably 150 μm or less, further preferably 100 μm or less, particularly preferably 60 μm or less, further particularly preferably 50 μm or less, and further particularly preferably 30 μm or less. When the layer in the resin film is a plurality of layers, the thickness of one layer of the plurality of layers in the resin film may be the same or different.

[0243] From the viewpoint of easily improving the barrier properties, the thickness of the resin film is preferably 1 μm or more, more preferably 5 μm or more, and further preferably 10 μm or more. From the viewpoint of flexibility, the thickness is preferably 1000 μm or less, more preferably 750 μm or less, further preferably 500 μm or less, further preferably 250 μm or less, particularly preferably 100 μm or less, more particularly preferably 50 μm or less, and further particularly preferably 30 μm or less.

[0244] The thickness of a single layer in the resin film and the thickness of the resin film can be measured using a conventionally known method, for example, a contact type or non-contact type thickness meter or the like.

[0245] The resin film of the present invention has excellent transparency. The haze of the resin film of the present invention is preferably 5% or less, more preferably 3% or less, further preferably 2% or less, further preferably 1% or less, particularly preferably 0.5% or less, more particularly preferably 0.3% or less, and further particularly preferably 0.2% or less. The lower the haze, the higher the transparency of the resin film. Therefore, the lower limit is not particularly limited, and for example, it may be 0.01% or more. It should be noted that the haze of the resin film is measured using a haze meter in accordance with JIS K7136:2000.

[0246] The resin film of the present invention has excellent stretchability. Therefore, as a stretched film, it can be particularly suitably used as a stretched film formed by stretching at least 2 times in a uniaxial direction. In addition, the aforementioned stretched film can be suitably used as a heat shrinkable film.

[0247] The stretchability can be evaluated by, for example, the method described in Examples below.

[0248] In a preferred embodiment of the present invention, the resin film of the present invention shows the same values ​​of oxygen permeability, tensile elastic modulus, tensile elongation at break and melting peak temperature as the acetal product or composition of the present invention described in the above-mentioned [Acetal product of ethylene vinyl alcohol copolymer] and [Composition].

[0249] The resin film of the present invention is excellent in barrier properties, transparency, stretchability, flexibility, and heat resistance. Therefore, a barrier material and a molded article formed from the resin film of the present invention can also have the above-mentioned excellent physical properties.

[0250] The present invention also includes a barrier material comprising the resin film of the present invention and a molded product comprising the resin film of the present invention.

[0251] Barrier materials or molded bodies include packaging materials, coating materials, covering materials, pads, wallpapers, decorative panels, partitions, films, heat shrinkable films (skin packaging films, etc.), stretch films, flexible films, flexible packaging materials, containers, bags, bottles, cups, trays, soft bags, pipes, hoses, tubes, hollow balls, irregularly shaped molded bodies, tire airtight layers, etc.

[0252] [Method for producing resin film, barrier material or molded body]

[0253] The method for manufacturing the resin film, barrier material or molded body of the present invention is not particularly limited. The acetal compound of the present invention or the composition of the present invention can be molded into a film or various molded bodies by known methods such as extrusion molding, pressure molding, blow molding, injection molding, solution casting, etc. The resin film, barrier material or molded body of the present invention can also be recycled for the purpose of reuse, crushed and molded again according to the circumstances. In addition, the resin film can also be subjected to secondary processing such as uniaxial stretching or biaxial stretching and thermoforming.

[0254] As a method for manufacturing a resin film, extrusion molding is suitable. In this method, the acetal compound or composition of the present invention is supplied to an extruder, and after mixing and melting, the resulting molten kneaded product is extruded from a mold, and is pulled by a traction machine to be formed into a film. The temperature of the resin or composition during extrusion can be selected according to the composition of the resin or composition, for example, 140 to 270°C, preferably 170 to 250°C, more preferably 180 to 240°C, and further preferably 190 to 220°C. If the temperature of the resin or composition during extrusion is below the above upper limit, the decomposition of the acetal compound or composition can be suppressed, and it is not easy to color. In addition, if the temperature of the resin or composition during extrusion is above the above lower limit, the acetal compound or composition is completely melted, and a resin film with good appearance is easily obtained, and the generation of volatile substances is easily suppressed. In addition, in order to effectively remove volatile substances, it is preferred to remove volatile substances from the vent of the extruder by reducing pressure.

[0255] In order to improve the barrier properties and shape retention under high temperature and high humidity, or to improve the shrinkage when used for applications such as heat shrinkable films, a cross-linked structure can be applied to the resin film, barrier material and molded body of the present invention to the extent that the effect of the present invention is not impaired. In this case, the composition of the present invention usually contains a cross-linking aid. The method of applying the cross-linked structure is not particularly limited, and as a preferred method, a method of irradiating energy rays can be listed. As energy rays, ionizing radiation such as ultraviolet rays, electron rays, X-rays, α rays, and γ rays can be listed, and electron rays can be preferably listed.

[0256] Regarding the electron beam irradiation method, there can be cited the method of introducing a resin film or a barrier material or a molded body into an electron beam irradiation device after a primary process such as extrusion molding, and irradiating the body with electron beams. There is no particular limitation on the dose of electron beams, but it is preferably 1 to 40 Mrad, and more preferably 2 to 30 Mrad. If the amount of electron beams irradiated is above the aforementioned lower limit, crosslinking is easily performed sufficiently. On the other hand, if the amount of electron beams irradiated is below the aforementioned upper limit, degradation of the molded body is easily prevented.

[0257] For a molded body that needs to be subjected to secondary processing such as (uniaxial or biaxial) stretching or thermoforming after primary processing, it is suitable to perform electron beam irradiation between the primary processing and the secondary processing.

[0258] As electron beams that can be used, electron beams with energies of 150 to 10,000 KeV emitted by various electron beam accelerators such as the Cockcroft-Walton type, Van de Graaff type, resonant transformer type, insulating core transformer type, linear accelerator, dynamometer type, and high-frequency cyclotron accelerator are generally used, but are not limited to these.

[0259] When manufacturing a multilayer resin film, barrier material or molded body, for example, there can be mentioned a method of melt-extruding a film formed of the acetal compound or composition of the present invention with other resins or compositions; conversely, a method of melt-extruding a film formed of other resins or compositions with the acetal compound or composition of the present invention; a method of co-extruding the acetal compound or composition of the present invention with other resins or compositions; a method of laminating a film formed of the acetal compound or composition of the present invention with a film formed of other resins or compositions using a known adhesive as appropriate, etc. Among these, the co-extrusion molding method is preferably used.

[0260] The method of co-extrusion molding is not particularly limited. For example, as suitable methods, a multi-manifold method, a feed block method, a multi-slit die method, etc. can be exemplified. By this molding method, a multi-layer film, a multi-layer sheet, a multi-layer conduit, a multi-layer hose, a multi-layer irregular shaped molded body, etc. can be molded. In addition, a multi-layer film or a multi-layer bottle can also be manufactured by a co-extrusion inflation molding method, a co-extrusion blow molding method, etc. Furthermore, by subjecting the multi-layer resin film or molded body to secondary processing, a molded body with a desired shape can also be manufactured. Secondary processing includes, for example, stretching or heat treatment in a uniaxial direction or a biaxial direction, calendering, vacuum molding, pressure molding, vacuum pressure molding, stretch blow molding, blow molding, etc.

[0261] When a film formed from the acetal compound or composition of the present invention is laminated with a film formed from another resin or composition, known adhesives used depending on the situation include, for example, organic titanium compounds, isocyanate compounds, polyester compounds, and carboxylic acid-modified polyolefins, and carboxylic acid-modified polyolefins are preferably used.

[0262] Example

[0263] Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0264] The analysis methods and the measurement methods of various physical properties of the ethylene vinyl alcohol copolymer (EVOH) used as a raw material and the acetalized product of the obtained ethylene vinyl alcohol copolymer in the Examples and Comparative Examples, and the evaluation method of the resin film are as follows.

[0265] <Content of each monomer unit and degree of acetalization>

[0266] The ethylene vinyl alcohol copolymers used as raw materials in the examples and comparative examples, and the acetalized products of the ethylene vinyl alcohol copolymers obtained in the examples and comparative examples, were analyzed for the contents (units: mol %) of ethylene units, vinyl alcohol units, and acetalized vinyl alcohol units, i.e., acetal units, and the degree of acetalization in the ethylene vinyl alcohol copolymers and their acetalized products as follows.

[0267] At 120°C, ethylene vinyl alcohol copolymer was dissolved in dimethyl sulfoxide (DMSO), and the obtained DMSO solution was cooled to room temperature. Thereafter, N,N-dimethyl-4-aminopyridine and acetic anhydride were added to the aforementioned DMSO solution, and the mixture was stirred for 1 hour to react. The copolymer was reprecipitated from the obtained reaction solution using ion exchange water and acetone, washed, and then dried to obtain ethylene vinyl acetate copolymer. The deuterated dimethyl sulfoxide (DMSO-d6) solution of the obtained ethylene vinyl acetate copolymer was measured using a 400MHz proton NMR measuring device with a cumulative frequency of 256 times. In the obtained spectrum, the content (n) of the ethylene unit relative to all monomer units constituting the ethylene vinyl alcohol copolymer was calculated based on the intensity ratio of the peak (1.1 to 1.9ppm) of the methine protons derived from the ethylene unit and the vinyl acetate unit in the ethylene vinyl acetate copolymer to the peak (2.0ppm peak) of the terminal methyl protons derived from the vinyl acetate unit.

[0268] Since the ethylene unit is not affected by the acetalization reaction, the content (n) of the ethylene unit in the ethylene vinyl alcohol copolymer is equivalent to the content (n) of the ethylene unit relative to all monomer units constituting the acetalized product of EVOH obtained after acetalization of the ethylene vinyl alcohol copolymer.

[0269] The content of vinyl alcohol units (l), the content of vinyl acetate units (m) and the content of acetal units (k) relative to all monomer units constituting the acetalized product of EVOH were determined by the following method. The DMSO-d6 solution of the acetalized product of EVOH was measured using a 400 MHz proton NMR measuring device with a cumulative frequency of 256 times. Based on the obtained spectrum, the content of each monomer unit was calculated using the intensity ratio of the peaks of the substituent protons (peaks of 1.0 to 1.8 ppm) derived from the ethylene units, vinyl alcohol units and vinyl acetate units and the peaks (peaks of 0.8 to 1.0 ppm) derived from the terminal methyl protons of the acetal units, and the content of the ethylene units (n) of the ethylene vinyl alcohol copolymer.

[0270] The acetalization degree of the acetalized product of EVOH is determined by the following formula using the content (l) of the vinyl alcohol unit, the content (m) of the vinyl ester unit, and the content (k) of the acetal unit determined above.

[0271] Acetalization degree (mol%) = {k / (k+l+m)}×100

[0272] <Pore median diameter, pore surface area>

[0273] The EVOH porous body obtained in each of the manufacturing examples described below or the EVOH acetal obtained in the examples and comparative examples were freeze-dried at -80°C. 0.5 g of it was measured and placed in a standard 5cc powder dish (sleeve volume 0.4cc), and the median particle size and pore surface area of ​​pores with a pore diameter range of 0.005 to 100 μm were measured using a pore distribution measuring device (AutoPore V9620 manufactured by Micromeritics) under an initial pressure of 2.6 kPa. The median particle size of the pores refers to the median particle size (d50) of all pores with a pore diameter range of 0.005 to 100 μm in the Log differential pore volume distribution. It should be noted that with regard to mercury parameters, the mercury contact angle is set to 130 degrees and the mercury surface tension is set to 485 dyn / cm.

[0274] <Average particle size>

[0275] The average particle size of the sample for measurement (freeze-dried EVOH pellets) was measured using "CAMSIZER X2" of Verder Scientific Co., Ltd. for 100 g of the ethylene vinyl alcohol copolymer obtained in the later-described Production Examples 1 to 6. The particle size (Q3 50.0%) at which the cumulative particle size distribution from the smaller particle size side of the circle equivalent particle size calculated by the dynamic image analysis method based on ISO 13322-2 (2006) becomes 50% (volume basis) was set as the average particle size.

[0276] <Melt Flow Rate (MFR)>

[0277] The melt flow rates of the ethylene vinyl alcohol copolymers used as raw materials in Examples and Comparative Examples and the acetalized products of the ethylene vinyl alcohol copolymers obtained in Examples and Comparative Examples were measured under the conditions of 190° C. and a load of 2.16 kg in accordance with JIS K7210:2014.

[0278] <Symmetry coefficient (W 0.05h / 2f)>

[0279] The symmetry coefficient of the acetal compounds obtained in the examples and comparative examples was determined by reverse phase partition gradient high performance liquid chromatography (HPLC) analysis using a water-ethanol eluent according to JIS K 0124:2011 under the following conditions. 0.05h " represents the peak width at a height of 1 / 20 of the peak height from the baseline of the measured peak obtained by HPLC analysis (peak 5% height position), and "f" represents the distance on the rising side of the peak when the peak width at the peak 5% height position is divided into two parts by a vertical line including the peak apex.

[0280] (Determination Conditions for HPLC Analysis)

[0281] Sample Concentration: 1.5 mg / 1 g

[0282] Sample Solvent: Mixed solvent of EtOH (99.5%) / Ion-exchanged water = 9 / 1 wt%

[0283] Injection Volume: 20 μL

[0284] Detector: Varian 380-LC, EVAP 80 °C (front-stage heating), NEB 50 °C (second-stage heating), Gas 1.5 (SLM), Data Reading Interval: 1000 msec, Filter: 1 μm

[0285] ODS Silica Column: "Shimpack G-ODS (octadecyl-modified spherical fully porous silica gel, inner diameter 4 mm × length 10 mm, particle size 5 μm)" manufactured by Shimadzu Corporation

[0286] Column Temperature: 45 °C

[0287] Liquid Delivery Flow Rate: Total flow rate is 0.4 mL / min

[0288] (Steps for HPLC Analysis)

[0289] As mobile phase A, water is used, and as mobile phase B, ethanol (99.5%) is used. At the moment before injecting the sample, the inside of the column of the HPLC system is filled with a mixed solvent of mobile phase A / mobile phase B at a volume ratio of 95 / 5. The sample is injected in this state. And the solvent is circulated under the following conditions.

[0290] 0 - 5 minutes (B concentration; constant at 5%)

[0291] 5 - 25 minutes (B concentration; from 5% to 100%)

[0292] 25 - 30 minutes (B concentration; constant at 100%)

[0293] 30 - 31 minutes (B concentration; from 100% to 5%)

[0294] 31 - 55 minutes (B concentration; constant at 5%)

[0295] <Tm / Tg (K / K) and Tm (°C)>

[0296] The following temperatures were measured in accordance with JIS K7121:2012: The acetals obtained in the examples and comparative examples were heated from 25°C to 230°C at a heating rate of 10°C / min to melt, cooled from 230°C to -30°C at a cooling rate of 10°C / min, and then heated from -30°C to 230°C again at a heating rate of 10°C / min, and the melting peak temperature Tm (°C) and the midpoint glass transition temperature Tg (°C) were measured. The obtained values ​​were converted into absolute temperature (K) units, and Tm / Tg (K / K) was calculated.

[0297] In addition, the melting peak temperature Tm (° C.) of the compositions obtained in Examples and Comparative Examples was measured in the same manner.

[0298] <Oxygen permeability at 20°C, 65% RH>

[0299] The resin films obtained in the examples and comparative examples were heat treated for 10 minutes at a melting point of -20°C. Two sheets of each resin film were humidified at 20°C and 65%RH for 5 days. Then, the oxygen permeation rate was measured at 20°C and 65%RH using MOCON OX-TRAN 2 / 20 manufactured by Modern Control in accordance with JIS K7126 (isobaric method) to obtain the average value.

[0300] <Crystal Melting Heat ΔH>

[0301] ΔH was measured in accordance with JIS K7121: 2012. More specifically, the acetalized products obtained in Examples and Comparative Examples were heated from 25°C to 140°C at a heating rate of 10°C / min using DSC, maintained at 140°C for 30 minutes, then cooled from 140°C to -30°C at a cooling rate of 4°C / min, and then heated from -30°C to 200°C at a heating rate of 10°C / min to determine ΔH.

[0302] <{ΔH×Tm×amount of vinyl alcohol units / 100} / (oxygen permeability at 20°C and 65% RH)>

[0303] For the acetal products obtained in Examples and Comparative Examples, {ΔH×Tm×vinyl alcohol unit amount / 100} / (oxygen permeability at 20°C and 65%RH) was calculated using ΔH, Tm, vinyl alcohol unit amount and oxygen permeability at 20°C and 65%RH determined as above.

[0304] <Film Formability>

[0305] The acetalized products and compositions obtained in Examples and Comparative Examples were film-formed using a film-forming machine consisting of a 40φ extruder (PLABOR GT-40-A manufactured by Plastics Engineering Research Institute) and a T die under the following extrusion conditions to obtain a single-layer resin film having a thickness of 20 μm.

[0306]

[0307] Cylinder and mold temperature settings: C1 / C2 / C3 / adapter / mold = 180 / 200 / 210 / 210 / 210 (° C.) The film forming stability at this time was observed and evaluated according to the following criteria as an index of film forming properties.

[0308] (Evaluation criteria for film forming properties)

[0309] A: Continuous film formation was possible without any problem, and a resin film with good appearance was obtained.

[0310] B: Although problems such as breakage and loosening occurred at a part of the edge of the resin film, continuous film formation was possible, and a resin film with relatively good appearance was obtained.

[0311] C: Problems such as breakage and / or loosening of the resin film occurred, and continuous film production could not be achieved, and a resin film with good appearance could not be obtained.

[0312] <Stretchability>

[0313] The resin films obtained in Examples and Comparative Examples were set in a pantograph biaxial stretching apparatus manufactured by Toyo Seiki Co., Ltd. and simultaneously biaxially stretched at a stretching ratio of 2×2 at 60° C. The appearance of the film after stretching was evaluated according to the following evaluation criteria.

[0314] (Evaluation criteria for stretchability)

[0315] A: There is no unevenness or local uneven thickness.

[0316] B: There is obvious unevenness and obvious unevenness in thickness.

[0317] C: The film is damaged.

[0318] <Tensile elongation at break and tensile modulus at 23°C, 50% RH>

[0319] After the resin films obtained in the examples and comparative examples were humidified at 23°C and 50% RH for 7 days, 5 short strip test pieces with a width of 15 mm were prepared for each resin film. The test pieces were mounted on Autograph AGS-H manufactured by Shimadzu Corporation, and a tensile test was performed under the conditions of a chuck interval of 50 mm and a tensile speed of 500 mm / min. The tensile elongation at break and the tensile elastic modulus were obtained, and the average values ​​of each were calculated.

[0320] <Transparency (Haze of Resin Film)>

[0321] A test piece of 20 mm in length×5 mm in width was cut out from the resin film obtained in Examples and Comparative Examples. The haze of the obtained test piece was measured using a haze meter (SH7000 manufactured by Nippon Denshoku Industries) in accordance with JIS K7136:2000.

[0322] In the examples and comparative examples, pelletized ethylene vinyl alcohol copolymers (EVOH1 to EVOH6) produced by the following method were used as raw materials.

[0323] <Production Example 1>

[0324] An EVOH solution containing 100 parts by mass of EVOH having an ethylene unit content of 44 mol% and a saponification degree of 99.98 mol%, 60 parts by mass of methanol and 40 parts by mass of water was continuously supplied from the top section of a plate tower having a tower diameter of 0.3 m and 10 stages, and water vapor was blown in from the bottom section so that the EVOH solution and the water vapor were in contact by convection. The temperature in the tower was 130°C and the pressure in the tower was 0.3 MPa. The water-containing EVOH obtained by convection contact with the water vapor was taken out from the bottom of the tower. The temperature of the obtained water-containing EVOH was 120°C and the water content was 52.4% by mass. In addition, the methanol content was 0.02% by mass.

[0325] The water-containing EVOH is supplied to a twin-screw extruder with a back slit at 42 kg / hr, and extruded from a die with a hole diameter of 3.0 mm and 8 holes installed at the front end of the extruder under the following conditions. The extruded melt is cut at a distance of 0.05 mm from the die with a heating cutter with two blades to obtain a flat spherical EVOH porous body. The flow rate of the cutter circulating water is 300 liters / minute, and the rotation speed of the cutter blade is 3000 rpm. The resin temperature (exit) at this time is 95°C, and the moisture content is 34% by mass.

[0326] <Conditions of Twin Screw Extruder>

[0327] L / D: 14

[0328] Diameter: 30mm

[0329] Screw: Full thread

[0330] Speed: 300rpm

[0331] Cylinder temperature: 90℃

[0332] Mold temperature: 120℃

[0333] The obtained EVOH porous body was washed with water at 50° C. until the sodium acetate content became 0.002 mass % or less in terms of sodium, and the washing water was filtered off to obtain a porous body (EVOH1) of ethylene vinyl alcohol copolymer in the form of flat spherical pellets.

[0334] The obtained EVOH1 was a flat spherical pellet with an average particle size of 3.2 mm. The EVOH1 pellet had pores with a diameter of 0.003 μm to 100 μm, and the median particle size of the pores was 0.07 μm. The median particle size of the pores, the pore surface area, and the average particle size of the obtained EVOH1 are shown in Table 1.

[0335] <Production Example 2>

[0336] A porous body (EVOH2) of an ethylene vinyl alcohol copolymer in the form of pellets was obtained in the same manner as in Production Example 1 except that the ethylene content was changed to 32 mol %.

[0337] The obtained EVOH2 pellets were flat spherical with an average particle size of 3.2 mm. The EVOH2 pellets had pores with diameters of 0.003 μm to 100 μm, and the median particle size of the pores was 0.11 μm.

[0338] Table 1 shows the median particle size of the pores, the pore surface area, and the average particle size of the obtained EVOH2.

[0339] <Production Example 3>

[0340] The ethylene vinyl alcohol copolymer (EVOH1) obtained in Production Example 1 was fed into a twin-screw extruder and pelletized at a resin temperature of 100° C. at the ejection port. The amount of EVOH1 fed per unit time was 10 kg / hr. The specifications of the twin-screw extruder are as follows.

[0341] <Conditions of Twin Screw Extruder>

[0342] L / D:45.5

[0343] Diameter: 30mmΦ

[0344] Screw: Fully jointed

[0345] Speed: 300rpm

[0346] Mould diameter: 3.0mmΦ

[0347] Number of mold holes: 5

[0348] The obtained pellets were dried at 100° C. for 15 hours using a fluidized dryer and then dried at 100° C. for 15 hours using a static dryer to obtain pelletized ethylene vinyl alcohol copolymer (EVOH3).

[0349] The obtained EVOH 3 pellets were spherical with an average particle size of 2.9 mm, and observation using an electron microscope revealed that no pores were found in the EVOH 3. The average particle size of the obtained EVOH 3 is shown in Table 1.

[0350] <Production Example 4>

[0351] A porous body (EVOH4) of an ethylene vinyl alcohol copolymer in the form of pellets was obtained in the same manner as in Production Example 1 except that the ethylene content was changed to 27 mol %.

[0352] The obtained EVOH4 pellets were flat spherical with an average particle size of 3.2 mm. The EVOH4 pellets had pores with diameters of 0.003 μm to 100 μm, and the median particle size of the pores was 0.11 μm.

[0353] Table 1 shows the median particle size of the pores, the pore surface area, and the average particle size of the obtained EVOH4.

[0354] <Production Example 5>

[0355] A porous body (EVOH5) of an ethylene vinyl alcohol copolymer in the form of pellets was obtained in the same manner as in Production Example 1 except that the ethylene content was changed to 15 mol %.

[0356] The obtained EVOH5 pellets were flat spherical with an average particle size of 3.2 mm. The EVOH5 pellets had pores with diameters of 0.003 μm to 100 μm, and the median particle size of the pores was 0.05 μm.

[0357] Table 1 shows the median particle size of the pores, the pore surface area, and the average particle size of the obtained EVOH5.

[0358] <Production Example 6>

[0359] The ethylene vinyl alcohol copolymer (EVOH3) obtained in Production Example 3 was crushed using SupermasscolloiderMKCA6-5 at a gap of 100 μm and a rotation speed of 1800 rpm to obtain EVOH6. The obtained EVOH6 was observed using an electron microscope, and it was confirmed that EVOH6 had no pores. The average particle size of the obtained EVOH6 is shown in Table 1.

[0360] <Example 1>

[0361] (Synthesis of acetalized product of ethylene vinyl alcohol copolymer)

[0362] 100 parts by mass of the EVOH porous body (EVOH2) obtained in Manufacturing Example 2 is dispersed in 377 parts by mass of water, 29.7 parts by mass of isobutyraldehyde is added, and the resulting dispersion is heated to 60°C while stirring. Stirring is continued for 5 hours to allow the isobutyraldehyde to penetrate into the ethylene vinyl alcohol copolymer. Next, 10 parts by mass of 1M hydrochloric acid is added to the above-mentioned dispersion at 60°C to carry out an acetalization reaction. 2 hours after the first addition of hydrochloric acid, 20 parts by mass of 1M hydrochloric acid is added, and the acetalization reaction is further carried out for 12 hours (a total of 14 hours). The acetalized product generated by acetalization is in a solid state. Thereafter, 75 parts by mass of 1M sodium hydroxide is added to the dispersion and neutralized to stop the acetalization reaction. Neutralization occurs until the inside of the solid of the acetalized product, so the dispersion is further stirred at 60°C for 8 hours. The neutralized acetal was filtered out, 500 parts by weight of ion exchange water was added to the acetal, and the mixture was stirred at 60°C for 6 hours to wash the acetal. The acetal was filtered out again, 500 parts by weight of ion exchange water was added to the acetal, and the mixture was stirred at 60°C for 6 hours to wash the acetal for the second time. The washing water was filtered out, and vacuum drying was performed at 60°C for 8 hours to obtain 113 parts by weight of acetal (A-1) of ethylene vinyl alcohol copolymer in the form of pellets (yield: 100%). The obtained acetal of EVOH is a porous body having the same pore structure as that of EVOH2 used as a raw material.

[0363] The acetalized EVOH obtained above was film-formed using a film-forming machine consisting of a 40φ extruder (PLABOR GT-40-A manufactured by Plastics Engineering Research Institute) and a T die under the following extrusion conditions to obtain a single-layer resin film having a thickness of 20 μm.

[0364]

[0365] Cylinder and mold temperature settings: C1 / C2 / C3 / adapter / mold = 180 / 200 / 210 / 210 / 210 (℃)

[0366] Using the obtained resin film, physical properties of the resin film were evaluated.

[0367] <Examples 2 to 7>

[0368] Except that the type of ethylene vinyl alcohol copolymer and the acetalization reaction conditions were changed as shown in Table 1, the same operation as in Example 1 was performed to obtain pelletized ethylene vinyl alcohol copolymer acetals (A-2) to (A-7). Among the obtained acetals of ethylene vinyl alcohol copolymer, (A-2) to (A-6) were porous bodies having the same pore structure as the ethylene vinyl alcohol copolymer as the raw material. Using the obtained acetals of ethylene vinyl alcohol copolymer, the same operation as in Example 1 was performed to obtain a melt-kneaded product and a resin film.

[0369] <Comparative Examples 1, 3 and 4>

[0370] The same operation as in Example 1 was performed except that the type of ethylene vinyl alcohol copolymer and the acetalization reaction conditions were changed as shown in Table 1 to obtain pelletized ethylene vinyl alcohol copolymer acetals (B-1), (B-3) and (B-4). Using the obtained EVOH acetals, the same operation as in Example 1 was performed to obtain a melt-kneaded product and a resin film.

[0371] <Comparative Example 2>

[0372] 100 parts by mass of the EVOH porous body (EVOH1) obtained in Manufacturing Example 1 is dispersed in a mixed solvent of 500 parts by mass of methanol and 50 parts by mass of ion exchange water. Next, 40 parts by mass of 1M hydrochloric acid is added, and the temperature of the obtained dispersion is raised to 60°C under stirring to completely dissolve the EVOH1 pellets. 16.7 parts by mass of isobutyraldehyde is added to the obtained solution, and after mixing until uniformity is achieved, the acetalization reaction is maintained at 60°C. At the moment of maintaining the reaction for 2 hours from the start of the reaction, 60 parts by mass of 1M sodium hydroxide is added for neutralization, thereby stopping the acetalization reaction and obtaining a reaction solution containing an acetalized product of ethylene vinyl alcohol copolymer.

[0373] After adding 500 parts by mass of methanol to the neutralized reaction solution, the resulting liquid is dripped into 2000 parts by mass of ion exchange water to precipitate the acetal of ethylene vinyl alcohol copolymer. The precipitated acetal is filtered out, and the filtered acetal is dispersed in ion exchange water, stirred at 23°C for 15 minutes, washed with water, and the acetal is filtered out again. The washing / filtration operation is further repeated 2 times. The washing operation from the precipitation to the washing / filtration is set as 1 group. Next, the acetal is dissolved in 1000 parts by mass of methanol, and 1 group of washing operations is performed again. Vacuum drying is performed at 60°C for 8 hours to obtain the acetal of ethylene vinyl alcohol copolymer (B-2) after washing and vacuum drying. The acetal of ethylene vinyl alcohol copolymer (B-2) has an ethylene unit of 44 mol% and an acetalization degree of 30 mol%.

[0374] Using the obtained acetalized product of ethylene vinyl alcohol copolymer (B-2), the same procedure as in Example 1 was carried out to obtain a melt-kneaded product and a resin film.

[0375] <Comparative Example 5>

[0376] The same operation as in Example 1 was performed except that the type of ethylene vinyl alcohol copolymer and the acetalization reaction conditions were changed as shown in Table 1 to obtain a pelletized ethylene vinyl alcohol copolymer (B-5). The obtained acetalized ethylene vinyl alcohol copolymer was a porous body having the same pore structure as the ethylene vinyl alcohol copolymer as the raw material. Using the obtained acetalized ethylene vinyl alcohol copolymer, the same operation as in Example 1 was performed to obtain a melt-kneaded product and a resin film, respectively.

[0377] <Comparative Examples 6 to 7>

[0378] Using EVOH1 and EVOH2 obtained in Production Examples 1 and 2, the same operation as in Example 1 was carried out to obtain a melt-kneaded product and a resin film, respectively.

[0379] <Comparative Example 8>

[0380] Except having changed the amount of isobutylaldehyde as shown in Table 1, the same operation as in Comparative Example 2 was carried out to obtain an acetalized product (B-6) of an ethylene vinyl alcohol copolymer, and a melt-kneaded product and a resin film were obtained.

[0381] The various physical properties of the resins and resin films obtained in Examples 1 to 7 and Comparative Examples 1 to 8 were evaluated according to the above-mentioned methods.

[0382] [Table 1]

[0383]

[0384] <Example 8>

[0385] 25 parts by mass of the acetalized product of ethylene vinyl alcohol copolymer (A-1) and 75 parts by mass of ethylene vinyl alcohol copolymer (EVOH2) were melt-kneaded using LABO PLASTMIL at a chamber temperature of 210°C and a rotation speed of 90 rpm for 5 minutes. The chamber contents were taken out and cooled to obtain a composition.

[0386] Using the obtained composition, the same operation as in Example 1 was carried out to obtain a resin film.

[0387] <Examples 9 to 12 and Comparative Examples 9 to 10>

[0388] Except having changed the resin used as shown in Table 2, it carried out similarly to Example 8, and obtained the composition and the resin film.

[0389] The compositions and resin films obtained in Examples 8 to 12 and Comparative Examples 9 and 10 were evaluated for various physical properties according to the above methods.

[0390] [Table 2]

[0391] Table 2

[0392]

[0393] As shown in Tables 1 and 2, it was confirmed that the acetalized products and compositions obtained in Examples can provide resin films excellent in barrier properties, transparency, stretchability, flexibility, and heat resistance. On the other hand, it was confirmed that the resins and compositions obtained in Comparative Examples can provide resin films inferior in only one or more of barrier properties, transparency, stretchability, flexibility, and heat resistance.

[0394] As described above, the acetalized product of the ethylene vinyl alcohol copolymer and the composition of the present invention can form a resin film having excellent barrier properties, transparency, stretchability, flexibility and heat resistance.

Claims

1. An acetalized product, which is an acetalized product of an ethylene vinyl alcohol copolymer, comprising 20 to 80 mol% of ethylene units and 4 to 76 mol% of vinyl alcohol units based on all monomer units constituting the acetalized product, The acetalization degree of the acetalized product is 3 to 80 mol %, and satisfies formula (1) and formula (2): 0.71≤W 0.05h / 2f≤1.09 (1) In formula (1), W 0.05h / 2f represents the symmetry coefficient determined by reverse phase partition gradient HPLC analysis using a water-ethanol eluent in accordance with JIS K 0124:2011; 1.20≤Tm / Tg≤1.35 (2) In formula (2), Tm and Tg represent the melting peak temperature (absolute temperature) and the midpoint glass transition temperature (absolute temperature) measured in accordance with JIS K7121:2012, respectively. The oxygen permeability of the acetal compound at 20°C and 65% RH is 150cc·20μm / m 2 ·day·atm or less.

2. The acetal compound according to claim 1, which satisfies formula (3): {ΔH (J / g)×Tm (absolute temperature)×amount of vinyl alcohol units (mol%) / 100} / (oxygen permeation rate at 20°C and 65%RH)≥30 (3). 3 . The acetalized product according to claim 1 , wherein the degree of acetalization is 40 mol % or less. The acetal compound according to any one of claims 1 to 3, which has a melting peak temperature Tm measured in accordance with JIS K7121:2012 of 136°C or higher. 5 . The acetalized product according to claim 1 , which has a tensile elastic modulus at 23° C. and 50% RH of 2000 MPa or less.

6. A composition comprising: (A) the acetal compound according to any one of claims 1 to 5; and (B) one or more resins selected from the group consisting of (B-1) acetalized products of ethylene vinyl alcohol copolymers other than (A), (B-2) ethylene vinyl alcohol copolymers, and (B-3) resins other than (B-1) and (B-2).

7. The method for producing an acetal compound according to any one of claims 1 to 5, wherein include: (i) preparing a dispersion liquid containing an ethylene vinyl alcohol copolymer, an aldehyde and a solvent, and allowing at least a portion of the aldehyde to permeate the ethylene vinyl alcohol copolymer; as well as (ii) after step (i), a step of adding a catalyst to the dispersion to acetalize the ethylene vinyl alcohol copolymer, The acetalization is performed by a solid-liquid reaction. 8 . A resin film comprising one or more layers containing the acetalized product according to claim 1 . 9 . A resin film comprising one or more layers containing the composition according to claim 6 . 10 . The resin film according to claim 8 , further comprising one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes. 11 . The resin film according to claim 9 , further comprising one or more layers containing one or more resins selected from the group consisting of polyolefins, polyamides, polyesters and polyurethanes. 12 . A barrier material comprising the resin film according to claim 8 . 13 . A molded product comprising the resin film according to claim 8 .

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